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GLOBAL DYNAMICS OF A DIFFERENTIAL SUSCEPTIBILITY MODEL

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International Journal of Biomathematics 2012年第5期5卷 219-238页

作者： M. R. razvan S. YASAMAN Sharif University of TechnologyDepartment of Mathematical SciencesP. O. Box 11155-9315 Tehran Iran School of MathematicsInstitute for Research in Fundamental Sciences ( IPM) P. O. Box 19395-5746 Tehran Iran

An SIS epidemiological model in a population of varying size with two dissimilar groups of susceptible individuals has been analyzed. We prove that all the solutions tend to the equilibria of the system. Then we use the Poincar~ Index theorem to determine the number of the rest points and their stability properties. It has been shown that bistability occurs for suitable values of the involved parameters. We use the perturbations of the pitchfork bifurcation points to give examples of all possible dynamics of the system. Some numerical examples of bistability and hysteresis behavior of the systeIn has been also provided.

关键词： Epidemiological model differential susceptibility disease-free equilibrium endemic equilibrium Poincar~ index bifurcation.

Difficulties in diagnosing anorectal melanoma: A case report and review of the literature

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World Journal of Clinical Cases 2021年第36期9卷 11369-11381页

作者： Raluca Cristina Apostu Elena Stefanescu Radu razvan Scurtu Gabriel Kacso Radu Drasovean Department of Surgery "Iuliu Hatieganu"University of Medicine and PharmacyCluj-Napoca 400006Romania Department of Anesthesia and Intensive Care Emergency County Clinical HospitalCluj-Napoca 400006Romania Department of Surgery University of Medicine and Pharmacy"Iuliu Hatieganu"Cluj-NapocaCluj Napoca 400006Romania Department of Medical Oncology and Radiotherapy “Iuliu Hatieganu”University of Medicine and PharmacyCluj-Napoca 400006Romania

BACKGROUND Anorectal melanoma is a tumour that is difficult to identify due to its rarity and variability of *** data published in the literature do not allow for diagnostic and treatment guidelines to be *** melanoma has the worst prognosis among mucosal melanomas and is frequently misdiagnosed by standard identification *** SUMMARY A 66-year-old woman presented with intermittent anal bleeding,pain,and tenesmus in the past month,with no associated weight *** revealed a cauliflower-like tumour with a diameter of 1.5 cm,with exulcerated areas and an adherent clot but without *** results identified an inflammatory rectal polyp with nonspecific chronic *** markers CA 19-9 and CEA were within the normal *** 6 mo,due to the persistence of symptoms,a pelvic magnetic resonance imaging scan was performed.A lesion measuring 2.8 cm×2.7 cm×2.1 cm was identified at the anorectal junction,along with two adjacent *** distant metastases were *** was performed on the second set of biopsies,and a diagnosis of anorectal melanoma was *** treatment by abdominoperineal resection was *** was marked by the appearance of lung metastases at 1 mo postoperatively,detected on a positron emission tomography-computer tomography scan,and perineal recurrence after 5 *** molecular testing,the patient was included in an immunotherapy *** This case highlights the difficulty of establishing a definitive early diagnosis of anorectal melanoma,the importance of performing histological analysis on a wellrepresented biopsy specimen,and the poor prognosis,even with radical surgery.

关键词： Mucosal melanoma Anorectal Immunohistochemistry Melanocytes Molecular targeted therapy Case report

飞秒激光诱导金属钨表面周期性自组织结构的研究

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光学学报 2016年第5期36卷 312-318页

作者：李晨程光华 Stoian razvan 中国科学院西安光学精密机械研究所瞬态光学与光子技术国家重点实验室陕西西安710119 中国科学院大学北京100049 Laboratoire Hubert Curien UMR 5516 CNRSUniversite de LyonUniversite Jean MonnetSaint Etienne France 42000

