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Sample records for akademie vd cesk

  1. [Toxoplasma gondii antibodies in pregnant women in the Ceské Budĕjovice District].

    PubMed

    Hejlícek, K; Literák, I; Vostalová, E; Kresnicka, J

    1999-08-01

    In 1984-1986 in the district of Ceské Budĕjovice in the southern part of the Czech Republic pregnant women were subjected to serological examinations for antibodies against Toxoplasma gondii. A total of 3,392 women were examined within the age bracket 16-54 years. For the serological examination parallel examinations were made using Sabin-Feldman test (SFT) and the complement fixation test (CFT). In SFT the basic serum dilution was 1:4, in CFT 1:10. Pregnant women were examined once or repeatedly. During the first examination which was usually made between the second and third month of pregnancy the total (SFT and CFT) prevalence was 37%. In the SFT antibodies were detected in 35%, in CFT in 25%. The second blood sample was taken during the 4th-5th month of pregnancy and subsequent samples during the 8th-9th month of pregnancy. In women who were examined twice or repeatedly (a total of 1,409 women), the dynamics of prevalence of antibodies were recorded. 64% women were permanently negative, 33% women were permanently positive with the same or a slightly varying titre and in 3% women during pregnancy, seroconversion was observed or a significant rise of antibodies. In 20 women where seroconversion or a significant rise of antibodies was found data were collected to find out whether in their children from birth to the age of 12-13 years toxoplasmosis was diagnosed. The toxoplasmosis was not diagnosed in these children.

  2. VD--Epidemic Among Teenagers. Public Affairs Pamphlet No. 517.

    ERIC Educational Resources Information Center

    Saltman, Jules

    This booklet discusses the venereal disease (VD) epidemic among teenagers. After presenting some basic facts about VD, the effect, treatment, and prevention of both gonorrhea and syphilis is discussed. The booklet then examines statistics concerning gonorrhea and syphilis. It also looks at why the VD epidemic exists and includes discussions on (1)…

  3. [Application of the recombinant protein MOMP(VD2-VD3) from Chlamydia pneumoniae in sero diagnosis].

    PubMed

    Zhou, Zhou; Wu, Yi-mou; Liu, Jie; Chen, Chao-qun; Yang, Ling

    2007-06-01

    To express the recombinant protein MOMP(VD2-VD3) of Chlamydia pneumoniae, and research on the immunocompetence of the MOMP(VD2-VD3) to support serodiagnosis,PCR and gene recombinant technique was used to clone the targeted DNA fragment from a strain AR-39. The recombinant plasmid was induced in E. coli BL21 after having constructed the prokaryotic expression system, then the immunocompetence of the expression product was analyzed by Western blot and indirected ELISA which is based on the animal experimentation. A group of control sera and 126 sera from patients with coronary heart disease were examined by using ELISAs based on the recombinant protein (MOMP(VD2-VD3), and then the results were evaluated comparing with a commercial ELISAs kit. The results of the Western blot and indirected ELISA showed ompA(VD2-VD3) gene inserted in pET30a could express a recombinant protein with the molecular weight of 24kDa in BL21 and specifically reacted with the antibodies against the MOMP. Specific humoral response was elicited after immune the BALB/c mouse with protein and the specific antibody titer was more than 1:20480. Using a panel of control sera, the participation of the recombinant antigen, the sensitivity and the specificity of the indirected ELISAs were 100% respectively. Comparisons between two methods in detecting 126 sero samples, the concordance of two tests was 96.3%. The results reported here show that the recombinant protein with excellent immunocompetence could benefit the research on the serodiagnosis to Chlamydia pneumoniae. PMID:17672316

  4. Hyphopodium-Specific VdNoxB/VdPls1-Dependent ROS-Ca2+ Signaling Is Required for Plant Infection by Verticillium dahliae

    PubMed Central

    Zhao, Yun-Long; Zhou, Ting-Ting; Guo, Hui-Shan

    2016-01-01

    Verticillium dahliae is a phytopathogenic fungus obligate in root infection. A few hyphopodia differentiate from large numbers of hyphae after conidia germination on the root surface for further infection. However, the molecular features and role of hyphopodia in the pathogenicity of V. dahliae remain elusive. In this study, we found that the VdPls1, a tetraspanin, and the VdNoxB, a catalytic subunit of membrane-bound NADPH oxidases for reactive oxygen species (ROS) production, were specifically expressed in hyphopodia. VdPls1 and VdNoxB highly co-localize with the plasma membrane at the base of hyphopodia, where ROS and penetration pegs are generated. Mutant strains, VdΔnoxb and VdΔpls1, in which VdPls1 and VdNoxB were deleted, respectively, developed defective hyphpodia incapable of producing ROS and penetration pegs. Defective plasma membrane localization of VdNoxB in VdΔpls1 demonstrates that VdPls1 functions as an adaptor protein for the recruitment and activation of the VdNoxB. Furthermore, in VdΔnoxb and VdΔpls1, tip-high Ca2+ accumulation was impaired in hyphopodia, but not in vegetative hyphal tips. Moreover, nuclear targeting of VdCrz1 and activation of calcineurin-Crz1 signaling upon hyphopodium induction in wild-type V. dahliae was impaired in both knockout mutants, indicating that VdPls1/VdNoxB-dependent ROS was specifically required for tip-high Ca2+ elevation in hyphopodia to activate the transcription factor VdCrz1 in the regulation of penetration peg formation. Together with the loss of virulence of VdΔnoxb and VdΔpls1, which are unable to initiate colonization in cotton plants, our data demonstrate that VdNoxB/VdPls1-mediated ROS production activates VdCrz1 signaling through Ca2+ elevation in hyphopodia, infectious structures of V. dahliae, to regulate penetration peg formation during the initial colonization of cotton roots. PMID:27463643

  5. Identification and characterization of a pathogenicity-related gene VdCYP1 from Verticillium dahliae.

    PubMed

    Zhang, Dan-Dan; Wang, Xin-Yan; Chen, Jie-Yin; Kong, Zhi-Qiang; Gui, Yue-Jing; Li, Nan-Yang; Bao, Yu-Ming; Dai, Xiao-Feng

    2016-01-01

    Verticillium dahliae is a phytopathogenic fungus that causes vascular wilt disease in a wide variety of crop plants, thereby causing extensive economic loss. In present study, one V. dahliae T-DNA mutant M01C06 showed the pathogenicity loss on cotton, and the expression of a flanking gene encoding cytochrome P450 monooxygenase (P450, VdCYP1) was strongly repressed. P450s of fungi could affect the fungal pathogenicity by involving in the synthesis of secondary metabolites. However, there was no report about the pathogenic function of P450s in V. dahliae. VdCYP1 gene deletion and complementation experiments confirmed that VdCYP1 was the pathogenicity-related gene in V. dahliae. A comparison of culture supernatants of the VdCYP1 deletion mutants and wild-type strains indicates that at least 14 kinds of secondary metabolites syntheses were affected due to VdCYP1 gene deletion. One of these compounds, sulfacetamide, had the ability to induce the necrosis and wilting symptoms in cotton. Above results indicate that VdCYP1 could participate in pathogenesis by involving the secondary metabolism in V. dahliae, such as the compound sulfacetamide. In conclusion, VdCYP1 acts as an important pathogenicity-related factor to involve in secondary metabolism that likely contributes to the pathogenic process in V. dahliae. PMID:27329129

  6. Identification and characterization of a pathogenicity-related gene VdCYP1 from Verticillium dahliae

    PubMed Central

    Zhang, Dan-Dan; Wang, Xin-Yan; Chen, Jie-Yin; Kong, Zhi-Qiang; Gui, Yue-Jing; Li, Nan-Yang; Bao, Yu-Ming; Dai, Xiao-Feng

    2016-01-01

    Verticillium dahliae is a phytopathogenic fungus that causes vascular wilt disease in a wide variety of crop plants, thereby causing extensive economic loss. In present study, one V. dahliae T-DNA mutant M01C06 showed the pathogenicity loss on cotton, and the expression of a flanking gene encoding cytochrome P450 monooxygenase (P450, VdCYP1) was strongly repressed. P450s of fungi could affect the fungal pathogenicity by involving in the synthesis of secondary metabolites. However, there was no report about the pathogenic function of P450s in V. dahliae. VdCYP1 gene deletion and complementation experiments confirmed that VdCYP1 was the pathogenicity-related gene in V. dahliae. A comparison of culture supernatants of the VdCYP1 deletion mutants and wild-type strains indicates that at least 14 kinds of secondary metabolites syntheses were affected due to VdCYP1 gene deletion. One of these compounds, sulfacetamide, had the ability to induce the necrosis and wilting symptoms in cotton. Above results indicate that VdCYP1 could participate in pathogenesis by involving the secondary metabolism in V. dahliae, such as the compound sulfacetamide. In conclusion, VdCYP1 acts as an important pathogenicity-related factor to involve in secondary metabolism that likely contributes to the pathogenic process in V. dahliae. PMID:27329129

  7. Isolation and functional analysis of the pathogenicity-related gene VdPR3 from Verticillium dahliae on cotton.

    PubMed

    Zhang, Ya-Lin; Li, Zhi-Fang; Feng, Zi-Li; Feng, Hong-Jie; Zhao, Li-Hong; Shi, Yong-Qiang; Hu, Xiao-Ping; Zhu, He-Qin

    2015-11-01

    The fungal plant pathogen Verticillium dahliae is the causal agent of vascular wilt, a disease that can seriously diminish cotton fiber yield. The pathogenicity mechanism and the identity of the genes that interact with cotton during the infection process still remain unclear. In this study, we investigated the low-pathogenic, non-microsclerotium-producing mutant vdpr3 obtained in a previous study from the screening of a T-DNA insertional library of the highly virulent isolate Vd080; the pathogenicity-related gene (VdPR3) in wild-type strain Vd080 was cloned. Knockout mutants (ΔVdPR3) showed lower mycelium growth and obvious reduction in sporulation ability without microsclerotium formation. An evaluation of carbon utilization in mutants and wild-type isolate Vd080 demonstrated that mutants-lacking VdPR3 exhibited decreased cellulase and amylase activities, which was restored in the complementary mutants (ΔVdPR3-C) to levels similar to those of Vd080. ΔVdPR3 postponed infectious events in cotton and showed a significant reduction in pathogenicity. Reintroduction of a functional VdPR3 copy into ΔVdPR3-C restored the ability to infect cotton plants. These results suggest that VdPR3 is a multifunctional gene involved in growth development, extracellular enzyme activity, and virulence of V. dahliae on cotton. PMID:25652159

  8. Isolation and functional analysis of the pathogenicity-related gene VdPR3 from Verticillium dahliae on cotton.

    PubMed

    Zhang, Ya-Lin; Li, Zhi-Fang; Feng, Zi-Li; Feng, Hong-Jie; Zhao, Li-Hong; Shi, Yong-Qiang; Hu, Xiao-Ping; Zhu, He-Qin

    2015-11-01

    The fungal plant pathogen Verticillium dahliae is the causal agent of vascular wilt, a disease that can seriously diminish cotton fiber yield. The pathogenicity mechanism and the identity of the genes that interact with cotton during the infection process still remain unclear. In this study, we investigated the low-pathogenic, non-microsclerotium-producing mutant vdpr3 obtained in a previous study from the screening of a T-DNA insertional library of the highly virulent isolate Vd080; the pathogenicity-related gene (VdPR3) in wild-type strain Vd080 was cloned. Knockout mutants (ΔVdPR3) showed lower mycelium growth and obvious reduction in sporulation ability without microsclerotium formation. An evaluation of carbon utilization in mutants and wild-type isolate Vd080 demonstrated that mutants-lacking VdPR3 exhibited decreased cellulase and amylase activities, which was restored in the complementary mutants (ΔVdPR3-C) to levels similar to those of Vd080. ΔVdPR3 postponed infectious events in cotton and showed a significant reduction in pathogenicity. Reintroduction of a functional VdPR3 copy into ΔVdPR3-C restored the ability to infect cotton plants. These results suggest that VdPR3 is a multifunctional gene involved in growth development, extracellular enzyme activity, and virulence of V. dahliae on cotton.

  9. VdMsb regulates virulence and microsclerotia production in the fungal plant pathogen Verticillium dahliae.

    PubMed

    Tian, Liangliang; Xu, Jun; Zhou, Lei; Guo, Wangzhen

    2014-10-25

    The vascular wilt fungus Verticillium dahliae infects the roots of cotton plants and can seriously diminish the yield and quality of this and other dicotyledons. However, the key genes involved in V. dahliae infection and pathogenesis in cotton remain unclear. Msb encodes a transmembrane mucin that is highly conserved in the MAPK signal pathway. Msb has been implicated previously in pathogenicity in various aerial plant fungi. In this study, V. dahliae Msb (VdMsb) was found to be required for fungal virulence and microsclerotia production. Strains lacking VdMsb exhibited reduced conidiation and microsclerotia formation. Compared with wild-type and gene-complemented strains, the invasive growth and adhesive capacity of VdMsb deletion mutants were significantly decreased. These results suggest that VdMsb plays a role in development and virulence in V. dahliae.

  10. Gravity affects the responsiveness of Runx2 to 1, 25-dihydroxyvitamin D3 (VD3)

    NASA Astrophysics Data System (ADS)

    Guo, Feima; Dai, Zhongquan; Wu, Feng; Liu, Zhaoxia; Tan, Yingjun; Wan, Yumin; Shang, Peng; Li, Yinghui

    2013-03-01

    Bone loss resulting from spaceflight is mainly caused by decreased bone formation, and decreased osteoblast proliferation and differentiation. Transcription factor Runx2 plays an important role in osteoblast differentiation and function by responding to microenvironment changes including cytokine and mechanical factors. The effects of 1, 25-dihydroxyvitamin D3 (VD3) on Runx2 in terms of mechanical competence is far less clear. This study describes how gravity affects the response of Runx2 to VD3. A MC3T3-6OSE2-Luc osteoblast model was constructed in which the activity of Runx2 was reflected by reporter luciferase activity identifed by bone-related cytokines. The results showed that luciferase activity in MC3T3-6OSE2-Luc cells transfected with Runx2 was twice that of the vacant vector. Alkaline phosphatase (ALP) activity was increased in MC3T3-6OSE2-Luc cells by different concentrations of IGF-I and BMP2. MC3T3-6OSE2-Luc cells were cultured under simulated microgravity or centrifuge with or without VD3. In simulated microgravity, luciferase activity was decreased after 48 h of clinorotation culture, but increased in the centrifuge culture. Luciferase activity was increased after VD3 treatment in normal conditions and simulated microgravity, the increase in luciferase activity in simulated microgravity was lower than that in the 1 g condition when simultaneously treated with VD3 and higher than that in the centrifuge condition. Co-immunoprecipitation showed that the interaction between the VD3 receptor (VDR) and Runx2 was decreased by simulated microgravity, but increased by centrifugation. From these results, we conclude that gravity affects the response of Runx2 to VD3 which results from an alteration in the interaction between VDR and Runx2 under different gravity conditions.

