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高效液相色谱法测定酶的活性

色谱 1992年第2期10卷 101-103页

作者：陈清轩 Leonard O.Rosik frederick sweet 中国科学院发育生物学研究所北京100080 华盛顿大学医学院美国圣路易斯

3β,20α-羟基甾体脱氢酶(3β,20α-HSD)是和胚胎的发育密切相关的;我们于1987年首次从胎羊血中得到该酶的纯品,并对其有关性质进行了研究。但是繁杂的测酶活方法常常延误研究工作的顺利进行,因此寻求一种简便有效的测定方法是很有意义... 详细信息

3β,20α-羟基甾体脱氢酶(3β,20α-HSD)是和胚胎的发育密切相关的;我们于1987年首次从胎羊血中得到该酶的纯品,并对其有关性质进行了研究。但是繁杂的测酶活方法常常延误研究工作的顺利进行,因此寻求一种简便有效的测定方法是很有意义的。经多次实验,我们成功地将高效液相色谱技术(HPLC)用于3β,20α-HSD的活性测定,大大缩短了测定时间,促进了有关研究工作的顺利进行。本文将介绍这种新的测酶活方法。

关键词：酶 20α-HSD 活性 HPLC 3β-HSD

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3β,20α-羟基甾体脱氢酶的动力学性质

生物化学杂志 1991年第2期7卷 177-182页

作者：陈清轩 Colin D.Nancarrow frederick sweet 中国科学院发育生物学研究所 CSIRO Division of Animal Production Prospect NSW 2148 Australia Depart.of OB/CYN Washington University School of Medicine St. LouisMO 63110 U.S.A.

3β,20α-羟基甾体脱氢酶(3β,20α-Hydroxysteroid dehydrogenase,3β,20α-HSD)是从胎羊血中分离得到的。分子量为35kD。该酶以NADPH为辅酶,有两种底物。以孕酮为底物时,Km=30.8μmol/L,Vmax=0.7nmol min^(-1)(nmol enzyme)^(-1);以5α-二氢睾酮(5α-Dihydrotestosterone,5α-DHT)为底物时,Km=74μmol/L,Vmax=1.3nmol min^(-1)(nmol enzyme)^(-1)。5α-DHT竞争性抑制20α-还原活性,Ki=102μmol/L。16α-溴代乙酰氧基(16α-Bromo acetoxyprogesterone,16α-BAP)是3β,20α-HSD不可逆竞争性抑制剂,t_(1/2)=75min。对3β和20α还原活性的抑制常数Ki分别为23μmol/L和58μmol/L。

关键词：羟甾体脱氢酶动力学

Reliability of a computerized system for strabismus screening

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International Journal of Ophthalmology(English edition) 2024年第1期17卷 126-130页

作者： Supaporn Tengtrisorn Alan frederick Geater Department of Ophthalmology Faculty of MedicinePrince of Songkla UniversityHat-YaiSongkla 90110Thailand Epidemiology Unit Faculty of MedicinePrince of Songkla UniversityHat-YaiSongkla 90110Thailand

AIM:To evaluate the reliability of Photo-Hirschberg screening for global strabismus performed by non-specialized ***:Participants at three sites were *** person at each site was trained in visual acuity measurement and use of the computerized *** acuity was measured,and strabismus testing was performed using two flash *** data from the three primary observers were sent to an experienced assistant researcher,who was blinded to the primary results,for *** primary and re-evaluation results of the Photo-Hirschberg screenings using weighted kappa for agreement were ***:The study included 181 participants(88 males and 93 females)and the results for primary and re-evaluation screenings were *** participants with contrasting results presented with unclear corneal light *** and specificity were 100%[95%confidence interval(CI):29.0%-100%]and 99.4%(95%CI:96.6%-100%),respectively,based on the Agresti test of the primary evaluation,considering the re-evaluated classification as ***:The computerized system can be used for primary strabismus screening by non-specialized personnel,with 98.8%agreement with ***,it cannot be used as a substitute for professional examination.

