BACKGROUND Ventriculoperitoneal shunt(VPS)catheter insertion is one of the most widely accepted surgical procedures for hydrocephalus.Migration of the end of the distal VPS catheter into the scrotum is one of the rare...BACKGROUND Ventriculoperitoneal shunt(VPS)catheter insertion is one of the most widely accepted surgical procedures for hydrocephalus.Migration of the end of the distal VPS catheter into the scrotum is one of the rare complications of VPS catheter insertion.METHODS This is a systematic review of the published cases,and the literature search was performed from 1974 to June 30,2024,to retrieve the relevant manuscripts.The cases were grouped into two.Group A included cases of migration of the distal VPS catheter into the scrotum,detected in children.Group B included the cases of migration of the distal VPS catheter into the scrotum,which was detected in adults and older people.RESULTS One hundred-twenty cases of migration of the distal end of VPS catheter into the scrotum were included in this study,a systematic literature review.Group A included n=112 cases,and group B included n=8 cases only.Three-fourths of the cases involved the right scrotum.Bilateral involvement was rare.The indication for initial VPS insertion was congenital hydrocephalus in four-fifths of the group A cases.The majority were infants at the time of initial shunt insertion.Four-fifths of the group A cases were 24 months-old or younger at the time of clinical diagnosis and treatment was provided for migration of the distal VPS catheter into the scrotum.In children,the interval from VPS insertion or shunt revision if any,to the diagnosis of the complication mentioned above was 12 months or less in four-fifths of the cases.The repositioning of migrated distal VPS catheter into the peritoneal cavity and herniotomy was preferred for the surgical procedure,and it was performed for two-thirds of group A cases.CONCLUSION Migration of the distal part of the VPS catheter into the scrotum is a rare complication of cerebrospinal fluid diversion via VPS catheter insertion.It was most frequent in children,and the right side of the scrotum was most often involved.展开更多
BACKGROUND Glioblastoma multiforme(GBM)is the most aggressive and prevalent primary malignant brain tumor in adults,marked by poor prognosis and high invasiveness.Traditional GBM invasion assays,such as those involvin...BACKGROUND Glioblastoma multiforme(GBM)is the most aggressive and prevalent primary malignant brain tumor in adults,marked by poor prognosis and high invasiveness.Traditional GBM invasion assays,such as those involving mouse brain xenografts,are often time-consuming and limited in efficiency.In this context,stem cell-derived neural organoids(NOs)have emerged as advanced,threedimensional,human-relevant platforms that mimic the cellular architecture and microenvironment of the human brain.These models provide novel opportunities to investigate glioblastoma stem cell invasion,a critical driver of tumor progression and therapeutic resistance.AIM To evaluate studies using stem cell-derived NOs to model glioblastoma migration/invasion,focusing on methodologies,applications and therapeutic implications.METHODS We conducted a systematic review following PRISMA guidelines,searching PubMed and Scopus for studies published between March 2019 and March 2025 that investigated NOs in the context of glioblastoma invasion/migration.After screening 377 articles based on predefined inclusion and exclusion criteria,10 original research articles were selected for analysis.Extracted data were categorized into four analytical domains:(1)Tumor model formation;(2)NO characteristics;(3)NO differentiation protocols;and(4)Invasion/migration assessment methodologies.RESULTS The included studies exhibit significant methodological heterogeneity GBM model development,particularly regarding model type,cell source and culture conditions.Most studies(70%)used suspension cell models,while 30%employed spheroids,with most research focusing on patient-derived glioblastoma stem cells.NOs were predominantly generated from human induced pluripotent stem cells using both guided and unguided differentiation protocols.Confocal fluorescence microscopy was the primary method used for assessing invasion,revealing invasion depths of up to 300μm.Organoid maturity and co-culture duration influenced results,while key factors for model optimization included tumor cell density,organoid age and extracellular matrix composition.Some studies also tested therapeutic strategies such as Zika virus and microRNA modulation.Collectively,findings support the utility of NOs as effective tools for studying GBM behavior and therapeutic responses in a humanized three-dimensional context.CONCLUSION Human NOs represent promising platforms for modeling glioblastoma invasion in a humanized three-dimensional environment.However,a limited number of studies and methodological heterogeneity hinder reproducibility.Protocol standardization is essential to enhance the translational application of these models.展开更多
Natural photosynthesis,the cornerstone of life on Earth,has long inspired sustainable chemistry by converting solar energy into chemical energy,thereby maintaining atmospheric balance and supporting biological product...Natural photosynthesis,the cornerstone of life on Earth,has long inspired sustainable chemistry by converting solar energy into chemical energy,thereby maintaining atmospheric balance and supporting biological productivity.Mimicking this natural process,photocatalysis has emerged as a promising strategy for harnessing solar energy to drive chemical reactions with minimal environmental impact.This versatile approach finds applications in pollutant degradation,water purification,energy conversion,and organic synthesis.However,a major limitation of single-component photocatalysts is the rapid recombination of photogenerated charge carriers,significantly reducing their efficiency.展开更多
The published article titled“MicroRNA-133b Inhibits Proliferation,Cellular Migration,and Invasion via Targeting LASP1 in Hepatocarcinoma Cells”has been retracted from Oncology Research,Vol.25,No.8,2017,pp.1269–1282.
