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1
Wang, Lixuan, Shiyan Dong, Yutong Liu, Yifan Ma, Jingjing Zhang, Zhaogang Yang, Wen Jiang, and Yuan Yuan. "Fabrication of Injectable, Porous Hyaluronic Acid Hydrogel Based on an In-Situ Bubble-Forming Hydrogel Entrapment Process." Polymers 12, no. 5 (May 16, 2020): 1138. http://dx.doi.org/10.3390/polym12051138.
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Injectable hydrogels have been widely applied in the field of regenerative medicine. However, current techniques for injectable hydrogels are facing a challenge when trying to generate a biomimetic, porous architecture that is well-acknowledged to facilitate cell behaviors. In this study, an injectable, interconnected, porous hyaluronic acid (HA) hydrogel based on an in-situ bubble self-generation and entrapment process was developed. Through an amide reaction between HA and cystamine dihydrochloride activated by EDC/NHS, CO2 bubbles were generated and were subsequently entrapped inside the substrate due to a rapid gelation-induced retention effect. HA hydrogels with different molecular weights and concentrations were prepared and the effects of the hydrogel precursor solution’s concentration and viscosity on the properties of hydrogels were investigated. The results showed that HA10-10 (10 wt.%, MW 100,000 Da) and HA20-2.5 (2.5 wt.%, MW 200,000 Da) exhibited desirable gelation and obvious porous structure. Moreover, HA10-10 represented a high elastic modulus (32 kPa). According to the further in vitro and in vivo studies, all the hydrogels prepared in this study show favorable biocompatibility for desirable cell behaviors and mild host response. Overall, such an in-situ hydrogel with a self-forming bubble and entrapment strategy is believed to provide a robust and versatile platform to engineer injectable hydrogels for a variety of applications in tissue engineering, regenerative medicine, and personalized therapeutics.
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Rabel, R. A. C., L. Osterbur, A. Maki, J. Lewis, and M. B. W. Wheeler. "193 HYALURONIC ACID-GLYCIDYL METHACRYLATE HYDROGELS SUPPORT IN VITRO CHONDROGENIC DIFFERENTIATION OF PORCINE ADIPOSE-DERIVED STEM CELLS." Reproduction, Fertility and Development 26, no. 1 (2014): 211. http://dx.doi.org/10.1071/rdv26n1ab193.
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There is a great need for bioengineered cartilage because of the lack of medical or surgical therapies to improve articular cartilage healing. We hypothesised that porcine adipose-derived stem cells (pASC) can be induced to undergo chondrogenic differentiation within hyaluronic acid (HA) hydrogels. The objective of this study was to develop UV-curable pASC-laden HA hydrogels aimed at application in cartilage tissue engineering. HA was treated with glycidyl methacrylate (GM) to allow chemical gelation of the polymer upon exposure to UV light. 2% HAGM hydrogel was obtained by mixing HAGM with chondrogenic medium consisting of TGFβ, ascorbic acid, ITS+ premix (insulin, transferrin, selenous acid; Cat. No. 354352, BD Biosciences, Franklin Lakes, NJ), sodium pyruvate, and dexamethasone. Passage three-pASC were resuspended in 2% HAGM hydrogel with 2 × 107 cells mL–1. Twelve-and-one-half (12.5)-μL droplets (micromasses) of this suspension containing 250 000 pASC were placed in 24-well culture plates and incubated for 2 h at 37°C and 5% CO2 to allow for cell attachment. Subsequently, the cell-laden hydrogels were cured with ~10 mW cm–2 365-nm UV light for 10 min, covered with 500 μL of chondrogenic medium, and cultured for up to 11 days at 37°C and 5% CO2. Additionally, pASC micromasses were cultured in chondrogenic medium without loading on 2% HAGM hydrogels as positive controls, and in non-chondrogenic DMEM as negative controls. Samples were collected at 4, 7, and 11 days in to culture for cryopreservation (for immunohistochemistry; IHC) and dimethylmethylene blue (DMMB) assay. IHC on day 11 of culture demonstrated the expression of cartilage specific proteins type-II collagen and aggrecan. On the basis of data from the DMMB assay, chondrogenic differentiation of pASC-laden micromasses in positive controls and 2% HAGM treatments were not different (P > 0.05). This indicates that ASC can produce cartilage equally well under both conditions, supporting the idea that HAGM may be used as a matrix for cartilage formation in vitro and possibly in vivo. In conclusion, using a micromass cell culture system, we demonstrated that 2% HAGM hydrogels support proliferation and chondrogenic differentiation of pASC. Further experiments testing different concentrations of HAGM and UV exposure levels, and larger sample numbers are warranted to further improve this procedure.
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Pham, Bao Ngoc, Giang Nguyen, Van Toan Le, Xuan Cuong Le, Minh Hiep Nguyen, Ngoc Bich Dao Vu, Thi Tam Tran, et al. "Study on the adsorption of heavy metal ions Pb2+, Zn2+, Co2+, Ni2+from the aqueous solution of the copolymer prepared by gamma induced radiationpolymerization." Ministry of Science and Technology, Vietnam 63, no. 3 (March 30, 2021): 6–11. http://dx.doi.org/10.31276/vjst.63(3).06-11.
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Copolymer hydrogel (PVA-g-AA) having varied PVA (Polyvinyl alcohol) and AA (Acrylic acid) content is prepared by gamma induced radiation polymerization. The parameters affecting the gel fraction yield have been studied. The gel fraction and the swelling property are found to be 92.39 and 905% respectively at an absorbed dose of 20 kGy. Structural and property characteristics were determined by Fourier Transform Infrared (FTIR) spectrometer and Differential Scanning Calorimetry (DSC). The surface morphology of PVA and copolymer has been studied with Scanning Electron Microscope (SEM). The factors affecting the metal uptake such as pH, time, and initial feed metal concentration were investigated. It is found that at pH 5 and after 240 minutes the maximum adsorption amount are 178, 161, 117, and 110 mg/g for Pb2+, Zn2+, Co2+, and Ni2+ respectively.
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Dilling, Sabrina, Frank Imkamp, Silke Schmidt, and Volker Müller. "Regulation of Caffeate Respiration in the Acetogenic Bacterium Acetobacterium woodii." Applied and Environmental Microbiology 73, no. 11 (April 6, 2007): 3630–36. http://dx.doi.org/10.1128/aem.02060-06.
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ABSTRACT The anaerobic acetogenic bacterium Acetobacterium woodii can conserve energy by oxidation of various substrates coupled to either carbonate or caffeate respiration. We used a cell suspension system to study the regulation and kinetics of induction of caffeate respiration. After addition of caffeate to suspensions of fructose-grown cells, there was a lag phase of about 90 min before caffeate reduction commenced. However, in the presence of tetracycline caffeate was not reduced, indicating that de novo protein synthesis is required for the ability to respire caffeate. Induction also took place in the presence of CO2, and once a culture was induced, caffeate and CO2 were used simultaneously as electron acceptors. Induction of caffeate reduction was also observed with H2 plus CO2 as the substrate, but the lag phase was much longer. Again, caffeate and CO2 were used simultaneously as electron acceptors. In contrast, during oxidation of methyl groups derived from methanol or betaine, acetogenesis was the preferred energy-conserving pathway, and caffeate reduction started only after acetogenesis was completed. The differential flow of reductants was also observed with suspensions of resting cells in which caffeate reduction was induced prior to harvest of the cells. These cell suspensions utilized caffeate and CO2 simultaneously with fructose or hydrogen as electron donors, but CO2 was preferred over caffeate during methyl group oxidation. Caffeate-induced resting cells could reduce caffeate and also p-coumarate or ferulate with hydrogen as the electron donor. p-Coumarate or ferulate also served as an inducer for caffeate reduction. Interestingly, caffeate-induced cells reduced ferulate in the absence of an external reductant, indicating that caffeate also induces the enzymes required for oxidation of the methyl group of ferulate.
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Kim, Hak-Sung, and Gye-Chun Cho. "Experimental Simulation of the Self-Trapping Mechanism for CO2 Sequestration into Marine Sediments." Minerals 9, no. 10 (September 24, 2019): 579. http://dx.doi.org/10.3390/min9100579.
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CO2 hydrates are ice-like solid lattice compounds composed of hydrogen-bonded cages of water molecules that encapsulate guest CO2 molecules. The formation of CO2 hydrates in unconsolidated sediments significantly decreases their permeability and increases their stiffness. CO2 hydrate-bearing sediments can, therefore, act as cap-rocks and prevent CO2 leakage from a CO2-stored layer. In this study, we conducted an experimental simulation of CO2 geological storage into marine unconsolidated sediments. CO2 hydrates formed during the CO2 liquid injection process and prevented any upward flow of CO2. Temperature, pressure, P-wave velocity, and electrical resistance were measured during the experiment, and their measurement results verified the occurrence of the self-trapping effect induced by CO2 hydrate formation. Several analyses using the experimental results revealed that CO2 hydrate bearing-sediments have a considerable sealing capacity. Minimum breakthrough pressure and maximum absolute permeability are estimated to be 0.71 MPa and 5.55 × 10−4 darcys, respectively.