关键词： strabismus screening computerized system Photo-Hirschberg screening

Do tensile and shear forces exerted on cells influence mechanotransduction through stored energy considerations?

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BIOCELL 2024年第4期48卷 525-540页

作者： frederick H.SILVER TANMAY DESHMUKH Department of Pathology and Laboratory Medicine Robert Wood Johnson Medical SchoolRutgersThe State University of New JerseyPiscatawayNJ 08854USA OptoVibronex LLC.Ben Franklin Tech PartnersBethlehemPA 18015USA

All tissues in the body are subjected externally to gravity and internally by collagenﬁbril and cellular retractive forces that create stress and energy equilibrium required for *** involves mechanical work(force through a distance)and energy storage as kinetic and potential *** leads to changes in cell mitosis or apoptosis and the synthesis or loss of tissue *** involves the application of energy directly to cells through integrin-mediated processes,cell-cell connections,stretching of the cell cytoplasm,and activation of the cell nucleus via yes-associated protein(YAP)and transcriptional coactivator with PDZ-motif(TAZ).These processes involve numerous complexes,intermediate molecules,and multiple *** pathways have been identiﬁed from research studies on vertebrate cell culture and from studies in *** pathways involve mechanosensors and other molecules that activate the *** review discusses the mitogen-activated protein kinase(MAPK)family,Hippo,Hedgehog,and Wingless-related integration site(WNT)/βcatenin signaling *** mediators covered includeβcatenin,ion channels,growth factors,hormone receptors,members of the Ras superfamily,and components of the linker of nucleoskeleton and cytoskeleton(LINC)***,the interrelationship among the different pathways remains to be clariﬁ***-mediated mechanotransduction involves direct tensile loading and energy applied to the cell membrane via collagenﬁbril *** energy is transferred between cells by stretching the cell-cell connections involving cadherins and the WNT/βcatenin *** alterations induce changes in intracellular events in the cytoskeleton and nuclear skeleton caused by the release of YAP and *** coactivators then penetrate through the nuclear pores and inﬂuence nuclear cell *** in the balance of forces and energy applied to cells and tissues is hypothesized to shift th

关键词： MAPK family Hippo Hedgehog WNT pathway βcatenin Ion channels Growth factor receptors Hormone receptors Ras superfamily LINC complex Collagen Cadherins

Unicompartmental knee arthroplasty vs high tibial osteotomy for knee osteoarthritis:A comparison of clinical and radiological outcomes

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World Journal of Orthopedics 2024年第5期15卷 444-456页

作者： frederick William Wyatt Oday Al-Dadah Translational and Clinical Research Institute Faculty of Medical SciencesNewcastle UniversityNewcastle Upon Tyne NE24HHUnited Kingdom Department of Trauma and Orthopaedic Surgery South Tyneside District HospitalSouth Shields NE340PLUnited Kingdom

BACKGROUND Unicompartmental knee arthroplasty(UKA)and high tibial osteotomy(HTO)are well-established operative interventions in the treatment of knee ***,which intervention is more beneficial to patients with knee osteoarthritis remains unknown and a topic of much ***,there is a paucity of research assessing the relationship between radiographic parameters of knee joint alignment and patient-reported clinical outcomes,preoperatively and following HTO or *** To compare UKAs and HTOs as interventions for medial-compartment knee osteoarthritis:Examining differences in clinical outcome and investigating the relationship of joint alignment with respect to *** This longitudinal observational study assessed a total of 42 patients that had undergone UKA(n=23)and HTO(n=19)to treat medial compartment knee ***-reported outcome measures(PROMs)were collected to evaluate clinical *** included two disease-specific(Knee Injury and Osteoarthritis Outcome Score,Oxford Knee Score)and two generic(EQ-5D-5L,Short Form-12)*** radiographic parameters of knee alignment assessed were the:Hip-knee-ankle angle,mechanical axis deviation and angle of Mikulicz *** Statistical analyses demonstrated significant(P<0.001),preoperative to postoperative,improvements in the PROM scores of both *** were,however,no significant inter-group differences in the postoperative PROM scores of the UKA and HTO *** significant correlations associated a more distolaterally angled Mikulicz line with worse knee function and overall health preoperatively(P<0.05).Postoperatively,two clusters of significant correlations were observed between the disease-specific PROM scores and knee joint alignment parameters(hip-knee-ankle angle,mechanical axis deviation)within the HTO group;yet no such associations were observed within the UKA *** UKAs and HTOs are both efficacious operations that provide a comp