  11. VdThit, a Thiamine Transport Protein, Is Required for Pathogenicity of the Vascular Pathogen Verticillium dahliae.

    PubMed

    Qi, Xiliang; Su, Xiaofeng; Guo, Huiming; Qi, Juncang; Cheng, Hongmei

    2016-07-01

    Verticillium dahliae causes a serious wilt disease of important crops and is difficult to control. Few plasma-membrane transport proteins for nutrient acquisition have been identified for this fungus, and their involvement in the disease process is unknown. Here, a plasma-membrane protein, the V. dahliae thiamine transporter protein VdThit, was characterized functionally by deletion of the VdThit gene in V. dahliae. Disruption strains were viable, but growth and conidial germination and production were reduced and virulence was impaired. Interestingly, by supplementing exogenous thiamine, growth, conidiation, and virulence of the VdΔThit mutants were partially restored. Stress-tolerance assays showed that the VdΔThit mutant strains were markedly more susceptible to oxidative stress and UV damage. High-pressure liquid chromatography-mass spectrometry (HPLC-MS) and gas chromatography-mass spectrometry (GC-MS) analyses showed low levels of pyruvate metabolism intermediates acetoin and acetyl coenzyme A (acetyl-CoA) in the VdΔThit mutant strains, suggesting that pyruvate metabolism was suppressed. Expression analysis of VdThit confirmed the importance of VdThit in vegetative growth, reproduction, and invasive hyphal growth. Furthermore, a green fluorescent protein (GFP)-labeled VdΔThit mutant (VdΔThit-7-GFP) was suppressed in initial infection and root colonization, as viewed with light microscopy. Together, these results showed that VdThit plays an indispensable role in the pathogenicity of V. dahliae.

  12. VdThit, a Thiamine Transport Protein, Is Required for Pathogenicity of the Vascular Pathogen Verticillium dahliae.

    PubMed

    Qi, Xiliang; Su, Xiaofeng; Guo, Huiming; Qi, Juncang; Cheng, Hongmei

    2016-07-01

    Verticillium dahliae causes a serious wilt disease of important crops and is difficult to control. Few plasma-membrane transport proteins for nutrient acquisition have been identified for this fungus, and their involvement in the disease process is unknown. Here, a plasma-membrane protein, the V. dahliae thiamine transporter protein VdThit, was characterized functionally by deletion of the VdThit gene in V. dahliae. Disruption strains were viable, but growth and conidial germination and production were reduced and virulence was impaired. Interestingly, by supplementing exogenous thiamine, growth, conidiation, and virulence of the VdΔThit mutants were partially restored. Stress-tolerance assays showed that the VdΔThit mutant strains were markedly more susceptible to oxidative stress and UV damage. High-pressure liquid chromatography-mass spectrometry (HPLC-MS) and gas chromatography-mass spectrometry (GC-MS) analyses showed low levels of pyruvate metabolism intermediates acetoin and acetyl coenzyme A (acetyl-CoA) in the VdΔThit mutant strains, suggesting that pyruvate metabolism was suppressed. Expression analysis of VdThit confirmed the importance of VdThit in vegetative growth, reproduction, and invasive hyphal growth. Furthermore, a green fluorescent protein (GFP)-labeled VdΔThit mutant (VdΔThit-7-GFP) was suppressed in initial infection and root colonization, as viewed with light microscopy. Together, these results showed that VdThit plays an indispensable role in the pathogenicity of V. dahliae. PMID:27089469

  13. Exact kinetic energy enables accurate evaluation of weak interactions by the FDE-vdW method

    SciTech Connect

    Sinha, Debalina; Pavanello, Michele

    2015-08-28

    The correlation energy of interaction is an elusive and sought-after interaction between molecular systems. By partitioning the response function of the system into subsystem contributions, the Frozen Density Embedding (FDE)-vdW method provides a computationally amenable nonlocal correlation functional based on the adiabatic connection fluctuation dissipation theorem applied to subsystem density functional theory. In reproducing potential energy surfaces of weakly interacting dimers, we show that FDE-vdW, either employing semilocal or exact nonadditive kinetic energy functionals, is in quantitative agreement with high-accuracy coupled cluster calculations (overall mean unsigned error of 0.5 kcal/mol). When employing the exact kinetic energy (which we term the Kohn-Sham (KS)-vdW method), the binding energies are generally closer to the benchmark, and the energy surfaces are also smoother.

  14. VdCrz1 is involved in microsclerotia formation and required for full virulence in Verticillium dahliae.

    PubMed

    Xiong, Dianguang; Wang, Yonglin; Tang, Chen; Fang, Yulin; Zou, Jingyi; Tian, Chengming

    2015-09-01

    Calcium signaling plays crucial roles in ion stress tolerance, sporulation and pathogenicity in fungi. Although the signaling pathway mediated by calcineurin and the calcineurin-responsive zinc finger transcription factor Crz1 is well characterized in other fungi, this pathway is not well characterized in the phytopathogenic fungus, Verticillium dahliae. To better understand the role of this calcineurin-dependent transcription factor in V. dahliae, an ortholog of CRZ1, VdCrz1, was identified and characterized functionally. Transcriptional analysis of VdCrz1 and GFP expression driven by the VdCrz1 promoter indicated that VdCrz1 was involved in microsclerotia development. After targeted deletion of VdCrz1, microsclerotia formation and melanin accumulation were impaired. Furthermore, the ΔVdCrz1 mutants were hypersensitive to high concentrations of Ca(2+) and cell wall-perturbing agents, such as sodium dodecyl sulfate. The addition of Mg(2+) to the medium restores the microsclerotia formation in ΔVdCrz1 mutants. The ΔVdCrz1 mutants exhibited delayed Verticillium wilt symptoms on smoke tree. These results suggest that VdCrz1 plays important roles in Ca(2+) signaling, cell wall integrity, microsclerotia development and full virulence in V. dahliae.

  15. mBEEF-vdW: Robust fitting of error estimation density functionals

    NASA Astrophysics Data System (ADS)

    Lundgaard, Keld T.; Wellendorff, Jess; Voss, Johannes; Jacobsen, Karsten W.; Bligaard, Thomas

    2016-06-01

    We propose a general-purpose semilocal/nonlocal exchange-correlation functional approximation, named mBEEF-vdW. The exchange is a meta generalized gradient approximation, and the correlation is a semilocal and nonlocal mixture, with the Rutgers-Chalmers approximation for van der Waals (vdW) forces. The functional is fitted within the Bayesian error estimation functional (BEEF) framework [J. Wellendorff et al., Phys. Rev. B 85, 235149 (2012), 10.1103/PhysRevB.85.235149; J. Wellendorff et al., J. Chem. Phys. 140, 144107 (2014), 10.1063/1.4870397]. We improve the previously used fitting procedures by introducing a robust MM-estimator based loss function, reducing the sensitivity to outliers in the datasets. To more reliably determine the optimal model complexity, we furthermore introduce a generalization of the bootstrap 0.632 estimator with hierarchical bootstrap sampling and geometric mean estimator over the training datasets. Using this estimator, we show that the robust loss function leads to a 10 % improvement in the estimated prediction error over the previously used least-squares loss function. The mBEEF-vdW functional is benchmarked against popular density functional approximations over a wide range of datasets relevant for heterogeneous catalysis, including datasets that were not used for its training. Overall, we find that mBEEF-vdW has a higher general accuracy than competing popular functionals, and it is one of the best performing functionals on chemisorption systems, surface energies, lattice constants, and dispersion. We also show the potential-energy curve of graphene on the nickel(111) surface, where mBEEF-vdW matches the experimental binding length. mBEEF-vdW is currently available in gpaw and other density functional theory codes through Libxc, version 3.0.0.

  16. VD: is society willing to meet the price of realistic legislation?

    PubMed

    Rozovsky, L E

    1972-12-23

    A significant question at this time is whether there is any rationale for venereal disease (VD) legislation and legislation for all communicable diseases. VD legislation, to be effective, needs to reflect the causes of the spread of the disease. The causes would appear to rest on an increase in sexual activity and indiscriminate sexual activity among vast numbers of people throughout the world rather than an increase in the activity of the disease itself. Causes include increased population mobility and migration, urbanization, higher birthrates increasing the youthful and most sexually active part of the population, the discarding of traditional values, the removal of the fear of pregnancy by modern contraceptives, and a lack of knowledge concerning the nature of VD. Early legislation tried to control at least 1 cause of the spread of VD, i.e., prostitution. Legislation was also directed against homosexuality. 1 method of attacking indiscriminate sexual activity was to legislate against advertisements for curing VD. Legislation has also attempted to control individuals infected by making it an offense to communicate VD. The Criminal Code of Canada and VD regulations throughout the world are illustrative of such efforts. There has been no success in gaining convictions. Clearly, private activities cannot be controlled by law, but a legislative requirement for a premarital examination for VD is realistic since marriage is a public act. To combat the majority of cases, most jurisdictions have chosen compulsory reporting, tracing of contact, and control--all by force of law. Legislation varies from country to country as to what information is reported, to whom and under what conditions, but the basic system in those countries which employ a compulsory contract tracing system is the same in that to a large degree it depends for its success on the private physician. Legislation fails because it has tried to force the private physician to be a public officer. Unrealistic

  17. Band Engineering by Controlling vdW Epitaxy Growth Mode in 2D Gallium Chalcogenides.

    PubMed

    Cai, Hui; Soignard, Emmanuel; Ataca, Can; Chen, Bin; Ko, Changhyun; Aoki, Toshihiro; Pant, Anupum; Meng, Xiuqing; Yang, Shengxue; Grossman, Jeffrey; Ogletree, Frank D; Tongay, Sefaattin

    2016-09-01

    Atomically thin quasi-2D GaSe flakes are synthesized via van der Waals (vdW) epitaxy on a polar Si (111) surface. The bandgap is continuously tuned from its commonly accepted value at 620 down to the 700 nm range, only attained previously by alloying Te into GaSe (GaSex Te1- x ). This is accomplished by manipulating various vdW epitaxy kinetic factors, which allows the choice bet ween screw-dislocation-driven and layer-bylayer growth, and the design of different morphologies with different material-substrate interaction (strain) energies. PMID:27271214

  18. VORFFIP-driven dock: V-D2OCK, a fast and accurate protein docking strategy.

    PubMed

    Segura, Joan; Marín-López, Manuel Alejandro; Jones, Pamela F; Oliva, Baldo; Fernandez-Fuentes, Narcis

    2015-01-01

    The experimental determination of the structure of protein complexes cannot keep pace with the generation of interactomic data, hence resulting in an ever-expanding gap. As the structural details of protein complexes are central to a full understanding of the function and dynamics of the cell machinery, alternative strategies are needed to circumvent the bottleneck in structure determination. Computational protein docking is a valid and valuable approach to model the structure of protein complexes. In this work, we describe a novel computational strategy to predict the structure of protein complexes based on data-driven docking: VORFFIP-driven dock (V-D2OCK). This new approach makes use of our newly described method to predict functional sites in protein structures, VORFFIP, to define the region to be sampled during docking and structural clustering to reduce the number of models to be examined by users. V-D2OCK has been benchmarked using a validated and diverse set of protein complexes and compared to a state-of-art docking method. The speed and accuracy compared to contemporary tools justifies the potential use of VD2OCK for high-throughput, genome-wide, protein docking. Finally, we have developed a web interface that allows users to browser and visualize V-D2OCK predictions from the convenience of their web-browsers.

  19. FDE-vdW: A van der Waals inclusive subsystem density-functional theory

    SciTech Connect

    Kevorkyants, Ruslan; Pavanello, Michele; Eshuis, Henk

    2014-07-28

    We present a formally exact van der Waals inclusive electronic structure theory, called FDE-vdW, based on the Frozen Density Embedding formulation of subsystem Density-Functional Theory. In subsystem DFT, the energy functional is composed of subsystem additive and non-additive terms. We show that an appropriate definition of the long-range correlation energy is given by the value of the non-additive correlation functional. This functional is evaluated using the fluctuation–dissipation theorem aided by a formally exact decomposition of the response functions into subsystem contributions. FDE-vdW is derived in detail and several approximate schemes are proposed, which lead to practical implementations of the method. We show that FDE-vdW is Casimir-Polder consistent, i.e., it reduces to the generalized Casimir-Polder formula for asymptotic inter-subsystems separations. Pilot calculations of binding energies of 13 weakly bound complexes singled out from the S22 set show a dramatic improvement upon semilocal subsystem DFT, provided that an appropriate exchange functional is employed. The convergence of FDE-vdW with basis set size is discussed, as well as its dependence on the choice of associated density functional approximant.

  20. [Trade, wars and the venereal disease: VD epidemic and control of Korea in the late nineteenth and early twentieth century].