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Gu, Qihai, and Lu-Yuan Lee. "Alveolar hypercapnia augments pulmonary C-fiber responses to chemical stimulants: role of hydrogen ion." Journal of Applied Physiology 93, no. 1 (July 1, 2002): 181–88. http://dx.doi.org/10.1152/japplphysiol.00062.2002.
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To determine whether the excitabilities of pulmonary C fibers to chemical and mechanical stimuli are altered by CO2-induced acidosis, single-unit pulmonary C-fiber activity was recorded in anesthetized, open-chest rats. Transient alveolar hypercapnia (HPC) was induced by administering CO2-enriched gas mixture (15% CO2, balance air) via the respirator inlet for 30 s, which rapidly lowered the arterial blood pH from a baseline of 7.40 ± 0.01 to 7.17 ± 0.02. Alveolar HPC markedly increased the responses of these C-fiber afferents to several chemical stimulants. For example, the C-fiber response to right atrial injection of the same dose of capsaicin (0.25–1.0 μg/kg) was significantly increased from 3.07 ± 0.70 impulses/s at control to 8.48 ± 1.52 impulses/s during HPC ( n = 27; P < 0.05), and this enhanced response returned to control within ∼10 min after termination of HPC. Similarly, alveolar HPC also induced significant increases in the C-fiber responses to right atrial injections of phenylbiguanide (4–8 μg/kg) and adenosine (0.2 mg/kg). In contrast, HPC did not change the response of pulmonary C fibers to lung inflation. Furthermore, the peak response of these C fibers to capsaicin during HPC was greatly attenuated when the HPC-induced acidosis was buffered by infusion of bicarbonate (1.36–1.82 mmol · kg−1 · min−1 for 35 s). In conclusion, alveolar HPC augments the responses of these afferents to various chemical stimulants, and this potentiating effect of CO2 is mediated through the action of hydrogen ions on the C-fiber sensory terminals.
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Parigger, Christian G., Christopher M. Helstern, and Ghaneshwar Gautam. "Temporally and Spatially Resolved Emission Spectroscopy of Hydrogen, Cyanide and Carbon in Laser-Induced Plasma." Atoms 7, no. 3 (August 2, 2019): 74. http://dx.doi.org/10.3390/atoms7030074.
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In this study, we examine the atomic and molecular signatures in laser-induced plasma. Abel inversions of measured line-of-sight data reveal insight into the radial plasma distribution. Laser-plasma is generated with 6 ns, Q-switched Nd:YAG radiation with energies in the range of 100 to 800 mJ. Temporally- and spatially-resolved emission spectroscopy investigates expansion dynamics. Specific interests include atomic hydrogen (H) and cyanide (CN). Atomic hydrogen spectra indicate axisymmetric shell structures and isentropic expansion of the plasma kernel. The recombination radiation of CN emanates within the first 100 nanoseconds for laser-induced breakdown in a 1:1 mole ratio CO2:N2 gas mixture. CN excitation temperatures are determined from fitting recorded and computed spectra. Chemical equilibrium mole fractions of CN are computed for air and the CO2:N2 gas mixture. Measurements utilize a 0.64-m Czerny–Turner type spectrometer and an intensified charge-coupled device.
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Boulard, Eglantine, François Guyot, Nicolas Menguy, Alexandre Corgne, Anne-Line Auzende, Jean-Philippe Perrillat, and Guillaume Fiquet. "CO2-induced destabilization of pyrite-structured FeO2Hx in the lower mantle." National Science Review 5, no. 6 (March 15, 2018): 870–77. http://dx.doi.org/10.1093/nsr/nwy032.
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Abstract Volatiles, such as carbon and water, modulate the Earth's mantle rheology, partial melting and redox state, thereby playing a crucial role in the Earth's internal dynamics. We experimentally show the transformation of goethite FeOOH in the presence of CO2 into a tetrahedral carbonate phase, Fe4C3O12, at conditions above 107 GPa—2300 K. At temperatures below 2300 K, no interactions are evidenced between goethite and CO2, and instead a pyrite-structured FeO2Hx is formed as recently reported by Hu et al. (2016; 2017) and Nishi et al. (2017). The interpretation is that, above a critical temperature, FeO2Hx reacts with CO2 and H2, yielding Fe4C3O12 and H2O. Our findings provide strong support for the stability of carbon-oxygen-bearing phases at lower-mantle conditions. In both subducting slabs and lower-mantle lithologies, the tetrahedral carbonate Fe4C3O12 would replace the pyrite-structured FeO2Hx through carbonation of these phases. This reaction provides a new mechanism for hydrogen release as H2O within the deep lower mantle. Our study shows that the deep carbon and hydrogen cycles may be more complex than previously thought, as they strongly depend on the control exerted by local mineralogical and chemical environments on the CO2 and H2 thermodynamic activities.
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Lu, Peng, Ren Liu, Xin Liu, and Min Wu. "Preparation of Self-supporting Bagasse Cellulose Nanofibrils Hydrogels Induced by Zinc Ions." Nanomaterials 8, no. 10 (October 8, 2018): 800. http://dx.doi.org/10.3390/nano8100800.
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Cellulose hydrogels are often prepared from native cellulose through a direct cellulose dissolution approach that often involves tedious process and solvent recovery problems. A self-supporting cellulose hydrogel was prepared by gelation of the TEMPO-oxidized bagasse cellulose nanofibrils (CNF) triggered by strong crosslinking between carboxylate groups and Zn2+. TEMPO process was used to generate negatively charged carboxylate groups on CNF surface to provide a high binding capability to Zn2+. Three TEMPO-oxidized CNFs of different carboxylate contents were prepared and characterized. TEM and AFM microscopes suggested that the sizes of CNFs were fined down and carboxylated cellulose nanofibrils (TOCNFs) of 5–10 nm wide, 200–500 nm long, and carboxylate contents 0.73–1.29 mmol/g were obtained. The final structures and compressive strength of hydrogels were primarily influenced by interfibril Zn2+-carboxylate interactions, following the order of TOCNFs concentration > content of carboxylate groups > concentration of zinc ions. A CO2 sensitive self-supporting cellulose hydrogel was developed as a colorimetric indicator of food spoilage for intelligent food packaging applications.
10
Earl, Boyd L., and Richard L. Titus. "Novel Products in the CO2-Laser Induced Reaction of Trichloroethylene." Collection of Czechoslovak Chemical Communications 60, no. 1 (1995): 104–14. http://dx.doi.org/10.1135/cccc19950104.
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Previous reports on the thermal or CO2-laser induced decomposition of trichloroethylene have identified only one condensible product, hexachlorobenzene (in addition to HCl and mono- and dichloroacetylene). We have found that trichloroethylene vapor exposed to cw irradiation on the P(24) line of the (001 - 100) band of the CO2 laser at incident power levels from 8 - 17 W produces numerous products, of which the 13 major ones have been identified using IR, GC/MS, GC/FTIR, and NMR methods. All of these products have 4, 6, or 8 carbons, are highly unsaturated, and are completely chlorinated or contain a single hydrogen. C4HCl5 and C6Cl6 isomers (three of each) account for S 55% to 85% of total products (based on peak areas in the total ion chromatograms in GC/MS runs), depending on reaction conditions. In addition to characterizing the products, we discuss the dependence of the product distribution on laser power, irradiation time, and cell geometry, and we outline a possible mechanism.
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Aslanidi, E. B., R. I. Zainulin, N. K. Kalandadze, and J. S. Turischev. "IR-Laser Induced Branch Chain Reaction of Hypofluorites With Hydrogen." Laser Chemistry 13, no. 1 (January 1, 1993): 13–18. http://dx.doi.org/10.1155/1993/94870.
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The parameters of chain explosion occurrence in the mixture of CF3OF or CF2(OF)2 with hydrogen induced by a pulsed CO2-laser were studied experimentally. The ranges of inflammation for the both cases were obtained. IR-fluorescence spectra associated with the chain explosion were studied. The chemical reactions describing the observed process qualitatively are given assuming the chain energy branching.
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Martirosyan, Varsik, Karlen Hovnanyan, and Sinerik Ayrapetyan. "Carbon Dioxide as a Microbial Toxicity Enhancer of Some Antibacterial Agents: A New Potential Water Purification Tool." ISRN Biophysics 2012 (April 22, 2012): 1–7. http://dx.doi.org/10.5402/2012/906761.
