Many-body interaction in glycine-(water)3 complex using density functional theory method

Various configurations were investigated to find the most stable structures of glycine-(water)3 complex. Five different optimized conformers of glycine-(water)3 complex are obtained from density functional theory calculations using 6-311++G* basis set. Relaxation energy and many body interaction energies (two, three, and four body) are also calculated for these conformers. Out of the five conformers, the most stable conformer has the BSSE corrected total energy -513.917 967 7 Hartree and binding energy -27.28 Kcal/mol. It has been found that the relaxation energies, two body energies and three body energies have significant contribution to the total binding energy whereas four body energies are very small. The chemical hardness and chemical potential also confirmed the stability of the conformer having lowest total energy.     

Effect of electrode membrane surface ratio and thickness on lead electrode potential

Summary The lead ion selective electrode (ISE) consisting of PbS-Ag₂S is normally used with a membrane surface of outer layer areaA _o) and inner layer area (A _i) at unity (A _o=A _i). Partial covering of one surface area with an insulating material and keeping the other surface layer intact resulted in different ratios of membrane surface areas exposed to lead solutions. The potential linearly increased with increasing theA _o/A _i ratio and decreased with decreasing theA _o/A _i ratio. The lead ISE potential increased linearly with increasing the membrane thickness, but which required much longer time for a stable potential.

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Wirkung von Oberflächenverhältnis und Dicke der Elektrodenmembran auf das Potential einer Bleielektrode

Zusammenfassung Die aus PbS-Ag₂S bestehende spezifische Bleiionen-Elektrode wird üblicherweise mit einem Oberflächenverhältnis der Außenfläche (A _o) und der Innenfläche (A _i) mitA _o=A _i verwendet. Durch teilweise Abdeckung einer Oberfläche mit isolierendem Material, ohne daß die andere Oberfläche verändert wird, ergaben sich verschiedene Verhältnisse der mit der Bleilösung in Berührung stehenden Oberflächen. Mit dem VerhältnisA _o/A _i stieg das Potential linear an bzw. es fiel mit diesem Verhältnis ab. Das Potential der spezifischen Bleielektrode stieg mit der Dicke der Membran, stabilisierte sich aber wesentlich langsamer.

     

Effect of gamma/neutron irradiation and permanganate additives on thermal decomposition of ammonium perchlorate

When mixed with 2% by weight of either KMnO₄, Ba(MnO₄)₂ or NH₄MnO₄, an enhanced thermal decomposition of cubic ammonium perchlorate, AP, was observed over the temperature range 255–300?. A still more pronounced effect was observed when AP was subjected to a radiation dose of 10 Mrad. The activation energy involved over the acceleratory stage was found to be 46 kJ mol^?1 for the irradiated AP, as against the normal value of 85 kJ mol^?1. The value remained unaltered in the case of the first two additives, while in the presence of NH₄MnO₄ it decreased to 55 kJ mol^?1. Neutron bombardment did not change the decomposition characteristics of AP; the³⁸Cl activity produced following the (n, γ) reaction showed highly damaged centres with the activity distribution ratio 0∶8.5∶20∶71.5 for ClO ₄ ^? ∶ ClO ₃ ^? ∶ (ClO^? + ClO ₂ ^? ) ∶ Cl^?. Heating above 220? created further disorder through complete reduction of the recoil oxyanions.     

Radioactive tracer study of adsorption and exchange reaction of lead ion selective electrode membrane

Summary The amount of adsorption and exchange of lead on the electrode membrane as a function of time was correlated to the potential measurement stability. The adsorption and exchange of lead in various organic solvents tend to be increased relating to the increase in the dielectric constant of solvents. Removal of O₂ and CO₂ and addition of methanol and formaldehyde are very effective means to improve the potential stability. The behavior of lead ISE exposed to solutions containing lead and other interfering ions was also studied.

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Radiochemische Untersuchung der Adsorptions- und Austauschreaktionen bleiionenspezifischer Elektroden

Zusammenfassung Adsorption und Austausch von Blei an der Elektrodenmembran als Funktion der Zeit wurden zur Stabilität der Potentialmessung in Beziehung gesetzt. In verschiedenen organischen Lösungsmitteln steigen Adsorption und Austausch mit der Dielektrizitätskonstante an. Die Entfernung von O₂ und CO₂ sowie der Zusatz von Methanol und Formaldehyd verbessern die Stabilität des Potentials. Das Verhalten von bleiionenspezifischen Elektroden gegenüber Lösungen, die Blei und andere störende Ionen enthalten, wurde untersucht.

     

Kinetics of ethynylation of formaldehyde to butynediol

Activity of Cu catalysts and kinetics of ethynylation of formaldehyde using Cu₂C₂ catalyst has been studied. The reaction was found to be 0.41 and 0.58 order with respect to acetylene and formaldehyde concentrations, respectively. The activation energy of the reaction was found to be 15.13 kcal/mol.

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Cu₂C₂ . 0,41 0,58 . 15,13 /.

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NCL Communication No.: 3095     

A novel system for the synthesis of nitriles from aldehydes using aqueous ammonia and sodium dichloroiodate

A simple and mild method for the conversion of varieties of aldehydes to the corresponding nitriles using aqueous ammonia and aqueous sodium dichloroiodate reagent at room temperature is discussed. Advantages of this system are short reaction time, easy work-up and moderate to good yields.     

