Synthesis of isoniazid-1,2,3-triazole conjugates: Antitubercular,antimicrobial evaluation and molecular docking study

In the present study, a series of new isoniazid-1,2,3-triazole conjugates ( 5a-k ) was synthesized via click chemistry approach. The newly synthesized compounds were assessed for their in vitro antitubercular and antimicrobial activities. The compound 5g has displayed potent antitubercular activity against Mycobacterium tuberculosis H37Rv (Mtb) with MIC value 1.56 μg/mL. The active compounds were screened for their cytotoxicity profile by MTT assay against RAW 264.7 cell line. The four compounds have shown good in vitro antimicrobial activities against both antibacterial and antifungal pathogens. A molecular docking study was accomplished to identify the probable mode of action of synthesized derivatives. These compounds have shown excellent binding affinity toward Enoyl-acp reductase (INHA) and DNA gyrase.     

Density functional theory study of ω phase in steel with varied alloying elements

The presence of a long-abandoned hexagonal omega (ω) phase in steel samples is recently gaining momentum owing to the advances in transmission electron microscopy (TEM) measurements, even though it is already reported in other transition-metal alloys. The stabilization of this metastable phase is mainly investigated in presence of C, even though the formation of the ω phase is attributed to the combined effect of many factors, one among which is the enrichment of solute elements such as Al, Mn, Si, C, and Cr in the nanometer-sized regimes. The present study investigates the effect of the above alloying elements in ω-Fe using density functional theory (DFT) calculations. It is seen that the magnetic states of the atoms play a major role in the stability of ω-Fe. Cohesive energy calculations show that the alloying elements affect the energetics and stabilization of ω-Fe. Further, density of states calculations reveal the variation in d-band occupancy in the presence of alloying elements, which in turn affects the cohesive energy. Phonon band structure calculations show that only ω-Fe with substitutional C shows positive frequencies and hence possess thermodynamic stability. Finally, we confirm the existence of ω-Fe using TEM measurements of a steel sample containing the same alloying elements. Our results can shed light on the stabilization of the ω in other transition-metal alloys as well, in the presence of minor alloying elements.     

Mechanism of nitrite reduction at T2Cu centers: electronic structure calculations of catalysis by copper nitrite reductase and by synthetic model compounds

The mechanism of nitrite reduction at the Cu(II) center of both copper nitrite reductase and a number of corresponding synthetic models has been investigated by using both QM/MM and cluster calculations employing density functional theory methods. The mechanism in both cases is found to be very similar. Initially nitrite is bound in a bidentate fashion to the Cu(II) center via the two oxygen atoms. Upon reduction of the copper center, the two possible coordination modes of the protonated nitrite, by either nitrogen or a single oxygen atom, are close in energy, with nitrogen coordination probably preferred. Further protonation of this species leads to N-O bond cleavage, and an electron transfer from the Cu(I) center to the N-O+ ligand, resulting in loss of NO and regeneration of the resting state of the enzyme having a bound water molecule.     

Scavenging of Priority Organic Pollutants from Aqueous Waste Using Granular Activated Carbon

Compliances with stringent effluent discharge limits imposed by environmental protection agencies (EPA) and the most economic way of achieving it without loss of production has led to continued refinement, recognition and development of promising wastewater treatment technologies. Many organic compounds present in industrial and domestic wastewaters are carcinogenic in nature. Removal of these organic compounds from wastewater has become a great challenge to wastewater treatment technologies, as many of them are non‐biodegradable in nature. Adsorption on granular activated carbon (GAC) has emerged an efficient and economically viable technology for removal of final traces of a broad spectrum of toxic organic compounds from domestic and industrial wastewater. In the present investigation adsorption of some priority organic pollutants, namely phenol, o‐cresol, p‐nitrophenol, m‐methoxyphenol, benzoic acid and salicylic acid on granular activated carbon, was studied in a batch system at laboratory scale. Experiments were carried out to determine adsorption isotherms and kinetics for adsorbate when present in aqueous solutions as single, bi‐ and tri‐solute systems. The commercially available bituminous coal based granular activated carbon Filtrasorb 300 (F‐300) was used as adsorbent. The results indicate that p‐nitrophenol is most strongly adsorbed as compared to other phenols studied. Aqueous phase solubility of the adsorbate plays a deciding role in multi‐component systems as more hydrophobic p‐nitrophenol adsorbs to a greater extent than less hydrophobic phenol, o‐cresol and m‐methoxyphenol. The preferential adsorption of strongly adsorbable solute over a weakly adsorbable one has been observed, as the solutes are competing for the available surface area of the adsorbent for adsorption.     

Extensional viscosity from entrance pressure drop measurements

Extensional rheological properties are important in characterization and processing of polymeric liquids. The use of entrance pressure drop to obtain extensional viscosity is particularly attractive because it can be applied to both low and high viscosity liquids using the Bagley correction obtained from a conventional capillary rheometer.Low density polyethylene of three different melt index values, including IUPAC-X (a different batch of IUPAC-A), and a high density polyethylene were tested using a commercial capillary rheometer. The entrance pressure drop (P _en ) was obtained with a zero-length orifice die with an abrupt contraction. The contraction ratio was 12:1. Predictions from several approximate analyses to calculate the uniaxial extensional viscosity _u (using an axisymmetric contraction) from P _en were compared. These comparisons are summarized in the appendices.Due to the transient nature of contraction flows, _u is also a function of the strain (). This was examined by comparing _u from P _en (Cogswell's analysis was chosen for convenience) with transient extensional viscosity ( _u ⁺) at different magnitudes of from fiber-windup technique (Padmanabhan et al., 1996). _u ⁺ at 3 was found to be close to _u from P _en (using Cogswell's analysis) for two LDPE samples that had fiber-windup data available. The magnitude of the strain in the contraction did not vary with strain rate.Dedicated to the memory of Tasos Papanastasiou     

SUMUDU TRANSFORM IN BICOMPLEX SPACE AND ITS APPLICATIONS

In this paper, we define Sumudu transform with convergence conditions in bicomplex space. Also, we derive some of its basic properties and its inverse. Applications of bicomplex Sumudu transform are illustrated to find the solution of differential equation of bicomplex-valued functions and find the solution for Cartesian transverse electric magnetic (TEM) waves in homogeneous space.     

On null controllability of linear systems with recurrent coefficients and constrained controls

Given a family of time-dependent linear control processes, we study conditions under which local null controllability implies global null controllability. This is done by employing methods of dynamical systems and the Sacker-Sell spectral theory. We show that the above implication holds almost surely for recurrent families provided the spectrum of the associated linear system is contained in (–,0].     

Applications of fuzzy linear programming with generalized LR flat fuzzy parameters

In this paper, the limitations of existing methods to solve the problems of fuzzy assignment, fuzzy travelling salesman and fuzzy generalized assignment are pointed out. All these problems can be formulated in linear programming problems wherein the decision variables are represented by real numbers and other parameters are represented by fuzzy numbers. To overcome the limitations of existing methods, a new method is proposed. The advantage of proposed method over existing methods is demonstrated by solving the problems mentioned above which can or cannot be solved by using the existing methods.