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The processes of hydrogen reduction of silicon and germanium chlorides under the conditions of high-frequency (40.68 MHz) counteracted arc discharge stabilized between two rod electrodes are investigated. The main gas-phase and solid products of plasma-chemical transformations are determined. Thermodynamic analysis of SiCl4 + H2 and GeCl4 + H2 systems for optimal process parameters was carried out. Using the example of hydrogen reduction of SiCl4 by the method of numerical modeling, gas-dynamic and thermal processes for this type of discharge are investigated. The impurity composition of gas-phase and solid reaction products is investigated. The possibility of single-stage production of high-purity Si and Ge mainly in the form of compact ingots, as well as high-purity chlorosilanes and trichlorogermane, is shown. [ABSTRACT FROM AUTHOR]

Simulation of one-stage synthesis of composite nanoparticles of titanium dioxide and silicon dioxide in the working zone of a plasmachemical reactor by the chloride method based on the joint oxidation of titanium and silicon tetrachlorides was carried out. The developed synthesis model takes into account the possibility of aggregation not only of titanium dioxide particles that form the cores of composite particles, but also of silicon dioxide particles that do not participate in the formation of the shell. Comparison of the results of calculations by different models is carried out: the size of the cores, the thickness of the shell, and the number of particles of various types. [ABSTRACT FROM AUTHOR]

Carbon tetrachloride (CCl4) is a liquid that is colorless, transparent, inflammable, and volatile. Its central carbon atom is surrounded by four Cl- atoms. As a result, the objective of this effort was to estimate the anti-oxidant properties of silver nanoparticles (AgNPs) made utilizing aqueous plant extracts from Taraxacum officinale leaves. A green synthesis of AgNPs using a synergistic aqueous extract from T. officinale leaves was tested against liver damage in rats caused by CCl4. The rats were randomly distributed into seven groups: Group 1: Control group, Group 2: Olive oil group, Group 3: AgNPs-treated group (100 mg/kg BW.), Group 4: AgNPs-treated group (200 mg/kg BW.), Group 5: CCl4 + Olive oil group, Group 6: (CCl4 + Olive Oil) + 100 mg/kg of AgNPs-treated group, and Group 7: (CCl4 + Olive oil) + 200 mg/kg of AgNPstreated group one a week for 6 weeks. This study demonstrated a sustainable method for synthesizing AgNPs utilizing T. officinale leaf (TOL) extract. To characterize the synthesized T. officinale leaf-silver nanoparticles (TOL-AgNPs), various microscopic and spectroscopic methods were used. The effectiveness of the biosynthesized TOL-AgNPs against CCl4 was tested to assess their antioxidant potential. The antioxidant properties of synthetic TOL-AgNPs were also evaluated. Histopathological research showed that all groups treated with nanoextract had less severe inflammatory responses. Our findings demonstrated that AgNPs synthesized using the leaves of T. officinale possess a potential anti-oxidant activity against CCl4-induced liver injury in rats. [ABSTRACT FROM AUTHOR]

The present research was performed to estimate both the phytochemistry and pharmacological potential of Swietenia mahagoni leaves in validated animal models. The shade dried and powdered leaves were extracted with different organic solvents and after successive extraction, the aqueous extract was subjected to preliminary phytochemical study for identification of various phytochemicals. The fixed-dose method for acute toxicity was performed following the OECD guidelines 420. The hepatoprotective property of the aqueous and methanolic extracts was studied against paracetamol and carbon tetrachloride models in rats. Groups that are treated with aqueous, methanolic extracts and Silymarin depicted an important restoration of wet liver volume and weight near to its normal conditions. Toxic effects produced by carbon tetrachloride and paracetamol were significantly controlled with both the extracts by restoration of levels of the biochemistry of liver function, with that of standard silymarin. The toxicant decreased Catalase and SOD activities of the liver. The histopathological changes like necrosis, and fatty changes (steatosis), etc were fully or partly prevented in treated animals using extract. The results are due to the presence of flavonoids, alkaloids, saponins, steroids, tannins, and glycosides in both the extracts are responsible for hepatoprotective activity. A dose-dependent hepatoprotective effect was produced with both the extracts. [ABSTRACT FROM AUTHOR]

With the aim to interpret results of gas-phase chromatography experiments on volatility of group- 4 tetrachlorides and oxychlorides including those of Rf, adsorption enthalpies of these species on neutral, and modified quartz surfaces were estimated on the basis of relativistic, two-component Density Functional Theory calculations of MCl4, MOCl2, MCl6- -, and MOCl4 ² with the use of adsorption models. Several mechanisms of adsorption were considered. In the case of physisorption of MCl4, the trend in the adsorption energy in the group should be Zr > Hf > Rf, so that the volatility should change in the opposite direction. The latter trend complies with the one in the sublimation enthalpies, △Hsub, of the Zr and Hf tetrachlorides, i.e., Zr < Hf. On the basis of a correlation between these quantities, △Hsub(RfCl4) was predicted as 104.2 kJ/mol. The energy of physisorption of MOCl2 on quartz should increase in the group, Zr < Hf < Rf, as defined by increasing dipole moments of these molecules along the series. In the case of adsorption of MCl4 on quartz by chemical forces, formation of the MOCl2 or MOCl4 ²- complexes on the surface can take place, so that the sequence in the adsorption energy should be Zr > Hf > Rf, as defined by the complex formation energies. In the case of adsorption of MCl4 on a chlorinated quartz surface, formation of the MCl6 ²- surface complexes can occur, so that the trend in the adsorption strength should be Zr ≤ Hf < Rf. All the predicted sequences, showing a smooth change of the adsorption energy in the group, are in disagreement with the reversed trend Zr ≈ Rf < Hf, observed in the "one-atom-at-a-time" gasphase chromatography experiments. Thus, currently no theoretical explanation can be found for the experimental observations. [ABSTRACT FROM AUTHOR]

