WorldWideScience

Sample records for program h2 incident

  1. [Can preoperative administration of H2 blocker reduce the incidence of postoperative nausea and vomiting (PONV)?].

    Science.gov (United States)

    Nozaki, Chisato; Morioka, Nobutada; Kinoshita, Maho; Takada, Mikiko; Ozaki, Makoto

    2007-10-01

    PONV is a complication that reduces a patient's quality of life (QOL). Recently, it was reported that PONV is reduced by preoperative administration of histamine receptor (H1 and H2) inhibitor. In the present study, based on the hypothesis that PONV might be reduced by preoperative administration of H2 blocker, we examined the effect of preoperative administration of H2 blocker only on the incidence of PONV. Eighty seven patients having regular operations were randomly assigned into two groups; the control (C), and the H2 blocker (F) groups. In the operating room, 20 min after intravenous injection of famotidine 20 mg as H2 blocker, anesthesia was maintened by sevofluorane, oxygen, nitrous oxide, and fentanyl following the induction by fentanyl, propofol, and vecuronium. The frequency and extent of vomiting were observed and the patients were interviewed at postoperative hours 0-6 and 6-12. The incidences between the two groups were examined using the chi-squared test. No significant difference in the appearance of PONV was found between the F group and the C group. In women in the F group, the incidence of vomiting was lower. Preoperative administration of H2 blocker tends to reduce PONV in women.

  2. NASA Lewis H2-O2 MHD program

    Science.gov (United States)

    Smith, M.; Nichols, L. D.; Seikel, G. R.

    1974-01-01

    Performance and power costs of H2-O2 combustion powered steam-MHD central power systems are estimated. Hydrogen gas is assumed to be transmitted by pipe from a remote coal gasifier into the city and converted to electricity in a steam MHD plant having an integral gaseous oxygen plant. These steam MHD systems appear to offer an attractive alternative to both in-city clean fueled conventional steam power plants and to remote coal fired power plants with underground electric transmission into the city. Status and plans are outlined for an experimental evaluation of H2-O2 combustion-driven MHD power generators at NASA Lewis Research Center.

  3. Relationship of body weight parameters with the incidence of common spontaneous tumors in Tg.rasH2 mice.

    Science.gov (United States)

    Paranjpe, Madhav G; Denton, Melissa D; Vidmar, Tom J; Elbekai, Reem H

    2014-10-01

    The mechanistic relationship between increased food consumption, increased body weights, and increased incidence of tumors has been well established in 2-year rodent models. Body weight parameters such as initial body weights, terminal body weights, food consumption, and the body weight gains in grams and percentages were analyzed to determine whether such relationship exists between these parameters with the incidence of common spontaneous tumors in Tg.rasH2 mice. None of these body weight parameters had any statistically significant relationship with the incidence of common spontaneous tumors in Tg.rasH2 males, namely lung tumors, splenic hemangiosarcomas, nonsplenic hemangiosarcomas, combined incidence of all hemangiosarcomas, and Harderian gland tumors. These parameters also did not have any statistically significant relationship with the incidence of lung and Harderian gland tumors in females. However, in females, increased initial body weights did have a statistically significant relationship with the nonsplenic hemangiosarcomas, and increased terminal body weights did have a statistically significant relationship with the incidence of splenic hemangiosarcomas, nonsplenic hemangiosarcomas, and the combined incidence of all hemangiosarcomas. In addition, increased body weight gains in grams and percentages had a statistically significant relationship with the combined incidence of all hemangiosarcomas in females, but not separately with splenic and nonsplenic hemangiosarcomas. © 2013 by The Author(s).

  4. 76 FR 3451 - Wage Methodology for the Temporary Non-agricultural Employment H-2B Program

    Science.gov (United States)

    2011-01-19

    ... unemployment rates among specific groups of vulnerable low-wage workers: Youth, Hispanics, and African..., unemployment-related issues, the incorporation or continuation of special procedures in the H-2B program... conditions below the established minimum levels, citing examples of high unemployment rates in industries in...

  5. H2A.Z acidic patch couples chromatin dynamics to regulation of gene expression programs during ESC differentiation.

    Directory of Open Access Journals (Sweden)

    Vidya Subramanian

    Full Text Available The histone H2A variant H2A.Z is essential for embryonic development and for proper control of developmental gene expression programs in embryonic stem cells (ESCs. Divergent regions of amino acid sequence of H2A.Z likely determine its functional specialization compared to core histone H2A. For example, H2A.Z contains three divergent residues in the essential C-terminal acidic patch that reside on the surface of the histone octamer as an uninterrupted acidic patch domain; however, we know little about how these residues contribute to chromatin structure and function. Here, we show that the divergent amino acids Gly92, Asp97, and Ser98 in the H2A.Z C-terminal acidic patch (H2A.Z(AP3 are critical for lineage commitment during ESC differentiation. H2A.Z is enriched at most H3K4me3 promoters in ESCs including poised, bivalent promoters that harbor both activating and repressive marks, H3K4me3 and H3K27me3 respectively. We found that while H2A.Z(AP3 interacted with its deposition complex and displayed a highly similar distribution pattern compared to wild-type H2A.Z, its enrichment levels were reduced at target promoters. Further analysis revealed that H2A.Z(AP3 was less tightly associated with chromatin, suggesting that the mutant is more dynamic. Notably, bivalent genes in H2A.Z(AP3 ESCs displayed significant changes in expression compared to active genes. Moreover, bivalent genes in H2A.Z(AP3 ESCs gained H3.3, a variant associated with higher nucleosome turnover, compared to wild-type H2A.Z. We next performed single cell imaging to measure H2A.Z dynamics. We found that H2A.Z(AP3 displayed higher mobility in chromatin compared to wild-type H2A.Z by fluorescent recovery after photobleaching (FRAP. Moreover, ESCs treated with the transcriptional inhibitor flavopiridol resulted in a decrease in the H2A.Z(AP3 mobile fraction and an increase in its occupancy at target genes indicating that the mutant can be properly incorporated into chromatin

  6. 76 FR 73508 - Wage Methodology for the Temporary Non-Agricultural Employment H-2B Program; Delay of Effective Date

    Science.gov (United States)

    2011-11-29

    ... `` one of the funds made available by this or any other Act for fiscal year 2012 may be used to implement... wage determinations for the H-2B nonimmigrant visa program for employment prior to January 1, 2012, the...

  7. 75 FR 67662 - Wage Methodology for the Temporary Non-Agricultural Employment H-2B Program; Extension of the...

    Science.gov (United States)

    2010-11-03

    ...-Agricultural Employment H- 2B Program; Extension of the Comment Period AGENCIES: Employment and Training Administration. ACTION: Proposed rule; extension of comment period. SUMMARY: On October 5, 2010, the Employment...-agricultural employment and the enforcement of the obligations applicable to employers of such nonimmigrant...

  8. 76 FR 73509 - Wage Methodology for the Temporary Non-Agricultural Employment H-2B Program; Delay of Effective...

    Science.gov (United States)

    2011-11-29

    ... Employment and Training Administration Wage and Hour Division 20 CFR Part 655 RIN 1205-AB61 Wage Methodology... Prevailing Wage Determinations AGENCY: Employment and Training Administration, Wage and Hour Division... effective date of the Wage Methodology for Temporary Non-agricultural Employment H-2B Program Final Rule, 76...

  9. 76 FR 82116 - Wage Methodology for the Temporary Non-Agricultural Employment H-2B Program; Delay of Effective...

    Science.gov (United States)

    2011-12-30

    ... Employment and Training Administration 20 CFR Part 655 RIN 1205-AB61 Wage Methodology for the Temporary Non-Agricultural Employment H- 2B Program; Delay of Effective Date; Impact on Prevailing Wage Determinations AGENCY: Employment and Training Administration, Wage and Hour Division, Labor. ACTION: Guidance. SUMMARY: The...

  10. Regional Traffic Incident Management Programs : implementation guide

    Science.gov (United States)

    2000-11-01

    The purpose of this document is to assist organizations and their leaders in implementing and sustaining regional traffic incident management programs, both by examining some successful models, and by considering some of the lessons learned by early ...

  11. Quantitative image analysis of gamma-H2AX foci induced by ionizing radiation applying open source programs.

    Science.gov (United States)

    González, Jorge Ernesto; Lee, Manual; Barquinero, Joan Francesc; Valente, Marco; Roch-Lefèvre, Sandrine; García, Omar

    2012-04-01

    To test a CellProfiler pipeline for automated counting and characterization of gamma-H2AX foci in color images of human cultured cells. A431 cells were irradiated and stained for gamma-H2AX foci detection. Sets of color images were analyzed visually, and findings were compared with those using FociCounter and CellProfiler software. The CellProfiler pipeline includes some proprieties not present in FociCounter, such as the automatic detection of nuclei, the detection of touching nuclei and the rejection of nuclei that touch the border of the image. The time required for manual operation is associated with the number of images analyzed visually or by FociCounter but not for the CellProfiler program. CellProfiler reduced manual operation time and is about 4 times faster than semiautomatic detection using FociCounter and 10 times faster than visual counting. We conclude that CellProfiler and FociCounter are reliable tools for measuring gamma-H2AX foci. However, CellProfiler overcomes the limitations of the FociCounter program and is able to detect nuclei automatically, saving considerable manual operation.

  12. National Toxic Substance Incidents Program (NTSIP)

    Centers for Disease Control (CDC) Podcasts

    2011-02-03

    This podcast gives an overview of the three components of the National Toxic Substance Incidents Program: state surveillance, national database, and response teams.  Created: 2/3/2011 by Agency for Toxic Substances and Disease Registry.   Date Released: 2/3/2011.

  13. Gamma-H2AX biodosimetry for use in large scale radiation incidents: comparison of a rapid ‘96 well lyse/fix’ protocol with a routine method

    Directory of Open Access Journals (Sweden)

    Jayne Moquet

    2014-03-01

    Full Text Available Following a radiation incident, preliminary dose estimates made by γ-H2AX foci analysis can supplement the early triage of casualties based on clinical symptoms. Sample processing time is important when many individuals need to be rapidly assessed. A protocol was therefore developed for high sample throughput that requires less than 0.1 ml blood, thus potentially enabling finger prick sampling. The technique combines red blood cell lysis and leukocyte fixation in one step on a 96 well plate, in contrast to the routine protocol, where lymphocytes in larger blood volumes are typically separated by Ficoll density gradient centrifugation with subsequent washing and fixation steps. The rapid ‘96 well lyse/fix’ method reduced the estimated sample processing time for 96 samples to about 4 h compared to 15 h using the routine protocol. However, scoring 20 cells in 96 samples prepared by the rapid protocol took longer than for the routine method (3.1 versus 1.5 h at zero dose; 7.0 versus 6.1 h for irradiated samples. Similar foci yields were scored for both protocols and consistent dose estimates were obtained for samples exposed to 0, 0.2, 0.6, 1.1, 1.2, 2.1 and 4.3 Gy of 250 kVp X-rays at 0.5 Gy/min and incubated for 2 h. Linear regression coefficients were 0.87 ± 0.06 (R2 = 97.6% and 0.85 ± 0.05 (R2 = 98.3% for estimated versus actual doses for the routine and lyse/fix method, respectively. The lyse/fix protocol can therefore facilitate high throughput processing for γ-H2AX biodosimetry for use in large scale radiation incidents, at the cost of somewhat longer foci scoring times.

  14. Efficacy of a Community-Based Physical Activity Program KM2H2 for Stroke and Heart Attack Prevention among Senior Hypertensive Patients: A Cluster Randomized Controlled Phase-II Trial.

    Science.gov (United States)

    Gong, Jie; Chen, Xinguang; Li, Sijian

    2015-01-01

    To evaluate the efficacy of the program Keep Moving toward Healthy Heart and Healthy Brain (KM2H2) in encouraging physical activities for the prevention of heart attack and stroke among hypertensive patients enrolled in the Community-Based Hypertension Control Program (CBHCP). Cluster randomized controlled trial with three waves of longitudinal assessments at baseline, 3 and 6 months post intervention. Community-based and patient-centered self-care for behavioral intervention in urban settings of China. A total of 450 participants diagnosed with hypertension from 12 community health centers in Wuhan, China were recruited, and were randomly assigned by center to receive either KM2H2 plus standard CBHCP care (6 centers and 232 patients) or the standard care only (6 centers and 218 patients). KM2H2 is a behavioral intervention guided by the Transtheoretical Model, the Model of Personalized Medicine and Social Capital Theory. It consists of six intervention sessions and two booster sessions engineered in a progressive manner. The purpose is to motivate and maintain physical activities for the prevention of heart attack and stroke. Heart attack and stroke (clinically diagnosed, primary outcome), blood pressure (measured, secondary outcome), and physical activity (self-report, tertiary outcome) were assessed at the individual level during the baseline, 3- and 6-month post-intervention. Relative to the standard care, receiving KM2H2 was associated with significant reductions in the incidence of heart attack (3.60% vs. 7.03%, p heart attack and stroke among senior patients who are on anti-hypertensive medication. Findings of this study provide solid data supporting a formal phase-III trial to establish the effectiveness of KM2H2 for use in community settings for prevention. ISRCTN Register ISRCTN12608966.

  15. Efficacy of a Community-Based Physical Activity Program KM2H2 for Stroke and Heart Attack Prevention among Senior Hypertensive Patients: A Cluster Randomized Controlled Phase-II Trial

    Science.gov (United States)

    Gong, Jie; Chen, Xinguang; Li, Sijian

    2015-01-01

    Objective To evaluate the efficacy of the program Keep Moving toward Healthy Heart and Healthy Brain (KM2H2) in encouraging physical activities for the prevention of heart attack and stroke among hypertensive patients enrolled in the Community-Based Hypertension Control Program (CBHCP). Design Cluster randomized controlled trial with three waves of longitudinal assessments at baseline, 3 and 6 months post intervention. Setting Community-based and patient-centered self-care for behavioral intervention in urban settings of China. Participants A total of 450 participants diagnosed with hypertension from 12 community health centers in Wuhan, China were recruited, and were randomly assigned by center to receive either KM2H2 plus standard CBHCP care (6 centers and 232 patients) or the standard care only (6 centers and 218 patients). Intervention KM2H2 is a behavioral intervention guided by the Transtheoretical Model, the Model of Personalized Medicine and Social Capital Theory. It consists of six intervention sessions and two booster sessions engineered in a progressive manner. The purpose is to motivate and maintain physical activities for the prevention of heart attack and stroke. Outcome Measures Heart attack and stroke (clinically diagnosed, primary outcome), blood pressure (measured, secondary outcome), and physical activity (self-report, tertiary outcome) were assessed at the individual level during the baseline, 3- and 6-month post-intervention. Results Relative to the standard care, receiving KM2H2 was associated with significant reductions in the incidence of heart attack (3.60% vs. 7.03%, p activity at 3- (d = 0.53, 95% CI: 0.21, 0.85) and 6-month (d = 0.45, 95% CI: 0.04, 0.85) post-intervention, respectively. Conclusion The program KM2H2 is efficacious to reduce the risk of heart attack and stroke among senior patients who are on anti-hypertensive medication. Findings of this study provide solid data supporting a formal phase-III trial to establish the

  16. Efficacy of a Community-Based Physical Activity Program KM2H2 for Stroke and Heart Attack Prevention among Senior Hypertensive Patients: A Cluster Randomized Controlled Phase-II Trial.

    Directory of Open Access Journals (Sweden)

    Jie Gong

    Full Text Available To evaluate the efficacy of the program Keep Moving toward Healthy Heart and Healthy Brain (KM2H2 in encouraging physical activities for the prevention of heart attack and stroke among hypertensive patients enrolled in the Community-Based Hypertension Control Program (CBHCP.Cluster randomized controlled trial with three waves of longitudinal assessments at baseline, 3 and 6 months post intervention.Community-based and patient-centered self-care for behavioral intervention in urban settings of China.A total of 450 participants diagnosed with hypertension from 12 community health centers in Wuhan, China were recruited, and were randomly assigned by center to receive either KM2H2 plus standard CBHCP care (6 centers and 232 patients or the standard care only (6 centers and 218 patients.KM2H2 is a behavioral intervention guided by the Transtheoretical Model, the Model of Personalized Medicine and Social Capital Theory. It consists of six intervention sessions and two booster sessions engineered in a progressive manner. The purpose is to motivate and maintain physical activities for the prevention of heart attack and stroke.Heart attack and stroke (clinically diagnosed, primary outcome, blood pressure (measured, secondary outcome, and physical activity (self-report, tertiary outcome were assessed at the individual level during the baseline, 3- and 6-month post-intervention.Relative to the standard care, receiving KM2H2 was associated with significant reductions in the incidence of heart attack (3.60% vs. 7.03%, p < .05 and stroke (5.11% vs. 9.90%, p<0.05, and moderate reduction in blood pressure (-3.72 mmHg in DBP and -2.92 mmHg in DBP at 6-month post-intervention; and significant increases in physical activity at 3- (d = 0.53, 95% CI: 0.21, 0.85 and 6-month (d = 0.45, 95% CI: 0.04, 0.85 post-intervention, respectively.The program KM2H2 is efficacious to reduce the risk of heart attack and stroke among senior patients who are on anti

  17. Metacaspase-8 Modulates Programmed Cell Death Induced by Ultraviolet Light and H2O2 in Arabidopsis

    NARCIS (Netherlands)

    He, R.; Drury, G.E.; Rotari, V.I.; Gordon, A.; Willer, M.; Farzaneh, T.; Woltering, E.J.; Gallois, P.

    2008-01-01

    Programmed cell death (PCD) is a genetically controlled cell death that is regulated during development and activated in response to environmental stresses or pathogen infection. The degree of conservation of PCD across kingdoms and phylum is not yet clear; however, whereas caspases are proteases

  18. Cobalt alleviates GA-induced programmed cell death in wheat aleurone layers via the regulation of H2O2 production and heme oxygenase-1 expression.

    Science.gov (United States)

    Wu, Mingzhu; Li, Jiale; Wang, Fangquan; Li, Feng; Yang, Jun; Shen, Wenbiao

    2014-11-14

    Heme oxygenase-1 (HO-1) and hydrogen peroxide (H2O2) are key signaling molecules that are produced in response to various environmental stimuli. Here, we demonstrate that cobalt is able to delay gibberellic acid (GA)-induced programmed cell death (PCD) in wheat aleurone layers. A similar response was observed when samples were pretreated with carbon monoxide (CO) or bilirubin (BR), two end-products of HO catalysis. We further observed that increased HO-1 expression played a role in the cobalt-induced alleviation of PCD. The application of HO-1-specific inhibitor, zinc protoporphyrin-IX (ZnPPIX), substantially prevented the increases of HO-1 activity and the alleviation of PCD triggered by cobalt. The stimulation of HO-1 expression, and alleviation of PCD might be caused by the initial H2O2 production induced by cobalt. qRT-PCR and enzymatic assays revealed that cobalt-induced gene expression and the corresponding activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX), three enzymes that metabolize reactive oxygen species, were consistent with the H2O2 accumulation during GA treatment. These cobalt responses were differentially blocked by co-treatment with ZnPPIX. We therefore suggest that HO-1 functions in the cobalt-triggered alleviation of PCD in wheat aleurone layers, which is also dependent on the enhancement of the activities of antioxidant enzymes.

  19. H2 Reconstitution

    National Research Council Canada - National Science Library

    Skipper, Mike

    2002-01-01

    .... The H2 source is an existing wideband source that was developed at the AFRL. A recent AFRL requirement for a wideband impulse generator to use in materials tests has provided the need to update the H2 source for the current test requirements...

  20. Reduced Cardiovascular Disease Incidence With a National Lifestyle Change Program.

    Science.gov (United States)

    Jackson, Sandra L; Safo, Sandra; Staimez, Lisa R; Long, Qi; Rhee, Mary K; Cunningham, Solveig A; Olson, Darin E; Tomolo, Anne M; Ramakrishnan, Usha; Narayan, K M Venkat; Phillips, Lawrence S

    2017-04-01

    Lifestyle change programs implemented within healthcare systems could reach many Americans, but their impact on cardiovascular disease (CVD) remains unclear. The MOVE! program is the largest lifestyle change program implemented in a healthcare setting in the U.S. This study aimed to determine whether MOVE! participation was associated with reduced CVD incidence. This retrospective cohort study, analyzed in 2013-2015, used national Veterans Health Administration databases to identify MOVE! participants and eligible non-participants for comparison (2005-2012). Patients eligible for MOVE!-obese or overweight with a weight-related health condition, and no baseline CVD-were examined (N=1,463,003). Of these, 169,248 (12%) were MOVE! Patients were 92% male, 76% white, with mean age 52 years and BMI of 32. The main outcome was incidence of CVD (ICD-9 and procedure codes for coronary artery disease, cerebrovascular disease, peripheral vascular disease, and heart failure). Adjusting for age, race, sex, BMI, statin use, and baseline comorbidities, over a mean 4.9 years of follow-up, MOVE! participation was associated with lower incidence of total CVD (hazard ratio [HR]=0.83, 95% CI=0.80, 0.86); coronary artery disease (HR=0.81, 95% CI=0.77, 0.86); cerebrovascular disease (HR=0.87, 95% CI=0.82, 0.92); peripheral vascular disease (HR=0.89, 95% CI=0.83, 0.94); and heart failure (HR=0.78, 95% CI=0.74, 0.83). The association between MOVE! participation and CVD incidence remained significant when examined across categories of race/ethnicity, BMI, diabetes, hypertension, smoking status, and statin use. Although participation was limited, MOVE! was associated with reduced CVD incidence in a nationwide healthcare setting. Published by Elsevier Inc.

  1. H2@Scale Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ruth, Mark

    2017-07-12

    'H2@Scale' is a concept based on the opportunity for hydrogen to act as an intermediate between energy sources and uses. Hydrogen has the potential to be used like the primary intermediate in use today, electricity, because it too is fungible. This presentation summarizes the H2@Scale analysis efforts performed during the first third of 2017. Results of technical potential uses and supply options are summarized and show that the technical potential demand for hydrogen is 60 million metric tons per year and that the U.S. has sufficient domestic resources to meet that demand. A high level infrastructure analysis is also presented that shows an 85% increase in energy on the grid if all hydrogen is produced from grid electricity. However, a preliminary spatial assessment shows that supply is sufficient in most counties across the U.S. The presentation also shows plans for analysis of the economic potential for the H2@Scale concept. Those plans involve developing supply and demand curves for potential hydrogen generation options and as compared to other options for use of that hydrogen.

  2. H2 Reconstitution

    Science.gov (United States)

    2002-02-01

    AFRL-DE-TR-2002-1033 AFRL-DE-TR- 2002-1033 H2 RECONSTITUTION Mike Skipper et al. ASR Corporation 7817 Bursera NW Albuquerque, NM 87120 February 2002...PERFORMING ORGANIZATION REPORT NUMBER ASR Corporation 7817 Bursera NW Albuquerque, NM 87120 DC-TR-0328.008-1 9. SPONSORING / MONITORING AGENCY NAME...Albuquerque, NM 87110 1 cy ASR Corporation 7817 Bursera NW Albuquerque, NM 87120 1 cy Jeff Berger AFRL/DEHP Kirtland AFB, NM 87117 1 cy Tyrone Tran AFRL/DEHP Kirtland AFB, NM 87117 1 cy 40

  3. Moderate Temperature Dense Phase Hydrogen Storage Materials within the US Department of Energy (DOE H2 Storage Program: Trends toward Future Development

    Directory of Open Access Journals (Sweden)

    Scott McWhorter

    2012-05-01

    Full Text Available Hydrogen has many positive attributes that make it a viable choice to augment the current portfolio of combustion-based fuels, especially when considering reducing pollution and greenhouse gas (GHG emissions. However, conventional methods of storing H2 via high-pressure or liquid H2 do not provide long-term economic solutions for many applications, especially emerging applications such as man-portable or stationary power. Hydrogen storage in materials has the potential to meet the performance and cost demands, however, further developments are needed to address the thermodynamics and kinetics of H2 uptake and release. Therefore, the US Department of Energy (DOE initiated three Centers of Excellence focused on developing H2 storage materials that could meet the stringent performance requirements for on-board vehicular applications. In this review, we have summarized the developments that occurred as a result of the efforts of the Metal Hydride and Chemical Hydrogen Storage Centers of Excellence on materials that bind hydrogen through ionic and covalent linkages and thus could provide moderate temperature, dense phase H2 storage options for a wide range of emerging Proton Exchange Membrane Fuel Cell (PEM FC applications.

  4. On the Emission of Electrons from Solid H_2 and D_2 by Bombardment with 1-3 keV Electrons up to Very Large Angles of Incidence

    DEFF Research Database (Denmark)

    Schou, Jørgen; Sørensen, H.

    1982-01-01

    -65°. Only at large angles and low energies were the results different for H2 and D2, those for H2 being the lower ones. The angular variation of the SEE coefficient δ may be written as δ(θ)=δ(0)(cos θ)3/2 up to an angle of 65-75°. For H2 the SEE coefficient is around 0.65 times that the D2 except......, an ionization cascade treatment leads to an expression for the behavior of the yield of those secondary electrons that are generated directly by the primaries. The agreement with experimental data is good...

  5. Electron mass stopping power in H2

    Science.gov (United States)

    Fursa, Dmitry V.; Zammit, Mark C.; Threlfall, Robert L.; Savage, Jeremy S.; Bray, Igor

    2017-08-01

    Calculations of electron mass stopping power (SP) of electrons in H2 have been performed using the convergent close-coupling method for incident electron energies up to 2000 eV. Convergence of the calculated SP has been established by increasing the size of the close-coupling expansion from 9 to 491 states. Good agreement was found with the SP measurements of Munoz et al. [Chem. Phys. Lett. 433, 253 (2007), 10.1016/j.cplett.2006.10.114].

  6. Collisional Quenching of Highly-Excited H2 due to H2 Collisions

    Science.gov (United States)

    Wan, Yier; Yang, Benhui H.; Stancil, Phillip C.; Naduvalath, Balakrishnan; Forrey, Robert C.; This work was partially support by Hubble grant HST-AT-13899. We thank Kyle Walkerassistance with vrrmm.

    2017-06-01

    Collision-induced energy transfer involving H2 molecules are of significant interest, since H2 is the most abundant molecular species in the universe. Collisional de-excitation rate coefficients of the H2-H2 system are necessary to produce accurate models of astrophysical environments. However, accurate calculations of collisional energy transfer are still a challenging problem, especially for highly-excited H2 because a large number of levels must be included in the calculation.Currently, most data are limited to initial rotational levels j up to 8 or initial vibrational levels up to 3. The vast majority of these results involve some form of a reduced-dimensional approach which may be of questionable accuracy. A reliable and accurate four-dimensional PES computed by Patkowski et al. is used in this work along with two quantum scattering programs (MOLSCAT and vrrmm). Another accurate full-dimensional PES has been reported for the H2-H2 system by Hinde.Not all transitions will be explicitly calculated. A zero-energy scaling technique (ZEST) is used to estimate some intermediate transitions from calculated rate coefficients. New inelastic quenching cross section for para-H2+para-H2 collisions with initial level j= 10, 12, 14, 18, 24 are calculated. Calculations for other de-excitation transitions from higher initial levels and collisions involving other spin isomer of hydrogen, ortho-H2+para-H2, ortho-H2+ortho-H2 and para-H2+ortho-H2 are in progress. The coupled- states approximation is also applied to obtain cross sections at high energy.K. Patkowski, et al., J. Chem. Phys. 129, 094304 (2008).J. M. Hutson and S. Green, MOLSCAT Computer code, v14 (1994).K. Walker, 2013, VRRMM: Vibrational/Rotational Rich Man’s MOLSCAT v3.1.K. Walker, Song, L., Yang, B. H.,et al. 2015, ApJ, \\811,27.S. Green, J. Chem. Phys. 62, 2271 (1975).Flower, D. R., Roueff, E. 1998, J. Phys. B, 31, 2935.T. -G. Lee, N. Balakrishnan, R. C. Forrey, P. C. Stancil, G. Shaw, D. R. Schultz, and G. J

  7. H2@Scale Workshop Report

    Energy Technology Data Exchange (ETDEWEB)

    Pivovar, Bryan

    2017-03-31

    Final report from the H2@Scale Workshop held November 16-17, 2016, at the National Renewable Energy Laboratory in Golden, Colorado. The U.S. Department of Energy's National Renewable Energy Laboratory hosted a technology workshop to identify the current barriers and research needs of the H2@Scale concept. H2@Scale is a concept regarding the potential for wide-scale impact of hydrogen produced from diverse domestic resources to enhance U.S. energy security and enable growth of innovative technologies and domestic industries. Feedback received from a diverse set of stakeholders at the workshop will guide the development of an H2@Scale roadmap for research, development, and early stage demonstration activities that can enable hydrogen as an energy carrier at a national scale.

  8. School Nutrition Programs and the Incidence of Childhood Obesity

    Science.gov (United States)

    Millimet, Daniel L.; Tchernis, Rusty; Husain, Muna

    2010-01-01

    Given the recent rise in childhood obesity, the School Breakfast Program (SBP) and National School Lunch Program (NSLP) have received renewed attention. Using panel data on more than 13,500 primary school students, we assess the relationship between SBP and NSLP participation and (relatively) long-run measures of child weight. After documenting a…

  9. 78 FR 4154 - Identification of Foreign Countries Whose Nationals Are Eligible To Participate in the H-2A and H...

    Science.gov (United States)

    2013-01-18

    ... the H-2A and H-2B Nonimmigrant Worker Programs AGENCY: Office of the Secretary, DHS. ACTION: Notice... Services (USCIS) may approve petitions for H-2A and H-2B nonimmigrant status only for nationals of... identifying 59 countries whose nationals are eligible to participate in the H-2A and H-2B programs for the...

  10. Extracting classification rules from an informatic security incidents repository by genetic programming

    Directory of Open Access Journals (Sweden)

    Carlos Javier Carvajal Montealegre

    2015-04-01

    Full Text Available This paper describes the data mining process to obtain classification rules over an information security incident data collection, explaining in detail the use of genetic programming as a mean to model the incidents behavior and representing such rules as decision trees. The described mining process includes several tasks, such as the GP (Genetic Programming approach evaluation, the individual's representation and the algorithm parameters tuning to upgrade the performance. The paper concludes with the result analysis and the description of the rules obtained, suggesting measures to avoid the occurrence of new informatics attacks. This paper is a part of the thesis work degree: Information Security Incident Analytics by Data Mining for Behavioral Modeling and Pattern Recognition (Carvajal, 2012.

  11. Why We Complete a Teacher Education Program: Credentialed Teachers, a Critical Incident Inquiry

    Science.gov (United States)

    Alastuey, Lisa; Justice, Madeline; Weeks, Sandy; Hardy, James

    2005-01-01

    This study focused on the initial reasons individuals enter and complete the teacher education program, and pass the state test. These same individuals do not enter the public school classroom. This study identified meaningful categories for incidents reported as effective or helpful to successfully facilitating their decision to enter and…

  12. Cancer Incidence in Egypt: Results of the National Population-Based Cancer Registry Program

    Directory of Open Access Journals (Sweden)

    Amal S. Ibrahim

    2014-01-01

    Full Text Available Background. This paper aims to present cancer incidence rates at national and regional level of Egypt, based upon results of National Cancer Registry Program (NCRP. Methods. NCRP stratified Egypt into 3 geographical strata: lower, middle, and upper. One governorate represented each region. Abstractors collected data from medical records of cancer centers, national tertiary care institutions, Health Insurance Organization, Government-Subsidized Treatment Program, and death records. Data entry was online. Incidence rates were calculated at a regional and a national level. Future projection up to 2050 was also calculated. Results. Age-standardized incidence rates per 100,000 were 166.6 (both sexes, 175.9 (males, and 157.0 (females. Commonest sites were liver (23.8%, breast (15.4%, and bladder (6.9% (both sexes: liver (33.6% and bladder (10.7% among men, and breast (32.0% and liver (13.5% among women. By 2050, a 3-fold increase in incident cancer relative to 2013 was estimated. Conclusion. These data are the only available cancer rates at national and regional levels of Egypt. The pattern of cancer indicated the increased burden of liver cancer. Breast cancer occupied the second rank. Study of rates of individual sites of cancer might help in giving clues for preventive programs.

  13. [Breast cancer incidence related with a population-based screening program].

    Science.gov (United States)

    Natal, Carmen; Caicoya, Martín; Prieto, Miguel; Tardón, Adonina

    2015-02-20

    To compare breast cancer cumulative incidence, time evolution and stage at diagnosis between participants and non-participant women in a population-based screening program. Cohort study of breast cancer incidence in relation to participation in a population screening program. The study population included women from the target population of the screening program. The source of information for diagnostics and stages was the population-based cancer registry. The analysis period was 1999-2010. The Relative Risk for invasive, in situ, and total cancers diagnosed in participant women compared with non-participants were respectively 1.16 (0.94-1.43), 2.98 (1.16-7.62) and 1.22 (0.99-1.49). The Relative Risk for participants versus non-participants was 2.47 (1.55-3.96) for diagnosis at stagei, 2.58 (1.67-3.99) for T1 and 2.11 (1.38-3.23) for negative lymph node involvement. The cumulative incidence trend had two joint points in both arms, with an Annual Percent of Change of 92.3 (81.6-103.5) between 1999-2001, 18.2 (16.1-20.3) between 2001-2005 and 5.9 (4.0-7.8) for the last period in participants arm, and 72.6 (58.5-87.9) between 1999-2001, 12.6 (7.9-17.4) between 2001-2005, and 8.6 (6.5-10.6) in the last period in the non-participant arm. Participating in the breast cancer screening program analyzed increased the in situ cumulative cancer incidence, but not the invasive and total incidence. Diagnoses were earlier in the participant arm. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

  14. Intraoperative waste in spine surgery: incidence, cost, and effectiveness of an educational program.

    Science.gov (United States)

    Soroceanu, Alex; Canacari, Elena; Brown, Eric; Robinson, Adam; McGuire, Kevin J

    2011-09-01

    Prospective observational study. This study aims to quantify the incidence of intraoperative waste in spine surgery and to examine the efficacy of an educational program directed at surgeons to induce a reduction in the intraoperative waste. Spine procedures are associated with high costs. Implants are a main contributor of these costs. Intraoperative waste further exacerbates the high cost of surgery. Data were collected during a 25-month period from one academic medical center (15-month observational period, 10-month post-awareness program). The total number of spine procedures and the incidence of intraoperative waste were recorded prospectively. Other variables recorded included the type of product wasted, cost associated with the product or implant wasted, and reason for the waste. Intraoperative waste occurred in 20.2% of the procedures prior to the educational program and in 10.3% of the procedures after the implementation of the program (P spine budget. After the awareness program this proportion decrease to an average of 1.2% (P = 0.003). Intraoperative waste in spine surgery exacerbates the already costly procedures. Extrapolation of this data to the national level leads to an annual estimate of $126,722,000 attributable to intraoperative spine waste. A simple educational program proved to be and continues to be effective in making surgeons aware of the import of their choices and the costs related to surgical waste.

  15. The Icelandic and Nordic cervical screening programs: trends in incidence and mortality rates through 1995.

    Science.gov (United States)

    Sigurdsson, K

    1999-07-01

    The objective of cervical cancer screening is to lower the incidence and mortality rates of the disease. This study evaluates the effectiveness of cervical screening and the UICC and EC screening recommendations based on the Nordic screening experience. The study analyzes the features of the Icelandic and the Nordic screening programs and the observed trends in the incidence and mortality rates in these countries through 1995. Organized screening started in all the Nordic countries soon after 1960 and had nation-wide coverage in all these countries, except in Denmark (45% coverage in 1991), by around 1973 but in Norway screening was only spontaneous up to late in 1994. Up to 1985 the target age group and screening interval were most intensive in Iceland, followed by Finland, Sweden and Denmark. All countries except Finland lowered the lower age limit and intensified the screening intervals after 1985. Through the period 1986-1995 the reduction in both the mortality and the incidence rates was greatest in Iceland (mortality: 76% and incidence: 67%) and Finland (73% and 75%, respectively), intermediate in Sweden (60% and 55%, respectively) and Denmark (55% and 54%, respectively), and lowest in Norway (43% and 34%, respectively). The age-specific incidence in the 20-29 age group has been increasing since 1971 in all the Nordic countries, except in Finland, where the yearly registered age-specific incidence has been increasing in the targeted 30-54 age group since 1991. In Iceland screening has greatly affected the rate of all stages of squamous cell carcinoma, but not the rate of adeno- and adenosquamous carcinomas. In fact the rate of adenocarcinoma has been increasing. Organized screening is more effective than spontaneous screening in reducing the risk of cervical cancer. Although differences in environmental, biological and ethnic factors may call for different screening strategies, screening should preferably start soon after age 20 with a screening interval of 2

  16. 77 FR 65715 - Agency Information Collection Activities; Submissions for OMB Review; Comment Request; H-2A...

    Science.gov (United States)

    2012-10-30

    ... Foreign Workers, H-2B Foreign Labor Certification Program; and Application for Prevailing Wage... Certification Letter for H-2A Agricultural Foreign Workers, H-2B Foreign Labor Certification Program, and... Secretary of Labor to certify, among other things, that any foreign worker seeking to enter the United...

  17. Effect of hepatitis A vaccination programs for migrant children on the incidence of hepatitis A in The Netherlands.

    Science.gov (United States)

    Suijkerbuijk, Anita W M; Lindeboom, Robert; van Steenbergen, Jim E; Sonder, Gerard J B; Doorduyn, Yvonne

    2009-06-01

    Since 1998 Municipal Public Health Services (MPHSs) in The Netherlands carried out Hepatitis A (HAV) vaccination programs for Turkish and Moroccan children to reduce import and secondary HAV infections. The aim of this study was to assess the effects of the programs on HAV incidence. MPHSs were questioned about HAV vaccination programs for migrant children. Notification data of HAV over the period 1995-2006 were analysed. Since 1998, 19 MPHSs (58%) organized vaccination programs for Turkish and Moroccan children. A large variation in the range of activities in HAV vaccination programs was observed. In The Netherlands, HAV incidence declined, from 6.5 per 100,000 inhabitants in 1995 to 1.3 in 2005. HAV incidence in children of Turkish and Moroccan decent declined from 70.3 per 100,000 in 2000 to 13.5 per 100,000 in 2005. Regions where MPHSs organized vaccination campaigns had the steepest decline in HAV incidence. The decline in HAV incidence in The Netherlands coincided with that observed for the rest of Europe. Therefore, also other causes than the enhanced vaccination programs could have contributed to this effect. At present, low priority is placed on continuing these HAV vaccination programs, as in areas without enhanced programs the incidence also declined to very low levels. Because HAV is still endemic in Morocco and Turkey, it remains important that all travellers to these countries are vaccinated against HAV, regardless of their country of origin.

  18. North Carolina Toxic Substance Incidents Program 2010-2015: Identifying Areas for Injury Prevention Efforts.

    Science.gov (United States)

    Eiffert, Samantha; Etienne, Suze; Hirsch, Annie; Langley, Ricky

    2017-08-06

    The National Toxic Substance Incidents Program (NTSIP) is a surveillance system designed to capture acute toxic substance releases, factors contributing to the release, and any associated injuries. North Carolina has participated since 2010, when NTSIP was established. This article will present a descriptive statistical summary from 2010 to 2015 focused on releases that resulted in injuries in order to identify areas for public health prevention efforts. Of the 1690 toxic releases in North Carolina, 155 incidents resulted in injuries and 500 people were injured. Carbon monoxide injured the greatest number of people. Of the incidents that resulted in injuries, 68 occurred at private vehicles or residences (44%), injuring 124 people (25%). Over half of events where at least one responder was injured occurred at private vehicles or residences. Events occurring at private residences did not have a significant relationship between evacuations and injuries, while for industry-related events, the odds of an evacuation being ordered were 8.18 times greater (OR = 8.18, 95% CI = 5.19, 12.89) when there were injuries associated with an event. Intervention efforts should focus on preventing responder injuries while responding to private residence releases and educating the general public on how to prevent injuries by self-evacuating areas where hazardous chemicals have been released.

  19. North Carolina Toxic Substance Incidents Program 2010–2015: Identifying Areas for Injury Prevention Efforts

    Science.gov (United States)

    Eiffert, Samantha; Etienne, Suze; Hirsch, Annie

    2017-01-01

    The National Toxic Substance Incidents Program (NTSIP) is a surveillance system designed to capture acute toxic substance releases, factors contributing to the release, and any associated injuries. North Carolina has participated since 2010, when NTSIP was established. This article will present a descriptive statistical summary from 2010 to 2015 focused on releases that resulted in injuries in order to identify areas for public health prevention efforts. Of the 1690 toxic releases in North Carolina, 155 incidents resulted in injuries and 500 people were injured. Carbon monoxide injured the greatest number of people. Of the incidents that resulted in injuries, 68 occurred at private vehicles or residences (44%), injuring 124 people (25%). Over half of events where at least one responder was injured occurred at private vehicles or residences. Events occurring at private residences did not have a significant relationship between evacuations and injuries, while for industry-related events, the odds of an evacuation being ordered were 8.18 times greater (OR = 8.18, 95% CI = 5.19, 12.89) when there were injuries associated with an event. Intervention efforts should focus on preventing responder injuries while responding to private residence releases and educating the general public on how to prevent injuries by self-evacuating areas where hazardous chemicals have been released. PMID:29051448

  20. Photolysis of H2O-H2O2 Mixtures: The Destruction of H2O2

    Science.gov (United States)

    Loeffler, M. J.; Fama, M.; Baragiola, R. A.; Carlson, R. W.

    2013-01-01

    We present laboratory results on the loss of H2O2 in solid H2O + H2O2 mixtures at temperatures between 21 and 145 K initiated by UV photolysis (193 nm). Using infrared spectroscopy and microbalance gravimetry, we measured the decrease of the 3.5 micrometer infrared absorption band during UV irradiation and obtained a photodestruction cross section that varies with temperature, being lowest at 70 K. We use our results, along with our previously measured H2O2 production rates via ionizing radiation and ion energy fluxes from the spacecraft to compare H2O2 creation and destruction at icy satellites by ions from their planetary magnetosphere and from solar UV photons. We conclude that, in many cases, H2O2 is not observed on icy satellite surfaces because the H2O2 photodestruction rate is much higher than the production rate via energetic particles, effectively keeping the H2O2 infrared signature at or below the noise level.

  1. H2A and H2B tails are essential to properly reconstitute nucleosome core particles.

    Science.gov (United States)

    Bertin, Aurélie; Durand, Dominique; Renouard, Madalena; Livolant, Françoise; Mangenot, Stéphanie

    2007-11-01

    The conformation of recombinant Nucleosome Core Particles (NCPs) lacking H2A and H2B histone tails (gH2AgH2B) are studied. The migration of these particles in acrylamide native gels is slowed down compared to intact reconstituted NCPs. gH2AgH2B NCPs are also much more sensitive to nuclease digestion than intact NCPs. Small angle X-ray scattering (SAXS) experiments point out that the absence of H2A and H2B tails produces small but significant conformational changes of the octamers conformation (without wrapped DNA), whereas gH2AgH2B NCP conformations are significantly altered. A separation of about 25-30 bp from the core could account for the experimental curves, but other types of DNA superhelix deformation cannot be excluded. The distorted gH2AgH2B octamer may not allow the correct winding of DNA around the core. The absence of the H2A and H2B tails would further prevent the secondary sliding of the DNA around the core and therefore impedes the stabilisation of the particle. Cryo-electron microscopy on the same particles also shows a detachment of DNA portions from the particle core. The effect is even stronger because the vitrification of the samples worsens the instability of gH2AgH2B NCPs.

  2. H2O2: A Dynamic Neuromodulator

    Science.gov (United States)

    Rice, Margaret E.

    2012-01-01

    Increasing evidence implicates hydrogen peroxide (H2O2) as an intra- and intercellular signaling molecule that can influence processes from embryonic development to cell death. Most research has focused on relatively slow signaling, on the order of minutes to days, via second messenger cascades. However, H2O2 can also mediate subsecond signaling via ion channel activation. This rapid signaling has been examined most thoroughly in the nigrostriatal dopamine (DA) pathway, which plays a key role in facilitating movement mediated by the basal ganglia. In DA neurons of the substantia nigra, endogenously generated H2O2 activates ATP-sensitive K+ (KATP) channels that inhibit DA neuron firing. In the striatum, H2O2 generated downstream from glutamatergic AMPA receptor activation in medium spiny neurons acts as a diffusible messenger that inhibits axonal DA release, also via KATP channels. The source of dynamically generated H2O2 is mitochondrial respiration; thus, H2O2 provides a novel link between activity and metabolism via KATP channels. Additional targets of H2O2 include transient receptor potential (TRP) channels. In contrast to the inhibitory effect of H2O2 acting via KATP channels, TRP channel activation is excitatory. This review describes emerging roles of H2O2 as a signaling agent in the nigrostriatal pathway and other basal ganglia neurons. PMID:21666063

  3. Double strand break repair functions of histone H2AX

    Energy Technology Data Exchange (ETDEWEB)

    Scully, Ralph, E-mail: rscully@bidmc.harvard.edu; Xie, Anyong

    2013-10-15

    Chromosomal double strand breaks provoke an extensive reaction in neighboring chromatin, characterized by phosphorylation of histone H2AX on serine 139 of its C-terminal tail (to form “γH2AX”). The γH2AX response contributes to the repair of double strand breaks encountered in a variety of different contexts, including those induced by ionizing radiation, physiologically programmed breaks that characterize normal immune cell development and the pathological exposure of DNA ends triggered by telomere dysfunction. γH2AX also participates in the evolutionarily conserved process of sister chromatid recombination, a homologous recombination pathway involved in the suppression of genomic instability during DNA replication and directly implicated in tumor suppression. At a biochemical level, the γH2AX response provides a compelling example of how the “histone code” is adapted to the regulation of double strand break repair. Here, we review progress in research aimed at understanding how γH2AX contributes to double strand break repair in mammalian cells.

  4. H2S Hazard on ODP Leg 146

    Science.gov (United States)

    Francis, T. J. G.; Olivas, R. E.

    On the Ocean Drilling Program's Leg 146, extremely high concentrations of hydrogen sulfide (H2S) were encountered in cores acquired from the top 17 m of the sedimentary section at Site 892, in 674-m water depth off the coast of Oregon. The amount of H2S given off by these cores on the deck of the drill ship was sufficient to create a safety hazard and, if improperly handled, could have administered a lethal dose. The purpose of this article is to warn the scientific community of the dangers of handling this naturally occurring material.The cores were several orders of magnitude richer in H2S than any previously recovered by DSDP/ODP in 25 years of scientific ocean drilling. Gas hydrates were recovered from the same interval, and it is possible that the H2S may have been stored in a hydrate structure. The cores were split and allowed to degas in the open air before being taken into the ship's laboratory. ODP technical staff handling the cores wore breathing apparatus and used hand-held H2S detector instruments. Key personnel on the drill ship are regularly trained in the hazards of H2S, which is commonly encountered in oil and gas drilling.

  5. Effect of hepatitis A vaccination programs for migrant children on the incidence of hepatitis A in The Netherlands

    NARCIS (Netherlands)

    Suijkerbuijk, Anita W. M.; Lindeboom, Robert; van Steenbergen, Jim E.; Sonder, Gerard J. B.; Doorduyn, Yvonne

    2009-01-01

    Since 1998 Municipal Public Health Services (MPHSs) in The Netherlands carried out Hepatitis A (HAV) vaccination programs for Turkish and Moroccan children to reduce import and secondary HAV infections. The aim of this study was to assess the effects of the programs on HAV incidence. MPHSs were

  6. Intervening at the Setting Level to Prevent Behavioral Incidents in Residential Child Care: Efficacy of the CARE Program Model.

    Science.gov (United States)

    Izzo, Charles V; Smith, Elliott G; Holden, Martha J; Norton, Catherine I; Nunno, Michael A; Sellers, Deborah E

    2016-07-01

    The current study examined the impact of a setting-level intervention on the prevention of aggressive or dangerous behavioral incidents involving youth living in group care environments. Eleven group care agencies implemented Children and Residential Experiences (CARE), a principle-based program that helps agencies use a set of evidence-informed principles to guide programming and enrich the relational dynamics throughout the agency. All agencies served mostly youth referred from child welfare. The 3-year implementation of CARE involved intensive agency-wide training and on-site consultation to agency leaders and managers around supporting and facilitating day-to-day application of the principles in both childcare and staff management arenas. Agencies provided data over 48 months on the monthly frequency of behavioral incidents most related to program objectives. Using multiple baseline interrupted time series analysis to assess program effects, we tested whether trends during the program implementation period declined significantly compared to the 12 months before implementation. Results showed significant program effects on incidents involving youth aggression toward adult staff, property destruction, and running away. Effects on aggression toward peers and self-harm were also found but were less consistent. Staff ratings of positive organizational social context (OSC) predicted fewer incidents, but there was no clear relationship between OSC and observed program effects. Findings support the potential efficacy of the CARE model and illustrate that intervening "upstream" at the setting level may help to prevent coercive caregiving patterns and increase opportunities for healthy social interactions.

  7. Oxygen sensitivity of algal H2- production.

    Science.gov (United States)

    Ghirardi, M L; Togasaki, R K; Seibert, M

    1997-01-01

    Photoproduction of H2 by green algae utilizes electrons originating from the photosynthetic oxidation of water and does not require metabolic intermediates. However, algal hydrogenases are extremely sensitive to O(2), which limits their usefulness in future commercial H2-production systems. We designed an experimental technique for the selection of O2-tolerant, H2-producing variants of Chlamydomonas reinhardtii based on the ability of wild-type cells to survive a short (20 min) exposure to metronidazole in the presence of controlled concentrations of O2. The number of survivors depends on the metronidazole concentration, light intensity, preinduction of the hydrogenase, and the presence or absence of O2. Finally, we demonstrate that some of the selected survivors in fact exhibit H2-production capacity that is less sensitive to O2 than the original wild-type population.

  8. Interval breast cancers: Absolute and proportional incidence and blinded review in a community mammographic screening program

    Energy Technology Data Exchange (ETDEWEB)

    Carbonaro, Luca A., E-mail: luca.carbonaro@gmail.com [Unità di Radiologia, IRCCS Policlinico San Donato, Piazza E. Malan 2, San Donato Milanese (Mi) 20097 (Italy); Azzarone, Antonio [Servizio di Radiologia, Azienda Ospedaliera Circolo di Melegnano, Via Pandina 1, Vizzolo Predabissi (Mi) 20070 (Italy); Paskeh, Bijan Babaei [Unità di Radiologia, IRCCS Policlinico San Donato, Piazza E. Malan 2, San Donato Milanese (Mi) 20097 (Italy); Brambilla, Giorgio [Dipartimento di Radiologia, IRCCS Istituto Clinico Humanitas, Via Manzoni 56, Rozzano (Mi) 20089 (Italy); Brunelli, Silvia [Centro di Prevenzione Senologica, ULSS 20, Piazza Lambranzi, Verona 37034 (Italy); Calori, Anna [Servizio di Radiologia, Azienda Ospedaliera Circolo di Melegnano, Via Pandina 1, Vizzolo Predabissi (Mi) 20070 (Italy); Caumo, Francesca [Centro di Prevenzione Senologica, ULSS 20, Piazza Lambranzi, Verona 37034 (Italy); Malerba, Paolo [Dipartimento di Radiologia, IRCCS Istituto Clinico Humanitas, Via Manzoni 56, Rozzano (Mi) 20089 (Italy); Menicagli, Laura [Unità di Radiologia, IRCCS Policlinico San Donato, Piazza E. Malan 2, San Donato Milanese (Mi) 20097 (Italy); Sconfienza, Luca M. [Unità di Radiologia, IRCCS Policlinico San Donato, Piazza E. Malan 2, San Donato Milanese (Mi) 20097 (Italy); Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, Milano (Italy); Vadalà, Giuseppe [Servizio di Radiologia, Azienda Ospedaliera Circolo di Melegnano, Via Pandina 1, Vizzolo Predabissi (Mi) 20070 (Italy); Brambilla, Gelma; Fantini, Luigi [Servizio di Medicina Preventiva delle Comunità, ASL Milano 2, Via Friuli 2, Lacchiarella (Mi) 20084 (Italy); Ciatto, Stefano [Screening Program, ULSS 16, Padova (Italy); and others

    2014-02-15

    Purpose: To evaluate the performance of the first years since the beginning of a mammographic population-based screening program. Materials and methods: Women aged 49–69 were invited biennially for two-view film-screen mammography and double reading without arbitration was performed. Interval cancers (ICs) from 2001 to 2006 were identified using screening archives, local pathology archives, and hospital discharge records. The proportional incidence of IC was determined considering breast cancers expected without screening. Three offsite radiologists experienced in breast cancer screening blindly evaluated mammograms prior to diagnosis, randomly mixed with negative mammograms (1:2 ratio). Cases unrecalled at review were considered as true ICs, those recalled by only one reviewer as minimal signs, and those recalled by two or three reviewers as missed cancers. T and N stage of the reviewed ICs were evaluated and compared. Results: A total of 86,276 first level mammograms were performed. Mean recall rate was 6.8% at first and 4.6% at repeat screening. We had 476 screen-detected cancers and 145 ICs (10 of them ductal carcinomas in situ). Absolute incidence was 17 per 10,000 screening examinations. Invasive proportional incidence was 19% (44/234) in the first year, 39% (91/234) in the second year, and 29% (135/468) in the two-year interval. Of 145 ICs, 130 (90%) were reviewed mixed with 287 negative controls: 55% (71/130) resulted to be true ICs, 24% (31/130) minimal signs, and 22% (28/130) missed cancers. The rate of ICs diagnosed in the first year interval was 21% (15/71) for true ICs, 46% (13/28) for missed cancers, and 39% (12/31) for minimal signs, with a significant difference of true ICs rate compared to missed cancers rate (p = 0.012). A higher rate of T3 and T4 stages was found for missed cancers (18%, 5/28) compared to minimal signs (6%, 2/31) or true ICs (8%, 6/71), while the rate of N2 and N3 stage for both minimal signs (19%, 6/31) or missed cancers (25

  9. Interval breast cancers: absolute and proportional incidence and blinded review in a community mammographic screening program.

    Science.gov (United States)

    Carbonaro, Luca A; Azzarone, Antonio; Paskeh, Bijan Babaei; Brambilla, Giorgio; Brunelli, Silvia; Calori, Anna; Caumo, Francesca; Malerba, Paolo; Menicagli, Laura; Sconfienza, Luca M; Vadalà, Giuseppe; Brambilla, Gelma; Fantini, Luigi; Ciatto, Stefano; Sardanelli, Francesco

    2014-02-01

    To evaluate the performance of the first years since the beginning of a mammographic population-based screening program. Women aged 49-69 were invited biennially for two-view film-screen mammography and double reading without arbitration was performed. Interval cancers (ICs) from 2001 to 2006 were identified using screening archives, local pathology archives, and hospital discharge records. The proportional incidence of IC was determined considering breast cancers expected without screening. Three offsite radiologists experienced in breast cancer screening blindly evaluated mammograms prior to diagnosis, randomly mixed with negative mammograms (1:2 ratio). Cases unrecalled at review were considered as true ICs, those recalled by only one reviewer as minimal signs, and those recalled by two or three reviewers as missed cancers. T and N stage of the reviewed ICs were evaluated and compared. A total of 86,276 first level mammograms were performed. Mean recall rate was 6.8% at first and 4.6% at repeat screening. We had 476 screen-detected cancers and 145 ICs (10 of them ductal carcinomas in situ). Absolute incidence was 17 per 10,000 screening examinations. Invasive proportional incidence was 19% (44/234) in the first year, 39% (91/234) in the second year, and 29% (135/468) in the two-year interval. Of 145 ICs, 130 (90%) were reviewed mixed with 287 negative controls: 55% (71/130) resulted to be true ICs, 24% (31/130) minimal signs, and 22% (28/130) missed cancers. The rate of ICs diagnosed in the first year interval was 21% (15/71) for true ICs, 46% (13/28) for missed cancers, and 39% (12/31) for minimal signs, with a significant difference of true ICs rate compared to missed cancers rate (p=0.012). A higher rate of T3 and T4 stages was found for missed cancers (18%, 5/28) compared to minimal signs (6%, 2/31) or true ICs (8%, 6/71), while the rate of N2 and N3 stage for both minimal signs (19%, 6/31) or missed cancers (25%, 7/28) was higher than that for true ICs (10

  10. Variations in H2O+/H2O ratios toward massive star-forming regions

    NARCIS (Netherlands)

    Wyrowski, F.; van der Tak, F.; Herpin, F.; Baudry, A.; Bontemps, S.; Chavarria, L.; Frieswijk, W.; Jacq, T.; Marseille, M.; Shipman, R.; van Dishoeck, E. F.; Benz, A. O.; Caselli, P.; Hogerheijde, M. R.; Johnstone, D.; Liseau, R.; Bachiller, R.; Benedettini, M.; Bergin, E.; Bjerkeli, P.; Blake, G.; Braine, J.; Bruderer, S.; Cernicharo, J.; Codella, C.; Daniel, F.; di Giorgio, A. M.; Dominik, C.; Doty, S. D.; Encrenaz, P.; Fich, M.; Fuente, A.; Giannini, T.; Goicoechea, J. R.; de Graauw, Th; Helmich, F.; Herczeg, G. J.; Jørgensen, J. K.; Kristensen, L. E.; Larsson, B.; Lis, D.; McCoey, C.; Melnick, G.; Nisini, B.; Olberg, M.; Parise, B.; Pearson, J. C.; Plume, R.; Risacher, C.; Santiago, J.; Saraceno, P.; Tafalla, M.; van Kempen, T. A.; Visser, R.; Wampfler, S.; Yıldız, U. A.; Black, J. H.; Falgarone, E.; Gerin, M.; Roelfsema, P.; Dieleman, P.; Beintema, D.; de Jonge, A.; Whyborn, N.; Stutzki, J.; Ossenkopf, V.

    2010-01-01

    Early results from the Herschel Space Observatory revealed the water cation H2O+ to be an abundant ingredient of the interstellar medium. Here we present new observations of the H2O and H2O+ lines at 1113.3 and 1115.2 GHz using the Herschel Space Observatory toward a sample of high-mass star-forming

  11. An H2A Histone Isotype, H2ac, Associates with Telomere and Maintains Telomere Integrity.

    Directory of Open Access Journals (Sweden)

    Chia-Hsin Su

    Full Text Available Telomeres are capped at the ends of eukaryotic chromosomes and are composed of TTAGGG repeats bound to the shelterin complex. Here we report that a replication-dependent histone H2A isotype, H2ac, was associated with telomeres in human cells and co-immunoprecipitates with telomere repeat factor 2 (TRF2 and protection of telomeres protein 1 (POT1, whereas other histone H2A isotypes and mutations of H2ac did not bind to telomeres or these two proteins. The amino terminal basic domain of TRF2 was necessary for the association with H2ac and for the recruitment of H2ac to telomeres. Depletion of H2ac led to loss of telomeric repeat sequences, the appearance of dysfunctional telomeres, and chromosomal instability, including chromosomal breaks and anaphase bridges, as well as accumulation of telomere-associated DNA damage factors in H2ac depleted cells. Additionally, knockdown of H2ac elicits an ATM-dependent DNA damage response at telomeres and depletion of XPF protects telomeres against H2ac-deficiency-induced G-strand overhangs loss and DNA damage response, and prevents chromosomal instability. These findings suggest that the H2A isotype, H2ac, plays an essential role in maintaining telomere functional integrity.

  12. A comparative examination of tuberculosis immigration medical screening programs from selected countries with high immigration and low tuberculosis incidence rates

    Science.gov (United States)

    2011-01-01

    Background Tuberculosis (TB) in migrants is an ongoing challenge in several low TB incidence countries since a large proportion of TB in these countries occurs in migrants from high incidence countries. To meet these challenges, several countries utilize TB screening programs. The programs attempt to identify and treat those with active and/or infectious stages of the disease. In addition, screening is used to identify and manage those with latent or inactive disease after arrival. Between nations, considerable variation exists in the methods used in migration-associated TB screening. The present study aimed to compare the TB immigration medical examination requirements in selected countries of high immigration and low TB incidence rates. Methods Descriptive study of immigration TB screening programs Results 16 out of 18 eligible countries responded to the written standardized survey and phone interview. Comparisons in specific areas of TB immigration screening programs included authorities responsible for TB screening, the primary objectives of the TB screening program, the yield of detection of active TB disease, screening details and aspects of follow up for inactive pulmonary TB. No two countries had the same approach to TB screening among migrants. Important differences, common practices, common problems, evidence or lack of evidence for program specifics were noted. Conclusions In spite of common goals, there is great diversity in the processes and practices designed to mitigate the impact of migration-associated TB among nations that screen migrants for the disease. The long-term goal in decreasing migration-related introduction of TB from high to low incidence countries remains diminishing the prevalence of the disease in those high incidence locations. In the meantime, existing or planned migration screening programs for TB can be made more efficient and evidenced based. Cooperation among countries doing research in the areas outlined in this study should

  13. A comparative examination of tuberculosis immigration medical screening programs from selected countries with high immigration and low tuberculosis incidence rates

    Directory of Open Access Journals (Sweden)

    Sagebiel Daniel

    2011-01-01

    Full Text Available Abstract Background Tuberculosis (TB in migrants is an ongoing challenge in several low TB incidence countries since a large proportion of TB in these countries occurs in migrants from high incidence countries. To meet these challenges, several countries utilize TB screening programs. The programs attempt to identify and treat those with active and/or infectious stages of the disease. In addition, screening is used to identify and manage those with latent or inactive disease after arrival. Between nations, considerable variation exists in the methods used in migration-associated TB screening. The present study aimed to compare the TB immigration medical examination requirements in selected countries of high immigration and low TB incidence rates. Methods Descriptive study of immigration TB screening programs Results 16 out of 18 eligible countries responded to the written standardized survey and phone interview. Comparisons in specific areas of TB immigration screening programs included authorities responsible for TB screening, the primary objectives of the TB screening program, the yield of detection of active TB disease, screening details and aspects of follow up for inactive pulmonary TB. No two countries had the same approach to TB screening among migrants. Important differences, common practices, common problems, evidence or lack of evidence for program specifics were noted. Conclusions In spite of common goals, there is great diversity in the processes and practices designed to mitigate the impact of migration-associated TB among nations that screen migrants for the disease. The long-term goal in decreasing migration-related introduction of TB from high to low incidence countries remains diminishing the prevalence of the disease in those high incidence locations. In the meantime, existing or planned migration screening programs for TB can be made more efficient and evidenced based. Cooperation among countries doing research in the areas

  14. H2SO4-HNO3-H2O ternary system in the stratosphere

    Science.gov (United States)

    Kiang, C. S.; Hamill, P.

    1974-01-01

    Estimation of the equilibrium vapor pressure over the ternary system H2SO4-HNO3-H2O to study the possibility of stratospheric aerosol formation involving HNO3. It is shown that the vapor pressures for the ternary system H2SO4-HNO3-H2O with weight composition around 70-80% H2SO4, 10-20% HNO3, 10-20% H2O at -50 C are below the order of 10 to the minus 8th mm Hg. It is concluded that there exists more than sufficient nitric acid and water vapor in the stratosphere to participate in ternary system aerosol formation at -50 C. Therefore, HNO3 should be present in stratospheric aerosols, provided that H2SO4 is also present.

  15. Exciting H2 Molecules for Graphene Functionalization

    DEFF Research Database (Denmark)

    Kyhl, Line; Bisson, Regis; Balog, Richard

    2018-01-01

    Hydrogen functionalization of graphene by exposure to vibrationally excited H2 molecules is investigated by combined scanning tunneling microscopy, high resolution electron energy loss spectroscopy, x-ray photoemission spectroscopy measurements and density functional theory calculations. The meas......Hydrogen functionalization of graphene by exposure to vibrationally excited H2 molecules is investigated by combined scanning tunneling microscopy, high resolution electron energy loss spectroscopy, x-ray photoemission spectroscopy measurements and density functional theory calculations....... The measurements reveal that vibrationally excited H2 molecules dissociatively adsorb on graphene on Ir(111) resulting in nano-patterned hydrogen functionalization structures. Calculations demonstrate that the presence of the Ir surface below the graphene lowers the H2 dissociative adsorption barrier and allows...... for the adsorption reaction at energies well below the dissociation threshold of the H-H bond. The first reacting H2 molecule must contain considerable vibrational energy to overcome the dissociative adsorption barrier. However, this initial adsorption further activates the surface resulting in reduced barriers...

  16. H2@Scale Resource and Market Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ruth, Mark

    2017-05-04

    The 'H2@Scale' concept is based on the potential for wide-scale utilization of hydrogen as an energy intermediate where the hydrogen is produced from low cost energy resources and it is used in both the transportation and industrial sectors. H2@Scale has the potential to address grid resiliency, energy security, and cross-sectoral emissions reductions. This presentation summarizes the status of an ongoing analysis effort to quantify the benefits of H2@Scale. It includes initial results regarding market potential, resource potential, and impacts of when electrolytic hydrogen is produced with renewable electricity to meet the potential market demands. It also proposes additional analysis efforts to better quantify each of the factors.

  17. H2 MAGIE: H2 as a Major Agent to Galaxy Interaction and Evolution

    Science.gov (United States)

    Guillard, Pierre

    2010-01-01

    Spitzer space telescope spectroscopy reveal a new class of H2-luminous galaxies with enhanced H2 line emission, but where star formation is strongly suppressed. This is in sharp contrast with what is observed in standard star forming galaxies. These sources are all in active phases of galaxy evolution (galaxy interactions, AGN feedback, gas accretion in galaxy clusters, etc.). Why is H2 present in violent phases of galaxy evolution? How is the H2 emission powered? Why is the H2 gas inefficient at forming stars? What can we learn from these "H2 galaxies" about galaxy formation? This thesis addresses these questions, and discuss the theoretical and observational perspectives of this work (in particular Herschel and JWST).

  18. The Effect of a Designed Respiratory Care Program on the Incidence of Ventilator-Associated Pneumonia: A Clinical Trial

    Directory of Open Access Journals (Sweden)

    Mohammad Abbasinia

    2016-01-01

    Full Text Available Introduction: Ventilator-associated pneumonia is a common complication of mechanical ventilation. This study aimed to evaluate the effect of designed respiratory care program on incidence of ventilator-associated pneumonia (VAP in the mechanically ventilated patient. Methods: In this clinical trial, 64 patients were selected among those who had undergone mechanical ventilation in the ICU of Al‑Zahra Hospital, Isfahan, Iran, using convenience sampling method. The subjects were randomly allocated to intervention and control groups. In the intervention group an upper respiratory care program and in the control group, routine cares were done. Modified Clinical Pulmonary Infection Questionnaire was completed before and on the third, fourth and fifth day of study. Data were analyzed by Chi-square and independent t-test through SPSS Ver.13. Results: The results of this study showed that until the third day of study, the incidence of VAP was similar in the both groups. However, on the fifth day of study, the incidence of VAP in the intervention group was significantly lower than control group. Conclusion: The results of this study showed that an upper respiratory care program reduced the incidence of VAP. Therefore, nurses are recommended to perform this program for prevention of VAP.

  19. Evaluation of the incidence of dental caries in patients with Down syndrome after their insertion in a preventive program

    National Research Council Canada - National Science Library

    Castilho, Aline Rogéria Freire de; Marta, Sara Nader

    2010-01-01

    The objective of this work was to verify the incidence of dental caries by means of the CPO-D, CPO-S, ceo-d and ceo-s indexes in patients with Down syndrome regularly enrolled in a preventive program...

  20. Advanced Colloids Experiment (ACE-H-2)

    Science.gov (United States)

    Meyer, William V.; Sicker, Ron; Chmiel, Alan J.; Eustace, John; LaBarbera, Melissa

    2015-01-01

    Increment 43 - 44 Science Symposium presentation of Advanced Colloids Experiment (ACE-H-2) to RPO. The purpose of this event is for Principal Investigators to present their science objectives, testing approach, and measurement methods to agency scientists, managers, and other investigators.

  1. EPA H2O Software Tool

    Science.gov (United States)

    EPA H2O allows user to: Understand the significance of EGS in Tampa Bay watershed; visually analyze spatial distribution of the EGS in Tampa Bay watershed; obtain map and summary statistics of EGS values in Tampa Bay watershed; analyze and compare potential impacts of development...

  2. Hot hydrogen atom reactions moderated by H2 and He

    Science.gov (United States)

    Aronowitz, S.; Scattergood, T.; Flores, J.; Chang, S.

    1986-01-01

    Photolysis experiments were performed on the H2-CD4-NH3 and He-CD4-NH3 systems. The photolysis (1849 A) involved only NH3. Mixtures of H2:CD4:NH3 included all combinations of the ratios (200,400,800):(10,20,40):4. Two He:CD4:NH3 mixtures were examined where the ratios equalled the combinations 100:(10,20):4. Abstraction of a D from CD4 by the photolytically produced hot hydrogen from ammonia was monitored by mass spectrometric determination of HD. Both experiment and semiempirical hot-atom theory show that H2 is a very poor thermalizer of hot hydrogens with excess kinetic energy of about 2 eV. Applications of the hard-sphere collision model to the H2-CD4-NH3 system resulted in predicted ratios of net HD production to NH3 decomposition that were two orders of magnitude smaller than the experimental ratios. On the other hand, helium is found to be a very efficient thermalizer; here, the classical model yields reasonable agreement with experiments. Application of a semiempirical hot-atom program gave quantitative agreement with experiment for either system.

