In adult mammals,optic nerve injury leads to irreversible vision loss due to its extremely limited regenerative capacity.In contrast,adult zebrafish possess a robust capacity for spontaneous visual system regeneration...In adult mammals,optic nerve injury leads to irreversible vision loss due to its extremely limited regenerative capacity.In contrast,adult zebrafish possess a robust capacity for spontaneous visual system regeneration,although the spatiotemporal coordination of recovery across the retina,optic nerve,and brain remains poorly understood.In the present study,the regenerative dynamics following optic nerve transection were systematically characterized in adult zebrafish over a 5 week period using hematoxylin-eosin staining,immunohistochemistry,transmission electron microscopy,single-cell RNA sequencing,and optokinetic response(OKR)behavioral assessments.At 1 week post-injury(1 wpi),retinal ganglion cell depletion was evident but showed significant recovery by 2 wpi.Concurrently,the injured optic nerve displayed a marked increase in diameter and cell number at 2 wpi,including widespread expression of proliferating cell nuclear antigen,consistent with heightened proliferative activity.Single-cell transcriptomic profiling at 2 wpi revealed five principal cell populations:fibroblasts,mural cells,immune cells,mature oligodendrocytes,and myelin-forming oligodendrocytes.By 4-5 wpi,remyelination within the optic nerve and re-establishment of synaptic architecture in the optic tectum were strongly correlated with functional restoration of OKR behavior.These findings provide a comprehensive spatiotemporal framework of visual pathway regeneration in zebrafish,establishing a valuable model for elucidating conserved mechanisms of neural repair with translational potential for human vision restoration.展开更多
Functional recovery in penetrating neurological injury is hampered by a lack of clinical regenerative therapies.Biomaterial therapies show promise as medical materials for neural repair through immunomodulation,struct...Functional recovery in penetrating neurological injury is hampered by a lack of clinical regenerative therapies.Biomaterial therapies show promise as medical materials for neural repair through immunomodulation,structural support,and delivery of therapeutic biomolecules.However,a lack of facile and pathology-mimetic models for therapeutic testing is a bottleneck in neural tissue engineering research.We have deployed a two-dimensional,high-density multicellular cortical brain sheet to develop a facile model of injury(macrotransection/scratch wound)in vitro.The model encompasses the major neural cell types involved in pathological responses post-injury.Critically,we observed hallmark pathological responses in injury foci including cell scarring,immune cell infiltration,precursor cell migration,and shortrange axonal sprouting.Delivering test magnetic particles to evaluate the potential of the model for biomaterial screening shows a high uptake of introduced magnetic particles by injury-activated immune cells,mimicking in vivo findings.Finally,we proved it is feasible to create reproducible traumatic injuries in the brain sheet(in multielectrode array devices in situ)characterized by focal loss of electrical spiking in injury sites,offering the potential for longer term,electrophysiology plus histology assays.To our knowledge,this is the first in vitro simulation of transecting injury in a two-dimensional multicellular cortical brain cell sheet,that allows for combined histological and electrophysiological readouts of damage/repair.The patho-mimicry and adaptability of this simplified model of brain injury could benefit the testing of biomaterial therapeutics in regenerative neurology,with the option for functional electrophysiological readouts.展开更多
Enhanced sulfur and nitrogen deposition has been observed in many transect regions worldwide,from urban/agricultural areas to mountains.The Sichuan Basin(SCB),with 18 prefectural cities,is the most economically-develo...Enhanced sulfur and nitrogen deposition has been observed in many transect regions worldwide,from urban/agricultural areas to mountains.The Sichuan Basin(SCB),with 18 prefectural cities,is the most economically-developed region in western China,while the rural Qinghai-Tibetan Plateau(QTP)lies west of the SCB.Previous regional and national atmospheric modeling studies have sug-gested that large areas in the SCB-to-QTP transect region experience excessive deposition of sulfur and nitrogen.In this study,we applied a passive monitoring method at 11 sites(one in urban Chengdu and 10 from fivenature reserves)in this transect region from September 2021 to October 2022 to confirm the high sulfur and nitrogen deposition fluxes and to understand the gaps between the modeling and observation results for this transect region.These observations suggest that the five reserves are under eutrophication risk,and only two reserves are partially under acidification risk.Owing to the complex topography and landscapes,both sulfur and nitrogen deposition and critical loads exhibit large spatial variations within a reserve,such as Mount Emei.Regional atmospheric modeling may not accurately capture the spatial variations in deposition fluxes within a reserve;however,it can capture general spatial patterns over the entire transect.This study demonstrates that a combination of state-of-the-art atmospheric chemical models and low-cost monitoring methods is helpful for ecological risk assessments at a regional scale.展开更多
An improved Carnegie Ames Stanford Approach model （CASA model） was used to estimate the net primary productivity （NPP） of the Northeast China Transect （NECT） every month from 1982 to 2000. The spatial-temporal d...An improved Carnegie Ames Stanford Approach model （CASA model） was used to estimate the net primary productivity （NPP） of the Northeast China Transect （NECT） every month from 1982 to 2000. The spatial-temporal distribution of NPP along NECT and its response to climatic change were also analyzed. Results showed that the change tendency of NPP spatial distribution in NECT is quite similar to that of precipitation and their spatial correlation coefficient is up to 0.84 （P 〈 0.01）. The inter-annual variation of NPP in NECT is mainly affected by the change of the aestival NPP every year, which accounts for 67.6% of the inter-annual increase in NPP and their spatial correlation coefficient is 0.95 （P 〈 0.01）. The NPP in NECT is mainly cumulated between May and September, which accounts for 89.8% of the annual NPP. The NPP in summer （June to August） accounts for 65.9% of the annual NPP and is the lowest in winter. Recent climate changes have enhanced plant growth in NECT. The mean NPP increased 14.3% from 1980s to 1990s. The inter-annual linear trend of NPP is 4.6 gC·m^-2·a^-1, and the relative trend is 1.17%, which owns mainly to the increasing temperature.展开更多
The 16 tree species on Northeast China Transect (NECT) were analyzed from the change of geographical distribution, frequency and dominance pattern and the spatial correlation at landscape scale in 1986 and 1994. Pin...The 16 tree species on Northeast China Transect (NECT) were analyzed from the change of geographical distribution, frequency and dominance pattern and the spatial correlation at landscape scale in 1986 and 1994. Pinus koraiensis Sieb. et Zucc. and Fraxinus rhynchophylla Hemsl. had spread rapidly towards west and east, respectively. The frontier form of species had close relation with its movement. The patch size of Pinus koraiensis , Populus davidiana Dode., Phellodendron amurense Rupr., Juglans mandshurica Maxim., Fraxinus mandshurica Rupr., Betula dahurica Pall., Picea koraiensis Nakai, Abies nephrolepis Maxim. and Larix olgeusis var. koreana Nakai decreased, however, Quercus mongolica Fisch., Betula costata Trautv., Acer mono Maxim., Tilia spp., Ulmus spp., Betula platyphylla Suk. and Fraxinus rhynchophylla increased. The frequency pattern of Populus davidiana , Betula platyphylla , Fraxinus rhynchophylla and Betula dahurica changed significantly. The dominance pattern of Populus davidiana , Tilia spp., Juglans mandshurica , Betula platyphylla , Betula dahurica and Abies nephrolepis changed significantly. The spatial correlation between Quercus mongolica and Betula dahurica , Betula costata and Picea spp., Betula costata and Abies nephrolepis , Picea spp. and Abies nephrolepis declined, however, the spatial correlation between Larix spp. and Betula platyphylla , Acer mono and Ulmus spp. increased.展开更多
Net photosynthesis ( P n ), transpiration ( E ), stomatal conductance ( g s) and water use efficiency (WUE) of more than 218 species belonging to two different reproductive functional types, i.e. clonal (115 ...Net photosynthesis ( P n ), transpiration ( E ), stomatal conductance ( g s) and water use efficiency (WUE) of more than 218 species belonging to two different reproductive functional types, i.e. clonal (115 species) and non_clonal species (103 species), along the 1 670 km Northeast China Transect (NECT) were analyzed. The results showed that P n and WUE appeared to be lower in the east and west ends of NECT, with peaks in the middle. Transpiration was found to be higher in the west end, where most temperate desert species were distributed. On the same site, most clonal species showed higher P n and related physiological variables than non_clonal species. For different growth forms over NECT, e.g. forest trees, shrubs and grasses, meadow steppe shrubs and grasses, typical steppe shrubs and grasses, the meadow steppe and typical steppe grasses, showed higher values of physiological variables than the forest or the desert species. But for the two reproductive plant functional types (PFTs), clonal species had higher physiological variables, with averages of 22%, 15%, 23% and 14% higher than the non_clonal ones for P n , E, g s, and WUE, respectively. Such differences indicated that clonal species might have advantages over non_clonal species in utilizing environmental resources such as light, CO 2, and especially water.展开更多
