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In this paper, statistical analysis and experimental methods are employed to study the hydrobromination of hydroxyl-terminated polybutadiene (HTPB) elastomer by 48% hydrobromic acid. The effect of three variables including time, temperature, and volume of acid, on the percentage of hydrobromination is investigated. The influence of these parameters and their interaction is checked through the analysis of variance and sensitivity analysis, and the optimum values for 10% hydrobromination are obtained 24 h, 30 °C, and 5.05 ml of the acid volume. A hydrobrominated resin is synthesized by applying optimal conditions for hydrobromination of 10% of double bonds. The results obtained from classical analysis and NMR show the amount of hydrobromination as 9.89% and 9.38%, respectively. The placement of the bromine atom in the compound is confirmed by ATR and NMR analysis. Also, DSC analysis shows that the glass transition temperature (Tg) of the hydrobrominated product increased by 2.86 °C compared to the initial HTPB. [ABSTRACT FROM AUTHOR]

Here, we analyzed the performance of a hydrogen/bromate fuel cell (HBFC) operating in batch recirculation mode. We adjusted the catholyte composition and operating conditions to ensure stable cell discharging and prevent the formation of liquid bromine. To achieve this, we analyzed the evolution of bromate catholytes with different acid content using thermodynamic calculations, which considered equilibria between bromine compounds and material balance for protons. We used the results of these calculations and data on catholyte chemical stability to select compositions appropriate for HBFC testing. To obtain data on catholyte evolution, we employed novel spectrophotometric and electrochemical in situ/operando techniques. Our study revealed that the composition of the catholyte and its average oxidation state, as well as the interplay between chemical and electrochemical reactions, significantly impact the power output of the HBFC. The main practical finding of our study is that under optimized conditions, the HBFC demonstrated both high energy density and reasonable performance. For instance, with a catholyte composition of 1 M LiBrO 3 and 0.3 M H 2 SO 4 , energy density is 116 Wh L−1 (theoretical 1270 Wh L−1 for 5.5 M LiBrO 3) the cell operated with 98.7% capacity utilization and power of 194 mW cm−2 at 250 mA cm−2. • Operation of H 2 /BrO 3 fuel cell in batch recirculation mode is studied. • Catholyte composition during device discharge measured by in-situ methods. • Main components of acidic bromate catholyte are BrO 3 −, Br 2 , Br−, and Br 3 − • Interplay between chemical and electrochemical reactions determines power output. • CU of H 2 /BrO 3 fuel cell reaches up to 98.7 % at 250 mA cm−2 [ABSTRACT FROM AUTHOR]

Bromine activation (the production of Br in an elevated oxidation state) promotes ozone destruction and mercury removal in the global troposphere and commonly occurs in both springtime polar boundary layers, often accompanied by nearly complete ozone destruction. The chemistry and budget of active bromine compounds (e.g., Br2 , BrCl , BrO , HOBr) reflect the cycling of Br and affect its environmental impact. Cyanogen bromide (BrCN) has recently been measured by iodide ion high-resolution time-of-flight mass spectrometry (I- CIMS), and trifluoro methoxide ion time-of-flight mass spectrometry (CF3O- CIMS) during the NASA Atmospheric Tomography Mission second, third, and fourth deployments (NASA ATom), and could be a previously unquantified participant in active Br chemistry. BrCN mixing ratios ranged from below the detection limit (1.5 pptv) up to as high as 36 pptv (10 s average) and enhancements were almost exclusively confined to the polar boundary layers in the Arctic winter and in both polar regions during spring and fall. The coincidence of BrCN with active Br chemistry (often observable BrO , BrCl and O3 loss) and high CHBr3/CH2Br2 ratios imply that much of the observed BrCN is from atmospheric Br chemistry rather than a biogenic source. Likely BrCN formation pathways involve the heterogeneous reactions of active Br (Br2 , HOBr) with reduced nitrogen compounds, for example hydrogen cyanide (HCN / CN-), on snow, ice, or particle surfaces. Competitive reaction calculations of HOBr reactions with Cl- / Br- and HCN / CN- in solution, as well as box model calculations with bromine chemistry, confirm the viability of this formation channel and show a distinct pH dependence, with BrCN formation favored at higher pH values. Gas-phase loss processes of BrCN due to reaction with radical species are likely quite slow and photolysis is known to be relatively slow (BrCN lifetime of ∼ 4 months in midlatitude summer). These features, and the lack of BrCN enhancements above the polar boundary layer, imply that surface reactions must be the major loss processes. The fate of BrCN determines whether BrCN production fuels or terminates bromine activation. BrCN reactions with other halogens (Br- , HOCl , HOBr) may perpetuate the active Br cycle; however, preliminary laboratory experiments showed that BrCN did not react with aqueous bromide ion (< 0.1 %) to reform Br2. Liquid-phase reactions of BrCN are more likely to convert Br to bromide (Br-) or form a C – Br bonded organic species, as these are the known condensed-phase reactions of BrCN and would therefore constitute a loss of atmospheric active Br. Thus, further study of the chemistry of BrCN will be important for diagnosing polar Br cycling. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis of the solid solutions of 1D lead-free halide perovskites, (C2H5NH3)2BiCl5−xBrx (x = 0–5), using a solution method. All the synthesized compounds adopt the orthorhombic Cmca space group at room temperature (RT) (293 K) and undergo a phase transition to a low symmetry orthorhombic space group, Aba2, at a low temperature (LT) of 90 K. All the structures contain BiX6 (X = Cl or Br) corner-sharing polyhedra, forming zigzag 1D chains. The symmetry breaking phase transition from Cmca (293 K) to Aba2 (90 K) is due to the ordering of the ethylamine (removal of mirror plane) unit caused by strong H-bond formation in the low-temperature phase (LT phase). The TGA analysis indicates that (EA)2BiCl5 (EA = C2H5NH3+) is less stable than its bromine analogue. Optical studies show that all the compounds are of indirect band gap type with a band gap of 3 eV for the pristine chlorine compound and 2.5 eV for the pristine bromine compound. The band gap value gradually decreases with the incorporation of bromine at the chlorine site, following Vegard's law. According to the dielectric measurement, the pristine chlorine compound (x = 0) has a dielectric constant (εr) of 530, whereas that of the pristine bromine compound (x = 5) is 106 at room temperature and 10 kHz frequency. [ABSTRACT FROM AUTHOR]

