Tracking multiple space objects using multiple surveillance sensors is a critical approach in many Space Situation Awareness(SSA) applications. In this process, the uncertainties of targets,dynamics, and observations ...Tracking multiple space objects using multiple surveillance sensors is a critical approach in many Space Situation Awareness(SSA) applications. In this process, the uncertainties of targets,dynamics, and observations are usually represented by the probability distributions. However, precise characterization of uncertainty becomes challenging due to imperfect knowledge about some key aspects, such as birth targets and sensor detection profiles. To overcome this challenge, this paper proposes a multi-sensor possibility PHD filter based on the theory of outer probability measures. An effective compensation method is introduced to tackle variations in the fields of view of SSA sensors or instances of missed detections, aiming to mitigate the inconsistency in localized information. The proposed method is adapted to centralized and distributed sensor networks, offering effective solutions for multi-sensor multi-target tracking. The major innovation of the proposed method compared with typical methods is the proper description of epistemic uncertainty, which yields more robust performance in the scenarios of lacking some information about the system.The effectiveness of the multi-sensor possibility PHD filter is demonstrated by a comparison with conventional methods in two simulated scenarios.展开更多
To develop smart and efficient near-infrared(NIR)organic dyes for photothermal cancer therapy is of great challenge.Herein,a pH-sensitive NIR dye BTN with donor–acceptor–donor scaffold has been synthesized.Two perip...To develop smart and efficient near-infrared(NIR)organic dyes for photothermal cancer therapy is of great challenge.Herein,a pH-sensitive NIR dye BTN with donor–acceptor–donor scaffold has been synthesized.Two periphery electron-donating dimethylamine groups in BTN can not only promote the intramolecular photoinduced electron transfer(PET),but also bind protons to transform into electron-deficient ammonium cation for enhanced intramolecular charge transfer(ICT)under acidic circumstance.Through enveloping with amphiphilic polymeric 1,2-distearoyl-ras-glycerol-3-phosphatidyl ethanolamine-N-polyethyleneglycol-2000(DSPE-mPEG2000),BTN nanoparticles(NPs)were fabricated with robust NIR absorption covering 600–900 nm,excellent photothermal conversion efficiency(43.2%),and good photostability.Additionally,BTN NPs can selectively target lysosomes.Through tailing intravenous injection into tumor-bearing nude mice,BTN NPs demonstrate outstanding photoacoustic/photothermal/fluorescence imaging-guided photothermal therapy for tumor ablation.展开更多
Drought-induced protein 19(Di19) is a Cys2/His2 zinc-finger protein that functions in plant growth and development and in tolerance to abiotic stresses.Gm PUB21,an E3 ubiquitin ligase,negatively regulates drought and ...Drought-induced protein 19(Di19) is a Cys2/His2 zinc-finger protein that functions in plant growth and development and in tolerance to abiotic stresses.Gm PUB21,an E3 ubiquitin ligase,negatively regulates drought and salinity response in soybean.We identified potential interaction target proteins of Gm PUB21by yeast two-hybrid c DNA library screening,Gm Di19-5 as a candidate.Bimolecular fluorescence complementation and glutathionine-S-transferase pull-down assays confirmed the interaction between Gm Di19-5 and Gm PUB21.Gm Di19-5 was induced by Na Cl,drought,and abscisic acid(ABA) treatments.Gm Di19-5 was expressed in the cytoplasm and nucleus.Gm Di19-5 overexpression conferred hypersensitivity to drought and high salinity,whereas Gm Di19-5 silencing increased drought and salinity tolerance.Transcripts of ABA-and stress response-associated genes including Gm RAB18 and Gm DREB2A were downregulated in Gm Di19-5-overexpressing plants under drought and salinity stresses.ABA decreased the protein level of Gm Di19-5 in vivo,whereas Gm PUB21 increased the decrease of Gm Di19-5 after exogenous ABA application.The accumulation of Gm PUB21 was also inhibited by Gm Di19-5.We conclude that Gm PUB21 and Gm Di19-5 collaborate to regulate drought and salinity tolerance via an ABA-dependent pathway.展开更多
Background Several studies have shown that afternoon napping promotes cognitive function in the elderly;on the other hand,some studies have shown opposite results.This current study further examined the relationship b...Background Several studies have shown that afternoon napping promotes cognitive function in the elderly;on the other hand,some studies have shown opposite results.This current study further examined the relationship between afternoon napping and cognitive function in the ageing Chinese population.Methods A total of 2214 elderly were included(napping group:n=1534;non-napping group:n=680).They all received cognitive evaluations by the Beijing version of the Montreal Cognitive Assessment,the Mini-Mental State Examination,and the Chinese version of the Neuropsychological Test Battery.Among all the subjects,739 elderly volunteered to take blood lipid tests.Results Significant differences in cognitive function and blood lipids were observed between the napping and the non-napping groups.Afternoon napping was associated with better cognitive function including orientation,language,and memory in the present study.Subjects with the habit of afternoon napping also showed a higher level of triglyceride than the non-napping subjects.Conclusion The results demonstrated that afternoon napping was related to better cognitive function in the Chinese ageing population.展开更多
