Physicochemical properties of ammonium acetate / propionic acid as a novel deep eutectic solvent and its binary mixtures with water in (298.15-353.15) K range.

Emergence of deep eutectic solvents as potential replacements for volatile organic solvents has attracted interest of the scientific community in diverse fields of applications. Compared to ionic liquids, which exhibit similarity in many respects with this new class of green solvents, deep eutectic solvents (DESs) show low toxicity, and are easy to prepare from cheap and abundantly available starting materials. Knowledge of physicochemical properties of DESs is a prerequisite for their safe applications in technological fields and to understand the nature of interactions present in these systems. Although physicochemical properties of choline chloride based DESs are widely investigated, similar information on ammonium acetate based DESs is scant. In this work, a novel ammonium acetate/propionic acid deep eutectic solvent (AA/PA DES) is reported which is prepared by mixing ammonium acetate (AA) and propionic acid (PA) in the 1:3 mol ratio and characterized by FTIR, 1H and 13C NMR, TGA and DSC techniques. The density (ρ), sound velocity (u), viscosity (η) and conductivity (κ) of the pure DES and its binary mixtures with water are investigated over the entire composition range and temperatures (298.15-353.15) K. The excess properties, VmE, KSE, Δη, and ΔG*E are calculated and corelated using Redlich-Kister equation (RKE). Temperature dependence of conductivity and viscosity is satisfactorily described by the Vogel - Fulcher - Tamman (VFT) equation rather than Arrhenius equation. The pure DES shows a wide electrochemical potential window ranging from - 1000 mV to + 1000 mV, which coupled with its better solubilizing characteristics, could be exploited for electrochemical work.

Physicochemical Properties of Choline Chloride/Acetic Acid as a Deep Eutectic Solvent and Its Binary Solutions with DMSO at 298.15 to 353.15 K.

Deep eutectic solvents (DESs) are considered to play an important role in green chemistry and other technological fields as an alternative to organic solvents. The present study reports measurements of density (ρ), speed of sound (u), dynamic viscosity (η), and electrical conductivity (κ) and investigates physicochemical properties of choline chloride/acetic acid (ChCl/AcA DES) and its binary mixtures with dimethyl sulfoxide (DMSO) over the entire composition and temperature (298.15-353.15 K) range. The density data are well fitted by a second-degree polynomial equation in T. DES/DMSO mixtures exhibit negative excess molar volume and isentropic compressibility deviation with a minimum in respective curves at x1 ≈ 0.15 (x1 is the mole fraction of DES in the mixture), which became deeper with increasing temperature. The ChCl/AcA DES and DMSO curves for excess partial molar volume cross each other at x1 ≈ 0.15, showing that the packing effect is dominant over specific interactions. A similar behavior is observed for excess molar viscosity, showing the minima at x1 ≈ 0.62, and substantiates volumetric results. The temperature dependence of viscosity and conductivity is well described by the Vogel-Fulcher-Tammann (VFT) equation.

From doping to composites: zirconia (ZrO2) modified hematite photoanodes for water splitting.

Herein, a ZrO2 added α-Fe2O3 photoanode that can split water at low applied potential is reported. First, the pristine hematite α-Fe2O3 photoanode was synthesized using an aerosol-assisted chemical vapour deposition (AACVD) method followed by modification with various amounts of ZrO2 (2 to 40%) in the form of thin films on conducting glass substrate. The XRD, Raman spectroscopy and scanning electron microscopy (SEM) analyses confirmed the presence of the monoclinic phase of ZrO2 in the composites with multifaceted particles of compact morphology. The optical analysis showed an increase in the absorbance and variation in band gap of the composites ascribed to the heterogeneity of the material. The photoelectrochemical studies gave a photocurrent density of 1.23 mA cm-2 at 1.23 V vs. RHE for the pristine hematite and remarkably higher value of 3.06 mA cm-2 for the optimized amount of ZrO2 in the modified α-Fe2O3 photoanode. To the best of our knowledge, this is the highest photocurrent reported for a ZrO2 containing photoanode. The optimized composite electrode produced nine times more oxygen than that produced by pristine hematite.

Non-enzymatic amperometric glucose sensing on CuO/mesoporous TiO2 modified glassy carbon electrode.

