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Effect of sample size on the response of DEM samples with a realistic grading

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Particuology 2014年第4期12卷 107-115页

作者： Xin Huang kevin J.Hanley Catherine o'Sullivan Fiona C.Y.Kwok Skempton Building Department of Civil and Environmental EngineeringImperial College LondonLondon SW7 2AZUnited Kingdom Haking Wong Building Department of Civil EngineeringThe University of Hong Kong

This paper shows that for DEM simulations of triaxial tests using samples with a grading that is repre- sentative of a real soil, the sample size significantly influences the observed material response. Four DEM samples with identical initial states were produced： three cylindrical samples bounded by rigid wails and one bounded by a cubical periodic cell, When subjected to triaxial loading, the samples with rigid boundaries were more dilative, stiffer and reached a higher peak stress ratio than the sample enclosed by periodic boundaries. For the rigid-wall samples, dilatancy increased and stiffness decreased with increasing sample size, The periodic sample was effectively homogeneous, The void ratio increased and the contact density decreased close to the rigid walls, This heterogeneity reduced with increasing sample size. The positions of the critical state lines （CSLs） of the overall response in e-log p＇ space were sensitive to the sample size, although no difference was observed between their slopes. The critical states of the interior reg.ons of the rigid-wall-bounded samples approached that of the homogeneous periodic sample with increasing sample size. The ultimate strength of the material at the critical state is independent of sample size.

关键词： Discrete element method Sample size Rigid boundary Periodic boundary Critical state

Mixed ion and electron transport theory and application in solid oxide conductors

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International Journal of Minerals,Metallurgy and Materials 2022年第4期29卷 870-875页

作者： kevin Huang Department of Mechanical engineering University of South CarolinaColumbiaSC 292201USA

Mixed ions and electron conductors(MIECs)are an important family of electrocatalysts for electrochemical devices,such as reversible solid oxide cells,rechargeable metal-air batteries,and oxygen transport *** ionic and electronic transports in these materials play a key role in electrocatalytic *** in-depth fundamental understanding.of the transport phenomena is critically needed to develop better *** this brief review,we introduced generic ionic and electronic transport theory based on irreversible thermodynamics and applied it to practical oxide-based materials with oxygen vacancies and electrons/holes as the predominant *** oxide systems,namely Ceo_(2)-based and La Cro_(3)-based materials,are selected as case studies to illustrate the utility of the transport theory in predicting.oxygen partial pressure distribution across MIECs,electrochemical electronic/ionic leakage currents,and the effects of external load current on the leakage currents.

关键词： irreversible thermodynamics diffusivity charge neutrality electrochemical potential electrostatic potential

Surgical Treatment of osteonecrosis of the Femoral Head Using Minimally Invasive Surgical Drilling and Cancellous grafting at Brazzaville University Hospital

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open Journal of orthopedics 2024年第2期14卷 122-132页

作者： kevin Parfait Bienvenu Bouhelo-Pam Marius Monka Arnauld Sledje Wilfrid Bilongo Bouyou Regis Perry Massouama Paul Yèlai Ikounga Roger Bertrand Sah Mbou Armand Moyikoua Department of orthopaedic surgery and Traumatology University Hospital of Brazzaville Brazzaville Republic of the Congo Faculty of Health Sciences Marien N’GOUABI University Brazzaville Republic of the Congo

Introduction: osteonecrosis of the femoral head (oNTF) is a debilitating condition. Several treatments have been proposed with controversial results. The aim of our study was to evaluate treatment by surgical drilling coupled with in situ cancellous grafting. Materials and methods: our study was a case-control study conducted at Brazzaville University Hospital from 1st January 2018 to 31 December 2023. It compared two g.oups of patients with oNTF: non-operated (13 patients, 20 hips) and operated (22 patients, 35 hips). We used the visual digital scale (VDS) for pain assessment, the Merle D’Aubigne-Postel (MDP) scoring system for clinical and functional assessment, and the evolution of necrosis. Results: The g.oup of non-operated patients had a mean age of 35.69 ± 3.4 years, no improvement in pain with an EVN above seven at the last recoil and a mean g.obal MDP score falling from 12.7 before offloading to 10.13 at one year. The g.oup of patients operated on had a mean age of 37.86 ± 7.02 years, a significant reduction in pain (p = 0.00004) and a significantly increased MDP score (p = 0.0034). A comparison of the two g.oups of patients showed significant stabilization of the necrotic lesions in the operated patients (p = 0.00067), with better satisfaction in the same g.oup. Conclusion: Surgical drilling combined with grafting in the treatment of early-stage oNTF has improved progress in our series. The technique is reproducible and less invasive. It has made it possible to delay unfavorable progression and, consequently, hip replacement surgery.

