检索结果-南通市图书馆

A Study of the TPS Based Beam-Matching concept for Medical Linear Accelerators at a Tertiary Hospital

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Medical Physics, clinical Engineering and Radiation Oncology 2024年第1期13卷 16-25页

作者： ntombela n. Lethukuthula Rovetto J. nicolas nethwadzi c. Lutendo Mpumelelo nyathi Department of Radiation Oncology Steve Biko Academic Hospital Pretoria South Africa Department of Medical Physics University of Pretoria Pretoria South Africa Department of Medical Physics Sefako Makgatho Health Sciences University Ga-Rankuwa South Africa

The flexibility in radiotherapy can be improved if patients can be moved between any one of the department’s medical linear accelerators (LInAcs) without the need to change anything in the patient’s treatment plan. For this to be possible, the dosimetric characteristics of the various accelerators must be the same, or nearly the same. The purpose of this work is to describe further and compare measurements and parameters after the initial vendor-recommended beam matching of the five LInAcs. Deviations related to dose calculations and to beam matched accelerators may compromise treatment accuracy. The safest and most practical way to ensure that all accelerators are within clinical acceptable accuracy is to include TPS calculations in the LInAcs matching evaluation. Treatment planning system (TPS) was used to create three photons plans with different field sizes 3 × 3 cm, 10 × 10 cm and 25 × 25 cm at a depth of 4.5 cm in Perspex. calculated TPS plans were sent to Mosaiq to be delivered by five LInAcs. TPS plans were compared with five LInAcs measurements data using Gamma analyses of 2% and 2 mm. The results suggest that for four out of the five LInAcs, there was generally good agreement, less than a 2% deviation between the planned dose distribution and the measured dose distribution. However, one specific LInAc named “Asterix” exhibited a deviation of 2.121% from the planned dose. The results show that all of the LInAcs’ performance were within the acceptable deviation and delivering radiation dose consistently and accurately.

关键词： Radiotherapy Beam-Matching Linear Accelerator Dosimetry

Elevated brain temperature under severe heat exposure impairs cortical motor activity and executive function

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Sport and Health Science 2024年第2期13卷 233-244页

作者： Xiang Ren Tan Mary c.Stephenson Sharifah Badriyah Alhadad Kelvin W.Z.Loh Tuck Wah Soong Jason K.W.Lee Ivan c.c.Low Health and Social Sciences Singapore Institute of TechnologySingapore 138683Singapore Human Potential Translational Research Programme Yong Loo Lin School of MedicineNational University of SingaporeSingapore 117597Singapore centre for Translational Magnetic Resonance Research Yong Loo Lin School of MedicineNational University of SingaporeSingapore 117549Singapore Department of Physiology Yong Loo Lin School of MedicineNational University of SingaporeSingapore 117593Singapore Heat Resilience and Performance centre Yong Loo Lin School of MedicineNational University of SingaporeSingapore 117510Singapore n.1 Institute for Health National University of SingaporeSingapore 117456Singapore campus for Research Excellence and Technological Enterprise(cREATE) Singapore 138602Singapore

Background:Excessive heat exposure can lead to hyperthermia in humans,which impairs physical performance and disrupts cognitive *** heat is a known physiological stressor,it is unclear how severe heat stress affects brain physiology and ***:Eleven healthy participants were subjected to heat stress from prolonged exercise or warm water immersion until their rectal temperatures(T_(re))attained 39.5℃,inducing exertional or passive hyperthermia,*** a separate trial,blended ice was ingested before and during exercise as a cooling *** were compared to a control condition with seated rest(normothermic).Brain temperature(T_(br)),cerebral perfusion,and task-based brain activity were assessed using magnetic resonance imaging ***:T_(br)in motor cortex was found to be tightly regulated at rest(37.3℃±0.4℃(mean±SD))despite fluctuations in T_(re).With the development of hyperthermia,T_(br)increases and dovetails with the rising T_(re).Bilateral motor cortical activity was suppressed during high-intensity plantarflexion tasks,implying a reduced central motor drive in hyperthermic participants(T_(re)=38.5℃±0.1℃).Global gray matter perfusion and regional perfusion in sensorimotor cortex were reduced with passive *** function was poorer under a passive hyperthermic state,and this could relate to compromised visual processing as indicated by the reduced activation of left lateral-occipital ***,ingestion of blended ice before and during exercise alleviated the rise in both T_(re)and T_(bc)and mitigated heat-related neural ***:Severe heat exposure elevates T_(br),disrupts motor cortical activity and executive function,and this can lead to impairment of physical and cognitive performance.

