Limited research has been conducted on the influences of fiber content on close-in blasting characteristics for ultrahigh-performance fiber-reinforced concrete(UHPFRC)beams.This paper aims to address this knowledge ga...Limited research has been conducted on the influences of fiber content on close-in blasting characteristics for ultrahigh-performance fiber-reinforced concrete(UHPFRC)beams.This paper aims to address this knowledge gap through experimental and mesoscale numerical methods.Experiments were conducted on ten UHPFRC beams built with varying steel fiber volumetric fractions subjected to close-in explosive conditions.Additionally,this study considered other parameters,such as the longitudinal reinforcement type and ratio.In the case of UHPFRC beams featuring normal-strength longitudinal reinforcement of diametersΦ12,Φ16,andΦ20,a reduction in maximum displacement by magnitudes of19.6%,19.5%,and 17.4%was observed,respectively,as the volumetric fractions of fiber increased from1.0%to 2.5%.In addition,increasing the longitudinal reinforcement ratio and using high-strength steel longitudinal reinforcement both significantly reduced the deformation characteristics and increase the blasting resistances of UHPFRC beams.However,the effects on the local crushing and spalling damage were not significant.A mesoscale finite element model,which considers the impacts of fiber parameters on UHPFRC beam behaviors,was also established and well correlated with the test findings.Nevertheless,parametric analyses were further conducted to examine the impacts of the steel fiber content and length and the hybrid effects of various types of microfibers and steel fibers on the blasting performance of UHPFRC beams.展开更多
Taking CL-20(Hexanitrohexaazaisowurtzitane)-based aluminized explosives with high gurney energy as the research object, this research experimentally investigates the work capability of different aluminized explosive f...Taking CL-20(Hexanitrohexaazaisowurtzitane)-based aluminized explosives with high gurney energy as the research object, this research experimentally investigates the work capability of different aluminized explosive formulations when driving metal flyer plates in the denotation wave propagation direction.The research results showed that the formulations with 43 μm aluminum(Al) powder particles(The particle sizes of Al powder were in the range of 2~43 μm) exhibited the optimal performance in driving flyer plates along the denotation wave propagation direction. Compared to the formulations with Al powder 13 μm, the formulations with Al powder 2 μm delivered better performance in accelerating metal flyer plates in the early stage, which, however, turned to be poor in the later stage. The CL-20-based explosives containing 25% Al far under-performed those containing 15% Al. Based on the proposed quasi-isentropic hypothesis, relevant isentropy theories, and the functional relationship between detonation parameters and entropy as well as Al reaction degree, the characteristic lines of aluminized explosives in accelerating flyer plates were theoretically studied, a quasi-isentropic theoretical model for the aluminized explosive driving the flyer plate was built and the calculation methods for the variations of flyer plate velocity, Al reaction degree, and detonation product parameters with time and axial positions were developed. The theoretical model built is verified by the experimental results of the CL-20-based aluminized explosive driving flyer plate. It was found that the model built could accurately calculate the variations of flyer plate velocity and Al reaction degree over time. In addition, how physical parameters including detonation product pressure and temperature varied with time and axial positions was identified. The action time of the positive pressure after the detonation of aluminized explosives was found prolonged and the downtrend of the temperature was slowed down and even reversed to a slight rise due to the aftereffect reaction between the Al powder and the detonation products.展开更多
Circulating tumor cells(CTCs) are a population of tumor cells mediating metastasis, which results in most of the cancer related deaths. The number of CTCs in the peripheral blood of patients is rare, and many platform...Circulating tumor cells(CTCs) are a population of tumor cells mediating metastasis, which results in most of the cancer related deaths. The number of CTCs in the peripheral blood of patients is rare, and many platforms have been launched for detection and enrichment of CTCs. Enumeration of CTCs has already been used as a prognosis marker predicting the survival rate of cancer patients. Yet CTCs should be more potential. Studies on CTCs at single cell level may help revealing the underlying mechanism of tumorigenesis and metastasis. Though far from developed, this area of study holds much promise in providing new clinical application and deep understanding towards metastasis and cancer development.展开更多