Livelihoods of farmers and nomads in Tibetan Plateau are severely affected by grassland and herbal resources degeneration. How to help them achieve livelihood diversi- fication is a key sustainable development issue. ...Livelihoods of farmers and nomads in Tibetan Plateau are severely affected by grassland and herbal resources degeneration. How to help them achieve livelihood diversi- fication is a key sustainable development issue. This paper examines livelihood assets, live- lihood diversification level and livelihood strategies of farmers and nomads in 3 regions of eastern transect in Tibetan Plateau. The results show that livelihood diversification is a popular strategy. From high mountain gorge region to mountain plateau region and plateau region, livelihood diversification level is reduced, and livelihood activities and proportion of extended livelihood also decrease. Livelihood assets and livelihood diversification level decrease with the increase of elevation, mainly shown in human assets and natural assets. Livelihood diversification level is highly correlative with livelihood assets, mainly shown in natural assets, human assets and social assets. Livelihood improvement strategies of farmers and nomads are still based on existing livelihood assets, mainly raising livestock and digging herbs, and less farmers and nomads consider off-farm employment or doing business. Nomads in plateau region should learn much from experiences of extended livelihoods of people in high mountain gorge region and mountain plateau region. Therefore, aids of governments should focus on relieving restricted factors of livelihood diversification and help them improve their abilities to build up extended type livelihoods.展开更多
Our previous studies revealed that etomidate, a non-barbiturate intravenous anesthetic agent, has protective effects on retinal ganglion cells within 7 days after optic nerve transection. Whether this process is relat...Our previous studies revealed that etomidate, a non-barbiturate intravenous anesthetic agent, has protective effects on retinal ganglion cells within 7 days after optic nerve transection. Whether this process is related to anti-oxidative stress is not clear. To reveal its mechanism, we established the optic nerve transection injury model by transecting 1 mm behind the left eyeball of adult male Sprague-Dawley rats. The rats received an intraperitoneal injection of etomidate(4 mg/kg) once per day for 7 days. The results showed that etomidate significantly enhanced the number of retinal ganglion cells retrogradely labeled with Fluorogold at 7 days after optic nerve transection. Etomidate also significantly reduced the levels of nitric oxide and malonaldehyde in the retina and increased the level of glutathione at 12 hours after optic nerve transection. Thus, etomidate can protect retinal ganglion cells after optic nerve transection in adult rats by activating an anti-oxidative stress response. The study was approved by the Animal Ethics Committee at Air Force Medical University, China(approval No. 20180305) on March 5, 2018.展开更多
From July 2008 to August 2008, 72 leaf samples from 22 species and 81 soil samples in the nine natural forest ecosystems were collected, from north to south along the North-South Transect of Eastern China （NSTEC）. B...From July 2008 to August 2008, 72 leaf samples from 22 species and 81 soil samples in the nine natural forest ecosystems were collected, from north to south along the North-South Transect of Eastern China （NSTEC）. Based on these samples, we studied the geographical distribution patterns of vegetable water use efficiency （WUE） and nitrogen use efficiency （NUE）, and analyzed their relationship with environmental factors. The vegetable WUE and NUE were calculated through the measurement of foliar δ 13C and C/N of predominant species, respectively. The results showed： （1） vegetable WUE, ranging from 2.13 to 28.67 mg C g-1 H2O, increased linearly from south to north in the representative forest ecosystems along the NSTEC, while vegetable NUE showed an opposite trend, increasing from north to south, ranging from 12.92 to 29.60 g C g-1 N. （2） Vegetable WUE and NUE were dominantly driven by climate and significantly affected by soil nutrient factors. Based on multiple stepwise regression analysis, mean annual temperature, soil phosphorus concentration, and soil nitrogen concentration were responding for 75.5% of the variations of WUE （p0.001）. While, mean annual precipitation and soil phosphorus concentration could explain 65.7% of the change in vegetable NUE （p0.001）. Moreover, vegetable WUE and NUE would also be seriously influenced by atmospheric nitrogen deposition in nitrogen saturated ecosystems. （3） There was a significant trade-off relationship between vegetable WUE and NUE in the typical forest ecosystems along the NSTEC （p0.001）, indicating a balanced strategy for vegetation in resource utilization in natural forest ecosystems along the NSTEC. This study suggests that global change would impact the resource use efficiency of forest ecosystems. However, vegetation could adapt to those changes by increasing the use efficiency of shortage resource while decreasing the relatively ample one. But extreme impacts, such as heavy nitrogen deposition, would break this trade-off mechanism and give a dramatic disturbance to the ecosystem biogeochemical cycle.展开更多
Long non-coding RNAs(lncRNAs)are abundantly expressed in the central nervous system and exert a critical role in gene regulation via multiple biological processes.To uncover the functional significance and molecular m...Long non-coding RNAs(lncRNAs)are abundantly expressed in the central nervous system and exert a critical role in gene regulation via multiple biological processes.To uncover the functional significance and molecular mechanisms of lncRNAs in spinal cord injury(SCI),the expression signatures of lncRNAs were profiled using RNA sequencing(RNA-seq)technology in a Sprague-Dawley rat model of the 10th thoracic vertebra complete transection SCI.Results showed that 116 of 14,802 detected lncRNAs were differentially expressed,among which 16—including eight up-regulated(H19,Vof16,Hmox2-ps1,LOC100910973,Ybx1-ps3,Nnat,Gcgr,LOC680254)and eight down-regulated(Rmrp,Terc,Ngrn,Ppp2r2b,Cox6a2,Rpl37a-ps1,LOC360231,Rpph1)—demonstrated fold changes>2 in response to transection SCI.A subset of these RNA-seq results was validated by quantitative real-time PCR.The levels of 821 mRNAs were also significantly altered post-SCI;592 mRNAs were up-regulated and 229 mRNAs were down-regulated by more than 2-fold.Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)analyses showed that differentially expressed mRNAs were related to GO biological processes and molecular functions such as injury and inflammation response,wound repair,and apoptosis,and were significantly enriched in 15 KEGG pathways,including cell phagocytosis,tumor necrosis factor alpha pathway,and leukocyte migration.Our results reveal the expression profiles of lncRNAs and mRNAs in the rat spinal cord of a complete transection model,and these differentially expressed lncRNAs and mRNAs represent potential novel targets for SCI treatment.We suggest that lncRNAs may play an important role in the early immuno-inflammatory response after spinal cord injury.This study was approved by the Administration Committee of Experimental Animals,Guangdong Province,China.展开更多
AIM：To assess the expression of nestin and glial fibrillary acidic protein（GFAP）in rat retina after optic nerve transection.METHODS：Rats were randomly divided into normal control group,sham group and operation gro...AIM：To assess the expression of nestin and glial fibrillary acidic protein（GFAP）in rat retina after optic nerve transection.METHODS：Rats were randomly divided into normal control group,sham group and operation group,and used for establishing an animal model of optic nerve transection.Retinal specimen of each group was collected at 3,48h,7and 14d postoperative.Nestin and GFAP expressions on sagittal sections were analyzed by immunohistochemical staining,and protein extraction was analyzed by Western blot.RESULTS：Immunohistochemical analysis showed that nestin positive staining was rarely detected in normal control group and sham group,while sham group showed weak positive staining at 3h postoperative,the reaction gradually increased at 48h postoperative,and reached its maximum at 7d postoperative,and then decreased at 14d postoperative.Compared to the expression of GFAP,there was not statistically significant obvious difference among three groups（P〉0.05）.Result of Western blot method was consistent with that of immunohistochemical method.CONCLUSION：The expression of nestin increased in a time dependent fashion in Müller cells of retina following optic nerve transection,which was statistically significant,but there was no obvious difference in GFAP expression.The results indicate that an increase in colloid synthesis in retina following optic nerve transection can improve the retinal neurons’environment.展开更多
