Background: Understanding the role of species identity in interactions among individuals is crucial for assessing the productivity and stability of mixed forests over time. However, there is limited knowledge concerni...Background: Understanding the role of species identity in interactions among individuals is crucial for assessing the productivity and stability of mixed forests over time. However, there is limited knowledge concerning the variation in competitive effect and response of different species along climatic gradients. In this study, we investigated the importance of climate, tree size, and competition on the growth of three tree species: spruce(Picea abies), fir(Abies alba), and beech(Fagus sylvatica), and examined their competitive response and effect along a climatic gradient.Methods: We selected 39 plots distributed across the European mountains with records of the position and growth of 5,759 individuals. For each target species, models relating tree growth to tree size, climate and competition were proposed. Competition was modelled using a neighbourhood competition index that considered the effects of inter-and intraspecific competition on target trees. Competitive responses and effects were related to climate.Likelihood methods and information theory were used to select the best model.Results: Our findings revealed that competition had a greater impact on target species growth than tree size or climate. Climate did influence the competitive effects of neighbouring species, but it did not affect the target species? response to competition. The strength of competitive effects varied along the gradient, contingent on the identity of the interacting species. When the target species exhibited an intermediate competitive effect relative to neighbouring species, both higher inter-than intraspecific competitive effects and competition reduction occurred along the gradient. Notably, species competitive effects were most pronounced when the target species' growth was at its peak and weakest when growing conditions were far from their maximum.Conclusions: Climate modulates the effects of competition from neighbouring trees on the target tree and not the susceptibility of the target tree to competition. The modelling approach should be useful in future research to expand our knowledge of how competition modulates forest communities across environmental gradients.展开更多
Filtration has been widely used in re-circulating aquaculture system to remove waste. However, the study of some agricultural residues （corn） usage as the filter medium has not yet been studied. Therefore, the aim o...Filtration has been widely used in re-circulating aquaculture system to remove waste. However, the study of some agricultural residues （corn） usage as the filter medium has not yet been studied. Therefore, the aim of this study is to construct a filter made from inexpensive and readily available corn residues and to analyze its effectiveness in controlling suspended solids that directly impact health of fish through abrasion of gill tissues or indirectly through water quality deterioration. The performance evaluation procedure was carried out in an aquaculture system with production in glass tanks located indoor in laboratory at Faculty of Agriculture, Damietta University, Egypt. The evaluation included three concentrations of total suspended solids （450, 900 and 1,350 mg/L）; four residues particle size distribution （3.35, 9.53, 12.7 mm and ascending order to mentioned sizes from bottom to top）; and four thicknesses of filter layer （9, 21, 33 and 45 cm）. The effectiveness of this filter was measured by determining filter efficiency （ηf）, % and filtration rate （FR）, mL/min. It was observed that the maximum value of （ηf）, % was achieved at 450 mg/L concentration of total suspended solids, ascending order to sizes from bottom to top and 45 cm thickness of filtration layer. The maximum value of filtration rate was achieved at 450 mg/l concentration of total suspended solids, 12.7 mm particle size distribution and 9 cm thickness of filter layer. Results indicated that this filter is efficient enough to remove suspended solids. Therefore, this milled corn residues filter can be used in aquaculture systems for Nile tilapia, Oreochromis niloticus culture system.展开更多
With seeds of Caragana versicolor in Purang County,Xizang as the materials,the seed germination and seedling growth of C.versicolor were measured under acid and alkali stress,and the soil acidity and alkalinity for no...With seeds of Caragana versicolor in Purang County,Xizang as the materials,the seed germination and seedling growth of C.versicolor were measured under acid and alkali stress,and the soil acidity and alkalinity for normal growth and development of C.versicolor were determined,so as to provide the theoretical basis for cultivation of C.versicolor in acidified or alkaline soil.The results showed that the seed germination of C.versicolor was promoted when treated by strong acid(pH 3)and strong alkali(pH 11)solutions,and the seedling effect was good.The results also indicated that C.versicolor was a kind of plant with strong acid and alkali resistance,suitable for cultivation in acid and alkali soil areas.展开更多
The research aimed to analyze changes in photosynthetic characteristics of Paeonia ludlowii under saline-alkali stress,and annual seedlings of P.ludlowii were taken as the materials.Photoresponse process of P.ludlowii...The research aimed to analyze changes in photosynthetic characteristics of Paeonia ludlowii under saline-alkali stress,and annual seedlings of P.ludlowii were taken as the materials.Photoresponse process of P.ludlowii leaves under saline-alkali stress was simulated,and different models were used to fit photoresponse curve.The results showed that P n of P.ludlowii leaves showed the trend of first rising and then declining with PAR increased under saline-alkali stress;both G s and T r showed a rising trend with PAR increased;C i showed the trend of first declining and then rising with PAR increased.Photoresponse curve fitted by modified rectangular hyperbolic model had the best effect,and it was the optimal fitting model.P.ludlowii could adapt to saline-alkali stress in lower concentration,showing that P.ludlowii could be introduced and cultivated in saline-alkali land at a lower level.展开更多
This research article introduces and explores the concept of a hybrid prism, which combines the properties of a lens and a reflective prism, designed for optical systems that operate in different spectral ranges of el...This research article introduces and explores the concept of a hybrid prism, which combines the properties of a lens and a reflective prism, designed for optical systems that operate in different spectral ranges of electromagnetic waves. The hybrid prism allows for precise focusing of light rays in a glass body and X-rays in a vacuum, enabling it to serve as an objective in various optical systems for imaging objects. The article delves into the structure and working principles of the hybrid prism, discussing its potential applications, including as an intraocular prism for macular degeneration, a lidar system for vehicle navigation, and objectives for cameras, telescopes, microscopes, X-ray devices, and X-ray microscopes. The revolutionary hybrid prism unlocks precise imaging of light and X-rays, reshaping optical systems and enabling groundbreaking applications.展开更多
Commercial aluminum（grade 1900） in rotary motion was exposed to slurry of sand in water.Samples were mounted at various angles and rotated at different speeds.Wear rate was calculated using mass loss measurement.The...Commercial aluminum（grade 1900） in rotary motion was exposed to slurry of sand in water.Samples were mounted at various angles and rotated at different speeds.Wear rate was calculated using mass loss measurement.The results show that wear rates increase with increasing impingement angle up to 90°.Contrary to the conventional understanding of maximum loss of ductile material at about 45° impingement angle,maximum wear rate was observed in case of the aluminum sample fixed at 90°.However,increasing rotation speed of the samples results in exponential increase in wear rate.The findings are substantiated with the metallographic study of worn surface.展开更多