关键词： Arthroplasty Osteotomy Medial compartment Osteoarthritis Knee alignment Patient reported outcome measures

Surface and structure engineering of MXenes for rechargeable batteries beyond lithium

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Journal of Materiomics 2024年第1期10卷 253-268页

作者： Zefu Huang Majid Farahmandjou frederick Marlton Xin Guo Hong Gao Bing Sun Guoxiu Wang Centre for Clean Energy Technology School of Mathematical and Physical SciencesFaculty of ScienceUniversity of Technology SydneyUltimoNSW2007Australia Joint International Laboratory on Environmental and Energy Frontier Materials School of Environmental and Chemical Engineering Shanghai UniversityShanghai200444China

With the rapid growth in renewable energy,researchers worldwide are trying to expand energy storage *** development of beyond-lithium battery technologies has accelerated in recent years,amid concerns regarding the sustainability of battery ***,the absence of suitable high-performance materials has hampered the development of the next-generation battery ***,a family of 2D transition metal carbides and/or nitrides,have drawn significant attention recently for electrochemical energy storage,owing to their unique physical and chemical *** extraordinary electronic conductivity,compositional diversity,expandable crystal structure,superior hydrophilicity,and rich surface chemistries make MXenes promising materials for electrode and other components in rechargeable *** report especially focuses on the recent MXene applications as novel electrode materials and functional separator modifiers in rechargeable batteries beyond *** particular,we highlight the recent advances of surface and structure engineering strategies for improving the electrochemical performance of the MXene-based materials,including surface termination modifications,heteroatom doping strategies,surface coating,interlayer space changes,nanostructure engineering,and heterostructures and secondary materials ***,perspectives for building future sustainable rechargeable batteries with MXenes and MXene-based composite materials are presented based upon material design and a fundamental understanding of the reaction mechanisms.

关键词： MXenes Energy storage materials 2D materials Surface engineering Structure engineering

Design and Experimental Testing of a Moving Coil Actuator with Compensation Coil

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 707-716页

作者： Boyuan Yin Xianwu Zeng John frederick Eastham Emelie Nilsson Jean-francois Rouquette Jean Rivenc Ludovic Ybanez Xiaoze Pei Department of Electronics&Electrical Engineering University of BathBathBA27AYUnited Kingdom Airbus UpNext BlangnacFrance Airbus CRT BlangnacFrance Department of Mechanical Engineering University of BathBathBA27AYUnited Kingdom

Hydrogen-powered electric aircraft have attracted significant interests aiming to achieve decarbonization *** DC electric networks are facing great challenges in DC fault protection *** interrupters are widely used in low voltage and medium voltage power systems due to being environmentally friendly with low *** this paper a moving coil actuator with compensation coils for a vacuum interrupter,as part of a hybrid direct current circuit breaker,is designed and experimentally *** coils are used to improve operating speed compared with original moving coil *** between four possible connections of compensation coils and original moving coil actuator are carried *** results show comparisons between different connections of actuator coils in terms of opening time and coil current with a range of pre-charged capacitor *** performance of each actuator connection is also *** actuator with compensation coils is shown to have a higher current rising rate and achieve faster opening speed,which is a critical requirement for electric aircraft network *** parallel connection actuator achieves the highest opening speed within 3.5 ms with capacitor voltage of 50 V.