An abrupt ice and snow storm disaster which occurred in the spring of 2008 severely destroyed forests over a surprisingly large portion of southern China. A transect crossing Jinggang Mountain-Jitai Basin-Yushan Mount...An abrupt ice and snow storm disaster which occurred in the spring of 2008 severely destroyed forests over a surprisingly large portion of southern China. A transect crossing Jinggang Mountain-Jitai Basin-Yushan Mountain-Wuyi Mountain was selected as the study area. The authors integrated field data collected in two field surveys to analyze the impacts of the disturbance on forests. The following results were obtained. （1） The extent of damage to plantations along the transect decreased in the order of slash pine 〉 masson pine 〉 mixed plantation 〉 Chinese fir. Slash pine is an introduced species from southern America which is characterized by fast growth, low wood quality and rich oleoresin, and showed a damage rate of 61.3% of samples, of which 70.4% cannot recover naturally. Masson pine is the native pioneer species of forests with harder wood, and 52.5% were damaged due to turpentine, of which 60.9% cannot recovery naturally. Chinese fir is a local tree species and samples showed a rate of 46% and a relative rate of 32.5%, lower than the mixed plantation. （2） From west to east along the transect, we can see that evergreen broad-leaved forest of the western transect on Jinggang Mountain showed the lightest damage extent, and a Cryptomeria plantation at an altitude of 700 m was severely destroyed while Chinese fir showed light damage below 700 m and relatively severe damage above 900 m. Masson pine and slash pine in the central transect in Jitai Basin were damaged severely due to turpentine activities, and closed natural secondary deciduous broad-leaved forest was damaged severely due to high ice and snow accumulation on intertwined shrubs. Masson pine aerial-seeding plantations below 400 m along the eastern transect in Xingguo and Ningdu counties were nearly undamaged for small tree sizes, and Chinese fir at 500-900 m altitude showed a lighter damage extent. However, masson pine which was distributed above 400 m and planted in the 1960s, was severely damaged due to turpentine.展开更多
BACKGROUND： The hippocampus regulates the hypothalamic-pituitary-adrenal axis through negative feedback. The hypothalamic paraventricular nucleus receives neuronal input from the hippocampus via the fomix, OBJECTIVE...BACKGROUND： The hippocampus regulates the hypothalamic-pituitary-adrenal axis through negative feedback. The hypothalamic paraventricular nucleus receives neuronal input from the hippocampus via the fomix, OBJECTIVE： To explore whether the negative feedback effect of the hippocampus on the hypothalamic-pituitary-adrenal axis is contributed to the inhibitory effect of mineralocorticoid receptor （MR） and glucocorticoid receptor （GR） in the hippocampus on the paraventricular nucleus via the fornix. DESIGN, TIME AND SETTING： Randomized, controlled, animal experiment. The study was performed at the Department of Histology and Embryology, China Medical University between September 2006 and September 2008. MATERIALS： Rabbit anti-rat anti-MR and rabbit anti-rat anti-GR antibodies were purchased from Santa Cruz Biotechnology, USA. Rabbit anti-rat anti-corticotrophin releasing hormone （CRH） and rabbit anti-rat anti-arginine vasopressin antibodies were purchased from Wuhan Boster. METHODS： A total of 90 male, Wistar rats were randomly divided into model and sham-surgery groups （n = 45）. Fornix transection was performed in the model group, while the sham-surgery group underwent surgery, but no fornix transection. MAIN OUTCOME MEASURES： Immunohistochemistry was used to examine MR and GR expression in the hippocampus, as well as CRH and anti-arginine vasopressin in the paraventricular nucleus. Western blot was used to measure alterations in MR, GR, and CRH protein expression following fomix transection. RESULTS： Compared with the sham-surgery group, there were no obvious changes in MR and GR expression in the hippocampus, or CRH and anti-arginine vasopressin expression in the paraventdcular nucleus within 4 days of fornix transection. However, after 7-10 days, significantly decreased MR and GR expression in the hippocampus, and increased CRH and anti-arginine vasopmssin expression in the paraventricular nucleus were observed （P 〈 0.05-0.01）. CONCLUSION： Negative feedback from the hippocampus on the hypothalamic-pituitary-adrenal axis might be mediated through the fornix, and the corticosterene actions mediated by hippocampal corticosteroid receptors indirectly modulated the hypothalamic-pituitary-adrenal axis.展开更多
The authors analyzed the data collected in the Ecological Station Jiaozhou Bay from May 1991 to November 1994, including 12 seasonal investigations, to determine the characteristics, dynamic cycles and variation trend...The authors analyzed the data collected in the Ecological Station Jiaozhou Bay from May 1991 to November 1994, including 12 seasonal investigations, to determine the characteristics, dynamic cycles and variation trends of the silicate in the bay. The results indicated that the rivers around Jiaozhou Bay provided abundant supply of silicate to the bay. The silicate concentration there depended on river flow variation. The horizontal variation of silicate concentration on the transect showed that the silicate concentration decreased with distance from shorelines. The vertical variation of it showed that silicate sank and deposited on the sea bottom by phytoplankton uptake and death, and zooplankton excretion. In this way, silicon would endlessly be transferred from terrestrial sources to the sea bottom. The silicon took up by phytoplankton and by other biogeochemical processes led to insufficient silicon supply for phytoplankton growth. In this paper, a 2D dynamic model of river flow versus silicate concentration was established by which silicate concentrations of 0.028–0.062 μmol/L in seawater was yielded by inputting certain seasonal unit river flows (m3/s), or in other words, the silicate supply rate; and when the unit river flow was set to zero, meaning no river input, the silicate concentrations were between 0.05 –0.69 μmol/L in the bay. In terms of the silicate supply rate, Jiaozhou Bay was divided into three parts. The division shows a given river flow could generate several different silicon levels in corresponding regions, so as to the silicon-limitation levels to the phytoplankton in these regions. Another dynamic model of river flow versus primary production was set up by which the phytoplankton primary production of 5.21–15.55(mgC/m2·d)/(m3/s) were obtained in our case at unit river flow values via silicate concentration or primary production conversion rate. Similarly, the values of primary production of 121.98–195.33 (mgC/m2·d) were achieved at zero unit river flow condition. A primary production conversion rate reflects the sensitivity to silicon depletion so as to different phytoplankton primary production and silicon requirements by different phytoplankton assemblages in different marine areas. In addition, the authors differentiated two equations (Eqs.1 and 2) in the models to obtain the river flow variation that determines the silicate concentration variation, and in turn, the variation of primary production. These results proved further that nutrient silicon is a limiting factor for phytoplankton growth.展开更多
Comprehensive information on geographic patterns of leaf morphological traits in Chinese forests is still scarce.To explore the spatial patterns of leaf traits,we investigated leaf area(LA),leaf thickness(LT),specific...Comprehensive information on geographic patterns of leaf morphological traits in Chinese forests is still scarce.To explore the spatial patterns of leaf traits,we investigated leaf area(LA),leaf thickness(LT),specific leaf area(SLA),and leaf dry matter content(LDMC) across 847 species from nine typical forests along the North-South Transect of Eastern China(NSTEC) between July and August 2013,and also calculated the community weighted means(CWM) of leaf traits by determining the relative dominance of each species.Our results showed that,for all species,the means(± SE) of LA,LT,SLA,and LDMC were 2860.01 ± 135.37 mm2,0.17 ± 0.003 mm,20.15 ± 0.43 m2 kg–1,and 316.73 ± 3.81 mg g–1,respectively.Furthermore,latitudinal variation in leaf traits differed at the species and community levels.Generally,at the species level,SLA increased and LDMC decreased as latitude increased,whereas no clear latitudinal trends among LA or LT were found,which could be the result of shifts in plant functional types.When scaling up to the community level,more significant spatial patterns of leaf traits were observed(R2 = 0.46–0.71),driven by climate and soil N content.These results provided synthetic data compilation and analyses to better parameterize complex ecological models in the future,and emphasized the importance of scaling-up when studying the biogeographic patterns of plant traits.展开更多