Poor recovery of neuronal functions is one of the most common healthcare challenges for patients with different types of brain injuries and/or neurodegenerative diseases.Therapeutic interventions face two major challe...Poor recovery of neuronal functions is one of the most common healthcare challenges for patients with different types of brain injuries and/or neurodegenerative diseases.Therapeutic interventions face two major challenges:(1)How to generate neurons de novo to replenish the neuronal loss caused by injuries or neurodegeneration(restorative neurogenesis)and(2)How to prevent or limit the secondary tissue damage caused by long-term accumulation of glial cells,including microglia,at injury site(glial scar).In contrast to mammals,zebrafish have extensive regenerative capacity in numerous vital organs,including the brain,thus making them a valuable model to improve the existing therapeutic approaches for human brain repair.In response to injuries to the central nervous system(CNS),zebrafish have developed specific mechanisms to promote the recovery of the lost tissue architecture and functionality of the damaged CNS.These mechanisms include the activation of a restorative neurogenic program in a specific set of glial cells(ependymoglia)and the resolution of both the glial scar and inflammation,thus enabling proper neuronal specification and survival.In this review,we discuss the cellular and molecular mechanisms underlying the regenerative ability in the adult zebrafish brain and conclude with the potential applicability of these mechanisms in repair of the mammalian CNS.展开更多
Rainfall samples were collected from three observation sites in Guilin from 2013 to 2017, and the chemical composition characteristics of precipitation and the contribution made by different ion sources were analyzed ...Rainfall samples were collected from three observation sites in Guilin from 2013 to 2017, and the chemical composition characteristics of precipitation and the contribution made by different ion sources were analyzed when atmospheric pollutants levels were reduced. The results showed that acid gas emissions and atmospheric pollutant concentrations continued to decline during the study period. However, the change in the volume-weighted mean p H at the three sites suggested that acid rain pollution was not alleviated and began to deteriorate after 2015. The continuing downward trend for alkaline neutralizing ions(Ca^(2+), NH_4^+) in precipitation indicated that the reduction in alkaline neutralizing substances in the atmosphere was an important factor that led to the deterioration in acid rain across Guilin. The principal component analysis and spearman correlation analysis indicated five sources of ions in precipitation. Quantitative assessment of these five sources indicated that fossil fuel combustion contributed the most ions concentration in precipitation at the three sites, followed by agriculture, terrestrial(crustal) sources, marine sources, and biomass burning. Long-distance airflow might affect the acidity, the electrical conductivity(EC), and ion concentrations in precipitation across Guilin. The airflow trajectory from the west and southeast directions corresponded to higher acidity and ion concentrations. According to the current air pollution control strategy planned by Guilin, reducing atmospheric coarse particles and NH_3 at the same time may potentially lead to further deteriorations in acid rain contents. Therefore, Guilin needs to develop more reasonable pollution prevention measures that synergistically control atmospheric pollutants and acid rain pollution.展开更多
The nucleus accumbens shell(NAcSh) plays an important role in reward and aversion. Traditionally, NAc dopamine receptor 2-expressing(D2) neurons are assumed to function in aversion. However, this has been challenged b...The nucleus accumbens shell(NAcSh) plays an important role in reward and aversion. Traditionally, NAc dopamine receptor 2-expressing(D2) neurons are assumed to function in aversion. However, this has been challenged by recent reports which attribute positive motivational roles to D2 neurons. Using optogenetics and multiple behavioral tasks, we found that activation of D2 neurons in the dorsomedial NAcSh drives preference and increases the motivation for rewards, whereas activation of ventral NAcSh D2 neurons induces aversion. Stimulation of D2 neurons in the ventromedial NAcSh increases movement speed and stimulation of D2 neurons in the ventrolateral NAc Sh decreases movement speed. Combining retrograde tracing and in situ hybridization, we demonstrated that glutamatergic and GABAergic neurons in the ventral pallidum receive inputs differentially from the dorsomedial and ventral NAcSh. All together, these findings shed light on the controversy regarding the function of NAcSh D2 neurons, and provide new insights into understanding the heterogeneity of the NAcSh.展开更多
The labile organic carbon(C)and C-related enzymes are sensitive indicators capturing alterations of soil organic matter(SOM),even in a short-time scale.Although the effects of crop husbandry and land use change on the...The labile organic carbon(C)and C-related enzymes are sensitive indicators capturing alterations of soil organic matter(SOM),even in a short-time scale.Although the effects of crop husbandry and land use change on these attributes have been well studied,there is no consensus about how plant phenology may impact them.This study aimed to determine the short-term effect o f six distinct phenological stages(PS-1:full bloom;PS-2:fruit set;PS-3:pit hardening;PS-4:physiological maturity;PS-5:60 d after physiological maturity;and PS-6:fall)o f peach on the changes in soil organic carbon(SOC)fractions of different oxidizability,labile C pools,and C-cycle enzyme activities in soils,for two consecutive years(2015 and 2016)in the North-Western Himalayas(NWH).Peach rhizosphere soils were sampled at the topsoil(0-15 cm)and subsoil(16-30 cm)layers,along with rhizosphere soils from adjacent perennial grasses,which served as a control.Values for most of the assessed parameters,including very labile C,labile C,microbial biomass C,permanganate oxidizable C,dissolved organic C,mineralizable C,amylase activity,and carboxymethyl-cellulase activity,were significantly(P<0.05)higher at PS-3 than at other phenological stages of peach.Conversely,a sudden decline in these soil variables was recorded at PS-5,followed by a slight buildup at PS-6,particularly in the topsoil of the peach orchard.Short-term changes in organic C fractions of different oxidizability,influenced by peach phenological stage,significantly(P<0.05)affected C management index,C pool index,and lability index.Both the C management index and lability index showed their highest values at PS-3 and their lowest values at PS-5,clearly indicating short-term accretion and depletion of SOC,in tandem with the peach phenological events.Principal component analysis suggested that a composite of soil indicators,including microbial biomass C,dissolved organic C,amylase,and invertase,could help detect short-term changes in SOC content.It is concluded that peach phenological events had a major impact on the short-term variations of the studied soil variables,which could be attributed to changes in the above-and belowground plant residues,as well as the extent of nutrients and water acquisition.展开更多
