We estimate the thermal properties of unsmooth Si nanowires,considering key factors such as size(diameter),surface texture(roughness)and quantum size effects(phonon states)at different temperatures.For nanowires with ...We estimate the thermal properties of unsmooth Si nanowires,considering key factors such as size(diameter),surface texture(roughness)and quantum size effects(phonon states)at different temperatures.For nanowires with a diameter of less than 20 nm,we highlight the importance of quantum size effects in heat capacity calculations,using dispersion relations derived from the modified frequency equation for the elasticity of a rod.The thermal conductivities of nanowires with diameters of 37,56,and 115nm are predicted using the Fuchs–Sondheimer model and Soffer’s specular parameter.Notably,the roughness parameters are chosen to reflect the technological characteristics of the real surfaces.Our findings reveal that surface texture plays a significant role in thermal conductivity,particularly in the realm of ballistic heat transfer within nanowires.This study provides practical recommendations for developing new thermal management materials.展开更多
With the rapid development of the Internet globally since the 21st century,the amount of data information has increased exponentially.Data helps improve people’s livelihood and working conditions,as well as learning ...With the rapid development of the Internet globally since the 21st century,the amount of data information has increased exponentially.Data helps improve people’s livelihood and working conditions,as well as learning efficiency.Therefore,data extraction,analysis,and processing have become a hot issue for people from all walks of life.Traditional recommendation algorithm still has some problems,such as inaccuracy,less diversity,and low performance.To solve these problems and improve the accuracy and variety of the recommendation algorithms,the research combines the convolutional neural networks(CNN)and the attention model to design a recommendation algorithm based on the neural network framework.Through the text convolutional network,the input layer in CNN has transformed into two channels:static ones and non-static ones.Meanwhile,the self-attention system focuses on the system so that data can be better processed and the accuracy of feature extraction becomes higher.The recommendation algorithm combines CNN and attention system and divides the embedding layer into user information feature embedding and data name feature extraction embedding.It obtains data name features through a convolution kernel.Finally,the top pooling layer obtains the length vector.The attention system layer obtains the characteristics of the data type.Experimental results show that the proposed recommendation algorithm that combines CNN and the attention system can perform better in data extraction than the traditional CNN algorithm and other recommendation algorithms that are popular at the present stage.The proposed algorithm shows excellent accuracy and robustness.展开更多
To effectively mine the contents embedded in web images, it is useful to classify the images into different types so that they can be fed to different procedures for detailed analysis. The authors herein propose a hie...To effectively mine the contents embedded in web images, it is useful to classify the images into different types so that they can be fed to different procedures for detailed analysis. The authors herein propose a hierarchical algorithm for efficiently classifying web images into four classes. Their algorithm consists of two stages： the first stage extracts global features reflecting the distributions of color, edge and gradient, and uses a support vector machine （SVM） classifier for preliminary classification. Images assigned low confidence by the first stage classifier are processed by the second stage, which further extracts local texture features represented in the bag-of-words framework and uses another SVM classifier for final classification. In addition, they design two fusion strategies to train the second-stage classifier and generate the final prediction depending on the usage of local features in the second stage. To validate the effectiveness of proposed method, they built a database containing more than 55,000 images from various sources. On their test image set, they obtained an overall classification accuracy of 98.4% and the processing speed is over 27 fps on an Intel（R） Xeon（R） central processing unit （2.90 GHz）.展开更多
Bone marrow mesenchymal stem cells can differentiate into neurons and astrocytes after trans- plantation in the spinal cord of rats with ischemia/reperfusion injury. Although bone marrow mesenchymal stem cells are kno...Bone marrow mesenchymal stem cells can differentiate into neurons and astrocytes after trans- plantation in the spinal cord of rats with ischemia/reperfusion injury. Although bone marrow mesenchymal stem cells are known to protect against spinal cord ischemia/reperfusion injury through anti-apoptotic effects, the precise mechanisms remain unclear. In the present study, bone marrow mesenchymal stem cells were cultured and proliferated, then transplanted into rats with ischemia/reperfusion injury via retro-orbital injection. Immunohistochemistry and immunofluorescence with subsequent quantification revealed that the expression of the axonal regeneration marker, growth associated protein-43, and the neuronal marker, microtubule-as- sociated protein 2, significantly increased in rats with bone marrow mesenchymal stem cell transplantation compared with those in rats with spinal cord ischemia/reperfusion injury. Fur- thermore, the expression of the autophagy marker, microtubule-associated protein light chain 3B, and Beclin 1, was significantly reduced in rats with the bone marrow mesenchymal stem cell transplantation compared with those in rats with spinal cord ischemia/reperfusion injury. Western blot analysis showed that the expression of growth associated protein-43 and neuro- filament-H increased but light chain 3B and Beclin 1 decreased in rats with the bone marrow mesenchymal stem cell transplantation. Our results therefore suggest that bone marrow mes- enchymal stem cell transplantation promotes neurite growth and regeneration and prevents autophagy. These responses may likely be mechanisms underlying the protective effect of bone marrow mesenchymal stem cells against spinal cord ischemia/reperfusion injury.展开更多