OBJECTIVE： To evaluate the effects of olfactory ensheathing cell transplantation on functional recovery of rats with complete spinal cord transection. DATA SOURCES： A computer-based online search of Medline （1989-2...OBJECTIVE： To evaluate the effects of olfactory ensheathing cell transplantation on functional recovery of rats with complete spinal cord transection. DATA SOURCES： A computer-based online search of Medline （1989-2013）, Embase （1989- 2013）, Cochrane library （1989-2013）, Chinese Biomedical Literature Database （1989-2013）, China National Knowledge Infrastructure （1989-2013）, VIP （1989-2013）, Wanfang databases （1989-2013） and Chinese Clinical Trial Register was conducted to collect randomized controlled trial data regarding olfactory ensheathing cell transplantation for the treatment of complete spinal cord transection in rats. SELECTION CRITERIA： Randomized controlled trials investigating olfactory ensheathing cell transplantation and other transplantation methods for promoting neurological functional recov- ery of rats with complete spinal cord transection were included in the analysis. Meta analysis was conducted using RevMan 4.2.2 software. MAIN OUTCOME MEASURES： Basso, Beattie and Bresnahan scores of rats with complete spinal cord transection were evaluated in this study. RESULTS： Six randomized controlled trials with high quality methodology were included. Meta analysis showed that Basso, Beattie and Bresnahan scores were significantly higher in the olfacto- ry ensheathing cell transplantation group compared with the control group （WMD = 3.16, 95% （21 （1.68, 4.65）; P 〈 0.00001）. CONCLUSION： Experimental studies have shown that olfactory ensheathing cell transplantation can promote the functional recovery of motor nerves in rats with complete spinal cord transection.展开更多
We present n-alkane distributions in the soil samples along a transect from Lhasa on the Tibetan Plateau to Bharatpur in Nepal, which covers a large geographical area and a wide range of climatic conditions. These dat...We present n-alkane distributions in the soil samples along a transect from Lhasa on the Tibetan Plateau to Bharatpur in Nepal, which covers a large geographical area and a wide range of climatic conditions. These data allow us to assess the significance of n-alkane distributions in different vegetation types and their relationships to temperature and precipitation. In the tropical rainforest and broadleaved forest zones, n-alkanes exhibit a bimodal distribution pattern with dominant homologues around n-C_（31） and n-C_（23）. The bimodal distribution of tropical rainforest n-alkanes may be a general pattern because of the presence of many lianas, epiphytic plants, algae and the strong microbial activity and degradation involved in the postdepositional process. In the warm-temperate mixed forest and needle-leaved forest zones, the long-chain alkanes have a pattern of n-C_（31） n-C_（33） n-C_（27）. In the alpine shrub and grassland zone, although the most abundant homologue is n-C_（31） , relatively high n-C_（23） concentrations have also been observed in some samples. The statistical results show a good correlation between n-alkane proxies and climatic factors. The average chain length（ACL） values are positively correlated with precipitation and temperature across the transect. The carbon preference index（CPI） values show a negative correlation with temperature and precipitation along a Lhasa–Bharatpur transect. Although there is a positive relationship between ACL and temperature, it is difficult to separate the two climatic variables（temperature and precipitation） because they are well coupled in the monsoon region.展开更多
The East Eurasian Steppe Transect （EEST） is the ifrst international transect across regions of middle and high latitudes in the eastern Eurasian steppe. The EEST is an ideal platform for researching the response of ...The East Eurasian Steppe Transect （EEST） is the ifrst international transect across regions of middle and high latitudes in the eastern Eurasian steppe. The EEST is an ideal platform for researching the response of Eurasian temperate steppe to global change, because of its integrated gradients of temperature and human activities on a large-scale. In this study, basic characteristics of plant communities along the EEST across a latitudinal gradient was analyzed. According to the survey of 58 sampling sites, there are 140 species belonging to 34 families and 94 genera. Of particular note was the ifnding of Astragalus dalaiensis which has disappeared in the grasslands of China. On the whole, Gramineae plants are dominant with Liliaceae plants in the communities signiifcantly decreasing along the latitudinal gradient from south to north. The Shannon-Wiener index and biomass of communities all decreased along the latitudinal gradient with signiifcant negative linear regressions. The SDR2 （summed dominance ratio based on two factors） of dominant plants in the upper layers of communities, such as Stipa and Leymus chinensis, decreased along the latitudinal gradient from south to north. Especially, the SDR2 of L. chinensis decreased signiifcantly. The SDR2 of Cleistogenes squarrosa, Agropyron cristatum in the lower layers of communities and the indicator species for degradation were not affected. Potentilla acaulis was found mainly in the southern and northern areas. Stellera chamaejasme was found just in a few sites in the southern area of the EEST. In communities of Stipa grandis and Stipa krylovii, annual and biennial species are dominant. The ratio of annual and biennial species in the community is signiifcantly related to the latitudinal gradient. Perennial herbaceous plants and shrubs were not affected. According to the principal component analysis （PCA）, with the data from 58＆#215;140 dimensions, the ifrst and second components had the lowest proportion, thus indicating that the species compositions and community structures are homogeneous along the EEST. There is a certain degree of spatial differentiation along the EEST due to degradation’s differences resulting from the different land uses.展开更多
Percutaneous electrical nerve stimulation of an injured nerve can promote and accelerate peripheral nerve regeneration and improve function.When performing acupuncture and moxibustion,locating the injured nerve using ...Percutaneous electrical nerve stimulation of an injured nerve can promote and accelerate peripheral nerve regeneration and improve function.When performing acupuncture and moxibustion,locating the injured nerve using ultrasound before percutaneous nerve stimulation can help prevent further injury to an already injured nerve.However,stimulation parameters have not been standardized.In this study,we constructed a multi-layer human forearm model using finite element modeling.Taking current density and activated function as optimization indicators,the optimal percutaneous nerve stimulation parameters were established.The optimal parameters were parallel placement located 3 cm apart with the injury site at the midpoint between the needles.To validate the efficacy of this regimen,we performed a randomized controlled trial in 23 patients with median nerve transection who underwent neurorrhaphy.Patients who received conventional rehabilitation combined with percutaneous electrical nerve stimulation experienced greater improvement in sensory function,motor function,and grip strength than those who received conventional rehabilitation combined with transcutaneous electrical nerve stimulation.These findings suggest that the percutaneous electrical nerve stimulation regimen established in this study can improve global median nerve function in patients with median nerve transection.展开更多
Plant life form diversity and its direct gradient analysis on a larger scale climate change gradient were tested, based on the data from Northeast China Transect platform. The results showed that the species numbers, ...Plant life form diversity and its direct gradient analysis on a larger scale climate change gradient were tested, based on the data from Northeast China Transect platform. The results showed that the species numbers, life form richness and life form diversity were relative higher at the eastern forests and the ecotone between typical vegetation, while those on the meadow grasslands and typical steppes were lower. Although plant life forms can reflect the climate variations, life form diversity is not consistent with the major global gradient along the NECT.展开更多
基金supported by National Key R&D Program of China(2021YFA1101200)National Natural Science Foundation of China(82171048+6 种基金81800842)Key R&D Program of Zhejiang Province(2021C03065)Key R&D Program of Wenzhou Eye Hospital(YNZD1201902)Key R&D Program of Wenzhou(ZY2022021)R&D Program of Wenzhou(H20220008)Research Initiation Funds from Wenzhou Eye Hospital(KYQD20221203)China Postdoctoral Science Foundation(2023M742674)。
文摘In adult mammals,optic nerve injury leads to irreversible vision loss due to its extremely limited regenerative capacity.In contrast,adult zebrafish possess a robust capacity for spontaneous visual system regeneration,although the spatiotemporal coordination of recovery across the retina,optic nerve,and brain remains poorly understood.In the present study,the regenerative dynamics following optic nerve transection were systematically characterized in adult zebrafish over a 5 week period using hematoxylin-eosin staining,immunohistochemistry,transmission electron microscopy,single-cell RNA sequencing,and optokinetic response(OKR)behavioral assessments.At 1 week post-injury(1 wpi),retinal ganglion cell depletion was evident but showed significant recovery by 2 wpi.Concurrently,the injured optic nerve displayed a marked increase in diameter and cell number at 2 wpi,including widespread expression of proliferating cell nuclear antigen,consistent with heightened proliferative activity.Single-cell transcriptomic profiling at 2 wpi revealed five principal cell populations:fibroblasts,mural cells,immune cells,mature oligodendrocytes,and myelin-forming oligodendrocytes.By 4-5 wpi,remyelination within the optic nerve and re-establishment of synaptic architecture in the optic tectum were strongly correlated with functional restoration of OKR behavior.These findings provide a comprehensive spatiotemporal framework of visual pathway regeneration in zebrafish,establishing a valuable model for elucidating conserved mechanisms of neural repair with translational potential for human vision restoration.