    PubMed

    Sihn, Kyu-hwan

    2008-12-01

    This paper examines the spread of venereal disease from the Opening of Korea to the early Japanese colonial period. It focuses on the formation and expansion of Japanese settlement in Korea, the influence of wars, and the state control of VD. The Opening of Korea made the foreign settlement, and Japanese licensed prostitution flourished in Japanese settlement. According to the First Annual Report of the Korean Government Hospital (1886) and Gyelimuisa (1887), VD patients occupied 18.3% of outpatients in Jejungwon hospital of Seoul and 8.9% of outpatients in Busan hospital. Directly after the Opening of Korea, Korean people's VD became lesser critical than Japanese people's VD. But the expansion of Japanese settlement and outbreak of two wars such as Sino-Japanese War and Russo-Japanese War made worse Korean people's VD. According to the Residency-General resources (1904-1909), syphilis patients was registered in 0.8-6.6% (average 3.6%). If it add to gonorrhea and chancroid patients which often could not be found out by the naked eyes, the number of VD patients will be increase. Ji Seok-yeong (1855-1935), the earliest smallpox vaccinarian in Korea, asserted the need of VD control. Though he warned men bought sex as well as prostitutes became the main culprit of VD diffusion, he supported licensed prostitution because of realistic possibility. The Great Han Empire (1897-1910) tried to control the lower grade whore, and gathered prostitutes in some area by police power. After Japanese annexation of Korea, while Japanese has gradually decreased in VD patients, Korean has gradually increased in VD patients. PMID:19174628

  1. VdNUC-2, the Key Regulator of Phosphate Responsive Signaling Pathway, Is Required for Verticillium dahliae Infection.

    PubMed

    Deng, Sheng; Wang, Cai-yue; Zhang, Xin; Wang, Qing; Lin, Ling

    2015-01-01

    In fungal cells, a phosphate (Pi) responsive signaling and metabolism (PHO) pathway regulates Pi-homeostasis. NUC-2/PHO81 and its homologs are one of the most important components in the regulation pathway. In soil-borne phytopathogenic fungus Verticillium dahliae, we identified a Neurospora crassa nuc-2 homolog gene VdNUC-2. VdNUC-2 is composed of 1,018 amino acids, and is highly conserved in tested filamentous fungi. Under conditions of Pi-starvation, compared with the wild-type strain and ectopic complementation strains, the VdNUC-2 knocked out mutants exhibited reduced radial growth, decreased production of conidia and microsclerotia, and were more sensitive to hydrogen peroxide stress. The virulence of VdNUC-2 defective mutants was significantly compromised, and that was unable to be restored by exogenous application of extra Pi. Additionally, the deletion mutants of VdNUC-1, a key transcription factor gene positively controlled by VdNUC-2 in the PHO pathway, showed the similar cultural phenotypes as VdNUC-2 mutants when both of them grew in Pi-limited conditions. However, the virulence of VdNUC-1 mutants was comparable to the wild-type strain. These evidences indicated that the virulence reduction in VdNUC-2 mutants is not due to the interruptions in the PHO pathway or the disturbance of Pi-homeostasis in V. dahliae cytoplasm. VdNUC-2 is not only a crucial gene in the PHO pathway in V. dahliae, but also is required for the full virulence during host-infection.

  2. VdNUC-2, the Key Regulator of Phosphate Responsive Signaling Pathway, Is Required for Verticillium dahliae Infection

    PubMed Central

    Deng, Sheng; Wang, Cai-yue; Zhang, Xin; Wang, Qing; Lin, Ling

    2015-01-01

    In fungal cells, a phosphate (Pi) responsive signaling and metabolism (PHO) pathway regulates Pi-homeostasis. NUC-2/PHO81 and its homologs are one of the most important components in the regulation pathway. In soil-borne phytopathogenic fungus Verticillium dahliae, we identified a Neurospora crassa nuc-2 homolog gene VdNUC-2. VdNUC-2 is composed of 1,018 amino acids, and is highly conserved in tested filamentous fungi. Under conditions of Pi-starvation, compared with the wild-type strain and ectopic complementation strains, the VdNUC-2 knocked out mutants exhibited reduced radial growth, decreased production of conidia and microsclerotia, and were more sensitive to hydrogen peroxide stress. The virulence of VdNUC-2 defective mutants was significantly compromised, and that was unable to be restored by exogenous application of extra Pi. Additionally, the deletion mutants of VdNUC-1, a key transcription factor gene positively controlled by VdNUC-2 in the PHO pathway, showed the similar cultural phenotypes as VdNUC-2 mutants when both of them grew in Pi-limited conditions. However, the virulence of VdNUC-1 mutants was comparable to the wild-type strain. These evidences indicated that the virulence reduction in VdNUC-2 mutants is not due to the interruptions in the PHO pathway or the disturbance of Pi-homeostasis in V. dahliae cytoplasm. VdNUC-2 is not only a crucial gene in the PHO pathway in V. dahliae, but also is required for the full virulence during host-infection. PMID:26670613

  3. VdNUC-2, the Key Regulator of Phosphate Responsive Signaling Pathway, Is Required for Verticillium dahliae Infection.

    PubMed

    Deng, Sheng; Wang, Cai-yue; Zhang, Xin; Wang, Qing; Lin, Ling

    2015-01-01

    In fungal cells, a phosphate (Pi) responsive signaling and metabolism (PHO) pathway regulates Pi-homeostasis. NUC-2/PHO81 and its homologs are one of the most important components in the regulation pathway. In soil-borne phytopathogenic fungus Verticillium dahliae, we identified a Neurospora crassa nuc-2 homolog gene VdNUC-2. VdNUC-2 is composed of 1,018 amino acids, and is highly conserved in tested filamentous fungi. Under conditions of Pi-starvation, compared with the wild-type strain and ectopic complementation strains, the VdNUC-2 knocked out mutants exhibited reduced radial growth, decreased production of conidia and microsclerotia, and were more sensitive to hydrogen peroxide stress. The virulence of VdNUC-2 defective mutants was significantly compromised, and that was unable to be restored by exogenous application of extra Pi. Additionally, the deletion mutants of VdNUC-1, a key transcription factor gene positively controlled by VdNUC-2 in the PHO pathway, showed the similar cultural phenotypes as VdNUC-2 mutants when both of them grew in Pi-limited conditions. However, the virulence of VdNUC-1 mutants was comparable to the wild-type strain. These evidences indicated that the virulence reduction in VdNUC-2 mutants is not due to the interruptions in the PHO pathway or the disturbance of Pi-homeostasis in V. dahliae cytoplasm. VdNUC-2 is not only a crucial gene in the PHO pathway in V. dahliae, but also is required for the full virulence during host-infection. PMID:26670613

  4. The Mitogen-Activated Protein Kinase Kinase VdPbs2 of Verticillium dahliae Regulates Microsclerotia Formation, Stress Response, and Plant Infection

    PubMed Central

    Tian, Longyan; Wang, Yonglin; Yu, Jun; Xiong, Dianguang; Zhao, Hengjun; Tian, Chengming

    2016-01-01

    Verticillium dahliae, a ubiquitous phytopathogenic fungus, forms resting structures, known as microsclerotia that play crucial roles in Verticillium wilt diseases. VdHog1, a mitogen-activated protein kinase (MAPK), controls microsclerotia formation, virulence, and stress response in V. dahliae. In this study, we present detailed evidence that the conserved upstream component of VdHog1, VdPbs2, is a key regulator of microsclerotia formation, oxidative stress and fungicide response and plant virulence in V. dahliae. We identified VdPbs2, homologous to the yeast MAPK kinase Pbs2. Similar to the VdHog1 deletion mutant, VdPbs2 deletion strains exhibited delayed melanin synthesis and reduced formation of microsclerotia. When exposed to stresses, VdPbs2 mutants were more sensitive than the wild type to osmotic agents and peroxide, but more resistant to inhibitors of cell wall synthesis and some fungicides. Finally, VdPbs2 deletion mutants exhibited reduced virulence on smoke tree and tobacco seedlings. When taken together, we implicate that VdPbs2 and VdHog1 function in a cascade that regulates microsclerotia formation and virulence, but not all VdHog1 dependent functions are VdPbs2 regulated. This study thus provides novel insights into the signal transduction mechanisms that regulate microsclerotia formation and pathogenesis in this fungus. PMID:27729908

  5. A novel correction scheme for DFT: A combined vdW-DF/CCSD(T) approach

    NASA Astrophysics Data System (ADS)

    Hermann, Jan; Bludský, Ota

    2013-07-01

    A system-specific but very accurate density functional theory (DFT) correction scheme is proposed for precise calculations of adsorbent-adsorbate interactions by combining the non-empirical van der Waals density functional (vdW-DF) method and the empirical DFT/CC correction scheme to reach accuracy of the coupled clusters method with single, double and perturbative triple excitations (CCSD(T)). The new approach is applied to small molecules (CH4, CO2, H2, H2O, N2) interacting with silica surfaces and purely siliceous microporous solids. The vdW-DF/CC results for a perfectly reconstructed α-quartz surface are consistent with other dispersion-corrected DFT methods. Corrected for ZPVE, the vdW-DF/CC enthalpies of adsorption in pure-silica zeolite LTA (ΔHads(0 K)) of 3.6 and 5.2 kcal/mol for methane and carbon dioxide, respectively, are in excellent agreement with experimental values of 3.6 and 5.0 kcal/mol. The very high accuracy of the new scheme and its relatively easy use and numerical stability as compared to the earlier DFT/CC scheme offer a straightforward solution for obtaining reliable predictions of adsorption energies.

  6. MADS-Box Transcription Factor VdMcm1 Regulates Conidiation, Microsclerotia Formation, Pathogenicity, and Secondary Metabolism of Verticillium dahliae.

    PubMed

    Xiong, Dianguang; Wang, Yonglin; Tian, Longyan; Tian, Chengming

    2016-01-01

    Verticillium dahliae, a notorious phytopathogenic fungus, causes vascular wilt diseases in many plant species resulting in devastating yield losses worldwide. Due to its ability to colonize plant xylem and form microsclerotia, V. dahliae is highly persistent and difficult to control. In this study, we show that the MADS-box transcription factor VdMcm1 is a key regulator of conidiation, microsclerotia formation, virulence, and secondary metabolism of V. dahliae. In addition, our findings suggest that VdMcm1 is involved in cell wall integrity. Finally, comparative RNA-Seq analysis reveals 823 significantly downregulated genes in the VdMcm1 deletion mutant, with diverse biological functions in transcriptional regulation, plant infection, cell adhesion, secondary metabolism, transmembrane transport activity, and cell secretion. When taken together, these data suggest that VdMcm1 performs pleiotropic functions in V. dahliae. PMID:27536281

  7. MADS-Box Transcription Factor VdMcm1 Regulates Conidiation, Microsclerotia Formation, Pathogenicity, and Secondary Metabolism of Verticillium dahliae

    PubMed Central

    Xiong, Dianguang; Wang, Yonglin; Tian, Longyan; Tian, Chengming

    2016-01-01

    Verticillium dahliae, a notorious phytopathogenic fungus, causes vascular wilt diseases in many plant species resulting in devastating yield losses worldwide. Due to its ability to colonize plant xylem and form microsclerotia, V. dahliae is highly persistent and difficult to control. In this study, we show that the MADS-box transcription factor VdMcm1 is a key regulator of conidiation, microsclerotia formation, virulence, and secondary metabolism of V. dahliae. In addition, our findings suggest that VdMcm1 is involved in cell wall integrity. Finally, comparative RNA-Seq analysis reveals 823 significantly downregulated genes in the VdMcm1 deletion mutant, with diverse biological functions in transcriptional regulation, plant infection, cell adhesion, secondary metabolism, transmembrane transport activity, and cell secretion. When taken together, these data suggest that VdMcm1 performs pleiotropic functions in V. dahliae. PMID:27536281

  8. A long-period Cepheid variable in the starburst cluster VdBH222

    NASA Astrophysics Data System (ADS)

    Clark, J. S.; Negueruela, I.; Lohr, M. E.; Dorda, R.; González-Fernández, C.; Lewis, F.; Roche, P.

    2015-12-01

    Context. Galactic starburst clusters play a twin role in astrophysics, serving as laboratories for the study of stellar physics and also delineating the structure and recent star formation history of the Milky Way. Aims: In order to exploit these opportunities we have undertaken a spectroscopic survey of the red supergiant dominated young massive clusters thought to be present at both near and far ends of the Galactic Bar. Methods: Specifically, multi-epoch observations were employed to identify and investigate stellar variability and its potential role in initiating mass loss amongst the cool super-/hypergiant populations of these aggregates. Results: Significant spectroscopic variability suggestive of radial pulsations was found for the yellow supergiant VdBH 222 #505. Follow-up photometric investigations revealed modulation with a period of ~23.325 d; both timescale and pulsational profile are consistent with a Cepheid classification. Conclusions: #505 is one of the longest period Galactic cluster Cepheids identified to date and hence of considerable use in constraining the bright end of the period/luminosity relation at solar metallicities. In conjunction with extant photometry we infer a distance of ~6 kpc for VdBH222 and an age of ~20 Myr. This results in a moderate reduction in both the integrated cluster mass (~2×104M⊙) and the initial masses of the evolved cluster members (~10 M⊙). As such VdBH222 becomes an excellent test-bed for studying the properties of some of the lowest mass stars observed to undergo type-II supernovae. Moreover, the distance is in tension with a location of VdBH 222 at the far end of the Galactic Bar. Instead a birthsite in the near 3 kpc arm is suggested; providing compelling evidence of extensive recent star formation in a region of the inner Milky Way which has hitherto been thought to be devoid of such activity. Based on observations made at the European Southern Observatory, Paranal, Chile under programs ESO 093.D-0168.

  9. Bioavailability, rheology and sensory evaluation of fat-free yogurt enriched with VD3 encapsulated in re-assembled casein micelles.

    PubMed

    Levinson, Yonatan; Ish-Shalom, Sophia; Segal, Elena; Livney, Yoav D

    2016-03-01

    Vitamin D3 (VD3) deficiency is a global problem. Better ways are needed to enrich foods with this important nutraceutical. VD3 is fat-soluble, hence requiring a suitable vehicle for enriching nonfat foods. Our objectives were to assess the bioavailability of VD3, from fat-free yogurt, in re-assembled casein micelles (rCMs) compared to that in polysorbate-80 (PS80/Tween-80) a commonly used synthetic emulsifier, and to assess and compare their rheology and palatability. We enriched fat-free yogurt with VD3 loaded into either rCM (VD3-rCMs) or PS80 (VD3-PS80). In vivo VD3 bioavailability was evaluated by a large randomized, double blind, placebo-controlled clinical trial, measuring serum 25(OH)D increase in subjects who consumed fat-free yogurt with 50,000 IU of either VD3-rCM, VD3-PS80, or VD3-free placebo yogurt. Both VD3-rCM and VD3-PS80 increased the serum 25(OH)D levels by ∼8 ng ml(-1) and no significant differences in mean 25(OH)D levels were observed, evidencing the fact that VD3 bioavailability in rCM was as high as that in the synthetic emulsifier. VD3-rCM yogurt had a higher viscosity than VD3-PS80 yogurt. In sensory evaluations, panelists were able to discern between VD3-rCM and VD3-PS80 yogurt, and showed a dislike for PS80 yogurt, compared to rCM or the unenriched control. These results complement our past results showing higher protection against thermal treatment, UV irradiation, and deterioration during shelf life, conferred to hydrophobic nutraceuticals by rCM compared to that by the synthetic surfactant or to the unprotected bioactive, in showing the advantageous use of rCM over the synthetic emulsifier as a delivery system for the enrichment of food with VD3 and other hydrophobic nutraceuticals.

  10. Bioavailability, rheology and sensory evaluation of fat-free yogurt enriched with VD3 encapsulated in re-assembled casein micelles.

