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Detailed results of computer modeling of halocarbon removal rates from the atmosphere are analyzed to find simple correlations useful for improving estimations of the atmospheric lifetimes of industrial chemicals based on the rate constants for their reactions with OH and O(1D) and their UV absorption spectra. This analysis is limited to relatively long‐lived chemicals that are well mixed in the troposphere. Key Points: A new semiempirical approach is developed for obtaining total atmospheric lifetimes of halocarbons from their photochemical propertiesThe new approach yields partial lifetimes for methyl chloroform of 6.0 years for OH reaction and 48 years for stratospheric photolysisThe methyl chloroform scaling approach is shown to yield total (rather than tropospheric) lifetime estimates for long‐lived halocarbons [ABSTRACT FROM AUTHOR]

The key descriptor that dominates the kinetics of the alkaline hydrogen evolution reaction (HER) has not yet been unequivocally identified. Herein, we focus on the adsorbed hydroxyl (OHad) transfer process (OHad + e− ⇄ OH−) and reveal its crucial role in promoting the overall kinetics of alkaline HER based on Ni/Co‐modified MoSe2 model catalysts (Ni‐MoSe2 and Co‐MoSe2) that feature almost identical water dissociation and hydrogen adsorption energies, but evidently different activity trends in alkaline (Ni‐MoSe2 ≫ Co‐MoSe2) and acidic (Co‐MoSe2 ≥ Ni‐MoSe2) media. Experimental and theoretical calculation results demonstrate that tailoring MoSe2 with Ni not only optimizes the hydroxyl adsorption, but also promotes the desorption of OH− and the electron‐involved conversion of OHad to OH−, all of which synergistically accelerate the kinetics of OHad + e− ⇄ OH− and thereby the overall kinetics of the alkaline HER. [ABSTRACT FROM AUTHOR]

We present a green synthesis of fluorescent carbon quantum dots (CQDs) by using red cabbage (rc) and a one-step hydrothermal approach. The rcCQDs were characterized by various techniques such as UV-visible spectroscopy, transmission electron microscopy (TEM), high-resolution TEM, Fourier-transform infrared spectroscopy, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy. The synthesized rcCQDs exhibited an average size of 3 nm, measured by TEM, blue fluorescence, and a quantum yield of 8.3%. The highest emission band was observed at approximately 402 nm when excited at 330 nm. The rcCQDs exhibited strong antioxidant activities by scavenging 61, 56, and 91% against 2, 2-diphenyl-1-picrylhydrazyl, hydroxyl, and potassium permanganate radicals, respectively. The scavenging activity of rcCQDs was comparable with that of standard antioxidant L-ascorbic acid. Cell Counting Kit (CCK)–8 assay depicted superior bio-compatibility and negligible cytotoxicity of rcCQDs on SH-SY5Y neuroblastoma cells. They were used as a fluorescent probe for bio-labeling of Escherichia coli and Staphylococcus aureus. The viabilities of the labeled bacterial cells were analyzed by AFM and UV-visible spectroscopy. Furthermore, the rcCQDs were utilized as a fluorescent ink, an alternative to pens, and maybe suitable for paints and varnish agents. This study provides detailed mechanistic insights into the antioxidant activity of as-synthesized rcCQDs, which suggest the practical applicability of CQDs for bio-medical applications. Key points • Carbon quantum dots were prepared from red cabbage using the hydrothermal method. • The scavenging activity of rcCQDs was evaluated for DPPH, OH, and KMnO4radicals. • The rcCQDs were used for the labeling of foodborne bacteria. • The rcCQDs could be utilized as fluorescent ink. [ABSTRACT FROM AUTHOR]

Novel hydroxylated UIO-66 for gaseous elemental mercury (Hg0) removal has been considered to be an emerging method because of its economical and reusable property. Density functional theory studies were investigated to reveal the enhanced heterogeneous interaction mechanisms between mercury and hydroxylated UIO-66 with and without the presence of H2O2 vapor. The adsorption and dissociation of H2O2 and the generation mechanism of surface hydroxyls on UIO-66 were investigated. Results indicated that H2O2 preferred to disconnect the O–O bond followed by the generation of two hydroxyls in the presence of H2O2. The hydroxyl adsorbed on UIO-66 and formed the UIO-66 hydroxylation product. The interaction performances between Hg0, H2O2, and UIO-66 as well as the interaction performances between Hg0 and hydroxylated UIO-66 systems were both evaluated through binding energy and the Mulliken charge analysis. Interacted energies indicated thermodynamically favorable processes of Hg–OH formation on hydroxylated UIO-66. The Mulliken charge changes revealed an oxidative process of mercury. [ABSTRACT FROM AUTHOR]

The absorption spectra have been measured at temperatures of 7.2–300 K of a -irradiated and UV-exposed LiF crystal with an admixture of oxygen and hydroxyl. The coupling force (S) with the phonons of the lattice of the electronic–vibrational transition with the zero-phonon line 436.55 nm is determined from the ratio of the intensities of the zero-phonon line and the vibronic absorption band. Based on the value of S, the nature of the color center responsible for the absorption band of 390 nm and radiation of 490 nm is proposed. [ABSTRACT FROM AUTHOR]

