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Issue Info: 
  • Year: 

    1401
  • Volume: 

    7
Measures: 
  • Views: 

    141
  • Downloads: 

    0
Abstract: 

در ریاضیات، معادله دیفرانسیل جزئی یکی از انواع معادلات دیفرانسیل است که در آن معادله شامل چند متغیر مجهول با مشتقات جزئی آن ها می باشد. این یک مورد خاص از یک معادله دیفرانسیل معمولی است. در این مقاله قصد داریم به بررسی معادله دیفرانسیل جزئی، نحوه نمایش آن، طبقه بندی و انواع آن و بررسی کاربردها در حوزه های مختلف بر اساس مقالات چاپ شده، پرداخته شود.

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Issue Info: 
  • Year: 

    1386
  • Volume: 

    18
Measures: 
  • Views: 

    430
  • Downloads: 

    0
Keywords: 
Abstract: 

مقدمه: آنزیمهای فسفودی استراز (PDEs) نقش مهمی در تنظیم سطوح درون سلولی cAMP و cGMP دارند و به یازده خانواده دسته بندی می شوند. در این مطالعه اثرات متابولیک IBMX (مهارکننده غیر انتخابی (PDE با اثر آمرینون، MC7 و MC9 (مهارکننده های انتخابی (PDE3 در موش سوری بررسی شده است. روشها: موشهای سوری (10-12 گرم) به دسته های 5 تا 10 تایی با دسترسی آزادانه به آب و غذا تقسیم و یک هفته بدون درمان (C1)، روزانه سرم فیزیولوژی (C2) یا دارو (1 mg/kg) دریافت نموده و وزن روزانه ثبت شد. در انتها موشها بیهوش و از قلب خونگیری و سرم جدا شده و در -18oC منجمد گردید. مقدار گلوکز، کلسترول و تری گلیسرید در هر نمونه اندازه گیری شد.نتایج: الگوی رشد (GP) موشهای نر و ماده فاقد تفاوت معنی دار بود. تزریق روزانه سرم فیزیولوژی بخصوص در سه روز اول موجب کاهش معنی دار رشد گردید. GP در حضور آمرینون، در مقایسه با C2، ابتدا افزایش سپس بدون تغییر و در آخر افزایش بود. IBMX تغییری در GP ایجاد نکرد. GP در حضور MC7 ابتدا بشدت کاهش و سپس به حد کنترل باز گشت، در صورتیکه اثر MC9 مشابه اثر سرم فیزیولوژی بود. IBMX موجب افزایش معنی دار کلسترول، تری گلیسرید و گلوکز شد در حالیکه آمرینون موجب کاهش معنی دار گلوکز و کلسترول گردید. Mc7 و MC9 تغییری ایجاد نکردند.نتیجه گیری: استرس موجب کاهش رشد میشود. تطابق با محیط بعد از سه روز ایجاد میشود افزایش اولیه رشد توسط آمرینون احتمالا ناشی از کاهش اثر استرس و اثر کاهنده MC7 ناشی از افزایش اثر استرس بوده است. تفاوت اثر داروها در رشد و غلظت فاکتورهای خونی نیاز به بررسی بیشتر دارد.

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Journal: 

Gene, Cell and Tissue

Issue Info: 
  • Year: 

    2017
  • Volume: 

    4
  • Issue: 

    2
  • Pages: 

    0-0
Measures: 
  • Citations: 

    0
  • Views: 

    242
  • Downloads: 

    109
Abstract: 

Dear Editor, Cyclic guanosine 3’, 5’ monophosphate (cGMP), as a second messenger, plays a key role in cell proliferation, differentiation, and apoptosis. It is formed by guanylyl cyclase (GC) from its precursor, guanosine triphosphate (GTP) (1). GC enzymes can be found in 2 major forms: soluble or cytosol form (sGC) and particulate or transmembrane form (pGC) (1).