    PubMed

    Levinson, Yonatan; Ish-Shalom, Sophia; Segal, Elena; Livney, Yoav D

    2016-03-01

    Vitamin D3 (VD3) deficiency is a global problem. Better ways are needed to enrich foods with this important nutraceutical. VD3 is fat-soluble, hence requiring a suitable vehicle for enriching nonfat foods. Our objectives were to assess the bioavailability of VD3, from fat-free yogurt, in re-assembled casein micelles (rCMs) compared to that in polysorbate-80 (PS80/Tween-80) a commonly used synthetic emulsifier, and to assess and compare their rheology and palatability. We enriched fat-free yogurt with VD3 loaded into either rCM (VD3-rCMs) or PS80 (VD3-PS80). In vivo VD3 bioavailability was evaluated by a large randomized, double blind, placebo-controlled clinical trial, measuring serum 25(OH)D increase in subjects who consumed fat-free yogurt with 50,000 IU of either VD3-rCM, VD3-PS80, or VD3-free placebo yogurt. Both VD3-rCM and VD3-PS80 increased the serum 25(OH)D levels by ∼8 ng ml(-1) and no significant differences in mean 25(OH)D levels were observed, evidencing the fact that VD3 bioavailability in rCM was as high as that in the synthetic emulsifier. VD3-rCM yogurt had a higher viscosity than VD3-PS80 yogurt. In sensory evaluations, panelists were able to discern between VD3-rCM and VD3-PS80 yogurt, and showed a dislike for PS80 yogurt, compared to rCM or the unenriched control. These results complement our past results showing higher protection against thermal treatment, UV irradiation, and deterioration during shelf life, conferred to hydrophobic nutraceuticals by rCM compared to that by the synthetic surfactant or to the unprotected bioactive, in showing the advantageous use of rCM over the synthetic emulsifier as a delivery system for the enrichment of food with VD3 and other hydrophobic nutraceuticals. PMID:26878710

  11. van der Waals Density Functional Theory vdW-DFq for Semihard Materials

    NASA Astrophysics Data System (ADS)

    Peng, Qing; de, Suvranu

    There are a large number of materials with mild stiffness, which are not as soft as tissues and not as strong as metals. These semihard materials includes energetic materials, molecular crystals, layered materials, and van der Waals crystals. The integrity and mechanical stability are mainly determined by the interactions between instantaneously induced dipoles, the so called London dispersion force or van der Waals force. It is challenging to accurately model the structural and mechanical properties of these semihard materials in the frame of density functional theory where the non-local correlation functionals are not well known. Here we propose a van der Waals density functional named vdW-DFq to accurately model the density and geometry of semihard materials. Using β-cyclotetramethylene tetranitramine as a prototype, we adjust the enhancement factor of the exchange energy functional with generalized gradient approximations. We find this method to be simple and robust over a wide tuning range when calibrating the functional on-demand with experimental data. With a calibrated value q = 1 . 05 , the proposed vdW-DFq method shows good performance in predicting the geometries of 11 common energetic material molecular crystals and 3 typical layered van der Waals crystals. The authors would like to acknowledge the generous financial support from the Defense Threat Reduction Agency (DTRA) Grant # HDTRA1-13-1-0025.

  12. Within-population diversity of koala Chlamydophila pecorum at ompA VD1-VD3 and the ORF663 hypothetical gene.

    PubMed

    Higgins, D P; Beninati, T; Meek, M; Irish, J; Griffith, J E

    2012-05-01

    Infection of koalas by Chlamydophila pecorum is very common and causes significant morbidity, infertility and mortality. Fundamental to management of the disease is an understanding of the importance of multi-serotype infection or pathogen virulence in pathogenesis; these may need consideration in plans involving koala movement, vaccination, or disease risk assessment. Here we describe diversity of ompA VD1-3, and ORF663 hypothetical gene tandem repeat regions, in a single population of koalas with diverse disease outcomes. We PCR amplified and sequenced 72 partial ompA segments and amplified 25 tandem repeat segments (ORF663 hypothetical gene) from C. pecorum obtained from 62 koalas. Although several ompA genotypes were identified nationally, only one ompA genotype existed within the population studied, indicating that severe chlamydial disease occurs commonly in free-ranging koalas in the absence of infection by multiple MOMP serotypes of C. pecorum. In contrast, variation in tandem repeats within the ORF663 hypothetical gene was very high, approaching the entire range reported for pathogenic and non-pathogenic C. pecorum of European ruminants; providing an impetus for further investigation of this as a potential virulence trait.

  13. Potentiation of VD-induced monocytic leukemia cell differentiation by retinoids involves both RAR and RXR signaling pathways.

    PubMed

    Defacque, H; Sévilla, C; Piquemal, D; Rochette-Egly, C; Marti, J; Commes, T

    1997-02-01

    Retinoids and vitamin D (VD) cooperate to induce the differentiation and inhibit the proliferation of human myelomonocytic leukemia cells. Two classes of retinoids receptors, the RARs and RXRs, respectively, can mediate these effects. RXR forms heterodimers with a variety of nuclear receptors, including RAR and the VD receptor. We have previously found that VD treatment increases RXR alpha levels in myelomonocytic leukemia cells. By immunoanalysis, we observed in the present work that the RAR alpha protein is expressed in proliferating U937, HL-60 and THP-1 human leukemia cells and that VD treatment induces alterations of its electrophoretic pattern, although with large differences between cell lines. In the three cell lines, 9-cis RA, an agonist of both RARs and RXRs, cooperated with VD more efficiently than all-trans RA and RAR-specific synthetic ligands, thus suggesting an involvement of both RAR and RXR pathways in cell differentiation. Using U937 cells as a model, we delineated the relative contributions of RAR and RXR by assessing the effects of receptor-selective synthetic retinoids. The synergy between VD and all-trans RA or RAR-specific agonists (TTNPB and Ro 40-6055) was abrogated by a RAR alpha-specific antagonist (Ro 41-5253), confirming an involvement of RAR alpha. However, the cooperation between VD and 9-cis RA, although reduced, was not suppressed by the antagonist, suggesting also an involvement of the RXR pathway. The role of RXR as a ligand-activated receptor was confirmed using RXR-specific agonists (CD2608 and LGD1069), which also proved able to cooperate with VD. Finally, while each synthetic agonist alone was significantly less potent than 9-cis RA, combinations of the RAR and RXR selective agonists TTNPB and LGD1069 appeared to be as effective as the pan agonist 9-cis-RA. These results confirm that various retinoids can cooperate with VD and demonstrate that, at a whole cell level, optimal effects require the activation of both RAR and RXR

  14. van der Waals forces in density functional theory: a review of the vdW-DF method.

    PubMed

    Berland, Kristian; Cooper, Valentino R; Lee, Kyuho; Schröder, Elsebeth; Thonhauser, T; Hyldgaard, Per; Lundqvist, Bengt I

    2015-06-01

    A density functional theory (DFT) that accounts for van der Waals (vdW) interactions in condensed matter, materials physics, chemistry, and biology is reviewed. The insights that led to the construction of the Rutgers-Chalmers van der Waals density functional (vdW-DF) are presented with the aim of giving a historical perspective, while also emphasizing more recent efforts which have sought to improve its accuracy. In addition to technical details, we discuss a range of recent applications that illustrate the necessity of including dispersion interactions in DFT. This review highlights the value of the vdW-DF method as a general-purpose method, not only for dispersion bound systems, but also in densely packed systems where these types of interactions are traditionally thought to be negligible.

  15. van der Waals forces in density functional theory: a review of the vdW-DF method

    DOE PAGES

    Berland, Kristian; Cooper, Valentino R.; Lee, Kyuho; Schröder, Elsebeth; Thonhauser, T.; Hyldgaard, Per; Lundqvist, Bengt I.

    2015-05-15

    We review a density functional theory (DFT) that accounts for van der Waals (vdW) interactions in condensed matter, materials physics, chemistry, and biology. The insights that led to the construction of the Rutgers–Chalmers van der Waals density functional (vdW-DF) are presented with the aim of giving a historical perspective, while also emphasizing more recent efforts which have sought to improve its accuracy. In addition to technical details, we discuss a range of recent applications that illustrate the necessity of including dispersion interactions in DFT. This review highlights the value of the vdW-DF method as a general-purpose method, not only formore » dispersion bound systems, but also in densely packed systems where these types of interactions are traditionally thought to be negligible.« less

  16. van der Waals forces in density functional theory: a review of the vdW-DF method

    SciTech Connect

    Berland, Kristian; Cooper, Valentino R.; Lee, Kyuho; Schröder, Elsebeth; Thonhauser, T.; Hyldgaard, Per; Lundqvist, Bengt I.

    2015-05-15

    We review a density functional theory (DFT) that accounts for van der Waals (vdW) interactions in condensed matter, materials physics, chemistry, and biology. The insights that led to the construction of the Rutgers–Chalmers van der Waals density functional (vdW-DF) are presented with the aim of giving a historical perspective, while also emphasizing more recent efforts which have sought to improve its accuracy. In addition to technical details, we discuss a range of recent applications that illustrate the necessity of including dispersion interactions in DFT. This review highlights the value of the vdW-DF method as a general-purpose method, not only for dispersion bound systems, but also in densely packed systems where these types of interactions are traditionally thought to be negligible.

  17. Comparison of thirty-seven strains of Vd-3 bacteria with Agrobacterium radiobacter: morphological and physiological observations.

    PubMed

    Riley, P S; Weaver, R E

    1977-02-01

    Thirty-seven cultures of Vd-3 bacteria, isolated from clinical specimens, were characterized morphologically and physiologically. The cultures produced positive reactions when tested for oxidase, urease, nitrate reduction, phenylalanine deaminase, oxidative metabolism of carbohydrate substrates, and 3-ketolactose production. These peritrichously flagellated microorganisms were isolated primarily from the respiratory tract. When compared to authentic strains of Agrobacterium, they appeared to be most similar to A. radiobacter. Gas-liquid chromatography of trimethylsilyl derivatives of whole-cell hydrolysates of some of the Vd-3 strains and A. radiobacter yielded nearly identical elution patterns. The Vd-3 cultures were identified as probable strains of A. radiobacter. A method is presented for differentiating cultures of A. radiobacter from other similar bacteria encountered in clinical specimens. Although these bacteria rarely occur in clinical specimens, the clinical microbiologist should be familiar withe their outstanding characteristics.

  18. VdBH 222: a starburst cluster in the inner Milky Way⋆

    NASA Astrophysics Data System (ADS)

    Marco, A.; Negueruela, I.; González-Fernández, C.; Maíz Apellániz, J.; Dorda, R.; Clark, J. S.

    2014-07-01

    Context. It has been suggested that the compact open cluster VdBH 222 is a young massive distant object. Aims: We set out to characterise VdBH 222 using a comprehensive set of multi-wavelength observations. Methods: We obtained multi-band optical (UBVR) and near-infrared (JHKS) photometry of the cluster field, as well as multi-object and long-slit optical spectroscopy for a large sample of stars in the field. We applied classical photometric analysis, as well as more sophisticated methods using the CHORIZOS code, to determine the reddening to the cluster. We then plotted dereddened HR diagrams and determined cluster parameters via isochrone fitting. Results: We have identified a large population of luminous supergiants confirmed as cluster members via radial velocity measurements. We find nine red supergiants (plus one other candidate) and two yellow supergiants. We also identify a large population of OB stars. Ten of them are bright enough to be blue supergiants. The cluster lies behind ≈7.5 mag of extinction for the preferred value of RV = 2.9. Isochrone fitting allows for a narrow range of ages between 12 and 16 Ma. The cluster radial velocity is compatible with distances of ~6 and ~10 kpc. The shorter distance is inconsistent with the age range and Galactic structure. The longer distance implies an age ≈ 12 Ma and a location not far from the position where some Galactic models place the far end of the Galactic bar. Conclusions: VdBH 222 is a young massive cluster with a likely mass >20 000 M⊙. Its population of massive evolved stars is comparable to that of large associations, such as Per OB1. Its location in the inner Galaxy, presumably close to the end of the Galactic bar, adds to the increasing evidence for vigorous star formation in the inner regions of the Milky Way. Partially based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile (ESO 089.D-0332, ESO 081.D-0812) and the Australian

  19. Effects of neuropeptide FF and related peptides on the antinociceptive activities of VD-hemopressin(α) in naive and cannabinoid-tolerant mice.

    PubMed

    Pan, Jia-Xin; Wang, Zi-Long; Li, Ning; Zhang, Nan; Wang, Pei; Tang, Hong-Hai; Zhang, Ting; Yu, Hong-Ping; Zhang, Run; Zheng, Ting; Fang, Quan; Wang, Rui

    2015-11-15

    Neuropeptide FF (NPFF) system has recently been reported to modulate cannabinoid-induced antinociception. The aim of the present study was to further investigate the roles of NPFF system in the antinociceptive effects induced by intracerebroventricular (i.c.v.) administration of mouse VD-hemopressin(α), a novel endogenous agonist of cannabinoid CB1 receptor, in naive and VD-hemopressin(α)-tolerant mice. The effects of NPFF system on the antinociception induced by VD-hemopressin(α) were investigated in the radiant heat tail-flick test in naive mice and VD-hemopressin(α)-tolerant mice. The cannabinoid-tolerant mice were produced by given daily injections of VD-hemopressin(α) (20 nmol, i.c.v.) for 5 days and the antinociception was measured on day 6. In naive mice, intracerebroventricular injection of NPFF dose-dependently attenuated central analgesia of VD-hemopressin(α). In contrast, neuropeptide VF (NPVF) and D.NP(N-Me)AFLFQPQRF-NH2 (dNPA), two highly selective agonists for Neuropeptide FF1 and Neuropeptide FF2 receptors, enhanced VD-hemopressin(α)-induced antinociception in a dose-dependent manner. In addition, the VD-hemopressin(α)-modulating activities of NPFF and related peptides were antagonized by the Neuropeptide FF receptors selective antagonist 1-adamantanecarbonyl-RF-NH2 (RF9). In VD-hemopressin(α)-tolerant mice, NPFF failed to modify VD-hemopressin(α)-induced antinociception. However, both neuropeptide VF and dNPA dose-dependently potentiated the antinociception of VD-hemopressin(α) and these cannabinoid-potentiating effects were reduced by RF9. The present works support the cannabinoid-modulating character of NPFF system in naive and cannabinoid-tolerant mice. In addition, the data suggest that a chronic cannabinoid treatment modifies the pharmacological profiles of NPFF, but not the cannabinoid-potentiating effects of neuropeptide VF and dNPA.

