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A primer on stable parameter estimation and forecasting in epidemiology by a problem-oriented regularized least squares algorithm

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Infectious Disease Modelling 2017年第2期2卷 268-275页

作者： alexandra Smirnova Gerardo Chowell Department of Mathematics and Statistics Georgia State UniversityAtlantaUSA School of Public Health Georgia State UniversityAtlantaUSA Division of International Epidemiology and Population Studies Fogarty International CenterNational Institutes of HealthBethesdaMDUSA

Public health officials are increasingly recognizing the need to develop disease-forecasting systems to respond to epidemic and pandemic *** instance,simple epidemic models relying on a small number of parameters can play an important role in characterizing epidemic growth and generating short-term epidemic *** the absence of reliable information about transmission mechanisms of emerging infectious diseases,phenomenological models are useful to characterize epidemic growth patterns without the need to explicitly model transmission mechanisms and the natural history of the *** this article,our goal is to discuss and illustrate the role of regularization methods for estimating parameters and generating disease forecasts using the generalized Richards model in the context of the 2014e15 Ebola epidemic in West Africa.

关键词： Generalized Richards model Parameter estimation Regularization methods Epidemic forecasting Ebola

Long-term maintenance of stable copy number in the eukaryotic SMC family： origin of a vertebrate meiotic SMC1 and fate of recent segmental duplicates

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植物分类学报 2008年第3期46卷 405-423页

作者： alexandra SURCEL Xiaofan ZHOU Li QUAN Hong MA The lntercollege Graduate Program in Cell and Developmental Biology The Huck Institutes of the Life Sciences The Pennsylvania State University University Park PA 16802 USA Department of Biology The Pennsylvania State University University Park PA 16802 USA The Huck Institutes of the Life Sciences The Pennsylvania State University University Park PA 16802 USA Present address： Johns Hopkins University School of Medicine Baltimore MD 21205 USA

Members of the Structural Maintenance of Chromosome (SMC) family have long been of interest to molecular and evolutionary biologists for their role in chromosome structural dynamics, particularly sister chro-matid cohesion, condensation, and DNA repair. SMC and related proteins are found in all major groups of living organisms and share a common structure of conserved N and C globular domains separated from the conserved hinge domain by long coiled-coil regions. In eukaryotes there are six paralogous proteins that form three het-erodimeric pairs, whereas in prokaryotes there is only one SMC protein that homodimerizes. From recently com-pleted genome sequences, we have identified SMC genes from 34 eukaryotes that have not been described in previous reports. Our phylogenetic analysis of these and previously identified SMC genes supports an origin for the vertebrate meiotic SMC1 in the most recent common ancestor since the divergence from invertebrate animals. Additionally, we have identified duplicate copies due to segmental duplications for some of the SMC paralogs in plants and yeast, mainly SMC2 and SMC6, and detected evidence that duplicates of other paralogs were lost, suggesting differential evolution for these genes. Our analysis indicates that the SMC paralogs have been stably maintained at very low copy numbers, even after segmental (genome-wide) duplications. It is possible that such low copy numbers might be selected during eukaryotic evolution, although other possibilities are not ruled out.

关键词：真核脊椎动物减数分裂细胞

Addressing the MSICS learning curve: identification of instrument-holding techniques used by experienced surgeons

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International Journal of Ophthalmology(English edition) 2021年第5期14卷 693-699页

作者： alexandra J.Berges Zervin R.Baam Angela Zhu Shameema Sikder Samuel Yiu Ravilla D.Ravindran Kunal S.Parikh Johns Hopkins University School of Medicine BaltimoreMD 21287USA Aravind Eye Hospital MaduraiTamil Nadu 625001India Wilmer Eye Institute BaltimoreMD 21287USA Center for Nanomedicine BaltimoreMD 21231USA Department of Biomedical Engineering BaltimoreMD 21218USA Center for Bioengineering Innovation&Design BaltimoreMD 21218USA

AIM: To identify instrument holding archetypes used by experienced surgeons in order to develop a universal language and set of validated techniques that can be utilized in manual small incision cataract surgery(MSICS) curricula. METHODS: Experienced cataract surgeons performed five MSICS steps(scleral incision, scleral tunnel, side port, corneal tunnel, and capsulorhexis) in a wet lab to record surgeon hand positions. Images and videos were taken during each step to identify validated hand position ***: For each MSICS step, one or two major archetypes and key modifying variables were observed, including tripod for scleral incision, tripod-thumb bottom for scleral tunnel, underhand-index to thumb grip for side port, index-contact tripod for corneal entry, and tripodforceps for capsulorhexis. Key differences were noted in thumb placement and number of fingers supporting the instrument, and modifying variables included index finger curvature and amount of ***: Identification of optimal hand positions and development of a formal nomenclature has the potential to help trainees adopt hand positions in an informed manner, influence instrument design, and improve surgical outcomes.