关键词： Brain functional activity cognition Heat stress Hyperthermia Motor function

Single atom cu-n-c catalysts for the electro-reduction of cO_(2) to cO assessed by rotating ring-disc electrode

在线全文

学校读者我要写书评

暂无评论

Journal of Energy chemistry 2024年第1期88卷 169-182,I0004页

作者： S.Pérez-Rodríguez M.Gutiérrez-Roa c.Giménez-Rubio D.Ríos-Ruiz P.Arévalo-cid M.V.Martínez-Huerta A.Zitolo M.J.Lázaro D.Sebastián Instituto de carboquímica(cSIc) Miguel Luesma Castán 450018 ZaragozaSpain Instituto de catálisis y Petroleoquímica(cSIc) Marie Curie 228049 MadridSpain Synchrotron SOLEIL L’Orme des MerisiersDépartementale 12891190France

The electrochemical cO_(2) reduction reaction(cO_(2)RR) to controllable chemicals is considered as a promising pathway to store intermittent renewable energy. Herein, a set of catalysts based on copper-nitrogendoped carbon xerogel(cu-n-c) are successfully developed varying the copper amount and the nature of the copper precursor, for the efficient cO_(2)RR. The electrocatalytic performance of cu-n-c materials is assessed by a rotating ring-disc electrode(RRDE), technique still rarely explored for cO_(2)RR. For comparison, products are also characterized by online gas chromatography in a H-cell. The as-synthesized cu-nc catalysts are found to be active and highly cO selective at low overpotentials(from -0.6 to -0.8 V ***) in 0.1 M KHcO_(3), while H_(2) from the competitive water reduction appears at larger overpotentials(-0.9 V vs. RHE). The optimum copper acetate-derived catalyst containing cu-n_(4) moieties exhibits a cO_(2)-to-cO turnover frequency of 997 h^(-1) at -0.9 V vs. RHE with a H_(2)/cO ratio of 1.8. These results demonstrate that RRDE configuration can be used as a feasible approach for identifying electrolysis products from cO_(2)RR.

关键词： cu-n-c carbon xerogel Rotating ring disc electrode carbon dioxide reduction reaction carbon monoxide

Forecasting tropical cyclone coastal and marine hazards and impacts

在线全文

学校读者我要写书评

暂无评论

Tropical cyclone Research and Review 2024年第1期13卷 1-14页

作者： nadao Kohno cody Fritz Monica Sharma Robbie Berg Diana Greenslade Devon Telford Sakeasi Rabitu P.L.n.Murty M.Mohapatra Maria cristina c.Uson Japan Meteorological Agency TokyoJapan national Hurricane center MiamiUSA India Meteorological Department New DelhiIndia Bureau of Meteorology MelbourneAustralia Environment and climate change canada QuebecCanada Fiji Meteorological Service NadiFiji Philipine Atmospheric Geophysical and Astronomical Services AdministrationQuezon CityPhilippines

The report highlights the signiﬁcant progress over various regions with respect to understanding of coastal hazards,numerical modeling techniques and the generation&dissemination of coastal hazard warnings and *** developments over various regions in the globe during 2014–18 have been discussed in this report as presented during 10th Session of International Workshop on Tropical cyclones(IWTc-X)at Bali,*** speciﬁcally,various regions have started to confront the uncertainty that cannot be removed from Tc analyses and forecasts and further communicate those hazards within the context of risk[probabilistic]based *** also includes impact-based forecasts such as communicating coastal inundation information relative to total water level instead of storm surge,speciﬁcally(i.e.,anomaly from as-tronomical tide and waves).Lastly,updates to model grid conﬁguration,model resolution,and coupled dynamical systems continue to resolve the costal hazards more *** approaches have likely helped reduce loss of life relative to historical ***,regions agree that the generation and dissemination of coastal hazard information still need to be improved in view of growing population along the coast and thus increased exposure of life to coastal hazard.

关键词： coastal inundation Storm surge Probabilistic forecast

Silk-based nerve guidance conduits with macroscopic holes modulate the vascularization of regenerating rat sciatic nerve

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

neural Regeneration Research 2025年第6期20卷 1789-1800页

作者： carina Hromada Patrick Heimel Markus Kerbl LászlóGál Sylvia nürnberger Barbara Schaedl James Ferguson nicole Swiadek Xavier Monforte Johannes c.Heinzel Antal nógrádi Andreas H.Teuschl-Woller David Hercher Department Life Science Engineering University of Applied Sciences Technikum WienViennaAustria Austrian cluster for Tissue Regeneration ViennaAustria Ludwig Boltzmann Institute for Traumatology The Research Center in Cooperation with AUVAViennaAustria University clinic of Dentistry Medical University of ViennaViennaAustria Department of Plastic Reconstructive and Aesthetic SurgeryLandesklinikum Wiener Neustadt2700 Wiener NeustadtAustria Department of Anatomy Histology and EmbryologyAlbert Szent-Györgyi Medical SchoolUniversity of SzegedSzegedHungary Medical University of Vienna Department of Orthopedics and Trauma SurgeryDevision of Trauma SurgeryViennaAustria Department of Hand- PlasticReconstructive and Burn SurgeryBG Unfallklinik TuebingenUniversity of TuebingenTuebingenGermany