The present study illustrates the fabrication of a glucose sensing electrode based upon binary composite of copper oxide and mesoporous titanium dioxide on glassy carbon (CuO/TiO2/GCE). The X-ray diffraction, scanning electron microscopy and energy dispersive X-ray analysis evidently showed the phase pure monoclinic CuO nanoparticles and anatase TiO2. N2 adsorption-desorption analysis verified the mesoporosity in TiO2 with specific surface area greater than 105 m2 g-1. Electrochemical impedance spectroscopic analysis proved the remarkable decrease in the charge transfer resistance and facilitation of electron transfer process on the fabricated electrode. The optimum weight ratio of CuO to TiO2 was 1 : 1, and the optimum potential was 0.6 V vs. saturated calomel electrode. The chronoamperometric measurements displayed a detection limit of 1.9 µM, and sensitivities of 186.67 µA mM-1 cm-2 and 90.53 µA mM-1 cm-2 in two linear ranges of 0.05 to 5.2 mM and 5.2 to 20 mM, respectively. The amperometric analysis further showed good reproducibility, high specificity and outstanding stability of the modified electrode.

Melamine-derived N-rich C-entrapped Au nanoparticles for sensitive and selective monitoring of dopamine in blood samples.

Several neurological disorders, including Parkinson's disease, schizophrenia, human immunodeficiency virus infection, and restless leg syndrome, majorly result from disruption in the dopamine (DA) level. Thus, useful information about the treatment and prevention of various genetic majorly mental health problems can be obtained through precise and real-time monitoring of DA. Herein, we report the fabrication of novel N-rich carbon-coated Au nanoparticles (NC@Au-NPs) by deriving from melamine-crosslinked citrate-stabilized Au NPs. NC@Au-NPs offer fast electro-oxidation efficacy towards DA, because of strong electrostatic attraction between negatively charged NC@Au-NPs and positively charged DA. The catalytic efficacy and shelf life of the designed system were further boosted by applying a mixture of polydopamine (PDA) and benzimidazolium-1-acetate ionic liquid (IL) as a sandwich between the working electrode surface (graphitic pencil electrode: GPE) and the designed nanohybrid NC@Au-NPs as a redox mediator. The results indicate that the designed novel NC@Au/PDA-IL/GPE exhibits excellent sensitivity, selectivity, and reproducibility over a wide linear range (50-1000 nm) and a low detection limit of 0.002 µM ± 0.001 as well. The developed sensor was successfully applied to monitor DA in the blood of COVID-19 quarantined patients and pharmaceutical samples with high accuracy, thus suggesting a powerful tool for the diagnosis of mental problems.

Yttrium Doped Copper (II) Oxide Hole Transport Material as Efficient Thin Film Transistor.

This work reports development of yttrium doped copper oxide (Y-CuO) as a new hole transport material with supplemented optoelectronic character. The pure and Y-doped CuO thin films are developed through a solid-state method at 200 °C and recognized as high performance p-channel inorganic thin-film transistors (TFTs). CuO is formed by oxidative decomposition of copper acetylacetonate, yielding 100 nm thick and conductive (40.9 S cm-1 ) compact films with a band gap of 2.47 eV and charge carrier density of ∼1.44×1019  cm-3 . Yttrium doping generates denser films, Cu2 Y2 O5 phase in the lattice, with a wide band gap of 2.63 eV. The electrical conductivity increases nine-fold on 2 % Y addition to CuO, and the carrier density increases to 2.97×1021  cm-3 , the highest reported so far. The TFT devices perform remarkably with high field-effect mobility (µsat ) of 3.45 cm2 V-1 s-1 and 5.3 cm2 V-1 s-1 , and considerably high current-on/off ratios of 0.11×104 and 9.21×104 , for CuO and Y-CuO films, respectively (at -1 V operating voltage). A very small width hysteresis, 0.01 V for CuO and 1.92 V for 1 % Y-CuO, depict good bias stability. Both the devices work in enhancement mode with stable output characteristics for multiple forward sweeps (5 to -60 V) at -1Vg .

Blood loss after intraarticular and intravenous tranexamic acid in total knee arthroplasty.