The aim of the study was to investigate in vitro potential antioxidant and hepatoprotective effects of methanolic extracts from the aerial parts of Matricaria pubescens, Centaurea incana, and Santolina africana, against carbon tetrachloride induced liver damage in rats. The different aerial parts of three methanolic extracts, exhibited antioxidant activity in the DPPH free radical (IC50, 0.032, 0.087 and 0.044 mg/ml) respectively. The reducing ability of the extracts showed a dose-dependent trend increasing with increase in the concentrations of the extracts. The antioxidant activity of samples at the concentration of 2 mg/ml was reflected in their ability to inhibit the bleaching of β-carotene. Treated groups with extracts of studied three plants showed decrease in plasma levels of AST, ALT, ALP, and an increase in plasma catalase levels activities, while hepatic MDA decreased and catalase increased as compared to carbon tetrachloride treated groups. In consistency with in vivo and in vitro results, extracts of all three plants ameliorated the carbon tetrachloride extensive damage to liver tissue of treated animals, but, Santolina africana extract was the most efficient. [ABSTRACT FROM AUTHOR]

Experiments on gas-phase chemistry for chlorides have been conducted to clarify chemical properties of the first superheavy element, rutherfordium (Rf), Z = 104. However, adsorption enthalpies obtained in each experiment are not the same, even for those of the homologues Zr and Hf. In the present study, off-line isothermal gas chromatography was done using long-lived radioactive tracers to obtain reliable adsorption enthalpies for ZrCl4 and HfCl4 when adsorbed on a quartz glass surface. To simulate a column surface modified by a chlorinating reagent in on-line experiments, chromatography was also performed using a chlorinated column. A newly developed analytical method which is independent of experimental parameters and uncertain physical quantities was applied to determine the adsorption enthalpies. The obtained enthalpies for ZrCl4 and HfCl4 were 101.3 ± 4.0 kJ mol-1 and 98.1 ± 3.1 kJ mol-1 for the non-treated column, respectively, and those for the chlorinated column were 85.1 ± 4.5 kJ mol-1 and 84.2 ± 3.3 kJ mol-1, respectively. [ABSTRACT FROM AUTHOR]

Single-stage synthesis of composite nanoparticles of titanium dioxide and silicon dioxide in the test section of a plasma-chemical reactor with the use of a chloride method based on joint oxidation of titanium and silicon tetrachlorides with preliminary mixing of the reactants by means of bubbling is simulated. Within the framework of the model developed in the study, data on the size of the composite particle core, particle shell thickness, and number of particles with and without the shell are obtained. [ABSTRACT FROM AUTHOR]

The uranyl tetrachloride dianion (UO2Cl42-) is observed in the gas phase using electrospray ionization and investigated by photoelectron spectroscopy and relativistic quantum chemical calculations. Photoelectron spectra of UO2Cl42- are obtained at various photon energies and congested spectral features are observed. The free UO2Cl42- dianion is found to be highly stable with an adiabatic electron binding energy of 2.40 eV. Ab initio calculations are carried out and used to interpret the photoelectron spectra and elucidate the electronic structure of UO2Cl42-. The calculations show that the frontier molecular orbitals in UO2Cl42- are dominated by the ligand Cl 3p orbitals, while the U-O bonding orbitals are much more stable. The electronic structure of UO2Cl42- is compared with that of the recently reported UO2F42- [P. D. Dau, J. Su, H. T. Liu, J. B. Liu, D. L. Huang, J. Li, and L. S. Wang, Chem. Sci. 3 1137 (2012)]. The electron binding energy of UO2Cl42- is found to be 1.3 eV greater than that of UO2F42-. The differences in the electronic stability and electronic structure between UO2Cl42- and UO2F42- are discussed. [ABSTRACT FROM AUTHOR]

The empty-level structures and formation of negative ion states via resonance attachment of low-energy (0-15 eV) electrons into vacant molecular orbitals in a series of non-steroidal anti-inflammatory drugs (NSAIDs), namely aspirin, paracetamol, phenacetin, and ibuprofen, were investigated in vacuo by electron transmission and dissociative electron attachment (DEA) spectroscopies, with the aim to model the behavior of these antipyretic agents under reductive conditions in vivo. The experimental findings are interpreted with the support of density functional theory calculations. The negative and neutral fragments formed by DEA in the gas phase display similarities with the main metabolites of these commonly used NSAIDs generated in vivo by the action of cytochrome P450 enzymes, as well as with several known active agents. It is concluded that xenobiotic molecules which possess pronounced electron-accepting properties could in principle follow metabolic pathways which parallel the gas-phase dissociative decay channels observed in the DEA spectra at incident electron energies below 1 eV. Unwanted side effects as, e.g., hepatoxicity or carcinogenicity produced by the NSAIDs under study in human organism are discussed within the 'free radical model' framework, reported earlier to describe the toxic action of the well-known model toxicant carbon tetrachloride. [ABSTRACT FROM AUTHOR]

We present a theoretical study of vibrational and thermal effects on the dipole polarizability of methane and carbon tetrachloride. Using a fourth order Taylor expansion in rectilinear normal coordinates of the potential and property surfaces we solve the vibrational problem using vibrational structure theory, e.g., through vibrational self-consistent-field or vibrational configuration-interaction theory. For each vibrational state we calculate in addition the vibrational state average polarizability. Constructing the vibrational partition function by “brute force” allows for prediction of thermal effects on the dipole polarizability. The method is not restricted in any way to polarizabilities nor to the specific representation of the potential and property surfaces employed in this work. Any molecular property with a suitable normal coordinate representation may be considered. We discuss the performance of vibrational self-consistent field as compared to vibrational configuration interaction and study in detail the convergence of the former method with respect to the number of vibrational states included in the thermal averaging. Based on calculations including up to 170 000 vibrational self-consistent-field states we present thermal effects on the dipole polarizability of methane and carbon tetrachloride in the temperature ranges 0–1100 and 0–500 K, respectively. The predicted thermal effect on the dipole polarizability of methane is found to be ∼0.8% which compare well with previous experimental measurements. [ABSTRACT FROM AUTHOR]