The Z-scan instrument was used to study the nonlinear optical (NLO) properties of the derivatives of 3,3′-biindole 2,2′(1H,1′H)-dione, with different substitutions such as bromine, methyl, and phenyl groups. Specifically, the nonlinear absorption coefficient, β, nonlinear refraction index, n 2 , have been extracted and reverse saturation absorption and self-defocusing phenomena were investigated. It is observed that the presence of bromine in the compound structure can reduce the NLO properties. The reduction of dipole moment with bromine substitutions in the compound structure was confirmed with the quantum calculation. The NLO properties of the biindole derivatives related to the thermo-optic coefficient and dipole moment of the compound. Overall, our findings indicate that the biindole derivatives are promising candidates for NLO absorption materials. [ABSTRACT FROM AUTHOR]

A series of new ethyl 7-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylates and their halogenated derivatives were synthesized. Ethyl 7-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylate (2) was obtained by the condensation of 2-amino-4-hydroxybenzaldehyde and diethyl malonate. Halogenation of compound 2 with bromine led to the formation of 6,8-dibromo derivative 5, and the acylation and alkylation of 2 and 5 with acetic anhydride and p-chlorophenacyl bromide gave the corresponding acetoxy derivatives 3 and 6 and alkoxy derivatives 4 and 7. Compounds 2–7 were evaluated for their in vitro antiproliferative activity against MCF-7 and HepG2 cancer cell lines. The cell cycle analysis of compound 4 demonstrated cell cycle arrest at the G2/M phase and pre-G1 apoptosis. [ABSTRACT FROM AUTHOR]

The presence of reactive bromine in polar regions is a widespread phenomenon that plays an important role in the photochemistry of the Arctic and Antarctic lower troposphere, including the destruction of ozone, the disturbance of radical cycles, and the oxidation of gaseous elemental mercury. The chemical mechanisms leading to the heterogeneous release of gaseous bromine compounds from saline surfaces are in principle well understood. There are, however, substantial uncertainties about the contribution of different potential sources to the release of reactive bromine, such as sea ice, brine, aerosols, and the snow surface, as well as about the seasonal and diurnal variation and the vertical distribution of reactive bromine. Here we use continuous long-term measurements of the vertical distribution of bromine monoxide (BrO) and aerosols at the two Antarctic sites Neumayer (NM) and Arrival Heights (AH), covering the periods of 2003–2021 and 2012–2021, respectively, to investigate how chemical and physical parameters affect the abundance of BrO. We find the strongest correlation between BrO and aerosol extinction (R=0.56 for NM and R=0.28 for AH during spring), suggesting that the heterogeneous release of Br2 from saline airborne particles (blowing snow and aerosols) is a dominant source for reactive bromine. Positive correlations between BrO and contact time of air masses, both with sea ice and the Antarctic ice sheet, suggest that reactive bromine is not only emitted by the sea ice surface but by the snowpack on the ice shelf and in the coastal regions of Antarctica. In addition, the open ocean appears to represent a source for reactive bromine during late summer and autumn when the sea ice extent is at its minimum. A source–receptor analysis based on back trajectories and sea ice maps shows that main source regions for BrO at NM are the Weddell Sea and the Filchner–Ronne Ice Shelf, as well as coastal polynyas where sea ice is newly formed. A strong morning peak in BrO frequently occurring during summer and that is particularly strong during autumn suggests a night-time build-up of Br2 by heterogeneous reaction of ozone on the saline snowpack in the vicinity of the measurement sites. We furthermore show that BrO can be sustained for at least 3 d while travelling across the Antarctic continent in the absence of any saline surfaces that could serve as a source for reactive bromine. [ABSTRACT FROM AUTHOR]

This work presents macroscopic fibers of aligned double-walled carbon nanotubes (DWCNTs) intercalated with long-range ordered bromine, with a stoichiometry close to C 17 Br. Tribromide ions lie inside interstitial sites between hexagonally-packed DWCNTs and extend parallel to their axis as ordered supramolecular "wires". First-principles simulations confirm this structure and a transfer of 0.13 electrons per Br atom. The structure of nested bundles of CNTs with a homogeneous distribution of bromine species in the interstitial sites of the superlattice is directly imaged by cross-sectional HRTEM, showing full intercalation of highly dense and aligned fibers. The presence of Br 2 and B r 3 – is confirmed by Raman spectroscopy, and their supramolecular organization is resolved by 2D wide-angle X-ray scattering. Intercalation increases room-temperature longitudinal electrical conductivity by a factor of 8.4. Through low-temperature transport measurements in the longitudinal and transverse directions, we show that the intercalate reduces the tunneling-dominated resistance associated with transport between adjacent CNTs, rather than exclusively acting as a dopant that increases conductance of individual CNTs. By preserving the separation between CNTs, the exceptional mechanical properties of the CNT fiber host are retained. The combined tensile strength above 2.46 GPa and conductivity of 10.68 MS/m makes intercalated CNT fibers attractive lightweight conductors with combined properties superior to metals and graphite intercalation compounds. [Display omitted] [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Inorganic Analytical Chemistry / Zhongguo Wuji Fenxi Huaxue is the property of Beijing Research Institute of Mining & Metallurgy Technology Group 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.)

