BACKGROUND Endogenous regeneration of pancreatic isletβ-cells is a path to cure both type 1 and advanced type 2 diabetes.Pancreatic cancer cell line-1(PANC-1),a human pancreatic islet progenitor cell line,can be indu...BACKGROUND Endogenous regeneration of pancreatic isletβ-cells is a path to cure both type 1 and advanced type 2 diabetes.Pancreatic cancer cell line-1(PANC-1),a human pancreatic islet progenitor cell line,can be induced by trypsin to differentiate into insulin-secreting islet-like aggregates(ILAs).However,the underlying mechanism has not been explored.AIM To explore the mechanism and signaling pathway of trypsin-induced differentiation of islet progenitor cells into insulin-secreting cells.METHODS PANC-1 cells were induced by trypsin to form ILAs and differentiate into insulinsecreting cells.Clustered regularly interspaced short palindromic repeats(CRISPR)-associated protein 9 knockout and small interfering RNA knockdown techniques were used to investigate membrane proteins and downstream signaling pathways involved in the process.RESULTS The extracellular domain of membrane receptor E-cadherin hydrolyzed by trypsin induced the aggregation of PANC-1 cells and stimulated E-cadherin-recruited casein kinase-1γ3,which specifically phosphorylated the Ser655/Thr658 site ofα-catenin in the cadherin-catenin complex,participating in the process of PANC-1 differentiation and affecting the maturation of differentiated ILAs.CONCLUSION The current study reveals the mechanism by which trypsin promotes PANC-1 cell differentiation into islet-like cells,providing a novel approach for endogenous isletβ-cell regeneration.展开更多
With growing concerns regarding electromagnetic pollution,low-cost,environmentally friendly,and high-performance electromagnetic wave absorption(EWA)materials have attracted significant attention.This paper reports on...With growing concerns regarding electromagnetic pollution,low-cost,environmentally friendly,and high-performance electromagnetic wave absorption(EWA)materials have attracted significant attention.This paper reports on the synthesis of porous Fe_(3)O_(4)/C composites that incorporate dielectric and magnetic loss mechanisms via the carbothermal reduction method and optimization of waste ratio to enhance EWA performance.The Fe_(3)O_(4)/C composites with 10wt%soybean residues(Fe_(3)O_(4)/C-10),demonstrated the best EWA performance,achieving the minimum reflection loss of−56.4 dB and a bandwidth of 2.14 GHz at a thickness of 2.23 mm.This enhanced EWA performance is primarily attributable to improved impedance matching and the synergistic effect between dielectric and magnetic losses.Furthermore,radar cross-sectional simulations confirmed the practical feasibility of the porous Fe_(3)O_(4)/C composites.This study proposes a viable strategy for utilizing soybean residue and electrolytic manganese residue,highlighting their potential applications in EWA.展开更多
In the age of big data,ensuring data privacy while enabling efficient encrypted data retrieval has become a critical challenge.Traditional searchable encryption schemes face difficulties in handling complex semantic q...In the age of big data,ensuring data privacy while enabling efficient encrypted data retrieval has become a critical challenge.Traditional searchable encryption schemes face difficulties in handling complex semantic queries.Additionally,they typically rely on honest but curious cloud servers,which introduces the risk of repudiation.Furthermore,the combined operations of search and verification increase system load,thereby reducing performance.Traditional verification mechanisms,which rely on complex hash constructions,suffer from low verification efficiency.To address these challenges,this paper proposes a blockchain-based contextual semantic-aware ciphertext retrieval scheme with efficient verification.Building on existing single and multi-keyword search methods,the scheme uses vector models to semantically train the dataset,enabling it to retain semantic information and achieve context-aware encrypted retrieval,significantly improving search accuracy.Additionally,a blockchain-based updatable master-slave chain storage model is designed,where the master chain stores encrypted keyword indexes and the slave chain stores verification information generated by zero-knowledge proofs,thus balancing system load while improving search and verification efficiency.Finally,an improved non-interactive zero-knowledge proof mechanism is introduced,reducing the computational complexity of verification and ensuring efficient validation of search results.Experimental results demonstrate that the proposed scheme offers stronger security,balanced overhead,and higher search verification efficiency.展开更多