Correlation in the photoionization dynamics of carbon tetrafluoride is studied in the framework of the time-dependent density-functional theory (TDDFT) approach by employing a multicentric basis set expansion of the scattering wave function linear combination of atomic orbitals (LCAO) TDDFT. Results obtained with the statistical average of orbital potentials and LB94 exchange-correlation (xc) potentials are compared with photoabsorption, photoionization, and electron-scattering experiments as well as with past theoretical calculations. Inadequacies in both the Vxc parametrizations employed have been suggested from the analysis of the intensity plots for the D 2A1 ionization. The formation of resonant scattering states in selected continuum channels has been studied through the analysis of the dipole-prepared scattering wave function; our findings are then compared with results of electron-scattering calculations. Overall, the LCAO-TDDFT results highlight the effectiveness of the approach for the calculation of the unbound spectrum of fairly large molecules. [ABSTRACT FROM AUTHOR]

The dipole-quadrupole and dipole-octopole polarizabilities A and E of TiCl4, ZrCl4, and HfCl4 have been determined from collision-induced light-scattering experiments. Our respective experimental results for |A| are (165±10), (110±30), and (140±20) e2a03Eh-1, whereas |E| is determined to be (675±125), (750±200), and (670±400) e2a04Eh-1. Theory predicts values convincingly close to experiment, as A=(181.4±9.1), (167.6±8.4), and (139.8±7.0) e2a03Eh-1, and E=(-671±67), (-688±69), and (-574±57) e2a04Eh-1. In addition our quantum chemical ab initio calculations give reliable values for the dipole polarizability α, as well as for the octopole and hexadecapole moments Ω and [uppercase_phi_synonym] for all three substances. [ABSTRACT FROM AUTHOR]

The dipole-quadrupole and dipole-octopole polarizabilities A and E of TiCl4, ZrCl4, and HfCl4 have been determined from collision-induced light-scattering experiments. Our respective experimental results for |A| are (165±10), (110±30), and (140±20) e2a03Eh-1, whereas |E| is determined to be (675±125), (750±200), and (670±400) e2a04Eh-1. Theory predicts values convincingly close to experiment, as A=(181.4±9.1), (167.6±8.4), and (139.8±7.0) e2a03Eh-1, and E=(-671±67), (-688±69), and (-574±57) e2a04Eh-1. In addition our quantum chemical ab initio calculations give reliable values for the dipole polarizability α, as well as for the octopole and hexadecapole moments Ω and [uppercase_phi_synonym] for all three substances. [ABSTRACT FROM AUTHOR]

Our initial study on the performance of molecular polarization methods close to a positive point charge [M. Masia, M. Probst, and R. Rey, J. Chem. Phys. 121, 7362 (2004)] is extended to the case in which a molecule interacts with a real cation. Two different methods (point dipoles and shell model) are applied to both the ion and the molecule. The results are tested against high-level ab initio calculations for a molecule (water or carbon tetrachloride) close to Li+, Na+, Mg2+, and Ca2+. The monitored observable is in all cases the dimer electric dipole as a function of the ion-molecule distance for selected molecular orientations. The moderate disagreement previously obtained for point charges at intermediate distances, and attributed to the linearity of current polarization methods (as opposed to the nonlinear effects evident in ab initio calculations), is confirmed for real cations as well. More importantly, it is found that at short separations the phenomenological polarization methods studied here substantially overestimate the dipole moment induced if the ion is described quantum chemically as well, in contrast to the dipole moment induced by a point-charge ion, for which they show a better degree of accord with ab initio results. Such behavior can be understood in terms of a decrease of atomic polarizabilities due to the repulsion between electronic charge distributions at contact separations. It is shown that a reparametrization of the Thole method for damping of the electric field, used in conjunction with any polarization scheme, allows to satisfactorily reproduce the dimer dipole at short distances. In contrast with the original approach (developed for intramolecular interactions), the present reparametrization is ion and method dependent, and corresponding parameters are given for each case. [ABSTRACT FROM AUTHOR]

We used time-resolved two-photon photoemission (2PPE) spectroscopy to investigate the photochemical behavior, the interfacial electronic structure, and the fate of photogenerated hot electron for carbon tetrachloride adsorbed on Ag(111). The photodissociation cross section was determined over a wide range of photon energy from 1.62 to 5.69 eV, which suggested a low-lying electron affinity level of adsorbed CCl4. A CCl4-derived unoccupied state located at 3.41 eV above the Fermi level was attributed to an image potential (IP) state based on its binding energy and effective mass. Polarization dependence of the 2PPE signal revealed that the IP state was populated by an indirect excitation process involving scattering of photoexcited hot electrons rather than direct electronic transition from a bulk band. The lifetime of the IP state was much shorter on the CCl4-covered Ag(111) surface than on the clean one, implying that the electron in the IP state is scavenged effectively by CCl4, probably through dissociative attachment to it. These results are significant in the sense that they provide dynamical evidence for a new relaxation pathway of the IP state in addition to the more common pathway involving back transfer of electron to the substrate. [ABSTRACT FROM AUTHOR]

Temperature and concentration dependent infrared spectra were recorded for binary solutions of ethanol-hexane, ethanol-carbon tetrachloride, and ethanol-cyclopentane. The temperature range covered was 198 K to 298 K; concentrations ranged from 0.45 mole percent to 4.0 mole percent ethanol. Changes in the OH stretch frequency are consistent with the formation of ethanol clusters (EtOH)[sub n], where n ranges from 2 to 6. The geometry, OH stretch frequency and proton chemical shift for 14 different ethanol clusters ranging from monomer to hexamer in cyclic and linear arrangements were investigated using density functional methods (B3LYP/6-31+G[sup *]). These clusters include both gauche and anticonformers of the monomer unit. The OH stretch frequency calculations were compared to experimental Fourier transform infrared measurements made as a function of concentration and temperature for dilute ethanol in hexane binary mixtures. Analysis of the O-H stretch frequency data (3100 to 3700 cm[sup -1]) indicate the presence of small clusters of ethanol. The data indicate that at the lower temperatures the clusters are primarily cyclic tetramers, pentamers, and hexamers. This infrared data is in excellent agreement with recent concentration and temperature dependent nuclear magnetic resonance chemical shift investigations that indicate a dramatic change in cluster size with concentration and temperature. [ABSTRACT FROM AUTHOR]

