Improved radio-frequency(RF)power performance of InAlN/GaN high electron mobility transistor(HEMT)is achieved by optimizing the rapid thermal annealing(RTA)process for high-performance low-voltage terminal application...Improved radio-frequency(RF)power performance of InAlN/GaN high electron mobility transistor(HEMT)is achieved by optimizing the rapid thermal annealing(RTA)process for high-performance low-voltage terminal applications.By optimizing the RTA temperature and time,the optimal annealing condition is found to enable low parasitic resistance and thus a high-performance device.Besides,compared with the non-optimized RTA HEMT,the optimized one demonstrates smoother ohmic metal surface morphology and better heterojunction quality including the less degraded heterojunction sheet resistance and clearer heterojunction interfaces as well as negligible material out-diffusion from the barrier to the channel and buffer.Benefiting from the lowered parasitic resistance,improved maximum output current density of 2279 mA·mm^(-1)and higher peak extrinsic transconductance of 526 mS·mm^(-1)are obtained for the optimized RTA HEMT.In addition,due to the superior heterojunction quality,the optimized HEMT shows reduced off-state leakage current of 7×10^(-3)mA·mm^(-1)and suppressed current collapse of only 4%,compared with those of 1×10^(-1)mA·mm^(-1)and 15%for the non-optimized one.At 8 GHz and V_(DS)of 6 V,a significantly improved power-added efficiency of 62%and output power density of 0.71 W·mm^(-1)are achieved for the optimized HEMT,as the result of the improvement in output current,knee voltage,off-state leakage current,and current collapse,which reveals the tremendous advantage of the optimized RTA HEMT in high-performance low-voltage terminal applications.展开更多
Background:China's coastal wetlands belong to some of the most threatened ecosystems worldwide.The loss and degradation of these wetlands seriously threaten waterbirds that depend on wetlands.Methods:The China Coa...Background:China's coastal wetlands belong to some of the most threatened ecosystems worldwide.The loss and degradation of these wetlands seriously threaten waterbirds that depend on wetlands.Methods:The China Coastal Waterbird Census was organized by volunteer birdwatchers in China's coastal region.Waterbirds were surveyed synchronously once every month at 14 sites,as well as irregularly at a further 18 sites,between September 2005 and December 2013.Results:A total of 75 species of waterbirds met the 1 % population level Ramsar listing criterion at least once at one site.The number of birds of the following species accounted for over 20 % of the total flyway populations at a single site:Mute Swan(Cygnus olor),Siberia Crane(Grus leucogeranus),Far Eastern Oystercatcher(Haematopus osculans),Bar-tailed Godwit(Limosa lapponica),Spotted Greenshank(Tringa guttifer),Great Knot(Calidris tenuirostris),Spoon-billed Sandpiper(Calidris pygmeus),Saunders' s Gull(Larus saundersi),Relict Gull(Larus relictus),Great Cormorant(Phalacrocorax carbo),Eurasian Spoonbill(Platalea leucorodia),Black-faced Spoonbill(Platalea minor) and Dalmatian Pelican(Pelecanus crispus).A total of 26 sites supported at least one species of which their number met the1 % criterion.Forty-two species met the 1 % criterion in the Yellow River Delta,Shandong;29 at the Cangzhou coast,Hebei and 26 species at the Lianyungang coast,Jiangsu.Conclusions:The results highlight the international importance of China's coastal wetlands for waterbirds.This study also demonstrates that participation of local birdwatchers in waterbird surveys results in data that are invaluable not only for understanding the current status of waterbirds in China's coastal regions but also for waterbird conservation and management.展开更多
We examined a total of 16 children with epileptic encephalopathy using fluo-rine-18-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission computed tomography (PET), magnetic resonance imaging (MRI) and electroencephalo...We examined a total of 16 children with epileptic encephalopathy using fluo-rine-18-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission computed tomography (PET), magnetic resonance imaging (MRI) and electroencephalography. Children with infantile spasms showed significant mental retardation, severely abnormal electroencephalogram recordings, and bilateral diffuse cerebral cortex hypometabolism with 18F-FDG PET imaging. MRI in these cases showed brain atrophy, multi-micropolygyria, macrogyria, and porencephalia. In cases with Len-nox-Gastaut syndrome, 18F-FDG PET showed bilateral diffuse glucose hypometabolism, while MRI showed cortical atrophy, heterotopic gray matter and tuberous sclerosis. MRI in cases with myoclonic encephalopathy demonstrated bilateral frontal and temporal cortical and white matter atrophy and 18F-FDG PET imaging showed bilateral frontal lobe atrophy with reduced bilateral frontal cortex, occipital cortex, temporal cortex and cerebellar glucose uptake. In children who could not be clearly classified, MRI demonstrated cerebral cortical atrophy and 18F-FDG PET exhibited multifocal glucose hypometabolism. Overall, this study demonstrated that the degree of brain metabolic abnormality was consistent with clinical seizure severity. In addition, 18F-FDG PET imaging after treatment was consistent with clinical outcomes. These findings indicate that 18F-FDG PET can be used to assess the severity of brain injury and prognosis in children with epileptic encephalopathy.展开更多
In the present study, a rat model of type 2 diabetes mellitus was established by continuous peritoneal injection of streptozotocin. Following intragastric perfusion of sericin for 35 days, blood glucose levels signifi...In the present study, a rat model of type 2 diabetes mellitus was established by continuous peritoneal injection of streptozotocin. Following intragastric perfusion of sericin for 35 days, blood glucose levels significantly reduced, neuronal apoptosis in the hippocampal CA1 region decreased, hippocampal phosphorylated Akt and nuclear factor kappa B expression were enhanced, but Bcl-xL/Bcl-2 associated death promoter expression decreased. Results demonstrated that sericin can reduce hippocampal neuronal apoptosis in a rat model of diabetes mellitus by regulating abnormal changes in the Akt signal transduction pathway.展开更多