Background: Musculoskeletal injuries(MSkIs) are a leading cause of health care utilization, as well as limited duty and disability in the US military and other armed forces. MSkIs affect members of the military during...Background: Musculoskeletal injuries(MSkIs) are a leading cause of health care utilization, as well as limited duty and disability in the US military and other armed forces. MSkIs affect members of the military during initial training,operational training, and deployment and have a direct negative impact on overall troop readiness. Currently, a systematic overview of all risk factors for MSkIs in the military is not available.Methods: A systematic literature search was carried out using the PubMed, Ovid/Medline, and Web of Science databases from January 1, 2000 to September 10, 2019. Additionally, a reference list scan was performed(using the “snowball method”). Thereafter, an international, multidisciplinary expert panel scored the level of evidence per risk factor, and a classification of modifiable/non-modifiable was made.Results: In total, 176 original papers and 3 meta-analyses were included in the review. A list of 57 reported potential risk factors was formed. For 21 risk factors, the level of evidence was considered moderate or strong. Based on this literature review and an in-depth analysis, the expert panel developed a model to display the most relevant risk factors identified, introducing the idea of the “order of importance” and including concepts that are modifiable/nonmodifiable, as well as extrinsic/intrinsic risk factors.Conclusions: This is the qualitative systematic review of studies on risk factors for MSkIs in the military that has attempted to be all-inclusive. A total of 57 different potential risk factors were identified, and a new, prioritizing injury model was developed. This model may help us to understand risk factors that can be addressed, and in which order they should be prioritized when planning intervention strategies within military groups.展开更多
Titanium(IV) oxide (TiO2) nanoparticles have been incorporated into mixed matrix membranes (MMMs) to improve gas separation performance. However, TiO2 nanoparticles tend to agglomerate due to high surface energy and v...Titanium(IV) oxide (TiO2) nanoparticles have been incorporated into mixed matrix membranes (MMMs) to improve gas separation performance. However, TiO2 nanoparticles tend to agglomerate due to high surface energy and van der Waals forces. This leads to precipitation which causes the formation of non-homogeneous MMM morphology. In this study, the effect of octaisobutyl polyhedral oligomeric silsesquioxane (POSS) addition on TiO2/polysulfone MMM was investigated. The aims are to enhance gas separation performance whilst preventing agglomeration of TiO2 nanoparticles. The results demonstrated that inclusion of POSS as dispersant increases MMMs’ CO2/CH4 selectivity and permeance, possibly due to less void formation and more evenly distributed pore structure. For example, synergistic addition of 5 wt% TiO2 and 5 wt% POSS increased the CO2/CH4 selectivity up to 390% compared to MMM without POSS. This is supported by elemental mapping of titanium which revealed that POSS successfully dispersed TiO2 nanoparticles and prevented aggregation. TiO2-POSS/PSf MMMs also retained their favorable thermal stability.展开更多
Distribution of Sm and Ce in mice was investigated after inhalation exposure to their oxide particles of 5 μm diameter and 15 mg/m3.Sm and Ce were mainly distributed in lung,their concentrations decreased with passin...Distribution of Sm and Ce in mice was investigated after inhalation exposure to their oxide particles of 5 μm diameter and 15 mg/m3.Sm and Ce were mainly distributed in lung,their concentrations decreased with passing time,and their concentrations in lung were correlated with exposure periods.Concentrations of Ce were lower than that of Sm in each point.Sm was also distributed in the other organs and bone but Ce was scarcely detected.These results suggest that the behaviors of Sm and Ce inhaled were different,although their chemical properties are similar.展开更多
The aim of this research was to assess the influence of saline irrigation water which prepared to obtain salt stress of 0.31,3.21,5.74,8.28 and 12.86 dS/m on seed germination,and early seedling growth of 10 cultivars(...The aim of this research was to assess the influence of saline irrigation water which prepared to obtain salt stress of 0.31,3.21,5.74,8.28 and 12.86 dS/m on seed germination,and early seedling growth of 10 cultivars(Giza 123,124,125,126,127,129,130,134,135 and 2000)of Egyptian barley grown in clay loam soil.Germination was tested in germination cups filled with clay loam soil moistened with different concentrations of saline water,in the growth chambers condition.Results indicated that,the highest values of germinated seeds were recorded mainly at fresh water(0.31 dS/m)at all germination periods.Also,the maximum values were recorded at investigated barley cultivars Giza 126,127 and 2000 for three studied periods(3,5 and 7 d),while Giza 129,130 and 135 got the same trend where the highest values for germinated seeds attained at the 5 d,7 d and at 3 d were 9.5 seeds,respectively.Barley cultivar Giza 126 had significantly higher root length(4.07 cm),shoot length(11.75 cm),root fresh weight(48.2 mg),shoot fresh weight(101.1 mg),root dry weight(7.1 mg),shoot dry weight(6.6 mg)and seedling vigor index(13.44).The 6 kDa protein bands had the same increasing after salt stress in cultivars Giza 123,127,129,134 and 135.Barley cultivars in clay soil can be classified into barley cultivars Giza 126,127 and 2000 as highly tolerance and barley cultivar Giza 129,123 and 127 as moderately tolerance and the rest is less.展开更多
An internal transport barrier(ITB)can be formed on EAST in exploring high-parameter operation.Previous studies show that safety factor(q)profiles,Shafranov shift and magnetohydrodynamic behaviors could be helpful in I...An internal transport barrier(ITB)can be formed on EAST in exploring high-parameter operation.Previous studies show that safety factor(q)profiles,Shafranov shift and magnetohydrodynamic behaviors could be helpful in ITB formation by suppressing anomalous transport.Recently,electron density evolution with high resolution demonstrates that fishbone could be dominant in electron density ITB formation and sustainment.The power threshold is low in the fishbone condition and the electron density profile is determined by traits of fishbone.Simulation shows that the low-k ion mode is suppressed by fishbone.Direct measurement of turbulence in the inner region shows that the internal kink mode could sustain an electron temperature ITB by suppressing the trapped electron mode.The multi-scale interaction between the kink mode and turbulence by current could be key in sustaining high-electron-temperature long-pulse operation.展开更多
With the rapid development of wireless communication technology,the spectrum resources are increasingly strained which needs optimal solutions.Cognitive radio(CR)is one of the key technologies to solve this problem.Sp...With the rapid development of wireless communication technology,the spectrum resources are increasingly strained which needs optimal solutions.Cognitive radio(CR)is one of the key technologies to solve this problem.Spectrum sensing not only includes the precise detection of the communication signal of the primary user(PU),but also the precise identification of its modulation type,which can then determine the a priori information such as the PU’service category,so as to use this information to make the cognitive user(CU)aware to discover and use the idle spectrum more effectively,and improve the spectrum utilization.Spectrum sensing is the primary feature and core part of CR.Classical sensing algorithms includes energy detection,cyclostationary feature detection,matched filter detection,and so on.The energy detection algorithm has a simple structure and does not require prior knowledge of the PU transmitter signal,but it is easily affected by noise and the threshold is not easy to determine.The combination of multiple-input multiple-output(MIMO)with CR improves the spectral efficiency and multipath fading utilization.To best utilize the PU spectrum while minimizing the overall transmit power,an iterative technique based on semidefinite programming(SDP)and minimum mean squared error(MMSE)is proposed.Also,this article proposed a new method for max-min fairness beamforming.When compared to existing algorithms,the simulation results show that the proposed algorithms perform better in terms of total transmitted power and signal-tointerference plus noise ratio(SINR).Furthermore,the proposed algorithm effectively improved the system performance in terms of number of iterations,interference temperature threshold and balance SINR level which makes it superior over the conventional schemes.展开更多