The authors have modeled the one-stage synthesis of titania and silica composite nanoparticles in the working zone of a plasmachemical reactor by the chloride method based on separate oxidation of titanium and silicon tetrachlorides with pre-mixing of the reagents by bubbling. Within the framework of the developed synthesis model, the authors have obtained data on the size of the nuclei of the composite particles, the shell thickness, and the ratio of the number of shell-coated and uncoated particles. [ABSTRACT FROM AUTHOR]

Highlights • HCl, H 2 , SiCl 2 , SiHCl 3 , SiH 2 Cl 2 , SiCl 4 can all dissociatively adsorb at some sites. • HCl not affected by coverage, SiCl 2 prefer higher, H 2 lower & SiCl 4 in between. • Formation of adsorbed SiCl 2 from surface Si atom had highest barrier of 3.62 eV. • Formation of desorbed SiHCl 3 from adsorbed SiCl 2 had barrier of 1.07 eV. Abstract The interaction of chlorosilanes and the silicon surface is an important part of reaction processes, such as hydrochlorination and chemical vapor deposition, involved in the production of high purity silicon. We used plane-wave based density functional theory (DFT) to investigate periodic slabs of the Si(100)-c(4 × 2) surface for adsorption of H 2 , HCl, SiCl 2 , dichlorosilane (SiH 2 Cl 2 or DCS), trichlorosilane (SiHCl 3 or TCS) and silicon tetrachloride (SiCl 4 or STC). The effects of surface coverage, molecule orientation, adsorption site and multiple molecule adsorption were studied. All the molecules could undergo dissociative chemisorption in the right orientation and site placement, with HCl and SiCl 2 possessing the strongest binding energies. The H 2 molecule preferred lower coverage, the HCl molecule was not much affected by coverage while the SiCl 2 molecule strongly preferred higher coverage and the STC molecule was affected negatively by both too high or low coverage. The elementary steps leading to transfer of surface crystal silicon atoms to gas phase molecules as part of the chlorination or hydrochlorination process were then looked at through reaction pathway analysis. The formation of SiCl 2 from a surface dimer Si atom was found to prefer an intradimer route with a reaction barrier of 3.62 eV (83.48 kcal/mol), going down to 3.10 eV (71.49 kcal/mol) after removal of the first surface Si atom. The subsequent formation of TCS from this SiCl 2 was found to have reaction barrier of 1.07 eV (24.68 kcal/mol). STC could also be formed from this SiCl 2 molecule with a reaction barrier of 2.86 eV (65.95 kcal/mol). [ABSTRACT FROM AUTHOR]

Examines the electron transmission and dissociative electron attachment spectra of 14 methyl chlorides and tetrachlorides. Comparison of the experimental resonance energies with the total electron scattering cross sections; Discussion of the sizes of tin and silicon derivatives; Implications of size measurement of fragment anions on compounds.

The upward thermal diffusion cloud chamber was used to measure the critical supersaturations for homogeneous nucleation of droplets from the supersaturated vapors of tin and titanium tetrachlorides. The measured supersaturations are in good agreement with the predictions of the classical theory of nucleation. Trends in free energy barrier are correctly predicted by the classical theory for carbon, silicon, tin, and titanium tetrachlorides. However, the classical barrier does not reflect the binding energies in the critical clusters. According to the classical theory, the size of the nucleus of SiCl4 ranges from 60 to 120 molecules while for TiCl4 it varies from 35 to 65 molecules in the temperature range of 240–310 K. The classical theory predicts a linear log J vs 1/T relationship. Corresponding states correlations are used to locate general trends and correlate them with molecular properties. Titanium tetrachloride deviates from the ‘‘simple fluid’’ behavior observed for CCl4, SiCl4, and even SnCl4. This deviation must reflect a modified intermolecular potential for TiCl4 as compared to a simple fluid potential. [ABSTRACT FROM AUTHOR]

Focuses on a study that examined the deposition of amorphous silicon films from silicon tetrachloride glow discharges. Purpose of deposition techniques by radio frequency plasma; Description of the deposition chamber used in the study; Methods used to analyze the gas phase of the discharge.

A lattice gas model of tetrahedral molecules on a bcc lattice was considered in which a lattice site can be either vacant or occupied by a molecule in either of the two orientations in which the bonds of the molecule point toward neighboring lattice sites. If two molecules occupy neighboring lattice sites, they repel with a steric bond–bond repulsion γ if each points a bond toward the other, they attract with an energy ε if exactly one points a bond toward the other, and they attract with an energy δ if neither points a bond toward the other. The Peierls argument was used to prove that an orientationally ordered phase exists in the model at sufficiently low temperatures if 2ε<γ+δ and μ>max {4ε,12ε-4δ}. The equation of state and critical point were calculated using a Guggenheim approximation. The parameters in the model were fitted to experiment using the properties of carbon tetrachloride at the critical point. The condensed phase in the model exhibits the same type of short-range orientational ordering proposed by Nishikawa and Murata to exist in liquid carbon tetrachloride. [ABSTRACT FROM AUTHOR]

Neutron experiments have been performed to measure the induced spin density distribution in single crystals of uranium tetrachloride at low temperature. A structural refinement has also established the atomic positions and thermal parameters at low temperature and these are in agreement with earlier studies. The spin-density distribution, determined with polarized neutrons, shows small but significant deviations from that expected from the single-ion crystal-field model. Fourier difference maps show a small depletion of the (5f) density near the U site and a small positive increase ∼1 Å from the U site and principally along the shorter U–Cl bonds. We ascribe this to population of a 6d (x2-y2) orbital. No significant spin density is associated with the Cl site. Model calculations are presented which qualitatively account for the observed effect and involve electron transfer from the 5f to the 6d antibonding orbital formed as a result of a covalent interaction between the U 6d and Cl p states. This is the first direct observation of covalency in systems involving 5f 6d electrons. [ABSTRACT FROM AUTHOR]