Hypoxiainducible factor1 and its specific target gene heme oxygenase1, are involved in acute cerebral ischemia. However, very few studies have examined in detail the changes in the hy poxiainducible factor1/heme oxyge...Hypoxiainducible factor1 and its specific target gene heme oxygenase1, are involved in acute cerebral ischemia. However, very few studies have examined in detail the changes in the hy poxiainducible factor1/heme oxygenase1 signaling pathway in chronic cerebral ischemia. In this study, a rat model of chronic cerebral ischemia was established by permanent bilateral common carotid artery occlusion, and these rats were treated with intragastric cilostazol （30 mg/kg） for 9 weeks. Morris water maze results showed that cognitive impairment gradually worsened as the cerebral ischemia proceeded. Immunohistochemistry, semiquantitative PCR and western blot analysis showed that hypoxiainducible factorla and heme oxygenase1 expression levels in creased after chronic cerebral ischemia, with hypoxiainducible factorla expression peaking at 3 weeks and heme oxygenase1 expression peaking at 6 weeks. These results suggest that the elevated levels of hypoxiainducible factorla may upregulate heine oxygenase1 expression fol lowing chronic cerebral ischemia and that the hypoxiainducible factor1/heme oxygenase1 sig naling pathway is involved in the development of cognitive impairment induced by chronic cerebral ischemia. Cilostazol treatment alleviated the cognitive impairment in rats with chronic cerebral ischemia, decreased hypoxiainducible factorla and heme oxygenase1 expression levels, and reduced apoptosis in the frontal cortex. These findings demonstrate that cilostazol can protect against cognitive impairment induced by chronic cerebral ischemic injury through an antiapoptotic mechanism.展开更多
Objective： Mesenchymal stem cell （MSC） transplantation is a promising therapy for ischemic heart diseases. However, poor cell survival after transplantation greatly limits the therapeutic efficacy of MSCs. The purp...Objective： Mesenchymal stem cell （MSC） transplantation is a promising therapy for ischemic heart diseases. However, poor cell survival after transplantation greatly limits the therapeutic efficacy of MSCs. The purpose of this study was to investigate the protective effect of angiopoietin-1 （Angl） preconditioning on MSC survival and sub- sequent heart function improvement after transplantation. Methods： MSCs were cultured with or without 50 ng/ml Angl in complete medium for 24 h prior to experiments on cell survival and transplantation. 3-（4,5- Dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） and Hoechst staining were applied to evaluate MSC survival after serum deprivation in vitro, while cell survival in vivo was detected by terminal deoxynucleotidyl trans- ferase biotin-dUPT nick end labeling （TUNEL） assay 24 and 72 h after transplantation. Heart function and infarct size were measured four weeks later by small animal echocardiography and Masson＇s trichrome staining, respectively. Results： Angl preconditioning induced Akt phosphorylation and increased expression of Bcl-2 and the ratio of Bcl-2/Bax. In comparison with non-preconditioned MSCs, Angl-preconditioned cell survival was significantly in- creased while the apoptotic rate decreased in vitro. However, the PI3K/Akt pathway inhibitor, LY294002, abrogated the protective effect of Angl preconditioning. After transplantation, the Angl-preconditioned-MSC group showed a lower death rate, smaller infarct size, and better heart functional recovery compared to the non-preconditioned-MSC group. Conclusions： Angl preconditioning enhances MSC survival, contributing to further improvement of heart function.展开更多
BACKGROUND Duchenne muscular dystrophy(DMD),which is caused by a mutation/deletion in the dystrophin gene on the X-chromosome,is the most common type of neuromuscular disorder in pediatrics.Skeletal muscle weakness pr...BACKGROUND Duchenne muscular dystrophy(DMD),which is caused by a mutation/deletion in the dystrophin gene on the X-chromosome,is the most common type of neuromuscular disorder in pediatrics.Skeletal muscle weakness progressively develops in DMD patients and usually leads to respiratory failure in the early adolescent years.Cardiac muscle is frequently affected in DMD patients,which leads to a high burden of cardiomyopathy and heart failure.In the era of improved respiratory care,cardiac deaths are becoming the major cause of mortality in DMD patients.CASE SUMMARY We report the case of a 15-year-old boy who presented to the hospital due to recurrent orthopnea for 6 mo and palpitations for 4 mo.He was diagnosed with progressive muscular dystrophy at the age of 3 years and was confined to a wheelchair at 12 years.He was prescribed diuretics and digoxin at the outpatient clinic;however,his symptoms did not resolve.Sacubitril/valsartan was added 1 mo prior to presentation,but he experienced recurrent episodes of palpitations.The electrocardiogram showed atrial tachycardia with a heart rate of 201 bpm,and he was then hospitalized.Hypotension was found following the administration of sacubitril/valsartan tablets;he could not tolerate even a small dose,always developing tachyarrhythmia.His symptoms were relieved after discontinuing sacubitril/valsartan,and his heart rate was controlled by a small dose of metoprolol tartrate and digoxin.Atrial tachycardia spontaneously converted in this patient,and his symptoms attenuated in the following 6 mo,without palpitation episodes.CONCLUSION Blood pressure should be closely monitored in DMD patients with advanced heart failure when taking sacubitril/valsartan.展开更多