• Promotion effect of active oxygen or hydroxyl on HCHO oxidation is revealed. • Synergic effect of active oxygen and hydroxyl on HCHO oxidation is proposed. • Hydroxyl promotes formate specie formation step. • active oxygen promotes formate oxidation step. Density functional theory is used to study the formaldehyde (HCHO) oxidization mechanism with or without the assist of active oxygen and hydroxyl over silver cluster. We elaborate all possible intermediates adsorption structures and energies of HCHO oxidation on the Ag 19 cluster, and propose the pathways for the active oxygen, hydroxyl and their synergistic function assisted reaction processes. It is found that the direct HCHO dehydrogenation proceeds along HCHO → CHO → CO and the HCHO dehydrogenation is the rate-determining step with a barrier energy (E b) of 1.922 eV. With the assist of active oxygen, a reaction pathway of HCHO (+O) → HCHO 2 →CHO 2 (+O) → CO 2 with the direct dehydrogenation of methylenedioxy being the rate-determining step and a E b value of 1.119 eV is demonstrated. While the reaction pathway of HCHO (+OH) → HCHOOH → HCOOH (+OH) → CHO 2 → CO 2 is favorable in the presence of hydroxyl, in which the direct formate dehydrogenation is the rate-determining step with an E b value of 1.424 eV. Combining the promotion effect of active oxygen and hydroxyl together, the preferable reaction route is HCHO (+OH) → HCHOOH → HCOOH (+OH) → CHO 2 (+O) → CO 2 with the HCOOH oxidation step as the controlling step and a low E b value of 0.837 eV. These calculation results give us a clear view of the effect of active oxygen and hydroxyl in HCHO oxidation, and offer a reasonable explanation for the experimental findings in the literature. [ABSTRACT FROM AUTHOR]

Current internal combustion engines (ICEs) are powered by fossil fuels which create the challenges of low combustion efficiency and the emission of greenhouse gases. This has negatively affected the environment, leading to global warming and climate change. Interim technologies can be implemented to reduce these effects whilst alternative technologies are being explored. This research aimed at selecting the most appropriate geometrical design of a hydroxyl booster dry cell, a device which operates on the principles of electrolysis to produce hydroxyl gas commonly referred to as Brown gas or HHO. When a voltage is applied to a body of water, it splits it into its base components, i.e. hydrogen and oxygen cold plasma, a mixture sometimes referred to as hydroxyl gas. The addition of hydroxyl gas into the combustion chamber of an ICE initiates a more complete combustion due to the explosive and diffusive nature of hydrogen accompanied by the cooling effect of water thus reducing potential for NOx formation. This leads to fuel savings, cost savings and reduced emissions. A rectangular hydroxyl booster dry cell was selected and designed, fabricated and tested for effectiveness. The HHO generator is later connected to the ICE system to check mainly on the positive contributions of this Brown's gas as HHO is popularly known. [ABSTRACT FROM AUTHOR]

Typically GaN metal-oxide-semiconductor heterojunction-field-effect transistors (MOS-HFETs) have used two separate dielectrics for the gate and access regions. However, as this article shows, with proper gate-stack engineering, a unified dielectric solution can be achieved for the transistor. HfO2 dielectrics were deposited by atomic layer deposition (ALD). Two types of oxidants were investigated, namely, water (H2O) and ozone (O3). It was found that MOS-HFETs with O3 oxidant yielded lower threshold voltage (VTH) shifts, higher maximum drain current (IDS,max) of 340 mA/mm, 20% lower ON-resistance (RON), higher peak transconductance at 112.66 mS/mm, lower hysteresis, and lower gate leakage (5.4 × 10−6 A/cm2) compared to water oxidant based MOS-HFETs with IDS,max of 240 mA/mm, 81.38 mS/mm peak transconductance, and 1.7 × 10−4 A/cm2 gate leakage. DC/RF dispersion tests showed MOS-HFETs with O3 oxidant had ~200 × better current collapse recovery. Temperature characterization and reliability test results, such as high-temperature reverse bias (HTRB), are published for the first time on ALD-HfO2/AlGaN/GaN MOS-HFETs using tetrakis(dimethylamino)hafnium (TDMAH) and O3 precursor. Using an ozone oxidant provided more stability (i.e., less variability in RON and VTH) as a function of temperature. Finally, when devices were electrically stressed in the OFF-state, the HTRB test showed minimal VTH drift (<0.5 V) in the case of O3 oxidant versus much larger VTH drift (2.5 V) in the case of H2O oxidant. [ABSTRACT FROM AUTHOR]

Objective: Medicinal plants have played a key role in the prevention and treatment of diseases since ancient period. They are also potential sources of drugs and nutrients. Boerhavia diffusa and Achyranthes aspera are widely used medicinal plants in Ayurvedic treatment for a variety of ailments including kidney diseases. The present study was designed to assess the free radical scavenging capacity of herbal formulated medicinal plants, B. diffusa and A. aspera. Materials and Methods: Ethanolic extracts of herbal formulation were prepared and evaluated for their free radical scavenging capacity using various in vitro chemical assays such as 2,2-diphenyl-1-picrylhydrazyl, 2,2'-azinobis(3-ethylbenzothiazolin-6-sulfonic acid), ferric reducing antioxidant power, hydroxyl radical, and superoxide anion radical scavenging activities. Results: The ethanolic extract of herbal formulation showed potential radical scavenging activity against the radicals generated in vitro as the result was compared with the standard at the same concentration. Conclusion: The present research concluded that herbal formulated medicinal plants, B. diffusa and A. aspera, were found to be more effective due to the combined activity of the individual components. Hence, it is concluded that herbal formulation of these plants may provide efficient, supportive, or alternative treatment procedures for numerous health ailments. [ABSTRACT FROM AUTHOR]