Adult neurogenesis continuously produces new neurons critical for cognitive plasticity in adult rodents.While it is known transforming growth factor-βsignaling is important in embryonic neurogenesis,its role in postn...Adult neurogenesis continuously produces new neurons critical for cognitive plasticity in adult rodents.While it is known transforming growth factor-βsignaling is important in embryonic neurogenesis,its role in postnatal neurogenesis remains unclear.In this study,to define the precise role of transforming growth factor-βsignaling in postnatal neurogenesis at distinct stages of the neurogenic cascade both in vitro and in vivo,we developed two novel inducible and cell type-specific mouse models to specifically silence transforming growth factor-βsignaling in neural stem cells in(mGFAPcre-ALK5fl/fl-Ai9)or immature neuroblasts in(DCXcreERT2-ALK5fl/fl-Ai9).Our data showed that exogenous transforming growth factor-βtreatment led to inhibition of the proliferation of primary neural stem cells while stimulating their migration.These effects were abolished in activin-like kinase 5(ALK5)knockout primary neural stem cells.Consistent with this,inhibition of transforming growth factor-βsignaling with SB-431542 in wild-type neural stem cells stimulated proliferation while inhibited the migration of neural stem cells.Interestingly,deletion of transforming growth factor-βreceptor in neural stem cells in vivo inhibited the migration of postnatal born neurons in mGFAPcre-ALK5fl/fl-Ai9 mice,while abolishment of transforming growth factor-βsignaling in immature neuroblasts in DCXcreERT2-ALK5fl/fl-Ai9 mice did not affect the migration of these cells in the hippocampus.In summary,our data supports a dual role of transforming growth factor-βsignaling in the proliferation and migration of neural stem cells in vitro.Moreover,our data provides novel insights on cell type-specific-dependent requirements of transforming growth factor-βsignaling on neural stem cell proliferation and migration in vivo.展开更多
In wave-equation migration and demigration,the cross-correlation imaging/forwarding step implicitly injects an additional copy of the source wavelet,so that the amplitude spectrum of the wavelet is applied redundantly...In wave-equation migration and demigration,the cross-correlation imaging/forwarding step implicitly injects an additional copy of the source wavelet,so that the amplitude spectrum of the wavelet is applied redundantly(effectively imposing a wavelet-spectrum weighting,often akin to an amplitude-squared bias).This redundancy degrades structural fidelity and amplitude balance yet is frequently overlooked.We(i)formalize the mechanism by which cross-correlation duplicates the source-wavelet amplitude effect in both migration and demigration,and(ii)introduce a source-equalized operator that removes the redundancy by deconvolving(or dividing by)the wavelet amplitude spectrum in the imaging condition and its demigration counterpart,while leaving phase/kinematics intact.Using a band-limited Ricker wavelet on a two-layer model and on Marmousi,we show that,if unmanaged,the redundant wavelet spectrum broadens main lobes,introduces ringing,and suppresses vertical resolution in migrated images,and inflates spectrum mismatches between demigrated and observed data even when peak times agree.With our correction,images recover observed-data-consistent bandwidth and sharpened interfaces,and demigrated data also exhibit improved spectrum conformity and reduced amplitude misfit.The results clarify when source amplitudes matter,why cross-correlation makes them redundantly matter,and how a lightweight spectral correction restores physically meaningful amplitude behavior in wave-equation migration/demigration.展开更多
Peripheral nerve defect repair is a complex process that involves multiple cell types;perineurial cells play a pivotal role.Hair follicle neural crest stem cells promote perineurial cell proliferation and migration vi...Peripheral nerve defect repair is a complex process that involves multiple cell types;perineurial cells play a pivotal role.Hair follicle neural crest stem cells promote perineurial cell proliferation and migration via paracrine signaling;however,their clinical applications are limited by potential risks such as tumorigenesis and xenogeneic immune rejection,which are similar to the risks associated with other stem cell transplantations.The present study therefore focuses on small extracellular vesicles derived from hair follicle neural crest stem cells,which preserve the bioactive properties of the parent cells while avoiding the transplantation-associated risks.In vitro,small extracellular vesicles derived from hair follicle neural crest stem cells significantly enhanced the proliferation,migration,tube formation,and barrier function of perineurial cells,and subsequently upregulated the expression of tight junction proteins.Furthermore,in a rat model of sciatic nerve defects bridged with silicon tubes,treatment with small extracellular vesicles derived from hair follicle neural crest stem cells resulted in higher tight junction protein expression in perineurial cells,thus facilitating neural tissue regeneration.At 10 weeks post-surgery,rats treated with small extracellular vesicles derived from hair follicle neural crest stem cells exhibited improved nerve function recovery and reduced muscle atrophy.Transcriptomic and micro RNA analyses revealed that small extracellular vesicles derived from hair follicle neural crest stem cells deliver mi R-21-5p,which inhibits mothers against decapentaplegic homolog 7 expression,thereby activating the transforming growth factor-β/mothers against decapentaplegic homolog signaling pathway and upregulating hyaluronan synthase 2 expression,and further enhancing tight junction protein expression.Together,our findings indicate that small extracellular vesicles derived from hair follicle neural crest stem cells promote the proliferation,migration,and tight junction protein formation of perineurial cells.These results provide new insights into peripheral nerve regeneration from the perspective of perineurial cells,and present a novel approach for the clinical treatment of peripheral nerve defects.展开更多
Study was carried out to analyze the distribution and migration patterns,soil-to-plant transfer and potential health risks of chromium in soil-vegetable system in areas near a ferro-alloy manufactory in Hunan province...Study was carried out to analyze the distribution and migration patterns,soil-to-plant transfer and potential health risks of chromium in soil-vegetable system in areas near a ferro-alloy manufactory in Hunan province.The results show that soils near sewer outlet,sewer channel and in control area are averaged 2 239.5,995.33 and 104.9 mg/kg,respectively.The total Cr has a relative accumulation in soil depth of 200-400 mm near the sewer outlet,mainly enriches in the surface layer（0-200 mm） near the sewer channel and decreases gradually in unpolluted soils.The differential concentration level of enrichment between layers is little.The results also indicate that the three vegetables of celery,lettuce and Chinese cabbage are able to convert the potentially toxic Cr（Ⅵ） species into the non-toxic Cr（Ⅲ） species,and the chromium contents in the edible parts of the vegetables are averaged 11.95 mg/kg.The transfer factors of the three vegetables follow the order：Chinese cabbage lettuce celery.The estimated total daily intake of chromium substantially exceeds the dietary allowable value,which may pose health risks to local population.展开更多
Effective migration system of coalbed methane(CBM)reservoir,which was controlled by development degree and opening-closing degree of fractures,determines the permeability of coal reservoir and can be characterized by ...Effective migration system of coalbed methane(CBM)reservoir,which was controlled by development degree and opening-closing degree of fractures,determines the permeability of coal reservoir and can be characterized by the pore-fracture system in the extrinsic form.In this paper,based on coal matrix elastic self-regulating effect theory and coal reservoir combined elastic energy theory,the fracture opening-closing degree parameterΔand the fracture development degree parameterξare suggested for the quantitative study of the effective migration system of CBM reservoir in southern Qinshui Basin.Further,the control functions ofξandΔto CBM enrichment and high production are discussed.The results show that in present stage the area with highξvalue is located in Anze and Qinyuan,and then Zhengzhuang and Fangzhuang,where fracture development degree is high.The area with highΔvalue is located in Zhengzhuang and Fanzhuang,and then Anze and Qinyuan,indicating where coal matrix elastic self-regulating positive effect dominates and fractures tend to be open.Through the comprehensive analysis onξandΔ,it can be found that their best match area is located in Zhengzhuang and Fanzhuang,with high values for fracture development degree and opening-closing degree probably bringing about high fluid pressure and good permeability of reservoirs,which are advantageous to an abundant CBM production.展开更多