关键词： cataract manual small incision cataract surgery instrument holding training learning curve

肺泡复张策略复合高水平呼气末正压通气不影响血容量充足的病态肥胖患者的血流动力学

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麻醉与镇痛 2011年第3期7卷 66-69页

作者： Stephan H. Bohm, md Oliver C. Thamm, md alexandra von Sandersleben, md Katrin Bangert, md Thomas E. Langwieler, md Gerardo Tusman, md Tim G. Strate, md, PhD Thomas G. Standl, md, PhD 邓希锦(译) Clinics of Anesthesiology Hospital Privado de Comunidad Mar del Plata Argentina General Visceral and Thoracic Surgery University Hospital Hamburg-Eppendorf Germany Hospital Privado de Comunidad Mar del Plata Argentina Department of Anesthesiology Hospital Privado de Comunidad Mar del Plata Argentina 不详

我们观察了20例血容量充足，准备行腹腔镜手术的病态肥胖（体重指数为50±9kg/m^2）患者，评估肺泡复张策略复合高水平呼气末正压通气（posidveend-expiratorypressure，PEEP）对其血流动力学的影响。肺泡复张策略是在有气腹和无气腹的... 详细信息

我们观察了20例血容量充足，准备行腹腔镜手术的病态肥胖（体重指数为50±9kg/m^2）患者，评估肺泡复张策略复合高水平呼气末正压通气（posidveend-expiratorypressure，PEEP）对其血流动力学的影响。肺泡复张策略是在有气腹和无气腹的情况下序贯进行，将PEEP水平逐渐升高，使平台压达到50—60cmH2O，呼吸10次／分，然后将PEEP水平逐渐降低。通过体循环和肺动脉导管的监测，没有发现肺泡复张及高水平PEEP对血流动力学产生显著的影响。经食管超声心动图显示左室舒张末期面积未发生变化，也无局部室壁运动异常的迹象。

关键词：呼气末正压通气血流动力学肥胖患者病态肥胖 P水平血容量肺泡复合

Serum vitamin D and colonic vitamin D receptor in inflammatory bowel disease

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World Journal of Gastroenterology 2016年第13期22卷 3581-3591页

作者： Yamilka Abreu-Delgado Raymond A Isidro Esther A Torres alexandra González Myrella L Cruz Angel A Isidro Carmen I González-Keelan Priscilla Medero Caroline B Appleyard Division of Gastroenterology Department of Medicine University of Puerto Rico Medical Sciences Campus-School of Medicine Department of Basic Sciences Physiology Division Ponce Health Sciences University-Medical School and Ponce Research Institute Department of Pathology and Laboratory Medicine University of Puerto Rico-Medical Sciences Campus

AIM: To determine serum vitamin D levels and colonic vitamin D receptor(VDR) expression in inflammatory bowel disease(IBD) and non-IBD patients and correlate these with ***: Puerto Rican IBD(n = 10) and non-IBD(n = 10) patients ≥ 21 years old scheduled for colonoscopy were recruited. Each patient completed a questionnaire and provided a serum sample and a colonic biopsy of normal-appearing mucosa. For IBD patients, an additional biopsy was collected from visually diseased mucosa. Serum vitamin D levels were measured by ultra-performance liquid chromatography and mass spectrometry. Hematoxylin and eosin stained tissue sections from colonic biopsies were classified histologically as normal or colitis(active/inactive), and scored for the degree of inflammation present(0-3, inactive/absent to severe). Tissue sections from colonic biopsies were also stained by immunohistochemistry for VDR, for which representative diagnostic areas were photographed and scored for staining intensity using a 4-point ***: The IBD cohort was significantly younger(40.40 ± 5.27, P < 0.05) than the non-IBD cohort(56.70 ± 1.64) with a higher prevalence of vitamin D deficiency(40% vs 20%, respectively) and insufficiency(70% vs 50%, respectively). Histologic inflammation was significantly higher in visually diseased mucosa from IBD patients(1.95 ± 0.25) than in normalappearing mucosa from control patients(0.25 ± 0.08, P < 0.01) and from IBD patients(0.65 ± 0.36, P < 0.05) and correlated inversely with VDR expression in visually diseased colonic tissue from IBD patients(r =-0.44, P < 0.05) and from IBD patients with Crohn's disease(r =-0.69, P < 0.05), but not in normal-appearing colonic tissue from control patients or IBD patients. Control and IBD patient serum vitamin D levels correlated positively with VDR expression in normal colon from control and IBD patients(r = 0.38, P < 0.05) and with patient age(r = 0.54, P < 0.01). CONCLUSION: Levels of serum vitamin D correl