[Objective]Species composition and flora of vascular plants in the middle and upper reaches of the Yarlung Zangbo River were analyzed,to provide scientific basis for the estimation and protection of plant diversity,co...[Objective]Species composition and flora of vascular plants in the middle and upper reaches of the Yarlung Zangbo River were analyzed,to provide scientific basis for the estimation and protection of plant diversity,construction of ecological security shelter for the Tibetan Plateau.[Methods]In the middle and upper reaches of the Yarlung Zangbo River,quadrat(line transect)method was applied to investigate the phytocoenoses in sample plots,and relative literature was used to analyze the floristic composition and floristic element of vascular plants in the middle and upper reaches of the Yarlung Zangbo River.[Results]①There are 96 species(including subspecies and variations),69 genera of 35 vascular plant families,accounting for 16.83%,5.48%,1.66%and 11.63%,2.02%,0.31%of total vascular plant families,genera and species in Xizang and China.②There are 24 monotypic-genus families,accounting for 68.57%of the total family number in the local area;22 monotypic-species families,accounting for 62.86%of the total family number in the local area.Local flora shows the characteristics of ancient relict,such as Euphorbiaceae,Rubiaceae,Liliaceae and Ranunculaceae,they are all ancient primitive groups of the third flora and the fourth flora.③Local vascular plant genera fall into 10 areal types and 8 variations.④Temperate elements are much more than tropical elements,R/T is 0.19,indicating that vascular plants have typical temperate nature and residual tropical nature.There are only a few endemic genera,but more endemic species to the local area,and these species are closely related,of which there are some transitional species,indicating that local flora is too young to experience more differentiation and specialization.⑤There are 24 Chinese endemic species,accounting for 25%of total number of species in the local area;among which there are 12 endemic species to Tibet,accounting for 50%of endemic species to China,12.5%of total number of species in the local area.Four key wild plant species are included in the second batch of national key protection.[Conclusions]①There are scarce plant groups in the local area.②Among the obvious advantages,single-genus(species)families possess the absolute advantage,and the flora has ancient origins.③The local flora has diversified distribution types,and the complicated geographical elements.④Temperate species possess obvious advantages,and the flora is young.⑤Rich unique and rare species have high species diversity protection and research value.展开更多
Objective: To assess the extent of heterogeneity of the genetic risk of age- related macular disease (AMD) among families. Design: Case- controlled population- based familial aggregation study. Participants: Participa...Objective: To assess the extent of heterogeneity of the genetic risk of age- related macular disease (AMD) among families. Design: Case- controlled population- based familial aggregation study. Participants: Participants comprised 190 first- degree relatives of 65 case probands and 347 relatives of 100 control probands. All probands had been identified from the baseline phase of the Rotterdam Study in The Netherlands. Methods: A family score was computed for each family based on the presence and type of macular disease, the expected risk of disease, and the number, extent of kinship, and age of all family members. Main Outcome Measures: Presence and stage of AMD as diagnosed on fundus photographs, family score, and logistic regression coefficient. Results: The family score of case families showed a peak of approximately 0 with a skewed tail (14% of families) of higher than expected risks of disease toward a maximum of 2.9. The family score of control families centered on 0, apart from 1 outlier. The risk of AMD increased significantly with higher family scores (β =1.34; P< 0.001). Conclusions: The heterogeneity of genetic risk among AMD families is considerable, and the proportion of high- risk families is relatively small. The family score method is relevant for genetic counseling as well as for implementation in studies of genetic dissection of AMD.展开更多
To examine the long term effects of polio, maximal vo luntary strength and voluntary activation of elbow flexor muscles of 177 patients from a postpolio clinic were investigated using twitch interpolation. Muscle endu...To examine the long term effects of polio, maximal vo luntary strength and voluntary activation of elbow flexor muscles of 177 patients from a postpolio clinic were investigated using twitch interpolation. Muscle endurance was studied in 142 patients during 45 min of submaximal exercise, and predictors of impaired muscle performance were investigated. Twentynine of 177 patients (16.4% ) had impaired voluntary drive to their elbowflexor muscles, but only 16 (9.0% ) had markedly reduced elbow flexor strength, despite 74 (41.8% ) reporting they were initially affected in their tested limb and 172 (97.2% ) patients reporting new generalized symptoms. Seven patients had impaired muscle endurance in the tests of strength and voluntary drive. During the submaximal exercise, 16 patients (11.3% ) had impaired peripheral muscle endurancewith normal voluntary activation. These results confirm a low incidence of impaired upper limb muscle performance in postpolio patients, despite many patients having subjective symptoms consistent with postpolio syndrome. There was an increased relative risk for impaired muscle function in those patients with a subjective decrease in strength in the tested limb, a recent decline in activities of daily living in their tested limb, and who used orthotic devices in their tested limb. Monitoring of function in prior polio patients with impaired muscle performance may be useful, particularly when combined with investigation of other potential contributory factors to the functional impairment.展开更多
The main unifying feature of cases with frontotemporal dementia (FTD) is the p attern of brain atrophy. Surprisingly, there are a variety of underlying histopa thologies in cases with the clinical features and typical...The main unifying feature of cases with frontotemporal dementia (FTD) is the p attern of brain atrophy. Surprisingly, there are a variety of underlying histopa thologies in cases with the clinical features and typical pattern of atrophy cha racterizing FTD. This suggests that the degenerative mechanism(s) associated wit h pyramidal cell loss and gliosis in FTD is likely to be similar in the differen t histopathological forms of the disease. In this study we tested this hypothesi s by analysing a common cell death mechanism, apoptosis, in cases of FTD with ei ther Picks disease (PiD) (n = 9) or frontotemporal lobar degeneration (FTLD) ( n = 7) compared with normal controls (n = 10). Tissue sections from previously a nalysed cases were stained using anti activated caspase-3 immunohistochemistry , TUNEL, propidium iodide, and cell and pathology specific labels. These marke rs of apoptosis identified both astrocytes and neurons in regions vulnerable to degeneration in all cases of FTD. However, neuronal apoptosis was rare (<2 %of neurons), even at early disease stages where there is considerably less fro ntotemporal atrophy or pyramidal cell loss. This suggests that other cell death mechanisms account for the progressive neuronal loss in FTD. In contrast, astroc ytes with beaded processes and other apoptotic features were very frequent in bo th PiD and FTLD, with the severity of astrocytosis and astrocytic apoptosis corr elating with both the degree of neuronal loss and the stage of disease. These fi ndings provide evidence that astrocytic apoptosis occurs as an early event in di fferent histopathological forms of FTD. Furthermore, this astrocytic apoptosis d irectly relates to the degree of degeneration in FTD, and becomes the overwhelmi ng pathological feature as the disease progresses.展开更多