The purpose of this essay is to discuss the ＂Lusophone＇＇l media system, inside the ＂Lusophone＂ migration system, from the perspective of data collected in an empirical work. For this purpose, we discuss the conce...The purpose of this essay is to discuss the ＂Lusophone＇＇l media system, inside the ＂Lusophone＂ migration system, from the perspective of data collected in an empirical work. For this purpose, we discuss the concept of ＂Lusophone＂ and ＂Lusophone＂ migration system, and we present the context of immigration in Portugal. The empirical work involved 14 in-depth interviews2 and started by presenting, in broad strokes, some important aspects relating to the history of ＂Lusophone＂. The analysis of the interviews was sustained in the theories of economic and political ＂world-system＂ developed by Braudel （1949） and Wallerstein （2004） and extended to the concept of migration systems of Kritz and Zlotnik （1992）. Their proposals were further developed by the Portuguese sociologist Baganha （2009） who defended the particularity of a ＂Lusophone＂ migration system. Based on those concepts, we describe the theoretical and empirical research and methodological procedures, stressing the trajectories of migration, social mobility and consumption of media and Information Communication Technologies （ICT）. We analyze the interviews, highlighting the similarities and differences, regarding the uses and consumptions of media and ICTs, between Brazilians and Finally based on the results, we discuss the characteristics the citizens from Portuguese-speaking African Countries of this ＂Lusophone＂ media system.展开更多
We investigated migration of pollutant at the base of the Suzhou landfill after it had been operated for 13 years.The investigation was carried out by performing chemical analyses on the soil samples taken from the si...We investigated migration of pollutant at the base of the Suzhou landfill after it had been operated for 13 years.The investigation was carried out by performing chemical analyses on the soil samples taken from the silty clay deposit.Concentrations of chloride,chemical oxygen demand(COD)and the heavy metals in the soil samples were determined using the standard methods.The experimental data showed that the maximum migration depth of chloride was more than 10 m,while the maximum migration depth of COD varied between 1 and 3.5 m.It is believed that the difference is attributed to the variation in diffusion rate and leachate-soil interaction.The chloride profiles also indicated that adveetion may be the dominant contaminant transport mechanism at this site.The total contents ofCu,Pb and Cr are very close to the background levels and the concentration values of these metals mainly are lower than the threshold values specified by the Chinese soil quality standard and the European one.The water-extractable concentrations of COD in the surface of the silty clay generally exceed the limit value specified by the Chinese standard.The concentrations of copper and chromium in pore water are 1-2 orders of magnitude less than the total concentrations of these heavy metals within the soils,implying that heavy metals are mainly adsorbed by the soil particles.Finally,remediation methods were suggested for this landfill site.展开更多
Understanding hydrocarbon migration and accumulation mechanisms is one of the key scientif ic problems that should be solved for effective hydrocarbon exploration in the superimposed basins developed in northwest Chin...Understanding hydrocarbon migration and accumulation mechanisms is one of the key scientif ic problems that should be solved for effective hydrocarbon exploration in the superimposed basins developed in northwest China. The northwest striking No.1 slope break zone, which is a representative of superimposed basins in the Tarim Basin, can be divided into five parts due to the intersection of the northeast strike-slip faults. Controlled by the tectonic framework, the types and properties of reservoirs and the hydrocarbon compositions can also be divided into five parts from east to west. Anomalies of all the parameters were found on the fault intersection zone and weakened up-dip along the structural ridge away from it. Thus, it can be inferred that the intersection zone is the hydrocarbon charging position. This new conclusion differs greatly from the traditional viewpoint, which believes that the hydrocarbon migrates and accumulates along the whole plane of the No.1 slope break zone. The viewpoint is further supported by the evidence from the theory of main pathway systems, obvious improvement of the reservoir quality （2-3 orders of magnitude at the intersection zone） and the formation mechanisms of the fault intersection zone. Differential hydrocarbon migration and entrapment exists in and around the strike- slip faults. This is controlled by the internal structure of faults. It is concluded that the more complicated the fault structure is, the more significant the effects will be. If there is a deformation band, it will hinder the cross fault migration due to the common feature of two to four orders of magnitude reduction in permeability. Otherwise, hydrocarbons tend to accumulate in the up-dip structure under the control of buoyancy. Further research on the internal fault structure should be emphasized.展开更多
Ecological migration is the process of increasing the population density in the immigration area and transferring the ecological pressure from emigration area to immigration area. This process may result in significan...Ecological migration is the process of increasing the population density in the immigration area and transferring the ecological pressure from emigration area to immigration area. This process may result in significant changes in land use and land cover in the area of immigration and have an important effect on ecosystem services. Therefore, scientifically revealing the effects and differentiation mechanisms of ecological migration on ecosystem services is becoming an important issue related to the implementation of the national ecological migration strategy in China. This study employed the Hongsibu District as a typical example of ecological migration. Hongsibu District is located in the central Ningxia steppe and desert steppe areas. Remote sensing data covering five periods from the period before ecological migration in 1995 and after migration in 2000, 2005, 2010, and 2015 was used to measure the value of ecosystem services(ESV). A geographical detector model and the value of ecosystem services model were used to diagnose the dynamic mechanism of the effects of land use change on ecosystem services. The results showed that: 1) The development of large-scale ecological resettlement has caused the area of cultivated land and urbanized land area to increase significantly in the area of immigration, while the grass area decreased significantly. 2) The overall value of the Hongsibu ecosystem services increased in a form of a ‘V'. Among them, during the period of 1995–2005, the overall ESV decreased and had an annual rate of change of-0.67%. During the period of development 2005–2015, the ESV increased steadily, with an annual rate of change of 0.79%. 3) The proportion and total ESV in soil formation and protection, waste treatment, and biodiversity conservation of the Hongsibu District decreased from 57.61% in 1995 to 56.17% in 2015, indicating that the region's ecological regulation function slightly decreased. 4) The ESV in the Hongsibu District, showed a low distribution pattern of ecosystem services increasing from northeast to southwest, and the capacity of three townships, Hongsibu, Taiyangshan, and Liuquan, to provide ecosystem services gradually declined over time. The ecological service function of Xinzhuangji Township and Dahe Township gradually improved. 5) The sensitivity index of the ESV of each land use type was less than 1, indicating that the environment lacks flexibility in providing a strong ESV index in Hongsibu, which shows that the research results are reliable and believable. 6) During the study period, the decisive force of the change of land use on ecosystem services in Hongsibu District was: grassland(0.9934), climate regulation(0.9413), soil formation and protection(0.9321) and waste treatment(0.9241).展开更多