With the development of EMC technology, EMC assessment has become increasingly important in EMC design. Although numerous EMC assessment models are available today, few of them can provide a tradeoff between efficienc...With the development of EMC technology, EMC assessment has become increasingly important in EMC design. Although numerous EMC assessment models are available today, few of them can provide a tradeoff between efficiency and accuracy for the specific case of military vehicular communication systems. Face to this situation, a modified four-level assessment model is proposed in the paper. First, the development of EMC assessment technology is briefly reviewed, and the theoretical mechanism of EMI environment is introduced. Then, the architecture of the proposed model is outlined, and the assessment methods are explored. To demonstrate the application of it, an example involving a communication system in a military vehicle is presented. From the physical layer to the signal layer, a hierarchical assessment on the entire system is successfully performed based on the proposed model, and we can make a qualitative EMC assessment on the EMC performance of the system. Based on a comparison with the traditional model, we conclude that the proposed model is more accurate, more efficient and less time-consuming, which is suitable for the EMC assessment on militaryvehicular communication systems. We hope that the proposed model will serve as a useful reference for system-level EMC assessments for other systems.展开更多
Sericin from discarded silkworm cocoons of silk reeling has been used in different fields,such as cosmetology,skin care,nutrition,and oncology.The present study established a rat model of type 2 diabetes by consecutiv...Sericin from discarded silkworm cocoons of silk reeling has been used in different fields,such as cosmetology,skin care,nutrition,and oncology.The present study established a rat model of type 2 diabetes by consecutive intraperitoneal injections of low-dose (25 mg/kg) streptozotocin.After intragastrical perfusion of sericin for 35 days,blood glucose levels significantly declined,and the expression of neurofilament protein in the sciatic nerve and nerve growth factor in L4-6 spinal ganglion and anterior horn cells significantly increased.However,the expression of neuropeptide Y in spinal ganglion and anterior horn cells significantly decreased in model rats.These findings indicate that sericin protected the sciatic nerve and related nerve cells against injury in a rat type 2 diabetic model by upregulating the expression of neurofilament protein in the sciatic nerve and nerve growth factor in spinal ganglion and anterior horn cells,and downregulating the expression of neuropeptide Y in spinal ganglion and anterior horn cells.展开更多
Previous studies have shown that sericin extracted from silk cocoon significantly reduces blood glucose levels and protects the nervous system against diabetes mellitus. In this study, a rat type 2 diabetes mellitus m...Previous studies have shown that sericin extracted from silk cocoon significantly reduces blood glucose levels and protects the nervous system against diabetes mellitus. In this study, a rat type 2 diabetes mellitus model was established by intraperitoneal injection of 25 mg/kg streptozotocin for 3 successive days, following which the rats were treated with sericin for 35 days. After treatment, the blood glucose levels of the diabetic rats decreased significantly, the growth hormone level in serum and its expression in the hippocampus decreased significantly, while the insulin-like growth factor-1 level in serum and insulin-like growth factor-1 and growth hormone receptor expression in the hippocampus increased significantly. The experimental findings indicate that sericin improves disorders of the growth hormone/insulin-like growth factor 1 axis to alleviate hippocampal damage in diabetic rats.展开更多
We observed dynamic changes in microvessels and a protective effect of estrogen on chronic cerebral ischemia ovariectomized rat models established through permanent occlusion of bilateral carotid arteries at 7,14 and ...We observed dynamic changes in microvessels and a protective effect of estrogen on chronic cerebral ischemia ovariectomized rat models established through permanent occlusion of bilateral carotid arteries at 7,14 and 21 days.The results revealed that estrogen improved microvasculature in the hippocampus of chronic cerebral ischemic rats,upregulated Bcl-2 protein expression,downregulated Bax protein expression,increased choline acetyltransferase expression in hippocampal cholinergic neurons,and suppressed hippocampal neuronal apoptosis.These findings indicate that estrogen can protect hippocampal neurons in rats with chronic cerebral ischemia.展开更多
We demonstrate a novel Si-rich SiN bilayer passivation technology for AlGaN/GaN high electron mobility transistors(HEMTs)with thin-barrier to minimize surface leakage current to enhance the breakdown voltage.The bilay...We demonstrate a novel Si-rich SiN bilayer passivation technology for AlGaN/GaN high electron mobility transistors(HEMTs)with thin-barrier to minimize surface leakage current to enhance the breakdown voltage.The bilayer SiN with 20-nm Si-rich SiN and 100-nm Si_(3)N_(4) was deposited by plasma-enhanced chemical vapor deposition(PECVD)after removing 20-nm SiO_(2)pre-deposition layer.Compared to traditional Si_(3)N_(4) passivation for thin-barrier AlGaN/GaN HEMTs,Si-rich SiN bilayer passivation can suppress the current collapse ratio from 18.54%to 8.40%.However,Si-rich bilayer passivation leads to a severer surface leakage current,so that it has a low breakdown voltage.The 20-nm SiO_(2)pre-deposition layer can protect the surface of HEMTs in fabrication process and decrease Ga–O bonds,resulting in a lower surface leakage current.In contrast to passivating Si-rich SiN directly,devices with the novel Si-rich SiN bilayer passivation increase the breakdown voltage from 29 V to 85 V.Radio frequency(RF)small-signal characteristics show that HEMTs with the novel bilayer SiN passivation leads to f_(T)/f_(max) of 68 GHz/102 GHz.At 30 GHz and V_(DS)=20 V,devices achieve a maximum P_(out) of 5.2 W/mm and a peak power-added efficiency(PAE)of 42.2%.These results indicate that HEMTs with the novel bilayer SiN passivation can have potential applications in the millimeter-wave range.展开更多
Objective: To investigate whether laminin 5 (LN5) might be a predictor in lung cancer patient treated with gefitinib and estimate the underlying mechanisms. Methods: LN5 and epidermal growth factor receptor (EGFR) mRN...Objective: To investigate whether laminin 5 (LN5) might be a predictor in lung cancer patient treated with gefitinib and estimate the underlying mechanisms. Methods: LN5 and epidermal growth factor receptor (EGFR) mRNA expression level were detected in the tumor tissues of lung cancer patients who underwent surgery resection prior to gefitinib treatment. EGFR exon 19 and 21 mutation status was also detected in these specimens. The association between LN5, EGFR mRNA expression level, EGFR mutation and gefitinib treatment response were evaluated. In vitro study were carried by adding exog- enous LN5 and gefitinib to A549 lung cancer cell line, and Western-blotting was performed to investigate the phosphorylation level of EGFR,Ak, and Erk. Results: The disease control rate according to LN5 mRNA level was 52.9% for the below cut- point group, and 17.6% for the above cut-point (P = 0.009). The in vitro study showed that exogenous LN5 can neutralize the inhibition of phosphor-Akt by gefitinib. Conclusion: Patients with lower LN5 mRNA level would likely benefit from gefitinib. In vitro study indicated that the inhibition of Akt induced by gefitinib might be reversed by LN5. These results provide important insights into the molecular mechanisms underlying sensitivity to gefitinib in lung cancer patients.展开更多
