Aminosilane Functionalized Cenosphere in Poly(vinyl butyral) Composite Films: Moisture Resistant Encapsulated Schottky Devices

Functionalized cenosphere in PVB composite films were fabricated by melt processing. The composites show higher tensile strength with lower failure strain with increased filler ratio in the matrix. Fractographic images of the samples and DMA studies indicate brittle failure of the matrix. Moisture permeation and water contact angle studies reveal improved hydrophobicity of the matrix, while the factor of surface roughness increases the wettability at higher filler content. Schottky-structured devices encapsulated with functionalized cenosphere indicate enhanced resistance to moisture and increased life time for the devices.     

Influence of Ni ion site occupancy on laser induced third harmonic generation (THG) studies in Li2SO4–MgO–P2O5 amorphous system

Glasses of the composition Li₂SO₄–MgO–P₂O₅ mixed with varied contents (0.2–1.0 mol%) of nickel oxide were synthesized. Various spectroscopic investigations have indicated gradual growing proportions of O_h Ni²⁺ ions in the host glass. IR spectral results, in particular, have clearly demonstrated an increased degree of structural disorder of the glass nerwork with increased content of NiO. The intensity of third harmonic generation (THG) component of probing beam viz., Nd:YAG laser (λ = 1064 nm and power density J = 0–200 J/m²) induced due to the interaction of inherent dipoles with the incident laser beam, exhibited an increasing trend with increase of nickel oxide concentration up to 0.8 mol%. Analysis of the results of these studies indicated that Li₂SO₄–MgO–P₂O₅ glass samples doped with optimal content of NiO (~ 0.8 mol%) are more favorable for achieving intense THG beam with low phonon losses. Hence, such glasses may be considered as useful for optoelectronic devices. On the other hand, the samples doped with NiO content greater than 0.8 mol%, the Ni²⁺ ions seemed to prefer (revealed by optical absorption and IR spectroscopy studies) tetrahedral occupancy in the glass matrix and enhance the degree of the polymerization of the glass matrix; such increased order of polymerization of the glass matrix appears to be a hindrance for accomplishing higher intensity of THG signal due to large phonon losses. These results were found to be in concurrence with the inferences from other studies that include electrical properties, positron annihilation lifetime (PAL) spectroscopy and mechanical properties.     

Envisioning the composition effect on structural,magnetic, thermal and optical properties of mesoporous MgFe2O4-GO nanocomposites

The effect of variation in composition on the structural, magnetic, optical and photo catalytic activity of magnesium ferrite (MgFe₂O₄) -graphene oxide (GO) nanocomposites was studied. Magnetic nanocomposites of GO and MgFe₂O₄ nanoparticles (NPs) with varying w/w ratio were synthesized by facile sonication method. X-Ray diffraction patterns confirmed the presence of spinel ferrite phase in the nanocomposites with the crystalline size 8–32 nm. Fourier transformation infrared (FT-IR) spectra of the nanocomposites displayed absorption bands corresponding to GO and MgFe₂O₄ NPs along with red shift of bands corresponding to C=O, C=C and O-H stretching. Thermo gravimetric analysis confirmed higher stability of nanocomposites over pristine GO. Saturation magnetization increased from 3.63 to 11.10 emu/g with the increase in content of MgFe₂O₄ NPs in the nanocomposites. Scanning electron microscopy analysis along with energy dispersive spectroscopy (SEM-EDX) confirmed the presence of MgFe₂O₄ NPs along with GO sheets. Immobilization of clusters of MgFe₂O₄ NPs onto GO sheets was evident from transmission electron micrographs (TEM) of all the nanocomposites. BET surface area of the nanocomposites ranged from 63.04 to 165.29 m²/g and was maximum when GO:MgFe₂O₄ w/w ratio was 1:0.5. It was markedly higher than pristine GO and MgFe₂O₄ NPs. Optical studies revealed lowering of the band gap in the nanocomposites upto 2.21 eV as compared to pristine MgFe₂O₄ NPs. Photoluminescence (PL) spectra of nanocomposites displayed quenching of PL intensity with increase of GO content. Band gap also displayed similar trend. The synthesized nanocomposites were used as photocatalysts for methylene blue dye degradation under visible light irradiation. The nanocomposite with GO to MgFe₂O₄ ratio 1:0.5 displayed best activity with complete degradation of dye in 30 min. The results confirmed that the composition of GO based magnetic nanocomposites can be tailored for efficient removal of contaminants.     