Peripheral nerve injuries induce a severe motor and sensory deficit. Since the availability of autologous nerve transplants for nerve repair is very limited, alternative treatment strategies are sought, including the use of tubular nerve guidance conduits(tnGcs). However, the use of tnGcs results in poor functional recovery and central necrosis of the regenerating tissue, which limits their application to short nerve lesion defects(typically shorter than 3 cm). Given the importance of vascularization in nerve regeneration, we hypothesized that enabling the growth of blood vessels from the surrounding tissue into the regenerating nerve within the tnGc would help eliminate necrotic processes and lead to improved regeneration. In this study, we reported the application of macroscopic holes into the tubular walls of silk-based tnGcs and compared the various features of these improved silk^(+) tnGcs with the tubes without holes(silk^(–) tnGcs) and autologous nerve transplants in an 8-mm sciatic nerve defect in rats. Using a combination of micro-computed tomography and histological analyses, we were able to prove that the use of silk^(+) tnGcs induced the growth of blood vessels from the adjacent tissue to the intraluminal neovascular formation. A significantly higher number of blood vessels in the silk^(+) group was found compared with autologous nerve transplants and silk^(–), accompanied by improved axon regeneration at the distal coaptation point compared with the silk^(–) tnGcs at 7 weeks postoperatively. In the 15-mm(critical size) sciatic nerve defect model, we again observed a distinct ingrowth of blood vessels through the tubular walls of silk^(+) tnGcs, but without improved functional recovery at 12 weeks postoperatively. Our data proves that macroporous tnGcs increase the vascular supply of regenerating nerves and facilitate improved axonal regeneration in a short-defect model but not in a critical-size defect model. This study suggests that further optimizatio

关键词： axon regeneration blood vessel functional recovery macroporous nerve lesion peripheral nerve repair sciatic nerve silk-based nerve guidance conduit vascularization

The effectiveness of different wear indicators in quantifying wear on railway wheels of freight wagons

在线全文

学校读者我要写书评

暂无评论

Railway Engineering Science 2024年第3期32卷 307-323页

作者： Philipe Augusto de Paula Pacheco M.Magelli Matheus Valente Lopes Pedro Henrique Alves correa n.Zampieri n.Bosso Auteliano Antunes dos Santos Federal Institute of the Southeast of Minas Gerais(IF Sudeste MG) Técnico PanamáStreet 45Santos DumontMG 36246-311Brazil Railway Laboratory(Lafer) Universidade Estadual de Campinas(UNICAMP)Mendeleyev Street 200CampinasSP 13083-872Brazil Department of Mechanical and Aerospace Engineering Politecnico Di TorinoC.so Duca degli Abruzzi 2410129 TurinItaly

Railway infrastructure relies on the dynamic interaction between wheels and rails;thus,assessing wheel wear is a critical aspect of maintenance and *** paper focuses on the wheel-rail wear indicator T-gamma(Tγ).Amidst its use,it becomes apparent that Tγ,while valuable,fails to provide a comprehensive reflection of the actual material removal and actual contact format,which means that using only Tγas a target for optimization of profiles is not *** this work,three different freight wagons are evaluated:a meter-gauge and a broad-gauge heavy haul vehicles from South American railways,and a standard-gauge freight vehicle operated in Europe,with different axle loads and dissimilar new wheel/rail *** vehicles are subjected to comprehensive multibody simulations on various *** simulations aimed to elucidate the intricate relationship between different wear indicators:Tγ,wear index,material removal,and maximum wear depth,under diverse curves,non-compensated lateral accelerations(A_(nc)),and *** findings showed a correlation of 0.96 between Tγand wear depth and 0.82 between wear index and material removed for the outer *** the results,the Tγis better than the wear index to be used when analyzing wear depth while the wear index is more suited to foresee the material *** results also show the low influence of A_(nc)on wear index and Tγ.By considering these factors together,the study aims to improve the understanding of wheel-rail wear by selecting the best wear analysis approaches based on the effectiveness of each parameter.