Image Aesthetic Assessment (IAA) is a widely considered problem given its usefulness in a wide range of applications such as the evaluation image capture pipelines, sharing and storage techniques media, but the intrin...Image Aesthetic Assessment (IAA) is a widely considered problem given its usefulness in a wide range of applications such as the evaluation image capture pipelines, sharing and storage techniques media, but the intrinsic mechanism of aesthetic evaluation is seldom been explored due to its subjective nature and the lack of interpretability of deep neural networks. Noticing that the photographic style annotations of images (<em>i</em>.<em>e</em>. the score of aesthetic attributes) are more objective and interpretable compared with the Mean Opinion Scores (MOS) annotations for IAA, we evaluate the problem of Aesthetic Attributes Assessment (AAA) as to provide complementary information for IAA. We firstly introduce the learning of data covariance in the field of Aesthetic Attributes Assessment and propose a regression model that jointly learns from MOS as well as the score of all aesthetic attributes at the same time. We construct our method by extending the scheme of data uncertainty learning and propose data covariance learning. Our method achieves the state-of-the-art performance on AAA without architectural design that trains in a totally end-to-end manner and can be easily extended to existing IAA methods.展开更多
A novel benzene-ring engineered 1D/2D WO_(3)/g-C_(3)N_(4)S-scheme photocatalyst(BCNW)was rationally de-signed and successfully synthesized by the electrostatic self-assembly method.Experimental and Density Functional ...A novel benzene-ring engineered 1D/2D WO_(3)/g-C_(3)N_(4)S-scheme photocatalyst(BCNW)was rationally de-signed and successfully synthesized by the electrostatic self-assembly method.Experimental and Density Functional Theory results reveal that the integration of molecular benzene-ring in the framework of g-C_(3)N_(4)can not only narrow its bandgap and accelerate charge separation by forming a mid-state at the top of its valence band but more importantly open up a new additional bridge for speeding up the interfacial S-scheme charge transfer in BCNW.Benefitting from those multiple positive effects of benzene-ring inte-gration,as expected,BCNW S-scheme photocatalysts show superior photocatalytic H_(2)-production activity and reach 2971μmol h^(-1)g^(-1)under visible-light illumination,which is 3.35 times WO_(3)/g-C_(3)N_(4)S-scheme photocatalyst without benzene-ring integration.This work supplies an innovative strategy for the design of a high-efficiency S-scheme photocatalytic system by constructing a facile and additional molecular charge transfer channel at the interface.展开更多
Multiferroics are an intriguing family of materials due to the simultaneous presence of two ferroic orderings,namely,ferroelectricity and ferromagnetism.They are scientifically and technologically important and have n...Multiferroics are an intriguing family of materials due to the simultaneous presence of two ferroic orderings,namely,ferroelectricity and ferromagnetism.They are scientifically and technologically important and have numerous potential applications,such as four-state logic memories and multiferroic tunneling junctions.However,the growth of epitaxial singlephase multiferroic thin films typically requires single crystalline oxide substrates,which hinders their future integration with Sibased devices.In this study,we report a generalized synthesis method that uses the polydimethylsiloxane(PDMS)-assisted wetetching method with an Sr_(3)Al_(2)O_(6)(SAO)sacrificial layer to transfer freestanding single-phase multiferroic Bi_(2)NiMnO_(6)(BNMO)films from conventional SrTiO_(3)(STO)substrates onto a Si wafer.The structures and properties of the films have been characterized before and after the transfer.These transferred films possess good multiferroic properties on Si wafers,indicating full compatibility with modern Si technology.This method can be generally applicable to other Bi-based multiferroic materials as well.Lastly,the original STO substrates after the transfer process have been recycled for preparing new batches of freestanding BNMO films,indicating a low-cost and sustainable method for manufacturing large-volume freestanding complex oxide thin films.展开更多
Non-precious metal electrocatalyst molybdenum sulphide(MoS) and black phosphorus(BP) are highly promising catalysts for H_(2) evolution reaction(HER).However,BP is environmentally unstable and the basal planes of crys...Non-precious metal electrocatalyst molybdenum sulphide(MoS) and black phosphorus(BP) are highly promising catalysts for H_(2) evolution reaction(HER).However,BP is environmentally unstable and the basal planes of crystal MoS_(2) are inactive toward HER.Herein,amorphous molybdenum sulphide(MoSx)directly on BP/BiVO4 film dramatically improves the performance of photoelectrochemical water splitting compared with pure BiVO4.Additionally,we demonstrate that a BP layer,inserted between the MoSx and BiVO4,can enhance the photoelectrochemical performance and improve the stability of the electrodes.Finally,MoS_(x)/B P/BVO electrode shows the excellent current density of 2.1 mA/cm^(2) at the potential of 1.2 V(vs Ag/AgCl),which is twice higher than that of pure BVO electrode.Our novel nanostructure materials will lead to a new class of non-precious metal photocatalysts for hydrogen production.展开更多
It is generally accepted that perpendicular magnetic anisotropy(PMA)magnets are preferred over in-plane magnetic anisotropy(IMA)magnets in data storage applications owing to their large thermal stability even at ultra...It is generally accepted that perpendicular magnetic anisotropy(PMA)magnets are preferred over in-plane magnetic anisotropy(IMA)magnets in data storage applications owing to their large thermal stability even at ultra-scaled dimensions.To efficiently and deterministically switch a PMA,out-of-plan spin current is required.However,conventional giant spin Hall effect(GSHE)materials only produce spin currents with in-plane polarization.Our work,on the other hand,demonstrated for the first time that out-of-plane spin currents can indeed be generated by applying electric filed to monolayer WSe2 at room temperature and the spin information was detected by a graphene channel.Supported by theoretical calculations,we found that the interfacial polarization between graphene and WSe2 to be^38%assuming the ferromagnetic detector's polarization efficiency to be^4%.Moreover,the spin polarization is determined by the polarity of the applied electric field.展开更多