The fault system of Liaodong Bay developed extensively under the control of the Tanlu Fault. The fault system can be grouped into strike-slip faults of grade Ⅰ, trunk faults of grade Ⅱand branch faults （induced fau...The fault system of Liaodong Bay developed extensively under the control of the Tanlu Fault. The fault system can be grouped into strike-slip faults of grade Ⅰ, trunk faults of grade Ⅱand branch faults （induced faults） of grade Ⅲ respectively based on its developmental scale. The faults of grade Ⅰ and Ⅱwere deep, early and large while the faults of grade Ⅲwere shallow, late and small. The formation, evolution and distribution features played a significant role in controlling the migration of oil and gas in both horizontal and vertical directions. The fluid transfer in the fault system occurred in the process of faulting. The strike-slip and trunk faults moved actively forming predominant pathways for oil and gas migration. The branch faults, with weak activity, generally controlled the development of traps and were beneficial for the accumulation and preservation of oil and gas. The faults of grade Ⅰ and Ⅱ formed the major migration pathways for oil and gas, but their fault activity rates appeared to vary along their strikes. The zones with a relatively low fault activity rate might be favorable for oil and gas accumulation. When the activities of strike-slip, trunk, and branch faults came to a halt, the fault seal behavior had a vitally important effect on the accumulation of oil and gas. The controlling role of the fault over fluid distribution was further analyzed by calculating the fault activity quantitatively.展开更多
Percutaneous endoscopic gastrostomy(PEG) is a common practice for long-term nutrition of patients who are unable to take oral food. We report of an 85-year old man with a history of recurrent larynx carcinoma and hemi...Percutaneous endoscopic gastrostomy(PEG) is a common practice for long-term nutrition of patients who are unable to take oral food. We report of an 85-year old man with a history of recurrent larynx carcinoma and hemicolectomy many years ago due to unknown reason. Laryngectomy was indicated. Preoperatively a PEG was inserted endoscopically after an abdominal ultrasonography without abnormal findings. Few months after PEG insertion, the patient was evaluated for diarrhea and insufficient feeding without signs of infection or peritonism. An upper endoscopy and computed tomography scan confirmed a buried bumper syndrome with migration of the PEG tube into the colon as a rare complication. He underwent successful colonoscopic removal of the internal bumper and closure of the colonic orifice of the fistula with the over-the-scope-clip system(OTSC). OTSC is an endoscopic device for treatment of bleeding, perforation, leak and fistula in the gastrointestinal tract. To the best of our knowledge, this is the first report of the use of OTSC for colonoscopic closure of a gastrocolocutaneous fistula due to a buried bumper syndrome with transcolonic PEG tube migration.展开更多
In this paper, incised valley filling deposits, which formed an important pathway system for long-distance hydrocarbon migration, are discussed in detail based on core and logging data. The sequence SQy23 of the Creta...In this paper, incised valley filling deposits, which formed an important pathway system for long-distance hydrocarbon migration, are discussed in detail based on core and logging data. The sequence SQy23 of the Cretaceous Yaojia Formation is the main hydrocarbon-bearing layer in the Fulaerji Oilfield. The hydrocarbon source of the oilfield is the Qijia-Gulong Sag which is about 80 km away from the Fulaerji Oilfield. The transport layer of long-distance hydrocarbon migration is the overlapped sandstone complex which fills the incised valley. The incised valley developed during the depositional period from the late Qingshankou Formation to the early Yaojia Formation of Cretaceous （SQqna-SQy0 was about 70 km long and 20 km wide, and extended in the NW-SE direction. The overlapped filling of the incised valley mainly occurred in the expanding system tract of the third-order sequence SQy23 （ESTy23）. Towards the basin, incised valley filling deposits overlapped on the delta developed in the early period, and towards the basin margin, incised valley filling deposits were covered by the shore-shallow lacustrine sandy beach bar developed in the maximum flooding period. All of the delta, the incised valley filling and the shore-shallow sandy beach bar are sandstone-rich, and have high porosity and permeability, and can form an effective hydrocarbon migration and accumulation system. Deltaic sand bodies collected and pumped hydrocarbon from the active source, incised valley filling depositional system completed the long-distance hydrocarbon migration, and lithological traps of shore-shallow lacustrine sandy beach bar accumulated hydrocarbon. The incised valley filling sequences are multi-cycle： an integrated shortterm filling cycle was developed on the erosion surface, and the sequences upward were mud-gravel stone, medium-fine sandstone containing terrigenous gravels and muddy pebbles with cross bedding, silty mudstone with ripple bedding, and mudstone. The incised valley filling deposits are characterized by a strong heterogeneity and the main hydrocarbon migration pathway is the medium-fine sandstone interval.展开更多
Since the concept of petroleum migration-accumulation dynamic system （PMADS） was introduced in the 1990s, its definition, division and even denomination have long been in disagreement. This article aims to further d...Since the concept of petroleum migration-accumulation dynamic system （PMADS） was introduced in the 1990s, its definition, division and even denomination have long been in disagreement. This article aims to further discuss and try to clarify this concept and to explore more reasonable approaches to the division of PMADSs on the basis of our studies on petroleum migration and accumulation in some pe- troliferous basins of China, especially those from western China. According to the studies, we define PMADS as a relatively independent natural hydrocarbon migrating and accumulating system within a petroleum system. Its extent is supposed to cover the whole migration pathway starting from a hydrocarbon provenance throughout to an accumulation or a group of accumulations of same source. Just like petroleum systems, a petroleum migration-accumulation system is also an important natural unit for petroleum exploration and assessment in petroleum basins. Its position in a basin is right between a petroleum system and a play. A pe- troleum system has either a number of migration-accumulation systems or one system only. However, the key element of a petroleum system is the source of hydrocarbon; a petroleum system has a distinct hydrocarbon kitchen and is different from its neighboring ones in terms of hydrocarbon kitchens. In contrast, different migration-accumulation systems within the same petroleum system have a shared source kitchen but differ-ent characteristics of migration and accumulation to form hydrocarbon accumulations. As far as the division of petroleum migration-accumulation systems （PMASs） is concerned, 8 major approaches are proposed, including those based on pool-forming dynamic mechanisms, location of hydrocarbon accumulation rela- tive to the source kitchen, phase states of migration and accumulation, migration patterns and directions, geneses of accumulations, reservoir pressure systems, depositional systems and facies, and integrated method, of which the integrated approach is underlined with regard to the division of PMASs in a com-plex petroleum system like those in West-China superimposed basins.展开更多
Migration is ubiquitous in ecosystem and often plays an important role in biological diversity. In this work,by introducing a time-varying migration rate associated with the difference of subpopulation density into a ...Migration is ubiquitous in ecosystem and often plays an important role in biological diversity. In this work,by introducing a time-varying migration rate associated with the difference of subpopulation density into a prey, we study the Hopf bifurcation and the critical phenomenon of predator extinction of the three species prey-predator system,which consists of a predator, a prey and a mobile prey. It is found that the system with migration exhibits richer dynamic behaviors than that without migration, including two Hopf bifurcations and two limit cycles. Interestingly,the parameters of migration have a drastically influence on the critical point of predator extinction, determining the coexistence of species. Moreover, the population evolution dynamics of one-dimensional multiple prey-predator system are also discussed.展开更多
This paper describes systematic measurement of fiber migration and distribution pattern of twist at different radial positions of rotor spun yarn mixed tracer fiber by Hi-Scope Video Microscope System. The positions o...This paper describes systematic measurement of fiber migration and distribution pattern of twist at different radial positions of rotor spun yarn mixed tracer fiber by Hi-Scope Video Microscope System. The positions of tracer fibers were measured in three dimensions accurately, and the migration index and the twist distribution at different radial positions of rotor yarn were calculated and analyzed. This research result serves to provide useful references for further study on the structural mechanics of rotor spun yarn.展开更多
