Journal of Sciences, Islamic Republic of Iran
Year:2009 | Volume:20 | Issue:1|Papers Count:11

Hereditary nonpolyposis colorectal cancer is the most common form of hereditary colorectal cancers accounting for 5 to 10% of all colon carcinoma. It is inherited in an autosomal dominant mode and caused by hereditary mutations in mismatch repair genes (MMR) chiefly MLH1 and MSH2. The lifetime risk of colon cancer in affected persons is 80%. Screening, prevention strategies and consequently treatment options will be improved by understanding of the genetic basis of this disorder. The aim of this study was to assess mutations in MLH1 and MSH2 genes in a subset of Iranian HNPCC patients. The families that fulfill Amsterdam criteria were selected as HNPCC families. Genomic DNA was extracted from the peripheral blood of the samples and mutations of MLH1 and MSH2 were detected by PCR-single strand conformation polymorphism (PCR-SSCP) and DNA sequencing techniques. Hereditary mutations were found in 20 cases. Of these mutations, 14 were found in MLH1 and 6 in MSH2 genes thus MLH1 gene had higher mutation rate than MSH2. Eighteen out of 20 detected mutations in our population were previously reported and two were novel. Our results demonstrated that mutation range as well as genes involved in HNPCC is different from one region to other and characterizing mutations could be very helpful in diagnosis of the at risk individuals.

Homeobox genes encode transcription factors which play important roles in the developmental processes of many multicellular organisms. TGIFLX/Y (TGIFLX and TGIFLY) are members of the homeobox superfamily of genes. Their expressions are specifically detected in the human adult testis but their functions are remained to be investigated. In this investigation we cloned full length of TGIFLY cDNA and produced recombinant GST-TGIFLY protein in bacterial system. Here we present production of GST-TGIFLY fusion protein as a soluble protein. The recombinant protein was confirmed by western blot analysis using anti-GST antibody. Through a single purification procedure using MagneGST Beads, approximately 20 mg of the recombinant protein was obtained per liter of bacterial culture. We suggest that GST-TGIFLY fusion protein could be utilized as a valuable molecular tool on investigation of TGIFLY target genes and identification of co-factors or partner proteins involved in TGIFLY function in normal and abnormal development.

The nanoparticles of Ni–Si mixed oxides were prepared by co-precipitation method using nickel nitrate; Ni(NO3)2 6H2O and tetraethylorthosilicate (TEOS).The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and hydrogen temperature program reduction (H2- TPR). The results revealed that Ni–Si mixed oxides particles were obtained with average particle size 1-2 nm. The Ni-Si nanoparticles mixed oxides successfully catalyzed the partial oxidation of methane (POM) to hydrogen and carbon monoxide (Syn gas) using a fixed-bed reactor with about 92% activity and high selectivity. No coke formation and deactivation of catalyst were observed during the course of reaction. Particularly significant is the similar reactivity of this catalyst with that of Ni-Ce-Zr mixed oxides.

The study of planktonic foraminifera in Jorband section reveals two major events in Campanian- Maastrichtian boundary and early-late Maastrichtian biodiversification.In this study, occurrence and species richness of planktonic foraminifera in Jorband area show the warm marine environment dominant during early to late Campanian and it could be correlating by tropical and subtropical biozones. The warm condition converted to rapid cooling exactly in Campanian- Maastrichtian boundary. This rapid changing in temperature was not important effecting in extinction species but make important differences in number of species. Increasing the heterohelicids populations associated with surface dwellers and decreasing of globigerinids show the rapid regression in Jorband area in the Campanian-Maastrichtian boundary. The cooler condition is dominated during early Maastrichtian, whereas heterohelicids were associated by rugoglobigerinids and globigerinelloids. In the late Maastrichtian, abundances of double-keeled species show high sea level and warmer condition dominated in Jorband area in Planoglobulina brazoensis zone (CF5) and Racemiguembelina fructicosa zone (CF4).

The source of cement in oilfields is critical to the prediction of the distribution of cements in the reservoirs and also prediction of reservoir quality. The source of mineral forming cements has been determined for the Storrington oolitic carbonate reservoir (Middle Jurassic Great Oolite Formation, Weald Basin, onshore UK) using a combination of petrography, electron microscopy, fluid inclusion analysis, atomic absorption spectrometry and stable isotopes analysis techniques. Petrographic interpretations revealed that ferroan calcite cement is the most significant diagenetic mineral and has a major control on reservoir quality. The preferred conclusion from this study is that the Great Oolite reservoir has acted as closed system during early diagenesis and has performed as open system during burial diagenesis. Also, elements for burial diagenetic cements have been sourced from neighbouring formation. Finally, stable isotopes analysis demonstrated that the dominant source of carbon in the Great Oolite reservoir is marine and is derived from the rock itself.

Nonlinear difference equations of higher order are important in applications; such equations appear naturally as discrete analogues of differential and delay differential equations which model various diverse phenomena in biology, ecology, economics, physics and engineering. The study of dynamical properties of such equations is of great importance in many areas. The autonomous difference equations have been studied extensively. The situation is more complicated when the considered model is nonautonomous. In this work we study global attractivity and boundedness of solutions of the following nonautonomous difference equation of order k +1, x n+1=anxn/1+xn+…+xn-k in which {an} a is a positive bounded sequence. This equation is nonautonomous form of the logistic type difference equation with several delays. We prove that if liminf an n n®¥ >1 every positive solution is bounded and persistence. Furthermore we prove that when we have a positive solution {`xn} such that  k (k+1) limsup xn £1, + ≤ , then for all positive solutions { xn }, lim n®¥  xn/ `xn =1.

In this paper, we generalize a theorem of Shao [12] by assuming that {Xn} is a sequence of linear negatively dependent random variables. Also, we extend some theorems of Chao [6] and Thrum [14]. It is shown by an elementary method that for linear negatively dependent identically random variables with finite p –th absolute moment (p³2) p the weighted sums 1/An åni=1 aniXi converge to zero as where An=n1/p and (åni=1 a2ni) {an,i} a is an array of real numbers. Moreover, we prove the almost sure convergence for weighted sums åni=1 aniX, n³1, when {Xi, i ³ 1} i is a sequence of pairwise negative quadrant dependence stochastically bounded random variables under some suitable conditions on an,i.

Consider search designs for searching one nonzero 2- or 3-factor interaction under the search linear model. In the noisy case, search probability is given by Shirakura et al. (Ann. Statist. 24(6) (1996) 2560). In this paper some new properties of the searching probability are presented. New properties of the search probability enable us to compare designs, which depend on an unknown parameter ρ, for all values of the parameter without needing to check for different values of ρ. Two new quantitative interval scale and parameter free criteria based on search probabilities are proposed for design comparison. These criteria are used to compare given designs. The equivalent search designs is defined based on new proposed criteria and present a class of equivalent designs which are orthogonal arrays of strength 2.

We study entanglement and squeezing of a cluster of spin systems under the influence of the two-axis counter twisting Hamiltonian. The squeezing parameters given by Wieland et al and also by Kitagawa et al. are chosen as the criteria of spin squeezing. The criterion of pair wise entanglement is chosen to be the concurrence and that of the bipartite entanglement the linear entropy. We also define a new squeezing parameter h, which plays a direct role in the investigation of the relationship between squeezing and entanglement. We observe that if the system is squeezed according to the Wineland’s criterion, it is squeezed according to the Kitagawa’s also, but the reverse is not always true. Moreover, if the system is squeezed according to Kitagawa’s criterion, it is pairwise entangled simultaneously and vice versa. It is also observed that the entropy is a linear function of the parameter h2.