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Microalloyed Steels for Heat Treating Applications at Higher Process Temperatures

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Journal of Iron and Steel Research International 2011年第S1期18卷 80-89页

作者： David K.Matlock john G.Speer steven G.Jansto Marcus Stuart Advanced Steel Processing and Products Research Center Colorado School of MinesGoldenColorado USA CBMM-Reference Metals BridgevillePA CBMM Sao PauloBrasil

The potential is considered for use of microalloyed bar steels,in conjunction with thermomechanical processing,to enhance the properties of steels heat treated at higher process temperatures than have been used *** examples are highlighted:microalloyed spring steels with enhanced resistance to tempering and Nb-modified gear steels for high temperature vacuum carburizing,*** the order of 1050℃ versus 930℃ for a typical gas carburizing *** the spring steel example,the Nb+V steel results in significantly finer prior austenite grain sizes than the other steels considered,enhanced fatigue performance,and improved *** the Nb-modified carburizing steel,Nb additions up to 0.1 wt pct to a Ti-modified 8620 steel,in conjunction with thermomechanical processing to control initial precipitate distributions prior to carburizing,are shown to lead to materials with improved resistance to abnormal austenitic grain growth at the higher process *** content and heating rate to the carburizing temperature were shown to be important variables and suppression of abnormal grain growth was correlated with the development of a critical distribution of fine NbC precipitates,stable at the austenitizing temperature leading to improved fatigue performance in steels with fine and uniform grain *** for extending the results of this study to alloy design and controlled rolling in bar mills are assessed.

关键词： microalloying niobium thermomechanical processing carburizing abnormal grain growth

Artificial intelligence applications in inflammatory bowel disease:Emerging technologies and future directions

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World Journal of Gastroenterology 2021年第17期27卷 1920-1935页

作者： john Gubatan steven Levitte Akshar Patel Tatiana Balabanis Mike T Wei Sidhartha R Sinha Division of Gastroenterology and Hepatology Stanford University School of MedicineRedwood CityCA 94063United States

Inflammatory bowel disease(IBD)is a complex and multifaceted disorder of the gastrointestinal tract that is increasing in incidence worldwide and associated with significant *** rapid accumulation of large datasets from electronic health records,high-definition multi-omics(including genomics,proteomics,transcriptomics,and metagenomics),and imaging modalities(endoscopy and endomicroscopy)have provided powerful tools to unravel novel mechanistic insights and help address unmet clinical needs in *** the application of artificial intelligence(AI)methods has facilitated the analysis,integration,and interpretation of large datasets in IBD,significant heterogeneity in AI methods,datasets,and clinical outcomes and the need for unbiased prospective validations studies are current barriers to incorporation of AI into clinical *** purpose of this review is to summarize the most recent advances in the application of AI and machine learning technologies in the diagnosis and risk prediction,assessment of disease severity,and prediction of clinical outcomes in patients with IBD.

关键词： Artificial intelligence Machine learning Inflammatory bowel disease Crohn’s disease Ulcerative colitis Clinical outcomes

Understanding and managing sanitary risks due to rodent zoonoses in an African city: beyond the Boston Model

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Integrative Zoology 2008年第1期3卷 38-50页

作者： Peter J.TAYLOR Lorraine ARNTZEN Mel HAYTER Malcolm ILES john FREAN steven BELMAIN Durban Natural Science Museum eThekwini Libraries and Heritage DepartmentDurbanSouth Africa National Institute for Communicable Diseases National Health Laboratory ServiceSandringhamSouth Africa City Health:Communicable Diseases eThekwini MunicipalityDurbanSouth Africa Natural Resources Institute Chatham MaritimeKentUK