Background:The incidence of new-onset diabetes mellitus(NODM)after distal pancreatectomy(DP)remains high.Few studies have focused on NODM in patients with pancreatic benign or low-grade malignant lesions(PBLML).This s...Background:The incidence of new-onset diabetes mellitus(NODM)after distal pancreatectomy(DP)remains high.Few studies have focused on NODM in patients with pancreatic benign or low-grade malignant lesions(PBLML).This study aimed to develop and validate an effective clinical model for risk prediction and stratification of NODM after DP in patients with PBLML.Methods:A follow-up survey was conducted to investigate NODM in patients without preoperative DM who underwent DP.Four hundred and forty-eight patients from Peking Union Medical College Hospital(PUMCH)and 178 from Guangdong Provincial People’s Hospital(GDPH)met the inclusion criteria.They constituted the training cohort and the validation cohort,respectively.Univariate and multivariate Cox regression,as well as least absolute shrinkage and selection operator(LASSO)analyses,were used to identify the independent risk factors.The nomogram was constructed and verified.Concordance index(C-index),receiver operating characteristic(ROC)curve,calibration curves,and decision curve analysis(DCA)were applied to assess its predictive performance and clinical utility.Accordingly,the optimal cut-off point was determined by maximally selected rank statistics method,and the cumulative risk curves for the high-and low-risk populations were plotted to evaluate the discrimination ability of the nomogram.Results:The median follow-up duration was 42.8 months in the PUMCH cohort and 42.9 months in the GDPH cohort.The postoperative cumulative 5-year incidences of DM were 29.1%and 22.1%,respectively.Age,body mass index(BMI),length of pancreatic resection,intraoperative blood loss,and concomitant splenectomy were significant risk factors.The nomogram demonstrated significant predictive utility for post-pancreatectomy DM.The C-indexes of the nomogram were 0.739 and 0.719 in the training and validation cohorts,respectively.ROC curves demonstrated the predictive accuracy of the nomogram,and the calibration curves revealed that prediction results were in general agreement with the actual results.The considerable clinical applicability of the nomogram was certified by DCA.The optimal cut-off point for Background:The incidence of new-onset diabetes mellitus(NODM)after distal pancreatectomy(DP)remains high.Few studies have focused on NODM in patients with pancreatic benign or low-grade malignant lesions(PBLML).This study aimed to develop and validate an effective clinical model for risk prediction and stratification of NODM after DP in patients with PBLML.Methods:A follow-up survey was conducted to investigate NODM in patients without preoperative DM who underwent DP.Four hundred and forty-eight patients from Peking Union Medical College Hospital(PUMCH)and 178 from Guangdong Provincial People’s Hospital(GDPH)met the inclusion criteria.They constituted the training cohort and the validation cohort,respectively.Univariate and multivariate Cox regression,as well as least absolute shrinkage and selection operator(LASSO)analyses,were used to identify the independent risk factors.The nomogram was constructed and verified.Concordance index(C-index),receiver operating characteristic(ROC)curve,calibration curves,and decision curve analysis(DCA)were applied to assess its predictive performance and clinical utility.Accordingly,the optimal cut-off point was determined by maximally selected rank statistics method,and the cumulative risk curves for the high-and low-risk populations were plotted to evaluate the discrimination ability of the nomogram.Results:The median follow-up duration was 42.8 months in the PUMCH cohort and 42.9 months in the GDPH cohort.The postoperative cumulative 5-year incidences of DM were 29.1%and 22.1%,respectively.Age,body mass index(BMI),length of pancreatic resection,intraoperative blood loss,and concomitant splenectomy were significant risk factors.The nomogram demonstrated significant predictive utility for post-pancreatectomy DM.The C-indexes of the nomogram were 0.739 and 0.719 in the training and validation cohorts,respectively.ROC curves demonstrated the predictive accuracy of the nomogram,and the calibration curves revealed that prediction results were in general agreement with the actual results.The considerable clinical applicability of the nomogram was certified by DCA.The optimal cut-off point for risk prediction value was 2.88, and the cumulative risk curves of each cohort showed significant differences between the high- and low-risk groups. Conclusions: The nomogram could predict and identify the NODM risk population, and provide guidance to physicians in monitoring and controlling blood glucose levels in PBLML patients after DP.展开更多
基金Project supported by the National Key Research and Development Project of China (Grant No.2021YFB3602404)part by the National Natural Science Foundation of China (Grant Nos.61904135 and 62234009)+4 种基金the Key R&D Program of Guangzhou (Grant No.202103020002)Wuhu and Xidian University special fund for industry-university-research cooperation (Grant No.XWYCXY-012021014-HT)the Fundamental Research Funds for the Central Universities (Grant No.XJS221110)the Natural Science Foundation of Shaanxi,China (Grant No.2022JM-377)the Innovation Fund of Xidian University (Grant No.YJSJ23019)。
文摘Improved radio-frequency(RF)power performance of InAlN/GaN high electron mobility transistor(HEMT)is achieved by optimizing the rapid thermal annealing(RTA)process for high-performance low-voltage terminal applications.By optimizing the RTA temperature and time,the optimal annealing condition is found to enable low parasitic resistance and thus a high-performance device.Besides,compared with the non-optimized RTA HEMT,the optimized one demonstrates smoother ohmic metal surface morphology and better heterojunction quality including the less degraded heterojunction sheet resistance and clearer heterojunction interfaces as well as negligible material out-diffusion from the barrier to the channel and buffer.Benefiting from the lowered parasitic resistance,improved maximum output current density of 2279 mA·mm^(-1)and higher peak extrinsic transconductance of 526 mS·mm^(-1)are obtained for the optimized RTA HEMT.In addition,due to the superior heterojunction quality,the optimized HEMT shows reduced off-state leakage current of 7×10^(-3)mA·mm^(-1)and suppressed current collapse of only 4%,compared with those of 1×10^(-1)mA·mm^(-1)and 15%for the non-optimized one.At 8 GHz and V_(DS)of 6 V,a significantly improved power-added efficiency of 62%and output power density of 0.71 W·mm^(-1)are achieved for the optimized HEMT,as the result of the improvement in output current,knee voltage,off-state leakage current,and current collapse,which reveals the tremendous advantage of the optimized RTA HEMT in high-performance low-voltage terminal applications.