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Issue Info: 
  • Year: 

    2015
  • Volume: 

    22
Measures: 
  • Views: 

    126
  • Downloads: 

    68
Abstract: 

INTRODUCTION: SELECTIVE PHOSPHODIESTERASE INHIBITORS (PDEI) ARE USED FOR ACUTE HEART FAILURE. HOWEVER, USING FOR LONG PERIODS, PDEIS INCREASE MORTALITY AND RESULTS IN SOME DEBATE FOR THEIR USE CLINICALLY. IN PREVIOUS STUDIES, WE SHOWED THAT DIFFERENT PDEIS PRODUCE DIFFERENTIAL…

Yearly Impact:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2012
  • Volume: 

    43
Measures: 
  • Views: 

    162
  • Downloads: 

    223
Abstract: 

IN THIS PAPER, A METHOD BASED ON FEED-FORWARD NEURAL NETWORKS IS USED TO SOLVE A CLASS OF BIHARMONIC PROBLEMS. THE TRIAL SOLUTION OF PROPOSED BIHARMONIC EQUATION IS WRITTEN AS A SUM OF TWO PARTS. THE FIRST PART SATISFIES THE BOUNDARY CONDITIONS AND CONTAINS NO ADJUSTABLE PARAMETERS. THE SECOND PART IS CONSTRUCTED SO AS NOT TO AFFECT THE BOUNDARY CONDITIONS. SECOND PART INVOLVES A FEED-FORWARD NETWORKS IS THAT TRAINED, AND CONTAINING ADJUSTABLE PARAMETERS (THE WEIGHTS).

Yearly Impact:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2007
  • Volume: 

    20
  • Issue: 

    3 (TRANSACTIONS B: APPLICATIONS)
  • Pages: 

    225-236
Measures: 
  • Citations: 

    0
  • Views: 

    433
  • Downloads: 

    183
Abstract: 

Image restoration is an essential preprocessing step for many image analysis applications. In any image restoration techniques, keeping structure of the image unchanged is very important. Such structure in an image often corresponds to the region discontinuities and edges. The techniques based on partial differential equations, such as the heat equations, are receiving considerable attention in image restoration. In this paper, a new algorithm is proposed for image restoration using partial differential equations applied on neighbors longer than one pixel. To better preserve edges in this technique, slant edges are considered in addition to vertical and horizontal edges. A number of experiments have been preformed to evaluate performance of the proposed method and to compare its performance with the existing algorithms, wiener and median filters. The results express the considerable superiority of the proposed methods.

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Issue Info: 
  • Year: 

    2008
  • Volume: 

    1
Measures: 
  • Views: 

    137
  • Downloads: 

    67
Keywords: 
Abstract: 

1. INTRODUCTIONIN THIS PAPER WE EXAMINE SOLITARY WAVE EVOLUTION FOR THE HIGHER-ORDER HIROTA EQUATIONYT+6|Y|2YX+YXXX+EH(Y)=0,E<<1,H(Y)=C1|Y|4YX+C2(Y|YX|2)X+C3Y*(YYXX)X&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP; (1)+C4Y*YXYXX+C5YYXY*XX+C6Y5XIN SOLITON PERTURBATION THEORY IS USED TO DERIVE THE DETAILS OF AN EVOLVING SOLITARY WAVE, GOVERNED BY (1). AN ANALYTICAL EXPRESSION IS FOUND FOR THE SOLITARY WAVE TAIL. AN EXCELLENT COMPARISON IS FOUND BETWEEN THE THEORETICAL AND NUMERICAL SOLUTIONS, FOR THE SOLITARY WAVE TAIL.

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Author(s): 

NEHRANI A. | KEYANPOUR M.

