Equimolar Ratio Research Articles

OBTAINING AND STUDYING THE PROPERTIES OF IRON AND SILICON-CONTAINING MAX-PHASES BY THE METHOD OF SELF-PROPAGАТING HIGH-TEMPERATURE SYNTHESIS

The paper discusses the preparation and properties of a new class of multifunctional composites, which are obtained by high-temperature self-propagating synthesis (SHS) of various metal powders. The class of such composites includes MAX phases. The aim of this work is to synthesize a MAX-phase of the (Fe,Ti)3(Si,Al)C2 type by self-propagating high-temperature synthesis of a mixture of Ti, FeSi, Al and carbon in equimolar ratios. The synthesized main phase exhibits magnetic properties due to its iron and silicon content. Experiments have shown that from a mixture of powders of ferrosili¬co¬n, titanium, aluminum, carbon by the SHS method, it is possible to obtain a powdery base mass containing 93% of the MAX-phase composition of the type (Fe,Ti)3(Al,Si)C2 by mass, and 7% embedded in rich crystals iron Fe5Si3, Fe3Si and FeSi, which impart magnetic properties to the material, also contain Ti5Si2 and TiC-2% by weight insoluble in the main phase. In order to accurately assess the size distribution of embedded products in the main phase, a new analysis method was chosen - modern automatic microradiographic analysis (MRSA). The principle of the analysis was presented. The microstructure of such a MAX material, synthesized by powder metallurgy (SHS synthesis) methods, has a layered, laminate nature and can become a good raw material for further alloying of this compound with various metals for the development of powder metallurgy in Armenia.

Alteration to the Skin Ceramide Profile Following Broad-Spectrum UV Exposure.

The epidermal stratum corneum (SC) lipid matrix, principally consisting of an equimolar ratio of ceramides, free fatty acids, and cholesterol, plays a crucial role in maintaining proper skin barrier function. Conditions which impair barrier integrity, such as in atopic dermatitis, correlate with the alternation of key ceramide subclasses and reduced chain length of acyl moieties. However, there is limited knowledge about the impact of unprotected repeat sun exposure on the skin lipid composition, especially ceramide profiles.This study investigated the effects of ultraviolet (UV) radiation on the ceramide profile using both an ex vivo skin and a clinical model. Lipidomic analysis of UV-exposed skin showed shifts to the composition of ceramide subclasses essential in repairing and strengthening the SC barrier (including CER1[EOS], CER3[NP], and CER6[AP]) and reduced very long-chain acyl moieties. Gene expression analysis and immunohistochemical staining of key enzymes (aSMase, DES1, CerS5, CerS3) suggested that lipid alterations can be attributed to changes within the ceramide biosynthesis process. Topical application of ceramide-containing suncare products help maintain SC-essential ceramide subclasses and proper ceramide chain length, demonstrating the importance of proper photoprotection to maintain healthy skin barrier and ceramide quality during daily sun exposure. J Drugs Dermatol. 2022;21(1):77-85. doi:10.36849/JDD.6331.

ИЗУЧЕНИЕ КОРРОЗИОННОЙ СТОЙКОСТИ ВЫСОКОЭНТРОПИЙНОГО СПЛАВА Al0,5CoCrFeNi1,6Ti0,7 В МОРСКОЙ ВОДЕ

High-entropy alloys (HEAs) are a relatively new type of alloys and interest is constantly growing. Unlike traditional alloys based on one or two main components, HEAs include five or more components in close to equimolar ratios. It is known that a number of HEAs exhibit a high level of useful properties. Such alloys combine high strength and ductility, increased fatigue resistance, high hardness and wear resistance, and high thermal stability. The development of new compositions and the study of the properties of the obtained high-entropy alloys are currently topical materials science problems. The creation of corrosion-resistant HEAs and the study of their behavior in aqueous solutions of alkalis, acids and salts is justified by the possibility of applying coatings on products operated in aggressive aqueous solutions, including sea water. This work is devoted to the study of the corrosion resistance of the high-entropy alloy Al0.5CoCrFeNi1.6Ti0.7 in an aqueous solution – an analogue of sea water for 93 days in order to determine the long-term stability of this alloy when operating under the conditions of the Northern Sea Route. It is shown that this alloy has a complex multiphase structure, which does not worsen the corrosion resistance when operating in sea water. HEAs Al0.5CoCrFeNi1.6Ti0.7 demonstrates the change in mass according to the parabolic law. During the entire test period, the weight gain was about 2.7 mg/cm2. Most of the surface of the investigated alloy after testing is covered with a thin oxide film; the composition of the film is dominated by oxides of titanium, chromium and nickel.