基金supported by awards from the EPSRC Centre for Doctoral Training in Regenerative Medicine(EP/L014904/1,to JW)an NHS bursary(to RHB)an EPSRC Healthcare Technologies award(EP/T013885/1,to DMC)。
文摘Functional recovery in penetrating neurological injury is hampered by a lack of clinical regenerative therapies.Biomaterial therapies show promise as medical materials for neural repair through immunomodulation,structural support,and delivery of therapeutic biomolecules.However,a lack of facile and pathology-mimetic models for therapeutic testing is a bottleneck in neural tissue engineering research.We have deployed a two-dimensional,high-density multicellular cortical brain sheet to develop a facile model of injury(macrotransection/scratch wound)in vitro.The model encompasses the major neural cell types involved in pathological responses post-injury.Critically,we observed hallmark pathological responses in injury foci including cell scarring,immune cell infiltration,precursor cell migration,and shortrange axonal sprouting.Delivering test magnetic particles to evaluate the potential of the model for biomaterial screening shows a high uptake of introduced magnetic particles by injury-activated immune cells,mimicking in vivo findings.Finally,we proved it is feasible to create reproducible traumatic injuries in the brain sheet(in multielectrode array devices in situ)characterized by focal loss of electrical spiking in injury sites,offering the potential for longer term,electrophysiology plus histology assays.To our knowledge,this is the first in vitro simulation of transecting injury in a two-dimensional multicellular cortical brain cell sheet,that allows for combined histological and electrophysiological readouts of damage/repair.The patho-mimicry and adaptability of this simplified model of brain injury could benefit the testing of biomaterial therapeutics in regenerative neurology,with the option for functional electrophysiological readouts.
基金Under the auspices of National Natural Science Foundation of China(No.41929002)Science and Technology Department of Sichuan Province(No.2021YFS0338)。
文摘Enhanced sulfur and nitrogen deposition has been observed in many transect regions worldwide,from urban/agricultural areas to mountains.The Sichuan Basin(SCB),with 18 prefectural cities,is the most economically-developed region in western China,while the rural Qinghai-Tibetan Plateau(QTP)lies west of the SCB.Previous regional and national atmospheric modeling studies have sug-gested that large areas in the SCB-to-QTP transect region experience excessive deposition of sulfur and nitrogen.In this study,we applied a passive monitoring method at 11 sites(one in urban Chengdu and 10 from fivenature reserves)in this transect region from September 2021 to October 2022 to confirm the high sulfur and nitrogen deposition fluxes and to understand the gaps between the modeling and observation results for this transect region.These observations suggest that the five reserves are under eutrophication risk,and only two reserves are partially under acidification risk.Owing to the complex topography and landscapes,both sulfur and nitrogen deposition and critical loads exhibit large spatial variations within a reserve,such as Mount Emei.Regional atmospheric modeling may not accurately capture the spatial variations in deposition fluxes within a reserve;however,it can capture general spatial patterns over the entire transect.This study demonstrates that a combination of state-of-the-art atmospheric chemical models and low-cost monitoring methods is helpful for ecological risk assessments at a regional scale.
基金This paper was supported by the National Natural Sci-ence Foundation of China (Grant No. 40371001) and the Youth Foundation of Beijing Normal University
文摘An improved Carnegie Ames Stanford Approach model （CASA model） was used to estimate the net primary productivity （NPP） of the Northeast China Transect （NECT） every month from 1982 to 2000. The spatial-temporal distribution of NPP along NECT and its response to climatic change were also analyzed. Results showed that the change tendency of NPP spatial distribution in NECT is quite similar to that of precipitation and their spatial correlation coefficient is up to 0.84 （P 〈 0.01）. The inter-annual variation of NPP in NECT is mainly affected by the change of the aestival NPP every year, which accounts for 67.6% of the inter-annual increase in NPP and their spatial correlation coefficient is 0.95 （P 〈 0.01）. The NPP in NECT is mainly cumulated between May and September, which accounts for 89.8% of the annual NPP. The NPP in summer （June to August） accounts for 65.9% of the annual NPP and is the lowest in winter. Recent climate changes have enhanced plant growth in NECT. The mean NPP increased 14.3% from 1980s to 1990s. The inter-annual linear trend of NPP is 4.6 gC·m^-2·a^-1, and the relative trend is 1.17%, which owns mainly to the increasing temperature.
文摘The 16 tree species on Northeast China Transect (NECT) were analyzed from the change of geographical distribution, frequency and dominance pattern and the spatial correlation at landscape scale in 1986 and 1994. Pinus koraiensis Sieb. et Zucc. and Fraxinus rhynchophylla Hemsl. had spread rapidly towards west and east, respectively. The frontier form of species had close relation with its movement. The patch size of Pinus koraiensis , Populus davidiana Dode., Phellodendron amurense Rupr., Juglans mandshurica Maxim., Fraxinus mandshurica Rupr., Betula dahurica Pall., Picea koraiensis Nakai, Abies nephrolepis Maxim. and Larix olgeusis var. koreana Nakai decreased, however, Quercus mongolica Fisch., Betula costata Trautv., Acer mono Maxim., Tilia spp., Ulmus spp., Betula platyphylla Suk. and Fraxinus rhynchophylla increased. The frequency pattern of Populus davidiana , Betula platyphylla , Fraxinus rhynchophylla and Betula dahurica changed significantly. The dominance pattern of Populus davidiana , Tilia spp., Juglans mandshurica , Betula platyphylla , Betula dahurica and Abies nephrolepis changed significantly. The spatial correlation between Quercus mongolica and Betula dahurica , Betula costata and Picea spp., Betula costata and Abies nephrolepis , Picea spp. and Abies nephrolepis declined, however, the spatial correlation between Larix spp. and Betula platyphylla , Acer mono and Ulmus spp. increased.