飞秒激光诱导金属表面周期性自组织微纳米条纹结构,在调控热辐射源、摩擦、超亲水性、超疏水性和打标等方面具有广泛的应用前景.研究了800nm飞秒激光诱导金属钨表面周期性自组织结构的形成规律和形成机理.采用Sipe干涉模型和有限时域差... 详细信息

飞秒激光诱导金属表面周期性自组织微纳米条纹结构,在调控热辐射源、摩擦、超亲水性、超疏水性和打标等方面具有广泛的应用前景.研究了800nm飞秒激光诱导金属钨表面周期性自组织结构的形成规律和形成机理.采用Sipe干涉模型和有限时域差分法,仿真了第1个飞秒激光脉冲刻蚀后随机粗糙表面引起的激光电磁场能量表面分布和第20个脉冲后低空间频率条纹结构引起的激光电磁场能量表面分布.揭示了低空间频率条纹与高空间频率条纹的形成机理,考察了表面微观形貌的演化和条纹周期随着脉冲增多而递减的现象.

关键词：超快光学飞秒激光微加工钨有限时域差分法

Deliberate external pancreatic fistula after pancreaticoduodenectomy performed in the setting of acute pancreatitis, and its internalization through fistula-jejunostomy

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Hepatobiliary & Pancreatic Diseases International 2020年第1期19卷 94-96页

作者： Sorin T Alexandrescu Andrei C Zlate razvan T Grigorie Mihnea Ionescu Irinel Popescu Fundeni Clinical Institute Dan Setlacec Centre of General Surgery and Liver TransplantationSos.Fundeni nr.258sector 2BucharestRomania Carol Davila University of Medicine and Pharmacy BucharestRomania Titu Maiorescu University Faculty of MedicineBucharestRomania

To the Editor:Many patients with tumors of the pancreatic head or of the ampulla of Vater require endoscopic manipulation of the duodenal papilla in order to achieve tumor biopsy or for common bile duct *** interventional endoscopy approaches may lead to acute *** iatrogenic acute pancreatitis will influence the surgical strategy in patients scheduled for pancreaticoduodenectomy(PD).Due to the small number of cases,the surgical strategy in patients who require PD in the context of acute pancreatitis has not been standardized.

关键词： pancreatitis acute Vater

Timing of paracentesis and outcomes in hospitalized patients with decompensated cirrhosis

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World Journal of Hepatology 2020年第12期12卷 1267-1275页

作者： Cristina Tocia Andrei Dumitru Luana Alexandrescu razvan Popescu Eugen Dumitru Department of Gastroenterology Constanta County Clinical Emergency HospitalConstanta 900647Romania Department of General Surgery Constanta County Clinical Emergency HospitalConstanta 900647Romania

BACKGROUND Ascites is one of the most common complications of cirrhosis,placing a significant burden on the healthcare *** regarding the optimal time of paracentesis and outcomes among patients with cirrhosis and ascites are *** To assess the outcomes of patients who underwent paracentesis within 12 h after admission compared to patients who underwent paracentesis later than 12 *** The study included 185 patients with cirrhosis and ascites who underwent *** early paracentesis group was defined as paracentesis performed12 h after admission(120 patients).Newonset complications of cirrhosis,length of hospital stay,weekday or weekend admission,in-hospital mortality rate,and 90-d readmission rates were assessed and compared between the *** Significantly more patients in the delayed paracentesis group than in the early paracentesis group developed hepatic encephalopathy(45%vs 21.5%,P<0.01),hepato-renal syndrome(21.6%vs 9.2%,P=0.03)and infections(25%vs 10.7%,P=0.02)during *** were no statistically significant differences in the occurrence of spontaneous bacterial peritonitis and upper gastrointestinal bleeding between the two *** of stay was shorter in the early paracentesis group than in the delayed paracentesis group(6.7 d vs 12.2 d)and inhospital mortality was lower among patients in the early paracentesis *** in the delayed paracentesis group had a higher risk of developing complications during *** Early paracentesis(within 12 h after admission)could be a new inpatient quality metric among patients hospitalized with cirrhosis and ascites as it is associated with fewer complications of cirrhosis,lower in-hospital mortality and shorter length of stay.