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The aim of current paper was to investigate the possibility of increasing the toxicity of calcium hypochlorite (Ca(ClO)2) and hydrogen peroxide (H2O2) on Escherichia coli K-12 by preliminary enrichment of culture media by carbon dioxide (CO2). For this purpose, the microbes sensitivity to H2O2 or/and Ca(ClO)2 at normal and CO2-enriched medium was studied by spectrophotometric, radioisotopic, and electronmicroscopic methods. Ten-minute preincubation in CO2-enriched medium enhanced the toxic effect of both H2O2 or/and Ca(ClO)2 on bacteria as a result of induced growth inhibition, compared to no-CO2 enriched group. Additionally, changes in cell morphology and proliferation were observed. It was demonstrated that the preliminary incubation of microbes in CO2-enriched culture media in nonsupercritical concentration elevate the toxic effect of H2O2 or/and Ca(ClO)2 on microbes. This can serve as a novel, effective, inexpensive, and environmentally friendly approach for water purification from bacteria, further improving the protection of the environment and human health.
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Parigger, Christian G., James O. Hornkohl, and László Nemes. "Time-Resolved Spectroscopy Diagnostic of Laser-Induced Optical Breakdown." International Journal of Spectroscopy 2010 (October 22, 2010): 1–7. http://dx.doi.org/10.1155/2010/593820.
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Transient laser plasma is generated in laser-induced optical breakdown (LIOB). Here we report experiments conducted with 10.6-micron CO2 laser radiation, and with 1.064-micron fundamental, 0.532-micron frequency-doubled, 0.355-micron frequency-tripled Nd:YAG laser radiation. Characterization of laser induced plasma utilizes laser-induced breakdown spectroscopy (LIBS) techniques. Atomic hydrogen Balmer series emissions show electron number density of 1017 cm−3 measured approximately 10 μs and 1 μs after optical breakdown for CO2 and Nd:YAG laser radiation, respectively. Recorded molecular recombination emission spectra of CN and C2 Swan bands indicate an equilibrium temperature in excess of 7000 Kelvin, inferred for these diatomic molecules. Reported are also graphite ablation experiments where we use unfocused laser radiation that is favorable for observation of neutral C3 emission due to reduced C3 cation formation. Our analysis is based on computation of diatomic molecular spectra that includes accurate determination of rotational line strengths, or Hönl-London factors.
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Hainschwang, Thomas, Franck Notari, and Gianna Pamies. "A Defect Study and Classification of Brown Diamonds with Non-Deformation-Related Color." Minerals 10, no. 10 (October 15, 2020): 914. http://dx.doi.org/10.3390/min10100914.
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While the first part of this study took a detailed look at the properties, defects and classification of brown diamonds with deformation-related (DR) brown color and compared them to pink to purple to red diamonds, this second part covers diamonds with non-deformation-related (referred to as NDR in this study) brown color, including diamonds with treatment-induced brown color and synthetic brown diamonds. It was found that the natural NDR brown diamonds include CO2 and Pseudo CO2 diamonds as well as certain hydrogen-rich diamonds. Based on these, the new classification of NDR brown diamonds has been elaborated, resulting in 5 different classes. The detailed defect study performed has shown and confirmed the complexity of the CO2 and Pseudo CO2 diamonds; the probable link between structurally bound oxygen and some of the spectroscopic features such as the 480 nm absorption band is apparent in these diamonds. One of the most interesting findings was made through the low temperature NIR spectroscopy of some usually hydrogen-rich diamonds, which has defined a defect of great interest, the 1330 nm center; we suggest that this defect, together with the many lines in the 970 to 1000 nm range—referred to as the 990 nm series in this study—are responsible for the complex UV-Vis-NIR spectra seen of these diamonds. The results indicate that both features are nickel-nitrogen-related defects, the 1330 nm defect without involvement of hydrogen and the 990 nm series likely with hydrogen involved. Another surprising result was that during various treatment experiments performed we created dark orangish brown color in originally pale yellow “cape” diamonds by HPHT treatment at 2500 °C. It is suggested that the creation of this brown hue is related to the destruction or transformation of the N3 center at such extreme conditions.
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Bian, He-Dong, Xia-Lian Peng, Fu-Ping Huang, Di Yao, Qing Yu, and Hong Liang. "The Spectroscopy Study of the Binding of an Active Ingredient ofDioscoreaSpecies with Bovine Serum Albumin with or without Co2+or Zn2+." Evidence-Based Complementary and Alternative Medicine 2014 (2014): 1–12. http://dx.doi.org/10.1155/2014/247595.
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Diosgenin (DIO) is the active ingredient ofDioscoreaspecies. The interaction of DIO with bovine serum albumin (BSA) was investigated through spectroscopic methods under simulated physiological conditions. The fluorescence quenching data revealed that the binding of DIO to BSA without or with Co2+or Zn2+was a static quenching process. The presence of Co2+or Zn2+both increased the static quenching constantsKSVand the binding affinity for the BSA-DIO system. In the sight of the competitive experiment and the negative values of ΔH0and ΔS0, DIO bound to site I of BSA mainly through the hydrogen bond and Van der Waals’ force. In addition, the conformational changes of BSA were studied by Raman spectra, which revealed that the secondary structure of BSA and microenvironment of the aromatic residues were changed by DIO. The Raman spectra analysis indicated that the changes of conformations, disulfide bridges, and the microenvironment of Tyr, Trp residues of BSA induced by DIO with Co2+or Zn2+were different from that without Co2+or Zn2+.
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Swenson, E. R., and T. H. Maren. "Dissociation of CO2 hydration and renal acid secretion in the dogfish, Squalus acanthias." American Journal of Physiology-Renal Physiology 250, no. 2 (February 1, 1986): F288—F293. http://dx.doi.org/10.1152/ajprenal.1986.250.2.f288.
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Maximal rates of renal hydrogen ion secretion and bicarbonate reabsorption in the dogfish were stimulated by intravascular infusion of acidic and basic buffers: bicarbonate, phosphate, phenol red, dimethadione (DMO), imidazole, and piperazine-N,N'-bis(2 ethanesulfonic acid) (PIPES). There was no difference in titratable acid secretion or urinary pH after bicarbonate infusion despite a sevenfold increase in plasma bicarbonate. Bicarbonate reabsorption was increased 12-fold and showed no evidence of reaching a maximum. This was not altered by methazolamide, as expected, since there is no renal carbonic anhydrase in seagoing fish. Imidazole resulted in the greatest augmentation of renal titratable acid secretion (33----390 mueq . h-1 . kg-1) and did not alter urinary pH. Inhibition of organic base secretion by Darstine had no effect on the imidazole-induced maximal rate of acid secretion. This rate was compared with that of hydrogen ion generation calculated from the uncatalyzed reactions of CO2 and H2O or OH-, maximizing PCO2 and OH- gradients and reaction volumes in vivo. These calculated chemical rates could only account for 9-14% of the measured maximal acidification rate. Thus the powerful process that maintains constant acid urine pH is not only independent of carbonic anhydrase but can function well in a low CO2 environment in which the reactions CO2 + H2O or CO2 + OH- do not furnish enough protons for H+ secretion or HCO3- reabsorption. We conclude that following the cellular protolysis of water, processes other than those involving CO2 buffering of OH- permit H+ to engage in the formation of urine.
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Offenberger, A. A., J. Santiago, M. Fujita, R. Fedosejevs, and W. Rozmus. "Stimulated scattering from laser produced plasma." Laser and Particle Beams 8, no. 1-2 (January 1990): 153–71. http://dx.doi.org/10.1017/s0263034600007916.
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Stimulated Brillouin and Raman scattering are of considerable interest because of their importance to basic nonlinear plasma physics phenomena and to laser-driven inertial confinement fusion. Induced scattering can be substantial for high intensity (I), long wavelength (λ) lasers because the instability growth rates depend exponentially on Jλ2, and also for short wavelength, long scalelength (L) laser/plasma interaction because of nearly homogeneous or large convective gain conditions. Experimental results from both KrF and CO2 laser/plasma interaction studies are presented to illustrate important wavelength dependent features of induced scattering such as the nature of the instability (absolute, convective), threshold, spectra, reflectivity and saturation effects. Backscattering characteristics have been measured for solid target plasmas (aluminum, gold) produced by KrF laser pulses focused to intensities <1014 W/cm2 and gas targets (hydrogen, oxygen) by CO2 laser pulses at intensities <1013 W/cm2. Collisional absorption dominates the KrF laser experiments, whereas particle heating and increased Landau damping dominate the CO2 laser experiments. Current theoretical work concerned with nonlinear effects in Langmuir wave localization, wave collapse and particle heating (generating characteristic high temperature electrons) is also presented.
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Alharbi, Ahad Abdulkarim D., Naoyuki Ebine, Satoshi Nakae, Tatsuya Hojo, and Yoshiyuki Fukuoka. "Application of Molecular Hydrogen as an Antioxidant in Responses to Ventilatory and Ergogenic Adjustments during Incremental Exercise in Humans." Nutrients 13, no. 2 (January 30, 2021): 459. http://dx.doi.org/10.3390/nu13020459.