Different bromine compounds have found numerous applications. Nevertheless, there is still insufficient information about environmental chemistry of this trace element. In our research, a greenhouse pot experiment was carried out with the following aims: (1) to study the response of wheat and pea seedlings to an increase of concentrations two bromides (KBr and NaBr) in soil, (2) to assess the influence of root exudates of the two plant species on uptake of Br and some other macro- and trace elements when wheat and pea grow close to each other or far apart, and (3) to estimate possible allelopathic effects on the uptake of different elements by plants and also on the concentrations of polycyclic aromatic hydrocarbons in uncontaminated soil and in the soil contaminated by bromides. Both plant species were capable of accumulating large amounts of bromine. The concentration of bromine in roots of pea was higher than in wheat roots, and was always higher in leaves of wheat than in leaves of pea. More bromine was accumulated in roots of wheat and pea seedlings growing separately than in roots of the seedlings grown close to each other. Growth of wheat and pea seedlings in uncontaminated and spiked with bromides soils resulted in decrease of the concentrations of some polycyclic aromatic hydrocarbons in the rhizosphere soil of the plants. The variations depended on the plant species and were different when the plants were grown close to each other and separately. [ABSTRACT FROM AUTHOR]

Hypervalent compounds play a prominent role in homogeneous oxidation catalysis. Despite the higher reactivity of hypervalent bromine compounds when compared to their isoelectronic iodine analogues, the corresponding λ3-bromanes are much less explored. This can be attributed to the discernible lack of convenient strategies for their synthesis. This short review highlights the available methods for the synthesis of various organo-λ3-bromanes, with a major focus on the recent developments and reactivities in the last few years. Additionally, limitations and future prospects of hypervalent bromine chemistry are discussed. 1 Introduction 2 Diaryl-λ3-bromanes 3 Dialkyl-λ3-bromanes 4 Dihetero-λ3-bromanes 5 Alkenyl-λ3-bromanes 6 Alkynyl-λ3-bromanes 7 Conclusion and Prospects [ABSTRACT FROM AUTHOR]

Copyright of Nachrichten aus der Chemie is the property of Wiley-Blackwell 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.)

Radical halogen oxide species play important roles within atmospheric processes, specifically those responsible for the removal of O3. To facilitate future investigations on this family of compounds, RCCSD(T)/aug-cc-pVQZ-level electronic structure calculations were employed to generate individual-molecule optimized geometries, as well as to determine the global minimum energy structure for the BrO·H2O complex. This information facilitated the generation of several one-dimensional potential energy surface (PES) scans for the BrO·H2O complex. Scans were performed for both the ground state and the first excited state; this inclusion is due to a low-lying first electronic excited-state energy. These rigid-geometry PES scans were used both to generate a novel analytic interaction potential by modifying the existing Thole-type model used for water and to the fitted potential function. This interaction potential features anisotropic atomic polarizabilities facilitating appropriate modeling of the physics regarding the unpaired electron residing within the p-orbitals of the oxygen atom of the bromine oxide radical. The intention of this work is to facilitate future molecular dynamics simulations involving the interaction between the BrO radical and water clusters as a first step in devising possible novel chemistries taking place at the water interface of clouds within the atmosphere. [ABSTRACT FROM AUTHOR]

Nanocomposite polymer films are prepared by using ultrasonic spray deposition (USD) technique through mixing polymethyl methacrylate as matrix and fumed silica nanoparticles as second phase in dimethyl carbonate solvent. Annealing procedure improves the film uniformity and optical transmission. The addition of fumed silica nanoparticles impedes the transmission of the electrolyte films due to agglomeration of fumed silica nanoparticles. Fortunately, adding surfactant, cetyltrimethylammonium bromide, disperses the fumed silica nanoparticles and retrieves the optical transmission of nanocomposite polymer films to around 90%. The hardness and elastic modulus of the nanocomposite polymer films are better than the commercial bulk. The USD deposited nanocomposite polymer film comprises of PMMA and fumed silica nanoparticles is a promising candidate of solid-state electrolyte for EC windows application., INTRODUCTION Solid-state polymer film is an important component in systems like electrochemical devices. They are promising candidates as solid polymer electrolytes for lithium batteries and electrochromic (EC) devices after adding [...]

A new series of hybrid 2-quinolinone derivatives were synthesized by using 7-hydroxy-4-methyl- 1-amino-quinolin-2-one (2) and cinnamic acid. Hybrid halogenated 2-quinolinone derivatives (3-(7-hydroxy-4-methyl-3,6,8-tribromo-2-oxo-2H-quinolin-1-ylamino)-3-phenyl acrylic acid (4) and 3-(7-acetoxy-4-methyl-3,6,8-tribromo-2-oxo-1H-quinolin-1-ylamino)-3-phenyl acrylic acid (7)) were prepared via the halogenation of 3-(7-hydroxy-4-methyl-2-oxo-2H-quinolin-1-ylamino)-3-phenyl acrylic acid (3) with bromine to give compound 4 with acetic anhydride led to the formation of hydride halogenated 2-quinolinone derivative (7). All the synthesized hybrid 2-quinolinone and hybrid halogenated 2-quinolinone derivatives were tested for their cytotoxicity against MCF-7 cell line. DNA flow cytometric analysis of compounds 3 showed cell cycle arrest at G2/M phase with concomitant increase of cells in apoptotic phase. Dual annexin-V/propidium iodide staining assay of compound 3 revealed that, the selected molecule increases the apoptosis of MCF-7 cells more than control. [ABSTRACT FROM AUTHOR]

