modern research physics

---

A direct method to determine numerical solutions of linear Volterra integro-differential equations is presented in this paper.. This method is based on block-pulse functions and its operational matrix. By using this approach, the integro-differential equation reduces to a linear lower triangular system of algebraic equations which can be solved easily. Some numerical examples are provided to illustrate accuracy and computational efficiency of the method. MSC: 45J05 41A30

---

In this note we introduce the notion of weak McCoy rings as a generalization of McCoy rings, and investigate their properties. Also we show that, if is a semi-commutative ring, then is weak McCoy if and only if is weak McCoy.

---

An efficient one-pot synthesis of 1,8-dioxo-octahydroxanthene is achieved through a condensation of arylaldehydes and 5,5-dimethyl-1,3-cyclohexanedione in the presence of N-bromosuccinimid. This method enjoys several advantages such as low cost, simple work up procedure and safe reaction conditions. Graphical Abstract Table 1. Optimization of reaction condition. Entry Amount of NBS Condition Yield (%)a 1 0 mol % Reflux/ethanol/20 h 0 2 2 mol % 50°C/ethanol/12 h tr 3 2 mol % Reflux/ethanol/14 h 15 4 5 mol % Reflux/ethanol/14 h 30 5 10 mol % Reflux/ethanol/14 h 55 6 15 mol % Reflux/ethanol/14 h 80 7 20 mol % Reflux/ethanol/14 h 94 8 20 mol % MW/DMAC/5 min 90 a Isolated yield.

---

در این مقاله یک روش عددی مناسب برای حل معادلات انتگرال- دیفرانسیل فردهلم غیر خطی با تأخیر زمانی ارائه شده است. روش مبتنی بر بسط تیلور می باشد. این روش معادله انتگرال- دیفرانسیل و شرایط داده شده را به معادله ماتریسی که متناظر با یک دستگاه از معادلات جبری غیر خطی با ضرایب مجهول بسط تیلور می باشد تبدیل می کند، که از حل دستگاه، ضرایب بسط تیلور تابع جواب به دست می آید. سپس با مثال هایی کارایی روش را ارزیابی می کنیم.

---

Fe Doped CdS nanopaqrticles have been synthesized by a wet chemical method and TG used as a capping agent. The particle size of the nanoparticles calculated from XRD and optical methods has been found in the range 3-5 nm. The x-ray diffraction measurements showed that the nanoparticles have the structure of hexagonal phase. The broadening of XRD patterns indicate that the prepared CdS:Fe samples are nanostructures. The UV absorption results indicated that the doping increased optical band gap of nanoparticles which means the particle size decreased due to Fe doping. Also, effects of doping and capping agent concentration on the luminescence spectra of CdS:Fe nanoparticles investigated

---

This article is a report of calculation and measurements of a p+-n InSb photo-diode leakage current fabricated by mesa on the basis of the calculation and measurement of different leakage currents in InSb photo-diode along with its variation it shows that at relatively low reverse biases (up to about 300 mV) G-R and shunt current are dominant. But at high reverse biases the tunneling current dominates. In this article we investigate the relation between device parameters and rate of leakage currents and investigated this relation by fabricating high quality p+-n diode

---

Biosurfactants are products of broad range of microorganisms. These compounds are surface active. Glycolipids, Phospholipids & Fatty acids, Lipopeptids and Lipoproteins, Polymeric biosurfactants and Special Biosurfactants are main types of biosurfactants. Rhamnolipid is a type of Glycolipids that is produced by Pseudomonas aeruginosa. In the present paper, P. aeruginosa MM1011 was obtained from Persian Type Culture Collection (Biotechnology Center, IROST). The aim of this investigation was optimization of mineral salts medium with sugar beet molasses to produce rhamnolipid considering specific parameters. such as: C/N, Temperature, pH, shaking rate, and Inoculation size. Since P. aeruginosa is Suc.(-), it was mutated to be able to use the sucrose as carbon source. The molasses treated chemically, then used by the bacterium. The results assayed by phenol-sulfuric acid method, and crude oil emulsification capability. Results of ANOVA. Depicted results showd that the optimum conditions without molasses is: temp.:33˚c, pH 7, C/N:18, shaking rate: 200 rpm and inoculom: 2% in 96 hours and the best medium is 3M which contained sugar beet molasses. Further investigation proved that the best production temperature is 33°c when pH is 6.8, shaking rate: 200 rpm, C/N: 16, inoculom: 2%. Using the above mentioned factors, the obtained results showed that the produced rhamnose was 0.22 g/L (rhamnolipid = 0.66 g /L) and crude oil emulcification was 55.5 %.

