Divalent nitrogen-rich cationic salts with great gas production capacities

Monocyclic nitrogen-rich 3-(aminomethyl)-4,5-diamine-1,2,4-triazole(1)and fused cyclic 3,7-diamine-6-(aminomethyl)-[1,2,4]triazolo[4,3-b][1,2,4]triazole(9)were synthesized through the convenient cyclization reaction from the readily available reactant.Their energetic salts with high nitrogen content were proved to be rare examples of divalent monocyclic/fused cyclic cationic salts according to the single crystal analyses.The structure of intermediate B was also identified and verified by its trivalent cation crystal 17.5H_2O indirectly.Energetic compounds 2-8 and 10-17 were fully characterized by NMR spectroscopy,infrared spectroscopy,differential scanning calorimetry,elemental analysis.These energetic salts exhibit good thermal stability with decomposition temperatures ranged from 182℃to 245℃.The sensitivity of compounds 2,6,10 and 14 is similar or superior to that of RDX while the others were much more insensitive to mechanical stimulate.Furthermore,detonation velocity of 10(8843 m/s)surpass that of RDX(D=8795 m/s).Considering the high gas production volume(≥808 L/kg)of 2,4,10and 12,constant-volume combustion experiments were conduct to evaluate their gas production capacities specifically.These compounds possess much higher maximum gas-production pressures(P_(max):7.88-10.08 MPa)than the commonly used reagent guanidine nitrate(GN:P_(max)=4.20 MPa),which indicate their strong gas production capacity.

A Theoretical Study of Tris-(o-benzoquinonediimine)-First-Row Divalent Transition Metal Complexes

The ligand o-phenylenediamine (opda) and its oxidized form, o-benzoquinonediimine (bqdi), act as a fascinating candidate coordinating toward transition metal ions leading to the photochemical hydrogen production in absence of photosensitizers. Herein, we report the systematic study of the interaction between the oxidized form bqdi ligand, tris-(o-benzoquinonediimine) with divalent first-row transition metal series using DFT calculations. The lowest energy structures, bond length, binding energies, frontier molecular orbital analysis, natural bond orbitals, and global reactivity descriptor were calculated using B3LYP/6-311G(d,P) level of theory. The time dependent-DFT at the CAM-B3LYP/6-311+G(d,p) level of theory was applied to determine the electronic structures and the optical spectra. The theoretical binding trend of the divalent first-row transition metal series is decreasing as follows: Cu >Ti > V > Co > Ni > Fe > Cr > Zn >Mn. Among them, the binding potency of iron (II) by the bqdi ligand was not predominantly sturdy as compared to other first-row divalent transition metal ions. The origin of strong coordination with Fe(II) is attributed to its extra capability to induce covalent coordination of bqdi ligands. The complex exhibited two strong peaks at 370 nm and 452 nm, due to the HOMO-3 to LUMO+1 and HOMO-1 to LUMO transitions, respectively. Natural bond orbital analysis showed that the major interaction happens between the N lone pair electrons of the ligand with an anti-bonding orbital of metal ions, in which Ti showed the highest interaction energy than other metal ions. The present systemic DFT study of bqdi ligands with the first-row transition metals strongly encourages the future establishment of photochemical hydrogen production in absence of photosensitizers.

Divalent metal transporter 1 expression and iron deposition in the substantia nigra of a rat model of Parkinson's disease

Extensive iron deposition has been observed in the midbrain substantia nigra （SN） of Parkinson＇s disease （PD） patients, but the mechanisms of iron deposition in the SN remain poorly understood. The present study investigated the relationship between dopaminergic neuronal damage, iron content changes, and divalent metal transporter 1 （DMT1） in the midbrain SN of PD rats to explore the relationship between time of iron deposition and DMT1 expression. Frozen midbrain SN sections from model rats were stained with Perls＇ iron. Results showed massive loss of tyrosine hydroxylase （TH）-positive cells in the SN and increased DMT1 expression in model group rats. No obvious iron deposition was observed in the SN during early stages after damage, but significant iron deposition was detected at 8 weeks post-injury. Results demonstrate that the loss of TH-positive cells in the SN appeared simultaneously with increased DMT1 expression. Extensive iron deposition occurred at 8 weeks post injury, which could be regarded as an early time window of iron deposition.