The global outbreak of coronavirus infectious disease-2019(COVID-19)draws attentions in the transport and spread of Severe Acute Respiratory Syndrome Coronavirus 2(SARS-CoV-2)in aerosols,wastewater,surface water and s...The global outbreak of coronavirus infectious disease-2019(COVID-19)draws attentions in the transport and spread of Severe Acute Respiratory Syndrome Coronavirus 2(SARS-CoV-2)in aerosols,wastewater,surface water and solid wastes.As pathogens eventually enter the subsurface system,e.g.,soils in the vadose zone and groundwater in the aquifers,they might survive for a prolonged period of time owing to the uniqueness of subsurface environment.In addition,pathogens can transport in groundwater and contaminate surrounding drinking water sources,possessing long-term and concealed risks to human society.This work critically reviews the influential factors of pathogen migration,unravelling the impacts of pathogenic characteristics,vadose zone physiochemical properties and hydrological variables on the migration of typical pathogens in subsurface system.An assessment algorithm and two rating/weighting schemes are proposed to evaluate the migration abilities and risks of pathogens in subsurface environment.As there is still no evidence about the presence and distribution of SARS-CoV-2 in the vadose zones and aquifers,this study also discusses the migration potential and behavior of SARS-CoV-2 viruses in subsurface environment,offering prospective clues and suggestions for its potential risks in drinking water and effective prevention and control from hydrogeological points of view.展开更多
文摘BACKGROUND Ventriculoperitoneal shunt(VPS)catheter insertion is one of the most widely accepted surgical procedures for hydrocephalus.Migration of the end of the distal VPS catheter into the scrotum is one of the rare complications of VPS catheter insertion.METHODS This is a systematic review of the published cases,and the literature search was performed from 1974 to June 30,2024,to retrieve the relevant manuscripts.The cases were grouped into two.Group A included cases of migration of the distal VPS catheter into the scrotum,detected in children.Group B included the cases of migration of the distal VPS catheter into the scrotum,which was detected in adults and older people.RESULTS One hundred-twenty cases of migration of the distal end of VPS catheter into the scrotum were included in this study,a systematic literature review.Group A included n=112 cases,and group B included n=8 cases only.Three-fourths of the cases involved the right scrotum.Bilateral involvement was rare.The indication for initial VPS insertion was congenital hydrocephalus in four-fifths of the group A cases.The majority were infants at the time of initial shunt insertion.Four-fifths of the group A cases were 24 months-old or younger at the time of clinical diagnosis and treatment was provided for migration of the distal VPS catheter into the scrotum.In children,the interval from VPS insertion or shunt revision if any,to the diagnosis of the complication mentioned above was 12 months or less in four-fifths of the cases.The repositioning of migrated distal VPS catheter into the peritoneal cavity and herniotomy was preferred for the surgical procedure,and it was performed for two-thirds of group A cases.CONCLUSION Migration of the distal part of the VPS catheter into the scrotum is a rare complication of cerebrospinal fluid diversion via VPS catheter insertion.It was most frequent in children,and the right side of the scrotum was most often involved.
基金Supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico,No.307318/2023-0 and No.102035/2024-5Fundação de AmparoàPesquisa do Estado de São Paulo,No.2023/10843-7 and No 2019/21070-3Nanotechnology National Laboratory System 2.0,Ministry of Science,Technology,Innovation and Communication,No.442539/2019-3.
文摘BACKGROUND Glioblastoma multiforme(GBM)is the most aggressive and prevalent primary malignant brain tumor in adults,marked by poor prognosis and high invasiveness.Traditional GBM invasion assays,such as those involving mouse brain xenografts,are often time-consuming and limited in efficiency.In this context,stem cell-derived neural organoids(NOs)have emerged as advanced,threedimensional,human-relevant platforms that mimic the cellular architecture and microenvironment of the human brain.These models provide novel opportunities to investigate glioblastoma stem cell invasion,a critical driver of tumor progression and therapeutic resistance.AIM To evaluate studies using stem cell-derived NOs to model glioblastoma migration/invasion,focusing on methodologies,applications and therapeutic implications.METHODS We conducted a systematic review following PRISMA guidelines,searching PubMed and Scopus for studies published between March 2019 and March 2025 that investigated NOs in the context of glioblastoma invasion/migration.After screening 377 articles based on predefined inclusion and exclusion criteria,10 original research articles were selected for analysis.Extracted data were categorized into four analytical domains:(1)Tumor model formation;(2)NO characteristics;(3)NO differentiation protocols;and(4)Invasion/migration assessment methodologies.RESULTS The included studies exhibit significant methodological heterogeneity GBM model development,particularly regarding model type,cell source and culture conditions.Most studies(70%)used suspension cell models,while 30%employed spheroids,with most research focusing on patient-derived glioblastoma stem cells.NOs were predominantly generated from human induced pluripotent stem cells using both guided and unguided differentiation protocols.Confocal fluorescence microscopy was the primary method used for assessing invasion,revealing invasion depths of up to 300μm.Organoid maturity and co-culture duration influenced results,while key factors for model optimization included tumor cell density,organoid age and extracellular matrix composition.Some studies also tested therapeutic strategies such as Zika virus and microRNA modulation.Collectively,findings support the utility of NOs as effective tools for studying GBM behavior and therapeutic responses in a humanized three-dimensional context.CONCLUSION Human NOs represent promising platforms for modeling glioblastoma invasion in a humanized three-dimensional environment.However,a limited number of studies and methodological heterogeneity hinder reproducibility.Protocol standardization is essential to enhance the translational application of these models.
文摘Natural photosynthesis,the cornerstone of life on Earth,has long inspired sustainable chemistry by converting solar energy into chemical energy,thereby maintaining atmospheric balance and supporting biological productivity.Mimicking this natural process,photocatalysis has emerged as a promising strategy for harnessing solar energy to drive chemical reactions with minimal environmental impact.This versatile approach finds applications in pollutant degradation,water purification,energy conversion,and organic synthesis.However,a major limitation of single-component photocatalysts is the rapid recombination of photogenerated charge carriers,significantly reducing their efficiency.
文摘The published article titled“MicroRNA-133b Inhibits Proliferation,Cellular Migration,and Invasion via Targeting LASP1 in Hepatocarcinoma Cells”has been retracted from Oncology Research,Vol.25,No.8,2017,pp.1269–1282.
基金supported by NIH grants,Nos.R01NS125074,R01AG083164,R01NS107365,and R21NS127177(to YL),1F31NS129204-01A1(to KW)and Albert Ryan Fellowship(to KW).
文摘Adult neurogenesis continuously produces new neurons critical for cognitive plasticity in adult rodents.While it is known transforming growth factor-βsignaling is important in embryonic neurogenesis,its role in postnatal neurogenesis remains unclear.In this study,to define the precise role of transforming growth factor-βsignaling in postnatal neurogenesis at distinct stages of the neurogenic cascade both in vitro and in vivo,we developed two novel inducible and cell type-specific mouse models to specifically silence transforming growth factor-βsignaling in neural stem cells in(mGFAPcre-ALK5fl/fl-Ai9)or immature neuroblasts in(DCXcreERT2-ALK5fl/fl-Ai9).Our data showed that exogenous transforming growth factor-βtreatment led to inhibition of the proliferation of primary neural stem cells while stimulating their migration.These effects were abolished in activin-like kinase 5(ALK5)knockout primary neural stem cells.Consistent with this,inhibition of transforming growth factor-βsignaling with SB-431542 in wild-type neural stem cells stimulated proliferation while inhibited the migration of neural stem cells.Interestingly,deletion of transforming growth factor-βreceptor in neural stem cells in vivo inhibited the migration of postnatal born neurons in mGFAPcre-ALK5fl/fl-Ai9 mice,while abolishment of transforming growth factor-βsignaling in immature neuroblasts in DCXcreERT2-ALK5fl/fl-Ai9 mice did not affect the migration of these cells in the hippocampus.In summary,our data supports a dual role of transforming growth factor-βsignaling in the proliferation and migration of neural stem cells in vitro.Moreover,our data provides novel insights on cell type-specific-dependent requirements of transforming growth factor-βsignaling on neural stem cell proliferation and migration in vivo.
