دانشگاه صنعتی شریف،
اینجانب دوره کارشناسی را در رشته ریاضی محض در دانشگاه صنعتی شریف (1354 1359) گذراندم. از مهر ماه1361 به عنوان دانشجوی کارشناسی ارشد ریاضی وارد دانشگاه تربیت مدرس شدم. پس از اتمام دو نیمسال و انصراف از ادامه تحصیل با بورس وزارت علوم عازم کشور انگلستان شدم و دوره کارشناسی ارشد ریاضی( نظریه تکینی ) یک ساله را در دانشگاه وارویک گذراندم. برای دوره دکتری وارد دانشگاه لیدز شدم و دکتری خود را پس از سه سال گرفتم.در آذر ماه 1367 به ایران برگشتم و تا پایان سال 1367 به عنوان عضو هیات علمی پیمانی در دانشگاه صنعتی شریف خدمت کردم. به دلیل بورسیه بودن به دانشگاه تربیت مدرس فراخوانده شدم و از فروردین ماه سال 1368 در این دانشگاه مشغول به خدمت شدم که هم اکنون نیز ادامه دارد.
Chen conjecture states that every Euclidean biharmonic submanifold is minimal. In this paper we consider the Chen conjecture for -operators. The new conjecture (-conjecture) is formulated as follows: If then where is an isometric immersion of a Riemannian manifold into the Euclidean space , is the -th mean curvature of , and is the linearized operator of the -th mean curvature of the Euclidean hypersurface . We prove the -conjecture for the hypersurface with at most two principal curvatures.
BACKGROUND Various trials have reported improved outcomes for adolescents and young adults (AYAs) with acute lymphoblastic leukemia (ALL) who received treatment with pediatric‐based regimens. Those reports prompted the current investigation of the pediatric augmented Berlin‐Frankfurt‐M?nster (ABFM) regimen in AYA patients. The results were compared with those from a similar population that received the hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone (hyper‐CVAD) regimen. METHODS Eighty‐five patients ages 12 to 40 years who had Philadelphia chromosome (Ph)‐negative ALL received the ABFM regimen from October 2006 through April 2012. Their outcome was compared with outcomes in 71 historic AYA pati
It was shown that the physical filler-polymer and filler–filler interactions, apart from the filler surface chemistry, has a substantial role in controlling the vulcanization kinetics of styrene butadiene rubber filled with nano-silica in a sulfur vulcanization system. Kinetic studies by the oscillating disc rheometer, differential scanning calorimeter, and swelling tests revealed that the vulcanization rate goes through a maximum as loading of silica increases, but conversion in crosslinking continuously decreases as the amount of silica increases. The effect of silica loadings on the vulcanization reactions was linked to the immobilization of rubber chains around particles as well as in a polymer-mediated filler network, which were diff
The use of Silybum marianum leaves extract as a 304 stainless steel corrosion inhibitor in 1.0?M HCl solution was investigated by weight loss measurements, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods. Potentiodynamic polarization curves indicated that S. marianum extract behaves as mixed-type inhibitor. The adsorption of the extract constituents was further discussed in view of Langmuir adsorption isotherm. The effect of temperature on the inhibition efficiency was studied. Quantum chemical parameters were also calculated, which provided reasonable theoretical explanation for the adsorption and inhibition behavior of S. marianum extract on the 304 stainless steel.
Serum cystatin C can improve glomerular filtration rate (GFR) estimation over creatinine alone, but whether this translates into clinically relevant improvements in drug dosing is unclear. This prospective cohort study enrolled adults receiving scheduled intravenous vancomycin while hospitalized at the Mayo Clinic in 2012. Vancomycin dosing was based on weight, serum creatinine with the Cockcroft-Gault equation, and clinical judgment. Cystatin C was later assayed from the stored serum used for the creatinine-based dosing. Vancomycin trough prediction models were developed by using factors available at therapy initiation. Residuals from each model were used to predict the proportion of patients who would have achieved the target trough with
Transformative technologies for producing renewable energy have promising features for substantial reductions in carbon emissions and environmental footprints of the building sector. Investments in renewable energy systems require substantial implementation costs followed by a long period of recovering the invested capital through savings in utilities bills. Favorable timing of renewable energy system implementation can reduce capital expenses and enhance returns on investments. An appropriate investment valuation method is needed to identify the appropriate time to implement any given renewable energy system and to find the values of properly scheduled investments. Real options analysis provides the ability to cope with investment timing u
Bone matrix consists of two major phases at the nanoscale: organic and hydroxyapatite. Nanotechnology as a diverse and interdisciplinary area of research has the capacity to revolutionise many areas of applications such as bone tissue engineering. Nanohydroxyapatite/gelatin composite has higher osteoblast attachment and proliferation than micro‐sized ones, and shorter culturing period and lower cell seeding density compared to pure gelatin. A nanostructured scaffold was fabricated by three methods for bone repair using nanohydroxyapatite and gelatin as the main components. Its biocompatibility, alizarin red test on the 14th and 21st days, gene expression on the 21st day in in vitro using and histomorphometry after 4 and 8 weeks post‐i
We study connected orientable spacelike hypersurfaces x: Mn→ Mn+ 1 q (c), isometrically immersed into the Riemannian or Lorentzian space forms of curvature c=− 1, 0, 1, and index q= 0, 1, satisfying the condition Lkx= Ax+ b, where Lk is the linearized operator of the (k+ 1) th mean curvature Hk+ 1 of the hypersurface for a fixed integer 0≤ k< n, A is a constant matrix and b is a constant vector. We show that the only hypersurfaces satisfying that condition are hypersurfaces with zero Hk+ 1 and constant Hk (when c= 0), open pieces of totally umbilic hypersurfaces and open pieces of the standard Riemannian product of two totally umbilic hypersurfaces.
