Electron momentum density and band structure calculations of α- and β-GeTe

We have measured isotropic experimental Compton profile of α-GeTe by employing high energy (662 keV) γ-radiation from a ¹³⁷Cs isotope. To compare our experiment, we have also computed energy bands, density of states, electron momentum densities and Compton profiles of α- and β-phases of GeTe using the linear combination of atomic orbitals method. The electron momentum density is found to play a major role in understanding the topology of bands in the vicinity of the Fermi level. It is seen that the density functional theory (DFT) with generalised gradient approximation is relatively in better agreement with the experiment than the local density approximation and hybrid Hartree–Fock/DFT.     

Maximizing the Potency of siRNA Lipid Nanoparticles for Hepatic Gene Silencing In Vivo

Special (lipid) delivery: The role of the ionizable lipid pK(a) in the in?vivo delivery of siRNA by lipid nanoparticles has been studied with a large number of head group modifications to the lipids. A tight correlation between the lipid pK(a) value and silencing of the mouse FVII gene (FVII ED(50) ) was found, with an optimal pK(a) range of 6.2-6.5. The most potent cationic lipid from this study has ED(50) levels around 0.005?mg?kg(-1) in mice and less than 0.03?mg?kg(-1) in non-human primates.     

Effect of processing routes on microstructure, electrical and dielectric behavior of Mg-doped CaCu3Ti4O12 electro-ceramic

In the present communication, data on magnesium-doped calcium copper titanate CaCu_2.90Mg_0.10Ti₄O₁₂ (CCMTO) electro-ceramic, synthesized by the semi-wet route (SWR), ball-milled route (BMR) and solid-state route (SSR), is characterized by TG-DTA, XRD, SEM, EDX and TEM techniques. XRD confirmed the formation of single phase in CCMTO ceramic. The CuO phase present at grain boundaries in SWR ceramic was shown by the SEM micrograph, which was verified by EDX. The TEM image of SWR ceramic shows nanocrystalline particles in the range 80±20 nm. The value of the dielectric constant of SWR (ε _r ～20091) ceramic is higher than those of BMR and SSR (ε _r ～1247) ceramics at 1 kHz at 450 K. A dielectric relaxation has been observed in the frequency range 100 Hz–100 kHz. The high-temperature dielectric dispersion shows one large low-frequency response and two Debye-type relaxations. The impedance and modulus studies show the highest grain-boundary resistance for BMR ceramic.     

Synthesis,biological evaluation,and molecular docking study of pyridine clubbed 1,3,4-oxadiazoles as potential antituberculars

A series of pyridine clubbed 1,3,4-oxadiazole derivatives were efficiently synthesized, characterized by standard spectral techniques and evaluated for their in vitro antitubercular activity against Mycobacterium tuberculosis (MTB) H₃₇Ra and Mycobacterium bovis BCG in active and dormant state using an established methods. Compounds 5a, 5m, and 5t were identified as the most active compounds against MTB. Molecular docking was performed against MTB enoyl-ACP (CoA) reductase (FabI/ENR/InhA) enzyme to predict the binding modes and affinity. The theoretical predictions from molecular docking could establish a link between the observed biological activity and the binding affinity shedding light into specific bonded and non-bonded interactions influencing the activity. The active compounds were studied for cytotoxicity against three cell lines and were found to be non-cytotoxic. Specificity of these compounds was checked by screening them for their antibacterial activity against four bacterial strains.     

Synthesis and biological evaluation of new 2-aryl-4-((4-aryl-1H-1,2,3-triazol-1-yl)methyl)thiazole derivatives

Research on Chemical Intermediates - A series of 2-aryl-4-((4-aryl-1H-1,2,3-triazol-1-yl)methyl)thiazole derivatives (8a–p) have been synthesized. The structure of the newly synthesized...     

Voltammetric determination of molybdenum in brines

Summary The presence of molybdenum in natural water, at the ng/ml level, is essential for the growth of phytoplankton and other organisms, but its presence in brines is reported to affect the current efficiency in electrochemical chlor-alkali production. A voltammetric method, incorporating a preconcentration step, has been developed for the determination of molybdenum at this level in brine and sea-water. Molybdenum is co-precipitated with cadmium sulphide at a pH of about 2. The precipitate is dissolved in aqua regia and fumed with perchloric acid. The residue is dissolved in a supporting electrolyte comprising 1M sodium perchlorate, 0.1M sodium acetate and 0.01M EDTA (pH 6.0±0.2). At this pH, a well-defined wave for the reduction of molybdenum(VI) is obtained at –0.88 Vvs. SCE. None of the common ions interferes. Preconcentration of the molybdenum from 1 litre of brine facilitates its determination down to 1 ng/ml. The estimated precision at the 5 ng/ml level is 13%.