关键词： Circuit breaker compensation coil moving coil actuator vacuum interrupter

The effect of salt anion in ether‐based electrolyte for electrochemical performance of sodium‐ion batteries:A case study of hard carbon

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Carbon Energy 2024年第8期6卷 285-297页

作者： Jiabao Li Jingjing Hao Quan Yuan Ruoxing Wang frederick Marlton Tianyi Wang Chengyin Wang Xin Guo Guoxiu Wang College of Chemistry and Chemical Engineering Yangzhou UniversityYangzhouJiangsuChina School of Mathematical and Physical Sciences Centre for Clean Energy TechnologyFaculty of ScienceUniversity of Technology SydneySydneyAustralia

Compared with the extensively used ester‐based electrolyte,the hard carbon(HC)electrode is more compatible with the ether‐based counterpart in sodium‐ion batteries,which can lead to improved cycling stability and robust rate ***,the impact of salt anion on the electrochemical performance of HC electrodes has yet to be fully *** this study,the anionic chemistry in regulating the stability of electrolytes and the performance of sodium‐ion batteries have been systematically *** work shows discrepancies in the reductive stability of the anionic group,redox kinetics,and component/structure of solid electrolyte interface(SEI)with different salts(NaBF_(4),NaPF_(6),and NaSO_(3)CF_(3))in the typical ether solvent(diglyme).Particularly,the density functional theory calculation manifests the preferred decomposition of PF_(6)−due to the reduced reductive stability of anions in the solvation structure,thus leading to the formation of NaF‐rich *** investigation on redox kinetics reveals that the NaPF_(6)/diglyme can induce the fast ionic diffusion dynamic and low charge transfer barrier for HC electrode,thus resulting in superior sodium storage performance in terms of rate capability and cycling life,which outperforms those of NaBF_(4)/diglyme and NaSO_(3)CF_(3)/***,this work offers valuable insights for optimizing the electrochemical behaviors of electrode materials by regulating the anionic group in the electrolyte.

关键词： ether‐based electrolyte reaction kinetics salt anion SEI components sodium storage

The Importance of Posterior Tibial Slope in TKR: Pre and Post-Operative Measurements in United States Osteoarthritic Patients

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Open Journal of Orthopedics 2024年第8期14卷 374-379页

作者： frederick F. Buechel Sr frederick F. Buechel Jr Rutgers New Jersey Medical School Department of Orthopaedic Surgery Newark USA Lenox Hill Hospital Department of Orthopaedic Surgery New York USA

Background: Sagittal plane placement of the tibial component in total knee replacement (TKR) has important implications for maximizing the range of flexion motion, allowing collateral ligaments to function more normally, as well as providing ideal compressive loading on the tibial bone-prosthesis interface. This study attempts to quantify the normal posterior tibial slope (PTS) angle pre-operatively and post-operatively in osteoarthritic patients after using a conventional extramedullary tibial resection guide to assess its effectiveness. Methods: Forty-nine primary cementless total knee replacements in 34 osteoarthritic patients were measured radiographically pre-operatively and one year post-operatively to determine the PTS and its effect on range of motion. Lateral X-rays, using the anterior cortical line of the tibia, were employed for all measurements. Results: Pre-operative PTS measured 11.83˚ (range 5˚ - 18˚), while post-operative PTS of implanted tibial components measured 11.30o (range 4˚ - 18˚). The pre-operative range of motion of 112˚ (range 30˚ to 135˚) was improved to 119˚ (range 90˚ to 135˚) post-operatively after 1 year. Conclusions: Anterior tibial shaft referencing using a conventional extramedullary tibial resection guide provides an easy and convenient method for reproducing the anatomical PTS during TKR. This methodology provided improvement in average range of motion from 112˚ pre-operatively to 119˚ post-operatively at one year.

关键词： Posterior Tibial Slope Posterior Tibial Inclination Extramedullary Tibial Resection Guide Total Knee Alignment