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Mycobacterium smegmatis enhances shikonin-induced immunogenic cell death—an efficient in situ tumor vaccine strategy 被引量:1
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作者 Zhaoye Qian Zhe Zhang +4 位作者 Lanqi Cen Yaohua Ke Jie Shao Manman Tian Baorui Liu 《Journal of Biomedical Research》 CAS CSCD 2024年第4期369-381,共13页
Tumor vaccines are a promising avenue in cancer immunotherapy.Despite the progress in targeting specific immune epitopes,tumor cells lacking these epitopes can evade the treatment.Here,we aimed to construct an efficie... Tumor vaccines are a promising avenue in cancer immunotherapy.Despite the progress in targeting specific immune epitopes,tumor cells lacking these epitopes can evade the treatment.Here,we aimed to construct an efficient in situ tumor vaccine called Vac-SM,utilizing shikonin(SKN)to induce immunogenic cell death(ICD)and Mycobacterium smegmatis as an immune adjuvant to enhance in situ tumor vaccine efficacy.SKN showed a dose-dependent and time-dependent cytotoxic effect on the tumor cell line and induced ICD in tumor cells as evidenced by the CCK-8 assay and the detection of the expression of relevant indicators,respectively.Compared with the control group,the in situ Vac-SM injection in mouse subcutaneous metastatic tumors significantly inhibited tumor growth and distant tumor metastasis,while also improving survival rates.Mycobacterium smegmatis effectively induced maturation and activation of bone marrow-derived dendritic cells(DCs),and in vivo tumor-draining lymph nodes showed an increased maturation of DCs and a higher proportion of effector memory T-cell subsets with the Vac-SM treatment,based on flow cytometry analysis results.Collectively,the Vac-SM vaccine effectively induces ICD,improves antigen presentation by DCs,activates a specific systemic antitumor T-cell immune response,exhibits a favorable safety profile,and holds the promise for clinical translation for local tumor immunotherapy. 展开更多
关键词 mycobacterium SMEGMATIS SHIKONIN IMMUNOGENIC cell death tumor vaccines IMMUNOGENICITY CYTOTOXICITY
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Contribution to the Study of Resistance to Anti-Tuberculosis Drugs in the Mycobacterium tuberculosis Complex Isolated at the National Laboratory of Clinical Biology and Public Health in Bangui in the Central African Republic in 2022: Case of Rifampicin
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作者 Clotaire Donatien Rafaï Max Namzeka +7 位作者 Ernest Lango-Yaya Romaric Oscar Tibet Kada Oscar Senzongo Ndimakamoko Serge Henri Gbazi Le Bon Bondom Christian Maucler Pamatika Boniface Koffi Alain Le Faou 《Journal of Tuberculosis Research》 2023年第4期162-172,共11页
Microscopy-positive and drug-resistant pulmonary tuberculosis (MPT+) is one of the most feared diseases due to the cost of its management and the associated mortality. The GeneXpert, a new molecular test, is in greate... Microscopy-positive and drug-resistant pulmonary tuberculosis (MPT+) is one of the most feared diseases due to the cost of its management and the associated mortality. The GeneXpert, a new molecular test, is in greater demand for the diagnosis of MPT+ resistance cases. The application of GeneXpert to new cases of MPT+ is not effective in the country’s TB screening centres. The objective of this study is to assess the contribution of GeneXpert to the determination of MPT+ resistance cases in Bangui. The study was cross-sectional and covered the period from February to July 2022. The diagnosis of tuberculosis was first performed by microscopy with Ziehl Neelsen hot stain. The GeneXpert was then used to test for resistance in the sputum of all patients with positive microscopy. The collected data was entered into Excel 2013 and analysed with Epi Info 3.3.7. We analysed data from 755 patients, 80 of whom had resistance. The 80 patients ranged in age from 6 to 68 years (mean age = 35 years). The prevalence of resistant TB was 10.60% (80/755). Primary resistance accounted for 73.75% and secondary resistance for 26.25%. The age group 20 - 39 years (57.50%), male (72.50%), 8th district (17.50%), people living in couples (53.75%), farmers (13.75%) were the socio-demographic characteristics most affected by resistance. Treatment failure (13.75%), relapses (13.75%), the notion of contagion (28.75%), a history of smoking (40%) and alcohol (61.25%) were the clinical antecedents reported by the patients. Treatment failure and relapse were the variables associated with the occurrence of resistant PMT+ (p 0.05). A considerable proportion of the overall Mycobacterium tuberculosis resistance to anti-tuberculosis drugs (10.60%) was identified by GeneXpert. Treatment failure and relapse were the factors associated with the risk of resistance. 展开更多
关键词 GeneXpert RESISTANCE mycobacterium tuberculosis Bangui
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Emulsifying property,antioxidant activity,and bitterness of soybean protein isolate hydrolysate obtained by Corolase PP under high hydrostatic pressure 被引量:1
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作者 Haining Guan Chunmei Feng +3 位作者 Min Ren Xiaojun Xu Dengyong Liu Xiaoqin Diao 《Food Science and Human Wellness》 SCIE CSCD 2024年第3期1271-1278,共8页