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Voltammetrische Molybdänbestimmung in Salzwasser

Zusammenfassung Die Anwesenheit von Molybdän in natürlichem Wasser in der Größenordnung von ng/ml ist für das Wachstum von Phytoplankton und anderen Organismen wesentlich, aber, wie berichtet wird, stört seine Anwesenheit in Salzwässern die elektrochemische Produktion von Chlor bzw. Alkali. Eine voltammetrische Methode mit vorangehender Anreicherung wurde für die Molybdänbestimmung in dieser Größenordnung in Salz- und Meerwasser ausgearbeitet. Molybdän wird bei pH etwa 2 mit Cadmiumsulfid mitgefällt. Dieser Niederschlag wird in Königswasser gelöst und mit Perchlorsäure abgeraucht. Der Rückstand wird in einem Trägerelektrolyt mit 1M Natriumperchlorat, 0,1M Natriumacetat und 0,01M ÄDTA (pH 6,0±0,2) gelöst. Bei diesem pH erhält man bei –0,88 V gegen eine ges. Kalomelelektrode für die Reduktion von Mo(VI) eine wohldefinierte Welle. Keines der üblichen Ionen stört. Die Anreicherung des Molybdäns aus 1 Liter Salzwasser erleichtert seine Bestimmung bis zu 1 ng/ml. Die geschätzte Genauigkeit für die Größenordnung 5 ng/ml beträgt 13%.

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Presented at the 8th International Microchemical Symposium, Graz, August 28, 1980.     

Monitoring Cardiac Biomarkers with Aptamer-Based Molecular Pendulum Sensors

Reagent-free electronic biosensors capable of analyzing disease markers directly in unprocessed body fluids will enable the development of simple & affordable devices for personalized healthcare monitoring. Here we report a powerful and versatile nucleic acid-based reagent-free electronic sensing system. The signal transduction is based on the kinetics of an electrode-tethered molecular pendulum—a rigid double stranded DNA with one of the strands displaying an analyte-binding aptamer and the other featuring a redox probe—that exhibits field-induced transport modulated by receptor occupancy. Using chronoamperometry, which enables the sensor to circumvent the conventional Debye length limitation, the binding of an analyte can be monitored as these species increase the hydrodynamic drag. The sensing platform demonstrates a low femtomolar quantification limit and minimal cross-reactivity in analyzing cardiac biomarkers in whole blood collected from patients with chronic heart failure.     

Chiral Amine Catalyzed Reductive Aldol/Reductive Michael Addition Cascade Towards Enantioselective Synthesis of Benzannulated Diquinanes

Disclosed here an amine-catalyzed reductive aldol-condensation followed by an intramolecular reductive Michael-addition cascade employing Hantzsch ester as hydride source to a keto-bis-enone to provide enantio- and diastereoselective benzannulated diquinanes having three consecutive stereocenters, one of which is an all-carbon quaternary formyl stereocenter. Interestingly, on changing a tether connecting the ketone and an enone moiety from an aliphatic to an aromatic, a change in reactivity is observed. In this case, instead of the above-mentioned reductive aldol condensation, an asymmetric aldol reaction occurs, followed by an iminium/enamine isomerization and, finally diastereoselective Michael addition reaction occurs. As a result, a bis-benzannulated diquinane is obtained with vicinal congested quaternary chiral centers.     

Saturation Recovery EPR Spin-Labeling Method for Quantification of Lipids in Biological Membrane Domains

The presence of integral membrane proteins induces the formation of distinct domains in the lipid bilayer portion of biological membranes. Qualitative application of both continuous wave (CW) and saturation recovery (SR) electron paramagnetic resonance (EPR) spin-labeling methods allowed discrimination of the bulk, boundary, and trapped lipid domains. A recently developed method, which is based on the CW EPR spectra of phospholipid (PL) and cholesterol (Chol) analog spin labels, allows evaluation of the relative amount of PLs (% of total PLs) in the boundary plus trapped lipid domain and the relative amount of Chol (% of total Chol) in the trapped lipid domain (Raguz et al. Exp Eye Res 140:179–186, 24). Here, a new method is presented that, based on SR EPR spin-labeling, allows quantitative evaluation of the relative amounts of PLs and Chol in the trapped lipid domain of intact membranes. This new method complements the existing one, allowing acquisition of more detailed information about the distribution of lipids between domains in intact membranes. The methodological transition of the SR EPR spin-labeling approach from qualitative to quantitative is demonstrated. The abilities of this method are illustrated for intact cortical and nuclear fiber cell plasma membranes from porcine eye lenses. Statistical analysis (Student’s t test) of the data allowed determination of the separations of mean values above which differences can be treated as statistically significant (P ≤ 0.05) and can be attributed to sources other than preparation/technique.