Influence of redox initiator component ratios on the emulsion copolymerisation of vinyl acetate and neodecanoic acid vinyl ester.

Redox initiated emulsion polymerisation of vinyl acetate and neodecanoic acid vinyl ester was investigated at temperatures ranging from −1 °C to 87 °C (initiation temperature between −1 °C and 60 °C), using varying molar ratios of the following redox components: l-ascorbic acid, tert-butyl hydroperoxide and ammonium iron(iii) sulfate dodecahydrate as a catalyst. The high flexibility of redox initiators enables product properties, as well as space-time-yield, to be adjusted as required. Polymers being products by process, it was presumed that modifying the conversion rate would lead to a different product. However, it was shown that the reaction rate is adjustable by varying the catalyst amount without changing the product properties, such as molecular weight, particle size, glass transition temperature and polymer structure, while reducing the overall process time by 40–86% (at equimolar ratios of reducing and oxidising agent). In contrast, variation of the tert-butyl hydroperoxide content resulted in changes of the molecular weight. The influence of the initiation temperature and of the redox system on the reaction rate was determined, enabling control over the reaction rate in the whole temperature range. Meanwhile, overall process times of approximately 2–240 min and high conversions of 90–99% could be achieved. Statistical modelling confirmed the results and facilitated predictions, enabling the conversion rate to be adjusted to the desired properties. The possibility of being able to adjust the conversion rate and product properties independently of each other creates additional degrees of freedom in process design.

Methyl formate and dimethyl ether electro-oxidation on Pt[sbnd]Pd[sbnd]Sn catalyst supported on carbon nanotube decorated with carbon dots

In this work, methyl formate (MF) and dimethyl ether (DME) electro-oxidation was studied on equimolar ratio PtPdSn catalyst supported on Vulcan Carbon XC-72, carbon nanotubes (CNT), and CNT–nitrogen-doped carbon dots (NCDs) composite. The ternary catalyst was synthesized by the ethylene glycol-assisted thermal reduction method and NCDs were synthesized by a hydrothermal method in the presence of CNT to form CNT-NCDs composite, in which the NCDs are incorporated onto the CNT surface. The activity of the catalyst in the oxidation of MF and DME was analyzed using cyclic voltammetry and chronoamperometry techniques. The ternary catalyst supported on CNT-NCDs composite (Pt1Pd1Sn1/CNT-NCDs) showed a peak oxidation current of 75 mA/mg and 365 mA/mg for DME and MF, respectively, highest among the studied Pt1Pd1Sn1/XC-72 and Pt1Pd1Sn1/CNT. The onset potential of DME on Pt1Pd1Sn1/CNT-NCDs catalyst shifted negatively by ∼200 mV compared to PtRu. Irrespective of the support material, the ternary catalysts showed a significant negative shift in the onset and peak potential of COad oxidation compared with commercial PtRu. The oxidation behavior of MF was studied in conjugation with its hydrolysis products methanol, formic acid, and mixed fuel (formic acid + methanol) solution, which disapproves the earlier proposed acid-catalyzed hydrolysis of MF to a significant degree during the electrochemical experiment. Hence, the CNT-NCDs supported ternary catalyst showed high catalytic activity and stability for electro-oxidation of DME and MF.