Enzymatic hydrolysis of proteins can enhance their emulsifying properties and antioxidant activities.However,the problem related to the hydrolysis of proteins was the generation of the bitter taste.Recently,high hydro... Enzymatic hydrolysis of proteins can enhance their emulsifying properties and antioxidant activities.However,the problem related to the hydrolysis of proteins was the generation of the bitter taste.Recently,high hydrostatic pressure(HHP)treatment has attracted much interest and has been used in several studies on protein modification.Hence,the study aimed to investigate the effects of enzymatic hydrolysis by Corolase PP under different pressure treatments(0.1,100,200,and 300 MPa for 1-5 h at 50℃)on the emulsifying property,antioxidant activity,and bitterness of soybean protein isolate hydrolysate(SPIH).As observed,the hydrolysate obtained at 200 MPa for 4 h had the highest emulsifying activity index(47.49 m^(2)/g)and emulsifying stability index(92.98%),and it had higher antioxidant activities(44.77%DPPH free radical scavenging activity,31.12%superoxide anion radical scavenging activity,and 61.50%copper ion chelating activity).At the same time,the enhancement of emulsion stability was related to the increase of zeta potential and the decrease of mean particle size.In addition,the hydrolysate obtained at 200 MPa for 4 h had a lower bitterness value and showed better palatability.This study has a broad application prospect in developing food ingredients and healthy foods. 展开更多
关键词 Soybean protein isolate High hydrostatic pressure EMULSIFICATION ANTIOXIDANT Bitter taste
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Seismic response of a mid-story isolated structure considering SSI in mountainous areas under long-period earthquakes 被引量:1
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作者 Wan Feng Qin Shengwu +7 位作者 Liu Dewen Zhao Tiange Zheng Yanping Shan Hang Li Zhiang Peng Fusong Xu Jingran Lei Min 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2024年第1期151-161,共11页
At present,there is not much research on mid-story isolated structures in mountainous areas.In this study,a model of a mid-story isolated structure considering soil-structure interaction(SSI)in mountainous areas is es... At present,there is not much research on mid-story isolated structures in mountainous areas.In this study,a model of a mid-story isolated structure considering soil-structure interaction(SSI)in mountainous areas is established along with a model that does not consider SSI.Eight long-period earthquake waves and two ordinary earthquake waves are selected as inputs for the dynamic time history analysis of the structure.The results show that the seismic response of a mid-story isolated structure considering SSI in mountainous areas can be amplified when compared with a structure that does not consider SSI.The structure response under long-period earthquakes is larger than that of ordinary earthquakes.The structure response under far-field harmonic-like earthquakes is larger than that of near-fault pulse-type earthquakes.The structure response under near-fault pulse-type earthquakes is larger than that of far-field non-harmonic earthquakes.When subjected to long-period earthquakes,the displacement of the isolated bearings exceeded the limit value,which led to instability and overturning of the structure.The structure with dampers in the isolated story could adequately control the nonlinear response of the structure,effectively reduce the displacement of the isolated bearings,and provide a convenient,efficient and economic method not only for new construction but also to retrofit existing structures. 展开更多
关键词 SSI in mountainous areas long-period earthquakes mid-story isolated structure structural dynamic analysis
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Molecular Identification of Mycobacterium Strains Responsible of Bovine Tuberculosis Cases in Bobo-Dioulasso Slaughterhouse, Burkina Faso
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作者 Mariétou Konate Aminata Fofana# +2 位作者 Yacouba Kouadima Aboubacar Sidiki Ouattara Adama Sanou 《Advances in Microbiology》 CAS 2024年第2期105-114,共10页
Bovine tuberculosis (bTB) is an endemic zoonosis significantly affects animal health in Burkina Faso. The primary causative agent is Mycobacterium tuberculosis (M. tuberculosis) complex, mainly M. bovis. Cattle are co... Bovine tuberculosis (bTB) is an endemic zoonosis significantly affects animal health in Burkina Faso. The primary causative agent is Mycobacterium tuberculosis (M. tuberculosis) complex, mainly M. bovis. Cattle are considered as natural reservoir of M. bovis. However, in Burkina Faso, the circulation of these strains remains poorly understood and documented. This study aimed to identify and characterize Mycobacterium strains from suspected carcasses during routine meat inspection at Bobo-Dioulasso refrigerated slaughterhouse. A prospective cross-sectional study was conducted from January 2021 to December 2022 on cases of seizures linked to suspected bovine tuberculosis. Microbiological and molecular analyzes were used for mycobacterial strain isolation and characterization. Out of 50 samples, 24% tested positive by microscopy and 12% by culture. Molecular analysis identified 6 strains of Mycobacteria, exclusively Mycobacterium bovis specifically the subspecies bovis (Mycobacterium bovis subsp bovis). In conclusion, M. bovis subsp bovis is the primary agent responsible for bovine tuberculosis in Bobo-Dioulasso. Continuous monitoring of mycobacterial strains is therefore necessary for the effective control of this pathology in the local cattle population. 展开更多
