During the 1950s the Hula wetlands and old lake were drained and the land converted utilization to agriculture and ecotourism. As a result of the drainage, the Peat Soil was exposed to atmospheric oxygen. The geochemi...During the 1950s the Hula wetlands and old lake were drained and the land converted utilization to agriculture and ecotourism. As a result of the drainage, the Peat Soil was exposed to atmospheric oxygen. The geochemical environment was modified from reductive to oxidative and the Nitrogen in it was converted from Ammonium to Nitrate. Intensive migration of Nitrate from the Hula Valley induced a national concern of water quality deterioration in the lake which was dissipated when Nitrogen deficiency was developed in Lake Kinneret. Forty years after drainage the ecosystem structure was renovated (Hula Project, HP) aimed at agricultural management and nutrient migration reduction. The paper examines through evaluation of the ecological data record (1993-2018) the impact of hydrological changes, attributed to the HP implementation on nutrient dynamics within surface waters in the Hula Valley. It is suggested that soil moisture elevation by irrigation in summer reduced Phosphorus and enhanced Nitrate concentrations.展开更多
The behavior of oil and water in tight rocks can change the distribution of oil or water in pores,which affects the production of crude oil.Nuclear Magnetic Resonance(NMR)method is an effective and nondestructive tool...The behavior of oil and water in tight rocks can change the distribution of oil or water in pores,which affects the production of crude oil.Nuclear Magnetic Resonance(NMR)method is an effective and nondestructive tool for evaluating rocks with comparison and analysis both quantitatively and qualitatively.In our study,20 MHz NMR Relaxometry is used as a key technique to study the changes of water and oil behaviors in Chinese lacustrine Qingshankou shales under different saturated states(imbibition and evaporation without pressure).The results show that variation in different proton populations(water,oil and organic)can be distinguished using 2D T_(1)-T_(2)maps.The comparison among T_(1)-T_(2)maps with different saturated states shows that different signal regions changed during oil and water migrations,which the 1D NMR Relaxometry may be not easy to approach.Combined with the pyrolysis analysis,T2 shift and differences of signal regions in T_(1)-T_(2)maps can reflect properties such as wettability and composition(organic matter,clay and magnetic minerals)to some extent.This study provides better insight into oil and water behaviors in lacustrine oil shales with further understanding of 20 MHz NMR 2D T_(1)-T_(2)maps both in qualitative and quantitative analysis.展开更多
Fuel accumulation, mainly as fatty acids, is one of the main characteristics of migratory, birds. Studying to what extent each population or species manages fuel load and how it varies along routes of migration or bet...Fuel accumulation, mainly as fatty acids, is one of the main characteristics of migratory, birds. Studying to what extent each population or species manages fuel load and how it varies along routes of migration or between seasons (autumn and spring migrations) is crucial to our understanding of bird migration strategies. Our aim here was to analyse whether migratory blackcaps Sylvia atrieapilla passing through northern Iberia differ in their mean fuel loads, rate of fuel accumulation and ' potential' flight ranges between migration seasons. Blackcaps were mist netted for 4 h-periods beginning at dawn from 16 September to 15 November 2003 - 2005, and from 1 March to 30 April 2004 - 2006 in a European Atlantic hedgerow at Loza, northern Iberia. Both fuel load and fuel deposition rate (this latter assessed with difference in body mass of within-season recaptured individuals) were higher in autumn than in spring. Possible hypotheses explaining these results could be seasonal-associated variations in food availability (likely lower during spring than during autumn), the fact that a fraction of the migrants captured in spring could breed close to the study area and different selective pressures for breeding and wintering展开更多
Mass aggregations and migrations of millipedes despite numerous attempts to find causes for their occurrences are still an enigma. They have been reported from both southern and northern hemisphere countries, from hig...Mass aggregations and migrations of millipedes despite numerous attempts to find causes for their occurrences are still an enigma. They have been reported from both southern and northern hemisphere countries, from highlands and lowlands of both tropical and temperate regions and they can involve species belonging to the orders Julida and Spirobolida, Polydesmida and Glomerida. According to the main suggestions put forward in the past, mass occurrences in Diplopoda occur:(1) because of a lack of food and a population increase beyond sustainable levels;(2) for the purpose of reproduction and in order to locate suitable oviposition sites;(3) to find overwintering or aestivation sites;(4) because of habitat disruption and changes in the local environment;(5) as a consequence of weather conditions the year(or winter and spring) before. A recent outbreak(November 2014) of a mass migration of the polydesmid Chamberlinius hualienensis Wang 1956 on the Japanese Izu Island of Hachijojima 300 km to the south of Tokyo gave this author an opportunity to review the existing literature on millipede mass migrations and to carry out additional observations on the phenomenon in the field as well as the laboratory. Hitherto unreported heavy infestations with phoretic deutonymphs of the mite Histiostoma sp. as well as dense populations of internal rhabditid nematodes(Oscheius cf. necromena and an unidentified species of the genus Fictor), suggest that infestations of this kind could be necromenic and either have been a contributing factor for the mass migration or been a consequence of so manyindividuals occurring together at close proximity. It is concluded that mass migrations and aggregations in millipedes do not have one common cause, but represent phenomena that often are seasonally recurring events and appear identical in their outcome, but which have evolved as responses to different causes in different millipede taxa and therefore need to be examined on a case-to-case basis.展开更多
IT infrastructures have been widely deployed in datacentres by cloud service providers for Infrastructure as a Service (IaaS) with Virtual Machines (VMs). With the rapid development of cloud-based tools and techniques...IT infrastructures have been widely deployed in datacentres by cloud service providers for Infrastructure as a Service (IaaS) with Virtual Machines (VMs). With the rapid development of cloud-based tools and techniques, IaaS is changing the current cloud infrastructure to meet the customer demand. In this paper, an efficient management model is presented and evaluated using our unique Trans-Atlantic high-speed optical fibre network connecting three datacentres located in Coleraine (Northern Ireland), Dublin (Ireland) and Halifax (Canada). Our work highlights the design and implementation of a management system that can dynamically create VMs upon request, process live migration and other services over the high-speed inter-networking Datacentres (DCs). The goal is to provide an efficient and intelligent on-demand management system for virtualization that can make decisions about the migration of VMs and get better utilisation of the network.展开更多
Mobile agents are able to migrate among machines to achieve their tasks. This feature is attractive to design, implement, and maintain distributed systems because we can implement both client-side and server-side prog...Mobile agents are able to migrate among machines to achieve their tasks. This feature is attractive to design, implement, and maintain distributed systems because we can implement both client-side and server-side programming in one mobile agent. However, it involves the increase of data traffic for mobile agent migrations. In this paper, we propose program code caching to reduce the data traffic caused by mobile agent migrations. A mobile agent consists of many program codes that define a task executed in each machine they migrate; thus, the mobile agent migration involves the transfer of their program codes. Therefore, our method reduces the number of the transfer of program codes by using program code cache. We have implemented our method on a mobile agent framework called Maglog and conducted experiments on a meeting scheduling system.展开更多