The clinical manifestation of frontal-variant Alzheimer’s disease(fvAD)is not typical,and it is difficult yet necessary to differentiate fvAD from frontal-variant frontal temporal dementia(fvFD).We describe a patient...The clinical manifestation of frontal-variant Alzheimer’s disease(fvAD)is not typical,and it is difficult yet necessary to differentiate fvAD from frontal-variant frontal temporal dementia(fvFD).We describe a patient with early-onset Alzheimer's disease(AD)who presented with an fvFTD-like syndrome and apolipoprotein E ε3/ε4 genotype.A brain amyloid imaging procedure,11 C-Pittsburgh compound B positron emission tomography(PET),supported the final diagnosis of AD.Our present case highlights the clinical variability that characterises early-onset AD.A multimodal approach is crucial when assessing rare forms of dementia.展开更多
The superconducting nanowire single photon detector（SNSPD） draws much attention because of its attractive performance at ultra violet, visible, and nearinfrared wavelengths, and it can be widespread in quantum infor...The superconducting nanowire single photon detector（SNSPD） draws much attention because of its attractive performance at ultra violet, visible, and nearinfrared wavelengths, and it can be widespread in quantum information technologies. However, how to increase the absorption which can dramatically increase the quantum efficiency of the SNSPD is still a top research issue. In this study, the effect of incident medium and cavity material on the optical absorptance of cavity-integrated SNSPDs was systematically investigated using finite-element method. The simulation results demonstrate that for photons polarized parallel to nanowire orientation, even though the maximum absorptance of the nanowire is insensitive to cavity material,it does increase when the refractive index of incident medium decreases. For perpendicularly polarized photons, both incident medium and cavity material play significant roles,and the absorptance curves get closer to the parallel case as the refractive index of cavity material increases. Based on these results, two cavity-integrated SNSPDs with frontillumination structure which can enhance the absorptance for both parallel and perpendicular photons are proposed.Finally, a design to realize polarization-independent SNSPDs with high absorptance is presented.展开更多
Background：Fatty acid（FA） composition is the most important parameter affecting the flavor and nutritional value of the meat.The final and the only committed step in the biosynthesis of triglycerides is catalyzed b...Background：Fatty acid（FA） composition is the most important parameter affecting the flavor and nutritional value of the meat.The final and the only committed step in the biosynthesis of triglycerides is catalyzed by diacylglycerol acyltransferase 2（DGAT2）.The role of DGAT2 in lipid accumulation has been demonstrated in adipocytes,However,little is known about the effect of DGAT2 on the FA composition of these cells.Methods：To investigate the role of DGAT2 in regulating lipid accumulation,FA composition and the expression of adipogenic genes,we cloned the open reading frame of the porcine DGAT2 gene and established 3T3-L1 cells that overexpressed DGAT2.Cells were then cultured in differentiation medium（DM） without FA,with a mixture of FAs（FA-DM）,or containing a ^（13）C stable isotope-labeled FA mixture（IFA-DM）.The FA composition of adipocytes was analyzed by gas chromatography-mass spectrometry and gas chromatography-isotope ratio mass spectrometry.Quantitative PCR and western blotting were employed to detect expression of adipogenic genes in 3T3-L1 adipocytes cultured with FA-DM for 12 d.Results：The triacylglyceride（TAG） content was significantly higher in 3T3-L1 adipocytes overexpressing DGAT2 than in control cells.When cultured in DM or FA-DM for 12 d,cells overexpressing DGAT2 showed a higher proportion of unsaturated FAs（C16：1 and C18：1）.However,when cells overexpressing DGAT2 were cultured with FA-DM for30 min,the FA composition was almost identical to that of controls.Further,the proportion of stable isotope-labeled FAs were similar in 3T3-L1 adipocytes overexpressing DGAT2 and control cells cultured in IFA-DM for 12 d.These results collectively indicate that the higher proportion of mono-unsaturated FAs,C16：1 and C18：1,may originate from de novo FA synthesis but not from the uptake of specific FAs from the medium.This hypothesis is further supported by evidence that both mRNA and protein expression of genes involved in FA synthesis（ACACA,FASN,SCD1,and A-FABP）were significantly higher in cells overexpressing DGAT2 than in control cells.Conclusions：In conclusion,our study revealed that TAG accumulation,the proportion of MUFAs,and the expression of adipogenic genes were higher in 3T3-L1 cells overexpressing DGAT2 than in control cells.展开更多
We report the implementation of qubit-lubit coupling in a three-dimensional （3D） cavity, using the exchange of virtual photons, to realize logical operations. We measure single photon and multi-photon transitions in...We report the implementation of qubit-lubit coupling in a three-dimensional （3D） cavity, using the exchange of virtual photons, to realize logical operations. We measure single photon and multi-photon transitions in this qubit-qubit coupling system and obtain its energy avoided-crossing spectrum. With ac-Stark effect, fast control of the qubits is achieved to tune the effective coupling on and off and the state-swap gate SWAP is successfully constructed. Moreover, using two-photon transition between the ground state and doubly observed. A quarter period of this oscillation corresponds to states, bSWAP and are the foundations of future gate excited states, a kind of two-photon Rabi-like oscillation is the logical gate bSbSWAP, which is used for generating Bell preparation of two-qubit Bell states and realization of CNOT展开更多