关键词： Hip osteonecrosis of the Femoral Head Conservative Treatment Surgical Drilling Bone grafting

Treatment of Synovial Cysts in Relation to the Tibial Tunnel of Anterior Cruciate Ligament grafts by Filling the Tunnel with Acrylic Cement

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Surgical Science 2024年第4期15卷 289-298页

作者： Saint Luc Mungina Sedou Charlène Tshitala Mbombo Yannick Toko Kiama kevin Ndangi Ezechiel Nkodia Dieudonné Mwangala Rossyl Kivudi Dominique Saragaglia Luc Mokassa Bakumobatane Department of Surgery University Clinics of Kinshasa Faculty of Medicine University of Kinshasa Kinshasa Democratic Republic of Congo Matete general Reference Hospital Kinshasa Democratic Republic of Congo Department of orthopedic Surgery Osteoarthritis Surgery and Sports Tromatology at the Grenoble Hospital and University Center Grenoble France National Border Hygiene Program Kinshasa Democratic Republic of Congo

Introduction: Synovial cyst of the tibial tunnel in connection with anterior cruciate ligament (ACL) reconstruction is a rare but particularly troublesome complication. Medical treatment is often doomed to failure, and surgical treatment usually consists of excising the cyst and filling the tunnel with bone. The aim of this study was to evaluate the results of filling the tunnel with acrylic cement. Hypothesis: Filling the tibial bone tunnel with acrylic cement should eliminate communication between the joint cavity and the pre-tibial surface and prevent cyst recurrence. Patients and Methods: This retrospective series is composed of 13 patients, 9 men and 4 women, mean age 48.5 years (31 to 64) operated on between 2011 and 2019 for an intra- and extraosseous synovial cyst consecutive to the tibial tunnel of an ACL graft. Between 1983 and 2016, 12 of the patients had had a bone graft without bone block fixation (DI-DT or Mac Intosh) and one patient, a bone-bone transplant (KJ). The cyst was of variable size, located on the anteromedial aspect of the proximal end of the tibia, and often painful, warranting consultation. At the time of the initial operation, 9 patients had undergone meniscectomies (6 medial, 2 lateral, 1 double). In 7 knees, there were 7 cartilage lesions in the femorotibial and/or patellofemoral compartments (one stage 1 lesion, 2 stage 2 lesions, 4 stage 3 lesions, and no stage 4 lesions). only 2 knees had neither cartilage nor meniscus lesions. After curettage of the bone tunnel /− removal of the non-resorbed or PEEK interference screw, the tunnel was filled with acrylic cement /− reinforced with a ligament staple to prevent expulsion. All patients underwent regular follow-up consultations until recovery. Results: At a maximum follow-up of 8 years, only 1 cyst recurred, representing a 7.69% failure rate. It was reoperated with another technique, which involved filling the tibial bone tunnel with bone graft taken from a half-bank head. After recovery

关键词： Arthro-Synovial Cyst Tibial Tunnel ACL graft Filling Acrylic Cement

ASSESSMENT oF oPTICAL CLEARINg AgENTS USINg REFLECTANCE-MoDE CoNFoCAL SCANNINg LASER MICRoSCoPY

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Journal of Innovative optical Health Sciences 2010年第3期3卷 183-188页

作者： RAVIKANT SAMATHAM kevin g.PHILLIPS STEVEN L.JACQUES Departments of Dermatology and Biomedical Engineering.oregon Health and Science University 3303 SW Bond Avenue PortlandOR 97239USA