Photocatalyzed alkylsulfonylation of unactivated alkenes using DABCO.(SO_(2))_(2) and thianthrenium salts via a distal heteroaryl migration process has been developed,which provides a new means of synthesizing a varie...Photocatalyzed alkylsulfonylation of unactivated alkenes using DABCO.(SO_(2))_(2) and thianthrenium salts via a distal heteroaryl migration process has been developed,which provides a new means of synthesizing a variety of valuable alkylsulfonyl-substituted compounds.These alkylsulfonyl radicals couple with unactivated alkenes to undergo efficient intermolecular reactions,followed by distal heteroaryl migration.This mild catalytic method is tolerant of functional groups and affords medicinally relevant alkylsulfonylated heterocycles.展开更多
Internal migration motivated by access to higher education is a relatively unexplored topic in Colombia,leading to a lack of data on its dimensions,characteristics,and impacts on urban space and the emotional conditio...Internal migration motivated by access to higher education is a relatively unexplored topic in Colombia,leading to a lack of data on its dimensions,characteristics,and impacts on urban space and the emotional conditions of migrants.For this reason,an academic program of architecture in a public university was selected to comprehend the internal migrations of students,exploring their territorial experiences,living conditions,and social mobility capacity.An exploratory methodology was designed to recognize the phenomenon through a descriptive analysis,utilizing institutional data,surveys,and interviews.The research identifies the primary reasons,barriers,and impacts experienced by the migrant population in Ibagué,Colombia.The study concludes with recommendations pertaining to both institutional and urban planning to address these identified challenges.展开更多
Rechargeable magnesium batteries(RMBs)have been considered a promising“post lithium-ion battery”system to meet the rapidly increasing demand of the emerging electric vehicle and grid energy storage market.However,th...Rechargeable magnesium batteries(RMBs)have been considered a promising“post lithium-ion battery”system to meet the rapidly increasing demand of the emerging electric vehicle and grid energy storage market.However,the sluggish diffusion kinetics of bivalent Mg^(2+)in the host material,related to the strong Coulomb effect between Mg^(2+)and host anion lattices,hinders their further development toward practical applications.Defect engineering,regarded as an effective strategy to break through the slow migration puzzle,has been validated in various cathode materials for RMBs.In this review,we first thoroughly understand the intrinsic mechanism of Mg^(2+)diffusion in cathode materials,from which the key factors affecting ion diffusion are further presented.Then,the positive effects of purposely introduced defects,including vacancy and doping,and the corresponding strategies for introducing various defects are discussed.The applications of defect engineering in cathode materials for RMBs with advanced electrochemical properties are also summarized.Finally,the existing challenges and future perspectives of defect engineering in cathode materials for the overall high-performance RMBs are described.展开更多
The synthesis of carbon supporter/nanoscale high-entropy alloys(HEAs)electromagnetic response composites by carbothermal shock method has been identified as an advanced strategy for the collaborative competition engin...The synthesis of carbon supporter/nanoscale high-entropy alloys(HEAs)electromagnetic response composites by carbothermal shock method has been identified as an advanced strategy for the collaborative competition engineering of conductive/dielectric genes.Electron migration modes within HEAs as manipulated by the electronegativity,valence electron configurations and molar proportions of constituent elements determine the steady state and efficiency of equivalent dipoles.Herein,enlightened by skin-like effect,a reformative carbothermal shock method using carbonized cellulose paper(CCP)as carbon supporter is used to preserve the oxygencontaining functional groups(O·)of carbonized cellulose fibers(CCF).Nucleation of HEAs and construction of emblematic shell-core CCF/HEAs heterointerfaces are inextricably linked to carbon metabolism induced by O·.Meanwhile,the electron migration mode of switchable electronrich sites promotes the orientation polarization of anisotropic equivalent dipoles.By virtue of the reinforcement strategy,CCP/HEAs composite prepared by 35%molar ratio of Mn element(CCP/HEAs-Mn_(2.15))achieves efficient electromagnetic wave(EMW)absorption of−51.35 dB at an ultra-thin thickness of 1.03 mm.The mechanisms of the resulting dielectric properties of HEAs-based EMW absorbing materials are elucidated by combining theoretical calculations with experimental characterizations,which provide theoretical bases and feasible strategies for the simulation and practical application of electromagnetic functional devices(e.g.,ultra-wideband bandpass filter).展开更多
Schwann cell transplantation is considered one of the most promising cell-based therapy to repair injured spinal cord due to its unique growth-promoting and myelin-forming properties.A the Food and Drug Administration...Schwann cell transplantation is considered one of the most promising cell-based therapy to repair injured spinal cord due to its unique growth-promoting and myelin-forming properties.A the Food and Drug Administration-approved Phase I clinical trial has been conducted to evaluate the safety of transplanted human autologous Schwann cells to treat patients with spinal cord injury.A major challenge for Schwann cell transplantation is that grafted Schwann cells are confined within the lesion cavity,and they do not migrate into the host environment due to the inhibitory barrier formed by injury-induced glial scar,thus limiting axonal reentry into the host spinal cord.Here we introduce a combinatorial strategy by suppressing the inhibitory extracellular environment with injection of lentivirus-mediated transfection of chondroitinase ABC gene at the rostral and caudal borders of the lesion site and simultaneously leveraging the repair capacity of transplanted Schwann cells in adult rats following a mid-thoracic contusive spinal cord injury.We report that when the glial scar was degraded by chondroitinase ABC at the rostral and caudal lesion borders,Schwann cells migrated for considerable distances in both rostral and caudal directions.Such Schwann cell migration led to enhanced axonal regrowth,including the serotonergic and dopaminergic axons originating from supraspinal regions,and promoted recovery of locomotor and urinary bladder functions.Importantly,the Schwann cell survival and axonal regrowth persisted up to 6 months after the injury,even when treatment was delayed for 3 months to mimic chronic spinal cord injury.These findings collectively show promising evidence for a combinatorial strategy with chondroitinase ABC and Schwann cells in promoting remodeling and recovery of function following spinal cord injury.展开更多