关键词 Bovine Tuberculosis mycobacterium bovis Molecular Identification Cattle Population Burkina Faso
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Epidemiology and Clinical Features of Mycobacterium avium Complex Pulmonary Disease in a Brazilian Amazon Cohort
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作者 Jose Tadeu Colares Monteiro Adriana Rodrigues Barretto +9 位作者 Ruan Seguin Azevedo Quaresma Bianca Miranda Gouveia Ismari Perini Furlaneto Victória Menezes da Costa Yan Corrêa Rodrigues Layana Rufino Ribeiro Ricardo J. de Paula Souza e Guimarães Alex Brito Souza Ana Roberta Fusco da Costa Karla Valéria Batista Lima 《Advances in Microbiology》 CAS 2024年第6期287-302,共16页
The incidence of Mycobacterium avium complex pulmonary disease (MACPD) has been globally increasing. The present study aims to provide a comprehensive analysis of clinical characteristics and treatment response among ... The incidence of Mycobacterium avium complex pulmonary disease (MACPD) has been globally increasing. The present study aims to provide a comprehensive analysis of clinical characteristics and treatment response among patients in the Amazon region of Brazil and conduct a retrospective cohort study at a prominent referral hospital in the State of Par, Brazil, from 2012 to 2020. The M. avium group represented 58.9% of cases, followed by M. intracellulare (35.7%), M. colombiense (3.6%), and M. chimaera (1.8%). The majority of patients (73.2%) were female and with an average age of 63 years. Primary clinical manifestations included persistent cough and sputum production. The Charlson comorbidity index (CCI) averaged 2.47, with 36.3% of patients having a CCI score equal to higher than 3. Notably, over 70% of patients had received treatment for pulmonary tuberculosis before initiating treatment for MAC infection. The fibrocavitary radiologic form was the most prevalent (55.4%), frequently exhibiting a bilateral distribution (53.6%). Antimicrobial susceptibility revealed a significant prevalence of MAC resistance to drugs in the therapeutic regimen. Despite this, most of the patients experienced clinical improvement (50%). In conclusion, this study highlights a higher prevalence of MAC infections among middle-aged women, with a history of pulmonary tuberculosis treatment and presenting the fibrocavitary radiological form was predominant. 展开更多
关键词 MACDP Nontuberculous Mycobacteria mycobacterium avium Lung Disease
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Inferring Mycobacterium Tuberculosis Drug Resistance and Transmission using Whole-genome Sequencing in a High TB-burden Setting in China
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作者 FAN Yu Feng LIU Dong Xin +11 位作者 CHEN Yi Wang OU Xi Chao MAO Qi Zhi YANG Ting Ting WANG Xi Jiang HE Wen Cong ZHAO Bing LIU Zhen Jiang ABULIMITI Maiweilanjiang AIHEMUTI Maimaitiaili GAO Qian ZHAO Yan Lin 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2024年第2期157-169,共13页
Objective China is among the 30 countries with a high burden of tuberculosis(TB)worldwide,and TB remains a public health concern.Kashgar Prefecture in the southern Xinjiang Autonomous Region is considered as one of th... Objective China is among the 30 countries with a high burden of tuberculosis(TB)worldwide,and TB remains a public health concern.Kashgar Prefecture in the southern Xinjiang Autonomous Region is considered as one of the highest TB burden regions in China.However,molecular epidemiological studies of Kashgar are lacking.Methods A population-based retrospective study was conducted using whole-genome sequencing(WGS)to determine the characteristics of drug resistance and the transmission patterns.Results A total of 1,668 isolates collected in 2020 were classified into lineages 2(46.0%),3(27.5%),and 4(26.5%).The drug resistance rates revealed by WGS showed that the top three drugs in terms of the resistance rate were isoniazid(7.4%,124/1,668),streptomycin(6.0%,100/1,668),and rifampicin(3.3%,55/1,668).The rate of rifampicin resistance was 1.8%(23/1,290)in the new cases and 9.4%(32/340)in the previously treated cases.Known resistance mutations were detected more frequently in lineage 2 strains than in lineage 3 or 4 strains,respectively:18.6%vs.8.7 or 9%,P<0.001.The estimated proportion of recent transmissions was 25.9%(432/1,668).Multivariate logistic analyses indicated that sex,age,occupation,lineage,and drug resistance were the risk factors for recent transmission.Despite the low rate of drug resistance,drug-resistant strains had a higher risk of recent transmission than the susceptible strains(adjusted odds ratio,1.414;95%CI,1.023–1.954;P=0.036).Among all patients with drug-resistant tuberculosis(DR-TB),78.4%(171/218)were attributed to the transmission of DR-TB strains.Conclusion Our results suggest that drug-resistant strains are more transmissible than susceptible strains and that transmission is the major driving force of the current DR-TB epidemic in Kashgar. 展开更多
关键词 mycobacterium tuberculosis Whole-genome sequencing(WGS) Transmission Drug resistance XINJIANG
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Tuberculosis in the Carcinal Environment in Chad Due to the Mycobacterium Tuberculosis Circulante Complex
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作者 Ahmat Idriss Ahmat Mahamat Tahir Ngaré Hassan +4 位作者 Ngandolo Bongo Nare Richard Mahamat Adanao Adoudou Mbah Ntepe Leonel Javeres Hamidou Yacoubou Ali Mahamat Moussa 《Journal of Biosciences and Medicines》 2024年第2期214-224,共11页