Photoelectron detachment XLX−(0000) + hν → XLX(vib) + e− + KER (X = Br or I, L = H or D) at sufficiently low temperatures photoionizes linear dihalogen anions XLX− in the vibrational ground state (v1v2lv3 = 0000) and prepares the neutral radicals XLX(vib) in vibrational states (vib). At the same time, part of the photon energy (hν) is converted into kinetic energy release (KER) of the electron [R. B. Metz, S. E. Bradforth, and D. M. Neumark, Adv. Chem. Phys. 81, 1 (1992)]. The process may be described approximately in terms of a Franck-Condon type transfer of the vibrational wavefunction representing XLX−(0000) from the domain close to the minimum of its potential energy surface (PES) to the domain close to the linear transition state of the PES of the neutral XLX. As a consequence, prominent peaks of the photoelectron detachment spectra (pds) correlate with the vibrational energies EXLX,vib of states XLX(vib) which are centered at linear transition state. The corresponding vibrational quantum numbers may be labeled vib = (v1v2lv3) = (000v3). Accordingly, the related most prominent peaks in the pds are labeled v3. We construct a model PES which mimics the “true” PES in the domain of transition state such that it supports vibrational states with energies EXLX,pds,000v3 close to the peaks of the pds labeled v3 = 0, 2, and 4. Subsequently, the same model PES is also used to calculate approximate values of the energies EXMuX,0000 of the isotopomers XMuX(0000). For the heavy isotopomers XHX and XDX, it turns out that all energies EXLX,000v3 are above the threshold for dissociation, which means that all heavy XLX(000v3) with wavefunctions centered at the transition state are unstable resonances with finite lifetimes. Turning the table, bound states of the heavy XLX are van der Waals (vdW) bonded. In contrast, the energies EXMuX,0000 of the light isotopomers XMuX(0000) are below the threshold for dissociation, with wavefunctions centered at the transition state. This means that XMuX(0000) are vibrationally bonded. This implies a fundamental change of the nature of chemical bonding, from vdW bonding of the heavy XHX, XDX to vibrational bonding of XMuX. For BrMuBr, the present results derived from experimental pds of BrHBr− and BrDBr− confirm the recent discovery of vibrational bonding based on quantum chemical ab initio calculations [D. G. Fleming, J. Manz, K. Sato, and T. Takayanagi, Angew. Chem., Int. Ed. 53, 13706 (2014)]. The extension from BrLBr to ILI means the discovery of a new example of vibrational bonding. These empirical results for the vibrational bonding of IMuI, derived from the photoelectron spectra of IHI− and IDI−, are supported by ab initio simulations of the spectra and of the wavefunction representing vibrational bonding of IMuI. [ABSTRACT FROM AUTHOR]

Collisions between potassium ions and neutral i-C3H7Br and i-C3H7OH, all in their electronic ground state, have been studied in the 0.10-10.00 eV center of mass (CM) collision energy range, using the radiofrequency-guided ion beam technique. In K+ + i-C3H7Br collisions KHBr+ formation was observed and quantified, while the analogous KH2O+ formation in K+ + i-C3H7OH was hardly detected. Moreover, formation of the ion-molecule adducts and their decomposition leading to C3H7 + and either KBr or KOH, respectively, have been observed. For all these processes, absolute cross-sections were measured as a function of the CM collision energy. Ab initio structure calculations at the MP2 level have given information about the potential energy surfaces (PESs) involved. In these, different stationary points have been characterized using the reaction coordinate method, their connectivity being ensured by using the intrinsic-reaction-coordinate method. From the measured excitation function for KHBr+ formation the corresponding thermal rate constant at 303 K has been calculated. The topology of the calculated PESs allows an interpretation of the main features of the reaction dynamics of both systems, and in particular evidence the important role played by the potential energy wells in controlling the reactivity for the different reaction channels. [ABSTRACT FROM AUTHOR]

In the Arctic winter/spring of 2019/2020, stratospheric temperatures were exceptionally low until early April and the polar vortex was very stable. As a consequence, significant chemical ozone depletion occurred in the Arctic polar vortex in spring 2020. Here, we present simulations using the Chemical Lagrangian Model of the Stratosphere that address the development of chlorine compounds and ozone in the Arctic stratosphere in 2020. The simulation reproduces relevant observations of ozone and chlorine compounds, as shown by comparisons with data from the Microwave Limb Sounder, Atmospheric Chemistry Experiment‐Fourier Transform Spectrometer, balloon‐borne ozone sondes, and the Ozone Monitoring Instrument. Although the concentration of chlorine and bromine compounds in the polar stratosphere has decreased by more than 10% compared to peak values around the year 2000, the meteorological conditions in winter/spring 2019/2020 caused unprecedented ozone depletion. The lowest simulated ozone mixing ratio was about 40 ppbv. Because extremely low ozone mixing ratios were reached in the lower polar stratosphere, chlorine deactivation into HCl occurred as is normally observed in the Antarctic polar vortex. The depletion in partial column ozone in the lower stratosphere (potential temperature from 350 to 600 K, corresponding to about 12–24 km) in the vortex core was calculated to reach 143 Dobson Units, which is more than the ozone loss in 2011 and 2016, the years which —until 2020— had seen the largest Arctic ozone depletion on record. Plain Language Summary: In Arctic winter and spring 2019/2020, the stratospheric temperatures were exceptionally low for a long time period. This caused an unprecedented Arctic ozone depletion. We show simulations that represent this ozone depletion. The simulated ozone mixing ratios compare well with satellite and in situ observations. Key Points: The Arctic vortex was exceptionally cold and stable in winter 2019/2020 resulting in substantial Arctic ozone depletionArctic ozone loss in 2020 exceeded that in the cold Arctic springs of 2011 and 2016 that had previously shown the strongest ozone depletionSignificant chlorine deactivation into HCl occurred, as is regularly observed in Antarctica [ABSTRACT FROM AUTHOR]

The X-Ray (00L) and (HK0) patterns of third stage graphite intercalation compound with bromine have been experimentally investigated in the range of (150–290) K. The dependence of the intercalate identity parameter on temperature is determined. In the temperature range of (150–290) K there are three temperature intervals with different values of the linear thermal expansion coefficient (α): α I = (3.3 ± 0.2) ⋅ 10 − 5 К−1 in range I (238–300)K, α I I = (2.8 ± 0.2) ⋅ 10 − 5 К−1 in range II (174–238) K and α III = (2.4 ± 0.2) ⋅ 10 − 5 К−1 in range III (150–174) K. The abrupt change of the linear thermal expansion coefficient has been detected at 238 K and 174 K. The redistribution of the intensities of the (HK0) pattern main components on cooling from the 290 K to 150 K, in particular, a decrease of some maxima intensities indicates the active migration processes of bromine molecules in the two-dimensional lattice of the intercalate. [ABSTRACT FROM AUTHOR]