• A novel magnetic multi-amine decorated resin (MmAR-G) was newly prepared. • Extra hydroxyl was introduced to MmAR-G due to the epoxide-opening reaction. • MmAR-G showed excellent uptake for TC and Cu in sole solution. • High NaCl concentration inhibited TC but facilitated Cu2+ adsorption onto MmAR-G. • MmAR-G had maximum cumulative adsorption amount for TC and Cu in binary solution. A magnetic multi-amine decorated resin (MmAR-G) was prepared via polymerization, post-crosslinking, and amination reactions for adsorption and coadsorption of tetracycline (TC) and copper (Cu). The results showed that MmAR-G had relatively higher specific surface area, larger pore size, and abundant chelating groups (amino, carbonyl, and hydroxyl groups). Compare with other multi-amine resins, MmAR-G showed maximum uptake for both TC (0.104 mmol/g) and Cu2+ (0.385 mmol/g). The higher specific surface area and protonated amine led to higher TC adsorption capacity. The extra hydroxyl introduced by epoxide-opening reaction when amination, carboxyl, neutral and protonated amines can chelate with Cu2+ and enhance the adsorption, which was demonstrated by the XPS characterization. In the presence of NaCl, the competing adsorption of Cl−decreased the TC adsorption remarkably, and the restrain of the hydrogen bond formation provided more chelation groups and facilitated Cu2+ removal. In binary solutes systems, the formation of Cu-TC complexes decreased TC and Cu2+ adsorption onto MmAR-G by reducing the affinity. Still, the cumulative adsorption amount for TC and Cu2+ onto MmAR-G was highest (0.376 mmol/g). The results showed that MmAR-G was a promising adsorbent for remove and coremove organics and heavy metals in wastewater. [ABSTRACT FROM AUTHOR]

Experiments were performed at Summit, Greenland (72°34′ N, 38°29′ W) to investigate hydroxyl mixing ratios in the sunlit surface snowpack (or firn). We added a carefully selected mixture of hydrocarbon gases (with a wide range of hydroxyl reactivities) to a UV and visible light transparent flow chamber containing undisturbed natural firn. The relative decrease in mixing ratios of these gases allowed estimation of the lower limit mixing ratio of hydroxyl radicals in the near-surface firn pore spaces. Hydroxyl mixing ratios in the firn air followed a diurnal cycle in summer 2003 (10-12 July), with peak values of more than 3.2×106 molecules cm-3 between 13:00 and 16:00 local time. The minimum value estimated was 1.1×106 molecules cm-3 at 20:00 local time. Results during spring of 2004 showed lower, but rapidly increasing, peak hydroxyl mixing ratios of 1.1×106 molecules cm-3 in the early afternoon on 15 April and 1.5×106 molecules cm-3 on 1 May. Our firn hydroxyl estimates were similar to directly measured above-snow ambient levels during the spring field season, but were only about 30% of ambient levels during summer. © 2007 Elsevier Ltd. All rights reserved.

We investigate the interrelation between the hydration of the lunar regolith and the mineral composition of the surface of the Moon with respect to the concentrations of plagioclase, TiO2 (highly correlated with the oxide mineral ilmenite), and Mg-spinel. The spectral properties of lunar regions with a low concentration of plagioclase or a high concentration of TiO2 or Mg-spinel show a significant reduction in hydration at lunar midday compared to other compositions. This suggests that these oxide minerals contain less of the strongly bound OH component, which is not removed at lunar midday. The time-of-day-dependent variation of the 3 μm band depth is greater in TiO2-rich areas compared to other mare regions. The TiO2-rich regions therefore appear to have a strong tendency to adsorb solar wind-induced hydrogen into binding states of low energy that can more readily desorb and readsorb OH/H2O on a daily basis.

The hydroxyl of the gem-grade forsterite from Pakistan was measured by the polarized spectra at room temperature to 1000 °C, showing four unambiguous absorption bands at 3612, 3597, 3579, and 3566 cm−1. Here, we report angle-resolved polarized IR spectroscopy of the crystal-oriented forsterite, which were heated at 1 bar up to 1000 °C in situ to investigate the hydrogen diffusion character. The peak positions of the IR absorbance at 3579 cm−1, 3597 cm−1, and 3566 cm−1 of forsterite decreased linearly depending on the temperature, while the 3612 cm−1 is stable. We discuss that the dipole orientation of the hydroxyl is analyzed by a pleochroic scheme of the integrated absorbance vs. sample to polarizer angle. Our data suggest that the temperature effect cannot be ignored since the absorption coefficients and absorbance band positions of OH may alter.

Synthetic heterocyclic compounds have incredible potential against different diseases; pyridines, phenolic compounds and the derivatives of azo moiety have shown excellent antimicrobial, antiviral, antidiabetic, anti-melanogenic, anti-ulcer, anticancer, anti-mycobacterial, anti-inflammatory, DNA binding and chemosensing activities. In the present review, the above-mentioned activities of the nitrogen-containing heterocyclic compounds (pyridines), hydroxyl (phenols) and azo derivatives are discussed with reference to the minimum inhibitory concentration and structure–activity relationship, which clearly indicate that the presence of nitrogen in the phenyl ring; in addition, the hydroxyl substituent and the incorporation of a diazo group is crucial for the improved efficacies of the compounds in probing different diseases. The comparison was made with the reported drugs and new synthetic derivatives that showed recent therapeutic perspectives made in the last five years.

Inhibitors of carbonic anhydrase (CA) have been carried out in many therapeutic applications, especially antiglaucoma activity. In this study, we investigated some uracil derivatives (4–12) to inhibit human CA I (hCA I) and II (hCA II) isoenzymes. The KI values of the compounds 4–12 are in the range of 0.085–428 µM for hCA I and of 0.1715–645 µM against hCA II, respectively. It is concluded from the kinetic investigations, all compounds used in the study act as competitive inhibitors with substrate, 4-NPA. Uracil derivatives are emerging agents for the inhibiton of carbonic anhydrase which could be used in biomedicine.