关键词： Wear index Wear volume Wear modeling Dynamic simulation

Hierarchical control Strategy for Load Regulation Based on Stackelberg Game Theory considering Randomness

在线全文

学校读者我要写书评

暂无评论

cSEE Journal of Power and Energy Systems 2024年第3期10卷 929-941页

作者： Tingyu Jiang Ping Ju c.Y.chung Yuzhong Gong college of Energy and Electrical Engineering Hohai UniversityNanjing 211100China Department of Electrical Engineering City University of Hong KongHong Kong CF624China Department of Electrical and computer Engineering University of SaskatchewanSaskatoonSK S7N 5A9Canada cSEE IEEE

Demand response has been recognized as a valuable functionality of power systems for mitigating power *** paper proposes a hierarchical control strategy among the distribution system operator(DSO),load aggregators(LAs),and thermostatically controlled loads(TcLs);the strategy includes a scheduling layer and an executive layer to provide load *** the scheduling layer,the DSO(leader)offers compensation price(cP)strategies,and the LAs(followers)respond to cP strategies with available regulation power(ARP)*** of the DSO and LAs are modeled according to their behaviors during the load regulation *** game is adopted to capture interactions among the players and leader and to obtain the optimal strategy for each participant to achieve ***,considering inevitable random factors in practice,e.g.,renewable generation and behavior of users,two different stochastic models based on sample average approximation(SAA)and parameter modification are formulated with improved scheduling *** the executive layer,distributed TcLs are triggered based on strategies determined in the scheduling layer.A self-triggering method that does not violate user privacy is presented,where TcLs receive external signals from the LA and independently determine whether to alter their operation *** simulations are performed on the modified IEEE-24 bus system to verify effectiveness of the proposed strategy.

关键词： Demand response hierarchical control load regulation self-triggering method Stackelberg game

clinical and demographic features of patients undergoing videocapsule endoscopy management:A descriptive study

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastrointestinal Endoscopy 2024年第7期16卷 424-431页

作者： María c Mejía Luis G Piñeros Luis M Pombo Laura A León Jenny A Velásquez Aníbal A Teherán Karen P Ayala Research center Fundación Universitaria Juan N.CorpasBogotá111321Colombia Fundación Universitaria Juan n.corpas Bogotá111321Colombia Department of Gastroenterology Universidad Militar Nueva GranadaBogotá111711Colombia Department of Gastroenterology Hospital Universitario Clínica San RafaelBogotá111711Colombia

BAcKGROUnD Video-capsule endoscopy(VcE)is an efficient tool that has proven to be highly useful in approaching several gastrointestinal *** was implemented in colombia in 2003,however current characterization of patients undergoing VcE in colombia is limited,and mainly comes from two investigations conducted before the SARS-coV-2 pandemic *** To describe the characteristics of patients undergoing VcEs and establish the main indications,findings,technical limitations,and other outstanding *** A descriptive study was carried out using data from reports of VcE(Pillcam SB3 system)use in a Gastroenterology Unit in Bogotá,colombia between September 2019 and January *** and clinical variables such as indication for the VcE,gastric and small bowel transit times(GTT,SBTT),endoscopic preparation quality,and limitations were described[n(%),median(IQR)].RESULTS A total of 133 VcE reports were *** were in men with a median age of 70 *** majority had good preparation(96.2%),and there were technical limitations in 15.8%of *** main indications were unexplained anemia(91%)or occult bleeding(23.3%).The median GTT and SBTT were 14 and 30 minutes,*** frequencies of bleeding stigma(3.79%)and active bleeding(9.09%)were low,and the most frequent abnormal findings were red spots(28.3%),erosions(17.6%),and vascular ectasias(12.5%).cOncLUSIOn VcE showed high-level *** main indication was unexplained *** bleeding was the most frequent *** with artificial intelligence,VcE can improve diagnostic precision and targeted therapeutic interventions.

关键词： Endoscopy Video-capsule endoscopy capsule endoscopy Gastrointestinal diseases Observational study Gastrointestinal bleeding

Phanerozoic co-evolution of O2-cO2 and ocean habitability

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

national Science Review 2024年第6期11卷 18-21页

作者： Zunli Lu Rosalind E.M.Rickaby Jonathan L.Payne Ashley n.Prow Department of Earth & Environmental Sciences Syracuse University Department of Earth Sciences University of Oxford Department of Earth and Planetary Sciences Stanford University

Atmospheric carbon dioxide and oxygen concentrations are partially linked via the geological cycle of organic carbon （Fig. 1A–c; e.g. cO2+H2O■cH2O+O2）. The history of these two biologically active components, controls on their concentrations, and implications for the complexity of the biosphere and habitability of Earth have been hotly debated, but are generally considered independently.

关键词： cO2-cOncEnTRATInG MEcHAnISM OXYGEn EVOLUTIOn AnOXIA