We aimed to assess the role of a short duration multimedia workshop to improve the knowledge and skills in cardiac critical care ultrasonography. Thirty critical care physicians participated in the cardiac critical care ultrasonography workshop. Two weeks prior to hands-on training, a three-hour web-based didactic lecture was provided to learners. Hands-on training consisted of a two-hour examination on models without pathology and a 30-minute debriefing with instructors. Pre- and post-workshop knowledge tests were conducted online using 30 multiple choice questions. Pre- and post-workshop skill tests were video captured for evaluation by two reviewers to whom data were masked. Scores were based on 34 predetermined checklist items including
We study some ????????-finite-type Euclidean hypersurfaces. We classify ????????-1-type Euclidean hypersurfaces and ????????-null-2-type Euclidean hypersurfaces with at most two distinct principal curvatures. We also prove that, under some mild restrictions, there exists no ????????-null-3-type Euclidean hypersurface.
Background:The stapled hemorrhoidopexy (SH) is a procedure for prolapse and hemorrhoids. At first SH seemed to be a good alternative for the Milligan Morgan (MM) hemorrhoidectomy and preliminary results in early 2000 confirmed it. However, further studies and evaluation of long-term results showed poorer outcomes.Objectives:This study aimed to evaluate and compare the results of these 2 surgical procedures in terms of recovery, improvement of symptoms and incidence of complications.Materials and Methods:This study was conducted from April 2008 to August 2010. A total of 80 patients were divided into 2 groups of 40 each. In the SH group, there were 24 males (60%) and 16 females (40%) with a mean age of 48?12.5 yrs. In the MM group, there wer
PurposeTo execute an evidence-based review answering the following question: “Among patients receiving dental implants, do those who receive perioperative antibiotic therapy, compared with those who do not, have a decreased likelihood of implant failure?”Materials and MethodsWe performed a literature review. The primary predictor variable was an antibiotic regimen, which was grouped into 3 categories: a single preoperative dose, a single preoperative dose and multiday postoperative therapy, and no antibiotic therapy. The primary and secondary outcome variables were implant failure and postoperative infection, respectively.ResultsEight studies meeting the inclusion criteria were reviewed. Two studies assessed the effect of a single preop
Buttonhole cannulation is a method of cannulation of native arteriovenous fistulae traditionally practiced by self‐cannulators. At St Michael's Hospital, this method has been modified to allow its use in problematic fistulae by multiple cannulators. In a busy dialysis unit, the need for a few specific cannulators to establish the tunnel tracks in combination with the variable dialysis schedules creates logistical challenges. A new method of creating tunnel tracks with the use of the BioHole™ device was evaluated. Buttonhole tracks were created in 12 patients using a peg of polycarbonated material with a holder (BioHole™ kit). The peg was inserted into the path left by the hemodialysis sharp needle following the index cannulation. Fou
Sulfur mustard (2,2-dichlorodiethyl sulfide: SM), the protagonist of vesicant chemical weapons, was first used in July 1917. Despite prohibition of its production and use by international conventions, it has been used in several conflicts. More than 100,000 soldiers and civilians were injured due to SM exposure during Iran–Iraq war (1980–1988). The acute skin lesions consist of erythema, edema, and blisters. Skin xerosis and pruritus, pigmentation disorders, scars, and cherry angiomas are among the most common long-term skin lesions after contact with SM. Although SM is a well-known carcinogenic substance, skin cancers are rarely reported.
Materials and Methods: A total of 36 paraffin-embedded blocks (25 males and 11 females) with primary diagnosis of non-Hodgkin lymphoma were studied by immunohistochemical markers according to cellular morphology.Results: The frequencies were diffuse large B-cell (41.1%), low-grade B-cell (35.2%), peripheral T-cell (11.7%), Burkitt (5.8%), and Hodgkin lymphomas (5.8%). The involved sites were salivary gland (26.4%), maxillary bone (23.5%), mandibular soft tissues (17.6%), maxillary sinus (14.7%), mandibular bone (8.8%), tonsils and tongue (5.7%), and lip and vestibule (2.9%), and 2 cases (5.5%) turned out to be undifferentiated carcinomas. The most common lymphomas in male and females were diffuse large B-cell and low-grade B-cell lymphomas,
In this paper we study cohomogeneity one Minkowski space R-1(n). Among other results, we prove that the orbit space is homeomorphic to R or [0, infinity). We show that if there is a spacelike principal orbit, then each of the orbits is spacelike and principal. If n = 3 and there is a singular orbit, we characterize the orbits up to isometry, and the acting group up to conjugacy.
We study cohomogeneity one anti de Sitter space H 3 1. When the action is proper we determine the orbits up to isometry and the acting groups up to conjugacy.
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