文摘Background:China's coastal wetlands belong to some of the most threatened ecosystems worldwide.The loss and degradation of these wetlands seriously threaten waterbirds that depend on wetlands.Methods:The China Coastal Waterbird Census was organized by volunteer birdwatchers in China's coastal region.Waterbirds were surveyed synchronously once every month at 14 sites,as well as irregularly at a further 18 sites,between September 2005 and December 2013.Results:A total of 75 species of waterbirds met the 1 % population level Ramsar listing criterion at least once at one site.The number of birds of the following species accounted for over 20 % of the total flyway populations at a single site:Mute Swan(Cygnus olor),Siberia Crane(Grus leucogeranus),Far Eastern Oystercatcher(Haematopus osculans),Bar-tailed Godwit(Limosa lapponica),Spotted Greenshank(Tringa guttifer),Great Knot(Calidris tenuirostris),Spoon-billed Sandpiper(Calidris pygmeus),Saunders' s Gull(Larus saundersi),Relict Gull(Larus relictus),Great Cormorant(Phalacrocorax carbo),Eurasian Spoonbill(Platalea leucorodia),Black-faced Spoonbill(Platalea minor) and Dalmatian Pelican(Pelecanus crispus).A total of 26 sites supported at least one species of which their number met the1 % criterion.Forty-two species met the 1 % criterion in the Yellow River Delta,Shandong;29 at the Cangzhou coast,Hebei and 26 species at the Lianyungang coast,Jiangsu.Conclusions:The results highlight the international importance of China's coastal wetlands for waterbirds.This study also demonstrates that participation of local birdwatchers in waterbird surveys results in data that are invaluable not only for understanding the current status of waterbirds in China's coastal regions but also for waterbird conservation and management.
基金the National Natural Science Foundation of China, No. 81071046the Guangdong Provincial Science and Technology Program, No. 2009B030801250+1 种基金2010 Guangdong Provincial Science and Technology Program, No. 2010B031600159the Guangdong Province Natural Science Foundation, No. 7001205
文摘We examined a total of 16 children with epileptic encephalopathy using fluo-rine-18-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission computed tomography (PET), magnetic resonance imaging (MRI) and electroencephalography. Children with infantile spasms showed significant mental retardation, severely abnormal electroencephalogram recordings, and bilateral diffuse cerebral cortex hypometabolism with 18F-FDG PET imaging. MRI in these cases showed brain atrophy, multi-micropolygyria, macrogyria, and porencephalia. In cases with Len-nox-Gastaut syndrome, 18F-FDG PET showed bilateral diffuse glucose hypometabolism, while MRI showed cortical atrophy, heterotopic gray matter and tuberous sclerosis. MRI in cases with myoclonic encephalopathy demonstrated bilateral frontal and temporal cortical and white matter atrophy and 18F-FDG PET imaging showed bilateral frontal lobe atrophy with reduced bilateral frontal cortex, occipital cortex, temporal cortex and cerebellar glucose uptake. In children who could not be clearly classified, MRI demonstrated cerebral cortical atrophy and 18F-FDG PET exhibited multifocal glucose hypometabolism. Overall, this study demonstrated that the degree of brain metabolic abnormality was consistent with clinical seizure severity. In addition, 18F-FDG PET imaging after treatment was consistent with clinical outcomes. These findings indicate that 18F-FDG PET can be used to assess the severity of brain injury and prognosis in children with epileptic encephalopathy.
基金supported by a grant from the Education Department of Hebei Province (Mechanism of GH/IGF-1 and protective effects of sericin on gonadal axis lesions in diabetes mellitus), No. 2006301a grant from Science and Technology Department of Hebei Province (Protective effects of sericin on testicular dysfunction in diabetes mellitus), No. 08276101D-19
文摘In the present study, a rat model of type 2 diabetes mellitus was established by continuous peritoneal injection of streptozotocin. Following intragastric perfusion of sericin for 35 days, blood glucose levels significantly reduced, neuronal apoptosis in the hippocampal CA1 region decreased, hippocampal phosphorylated Akt and nuclear factor kappa B expression were enhanced, but Bcl-xL/Bcl-2 associated death promoter expression decreased. Results demonstrated that sericin can reduce hippocampal neuronal apoptosis in a rat model of diabetes mellitus by regulating abnormal changes in the Akt signal transduction pathway.