One-stage synthesis of composite titania and silica nanoparticles in the working area of a plasmachemical reactor by a chloride method, which is based on separate oxidation of titanium and silicon tetrachlorides, has been modeled for the first time. The influence of a number of parameters of the physicomathematical model on both the general size of the particles and the shell thickness has been investigated. Results of calculations for certain variants of the parameters have been given. [ABSTRACT FROM AUTHOR]

The kinetics of decomposition of tetrachloromethane (TCM) in its aqueous solutions and the kinetics of decomposition products formation was investigated under the action of DBD at atmospheric pressure in oxygen in a falling-flow reactor. The range of initial concentrations of TCM was 25-325 μmol/l, the discharge power—2-11 W and O2 flow rates—1-3 cm3/s. It is shown that the kinetics of the TCM decomposition can be described by the equation of pseudo-first kinetic order. The rate constant depended weakly on the discharge parameters and was ~ 5 s−1. The energy efficiency of the decomposition, depending on the parameters, was 0.1-1.3 molecules per 100 eV. When the residence time of the solution with the discharge zone is more than 1 s, it is possible to achieve almost 100% degree of TCM decomposition. It is shown that the main products of the TCM decomposition in the liquid phase are aldehydes and Cl− ions, and in the gas phase—the molecules CO and CO2. The results for energy efficiency are compared with the results obtained in other AOP's processes (Fenton process, photocatalytic process, the radiation process by the action of high-energy electron flux). It is shown that the action of the DBD is more effective than the action of the above processes. [ABSTRACT FROM AUTHOR]

Background: The persistent use of Funtumia africana leaves extract in the management of hepatitis and other hepatic disorders by traditional medicine practitioners has necessitated scientific evaluation to ascertain its hepatoprotective activities. Aim of the study: This study investigated hepatoprotective and curative effects of the methanol extract of Funtumia leaves against carbon tetrachloride (CCl4)-induced hepatotoxicity in rats. Methods: A total of 42 rats distributed into seven groups of six rats each were used in this study with Group 1 as the normal control that received olive only while Groups 2-7 served as test groups that were CCl4-induced intraperitoneally and treated orally with silymarin and the methanol extract, respectively. This study was carried using standard methods. Results: CCl4 induction caused significant (P < 0.05) increase in liver marker enzyme activities in the rats relative to the normal control. Furthermore, the CCl4-induced rats showed significant (P < 0.05) decrease in total protein (TP), albumin (ALB), and direct bilirubin and significant (P < 0.05) increase in total bilirubin concentrations relative to the normal control which together with the liver marker enzymes indicated liver injury and impaired liver functions. Groups treated with silymarin and the extract, respectively, showed significant (P < 0.05) decrease in liver marker enzyme activities and total bilirubin concentrations, and significant (P < 0.05) increase in TP, ALB, and direct bilirubin concentrations relative to the negative control which indicated improved liver integrity and function. Conclusion: The findings of this study suggest that methanol extract of F. africana leaves possessed hepatoprotective and curative activities and could be used for the management of hepatic disorders. [ABSTRACT FROM AUTHOR]

Abstract Background Liver injury is a serious threat for human health and life. Toll-like receptor 5 (TLR5) has reported to be a vital mediator in flagellin or tetrachloride (CCl4)-induced liver injury. However, the roles and etiology of TLR5 in hyperammonaemia (HA)-induced liver injury are poor defined. Methods HA rats were generated by intragastric administration using ammonium chloride solution. Liver status was assessed by haematoxylin and eosin (H&E) staining and measuring serum levels of liver injury markers. Immunohistochemistry (IHC) assay was used to visualize protein expression in tissues. Apoptotic index in tissues was determined by TUNEL assay. RT-qPCR assay was employed to test mRNA expression. Oxidative stress responses was assessed by detecting levels of reactive oxygen species (ROS) and related indicators. NF-κB activity was examined by TransAM NF-κB colorimetric kit. Results TLR5 was highly expressed in liver tissues of HA rats. TLR5 knockdown ameliorated HA-induced liver injury by inhibiting liver cell apoptosis. TLR5 depletion inhibited HA-induced pro-inflammatory cytokine expression in liver tissues, but had no effect on the infiltration of T and macrophage cells into liver tissues. TLR5 silencing impaired HA-induced oxidative stress responses in hepatocytes, but not in hepatic stellate cells (HSCs). TLR5 downregulation inhibited HA-induced activation on TLR5/NF-κB and TLR5/MAPK signaling pathways. Conclusion TLR5 silencing reduced HA-induced liver injury by inhibiting hepatocyte apoptosis, oxidative stress and inflammation responses via inactivating NF-κB and MAPK signals, deepening our understanding on the molecular mechanism of HA-induced liver injury and providing a potential therapeutic target for alleviating liver injury. Highlights • TLR5 was highly expressed in liver tissues of HA rats. • The knockdown of TLR5 ameliorated HA-induced liver injury by inhibiting hepatic cell apoptosis. • TLR5 depletion inhibited HA-induced pro-inflammatory cytokine expression in liver tissues of rats. • TLR5 silencing impaired HA-induced oxidative stress responses in hepatocytes. • TLR5 downregulation inhibited HA-induced activation on TLR5/NF-κB and TLR5/MAPK signaling pathways. [ABSTRACT FROM AUTHOR]