Tuberculosis (TB) is a serious infectious disease and its control is considered a challenge, particularly among vulnerable populations such as prisoners. The prevalence of TB in prisons is an alarming public health pr... Tuberculosis (TB) is a serious infectious disease and its control is considered a challenge, particularly among vulnerable populations such as prisoners. The prevalence of TB in prisons is an alarming public health problem in many countries. The aim of this study is to describe the epidemiology of tuberculosis and the strategies for controlling this disease in the Chadian prison population. During the course of our study, the prevalence of tuberculosis in prisons was 9.64%. The age group between 55 years and over (43.33%) was the most represented in this study, and all patients were men with a frequency of 62.66%. The cross-tabulation of Culture_7H9G and Culture_7H9P showed that out of our total positive sample, we found a total of 87 positive strains and 63 negative strains. Our study shows that it is essential to know the prevalence of tuberculosis in all the country’s prisons. Indeed, this can serve as an indication of the need for action in prisons to reduce TB rates, in particular by improving the structure of prison environments, diagnosing new cases quickly and accurately, identifying drug-resistant strains and implementing effective, direct treatment observed in people with tuberculosis. 展开更多
关键词 mycobacterium PRISON Tuberculosis and Chad
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A viscoelastic metamaterial beam for integrated vibration isolation and energy harvesting
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作者 Long ZHAO Zeqi LU +1 位作者 Hu DING Liqun CHEN 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第7期1243-1260,共18页
Locally resonant metamaterials have low-frequency band gaps and the capability of converging vibratory energy in the band gaps at resonant cells.It has been demonstrated by several researchers that the dissipatioin of... Locally resonant metamaterials have low-frequency band gaps and the capability of converging vibratory energy in the band gaps at resonant cells.It has been demonstrated by several researchers that the dissipatioin of vibratory energy within the band gap can be improved by using viscoelastic materials.This paper designs an integrated viscoelastic metamaterial for energy harvesting and vibration isolation.The viscoelastic metamaterial is achieved by a viscoelastic beam periodically arrayed with spatial ball-pendulum nonlinear energy harvesters.The nonlinear resonator with an energy harvesting function is achieved by placing a free-rolling magnetic ball in a spherical cavity with an additional induction coil.The dynamic equations of viscoelastic metamaterials under transverse excitation are established,and the energy harvesting and vibration isolation characteristics within the dispersion relation of viscoelastic metamaterials are analyzed.The results show that the vibrations of the main body of the viscoelastic metamaterial beam are significantly suppressed in the frequency range of the local resonance band gap.At the same time,the elastic waves are limited in the nonlinear resonator with an energy harvesting function,which improves the energy output.Finally,an experimental platform of viscoelastic metamaterial vibration is established for validation purposes. 展开更多
关键词 viscoelastic metamaterial nonlinear vibration vibration isolation energy harvesting
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Sedimentary build-ups of pre-salt isolated carbonate platforms and formation of deep-water giant oil fields in Santos Basin,Brazil
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作者 DOU Lirong WEN Zhixin +7 位作者 WANG Zhaoming HE Zhengjun SONG Chengpeng CHEN Ruiyin YANG Xiaofa LIU Xiaobing LIU Zuodong CHEN Yanyan 《Petroleum Exploration and Development》 SCIE 2024年第4期949-962,共14页
In response to the problems of unclear distribution of deep-water pre-salt carbonate reservoirs and formation conditions of large oil fields in the Santos passive continental margin basin,based on comprehensive utiliz... In response to the problems of unclear distribution of deep-water pre-salt carbonate reservoirs and formation conditions of large oil fields in the Santos passive continental margin basin,based on comprehensive utilization of geological,seismic,and core data,and reconstruction of Early Cretaceous prototype basin and lithofacies paleogeography,it is proposed for the first time that the construction of pre-salt carbonate build-ups was controlled by two types of isolated platforms:inter-depression fault-uplift and intra-depression fault-high.The inter-depression fault-uplift isolated platforms are distributed on the present-day pre-salt uplifted zones between depressions,and are built on half-and fault-horst blocks that were inherited and developed in the early intra-continental and inter-continental rift stages.The late intra-continental rift coquinas of the ITP Formation and the early inter-continental rift microbial limestones of the BVE Formation are continuously constructed;intra-depression fault-high isolated platforms are distributed in the current pre-salt depression zones,built on the uplifted zones formed by volcanic rock build-ups in the early prototype stage of intra-continental rifts,and only the BVE microbial limestones are developed.Both