  3. Reduction in HCV Incidence Among Injection Drug Users Attending Needle and Syringe Programs in Australia: A Linkage Study

    Science.gov (United States)

    Wand, Handan; Topp, Libby; Kaldor, John; Maher, Lisa

    2013-01-01

    Objectives. We examined trends in HCV incident infection among injection drug users (IDUs) attending needle and syringe programs (NSPs) in Australia in 1995 to 2010. Methods. We created a passive retrospective cohort of 724 IDUs who tested negative for HCV antibodies by a simple deterministic method linking partial identifiers to find repeat respondents in annual cross-sectional serosurveillance. Results. We identified 180 HCV seroconversions over the study period, for a pooled incidence density of 17.0 per 100 person-years (95% confidence interval [CI] = 14.68, 19.66). Incidence density declined, from a high of 30.8 per 100 person-years (95% CI = 21.3, 44.6) in 2003 to a low of 4.0 (95% CI = 1.3, 12.3) in 2009. Conclusions. A decline in HCV incidence among Australian IDUs attending NSPs coincided with considerable expansion of harm reduction programs and a likely reduction in the number of IDUs, associated with significant changes in drug markets. Our results demonstrate the capacity of repeat cross-sectional serosurveillance to monitor trends in HCV incidence and provide a platform from which to assess the impact of prevention and treatment interventions. PMID:23763399

  4. The effect of a comprehensive injury audit program on injury incidence in ballet: a 3-year prospective study.

    Science.gov (United States)

    Allen, Nick; Nevill, Alan M; Brooks, John H M; Koutedakis, Yiannis; Wyon, Matthew A

    2013-09-01

    The aim of this study was to determine whether an intervention with individualized conditioning program based on injury history and functional movement screening would be effective in reducing ballet injury incidence. Prospective 3-year epidemiological study. Professional ballet company and its in-house medical facility. Dancers from a professional ballet company over the 3-year study period. Participant numbers ranged from 52 to 58 (year 1: 52; year 2: 58; year 3: 53). The intervention consisted of individual conditioning programs developed using injury history and functional movement screening. Analysis was undertaken of the all dancers who were present in the company during the study period. The significance of change in injuries over a 3-year period was determined using a Poisson distribution model. To determine whether individual conditioning programs resulted in a decrease in injury incidence over the study period. The injury count reduced significantly in years 2 and 3 (P ballet. The implementation of well-structured injury surveillance programs can impact on injury incidence through its influence on intervention programs.

  5. Interactions between metal cations with H 2 in the M-H 2 complexes ...

    Indian Academy of Sciences (India)

    Interactions between metal cations with H2 in the M+- H2 complexes: Performance of DFT and DFT-D methods ... Graduate School of Information Science, Nagoya University, Chukusa-ku, Nagoya 464-8601, Aichi, Japan; Department of Spectroscopy, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 ...

  6. High purity H2/H2O/Ni/SZ electrodes at 500º C

    DEFF Research Database (Denmark)

    Høgh, Jens Valdemar Thorvald; Hansen, Karin Vels; Norrman, Kion

    2013-01-01

    of stabilized zirconia (SZ) with 10, 13 and 18 mol% yttria and one with 6 mol% scandia plus 4 mol% yttria were studied at open circuit voltage at 400-500 C in mixtures of H2/H2O over 46 days. The polarization resistances (Rp) for all samples increased significantly during the first 10-20 days at 500 C...

  7. On Secondary Electron Emission from Solid H2 and D2

    DEFF Research Database (Denmark)

    Schou, Jørgen; Sørensen, H.

    1978-01-01

    The emission of secondary electrons from solid hydrogen (H2 , D2, T2) is often considered to be of importance for the interaction between a fusion plasma and pellets of solid hydrogens. A set-up was therefore built for studies of interactions between energetic particles and solid hydrogens. Studies...... of secondary electron emission (SEE) from solid H2 and D2 were made for incidence of electrons up to 3 keV and for incidence of ions of hydrogen, deuterium, and helium up to 10 keV. The measurements were made for normal incidence, and in some cases also for oblique incidence. The SEE coefficients for solid H2...... is always 0.65-0.70 times that for solid D2. This difference is attributed to different losses to vibrational states in H2 and D2 for the low energy electrons. Measurements were also made on solid para-H2 with both electrons and hydrogen ions. There was no difference from the results for normal H2, which...

  8. H2O Paradox and its Implications on H2O in Moon

    Science.gov (United States)

    Zhang, Youxue

    2017-04-01

    The concentration of H2O in the mantle of a planetary body plays a significant role in the viscosity and partial melting and hence the convection and evolution of the planetary body. Even though the composition of the primitive terrestrial mantle (PTM) is thought to be well known [1-2], the concentration of H2O in PTM remains paradoxial because different methods of estimation give different results [3]: Using H2O/Ce ratio in MORB and OIB and Ce concentration in PTM, the H2O concentration in PTM would be (300÷×1.5) ppm; using mass balance by adding surface water to the mantle [3-4], H2O concentration in PTM would be (900÷×1.3) ppm [2-3]. The inconsistency based on these two seemingly reliable methods is referred to as the H2O paradox [3]. For Moon, H2O contents in the primitive lunar mantle (PLM) estimated from H2O in plagioclase in lunar anorthosite and that from H2O/Ce ratio in melt inclusions are roughly consistent at ˜110 ppm [5-6] even though there is still debate about the volatile depletion trend [7]. One possible solution to the H2O paradox in PTM is to assume that early Earth experienced whole mantle degassing, which lowered the H2O/Ce ratio in the whole mantle but without depleting Ce in the mantle. The second possible solution is that some deep Earth reservoirs with high H2O/Ce ratios have not been sampled by MORB and OIB. Candidates include the transition zone [8] and the D" layer. The third possible solution is that ocean water only partially originated from mantle degassing, but partially from extraterrestrial sources such as comets [9-10]. At present, there is not enough information to determine which scenario is the answer to the H2O paradox. On the other hand, each scenario would have its own implications to H2O in PLM. If the first scenario applies to Moon, because degassed H2O or H2 would have escaped from the lunar surface, the very early lunar mantle could have much higher H2O [11] than that obtained using the H2O/Ce ratio method. The

  9. CFD Recombiner Modelling and Validation on the H2-Par and Kali-H2 Experiments

    Directory of Open Access Journals (Sweden)

    Stéphane Mimouni

    2011-01-01

    Full Text Available A large amount of Hydrogen gas is expected to be released within the dry containment of a pressurized water reactor (PWR, shortly after the hypothetical beginning of a severe accident leading to the melting of the core. According to local gas concentrations, the gaseous mixture of hydrogen, air and steam can reach the flammability limit, threatening the containment integrity. In order to prevent mechanical loads resulting from a possible conflagration of the gas mixture, French and German reactor containments are equipped with passive autocatalytic recombiners (PARs which preventively oxidize hydrogen for concentrations lower than that of the flammability limit. The objective of the paper is to present numerical assessments of the recombiner models implemented in CFD solvers NEPTUNE_CFD and Code_Saturne. Under the EDF/EPRI agreement, CEA has been committed to perform 42 tests of PARs. The experimental program named KALI-H2, consists checking the performance and behaviour of PAR. Unrealistic values for the gas temperature are calculated if the conjugate heat transfer and the wall steam condensation are not taken into account. The combined effects of these models give a good agreement between computational results and experimental data.

  10. [evaluation Of The Incidence Of Dental Caries In Patients With Down Syndrome After Their Insertion In A Preventive Program].

    OpenAIRE

    Castilho, Aline Rogéria Freire de; Marta,Sara Nader

    2015-01-01

    The objective of this work was to verify the incidence of dental caries by means of the CPO-D, CPO-S, ceo-d and ceo-s indexes in patients with Down syndrome regularly enrolled in a preventive program. Twenty four Down syndrome patients of both sexes age range of one to 48 years were examined. The prevalence (initial experimental situation) and incidence (final experimental situation) of dental caries were verified using of the initial and final CPO-D, CPO-S, ceo-d and ceo-s indexes of the par...

  11. Hydrogen Learning for Local Leaders – H2L3

    Energy Technology Data Exchange (ETDEWEB)

    Serfass, Patrick [Technology Transition Corporation, Washington, DC (United States)

    2017-03-30

    The Hydrogen Learning for Local Leaders program, H2L3, elevates the knowledge about hydrogen by local government officials across the United States. The program reaches local leaders directly through “Hydrogen 101” workshops and webinar sessions; the creation and dissemination of a unique report on the hydrogen and fuel cell market in the US, covering 57 different sectors; and support of the Hydrogen Student Design Contest, a competition for interdisciplinary teams of university students to design hydrogen and fuel cell systems based on technology that’s currently commercially available.

  12. [Evaluation of the incidence of dental caries in patients with Down syndrome after their insertion in a preventive program].

    Science.gov (United States)

    Castilho, Aline Rogéria Freire de; Marta, Sara Nader

    2010-10-01

    The objective of this work was to verify the incidence of dental caries by means of the CPO-D, CPO-S, ceo-d and ceo-s indexes in patients with Down syndrome regularly enrolled in a preventive program. Twenty four Down syndrome patients of both sexes age range of one to 48 years were examined. The prevalence (initial experimental situation) and incidence (final experimental situation) of dental caries were verified using of the initial and final CPO-D, CPO-S, ceo-d and ceo-s indexes of the participants. From 24 individual examined, 10 (42.0%) were free of caries. The prevalence of dental caries showed values of CPO-D= 2.33; CPO-S= 3.60; ceo-d= 1.75 e ceo-s= 2.80; while the incidence of caries showed values of 2.33; 3.80; 1.10 e 1.90, respectively. Down syndrome individuals evaluated in this study presented low level of caries and small incidence of new lesions, emphasizing the importance of the maintenance of these patients at preventive programs.

  13. Trends in Inflammatory Breast Carcinoma Incidence and Survival: The Surveillance, Epidemiology, and End Results Program at the National Cancer Institute

    Science.gov (United States)

    Hance, Kenneth W.; Anderson, William F.; Devesa, Susan S.; Young, Heather A.; Levine, Paul H.

    2010-01-01

    Background Inflammatory breast carcinoma (IBC) appears to be a clinicopathologic entity distinct from noninflammatory locally advanced breast cancer (LABC). We examined incidence and survival trends for IBC in Surveillance, Epidemiology, and End Results (SEER) Program data with a case definition designed to capture many of its unique clinical and pathologic characteristics. Methods We analyzed breast cancer cases diagnosed in the SEER 9 Registries (n = 180 224), between 1988 and 2000. Breast cancer cases were categorized using SEER’s “ Extent of Disease” codes in combination with International Classification of Diseases for Oncology morphology code 8530/3 and classified as IBC (n = 3648), LABC (n = 3636), and non-T4 breast cancer (n = 172 940). We compared changes in incidence rates over 3-year intervals by breast cancer subtype and race using SEER*Stat. Survival differences by breast cancer subtype and race were assessed using Kaplan–Meier curves and log-rank statistics. All statistical tests were two-sided. Results Between 1988 and 1990 and 1997 and 1999, IBC incidence rates (per 100 000 woman-years) increased from 2.0 to 2.5 (P10 years, P<.0001). Black women with IBC or LABC had poorer survival than white women with IBC or LABC, respectively (log-rank test, P<.001). Conclusions Throughout the 1990s, IBC incidence rose, and survival improved modestly. Substantial racial differences were noted in age at diagnosis, age-specific incidence rates, and survival outcomes. PMID:15998949

  14. H2@Scale Resource and Market Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ruth, Mark

    2017-07-12

    This presentation overviews progress to date on the H2@Scale resource and market analysis work. The work finds, for example, that hydrogen demand of 60 MMT/yr is possible when transportation and industry are considered; resources are available to meet that demand; using renewable resources would reduce emissions and fossil use by over 15%; further impacts are possible when considering synergistic benefits; additional analysis is underway to improve understanding of potential markets and synergistic impacts; and further analysis will be necessary to estimate impacts due to spatial characteristics, feedback effects in the economy, and inertia characteristics.

  15. Refinements in an Mg/MgH2/H2O-Based Hydrogen Generator

    Science.gov (United States)

    Kindler, Andrew; Huang, Yuhong

    2010-01-01

    Some refinements have been conceived for a proposed apparatus that would generate hydrogen (for use in a fuel cell) by means of chemical reactions among magnesium, magnesium hydride, and steam. The refinements lie in tailoring spatial and temporal distributions of steam and liquid water so as to obtain greater overall energy-storage or energy-generation efficiency than would otherwise be possible. A description of the prior art is prerequisite to a meaningful description of the present refinements. The hydrogen-generating apparatus in question is one of two versions of what was called the "advanced hydrogen generator" in "Fuel-Cell Power Systems Incorporating Mg-Based H2 Generators" (NPO-43554), NASA Tech Briefs, Vol. 33, No. 1 (January 2009), page 52. To recapitulate: The apparatus would include a reactor vessel that would be initially charged with magnesium hydride. The apparatus would exploit two reactions: The endothermic decomposition reaction MgH2-->Mg + H2, which occurs at a temperature greater than or equal to 300 C, and The exothermic oxidation reaction MgH2 + H2O MgO + 2H2, which occurs at a temperature greater than or equal to 330 C.

  16. Osteosarcoma incidence and survival rates from 1973 to 2004: data from the Surveillance, Epidemiology, and End Results Program.

    Science.gov (United States)

    Mirabello, Lisa; Troisi, Rebecca J; Savage, Sharon A

    2009-04-01

    Osteosarcoma, which is the most common primary bone tumor, occurs most frequently in adolescents, but there is a second incidence peak among individuals aged > 60 years. Most osteosarcoma epidemiology studies have been embedded in large analyses of all bone tumors or focused on cases occurring in adolescence. Detailed descriptions of osteosarcoma incidence and survival with direct comparisons among patients of all ages and ethnicities are not available. Frequency, incidence, and survival rates for 3482 patients with osteosarcoma from the National Cancer Institute's population-based Surveillance, Epidemiology, and End Results (SEER) Program between 1973 and 2004 were investigated by age (ages 0-24 years, 25-59 years, and 60 to > or = 85 years), race, sex, pathology subtype, stage, and anatomic site. There were large differences in incidence and survival rates by age. There was a high percentage of osteosarcoma with Paget disease and osteosarcoma as a second or later cancer among the elderly. There was a high percentage of osteosarcoma among patients with Paget disease and osteosarcoma as a second or later cancer among the elderly. Tumor site differences among age groups were noted. Survival rates varied by anatomic site and disease stage and did not improve significantly from 1984 to 2004. This comprehensive, population-based description of osteosarcoma, identified important differences in incidence, survival, pathologic subtype, and anatomic site among age groups, and quantified the impact of osteosarcoma in patients with Paget disease or as a second cancer on incidence and mortality rates. These findings may have implications in understanding osteosarcoma biology and epidemiology. (c) 2009 American Cancer Society

  17. The Incidence of the Tuition-Free High School Program in Japan

    Science.gov (United States)

    Hori, Masahiro; Shimizutani, Satoshi

    2018-01-01

    This paper examines the effect of a tuition-free high school program launched in FY2010 in Japan on the high school enrollment rate and household spending. We have some interesting findings. First, the program contributed to improvement in the high school enrollment rate for poorer households. Second, the program stimulated household spending…

  18. The H2O2-H2O Hypothesis: Extremophiles Adapted to Conditions on Mars?

    Science.gov (United States)

    Houtkooper, Joop M.; Schulze-Makuch, Dirk

    2007-08-01

    The discovery of extremophiles on Earth is a sequence of discoveries of life in environments where it had been deemed impossible a few decades ago. The next frontier may be the Martian surface environment: could life have adapted to this harsh environment? What we learned from terrestrial extremophiles is that life adapts to every available niche where energy, liquid water and organic materials are available so that in principle metabolism and propagation are possible. A feasible adaptation mechanism to the Martian surface environment would be the incorporation of a high concentration of hydrogen peroxide in the intracellular fluid of organisms. The H2O2-H2O hypothesis suggests the existence of Martian organisms that have a mixture of H2O2 and H2O instead of salty water as their intracellular liquid (Houtkooper and Schulze-Makuch, 2007). The advantages are that the freezing point is low (the eutectic freezes at 56.5°C) and that the mixture is hygroscopic. This would enable the organisms to scavenge water from the atmosphere or from the adsorbed layers of water molecules on mineral grains, with H2O2 being also a source of oxygen. Moreover, below its freezing point the H2O2-H2O mixture has the tendency to supercool. Hydrogen peroxide is not unknown to biochemistry on Earth. There are organisms for which H2O2 plays a significant role: the bombardier beetle, Brachinus crepitans, produces a 25% H2O2 solution and, when attacked by a predator, mixes it with a fluid containing hydroquinone and a catalyst, which produces an audible steam explosion and noxious fumes. Another example is Acetobacter peroxidans, which uses H2O2 in its metabolism. H2O2 plays various other roles, such as the mediation of physiological responses such as cell proliferation, differentiation, and migration. Moreover, most eukaryotic cells contain an organelle, the peroxisome, which mediates the reactions involving H2O2. Therefore it is feasible that in the course of evolution, water-based organisms

  19. Incidence of cervical lesions in Danish women before and after implementation of a national HPV vaccination program

    DEFF Research Database (Denmark)

    Baldur-Felskov, Birgitte; Dehlendorff, Christian; Junge, Jette

    2014-01-01

    PURPOSE: Approximately 7% of cervical cancers and about 50% of high-grade cervical precursor lesions are caused by human papillomavirus (HPV) types 16 and 18. Denmark introduced the quadrivalent HPV vaccine into the vaccination program for 12-year-old girls in 2009 supplemented by a first catch......-up program for 13-15-year-old girls in 2008, and a second program for women up to the age of 27 years in 2012; all with high vaccination coverage. The aim of this study was to evaluate the effectiveness of the vaccine by comparing the incidence trends of cervical lesions before and after its introduction......+) and cervical intraepithelial neoplasia grade 2 or worse (CIN2+) increased in all age groups in 2000-2010. After introduction of the quadrivalent HPV vaccine into the vaccination program, the incidence of atypia+ decreased significantly in women younger than 18 years (EAPC -33.4%; 95% CI -49.6; -12.0) and in 18...

  20. Kinetic Energy Distribution of H(2p) Atoms from Dissociative Excitation of H2

    Science.gov (United States)

    Ajello, Joseph M.; Ahmed, Syed M.; Kanik, Isik; Multari, Rosalie

    1995-01-01

    The kinetic energy distribution of H(2p) atoms resulting from electron impact dissociation of H2 has been measured for the first time with uv spectroscopy. A high resolution uv spectrometer was used for the measurement of the H Lyman-alpha emission line profiles at 20 and 100 eV electron impact energies. Analysis of the deconvolved 100 eV line profile reveals the existence of a narrow line peak and a broad pedestal base. Slow H(2p) atoms with peak energy near 80 meV produce the peak profile, which is nearly independent of impact energy. The wings of H Lyman-alpha arise from dissociative excitation of a series of doubly excited Q(sub 1) and Q(sub 2) states, which define the core orbitals. The fast atom energy distribution peaks at 4 eV.

  1. Comparison of the Incidence of Perinatal Asphyxia before and after the Health Improvement Program in Bentolhoda Hospital of Bojnurd, Iran

    Directory of Open Access Journals (Sweden)

    Mahvan Khodaparast

    2016-12-01

    Full Text Available Background: Perinatal asphyxia is a common cause of infant morbidity and mortality and long-term neurological disabilities. Due to the high costs of admission, a large proportion of births and neonatal deaths occur in non-hospital settings. This study aimed to evaluate the incidence rate of perinatal asphyxia before and after the implementation of the health improvement program. Methods: This descriptive-analytical study was conducted on all the infants with moderate and severe asphyxia during April 2013-2015. Subjects were divided into two groups of A and B (born after and before the health improvement program, respectively. Maternal and neonatal data were recorded in checklists and compared between these  groups. Data analysis was performed in SPSS version 17. Results: In total, 111 asphyxiated neonates were classified into two groups of A and B, and incidence rate of asphyxia was estimated at 0.54% and 1.05%, respectively. Severe asphyxia was observed in 35.7% and 28.9% of the infants in groups A and B, respectively. Moreover, mean duration of mechanical ventilation was 25 and 79 hours in groups A and B, respectively. Conclusion: According to the results of this study, implementation of the health improvement program reduced the incidence of perinatal asphyxia. In addition, number of cesarean cases due to previous C-section was observed to decrease. Therefore, it could be concluded that high-quality resuscitation efforts and restricted rules in the health improvement program lower the risk of long-term complications in asphyxiated neonates. However, no significant difference was observed in the mortality rate of the asphyxiated newborns in this study.

  2. Impact of a standardized hand hygiene program on the incidence of nosocomial infection in very low birth weight infants.

    Science.gov (United States)

    Capretti, Maria Grazia; Sandri, Fabrizio; Tridapalli, Elisabetta; Galletti, Silvia; Petracci, Elisabetta; Faldella, Giacomo

    2008-08-01

    This study examined the effects of a standardized hand hygiene program on the rate of nosocomial infection (NI) in very low birth weight (VLBW) infants (birth weight antimicrobial soap (4% chlorhexidine gluconate) and alcohol-based hand rubs. NI after 72 hours of life was detected in 16 of the 85 VLBW infants in the first period and in 5 of the 80 VLBW infants in the second period. The rate of central venous catheter colonization was significantly lower in the second period (5.8%) than in the first period (16.6%). In our NICU, the incidence of NI in VLBW infants was significantly reduced after the introduction of a standardized handwashing protocol. In our experience, a proper hand hygiene program can save approximately 10 NI episodes/year, at a cost of $10,000 per episode. Therefore, improving hand hygiene practice is a cost-effective program in the NICU.

  3. Effects of a recovery-oriented cognitive therapy training program on inpatient staff attitudes and incidents of seclusion and restraint.

    Science.gov (United States)

    Chang, Nadine A; Grant, Paul M; Luther, Lauren; Beck, Aaron T

    2014-05-01

    We investigated the feasibility of implementing a recovery-oriented cognitive therapy (CT-R) milieu training program in an urban acute psychiatric inpatient unit. Over a 1-month period, 29 staff members learned short-term CT-R strategies and techniques in an 8-h workshop. Trainees' perceptions of CT-R, beliefs about the therapeutic milieu, and attitudes about working with individuals with psychosis were evaluated both before the workshop and 6 months after the workshop had been completed. Incidents of seclusion and restraint on the unit were also tallied prior to and after the training. Results indicate that staff perceptions of CT-R and their beliefs about the therapeutic environment significantly improved, whereas staff attitudes towards individuals with psychosis remained the same. Incidents of seclusion and restraint also decreased after the training. These findings provide evidence that CT-R training is feasible and can improve the therapeutic milieu of an acute psychiatric inpatient unit.

  4. FLYING-WATER Renewables-H2-H2O TERRAFORMING: PERMANENT Drought(s)-Elimination FOREVER!!!

    Science.gov (United States)

    Ertl, G.; Alefeld, G.; Youdelis, W.; Radd, H.; Oertle, G.; Siegel, Edward

    2011-03-01

    "H2O H2O everywhere; ne'er a drop to drink"[Coleridge(1798)]; now: "H2 H2 everywhere; STILL ne'er a drop to drink": ONLY H2 (or methane CH4) can be FLYING-WATER(F-W) chemical-rain-in-pipelines Hindenberg-effect (H2-UP;H2O-DOWN): {O/H2O}=[16]/[18] 90 % ; O already in air uphill; NO H2O pumping need! In global-warming driven H2O-starved glacial-melting world, rescue is possible ONLY by Siegel [{3rd Intl. Conf. Alt.-Energy }(1980)-vol.5/p.459!!!] Renewables-H2-H2O purposely flexible versatile agile customizable scaleable retrofitable integrated operating-system. Rosenfeld[Science 315,1396(3/9/2007)]-Biello [Sci.Am.(3/9/2007)] crucial geomorph-ology which ONLY maximal-buoyancy H2 can exploit, to again make "Mountains into Fountains", ``upthrust rocks trapping the clouds to precipitate their rain/snow/H2O'': "terraforming"(and ocean-rebasificaton!!!) Siegel proprietary magnetic-hydrogen-valve (MHV) permits H2 flow in already in-ground dense BCC/ferritic-steels pipelines-network (NO new infrastructure) counters Tromp[Science 300,1740(2003)] dire warning of global-pandemics (cancers/ blindness/famine) Hydrogen-economy CATASTROPHIC H2 ozone-layer destruction sobering cavat to dangerous H2-automotion-economy panacea hype!!!

  5. Effectiveness of a stress management pilot program aimed at reducing the incidence of sports injuries in young football (soccer) players.

    Science.gov (United States)

    Olmedilla-Zafra, Aurelio; Rubio, Victor J; Ortega, Enrique; García-Mas, Alexandre

    2017-03-01

    Several attempts to reduce the incidence of sport injuries using psychosocial interventions produced fruitful, although inconclusive results. This paper presents the effectiveness and implementation issues of a pilot 3-month stress-management and muscle relaxation program aimed at reducing sport injury incidence. Pre-post treatment-non treatment group comparison. The program was administered by a trained psychologist on a once-a-week, 1-h session basis. Seventy-four male soccer players from four National Youth league teams voluntarily participated. Teams were randomly assigned to either treatment/non-treatment group. Injury protocol, Self-monitoring cards, Athletes' satisfaction and commitment survey, Coaches' interview. Group main effect and Time-Group interaction effect were both statistically significant, F(1,60) = 8.30, p = 0.005, η2p = 0.121, with the average number of injuries larger in the post-treatment phase of non-treatment group (p = 0.005, η2p = 0.077). There was a significant decrease in the average number of injuries for the intervention group before and after implementing the program (p sport injuries, with a high level of satisfaction and commitment from the athletes, as well as high acceptance from the coaches. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. 20 CFR 655.132 - H-2A labor contractor (H-2ALC) filing requirements.

    Science.gov (United States)

    2010-04-01

    ... LABOR TEMPORARY EMPLOYMENT OF FOREIGN WORKERS IN THE UNITED STATES Labor Certification Process for Temporary Agricultural Employment in the United States (H-2A Workers) Application for Temporary Employment... applicable Federal, State, or local laws and regulations and must provide, at a minimum, the same vehicle...

  7. Interactions between metal cations with H2 in the M - H2 complexes ...

    Indian Academy of Sciences (India)

    Cu. +. , Zn. +. ) and H2 molecule have been investigated in detail using dispersion-corrected and -uncorrected double hybrid density functional (DHDF), gradient cor- rected density ... works (MOFs) and zeolites.5 In a recent article6 we have studied the .... term is swapped by the modified Perdew-Wang (mPW) functional of ...

  8. H2O2 space shuttle APU

    Science.gov (United States)

    1975-01-01

    A cryogenic H2-O2 auxiliary power unit (APU) was developed and successfully demonstrated. It has potential application as a minimum weight alternate to the space shuttle baseline APU because of its (1) low specific propellant consumption and (2) heat sink capabilities that reduce the amount of expendable evaporants. A reference system was designed with the necessary heat exchangers, combustor, turbine-gearbox, valves, and electronic controls to provide 400 shp to two aircraft hydraulic pumps. Development testing was carried out first on the combustor and control valves. This was followed by development of the control subsystem including the controller, the hydrogen and oxygen control valves, the combustor, and a turbine simulator. The complete APU system was hot tested for 10 hr with ambient and cryogenic propellants. Demonstrated at 95 percent of design power was 2.25 lb/hp-hr. At 10 percent design power, specific propellant consumption was 4 lb/hp-hr with space simulated exhaust and 5.2 lb/hp-hr with ambient exhaust. A 10 percent specific propellant consumption improvement is possible with some seal modifications. It was demonstrated that APU power levels could be changed by several hundred horsepower in less than 100 msec without exceeding allowable turbine inlet temperatures or turbine speed.

  9. School Nutrition Programs and the Incidence of Childhood Obesity. NBER Working Paper No. 14297

    Science.gov (United States)

    Millimet, Daniel L.; Tchernis, Rusty; Husain, Muna

    2008-01-01

    In light of the recent rise in childhood obesity, the School Breakfast Program (SBP) and National School Lunch Program (NSLP) have received renewed attention. Using panel data on over 13,500 primary school students, we assess the relationship between SBP and NSLP participation and (relatively) long-run measures of child weight. After documenting a…

  10. Methodological aspects of breath hydrogen (H2) analysis. Evaluation of a H2 monitor and interpretation of the breath H2 test

    DEFF Research Database (Denmark)

    Rumessen, J J; Kokholm, G; Gudmand-Høyer, E

    1987-01-01

    The reliability of end-expiratory hydrogen (H2) breath tests were assessed and the significance of some important pitfalls were studied, using a compact, rapid H2-monitor with electrochemical cells. The H2 response was shown to be linear and stable. The reproducibility of the breath collection...... were studied in 10 healthy adults during a 4-month period and they showed very marked inter- and intra-individual variability (16% above 40 p.p.m.). Initial peaks (early, short-lived H2 rises unrelated to carbohydrate malabsorption) were identified in 25% of the breath tests (in 4% above 20 p.......p.m). It is concluded that the technique used for interval sampling of end-expiratory breath samples for H2 concentration gives reliable results. The biological significance of H2 concentration increments can only be evaluated if the limitations of the technical procedures and the individual ability to produce H2...

  11. Phase transition and optoelectronic properties of MgH2

    Science.gov (United States)

    Nayak, Vikas; Verma, U. P.

    2016-05-01

    In this article, structural and electronic properties of MgH2 have been studied. The aim behind this study was to find out the ground state crystal structure of MgH2. For the purpose, density functional theory (DFT)-based full-potential linearized augmented plane wave (FP-LAPW) calculations have been performed in three different space groups: P42/mnm (α-MgH2), Pa3 (β-MgH2) and Pbcn (γ-MgH2). It has been found that the ground state structure of MgH2 is α-MgH2. The present study shows that α-MgH2 transforms into γ-MgH2 at a pressure of 0.41 GPa. After further increase in pressure, γ-MgH2 transforms into β-MgH2 at a pressure of 3.67 GPa. The obtained results are in good agreement with previously reported experimental data. In all the studied phases, the behavior of MgH2 is insulating and its optical conductivity is around 6.0 eV. The α-MgH2 and γ-MgH2 are anisotropic materials while β-MgH2 is isotropic in nature.

  12. Histone H2A and H2B are monoubiquitinated at AID-targeted loci.

    Directory of Open Access Journals (Sweden)

    Glen M Borchert

    Full Text Available BACKGROUND: Somatic hypermutation introduces base substitutions into the rearranged and expressed immunoglobulin (Ig variable regions to promote immunity. This pathway requires and is initiated by the Activation Induced Deaminase (AID protein, which deaminates cytidine to produce uracils and UG mismatches at the Ig genes. Subsequent processing of uracil by mismatch repair and base excision repair factors contributes to mutagenesis. While selective for certain genomic targets, the chromatin modifications which distinguish hypermutating from non-hypermutating loci are not defined. METHODOLOGY/PRINCIPAL FINDINGS: Here, we show that AID-targeted loci in mammalian B cells contain ubiquitinated chromatin. Chromatin immunoprecipitation (ChIP analysis of a constitutively hypermutating Burkitt's B cell line, Ramos, revealed the presence of monoubiquitinated forms of both histone H2A and H2B at two AID-associated loci, but not at control loci which are expressed but not hypermutated. Similar analysis using LPS activated primary murine splenocytes showed enrichment of the expressed V(H and Sgamma3 switch regions upon ChIP with antibody specific to AID and to monoubiquitinated H2A and H2B. In the mechanism of mammalian hypermutation, AID may interact with ubiquitinated chromatin because confocal immunofluorescence microscopy visualized AID colocalized with monoubiquitinated H2B within discrete nuclear foci. CONCLUSIONS/SIGNIFICANCE: Our results indicate that monoubiquitinated histones accompany active somatic hypermutation, revealing part of the histone code marking AID-targeted loci. This expands the current view of the chromatin state during hypermutation by identifying a specific nucleosome architecture associated with somatic hypermutation.

  13. The first 7 years of the metropolitan fire brigade emergency responder program – an overview of incidents attended

    Directory of Open Access Journals (Sweden)

    Malcolm J Boyle

    2010-10-01

    Full Text Available Malcolm J Boyle1, Brett Williams1, Colin Bibby2, Allan Morton2, Chris Huggins11Department of Community Emergency Health and Paramedic Practice, Monash University, Frankston, Victoria, Australia; 2Emergency Medical Services, Metropolitan Fire and Emergency Services Board, Richmond, Victoria, AustraliaPurpose: The Melbourne Metropolitan Fire and Emergency Services Board (MFESB was the first fire service in Australia to implement a service-wide emergency medical response (EMR program in 2001. No additional scientific analysis of the first responder program has been reported since the pilot program. The objective of this study was to report the first 7 years of responses by firefighters as first responders.Patients and methods: The MFESB have three separate datasets with cardiac arrest information: (i callout record; (ii patient care record; and (iii cardiac arrest record, including data from the automatic external defibrillator. Descriptive statistics were used to summarize the demographic and specific outcome data. Ethics approval was granted.Results: A total of 8227 incidents were attended over the first 7 years. The most incidents attended were cardiac arrest 54% (n = 4450 followed by other medical 19% (n = 1579, and drug overdose 11% (n = 908; the remainder were <10% each. Sixty-three percent of incidents involved males. Average age was 57.2 years, median age 63 years, range from <1 month to 101 years; average response time was 6.1 minutes, median response time 5.6 minutes, range from 9 seconds to 31.5 minutes. Firefighters provided “initial care” in 57% and assisted in 26% of the incidents. Firefighters spent on average 4.8 minutes with the patient before handing over to paramedics; median 3.9 minutes, range of a few seconds to 39.2 minutes.Conclusion: This study suggests that the MFESB EMR program is providing firefighter first responders to emergency situations in a short timeframe to assist the ambulance service.Keywords: emergency

  14. Scattering of near-zero-energy electrons and positrons by H2

    KAUST Repository

    Zhang, J.-Y.

    2014-04-15

    The parameters for S-wave elastic scattering of near-zero-energy electrons and positrons by H2 molecules are calculated using the stabilization method with explicitly correlated Gaussians. The confined variational method is applied to optimize the Gaussians to describe the short-range interaction of incident e± with H2 in the fixed-nuclei approximation. For e+-H2 scattering the scattering length of previous work [Phys. Rev. Lett. 103, 223202 (2009)] is substantially improved. More importantly, for e−-H2 scattering, from first principles, the scattering length is computed as a function of the internuclear distance. In the case that the two nuclei are at the equilibrium distance the results are in a good agreement with values derived from fitting experimental total and diffusion cross sections to the modified effective range theory.

  15. Review of literature and practices for incident management programs : technical report.

    Science.gov (United States)

    2016-06-01

    The project team examined project evaluations, best practice summaries, and synthesis documents, and derived a summary of key elements of programs to speed the time to find and clear stalled vehicles and crashes from freeway shoulders and main lanes....

  16. Trends in incidence rates of tobacco-related cancer, selected areas, SEER Program, United States, 1992-2004.

    Science.gov (United States)

    Polednak, Anthony P

    2009-01-01

    Recent trends in incidence rates for tobacco-related cancers may vary geographically because of variation in socioeconomic status and in history of comprehensive state tobacco control programs (starting with California in 1989). Recent trends in risk factors are likely to affect cancer incidence rates at the youngest ages Trends in age-adjusted incidence rates for cancers most strongly associated with tobacco (ie, lung, oral cavity-pharynx, and bladder cancers) were analyzed for 1992 through 2004 in 11 areas (the states of Connecticut, Hawaii, Iowa, Utah, and New Mexico, and the metropolitan areas of Atlanta, Georgia; Detroit, Michigan; Los Angeles County, California; San Francisco-Oakland, California; San Jose-Monterey, California; and Seattle-Puget Sound, Washington) in the Surveillance, Epidemiology and End Results (SEER) Program. The 8 states differed in poverty rate of the population and in history of statewide tobacco control efforts as measured by an initial outcomes index (IOI) for the 1990s and a strength of tobacco control (SoTC) index for 1999 through 2000. Annual percentage change (APC) in incidence rate was calculated for whites and blacks separately and by sex for each SEER area. Among whites, the largest declines for lung cancer were in the 3 SEER areas of California, which were the only areas with significant (negative) APCs for oral cavity-pharynx cancer (but not for bladder cancer). For blacks, significant (negative) APCs for both lung and oral cavity-pharynx cancers were found in 4 of 5 areas with useful data but only 1 of 3 areas for bladder cancer. The strongest correlations of APCs for whites were for lung and oral cavity-pharynx cancers with the IOIs for the early 1990s and with the SoTC (due to the influence of California, which had the highest SoTC). Lung and oral cavity-pharynx cancer incidence rates among whites aged 15 to 54 years declined more in California than in other areas, possibly because of comprehensive state tobacco control

  17. SU-C-BRD-05: Implementation of Incident Learning in the Safety and Quality Management of Radiotherapy: The Primary Experience in a New Established Program with Advanced Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Yang, R; Wang, J [Peking University Third Hospital, Beijing, Beijing (China)

    2014-06-15

    Purpose: To explore the implementation and effectiveness of incident learning for the safety and quality of radiotherapy in a new established radiotherapy program with advanced technology. Methods: Reference to the consensus recommendations by American Association of Physicist in Medicine, an incident learning system was specifically designed for reporting, investigating, and learning of individual radiotherapy incidents in a new established radiotherapy program, with 4D CBCT, Ultrasound guided radiotherapy, VMAT, gated treatment delivered on two new installed linacs. The incidents occurring in external beam radiotherapy from February, 2012 to January, 2014 were reported. Results: A total of 33 reports were analyzed, including 28 near misses and 5 incidents. Among them, 5 originated in imaging for planning, 25 in planning, 1 in plan transfer, 1 in commissioning and 1 in treatment delivery. Among them, three near misses originated in the safety barrier of the radiotherapy process. In terms of error type, 1 incident was classified as wrong patient, 7 near misses/incidents as wrong site, 6 as wrong laterality, 5 as wrong dose, 7 as wrong prescription, and 7 as suboptimal plan quality. 5 incidents were all classified as grade 1/2 of dosimetric severity, 1 as grade 0, and the other 4 as grade 1 of medical severity. For the causes/contributory factors, negligence, policy not followed, inadequate training, failure to develop an effective plan, and communication contributed to 19, 15, 12, 5 and 3 near misses/incidents, respectively. The average incident rate per 100 patients treated was 0.4; this rate fell to 0.28% in the second year from 0.56% in the first year. The rate of near miss fell to 1.24% from 2.22%. Conclusion: Effective incident learning can reduce the occurrence of near miss/incidents, enhance the culture of safety. Incident learning is an effective proactive method for improving the quality and safety of radiotherapy.

  18. Full-dimensional, high-level ab initio potential energy surfaces for H2(H2O) and H2(H2O)2 with application to hydrogen clathrate hydrates.

    Science.gov (United States)

    Homayoon, Zahra; Conte, Riccardo; Qu, Chen; Bowman, Joel M

    2015-08-28

    New, full-dimensional potential energy surfaces (PESs), obtained using precise least-squares fitting of high-level electronic energy databases, are reported for intrinsic H2(H2O) two-body and H2(H2O)2 three-body potentials. The database for H2(H2O) consists of approximately 44 000 energies at the coupled cluster singles and doubles plus perturbative triples (CCSD(T))-F12a/haQZ (aug-cc-pVQZ for O and cc-pVQZ for H) level of theory, while the database for the three-body interaction consists of more than 36 000 energies at the CCSD(T)-F12a/haTZ (aug-cc-pVTZ for O, cc-pVTZ for H) level of theory. Two precise potentials are based on the invariant-polynomial technique and are compared to computationally faster ones obtained via "purified" symmetrization. All fits use reduced permutational symmetry appropriate for these non-covalent interactions. These intrinsic potentials are employed together with existing ones for H2, H2O, and (H2O)2, to obtain full PESs for H2(H2O) and H2(H2O)2. Properties of these full PESs are presented, including a diffusion Monte Carlo calculation of the zero-point energy and wavefunction, and dissociation energy of the H2(H2O) dimer. These PESs together with an existing one for water clusters are used in a many-body representation of the PES of hydrogen clathrate hydrates, illustrated for H2@(H2O)20. An analysis of this hydrate is presented, including the electronic dissociation energy to remove H2 from the calculated equilibrium structure.

  19. Incidence and age-specific presentation of restrictive eating disorders in children: a Canadian Paediatric Surveillance Program study.

    Science.gov (United States)

    Pinhas, Leora; Morris, Anne; Crosby, Ross D; Katzman, Debra K

    2011-10-01

    To document and describe the incidence and age-specific presentation of early-onset restrictive eating disorders in children across Canada. Surveillance study. Cases were ascertained through the Canadian Paediatric Surveillance Program by surveying approximately 2453 Canadian pediatricians (a 95% participation rate) monthly during a 2-year period. Canadian pediatric practices. Pediatricians and pediatric subspecialists. A description of clinical presentations and characteristics of eating disorders in this population and the incidence of restrictive eating disorders in children. The incidence of early-onset restrictive eating disorders in children aged 5 to 12 years seen by pediatricians was 2.6 cases per 100 000 person-years. The ratio of girls to boys was 6:1, and 47.1% of girls and 54.5% of boys showed signs of growth delay. Forty-six percent of children were below the 10th percentile for body mass index, 34.2% were initially seen with unstable vital signs, and 47.2% required hospital admission. Only 62.1% of children met criteria for anorexia nervosa. Although children with anorexia nervosa were more likely to be medically compromised, some children who did not meet criteria for anorexia nervosa were equally medically unstable. Young children are seen with clinically significant restrictive eating disorders, with the incidence exceeding that of type 2 diabetes mellitus. These eating disturbances can result in serious medical consequences, ranging from growth delay to unstable vital signs, which can occur in the absence of weight loss or other restrictive eating disorder symptoms.

  20. Incidence of hepatocellular carcinoma in children in Khon Kaen before and after national hepatitis B vaccine program.

    Science.gov (United States)

    Wichajarn, Khunton; Kosalaraksa, Pope; Wiangnon, Surapon

    2008-01-01

    Hepatitis B virus infection is one of the most important risk factors for hepatocellular carcinoma. Hepatitis B vaccination has been obligatory in the Expanded Program on Immunization (EPI) in Khon Kaen since 1990. To compare the incidence of hepatocellular carcinoma in children in Khon Kaen province before and after the introduction of national hepatitis B vaccination program. Cases of liver tumors in children under 18, diagnosed during 1985-2007, were retrieved from the population-based cancer registry of Khon Kaen. Patients were divided into 2 groups, vaccinated and non-vaccinated with hepatitis B vaccine regarding the year of birth before or after 1990. Patients with diagnosis of liver cancer from any basis of diagnosis in population-based registration, except hepatoblastoma, were included. Patients without verified histology were assumed as having hepatocellular carcinoma if the age at diagnosis was over 10. Age-standardized incidence rates (ASRs) were analyzed and expressed as numbers per 1,000,000 population. Fifteen patients aged 13 to 18 years were included in this study. The mean and median ages at diagnosis were 15.7 and 15 years respectively. Four children had a verified histology (age 14 to 18 years, median and mean = 16). The remaining 11 patients were diagnosed based on history and physical examination, radiology and death certificate, at the aged of 13 to 18 years. The ASRs for liver cancer in children over 10 years of age of non-vaccinated and vaccinated children were 0.88 and 0.07 per million respectively (p = 0.039). When calculated by including children at or older the 5 years of age, the ASRs for non-vaccinated and vaccinated cases were 0.97 and 0.24 per million respectively (p = 0.007). The incidence of hepatocellular carcinoma is significantly lower in Thai children who receive hepatitis B vaccine at birth.

  1. Hydrogen constituents of the mesosphere inferred from positive ions - H2O, CH4, H2CO, H2O2, and HCN

    Science.gov (United States)

    Kopp, E.

    1990-01-01

    The concentrations in the mesosphere of H2O, CH4, H2CO, H2O2, and HCN were inferred from data on positive ion compositions, obtained from one mid-latitude and four high-latitude rocket flights. The inferred concentrations were found to agree only partially with the ground-based microwave measurements and/or model prediction by Garcia and Solomon (1985). The CH4 concentration was found to vary between 70 and 4 ppb in daytime and 900 and 100 ppbv at night, respectively. Unexpectedly high H2CO concentrations were obtained, with H2CO/H2O ratios between 0.0006 and 0.1, and a mean HCN volume mixing ratio of 6 x 10 to the -10th was inferred.

  2. Significant Reduction in the Incidence of Genital Warts in Young Men 5 Years into the Danish Human Papillomavirus Vaccination Program for Girls and Women

    DEFF Research Database (Denmark)

    Bollerup, Signe; Baldur-Felskov, Birgitte; Blomberg, Maria

    2016-01-01

    BACKGROUND: Denmark introduced the quadrivalent human papillomavirus vaccine into the vaccination program for 12- to 15-year-old girls in 2008 to 2009. In 2012, the program was supplemented with a catch-up program for women aged up to 27 years. We evaluated the effectiveness of the Danish...... percentage change (EAPC) was calculated by Poisson regression. RESULTS: Genital wart incidence was either stable or increased in both sexes in 2006 to 2008. After introduction of the vaccination program, GW incidence decreased significantly in women aged 12 to 35 years and men aged 12 to 29 years, with rapid...... decreasing incidence of GWs in women up to 35 years of age after the start of the human papillomavirus vaccination program. A similar pattern was observed for men aged 12 to 29 years, indicating substantial herd protection....

  3. Use of risk projection models to estimate mortality and incidence from radiation-induced breast cancer in screening programs

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, M [Chemical and Nuclear Engineering Department, Polytechnic University of Valencia, Camino de Vera s/n 46022 Valencia (Spain); Ferrer, S [Chemical and Nuclear Engineering Department, Polytechnic University of Valencia, Camino de Vera s/n 46022 Valencia (Spain); Villaescusa, J I [Radiation Protection Service, Hospital Universitario La Fe, Avda Campanar, 21 46009 Valencia (Spain); Verdu, G [Chemical and Nuclear Engineering Department, Polytechnic University of Valencia, Camino de Vera s/n 46022 Valencia (Spain); Salas, M D [Public Health General Direction, Conselleria de Sanitat de Valencia, C/Micer Masco, 31 46021 Valencia (Spain); Cuevas, M D [Assistential Service General Direction, Conselleria de Sanitat de Valencia, C/Micer Masco, 31 46021 Valencia (Spain)

    2005-02-07

    The authors report on a method to calculate radiological risks, applicable to breast screening programs and other controlled medical exposures to ionizing radiation. In particular, it has been applied to make a risk assessment in the Valencian Breast Cancer Early Detection Program (VBCEDP) in Spain. This method is based on a parametric approach, through Markov processes, of hazard functions for radio-induced breast cancer incidence and mortality, with mean glandular breast dose, attained age and age-at-exposure as covariates. Excess relative risk functions of breast cancer mortality have been obtained from two different case-control studies exposed to ionizing radiation, with different follow-up time: the Canadian Fluoroscopy Cohort Study (1950-1987) and the Life Span Study (1950-1985 and 1950-1990), whereas relative risk functions for incidence have been obtained from the Life Span Study (1958-1993), the Massachusetts tuberculosis cohorts (1926-1985 and 1970-1985), the New York post-partum mastitis patients (1930-1981) and the Swedish benign breast disease cohort (1958-1987). Relative risks from these cohorts have been transported to the target population undergoing screening in the Valencian Community, a region in Spain with about four and a half million inhabitants. The SCREENRISK software has been developed to estimate radiological detriments in breast screening. Some hypotheses corresponding to different screening conditions have been considered in order to estimate the total risk associated with a woman who takes part in all screening rounds. In the case of the VBCEDP, the total radio-induced risk probability for fatal breast cancer is in a range between [5 x 10{sup -6}, 6 x 10{sup -4}] versus the natural rate of dying from breast cancer in the Valencian Community which is 9.2 x 10{sup -3}. The results show that these indicators could be included in quality control tests and could be adequate for making comparisons between several screening programs.

  4. Analysis list: Suv39h2 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Suv39h2 Pluripotent stem cell + mm9 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/Suv...39h2.1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/Suv39h2.5.tsv http://dbarchive.bi...osciencedbc.jp/kyushu-u/mm9/target/Suv39h2.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/Suv39h

  5. Incidence of Caries in Babies After 15 Months of an Educative/Preventive Program

    OpenAIRE

    Eunice KUHN; Denise Stadler WAMBIER

    2007-01-01

    Objective: To evaluate an educative/preventive program to control caries disease in 160 babies, ages ranging from 1 to 21 months. Method: The selected children, healthy and without caries, were examined once every three months during 15 months. In each appointment, the biofilm was removed with gauze and a baby’s toothbrush, according to the child’s age. After visual examination, the number of teeth and eventual alterations were recorded. Mothers were guided to perform suitable preventive act...

  6. 45 CFR 1626.11 - H-2 agricultural workers.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 4 2010-10-01 2010-10-01 false H-2 agricultural workers. 1626.11 Section 1626.11... ON LEGAL ASSISTANCE TO ALIENS § 1626.11 H-2 agricultural workers. (a) Nonimmigrant agricultural workers admitted under the provisions of 8 U.S.C. 1101(a)(15)(h)(ii), commonly called H-2 workers, may be...

  7. Characterization of the histone H2A.Z-1 and H2A.Z-2 isoforms in vertebrates

    Directory of Open Access Journals (Sweden)

    Helbing Caren C

    2009-12-01

    Full Text Available Abstract Background Within chromatin, the histone variant H2A.Z plays a role in many diverse nuclear processes including transcription, preventing the spread of heterochromatin and epigenetic transcriptional memory. The molecular mechanisms of how H2A.Z mediates its effects are not entirely understood. However, it is now known that H2A.Z has two protein isoforms in vertebrates, H2A.Z-1 and H2A.Z-2, which are encoded by separate genes and differ by 3 amino acid residues. Results We report that H2A.Z-1 and H2A.Z-2 are expressed across a wide range of human tissues, they are both acetylated at lysine residues within the N-terminal region and they exhibit similar, but nonidentical, distributions within chromatin. Our results suggest that H2A.Z-2 preferentially associates with H3 trimethylated at lysine 4 compared to H2A.Z-1. The phylogenetic analysis of the promoter regions of H2A.Z-1 and H2A.Z-2 indicate that they have evolved separately during vertebrate evolution. Conclusions Our biochemical, gene expression, and phylogenetic data suggest that the H2A.Z-1 and H2A.Z-2 variants function similarly yet they may have acquired a degree of functional independence.

  8. Long-Term Impact of the Dutch Colorectal Cancer Screening Program on Cancer Incidence and Mortality-Model-Based Exploration of the Serrated Pathway

    NARCIS (Netherlands)

    Greuter, Marjolein J. E.; Demirel, Erhan; Lew, Jie-Bin; Berkhof, Johannes; Xu, Xiang-Ming; Canfell, Karen; Dekker, Evelien; Meijer, Gerrit A.; Coupé, Veerle M. H.

    2016-01-01

    We aimed to predict the long-term colorectal cancer incidence, mortality, and colonoscopy demand of the recently implemented Dutch colorectal cancer screening program. The Adenoma and Serrated pathway to Colorectal Cancer model was set up to simulate the Dutch screening program consisting of

  9. EERE-SBIR technology transfer opportunity. H2 Safety Sensors for H2

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, Mariann R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-12-01

    The Office of Energy Efficiency and Renewable Energy’s Fuel Cell Technologies Office (FCTO) works in partnership with industry (including small businesses), academia, and DOE's national laboratories to establish fuel cell and hydrogen energy technologies as economically competitive contributors to U.S. transportation needs. The work that is envisioned between the SBIR/STTR grantee and Los Alamos National Laboratory would involve Technical Transfer of Los Alamos Intellectual Property (IP) on Thin-film Mixed Potential Sensor (U.S. Patent 7,264,700) and associated know-how for H2 sensor manufacturing and packaging.

  10. Photo-induced H2 production from a CH3OH-H2O solution at insulator surface

    National Research Council Canada - National Science Library

    Li, Rengui; Wang, Xiuli; Jin, Shaoqing; Zhou, Xin; Feng, Zhaochi; Li, Zheng; Shi, Jingying; Zhang, Qiao; Li, Can

    2015-01-01

    .... However, in this work, we found that a considerable amount of H2 can be generated from a CH3OH-H2O solution at a quartz surface using light with energy far outside the electronic absorbance range...

  11. Incidence of Dengue Hemorrhagic Fever Related to Annual Rainfall, Population Density, Larval Free Index and Prevention Program in Bandung 2008 to 2011

    Directory of Open Access Journals (Sweden)

    Anggia Karina

    2015-06-01

    Full Text Available Background: Dengue Hemorrhagic Fever (DHF remains one of health problems in all provinces in Indonesia including West Java. Bandung as the capital of West Java province has dengue prevalence that is above the average prevalence of all provinces. This study aimed to describe the pattern of dengue incidence rate, annual rainfall, population density, and larval free index as well as the implementation of prevention program in sub-districts with the highest incidence rate in Bandung between 2008 and 2011. Methods: A descriptive retrospective study was conducted in September 2012 using secondary data during the period of January 2008 to December 2011. The incidence rate was calculated based on DHF patients who live in Bandung. Data were analyzed using computer and Arc View 3.3. Pattern of incidence rate was characterized with red, yellow, and green region respectively. Results: The highest incidence rate of DHF occurred in 2009. Incidence increased in January to February and declined in the end of the year. Subdistricts with highest incidence had no highest annual rainfall and the population density below the average of population density in Bandung. The highest implementation of fogging program was not only performed in high incidence subdistricts but also in area with larval free index less than 95%. Larval free index in subdistricts with highest incidence were not all below 95%. Conclusions: Incidence of DHF increases after months of highly rainfall. The pattern of incidence rate in all subdistrict is dynamic and suspected do not related to annual rainfall, population density, high larva free index, and frequency of fogging.

  12. The Role of Endogenous H(2)S in Cardiovascular Physiology

    DEFF Research Database (Denmark)

    Skovgaard, Nini; Gouliaev, Anja; Aalling, Mathilde

    2011-01-01

    Recent research has shown that the endogenous gas hydrogen sulphide (H(2)S) is a signalling molecule of considerable biological potential and has been suggested to be involved in a vast number of physiological processes. In the vascular system, H(2)S is synthesized from cysteine by cystathionine......-γ-lyase (CSE) in smooth muscle cells (SMC) and 3-mercaptopyruvate sulfuresterase (3MST) and CSE in the endothelial cells. In pulmonary and systemic arteries, H(2)S induces relaxation and/or contraction dependent on the concentration of H(2)S, type of vessel and species. H(2)S relaxes SMC through a direct...

  13. Dynamic investigation of the diffusion absorption refrigeration system NH3-H2O-H2

    Directory of Open Access Journals (Sweden)

    Mohamed Izzedine Serge Adjibade

    2017-09-01

    Full Text Available This paper reports on a numerical and experimental study of a diffusion absorption refrigerator. The performance of the system is examined by computer simulation using MATLAB software and Engineering Equations Solver. A dynamic model is developed for each component of the system and solved numerically in order to predict the transient state of the diffusion absorption refrigeration. The experiment set included 0.04 m3 commercial absorption diffusion refrigerator working with the ammonia-water-hydrogen (NH3-H2O-H2 solution. The transient numerical results were validated with the experimental data. The investigations are focused on the dynamic profile of the temperature of each component. The results obtained agree with the experiment; the relative error between numerical and experimental models doesn’t exceed 15% for all temperatures of each component. The increase of the average ambient temperature from 23.04 °C to 32.56 °C causes an increase of the condensation temperature from 29.46 °C to 37.51 °C, and the best evaporation temperature obtained was 3 °C, with an ambient temperature of 23.04 °C. The results show that a minimum starting temperature of 152 °C and 63.8 W electric power are required to initiate the decrease of evaporation temperature.

  14. FLYING-WATER Renewables-H2-H2O TERRAFORMING: PERMANENT ETERNAL Drought(s)-Elimination FOREVER!!!

    Science.gov (United States)

    Wignall, J.; Lyons, Marv; Ertl, G.; Alefeld, Georg; Youdelis, W.; Radd, H.; Oertle, G.; Siegel, Edward

    2013-03-01

    ''H2O H2O everywhere; ne'er a drop to drink''[Coleridge(1798)] now: ''H2 H2 everywhere; STILL ne'er a drop to drink'': ONLY H2 (or methane CH4) can be FLYING-WATER(F-W) chemical-rain-in-pipelines Hindenberg-effect (H2-UP;H2O-DOWN): { ∖{}O/H2O{ ∖}} =[16]/[18] ∖sim 90{ ∖%} O already in air uphill; NO H2O pumping need! In global-warming driven H2O-starved glacial-melting world, rescue is possible ONLY by Siegel [ ∖underline {3rd Intl. Conf. Alt.-Energy }(1980)-vol.5/p.459!!!] Renewables-H2-H2O purposely flexible versatile agile customizable scaleable retrofitable integrated operating-system. Rosenfeld[Science 315,1396(3/9/2007)]-Biello [Sci.Am.(3/9 /2007)] crucial geomorphology which ONLY maximal-buoyancy H2 can exploit, to again make ''Mountains into Fountains'', ``upthrust rocks trapping the clouds to precipitate their rain/snow/H2O'': ''terraforming''(and ocean-rebasificaton!!!) ONLY VIA Siegel[APS March MTGS.:1960s-2000ss) DIFFUSIVE-MAGNETORESISTANCE (DMR) proprietary MAGNETIC-HYDROGEN-VALVE(MHV) ALL-IMPORTANT PRECLUDED RADIAL-diffusion, permitting ONLY AXIAL-H2-BALLISTIC-flow (``G.A''.''/DoE''/''Terrapower''/''Intellectual-Ventures''/ ''Gileland''/ ''Myhrvold''/''Gates'' ``ARCHIMEDES'') in ALREADY IN-ground dense BCC/ferritic-steels pipelines-network (NO new infrastructure) counters Tromp[Science 300,1740(2003)] dire warning of global-pandemics (cancers/ blindness/ famine)

  15. H2O2 Synthesis Induced by Irradiation of H2O with Energetic H(+) and Ar(+) Ions at Various Temperatures

    Science.gov (United States)

    Baragiola, R. A.; Loeffler, M. J.; Raut, U.; Vidal, R. A.; Carlson, R. W.

    2004-01-01

    The detection of H2O2 on Jupiter's icy satellite Europa by the Galileo NIMS instrument presented a strong evidence for the importance of radiation effects on icy surfaces. A few experiments have investigated whether solar flux of protons incident on Europa ice could cause a significant if any H2O2 production. These published results differ as to whether H2O2 can be formed by ions impacting water at temperatures near 80 K, which are appropriate to Europa. This discrepancy may be a result of the use of different incident ion energies, different vacuum conditions, or different ways of processing the data. The latter possibility comes about from the difficulty of identifying the 3.5 m peroxide OH band on the long wavelength wing of the much stronger water 3.1 m band. The problem is aggravated by using straight line baselines to represent the water OH band with a curvature, in the region of the peroxide band, that increases with temperature. To overcome this problem, we use polynomial baselines that provide good fits to the water band and its derivative.

  16. Role of Hearth Program with Undernutrition Incidence among Toddlers in Tangerang City

    Directory of Open Access Journals (Sweden)

    Gizella Gizella

    2016-08-01

    Kelompok yang rentan terhadap gizi kurang adalah balita. World Health Organization (WHO menyatakan kematian anak bawah lima tahun (balita akibat gizi kurang sebesar 54% pada tahun 2002. Di Indonesia, prevalensinya mengalami peningkatan dari 17,9% pada tahun 2010 menjadi 19,6% pada tahun 2013. Di Kota Tangerang, terdapat 1,43% balita yang mengalami gizi buruk pada tahun 2013. Penelitian ini bertujuan untuk membuktikan secara valid hubungan antara Program Pos Gizi yang meliputi perilaku pemberian makan, perilaku kebersihan balita, perilaku mencari pelayanan kesehatan dan perilaku pengasuhan balita dengan kejadian gizi kurang pada balita. Penelitian ini merupakan penelitian kuantitatif, potong lintang, menggunakan data primer serta dianalisis secara univariat, bivariat, dan multivariat selama satu bulan pada bulan September 2015. Sampel diambil secara total sampling sebanyak 60 balita yang mengalami gizi kurang di Kota Tangerang. Hasil menunjukkan bahwa dari 60 balita yang mengalami gizi kurang, sebanyak 12 balita (20% mengalami gizi sangat kurus dan sisanya sejumlah 48 balita (80% mengalami gizi kurus. Terdapat hubungan antara perilaku pemberian makan dan perilaku mencari pelayanan kesehatan dengan gizi kurang pada balita. Variabel perilaku pemberian makan merupakan faktor dominan yang memengaruhi gizi kurang pada balita dengan OR = 4,655 (CI = 1,052 – 20,6 setelah dikontrol oleh variabel perilaku mencari pelayanan kesehatan. Perbaikan pemberian makan dan pencarian pelayanan kesehatan diharapkan mampu memperbaiki dan menurunkan gizi kurang pada balita.

  17. H2O and CO coadsorption on Co (0001): The effect of intermolecular hydrogen bond

    Science.gov (United States)

    Jiawei, Wu; Chen, Jun; Guo, Qing; Su, Hai-Yan; Dai, Dongxu; Yang, Xueming

    2017-09-01

    The co-adsorption of CO and H2O on a Co(0001) surface at 100 K has been systematically studied using temperature programmed desorption (TPD) and density functional theory (DFT) calculations. While the TPD spectra of CO is almost not affected by the presence of H2O, the stabilization of H2O by co-adsorbed CO is found for the first time in a large coverage range (0.15 ML interaction between H2O molecules and the attractive interaction between H2O and CO molecules, respectively. With increasing the coverage of predosed CO, not only the position of the high temperature peak shifts toward higher temperature (by about 15 K), but the intensity is greatly strengthened until a maximum is achieved when θCO = 0.36 ML. DFT calculations suggest that the attractive interaction between H2O and CO on Co(0001) originates from the formation of intermolecular hydrogen bonds. This work not only provides insights into water gas shift reactions with H2O and CO as reactants, but opens new avenues for a volume of catalytic process of technological importance.

  18. Hydrogen polysulfide (H2S n ) signaling along with hydrogen sulfide (H2S) and nitric oxide (NO).

    Science.gov (United States)

    Kimura, Hideo

    2016-11-01

    Hydrogen sulfide (H2S) is a physiological mediator with various roles, including neuro-modulation, vascular tone regulation, and cytoprotection against ischemia-reperfusion injury, angiogenesis, and oxygen sensing. Hydrogen polysulfide (H2S n ), which possesses a higher number of sulfur atoms than H2S, recently emerged as a potential signaling molecule that regulates the activity of ion channels, a tumor suppressor, transcription factors, and protein kinases. Some of the previously reported effects of H2S are now attributed to the more potent H2S n . H2S n is produced by 3-mercaptopyruvate sulfurtransferase (3MST) from 3-mercaptopyruvate (3MP) and is generated by the chemical interaction of H2S with nitric oxide (NO). H2S n sulfhydrates (sulfurates) cysteine residues of target proteins and modifies their activity, whereas H2S sulfurates oxidized cysteine residues as well as reduces cysteine disulfide bonds. This review focuses on the recent progress made in studies concerning the production and physiological roles of H2S n and H2S.

  19. Changes in HIV incidence among people who inject drugs in Taiwan following introduction of a harm reduction program: a study of two cohorts.

    Directory of Open Access Journals (Sweden)

    Yen-Fang Huang

    2014-04-01

    Full Text Available Harm reduction strategies for combating HIV epidemics among people who inject drugs (PWID have been implemented in several countries. However, large-scale studies using sensitive measurements of HIV incidence and intervention exposures in defined cohorts are rare. The aim of this study was to determine the association between harm reduction programs and HIV incidence among PWID.The study included two populations. For 3,851 PWID who entered prison between 2004 and 2010 and tested HIV positive upon incarceration, we tested their sera using a BED HIV-1 capture enzyme immunoassay to estimate HIV incidence. Also, we enrolled in a prospective study a cohort of 4,357 individuals who were released from prison via an amnesty on July 16, 2007. We followed them with interviews at intervals of 6-12 mo and by linking several databases. A total of 2,473 participants who were HIV negative in January 2006 had interviews between then and 2010 to evaluate the association between use of harm reduction programs and HIV incidence. We used survival methods with attendance at methadone clinics as a time-varying covariate to measure the association with HIV incidence. We used a Poisson regression model and calculated the HIV incidence rate to evaluate the association between needle/syringe program use and HIV incidence. Among the population of PWID who were imprisoned, the implementation of comprehensive harm reduction programs and a lower mean community HIV viral load were associated with a reduced HIV incidence among PWID. The HIV incidence in this population of PWID decreased from 18.2% in 2005 to 0.3% in 2010. In an individual-level analysis of the amnesty cohort, attendance at methadone clinics was associated with a significantly lower HIV incidence (adjusted hazard ratio: 0.20, 95% CI: 0.06-0.67, and frequent users of needle/syringe program services had lower HIV incidence (0% in high NSP users, 0.5% in non NSP users. In addition, no HIV seroconversions were

  20. Detectability of H2-Ar and H2-Ne Dimers in Jovian Atmospheres

    Directory of Open Access Journals (Sweden)

    Young-Key Minn

    1997-12-01

    Full Text Available The detection of jovian hydrogen-hydrogen dimers through the clear telluric 2-micron window(Kim et al. 1995, Trafton et al. 1997 suggests possibility to detect noble gases in the form of dimer with hydrogen in jovian atmospheres. Since noble gases do not have spectral structures in the infrared, it has been difficult to derive their abundances in the atmospheres of jovian planets. If there is a significant component of noble gases other than helium in the jovian atmospheres. it might be detected through its dimer spectrum with hydrogen molecule. The relatively sharp spectral structures of hydrogen-argon and hydrogen-neon dimers compared with those of hydrogen-hydrogen dimers are useful for the detection, if an adequate signal-to-noise (S/N is obtained. If we use a large telescope, such as the Keck telescope, with a long exposure time (>24 hours, then H2-Ar spectral structure may be detected.

  1. The Histone H2B Monoubiquitination Regulatory Pathway Is Required for Differentiation of Multipotent Stem Cells

    DEFF Research Database (Denmark)

    Karpiuk, Oleksandra; Najafova, Zeynab; Kramer, Frank

    2012-01-01

    understood. We show that histone H2B monoubiquitination (H2Bub1) significantly increases during differentiation of human mesenchymal stem cells (hMSCs) and various lineage-committed precursor cells and in diverse organisms. Furthermore, the H2B ubiquitin ligase RNF40 is required for the induction......Extensive changes in posttranslational histone modifications accompany the rewiring of the transcriptional program during stem cell differentiation. However, the mechanisms controlling the changes in specific chromatin modifications and their function during differentiation remain only poorly...... during the transition from an inactive to an active chromatin conformation. Thus, these data indicate that H2Bub1 is required for maintaining multipotency of hMSCs and plays a central role in controlling stem cell differentiation....

  2. A potential energy surface for the process H2 + H2O yielding H + H + H2O - Ab initio calculations and analytical representation

    Science.gov (United States)

    Schwenke, David W.; Walch, Stephen P.; Taylor, Peter R.

    1991-01-01

    Extensive ab initio calculations on the ground state potential energy surface of H2 + H2O were performed using a large contracted Gaussian basis set and a high level of correlation treatment. An analytical representation of the potential energy surface was then obtained which reproduces the calculated energies with an overall root-mean-square error of only 0.64 mEh. The analytic representation explicitly includes all nine internal degrees of freedom and is also well behaved as the H2 dissociates; it thus can be used to study collision-induced dissociation or recombination of H2. The strategy used to minimize the number of energy calculations is discussed, as well as other advantages of the present method for determining the analytical representation.

  3. Electron scattering and ionization of H2O; OH, H2O2, HO2 radicals and (H2O)2 dimer

    Science.gov (United States)

    Joshipura, Kamalnayan N.; Pandya, Siddharth H.; Mason, Nigel J.

    2017-04-01

    Water, its dimer and their dissociative products (OH, H2O2, HO2) play an important role in several diverse processes including atmospheric chemistry, radiation induced damage within cellular systems and atmospheric plasmas used in industry. The interaction of electrons with these species is therefore an important collision process but since OH, H2O2 and HO2 are difficult to prepare as isolated experimental targets to date, electron scattering cross sections from such species are lacking in the literature. In this paper we report the results of a semi-empirical method to estimate such cross sections, benchmarking these cross sections against our knowledge of electron scattering from the water monomer. Calculations on HO2, H2O2 and (H2O2)2 are performed with improved Additivity Rules.

  4. Relaxation of H2O from its |04>- vibrational state in collisions with H2O, Ar, H2, N2, and O2

    Science.gov (United States)

    Barnes, Peter W.; Sims, Ian R.; Smith, Ian W. M.