---

In this paper, we study the left and right weak topological centers of the second dual of Banach algebra A and we establish some relationships of them with the Arens regularity of A.

---

We introduce quasi-cofaithful ideals which is a generalization of cofaithful ideals, and investigate their
properties. We say a faithful ideal $I$ is textit{quasi-cofaithful} if $I$ contains a finitely generated
faithful ideal $I_1$. We show that every faithful ideal of $R$ is quasi-cofaithful if and only if every faithful ideal of $M_n(R)$ is quasi-cofaithful. We show that if $R$ has the descending chain condition on right annihilators of right ideals, then each faithful ideal of $R$ is quasi-cofaithful. For a u.p.-monoid $M$, it is shown that if $R$ is a quasi-Baer ring, then each faithful ideal of $R$ is quasi-cofaithful if and only if each faithful ideal of monoid ring $R[M]$ is quasi-cofaithful.

---

In this research, we are going to study of QCD penguin structure and calculated the second order approximation. The amplitude of decays related to QCD penguin in quark model up to the first and second orders calculated. We calculated the amplitude of QCD penguin on lowest order of for first order of the decay processes and for second order of the decay processes . We calculated the decay rates of the first and second order of QCD penguin for various b quark decays. We consider that, the second order of QCD penguin of b quark decays is much smaller than the first order of them. In the other hand, we can ignore the second order of QCD penguin in the b quark decays. We deduced various two and three body decays of B meson decays from various decays of b quark model. We compared the branching ratios of various decays of B meson, theoretically and experimentally and saw that the second order of QCD penguin term in b quark decays is small.

---

Four Branchinecta orientalis populations from different parts of West Azarbaijan were compared using morphometric and ecological characteristics. Filed studies showed that, B. orientalis widely distributed in the lagoons around the Urmia Lake and also Northern regions of province. The discriminant function analysis based on morphological characteristics (12 in female and 10 male) measurements showed that there are significant differences between the studied populations, where 96 % of males, 91 % of females and cumulatively 85.3% of original grouped cases were correctly classified. As a general result, it may be concluded that discriminant function analysis using male morphological characters is a powerful tool in discrimination of populations under study.

---

Some of ruderal and segetal areas inside of Hamedan city and its suburb (in a radius of 2o km) involving some of farms, gardens, green spaces, waste lands and also margin of terrific regions (streets and superhighways) were compared based on ecological-floristically view in relation to presence and dispersal of Heliotropium genus between 2010 -2011. This genus with 74 species is introduced as one of the Boraginaceae family genus for Iran, which have many species. Heliotropium europaeum L and Heliotropium noëanum Boiss. have been already observed in inside of Hamedan city and its suburb. Extensive dispersal of H. europaeum L. species with H 4, 5, 6 hemeroby degrees as an segetal-ruderal neophyte element, in humid areas (such as gardens, left farm lands, beside roads) and also in dry regions (such as between pavings and asphalts clef, beside of walls and etc.) indicates high adaptation of this species with many ruderal biotops inside of Hamedan city and its suburb. H. noëanum Boiss. with H4 hemeroby degree, was observed limitedly and only in one urban site and also in a few number in its suburb.

---

هدف اصلی در این مقاله حل معادلات انتگرال- دیفرانسیل فردهلم خطی با تأخیر زمانی از مراتب بالا است. روش مبتنی بر بسط لژاندر با استفاده از نقاط هم محلی گاوس- لژاندر می باشد. در این روش سری لژاندر قطع شده جواب معادله را در نظر گرفته و معادله انتگرال- دیفرانسیل خطی و شرایط داده شده را به یک معادله ماتریسی تبدیل می کنیم، سپس با استفاده از نقاط هم محلی گاوس- لژاندر، معادله ماتریسی تبدیل به یک دستگاه از معادلات جبری خطی با ضرایب مجهول بسط لژاندر می شود که از حل دستگاه، ضرایب بسط لژاندر تابع جواب به دست می آید. در آخر کارایی روش را با مثال هایی مورد تجزیه و تحلیل قرار می دهیم.