types of limestones formed into mound-shoal bodies,that have the characteristics of large reservoir thickness and good physical properties.Based on the dissection of large pre-salt oil fields discovered in the Santos Basin,it has been found that both types of platforms could form large-scale combined structural-stratigraphic traps,surrounded by high-quality lacustrine and lagoon source rocks at the periphery,and efficiently sealed by thick high-quality evaporite rocks above,forming the optimal combination of source,reservoir and cap in the form of“lower generation,middle storage,and upper cap”,with a high degree of oil and gas enrichment.It has been found that the large oil fields are all bottom water massive oil fields with a unified pressure system,and they are all filled to the spill-point.The future exploration is recommended to focus on the inter-depression fault-uplift isolated platforms in the western uplift zone and the southern section of eastern uplift zones,as well as intra-depression fault-high isolated platforms in the central depression zone.The result not only provides an important basis for the advanced selection of potential play fairways,bidding of new blocks,and deployment of awarded exploration blocks in the Santos Basin,but also provides a reference for the global selection of deep-water exploration blocks in passive continental margin basins. 展开更多
关键词 Santos Basin passive continental marginal basin deep water inter-depression fault-uplift isolated carbonate platform intra-depression fault-high carbonate isolated platform giant oil fields
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Early Prosthetic Valve Endocarditis with Mycobacterium Tuberculosis after Mitral Valve Replacement: A Case Report
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作者 Papa Amath Diagne Mory Camara +12 位作者 Papa Ousmane Ba Momar Sokhna Diop Moussa Samba Abdou Lahad Mbengue Jean Claude Ndiogou Dione Myriam Bizrane Marième Soda Mbaye Moussa Seck Diop Toudiani Malam Kaka Papa Salmane Ba Papa Adama Dieng Amadou Gabriel Ciss Assane Ndiaye 《World Journal of Cardiovascular Surgery》 2024年第3期33-40,共8页
Background: Tuberculous endocarditis is a rare but serious complication of heart valve replacement surgery. We report the case of a 24-year-old patient, who presented with tuberculous endocarditis after mechanical mit... Background: Tuberculous endocarditis is a rare but serious complication of heart valve replacement surgery. We report the case of a 24-year-old patient, who presented with tuberculous endocarditis after mechanical mitral valve replacement, with a favorable clinical course following anti-tuberculosis treatment. Case Presentation: We report a 24-year-old male patient, admitted to the cardiac surgery department of the Fann Hospital (Dakar, Senegal), for the management of severe mixed (rheumatic and endocarditic) mitral insufficiency with associated tricuspid insufficiency. He had a history of recurrent angina and polyarthralgia in childhood, was hospitalized several times for refractory global cardiac decompensation, and for a suspected infective endocarditis a month before his admission. On admission, the clinical examination revealed signs suggestive of mitral and tricuspid insufficiency. Transthoracic echocardiography revealed severe post-endocarditic mitral insufficiency with A3 amputation, highly mobile 15 mm vegetations on the free edge of the large valve, moderate tricuspid insufficiency, and severe pulmonary artery hypertension. Mechanical mitral valve replacement and tricuspid valve annuloplasty using autologous pericardial strip were performed via median sternotomy. After ten days, the patient presented with global cardiac decompensation associated with a clinico-biological infectious syndrome, and tans-oesophageal echography revealed an abscess at the sinotubular junction, communicating with the aorta. A thoraco-abdomino-pelvic CT scan was done, which revealed a bilateral alveolar-interstitial syndrome with mediastinal lymphadenopathy. Anti-tuberculosis treatment with RHZE was initiated for 06 months. The clinical course was favorable. Conclusion: Tuberculous endocarditis in prostheses is a serious complication of heart valve replacement surgery, which may evolve favorably under medical treatment. 展开更多
关键词 Tuberculous Endocarditis Prosthetic Valve Endocarditis mycobacterium Tuberculosis
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Dynamic analysis of a novel multilink-spring mechanism for vibration isolation and energy harvesting
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作者 谢佳衡 杨涛 唐介 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第5期366-379,共14页
Due to technical limitations,existing vibration isolation and energy harvesting(VIEH)devices have poor performance at low frequency.This paper proposes a new multilink-spring mechanism(MLSM)that can be used to solve t... Due to technical limitations,existing vibration isolation and energy harvesting(VIEH)devices have poor performance at low frequency.This paper proposes a new multilink-spring mechanism(MLSM)that can be used to solve this problem.The VIEH performance of the MLSM under harmonic excitation and Gaussian white noise was analyzed.It was found that the MLSM has good vibration isolation performance for low-frequency isolation and the frequency band can be widened by adjusting parameters to achieve a higher energy harvesting power.By comparison with two special cases,the results show that the MLSM is basically the same as the other two oscillators in terms of vibration isolation but has better energy harvesting performance under multistable characteristics.The MLSM is expected to reduce the impact of vibration on high-precision sensitive equipment in some special sites such as subways and mines,and at the same time supply power to structural health monitoring devices. 展开更多