Diglyme-Incorporated Gelled Polymer: An Efficient Quasi-Solid-State Electrolyte for Sodium-Ion Batteries

Glyme-based electrolytes have been gaining increasing attention in sodium-ion batteries (NIBs) for their attractive electrochemistry involving good complexation ability with Na-ions, high electrochemical stability, good transport characteristics, low volatility, and high safety. Here, we report a flexible and freestanding sodium-ion conducting gel polymer electrolyte containing an equimolar ratio of Na-salt NaTFSI and diglyme (G2), referred to as a solvate ionic liquid (SIL), immobilized inside host polymer poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP). Fourier-transform infrared (FTIR) and Raman analyses are employed to investigate the conformational evolutions in PVdF-HFP on incorporating G2 and NaTFSI, whereas structural changes are observed using X-ray diffraction. The electrochemical investigations on the electrolyte revealing a wide electrochemical stability window (∼5.2 V) versus Na/Na+, high room-temperature ionic conductivity (∼1.12 × 10–3 S cm–1), and a large Na+ transference number (tNa+ ∼ 0.58) along with thermal stability up to ∼100 °C render the electrolyte suitable for Na-storage applications. The Na deposition/extraction tests over a long period indicate excellent cyclic stability of the cells, revealing low and stable polarization with values limited to ±19 mV at a current density of 0.01 mA cm–2. Further, the prepared solvate ionic liquid-incorporated gel polymer electrolyte (SIL-GPE) is tested in Na-ion battery cells comprising Na0.7CoO2 cathode using galvanostatic charge–discharge cycling, with a first discharge capacity of ∼91.76 mA h g–1 at a 0.05C rate. Studies indicate a class of gel polymer electrolytes based on solvate ionic liquids, suitable for Na-storage applications.

Technological Aspects of Highly Selective Synthesis of Allyloxyalcohols—New, Greener, Productive Methods

Allyl ethers bearing free hydroxyl groups of CH2=CH-CH-O-A-OH type (hydroxyalkyl allyl ethers, allyloxyalcohols) are valuable chemicals in many environmentally friendly industrial applications. The development of technologically attractive methods for their production is necessary. The two pathways (L-L PTC and non-catalytic solvent-free conditions) were optimized for the highly selective and yield synthesis of 4-allyloxybutan-1-ol. Improvements in the PTC method (50% NaOH(aq), the equimolar ratio of NaOH to diol, cyclohexane as solvent) with a new highly selective and effective PT catalyst, i.e., Me(n-Oct)3N+Br− (0.3 mol%), resulted in 88% yield and 98% selectivity of 4-allyloxybutan-1-ol with minimal formation of allyl chloride hydrolysis by-products (<1%). In turn, application of non-catalytic solvent-free conditions and the change in the key substrate with an excess of diol and use of solid NaOH solely led to a mono-O-allylation product with an excellent yield of 99% in a relatively short reaction time (3.5 h), with trace amounts of by-products (<0.1%). This sustainable method is perfectly suitable for the synthesis on a larger scale (3 moles of the key substrate) and for the full O-allylation process.

Synthesis, spectral characterization, X-ray crystallography and biological evaluations of Pd(II) complexes containing 4(N)-substituted thiosemicarbazone

Four new Pd(II) complexes have been synthesized by reacting equimolar ratio of [PdCl2(PPh3)2] and 4(N)-substituted 4,6-dimethoxysalicylaldehyde thiosemicarbazone ligands in toluene and characterized by UV-Vis, IR and NMR. Single crystal X-ray diffraction studies of 2 and 3 revealed that both the complexes have distorted square planar geometry around palladium ion, in which the ligand coordinates through NS and form five-membered rings. Interaction of complexes with calf thymus DNA (CT-DNA) has been examined by absorption titration, suggesting intercalation. Binding of complexes with Bovine serum albumin (BSA) protein using UV-Visible and fluorescence spectroscopic methods indicated strong binding of complexes to BSA. The antioxidant properties of all the complexes showed moderate activity as compared to standard BHT. The cytotoxicities of the Pd(II) complexes were investigated in vitro against both lung cancer (A549) and human breast cancer (MCF-7) cell lines by using MTT assay and by using (AO/EB and DAPI) staining method for cytological changes in cell lines.