The Boston Model describes a successful rodent management plan that succeeded in a first-world city in the *** third-world cities, which often contain informal shack settlements, it is debatable whether the Boston Modelwould apply. In Durban, a major harbor city of three million people on the east coast of South Africa, we investigatedthe sanitary risks due to rodents in both formal (residential and commercial) and informal (shacks) sectors,and we evaluated the relative merits of different management interventions suggested by the Boston Model. Bloodand tissue samples of six species (Rattus norvegicus, R. tanezumi, R. rattus, Mus musculus, Mastomys natalensis,Tatera brantsi) from 262 live-trapped rodents from 54 localities were tested for antibodies or DNA for plague (n =193: antibody test), leptospirosis (n = 221 for antibody test;n = 69 for polymerase chain reaction test for DNA) andtoxoplasmosis (n = 217: antibody test). We conducted a socioeconomic survey of 90 household to determine environmentaland socioeconomic disease risk factors in the shack settlement of Cato Crest . No rodents wereseropositive for plague, but nine Norway rats, R. norvegicus (4.1% of the sample tested) were seropositive fortoxoplasmosis, and 22 R. norvegicus (10.0% of sample tested) were seropositive for leptospirosis. Disease endemicareas were concentrated in Cato Crest and the commercial district of Durban. Serology tests of humans living inCato Crest (n = 219) showed 0% exposure to plague, 23% to leptospirosis and 35% to toxoplasmosis. Comparedwith shack-dwellers, the residents of brick houses had slightly lower levels of exposure to leptospirosis andtoxoplasmosis. Based on our results, environmental hygiene and rodent-trapping campaigns were launched in CatoCrest. The initiative owes much of its current success to implementation of the principles inherent in the BostonModel, even though certain elements were lacking.

关键词： Durban leptospirosis plague rodent zoonoses toxoplasmosis.

Redo sphincteroplasty:are the results sustainable?

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Gastroenterology Report 2016年第1期4卷 39-42,I0002页

作者： Kwangdae Hong Giovanna Dasilva john T.Dollerschell David Maron steven D.Wexner Department of Colorectal Surgery Cleveland Clinic FloridaWestonFLUSA

Objective:This study aimed to investigate the long-termoutcomes of patients who undergo redo sphincteroplasty(RS).Methods:Patients with fecal incontinence(FI)who underwent RS between November 1988 and December 2011 were retrospectively identified from a prospective database.A questionnaire and telephone survey assessed current Cleveland Clinic Fecal Incontinence Score(CCFFIS;best 0,worst 20)and Fecal Incontinence Quality of Life(FIQoL;best 4.1,worst 1)*** was defined as no further continence surgery,no stoma and CCFFIS<9 at completion of *** Wilcoxon and Mann-Whitney U tests were used for comparing quantitative *** logistic regression analysis was done to identify predictive factors for ***:Fifty-six(66.7%)of 84 patients who underwent RS were available for evaluation at a median follow-up of 74(range:12-283)*** mean CCFFIS decreased from 16.563.7 to 11.966.6(P<0.001)at last *** patients(21.4%)underwent further continence surgery for failed sphincteroplasty,three(5.4%)of whom had a permanent *** patients(32.1%)had a CCFFIS<9 at the completion of follow-up,and 16(28.6%)had long-term *** patients evaluated for FIQoL had a mean value of 2.6(range:1.0-4.1).Postoperative CCFFIS was correlated with FIQoL(Spearman’s correlation coefficient?0.854,P<0.001).Logistic regression analysis did not reveal any significant predictive variables for success of ***:Based on our criteria for success,the long-term success rate for RS over a median of 74 months is poor.

关键词： fecal incontinence redo sphincteroplasty long-term outcome

A comparison of simulation versus didactics for teaching ultrasound to Swiss medical students

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World Journal of Emergency Medicine 2019年第3期10卷 169-176页

作者： Sagar Shah steven Tohmasi Emily Frisch Amanda Anderson Roy Almog Shadi Lahham Roland Bingisser john C. Fox School of Medicine University of California Irvine USA Department of Emergency Medicine University of California Irvine Irvine USA University Hospital Basel Basel Switzerland

BACKGROUND: Point-of-care ultrasound is an increasingly common imaging modality that is used in a variety of clinical settings. Understanding how to most effectively teach ultrasound is important to ensure that medical students learn pre-clinical content in a manner that promotes retention and clinical competence. We aim to assess the effectiveness of simulation-based ultrasound education in improving medical student competence in physiology in comparison to a traditional didactic ultrasound curriculum. METHODS: Subjects were given a pre and post-test of physiology questions. Subjects were taught various ultrasound techniques via 7 hours of lectures over two days. The control group received 2 additional hours of practice time while the experimental group received 2 hours of case-based simulations. A physiology post-test was administered to all students to complete the two-day course. RESULTS: Totally 115 Swiss medical students were enrolled in our study. The mean precourse ultrasound exam score was 39.5% for the simulation group and 41.6% for the didactic group (P>0.05). The mean pre-course physiology exam score was 54.1% for the simulation group and 59.3% for the didactic group (P>0.05). The simulation group showed statistically significant improvement on the physiology exam, improving from 54.1% to 75.3%(P<0.01). The didactic group also showed statistically signifi cant improvement on the physiology exam, improving from 59.3% to 70.0%(P<0.01). CONCLUSION: Our data indicates that both simulation curriculum and standard didactic curriculum can be used to teach ultrasound. Simulation based training showed statistically signifi cant improvement in physiology learning when compared to standard didactic curriculum.

