Prediction of relative solvent accessibility by support vector regression and best-first method

Since, it is believed that the native structure of most proteins is defined by their sequences, utilizing data mining methods to extract hidden knowledge from protein sequences, are unavoidable. A major difficulty in mining bioinformatics data is due to the size of the datasets which contain frequently large numbers of variables. In this study, a two-step procedure for prediction of relative solvent accessibility of proteins is presented. In a first “feature selection” step, a small subset of evolutionary information is identified on the basis of selected physicochemical properties. In the second step, support vector regression is used to real value prediction of protein solvent accessibility with these custom selected features of evolutionary information. The experiment results show that the proposed method is an improvement in average prediction accuracy and training time

Fast and green synthesis of biologically important quinoxalines with high yields in water

Optimal method were developed for the green synthesis of quinoxaline derivatives based on the highly efficient and simple condensation reaction of various aromatic 1,2-diketones and 1,2-diamines in nearly quantitative yields in water. In this method we did not use any catalyst. The very mild reaction conditions, the high yields of the products, and the absence of any catalyst make this methodology an efficient and green route for synthesis of quinoxalines

Transition metal-free oxidation of benzylic alcohols to carbonyl compounds by hydrogen peroxide in the presence of acidic silica gel

Oxidation of alcohols to carbonyl compounds has become an important issue in the process industry as well as many other applications. In this method, various benzylic alcohols were successfully converted to corresponding aldehydes and ketones under transition metal-free condition using hydrogen peroxide in the presence of some amount of catalytic acidic silica gel. Silica gel is inexpensive and available. One of the most important features of this method is its short reaction time

Preparation of novel Zn–Al layered double hydroxide composite as adsorbent for removal of organophosphorus insecticides from water

Abstract In this work, a new and efficient composite LDH with high adsorption power using layered double hydroxide (LDH), 2,4-toluene diisocyanate (TDI), and tris (hydroxymethyl) aminomethane (THAM) was designed and prepared, which was used as an adsorbent to adsorb diazinon from contaminated water. The chemical composition and morphology of the adsorbent were evaluated using Fourier transform infrared (FTIR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), Energy dispersive X-ray (EDX) and Field emission scanning electron microscopy (FESEM) techniques. Also, the optimal conditions for adsorption of diazinon from water were determined by LDH@TDI@THAM composite. Various parameters like the effect of adsorbent dosage, pH, concentration and contact time of diazinon were studied to determine the optimal adsorption conditions. Then, different isotherm models and kinetic adsorption were used to describe the equilibrium data and kinetic. Also, the maximum adsorption capacity is obtained when the pH of the solution is 7. The maximum adsorption capacity for LDH@TDI@THAM composite was 1000 mg/g at 65 °C and the negative values of ΔG indicate that the adsorption process is spontaneous. After that, studying the reusability of LDH@TDI@THAM composite showed that the removal of diazinon by LDH@TDI@THAM was possible for up to four periods without a significant decrease in performance

g-C₃N₄/Ni Nanocomposite: An Efficient and Eco-Friendly Recyclable Catalyst for the Synthesis of Quinoxalines

Presently, with increasing environmental concerns, the development of sustainable and friendly heterogeneous catalysts has attracted more and more attention, in both the scientific and industrial communities. Hence, the use of nanocatalysts with well-defined structures, that are environmentally benign, with high catalytic activity, and high chemical stability are desirable, instead of corrosive and hazardous chemicals. In recent years, polymeric mesoporous graphitic carbon nitride (g-C3N4) has turned out to be a fascinating choice for catalyst or catalyst support due to its special physical and chemical properties, thermal stability, non-toxicity, unique electronic properties, and large surface area. The incorporation of nitrogen atoms in the carbon architecture of the g-C3N4 gives rise to the active chemical sites exposed on the surface. On the other hand, depositing metal nanoparticles onto g-C3N4 is an effective strategy to enhance the catalytic activity of g-C3N4. In the present study, g-C3N4/Ni as a recyclable and highly efficient heterogeneous catalyst, with a good porous structure, has been prepared and its catalytic activity was investigated for the synthesis of quinoxaline derivatives

Improved Visible-Light Photocatalytic Activity of g-C3N4/CuWO4 Nanocomposite for Degradation of Methylene Blue

In recent years, heterogeneous semiconductor photocatalysts have attracted great attention in the arena of environmental remediation and solar energy conversion; because, sunlight energy is a renewable, cheap, and accessible source of energy and also converting solar energy to chemical energy can be declined the energy crisis and global warming. Development of visible light heterogeneous photocatalysts with high efficiency and chemical stability is important for catalysis researchers. Among different types of semiconductor material, polymeric graphitic carbon nitride (g-C3N4) with a medium band gap of about 2.7 eV has been widely applied in photodegradation of organic pollutants, water splitting, CO2 reduction, solar cells, energy storage, and organic synthesis. Unfortunately, due to the high rate recombination of photoinduced carriers, the photocatalytic performance of the bare g-C3N4 is still poor. Hence, many strategies including metal doping, noble metal deposition, and coupling with semiconductor composites have been employed to modify g-C3N4. Herein, we report the synthesis of g-C3N4/CuWO4 nanocomposite via a hydrothermal process. The prepared visible-light-driven nanocomposite exhibited an enhanced photocatalytic activity compared with bare g-C3N4 for the degradation of methylene blue (MB) under LED light irradiation

1,4-Butane-Sultone Functionalized Graphitic Carbon Nitride as a Highly Efficient Heterogeneous Catalyst for the Synthesis of 2,3-Dihydroquinazolines Derivatives

1,4-Butane-sultone functionalized graphitic carbon nitride nanosheets (g-C3N4@Bu-SO3H) was prepared and applied as an efficient heterogeneous catalyst for the synthesis of various quinazolines derivatives with high yield. In next step, the structure and morphology of catalyst was characterized by different analyses such as, FT-IR, EDS, XRD and FE-SEM. On the other side, considering the noticeable features of g-C3N4@Bu- SO3H such as high stability, easy to synthesize, non-toxicity, excellent reusability, and so on, the synthesis of 2,3-dihydroquinazolines derivatives with numerous advantages such as short reaction time reaction condition, easy separation and etc were realized

Water-Soluble Phosphated Graphene: Preparation, Characterization, Catalytic Reactivity, and Adsorption Property

An efficient method for the preparation of water-soluble phosphated graphene for the first time is developed. Graphene oxide (GO) was synthesized through a modified Hummers’ method and functionalized by phosphate groups with phosphorus trichloride and triethylamine in tetrahydrofuran (THF). The morphology and chemical structure of phosphorylated graphene oxide (PGO) and heat-treated PGO (PGO-400) were characterized by X-ray diffraction, Fourier transform infrared spectrometry, scanning electron microscopy, analytical X-ray spectroscopy, atomic force microscopy, diffuse-reflectance spectrometry, thermogravimetric analyses, differential thermogravimetric analysis, Brunauer–Emmett–Teller and Barrett–Joyner–Halenda methods, Raman spectroscopy, and X-ray photoelectron spectroscopy. The acidity of PGO and PGO-400 was measured by a back-titration method. PGO-400 offers extraordinary electronic and thermal properties, cation-exchange capacity, and water dispersibility. The combination of cation-exchange capacity and water dispersibility of PGO-400 offers a variety of applications in organic synthesis and adsorbent sciences