基金supported by the National Moon Exploration Program of China (No. TY3Q20110020)in part supported by the 13th Five-Year Community Technology Research Program of National Equipment Development Department of China (No.41409020301)the National Natural Science Foundation of China (50971094)
文摘With the development of EMC technology, EMC assessment has become increasingly important in EMC design. Although numerous EMC assessment models are available today, few of them can provide a tradeoff between efficiency and accuracy for the specific case of military vehicular communication systems. Face to this situation, a modified four-level assessment model is proposed in the paper. First, the development of EMC assessment technology is briefly reviewed, and the theoretical mechanism of EMI environment is introduced. Then, the architecture of the proposed model is outlined, and the assessment methods are explored. To demonstrate the application of it, an example involving a communication system in a military vehicle is presented. From the physical layer to the signal layer, a hierarchical assessment on the entire system is successfully performed based on the proposed model, and we can make a qualitative EMC assessment on the EMC performance of the system. Based on a comparison with the traditional model, we conclude that the proposed model is more accurate, more efficient and less time-consuming, which is suitable for the EMC assessment on militaryvehicular communication systems. We hope that the proposed model will serve as a useful reference for system-level EMC assessments for other systems.
文摘Sericin from discarded silkworm cocoons of silk reeling has been used in different fields,such as cosmetology,skin care,nutrition,and oncology.The present study established a rat model of type 2 diabetes by consecutive intraperitoneal injections of low-dose (25 mg/kg) streptozotocin.After intragastrical perfusion of sericin for 35 days,blood glucose levels significantly declined,and the expression of neurofilament protein in the sciatic nerve and nerve growth factor in L4-6 spinal ganglion and anterior horn cells significantly increased.However,the expression of neuropeptide Y in spinal ganglion and anterior horn cells significantly decreased in model rats.These findings indicate that sericin protected the sciatic nerve and related nerve cells against injury in a rat type 2 diabetic model by upregulating the expression of neurofilament protein in the sciatic nerve and nerve growth factor in spinal ganglion and anterior horn cells,and downregulating the expression of neuropeptide Y in spinal ganglion and anterior horn cells.
基金sponsored by the Natural Science Foundation of Hebei Province,H2012406018,H2013406096a grant from Hebei Province Department of Education,No.2006301
文摘Previous studies have shown that sericin extracted from silk cocoon significantly reduces blood glucose levels and protects the nervous system against diabetes mellitus. In this study, a rat type 2 diabetes mellitus model was established by intraperitoneal injection of 25 mg/kg streptozotocin for 3 successive days, following which the rats were treated with sericin for 35 days. After treatment, the blood glucose levels of the diabetic rats decreased significantly, the growth hormone level in serum and its expression in the hippocampus decreased significantly, while the insulin-like growth factor-1 level in serum and insulin-like growth factor-1 and growth hormone receptor expression in the hippocampus increased significantly. The experimental findings indicate that sericin improves disorders of the growth hormone/insulin-like growth factor 1 axis to alleviate hippocampal damage in diabetic rats.
基金a grant by Hebei Provincial Education Ministry,No.Z200632
文摘We observed dynamic changes in microvessels and a protective effect of estrogen on chronic cerebral ischemia ovariectomized rat models established through permanent occlusion of bilateral carotid arteries at 7,14 and 21 days.The results revealed that estrogen improved microvasculature in the hippocampus of chronic cerebral ischemic rats,upregulated Bcl-2 protein expression,downregulated Bax protein expression,increased choline acetyltransferase expression in hippocampal cholinergic neurons,and suppressed hippocampal neuronal apoptosis.These findings indicate that estrogen can protect hippocampal neurons in rats with chronic cerebral ischemia.
基金Project supported by the National Key Research and Development Program of China(Grant No.2020YFB1804902)the National Natural Science Foundation of China(Grant Nos.61904135,62090014,and 11690042)+4 种基金the Fundamental Research Funds for the Central Universities,the Innovation Fund of Xidian University(Grant No.YJS2213)the China Postdoctoral Science Foundation(Grant Nos.2018M640957 and BX20200262)the Key Research and Development Program of Guangzhou(Grant No.202103020002)Wuhu and Xidian University Special Fund for Industry–University-Research Cooperation(Grant No.XWYCXY-012021014HT)the Fundamental Research Funds for the Central Universities,China(Grant No.XJS221110)。
文摘We demonstrate a novel Si-rich SiN bilayer passivation technology for AlGaN/GaN high electron mobility transistors(HEMTs)with thin-barrier to minimize surface leakage current to enhance the breakdown voltage.The bilayer SiN with 20-nm Si-rich SiN and 100-nm Si_(3)N_(4) was deposited by plasma-enhanced chemical vapor deposition(PECVD)after removing 20-nm SiO_(2)pre-deposition layer.Compared to traditional Si_(3)N_(4) passivation for thin-barrier AlGaN/GaN HEMTs,Si-rich SiN bilayer passivation can suppress the current collapse ratio from 18.54%to 8.40%.However,Si-rich bilayer passivation leads to a severer surface leakage current,so that it has a low breakdown voltage.The 20-nm SiO_(2)pre-deposition layer can protect the surface of HEMTs in fabrication process and decrease Ga–O bonds,resulting in a lower surface leakage current.In contrast to passivating Si-rich SiN directly,devices with the novel Si-rich SiN bilayer passivation increase the breakdown voltage from 29 V to 85 V.Radio frequency(RF)small-signal characteristics show that HEMTs with the novel bilayer SiN passivation leads to f_(T)/f_(max) of 68 GHz/102 GHz.At 30 GHz and V_(DS)=20 V,devices achieve a maximum P_(out) of 5.2 W/mm and a peak power-added efficiency(PAE)of 42.2%.These results indicate that HEMTs with the novel bilayer SiN passivation can have potential applications in the millimeter-wave range.