Postmodification methods are effective tools in preparing functional polymers, and novel end‐group reactions have attracted much attention from researchers for postmodification applications. Here, a new high‐efficiency postmodification method is proposed, which can change bromine‐containing polymers to functional polymers in one step. Phenol, 1‐hydroxynaphthalene, and 4‐(2‐phenyldiazenyl)‐phenol (AzoOH) are successfully grafted onto the polymeric branch chain of bromine‐containing polymers, i.e., homopolymer, bromoethyl methyl acrylate, (pBMEA) and amphiphilic block copolymer p(BMEA)‐b‐p(mPEG), with a high grafting rate that is near 100%. Also, the micelles of the postmodified amphiphilic block copolymer p(BMEA‐Azo)‐b‐p(mPEG) are broken up under ultraviolet irradiation. The proposed method can be used as a platform to prepare a variety of stimuli‐responsive polymeric nanoparticles. [ABSTRACT FROM AUTHOR]

In spring 2011, columns of bromine monoxide (BrO) were retrieved over Fairbanks, Alaska using a ground‐based multifunction differential optical absorption spectroscopy (MFDOAS) instrument. MFDOAS vertical column BrO is consistently lower than retrievals from the satellite‐based Ozone Monitoring Instrument (OMI), with a relative bias of 20 ± 14%. Numerous tropical‐based studies suggest that 5 ± 2 parts per trillion (ppt) of bromine from very short‐lived substances (VSLS) reaches the stratosphere. We evaluate upper limits on the contribution of VSLS to stratospheric bromine by treating the column retrievals of BrO as purely stratospheric and modeling the ratio of BrO to total inorganic bromine. The OMI and MFDOAS retrievals respectively present 8 and 5 ppt upper limits on the stratospheric injection of VSLS, and kinetic uncertainties in the daytime partitioning of bromine species decrease both values by ∼1.7 ppt. The OMI‐based estimate is in agreement with the 5 ppt tropical‐based value for stratospheric injection of VSLS if the tropospheric column of BrO is 1.5 × 1013 molecules cm−2 over Fairbanks, which is within the range of uncertainty of a second ground‐based instrument that monitored tropospheric BrO during the campaign. Because our ground‐based instruments detected no BrO near the surface, this value for tropospheric BrO would originate from higher altitudes in the troposphere and is in agreement with previous retrievals of background tropospheric BrO. Our calculations of tropospheric BrO over Fairbanks are most sensitive to uncertainties in the stratospheric loading of VSLS, followed by the difference between the OMI and MFDOAS retrievals of BrO. Key Points: Retrievals of column bromine monoxide (BrO) suggest upper limits for stratospheric injection of bromine from very short‐lived species are 4–8 pptSatellite retrievals are consistent with injection of 5 ppt if tropospheric BrO is 1.5 × 1013 cm−2 over Fairbanks, Alaska in spring 2011Ground‐based vertical column BrO is 20% lower than satellite data and suggests tropospheric BrO is less than 1 × 1013 cm−2 over Fairbanks [ABSTRACT FROM AUTHOR]

The aim of this study was to validate a GC-MS/MS method for determining acrylamide (AA) in potato-based products by using the solid-phase extraction (SPE) clean-up. The method consisted in defatting the sample (potato chips, French fries) with hexane, extraction of AA in water, centrifugation, followed by AA purification on two SPE columns. The purified extract was derivatized with bromine compounds, then extracted with ethyl acetate: hexane mixture. The residue dissolved in ethyl acetate and triethylamine was injected into the GC-MS/MS. The method showed a good precision (RSDr= 1.13-4.26%; RSDR= 1.19-8.84%) and accuracy (recovery= 85.64-109.22%). The precision of the results was demonstrated by participation in two proficiency tests launched by the FAPAS® program, yielding z-scores of -0.8 (for pre-cooked French fries) and 0 (for potato crisps). Good sensitivity was achieved for potato chips with a LOD and LOQ of 6.94 and 20.83 µg/kg, while for French fries, it was 10.29 and 30.87 µg/kg, respectively. When applying the method on potato chips sample, the AA level varied between undetectable and 1504.93 µg/kg, while for French fries was between 31.45-371.30 µg/kg. The method fulfilled the performance criteria of Commission Regulation EU 2017/2158 for the determination of AA in potato-based products. [ABSTRACT FROM AUTHOR]

The photofragmentation dynamics of BrCN- in the 270-355 nm and the 430-600 nm wavelength regions is explored both experimentally and theoretically. In the case of excitation between 430 nm and 600 nm, it is found that the molecular ion accesses two dissociation channels with a measured 60:40 branching ratio that is nearly constant over this range of photon energies. The dominant product channel corresponds to Br- + CN, while the second channel correlates to spin-orbit excited Br* with CN- . A larger wavelength dependence of the branching ratio is observed at shorter wavelengths, where the fraction of Br- based products ranges from 80% to 95% at 355 nm and 270 nm, respectively. These branching ratios are reproduced and the mechanisms are explored by quantum dynamics calculations based on ground and excited state potential energy surfaces for BrCN-, evaluated at the SO-MRCISD level of theory. It is found that the electronic states that correlate to the two observed product channels are coupled through the spin-orbit terms in the electronic Hamiltonian. The strength of this coupling displays a strong dependence on the Br-CN angle. Specifically, after promotion to the excited state that is energetically accessible with 430-600 nm photons, it is found that when the wave packet accesses Br-CN separations of between 4 Â and 6 Â, predominantly the Br- + CN products are formed when the Br-CN angle is smaller than 120°. For larger values of the Br-CN angle, the Br* + CN- channel dominates. At the shorter wavelength excitation, the dynamics is complicated by a pair of states that correlate to electronically excited CN* + Br- products that borrow oscillator strength from the bright state, leading to an increase in the amount of Br- relative to CN- . The implications of these findings are discussed and compared to the experimentally measured product branching ratios for the photodissociation of BrCN- . [ABSTRACT FROM AUTHOR]