关键词 multilink-spring mechanism nonlinear dynamics vibration isolation energy harvester
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A low-frequency and broadband wave-insulating vibration isolator based on plate-shaped metastructures
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作者 Wei WEI Feng GUAN Xin FANG 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第7期1171-1188,共18页
A metamaterial vibration isolator,termed as wave-insulating isolator,is proposed,which preserves enough load-bearing capability and offers ultra-low and broad bandgaps for greatly enhanced wave insulation.It consists ... A metamaterial vibration isolator,termed as wave-insulating isolator,is proposed,which preserves enough load-bearing capability and offers ultra-low and broad bandgaps for greatly enhanced wave insulation.It consists of plate-shaped metacells,whose symmetric and antisymmetric local resonant modes offer several low and broad mode bandgaps although the complete bandgap remains high and narrow.The bandgap mechanisms,vibration isolation properties,effects of key parameters,and robustness to complex conditions are clarified.As experimentally demonstrated,the wave-insulating isolator can improve the vibration insulation in the ranges of[50 Hz,180 Hz]and[260 Hz,400 Hz]by 15 dB and 25 dB,respectively,in contrast to the conventional isolator with the same first resonant frequency. 展开更多
关键词 metamaterial and metastructure vibration isolation bandgap wave insulation PLATE
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Prediction of Damping Capacity Demand in Seismic Base Isolators via Machine Learning
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作者 Ayla Ocak Umit Isıkdag +3 位作者 Gebrail Bekdas Sinan Melih Nigdeli Sanghun Kim ZongWoo Geem 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第3期2899-2924,共26页
Base isolators used in buildings provide both a good acceleration reduction and structural vibration control structures.The base isolators may lose their damping capacity over time due to environmental or dynamic effe... Base isolators used in buildings provide both a good acceleration reduction and structural vibration control structures.The base isolators may lose their damping capacity over time due to environmental or dynamic effects.This deterioration of them requires the determination of the maintenance and repair needs and is important for the long-termisolator life.In this study,an artificial intelligence prediction model has been developed to determine the damage and maintenance-repair requirements of isolators as a result of environmental effects and dynamic factors over time.With the developed model,the required damping capacity of the isolator structure was estimated and compared with the previously placed isolator capacity,and the decrease in the damping property was tried to be determined.For this purpose,a data set was created by collecting the behavior of structures with single degrees of freedom(SDOF),different stiffness,damping ratio and natural period isolated from the foundation under far fault earthquakes.The data is divided into 5 different damping classes varying between 10%and 50%.Machine learning model was trained in damping classes with the data on the structure’s response to random seismic vibrations.As a result of the isolator behavior under randomly selected earthquakes,the recorded motion and structural acceleration of the structure against any seismic vibration were examined,and the decrease in the damping capacity was estimated on a class basis.The performance loss of the isolators,which are separated according to their damping properties,has been tried to be determined,and the reductions in the amounts to be taken into account have been determined by class.In the developed prediction model,using various supervised machine learning classification algorithms,the classification algorithm providing the highest precision for the model has been decided.When the results are examined,it has been determined that the damping of the isolator structure with the machine learning method is predicted successfully at a level exceeding 96%,and it is an effective method in deciding whether there is a decrease in the damping capacity. 展开更多
关键词 Vibration control base isolation machine learning damping capacity
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Multi-layer quasi-zero-stiffness meta-structure for high-efficiency vibration isolation at low frequency
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作者 Jiahao ZHOU Jiaxi ZHOU +3 位作者 Hongbin PAN Kai WANG Changqi CAI Guilin WEN 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第7期1189-1208,共20页
