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Friction 2024年第2期12卷 340-355页

作者： valentin L.POPOV Qiang LI Emanuel WILLERT Institute of Mechanics Technische Universität BerlinBerlin 10623Germany

In two recent papers,approximate solutions for compact non-axisymmetric contact problems of homogeneous and power-law graded elastic bodies have been suggested,which provide explicit analytical relations for the force–approach relation,the size and the shape of the contact area,as well as for the pressure distribution therein.These solutions were derived for profiles,which only slightly deviate from the axisymmetric shape.In the present paper,they undergo an extensive testing and validation by comparison of solutions with a great variety of profile shapes with numerical solutions obtained by the fast Fourier transform(FFT)-assisted boundary element method(BEM).Examples are given with quite significant deviations from axial symmetry and show surprisingly good agreement with numerical solutions.

关键词： normal contact non-axisymmetric indenter extremal principle generalized method of dimensionality reduction(MDR) functional elastic grading

Direct amplification of femtosecond optical vortices in a single-crystal fiber

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Photonics Research 2024年第1期12卷 27-32页

作者： CHANGSHENG ZHENG TIANYI DU LEI ZHU ZHANXIN WANG KANGZHEN TIAN YONGGUANG ZHAO ZHIYONG YANG HAOHAI YU valentin PETROV Jiangsu Key Laboratory of Advanced Laser Materials and Devices School of Physics and Electronic EngineeringJiangsu Normal UniversityXuzhou 221116China State Key Laboratory of Crystal Materials and Institute of Crystal Materials Shandong UniversityJinan 250100China Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy 12489 BerlinGermany

Spatially twisted light with femtosecond temporal structure is of particular interest in strong-field physics and light–matter interactions.However,present femtosecond vortex sources exhibit limited power handling capabilities,and their amplification remains an ongoing challenge particularly for high-order orbital angular momentum(OAM)states due to several inherent technical difficulties.Here,we exploit a straightforward approach to directly amplify a femtosecond optical vortex(FOV,OAM=-8?)by using a two-stage single-crystal fiber(SCF)amplifier system without pulse stretching and compression in the time domain,delivering 23-W,163-fs pulses at a repetition rate of1 MHz.The spatial and temporal features are well-conserved during the amplification,as well as the high modal purity(>96%).The results indicate that the multi-stage SCF amplifier system is particularly suited for direct amplification of high-order FOVs.The generated high-power femtosecond OAM laser beams are expected to help reveal complex physical phenomena in light–matter interactions and pave the way for practical applications in attoscience,laser plasma acceleration,and high-dimension micromachining.

关键词： fiber amplifier crystal

A cross-sectional analysis of the effectiveness of a nutritional support programme for people with tuberculosis in Southern Madagascar using secondary data from a non-governmental organisation

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Infectious Diseases of Poverty 2024年第1期13卷 101-102页

作者： Mara Anna Franke Julius valentin Emmrich Fierenantsoa Ranjaharinony Onja GbrilleRavololohanitra Harizaka Emmanuel Andriamasy Samuel Knauss Nadine Muller Global Digital Health Lab at Charité Center for Global Health Charité – Universitätsmedizin Berlin Berlin Germany London School of Hygiene and Tropical Medicine London UK Ärzte Für Madagaskar E.V. Leipzig Germany Heidelberg Institute of Global Health Heidelberg University Heidelberg Germany Berlin Institute of Health at Charité - Universitätsmedizin Berlin Berlin Germany Doctors for Madagascar Antananarivo Madagascar Speciality Network: Infectious Diseases and Respiratory Medicine Charité - Universitätsmedizin Berlin Berlin Germany

Background There is a strong,bi-directional link between tuberculosis(TB)and undernutrition:TB often causes undernutrition,and undernourished people are more likely to contract TB and experience worse outcomes.Globally,several TB nutritional support programmes exist;however,evidence on their effectiveness is limited and contested.This study evaluates the effect of a nutritional support programme implemented for people with TB in the Atsimo-Andrefana region,Madagascar in 2022.Within this programme,undernourished people with TB[with a body mass index(BMI)of<18.5 kg/m]receive 0.6 L of vegetable oil and 6.0 kg of a soy-wheat blend per month throughout their TB treatment.Methods We analysed secondary non-governmental organisation data collected between January and Novem-ber 2022 in the Atsimo-Andrefana region,Southern Madagascar,including information on an individual's medical conditions(e.g.,type of TB,treatment outcomes)and nutritional status measured prior to,during,and after comple-tion of treatment(e.g.,height,weight,mid-upper arm circumference).We conducted descriptive analyses of patient baseline characteristics and outcomes to assess the impact of the provided nutritional support on the BMI of people With TB.Results A total of 1310 people with TB were included in the study[9.9%(130)children under the age of 5,32.1%(420)children between 5 and 18 years,58.0%(760)adults].55.4% of children under 5,28.1% of children between ages 5 and 18,and 81.3%of adults were undernourished at treatment initiation.42.3%(55/130)of children under 5 experi-enced severe acute malnutrition at treatment uptake.While the average BMl of adults with TB receiving food support increased over time,from 17.1 kg/m^(2)(interquartile range:15.8-18.3,range:10.3-22.5)to 17.9 kg/m^(2)(interquartile range:16.6-19.1,range:11.9-24.1),most adults remained undernourished even after completing TB treatment.Conclusions The current TB nutritional support programme falls short of sufficiently increasing the BMl of people with TB to overcome malnutrition.The