关键词： Cirrhosis Ascites Hepatic encephalopathy Spontaneous bacterial peritonitis Early paracentesis Delayed paracentesis

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超短脉冲激光诱导周期性表面结构（英文）

中国光学 2018年第1期11卷 1-17页

作者：李晨 STOIAN razvan 程光华法国里昂大学让莫内大学法国国家科学研究中心休伯特居里实验室法国圣埃蒂安市42000 中国科学院西安光学精密机械研究所瞬态光学与光子技术国家重点实验室陕西西安710119 陕西科技大学机电工程学院陕西西安710012

激光诱导周期性表面结构(Laser-induced periodic surface structures,LIPSS)具有纳米尺度的特征结构和自重复的微观尺度的排列图案,因此,LIPSS在传感器、太阳能发电、光催化等方面具有广泛的应用前景。本文首先介绍LIPSS形成过程中超... 详细信息

激光诱导周期性表面结构(Laser-induced periodic surface structures,LIPSS)具有纳米尺度的特征结构和自重复的微观尺度的排列图案,因此,LIPSS在传感器、太阳能发电、光催化等方面具有广泛的应用前景。本文首先介绍LIPSS形成过程中超快激光与物质相互作用的复杂过程,强调瞬态光学性质和表面结构变化的作用。然后综述几种具有代表性的LIPSS形成机理,并且讨论了各自的优缺点。接着介绍了LIPSS形成过程中材料的变化,主要包括材料化学成分、晶体结构和表面微观结构的变化。最后综述了LIPSS在材料表面处理、光学和机械等方面的应用。

关键词：超快光学飞秒激光微加工周期性表面结构

Unsteady shock front waviness in shock-buffet of transonic aircraft

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Advances in Aerodynamics 2020年第1期2卷 182-198页

作者： razvan Marian Apetrei Vlad Ciobaca Jose Luis Curiel-Sosa Ning Qin Department of Mechanical Engineering The University of SheffieldSheffieldUK DLR Institute of Aerodynamics and Flow TechnologyBraunschweigGermany

The unsteady transonic aerodynamics of a wing-body configuration is investigated by solving the Unsteady Reynolds-averaged Navier-Stokes equations closed with the full Reynolds Stress *** work presents the prediction of flow field characteristics during deep shock-buffet penetration of a transport aircraftrepresentative *** number of 0.85,and Reynolds number of 5 million based on the mean chord,are selected to reproduce experimental test conditions that serve as validating *** results obtained give information about both surface and flow field shock-buffet *** unsteady shock front is observed on the suction side of the wing which gives birth to the so-called buffet *** field characteristics are dominated by the presence of lambda-shaped shocks and fully separated boundary layer over a significant part of the wing.

关键词： Aerodynamics CFD Shock-buffet

Influence of hepatitis viruses on clinico-pathological profiles and long-term outcome in patients undergoing surgery for hepatocellular carcinoma

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Hepatobiliary & Pancreatic Diseases International 2014年第2期13卷 162-172页

作者： Anna-Maria Tanase Traian Dumitrascu Simona Dima razvan Grigorie Agnes Marchio Pascal Pineau Irinel Popescu Center of General Surgery and Liver Transplant Fundeni Clinical Institute Unité "Organisation nucléaire et oncogenèse" INSERM U993Institut