    2004-03-01

    We report rate coefficients at 293 K for the collisional relaxation of H2O molecules from the highly excited |04>± vibrational states in collisions with H2O, Ar, H2, N2, and O2. In our experiments, the |04>- state is populated by direct absorption of radiation from a pulsed dye laser tuned to ˜719 nm. Evolution of the population in the (|04>±) levels is observed using the combination of a frequency-quadrupled Nd:YAG laser, which selectively photolyses H2O(|04>±), and a frequency-doubled dye laser, which observes the OH(v=0) produced by photodissociation via laser-induced fluorescence. The delay between the pulse from the pump laser and those from the photolysis and probe lasers was systematically varied to generate kinetic decays. The rate coefficients for relaxation of H2O(|04>±) obtained from these experiments, in units of cm3 molecule-1 s-1, are: k(H2O)=(4.1±1.2)×10-10, k(Ar)=(4.9±1.1)×10-12, k(H2)=(6.8±1.1)×10-12, k(N2)=(7.7±1.5)×10-12, k(O2)=(6.7±1.4)×10-12. The implications of these results for our previous reports of rate constants for the removal of H2O molecules in selected vibrational states by collisions with H atoms (P. W. Barnes et al., Faraday Discuss. Chem. Soc. 113, 167 (1999) and P. W. Barnes et al., J. Chem. Phys. 115, 4586 (2001).) are fully discussed.

  5. DFT Calculation of IR Absorption Spectra for PCE-nH2O, TCE-nH2O, DCE-nH2O, VC-nH2O for Small and Water-Dominated Molecular Clusters

    Science.gov (United States)

    2017-10-31

    202) 767-2601 Calculations are presented of vibrational absorption spectra for energy minimized structures of PCE-nH2O, TCE-nH2O, DCE-nH2O, and VC...2 Energy- Minimized Structures and Their IR Spectra………………. ………………………...….4 Conclusion...for calculation of absorption spectra is presented. Second, DFT calculations of energy- minimized structures and vibration resonance structure for

  6. Link state relationships under incident conditions : using a CTM-based linear programming dynamic traffic assignment model.

    Science.gov (United States)

    2010-03-01

    Urban transportation networks, consisting of numerous links and nodes, experience traffic incidents such as accidents and road : maintenance work. A typical consequence of incidents is congestion which results in long queues and causes high travel ti...

  7. Development of immunoaffinity chromatographic method for Ara h 2 isolation.

    Science.gov (United States)

    Wu, Zhihua; Zhang, Ying; Zhan, Shaode; Lian, Jun; Zhao, Ruifang; Li, Kun; Tong, Ping; Li, Xin; Yang, Anshu; Chen, Hongbing

    2017-03-01

    Ara h 2 is considered a major allergen in peanut. Due to the difficulty of separation, Ara h 2 had not been fully studied. Immunoaffinity chromatography (IAC) column can separate target protein with high selectivity, which made it possible to purify Ara h 2 from different samples. In this study, IAC method was developed to purify Ara h 2 and its effect was evaluated. By coupling polyclonal antibody (pAb) on CNBr-activated Sepharose 4B, the column for specific extraction was constructed. The coupling efficiency of the IAC column was higher than 90%, which made the capacity of column reached 0.56 mg per 0.15 g medium (dry weight). The recovery of Ara h 2 ranged from 93% to 100% for different concentrations of pure Ara h 2 solutions in 15 min. After using a column 10 times, about 88% of the column capacity remained. When applied to extract Ara h 2 from raw peanut protein extract and boiled peanut protein extract, the IAC column could recovery 94% and 88% target protein from the mixture. SDS-PAGE and Western blotting analysis confirmed the purified protein was Ara h 2, its purity reached about 90%. Significantly, the IAC column could capture dimer of Ara h 2, which made it feasible to prepared derivative of protein after processing. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Particulate filtration for sorbent-based H2 storage

    Science.gov (United States)

    van Hassel, Bart A.; Karra, Jagadeswara R.

    2016-01-01

    A method was developed for sizing the particulate filter that can be used inside a sorption-based onboard hydrogen storage system for light-duty vehicles. The method is based on a trade-off between the pressure drop across the particulate filter (during the fill of the H2 storage tank or during its discharge while driving) and the effect of this pressure drop on the usable amount of H2 gas from the H2 storage system. The permeability and filtration efficiency of the particulate filters (in the absence and presence of MOF-5 particulates) was quantified in this study, with an emphasis on meeting DOE's H2 purity requirements.

  9. Relative importance of H2 and H2S as energy sources for primary production in geothermal springs.

    Science.gov (United States)

    D'Imperio, Seth; Lehr, Corinne R; Oduro, Harry; Druschel, Greg; Kühl, Michael; McDermott, Timothy R

    2008-09-01

    Geothermal waters contain numerous potential electron donors capable of supporting chemolithotrophy-based primary production. Thermodynamic predictions of energy yields for specific electron donor and acceptor pairs in such systems are available, although direct assessments of these predictions are rare. This study assessed the relative importance of dissolved H(2) and H(2)S as energy sources for the support of chemolithotrophic metabolism in an acidic geothermal spring in Yellowstone National Park. H(2)S and H(2) concentration gradients were observed in the outflow channel, and vertical H(2)S and O(2) gradients were evident within the microbial mat. H(2)S levels and microbial consumption rates were approximately three orders of magnitude greater than those of H(2). Hydrogenobaculum-like organisms dominated the bacterial component of the microbial community, and isolates representing three distinct 16S rRNA gene phylotypes (phylotype = 100% identity) were isolated and characterized. Within a phylotype, O(2) requirements varied, as did energy source utilization: some isolates could grow only with H(2)S, some only with H(2), while others could utilize either as an energy source. These metabolic phenotypes were consistent with in situ geochemical conditions measured using aqueous chemical analysis and in-field measurements made by using gas chromatography and microelectrodes. Pure-culture experiments with an isolate that could utilize H(2)S and H(2) and that represented the dominant phylotype (70% of the PCR clones) showed that H(2)S and H(2) were used simultaneously, without evidence of induction or catabolite repression, and at relative rate differences comparable to those measured in ex situ field assays. Under in situ-relevant concentrations, growth of this isolate with H(2)S was better than that with H(2). The major conclusions drawn from this study are that phylogeny may not necessarily be reliable for predicting physiology and that H(2)S can dominate over H(2

  10. Improved photobiological H2 production in engineered green algal cells.

    Science.gov (United States)

    Kruse, Olaf; Rupprecht, Jens; Bader, Klaus-Peter; Thomas-Hall, Skye; Schenk, Peer Martin; Finazzi, Giovanni; Hankamer, Ben

    2005-10-07

    Oxygenic photosynthetic organisms use solar energy to split water (H2O) into protons (H+), electrons (e-), and oxygen. A select group of photosynthetic microorganisms, including the green alga Chlamydomonas reinhardtii, has evolved the additional ability to redirect the derived H+ and e- to drive hydrogen (H2) production via the chloroplast hydrogenases HydA1 and A2 (H2 ase). This process occurs under anaerobic conditions and provides a biological basis for solar-driven H2 production. However, its relatively poor yield is a major limitation for the economic viability of this process. To improve H2 production in Chlamydomonas, we have developed a new approach to increase H+ and e- supply to the hydrogenases. In a first step, mutants blocked in the state 1 transition were selected. These mutants are inhibited in cyclic e- transfer around photosystem I, eliminating possible competition for e- with H2ase. Selected strains were further screened for increased H2 production rates, leading to the isolation of Stm6. This strain has a modified respiratory metabolism, providing it with two additional important properties as follows: large starch reserves (i.e. enhanced substrate availability), and a low dissolved O2 concentration (40% of the wild type (WT)), resulting in reduced inhibition of H2ase activation. The H2 production rates of Stm6 were 5-13 times that of the control WT strain over a range of conditions (light intensity, culture time, +/- uncoupler). Typically, approximately 540 ml of H2 liter(-1) culture (up to 98% pure) were produced over a 10-14-day period at a maximal rate of 4 ml h(-1) (efficiency = approximately 5 times the WT). Stm6 therefore represents an important step toward the development of future solar-powered H2 production systems.

  11. Herschel-HIFI observations of H2O in high-mass star-forming regions : First results

    NARCIS (Netherlands)

    van der Tak, F.; Herpin, F.; Wyrowski, F.; Röllig, M.; Simon, R.; Ossenkopf, V.; Stutzki, J.

    2011-01-01

    This paper reviews the first results of observations of H2O line emission with Herschel-HIFI towards high-mass star-forming regions, obtained within the WISH guaranteed time program. The data reveal three kinds of gas-phase H2O: "cloud water" in cold tenuous foreground clouds, "envelope water" in

  12. Herschel-HIFI observations of H2O in high-mass star-forming regions: first results

    NARCIS (Netherlands)

    van der Tak, F.; Herpin, F.; Wyrowski, F.

    2011-01-01

    This paper reviews the first results of observations of H2O line emission with Herschel-HIFI towards high-mass star-forming regions, obtained within the WISH guaranteed time program. The data reveal three kinds of gas-phase H2O: "cloud water" in cold tenuous foreground clouds, "envelope water" in

  13. Molecular adsorption of H2 on small cationic nickel clusters

    NARCIS (Netherlands)

    Swart, I.|info:eu-repo/dai/nl/304837652; Gruene, P.; Fielicke, A.; Meijer, G.; Weckhuysen, B.M.|info:eu-repo/dai/nl/285484397; de Groot, F.M.F.|info:eu-repo/dai/nl/08747610X

    2008-01-01

    The adsorption of H2 on metal clusters is of interest in several fields, including metallurgy, catalysis and hydrogen storage. Hydrogen interacting with small Ni clusters is of special interest, as Ni is widely used as a hydrogenation catalyst. In general, reactions of H2 with extended Ni surfaces

  14. H2O Formation in C-rich AGB Winds

    NARCIS (Netherlands)

    Lombaert, R.; Decin, L.; Royer, P.; de Koter, A.; Cox, N.L.J.; De Ridder, J.; Khouri, T.; Agúndez, M.; Blommaert, J.A.D.L.; Gernicharo, J.; González-Alfonso, E.; Groenewegen, M.A.T.; Kerschbaum, F.; Neufeld, D.; Vandenbussche, B.; Waelkens, C.

    2015-01-01

    The Herschel detection of warm H2O vapor emission from C-rich winds of AGB stars challenges the current understanding of circumstellar chemistry. Two mechanisms have been invoked to explain warm H2O formation. In the first, penetration of UV interstellar radiation through a clumpy circumstellar

  15. Reining in H2O2 for Safe Signaling

    OpenAIRE

    Planson, Anne-Gaëlle; Delaunay‐Moisan, Agnès

    2010-01-01

    Mammalian cells use hydrogen peroxide (H(2)O(2)) not only to kill invading pathogens, but also as a signaling modulator. Woo et al. (2010) now show that the local inactivation of a H(2)O(2)-degrading enzyme ensures that the production of this oxidant is restricted to the signaling site.

  16. Dissociation path for H2 on Al(110)

    DEFF Research Database (Denmark)

    Hammer, Bjørk; Jacobsen, Karsten Wedel; Nørskov, Jens Kehlet

    1992-01-01

    The minimum energy path is calculated for an H2 molecule dissociating on an Al(110) surface within local density functional theory. The properties of the potential energy surface along the five H2 ionic coordinates perpendicular to the reaction path are also determined and shown to be essential f...

  17. Hormetic Effect of H2O2 in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Halyna M. Semchyshyn PhD

    2016-03-01

    Full Text Available In this study, we investigated the relationship between target of rapamycin (TOR and H2O2-induced hormetic response in the budding yeast Saccharomyces cerevisiae grown on glucose or fructose. In general, our data suggest that: (1 hydrogen peroxide (H2O2 induces hormesis in a TOR-dependent manner; (2 the H2O2-induced hormetic dose–response in yeast depends on the type of carbohydrate in growth medium; (3 the concentration-dependent effect of H2O2 on yeast colony growth positively correlates with the activity of glutathione reductase that suggests the enzyme involvement in the H2O2-induced hormetic response; and (4 both TOR1 and TOR2 are involved in the reciprocal regulation of the activity of glucose-6-phosphate dehydrogenase and glyoxalase 1.

  18. Allogeneic H-2 antigen expression is insufficient for tumor rejection.

    Science.gov (United States)

    Cole, G A; Cole, G A; Clements, V K; Garcia, E P; Ostrand-Rosenberg, S

    1987-12-01

    Murine A strain (KkDdLd) sarcoma I (SaI) tumor cells have been transfected with a cloned H-2Kb gene. The resulting clones (SKB clones) stably express high levels of a molecule that is serologically and biochemically indistinguishable from the H-2Kb antigen. SKB clones are not susceptible to cytotoxic T lymphocyte-mediated lysis by H-2Kb-specific bulk, cloned, or H-2Kb-restricted lymphocytic choriomeningitis virus-specific effectors. Survival times of A/J and B10.A mice challenged i.p. with the H-2Kb-expressing transfectants and the parental SaI cells are similar, suggesting that the presence of an allogeneic major histocompatibility complex class I antigen on the surface of this tumor line is insufficient for tumor rejection.

  19. H2, CO, and dust absorption through cold molecular clouds

    Science.gov (United States)

    Lacy, John H.; Sneden, Chris; Kim, Hwihyun; Jaffe, Daniel Thomas

    2017-06-01

    We have made observations with IGRINS on the Harlan J. Smith telescope at McDonald Observatory of near-infrared absorption by H2, CO, and dust toward stars behind molecular clouds, primarily the TMC. Prior to these observations, the abundance of H2 in molecular clouds, relative to the commonly used tracer CO, had only been measured toward a few embedded stars, which may be surrounded by atypical gas. The new observations provide a representative sample of these molecules in cold molecular gas. We find N(H2)/Av ~ 0.9e+21, N(CO)/Av ~ 1.6e+17, and H2/CO ~ 6000. The measured H2/CO ratio is consistent with that measured toward embedded stars in various molecular clouds, but half that derived from mm-wave observations of CO emission and star counts or other determinations of Av.

  20. Air Force NiH2 IPV storage testing

    Science.gov (United States)

    Smellie, Shawn; Hill, Carole A.

    1996-01-01

    USAF Phillips Laboratory Nickel Hydrogen IPV storage test, performed at the Naval Surface Warfare Center (NSWC) at Crane Indiana, is discussed. The storage tests is just one component of the USAF Phillips Laboratory Nickel Hydrogen IPV Test Program. The plan was to store cells for a defined period and cycle matching cells to determine the effect on cycle life. The storage period was completed in April 95 and the cycling cells have achieved five years of real time LEO cycling. The two main objectives of the storage test are: to investigate various methods on NiH2 cells by using two different manufacturers and two different storage methods or conditions, and to determine the effect of storage method on cycle performance and cycle life by using matching cells cycling at 25% depth of discharge. The comparisons between individual cycle performance as well as cycle life are also reported. During the test the following variables has been considered: constant potential, cell current, open circuit voltage, and temperature. The results of the test are also discussed using charts and tables.

  1. CO2 trapping in amorphous H2O ice: Relevance to polar mesospheric cloud particles

    Science.gov (United States)

    Mangan, T. P.; Frankland, V. L.; Plane, J. M. C.

    2015-05-01

    Polar mesospheric clouds form in the summer high latitude mesopause region and are primarily comprised of H2O ice, forming at temperatures below 150 K. Average summertime temperatures in the polar mesosphere (78°N) are approximately 125 K and can be driven lower than 100 K by gravity waves. Under these extreme temperature conditions and given the relative mesospheric concentrations of CO2 and H2O (~360 ppmv and ~10 ppmv, respectively) it has been hypothesised that CO2 molecules could become trapped within amorphous mesospheric ice particles, possibly making a significant contribution to the total condensed volume. Studies of CO2 trapping in co-deposited gas mixtures of increasing CO2:H2O ratio (deposited at 98 K) were analysed via temperature programmed desorption. CO2 trapping was found to be negligible when the H2O flux to the surface was reduced to 4.8×1013 molecules cm-2 s-1. This corresponds to an average of 0.4 H2O molecules depositing on an adsorbed CO2 molecule and thereby trapping it in amorphous ice. Extrapolating the experimental data to mesospheric conditions shows that a mesospheric temperature of 100 K would be required (at a maximum mesospheric H2O concentration of 10 ppmv) in order to trap CO2 in the ice particles. Given the rarity of this temperature being reached in the mesosphere, this process would be an unlikely occurrence.

  2. Polysulfides Link H2S to Protein Thiol Oxidation

    Science.gov (United States)

    Greiner, Romy; Pálinkás, Zoltán; Bäsell, Katrin; Becher, Dörte; Antelmann, Haike; Nagy, Péter

    2013-01-01

    Abstract Aims: Hydrogen sulfide (H2S) is suggested to act as a gaseous signaling molecule in a variety of physiological processes. Its molecular mechanism of action was proposed to involve protein S-sulfhydration, that is, conversion of cysteinyl thiolates (Cys-S−) to persulfides (Cys-S-S−). A central and unresolved question is how H2S—that is, a molecule with sulfur in its lowest possible oxidation state (−2)—can lead to oxidative thiol modifications. Results: Using the lipid phosphatase PTEN as a model protein, we find that the “H2S donor” sodium hydrosulfide (NaHS) leads to very rapid reversible oxidation of the enzyme in vitro. We identify polysulfides formed in NaHS solutions as the oxidizing species, and present evidence that sulfane sulfur is added to the active site cysteine. Polysulfide-mediated oxidation of PTEN was induced by all “H2S donors” tested, including sodium sulfide (Na2S), gaseous H2S, and morpholin-4-ium 4-methoxyphenyl(morpholino) phosphinodithioate (GYY4137). Moreover, we show that polysulfides formed in H2S solutions readily modify PTEN inside intact cells. Innovation: Our results shed light on the previously unresolved question of how H2S leads to protein thiol oxidation, and suggest that polysulfides formed in solutions of H2S mediate this process. Conclusion: This study suggests that the effects that have been attributed to H2S in previous reports may in fact have been mediated by polysulfides. It also supports the notion that sulfane sulfur rather than sulfide is the actual in vivo agent of H2S signaling. Antioxid. Redox Signal. 19, 1749–1765. PMID:23646934

  3. Energetics of CO2 and H2O adsorption on zinc oxide.

    Science.gov (United States)

    Gouvêa, Douglas; Ushakov, Sergey V; Navrotsky, Alexandra

    2014-08-05

    Adsorption of H2O and CO2 on zinc oxide surfaces was studied by gas adsorption calorimetry on nanocrystalline samples prepared by laser evaporation in oxygen to minimize surface impurities and degassed at 450 °C. Differential enthalpies of H2O and CO2 chemisorption are in the range -150 ±10 kJ/mol and -110 ±10 kJ/mol up to a coverage of 2 molecules per nm(2). Integral enthalpy of chemisorption for H2O is -96.8 ±2.5 kJ/mol at 5.6 H2O/nm(2) when enthalpy of water condensation is reached, and for CO2 is -96.6 ±2.5 kJ/mol at 2.6 CO2/nm(2) when adsorption ceases. These values are consistent with those reported for ZnO prepared by other methods after similar degas conditions. The similar energetics suggests possible competition of CO2 and H2O for binding to ZnO surfaces. Exposure of bulk and nanocrystalline ZnO with preadsorbed CO2 to water vapor results in partial displacement of CO2 by H2O. In contrast, temperature-programmed desorption (TPD) indicates that a small fraction of CO2 is retained on ZnO surfaces up to 800 °C, under conditions where all H2O is desorbed, with adsorption energies near -200 kJ/mol. Although molecular mechanisms of adsorption were not studied, the thermodynamic data are consistent with dissociative adsorption of H2O at low coverage and with several different modes of CO2 binding.

  4. A novel H2S/H2O2 fuel cell operating at the room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Sanli, Ayse Elif [Gazi University (Turkey)], email: aecsanli@gmail.com; Aytac, Aylin [Department of Chemistry, Faculty of Science, Gazi University, Teknikokullar (Turkey)], email: aytaca@gazi.edu.tr

    2011-07-01

    This study concerns the oxidation mechanism of hydrogen sulfide and a fuel cell; acidic peroxide is used as the oxidant and basic hydrogen sulfide is the fuel. A solid state H2S/H2O2 stable fuel cell was produced at room temperature. A cell potential of 0.85 V was reached; this is quite remarkable in comparison to the H2S/O2 fuel cell potential of 0.85 V obtained at 850-1000 degree celsius. The hydrogen sulfide goes through an oxidation reaction in the alkaline fuel cell (H2S/H2O2 fuel cell) which opens up the possibility of using the cheaper nickel as a catalyst. As a result, the fuel cell becomes a potentially low cost technology. A further benefit from using H2S as the alkaline liquid H2S/H2O2 fuel cell, is that sulfide ions are oxidized at the anode, releasing electrons. Sulfur produced reacts with the other sulfide ions and forms disulfide and polysulfide ions in basic electrolytes (such as Black Sea water).

  5. Expanded Capabilities for the Hydrogen Financial Analysis Scenario Tool (H2FAST)

    Energy Technology Data Exchange (ETDEWEB)

    Bush, Brian; Melaina, Marc; Penev, Michael

    2016-06-08

    This presentation describes how NREL expanded the capabilities for the Hydrogen Financial Analysis Scenario Tool (H2FAST) in FY16. It was presented at the U.S. Department of Energy Hydrogen and Fuel Cells Program 2016 Annual Merit Review and Peer Evaluation Meeting on June 8, 2016, in Washington, D.C.

  6. Control of H2S emissions using an ozone oxidation process: Preliminary results

    Science.gov (United States)

    Defaveri, D.; Ferrando, B.; Ferraiolo, G.

    1986-01-01

    The problem of eliminating industrial emission odors does not have a simple solution, and consequently has not been researched extensively. Therefore, an experimental research program regarding oxidation of H2S through ozone was undertaken to verify the applicable limits of the procedure and, in addition, was designed to supply a useful analytical means of rationalizing the design of reactors employed in the sector.

  7. INTERNATIONAL AGRICULTURAL LABORERS: PURÉPECHAS HIRED H2-A IN THE UNITED STATES

    Directory of Open Access Journals (Sweden)

    Casimiro Leco Tomás

    2014-01-01

    Full Text Available An analysis of the temporary workers program that are recruited by the H2-A type visas for agricultural workers, who leave the rural state of Michoacan, Mexico, particularly of indigenous Purepecha communities and what is their participation in contracts, cross-border connections and the impact on Mexico and the United States.

  8. Analysis of H2O in silicate glass using attenuated total reflectance (ATR) micro-FTIR spectroscopy

    Science.gov (United States)

    Lowenstern, Jacob B.; Pitcher, Bradley W.

    2013-01-01

    We present a calibration for attenuated total reflectance (ATR) micro-FTIR for analysis of H2O in hydrous glass. A Ge ATR accessory was used to measure evanescent wave absorption by H2O within hydrous rhyolite and other standards. Absorbance at 3450 cm−1 (representing total H2O or H2Ot) and 1630 cm−1 (molecular H2O or H2Om) showed high correlation with measured H2O in the glasses as determined by transmission FTIR spectroscopy and manometry. For rhyolite, wt%H2O=245(±9)×A3450-0.22(±0.03) and wt%H2Om=235(±11)×A1630-0.20(±0.03) where A3450 and A1630 represent the ATR absorption at the relevant infrared wavelengths. The calibration permits determination of volatiles in singly polished glass samples with spot size down to ~5 μm (for H2O-rich samples) and detection limits of ~0.1 wt% H2O. Basaltic, basaltic andesite and dacitic glasses of known H2O concentrations fall along a density-adjusted calibration, indicating that ATR is relatively insensitive to glass composition, at least for calc-alkaline glasses. The following equation allows quantification of H2O in silicate glasses that range in composition from basalt to rhyolite: wt%H2O=(ω×A3450/ρ)+b where ω = 550 ± 21, b = −0.19 ± 0.03, ρ = density, in g/cm3, and A3450 is the ATR absorbance at 3450 cm−1. The ATR micro-FTIR technique is less sensitive than transmission FTIR, but requires only a singly polished sample for quantitative results, thus minimizing time for sample preparation. Compared with specular reflectance, it is more sensitive and better suited for imaging of H2O variations in heterogeneous samples such as melt inclusions. One drawback is that the technique can damage fragile samples and we therefore recommend mounting of unknowns in epoxy prior to polishing. Our calibration should hold for any Ge ATR crystals with the same incident angle (31°). Use of a different crystal type or geometry would require measurement of several H2O-bearing standards to provide a crystal

  9. H2 separation using defect-free, inorganic composite membranes.

    Science.gov (United States)

    Yu, Miao; Funke, Hans H; Noble, Richard D; Falconer, John L

    2011-02-16

    Defect-free, microporous Al(2)O(3)/SAPO-34 zeolite composite membranes were prepared by coating hydrothermally grown zeolite membranes with microporous alumina using molecular layer deposition. These inorganic composite membranes are highly efficient for H(2) separation: their highest H(2)/N(2) mixture selectivity was 1040, in contrast with selectivities of 8 for SAPO-34 membranes. The composite membranes were selective for H(2) for temperatures up to at least 473 K and feed pressures up to at least 1.5 MPa; at 473 K and 1.5 MPa, the H(2)/N(2) separation selectivity was 750. The H(2)/CO(2) separation selectivity was lower than the H(2)/N(2) selectivity and decreased slightly with increasing pressure; the selectivity was 20 at 473 K and 1.5 MPa. The high H(2) selectivity resulted either because most of the pores in the Al(2)O(3) layer were slightly smaller than 0.36 nm (the kinetic diameter of N(2)) or because the Al(2)O(3) layer slightly narrowed the SAPO-34 pore entrance. These composite membranes may represent a new class of inorganic membranes for gas separation.

  10. Pyruvate Protects Pathogenic Spirochetes from H2O2 Killing

    Science.gov (United States)

    Troxell, Bryan; Zhang, Jun-Jie; Bourret, Travis J.; Zeng, Melody Yue; Blum, Janice; Gherardini, Frank; Hassan, Hosni M.; Yang, X. Frank

    2014-01-01

    Pathogenic spirochetes cause clinically relevant diseases in humans and animals, such as Lyme disease and leptospirosis. The causative agent of Lyme disease, Borrelia burgdorferi, and the causative agent of leptospirosis, Leptospria interrogans, encounter reactive oxygen species (ROS) during their enzootic cycles. This report demonstrated that physiologically relevant concentrations of pyruvate, a potent H2O2 scavenger, and provided passive protection to B. burgdorferi and L. interrogans against H2O2. When extracellular pyruvate was absent, both spirochetes were sensitive to a low dose of H2O2 (≈0.6 µM per h) generated by glucose oxidase (GOX). Despite encoding a functional catalase, L. interrogans was more sensitive than B. burgdorferi to H2O2 generated by GOX, which may be due to the inherent resistance of B. burgdorferi because of the virtual absence of intracellular iron. In B. burgdorferi, the nucleotide excision repair (NER) and the DNA mismatch repair (MMR) pathways were important for survival during H2O2 challenge since deletion of the uvrB or the mutS genes enhanced its sensitivity to H2O2 killing; however, the presence of pyruvate fully protected ΔuvrB and ΔmutS from H2O2 killing further demonstrating the importance of pyruvate in protection. These findings demonstrated that pyruvate, in addition to its classical role in central carbon metabolism, serves as an important H2O2 scavenger for pathogenic spirochetes. Furthermore, pyruvate reduced ROS generated by human neutrophils in response to the Toll-like receptor 2 (TLR2) agonist zymosan. In addition, pyruvate reduced neutrophil-derived ROS in response to B. burgdorferi, which also activates host expression through TLR2 signaling. Thus, pathogenic spirochetes may exploit the metabolite pyruvate, present in blood and tissues, to survive H2O2 generated by the host antibacterial response generated during infection. PMID:24392147

  11. H2 metabolism in the photosynthetic bacterium Rhodopseudomonas capsulata: production and utilization of H2 by resting cells.

    Science.gov (United States)

    Hillmer, P; Gest, H

    1977-02-01

    Photoproduction of H2 and activation of H2 for CO2 reduction (photoreduction) by Rhodopseudomonas capsulata are catalyzed by different enzyme systems. Formation of H2 from organic compounds is mediated by nitrogenase and is nto inhibited by an atmosphere of 99% H2. Cells grown photoheterotrophically on C4 dicarboxylic acids (with glutamate as N source) evolve H2 from the C4 acids and also from lactate and pyruvate; cells grown on C3 carbon sources, however, are inactive with the C4 acids, presumably because they lack inducible transport systems. Ammonia is known to inhibit N2 fixation by photosynthetic bacteria, and it also effectively prevents photoproduction of H2; these effects are due to inhibition and, in part, inactivation of nitrogenase. Biosynthesis of the latter, as measured by both H2 production and acetylene reduction assays, is markedly increased when cells are grown at high light intensity; synthesis of the photoreduction system, on the other hand, is not appreciably influenced by light intensity during photoheterotrophic growth. The photoreduction activity of cells grown on lactate + glutamate (which contain active nitrogenase) is greatly activated by NH4+, but this effect is not observed in cells grown with NH4+ as N source (nitrogenase repressed) or in a Nif- mutant that is unable to produce H2. Lactate, malate, and succinate, which are readily used as growth substrates by R. capsulata and are excellent H donors for photoproduction of H2, abolish photoreduction activity. The physiological significances of this phenomenon and of the reciprocal regulatory effects of NH4+ on H2 production and photoreduction are discussed.

  12. Broadening of spectral lines of CO2, N2O , H2CO, HCN, and H2S by pressure of gases dominant in planetary atmospheres (H2, He and CO2)

    Science.gov (United States)

    Samuels, Shanelle; Gordon, Iouli; Tan, Yan

    2018-01-01

    HITRAN1,2 is a compilation of spectroscopic parameters that a variety of computer codes use to predict and simulate the transmission and emission of light in planetary atmospheres. The goal of this project is to add to the potential of the HITRAN database towards the exploration of the planetary atmospheres by including parameters describing broadening of spectral lines by H2, CO2, and He. These spectroscopic data are very important for the study of the hydrogen and helium-rich atmospheres of gas giants as well as rocky planets with volcanic activities, including Venus and Mars, since their atmospheres are dominated by CO2. First step in this direction was accomplished by Wilzewski et al.3 where this was done for SO2, NH3, HF, HCl, OCS and C2H2. The molecules investigated in this work were CO2, N2O, H2CO, HCN and H2S. Line-broadening coefficients, line shifts and temperature-dependence exponents for transitions of these molecules perturbed by H2, CO2 and He have been assembled from available peer-reviewed experimental and theoretical sources. The data was evaluated and the database was populated with these data and their extrapolations/interpolations using semi-empirical models that were developed to this end.Acknowledgements: Financial support from NASA PDART grant NNX16AG51G and the Smithsonian Astrophysical Observatory Latino Initiative Program from the Latino Initiatives Pool, administered by the Smithsonian Latino Center is gratefully acknowledged.References: 1. HITRAN online http://hitran.org/2. Gordon, I.E., Rothman, L.S., Hill, C., Kochanov, R.V., Tan, Y., et al., 2017. The HITRAN2016 Molecular Spectroscopic Database. J. Quant. Spectrosc. Radiat. Transf. doi:10.1016/j.jqsrt.2017.06.0383. Wilzewski, J.S., Gordon, I.E., Kochanov, R. V., Hill, C., Rothman, L.S., 2016. H2, He, and CO2 line-broadening coefficients, pressure shifts and temperature-dependence exponents for the HITRAN database. Part 1: SO2, NH3, HF, HCl, OCS and C2H2. J. Quant. Spectrosc. Radiat

  13. Histamine H2 receptor - Involvement in gastric ulceration

    Science.gov (United States)

    Brown, P. A.; Vernikos-Danellis, J.; Brown, T. H.

    1976-01-01

    The involvement of the H1 and H2 receptors for histamine in the pathogenesis of gastric ulcers was investigated in rats. Metiamide, an H2 receptor antagonist, reliably reduced ulceration produced by stress alone or by a combination of stress and aspirin. In contrast, pyrilamine, which blocks only the H1 receptor, was without effect under these same conditions. The results support the hypothesis that histamine mediates both stress and stress plus aspirin induced ulceration by a mechanism involving the H2 receptor.

  14. The role of H2 antagonists in perennial allergic rhinitis.

    Science.gov (United States)

    Testa, B; Mesolella, C; Filippini, P; Campagnano, N; Testa, D; Mesolella, M; Sagnelli, E

    1993-09-01

    The biological effects of anti-H2 in allergic reactions are dose dependent: low doses enhance, and high doses significantly decrease the reaction of hypersensitivity. The administration of cimetidine H2 antagonist to 20 perennial allergic rhinitis patients brought about an abatement in the symptoms and a decrease in the total serum immunoglobulin E (IgE) levels in 72% of treated patients, but no variation was perceived in placebo-treated patients. These results strengthen the hypothesis of anti-H2-induced immunoregulatory effects and suggest a possible way of inhibiting IgE synthesis in vivo.

  15. A global potential energy surface for ArH2

    Science.gov (United States)

    Schwenke, David W.; Walch, Stephen P.; Taylor, Peter R.

    1993-01-01

    We describe a simple analytic representation of the ArH2 potential energy surface which well reproduces the results of extensive ab initio electronic structure calculations. The analytic representation smoothly interpolates between the dissociated H2 and strong bonding limits. In the fitting process, emphasis is made on accurately reproducing regions of the potential expected to be important for high temperature (ca. 3000 K) collision processes. Overall, the anisotropy and H2 bond length dependence of the analytic representation well reproduce the input data.

  16. Preparation of polyaniline/PbS core-shell nano/microcomposite and its application for photocatalytic H2 electrogeneration from H2O.

    Science.gov (United States)

    Rabia, Mohamed; Mohamed, H S H; Shaban, Mohamed; Taha, S

    2018-01-18

    Lead sulfide (PbS) and polyaniline (PANI) nano/microparticles were prepared. Then, PANI/PbS core-shell nano/microcomposites (I, II, and III) were prepared by oxidative polymerization of different aniline concentrations (0.01, 0.03, and 0.05 M), respectively, in the presence of 0.05 M PbS. FT-IR, XRD, SEM, HR-TEM, and UV-Vis analyses were carried out to characterize the samples. From the FT-IR data, there are redshifts in PbS and PANI nano/microparticles bands in comparison with PANI/PbS nano/microcomposites. The average crystallite sizes of PANI/PbS core-shell nano/microcomposites (I, II, and III) from XRD analyses were 46.5, 55, and 42.16 nm, respectively. From the optical analyses, nano/microcomposite (II) has the optimum optical properties with two band gaps values of 1.41 and 2.79 eV. Then, the nano/microcomposite (II) membrane electrode supported on ITO glass was prepared and applied on the photoelectrochemical (PEC) H2 generation from H2O. The characteristics current-voltage and current-time behaviors were measured at different wavelengths from 390 to 636 nm. Also, the incident photon-to-current conversion efficiency (IPCE) under monochromatic illumination condition was calculated. The optimum values for IPCE were 36.5 and 35.2% at 390 and 405 nm, respectively. Finally, a simple mechanism for PEC H2 generation from H2O using the nano/microcomposite (II) membrane electrode was mentioned.

  17. A comparison of ice VII formed in the H2O, NaCl-H2O, and CH3OH-H2O systems: Implications for H2O-rich planets

    Science.gov (United States)

    Frank, Mark R.; Aarestad, Elizabeth; Scott, Henry P.; Prakapenka, Vitali B.

    2013-02-01

    High-pressure H2O polymorphs, namely ice VI, ice VII, and ice X, are hypothesized to make up a considerable portion of the interiors of large icy satellites and select extra-solar planets. The incorporation of foreign ions or molecules into these high-pressure phases is possible through ocean-ice interaction, rock-ice interaction at depth, or processes that occurred during accretion. Recent research concerning the effects charged ions have on ice VII has shown that these ions notably affect the structure of ice VII (Frank et al., 2006; Klotz et al., 2009). This study was designed to determine the effects of a molecular impurity on ice VII and compare those effects to both pure H2O ice and ice with an ionic impurity. Ice samples were formed in this study via compression in a diamond anvil cell from either H2O, a 1.60 mol% NaCl aqueous solution, a 1.60 mol% CH3OH aqueous solution, or a 5.00 mol% CH3OH aqueous solution and were compressed up to 71 GPa at room temperature. Ice formed from pure H2O had no impurities whereas ices formed in the NaCl-H2O and CH3OH-H2O systems contained the impurities Na+ and Cl- and CH3OH, respectively. Pressure-volume relations were observed in situ by using synchrotron based X-ray diffraction and were used to determine the equations of state for ices formed in the H2O, NaCl-H2O and CH3OH-H2O systems. The data illustrate that ice VII formed from a NaCl-bearing aqueous solution exhibited a depressed volume when compared to that of H2O-only ice VII at any given pressure, whereas ice VII formed from CH3OH-bearing aqueous solutions showed an opposite trend, with an increase in volume relative to that of pure ice VII. The ices within planetary bodies will most likely have both ionic and molecular impurities and the trends outlined in this study can be used to improve density profiles of H2O-rich planetary bodies.

  18. Spatial H2O2 signaling specificity: H2O2 from chloroplasts and peroxisomes modulates the plant transcriptome differentially.

    Science.gov (United States)

    Sewelam, Nasser; Jaspert, Nils; Van Der Kelen, Katrien; Tognetti, Vanesa B; Schmitz, Jessica; Frerigmann, Henning; Stahl, Elia; Zeier, Jürgen; Van Breusegem, Frank; Maurino, Veronica G

    2014-07-01

    Hydrogen peroxide (H2O2) operates as a signaling molecule in eukaryotes, but the specificity of its signaling capacities remains largely unrevealed. Here, we analyzed whether a moderate production of H2O2 from two different plant cellular compartments has divergent effects on the plant transcriptome. Arabidopsis thaliana overexpressing glycolate oxidase in the chloroplast (Fahnenstich et al., 2008; Balazadeh et al., 2012) and plants deficient in peroxisomal catalase (Queval et al., 2007; Inzé et al., 2012) were grown under non-photorespiratory conditions and then transferred to photorespiratory conditions to foster the production of H2O2 in both organelles. We show that H2O2 originating in a specific organelle induces two types of responses: one that integrates signals independently from the subcellular site of H2O2 production and another that is dependent on the H2O2 production site. H2O2 produced in peroxisomes induces transcripts involved in protein repair responses, while H2O2 produced in chloroplasts induces early signaling responses, including transcription factors and biosynthetic genes involved in production of secondary signaling messengers. There is a significant bias towards the induction of genes involved in responses to wounding and pathogen attack by chloroplastic-produced H2O2, including indolic glucosinolates-, camalexin-, and stigmasterol-biosynthetic genes. These transcriptional responses were accompanied by the accumulation of 4-methoxy-indol-3-ylmethyl glucosinolate and stigmasterol. © The Author 2014. Published by the Molecular Plant Shanghai Editorial Office in association with Oxford University Press on behalf of CSPB and IPPE, SIBS, CAS.

  19. Electron Impact Ionization of SOx, NOx and H2 SO4 - The Aerosol Relevance

    Science.gov (United States)

    Vaishnav, B. G.; Patel, U. R.; Joshipura, K. N.; Pandya, S. H.

    2016-05-01

    This paper reports our theoretical studies on electron impact ionization of reactive molecules SOx, NOx (x = 1-3) and H2 SO4, at incident energies from threshold to 2000 eV. Motivation for this work derives from the relevance of these molecules in connection with atmospheric aerosols analysis through mass spectrometric studies and quantification of mass concentrations amongst the aerosol species. The ionization efficiency of a molecule is directly proportional to ionization cross section, which represents the efficiency on a per-molecule basis. Study of electron impact ionization cross sections of molecules, like H2 SO4, versus number of electrons in the molecule can lead to information about mass concentrations of aerosol species. We have employed in this work, the well-known spherical complex potential formalism (SCOP), which provides total elastic as well as inelastic cross sections, wherein the latter includes ionization cross sections. We have developed a method to extract ionization cross section from calculated inelastic cross section by introducing a ratio function, in a semi-empirical formalism known as CSP-ic method. For SOx and NOx targets single-centre scattering calculations are performed, while for H2 SO4, the additivity rule augmented with overlap or screening corrections, has been employed. The calculated cross sections are examined as functions of incident electron energy along with comparisons (theoretical or experimental) as available.

  20. The interstellar chemistry of H2C3O isomers.

    Science.gov (United States)

    Loison, Jean-Christophe; Agúndez, Marcelino; Marcelino, Núria; Wakelam, Valentine; Hickson, Kevin M; Cernicharo, José; Gerin, Maryvonne; Roueff, Evelyne; Guélin, Michel

    2016-03-11

    We present the detection of two H2C3O isomers, propynal and cyclopropenone, toward various starless cores and molecular clouds, together with upper limits for the third isomer propadienone. We review the processes controlling the abundances of H2C3O isomers in interstellar media showing that the reactions involved are gas-phase ones. We show that the abundances of these species are controlled by kinetic rather than thermodynamic effects.

  1. Molecular hydrogen (H2) emissions from gasoline and diesel vehicles.

    Science.gov (United States)

    Bond, S W; Alvarez, R; Vollmer, M K; Steinbacher, M; Weilenmann, M; Reimann, S

    2010-08-01

    This study assesses individual-vehicle molecular hydrogen (H2) emissions in exhaust gas from current gasoline and diesel vehicles measured on a chassis dynamometer. Absolute H2 emissions were found to be highest for motorcycles and scooters (141+/-38.6 mg km(-1)), approximately 5 times higher than for gasoline-powered automobiles (26.5+/-12.1 mg km(-1)). All diesel-powered vehicles emitted marginal amounts of H2 ( approximately 0.1 mg km(-1)). For automobiles, the highest emission factors were observed for sub-cycles subject to a cold-start (mean of 53.1+/-17.0 mg km(-1)). High speeds also caused elevated H2 emission factors for sub-cycles reaching at least 150 km h(-1) (mean of 40.4+/-7.1 mg km(-1)). We show that H2/CO ratios (mol mol(-1)) from gasoline-powered vehicles are variable (sub-cycle means of 0.44-5.69) and are typically higher (mean for automobiles 1.02, for 2-wheelers 0.59) than previous atmospheric ratios characteristic of traffic-influenced measurements. The lowest mean individual sub-cycle ratios, which correspond to high absolute emissions of both H2 and CO, were observed during cold starts (for automobiles 0.48, for 2-wheelers 0.44) and at high vehicle speeds (for automobiles 0.73, for 2-wheelers 0.45). This finding illustrates the importance of these conditions to observed H2/CO ratios in ambient air. Overall, 2-wheelers displayed lower H2/CO ratios (0.48-0.69) than those from gasoline-powered automobiles (0.75-3.18). This observation, along with the lower H2/CO ratios observed through studies without catalytic converters, suggests that less developed (e.g. 2-wheelers) and older vehicle technologies are largely responsible for the atmospheric H2/CO ratios reported in past literature. 2010 Elsevier B.V. All rights reserved.

  2. Microchannel Reactor System Design & Demonstration For On-Site H2O2 Production by Controlled H2/O2 Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Adeniyi Lawal

    2008-12-09

    We successfully demonstrated an innovative hydrogen peroxide (H2O2) production concept which involved the development of flame- and explosion-resistant microchannel reactor system for energy efficient, cost-saving, on-site H2O2 production. We designed, fabricated, evaluated, and optimized a laboratory-scale microchannel reactor system for controlled direct combination of H2 and O2 in all proportions including explosive regime, at a low pressure and a low temperature to produce about 1.5 wt% H2O2 as proposed. In the second phase of the program, as a prelude to full-scale commercialization, we demonstrated our H2O2 production approach by ‘numbering up’ the channels in a multi-channel microreactor-based pilot plant to produce 1 kg/h of H2O2 at 1.5 wt% as demanded by end-users of the developed technology. To our knowledge, we are the first group to accomplish this significant milestone. We identified the reaction pathways that comprise the process, and implemented rigorous mechanistic kinetic studies to obtain the kinetics of the three main dominant reactions. We are not aware of any such comprehensive kinetic studies for the direct combination process, either in a microreactor or any other reactor system. We showed that the mass transfer parameter in our microreactor system is several orders of magnitude higher than what obtains in the macroreactor, attesting to the superior performance of microreactor. A one-dimensional reactor model incorporating the kinetics information enabled us to clarify certain important aspects of the chemistry of the direct combination process as detailed in section 5 of this report. Also, through mathematical modeling and simulation using sophisticated and robust commercial software packages, we were able to elucidate the hydrodynamics of the complex multiphase flows that take place in the microchannel. In conjunction with the kinetics information, we were able to validate the experimental data. If fully implemented across the whole

  3. Design of a MT-DBD reactor for H2S control

    Science.gov (United States)

    Cao, Xu; Zhao, Weixuan; Zhang, Renxi; Hou, Huiqi; Chen, Shanping; Zhang, Ruina

    2017-04-01

    This study aimed to discuss the removal of hydrogen sulfide (H2S) with non-thermal plasma produced by a multilayer tubular dielectric barrier discharge reactor, which is useful in the field of plasma environmental applications. We explored the influence of various factors upon H2S removal efficiency ({η }{{{H}}2{{S}}}) and energy yield (Ey), such as specific energy density (SED), initial concentration, gas flow velocity and the reactor configuration. The study showed that we can achieve {η }{{{H}}2{{S}}} of 91% and the best Ey of 3100 mg kWh-1 when we set the SED, gas flow velocity, initial H2S concentration and layers of quartz tubes at 33.2 J l-1, 8.0 m s-1, 30 mg m-3 and five layers, correspondingly. The average rate constant for the decomposition of hydrogen sulfide was 0.206 g m-3 s-1. In addition, we also presented the optimized working conditions, by-product analysis and decomposition mechanism. Supported by programs of Research on the Technology and Equipment of Gaseous Pollutant Removal from the Emission of Household Garbage (15DZ12055904) and Jointly Decomposition of Odorous Compounds by Dielectric Combined with Excimer Ultraviolet Emission (21577023).

  4. Chemistry of energetically activated cumulenes - from allene (H2CCCH2) to hexapentaene (H2CCCCCCH2).

    Science.gov (United States)

    Gu, Xibin; Kaiser, Ralf I; Mebel, Alexander M

    2008-02-22

    During the last decade, experimental and theoretical studies on the unimolecular decomposition of cumulenes (H(2)C(n)H(2)) from propadiene (H(2)CCCH(2)) to hexapentaene (H(2)CCCCCCH(2)) have received considerable attention due to the importance of these carbon-bearing molecules in combustion flames, chemical vapor deposition processes, atmospheric chemistry, and the chemistry of the interstellar medium. Cumulenes and their substituted counterparts also have significant technical potential as elements for molecular machines (nanomechanics), molecular wires (nano-electronics), nonlinear optics, and molecular sensors. In this review, we present a systematic overview of the stability, formation, and unimolecular decomposition of chemically, photo-chemically, and thermally activated small to medium-sized cumulenes in extreme environments. By concentrating on reactions under gas phase thermal conditions (pyrolysis) and on molecular beam experiments conducted under single-collision conditions (crossed beam and photodissociation studies), a comprehensive picture on the unimolecular decomposition dynamics of cumulenes transpires.

  5. Kinetics of oxidation of H2 and reduction of H2O in Ni-YSZ based solid oxide cells

    DEFF Research Database (Denmark)

    Ebbesen, Sune Dalgaard; Mogensen, Mogens Bjerg

    2012-01-01

    Reduction of H2O and oxidation of H2 was studied in a Ni-YSZ electrode supported Solid Oxide Cells produced at DTU Energy conversion (former Risø DTU). Polarisation (i-V) and electrochemical impedance spectroscopic characterisation show that the kinetics for reduction of H 2O is slower compared...... to oxidation of H2. The kinetic differences cannot be explained by the reaction mechanisms which are similar in the two cases but are rather an effect of the thermodynamics. The preliminary analysis performed in this study show that the slow kinetic for reduction is partly related to the endothermic nature...... of the reaction, cooling the active electrode, thereby leading to slower kinetics at low current densities. Likewise, the increased kinetic for oxidation was found to be related to the exothermic nature of the reaction, heating the active electrode, and thereby leading to faster kinetics. At higher current...

  6. Destruction and Sequestration of H2O on Mars

    Science.gov (United States)

    Clark, Benton

    2016-07-01

    The availability of water in biologically useable form on any planet is a quintessential resource, even if the planet is in a zone habitable with temperature regimes required for growth of organisms (above -18 °C). Mars and most other planetary objects in the solar system do not have sufficient liquid water at their surfaces that photosynthesis or chemolithoautotrophic metabolism could occur. Given clear evidence of hydrous mineral alteration and geomorphological constructs requiring abundant supplies of liquid water in the past, the question arises whether this H2O only became trapped physically as ice, or whether there could be other, more or less accessible reservoirs that it has evolved into. Salts containing S or Cl appear to be ubiquitous on Mars, having been measured in soils by all six Mars landed missions, and detected in additional areas by orbital investigations. Volcanoes emit gaseous H2S, S, SO2, HCl and Cl2. A variety of evidence indicates the geochemical fate of these gases is to be transformed into sulfates, chlorides, chlorates and perchlorates. Depending on the gas, the net reaction causes the destruction of between one and up to eight molecules of H2O per atom of S or Cl (although hydrogen atoms are also released, they are lost relatively rapidly to atmospheric escape). Furthermore, the salt minerals formed often incorporate H2O into their crystalline structures, and can result in the sequestration of up to yet another six (sometimes, more) molecules of H2O. In addition, if the salts are microcrystalline or amorphous, they are potent adsorbents for H2O. In certain cases, they are even deliquescent under martian conditions. Finally, the high solubility of the vast majority of these salts (with notable exception of CaSO4) can result in dense brines with low water activity, aH, as well as cations which can be inimical to microbial metabolism, effectively "poisoning the well." The original geologic materials on Mars, igneous rocks, also provide some

  7. Evaluation of multivalent H2 influenza pandemic vaccines in mice.

    Science.gov (United States)

    Lenny, Brian J; Sonnberg, Stephanie; Danner, Angela F; Friedman, Kimberly; Webby, Richard J; Webster, Robert G; Jones, Jeremy C

    2017-03-07

    Subtype H2 Influenza A viruses were the cause of a severe pandemic in the winter of 1957. However, this subtype no longer circulates in humans and is no longer included in seasonal vaccines. As a result, individuals under 50years of age are immunologically naïve. H2 viruses persist in aquatic birds, which were a contributing source for the 1957 pandemic, and have also been isolated from swine. Reintroduction of the H2 via zoonotic transmission has been identified as a pandemic risk, so pre-pandemic planning should include preparation and testing of vaccine candidates against this subtype. We evaluated the immunogenicity of two inactivated, whole virus influenza vaccines (IVV) in mice: a monovalent IVV containing human pandemic virus A/Singapore/1/1957 (H2N2), and a multivalent IVV containing human A/Singapore/1/1957, avian A/Duck/HongKong/319/1978 (H2N2), and swine A/Swine/Missouri/2124514/2006 (H2N3) viruses. While both vaccines induced protective immunity compared to naïve animals, the multivalent formulation was advantageous over the monovalent in terms of level and breadth of serological responses, neutralization of infectious virus, and reduction of clinical disease and respiratory tissue replication in mice. Therefore, multivalent pandemic H2 vaccines containing diverse viruses from animal reservoirs, are a potential option to improve the immune responses in a pre-pandemic scenario where antigenic identity cannot be predicted. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  8. Calculation of intermolecular potentials for H2sbnd H2 and H2sbnd O2 dimers ab initio and prediction of second virial coefficients

    Science.gov (United States)

    Pham Van, Tat; Deiters, Ulrich K.

    2015-08-01

    The intermolecular interaction potentials of the dimers H2sbnd H2 and H2sbnd O2 were calculated from quantum mechanics, using coupled-cluster theory CCSD(T) and correlation-consistent basis sets aug-cc-pVmZ (m = 2, 3); the results were extrapolated to the basis set limit aug-cc-pV23Z. The interaction energies were corrected for the basis set superposition error with the counterpoise scheme. For comparison also Møller-Plesset perturbation theory (at levels 2-4) with the basis sets aug-cc-pVTZ were considered, but the results proved inferior. The quantum mechanical results were used to construct analytical pair potential functions. From these functions the second virial coefficients of hydrogen and the cross virial coefficients of the hydrogen-oxygen system were obtained by integration; in both cases corrections for quantum effects were included. The results agree well with experimental data, if available, or with empirical correlations.

  9. A Prospective Study of the Incidence of Juvenile-Onset Recurrent Respiratory Papillomatosis After Implementation of a National HPV Vaccination Program.

    Science.gov (United States)

    Novakovic, Daniel; Cheng, Alan T L; Zurynski, Yvonne; Booy, Robert; Walker, Paul J; Berkowitz, Robert; Harrison, Henley; Black, Robert; Perry, Christopher; Vijayasekaran, Shyan; Wabnitz, David; Burns, Hannah; Tabrizi, Sepehr N; Garland, Suzanne M; Elliott, Elizabeth; Brotherton, Julia M L

    2017-11-09

    Recurrent respiratory papillomatosis is a rare but morbid disease caused by human papillomavirus (HPV) types 6 and 11. Infection is preventable through HPV vaccination. Following an extensive quadrivalent HPV vaccination program (females 12-26 years in 2007-2009) in Australia, we established a method to monitor incidence and demographics of juvenile-onset recurrent respiratory papillomatosis (JORRP) cases. The Australian Paediatric Surveillance Unit undertakes surveillance of rare pediatric diseases by contacting practitioners monthly. We enrolled pediatric otorhinolaryngologists and offered HPV typing. We report findings for 5 years to end 2016. The average annual incidence rate was 0.07 per 100000. The largest number of cases was reported in the first year, with decreasing annual frequency thereafter. Rates declined from 0.16 per 100000 in 2012 to 0.02 per 100000 in 2016 (P = .034). Among the 15 incident cases (60% male), no mothers were vaccinated prepregnancy, 20% had maternal history of genital warts, and 60% were first born; 13/15 were born vaginally. Genotyped cases were HPV-6 (n = 4) or HPV-11 (n = 3). To our knowledge, this is the first report internationally documenting decline in JORRP incidence in children following a quadrivalent HPV vaccination program.

  10. Incidence of apoptotic bodies in membrana granulosa of the patients participating in an in vitro fertilization program.

    Science.gov (United States)

    Nakahara, K; Saito, H; Saito, T; Ito, M; Ohta, N; Sakai, N; Tezuka, N; Hiroi, M; Watanabe, H

    1997-02-01

    To investigate the incidence of apoptotic bodies in mural granulosa cell masses and cumulus cell masses. Nonrandomized, prospective study. Department of Obstetrics and Gynecology, Yamagata University School of Medicine, Yamagata, Japan. One hundred twenty-nine normally ovulating women underwent ovulation induction for IVF-ET with GnRH analogue (GnRH-a) and gonadotropins. Patients underwent follicle aspiration after the administration of hCG. The nuclei of recovered granulosa cells were examined by fluorescence microscopy and the incidence of apoptotic bodies was tabulated. The incidence of apoptotic bodies was significantly higher in mural granulosa cell masses than in cumulus cell masses in the entire group of 129 patients. Both incidence of apoptotic bodies of mural granulosa cell masses and cumulus cell masses were significantly higher in patients with less than six follicular oocytes compared with patients with six or more oocytes. Nonpregnant patients showed significantly higher incidence of apoptotic bodies in mural granulosa cell masses compared with pregnant patients. These results indicate that mural granulosa cell masses and cumulus cell masses may have different functions in follicular maturation. The incidence of apoptotic bodies in mural granulosa cell masses can be used as an indicator of success of IVF.

  11. Enhanced selectivity towards O2 and H2 dissociation on ultrathin Cu films on Ru(0001).

    Science.gov (United States)

    Minniti, M; Farías, D; Perna, P; Miranda, R

    2012-08-21

    The reactivity of Cu monolayer (ML) and bilayer films grown on Ru(0001) towards O(2) and H(2) has been investigated. O(2) initial sticking coefficients were determined using the King and Wells method in the incident energy range 40-450 meV, and compared to the corresponding values measured on clean Ru(0001) and Cu(111) surfaces. A relative large O(2) sticking coefficient (~0.5-0.8) was measured for 1 ML Cu and even 2 ML Cu/Ru(0001). At low incident energies, this is one order of magnitude larger than the value observed on Cu(111). In contrast, the corresponding reactivity to H(2) was near zero on both Cu monolayer and bilayer films, for incident energies up to 175 meV. Water adsorption on 2 ML Cu/Ru(0001) was found to behave quite differently than on the Ru(0001) and Cu(111) surfaces. Our study shows that Cu/Ru(0001) is a highly selective system, which presents a quite different chemical reactivity towards different species in the same range of collision energies.

  12. Electrochemical, H2O2-Boosted Catalytic Oxidation System

    Science.gov (United States)

    Akse, James R.; Thompson, John O.; Schussel, Leonard J.

    2004-01-01

    An improved water-sterilizing aqueous-phase catalytic oxidation system (APCOS) is based partly on the electrochemical generation of hydrogen peroxide (H2O2). This H2O2-boosted system offers significant improvements over prior dissolved-oxygen water-sterilizing systems in the way in which it increases oxidation capabilities, supplies H2O2 when needed, reduces the total organic carbon (TOC) content of treated water to a low level, consumes less energy than prior systems do, reduces the risk of contamination, and costs less to operate. This system was developed as a variant of part of an improved waste-management subsystem of the life-support system of a spacecraft. Going beyond its original intended purpose, it offers the advantage of being able to produce H2O2 on demand for surface sterilization and/or decontamination: this is a major advantage inasmuch as the benign byproducts of this H2O2 system, unlike those of systems that utilize other chemical sterilants, place no additional burden of containment control on other spacecraft air- or water-reclamation systems.

  13. H∞ /H2 model reduction through dilated linear matrix inequalities

    DEFF Research Database (Denmark)

    Adegas, Fabiano Daher; Stoustrup, Jakob

    2012-01-01

    This paper presents sufficient dilated linear matrix inequalities (LMI) conditions to the $H_{infty}$ and $H_{2}$ model reduction problem. A special structure of the auxiliary (slack) variables allows the original model of order $n$ to be reduced to an order $r=n/s$ where $n,r,s in field{N}$. Arb......This paper presents sufficient dilated linear matrix inequalities (LMI) conditions to the $H_{infty}$ and $H_{2}$ model reduction problem. A special structure of the auxiliary (slack) variables allows the original model of order $n$ to be reduced to an order $r=n/s$ where $n,r,s in field...... not satisfactorily approximates the original system, an iterative algorithm based on dilated LMIs is proposed to significantly improve the approximation bound. The effectiveness of the method is accessed by numerical experiments. The method is also applied to the $H_2$ order reduction of a flexible wind turbine...

  14. Data-Driven Controller Design The H2 Approach

    CERN Document Server

    Sanfelice Bazanella, Alexandre; Eckhard, Diego

    2012-01-01

    Data-driven methodologies have recently emerged as an important paradigm alternative to model-based controller design and several such methodologies are formulated as an H2 performance optimization. This book presents a comprehensive theoretical treatment of the H2 approach to data-driven control design. The fundamental properties implied by the H2 problem formulation are analyzed in detail, so that common features to all solutions are identified. Direct methods (VRFT) and iterative methods (IFT, DFT, CbT) are put under a common theoretical framework. The choice of the reference model, the experimental conditions, the optimization method to be used, and several other designer’s choices are crucial to the quality of the final outcome, and firm guidelines for all these choices are derived from the theoretical analysis presented. The practical application of the concepts in the book is illustrated with a large number of practical designs performed for different classes of processes: thermal, fluid processing a...

  15. A Global PLASIMO Model for H2O Chemistry

    Science.gov (United States)

    Tadayon Mousavi, Samaneh; Koelman, Peter; Graef, Wouter; Mihailova, Diana; van Dijk, Jan; EPG/ Applied Physics/ Eindhoven University of Technology Team; Plasma Matters B. V. Team

    2016-09-01

    Global warming is one of the critical contemporary problems for mankind. Transformation of CO2 into fuels, like CH4, that are transportable with the current infrastructure seems a promising idea to solve this threatening issue. The final aim of this research is to produce CH4 by using microwave plasma in CO2 -H2 O mixture and follow-up catalytic processes. In this contribution we present a global model for H2 O chemistry that is based on the PLASIMO plasma modeling toolkit. The time variation of the electron energy and the species' densities are calculated based on the source and loss terms in plasma due to chemical reactions. The short simulation times of such models allow an efficient assessment and chemical reduction of the H2O chemistry, which is required for full spatially resolved simulations.

  16. Physicochemical characteristics of anaerobic H2-producing granular sludge.

    Science.gov (United States)

    Li, Wen-Wei; Yu, Han-Qing

    2011-09-01

    Granule-based biological H2 production processes are gaining great popularity in recent years. An efficient and stable operating of such systems relies heavily on the performance of the H2-producing granules (HPGs), which possess many unique properties compared with floc sludge and methanogenic granules. Hence, a full understanding of the sludge characteristics is essential. Especially, the physicochemical properties of HPGs may provide useful information for effective evaluation of system status. This review offers a systematical introduction of the physicochemical properties of HPGs, including size, morphology, settling velocity, permeability, rheology, surface charge, hydrophobicity and extracellular polymeric substances (EPS). We also analyze the relationships between these physicochemical factors and the system performance, and discuss the remaining challenges and future implications for sludge characterization and process monitoring. This work may facilitate a better understanding of granule-based biological H2 production processes and offer a basis for timely process monitoring and manipulation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. H2O2_COD_EPA; MEC_acclimation

    Science.gov (United States)

    H2O2_COD_EPA: Measurements of hydrogen peroxide and COD concentrations for water samples from the MEC reactors.MEC_acclimation: raw data for current and voltage of the anode in the MEC reactor.This dataset is associated with the following publication:Sim, J., J. An, E. Elbeshbishy, R. Hodon, and H. Lee. Characterization and optimization of cathodic conditions for H2O2 synthesis in microbial electrochemical cells. Bioresource Technology. Elsevier Online, New York, NY, USA, 195: 31-36, (2015).

  18. Reduction of nitrobenzene with H2 using a microbial consortium.

    Science.gov (United States)

    Cao, Hong-Bin; Li, Yu-Ping; Zhang, Gui-Feng; Zhang, Yi

    2004-02-01

    Proof of concept was obtained that nitrobenzene can be reduced to aniline by a mixed reductive microbial culture using H2 as the sole electron donor source. In a continuous-flow anaerobic bioreactor, both pH and temperature affected nitrobenzene reduction with optima of pH 6.5-6.8 and 30 degrees C. The efficiency of nitrobenzene degradation increased with H2 up to 10% (v/v). An increase in sulfate concentration decreased the removal rate of nitrobenzene.

  19. Proses Absorpsi Gas H2S Menggunakan Metildietanolamin

    OpenAIRE

    W, Ririen; Bahruddin, Bahruddin; Zultiniar, Zultiniar

    2014-01-01

    H2S in the oil and gas industry is undesirable because it can lead to corrosion of pipes and equipment production. The purpose of this research is to study the effect of distance and the injection of absorbent flow rate. Absorption processes carried out continuously with free variables absorbent flow rate of 40 ml/min, 60 ml/min, 80 ml/min and 100 ml/min, with a distance of injection of 110 m, 140 m , and 170 m. The results of absorption H2S was measured by using a gas detector tube sys...

  20. Single Molecular Junction Study on H2 O@C60 : H2 O is "Electrostatically Isolated".

    Science.gov (United States)

    Kaneko, Satoshi; Hashikawa, Yoshifumi; Fujii, Shintaro; Murata, Yasujiro; Kiguchi, Manabu

    2017-05-19

    A water molecule exhibits characteristic properties on the basis of hydrogen bonding. In the past decade, single water molecules placed in non-hydrogen-bonding environments have attracted growing attention. To reveal the fundamental properties of a single water molecule, endohedral fullerene H2 O@C60 is an ideal and suitable model. We examined the electronic properties of H2 O@C60 by performing single-molecule measurements. The conductance of a single molecular junction based on H2 O@C60 was found to be comparable to that of empty C60 . The observed values were remarkably higher than those obtained for conventional molecular junctions due to the effective hybridization of the π-conjugated system to the metal electrode. Additionally, the results undoubtedly exclude the possibility of electrostatic contact of entrapped H2 O with the carbon wall of C60 . We finally concluded that H2 O entrapped inside a C60 cage can be regarded as an electrostatically isolated molecule. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. The H2 + CO ↔ H2CO Reaction: Rate Constants and Relevance to Hot and Dense Astrophysical Media

    Science.gov (United States)

    Vichietti, R. M.; Spada, R. F. K.; da Silva, A. B. F.; Machado, F. B. C.; Haiduke, R. L. A.

    2016-07-01

    A theoretical thermochemical and kinetic investigation of the thermal H2 + CO ↔ H2CO reaction was performed for a temperature range from 200 to 4000 K. Geometries and vibrational frequencies of reactants, product, and transition state (TS) were obtained at CCSD/cc-pVxZ (x = T and Q) levels and scaling factors were employed to consider anharmonicity effects on vibrational frequencies, zero-point energies, and thermal corrections provided by these methodologies. Enthalpies Gibbs energies, and rate constants for this reaction were determined by including a complete basis set extrapolation correction for the electronic properties calculated at CCSD(T)/cc-pVyZ (y = Q and 5) levels. Our study indicates that enthalpy changes for this reaction are highly dependent on temperature. Moreover, forward and reverse (high-pressure limit) rate constants were obtained from variational TS theory with quantum tunneling corrections. Thus, modified Arrhenius’ equations were fitted by means of the best forward and reverse rate constant values, which provide very reliable estimates for these quantities within the temperature range between 700 and 4000 K. To our knowledge, this is the first kinetic study done for the forward H2 + CO \\to H2CO process in a wide temperature range. Finally, these results can be used to explain the formaldehyde abundance in hot and dense interstellar media, possibly providing data about the physical conditions associated with H2CO masers close to massive star-forming regions.

  2. Physical chemistry of the H2SO4/HNO3/H2O system - Implications for polar stratospheric clouds

    Science.gov (United States)

    Molina, M. J.; Zhang, R.; Wooldridge, P. J.; Mcmahon, J. R.; Kim, J. E.; Chang, H. Y.; Beyer, K. D.

    1993-01-01

    Polar stratospheric clouds (PSCs) play a key role in stratospheric ozone depletion. Surface-catalyzed reactions on PSC particles generate chlorine compounds that photolyze readily to yield chlorine radicals, which in turn destroy ozone very efficiently. The most prevalent PSCs form at temperatures several degrees above the ice frost point and are believed to consist of HNO3 hydrates; however, their formation mechanism is unclear. Results of laboratory experiments are presented which indicate that the background stratospheric H2SO4/H2O aerosols provide an essential link in this mechanism: These liquid aerosols absorb significant amounts of HNO3 vapor, leading most likely to the crystallization of nitric acid trihydrate (NAT). The frozen particles then grow to form PSCs by condensation of additional amounts of HNO3 and H2O vapor. Furthermore, reaction probability measurements reveal that the chlorine radical precursors are formed readily at polar stratospheric temperatures not just on NAT and ice crystals, but also on liquid H2SO4 solutions and on solid H2SO4 hydrates. These results imply that the chlorine activation efficiency of the aerosol particles increases rapidly as the temperature approaches the ice frost point regardless of the phase or composition of the particles.

  3. A Critical Review of Models of the H-2/H2O/Ni/SZ Electrode Kinetics

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Høgh, Jens Valdemar Thorvald; Hansen, Karin Vels

    2007-01-01

    sets, which do not fit the model. We have inspected some models in the literature, and problems (e.g. no quantitative model has explained the large variation in reported values of apparent activation energy of the electrode kinetics) as well as strengths of the models are discussed. We point out......Various models of the H-2/H2O/Ni/SZ (SZ = stabilized zirconia) electrode kinetics have been presented in the literature in order to explain the reported experimental data. However, there has been a strong tendency of using a limited set of data to "verify" a given model, disregarding other data...... experimental findings that a useful model must be able to explain such as difference in sensitivity to poisoning by H2S due to differences in the detailed composition of the SZ and large change in apparent activation energy by change in cermet preparation. Finally, we will point out some elements, which seem...

  4. Solar kerosene from H2O and CO2

    Science.gov (United States)

    Furler, P.; Marxer, D.; Scheffe, J.; Reinalda, D.; Geerlings, H.; Falter, C.; Batteiger, V.; Sizmann, A.; Steinfeld, A.

    2017-06-01

    The entire production chain for renewable kerosene obtained directly from sunlight, H2O, and CO2 is experimentally demonstrated. The key component of the production process is a high-temperature solar reactor containing a reticulated porous ceramic (RPC) structure made of ceria, which enables the splitting of H2O and CO2 via a 2-step thermochemical redox cycle. In the 1st reduction step, ceria is endo-thermally reduced using concentrated solar radiation as the energy source of process heat. In the 2nd oxidation step, nonstoichiometric ceria reacts with H2O and CO2 to form H2 and CO - syngas - which is finally converted into kerosene by the Fischer-Tropsch process. The RPC featured dual-scale porosity for enhanced heat and mass transfer: mm-size pores for volumetric radiation absorption during the reduction step and μm-size pores within its struts for fast kinetics during the oxidation step. We report on the engineering design of the solar reactor and the experimental demonstration of over 290 consecutive redox cycles for producing high-quality syngas suitable for the processing of liquid hydrocarbon fuels.