A series of experimental studies was carried out to investigate the influences of pretorsion on microstructure evolution, mechanical properties, and fracture appearance of pure titanium subjected to subsequent tension...A series of experimental studies was carried out to investigate the influences of pretorsion on microstructure evolution, mechanical properties, and fracture appearance of pure titanium subjected to subsequent tension deformation. An introduction of pre-torsion strain can improve the materials＇ mechanical properties through micro hardness evaluation. That is, the micro hardness of tensile samples with pre-torsion deformation is much higher than that of samples processed by single torsion or tension. It can be seen from the microstructure that pre-torsion deformation can be used to refine grains better and control grains＇ morphology by combining subsequent tension. The results indicate that the grains are refined most evidently for tensile samples with 2 turn pre-torsion deformation. Moreover, fracture analysis indicates that tensile samples with pre-torsion strain can present good comprehensive performance. In conclusion, pre-torsion deformation plays an important role in improving comprehensive performance and controlling microstructure evolution on pure titanium subjected to later tension deformation.展开更多
The Stinger PDC cutter has high rock-breaking efficiency and excellent impact and wear resistance, which can significantly increase the rate of penetration (ROP) and extend PDC bit life for drilling hard and abrasive ...The Stinger PDC cutter has high rock-breaking efficiency and excellent impact and wear resistance, which can significantly increase the rate of penetration (ROP) and extend PDC bit life for drilling hard and abrasive formation. The knowledge of force response and mechanical specific energy (MSE) for the Stinger PDC cutter is of great importance for improving the cutter's performance and optimizing the hybrid PDC bit design. In this paper, 87 single cutter tests were conducted on the granite. A new method for precisely obtaining the rock broken volume was proposed. The influences of cutting depth, cutting angle, and cutting speed on cutting force and MSE were analyzed. Besides, a phenomenological cutting force model of the Stinger PDC cutter was established by regression of experimental data. Moreover, the surface topography and fracture morphology of the cutting groove and large size cuttings were measured by a 3D profilometer and a scanning electron microscope (SEM). Finally, the rock-breaking mechanism of the Stinger PDC cutter was illustrated. The results indicated that the cutting depth has the greatest influence on the cutting force and MSE, while the cutting speed has no obvious effects, especially at low cutting speeds. As the increase of cutting depth, the cutting force increases linearly, and MSE reduces with a quadratic polynomial relationship. When the cutting angle raises from 10° to 30°, the cutting force increases linearly, and the MSE firstly decreases and then increases. The optimal cutting angle for breaking rock is approximately 20°. The Stinger PDC cutter breaks granite mainly by high concentrated point loading and tensile failure, which can observably improve the rock breaking efficiency. The key findings of this work will help to reveal the rock-breaking mechanisms and optimize the cutter arrangement for the Stinger PDC cutter.展开更多
Objective:To investigate the effect of Guangdong Shenqu(GSQ)on intestinal flora structure in mice with food stagnation through 16S rDNA sequencing.Methods: Mice were randomly assigned to control,model,GSQ low-dose(GSQ...Objective:To investigate the effect of Guangdong Shenqu(GSQ)on intestinal flora structure in mice with food stagnation through 16S rDNA sequencing.Methods: Mice were randomly assigned to control,model,GSQ low-dose(GSQL),GSQ medium-dose(GSQM),GSQ high-dose(GSQH),and lacidophilin tablets(LAB)groups,with each group containing 10 mice.A food stagnation and internal heat mouse model was established through intragastric administration of a mixture of beeswax and olive oil(1:15).The control group was administered normal saline,and the model group was administered beeswax and olive oil to maintain a state.The GSQL(2 g/kg),GSQM(4 g/kg),GSQH(8 g/kg),and LAB groups(0.625 g/kg)were administered corresponding drugs for 5 d.After administration,16S rDNA sequencing was performed to assess gut microbiota in mouse fecal samples.Results: The model group exhibited significant intestinal flora changes.Following GSQ administration,the abundance and diversity index of the intestinal flora increased significantly,the number of bacterial species was regulated,andαandβdiversity were improved.GSQ administration increased the abundance of probiotics,including Clostridia,Lachnospirales,and Lactobacillus,whereas the abundance of conditional pathogenic bacteria,such as Allobaculum,Erysipelotrichaceae,and Bacteroides decreased.Functional prediction analysis indicated that the pathogenesis of food stagnation and GSQ intervention were primarily associated with carbohydrate,lipid,and amino acid metabolism,among other metabolic pathways.Conclusion: The digestive mechanism of GSQ may be attributed to its role in restoring diversity and abundance within the intestinal flora,thereby improving the composition and structure of the intestinal flora in mice and subsequently influencing the regulation of metabolic pathways.展开更多