Currently,developing supercapacitors with robust cycle stability and suitability for wide-temperature-range operations is still a huge challenge.In the present work,few-layer hexagonal boron nitride nanosheets(h-BNNSs...Currently,developing supercapacitors with robust cycle stability and suitability for wide-temperature-range operations is still a huge challenge.In the present work,few-layer hexagonal boron nitride nanosheets(h-BNNSs)with a thickness of 2−4 atomic layers were fabricated via vacuum freeze-drying and nitridation.Then,the h-BNNSs/reduced graphene oxide(rGO)composite were further prepared using a hydrothermal method.Due to the combination of two two-dimensional(2D)van der Waals-bonded materials,the as-prepared h-BNNSs/rGO electrode exhibited robustness to wide-temperature-range operations from−10 to 50℃.When the electrodes worked in a neutral aqueous electrolyte(1 M Na2SO4),they showed a great stable cycling performance with almost 107%reservation of the initial capacitance at 0℃ and 111% at 50℃ for 5000 charge−discharge cycles.展开更多
As fixed compression ratio is used in traditional deep space exploration image transmission application,the same compression code rate is allocated to each image.However,since the information of each image in a space ...As fixed compression ratio is used in traditional deep space exploration image transmission application,the same compression code rate is allocated to each image.However,since the information of each image in a space observation mission is nonuniform,the image with more information will inevitably lead to more compression distortion than the image with less information.Obviously,it’s not an efficient way to transmit information in terms of data importance or overall distortion.Therefore,we proposed a combinatorial optimal bit rate allocation algorithm to improve the efficiency of image transmission in space application.Different from traditional method,the rate-distortion model of wavelet coefficients for each image in a transmission task was built,and under the overall maximum transmission rate constraint,an bit-rate optimal allocation was applied for each image to minimize the overall distortion of a batch of images.The proposed algorithm can be widely used in image compression algorithm with embedded code stream characteristics,such as JPEG2000 and SPIHT.Experimental results shows that in the range of 2.6 to 10 compression ratio,the algorithm can reduce image distortion MSB by 40%~64%at the same overall transmission code rate,which equivalent to improvement of PSNR 3 dB to 5.4 dB.展开更多
Introduction Primary liver cancer,the second most common cause of cancer related death worldwide1,presents ethnic,etiological,sex,and geographical diversity2(Figure 1A).At the histological level,liver cancer includes ...Introduction Primary liver cancer,the second most common cause of cancer related death worldwide1,presents ethnic,etiological,sex,and geographical diversity2(Figure 1A).At the histological level,liver cancer includes two major types:hepatocellular carcinoma(HCC,about 80%)and cholangiocarcinoma(CCA,about 15%).Many etiological factors contribute to HCC development,such as hepatitis展开更多
The interaction of MeV H2^+ molecular ions with thin layer graphene and graphite foils was studied by using a highresolution electrostatic analyzer.A large number of fragment protons were observed at zero degree(along...The interaction of MeV H2^+ molecular ions with thin layer graphene and graphite foils was studied by using a highresolution electrostatic analyzer.A large number of fragment protons were observed at zero degree(along the beam direction) when the H2^+ beam was passing through the monolayer graphene foil, which indicates that the electron of the H2^+ molecular ions can be stripped easily even by the monolayer graphene foil.More trailing than leading protons were found in the energy spectrum, which means significant wake effect was observed in the monolayer graphene foil.The ratio of the numbers of trailing protons over leading protons first increased with the thickness for the much thinner graphene foils, and then decreased with the thickness for the much thicker graphite foils, which indicates that the bending effect of the wake field on the trailing proton varied with the foil thickness.展开更多
A quasi-isentropic study on the process of driving a cylinder with aluminized explosives was carried out to examine the influence of the aluminum(Al) reaction rate on cylinder expansion and the physical parameters of ...A quasi-isentropic study on the process of driving a cylinder with aluminized explosives was carried out to examine the influence of the aluminum(Al) reaction rate on cylinder expansion and the physical parameters of the detonation products. Based on the proposed quasi-isentropic hypothesis and relevant isentropic theories, the characteristic lines of aluminized explosives driving a cylinder were analyzed,and a quasi-isentropic model was established. This model includes the variation of the cylinder wall velocity and the physical parameters of the detonation products with the Al reaction degree. Using previously reported experimental results, the quasi-isentropic model was verified to be applicative and accurate. This model was used to calculate the physical parameters for cylinder experiments with aluminized cyclotrimethylenetrinitramine explosives with 15.0 % and 30.0 % Al content. The results show that this quasi-isentropic model can be used not only to calculate the cylinder expansion rule or Al reaction degree, but also to calculate the physical parameters of the detonation products in the process of cylinder expansion. For explosives with 15.0 % and 30.0 % Al, 24.3 % and 18.5 % of the Al was found to have reacted at 33.9 μs and 34.0 μs, respectively. The difference in Al content results in different reaction intensity, occurrence time, and duration of two forms of reaction(diffusion and kinetic) between the Al powder and the detonation products;the post-detonation burning reaction between the Al powder and the detonation products prolongs the positive pressure action time, resulting in a continuous rise in temperature after detonation.展开更多
