Depth and Stanley Depth of Multigraded Modules

We study the behavior of depth and Stanley depth along short exact sequences of multigraded modules and under reduction modulo an element.     

The equilibrium and kinetics of intermolecular hydrogen bonding in nitroarene anion radical–alcohol system: 1,3‐dinitro‐benzene anion radical – R–OH (R═CH3–, C2H5–, (CH3)2 CH–)

To explore the possibility of hydrogen bonding of a stable anion radical with DNA – component sugar, hormones, steroid, and so on (through hydroxyl group), as a first step, the possibility of hydrogen bonding of 1,3‐dinitrobenzene anion radical (1,3‐DNB^??) with aliphatic alcohols was studied. It was found that 1,3‐DNB^?? anion radical undergoes hydrogen bonding with alcohols: methanol, ethanol, and 2‐proponal. The hydrogen‐bonding equilibrium constant K_eq and the (hydrogen‐bonding) rate constants k₂ were evaluated through the use of linear scan and cyclic voltammetry theory and techniques. The K_eq was found to be in the range of 1.4–6.0 m ^?1, whereas the rate constants k₂ were found to be in the range of 1.5–3.6 m ^?1 s^?1, depending upon the hydrogen‐bonding agent and the equation used for the calculation of the rate constants. The hydrogen‐bonding number n was found to be around 0.5 or 1.0. The implication of this study in, for example, the replication of DNA, the prevention of the formation of super oxide, and so on is discussed. Copyright © 2012 John Wiley & Sons, Ltd.     

Stanley decompositions in localized polynomial rings

We introduce the concept of Stanley decompositions in the localized polynomial ring S _f where f is a product of variables, and we show that the Stanley depth does not decrease upon localization. Furthermore it is shown that for monomial ideals ${J \subset I \subset S_f}$ the number of maximal Stanley spaces in a Stanley decomposition of I/J is an invariant of I/J. For the proof of this result we introduce Hilbert series for ${\mathbb{Z}^n}$ -graded K-vector spaces.     

Continuous Flow Organic Synthesis under High‐Temperature/Pressure Conditions

Microreactor technology and continuous flow processing in general are key features in making organic synthesis both more economical and environmentally friendly. When preformed under a high‐temperature/pressure process intensification regime many transformations originally not considered suitable for flow synthesis owing to long reaction times can be converted into high‐speed flow chemistry protocols that can operate at production‐scale quantities. This Focus Review summarizes the state of the art in high‐temperature/pressure microreactor technology and provides a survey of successful applications of this technique from the recent synthetic organic chemistry literature.     

Saponins: the phytochemical with an emerging potential for curing clinical depression

Depression is on the rise globally and expected to lead in global burden of diseases by 2030. The current therapy has serious limitations in terms of safety, efficacy, tolerability and therapeutic success. This review, based on the literature of the last decade, is aimed at exploring the preclinical profile of plant-based saponins (the abundant secondary metabolite) as an emerging therapy for depression. Enough scientific evidences reflect that saponins promote neurogenesis, restore monoaminergic tone and enhance neurotrophic factors. In multiple stress models, they have exhibited adaptogenic effects via normalising hypothalamus–pituitary–adrenal axis, corticosterone levels and oxidative stress. Scientific data revealed neuroprotective effect of saponins by inhibiting apoptosis and intraneuronal calcium dynamics. Many plants possessing saponins as their principal antidepressant moiety need investigation at clinical level. Last decade literature revealed numerous preclinical reports supporting the role of saponins as natural cure for depression and justified their inclusion in antidepressant drug discovery programs.     

The nuclear magnetic resonance relaxation data analysis in solids: general R1/R1(ρ) equations and the model-free approach

The advantage of the solid state NMR for studying molecular dynamics is the capability to study slow motions without limitations: in the liquid state, if orienting media are not used, all anisotropic magnetic interactions are averaged out by fast overall Brownian tumbling of a molecule and thus investigation of slow internal conformational motions (e.g., of proteins) in solution can be conducted using only isotropic interactions. One of the main tools for obtaining amplitudes and correlation times of molecular motions in the μs time scale is measuring relaxation rate R(1)(ρ). Yet, there have been a couple of unresolved problems in the quantitative analysis of the relaxation rates. First, when the resonance offset of the spin-lock pulse is used, the spin-lock field can be oriented under an arbitrary angle in respect to B(0). Second, the spin-lock frequency can be comparable or even less than the magic angle spinning rate. Up to now, there have been no equations for R(1)(ρ) that would be applicable for any values of the spin-lock frequency, magic angle spinning rate and resonance offset of the spin-lock pulse. In this work such equations were derived for two most important relaxation mechanisms: heteronuclear dipolar coupling and chemical shift anisotropy. The validity of the equations was checked by numerical simulation of the R(1)(ρ) experiment using SPINEVOLUTION program. In addition to that, the applicability of the well-known model-free approach to the solid state NMR relaxation data analysis was considered. For the wobbling in a cone at 30° and 90° cone angles and two-site jump models, it has been demonstrated that the auto-correlation functions G(0)(t), G(1)(t), G(2)(t), corresponding to different spherical harmonics, for isotropic samples (powders, polycrystals, etc.) are practically the same regardless of the correlation time of motion. This means that the model-free approach which is widely used in liquids can be equally applied, at least assuming these two motional models, to the analysis of the solid state NMR relaxation data.     