文摘Net photosynthesis ( P n ), transpiration ( E ), stomatal conductance ( g s) and water use efficiency (WUE) of more than 218 species belonging to two different reproductive functional types, i.e. clonal (115 species) and non_clonal species (103 species), along the 1 670 km Northeast China Transect (NECT) were analyzed. The results showed that P n and WUE appeared to be lower in the east and west ends of NECT, with peaks in the middle. Transpiration was found to be higher in the west end, where most temperate desert species were distributed. On the same site, most clonal species showed higher P n and related physiological variables than non_clonal species. For different growth forms over NECT, e.g. forest trees, shrubs and grasses, meadow steppe shrubs and grasses, typical steppe shrubs and grasses, the meadow steppe and typical steppe grasses, showed higher values of physiological variables than the forest or the desert species. But for the two reproductive plant functional types (PFTs), clonal species had higher physiological variables, with averages of 22%, 15%, 23% and 14% higher than the non_clonal ones for P n , E, g s, and WUE, respectively. Such differences indicated that clonal species might have advantages over non_clonal species in utilizing environmental resources such as light, CO 2, and especially water.
基金The National Basic Research Program of China, No.2005CB422006 National Natural Science Foundation of China, No.40601006
文摘Livelihoods of farmers and nomads in Tibetan Plateau are severely affected by grassland and herbal resources degeneration. How to help them achieve livelihood diversi- fication is a key sustainable development issue. This paper examines livelihood assets, live- lihood diversification level and livelihood strategies of farmers and nomads in 3 regions of eastern transect in Tibetan Plateau. The results show that livelihood diversification is a popular strategy. From high mountain gorge region to mountain plateau region and plateau region, livelihood diversification level is reduced, and livelihood activities and proportion of extended livelihood also decrease. Livelihood assets and livelihood diversification level decrease with the increase of elevation, mainly shown in human assets and natural assets. Livelihood diversification level is highly correlative with livelihood assets, mainly shown in natural assets, human assets and social assets. Livelihood improvement strategies of farmers and nomads are still based on existing livelihood assets, mainly raising livestock and digging herbs, and less farmers and nomads consider off-farm employment or doing business. Nomads in plateau region should learn much from experiences of extended livelihoods of people in high mountain gorge region and mountain plateau region. Therefore, aids of governments should focus on relieving restricted factors of livelihood diversification and help them improve their abilities to build up extended type livelihoods.
基金supported by the National Natural Science Foundation of China,No.81670846(to MMW)and 81470631(to SWY)the Natural Science Foundation of Shaanxi Province of China,No.2016SF-171(to MMW)the National Basic Research Program of China,No.2014CB542202(to SWY)
文摘Our previous studies revealed that etomidate, a non-barbiturate intravenous anesthetic agent, has protective effects on retinal ganglion cells within 7 days after optic nerve transection. Whether this process is related to anti-oxidative stress is not clear. To reveal its mechanism, we established the optic nerve transection injury model by transecting 1 mm behind the left eyeball of adult male Sprague-Dawley rats. The rats received an intraperitoneal injection of etomidate(4 mg/kg) once per day for 7 days. The results showed that etomidate significantly enhanced the number of retinal ganglion cells retrogradely labeled with Fluorogold at 7 days after optic nerve transection. Etomidate also significantly reduced the levels of nitric oxide and malonaldehyde in the retina and increased the level of glutathione at 12 hours after optic nerve transection. Thus, etomidate can protect retinal ganglion cells after optic nerve transection in adult rats by activating an anti-oxidative stress response. The study was approved by the Animal Ethics Committee at Air Force Medical University, China(approval No. 20180305) on March 5, 2018.
基金National Natural Science Foundation of China No.30590381 No.31000211 National Basic Research Program of China No.2010CB833504
文摘From July 2008 to August 2008, 72 leaf samples from 22 species and 81 soil samples in the nine natural forest ecosystems were collected, from north to south along the North-South Transect of Eastern China （NSTEC）. Based on these samples, we studied the geographical distribution patterns of vegetable water use efficiency （WUE） and nitrogen use efficiency （NUE）, and analyzed their relationship with environmental factors. The vegetable WUE and NUE were calculated through the measurement of foliar δ 13C and C/N of predominant species, respectively. The results showed： （1） vegetable WUE, ranging from 2.13 to 28.67 mg C g-1 H2O, increased linearly from south to north in the representative forest ecosystems along the NSTEC, while vegetable NUE showed an opposite trend, increasing from north to south, ranging from 12.92 to 29.60 g C g-1 N. （2） Vegetable WUE and NUE were dominantly driven by climate and significantly affected by soil nutrient factors. Based on multiple stepwise regression analysis, mean annual temperature, soil phosphorus concentration, and soil nitrogen concentration were responding for 75.5% of the variations of WUE （p0.001）. While, mean annual precipitation and soil phosphorus concentration could explain 65.7% of the change in vegetable NUE （p0.001）. Moreover, vegetable WUE and NUE would also be seriously influenced by atmospheric nitrogen deposition in nitrogen saturated ecosystems. （3） There was a significant trade-off relationship between vegetable WUE and NUE in the typical forest ecosystems along the NSTEC （p0.001）, indicating a balanced strategy for vegetation in resource utilization in natural forest ecosystems along the NSTEC. This study suggests that global change would impact the resource use efficiency of forest ecosystems. However, vegetation could adapt to those changes by increasing the use efficiency of shortage resource while decreasing the relatively ample one. But extreme impacts, such as heavy nitrogen deposition, would break this trade-off mechanism and give a dramatic disturbance to the ecosystem biogeochemical cycle.
基金financially supported by the National Natural Science Foundation of China,No.81371366(to HFW)Characteristic Innovation Project of Colleges and Universities in Guangdong Province of China,No.2018KTSCX075(to HFW)+3 种基金the Key Project of Social Development of Dongguan of China,No.20185071521640(to HFW)College Students’ Science and Technology Innovation Training Project,China,Nos.201810571058,GDMU2018024,GDMU2018056,GDMU2018061(to HFW)College Students’ Innovative Experimental Project in Guangdong Medical University,China,No.ZZDS001(to HFW)College Students’ Science and Technology Innovation Cultivation Project in Guangdong of China,No.pdjh2019b0217(to HFW)
文摘Long non-coding RNAs(lncRNAs)are abundantly expressed in the central nervous system and exert a critical role in gene regulation via multiple biological processes.To uncover the functional significance and molecular mechanisms of lncRNAs in spinal cord injury(SCI),the expression signatures of lncRNAs were profiled using RNA sequencing(RNA-seq)technology in a Sprague-Dawley rat model of the 10th thoracic vertebra complete transection SCI.Results showed that 116 of 14,802 detected lncRNAs were differentially expressed,among which 16—including eight up-regulated(H19,Vof16,Hmox2-ps1,LOC100910973,Ybx1-ps3,Nnat,Gcgr,LOC680254)and eight down-regulated(Rmrp,Terc,Ngrn,Ppp2r2b,Cox6a2,Rpl37a-ps1,LOC360231,Rpph1)—demonstrated fold changes>2 in response to transection SCI.A subset of these RNA-seq results was validated by quantitative real-time PCR.The levels of 821 mRNAs were also significantly altered post-SCI;592 mRNAs were up-regulated and 229 mRNAs were down-regulated by more than 2-fold.Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)analyses showed that differentially expressed mRNAs were related to GO biological processes and molecular functions such as injury and inflammation response,wound repair,and apoptosis,and were significantly enriched in 15 KEGG pathways,including cell phagocytosis,tumor necrosis factor alpha pathway,and leukocyte migration.Our results reveal the expression profiles of lncRNAs and mRNAs in the rat spinal cord of a complete transection model,and these differentially expressed lncRNAs and mRNAs represent potential novel targets for SCI treatment.We suggest that lncRNAs may play an important role in the early immuno-inflammatory response after spinal cord injury.This study was approved by the Administration Committee of Experimental Animals,Guangdong Province,China.