AIM: To detect the expression of sal-like protein 4 (SALL4) and to explore its relationship with clinicopathological characteristics and prognosis of hepatocellular carcinoma (HCC).METHODS: One hundred and twenty-six ...AIM: To detect the expression of sal-like protein 4 (SALL4) and to explore its relationship with clinicopathological characteristics and prognosis of hepatocellular carcinoma (HCC).METHODS: One hundred and twenty-six samples of HCC tissue, 44 of adjacent noncancerous cirrhotic tissue and 10 of liver hemangioma tissue, were obtained from patients who underwent hepatectomy for HCC at the Fourth Hospital of Hebei Medical University. None of the patients had received any form of treatment before the operation. After resection, all the tissues were fixed in 10% neutral formaldehyde and embedded in paraffin. Expression of SALL4 was detected by immunohistochemistry. Patients were followed up for postoperative survival until February 2014. The relationships between SALL4 expression level and clinicopathological data and prognosis of HCC were analyzed.RESULTS: SALL4 expression was negative in the 10 samples of tissue from liver hemangioma, was weakly positive in the two samples from adjacent noncancerous cirrhotic tissue, and positive in 58 samples of HCC tissues. The differences were statistically significant (P < 0.05). Expression of SALL4 was higher in patients with higher α-fetoprotein (AFP) levels, portal vein tumor thrombus, and later clinical stage based on the Barcelona Clinic Liver Cancer classification (P < 0.05). Among patients with negative expression, weakly positive expression, positive expression, and strongly positive expression of SALL4, the median survival time was 39, 25, 23, and 9 mo, respectively (P < 0.001). When both AFP and SALL4 were detected, patients who were negative for both AFP and SALL4, SALL4-positive only, AFP-positive only, and positive for both AFP and SALL4, had a median survival time of 41, 38, 31, and 12 mo, respectively (P < 0.001).CONCLUSION: Expression of SALL4 is relevant to the prognosis of HCC patients. Patients with higher expression levels of SALL4 and AFP have worse prognosis.展开更多
Liver fibrosis is a wound-healing response to chronic injuries, characterized by the excessive accumulation of extracellular matrix or scar tissue within the liver;in addition, its formation is associated with multipl...Liver fibrosis is a wound-healing response to chronic injuries, characterized by the excessive accumulation of extracellular matrix or scar tissue within the liver;in addition, its formation is associated with multiple cytokines as well as several cell types and a variety of signaling pathways. When liver fibrosis is not well controlled, it can progress to liver cirrhosis, but it is reversible in principle. Thus far, no efficient therapy is available for treatment of liver fibrosis. Although liver transplantation is the preferred strategy, there are many challenges remaining in this approach, such as shortage of donor organs, immunological rejection, and surgical complications. Hence, there is a great need for an alternative therapeutic strategy. Currently, mesenchymal stem cell (MSC) therapy is considered a promising therapeutic strategy for the treatment of liver fibrosis;advantageously, the characteristics of MSCs are continuous self-renewal, proliferation, multipotent differentiation, and immunomodulatory activities. The human umbilical cord-derived (hUC)-MSCs possess not only the common attributes of MSCs but also more stable biological characteristics, relatively easy accessibility, abundant source, and no ethical issues (e.g., bone marrow being the adult source), making hUC-MSCs a good choice for treatment of liver fibrosis. In this review, we summarize the biological characteristics of hUC-MSCs and their paracrine effects, exerted by secretion of various cytokines, which ultimately promote liver repair through several signaling pathways. Additionally, we discuss the capacity of hUC-MSCs to differentiate into hepatocyte-like cells for compensating the function of existing hepatocytes, which may aid in amelioration of liver fibrosis. Finally, we discuss the current status of the research field and its future prospects.展开更多
The effects of gradient structure on the microstructure and properties of coated cemented carbides were researched with optical microscopy （OM）, scanning electron microscopy （SEM）, strength measurements, and cutti...The effects of gradient structure on the microstructure and properties of coated cemented carbides were researched with optical microscopy （OM）, scanning electron microscopy （SEM）, strength measurements, and cutting tests. It shows that vacuum sintering of WC-Ti（C, N）-TaC-Co cemented carbides results in the formation of a surface ductile zone. The ductile zone prevents crack propagation and leads to the increase of transverse rupture strength of the substrate. The impact resistance of coated gradient inserts was obviously improved on the basis of maintaining resistance to abrasion and the forming mechanism of the gradient structure was also analyzed.展开更多
BACKGROUND Poorly differentiated gastric neuroendocrine neoplasms(PDGNENs)include gastric neuroendocrine carcinoma(NEC)and mixed adenoneuroendocrine carcinoma,which are highly malignant and rare tumors,and their incid...BACKGROUND Poorly differentiated gastric neuroendocrine neoplasms(PDGNENs)include gastric neuroendocrine carcinoma(NEC)and mixed adenoneuroendocrine carcinoma,which are highly malignant and rare tumors,and their incidence has increased over the past few decades.However,the clinicopathological features and outcomes of patients with PDGNENs have not been completely elucidated.AIM To investigate the clinicopathological characteristics and prognostic factors of patients with PDGNENs.METHODS The data from seven centers in China from March 2007 to November 2019 were analyzed retrospectively.RESULTS Among the 232 patients with PDGNENs,191(82.3%)were male,with an average age of 62.83±9.11 years.One hundred and thirteen(49.34%)of 229 patients had a stage III disease and 86(37.55%)had stage IV disease.Three(1.58%)of 190 patients had no clinical symptoms,while 187(98.42%)patients presented clinical symptoms.The tumors were mainly(89.17%)solitary and located in the upper third of the stomach(cardia and fundus of stomach:115/215,53.49%).Most lesions were ulcers(157/232,67.67%),with an average diameter of 4.66±2.77 cm.In terms of tumor invasion,the majority of tumors invaded the serosa(116/198,58.58%).The median survival time of the 232 patients was 13.50 mo(7,31 mo),and the overall 1-year,3-year,and 5-year survival rates were 49%,19%,and 5%,respectively.According to univariate analysis,tumor number,tumor diameter,gastric invasion status,American Joint Committee on Cancer(AJCC)stage,and distant metastasis status were prognostic factors for patients with PDGNENs.Multivariate analysis showed that tumor number,tumor diameter,AJCC stage,and distant metastasis status were independent prognostic factors for patients with PDGNENs.CONCLUSION The overall prognosis of patients with PDGNENs is poor.The outcomes of patients with a tumor diameter>5 cm,multiple tumors,and stage IV tumors are worse than those of other patients.展开更多