The photofragmentation dynamics of BrCN- in the 270-355 nm and the 430-600 nm wavelength regions is explored both experimentally and theoretically. In the case of excitation between 430 nm and 600 nm, it is found that the molecular ion accesses two dissociation channels with a measured 60:40 branching ratio that is nearly constant over this range of photon energies. The dominant product channel corresponds to Br- + CN, while the second channel correlates to spin-orbit excited Br* with CN- . A larger wavelength dependence of the branching ratio is observed at shorter wavelengths, where the fraction of Br- based products ranges from 80% to 95% at 355 nm and 270 nm, respectively. These branching ratios are reproduced and the mechanisms are explored by quantum dynamics calculations based on ground and excited state potential energy surfaces for BrCN-, evaluated at the SO-MRCISD level of theory. It is found that the electronic states that correlate to the two observed product channels are coupled through the spin-orbit terms in the electronic Hamiltonian. The strength of this coupling displays a strong dependence on the Br-CN angle. Specifically, after promotion to the excited state that is energetically accessible with 430-600 nm photons, it is found that when the wave packet accesses Br-CN separations of between 4 Â and 6 Â, predominantly the Br- + CN products are formed when the Br-CN angle is smaller than 120°. For larger values of the Br-CN angle, the Br* + CN- channel dominates. At the shorter wavelength excitation, the dynamics is complicated by a pair of states that correlate to electronically excited CN* + Br- products that borrow oscillator strength from the bright state, leading to an increase in the amount of Br- relative to CN- . The implications of these findings are discussed and compared to the experimentally measured product branching ratios for the photodissociation of BrCN- . [ABSTRACT FROM AUTHOR]

With the decrease of CMOS device dimensions, the linewidth roughness (LWR) of transistor gates is being recognized as a major concern. In integrated circuit manufacturing, an HBr plasma treatment has been used so far to reduce the LWR of photoresist (PR) lines printed by 193 nm lithography before transfer into the gate stack by plasma etching. In this article, a more efficient treatment based on HBr/O2 plasma exposure followed by a bake is developed, and the plasma conditions are optimized. We show that by controlling the dose of vacuum ultra violet (VUV) light emitted by the HBr/O2 plasma, the PR bulk can be either softened (photolysis) or strengthened (crosslinking). Moreover, the PR surface properties can be controlled by the O2 content of the plasma. The surface and bulk properties of the PR line after plasma treatment determine the LWR behavior during the subsequent thermal cure treatment. A soft resist bulk combined with a thin surface carbon layer is the ideal case to get the best LWR smoothing effect during the subsequent bake without reflowing. By optimizing both the plasma oxygen content and the VUV dose, we obtained a 59% LWR decrease (from 7.3 nm to 3.0 nm) using an HBr/O2 plasma treatment followed by a bake. The detailed study on the impact of the VUV dose during the plasma treatment permitted to determine the sidewall smoothing mechanisms involved. During both the plasma and the thermal treatments, the outgassing of the products of photolysis or deprotection reactions followed by the re-densification of the polymer material is shown to be the main sidewall smoothing enabler. [ABSTRACT FROM AUTHOR]

The proprotein convertases family is involved in several physiological processes such as cell growth, migration, and angiogenesis, and also in different pathological conditions. Evolocumab, an inhibitor of proprotein convertase subtilisin/kexin type 9 (PCSK9), has recently been approved for treatment of hypercholesterolemia. This study aimed to investigate the effect of evolocumab on angiogenesis in human umbilical vein endothelial cells (HUVECs). Cell proliferation and migration were evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and Transwell methods. In vitro angiogenesis was assessed by tube formation assay. Vascular endothelial growth factor (VEGF) secretion by HUVECs was also determined using an enzyme-linked immunosorbent assay kit. Evolocumab significantly increased HUVECs viability at 100[micro]g/mL. Significant enhancement in cell migration, and mean tubules length and size was observed at the concentrations of 10 and 100[micro]g/mL and also in mean number of junctions at the concentration of 100[micro]g/mL. Administration of evolocumab at the concentration of 10[micro]g/mL increased VEGF release into supernatants of HUVECs. Findings of this investigation provided in vitro evidence for pro-angiogenic activity of evolocumab through promoting cell proliferation, migration, tubulogenesis, and VEGF secretion in HUVECs. Key words: angiogenesis, cell proliferation, cell migration, HUVEC, PCSK9, evolocumab, VEGF. La famille des proproteine convertases joue un role dans plusieurs processus physiologiques comme la croissance cellulaire, la migration cellulaire et l'angiogenese, ainsi que dans differents etats pathologiques. L'evolocumab, un inhibiteur de la proproteine convertase subtilisine/kexine de type 9 (PCSK9), a recemment ete approuve dans le traitement de l'hypercholesterolemie. Ces travaux visaient a etudier l'effet de l'evolocumab sur l'angiogenese dans les cellules endotheliales des veines ombilicales chez l'humain (HUVEC). Nous avons evalue la proliferation et la migration cellulaires a l'aide des methodes dubromure de (4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium et de Transwell. Nous avons evalue l'angiogenese in vitro a l'aide de l'epreuve de formation de tubes. Nous avons aussi evalue la secretion du VEGF (pour << vascular endothelial growth factor>>) par les cellules HUVEC a l'aide d'un kit d'ELISA (pour<< enzyme-linked immunosorbent assay>>). L'evolocumab a 100[micro]g/mL permettait d'augmenter la vitalite des cellules HUVEC de facon marquee. Nous avons observe une nette augmentation de la migration des cellules et des longueurs et des tailles moyennes des tubules a des concentrations de 10 et de 100[micro]g/mL, avec une augmentation du nombre moyen de jonctions a la concentration de 100[micro]g/mL. A la concentration de 10[micro]g/mL, l'administration d'evolocumab entrainait une augmentation de la liberation de VEGF dans le liquide surnageant les cellules HUVEC. Les resultats de cette etude ont permis d'obtenir des donnees in vitro temoignant de l'activite proangiogenique de l'evolocumab par l'intermediaire de l'augmentation de la proliferation, de la migration, de la tubulogenese et de la secretion de VEGF avec les cellules HUVEC. [Traduit par la Redaction] Mots-cles: angiogenese, proliferation cellulaire, migration cellulaire, HUVEC, PCSK9, evolocumab, VEGF., Introduction Angiogenesis is the formation and growing of new blood vessels from pre-existing vasculature during several normal and pathological situations (Goodwin 2007). This process involves a sequence of organized steps [...]