  20. ThP05 Biogeneration of Volatile Selenium Compounds in Biosolids/Biofuels and Quantification by VD/GC/ICPMS

    EPA Science Inventory

    A noval analytical approach that uses VD/GC/ICPMS for the on-line extraction and quantificationof volatile organopmetalloids is described. Several species of arsenic, selenium, antimony, bismuth and tellurium are amenable to this technique. Preliminary results of a study on the...

  1. Graphene-based vdW heterostructure Induced High-efficiency Thermoelectric Devices

    NASA Astrophysics Data System (ADS)

    Liang, Shijun; Ang, Lay Kee

    Thermoelectric material (TE) can convert the heat into electricity to provide green energy source and its performance is characterized by a figure of merit (ZT) parameter. Traditional TE materials only give ZT equal to around 1 at room temperature. But, it is believed that materials with ZT >3 will find wide applications at this low temperature range. Prior studies have implied that the interrelation between electric conductivity and lattice thermal conductivity renders the goal of engineering ZT of bulk materials to reach ZT >3. In this work, we propose a high-efficiency van del Waals (vdW) heterostructure-based thermionic device with graphene electrodes, which is able to harvest wasted heat (around 400K) based on the newly established thermionic emission law of graphene electrodes instead of Seebeck effect, to boost the efficiency of power generation over 10% around room temperature. The efficiency can be above 20% if the Schottky barrier height and cross-plane lattice thermal conductivity of transition metal dichacogenides (TMD) materials can be fine-engineered. As a refrigerator at 260 K, the efficiency is 50% to 80% of Carnot efficiency. Finally, we identify two TMD materials as the ideal candidates of graphene/TMD/graphene devices based on the state-of-art technology.

  2. VdTX-1, a reversible nicotinic receptor antagonist isolated from venom of the spider Vitalius dubius (Theraphosidae).

    PubMed

    Rocha-E-Silva, Thomaz A A; Rostelato-Ferreira, Sandro; Leite, Gildo B; da Silva, Pedro Ismael; Hyslop, Stephen; Rodrigues-Simioni, Léa

    2013-08-01

    Theraphosid spider venoms can block neurotransmission in vertebrate nerve-muscle preparations in vitro, but few of the components involved have been characterized. In this work, we describe the neuromuscular activity of venom from the Brazilian theraphosid Vitalius dubius and report the purification and pharmacological characterization of VdTX-1, a 728 Da toxin that blocks nicotinic receptors. Neuromuscular activity was assayed in chick biventer cervicis preparations and muscle responses to exogenous ACh and KCl were determined before and after incubation with venom or toxin. Changes in membrane resting potential were studied in mouse diaphragm muscle. The toxin was purified by a combination of filtration through Amicon® filters, cation exchange HPLC and RP-HPLC; toxin purity and mass were confirmed by mass spectrometry. Venom caused progressive neuromuscular blockade and muscle contracture; the blockade but not the contracture was reversible by washing. Venom attenuated contractures to exogenous ACh and KCl. Filtration yielded low (LM, <5 kDa) and high (HM, >5 kDa) fractions, with the latter reproducing the contracture seen in venom but with a slight and progressive twitch blockade. The LM fraction caused reversible blockade and attenuated contractures to ACh, but had no effect on contractures to KCl. VdTX-1 (728 Da) purified from the LM fraction was photosensitive and reduced the E(max) to ACh in biventer cervicis muscle without affecting the EC₅₀; VdTX-1 also abolished carbachol-induced depolarizations. V. dubius venom contains at least two components that affect vertebrate neurotransmission. One component, VdTX-1, blocks nicotinic receptors non-competitively to produce reversible blockade without muscle contracture.

  3. Field evaluations of the VD max approach for substantiation of a 25 kGy sterilization dose and its application to other preselected doses

    NASA Astrophysics Data System (ADS)

    Kowalski, John B.; Herring, Craig; Baryschpolec, Lisa; Reger, John; Patel, Jay; Feeney, Mary; Tallentire, Alan

    2002-08-01

    The International and European standards for radiation sterilization require evidence of the effectiveness of a minimum sterilization dose of 25 kGy but do not provide detailed guidance on how this evidence can be generated. An approach, designated VD max, has recently been described and computer evaluated to provide safe and unambiguous substantiation of a 25 kGy sterilization dose. The approach has been further developed into a practical method, which has been subjected to field evaluations at three manufacturing facilities which produce different types of medical devices. The three facilities each used a different overall evaluation strategy: Facility A used VD max for quarterly dose audits; Facility B compared VD max and Method 1 in side-by-side parallel experiments; and Facility C, a new facility at start-up, used VD max for initial substantiation of 25 kGy and subsequent quarterly dose audits. A common element at all three facilities was the use of 10 product units for irradiation in the verification dose experiment. The field evaluations of the VD max method were successful at all three facilities; they included many different types of medical devices/product families with a wide range of average bioburden and sample item portion values used in the verification dose experiments. Overall, around 500 verification dose experiments were performed and no failures were observed. In the side-by-side parallel experiments, the outcomes of the VD max experiments were consistent with the outcomes observed with Method 1. The VD max approach has been extended to sterilization doses >25 and <25 kGy; verification doses have been derived for sterilization doses of 15, 20, 30, and 35 kGy. Widespread application of the VD max method for doses other than 25 kGy must await controlled field evaluations and the development of appropriate specifications/standards.

  4. VdCYC8, Encoding CYC8 Glucose Repression Mediator Protein, Is Required for Microsclerotia Formation and Full Virulence in Verticillium dahliae.

    PubMed

    Li, Zhi-Fang; Liu, Yi-Jie; Feng, Zi-Li; Feng, Hong-Jie; Klosterman, Steven J; Zhou, Fang-Fang; Zhao, Li-Hong; Shi, Yong-Qiang; Zhu, He-Qin

    2015-01-01

    Verticillium dahliae is the primary causal agent for Verticillium wilt disease on a diverse array of economically important crops, including cotton. In previous research, we obtained the low-pathogenicity mutant T286 from the T-DNA insertional mutant library of the highly virulent isolate Vd080 derived from cotton. In this study, the target disrupted gene VdCYC8 was identified by TAIL-PCR, encoding a homolog of CYC8 proteins involved in glucose repression. The deletion mutant ΔCYC8 exhibited several developmental deficiencies, including reduced microsclerotia formation, reduced sporulation, and slower growth. Moreover, compared with the wild type strain Vd080, the pathogenicity of strain ΔCYC8 was significantly decreased on cotton seedlings. However, the complementary mutants ΔCYC8-C led to restoration of the wild type phenotype or near wild type levels of virulence on cotton. Interestingly, pathogenicity of the strains was correlated with VdCYC8 gene expression levels in complemented mutants. Gene expression analyses in the wild type strain Vd080, the ΔCYC8-45 strain, and complemented strain ΔCYC8-C26 indicated that VdCYC8 regulates the transcription levels of several genes in V. dahliae that have roles in melanin and production.

  5. VdCYC8, Encoding CYC8 Glucose Repression Mediator Protein, Is Required for Microsclerotia Formation and Full Virulence in Verticillium dahliae

    PubMed Central

    Li, Zhi-Fang; Liu, Yi-Jie; Feng, Zi-Li; Feng, Hong-Jie; Klosterman, Steven J.; Zhou, Fang-Fang; Zhao, Li-Hong; Shi, Yong-Qiang; Zhu, He-Qin

    2015-01-01

    Verticillium dahliae is the primary causal agent for Verticillium wilt disease on a diverse array of economically important crops, including cotton. In previous research, we obtained the low-pathogenicity mutant T286 from the T-DNA insertional mutant library of the highly virulent isolate Vd080 derived from cotton. In this study, the target disrupted gene VdCYC8 was identified by TAIL-PCR, encoding a homolog of CYC8 proteins involved in glucose repression. The deletion mutant ΔCYC8 exhibited several developmental deficiencies, including reduced microsclerotia formation, reduced sporulation, and slower growth. Moreover, compared with the wild type strain Vd080, the pathogenicity of strain ΔCYC8 was significantly decreased on cotton seedlings. However, the complementary mutants ΔCYC8-C led to restoration of the wild type phenotype or near wild type levels of virulence on cotton. Interestingly, pathogenicity of the strains was correlated with VdCYC8 gene expression levels in complemented mutants. Gene expression analyses in the wild type strain Vd080, the ΔCYC8-45 strain, and complemented strain ΔCYC8-C26 indicated that VdCYC8 regulates the transcription levels of several genes in V. dahliae that have roles in melanin and production. PMID:26633180

  6. [Preliminary study of the safety and immunogenicity of the attenuated VD47/25 strain of camelpoxvirus].

    PubMed

    Nguyen-Ba-Vy; Guerre, L; Saint-Martin, G

    1996-01-01

    The safety and immunogenicity of the attenuated VD47/25 strain of camelpoxvirus were tested on 30 camel calves in Mauritania. Post-inoculation clinical symptoms were absent during the 40 days of observation. Serum samples collected during this period showed low levels of neutralizing antibodies (1/4-1/16). In vivo titration of a virulent strain of camelpoxvirus in vaccinated camels and control animals enabled the calculation of the PD50 (50% protective dose) which contained the equivalent of 10(3.7) TCID50 (50% cell culture infective dose). Other studies are still required to determine the dose of this vaccine needed to protect 95% of vaccinated animals.

  7. Mechanical Properties of a vdW molecular monolayer at a metal surface: Structural Polymorphism leading to facile compression

    NASA Astrophysics Data System (ADS)

    Sun, Dezheng; Kim, Daeho; Le, Duy; Borck, Øyvind; Berland, Kristian; Kim, Kwangmoo; Lu, Wenhao; Zhu, Yeming; Luo, Miaomiao; Wyrick, Jon; Cheng, Zhihai; Einstein, T. L.; Rahman, Talat; Hyldgaard, Per; Bartels, Ludwig

    2011-03-01

    Intermolecular force plays an important role in self-assembly and surface pattern formation. Anthracene and similar unsubstituted arenes attach to a metallic substrate predominantly through van der Waals interaction leading. In this contribution we present images how anthracene on Cu(111) forms a large number of highly ordered patterns that feature a broad array of structural motifs. Density functional theory modeling including vdW interactions allows us to model the energetic of the pattern formation at high fidelity. Moreover, it allows us to deduce the strain energy associated with films of varying coverage. From this work, we obtain the Young's modulus and Poisson Ratio of a molecular monolayer, which resemble properties conventionally found for porous materials. These patterns are in marked contrast to those found after introduction of functional groups in the molecules, such as carbonyls or thiols.

  8. Lightcurve Photometry of NEAs 4450 Pan, (170891) 2004 TY16 2002 RC118, and 2007 VD12

    NASA Astrophysics Data System (ADS)

    Carbognani, Alberto

    2008-09-01

    Lightcurve periods and amplitudes are reported for Amor asteroid (170891) 2004 TY16 (P = 2.795 ± 0.002 h; A = 0.2 ± 0.02 mag), Amor asteroid 2002 RC118 (P = 9.98 ± 0.02 h; A = 0.4 ± 0.03 mag), and Apollo PHA 2007 VD12 (P = 7.418 ± 0.005 h; A = 0.6 ± 0.05 mag). For 4450 Pan it was not possible to establish a period, but we were able to determine color indices, absolute magnitude, and diameter. A search for a cometary activity of 2002 RC118 was made with negative results.

  9. VizieR Online Data Catalog: Photometry of VdBH 222 stars and field stars (Marco+, 2014)

    NASA Astrophysics Data System (ADS)

    Marco, A.; Negueruela, I.; Gonzalez-Fernandez, C.; Maiz Apellaniz, J.; Dorda, R.; Clark, J. S.

    2014-05-01

    We obtained UBVR photometry of VdBH 222 using the ESO Faint Object Spectrograph and Camera (EFOSC2) on the NTT on the night of 24 June 2012. The instrument was equipped with CCD#40, which is a Loral/Lesser, thinned, AR-coated, UV-flooded, and MPP chip that is controlled by ESO-FIERA. It covers a field of view of and 4.1'x4.1' and has a pixel scale of 0.12". The JHK images were obtained using the Son OF Isaac (SOFI) near-IR spectrograph and camera on the NTT on 13 July 2008, equipped with a CCD providing a pixel scale of 0.288arcsec and an field of view of 4.92x4.95' (4 data files).

  10. The role of vdW interactions in coverage dependent adsorption energies of atomic adsorbates on Pt(111) and Pd(111)

    NASA Astrophysics Data System (ADS)

    Thirumalai, Hari; Kitchin, John R.

    2016-08-01

    Adsorption, a fundamental process in heterogeneous catalysis is known to be dependent on the adsorbate-adsorbate and surface-adsorbate bonds. van der Waals (vdW) interactions are one of the types of interactions that have not been examined thoroughly as a function of adsorbate coverage. In this work we quantify the vdW interactions for atomic adsorbates on late transition metal surfaces, and determine how these long range forces affect the coverage dependent adsorption energies. We calculate the adsorption energies of carbon, nitrogen, oxygen, sulfur, fluorine, bromine and chlorine species on Pt(111) and Pd(111) at coverages ranging from 1/4 to 1 ML using the BEEF-vdW functional. We observe that adsorption energies remain coverage dependent, and this coverage dependence is shown to be statistically significant. vdW interactions are found to be coverage dependent, but more significantly, they are found to be dependent on molecular properties such as adsorbate size, and consequently, correlate with the adsorbate effective nuclear charge. We observe that these interactions account for a reduction in the binding energy of the system, due to the destabilizing attractive interactions between the adsorbates which weaken its bond with the surface.

  11. VdCYC8, encoding CYC8 glucose repression mediator protein, is required for microsclerotia formation and full virulence in Verticillium dahliae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Verticillium dahliae is the primary causal agent for Verticillium wilt disease on a diverse array of economically important crops, including cotton. In previous research, we screened a T-DNA insertional mutant library of the highly virulent isolate Vd080 derived from cotton. In this study, the targ...

  12. [Dynamics of dry deposition velocities (Vd) of atmospheric SO2 on rapeseed/rice rotation systems in selected area of south China].

