Synthesis, in vitro urease inhibitory potential and molecular docking study of Benzimidazole analogues.

Despite of many diverse biological activities exhibited by benzimidazole scaffold, it is rarely explored for the urease inhibitory potential. For that purpose, benzimidazole analogues 1-19 were synthesized and screened for in vitro urease inhibitory potential. Structures of all synthetic analogues were deduced by different spectroscopic techniques. All analogues revealed inhibition potential with IC50 values of 0.90 ±â€¯0.01 to 35.20 ±â€¯1.10 µM, when compared with the standard thiourea (IC50 = 21.40 ±â€¯0.21 µM). Limited SAR suggested that the variations in the inhibitory potentials of the analogues are the result of different substitutions on phenyl ring. In order to rationalize the binding interactions of most active compounds with the active site of urease enzyme, molecular docking study was conducted.

Voltammetric determination of nitrite by using a multiwalled carbon nanotube paste electrode modified with chitosan-functionalized silver nanoparticles.

A cyclic voltammetric method is described for the determination of nitrite by using a multiwalled carbon nanotube paste electrode (MWCNT) that was modified with chitosan-functionalized silver nanoparticles (Chit-AgNPs). The AgNPs were prepared by one step procedure using chitosan as stabilizing agent. The resulting modified AgNPs were drop-coated onto the electrode. By combining the advantages of chitosan, AgNPs (in the form of Chit-AgNPs) and MWCNT, the assay exhibits a remarkable improvement in the cyclic voltammetric response towards the oxidation of nitrite at a typical peak potential of 0.81 V (vs. SCE) in buffer of pH 4.0. The accumulation of nitrite on the electrode also was achieved, and this further enhances the analytical sensitivity. Under optimized conditions, the oxidation peak current increases linearly in the 100 nM to 50 µM nitrite concentration range, and the detection limit is 30 nM. The method has high selectivity for nitrite even in the presence of other potentially interfering ions. Graphical abstract Schematic illustration of the prepared chitosan functionalized silver nanoparticles (transmission electron microscope image) and modification of multi-walled carbon nanotube paste electrode with chitosan functionalized silver nanoparticles for the electrochemical oxidation of nitrite to nitrate.

Synthesis, molecular docking study and in vitro thymidine phosphorylase inhibitory potential of oxadiazole derivatives.

We have synthesized oxadiazole derivatives (1-16), characterized by 1H NMR, 13C NMR and HREI-MS and screened for thymidine phosphorylase inhibitory potential. All derivatives display varied degree of thymidine phosphorylase inhibition in the range of 1.10 ±â€¯0.05 to 49.60 ±â€¯1.30 µM when compared with the standard inhibitor 7-Deazaxanthine having an IC50 value 38.68 ±â€¯1.12 µM. Structure activity relationships (SAR) has been established for all compounds to explore the role of substitution and nature of functional group attached to the phenyl ring which applies imperious effect on thymidine phosphorylase activity. Molecular docking study was performed to understand the binding interaction of the most active derivatives with enzyme active site.

Synthesis, SAR elucidations and molecular docking study of newly designed isatin based oxadiazole analogs as potent inhibitors of thymidine phosphorylase.

Thymidine phosphorylase is an enzyme involved in pyrimidine salvage pathway that is identical to platelet-derived endothelial cell growth factor (PD-ECGF) and gliostatin. It is enormously up regulated in a variety of solid tumors. Furthermore, surpassing of TP level protects tumor cells from apoptosis and helps cell survival. Thus TP is identified as a prime target for developing novel anticancer therapies. A new class of exceptionally potent isatin based oxadiazole (1-30) has been synthesized and evaluated for thymidine phosphorylase inhibitory potential. All analogs showed potent thymidine phosphorylase inhibition when compared with standard 7-Deazaxanthine, 7DX (IC50 = 38.68 ±â€¯1.12 µM). Molecular docking study was performed in order to determine the binding interaction of these newly synthesized compounds, which revealed that these synthesized compounds established stronger hydrogen bonding network with active site of residues as compare to the standard compound 7DX.

Synthesis, in vitro α-glucosidase inhibitory potential and molecular docking study of thiadiazole analogs.