OBJECTIVE: To compare postoperative blood loss after intravenous and intraarticular tranexamic acid injection in patients of bilateral total knee arthroplasty. METHODS: This comparative randomised study was conducted at Ghurki Trust Teaching Hospital, Lahore, between July 2015 and January 2016, and comprised all patients admitted for bilateral total knee replacement. Patients were randomly divided into two equal groups. Group-A received intraarticular while Group-B received intravenous injection of 1.5 gmtranexamic acid. All data was analysed using SPSS 17. RESULTS: The total 140 patients were divided into two equal groups of 70(50%) each. In Group-A there were 32(45.7%) males and 38(54.3%) females, while in Group-B, there were 28(40%) males and 42(60%) females. The mean ages were 64.39±9.07 years in Group-A and 63.30±9.51 years in Group B. Blood loss in Group-A was significantly lower than Group-B (p=0.01).. CONCLUSIONS: Intraarticular administration of tranexamic acid was more effective than intravenous administration in terms of reducing blood loss.

Synthesis and bioelectrochemical behavior of aromatic amines.

Four aromatic amines 1-amino-4-phenoxybenzene (A1), 4-(4-aminophenyloxy) biphenyl (A2), 1-(4-aminophenoxy) naphthalene (A3) and 2-(4-aminophenoxy) naphthalene (A4) were synthesized and characterized by elemental, spectroscopic (FTIR, NMR), mass spectrometric and single crystal X-ray diffraction methods. The compounds crystallized in monoclinic crystal system with space group P21. Intermolecular hydrogen bonds were observed between the amine group and amine/ether acceptors of neighboring molecules. Electrochemical investigations were done using cyclic voltammetry (CV), square wave voltammetry (SWV) and differential pulse voltammetry (DPV). CV studies showed that oxidation of aromatic amines takes place at about 0.9 V (vs. Ag/AgCl) and the electron transfer (ET) process has irreversible nature. After first scan reactive intermediate were generated electrochemically and some other cathodic and anodic peaks also appeared in the succeeding scans. DPV study revealed that ET process is accompanied by one electron. DNA binding study of aromatic amines was performed by CV and UV-visible spectroscopy. These investigations revealed groove binding mode of interaction of aromatic amines with DNA.

Radical scavenging propensity of Cu2+, Fe3+ complexes of flavonoids and in-vivo radical scavenging by Fe3+-primuletin.

Cu2+ and Fe3+ complexes of three flavonoids (morin or mo, quercetin or quer and primuletin or prim) were synthesized with the objective of improving antioxidant capacities of flavonoids. The radical scavenging activities of pure flavonoids and their metal complexes were assayed to monitor their tendencies towards sequestering of radicals at physiological conditions. The scavenger potencies of metal-flavonoid complexes were significantly higher than those of the parent flavonoids. Further, influence of the solvent polarity on the radical capturing by flavonoids and their metal complexes was in favor for the polar solvent. Fe3+-prim displayed its radical scavenging ability via up gradation of CAT and SOD activities in in-vivo antioxidant assays.

Synthesis, biological and electrochemical evaluation of novel nitroaromatics as potential anticancerous drugs.

Nitroaromatics i.e. 1-nitro-4-phenoxybenzene (1), 4-(4-nitrophenyloxy) biphenyl (2), 1-(4-nitrophenoxy) naphthalene (3) and 2-(4-nitrophenoxy) naphthalene (4) were synthesized by Williamson etherification and characterized by elemental analysis, FTIR, NMR ((1)H, (13)C), UV-visible spectroscopy, mass spectrometry and single crystal X-ray diffraction analysis. Their brine shrimp cytotoxicity resulted in LD50 values <1 µg/mL indicating significant antitumor activity with IC50 values ranging from 29.0 to 8.4 µg/mL. They are highly active in protecting DNA against hydroxyl free radicals in a concentration dependent manner. Voltammetric studies showed one electron reversible reduction at a platinum electrode with diffusion coefficient (Do) values of the order ~10(-6)-10(-7) cm(2)s(-1). Strong interaction with the human blood DNA through intercalative mode was contemplated through electrochemical and UV-visible spectroscopic studies which are in agreement with the conclusions drawn from biological analysis, unravelling the potential anticancerous nature of the synthesized compounds.

An investigation into membrane bound redox carriers involved in energy transduction mechanism in Brevibacterium linens DSM 20158 with unsequenced genome.