Lithium-sulfur(Li-S) batteries are one of the most promising rechargeable storage devices due to the high theoretical energy density.However,the low areal sulfur loading impedes their commercial development.Herein,a 3...Lithium-sulfur(Li-S) batteries are one of the most promising rechargeable storage devices due to the high theoretical energy density.However,the low areal sulfur loading impedes their commercial development.Herein,a 3 D free-standing sulfur cathode scaffold is rationally designed and fabricated by coaxially coating polar Ti_3 C_2 T_x flakes on sulfur-impregnated carbon cloth(Ti_3 C_2 T_x@S/CC) to achieve high loading and high energy density Li-S batteries,in which,the flexible CC substrate with highly porous structure can accommodate large amounts of sulfur and ensure fast electron transfer,while the outer-coated Ti_3 C_2 T_x can serve as a polar and conductive protective layer to further promote the conductivity of the whole electrode,achieve physical blocking and chemical anchoring of lithium-polysulfides as well as catalyze their conversion.Due to these advantages,at a sulfur loading of 4 mg cm^(-2),Li-S cells with Ti_3 C_2 T_x@S/CC cathodes can deliver outstanding cycling stability(746.1 mAh g^(-1) after 200 cycles at1 C),superb rate performance(866.8 mAh g^(-1) up to 2 C) and a high specific energy density(564.2 Wh kg^(-1) after 100 cycles at 0.5 C).More significantly,they also show the commercial potential that can compete with current lithium-ion batteries due to the high areal capacity of 6.7 mAh cm^(-2) at the increased loading of 8 mg cm^(-2).展开更多
BACKGROUND Hepatic epithelioid hemangioendothelioma(HEHE)is a rare hepatic vascular tumor with unpredictable malignant potential.The etiology,characteristics,diagnosis,treatment,and prognosis of HEHE are not well-unde...BACKGROUND Hepatic epithelioid hemangioendothelioma(HEHE)is a rare hepatic vascular tumor with unpredictable malignant potential.The etiology,characteristics,diagnosis,treatment,and prognosis of HEHE are not well-understood,and largescale retrospective studies are required to understand better this disease.AIM To determine the characteristics of HEHE and identify its optimal treatments and prognostic factors.METHODS The clinical data of two patients diagnosed with HEHE at the Fourth Hospital of Hebei Medical University and 258 previously reported cases retrieved from the China National Knowledge Infrastructure and PubMed databases between 1996 and 2021 were combined and summarized.All cases were pathologically identified as HEHE.Information such as clinical features,laboratory examination findings,imaging findings,pathological characteristics,treatment,and survival periods was reviewed.Kaplan-Meir curves were used for survival analysis.Prognostic factors were identified by Cox regression analysis.RESULTS HEHE primarily affected middle-aged women.The typical manifestations included epigastric pain,hepatosplenomegaly,inappetence,distension,weight loss,and fatigue.Tumor markers were expressed normally.The incidence of extrahepatic metastasis was 34.5% at the time of diagnosis.The most common sites of extrahepatic involvement were the lungs(22.3%),lymph nodes(5.6%),peritoneum(3.6%),bones(6.6%),and spleen(5.1%).Furthermore,“capsular retraction”,“target sign”,and“lollipop sign”were the characteristic features of HEHE on imaging.The immunohistochemical profile for HEHE(expression of vascular markers,such as factor VIII-related antigen,CD31,and CD34;expression levels of D2-40)can facilitate and ensure an accurate diagnosis.The management options for patients with HEHE include liver resection(29.7%),liver transplantation(16.1%),palliative treatments(12.7%),transhepatic arterial chemotherapy and embolization(TACE,10.2%),chemotherapy(11.0%),antiangiogenic therapy(15.3%),and other treatments(5.1%);the mean survival time was 158.6,147.3,4.2,90.8,71.4,83.1,and 55.0 mo,respectively.The survival time of patients who underwent surgical treatment was longer than that of patients who did not.TACE and antiangiogenic therapy tended to prolong survival compared with other nonsurgical treatments.The 1-,5-,and 10-year survival rates were 82%,71%,and 64%,respectively.Multivariate analysis showed that liver function(P=0.045),intrahepatic metastasis(P=0.029),and treatment(P=0.045)were independent prognostic factors.The presence of extrahepatic metastases was not an independent risk factor for poor prognosis(P=0.558).CONCLUSION The clinical course of HEHE is rare and variable,and patients with intrahepatic metastases and liver dysfunction may have a poorer prognosis than those without.Surgical intervention,whether liver resection or transplantation,might be warranted regardless of extrahepatic metastasis.For patients without the option for surgery,clinicians should consider the use of TACE with antiangiogenic drugs in the treatment of HEHE.展开更多
OBJECTIVE： To identify global research trends in transplantation of neural stem cells, Schwann cells and olfactory ensheathing cells for spinal cord injury. DATA RETRIEVAL： We performed a bibliometric analysis of st...OBJECTIVE： To identify global research trends in transplantation of neural stem cells, Schwann cells and olfactory ensheathing cells for spinal cord injury. DATA RETRIEVAL： We performed a bibliometric analysis of studies on transplantation of neural stem cells, Schwann cells and olfactory ensheathing cells for spinal cord injury published from 2002 to 2011 and retrieved from the Web of Science, using the key words spinal cord injury along with either neural stem cell, Schwann cell or olfactory ensheathing cell. SELECTION CRITERIA： Inclusion criteria： （a） peer-reviewed published articles on neural stem cells, Schwann cells or olfactory ensheathing cells for spinal cord injury indexed in the Web of Science; （b） original research articles, reviews, meeting abstracts, proceedings papers, book chapters, editorial materials and news items; and （c） published between 2002 and 2011. Exclusion criteria： （a） articles that required manual searching or telephone access; （b） documents that were not published in the public domain; and （c） corrected papers. MAIN OUTCOME MEASURES： （1）Annual publication output, distribution by journal, distribution by institution and top-cited articles on neural stem cells; （2） annual publication output, distribution by journal, distribution by institution and top-cited articles on Schwann cells; （3） annual publication output, distribution by journal, distribution by institution and top-cited articles on olfactory ensheathing cells. RESULTS： This analysis, based on articles indexed in the Web of Science, identified several research trends among studies published over the past 10 years in transplantation of neural stem cells, Schwann cells and olfactory ensheathing cells for spinal cord injury. The number of publications increased over the 10-year period examined. Most papers appeared in journals with a focus on neurology, such as Journal of Neurotrauma, Experimental Neurology and Gila. Research institutes publishing on the use of neural stem cells to repair spinal cord injury were mostly in the USA and Canada. Those publishing on the use of Schwann cells were mostly in the USA and Canada as well. Those publishing on the use of olfactory ensheathing cells were mostly in the UK, the USA and Canada. CONCLUSION： On the basis of the large number of studies around the world, cell transplantation has proven to be the most promising therapeutic approach for spinal cord injury.展开更多