  5. Intermolecular Interactions in Ternary Glycerol–Sample–H2O

    DEFF Research Database (Denmark)

    Westh, Peter; Rasmussen, Erik Lumby; Koga, Yoshikata

    2011-01-01

    We studied the intermolecular interactions in ternary glycerol (Gly)–sample (S)–H2O systems at 25 °C. By measuring the excess partial molar enthalpy of Gly, HGlyEHEGly, we evaluated the Gly–Gly enthalpic interaction, HGly-GlyEHEGly--Gly, in the presence of various samples (S). For S, tert...

  6. Selective effects of H2O2 on cyanobacterial photosynthesis

    NARCIS (Netherlands)

    Drabkova, M.; Matthijs, H.C.P.; Admiraal, W.; Marsalek, B.

    2007-01-01

    Abstract: The sensitivity of phytoplankton species for hydrogen peroxide (H2O2) was analyzed by pulse amplitude modulated (PAM) fluorometry. The inhibition of photosynthesis was more severe in five tested cyanobacterial species than in three green algal species and one diatom species. Hence the

  7. Robust H2 performance for sampled-data systems

    DEFF Research Database (Denmark)

    Rank, Mike Lind

    1997-01-01

    Robust H2 performance conditions under structured uncertainty, analogous to well known methods for H∞ performance, have recently emerged in both discrete and continuous-time. This paper considers the extension into uncertain sampled-data systems, taking into account inter-sample behavior. Convex...

  8. PEM Electrolysis H2A Production Case Study Documentation

    Energy Technology Data Exchange (ETDEWEB)

    James, Brian [Strategic Analysis Inc. (SA), Arlington, Virginia; Colella, Whitney [Strategic Analysis Inc. (SA), Arlington, Virginia; Moton, Jennie [Strategic Analysis Inc. (SA), Arlington, Virginia; Saur, G. [Strategic Analysis Inc. (SA), Arlington, Virginia; Ramsden, T. [Strategic Analysis Inc. (SA), Arlington, Virginia

    2013-12-31

    This report documents the development of four DOE Hydrogen Analysis (H2A) case studies for polymer electrolyte membrane (PEM) electrolysis. The four cases characterize PEM electrolyzer technology for two hydrogen production plant sizes (Forecourt and Central) and for two technology development time horizons (Current and Future).

  9. Ultrafast Librational Relaxation of H2O in Liquid Water

    DEFF Research Database (Denmark)

    Petersen, Jakob; Møller, Klaus Braagaard; Rey, Rossend

    2013-01-01

    The ultrafast librational (hindered rotational) relaxation of a rotationally excited H2O molecule in pure liquid water is investigated by means of classical nonequilibrium molecular dynamics simulations and a power and work analysis. This analysis allows the mechanism of the energy transfer from...

  10. Inelastic scattering in metal-H-2-metal junctions

    DEFF Research Database (Denmark)

    Kristensen, I. S.; Paulsson, Magnus; Thygesen, Kristian Sommer

    2009-01-01

    of longitudinal vibrations of the H-2 molecule. In the case of Pt electrodes, the transverse vibrations can mediate transport through otherwise nontransmitting Pt d channels leading to an increase in the differential conductance even though the hydrogen junction is characterized predominately by a single almost...

  11. Atmospheric photochemical loss of H and H2 from formaldehyde

    DEFF Research Database (Denmark)

    Simonsen, Jens Bæk; Rusteika, Nerijus; Johnson, Matthew Stanley

    2008-01-01

    We have performed ab initio calculations to examine the potential energy along the normal modes of ground-state HCHO and along the reaction coordinates for loss of H2 and atomic hydrogen, respectively. This exploration showed that there are no specific features that will lead to reaction on the e...

  12. ISO Spectroscopy of H2 in Star Forming Regions

    NARCIS (Netherlands)

    Van den Ancker, M. E.; Wesselius, P. R.; Tielens, A. G. G. M.

    2000-01-01

    Abstract: We have studied molecular hydrogen emission in a sample of 21 YSOs using spectra obtained with the Infrared Space Observatory (ISO). H2 emission was detected in 12 sources and can be explained as arising in either a shock, caused by the interaction of an outflow from an embedded YSO with

  13. submitter Thermodynamics of the formation of sulfuric acid dimers in the binary (H2SO4–H2O) and ternary (H2SO4–H2O–NH3) system

    CERN Document Server

    Kürten, A; Rondo, L; Bianchi, F; Duplissy, J; Jokinen, T; Junninen, H; Sarnela, N; Schobesberger, S; Simon, M; Sipilä, M; Almeida, J; Amorim, A; Dommen, J; Donahue, N M; Dunne, E M; Flagan, R C; Franchin, A; Kirkby, J; Kupc, A; Makhmutov, V; Petäjä, T; Praplan, A P; Riccobono, F; Steiner, G; Tomé, A; Tsagkogeorgas, G; Wagner, P E; Wimmer, D; Baltensperger, U; Kulmala, M; Worsnop, D R; Curtius, J

    2015-01-01

    Sulfuric acid is an important gas influencing atmospheric new particle formation (NPF). Both the binary $(H_2SO_4–H_2O)$ system and the ternary system involving ammonia $(H_2SO_4–H_2O–NH_3)$ may be important in the free troposphere. An essential step in the nucleation of aerosol particles from gas-phase precursors is the formation of a dimer, so an understanding of the thermodynamics of dimer formation over a wide range of atmospheric conditions is essential to describe NPF. We have used the CLOUD chamber to conduct nucleation experiments for these systems at temperatures from 208 to 248 K. Neutral monomer and dimer concentrations of sulfuric acid were measured using a chemical ionization mass spectrometer (CIMS). From these measurements, dimer evaporation rates in the binary system were derived for temperatures of 208 and 223 K. We compare these results to literature data from a previous study that was conducted at higher temperatures but is in good agreement with the present study. For the ternary sys...

  14. Dynamics of H2 on Ti/Al(100) surfaces

    NARCIS (Netherlands)

    Chen, Jian-Cheng

    2011-01-01

    What is the catalytic role played by titanium in the hydrogen storage material NaAlH4? This thesis aims at unraveling the dynamics of an elementary reaction: H2 dissociation on Ti/Al(100) surfaces. Although this reaction is not the rate limiting step in the hydrogen storage of NaAlH4, it is an

  15. Hydrogen Financial Analysis Scenario Tool (H2FAST); NREL (National Renewable Energy Laboratory)

    Energy Technology Data Exchange (ETDEWEB)

    Melaina, Marc

    2015-04-21

    This presentation describes the Hydrogen Financial Analysis Scenario Tool, H2FAST, and provides an overview of each of the three H2FAST formats: the H2FAST web tool, the H2FAST Excel spreadsheet, and the H2FAST Business Case Scenario (BCS) tool. Examples are presented to illustrate the types of questions that H2FAST can help answer.

  16. Emergency medical services response to active shooter incidents: provider comfort level and attitudes before and after participation in a focused response training program.

    Science.gov (United States)

    Jones, Jerrilyn; Kue, Ricky; Mitchell, Patricia; Eblan, Gary; Dyer, K Sophia

    2014-08-01

    Emergency Medical Services (EMS) routinely stage in a secure area in response to active shooter incidents until the scene is declared safe by law enforcement. Due to the time-sensitive nature of injuries at these incidents, some EMS systems have adopted response tactics utilizing law enforcement protection to expedite life-saving medical care. Describe EMS provider perceptions of preparedness, adequacy of training, and general attitudes toward active shooter incident response after completing a tactical awareness training program. An unmatched, anonymous, closed-format survey utilizing a five-point Likert scale was distributed to participating EMS providers before and after a focused training session on joint EMS/police active shooter rescue team response. Descriptive statistics were used to compare survey results. Secondary analysis of responses based on prior military or tactical medicine training was performed using a chi-squared analysis. Two hundred fifty-six providers participated with 88% (225/256) pretraining and 88% (224/256) post-training surveys completed. Post-training, provider agreement that they felt adequately prepared to respond to an active shooter incident changed from 41% (92/225) to 89% (199/224), while agreement they felt adequately trained to provide medical care during an active shooter incident changed from 36% (82/225) to 87% (194/224). Post-training provider agreement that they should never enter a building with an active shooter changed from 73% (165/225) to 61% (137/224). Among the pretraining surveys, significantly more providers without prior military or tactical experience agreed they should never enter a building with an active shooter until the scene was declared safe (78% vs 50%, P = .002), while significantly more providers with prior experience felt both adequately trained to provide medical care in an active shooter environment (56% vs 31%, P = .007) and comfortable working jointly with law enforcement within a building if a

  17. Vibrational investigations of CO2-H2O, CO2-(H2O)2, and (CO2)2-H2O complexes isolated in solid neon.

    Science.gov (United States)

    Soulard, P; Tremblay, B

    2015-12-14

    The van der Waals complex of H2O with CO2 has attracted considerable theoretical interest as a typical example of a weak binding complex with a dissociation energy less than 3 kcal/mol. Up to now, experimental vibrational data are sparse. We have studied by FTIR the complexes involving CO2 and water molecules in solid neon. Many new absorption bands close to the well known monomers fundamentals give evidence for at least three (CO2)n-(H2O)m complexes, noted n:m. Concentration effects combined with a detailed vibrational analysis allow for the identification of sixteen, twelve, and five transitions for the 1:1, 1:2, and 2:1 complexes, respectively. Careful examination of the far infrared spectral region allows the assignment of several 1:1 and 1:2 intermolecular modes, confirmed by the observation of combinations of intra + intermolecular transitions, and anharmonic coupling constants have been derived. Our results demonstrate the high sensibility of the solid neon isolation to investigate the hydrogen-bonded complexes in contrast with the gas phase experiments for which two quanta transitions cannot be easily observed.

  18. Don't overlook disease management programs for low-incidence, high-cost diseases to improve your bottom line.

    Science.gov (United States)

    Bruce, D; Dickmeyer, J

    2001-01-01

    Comprehensive coordinated care management for low-incident, high-cost diseases, like chronic renal failure, can provide a great opportunity for health plans to add immediate and significant profit to their bottom line. The resultant benefits of improved operations, improved clinical outcomes and increased patient satisfaction add further incentive for health plans to take action to implement outsourced disease management for this condition.

  19. H2 emission from non-stationary magnetized bow shocks

    Science.gov (United States)

    Tram, L. N.; Lesaffre, P.; Cabrit, S.; Gusdorf, A.; Nhung, P. T.

    2018-01-01

    When a fast moving star or a protostellar jet hits an interstellar cloud, the surrounding gas gets heated and illuminated: a bow shock is born that delineates the wake of the impact. In such a process, the new molecules that are formed and excited in the gas phase become accessible to observations. In this paper, we revisit models of H2 emission in these bow shocks. We approximate the bow shock by a statistical distribution of planar shocks computed with a magnetized shock model. We improve on previous works by considering arbitrary bow shapes, a finite irradiation field and by including the age effect of non-stationary C-type shocks on the excitation diagram and line profiles of H2. We also examine the dependence of the line profiles on the shock velocity and on the viewing angle: we suggest that spectrally resolved observations may greatly help to probe the dynamics inside the bow shock. For reasonable bow shapes, our analysis shows that low-velocity shocks largely contribute to H2 excitation diagram. This can result in an observational bias towards low velocities when planar shocks are used to interpret H2 emission from an unresolved bow. We also report a large magnetization bias when the velocity of the planar model is set independently. Our 3D models reproduce excitation diagrams in BHR 71 and Orion bow shocks better than previous 1D models. Our 3D model is also able to reproduce the shape and width of the broad H2 1-0S(1) line profile in an Orion bow shock (Brand et al. 1989).

  20. Tricyclic sesquiterpene copaene prevents H2O2-induced neurotoxicity

    Directory of Open Access Journals (Sweden)

    Hasan Turkez

    2014-02-01

    Full Text Available Aim: Copaene (COP, a tricyclic sesquiterpene, is present in several essential oils of medicinal and aromatic plants and has antioxidant and anticarcinogenic features. But, very little information is known about the effects of COP on oxidative stress induced neurotoxicity. Method: We used hydrogen peroxide (H2O2 exposure for 6 h to model oxidative stress. Therefore, this experimental design allowed us to explore the neuroprotective potential of COP in H2O2-induced toxicity in rat cerebral cortex cell cultures for the first time. For this purpose, methyl thiazolyl tetrazolium (MTT and lactate dehydrogenase (LDH release assays were carried out to evaluate cytotoxicity. Total antioxidant capacity (TAC and total oxidative stress (TOS parameters were used to evaluate oxidative changes. In addition to determining of 8-hydroxy-2-deoxyguanosine (8-OH-dG levels, the single cell gel electrophoresis (SCGE or comet assay was also performed for measuring the resistance of neuronal DNA to H2O2-induced challenge. Result: The results of this study showed that survival and TAC levels of the cells decreased, while TOS, 8-OH-dG levels and the mean values of the total scores of cells showing DNA damage increased in the H2O2 alone treated cultures. But pre-treatment of COP suppressed the cytotoxicity, genotoxicity and oxidative stress which were increased by H2O2. Conclusion: It is proposed that COP as a natural product with an antioxidant capacity in mitigating oxidative injuries in the field of neurodegenerative diseases. [J Intercult Ethnopharmacol 2014; 3(1.000: 21-28

  1. Pilot-scale UV/H2O2 study for emerging organic contaminants decomposition.

    Science.gov (United States)

    Chu, Xiaona; Xiao, Yan; Hu, Jiangyong; Quek, Elaine; Xie, Rongjin; Pang, Thomas; Xing, Yongjie

    2016-03-01

    Human behaviors including consumption of drugs and use of personal care products, climate change, increased international travel, and the advent of water reclamation for direct potable use have led to the introduction of significant amounts of emerging organic contaminants into the aqueous environment. In addition, the lower detection limits associated with improved scientific methods of chemical analysis have resulted in a recent increase in documented incidences of these contaminants which previously were not routinely monitored in water. Such contaminants may cause known or suspected adverse ecological and/or human health effects at very low concentrations. Conventional drinking water treatment processes may not effectively remove these organic contaminants. Advanced oxidation process (AOP) is a promising treatment process for the removal of most of these emerging organic contaminants, and has been accepted worldwide as a suitable treatment process. In this study, different groups of emerging contaminants were studied for decomposition efficiency using pilot-scale UV/H2O2 oxidation setup, including EDCs, PPCPs, taste and odor (T&O), and perfluorinated compounds. Results found that MP UV/H2O2 AOP was efficient in removing all the selected contaminants except perfluorinated compounds. Study of the kinetics of the process showed that both light absorption and quantum yield of each compound affected the decomposition performance. Analysis of water quality parameters of the treated water indicated that the outcome of both UV photolysis and UV/H2O2 processes can be affected by changes in the feed water quality.

  2. Isotopic Effects on Stereodynamics of the C+ + H2 → CH+ + H Reaction

    Science.gov (United States)

    Guo, Lu; Yang, Yun-Fan; Fan, Xiao-Xing; Ma, Feng-Cai; Li, Yong-Qing

    2017-05-01

    The effects of isotope substitution on stereodynamic properties for the reactions {C}++{H}2/{H D}/{H T}\\to {{C H}}++H/D/T have been studied applying a quasi classical trajectory method occurring on the new ground state {{C H}}2+ potential energy surface [J. Chem. Phys. 142 (2015) 124302]. In the center of mass coordinates applying the quasi classical trajectory method to investigate the orientation and the alignment of the product molecule. Differential cross section and three angle distribution functions P(θr), P(ϕr), P( {θ }r,{φ }r ) on the potential energy surface that fixed the collision energy with a value is 40 kcal/mol have been studied. The isotope effect becomes more and more important with the reagent molecules H 2 changing into HD and HT. P({θ }r,{φ }r) as the joint probability density function of both polar angles θ r and ϕ r , which can illustrate more detailed dynamics information. The isotope effect is obvious influence on the properties of stereodynamics in the reactions of {C}++{H}2/{H D}/{H T}\\to {{C H}}++H/D/T. Supported by the National Natural Science Foundation of China under Grant Nos. 11474141, 11274149, 11544015, the Program for Liaoning Excellent Talents in University under Grant No. LJQ2015040, and the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry (2014-1685)

  3. Evaluation of the incidence of dental caries in patients with Down syndrome after their insertion in a preventive program

    OpenAIRE

    Aline Rogéria Freire de Castilho; Sara Nader Marta

    2010-01-01

    O objetivo deste trabalho foi verificar a incidência de cárie dentária por meio dos índices CPO-D, CPO-S, ceo-d e ceo-s em indivíduos com síndrome de Down regularmente matriculados em um programa preventivo. Foram examinados 24 indivíduos com síndrome de Down de ambos os sexos, com idade entre um e 48 anos. A prevalência (situação experimental inicial) e a incidência (situação experimental final) de cárie dentária foram verificadas utilizando-se os índices CPO-D, CPO-S, ceo-d e ceo-s iniciais...

  4. Vibrational kinetics of electronically excited states in H2 discharges

    Science.gov (United States)

    Colonna, Gianpiero; Pietanza, Lucia D.; D'Ammando, Giuliano; Celiberto, Roberto; Capitelli, Mario; Laricchiuta, Annarita

    2017-11-01

    The evolution of atmospheric pressure hydrogen plasma under the action of repetitively ns electrical pulse has been investigated using a 0D state-to-state kinetic model that self-consistently couples the master equation of heavy particles and the Boltzmann equation for free electrons. The kinetic model includes, together with atomic hydrogen states and the vibrational kinetics of H2 ground state, vibrational levels of singlet states, accounting for the collisional quenching, having a relevant role because of the high pressure. The mechanisms of excitations, radiative decay and collisional quenching involving the excited H2 states and the corresponding cross sections, integrated over the non-equilibrium electron energy distribution function (EEDF) to obtain kinetic rates, are discussed in the light of the kinetic simulation results, i.e. the time evolution during the pulse of the plasma composition, of the EEDF and of the vibrational distributions of ground and singlet excited states.

  5. Co3(PO42·4H2O

    Directory of Open Access Journals (Sweden)

    Yang Kim

    2008-10-01

    Full Text Available Single crystals of Co3(PO42·4H2O, tricobalt(II bis[orthophosphate(V] tetrahydrate, were obtained under hydrothermal conditions. The title compound is isotypic with its zinc analogue Zn3(PO42·4H2O (mineral name hopeite and contains two independent Co2+ cations. One Co2+ cation exhibits a slightly distorted tetrahedral coordination, while the second, located on a mirror plane, has a distorted octahedral coordination environment. The tetrahedrally coordinated Co2+ is bonded to four O atoms of four PO43− anions, whereas the six-coordinate Co2+ is cis-bonded to two phosphate groups and to four O atoms of four water molecules (two of which are located on mirror planes, forming a framework structure. In addition, hydrogen bonds of the type O—H...O are present throughout the crystal structure.

  6. Mixed H2/H∞ control of flexible structures

    Directory of Open Access Journals (Sweden)

    D. P. De Farias

    2001-01-01

    Full Text Available This paper addresses the design of full order linear dynamic output feedback controllers for flexible structures. Unstructured H∞ uncertainty models are introduced for systems in modal coordinates and in reduced order form. Then a controller is designed in order to minimize a given H2 performance function while keeping the maximum supported H∞ perturbation below some appropriate level. To solve this problem we develop an algorithm able to provide local optimal solutions to optimization problems with convex constraints and non-convex but differentiable objective functions. A controller design procedure based on a trade-off curve is proposed and a simple example is solved, providing a comparison between the proposed method and the usual minimization of an upper bound H2 to the norm. The method is applied to two different flexible structure theoretical models and the properties of the resulting controllers are shown in several simulations.

  7. Mixed H 2 / H ∞ control of flexible structures

    Directory of Open Access Journals (Sweden)

    De Farias D. P.

    2000-01-01

    Full Text Available This paper addresses the design of full order linear dynamic output feedback controllers for flexible structures. Unstructured H ∞ uncertainty models are introduced for systems in modal coordinates and in reduced order form. Then a controller is designed in order to minimize a given H 2 performance function while keeping the maximum supported H ∞ perturbation below some appropriate level. To solve this problem we develop an algorithm able to provide local optimal solutions to optimization problems with convex constraints and non-convex but differentiable objective functions. A controller design procedure based on a trade-off curve is proposed and a simple example is solved, providing a comparison between the proposed method and the usual minimization of an upper bound H 2 to the norm. The method is applied to two different flexible structure theoretical models and the properties of the resulting controllers are shown in several simulations.

  8. Ab initio Potential Energy Surface for H-H2

    Science.gov (United States)

    Partridge, Harry; Bauschlicher, Charles W., Jr.; Stallcop, James R.; Levin, Eugene

    1993-01-01

    Ab initio calculations employing large basis sets are performed to determine an accurate potential energy surface for H-H2 interactions for a broad range of separation distances. At large distances, the spherically averaged potential determined from the calculated energies agrees well with the corresponding results determined from dispersion coefficients; the van der Waals well depth is predicted to be 75 +/- (mu)E(sub h). Large basis sets have also been applied to reexamine the accuracy of theoretical repulsive potential energy surfaces. Multipolar expansions of the computed H-H2 potential energy surface are reported for four internuclear separation distances (1.2, 1.401, 1.449, and 1.7a(sub 0) of the hydrogen molecule. The differential elastic scattering cross section calculated from the present results is compared with the measurements from a crossed beam experiment.

  9. Synthesis, DFT calculations of structure, vibrational and thermal decomposition studies of the metal complex Pb[Mn(C3H2O4)2(H2O)2].

    Science.gov (United States)

    Gil, Diego M; Carbonio, Raúl E; Gómez, María Inés

    2015-04-15

    The metallo-organic complex Pb[Mn(C3H2O4)2(H2O)2] was synthesized and characterized by IR and Raman spectroscopy and powder X-ray diffraction methods. The cell parameters for the complex were determined from powder X-ray diffraction using the autoindexing program TREOR, and refined by the Le Bail method with the Fullprof program. A hexagonal unit cell was determined with a=b=13.8366(7)Å, c=9.1454(1)Å, γ=120°. The DFT calculated geometry of the complex anion [Mn(C3H2O4)2(H2O)2](2-) is very close to the experimental data reported for similar systems. The IR and Raman spectra and the thermal analysis of the complex indicate that only one type of water molecules is present in the structure. The thermal decomposition of Pb[Mn(C3H2O4)2(H2O)2] at 700 °C in air produces PbO and Pb2MnO4 as final products. The crystal structure of the mixed oxide is very similar to that reported for Pb3O4. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. H 2 guaranteed cost control of discrete linear systems

    Directory of Open Access Journals (Sweden)

    Colmenares W.

    2000-01-01

    Full Text Available This paper presents necessary and sufficient conditions for the existence of a quadratically stabilizing output feedback controller which also assures H 2 guaranteed cost performance on a discrete linear uncertain system where the uncertainty is of the norm bounded type. The conditions are presented as a collection of linear matrix inequalities.The solution, however requires a search over a scalar parameter space.

  11. Fast metastable hydrogen atoms from H2 molecules: twin atoms

    Directory of Open Access Journals (Sweden)

    Trimèche A.

    2015-01-01

    Full Text Available It is a difficult task to obtain “twin atoms”, i.e. pairs of massive particles such that one can perform experiments in the same fashion that is routinely done with “twin photons”. One possible route to obtain such pairs is by dissociating homonuclear diatomic molecules. We address this possibility by investigating the production of metastable H(2s atoms coming from the dissociation of cold H2 molecules produced in a Campargue nozzle beam crossing an electron beam from a high intensity pulsed electron gun. Dissociation by electron impact was chosen to avoid limitations of target molecular excited states due to selection rules. Detectors placed several centimeters away from the collision center, and aligned with respect to possible common molecular dissociation channel, analyze the neutral fragments as a function of their time-of-flight (TOF through Lyman-α detection. Evidence for the first time observed coincidence of pairs of H(2s atoms obtained this way is presented.

  12. H2 sensing properties of modified silicon nanowires

    Directory of Open Access Journals (Sweden)

    Latefa Baba Ahmed

    2015-04-01

    Full Text Available It has been found that the silicon nanowires modified with noble metals can be used to fabricate an effective H2 gas sensor in the present study. The preparation and surface modification of silicon nanowires (SiNWs were carried out by chemical methods. The morphology of the silicon nanowires unmodified and modified with nanoparticles of platinum, palladium, silver and gold was investigated using scanning electron microscopy (SEM. The chemical composition of the silicon nanowire layers was studied by secondary ion mass spectroscopy (SIMS and energy dispersive X-ray analysis (EDX. The structures of type metal/SiNWs/p-Si/Al were fabricated. The electrical characterization (I–V was performed in primary vacuum and H2 at different concentrations. It was found that the metal type used to modify the SiNWs strongly influenced the I–V characteristics. The response of these structures toward H2 gas was studied as a function of the metal type. Finally, the sensing characteristics and performance of the sensors were investigated.

  13. Graphene oxide and H2 production from bioelectrochemical graphite oxidation.

    Science.gov (United States)

    Lu, Lu; Zeng, Cuiping; Wang, Luda; Yin, Xiaobo; Jin, Song; Lu, Anhuai; Jason Ren, Zhiyong

    2015-11-17

    Graphene oxide (GO) is an emerging material for energy and environmental applications, but it has been primarily produced using chemical processes involving high energy consumption and hazardous chemicals. In this study, we reported a new bioelectrochemical method to produce GO from graphite under ambient conditions without chemical amendments, value-added organic compounds and high rate H2 were also produced. Compared with abiotic electrochemical electrolysis control, the microbial assisted graphite oxidation produced high rate of graphite oxide and graphene oxide (BEGO) sheets, CO2, and current at lower applied voltage. The resultant electrons are transferred to a biocathode, where H2 and organic compounds are produced by microbial reduction of protons and CO2, respectively, a process known as microbial electrosynthesis (MES). Pseudomonas is the dominant population on the anode, while abundant anaerobic solvent-producing bacteria Clostridium carboxidivorans is likely responsible for electrosynthesis on the cathode. Oxygen production through water electrolysis was not detected on the anode due to the presence of facultative and aerobic bacteria as O2 sinkers. This new method provides a sustainable route for producing graphene materials and renewable H2 at low cost, and it may stimulate a new area of research in MES.

  14. State Specific Stabilization of H+ + H2(j) Collision Complexes

    Science.gov (United States)

    Gerlich, D.; Plašil, R.; Zymak, I.; Hejduk, M.; Jusko, P.; Mulin, D.; Glosík, J.

    2013-10-01

    Stabilization of H3+ collision complexes has been studied at nominal temperatures between 11 and 33 K using a 22-pole radio frequency (rf) ion trap. Apparent binary rate coefficients, k* = kr + k3[H2], have been measured for para- and normal-hydrogen at number densities between some 1011 and 1014 cm-3. The state specific rate coefficients extracted for radiative stabilization, kr(T;j), are all below 2 - 10-16 cm3 s-1. There is a slight tendency to decrease with increasing temperature. In contrast to simple expectations, kr(11 K;j) is for j = 0 a factor of 2 smaller than for j = 1. The ternary rate coefficients for p-H2 show a rather steep T-dependence; however, they are increasing with temperature. The state specific ternary rate coefficients, k3(T;j), measured for j = 0 and derived for j = 1 from measurements with n-H2, differ by an order of magnitude. Most of these surprising observations are in disagreement with predictions from standard association models, which are based on statistical assumptions and the separation of complex formation and competition between stabilization and decay. Most probably, the unexpected collision dynamics are due to the fact that, at the low translational energies of the present experiment, only a small number of partial waves participate. This should make exact quantum mechanical calculations of kr feasible. More complex is three-body stabilization, because it occurs on the H5+ potential energy surface.

  15. Thermodynamics and H2 Transfer in a Methanogenic, Syntrophic Community

    Science.gov (United States)

    Hamilton, Joshua J.; Calixto Contreras, Montserrat; Reed, Jennifer L.

    2015-01-01

    Microorganisms in nature do not exist in isolation but rather interact with other species in their environment. Some microbes interact via syntrophic associations, in which the metabolic by-products of one species serve as nutrients for another. These associations sustain a variety of natural communities, including those involved in methanogenesis. In anaerobic syntrophic communities, energy is transferred from one species to another, either through direct contact and exchange of electrons, or through small molecule diffusion. Thermodynamics plays an important role in governing these interactions, as the oxidation reactions carried out by the first community member are only possible because degradation products are consumed by the second community member. This work presents the development and analysis of genome-scale network reconstructions of the bacterium Syntrophobacter fumaroxidans and the methanogenic archaeon Methanospirillum hungatei. The models were used to verify proposed mechanisms of ATP production within each species. We then identified additional constraints and the cellular objective function required to match experimental observations. The thermodynamic S. fumaroxidans model could not explain why S. fumaroxidans does not produce H2 in monoculture, indicating that current methods might not adequately estimate the thermodynamics, or that other cellular processes (e.g., regulation) play a role. We also developed a thermodynamic coculture model of the association between the organisms. The coculture model correctly predicted the exchange of both H2 and formate between the two species and suggested conditions under which H2 and formate produced by S. fumaroxidans would be fully consumed by M. hungatei. PMID:26147299

  16. Long-term Variability of H2CO Masers in Star-forming Regions

    Science.gov (United States)

    Andreev, N.; Araya, E. D.; Hoffman, I. M.; Hofner, P.; Kurtz, S.; Linz, H.; Olmi, L.; Lorran-Costa, I.

    2017-10-01

    We present results of a multi-epoch monitoring program on variability of 6 cm formaldehyde (H2CO) masers in the massive star-forming region NGC 7538 IRS 1 from 2008 to 2015, conducted with the Green Bank Telescope, the Westerbork Radio Telescope , and the Very Large Array. We found that the similar variability behaviors of the two formaldehyde maser velocity components in NGC 7538 IRS 1 (which was pointed out by Araya and collaborators in 2007) have continued. The possibility that the variability is caused by changes in the maser amplification path in regions with similar morphology and kinematics is discussed. We also observed 12.2 GHz methanol and 22.2 GHz water masers toward NGC 7538 IRS 1. The brightest maser components of CH3OH and H2O species show a decrease in flux density as a function of time. The brightest H2CO maser component also shows a decrease in flux density and has a similar LSR velocity to the brightest H2O and 12.2 GHz CH3OH masers. The line parameters of radio recombination lines and the 20.17 and 20.97 GHz CH3OH transitions in NGC 7538 IRS 1 are also reported. In addition, we observed five other 6 cm formaldehyde maser regions. We found no evidence of significant variability of the 6 cm masers in these regions with respect to previous observations, the only possible exception being the maser in G29.96-0.02. All six sources were also observed in the {{{H}}}213{CO} isotopologue transition of the 6 cm H2CO line; {{{H}}}213{CO} absorption was detected in five of the sources. Estimated column density ratios [{{{H}}}212{CO}]/[{{{H}}}213{CO}] are reported.

  17. Promotion of CO oxidation on PdO(101) by adsorbed H2O

    Science.gov (United States)

    Choi, Juhee; Pan, Li; Mehar, Vikram; Zhang, Feng; Asthagiri, Aravind; Weaver, Jason F.

    2016-08-01

    We investigated the influence of adsorbed H2O on the oxidation of CO on PdO(101) using temperature programmed reaction spectroscopy (TPRS), reflection absorption infrared spectroscopy (RAIRS) and density functional theory (DFT) calculations. We find that water inhibits CO adsorption on PdO(101) by site blocking, but also provides a more facile pathway for CO oxidation compared with the bare oxide surface. In the presence of adsorbed H2O, the oxidation of CO on PdO(101) produces a CO2 TPRS peak that is centered at a temperature 50 K lower than the main CO2 TPRS peak arising from CO oxidation on clean PdO(101) ( 330 vs. 380 K). RAIRS shows that CO continues to adsorb on atop-Pd sites of PdO(101) when H2O is co-adsorbed, and provides no evidence of other reactive intermediates. DFT calculations predict that the CO oxidation mechanism follows the same steps for CO adsorbed on PdO(101) with and without co-adsorbed H2O, wherein an atop-CO species recombines with an oxygen atom from the oxide surface lattice. According to DFT, hydrogen bonding interactions with adsorbed H2O species stabilize the carboxyl-like transition structure and intermediate that result from the initial recombination of CO and O on the PdO(101) surface. This stabilization lowers the energy barrier for CO oxidation on PdO(101) by 10 kJ/mol, in good agreement with our experimental estimate.

  18. U^{28+}-intensity record applying a H_{2}-gas stripper cell

    Directory of Open Access Journals (Sweden)

    Winfried Barth

    2015-04-01

    Full Text Available To meet the Facility for Antiproton and Ion Research science requirements higher beam intensity has to be achieved in the present GSI-accelerator complex. For this an advanced upgrade program for the UNILAC is ongoing. Stripping is a key technology for all heavy ion accelerators. For this an extensive research and development program was carried out to optimize for high brilliance heavy ion operation. After upgrade of the supersonic N_{2}-gas jet (2007, implementation of high current foil stripping (2011 and preliminary investigation of H_{2}-gas jet operation (2012, recently (2014 a new H_{2}-gas cell using a pulsed gas regime synchronized with arrival of the beam pulse has been developed. An obviously enhanced stripper gas density as well as a simultaneously reduced gas load for the pumping system result in an increased stripping efficiency, while the beam emittance remains the same. A new record intensity (7.8 emA for ^{238}U^{28+} beams at 1.4  MeV/u has been achieved applying the pulsed high density H_{2} stripper target to a high intensity ^{238}U^{4+} beam from the VARIS ion source with a newly developed extraction system. The experimental results are presented in detail.

  19. Adsorption and reaction of CO and H2O on WC(0001) surface: A first-principles investigation

    Science.gov (United States)

    Tong, Yu-Jhe; Wu, Shiuan-Yau; Chen, Hsin-Tsung

    2018-01-01

    We have performed a spin-polarized density functional theory (DFT) study for understanding the detailed reaction mechanism of CO and H2O on WC (0001) surface. The adsorption properties and vibrational frequencies of H2O, OH, O, H, CO and CO2 on the WC (0001) surface were illustrated. These results are well in consistent with the experimental observations studied by temperature-programmed desorption (TPD) and high-resolution electron energy loss spectroscopy (HREELS). Based on the adsorption results, potential energy profiles of H2O and OH dehydrogenation and HCO, COH, COOH, and CO2 formation on the WC (0001) surface were predicted. The calculation results demonstrated that the WC (0001) surface as Fe (110) surface exhibits significantly reaction activity toward the dehydrogenation of H2O and OH but less activity toward the formation of HCO, COH, COOH and CO2 compared to the Cu (111) and Pt (111) surfaces.

  20. Mesospheric H2O and H2O2 densities inferred from in situ positive ion composition measurement

    Science.gov (United States)

    Kopp, E.

    1984-01-01

    A model for production and loss of oxonium ions in the high-latitude D-region is developed, based on the observed excess of 34(+) which has been interpreted as H2O2(+). The loss mechanism suggested in the study is the attachment of N2 and/or CO2 in three-body reactions. Furthermore, mesospheric water vapor and H2O2 densities are inferred from measurements of four high-latitude ion compositions, based on the oxonium model. Mixing ratios of hydrogen peroxide of up to two orders of magnitude higher than previous values were obtained. A number of reactions, reaction constants, and a block diagram of the oxonium ion chemistry in the D-region are given.

  1. Effective potentials for H2O-He and H2O-Ar systems. Isotropic induction-dispersion potentials

    Science.gov (United States)

    Starikov, Vitali I.; Petrova, Tatiana M.; Solodov, Alexander M.; Solodov, Alexander A.; Deichuli, Vladimir M.

    2017-05-01

    The vibrational and rotational dependence of the effective isotropic interaction potential of H2O-He and H2O-Ar systems, taken in the form of Lennard-Jones 6-12 potential has been analyzed. The analysis is based on the experimental line broadening (γ) and line shift (δ) coefficients obtained for different vibrational bands of H2O molecule perturbed by He and Ar. The first and second derivatives of the function C(1)(q) for the long-range part of the induction-dispersion potential with respect to the dimensionless normal coordinates q were calculated using literature information for the dipole moment and mean polarizability functions μ(q) and α(q), respectively. These derivatives have been used in the calculations of the quantities which determine the vibrational and rotational dependence of the long-range part of the effective isotropic potential. The optimal set of the derivatives for the function C(1)(q) is proposed. The comparison with the experimental data has been performed.

  2. Capture and dissociation in the complex-forming CH + H2 → CH2 + H, CH + H2 reactions.

    Science.gov (United States)

    González, Miguel; Saracibar, Amaia; Garcia, Ernesto

    2011-02-28

    The rate coefficients for the capture process CH + H(2)→ CH(3) and the reactions CH + H(2)→ CH(2) + H (abstraction), CH + H(2) (exchange) have been calculated in the 200-800 K temperature range, using the quasiclassical trajectory (QCT) method and the most recent global potential energy surface. The reactions, which are of interest in combustion and in astrochemistry, proceed via the formation of long-lived CH(3) collision complexes, and the three H atoms become equivalent. QCT rate coefficients for capture are in quite good agreement with experiments. However, an important zero point energy (ZPE) leakage problem occurs in the QCT calculations for the abstraction, exchange and inelastic exit channels. To account for this issue, a pragmatic but accurate approach has been applied, leading to a good agreement with experimental abstraction rate coefficients. Exchange rate coefficients have also been calculated using this approach. Finally, calculations employing QCT capture/phase space theory (PST) models have been carried out, leading to similar values for the abstraction rate coefficients as the QCT and previous quantum mechanical capture/PST methods. This suggests that QCT capture/PST models are a good alternative to the QCT method for this and similar systems.

  3. Fourfold Clusters of Rovibrational Energies in H2Te Studied With an Ab Initio Potential Energy Function

    Science.gov (United States)

    Jensen, Per; Li, Yan; Hirsch, Gerhard; Buenker, Robert J.; Lee, Timothy J.; Arnold, James O. (Technical Monitor)

    1994-01-01

    We report an ab initio investigation of the cluster effect (i.e., the formation of nearly degenerate, four member groups of rotation-vibration energy levels at higher J and K(sub a). values) in the H2Te molecule. The potential energy function has been calculated ab initio at a total of 334 molecular geometries by means of the CCSD(T) method where the (1s-4f) core electrons of Te were described by an effective core potential. The values of the potential energy function obtained cover the region up to around 10,000/cm above the equilibrium energy. On the basis of the ab initio potential, the rotation-vibration energy spectra of H2Te-130 and its deuterated isotopomers have been calculated with the MORBID (Morse Oscillator Rigid Bender Internal Dynamics) Hamiltonian and computer program. In particular, we have calculated the rotational energy manifolds for J less than or = 40 in the vibrational ground state, the upsilon(sub 2) state, the "first triad" (the upsilon(sub l)/upsilon(sub 3)/2upsilon(sub 2) interacting vibrational states), and the "second triad" (the upsilon(sub 1) + upsilon(sub 2/upsilon(sub 2) + upsilon(sub 3)/3upsilon(sub 2) states) of H2Te-130. We find that the cluster formation in H2Te is very similar to those of of H2Se and H2S, which we have studied previously. However, contrary to semiclassical predictions, we do not determine any significant displacement of the clusters towards lower J values relative to H2Se. Hence the experimental observation of the cluster states in H2Te will be at least as difficult as in H2Se.

  4. Analysis of the particular spill characteristics observed by the Belgian aerial surveillance program during the Tricolor incident

    Energy Technology Data Exchange (ETDEWEB)

    Price, M. [Royal Belgian Inst. for Natural Sciences, Brussels (Belgium)

    2004-07-01

    This presentation described the Tricolor oil spill incident, the remote sensing equipment used to monitor the spill, the observed spill characteristics and the flight data assessment. The spill occurred on December 14, 2002 following a collision between the carrier Tricolor and the container vessel Kariba in French waters in the Zone of Joint Responsibility, close to the Belgian and English borders. The Tricolor sank and 3 more vessels collided with the wreck in the five weeks following the collision, spilling several 100 tons of mostly heavy fuel oil into the sea. The remote sensing equipment aboard Belgian surveillance aircraft noted that freshly spilled oil formed a network of widespread dark oil trails surrounded by light oil fractions. The spill volumes were estimated to be high because of the large extent of the polluted area. Nine months following the spill, the emulsified oil trails had a density close to that of seawater. It was assumed that a cold and thick emulsion had formed and became trapped inside the wreck. Upon release, the emulsion could submerse and resurface. The incident demonstrated that early stage oil sample analysis could help interpret slick behaviour by means of remote sensing. 9 refs., 3 tabs., 1 fig.

  5. Genomic characterization and dynamic methylation of promoter facilitates transcriptional regulation of H2A variants, H2A.1 and H2A.2 in various pathophysiological states of hepatocyte.

    Science.gov (United States)

    Tyagi, Monica; Reddy, Divya; Gupta, Sanjay

    2017-04-01

    Differential expression of homomorphous variants of H2A family of histone H2A.1 and H2A.2 have been associated with hepatocellular carcinoma and maintenance of undifferentiated state of hepatocyte. However, not much is known about the transcriptional regulation of these H2A variants. The current study revealed the presence of 43bp 5'-regulatory region upstream of translation start site and a 26bp 3' stem loop conserved region for both the H2A.1 and H2A.2 variants. However, alignment of both H2A.1 and H2A.2 5'-untranslated region (UTR) sequences revealed no significant degree of homology between them despite the coding exon being very similar amongst the variants. Further, transient transfection coupled with dual luciferase assay of cloned 5' upstream sequences of H2A.1 and H2A.2 of length 1.2 (-1056 to +144) and 1.379kb (-1160 to +219) from experimentally identified 5'UTR in rat liver cell line (CL38) confirmed their promoter activity. Moreover, in silico analysis revealed a presence of multiple CpG sites interspersed in the cloned promoter of H2A.1 and a CpG island near TSS for H2A.2, suggesting that histone variants transcription might be regulated epigenetically. Indeed, treatment with DNMT and HDAC inhibitors increased the expression of H2A.2 with no significant change in H2A.1 levels. Further, methyl DNA immunoprecipitation coupled with quantitative analysis of DNA methylation using real-time PCR revealed hypo-methylation and hyper-methylation of H2A.1 and H2A.2 respectively in embryonic and HCC compared to control adult liver tissue. Collectively, the data suggests that differential DNA methylation on histone promoters is a dynamic player regulating their expression status in different pathophysiological stages of liver. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. The ultraviolet photochemistry of diacetylene - Direct detection of primary products of the metastable C4H2* + C4H2 reaction

    Science.gov (United States)

    Bandy, Ralph E.; Lakshminarayan, Chitra; Frost, Rex K.; Zwier, Timothy S.

    1993-01-01

    The products of diacetylene's ultraviolet photochemistry over the 245-220 nm region were directly determined in experiments where C4H2 was excited within a small reaction tube attached to a pulsed nozzle. The products formed in the collisions of C4H2* with C4H2 were subsequently ionized by vacuum UV radiation (at 118 nm) in the ion source of a time-of-flight mass spectrometer. It was found that the reaction of C4H2* with C4H2 produces C6H2 (+C2H2), C8H2 (+2H,H2), and C8H3 (+H), confirming the results of Glicker and Okabe (1987). Under certain conditions, secondary products were observed. Mechanisms for the observed reactions are proposed.

  7. X Chromosome Inactivation and Differentiation Occur Readily in ES Cells Doubly-Deficient for MacroH2A1 and MacroH2A2

    Science.gov (United States)

    Tanasijevic, Borko; Rasmussen, Theodore P.

    2011-01-01

    Macrohistones (mH2As) are unusual histone variants found exclusively in vertebrate chromatin. In mice, the H2afy gene encodes two splice variants, mH2A1.1 and mH2A1.2 and a second gene, H2afy2, encodes an additional mH2A2 protein. Both mH2A isoforms have been found enriched on the inactive X chromosome (Xi) in differentiated mammalian female cells, and are incorporated into the chromatin of developmentally-regulated genes. To investigate the functional significance of mH2A isoforms for X chromosome inactivation (XCI), we produced male and female embryonic stem cell (ESC) lines with stably-integrated shRNA constructs that simultaneously target both mH2A1 and mH2A2. Surprisingly, we find that female ESCs deficient for both mH2A1 and mH2A2 readily execute and maintain XCI upon differentiation. Furthermore, male and female mH2A-deficient ESCs proliferate normally under pluripotency culture conditions, and respond to several standard differentiation procedures efficiently. Our results show that XCI can readily proceed with substantially reduced total mH2A content. PMID:21738686

  8. A SAFT Equation of State for the H2S-CO2-H2O-NaCl System and Applications for CO2 - H2S Transportation and Geological Storage

    National Research Council Canada - National Science Library

    Ji, Xiaoyan; Zhu, Chen

    2013-01-01

    When H2S is co-injected with CO2, we need to know thermodynamic properties and phase equilibria for the CO2-H2S- H2O-NaCl system in order to evaluate the sequestration capacity, optimal transportation...

  9. First infrared investigations of OCS-H2O, OCS-(H2O)2, and (OCS)2-H2O complexes isolated in solid neon: Highlighting the presence of two isomers for OCS-H2O.

    Science.gov (United States)

    Soulard, P; Madebène, B; Tremblay, B

    2017-06-21

    For the first time, complexes involving carbonyl sulfide (OCS) and water molecules are studied by FTIR in solid neon. Many new absorption bands close to the known fundamental modes for the monomers give evidence for at least three (OCS)n-(H2O)m complexes, noted n:m. With the help of theoretical calculations, two isomers of the 1:1 complex are clearly identified. Concentration effects combined with a detailed vibrational analysis allow for the identification of transitions for the 1:1, 1:2, and 2:1 complexes. Anharmonic coupling constants have been derived from the observations of overtones and combinations.

  10. Periodic H-2 Synthesis for Spacecraft Attitude Control with Magnetometers

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Stoustrup, Jakob

    2004-01-01

    A control synthesis for a spacecraft equipped with a set of magnetorquer coils is addressed. The electromagnetic actuation is particularly attractive for small low-cost spacecraft missions, due to their relatively low price, high reliability, light weight, and low power consumption. The interaction...... between the Earth´s magnetic field and an artificial magnetic field generated by the coils produces a control torque. The magnetic attitude control is intrinsically periodic due to cyclic variation of the geomagnetic field in orbit. The control performance is specified by the generalized H2 operator norm...

  11. Mammal faunal response to the Paleogene hyperthermals ETM2 and H2

    Science.gov (United States)

    Chew, A. E.

    2015-04-01

    Scientists are increasingly turning to deep-time fossil records to decipher the long-term consequences of climate change in the race to preserve modern biotas from anthropogenically driven global warming. "Hyperthermals" are past intervals of geologically rapid global warming that provide the opportunity to study the effects of climate change on existing faunas over thousands of years. A series hyperthermals is known from the early Eocene (∼56-54 million years ago), including the Paleocene-Eocene Thermal Maximum (PETM) and two subsequent hyperthermals, Eocene Thermal Maximum 2 (ETM2) and H2. The later hyperthermals occurred following the onset of warming at the Early Eocene Climatic Optimum (EECO), the hottest sustained period of the Cenozoic. The PETM has been comprehensively studied in marine and terrestrial settings, but the terrestrial biotic effects of ETM2 and H2 are unknown. Their geochemical signatures have been located in the northern part of the Bighorn Basin, WY, USA, and their levels can be extrapolated to an extraordinarily dense, well-studied terrestrial mammal fossil record in the south-central part of the basin. High-resolution, multi-parameter paleoecological analysis reveals significant peaks in species diversity and turnover and changes in abundance and relative body size at the levels of ETM2 and H2 in the south-central Bighorn Basin record. In contrast with the PETM, faunal change at the later hyperthermals is less extreme, does not include immigration and involves a proliferation of body sizes, although abundance shifts tend to favor smaller congeners. Faunal response at ETM2 and H2 is distinctive in its high proportion of species losses potentially related to heightened species vulnerability in response to the changes already underway at the beginning of the EECO. Faunal response at ETM2 and H2 is also distinctive in high proportions of beta richness, suggestive of increased geographic dispersal related to transient increases in habitat

  12. Obesity and asthma: beyond T(H)2 inflammation.

    Science.gov (United States)

    Leiria, Luiz O S; Martins, Milton A; Saad, Mário J A

    2015-02-01

    Obesity is a major risk factor for asthma. Likewise, obesity is known to increase disease severity in asthmatic subjects and also to impair the efficacy of first-line treatment medications for asthma, worsening asthma control in obese patients. This concept is in agreement with the current understanding that some asthma phenotypes are not accompanied by detectable inflammation, and may not be ameliorated by classical anti-inflammatory therapy. There are growing evidences suggesting that the obesity-related asthma phenotype does not necessarily involve the classical T(H)2-dependent inflammatory process. Hormones involved in glucose homeostasis and in the pathogeneses of obesity likely directly or indirectly link obesity and asthma through inflammatory and non-inflammatory pathways. Furthermore, the endocrine regulation of the airway-related pre-ganglionic nerves likely contributes to airway hyperreactivity (AHR) in obese states. In this review, we focused our efforts on understanding the mechanism underlying obesity-related asthma by exploring the T(H)2-independent mechanisms leading to this disease. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Proton ordering in tetragonal and monoclinic H2O ice

    CERN Document Server

    Yen, Fei; Berlie, Adam; Liu, Xiaodi; Goncharov, Alexander F

    2015-01-01

    H2O ice remains one of the most enigmatic materials as its phase diagram reveals up to sixteen solid phases. While the crystal structure of these phases has been determined, the phase boundaries and mechanisms of formation of the proton-ordered phases remain unclear. From high precision measurements of the complex dielectric constant, we probe directly the degree of ordering of the protons in H2O tetragonal ice III and monoclinic ice V down to 80 K. A broadened first-order phase transition is found to occur near 202 K we attribute to a quenched disorder of the protons which causes a continuous disordering of the protons during cooling and metastable behavior. At 126 K the protons in ice III become fully ordered, and for the case of ice V becoming fully ordered at 113 K forming ice XIII. Two triple points are proposed to exist: one at 0.35 GPa and 126 K where ices III, IX and V coexist; and another at 0.35 GPa and 113 K where ices V, IX and XIII coexist. Our findings unravel the underlying mechanism driving th...

  14. Geometric phase effects in the ultracold H + H2 reaction.

    Science.gov (United States)

    Kendrick, B K; Hazra, Jisha; Balakrishnan, N

    2016-10-28

    The H3 system has served as a prototype for geometric phase (GP) effects in bimolecular chemical reactions for over three decades. Despite a large number of theoretical and experimental efforts, no conclusive evidence of GP effects in the integral cross section or reaction rate has been presented until recently [B. Kendrick et al., Phys. Rev. Lett. 115, 153201 (2015)]. Here we report a more detailed account of GP effects in the H + H2(v = 4, j = 0) → H + H2(v', j') (para-para) reaction rate coefficients for temperatures between 1 μK (8.6 × 10(-11) eV) and 100 K (8.6 × 10(-3) eV). The GP effect is found to persist in both vibrationally resolved and total rate coefficients for collision energies up to about 10 K. The GP effect also appears in rotationally resolved differential cross sections leading to a very different oscillatory structure in both energy and scattering angle. It is shown to suppress a prominent shape resonance near 1 K and enhance a shape resonance near 8 K, providing new experimentally verifiable signatures of the GP effect in the fundamental hydrogen exchange reaction. The GP effect in the D + D2 and T + T2 reactions is also examined in the ultracold limit and its sensitivity to the potential energy surface is explored.

  15. H2-saturation of high affinity H2-oxidizing bacteria alters the ecological niche of soil microorganisms unevenly among taxonomic groups

    Directory of Open Access Journals (Sweden)

    Sarah Piché-Choquette

    2016-03-01

    Full Text Available Soil microbial communities are continuously exposed to H2 diffusing into the soil from the atmosphere. N2-fixing nodules represent a peculiar microniche in soil where H2 can reach concentrations up to 20,000 fold higher than in the global atmosphere (0.530 ppmv. In this study, we investigated the impact of H2 exposure on soil bacterial community structure using dynamic microcosm chambers simulating soil H2 exposure from the atmosphere and N2-fixing nodules. Biphasic kinetic parameters governing H2 oxidation activity in soil changed drastically upon elevated H2 exposure, corresponding to a slight but significant decay of high affinity H2-oxidizing bacteria population, accompanied by an enrichment or activation of microorganisms displaying low-affinity for H2. In contrast to previous studies that unveiled limited response by a few species, the relative abundance of 958 bacterial ribotypes distributed among various taxonomic groups, rather than a few distinct taxa, was influenced by H2 exposure. Furthermore, correlation networks showed important alterations of ribotype covariation in response to H2 exposure, suggesting that H2 affects microbe-microbe interactions in soil. Taken together, our results demonstrate that H2-rich environments exert a direct influence on soil H2-oxidizing bacteria in addition to indirect effects on other members of the bacterial communities.

  16. Laboratory studies of H2SO4/H2O binary homogeneous nucleation from the SO2+OH reaction: evaluation of the experimental setup and preliminary results

    Directory of Open Access Journals (Sweden)

    M. Kulmala

    2008-08-01

    Full Text Available Binary homogeneous nucleation (BHN of sulphuric acid and water (H2SO4/H2O is one of the most important atmospheric nucleation processes, but laboratory observations of this nucleation process are very limited and there are also large discrepancies between different laboratory studies. The difficulties associated with these experiments include wall loss of H2SO4 and uncertainties in estimation of H2SO4 concentration ([H2SO4] involved in nucleation. We have developed a new laboratory nucleation setup to study H2SO4/H2O BHN kinetics and provide relatively constrained [H2SO4] needed for nucleation. H2SO4 is produced from the SO2+OH→HSO3 reaction and OH radicals are produced from water vapor UV absorption. The residual [H2SO4] were measured at the end of the nucleation reactor with a chemical ionization mass spectrometer (CIMS. Wall loss factors (WLFs of H2SO4 were estimated by assuming that wall loss is diffusion limited and these calculated WLFs were in good agreement with simultaneous measurements of the initial and residual [H2SO4] with two CIMSs. The nucleation zone was estimated from numerical simulations based on the measured aerosol sizes (particle diameter, Dp and [H2SO4]. The measured BHN rates (J ranged from 0.01–220 cm−3 s−1 at the initial and residual [H2SO4] from 108−1010 cm−3, a temperature of 288 K and relative humidity (RH from 11–23%; J increased with increasing [H2SO4] and RH. J also showed a power dependence on [H2SO4] with the exponential power of 3–8. These power dependences are consistent with other laboratory studies under similar [H2SO4] and RH, but different from atmospheric field observations which showed that particle number concentrations are often linearly dependent on [H2SO4]. These results, together with a higher [H2SO4] threshold (108–109 cm−3 needed to produce the unit J measured from the laboratory studies compared to the atmospheric conditions (106–107 cm−3, imply that H2SO4/H2O BHN alone is

  17. Dynamical effects in dissociative adsorption: Quantum state-resolved studies of H(2) scattering from Pd and Cu

    Science.gov (United States)

    Gostein, Michael

    The effects of molecular rotation and vibration in the dynamics of H2 scattering from Pd(111) and Cu(110) were studied using molecular beam and laser spectroscopy techniques. These studies test state-of-the- art theoretical simulations of molecule-surface interactions, a fundamental understanding of which is relevant to diverse fields in science and technology. Experiments on the rotational state dependence of H2 dissociation on Pd(111) were motivated by recent theoretical results concerning the concept of dynamical steering. This concept has been invoked to explain the enhancement of sticking at low translational energy for H2 incident on certain metals. It suggests that sticking should also be enhanced for low rotational energy in these systems. The experiments presented here qualitatively confirm this prediction. For incident translational energies from 31- 95 meV, the H2/Pd(111) sticking coefficient goes down as the rotational quantum number J is raised from 0 to 3. It then increases for J = 4 and 5, which is consistent with rotational energy also helping directly overcome the activation barrier. A fraction of the scattered H2 molecules are also rotationally excited. This occurs directly upon scattering but is activated by the surface temperature, not the incident translational energy. This behavior is not explained by current theoretical treatments and requires further exploration. Experiments on the vibrational state dependence of H2 scattering from Cu(110) and Pd(111) were motivated by continued considerations of activation barriers to dissociative adsorption, since vibrational energy assists in surmounting barriers which occur 'late' along the reaction path. The survival probability of H2 in the rovibrational state (v = 1, J = 1), prepared by stimulated Raman scattering, was measured for scattering from each surface. In both cases the (v = 1, J = 1) survival probability is smaller than that of the ground vibrational state, in accord with expectations for a

  18. Ni(dmgH)2 complex coupled with metal-organic frameworks MIL-101(Cr) for photocatalytic H2 evolution under visible light irradiation

    National Research Council Canada - National Science Library

    Rong Wang; Li Wu; Bryant Chica; Lina Gu; Gengsheng Xu; Yupeng Yuan

    2017-01-01

    .... Lacking native active sites (so-called co-catalyst) for H2 generation motivates the incorporation of noble metals and their molecular complexes, hydrogenase active site mimics into MOFs to promote H2 generation...

  19. The effectiveness of a community-based program for reducing the incidence of falls in the elderly: a randomized trial.

    Science.gov (United States)

    Clemson, Lindy; Cumming, Robert G; Kendig, Hal; Swann, Megan; Heard, Robert; Taylor, Kirsty

    2004-09-01

    To test whether Stepping On, a multifaceted community-based program using a small-group learning environment, is effective in reducing falls in at-risk people living at home. A randomized trial with subjects followed for 14 months. The interventions were conducted in community venues, with a follow-up home visit. Three hundred ten community residents aged 70 and older who had had a fall in the previous 12 months or were concerned about falling. The Stepping On program aims to improve fall self-efficacy, encourage behavioral change, and reduce falls. Key aspects of the program are improving lower-limb balance and strength, improving home and community environmental and behavioral safety, encouraging regular visual screening, making adaptations to low vision, and encouraging medication review. Two-hour sessions were conducted weekly for 7 weeks, with a follow-up occupational therapy home visit. The primary outcome measure was falls, ascertained using a monthly calendar mailed by each participant. The intervention group experienced a 31% reduction in falls (relative risk (RR)=0.69, 95% confidence interval (CI)=0.50-0.96; P=.025). This was a clinically meaningful result demonstrating that the Stepping On program was effective for community-residing elderly people. Secondary analysis of subgroups showed that it was particularly effective for men (n=80; RR=0.32, 95% CI=0.17-0.59). The results of this study renew attention to the idea that cognitive-behavioral learning in a small-group environment can reduce falls. Stepping On offers a successful fall-prevention option. Copyright 2004 American Geriatrics Society

  20. An exact calculation of the N2+ and H2+ influx at cathode surface in N2–H2 discharges

    Directory of Open Access Journals (Sweden)

    K.S. Suraj

    2014-01-01

    Full Text Available An exact calculation of N2+ and H2+ influx, at cathode surface in N2–H2 discharge, has been derived using electron impact ionization cross-section at plasma sheath boundary. The analytical formula is very convenient in practical applications. Through the analysis of experimental parameters for glow discharge plasma nitriding, the formula explains, why treatment in an N2–H2 mixture with H2 percentage ∼70% gives most enhanced result.

  1. Environmental regulation of H2 utilization ( (3)H 2 exchange) among natural and laboratory populations of N2 and non-N 2 fixing phytoplankton.

    Science.gov (United States)

    Paerl, H W

    1983-07-01

    Regulation of H2 utilization, as monitored by the hydrogenase-mediated(3)H2 exchange reaction, was examined among phytoplankton communitiesin situ and populations in culture. During a 2-year study in the Chowan River, North Carolina, at least 2 major groups of phytoplankton dominated(3)H2 exchange rates. They included N2 fixing cyanobacteria and NO3 (})- utilizing genera. Utilization of(3)H2 by N2 fixers was mainly dark-mediated, whereas(3)H2 utilization associated with periods of NO3 (})- abundance revealed an increasing dependence on light. Inhibitors of N2 fixation (C2H2 and NH4 (+)) negatively affected(3)H2 utilization, substantiating previous findings that close metabolic coupling of both processes exists among N2 fixing cyanobacteria. Conversely, NO3 (})- stimulated(3)H2 utilization among N2 and non-N2 fixing genera, particularly under illuminated conditions. A variety of environmental factors were shown to control(3)H2 exchange. In addition to the nitrogen sources discussed above, dissolved O2, photosynthetically available radiation (PAR), temperature, and pH changes altered(3)H2 exchange rates. It is likely that other factors not addressed here could also affect(3)H2 exchange rates. At least 2 ecological benefits from H2 utilization in natural phytoplankton can be offered. They include the simultaneous generation of adenosine triphosphate (ATP) and consumption of O2 during the oxidation of H2 via an oxyhydrogen or "Knallgas" reaction. Both processes could help sustain phytoplankton, and particularly cyanobacterial, bloom intensity under natural conditions when O2 supersaturation is common in surface waters. H2 utilization appeared to be a general feature of natural and laboratory phytoplankton populations. The magnitudes of(3)H2 utilization rates were directly related to community biomass. Although it can be shown that utilization rates are controlled by specific environmental factors, the potential relationships between H2 utilization and phytoplankton

  2. A comparison of quantum and classical dynamics of H2 dissociation on Cu(111)

    DEFF Research Database (Denmark)

    Kinnersley, A.; Darling, G.R.; Holloway, S.

    1996-01-01

    ground state. This subtracts from the problem the largest quantum degree of freedom with the consequence that broadly speaking, quantum and classical results for the dissociation as a function of initial rotational state and incidence angle agree well. One feature arising from the calculations...... is that for the first time we have shown how the quantized nature of motion near the transition state affects experimental observables. We demonstrate that hitherto neglected structure in dissociation probabilities may be traced to quantized hindered rotational and translational motion. An additional consequence......A quantitative comparison of the results from quantum and classical computations of the dissociation of H-2 on the ab initio Cu(111) surface is presented. In order to initiate a detailed comparison of the classical and quantum methods, we chose to investigate motion on the vibrationally adiabatic...

  3. Resveratrol induces cellular senescence with attenuated mono-ubiquitination of histone H2B in glioma cells

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Zhen; Xu, Michael S.; Barnett, Tamara L. [Nevada Cancer Institute, Las Vegas, NV 89135 (United States); Xu, C. Wilson, E-mail: wxu@nvcancer.org [Nevada Cancer Institute, Las Vegas, NV 89135 (United States)

    2011-04-08

    Research highlights: {yields} Resveratrol induces cellular senescence in glioma cell. {yields} Resveratrol inhibits mono-ubiquitination of histone H2B at K120. {yields} Depletion of RNF20, phenocopies the inhibitory effects of resveratrol. {yields} Mono-ubiquitination of histone H2B at K120 is a novel target of resveratrol. {yields} RNF20 inhibits cellular senescence in proliferating glioma cells. -- Abstract: Resveratrol (3,4',5-trihydroxy-trans-stilbene), a polyphenol naturally occurring in grapes and other plants, has cancer chemo-preventive effects and therapeutic potential. Although resveratrol modulates multiple pathways in tumor cells, how resveratrol or its affected pathways converge on chromatin to mediate its effects is not known. Using glioma cells as a model, we showed here that resveratrol inhibited cell proliferation and induced cellular hypertrophy by transforming spindle-shaped cells to enlarged, irregular and flatten-shaped ones. We further showed that resveratrol-induced hypertrophic cells expressed senescence-associated-{beta}-galactosidase, suggesting that resveratrol-induced cellular senescence in glioma cells. Consistent with these observations, we demonstrated that resveratrol inhibited clonogenic efficiencies in vitro and tumor growth in a xenograft model. Furthermore, we found that acute treatment of resveratrol inhibited mono-ubiquitination of histone H2B at K120 (uH2B) in breast, prostate, pancreatic, lung, brain tumor cells as well as primary human cells. Chronic treatment with low doses of resveratrol also inhibited uH2B in the resveratrol-induced senescent glioma cells. Moreover, we showed that depletion of RNF20, a ubiquitin ligase of histone H2B, inhibited uH2B and induced cellular senescence in glioma cells in vitro, thereby recapitulated the effects of resveratrol. Taken together, our results suggest that uH2B is a novel direct or indirect chromatin target of resveratrol and RNF20 plays an important role in inhibiting cellular

  4. Investigating Superhydrogenated Polycyclic Aromatic Hydrocarbons as catalysts for Interstellar H2 formation

    DEFF Research Database (Denmark)

    Simonsen, Frederik Doktor Skødt

    aromatic hydrocarbons (PAHs). PAHs are believed to account for up to 20% of the available carbon in the ISM and have been observed, with significantly large abundances, alongside H2 [2]. Here we investigate the adsorption pattern of hydrogen/deuterium on coronene, C24H12. Both scanning tunneling microscopy...... (STM) and temperature programmed desorption (TPD) techniques have been used. Coronene monolayers were prepared on highly ordered pyrolytic graphite (HOPG) and exposed to different fluences of hot (2300K) or cold (1000K) H or D atoms. STM images show bright spots on the coronene monolayers after...

  5. Investigating Superhydrogenated Polycyclic Aromatic Hydrocarbons as catalysts for Interstellar H2 formation

    DEFF Research Database (Denmark)

    Simonsen, Frederik Doktor Skødt

    2016-01-01

    account for the observed abundances[1]. Therefore new formation routes are needed and lately attention has been drawn towards molecules called polycyclic aromatic hydrocarbons (PAHs). PAHs are believed to account for up to 20% of the available carbon in the ISM and have been observed, with significantly...... large abundances, alongside H2[2]. To investigate the the abstraction and adsoption patterns of hydrogen/deuterium on coronene, C24H12 (a PAH), we used temperature programmed desorption (TPD). Coronene monolayers were prepared on graphite and exposed to different fluences of 1000 K H or D atoms...

  6. Investigating Superhydrogenated Polycyclic Aromatic Hydrocarbons on HOPG and their catalytic abilities of H2 formation

    DEFF Research Database (Denmark)

    Simonsen, Frederik Doktor Skødt

    molecules called polycyclic aromatic hydrocarbons (PAHs). PAHs are believed to account for up to 20% of the available carbon in the ISM and have been observed, with significantly large abundances, alongside H2[2]. Here we investigate the adsorption pattern of hydrogen/deuterium on coronene, C24H12 (a PAH......). Both scanning tunneling microscopy (STM) and temperature programmed desorption (TPD) techniques have been used. Coronene monolayers were prepared on graphite and exposed to different fluences of 1000K H or D atoms. STM images show brigth spots on the coronene monolayers after hydrogenation indicating...

  7. Antiapoptotic Actions of Methyl Gallate on Neonatal Rat Cardiac Myocytes Exposed to H2O2

    Directory of Open Access Journals (Sweden)

    Sandhya Khurana

    2014-01-01

    Full Text Available Reactive oxygen species trigger cardiomyocyte cell death via increased oxidative stress and have been implicated in the pathogenesis of cardiovascular diseases. The prevention of cardiomyocyte apoptosis is a putative therapeutic target in cardioprotection. Polyphenol intake has been associated with reduced incidences of cardiovascular disease and better overall health. Polyphenols like epigallocatechin gallate (EGCG can reduce apoptosis of cardiomyocytes, resulting in better health outcomes in animal models of cardiac disorders. Here, we analyzed whether the antioxidant N-acetyl cysteine (NAC or polyphenols EGCG, gallic acid (GA or methyl gallate (MG can protect cardiomyocytes from cobalt or H2O2-induced stress. We demonstrate that MG can uphold viability of neonatal rat cardiomyocytes exposed to H2O2 by diminishing intracellular ROS, maintaining mitochondrial membrane potential, augmenting endogenous glutathione, and reducing apoptosis as evidenced by impaired Annexin V/PI staining, prevention of DNA fragmentation, and cleaved caspase-9 accumulation. These findings suggest a therapeutic value for MG in cardioprotection.

  8. Insecticidal Activity of [Cu(H2NTA2].2H2O in Aedes aegypti Larvae (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Alessandra Ramos Lima

    2015-12-01

    Full Text Available The demand for new insecticides and alternative strategies for the population control of Aedes aegypti has stimulated research to obtain new compounds with broad biological activity. Accordingly, the dihydrogen nitrilotriacetate complex of copper (II dihydrate, [Cu(H2NTA2].2H2O, was synthesized by the stoichiometric reaction of nitrilotriacetic acid (H3NTA hydroxide with basic copper carbonate (II (Cu2(OH2CO3 and characterized by the spectroscopic techniques UV-Vis and FT-IR. The biological toxicity in A. aegypti was determined by bioassay using concentrations ranging from 90.0 mg L−1 to 897.4 mg L−1. The LC50 obtained was 146.11 mg L−1 [132.18–160.10] and the LT50 obtained at a concentration of 897.4 mg L−1 was 70.61 min [38.21–94.90]. The results showed that the complex obtained in this work is a potential metal-insecticide. DOI: http://dx.doi.org/10.17807/orbital.v7i4.735 

  9. Does residual H2O2 result in inhibitory effect on enhanced anaerobic digestion of sludge pretreated by microwave-H2O2 pretreatment process?