    PubMed

    Hu, Zhengyi; Xu, Chengkai; Cao, Zhihong; Wang, Tijian; Zhao, Yanwen

    2003-09-01

    With the profile meteorological data collected from the farmland micro-meteorological experimental substation, Experiment Station of Red Earth Ecology, Yingtan, Jiangxi, Chinese Academy of Sciences during rapeseed/rice rotation from Nov. 1998 to Oct. 1999, the surface layer turbulence characteristic parameters (u*, theta*, L) and the atmospheric SO2 dry deposition velocities (Vd) were calculated. The results indicated that the hourly mean Vd of SO2 dry deposition was ranged from 0.124 to 0.897 cm.s-1 (mean +/- SE = 0.507 +/- 0.167 cm.s-1), and its regular dynamic pattern was as follows: it was always higher at daytime than at night, and the mean Vd of SO2 dry deposition during March-August(0.611 cm.s-1) was obviously greater than that during Sept.-Dec. and Jan.-Feb. (0.401 cm.s-1). The mean Vd of SO2 dry deposition during various crop growth stages was decreased as the order of rice (0.605 +/- 0.093 cm.s-1) > rapeseed (0.491 +/- 0.166 cm.s-1) > follow (0.342 +/- 0.174 cm.s-1).

  13. A cupin domain-containing protein with a quercetinase activity (VdQase) regulates Verticillium dahliae's pathogenicity and contributes to counteracting host defenses

    PubMed Central

    El Hadrami, Abdelbasset; Islam, Md. Rashidul; Adam, Lorne R.; Daayf, Fouad

    2015-01-01

    We previously identified rutin as part of potato root responses to its pathogen Verticillium dahliae. Rutin was directly toxic to the pathogen at doses greater than 160 μM, a threshold below which many V. dahliae pathogenicity-related genes were up-regulated. We identified and characterized a cupin domain-containing protein (VdQase) with a dioxygenase activity and a potential role in V. dahliae-potato interactions. The pathogenicity of VdQase knock-out mutants generated through Agrobacterium tumefasciens-mediated transformation was significantly reduced on susceptible potato cultivar Kennebec compared to wild type isolates. Fluorescence microscopy revealed a higher accumulation of flavonols in the stems of infected potatoes and a higher concentration of rutin in the leaves in response to the VdQase mutants as compared to wild type isolates. This, along with the HPLC characterization of high residual and non-utilized quercetin in presence of the knockout mutants, indicates the involvement of VdQase in the catabolism of quercetin and possibly other flavonols in planta. Quantification of Salicylic and Jasmonic Acids (SA, JA) in response to the mutants vs. wild type isolates revealed involvement of VdQase in the interference with signaling, suggesting a role in pathogenicity. It is hypothesized that the by-product of dioxygenation 2-protocatechuoylphloroglucinolcarboxylic acid, after dissociating into phloroglucinol and protocatechuoyl moieties, becomes a starting point for benzoic acid and SA, thereby interfering with the JA pathway and affecting the interaction outcome. These events may be key factors for V. dahliae in countering potato defenses and becoming notorious in the rhizosphere. PMID:26113857

  14. Hydrogen Sulfide Prevents Synaptic Plasticity from VD-Induced Damage via Akt/GSK-3β Pathway and Notch Signaling Pathway in Rats.

    PubMed

    Liu, Chunhua; Xu, Xiaxia; Gao, Jing; Zhang, Tao; Yang, Zhuo

    2016-08-01

    Our previous study has demonstrated that hydrogen sulfide (H2S) attenuates neuronal injury induced by vascular dementia (VD) in rats, but the mechanism is still poorly understood. In this study, we aimed to investigate whether the neuroprotection of H2S was associated with synaptic plasticity and try to interpret the potential underlying mechanisms. Adult male Wistar rats were suffered the ligation of bilateral common carotid arteries. At 24 h after surgery, rats were administered intraperitoneally with sodium hydrosulfide (NaHS, 5.6 mg·kg(-1)·day(-1)), a H2S donor, for 3 weeks in the VD+NaHS group and treated intraperitoneally with saline in the VD group respectively. Our results demonstrated that NaHS significantly decreased the level of glutamate. It obviously ameliorated cognitive flexibility as well as the spatial learning and memory abilities by Morris water maze. Moreover, NaHS significantly improved the long-term depression (LTD), and was able to elevate the expression of N-methyl-D-aspartate receptor subunit 2A, which plays a pivotal role in synaptic plasticity. Interestingly, NaHS decreased the phosphorylation of Akt, and it could maintain the activity of glycogen synthase kinase-3β (GSK-3β). Surprisingly, NaHS triggered the canonical Notch pathway by increasing expressions of Jagged-1 and Hes-1. These findings suggest that NaHS prevents synaptic plasticity from VD-induced damage partly via Akt/GSK-3β pathway and Notch signaling pathway.Hydrogen sulfide modulated the ratio of NMDAR 2A/2B and improved the synaptic plasticity via Akt/GSK-3β pathway and Notch signaling pathway in VD rats.

  15. [Down-regulation of p38 MAPK and collagen by 1, 25-(OH)2-VD3 in rat models of diabetic nephropathy].

    PubMed

    Xie, Xianhui; Li, Zhengsheng; Pi, Mingjing; Wu, Jing; Zeng, Wen; Zuo, Li; Zha, Yan

    2016-07-01

    Objective To investigate the effect of 1, 25-(OH)2-VD3 on collagen type III (Col3), collagen type IV (Col4) and p38 mitogen-activated protein kinase (p38 MAPK) in rat models of type 2 diabetic nephropathy, and explore the relationships of p38MAPK with Col3 and Col4. Methods Rat models of type 2 diabetic nephropathy were induced by streptozocin (STZ, 30 mg/kg) combined with high-glucose-and-fat diet. Sixty rats were randomly divided into control group, model group, 1, 25-(OH)2-VD3 treatment group [given 1, 25-(OH)2-VD3 6 ng/(100 g.d) after modeling] and insulin group (given 2-3 U insulin after modeling). After 8 weeks' intervention, serum creatinine (Scr), blood urea nitrogen (BUN) and 24-hour proteinuria were detected in all groups. Periodic acid-Schiff (PAS) staining was used to observe the kidney pathological changes, and immunohistochemical staining and Western blotting were performed to determine p38 MAPK Col3 and Col4 expressions in rat renal interstitium. Spearman method was applied to the correlation analysis. Results Compared with the model group, blood glucose, Scr, BUN, 24-hour proteinuria and impaired renal interstitial area were all reduced in the 1, 25-(OH)2-VD3 treatment group and the insulin group. Compared with the control group, the expressions of Col3, Col4 and p38 MAPK were higher in the model group, and lower in the 1, 25-(OH)2-VD3 treatment group and the insulin group. Correlation analysis showed that 24-hour proteinuria was positively related with p38 MAPK, Col3, Col4 and immunohistochemical results; p38MAPK was positively correlated with Col3 and Col4 expressions. Conclusion Col3, Col4 and p38MAPK are up-regulated in rat models of type 2 diabetic nephropathy. The 1, 25-(OH)2-VD3 might attenuates the progression of renal interstitial fibrosis via down-regulating p38 MAPK, Col3 and Col4. PMID:27363275

  16. Structural and ionic conductivity studies of electrospun polymer blend P(VdF-co-HFP)/PMMA electrolyte membrane for lithium battery application

    NASA Astrophysics Data System (ADS)

    Padmaraj, O.; Venkateswarlu, M.; Satyanarayana, N.

    2015-06-01

    A novel fibrous polymer blend [(100-x) % P(VdF-co-HFP)/x % PMMA, x = 10, 20, 30, 40, 50] electrolyte membranes were prepared by electrospinning technique. Structural, thermal and surface morphology of all the compositions of electrospun polymer blend membranes were studied by using XRD, DSC & SEM. The newly developed five different compositions of polymer blend fibrous electrolyte membranes were obtained by soaking in an electrolyte solution contains 1M LiPF6 in EC: DEC (1:1,v/v). The wet-ability and conductivity of all the compositions of polymer blend electrolyte membranes are evaluated through electrolyte uptake and impedance measurements. The polymer blend [90% P(VdF-co-HFP)/10% PMMA] electrolyte membrane showed good wet-ability and high conductivity (1.788 × 10-3 Scm-1) at room temperature.

  17. Structural and ionic conductivity studies of electrospun polymer blend P(VdF-co-HFP)/PMMA electrolyte membrane for lithium battery application

    SciTech Connect

    Padmaraj, O.; Satyanarayana, N.; Venkateswarlu, M.

    2015-06-24

    A novel fibrous polymer blend [(100-x) % P(VdF-co-HFP)/x % PMMA, x = 10, 20, 30, 40, 50] electrolyte membranes were prepared by electrospinning technique. Structural, thermal and surface morphology of all the compositions of electrospun polymer blend membranes were studied by using XRD, DSC & SEM. The newly developed five different compositions of polymer blend fibrous electrolyte membranes were obtained by soaking in an electrolyte solution contains 1M LiPF{sub 6} in EC: DEC (1:1,v/v). The wet-ability and conductivity of all the compositions of polymer blend electrolyte membranes are evaluated through electrolyte uptake and impedance measurements. The polymer blend [90% P(VdF-co-HFP)/10% PMMA] electrolyte membrane showed good wet-ability and high conductivity (1.788 × 10{sup −3} Scm{sup −1}) at room temperature.

  18. Star-forming regions at the periphery of the supershell surrounding the Cyg OB1 association - I. The star cluster vdB 130 and its ambient gas and dust medium

    NASA Astrophysics Data System (ADS)

    Sitnik, T. G.; Egorov, O. V.; Lozinskaya, T. A.; Moiseev, A. V.; Rastorguev, A. S.; Tatarnikov, A. M.; Tatarnikova, A. A.; Wiebe, D. S.; Zabolotskikh, M. V.

    2015-12-01

    Stellar population and the interstellar gas-dust medium in the vicinity of the open star cluster vdB 130 are analysed using optical observations taken with the 6 m telescope of the Special Astrophysical Observatory of Russian Academy of Sciences and the 125 cm telescope of the Sternberg Astronomical Institute, Lomonosov Moscow State University along with the data of Spitzer and Herschel. Based on proper motions and BV and JHKs Two Micron All Sky Survey photometric data, we select additional 36 stars as probable cluster members. Some stars in vdB 130 are classified as B stars. Our estimates of minimum colour excess, apparent distance modulus and the distance are consistent with young age (from 5 to 10 Myr) of the cluster vdB 130. We suppose the large deviations from the conventional extinction law in the cluster direction, with RV ˜ 4-5. The cluster vdB 130 appears to be physically related to the supershell around Cyg OB1, a cometary CO cloud, ionized gas and regions of infrared emission. There are a few regions of bright mid-infrared emission in the vicinity of vdB 130. The largest of them is also visible on Hα and [S II] emission maps. We suggest that the infrared blobs that coincide in projection with the head of the molecular cloud are H II regions, excited by the cluster B stars. Some signatures of a shock front are identified between these IR-bright regions.

  19. In-depth proteomic analysis of Varroa destructor: Detection of DWV-complex, ABPV, VdMLV and honeybee proteins in the mite.

    PubMed

    Erban, Tomas; Harant, Karel; Hubalek, Martin; Vitamvas, Pavel; Kamler, Martin; Poltronieri, Palmiro; Tyl, Jan; Markovic, Martin; Titera, Dalibor

    2015-09-11

    We investigated pathogens in the parasitic honeybee mite Varroa destructor using nanoLC-MS/MS (TripleTOF) and 2D-E-MS/MS proteomics approaches supplemented with affinity-chromatography to concentrate trace target proteins. Peptides were detected from the currently uncharacterized Varroa destructor Macula-like virus (VdMLV), the deformed wing virus (DWV)-complex and the acute bee paralysis virus (ABPV). Peptide alignments revealed detection of complete structural DWV-complex block VP2-VP1-VP3, VDV-1 helicase and single-amino-acid substitution A/K/Q in VP1, the ABPV structural block VP1-VP4-VP2-VP3 including uncleaved VP4/VP2, and VdMLV coat protein. Isoforms of viral structural proteins of highest abundance were localized via 2D-E. The presence of all types of capsid/coat proteins of a particular virus suggested the presence of virions in Varroa. Also, matches between the MWs of viral structural proteins on 2D-E and their theoretical MWs indicated that viruses were not digested. The absence/scarce detection of non-structural proteins compared with high-abundance structural proteins suggest that the viruses did not replicate in the mite; hence, virions accumulate in the Varroa gut via hemolymph feeding. Hemolymph feeding also resulted in the detection of a variety of honeybee proteins. The advantages of MS-based proteomics for pathogen detection, false-positive pathogen detection, virus replication, posttranslational modifications, and the presence of honeybee proteins in Varroa are discussed.

  20. The nature of the young and low-mass open clusters Pismis5, vdB80, NGC1931 and BDSB96

    NASA Astrophysics Data System (ADS)

    Bonatto, C.; Bica, E.

    2009-08-01

    We investigate the nature of four young and low-mass open clusters (OCs) located in the second and third quadrants with near-infrared Two-Micron All Sky Survey (2MASS) photometry (errors <0.1mag). After field decontamination, the colour-magnitude diagrams (CMDs) display similar morphologies: a poorly populated main sequence (MS) and a dominant fraction of pre-MS (PMS) stars somewhat affected by differential reddening. Pismis5, vdB80 and BDSB96 have MS ages within 5 +/- 4Myr, while the MS of NGC1931 is 10 +/- 3Myr old. However, non-instantaneous star formation is implied by the wider (~20Myr) PMS age spread. The cluster masses derived from MS+PMS stars are low, within ~60-180Msolar, with mass functions (MFs) significantly flatter than Salpeter's initial mass function (IMF). Distances from the Sun are within 1.0-2.4kpc, and the visual absorptions are in the range AV = 1.0-2.0. From the stellar radial density profiles (RDPs), we find that they are small (Rc <~ 0.48pc, RRDP <~ 5.8pc), especially Pismis5 with Rc ~ 0.2pc and RRDP ~ 1.8pc. Except for the irregular and cuspy inner regions of NGC1931 and Pismis5, the stellar RDPs follow a King-like profile. At ~10Myr, central cusps - which in old clusters appear to be related to advanced dynamical evolution - are probably associated with a star formation and/or molecular cloud fragmentation effect. Despite the flat MFs, vdB80 and BDSB96 appear to be typical young, low-mass OCs. NGC1931 and especially Pismis5, with irregular RDPs, low cluster mass and flat MFs, do not appear to be in dynamical equilibrium. Both may be evolving into OB associations and/or doomed to dissolution in a few 107yr.