BACKGROUND The objective of the current study was to elucidate the clinical mechanism through which phospholipase D2(PLD2)exerted a regulatory effect on neutrophil migra-tion,thereby alleviating the progression of acu...BACKGROUND The objective of the current study was to elucidate the clinical mechanism through which phospholipase D2(PLD2)exerted a regulatory effect on neutrophil migra-tion,thereby alleviating the progression of acute pancreatitis.AIM To elucidate the clinical mechanism through which PLD2 exerted a regulatory effect on neutrophil migration,thereby alleviating the progression of acute pan-creatitis.METHODS The study involved 90 patients diagnosed with acute pancreatitis,admitted to our hospital between March 2020 and November 2022.A retrospective analysis was conducted,categorizing patients based on Ranson score severity into mild(n=25),moderate(n=30),and severe(n=35)groups.Relevant data was collected for each group.Western blot analysis assessed PLD2 protein expression in patient serum.Real-time reverse transcription polymerase chain reaction was used to evaluate the mRNA expression of chemokine receptors associated with neutrophil migration.Serum levels of inflammatory factors in patients were detected using enzyme-linked immunosorbent assay.Transwell migration tests were conducted to compare migration of neutrophils across groups and analyze the influence of PLD2 on neutrophil migration.RESULTS Overall data analysis did not find significant differences between patient groups(P>0.05).The expression of PLD2 protein in the severe group was lower than that in the moderate and mild groups(P<0.05).The expression level of PLD2 in the moderate group was also lower than that in the mild group(P<0.05).The severity of acute pancreatitis is negatively correlated with PLD2 expression(r=-0.75,P=0.002).The mRNA levels of C-X-C chemokine receptor type 1,C-X-C chemokine receptor type 2,C-C chemokine receptor type 2,and C-C chemokine receptor type 5 in the severe group are significantly higher than those in the moderate and mild groups(P<0.05),and the expression levels in the moderate group are also higher than those in the mild group(P<0.05).The levels of C-reactive protein,tumor necrosis factor-α,interleukin-1β,and interleukin-6 in the severe group were higher than those in the moderate and mild groups(P<0.05),and the levels in the moderate group were also higher than those in the mild group(P<0.05).The number of migrating neutrophils in the severe group was higher than that in the moderate and mild groups(P<0.05),and the moderate group was also higher than the mild group(P<0.05).In addition,the number of migrating neutrophils in the mild group combined with PLD2 inhibitor was higher than that in the mild group(P<0.05),and the number of migrating neutrophils in the moderate group combined with PLD2 inhibitor was higher than that in the moderate group(P<0.05).The number of migrating neutrophils in the severe group+PLD2 inhibitor group was significantly higher than that in the severe group(P<0.05),indicating that PLD2 inhibitors significantly stimulated neutrophil migration.CONCLUSION PLD2 exerted a crucial regulatory role in the pathological progression of acute pancreatitis.Its protein expression varied among patients based on the severity of the disease,and a negative correlation existed between PLD2 expression and disease severity.Additionally,PLD2 appeared to impede acute pancreatitis progression by limiting neutrophil migration.展开更多
Memristive crossbar arrays(MCAs)offer parallel data storage and processing for energy-efficient neuromorphic computing.However,most wafer-scale MCAs that are compatible with complementary metal-oxide-semiconductor(CMO...Memristive crossbar arrays(MCAs)offer parallel data storage and processing for energy-efficient neuromorphic computing.However,most wafer-scale MCAs that are compatible with complementary metal-oxide-semiconductor(CMOS)technology still suffer from substantially larger energy consumption than biological synapses,due to the slow kinetics of forming conductive paths inside the memristive units.Here we report wafer-scale Ag_(2)S-based MCAs realized using CMOS-compatible processes at temperatures below 160℃.Ag_(2)S electrolytes supply highly mobile Ag+ions,and provide the Ag/Ag_(2)S interface with low silver nucleation barrier to form silver filaments at low energy costs.By further enhancing Ag+migration in Ag_(2)S electrolytes via microstructure modulation,the integrated memristors exhibit a record low threshold of approximately−0.1 V,and demonstrate ultra-low switching-energies reaching femtojoule values as observed in biological synapses.The low-temperature process also enables MCA integration on polyimide substrates for applications in flexible electronics.Moreover,the intrinsic nonidealities of the memristive units for deep learning can be compensated by employing an advanced training algorithm.An impressive accuracy of 92.6%in image recognition simulations is demonstrated with the MCAs after the compensation.The demonstrated MCAs provide a promising device option for neuromorphic computing with ultra-high energy-efficiency.展开更多
Microglia,the primary immune cells within the brain,have gained recognition as a promising therapeutic target for managing neurodegenerative diseases within the central nervous system,including Parkinson’s disease.Na...Microglia,the primary immune cells within the brain,have gained recognition as a promising therapeutic target for managing neurodegenerative diseases within the central nervous system,including Parkinson’s disease.Nanoscale perfluorocarbon droplets have been reported to not only possess a high oxygen-carrying capacity,but also exhibit remarkable anti-inflammatory properties.However,the role of perfluoropentane in microglia-mediated central inflammatory reactions remains poorly understood.In this study,we developed perfluoropentane-based oxygen-loaded nanodroplets(PFP-OLNDs)and found that pretreatment with these droplets suppressed the lipopolysaccharide-induced activation of M1-type microglia in vitro and in vivo,and suppressed microglial activation in a mouse model of Parkinson’s disease.Microglial suppression led to a reduction in the inflammatory response,oxidative stress,and cell migration capacity in vitro.Consequently,the neurotoxic effects were mitigated,which alleviated neuronal degeneration.Additionally,ultrahigh-performance liquid chromatography–tandem mass spectrometry showed that the anti-inflammatory effects of PFP-OLNDs mainly resulted from the modulation of microglial metabolic reprogramming.We further showed that PFP-OLNDs regulated microglial metabolic reprogramming through the AKT-mTOR-HIF-1αpathway.Collectively,our findings suggest that the novel PFP-OLNDs constructed in this study alleviate microglia-mediated central inflammatory reactions through metabolic reprogramming.展开更多
The presence of endogenous neural stem/progenitor cells in the adult mammalian brain suggests that the central nervous system can be repaired and regenerated after injury.However,whether it is possible to stimulate ne...The presence of endogenous neural stem/progenitor cells in the adult mammalian brain suggests that the central nervous system can be repaired and regenerated after injury.However,whether it is possible to stimulate neurogenesis and reconstruct cortical layers II to VI in non-neurogenic regions,such as the cortex,remains unknown.In this study,we implanted a hyaluronic acid collagen gel loaded with basic fibroblast growth factor into the motor cortex immediately following traumatic injury.Our findings reveal that this gel effectively stimulated the proliferation and migration of endogenous neural stem/progenitor cells,as well as their differentiation into mature and functionally integrated neurons.Importantly,these new neurons reconstructed the architecture of cortical layers II to VI,integrated into the existing neural circuitry,and ultimately led to improved brain function.These findings offer novel insight into potential clinical treatments for traumatic cerebral cortex injuries.展开更多
A single-species population model with migrations and harvest between the protected patch and the unprotected patch is formulated and investigated in this paper. We study the local stability and the global stability o...A single-species population model with migrations and harvest between the protected patch and the unprotected patch is formulated and investigated in this paper. We study the local stability and the global stability of the equilibria. The research points out, under some suitable conditions, the singlespecies population model admits a unique positive equilibrium, which is globally asymptotically stable. We also derive that the trivial solution is globally asymptotically stable when the harvesting rate exceeds the threshold. Further, we discuss the practical effects of the protection zones and the harvest. The main results indicate that the protective zones indeed eliminate the extinction of the species under some cases, and the theoretical threshold of harvest to the practical management of the endangered species is provided as well. To end this contribution and to check the validity of the main results, numerical simulations are separately carried out to illustrate these results.展开更多