    Science.gov (United States)

    Liu, Jibao; Jia, Ruilai; Wang, Yawei; Wei, Yuansong; Zhang, Junya; Wang, Rui; Cai, Xing

    2017-04-01

    This study investigated the effects of residual H2O2 on hydrolysis-acidification and methanogenesis stages of anaerobic digestion after microwave-H2O2 (MW-H2O2) pretreatment of waste activated sludge (WAS). Results showed that high sludge solubilization at 35-45 % was achieved after pretreatment, while large amounts of residual H2O2 remained and refractory compounds were thus generated with high dosage of H2O2 (0.6 g H2O2/g total solids (TS), 1.0 g H2O2/g TS) pretreatment. The residual H2O2 not only inhibited hydrolysis-acidification stage mildly, such as hydrolase activity, but also had acute toxic effect on methanogens, resulting in long lag phase, low methane yield rate, and no increase of cumulative methane production during the 30-day BMP tests. When the low dosage of H2O2 at 0.2 g H2O2/g TS was used in MW-H2O2 pretreatment, sludge anaerobic digestion was significantly enhanced. The cumulative methane production increased by 29.02 %, but still with a lag phase of 1.0 day. With removing the residual H2O2 by catalase, the initial lag phase of hydrolysis-acidification stage decreased from 1.0 to 0.5 day.

  10. Evaluation of plasma H2S levels and H2S synthesis in streptozotocin induced Type-2 diabetes-an experimental study based on Swietenia macrophylla seeds

    Directory of Open Access Journals (Sweden)

    Moumita Dutta

    2014-05-01

    Conclusions: Although considering a small sample size, it can conclude that the fasting blood glucose levels are inversely related to plasma H2S levels as well as H2S synthesis activity in plasma and the extract of S. macrophylla is associated with increased plasma H2S levels with effective lowering of blood glucose in streptozotocin induced diabetic rats.

  11. Ni(dmgH2 complex coupled with metal-organic frameworks MIL-101(Cr for photocatalytic H2 evolution under visible light irradiation

    Directory of Open Access Journals (Sweden)

    Rong Wang

    2017-03-01

    Full Text Available Metal-organic frameworks (MOFs have been tremendously used as photocatalysts for H2 generation in recent years. Lacking native active sites (so-called co-catalyst for H2 generation motivates the incorporation of noble metals and their molecular complexes, hydrogenase active site mimics into MOFs to promote H2 generation. We herein report an noble-metal-free photocatalytic H2 generation system consisting of Erythrosin B dye-sensitized MIL-101(Cr as a light absorber and Ni(dmgH2 as a co-catalyst. It is found that Ni(dmgH2 can serve as an efficient co-catalyst to boost H2 generation in the presence of triethanolamine (TEOA as an electron donor under visible light irradiation. The optimal MIL-101(Cr/Ni(dmgH2 hybrid (5 wt% Ni(dmgH2 displays a hydrogen H2 rate of 45.5 μmol h−1, which is 10 times greater than the control sample without Ni(dmgH2 loading. This paper provides a novel design route for active H2 generation systems by combining molecular complexes of earth-abundant metal and MOFs photocatalysts.

  12. H2A.Z: view from the top.

    Science.gov (United States)

    Zlatanova, Jordanka; Thakar, Amit

    2008-02-01

    For a couple of decades the chromatin field has endured undeserved neglect. Indeed, what could be so exciting about a monotonous repeating structure whose purpose in life was to package DNA? Chromatin glamour is triumphantly back, due to the realization that chromatin is a major player in the regulation of gene expression and other nuclear processes that occur on the DNA template. The dynamics of the structure that regulates transcription is itself regulated by a variety of complex processes, including histone postsynthetic modifications, chromatin remodeling, and the use of nonallelic histone variants. This review is an attempt to understand the mechanisms of action of the evolutionarily conserved variant H2A.Z, a player with a variety of seemingly unrelated, even contrary, functions. This attempt was prompted by the recent avalanche of genome-wide studies that provide insights that were unthinkable until very recently.

  13. Utilization of membranes for H2O recycle system

    Science.gov (United States)

    Ohya, H.; Oguchi, M.

    1986-01-01

    Conceptual studies of closed ecological life support systems (CELSS) carried out at NAL in Japan for a water recycle system using membranes are reviewed. The system will treat water from shower room, urine, impure condensation from gas recycle system, and so on. The H2O recycle system is composed of prefilter, ultrafiltration membrane, reverse osmosis membrane, and distillator. Some results are shown for a bullet train of toilet-flushing water recycle equipment with an ultraviltration membrane module. The constant value of the permeation rate with a 4.7 square meters of module is about 70 1/h after 500th of operation. Thermovaporization with porous polytetrafluorocarbon membrane is also proposed to replce the distillator.

  14. Does the FIFA 11+ Injury Prevention Program Reduce the Incidence of ACL Injury in Male Soccer Players?

    Science.gov (United States)

    Silvers-Granelli, Holly J; Bizzini, Mario; Arundale, Amelia; Mandelbaum, Bert R; Snyder-Mackler, Lynn

    2017-10-01

    The FIFA 11+ injury prevention program has been shown to decrease the risk of soccer injuries in men and women. The program has also been shown to decrease time loss resulting from injury. However, previous studies have not specifically investigated how the program might impact the rate of anterior cruciate ligament (ACL) injury in male soccer players. The purpose of this study was to examine if the FIFA 11+ injury prevention program can (1) reduce the overall number of ACL injuries in men who play competitive college soccer and whether any potential reduction in rate of ACL injuries differed based on (2) game versus practice setting; (3) player position; (4) level of play (Division I or II); or (5) field type. This study was a prospective cluster randomized controlled trial, which was conducted in 61 Division I and Division II National Collegiate Athletic Association men's soccer teams over the course of one competitive soccer season. The FIFA 11+ is a 15- to 20-minute on-the-field dynamic warm-up program used before training and games and was utilized as the intervention throughout the entire competitive season. Sixty-five teams were randomized: 34 to the control group (850 players) and 31 to the intervention group (675 players). Four intervention teams did not complete the study and did not submit their data, noting insufficient time to complete the program, reducing the number for per-protocol analysis to 61. Compliance to the FIFA 11+ program, athletic exposures, specific injuries, ACL injuries, and time loss resulting from injury were collected and recorded using a secure Internet-based system. At the end of the season, the data in the injury surveillance system were crosshatched with each individual institution's internal database. At that time, the certified athletic trainer signed off on the injury collection data to confirm their accuracy and completeness. A lower proportion of athletes in the intervention group experienced knee injuries (25% [34 of

  15. Observation of Heavy Rydberg States in H_2 and HD

    Science.gov (United States)

    Beyer, Maximilian; Merkt, Frederic

    2017-06-01

    The binding energies of the hydrogen atom are given by the Rydberg formula E_n = - {{R}_∞μ/m_e}/{(n-δ)^2}, where the quantum defect δ vanishes in the case of a pure Coulomb potential. Heavy Rydberg systems can be realized when the electron is replaced by an anion, which leads in the case of H^+H^- to an almost 1000 times larger Rydberg constant and to an infinite number of vibrational states. In the diabatic molecular basis, these ion-pair states are described by long-range Coulomb potentials with ^1Σ_g^+ and ^1Σ_u^+ symmetry. In this basis, the level energies are described by an almost energy-independent, nonzero quantum defect, reflecting the finite size of H^-. Strong interactions at small internuclear distances lead to strong variation of δ with n. Gerade [2] and ungerade [3] ion-pair states have been observed in H_2 with principal quantum numbers up to n=240. The quantum defects in this range were found to vary with energy, indicating the inadequacy of a pure diabatic picture. Spectra of ungerade heavy Rydberg states of H_2 with n=160-520 showing that the quantum defect only becomes energy independent for n>350 will be presented, supporting the description using a diabatic basis. I will also present first observations of ion-pair states in HD, showing two series of heavy Rydberg states, H^+D^- and H^-D^+, which have different series limits. The experimental results will be discussed and compared with calculations using both an adiabatic and a diabatic basis. [1] S. Pan, and F. H. Mies, J. Chem. Phys. 89, 3096 (1988). [2] M. O. Vieitez, T. I. Ivanov, E. Reinhold, C. A. de Lange, and W. Ubachs, Phys. Rev. Lett. 101, 163001 (2008). [3] R. C. Ekey, and E. F. McCormack, Phys. Rev. A 84, 020501(R) (2011).

  16. 78 FR 69541 - Labor Certification Process for Logging Employment and Non-H-2A Agricultural Employment

    Science.gov (United States)

    2013-11-20

    ... for employers in the logging industry utilizing foreign workers. The regulations became obsolete after...(c)(4), was to include within the program requirements for temporary employment of foreign workers in agriculture (H-2A) employers seeking to temporarily employ foreign workers in logging occupations. The...

  17. 75 FR 38145 - Announcing the New National Electronic Job Registry for Use in the H-2A Temporary Agricultural...

    Science.gov (United States)

    2010-07-01

    ... Employment and Training Administration Announcing the New National Electronic Job Registry for Use in the H-2A Temporary Agricultural Labor Certification Program AGENCY: Employment and Training Administration, Department of Labor. ACTION: Notice. SUMMARY: The Employment and Training Administration (ETA) is announcing...

  18. Increasing extracellular H2O2 produces a bi-phasic response in intracellular H2O2, with peroxiredoxin hyperoxidation only triggered once the cellular H2O2-buffering capacity is overwhelmed.

    Science.gov (United States)

    Tomalin, Lewis Elwood; Day, Alison Michelle; Underwood, Zoe Elizabeth; Smith, Graham Robert; Dalle Pezze, Piero; Rallis, Charalampos; Patel, Waseema; Dickinson, Bryan Craig; Bähler, Jürg; Brewer, Thomas Francis; Chang, Christopher Joh-Leung; Shanley, Daryl Pierson; Veal, Elizabeth Ann

    2016-06-01

    Reactive oxygen species, such as H2O2, can damage cells but also promote fundamental processes, including growth, differentiation and migration. The mechanisms allowing cells to differentially respond to toxic or signaling H2O2 levels are poorly defined. Here we reveal that increasing external H2O2 produces a bi-phasic response in intracellular H2O2. Peroxiredoxins (Prx) are abundant peroxidases which protect against genome instability, ageing and cancer. We have developed a dynamic model simulating in vivo changes in Prx oxidation. Remarkably, we show that the thioredoxin peroxidase activity of Prx does not provide any significant protection against external rises in H2O2. Instead, our model and experimental data are consistent with low levels of extracellular H2O2 being efficiently buffered by other thioredoxin-dependent activities, including H2O2-reactive cysteines in the thiol-proteome. We show that when extracellular H2O2 levels overwhelm this buffering capacity, the consequent rise in intracellular H2O2 triggers hyperoxidation of Prx to thioredoxin-resistant, peroxidase-inactive form/s. Accordingly, Prx hyperoxidation signals that H2O2 defenses are breached, diverting thioredoxin to repair damage. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  19. Transport of H2S and HS(-) across the human red blood cell membrane: rapid H2S diffusion and AE1-mediated Cl(-)/HS(-) exchange.

    Science.gov (United States)

    Jennings, Michael L

    2013-11-01

    The rates of H2S and HS(-) transport across the human erythrocyte membrane were estimated by measuring rates of dissipation of pH gradients in media containing 250 μM H2S/HS(-). Net acid efflux is caused by H2S/HS(-) acting analogously to CO2/HCO3(-) in the Jacobs-Stewart cycle. The steps are as follows: 1) H2S efflux through the lipid bilayer and/or a gas channel, 2) extracellular H2S deprotonation, 3) HS(-) influx in exchange for Cl(-), catalyzed by the anion exchange protein AE1, and 4) intracellular HS(-) protonation. Net acid transport by the Cl(-)/HS(-)/H2S cycle is more efficient than by the Cl(-)/HCO3(-)/CO2 cycle because of the rapid H2S-HS(-) interconversion in cells and medium. The rates of acid transport were analyzed by solving the mass flow equations for the cycle to produce estimates of the HS(-) and H2S transport rates. The data indicate that HS(-) is a very good substrate for AE1; the Cl(-)/HS(-) exchange rate is about one-third as rapid as Cl(-)/HCO3(-) exchange. The H2S permeability coefficient must also be high (>10(-2) cm/s, half time <0.003 s) to account for the pH equilibration data. The results imply that H2S and HS(-) enter erythrocytes very rapidly in the microcirculation of H2S-producing tissues, thereby acting as a sink for H2S and lowering the local extracellular concentration, and the fact that HS(-) is a substrate for a Cl(-)/HCO3(-) exchanger indicates that some effects of exogenous H2S/HS(-) may not result from a regulatory role of H2S but, rather, from net acid flux by H2S and HS(-) transport in a Jacobs-Stewart cycle.

  20. Ni(dmgH)2 complex coupled with metal-organic frameworks MIL-101(Cr) for photocatalytic H2 evolution under visible light irradiation

    OpenAIRE

    Wang, Rong; Wu, Li; Chica, Bryant; Gu, Lina; Xu, Gengsheng; Yuan, Yupeng

    2017-01-01

    Metal-organic frameworks (MOFs) have been tremendously used as photocatalysts for H2 generation in recent years. Lacking native active sites (so-called co-catalyst) for H2 generation motivates the incorporation of noble metals and their molecular complexes, hydrogenase active site mimics into MOFs to promote H2 generation. We herein report an noble-metal-free photocatalytic H2 generation system consisting of Erythrosin B dye-sensitized MIL-101(Cr) as a light absorber and Ni(dmgH)2 as a co-cat...

  1. Catalase activity is stimulated by H2O2 in rich culture medium and is required for H2O2 resistance and adaptation in yeast

    OpenAIRE

    Dorival Martins; Ann M. English

    2014-01-01

    Catalases are efficient scavengers of H2O2 and protect cells against H2O2 stress. Examination of the H2O2 stimulon in Saccharomyces cerevisiae revealed that the cytosolic catalase T (Ctt1) protein level increases 15-fold on H2O2 challenge in synthetic complete media although previous work revealed that deletion of the CCT1 or CTA1 genes (encoding peroxisomal/mitochondrial catalase A) does not increase the H2O2 sensitivity of yeast challenged in phosphate buffer (pH 7.4). This we attributed to...

  2. Plasma Concentrations of Per- and Polyfluoroalkyl Substances at Baseline and Associations with Glycemic Indicators and Diabetes Incidence among High-Risk Adults in the Diabetes Prevention Program Trial.

    Science.gov (United States)

    Cardenas, Andres; Gold, Diane R; Hauser, Russ; Kleinman, Ken P; Hivert, Marie-France; Calafat, Antonia M; Ye, Xiaoyun; Webster, Thomas F; Horton, Edward S; Oken, Emily

    2017-10-02

    Several per- and polyfluoroalkyl substances (PFAS) are ubiquitous anthropogenic pollutants almost universally detected in humans. Experimental evidence indicates that PFAS alter glucose metabolism and insulin secretion. However, epidemiological studies have yielded inconsistent results. We sought to examine associations between plasma PFAS concentrations, glycemic indicators, and diabetes incidence among high-risk adults. Within the Diabetes Prevention Program (DPP), a trial for the prevention of type 2 diabetes among high-risk individuals, we quantified baseline plasma concentrations of nine PFAS among 957 participants randomized to a lifestyle intervention or placebo. We evaluated adjusted associations for plasma PFAS concentrations with diabetes incidence and key glycemic indicators measured at baseline and annually over up to 4.6 y. Plasma PFAS concentrations were similar to those reported in the U.S. population in 1999-2000. At baseline, in cross-sectional analysis, a doubling in plasma perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) concentrations was associated with higher homeostatic model assessment of insulin resistance (HOMA-IR) [βPFOS=0.39; 95% confidence interval (CI): 0.13, 0.66; βPFOA=0.64; 95% CI: 0.34, 0.94], β-cell function (HOMA-β) (βPFOS=9.62; 95% CI: 1.55, 17.70; βPFOA=15.93; 95% CI: 6.78, 25.08), fasting proinsulin (βPFOS=1.37 pM; 95% CI: 0.50, 2.25; βPFOA=1.71 pM; 95% CI: 0.72, 2.71), and glycated hemoglobin (HbA1c) (βPFOS=0.03%; 95% CI: 0.002, 0.07; βPFOA=0.04%; 95% CI: 0.001, 0.07). There was no strong evidence of associations between plasma PFAS concentrations and diabetes incidence or prospective changes in glycemic indicators during the follow-up period. At baseline, several PFAS were cross-sectionally associated with small differences in markers of insulin secretion and β-cell function. However, there was limited evidence suggesting that PFAS concentrations are associated with diabetes incidence or

  3. Putrescine protects hulless barley from damage due to UV-B stress via H2S- and H2O2-mediated signaling pathways.

    Science.gov (United States)

    Li, Qien; Wang, Zhaofeng; Zhao, Yanning; Zhang, Xiaochen; Zhang, Shuaijun; Bo, Letao; Wang, Yao; Ding, Yingfeng; An, Lizhe

    2016-05-01

    In hulless barley, H 2 S mediated increases in H 2 O 2 induced by putrescine, and their interaction enhanced tolerance to UV-B by maintaining redox homeostasis and promoting the accumulation of UV-absorbing compounds. This study investigated the possible relationship between putrescence (Put), hydrogen sulfide (H2S) and hydrogen peroxide (H2O2) as well as the underlying mechanism of their interaction in reducing UV-B induced damage. UV-B radiation increased electrolyte leakage (EL) and the levels of malondialdehyde (MDA) and UV-absorbing compounds but reduced antioxidant enzyme activities and glutathione (GSH) and ascorbic acid (AsA) contents. Exogenous application of Put, H2S or H2O2 reduced some of the above-mentioned negative effects, but were enhanced by the addition of Put, H2S and H2O2 inhibitors. Moreover, the protective effect of Put against UV-B radiation-induced damage to hulless barley was diminished by DL-propargylglycine (PAG, a H2S biosynthesis inhibitor), hydroxylamine (HT, a H2S scavenger), diphenylene iodonium (DPI, a PM-NADPH oxidase inhibitor) and dimethylthiourea (DMTU, a ROS scavenger), and the effect of Put on H2O2 accumulation was abolished by HT. Taken together, as the downstream component of the Put signaling pathway, H2S mediated H2O2 accumulation, and H2O2 induced the accumulation of UV-absorbing compounds and maintained redox homeostasis under UV-B stress, thereby increasing the tolerance of hulless barley seedlings to UV-B stress.

  4. Increased H$_2$CO production in the outer disk around HD 163296

    OpenAIRE

    Carney, M. T.; Hogerheijde, M. R.; Loomis, R. A.; Salinas, V. N.; Öberg, K.I.; Qi, C.; Wilner, D. J.

    2017-01-01

    Three formaldehyde lines were observed (H$_2$CO 3$_{03}$--2$_{02}$, H$_2$CO 3$_{22}$--2$_{21}$, and H$_2$CO 3$_{21}$--2$_{20}$) in the protoplanetary disk around the Herbig Ae star HD 163296 with ALMA at 0.5 arcsecond (60 AU) spatial resolution. H$_2$CO 3$_{03}$--2$_{02}$ was readily detected via imaging, while the weaker H$_2$CO 3$_{22}$--2$_{21}$ and H$_2$CO 3$_{21}$--2$_{20}$ lines required matched filter analysis to detect. H$_2$CO is present throughout most of the gaseous disk, extending...

  5. High-Level ab initio electronic structure calculations of Water Clusters (H2O)16 and (H2O)17: a new global minimum for (H2O)16

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Soohaeng; Apra, Edoardo; Zeng, Xiao Cheng; Xantheas, Sotiris S.

    2010-10-21

    The lowest-energy structures of water clusters (H2O)16 and (H2O)17 were revisited at the MP2 and CCSD(T) levels of theory. A new global minimum structure for (H2O)16 was found at the MP2 and CCSD(T) levels of theory and the effect of zero-point energy corrections on the relative stability of the low-lying minimum energy structures was assessed. For (H2O)17 the CCSD(T) calculations confirm the previously found at the MP2 level of theory "interior" arrangement (fully coordinated water molecule inside a spherical cluster) as the global minimum.

  6. Aquifer-test data for wells H-1, H-2A, H-2B, H-2C, and H-3 at the Waste Isolation Pilot Plant, southeastern New Mexico

    Science.gov (United States)

    Huff, G.F.; Gregory, Angela

    2006-01-01

    A series of aquifer tests was performed by the U.S. Geological Survey on geologic units of Permian age at the Waste Isolation Pilot Plant site between February 1979 and July 1980 in wells H-1, H-2 complex (H-2A, H-2B, and H-2C), and H-3. The tested geologic units included the Magenta Dolomite and Culebra Dolomite Members of the Rustler Formation, and the contact zone between the Rustler and Salado Formations. Selected information on the tested formations, test dates, pre-test static water levels, test configurations, and raw data collected during these tests are tabulated in this report.

  7. An Accurate Potential Energy Surface for H2O

    Science.gov (United States)

    Schwenke, David W.; Partridge, Harry; Langhoff, Stephen R. (Technical Monitor)

    1997-01-01

    We have carried out extensive high quality ab initio electronic structure calculations of the ground state potential energy surface (PES) and dipole moment function (DMF) for H2O. A small adjustment is made to the PES to improve the agreement of line positions from theory and experiment. The theoretical line positions are obtained from variational ro-vibrational calculations using the exact kinetic energy operator. For the lines being fitted, the root-mean-square error was reduced from 6.9 to 0.08 /cm. We were then able to match 30,092 of the 30,117 lines from the HITRAN 96 data base to theoretical lines, and 80% of the line positions differed less than 0.1 /cm. About 3% of the line positions in the experimental data base appear to be incorrect. Theory predicts the existence of many additional weak lines with intensities above the cutoff used in the data base. To obtain results of similar accuracy for HDO, a mass dependent correction to the PH is introduced and is parameterized by simultaneously fitting line positions for HDO and D2O. The mass dependent PH has good predictive value for T2O and HTO. Nonadiabatic effects are not explicitly included. Line strengths for vibrational bands summed over rotational levels usually agree well between theory and experiment, but individual line strengths can differ greatly. A high temperature line list containing about 380 million lines has been generated using the present PES and DMF

  8. Non-BCS thermodynamic properties of H2 S superconductor

    Science.gov (United States)

    Durajski, Artur P.; Szcze&şacute; niak, Radosław; Li, Yinwei

    2015-08-01

    The present paper determines the thermodynamic properties of the superconducting state in the H2S compound. The values of the pressure from 130 GPa to 180 GPa were taken into consideration. The calculations were performed in the framework of the Eliashberg formalism. In the first step, the experimental course of the dependence of the critical temperature on the pressure was reproduced: TC ∈ K, whereas the Coulomb pseudopotential equal to 0.15 was adopted. Next, the following quantities were calculated: the order parameter at the temperature of zero Kelvin (Δ (0)), the specific heat jump at the critical temperature (ΔC (TC) ≡CS (TC) -CN (TC)), and the thermodynamic critical field (HC (0)). It was found that the values of the dimensionless ratios: RΔ ≡ 2 Δ (0) /kBTC , RC ≡ ΔC(TC) /CN (TC) , and RH ≡TCCN (TC) / HC2(0) deviate from the predictions of the BCS theory: RΔ ∈ , RC ∈ , and RH ∈ . Generalizing the results on the whole family of the HnS -type compounds, it was shown that the maximum value of the critical temperature can be equal to ˜290 K, while RΔ,RC and RH adopt the following values: 6.53, 3.99, and 0.093, respectively.

  9. Use of occlusal sealant in a community program and caries incidence in high- and low-risk children

    Directory of Open Access Journals (Sweden)

    Vânia Baldini

    2011-08-01

    Full Text Available OBJECTIVE: The aims of this study were to investigate the effectiveness of sealant placement under the guidelines of the Oral Health Promotion Program for Children and Adolescents (Portugal, and to test the influence of clinical and socioeconomic variables on the DMFT increment in 277 children, born in 1997. MATERIAL AND METHODS: A dental hygienist performed the initial examinations and sealant placement (Helioseal, Vivadent on the permanent first molars in 2005. These activities were registered in dental records that were assessed in 2007. Children were classified according to caries risk at baseline [high (HR: DMFT+dmft>0; low (LR: DMFT+dmft=0 risk] and sealant placement as follows: HR-S and LR-S Groups (with sealant placement; HR-NS and LR-NS Groups (without sealant placement. A calibrated dentist performed the final examination in 2007 at school, based on the World Health Organization recommendations. The variables collected were: dental caries, visible dental plaque, malocclusions, and socioeconomic level (questionnaire sent to children's parents. For univariate (Chi-square or Fisher tests and multivariate (Multiple logistic regression analyses the DMFT increment >0 was selected as dependent variable. RESULTS: Approximately 17.0% of the children showed DMFT increment>0 (mean=0.25. High-risk children presented a significant increase in the number of decayed and/or filled teeth. These children had 7.94 more chance of developing caries. Children who did not receive sealant were 1.8 more prone to have DMFT increment >0. CONCLUSION: It appears that sealant placement was effective in preventing dental caries development. Moreover, the variables "risk" and "sealant placement" were predictors for DMFT increment in the studied children.

  10. Use of occlusal sealant in a community program and caries incidence in high- and low-risk children

    Science.gov (United States)

    BALDINI, Vânia; TAGLIAFERRO, Elaine Pereira da Silva; AMBROSANO, Gláucia Maria Bovi; MENEGHIM, Marcelo de Castro; PEREIRA, Antonio Carlos

    2011-01-01

    Objective The aims of this study were to investigate the effectiveness of sealant placement under the guidelines of the Oral Health Promotion Program for Children and Adolescents (Portugal), and to test the influence of clinical and socioeconomic variables on the DMFT increment in 277 children, born in 1997. Material and Methods A dental hygienist performed the initial examinations and sealant placement (Helioseal, Vivadent) on the permanent first molars in 2005. These activities were registered in dental records that were assessed in 2007. Children were classified according to caries risk at baseline [high (HR: DMFT+dmft>0); low (LR: DMFT+dmft=0) risk] and sealant placement as follows: HR-S and LR-S Groups (with sealant placement); HR-NS and LR-NS Groups (without sealant placement). A calibrated dentist performed the final examination in 2007 at school, based on the World Health Organization recommendations. The variables collected were: dental caries, visible dental plaque, malocclusions, and socioeconomic level (questionnaire sent to children's parents). For univariate (Chi-square or Fisher tests) and multivariate (Multiple logistic regression) analyses the DMFT increment >0 was selected as dependent variable. Results Approximately 17.0% of the children showed DMFT increment>0 (mean=0.25). High-risk children presented a significant increase in the number of decayed and/or filled teeth. These children had 7.94 more chance of developing caries. Children who did not receive sealant were 1.8 more prone to have DMFT increment >0. Conclusion It appears that sealant placement was effective in preventing dental caries development. Moreover, the variables "risk" and "sealant placement" were predictors for DMFT increment in the studied children. PMID:21710092

  11. Investigation of Catalytic Effects and Compositional Variations in Desorption Characteristics of LiNH2-nanoMgH2

    Directory of Open Access Journals (Sweden)

    Sesha S. Srinivasan

    2017-07-01

    Full Text Available LiNH2 and a pre-processed nanoMgH2 with 1:1 and 2:1 molar ratios were mechano-chemically milled in a high-energy planetary ball mill under inert atmosphere, and at room temperature and atmospheric pressure. Based on the thermogravimetric analysis (TGA experiments, 2LiNH2-nanoMgH2 demonstrated superior desorption characteristics when compared to the LiNH2-nanoMgH2. The TGA studies also revealed that doping 2LiNH2-nanoMgH2 base material with 2 wt. % nanoNi catalyst enhances the sorption kinetics at lower temperatures. Additional investigation of different catalysts showed improved reaction kinetics (weight percentage of H2 released per minute of the order TiF3 > nanoNi > nanoTi > nanoCo > nanoFe > multiwall carbon nanotube (MWCNT, and reduction in the on-set decomposition temperatures of the order nanoCo > TiF3 > nanoTi > nanoFe > nanoNi > MWCNT for the base material 2LiNH2-nanoMgH2. Pristine and catalyst-doped 2LiNH2-nanoMgH2 samples were further probed by X-ray diffraction, Fourier transform infrared spectroscopy, transmission and scanning electron microscopies, thermal programmed desorption and pressure-composition-temperature measurements to better understand the improved performance of the catalyst-doped samples, and the results are discussed.

  12. Use of H2(18)O2 to measure absolute rates of dark H2O2 production in freshwater systems.

    Science.gov (United States)

    Vermilyea, Andrew W; Dixon, Taylor C; Voelker, Bettina M

    2010-04-15

    Photochemical production is usually considered to be the main source of H2O2 in freshwater systems; here we show that significant dark production also occurs. We used isotope-labeled H2O2 as a tracer to simultaneously determine H2O2 production and decay rates in incubations of unfiltered water samples. Our new technique for H2(18)O2 analysis, requiring only small sample volumes and simple field equipment, allows for preservation of samples in remote locations, followed by gas chromatography mass spectrometry (GCMS) analysis up to six days later. Dark H2O2 production rates of 29-122 nM/h were observed in several lakewater samples. Measured production and decay rates were consistent with pseudo steady-state, early morning [H2O2] measurements made in each water body. Dark H2O2 production is likely to be more important than photochemical production for the total H2O2 budget over 24 h in the freshwater systems we examined. Our results imply that processes usually assumed to be photochemically induced in freshwaters, such as metal redox cycling mediated by H2O2 and O2(-), and production of strong oxidants from the reaction of H2O2 with Fe(II) (Fenton's reaction) could also be occurring at significant rates in the absence of light.

  13. Catalase activity is stimulated by H2O2 in rich culture medium and is required for H2O2 resistance and adaptation in yeast

    Directory of Open Access Journals (Sweden)

    Dorival Martins

    2014-01-01

    Full Text Available Catalases are efficient scavengers of H2O2 and protect cells against H2O2 stress. Examination of the H2O2 stimulon in Saccharomyces cerevisiae revealed that the cytosolic catalase T (Ctt1 protein level increases 15-fold on H2O2 challenge in synthetic complete media although previous work revealed that deletion of the CCT1 or CTA1 genes (encoding peroxisomal/mitochondrial catalase A does not increase the H2O2 sensitivity of yeast challenged in phosphate buffer (pH 7.4. This we attributed to our observation that catalase activity is depressed when yeast are challenged with H2O2 in nutrient-poor media. Hence, we performed a systematic comparison of catalase activity and cell viability of wild-type yeast and of the single catalase knockouts, ctt1∆ and cta1∆, following H2O2 challenge in nutrient-rich medium (YPD and in phosphate buffer (pH 7.4. Ctt1 but not Cta1 activity is strongly induced by H2O2 when cells are challenged in YPD but suppressed when cells are challenged in buffer. Consistent with the activity results, exponentially growing ctt1∆ cells in YPD are more sensitive to H2O2 than wild-type or cta1∆ cells, whereas in buffer all three strains exhibit comparable H2O2 hypersensitivity. Furthermore, catalase activity is increased during adaptation to sublethal H2O2 concentrations in YPD but not in buffer. We conclude that induction of cytosolic Ctt1 activity is vital in protecting yeast against exogenous H2O2 but this activity is inhibited by H2O2 when cells are challenged in nutrient-free media.

  14. Catalase activity is stimulated by H2O2 in rich culture medium and is required for H2O2 resistance and adaptation in yeast☆

    Science.gov (United States)

    Martins, Dorival; English, Ann M.

    2014-01-01

    Catalases are efficient scavengers of H2O2 and protect cells against H2O2 stress. Examination of the H2O2 stimulon in Saccharomyces cerevisiae revealed that the cytosolic catalase T (Ctt1) protein level increases 15-fold on H2O2 challenge in synthetic complete media although previous work revealed that deletion of the CCT1 or CTA1 genes (encoding peroxisomal/mitochondrial catalase A) does not increase the H2O2 sensitivity of yeast challenged in phosphate buffer (pH 7.4). This we attributed to our observation that catalase activity is depressed when yeast are challenged with H2O2 in nutrient-poor media. Hence, we performed a systematic comparison of catalase activity and cell viability of wild-type yeast and of the single catalase knockouts, ctt1∆ and cta1∆, following H2O2 challenge in nutrient-rich medium (YPD) and in phosphate buffer (pH 7.4). Ctt1 but not Cta1 activity is strongly induced by H2O2 when cells are challenged in YPD but suppressed when cells are challenged in buffer. Consistent with the activity results, exponentially growing ctt1∆ cells in YPD are more sensitive to H2O2 than wild-type or cta1∆ cells, whereas in buffer all three strains exhibit comparable H2O2 hypersensitivity. Furthermore, catalase activity is increased during adaptation to sublethal H2O2 concentrations in YPD but not in buffer. We conclude that induction of cytosolic Ctt1 activity is vital in protecting yeast against exogenous H2O2 but this activity is inhibited by H2O2 when cells are challenged in nutrient-free media. PMID:24563848

  15. Catalase activity is stimulated by H(2)O(2) in rich culture medium and is required for H(2)O(2) resistance and adaptation in yeast.

    Science.gov (United States)

    Martins, Dorival; English, Ann M

    2014-01-01

    Catalases are efficient scavengers of H2O2 and protect cells against H2O2 stress. Examination of the H2O2 stimulon in Saccharomyces cerevisiae revealed that the cytosolic catalase T (Ctt1) protein level increases 15-fold on H2O2 challenge in synthetic complete media although previous work revealed that deletion of the CCT1 or CTA1 genes (encoding peroxisomal/mitochondrial catalase A) does not increase the H2O2 sensitivity of yeast challenged in phosphate buffer (pH 7.4). This we attributed to our observation that catalase activity is depressed when yeast are challenged with H2O2 in nutrient-poor media. Hence, we performed a systematic comparison of catalase activity and cell viability of wild-type yeast and of the single catalase knockouts, ctt1∆ and cta1∆, following H2O2 challenge in nutrient-rich medium (YPD) and in phosphate buffer (pH 7.4). Ctt1 but not Cta1 activity is strongly induced by H2O2 when cells are challenged in YPD but suppressed when cells are challenged in buffer. Consistent with the activity results, exponentially growing ctt1∆ cells in YPD are more sensitive to H2O2 than wild-type or cta1∆ cells, whereas in buffer all three strains exhibit comparable H2O2 hypersensitivity. Furthermore, catalase activity is increased during adaptation to sublethal H2O2 concentrations in YPD but not in buffer. We conclude that induction of cytosolic Ctt1 activity is vital in protecting yeast against exogenous H2O2 but this activity is inhibited by H2O2 when cells are challenged in nutrient-free media.

  16. TLR agonists downregulate H2-O in CD8α− DCs1

    Science.gov (United States)

    Porter, Gavin W.; Yi, Woelsung; Denzin, Lisa K.

    2011-01-01

    Peptide loading of MHC class II (MHCII) molecules is catalyzed by the non-classical MHCII-related molecule, H2-M. H2-O, another MHCII-like molecule, associates with H2-M and modulates H2-M function. The MHCII presentation pathway is tightly regulated in dendritic cells (DCs); yet how the key modulators of MHCII presentation, H2-M and H2-O, are affected in different DC subsets in response to maturation is unknown. Here we show that H2-O is markedly downregulated in vivo in mouse CD8α− DCs in response to a broad array of TLR agonists. In contrast, CD8α+ DCs only modestly downregulated H2-O in response to TLR-agonists. H2-M levels were slightly down-modulated in both CD8α− and CD8α+ DCs. As a consequence, H2-M:H2-O ratios significantly increased for CD8α− but not CD8α+ DCs. The TLR-mediated downregulation was DC-specific, as B cells did not show significant H2-O and H2-M downregulation. TLR4 signaling was required to mediate DC H2-O downregulation in response to LPS. Finally, our studies showed that the mechanism of H2-O downregulation was likely due to direct protein degradation of H2-O as well as down regulation of H2-O mRNA levels. The differential H2-O and H2-M modulation after DC maturation support the proposed roles of CD8α− dendritic cells in initiating CD4-restricted immune responses by optimal MHCII presentation and CD8α+ DCs in promoting immune tolerance via presentation of low levels of MHCII-peptide. PMID:21918198

  17. TLR agonists downregulate H2-O in CD8alpha- dendritic cells.

    Science.gov (United States)

    Porter, Gavin W; Yi, Woelsung; Denzin, Lisa K

    2011-10-15

    Peptide loading of MHC class II (MHCII) molecules is catalyzed by the nonclassical MHCII-related molecule H2-M. H2-O, another MHCII-like molecule, associates with H2-M and modulates H2-M function. The MHCII presentation pathway is tightly regulated in dendritic cells (DCs), yet how the key modulators of MHCII presentation, H2-M and H2-O, are affected in different DC subsets in response to maturation is unknown. In this study, we show that H2-O is markedly downregulated in vivo in mouse CD8α(-) DCs in response to a broad array of TLR agonists. In contrast, CD8α(+) DCs only modestly downregulated H2-O in response to TLR agonists. H2-M levels were slightly downmodulated in both CD8α(-) and CD8α(+) DCs. As a consequence, H2-M/H2-O ratios significantly increased for CD8α(-) but not for CD8α(+) DCs. The TLR-mediated downregulation was DC specific, as B cells did not show significant H2-O and H2-M downregulation. TLR4 signaling was required to mediate DC H2-O downregulation in response to LPS. Finally, our studies showed that the mechanism of H2-O downregulation was likely due to direct protein degradation of H2-O as well as downregulation of H2-O mRNA levels. The differential H2-O and H2-M modulation after DC maturation supports the proposed roles of CD8α(-) DCs in initiating CD4-restricted immune responses by optimal MHCII presentation and of CD8α(+) DCs in promoting immune tolerance via presentation of low levels of MHCII-peptide.

  18. Catalytically Enhanced Hydrogen Sorption in Mg-MgH2 by Coupling Vanadium-Based Catalyst and Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Atikah Kadri

    2015-06-01

    Full Text Available Mg (MgH2-based composites, using carbon nanotubes (CNTs and pre-synthesized vanadium-based complex (VCat as the catalysts, were prepared by high-energy ball milling technique. The synergistic effect of coupling CNTs and VCat in MgH2 was observed for an ultra-fast absorption rate of 6.50 wt. % of hydrogen per minute and 6.50 wt. % of hydrogen release in 10 min at 200 °C and 300 °C, respectively. The temperature programmed desorption (TPD results reveal that coupling VCat and CNTs reduces both peak and onset temperatures by more than 60 °C and 114 °C, respectively. In addition, the presence of both VCat and CNTs reduces the enthalpy and entropy of desorption of about 7 kJ/mol H2 and 11 J/mol H2·K, respectively, as compared to those of the commercial MgH2, which ascribe to the decrease of desorption temperature. From the study of the effect of CNTs milling time, it is shown that partially destroyed CNTs (shorter milling time are better to enhance the hydrogen sorption performance.

  19. Molecular analysis of an EL4 cell line that expresses H-2Db but not H-2Kb or beta 2-microglobulin.

    Science.gov (United States)

    Potter, T A; Zeff, R A; Schmitt-Verhulst, A M; Rajan, T V

    1985-01-01

    EL4/Mar is a variant cell line that expresses H-2Db but neither H-2Kb nor beta 2-microglobulin (beta 2m). Southern and RNA blot analysis and immunoprecipitation of metabolically labeled proteins established that the B2m gene(s), beta 2m mRNA, and beta 2m protein are normal in this cell line. Somatic cell hybridization showed that the defect in this cell line was in the synthesis of H-2Kb, and RNA blot analysis with an H-2Kb specific oligonucleotide established that the H-2Kb gene(s) in this cell line was not transcribed into a stable mRNA species. The apparent absence of beta 2m on the surface of this cell line suggests that there may be some feature of the H-2Db molecule that allows it to be expressed in the absence of detectable beta 2m. Images PMID:3887412

  20. A thermodynamic study of 1-propanol-glycerol-H2O at 25 degrees C: Effect of glycerol on molecular organization of H2O

    DEFF Research Database (Denmark)

    Parsons, M.T.; Westh, Peter; Davies, J.V.

    2001-01-01

    of H2O. The glycerol molecules do not exert a hydrophobic effect on H2O. Rather, the hydroxyl groups of glycerol, perhaps by forming clusters via its alkyl backbone with hydroxyl groups pointing outward, interact with H2O so as to reduce the characteristics of liquid H2O. The global hydrogen bond......The excess chemical potential, partial molar enthalpy, and volume of 1-propanol were determined in ternary mixtures of 1-propanol-glycerol-H2O at 25degreesC. The mole fraction dependence of all these thermodynamic functions was used to elucidate the effect of glycerol on the molecular organization...... probability and, hence, the percolation nature of the hydrogen bond network is reduced. In addition, the degree of fluctuation inherent in liquid H2O is reduced by glycerol perhaps by participating in the hydrogen bond network via OH groups. At infinite dilution, the pair interaction coefficients in enthalpy...

  1. Localization and expression of histone H2A variants during mouse oogenesis and preimplantation embryo development.

    Science.gov (United States)

    Wu, B J; Dong, F L; Ma, X S; Wang, X G; Lin, F; Liu, H L

    2014-08-07

    Epigenetic modifications of the genome, such as histone H2A variants, ensure appropriate gene activation or silencing during oogenesis and preimplantation embryo development. We examined global localization and expression of the histone H2A variants, including H2A.Bbd, H2A.Z and H2A.X, during mouse oogenesis and preimplantation embryo development. Immunocytochemistry with specific antibodies against various histone H2A variants showed their localization and changes during oogenesis and preimplantation development. H2A.Bbd and H2A.Z were almost absent from nuclei of growing oocytes (except 5-day oocyte), whereas H2A.X was deposited in nuclei throughout oogenesis and in preimplantation embryos. In germinal vesicle (GV) oocyte chromatin, H2A.Bbd was detected as a weak signal, whereas no fluorescent signal was detected in GV breakdown (GVBD) or metaphase II (MII) oocytes; H2A.Z showed intense signals in chromatin of GV, GVBD and MII oocytes. H2A. Bbd showed very weak signals in both pronucleus and 2-cell embryo nuclei, but intense signals were detected in nuclei from 4-cell embryo to blastula. The H2A.Z signal was absent from pronucleus to morula chromatin, whereas a fluorescent signal was detected in blastula nuclei. Our results suggest that histone H2A variants are probably involved in reprogramming of genomes during oocyte meiosis or after fertilization.

  2. SULFUR CHEMISTRY IN THE INTERSTELLAR MEDIUM: THE EFFECT OF VIBRATIONAL EXCITATION OF H-2 IN THE REACTION S++ H-2 -> SH++ H

    OpenAIRE

    Aguado. A.; Roncero O.; Zanchet A.; Herrero V.J.; Agundez M.

    2016-01-01

    The Astrophysical Journal 146.5 (2013): 125, reproduced by permission of the AAS Specific rate constants for the S++H2 reaction are calculated using the ground quartet state potential energy surface and quasi-classical trajectories method. The calculations are performed for H 2 in different vibrational states v = 0-4 and thermal conditions for rotational and translational energies. The calculations lead to slow rate constants for the H2 vibrational levels v = 0, 1, but a significant enhanc...

  3. The study on single crystal structure of [Zn(Hpdc) 2(H 2O) 2]·2H 2O (Hpdc -=2,5-pyridinedicarboxylic acid group)

    Science.gov (United States)

    Haitao, Xu; Nengwu, Zheng; Hanhui, Xu; Yonggang, Wu; Ruyi, Yang; Enyi, Ye; Xianglin, Jin

    2001-10-01

    The hydrothermal synthesis and structure of a coordination polymer Zn(Hpdc)2(H2O)2]·2H2O were reported. The Zn2+ center was coordinated by two waters and two chelated Hpdc- to form units [Zn(Hpdc)2 (H2O)2] and the units were connected by hydrogen bonds to engender one-dimensional channels through the c axis. Especially, the two lattice waters play an important role in construction of these channels.

  4. Incidence, Risk Factors, and Trends of Motor Peripheral Nerve Injury After Colorectal Surgery: Analysis of the National Surgical Quality Improvement Program Database.

    Science.gov (United States)

    Al-Temimi, Mohammed H; Chandrasekaran, Bindupriya; Phelan, Michael J; Pigazzi, Alessio; Mills, Steven D; Stamos, Michael J; Carmichael, Joseph C

    2017-03-01

    Motor peripheral nerve injury is a rare but serious event after colorectal surgery, and a nationwide study of this complication is lacking. The purpose of this study was to report the incidence, trends, and risk factors of motor peripheral nerve injury during colorectal surgery. The National Surgical Quality Improvement Program database was surveyed for motor peripheral nerve injury complicating colorectal procedures. Risk factors for this complication were identified using logistic regression analysis. The study used a national database. Patients undergoing colorectal resection between 2005 and 2013 were included. The incidence, trends, and risk factors for motor peripheral nerve injury complicating colorectal procedures were measured. We identified 186,936 colorectal cases, of which 50,470 (27%) were performed laparoscopically. Motor peripheral nerve injury occurred in 122 patients (0.065%). Injury rates declined over the study period, from 0.025% in 2006 to peripheral nerve injury were younger (mean ± SD; 54.02 ± 15.41 y vs 61.56 ± 15.95 y; p injury was also associated with longer operative times (277.16 ± 169.79 min vs 176.69 ± 104.80 min; p injury (OR = 1.04 (95% CI, 1.03-1.04)), whereas increasing age was associated with a protective effect (OR = 0.80 (95% CI, 0.71-0.90)). This study was limited by its retrospective nature. Motor peripheral nerve injury during colorectal procedures is uncommon (0.065%), and its rate declined significantly over the study period. Prolonged operative time is the strongest predictor of motor peripheral nerve injury during colorectal procedures. Instituting and documenting measures to prevent nerve injury is imperative; however, special attention to this complication is necessary when surgeons contemplate long colorectal procedures.

  5. The incidence and persistence of the NCEP (National Cholesterol Education Program) metabolic syndrome. The French D.E.S.I.R. study.

    Science.gov (United States)

    Balkau, B; Vernay, M; Mhamdi, L; Novak, M; Arondel, D; Vol, S; Tichet, J; Eschwège, E

    2003-11-01

    In 2001 the "National Cholesterol and Education Program Expert Panel" gave a clinical definition of the metabolic syndrome. The frequency of this syndrome at baseline and its incidence and persistence at three years is studied in a French population. 2109 men and 2184 women from the D.E.S.I.R. longitudinal cohort study (Data from an Epidemiological Study on the Insulin Resistance syndrome) in central-western France, aged 30 to 64 years, were examined at inclusion and three years later. Evaluation of the frequencies, incidences and persistence of the metabolic syndrome and its abnormalities. This syndrome is defined by the presence of three or more of five abnormalities: waist circumference > 102/88 cm (men/women); triglycerides > o r=1.69 mmol/l, HDL-cholesterolwomen); systolic/diastolic blood pressure > or =130 and/or 85 mmHg; fasting plasma glucose > or =6.1 mmol/l. At baseline, 10% of men and 7% of women had the metabolic syndrome. If the syndrome was defined to include a treatment in the abnormalities (for diabetes, hypertension, dyslipidemia), the syndrome frequencies increased to 16% and 11%. However only 12% and 8% respectively, had this syndrome both at inclusion and at three years. High blood pressure was the most frequent abnormality: 70% and 47% in men and women respectively, at inclusion. The most stable abnormality was high waist circumference (80% persisted), hyperglycaemia the least stable (60% persisted). Hyperinsulinaemia did not cluster closely with this syndrome. The age-specific frequency of the syndrome is more than 2.5 times higher in the US than in this French cohort and this ratio increased with age. The higher frequencies of abdominal obesity and low HDL-cholesterol in women than in men suggest that these gender-specific thresholds may need to be refined.

  6. Stable solid and aqueous H2CO3 from CO2 and H2O at high pressure and high temperature

    Science.gov (United States)

    Wang, Hongbo; Zeuschner, Janek; Eremets, Mikhail; Troyan, Ivan; Willams, Jonathan

    2016-01-01

    Carbonic acid (H2CO3) forms in small amounts when CO2 dissolves in H2O, yet decomposes rapidly under ambient conditions of temperature and pressure. Despite its fleeting existence, H2CO3 plays an important role in the global carbon cycle and in biological carbonate-containing systems. The short lifetime in water and presumed low concentration under all terrestrial conditions has stifled study of this fundamental species. Here, we have examined CO2/H2O mixtures under conditions of high pressure and high temperature to explore the potential for reaction to H2CO3 inside celestial bodies. We present a novel method to prepare solid H2CO3 by heating CO2/H2O mixtures at high pressure with a CO2 laser. Furthermore, we found that, contrary to present understanding, neutral H2CO3 is a significant component in aqueous CO2 solutions above 2.4 GPa and 110 °C as identified by IR-absorption and Raman spectroscopy. This is highly significant for speciation of deep C-O-H fluids with potential consequences for fluid-carbonate-bearing rock interactions. As conditions inside subduction zones on Earth appear to be most favorable for production of aqueous H2CO3, a role in subduction related phenomena is inferred.

  7. A neural network potential energy surface for the NaH2 system and dynamics studies on the H(2S) + NaH(X1Σ+) → Na(2S) + H2(X1Σg+) reaction.

    Science.gov (United States)

    Wang, Shufen; Yuan, Jiuchuang; Li, Huixing; Chen, Maodu

    2017-08-02

    In order to study the dynamics of the reaction H(2S) + NaH(X1Σ+) → Na(2S) + H2(X1Σg+), a new potential energy surface (PES) for the ground state of the NaH2 system is constructed based on 35 730 ab initio energy points. Using basis sets of quadruple zeta quality, multireference configuration interaction calculations with Davidson correction were carried out to obtain the ab initio energy points. The neural network method is used to fit the PES, and the root mean square error is very small (0.00639 eV). The bond lengths, dissociation energies, zero-point energies and spectroscopic constants of H2(X1Σg+) and NaH(X1Σ+) obtained on the new NaH2 PES are in good agreement with the experiment data. On the new PES, the reactant coordinate-based time-dependent wave packet method is applied to study the reaction dynamics of H(2S) + NaH(X1Σ+) → Na(2S) + H2(X1Σg+), and the reaction probabilities, integral cross-sections (ICSs) and differential cross-sections (DCSs) are obtained. There is no threshold in the reaction due to the absence of an energy barrier on the minimum energy path. When the collision energy increases, the ICSs decrease from a high value at low collision energy. The DCS results show that the angular distribution of the product molecules tends to the forward direction. Compared with the LiH2 system, the NaH2 system has a larger mass and the PES has a larger well at the H-NaH configuration, which leads to a higher ICS value in the H(2S) + NaH(X1Σ+) → Na(2S) + H2(X1Σg+) reaction. Because the H(2S) + NaH(X1Σ+) → Na(2S) + H2(X1Σg+) reaction releases more energy, the product molecules can be excited to a higher vibrational state.

  8. H2Ti3O7 Nanotubes Decorated with Silver Nanoparticles for Photocatalytic Degradation of Atenolol

    Directory of Open Access Journals (Sweden)

    Mariana Hinojosa-Reyes

    2017-01-01

    Full Text Available The photocatalytic degradation/adsorption process of the β-blocker atenolol (ATL under UV irradiation is described using two types of silver decorated catalysts: silver/titania and silver/titanates. The silver ions were reduced on the surface of TiO2-P25-Degussa using gallic acid. Silver/titanates were prepared by a microwave-assisted hydrothermal method using the silver/titania as the starting material to obtain the hydrogen titanate (H2Ti3O7 structure with tubular morphology. These materials were characterized by X-ray diffraction, UV-Vis spectroscopy, N2 physisorption, temperature programmed reduction, TEM, and FTIR spectroscopy. During the photocatalytic process, the ATL molecules were completely converted to amino-diol byproducts. It is the first time that these materials have been applied during the photocatalytic process in the degradation of pharmaceuticals products. The success of the silver nanoparticles (2 nm consists of the homogeneous distribution over the surface of titanate nanotubes inhibiting the hole/electron recombination promoting the oxidation process. The Ag@H2Ti3O7 with a concentration of silver as 1.0% shows the highest adsorption/degradation of ATL than the Ag@TiO2 and the P25-Degussa. The great performance in the reuse test consists in the strong attachment of the silver nanoparticles on the titanium surface that inhibits the silver lixiviation during the photocatalytic tests.

  9. Phylogenomics of unusual histone H2A Variants in Bdelloid rotifers.

    Science.gov (United States)

    Van Doninck, Karine; Mandigo, Morgan L; Hur, Jae H; Wang, Peter; Guglielmini, Julien; Milinkovitch, Michel C; Lane, William S; Meselson, Matthew

    2009-03-01

    Rotifers of Class Bdelloidea are remarkable in having evolved for millions of years, apparently without males and meiosis. In addition, they are unusually resistant to desiccation and ionizing radiation and are able to repair hundreds of radiation-induced DNA double-strand breaks per genome with little effect on viability or reproduction. Because specific histone H2A variants are involved in DSB repair and certain meiotic processes in other eukaryotes, we investigated the histone H2A genes and proteins of two bdelloid species. Genomic libraries were built and probed to identify histone H2A genes in Adineta vaga and Philodina roseola, species representing two different bdelloid families. The expressed H2A proteins were visualized on SDS-PAGE gels and identified by tandem mass spectrometry. We find that neither the core histone H2A, present in nearly all other eukaryotes, nor the H2AX variant, a ubiquitous component of the eukaryotic DSB repair machinery, are present in bdelloid rotifers. Instead, they are replaced by unusual histone H2A variants of higher mass. In contrast, a species of rotifer belonging to the facultatively sexual, desiccation- and radiation-intolerant sister class of bdelloid rotifers, the monogononts, contains a canonical core histone H2A and appears to lack the bdelloid H2A variant genes. Applying phylogenetic tools, we demonstrate that the bdelloid-specific H2A variants arose as distinct lineages from canonical H2A separate from those leading to the H2AX and H2AZ variants. The replacement of core H2A and H2AX in bdelloid rotifers by previously uncharacterized H2A variants with extended carboxy-terminal tails is further evidence for evolutionary diversity within this class of histone H2A genes and may represent adaptation to unusual features specific to bdelloid rotifers.

  10. NK Cell Receptor/H2-Dk–Dependent Host Resistance to Viral Infection Is Quantitatively Modulated by H2 q Inhibitory Signals

    Science.gov (United States)

    Fodil-Cornu, Nassima; Loredo-Osti, J. Concepción; Vidal, Silvia M.

    2011-01-01

    The cytomegalovirus resistance locus Cmv3 has been linked to an epistatic interaction between two loci: a Natural Killer (NK) cell receptor gene and the major histocompatibility complex class I (MHC-I) locus. To demonstrate the interaction between Cmv3 and H2k, we generated double congenic mice between MA/My and BALB.K mice and an F2 cross between FVB/N (H-2q) and BALB.K (H2k) mice, two strains susceptible to mouse cytomegalovirus (MCMV). Only mice expressing H2k in conjunction with Cmv3MA/My or Cmv3FVB were resistant to MCMV infection. Subsequently, an F3 cross was carried out between transgenic FVB/H2-Dk and MHC-I deficient mice in which only the progeny expressing Cmv3FVB and a single H2-Dk class-I molecule completely controlled MCMV viral loads. This phenotype was shown to be NK cell–dependent and associated with subsequent NK cell proliferation. Finally, we demonstrated that a number of H2q alleles influence the expression level of H2q molecules, but not intrinsic functional properties of NK cells; viral loads, however, were quantitatively proportional to the number of H2q alleles. Our results support a model in which H-2q molecules convey Ly49-dependent inhibitory signals that interfere with the action of H2-Dk on NK cell activation against MCMV infection. Thus, the integration of activating and inhibitory signals emanating from various MHC-I/NK cell receptor interactions regulates NK cell–mediated control of viral load. PMID:21533075

  11. NK cell receptor/H2-Dk-dependent host resistance to viral infection is quantitatively modulated by H2q inhibitory signals.

    Science.gov (United States)

    Fodil-Cornu, Nassima; Loredo-Osti, J Concepción; Vidal, Silvia M

    2011-04-01

    The cytomegalovirus resistance locus Cmv3 has been linked to an epistatic interaction between two loci: a Natural Killer (NK) cell receptor gene and the major histocompatibility complex class I (MHC-I) locus. To demonstrate the interaction between Cmv3 and H2(k), we generated double congenic mice between MA/My and BALB.K mice and an F(2) cross between FVB/N (H-2(q)) and BALB.K (H2(k)) mice, two strains susceptible to mouse cytomegalovirus (MCMV). Only mice expressing H2(k) in conjunction with Cmv3(MA/My) or Cmv3(FVB) were resistant to MCMV infection. Subsequently, an F(3) cross was carried out between transgenic FVB/H2-D(k) and MHC-I deficient mice in which only the progeny expressing Cmv3(FVB) and a single H2-D(k) class-I molecule completely controlled MCMV viral loads. This phenotype was shown to be NK cell-dependent and associated with subsequent NK cell proliferation. Finally, we demonstrated that a number of H2(q) alleles influence the expression level of H2(q) molecules, but not intrinsic functional properties of NK cells; viral loads, however, were quantitatively proportional to the number of H2(q) alleles. Our results support a model in which H-2(q) molecules convey Ly49-dependent inhibitory signals that interfere with the action of H2-D(k) on NK cell activation against MCMV infection. Thus, the integration of activating and inhibitory signals emanating from various MHC-I/NK cell receptor interactions regulates NK cell-mediated control of viral load.

  12. Decapado del acero inoxidable AISI 316L utilizando una mezcla ecológica de H2O2-H2SO4-HF

    Directory of Open Access Journals (Sweden)

    Gómez, P. P.

    2005-12-01

    Full Text Available This study reports the pickling of austenitic AISI 316L stainless steel (SS using a mixture of hydrogen peroxide (H2O2, sulphuric acid (H2SO4 and hydrofluoric acid (HF at pH 2.0. The stability of H2O2 was also studied using different concentrations of ferric ion from 0 to 40 g/l and temperature from 25 to 60 °C. The pickling rate at 50 °C in the presence and absence of 40 g/l ferric ion was 2.6 and 0.2 mg/dm2 day (mdd, respectively. p-Toluene sulphonic acid was used as stabilizer of H2O2.En la presente investigación se estudia el decapado del acero inoxidable AISI 316L utilizando una mezcla de agua oxigenada (H2O2 y los ácidos sulfúrico (H2SO4 y fluorhídrico (HF a pH 2,0. La estabilidad de la mezcla H2O2-H2SO4-HF se ha ensayado variando el contenido de iones férrico de O a 40 g/l y la temperatura de 25 a 60 °C. La velocidad de decapado a 50 °C ha sido de 2,6 y 0,2 mg/dm2 día (mdd, en ausencia y presencia de 40 g/l de iones férrico, respectivamente. Se ha utilizado el ácido p-toluen sulfónico como estabilizante del H2O2.

  13. I + (H2O)2 → HI + (H2O)OH Forward and Reverse Reactions. CCSD(T) Studies Including Spin-Orbit Coupling.

    Science.gov (United States)

    Wang, Hui; Li, Guoliang; Li, Qian-Shu; Xie, Yaoming; Schaefer, Henry F

    2016-03-03

    The potential energy profile for the atomic iodine plus water dimer reaction I + (H2O)2 → HI + (H2O)OH has been explored using the "Gold Standard" CCSD(T) method with quadruple-ζ correlation-consistent basis sets. The corresponding information for the reverse reaction HI + (H2O)OH → I + (H2O)2 is also derived. Both zero-point vibrational energies (ZPVEs) and spin-orbit (SO) coupling are considered, and these notably alter the classical energetics. On the basis of the CCSD(T)/cc-pVQZ-PP results, including ZPVE and SO coupling, the forward reaction is found to be endothermic by 47.4 kcal/mol, implying a significant exothermicity for the reverse reaction. The entrance complex I···(H2O)2 is bound by 1.8 kcal/mol, and this dissociation energy is significantly affected by SO coupling. The reaction barrier lies 45.1 kcal/mol higher than the reactants. The exit complex HI···(H2O)OH is bound by 3.0 kcal/mol relative to the asymptotic limit. At every level of theory, the reverse reaction HI + (H2O)OH → I + (H2O)2 proceeds without a barrier. Compared with the analogous water monomer reaction I + H2O → HI + OH, the additional water molecule reduces the relative energies of the entrance stationary point, transition state, and exit complex by 3-5 kcal/mol. The I + (H2O)2 reaction is related to the valence isoelectronic bromine and chlorine reactions but is distinctly different from the F + (H2O)2 system.

  14. Formation of H2O+ and H3O+ Cations in Reactions of OH+ and H2O+ with H2: Experimental Studies of the Reaction Rate Coefficients from T = 15 to 300 K

    Science.gov (United States)

    Dung Tran, Thuy; Rednyk, Serhiy; Kovalenko, Artem; Roučka, Štěpán; Dohnal, Petr; Plašil, Radek; Gerlich, Dieter; Glosík, Juraj

    2018-02-01

    {{OH}}+ and {{{H}}}2{{{O}}}+ cations play a significant role in the chemistry of the cold interstellar medium and hence their hydrogen abstraction reactions with {{{H}}}2 have to be included in ion chemical models. The reactions lead directly or indirectly to {{{H}}}3{{{O}}}+ ions that subsequently recombine with electrons and dissociate into H atoms and {{{H}}}2{{O}}. The experiments described in this paper provide rate coefficients ({k}{{OH}+} and {k}{{{H}}2{{{O}}}+}) for the reactions of {{OH}}+ and {{{H}}}2{{{O}}}+ with {{{H}}}2 over a wide temperature range (from 15 to 300 K). A cryogenic 22-pole RF ion trap instrument was employed for this purpose. It was found that {k}{{OH}+} increases from (0.76+/- 0.30)× {10}-9 {{cm}}3 {{{s}}}-1 at 17 K to (1.24+/- 0.25)× {10}-9 {{cm}}3 {{{s}}}-1 at 263 K while {k}{{{H}}2{{{O}}}+} is nearly constant, varying from (0.93+/- 0.35) × {10}-9 {{cm}}3 {{{s}}}-1 at 17 K to (1.00+/- 0.25)× {10}-9 {{cm}}3 {{{s}}}-1 at 218 K.

  15. A SAFT Equation of State for the H2S-CO2-H2O-NaCl system and applications for CO2 - H2S transportation and geological storage

    OpenAIRE

    Ji, Xiaoyan; Zhu, Chen

    2013-01-01

    When H2S is co-injected with CO2, we need to know thermodynamic properties and phase equilibria for the CO2-H2S- H2O-NaCl system in order to evaluate the sequestration capacity, optimal transportation and injection conditions, potential for pipeline corrosion, and increased risk of storage and leakage. Here, we summarize the results of the phase equilibrium and densities for CO2-sequestration related systems from a thermodynamic model that is based on statistical associating fluid theory equa...

  16. A SAFT equation of state for the quaternary H2S-CO2-H2O-NaCl system

    Science.gov (United States)

    Ji, Xiaoyan; Zhu, Chen

    2012-08-01

    Phase equilibria and thermodynamic properties of the quaternary H2S-CO2-H2O-NaCl system were studied using a statistical associating fluid theory (SAFT)-based equation of state (EOS) at temperatures from 0 to 200 °C (373.15-473.15 K), pressures up to 600 bar (60 MPa) and concentrations of NaCl up to 6 mol/kgH2O. The understanding of the physical-chemical properties of this system is critical for predicting the consequences of co-injection of CO2 and H2S into geological formations (geological carbon sequestration) as an option for mitigating the global warming trend. Equation of state parameters were generated from regression of available and reliable experimental data and incorporation of existing parameters for some subsystems. Densities were predicted and compared with available experimental results. Using the EOS developed in this study, we predicted equilibrium compositions in both liquid and vapor phases, fugacity coefficients of components, the equilibrium pressures at a given composition of the H2O-rich phase in electrolyte solutions with NaCl varying from 0 to 4 mol/kgH2O, and the aqueous solution densities. These predicted values are tabulated and available as supplementary data in the electronic version online. These predictions provide information and guidance for future experiments regarding the thermodynamic properties and phase behaviors in the H2S-CO2-H2O-NaCl system.

  17. Nanoparticle formation in H2O/N-2 and H2O/Ar mixtures under irradiation by 20 MeV protons and positive corona discharge

    DEFF Research Database (Denmark)

    Imanaka, M.; Tomita, S.; Kanda, S.

    2010-01-01

    To investigate the contribution of ions to gas nucleation, we have performed experiments on the formation of water droplets in H2O/N-2 and H2O/Ar gas mixtures by irradiation with a 20 MeV proton beam and by positive corona discharge. The size of the formed nanoparticles was measured using a diffe...

  18. Molecular hydrogen (H2) emissions and their isotopic signatures (H/D) from a motor vehicle : implications on atmospheric H2

    NARCIS (Netherlands)

    Vollmer, M.K.; Walter, S.; Bond, S.W.; Soltic, P.; Röckmann, T.

    2010-01-01

    Molecular hydrogen (H2), its isotopic signature (deuterium/hydrogen, δD), carbon monoxide (CO) and other compounds were studied in the exhaust of a passenger car engine fuelled with gasoline or methane and run under variable air-fuel ratios and operating modes. H2 and CO concentrations were largely

  19. Soil carbon content and relative abundance of high affinity H2-oxidizing bacteria predict atmospheric H2 soil uptake activity better than soil microbial community composition

    NARCIS (Netherlands)

    Khdhiri, Mondher; Hesse, Laura; Popa, Maria Elena; Quiza, Liliana; Lalonde, Isabelle; Meredith, Laura K.; Röckmann, Thomas; Constant, Philippe

    2015-01-01

    Soil-atmosphere exchange of H2 is controlled by gas diffusion and the microbial production and oxidation activities in soil. Among these parameters, the H2 oxidation activity catalyzed by soil microorganisms harboring high affinity hydrogenase is the most difficult variable to parameterize because

  20. Decolorization and Mineralization of Reactive Dyes, by the H2O2/UV Process With Electrochemically Produced H2O2

    NARCIS (Netherlands)

    Jeric, T.; Bisselink, R.J.M.; Tongeren, W. van; Marechal. A.M. Le

    2013-01-01

    Decolorization of Reactive Red 238, Reactive Orange 16, Reactive Black 5 and Reactive Blue 4 was studied in the UV/H2O2 process with H2O2 being produced electrochemically. The experimental results show that decolorization increased considerably when switching on the electrochemical production of

  1. Self-sufficing H2O2-responsive nanocarriers through tumor-specific H2O2 production for synergistic oxidation-chemotherapy.

    Science.gov (United States)

    Li, Junjie; Ke, Wendong; Wang, Lei; Huang, Mingming; Yin, Wei; Zhang, Ping; Chen, Qixian; Ge, Zhishen

    2016-03-10

    One of distinct features in tumor tissues is the elevated concentration of reactive oxygen species (ROS) during tumor immortality, proliferation and metastasis. However, ROS-responsive materials are rarely utilized in the field of in vivo tumoral ROS-responsive applications due to the fact that the intrinsic ROS level in the tumors could not escalate to an adequate level that the developed materials can possibly respond. Herein, palmitoyl ascorbate (PA) as a prooxidant for hydrogen peroxide (H2O2) production in tumor tissue is strategically compiled into a H2O2-responsive camptothecin (CPT) polymer prodrug micelle, which endowed the nanocarriers with self-sufficing H2O2 stimuli in tumor tissues. Molecular oncology manifests the hallmarks of tumoral physiology with deteriorating propensity in eliminating hazardous ROS. H2O2 production was demonstrated to specifically sustain in tumors, which not only induced tumor cell apoptosis by elevated oxidation stress but also served as autochthonous H2O2 resource to trigger CPT release for chemotherapy. Excess H2O2 and released CPT could penetrate into cells efficiently, which showed synergistic cytotoxicity toward cancer cells. Systemic therapeutic trial revealed potent tumor suppression of the proposed formulation via synergistic oxidation-chemotherapy. This report represents a novel nanomedicine platform combining up-regulation of tumoral H2O2 level and self-sufficing H2O2-responsive drug release to achieve novel synergistic oxidation-chemotherapy. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Effects of macroH2A and H2A.Z on nucleosome structure and dynamics as elucidated by molecular dynamics simulations

    CERN Document Server

    Bowerman, Samuel

    2015-01-01

    Eukaryotes tune the transcriptional activity of their genome by altering the nucleosome core particle through multiple chemical processes. In particular, replacement of the canonical H2A histone with the variants macroH2A and H2A.Z has been shown to affect DNA accessibility and nucleosome stability; however, the processes by which this occurs remain poorly understood. Here, we elucidate the molecular mechanisms of these variants with an extensive molecular dynamics study of the canonical nucleosome along with three variant-containing structures: H2A.Z, macroH2A, and an H2A mutant with macroH2A-like L1 loops. Simulation results show that variant L1 loops play a pivotal role in stabilizing DNA binding to the octamer through direct interactions, core structural rearrangements, and altered allosteric networks in the nucleosome. All variants influence dynamics; however, macroH2A-like systems have the largest effect on energetics. In addition, we provide a comprehensive analysis of allosteric networks in the nucleo...