Objective: Previous investigations of circulating tumor cells(CTCs) have mainly focused on their genomic or transcriptomic features, leaving their epigenetic landscape relatively uncharacterized. Here, we investigated...Objective: Previous investigations of circulating tumor cells(CTCs) have mainly focused on their genomic or transcriptomic features, leaving their epigenetic landscape relatively uncharacterized. Here, we investigated the genome-wide DNA methylome of CTCs with a view to understanding the epigenetic regulatory mechanisms underlying cancer metastasis.Methods: We evaluated single-cell DNA methylome and copy number alteration(CNA) in 196 single cells,including 107 CTCs collected from 17 cancer patients covering six different cancer types. Our single-cell bisulfite sequencing(sc BS-seq) covered on average 11.78% of all Cp G dinucleotides and accurately deduced the CNA patterns at 500 kb resolution.Results: We report distinct subclonal structures and different evolutionary histories of CTCs inferred from CNA and DNA methylation profiles. Furthermore, we demonstrate potential tumor origin classification based on the tissue-specific DNA methylation profiles of CTCs.Conclusions: Our work provides a comprehensive survey of genome-wide DNA methylome in single CTCs and reveals 5-methylcytosine(5-m C) heterogeneity in CTCs, addressing the potential epigenetic regulatory mechanisms underlying cancer metastasis and facilitating the future clinical application of CTCs.展开更多
Spinal cord injury (SCI) impairs the au-tonomic nervous system and is associated with dysfunc-tion or failure of multiple organs. Rehabilitation after SCI is a complicated process that involves improvement of motor an...Spinal cord injury (SCI) impairs the au-tonomic nervous system and is associated with dysfunc-tion or failure of multiple organs. Rehabilitation after SCI is a complicated process that involves improvement of motor and sensory function and amelioration of com-plications. Accumulating evidence has demonstrated that melatonin treatment could protect the neural tissues of the spinal cord from secondary injury after SCI. Melatonin is an indoleamine naturally produced by the pineal gland and other tissues. It can easily cross the blood-brain bar-rier and has been shown to have neuroprotective proper-ties in animal models with neurological injury, such as traumatic brain injury and SCI. We reviewed the potential mechanisms of melatonin treatment reducing SCI-relat-ed complications such as disruption of microcirculation, neurogenic bowel dysfunction, and circadian disorders.展开更多
CRISPR interference(CRISPRi)has been developed and widely used for gene repression in various hosts.Here we report an improved CRISPRi system in Pichia pastoris by fusing dCas9 with endogenous transcriptional represso...CRISPR interference(CRISPRi)has been developed and widely used for gene repression in various hosts.Here we report an improved CRISPRi system in Pichia pastoris by fusing dCas9 with endogenous transcriptional repressor domains.The CRISPRi system shows strong repression of eGFP,with the highest efficiency of 85%.Repression of native genes is demonstrated by targeting AOX1 promoter.AOX1 is efficiently repressed and the mutant strains show much slower growth in methanol medium.Effects of gRNA expression and processing on CRISPRi efficiency is also investigated.It is found that gRNA processing by HH/HDV ribozymes or Csy4 endoribonuclease generating clean gRNA is critical to achieve strong repression,and Csy4 cleavage shows higher repression efficiency.However,gRNA expression using native tRNA transcription and processing systems results in relatively weaker repression of eGFP.By expression of two gRNAs targeting promoters of eGFP and AOX1 in an array together with Cys4 recognition sites,both genes can be repressed simultaneously.Cys4-mediated gRNA array processing is further applied to repress fatty acyl-CoA synthetase genes(FAA1 and FAA2).Both genes are efficiently repressed,demonstrating that Cys4 endoribonuclease has the ability to cleave gRNAs array and can be can be used for multiplexed gene repression in P.pastoris.展开更多
The treatment of Manske type IIIB and IV thumb hypoplasia remains controversial,and parents increasingly expect to maintain the hypoplastic thumb in preference to a five-digit hand.[1,2]There has been a recent increas...The treatment of Manske type IIIB and IV thumb hypoplasia remains controversial,and parents increasingly expect to maintain the hypoplastic thumb in preference to a five-digit hand.[1,2]There has been a recent increased number of reports regarding the reconstruction of severe thumb hypoplasia with the use of free metatarsal transfers(MTs).Tsujino et al[3]reconstructed a thumb with a nonvascularized 4th metatarsal,and filled the bone defect with an iliac graft.Chow et al[4]reported on thumb reconstruction with hemi-width MT,which reduced not only the sacrifice of the donor foot but also the strength of the reconstructed metacarpal.展开更多