基金This publication is based upon work from COST Action CLIMO(CA15226) supported by COST (European Cooperation in Science and Technology)the UMBRACLIM project (PID2019-111781RB-I00)funded by the Spanish Ministry for Science and Innovation. Teresa Valor was contracted with a grant“Juan de la Cierva-Formaci on”(FJC2018-036673-I). Z.S. received funds from the grant no. APVV-20-0365 and from project TreeAdapt supported by the MPRV SR. Aitor Ameztegui is supported by a Serra-Húnter fellowship by the Generalitat de Catalunya。
文摘Background: Understanding the role of species identity in interactions among individuals is crucial for assessing the productivity and stability of mixed forests over time. However, there is limited knowledge concerning the variation in competitive effect and response of different species along climatic gradients. In this study, we investigated the importance of climate, tree size, and competition on the growth of three tree species: spruce(Picea abies), fir(Abies alba), and beech(Fagus sylvatica), and examined their competitive response and effect along a climatic gradient.Methods: We selected 39 plots distributed across the European mountains with records of the position and growth of 5,759 individuals. For each target species, models relating tree growth to tree size, climate and competition were proposed. Competition was modelled using a neighbourhood competition index that considered the effects of inter-and intraspecific competition on target trees. Competitive responses and effects were related to climate.Likelihood methods and information theory were used to select the best model.Results: Our findings revealed that competition had a greater impact on target species growth than tree size or climate. Climate did influence the competitive effects of neighbouring species, but it did not affect the target species? response to competition. The strength of competitive effects varied along the gradient, contingent on the identity of the interacting species. When the target species exhibited an intermediate competitive effect relative to neighbouring species, both higher inter-than intraspecific competitive effects and competition reduction occurred along the gradient. Notably, species competitive effects were most pronounced when the target species' growth was at its peak and weakest when growing conditions were far from their maximum.Conclusions: Climate modulates the effects of competition from neighbouring trees on the target tree and not the susceptibility of the target tree to competition. The modelling approach should be useful in future research to expand our knowledge of how competition modulates forest communities across environmental gradients.
文摘Filtration has been widely used in re-circulating aquaculture system to remove waste. However, the study of some agricultural residues （corn） usage as the filter medium has not yet been studied. Therefore, the aim of this study is to construct a filter made from inexpensive and readily available corn residues and to analyze its effectiveness in controlling suspended solids that directly impact health of fish through abrasion of gill tissues or indirectly through water quality deterioration. The performance evaluation procedure was carried out in an aquaculture system with production in glass tanks located indoor in laboratory at Faculty of Agriculture, Damietta University, Egypt. The evaluation included three concentrations of total suspended solids （450, 900 and 1,350 mg/L）; four residues particle size distribution （3.35, 9.53, 12.7 mm and ascending order to mentioned sizes from bottom to top）; and four thicknesses of filter layer （9, 21, 33 and 45 cm）. The effectiveness of this filter was measured by determining filter efficiency （ηf）, % and filtration rate （FR）, mL/min. It was observed that the maximum value of （ηf）, % was achieved at 450 mg/L concentration of total suspended solids, ascending order to sizes from bottom to top and 45 cm thickness of filtration layer. The maximum value of filtration rate was achieved at 450 mg/l concentration of total suspended solids, 12.7 mm particle size distribution and 9 cm thickness of filter layer. Results indicated that this filter is efficient enough to remove suspended solids. Therefore, this milled corn residues filter can be used in aquaculture systems for Nile tilapia, Oreochromis niloticus culture system.
基金Supported by National Key R&D Program(2016YFC0502006)Major Science and Technology Projects of Tibet(Z2016C01G01/02)Opening Fund for Joint Laboratory of Ecological Security in Tibet(STX2018-15)
文摘With seeds of Caragana versicolor in Purang County,Xizang as the materials,the seed germination and seedling growth of C.versicolor were measured under acid and alkali stress,and the soil acidity and alkalinity for normal growth and development of C.versicolor were determined,so as to provide the theoretical basis for cultivation of C.versicolor in acidified or alkaline soil.The results showed that the seed germination of C.versicolor was promoted when treated by strong acid(pH 3)and strong alkali(pH 11)solutions,and the seedling effect was good.The results also indicated that C.versicolor was a kind of plant with strong acid and alkali resistance,suitable for cultivation in acid and alkali soil areas.
基金Supported by National Key R&D Program of China(2016YFC0502006)Major Science and Technology Projects of Tibet(Z2016C01G01/02)
文摘The research aimed to analyze changes in photosynthetic characteristics of Paeonia ludlowii under saline-alkali stress,and annual seedlings of P.ludlowii were taken as the materials.Photoresponse process of P.ludlowii leaves under saline-alkali stress was simulated,and different models were used to fit photoresponse curve.The results showed that P n of P.ludlowii leaves showed the trend of first rising and then declining with PAR increased under saline-alkali stress;both G s and T r showed a rising trend with PAR increased;C i showed the trend of first declining and then rising with PAR increased.Photoresponse curve fitted by modified rectangular hyperbolic model had the best effect,and it was the optimal fitting model.P.ludlowii could adapt to saline-alkali stress in lower concentration,showing that P.ludlowii could be introduced and cultivated in saline-alkali land at a lower level.
文摘This research article introduces and explores the concept of a hybrid prism, which combines the properties of a lens and a reflective prism, designed for optical systems that operate in different spectral ranges of electromagnetic waves. The hybrid prism allows for precise focusing of light rays in a glass body and X-rays in a vacuum, enabling it to serve as an objective in various optical systems for imaging objects. The article delves into the structure and working principles of the hybrid prism, discussing its potential applications, including as an intraocular prism for macular degeneration, a lidar system for vehicle navigation, and objectives for cameras, telescopes, microscopes, X-ray devices, and X-ray microscopes. The revolutionary hybrid prism unlocks precise imaging of light and X-rays, reshaping optical systems and enabling groundbreaking applications.