AIM:To develop a model using easily obtainable, objective, verifiable preoperative parameters, to help evaluate post transplant survival probability for hepatocellular carcinoma (HCC) patients with hepatitis B. METHOD...AIM:To develop a model using easily obtainable, objective, verifiable preoperative parameters, to help evaluate post transplant survival probability for hepatocellular carcinoma (HCC) patients with hepatitis B. METHODS:We retrospectively examined a cohort of 150 consecutive primary cadaveric liver transplants with HCC in our center over 6 years. Thirteen preoperative biochemical parameters and six tumor-related factors were analyzed to identify their correlation with post transplant survival using the Cox proportional-hazards regression model. The predictive power of a new model and the model for end stage liver disease was compared by the receiver operating characteristic curve. RESULTS:In univariate analysis, the factors significantly associated with post transplant survival were serum concentrations of albumin, total bilirubin, alkaline phosphatase, alpha-fetoprotein, γ-glutamyltransferase, aspartate aminotransferase, sodium, tumor diameter and the number of tumor nodules. Multivariate analysis showed alpha-fetoprotein, serum sodium, alkaline phosphatase and the number of tumor nodules were significantly associated with the post transplant outcome. Based on the four variables, we established a new model with a c-statistic of 0.72 which was significantly greater than 0.50 (P = 0.001), and the c-statistic of MELD was 0.59 (P = 0.146).CONCLUSION:The new model based on four objective tumor-related parameters has the capacity to evaluate the risk of post transplant mortality for HCC patients with hepatitis B.展开更多
BACKGROUND： Under normal conditions, excitatory amino acids are dynamically balanced with inhibitory amino acids. Excitatory amino acids have been implicated in perinatal brain injury. OBJECTIVE： To investigate diff...BACKGROUND： Under normal conditions, excitatory amino acids are dynamically balanced with inhibitory amino acids. Excitatory amino acids have been implicated in perinatal brain injury. OBJECTIVE： To investigate differences in the levels of the excitatory amino acids glutamic acid and aspartic acid, and the inhibitory amino acid gamma-aminobutyric acid （GABA） in the cerebrospinal fluid （CSF） of children with spastic cerebral palsy or athetotic cerebral palsy. DESIGN, TIME AND SETTING： Case-control exploratory observation of neurotransmitter in patients. The experiment was performed in the Pediatrics Department of the Second Affiliated Hospital of Changsha Medical College, the Cerebral Palsy Center of Xiangtan Affiliated Hospital of South China University and the Pediatrics Department of Xiangya Hospital, between February 2006 and May 2007. PARTICIPANTS： We selected 27 children with cerebral palsy, including 13 with spastic cerebral palsy and 14 with athetotic cerebral palsy. We selected 10 patients who were not affected by any neurological disease as controls. METHODS： Two mL blood-free CSF was harvested between the third and fourth lumbar vertebrae of each patient after anesthesia, and stored at -70℃. One mL CSF was mixed with 10 mg sulfosalicylic acid and placed in ice-bath for 10 minutes, then centrifuged 2 000 g for 10 minutes. The supernatant was collected for amino acid quantitation. MAIN OUTCOME MEASURES： The concentrations of glutamic acid, aspartic acid and GABA in the CSF were determined by high-performance liquid chromatography and fluorometric method. The correlation of glutamic acid, aspartic acid and GABA levels with muscular tension in children with cerebral palsy was analyzed using linear dependence. RESULTS： The concentration of GABA was significantly lower in both spastic cerebral palsy and athetotic cerebral palsy patients than in the control group （P 〈 0.01）. Glutamic acid and aspartic acid were significantly higher in both cerebral palsy groups than in the control group （P 〈 0.05-0.01）. The concentration of GABA was significantly decreased in spastic cerebral palsy patients compared with the athetotic cerebral palsy group （P 〈 0.05）. Muscular tension was positively correlated with the concentration of glutamic acid in spastic cerebral palsy patients （P 〈 0.05） but there was no significant correlation between aspartic acid or GABA and muscular tension （P 〉 0.05）. CONCLUSION： Spastic cerebral palsy and athetotic cerebral palsy patients exhibit an imbalance of excitatory amino acids and inhibitory amino acids in their CSF： an increase in glutamic acid and aspartic acid, and a decrease in GABA. Amino acid levels are different in the CSF in varied types of cerebral palsy.展开更多
In the era of science and information technology,various We-Media have come into being.We-Media is becoming an important part of people's life.It directly affects people's lifestyles and mindsets,which is part...In the era of science and information technology,various We-Media have come into being.We-Media is becoming an important part of people's life.It directly affects people's lifestyles and mindsets,which is particularly obvious in the process of education and teaching reform in colleges.There is no doubt that college students are the impelling force behind We-Media and have made great contributions to promoting the development of We-Media in China.However,consolidated with relevant practical investigations,it has been found that in the mixed We-Media environment,improper behaviors have surfaced among students,such as internet addiction,cyberbullying,and money worship,due to various inducements,thus affecting their physical and mental health.Jiang Hengyuan,a founder of vocational education development in modem China,proposed that it is not only necessary to pay attention to the training of production professions in terms of knowledge and skills,but also to the cultivation of civic morality,service morality,and national spirit while advocating the talent training mode of"double cultivation of spirit and flesh,"which points out the direction for today's youth education management.展开更多
In order to improve the properties of titanium alloys manufactured by laser melting deposition(LMD),the electroshocking treatment(EST)was proposed in this work.The effects of EST on microstructure and mechanical prope...In order to improve the properties of titanium alloys manufactured by laser melting deposition(LMD),the electroshocking treatment(EST)was proposed in this work.The effects of EST on microstructure and mechanical properties of LMD Ti-6.5Al-3.5Mo-1.5Zr-0.3Si were investigated.The results showed that the width of the heat affected band decreased and disappeared under the thermal and athermal effects of EST,resulting in the uniform microstructure.In the microstructure,theαlaths became coarser gradually,and the quantity ofα/βinterface was reduced.The reduction of the quantity ofα/βinterface leads to make less resistant to dislocation,resulting in the reduction in hardness and strength.The discontinuous grain boundaryαphase and nucleationαcolony near grain boundary inhibited the crack propagation and improved the ductility.Summary,EST can manipulate the microstructure and improve the mechanical properties of LMD titanium alloys.展开更多
基金financial support from the China Scholarship Council.