基金Supported by Special Scientific Research Program of Shaanxi Provincial Education Department(No.16JK1665)
文摘AIM：To assess the expression of nestin and glial fibrillary acidic protein（GFAP）in rat retina after optic nerve transection.METHODS：Rats were randomly divided into normal control group,sham group and operation group,and used for establishing an animal model of optic nerve transection.Retinal specimen of each group was collected at 3,48h,7and 14d postoperative.Nestin and GFAP expressions on sagittal sections were analyzed by immunohistochemical staining,and protein extraction was analyzed by Western blot.RESULTS：Immunohistochemical analysis showed that nestin positive staining was rarely detected in normal control group and sham group,while sham group showed weak positive staining at 3h postoperative,the reaction gradually increased at 48h postoperative,and reached its maximum at 7d postoperative,and then decreased at 14d postoperative.Compared to the expression of GFAP,there was not statistically significant obvious difference among three groups（P〉0.05）.Result of Western blot method was consistent with that of immunohistochemical method.CONCLUSION：The expression of nestin increased in a time dependent fashion in Müller cells of retina following optic nerve transection,which was statistically significant,but there was no obvious difference in GFAP expression.The results indicate that an increase in colloid synthesis in retina following optic nerve transection can improve the retinal neurons’environment.
基金National Natural Science Foundation of China, No.40971281 International Science and Technology Cooperative Program of China, No.2006DFB91920 National Key Project of Scientific and Technical Supporting Programs, No.2006BAC08B00 Acknowledgments We express our thanks to Mr. Fan Zhewen, who is the director of the Remote Sensing Center of Jiangxi province, and Mr. Qiu Zuozhen, who is the director of the Mountain-River-Lake Office of Ji＇an City, for their help in the field investigation, and Prof. Wang Hongqing for logistic support. We also gratefully acknowledge the local governments of Jinggangshan City, Taihe County, Xingguo County and Ningdu County, especially Mr. Tang Xiongjie and Ms. He Qingping, for facilitating the field survey and data collection.
文摘An abrupt ice and snow storm disaster which occurred in the spring of 2008 severely destroyed forests over a surprisingly large portion of southern China. A transect crossing Jinggang Mountain-Jitai Basin-Yushan Mountain-Wuyi Mountain was selected as the study area. The authors integrated field data collected in two field surveys to analyze the impacts of the disturbance on forests. The following results were obtained. （1） The extent of damage to plantations along the transect decreased in the order of slash pine 〉 masson pine 〉 mixed plantation 〉 Chinese fir. Slash pine is an introduced species from southern America which is characterized by fast growth, low wood quality and rich oleoresin, and showed a damage rate of 61.3% of samples, of which 70.4% cannot recover naturally. Masson pine is the native pioneer species of forests with harder wood, and 52.5% were damaged due to turpentine, of which 60.9% cannot recovery naturally. Chinese fir is a local tree species and samples showed a rate of 46% and a relative rate of 32.5%, lower than the mixed plantation. （2） From west to east along the transect, we can see that evergreen broad-leaved forest of the western transect on Jinggang Mountain showed the lightest damage extent, and a Cryptomeria plantation at an altitude of 700 m was severely destroyed while Chinese fir showed light damage below 700 m and relatively severe damage above 900 m. Masson pine and slash pine in the central transect in Jitai Basin were damaged severely due to turpentine activities, and closed natural secondary deciduous broad-leaved forest was damaged severely due to high ice and snow accumulation on intertwined shrubs. Masson pine aerial-seeding plantations below 400 m along the eastern transect in Xingguo and Ningdu counties were nearly undamaged for small tree sizes, and Chinese fir at 500-900 m altitude showed a lighter damage extent. However, masson pine which was distributed above 400 m and planted in the 1960s, was severely damaged due to turpentine.
基金the Postdoctoral Science Foundation of China,No. 20060390301the National Natural Science Foundation of China,No.30600341the Ph.D.Program Foundation of Ministry of Education of China,No.20050159011
文摘BACKGROUND： The hippocampus regulates the hypothalamic-pituitary-adrenal axis through negative feedback. The hypothalamic paraventricular nucleus receives neuronal input from the hippocampus via the fomix, OBJECTIVE： To explore whether the negative feedback effect of the hippocampus on the hypothalamic-pituitary-adrenal axis is contributed to the inhibitory effect of mineralocorticoid receptor （MR） and glucocorticoid receptor （GR） in the hippocampus on the paraventricular nucleus via the fornix. DESIGN, TIME AND SETTING： Randomized, controlled, animal experiment. The study was performed at the Department of Histology and Embryology, China Medical University between September 2006 and September 2008. MATERIALS： Rabbit anti-rat anti-MR and rabbit anti-rat anti-GR antibodies were purchased from Santa Cruz Biotechnology, USA. Rabbit anti-rat anti-corticotrophin releasing hormone （CRH） and rabbit anti-rat anti-arginine vasopressin antibodies were purchased from Wuhan Boster. METHODS： A total of 90 male, Wistar rats were randomly divided into model and sham-surgery groups （n = 45）. Fornix transection was performed in the model group, while the sham-surgery group underwent surgery, but no fornix transection. MAIN OUTCOME MEASURES： Immunohistochemistry was used to examine MR and GR expression in the hippocampus, as well as CRH and anti-arginine vasopressin in the paraventricular nucleus. Western blot was used to measure alterations in MR, GR, and CRH protein expression following fomix transection. RESULTS： Compared with the sham-surgery group, there were no obvious changes in MR and GR expression in the hippocampus, or CRH and anti-arginine vasopressin expression in the paraventdcular nucleus within 4 days of fornix transection. However, after 7-10 days, significantly decreased MR and GR expression in the hippocampus, and increased CRH and anti-arginine vasopmssin expression in the paraventricular nucleus were observed （P 〈 0.05-0.01）. CONCLUSION： Negative feedback from the hippocampus on the hypothalamic-pituitary-adrenal axis might be mediated through the fornix, and the corticosterene actions mediated by hippocampal corticosteroid receptors indirectly modulated the hypothalamic-pituitary-adrenal axis.
基金This study was funded by NSFC (No. 40036010), and the Director’s Fund of the Beihai Sea Monitoring Center, the State Oceanic Administration.
文摘The authors analyzed the data collected in the Ecological Station Jiaozhou Bay from May 1991 to November 1994, including 12 seasonal investigations, to determine the characteristics, dynamic cycles and variation trends of the silicate in the bay. The results indicated that the rivers around Jiaozhou Bay provided abundant supply of silicate to the bay. The silicate concentration there depended on river flow variation. The horizontal variation of silicate concentration on the transect showed that the silicate concentration decreased with distance from shorelines. The vertical variation of it showed that silicate sank and deposited on the sea bottom by phytoplankton uptake and death, and zooplankton excretion. In this way, silicon would endlessly be transferred from terrestrial sources to the sea bottom. The silicon took up by phytoplankton and by other biogeochemical processes led to insufficient silicon supply for phytoplankton growth. In this paper, a 2D dynamic model of river flow versus silicate concentration was established by which silicate concentrations of 0.028–0.062 μmol/L in seawater was yielded by inputting certain seasonal unit river flows (m3/s), or in other words, the silicate supply rate; and when the unit river flow was set to zero, meaning no river input, the silicate concentrations were between 0.05 –0.69 μmol/L in the bay. In terms of the silicate supply rate, Jiaozhou Bay was divided into three parts. The division shows a given river flow could generate several different silicon levels in corresponding regions, so as to the silicon-limitation levels to the phytoplankton in these regions. Another dynamic model of river flow versus primary production was set up by which the phytoplankton primary production of 5.21–15.55(mgC/m2·d)/(m3/s) were obtained in our case at unit river flow values via silicate concentration or primary production conversion rate. Similarly, the values of primary production of 121.98–195.33 (mgC/m2·d) were achieved at zero unit river flow condition. A primary production conversion rate reflects the sensitivity to silicon depletion so as to different phytoplankton primary production and silicon requirements by different phytoplankton assemblages in different marine areas. In addition, the authors differentiated two equations (Eqs.1 and 2) in the models to obtain the river flow variation that determines the silicate concentration variation, and in turn, the variation of primary production. These results proved further that nutrient silicon is a limiting factor for phytoplankton growth.