Issue Info: 
  • Year: 

    2015
  • Volume: 

    12
  • Issue: 

    2 (45)
  • Pages: 

    37-59
Measures: 
  • Citations: 

    0
  • Views: 

    1517
  • Downloads: 

    0
Abstract: 

The present paper considers geometric shape optimization of structures that are modelled by PDEs with random data. Random data appears in inputs and parameters of the PDE. Theoretical bases are presented, and the perturbation of the identity method is applied for transforming the shape optimization problem into a fixed domain and then formulated as a stochastic optimal control problem. Random data is taken as random fields that are approximated by Karhunen-Loeve expansion. Uncertainty quantification is performed by applying non-intrusive techniques e.g., stochastic collocation method. Gradient method is applied for optimization. Numerical result is represented in order to illustrate the applicability of the proposed method.

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Issue Info: 
  • Year: 

    2017
  • Volume: 

    20
  • Issue: 

    6
  • Pages: 

    639-647
Measures: 
  • Citations: 

    0
  • Views: 

    234
  • Downloads: 

    123
Abstract: 

Objective(s): Recently, we showed that some new synthetic compounds structurally related to cilostamide (4-(1, 2-dihydro-2-oxoquinolin-6-hydroxy)-N-cyclohexyl-N-methylbutanamide), a selective phosphodiesterase 3 (PDE3) INHIBITOR, produce inotropic effect comparable to that of IBMX (3-isobutyl-1-methylxanthine), a non-selective PDE INHIBITOR, but with differential chronotropic effect. In this investigation, we compared the pharmacological effects of these compounds as potential cardiotonic agents using the spontaneously beating atria model. Materials and Methods: In each experiment, rats were treated with reserpine. The atrium was isolated and mounted in an organ bath. We assessed chronotropic and inotropic effects using cumulative log concentration-response curves of isoprenaline alone or in combination of each test-compound. Results: Majority of test compounds augment atria contraction force (ACF) significantly but with different potencies on atrium contraction rate. Cilostamide, MCPIP ([4-(4-methyl piperazin-1-yl)-4-oxobutoxy)-4-methylquinolin-2(1H)-one]), methyl carbostyril compounds-(mc1), mc2 and mc5 increased the isoprenaline effect on ACF synergistically. But, mc6 failed to potentiate the effect of isoprenalin; mc3 and mc4 did not increase ACF, which may be because of their higher hydrophilic nature. It was interesting that mc2, alone or in combination with isoprenaline, produced the highest inotropic effect while it did not affect the basal contraction rate and almost blocked the isoprenaline chronotropic effect. Conclusion: Combination of mc2 with isoprenaline had synergistic effect on inotropic effect, but this combination reduced isoprenaline chronotropic effect; therefore, these effects cannot be related to reducing B-adrenergic receptors activity. These compounds showed different effects; probably all of them were not mediated via PDE3 inhibition and other mechanisms are involving.

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Issue Info: 
  • Year: 

    2016
  • Volume: 

    47
Measures: 
  • Views: 

    158
  • Downloads: 

    56
Abstract: 

ROSENFELD-GROBNER ALGORITHM IS A NOVEL COMPUTATIONAL TOOL IN THE CONTEXT OF DIFFERENTIAL ALGEBRA WHICH GIVES A FULL DECOMPOSITION ON THE SOLUTION SPACE OF A PARTIALLY DIFFERENTIAL EQUATION (PDE) SYSTEM. ALTHOUGH THIS ALGORITHM HAS SOME EFFICIENCIES, THERE ARE SOME PARTS YET WHICH NEED TO BE IMPROVED. IN THIS PAPER, WE FIGURE OUT SOME CRUCIAL PARTS OF THIS ALGORITHM WHICH NEED TO BE MODIFIED AND GIVE A NEW STRUCTURE TO THIS ALGORITHM MAKING IT POSSIBLE TO GIVE SOME IMPROVEMENTS. THEN WE COMPARE THE OUR RESULT BY THE PRIMITIVE VERSION OF THE ALGORITHM TO EVALUATE THE PERFORMANCE OF OUR IMPROVEMENTS. ...

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