Background: Natural products like flavonoids from the natural or synthetic origin are known to possess anticancer, antioxidant, anti-inflammatory activities. However, there is few/no experimental proof presently available regarding these. In the present study, hydroxy thiophene derivative of flavonoid was synthesized by Claisen–Schmidt reaction using grinding technique and evaluated for antioxidant activity. Objective: The present study was aimed to synthesize, characterize and evaluate the free radical scavenging antioxidant activity by using in-vitro assay methods. Methods: Synthesized compound was characterized on the basis of Fourier-Transform Infrared Spectroscopy (FTIR), proton Nuclear Magnetic Resonance (1H NMR),13 C NMR, Mass Spectroscopy (MS) and elemental analysis. The in vitro scavenging activity was studied on hydroxyl, nitric oxide radicals and superoxide anions. Further in the in vivo studies, the liver homogenate of diabetic mellitus rats induced by low dose streptozotocin fed on a high-fat diet, estimated for lipid peroxidase (TBARS), catalase(CAT), superoxide dismutase(SOD) activity and reduced glutathione (GSH) content by colorimetric assays. Results: The NF compound exhibited the dose-dependent free radical scavenging activity especially at 100mcg to 200mcg/ml concentration but lesser than that of standard drugs. Conclusions: The present study was demonstrated that the novel flavonoid (NF) found to have high antioxidant free radical scavenging activity against various oxidative stress systems which needs to be confirmed by other assays.

Effects of common ions, namely hydroxyl ions and carbonate, on the adsorption and flotation of malachite with salicylaldoxime as a collector was investigated, making use of solubility, micro-flotation, zeta potential, contact angle, FTIR, and XPS measurements. The results suggested that hydroxyl and carbonate ions affect malachite recovery through altering solubility of this mineral. Under conditions of lower solubility, more stable copper atoms acted as adsorption sites for retaining salicylaldoxime on the malachite surface, and the collector consumed by copper species in slurry was reduced. This allowed more collectors to get adsorbed onto malachite surface, resulting in improved malachite recovery. Zeta potential, FTIR, and XPS measurements indicated that salicylaldoxime chemically adsorbs onto malachite by forming copper salicylaldoxime chelates, in which two salicylaldoxime molecules react with one copper atom by N atom and the O atom combined with benzene ring. [ABSTRACT FROM AUTHOR]

At present, amino acids are often used as the source of heteroatom functional groups for the preparation of doped graphene materials. However, a large amount of amino acids will be used as reaction precursors in the preparation process, which will lead to increased cost, reduced efficiency and waste of resources. Herein, a very small amount of neutral l -alanine is employed to synthesize 3D carboxyl and hydroxyl co-enriched graphene hydrogels (CHGHs) by a one-pot hydrothermal method. The CHGHs contain copious carboxyl and hydroxyl groups, and a small amount of nitrogen-containing functional groups. In addition, the CHGHs also present large specific surface areas and 3D porous structures. Therefore, the CHGH-20 binder-free electrode displays a high specific capacitance of 262.8 F g−1 at 0.3 A g−1, and this value still maintains 84.3% (221.6 F g−1) at 10 A g−1 in a two-electrode system in 6 M KOH. Furthermore, the CHGH-20 electrode also displays outstanding cycle stability with 103.6% of its initial capacitance after 10,000 cycles at 10 Ag−1. Therefore, the CHGHs samples prepared by a very small amount of neutral l -alanine have great significance for the practical application of supercapacitors. Image 1 • CHGHs samples are easily prepared via a one-pot hydrothermal method. • CHGHs samples have 3D porous structures and high specific surface areas. • CHGHs samples have high content of carboxyl and hydroxyl groups. • The CHGH-20 based electrode shows a high specific capacitance of 262.8 F g−1. • The CHGH-20 based symmetric supercapacitor displays outstanding cycle stability. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) with abundant oxygen functional groups has been widely studied as friction-reduction additive in lubricating oil or directly as solid lubricant. However, the lubrication mechanisms of these groups in solid GO lubricants have not been well revealed yet. Herein, we report a new strategy to prepare hydroxyl-carboxyl-terminated GO, hydroxyl-terminated GO, less-hydroxyl-terminated GO, and reduced GO (rGO), and then employ them as a frictional research model to address this concern. The results reveal that a little amount of water confined in GO layers dominates the interlayer shearing resistance by confining hydrogen-bond interaction. The strongest confinement effect to hydrogen-bond is achieved in hydroxyl-terminated GO, leading to the lowest shearing resistance between GO layers and then the enhanced friction performances. This finding first reveals the synergistic lubrication mechanism of oxygen functional groups and confined interlayer water molecules, providing us a new design view to fabricate superior graphene-based solid lubrication materials. Unlabelled Image • A new strategy is proposed to optimize the oxygen functional groups on GO. • The optimized hydroxyl-terminated GO shows an ultralow friction coefficient. • The contribution of confined interlayer water is first reveled in GO lubricants. • The friction reduction comes from the weakened hydrogen-bond interaction. [ABSTRACT FROM AUTHOR]

Abstract The atmosphere of Jupiter is mainly hydrogen and methane, with a large number of hydrocarbons calculated to be produced by photodissociation and subsequent reactions. It is assumed that oxygen is added by meteoroids. Recent studies have found that photochemistry does not explain the measured ratios of water to carbon monoxide, if it is assumed that water is the major constituent of meteoroids and vapourises. A possible explanation is that processes that occur during or soon after the meteoroid's passage change the proportions of the oxygen-bearing constituents. In this paper, the processes considered are dissociation, ionization of the original molecules and ionization of dissociated products. The difference between applying these processes in the bulk atmosphere and in the meteor trail itself is investigated, as is the possibility of methane being dissociated in a shock wave produced by the meteoroid. In all cases, there was no significant change to the predicted density of water at the height of a measurement. However, the density of hydroxyl relative to water differed depending on the assumed process, thus presenting the possibility that measurements of electron-driven emissions from hydroxyl could be used for remote sensing of the actual processes occurring. Highlights • Densities of H 2 O, CO, CO 2 and OH, produced by meteoritic input, are calculated for the atmosphere of Jupiter. • Dissociation, ionization, and enhanced reaction rates in the meteor trails do not influence the densities at the height of a measurement. • The OH:H 2 O density ratio shows potential for remote sensing using electron-driven emissions. [ABSTRACT FROM AUTHOR]

