Sharif Digital Repository

Excimer laser at 193 nm was irradiated on the renal tissues during various exposure times in order to investigate the chemical and physical surface properties using Fourier transform infrared spectroscopy, photo electron spectroscopy, contact angle measurements, and tensile test accordingly. We have shown that ultraviolet laser strongly alters the oxygen content of skin layer that causes changes in the tissue morphology leading to significant skin hydrophilicity  

Lander-Waterman's coverage bound establishes the total number of reads required to cover the whole genome of size G bases. In fact, their bound is a direct consequence of the well-known solution to the coupon collector's problem which proves that for such genome, the total number of bases to be sequenced should be O(G ln G). Although the result leads to a tight bound, it is based on a tacit assumption that the set of reads are first collected through a sequencing process and then are processed through a computation process, i.e., there are two different machines: one for sequencing and one for processing. In this paper, we present a significant improvement compared to Lander-Waterman's... 

The unsymmetrical tetradentate Schiff base H2L was prepared by the reaction of salicylaldehyde with the mono Schiff base derived from o-phenylenediamine and o-hydroxyacetophenone (HL1). NiL and CuL complexes were prepared and characterized by 1H NMR, IR and single crystal X-ray structure determination. Crystal data for NiL: triclinic space group P-1, a = 7.190 (2) Å, b = 13.059 (4) Å, c = 17.867 (10) Å, α = 74.888 (10)°, β = 84.206 (10)°, γ = 86.542 (2)° and z = 4. Crystal data for CuL: monoclinic space group P2I/n, a = 12.8209 (6) Å, b = 6.988 (3) Å, c = 18.601 (9) Å, β = 105.15° and z = 4. The Ni and Cu atoms have a slightly distorted square-planar coordination geometry  

A highly efficient and simple synthesis of dithiocarbamates is possible based on the one-pot reaction of amines, CS2, and alkyl halides without using a catalyst under solvent-free conditions. The mild reaction conditions, high yields, and broad scope of the reaction illustrate the good synthetic utility of this method. The reaction is a highly atom-economic process for production of S-alkyl thiocarbamates and successfully can be used in high quantities in the pharmaceutical or agrochemical industries  

The ABC index is a topological index was defined as where dG(u) denotes degree of vertex u. Now we define a new version of ABC index as where The goal of this paper is further the study of the ABC4 index  

Let G be a graph. The first and second Zagreb index of G is defined as M1(G)= Σ degG(V)2 and M2(G)= Σ degG(u)degG(V) respectively. In this paper we compute Zagreb indices of chain graphs  

We provide a characterization of energy in the form of exchanged heat and work between two interacting constituents of a closed, bipartite, correlated quantum system. By defining a binding energy we derive a consistent quantum formulation of the first law of thermodynamics, in which the role of correlations becomes evident, and this formulation reduces to the standard classical picture in relevant systems. We next discuss the emergence of the second law of thermodynamics under certain-but fairly general-conditions such as the Markovian assumption. We illustrate the role of correlations and interactions in thermodynamics through two examples  

Hydroxyapatite is the most important bio ceramic, due to its structure and chemical composition which is similar to bone. Since feeble fracture toughness, brittleness and low tensile strength have restricted their use, for overcoming this problem, they were often used as a secondary component. HAp-Al2O3 nano-composite powder combined the benefits of biocompatibility of HAp and high strength of Al2O3. When HAp-Al2O3 nano-composite powders were sintered at a higher temperature than 1100- 1200°C, HAp was decomposed and converted to the second phase of TCP, due to the formation of calcium aluminate increasing decomposition speed of HAp to TCP at higher degree than 1100-1200°C temperatures;... 

We have investigated different algorithms for the simulation of kinetics of small systems. We have simulated the first order reversible reaction with the Gillespie, Gibson and Brack time simulation as a function of Poisson distribution and compared the results of three algorithms. We have also simulated intracellular viral kinetics for a genome with Gillespie and Poisson distribution algorithms  

Herein we describe the synthesis and characterization of the first platinum(IV) metal-organic cage [(Me3PtIV)8(byp)12](OTf)8 (2), in which the organometallic moieties trimethylplatinum(IV) (PtMe3) occupied the corners of a cubane structure and 4,4′-bipyridine ligands used as linkers. The first-principles density functional theory calculations showed that the highest occupied molecular orbitals were localized on the PtMe3 moieties, while the lowest unoccupied molecular orbitals were distributed on the organic linkers. © 2021 American Chemical Society  

From scaling arguments and numerical simulations, we investigate the properties of the generalized elastic model (GEM) that is used to describe various physical systems such as polymers, membranes, single-file systems, or rough interfaces. We compare analytical and numerical results for the subdiffusion exponent β characterizing the growth of the mean squared displacement 〈 (δh)(2)〉 of the field h described by the GEM dynamic equation. We study the scaling properties of the qth order moments 〈 {divides}δh{divides}(q)〉 with time, finding that the interface fluctuations show no intermittent behavior. We also investigate the ergodic properties of the process h in terms of the ergodicity... 