Abstract In view of the urgent need of determining polychlorinated biphenyls in the environment, we developed a highly sensitive and selective photoelectrochemical (PEC) aptasensor for determination of 3,3′,4,4′-tetrachlorobiphenyl (PCB77) by immobilizing aptamer on N-doped TiO 2 nanotubes (N-doped TiO 2 NTs). To improve analytical performance of the PEC sensor, the complementary DNA functionalized CdS quantum dots (DNA-CdS QDs) were introduced onto N-doped TiO 2 NTs by hybridization. In addition of PCB77, owing to high affinity of aptamer to PCB77, PCB77-aptamer complexes were formed by being bound of PCB77 whilst DNA-CdS QDs were released from the sensing surface. The complexes with poor conductivity hindered the interfacial electron transfer, leading to the photocurrent decrease. The more important is the release of DNA-CdS QDs enhanced the photocurrent decrease, playing the role of signal amplification. The photocurrent change was utilized to detect PCB77 quantitatively. The PEC aptasensor exhibited excellent analytical performance for detection of PCB77 with wide linear range of 0.1–100 ng/L and a low detection limit of 0.1 ng/L. It manifested outstanding selectivity for PCB77 in control experiments by employing six interferents which had similar structure or coexisted with PCB77. Besides, the PEC aptasensor was used to detect the content of PBC77 in the environment. Highlights • A simple and novel PEC aptasensor based on N-doped TiO 2 NTs was design for detection of PCB77. • Through introducing DNA-CdS QDs on sensing interface, the photocurrent of the aptasensor was enhanced and the detection signal for PCB77 was amplified. • The PEC aptasensor exhibited excellent analytical performance with high sensitivity and selectivity for detection of PCB77. [ABSTRACT FROM AUTHOR]

The first catalytic enantioselective aldol reaction of various unprotected carboxylic acids is described. In the presence of a chiral bis(phosphine oxide) as a Lewis base catalyst, carboxylic acids were activated with silicon tetrachloride to form the corresponding bis(trichlorosilyl)enediolates in situ, which subsequently underwent an aldol reaction with an aldehyde or a ketone to produce β‐hydroxycarboxylic acids in high enantioselectivities of up to 92 % ee. Various unprotected carboxylic acids undergo enantioselective aldol reactions in the presence of a chiral phosphine oxide as a Lewis base catalyst. The carboxylic acids were activated with silicon tetrachloride to form the bis(trichlorosilyl)enediolates in situ, which subsequently underwent an aldol reaction with an aldehyde or a ketone to produce β‐hydroxycarboxylic acids in high enantioselectivities of up to 92 % ee. [ABSTRACT FROM AUTHOR]

The by-product silicon tetrachloride (SiCl 4 ) was usually obtained from polysilicon industry and was a cheaper alternative precursor. An economic method to produce silica aerogel using silicon tetrachloride under ambient pressure drying was presented in this work, which can also solve the pollution problem during the by-product silicon tetrachloride treatment process. The prepared aerogel samples were characterized by scanning electron microscopy, Brunauer-Emmett-Teller analysis, thermal conductivity analysis, contact angle test, Fourier transform infrared spectroscopy and thermogravimetric analysis. It was found that the molar ratio of H 2 O/SiCl 4 could affect the properties of aerogels seriously. The density and thermal conductivity first decreased and then increased as the molar ratio increased from 13 to 32. The porosity showed an opposite trend with the density. Silica aerogel with high specific surface area (856.7 m 2 /g), low density (0.077 m 3 /g) and low thermal conductivity (0.0213 W/m·k) were obtained at the optimal conditions when the molar ratio was 25. The resulting aerogel is also mesoporous material with super hydrophobicity and have a huge application in thermal insulation field. [ABSTRACT FROM AUTHOR]

In this study, we systematically investigated the physicochemical properties, hepatoprotective activities and the underlying mechanisms of Agaricus bisporus polysaccharide (FPS). The physicochemical evaluations indicate that FPS is mainly composed of glucose, mannose, galactose, fucose, arabinose and glucuronic acid with the mole percentages of 70.30%, 8.70%, 12.88%, 0.79%, 5.04% and 1.57%, respectively. The results of methylation analysis indicated that FPS mainly included 1-linked-glc, 1,4-linked-glc, 1,6-linked-glc, 1,3-linked-gal and 1,3,6-linked-man glycosidic bonds. The results from hepatoprotective studies showed that FPS significantly decreased the liver index, serum gamma-glutamyltranspeptidase (GGT), alanine aminotransferase (ALT), alkaline phosphatase (ALP), aspartate aminotransferase (AST) activities and malondialdehyde (MDA) contents in liver tissue, and increased antioxidant capacities of hepatic glutathione (GSH) and superoxide dismutase (SOD). Furthermore, histological examination of liver tissues showed that FPS alleviated CCl 4 -induced liver injury. Finally, the Western blot results showed that FPS could significantly decrease the expression levels of TGF-β1 and Smad3 in the liver. These results together suggest that FPS possesses hepatoprotective effect against CCl 4 -induced liver damage, in part through the downregulation of TGF-β1/Smad signaling pathway, therefore FPS could be considered as a hepatoprotective medicine or functional food. [ABSTRACT FROM AUTHOR]

Graphical abstract Designed multi-layered TiO 2 PAs by various treatments. Highlights • Multi-layered TiO 2 photoanodes are prepared by spin coating process. • A novel device structure of DSSC is fabricated. • Tuning photoanode structure from monolayer to multilayer, the efficiency is significantly improved. • This enhanced efficiency is mainly attributed to the improved charge transfer process. Abstract Multi-layered titanium dioxide photoanodes consisting of various layers treated by titanium tetrachloride and titanium isopropoxide are obtained for dye-sensitized solar cells. This process is successfully implemented to fabricate highly efficient photoanodes for dye-sensitized solar cells, demonstrating that performance of the cells is improved by optimizing the multi-layered titanium dioxide photoanodes. Charge-transfer kinetics of the devices is analyzed by impedance spectroscopy. The conversion efficiency of the devices is considerably boosted from 6.73% to 8.43% by tuning the photoanode structure from monolayer to multilayer. The best power conversion efficiency is obtained on the device with a photoanode composed of double pre-treated and one post-treated layers of titanium dioxide. This enhanced efficiency is mainly attributed to the improved charge transfer process characterized by a larger resistance at electrolyte/photoanode interface, exhibiting a longer electron lifetime. [ABSTRACT FROM AUTHOR]