The hydroxyl radical (OH) fuels tropospheric ozone production and governs the lifetime of methane and many other gases. Existing methods to quantify global OH are limited to annual and global-tohemispheric averages. Finer resolution is essential for isolating model deficiencies and building process-level understanding. In situ observations from the Atmospheric Tomography (ATom) mission demonstrate that remote tropospheric OH is tightly coupled to the production and loss of formaldehyde (HCHO), a major hydrocarbon oxidation product. Synthesis of this relationship with satellite-based HCHO retrievals and model-derived HCHO loss frequencies yields a map of total-column OH abundance throughout the remote troposphere (up to 70% of tropospheric mass) over the first two ATom missions (August 2016 and February 2017). This dataset offers unique insights on near-global oxidizing capacity. OH exhibits significant seasonality within individual hemispheres, but the domain mean concentration is nearly identical for both seasons (1.03 ± 0.25 × 106 cm-3), and the biseasonal average North/South Hemisphere ratio is 0.89 ± 0.06, consistent with a balance of OH sources and sinks across the remote troposphere. Regional phenomena are also highlighted, such as a 10- fold OH depression in the Tropical West Pacific and enhancements in the East Pacific and South Atlantic. This method is complementary to budget-based global OH constraints and can help elucidate the spatial and temporal variability of OH production and methane loss. [ABSTRACT FROM AUTHOR]

We used the DACAPO code with the GGA-PW91 approximation to study the adsorption of methyl (CH3) and hydroxyl (OH) for four- and five-layer gold (Au) (001) slabs. We have determined for each species the best binding site, adsorption energy, the change in the work function, surface energy, surface dipole moment, geometrical parameters and projected density of states (PDOS). We performed spin-unpolarized and spin-polarized DFT calculations for free and adsorbed CH3 and OH species. The most important point is that the spin polarization diminishes the adsorption energies but does not change the geometrical parameters. For the CH3 species, only the top site was found to be stable for different coverages. We found that during the optimization phase, the hollow and bridge sites were found to be unstable. In both cases the CH3 species moves toward the top site. We observe that the adsorption energy decreases when increasing the coverage. However, the OH species was stable in all investigated sites (top, bridge and hollow). We notice that the adsorption energy is dependent on the number of slab layers and the bridge is the best site in adsorption energy. The analysis of the calculated O PDOS of OH radical shows a mixing between the O orbitals and the Au bands. [ABSTRACT FROM AUTHOR]

We report here for the first time aluminous Ca-amphibole exsolution lamellae in an anhydrous chromite host of podiform chromitite from the Nakhl massif of the Semail Ophiolite. Transmission electron microscopy observations show that the Ca-amphibole lamellae have a crystallographic topotaxy and d -spacing relationship with the host chromite, i.e., [103] am //[11 8 _ ] chr , (020) am //(2 2 _ 0) chr and d 060am ≈ d 220chr , that indicate an exsolution origin. The presence of Ca-amphibole exsolution implies the incorporation of Si4+ and Ca2+ cations and hydroxyl in the host precursor chromite. The reconstructed precursor chromite had SiO 2 concentrations of 0.33–0.58 wt%, suggesting upwelling from a minimum pressure of 8 GPa (depth of ~250 km). Hydroxyl groups occupy octahedral vacancies, which can be introduced in high-pressure chromite by substituting 4 Cr3+ by 3 Si4+ and a vacancy. During upwelling, vacancies decrease when Si4+ cations exsolve stepwise from chromite. It leads to a coupled decrease of OH occupied vacancies and exsolution of Ca-amphibole lamellae at pressures below 3 GPa. Our results provide new evidence for a deep origin of the chromitite-bearing mantle section of the Semail ophiolite. • Aluminous Ca-amphibole exsolution lamellae are firstly found in chromite from Semail ophiolite. • The reconstructed precursor chromite indicates Oman podiform chromitite upwelling from a depth > 250 km. • Exsolved Ca-amphibole indicates OH can incorporate in chromite by Si4+ 3 / 1 Cr3+ −4 substitution in M site at HP condition. • Oman podiform chromitite from Semail ophiolite has a deep origin. [ABSTRACT FROM AUTHOR]