Bubonic plague caused by Yersinia pestis is highly infectious and often fatal.Characterization of the host immune response and its subsequent suppression by Y.pestis is critical to understanding the pathogenesis of Y....Bubonic plague caused by Yersinia pestis is highly infectious and often fatal.Characterization of the host immune response and its subsequent suppression by Y.pestis is critical to understanding the pathogenesis of Y.pestis.Here,we utilized single-cell RNA sequencing to systematically profile the transcriptomes of immune cells in draining lymph nodes(d LNs)during the early stage of Y.pestis infection.Dendritic cells responded to Y.pestis within 2 h post-infection(hpi),followed by the activation of macrophages/monocytes(Mφs/Mons)and recruitment of polymorphonuclear neutrophils(PMNs)to d LNs at 24 hpi.Analysis of cell-to-cell communication suggests that PMNs may be recruited to lymph nodes following the secretion of CCL9 by Mφs/Mons stimulated through CCR1-CCL9 interaction.Significant functional suppression of all the three innate immune cell types occurred during the early stage of infection.In summary,we present a dynamic immune landscape,at single-cell resolution,of murine d LNs involved in the response to Y.pestis infection,which may facilitate the understanding of the plague pathogenesis of during the early stage of infection.展开更多
Aerobic composting is a method for the sanitary disposal of human feces as is used in bio-toilet systems.As the products of composting can be utilized as a fertilizer,it would be beneficial if the composting condition...Aerobic composting is a method for the sanitary disposal of human feces as is used in bio-toilet systems.As the products of composting can be utilized as a fertilizer,it would be beneficial if the composting conditions could be more precisely controlled for the retention of fecal nitrogen as long as possible in the compost.In this study,batch experiments were conducted using a closed aerobic thermophilic composting reactor with sawdust as the bulk matrix to simulate the condition of a bio-toilet for the sanitary disposal of human feces.Attention was paid to the characteristics of nitrogen transformation.Under the controlled conditions of temperature at 60°C,moisture content at 60%,and a continuous air supply,more than 70%fecal organic removal was obtained,while merely 17%fecal nitrogen loss was observed over a two-week composting period.The nitrogen loss was found to occur mainly in the first 24 h with the rapid depletion of inorganic nitrogen but with an almost unchanged organic nitrogen content.The fecal NH4-N which was the main component of the inorganic nitrogen(>90%)decreased rapidly in the first day,decreased at a slower rate over the following days,and finally disappeared entirely.The depletion of NH4-N was accompanied by the accumulation of NH3 gas in the ammonia absorber connected to the reactor.A mass balance between the exhausted NH3 gas and the fecal NH4-N content in the first 24 hours indicated that the conversion of ammonium into gaseous ammonia was the main reason for nitrogen loss.Thermophilic composting could be considered as a way to keep a high organic nitrogen content in the compost for better utilization as a fertilizer.展开更多
Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection can cause acute respiratory distress syndrome,hypercoagulability,hypertension,and multiorgan dysfunction.Effective antivirals with safe clinical pro...Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection can cause acute respiratory distress syndrome,hypercoagulability,hypertension,and multiorgan dysfunction.Effective antivirals with safe clinical profile are urgently needed to improve the overall prognosis.In an analysis of a randomly collected cohort of 124 patients with COVID-19,we found that hypercoagulability as indicated by elevated concentrations of D-dimers was associated with disease severity.By virtual screening of a U.S.FDA approved drug library,we identified an anticoagulation agent dipyridamole(DIP)in silico,which suppressed SARS-CoV-2 replication in vitro.In a proof-of-concept trial involving 31 patients with COVID-19,DIP supplementation was associated with significantly decreased concentrations of D-dimers(P<0.05),increased lymphocyte and platelet recovery in the circulation,and markedly improved clinical outcomes in comparison to the control patients.In particular,all 8 of the DIP-treated severely ill patients showed remarkable improvement:7 patients(87.5%)achieved clinical cure and were discharged from the hospitals while the remaining 1 patient(12.5%)was in clinical remission.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.12102050)the Open Fund of State Key Laboratory of Explosion Science and Technology(Grant No.SKLEST-ZZ-21-18)。