α-Glucosidase is a catabolic enzyme that regulates the body's plasma glucose levels by providing energy sources to maintain healthy functioning. 2-Amino-thiadiazole (1-13) and 2-amino-thiadiazole based Schiff bases (14-22) were synthesized, characterized by 1H NMR and HREI-MS and screened for α-glucosidase inhibitory activity. All twenty-two (22) analogs exhibit varied degree of α-glucosidase inhibitory potential with IC50 values ranging between 2.30 ±â€¯0.1 to 38.30 ±â€¯0.7 µM, when compare with standard drug acarbose having IC50 value of 39.60 ±â€¯0.70 µM. Among the series eight derivatives 1, 2, 6, 7, 14, 17, 19 and 20 showed outstanding α-glucosidase inhibitory potential with IC50 values of 3.30 ±â€¯0.1, 5.80 ±â€¯0.2, 2.30 ±â€¯0.1, 2.70 ±â€¯0.1, 2.30 ±â€¯0.1, 5.50 ±â€¯0.1, 4.70 ±â€¯0.2, and 5.50 ±â€¯0.2 µM respectively, which is many fold better than the standard drug acarbose. The remaining analogs showed good to excellent α-glucosidase inhibition. Structure activity relationship has been established for all compounds. The binding interactions of these compounds were confirmed through molecular docking.

Synthesis and in vitro acetylcholinesterase and butyrylcholinesterase inhibitory potential of hydrazide based Schiff bases.

To discover multifunctional agents for the treatment of Alzheimer's disease, a series of hydrazide based Schiff bases were designed and synthesized based on multitarget-directed strategy. We have synthesized twenty-eight analogs of hydrazide based Schiff bases, characterized by various spectroscopic techniques and evaluated in vitro for acetylcholinesterase and butyrylcholinesterase inhibition. All compounds showed varied degree of acetylcholinesterase and butyrylcholinesterase inhibition when compared with standard Eserine. Among the series, compounds 10, 3 and 24 having IC50 values 4.12±0.01, 8.12±0.01 and 8.41±0.06µM respectively showed potent acetylcholinesterase inhibition when compared with Eserine (IC50=0.85±0.0001µM). Three compounds 13, 24 and 3 having IC50 values 6.51±0.01, 9.22±0.07 and 37.82±0.14µM respectively showed potent butyrylcholinesterase inhibition by comparing with eserine (IC50=0.04±0.0001µM). The remaining compounds also exhibited moderate to weak inhibitory potential. Structure activity relationship has been established. Through molecular docking studies the binding interaction was confirmed.

Removal of sulfur dioxide by carbon impregnated with triethylenediamine, using indigenously developed pilot scale setup.

In order to provide protection against extremely toxic gases, activated carbon (AC) adsorption has long been regarded to be a useful technology in terms of gas removal. AC without chemical impregnation has been considerably less effective than impregnated ACs. AC in present use was modified with an organic amine, i.e., triethylenediamine (TEDA) to enhance the physical and chemical properties of AC in order to remove specific poisonous gases. With the rising concern on environmental pollution, there has been an increased curiosity in ACs as the means for eliminating pollutants from environment. Purpose of this study was to assess the TEDA impregnated AC in terms of adsorption capability for simulant gas like SO2. Analysis was done in a properly designed setup. By using the scheme reported here, significant adsorption of toxic gas was obtained. Maximum removal capability observed by AC-4 for SO2 gas was 374 mg/g-C and its breakthrough time was 264 min. Breakthrough time and adsorption capacity of AC-4 was found to be 25 times and 10 times greater as compared to raw AC. Different characterization techniques were also used to study impregnated AC. It was found that chemical adsorption was the crucial means by which TEDA-impregnated AC removed the simulant gas. Langmuir model was best to represent equilibrium, and adsorption kinetics follow second-order model. The process was endothermic, favorable, and spontaneous.

Miscibility and thermal behavior of poly(methyl methacrylate) and polystyrene blend using benzene as a common solvent.

Polymer blending is one of the advanced technologies to attain polymeric material with tailored properties. In this work, the miscibility of Poly(methyl methacrylate) (PMMA) and Polystyrene (PS) blend in benzene was investigated by employing various techniques such as FTIR spectroscopy, viscosity measurement technique, light scattering techniques, DSC and TGA techniques over an extended range of concentrations, compositions, and temperatures. The results revealed that there exist hydrogen bonding and hydrodynamic interactions which led these polymers to get miscible to a large extent. The compatibility increased with the increasing PS contents or increase in temperature of the system. In addition, the thermal stability of blends was found to be improved with the increase in the compatibility of the polymer.

Investigation on Crystal-Structure, Thermal and Electrical Properties of PVDF Nanocomposites with Cobalt Oxide and Functionalized Multi-Wall-Carbon-Nanotubes.