In this paper, a coordinate transformation method (CTM) is employed to numerically solve the Poisson–Nernst–Planck (PNP) equation and Navier–Stokes (NS) equations for studying the traveling-wave electroosmotic flow...In this paper, a coordinate transformation method (CTM) is employed to numerically solve the Poisson–Nernst–Planck (PNP) equation and Navier–Stokes (NS) equations for studying the traveling-wave electroosmotic flow (TWEF) in a two-dimensional microchannel. Numerical solutions indicate that the numerical solutions of TWEF with and without the coordinate transformation are in good agreement, while CTM effectively improves stability and convergence rate of the numerical solution, and saves computational cost. It is found that the averaged flow velocity of TWEF in a micro-channel strongly depends on frequency of the electric field. Flow rate achieves a maximum around the charge frequency of the electric double layer. The approximate solutions of TWEF with slip boundary conditions are also presented for comparison. It is shown that the NS solution with slip boundary conditions agree well with those of complete PNP-NS equations in the cases of small ratios of Electric double layer(EDL) thickness to channel depth(λD/H). The NS solution with slip boundary conditions over-estimates the electroosmotic flow velocity as this ratio(λD/H) is large.展开更多
In the face of multiple challenges brought by the changes of global climate and environment,developing clean energy and updating green energy storage equipment are important ways to achieve carbon peak and carbon neut...In the face of multiple challenges brought by the changes of global climate and environment,developing clean energy and updating green energy storage equipment are important ways to achieve carbon peak and carbon neutrality.Aqueous batteries have become a research hotspot due to their advantages of using the multivalent charge carrier,high ionic conductivity,environmental friendliness and cost effectiveness.In this work,the Cu_(2)Se@C(Cu_(2)Se coated on carbon clothes)thin film with a three-dimensional braided structure is fabricated by a simple electrochemical deposition method for Cu^(2+)storage for the first time.Compared with the commercial Cu_(2)Se powder,the well-designed Cu_(2)Se@C film shows enhanced specific capacity(640 mAh/g at 0.5 A/g)and rate performance(542 mAh/g at 5 A/g)as well as superior cycling stability(82.7%capacity retention after 1000 cycles at 1 A/g).The Cu^(2+)storage mechanism of the Cu_(2)Se@C electrode is based on a reversible phase transition process of Cu_(2)Se←→Cu_(2-x)Se←→CuSe←→CuSe_(2).In kinetic characteristic analysis,the Cu_(2)Se@C electrode demonstrates faster Cu^(2+)diffusion in discharge process than charge process resulting from the phase transition and the variation of interplanar spacing.This work highlights a facile one-piece design strategy and opens a new gateway for the exploration of advanced aqueous energy storage systems.展开更多
Introduction: Langerhans cell histiocytosis (LCH) is a group of idiopathic disorders characterized by the proliferation of specialized bone marrow-derived Langerhans cells (LCs) and mature eosinophils, resulting in so...Introduction: Langerhans cell histiocytosis (LCH) is a group of idiopathic disorders characterized by the proliferation of specialized bone marrow-derived Langerhans cells (LCs) and mature eosinophils, resulting in solitary or few, indolent and chronic, lesions of bone or other organs called eosinophilic granulomas. Calvarial LCH is quite rare and an underappreciated differential etiology of skull lesions. We present a most unusual case of a young child with hyperacutely symptomatic langerhans histiocytosis of the skull. Method: A 7-year-old male presented with a history of increasing (progressive) frontal headaches of 8 days duration, unaccompanied by associated nausea, vomiting, or diplopia. His only additional complaint was a hard bump on his forehead. MRI and CT done in the ER identified a right fronto-parietal lesion with associated skull erosion. Nuclear medicine and SPECT studies confirmed an erosive skull lesion without significant metabolic activity. A right frontal craniectomy and excision was performed. Results: A soft, rubbery well-circumcised mass coming from the diploic layer of the skull with involvement of bone was identified. The mass had eroded both the outer and inner table of the skull, and the involved area of the right frontal bone was resected. Intra-operative histo-pathologic analysis of the lesion revealed Langerhans cell histiocytosis without involvement of the dura. The patient experienced no neurological worsening as a result of the resection. He was discharged home in stable condition. Conclusion: LCH lesions of the skull are common findings, however, this focal hyperacute symptomatic presentation is most rare and should not deter us from anticipating an erosive bony tumor and planning timely surgical management.展开更多
基金Supported by the National Natural Science Foundation of China,No.82073908.