  3. Investigation into complexing in ZrO2-H2SO4-Rb2SO4(RbCl)-H2O system

    Energy Technology Data Exchange (ETDEWEB)

    Sozinova, Yu.P.; Motov, D.L.; Rys' kina, M.P.

    1986-12-01

    Solubility method is used to study zirconium and rubidium sulfate complexing: Rb4Zr4O(OH)4(SO4)7x5H2O, RbZrOH(SO4)2x1.5H2O, Rb2Zr(SO4)3x2H2O and Rb4Zr(SO4)4 in ZrO2-H2SO4-Rb2SO4(RbCl)-H2O system at 75 deg C. Introduction of RbCl instead of Rb2SO4 in the system is shown to result in change of concentration boundaries of phase existence, in a less degree - their solubility, as well as in increase of crystal size.

  4. Water Radiolysis: Influence of Oxide Surfaces on H2 Production under Ionizing Radiation

    Directory of Open Access Journals (Sweden)

    Sophie Le Caër

    2011-02-01

    Full Text Available The radiolysis of water due to ionizing radiation results in the production of electrons, H· atoms, ·OH radicals, H3O+ ions and molecules (dihydrogen H2 and hydrogen peroxide H2O2. A brief history of the development of the understanding of water radiolysis is presented, with a focus on the H2 production. This H2 production is strongly modified at oxide surfaces. Different parameters accounting for this behavior are presented.

  5. Hydrogen purification by selective methanation of CO in CO/CO2/H2

    DEFF Research Database (Denmark)

    Andersen, Anne Mette; Johannessen, Tue; Livbjerg, Hans

    : Methanation of CO and the reverse water gas shift reaction: (1) CO + 3H2 -> CH4 + H2O (2) CO2 + H2 -> CO + H2O In experiments with only CO2 and hydrogen in the feed gas there is a significant production of CO and methane. The concentration of CO in the reactor rapidly reaches a level, where it inhibits (or...

  6. Data-based adjoint and H2 optimal control of the Ginzburg-Landau equation

    Science.gov (United States)

    Banks, Michael; Bodony, Daniel

    2017-11-01

    Equation-free, reduced-order methods of control are desirable when the governing system of interest is of very high dimension or the control is to be applied to a physical experiment. Two-phase flow optimal control problems, our target application, fit these criteria. Dynamic Mode Decomposition (DMD) is a data-driven method for model reduction that can be used to resolve the dynamics of very high dimensional systems and project the dynamics onto a smaller, more manageable basis. We evaluate the effectiveness of DMD-based forward and adjoint operator estimation when applied to H2 optimal control approaches applied to the linear and nonlinear Ginzburg-Landau equation. Perspectives on applying the data-driven adjoint to two phase flow control will be given. Office of Naval Research (ONR) as part of the Multidisciplinary University Research Initiatives (MURI) Program, under Grant Number N00014-16-1-2617.

  7. Structures, physicochemical and cytoprotective properties of new oxidovanadium(IV) complexes -[VO(mIDA)(dmbipy)]·1.5H2O and [VO(IDA)(dmbipy)]·2H2O

    Science.gov (United States)

    Drzeżdżon, Joanna; Jacewicz, Dagmara; Wyrzykowski, Dariusz; Inkielewicz-Stępniak, Iwona; Sikorski, Artur; Tesmar, Aleksandra; Chmurzyński, Lech

    2017-09-01

    New oxidovanadium(IV) complexes with a modification of the ligand in the VO2+ coordination sphere were synthesized. [VO(mIDA)(dmbipy)]•1.5H2O and [VO(IDA)(dmbipy)]•2H2O were obtained as dark green crystals and grey-green powder, respectively (mIDA = N-methyliminodiacetic anion, IDA = iminodiacetic anion, dmbipy = 4,4‧-dimethoxy-2,2‧-dipyridyl). The crystal structure of [VO(mIDA)(dmbipy)]·1.5H2O has been determined by the X-ray diffraction method. The studies of structure of [VO(mIDA)(dmbipy)]•1.5H2O have shown that this compound occurs in the crystal as two rotational conformers. Furthermore, the stability constants of [VO(mIDA)(dmbipy)]•1.5H2O and [VO(IDA)(dmbipy)]•2H2O complexes in aqueous solutions were studied by using the potentiometric titration method and, consequently, determined using the Hyperquad2008 program. Moreover, the title complexes were investigated as antioxidant substances. The impact of the structure modification in the VO2+ complexes on the radical scavenging activity has been studied. The ability to scavenge the superoxide radical by two complexes - [VO(mIDA)(dmbipy)]·1.5H2O and [VO(IDA)(dmbipy)]·2H2O was studied by cyclic voltammetry (CV) and nitrobluetetrazolium (NBT) methods. The title complexes were also examined by the spectrophotometric method as scavengers of neutral organic radical - 1,1-diphenyl-2-picrylhydrazyl (DPPH•) and radical cation - 2,2'-azinobis-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS•+). Furthermore, the biological properties of two oxidovanadium(IV) complexes were investigated in relation to its cytoprotective properties by the MTT and LDH tests based on the hippocampal HT22 neuronal cell line during the oxidative damage induced by hydrogen peroxide. Finally, the results presented in this paper have shown that the both new oxidovanadium(IV) complexes with the 4,4‧-dimethoxy-2,2‧-dipyridyl ligand can be treated as the cytoprotective substances.

  8. Reassessing the variability in atmospheric H2 using the two-way nested TM5 model

    Energy Technology Data Exchange (ETDEWEB)

    Pieterse, G.; Batenburg, A.M; Roeckmann, T. [Institute for Marine and Atmospheric Research Utrecht (IMAU), Utrecht (Netherlands); Krol, M.C. [Department of Meteorology and Air Quality at Wageningen University, Wageningen (Netherlands); Brenninkmeijer, C.A.M. [Max-Planck-Institut fuer Chemie, Air Chemistry Division, Mainz (Germany); Popa, M.E.; Vermeulen, A.T. [Department of Air Quality and Climate Research at the Energy Research Centre of the Netherlands ECN, Petten (Netherlands); O' Doherty, S.; Grant, A. [School of Chemistry, University of Bristol, Bristol (United Kingdom); Steele, L.P.; Krummel, P.B.; Langenfelds, R.L. [Centre for Australian Weather and Climate Research, CSIRO Marine and Atmospheric Research, Aspendale, Victoria (Austria); Wang, H.J. [School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA (United States); Schmidt, M.; Yver, C. [Laboratoire des Sciences du Climat et de l' Environnement (LSCE), Gif-sur-Yvette (France); Jordan, A. [Max-Planck Institut fuer Biogeochemie, Jena (Germany); Engel, A. [Institut fuer Meteorologie und Geophysik, Goethe-Universitaet Frankfurt, Frankfurt (Germany); Fisher, R.E.; Lowry, D.; Nisbet, E.G. [Department of Earth Sciences, Royal Holloway, University of London, Egham (United Kingdom); Reimann, S.; Vollmer, M.K.; Steinbacher, M. [Empa, Swiss Federal Institute for Materials Science and Technology, Laboratory for Air Pollution/Environmental Technology, Duebendorf (Switzerland); Hammer, S. [Institut fuer Umweltphysik, Heidelberg Universitaet, Heidelberg (Germany); Forster, G.; Sturges, W.T. [School of Environmental Sciences, University of East Anglia, Norwich (United Kingdom)

    2013-05-16

    This work reassesses the global atmospheric budget of H2 with the TM5 model. The recent adjustment of the calibration scale for H2 translates into a change in the tropospheric burden. Furthermore, the ECMWF Reanalysis-Interim (ERA-Interim) data from the European Centre for Medium-Range Weather Forecasts (ECMWF) used in this study show slower vertical transport than the operational data used before. Consequently, more H2 is removed by deposition. The deposition parametrization is updated because significant deposition fluxes for snow, water, and vegetation surfaces were calculated in our previous study. Timescales of 1-2h are asserted for the transport of H2 through the canopies of densely vegetated regions. The global scale variability of H2 and {rho}({Delta}H2) is well represented by the updated model. H2 is slightly overestimated in the Southern Hemisphere because too little H2 is removed by dry deposition to rainforests and savannahs. The variability in H2 over Europe is further investigated using a high-resolution model subdomain. It is shown that discrepancies between the model and the observations are mainly caused by the finite model resolution. The tropospheric burden is estimated at 165{+-}8 Tg H2. The removal rates of H2 by deposition and photochemical oxidation are estimated at 53{+-}4 and 23{+-}2 Tg H2/yr, resulting in a tropospheric lifetime of 2.2{+-}0.2 year.

  9. Rapid desensitization of the histamine H2 receptor on the human monocytic cell line U937

    NARCIS (Netherlands)

    Smit, M J; Leurs, R; Shukrula, S R; Bast, A; Timmerman, H

    1994-01-01

    In the present study we have subjected the histamine H2 receptor on the monocytic cell line U937 to a thorough pharmacological characterization using a series of selective histamine H1, H2 and H3 receptor agonists and antagonists. Recent reports have demonstrated the existence of a histamine H2

  10. Overview of the Hydrogen Financial Analysis Scenario Tool (H2FAST); NREL (National Renewable Energy Laboratory)

    Energy Technology Data Exchange (ETDEWEB)

    Melaina, Marc; Bush, Brian; Penev, Michael

    2015-05-12

    This presentation provides an introduction to the Hydrogen Financial Analysis Scenario Tool (H2FAST) and includes an overview of each of the three versions of H2FAST: the Web tool, the Excel spreadsheet version, and the beta version of the H2FAST Business Case Scenario tool.

  11. Rotational quenching of H2CO by molecular hydrogen – Suggestion ...

    Indian Academy of Sciences (India)

    2016-12-05

    Dec 5, 2016 ... Abstract. Wiesenfeld and Faure investigated rotational quenching of H2CO by molecular hydrogen where they considered 40 rotational levels of o-H2CO and 41 rotational levels of p-H2CO. Data on energies of rota- tional levels of the molecule are fundamental in the investigation. We have found that the ...

  12. 20 CFR 655.1305 - Assurances and obligations of H-2A employers.

    Science.gov (United States)

    2010-04-01

    ... LABOR TEMPORARY EMPLOYMENT OF FOREIGN WORKERS IN THE UNITED STATES Labor Certification Process for Temporary Agricultural Employment in the United States (H-2A Workers) § 655.1305 Assurances and obligations of H-2A employers. An employer seeking to employ H-2A workers must attest as part of the Application...

  13. Quasi-classical trajectory study of the reaction N (4 S)+ H 2 and its ...

    Indian Academy of Sciences (India)

    To investigate the effects of reagent vibrational and rotational states on the stereodynamical properties of the N(4S) + H2(, )→NH + H reaction and its reverse reaction of H(2S) + NH(, )→N(4S) + H2, we reported a detailed quasiclassical trajectory study using the 4A" double many-body expansion potential energy ...

  14. Evaluation Of The Incidence Of Dental Caries In Patients With Down Syndrome After Their Insertion In A Preventive Program [avaliação Da Incidência De Cárie Em Pacientes Com Syndrome De Down Após Sua Inserção Em Um Programa Preventivo

    OpenAIRE

    de Castilho A.R.F.; Marta S.N.

    2010-01-01

    The objective of this work was to verify the incidence of dental caries by means of the CPO-D, CPO-S, ceo-d and ceo-s indexes in patients with Down syndrome regularly enrolled in a preventive program. Twenty four Down syndrome patients of both sexes age range of one to 48 years were examined. The prevalence (initial experimental situation) and incidence (final experimental situation) of dental caries were verified using of the initial and final CPO-D, CPO-S, ceod and ceo-s indexes of the part...

  15. Methanogenic H2 syntrophy among thermophiles: a model of metabolism, adaptation and survival in the subsurface

    Science.gov (United States)

    Topcuoglu, B. D.; Stewart, L. C.; Butterfield, D. A.; Huber, J. A.; Holden, J. F.

    2016-12-01

    Approximately 1 giga ton (Gt, 1015 g) of CH4 is formed globally per year from H2, CO2 and acetate through methanogenesis, largely by methanogens growing in syntrophic association with anaerobic microbes that hydrolyze and ferment biopolymers. However, our understanding of methanogenesis in hydrothermal regions of the subseafloor and potential syntrophic methanogenesis at thermophilic temperatures (i.e., >50°C) is nascent. In this study, the growth of natural assemblages of thermophilic methanogens from Axial Seamount was primarily limited by H2 availability. Heterotrophs supported thermophilic methanogenesis by H2 syntrophy in microcosm incubations of hydrothermal fluids at 55°C and 80°C supplemented with tryptone only. Based on 16S rRNA gene sequencing, only heterotrophic archaea that produce H2, H2-consuming methanogens, and sulfate reducing archaea were found in 80°C tryptone microcosms from Marker 113 vent. No bacteria were found. In 55°C tryptone microcosms, sequences were found from H2-producing bacteria and H2-consuming methanogens and sulfate-reducing bacteria. In order to model the impact of H2 syntrophy at hyperthemophilic temperatures, a co-culture was established consisting of the H2-producing hyperthermophilic heterotroph Thermococcus paralvinellae and a H2-consuming hyperthermophilic methanogen Methanocaldococcus bathoardescens. When grown alone in a chemostat, the growth rates and steady-state cell concentrations of T. paralvinellae decreased significantly when a high H2 (70 µM) background was present. H2 inhibition was ameliorated by the production of formate, but in silico modeling suggests less energetic yield for the cells. H2 syntrophy relieved H2 inhibition for both the heterotroph and the methanogenic partners. The results demonstrate that thermophilic H2 syntrophy can support methanogenesis within natural microbial assemblages and may be an important alternative energy source for thermophilic autotrophs in marine geothermal environments.

  16. Effects of Selenium Supplementation on Spontaneous Autoimmune Thyroiditis in NOD.H-2h4 Mice.

    Science.gov (United States)

    Wang, Weiwei; Xue, Haibo; Li, Yushu; Hou, Xin; Fan, Chenling; Wang, Hong; Zhang, Hongmei; Shan, Zhongyan; Teng, Weiping

    2015-10-01

    Recent clinical studies have demonstrated the suppressive effect of selenium (Se) treatment on serum thyroid-specific antibody titers in patients with autoimmune thyroiditis (AIT), but the mechanism underlying this process is not clear. The aim of the present study was to investigate the effects of selenium on the incidence and severity of AIT, titers of thyroid autoantibodies, and selenoprotein expression in thyroid in a spontaneous autoimmune thyroiditis (SAT) model. NOD.H-2(h4) mice at four weeks of age were randomly divided into control, iodine supplement (SAT), and selenium supplement groups (SAT+Se). Mice were given 0.005% sodium iodide water for eight weeks to induce SAT and then 0.3 mg/L sodium selenite in drinking water for 8 weeks and 16 weeks. The severity of lymphocytic infiltration in the thyroid, serum thyroglobulin antibody (TgAb) titers, serum selenium concentration, expression of glutathione peroxidase-1 (GPx1), thioredoxin reductase-1 (Txnrd1), and peroxiredoxin 5 were measured. Serum selenium concentration significantly increased after selenium supplementation. Serum TgAb levels were significantly lower in the selenium group compared with the SAT group (pselenium supplementation. The expression of GPx1 and Txnrd1 by Western blotting were found to be significantly higher in the SAT+Se group than in other groups (pselenium treatment can increase the function of antioxidation by upregulating the expression of selenoproteins in the thyroid and have an inhibitory effect on TgAb titers, which may have an impact on AIT.

  17. H2O2 levels in rainwater collected in south Florida and the Bahama Islands

    Science.gov (United States)

    Zika, R.; Saltzman, E.; Chameides, W. L.; Davis, D. D.

    1982-01-01

    Measurements of H2O2 in rainwater collected in Miami, Florida, and the Bahama Islands area indicate the presence of H2O2 concentration levels ranging from 100,000 to 700,000 M. No systematic trends in H2O2 concentration were observed during an individual storm, in marked contrast to the behavior of other anions for example, NO3(-), SO4(-2), and Cl(-). The data suggest that a substantial fraction of the H2O2 found in precipitation is generated by aqueous-phase reactions within the cloudwater rather than via rainout and washout of gaseous H2O2.

  18. Homotopy Algorithm for Fixed Order Mixed H2/H(infinity) Design

    Science.gov (United States)

    Whorton, Mark; Buschek, Harald; Calise, Anthony J.

    1996-01-01

    Recent developments in the field of robust multivariable control have merged the theories of H-infinity and H-2 control. This mixed H-2/H-infinity compensator formulation allows design for nominal performance by H-2 norm minimization while guaranteeing robust stability to unstructured uncertainties by constraining the H-infinity norm. A key difficulty associated with mixed H-2/H-infinity compensation is compensator synthesis. A homotopy algorithm is presented for synthesis of fixed order mixed H-2/H-infinity compensators. Numerical results are presented for a four disk flexible structure to evaluate the efficiency of the algorithm.

  19. One-step synthesis of fullerene hydride C(60)H2 via hydrolysis of acylated fullerenes.

    Science.gov (United States)

    Tzirakis, Manolis D; Alberti, Mariza N; Nye, Leanne C; Drewello, Thomas; Orfanopoulos, Michael

    2009-08-07

    The hitherto unexplored class of acylated fullerene compounds has been shown to be excellent C(60)H2 precursors. Upon a simple treatment with basic Al2O3, they are hydrolyzed quantitatively into C(60)H2. This key feature led to the development of a new, straightforward protocol for the selective synthesis of the simplest [60]fullerene hydride, C(60)H2. This protocol may offer an advantageous alternative to previously known methods for the synthesis of C(60)H2 allowing for a rapid access to C(60)H2 in good yield and high purity without tedious separating processes.

  20. Profiling of cytosolic and mitochondrial H2O2production using the H2O2-sensitive protein HyPer in LPS-induced microglia cells.

    Science.gov (United States)

    Park, Junghyung; Lee, Seunghoon; Lee, Hyun-Shik; Lee, Sang-Rae; Lee, Dong-Seok

    2017-07-27

    Dysregulation of the production of pro-inflammatory mediators in microglia exacerbates the pathologic process of neurodegenerative disease. ROS actively affect microglia activation by regulating transcription factors that control the expression of pro-inflammatory genes. However, accurate information regarding the function of ROS in different subcellular organelles has not yet been established. Here, we analyzed the pattern of cytosolic and mitochondrial H 2 O 2 formation in LPS-activated BV-2 microglia using the H 2 O 2- sensitive protein HyPer targeted to specific subcellular compartments. Our results show that from an early time, cytosolic H 2 O 2 started increasing constantly, whereas mitochondrial H 2 O 2 rapidly increased later. In addition, we found that MAPK affected cytosolic H 2 O 2 , but not mitochondrial H 2 O 2 . Consequently, our study provides the basic information about subcellular H 2 O 2 generation in activated microglia, and a useful tool for investigating molecular targets that can modulate neuroinflammatory responses. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Polysulfides and products of H2S/S-nitrosoglutathione in comparison to H2S, glutathione and antioxidant Trolox are potent scavengers of superoxide anion radical and produce hydroxyl radical by decomposition of H2O2.

    Science.gov (United States)

    Misak, Anton; Grman, Marian; Bacova, Zuzana; Rezuchova, Ingeborg; Hudecova, Sona; Ondriasova, Elena; Krizanova, Olga; Brezova, Vlasta; Chovanec, Miroslav; Ondrias, Karol

    2017-09-23

    Exogenous and endogenously produced sulfide derivatives, such as H 2 S/HS - /S 2- , polysulfides and products of the H 2 S/S-nitrosoglutathione interaction (S/GSNO), affect numerous biological processes in which superoxide anion (O 2 - ) and hydroxyl (OH) radicals play an important role. Their cytoprotective-antioxidant and contrasting pro-oxidant-toxic effects have been reported. Therefore, the aim of our work was to contribute to resolving this apparent inconsistency by studying sulfide derivatives/free radical interactions and their consequent biological effects compared to the antioxidants glutathione (GSH) and Trolox. Using the electron paramagnetic resonance (EPR) spin trapping technique and O 2 - , we found that a polysulfide (Na 2 S 4 ) and S/GSNO were potent scavengers of O 2 - and cPTIO radicals compared to H 2 S (Na 2 S), GSH and Trolox, and S/GSNO scavenged the DEPMPO-OH radical. As detected by the EPR spectra of DEPMPO-OH, the formation of OH in physiological solution by S/GSNO was suggested. All the studied sulfide derivatives, but not Trolox or GSH, had a bell-shaped potency to decompose H 2 O 2 and produced OH in the following order: S/GSNO > Na 2 S 4  ≥ Na 2 S > GSH = Trolox = 0, but they scavenged OH at higher concentrations. In studies of the biological consequences of these sulfide derivatives/H 2 O 2 properties, we found the following: (i) S/GSNO alone and all sulfide derivatives in the presence of H 2 O 2 cleaved plasmid DNA; (ii) S/GSNO interfered with viral replication and consequently decreased the infectivity of viruses; (iii) the sulfide derivatives induced apoptosis in A2780 cells but inhibited apoptosis induced by H 2 O 2 ; and (iv) Na 2 S 4 modulated intracellular calcium in A87MG cells, which depended on the order of Na 2 S 4 /H 2 O 2 application. We suggest that the apparent inconsistency of the cytoprotective-antioxidant and contrasting pro-oxidant-toxic biological effects of sulfide derivatives results from their time

  2. Single-Particle Laboratory Studies of Heterogeneous H2O and HCl Processing on Clean and H2SO4-Coated Aluminum Oxide Particles

    Science.gov (United States)

    Hunter, A. J.; Sonnenfroh, D. M.; Rawlins, W. T.

    2001-12-01

    Aluminum oxide particles exhausted from solid rocket motors may affect tropospheric and stratospheric radiative balance through nucleation and growth of water ice clouds, both locally in launch corridors and globally. These particles also are active toward chemisorption of HCl and dissociative chemisorption of CFCs. Plume particle surfaces are likely to contain H2SO4, possibly altering their activities toward uptake and chemical processing of HCl and HNO3. We have investigated activities of different types of aluminum oxide particles for uptake of gas-phase H2O and HCl, using a single-particle electrodynamic levitation apparatus. The particle types investigated were clean and H2SO4-treated alpha-Al2O3 and gamma-Al2O3. We also investigated metastable Al2O3 particles formed by rapid cooling from molten particles in a shock tube, analogous to particle processing in a rocket exhaust nozzle. Particles were treated with H2SO4 by vapor deposition in an oven. The kinetic measurements consisted of independent, simultaneous observations of mass uptake and particle size increase upon exposure of single levitated particles to fixed concentrations of H2O or HCl in slowly flowing gas mixtures at 1 atm. Alpha and gamma Al2O3 were essentially inert toward H2O and HCl uptake, however they readily adsorbed monolayer-equivalent levels of H2SO4 vapor. H2SO4-coated and metastable particles were active toward H2O and HCl uptake. The measured uptake efficiencies imply fast reaction rates within rocket exhaust plumes, potentially leading to CCN behavior as well as heterogeneous chlorine activation by these particles. This research was supported by the Air Force Office of Scientific Research.

  3. Invited: Tailoring Platinum Group Metals Towards Optimal Activity for Oxygen Electroreduction to H2o and H2O2: From Extended Surfaces to Nanoparticles

    DEFF Research Database (Denmark)

    Stephens, Ifan

    2014-01-01

    The slow kinetics of the 4-electron reduction of oxygen to H2O imposes a bottleneck against the widespread uptake of low temperature fuel cells in automotive vehicles. High loadings of platinum are required to drive the reaction; the limited supply of this precious metal limits the extent to which......, H2O2 is produced via the anthraquinone process, a complex, batch process, conducted in large scale facilities. The electrochemical production of H2O2 would enable on-site small scale production of hydrogen peroxide, closer to the point of consumption. The viability of the process would require...

  4. Measuring Regional and District Variations in the Incidence of Pregnancy-induced Hypertension (PIH) in Ghana : Challenges, Opportunities and Implications for Maternal and Newborn Health Policy and Programs

    NARCIS (Netherlands)

    Antwi, Edward; Klipstein-Grobusch, Kerstin; Asare, Gloria Quansah; Koram, Kwadwo A; Grobbee, Diederick; Agyepong, Irene Akua

    2016-01-01

    OBJECTIVES: The objectives were to assess the quality of health management information system (HMIS) data needed for assessment of local area variation in pregnancy induced hypertension (PIH) incidence and to describe district and regional variations in PIH incidence. METHODS: A retrospective review

  5. Differential regulation of TRPV1 channels by H2O2: implications for diabetic microvascular dysfunction

    Science.gov (United States)

    DelloStritto, Daniel J.; Connell, Patrick J.; Dick, Gregory M.; Fancher, Ibra S.; Klarich, Brittany; Fahmy, Joseph N.; Kang, Patrick T.; Chen, Yeong-Renn; Damron, Derek S.; Thodeti, Charles K.

    2016-01-01

    We demonstrated previously that TRPV1-dependent coupling of coronary blood flow (CBF) to metabolism is disrupted in diabetes. A critical amount of H2O2 contributes to CBF regulation; however, excessive H2O2 impairs responses. We sought to determine the extent to which differential regulation of TRPV1 by H2O2 modulates CBF and vascular reactivity in diabetes. We used contrast echocardiography to study TRPV1 knockout (V1KO), db/db diabetic, and wild type C57BKS/J (WT) mice. H2O2 dose-dependently increased CBF in WT mice, a response blocked by the TRPV1 antagonist SB366791. H2O2-induced vasodilation was significantly inhibited in db/db and V1KO mice. H2O2 caused robust SB366791-sensitive dilation in WT coronary microvessels; however, this response was attenuated in vessels from db/db and V1KO mice, suggesting H2O2-induced vasodilation occurs, in part, via TRPV1. Acute H2O2 exposure potentiated capsaicin-induced CBF responses and capsaicin-mediated vasodilation in WT mice, whereas prolonged luminal H2O2 exposure blunted capsaicin-induced vasodilation. Electrophysiology studies re-confirms acute H2O2 exposure activated TRPV1 in HEK293A and bovine aortic endothelial cells while establishing that H2O2 potentiate capsaicin-activated TRPV1 currents, whereas prolonged H2O2 exposure attenuated TRPV1 currents. Verification of H2O2-mediated activation of intrinsic TRPV1 specific currents were found in isolated mouse coronary endothelial cells from WT mice and decreased in endothelial cells from V1KO mice. These data suggest prolonged H2O2 exposure impairs TRPV1-dependent coronary vascular signaling. This may contribute to microvascular dysfunction and tissue perfusion deficits characteristic of diabetes. PMID:26907473

  6. Factors affecting temporal H2S emission at construction and demolition (C&D) debris landfills.

    Science.gov (United States)

    Xu, Qiyong; Townsend, Timothy

    2014-02-01

    Odor problems associated with H2S emissions often result in odor complaints from nearby residents of C&D debris landfills, especially in the early morning. As part of a field study conducted on H2S removal ability using different cover materials, daily and seasonal H2S emissions through a soil cover layer were monitored at a C&D debris landfill to investigate factors affecting H2S emissions. H2S emission rates were not a constant, but varied seasonally, with an average emission rate of 4.67×10(-6)mgm(-2)s(-1). During a the 10-month field study, as the H2S concentration increased from 140ppm to about 3500ppm underneath the cover soil in the testing cell, H2S emissions ranged from zero to a maximum emission rate of 1.24×10(-5)mgm(-2)s(-1). Continuous emission monitoring indicated that H2S emissions even changed over time throughout the day, generally increasing from morning to afternoon, and were affected by soil moisture and temperature. Laboratory experiments were also conducted to investigate the effects of H2S concentration and cover soil moisture content on H2S emissions. The results showed that increased soil moisture reduced H2S emissions by retarding H2S migration through cover soil and dissolving H2S into soil water. The field study also indicated that due to atmospheric dispersion, high H2S emissions may not cause odor problems. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. H2A/K pseudogene mutation may promote cell proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jisheng; Jing, Ruirui; Lv, Xin; Wang, Xiaoyue; Li, Junqiang; Li, Lin; Li, Cuiling; Wang, Daoguang; Bi, Baibing; Chen, Xinjun [Cancer Research Center, Shandong University School of Medicine, Jinan 250012 (China); Yang, Jing-Hua, E-mail: sdu_crc_group1@126.com [Cancer Research Center, Shandong University School of Medicine, Jinan 250012 (China); Department of Surgery, VA Boston Healthcare System, Boston University School of Medicine, Boston 510660, MA (United States)

    2016-05-15

    Highlights: • The mutant H2A/K pseudogene is active. • The mutant H2A/K pseudogene can promote cell proliferation. - Abstract: Little attention has been paid to the histone H2A/K pseudogene. Results from our laboratory showed that 7 of 10 kidney cancer patients carried a mutant H2A/K pseudogene; therefore, we were interested in determining the relationship between mutant H2A/K and cell proliferation. We used shotgun and label-free proteomics methods to study whether mutant H2A/K lncRNAs affected cell proliferation. Quantitative proteomic analysis indicated that the expression of mutant H2A/K lncRNAs resulted in the upregulation of many oncogenes, which promoted cell proliferation. Further interaction analyses revealed that a proliferating cell nuclear antigen (PCNA)-protein interaction network, with PCNA in the center, contributes to cell proliferation in cells expressing the mutant H2A/K lncRNAs. Western blotting confirmed the critical upregulation of PCNA by mutant H2A/K lncRNA expression. Finally, the promotion of cell proliferation by mutant H2A/K lncRNAs (C290T, C228A and A45G) was confirmed using cell proliferation assays. Although we did not determine the exact mechanism by which the oncogenes were upregulated by the mutant H2A/K lncRNAs, we confirmed that the mutant H2A/K lncRNAs promoted cell proliferation by upregulating PCNA and other oncogenes. The hypothesis that cell proliferation is promoted by the mutant H2A/K lncRNAs was supported by the protein expression and cell proliferation assay results. Therefore, mutant H2A/K lncRNAs may be a new factor in renal carcinogenesis.

  8. Redbourn incident

    Energy Technology Data Exchange (ETDEWEB)

    Hare, T. [Dawes Coke Ovens, Scunthorpe (United Kingdom). Corus

    2007-07-01

    On 1 February 2006 at Redbourn Stockyard, a twenty tonne forklift truck clipped a support stanchion of a vital conveyor causing the conveyor structure to collapse, bringing down essential site utilities for Dawes Lane Coke Ovens and affecting the whole of the works gas main system. The conveyor system stretches several kilometres, carrying coal to Appelby Frodingham Coke Ovens and premium coke to the blast furnaces. This report describes the incident and how Corus dealt with it to reinstate the plant in the fastest and safest time possible. The paper was presented to the Coke Oven Manufacturers Association (COMA) at Monkton Coke & Chemical Co. Ltd. on 18 May 2007. 1 fig., 6 photos.

  9. The thioredoxin and glutathione-dependent H2O2 consumption pathways in muscle mitochondria: Involvement in H2O2 metabolism and consequence to H2O2 efflux assays.

    Science.gov (United States)

    Munro, Daniel; Banh, Sheena; Sotiri, Emianka; Tamanna, Nahid; Treberg, Jason R

    2016-07-01

    The most common methods of measuring mitochondrial hydrogen peroxide production are based on the extramitochondrial oxidation of a fluorescent probe such as amplex ultra red (AUR) by horseradish peroxidase (HRP). These traditional HRP-based assays only detect H2O2 that has escaped the matrix, raising the potential for substantial underestimation of production if H2O2 is consumed by matrix antioxidant pathways. To measure this underestimation, we characterized matrix consumers of H2O2 in rat skeletal muscle mitochondria, and developed specific means to inhibit these consumers. Mitochondria removed exogenously added H2O2 (2.5µM) at rates of 4.7 and 5.0nmol min(-1) mg protein(-1) when respiring on glutamate+malate and succinate+rotenone, respectively. In the absence of respiratory substrate, or after disrupting membranes by cycles of freeze-thaw, rates of H2O2 consumption were negligible. We concluded that matrix consumers are respiration-dependent (requiring respiratory substrates), suggesting the involvement of either the thioredoxin (Trx) and/or glutathione (GSH)-dependent enzymatic pathways. The Trx-reductase inhibitor auranofin (2µM), and a pre-treatment of mitochondria with 35µM of 1-chloro-2,4-dintrobenzene (CDNB) to deplete GSH specifically compromise these two consumption pathways. These inhibition approaches presented no undesirable "off-target" effects during extensive preliminary tests. These inhibition approaches independently and additively decreased the rate of consumption of H2O2 exogenously added to the medium (2.5µM). During traditional HRP-based H2O2 efflux assays, these inhibition approaches independently and additively increased apparent efflux rates. When used in combination (double inhibition), these inhibition approaches allowed accumulation of (endogenously produced) H2O2 in the medium at a comparable rate whether it was measured with an end point assay where 2.5µM H2O2 is initially added to the medium or with traditional HRP-based efflux

  10. Tetradecacobalt(II)-containing 36-niobate [Co14(OH)16(H2O)8Nb36O106]20- and its photocatalytic H2 evolution activity.

    Science.gov (United States)

    Niu, Jingyang; Li, Fang; Zhao, Junwei; Ma, Pengtao; Zhang, Dongdi; Bassil, Bassem; Kortz, Ulrich; Wang, Jingping

    2014-08-04

    A gigantic Co14-containing 36-niobate, Na12K8[Co14(OH)16(H2O)8Nb36O106]⋅71H2O (1), has been prepared by the hydrothermal method and structurally characterized. Polyanion [Co14(OH)16(H2O)8Nb36O106](20-) (1 a) comprises a central Co7 core, surrounded by another seven isolated Co(2+) ions and six Lindqvist-type (Nb6O19) hexaniobate fragments. This is the first example of a high-nuclear cobalt-cluster-containing polyoxoniobate. The photocatalytic H2 evolution activity of Pt-loaded 1 was observed in methanol solution under irradiation using a 300 W Xe lamp. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Angular dependence of dissociative electron attachment topolyatomic molecules: application to the 2B1 metastable state of the H2Oand H2S anions

    Energy Technology Data Exchange (ETDEWEB)

    Haxton, Daniel J.; McCurdy, C. William; Rescigno, Thomas N.

    2006-01-12

    The angular dependence of dissociative electron attachment (DEA) to polyatomic targets is formulated in the local complex potential model, under the assumption that the axial recoil approximation describes the dissociation dynamics. An additional approximation, which is found to be valid in the case of H2O but not in the case of H2S, makes it possible to describe the angular dependence of DEA solely from an analysis of the fixed-nuclei entrance amplitude, without carrying out nuclear dynamics calculations. For H2S, the final-vibrational-state-specific angular dependence of DEA is obtained by incorporating the variation of the angular dependence of the entrance amplitude with nuclear geometry into the nuclear dynamics. Scattering calculations using the complex Kohn method and, for H2S, full quantum calculations of the nuclear dynamics using the Multi-Configuration Time-Dependent Hartree method, are performed.

  12. Gibbs free energy of reactions involving SiC, Si3N4, H2, and H2O as a function of temperature and pressure

    Science.gov (United States)

    Isham, M. A.

    1992-01-01

    Silicon carbide and silicon nitride are considered for application as structural materials and coating in advanced propulsion systems including nuclear thermal. Three-dimensional Gibbs free energy were constructed for reactions involving these materials in H2 and H2/H2O. Free energy plots are functions of temperature and pressure. Calculations used the definition of Gibbs free energy where the spontaneity of reactions is calculated as a function of temperature and pressure. Silicon carbide decomposes to Si and CH4 in pure H2 and forms a SiO2 scale in a wet atmosphere. Silicon nitride remains stable under all conditions. There was no apparent difference in reaction thermodynamics between ideal and Van der Waals treatment of gaseous species.

  13. Complementary version of fermion coupled coherent states method and gram-schmidt algorithm: Theory and applications for electronic states of H2 and H2.

    Science.gov (United States)

    Eidi, Mohammadreza; Vafaee, Mohsen; Rooein, Mitra

    2017-12-18

    In our previous report, we introduced a new version of Fermion coupled coherent states method (FCCS) which was especially suited for simulating the first symmetric spatial electronic state of two-electron systems. In this manuscript, we report a complementary version for FCCS method to simulate both of the first symmetric and antisymmetric spatial electronic states of two-electron systems. Moreover, the Gram-Schmidt orthogonalization process is employed to reach the excited states of the system. We apply this FCCS method and the original coupled coherent state method to simulate the energy of different electronic states of H2 and H2+, respectively. The results for the energy of computed electronic states of H2 and H2+ show a pretty good consistency with the exact values. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  14. Torsional excitation in the 2CH vibrational overtone of the C2H2-CO2 and C2H2-N2O van der Waals complexes

    Science.gov (United States)

    Lauzin, C.; Didriche, K.; Földes, T.; Herman, M.

    2011-09-01

    Infrared spectra of the weakly-bound C2H2-CO2 and C2H2-N2O complexes in the region of the 2CH acetylene overtone band (∼1.52 µm) were recorded using CW-cavity ring down spectroscopy in a continuous supersonic expansion. A new, c-type combination band is observed in each case. The rotational analysis of low J, K lines is performed and rotational constants are obtained. The band origins are 40.491(2) and 40.778(2) cm-1 higher in energy than the 2CH excitation bands for C2H2-CO2 and C2H2-N2O, respectively. The combination band is assigned in each case as involving intermolecular torsional excitation combined to 2CH. The values of the torsional vibrational frequency and of the xCH/torsion anharmonicity constant are briefly discussed.

  15. Membranes for H2 generation from nuclear powered thermochemical cycles.

    Energy Technology Data Exchange (ETDEWEB)

    Nenoff, Tina Maria; Ambrosini, Andrea; Garino, Terry J.; Gelbard, Fred; Leung, Kevin; Navrotsky, Alexandra (University of California, Davis, CA); Iyer, Ratnasabapathy G. (University of California, Davis, CA); Axness, Marlene

    2006-11-01

    In an effort to produce hydrogen without the unwanted greenhouse gas byproducts, high-temperature thermochemical cycles driven by heat from solar energy or next-generation nuclear power plants are being explored. The process being developed is the thermochemical production of Hydrogen. The Sulfur-Iodide (SI) cycle was deemed to be one of the most promising cycles to explore. The first step of the SI cycle involves the decomposition of H{sub 2}SO{sub 4} into O{sub 2}, SO{sub 2}, and H{sub 2}O at temperatures around 850 C. In-situ removal of O{sub 2} from this reaction pushes the equilibrium towards dissociation, thus increasing the overall efficiency of the decomposition reaction. A membrane is required for this oxygen separation step that is capable of withstanding the high temperatures and corrosive conditions inherent in this process. Mixed ionic-electronic perovskites and perovskite-related structures are potential materials for oxygen separation membranes owing to their robustness, ability to form dense ceramics, capacity to stabilize oxygen nonstoichiometry, and mixed ionic/electronic conductivity. Two oxide families with promising results were studied: the double-substituted perovskite A{sub x}Sr{sub 1-x}Co{sub 1-y}B{sub y}O{sub 3-{delta}} (A=La, Y; B=Cr-Ni), in particular the family La{sub x}Sr{sub 1-x}Co{sub 1-y}Mn{sub y}O{sub 3-{delta}} (LSCM), and doped La{sub 2}Ni{sub 1-x}M{sub x}O{sub 4} (M = Cu, Zn). Materials and membranes were synthesized by solid state methods and characterized by X-ray and neutron diffraction, SEM, thermal analyses, calorimetry and conductivity. Furthermore, we were able to leverage our program with a DOE/NE sponsored H{sub 2}SO{sub 4} decomposition reactor study (at Sandia), in which our membranes were tested in the actual H{sub 2}SO{sub 4} decomposition step.

  16. First results of ISO-SWS observations of Saturn : Detection of CO2, CH3C2H, C4H2 and tropospheric H2O

    NARCIS (Netherlands)

    de Graauw, Th.; Feuchtgruber, H.; Bezard, B.; Drossart, P.; Encrenaz, T.; Beintema, D. A.; Griffin, M.; Heras, A.; Kessler, M.; Leech, K.; Lellouch, E.; Morris, P.; Roelfsema, P. R.; Roos-Serote, M.; Salama, A.; Vandenbussche, B.; Valentijn, E. A.; Davis, G. R.; Naylor, D. A.

    The spectrum of Saturn has been recorded between 4.5 and 16.0 mu m with the grating mode of the Short-Wavelength Spectrometer (SWS) of ISO. The resolving power is 1500. The main results of this observation are (1) the detection of CO2 CH3C2H and C4H2 in the stratosphere and (2) the detection of H2O

  17. Continuous and jumpwise reversal magnetization in [Mn(II)(HL)(H2O)][Mn(III)(CN)6].2H2O molecular ferrimagnet

    Science.gov (United States)

    Kirman, M. V.; Vasiliev, L. A.; Morgunov, R. B.

    2017-10-01

    Magnetic jumps with the amplitudes of 0.01%-0.1% of the saturation magnetization were observed during the magnetization reversal of a [Mn(II)(HL)(H2O)][Mn(III)(CN)6].2H2O molecular ferrimagnet. Fourier transform of the time series of the magnetization jumps showed that its frequency spectrum is close to that of white noise. The distribution of the jump amplitudes versus time revealed that large jumps dominate at the onset of magnetization reversal.

  18. Nqrs Data for H4LiO5P [H2LiO4P·H2O] (Subst. No. 2280)

    Science.gov (United States)

    Chihara, H.; Nakamura, N.

    This document is part of Subvolume B 'Substances Containing C10H16 … Zn' of Volume 48 'Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III 'Condensed Matter'. It contains an extract of Section '3.2 Data tables' of the Chapter '3 Nuclear quadrupole resonance data' providing the NQRS data for H4LiO5P [H2LiO4P·H2O] (Subst. No. 2280)

  19. Influences of H2O mass fraction and chemical kinetics mechanism on the turbulent diffusion combustion of H2-O2 in supersonic flows

    Science.gov (United States)

    Huang, Wei; Wang, Zhen-guo; Li, Shi-bin; Liu, Wei-dong

    2012-07-01

    Hydrogen is one of the most promising fuels for the airbreathing hypersonic propulsion system, and it attracts an increasing attention of the researchers worldwide. In this study, a typical hydrogen-fueled supersonic combustor was investigated numerically, and the predicted results were compared with the available experimental data in the open literature. Two different chemical reaction mechanisms were employed to evaluate their effects on the combustion of H2-O2, namely the two-step and the seven-step mechanisms, and the vitiation effect was analyzed by varying the H2O mass fraction. The obtained results show that the predicted mole fraction profiles for different components show very good agreement with the available experimental data under the supersonic mixing and combustion conditions, and the chemical reaction mechanism has only a slight impact on the overall performance of the turbulent diffusion combustion. The simple mechanism of H2-O2 can be employed to evaluate the performance of the combustor in order to reduce the computational cost. The H2O flow vitiation makes a great difference to the combustion of H2-O2, and there is an optimal H2O mass fraction existing to enhance the intensity of the turbulent combustion. In the range considered in this paper, its optimal value is 0.15. The initiated location of the reaction appears far away from the bottom wall with the increase of the H2O mass fraction, and the H2O flow vitiation quickens the transition from subsonic to supersonic mode at the exit of the combustor.

  20. The interstellar chemistry of C3H and C3H2 isomers

    Science.gov (United States)

    Loison, Jean-Christophe; Agúndez, Marcelino; Wakelam, Valentine; Roueff, Evelyne; Gratier, Pierre; Marcelino, Núria; Reyes, Dianailys Nuñez; Cernicharo, José; Gerin, Maryvonne

    2017-10-01

    We report the detection of linear and cyclic isomers of C3H and C3H2 towards various starless cores and review the corresponding chemical pathways involving neutral (C3Hx with x = 1,2) and ionic (C3Hx+ with x = 1,2,3) isomers. We highlight the role of the branching ratio of electronic dissociative recombination (DR) reactions of C3H2+ and C3H3+ isomers, showing that the statistical treatment of the relaxation of C3H* and C3H2* produced in these DR reactions may explain the relative c,l-C3H and c,l-C3H2 abundances. We have also introduced in the model the third isomer of C3H2 (HCCCH). The observed cyclic-to-linear C3H2 ratio varies from 110 ± 30 for molecular clouds with a total density of about 1 × 104 molecules cm-3 to 30 ± 10 for molecular clouds with a total density of about 4 × 105 molecules cm-3, a trend well reproduced with our updated model. The higher ratio for molecular clouds with low densities is determined mainly by the importance of the H + l-C3H2 → H + c-C3H2 and H + t-C3H2 → H + c-C3H2 isomerization reactions.

  1. Hydrogen peroxide (H2O2) controls axon pathfinding during zebrafish development.

    Science.gov (United States)

    Gauron, Carole; Meda, Francesca; Dupont, Edmond; Albadri, Shahad; Quenech'Du, Nicole; Ipendey, Eliane; Volovitch, Michel; Del Bene, Filippo; Joliot, Alain; Rampon, Christine; Vriz, Sophie

    2016-06-15

    It is now becoming evident that hydrogen peroxide (H2O2), which is constantly produced by nearly all cells, contributes to bona fide physiological processes. However, little is known regarding the distribution and functions of H2O2 during embryonic development. To address this question, we used a dedicated genetic sensor and revealed a highly dynamic spatio-temporal pattern of H2O2 levels during zebrafish morphogenesis. The highest H2O2 levels are observed during somitogenesis and organogenesis, and these levels gradually decrease in the mature tissues. Biochemical and pharmacological approaches revealed that H2O2 distribution is mainly controlled by its enzymatic degradation. Here we show that H2O2 is enriched in different regions of the developing brain and demonstrate that it participates to axonal guidance. Retinal ganglion cell axonal projections are impaired upon H2O2 depletion and this defect is rescued by H2O2 or ectopic activation of the Hedgehog pathway. We further show that ex vivo, H2O2 directly modifies Hedgehog secretion. We propose that physiological levels of H2O2 regulate RGCs axonal growth through the modulation of Hedgehog pathway. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Real-time monitoring of basal H2O2 levels with peroxiredoxin-based probes.

    Science.gov (United States)

    Morgan, Bruce; Van Laer, Koen; Owusu, Theresa N E; Ezeriņa, Daria; Pastor-Flores, Daniel; Amponsah, Prince Saforo; Tursch, Anja; Dick, Tobias P

    2016-06-01

    Genetically encoded probes based on the H2O2-sensing proteins OxyR and Orp1 have greatly increased the ability to detect elevated H2O2 levels in stimulated or stressed cells. However, these proteins are not sensitive enough to monitor metabolic H2O2 baseline levels. Using yeast as a platform for probe development, we developed two peroxiredoxin-based H2O2 probes, roGFP2-Tsa2ΔCR and roGFP2-Tsa2ΔCPΔCR, that afford such sensitivity. These probes are ∼50% oxidized under 'normal' unstressed conditions and are equally responsive to increases and decreases in H2O2. Hence, they permit fully dynamic, real-time measurement of basal H2O2 levels, with subcellular resolution, in living cells. We demonstrate that expression of these probes does not alter endogenous H2O2 homeostasis. The roGFP2-Tsa2ΔCR probe revealed real-time interplay between basal H2O2 levels and partial oxygen pressure. Furthermore, it exposed asymmetry in H2O2 trafficking between the cytosol and mitochondrial matrix and a strong correlation between matrix H2O2 levels and cellular growth rate.

  3. Thermal Reactions of H2O2 on Icy Satellites and Small Bodies: Descent with Modification?

    Science.gov (United States)

    Hudson, Reggie L.; Loeffler, Mark J.

    2012-01-01

    Magnetospheric radiation drives surface and near-surface chemistry on Europa, but below a few meters Europa's chemistry is hidden from direct observation . As an example, surface radiation chemistry converts H2O and SO2 into H2O2 and (SO4)(sup 2-), respectively, and these species will be transported downward for possible thermally-driven reactions. However, while the infrared spectra and radiation chemistry of H2O2-containing ices are well documented, this molecule's thermally-induced solid-phase chemistry has seldom been studied. Here we report new results on thermal reactions in H2O + H2O2 + SO2 ices at 50 - 130 K. As an example of our results, we find that warming H2O + H2O2 + SO2 ices promotes SO2 oxidation to (SO4)(sup 2-). These results have implications for the survival of H2O2 as it descends, with modification, towards a subsurface ocean on Europa. We suspect that such redox chemistry may explain some of the observations related to the presence and distribution of H2O2 across Europa's surface as well as the lack of H2O2 on Ganymede and Callisto.

  4. Identification of small-molecule inhibitors of the ribonuclease H2 enzyme.

    Science.gov (United States)

    White, Rachel; Saxty, Barbara; Large, Jonathan; Kettleborough, Catherine A; Jackson, Andrew P

    2013-06-01

    Ribonuclease H2 (RNase H2) is a nuclease that specifically hydrolyzes RNA residues in RNA-DNA hybrids. Mutations in the RNase H2 enzyme complex have been identified in the genetic disorder Aicardi-Goutières syndrome (AGS), which has similarities to the autoimmune disease systemic lupus eryrthrematosis (SLE). The RNase H2 enzyme has also been recently implicated as a key genome surveillance enzyme. Therefore, small-molecule modulators of RNase H2 activity may have utility in therapeutics and as tools to investigate the cellular functions of RNase H2. A fluorescent quench assay, measuring cleavage of an RNA-DNA duplex substrate by recombinant RNase H2, was developed into a high-throughput format and used to screen a 48 560 compound library. A hit validation strategy was subsequently employed, leading to the identification of two novel inhibitor compounds with in vitro nanomolar range inhibition of RNase H2 activity and >100-fold selectivity compared with RNase H type 1. These compounds are the first small-molecule inhibitors of RNase H2 to be reported. They and their derivatives should provide the basis for the development of tool compounds investigating the cellular functions of the RNase H2 enzyme, and, potentially, for pharmacological manipulation of nucleic acid-mediated immune responses.

  5. Histone variant H2A.Z.2 mediates proliferation and drug sensitivity of malignant melanoma

    Science.gov (United States)

    Vardabasso, Chiara; Gaspar-Maia, Alexandre; Hasson, Dan; Pünzeler, Sebastian; Valle-Garcia, David; Straub, Tobias; Keilhauer, Eva C.; Strub, Thomas; Dong, Joanna; Panda, Taniya; Chung, Chi-Yeh; Yao, Jonathan L.; Singh, Rajendra; Segura, Miguel F.; Fontanals-Cirera, Barbara; Verma, Amit; Mann, Matthias; Hernando, Eva; Hake, Sandra B.; Bernstein, Emily

    2015-01-01

    SUMMARY Histone variants are emerging as key regulatory molecules in cancer. Here we report a novel role for the H2A.Z isoform H2A.Z.2 as a driver of malignant melanoma. H2A.Z.2 is highly expressed in metastatic melanoma, correlates with decreased patient survival, and is required for cellular proliferation. Our integrated genomic analyses reveal that H2A.Z.2 controls the transcriptional output of E2F target genes in melanoma cells. These genes are highly expressed and display a distinct signature of H2A.Z occupancy. We identify BRD2 as an H2A.Z interacting protein, whose levels are also elevated in melanoma. We further demonstrate that H2A.Z.2 regulated genes are bound by BRD2 and E2F1 in a H2A.Z.2-dependent manner. Importantly, H2A.Z.2 deficiency sensitizes melanoma cells to chemotherapy and targeted therapies. Collectively, our findings implicate H2A.Z.2 as a mediator of cell proliferation and drug sensitivity in malignant melanoma, holding translational potential for novel therapeutic strategies. PMID:26051178

  6. H2S: a "double face" molecule in health and disease.

    Science.gov (United States)

    di Masi, Alessandra; Ascenzi, Paolo

    2013-01-01

    H2S is a colorless, poisonous, and flammable gas with the characteristic foul odor of rotten eggs. H2S is present in effluent from hydrothermal vents and sulfur springs, which have been proposed to act as "pores" in the Earth surface, providing a source of energy in the form of reducing equivalents and of iron-sulfur centers. Remarkably, H2S-producing machineries or H2S-utilization capacity remain within a great diversity of microorganisms. In particular, two classes of bacteria have been identified, that is, sulfate- and sulfur-reducing and sulfur-oxidizing bacteria, both contributing to the balance of the H2S level. The human body produces H2S and uses it as a signaling molecule in several physiological processes. However, many diseases, including neurological diseases, cardiovascular diseases, inflammation, and metabolic disorders, have been linked to abnormal endogenous H2S functions and metabolism. Remarkably, in recent years, the therapeutic administration of H2S(-donors) appears relevant in the treatment of some diseases. Here, H2S metabolism, as well as its physiological and pathological roles in humans is reviewed. Furthermore, the therapeutic use of H2S is discussed. Copyright © 2012 International Union of Biochemistry and Molecular Biology, Inc.

  7. A year of H2 measurements at Weybourne Atmospheric Observatory, UK

    Directory of Open Access Journals (Sweden)

    Grant L. Forster

    2012-07-01

    Full Text Available We present a year-long high precision time series of atmospheric molecular hydrogen (H2 measured at the UK North Sea coast from March 2008 to February 2009. We observed a pronounced seasonal cycle in H2 with mean values in late winter/early spring ~40 ppb higher than those in late summer/early autumn. Background-subtracted molar H2/CO ratios (ΔH2/ΔCO averaged 0.35±0.002 for all data combined and 0.25±0.002 when ΔH2 was above 10 ppb. The ΔH2/ΔCO ratio was highest in summer, possibly as a result of larger photochemical production. Using simultaneous measurements of ozone, we estimated the deposition velocity of H2 during nocturnal inversion events to average 3.5±0.7×10−4 m s−1 for June 2008 and 1.9±1×10−4 m s−1 for July 2008, in good agreement with other reported estimates. In May 2008, we observed an episode of exceptionally clean air being transported from the tropics but arriving from the north, in which H2 was slightly elevated indicating minimal surface loss. On another occasion with south-easterly winds, we believe we detected emissions from H2 production facilities in the near-continent characterised by H2 mixing ratios reaching 1450 ppb.

  8. Histone H2AX phosphorylation is associated with most meiotic events in grasshopper.

    Science.gov (United States)

    Cabrero, J; Teruel, M; Carmona, F D; Camacho, J P M

    2007-01-01

    It is widely accepted that the H2AX histone in its phosphorylated form (gamma-H2AX) is related to the repair of DNA double-strand breaks (DSBs). In several organisms, gamma-H2AX presence has been demonstrated in meiotic processes such as recombination and sex chromosome inactivation during prophase I (from leptotene to pachytene). To test whether gamma-H2AX is present beyond pachytene, we have analysed the complete sequence of changes in H2AX phosphorylation during meiosis in grasshopper, a model organism for meiotic studies at the cytological level. We show the presence of phosphorylated H2AX during most of meiosis, with the exception only of diplotene and the end of each meiotic division. During the first meiotic division, gamma-H2AX is associated with i) recombination, as deduced from its presence in leptotene-zygotene over all chromosome length, ii) X chromosome inactivation, since at pachytene gamma-H2AX is present in the X chromosome only, and iii) chromosome segregation, as deduced from gamma-H2AX presence in centromere regions at first metaphase-anaphase. During second meiotic division, gamma-H2AX was very abundant at most chromosome lengths from metaphase to telophase, suggesting its possible association with the maintenance of chromosome condensation and segregation. Copyright 2007 S. Karger AG, Basel.

  9. Histone H2B mono-ubiquitylation maintains genomic integrity at stalled replication forks

    Science.gov (United States)

    Northam, Matthew R.; Trujillo, Kelly M.

    2016-01-01

    Histone modifications play an important role in regulating access to DNA for transcription, DNA repair and DNA replication. A central player in these events is the mono-ubiquitylation of histone H2B (H2Bub1), which has been shown to regulate nucleosome dynamics. Previously, it was shown that H2Bub1 was important for nucleosome assembly onto nascent DNA at active replication forks. In the absence of H2Bub1, incomplete chromatin structures resulted in several replication defects. Here, we report new evidence, which shows that loss of H2Bub1 contributes to genomic instability in yeast. Specifically, we demonstrate that H2Bub1-deficient yeast accumulate mutations at a high frequency under conditions of replicative stress. This phenotype is due to an aberrant DNA Damage Tolerance (DDT) response upon fork stalling. We show that H2Bub1 normally functions to promote error-free translesion synthesis (TLS) mediated by DNA polymerase eta (Polη). Without H2Bub1, DNA polymerase zeta (Polζ) is responsible for a highly mutagenic alternative mechanism. While H2Bub1 does not appear to regulate other DDT pathways, error-free DDT mechanisms are employed by H2Bub1-deficient cells as another means for survival. However, in these instances, the anti-recombinase, Srs2, is essential to prevent the accumulation of toxic HR intermediates that arise in an unconstrained chromatin environment. PMID:27458205

  10. The Role of Peroxiredoxins in the Transduction of H2O2 Signals.

    Science.gov (United States)

    Rhee, Sue Goo; Woo, Hyun Ae; Kang, Dongmin

    2017-07-10

    Hydrogen peroxide (H2O2) is produced on stimulation of many cell surface receptors and serves as an intracellular messenger in the regulation of diverse physiological events, mostly by oxidizing cysteine residues of effector proteins. Mammalian cells express multiple H2O2-eliminating enzymes, including catalase, glutathione peroxidase (GPx), and peroxiredoxin (Prx). A conserved cysteine in Prx family members is the site of oxidation by H2O2. Peroxiredoxins possess a high-affinity binding site for H2O2 that is lacking in catalase and GPx and which renders the catalytic cysteine highly susceptible to oxidation, with a rate constant several orders of magnitude greater than that for oxidation of cysteine in most H2O2 effector proteins. Moreover, Prxs are abundant and present in all subcellular compartments. The cysteines of most H2O2 effectors are therefore at a competitive disadvantage for reaction with H2O2. Recent Advances: Here we review intracellular sources of H2O2 as well as H2O2 target proteins classified according to biochemical and cellular function. We then highlight two strategies implemented by cells to overcome the kinetic disadvantage of most target proteins with regard to H2O2-mediated oxidation: transient inactivation of local Prx molecules via phosphorylation, and indirect oxidation of target cysteines via oxidized Prx. Critical Issues and Future Directions: Recent studies suggest that only a small fraction of the total pools of Prxs and H2O2 effector proteins localized in specific subcellular compartments participates in H2O2 signaling. Development of sensitive tools to selectively detect phosphorylated Prxs and oxidized effector proteins is needed to provide further insight into H2O2 signaling. Antioxid. Redox Signal. 00, 000-000.

  11. A novel source of atmospheric H2: abiotic degradation of organic material

    Directory of Open Access Journals (Sweden)

    H. L. Throop

    2012-11-01

    Full Text Available Molecular hydrogen (H2 plays an important role in atmospheric chemistry by competing for reactions with the hydroxyl radical (OH· and contributing to the production of H2O in the stratosphere, indirectly influencing stratospheric ozone concentrations. The dominant pathway for loss of H2 from the atmosphere is via microbially-mediated soil uptake, although the magnitude of this loss is still regarded as highly uncertain. Recent studies have shown that abiotic processes such as photochemically mediated degradation (photodegradation of organic material result in direct emissions of carbon (C and nitrogen (N-based trace gases as well as H2. This H2 production has important implications on source-sink dynamics of H2 at the soil-atmosphere interface and thus it is important to quantify its variability over a range of plant types and materials. Here, we show laboratory observations of H2 production and its temperature dependence during abiotic degradation of four plant litter types as well as pure cellulose and high lignin content woody material. A greater amount of H2 was produced in the absence of solar radiation than from photodegradation alone, verifying that low temperature thermal degradation of plant litter is a source of H2. In addition, we measured a significant release of H2 both in the presence and absence of O2. Our results suggest that abiotic release of H2 during organic matter degradation is ubiquitous in arid ecosystems and may also occur in other terrestrial ecosystems. We propose that because these processes occur at the soil-atmosphere interface, they provide a previously unrecognized proximal source of H2 for microbial uptake and confound interpretation of direct measurements of atmospheric uptake that are important for constraining the global H2 budget.

  12. Rate constant for the H˙ + H2O → ˙OH + H2reaction at elevated temperatures measured by pulse radiolysis.

    Science.gov (United States)

    Muroya, Y; Yamashita, S; Lertnaisat, P; Sanguanmith, S; Meesungnoen, J; Jay-Gerin, J-P; Katsumura, Y

    2017-11-22

    Maintaining the structural integrity of materials in nuclear power plants is an essential issue associated with safe operation. Hydrogen (H 2 ) addition or injection to coolants is a powerful technique that has been widely applied such that the reducing conditions in the coolant water avoid corrosion and stress corrosion cracking (SCC). Because the radiation-induced reaction of ˙OH + H 2 → H˙ + H 2 O plays a crucial role in these systems, the rate constant has been measured at operation temperatures of the reactors (285-300 °C) by pulse radiolysis, generating sufficient data for analysis. The reverse reaction H˙ + H 2 O → ˙OH + H 2 is negligibly slow at ambient temperature; however, it accelerates considerably quickly at elevated temperatures. Although the reverse reaction reduces the effectiveness of H 2 addition, reliable rate constants have not yet been measured. In this study, the rate constants have been determined in a temperature range of 250-350 °C by pulse radiolysis in an aqueous I - solution.

  13. Time-multiplexed open-path TDLAS spectrometer for dynamic, sampling-free, interstitial H2 18O and H2 16O vapor detection in ice clouds

    Science.gov (United States)

    Kühnreich, B.; Wagner, S.; Habig, J. C.; Möhler, O.; Saathoff, H.; Ebert, V.

    2015-04-01

    An advanced in situ diode laser hygrometer for simultaneous, sampling-free detection of interstitial H2 16O and H2 18O vapor was developed and tested in the aerosol interaction and dynamics in atmosphere (AIDA) cloud chamber during dynamic cloud formation processes. The spectrometer to measure isotope-resolved water vapor concentrations comprises two rapidly time-multiplexed DFB lasers near 1.4 and 2.7 µm and an open-path White cell with 227-m absorption path length and 4-m mirror separation. A dynamic water concentration range from 2.6 ppb to 87 ppm for H2 16O and 87 ppt to 3.6 ppm for H2 18O could be achieved and was used to enable a fast and direct detection of dynamic isotope ratio changes during ice cloud formation in the AIDA chamber at temperatures between 190 and 230 K. Relative changes in the H2 18O/H2 16O isotope ratio of 1 % could be detected and resolved with a signal-to-noise ratio of 7. This converts to an isotope ratio resolution limit of 0.15 % at 1-s time resolution.

  14. High resolution pore water delta2H and delta18O measurements by H2O(liquid)-H2O(vapor) equilibration laser spectroscopy.

    Science.gov (United States)

    Wassenaar, L I; Hendry, M J; Chostner, V L; Lis, G P

    2008-12-15

    A new H2O(liquid)-H2O(vapor) pore water equilibration and laser spectroscopy method provides a fast way to obtain accurate high resolution deltaD and delta18O profiles from single core samples from saturated and unsaturated geologic media. The precision and accuracy of the H2O(liquid)-H2O(vapor) equilibration method was comparable to or better than conventional IRMS-based methods, and it can be conducted on geologic cores that contain volumetric water contents as low as 5%. Significant advantages of the H2O(liquid)-H2O(vapor) pore water equilibration method and laser isotopic analysis method include dual hydrogen- and oxygen-isotope assays on single small core samples, low consumable and instrumentation costs, and the potential for field-based hydrogeologic profiling. A single core is sufficient to obtain detailed vertical isotopic depth profiles in geologic, soil, and lacustrine pore water, dramatically reducing the cost of obtaining pore water by conventional wells or physical water extraction methods. In addition, other inherent problems like contamination of wells by leakage and drilling fluids can be eliminated.

  15. Ascending the nucleosome face: recognition and function of structured domains in the histone H2A-H2B dimer.

    Science.gov (United States)

    Wyrick, John J; Kyriss, McKenna N M; Davis, William B

    2012-08-01

    Research over the past decade has greatly expanded our understanding of the nucleosome's role as a dynamic hub that is specifically recognized by many regulatory proteins involved in transcription, silencing, replication, repair, and chromosome segregation. While many of these nucleosome interactions are mediated by post-translational modifications in the disordered histone tails, it is becoming increasingly apparent that structured regions of the nucleosome, including the histone fold domains, are also recognized by numerous regulatory proteins. This review will focus on the recognition of structured domains in the histone H2A-H2B dimer, including the acidic patch, the H2A docking domain, the H2B α3-αC helices, and the HAR/HBR domains, and will survey the known biological functions of histone residues within these domains. Novel post-translational modifications and trans-histone regulatory pathways involving structured regions of the H2A-H2B dimer will be highlighted, along with the role of intrinsic disorder in the recognition of structured nucleosome regions. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Terahertz Spectroscopy of the Bending Vibrations of Acetylene 12C2H2 and 12C2D2

    Science.gov (United States)

    Yu, Shanshan; Drouin, B.; Pearson, J.

    2009-12-01

    Several fundamental interstellar molecules, e.g., C2H2, CH4 and C3, are completely symmetric molecules and feature no permanent dipole moment and no pure rotation spectrum. As a result they have only previously been observed in the infrared. However, directly observing them with the rest of the molecular column especially when the source is spatially resolved would be very valuable in understanding chemical evolution. Vibrational difference bands provide a means to detect symmetric molecules with microwave precision using terahertz techniques. Herschel, SOFIA and ALMA have the potential to identify a number of vibrational difference bands of light symmetric species. This paper reports laboratory results on 12C2H2 and 12C2D2. Symmetric acetylene isotopologues have two bending modes, the trans bending and the cis bending. Their difference bands are allowed and occur in the microwave, terahertz, and far-infrared wavelengths, with band origins at 3500 GHz for 12C2H2 and 900 GHz for 12C2D2. Twenty 12C2H2 P branch high-J transitions and two hundred and fifty-one 12C2D2 P Q and R branch transitions have been measured in the 0.2 - 1.6 THz region with precision of 50 to 100 kHz. These lines were modeled together with prior data on the pure bending levels. Significantly improved molecular parameters were obtained for 12C2H2 and 12C2D2 with the combined data set, and new frequency and intensity predictions were made to support astrophysics applications. The research was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. S. Y. was supported by an appointment to the NASA Postdoctoral Program, administrated by Oak Ridge Associated Universities through a contract with NASA.

  17. Crystal structures of hydrates of simple inorganic salts. III. Water-rich aluminium halide hydrates: AlCl3 · 15H2O, AlBr3 · 15H2O, AlI3 · 15H2O, AlI3 · 17H2O and AlBr3 · 9H2O.

    Science.gov (United States)

    Schmidt, Horst; Hennings, Erik; Voigt, Wolfgang

    2014-09-01

    Water-rich aluminium halide hydrate structures are not known in the literature. The highest known water content per Al atom is nine for the perchlorate and fluoride. The nonahydrate of aluminium bromide, stable pentadecahydrates of aluminium chloride, bromide and iodide, and a metastable heptadecahydrate of the iodide have now been crystallized from low-temperature solutions. The structures of these hydrates were determined and are discussed in terms of the development of cation hydration spheres. The pentadecahydrate of the chloride and bromide are isostructural. In AlI(3) · 15H2O, half of the Al(3+) cations are surrounded by two complete hydration spheres, with six H2O in the primary and 12 in the secondary. For the heptadecahydrate of aluminium iodide, this hydration was found for every Al(3+).

  18. Gaining Insights on the H2–Sorbent Interactions: Robust soc-MOF Platform as a Case Study

    KAUST Repository

    Cairns, Amy

    2016-09-18

    We report on the synthesis and gas adsorption properties (i.e., Ar and H2) of four robust 3-periodic metal–organic frameworks (MOFs) having the targeted soc topology. These cationic MOFs are isostructural to the parent indium-based MOF, In-soc-MOF-1a (for NO3–), previously reported by us, and likewise are constructed from the assembly of rigid μ3-oxygen-centered trinuclear metal carboxylate clusters, [M3O(O2C−)6], where M = In3+ or Fe3+. Each inorganic trinuclear molecular building block (MBB), generated in situ, is bridged by six 3,3′,5,5′-azobenzenetetracarboxylate (ABTC4–) ligands to give the extended (4,6)-connected MOF, soc-MOF. In our previous work, we confirmed that the parent soc-MOF, i.e., In-soc-MOF-1a, possesses unique structural characteristics (e.g., vacant In binding sites and narrow pores with higher localized charge density), which led to exceptional hydrogen (H2) storage capabilities. Therefore, charged MOFs with soc topology can be viewed collectively as an ideal prototypical platform to examine the impact of specific structural parameters on H2–MOF interactions via systematic gas adsorption studies. We infer that enhanced binding of molecular H2 is primarily governed by the presence and type of vacant metal centers (i.e., Fe was shown to exhibit stronger H2–MOF interactions at low H2 loading compared to the In analogues). These findings are evident from the associated isosteric heat of adsorption (Qst) at low loadings and inelastic neutron scattering (INS) experiments of the rotational transitions of sorbed H2, as well as, temperature-programmed desorption (TPD) studies (for a select compound). The importance of localized charge density is also highlighted, where the extra-framework nitrate anions in the Fe-soc-MOF-1a (for NO3–) facilitate enhanced binding affinities as compared to the chloride analogue.