Towards Understanding the Genetic Nature of Vasovagal Syncope

Syncope, defined as a transient loss of consciousness caused by transient global cerebral hypoperfusion, affects 30–40% of humans during their lifetime. Vasovagal syncope (VVS) is the most common cause of syncope, the etiology of which is still unclear. This review summarizes data on the genetics of VVS, describing the inheritance pattern of the disorder, candidate gene association studies and genome-wide studies. According to this evidence, VVS is a complex disorder, which can be caused by the interplay between genetic factors, whose contribution varies from monogenic Mendelian inheritance to polygenic inherited predisposition, and external factors affecting the monogenic (resulting in incomplete penetrance) and polygenic syncope types.     

Superparamagnetic nanocomposites derived from waste polyurethane foam for the removal of Rhodamine B: batch and continuous column studies

ABSTRACT

The present study is aimed at the utilization of waste polyurethane (PU) foam derived magnetized carbon material for the treatment of simulated dye effluent. Activated carbon (AC) was prepared from waste PU foam by chemical activation method using K₂CO₃. The surface of the prepared AC was incorporated with nano-sized iron oxide particles to aid the recovery of the spent adsorbent. The polyurethane derived AC-iron oxide (PUAC-Fe₃O₄) nanocomposites were characterized with FE-SEM, XRD, Vibrating Sample Magnetometer (VSM), FT-IR, TGA, surface area and point of zero charge. The morphology of the prepared AC had an extremely porous texture which was incorporated with iron oxide nanoparticles of size less than 100 nm with a surface area of 250 m²/g. The nanocomposites had superparamagnetic properties as evident from the VSM plot. The prepared PUAC-Fe₃O₄ nanocomposites was used for the removal of Rhodamine B (RB) dye. Batch adsorption studies were performed and the equilibrium parameters were calculated by fitting the data with Langmuir and Freundlich isotherm models. The thermodynamic parameters were also evaluated. The adsorption of RB dye onto PUAC-Fe₃O₄ composites was spontaneous and endothermic. Kinetic studies were also carried out and the data were tested with different kinetic models. Intraparticle diffusion model and Boyd plots suggested that the boundary layer diffusion step controlled the rate of adsorption. Continuous column studies were also performed and it proved that 1 g of prepared material was able to treat 1.075 L of 10 mg/L RB dye with an efficiency of 64.87%. The interferential effect of the electrolytes on the RB dye removal was also studied. Reusability studies proved that the prepared PUAC-Fe₃O₄ nanocomposites was efficient even after three cycles of operation.     

Studies on photo-crosslinkable polyphosphoramide esters containing divanillylidene cycloalkanone units

Two series of photo-crosslinkable polyphosphoramide esters were synthesized from 2,5-bis(4-hydroxy-3-methoxy benzylidene)cyclopentanone and 2,6-bis(4-hydroxy-3-methoxy benzylidene)cyclohexanone with various N-arylphosphoramide dichlorides by interfacial polycondensation using hexadecyl trimethylammonium bromide as phase transfer catalyst at ambient temperature. The resulting polymers were characterized by inherent viscosity, Fourier transform infra-red, ¹H and ¹³C nuclear magnetic resonance spectroscopy. The thermal stability of the polymers synthesized was evaluated by thermogravimetric analysis. These polymers were studied for their photo-chemical reactions. The divanillylidene cycloakanone groups in the polymer chain function as photo-active centres. Crosslinking proceeds via 2π + 2π cycloaddition reaction of the divanillylidene cycloalkanone moieties. The rate of crosslinking decreases with increase in the size of the cycloalkanone ring, while the thermal stability increases with increase in the size of the cycloalkanone ring.     