---

Spatial generalized linear mixed models are usually used for modeling non-Gaussian and discrete spatial responses. In these models, spatial correlation of the data can be considered via latent variables. Estimation of the latent variables at the sampled locations, the model parameters and the prediction of the latent variables at un-sampled locations are of the most important interest in SGLMM. Often the normal assumption for latent variables is considered just for convenient in practice. Although this assumption simplifies the calculations, in practice, it is not necessarily true or possible to be tested. In this paper, a closed skew normal distribution is proposed for the spatial latent variables. This distribution includes the normal distribution and also remains closed under linear conditioning and marginalization. In these models, likelihood function cannot usually be given in a closed form and maximum likelihood estimations may be computationally prohibitive. In this paper, for maximum likelihood estimation of the model parameters and predictions of latent variables, an approximate algorithm is introduced that is faster than the former method. The performance of the proposed model and algorithm are illustrated through a simulation study.

---

The volcano - sedimentary complex in the North of Shahrekord , center of Chahar mahal and bakhtiary province as a NW-SE trend belt has located in the central part of the Sanandaj- Sirjan structural zone is composed of volcanics (basalts, andesitic basalts and andesites),subvolcanics (dolerites and microdiorites), volcaniclastics (tuffs, lapilli tuffs, agglomerates, volcanic breccia and tuffites) belong to Upper Jurassic, Middle Kimmerian orogenic phase. These rocks with calc-alkaline to tholeiitic affinity were erupted in a subduction environment as island arc.
The above mentioned lithological unites have been affected by hydrothermal fluids with pH=8-9, T=226◦C(in intermediate argillic zone) to 300◦C (in quartz- epidote veins) under 200 bar pressure. The secondary minerals have replaced primary rock components (selective pervasive) or have occurred as vein and vesicle fillings (non pervasive). There are three alteration zones in the study area including propylitic (chloritic), sericitic and intermediate argillic based on variety amounts of the chlorite, epidote, clinozoisite, calcite and illite. Vesicles in basalts are filled by chlorite-epidote-clinozoisite-calcite- quartz assemblages too. The investigation of mass changes show that the volcanic rocks have lossed their mass as result of hydrothermal alteration partially in chloritic zone. CaO enrichment and Na2O depletion in chloritic zone, Na2O, K2O depletion and MgO enrichment in sericitic zone, FeO, Na2O, K2O enrichment in intermediate argillic zone are key indices to determination of fossil alteration zones.
.

---

The Alut granitoid complex is located in the northwestern part of the Sanandaj–Sirjan zone. This complex comprises three main units i.e. monzogranite to granodiorite bodies (SiO2 = 65–77 wt %) which is widespread throughout the area, a quartz-diorite to tonalite unit (SiO2 = 52–63 wt %) exposed as two stocks and mylonitic granitoid scattered as separate outcrops through the area. NE-SW trending microquartz-diorite and NW-SE trending aplite dykes are also present in this complex. The quartz-diorite to tonalite unit has relatively high CaO,FeO, MgO, Al2O3 and low Rb/Sr, Sr/Y, and (La/Yb)N, which preclude an origin of variably fractionated mantle melts and favour a mafic lower crustal source. Dehydration melting of biotite-bearing metasedimentary sources at relatively low pressures is proposed for the origin of monzogranite to granodiorite unit. Geochemically this complex is metaluminous to slightly peraluminous, typical of I-type granites. It belongs to low K (and high K for some monzogranite samples) calc-alkaline series and displays the geochemical characteristics typical of volcanic arc plutons related to an active continental margin area (e.g. significant Nb, Ti, P and Sr depletion). Based on collected geochemical data, the Alut granitoids originated by partial melting of crustal protoliths having different compositions in a deformed active margin.

---

In this study, gammaruses were collected from southern coast of Caspian Sea in Bandar Anzali. Samples were divided into three groups control, dried and frozen. These treatments were examined with several experiments such as protein, fat, sah and moisture in three time after a week, two weeks and a month in three replications. The results showed that the Analyze- Variance among the groups had significant differences in the average amount of protein, ash and moisture, but for fat no significant difference interaction between time and maintenance. In additional, by comparing of these factors by the Duncan test, in the dried samples greatest amount of protein (43/13%), fat (5/78%) and ash (23/25 %) were higher than those of in control samples, (protein: 12/36%, fat: 0/41%, ash: 5/82% and moisture: 75/67%) while control samples had higher moisture than dried samples. In all samples, control treatment had lowest fat (0/41%) and protein (12/36%), while dried samples had lowest moisture.