文摘BACKGROUND Endogenous regeneration of pancreatic isletβ-cells is a path to cure both type 1 and advanced type 2 diabetes.Pancreatic cancer cell line-1(PANC-1),a human pancreatic islet progenitor cell line,can be induced by trypsin to differentiate into insulin-secreting islet-like aggregates(ILAs).However,the underlying mechanism has not been explored.AIM To explore the mechanism and signaling pathway of trypsin-induced differentiation of islet progenitor cells into insulin-secreting cells.METHODS PANC-1 cells were induced by trypsin to form ILAs and differentiate into insulinsecreting cells.Clustered regularly interspaced short palindromic repeats(CRISPR)-associated protein 9 knockout and small interfering RNA knockdown techniques were used to investigate membrane proteins and downstream signaling pathways involved in the process.RESULTS The extracellular domain of membrane receptor E-cadherin hydrolyzed by trypsin induced the aggregation of PANC-1 cells and stimulated E-cadherin-recruited casein kinase-1γ3,which specifically phosphorylated the Ser655/Thr658 site ofα-catenin in the cadherin-catenin complex,participating in the process of PANC-1 differentiation and affecting the maturation of differentiated ILAs.CONCLUSION The current study reveals the mechanism by which trypsin promotes PANC-1 cell differentiation into islet-like cells,providing a novel approach for endogenous isletβ-cell regeneration.
基金supported by the National Natural Science Foundation of China(No.52471221)the Natural Science Foundation of Hunan Province,China(No.2024JJ7145)the National Sustainable Development Agenda Innovation Demonstration Zone Hunan special project,China(No.2022sfq09).
文摘With growing concerns regarding electromagnetic pollution,low-cost,environmentally friendly,and high-performance electromagnetic wave absorption(EWA)materials have attracted significant attention.This paper reports on the synthesis of porous Fe_(3)O_(4)/C composites that incorporate dielectric and magnetic loss mechanisms via the carbothermal reduction method and optimization of waste ratio to enhance EWA performance.The Fe_(3)O_(4)/C composites with 10wt%soybean residues(Fe_(3)O_(4)/C-10),demonstrated the best EWA performance,achieving the minimum reflection loss of−56.4 dB and a bandwidth of 2.14 GHz at a thickness of 2.23 mm.This enhanced EWA performance is primarily attributable to improved impedance matching and the synergistic effect between dielectric and magnetic losses.Furthermore,radar cross-sectional simulations confirmed the practical feasibility of the porous Fe_(3)O_(4)/C composites.This study proposes a viable strategy for utilizing soybean residue and electrolytic manganese residue,highlighting their potential applications in EWA.
基金supported in part by the National Natural Science Foundation of China under Grant 62262073in part by the Yunnan Provincial Ten Thousand People Program for Young Top Talents under Grant YNWR-QNBJ-2019-237in part by the Yunnan Provincial Major Science and Technology Special Program under Grant 202402AD080002.
文摘In the age of big data,ensuring data privacy while enabling efficient encrypted data retrieval has become a critical challenge.Traditional searchable encryption schemes face difficulties in handling complex semantic queries.Additionally,they typically rely on honest but curious cloud servers,which introduces the risk of repudiation.Furthermore,the combined operations of search and verification increase system load,thereby reducing performance.Traditional verification mechanisms,which rely on complex hash constructions,suffer from low verification efficiency.To address these challenges,this paper proposes a blockchain-based contextual semantic-aware ciphertext retrieval scheme with efficient verification.Building on existing single and multi-keyword search methods,the scheme uses vector models to semantically train the dataset,enabling it to retain semantic information and achieve context-aware encrypted retrieval,significantly improving search accuracy.Additionally,a blockchain-based updatable master-slave chain storage model is designed,where the master chain stores encrypted keyword indexes and the slave chain stores verification information generated by zero-knowledge proofs,thus balancing system load while improving search and verification efficiency.Finally,an improved non-interactive zero-knowledge proof mechanism is introduced,reducing the computational complexity of verification and ensuring efficient validation of search results.Experimental results demonstrate that the proposed scheme offers stronger security,balanced overhead,and higher search verification efficiency.