Synthesis, spectroscopic characterization, computational studies, theoretical investigation of NLO properties and antibacterial activities of mixed ligand complexes of Co(II) and Cu(II)

The reaction of Schiff base 2-(4-(dimethylamino)benzylideneamino)phenol (DBAP) and diethylenetriamine/ethylenediamine with cobalt(II) and copper(II) metal ion in equimolar ratio afforded mixed ligand complexes [M(DBAP)(L)Cl(H2O)n] (1–4), where M = Co(II) 1, 2; Cu(II) 3, 4; L = diethylenetriamine (1, 3); n = 0 and ethylenediamine (2, 4); n = 1. All the newly synthesized complexes were characterized by elemental analysis, spectroscopic techniques viz., UV-vis, FT-IR, ESR, PXRD and mass spectrometry. The influence of chelation of cobalt(II) and copper(II) ion on nonlinear optical properties of Schiff base (DBAP) were examined with DFT study. The polarizability (α0) and first-order hyperpolarizability (β) of ligand and their metal complexes were calculated and compared with reference molecule p-nitroaniline. The hyperpolarizability of Schiff base and their metal complexes show a good nonlinear optical behavior. Theoretical investigation of the complexes was performed by DFT using B3LYP level of theory on the basis set 6-31 G (d, p)/LanL2DZ. On the basis of spectroscopic data and DFT computation, a six-coordinate geometry is tentatively proposed around the metal ion. In vitro antibacterial activities of these complexes were also screened against V. cholerae and E. coli, and found to have good antibacterial activity.

Methylammonium Lead Tri-Iodide Perovskite Solar Cells with Varying Equimolar Concentrations of Perovskite Precursors

During recent years, power conversion efficiencies (PCEs) of organic-inorganic halide perovskite solar cells (PSCs) have shown remarkable progress. The emergence of various thin film deposition processes to produce perovskite films, notably using solution processing techniques, can be credited in part for this achievement. The engineering of chemical precursors using solution processing routes is a powerful approach for enabling low-cost and scalable solar fabrication processes. In the present study, we have conducted a systematic study to tune the equimolar precursor ratio of the organic halide (methylammonium iodide; MAI) and metal halide (lead iodide; PbI2) in a fixed solvent mixture of N,N-dimethylformamide (DMF):dimethylsulfoxide (DMSO). The surface morphology, optical characteristics, and crystallinity of the films produced with these four distinct solutions were investigated, and our analysis shows that the MAI:PbI2 (1.5:1.5) film is optimal under the current conditions. The PSCs fabricated from the (1.5:1.5) formulation were then integrated into the n-i-p solar cell architecture on fluorine-doped tin oxide (FTO) substrates, which exhibited a PCE of ~14.56%. Stability testing on this PSC device without encapsulation at 29 °C (ambient temperature) and 60% relative humidity (RH) under one-sun illumination while keeping the device at its maximum power point showed the device retained ~60% of initial PCE value after 10 h of continuous operation. Moreover, the recombination analysis between all four formulations showed that the bimolecular recombination and trap-assisted recombination appeared to be suppressed in the more optimal (1.5:1.5) PSC device when compared to the other formulations used in the n-i-p PSC architecture.

Electron Delocalization in Spectroelectrochemically and Computationally Characterized [Pt{(p-BrC6F4)NCH═C(Cl)NEt2}Cl(py)]+ Formed by Electrochemical Oxidation of [PtII{(p-BrC6F4)NCH═C(Cl)NEt2}Cl(py)