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We investigated effects of molecular hydrogen (H2) supplementation on acid-base status, pulmonary gas exchange responses, and local muscle oxygenation during incremental exercise. Eighteen healthy, trained subjects in a randomized, double-blind, crossover design received H2-rich calcium powder (HCP) (1500 mg/day, containing 2.544 µg/day of H2) or H2-depleted placebo (1500 mg/day) for three consecutive days. They performed cycling incremental exercise starting at 20-watt work rate, increasing by 20 watts/2 min until exhaustion. Breath-by-breath pulmonary ventilation (V˙E) and CO2 output (V˙CO2) were measured and muscle deoxygenation (deoxy[Hb + Mb]) was determined via time-resolved near-infrared spectroscopy in the vastus lateralis (VL) and rectus femoris (RF). Blood gases’ pH, lactate, and bicarbonate (HCO3−) concentrations were measured at rest and 120-, 200-, and 240-watt work rates. At rest, the HCP group had significantly lower V˙E, V˙CO2, and higher HCO3−, partial pressures of CO2 (PCO2) versus placebo. During exercise, a significant pH decrease and greater HCO3− continued until 240-watt workload in HCP. The V˙E was significantly lower in HCP versus placebo, but HCP did not affect the gas exchange status of V˙CO2 or oxygen uptake (V˙O2). HCP increased absolute values of deoxy[Hb + Mb] at the RF but not VL. Thus, HCP-induced hypoventilation would lead to lower pH and secondarily impaired balance between O2 delivery and utilization in the local RF during exercise, suggesting that HCP supplementation, which increases the at-rest antioxidant potential, affects the lower ventilation and pH status during incremental exercise. HPC induced a significantly lower O2 delivery/utilization ratio in the RF but not the VL, which may be because these regions possess inherently different vascular/metabolic control properties, perhaps related to fiber-type composition.
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Fukuzawa, Hideya, Sarami Ishida, and Shigetoh Miyachi. "cDNA cloning and gene expression of carbonic anhydrase in Chlamydomonas reinhardtii." Canadian Journal of Botany 69, no. 5 (May 1, 1991): 1088–96. http://dx.doi.org/10.1139/b91-139.
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cDNA and genes encoding periplasmic carbonic anhydrase (CA) polypeptides of Chlamydomonas reinhardtii have been isolated and characterized. Nucleotide sequence analysis of cDNA clones revealed that the large subunit (35 kDa or 36.5 kDa) and the small subunit (4 kDa) are cotranslated as a precursor polypeptide (41 626 Da) with a NH2-terminal hydrophobic signal peptide of 20 amino acids. The amino acid sequence of Chlamydomonas CA showed 20–22% identity with animal CA isozymes (CAI, CAII, CAIII, and CAVII). Three zinc-liganded histidine residues and those forming the hydrogen-bond network to zinc-bound solvent molecules were highly conserved. No significant sequence similarity was observed between Chlamydomonas CA and chloroplast CAs of spinach and pea. Two copies of structurally related CA genes (CAH1 and CAH2) were tandemly clustered in Chlamydomonas nuclear genome and regulated by external CO2 concentration in a reverse manner. The 5′ upstream gene CAH1 encodes the major periplasmic CA whose mRNA level is induced under low CO2 condition in light. Photosynthesis is absolutely required for the accumulation of the CAH1 mRNA. The 3′ downstream gene CAH2 is possibly a gene for another periplasmic CA isozyme, which is induced under high CO2 conditions. Light has an inhibitory effect on the accumulation of the CAH2 mRNA. Key words: photosynthesis, light regulation, zinc, CO2-concentrating mechanism, intracellular processing.
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T-Raissi, A., N. Muradov, C. Huang, and O. Adebiyi. "Hydrogen From Solar Via Light-Assisted High-Temperature Water Splitting Cycles." Journal of Solar Energy Engineering 129, no. 2 (April 19, 2006): 184–89. http://dx.doi.org/10.1115/1.2710493.
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Hydrogen production from solar-driven thermochemical water splitting cycles (TCWSCs) provides an approach that is energy efficient and environmentally attractive. Of particular interest are TCWSCs that utilize both thermal (i.e., high temperature) and light (i.e., quantum) components of the solar resource, boosting the overall solar-to-hydrogen conversion efficiency compared to those with heat-only energy input. We have analyzed two solar-driven TCWSCs: (1) carbon dioxide (CO2)/carbon monoxide cycle; and (2) sulfur dioxide (SO2)/sulfuric acid cycle. The first cycle is based on the premise that CO2 becomes susceptible to near-ultraviolet and even visible radiation at high temperatures (greater than 1300K). The second cycle is a modification of the well-known Westinghouse hybrid cycle, wherein the electrochemical step is replaced by a photocatalytic step. At the Florida Solar Energy Center (FSEC), a novel hybrid photo-thermochemical sulfur-ammonia (S–A) cycle has been developed. The main reaction (unique to FSEC’s S–A cycle) is the light-induced photocatalytic production of hydrogen and ammonium sulfate from an aqueous ammonium sulfite solution. Ammonium sulfate product is processed to generate oxygen and recover ammonia and SO2 that are then recycled and reacted with water to regenerate the ammonium sulfite. Experimental data for verification of the concept are provided.
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Stanley, A. E., R. A. Johnson, J. B. Turner, and A. H. Roberts. "FT-IR Analysis of the Photolytic Laser-Induced Chemical Vapor Deposition of Germanium Films." Applied Spectroscopy 40, no. 3 (March 1986): 374–78. http://dx.doi.org/10.1366/0003702864509259.
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Germanium and doped-germanium polycrystalline films were formed with the use of photolytic CO2 laser-induced chemical vapor deposition. The compounds which yielded germanium in large quantities were germane, ethylgermane, and diethylgermane. Triethylgermane produces germanium in trace quantities. Gas-phase reactions were monitored with the use of Fourier transform infrared spectroscopy, also used for identification of end products. Scanning electron microscopy was used for analysis of the films. The products identified on irradiation of germane were germanium and hydrogen, with conversion rates of 86%. On irradiation of diethylgermane and ethylgermane, ethylene, germane, germanium, and hydrogen were produced. Germanium films doped with cadmium and aluminum were produced successfully by the irradiation of germane mixtures containing dimethylcadmium or trimethylaluminum, respectively.
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Fu, Wang, Liu, Bai, Liao, He, and Wang. "Recent Progress in Fabrications and Applications of Heating-Induced Long Period Fiber Gratings." Sensors 19, no. 20 (October 15, 2019): 4473. http://dx.doi.org/10.3390/s19204473.
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This paper presents a review of our work concerning the recent progress in fabrications and applications of heating-induced long period fiber gratings (LPFGs). Firstly, three kinds of heating fabrication techniques based on CO2 laser, hydrogen–oxygen flame and arc discharge are demonstrated to fabricate LPFGs, i.e., standard LPFGs (SLPFGs) and helical LPFGs (HLPFGs), in different types of optical fibers such as conventional fibers, photonic crystal fibers, and photonic bandgap fibers. Secondly, the all-fiber orbital angular momentum (OAM) mode converters based on heating-induced SLPFGs and HLPFGs in different types of fibers are studied to increase the transmission capacity. Finally, the heating-induced SLPFGs and HLPFGs are investigated to develop various LPFG-based strain, pressure, torsion and biochemical sensors.
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Qiu Zongbo, 邱宗波, 史静 Shi Jing, 张梦梦 Zhang Mengmeng, 于荣山 Yu Rongshan, and 岳明 Yue Ming. "Effect of Hydrogen Peroxide on CO2 Laser Pretreatment InducedDrought Tolerance in Wheat Seedlings." Chinese Journal of Lasers 37, no. 8 (2010): 2170–76. http://dx.doi.org/10.3788/cjl20103708.2170.
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Liu, Xiaozhan, Lu Zhao, Ying Li, Kegong Fang, and Minghong Wu. "Ni-Mo Sulfide Semiconductor Catalyst with High Catalytic Activity for One-Step Conversion of CO2 and H2S to Syngas in Non-Thermal Plasma." Catalysts 9, no. 6 (June 12, 2019): 525. http://dx.doi.org/10.3390/catal9060525.