Synthesis and anti-shock activity of divalent β-D-galactopyranosyl-(1→4)-β-D-glucopyranosides

Three divalent β-D-galactopyranosyl-（1 → 4）-β-D-glucopyranosides were synthesized using acetylated lactosyl bromide as donor and polyethylene glycols with different polymeric degree （n = 4, 5, 6） as linker, and evaluated for in vivo inhibitory activity to leukocyte-endothelial cell adhesion on severe bum-shock rats. The result showed that the length of linkers had apparent influence on anti cell adhesion activity.

Up-regulation of divalent metal transporter 1 in 6-hydroxydopamine intoxication is IRE/IRP dependent

Iron plays a key role in Parkinson＇s disease （PD）. Increased iron content of the substantia nigra （SN） has been found in PD patients, and divalent metal transporter 1 （DMT1） has been shown to be up-regulated in the SN of both MPTP-induced PD models and PD patients. However, the mechanisms underlying DMT1 up-regulation are largely unknown. In the present study, we observed that in the SN of 6-hydroxydopamine （6-OHDA）-induced PD rats, DMT1 with the iron responsive element （IRE, DMTI＋IRE）, but not DMT1 without IRE （DMTI-IRE）, was up- regulated, suggesting that increased DMTI＋IRE expression might account for nigral iron accumulation in PD rats. This possibility was further assessed in an in vitro study using 6-OHDA-treated and DMTl＋IRE-over-expressing MES23.5 cells. In 6-OHDA-treated MES23.5 cells, increased iron regulatory protein （IRP） 1 and IRP2 expression was observed, while silencing of IRPs dramatically diminished 6-OHDA-indueed DMTI＋IRE up-regulation. Pre- treatment with N-acetyl-L-cysteine fully suppressed IRPs up-regulation by inhibition of 6-OHDA-indueed oxidative stress. Increased DMTI＋IRE expression resulted in increased iron influx by MES23.5 cells. Our data provide direct evidence that DMTI＋IRE up-regulation can account for IRE/IRP-dependent 6-OHDA-induced iron accumulation initiated by 6-OHDA-induced intracellular oxidative stress and that increased levels of intracellular iron result in ag- gravated oxidative stress. The results of this study provide novel evidence supporting the use of anti-oxidants in the treatment of PD, with the goal of inhibiting iron accumulation by regulation of DMT1 expression.

First-principles Study of Divalent ⅡA and Transition ⅡB Metals Doping into Cu_2O

Divalent IIA metals such as Be, Mg, Ca, Sr, Ba and transition IIB metals such as Zn, Cd were investigated as possible n-type dopants into the Cu2 O theoretically by using the first-principles calculations based on density functional theory. By systematical analyses of the lattice parameters, the bond length, the electronic structure, the local density of states and the defect formation energy for various doping systems, it is revealed that Ca, Sr, Ba and Be are more suited for n-type doping into Cu2O as shallow donors, compared to Mg which introduces a relatively deep donor level in Cu2O. Meanwhile, Zn and Cd can hardly be doped into Cu2O due to the positive formation energy of relevant defects.

Polymerization of Phenyl Isocyanate by Divalent Samarium Complex (ArO)_2Sm(THF)_4 (ArO=2,6-di-tert-butyl-4-methylphenoxo)

Phenyl isocyanate was for the first time successfully polymerized by divalent samarium complex (ArO)2Sm(THF)4. The monomer concentration and temperatur affected the polymerization greatly.