[Pt{(p-BrC6F4)NCH═C(Cl)NEt2}Cl(py)] (1Cl) is the product of the hydrogen peroxide oxidation of the PtII anticancer agent [Pt{(p-BrC6F4)NCH2CH2NEt2}Cl(py)] (1). Insights into electron delocalization and bonding in [Pt{(p-BrC6F4)NCH═C(Cl)NEt2}Cl(py)]+ (1Cl+) obtained by electrochemical oxidation of 1Cl have been gained by spectroscopic and computational studies. The 1Cl/1Cl+ process is chemically and electrochemically reversible on the short time scale of voltammetry in dichloromethane (0.10 M [Bu4N][PF6]). Substantial stability is retained on longer time scales enabling a high yield of 1Cl+ to be generated by bulk electrolysis. In situ IR and visible spectroelectrochemical studies on the oxidation of 1Cl to 1Cl+ and the reduction of 1Cl+ back to 1Cl confirm the long-term chemical reversibility. DFT calculations indicate only a minor contribution to the electron density (13%) resides on the Pt metal center in 1Cl+, indicating that the 1Cl/1Cl+ oxidation process is extensively ligand-based. Published X-ray crystallographic data show that 1Cl is present in only one structural form, while NMR data on the dissolved crystals revealed the presence of two closely related structural forms in an almost equimolar ratio. Solution-phase EPR spectra of 1Cl+ are consistent with two closely related structural forms in a ratio of about 90:10. The average g value for the frozen solution spectra (2.0567 for the major species) is significantly greater than the 2.0023 expected for a free radical. Crystal field analysis of the EPR spectra leads to an estimate of the 5d(xz) character of around 10% in 1Cl+. Analysis of X-ray absorption fine structure derived from 1Cl+ also supports the presence of a delocalized singly occupied metal molecular orbital with a spin density of approximately 17% on Pt. Accordingly, the considerably larger electron density distribution on the ligand framework (diminished PtIII character) is proposed to contribute to the increased stability of 1Cl+ compared to that of 1+.

Alteration to the Skin Ceramide Profile Following Broad-Spectrum UV Exposure

The epidermal stratum corneum (SC) lipid matrix, principally consisting of an equimolar ratio of ceramides, free fatty acids, and cholesterol, plays a crucial role in maintaining proper skin barrier function. Conditions which impair barrier integrity, such as in atopic dermatitis, correlate with the alternation of key ceramide subclasses and reduced chain length of acyl moieties. However, there is limited knowledge about the impact of unprotected repeat sun exposure on the skin lipid composition, especially ceramide profiles.This study investigated the effects of ultraviolet (UV) radiation on the ceramide profile using both an ex vivo skin and a clinical model. Lipidomic analysis of UV-exposed skin showed shifts to the composition of ceramide subclasses essential in repairing and strengthening the SC barrier (including CER1[EOS], CER3[NP], and CER6[AP]) and reduced very long-chain acyl moieties. Gene expression analysis and immunohistochemical staining of key enzymes (aSMase, DES1, CerS5, CerS3) suggested that lipid alterations can be attributed to changes within the ceramide biosynthesis process. Topical application of ceramide-containing suncare products help maintain SC-essential ceramide subclasses and proper ceramide chain length, demonstrating the importance of proper photoprotection to maintain healthy skin barrier and ceramide quality during daily sun exposure. J Drugs Dermatol. 2022;21(1):77-85. doi:10.36849/JDD.6331Broad-Spectrum UV Exposure

Spectrophotometric studies of charge-transfer complexes formed with ions N,N’-alkyldiyl-bis(pyridinium) derivatives and iodide

The charge-transfer complexes (CTC) between electron donor iodide and pyridinium dimers and monomers as acceptors have been studied spectrophotometrically in acetonitrile, DMSO and water. The dimers were: N,N'-alkyldiyl-bis(4-cyanopyridinium) and N,N'-alkyldiyl-bis(2-bromopyridinium), and the monomers were: N-alkyl-4-cyanopyridinium and N-alkyl-2-bromopyridinium, bridged by n methylene spacers. The formation constant (KCTC), molar absorptivity (εCTC), fluorescence-quenching constant (KSV) were determined. The results indicate that the stoichiometry of the CTC for dimers and monomers is 1:1 (equimolar ratio), and its formation is favored for dimers more than for monomers, especially dimers with short methylene spacers forming a “sandwiched type-complex” in which the iodide is close to the two pyridinium rings. Solvents with low polarity favored the complex, which was destroyed by the presence of water. The experimental studies were complemented with theoretical studies with quantum mechanics (QM) calculations using density functional theory (DFT) and molecular mechanics (MM) simulations with Molecular Dynamics for identify the most stable conformers in acetonitrile solution. The electronic excitations were calculated with sequential QM/MM hybrid method, showing a charge-transfer wavelength in agreement with the UV–Vis absorption spectra obtained experimentally. It confirms the “sandwiched type-complex” conformers favoring the interaction of the iodide with one pyridinium rings and simultaneously forming one, or two, hydrogen bonds with the alkyl chain and additionally, for the case of dimers, with the other pyridinium ring.