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Carbon dioxide (CO2) and hydrogen sulfide (H2S) ordinarily coexist in many industries, being considered as harmful waste gases. Simultaneously converting CO2 and H2S into syngas (a mixture of CO and H2) will be a promising economic strategy for enhancing their recycling value. Herein, a novel one-step conversion of CO2 and H2S to syngas induced by non-thermal plasma with the aid of Ni-Mo sulfide/Al2O3 catalyst under ambient conditions was designed. The as-synthesized catalysts were characterized by using XRD, nitrogen sorption, UV-vis, TEM, SEM, ICP, and XPS techniques. Ni-Mo sulfide/Al2O3 catalysts with various Ni/Mo molar ratios possessed significantly improved catalytic performances, compared to the single-component catalysts. Based on the modifications of the physical and chemical properties of the Ni-Mo sulfide/Al2O3 catalysts, the variations in catalytic activity are carefully discussed. In particular, among all the catalysts, the 5Ni-3Mo/Al2O3 catalyst exhibited the best catalytic behavior with high CO2 and H2S conversion at reasonably low-energy input in non-thermal plasma. This method provides an alternative route for syngas production with added environmental and economic benefits.
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Shi, Kai, Xin Li, Huan Zhang, Guanqun Zhang, Yaru Liu, Yanhong Zhou, Xiaojian Xia, Zhixiang Chen, and Jingquan Yu. "Guard cell hydrogen peroxide and nitric oxide mediate elevated CO2-induced stomatal movement in tomato." New Phytologist 208, no. 2 (August 26, 2015): 342–53. http://dx.doi.org/10.1111/nph.13621.
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Liu, Hongfei, Jun Xia, Nan Zhang, Han Cheng, Wentuan Bi, Xiaolong Zu, Wangsheng Chu, HengAn Wu, Changzheng Wu, and Yi Xie. "Solid–liquid phase transition induced electrocatalytic switching from hydrogen evolution to highly selective CO2 reduction." Nature Catalysis 4, no. 3 (March 2021): 202–11. http://dx.doi.org/10.1038/s41929-021-00576-3.
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Lie, Zener Sukra, Ali Khumaeni, Tadashi Maruyama, Ken-ichi Fukumoto, Hideaki Niki, and Kiichiro Kagawa. "Emission characteristics of hydrogen in atmospheric helium gas plasma induced by TEA CO2 laser bombardment on zircaloy sample containing hydrogen." Journal of Analytical Atomic Spectrometry 26, no. 7 (2011): 1451. http://dx.doi.org/10.1039/c0ja00193g.
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Fortunato, Anna, and Miriam Mba. "Metal Cation Triggered Peptide Hydrogels and Their Application in Food Freshness Monitoring and Dye Adsorption." Gels 7, no. 3 (July 7, 2021): 85. http://dx.doi.org/10.3390/gels7030085.
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Metal-ligand interactions have emerged as an important tool to trigger and modulate self-assembly, and to tune the properties of the final supramolecular materials. Herein, we report the metal-cation induced self-assembly of a pyrene–peptide conjugate to form hydrogels. The peptide has been rationally designed to favor the formation of β-sheet 1D assemblies and metal coordination through the Glu side chains. We studied in detail the self-assembly process in the presence of H+, Li+, Na+, K+, Ca2+, Ni2+, Cu2+, Zn2+, Cd2+, Co2+, Fe3+, and Cr3+ and found that the morphology and mechanical properties of the hydrogels are ion-dependent. Moreover, thanks to the presence of the metal, new applications could be explored. Cu2+ metallogels could be used for amine sensing and meat freshness monitoring, while Zn2+ metallogels showed good selectivity for cationic dye adsorption and separation.
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Hagens, M., C. P. Slomp, F. J. R. Meysman, D. Seitaj, J. Harlay, A. V. Borges, and J. J. Middelburg. "Biogeochemical processes and buffering capacity concurrently affect acidification in a seasonally hypoxic coastal marine basin." Biogeosciences 12, no. 5 (March 11, 2015): 1561–83. http://dx.doi.org/10.5194/bg-12-1561-2015.
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Abstract. Coastal areas are impacted by multiple natural and anthropogenic processes and experience stronger pH fluctuations than the open ocean. These variations can weaken or intensify the ocean acidification signal induced by increasing atmospheric pCO2. The development of eutrophication-induced hypoxia intensifies coastal acidification, since the CO2 produced during respiration decreases the buffering capacity in any hypoxic bottom water. To assess the combined ecosystem impacts of acidification and hypoxia, we quantified the seasonal variation in pH and oxygen dynamics in the water column of a seasonally stratified coastal basin (Lake Grevelingen, the Netherlands). Monthly water-column chemistry measurements were complemented with estimates of primary production and respiration using O2 light–dark incubations, in addition to sediment–water fluxes of dissolved inorganic carbon (DIC) and total alkalinity (TA). The resulting data set was used to set up a proton budget on a seasonal scale. Temperature-induced seasonal stratification combined with a high community respiration was responsible for the depletion of oxygen in the bottom water in summer. The surface water showed strong seasonal variation in process rates (primary production, CO2 air–sea exchange), but relatively small seasonal pH fluctuations (0.46 units on the total hydrogen ion scale). In contrast, the bottom water showed less seasonality in biogeochemical rates (respiration, sediment–water exchange), but stronger pH fluctuations (0.60 units). This marked difference in pH dynamics could be attributed to a substantial reduction in the acid–base buffering capacity of the hypoxic bottom water in the summer period. Our results highlight the importance of acid–base buffering in the pH dynamics of coastal systems and illustrate the increasing vulnerability of hypoxic, CO2-rich waters to any acidifying process.
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Hagens, M., C. P. Slomp, F. J. R. Meysman, D. Seitaj, J. Harlay, A. V. Borges, and J. J. Middelburg. "Biogeochemical processes and buffering capacity concurrently affect acidification in a seasonally hypoxic coastal marine basin." Biogeosciences Discussions 11, no. 11 (November 18, 2014): 15827–87. http://dx.doi.org/10.5194/bgd-11-15827-2014.
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Abstract. Coastal areas are impacted by multiple natural and anthropogenic processes and experience stronger pH fluctuations than the open ocean. These variations can weaken or intensify the ocean acidification signal induced by increasing atmospheric pCO2. The development of eutrophication-induced hypoxia intensifies coastal acidification, since the CO2 produced during respiration decreases the buffering capacity of the hypoxic bottom water. To assess the combined ecosystem impacts of acidification and hypoxia, we quantified the seasonal variation in pH and oxygen dynamics in the water column of a seasonally stratified coastal basin (Lake Grevelingen, the Netherlands). Monthly water column chemistry measurements were complemented with estimates of primary production and respiration using O2 light-dark incubations, in addition to sediment-water fluxes of dissolved inorganic carbon (DIC) and total alkalinity (TA). The resulting dataset was used to set up a proton budget on a seasonal scale. Temperature-induced seasonal stratification combined with a high community respiration was responsible for the depletion of oxygen in the bottom water in summer. The surface water showed strong seasonal variation in process rates (primary production, CO2 air–sea exchange), but relatively small seasonal pH fluctuations (0.46 units on the total hydrogen ion scale). In contrast, the bottom water showed less seasonality in biogeochemical rates (respiration, sediment–water exchange), but stronger pH fluctuations (0.60 units). This marked difference in pH dynamics could be attributed to a substantial reduction in the acid-base buffering capacity of the hypoxic bottom water in the summer period. Our results highlight the importance of acid-base buffering in the pH dynamics of coastal systems and illustrate the increasing vulnerability of hypoxic, CO2-rich waters to any acidifying process.
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Kovács, Viktória, Gábor Remzső, Valéria Tóth-Szűki, Viktória Varga, János Németh, and Ferenc Domoki. "Inhaled H2 or CO2 Do Not Augment the Neuroprotective Effect of Therapeutic Hypothermia in a Severe Neonatal Hypoxic-Ischemic Encephalopathy Piglet Model." International Journal of Molecular Sciences 21, no. 18 (September 16, 2020): 6801. http://dx.doi.org/10.3390/ijms21186801.
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Hypoxic-ischemic encephalopathy (HIE) is still a major cause of neonatal death and disability as therapeutic hypothermia (TH) alone cannot afford sufficient neuroprotection. The present study investigated whether ventilation with molecular hydrogen (2.1% H2) or graded restoration of normocapnia with CO2 for 4 h after asphyxia would augment the neuroprotective effect of TH in a subacute (48 h) HIE piglet model. Piglets were randomized to untreated naïve, control-normothermia, asphyxia-normothermia (20-min 4%O2–20%CO2 ventilation; Tcore = 38.5 °C), asphyxia-hypothermia (A-HT, Tcore = 33.5 °C, 2–36 h post-asphyxia), A-HT + H2, or A-HT + CO2 treatment groups. Asphyxia elicited severe hypoxia (pO2 = 19 ± 5 mmHg) and mixed acidosis (pH = 6.79 ± 0.10). HIE development was confirmed by altered cerebral electrical activity and neuropathology. TH was significantly neuroprotective in the caudate nucleus but demonstrated virtually no such effect in the hippocampus. The mRNA levels of apoptosis-inducing factor and caspase-3 showed a ~10-fold increase in the A-HT group compared to naïve animals in the hippocampus but not in the caudate nucleus coinciding with the region-specific neuroprotective effect of TH. H2 or CO2 did not augment TH-induced neuroprotection in any brain areas; rather, CO2 even abolished the neuroprotective effect of TH in the caudate nucleus. In conclusion, the present findings do not support the use of these medical gases to supplement TH in HIE management.