基金supported by the National Natural Science Foundation of China(42430303)Strategy Priority Research Program(Category B)of the Chinese Academy of Sciences(XDB0710000)+2 种基金National Natural Science Foundation of China(42288201)the National Key R&D Program of China(2023YFF0803203)the IGGCAS start-up funding(Grant No.E251510101).
文摘In wave-equation migration and demigration,the cross-correlation imaging/forwarding step implicitly injects an additional copy of the source wavelet,so that the amplitude spectrum of the wavelet is applied redundantly(effectively imposing a wavelet-spectrum weighting,often akin to an amplitude-squared bias).This redundancy degrades structural fidelity and amplitude balance yet is frequently overlooked.We(i)formalize the mechanism by which cross-correlation duplicates the source-wavelet amplitude effect in both migration and demigration,and(ii)introduce a source-equalized operator that removes the redundancy by deconvolving(or dividing by)the wavelet amplitude spectrum in the imaging condition and its demigration counterpart,while leaving phase/kinematics intact.Using a band-limited Ricker wavelet on a two-layer model and on Marmousi,we show that,if unmanaged,the redundant wavelet spectrum broadens main lobes,introduces ringing,and suppresses vertical resolution in migrated images,and inflates spectrum mismatches between demigrated and observed data even when peak times agree.With our correction,images recover observed-data-consistent bandwidth and sharpened interfaces,and demigrated data also exhibit improved spectrum conformity and reduced amplitude misfit.The results clarify when source amplitudes matter,why cross-correlation makes them redundantly matter,and how a lightweight spectral correction restores physically meaningful amplitude behavior in wave-equation migration/demigration.
基金supported by the National Natural Science Foundation of China,No.81571211(to FL)the Natural Science Foundation of Shanghai,No.22ZR1476800(to CH)。
文摘Peripheral nerve defect repair is a complex process that involves multiple cell types;perineurial cells play a pivotal role.Hair follicle neural crest stem cells promote perineurial cell proliferation and migration via paracrine signaling;however,their clinical applications are limited by potential risks such as tumorigenesis and xenogeneic immune rejection,which are similar to the risks associated with other stem cell transplantations.The present study therefore focuses on small extracellular vesicles derived from hair follicle neural crest stem cells,which preserve the bioactive properties of the parent cells while avoiding the transplantation-associated risks.In vitro,small extracellular vesicles derived from hair follicle neural crest stem cells significantly enhanced the proliferation,migration,tube formation,and barrier function of perineurial cells,and subsequently upregulated the expression of tight junction proteins.Furthermore,in a rat model of sciatic nerve defects bridged with silicon tubes,treatment with small extracellular vesicles derived from hair follicle neural crest stem cells resulted in higher tight junction protein expression in perineurial cells,thus facilitating neural tissue regeneration.At 10 weeks post-surgery,rats treated with small extracellular vesicles derived from hair follicle neural crest stem cells exhibited improved nerve function recovery and reduced muscle atrophy.Transcriptomic and micro RNA analyses revealed that small extracellular vesicles derived from hair follicle neural crest stem cells deliver mi R-21-5p,which inhibits mothers against decapentaplegic homolog 7 expression,thereby activating the transforming growth factor-β/mothers against decapentaplegic homolog signaling pathway and upregulating hyaluronan synthase 2 expression,and further enhancing tight junction protein expression.Together,our findings indicate that small extracellular vesicles derived from hair follicle neural crest stem cells promote the proliferation,migration,and tight junction protein formation of perineurial cells.These results provide new insights into peripheral nerve regeneration from the perspective of perineurial cells,and present a novel approach for the clinical treatment of peripheral nerve defects.
基金Project (2009ZX07212-001-01) supported by the Key Project of National Natural Science Foundation for Water Pollution Control and RemediationProject (50925417) supported by the National Funds for Distinguished Young Scientists+1 种基金Project (50830301) supported by the National Natural Science Foundation of ChinaProject (51074191) supported by the National Natural Science Foundation of China
文摘Study was carried out to analyze the distribution and migration patterns,soil-to-plant transfer and potential health risks of chromium in soil-vegetable system in areas near a ferro-alloy manufactory in Hunan province.The results show that soils near sewer outlet,sewer channel and in control area are averaged 2 239.5,995.33 and 104.9 mg/kg,respectively.The total Cr has a relative accumulation in soil depth of 200-400 mm near the sewer outlet,mainly enriches in the surface layer（0-200 mm） near the sewer channel and decreases gradually in unpolluted soils.The differential concentration level of enrichment between layers is little.The results also indicate that the three vegetables of celery,lettuce and Chinese cabbage are able to convert the potentially toxic Cr（Ⅵ） species into the non-toxic Cr（Ⅲ） species,and the chromium contents in the edible parts of the vegetables are averaged 11.95 mg/kg.The transfer factors of the three vegetables follow the order：Chinese cabbage lettuce celery.The estimated total daily intake of chromium substantially exceeds the dietary allowable value,which may pose health risks to local population.
基金jointly supported by National Natural Science Foundation of China(Grant No.41272178)the Major Projects of National Science and Technology of China(Grant No.2011ZX05034)+1 种基金National Basic Research Program of China(Grant No.2009CB219605)"Qinglan"Project of Jiangsu Province
文摘Effective migration system of coalbed methane(CBM)reservoir,which was controlled by development degree and opening-closing degree of fractures,determines the permeability of coal reservoir and can be characterized by the pore-fracture system in the extrinsic form.In this paper,based on coal matrix elastic self-regulating effect theory and coal reservoir combined elastic energy theory,the fracture opening-closing degree parameterΔand the fracture development degree parameterξare suggested for the quantitative study of the effective migration system of CBM reservoir in southern Qinshui Basin.Further,the control functions ofξandΔto CBM enrichment and high production are discussed.The results show that in present stage the area with highξvalue is located in Anze and Qinyuan,and then Zhengzhuang and Fangzhuang,where fracture development degree is high.The area with highΔvalue is located in Zhengzhuang and Fanzhuang,and then Anze and Qinyuan,indicating where coal matrix elastic self-regulating positive effect dominates and fractures tend to be open.Through the comprehensive analysis onξandΔ,it can be found that their best match area is located in Zhengzhuang and Fanzhuang,with high values for fracture development degree and opening-closing degree probably bringing about high fluid pressure and good permeability of reservoirs,which are advantageous to an abundant CBM production.