---

Umbilical cord (UC) is an important source of multipotential mesenchymal stem cells (MSCs). MSCs can be differentiated into different types of cells if they cultured under specific conditions. It has been proved that vitamin D3 can cause differentiation of stem cells in to osteoblast. Also, it has been observed that bee venom (BV) is effective in differentiation of cancerous cells. In this study differentiating potential of BV and vitamin D3 on MSCs to osteoblast was examined. Furthermore, our hypothesis was that BV could increase differentiating potential of vitamin D3. The cells obtained from UC tissues of 10-12 mouse embryos which were digested enzymatically and suspended in DMEM medium. For approving of stem cells, embryonic Oct4 marker was checked and the mesenchymal character of these cells was proven by surface markers including CD73, CD29, CD44. The flowcytometric analysis revealed high levels of these markers. After the second passage, in order to induce osteogenic differentiation, cells were cultured for 21days in DMEM medium containing different concentrations of BV, vitamin D3 separately and BV/vitamin D3 together. At first, cytotoxic effects of BV on MSCs were tested by MTT assay, which were shown that BV inhibited MSCs growth at higher concentrations than 6&mug/ml. Following the treatment, calcium’s level in the cells was determined by Alizarin red staining. Also, as an osteogenic marker, alkalin phosphatase level was measured in treated and non-treated cells. By Alizarin red staining and alkalin phosphatase assay, we found that BV With non-toxic concentrations (2µgr/ml, 4µgr/ml and 6µgr/ml) can cause a few osteogenic differentiation of MSCs. Whereas, usage of BV/vitamin D3 together, caused increasing the differential effects of vitamin D3. In conclusion we suggest that if MSCs were treated with bee venom and vitamin 3 at the same time, these components able to differentiate MSCs to osteoblast, therefore, they could be useful in cell therapy.

---

In the present study, the effects of indole acetic acid (IAA) on certain physiological and biochemical parameters in Glycine max (L.) Merr under aluminum chloride (AlCl₃)stress were studied. Seeds were sterilized and cultured in petri-dishes. Six days old seedlings were transferred to pots, and then they were irrigated with Hoagland solution in a growth chamber (with 16 h light period per 24 h, with day / night temperatures of 25/18 ºC respectively). Twenty days old plants were treated with different concentrations of AlCl₃ (0, 50, 100, 200 and 300 µM) and IAA (0, 50 and 100 µM). Plants were harvested 15 days after treatment. The plants exhibited decline in the relative water content (RWC), protein, soluble sugars, the chlorophylls a and b, carotenoids contents and photosynthetic rate with increase of aluminum chloride concentration, but the respiration rate and CO₂ compensation concentration were increased. With addition of IAA to culture solutions containing aluminum, the plants showed further decrease in the amount of soluble sugars, chlorophylls a and b, carotenoids and photosynthetic rate and further increase in other parameters. With increasing of aluminum concentration to culture solutions with and without IAA unsoluble sugars, proline and lipid peroxidation increased.
 

---

Nickelate with general formula La_2-xSr_xNiO₄ (x≈0.33) were synthesized by the sol–gel method. Then by changing the sintering temperature and growth parameters, particles with various sizes were produced. The crystal structure and physical properties of the prepared samples were investigated by X-ray diffraction (XRD), Fourier transform IR spectroscopy (FTIR), Energy dispersive X-ray spectroscopy (EDX) and field emission scanning electron microscopy (FE-SEM) and resistivity measurements from room temperature to low temperatures. The XRD results and investigation of the surface morphology show the lowest temperature to get a single phase tetragonal structure is 920°C. These data confirm the formation of single phase structure in samples sintered at higher temperatures. The particle size increases with increase in sintering temperature. The FE-SEM results show that the particles sizes are in range of 50nm to 2mm. The results of resistivity measurements versus temperature by fourprobe method indicate that the charge ordering transition temperature move to lower temperature with decrease in particle size.