In the field of active deorbiting technologies,the electrodynamic tether has garnered attention due to its cost-effectiveness,light weight,and low fuel consumption.In this study,to address the low success rate of the ...In the field of active deorbiting technologies,the electrodynamic tether has garnered attention due to its cost-effectiveness,light weight,and low fuel consumption.In this study,to address the low success rate of the deployment mechanisms used in previous in-orbit experiments,a novel deployment mechanism with a size of 2 U and a weight 2.3 kg based on pusher motors is proposed.In order to achieve a smooth tether deployment without rupture and rebound,an optimization method was proposed for springs,and tether within the deployment mechanism.Finally,simulation and ground ejection experiment were conducted with the objective of deploying a 50-m tether.In the experiment,the top plate was ejected with a kinetic energy of 2.3 J,and the tether was successfully unfolded.The experimental results indicate that the device is capable of deploying a tether of at least 50 m,demonstrating the effectiveness of the optimization method.展开更多
Background:Breast cancer(BC)risk-stratification tools for Asian women that are highly accurate and can provide improved interpretation ability are lacking.We aimed to develop risk-stratification models to predict long...Background:Breast cancer(BC)risk-stratification tools for Asian women that are highly accurate and can provide improved interpretation ability are lacking.We aimed to develop risk-stratification models to predict long-and short-term BC risk among Chinese women and to simultaneously rank potential non-experimental risk factors.Methods:The Breast Cancer Cohort Study in Chinese Women,a large ongoing prospective dynamic cohort study,includes 122,058 women aged 25-70 years old from the eastern part of China.We developed multiple machine-learning risk prediction models using parametric models(penalized logistic regression,bootstrap,and ensemble learning),which were the short-term ensemble penalized logistic regression(EPLR)risk prediction model and the ensemble penalized long-term(EPLT)risk prediction model to estimate BC risk.The models were assessed based on calibration and discrimination,and following this assessment,they were externally validated in new study participants from 2017 to 2020.Results:The AUC values of the short-term EPLR risk prediction model were 0.800 for the internal validation and 0.751 for the external validation set.For the long-term EPLT risk prediction model,the area under the receiver operating characteristic curve was 0.692 and 0.760 in internal and external validations,respectively.The net reclassification improvement index of the EPLT relative to the Gail and the Han Chinese Breast Cancer Prediction Model(HCBCP)models for external validation was 0.193 and 0.233,respectively,indicating that the EPLT model has higher classification accuracy.Conclusions:We developed the EPLR and EPLT models to screen populations with a high risk of developing BC.These can serve as useful tools to aid in risk-stratified screening and BC prevention.展开更多
Spacecraft dynamics and control is essential in several critical space applications, including orbit and attitude mechanics, space robots, deep-space exploration, and space situational awareness. This field is vital f...Spacecraft dynamics and control is essential in several critical space applications, including orbit and attitude mechanics, space robots, deep-space exploration, and space situational awareness. This field is vital for ensuring mission success, safety, and resource efficiency, enabling precise maneuvers for a wide range of scientific, commercial, and interplanetary missions. Effective control systems are crucial for the stability and longevity of spacecraft, contributing to technological advancements and national security. By managing spacecraft movement and orientation, this discipline underpins the success of space exploration and the functionality of satellites, space robots, and probes in various space endeavors.展开更多
Background： Estrogen receptor （ER） and progesterone receptor （PR） are involved in endometriosis, but the involvement of microRNAs （miRNAs） is unknown. The aim of the study was to explore the correlation between...Background： Estrogen receptor （ER） and progesterone receptor （PR） are involved in endometriosis, but the involvement of microRNAs （miRNAs） is unknown. The aim of the study was to explore the correlation between miRNA and EPUPR in uterine tissues of rats with endometriosis during the implantation window. Methods： Twenty female Sprague-Dawley rats were randomized in three groups： endometriosis （n = 7）, fat tissue control （n = 6）, and normal （n = 7） groups. The female rats were mated and sacrificed on day 5 （implantation）. Uterine tissues were obtained for hematoxylin-eosin staining, immunohistochemistry, and miRNA expression. Reverse transcription polymerase chain reaction （RT-PCR） was used to validate the expression of rno-miR-29c-3p, rno-miR-34c-5p, rno-miR-14 l-5p, mo-miR-24-1-5p, and rno-miR-490-5p. Results： The 475 miRNAs were found to differentially express between the endometriosis and normal control groups, with 127 being upregulated and 348 being downregulated. Expression of five miRNAs （rno-miR-29c-3p, rno-miR-34c-5p, rno-miR-141-5p, rno-miR-24-1-5p, and rno-miR-490-5p） were validated by RT-PCR and found to be differentially expressed among the three groups. Expression of ER and PR proteins （immunohistochemistry） in the glandular epithelium and endometrial stroma was significantly different among the three groups （all P 〈 0.05）. Five miRNAs were involved in pathways probably taking part in implantation and fertility. Conclusions： The results suggested that miRNAs, ER, and PR could play important roles in the embryo implantation period of rats with endometriosis. These miRNAs might play a role in endometrial receptivity in endometriosis.展开更多