Higher hydrogen uptake capacity of C2H4Ti+ than C2H4Ti: a quantum chemical study

Using density functionals theory, we show that gravimetric hydrogen uptake of C₂H₄Ti complex and its cation, C₂H₄Ti⁺, differ by about 2 wt%. Six and five hydrogen molecules are found to be adsorbed on C₂H₄Ti⁺ and C₂H₄Ti complexes thereby showing a hydrogen-uptake capacity of 13.74 and 11.72 wt%, respectively. All hydrogen molecules are adsorbed in molecular form on C₂H₄Ti⁺ ion with an increase in metal bond strength, whereas in some cases, the hydrogen molecules are found to be dissociated on C₂H₄Ti neutral complex. The uptake capacity of neutral C₂H₄Ti complex shown in this work is in excellent agreement with that reported experimentally, Phillips and Shivaram (Phys Rev Lett 100:105505, 2008). The H₂ adsorption energy and its dependence on exchange and correlation functions in density functionals method were illustrated. Even after the adsorption of maximum number of hydrogen molecules on C₂H₄Ti and C₂H₄Ti⁺ complexes, Ti and Ti⁺ remain strongly bound to C₂H₄ substrate.     

Directed evolution of cyclic peptides for inhibition of autophagy

In recent decades it has become increasingly clear that induction of autophagy plays an important role in the development of treatment resistance and dormancy in many cancer types. Unfortunately, chloroquine (CQ) and hydroxychloroquine (HCQ), two autophagy inhibitors in clinical trials, suffer from poor pharmacokinetics and high toxicity at therapeutic dosages. This has prompted intense interest in the development of targeted autophagy inhibitors to re-sensitize disease to treatment with minimal impact on normal tissue. We utilized Scanning Unnatural Protease Resistant (SUPR) mRNA display to develop macrocyclic peptides targeting the autophagy protein LC3. The resulting peptides bound LC3A and LC3B—two essential components of the autophagosome maturation machinery—with mid-nanomolar affinities and disrupted protein–protein interactions (PPIs) between LC3 and its binding partners in vitro. The most promising LC3-binding SUPR peptide accessed the cytosol at low micromolar concentrations as measured by chloroalkane penetration assay (CAPA) and inhibited starvation-mediated GFP-LC3 puncta formation in a concentration-dependent manner. LC3-binding SUPR peptides re-sensitized platinum-resistant ovarian cancer cells to cisplatin treatment and triggered accumulation of the adapter protein p62 suggesting decreased autophagic flux through successful disruption of LC3 PPIs in cell culture. In mouse models of metastatic ovarian cancer, treatment with LC3-binding SUPR peptides and carboplatin resulted in almost complete inhibition of tumor growth after four weeks of treatment. These results indicate that SUPR peptide mRNA display can be used to develop cell-penetrating macrocyclic peptides that target and disrupt the autophagic machinery in vitro and in vivo.

SUPR peptide mRNA display was used to evolve a cell-permeable, macrocyclic peptide for autophagy inhibition.     

Temperature dependent energy-dispersive X-ray diffraction and magnetic study of Fe/Al interface

In situ temperature dependent energy-dispersive structural and magnetic study of electron beam evaporated Fe/Al multilayer sample (MLS) has been investigated. The structural studies show the formation of an intermixed FeAl transition layer of a few nanometers thick at the interface during deposition, which on annealing at 300 °C transforms to B2FeAl intermetallic phase. Magnetization decreases with increase in temperature and drops to minimum above 300 °C due to increase in anti-ferromagnetic interlayer coupling and formation of nonmagnetic FeAl phase at the interface. The Curie temperature (T_c) is found to be 288 °C and is much less than that of bulk bcc Fe.     

Maghemite (hematite) core (shell) nanorods via thermolysis of a molecular solid of Fe-complex

An Fe-metal complex with 2'-hydroxy chalcone (2'-HC) ligands [Fe(III) (2'-hydroxy chalcone)(3)] is synthesized by a chemical route and is subjected to different thermal treatments. Upon thermolysis in air at 450 °C for 3 h the complex yields maghemite (γ-Fe(2)O(3)) nanorods with a thin hematite (α-Fe(2)O(3)) shell. X-Ray diffraction (XRD), M?ssbauer spectroscopy, diffuse reflectance spectroscopy (UV-DRS), high resolution transmission electron microscopy (HR-TEM), field emission scanning electron microscopy (FE-SEM) and vibrating sample magnetometry (VSM) are used to characterize the samples. The stability of the ligand and the Fe-complex is further examined by using thermogravimmetric/differential thermal analysis (TGA/DTA). We suggest a residual ligand controlled mechanism for the formation of an anisotropic nanostructure in a crumbling molecular solid undergoing ligand decomposition. Since the band gap of iron oxide is in the visible range, we explored the use of our core shell nano-rod sample for photocatalytic activity for H(2) generation by H(2)S splitting under solar light. We observed high photocatalytic activity for hydrogen generation (75 ml h(-1)).