Hartree-Fock and density functional theory methods at gauge invariant atomic orbital approach with different simplest basis sets were employed for the computation of chemical shifts. The wave functions for calculating gas-phase 1H and 13C chemical shifts have been optimally selected using empirical models. The effects of electron correlation treatment, triple-ξ valance shell, diffuse function, and polarization function on calculated chemical shifts have been discussed. Through empirical scaling of shielding, accurate predictions of 1H chemical shifts are achieved for the molecules studied, when considering small Pople basis sets. Gas phase experimental 1H chemical shifts in alcohols, amines... 

A highly efficient and simple synthesis of unsymmetrical thioureas is reported based on the reaction of readily synthesized dithiocarbamates with amines, without using any catalyst under solvent-free conditions. The short reaction time, high yields, and solvent-free conditions are advantages of this method. We did not observe the formation of any symmetric disubstituted thiourea, under these reaction conditions. © 2008 Elsevier Ltd. All rights reserved  

A dense membrane of La0.6Sr0.4Co0.8Fe0.2O3- δ (LSCF) perovskite was prepared by a new chelating agent, ethylene diamine N,N,N′,N′-tetra N-acetyl diamine (EDTNAD). As a potent ligand, EDTNAD provided a facile one-step method to form complexes of the four metal ions, simultaneously. The oxygen permeation flux through the pure perovskite LSCF dense membrane was measured over temperature range of 1073-1223 K, thickness of 0.7-1.0 mm and oxygen partial pressure of 0.1-1.0 bar. Oxidative coupling of methane (OCM) reaction using LSCF disk in the atmospheric membrane reactor and over the temperature range of 1073-1173 K showed a C2 selectivity of 100% and C2 yield of 5.01% at 1153 K. Furthermore,... 

An efficient and highly chemoselective synthesis of symmetrical secondary amines via reductive amination of aldehydes with inexpensive and commercially available HMDS and sodium borohydride in high to quantitative yields is reported. © 2008 Elsevier Ltd. All rights reserved  

An environmentally benign, highly efficient, and simple protocol for the synthesis of various structurally divergent dithiocarbamate derivatives in one-pot reaction of amines, carbon disulfide, and epoxides, without using any solvent and catalyst at room temperature, is presented. This new procedure has the advantages of higher yield, lower cost, reduced environmental impact, and simple work-up procedure. © Georg Thieme Verlag Stuttgart  

In this work, for the first time, we presented a novel design strategy to fabricate a new type of Octa-aminopropyl polyhedral oligomeric silsesquioxane hydrochloride salt (OA-POSS)-based Alg/PAAm DN gels, consisting of PAAm gel as the first chemical network and Alg/OA-POSS gel as the second chemical-physical network. Incorporation of OA-POSS nanoparticles with various feed ratio into the second network not only led to form strong coordination interactions but also in comparison to the other Alg/PAAm gels demonstrated superior mechanical properties. pH, temperature, contact time and salt effects parameters were studied on the swelling and dye removal properties of the synthesized DN hybrid... 

In this study, the performance of the electrical method in MDF wastes recycling was determined. For investigating the practical aspect of the electrical method, the hydrothermal method as a known recycling method was studied too. The recycling process by electrical method conducted for two different time durations (2 and 4 min) at a temperature of 100 °C and recycling using the hydrothermal method was done at a temperature of 105 °C for 150 min under 4 bar pressure with subsequent refining step. Recycled fibers were analyzed by determination of the chemical composition of fibers and fiber classification. After that, laboratory MDF boards with dimensions of 35 × 35 × 12 mm3 and density of... 

In this paper, a new approach is presented for optimal control of large-scale chemical processes. In this approach, the chemical process is decomposed into smaller sub-systems at the first level, and a coordinator at the second level, for which a two-level hierarchical control strategy is designed. For this purpose, each sub-system in the first level can be solved separately, by using any conventional optimization algorithm. In the second level, the solutions obtained from the first level are coordinated using a new gradient-type strategy, which is updated by the error of the coordination vector. The proposed algorithm is used to solve the optimal control problem of a complex nonlinear...