Lanthanide rhenium oxide single crystals from hydrothermal fluids: Synthesis and Structures of Ln2ReO5 (Ln = Pr, Nd), Ln3ReO7 (Ln = Gd and Tb) and Ln6ReO12 (Ln = Yb, Lu)

The phase space involving reactions of rare earth oxides and ReO2 was examined under high temperature hydrothermal conditions (650 ​°C/200 ​MPa), focusing on reactions containing either excess (3:1) or equimolar ratios of lanthanide oxides to ReO2. The products were generally isolated as high quality single crystals and characterized by single crystal X-ray diffraction, in many cases for the first time. The systematic variation of the size of the lanthanide ions had a significant effect on the final product distribution, and a wide range of materials was obtained. In particular, the synthesis of new members of the Ln2ReO5 series based on the larger lanthanides Pr and Nd enabled the structural transition point to be pinpointed between structure types having eclipsed and staggered Re2O8 dimers with a Re–Re triple bond. In the moderately sized lanthanides, a new monoclinic polymorph of Ln3ReO7 (Ln ​= ​Gd, Tb) was obtained, featuring alternating long and short Re–Re bonds in edge-sharing rhenium oxide chains. Among the smallest lanthanides, the Ln6ReO12 composition was characterized for Yb and Lu. A variety of rhenium oxidation states were observed and these were supported by XPS characterization.

Acetosolv pretreatment of wood for biorefinery applications

The production of biofuels and biochemicals requires a pretreatment to cleave the composite-like structure of lignocellulosic biomass and thus facilitate further conversion. In the case of liquid-based pretreatment, it is important to know which pretreatment liquids allow for an effective conversion of biomass. For the development of effective pretreatment strategies, simple criteria for a fast evaluation of pretreatment results are advantageous. In this study, we use the example of acetosolv pretreatment of beech wood to explore the influence of composition of the employed acetosolv liquids. To this end, we investigate pretreatment phenomena on different scales including macroscopic disintegration, overall mass balances and compositional changes of beech wood. We relate the investigated phenomena with the type and amount of catalyst acid as well as water content of the employed acetosolv liquids. The results show that disintegration increases with both a higher concentration and acidity of the catalyst acid, while excessive disintegration can be balanced by an increased water content up to equimolar ratios of water and acetic acid. Furthermore, an increasing disintegration correlates with an increasing non-recovered fraction up to a maximum of 40 wt%. The non-recovered fraction in turn linearly depends on the amount of removed hemicellulose and lignin. Overall, a low lignin content together with complete disintegration after pretreatment in acetosolv liquids with a high water content allows for increased sugar yields in subsequent enzymatic hydrolysis. Thus, disintegration and non-recovered fraction serve as a simple indicator for a first assessment of pretreatment effectiveness.