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Takashima, Toshihiro, Yukitaka Fujishiro, and Hiroshi Irie. "Noble Metal Modification of CdS-Covered CuInS2 Electrodes for Improved Photoelectrochemical Activity and Stability." Catalysts 10, no. 9 (August 20, 2020): 949. http://dx.doi.org/10.3390/catal10090949.
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In this paper, efficient and stable photoelectrochemical (PEC) hydrogen (H2) evolution using copper indium sulfide (CuInS2) thin film electrodes was studied. Modification with a cadmium sulfide (CdS) layer led to improved charge separation at the interface between CuInS2 and CdS; however, the photocorrosive nature of CdS induced poor stability of the photocathode. Further surface coating with an electrodeposited Pt layer over the CdS-covered CuInS2 photocathode prevented the CdS layer from making contact with the electrolyte solution, and enabled efficient PEC H2 evolution without appreciable degradation. This indicates that the Pt layer functioned not only as a reaction site for H2 evolution, but also as a protection layer. In addition, it was found that surface protection using a noble metal layer was also effective for stable PEC carbon dioxide (CO2) reduction when appropriate noble metal cocatalysts were selected. When Au or Ag was used, carbon monoxide was obtained as a product of PEC CO2 reduction.
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Abas, Ahmad Zaki, Azmi Mohammed Nor, Muhammad Firdaus Suhor, Ahmad Mustaza Ahmad Rusli, and Mokhtar Che Ismail. "HIC and SSC of Carbon Steel in High Partial Pressure CO2 Environments with Elevated H2S." E3S Web of Conferences 287 (2021): 02001. http://dx.doi.org/10.1051/e3sconf/202128702001.
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The Hydrogen Induced Cracking (HIC) and Sulfide Stress Cracking (SSC) behaviours of sour service and non-sour service carbon steel API 5L X65 were investigated under high pressure carbon dioxide environments, containing elevated amount of hydrogen sulphide (H2S); the test environments simulated offshore pipelines transporting full-well streams in high carbon dioxide (CO2) environments with elevated H2S concentrations. It was systematically studied under standard NACE condition and high pressure carbon dioxide field condition with variation in other key parameters (temperature, pressure and hydrogen sulfide concentration). The HIC and SSC were tested using a High Pressure and High Temperature (HPHT) Autoclave. The surface cracking morphology was analysed using Scanning Electron Microscopy (SEM), Ultrasonic Technique (UT) and Magnetic Particle (MP). The results showed that no cracks were detected in NACE standard and field-condition SSC tests for both sour service and non-sour services carbon steel. In HIC test, crack was detected on non-sour service carbon steel in NACE standard test while no crack was detected on field condition-based tests for both types of carbon steel.
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Neubauer, Christian, and Ulrich Schreiber. "Photochemical and Non-Photochemical Quenching of Chlorophyll Fluorescence Induced by Hydrogen Peroxide." Zeitschrift für Naturforschung C 44, no. 3-4 (April 1, 1989): 262–70. http://dx.doi.org/10.1515/znc-1989-3-415.
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Abstract Chlorophyll Fluorescence. Fluorescence Quenching, Hydrogen Peroxide. Active Oxygen. Ascorbate Peroxidase Chlorophyll fluorescence quenching induced by H 20 2 in intact spinach chloroplasts was investigated with a modulation fluorometer which allows to distinguish between photochemical and non photochemical quenching components by the so-called saturation pulse method. Residual catalase activity was removed by washing and percoll gradient centrifugation. H2O2 was found to induce pronounced photochem ical and non-photochemical quenching, characteristic for the action of a Hill reagent, with a half-maximal rate already observed at 5 × 10-6 m . The saturation characteristics and maximal rate of H2O2-reduction were very similar to those of methylviologen reduction. H2O2-dependent quenching was stimulated by ascorbate and inhibited by cyanide and azide in agreement with previous findings by other researchers that H2O2-reduction involves the ascorbate peroxidase scavenging system and that the actual “Hill acceptor” is an oxidation product of ascorbate, i.e. monodehydroascorbate or dehydroascorbate. With well-coupled intact chloroplasts reducing CO2 at 150 (μmol (mg Chl)-1h-1, iodoacetamide stopped CO2-dependent O2-evolution and consequent addition of 10″3 m H2O2 produced an O2-Solution rate of 240 (μmol (mg Chl)-1h-1 .It is concluded that light-dependent H 20 2 reduction is a very efficient reaction in intact chloroplasts. As H2O2 formation and consequent reduction also occur in vivo, the corresponding quenching should be considered when assimilatory electron flow is estimated from quenching coefficients. It is suggested that proton flux associated with H2O2-formation and reduction may be important for the adjustment of appropriate ATP /NADPH ratios required for CO2-fixation in vivo. Furthermore, H2O2-reduction may serve as a valve reaction whenever Calvin cycle activity is limited by factors different from NADPH supply, thus protecting against photo-inhibitory damage.
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Le Hien, Nguyen Thi. "CRACKING CORROSION OF LOW CARBON STEEL IN ENVIRONMENT WITH A HIGH CONCENTRATION OF CO2 AND H2S." Vietnam Journal of Science and Technology 55, no. 5B (March 24, 2018): 210. http://dx.doi.org/10.15625/2525-2518/55/5b/12228.
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Cracking corrosion of API 5CT Grade L80 Type 1 low carbon steel has been studied in a in brine solutions with H2S 12.3 psia and CO2 9.4 psia. Testing was performed according to the methodology reference from the NACE TM0177, Bent-beam test method in solution B for stress corrosion cracking and sulfide stress corrosion cracking test and NACE TM0284, immersion test method in solution A for Hydrogen induced cracking test.The obtained results showed pitting and general corrosion at both temperatures of 24 oC and 82 oC. In case of stress corrosion cracking (SCC) testing at 82 °C, microscopy of the samples tested for 30 days developed pitting corrosion in the surface and cracking starting in the surface of the samples. The cracks, mostly found in the middle of the samples where the maximum bending occurred. General corrosion was also observed in the samples, with significant decrease in the dimensions of the samples after testing (due to general corrosion). However, in case of sulfide stress corrosion (SSC) and hydrogen induced cracking (HIC) tests at room temperature (24-25 oC), no cracking was observed on the sample.
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Tantawy, Waled, Ahmed Hashem, Nabil Yousif, and Eman Flefel. "The water–boryl radical as a proton-coupled electron transfer reagent for carbon dioxide, formic acid, and formaldehyde — Theoretical approach." Canadian Journal of Chemistry 91, no. 2 (February 2013): 155–68. http://dx.doi.org/10.1139/cjc-2012-0303.
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The thermochemistry of the hydrogen atom transfer reactions from the H2O–BX2 radical system (X = H, CH3, NH2, OH, F) to carbon dioxide, formic acid, and (or) formaldehyde, which produce hydroxyformyl, dihydroxymethyl, and hydroxymethyl radicals, respectively, were investigated theoretically at ROMP2/6–311+G(3DF,2P)//UB3LYP/6–31G(D) and UG3(MP2)-RAD levels of theory. Surprisingly, in the cases of a strong Lewis acid (X = H, CH3, F), the spin transfer process from the water–boryl radical to the carbonyl compounds was barrier-free and associated with a dramatic reduction in the B–H bond dissociation energy (BDE) relative to that of isolated water–borane complexes. Examining the coordinates of these reactions revealed that the entire hydrogen atom transfer process is governed by the proton-coupled electron transfer (PCET) mechanism. Hence, the elucidated mechanism has been applied in the cases of weak Lewis acids (X = NH2, OH), and the variation in the accompanied activation energy was attributed to the stereoelectronic effect interplaying in CO2 and HCOOH compared with HCHO. We ascribed the overall mechanism as a SA-induced five-center cyclic PCET, in which the proton transfers across the so-called complexation-induced hydrogen bond (CIHB) channel, while the SOMOB–LUMOC=O′ interaction is responsible for the electron migration process. Owing to previous reports that interrelate the hydrogen-bonding and the rate of proton-coupled electron-transfer reactions, we postulated that “the rate of the PCET reaction is expected to be promoted by the covalency of the hydrogen bond, and any factor that enhances this covalency could be considered an activator of the PCET process.” This postulate could be considered a good rationale for the lack of a barrier associated with the hydrogen atom transfer from the water-boryl radical system to the carbonyl compounds. Light has been shed on the water–boryl radical reagent from the thermodynamic perspective.