Abstract: Oxidative stress and inflammatory response are well known to be involved in the pathogenesis of acute liver injury. This study was performed to examine the hepatoprotective effect of ginsenoside Rg1 (Rg1) against CCl4‐induced acute liver injury, and further to elucidate the involvement of Nrf2 signaling pathway in vivo and in vitro. Mice were orally administered Rg1 (15, 30, and 60 mg/kg) or sulforaphane (SFN) once daily for 1 week prior to 750 μL/kg CCl4 injection. The results showed that Rg1 markedly altered relative liver weights, promoted liver repair, increased the serum level of TP and decreased the serum levels of ALT, AST and ALP. Hepatic oxidative stress was inhibited by Rg1, as evidenced by the decrease in MDA, and increases in GSH, SOD, and CAT in the liver. Further research demonstrated that Rg1 suppressed liver inflammation response through repressing the expression levels of inflammation‐related genes including TNF‐α, IL‐1β, IL‐6, COX‐2, and iNOS. In addition, Rg1 enhanced antioxidative stress and liver detoxification abilities by up‐regulating Nrf2 and its target‐genes such as GCLC, GCLM, HO‐1, NQO1, Besp, Mrp2, Mrp3, Mrp4, and down‐regulating Cyp2e1. However, the changes in Nrf2 target‐genes, as well as ameliorative liver histology induced by Rg1 were abrogated by Nrf2 antagonist all‐transretinoic acid in vivo and Nrf2 siRNA in vitro. Overall, the findings indicated that Rg1 might be an effective approach for the prevention against acute liver injury by activating Nrf2 signaling pathway. [ABSTRACT FROM AUTHOR]

The reaction of tin tetrachloride with a series of variously substituted α-hydroxyphosphonates (L) in anhydrous dichloromethane produces new octahedral tin complexes of the type [SnCl 4 L 2 ]. These adducts were characterized by multinuclear ( 1 H, 13 C, 31 P and 119 Sn) NMR, IR spectroscopy, and elemental analysis. The NMR data show that these complexes exist in solution as mixtures of cis and trans isomers. Moreover, the solution behavior of these complexes in the presence of excess ligand was investigated with variable temperature NMR using the coalescence temperature method. The resulting metal-ligand exchange activation energies were determined, showing values in the range 50–52 kJ/mol. The remote substituent effect on the metal-ligand interaction was also studied and compared with closely related phosphoryl-tin complexes. [ABSTRACT FROM AUTHOR]

Cyclocarya paliurus (Batal.) Iljinskaja ( C. paliurus ), known locally as ‘sweet tea tree’, is commonly cultivated in China. Flavonoids from Cyclocarya paliurus (Batal.) Iljinskaja (FC) is reported to exhibit multiple biological effects, including anti-inflammatory, anti-oxidant and anti-diabetic activities. However, their influence on carbon tetrachloride (CCl 4 )-induced acute liver injury remains unclear. This study was designed to investigate the hepatoprotective effect of total flavonoids from C. paliurus leaves. Results revealed that flavonoids from C. paliurus significantly decreased CCl 4 -induced elevation of activities of aspartate transaminase (AST), alanine transaminase (ALT) and superoxide dismutase (SOD) as well as the level of malondialdehyde (MDA), and markedly increased the levels of SOD, total antioxidant capacity (T-AOC) and glutathione peroxidase (GSH-Px) compared with the model group. Structures of mainly compounds were elucidated by nuclear magnetic resonance (NMR), mass spectrometry (MS) spectroscopic and chemical analyses. This study clearly shows that flavonoids from C. paliurus exert a potent protective effect against CCl 4 -induced acute liver injury in mice. Its hepatoprotective effect appears to be closely associated with its antioxidant activity. The results indicated that flavonoids from C. paliurus leaves could be considered as a potent food supplement in the prevention of acute liver injury. [ABSTRACT FROM AUTHOR]

The chemical shifts and self-diffusion coefficients of methylxanthines (caffeine, theophylline and theobromine) and tetramethylsilane in the binary solvent methanol‑ d 4 –carbon tetrachloride have been investigated by 1 H NMR and 1 H PGSE NMR methods at the temperatures of 298, 303 and 313 K. The concentration dependences of tetramethylsilane self-diffusion coefficients have an inflection point and the concentration dependences of methylxanthines self-diffusion coefficients have a minimum in the region of 0.2–0.4 mol fraction of methanol‑ d 4 . The self-diffusion coefficient values for theophylline and theobromine are the same and lower than the corresponding value for caffeine. It has been found that rise in the methanol concentration leads to an increase in the chemical shifts of the imidazole ring protons (CH) in the methylxanthine molecule, which indicates a change in the methylxanthines molecular association degree. The differences in the concentration dependences of the self-diffusion coefficients were interpreted by taking into account the molecular association within the framework of the Stokes-Einstein equation. [ABSTRACT FROM AUTHOR]

An effective method to rapidly determine the presence of seven unmetabolized synthetic musks in human urine samples is developed. The target musks are five synthetic polycyclic musks (i.e., celestolide (ADBI), phantolide (AHMI), traseolide (ATII), galaxolide (HHCB), tonalide (AHTN)), and two nitro-aromatic musks (i.e., musk xylene (MX) and musk ketone (MK)). The method involved an ultrasound-assisted emulsification microextraction (USAEME) coupled with gas chromatography–mass spectrometry (GC–MS). The factors that affect USAEME efficiency were optimized in detail, and the optimized procedure involved the rapid injection of 50 μL of carbon tetrachloride into 1.0 mL of urine sample (contained 0.1-g of sodium chloride) in a conical bottom glass tube. After 1.0 min ultrasonication and 3 min centrifugation (at 7000 rpm), the sedimented extract 10 μL was directly injected into the GC–MS system. The limits of quantitation (LOQs) varied from 0.1 to 0.5 ng/mL. The precisions for both repeatability and reproducibility were <8%. The trueness varied from 79 to 96% with the RSD ranging from 2 to 8%. The total concentrations of the seven unmetabolized target musks in collected human urine samples were in the range from 0.93 to 3.74 ng/mL. HHCB and AHTN were detected in all the collected samples, and the daily excretion doses were evaluated. [ABSTRACT FROM AUTHOR]