关键词： Ultrasound education POCUS Switzerland Medical education

Bloch surface eigenstates within the radiation continuum

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Light(Science & Applications) 2013年第1期2卷 113-118页

作者： Chia Wei Hsu Bo Zhen Song-Liang Chua steven G johnson john D Joannopoulos Marin Soljacic Research Laboratory of Electronics Massachusetts Institute of TechnologyCambridgeMA 02139USA Department of Physics Harvard UniversityCambridgeMA 02138USA Department of Mathematics Massachusetts Institute of TechnologyCambridgeMA 02139USA

From detailed numerical calculations,we demonstrate that in simple photonic crystal structures,a discrete number of Bloch surface-localized eigenstates can exist inside the continuum of free-space *** to the free space causes the surface modes to leak,but the forward and back-reflected leakage may interfere destructively to create a perfectly bound surface state with zero *** perform analytical temporal coupled-mode theory analysis to show the generality of such phenomenon and its robustness from variations of system ***,time-reversal invariance,two-fold rotational symmetry and a perfectly reflecting boundary are necessary for these unique states.

关键词： bound state in continuum embedded eigenvalue photonic crystal surface mode

Post-cholecystectomy symptoms were caused by persistence of a functional gastrointestinal disorder

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World Journal of Gastroenterology 2012年第12期18卷 1365-1372页

作者： Malte Schmidt Karl Sφndenaa john A Dumot steven Rosenblatt Trygve Hausken Maria Ramnefjell Gro Njφlstad Geir Egil Eide Department of Surgery Haraldsplass Deaconess HospitalBergen N-5892Norway Digestive Disease Institute Cleveland ClinicClevelandOH 44101United States Department of General Surgery Cleveland ClinicClevelandOH 44101United States Department of Internal Medicine University of BergenBergen 5021Norway Department of Pathology Haukeland University HospitalBergen 5021Norway Department of Microbiology Haukeland University HospitalBergen 5021Norway Center for Clinical Research Haukeland University HospitalBergen 5021Norway Department of Public Health and Primary Care University of BergenBergen 5021Norway

AIM： To classify gallstone disease as a basis for assessment of post-choleolstectomy symptoms.METHODS： One hundred and fifty three patients with a clinical and ultrasonographic diagnosis of gallstones filled out a structured questionnaire on abdominal pain symptoms and functional gastrointestinal disorder （FGID） before and at six months after cholecystectomy. Symptom frequency groups （SFG） were categorized according to frequency of pain attacks. According to certain pain characteristics in gallstone patients, a gallstone symptom score was accorded on a scale from one to ten. A visual analogue scale was used to quan- tify pain. Operative specimens were examined for size and magnitude of stone contents as well as presence of bacteria. Follow-up took place after six months with either a consultation or via a mailed questionnaire. Results were compared with those obtained pre-operatively to describe and analyze symptomatic outcome.RESULTS： SFG groups were categorized as severe （24.2%）, moderate （38.6%）, and mild （22.2%） attack frequency, and a chronic pain condition （15%）. Pain was cured or improved in about 90% of patients and two-thirds of patients obtained complete symptom re- lief. Patients with the most frequent pain episodes were less likely to obtain symptom relief. FGID was present in 88% of patients pre-operatively and in 57% postoperatively （P = 0.244）. Those that became asymptomatic or improved with regard to pain also had most relief from FGID （P = 0.001）. No pre-operative FGID meant almost complete cure.CONCLUSION： Only one third of patients with FGID experienced postoperative relief, indicating that FGID was a dominant cause of post-cholecystectomy symptoms.