文摘We estimate the thermal properties of unsmooth Si nanowires,considering key factors such as size(diameter),surface texture(roughness)and quantum size effects(phonon states)at different temperatures.For nanowires with a diameter of less than 20 nm,we highlight the importance of quantum size effects in heat capacity calculations,using dispersion relations derived from the modified frequency equation for the elasticity of a rod.The thermal conductivities of nanowires with diameters of 37,56,and 115nm are predicted using the Fuchs–Sondheimer model and Soffer’s specular parameter.Notably,the roughness parameters are chosen to reflect the technological characteristics of the real surfaces.Our findings reveal that surface texture plays a significant role in thermal conductivity,particularly in the realm of ballistic heat transfer within nanowires.This study provides practical recommendations for developing new thermal management materials.
文摘With the rapid development of the Internet globally since the 21st century,the amount of data information has increased exponentially.Data helps improve people’s livelihood and working conditions,as well as learning efficiency.Therefore,data extraction,analysis,and processing have become a hot issue for people from all walks of life.Traditional recommendation algorithm still has some problems,such as inaccuracy,less diversity,and low performance.To solve these problems and improve the accuracy and variety of the recommendation algorithms,the research combines the convolutional neural networks(CNN)and the attention model to design a recommendation algorithm based on the neural network framework.Through the text convolutional network,the input layer in CNN has transformed into two channels:static ones and non-static ones.Meanwhile,the self-attention system focuses on the system so that data can be better processed and the accuracy of feature extraction becomes higher.The recommendation algorithm combines CNN and attention system and divides the embedding layer into user information feature embedding and data name feature extraction embedding.It obtains data name features through a convolution kernel.Finally,the top pooling layer obtains the length vector.The attention system layer obtains the characteristics of the data type.Experimental results show that the proposed recommendation algorithm that combines CNN and the attention system can perform better in data extraction than the traditional CNN algorithm and other recommendation algorithms that are popular at the present stage.The proposed algorithm shows excellent accuracy and robustness.
基金This work has been supported by the National Natural Science Foundation of China （NSFC） Grant nos. 61721004 and 61411136002.
文摘To effectively mine the contents embedded in web images, it is useful to classify the images into different types so that they can be fed to different procedures for detailed analysis. The authors herein propose a hierarchical algorithm for efficiently classifying web images into four classes. Their algorithm consists of two stages： the first stage extracts global features reflecting the distributions of color, edge and gradient, and uses a support vector machine （SVM） classifier for preliminary classification. Images assigned low confidence by the first stage classifier are processed by the second stage, which further extracts local texture features represented in the bag-of-words framework and uses another SVM classifier for final classification. In addition, they design two fusion strategies to train the second-stage classifier and generate the final prediction depending on the usage of local features in the second stage. To validate the effectiveness of proposed method, they built a database containing more than 55,000 images from various sources. On their test image set, they obtained an overall classification accuracy of 98.4% and the processing speed is over 27 fps on an Intel（R） Xeon（R） central processing unit （2.90 GHz）.
基金supported by the National Natural Science Foundation of China,No.30972153the Science and Technology Development Program of Jilin Provincial Science and Technology Department in China,No.200905183the Scientific Research Foundation of Jilin Department of Health of China,No.2008Z041
文摘Bone marrow mesenchymal stem cells can differentiate into neurons and astrocytes after trans- plantation in the spinal cord of rats with ischemia/reperfusion injury. Although bone marrow mesenchymal stem cells are known to protect against spinal cord ischemia/reperfusion injury through anti-apoptotic effects, the precise mechanisms remain unclear. In the present study, bone marrow mesenchymal stem cells were cultured and proliferated, then transplanted into rats with ischemia/reperfusion injury via retro-orbital injection. Immunohistochemistry and immunofluorescence with subsequent quantification revealed that the expression of the axonal regeneration marker, growth associated protein-43, and the neuronal marker, microtubule-as- sociated protein 2, significantly increased in rats with bone marrow mesenchymal stem cell transplantation compared with those in rats with spinal cord ischemia/reperfusion injury. Fur- thermore, the expression of the autophagy marker, microtubule-associated protein light chain 3B, and Beclin 1, was significantly reduced in rats with the bone marrow mesenchymal stem cell transplantation compared with those in rats with spinal cord ischemia/reperfusion injury. Western blot analysis showed that the expression of growth associated protein-43 and neuro- filament-H increased but light chain 3B and Beclin 1 decreased in rats with the bone marrow mesenchymal stem cell transplantation. Our results therefore suggest that bone marrow mes- enchymal stem cell transplantation promotes neurite growth and regeneration and prevents autophagy. These responses may likely be mechanisms underlying the protective effect of bone marrow mesenchymal stem cells against spinal cord ischemia/reperfusion injury.