Embryo implantation in both humans and rodents is initiated by the attachment of a blastocyst to the uterine epithelium.For blastocyst attachment,the uterine epithelium needs to transform at both the structural and mo...Embryo implantation in both humans and rodents is initiated by the attachment of a blastocyst to the uterine epithelium.For blastocyst attachment,the uterine epithelium needs to transform at both the structural and molecular levels first,and then initiate the interaction with trophectoderm.Any perturbation during this process will result in implantation failure or long-term adverse pregnancy outcomes.Endocrine steroid hormones,which function through nuclear receptors,combine with the local molecules produced by the uteri or embryo to facilitate implantation.The insulin-like growth factor(IGF)signaling has been reported to play a vital role during pregnancy.However,its physiological function during implantation remains elusive.This study revealed that mice with conditional deletion of Igflr gene in uteri suffered from subfertility,mainly due to the disturbed uterine receptivity and abnormal embryo implantation.Mechanistically,we uncovered that in response to the nidatory estrogen on D4 of pregnancy,the epithelial IGF1R,stimulated by the stromal cell-produced IGF1,facilitated epithelial STAT3 activation to modulate the epithelial depolarity.Furthermore,embryonic derived IGF2 could activate both the epithelial ERK1/2 and STAT3 signaling through IGF1R,which was critical for the transcription of Cox2 and normal attachment reaction.In brief,our data revealed that epithelial IGF1R was sequentially activated by the uterine stromal IGF1 and embryonic IGF2 to guarantee normal epithelium differentiation during the implantation process.展开更多
Establishment of the primordial follicle(PF)pool is pivotal for the female reproductive lifespan;however,the mechanism of primordial folliculogenesis is poorly understood.Here,the transcription factor SP1 was shown to...Establishment of the primordial follicle(PF)pool is pivotal for the female reproductive lifespan;however,the mechanism of primordial folliculogenesis is poorly understood.Here,the transcription factor SP1 was shown to be essential for PF formation in mice.Our results showed that SP1 is present in both oocytes and somatic cells during PF formation in the ovary.Knockdown of Sp1 expression,especially in pregranulosa cells,significantly suppressed nest breakdown,oocyte apoptosis,and PF formation,suggesting that SP1 expressed by somatic cells functions in the process of primordial folliculogenesis.We further demonstrated that SP1 governs the recruitment and maintenance of Forkhead box L2-positive(FOXL2^+)pregranulosa cells using an Lgr5-EGFP-IRES-CreER^T2(Lgr5-KI)reporter mouse model and a FOXL2^+ cell-specific knockdown model.At the molecular level,SP1 functioned mainly through manipulation of NOTCH2 expression by binding directly to the promoter of the Notch2 gene.Finally,consistent with the critical role of granulosa cells in follicle survival in vitro,massive loss of oocytes in SP1 knockdown ovaries was evidenced before puberty after the ovaries were tranSP1anted under the renal capsules.Conclusively,our results reveal that SP1 controls the establishment of the ovarian reserve by regulating pregranulosa cell development in the mammalian ovary.展开更多
The rapid development of Low Earth Orbit(LEO)mega constellations has significantly contributed to several aspects of human scientific progress,such as communication,navigation,and remote sensing.However,unrestrained d...The rapid development of Low Earth Orbit(LEO)mega constellations has significantly contributed to several aspects of human scientific progress,such as communication,navigation,and remote sensing.However,unrestrained deployment of constellations has also strained orbital resources and increased spacecraft congestion in LEO,which seriously affects the safety of in-orbit operations of many space assets.For the long-term and sustainable development of space activities in LEO regions,space environment stability must be maintained using more rational surveillance and governance mechanisms.This review contributes to the research gap and facilitates the development of LEO mega constellations.First,the current development of typical LEO mega constellations is reviewed,followed by the analysis of the impact of LEO mega constellations in terms of astronomical observation,spacecraft safety in orbit,and space environment evolution.Then,two main solutions to conduct the challenges raised by LEO mage constellations are elaborated:one is to ensure the safety operation of spacecraft using space surveillance infrastructures and space situational awareness technologies,and the other is to accelerate the deorbit of constellation satellites at the end of life based on postmission disposal and active removal methods.Finally,the future development and potential research directions of LEO mega constellations are prospected.展开更多
基金funded by the National Natural Science Foundation of China(No.12202049)the Beijing Institute of Technology Research Fund Program for Young Scholars,China.