Nanocomposites of polyvinylidene fluoride (PVDF) with dimensional (1D) cobalt oxide (Co3O4) and f-MWCNTs were prepared successfully by the solution casting method. The impact of 1D Co3O4 filler and 1D Co3O4/f-MWCNTs co-fillers on the structural, thermal, and electrical behavior of PVDF were studied. The crystal structural properties of pure PVDF and its nanocomposite films were studied by XRD, which revealed a significant enhancement of ß-phase PVDF in the resulting nanocomposite films. The increase in ß-phase was further revealed by the FTIR spectroscopic analysis of the samples. TG, DTA, and DSC analyses confirmed an increase in thermal stability of PVDF with the addition of nano-fillers as well as their increasing wt.%. From impedance spectroscopic studies, it was found that the DC conductivity of PVDF increases insignificantly initially (up to 0.1 wt.% of nano-fillers addition), but a significant improvement in DC conductivity was found at higher concentrations of the nano-fillers. Furthermore, it was observed that the DC conductivity decreases with frequency. The increase in DC conductivity corresponded to the strong interactions of nano-fillers with PVDF polymer chains.

Synthesis and Characterization of Ni Nanoparticles via the Microemulsion Technique and Its Applications for Energy Storage Devices.

Herein, a unique synthetic approach called microemulsion is used to create nickel nanoparticles (Ni-NPs). SEM, TEM, EDX, and XRD techniques were employed for the investigation of morphology and structures of the synthesized material. Electrons from electroactive components are transferred to external circuits by Ni-NPs' superior electrical conductivity and interconnected nanostructures, which also provide a large number of channels for ion diffusion and additional active sites. The experimental findings showed that as a positive electrode for supercapacitors (SC), Ni-NPs had an outstanding ability to store charge, with a dominant capacitive charge storage of 72.4% when measured at 10 mV/s. Furthermore, at 1 A/g, Ni-NP electrodes exhibit a maximum capacitance of 730 F/g. Further, the Ni-NP electrode retains 92.4% of its capacitance even for 5000 cycles, highlighting possible applications for it in the developing field of renewable energy. The current study provides a new method for producing high-rate next-generation electrodes for supercapacitors.

A comparative study of various grains from the different cities of Pakistan.

The fate of trace elements (like Ca, Fe, Al, Pb, K, and Cu) in various pulses (mash, mung, lentils and red kidney beans) of Pakistan has been studied. Samples were collected from two districts (Mansehra and Rawalpindi) and analyzed by wet acid digestion method using atomic absorption spectrophotometry. Experimental results show that the intensity of heavy metal accumulation in plants depends upon the type of the soil, the species of plants, the physicochemical properties of heavy metals, and their content in the soil. The obtained values were compared with the World Health Organization (WHO) standards for food quality. The grains from District Mansehra contained greater amount of trace metals as compared to those collected from District Rawalpindi. However, those values did not exceed the upper limits described by the WHO in nearly all the cases. Based on these findings, the consumption of pulses in larger amounts may easily be recommended.

Impregnation on activated carbon for removal of chemical warfare agents (CWAs) and radioactive content.

Nuclear, biological, and chemical warfare (NBC) agents cause an inevitable threat to defense forces and civilians. Exposure to these toxic agents causes a lot of damage to lives. One can avoid the damage of these toxic agents by taking appropriate preventive measures. Respiratory protection is obviously necessary when military personnel or civilians get bounded by such type of noxious situation as contaminant-free air is then required for breathing and it can only be provided by means of a proper gas mask and relevant canister. In purification of contaminated atmospheres, activated carbon has so far met with outstanding success. It removes toxic chemicals either by chemical or physical adsorption from the contaminated air. When any toxic chemicals get adsorbed on the modified impregnated carbon's surface, they usually adsorb there by means of chemical reactions. Destruction of adsorbed toxic substances is expected by such a reactive carbon. In this perspective, an attempt has been made to review the literature from past decades on the removal of toxic chemical warfare agents (CWAs) and radioactive content from air stream in case of any nuclear, biological, and chemical attack by selectively modifying or impregnating the activated carbon surface. This review also covers some important adsorption properties of materials being used in gas mask filters for effective removal of chemicals from airstream. The probable removal mechanisms of various chemical warfare agents and radioactive content have also been reviewed.

Synthesis, In vitro α-Glucosidase Inhibitory Potential and Molecular Docking Studies of 2-Amino-1,3,4-Oxadiazole Derivatives.