  19. 75 FR 61577 - Wage Methodology for the Temporary Non-Agricultural Employment H-2B Program

    Science.gov (United States)

    2010-10-05

    ... Process for Temporary Employment in Occupations other than Agriculture or Registered Nursing in the United... models of labor supply and demand, an increase in the wage rate represents an increased production cost to employers leading to a reduction in the demand for labor. Because production costs increase with...

  20. 76 FR 21036 - Application of the Prevailing Wage Methodology in the H-2B Program

    Science.gov (United States)

    2011-04-14

    .... Carlson, PhD, Administrator, Office of Foreign Labor Certification, U.S. Department of Labor, 200... Foreign Labor Certification, U.S. Department of Labor, ] Room C4312, 200 Constitution Avenue, NW... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF LABOR...

  1. Phosphorylation of BK channels modulates the sensitivity to hydrogen sulfide (H2S

    Directory of Open Access Journals (Sweden)

    Guzel F. Sitdikova

    2014-11-01

    Full Text Available Introduction: Gases, such as nitric oxide (NO, carbon monoxide (CO or hydrogen sulfide (H2S, termed gasotransmitters, play an increasingly important role in understanding of how electrical signaling of cells is modulated. H2S is well known to act on various ion channels and receptors. In a previous study we reported that H2S increased calcium-activated potassium (BK channel activity. Aims: The goal of the present study is to investigate the modulatory effect of BK channel phosphorylation on the action of H2S on the channel as well as to recalculate and determine the H2S concentrations in aqueous sodium hydrogen sulfide (NaHS solutions.Methods: Single channel recordings of GH3, GH4 and GH4 STREX cells were used to analyze channel open probability, amplitude and open dwell times. H2S was measured with ananion selective electrode. Results: The concentration of H2S produced from NaHS was recalculated taking pH, temperature salinity of the perfusate and evaporation of H2S into account. The results indicate that from a concentration of 300 µM NaHS, only11-13%, i.e. 34-41 µM is effective as H2S in solution. GH3, GH4 and GH4 STREX cells respond differently to phosphorylation. BK channel open probability (Po of all cells lines used was increased by H2S in ATP containing solutions. PKA prevented the action of H2S on channel Po in GH4 and GH4 STREX, but not in GH3 cells. H2S, high significantly increased Po of all PKG pretreated cells. In the presence of PKC, which lowers channel activity, H2S increased channel Po of GH4 and GH4 STREX, but not those of GH3 cells. H2S increased open dwell times of GH3 cells in the absence of ATP significantly. A significant increase of dwell times with H2S was also observed in the presence of okadaic acid.Conclusions: Our results suggest that phosphorylation by PKG primes the channels for H2S activation and indicate that channel phosphorylation plays an important role in the response to H2S.

  2. High resolution spectroscopy of the Martian atmosphere - Study of seasonal variations of CO, O3, H2O, and T on the north polar cap and a search for SO2, H2O2, and H2CO

    Science.gov (United States)

    Krasnopolsky, V. A.; Chakrabarti, S.; Larson, H.; Sandel, B. R.

    1992-01-01

    An overview is presented of an observational campaign which will measure (1) the seasonal variations of the CO mixing ratio on the Martian polar cap due to accumulation and depletion of CO during the condensation and evaporation of CO2, as well as (2) the early spring ozone and water vapor of the Martian north polar cap, and (3) the presence of H2CO, H2O2, and SO2. The lines of these compounds will be measured by a combined 4-m telescope and Fourier-transform spectrometer 27097.

  3. Transcriptome analysis of H2O2-treated wheat seedlings reveals a H2O2-responsive fatty acid desaturase gene participating in powdery mildew resistance.

    Directory of Open Access Journals (Sweden)

    Aili Li

    Full Text Available Hydrogen peroxide (H(2O(2 plays important roles in plant biotic and abiotic stress responses. However, the effect of H(2O(2 stress on the bread wheat transcriptome is still lacking. To investigate the cellular and metabolic responses triggered by H(2O(2, we performed an mRNA tag analysis of wheat seedlings under 10 mM H(2O(2 treatment for 6 hour in one powdery mildew (PM resistant (PmA and two susceptible (Cha and Han lines. In total, 6,156, 6,875 and 3,276 transcripts were found to be differentially expressed in PmA, Han and Cha respectively. Among them, 260 genes exhibited consistent expression patterns in all three wheat lines and may represent a subset of basal H(2O(2 responsive genes that were associated with cell defense, signal transduction, photosynthesis, carbohydrate metabolism, lipid metabolism, redox homeostasis, and transport. Among genes specific to PmA, 'transport' activity was significantly enriched in Gene Ontology analysis. MapMan classification showed that, while both up- and down- regulations were observed for auxin, abscisic acid, and brassinolides signaling genes, the jasmonic acid and ethylene signaling pathway genes were all up-regulated, suggesting H(2O(2-enhanced JA/Et functions in PmA. To further study whether any of these genes were involved in wheat PM response, 19 H(2O(2-responsive putative defense related genes were assayed in wheat seedlings infected with Blumeria graminis f. sp. tritici (Bgt. Eight of these genes were found to be co-regulated by H(2O(2 and Bgt, among which a fatty acid desaturase gene TaFAD was then confirmed by virus induced gene silencing (VIGS to be required for the PM resistance. Together, our data presents the first global picture of the wheat transcriptome under H(2O(2 stress and uncovers potential links between H(2O(2 and Bgt responses, hence providing important candidate genes for the PM resistance in wheat.

  4. Exposure of insect cells to ionising radiation in vivo induces persistent phosphorylation of a H2AX homologue (H2AvB).

    Science.gov (United States)

    Siddiqui, Mohammad S; Filomeni, Erika; François, Maxime; Collins, Samuel R; Cooper, Tamara; Glatz, Richard V; Taylor, Phillip W; Fenech, Michael; Leifert, Wayne R

    2013-09-01

    The response of eukaryotic cells to ionising radiation (IR)-induced double-strand DNA breaks is highly conserved and involves a DNA repair mechanism characterised by the early phosphorylation of histone protein H2AX (producing the active form γH2AX). Although the expression of an induced γH2AX variant has been detected in Drosophila melanogaster, the expression and radiation response of a γH2AX homologue has not been reported in economically important fruit flies. We use Bactrocera tryoni (Diptera: Tephritidae, Queensland fruit fly or 'Q-fly') to investigate this response with a view to developing molecular assays to detect/quantify exposure of fruit flies to IR and consequent DNA damage. Deep sequencing confirmed the presence of a H2AX homologue that we have termed H2AvB (i.e. variant Bactrocera) and has an identical sequence to a histone reported from the human disease vector Glossina morsitans. A linear dose-response of γH2AvB (0-400 Gy IR) was observed in whole Q-fly pupal lysates 24h post-IR and was detected at doses as low as 20 Gy. γH2AvB signal peaked at ~20min after IR exposure and at 24h post-IR the signal remained elevated but declined significantly by 5 days. Persistent and dose-dependent γH2AvB signal could be detected and quantified either by western blot or by laser scanning cytometry up to 17 days post-IR exposure in histone extracts or isolated nuclei from adult Q-flies (irradiated as pupae). We conclude that IR exposure in Q-fly leads to persistent γH2AvB signals (over a period of days) that can easily be detected by western blot or quantitative immunofluorescence techniques. These approaches have potential as the basis for assays for detection and quantification of prior IR exposure in pest fruit flies.

  5. Reorganization of Damaged Chromatin by the Exchange of Histone Variant H2A.Z-2

    Energy Technology Data Exchange (ETDEWEB)

    Nishibuchi, Ikuno [Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima (Japan); Department of Radiation Oncology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima (Japan); Department of Radiation Oncology, Hiroshima Prefectural Hospital, Hiroshima (Japan); Suzuki, Hidekazu; Kinomura, Aiko; Sun, Jiying; Liu, Ning-Ang [Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima (Japan); Horikoshi, Yasunori [Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima (Japan); Research Center for Mathematics of Chromatin Live Dynamics, Hiroshima University, Hiroshima (Japan); Shima, Hiroki [Department of Biochemistry, Graduate School of Medical Sciences, Tohoku University, Sendai (Japan); Kusakabe, Masayuki; Harata, Masahiko [Laboratory of Molecular Biology, Graduate School of Agricultural Science, Tohoku University, Sendai (Japan); Fukagawa, Tatsuo [Department of Molecular Genetics, National Institute of Genetics and The Graduate University for Advanced Studies, Mishima (Japan); Ikura, Tsuyoshi [Laboratory of Chromatin Regulatory Network, Department of Mutagenesis, Radiation Biology Center, Kyoto University, Kyoto (Japan); Ishida, Takafumi [Department of Cardiovascular Medicine, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima (Japan); Nagata, Yasushi [Department of Radiation Oncology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima (Japan); Tashiro, Satoshi, E-mail: ktashiro@hiroshima-u.ac.jp [Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima (Japan); Research Center for Mathematics of Chromatin Live Dynamics, Hiroshima University, Hiroshima (Japan)

    2014-07-15

    Purpose: The reorganization of damaged chromatin plays an important role in the regulation of the DNA damage response. A recent study revealed the presence of 2 vertebrate H2A.Z isoforms, H2A.Z-1 and H2A.Z-2. However, the roles of the vertebrate H2A.Z isoforms are still unclear. Thus, in this study we examined the roles of the vertebrate H2A.Z isoforms in chromatin reorganization after the induction of DNA double-strand breaks (DSBs). Methods and Materials: To examine the dynamics of H2A.Z isoforms at damaged sites, we constructed GM0637 cells stably expressing each of the green fluorescent protein (GFP)-labeled H2A.Z isoforms, and performed fluorescence recovery after photobleaching (FRAP) analysis and inverted FRAP analysis in combination with microirradiation. Immunofluorescence staining using an anti-RAD51 antibody was performed to study the kinetics of RAD51 foci formation after 2-Gy irradiation of wild-type (WT), H2A.Z-1- and H2A.Z-2-deficient DT40 cells. Colony-forming assays were also performed to compare the survival rates of WT, H2A.Z-1-, and H2A.Z-2-deficient DT40 cells with control, and H2A.Z-1- and H2A.Z-2-depleted U2OS cells after irradiation. Results: FRAP analysis revealed that H2A.Z-2 was incorporated into damaged chromatin just after the induction of DSBs, whereas H2A.Z-1 remained essentially unchanged. Inverted FRAP analysis showed that H2A.Z-2 was released from damaged chromatin. These findings indicated that H2A.Z-2 was exchanged at DSB sites immediately after the induction of DSBs. RAD51 focus formation after ionizing irradiation was disturbed in H2A.Z-2-deficient DT40 cells but not in H2A.Z-1-deficient cells. The survival rate of H2A.Z-2-deficient cells after irradiation was lower than those of WT and H2A.Z-1- DT40 cells. Similar to DT40 cells, H2A.Z-2-depleted U2OS cells were also radiation-sensitive compared to control and H2A.Z-1-depleted cells. Conclusions: We found that vertebrate H2A.Z-2 is involved in the regulation of the DNA

  6. Silicon photonic dual-gas sensor for H2 and CO2 detection.

    Science.gov (United States)

    Mi, Guangcan; Horvath, Cameron; Van, Vien

    2017-07-10

    We report a silicon photonic dual-gas sensor based on a wavelength-multiplexed microring resonator array for simultaneous detection of H2 and CO2 gases. The sensor uses Pd as the sensing layer for H2 gas and a novel functional material based on the Polyhexamethylene Biguanide (PHMB) polymer for CO2 gas sensing. Gas sensing experiments showed that the PHMB-functionalized microring exhibited high sensitivity to CO2 gas and excellent selectivity against H2. However, the Pd-functionalized microring was found to exhibit sensitivity to both H2 and CO2 gases, rendering it ineffective for detecting H2 in a gas mixture containing CO2. We show that the dual-gas sensing scheme can allow for accurate measurement of H2 concentration in the presence of CO2 by accounting for the cross-sensitivity of Pd to the latter.

  7. Search Directions for Direct H2O2 Synthesis Catalysts Starting from Au-12 Nanoclusters

    DEFF Research Database (Denmark)

    Grabow, Lars; Larsen, Britt Hvolbæk; Falsig, Hanne

    2012-01-01

    We present density functional theory calculations on the direct synthesis of H2O2 from H-2 and O-2 over an Au-12 corner model of a gold nanoparticle. We first show a simple route for the direct formation of H2O2 over a gold nanocatalyst, by studying the energetics of 20 possible elementary...... that the rate of H2O2 and H2O formation can be determined from a single descriptor, namely, the binding energy of oxygen (E-O). Our model predicts the search direction starting from an Au-12 nanocluster for an optimal catalyst in terms of activity and selectivity for direct H2O2 synthesis. Taking also stability...

  8. Comparison of different methods for localizing antigenic regions in histone H2A.

    Science.gov (United States)

    Muller, S; Plaue, S; Couppez, M; Van Regenmortel, M H

    1986-06-01

    Four different variations of enzyme-linked immunosorbent assays (ELISA) were used to analyze the antigenic structure of histone H2A. Eleven natural and 10 synthetic peptides of H2A were tested for their capacity to bind antibodies raised against the complete molecule in a direct binding assay. Results were compared to those obtained in a direct test using several peptide-BSA conjugates. The capacity of peptides to inhibit the reaction between H2A antibodies and the complete H2A molecule or large fragments of it was also measured. Inhibition assays detected antigenic activity in a large number of peptides than did direct binding assays. Antisera raised against eight synthetic, unconjugated peptides all reacted with histone H2A in ELISA. Using as probes peptides of 14-21 residues, at least 11 antigenic regions could be recognized, indicating that virtually the entire H2A polypeptide chain possessed antigenic activity.

  9. Inhibition of Gastric Acid Secretion by H2 Receptor Antagonists Associates a Definite Risk of Enteric Peritonitis and Infectious Mortality in Patients Treated with Peritoneal Dialysis.

    Science.gov (United States)

    Pérez-Fontan, Miguel; Machado Lopes, Daniela; García Enríquez, Alba; López-Calviño, Beatriz; López-Muñiz, Andrés; García Falcón, Teresa; Rodríguez-Carmona, Ana

    2016-01-01

    Evidences linking treatment with inhibitors of gastric acid secretion (IGAS) and an increased risk of serious infections are inconclusive, both in the population at large and in the particular case of patients with chronic kidney disease. We have undertaken an investigation to disclose associations between treatment with IGAS and infectious outcomes, in patients undergoing chronic Peritoneal Dialysis (PD). Observational, historic cohort, single center design. Six hundred and ninety-one patients incident on PD were scrutinized for an association among treatment with IGAS (H2 antagonists H2A or proton pump inhibitors PPI) (main study variable), on one side, and the risks of enteric peritoneal infection (main outcome), overall peritoneal infection, and general and infectious mortality (secondary outcomes). We applied a three-step multivariate approach, based on classic Cox models (baseline variables), time-dependent analyses and, when appropriate, competing risk analyses. The clinical characteristics of patients treated with H2A, PPI or none of these were significantly different. Multivariate analyses disclosed a consistently increased risk of enteric peritonitis in patients treated with IGAS (RR 1.65, 95% CI 1.08-2.55, p = 0.018, Cox). Stratified analysis indicated that patients treated with H2A, rather than those on PPI, supported the burden of this risk. Similar findings applied for the risk of infectious mortality. On the contrary, we were not able to detect any association among the study variables, on one side, and the general risks of peritonitis or mortality, on the other. Treatment with IGAS associates increased incidences of enteric peritonitis and infectious mortality, among patients on chronic PD. The association is clear in the case of H2A but less consistent in the case of PPI. Our results support the convenience of preferring PPI to H2A, for gastric acid inhibition in PD patients.

  10. Tolerance of banana for fusarium wilt is associated with early H 2 O ...

    African Journals Online (AJOL)

    Production of O2•− , H2O2 and MDA, as well as changes in enzyme activities, and transcript levels of SOD and CAT in root extracts were monitored every 24 h over 4 days. The histochemical location of H2O2 was also detected. In the resistant iso-line, the accumulation of O2•− and H2O2, and the activation of SOD occurred ...

  11. A novel sandwich-type polyoxometalate compound with visible-light photocatalytic H2 evolution activity.

    Science.gov (United States)

    Zhang, Zhenyu; Lin, Qipu; Zheng, Shou-Tian; Bu, Xianhui; Feng, Pingyun

    2011-04-07

    A tin(II) tungstosilicate derivative K(11)H[Sn(4)(SiW(9)O(34))(2)]·25H(2)O with four sandwiched Sn(2+) cations was prepared by reaction of SnCl(2), KCl and Na(10)[α-SiW(9)O(34)]·xH(2)O. Visible-light photocatalytic H(2) evolution activity was observed with Pt nanoparticles as co-catalyst and methanol as sacrificial agent.

  12. Comparison of genes required for H2O2 resistance in Streptococcus gordonii and Streptococcus sanguinis

    Science.gov (United States)

    Xu, Yifan; Itzek, Andreas

    2014-01-01

    Hydrogen peroxide (H2O2) is produced by several members of the genus Streptococcus mainly through the pyruvate oxidase SpxB under aerobic growth conditions. The acute toxic nature of H2O2 raises the interesting question of how streptococci cope with intrinsically produced H2O2, which subsequently accumulates in the microenvironment and threatens the closely surrounding population. Here, we investigate the H2O2 susceptibility of oral Streptococcus gordonii and Streptococcus sanguinis and elucidate potential mechanisms of how they protect themselves from the deleterious effect of H2O2. Both organisms are considered primary colonizers and occupy the same intraoral niche making them potential targets for H2O2 produced by other species. We demonstrate that S. gordonii produces relatively more H2O2 and has a greater ability for resistance to H2O2 stress. Functional studies show that, unlike in Streptococcus pneumoniae, H2O2 resistance is not dependent on a functional SpxB and confirms the important role of the ferritin-like DNA-binding protein Dps. However, the observed increased H2O2 resistance of S. gordonii over S. sanguinis is likely to be caused by an oxidative stress protection machinery present even under anaerobic conditions, while S. sanguinis requires a longer period of time for adaptation. The ability to produce more H2O2 and be more resistant to H2O2 might aid S. gordonii in the competitive oral biofilm environment, since it is lower in abundance yet manages to survive quite efficiently in the oral biofilm. PMID:25280752

  13. Absolute linestrengths in the H2O2 nu6 band

    Science.gov (United States)

    May, Randy D.

    1991-01-01

    Absolute linestrengths at 295 K have been measured for selected lines in the nu6 band of H2O2 using a tunable diode-laser spectrometer. H2O2 concentrations in a flowing gas mixture were determined by ultraviolet (uv) absorption at 254 nm using a collinear infrared (ir) and uv optical arrangement. The measured linestrengths are approx. 60 percent larger than previously reported values when absorption by hot bands in H2O2 is taken into account.

  14. Vibrational relaxation of the H2O bending mode in liquid water.

    Science.gov (United States)

    Larsen, Olaf F A; Woutersen, Sander

    2004-12-22

    We have studied the vibrational relaxation of the H(2)O bending mode in an H(2)O:HDO:D(2)O isotopic mixture using infrared pump-probe spectroscopy. The transient spectrum and its delay dependence reveal an anharmonic shift of 55+/-10 cm(-1) for the H(2)O bending mode, and a value of 400+/-30 fs for its vibrational lifetime. (c) 2004 American Institute of Physics.

  15. Non-LTE H2+ as the source of missing opacity in the solar atmosphere

    Science.gov (United States)

    Swamy, K. S. K.; Stecher, T. P.

    1974-01-01

    The population of the various vibrational levels of the H2+ molecule has been calculated from the consideration of formation and destruction mechanisms. The resulting population is used in calculating the total absorption due to H2+ and is compared with the other known sources of opacity at several optical depths of the solar atmosphere. It is shown that the absorption due to H2+ can probably account for the missing ultraviolet opacity in the solar atmosphere.

  16. Effect of H2S on SO2-depolarised water electrolysis

    OpenAIRE

    Krüger, Andries J.; Krieg, Henning M.; Bessarabov, Dmitri

    2015-01-01

    The performance of a PEM SO2 electrolyser, used for the production of H2 gas and liquid H2SO4, was evaluated when the feed was contaminated with hydrogen sulfide. Transient voltage response at constant current density and polarisation curves showed a decrease in operating efficiency over time for all H2S concentrations tested. Electrochemical impedance spectroscopy (EIS) was applied to separate and quantify the membrane resistance, charge resistance and mass transport limitations to evaluate ...

  17. Synthesis of CuO nanoflower and its application as a H2O2 sensor

    Indian Academy of Sciences (India)

    Administrator

    Abstract. CuO three-dimensional (3D) flower-like nanostructures were successfully synthesized by a simple method at 100°C with Cu(NO3)2⋅3H2O and NH3⋅H2O for 6 h in the absence of any additives. We found that. NH3⋅H2O amount was critical for CuO morphology evolution. The phase analysis was carried out using ...

  18. Algorithms to Solve Stochastic H2/H∞ Control with State-Dependent Noise

    Directory of Open Access Journals (Sweden)

    Ming Gao

    2014-01-01

    Full Text Available This paper is concerned with the algorithms which solve H2/H∞ control problems of stochastic systems with state-dependent noise. Firstly, the algorithms for the finite and infinite horizon H2/H∞ control of discrete-time stochastic systems are reviewed and studied. Secondly, two algorithms are proposed for the finite and infinite horizon H2/H∞ control of continuous-time stochastic systems, respectively. Finally, several numerical examples are presented to show the effectiveness of the algorithms.

  19. Optimal laser pulse design for transferring the coherent nuclear wave packet of H$_2^+$

    OpenAIRE

    Zhang, Jun; He, Feng

    2013-01-01

    Within the Franck-Condon approximation, the single ionization of H$_2$ leaves H$_2^+$ in a coherent superposition of 19 nuclear vibrational states. We numerically design an optimal laser pulse train to transfer such a coherent nuclear wave packet to the ground vibrational state of H$_2^+$. The simulation results show that the population of the ground state after the transfer is more than 91%. Frequency analysis of the designed optimal pulse reveals that the transfer principle is mainly an ant...

  20. Test summary for advanced H2 cycle NI-CD cell

    Science.gov (United States)

    Miller, Lee

    1987-01-01

    To improve operational tolerances and mass, the H2 gas recombination design provisions of the Ni-H2 system were incorporated into the sealed Ni-Cd system. Produced is a cell design capable of operating on the H2 cycle versus the normal O2 cycle. Three test cells have now completed approximately 4,330 LEO (90 minute) cycles at 20 percent depth of discharge (DOD). Performance remains stable although one cell exhibited a temporary pressure anomaly.

  1. Dissociative ionization of H2 and D2 by electron impact near threshold

    NARCIS (Netherlands)

    Boesten, L.G.J.; Heideman, H.G.M.

    We have studied the dissciative ionization of H2 and D2 by electron impact. It is found that in the vicinity of the 2Σ+g dissociation threshold of H+2 (18.08 eV) a significant fraction of the produced protons originates from the process e + H2 → H− + H+ + e (threshold at 17.34 eV). Similar results

  2. The incidence of apoptotic bodies in membrana granulosa can predict prognosis of ova from patients participating in in vitro fertilization programs.

    Science.gov (United States)

    Nakahara, K; Saito, H; Saito, T; Ito, M; Ohta, N; Takahashi, T; Hiroi, M

    1997-08-01

    To investigate the relationship between the incidence of apoptotic bodies in membrana granulosa and follicular steroid concentrations in human follicles. Case-controlled prospective study for 132 individual follicles. Procedures were performed in Yamagata University Hospital. Thirty-six normo-ovulatory women with tubal infertility underwent ovulation induction for IVF-ET with a conventional hyperstimulation method. Patients underwent follicle aspiration after the administration of hCG. The nuclei of recovered granulosa cells were examined by fluorescence microscopy, and the incidence of apoptotic bodies was tabulated. Intrafollicular steroids were evaluated mainly by RIA. These data were analyzed with respect to oocyte-retrieval, oocyte maturity, fertilization, and embryo quality. Membrana granulosa cells in the follicles from which oocytes were subsequently fertilized showed a significantly lower incidence of apoptotic bodies than those in follicles from which the oocytes did not fertilize. Membrana granulosa cells in the follicles from which oocytes were developed into good quality showed a significantly lower incidence of apoptotic bodies than those in the follicles from which oocytes developed into fair and poor quality. The incidence of apoptotic bodies was significantly higher in the mural granulosa cell region than in the cumulus cell region in most cases. Intrafollicular E2, P, and free T levels were not different between the oocyte groups. These results indicate that lower incidence of apoptotic bodies in individual follicles is associated with better outcomes for oocytes. Also, mural granulosa cells and cumulus cell in each follicle may show differentiation during follicular maturation.

  3. The radiation stability of the RNA base uracil in H2O-ice and CO2-ice: in-situ laboratory measurements with applications to comets, Europa, and Mars

    Science.gov (United States)

    Gerakines, Perry A.; Frail, Sarah; Hudson, Reggie L.

    2017-10-01

    Planetary bodies of astrobiological interest, such as Mars, are often exposed to harsh incident radiation, which will influence the times that molecules can survive on them. Some or all of these bodies may well contain biologically-important organic molecules, some may even have supported life at some point in their history, and some may support life today. Future searches for organic molecules likely will include sampling the martian subsurface or a cometary surface sample return mission, where organics may be frozen in ices dominated by either H2O or CO2, which provide some protection from ionizing radiation.Recently, our research group has published studies of the radiation stability of amino acids, with a focus on glycine - in both undiluted form and in mixtures with H2O and CO2. Here, we present a similar study that focuses on the radiation-chemical kinetics of the RNA base uracil. We compare results for uracil decay for dilution in both H2O and CO2 ices. Moreover, we compare these new results with those for glycine. For each sample, we measured uracil’s destruction rate constant and half-life dose due to irradiation by 0.9-MeV protons. All measurements were made in situ at the temperature of irradiation using IR spectroscopy. Trends with dilution (up to ~300:1) and temperature (up to ~150 K) are considered, and results are discussed in the context of icy planetary surfaces.Acknowledgment: Our work is supported in part by the NASA Emerging Worlds Program and by the NASA Astrobiology Institute through the Goddard Center for Astrobiology.

  4. The geochemistry and sequestration of H2S into the geothermal system at Hellisheidi, Iceland.

    OpenAIRE

    Stefánsson, A.

    2010-01-01

    The geochemistry and mineralization of H2S in the geothermal system hosted by basaltic rock formation at Hellisheidi, SW Iceland, was studied. Injection of mixtures of H2S with geothermal waste water and condensed steam into the N230 °C geothermal aquifer is planned, where H2S will hopefully be removed in the form of sulphides. The natural H2S concentrations in the aquifer average 130 ppm. They are considered to be controlled by close approach to equilibrium with pyrite, pyrrh...

  5. Human Milk H2O2 content: Does it benefit preterm infants?

    Science.gov (United States)

    Cieslak, Monika; Ferreira, Cristina H F; Shifrin, Yulia; Pan, Jingyi; Belik, Jaques

    2017-11-22

    Human milk has a high content of the antimicrobial compound hydrogen peroxide (H2O2). As opposed to healthy full-term infants, preterm neonates are fed previously expressed and stored maternal milk. These practices may favor H2O2 decomposition, thus limiting its potential benefit to preterm infants. The goal of this study was to evaluate the factors responsible for H2O2 generation and degradation in breastmilk. Human donors' and rat milk, along with rat mammary tissue were evaluated. The role of oxytocin and xanthine oxidase on H2O2 generation, its pH-dependent stability, as well as its degradation via lactoperoxidase and catalase were measured in milk. Breast tissue xanthine oxidase is responsible for the H2O2 generation and its milk content is dependent on oxytocin stimulation. Stability of the human milk H2O2 content is pH dependent and greatest in the acidic range. Complete H2O2 degradation occurs when human milk is maintained, longer than 10 min, at room temperature and this process is suppressed by lactoperoxidase and catalase inhibition. Fresh breastmilk H2O2 content is labile and quickly degrades at room temperature. Further investigation on breastmilk handling techniques to preserve its H2O2 content, when gavage-fed to preterm infants is warranted.Pediatric Research accepted article preview online, 22 November 2017. doi:10.1038/pr.2017.303.

  6. Force-Induced H2S by PDLSCs Modifies Osteoclastic Activity during Tooth Movement.

    Science.gov (United States)

    Liu, F; Wen, F; He, D; Liu, D; Yang, R; Wang, X; Yan, Y; Liu, Y; Kou, X; Zhou, Y

    2017-06-01

    Hydrogen sulfide (H 2 S), a gasotransmitter, has been recently linked to mesenchymal stem cell (MSC) function and bone homeostasis. Periodontal ligament stem cells (PDLSCs) are the main MSCs in PDL, which respond to mechanical force to induce physiological activities during orthodontic tooth movement (OTM). However, it is unknown whether mechanical force might induce endogenous H 2 S production by PDLSCs to regulate alveolar bone homeostasis. Here, we used a mouse OTM model to demonstrate that orthodontic force-induced endogenous H 2 S production in PDL tissue was associated with macrophage accumulation and osteoclastic activity in alveolar bone. Then, we showed that mechanical force application induced cystathionine β-synthase (CBS) expression and endogenous H 2 S production by PDLSCs. Moreover, blocking endogenous H 2 S or systemically increasing H 2 S levels could decrease or enhance force-induced osteoclastic activities to control tooth movement. We further revealed how force-induced H 2 S production by PDLSCs contributed to the secretion of monocyte chemoattractant protein-1 (MCP-1) and the expression of receptor activator of nuclear factor-κB ligand/osteoprotegerin (RANKL/OPG) system by PDLSCs. The secretion and expression of these factors controlled macrophage migration and osteoclast differentiation. This study demonstrated that PDLSCs produced H 2 S to respond to and transduce force signals. Force-induced gasotransmitter H 2 S production in PDLSCs therefore regulated osteoclastic activities in alveolar bone and controlled the OTM process through the MCP-1 secretion and RANKL/OPG system.

  7. Massive Star Formation, Outflows, and Anomalous H2 Emission in Mol 121 (IRAS 20188+3928)

    Science.gov (United States)

    Wolf-Chase, Grace; Arvidsson, Kim; Smutko, Michael; Sherman, Reid

    2013-01-01

    We have discovered 12 new molecular hydrogen emission-line objects (MHOs) in the vicinity of the candidate massive young stellar object Mol 121, in addition to five that were previously known. H2 2.12 μm/H2 2.25 μm flux ratios indicate another region dominated by fluorescence from a photodissociation region, and one region that displays an anomalously low H2 2.12 μm/H2 2.25 μm flux ratio (young stellar objects embedded in cores that are likely to be in different evolutionary stages.

  8. UV Raman spectroscopy of H2-air flames excited with a narrowband KrF laser

    Science.gov (United States)

    Shirley, John A.

    1990-01-01

    Raman spectra of H2 and H2O in flames excited by a narrowband KrF excimer laser are reported. Observations are made over a porous-plug, flat-flame burner reacting H2 in air, fuel-rich with nitrogen dilution to control the temperature, and with an H2 diffusion flame. Measurements made from UV Raman spectra show good agreement with measurements made by other means, both for gas temperature and relative major species concentrations. Laser-induced fluorescence interferences arising from OH and O2 are observed in emission near the Raman spectra. These interferences do not preclude Raman measurements, however.

  9. RNaseH2 mutants that cause Aicardi-Goutieres syndrome are active nucleases

    OpenAIRE

    Perrino, Fred W.; Harvey, Scott; Shaban, Nadine M.; Hollis, Thomas

    2008-01-01

    Mutations in the genes encoding the RNaseH2 and TREX1 nucleases have been identified in patients with Aicardi-Goutieres syndrome (AGS). To determine if the AGS RNaseH2 mutations result in the loss of nuclease activity, the human wild-type RNaseH2 and four mutant complexes that constitute the majority of mutations identified in AGS patients have been prepared and tested for ribonuclease H activity. The heterotrimeric structures of the mutant RNaseH2 complexes are intact. Furthermore, the ribon...

  10. Impact of a future H2 transportation on atmospheric pollution in Europe

    Science.gov (United States)

    Popa, M. E.; Segers, A. J.; Denier van der Gon, H. A. C.; Krol, M. C.; Visschedijk, A. J. H.; Schaap, M.; Röckmann, T.

    2015-07-01

    Hydrogen (H2) is being explored as a fuel for passenger vehicles; it can be used in fuel cells to power electric motors or burned in internal combustion engines. In order to evaluate the potential influence of a future H2-based road transportation on the regional air quality in Europe, we implemented H2 in the atmospheric transport and chemistry model LOTOS-EUROS. We simulated the present and future (2020) air quality, using emission scenarios with different proportions of H2 vehicles and different H2 leakage rates. The reference future scenario does not include H2 vehicles, and assumes that all present and planned European regulations for emissions are fully implemented. We find that, in general, the air quality in 2020 is significantly improved compared to the current situation in all scenarios, with and without H2 cars. In the future scenario without H2 cars, the pollution is reduced due to the strict European regulations: annually averaged CO, NOx and PM2.5 over the model domain decrease by 15%, 30% and 20% respectively. The additional improvement brought by replacing 50% or 100% of traditionally-fueled vehicles by H2 vehicles is smaller in absolute terms. If 50% of vehicles are using H2, the CO, NOx and PM2.5 decrease by 1%, 10% and 1% respectively, compared to the future scenario without H2 cars. When all vehicles run on H2, then additional decreases in CO, NOx and PM2.5 are 5%, 40%, and 5% relative to the no-H2 cars future scenario. Our study shows that H2 vehicles may be an effective pathway to fulfill the strict future EU air quality regulations. O3 has a more complicated behavior - its annual average decreases in background areas, but increases in the high-NOx area in western Europe, with the decrease in NOx. A more detailed analysis shows that the population exposure to high O3 levels decreases nevertheless. In all future scenarios, traffic emissions account for only a small proportion of the total anthropogenic emissions, thus it becomes more important

  11. H2O2-triggered bubble generating antioxidant polymeric nanoparticles as ischemia/reperfusion targeted nanotheranostics.

    Science.gov (United States)

    Kang, Changsun; Cho, Wooram; Park, Minhyung; Kim, Jinsub; Park, Sanghoon; Shin, Dongho; Song, Chulgyu; Lee, Dongwon

    2016-04-01

    Overproduction of reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) leads to oxidative stress, causing inflammation and cellular damages and death. H2O2 is one of the most stable and abundant ROS and H2O2-mediated oxidative stress is considered as a key mediator of cellular and tissue damages during ischemia/reperfusion (I/R) injury. Therefore, H2O2 could hold tremendous potential as a diagnostic biomarker and therapeutic target for oxidative stress-associated inflammatory conditions such as I/R injury. Here, we report a novel nanotheranostic agent that can express ultrasound imaging and simultaneous therapeutic effects for hepatic I/R treatment, which is based on H2O2-triggered CO2-generating antioxidant poly(vanillin oxalate) (PVO). PVO nanoparticles generate CO2 through H2O2-triggered oxidation of peroxalate esters and release vanillin, which exerts antioxidant and anti-inflammatory activities. PVO nanoparticles intravenously administrated remarkably enhanced the ultrasound signal in the site of hepatic I/R injury and also effectively suppressed the liver damages by inhibiting inflammation and apoptosis. To our best understanding, H2O2-responsive PVO is the first platform which generates bubbles to serve as ultrasound contrast agents and also exerts therapeutic activities. We therefore anticipate that H2O2-triggered bubble-generating antioxidant PVO nanoparticles have great potential for ultrasound imaging and therapy of H2O2-associated diseases. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Explosion Power and Pressure Desensitization Resisting Property of Emulsion Explosives Sensitized by MgH2

    Science.gov (United States)

    Cheng, Yangfan; Ma, Honghao; Liu, Rong; Shen, Zhaowu

    2014-07-01

    Due to low detonation power and pressure desensitization problems that traditional emulsion explosives encounter in utilization, a hydrogen-based emulsion explosives was devised. This type of emulsion explosives is sensitized by hydrogen-containing material MgH2, and MgH2 plays a double role as a sensitizer and an energetic material in emulsion explosives. Underwater explosion experiments and shock wave desensitization experiments show that an MgH2 emulsion explosives has excellent detonation characteristics and is resistant to pressure desensitization. The pressure desensitization-resistant mechanism of MgH2 emulsion explosives was investigated using scanning electron microscopy.

  13. Extreme deuterium enrichment in stratospheric hydrogen and the global atmospheric budget of H2.

    Science.gov (United States)

    Rahn, Thom; Eiler, John M; Boering, Kristie A; Wennberg, Paul O; McCarthy, Michael C; Tyler, Stanley; Schauffler, Sue; Donnelly, Stephen; Atlas, Elliot

    2003-08-21

    Molecular hydrogen (H2) is the second most abundant trace gas in the atmosphere after methane (CH4). In the troposphere, the D/H ratio of H2 is enriched by 120 per thousand relative to the world's oceans. This cannot be explained by the sources of H2 for which the D/H ratio has been measured to date (for example, fossil fuels and biomass burning). But the isotopic composition of H2 from its single largest source--the photochemical oxidation of methane--has yet to be determined. Here we show that the D/H ratio of stratospheric H2 develops enrichments greater than 440 per thousand, the most extreme D/H enrichment observed in a terrestrial material. We estimate the D/H ratio of H2 produced from CH4 in the stratosphere, where production is isolated from the influences of non-photochemical sources and sinks, showing that the chain of reactions producing H2 from CH4 concentrates D in the product H2. This enrichment, which we estimate is similar on a global average in the troposphere, contributes substantially to the D/H ratio of tropospheric H2.

  14. Detailed H2 and CO Electrochemistry for a MEA Model Fueled by Syngas

    KAUST Repository

    Lee, W. Y.

    2015-07-17

    © The Electrochemical Society. SOFCs can directly oxidize CO in addition to H2, which allows them to be coupled to a gasifier. Many membrane-electrode-assembly (MEA) models neglect CO electrochemistry due to sluggish kinetics and the water-gas-shift reaction, but CO oxidation may be important for high CO-content syngas. The 1D-MEA model presented here incorporates detailed mechanisms for both H2 and CO oxidation, individually fitted to experimental data. These mechanisms are then combined into a single model, which provides a good fit to experimental data for H2/CO mixtures. Furthermore, the model fits H2/CO data best when a single chargetransfer step in the H2 mechanism is assumed to be rate-limiting for all current densities. This differs from the result for H2/H2O mixtures, where H2 adsorption becomes rate-limiting at high current densities. These results indicate that CO oxidation cannot be neglected in MEA models running on CO-rich syngas, and that CO oxidation can alter the H2 oxidation mechanism.

  15. Do We Understand the Environmental Impacts of an H2 Economy?

    Science.gov (United States)

    Prather, M. J.

    2004-12-01

    The promise of a clean, hydrogen (H2)-fueled transportation sector has been waved in front of the nation by the current administration, the governor of California, and the technologists. A 2004 NAS report on "The Hydrogen Economy" was prepared by the economists and engineers, remarkably lacking any atmospheric scientists or biogeochemists who understand the natural cycle of H2. It is surprising that all of these groups examining a hydrogen economy are secure in the belief that H2 is a pure fuel, safe and harmless to the environment. A thorough well-to-wheel analysis as envisaged by the NAS report is needed to evaluate the environmental costs/benefits of a hydrogen economy (e.g., the energy source for producing H2, the distribution system), but it needs also to include our knowledge of the biogeochemical cycling of H2 in the atmosphere (0.5 ppm or about 175 Tg) and how it might be perturbed. This brief review of the science examines what controls the atmospheric abundance of H2 and how the chemistry of H2 impacts the climate and global air quality. Recent work on hydrogen isotopes, global modeling of sources and sinks, and the stratospheric and climate connections, enables us to more clearly define the budget and impacts of H2, and to place reasonable bounds on the environmental impacts - provided we understand the possible future emissions of H2 and of related direct and indirect greenhouse gases.

  16. Turn-on fluorescence detection of H2O2 and TATP.

    Science.gov (United States)

    Germain, Meaghan E; Knapp, Michael J

    2008-11-03

    Peroxide-based explosives, like triacetone triperoxide (TATP), are important targets for detection because of their broad use in improvised explosives but pose challenges. We report a highly sensitive turn-on fluorescence detection for H2O2 and organic peroxides, including TATP. The detection strategy relies on oxidative deboronation to unmask H2Salen, which subsequently binds Zn(2+) to form fluorescent Zn(Salen). Sensitivity is excellent, with detection limits below 10 nM for H2O2, TATP, and benzoyl peroxide. In addition, acid treatment is necessary to sense TATP, suggesting the potential to discriminate between H2O2 and TATP based upon minimal sample pretreatment.

  17. Synthesis, X-ray crystal structure, and EPR study of [Na(H 2O) 2] 2[VO(H 2O) 5][SiW 12O 40]·4H 2O

    Science.gov (United States)

    Tézé, André; Marchal-Roch, Catherine; So, Hyunsoo; Fournier, Michel; Hervé, Gilbert

    2001-03-01

    The vanadyl salt [Na(H 2O) 2] 2[VO(H 2O) 5][SiW 12O 40]·4H 2O has been synthesized in mild conditions by cationic exchanges from dodecasilicotungstic acid. Structural determination and EPR study have been achieved on single crystals. They are tetragonal, space group P4/ n with a=14.7759(1), c=10.4709(2) Å, V=2286(1) Å 3 and Z=2. A three-dimensional framework built from Keggin anions [SiW 12O 40] 4- linked by sodium cations in (110) and ( 1 1¯0 ) planes generates channels along the c axis in which are localized aquo vanadyl complexes [VO(H 2O) 5] 2+ and water molecules. Single crystal EPR spectra show eight hyperfine lines of the vanadium atom ( I=7/2) which are split into 1:2:1 pattern when the magnetic field is parallel to the c axis. The triplet pattern may be attributed to weak dipolar interactions between the nearest-neighbor vanadium atoms which are 10.47 Å apart in the infinite chain. A ring model was used to simulate the spectrum, and a very small antiferromagnetic exchange interaction was determined accurately . The EPR parameters determined are gx= gy=1.980, gz=1.9336, Ax= Ay=0.0072 cm -1, and Az=0.01805 cm -1, J=-0.00025 cm -1.

  18. Rate Controlling Step in the Reduction of Iron Oxides; Kinetics and Mechanism of Wüstite-Iron Step in H2, CO and H2/CO Gas Mixtures

    Science.gov (United States)

    El-Geassy, Abdel-Hady A.

    2017-09-01

    Wüstite (W1 and W2) micropellets (150-50 μm) were prepared from the reduction of pure Fe2O3 and 2.1% SiO2-doped Fe2O3 in 40%CO/CO2 gas mixture at 1000°C which were then isothermally reduced in H2, CO and H2/CO gas mixtures at 900-1100°C. The reduction reactions was followed by Thermogravimetric Analysis (TG) technique. The effect of gas composition, gas pressure and temperature on the rate of reduction was investigated. The different phases formed during the reduction were chemically and physically characterized. In SiO2-doped wüstite, fayalite (Fe2SiO3) was identified. At the initial reduction stages, the highest rate was obtained in H2 and the lowest was in CO gas. In H2/CO gas mixtures, the measured rate did not follow a simple additive equation. The addition of 5% H2 to CO led to a measurable increase in the rate of reduction compared with that in pure CO. Incubation periods were observed at the early reduction stages of W1 in CO at lower gas pressure (reaction rate minimum was detected in H2 and H2-rich gas mixtures at 925-950°C. The influence of addition of H2 to CO or CO to H2 on the reduction reactions, nucleation and grain growth of iron was intensively studied. Unlike in pure wüstite, the presence of fayalite enhances the reduction reactions with CO and CO-rich gas mixtures. The chemical reaction equations of pure wüstite with CO are given showing the formation of carbonyl-like compound [Fem(CO2)n]*. The apparent activation energy values, at the initial stages, ranged from 53.75 to 133.97 kJ/mole indicating different reaction mechanism although the reduction was designed to proceed by the interfacial chemical reaction.

  19. The Water Abundance behind Interstellar Shocks: Results from Herschel/PACS and Spitzer/IRS Observations of H2O, CO, and H2

    Science.gov (United States)

    Neufeld, David A.; Gusdorf, Antoine; Güsten, Rolf; Herczeg, Greg J.; Kristensen, Lars; Melnick, Gary J.; Nisini, Brunella; Ossenkopf, Volker; Tafalla, Mario; van Dishoeck, Ewine F.

    2014-02-01

    We have investigated the water abundance in shock-heated molecular gas, making use of Herschel measurements of far-infrared (IR) CO and H2O line emissions in combination with Spitzer measurements of mid-IR H2 rotational emissions. We present far-IR line spectra obtained with Herschel's Photodetector Array Camera and Spectrometer instrument in range spectroscopy mode toward two positions in the protostellar outflow NGC 2071 and one position each in the supernova remnants W28 and 3C391. These spectra provide unequivocal detections, at one or more positions, of 12 rotational lines of water, 14 rotational lines of CO, 8 rotational lines of OH (4 lambda doublets), and 7 fine-structure transitions of atoms or atomic ions. We first used a simultaneous fit to the CO line fluxes, along with H2 rotational line fluxes measured previously by Spitzer, to constrain the temperature and density distribution within the emitting gas; we then investigated the water abundances implied by the observed H2O line fluxes. The water line fluxes are in acceptable agreement with standard theoretical models for nondissociative shocks that predict the complete vaporization of grain mantles in shocks of velocity v ~ 25 km s-1, behind which the characteristic gas temperature is ~1300 K and the H2O/CO ratio is 1.2

  20. Reactions of H+(pyridinem(H2On and H+(NH31(pyridinem(H2On with NH3: experiments and kinetic modelling

    Directory of Open Access Journals (Sweden)

    E. Uggerud

    2012-03-01

    Full Text Available Reactions between pyridine containing water cluster ions, H+(pyridine1(H2On, H+(pyridine2(H2On and H+(NH31(pyridine1(H2On (n up to 15 with NH3 have been studied experimentally using a quadrupole time-of-flight mass spectrometer. The product ions in the reaction between H+(pyridinem(H2On (m = 1 to 2 and NH3 have been determined for the first time. It is found that the reaction mainly leads to cluster ions of the form H+(NH31(pyridinem(H2On-x, with x = 1 or 2 depending on the initial size of the reacting cluster ion. For a given number of water molecules (from 5 to 15 in the cluster ion, rate coefficients are found to be slightly lower than those for protonated pure water clusters reacting with ammonia. The rate coefficients obtained from this study are used in a kinetic cluster ion model under tropospheric conditions. The disagreement between ambient ground level measurements and previous models are discussed in relation to the results from our model and future experimental directions are suggested.

  1. VizieR Online Data Catalog: Raman scattering cross sections for H2 (Oklopcic+,

    Science.gov (United States)

    Oklopcic, A.; Hirata, C. M.; Heng, K.

    2017-02-01

    An important source of opacity in exoplanet atmospheres at short visible and near-UV wavelengths is Rayleigh scattering of light on molecules. It is accompanied by a related, albeit weaker process-Raman scattering. We analyze the signatures of Raman scattering imprinted in the reflected light and the geometric albedo of exoplanets, which could provide information about atmospheric properties. Raman scattering affects the geometric albedo spectra of planets in the following ways. First, it causes filling-in of strong absorption lines in the incident radiation, thus producing sharp peaks in the albedo. Second, it shifts the wavelengths of spectral features in the reflected light causing the so-called Raman ghost lines. Raman scattering can also cause a broadband reduction of the albedo due to wavelength shifting of a stellar spectrum with red spectral index. Observing the Raman peaks in the albedo could be used to measure the column density of gas, thus providing constraints on the presence of clouds in the atmosphere. Observing the Raman ghost lines could be used to spectroscopically identify the main scatterer in the atmosphere, even molecules like H2 or N2, which do not have prominent spectral signatures in the optical wavelength range. If detected, ghost lines could also provide information about the temperature of the atmosphere. In this paper, we investigate the effects of Raman scattering in hydrogen- and nitrogen-dominated atmospheres. We analyze the feasibility of detecting the signatures of Raman scattering with the existing and future observational facilities, and of using these signatures as probes of exoplanetary atmospheres. (1 data file).

  2. Incident reporting.

    Science.gov (United States)

    Wilson, J

    Healthcare delivery is a risky business. People view the NHS in the same light as other commercial businesses such as the hotel, retail and airline industries. The White Paper 'The New NHS: Modern, Dependable' (Secretary of State for Health, 1997) places statutory responsibilities on managers and clinicians to provide a quality service and to have accountability for clinical governance and performance management. Quality and risk are two sides of the same coin, i.e. if you have good quality you have low risk, and this firmly supports the clinical effectiveness agenda. Healthcare organizations in all sectors of care delivery need to demonstrate their high levels of achievement and commitment to continuous quality improvements. Risk management is a process for identifying, assessing and evaluating risks which have adverse effects on the quality, safety and effectiveness of service delivery, and taking positive action to eliminate or reduce them. Having an open, honest and blame-free organization which is open to improving processes and systems of care is a big step towards having staff who are committed to quality and getting things right. Near-miss, incident and indicator recording and reporting are cornerstones of any quality and risk management system.

  3. "Plug-and-Play" potentials: Investigating quantum effects in (H2)2-Li+-benzene

    Science.gov (United States)

    D'Arcy, Jordan H.; Kolmann, Stephen J.; Jordan, Meredith J. T.

    2015-08-01

    Quantum and anharmonic effects are investigated in (H2)2-Li+-benzene, a model for hydrogen adsorption in metal-organic frameworks and carbon-based materials, using rigid-body diffusion Monte Carlo (RBDMC) simulations. The potential-energy surface (PES) is calculated as a modified Shepard interpolation of M05-2X/6-311+G(2df,p) electronic structure data. The RBDMC simulations yield zero-point energies (ZPE) and probability density histograms that describe the ground-state nuclear wavefunction. Binding a second H2 molecule to the H2-Li+-benzene complex increases the ZPE of the system by 5.6 kJ mol-1 to 17.6 kJ mol-1. This ZPE is 42% of the total electronic binding energy of (H2)2-Li+-benzene and cannot be neglected. Our best estimate of the 0 K binding enthalpy of the second H2 to H2-Li+-benzene is 7.7 kJ mol-1, compared to 12.4 kJ mol-1 for the first H2 molecule. Anharmonicity is found to be even more important when a second (and subsequent) H2 molecule is adsorbed; use of harmonic ZPEs results in significant error in the 0 K binding enthalpy. Probability density histograms reveal that the two H2 molecules are found at larger distance from the Li+ ion and are more confined in the θ coordinate than in H2-Li+-benzene. They also show that both H2 molecules are delocalized in the azimuthal coordinate, ϕ. That is, adding a second H2 molecule is insufficient to localize the wavefunction in ϕ. Two fragment-based (H2)2-Li+-benzene PESs are developed. These use a modified Shepard interpolation for the Li+-benzene and H2-Li+-benzene fragments, and either modified Shepard interpolation or a cubic spline to model the H2-H2 interaction. Because of the neglect of three-body H2, H2, Li+ terms, both fragment PESs lead to overbinding of the second H2 molecule by 1.5 kJ mol-1. Probability density histograms, however, indicate that the wavefunctions for the two H2 molecules are effectively identical on the "full" and fragment PESs. This suggests that the 1.5 kJ mol-1 error is

  4. Why did you decide to become a Geoscience Major: A Critical Incident Study for the Development of Recruiting Programs for Inspiring Interests in the Geosciences Amongst Pre-College Students

    Science.gov (United States)

    Carrick, T. L.; Miller, K. C.; Levine, R.; Martinez-Sussmann, C.; Velasco, A. A.

    2011-12-01

    Anecdotally, it is often stated that the majority of students that enter the geosciences usually do so sometime after their initial entrance into college. With the objective of providing concrete and useful information for individuals developing programs for inspiring interest in the Geosciences amongst pre-college students and trying to increase the number of freshman Geoscience majors, we conducted a critical incident study. Twenty-two students, who were undergraduate or graduate Geoscience majors, were asked, "Why did you decide to major in the Geosciences?" in a series of interviews. Their responses were then used to identify over 100 critical incidents, each of which described a specific behavior that was causally responsible for a student's choice to major in Geoscience. Using these critical incidents, we developed a preliminary taxonomy that is comprised of three major categories: Informal Exposure to the Geosciences (e.g., outdoor experiences, family involvement), Formal Exposure to the Geosciences (e.g., academic experiences, program participation) and a Combined Informal and Formal Exposure (e.g., media exposure). Within these three main categories we identified thirteen subcategories. These categories and subcategories, describe, classify, and provide concrete examples of strategies that were responsible for geosciences career choices. As a whole, the taxonomy is valuable as a new, data-based guide for designing geosciences recruitment programs for the pre-college student population.

  5. Evaluating γH2AX in spermatozoa from male infertility patients.

    Science.gov (United States)

    Zhong, Hui-zhi; Lv, Fu-tong; Deng, Xue-lian; Hu, Ying; Xie, Dan-ni; Lin, Bin; Mo, Zeng-nan; Lin, Fa-quan

    2015-09-01

    To investigate whether γH2AX levels were different in the spermatozoa of healthy men compared with infertility patients, and to assess the possible correlations between γH2AX and conventional semen parameters and double-stranded breaks (DSBs) identified with the use of comet assay. Prospective study. Clinical laboratory. Semen from 100 male infertile patients and 100 healthy sperm donors. Human sperm samples were analyzed in terms of World Health Organization parameters. The γH2AX levels were detected by means of flow cytometry. DSBs of sperm were detected by means of comet assay. Morphology slides were made and the sperm morphology assessed according to strict criteria. Conventional semen analyses, γH2AX levels in sperm, DNA DSBs in sperm, and correlations among γH2AX, conventional semen analyses, and DSBs. Concentration, viability, motility, and normal sperm morphology were significantly lower in male infertility patients compared with healthy men. Also, γH2AX levels and the number of DSBs were significantly higher in the sperm of infertile subjects compared with healthy men. γH2AX levels correlated negatively with conventional semen parameters and positively with DSBs. A threshold γH2AX level of 18.55% was identified as a cutoff value to discriminate infertile subjects from fertile control subjects with a specificity of 86.0% and a sensitivity of 83.0%. The positive and negative predictive values of the 18.55% γH2AX threshold were high: 87.7% and 85.5%, respectively. γH2AX levels were higher in the sperm of male infertility patients than in healthy men. γH2AX levels in sperm, as evaluated with the use of flow cytometry, might be a useful biomarker for evaluating DSBs in human spermatozoa. Copyright © 2015 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  6. Dexmedetomidine attenuates H2O2-induced cell death in human osteoblasts.

    Science.gov (United States)

    Yoon, Ji-Young; Park, Jeong-Hoon; Kim, Eun-Jung; Park, Bong-Soo; Yoon, Ji-Uk; Shin, Sang-Wook; Kim, Do-Wan

    2016-12-01

    Reactive oxygen species play critical roles in homeostasis and cell signaling. Dexmedetomidine, a specific agonist of the α2-adrenoceptor, has been commonly used for sedation, and it has been reported to have a protective effect against oxidative stress. In this study, we investigated whether dexmedetomidine has a protective effect against H2O2-induced oxidative stress and the mechanism of H2O2-induced cell death in normal human fetal osteoblast (hFOB) cells. Cells were divided into three groups: control group-cells were incubated in normoxia without dexmedetomidine, hydrogen peroxide (H2O2) group-cells were exposed to H2O2 (200 µM) for 2 h, and Dex/H2O2 group-cells were pretreated with dexmedetomidine (5 µM) for 2 h then exposed to H2O2 (200 µM) for 2 h. Cell viability and apoptosis were evaluated. Osteoblast maturation was determined by assaying bone nodular mineralization. Expression levels of bone-related proteins were determined by western blot. Cell viability was significantly decreased in the H2O2 group compared with the control group, and this effect was improved by dexmedetomidine. The Hoechst 33342 and Annexin-V FITC/PI staining revealed that dexmedetomidine effectively decreased H2O2-induced hFOB cell apoptosis. Dexmedetomidine enhanced the mineralization of hFOB cells when compared to the H2O2 group. In western blot analysis, bone-related protein was increased in the Dex/H2O2 group. We demonstrated the potential therapeutic value of dexmedetomidine in H2O2-induced oxidative stress by inhibiting apoptosis and enhancing osteoblast activity. Additionally, the current investigation could be evidence to support the antioxidant potential of dexmedetomidine in vitro.

  7. H2O2 INDUCES DELAYED HYPEREXCITABILITY IN NUCLEUS TRACTUS SOLITARII NEURONS

    Science.gov (United States)

    Ostrowski, Tim D.; Hasser, Eileen M.; Heesch, Cheryl M.; Kline, David D.

    2014-01-01

    Hydrogen peroxide (H2O2) is a stable reactive oxygen species and potent neuromodulator of cellular and synaptic activity. Centrally, endogenous H2O2 is elevated during bouts of hypoxia-reoxygenation, a variety of disease states, and aging. The nucleus tractus solitarii (nTS) is the central termination site of visceral afferents for homeostatic reflexes and contributes to reflex alterations during these conditions. We determined the extent to which H2O2 modulates synaptic and membrane properties in nTS neurons in rat brainstem slices. Stimulation of the tractus solitarii (which contains the sensory afferent fibers) evoked synaptic currents that were not altered by 10 – 500 μM H2O2. However, 500 μM H2O2 modulated several intrinsic membrane properties of nTS neurons, including a decrease in input resistance, hyperpolarization of resting membrane potential (RMP) and action potential (AP) threshold (THR), and an initial reduction in AP discharge to depolarizing current. H2O2 increased conductance of barium-sensitive potassium currents, and block of these currents ablated H2O2-induced changes in RMP, input resistance and AP discharge. Following washout of H2O2 AP discharge was enhanced due to depolarization of RMP and a partially maintained hyperpolarization of THR. Hyperexcitability persisted with repeated H2O2 exposure. H2O2 effects on RMP and THR were ablated by intracellular administration of the antioxidant catalase, which was immunohistochemically identified in neurons throughout the nTS. Thus, H2O2 initially reduces excitability of nTS neurons that is followed by sustained hyperexcitability, which may play a profound role in cardiorespiratory reflexes. PMID:24397952

  8. Pushing the limits: detecting H2 emission from faint bipolar planetary nebulae in the IPHAS sample

    Science.gov (United States)

    Ramos-Larios, G.; Guerrero, M. A.; Sabin, L.; Santamaría, E.

    2017-09-01

    We have obtained deep narrowband images in the near-infrared H2 λ2.122 μm emission line for a sample of 15 faint Isaac Newton Telescope Photometric H α Survey (IPHAS) bipolar planetary nebulae (PNe) to search for molecular material. H2 emission is found in most of them (14 out of 15), mostly associated with rings at their equatorial regions and with their bipolar lobes. These detections add to the high occurrence of H2 emission among bipolar PNe reported in previous works, resulting from the large reservoir of molecular material in these sources and the suitable excitation conditions for H2 emission. The correlation between detailed bipolar morphology and H2 luminosity is also confirmed: bipolar PNe with broad equatorial rings (R-BPNe) have almost no continuum emission, are H2 brighter and have larger H2/Br γ line ratio than bipolar PNe with pinched equatorial waists (W-BPNe). The origin of this dichotomy is unclear. The larger size and age of R-BPNe are consistent with shock excitation of H2, whereas ultraviolet pumping is most likely the excitation mechanism in the smaller and younger W-BPNe, which would explain their lower H2 luminosity. Although both types of bipolar PNe seem to proceed from the same progenitor population, this does not imply that R-BPNe descend from W-BPNe. Otherwise, we note that some of the H2-weak bipolar PNe harbor post-common envelope binary systems and symbiotic stars. Finally, we suggest that the long-living H2 emission from R-BPNe arises from a discrete distribution of compact knots embedded within the ionized gas at the equatorial region.

  9. Trend in H2S Biology and Medicine Research—A Bibliometric Analysis

    Directory of Open Access Journals (Sweden)

    Guangdong Yang

    2017-11-01

    Full Text Available The biological and medical importance of hydrogen sulfide (H2S has been recognized for decades. The aim of this bibliometric study is to analyze the quantity and quality of publications in H2S biology and medicine (H2SBM based on the databases of Web of Science and Google Scholar. A total of 5881 publications published between 1990 and 2016 were analyzed. The number of H2SBM papers published before 2004 was below 100 annually, but thereafter this number rapidly increased and peaked in 2015 with more than 7-fold increase. All publications related to H2SBM research achieved a total h-index of 136 and were cited 123,074 times. The most published disciplines in H2S biomedicine research were the cardiovascular system (8.5%, neuroscience (6.5%, and gastroenterology hepatology (4.7%. The country with the greatest number of publications in the H2SBM research field was the USA with 1765 (30.0% publications, followed by China with 995 (16.9% publications and Japan with 555 (9.4% publications. The top 3 most published institutes were National University of Singapore, Peking University in China, and University of Groningen in Netherlands. Nitric Oxide Biology and Chemistry was the most exploited journal for H2SBM publications with 461 articles, followed by FASEB Journal with 200 publications and Antioxidants Redox Signaling with 116 publications. The most highly cited publications and researchers in H2SBM research were also unmasked from this bibliometric analysis. Collectively, H2SBM publications exhibit a continuous trend of increase, reflecting the increased H2SBM research intensity and diversity globally.

  10. Electrochemical Quantification of Extracellular Local H2O2Kinetics Originating from Single Cells.

    Science.gov (United States)

    Bozem, Monika; Knapp, Phillip; Mirčeski, Valentin; Slowik, Ewa J; Bogeski, Ivan; Kappl, Reinhard; Heinemann, Christian; Hoth, Markus

    2017-05-15

    H 2 O 2 is produced by all eukaryotic cells under physiological and pathological conditions. Due to its enormous relevance for cell signaling at low concentrations and antipathogenic function at high concentrations, precise quantification of extracellular local H 2 O 2 concentrations ([H 2 O 2 ]) originating from single cells is required. Using a scanning electrochemical microscope and bare platinum disk ultramicroelectrodes, we established sensitive long-term measurements of extracellular [H 2 O 2 ] kinetics originating from single primary human monocytes (MCs) ex vivo. For the electrochemical techniques square wave voltammetry, cyclic and linear scan voltammetry, and chronoamperometry, detection limits for [H 2 O 2 ] were determined to be 5, 50, and 500 nM, respectively. Following phorbol ester stimulation, local [H 2 O 2 ] 5-8 μm above a single MC increased by 3.4 nM/s within the first 10 min before reaching a plateau. After extracellular addition of H 2 O 2 to an unstimulated MC, the local [H 2 O 2 ] decreased on average by 4.2 nM/s due to degradation processes of the cell. Using the scanning mode of the setup, we found that H 2 O 2 is evenly distributed around the producing cell and can still be detected up to 30 μm away from the cell. The electrochemical single-cell measurements were validated in MC populations using electron spin resonance spectroscopy and the Amplex ® UltraRed assay. Innovation and Conclusion: We demonstrate a highly sensitive, spatially, and temporally resolved electrochemical approach to monitor dynamics of production and degradation processes for H 2 O 2 separately. Local extracellular [H 2 O 2 ] kinetics originating from single cells is quantified in real time. Antioxid. Redox Signal. 00, 000-000.

  11. Optimized oral cholera vaccine distribution strategies to minimize disease incidence: A mixed integer programming model and analysis of a Bangladesh scenario.

    Science.gov (United States)

    Smalley, Hannah K; Keskinocak, Pinar; Swann, Julie; Hinman, Alan

    2015-11-17

    In addition to improved sanitation, hygiene, and better access to safe water, oral cholera vaccines can help to control the spread of cholera in the short term. However, there is currently no systematic method for determining the best allocation of oral cholera vaccines to minimize disease incidence in a population where the disease is endemic and resources are limited. We present a mathematical model for optimally allocating vaccines in a region under varying levels of demographic and incidence data availability. The model addresses the questions of where, when, and how many doses of vaccines to send. Considering vaccine efficacies (which may vary based on age and the number of years since vaccination), we analyze distribution strategies which allocate vaccines over multiple years. Results indicate that, given appropriate surveillance data, targeting age groups and regions with the highest disease incidence should be the first priority, followed by other groups primarily in order of disease incidence, as this approach is the most life-saving and cost-effective. A lack of detailed incidence data results in distribution strategies which are not cost-effective and can lead to thousands more deaths from the disease. The mathematical model allows for what-if analysis for various vaccine distribution strategies by providing the ability to easily vary parameters such as numbers and sizes of regions and age groups, risk levels, vaccine price, vaccine efficacy, production capacity and budget. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. 77 FR 28764 - Temporary Non-agricultural Employment of H-2B Aliens in the United States

    Science.gov (United States)

    2012-05-16

    ... H-2B Aliens in the United States AGENCY: Employment and Training Administration, Labor. ] ACTION... Aliens in the United States, published February 21, 2012 (the 2012 H-2B Final Rule). The 2012 H-2B Final...

  13. Ab initio studies of O-2(-) (H2O)(n) and O-3(-) (H2O)(n) anionic molecular clusters, n

    DEFF Research Database (Denmark)

    Bork, Nicolai Christian; Kurten, T.; Enghoff, Martin Andreas Bødker

    2011-01-01

    An ab initio study of gaseous clusters of O-2(-) and O-3(-) with water is presented. Based on thorough scans of configurational space, we determine the thermodynamics of cluster growth. The results are in good agreement with benchmark computational methods and existing experimental data. We find...... that anionic O-2(-)(H2O)n and O-3(-)(H2O)n clusters are thermally stabilized at typical atmospheric conditions for at least n = 5. The first 4 water molecules are strongly bound to the anion due to delocalization of the excess charge while stabilization of more than 4 H2O is due to normal hydrogen bonding...... finally, the thermodynamics of a few relevant cluster reactions are considered....

  14. New ab initio potential energy surface for BrH2 and rate constants for the H + HBr → H2 + Br abstraction reaction.

    Science.gov (United States)

    Jiang, Bin; Xie, Changjian; Xie, Daiqian

    2011-03-21

    A global potential energy surface (PES) for the electronic ground state of the BrH(2) system was constructed based on the multireference configuration interaction (MRCI) method including the Davidson's correction using a large basis set. In addition, the spin-orbit correction were computed using the Breit-Pauli Hamiltonian and the unperturbed MRCI wavefunctions in the Br + H(2) channel and the transition state region. Adding the correction to the ground state potential, the lowest spin-orbit correlated adiabatic potential was obtained. The characters of the new potential are discussed. Accurate initial state specified rate constants for the H + HBr → H(2) + Br abstraction reaction were calculated using a time-dependent wave packet method. The predicted rate constants were found to be in excellent agreement with the available experimental values and much better than those obtained from a previous PES.

  15. The stable isotopic signature of biologically produced molecular hydrogen (H2

    Directory of Open Access Journals (Sweden)

    T. Röckmann

    2012-10-01

    Full Text Available Biologically produced molecular hydrogen (H2 is characterised by a very strong depletion in deuterium. Although the biological source to the atmosphere is small compared to photochemical or combustion sources, it makes an important contribution to the global isotope budget of H2. Large uncertainties exist in the quantification of the individual production and degradation processes that contribute to the atmospheric budget, and isotope measurements are a tool to distinguish the contributions from the different sources. Measurements of δ D from the various H2 sources are scarce and for biologically produced H2 only very few measurements exist. Here the first systematic study of the isotopic composition of biologically produced H2 is presented. In a first set of experiments, we investigated δ D of H2 produced in a biogas plant, covering different treatments of biogas production. In a second set of experiments, we investigated pure cultures of several H2 producing microorganisms such as bacteria or green algae. A Keeling plot analysis provides a robust overall source signature of δ D = −712‰ (±13‰ for the samples from the biogas reactor (at 38 °C, δ DH2O= +73.4‰, with a fractionation constant ϵH2-H2O of −689‰ (±20‰ between H2 and the water. The five experiments using pure culture samples from different microorganisms give a mean source signature of δ D = −728‰ (±28‰, and a fractionation constant ϵH2-H2O of −711‰ (±34‰ between H2 and the water. The results confirm the massive deuterium depletion of biologically produced H2 as was predicted by the calculation of the thermodynamic fractionation factors for hydrogen exchange between H2 and water vapour. Systematic errors in the isotope scale are difficult to assess in the absence of international standards for δ D of H2. As expected for a thermodynamic equilibrium, the fractionation factor is temperature dependent, but largely independent of the

  16. Observation of mixed acetylene - Nitrous oxide trimers: Infrared spectra of C2H2-(N2O)2 and (C2H2)2-N2O

    Science.gov (United States)

    Sheybani-Deloui, S.; Yousefi, M.; Norooz Oliaee, J.; McKellar, A. R. W.; Moazzen-Ahmadi, N.

    2014-12-01

    Infrared spectra of the lowest energy isomers of C2H2-(N2O)2 and (C2H2)2-N2O were observed in the region of the ν1 fundamental band of the N2O monomer (∼2224 cm-1) using a tunable diode laser and/or a CW quantum cascade laser to probe a pulsed supersonic slit jet expansion. One infrared band was measured for each trimer. The band for C2H2-(N2O)2 corresponds to the out-of-phase vibrations of the pair of equivalent N2O monomers. It is blue shifted by about 10 cm-1 with respect to the free N2O monomer. The band for (C2H2)2-N2O is slightly less blue shifted (centered at 2232.81 cm-1). It can be simulated as a predominately a-type band. In addition to the normal isotopologues, the corresponding bands for C2D2-(N2O)2 and (C2D2)2-N2O were also observed. The structures of these trimers are similar to those of the lowest energy isomers of the analogous OCS - acetylene trimers reported previously, that is, a twisted barrel with C2 symmetry for C2H2-(N2O)2 and a distorted T-shaped acetylene dimer with a coplanar N2O beside the stem of the T for (C2H2)2-N2O. Here, we present our observation and experimental results, which agree well with calculations based on distributed multipole pair potentials.