Changes in iron transporter divalent metal transporter 1 in proximal jejunum after gastric bypass

AIM: To describe the variation that divalent metal transporter 1 (DMT1) shows in patients after Roux-en-Y gastric bypass (RYGB) surgery.

Prediction of Enthalpies of Fusion for Divalent Rare Earth Halides Based on Modeling by Artificial Neural Networks and Pattern Recognition

The artificial neural network (ANN) and the pattern recognition were applied to study the correlation of enthalpies of fusion for divalent rare earth halides with their microstructural parameters,such as ionic radius and electronegativity. The model,represented by a back-propagation netal network, was trained with a 12 set of published data for divalent rare earth halides and then was used to predict the unknown ones. Also the criterion equations were ptesented to determine the enthalpies of fuSion for divalent rare earth halides using pattern recognition in mis work. The results from the model in ANN and criterion equations are in very good agreement with reference data.

The Effects of Zinc and Other Divalent Cations on M-Current in Ventral Tegmental Area Dopamine Neurons

Ventral tegmental area dopamine (DA VTA) neurons are important for the reinforcing effects of drugs of abuse such as ethanol and nicotine. We have previously shown that M-current (IM) regulates the excitability of DA VTA neurons. Zinc (Zn2+) contributes to the regulation of neuronal excitation as a neuromodulator. In the present study, we investigated zinc effect on the properties of IM and the spontaneous firing frequency of DA VTA neurons. The standard deactivation protocol was used to measure IM during voltage-clamp recording with a hyperpolarizing voltage step to ﹣40 mV from a holding potential (VH) of ﹣25 mV. Zn2+ (100 μM) inhibited IM amplitude and IM recovered completely from the inhibition after the washout of Zn2+. Zn2+ inhibited IM in a concentration-dependent manner (IC50: 5.8 μM). When hyperpolarizing voltage steps were given to ﹣65 mV (in 10 mV increments) from a VH of ﹣25 mV, Zn2+ (100 μM) reduced IM amplitude at each voltage and zinc inhibition of IM was not voltage-dependent. Zn2+ increased the spontaneous firing frequency of DA VTA neurons in a concentration-dependent manner, suggesting that Zn2+ causes excitation of DA VTA neurons through an action on IM. IM of DA VTA neurons was inhibited by 100 μM divalent cations in increasing order of potency: Ba2+ (16%) 2+ (25%) 2+ (40%) 2+ (59%) 2+ (67%). These results suggest that Zn2+ may exert physiologically significant regulation of neuronal excitability in DA VTA neurons.

SYBR Green I-based product-enhanced reverse transcriptase assay for quantification of retroviral PFV and detection of the divalent cation preference of PFV RT

Dear Editor,Prototype foamy virus(PFV)belongs to the genus Spumavirus in the Spumaretrovirinae subfamily of Retroviridae.Although PFV and HIV have much in common,research into PFV has lagged far behind that into HIV,as PFV appeared to be non-pathogenic both in accidentally infected humans and in experimentally infected animals.In recent decades,however,more attention has been focused on PFV because it seems to be

Implication of Electrostatic Forces on the Adsorption Capacity of a Modified Brick for the Removal of Divalent Cations from Water

Adsorption properties of brick for the removal of divalent cations increased significantly after this material were pre-activated by HCl and subsequently impregnated with ferrihydrite. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis demonstrated that ferrihydrite was preferentially attached to clays (mainly to metakaolinite) and possessed Na atoms at levels higher than those observed in iron-poor aggregates. Sodium is bound to hydroxyl groups which have a function as reactive sites and give rise to surface charge. Zeta potential measurements were conducted to determine the isoelectric point (IEP) and salt-addition method was used to assess the point of zero charge (PZC) of this brick. Modified brick has a positive charge in water up to pH ≈ 3.2 and negative charge above this pH. Moreover, pH was found to be the most important factor affecting the adsorption process, suggesting the possible implication of electrostatic forces at the brick-water interface. The complexation model proposed by James and Healy was applied to our system: theoretical data on free-energy changes due to effects associated both with electrostatic attraction and solvation, were found to be in agreement with those determined from kinetic experiments. Column experiments permitted further to show that adsorption reactions were strongly inhibited by addition of an inert electrolyte (like NaNO3). Under this condition, ionic strength increased and most surface sites of the brick would be occupied by Na+ ions, leading to a charge neutralization and thereby a depletion of electrostatic forces.