Expanding the Frequency Range of the Solid-State T1 ρ Experiment for Heteronuclear Dipolar Relaxation

Solid-state spin–lattice relaxation in the rotating frame permits the investigation of dynamic processes with correlation times in the range of microseconds. The relaxation process in organic solids is driven by the fluctuation of the local magnetic field due to the dipole–dipole interaction of the probe nuclei (¹³C,¹⁵N) with ¹H in close proximity. However, its effect is often hidden by a competing relaxation process due to the contact between the rotating frame ¹³C/¹⁵N Zeeman and ¹H dipolar reservoirs. In most cases the latter process becomes superior for the commonly applied low and moderate spin-lock fields and practically does not provide information about the molecular dynamics. To suppress this undesired process and to expand the dynamic range of T_{1 ρ} experiments, we present two approaches. The first one uses a resonance offset of the frequency of the spin-lock irradiation, which leads to a significant enhancement of the effective spin-lock frequency without the application of destructive high transmitter powers. We derive the theory and demonstrate the applicability of the method on various model compounds. The second approach utilizes heteronuclear ¹H decoupling during the ¹³C/¹⁵N spin-lock irradiation which disrupts the contact between the ¹³C/¹⁵N Zeeman and ¹H dipolar reservoirs. We demonstrate the method and discuss the results qualitatively.     

Mean-field expansion and meson effects in chiral condensate of analytically regularized Nambu-Jona-Lasinio model

Scalar meson contributions in chiral quark condensate are calculated in the analytically regularized Nambu-Jona-Lasinio model using the framework of mean-field expansion in bilocal-source formalism. The sigma-meson contribution for physical values of the parameters is found to be small. Pion contribution is found to be significant and should be taken into account for the choice of the parameter values.     

Sol–gel synthesis,characterization and water vapor adsorption properties of 1,1′-(1,6-hexanediyl)-bis(imidazolium)dichloride-silica hybrid material

1,1′-(1,6-hexanediyl)-bis(imidazolium)dichloride-silica hybrid material was prepared in 90 % yield by ammonia catalyzed sol–gel condensation of 1,1′-(1,6-hexanediyl)-bis[3-(3-triethoxysilylpropyl)-imidazolium]dichloride in aqueous ethanol. This novel ionic liquid-silica hybrid material can adsorp 27 % w/w water vapor in 90 min at room temperature and atmospheric pressure. This is a higher water adsorption capacity and rate than commercial desiccant Drierite which showed only 16 % w/w of water vapor adsorption and required 10 h to reach the maximum adsorption under identical conditions. The new adsorbent could be reused for five cycles without any significant loss in activity after regeneration by heating at 110 °C, for 24 h.     

Synthesis,Characterization, and Silver Nanoparticles Fabrication in N-isopropylacrylamide-Based Polymer Microgels for Rapid Degradation of p-Nitrophenol

Multiresponsive poly(N-isopropylacrylamide-co-methacrylic acid) microgels were synthesized by precipitation polymerization in aqueous medium. Then silver-poly(N-isopropylacrylamide-co-methacrylic acid) hybrid microgels were prepared by in-situ reduction of silver ions. Formation of microgels was confirmed by Fourier transform infrared spectroscopic analysis. pH and temperature sensitivity of microgel was studied by dynamic light scattering. Hydrodynamic radius of microgels decreases with increase in temperature at pH 8.20 and show volume phase transition temperature around 45°C. At pH 2.65, hydrodynamic radius decreases with increase in temperatures upto 35°C but further increase in temperature causes aggregation and microgel becomes unstable due to increase of hydrophobicity. With increase in pH of medium, the hydrodynamic radius of microgels increases sigmoidally. Formation of silver nanoparticles inside microgel and pH dependence of surface plasmon resonance wavelength of the hybrid microgels were investigated by ultraviolet-visible spectroscopy. The value of surface plasmon resonance band and absorbance associated with surface plasmon resonance band increases with increases in pH of the medium. The apparent rate constant of reduction of p-nitrophenol was found to be linearly dependent on volume of hybrid microgels used as catalyst. The system has a potential to be used as effective catalyst for rapid degradation of industrial pollutant.