基金supported by the Natural Science Fundation of Jilin Province in China, No.200705272
文摘Hypoxiainducible factor1 and its specific target gene heme oxygenase1, are involved in acute cerebral ischemia. However, very few studies have examined in detail the changes in the hy poxiainducible factor1/heme oxygenase1 signaling pathway in chronic cerebral ischemia. In this study, a rat model of chronic cerebral ischemia was established by permanent bilateral common carotid artery occlusion, and these rats were treated with intragastric cilostazol （30 mg/kg） for 9 weeks. Morris water maze results showed that cognitive impairment gradually worsened as the cerebral ischemia proceeded. Immunohistochemistry, semiquantitative PCR and western blot analysis showed that hypoxiainducible factorla and heme oxygenase1 expression levels in creased after chronic cerebral ischemia, with hypoxiainducible factorla expression peaking at 3 weeks and heme oxygenase1 expression peaking at 6 weeks. These results suggest that the elevated levels of hypoxiainducible factorla may upregulate heine oxygenase1 expression fol lowing chronic cerebral ischemia and that the hypoxiainducible factor1/heme oxygenase1 sig naling pathway is involved in the development of cognitive impairment induced by chronic cerebral ischemia. Cilostazol treatment alleviated the cognitive impairment in rats with chronic cerebral ischemia, decreased hypoxiainducible factorla and heme oxygenase1 expression levels, and reduced apoptosis in the frontal cortex. These findings demonstrate that cilostazol can protect against cognitive impairment induced by chronic cerebral ischemic injury through an antiapoptotic mechanism.
基金supported by the Natural Science Foundation of Zhejiang Province (No. Y2100362)the Qianjiang Talents Project of Science and Technology Department of Zhejiang Province (No. 2011R10022), China
文摘Objective： Mesenchymal stem cell （MSC） transplantation is a promising therapy for ischemic heart diseases. However, poor cell survival after transplantation greatly limits the therapeutic efficacy of MSCs. The purpose of this study was to investigate the protective effect of angiopoietin-1 （Angl） preconditioning on MSC survival and sub- sequent heart function improvement after transplantation. Methods： MSCs were cultured with or without 50 ng/ml Angl in complete medium for 24 h prior to experiments on cell survival and transplantation. 3-（4,5- Dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） and Hoechst staining were applied to evaluate MSC survival after serum deprivation in vitro, while cell survival in vivo was detected by terminal deoxynucleotidyl trans- ferase biotin-dUPT nick end labeling （TUNEL） assay 24 and 72 h after transplantation. Heart function and infarct size were measured four weeks later by small animal echocardiography and Masson＇s trichrome staining, respectively. Results： Angl preconditioning induced Akt phosphorylation and increased expression of Bcl-2 and the ratio of Bcl-2/Bax. In comparison with non-preconditioned MSCs, Angl-preconditioned cell survival was significantly in- creased while the apoptotic rate decreased in vitro. However, the PI3K/Akt pathway inhibitor, LY294002, abrogated the protective effect of Angl preconditioning. After transplantation, the Angl-preconditioned-MSC group showed a lower death rate, smaller infarct size, and better heart functional recovery compared to the non-preconditioned-MSC group. Conclusions： Angl preconditioning enhances MSC survival, contributing to further improvement of heart function.
基金Natural Science Foundation of Zhejiang Province,No.LQ16H020004
文摘BACKGROUND Duchenne muscular dystrophy(DMD),which is caused by a mutation/deletion in the dystrophin gene on the X-chromosome,is the most common type of neuromuscular disorder in pediatrics.Skeletal muscle weakness progressively develops in DMD patients and usually leads to respiratory failure in the early adolescent years.Cardiac muscle is frequently affected in DMD patients,which leads to a high burden of cardiomyopathy and heart failure.In the era of improved respiratory care,cardiac deaths are becoming the major cause of mortality in DMD patients.CASE SUMMARY We report the case of a 15-year-old boy who presented to the hospital due to recurrent orthopnea for 6 mo and palpitations for 4 mo.He was diagnosed with progressive muscular dystrophy at the age of 3 years and was confined to a wheelchair at 12 years.He was prescribed diuretics and digoxin at the outpatient clinic;however,his symptoms did not resolve.Sacubitril/valsartan was added 1 mo prior to presentation,but he experienced recurrent episodes of palpitations.The electrocardiogram showed atrial tachycardia with a heart rate of 201 bpm,and he was then hospitalized.Hypotension was found following the administration of sacubitril/valsartan tablets;he could not tolerate even a small dose,always developing tachyarrhythmia.His symptoms were relieved after discontinuing sacubitril/valsartan,and his heart rate was controlled by a small dose of metoprolol tartrate and digoxin.Atrial tachycardia spontaneously converted in this patient,and his symptoms attenuated in the following 6 mo,without palpitation episodes.CONCLUSION Blood pressure should be closely monitored in DMD patients with advanced heart failure when taking sacubitril/valsartan.