文摘Limited research has been conducted on the influences of fiber content on close-in blasting characteristics for ultrahigh-performance fiber-reinforced concrete(UHPFRC)beams.This paper aims to address this knowledge gap through experimental and mesoscale numerical methods.Experiments were conducted on ten UHPFRC beams built with varying steel fiber volumetric fractions subjected to close-in explosive conditions.Additionally,this study considered other parameters,such as the longitudinal reinforcement type and ratio.In the case of UHPFRC beams featuring normal-strength longitudinal reinforcement of diametersΦ12,Φ16,andΦ20,a reduction in maximum displacement by magnitudes of19.6%,19.5%,and 17.4%was observed,respectively,as the volumetric fractions of fiber increased from1.0%to 2.5%.In addition,increasing the longitudinal reinforcement ratio and using high-strength steel longitudinal reinforcement both significantly reduced the deformation characteristics and increase the blasting resistances of UHPFRC beams.However,the effects on the local crushing and spalling damage were not significant.A mesoscale finite element model,which considers the impacts of fiber parameters on UHPFRC beam behaviors,was also established and well correlated with the test findings.Nevertheless,parametric analyses were further conducted to examine the impacts of the steel fiber content and length and the hybrid effects of various types of microfibers and steel fibers on the blasting performance of UHPFRC beams.
基金National Natural Science Foundation of China(Grant No.11872120).
文摘Taking CL-20(Hexanitrohexaazaisowurtzitane)-based aluminized explosives with high gurney energy as the research object, this research experimentally investigates the work capability of different aluminized explosive formulations when driving metal flyer plates in the denotation wave propagation direction.The research results showed that the formulations with 43 μm aluminum(Al) powder particles(The particle sizes of Al powder were in the range of 2~43 μm) exhibited the optimal performance in driving flyer plates along the denotation wave propagation direction. Compared to the formulations with Al powder 13 μm, the formulations with Al powder 2 μm delivered better performance in accelerating metal flyer plates in the early stage, which, however, turned to be poor in the later stage. The CL-20-based explosives containing 25% Al far under-performed those containing 15% Al. Based on the proposed quasi-isentropic hypothesis, relevant isentropy theories, and the functional relationship between detonation parameters and entropy as well as Al reaction degree, the characteristic lines of aluminized explosives in accelerating flyer plates were theoretically studied, a quasi-isentropic theoretical model for the aluminized explosive driving the flyer plate was built and the calculation methods for the variations of flyer plate velocity, Al reaction degree, and detonation product parameters with time and axial positions were developed. The theoretical model built is verified by the experimental results of the CL-20-based aluminized explosive driving flyer plate. It was found that the model built could accurately calculate the variations of flyer plate velocity and Al reaction degree over time. In addition, how physical parameters including detonation product pressure and temperature varied with time and axial positions was identified. The action time of the positive pressure after the detonation of aluminized explosives was found prolonged and the downtrend of the temperature was slowed down and even reversed to a slight rise due to the aftereffect reaction between the Al powder and the detonation products.
文摘Circulating tumor cells(CTCs) are a population of tumor cells mediating metastasis, which results in most of the cancer related deaths. The number of CTCs in the peripheral blood of patients is rare, and many platforms have been launched for detection and enrichment of CTCs. Enumeration of CTCs has already been used as a prognosis marker predicting the survival rate of cancer patients. Yet CTCs should be more potential. Studies on CTCs at single cell level may help revealing the underlying mechanism of tumorigenesis and metastasis. Though far from developed, this area of study holds much promise in providing new clinical application and deep understanding towards metastasis and cancer development.
基金financially supported by the National Natural Science Foundation for Excellent Young Scholars of China (No. 51522402)the National Postdoctoral Program for Innovative Talents of China (No. BX20180034)+2 种基金the National Natural Science Foundation of China (No. 51902020)the Fundamental Research Funds for the Central Universities (No. FRF-TP-18-045A1)the China Postdoctoral Science Foundation (No. 2018M641192)
文摘Currently,developing supercapacitors with robust cycle stability and suitability for wide-temperature-range operations is still a huge challenge.In the present work,few-layer hexagonal boron nitride nanosheets(h-BNNSs)with a thickness of 2−4 atomic layers were fabricated via vacuum freeze-drying and nitridation.Then,the h-BNNSs/reduced graphene oxide(rGO)composite were further prepared using a hydrothermal method.Due to the combination of two two-dimensional(2D)van der Waals-bonded materials,the as-prepared h-BNNSs/rGO electrode exhibited robustness to wide-temperature-range operations from−10 to 50℃.When the electrodes worked in a neutral aqueous electrolyte(1 M Na2SO4),they showed a great stable cycling performance with almost 107%reservation of the initial capacitance at 0℃ and 111% at 50℃ for 5000 charge−discharge cycles.