基金National Natural Science Foundation of China,No.31290221,No.31470506Chinese Academy of Sciences Strategic Priority Research Program,No.XDA05050702Program for Kezhen Distinguished Talents in Institute of Geographic Sciences and Natural Resources Research,CAS,No.2013RC102
文摘Comprehensive information on geographic patterns of leaf morphological traits in Chinese forests is still scarce.To explore the spatial patterns of leaf traits,we investigated leaf area(LA),leaf thickness(LT),specific leaf area(SLA),and leaf dry matter content(LDMC) across 847 species from nine typical forests along the North-South Transect of Eastern China(NSTEC) between July and August 2013,and also calculated the community weighted means(CWM) of leaf traits by determining the relative dominance of each species.Our results showed that,for all species,the means(± SE) of LA,LT,SLA,and LDMC were 2860.01 ± 135.37 mm2,0.17 ± 0.003 mm,20.15 ± 0.43 m2 kg–1,and 316.73 ± 3.81 mg g–1,respectively.Furthermore,latitudinal variation in leaf traits differed at the species and community levels.Generally,at the species level,SLA increased and LDMC decreased as latitude increased,whereas no clear latitudinal trends among LA or LT were found,which could be the result of shifts in plant functional types.When scaling up to the community level,more significant spatial patterns of leaf traits were observed(R2 = 0.46–0.71),driven by climate and soil N content.These results provided synthetic data compilation and analyses to better parameterize complex ecological models in the future,and emphasized the importance of scaling-up when studying the biogeographic patterns of plant traits.
文摘OBJECTIVE： To evaluate the effects of olfactory ensheathing cell transplantation on functional recovery of rats with complete spinal cord transection. DATA SOURCES： A computer-based online search of Medline （1989-2013）, Embase （1989- 2013）, Cochrane library （1989-2013）, Chinese Biomedical Literature Database （1989-2013）, China National Knowledge Infrastructure （1989-2013）, VIP （1989-2013）, Wanfang databases （1989-2013） and Chinese Clinical Trial Register was conducted to collect randomized controlled trial data regarding olfactory ensheathing cell transplantation for the treatment of complete spinal cord transection in rats. SELECTION CRITERIA： Randomized controlled trials investigating olfactory ensheathing cell transplantation and other transplantation methods for promoting neurological functional recov- ery of rats with complete spinal cord transection were included in the analysis. Meta analysis was conducted using RevMan 4.2.2 software. MAIN OUTCOME MEASURES： Basso, Beattie and Bresnahan scores of rats with complete spinal cord transection were evaluated in this study. RESULTS： Six randomized controlled trials with high quality methodology were included. Meta analysis showed that Basso, Beattie and Bresnahan scores were significantly higher in the olfacto- ry ensheathing cell transplantation group compared with the control group （WMD = 3.16, 95% （21 （1.68, 4.65）; P 〈 0.00001）. CONCLUSION： Experimental studies have shown that olfactory ensheathing cell transplantation can promote the functional recovery of motor nerves in rats with complete spinal cord transection.
基金supported by the National Natural Science Foundation of China(Grant nos.41302141 and 41272198)the Geological Research Program of China Geological Survey(No.12120113015400)
文摘We present n-alkane distributions in the soil samples along a transect from Lhasa on the Tibetan Plateau to Bharatpur in Nepal, which covers a large geographical area and a wide range of climatic conditions. These data allow us to assess the significance of n-alkane distributions in different vegetation types and their relationships to temperature and precipitation. In the tropical rainforest and broadleaved forest zones, n-alkanes exhibit a bimodal distribution pattern with dominant homologues around n-C_（31） and n-C_（23）. The bimodal distribution of tropical rainforest n-alkanes may be a general pattern because of the presence of many lianas, epiphytic plants, algae and the strong microbial activity and degradation involved in the postdepositional process. In the warm-temperate mixed forest and needle-leaved forest zones, the long-chain alkanes have a pattern of n-C_（31） n-C_（33） n-C_（27）. In the alpine shrub and grassland zone, although the most abundant homologue is n-C_（31） , relatively high n-C_（23） concentrations have also been observed in some samples. The statistical results show a good correlation between n-alkane proxies and climatic factors. The average chain length（ACL） values are positively correlated with precipitation and temperature across the transect. The carbon preference index（CPI） values show a negative correlation with temperature and precipitation along a Lhasa–Bharatpur transect. Although there is a positive relationship between ACL and temperature, it is difficult to separate the two climatic variables（temperature and precipitation） because they are well coupled in the monsoon region.
基金funded by the International Science & Technology Cooperation Program of China (2013DFR30760)the National Key Basic Research Program of China (2014CB138806)
文摘The East Eurasian Steppe Transect （EEST） is the ifrst international transect across regions of middle and high latitudes in the eastern Eurasian steppe. The EEST is an ideal platform for researching the response of Eurasian temperate steppe to global change, because of its integrated gradients of temperature and human activities on a large-scale. In this study, basic characteristics of plant communities along the EEST across a latitudinal gradient was analyzed. According to the survey of 58 sampling sites, there are 140 species belonging to 34 families and 94 genera. Of particular note was the ifnding of Astragalus dalaiensis which has disappeared in the grasslands of China. On the whole, Gramineae plants are dominant with Liliaceae plants in the communities signiifcantly decreasing along the latitudinal gradient from south to north. The Shannon-Wiener index and biomass of communities all decreased along the latitudinal gradient with signiifcant negative linear regressions. The SDR2 （summed dominance ratio based on two factors） of dominant plants in the upper layers of communities, such as Stipa and Leymus chinensis, decreased along the latitudinal gradient from south to north. Especially, the SDR2 of L. chinensis decreased signiifcantly. The SDR2 of Cleistogenes squarrosa, Agropyron cristatum in the lower layers of communities and the indicator species for degradation were not affected. Potentilla acaulis was found mainly in the southern and northern areas. Stellera chamaejasme was found just in a few sites in the southern area of the EEST. In communities of Stipa grandis and Stipa krylovii, annual and biennial species are dominant. The ratio of annual and biennial species in the community is signiifcantly related to the latitudinal gradient. Perennial herbaceous plants and shrubs were not affected. According to the principal component analysis （PCA）, with the data from 58＆#215;140 dimensions, the ifrst and second components had the lowest proportion, thus indicating that the species compositions and community structures are homogeneous along the EEST. There is a certain degree of spatial differentiation along the EEST due to degradation’s differences resulting from the different land uses.
基金supported by the National Natural Science Foundation of China,No.81801787(to XZS)China Postdoctoral Science Foundation,No.2018M640238(to XZS)the Natural Science Foundation of Tianjin,No.20JCQNJC01690(to XLC)。
文摘Percutaneous electrical nerve stimulation of an injured nerve can promote and accelerate peripheral nerve regeneration and improve function.When performing acupuncture and moxibustion,locating the injured nerve using ultrasound before percutaneous nerve stimulation can help prevent further injury to an already injured nerve.However,stimulation parameters have not been standardized.In this study,we constructed a multi-layer human forearm model using finite element modeling.Taking current density and activated function as optimization indicators,the optimal percutaneous nerve stimulation parameters were established.The optimal parameters were parallel placement located 3 cm apart with the injury site at the midpoint between the needles.To validate the efficacy of this regimen,we performed a randomized controlled trial in 23 patients with median nerve transection who underwent neurorrhaphy.Patients who received conventional rehabilitation combined with percutaneous electrical nerve stimulation experienced greater improvement in sensory function,motor function,and grip strength than those who received conventional rehabilitation combined with transcutaneous electrical nerve stimulation.These findings suggest that the percutaneous electrical nerve stimulation regimen established in this study can improve global median nerve function in patients with median nerve transection.
文摘Plant life form diversity and its direct gradient analysis on a larger scale climate change gradient were tested, based on the data from Northeast China Transect platform. The results showed that the species numbers, life form richness and life form diversity were relative higher at the eastern forests and the ecotone between typical vegetation, while those on the meadow grasslands and typical steppes were lower. Although plant life forms can reflect the climate variations, life form diversity is not consistent with the major global gradient along the NECT.