文摘Commercial aluminum（grade 1900） in rotary motion was exposed to slurry of sand in water.Samples were mounted at various angles and rotated at different speeds.Wear rate was calculated using mass loss measurement.The results show that wear rates increase with increasing impingement angle up to 90°.Contrary to the conventional understanding of maximum loss of ductile material at about 45° impingement angle,maximum wear rate was observed in case of the aluminum sample fixed at 90°.However,increasing rotation speed of the samples results in exponential increase in wear rate.The findings are substantiated with the metallographic study of worn surface.
基金Supported by the German Research foundation(DFG),No.SFB 870
文摘Poor recovery of neuronal functions is one of the most common healthcare challenges for patients with different types of brain injuries and/or neurodegenerative diseases.Therapeutic interventions face two major challenges:(1)How to generate neurons de novo to replenish the neuronal loss caused by injuries or neurodegeneration(restorative neurogenesis)and(2)How to prevent or limit the secondary tissue damage caused by long-term accumulation of glial cells,including microglia,at injury site(glial scar).In contrast to mammals,zebrafish have extensive regenerative capacity in numerous vital organs,including the brain,thus making them a valuable model to improve the existing therapeutic approaches for human brain repair.In response to injuries to the central nervous system(CNS),zebrafish have developed specific mechanisms to promote the recovery of the lost tissue architecture and functionality of the damaged CNS.These mechanisms include the activation of a restorative neurogenic program in a specific set of glial cells(ependymoglia)and the resolution of both the glial scar and inflammation,thus enabling proper neuronal specification and survival.In this review,we discuss the cellular and molecular mechanisms underlying the regenerative ability in the adult zebrafish brain and conclude with the potential applicability of these mechanisms in repair of the mammalian CNS.
基金supported by the Special Scientific Research Business of Central-level Public Welfare Research Institutes (No. 2015-YSKY-09)the Guangxi Key Research and Development Plan for Department of Guangxi Science (No. GUIKEAB16380292)。
文摘Rainfall samples were collected from three observation sites in Guilin from 2013 to 2017, and the chemical composition characteristics of precipitation and the contribution made by different ion sources were analyzed when atmospheric pollutants levels were reduced. The results showed that acid gas emissions and atmospheric pollutant concentrations continued to decline during the study period. However, the change in the volume-weighted mean p H at the three sites suggested that acid rain pollution was not alleviated and began to deteriorate after 2015. The continuing downward trend for alkaline neutralizing ions(Ca^(2+), NH_4^+) in precipitation indicated that the reduction in alkaline neutralizing substances in the atmosphere was an important factor that led to the deterioration in acid rain across Guilin. The principal component analysis and spearman correlation analysis indicated five sources of ions in precipitation. Quantitative assessment of these five sources indicated that fossil fuel combustion contributed the most ions concentration in precipitation at the three sites, followed by agriculture, terrestrial(crustal) sources, marine sources, and biomass burning. Long-distance airflow might affect the acidity, the electrical conductivity(EC), and ion concentrations in precipitation across Guilin. The airflow trajectory from the west and southeast directions corresponded to higher acidity and ion concentrations. According to the current air pollution control strategy planned by Guilin, reducing atmospheric coarse particles and NH_3 at the same time may potentially lead to further deteriorations in acid rain contents. Therefore, Guilin needs to develop more reasonable pollution prevention measures that synergistically control atmospheric pollutants and acid rain pollution.
基金supported by National Science Foundation of China grants 31571095 and 91332122a Key Scientific Technological Innovation Research project from the Ministry of Education+1 种基金a grant from Insitute Guo Qiang at Tsinghua Universityfunding from the Beijing Program on the Study of Functional Chips and Related Core Technologies of Brain-inspired Computing Systems。
文摘The nucleus accumbens shell(NAcSh) plays an important role in reward and aversion. Traditionally, NAc dopamine receptor 2-expressing(D2) neurons are assumed to function in aversion. However, this has been challenged by recent reports which attribute positive motivational roles to D2 neurons. Using optogenetics and multiple behavioral tasks, we found that activation of D2 neurons in the dorsomedial NAcSh drives preference and increases the motivation for rewards, whereas activation of ventral NAcSh D2 neurons induces aversion. Stimulation of D2 neurons in the ventromedial NAcSh increases movement speed and stimulation of D2 neurons in the ventrolateral NAc Sh decreases movement speed. Combining retrograde tracing and in situ hybridization, we demonstrated that glutamatergic and GABAergic neurons in the ventral pallidum receive inputs differentially from the dorsomedial and ventral NAcSh. All together, these findings shed light on the controversy regarding the function of NAcSh D2 neurons, and provide new insights into understanding the heterogeneity of the NAcSh.
文摘The labile organic carbon(C)and C-related enzymes are sensitive indicators capturing alterations of soil organic matter(SOM),even in a short-time scale.Although the effects of crop husbandry and land use change on these attributes have been well studied,there is no consensus about how plant phenology may impact them.This study aimed to determine the short-term effect o f six distinct phenological stages(PS-1:full bloom;PS-2:fruit set;PS-3:pit hardening;PS-4:physiological maturity;PS-5:60 d after physiological maturity;and PS-6:fall)o f peach on the changes in soil organic carbon(SOC)fractions of different oxidizability,labile C pools,and C-cycle enzyme activities in soils,for two consecutive years(2015 and 2016)in the North-Western Himalayas(NWH).Peach rhizosphere soils were sampled at the topsoil(0-15 cm)and subsoil(16-30 cm)layers,along with rhizosphere soils from adjacent perennial grasses,which served as a control.Values for most of the assessed parameters,including very labile C,labile C,microbial biomass C,permanganate oxidizable C,dissolved organic C,mineralizable C,amylase activity,and carboxymethyl-cellulase activity,were significantly(P<0.05)higher at PS-3 than at other phenological stages of peach.Conversely,a sudden decline in these soil variables was recorded at PS-5,followed by a slight buildup at PS-6,particularly in the topsoil of the peach orchard.Short-term changes in organic C fractions of different oxidizability,influenced by peach phenological stage,significantly(P<0.05)affected C management index,C pool index,and lability index.Both the C management index and lability index showed their highest values at PS-3 and their lowest values at PS-5,clearly indicating short-term accretion and depletion of SOC,in tandem with the peach phenological events.Principal component analysis suggested that a composite of soil indicators,including microbial biomass C,dissolved organic C,amylase,and invertase,could help detect short-term changes in SOC content.It is concluded that peach phenological events had a major impact on the short-term variations of the studied soil variables,which could be attributed to changes in the above-and belowground plant residues,as well as the extent of nutrients and water acquisition.