A Kinetic study of Tb3+ and Dy3+ co-substituted CoFe2O4 spinel ferrites using temperature dependent XRD,XPS and SQUID measurements

In this research work, we have investigated the structural development of Tb³⁺ and Dy³⁺ co-substituted CoFe₂O₄ ferrites using temperature and time dependent XRD measurements. Sol-gel auto combustion technique was used to synthesized Tb³⁺ and Dy³⁺ co-substituted spinel ferrites with composition CoFe_2-x-y Tb_xDy_yO₄ (x + y = 0.0–0.25). Various characterization techniques such as High temperature XRD, XPS and SQUID were used to observe the Kinetics mechanism as well as the impact of co-substitution on the structural and magnetic properties. Room temperature XRD scans showed that the synthesized materials having single phase and were crystalline in nature. The crystallite size was lied in nano regime ranging from 26.07 to 21.92 nm and lattice parameters were found to be decreased with increasing rare earth metal ions contents. Temperature and time dependent XRD data suggested that structure of investigated samples not degrade even at temperature 900 °C which was maintained for 2 h. The ionic states of Co²⁺, Tb³⁺, Dy³⁺ and Fe³⁺ were confirmed by X-ray Photoelectron spectrometry measurements along with the binding energies of Co2p, Tb 2p, Dy 2p, Fe 2p which confirmed the tetrahedral and octahedral sites for substituted ions. Room temperature magnetic measurements of annealed nanoferrites were carried out by operating the SQUID magnetometer in VSM mode. The data demonstrated that increasing concentrations of substituent (Tb³⁺and Dy³⁺) resulted in the reduction of various magnetic parameters such as remanence, saturation magnetization and Coercivity. The calculated values of saturation magnetization and coercivities were found in the range of 78.1–45.15emu/g and 742–543Oe respectively. This study concluded that cation distribution and crystallite size is effective in controlling the structural, morphological and magnetic properties.     

Recent advances in biomedical polyurethane biostability and biodegradation

This paper summarizes our recent efforts to better understand the effects of antioxidants, the effects of strain-state, mechanistic studies of soft segment cleavage by reactive oxygen radicals, and the effects of different soft segment chemistries on the biostability/biodegradation of polyether polyurethanes (PEUUs). In vivo cage implant system studies and in vitro cobalt ion/hydrogen peroxide studies have been carried out on PEUUs and the polymers have been analysed by attenuated total reflectance and Fourier transform infrared (ATR-FTIR) spectroscopy, and scanning electron microscopic (SEM) characterization of the PEUU surfaces. The natural antioxidant, vitamin E, has been shown to inhibit biodegradation and enhance biostability of PEUUs. Studies of the effect of stress state on PEUU biodegradation demonstrate that stress can inhibit biodegradation. While polyether soft segments may be cleaved by the presence of reactive oxygen radicals, the presence of oxygen has a profound effect in accelerating biodegradation. The biodegradation of polyurethanes may be inhibited by substituting different chemistries such as polydimethylsiloxanes, polycarbonates, and hydrocarbon soft segments for the polyether soft segments. To safely utilize polyurethanes in long-term biomedical devices, the biodegradation mechanisms of polyurethane elastomers must be fully understood and subsequently prevented. © 1998 SCI.     

Low‐lying energy isomers and global minima of aqueous nanoclusters: Structures and spectroscopic features of the pentagonal dodecahedron (H2O)20 and (H3O)+(H2O)20