  17. Quantum tunneling during interstellar surface-catalyzed formation of water: the reaction H + H2O2 → H2O + OH.

    Science.gov (United States)

    Lamberts, Thanja; Samanta, Pradipta Kumar; Köhn, Andreas; Kästner, Johannes

    2016-12-07

    The final step of the water formation network on interstellar grain surfaces starting from the H + O2 route is the reaction between H and H2O2. This reaction is known to have a high activation energy and therefore at low temperatures it can only proceed via tunneling. To date, however, no rate constants are available at temperatures below 200 K. In this work, we use instanton theory to compute rate constants for the title reaction with and without isotopic substitutions down to temperatures of 50 K. The calculations are based on density functional theory, with additional benchmarks for the activation energy using unrestricted single-reference and multireference coupled-cluster single-point energies. Gas-phase bimolecular rate constants are calculated and compared with available experimental data not only for H + H2O2 → H2O + OH, but also for H + H2O2 → H2 + HO2. We find a branching ratio where the title reaction is favored by at least two orders of magnitude at 114 K. In the interstellar medium this reaction predominantly occurs on water surfaces, which increases the probability that the two reactants meet. To mimic this, one, two, or three spectator H2O molecules are added to the system. Eley-Rideal bimolecular and Langmuir-Hinshelwood unimolecular rate constants are presented here. The kinetic isotope effects for the various cases are compared to experimental data as well as to expressions commonly used in astrochemical models. Both the rectangular barrier and the Eckart approximations lead to errors of about an order of magnitude. Finally, fits of the rate constants are provided as input for astrochemical models.

  18. Water Ice Radiolytic O2, H2, and H2O2 Yields for Any Projectile Species, Energy, or Temperature: A Model for Icy Astrophysical Bodies

    Science.gov (United States)

    Teolis, B. D.; Plainaki, C.; Cassidy, T. A.; Raut, U.

    2017-10-01

    O2, H2, and H2O2 radiolysis from water ice is pervasive on icy astrophysical bodies, but the lack of a self-consistent, quantitative model of the yields of these water products versus irradiation projectile species and energy has been an obstacle to estimating the radiolytic oxidant sources to the surfaces and exospheres of these objects. A major challenge is the wide variation of O2 radiolysis yields between laboratory experiments, ranging over 4 orders of magnitude from 5 × 10-7 to 5 × 10-3 molecules/eV for different particles and energies. We revisit decades of laboratory data to solve this long-standing puzzle, finding an inverse projectile range dependence in the O2 yields, due to preferential O2 formation from an 30 Å thick oxygenated surface layer. Highly penetrating projectile ions and electrons with ranges ≳30 Å are therefore less efficient at producing O2 than slow/heavy ions and low-energy electrons (≲ 400 eV) which deposit most energy near the surface. Unlike O2, the H2O2 yields from penetrating projectiles fall within a comparatively narrow range of (0.1-6) × 10-3 molecules/eV and do not depend on range, suggesting that H2O2 forms deep in the ice uniformly along the projectile track, e.g., by reactions of OH radicals. We develop an analytical model for O2, H2, and H2O2 yields from pure water ice for electrons and singly charged ions of any mass and energy and apply the model to estimate possible O2 source rates on several icy satellites. The yields are upper limits for icy bodies on which surface impurities may be present.

  19. Problemas de salud de los jornaleros tamaulipecos empleados con visas h-2a en Estados Unidos Health problems of tamaulipas's farm workers employed with h-2a visas in the United States

    Directory of Open Access Journals (Sweden)

    Simón Pedro Izcara Palacios

    2011-01-01

    Full Text Available Desde hace dos décadas los jornaleros tamaulipecos han recibido un considerable número de visas H-2A para trabajar en la agricultura en Estados Unidos. Los empleadores estadounidenses muestran una cierta preferencia por los jornaleros tamaulipecos, ya que la cercanía de Tamaulipas a la frontera disminuye los costos de transporte, que deben ser asumidos por los empleadores. Los programas de trabajadores huéspedes para mano de obra no cualificada exponen a los trabajadores foráneos al abuso y la explotación. La falta de cumplimiento con algunas regulaciones federales como el Estándar de Protección de los Trabajadores o el Seguro de Compensación Laboral incrementa el riesgo de envenenamiento por agroquímicos y accidentes entre los jornaleros, y aquellos que sufren accidentes laborales o enfermedades no reciben atención médica. Este artículo examina los problemas de salud sufridos por los trabajadores tamaulipecos empleados con visas H-2A en la agricultura estadounidense.From two decades ago Tamaulipas' farm workers have received a large amount of H-2A visas to work in the farming sector. U.S. farmers find it appealing to hire Tamaulipas' workers because of the proximity of Tamaulipas to the frontier, which lowers transportation costs, which have to be paid by the employers. It is well reported that low-skilled guest worker programs leaves foreign workforce open to abuse and exploitation. Poor compliance with federal regulations like the Worker Protection Standard and Workers Compensation Insurance increases the risk of pesticide poisoning and injuries among agricultural workers, and those who suffer work-related injuries or illnesses forgo needed medical care. This paper examines the health problems suffered by Tamaulipas's H-2A workers employed in U.S. agriculture.

  20. Sol-gel processed magnesium-doped silica membranes with improved H2/CO2 separation

    NARCIS (Netherlands)

    Karakiliç, Pelin; Huiskes, Cindy; Luiten-Olieman, Maria W.J.; Nijmeijer, Arian; Winnubst, A.J.A.

    2017-01-01

    Magnesium-doped silica membranes were synthesized and a large increase in H2/CO2 permselectivity is achieved as compared to undoped silica membranes. Three magnesium concentrations were studied, namely 10, 15 and 20 mol%, in order to find the optimal Mg-concentration for the highest H2/CO2

  1. H2O2-induced higher order chromatin degradation: A novel ...

    Indian Academy of Sciences (India)

    The genotoxicity of reactive oxygen species (ROS) is well established. The underlying mechanism involves oxidation of DNA by ROS. However, we have recently shown that hydrogen peroxide (H2O2), the major mediator of oxidative stress, can also cause genomic damage indirectly. Thus, H2O2 at pathologically relevant ...

  2. Degradation of acidic Orange G dye using UV-H2O2 in batch ...

    African Journals Online (AJOL)

    Degradation of Orange G dye has been investigated using UV irradiation with hydrogen peroxide (H2O2) in a batch photoreactor. UV irradiation and H2O2 resulted in significant photodegradation of the dye although the effect individual reaction was very little. The degradation was studied to elucidate the effect of various ...

  3. Transport properties of the H2O@C60-dimer-based junction.

    Science.gov (United States)

    Zhu, Chengbo; Wang, Xiaolin

    2015-09-23

    Theoretical predictions play an important role in finding potential applications in molecular electronics. Fullerenes have a number of potential applications, and the charge flow from a single C60 molecule to another becomes more versatile and more interesting after doping. Here, we report the conductance of two H2O@C60 molecules in series order and how the number of encapsulated water molecules influences the transport properties of the junction. Encapsulating an H2O molecule into one of the C60 cages increases the conductance of the dimer. Negative differential resistance is found in the dimer systems, and its peak-to-valley current ratio depends on the number of encapsulated H2O molecules. The conductance of the C60 dimer and the H2O@C60 dimer is two orders of magnitude smaller than that of the C60 monomer. Furthermore, we demonstrate that the conductance of the molecular junctions based on the H2O@C60 dimer can be tuned by moving the encapsulated H2O molecules. The conductance is H2O-position dependent. Our findings indicate that H2O@C60 can be used as a building block in C60-based molecular electronic devices and sensors.

  4. Crystal morphology of ADP (NH4H2PO4) : A qualitative approach

    NARCIS (Netherlands)

    Aguilo, M.; Woensdregt, C.F.

    1984-01-01

    The Hartman-Perdok theory enables one to establish the order of morphological importance of the ADP (NH4H2PO4) crystal faces from its crystal structure. Periodic Bond Chains (PBC's) have been obtained using the N−HN…O strong bonds between the ionic [NH4]+ and [H2PO4]- crystallization units. The

  5. Stability of globular proteins in H2O and D2O

    NARCIS (Netherlands)

    Efimova, Y. M.; Haemers, S.; Wierczinski, B.; Norde, W.; van Well, A. A.

    2007-01-01

    In several experimental techniques D2O rather then H2O is often used as a solvent for proteins. Concerning the influence of the solvent on the stability of the proteins, contradicting results have been reported in literature. In this paper the influence of H2O-D2O solvent substitution on the

  6. Stability of globular proteins in H2O and in D2O

    NARCIS (Netherlands)

    Efimova, Y.M.; Haemers, S.; Wierczinsky, B.; Norde, W.; Well, van A.A.

    2007-01-01

    In several experimental techniques D2O rather then H2O is often used as a solvent for proteins. Concerning the influence of the solvent on the stability of the proteins, contradicting results have been reported in literature. In this paper the influence of H2O-D2O solvent substitution on the

  7. Pretreatment of seed with H2O2 enhances drought tolerance of ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-11-16

    Nov 16, 2009 ... water use efficiency (WUE) and proline level. H2O2 pretreatment enhanced the membrane stability, as ... ments and cultivation techniques for wheat production. Among various technique strategies, pre-sowing ... were surface sterilized with 75% ethanol for 2 min followed by repeated washings with ddH2O.

  8. Ni foam cathode enables high volumetric H2 production in a microbial electrolysis cell

    NARCIS (Netherlands)

    Jeremiasse, A.W.; Hamelers, H.V.M.; Saakes, M.; Buisman, C.J.N.

    2010-01-01

    Valuable, “green” H2 can be produced with a microbial electrolysis cell (MEC). To achieve a high volumetric production rate of high purity H2, a continuous flow MEC with an anion exchange membrane, a flow through bioanode and a flow through Ni foam cathode was constructed. At an electrical energy

  9. Role of H2AX in DNA damage response and human cancers.

    NARCIS (Netherlands)

    Srivastava, N.; Gochhait, S.; Boer, P. de; Bamezai, R.N.

    2009-01-01

    H2AX, the evolutionarily conserved variant of histone H2A, has been identified as one of the key histones to undergo various post-translational modifications in response to DNA double-strand breaks (DSBs). By virtue of these modifications, that include acetylation, phosphorylation and

  10. Full Length Research Paper Lack of correlation between H 2O 2 ...

    African Journals Online (AJOL)

    substance, we attempted to determine if there is a consistent link between in vitro anti-staphylococcal activity and H2O2 production by Lactobacillus spp. A simple quantitative analysis of H2O2 produced by Lactobacillus spp. was performed by a modified spectrophotometric method. A statistically significant correlation was ...

  11. Image-Based Measurement of H2O2 Reaction-Diffusion in Wounded Zebrafish Larvae.

    Science.gov (United States)

    Jelcic, Mark; Enyedi, Balázs; Xavier, João B; Niethammer, Philipp

    2017-05-09

    Epithelial injury induces rapid recruitment of antimicrobial leukocytes to the wound site. In zebrafish larvae, activation of the epithelial NADPH oxidase Duox at the wound margin is required early during this response. Before injury, leukocytes are near the vascular region, that is, ∼100-300 μm away from the injury site. How Duox establishes long-range signaling to leukocytes is unclear. We conceived that extracellular hydrogen peroxide (H2O2) generated by Duox diffuses through the tissue to directly regulate chemotactic signaling in these cells. But before it can oxidize cellular proteins, H2O2 must get past the antioxidant barriers that protect the cellular proteome. To test whether, or on which length scales this occurs during physiological wound signaling, we developed a computational method based on reaction-diffusion principles that infers H2O2 degradation rates from intravital H2O2-biosensor imaging data. Our results indicate that at high tissue H2O2 levels the peroxiredoxin-thioredoxin antioxidant chain becomes overwhelmed, and H2O2 degradation stalls or ceases. Although the wound H2O2 gradient reaches deep into the tissue, it likely overcomes antioxidant barriers only within ∼30 μm of the wound margin. Thus, Duox-mediated long-range signaling may require other spatial relay mechanisms besides extracellular H2O2 diffusion. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  12. Characterization and optimization of cathodic conditions for H2O2 synthesis in microbial electrochemical cells

    Science.gov (United States)

    Cathode potential and O2 supply methods were investigated to improve H2O2 synthesis in an electrochemical cell, and optimal cathode conditions were applied for microbial electrochemical cells (MECs). Using aqueous O2 for the cathode significantly improved current density, but H2...

  13. 75 FR 6883 - Temporary Agricultural Employment of H-2A Aliens in the United States

    Science.gov (United States)

    2010-02-12

    ... Temporary Agricultural Employment of H-2A Aliens in the United States; Final Rule #0;#0;Federal Register... Temporary Agricultural Employment of H-2A Aliens in the United States AGENCY: Employment and Training... services involved in the petition; and (B) The employment of the alien in such labor or services will not...

  14. The transcriptional regulator c2h2 acceleratesmushroom formation in Agaricus bisporus

    NARCIS (Netherlands)

    Pelkmans, Jordi F.; Vos, A.M.; Scholtmeijer, Karin; Hendrix, Ed; Baars, Johan J.P.; Gehrmann, T.; Reinders, M.J.T.; Lugones, Luis G.; Wösten, Han A.B.

    2016-01-01

    The Cys2His2 zinc finger protein gene c2h2 of Schizophyllum commune is involved in mushroom formation. Its inactivation results in a strain that is arrested at the stage of aggregate formation. In this study, the c2h2 orthologue of Agaricus bisporus was over-expressed in this white button mushroom

  15. The transcriptional regulator c2h2 accelerates mushroom formation in Agaricus bisporus

    NARCIS (Netherlands)

    Pelkmans, J.F.; Vos, A.M.; Scholtmeijer, K; Hendrix, Eddy; Baars, Johan J; Gehrmann, Thies; Reinders, Marcel J; Lugones, L.G.; Wösten, HAB

    The Cys2His2 zinc finger protein gene c2h2 of Schizophyllum commune is involved in mushroom formation. Its inactivation results in a strain that is arrested at the stage of aggregate formation. In this study, the c2h2 orthologue of Agaricus bisporus was over-expressed in this white button mushroom

  16. The transcriptional regulator c2h2 accelerates mushroom formation in Agaricus bisporus

    NARCIS (Netherlands)

    Pelkmans, Jordi F.; Vos, Aurin M.; Scholtmeijer, Karin; Hendrix, Ed; Baars, Johan J.P.; Gehrmann, Thies; Reinders, Marcel J.T.; Lugones, Luis G.; Wösten, Han A.B.

    2016-01-01

    The Cys2His2 zinc finger protein gene c2h2 of Schizophyllum commune is involved in mushroom formation. Its inactivation results in a strain that is arrested at the stage of aggregate formation. In this study, the c2h2 orthologue of Agaricus bisporus was over-expressed in this white button

  17. Anti-inflammatory effects of H2S during acute bacterial infection: a review

    National Research Council Canada - National Science Library

    Francesca Benedetti; Sabrina Curreli; Selvi Krishnan; Sergio Davinelli; Fiorenza Cocchi; Giovanni Scapagnini; Robert C Gallo; Davide Zella

    2017-01-01

    .... The precise role of H2S in inflammation is still largely unknown. In particular, the role of H2S in the regulation of the inflammatory response in acute and chronic infections is being actively investigated because of its potential therapeutic use...

  18. ORFEUS II echelle spectra : Absorption by H-2 in the LMC

    NARCIS (Netherlands)

    de Boer, KS; Richter, P; Bomans, DJ; Heithausen, A; Koornneef, J

    1998-01-01

    We report the first detection of H-2 absorption profiles of LMC gas on the line of sight to star 3120 in the association LH 10 near the emission nebula N 11B. Transitions found in the Lyman band are used to derive a total column density N(H-2) = 6.6 x 10(18) cm(-2). Excitation temperatures of less

  19. Interaction of H2 with stoichiometric and O-rich RuO2 (110) surfaces

    Science.gov (United States)

    Wei, Yinying; Martinez, Umberto; Lammich, Lutz; Besenbacher, Flemming; Wendt, Stefan

    2014-03-01

    In this talk, I will present combined high-resolution STM, TPD, and DFT studies on the interaction of H2 with stoichiometric and O-rich RuO2(110) surfaces. On stoichiometric RuO2(110), H2 adsorbs molecularly on-top on Rucus sites for temperatures lower than 90 K. At higher temperatures such as 150 K, H2 molecules adsorb dissociatively on stoichiometric RuO2(110), leading to pairs of H species with one H adsorbed on-top on a Rucus site and the second at an adjacent Obr atom. On O-rich RuO2(110) surfaces characterized by O on-top species, H2 exposure followed by ramping the sample temperature leads to H2O formation. Systematic TPD measurements showed that the largest quantity of H2O forms at low adsorption temperatures and at a medium O on-top coverage. Our STM studies revealed different intermediate species depending on the H2 adsorption temperature. Based on these results it is proposed that the H2 sticking coefficient and the diffusivity of H adatoms play important roles in the hydrogen adsorption and the subsequent water formation reactions. We acknowledge the support of Danish Research Agency, the Strategic Research Council, and the European Research Council through an Advanced ERC grant (F.B.).

  20. Adsorption of H2O and CO2 on supported amine sorbents

    NARCIS (Netherlands)

    Veneman, Rens; Frigka, Natalia; Zhao, Wenying; Li, Zhenshan; Kersten, Sascha R.A.; Brilman, Derk Willem Frederik

    2015-01-01

    In this work the adsorption of H2O and CO2 on Lewatit VP OC 1065 was studied in view of the potential application of this sorbent in post combustion CO2 capture. Both CO2 and H2O were found to adsorb on the amine active sites present on the pore surface of the sorbent material. However, where the

  1. Synthesis of H2SO4 doped polyaniline film by potentiometric method

    Indian Academy of Sciences (India)

    H2SO4 doped polyaniline films were synthesized in aqueous acidic media. The polyaniline film deposited on platinum electrode exhibits highest conductivity. The conductivity of each H2SO4 doped polyaniline sample was determined by the four-probe technique. The current–voltage curve exhibits that polyaniline sample ...

  2. Characteristics of H2S emission from aged refuse after excavation exposure.

    Science.gov (United States)

    Shen, Dong-Sheng; Du, Yao; Fang, Yuan; Hu, Li-Fang; Fang, Cheng-Ran; Long, Yu-Yang

    2015-05-01

    Hydrogen sulfide (H2S(g)) emission from landfills is a widespread problem, especially when aged refuse is excavated. H2S(g) emission from aged refuse exposed to air was investigated and the results showed that large amounts of H2S(g) can be released, especially in the first few hours after excavation, when H2S(g) concentrations in air near refuse could reach 2.00 mg m(-3). Initial exposure to air did not inhibit the emission of H2S(g), as is generally assumed, but actually promoted it. The amounts of H2S(g) emitted in the first 2 d after excavation can be very dangerous, and the risks associated with the emission of H2S(g) could decrease significantly with time. Unlike a large number of sulfide existed under anaerobic conditions, the sulfide in aged municipal solid waste can be oxidized chemically to elemental sulfur (but not sulfate) under aerobic conditions, and its conversion rate was higher than 80%. Only microorganisms can oxidize the reduced sulfur species to sulfate, and the conversion rate could reach about 50%. Using appropriate techniques to enhance these chemical and biological transformations could allow the potential health risks caused by H2S(g) after refuse excavation to be largely avoided. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. [H 2 -Cryptand 222] 2+ (Br 3 – ) 2 as a Tribromide-Type Catalyst for ...

    African Journals Online (AJOL)

    A stable organic tribromide, [H2-cryptand 222]2+(Br3–)2 was utilized as an active catalyst for the trimethylsilylation/tetrahydropyranylation of alcohols. The method is general for the preparation of OH-protected aliphatic (acyclic and cyclic), aromatic, primary, secondary and tertiary alcohols. Keywords: [H2-cryptand ...

  4. FREEZING TOLERANCE AND BIOCHEMICAL-CHANGES IN WHEAT SHOOTS AS AFFECTED BY H2S FUMIGATION

    NARCIS (Netherlands)

    Stuiver, C.E.E.; De Kok, Luit J.; Kuiper, P.J.C.

    1992-01-01

    Fumigation of winter wheat with H2S during low temperature acclimation substantially reduced the development of freezing tolerance of the leaves. After 6 weeks of low temperature exposure (3-degrees-C), the freezing tolerance was increased by 6 and 2-degrees-C at 0 and 0.25-mu-l l-1 H2S,

  5. Biotechnological removal of H2S and thiols from sour gas streams under haloalkaline conditions

    NARCIS (Netherlands)

    Roman, P.

    2016-01-01

    Biotechnological removal of H2S and thiols from sour gas streams under haloalkaline conditions Paweł Roman Abstract Biological removal of H2S from sour gas streams became popular in recent years because of high process efficiency and low operational costs. To expand

  6. The rotational excitation of the interstellar HNC by para- and ortho-H2.

    Science.gov (United States)

    Dumouchel, Fabien; Kłos, Jacek; Lique, François

    2011-05-14

    Rotational excitation of the interstellar HNC due to collisions with H(2) is investigated. We present a new four dimensional (4D) potential energy surface for the HNC-H(2) collisional system. Both molecules were treated as rigid rotors. Interaction energy was obtained from the electronic structure calculations using a single and double-excitation coupled cluster method with perturbative contributions from connected triple excitations [CCSD(T)]. The five atoms were described using the aug-cc-pVTZ basis sets. Bond functions were placed at mid-distance between the HNC center of mass and the center of mass of H(2) for a better description of the van der Waals interaction. Close coupling calculations of the inelastic integral cross sections of HNC in collisions with para-H(2) and ortho-H(2) were calculated for kinetic energies up to 800 cm(-1). After Boltzmann thermal averaging, rate coefficients were obtained for temperatures ranging from 5 to 100 K. Significant differences exist between para- and ortho-H(2) results. The strongest collision-induced rotational HNC transitions are the transitions with Δj = 1 for collisions with para-H(2) and with ortho-H(2). The new rate coefficients should induce important consequences on the determination of HNC abundance in the interstellar medium. In particular, we expect that they will help to solve the interstellar problem of relative abundance of the HCN and HNC isomers.

  7. Suitability of the H2S test for detection of fecal contamination in ...

    African Journals Online (AJOL)

    The suitability of H2S field test to detect fecal contamination in drinking water was assessed by analysing 635 water samples from various sources at room temperature and at 37°C after 18, 24, and 48 h of incubation. The H2S test showed 216, 85, 96 and 85% correlation with Eijkman test, membrane filter technique, most ...

  8. Constitutive expression of gamma-H2AX has prognostic relevance in triple negative breast cancer

    NARCIS (Netherlands)

    Nagelkerke, A.P.; Kuijk, S.J. van; Sweep, F.C.; Nagtegaal, I.D.; Hoogerbrugge, N.; Martens, J.W.; Timmermans, M.A.Y.; Laarhoven, H.W.M. van; Bussink, J.; Span, P.N.

    2011-01-01

    BACKGROUND AND PURPOSE: Constitutive gamma-H2AX expression might indicate disruption of the DNA damage repair pathway, genomic instability, or shortened telomeric ends. Here, we quantified expression of endogenous gamma-H2AX and its downstream factor 53BP1 in a large number of breast cancer cell

  9. 26 CFR 1.430(h)(2)-1 - Interest rates used to determine present value.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 5 2010-04-01 2010-04-01 false Interest rates used to determine present value... to the interest rates to be applied for a plan year under section 430(h)(2). Section 430(h)(2) and... defined in section 414(f)). Paragraph (b) of this section describes how the segment interest rates are...

  10. Effects of hydrogen sulfide (H2S) on respiration control of state 3/4 in ...

    African Journals Online (AJOL)

    hope&shola

    2012-03-13

    Mar 13, 2012 ... Hydrogen sulfide (H2S) could availably regulate electron transport in the inner membrane of mitochondria from bovine heart when succinate as substrate and rotenone as complex I inhibitor at. 37°C were used. H2S increased to a certain extent the respiratory rate of state 4. It also increased first and then ...

  11. Characterization and optimization of cathodic conditions for H2O2 synthesis in microbial electrochemical cells.

    Science.gov (United States)

    Sim, Junyoung; An, Junyeong; Elbeshbishy, Elsayed; Ryu, Hodon; Lee, Hyung-Sool

    2015-11-01

    Cathode potential and O2 supply methods were investigated to improve H2O2 synthesis in an electrochemical cell, and optimal cathode conditions were applied for microbial electrochemical cells (MECs). Using aqueous O2 for the cathode significantly improved current density, but H2O2 conversion efficiency was negligible at 0.3-12%. Current density decreased for passive O2 diffusion to the cathode, but H2O2 conversion efficiency increased by 65%. An MEC equipped with a gas diffusion cathode was operated with acetate medium and domestic wastewater, which presented relatively high H2O2 conversion efficiency from 36% to 47%, although cathode overpotential was fluctuated. Due to different current densities, the maximum H2O2 production rate was 141 mg H2O2/L-h in the MEC fed with acetate medium, but it became low at 6 mg H2O2/L-h in the MEC fed with the wastewater. Our study clearly indicates that improving anodic current density and mitigating membrane fouling would be key parameters for large-scale H2O2-MECs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Effects of hydrogen sulfide (H 2 S) on respiration control of state 3/4 ...

    African Journals Online (AJOL)

    Experimental results indicated that more than 10 µM H2S brought about uncoupling of mitochondrial electron transport and the opening of mitochondrial KATP channel located in complex III-IV, and less than 10 µM H2S unexpectedly facilitated this course, which might be via sulfide-quinone oxidoreductase. The finding that ...

  13. System and method to control h2o2 level in advanced oxidation processes

    DEFF Research Database (Denmark)

    2016-01-01

    The present invention relates to a bio-electrochemical system (BES) and a method of in-situ production and removal of H2O2 using such a bio-electrochemical system (BES). Further, the invention relates to a method for in-situ control of H2O2 content in an aqueous system of advanced oxidation...

  14. Activity and Selectivity for O-2 Reduction to H2O2 on Transition Metal Surfaces

    DEFF Research Database (Denmark)

    Siahrostami, Samira; Verdaguer Casadevall, Arnau; Karamad, Mohammadreza

    2013-01-01

    Industrially viable electrochemical production of H2O2 requires active, selective and stable electrocatalyst materials to catalyse the oxygen reduction reaction to H2O2. On the basis of density functional theory calculations, we explain why single site catalysts such as Pd/Au show improved...

  15. The synthesis and hydrogen storage properties of a MgH(2) incorporated carbon aerogel scaffold.

    Science.gov (United States)

    Zhang, Shu; Gross, Adam F; Van Atta, Sky L; Lopez, Maribel; Liu, Ping; Ahn, Channing C; Vajo, John J; Jensen, Craig M

    2009-05-20

    A new approach to the incorporation of MgH2 in the nanometer-sized pores of a carbon aerogel scaffold was developed, by infiltrating the aerogel with a solution of dibutylmagnesium (MgBu2) precursor, and then hydrogenating the incorporated MgBu2 to MgH2. The resulting impregnated material showed broad x-ray diffraction peaks of MgH2. The incorporated MgH2 was not visible using a transmission electron microscope, which indicated that the incorporated hydride was nanosized and confined in the nanoporous structure of the aerogel. The loading of MgH2 was determined as 15-17 wt%, of which 75% is reversible over ten cycles. Incorporated MgH2 had >5 times faster dehydrogenation kinetics than ball-milled activated MgH2, which may be attributed to the particle size of the former being smaller than that of the latter. Cycling tests of the incorporated MgH(2) showed that the dehydrogenation kinetics are unchanged over four cycles. Our results demonstrate that confinement of metal hydride materials in a nanoporous scaffold is an efficient way to avoid aggregation and improve cycling kinetics for hydrogen storage materials.

  16. Impact of a future H2 transportation on atmospheric pollution in Europe

    NARCIS (Netherlands)

    Popa, M. E.|info:eu-repo/dai/nl/375806407; Segers, A. J.; Denier van der Gon, H. A C; Krol, M. C.|info:eu-repo/dai/nl/078760410; Visschedijk, A. J H; Schaap, M.|info:eu-repo/dai/nl/413333175; Röckmann, T.|info:eu-repo/dai/nl/304838233

    2015-01-01

    Hydrogen (H2) is being explored as a fuel for passenger vehicles; it can be used in fuel cells to power electric motors or burned in internal combustion engines. In order to evaluate the potential influence of a future H2-based road transportation on the regional air quality in Europe, we

  17. Dispersion capacitive de l'interface H 2 SO 4 /Pt | Hammadi ...

    African Journals Online (AJOL)

    Capacitive dispersion of Pt/H2SO4 interface. Impedance measurements by EIS and voltammograms measurements by CV on pretreated Pt electrodes immersed in an electrolytic solution of 0.5M H2SO4 are presented. Two electrochemical pretreatment techniques of the WE (thin Pt wire) are used: cleaning and etching.

  18. Adsorption of CO2 and H2O on supported amine sorbents

    NARCIS (Netherlands)

    Veneman, Rens; Zhao, W.; Li, Z.; Cai, N.; Brilman, Derk Willem Frederik

    2014-01-01

    In this work we have evaluated the H2O and CO2 adsorption characteristics of Lewatit VP OC 1065 in view of the potential application of solid sorbents in post combustion CO2 capture. Here we present single component adsorption isotherms for H2O and CO2 as well as co-adsorption experiments. It was

  19. UTILIZATION OF ATMOSPHERIC H2S BY PLANT FOLIAR TISSUE : ITS INTERACTION WITH SULFATE ASSIMILATION

    NARCIS (Netherlands)

    Poortinga, A.M.; de Kok, L.J.

    Exposure of spinach cotyledons to H2S or sulfate resulted in a concentration and time dependent accumulation of water-soluble non-protein thiols. The increase in thiol content upon a combined exposure to H2S and sulfate was comparable to that of the sum of the increases obtained by the individual

  20. Conductivity of Composite Material Based on System NdPO4·nH2OCsH2PO4

    DEFF Research Database (Denmark)

    Anfimova, Tatiana; Bjerrum, Niels J.; Li, Qingfeng

    2013-01-01

    The goal of the present study was to obtain a comprehensive knowledge about synthesis conditions, structure, thermal behavior and conductivity properties of neodymiumorthophosphates in order to analyze of use this material in intermediate temperature fuel cells due to their thermal and chemical...... stability properties.The impedance spectroscopy technique (IS) was used to measure the conductivity. The conductivity of composites observed to be lower than conductivity of pure CsH2PO4 but had improved sufficiently conductivity of pure NdPO4·nH2O...

  1. Decapado de un acero inoxidable austenítico mediante mezclas ecológicas basadas en H2O2 - H2SO4 - iones F-

    Directory of Open Access Journals (Sweden)

    Narváez, L.

    2013-04-01

    Full Text Available This study reports the pickling of 316L stainless steel using mixtures of hydrogen peroxide (H2O2, sulphuric acid (H2SO4 and fluoride ions as hydrofluoric acid (HF, sodium fluoride (NaF and potassium fluoride (KF. The decomposition of H2O2 in the mixtures was assessed at different temperatures 25 °C to 60 °C, with ferric ion contents from 0 to 40 g/l. According to the results obtained, were established the optimal condition pickling at 20 g/l of ferric ions, 25 °C and p-toluensulphonic acid as stabilizer of H2O2. The HF pickling mixture was the only capable to remove totally the oxide layer from the 316L stainless steel after 300 s. The fluoride salts pickling mixtures only remove partially the oxide layer (20 to 40 % aprox. after 300 s. When the pickling time was increased until 1200 s, the removal percentages were around to 80 %.En este estudio se presenta el decapado del acero inoxidable austenítico 316L utilizando mezclas de peróxido de hidrógeno (H2O2/ácido sulfúrico (H2SO4/iones fluoruro; los iones fluoruro provienen del ácido fluorhídrico (HF, fluoruro de sodio (NaF y fluoruro de potasio (KF. La estabilidad del H2O2 fue valorada modificando las concentraciones del ión férrico de 0 a 40 g/l y las temperaturas de 25 °C a 60 °C en las mezclas decapantes. Se establecieron las condiciones óptimas de decapado utilizando 20 g/l de iones férrico a 25 °C empleando el ácido p-toluensulfónico como estabilizante del H2O2. La mezcla que contenía HF fue la única capaz de eliminar completamente los óxidos superficiales del acero a tiempos de 300 s. Las mezclas a base de sales fluoradas eliminaron parcialmente los óxidos (20 y 40 % aprox. en 300 s. Al incrementar el tiempo de decapado hasta 1200 s se obtuvieron porcentajes de eliminación alrededor de un 80 %.

  2. Molecular hydrogen (H2 emissions and their isotopic signatures (H/D from a motor vehicle: implications on atmospheric H2

    Directory of Open Access Journals (Sweden)

    T. Röckmann

    2010-06-01

    Full Text Available Molecular hydrogen (H2, its isotopic signature (deuterium/hydrogen, δD, carbon monoxide (CO, and other compounds were studied in the exhaust of a passenger car engine fuelled with gasoline or methane and run under variable air-fuel ratios and operating modes. H2 and CO concentrations were largely reduced downstream of the three-way catalytic converter (TWC compared to levels upstream, and showed a strong dependence on the air-fuel ratio (expressed as lambda, λ. The isotopic composition of H2 ranged from δD = −140‰ to δD = −195‰ upstream of the TWC but these values decreased to −270‰ to −370‰ after passing through the TWC. Post-TWC δD values for the fuel-rich range showed a strong dependence on TWC temperature with more negative δD for lower temperatures. These effects are attributed to a rapid temperature-dependent H-D isotope equilibration between H2 and water (H2O. In addition, post TWC δD in H2 showed a strong dependence on the fraction of removed H2, suggesting isotopic enrichment during catalytic removal of H2 with enrichment factors (ε ranging from −39.8‰ to −15.5‰ depending on the operating mode. Our results imply that there may be considerable variability in real-world δD emissions from vehicle exhaust, which may mainly depend on TWC technology and exhaust temperature regime. This variability is suggestive of a δD from traffic that varies over time, by season, and by geographical location. An earlier-derived integrated pure (end-member δD from anthropogenic activities of −270‰ (Rahn et al., 2002 can be explained as a mixture of mainly vehicle emissions from cold starts and fully functional TWCs, but enhanced δD values by >50‰ are likely for regions where TWC technology is not fully implemented. Our results also suggest that a full hydrogen isotope analysis on fuel and exhaust gas may greatly aid at understanding process-level reactions in the exhaust gas, in particular in the TWC.

  3. Electrochemical Generation of Individual O2 Nanobubbles via H2O2 Oxidation.

    Science.gov (United States)

    Ren, Hang; German, Sean R; Edwards, Martin A; Chen, Qianjin; White, Henry S

    2017-06-01

    Herein, we use Pt nanodisk electrodes (apparent radii from 4 to 80 nm) to investigate the nucleation of individual O2 nanobubbles generated by electrooxidation of hydrogen peroxide (H2O2). A single bubble reproducibly nucleates when the dissolved O2 concentration reaches ∼0.17 M at the Pt electrode surface. This nucleation concentration is ∼130 times higher than the equilibrium saturation concentration of O2 and is independent of electrode size. Moreover, in acidic H2O2 solutions (1 M HClO4), in addition to producing an O2 nanobubble through H2O2 oxidation at positive potentials, individual H2 nanobubbles can also be generated at negative potentials. Alternating generation of single O2 and H2 bubbles within the same experiment allows direct comparison of the critical concentrations for nucleation of each nanobubble without knowing the precise size/geometry of the electrode or the exact viscosity/temperature of the solution.

  4. H2FIRST: A partnership to advance hydrogen fueling station technology driving an optimal consumer experience.

    Energy Technology Data Exchange (ETDEWEB)

    Moen, Christopher D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Dedrick, Daniel E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Pratt, Joseph William [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Balfour, Bruce [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Noma, Edwin Yoichi [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Somerday, Brian P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); San Marchi, Christopher W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wipke, Keith [National Renewable Energy Lab. (NREL), Golden, CO (United States); Kurtz, Jennifer [National Renewable Energy Lab. (NREL), Golden, CO (United States); Terlip, Danny [National Renewable Energy Lab. (NREL), Golden, CO (United States); Harrison, Kevin [National Renewable Energy Lab. (NREL), Golden, CO (United States); Sprik, Samuel [National Renewable Energy Lab. (NREL), Golden, CO (United States); Harris, Aaron [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-03-01

    The US Department of Energy (DOE) Energy Efficiency and Renewable Energy (EERE) Office of Fuel Cell Technologies Office (FCTO) is establishing the Hydrogen Fueling Infrastructure Research and Station Technology (H2FIRST) partnership, led by the National Renewable Energy Laboratory (NREL) and Sandia National Laboratories (SNL). FCTO is establishing this partnership and the associated capabilities in support of H2USA, the public/private partnership launched in 2013. The H2FIRST partnership provides the research and technology acceleration support to enable the widespread deployment of hydrogen infrastructure for the robust fueling of light-duty fuel cell electric vehicles (FCEV). H2FIRST will focus on improving private-sector economics, safety, availability and reliability, and consumer confidence for hydrogen fueling. This whitepaper outlines the goals, scope, activities associated with the H2FIRST partnership.

  5. Interaction of H2S with Calcium Permeable Channels and Transporters

    Directory of Open Access Journals (Sweden)

    Weihua Zhang

    2015-01-01

    Full Text Available A growing amount of evidence has suggested that hydrogen sulfide (H2S, as a gasotransmitter, is involved in intensive physiological and pathological processes. More and more research groups have found that H2S mediates diverse cellular biological functions related to regulating intracellular calcium concentration. These groups have demonstrated the reciprocal interaction between H2S and calcium ion channels and transporters, such as L-type calcium channels (LTCC, T-type calcium channels (TTCC, sodium/calcium exchangers (NCX, transient receptor potential (TRP channels, β-adrenergic receptors, and N-methyl-D-aspartate receptors (NMDAR in different cells. However, the understanding of the molecular targets and mechanisms is incomplete. Recently, some research groups demonstrated that H2S modulates the activity of calcium ion channels through protein S-sulfhydration and polysulfide reactions. In this review, we elucidate that H2S controls intracellular calcium homeostasis and the underlying mechanisms.

  6. Investigation of the deterioration of passive films in H2S-containing solutions

    Science.gov (United States)

    Wang, Zhu; Zhang, Lei; Tang, Xian; Cui, Zhao-yang; Xue, Jun-peng; Lu, Min-xu

    2017-08-01

    The effect of H2S on the corrosion behavior of 316L stainless steel was investigated using electrochemical methods by changing the gas condition from CO2 to H2S and then back to CO2. The presence of H2S showed an acceleration effect on the corrosion of 316L stainless steel in comparison with CO2. The acceleration effect remained even after the complete removal of H2S by CO2, indicating that the passive film was irreversibly damaged. X-ray photoelectron spectroscopy (XPS) analysis indicated that the passive film was composed of Cr2O3, Fe2O3, and FeS2 after being immersed in H2S-containing solutions. The semiconducting property of the passive film was then investigated by using the Mott-Schottky approach. The presence of sulfides resulted in higher acceptor and donor densities and thus was responsible for the deterioration of passive films.

  7. Gas-Phase Photochemical Overall H2S Splitting by UV Light Irradiation.

    Science.gov (United States)

    Baldovi, Herme G; Albero, Josep; Ferrer, Belen; Mateo, Diego; Alvaro, Mercedes; García, Hermenegildo

    2017-05-09

    Splitting of hydrogen sulfide is achieved to produce value-added chemicals. Upon irradiation at 254 nm in the gas phase and in the absence of catalysts or photocatalysts at near room temperature, H 2 S splits into stoichiometric amounts of H 2 and S with a quantum efficiency close to 50 %. No influence of the presence of CH 4 and CO 2 (typical components in natural gas and biogas in which H 2 S is an unwanted component) on the efficiency of overall H 2 S splitting was observed. A mechanism for the H 2 and S formation is proposed. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Glutamine methylation in histone H2A is an RNA-polymerase-I-dedicated modification

    DEFF Research Database (Denmark)

    Tessarz, Peter; Santos-Rosa, Helena; Robson, Sam C

    2014-01-01

    Nucleosomes are decorated with numerous post-translational modifications capable of influencing many DNA processes. Here we describe a new class of histone modification, methylation of glutamine, occurring on yeast histone H2A at position 105 (Q105) and human H2A at Q104. We identify Nop1...... as the methyltransferase in yeast and demonstrate that fibrillarin is the orthologue enzyme in human cells. Glutamine methylation of H2A is restricted to the nucleolus. Global analysis in yeast, using an H2AQ105me-specific antibody, shows that this modification is exclusively enriched over the 35S ribosomal DNA...... and increased transcription at the ribosomal DNA locus. These features are phenocopied by mutations in FACT complex components. Together these data identify glutamine methylation of H2A as the first histone epigenetic mark dedicated to a specific RNA polymerase and define its function as a regulator of FACT...

  9. A Nose for Hydrogen Gas: Fast, Sensitive H2Sensors Using Electrodeposited Nanomaterials.

    Science.gov (United States)

    Penner, Reginald M

    2017-08-15

    Hydrogen gas (H 2 ) is odorless and flammable at concentrations above 4% (v/v) in air. Sensors capable of detecting it rapidly at lower concentrations are needed to "sniff" for leaked H 2 wherever it is used. Electrical H 2 sensors are attractive because of their simplicity and low cost: Such sensors consist of a metal (usually palladium, Pd) resistor. Exposure to H 2 causes a resistance increase, as Pd metal is converted into more resistive palladium hydride (PdH x ). Sensors based upon Pd alloy films, developed in the early 1990s, were both too slow and too insensitive to meet the requirements of H 2 safety sensing. In this Account, we describe the development of H 2 sensors that are based upon electrodeposited nanomaterials. This story begins with the rise to prominence of nanowire-based sensors in 2001 and our demonstration that year of the first nanowire-based H 2 sensor. The Pd nanowires used in these experiments were prepared by electrodepositing Pd at linear step-edge defects on a graphite electrode surface. In 2005, lithographically patterned nanowire electrodeposition (LPNE) provided the capability to pattern single Pd nanowires on dielectrics using electrodeposition. LPNE also provided control over the nanowire thickness (±1 nm) and width (±10-15%). Using single Pd nanowires, it was demonstrated in 2010 that smaller nanowires responded more rapidly to H 2 exposure. Heating the nanowire using Joule self-heating (2010) also dramatically accelerated sensor response and recovery, leading to the conclusion that thermally activated H 2 chemisorption and desorption of H 2 were rate-limiting steps in sensor response to and recovery from H 2 exposure. Platinum (Pt) nanowires, studied in 2012, showed an inverted resistance response to H 2 exposure, that is, the resistance of Pt nanowires decreased instead of increased upon H 2 exposure. H 2 dissociatively chemisorbs at a Pt surface to form Pt-H, but in contrast to Pd, it stays on the Pt surface. Pt nanowires

  10. Cardiac H2S Generation Is Reduced in Ageing Diabetic Mice

    Directory of Open Access Journals (Sweden)

    Sheng Jin

    2015-01-01

    Full Text Available Aims. To examine whether hydrogen sulfide (H2S generation changed in ageing diabetic mouse hearts. Results. Compared to mice that were fed tap water only, mice that were fed 30% fructose solution for 15 months exhibited typical characteristics of a severe diabetic phenotype with cardiac hypertrophy, fibrosis, and dysfunction. H2S levels in plasma, heart tissues, and urine were significantly reduced in these mice as compared to those in controls. The expression of the H2S-generating enzymes, cystathionine γ-lyase and 3-mercaptopyruvate sulfurtransferase, was significantly decreased in the hearts of fructose-fed mice, whereas cystathionine-β-synthase levels were significantly increased. Conclusion. Our results suggest that this ageing diabetic mouse model developed diabetic cardiomyopathy and that H2S levels were reduced in the diabetic heart due to alterations in three H2S-producing enzymes, which may be involved in the pathogenesis of diabetic cardiomyopathy.

  11. Failure Mechanisms of Ni-H2 and Li-Ion Batteries Under Hypervelocity Impacts

    Science.gov (United States)

    Miller, J. E.; Lyons, F.; Christiansen, E. L.; Lear, D. M.

    2017-01-01

    Lithium-Ion (Li-Ion) batteries have yielded significant performance advantages for many industries, including the aerospace industry, and have been selected to replace nickel hydrogen (Ni-H2) batteries for the International Space Station (ISS) program to meet the energy storage demands. As the ISS uses its vast solar arrays to generate its power, the solar ar-rays meet their sunlit power demands and supply excess power to battery packs for power de-livery on the sun obscured phase of the approximate 90 minute low Earth orbit. These large battery packs are located on the exterior of the ISS, and as such, the battery packs are ex-posed to external environment threats like naturally occurring meteoroids and artificial orbital debris (MMOD). While the risks from these solid particle environments has been known and addressed to an acceptable risk of failure through shield design, it is not possible to completely eliminate the risk of loss of these assets on orbit due to MMOD, and as such, failure consequences to the ISS have been considered.

  12. Performance evaluation of combined ejector LiBr/H2O absorption cooling cycle

    Directory of Open Access Journals (Sweden)

    Hasan Sh. Majdi

    2016-03-01

    Full Text Available The objective of this work is to develop a computer simulation program to evaluate the performance of solar-assited combined ejector absorption (single-effect cooling system using LiBr/H2O as a working fluid and operating under steady-state conditions. The ejector possess no moving parts and is simple and reliable, which makes it attractive for combination with single-stage absorption cycle for further improvement to the system's performance. In this research, improvement to the system is achieved by utilizing the potential kinetic energy of the ejector to enhance refrigeration efficiency. The effects of the entrainment ratio of the ejector, operating temperature, on the thermal loads, and system performance have been investigated. The results showed that the evaporator and condenser loads, post-addition of the ejector, is found to be permanently higher than that in the basic cycle, which indicates a significant enhancement of the proposed cycle and the cooling capacity of the system increasing with the increase in evaporator temperature and entrainment ratio. The COP of the modified cycle is improved by up to 60 % compared with that of the basic cycle at the given condition. This process stabilizes the refrigeration system, enhanced its function, and enabled the system to work under higher condenser temperatures.

  13. Mechanism of H2S-mediated protection against oxidative stress in Escherichia coli.

    Science.gov (United States)

    Mironov, Alexander; Seregina, Tatyana; Nagornykh, Maxim; Luhachack, Lyly G; Korolkova, Natalya; Lopes, Liubov Errais; Kotova, Vera; Zavilgelsky, Gennady; Shakulov, Rustem; Shatalin, Konstantin; Nudler, Evgeny

    2017-06-06

    Endogenous hydrogen sulfide (H2S) renders bacteria highly resistant to oxidative stress, but its mechanism remains poorly understood. Here, we report that 3-mercaptopyruvate sulfurtransferase (3MST) is the major source of endogenous H2S in Escherichia coli Cellular resistance to H2O2 strongly depends on the activity of mstA, a gene that encodes 3MST. Deletion of the ferric uptake regulator (Fur) renders ∆mstA cells hypersensitive to H2O2 Conversely, induction of chromosomal mstA from a strong pLtetO-1 promoter (P tet -mstA) renders ∆fur cells fully resistant to H2O2 Furthermore, the endogenous level of H2S is reduced in ∆fur or ∆sodA ∆sodB cells but restored after the addition of an iron chelator dipyridyl. Using a highly sensitive reporter of the global response to DNA damage (SOS) and the TUNEL assay, we show that 3MST-derived H2S protects chromosomal DNA from oxidative damage. We also show that the induction of the CysB regulon in response to oxidative stress depends on 3MST, whereas the CysB-regulated l-cystine transporter, TcyP, plays the principle role in the 3MST-mediated generation of H2S. These findings led us to propose a model to explain the interplay between l-cysteine metabolism, H2S production, and oxidative stress, in which 3MST protects E. coli against oxidative stress via l-cysteine utilization and H2S-mediated sequestration of free iron necessary for the genotoxic Fenton reaction.

  14. Phosphorylation of Histone H2AX in the Mouse Brain from Development to Senescence

    Directory of Open Access Journals (Sweden)

    Serena Barral

    2014-01-01

    Full Text Available Phosphorylation of the histone H2AX (γH2AX form is an early response to DNA damage and a marker of aging and disease in several cells and tissues outside the nervous system. Little is known about in vivo phosphorylation of H2AX in neurons, although it was suggested that γH2AX is an early marker of neuronal endangerment thus opening the possibility to target it as a neuroprotective strategy. After experimental labeling of DNA-synthesizing cells with 5-bromo-2-deoxyuridine (BrdU, we studied the brain occurrence of γH2AX in developing, postnatal, adult and senescent (2 years mice by light and electron microscopic immunocytochemistry and Western blotting. Focal and/or diffuse γH2AX immunostaining appears in interkinetic nuclei, mitotic chromosomes, and apoptotic nuclei. Immunoreactivity is mainly associated with neurogenetic areas, i.e., the subventricular zone (SVZ of telencephalon, the cerebellar cortex, and, albeit to a much lesser extent, the subgranular zone of the hippocampal dentate gyrus. In addition, γH2AX is highly expressed in the adult and senescent cerebral cortex, particularly the piriform cortex. Double labeling experiments demonstrate that γH2AX in neurogenetic brain areas is temporally and functionally related to proliferation and apoptosis of neuronal precursors, i.e., the type C transit amplifying cells (SVZ and the granule cell precursors (cerebellum. Conversely, γH2AX-immunoreactive cortical neurons incorporating the S phase-label BrdU do not express the proliferation marker phosphorylated histone H3, indicating that these postmitotic cells undergo a significant DNA damage response. Our study paves the way for a better comprehension of the role of H2AX phosphorylation in the normal brain, and offers additional data to design novel strategies for the protection of neuronal precursors and mature neurons in central nervous system (CNS degenerative diseases.

  15. In Vivo Monitoring of H2O2 with Polydopamine and Prussian Blue-coated Microelectrode.

    Science.gov (United States)

    Li, Ruixin; Liu, Xiaomeng; Qiu, Wanling; Zhang, Meining

    2016-08-02

    In vivo monitoring of hydrogen peroxide (H2O2) in the brain is of importance for understanding the function of both reactive oxygen species (ROS) and signal transmission. Producing a robust microelectrode for in vivo measurement of H2O2 is challenging due to the complex brain environment and the instability of electrocatalysts employed for the reduction of H2O2. Here, we develop a new kind of microelectrode for in vivo monitoring of H2O2, which is prepared by, first, electrodeposition of Prussian blue (PB) onto carbon nanotube (CNT) assembled carbon fiber microelectrodes (CFEs) and then overcoating of the CFEs with a thin membrane of polydopamine (PDA) through self-polymerization. Scanning electron microscopic and X-ray proton spectroscopic results confirm the formation of PDA/PB/CNT/CFEs. The PDA membrane enables PB-based electrodes to show high stability in both in vitro and in vivo studies and to stably catalyze the electrochemical reduction of H2O2. The microelectrode is selective for in vivo measurements of H2O2, interference-free from O2 and other electroactive species coexisting in the brain. These properties, along with good linearity, high biocompatibility, and stability toward H2O2, substantially enable the microelectrode to track H2O2 changes in vivo during electrical stimulation and microinfusion of H2O2 and drug, which demonstrates that the microelectrode could be well suited for in vivo monitoring of dynamic changes of H2O2 in rat brain.

  16. Cosmetic wastewater treatment by the ZVI/H2O2 process.

    Science.gov (United States)

    Bogacki, Jan; Marcinowski, Piotr; Zapałowska, Ewa; Maksymiec, Justyna; Naumczyk, Jeremi

    2017-10-01

    The ZVI/H2O2 process was applied for cosmetic wastewater treatment. Two commercial zero-valent iron (ZVI) types with different granulations were chosen: Hepure Ferrox PRB and Hepure Ferrox Target. In addition, the pH and stirring method influence on ZVI/H2O2 process efficiency was studied. During the ZVI and ZVI/H2O2 processes, linear Fe ions concentration increase was observed. The addition of H2O2 significantly accelerated the iron dissolution process. The highest COD removal was obtained using finer ZVI (Hepure Ferrox Target) for doses of reagents ZVI/H2O2 1500/1600 mg/L, in a H2O2/COD weight ratio 2:1, at pH 3.0 with stirring on a magnetic stirrer. After 120 min of the process, 84.0% COD removal (from 796 to 127 mg/L) was achieved. It was found that the efficiency of the process depends, as in the case of the Fenton process, on the ratio of the reagents (ZVI/H2O2) and their dose in relation to the COD (H2O2/COD) but does not depend on the dose of the iron itself. Statistical analysis confirms that COD removal efficiency depends primarily on H2O2/COD ratio and ZVI granulation, but ZVI dose influence is not statistically significant. The head space, solid-phase microextraction, gas chromatography, mass spectrometry results confirm high efficiency of the ZVI/H2O2 process.

  17. Photodegradation of amoxicillin by catalyzed Fe3+/H2O2 process.

    Science.gov (United States)

    Li, Xiaoming; Shen, Tingting; Wang, Dongbo; Yue, Xiu; Liu, Xian; Yang, Qi; Cao, Jianbin; Zheng, Wei; Zeng, Guangming

    2012-01-01

    Three oxidation processes of UV-Fe3+(EDTA)/H2O2 (UV: ultraviolet light; EDTA: ethylenediaminetetraacetic acid), UV-Fe3+/H2O2 and Fe3+/H2O2 were simultaneously investigated for the degradation of amoxicillin at pH 7.0. The results indicated that, 100% amoxicillin degradation and 81.9% chemical oxygen demand (COD(Cr)) removal could be achieved in the UV-Fe3+ (EDTA)/H2O2 process. The treatment efficiency of amoxicillin and COD(Cr) removal were found to decrease to 59.0% and 43.0% in the UV-Fe3+/H2O2 process; 39.6% and 31.3% in the Fe3+/H2O2 process. Moreover, the results of biodegradability (biological oxygen demand (BOD5)/COD(Cr) ratio) revealed that the UV-Fe3+ (EDTA)/H2O2 process was a promising strategy to degrade amoxicillin as the biodegradability of the effluent was improved to 0.45, compared with the cases of UV-Fe3+/H2O2 (0.25) and Fe3+/H2O2 (0.10) processes. Therefore, it could be deduced that EDTA and UV light performed synergetic catalytic effect on the Fe3+/H2O2 process, enhancing the treatment efficiency. The degradation mechanisms were also investigated via UV-Vis spectra, and high performance liquid chromatography-mass spectra. The degradation pathway of amoxicillin was further proposed.

  18. Phospho-histone H2AX is a diagnostic and prognostic marker for epithelial ovarian cancer.

    Science.gov (United States)

    Mei, Ling; Hu, Qian; Peng, Jing; Ruan, Jiaying; Zou, Juan; Huang, Qin; Liu, Shanling; Wang, He

    2015-01-01

    Histone H2AX phosphorylation is a sensitive marker for DSB which contributes to both genomic instability and cancer treatment. Monitoring its formation may be a sensitive means to monitor cancer progression and treatment effect. To define the role of phospho-H2AX (pH2AX) expression in development and prognosis of epithelial ovarian cancer (EOC). The expression of pH2AX in 87 EOC samples and 28 samples of normal ovarian tissues were examined by immunohistochemistry (IHC). The results were semi-quantitatively scored and analyzed by chi-square test. The overall survival time (OS) and disease free interval (DFI) were collected by follow-up and analyzed by Kaplan-Meier analysis. The expression level of pH2AX protein in EOC were higher than that in normal tissues (P<0.001). Among the sensitive cases, high expression of pH2AX was found in 53.2% cases while for resistant cases, high expression rate was 80% (P=0.025). However, pH2AX expression was not significantly correlated with age, histopathological type, tumor differentiation, lymph node metastasis or FIGO stages. Kaplan-Meier analysis found that DFI was negatively correlated with the pH2AX expression, where higher expression of pH2AX resulted in shorter DFI while no OS difference was detected in our study. pH2AX may be used to detect EOC at an early stage and identify women at higher risk for relapse.

  19. Characterization and kinetic analysis of protein tyrosine phosphatase-H2 from Microplitis demolitor bracovirus.

    Science.gov (United States)

    Eum, Jai-Hoon; Bottjen, Rachel C; Pruijssers, Andrea J; Clark, Kevin D; Strand, Michael R

    2010-09-01

    The polydnavirus Microplitis demolitor bracovirus (MdBV) encodes 13 genes that share homology with classical protein tyrosine phosphatases (PTPs). Prior sequence analysis suggested that five members of the MdBV PTP gene family (ptp-H2, -H3, -H5, -N1 and -N2) encode PTPs, seven family members encode pseudophosphatases, and one family member is a pseudogene. Prior experimental studies further implicated PTP-H2 in disabling the function of host hemocytes following infection by MdBV. Here we report expression of PTP-H2 and selected mutants in Escherichia coli cells as non-fusion or thioredoxin-fusion proteins. Following purification by nickel affinity chromatography, the full-length and mutant proteins ran as single bands of predicted size on SDS-PAGE gels under reducing conditions. The non-fusion form of PTP-H2 exhibited classical Michaelis-Menten kinetics using the phosphopeptide END(pY)INASL and difluoro-4-methylumbiliferyl phosphate (DiFMUP) as substrates. As expected, the non-fusion mutant PTP-H2(C236S) had no enzymatic activity, while the thioredoxin-fusion form of PTP-H2 had low levels of activity. PTP-H2 exhibited optimal activity at pH 4.0 and 26 degrees C in sodium acetate buffer, and its activity was diminished by increasing buffer ionic strength. Activity was also greatly reduced by the presence of copper, heparin, and the classical PTP inhibitor vanadate. Using an anti-PTP-H2 antibody, immunoblotting and immunocytochemical studies only detected PTP-H2 in hemocytes from MdBV-infected Pseudoplusia includens. Overall, our results indicate that PTP-H2 is a functional tyrosine phosphatase that is specifically expressed in MdBV-infected hemocytes. Copyright 2010 Elsevier Ltd. All rights reserved.

  20. Solubility of water in lunar basalt at low pH2O

    Science.gov (United States)

    Newcombe, M. E.; Brett, A.; Beckett, J. R.; Baker, M. B.; Newman, S.; Guan, Y.; Eiler, J. M.; Stolper, E. M.

    2017-03-01

    We report the solubility of water in Apollo 15 basaltic "Yellow Glass" and an iron-free basaltic analog composition at 1 atm and 1350 °C. We equilibrated melts in a 1-atm furnace with flowing H2/CO2 gas mixtures that spanned ∼8 orders of magnitude in fO2 (from three orders of magnitude more reducing than the iron-wüstite buffer, IW-3.0, to IW+4.8) and ∼4 orders of magnitude in pH2/pH2O (from 0.003 to 24). Based on Fourier transform infrared spectroscopy (FTIR), our quenched experimental glasses contain 69-425 ppm total water (by weight). Our results demonstrate that under the conditions of our experiments: (1) hydroxyl is the only H-bearing species detected by FTIR; (2) the solubility of water is proportional to the square root of pH2O in the furnace atmosphere and is independent of fO2 and pH2/pH2O; (3) the solubility of water is very similar in both melt compositions; (4) the concentration of H2 in our iron-free experiments is critical vapor volume fraction thought to be required for magma fragmentation (∼65-75 vol.%) at a total pressure of ∼5 bar (corresponding to a depth beneath the lunar surface of ∼120 m). At a fragmentation pressure of ∼5 bar, the calculated vapor composition is dominated by H2, supporting the hypothesis that H2, rather than CO, was the primary propellant of the lunar fire fountain eruptions. The results of our batch degassing model suggest that initial melt compositions with >∼200 ppm C would be required for the vapor composition to be dominated by CO rather than H2 at 65-75% vesicularity.

  1. Increased H2CO production in the outer disk around HD 163296

    Science.gov (United States)

    Carney, M. T.; Hogerheijde, M. R.; Loomis, R. A.; Salinas, V. N.; Öberg, K. I.; Qi, C.; Wilner, D. J.

    2017-09-01

    Context. The gas and dust in circumstellar disks provide the raw materials to form planets. The study of organic molecules and their building blocks in such disks offers insight into the origin of the prebiotic environment of terrestrial planets. Aims: We aim to determine the distribution of formaldehyde, H2CO, in the disk around HD 163296 to assess the contribution of gas- and solid-phase formation routes of this simple organic. Methods: Three formaldehyde lines were observed (H2CO 303-202, H2CO 322-221, and H2CO 321-220) in the protoplanetary disk around the Herbig Ae star HD 163296 with ALMA at 0.5″ (60 AU) spatial resolution. Different parameterizations of the H2CO abundance were compared to the observed visibilities, using either a characteristic temperature, a characteristic radius or a radial power law index to describe the H2CO chemistry. Similar models were applied to ALMA Science Verification data of C18O. In each scenario, χ2 minimization on the visibilities was used to determine the best-fit model in each scenario. Results: H2CO 303-202 was readily detected via imaging, while the weaker H2CO 322-221 and H2CO 321-220 lines required matched filter analysis to detect. H2CO is present throughout most of the gaseous disk, extending out to 550 AU. An apparent 50 AU inner radius of the H2CO emission is likely caused by an optically thick dust continuum. The H2CO radial intensity profile shows a peak at 100 AU and a secondary bump at 300 AU, suggesting increased production in the outer disk. In all modeling scenarios, fits to the H2CO data show an increased abundance in the outer disk. The overall best-fit H2CO model shows a factor of two enhancement beyond a radius of 270 ± 20 AU, with an inner abundance (relative to H2) of 2 - 5 × 10-12. The H2CO emitting region has a lower limit on the kinetic temperature of T> 20 K. The C18O modeling suggests an order of magnitude depletion of C18O in the outer disk and an abundance of 4 - 12 × 10-8 in the inner disk

  2. Ab initio studies of O2-(H2O)n and O3-(H2O)n anionic molecular clusters, n≤12

    DEFF Research Database (Denmark)

    Bork, Nicolai Christian; Kurtén, T.; Enghoff, Martin Andreas Bødker

    2011-01-01

    An ab initio study of gaseous clusters of O2− and O2− with water is presented. Based on thorough scans of configurational space, we determine the thermodynamics of cluster growth. The results are in good agreement with benchmark computational methods and existing experimental data. We find...... that anionic O2−(H2O)n and O3−(H2O)n clusters are thermally stabilized at typical atmospheric conditions for at least n = 5. The first 4 water molecules are strongly bound to the anion due to delocalization of the excess charge while stabilization of more than 4 H2O is due to normal hydrogen bonding. Although...... clustering up to 12 H2O, we find that the O2 and O3 anions retain at least ca. 80 % of the charge and are located at the surface of the cluster. The O2− and O3− speicies are thus accessible for further reactions. Finally, the thermodynamics of a few relevant cluster reactions are considered....

  3. Submillimeter H2O and H2O+emission in lensed ultra- and hyper-luminous infrared galaxies at z 2-4

    NARCIS (Netherlands)

    Yang, C.; Omont, A.; Beelen, A.; González-Alfonso, E.; Neri, R.; Gao, Y.; van der Werf, P.; Weiß, A.; Gavazzi, R.; Falstad, N.; Baker, A. J.; Bussmann, R. S.; Cooray, A.; Cox, P.; Dannerbauer, H.; Dye, S.; Guélin, M.; Ivison, R.; Krips, M.; Lehnert, M.; Michałowski, M. J.; Riechers, D. A.; Spaans, M.; Valiante, E.

    2016-01-01

    We report rest-frame submillimeter H2O emission line observations of 11 ultra- or hyper-luminous infrared galaxies (ULIRGs or HyLIRGs) at z 2-4 selected among the brightest lensed galaxies discovered in the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS). Using the IRAM NOrthern

  4. Reaction kinetics for the synthesis of methanol from CO and H2 on a copper catalyst = Reaktionskinetik der methanolsynthese aus CO und H2 auf einem kupferkatalysator

    NARCIS (Netherlands)

    Kuczynski, M.; Browne, W.I.; Fontein, H.J.; Westerterp, K.R.

    1987-01-01

    The kinetics for the low-pressure synthesis of methanol from CO and H2 were studied in a small integral reactor. The mole fraction of CO was varied from 0.1 to 0.54, the total pressure from 3 to 9 MPa and the temperature from 483 to 545 K. Using the maximum likelihood approach, seventeen possible

  5. Redetermination of Ce[B5O8(OH(H2O]NO3·2H2O

    Directory of Open Access Journals (Sweden)

    Ya-Xi Huang

    2012-05-01

    Full Text Available The crystal structure of Ce[B5O8(OH(H2O]NO3·2H2O, cerium(III aquahydroxidooctaoxidopentaborate nitrate dihydrate, has been redetermined from single-crystal X-ray diffraction data. In contrast to the previous determination [Li et al. (2003. Chem. Mater. 15, 2253–2260], the present study reveals the location of all H atoms, slightly different fundamental building blocks (FBBs of the polyborate anions, more reasonable displacement ellipsoids for all non-H atoms, as well as a model without disorder of the nitrate anion. The crystal structure is built from corrugated polyborate layers parallel to (010. These layers, consisting of [B5O8(OH(H2O]2− anions as FBBs, stack along [010] and are linked by Ce3+ ions, which exhibit a distorted CeO10 coordination sphere. The layers are additionally stabilized via O—H...O hydrogen bonds between water molecules and nitrate anions, located at the interlayer space. The [BO3(H2O]-group shows a [3 + 1] coordination and is considerably distorted from a tetrahedral configuration. Bond-valence-sum calculation shows that the valence sum of boron is only 2.63 valence units (v.u. when the contribution of the water molecule (0.49 v.u. is neglected.

  6. Importance of electrostatic interactions in the association of intrinsically disordered histone chaperone Chz1 and histone H2A.Z-H2B.

    Directory of Open Access Journals (Sweden)

    Xiakun Chu

    Full Text Available Histone chaperones facilitate assembly and disassembly of nucleosomes. Understanding the process of how histone chaperones associate and dissociate from the histones can help clarify their roles in chromosome metabolism. Some histone chaperones are intrinsically disordered proteins (IDPs. Recent studies of IDPs revealed that the recognition of the biomolecules is realized by the flexibility and dynamics, challenging the century-old structure-function paradigm. Here we investigate the binding between intrinsically disordered chaperone Chz1 and histone variant H2A.Z-H2B by developing a structure-based coarse-grained model, in which Debye-Hückel model is implemented for describing electrostatic interactions due to highly charged characteristic of Chz1 and H2A.Z-H2B. We find that major structural changes of Chz1 only occur after the rate-limiting electrostatic dominant transition state and Chz1 undergoes folding coupled binding through two parallel pathways. Interestingly, although the electrostatic interactions stabilize bound complex and facilitate the recognition at first stage, the rate for formation of the complex is not always accelerated due to slow escape of conformations with non-native electrostatic interactions at low salt concentrations. Our studies provide an ionic-strength-controlled binding/folding mechanism, leading to a cooperative mechanism of "local collapse or trapping" and "fly-casting" together and a new understanding of the roles of electrostatic interactions in IDPs' binding.

  7. [Cryogenic Raman spectroscopic characteristics of NaCl-H2O, CaCl2-H2O and NaCl-CaCl2-H2O: application to analysis of fluid inclusions].

    Science.gov (United States)

    Mao, Cui; Chen, Yong; Zhou, Yao-Qi; Ge, Yun-Jin; Zhou, Zhen-Zhu; Wang, You-Zhi

    2010-12-01

    Accurately diagnosing the types of the salt and calculating the salinity quantitatively are the significant content of fluid inclusions. The traditional method of testing fluid inclusions salinity is cooling. To overcome the difficulty for observing freezing phase transition, the authors tested the spectrum of NaCl-H2O, CaCl2-H2O and NaCl-CaCl2-H2O systems at -180 degrees C by laser Raman spectroscopy. The result demonstrates that the ratio of peak values has linear relationship with salinity. Calibration curves were established by typical ratio of hydro-halite at 3 420 cm(-1) to the ice at 3 092 cm(-1), and the ratio of antarcticite at 3 432 cm(-1) to the ice at 3 092 cm(-1). The calibration curves have very high correlation coefficient. This method is verified by synthetic hydrocarbon-bearing aqueous fluid inclusions and quartz aqueous fluid inclusions of well Fengshen 6 in Dongying sag. The results of the authors' experiments show that cryogenic Raman spectroscopy can not only identify the types of the salts but also determine the salinity effectively in fluid inclusions.

  8. NLP modeling for the optimization of LiBr-H2O absorption refrigeration systems with exergy loss rate, heat transfer area, and cost as single objective functions

    DEFF Research Database (Denmark)

    Mussati, Sergio F.; Gernaey, Krist; Morosuk, Tatiana

    2016-01-01

    Based on a nonlinear mathematical programming model, the sizes and operating conditions of the process units of single-effect absorption refrigeration systems operating with a LiBr–H