An easily stackable multi-layer quasi-zero-stiffness(ML-QZS)meta-structure is proposed to achieve highly efficient vibration isolation performance at low frequency.First,the distributed shape optimization method is us... An easily stackable multi-layer quasi-zero-stiffness(ML-QZS)meta-structure is proposed to achieve highly efficient vibration isolation performance at low frequency.First,the distributed shape optimization method is used to design the unit cel,i.e.,the single-layer QZS(SL-QZS)meta-structure.Second,the stiffness feature of the unit cell is investigated and verified through static experiments.Third,the unit cells are stacked one by one along the direction of vibration isolation,and thus the ML-QZS meta-structure is constructed.Fourth,the dynamic modeling of the ML-QZS vibration isolation metastructure is conducted,and the dynamic responses are obtained from the equations of motion,and verified by finite element(FE)simulations.Finally,a prototype of the ML-QZS vibration isolation meta-structure is fabricated by additive manufacturing,and the vibration isolation performance is evaluated experimentally.The results show that the vibration isolation performance substantially enhances when the number of unit cells increases.More importantly,the ML-QZS meta-structure can be easily extended in the direction of vibration isolation when the unit cells are properly stacked.Hence,the ML-FQZS vibration isolation meta-structure should be a fascinating solution for highly efficient vibration isolation performance at low frequency. 展开更多
关键词 quasi-zero stiffness(QZS) meta-structure high efficiency low frequency vibration isolation
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A vibration isolator with a controllable quasi-zero stiffness region based on nonlinear force design
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作者 Xinyu LIAN Bing LIU +1 位作者 Huaxia DENG Xinglong GONG 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第8期1279-1294,共16页
To achieve stability optimization in low-frequency vibration control for precision instruments,this paper presents a quasi-zero stiffness(QZS)vibration isolator with adjustable nonlinear stiffness.Additionally,the str... To achieve stability optimization in low-frequency vibration control for precision instruments,this paper presents a quasi-zero stiffness(QZS)vibration isolator with adjustable nonlinear stiffness.Additionally,the stress-magnetism coupling model is established through meticulous theoretical derivation.The controllable QZS interval is constructed via parameter design and magnetic control,effectively segregating the high static stiffness bearing section from the QZS vibration isolation section.Furthermore,a displacement control scheme utilizing a magnetic force is proposed to regulate entry into the QZS working range for the vibration isolation platform.Experimental results demonstrate that the operation within this QZS region reduces the peak-to-peak acceleration signal by approximately 66.7%compared with the operation outside this region,thereby significantly improving the low frequency performance of the QZS vibration isolator. 展开更多
关键词 low frequency NONLINEAR vibration isolator quasi-zero stiffness(QzS)
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Effects of galactooligosaccharide glycation on the functional properties of soy protein isolate and its application in noodles
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作者 Meiyue Wang Guanhao Bu +3 位作者 Yufei Xing Mengke Ren Yang Wang Yijing Xie 《Grain & Oil Science and Technology》 CAS 2024年第3期159-167,共9页
Soybean protein has high nutritional value, but its functional properties are easily affected by external factors,which limits its application in food industry. In the study, soybean protein isolate(SPI) was modified ... Soybean protein has high nutritional value, but its functional properties are easily affected by external factors,which limits its application in food industry. In the study, soybean protein isolate(SPI) was modified by dry heat glycation of galactooligosaccharides(GOS). The gel properties, antioxidant properties and structural changes of SPI-GOS conjugates were investigated. The application of SPI-GOS conjugates in noodles was also explored. The results observed that the glycation degree of SPI increased with the increasing reaction time. SDS-PAGE and spectral analysis showed the changes of spatial conformation of SPI after glycation. The antioxidant activity of SPI increased after glycation and DPPH radical scavenging activity of SPI-GOS peaked at 48 h of reaction. The hardness, elasticity and resilience of soybean protein gel reached their relative maximum at 48 h, 48 h and 12 h of glycation reaction, respectively. Moreover, the appropriate addition of glycated SPI improved the quality of noodles. The noodles with 4% addition of SPI-GOS had higher hardness, elasticity and tensile properties. This study will provide an effective method to modify soybean protein and expand the use of soybean protein in food industry. 展开更多
关键词 Soy protein isolate Glycation GALACTOOLIGOSACCHARIDE Functional properties NOODLES
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Mycobacterium gordoniasis of the cervical lymph nodes:A case report
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作者 Ling Peng Rong Ma +1 位作者 Yong Li Jie Cheng 《World Journal of Clinical Cases》 SCIE 2024年第19期3995-4002,共8页