We rely on a hierarchical approach to identify the low‐lying isomers and corresponding global minima of the pentagonal dodecahedron (H₂O)₂₀ and the H₃O⁺(H₂O)₂₀ nanoclusters. Initial screening of the isomers is performed using classical interaction potentials, namely the Transferable Interaction 4‐site Potential (TIP4P), the Thole‐Type Flexible Model, versions 2.0 (TTM2‐F) and 2.1 (TTM2.1‐F) for (H₂O)₂₀ and the Anisotropic Site Potential (ASP) for H₃O⁺(H₂O)₂₀. The nano‐networks obtained with those potentials were subsequently refined at the density functional theory (DFT) with the Becke‐3‐parameter Lee–Yang–Parr (B3LYP) functional and at the second order Møller–Plesset perturbation (MP2) levels of theory. For the pentagonal dodecahedron (H₂O)₂₀ it was found that DFT (B3LYP) and MP2 produced the same global minimum. However, this was not the case for the H₃O⁺(H₂O)₂₀ cluster, for which MP2 produced a different network for the global minimum when compared to DFT (B3LYP). The low‐lying networks of H₃O⁺(H₂O)₂₀ correspond to structures having 9 ‘free’ OH bonds and the hydronium ion on the surface of the nanocluster. The IR spectra of the various networks are further analysed in the OH stretching (‘fingerprint’) region and the various bands are assigned to structural arrangements of the underlying hydrogen bonding network. © 2012 Canadian Society for Chemical Engineering     

Transport of matter upon annealing in crystalline polymethylene systems: a calorimetric and spectroscopic study

Following Ungar and Keller we have shown that when a mechanical mixture of two solid and crystalline n-alkanes of slightly different length is annealed at temperatures below the melting point of the shorter compound a mixed crystal is obtained. Calorimetric and spectroscopic studies indicate that n-alkane chains of one molecular species are able to move out of the crystallite and diffuse into the crystal of the other species. A detailed mechanism on a molecular level consistent with calorimetric and spectroscopic experiments is proposed. Molecules migrate substantially as rigid bodies with no distinct sharp conformational distortions. The same phenomenon is observed for a mechanical mixture of C₃₆H₇₄ and for its perdeutero-derivative of the same length. The conclusions of Ungar and Keller are substantiated and new structural details are presented.     

Chitosan Microspheres as Carriers for pH‐Indicating Species in Corrosion Sensing

Chitosan microspheres containing bromocresol green, cresol red, and phenolphthalein for corrosion detection, through pH change, are synthesized in order to be used in protective coatings for aluminium alloys. Microspheres containing corrosion detection species are characterized morphologically (SEM) and physico‐chemically (FTIR, TGA). Release studies (UV–vis) are performed in corrosion‐promoting conditions (pH, NaCl), and detection studies by immersion in media associated with corrosion activity while microspheres' sensing activity is evaluated visually. Electrochemical characterization of AA2024 substrates in the presence of chitosan spheres is performed to understand material performance, and a color change is observed as a result of local pH increase in cathodic areas when corrosion takes place. These findings can be correlated with the results from release studies and seem a promising approach for corrosion sensing purposes, not only because pH increase is possible to detect due to corrosion, but also because chitosan is considered an environmentally friendly material.     

Methane coupling at low temperatures on Ru(0001) and Ru(11¯20) catalysts

The conversion of methane to higher hydrocarbons on single crystal Ru catalysts has been investigated using combined elevated-pressure kinetic measurements/surface science studies. The reaction consists of activation of methane on Ru(0001) and Ru(11¯20) surfaces to produce carbonaceous intermediates at temperatures between 350 and 700 K and rehydrogenation of these species to ethane and propane at 370 K. It is found that under the reaction conditions employed, the maximum yield in ethane/propane production occurs at 500 K on both surfaces. Influence of the hydrogenation temperature on the production of ethane and propane is also examined. On Ru(0001), the yields of ethane and propane maximize at = 400 K, whereas no maximum yield was observed on Ru(11 0) in the 300–500 K temperature range. Under optimum reaction conditions, hydrocarbon products consist of 16% ethane and 2% propane. High-resolution electron energy-loss spectroscopy (HREELS) has been used to identify various forms of hydrocarbonaceous intermediates following methane decomposition. An effort is made to relate the hydrocarbon intermediates identified by HREELS to the gas phase products observed in the elevated pressure experiments.     