关键词： Tuberculosis Sub-Saharan Africa Undernutrition Nutritional support

Zeolites for the environment

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Green Carbon 2024年第1期2卷 12-32页

作者： Qiaolin Lang Peng Lu Xiaobo Yang valentin Valtchev The ZeoMat Group Qingdao Institute of Bioenergy and Bioprocess TechnologyChinese Academy of SciencesLaoshan DistrictQingdao CN-266101China Normandie University ENSICAENUNICAENCNRSLaboratoire Catalyse et SpectrochimieCaen F-14000France

Zeolites are characterized by their microporous,crystalline structures with a four-connected framework with variable compositions,predominantly aluminosilicates.They are extensively utilized as adsorbents,catalysts,and ion exchangers across domestic and industrial sectors.With the ongoing energy transition from fossil fuels to renewable sources and the pursuit of environmentally sustainable development,zeolites are increasingly being explored beyond their traditional application fields.They are investigated for their adsorption and catalytic capabilities in the protection and restoration of air,water,and soil quality,as well as in the environmentally friendly“green”production of chemicals.This review article details these novel and potential applications of zeolites,emphasizing the unique properties that render them suitable for each specific use case and discussing how these properties can be fine-tuned through material selection or tailored synthesis methods.

关键词： Zeolite Environment Sorption Catalysis Air,water and soil protection Green production of chemicals

Allocation of patients with liver cirrhosis and organ failure to intensive care: Systematic review and a proposal for clinical practice

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World Journal of Gastroenterology 2015年第29期21卷 8964-8973页

作者： Katrine Prier Lindvig Ane Sogaard Teisner Jens Kjeldsen Thomas Strom Palle Toft valentin furhmann Aleksander Krag Department of Gastroenterology and Hepatology Odense University Hospital Department of Anestesiology and Intensive Care Odense University Hospital Department of Intensive Care Medicine University Medical Center Hamburg-Eppendorf

AIM: To propose an allocation system of patients with liver cirrhosis to intensive care unit(ICU), and developed a decision tool for clinical practice. METHODS: A systematic review of the literature was performed in Pub Med, MEDLINE and EMBASE databases. The search includes studies on hospitalized patients with cirrhosis and organ failure, or acute on chronic liver failure and/or intensive care therapy. RESULTS: The initial search identified 660 potentially relevant articles. Ultimately, five articles were selected; two cohort studies and three reviews were found eligible. The literature on this topic is scarce and no studies specifically address allocation of patients with liver cirrhosis to ICU. Throughout the literature, there is consensus that selection criteria for ICU admission should be developed and validated for this group of patients and multidisciplinary approach is mandatory. Based on current available data we developed an algorithm, to determine if a patient is candidate to intensive care if needed, based on three scoring systems: premorbid Child-Pugh Score, Model of End stage Liver Disease score and the liver specific Sequential Organ Failure Assessment score.CONCLUSION: There are no established systems for allocation of patients with liver cirrhosis to the ICU and no evidence-based recommendations can be made.

关键词： Cirrhosis Failure Intensive care Allocation Treatment

Cholera Recurrence within Benin Littoral County: Analysis of Epidemics from 2008, 2016 to 2023

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Open Journal of Epidemiology 2024年第2期14卷 353-365页

作者： Mongbo Virginie Avahoun valentin Agbomakouzo Evariste Sopoh Ghislain Aguemon Badirou Ouendo Edgard-Marius Regional Institute of Public Health Ministry of Public health of Benin Cotonou B&#233ninBenin Faculty of Health Sciences University of Abomey-Calavi Abomey-Calavi Benin