Abstract Cationic lipids can easily assemble into spherical liposomes in aqueous phase which showed unique superiority in drug and gene delivery. However, the toxicity of cationic lipids is still an obstacle to application. To develop low toxicity cationic lipids, we designed two cationic lipids contained different number of hydroxyl groups. Biocompatible mono-hydroxyl and multi-hydroxyl galactose head group was respectively modified to a biodegradable quaternary amine lipid, and two novel hydroxyl cationic lipids were synthesized and characterized by MS, 1H NMR and 13C NMR. Two lipids showed good surface activity and both of them can assemble to about 80 nm stable small unilamellar vesicles (SUVs) with cholesterol in aqueous phase. Both of lipids showed relatively lower toxicity than the well-known cationic lipid 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP). In vitro 24 h IC 50 of two assemblies were more than 50 μg/mL, which were about 10 μg/mL higher than the IC 50 of DOTAP. Multi-hydroxyl galactose lipids group showed much lower toxicity than mono-hydroxyl lipids group. Moreover, Both of the assemblies with lower hemolysis were nearly non-hemolytic risk under the concentration of 30 μg/mL. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) showed that the average sizes of both doxorubicin (DOX) loaded liposomes were about 110 nm. The DOX entrapment efficiencies of galactose liposome and mono-hydroxyl liposome were 58% and 91%, respectively. Both of the DOX loaded liposomes were stable after one month placed at room temperature. Two DOX loaded liposomes showed better anti-cancer effect than free DOX above 5 μg/mL, and they can be internalized into cells and produce more release of DOX inside MCF-7 cells and HepG2 cells at pH 5.0. These results suggested that synthesized lipids are suitable as potential low toxicity cationic drug delivery systems. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Hydroxyl decorated 0D g-C 3 N 4 NPs were synthesized via a simple hydrothermal method. • The NPs possess narrowed bandgap, increased surface area and better hydrophily than bulk g-C 3 N 4. • ZnS-g-C 3 N 4 photocatalysts present a high photocatalytic activity of 112 μmol h−1. • Theoretical calculations are carried out to explain the high photocatalytic activity. • A systematic investigation of photocatalytic mechanism is proposed. Abstract Zero-dimensional graphitic carbon nitride nanoparticles (0D g-C 3 N 4 NPs) possess the advantages of non-toxicity, metal-free, and rich surface catalytic active sites. However, the complex preparation process, wide bandgap structure, easily particle aggregation and rapid carriers' recombination still limit their development in photocatalysis. Herein, these issues are addressed by synthesizing a novel hydroxyl (-OH) modified g-C 3 N 4 NPs with a simple hydrothermal method without using any etching agents. Besides the high hydrophily and small particle size, the OH decorated 0D g-C 3 N 4 NPs possess obvious narrowed bandgap and high reduction potential. To further improve their dispersity and carriers' separation rate, 0D/3D g-C 3 N 4 NPs/ZnS type II heterojunction is fabricated, which simultaneously improves the hydrophily, passivates the surface defects and extends the sunlight absorption range of ZnS. As a result, a high and cyclable photocatalytic activity of 112 μmol h−1 (5.6 mmol h−1 g−1) is achieved under visible light irradiation without any co-catalysts, which is 140 times higher than that of pure ZnS and much better than the pure 0D g-C 3 N 4 NPs. A systematic study of photocatalytic mechanism is proposed by combining the theoretical calculations and experimental results. This work offers a new sight for the design of 0D g-C 3 N 4 NPs based photocatalysts for H 2 production. [ABSTRACT FROM AUTHOR]

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Highlights • Model of time-of-day-dependent lunar OH column density. • Consistency with observations across broad range of H diffusivity pre-factors. • Major importance of OH photolysis for time-of-day-dependent OH variations. • Minor importance of micrometeoroid-delivered OH/H 2 O for 3 µm band depth. • Probable presence of region-specific temporally constant stable OH component. Abstract In this study we determine the depth of the absorption band around 3 µm wavelength, which indicates the presence of OH/H 2 O in a thin surficial layer of the lunar regolith, for 18 lunar highland regions observed by the Moon Mineralogy Mapper (M3) instrument at 4–8 different local times of day. For removing the thermal emission component, a physically motivated thermal equilibrium based method is used, which also takes into account the roughness of the regolith surface. We propose a continuity equation based model of the time-of-day-dependent column densities of surficial atomic hydrogen (H) and hydroxyl (OH). The considered source processes for H are implantation of solar wind protons and photolysis of OH, and for OH the reaction H + O → OH. Sink processes are diffusive loss for H and OH, and photolysis for OH. Sputtering of H and OH is found to be negligible in comparison to the other sink processes. Additionally, we suggest a similar differential equation based model to describe the time-of-day-dependent behavior of micrometeoroid-delivered OH and H 2 O. The observed 3 µm band depth values indicate that the surficial OH/H 2 O does not vanish even at local midday at low latitudes, while the model predicts nearly complete removal of surficial OH/H 2 O at midday. This apparent contradiction between model and observations is reconciled by adding to the model a region-specific "offset" OH component which is assumed to be stable against diffusive loss and photolysis and is therefore interpreted as a strongly bounded OH component. Meteoroid bombardment is found to be negligible in comparison with the solar wind source of OH. Fitting the model to the observed 3 µm band depth values allows for estimating the H activation energy, the OH photolysis time, region-specific values of the offset OH component, and the proportionality factor between OH column density and 3 µm band depth. The observed time-of-day-dependent behavior of the 3 µm band depth at low and high latitudes can be explained convincingly by the modeled source and sink processes. The best-fit OH photolysis time is much shorter than the lunar day and corresponds to 1–3 times the gas-phase value, which indicates that photolysis is a mechanism of high relevance for the behavior of solar wind induced surficial OH. The surface roughness assumed in the M3 data analysis does not have a major influence on the modeling results. The strongly bounded OH component is nearly latitude-independent for low latitudes but decreases sharply for high latitudes. As a possible mode of origin, we suggest slow diffusion of solar wind induced OH to depths inaccessible for ultraviolet photons and into binding states of higher energy, counteracted by sputtering. [ABSTRACT FROM AUTHOR]

Locations used to validate extraction results from remote sensing images are typically ground rock samples. However, remotely sensed image pixels are 30 m2 with mixing spectra. Rock samples cannot fully represent extraction results on an image. Here, alteration information associated with the Águas Claras, Brazil iron deposit was analysed using a Landsat Enhanced Thematic Mapper plus (ETM+), a Terra Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Hyperion data, all with 30 m resolution. With improvements in spectral resolution, extracted results have changed from the alteration information to altered rocks and minerals. The accuracy of alteration information has improved continuously as data extracted from these sources verify one another. Minerals extracted using Hyperion corresponded to altered assemblages identified from ASTER. Both were consistent with alteration information extracted from ETM+ at the same location. Alteration information extracted from three remote images were located within ore formations, and controlled by the north‐east trending faults and matched well with known deposits. Information extraction based on the integrated application of multi‐source remote sensing data could compensate for deficiencies in using single data. These results can verify one another to improve data reliability particularly in the areas inaccessible and lacking sufficient field confirmation. [ABSTRACT FROM AUTHOR]