文摘The purpose of this essay is to discuss the ＂Lusophone＇＇l media system, inside the ＂Lusophone＂ migration system, from the perspective of data collected in an empirical work. For this purpose, we discuss the concept of ＂Lusophone＂ and ＂Lusophone＂ migration system, and we present the context of immigration in Portugal. The empirical work involved 14 in-depth interviews2 and started by presenting, in broad strokes, some important aspects relating to the history of ＂Lusophone＂. The analysis of the interviews was sustained in the theories of economic and political ＂world-system＂ developed by Braudel （1949） and Wallerstein （2004） and extended to the concept of migration systems of Kritz and Zlotnik （1992）. Their proposals were further developed by the Portuguese sociologist Baganha （2009） who defended the particularity of a ＂Lusophone＂ migration system. Based on those concepts, we describe the theoretical and empirical research and methodological procedures, stressing the trajectories of migration, social mobility and consumption of media and Information Communication Technologies （ICT）. We analyze the interviews, highlighting the similarities and differences, regarding the uses and consumptions of media and ICTs, between Brazilians and Finally based on the results, we discuss the characteristics the citizens from Portuguese-speaking African Countries of this ＂Lusophone＂ media system.
基金supported by the National Natural Science Foundation of China(No.50538080)the National Science Fund for Distinguished Young Scholars(No.50425825),China
文摘We investigated migration of pollutant at the base of the Suzhou landfill after it had been operated for 13 years.The investigation was carried out by performing chemical analyses on the soil samples taken from the silty clay deposit.Concentrations of chloride,chemical oxygen demand(COD)and the heavy metals in the soil samples were determined using the standard methods.The experimental data showed that the maximum migration depth of chloride was more than 10 m,while the maximum migration depth of COD varied between 1 and 3.5 m.It is believed that the difference is attributed to the variation in diffusion rate and leachate-soil interaction.The chloride profiles also indicated that adveetion may be the dominant contaminant transport mechanism at this site.The total contents ofCu,Pb and Cr are very close to the background levels and the concentration values of these metals mainly are lower than the threshold values specified by the Chinese soil quality standard and the European one.The water-extractable concentrations of COD in the surface of the silty clay generally exceed the limit value specified by the Chinese standard.The concentrations of copper and chromium in pore water are 1-2 orders of magnitude less than the total concentrations of these heavy metals within the soils,implying that heavy metals are mainly adsorbed by the soil particles.Finally,remediation methods were suggested for this landfill site.
基金supported by the National 973 Basic Research Program (Grant No.2006CB202308)the Major National Science & Technology Program (2008ZX05008-004-012)
文摘Understanding hydrocarbon migration and accumulation mechanisms is one of the key scientif ic problems that should be solved for effective hydrocarbon exploration in the superimposed basins developed in northwest China. The northwest striking No.1 slope break zone, which is a representative of superimposed basins in the Tarim Basin, can be divided into five parts due to the intersection of the northeast strike-slip faults. Controlled by the tectonic framework, the types and properties of reservoirs and the hydrocarbon compositions can also be divided into five parts from east to west. Anomalies of all the parameters were found on the fault intersection zone and weakened up-dip along the structural ridge away from it. Thus, it can be inferred that the intersection zone is the hydrocarbon charging position. This new conclusion differs greatly from the traditional viewpoint, which believes that the hydrocarbon migrates and accumulates along the whole plane of the No.1 slope break zone. The viewpoint is further supported by the evidence from the theory of main pathway systems, obvious improvement of the reservoir quality （2-3 orders of magnitude at the intersection zone） and the formation mechanisms of the fault intersection zone. Differential hydrocarbon migration and entrapment exists in and around the strike- slip faults. This is controlled by the internal structure of faults. It is concluded that the more complicated the fault structure is, the more significant the effects will be. If there is a deformation band, it will hinder the cross fault migration due to the common feature of two to four orders of magnitude reduction in permeability. Otherwise, hydrocarbons tend to accumulate in the up-dip structure under the control of buoyancy. Further research on the internal fault structure should be emphasized.
基金Under the auspices of the National Natural Science Foundation of China(No.41461039)
文摘Ecological migration is the process of increasing the population density in the immigration area and transferring the ecological pressure from emigration area to immigration area. This process may result in significant changes in land use and land cover in the area of immigration and have an important effect on ecosystem services. Therefore, scientifically revealing the effects and differentiation mechanisms of ecological migration on ecosystem services is becoming an important issue related to the implementation of the national ecological migration strategy in China. This study employed the Hongsibu District as a typical example of ecological migration. Hongsibu District is located in the central Ningxia steppe and desert steppe areas. Remote sensing data covering five periods from the period before ecological migration in 1995 and after migration in 2000, 2005, 2010, and 2015 was used to measure the value of ecosystem services(ESV). A geographical detector model and the value of ecosystem services model were used to diagnose the dynamic mechanism of the effects of land use change on ecosystem services. The results showed that: 1) The development of large-scale ecological resettlement has caused the area of cultivated land and urbanized land area to increase significantly in the area of immigration, while the grass area decreased significantly. 2) The overall value of the Hongsibu ecosystem services increased in a form of a ‘V'. Among them, during the period of 1995–2005, the overall ESV decreased and had an annual rate of change of-0.67%. During the period of development 2005–2015, the ESV increased steadily, with an annual rate of change of 0.79%. 3) The proportion and total ESV in soil formation and protection, waste treatment, and biodiversity conservation of the Hongsibu District decreased from 57.61% in 1995 to 56.17% in 2015, indicating that the region's ecological regulation function slightly decreased. 4) The ESV in the Hongsibu District, showed a low distribution pattern of ecosystem services increasing from northeast to southwest, and the capacity of three townships, Hongsibu, Taiyangshan, and Liuquan, to provide ecosystem services gradually declined over time. The ecological service function of Xinzhuangji Township and Dahe Township gradually improved. 5) The sensitivity index of the ESV of each land use type was less than 1, indicating that the environment lacks flexibility in providing a strong ESV index in Hongsibu, which shows that the research results are reliable and believable. 6) During the study period, the decisive force of the change of land use on ecosystem services in Hongsibu District was: grassland(0.9934), climate regulation(0.9413), soil formation and protection(0.9321) and waste treatment(0.9241).
文摘The fault system of Liaodong Bay developed extensively under the control of the Tanlu Fault. The fault system can be grouped into strike-slip faults of grade Ⅰ, trunk faults of grade Ⅱand branch faults （induced faults） of grade Ⅲ respectively based on its developmental scale. The faults of grade Ⅰ and Ⅱwere deep, early and large while the faults of grade Ⅲwere shallow, late and small. The formation, evolution and distribution features played a significant role in controlling the migration of oil and gas in both horizontal and vertical directions. The fluid transfer in the fault system occurred in the process of faulting. The strike-slip and trunk faults moved actively forming predominant pathways for oil and gas migration. The branch faults, with weak activity, generally controlled the development of traps and were beneficial for the accumulation and preservation of oil and gas. The faults of grade Ⅰ and Ⅱ formed the major migration pathways for oil and gas, but their fault activity rates appeared to vary along their strikes. The zones with a relatively low fault activity rate might be favorable for oil and gas accumulation. When the activities of strike-slip, trunk, and branch faults came to a halt, the fault seal behavior had a vitally important effect on the accumulation of oil and gas. The controlling role of the fault over fluid distribution was further analyzed by calculating the fault activity quantitatively.