The mechanism of action of clearing agents to improve optical imaging.of mouse skin during reflectance-mode confocal microscopy was *** dermal side of excised dorsal mouse skin was exposed for one hour to saline,glycerin,or 80% DMSo,then the clearing agent was removed and the dermis placed against a glass cover slip through which a confocal microscope measured reflectance at 488 nm *** untreated control was also *** axial attenuation of reflectance signal,R(z_(f))versus increasing depth of focus zf behaved as R=ρexp(−μz_(f) 2g),where ρ is tissue reflectivity and μ is attenuation[cm^(−1)].The factor 2g accounts for the in/out path of photons,and the numerical aperture of the *** ρ,μ data were mapped to values of scattering coefficient(μ_(s)[cm^(−1)])and anisotropy of scattering(g).Images showed that glycerin significantly increased the g.of dermis from about 0.7 to about 0.99,with little change in the μ_(s) of dermis at about 300cm^(−1).DMSo and saline had only slight and inconsistent effects on g and μ_(s).

关键词： optical properties skin anisotropy

A Comprehensive overview of Skeletal Phenotypes Associated with Alterations in Wnt/β-catenin Signaling in Humans and Mice

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Bone Research 2013年第1期1卷 27-71页

作者： kevin A.Maupin Casey J.Droscha Bart o.Williams Program for Skeletal Pathobiology and Center for Tumor Metastasis Van Andel Research Institute333 Bostwick NEGrand RapidsMI 49503USA

The Wnt signaling pathway plays key roles in differentiation and development and alterations in this signaling pathway are causally associated with numerous human diseases. While several laboratories were examining roles for Wnt signaling in skeletal development during the 1990s, interest in the pathway rose exponentially when three key papers were published in 2001-2002. one report found that loss of the Wnt co-receptor, Low-density lipoprotein related protein-5 （LRPS）, was the underlying genetic cause of the syndrome osteoporosis pseudoglioma （oPPg）. oPPg is characterized by early-onset osteoporosis causing increased susceptibility to debilitating fractures. Shortly thereafter, two g.oups reported that individuals carrying a specific point mutation in LRP5 （g171V） develop high-bone mass. Subsequent to this, the causative mechanisms for these observations heightened the need to understand the mechanisms by which Wnt signaling controlled bone development and homeostasis and encouraged significant investment from biotechnology and pharmaceutical companies to develop methods to activate Wnt signaling to increase bone mass to treat osteoporosis and other bone disease. In this review, we will briefly summarize the cellular mechanisms underlying Wnt signaling and discuss the observations related to oPPg and the high-bone mass disorders that heightened the appreciation of the role of Wnt signaling in normal bone development and homeostasis. We will then present a comprehensive overview of the core components of the pathway with an emphasis on the phenotypes associated with mice carrying genetically engineered mutations in these genes and clinical observations that further link alterations in the pathway to changes in human bone.

关键词： Wnt signaling mouse models Lrp5/Lrp6 -catenin skeletal phenotypes

Multistage off-Line Permutation Packet Routing.on a Mesh:An Approach with Elementary Mathematics

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Journal of Computer Science & Technology 2009年第1期24卷 175-180页

作者： kevin Chiew School of Information Systems Singapore Management University80 Stamford RoadSingapore 178902

Various methods have been proposed for off-line permutation packet routing.on a mesh. one of the methods is known as multistage routing, in which the first stage is crucial. For the first stage of routing, the previous study normally converts it to a problem of graph theory and proves the existence of solutions. However, there is a lack of simple algorithms to the first stage of routing. This article presents an explicit and simple approach for the first stage of routing based on elementary mathematics.

关键词： permutation packet routing explicit algorithm

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地球科学的大数据、数字孪生与水文学

水利信息化 2024年第4期 99-100页

作者： Tiffany C.Vance Thomas Huang kevin A.Butler 包鑫如(编译) 不详

地球科学是研究地球物理、化学和生物系统及其相互作用的庞大而复杂的领域。随着基于地球和卫星的传感器数量和分辨率的提高,地球科学数据的体量呈爆炸式增长,这些数据有助于我们探索地球的复杂现象和变化过程,并推动数据分析、可视化... 详细信息