Optoelectronic, photocatalytic and biological studies of mixed ligand Cd(II) complex and its fabricated CdO nanoparticles

• Synthesis of Azo-Schiff base ligand and its mixed ligand Cd(II) complex with 8- Hydroxy Quinoline. • Fabrication of CdO nanoparticles from synthesized mixed ligand Cd(II) complex. • Complex and nanoparticles used as the photocatalyst for the degradation of acid red dye. • Optoelectronic studies of the compounds were analyzed by cyclic voltammetry and photoluminescence. • DNA binding and cleavage studies were conducted for mixed ligand Cd(II) complex. This existing examination focuses on the synthesis of the novel Azo-imine ligand obtained from the simple condensation of 2-hydroxy-3-methoxy benzaldehyde with 4-amino-azobenzene and its Mixed ligand Cd(II) Complex was synthesized using Azo-imine ligand as primary ligand and 8-hydroxy Quinoline as a secondary ligand in the equimolar ratio. Further, the obtained complex was fabricated as CdO through the thermal decomposition method. The obtained compounds were illuminated by the different spectroscopic techniques and the formation of the nanoparticles was confirmed by Powder-XRD and TEM Analysis. The CV and PL properties of the synthesized compounds have been investigated in different conditions. Photoemission wavelength at 481 nm and 498 nm specified that both Cd(II) complex and CdO enhance strong Blue luminescence on photoemission. From the electrochemical studies, the reduction of Cd(II) was found to be Quise-reversible in a 0.1 M KOH and give evidence for the formation of a mixed ligand Cd(II) complex in the molar ratio 1:1:1. For Acid red dye under Visible light, CdO shows effective photodegradation than the mixed ligand Cd(II) complex. The DNA Binding study of mixed ligand Cd(II) complex with CT-DNA was investigated by the absorption spectroscopy method and the results gave the evidence for the classical intercalation. The DNA Cleavage results are the indication that the metal complex has good costs in the cleavage of pUC -18 DNA. Further, the antibacterial study of the compounds shows satisfactory results against Gram-positive ( Staphylococcus Aureus ) and Gram-negative ( Proteus ) bacterial strains.

Assembly of the Non-Canonical Myo9a-RhoGAP and RhoA·GDP Transition State Complex in the Presence of MgF3.

Myo9a is an actin-based molecular motor with a RhoGAP domain in its C-terminal tail. It plays a role in a variety of biological processes, such as in regulating the immune response, neuron development, and cancer progression, and its deregulation can lead to the development of disease conditions. Myo9a acts mainly via its RhoGAP domain. In the current study, we used a pET32a vector with an N-terminal Trx-His6 tag to express Myo9a-RhoGAP in a soluble form. High-purity Myo9a-RhoGAP protein was obtained after two rounds of Ni2+ affinity and size-exclusion chromatography. We mixed Myo9a-RhoGAP and RhoA in equimolar ratios in the presence of 5mM MgCl2 and 20mM NaF to achieve a stable RhoA GTP hydrolysis transition state complex. Analytical gel filtration and SDS-PAGE were used to verify complex formation. ITC and GAP assays suggested that Myo9a-RhoGAP could bind to RhoA and accelerate RhoA GTP hydrolysis in vitro. We purified the soluble Myo9a-RhoGAP protein with GAP activity and achieved the Myo9a-RhoGAP/RhoA·GDP/MgF3- complex assembly in vitro for the first time. The data may provide novel insights into Myo9a structure and function.

Deuterium Oxide Labeling for Global Omics Relative Quantification (DOLGOReQ): Application to Glycomics.

A new relative quantification strategy for glycomics, named deuterium oxide (D2O) labeling for global omics relative quantification (DOLGOReQ), has been developed based on the partial metabolic D2O labeling, which induces a subtle change in the isotopic distribution of glycan ions. The relative abundance of unlabeled to D-labeled glycans was extracted from the overlapped isotopic envelope obtained from a mixture containing equal amounts of unlabeled and D-labeled glycans. The glycan quantification accuracy of DOLGOReQ was examined with mixtures of unlabeled and D-labeled HeLa glycans combined in varying ratios according to the number of cells present in the samples. The relative quantification of the glycans mixed in an equimolar ratio revealed that 92.4 and 97.8% of the DOLGOReQ results were within a 1.5- and 2-fold range of the predicted mixing ratio, respectively. Furthermore, the dynamic quantification range of DOLGOReQ was investigated with unlabeled and D-labeled HeLa glycans mixed in different ratios from 20:1 to 1:20. A good correlation (Pearson's r > 0.90) between the expected and measured quantification ratios over 2 orders of magnitude was observed for 87% of the quantified glycans. DOLGOReQ was also applied in the measurement of quantitative HeLa cell glycan changes that occur under normoxic and hypoxic conditions. Given that metabolic D2O labeling can incorporate D into all types of glycans, DOLGOReQ has the potential as a universal quantification platform for large-scale comparative glycomic experiments.