Over one hundred artifacts, including shards, chopped wood, bronze and iron ware debris as well as footprints, have been discovered during archaeological investigations at and around the central Taklamakan Desert Yuan...Over one hundred artifacts, including shards, chopped wood, bronze and iron ware debris as well as footprints, have been discovered during archaeological investigations at and around the central Taklamakan Desert Yuansha Site (38°52′N, 81°35′E). Dating (14C and OSL) and landform study show that the present-day dry Keriya River once sustained an oasis human settle- ment in 2.6 ka BP, historically falling into the Spring and Autumn Period (716-475 BCE) of Chinese history. The chronology and archaeological interpretations also show that some 400 years later, the local Keriya River channel had shifted 40 km southeast to sustain a Western Han (206 BCE-25 CE) Wumi settlement at the Karadun site. In the meantime, river-channel migration had allowed reoccupation of a site west of Yuansha City around 1.9 ka BP (abandoned again by 1.6 ka BP). The remains' chronology shows that this site was affiliated to Wumi culture and Eastern Han (24-220 CE) dynasty rule. Palaeoclimatic records indicate that the migrations of the river and oasis settlers between 2.7 and 1.6 ka BP were coeval with Central Asian climate changes. Yuansha City was built just after the end of 2.8 ka BP glacier advances in western China, suggesting that release of more water during the subsequent glacier recession may have facilitated oasis development such that Iron Age European peoples could settle in the Tarim Basin. As shown from analysis of archeological remains, not only at Yuansha but also in other ancient cities in the Tarim such as Loulan and Jingjue (Niya), conditions around 1.6 ka BP were dry enough to cause oasis decline. Thus, the results reported here enhance our knowledge about environmental changes and their effects on human activities and cultural evolution in western China and will stimulate further interdisciplinary studies of landscape and oasis history in the Tarim Basin.展开更多
Over the last three decades, special purpose “entomological” radars have contributed much to the development of our understanding of insect migration, especially of the nocturnal migrations at altitudes of up to ~1...Over the last three decades, special purpose “entomological” radars have contributed much to the development of our understanding of insect migration, especially of the nocturnal migrations at altitudes of up to ~1 km that are regularly undertaken by many important pest species. One of the limitations of early radar studies, the difficulty of maintaining observations over long periods, has recently been overcome by the development of automated units that operate autonomously and transmit summaries of their observations to a base laboratory over the public telephone network. These relatively low cost Insect Monitoring Radars (IMRs) employ a novel “ZLC” configuration that allows high quality data on the migrants' flight parameters and identity to be acquired. Two IMRs are currently operating in the semi arid inland of eastern Australia, in a region where populations of migrant moths (Lepidoptera) and Australian plague locusts Chortoicetes terminifera (Orthoptera) commonly originate, and some examples of outputs from one of these units are presented. IMRs are able to provide the data needed to characterize a migration system, i.e. to estimate the probabilities of migration events occurring in particular directions at particular seasons and in response to particular environmental conditions and cues. They also appear capable of fulfilling a “sentinel” role for pest management organisations, alerting forecasters to major migration events and thus to the likely new locations of potential target populations. Finally, they may be suitable for a more general ecological monitoring role, perhaps especially for quantifying year to year variations in biological productivity.展开更多
The development of azide migration reactions is a formidable challenge due to potential competition from side processes driven by the release of molecular nitrogen. Here, we show a novel neighbouring carbonyl group-as...The development of azide migration reactions is a formidable challenge due to potential competition from side processes driven by the release of molecular nitrogen. Here, we show a novel neighbouring carbonyl group-assisted sequential 1,2-azide and 1,4-oxygen migration reaction of α-vinyl azides for the efficient preparation of a range of α-azido ketones. This represents the first transformation of α-vinyl azides into α-azido ketones. Notable features of this method are its high efficiency, broad substrate scope, excellent functional group compatibility, and high yields. The computational studies gave a key insights into the regioselective 1,2-azide and 1,4-oxygen migrations assisted by the neighbouring carbonyl group. Further conversions into a variety of nitrogen-containing compounds demonstrated the synthetic utility of the α-azido ketone products. Preliminary mechanistic studies disclosed a novel reaction mechanism involving neighbouring carbonyl group-assisted sequential 1,2-azide and1,4-oxygen migrations.展开更多
The earliest written record of the term “Kaxabu” dates to the 1908 survey report by the Japanese scholar Ino Kanori. In his study of the Pazzehe tribe in central Taiwan, he wrote: “Kaxabu was the name given by the...The earliest written record of the term “Kaxabu” dates to the 1908 survey report by the Japanese scholar Ino Kanori. In his study of the Pazzehe tribe in central Taiwan, he wrote: “Kaxabu was the name given by the Pazzehe to Daiyao'puru, a small division of its ethnic group.” During the Qing era, the Pazzehe was called the Anli group by Chinese speakers in Taiwan, while the Kaxabu were named Puzili she (the Puzili tribe). Since the Kaxabu originated from the Pazzehe, thus in determining the time when the Kaxabu became distinct from the Pazzehe and in exploring the differences between them, we will also elucidate historical developments before the Japanese colonial era. Using Qing historical materials such as travelogues, expedition-records, newspapers, data from fieldwork, surveys, and interviews, this study traces the intervention of the Qing court into tribal relationships in central Taiwan, beginning with the Dajiaxi she Incident (1731-32), it touches on the changing environment of the Kaxabu/ Puzili she in their migrations in order to shed light on the development of the two distinctive identities-the Kaxabu and Pazzehe/Anli group. The analysis also reveals the impact of uprisings and migrations upon the border area surrounding Qing Taiwan, as well as problems of ethnic identification and geography.展开更多
文摘During the 1950s the Hula wetlands and old lake were drained and the land converted utilization to agriculture and ecotourism. As a result of the drainage, the Peat Soil was exposed to atmospheric oxygen. The geochemical environment was modified from reductive to oxidative and the Nitrogen in it was converted from Ammonium to Nitrate. Intensive migration of Nitrate from the Hula Valley induced a national concern of water quality deterioration in the lake which was dissipated when Nitrogen deficiency was developed in Lake Kinneret. Forty years after drainage the ecosystem structure was renovated (Hula Project, HP) aimed at agricultural management and nutrient migration reduction. The paper examines through evaluation of the ecological data record (1993-2018) the impact of hydrological changes, attributed to the HP implementation on nutrient dynamics within surface waters in the Hula Valley. It is suggested that soil moisture elevation by irrigation in summer reduced Phosphorus and enhanced Nitrate concentrations.