BACKGROUND Owing to the advancement in bacterial identification techniques,the detection rate of non-tuberculous mycobacterium(NTM)has been on the rise.Different from Mycobacterium tuberculosis,the clinical symptoms o... BACKGROUND Owing to the advancement in bacterial identification techniques,the detection rate of non-tuberculous mycobacterium(NTM)has been on the rise.Different from Mycobacterium tuberculosis,the clinical symptoms of NTM are not easily detected,and the clinical efficacy and prognosis are somewhat heterogeneous.To report a case of Mycobacterium gordoniasis of cervical lymph node diagnosed in Anhui Chest Hospital in July 2022.CASE SUMMARY Upon examination,the patient who weighed 67.5 kg,was human immunodeficiency virus negative,healthy,without hypertension,diabetes,heart disease and other basic diseases microscopic analysis revealed granulomatous inflammation with coagulation necrosis in the lymphocyte,and tuberculosis was not ruled out.Plain computed tomography scans of the neck and chest indicated the presence of a single grayish-yellow and grayish-brown tissue,the dimensions of which was top of form 10.5 cm×3.0 cm×1.5 cm.After pathological consultation in our hospital,the diagnosis was confirmed as NTM infection.CONCLUSION This case report and the clinical epidemiological research on improving NTM have important guiding significance for improving decision-making in clinical treatments. 展开更多
关键词 mycobacterium gordoniasis Cervical lymph nodes Literature analysis Clinical treatments Case Report
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Overlapping infections of Mycobacterium canariasense and Nocardia farcinica in an immunocompetent patient:A case report
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作者 Hai-Yan Huang Kun-Peng Bu +1 位作者 Jin-Wei Liu Jing Wei 《World Journal of Clinical Cases》 SCIE 2024年第12期2079-2085,共7页
BACKGROUND Infections by non-tuberculous mycobacteria(NTM)have become more common in recent years.Mycobacterium canariasense(M.canariasense)was first reported as an opportunistic pathogen in 2004,but there have been v... BACKGROUND Infections by non-tuberculous mycobacteria(NTM)have become more common in recent years.Mycobacterium canariasense(M.canariasense)was first reported as an opportunistic pathogen in 2004,but there have been very few case reports since then.Nocardia is a genus of aerobic and Gram-positive bacilli,and these species are also opportunistic pathogens and in the Mycobacteriales order.Conventional methods for diagnosis of NTM are inefficient.Metagenomic next-generation sequencing(mNGS)can rapidly detect many pathogenic microorganisms,even rare species.Most NTM and Nocardia infections occur in immunocompromised patients with atypical clinical symptoms.There are no previous reports of infection by M.canariasense and Nocardia farcinica(N.farcinica),especially in immunocompetent patients.This case report describes an immunocompetent 52-year-old woman who had overlapping infections of M.canariasense,N.farcinica,and Candida parapsilosis(C.parapsilosis)based on mNGS.CASE SUMMARY A 52-year-old woman presented with a productive cough and chest pain for 2 wk,and recurrent episodes of moderate-grade fever for 1 wk.She received antibiotics for 1 wk at a local hospital,and experienced defervescence,but the productive cough and chest pain persisted.We collected samples of a lung lesion and alveolar lavage fluid for mNGS.The lung tissue was positive for M.canariasense,N.farcinica,and C.parapsilosis,and the alveolar lavage fluid was positive for M.canariasense.The diagnosis was pneumonia,and application of appropriate antibiotic therapy cured the patient.CONCLUSION Etiological diagnosis is critical for patients with infectious diseases.mNGS can identify rare and novel pathogens,and does not require a priori knowledge. 展开更多
关键词 Overlapping infection mycobacterium canariasense Nocardia farcinica Metagenomic next-generation sequencing technology Case report
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Seismic control of multi-degrees-of-freedom structures by vertical mass isolation method using MR dampers
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作者 Mohamad Shahrokh Abdi Masoud Nekooei Mohammad-Ali Jafari 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2024年第2期503-510,共8页
Vertical mass isolation(VMI)is one of the novel methods for the seismic control of structures.In this method,the entire structure is assumed to consist of two mass and stiffness subsystems,and an isolated layer is loc... Vertical mass isolation(VMI)is one of the novel methods for the seismic control of structures.In this method,the entire structure is assumed to consist of two mass and stiffness subsystems,and an isolated layer is located among them.In this study,the magnetorheological damper in three modes:passive-off,passive-on,and semi-active mode with variable voltage between zero and 9 volts was used as an isolated layer between two subsystems.Multi-degrees-of-freedom structures with 5,10,and 15 floors in two dimensions were examined under 11 pairs of near field earthquakes.On each level,the displacement of MR dampers was taken into account.The responses of maximum displacement,maximum inter-story drift,and maximum base shear in controlled and uncontrolled buildings were compared to assess the suggested approach for seismic control of the structures.According to the results,the semi-active control method can reduce the response by more than 12%compared to the uncontrolled mode in terms of maximum displacement of the mass subsystem of the structures.This method can reduce more than 16%and 20%of the responses compared to the uncontrolled mode in terms of maximum inter-story drift and base shear of the structure,respectively. 展开更多
关键词 seismic control vertical mass isolation base shear magnetorheological damper semi-active control
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