EFFECTS OF COMPOSITION AND STRUCTURE OF ALGTNATES ON ADSORPTION OF DIVALENT METALS

Results of a series of experiments(on the adsorption of divalent metal ions by dried alginic acid, Na and Ca alginates of different composition and block structure) conducted in this systematic study of the effects of the composition and structure of alginates on the static adsorption equilibrium of divalent metal ions indicate that the properties of alginate adsorption to divalent metal ions are highly different, depending not only on the cations used, but also on the form and structure of the alginates. There is close correlation between the adsorption properties and the structure of the alginates. The selectivity coefficient of Na alginate for Cd-Sr ion exchange tends to increase with the increase of the M/G ratio in alginate, whereas the adsorption capacity of Ca alginate for Cu2+ ion decrease with the increase of the G-block or the average length of the G-block (NG) and the total adsorption capacity of alginic acid is found to vary in the same order as the FMM(diad frequency) in alginate in the mixed solution of Sr2+, Ba2+ and Cd2+.

Synthesis of O-Glycosides of Heteroatom Aroyl-Substituted Heterocyclic Ketene Aminals

Heteroatom aroyl-substituted heterocyclic ketene aminals 1 reacted with 2,3,4,6-tetra-O-acetyl-α-glucopyranosyl bromide 2 under the catalysis of Hg(CN)2 or CaH2 to give E- or Z-O-glycosides of heterocyclic ketene aminals 3 or 4 in moderate yields.

Synthesis of Luminescent CdTe Nanorods on Anodized Aluminum Oxide Template and Their Utility in Divalent Heavy Metal Ion Sensing

A simple one-pot hydrothermal method to grow luminescent CdTe nanorods on porous anodized aluminum oxide (AAO) template is described. These CdTe nanorods on the AAO template were further applied as an optical probe to detect divalent heavy metal ions such as Hg, Pb, Mg and Zn, by examining its photoluminescence (PL) responses. The presence of Pb and Hg ions quenched the photoluminescence (PL) of the CdTe nanorods where as Zn and Mg ions enhanced it with the effect of red shift in the peak position respectively. These PL enhancements/quenching of the nanorods after exposing to the divalent ions were explained on the basis of the active surface related recombination, which depends on the direction of carrier transfer mechanism i.e. from nanorods to the surface adsorbed metal ions or vice-versa and is attributed to the alignment of bands thus formed. The luminescent CdTe nanorods grown on AAO template was found to be effective in sensing metal ions (Pb, Hg, Zn and Mg) up to a micro-molar concentration.

Syntheses of Divalent Rare Earth Ternary Halides KYbBr_(3), KYbCl_(3), KSm_(2)Br_(5), KSm_(2)C_(l5), KEu_(2)C_(l5) by Alkalimetallothermoreduction

Introduction CsEuF;, CsYbF;and RbYbF;are the first members of divalent rare earth ternary halides obtained via reduction of trivalent rare earth halides by alkali metals. Recently we adopted a new synthesis route in preparing divalent rare earth chlorides and bromides and the five titled compounds were suc-

Comparison of Enhancement Effect of DNA-Mediated Energy Transfer by Divalent Cations： Mg2＋, Ca2＋, Mn2＋, Co2＋, and Ni2＋