This study investigated the role and action of the Salvador 1 protein (SAV1, also called WW45) in colorectal cancer (CRC). For this, CRC SW480 and HCT116 cells were infected with lentiviruses of SAV1 overexpression vector (lenti-SAV1) and SAV1 short hairpin RNA (sh-SAV1) to overexpress and silence SAV1 respectively, or transfected with microRNA-21 (miR-21) mimic to overexpress miR-21. Relative mRNA levels of SAV1 and relative miR-21 levels in CRC tissues or cells were detected. The effects of SAV1 and miR-21 on cell proliferation and apoptosis were evaluated using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay and annexin V - fluorescein isothiocyanate (FITC) - propidium iodide (PI) flow cytometry, respectively. Our results revealed that SAV1 was downregulated in CRC tissues compared with the adjacent noncancerous tissues. Furthermore, SAV1 overexpression inhibited proliferation and promoted apoptosis in SW480 and HCT116 cells, whereas knockdown of SAV1 exerted the opposite effect. Additionally, the tumorigenesis of SW480 cells in xenografted mice was significantly inhibited by SAV1 overexpression but promoted by SAV1 knockdown. MiR-21 levels significantly and negatively correlated with SAV1 expression in CRC tissues. More importantly, miR-21 overexpression significantly abolished the SAV1-mediated inhibition of proliferation and stimulation of apoptosis of SW480. In conclusion, SAV1 suppresses tumor growth in CRC and is regulated by miR-21. Key words: colorectal cancer, SAV1, miR-21, tumor growth, apoptosis. Cette etude visait a examiner le role et l'action de la proteine Salvador 1 (SAV1, aussi appelee WW45) dans le cancer colorectal (CCR). Les cellules de CCR SW480 et HCT116 ont ete infectees avec un vecteur de surexpression lentiviral de SAV1 (lenti-SAV1) et un petit ARN en epingle a cheveux de SAV1 (shSAV1) pour surexprimer ou reprimer SAV1, respectivement. Les cellules ont aussi ete transfectees avec un mime du microARN-21 (miR-21) pour surexprimer miR-21. Les niveaux relatifs de l'ARN de SAV1 et de miR-21 dans les tissus ou les cellules de CCR ont ete mesures. Les effets de SAV1 et de miR-21 sur la proliferation cellulaire et l'apoptose ont ete evalues par un dosage au bromure de 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) et une analyse en cytometrie en flux du marquage a l'annexine V - isothiocyanate de fluoresceine (FITC) - iodure de propidium (IP), respectivement. Les resultats des auteurs ont revele que SAV1 etait regulee a la baisse dans les tissus de CCR comparativement aux tissus non cancereux adjacents. De plus, la surexpression de SAV1 inhibait la proliferation et favorisait l'apoptose des cellules SW480 et HTC116, alors que le knockdown de SAV1 produisait l'effet contraire. En outre, le potentiel tumorigene des cellules SW480 chez des souris porteuses de xenogreffes etait significativement inhibe par la surexpression de SAV1, mais favorise par le knockdown de SAV1. Le niveau de miR-21 etait significativement et negativement correle a l'expression de SAV1 dans les tissus de CCR. Mais surtout, la surexpression de miR-21 abolissait significativement l'inhibition de la proliferation et la stimulation de l'apoptose relayees par SAV1 chez les cellules SW480. En conclusion, SAV1 supprimait la croissance des tumeurs colorectales et elle etait regulee par miR-21. [Traduit par la Redaction] Mots-cles : cancer colorectal, SAV1, miR-21, croissance tumorale, apoptose., Introduction Colorectal cancer (CRC) is one of the most prevalent and most deadly cancers worldwide (Ferlay et al. 2015; Abe et al. 2016; Sayagues et al. 2016). It is the [...]

