Lyubeznik numbers of monomial ideals

We study Bass numbers of local cohomology modules supported on squarefree monomial ideals paying special attention to Lyubeznik numbers. We build a dictionary between local cohomology modules and minimal free resolutions that allow us to interpret Lyubeznik numbers as the obstruction to the acyclicity of the linear strands of the Alexander dual ideals. The methods we develop also help us to give a bound for the injective dimension of the local cohomology modules in terms of the dimension of the small support.Comment: 28 page

Artinian and non-artinian local cohomology modules

Let $M$ be a finite module over a commutative noetherian ring $R$. For ideals \fa and \fb of $R$, the relations between cohomological dimensions of $M$ with respect to \fa, \fb, \fa\cap\fb and \fa+ \fb are studied. When $R$ is local, it is shown that $M$ is generalized Cohen-Macaulay if there exists an ideal \fa such that all local cohomology modules of $M$ with respect to \fa have finite lengths. Also, when $r$ is an integer such that $0\leq r< \dim_R(M)$, any maximal element \fq of the non-empty set of ideals \{\fa : \H_\fa^i(M) is not artinian for some $i$, $i\geq r$$\}$ is a prime ideal and that all Bass numbers of \H_\fq^i(M) are finite for all $i\geq r$.Comment: 10 pages, to appear in Canadian Mathematical Bulleti

C-fpn- Injective and C-fpn- Flat modules under Foxby equivalence

Let S and R be rings, SCR a (faithfully) semidualizing bi-module, and n 1 a natural number. In this paper, we introduce the concepts of C-fpn-injective and C-fpn-at modules. Then we investigate the classes of this modules, namely CfpnI(R) and CfpnF(S). Over any arbitrary ring, we study the existence of CfpnI(R) and CfpnF(S) covers and preenvelopes. Also, we investigate Foxby equivalence relative to C-fpn-injective and C-fpn-at modules. Finally, we give some applications over commutative rings

A hybrid functions method for solving linear and non-linear systems of ordinary differential equations

In the present paper, we use a hybrid method to solve linear or non-linear systems of ordinary differential equations (ODEs). By using this method, these systems are reduced to a linear or non-linear system of algebraic equations. In error discussion of the suggested method, an upper bound of the error is obtained. Also, to survey the accuracy and the efficiency of the present method, some examples are solved and comparisons between the obtained results with those of several other methods are carried out

CARBON DIOXIDE MINIMUM MISCIBILITY PRESSURE ESTIMATION (CASE STUDY)

Carbon dioxide flooding is considered to be one of the most effective enhanced oil recovery methods for the light oil reservoirs. Depending on the operating pressure, the process might be miscible or immiscible. Minimum miscibility pressure (MMP) is the most important parameter for assessing the applicability of any miscible gas flood for an oil reservoir. The miscibility condition is determined by conducting displacement tests at various pressures and the recovery is expected to improve as the displacement pressure increases, and then stays almost constant above the MMP. In this study, the MMP of pure carbon dioxide and an Iranian oil reservoir is estimated using slim-tube test. The experiment is performed under constant CO2 injection rate anddifferent displacement pressures above the bubble point pressure; input and output pressures are continually monitored during the test; the effluent liquid is flashed to atmospheric conditions and produced gases are passed through gas chromatography for compositional analysis. Volumetric oil recovery is measured, and oil recovery is plotted against the injection pressure at a 1.2 pore volume of the injected fluid. The results show that the oil recovery is more than 90% of original oil in place for all the pressures with a constant slope above the bubble point pressure. Therefore, MMP is considered to be equal to the bubble point pressure. In addition to the plot of oil recovery versus pressure, miscibility is also confirmed by the effluent gas composition, slim-tube pressure drop, and visual observations of phase behavior. The single phase high pressure fluid at the outlet of slim-tube, the small pressure drop across it, and no methane bank in the composition of effluent gas indicate that the miscibility is completely achieved. The experimental results are validated by modeling the test using a fully compositional simulator. The effect of varying CO2 mole fraction in the injected fluid is also investigated. The results show that an increase in CO2 mole fraction of the injected gas significantly decreases MMP. </span

Effect of Sumac (Rhus coriaria) Extract on Blood Lipid Profile in White Wistar Rat

Background: Hyperlipidemia is one of the chronic diseases whose current solutions are the proper diet and chemical drugs. Evaluation of accessible medicinal plant recourses has an important role to prevent and treat the hyperlipidemia. The present study aimed to investigate the effect of sumac (Rhus coriaria) extract on blood lipid profile in white Wistar rat.Methods: This laboratory animal experiment was conducted on 21 white Wistar rats during four weeks. The research units divided into three groups separately were fed by normal diet, fatty diet without sumac extract and fatty diet with sumac extract. The samples were excluded after appearing sick-like behaviors. Finally, data were analyzed in SPSS ver. 16 software using ANOVA and LSD tests.Results: The mean weight of rats was 310±26 gram. The mean blood cholesterol had significant difference in fatty diet with sumac group in compared with control group from the second week to the end of study (P&lt;0.001), also the mean triglyceride was increased significantly during the study in fatty diet with sumac extract group (P=0.47). The mean HDL and LDL had no significant change during the study (P&gt;0.05).Conclusion: According to the findings of this study, the use of sumac with fatty diet can be effective to reduce blood cholesterol in prevention and treatment of hyperlipidemia

Penicillium chrysogenum-Derived Silver Nanoparticles: Explorationof Their Antibacterial and Biofilm Inhibitory Activity Againstthe Standard and Pathogenic Acinetobacter baumannii Compared to Tetracycline

Abstract: This study was aimed to evaluate the antibacterial and biofilm inhibitory activity of Penicillium chrysogenum-derivedsilver nanoparticles (AgNPs) against the standard and pathogenic Acinetobacter baumannii using a 96-well microtiterplate-based method. The AgNPs were characterized by using UV–Vis, TEM, AFM, XRD, DLS, Zeta potential, and FT-IR.The nanoparticles (NPs) were fabricated with a spherical shape and an average hydrodynamic diameter of 48.2 nm. Theminimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of AgNPs were found to be 4and 32 lg/mL respectively, whereas the MIC and MBC of tetracycline were found to be 1024 and 8192 lg/mL against A.baumannii (ATCC 19606). The AgNPs and tetracycline represented considerable biofilm inhibitory activity against boththe standard and pathogenic A. baumannii at the studied concentrations. However, the AgNPs depicted higher potency toinhibit the process of biofilm formation of some pathogenic A. baumannii species compared to tetracycline. The AgNPs atthe concentration of 0.5*MIC (2 lg/mL) inhibited above 90% biofilm inhibition, whereas tetracycline reached 90% biofilminhibition at the concentration of 4*MIC (4096 lg/mL) against A. baumannii (ATCC 19606). However, further studies arerequired to evaluate the biofilm inhibitory efficacy of biogenic AgNPs in vivo. Keywords: Silver nanoparticles, Biosynthesis, Antibacterial activity, Biofilm inhibitory activit