基金Supported by grants from the National Natural Science Foundation of China (No. 30772531)Guangdong Provincial Medical Science and Technology Research Foundation (No. B2006001)China Postdoc toral Science Foundation (No. 20060400212)
文摘Objective: To investigate whether laminin 5 (LN5) might be a predictor in lung cancer patient treated with gefitinib and estimate the underlying mechanisms. Methods: LN5 and epidermal growth factor receptor (EGFR) mRNA expression level were detected in the tumor tissues of lung cancer patients who underwent surgery resection prior to gefitinib treatment. EGFR exon 19 and 21 mutation status was also detected in these specimens. The association between LN5, EGFR mRNA expression level, EGFR mutation and gefitinib treatment response were evaluated. In vitro study were carried by adding exog- enous LN5 and gefitinib to A549 lung cancer cell line, and Western-blotting was performed to investigate the phosphorylation level of EGFR,Ak, and Erk. Results: The disease control rate according to LN5 mRNA level was 52.9% for the below cut- point group, and 17.6% for the above cut-point (P = 0.009). The in vitro study showed that exogenous LN5 can neutralize the inhibition of phosphor-Akt by gefitinib. Conclusion: Patients with lower LN5 mRNA level would likely benefit from gefitinib. In vitro study indicated that the inhibition of Akt induced by gefitinib might be reversed by LN5. These results provide important insights into the molecular mechanisms underlying sensitivity to gefitinib in lung cancer patients.
文摘Image Aesthetic Assessment (IAA) is a widely considered problem given its usefulness in a wide range of applications such as the evaluation image capture pipelines, sharing and storage techniques media, but the intrinsic mechanism of aesthetic evaluation is seldom been explored due to its subjective nature and the lack of interpretability of deep neural networks. Noticing that the photographic style annotations of images (<em>i</em>.<em>e</em>. the score of aesthetic attributes) are more objective and interpretable compared with the Mean Opinion Scores (MOS) annotations for IAA, we evaluate the problem of Aesthetic Attributes Assessment (AAA) as to provide complementary information for IAA. We firstly introduce the learning of data covariance in the field of Aesthetic Attributes Assessment and propose a regression model that jointly learns from MOS as well as the score of all aesthetic attributes at the same time. We construct our method by extending the scheme of data uncertainty learning and propose data covariance learning. Our method achieves the state-of-the-art performance on AAA without architectural design that trains in a totally end-to-end manner and can be easily extended to existing IAA methods.
基金This work was financially supported by National Natural Sci-ence Foundation(No.52000044)the Outstanding Youth Project of Guangdong Natural Science Foundation(No.2021B1515020051)+3 种基金the Natural Science Foundation of Guangdong Province(Nos.2021A1515012610,2019050001)Special Fund Project of Science and Technology Application in Guangdong(No.2017B020240002)National 111 project,Department of Science and Technology of Guangdong(Nos.2019JC01L203,2020B0909030004)Science and Technology Program of Guangzhou(No.202102010418).
文摘A novel benzene-ring engineered 1D/2D WO_(3)/g-C_(3)N_(4)S-scheme photocatalyst(BCNW)was rationally de-signed and successfully synthesized by the electrostatic self-assembly method.Experimental and Density Functional Theory results reveal that the integration of molecular benzene-ring in the framework of g-C_(3)N_(4)can not only narrow its bandgap and accelerate charge separation by forming a mid-state at the top of its valence band but more importantly open up a new additional bridge for speeding up the interfacial S-scheme charge transfer in BCNW.Benefitting from those multiple positive effects of benzene-ring inte-gration,as expected,BCNW S-scheme photocatalysts show superior photocatalytic H_(2)-production activity and reach 2971μmol h^(-1)g^(-1)under visible-light illumination,which is 3.35 times WO_(3)/g-C_(3)N_(4)S-scheme photocatalyst without benzene-ring integration.This work supplies an innovative strategy for the design of a high-efficiency S-scheme photocatalytic system by constructing a facile and additional molecular charge transfer channel at the interface.
基金This work was supported by the U.S.Office of Naval Research(ONR,N00014-20-1-2600)J.B.acknowledges the support from the Laboratory Directed Research and Development program at Sandia National Laboratories,a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia,LLC,a wholly owned subsidiary of Honeywell International,Inc.,for the U.S.Department of Energy's National Nuclear Security Administration under contract DE-NA-003525+1 种基金The high-resolution STEM imaging work was funded by the U.S.National Science Foundation(DMR-2016453)The article describes objective technical results and analysis.Any subjective views or opinions that might be expressed in the article do not necessarily represent the views of the U.S.Department of Energy or the United States Government。
文摘Multiferroics are an intriguing family of materials due to the simultaneous presence of two ferroic orderings,namely,ferroelectricity and ferromagnetism.They are scientifically and technologically important and have numerous potential applications,such as four-state logic memories and multiferroic tunneling junctions.However,the growth of epitaxial singlephase multiferroic thin films typically requires single crystalline oxide substrates,which hinders their future integration with Sibased devices.In this study,we report a generalized synthesis method that uses the polydimethylsiloxane(PDMS)-assisted wetetching method with an Sr_(3)Al_(2)O_(6)(SAO)sacrificial layer to transfer freestanding single-phase multiferroic Bi_(2)NiMnO_(6)(BNMO)films from conventional SrTiO_(3)(STO)substrates onto a Si wafer.The structures and properties of the films have been characterized before and after the transfer.These transferred films possess good multiferroic properties on Si wafers,indicating full compatibility with modern Si technology.This method can be generally applicable to other Bi-based multiferroic materials as well.Lastly,the original STO substrates after the transfer process have been recycled for preparing new batches of freestanding BNMO films,indicating a low-cost and sustainable method for manufacturing large-volume freestanding complex oxide thin films.