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Srinivas, G., V. Sankaranarayanan, and S. Ramaprabhu. "Hydrogen-induced and A-site substitution-dependent structural properties of AB2-type (Ho1−xAx)Co2–hydrogen system (A=Mm and Ti)." Journal of Alloys and Compounds 458, no. 1-2 (June 2008): 574–78. http://dx.doi.org/10.1016/j.jallcom.2007.04.210.
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Kim, Yeonwoo, Tran Si Bui Trung, Sena Yang, Sehun Kim, and Hangil Lee. "Mechanism of the Surface Hydrogen Induced Conversion of CO2 to Methanol at Cu(111) Step Sites." ACS Catalysis 6, no. 2 (January 12, 2016): 1037–44. http://dx.doi.org/10.1021/acscatal.5b02083.
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Rakitzis, Emmanuel T. "Thermodynamic considerations of arteriovenous gradients of hydrogen ion concentration and carbon dioxide tension." Annals of Clinical Biochemistry: International Journal of Laboratory Medicine 37, no. 2 (March 1, 2000): 114–18. http://dx.doi.org/10.1258/0004563001899096.
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It is shown that, in a multicompartmental homeostatic system, the extent of interaction between any two compartments can be assessed by determination of the difference in free energy change of one particular reaction, or a series of coupled reactions, operative in both of the compartments under consideration. Hydrogen ion concentration and carbon dioxide tension have been used to determine free energy change difference relationships between the venous and arterial compartments (- G(a-v)) of the circulatory system. Data from the literature (from two studies of congestive heart failure and one study of experimentally induced cardiac arrest) are used to calculate - G(a-v). It was found that in control subjects - G(a-v) is close to zero, whereas in congestive heart failure or cardiac arrest, the value rises to 150 calmol-1 or more, whereas in blood, the approach towards equilibrium between hydrogen and bicarbonate ions and dissolved carbon dioxide (aqueous CO2) is known to be only moderately rapid. It is concluded that, in the system under study, and with respect to the reaction H+ + HCO3- = CO2 + H2O, a high value for the free energy change difference between the two compartments (high - G(a-v)) must be due to an insufficient blood circulation rate. Accordingly, - G(a-v) is probably a quantitative measure of cardiac insufficiency.
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BASHIR, SHAZIA, M. SHAHID RAFIQUE, and FAIZAN UL-HAQ. "Laser ablation of ion irradiated CR-39." Laser and Particle Beams 25, no. 1 (February 28, 2007): 181–91. http://dx.doi.org/10.1017/s0263034607070231.
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The effects of multiple pulses of a CO2 laser with energy of 2.5 J and pulse duration of 200 ns on the surface morphology of ion irradiated CR-39 is investigated in light of the modification in its track registration properties. For this purpose, a CR-39 was exposed by a CO2 laser generated hydrogen, argon, cadmium, air molecular ions (N2 and O2, etc.), high energy (300 KeV) proton beam from Cock Croft Walton accelerator, and α (5 MeV) from 0.5 μCi Pu239 source. The registered tracks were enlarged after 6 h of 6.25 N NaOH etching. These etched detectors were then exposed to different number of CO2 laser shots. The etched detectors were then analyzed by a computer controlled optical microscope (Lexica DMR series). It was observed that even a single shot of CO2 laser, irrespective of the registered ions tracks, can change the track registration properties of CR-39, and can remove the vaporization resistant skin present on the polymer (CR-39). A significant change in track density and track shaping regardless of the ions is observed. At the outside of the focal area, the ion density of different registered tracks is compared graphically before and after laser irradiation. Laser ablation of unexposed CR-39 is also done with multiple pulses CO2 laser. In this regard, the coherent and non-coherent structures, diffraction patterns, circular fringes with corrugations and ripples, droplets, chain like structures with cluster formation, chain folded crystallites, and hole drilling were observed. The irradiation induced ablation of the polymer is of great importance in electronics industry, lithography, etc.
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Adler, S., J. G. Verbalis, and D. Williams. "Brain buffering is restored in hyponatremic rats by correcting their plasma sodium concentration." Journal of the American Society of Nephrology 5, no. 1 (July 1994): 85–92. http://dx.doi.org/10.1681/asn.v5185.
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Previous studies from this laboratory showed that both acute and chronic hyponatremia impaired active brain buffering. These studies were performed to determine whether correcting the plasma sodium restored normal buffering in hyponatremic rats. Acute (1- and 2-day) and chronic (7- and 14-day) hyponatremia was induced in male Sprague-Dawley rats by constant desmopressin administration combined with a liquid diet. Plasma sodium was corrected by stopping desmopressin for 6 h, substituting solid chow, and allowing free access to water. Studies were performed 24 h later. Uncorrected hyponatremic rats who continued to receive desmopressin and liquid diet served as controls. Brain pH was determined by [31P]NMR in rats anesthetized with N2O and paralyzed with pancuronium. Brain buffering was determined by the response to CO2 loading. Resting brain pH was the same in corrected and uncorrected rats, but the two groups responded differently to CO2 loading. Thus, 55 min after ventilation with 20% CO2, corrected rat brain pH was 0.13 pH units higher than in uncorrected rats despite statistically similar changes in CO2 tension and arterial pH in both groups. Moreover, 15 min into recovery from CO2 exposure, brain pH in corrected rats overshot resting pH by 0.07, whereas no overshoot occurred in uncorrected rats. Buffering in corrected rats was identical to that shown previously in normonatremic rats. The complete restoration of late-phase buffering achieved by normalizing the plasma sodium of hyponatremic rats indicates that at least some portion of active hydrogen ion transport is sodium dependent in the brain.
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Peksen, Murat. "Hydrogen Technology towards the Solution of Environment-Friendly New Energy Vehicles." Energies 14, no. 16 (August 10, 2021): 4892. http://dx.doi.org/10.3390/en14164892.
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The popularity of climate neutral new energy vehicles for reduced emissions and improved air quality has been raising great attention for many years. World-wide, a strong commitment continues to drive the demand for zero-emission through alternative energy sources and propulsion systems. Despite the fact that 71.27% of hydrogen is produced from natural gas, green hydrogen is a promising clean way to contribute to and maintain a climate neutral ecosystem. Thereby, reaching CO2 targets for 2030 and beyond requires cross-sectoral changes. However, the strong motivation of governments for climate neutrality is challenging many sectors. One of them is the transport sector, as it is challenged to find viable all-in solutions that satisfy social, economic, and sustainable requirements. Currently, the use of new energy vehicles operating on green sustainable hydrogen technologies, such as batteries or fuel cells, has been the focus for reducing the mobility induced emissions. In Europe, 50% of the total emissions result from mobility. The following article reviews the background, ongoing challenges and potentials of new energy vehicles towards the development of an environmentally friendly hydrogen economy. A change management process mindset has been adapted to discuss the key scientific and commercial challenges for a successful transition.
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Lin, Ruei-Lung, Qihai Gu, You-Shuei Lin, and Lu-Yuan Lee. "Stimulatory effect of CO2 on vagal bronchopulmonary C-fiber afferents during airway inflammation." Journal of Applied Physiology 99, no. 5 (November 2005): 1704–11. http://dx.doi.org/10.1152/japplphysiol.00532.2005.
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This study investigated 1) whether pulmonary C fibers are activated by a transient increase in the CO2 concentration of alveolar gas; and 2) if the CO2 sensitivity of these afferents is altered during airway inflammation. Single-unit pulmonary C-fiber activity was recorded in anesthetized, open-chest rats. Transient alveolar hypercapnia (HPC) was induced by administering a CO2-enriched gas mixture (25–30% CO2, 21% O2, balance N2) for five to eight breaths, which increased alveolar CO2 concentration progressively to near or above 13% for 3–5 s and lowered the arterial pH transiently to 7.10 ± 0.05. Our results showed the following. 1) HPC evoked only a mild stimulation in a small fraction (4/47) of pulmonary C fibers, and there was no significant change in fiber activity (change in fiber activity = 0.22 ± 0.16 imp/s; P > 0.1, n = 47). 2) In sharp contrast, after airway exposure to poly-l-lysine, a cationic protein known to induce mucosal injury, the same challenge of transient HPC activated 87.5% of the pulmonary C fibers tested and evoked a distinct stimulatory effect on these afferents (change in fiber activity = 6.59 ± 1.78 imp/s; P < 0. 01, n = 8). 3) Similar potentiation of the C-fiber response to HPC was also observed after acute exposure to ozone ( n = 6) and during a constant infusion of inflammatory mediators such as adenosine ( n = 15) or prostaglandin E2 ( n = 12). 4) The enhanced C-fiber sensitivity to CO2 after poly-l-lysine was completely abrogated by infusion of NaHCO3 (1.82 mmol·kg−1·min−1) that prevented the reduction in pH during HPC ( n = 6). In conclusion, only a small percentage (<10%) of the bronchopulmonary C fibers exhibit CO2 sensitivity under control conditions, but alveolar HPC exerts a consistent and pronounced stimulatory effect on the C-fiber endings during airway inflammation. This effect of CO2 is probably mediated through the action of hydrogen ions.