Highlights • Identified a solubilization maximum at 60 wt% ethanol. • The molar mass distribution of the fractions can be adjusted by the solvent's ethanol concentration. • The phenolic hydroxyls in lignin can be concentrated by removing the water-soluble fraction. • The phenolic hydroxyls in lignin can be concentrated by removing the ethanol-insoluble fraction. Abstract Lignin solubility is a varying property, as depending on the type of lignin and its origin, its solubility in different solvents will differ. This is due to the highly heterogeneous nature of lignin. Solubilizing lignin could improve its potential valorization by making it more conducive to chemical reactions. Solvent fractionation could be utilized as the first step in lignin refining to adjust some of its properties before further processing. It is known that kraft lignin is completely soluble in alkaline solvents such as aqueous NaOH. The purpose of this study was to assess the solubility of Indulin AT lignin in aqueous ethanol solvents and to determine the useful properties of the resulting fractions: namely, molar mass distribution and phenolic hydroxyl groups. The highest concentration of lignin was achieved in 60 wt% ethanol solution with 235.89 g/L at a solid-to-liquid ratio of 300 g Lignin /L Solvent. The original lignin had a mass average molar mass of 4.7 kDa. When only water was utilized, the average molar mass of the dissolved fraction was between 1 and 2 kDa and the molecular size distribution was mostly between 0.1 and 1 kDa. When using pure ethanol, the molecular size distribution ranged from 0.1 kDa to 10 kDa, with a mass average molar mass between 1 and 1.3 kDa. With an ethanol content in the solvent higher than 90 wt%, the bigger molar mass molecules (>10 kDa) could be separated as the insoluble fraction. Additionally, the polydispersity of both fractions decreased with an ethanol concentration above 80 wt%. The hydroxyl group content of the insoluble fraction was higher when fractionating with less than 20 wt% ethanol, whereas with 20 wt% ethanol and higher, the soluble fraction retained most of the phenolic hydroxyls. Fractionating lignin prior to use or further processing may be potentially beneficial if the lower molar mass molecules can be used as they are, leaving only the higher molar mass molecules to be further processed or burned for energy. [ABSTRACT FROM AUTHOR]

Abstract In this work, we investigated the self-reaction of allyl radicals and its cross-reaction with hydroxyl radical by employing shock tube and laser absorption techniques. We carried out the experiments behind reflected shock waves over the temperature range of 800–1200 K and pressures of 1.1–2.5 bar. We generated allyl (C 3 H 5) and OH radicals by fast thermal decomposition of allyl iodide (C 3 H 5 I) and tert -butyl hydroperoxide (TBHP), respectively, and monitored reaction progress by detecting OH near 306.69 nm and C 3 H 5 near 220 nm using UV laser absorption. At the detection wavelength, we measured the temperature dependence of the absorption cross-sections of C 3 H 5 and C 3 H 5 I. Rate coefficient for the self-recombination reaction of allyl radicals showed a small negative temperature dependence and no noticeable fall-off behavior over 1.15–1.96 bar giving a mean value of k C 3 H 5 + C 3 H 5 = (1.0 ± 0.2) × 10 − 11 c m 3 molecul e − 1 s − 1 . Likewise, the cross-reaction of allyl and OH radicals did not exhibit discernible pressure and temperature dependence under our experimental conditions indicating a barrierless reaction, and an average value of k C 3 H 5 + OH = (9.3 ± 0.7) × 10 − 11 c m 3 molecul e − 1 s − 1 best illustrates our measured rate coefficients. These measurements represent the first direct experimental determinations of the rate coefficients for these important radical-radical reactions at high temperatures and pressures. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydroxyl and sulfate radicals-induced IMI degradation was theoretically probed. • Initial HA reactions occurring on alkylamine side chain of IMI are the most favorable. • Ring-opening reactions for benzene ring and seven-membered N -heterocycle occur hardly. • Stronger oxidizing ability was found for SO 4 •− compared with •OH in IMI degradation. • H 2 O and O 2 molecules exhibit significant influences over aqueous degradation of IMI. In the present work, hydroxyl (•OH) and sulfate radicals (SO 4 •−)-induced aqueous degradation of imipramine (IMI) was theoretically probed by carrying out density functional theory (DFT) calculation. Among the initial reactions of •OH (SO 4 •−) toward IMI, the hydrogen abstraction (HA) reactions occurring on saturated carbon atoms of the alkylamine side chain are the most favorable, followed by the addition (AD) reactions involving unsaturated carbon positions, and the HA reactions related to unsaturated carbon atoms are the most unfavorable. The most favorable subsequent reactions for the initial AD and HA intermediates can afford the hydroxylation, oxidation, dehydrogenation, C N or C C bond cleavage products of IMI, while the corresponding ring-opening reactions occur hard. The stronger oxidizing ability of SO 4 •− was predicted in comparison with •OH. The cationic form of IMI has lower reactivity than IMI.H 2 O and O 2 molecules may exert a significant influence over aqueous degradation of IMI. [ABSTRACT FROM AUTHOR]

The effect of chemical solvents on the wetting state of laser-structured surfaces over time is systematically examined in this paper. By using a 300-fs laser, nanostructures were generated on Ti6Al4V, subsequently cleaned in an ultrasonic bath with different solvents and stored in ambient air. The static contact angle showed significant differences for cleaning with various solvents, which, depending on the applied cleaning and time, amounted up to 100°. X-ray photoelectron spectroscopy analyses reveal that the cleaning of the laser-structured surfaces affects the surface chemistry and the aging behavior of the surfaces, even with highly volatile solvents. The effect of the chemical surface modification is particularly noticeable when using alcohols for cleaning, which, due to their OH groups, cause highly hydrophilic behavior of the surface after one day of storage. Over the course of 14 days, enrichment with organic groups from the atmosphere occurs on the surface, which leads to poorer wetting on almost every structured surface. In contrast, the cleaning in hexane leads to a fast saturation of the surface with long-chain carbon groups and thus to a time-independent hydrophobic behavior.