基金supported by the Opening Fund of Key Laboratory of Continental Shale Accumulation and Development(Northeast Petroleum University,China)the National Natural Science Foundation of China(Grant No.51605089,Grant No.41972156)
文摘The behavior of oil and water in tight rocks can change the distribution of oil or water in pores,which affects the production of crude oil.Nuclear Magnetic Resonance(NMR)method is an effective and nondestructive tool for evaluating rocks with comparison and analysis both quantitatively and qualitatively.In our study,20 MHz NMR Relaxometry is used as a key technique to study the changes of water and oil behaviors in Chinese lacustrine Qingshankou shales under different saturated states(imbibition and evaporation without pressure).The results show that variation in different proton populations(water,oil and organic)can be distinguished using 2D T_(1)-T_(2)maps.The comparison among T_(1)-T_(2)maps with different saturated states shows that different signal regions changed during oil and water migrations,which the 1D NMR Relaxometry may be not easy to approach.Combined with the pyrolysis analysis,T2 shift and differences of signal regions in T_(1)-T_(2)maps can reflect properties such as wettability and composition(organic matter,clay and magnetic minerals)to some extent.This study provides better insight into oil and water behaviors in lacustrine oil shales with further understanding of 20 MHz NMR 2D T_(1)-T_(2)maps both in qualitative and quantitative analysis.
基金supported by a postgraduate fellowship from the Basque Governmentsupported by project CGL2007-61395(Ministry of Education and Science,Government of Spain)
文摘Fuel accumulation, mainly as fatty acids, is one of the main characteristics of migratory, birds. Studying to what extent each population or species manages fuel load and how it varies along routes of migration or between seasons (autumn and spring migrations) is crucial to our understanding of bird migration strategies. Our aim here was to analyse whether migratory blackcaps Sylvia atrieapilla passing through northern Iberia differ in their mean fuel loads, rate of fuel accumulation and ' potential' flight ranges between migration seasons. Blackcaps were mist netted for 4 h-periods beginning at dawn from 16 September to 15 November 2003 - 2005, and from 1 March to 30 April 2004 - 2006 in a European Atlantic hedgerow at Loza, northern Iberia. Both fuel load and fuel deposition rate (this latter assessed with difference in body mass of within-season recaptured individuals) were higher in autumn than in spring. Possible hypotheses explaining these results could be seasonal-associated variations in food availability (likely lower during spring than during autumn), the fact that a fraction of the migrants captured in spring could breed close to the study area and different selective pressures for breeding and wintering
文摘Mass aggregations and migrations of millipedes despite numerous attempts to find causes for their occurrences are still an enigma. They have been reported from both southern and northern hemisphere countries, from highlands and lowlands of both tropical and temperate regions and they can involve species belonging to the orders Julida and Spirobolida, Polydesmida and Glomerida. According to the main suggestions put forward in the past, mass occurrences in Diplopoda occur:(1) because of a lack of food and a population increase beyond sustainable levels;(2) for the purpose of reproduction and in order to locate suitable oviposition sites;(3) to find overwintering or aestivation sites;(4) because of habitat disruption and changes in the local environment;(5) as a consequence of weather conditions the year(or winter and spring) before. A recent outbreak(November 2014) of a mass migration of the polydesmid Chamberlinius hualienensis Wang 1956 on the Japanese Izu Island of Hachijojima 300 km to the south of Tokyo gave this author an opportunity to review the existing literature on millipede mass migrations and to carry out additional observations on the phenomenon in the field as well as the laboratory. Hitherto unreported heavy infestations with phoretic deutonymphs of the mite Histiostoma sp. as well as dense populations of internal rhabditid nematodes(Oscheius cf. necromena and an unidentified species of the genus Fictor), suggest that infestations of this kind could be necromenic and either have been a contributing factor for the mass migration or been a consequence of so manyindividuals occurring together at close proximity. It is concluded that mass migrations and aggregations in millipedes do not have one common cause, but represent phenomena that often are seasonally recurring events and appear identical in their outcome, but which have evolved as responses to different causes in different millipede taxa and therefore need to be examined on a case-to-case basis.
文摘IT infrastructures have been widely deployed in datacentres by cloud service providers for Infrastructure as a Service (IaaS) with Virtual Machines (VMs). With the rapid development of cloud-based tools and techniques, IaaS is changing the current cloud infrastructure to meet the customer demand. In this paper, an efficient management model is presented and evaluated using our unique Trans-Atlantic high-speed optical fibre network connecting three datacentres located in Coleraine (Northern Ireland), Dublin (Ireland) and Halifax (Canada). Our work highlights the design and implementation of a management system that can dynamically create VMs upon request, process live migration and other services over the high-speed inter-networking Datacentres (DCs). The goal is to provide an efficient and intelligent on-demand management system for virtualization that can make decisions about the migration of VMs and get better utilisation of the network.
文摘Mobile agents are able to migrate among machines to achieve their tasks. This feature is attractive to design, implement, and maintain distributed systems because we can implement both client-side and server-side programming in one mobile agent. However, it involves the increase of data traffic for mobile agent migrations. In this paper, we propose program code caching to reduce the data traffic caused by mobile agent migrations. A mobile agent consists of many program codes that define a task executed in each machine they migrate; thus, the mobile agent migration involves the transfer of their program codes. Therefore, our method reduces the number of the transfer of program codes by using program code cache. We have implemented our method on a mobile agent framework called Maglog and conducted experiments on a meeting scheduling system.
基金the National Natural Science Foundation of China(Nos.21702103 and 21522604)the Jiangsu Synergetic Innovation Center for Advanced Bio-Manufacture(No.XTD2203)+1 种基金the Natural Science Research Projects of Jiangsu Higher Education(No.19KJB150027)Jiangsu Funding Program for Excellent Postdoctoral Talent(No.2022ZB389).