基金supports received from the National Natural Science Foundation of China (No. 51275414)the Aeronautical Science Foundation of China (No. 2011ZE53059)+1 种基金the Research Fund of the State Key Laboratory of Solidification Processing (NWPU) of China (No. 130-QP-2015)the National College Students Innovation Experiment Program (No. 201610699287)
文摘A series of experimental studies was carried out to investigate the influences of pretorsion on microstructure evolution, mechanical properties, and fracture appearance of pure titanium subjected to subsequent tension deformation. An introduction of pre-torsion strain can improve the materials＇ mechanical properties through micro hardness evaluation. That is, the micro hardness of tensile samples with pre-torsion deformation is much higher than that of samples processed by single torsion or tension. It can be seen from the microstructure that pre-torsion deformation can be used to refine grains better and control grains＇ morphology by combining subsequent tension. The results indicate that the grains are refined most evidently for tensile samples with 2 turn pre-torsion deformation. Moreover, fracture analysis indicates that tensile samples with pre-torsion strain can present good comprehensive performance. In conclusion, pre-torsion deformation plays an important role in improving comprehensive performance and controlling microstructure evolution on pure titanium subjected to later tension deformation.
基金supported by the Joint Funds of The National Natural Science Foundation of China(Grant No.U19B6003-05)the National Key Research and Development Program of China(No.2019YFA0708302)+2 种基金the National Science Fund for Distinguished Young Scholars(Grant No.51725404)the Beijing Outstanding Young Scientist Program(Grant No.BJJWZYJH01201911414038)the Strategic Cooperation Technology Projects of CNPC and CUPB(Grant No.ZLZX2020-01).
文摘The Stinger PDC cutter has high rock-breaking efficiency and excellent impact and wear resistance, which can significantly increase the rate of penetration (ROP) and extend PDC bit life for drilling hard and abrasive formation. The knowledge of force response and mechanical specific energy (MSE) for the Stinger PDC cutter is of great importance for improving the cutter's performance and optimizing the hybrid PDC bit design. In this paper, 87 single cutter tests were conducted on the granite. A new method for precisely obtaining the rock broken volume was proposed. The influences of cutting depth, cutting angle, and cutting speed on cutting force and MSE were analyzed. Besides, a phenomenological cutting force model of the Stinger PDC cutter was established by regression of experimental data. Moreover, the surface topography and fracture morphology of the cutting groove and large size cuttings were measured by a 3D profilometer and a scanning electron microscope (SEM). Finally, the rock-breaking mechanism of the Stinger PDC cutter was illustrated. The results indicated that the cutting depth has the greatest influence on the cutting force and MSE, while the cutting speed has no obvious effects, especially at low cutting speeds. As the increase of cutting depth, the cutting force increases linearly, and MSE reduces with a quadratic polynomial relationship. When the cutting angle raises from 10° to 30°, the cutting force increases linearly, and the MSE firstly decreases and then increases. The optimal cutting angle for breaking rock is approximately 20°. The Stinger PDC cutter breaks granite mainly by high concentrated point loading and tensile failure, which can observably improve the rock breaking efficiency. The key findings of this work will help to reveal the rock-breaking mechanisms and optimize the cutter arrangement for the Stinger PDC cutter.
基金supported by the National Natural Science Foundation of China[Grant No.42041004]the“Innovation Star”Project for Outstanding Postgraduates of Gansu Province[Grant No.2022CXZX-107]the Central Universities[Grant No.lzujbky-2019-kb30].
基金supported by the National Natural Science Foundation of China(81872995).
文摘Objective:To investigate the effect of Guangdong Shenqu(GSQ)on intestinal flora structure in mice with food stagnation through 16S rDNA sequencing.Methods: Mice were randomly assigned to control,model,GSQ low-dose(GSQL),GSQ medium-dose(GSQM),GSQ high-dose(GSQH),and lacidophilin tablets(LAB)groups,with each group containing 10 mice.A food stagnation and internal heat mouse model was established through intragastric administration of a mixture of beeswax and olive oil(1:15).The control group was administered normal saline,and the model group was administered beeswax and olive oil to maintain a state.The GSQL(2 g/kg),GSQM(4 g/kg),GSQH(8 g/kg),and LAB groups(0.625 g/kg)were administered corresponding drugs for 5 d.After administration,16S rDNA sequencing was performed to assess gut microbiota in mouse fecal samples.Results: The model group exhibited significant intestinal flora changes.Following GSQ administration,the abundance and diversity index of the intestinal flora increased significantly,the number of bacterial species was regulated,andαandβdiversity were improved.GSQ administration increased the abundance of probiotics,including Clostridia,Lachnospirales,and Lactobacillus,whereas the abundance of conditional pathogenic bacteria,such as Allobaculum,Erysipelotrichaceae,and Bacteroides decreased.Functional prediction analysis indicated that the pathogenesis of food stagnation and GSQ intervention were primarily associated with carbohydrate,lipid,and amino acid metabolism,among other metabolic pathways.Conclusion: The digestive mechanism of GSQ may be attributed to its role in restoring diversity and abundance within the intestinal flora,thereby improving the composition and structure of the intestinal flora in mice and subsequently influencing the regulation of metabolic pathways.