文摘As fixed compression ratio is used in traditional deep space exploration image transmission application,the same compression code rate is allocated to each image.However,since the information of each image in a space observation mission is nonuniform,the image with more information will inevitably lead to more compression distortion than the image with less information.Obviously,it’s not an efficient way to transmit information in terms of data importance or overall distortion.Therefore,we proposed a combinatorial optimal bit rate allocation algorithm to improve the efficiency of image transmission in space application.Different from traditional method,the rate-distortion model of wavelet coefficients for each image in a transmission task was built,and under the overall maximum transmission rate constraint,an bit-rate optimal allocation was applied for each image to minimize the overall distortion of a batch of images.The proposed algorithm can be widely used in image compression algorithm with embedded code stream characteristics,such as JPEG2000 and SPIHT.Experimental results shows that in the range of 2.6 to 10 compression ratio,the algorithm can reduce image distortion MSB by 40%~64%at the same overall transmission code rate,which equivalent to improvement of PSNR 3 dB to 5.4 dB.
基金supported,in part,by the Precision Medical Research Program from Ministry of Science and Technology of China(Grant No.YL 2017YFC0908400)National Science and Technology Major Project for Infectious Disease and Funding(Grant No.YL 17-163-12-ZT-005-095-01)+2 种基金Science and Technology Commission in Ministry of National Defense of China(Grant No.YL 17-163-12-ZT-005-095-01)Xinwei Wang was supported by the intramural research program of the Center for Cancer Research,National Cancer Institute of the United StatesJunfang Ji was supported by the Thousand Young Talents Plan of China,National Natural Science Foundation of China(Grant No.81672905)
文摘Introduction Primary liver cancer,the second most common cause of cancer related death worldwide1,presents ethnic,etiological,sex,and geographical diversity2(Figure 1A).At the histological level,liver cancer includes two major types:hepatocellular carcinoma(HCC,about 80%)and cholangiocarcinoma(CCA,about 15%).Many etiological factors contribute to HCC development,such as hepatitis
基金Project supported by the National Natural Science Foundation of China(Grant No.11575121)the National Magnetic Confinement Fusion Program of China(Grant No.2014GB125004)
文摘The interaction of MeV H2^+ molecular ions with thin layer graphene and graphite foils was studied by using a highresolution electrostatic analyzer.A large number of fragment protons were observed at zero degree(along the beam direction) when the H2^+ beam was passing through the monolayer graphene foil, which indicates that the electron of the H2^+ molecular ions can be stripped easily even by the monolayer graphene foil.More trailing than leading protons were found in the energy spectrum, which means significant wake effect was observed in the monolayer graphene foil.The ratio of the numbers of trailing protons over leading protons first increased with the thickness for the much thinner graphene foils, and then decreased with the thickness for the much thicker graphite foils, which indicates that the bending effect of the wake field on the trailing proton varied with the foil thickness.
基金National Natural Science Foundation of China(Grant No.11872120).
文摘A quasi-isentropic study on the process of driving a cylinder with aluminized explosives was carried out to examine the influence of the aluminum(Al) reaction rate on cylinder expansion and the physical parameters of the detonation products. Based on the proposed quasi-isentropic hypothesis and relevant isentropic theories, the characteristic lines of aluminized explosives driving a cylinder were analyzed,and a quasi-isentropic model was established. This model includes the variation of the cylinder wall velocity and the physical parameters of the detonation products with the Al reaction degree. Using previously reported experimental results, the quasi-isentropic model was verified to be applicative and accurate. This model was used to calculate the physical parameters for cylinder experiments with aluminized cyclotrimethylenetrinitramine explosives with 15.0 % and 30.0 % Al content. The results show that this quasi-isentropic model can be used not only to calculate the cylinder expansion rule or Al reaction degree, but also to calculate the physical parameters of the detonation products in the process of cylinder expansion. For explosives with 15.0 % and 30.0 % Al, 24.3 % and 18.5 % of the Al was found to have reacted at 33.9 μs and 34.0 μs, respectively. The difference in Al content results in different reaction intensity, occurrence time, and duration of two forms of reaction(diffusion and kinetic) between the Al powder and the detonation products;the post-detonation burning reaction between the Al powder and the detonation products prolongs the positive pressure action time, resulting in a continuous rise in temperature after detonation.