文摘Photocatalyzed alkylsulfonylation of unactivated alkenes using DABCO.(SO_(2))_(2) and thianthrenium salts via a distal heteroaryl migration process has been developed,which provides a new means of synthesizing a variety of valuable alkylsulfonyl-substituted compounds.These alkylsulfonyl radicals couple with unactivated alkenes to undergo efficient intermolecular reactions,followed by distal heteroaryl migration.This mild catalytic method is tolerant of functional groups and affords medicinally relevant alkylsulfonylated heterocycles.
文摘Internal migration motivated by access to higher education is a relatively unexplored topic in Colombia,leading to a lack of data on its dimensions,characteristics,and impacts on urban space and the emotional conditions of migrants.For this reason,an academic program of architecture in a public university was selected to comprehend the internal migrations of students,exploring their territorial experiences,living conditions,and social mobility capacity.An exploratory methodology was designed to recognize the phenomenon through a descriptive analysis,utilizing institutional data,surveys,and interviews.The research identifies the primary reasons,barriers,and impacts experienced by the migrant population in Ibagué,Colombia.The study concludes with recommendations pertaining to both institutional and urban planning to address these identified challenges.
基金support of the National Natural Science Foundation of China(Grant No.22225801,22178217 and 22308216)supported by the Fundamental Research Funds for the Central Universities,conducted at Tongji University.
文摘Rechargeable magnesium batteries(RMBs)have been considered a promising“post lithium-ion battery”system to meet the rapidly increasing demand of the emerging electric vehicle and grid energy storage market.However,the sluggish diffusion kinetics of bivalent Mg^(2+)in the host material,related to the strong Coulomb effect between Mg^(2+)and host anion lattices,hinders their further development toward practical applications.Defect engineering,regarded as an effective strategy to break through the slow migration puzzle,has been validated in various cathode materials for RMBs.In this review,we first thoroughly understand the intrinsic mechanism of Mg^(2+)diffusion in cathode materials,from which the key factors affecting ion diffusion are further presented.Then,the positive effects of purposely introduced defects,including vacancy and doping,and the corresponding strategies for introducing various defects are discussed.The applications of defect engineering in cathode materials for RMBs with advanced electrochemical properties are also summarized.Finally,the existing challenges and future perspectives of defect engineering in cathode materials for the overall high-performance RMBs are described.
基金Financial support from the National Natural Science Foundation of China(52372289,52102368,52231007,12327804,T2321003,22088101,22178037 and U22A20424)Regional Joint Fund for Basic Research and Applied Basic Research of Guangdong Province(No.2020A1515110905)+1 种基金Guangdong Special Fund for key Areas(20237DZX3042)Shenzhen Stable Support Project,Liaoning Revitalization Talents Program(XLYC2002114)are highly appreciated.
文摘The synthesis of carbon supporter/nanoscale high-entropy alloys(HEAs)electromagnetic response composites by carbothermal shock method has been identified as an advanced strategy for the collaborative competition engineering of conductive/dielectric genes.Electron migration modes within HEAs as manipulated by the electronegativity,valence electron configurations and molar proportions of constituent elements determine the steady state and efficiency of equivalent dipoles.Herein,enlightened by skin-like effect,a reformative carbothermal shock method using carbonized cellulose paper(CCP)as carbon supporter is used to preserve the oxygencontaining functional groups(O·)of carbonized cellulose fibers(CCF).Nucleation of HEAs and construction of emblematic shell-core CCF/HEAs heterointerfaces are inextricably linked to carbon metabolism induced by O·.Meanwhile,the electron migration mode of switchable electronrich sites promotes the orientation polarization of anisotropic equivalent dipoles.By virtue of the reinforcement strategy,CCP/HEAs composite prepared by 35%molar ratio of Mn element(CCP/HEAs-Mn_(2.15))achieves efficient electromagnetic wave(EMW)absorption of−51.35 dB at an ultra-thin thickness of 1.03 mm.The mechanisms of the resulting dielectric properties of HEAs-based EMW absorbing materials are elucidated by combining theoretical calculations with experimental characterizations,which provide theoretical bases and feasible strategies for the simulation and practical application of electromagnetic functional devices(e.g.,ultra-wideband bandpass filter).
基金supported in part by NIH R01 NS100531,R01 NS103481NIH R21NS130241(to LD)+3 种基金Merit Review Award I01 BX002356,I01 BX003705 from the U.S.Department of Veterans AffairsIndiana Spinal Cord and Brain Injury Research Foundation(No.19919)Mari Hulman George Endowment Funds(to XMX)Indiana Spinal Cord&Brain Injury Research Fund from ISDH(to NKL and LD)。
文摘Schwann cell transplantation is considered one of the most promising cell-based therapy to repair injured spinal cord due to its unique growth-promoting and myelin-forming properties.A the Food and Drug Administration-approved Phase I clinical trial has been conducted to evaluate the safety of transplanted human autologous Schwann cells to treat patients with spinal cord injury.A major challenge for Schwann cell transplantation is that grafted Schwann cells are confined within the lesion cavity,and they do not migrate into the host environment due to the inhibitory barrier formed by injury-induced glial scar,thus limiting axonal reentry into the host spinal cord.Here we introduce a combinatorial strategy by suppressing the inhibitory extracellular environment with injection of lentivirus-mediated transfection of chondroitinase ABC gene at the rostral and caudal borders of the lesion site and simultaneously leveraging the repair capacity of transplanted Schwann cells in adult rats following a mid-thoracic contusive spinal cord injury.We report that when the glial scar was degraded by chondroitinase ABC at the rostral and caudal lesion borders,Schwann cells migrated for considerable distances in both rostral and caudal directions.Such Schwann cell migration led to enhanced axonal regrowth,including the serotonergic and dopaminergic axons originating from supraspinal regions,and promoted recovery of locomotor and urinary bladder functions.Importantly,the Schwann cell survival and axonal regrowth persisted up to 6 months after the injury,even when treatment was delayed for 3 months to mimic chronic spinal cord injury.These findings collectively show promising evidence for a combinatorial strategy with chondroitinase ABC and Schwann cells in promoting remodeling and recovery of function following spinal cord injury.