BACKGROUND: The global risk of hepatocellular carcinoma(HCC) is largely due to hepatitis B virus (HBV) and hepatitis C virus (HCV) infections. In recent years, however, an increased prevalence of non-viral HCC has been noted. The clinical impact of the presence/absence of viral infections in HCC remains controversial. The present study aimed to assess the effect of hepatitis viruses on demographics, clinical and pathological features and long-term outcome in a large cohort of Romanian patients who underwent surgery for HCC. METHODS: The study included 404 patients with HCC who had undergone resection, transplantation or radiofrequency ablation at a single institution between 2001 and 2010. The patients were divided into four groups: 85 patients with hepatitis B virus infection (HBV group), 164 patients with hepatitis C virus infection (HCV group), 39 patients with hepatitis B and C virus co-infection (HBCV group), and 116 patients without viral infection (non-BC group). RESULTS: The patients of both HBV (56.0±11.3 years) and HBCV groups (56.0±9.9 years) were significantly younger than those of the HCV (61.0±8.5 years, P=0.001) and non-BC groups(61.0±13.0 years, P=0.002). Interestingly, the prevalence of liver cirrhosis was significantly lower in the non-BC group (47%)than in any other subsets (72%-90%, P<0.002). Furthermore, the non-BC patients were more advanced according to the Barcelona Clinic Liver Cancer stages than the patients of the HCV or HBCV groups (P<0.020); accordingly, they were more frequently assessed beyond the Milan criteria than any other groups (P=0.001). No significant differences in the disease-free or overall survival rates were observed among these groups. CONCLUSIONS: Patients with non-viral HCC are diagnosed at advanced ages and stages, a situation plausibly due to the poor effectiveness of cancer surveillance in community practice. The presence of viral infections does not appear to impair the longterm prognosis after surgical treatm

关键词： hepatitis B virus hepatitis Cvirus hepatocellular carcinoma recurrence prognosis

Aggressive surgical approach in patients with adrenal-only metastases from hepatocellular carcinoma enables higher survival rates than standard systemic therapy

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Hepatobiliary & Pancreatic Diseases International 2021年第1期20卷 28-33页

作者： Sorin T Alexandrescu Adina E Croitoru razvan T Grigorie Dana R Tomescu Gabriela Droc Mugur C Grasu Irinel Popescu Dan Setlacec Centre of General Surgery and Liver Transplantation Fundeni Clinical InstituteBucharest 022328Romania Carol Davila University of Medicine and Pharmacy Bucharest 020021Romania Department of Oncology Fundeni Clinical InstituteBucharest 022328Romania Faculty of Medicine Titu Maiorescu UniversityBucharest 031593Romania Dan Tulbure Centre of Anesteziology and Intensive Care Fundeni Clinical InstituteBucharest 022328Romania Department of Radiology Fundeni Clinical InstituteBucharest 022328Romania

Background:Although guidelines recommend systemic therapy even in patients with limited extrahepatic metastases from hepatocellular carcinoma(HCC),a few recent studies suggested a potential benefit for resection of extrahepatic ***,the benefit of adrenal resection(AR)for adrenal-only metastases(AOM)from HCC was not proved *** is the first study to compare long-term outcomes of AR to those of sorafenib in patients with AOM from ***:The patients with adrenal metastases(AM)from HCC were identified from the electronic records of the institution between January 2002 and December *** who presented AM and other sites of extrahepatic disease were ***,the patients with AOM who received other therapies than AR or sorafenib were ***:A total of 34 patients with AM from HCC were *** of these,22 patients had AOM,6 receiving other treatment than AR or ***,8 patients with AOM underwent AR(AR group),while 8 patients were treated with sorafenib(SOR group).The baseline characteristics of the two groups were not significantly different in terms of age,sex,number and size of the primary tumor,timing of AM diagnosis,Child-Pugh and ECOG *** a median follow-up of 15.5 months,in the AR group,the 1-,3-,and 5-year overall survival rates(85.7%,42.9%,and 0%,respectively)were significantly higher than those achieved in the SOR group(62.5%,0%and 0%at 1-,3-and 5-year,respectively)(P=0.009).The median progression-free survival after AR(14 months)was significantly longer than that after sorafenib therapy(6 months,P=0.002).Conclusions:In patients with AOM from HCC,AR was associated with significantly higher overall and progression-free survival rates than systemic therapy with *** results could represent a starting-point for future phase II/III clinical trials.

关键词： Adrenal metastases Hepatocellular carcinoma Adrenal resection Sorafenib Survival