基金financially supported by the Guangdong Province Key Research and Development Program (No. 2019B020226002)the National Science and Technology Major Project (No. 2019YFC1315702)。
文摘Objective: Previous investigations of circulating tumor cells(CTCs) have mainly focused on their genomic or transcriptomic features, leaving their epigenetic landscape relatively uncharacterized. Here, we investigated the genome-wide DNA methylome of CTCs with a view to understanding the epigenetic regulatory mechanisms underlying cancer metastasis.Methods: We evaluated single-cell DNA methylome and copy number alteration(CNA) in 196 single cells,including 107 CTCs collected from 17 cancer patients covering six different cancer types. Our single-cell bisulfite sequencing(sc BS-seq) covered on average 11.78% of all Cp G dinucleotides and accurately deduced the CNA patterns at 500 kb resolution.Results: We report distinct subclonal structures and different evolutionary histories of CTCs inferred from CNA and DNA methylation profiles. Furthermore, we demonstrate potential tumor origin classification based on the tissue-specific DNA methylation profiles of CTCs.Conclusions: Our work provides a comprehensive survey of genome-wide DNA methylome in single CTCs and reveals 5-methylcytosine(5-m C) heterogeneity in CTCs, addressing the potential epigenetic regulatory mechanisms underlying cancer metastasis and facilitating the future clinical application of CTCs.
文摘Spinal cord injury (SCI) impairs the au-tonomic nervous system and is associated with dysfunc-tion or failure of multiple organs. Rehabilitation after SCI is a complicated process that involves improvement of motor and sensory function and amelioration of com-plications. Accumulating evidence has demonstrated that melatonin treatment could protect the neural tissues of the spinal cord from secondary injury after SCI. Melatonin is an indoleamine naturally produced by the pineal gland and other tissues. It can easily cross the blood-brain bar-rier and has been shown to have neuroprotective proper-ties in animal models with neurological injury, such as traumatic brain injury and SCI. We reviewed the potential mechanisms of melatonin treatment reducing SCI-relat-ed complications such as disruption of microcirculation, neurogenic bowel dysfunction, and circadian disorders.
基金National Key Research and Development Program of China(2021YFC2103500)Dalian Institute of Chemical Physics Innovation Program(DICP I202111).
文摘CRISPR interference(CRISPRi)has been developed and widely used for gene repression in various hosts.Here we report an improved CRISPRi system in Pichia pastoris by fusing dCas9 with endogenous transcriptional repressor domains.The CRISPRi system shows strong repression of eGFP,with the highest efficiency of 85%.Repression of native genes is demonstrated by targeting AOX1 promoter.AOX1 is efficiently repressed and the mutant strains show much slower growth in methanol medium.Effects of gRNA expression and processing on CRISPRi efficiency is also investigated.It is found that gRNA processing by HH/HDV ribozymes or Csy4 endoribonuclease generating clean gRNA is critical to achieve strong repression,and Csy4 cleavage shows higher repression efficiency.However,gRNA expression using native tRNA transcription and processing systems results in relatively weaker repression of eGFP.By expression of two gRNAs targeting promoters of eGFP and AOX1 in an array together with Cys4 recognition sites,both genes can be repressed simultaneously.Cys4-mediated gRNA array processing is further applied to repress fatty acyl-CoA synthetase genes(FAA1 and FAA2).Both genes are efficiently repressed,demonstrating that Cys4 endoribonuclease has the ability to cleave gRNAs array and can be can be used for multiplexed gene repression in P.pastoris.
文摘The treatment of Manske type IIIB and IV thumb hypoplasia remains controversial,and parents increasingly expect to maintain the hypoplastic thumb in preference to a five-digit hand.[1,2]There has been a recent increased number of reports regarding the reconstruction of severe thumb hypoplasia with the use of free metatarsal transfers(MTs).Tsujino et al[3]reconstructed a thumb with a nonvascularized 4th metatarsal,and filled the bone defect with an iliac graft.Chow et al[4]reported on thumb reconstruction with hemi-width MT,which reduced not only the sacrifice of the donor foot but also the strength of the reconstructed metacarpal.