文摘BACKGROUND The objective of the current study was to elucidate the clinical mechanism through which phospholipase D2(PLD2)exerted a regulatory effect on neutrophil migra-tion,thereby alleviating the progression of acute pancreatitis.AIM To elucidate the clinical mechanism through which PLD2 exerted a regulatory effect on neutrophil migration,thereby alleviating the progression of acute pan-creatitis.METHODS The study involved 90 patients diagnosed with acute pancreatitis,admitted to our hospital between March 2020 and November 2022.A retrospective analysis was conducted,categorizing patients based on Ranson score severity into mild(n=25),moderate(n=30),and severe(n=35)groups.Relevant data was collected for each group.Western blot analysis assessed PLD2 protein expression in patient serum.Real-time reverse transcription polymerase chain reaction was used to evaluate the mRNA expression of chemokine receptors associated with neutrophil migration.Serum levels of inflammatory factors in patients were detected using enzyme-linked immunosorbent assay.Transwell migration tests were conducted to compare migration of neutrophils across groups and analyze the influence of PLD2 on neutrophil migration.RESULTS Overall data analysis did not find significant differences between patient groups(P>0.05).The expression of PLD2 protein in the severe group was lower than that in the moderate and mild groups(P<0.05).The expression level of PLD2 in the moderate group was also lower than that in the mild group(P<0.05).The severity of acute pancreatitis is negatively correlated with PLD2 expression(r=-0.75,P=0.002).The mRNA levels of C-X-C chemokine receptor type 1,C-X-C chemokine receptor type 2,C-C chemokine receptor type 2,and C-C chemokine receptor type 5 in the severe group are significantly higher than those in the moderate and mild groups(P<0.05),and the expression levels in the moderate group are also higher than those in the mild group(P<0.05).The levels of C-reactive protein,tumor necrosis factor-α,interleukin-1β,and interleukin-6 in the severe group were higher than those in the moderate and mild groups(P<0.05),and the levels in the moderate group were also higher than those in the mild group(P<0.05).The number of migrating neutrophils in the severe group was higher than that in the moderate and mild groups(P<0.05),and the moderate group was also higher than the mild group(P<0.05).In addition,the number of migrating neutrophils in the mild group combined with PLD2 inhibitor was higher than that in the mild group(P<0.05),and the number of migrating neutrophils in the moderate group combined with PLD2 inhibitor was higher than that in the moderate group(P<0.05).The number of migrating neutrophils in the severe group+PLD2 inhibitor group was significantly higher than that in the severe group(P<0.05),indicating that PLD2 inhibitors significantly stimulated neutrophil migration.CONCLUSION PLD2 exerted a crucial regulatory role in the pathological progression of acute pancreatitis.Its protein expression varied among patients based on the severity of the disease,and a negative correlation existed between PLD2 expression and disease severity.Additionally,PLD2 appeared to impede acute pancreatitis progression by limiting neutrophil migration.
基金supported by the Swedish Strategic Research Foundation(SSF FFL15-0174 to Zhen Zhang)the Swedish Research Council(VR 2018-06030 and 2019-04690 to Zhen Zhang)+1 种基金the Wallenberg Academy Fellow Extension Program(KAW 2020-0190 to Zhen Zhang)the Olle Engkvist Foundation(Postdoc grant 214-0322 to Zhen Zhang).
文摘Memristive crossbar arrays(MCAs)offer parallel data storage and processing for energy-efficient neuromorphic computing.However,most wafer-scale MCAs that are compatible with complementary metal-oxide-semiconductor(CMOS)technology still suffer from substantially larger energy consumption than biological synapses,due to the slow kinetics of forming conductive paths inside the memristive units.Here we report wafer-scale Ag_(2)S-based MCAs realized using CMOS-compatible processes at temperatures below 160℃.Ag_(2)S electrolytes supply highly mobile Ag+ions,and provide the Ag/Ag_(2)S interface with low silver nucleation barrier to form silver filaments at low energy costs.By further enhancing Ag+migration in Ag_(2)S electrolytes via microstructure modulation,the integrated memristors exhibit a record low threshold of approximately−0.1 V,and demonstrate ultra-low switching-energies reaching femtojoule values as observed in biological synapses.The low-temperature process also enables MCA integration on polyimide substrates for applications in flexible electronics.Moreover,the intrinsic nonidealities of the memristive units for deep learning can be compensated by employing an advanced training algorithm.An impressive accuracy of 92.6%in image recognition simulations is demonstrated with the MCAs after the compensation.The demonstrated MCAs provide a promising device option for neuromorphic computing with ultra-high energy-efficiency.
基金supported by the National Natural Science Foundation of China,No.82101327(to YY)President Foundation of Nanfang Hospital,Southern Medical University,No.2020A001(to WL)+1 种基金Guangdong Basic and Applied Basic Research Foundation,Nos.2019A1515110150,2022A1515012362(both to YY)Guangzhou Science and Technology Project,No.202201020111(to YY).
文摘Microglia,the primary immune cells within the brain,have gained recognition as a promising therapeutic target for managing neurodegenerative diseases within the central nervous system,including Parkinson’s disease.Nanoscale perfluorocarbon droplets have been reported to not only possess a high oxygen-carrying capacity,but also exhibit remarkable anti-inflammatory properties.However,the role of perfluoropentane in microglia-mediated central inflammatory reactions remains poorly understood.In this study,we developed perfluoropentane-based oxygen-loaded nanodroplets(PFP-OLNDs)and found that pretreatment with these droplets suppressed the lipopolysaccharide-induced activation of M1-type microglia in vitro and in vivo,and suppressed microglial activation in a mouse model of Parkinson’s disease.Microglial suppression led to a reduction in the inflammatory response,oxidative stress,and cell migration capacity in vitro.Consequently,the neurotoxic effects were mitigated,which alleviated neuronal degeneration.Additionally,ultrahigh-performance liquid chromatography–tandem mass spectrometry showed that the anti-inflammatory effects of PFP-OLNDs mainly resulted from the modulation of microglial metabolic reprogramming.We further showed that PFP-OLNDs regulated microglial metabolic reprogramming through the AKT-mTOR-HIF-1αpathway.Collectively,our findings suggest that the novel PFP-OLNDs constructed in this study alleviate microglia-mediated central inflammatory reactions through metabolic reprogramming.
基金supported by the National Natural Science Foundation of China,Nos.82272171(to ZY),82271403(to XL),81941011(to XL),31971279(to ZY),31730030(to XL)the Natural Science Foundation of Beijing,No.7222004(to HD).
文摘The presence of endogenous neural stem/progenitor cells in the adult mammalian brain suggests that the central nervous system can be repaired and regenerated after injury.However,whether it is possible to stimulate neurogenesis and reconstruct cortical layers II to VI in non-neurogenic regions,such as the cortex,remains unknown.In this study,we implanted a hyaluronic acid collagen gel loaded with basic fibroblast growth factor into the motor cortex immediately following traumatic injury.Our findings reveal that this gel effectively stimulated the proliferation and migration of endogenous neural stem/progenitor cells,as well as their differentiation into mature and functionally integrated neurons.Importantly,these new neurons reconstructed the architecture of cortical layers II to VI,integrated into the existing neural circuitry,and ultimately led to improved brain function.These findings offer novel insight into potential clinical treatments for traumatic cerebral cortex injuries.