文摘Tracking multiple space objects using multiple surveillance sensors is a critical approach in many Space Situation Awareness(SSA) applications. In this process, the uncertainties of targets,dynamics, and observations are usually represented by the probability distributions. However, precise characterization of uncertainty becomes challenging due to imperfect knowledge about some key aspects, such as birth targets and sensor detection profiles. To overcome this challenge, this paper proposes a multi-sensor possibility PHD filter based on the theory of outer probability measures. An effective compensation method is introduced to tackle variations in the fields of view of SSA sensors or instances of missed detections, aiming to mitigate the inconsistency in localized information. The proposed method is adapted to centralized and distributed sensor networks, offering effective solutions for multi-sensor multi-target tracking. The major innovation of the proposed method compared with typical methods is the proper description of epistemic uncertainty, which yields more robust performance in the scenarios of lacking some information about the system.The effectiveness of the multi-sensor possibility PHD filter is demonstrated by a comparison with conventional methods in two simulated scenarios.
基金The work was financially supported by the Natural Science Foundation of Jiangsu Province(Nos.BK20200092 and BK20200710).
文摘To develop smart and efficient near-infrared(NIR)organic dyes for photothermal cancer therapy is of great challenge.Herein,a pH-sensitive NIR dye BTN with donor–acceptor–donor scaffold has been synthesized.Two periphery electron-donating dimethylamine groups in BTN can not only promote the intramolecular photoinduced electron transfer(PET),but also bind protons to transform into electron-deficient ammonium cation for enhanced intramolecular charge transfer(ICT)under acidic circumstance.Through enveloping with amphiphilic polymeric 1,2-distearoyl-ras-glycerol-3-phosphatidyl ethanolamine-N-polyethyleneglycol-2000(DSPE-mPEG2000),BTN nanoparticles(NPs)were fabricated with robust NIR absorption covering 600–900 nm,excellent photothermal conversion efficiency(43.2%),and good photostability.Additionally,BTN NPs can selectively target lysosomes.Through tailing intravenous injection into tumor-bearing nude mice,BTN NPs demonstrate outstanding photoacoustic/photothermal/fluorescence imaging-guided photothermal therapy for tumor ablation.
基金supported by the National Key Research and Development Program of China (2022YFF1001500)the Open Competition Project of Seed Industry Revitalization of Jiangsu Province (JBGS[2021]060)+3 种基金the Core Technology Development for Breeding Program of Jiangsu Province (JBGS-2021-014)China Agriculture Research System of MOF and MARA (CARS-04)the Jiangsu Collaborative Innovation Center for Modern Crop Production (JCIC-MCP)Collaborative Innovation Center for Modern Crop Production Co-sponsored by Province and Ministry (CIC-MCP)。
文摘Drought-induced protein 19(Di19) is a Cys2/His2 zinc-finger protein that functions in plant growth and development and in tolerance to abiotic stresses.Gm PUB21,an E3 ubiquitin ligase,negatively regulates drought and salinity response in soybean.We identified potential interaction target proteins of Gm PUB21by yeast two-hybrid c DNA library screening,Gm Di19-5 as a candidate.Bimolecular fluorescence complementation and glutathionine-S-transferase pull-down assays confirmed the interaction between Gm Di19-5 and Gm PUB21.Gm Di19-5 was induced by Na Cl,drought,and abscisic acid(ABA) treatments.Gm Di19-5 was expressed in the cytoplasm and nucleus.Gm Di19-5 overexpression conferred hypersensitivity to drought and high salinity,whereas Gm Di19-5 silencing increased drought and salinity tolerance.Transcripts of ABA-and stress response-associated genes including Gm RAB18 and Gm DREB2A were downregulated in Gm Di19-5-overexpressing plants under drought and salinity stresses.ABA decreased the protein level of Gm Di19-5 in vivo,whereas Gm PUB21 increased the decrease of Gm Di19-5 after exogenous ABA application.The accumulation of Gm PUB21 was also inhibited by Gm Di19-5.We conclude that Gm PUB21 and Gm Di19-5 collaborate to regulate drought and salinity tolerance via an ABA-dependent pathway.
基金supported by the National Key Research and Development Program of China (No. 2021YFB2011800)Consultation and Evaluation Project of the Faculty of the Chinese Academy of Sciences (No. 2020-HX02-B-030)。
基金This study was funded by grants from the clinical research center project of Shanghai Mental Health Center(CRC2017ZD02)Western medical guidance project of Shanghai Science and Technology Commission(17411970100)+1 种基金National Natural Science Foundation of China(81301139)Precision medical research project of Shanghai Jiao Tong University School of Medicine(15ZH4010).
文摘Background Several studies have shown that afternoon napping promotes cognitive function in the elderly;on the other hand,some studies have shown opposite results.This current study further examined the relationship between afternoon napping and cognitive function in the ageing Chinese population.Methods A total of 2214 elderly were included(napping group:n=1534;non-napping group:n=680).They all received cognitive evaluations by the Beijing version of the Montreal Cognitive Assessment,the Mini-Mental State Examination,and the Chinese version of the Neuropsychological Test Battery.Among all the subjects,739 elderly volunteered to take blood lipid tests.Results Significant differences in cognitive function and blood lipids were observed between the napping and the non-napping groups.Afternoon napping was associated with better cognitive function including orientation,language,and memory in the present study.Subjects with the habit of afternoon napping also showed a higher level of triglyceride than the non-napping subjects.Conclusion The results demonstrated that afternoon napping was related to better cognitive function in the Chinese ageing population.