Introduction: Cholera is an acute diarrheal infection caused by the bacillus Vibrio cholerae, which can be fatal in a few hours if left untreated. It rages in endemic-epidemic mode in several countries, including Benin. Despite being the economic capital, the largest city in Benin and the most urbanized municipality in the country, the Littoral County, confounded with the city of Cotonou, is subject to recurrent epidemics. This paper aims to analyze successive cholera epidemics with a view of highlighting the factors contributing to this recurrence. Methods: A secondary analysis was done of the cholera-related databases of the County health office from 2016 to 2023, and its Situation Report No. 79 of December 7th, 2016, to describe the 2016 epidemic. Database data were analyzed in Excel. Results: Similarly to 2008, the 2016 cholera epidemic in Cotonou, which recorded 519 cases and 07 deaths, i.e. a case-fatality rate of 1.35%, spread to the town and six neighboring municipalities. The municipality of So-Ava, home to the index case, had the highest overall attack rate. The two epidemics share the same period of severity. Both epidemic and endemic cases are concentrated in the first seven boroughs of Cotonou, located on the lagoon shore, with low levels of hygiene and sanitation and a poor supply of drinking water. Conclusion: Low levels of hygiene, sanitation and drinking water supply all play a part in the recurrence of cholera epidemics. Sanitation work. Undertaken by the Beninese government is a ray of hope for improving this situation. Meanwhile, public awareness of hygiene measures must continue.

关键词： Recurrence Cholera Cotonou

Upper Tract Treatment of Urogenital Fistulas at the National Fistula Treatment Center (CNTF)

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Open Journal of Urology 2024年第1期14卷 11-19页

作者： Mahamat Ali Mahamat Vadandi valentin Aché Haroun Saleh Nedjim Abderassoul Abdraman Gadam Kimassoum Rimtebaye Faculty of Health Sciences University of N’Djamena N’Djamena Chad Faculty of Health Sciences University of Adam Barka Abeche Chad University Hospital of National Reference N’Djamena Chad

Introduction: Urogenital fistula is the existence of an abnormal pathway between a urinary organ and a genital organ. It is a public health problem because of its frequency and social aspect. The aim of this study was to analyse the management of urogenital fistulas by the upper route at the National Fistula Treatment Centre in N’Djamena. Material and Methods: This was a 10-year retrospective descriptive and analytical study from May 2011 to April 2021. The records of all patients who had received fistula treatment during this period were identified and analysed. Results: During the study period 2369 patients were managed for cure of urogenital fistula including 84 by the upper route, i.e. 3.5%. The mean age was 28.5 ± 8.13 years. Loss of urine was the most common reason for consultation (71.4%). Primigravida were represented in 50% (n = 42). The average gestational age was 3.2 ± 2.8 with extremes of 0 to 9 pregnancies. Obstetric aetiology was the most common (92.8%). Ureterovaginal fistulas were the most common anatomoclinical type (36.9%). Uretero-vesical reimplantation was the main surgical procedure (41.7%). Late postoperative follow-up was successful in 85.7% of cases. Conclusion: Urogenital fistulas are common in our practice. The only way to combat this scourge is through prevention through information, education and communication.

关键词： Urogenital Fistula Upper Tract CNTF N’Djamena Chad

Comparative Study of the Physicochemical Quality of the Waters of the Méné River (Sassandra Watershed, Ivory Coast) in the Dry Season and in the Rainy Season

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Journal of Environmental Protection 2024年第6期15卷 738-746页

作者： Konan Lopez Kouamé Gansso valentin Akilinon Olivier Simon Mananga Kombo Gneneyougo Emile Soro Bi Tié Albert Goula Science and Technology Department Alassane Ouattara University Bouak Ivory Coast Environmental Sciences Laboratory Nangui Abrogoua University Abidjan Ivory Coast

The study carried out on the waters of the Méné River led to an overall assessment of its water quality during the dry season and the rainy season. The analysis focused on eight (8) water samples taken from the river during a period of dry season (January-February) and a period of rainy season (June and September). The various physicochemical parameters were measured according to Afnor standardized methods. The readings of temperature, turbidity, pH and conductivity made it possible to account for the disturbances occurring in water quality. A temporal variation correlated with the seasons (dry or rainy) is noted. Turbidity depends on the concentration of suspended solids (SS) in the water and drained particles and therefore on the seasons. Just like the temperature, the conductivity changes with the season. The waters of the Méné River are generally acidic. The results obtained show that there is a low level of pollution by chlorides, phosphates, nitrites and nitrates. A slight pollution of the waters of Méné in organic matter (chemical oxygen demand values are less than 25 mg∙L−1 during dry season and 32.33 ± 4.73 mg∙L−1 during rainy season) was observed. The concentrations of metallic trace elements such as iron, manganese and aluminum indicate significant pollution of these waters by these elements. Overall, the waters of the Méné River are of satisfactory quality because all the physicochemical parameters analyzed have values below standards during the dry season as well as during the rainy season with the exception of COD and a few metallic trace elements.