文摘Percutaneous endoscopic gastrostomy(PEG) is a common practice for long-term nutrition of patients who are unable to take oral food. We report of an 85-year old man with a history of recurrent larynx carcinoma and hemicolectomy many years ago due to unknown reason. Laryngectomy was indicated. Preoperatively a PEG was inserted endoscopically after an abdominal ultrasonography without abnormal findings. Few months after PEG insertion, the patient was evaluated for diarrhea and insufficient feeding without signs of infection or peritonism. An upper endoscopy and computed tomography scan confirmed a buried bumper syndrome with migration of the PEG tube into the colon as a rare complication. He underwent successful colonoscopic removal of the internal bumper and closure of the colonic orifice of the fistula with the over-the-scope-clip system(OTSC). OTSC is an endoscopic device for treatment of bleeding, perforation, leak and fistula in the gastrointestinal tract. To the best of our knowledge, this is the first report of the use of OTSC for colonoscopic closure of a gastrocolocutaneous fistula due to a buried bumper syndrome with transcolonic PEG tube migration.
文摘In this paper, incised valley filling deposits, which formed an important pathway system for long-distance hydrocarbon migration, are discussed in detail based on core and logging data. The sequence SQy23 of the Cretaceous Yaojia Formation is the main hydrocarbon-bearing layer in the Fulaerji Oilfield. The hydrocarbon source of the oilfield is the Qijia-Gulong Sag which is about 80 km away from the Fulaerji Oilfield. The transport layer of long-distance hydrocarbon migration is the overlapped sandstone complex which fills the incised valley. The incised valley developed during the depositional period from the late Qingshankou Formation to the early Yaojia Formation of Cretaceous （SQqna-SQy0 was about 70 km long and 20 km wide, and extended in the NW-SE direction. The overlapped filling of the incised valley mainly occurred in the expanding system tract of the third-order sequence SQy23 （ESTy23）. Towards the basin, incised valley filling deposits overlapped on the delta developed in the early period, and towards the basin margin, incised valley filling deposits were covered by the shore-shallow lacustrine sandy beach bar developed in the maximum flooding period. All of the delta, the incised valley filling and the shore-shallow sandy beach bar are sandstone-rich, and have high porosity and permeability, and can form an effective hydrocarbon migration and accumulation system. Deltaic sand bodies collected and pumped hydrocarbon from the active source, incised valley filling depositional system completed the long-distance hydrocarbon migration, and lithological traps of shore-shallow lacustrine sandy beach bar accumulated hydrocarbon. The incised valley filling sequences are multi-cycle： an integrated shortterm filling cycle was developed on the erosion surface, and the sequences upward were mud-gravel stone, medium-fine sandstone containing terrigenous gravels and muddy pebbles with cross bedding, silty mudstone with ripple bedding, and mudstone. The incised valley filling deposits are characterized by a strong heterogeneity and the main hydrocarbon migration pathway is the medium-fine sandstone interval.
基金supported by the Key Project of Science and Technology of China (No. 2011ZX05007-004)
文摘Since the concept of petroleum migration-accumulation dynamic system （PMADS） was introduced in the 1990s, its definition, division and even denomination have long been in disagreement. This article aims to further discuss and try to clarify this concept and to explore more reasonable approaches to the division of PMADSs on the basis of our studies on petroleum migration and accumulation in some pe- troliferous basins of China, especially those from western China. According to the studies, we define PMADS as a relatively independent natural hydrocarbon migrating and accumulating system within a petroleum system. Its extent is supposed to cover the whole migration pathway starting from a hydrocarbon provenance throughout to an accumulation or a group of accumulations of same source. Just like petroleum systems, a petroleum migration-accumulation system is also an important natural unit for petroleum exploration and assessment in petroleum basins. Its position in a basin is right between a petroleum system and a play. A pe- troleum system has either a number of migration-accumulation systems or one system only. However, the key element of a petroleum system is the source of hydrocarbon; a petroleum system has a distinct hydrocarbon kitchen and is different from its neighboring ones in terms of hydrocarbon kitchens. In contrast, different migration-accumulation systems within the same petroleum system have a shared source kitchen but differ-ent characteristics of migration and accumulation to form hydrocarbon accumulations. As far as the division of petroleum migration-accumulation systems （PMASs） is concerned, 8 major approaches are proposed, including those based on pool-forming dynamic mechanisms, location of hydrocarbon accumulation rela- tive to the source kitchen, phase states of migration and accumulation, migration patterns and directions, geneses of accumulations, reservoir pressure systems, depositional systems and facies, and integrated method, of which the integrated approach is underlined with regard to the division of PMASs in a com-plex petroleum system like those in West-China superimposed basins.
基金Supported by the National Natural Science Foundation of China under Grant No.11475003the Key project of cultivation of leading talents in Universities of Anhui Provence under Grant Nos.gxfxZD2016174,gxbjZD2016014the project of Academic and technical leaders candidate of Anhui Province under Grant No.2017H117
文摘Migration is ubiquitous in ecosystem and often plays an important role in biological diversity. In this work,by introducing a time-varying migration rate associated with the difference of subpopulation density into a prey, we study the Hopf bifurcation and the critical phenomenon of predator extinction of the three species prey-predator system,which consists of a predator, a prey and a mobile prey. It is found that the system with migration exhibits richer dynamic behaviors than that without migration, including two Hopf bifurcations and two limit cycles. Interestingly,the parameters of migration have a drastically influence on the critical point of predator extinction, determining the coexistence of species. Moreover, the population evolution dynamics of one-dimensional multiple prey-predator system are also discussed.
文摘This paper describes systematic measurement of fiber migration and distribution pattern of twist at different radial positions of rotor spun yarn mixed tracer fiber by Hi-Scope Video Microscope System. The positions of tracer fibers were measured in three dimensions accurately, and the migration index and the twist distribution at different radial positions of rotor yarn were calculated and analyzed. This research result serves to provide useful references for further study on the structural mechanics of rotor spun yarn.
基金financially supported by the National Science Foundation of China(Grant No.52091543)the support of Chinese Government’s Thousand Talents Plan for Young Professionals。
文摘The global outbreak of coronavirus infectious disease-2019(COVID-19)draws attentions in the transport and spread of Severe Acute Respiratory Syndrome Coronavirus 2(SARS-CoV-2)in aerosols,wastewater,surface water and solid wastes.As pathogens eventually enter the subsurface system,e.g.,soils in the vadose zone and groundwater in the aquifers,they might survive for a prolonged period of time owing to the uniqueness of subsurface environment.In addition,pathogens can transport in groundwater and contaminate surrounding drinking water sources,possessing long-term and concealed risks to human society.This work critically reviews the influential factors of pathogen migration,unravelling the impacts of pathogenic characteristics,vadose zone physiochemical properties and hydrological variables on the migration of typical pathogens in subsurface system.An assessment algorithm and two rating/weighting schemes are proposed to evaluate the migration abilities and risks of pathogens in subsurface environment.As there is still no evidence about the presence and distribution of SARS-CoV-2 in the vadose zones and aquifers,this study also discusses the migration potential and behavior of SARS-CoV-2 viruses in subsurface environment,offering prospective clues and suggestions for its potential risks in drinking water and effective prevention and control from hydrogeological points of view.