The effect of various metal ions on the DNA mediated energy transfer between simultaneously bound drugs was investigated using spectroscopic methods.It was found that addition of divalent metal ions(Mg^(2+),Ca^(2+),Mn^(2+),Co^(2+)and Ni^(2+))resulted in further decrease of the ethidium fluorescence intensity,while a small increase was observed in the TMPyP emission band,implying that the energy of excited ethidium was transferred to TMPyP.This DNA-mediated quenching efficiency between ethidium and TMPyP was significantly enhanced by the presence of all metal ions.Among the divalent metal ions,alkali earth metal ions and Mn^(2+)displayed higher quenching efficiencies than other transition metal ions.The distances required to permit the energy transfer between the two drugs in DNA were calculated as 68,66,62,48and 38in the presence of100μmol·L^(-1 )of Mg^(2+),Ca^(2+),Mn^(2+),Co^(2+)and Ni ^(2+)ion,respectively.The disturbed binding conformation of TMPyP in DNA by metal ions presumably accounts for the difference.

Experimental Design in Solvent Extraction: A Study for Divalent Metals Separation in D2EHPA/Isoparaffin System

The solvent extraction process combined with tools of experimental design assists in developing procedures for separation and purification of elements or mineral compounds with high purity. In this work the technique was used to replace the traditional methods for the collection of basic information required for the development of a circuit of solvent extraction. According to the literature, several factors may influence the extraction of divalent metals by D2EHPA in sulfate media, among which the concentration of metals in solution. The objective was to study the variables affecting the separation process Mn/Ni/Co/Cu, such as the aqueous/organic (A/O), contact time, concentrations of the divalent metals in sulfuric medium, pH and solvent concentration. An investigation into the variables that control the process was done using a “cube + star” experimental design, with central point. The results demonstrate it is possible to obtain of a satisfactory mathematical model that describes the process.

膜法分离一/二价阳离子的研究进展

各类工业过程如水质软化、食用盐纯化、盐湖卤水提锂、酸和重金属资源回收等对一/二价阳离子高效分离的需求日益增长,近年来,针对上述分离体系的膜材料的研究取得了诸多进展。本文详细总结了针对一/二价阳离子分离的选择性阳离子交换膜、纳滤膜、支撑液膜和离子印迹膜的研究进展,重点梳理了相关膜材料的离子选择性优化思路和机理,对比分析了上述膜过程的特点和适用场景。基于此,作者认为,离子筛分精细化是膜分离技术的重要发展方向。在分子尺度明晰分离层的形成和演化机理,对于提高界面聚合反应可控度,实现在亚纳米尺度膜结构的精细调控至关重要。通过在膜基体内可控构建目标离子的特异性识别位点和传质通道,有望实现高选择性离子筛分。此外,具有本征规则孔道结构的新型分离膜材料,如MOFs、COFs、二维层状结构膜等,在精细筛分方面具有良好的发展潜力。

基于阳离子调控的ADN防吸湿技术

二硝酰胺铵(ADN)作为一种极具应用前景的氧化剂,其阳离子NH4+易与空气中的水分子形成氢键,因而存在强吸湿性缺点,无法实现大规模化工程应用。据此,研究提出一种阳离子调控策略,结合Schiff base反应和离子交换反应,以对苯二甲醛(TPA)、氨基胍盐酸盐(AGC)和ADN为原料,通过操作简单、安全高效的一锅法反应,成功合成出含二价阳离子的新型二硝酰胺类含能离子盐(DBDN)。采用元素分析、红外光谱和核磁光谱等对其化学结构进行表征,同时结合热分析、机械感度测试和理论计算对其理化性能进行分析,并采用干燥器平衡法对ADN和DBDN进行吸湿性研究。结果显示,DBDN的撞击感度(IS)、摩擦感度(FS)和热分解温度(T_(d))分别为>40 J、16%和225℃,其安定性要远优于ADN(5 J、76%和198℃)。此外,在25℃、相对湿度(RH)分别为66%和75%的条件下,静置9 d后,ADN的吸湿率高达24.1%和39.5%,而DBDN仅为0.26%和0.48%,表现出不吸湿特性。