BACKGROUND: In the recent past, we have synthesized and reported different derivatives of oxadiazoles as potential α-glucosidase inhibitors, keeping in mind, the pharmacological aspects of oxadiazole moiety and in continuation of our ongoing research on the chemistry and bioactivity of new heterocyclic compounds. METHODS: 1,3,4-Oxadiazole derivatives (1-14) have been synthesized and characterized by different spectroscopic techniques such as 1H-, 13C-NMR and HREI-MS. RESULTS: The synthetic derivatives were screened for α-glucosidase inhibitory potential. All compounds exhibited good inhibitory activity with IC50 values ranging between 0.80 ± 0.1 to 45.1 ± 1.7 µM in comparison with the standard acarbose having IC50 value 38.45 ± 0.80 µM. CONCLUSION: Thirteen compounds 1-6 and 8-14 showed potential inhibitory activity as compared to the standard acarbose having IC50 value 38.45 ± 0.80 µM, however, only one compound 7 (IC50 = 45.1 ± 1.7 µM) was found to be less active. Compound 14 (IC50 = 0.80 ± 0.1 µM) showed promising inhibitory activity among all synthetic derivatives. Molecular docking studies were also conducted for the active compounds to understand the ligand-enzyme binding interactions.

Comparison of the effects of gamma or sonochemical irradiation of carbon nanotubes and the influence on the mechanical and dielectric properties of chitosan nanocomposites.

Chitosan-carbon nanotube (Chi-CNT) composite materials have been prepared with CNTs that were surface treated using either dilute acid combined with 20 kHz ultrasound or gamma-irradiation in air. The mechanical and dielectric properties have been measured and compared. Both modification methods gave nanocomposites with much improved tensile properties over native chitosan. The sonochemically treated samples were stronger with higher tensile strength but at the expense of lower elasticity and extensibility than found when γ-irradiation was used. Impedance spectra showed differences in the polymer chain transitions and in the conduction mechanisms within the nanocomposites. The results correlated well with previous work suggesting that the two modification techniques result in CNT surfaces with higher polarity. This enhances interfacial interactions with the chitosan matrix although the extent of functionalisation was greater in the sonochemical case. This work demonstrates that sonochemical modification under mild conditions is a useful method for modifying CNTs for inclusion in nanocomposite materials. However, the resulting material properties depend on the level of treatment so that the sonochemical conditions need to be carefully evaluated and controlled if the effects are to be optimised.

Sonochemical modification of carbon nanotubes for enhanced nanocomposite performance.

Multi-walled carbon nanotubes (CNTs) have been treated using 20kHz ultrasound in combination with dilute nitric and sulfuric acids at much lower concentrations than previously reported. The measurements revealed an optimum set of sonication conditions (in this case 30min at 12Wcm-2) exists to overcome aggregation of the nanotubes and to allow efficient dispersion in ethanol or in chitosan. Transmission electron microscopy and Raman spectroscopy suggested the removal of amorphous material and reduction of the CNT diameter as well as modifications to their defect structures. The surface oxidation was determined by FTIR spectroscopy. At longer times or higher ultrasound intensities, degradation such as nanotube shortening and additional defect generation in the graphitic network occurred and the benefits of using ultrasound decreased. The modified CNTs were used as fillers for chitosan films and gave a tenfold increase in tensile strength and integrity of the films. The methodology was combined with sonochemical generation of gold or iron oxide nanoparticles to produce a range of functional membranes for catalytic reductive hydrogenation or dye degradation under conditions that are more environmentally benign than those previously used. Our results further add to the usefulness of sonochemistry as a valuable tool in preparative materials chemistry but also illustrate the crucial importance of careful control over the experimental conditions if optimum results are to be obtained.

Chitosan/CNTs green nanocomposite membrane: synthesis, swelling and polyaromatic hydrocarbons removal.

Carbon nanotubes (CNTs) were irradiated in air at 100 kGy under gamma radiations. The Raman spectroscopy of γ-treated CNTs showed distinctive changes in the absorption bands. The CNTs were mixed with blend of chitosan (Cs)/poly (vinyl alcohol) (PVA) and crosslinked with silane. The chemical reactions between the components affected the position and intensities of the infrared bands. Scanning electron micrograph of Cs/CNTs nanocomposite membrane showed the homogeneous dispersion of CNTs in the polymer matrix. The addition of CNTs lowered its swelling in water. Naphthalene (NAPH) was selected as a model compound and its removal was studied using HPLC technique. This membrane showed fast uptake of NAPH and 87% was removed from water within 30 min. The NAPH loaded membrane showed strong chemical interactions and cannot be desorbed. The fast uptake of PAHs and the green nature of this membrane made them suitable candidates for clean-up purposes.