基金Supported by the National Natural Science Foundation of China,No.81072966/H2902the Natural Science Foundation of Hebei Province,China,No.C2011206134
文摘AIM: To detect the expression of sal-like protein 4 (SALL4) and to explore its relationship with clinicopathological characteristics and prognosis of hepatocellular carcinoma (HCC).METHODS: One hundred and twenty-six samples of HCC tissue, 44 of adjacent noncancerous cirrhotic tissue and 10 of liver hemangioma tissue, were obtained from patients who underwent hepatectomy for HCC at the Fourth Hospital of Hebei Medical University. None of the patients had received any form of treatment before the operation. After resection, all the tissues were fixed in 10% neutral formaldehyde and embedded in paraffin. Expression of SALL4 was detected by immunohistochemistry. Patients were followed up for postoperative survival until February 2014. The relationships between SALL4 expression level and clinicopathological data and prognosis of HCC were analyzed.RESULTS: SALL4 expression was negative in the 10 samples of tissue from liver hemangioma, was weakly positive in the two samples from adjacent noncancerous cirrhotic tissue, and positive in 58 samples of HCC tissues. The differences were statistically significant (P < 0.05). Expression of SALL4 was higher in patients with higher α-fetoprotein (AFP) levels, portal vein tumor thrombus, and later clinical stage based on the Barcelona Clinic Liver Cancer classification (P < 0.05). Among patients with negative expression, weakly positive expression, positive expression, and strongly positive expression of SALL4, the median survival time was 39, 25, 23, and 9 mo, respectively (P < 0.001). When both AFP and SALL4 were detected, patients who were negative for both AFP and SALL4, SALL4-positive only, AFP-positive only, and positive for both AFP and SALL4, had a median survival time of 41, 38, 31, and 12 mo, respectively (P < 0.001).CONCLUSION: Expression of SALL4 is relevant to the prognosis of HCC patients. Patients with higher expression levels of SALL4 and AFP have worse prognosis.
基金Supported by the Natural Science Foundation of Jilin Province of China,No.20190201010JC
文摘Liver fibrosis is a wound-healing response to chronic injuries, characterized by the excessive accumulation of extracellular matrix or scar tissue within the liver;in addition, its formation is associated with multiple cytokines as well as several cell types and a variety of signaling pathways. When liver fibrosis is not well controlled, it can progress to liver cirrhosis, but it is reversible in principle. Thus far, no efficient therapy is available for treatment of liver fibrosis. Although liver transplantation is the preferred strategy, there are many challenges remaining in this approach, such as shortage of donor organs, immunological rejection, and surgical complications. Hence, there is a great need for an alternative therapeutic strategy. Currently, mesenchymal stem cell (MSC) therapy is considered a promising therapeutic strategy for the treatment of liver fibrosis;advantageously, the characteristics of MSCs are continuous self-renewal, proliferation, multipotent differentiation, and immunomodulatory activities. The human umbilical cord-derived (hUC)-MSCs possess not only the common attributes of MSCs but also more stable biological characteristics, relatively easy accessibility, abundant source, and no ethical issues (e.g., bone marrow being the adult source), making hUC-MSCs a good choice for treatment of liver fibrosis. In this review, we summarize the biological characteristics of hUC-MSCs and their paracrine effects, exerted by secretion of various cytokines, which ultimately promote liver repair through several signaling pathways. Additionally, we discuss the capacity of hUC-MSCs to differentiate into hepatocyte-like cells for compensating the function of existing hepatocytes, which may aid in amelioration of liver fibrosis. Finally, we discuss the current status of the research field and its future prospects.
文摘The effects of gradient structure on the microstructure and properties of coated cemented carbides were researched with optical microscopy （OM）, scanning electron microscopy （SEM）, strength measurements, and cutting tests. It shows that vacuum sintering of WC-Ti（C, N）-TaC-Co cemented carbides results in the formation of a surface ductile zone. The ductile zone prevents crack propagation and leads to the increase of transverse rupture strength of the substrate. The impact resistance of coated gradient inserts was obviously improved on the basis of maintaining resistance to abrasion and the forming mechanism of the gradient structure was also analyzed.
基金National Key R&D Program of China,No.2019YFB1309704。
文摘BACKGROUND Poorly differentiated gastric neuroendocrine neoplasms(PDGNENs)include gastric neuroendocrine carcinoma(NEC)and mixed adenoneuroendocrine carcinoma,which are highly malignant and rare tumors,and their incidence has increased over the past few decades.However,the clinicopathological features and outcomes of patients with PDGNENs have not been completely elucidated.AIM To investigate the clinicopathological characteristics and prognostic factors of patients with PDGNENs.METHODS The data from seven centers in China from March 2007 to November 2019 were analyzed retrospectively.RESULTS Among the 232 patients with PDGNENs,191(82.3%)were male,with an average age of 62.83±9.11 years.One hundred and thirteen(49.34%)of 229 patients had a stage III disease and 86(37.55%)had stage IV disease.Three(1.58%)of 190 patients had no clinical symptoms,while 187(98.42%)patients presented clinical symptoms.The tumors were mainly(89.17%)solitary and located in the upper third of the stomach(cardia and fundus of stomach:115/215,53.49%).Most lesions were ulcers(157/232,67.67%),with an average diameter of 4.66±2.77 cm.In terms of tumor invasion,the majority of tumors invaded the serosa(116/198,58.58%).The median survival time of the 232 patients was 13.50 mo(7,31 mo),and the overall 1-year,3-year,and 5-year survival rates were 49%,19%,and 5%,respectively.According to univariate analysis,tumor number,tumor diameter,gastric invasion status,American Joint Committee on Cancer(AJCC)stage,and distant metastasis status were prognostic factors for patients with PDGNENs.Multivariate analysis showed that tumor number,tumor diameter,AJCC stage,and distant metastasis status were independent prognostic factors for patients with PDGNENs.CONCLUSION The overall prognosis of patients with PDGNENs is poor.The outcomes of patients with a tumor diameter>5 cm,multiple tumors,and stage IV tumors are worse than those of other patients.
基金supported by the National Natural Science Foundation of China (51772069)。
文摘Lithium-sulfur(Li-S) batteries are one of the most promising rechargeable storage devices due to the high theoretical energy density.However,the low areal sulfur loading impedes their commercial development.Herein,a 3 D free-standing sulfur cathode scaffold is rationally designed and fabricated by coaxially coating polar Ti_3 C_2 T_x flakes on sulfur-impregnated carbon cloth(Ti_3 C_2 T_x@S/CC) to achieve high loading and high energy density Li-S batteries,in which,the flexible CC substrate with highly porous structure can accommodate large amounts of sulfur and ensure fast electron transfer,while the outer-coated Ti_3 C_2 T_x can serve as a polar and conductive protective layer to further promote the conductivity of the whole electrode,achieve physical blocking and chemical anchoring of lithium-polysulfides as well as catalyze their conversion.Due to these advantages,at a sulfur loading of 4 mg cm^(-2),Li-S cells with Ti_3 C_2 T_x@S/CC cathodes can deliver outstanding cycling stability(746.1 mAh g^(-1) after 200 cycles at1 C),superb rate performance(866.8 mAh g^(-1) up to 2 C) and a high specific energy density(564.2 Wh kg^(-1) after 100 cycles at 0.5 C).More significantly,they also show the commercial potential that can compete with current lithium-ion batteries due to the high areal capacity of 6.7 mAh cm^(-2) at the increased loading of 8 mg cm^(-2).