基金This study was supported by a grant of Clinical Research Center Project of Shanghai Mental Health Center(CRC2017ZD02)Natural Science Foundation of China(81301139)Western medical guidance project of Shanghai science and Technology Commission(17411970100).
文摘The clinical manifestation of frontal-variant Alzheimer’s disease(fvAD)is not typical,and it is difficult yet necessary to differentiate fvAD from frontal-variant frontal temporal dementia(fvFD).We describe a patient with early-onset Alzheimer's disease(AD)who presented with an fvFTD-like syndrome and apolipoprotein E ε3/ε4 genotype.A brain amyloid imaging procedure,11 C-Pittsburgh compound B positron emission tomography(PET),supported the final diagnosis of AD.Our present case highlights the clinical variability that characterises early-onset AD.A multimodal approach is crucial when assessing rare forms of dementia.
基金financially supported by the China State Key Program for Basic Research (No. 2011CBA00304)Tsinghua University Initiative Scientific Research Program (No. 2010Z01010)the National Natural Science Foundation of China (Nos. 61106121 and 61174084)
文摘The superconducting nanowire single photon detector（SNSPD） draws much attention because of its attractive performance at ultra violet, visible, and nearinfrared wavelengths, and it can be widespread in quantum information technologies. However, how to increase the absorption which can dramatically increase the quantum efficiency of the SNSPD is still a top research issue. In this study, the effect of incident medium and cavity material on the optical absorptance of cavity-integrated SNSPDs was systematically investigated using finite-element method. The simulation results demonstrate that for photons polarized parallel to nanowire orientation, even though the maximum absorptance of the nanowire is insensitive to cavity material,it does increase when the refractive index of incident medium decreases. For perpendicularly polarized photons, both incident medium and cavity material play significant roles,and the absorptance curves get closer to the parallel case as the refractive index of cavity material increases. Based on these results, two cavity-integrated SNSPDs with frontillumination structure which can enhance the absorptance for both parallel and perpendicular photons are proposed.Finally, a design to realize polarization-independent SNSPDs with high absorptance is presented.
基金supported by grants from the National Basic Research Program of China-the 973 Program(2012CB1247012013CB127306)+2 种基金the Talent Project of guangdong collegesthe Natural Science Foundation of Guangdong Province of China(S2012020011048)the Research Fund for the Doctoral Program of Higher Education
文摘Background：Fatty acid（FA） composition is the most important parameter affecting the flavor and nutritional value of the meat.The final and the only committed step in the biosynthesis of triglycerides is catalyzed by diacylglycerol acyltransferase 2（DGAT2）.The role of DGAT2 in lipid accumulation has been demonstrated in adipocytes,However,little is known about the effect of DGAT2 on the FA composition of these cells.Methods：To investigate the role of DGAT2 in regulating lipid accumulation,FA composition and the expression of adipogenic genes,we cloned the open reading frame of the porcine DGAT2 gene and established 3T3-L1 cells that overexpressed DGAT2.Cells were then cultured in differentiation medium（DM） without FA,with a mixture of FAs（FA-DM）,or containing a ^（13）C stable isotope-labeled FA mixture（IFA-DM）.The FA composition of adipocytes was analyzed by gas chromatography-mass spectrometry and gas chromatography-isotope ratio mass spectrometry.Quantitative PCR and western blotting were employed to detect expression of adipogenic genes in 3T3-L1 adipocytes cultured with FA-DM for 12 d.Results：The triacylglyceride（TAG） content was significantly higher in 3T3-L1 adipocytes overexpressing DGAT2 than in control cells.When cultured in DM or FA-DM for 12 d,cells overexpressing DGAT2 showed a higher proportion of unsaturated FAs（C16：1 and C18：1）.However,when cells overexpressing DGAT2 were cultured with FA-DM for30 min,the FA composition was almost identical to that of controls.Further,the proportion of stable isotope-labeled FAs were similar in 3T3-L1 adipocytes overexpressing DGAT2 and control cells cultured in IFA-DM for 12 d.These results collectively indicate that the higher proportion of mono-unsaturated FAs,C16：1 and C18：1,may originate from de novo FA synthesis but not from the uptake of specific FAs from the medium.This hypothesis is further supported by evidence that both mRNA and protein expression of genes involved in FA synthesis（ACACA,FASN,SCD1,and A-FABP）were significantly higher in cells overexpressing DGAT2 than in control cells.Conclusions：In conclusion,our study revealed that TAG accumulation,the proportion of MUFAs,and the expression of adipogenic genes were higher in 3T3-L1 cells overexpressing DGAT2 than in control cells.