Supramolecular Assembly of Morpholin-4-ium hydroxy(diphenyl)acetate—Structural, Spectral and Nonlinear Optical Analyses

A supramolecular assembly of Morpholin-4-ium hydroxy(diphenyl)acetate (MHA) was synthesized by acquiring morpholine and benzilic acid in equimolar ratio via solvent vaporization technique using methanol as a solvent. The structure of MHA was analyzed by single-crystal X-ray diffraction analysis, which confirms that the crystal is crystallized in a monoclinic crystal system with C2/c centrosymmetric space group. The molecule was stabilized via NH….O and OH..O supramolecular assembly networks. Close contacts are observed over dnorm surface with red spots, from Hirshfeld analysis which are owing to OH…O and NH…O intermolecular interactions. 1H NMR analysis confirmed the migration of proton from benzilic acid to morpholine and in 13C NMR analysis, the signal at δ 176.36 ppm confirmed the presence of highly deshielded carboxylate carbon in the molecule. The vibrational frequencies associated with the functional groups in the MHA crystal are estimated using Fourier transform infrared spectroscopy. Refractive index (n) and extinction coefficient (K), bandgap, optical conductivity (σop), electrical conductivity (σel), optical susceptibility (χop) and polarization (P) were estimated using UV–vis spectroscopy. Fluorescence peaks were observed at 334 and 380 nm via photoluminescence spectroscopy. The third order nonlinear optical properties were obtained using Z-scan studies. The Z-scan curve in the closed aperture configuration indicates the change in refractive index of the MHA crystal with a strong self-defocusing effect.

Heteroleptic Palladium(II) Complexes of Thiazolinyl‐picolinamide Derived N∩N∩N Pincer Ligand: An Efficient Catalyst for Acylative Suzuki Coupling Reactions

AbstractSynthesis, reactivity, characterization, and catalytic activities of a series of palladium(II) complexes containing the thiazolinyl‐picolinamide derived pincer ligand is reported. Treatment of 2‐aminobenzonitrile with cysteamine and subsequent treatment with 2‐picolinic acid afforded the thiazolinyl‐picolinamide derived tridentate pincer ligand N∩N∩N (2). Treatment of 2 either with (COD)PdCl2 or PdCl2 in 1 : 1 ratio afforded the palladium(II) complex [(κ3‐N∩N∩N)PdCl] (3). A reaction between Pd(OAc)2 and 2 in equimolar ratio in dichloromethane gave [(κ3‐N∩N∩N)Pd(η1‐OAc)] (4) which on further treatment with triflic acid in acetonitrile produced the [(κ3‐N∩N∩N)Pd(N≡C−CH3)]OTf (5). The complex 5 was further treated with auxiliary ligands to produce the cationic heteroleptic palladium complexes, [(κ3‐N∩N∩N)Pd(NC5H5)]OTf (6), [(κ3‐N∩N∩N)Pd(NC5H4CN)]OTf (7), and [(κ3‐N∩N∩N)Pd(NC5H4NMe2)]OTf (8), respectively. The newly synthesized compounds were characterized by 1H and 13C{1H} NMR spectroscopic techniques and the molecular structures of 2–4, 6 and 8 were established. The catalytic activity of palladium(II) complexes (3–8) were evaluated for the acylative Suzuki coupling reaction between aryl carboxylic acids and arylboronic acids to yield unsymmetrically substituted biaryl ketones. The effect of reaction conditions viz., solvent, base, temperature, catalyst loading were evaluated, and complex 4 was found to be an excellent catalyst with a maximum TOF of 19.8 min−1.