基金supported by the National Natural Science Foundation of China(Grant Nos.11201075,11601085 and 61773122)Natural Science Foundation of Fujian Province(Grant No.2016J01015)
文摘A single-species population model with migrations and harvest between the protected patch and the unprotected patch is formulated and investigated in this paper. We study the local stability and the global stability of the equilibria. The research points out, under some suitable conditions, the singlespecies population model admits a unique positive equilibrium, which is globally asymptotically stable. We also derive that the trivial solution is globally asymptotically stable when the harvesting rate exceeds the threshold. Further, we discuss the practical effects of the protection zones and the harvest. The main results indicate that the protective zones indeed eliminate the extinction of the species under some cases, and the theoretical threshold of harvest to the practical management of the endangered species is provided as well. To end this contribution and to check the validity of the main results, numerical simulations are separately carried out to illustrate these results.
基金supported by the National Basic Research Program of China (Grant No. 2009CB421308)the National Natural Science Foundation of China (Grant Nos. 40701188 and 40971020)+2 种基金the Natural Science Foundation of Xinjiang Uygur Autonomous Region (Grant No. 2010211A12)the Natural Science Foundation of Xinjiang University (Grant No. BS060112)the Project of Oasis Ecological Key Lab of Education Ministry Xinjiang University (Grant No. XJDX0206-2007-08)
文摘Over one hundred artifacts, including shards, chopped wood, bronze and iron ware debris as well as footprints, have been discovered during archaeological investigations at and around the central Taklamakan Desert Yuansha Site (38°52′N, 81°35′E). Dating (14C and OSL) and landform study show that the present-day dry Keriya River once sustained an oasis human settle- ment in 2.6 ka BP, historically falling into the Spring and Autumn Period (716-475 BCE) of Chinese history. The chronology and archaeological interpretations also show that some 400 years later, the local Keriya River channel had shifted 40 km southeast to sustain a Western Han (206 BCE-25 CE) Wumi settlement at the Karadun site. In the meantime, river-channel migration had allowed reoccupation of a site west of Yuansha City around 1.9 ka BP (abandoned again by 1.6 ka BP). The remains' chronology shows that this site was affiliated to Wumi culture and Eastern Han (24-220 CE) dynasty rule. Palaeoclimatic records indicate that the migrations of the river and oasis settlers between 2.7 and 1.6 ka BP were coeval with Central Asian climate changes. Yuansha City was built just after the end of 2.8 ka BP glacier advances in western China, suggesting that release of more water during the subsequent glacier recession may have facilitated oasis development such that Iron Age European peoples could settle in the Tarim Basin. As shown from analysis of archeological remains, not only at Yuansha but also in other ancient cities in the Tarim such as Loulan and Jingjue (Niya), conditions around 1.6 ka BP were dry enough to cause oasis decline. Thus, the results reported here enhance our knowledge about environmental changes and their effects on human activities and cultural evolution in western China and will stimulate further interdisciplinary studies of landscape and oasis history in the Tarim Basin.
文摘Over the last three decades, special purpose “entomological” radars have contributed much to the development of our understanding of insect migration, especially of the nocturnal migrations at altitudes of up to ~1 km that are regularly undertaken by many important pest species. One of the limitations of early radar studies, the difficulty of maintaining observations over long periods, has recently been overcome by the development of automated units that operate autonomously and transmit summaries of their observations to a base laboratory over the public telephone network. These relatively low cost Insect Monitoring Radars (IMRs) employ a novel “ZLC” configuration that allows high quality data on the migrants' flight parameters and identity to be acquired. Two IMRs are currently operating in the semi arid inland of eastern Australia, in a region where populations of migrant moths (Lepidoptera) and Australian plague locusts Chortoicetes terminifera (Orthoptera) commonly originate, and some examples of outputs from one of these units are presented. IMRs are able to provide the data needed to characterize a migration system, i.e. to estimate the probabilities of migration events occurring in particular directions at particular seasons and in response to particular environmental conditions and cues. They also appear capable of fulfilling a “sentinel” role for pest management organisations, alerting forecasters to major migration events and thus to the likely new locations of potential target populations. Finally, they may be suitable for a more general ecological monitoring role, perhaps especially for quantifying year to year variations in biological productivity.
基金the National Natural Science Foundation of China(21871043)the Department of Science and Technology of Jilin Province(20180101185JC,20190701012GH)the Fundamental Research Funds for the Central Universities(2412019ZD001).
文摘The development of azide migration reactions is a formidable challenge due to potential competition from side processes driven by the release of molecular nitrogen. Here, we show a novel neighbouring carbonyl group-assisted sequential 1,2-azide and 1,4-oxygen migration reaction of α-vinyl azides for the efficient preparation of a range of α-azido ketones. This represents the first transformation of α-vinyl azides into α-azido ketones. Notable features of this method are its high efficiency, broad substrate scope, excellent functional group compatibility, and high yields. The computational studies gave a key insights into the regioselective 1,2-azide and 1,4-oxygen migrations assisted by the neighbouring carbonyl group. Further conversions into a variety of nitrogen-containing compounds demonstrated the synthetic utility of the α-azido ketone products. Preliminary mechanistic studies disclosed a novel reaction mechanism involving neighbouring carbonyl group-assisted sequential 1,2-azide and1,4-oxygen migrations.
文摘The earliest written record of the term “Kaxabu” dates to the 1908 survey report by the Japanese scholar Ino Kanori. In his study of the Pazzehe tribe in central Taiwan, he wrote: “Kaxabu was the name given by the Pazzehe to Daiyao'puru, a small division of its ethnic group.” During the Qing era, the Pazzehe was called the Anli group by Chinese speakers in Taiwan, while the Kaxabu were named Puzili she (the Puzili tribe). Since the Kaxabu originated from the Pazzehe, thus in determining the time when the Kaxabu became distinct from the Pazzehe and in exploring the differences between them, we will also elucidate historical developments before the Japanese colonial era. Using Qing historical materials such as travelogues, expedition-records, newspapers, data from fieldwork, surveys, and interviews, this study traces the intervention of the Qing court into tribal relationships in central Taiwan, beginning with the Dajiaxi she Incident (1731-32), it touches on the changing environment of the Kaxabu/ Puzili she in their migrations in order to shed light on the development of the two distinctive identities-the Kaxabu and Pazzehe/Anli group. The analysis also reveals the impact of uprisings and migrations upon the border area surrounding Qing Taiwan, as well as problems of ethnic identification and geography.