Compaction of porous silica – A photophysical study

Photophysical studies, utilizing pyrene, are used to investigate the compaction of porous silica. Conventional studies show that the volume of this material is markedly reduced (4×) on compression to 1 G Pa. The nature of the processes giving rise to this volume change vary with the logarithm of the applied pressure. Organic molecules in particular pyrene, indicate that the surface of the silica wrinkles and provides new adsorption sites that screen the adsorbate from other molecules such a O₂, NH₃, and CCl₄. At high pressures a portion of the adsorbate is completely trapped in silica, if loaded onto the material prior to compaction. Adsorbates with weak bonds, e.g., bromopyrene are chemically altered on compaction in silica. The data amplify earlier studies on the uncompacted system, and confirm the heterogeneous environment of SiO₂ at the sites where organic molecules are adsorbed.     

Amikacin disulfate: an aminoglycoside antibiotic drug as a corrosion inhibitor for copper in 1 M nitric acid medium

The effect of commercially available pharmaceutically active compound amikacin disulfate (AMK) against the corrosion of copper in 1 M HNO₃ solution was investigated using Tafel polarization, electrochemical impedance spectroscopy (EIS), and weight loss techniques. The results show that inhibition efficiency (IE %) increases with increasing inhibitor concentration from 0.1 to 1.0 mM. Increasing the temperature increased the corrosion rate, and results decreased the inhibition efficiency. The adsorption of inhibitor obeyed Langmuir adsorption isotherm model via physisorption mechanism. EIS technique exhibits one capacitive loop, indicating that the corrosion reaction is controlled by charge transfer process. Polarization measurements showed that the AMK is mixed-type inhibitor. The surface morphologies were studied by scanning electron microscopy and atomic force microscopic techniques. The corrosion mechanism were explained by Fourier transform infrared spectroscopy.     

Structure–Activity Relationship of New Chimeric Analogs of Mastoparan from the Wasp Venom Paravespula lewisii

Mastoparan (MP) is an antimicrobial cationic tetradecapeptide with the primary structure INLKALAALAKKIL-NH₂. This amphiphilic α-helical peptide was originally isolated from the venom of the wasp Paravespula lewisii. MP shows a variety of biological activities, such as inhibition of the growth of Gram-positive and Gram-negative bacteria, as well as hemolytic activity and activation of mast cell degranulation. Although MP appears to be toxic, studies have shown that its analogs have a potential therapeutic application as antimicrobial, antiviral and antitumor agents. In the present study we have designed and synthesized several new chimeric mastoparan analogs composed of MP and other biologically active peptides such as galanin, RNA III inhibiting peptide (RIP) or carrying benzimidazole derivatives attached to the ε-amino side group of Lys residue. Next, we compared their antimicrobial activity against three reference bacterial strains and conformational changes induced by membrane-mimic environments using circular dichroism (CD) spectroscopy. A comparative analysis of the relationship between the activity of peptides and the structure, as well as the calculated physicochemical parameters was also carried out. As a result of our structure–activity study, we have found two analogs of MP, MP-RIP and RIP-MP, with interesting properties. These two analogs exhibited a relatively high antibacterial activity against S. aureus compared to the other MP analogs, making them a potentially attractive target for further studies. Moreover, a comparative analysis of the relationship between peptide activity and structure, as well as the calculated physicochemical parameters, may provide information that may be useful in the design of new MP analogs.     

三甲苯草酮室内生测试验

在温室条件下,以进口样品做对照,研究沈阳化工研究院40%三甲苯草酮水分散粒剂对禾本科杂草的防除效果及对小麦的安全性.结果表明:看麦娘,早熟禾对三甲苯草酮很敏感,在150 g a.i./hm2剂量下防效可达90%～100%;野燕麦的敏感性次之,在150 g a.i./hm2剂量下防效达85%,在300 g a.i./hm2剂量下防效达95%;稗草对三甲苯草酮的敏感性最差,在300 g a.i./hm2剂量下防效为60%,在600 g a.i./hm2剂量下防效为90%～95%.沈阳化工研究院样品与进口样品活性和安全性基本一致.     