文摘Bubonic plague caused by Yersinia pestis is highly infectious and often fatal.Characterization of the host immune response and its subsequent suppression by Y.pestis is critical to understanding the pathogenesis of Y.pestis.Here,we utilized single-cell RNA sequencing to systematically profile the transcriptomes of immune cells in draining lymph nodes(d LNs)during the early stage of Y.pestis infection.Dendritic cells responded to Y.pestis within 2 h post-infection(hpi),followed by the activation of macrophages/monocytes(Mφs/Mons)and recruitment of polymorphonuclear neutrophils(PMNs)to d LNs at 24 hpi.Analysis of cell-to-cell communication suggests that PMNs may be recruited to lymph nodes following the secretion of CCL9 by Mφs/Mons stimulated through CCR1-CCL9 interaction.Significant functional suppression of all the three innate immune cell types occurred during the early stage of infection.In summary,we present a dynamic immune landscape,at single-cell resolution,of murine d LNs involved in the response to Y.pestis infection,which may facilitate the understanding of the plague pathogenesis of during the early stage of infection.
基金the National Natural Science Foundation of China(Grant No.51021140002)the National Program of Water Pollution Control(No.2008ZX07317-004)the Program for Changjiang Scholars and Innovative Research Team in University(No.IRT0853)。
文摘Aerobic composting is a method for the sanitary disposal of human feces as is used in bio-toilet systems.As the products of composting can be utilized as a fertilizer,it would be beneficial if the composting conditions could be more precisely controlled for the retention of fecal nitrogen as long as possible in the compost.In this study,batch experiments were conducted using a closed aerobic thermophilic composting reactor with sawdust as the bulk matrix to simulate the condition of a bio-toilet for the sanitary disposal of human feces.Attention was paid to the characteristics of nitrogen transformation.Under the controlled conditions of temperature at 60°C,moisture content at 60%,and a continuous air supply,more than 70%fecal organic removal was obtained,while merely 17%fecal nitrogen loss was observed over a two-week composting period.The nitrogen loss was found to occur mainly in the first 24 h with the rapid depletion of inorganic nitrogen but with an almost unchanged organic nitrogen content.The fecal NH4-N which was the main component of the inorganic nitrogen(>90%)decreased rapidly in the first day,decreased at a slower rate over the following days,and finally disappeared entirely.The depletion of NH4-N was accompanied by the accumulation of NH3 gas in the ammonia absorber connected to the reactor.A mass balance between the exhausted NH3 gas and the fecal NH4-N content in the first 24 hours indicated that the conversion of ammonium into gaseous ammonia was the main reason for nitrogen loss.Thermophilic composting could be considered as a way to keep a high organic nitrogen content in the compost for better utilization as a fertilizer.
基金National Key R&D Program of China(2017YFB0202600 and 2020YFC0841400)National Natural Science Foundation of China(91742109,8152204,31770978,81773674,and 21877134)+8 种基金National Health&Medical Research of Australia(1080321,1143976 and 1150425)Science Foundation of Guangzhou City(201904020023,China)Guangdong Province Higher Vocational Colleges and Schools Pearl River Scholar Funded Scheme(2016 and 2019,China)Guangdong Provincial Key Laboratory of Construction Foundation(2017B030314030,China)Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2017BT01Y093,China)Zhejiang University special scientific research fund for COVID-19 prevention and control(China)National Health&Medical Research of Australia(1080321,1143976,and 1150425)Taikang Insurance Group Co.,Ltd.Beijing Taikang Yicai Foundation(Beijing,China)
文摘Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection can cause acute respiratory distress syndrome,hypercoagulability,hypertension,and multiorgan dysfunction.Effective antivirals with safe clinical profile are urgently needed to improve the overall prognosis.In an analysis of a randomly collected cohort of 124 patients with COVID-19,we found that hypercoagulability as indicated by elevated concentrations of D-dimers was associated with disease severity.By virtual screening of a U.S.FDA approved drug library,we identified an anticoagulation agent dipyridamole(DIP)in silico,which suppressed SARS-CoV-2 replication in vitro.In a proof-of-concept trial involving 31 patients with COVID-19,DIP supplementation was associated with significantly decreased concentrations of D-dimers(P<0.05),increased lymphocyte and platelet recovery in the circulation,and markedly improved clinical outcomes in comparison to the control patients.In particular,all 8 of the DIP-treated severely ill patients showed remarkable improvement:7 patients(87.5%)achieved clinical cure and were discharged from the hospitals while the remaining 1 patient(12.5%)was in clinical remission.