关键词： Colitis Inflammation Vitamin D Vitamin D receptor Inflammatory bowel disease

Abnormal liver chemistries as a predictor of COVID-19 severity and clinical outcomes in hospitalized patients

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World Journal of Gastroenterology 2022年第5期28卷 570-587页

作者： Arunkumar Krishnan laura Prichett Xueting Tao Saleh A Alqahtani James P Hamilton Esteban Mezey alexandra T Strauss Ahyoung Kim James J Potter Po-Hung Chen Tinsay A Woreta Division of Gastroenterology and Hepatology Johns Hopkins University School of MedicineBaltimoreMD 21287United States Department of Pediatrics Johns Hopkins University School of MedicineBaltimoreMD 21287United States Liver Transplant Center King Faisal Specialist Hospital&Research CenterRiyadh 12713Saudi Arabia

BACKGROUND Abnormal liver chemistries are common findings in patients with Coronavirus Disease 2019(COVID-19).However,the association of these abnormalities with the severity of COVID-19 and clinical outcomes is poorly understood AIM We aimed to assess the prevalence of elevated liver chemistries in hospitalized patients with COVID-19 and compare the serum liver chemistries to predict the severity and in-hospital *** This retrospective,observational study included 3380 patients with COVID-19 who were hospitalized in the Johns Hopkins Health System(Baltimore,md,United States).Demographic data,clinical characteristics,laboratory findings,treatment measures,and outcome data were *** regression modeling was used to explore variables associated with abnormal liver chemistries on admission with disease severity and prognosis RESULTS A total of 2698(70.4%)had abnormal alanine aminotransferase(ALT)at the time of *** more prevalent abnormal liver chemistries were aspartate aminotransferase(AST)(44.4%),alkaline phosphatase(ALP)(16.1%),and total bilirubin(T-Bil)(5.9%).Factors associated with liver injury were older age,Asian ethnicity,other race,being overweight,and *** ALT,AST,T-Bil,and ALP levels were more commonly associated with disease *** adjusted Cox regression analysis revealed that abnormal AST and T-Bil were associated with the highest mortality risk than other liver injury indicators during *** AST,T-Bil,and ALP were associated with a need for vasopressor drugs,whereas higher levels of AST,T-Bil,and a decreased albumin levels were associated with mechanical ventilation CONCLUSION Abnormal liver chemistries are common at the time of hospital admission in COVID-19 patients and can be closely related to the patient’s severity and *** liver chemistries,specifically ALT,AST,ALP,and T-Bil levels,can be used to stratify risk and predict the need for advanced therapies in t

关键词： Severe acute respiratory syndrome coronavirus 2 Liver injury Liver tests Aspartate aminotransferase Alanine aminotransferase bilirubin

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右美托咪啶镇静对小儿心血管系统的影响

麻醉与镇痛 2013年第5期9卷 15-21页

作者： Jackson Wong, md Garry M. Steil, PhD Michelle Curtis, PNP alexandra Papas, BS David Zurakowski, PhD Keira P. Mason, md 郭志佳(译) 郭政(校) Department of Medicine Medicine Critical Care Program Children's Hospital Boston and Harvard Medical School Boston MA Children's Hospital Boston Boston MA Children Hospital Boston and Harvard Medical School Boston MA Department of Anesthesia Children Hospital Boston and Harvard Medical School Boston MA