  1. In-depth proteomic analysis of Varroa destructor: Detection of DWV-complex, ABPV, VdMLV and honeybee proteins in the mite

    PubMed Central

    Erban, Tomas; Harant, Karel; Hubalek, Martin; Vitamvas, Pavel; Kamler, Martin; Poltronieri, Palmiro; Tyl, Jan; Markovic, Martin; Titera, Dalibor

    2015-01-01

    We investigated pathogens in the parasitic honeybee mite Varroa destructor using nanoLC-MS/MS (TripleTOF) and 2D-E-MS/MS proteomics approaches supplemented with affinity-chromatography to concentrate trace target proteins. Peptides were detected from the currently uncharacterized Varroa destructor Macula-like virus (VdMLV), the deformed wing virus (DWV)-complex and the acute bee paralysis virus (ABPV). Peptide alignments revealed detection of complete structural DWV-complex block VP2-VP1-VP3, VDV-1 helicase and single-amino-acid substitution A/K/Q in VP1, the ABPV structural block VP1-VP4-VP2-VP3 including uncleaved VP4/VP2, and VdMLV coat protein. Isoforms of viral structural proteins of highest abundance were localized via 2D-E. The presence of all types of capsid/coat proteins of a particular virus suggested the presence of virions in Varroa. Also, matches between the MWs of viral structural proteins on 2D-E and their theoretical MWs indicated that viruses were not digested. The absence/scarce detection of non-structural proteins compared with high-abundance structural proteins suggest that the viruses did not replicate in the mite; hence, virions accumulate in the Varroa gut via hemolymph feeding. Hemolymph feeding also resulted in the detection of a variety of honeybee proteins. The advantages of MS-based proteomics for pathogen detection, false-positive pathogen detection, virus replication, posttranslational modifications, and the presence of honeybee proteins in Varroa are discussed. PMID:26358842

  2. NanoSrTiO3-filled PEO-P(VdF-HFP)-LiClO4 electrolytes with improved electrical and thermal properties

    NASA Astrophysics Data System (ADS)

    Jayanthi, S.; Arulsankar, A.; Sundaresan, B.

    2016-02-01

    In the present work, PEO:P(VdF-HFP) polymer blend was prepared. The blend was complexed with lithium perchlorate (LiClO4), and nanosized strontium titanate (70.60 nm) SrTiO3 particles were dispersed into the complex in different weight ratios. Acetonitrile was used as solvent. The nanocomposite polymer blend electrolytes (NCPBEs) were prepared by the solvent-casting technique. Ionic conductivity of polymer blend electrolyte, PEO:P(VdF-HFP):LiClO4, was found to enhance at room temperature by the addition of nanoSrTiO3, and it was further confirmed through PL studies. Two ionic conductivity maxima, one at 2 wt% and another at 6 wt% of SrTiO3 were observed for NCPBEs. Out of the two peak maxima, the maximum ionic conductivity, 4.827 × 10-5 S cm-1, was obtained for 2 wt% SrTiO3. This is attributed to the increase in amorphicity of the polymer blend electrolytes, resulting from the polymer-salt-filler interactions. The crystalline and amorphous phases of the complex were identified through X-ray diffraction. The dielectric behavior was analyzed using complex dielectric permittivity (\\varepsilon^{*}), electric modulus (M^{*}), and loss tangent. From the loss tangent spectra, relaxation times were evaluated, and the relaxation is found to be consistent with the conductivity of the samples. AFM and SEM analyses revealed significant changes in the surface morphology, which is in accordance with the ionic conductivity of the samples. The thermal stability was ascertained through TG/DTA studies.

  3. Nuclear Zero Point Effects as a Function of Density in Ice-like Structures and Liquid Water from vdW-DF Ab Initio Calculations

    NASA Astrophysics Data System (ADS)

    Pamuk, Betül; Allen, Philip B.; Soler, Jose M.; Fernández-Serra, Marivi

    2014-03-01

    The contributions of nuclear zero point vibrations to the structures of liquid water and ice are not negligible. Recently, we have explained the source of an anomalous isotope shift in hexagonal ice, representing itself as an increase in the lattice volume when H is replaced by D, by calculating free energy within the quasiharmonic approximation, with ab initio density functional theory. In this work, we extend our studies to analyze the zero point effect in other ice-like structures under different densities: clathrate hydrates, LDL and HDL-like amorphous ices with different densities, and a highly dense ice phase, ice VIII. We show that there is a transition from anomalous isotope effect to normal isotope effect as the density increases. We also analyze nuclear zero point effects in liquid water using different vdW-DFs and make connections to this anomalous-normal isotope effect transition in ice. This work is supported by DOE Early Career Award No. DE-SC0003871.

  4. C. elegans fmi-1/flamingo and Wnt pathway components interact genetically to control the anteroposterior neurite growth of the VD GABAergic neurons

    PubMed Central

    Ackley, Brian D

    2013-01-01

    During development, multiple environmental cues, e.g., growth factors, cell adhesion molecules, etc., interact to influence the pattern of outgrowth of axons and dendrites in a cell-specific fashion. As a result, individual neurons may receive similar signals, but make unique choices, leading to distinct wiring within the nervous system. C. elegans has been useful in identifying molecular cues that influence neuronal development, as well as the downstream mechanisms that allow individual neurons to make cell-specific responses. Recently, we described a role for the conserved cadherin domain-containing protein, FMI-1/flamingo, in multiple stages of neural development in C. elegans. During the initial phase of neurite outgrowth, FMI-1 seems to have a relatively cell-specific effect on the VD neurons to promote the initial neurite formed to grow toward the anterior. In this capacity, FMI-1 appears to work coordinately with at least two Wnt ligands, EGL-20 and LIN-44, and multiple downstream Wnt signaling components (including LIN-17/Frizzled, DSH-1/Disheveled, and BAR-1/β-catenin). Here I will discuss some of the ideas we considered about how FMI-1 could affect neurons as they acquire their morphology during development. PMID:24778938

  5. PETN, RDX, HMX, TATB: band gap dependence on pressure under hydrostatic compression from DFT with GW and vdW corrections

    NASA Astrophysics Data System (ADS)

    Mukhanov, Andrei; Yanilkin, Alexei

    2014-03-01

    In the middle of 1990s Gilman (Gilman J. J. 1995 Phil. Mag. B, 71:6, 1057) proposed the idea that explosives transit from insulator to conductor state with following adiabatic expansion of free electrons in shockwave. One of the reasons of such a behavior of electrons is narrowing or disappearing of the fundamental band gap in explosive single crystal. It is well known that similar behavior can be simulated by DFT. But there is a severe problem of lowering the value of gap by DFT. So for quantitative prediction of narrowing of gap under pressure it is necessary to use more complicated methods like GW. From first principle calculations we determined elastic moduli for ideal crystals of PETN, RDX, HMX, and TATB. Accounting for those moduli we simulated the 0 K isotherms for hydrostatic compression of single crystal. Due to the essential role of van der Waals interaction in such materials the vdW corrections to DFT in Grimme's form was used. We obtained the dependencies for band gap on pressure under hydrostatic compression. Our preliminary results on GW calculations show that for TATB at initial uncompressed volume we have the value of gap twice a bigger in GW than in DFT.

  6. [Quality management in a combined clinic - the quality management system according to DIN EN ISO 9001 of the The German Association of Spa Accommodation Resorts e. V. (VdKB)].

    PubMed

    Eckert, H; Schulze, U

    2004-06-01

    The implementation of a quality system in health care organizations offers huge potentials for improvement and development. But the realization of such systems necessitates high investments, which small companies and family businesses often are unable to raise. The German Association of Spa Accommodation Resorts (VdKB) commissioned two consultants to develop a reasonably priced implementation concept of a DIN EN ISO 9001 quality system specially adjusted to small companies and family businesses in medical spa and rehabilitation services, which was successfully accredited in May 2003. This paper describes fundamental requirements in combine management systems, considers the pros and cons of management combines and demonstrates the practical realization of combine requirements on the example of the VdKB-combine system.

  7. Epoxy monomer adsorption on Group III (B, Al, Ga) nitride nanotubes: vdW-DF studies on mechanical and electronic properties

    NASA Astrophysics Data System (ADS)

    Ganji, M. D.; Sharifi, N.; Fereidoon, A.; Ghorbanzadeh Ahangari, M.

    2014-03-01

    The present work investigates the interaction of (6,6) and (10,0) B, Al, and Ga nitride nanotubes (BNNT, AlNNT, and GaNNT) with bisphenol-A epoxy monomers using the first-principles van der Waals density functional (vdW-DF) approach with respect to geometrical structures, interaction energies, and electronic properties. Two types of orientations for monomer adsorption are considered: (I) parallel and (II) perpendicular with the tube axis. The interaction energy for epoxy that is adsorbed on the surface of different nanotubes (for both of these states of adsorption) is calculated, and the results indicate that state (II) is more stable than state (I) for nanotube adsorption. Unlike results obtained with BNNTs/(10,0) AlNNT, the results reported herein indicate that (6,6) AlNNTs/GaNNTs can effectively interact with the epoxy monomer, and their interaction properties are dramatically changed upon exposure to these monomers. In addition, density functional calculations are performed within the generalized gradient approximation in the elastic deformation range to obtain the Young's modulus of (6,6) nanotubes and their complexes in their most stable orientation. Our results reveal that the amounts of modulus downfall of complexes are strongly influenced by the interaction between the monomer and the nanotubes. Among the investigated nanotubes, AlNNT and GaNNTs possesses the strongest interaction to the monomer, but the Young's modulus of GaNNT complex is higher than that another one. Thus, we believe that AlNNTs might be a good strategy for improving the mechanical properties of epoxy nanocomposites.

  8. A comparative study of structural and electronic properties of formaldehyde molecule on monolayer honeycomb structures based on vdW-DF prospective

    NASA Astrophysics Data System (ADS)

    Ganji, M. D.; Jameh-Bozorgi, S.; Rezvani, M.

    2016-10-01

    In order to develop the potential applications of monolayer sheets as gas sensors, the adsorption of formaldehyde (H2CO) molecule on graphene, hexagonal silicon carbide (h-SiC) as well as hexagonal aluminum nitride (h-AlN) monolayer sheets have been investigated. In this work we have used the so-called van der Waals density functional (vdW-DF) method. It was found that H2CO molecule adsorption on h-AlN nanosheet had relatively higher adsorption energy and shorter binding distance and finally much more reactive in the adsorption of H2CO compared with the h-SiC and graphene sheets. The density of states (DOS) was calculated and the results show that the highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy gap of h-AlN and h-SiC sheets is significantly reduced upon the H2CO adsorption compared to the graphene which leads to an enhancement in the electrical conductivity of respective systems. We have evaluated these findings by well-known Mulliken as well as Hirshfeld and Voronoi charges analyses for aforementioned systems. The purpose of this work is to achieve deep insights into the influence of H2CO molecule on the electronic properties of h-AlN and h-SiC monolayer sheets, and how these effects could be used to design more sensitive gas sensing devices. Based on the DFT calculation results, the h-AlN and also h-h-SiC sheets are anticipated to be potential novel sensor for detecting the presence of H2CO toxic gas.

  9. VD: Facts You Should Know.

    ERIC Educational Resources Information Center

    Blanzaco, Andre; And Others

    This booklet presents information about venereal disease to the student in a simple, step-by-step way. It includes at least one question box on almost every page, requiring the reader to become actively involved with the material which is presented. The booklet is made up of seven sections, and is accompanied by a separate booklet which contains…

  10. Cohesion and Semantics. Reports on Text Linguistics. Meddelanden Fran Stiftelsens for Abo Akademi Forskningsinstitut, Nr 41.

    ERIC Educational Resources Information Center

    Ostman, Jan-Ola, Ed.

    This collection of papers on semantics and cohesion is organized into two sections: Meaning and Semantics, and Textual Cohesion. Titles and authors are as follows: "Functional Text Semantics, Idioms, and Variability" (Jan-Ola Ostman); "On the Degree of Motivation in Signs Used in Metaphors Involving Plant Symbolism" (Ralf Norrman); "'Hence'--An…

  11. The Perils of Promiscuity: VD and Victim-Blaming

    PubMed Central

    Labonte, Ronald

    1981-01-01

    Moral and prejudicial beliefs have affected the control of venereal disease throughout history. Such victim-blaming attitudes are impediments to the implementation of an effective control program based on epidemiological concepts and findings. A host-oriented focus in control programs deflects critical attention away from deficiencies in responses of physicians and governments to disease intervention, which may well account for the continuing high disease rates. PMID:20469356

  12. Farm Water Supply and Sanitation--Pipe, Plumbing, Skills and Symbols. Student Materials. V.A. III. V-D-1, V-D-2.

    ERIC Educational Resources Information Center

    Texas A and M Univ., College Station. Vocational Instructional Services.

    Designed for use by individuals enrolled in vocational agricultural classes, these student materials deal with farm water supply, sanitation, and plumbing skills. Topics covered in the unit are maintaining the farm water supply; repairing faucets and valves, leaks in pipes and storage tanks, and water closets; clearing clogged drains and traps;…

  13. Epidemiologic Treatment in Venereal Disease—A Method to Aid in VD Control

    PubMed Central

    Mitchell, Ellis N.

    1972-01-01

    Epidemiologic therapy refers to the treatment of infectious syphilis or gonorrhea contacts without proof of laboratory diagnosis. This method of treatment is considered essential by public health authorities in the management of venereal disease, but has long been neglected in the private sector of medicine. The majority of venereal disease patients are treated by private practitioners, but apathetic attitudes, insufficient training, lack of case reporting, differing and often inadequate treatment schedules, poor follow-up and ignorance about or reluctance to use epi-treatment are all factors in our losing struggle against the current venereal disease epidemic. PMID:4635397

  14. London-vdW and EDL effects in the coalescence of oil drops

    SciTech Connect

    Deshiikan, S.R.; Papadopoulos, K.D.

    1995-09-15

    Visual observations of coalescence of n-hexadecane oil drops (70--140 {micro}m in diameter) suspended inside an aqueous phase of varying pH are reported. The oil drops are produced in situ and confined inside the aqueous-phase-filled fine capillary (100--160 {micro}m i.d.). Rapid, spontaneous coalescence was observed at low pH ({approx_lt} 2.5) as soon as two drops were very carefully brought into apparent contact. At very high pH ({approx_gt} 13.0), coalescence was observed some time after the drops made contact. No coalescence was observed at intermediate pH 5.2, 7.1, and 10.9. The coalescence times at pH 2.2 and 2.4 were less than 0.033 s. At pH 3.2, 12, and 13.1, the coalescence times were 8, 20, and 1.8 s, respectively. The coalescence time in the acidic solution of a certain pH was distinctly lower than that in the basic solution of equivalent pOH. The coalescence tendency increased with an increase in the acidity or basicity of the aqueous phase. Also, in strongly basic or acidic media, freshly formed drops were more susceptible to coalescence. Visual observations of collision interactions are qualitatively described. When two drops were made to collide, coalescence was rapid at all pH at which coalescence was previously observed for the stationary drops. Almost no coalescence was observed at the intermediate pH`s 5.2, 7.1, and 10.9, even after repeated collisions between the drops. The relative velocity of the collision interactions ranged from 100 to 2,100 {micro}m/s. The observed phenomena are explained on the basis of the London-van der Waals and electrical double layer forces, which are important either in stabilizing the thin liquid film formed between the approaching drops or in drawing the two interfaces close enough to thin the liquid film to the critical rupture thickness range. In this range, it is believed that thin liquid film properties control the rupture process.