地球科学是研究地球物理、化学和生物系统及其相互作用的庞大而复杂的领域。随着基于地球和卫星的传感器数量和分辨率的提高,地球科学数据的体量呈爆炸式增长,这些数据有助于我们探索地球的复杂现象和变化过程,并推动数据分析、可视化等技术的发展。将地球科学中的大数据定义为对地球系统开展多种观测和模拟而得到的大量、多样且不断积累的复杂数据,这些数据的分析与应用不仅需要大量可用的计算资源,还需要先进的技术和工具。随着大数据和人工智能的应用与发展,用于发现、分析和可视化大数据的技术和工具不断涌现,如g.ogle Earth Engine,Apache Science Data Analytic Platform,The Pang.o Project等,这些平台具有广泛的地理空间数据和计算能力,显著提升了对地球系统的认知水平。

关键词：大数据人工智能地球科学传感器数量复杂数据地理空间数据 Apache 计算能力

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Philippine retinoblastoma initiative multi-eye center study 2010-2020

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International Journal of ophthalmology(English edition) 2024年第1期17卷 144-156页

作者： Roland Joseph D.Tan gary John V.Mercado Patricia E.Cabrera Paulita Pamela P.Astudillo Rolando Enrique D.Domingo Josept Mari S.Poblete Charmaine grace M.Cabebe Adriel Vincent R.Te Melissa Anne S.gonzales Jocelyn g.Sy Beltran Alexis A.Aclan Jayson T.So Fatima g.Regala Kimberley Amanda K.Comia Josemaria M.Castro Mara Augustine S.galang Aldous Dominic C.Cabanlas Benedicto Juan E.Aguilar gabrielle S.Evangelista Jo Michael Maniwan Andrei P.Martin Calvin Y.Martinez John Alfred H.Lim Rena Ivy Bascuna Rachel M.Ng kevin B.Agsaoay Kris Zanna A.Acluba-Arao Ellaine Rose V.Apostol Beatriz M.Prieto Department of ophthalmology and Visual Sciences Philippine General HospitalManila 1000Philippines Department of ophthalmology Baguio General Hospital and Medical CenterBaguio City 2600Philippines Department of ophthalmology Manila Doctors HospitalManila 1000Philippines Department of ophthalmology Rizal Medical CenterPasig City 1600Philippines Department of ophthalmology Jose B.Lingad Memorial Regional HospitalPampanga 2000Philippines Department of ophthalmology Southern Philippines Medical CenterDavao City 8000Philippines Department of ophthalmology East Avenue Medical CenterQuezon City 1100Philippines Department of ophthalmology Northern Mindanao Medical CenterCagayan de Oro City 9000Philippines Department of ophthalmology Cebu Velez General HospitalCebu City 6000Philippines Legazpi Eye Center Legazpi City 4500Philippines Department of ophthalmology Cagayan Valley Medical CenterTuguegarao City 3500Philippines

AIM:To provide a comprehensive and more representative national data on the disease,especially on treatment options and outcomes,and to determine access of retinoblastoma patients from Luzon,Visayas and Mindanao to eye care,and determine if access is associated with delay in consultation,staging and ***:Cohort study of retinoblastoma patients seen in eleven institutions located in the three major areas of the Philippines namely Luzon,Vizayas and Mindanao from ***:Totally 636 patients,involving 821 eyes,were ***(57%)were from Luzon and were seen in institutions in Luzon(72%).Annually,58±10 new cases were seen with 71%having unilateral *** delay of consultation remained long at 9(3,17)mo,longest in patients with unilateral disease(Pose from the Visayas(Pon the International Retinoblastoma Staging System,only 35%of patients had Stage 1 while 47%already had extraocular *** was the most common treatment received by 484 patients while intravenous chemotherapy was received by *** were 250(39%)patients alive,195(31%)dead,85(13%)abandoned,17(3%)refused and 89(14%)with no ***:This study presents the largest cohort of retinoblastoma patients in the Philippines in terms of patients’and participating institutions’number and g.ographical location and type of institution(private and public).It also presents more comprehensive data on the treatments used and outcomes(survival,g.obe salvage,and vision retention rates).Delay in consultation was still long among patients leading to advanced disease stage and lower survival *** increasing capacity to diag.ose and manage retinoblastoma in the country,the delay of consultation remains long primarily due to accessibility issues to eye care institutions especially in the Visayas and financial *** delay was still significant that overall survival rate remain low.

关键词： retinoblastoma Philippines clinical profile