文摘BACKGROUND Hepatic epithelioid hemangioendothelioma(HEHE)is a rare hepatic vascular tumor with unpredictable malignant potential.The etiology,characteristics,diagnosis,treatment,and prognosis of HEHE are not well-understood,and largescale retrospective studies are required to understand better this disease.AIM To determine the characteristics of HEHE and identify its optimal treatments and prognostic factors.METHODS The clinical data of two patients diagnosed with HEHE at the Fourth Hospital of Hebei Medical University and 258 previously reported cases retrieved from the China National Knowledge Infrastructure and PubMed databases between 1996 and 2021 were combined and summarized.All cases were pathologically identified as HEHE.Information such as clinical features,laboratory examination findings,imaging findings,pathological characteristics,treatment,and survival periods was reviewed.Kaplan-Meir curves were used for survival analysis.Prognostic factors were identified by Cox regression analysis.RESULTS HEHE primarily affected middle-aged women.The typical manifestations included epigastric pain,hepatosplenomegaly,inappetence,distension,weight loss,and fatigue.Tumor markers were expressed normally.The incidence of extrahepatic metastasis was 34.5% at the time of diagnosis.The most common sites of extrahepatic involvement were the lungs(22.3%),lymph nodes(5.6%),peritoneum(3.6%),bones(6.6%),and spleen(5.1%).Furthermore,“capsular retraction”,“target sign”,and“lollipop sign”were the characteristic features of HEHE on imaging.The immunohistochemical profile for HEHE(expression of vascular markers,such as factor VIII-related antigen,CD31,and CD34;expression levels of D2-40)can facilitate and ensure an accurate diagnosis.The management options for patients with HEHE include liver resection(29.7%),liver transplantation(16.1%),palliative treatments(12.7%),transhepatic arterial chemotherapy and embolization(TACE,10.2%),chemotherapy(11.0%),antiangiogenic therapy(15.3%),and other treatments(5.1%);the mean survival time was 158.6,147.3,4.2,90.8,71.4,83.1,and 55.0 mo,respectively.The survival time of patients who underwent surgical treatment was longer than that of patients who did not.TACE and antiangiogenic therapy tended to prolong survival compared with other nonsurgical treatments.The 1-,5-,and 10-year survival rates were 82%,71%,and 64%,respectively.Multivariate analysis showed that liver function(P=0.045),intrahepatic metastasis(P=0.029),and treatment(P=0.045)were independent prognostic factors.The presence of extrahepatic metastases was not an independent risk factor for poor prognosis(P=0.558).CONCLUSION The clinical course of HEHE is rare and variable,and patients with intrahepatic metastases and liver dysfunction may have a poorer prognosis than those without.Surgical intervention,whether liver resection or transplantation,might be warranted regardless of extrahepatic metastasis.For patients without the option for surgery,clinicians should consider the use of TACE with antiangiogenic drugs in the treatment of HEHE.
基金supported by the Foundation of Science and Technology Development Program of Jilin Provincial Science and Technology Department,No.200905183
文摘OBJECTIVE： To identify global research trends in transplantation of neural stem cells, Schwann cells and olfactory ensheathing cells for spinal cord injury. DATA RETRIEVAL： We performed a bibliometric analysis of studies on transplantation of neural stem cells, Schwann cells and olfactory ensheathing cells for spinal cord injury published from 2002 to 2011 and retrieved from the Web of Science, using the key words spinal cord injury along with either neural stem cell, Schwann cell or olfactory ensheathing cell. SELECTION CRITERIA： Inclusion criteria： （a） peer-reviewed published articles on neural stem cells, Schwann cells or olfactory ensheathing cells for spinal cord injury indexed in the Web of Science; （b） original research articles, reviews, meeting abstracts, proceedings papers, book chapters, editorial materials and news items; and （c） published between 2002 and 2011. Exclusion criteria： （a） articles that required manual searching or telephone access; （b） documents that were not published in the public domain; and （c） corrected papers. MAIN OUTCOME MEASURES： （1）Annual publication output, distribution by journal, distribution by institution and top-cited articles on neural stem cells; （2） annual publication output, distribution by journal, distribution by institution and top-cited articles on Schwann cells; （3） annual publication output, distribution by journal, distribution by institution and top-cited articles on olfactory ensheathing cells. RESULTS： This analysis, based on articles indexed in the Web of Science, identified several research trends among studies published over the past 10 years in transplantation of neural stem cells, Schwann cells and olfactory ensheathing cells for spinal cord injury. The number of publications increased over the 10-year period examined. Most papers appeared in journals with a focus on neurology, such as Journal of Neurotrauma, Experimental Neurology and Gila. Research institutes publishing on the use of neural stem cells to repair spinal cord injury were mostly in the USA and Canada. Those publishing on the use of Schwann cells were mostly in the USA and Canada as well. Those publishing on the use of olfactory ensheathing cells were mostly in the UK, the USA and Canada. CONCLUSION： On the basis of the large number of studies around the world, cell transplantation has proven to be the most promising therapeutic approach for spinal cord injury.