基金Project supported by the National Basic Research and Development Program of China(Grant No.2011CBA00304)the National Natural Science Foundation of China(Grant Nos.60836001 and 61174084)the Tsinghua University Initiative Scientific Research Program,China(Grant No.20131089314)
文摘We report the implementation of qubit-lubit coupling in a three-dimensional （3D） cavity, using the exchange of virtual photons, to realize logical operations. We measure single photon and multi-photon transitions in this qubit-qubit coupling system and obtain its energy avoided-crossing spectrum. With ac-Stark effect, fast control of the qubits is achieved to tune the effective coupling on and off and the state-swap gate SWAP is successfully constructed. Moreover, using two-photon transition between the ground state and doubly observed. A quarter period of this oscillation corresponds to states, bSWAP and are the foundations of future gate excited states, a kind of two-photon Rabi-like oscillation is the logical gate bSbSWAP, which is used for generating Bell preparation of two-qubit Bell states and realization of CNOT
基金supported by the State Administration of Science,Technology and Industry for National Defense KJSP202360201.
文摘In the field of active deorbiting technologies,the electrodynamic tether has garnered attention due to its cost-effectiveness,light weight,and low fuel consumption.In this study,to address the low success rate of the deployment mechanisms used in previous in-orbit experiments,a novel deployment mechanism with a size of 2 U and a weight 2.3 kg based on pusher motors is proposed.In order to achieve a smooth tether deployment without rupture and rebound,an optimization method was proposed for springs,and tether within the deployment mechanism.Finally,simulation and ground ejection experiment were conducted with the objective of deploying a 50-m tether.In the experiment,the top plate was ejected with a kinetic energy of 2.3 J,and the tether was successfully unfolded.The experimental results indicate that the device is capable of deploying a tether of at least 50 m,demonstrating the effectiveness of the optimization method.
基金supported by grants from China Postdoctoral Science Foundation(Nos.2021M691911,2021M701997)the National Key Research and Development Program of China(No.2016YFC0901301)+1 种基金the Minister-affiliated Hospital Key Project of the Ministry of Health of China(No.07090122)General Programs of Natural Science Foundation of Shandong Province(No.ZR2021MH243).
文摘Background:Breast cancer(BC)risk-stratification tools for Asian women that are highly accurate and can provide improved interpretation ability are lacking.We aimed to develop risk-stratification models to predict long-and short-term BC risk among Chinese women and to simultaneously rank potential non-experimental risk factors.Methods:The Breast Cancer Cohort Study in Chinese Women,a large ongoing prospective dynamic cohort study,includes 122,058 women aged 25-70 years old from the eastern part of China.We developed multiple machine-learning risk prediction models using parametric models(penalized logistic regression,bootstrap,and ensemble learning),which were the short-term ensemble penalized logistic regression(EPLR)risk prediction model and the ensemble penalized long-term(EPLT)risk prediction model to estimate BC risk.The models were assessed based on calibration and discrimination,and following this assessment,they were externally validated in new study participants from 2017 to 2020.Results:The AUC values of the short-term EPLR risk prediction model were 0.800 for the internal validation and 0.751 for the external validation set.For the long-term EPLT risk prediction model,the area under the receiver operating characteristic curve was 0.692 and 0.760 in internal and external validations,respectively.The net reclassification improvement index of the EPLT relative to the Gail and the Han Chinese Breast Cancer Prediction Model(HCBCP)models for external validation was 0.193 and 0.233,respectively,indicating that the EPLT model has higher classification accuracy.Conclusions:We developed the EPLR and EPLT models to screen populations with a high risk of developing BC.These can serve as useful tools to aid in risk-stratified screening and BC prevention.
文摘Spacecraft dynamics and control is essential in several critical space applications, including orbit and attitude mechanics, space robots, deep-space exploration, and space situational awareness. This field is vital for ensuring mission success, safety, and resource efficiency, enabling precise maneuvers for a wide range of scientific, commercial, and interplanetary missions. Effective control systems are crucial for the stability and longevity of spacecraft, contributing to technological advancements and national security. By managing spacecraft movement and orientation, this discipline underpins the success of space exploration and the functionality of satellites, space robots, and probes in various space endeavors.
文摘Background： Estrogen receptor （ER） and progesterone receptor （PR） are involved in endometriosis, but the involvement of microRNAs （miRNAs） is unknown. The aim of the study was to explore the correlation between miRNA and EPUPR in uterine tissues of rats with endometriosis during the implantation window. Methods： Twenty female Sprague-Dawley rats were randomized in three groups： endometriosis （n = 7）, fat tissue control （n = 6）, and normal （n = 7） groups. The female rats were mated and sacrificed on day 5 （implantation）. Uterine tissues were obtained for hematoxylin-eosin staining, immunohistochemistry, and miRNA expression. Reverse transcription polymerase chain reaction （RT-PCR） was used to validate the expression of rno-miR-29c-3p, rno-miR-34c-5p, rno-miR-14 l-5p, mo-miR-24-1-5p, and rno-miR-490-5p. Results： The 475 miRNAs were found to differentially express between the endometriosis and normal control groups, with 127 being upregulated and 348 being downregulated. Expression of five miRNAs （rno-miR-29c-3p, rno-miR-34c-5p, rno-miR-141-5p, rno-miR-24-1-5p, and rno-miR-490-5p） were validated by RT-PCR and found to be differentially expressed among the three groups. Expression of ER and PR proteins （immunohistochemistry） in the glandular epithelium and endometrial stroma was significantly different among the three groups （all P 〈 0.05）. Five miRNAs were involved in pathways probably taking part in implantation and fertility. Conclusions： The results suggested that miRNAs, ER, and PR could play important roles in the embryo implantation period of rats with endometriosis. These miRNAs might play a role in endometrial receptivity in endometriosis.