文摘Background: Musculoskeletal injuries(MSkIs) are a leading cause of health care utilization, as well as limited duty and disability in the US military and other armed forces. MSkIs affect members of the military during initial training,operational training, and deployment and have a direct negative impact on overall troop readiness. Currently, a systematic overview of all risk factors for MSkIs in the military is not available.Methods: A systematic literature search was carried out using the PubMed, Ovid/Medline, and Web of Science databases from January 1, 2000 to September 10, 2019. Additionally, a reference list scan was performed(using the “snowball method”). Thereafter, an international, multidisciplinary expert panel scored the level of evidence per risk factor, and a classification of modifiable/non-modifiable was made.Results: In total, 176 original papers and 3 meta-analyses were included in the review. A list of 57 reported potential risk factors was formed. For 21 risk factors, the level of evidence was considered moderate or strong. Based on this literature review and an in-depth analysis, the expert panel developed a model to display the most relevant risk factors identified, introducing the idea of the “order of importance” and including concepts that are modifiable/nonmodifiable, as well as extrinsic/intrinsic risk factors.Conclusions: This is the qualitative systematic review of studies on risk factors for MSkIs in the military that has attempted to be all-inclusive. A total of 57 different potential risk factors were identified, and a new, prioritizing injury model was developed. This model may help us to understand risk factors that can be addressed, and in which order they should be prioritized when planning intervention strategies within military groups.
基金financial support received from YUTP-FRG (No. 015 3AA-E08)FRGS (Ref. No. FRGS/1/2018/TK02/UTP/02/3, Cost Center 015MA0003)
文摘Titanium(IV) oxide (TiO2) nanoparticles have been incorporated into mixed matrix membranes (MMMs) to improve gas separation performance. However, TiO2 nanoparticles tend to agglomerate due to high surface energy and van der Waals forces. This leads to precipitation which causes the formation of non-homogeneous MMM morphology. In this study, the effect of octaisobutyl polyhedral oligomeric silsesquioxane (POSS) addition on TiO2/polysulfone MMM was investigated. The aims are to enhance gas separation performance whilst preventing agglomeration of TiO2 nanoparticles. The results demonstrated that inclusion of POSS as dispersant increases MMMs’ CO2/CH4 selectivity and permeance, possibly due to less void formation and more evenly distributed pore structure. For example, synergistic addition of 5 wt% TiO2 and 5 wt% POSS increased the CO2/CH4 selectivity up to 390% compared to MMM without POSS. This is supported by elemental mapping of titanium which revealed that POSS successfully dispersed TiO2 nanoparticles and prevented aggregation. TiO2-POSS/PSf MMMs also retained their favorable thermal stability.
基金Project partially supported by the Grant-in-Aid for Scientific Research (c)21590665,JSPS,Japan
文摘Distribution of Sm and Ce in mice was investigated after inhalation exposure to their oxide particles of 5 μm diameter and 15 mg/m3.Sm and Ce were mainly distributed in lung,their concentrations decreased with passing time,and their concentrations in lung were correlated with exposure periods.Concentrations of Ce were lower than that of Sm in each point.Sm was also distributed in the other organs and bone but Ce was scarcely detected.These results suggest that the behaviors of Sm and Ce inhaled were different,although their chemical properties are similar.
文摘The aim of this research was to assess the influence of saline irrigation water which prepared to obtain salt stress of 0.31,3.21,5.74,8.28 and 12.86 dS/m on seed germination,and early seedling growth of 10 cultivars(Giza 123,124,125,126,127,129,130,134,135 and 2000)of Egyptian barley grown in clay loam soil.Germination was tested in germination cups filled with clay loam soil moistened with different concentrations of saline water,in the growth chambers condition.Results indicated that,the highest values of germinated seeds were recorded mainly at fresh water(0.31 dS/m)at all germination periods.Also,the maximum values were recorded at investigated barley cultivars Giza 126,127 and 2000 for three studied periods(3,5 and 7 d),while Giza 129,130 and 135 got the same trend where the highest values for germinated seeds attained at the 5 d,7 d and at 3 d were 9.5 seeds,respectively.Barley cultivar Giza 126 had significantly higher root length(4.07 cm),shoot length(11.75 cm),root fresh weight(48.2 mg),shoot fresh weight(101.1 mg),root dry weight(7.1 mg),shoot dry weight(6.6 mg)and seedling vigor index(13.44).The 6 kDa protein bands had the same increasing after salt stress in cultivars Giza 123,127,129,134 and 135.Barley cultivars in clay soil can be classified into barley cultivars Giza 126,127 and 2000 as highly tolerance and barley cultivar Giza 129,123 and 127 as moderately tolerance and the rest is less.
基金supported by the National Key R&D Program of China(No.2017YFE0301705)supported in part by the Key Program of Research and Development of Hefei Science Center,CAS(No.2019HSC-KPRD001)+1 种基金supported by National Natural Science Foundation of China(Nos.11975271 and 11675211)partly supported by the Collaborative Research Program of the Research Institute for Applied Mechanics,Kyushu University。
文摘An internal transport barrier(ITB)can be formed on EAST in exploring high-parameter operation.Previous studies show that safety factor(q)profiles,Shafranov shift and magnetohydrodynamic behaviors could be helpful in ITB formation by suppressing anomalous transport.Recently,electron density evolution with high resolution demonstrates that fishbone could be dominant in electron density ITB formation and sustainment.The power threshold is low in the fishbone condition and the electron density profile is determined by traits of fishbone.Simulation shows that the low-k ion mode is suppressed by fishbone.Direct measurement of turbulence in the inner region shows that the internal kink mode could sustain an electron temperature ITB by suppressing the trapped electron mode.The multi-scale interaction between the kink mode and turbulence by current could be key in sustaining high-electron-temperature long-pulse operation.
基金The authors extend their appreciation to the Deanship of Scientific Research at King Khalid University for funding this work under Grant Number(RGP 2/209/42)This research was funded by the Deanship of Scientific Research at Princess Nourah bint AbdulrahmanUniversity through the Fast-Track Path of Research Funding Program.
文摘With the rapid development of wireless communication technology,the spectrum resources are increasingly strained which needs optimal solutions.Cognitive radio(CR)is one of the key technologies to solve this problem.Spectrum sensing not only includes the precise detection of the communication signal of the primary user(PU),but also the precise identification of its modulation type,which can then determine the a priori information such as the PU’service category,so as to use this information to make the cognitive user(CU)aware to discover and use the idle spectrum more effectively,and improve the spectrum utilization.Spectrum sensing is the primary feature and core part of CR.Classical sensing algorithms includes energy detection,cyclostationary feature detection,matched filter detection,and so on.The energy detection algorithm has a simple structure and does not require prior knowledge of the PU transmitter signal,but it is easily affected by noise and the threshold is not easy to determine.The combination of multiple-input multiple-output(MIMO)with CR improves the spectral efficiency and multipath fading utilization.To best utilize the PU spectrum while minimizing the overall transmit power,an iterative technique based on semidefinite programming(SDP)and minimum mean squared error(MMSE)is proposed.Also,this article proposed a new method for max-min fairness beamforming.When compared to existing algorithms,the simulation results show that the proposed algorithms perform better in terms of total transmitted power and signal-tointerference plus noise ratio(SINR).Furthermore,the proposed algorithm effectively improved the system performance in terms of number of iterations,interference temperature threshold and balance SINR level which makes it superior over the conventional schemes.