Changes in the indicator electrode potential (at zero current) E and (quasi) equilibrium composition of aqueous solution in the anode chamber of the model electrolyzer, which initially contained 0.5 M concentration of bromide anions, provided that the solution was kept at a constant pH and constant (together with the gas phase above it) total number of Br atoms in all its compounds, are calculated. Theoretical analysis was carried out for four different hypotheses regarding the possible extent of electrolysis and the nature of the processes are theoretically analyzed. They are: (1) no formation of bromine compounds with positive oxidation states occurs, i.e., electrolysis only leads to the formation of molecular bromine in its various forms (the dissolved state of Br2, as well as phases of liquid bromine , and bromine vapor in the gas space above the solution); (2) oxidation of bromide ions leads to the formation of bromine compounds in its oxidation state up to +1 inclusive; (3) the process proceeds with the formation of both bromate ion (BrO3-) and compounds of bromine with lower oxidation states in solution ( Br2, BrO–, HBrO); (4) in addition to the components specified in clause (3), the formation of the perbromate anion is also taken into consideration. All electrochemical and chemical reactions involving bromine-containing species have been taken into consideration in the hypothesis framework of the system's evolution (1), (2), (3), or (4), are assumed to be in a (quasi)equilibrium state. Predictions for all hypotheses (1), (2), (3), or (4) have been compared at three different pH values of the solution (2, 6 and 10 of Br-containing anolyte composition's evolution in the course of electrolysis. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) materials, consisting of atomically thin crystal layers bound by the van der Waals force, have attracted much interest because of their potential in diverse technologies, including electronics, optoelectronics and catalysis.sup.1-10. In particular, solution-processable 2D semiconductor (such as MoS.sub.2) nanosheets are attractive building blocks for large-area thin-film electronics. In contrast to conventional zero- and one-dimensional nanostructures (quantum dots and nanowires, respectively), which are typically plagued by surface dangling bonds and associated trapping states, 2D nanosheets have dangling-bond-free surfaces. Thin films created by stacking multiple nanosheets have atomically clean van der Waals interfaces and thus promise excellent charge transport.sup.11-15. However, preparing high-quality solution-processable 2D semiconductor nanosheets remains a challenge. For example, MoS.sub.2 nanosheets and thin films produced using lithium intercalation and exfoliation are plagued by the presence of the metallic 1T phase and poor electrical performance (mobilities of about 0.3 square centimetres per volt per second and on/off ratios of less than 10).sup.2,12, and materials produced by liquid exfoliation exhibit an intrinsically broad thickness distribution, which leads to poor film quality and unsatisfactory thin-film electrical performance (mobilities of about 0.4 square centimetres per volt per second and on/off ratios of about 100).sup.14,16,17. Here we report a general approach to preparing highly uniform, solution-processable, phase-pure semiconducting nanosheets, which involves the electrochemical intercalation of quaternary ammonium molecules (such as tetraheptylammonium bromide) into 2D crystals, followed by a mild sonication and exfoliation process. By precisely controlling the intercalation chemistry, we obtained phase-pure, semiconducting 2H-MoS.sub.2 nanosheets with a narrow thickness distribution. These nanosheets were then further processed into high-performance thin-film transistors, with room-temperature mobilities of about 10 square centimetres per volt per second and on/off ratios of 10.sup.6 that greatly exceed those obtained for previous solution-processed MoS.sub.2 thin-film transistors. The scalable fabrication of large-area arrays of thin-film transistors enabled the construction of functional logic gates and computational circuits, including an inverter, NAND, NOR, AND and XOR gates, and a logic half-adder. We also applied our approach to other 2D materials, including WSe.sub.2, Bi.sub.2Se.sub.3, NbSe.sub.2, In.sub.2Se.sub.3, Sb.sub.2Te.sub.3 and black phosphorus, demonstrating its potential for generating versatile solution-processable 2D materials.By intercalating large ammonium molecules to exfoliate MoS.sub.2 with preservation of the 2H-phase, highly uniform solutionprocessable 2D semiconductor nanosheets are obtained for the scalable fabrication of large-area thin-film electronics., Author(s): Zhaoyang Lin [sup.1] , Yuan Liu [sup.2] [sup.3] , Udayabagya Halim [sup.1] , Mengning Ding [sup.2] , Yuanyue Liu [sup.4] , Yiliu Wang [sup.1] , Chuancheng Jia [sup.2] , [...]

We analyzed the transient absorption properties of TlBr crystals using pulsed electron beams as excitation sources. We observed transient absorption spectra and temporal profiles on the pico- and nanosecond scales and compared the results obtained for TIBr crystals that are empirically appropriate with those that are inappropriate for semiconductor detectors. The results showed negligible differences in properties between the two types of crystal, which indicates that their trap center concentrations were similar. A transient absorption band was observed at approximately 1160 nm on the nanosecond scale, while its short-wavelength tail was observed on the picosecond scale. The absorption band is attributed to the localized holes at Tl+ that are stabilized by some defects. In contrast, no absorption band attributable to localized electron centers was observed, indicating that while hole transport is hindered by defects, electron transport is not [ABSTRACT FROM AUTHOR]

Previously unknown 4a-aza-12a-borachrysene has been synthesized in only four steps. The reactions of this BN-embedded PAH with bromine and organolithium compounds proceed with complete regioselectivity, resulting in the formation of nine derivatives. One of these, a phenylalkynyl-substituted derivative, exhibits a remarkably high fluorescence quantum yield (ΦF = 0.68). [ABSTRACT FROM AUTHOR]

The changes in indicator-electrode potential and (quasi)equilibrium solution composition in the anodic compartment of a model electrolyzer initially filled with aqueous electrolyte containing 0.5 M concentration of bromide anions are calculated under the condition that pH 2 is maintained constant in this compartment. The theoretical analysis is carried out for three different hypotheses concerning the possible depth of electrolysis and the nature of processes involved: (1) no bromine compounds with positive degree of oxidation are formed; (2) bromine compounds with the degree of oxidation not higher than +1 are formed; (3) the process can involve the formation of both bromate ions and bromine compounds with the lower degrees of oxidation ( Br2, BrO–, HBrO) in solution as well as the liquid phase of bromine All electrochemical and chemical reactions involving bromine-containing species taken into account within the framework of hypotheses of system evolution 1, 2, and 3 are assumed to be (quasi)equilibrium, and the electric current through the cell separator is assumed to be provided by supporting electrolyte ions. Methods are proposed for experimental determination of the version of evolution of Br-containing anolyte during electrolysis. [ABSTRACT FROM AUTHOR]

The [1+1] two-photon dissociation dynamics of mass-selected 79Br2+ has been studied in a cold ion beam using a cryogenic cylindrical ion trap velocity map imaging spectrometer. The quartet 1 4 Σ u , 3 / 2 − state of 79Br2+ is employed as an intermediate state to initiate resonance enhanced two-photon excitation to high-lying dissociative states in the 4.0–5.0 eV energy region above the ground rovibronic state. Total kinetic energy release (TKER) and the two-dimensional recoiling velocity distributions of fragmented 79Br+ ions are measured using the technique of DC-slice velocity map imaging. Branching ratios for individual state-resolved product channels are determined from the TKER spectra. The measured photofragment angular distributions indicate that the dissociation of 79Br2+ occurs in dissociative Ω=3/2 state via ΔΩ=0 parallel transition from the 1 4 Σ u , 3 / 2 − intermediate state. Due to the considerable spin-orbit coupling effects in the excited states of 79Br2+, higher-lying dissociative quartet states are likely responsible for the observed photodissociation processes. [ABSTRACT FROM AUTHOR]