关键词： Gallstone symptoms Functional gastrointes-tinal disease Cholecystectomy Post-cholecystectomysymptoms

National trends in resection of the distal pancreas

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World Journal of Gastroenterology 2012年第32期18卷 4342-4349页

作者： Armando Rosales-Velderrain steven P Bowers Ross F Goldberg Tatyan M Clarke Mauricia A Buchanan john A Stauffer Horacio J Asbun Department of General Surgery Mayo Clinic FloridaJacksonvilleFL 32225United States

AIM:To investigate national trends in distal pancreatectomy(DP) through query of three national patient care ***:From the Nationwide Inpatient Sample(NIS,2003-2009),the National Surgical Quality Improvement Project(NSQIP,2005-2010),and the Surveillance Epidemiology and End Results(SEER,2003-2009) databases using appropriate diagnostic and procedural codes we identified all patients with a diagnosis of a benign or malignant lesion of the body and/or tail of the pancreas that had undergone a partial or distal *** of laparoscopy was defined in NIS by the International Classification of Diseases,Ninth Revision correspondent procedure code;and in NSQIP by the exploratory laparoscopy or unlisted procedure current procedural terminology *** SEER,patients were identified by the International Classification of Diseases for Oncology,Third Edition diagnosis codes and the SEER Program Code Manual,third edition procedure *** analyzed the databases with respect to trends of inpatient outcome metrics,oncologic outcomes,and hospital volumes in patients with lesions of the neck and body of the pancreas that underwent operative ***:NIS,NSQIP and SEER identified 4242,2681 and 11 082 DP resections,***,laparoscopy was utilized in 15%(NIS) and 27%(NSQIP).No significant increase was seen over the course of the *** was performed for malignancy in 59%(NIS) and 66%(NSQIP).Neither patient Body mass index nor comorbidities were associated with operative approach(P = 0.95 and P = 0.96,respectively).Mortality(3% vs 2%,P = 0.05) and reoperation(4% vs 4%,P = 1.0) was not different between laparoscopy and open *** complications(10% vs 15%,P < 0.001),hospital costs [44 741 dollars,interquartile range(IQR) 28 347-74 114 dollars vs 49 792 dollars,IQR 13 299-73 463,P = 0.02] and hospital length of stay(7 d,IQR 4-11 d vs 7 d,IQR 6-10,P < 0.001) were less when laparoscopy was *** and two year sur

关键词： Laparoscopic distal pancreatectomy Trends Nationwide Inpatient Sample National Surgical Quality Improvement Project Surveillance epidemiology and end results

Real-world emission factors for Caterpillar 797B heavy haulers during mining operations

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Particuology 2016年第5期14卷 22-30页

作者： Xiaoliang Wang Judith C. Chow steven D. Kohl Kevin E. Percy Allan H. Legge john G. Watson Desert Research Institute 2215 Raggio Parkway Reno NV 895J2 USA Graduate Faculty University of Nevada Reno NV89503 USA The State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi'an 710075 China Wood Buffalo Environmental Association 330 Thickwood Boulevard Fort McMurray AB Canada 7DK 1 Y1 Biosphere Solutions 1610 1 lth Avenue N.W. Calgary AB Canada T2N IG9

Real-world fuel-based emission factors （EFs） from Caterpillar 797B diesel heavy haulers when used for oil sands mining operations were measured using an on-hoard portable emissions monitoring system. Average EFs （in g/kg fuel） for 16 separate tests on four trucks were 3150 ± 4 for CO2, 2.51 ± 1.30 for CH4, 10.28 ± 3.21 for CO, 0.61 ± 0.32 for non-methane hydrocarbons, 55.49 ± 9,75 for NOx （reported as NO2）, 0.70 ± 0.17 for PM2.s （mass of particles with aerodynamic diameter 〈2.5 μm）, and 0.34 ± 0.05 for black carbon （BC）. Ultrafine particle numbers averaged （4.7 ± 4.1 ） × 10^15 particleslkg fuel. Fuel-based EFs of NO, NO2, and particle numbers were higher during idling, whereas PM2.5 and BC EFs were higher during traveling without a load. A comparison of emissions with those reported by oil sands facilities showed large variations, both among the facilities and between the reported emissions and the real-world measurements.

关键词： Heavy hauler Emission Nonroad Portable emissions measurement system Mining Oil sands