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Timonen, Juri, Paula Aulaskari, Pipsa Hirva, and Pirjo Vainiotalo. "Negative Ion Electrospray Ionization Mass Spectrometry and Computational Studies on Substituted 7-Hydroxycoumarins." European Journal of Mass Spectrometry 15, no. 5 (October 2009): 595–603. http://dx.doi.org/10.1255/ejms.1019.
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Twenty-two substituted 7-hydroxycoumarins were studied by negative ion electrospray ionization collision-induced dissociation (CID) mass spectrometry. Fragmentation pathways were also investigated by computation method using the B3LYP density functional theory. In general, the most important fragmentations of the 7-hydroxycoumarin [M – H]− ions were the elimination of CO2 and CO which agreed with the calculated energies of the proposed fragmentation reactions. In most cases, methyl group elimination was also favorable. Methyl group elimination occurred in three different ways, the most interesting being hydrogen rearrangement from a neighboring alkyl group to a ring carbon, which led to a benzyl radical formation. In some cases, CH2CO elimination was observed as well. Isomeric compounds gave rise to different CID spectra.
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FURNES, HARALD, KARLIS MUEHLENBACHS, TERJE TORSVIK, OLE TUMYR, and LANG SHI. "Bio-signatures in metabasaltic glass of a Caledonian ophiolite, West Norway." Geological Magazine 139, no. 6 (November 2002): 601–8. http://dx.doi.org/10.1017/s0016756802006830.
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Evidence of bioalteration of natural basaltic rocks, presently receiving much attention, has so far been restricted to in situ oceanic crust and ophiolites in which fresh glass is still present. Here we present evidence of preserved bio-signatures in the chilled margin of pillow lavas of an old (443 Ma) ophiolite that has suffered pervasive lower greenschist facies metamorphism and deformation. X-ray mapping of initial alteration zones shows the remains of organic carbon associated with highly-concentrated Fe and S. Bioproduction of CO2 is further reflected in the low δ13C values of calcite extracted from pillow rims, compatible with microbe-induced fractionation during oxidation of organic matter. We attribute these effects to growth of sulphate-reducing bacteria at the early stage of ophiolite formation. During energy metabolism these bacteria reduce sulphate to H2S and oxidize organic matter to CO2 . Hydrogen sulphide will eventually react with iron and form pyrite, and carbon dioxide is precipitated as calcium carbonate. The results of this study may thus trigger the search for bio-signatures in glassy volcanic rocks of any age.
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Khumaeni, Ali, Wahyu S. Budi, Asep Y. Wardaya, Hideaki Niki, Kazuyoshi Kurihara, and Kiichiro Kagawa. "Emission Characteristics of Hydrogen and Carbon in Various Ambient Gases using Pulsed-CO2 Laser-Induced Breakdown Spectroscopy." Current Analytical Chemistry 16, no. 3 (May 15, 2020): 234–40. http://dx.doi.org/10.2174/1573411014666181115121139.
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Background: Hydrogen (H) and Carbon (C) are major elements that occur in various materials, including organic matter. The identification and analysis of C and H are necessary for several fields. LIBS is an excellent method for such analysis because it is rapid, and can be conducted remotely. The technique has been employed for the analysis of H in zircaloy metals. However, few studies on the emission characteristics of H and C in various gases have been undertaken because of the difficulty of identifying H and C using standard LIBS techniques. In this work, the emission characteristics of H and C were studied using pulsed CO2 LIBS. H and C elements were obtained from ethanol vapor. Various gas environments were employed, including Nitrogen (N2), Argon (Ar), and Helium (He) gases, in order to study the stability of the laser-induced plasma, the plasma lifetime, and the excitation mechanisms of H and C. Methods: The LIBS system used in this work consisted of a pulsed TEA CO2 laser (Shibuya SQ 2000), pulse generator, and optical multichannel analyzer. In this work, the laser with a wavelength of 10.6 µm, pulse duration of 200 ns, and pulse energy of 3 J, was used as the irradiation source. The laser energy used was 1.5 J. The laser was irradiated, and focused, using a 200 mm zinc selenide (ZnSe) lens, onto a metal surface in order to initiate and induce a luminous plasma. The sample used in this study was ethanol vapor, obtained from ethanol (99.5%, Merck). For this purpose, 10 mL ethanol was poured into a glass beaker, and this was placed into a closed chamber that could be evacuated by ambient gases including N2, Ar, and He gases. Results: Identification of H emission line has been successfully carried out using this present technique demonstrated in various gases including N2, Ar, and He. From the results, it was observed that in N2 gas, the Hα I 656.3 nm emission line was clearly expressed, with a wide, full-width halfmaximum, and quite a low emission intensity. Conclusion: The emission characteristics of H and C in laser-induced plasma, produced in various ambient gases, including N2, Ar, and He, were studied. The emission spectra of Hα and Hβ were expressed clearly, with high intensity and low background emission, in He, while they were broad and had high background emissions in N2 and Ar. Based on the time-resolved emissions, the Hα emission had a longer lifetime in Ar and He. It was assumed that the metastable atoms of Arand He were predominant in the excitation process of H and C. The characteristics of the H and C emissions in various gases are important in selecting a suitable ambient gas for the study of light atomic emission in the medical field, which mostly deals with organic materials containing H, C, and oxygen.
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Lie, Zener Sukra, Ali Khumaeni, Tadashi Maruyama, Ken-ichi Fukumoto, Hideaki Niki, and Kiichiro Kagawa. "Hydrogen analysis in metal samples by selective detection method utilizing TEA CO2 laser-induced He gas plasma." Applied Physics A 101, no. 3 (July 21, 2010): 555–58. http://dx.doi.org/10.1007/s00339-010-5897-4.
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Liu, Hongfei, Jun Xia, Nan Zhang, Han Cheng, Wentuan Bi, Xiaolong Zu, Wangsheng Chu, HengAn Wu, Changzheng Wu, and Yi Xie. "Publisher Correction: Solid–liquid phase transition induced electrocatalytic switching from hydrogen evolution to highly selective CO2 reduction." Nature Catalysis 4, no. 4 (April 2021): 342. http://dx.doi.org/10.1038/s41929-021-00608-y.
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Elisabetta Palumbo, Maria, Giuseppe A. Baratta, Gleb Fedoseev, Daniele Fulvio, Carlotta Scirè, Giovanni Strazzulla, and Riccardo Giovanni Urso. "Laboratory investigations aimed at building a database for the interpretation of JWST spectra." Proceedings of the International Astronomical Union 15, S350 (April 2019): 77–80. http://dx.doi.org/10.1017/s1743921319007609.
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AbstractThe James Webb Space Telescope (JWST) is expected to be launched in 2021. The JWST’s science instruments will provide high quality spectra acquired in the line of sight to young stellar objects whose interpretation will require a robust database of laboratory data. With this in mind, an experimental work is in progress in the Laboratory for Experimental Astrophysics in Catania to study the profile (shape, width, and peak position) of the main infrared bands of molecular species expected to be present in icy grain mantles. Our study also takes into account the modifications induced on icy samples by low-energy cosmic ray bombardment and by thermal processing. Here we present some recent results on deuterium hydrogen monoxide (HDO), N-bearing species, and carbon dioxide (CO2).
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BUCHALLA, RAINER, CHRISTIAN SCHÜTTLER, and KLAUS WERNER BÖGL. "Effects of Ionizing Radiation on Plastic Food Packaging Materials: A Review." Journal of Food Protection 56, no. 11 (November 1, 1993): 991–97. http://dx.doi.org/10.4315/0362-028x-56.11.991.
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Irradiation of prepackaged food causes chemical and physical changes in plastic packaging materials. The effects of ionizing radiation on these materials have been studied for almost 40 years; the respective literature is reviewed to provide the basis for a safety evaluation of plastics for use in food irradiation. Permeability of plastic films is generally not affected; deterioration of mechanical properties, that may occur with certain polymers, can usually be controlled with adequate stabilizers; and changes in infrared and UV/VIS spectra are slight at food irradiation doses. Gaseous radiolysis products include hydrogen, methane, CO2, CO, hydrocarbons, and for chlorine-containing polymers, hydrogen chloride. A range of volatile products, mainly hydrocarbons, alcohols, aldehydes, ketones, and carboxylic acids, has been characterized for low density polyethylene and polypropylene, other important materials, e.g., polystyrene and poly(vinyl chloride), are less well-investigated. Comparatively little is known on the effect of irradiation on multilayer structures. Radiation-induced changes are shown to depend on the chemical structure of the polymer, on the composition (additives) and processing history of the plastic, and on the irradiation conditions.