The concept of oxidative stress, the factors responsible for oxidative stress and on those substances in foods that may have in vivo effects in terms of decreasing the adverse effects of reactive oxygen species (ROS) and reactive nitrogen species (RNS) on normal physiological function are reviewed. Methods of analysis of dietary redox reactive compounds and the role of dietary antioxidants in preventing disease are discussed. Literature related to the role of consumption of dietary bioactives (antioxidants) on the prevention of adverse health outcomes, with clinical trials in human subjects as the primary focus is reviewed.

Abstract: All major, rock-forming lower-mantle minerals (bridgmanite, CaSi-perovskite, ferropericlase and stishovite) are "nominally anhydrous minerals" (NAMs), in which hydrogen comprises less than 1 wt % and whose chemical formula would be normally written without hydrogen. In NAMs, hydrogen occupies various defects of the crystal lattice and is bonded to structural oxygen, forming hydroxyl groups. Currently, two main techniques can be used for water determination in the mantle minerals: Fourier transform infrared spectrometry (FTIR) and secondary ion mass spectrometry (SIMS). They produce different results: determinations by SIMS are usually higher than quantifications of FTIR. As a result, the estimates of water concentrations in lower-mantle minerals vary widely. Most reliable concentrations of water are 1400-1800 ppm in bridgmanite, 10-80 ppm in ferropericlase, and 20-150 ppm in stishovite. The average concentration of water in the lower mantle is ~1500 ppm. Despite such minor concentrations in lower-mantle minerals, water forms a great reservoir within the lower mantle, probably amounting ~45.45 × 1023 grams H2O, i.e., ~3.3 times the mass of the Earth's oceans. Some amount of water is transported into the lower mantle by subducting lithospheric slabs; this amount is balanced by the water flux from the lower mantle to the transition zone. Within areas of partial melting in the lower and upper parts of the lower mantle, as well as in some local areas, stress and thermal increase initiate release of water from lower-mantle minerals into melt. The enrichment of partial melts with H2O depends on the P-T conditions, oxygen fugacity values, and percentage of melting. It causes major geodynamic processes that are initiated within the deep Earth. The major source of the water reservoir in the lower mantle is primordial water stored early in the Earth's evolution. [ABSTRACT FROM AUTHOR]

Highlights • Measured collisional lineshape parameters of a Hydroxyl radical UV transition. • Voigt lineshape model maintains validity at pressures up to 95 atm. • Improved range and accuracy of laser absorption diagnsotic for combustion studies. Abstract The collision-induced broadening (2γ OH A) and shift (δ OH A) parameters of hydroxyl radical (OH) with two collisional partners—argon and nitrogen—and their associated temperature-dependence coefficients (n A and m A , respectively), have been measured in a series of shock tube experiments. The Q 1 (5) OH transition, a member of the A2Σ – X2Π (0, 0) rovibronic band with a line-center wavelength near 308.6 nm, represents an ideal target for quantitative spectroscopy in combustion applications, owing to its strength and degree of relative spectral isolation. Narrow-width tunable UV light was used to sample the Q 1 (5) lineshape profile across 8–10 wavelengths. The data were subsequently fit to the Voigt lineshape model at the fixed temperature, pressure and mixture composition. Measurements are presented for 2γ OH Ar, δ OH Ar , n Ar , and m Ar , recommended for T = 1300–2000 K, as well as 2γ OH N2, δ OH N2, n N2 , and m N2 , recommended for T = 1600–2000 K. The Q 1 (5) lineshape was also measured at pressures of 45 and 95 atm, for which application of the Voigt model yielded values of 2γ OH Ar and δ OH Ar that were consistent with lower-pressure measurements, supporting the validity of the lineshape model and, particularly, the diagnostic in question at such pressures. [ABSTRACT FROM AUTHOR]

Development of supported noble metal catalysts with ultralow noble metal loading, commercially available support with good stability and low cost, as well as facial synthesis route for indoor HCHO removal at room temperature is desirable. Herein, enhanced HCHO oxidation performance over Pt/ZSM-5 is achieved through a facile nickel cation modification. The introduction of a proper amount of nickel cations enhances nearby hydroxyl density around the Pt active sites and leads to great enhancement in HCHO oxidation activity. Pt-Ni/ZSM-5 exhibits a 90% HCHO conversion and a 100 h good stability at 30 °C with a low 0.1 wt% Pt amount and ultralow 0.05 wt% Ni addition, an initial 50 ppm HCHO and space velocity of 30000 mL h −1  g −1 , which is among the best of the state-of-the-art Pt-based catalysts in consideration with Pt utilization efficiency. The facile ionic exchange approach employed in this study provides an important implication into the design of economic zeolite based catalysts for HCHO removal and other hydroxyls related reactions. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Jilin University (Science Edition) / Jilin Daxue Xuebao (Lixue Ban) is the property of Zhongguo Xue shu qi Kan (Guang Pan Ban) Dian zi Za zhi She and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)