Brevibacterium linens (B. linens) DSM 20158 with an unsequenced genome can be used as a non-pathogenic model to study features it has in common with other unsequenced pathogens of the same genus on the basis of comparative proteome analysis. The most efficient way to kill a pathogen is to target its energy transduction mechanism. In the present study, we have identified the redox protein complexes involved in the electron transport chain of B. linens DSM 20158 from their clear homology with the shot-gun genome sequenced strain BL2 of B. linens by using the SDS-Polyacrylamide gel electrophoresis coupled with nano LC-MS/MS mass spectrometry. B. linens is found to have a branched electron transport chain (Respiratory chain), in which electrons can enter the respiratory chain either at NADH (Complex I) or at Complex II level or at the cytochrome level. Moreover, we are able to isolate, purify, and characterize the membrane bound Complex II (succinate dehydrogenase), Complex III (menaquinone cytochrome c reductase cytochrome c subunit, Complex IV (cytochrome c oxidase), and Complex V (ATP synthase) of B. linens strain DSM 20158.

Formation of low density hydrous iron oxide via conformal transformation of MIL-53(Fe).

Hydrous iron oxide materials with a predefined shape, photo-electrochemical activity, low density (estimated to be 0.32 g cm(-3)), and high fractal porosity (BET ca. 117 m(2) g(-1)) are formed via internal hydrolytic transformation of the crystalline metal-organic framework MIL-53(Fe) in dilute aqueous hydroxide.

Voltammetric determination of antioxidant character in Berberis lycium Royel, Zanthoxylum armatum and Morus nigra Linn plants.

The antioxidant activity potential of three different plant extracts was investigated against superoxide anion radical while employing cyclic voltammetry technique. The plants Berberis lyceum Royle, Morus nigra Linn and Zanthoxylum armatum were selected because of their potential use in the traditional medicine. The voltammetric response of the electrochemically generated superoxide anion radial in DMSO was monitored in the absence and presence of the plat extracts. The decrease in the current was interpreted in terms of antiradical activity of the added extract. The thermodynamic feasibility of the radical scavenging by extracts was accounted in terms of antioxidant activity coefficient (K(ao)) and standard Gibbs free energy (ΔG(o)). The values of K(ao) and ΔG(o) ranged from 1.0 x 102 to 57 x 102 L(-1) and -18 to -27 kJmol(-1), respectively. The possible mechanism of the antioxidant reaction was regarded as E(r)C(i) mechanism i.e. reversible electron transfer followed by hydrogen atom transfer- an irreversible chemical reaction.

Synthesis, structural characterization and in vitro cytotoxicity and anti-bacterial activity of some copper(I) complexes with N,N'-disubstituted thioureas.

A series of copper(I) complexes of N,N'-disubstituted thioureas, [C(6)H(5)CONHCSNHR]Cu(I)Cl where R=C(6)H(5) (1a), 2-ClC(6)H(4) (2a), 3-ClC(6)H(4) (3a), 4-ClC(6)H(4) (4a), 2,3-Cl(2)C(6)H(3) (5a), 2,4-Cl(2)C(6)H(3) (6a), 2,5-Cl(2)C(6)H(3) (7a), 2,6-Cl(2)C(6)H(3) (8a), 3,4-Cl(2)C(6)H(3) (9a) and 3,5-Cl(2)C(6)H(3) (10a) have been synthesized. These complexes (1a-10a) have been characterized by elemental analyses, IR, (1)H and (13)C NMR spectroscopy, cyclic voltammetry and single crystal XRD for 1a and 8a, and for ligand 7. The X-ray crystal structures reveal that the complexes 1a and 8a are mononuclear in the solid state in which the copper atoms adopt a distorted tetrahedral geometry. In both the cases, the neutral N,N'-disubstituted thiourea ligands have been coordinated to the Cu(I) through the sulphur atom in a terminal mode. The complexes have been screened for their in vitro cytotoxic activity in human cell lines carcinomas A498 (Renal), EVSA-T (Breast), H226 (Lung), IGROV (Ovarian), M19 (Melanoma-Skin), MCF-7 (Breast) and WIDR (Colon). They show a moderate cytotoxicity against these seven human cancer cell lines comparable to that of the less active standard chemotherapeutic drugs used for comparison. They were also screened for their anti-bacterial activity and were found less active than the standard drug Imipenem.