基金supported by the National Key R&D Program of China(2017YFC1001402 to H.W.2018YFC1004401 to S.K.)+1 种基金the National Natural Science Foundation of China(81830045 and 82030040 to H.W.,81971388 to S.K.)Institution of Higher Education Projects of Building First-class Discipline Construction in Ningxia Region(NXYLXK2017B05 to G.X.).
文摘Embryo implantation in both humans and rodents is initiated by the attachment of a blastocyst to the uterine epithelium.For blastocyst attachment,the uterine epithelium needs to transform at both the structural and molecular levels first,and then initiate the interaction with trophectoderm.Any perturbation during this process will result in implantation failure or long-term adverse pregnancy outcomes.Endocrine steroid hormones,which function through nuclear receptors,combine with the local molecules produced by the uteri or embryo to facilitate implantation.The insulin-like growth factor(IGF)signaling has been reported to play a vital role during pregnancy.However,its physiological function during implantation remains elusive.This study revealed that mice with conditional deletion of Igflr gene in uteri suffered from subfertility,mainly due to the disturbed uterine receptivity and abnormal embryo implantation.Mechanistically,we uncovered that in response to the nidatory estrogen on D4 of pregnancy,the epithelial IGF1R,stimulated by the stromal cell-produced IGF1,facilitated epithelial STAT3 activation to modulate the epithelial depolarity.Furthermore,embryonic derived IGF2 could activate both the epithelial ERK1/2 and STAT3 signaling through IGF1R,which was critical for the transcription of Cox2 and normal attachment reaction.In brief,our data revealed that epithelial IGF1R was sequentially activated by the uterine stromal IGF1 and embryonic IGF2 to guarantee normal epithelium differentiation during the implantation process.
基金supported by grants from the National Key R&D Program of China(2018YFC1003700,2018YFC1003800,and 2017YFC1001100)the National Natural Science Foundation of China(31872792,31371448,and 31571540)+2 种基金Beijing Natural Science Foundation(5182015 and 7182090)Project of State Key Laboratory of Agrobiotechnology(2015SKLAB4-1 and 2016SKLAB-1)Institution of Higher Education Projects of Building First-class Discipline Construction in Ningxia Region(NXYLXK2017B05).
文摘Establishment of the primordial follicle(PF)pool is pivotal for the female reproductive lifespan;however,the mechanism of primordial folliculogenesis is poorly understood.Here,the transcription factor SP1 was shown to be essential for PF formation in mice.Our results showed that SP1 is present in both oocytes and somatic cells during PF formation in the ovary.Knockdown of Sp1 expression,especially in pregranulosa cells,significantly suppressed nest breakdown,oocyte apoptosis,and PF formation,suggesting that SP1 expressed by somatic cells functions in the process of primordial folliculogenesis.We further demonstrated that SP1 governs the recruitment and maintenance of Forkhead box L2-positive(FOXL2^+)pregranulosa cells using an Lgr5-EGFP-IRES-CreER^T2(Lgr5-KI)reporter mouse model and a FOXL2^+ cell-specific knockdown model.At the molecular level,SP1 functioned mainly through manipulation of NOTCH2 expression by binding directly to the promoter of the Notch2 gene.Finally,consistent with the critical role of granulosa cells in follicle survival in vitro,massive loss of oocytes in SP1 knockdown ovaries was evidenced before puberty after the ovaries were tranSP1anted under the renal capsules.Conclusively,our results reveal that SP1 controls the establishment of the ovarian reserve by regulating pregranulosa cell development in the mammalian ovary.
基金supported by the National Natural Science Foundation of China,Outstanding Youth Science Fund Project(11825201).
文摘The rapid development of Low Earth Orbit(LEO)mega constellations has significantly contributed to several aspects of human scientific progress,such as communication,navigation,and remote sensing.However,unrestrained deployment of constellations has also strained orbital resources and increased spacecraft congestion in LEO,which seriously affects the safety of in-orbit operations of many space assets.For the long-term and sustainable development of space activities in LEO regions,space environment stability must be maintained using more rational surveillance and governance mechanisms.This review contributes to the research gap and facilitates the development of LEO mega constellations.First,the current development of typical LEO mega constellations is reviewed,followed by the analysis of the impact of LEO mega constellations in terms of astronomical observation,spacecraft safety in orbit,and space environment evolution.Then,two main solutions to conduct the challenges raised by LEO mage constellations are elaborated:one is to ensure the safety operation of spacecraft using space surveillance infrastructures and space situational awareness technologies,and the other is to accelerate the deorbit of constellation satellites at the end of life based on postmission disposal and active removal methods.Finally,the future development and potential research directions of LEO mega constellations are prospected.