文摘In this paper, a coordinate transformation method (CTM) is employed to numerically solve the Poisson–Nernst–Planck (PNP) equation and Navier–Stokes (NS) equations for studying the traveling-wave electroosmotic flow (TWEF) in a two-dimensional microchannel. Numerical solutions indicate that the numerical solutions of TWEF with and without the coordinate transformation are in good agreement, while CTM effectively improves stability and convergence rate of the numerical solution, and saves computational cost. It is found that the averaged flow velocity of TWEF in a micro-channel strongly depends on frequency of the electric field. Flow rate achieves a maximum around the charge frequency of the electric double layer. The approximate solutions of TWEF with slip boundary conditions are also presented for comparison. It is shown that the NS solution with slip boundary conditions agree well with those of complete PNP-NS equations in the cases of small ratios of Electric double layer(EDL) thickness to channel depth(λD/H). The NS solution with slip boundary conditions over-estimates the electroosmotic flow velocity as this ratio(λD/H) is large.
基金partly supported by the National Natural Science Foundation of China(No.51972108)Distinguished Young Scientists of Hunan Province(No.2022JJ10024)+1 种基金Natural Science Foundation of Hunan Province(No.2021JJ30216)Key Projects of Hunan Provincial Education Department(No.22A0412)。
文摘In the face of multiple challenges brought by the changes of global climate and environment,developing clean energy and updating green energy storage equipment are important ways to achieve carbon peak and carbon neutrality.Aqueous batteries have become a research hotspot due to their advantages of using the multivalent charge carrier,high ionic conductivity,environmental friendliness and cost effectiveness.In this work,the Cu_(2)Se@C(Cu_(2)Se coated on carbon clothes)thin film with a three-dimensional braided structure is fabricated by a simple electrochemical deposition method for Cu^(2+)storage for the first time.Compared with the commercial Cu_(2)Se powder,the well-designed Cu_(2)Se@C film shows enhanced specific capacity(640 mAh/g at 0.5 A/g)and rate performance(542 mAh/g at 5 A/g)as well as superior cycling stability(82.7%capacity retention after 1000 cycles at 1 A/g).The Cu^(2+)storage mechanism of the Cu_(2)Se@C electrode is based on a reversible phase transition process of Cu_(2)Se←→Cu_(2-x)Se←→CuSe←→CuSe_(2).In kinetic characteristic analysis,the Cu_(2)Se@C electrode demonstrates faster Cu^(2+)diffusion in discharge process than charge process resulting from the phase transition and the variation of interplanar spacing.This work highlights a facile one-piece design strategy and opens a new gateway for the exploration of advanced aqueous energy storage systems.
文摘Introduction: Langerhans cell histiocytosis (LCH) is a group of idiopathic disorders characterized by the proliferation of specialized bone marrow-derived Langerhans cells (LCs) and mature eosinophils, resulting in solitary or few, indolent and chronic, lesions of bone or other organs called eosinophilic granulomas. Calvarial LCH is quite rare and an underappreciated differential etiology of skull lesions. We present a most unusual case of a young child with hyperacutely symptomatic langerhans histiocytosis of the skull. Method: A 7-year-old male presented with a history of increasing (progressive) frontal headaches of 8 days duration, unaccompanied by associated nausea, vomiting, or diplopia. His only additional complaint was a hard bump on his forehead. MRI and CT done in the ER identified a right fronto-parietal lesion with associated skull erosion. Nuclear medicine and SPECT studies confirmed an erosive skull lesion without significant metabolic activity. A right frontal craniectomy and excision was performed. Results: A soft, rubbery well-circumcised mass coming from the diploic layer of the skull with involvement of bone was identified. The mass had eroded both the outer and inner table of the skull, and the involved area of the right frontal bone was resected. Intra-operative histo-pathologic analysis of the lesion revealed Langerhans cell histiocytosis without involvement of the dura. The patient experienced no neurological worsening as a result of the resection. He was discharged home in stable condition. Conclusion: LCH lesions of the skull are common findings, however, this focal hyperacute symptomatic presentation is most rare and should not deter us from anticipating an erosive bony tumor and planning timely surgical management.