关键词： Méné Physicochemical Parameters River Season Water Quality

Gangrene of the External Genitalia at Chu-Abeche

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Open Journal of Urology 2024年第4期14卷 197-206页

作者： Vadandi valentin Mahamat Ali Mahamat Abdelmahamoud Chene Vounouzia Barthelemy Temga Ouang Michael Minguemadji Allah Siyangar Ndormadjita Allah Siyangar Rimtebaye Kimassoum Urology Department University Hospital Center Abeche Chad Urology Department University Hospital of National Reference N&#8217Djamena Chad Urology Department University Hospital of Renaissance N&#8217Djamena Chad

Introduction: Gangrene of the external genitalia organs (EGO) is a medico-surgical emergency that is still very common in Third World countries. The main etiologies are urogenital, dermocutaneous and proctological. Mortality remains very high despite therapeutic advances. Our aim was to report on the epidemiological, diagnostic and therapeutic aspects of gangrene of the external genitalia, and to identify prognostic factors. Patients and Method: This was a 5-year retrospective descriptive study, from February 2016 to February 2021, of cases of gangrene of the external genitalia admitted to and treated in the Urology Department of Abeche University Hospital. Results: We collected 49 cases of gangrene of the external genitalia. The mean age of patients was 42 ± 16.81, with extremes of 20 and 81 years. The age group most concerned was between 20 and 29. The most frequent reasons for consultation were suppuration of the external genitalia and scrotal swelling. The average consultation time was 19.05 ± 16.02 days. The most common comorbidity was diabetes (35.9%). The most frequent pathological antecedents were urinary tract infections and endourethral maneuvers, reported in 40.5% and 38.7% respectively. Urogenital aetiology was predominant in 54.7%, and idiopathic in 35.9%. Lesions involved the scrotum in 60.6%, the scrotum and penis in 16.5%, and the penis alone in 5.7% of cases. Lesions extended to the perineum in 13.6% of cases, and to the abdomen in 3.6%. Vascular filling via the central venous line was performed in 58.6% of cases, and via the peripheral venous line in 41.4%. 3rd-generation cephalosporins and associated imidazoles were the most commonly used antibiotics. Necrosectomy was performed in 37 patients (73.4%), debridement combined with bypass cystostomy in 26.6% of cases. Colostomy was performed in 4% of cases. 90.8% of patients were cured and 9.2% died. The average hospital stay was 30 ± 75 days. Conclusion: The gangrene of the external genitalia is a medical and surgical emergency which has become rar

关键词： Gangrene External Genitalia Medical and Surgical Treatment

Epidemio-Clinical Aspects of Ecrectile Dysfunction in Type 2 Diabetics at Abeche Chu

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Open Journal of Urology 2024年第2期14卷 50-60页

作者： Vadandi valentin Mahamat Ali Mahamat Minguemadji Allah Siyangar Temga Ouang Michael Vounouzia Barthelemy Ndormadjita Allah Siyangar Abdelmahamoud Chene Konan Paul Gerard Rimtebaye Kimassoum Urology Department University Hospital Center Abeche Chad Urology Department University Hospital of National Reference N’Djamena Chad Urology Department University Hospital of Renaissance N’Djamena Chad Urology Department University Hospital Center Abidjan Cote d’Ivoire

Introduction: Erectile dysfunction (ED) is a frequent complication of diabetes and more frequently affects type 2 diabetics. It is often unrecognised or its management is delayed because it is often overshadowed by other complications. The aim of our study was to describe the epidemiological and clinical aspects of ED. Patients and Method: This was a descriptive cross-sectional study over an 8-month period from April to December 2021, of type 2 diabetic subjects with erectile dysfunction (ED) seen at the University Hospital of Abeche. Erectile function was assessed using the International Index of Erectile Function (IIEFS5). Results: Out of a total of 112 patients with type 2 diabetes, 64 agreed to take part in the study. Only 40 patients correctly completed the survey form. Of these, 34 (85%) had erectile dysfunction. On average, our patients were over 49.4 years old, and 55.9% of them had had diabetes for more than 10 years. Erectile dysfunction had affected the social life of 21 patients (61.76% of cases) and 28 (82.35%) had not been informed by a healthcare professional. Most of them, 31 cases or 91.17%, had never told their GP about their erectile dysfunction. The patients who thought that diabetes had an influence on their erectile dysfunction represented 74%. Diabetes was poorly controlled in 22 patients (64.70%). According to the International Index of Erectile Function (IIEF5), 85% of diabetic patients suffer from erectile dysfunction, including 28.6% with severe erectile dysfunction, 35.7% with moderate erectile dysfunction and 14.3% with mild erectile dysfunction. Erectile dysfunction was significantly more frequent in diabetics with arterial hypertension and poor diabetic control. Conclusion: The hospital prevalence of erectile dysfunction in our patients is high. Early detection of this disorder therefore remains a challenge to be met in order to organise better psychological and drug treatment.

关键词： Diabetes Erectile Dysfunction Screening