背景右美托咪啶（dexmedetomidine，DEX）可影响成年人的心率（heartrate，HR）、平均动脉压、心脏指数（cardiacindex，CI）、心搏指数（strokeindex，SI）和体循环血管阻力指数（systemicvascularresistanceindex，SVRI）。本研究旨在探讨DEX镇静对小儿心血管系统是否存在类似作用。方法给予DEX后使用影像学方法监测小儿血流动力学的变化。第一组（DEX．短时）8例患者接受DEX2μg/kg于10分钟内输注完毕且手术在10分钟内完成；第二组（DEX．长时）9例患者在首次给药（DEX2μg／kg）的基础上按需追加DEX1μg／（kg·h），手术时间超过10分钟。使用无创心排血量探头监测CI、SI、SVRI。用重复测量的方差分析比较10分钟、20分钟和出室（Aldrete评分达9）3个时间点血流动力学与基础数值的差异，数据以均数表示（可信区间95％）。结果DEX-短时组共8例，DEX．长时组共9例。在DEX-短时组，T1点的HR和C1分别降低了18．9（2．3～35．5）次／分和0．74（0．15—1．33）L／（min·m2），其余无显著变化，所有指标在R，点都恢复到基础值。在DEX．长时组，HR、CI降低持续至恢复期[分别降低了24．0（8．3—39．6）次／分、1．51（0．95～2．06）L／（min·m2）]；同时，恢复期的SI降低8．0l（1．71-14．31）ml／m2，而SVRI升高[776．0（271．9—1280．4）dyn-s／（cm5·m2）]。两组的平均动脉压均未见显著变化。结论DEX使小儿Cl降低，且有累积效应。对于接受长时间手术的患者，胍、CI持续降低到患者出室，同时伴随SI降低、SVRI升高。

关键词：心血管系统右美托咪啶小儿镇静平均动脉压血流动力学血管阻力指数心脏指数

Cataract Surgery Third Edition

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Intralesional steroid is beneficial in benign refractory esophageal strictures:A meta-analysis

2010年

作者： Steinert, Roger F., md

CATARACT SURGERY Commissioning Editor: Russell Gabbedy Development Editor: alexandra Mortimer Editorial Assistant: Poppy Garroway Project Manager: Elouise Ball Design: Charles Gray Illustration Manager: Gillian Richar... 详细信息

ISBN: (纸本)9781416032250

关键词： Cataract Cataract Extraction

来源：畅想之星图书光盘版（南... 评论

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World Journal of Gastroenterology 2018年第21期24卷 2311-2319页

作者： László Szapáry Benedek Tinusz Nelli Farkas Katalin Márta Lajos Szakó Agnes Meczker Roland Hágendorn Judit Bajor Aron Vincze Zoltan Gyongyi alexandra Mikó Dezso Csupor Péter Hegyi Balint Eross Institute for Translational Medicine Medical SchoolUniversity of PécsPécs 7624Hungary Institute of Bioanalysis Medical SchoolUniversity of PécsPécs 7624Hungary Department of Gastroenterology First Department of MedicineMedical SchoolUniversity of PécsPécs 7624Hungary Department of Public Health Medicine Medical SchoolUniversity of PécsPécs 7624Hungary Department of Pharmacognosy Faculty of PharmacyUniversity of SzegedSzeged 6720Hungary

AIM To analyze the effect of intralesional steroid injections in addition to endoscopic dilation of benign refractory esophageal *** A comprehensive search was performed in three databases from inception to 10 April 2017 to identify trials, comparing the efficacy of endoscopic dilation to dilation combined with intralesional steroid injections. Following the data extraction, meta-analytical calculations were performed on measures of outcome by the randomeffects method of Der Simonian and Laird. Heterogeneity of the studies was tested by Cochrane's Q and I^2 statistics. Risk of quality and bias was assessed by the Newcastle Ottawa Scale and JADAD assessment *** Eleven articles were identified suitable for analyses, involving 343 patients, 235 cases and 229 controls in total. Four studies used crossover design with 121 subjects enrolled. The periodic dilation index(PDI) was comparable in 4 studies, where the pooled result showed a significant improvement of PDI in the steroid group(md:-1.12 dilation/month, 95% CI:-1.99 to -0.25 P = 0.012; I^2 = 74.4%). The total number of repeat dilations(TNRD) was comparable in 5 studies and showed a non-significant decrease(md:-1.17, 95%CI:-0.24-0.05, P = 0.057; I^2 = 0), while the dysphagia score(DS) was comparable in 5 studies and did not improve(Smd: 0.35, 95%CI:-0.38, 1.08, P = 0.351; I^2 = 83.98%) after intralesional steroid *** Intralesional steroid injection increases the time between endoscopic dilations of benign refractory esophageal strictures. However, its potential role needs further research.

关键词： Intralesional steroid Meta-analysis Benign refractory esophageal stricture Dilation