Osteosarcopenia: A Narrative Review on Clinical Studies

Osteosarcopenia (OS) is defined by the concurrent presence of osteopenia/osteoporosis and sarcopenia. The pathogenesis and etiology of OS involve genetic, biochemical, mechanical, and lifestyle factors. Moreover, an inadequate nutritional status, such as low intake of protein, vitamin D, and calcium, and a reduction in physical activity are key risk factors for OS. This review aims to increase knowledge about diagnosis, incidence, etiology, and treatment of OS through clinical studies that treat OS as a single disease. Clinical studies show the relationship between OS and the risk of frailty, falls, and fractures and some association with Non-communicable diseases (NCDs) pathologies such as diabetes, obesity, and cardiovascular disease. In some cases, the importance of deepening the related mechanisms is emphasized. Physical exercise with adequate nutrition and nutritional supplementations such as proteins, Vitamin D, or calcium, represent a significant strategy for breaking OS. In addition, pharmacological interventions may confer benefits on muscle and bone health. Both non-pharmacological and pharmacological interventions require additional randomized controlled trials (RCT) in humans to deepen the synergistic effect of exercise, nutritional interventions, and drug compounds in osteosarcopenia.     

Chitosan Functionalized with Carboxyl Groups as a Recyclable Biomaterial for the Adsorption of Cu (II) and Zn (II) Ions in Aqueous Media

The modification of chitosan represents a challenging task in obtaining biopolymeric materials with enhanced removal capacity for heavy metals. In the present work, the adsorption characteristics of chitosan modified with carboxyl groups (CTS-CAA) towards copper (II) and zinc (II) ions have been tested. The efficacy of the synthesis of CTS-CAA has been evaluated by studying various properties of the modified chitosan. Specifically, the functionalized chitosan has been characterized by using several techniques, including thermal analyses (differential scanning calorimetry and thermogravimetry), spectroscopies (FT-IR, XRD), elemental analysis, and scanning electron microscopy. The kinetics and the adsorption isotherms of CTS-CAA towards both Cu (II) and Zn (II) have been determined in the aqueous solvent under variable pH. The obtained results have been analyzed by using different adsorption models. In addition, the experiments have been conducted at variable temperatures to explore the thermodynamics of the adsorption process. The regeneration of CTS-CAA has been investigated by studying the desorption process using different eluents. This paper reports an efficient protocol to synthesize chitosan-based material perspective as regenerative adsorbents for heavy metals.     

锦天化尿素质量管理问题探讨

通过对目前国际上较为先进的管理理论的介绍,对比锦天化尿素质量管理的现状,找出相对应的问题,分析了存在问题的主要原因,并提出改进对策.提出从质量战略管理开始,到加强组织建设,提高质量意识,及全员参与和以PDCA循环为工具保证的质量管理系统解决方案.     

Design,Synthesis and Biological Activity of New Amides Derived from 3-Benzhydryl and 3-sec-Butyl-2,5-dioxo-pyrrolidin-1-yl-acetic Acid

The aim of this study was to design and synthesize two new series of pyrrolidine-2,5-dione-acetamides with a benzhydryl or sec-butyl group at position 3 as potential anticonvulsants. Their anticonvulsant activity was evaluated in standard animal models of epilepsy: the maximal electroshock (MES), the 6 Hz, and the subcutaneous pentylenetetrazole (scPTZ) tests. The in vivo studies revealed the most potent anticonvulsant activity for 15 (3-(sec-butyl)-1-(2-(4-(3-trifluoromethylphenyl)piperazin-1-yl)-2-oxoethyl)pyrrolidine-2,5-dione), with ED₅₀ values of 80.38 mg/kg (MES) and 108.80 mg/kg (6 Hz). The plausible mechanism of action was assessed in in vitro binding assays, in which 15 interacted effectively with voltage-gated sodium (site 2) and L-type calcium channels at a concentration of 100 μM. Subsequently, the antinociceptive activity of compounds 7 and 15 was observed in the hot plate test of acute pain. Moreover, compounds 7 , 11 and 15 demonstrated an analgesic effect in the formalin test of tonic pain. The hepatotoxic properties of the most effective compounds ( 7 , 11 and 15 ) in HepG2 cells were also investigated.