基金financially supported by the National Natural Science Foundation of China Program (No. 51602111)the Guangdong Provincial Grant (No. 2017A010104013)+3 种基金the Special Fund Project of Science and Technology Application in Guangdong(No. 2017B020240002)the Guangdong Provincial Key Laboratory of Optical Information Materials and Technology (No.2017B030301007)Guangdong Innovative Research Team Program(No. 2016ZT06C517)Science and Technology Program of Guangzhou (No. 2019050001)。
文摘Non-precious metal electrocatalyst molybdenum sulphide(MoS) and black phosphorus(BP) are highly promising catalysts for H_(2) evolution reaction(HER).However,BP is environmentally unstable and the basal planes of crystal MoS_(2) are inactive toward HER.Herein,amorphous molybdenum sulphide(MoSx)directly on BP/BiVO4 film dramatically improves the performance of photoelectrochemical water splitting compared with pure BiVO4.Additionally,we demonstrate that a BP layer,inserted between the MoSx and BiVO4,can enhance the photoelectrochemical performance and improve the stability of the electrodes.Finally,MoS_(x)/B P/BVO electrode shows the excellent current density of 2.1 mA/cm^(2) at the potential of 1.2 V(vs Ag/AgCl),which is twice higher than that of pure BVO electrode.Our novel nanostructure materials will lead to a new class of non-precious metal photocatalysts for hydrogen production.
文摘It is generally accepted that perpendicular magnetic anisotropy(PMA)magnets are preferred over in-plane magnetic anisotropy(IMA)magnets in data storage applications owing to their large thermal stability even at ultra-scaled dimensions.To efficiently and deterministically switch a PMA,out-of-plan spin current is required.However,conventional giant spin Hall effect(GSHE)materials only produce spin currents with in-plane polarization.Our work,on the other hand,demonstrated for the first time that out-of-plane spin currents can indeed be generated by applying electric filed to monolayer WSe2 at room temperature and the spin information was detected by a graphene channel.Supported by theoretical calculations,we found that the interfacial polarization between graphene and WSe2 to be^38%assuming the ferromagnetic detector's polarization efficiency to be^4%.Moreover,the spin polarization is determined by the polarity of the applied electric field.
基金supported by a grant from China National Key Clinical Specialty Construction Project (No.2022YW030009).
文摘Background:The incidence of new-onset diabetes mellitus(NODM)after distal pancreatectomy(DP)remains high.Few studies have focused on NODM in patients with pancreatic benign or low-grade malignant lesions(PBLML).This study aimed to develop and validate an effective clinical model for risk prediction and stratification of NODM after DP in patients with PBLML.Methods:A follow-up survey was conducted to investigate NODM in patients without preoperative DM who underwent DP.Four hundred and forty-eight patients from Peking Union Medical College Hospital(PUMCH)and 178 from Guangdong Provincial People’s Hospital(GDPH)met the inclusion criteria.They constituted the training cohort and the validation cohort,respectively.Univariate and multivariate Cox regression,as well as least absolute shrinkage and selection operator(LASSO)analyses,were used to identify the independent risk factors.The nomogram was constructed and verified.Concordance index(C-index),receiver operating characteristic(ROC)curve,calibration curves,and decision curve analysis(DCA)were applied to assess its predictive performance and clinical utility.Accordingly,the optimal cut-off point was determined by maximally selected rank statistics method,and the cumulative risk curves for the high-and low-risk populations were plotted to evaluate the discrimination ability of the nomogram.Results:The median follow-up duration was 42.8 months in the PUMCH cohort and 42.9 months in the GDPH cohort.The postoperative cumulative 5-year incidences of DM were 29.1%and 22.1%,respectively.Age,body mass index(BMI),length of pancreatic resection,intraoperative blood loss,and concomitant splenectomy were significant risk factors.The nomogram demonstrated significant predictive utility for post-pancreatectomy DM.The C-indexes of the nomogram were 0.739 and 0.719 in the training and validation cohorts,respectively.ROC curves demonstrated the predictive accuracy of the nomogram,and the calibration curves revealed that prediction results were in general agreement with the actual results.The considerable clinical applicability of the nomogram was certified by DCA.The optimal cut-off point for Background:The incidence of new-onset diabetes mellitus(NODM)after distal pancreatectomy(DP)remains high.Few studies have focused on NODM in patients with pancreatic benign or low-grade malignant lesions(PBLML).This study aimed to develop and validate an effective clinical model for risk prediction and stratification of NODM after DP in patients with PBLML.Methods:A follow-up survey was conducted to investigate NODM in patients without preoperative DM who underwent DP.Four hundred and forty-eight patients from Peking Union Medical College Hospital(PUMCH)and 178 from Guangdong Provincial People’s Hospital(GDPH)met the inclusion criteria.They constituted the training cohort and the validation cohort,respectively.Univariate and multivariate Cox regression,as well as least absolute shrinkage and selection operator(LASSO)analyses,were used to identify the independent risk factors.The nomogram was constructed and verified.Concordance index(C-index),receiver operating characteristic(ROC)curve,calibration curves,and decision curve analysis(DCA)were applied to assess its predictive performance and clinical utility.Accordingly,the optimal cut-off point was determined by maximally selected rank statistics method,and the cumulative risk curves for the high-and low-risk populations were plotted to evaluate the discrimination ability of the nomogram.Results:The median follow-up duration was 42.8 months in the PUMCH cohort and 42.9 months in the GDPH cohort.The postoperative cumulative 5-year incidences of DM were 29.1%and 22.1%,respectively.Age,body mass index(BMI),length of pancreatic resection,intraoperative blood loss,and concomitant splenectomy were significant risk factors.The nomogram demonstrated significant predictive utility for post-pancreatectomy DM.The C-indexes of the nomogram were 0.739 and 0.719 in the training and validation cohorts,respectively.ROC curves demonstrated the predictive accuracy of the nomogram,and the calibration curves revealed that prediction results were in general agreement with the actual results.The considerable clinical applicability of the nomogram was certified by DCA.The optimal cut-off point for risk prediction value was 2.88, and the cumulative risk curves of each cohort showed significant differences between the high- and low-risk groups. Conclusions: The nomogram could predict and identify the NODM risk population, and provide guidance to physicians in monitoring and controlling blood glucose levels in PBLML patients after DP.