基金Supported by National Key R&D Program of china(2016YFC0502006)Major Science and Technology Projects of Tibet(Z2016C01G01/02)
文摘[Objective]Species composition and flora of vascular plants in the middle and upper reaches of the Yarlung Zangbo River were analyzed,to provide scientific basis for the estimation and protection of plant diversity,construction of ecological security shelter for the Tibetan Plateau.[Methods]In the middle and upper reaches of the Yarlung Zangbo River,quadrat(line transect)method was applied to investigate the phytocoenoses in sample plots,and relative literature was used to analyze the floristic composition and floristic element of vascular plants in the middle and upper reaches of the Yarlung Zangbo River.[Results]①There are 96 species(including subspecies and variations),69 genera of 35 vascular plant families,accounting for 16.83%,5.48%,1.66%and 11.63%,2.02%,0.31%of total vascular plant families,genera and species in Xizang and China.②There are 24 monotypic-genus families,accounting for 68.57%of the total family number in the local area;22 monotypic-species families,accounting for 62.86%of the total family number in the local area.Local flora shows the characteristics of ancient relict,such as Euphorbiaceae,Rubiaceae,Liliaceae and Ranunculaceae,they are all ancient primitive groups of the third flora and the fourth flora.③Local vascular plant genera fall into 10 areal types and 8 variations.④Temperate elements are much more than tropical elements,R/T is 0.19,indicating that vascular plants have typical temperate nature and residual tropical nature.There are only a few endemic genera,but more endemic species to the local area,and these species are closely related,of which there are some transitional species,indicating that local flora is too young to experience more differentiation and specialization.⑤There are 24 Chinese endemic species,accounting for 25%of total number of species in the local area;among which there are 12 endemic species to Tibet,accounting for 50%of endemic species to China,12.5%of total number of species in the local area.Four key wild plant species are included in the second batch of national key protection.[Conclusions]①There are scarce plant groups in the local area.②Among the obvious advantages,single-genus(species)families possess the absolute advantage,and the flora has ancient origins.③The local flora has diversified distribution types,and the complicated geographical elements.④Temperate species possess obvious advantages,and the flora is young.⑤Rich unique and rare species have high species diversity protection and research value.
文摘Objective: To assess the extent of heterogeneity of the genetic risk of age- related macular disease (AMD) among families. Design: Case- controlled population- based familial aggregation study. Participants: Participants comprised 190 first- degree relatives of 65 case probands and 347 relatives of 100 control probands. All probands had been identified from the baseline phase of the Rotterdam Study in The Netherlands. Methods: A family score was computed for each family based on the presence and type of macular disease, the expected risk of disease, and the number, extent of kinship, and age of all family members. Main Outcome Measures: Presence and stage of AMD as diagnosed on fundus photographs, family score, and logistic regression coefficient. Results: The family score of case families showed a peak of approximately 0 with a skewed tail (14% of families) of higher than expected risks of disease toward a maximum of 2.9. The family score of control families centered on 0, apart from 1 outlier. The risk of AMD increased significantly with higher family scores (β =1.34; P< 0.001). Conclusions: The heterogeneity of genetic risk among AMD families is considerable, and the proportion of high- risk families is relatively small. The family score method is relevant for genetic counseling as well as for implementation in studies of genetic dissection of AMD.
文摘To examine the long term effects of polio, maximal vo luntary strength and voluntary activation of elbow flexor muscles of 177 patients from a postpolio clinic were investigated using twitch interpolation. Muscle endurance was studied in 142 patients during 45 min of submaximal exercise, and predictors of impaired muscle performance were investigated. Twentynine of 177 patients (16.4% ) had impaired voluntary drive to their elbowflexor muscles, but only 16 (9.0% ) had markedly reduced elbow flexor strength, despite 74 (41.8% ) reporting they were initially affected in their tested limb and 172 (97.2% ) patients reporting new generalized symptoms. Seven patients had impaired muscle endurance in the tests of strength and voluntary drive. During the submaximal exercise, 16 patients (11.3% ) had impaired peripheral muscle endurancewith normal voluntary activation. These results confirm a low incidence of impaired upper limb muscle performance in postpolio patients, despite many patients having subjective symptoms consistent with postpolio syndrome. There was an increased relative risk for impaired muscle function in those patients with a subjective decrease in strength in the tested limb, a recent decline in activities of daily living in their tested limb, and who used orthotic devices in their tested limb. Monitoring of function in prior polio patients with impaired muscle performance may be useful, particularly when combined with investigation of other potential contributory factors to the functional impairment.
文摘The main unifying feature of cases with frontotemporal dementia (FTD) is the p attern of brain atrophy. Surprisingly, there are a variety of underlying histopa thologies in cases with the clinical features and typical pattern of atrophy cha racterizing FTD. This suggests that the degenerative mechanism(s) associated wit h pyramidal cell loss and gliosis in FTD is likely to be similar in the differen t histopathological forms of the disease. In this study we tested this hypothesi s by analysing a common cell death mechanism, apoptosis, in cases of FTD with ei ther Picks disease (PiD) (n = 9) or frontotemporal lobar degeneration (FTLD) ( n = 7) compared with normal controls (n = 10). Tissue sections from previously a nalysed cases were stained using anti activated caspase-3 immunohistochemistry , TUNEL, propidium iodide, and cell and pathology specific labels. These marke rs of apoptosis identified both astrocytes and neurons in regions vulnerable to degeneration in all cases of FTD. However, neuronal apoptosis was rare (<2 %of neurons), even at early disease stages where there is considerably less fro ntotemporal atrophy or pyramidal cell loss. This suggests that other cell death mechanisms account for the progressive neuronal loss in FTD. In contrast, astroc ytes with beaded processes and other apoptotic features were very frequent in bo th PiD and FTLD, with the severity of astrocytosis and astrocytic apoptosis corr elating with both the degree of neuronal loss and the stage of disease. These fi ndings provide evidence that astrocytic apoptosis occurs as an early event in di fferent histopathological forms of FTD. Furthermore, this astrocytic apoptosis d irectly relates to the degree of degeneration in FTD, and becomes the overwhelmi ng pathological feature as the disease progresses.