基金The National Basic Research Program of China, 973 Program, No. 2003CB515504
文摘AIM:To develop a model using easily obtainable, objective, verifiable preoperative parameters, to help evaluate post transplant survival probability for hepatocellular carcinoma (HCC) patients with hepatitis B. METHODS:We retrospectively examined a cohort of 150 consecutive primary cadaveric liver transplants with HCC in our center over 6 years. Thirteen preoperative biochemical parameters and six tumor-related factors were analyzed to identify their correlation with post transplant survival using the Cox proportional-hazards regression model. The predictive power of a new model and the model for end stage liver disease was compared by the receiver operating characteristic curve. RESULTS:In univariate analysis, the factors significantly associated with post transplant survival were serum concentrations of albumin, total bilirubin, alkaline phosphatase, alpha-fetoprotein, γ-glutamyltransferase, aspartate aminotransferase, sodium, tumor diameter and the number of tumor nodules. Multivariate analysis showed alpha-fetoprotein, serum sodium, alkaline phosphatase and the number of tumor nodules were significantly associated with the post transplant outcome. Based on the four variables, we established a new model with a c-statistic of 0.72 which was significantly greater than 0.50 (P = 0.001), and the c-statistic of MELD was 0.59 (P = 0.146).CONCLUSION:The new model based on four objective tumor-related parameters has the capacity to evaluate the risk of post transplant mortality for HCC patients with hepatitis B.
基金a grant from Health Department of Hunan Province,No.B2006-204
文摘BACKGROUND： Under normal conditions, excitatory amino acids are dynamically balanced with inhibitory amino acids. Excitatory amino acids have been implicated in perinatal brain injury. OBJECTIVE： To investigate differences in the levels of the excitatory amino acids glutamic acid and aspartic acid, and the inhibitory amino acid gamma-aminobutyric acid （GABA） in the cerebrospinal fluid （CSF） of children with spastic cerebral palsy or athetotic cerebral palsy. DESIGN, TIME AND SETTING： Case-control exploratory observation of neurotransmitter in patients. The experiment was performed in the Pediatrics Department of the Second Affiliated Hospital of Changsha Medical College, the Cerebral Palsy Center of Xiangtan Affiliated Hospital of South China University and the Pediatrics Department of Xiangya Hospital, between February 2006 and May 2007. PARTICIPANTS： We selected 27 children with cerebral palsy, including 13 with spastic cerebral palsy and 14 with athetotic cerebral palsy. We selected 10 patients who were not affected by any neurological disease as controls. METHODS： Two mL blood-free CSF was harvested between the third and fourth lumbar vertebrae of each patient after anesthesia, and stored at -70℃. One mL CSF was mixed with 10 mg sulfosalicylic acid and placed in ice-bath for 10 minutes, then centrifuged 2 000 g for 10 minutes. The supernatant was collected for amino acid quantitation. MAIN OUTCOME MEASURES： The concentrations of glutamic acid, aspartic acid and GABA in the CSF were determined by high-performance liquid chromatography and fluorometric method. The correlation of glutamic acid, aspartic acid and GABA levels with muscular tension in children with cerebral palsy was analyzed using linear dependence. RESULTS： The concentration of GABA was significantly lower in both spastic cerebral palsy and athetotic cerebral palsy patients than in the control group （P 〈 0.01）. Glutamic acid and aspartic acid were significantly higher in both cerebral palsy groups than in the control group （P 〈 0.05-0.01）. The concentration of GABA was significantly decreased in spastic cerebral palsy patients compared with the athetotic cerebral palsy group （P 〈 0.05）. Muscular tension was positively correlated with the concentration of glutamic acid in spastic cerebral palsy patients （P 〈 0.05） but there was no significant correlation between aspartic acid or GABA and muscular tension （P 〉 0.05）. CONCLUSION： Spastic cerebral palsy and athetotic cerebral palsy patients exhibit an imbalance of excitatory amino acids and inhibitory amino acids in their CSF： an increase in glutamic acid and aspartic acid, and a decrease in GABA. Amino acid levels are different in the CSF in varied types of cerebral palsy.
基金the 2020-2021 Lianyungang Social Science Fund Project:“Research on Jiang Hengyuan’s Views on Youth and Its Enlightenment to Youth Education in Higher Vocational Colleges”(Number:20LKT2036,Project Director:Yin Fei).
文摘In the era of science and information technology,various We-Media have come into being.We-Media is becoming an important part of people's life.It directly affects people's lifestyles and mindsets,which is particularly obvious in the process of education and teaching reform in colleges.There is no doubt that college students are the impelling force behind We-Media and have made great contributions to promoting the development of We-Media in China.However,consolidated with relevant practical investigations,it has been found that in the mixed We-Media environment,improper behaviors have surfaced among students,such as internet addiction,cyberbullying,and money worship,due to various inducements,thus affecting their physical and mental health.Jiang Hengyuan,a founder of vocational education development in modem China,proposed that it is not only necessary to pay attention to the training of production professions in terms of knowledge and skills,but also to the cultivation of civic morality,service morality,and national spirit while advocating the talent training mode of"double cultivation of spirit and flesh,"which points out the direction for today's youth education management.
基金This work was financially supported by the National Natural Science Foundation of China(Grant Nos.51975441 and 52271135)the Innovation Funding Project of National Engineering and Research Center for Commercial Aircraft Manufacturing(No.COMAC-SFGS-2022-1871)+6 种基金the Major Research Plan of the National Natural Science Foundation of China(Grant No.92266102)the Natural Science Foundation of Hubei Province(Grant No.2022CFB492)the Knowledge Innovation Program of Wuhan-Basic Research(No.2022010801010174)the Application Foundation Frontier Project of Wuhan(No.2020010601012171)the“Chu Tian Scholar”project of Hubei Province(No.CTXZ2017-05)the Overseas Expertise Introduction Project for Discipline Innovation(No.B17034)Innovative Research Team Development Program of Ministry of Education of China(No.IRT_17R83).
文摘In order to improve the properties of titanium alloys manufactured by laser melting deposition(LMD),the electroshocking treatment(EST)was proposed in this work.The effects of EST on microstructure and mechanical properties of LMD Ti-6.5Al-3.5Mo-1.5Zr-0.3Si were investigated.The results showed that the width of the heat affected band decreased and disappeared under the thermal and athermal effects of EST,resulting in the uniform microstructure.In the microstructure,theαlaths became coarser gradually,and the quantity ofα/βinterface was reduced.The reduction of the quantity ofα/βinterface leads to make less resistant to dislocation,resulting in the reduction in hardness and strength.The discontinuous grain boundaryαphase and nucleationαcolony near grain boundary inhibited the crack propagation and improved the ductility.Summary,EST can manipulate the microstructure and improve the mechanical properties of LMD titanium alloys.