Metal organic frameworks (MOF) are a type of nanoporous materials with large specific surface area, which are especially suitable for gas separation and storage. In this work, we report a new approach of crosslinking UiO-66-(OH) 2 to enhance its hydrogen storage capacity. UiO-66-(OH) 2 was synthesized using hafnium tetrachloride (HfCl 4 ) and 2, 5-dihydroxyterephthalic acid (DTPA) through a canonical modulated hydrothermal method (MHT), followed by a post-synthesis modification, which is to form a crosslinking structure inside the porous structure of UiO-66-(OH) 2 . During the modification process, the phenolic hydroxyl groups on the UiO-66-(OH) 2 reacted with methanal, and HCl aqueous solution and triethylamine served as catalyst (the products denoted as UiO-66-H and UiO-66-T, respectively). Powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), 13 C nuclear magnetic resonance spectroscopy ( 13 C NMR) proved that the crosslinking was formed. The BET specific surface area and the average adsorption pore size of UiO-66-H and UiO-66-T significantly increased after modification. The hydrogen storage capacity of UiO-66-H reached a maximum of 3.37 wt% (16.87 mmol/g) at 77 K, 2 MPa. Hydrogen adsorption enthalpy of UiO-66-T was 0.986 kJ/mol, which was higher than that of UiO-66-(OH) 2 (0.695 kJ/mol). This work shows that UiO-66-(OH) 2 is a promising candidate for potential application in high-performance hydrogen storage. [ABSTRACT FROM AUTHOR]

The vapor-liquid separation factors of SiCl4-A (A = SiCl4-nFn (n = 1-4) silicon fluorochloride impurities in silicon tetrachloride have been determined experimentally at 298 K by statically balancing phases. The values obtained for the SiCl4-SiCl3F, SiCl4-SiCl2F2, SiCl4-SiClF3, and SiCl4-SiF4 systems are 4.9 ± 0.8, 8.2 ± 1.2, 29.8 ± 6.1, and 42.0 ± 7.5, respectively. In the SiCl4-SiCl3F system, the vapor-liquid separation factor has also been determined by the Rayleigh distillation method: α = 5.0. The experimental data agree with the vapor-liquid separation factors estimated in conformal solution theory using parameters of the Lennard- Jones potential. [ABSTRACT FROM AUTHOR]

Abstract: Assignments of the chemical shifts of the 7‐syn and 7‐anti protons in 2‐norbornene and of the methyl groups in α‐pinene and β‐pinene have been determined by means of nuclear Overhauser effects. These results constrain competing theories of the shielding effects of double bonds. [ABSTRACT FROM AUTHOR]

The reaction of uranium tetrachloride with anhydrous liquid hydrogen cyanide yields a turquoise microcrystalline powder of tetrachloridotetraformonitrileuranium(iv), [UCl4(HCN)4]. We determined the crystal structure of this compound by powder neutron diffraction. The compound was further characterized by IR spectroscopy and thermogravimetric analysis as well as by magnetic measurements. The paramagnetic compound crystallizes in the tetragonal space group type I4̅. To the best of our knowledge this compound represents the first structurally elucidated uranium(iv) complex with HCN as a ligand. [ABSTRACT FROM AUTHOR]

We have investigated the low temperature epitaxy of high Sn content GeSn alloys in a 200 mm industrial Reduced Pressure - Chemical Vapor Deposition tool from Applied Materials. Gaseous digermane (Ge 2 H 6 ) and liquid tin tetrachloride (SnCl 4 ) were used as the Ge and Sn precursors, respectively. The impact of temperature (in the 300–350 °C range), Ge 2 H 6 and SnCl 4 mass-flows on the GeSn growth kinetics at 100 Torr has been thoroughly explored. Be it at 300 °C or 325 °C, a linear GeSn growth rate increase together with a sub-linear Sn concentration increase occurred as the SnCl 4 mass-flow increased, irrespective of the Ge 2 H 6 mass flow (fixed or varying). The Sn atoms seemed to catalyze H desorption from the surface, resulting in higher GeSn growth rates for high SnCl 4 mass-flows (in the 4–21 nm min −1 range). The evolution of the Sn content x with the F ( SnCl 4 ) 2 · F ( Ge 2 H 6 ) mass-flow ratio was fitted by x 2 ( 1 - x ) = n · F ( SnCl 4 ) 2 · F ( Ge 2 H 6 ) , with n  = 0.25 (325 °C) and 0.60 (300 °C). We have otherwise studied the impact of temperature, in the 300–350 °C range, on the GeSn growth kinetics. The GeSn growth rate exponentially increased with the temperature, from 15 up to 32 nm min −1 . The associated activation energy was low, i.e. E a  = 10 kcal mol −1 . Meanwhile, the Sn content decreased linearly as the growth temperature increased, from 15% at 300 °C down to 6% at 350 °C. [ABSTRACT FROM AUTHOR]

A mononuclear coordination complex, quinidinum-zinc(II)-trichloride (I), and a multi-component ionic complex, quinidinum iron(III) tetrachloride hydrogen chloride hydrate (II), have been synthesized and characterized by elemental analyses, IR spectra, and single crystal X-ray diffraction (CIF files nos. 1497628 (I) and 1497629 (II)). The weak hydrogen-bonding interactions exist in both complexes I and II. Both complexes crystallize in the chiral space groups with the absolute configuration. Complex I crystallizes in the orthorhombic space group P212121 with a = 7.6651(6), b = 11.4923(9), c = 24.653(2) Å, and Z = 4. Complex II crystallizes in the monoclinic space group P21 with a = 6.6425(15), b = 18.660(4), c = 10.958(3) Å, β = 104.973(3), and Z = 2. [ABSTRACT FROM AUTHOR]