  15. The VD Epidemic. How It Started, Where It's Going, and What to Do About It.

    ERIC Educational Resources Information Center

    Lasagna, Louis

    This book concerning the venereal disease epidemic is designed to do the following two things: (1) to give the general public straightforward, explicit information on this ancient disease; and (2) to transform the current mood of complacency into a demand that eradication programs be set in motion at once. This book is all-encompassing in scope…

  16. Sitzungsberichte der Heidelberger Akademie der Wissenschaften> " Jahrgang 1990 Sitzungsber.Heidelberg 90 " "Gott hat die Natur einfältig gemacht, sie aber suchen viel Künste"

    NASA Astrophysics Data System (ADS)

    Zehe, Horst

    Der Aufsatz demonstriert anhand ausgiebig kommentierter zeitgenössischer Zeugnisse Goethes Reaktion auf die Arbeiten Fraunhofers, insbesondere auf die Entdeckung der dunklen Linien im Sonnenspektrum. Den Fehlurteilen Goethes werden dabei die Urteile zeitgenössischer Physiker wie Chladni und J.F.W. Herschel gegenübergestellt. Bislang noch ungedruckte Dokumente aus dem Weimarer Goethe- und Schiller-Archiv belegen, daß sich Goethe nicht nur literarisch mit Fraunhofer beschäftigte, sondern daß er auch dessen Versuche mit Hilfe des Jenaer Universitätsmechanikers Körner getreulich zu wiederholen suchte.

  17. Conversational and clear speech intelligibility of /bVd/ syllables produced by native and non-native English speakers.

    PubMed

    Rogers, Catherine L; DeMasi, Teresa M; Krause, Jean C

    2010-07-01

    The ability of native and non-native speakers to enhance intelligibility of target vowels by speaking clearly was compared across three talker groups: monolingual English speakers and native Spanish speakers with either an earlier or a later age of immersion in an English-speaking environment. Talkers produced the target syllables "bead, bid, bayed, bed, bad" and "bod" in 'conversational' and clear speech styles. The stimuli were presented to native English-speaking listeners in multi-talker babble with signal-to-noise ratios of -8 dB for the monolingual and early learners and -4 dB for the later learners. The monolinguals and early learners of English showed a similar average clear speech benefit, and the early learners showed equal or greater intelligibility than monolinguals for most target vowels. The 4-dB difference in signal-to-noise ratio yielded approximately equal average intelligibility for the monolinguals and later learners. The average clear speech benefit was smallest for the later learners, and a significant clear speech decrement was obtained for the target syllable "bid." These results suggest that later learners of English as a second language may be less able than monolinguals to accommodate listeners in noisy environments, due to a reduced ability to improve intelligibility by speaking more clearly. PMID:20649235

  18. New spreading law of thin film liquids controlled by gravity and vdW forces under thermal fluctuations

    NASA Astrophysics Data System (ADS)

    Nesic, Svetozar; Cuerno Rejado, Rodolfo; Moro Egido, Esteban

    2013-11-01

    It has been shown that, in the regime controlled by surface tension, the spreading dynamics of a thin viscous fluid droplet changes significantly when it is subjected to thermal fluctuations. Technically, this has been accomplished through the incorporation of appropriate stochastic terms into the standard lubrication equation. In practice, it leads to a modification of the classic Tanner's law for spreading, with implications for Micro and Nanofluidic systems. We have recently found a new law of spreading for the same kind of systems, but in the gravity-dominated regime. Moreover, in the deteministic case a finite contact angle is formed when a van der Waals attractive force is introduced to the system and we show that there is a slight change in contact angle when thermal fluctuations are taken into account. Ph.D student and a member of GISC (http://matematicas.uc3m.es/index.php/gisc).

  19. Sitzungsberichte der Heidelberger Akademie der Wissenschaften¬Jahrgang 1990 Sitzungsber.Heidelberg 90¬"Gott hat die Natur einfältig gemacht, sie aber suchen viel Künste"

    NASA Astrophysics Data System (ADS)

    Zehe, Horst

    Der Aufsatz demonstriert anhand ausgiebig kommentierter zeitgenössischer Zeugnisse Goethes Reaktion auf die Arbeiten Fraunhofers, insbesondere auf die Entdeckung der dunklen Linien im Sonnenspektrum. Den Fehlurteilen Goethes werden dabei die Urteile zeitgenössischer Physiker wie Chladni und J.F.W. Herschel gegenübergestellt. Bislang noch ungedruckte Dokumente aus dem Weimarer Goethe- und Schiller-Archiv belegen, daß sich Goethe nicht nur literarisch mit Fraunhofer beschäftigte, sondern daß er auch dessen Versuche mit Hilfe des Jenaer Universitätsmechanikers Körner getreulich zu wiederholen suchte.

  20. The structure of carbon monoxide adsorbed on the NaCl(100) surface—a combined LEED and DFT-D/vdW-DF study.

    PubMed

    Vogt, Jochen; Vogt, Birgit

    2014-12-01

    The structure of the first layer CO adsorbed on NaCl(100) is investigated experimentally by means of quantitative low-energy electron diffraction at 25 K, and theoretically by means of density functional theory. Consistent with earlier helium atom diffraction results, the monolayer structure has p(2×1) symmetry with a glide-plane along the longer axis of the unit cell. The structure analysis confirms the binding of CO via the carbon end to the NaCl(100) surface. The vertical distance of carbon above Na(+) is 2.58 ± 0.08 Å, in good agreement with geometry optimizations based on dispersion-corrected density functional theory, and 0.15 Å lower than predicted in calculations based on the nonlocal van der Waals density functional. PMID:25481162

  1. Self-Driven Photodetector and Ambipolar Transistor in Atomically Thin GaTe-MoS2 p-n vdW Heterostructure.

    PubMed

    Yang, Shengxue; Wang, Cong; Ataca, Can; Li, Yan; Chen, Hui; Cai, Hui; Suslu, Aslihan; Grossman, Jeffrey C; Jiang, Chengbao; Liu, Qian; Tongay, Sefaattin

    2016-02-01

    Heterostructure engineering of atomically thin two-dimensional materials offers an exciting opportunity to fabricate atomically sharp interfaces for highly tunable electronic and optoelectronic devices. Here, we demonstrate abrupt interface between two completely dissimilar material systems, i.e, GaTe-MoS2 p-n heterojunction transistors, where the resulting device possesses unique electronic properties and self-driven photoelectric characteristics. Fabricated heterostructure transistors exhibit forward biased rectifying behavior where the transport is ambipolar with both electron and hole carriers contributing to the overall transport. Under illumination, photoexcited electron-hole pairs are readily separated by large built-in potential formed at the GaTe-MoS2 interface efficiently generating self-driven photocurrent within <10 ms. Overall results suggest that abrupt interfaces between vastly different material systems with different crystal symmetries still allow efficient charge transfer mechanisms at the interface and are attractive for photoswitch, photodetector, and photovoltaic applications because of large built-in potential at the interface. PMID:26796869

  2. Pre-treatment VD levels and VDR receptors as potential predictors of occurrence and overall survival in paediatric patients with solid tumours-a single institution pilot study.

    PubMed

    Bienertová-Vašků, Julie; Drábová, Klára; Zlámal, Filip; Tomandl, Josef; Kýr, Michal; Šplíchal, Zbyněk; Štěrba, Jaroslav

    2016-07-01

    Recently, vitamin D has been recognized as an important player in the immune system, and multiple studies suggested its involvement in cancer, too. The aims of this study were to investigate selected single nucleotide polymorphisms (SNPs) in the VDR gene, BsmI (rs1544410; A > G), FokI (rs 2228570; C > T), TaqI (rs731236; T > C), ApaI (rs 7975232; C > T) and Cdx-2 (rs11568820; A > G), and to evaluate their possible predictive role for outcomes in patients with paediatric solid tumours. A total of 111 children with paediatric solid tumours were enrolled at the Department of Paediatric Oncology, University Hospital Brno (Brno, Czech Republic) along with a control population of 787 adults; all study subjects were available for genotyping of selected SNPs, and the prediagnostic levels of 25-hydroxycholecalciferol (25(OH)D3) and 1,25-dihydroxycholecalciferol (1,25(OH)2D3) were measured in the cases, too. In FokI, the heterozygote CT genotype was weakly associated with a decreased risk of paediatric solid cancer occurrence 0.82 (0.53-1.28), while the CC genotype was associated with a decreased risk of 0.58 (0.30-1.09), p = 0.09. The 1,25(OH)2D3 prediagnostic levels were indicative of the overall survival in the cases (β = -0.012, HR 0.988, 95 % CI (0.978-0.998), while higher prediagnostic levels of 1,25(OH)2D3 were associated with a statistically significant increase in overall mortality. We observed multiple effects of the alleles of the investigated polymorphisms and of 1,25(OH)2D3 on overall survival, regardless of the underlying disease. PMID:26768618

  3. Final report from VFL Technologies for the pilot-scale thermal treatment of Lower East Fork Poplar Creek floodplain soils. LEFPC appendices. Volume 5. Appendix V-D

    SciTech Connect

    1994-09-01

    This final report from VFL Technologies for the pilot-scale thermal treatment of lower East Fork Poplar Creek floodplain soils dated September 1994 contains LEFPC Appendices, Volume 5, Appendix V - D. This appendix includes the final verification run data package (PAH, TCLP herbicides, TCLP pesticides).

  4. Self-Driven Photodetector and Ambipolar Transistor in Atomically Thin GaTe-MoS2 p-n vdW Heterostructure.

    PubMed

    Yang, Shengxue; Wang, Cong; Ataca, Can; Li, Yan; Chen, Hui; Cai, Hui; Suslu, Aslihan; Grossman, Jeffrey C; Jiang, Chengbao; Liu, Qian; Tongay, Sefaattin

    2016-02-01

    Heterostructure engineering of atomically thin two-dimensional materials offers an exciting opportunity to fabricate atomically sharp interfaces for highly tunable electronic and optoelectronic devices. Here, we demonstrate abrupt interface between two completely dissimilar material systems, i.e, GaTe-MoS2 p-n heterojunction transistors, where the resulting device possesses unique electronic properties and self-driven photoelectric characteristics. Fabricated heterostructure transistors exhibit forward biased rectifying behavior where the transport is ambipolar with both electron and hole carriers contributing to the overall transport. Under illumination, photoexcited electron-hole pairs are readily separated by large built-in potential formed at the GaTe-MoS2 interface efficiently generating self-driven photocurrent within <10 ms. Overall results suggest that abrupt interfaces between vastly different material systems with different crystal symmetries still allow efficient charge transfer mechanisms at the interface and are attractive for photoswitch, photodetector, and photovoltaic applications because of large built-in potential at the interface.

  5. The structure of carbon monoxide adsorbed on the NaCl(100) surface—a combined LEED and DFT-D/vdW-DF study.

    PubMed

    Vogt, Jochen; Vogt, Birgit

    2014-12-01

    The structure of the first layer CO adsorbed on NaCl(100) is investigated experimentally by means of quantitative low-energy electron diffraction at 25 K, and theoretically by means of density functional theory. Consistent with earlier helium atom diffraction results, the monolayer structure has p(2×1) symmetry with a glide-plane along the longer axis of the unit cell. The structure analysis confirms the binding of CO via the carbon end to the NaCl(100) surface. The vertical distance of carbon above Na(+) is 2.58 ± 0.08 Å, in good agreement with geometry optimizations based on dispersion-corrected density functional theory, and 0.15 Å lower than predicted in calculations based on the nonlocal van der Waals density functional.

  6. The mitogen-activated protein kinase gene, VdHog1, regulates osmotic stress response, microsclerotia formation and virulence in Verticillium dahliae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fungus Verticillium dahliae has gained worldwide notoriety as a destructive plant pathogen, causing vascular wilt diseases on diverse plant species. The fungus produces melanized resting bodies, known as microsclerotia that can survive for 15 years in the soil, and are thus critically important ...

  7. The structure of carbon monoxide adsorbed on the NaCl(100) surface—A combined LEED and DFT-D/vdW-DF study

    SciTech Connect

    Vogt, Jochen; Vogt, Birgit

    2014-12-07

    The structure of the first layer CO adsorbed on NaCl(100) is investigated experimentally by means of quantitative low-energy electron diffraction at 25 K, and theoretically by means of density functional theory. Consistent with earlier helium atom diffraction results, the monolayer structure has p(2×1) symmetry with a glide-plane along the longer axis of the unit cell. The structure analysis confirms the binding of CO via the carbon end to the NaCl(100) surface. The vertical distance of carbon above Na{sup +} is 2.58 ± 0.08 Å, in good agreement with geometry optimizations based on dispersion-corrected density functional theory, and 0.15 Å lower than predicted in calculations based on the nonlocal van der Waals density functional.

  8. A Resource Manual for the Development and Evaluation of Special Programs for Exceptional Students. Volume V-D: Techniques of Precision Teaching. Part 1: Training Manual, Part 2: Math Basic Skills Curriculum, Part 3: Reading Basic Skills Curriculum.

    ERIC Educational Resources Information Center

    Diviaio, Linda G.; Hefferan, Marilyn P.

    This document contains a training manual and reading and math basic skills curricula for use in specific learning disability programs and/or with educably mentally handicapped and emotionally handicapped students. The training manual is intended to help special education teachers understand and use precision teaching. A brief history of the…

  9. An Information Analysis of 2-, 3-, and 4-Word Verbal Discrimination Learning.

    ERIC Educational Resources Information Center

    Arima, James K.; Gray, Francis D.

    Information theory was used to qualify the difficulty of verbal discrimination (VD) learning tasks and to measure VD performance. Words for VD items were selected with high background frequency and equal a priori probabilities of being selected as a first response. Three VD lists containing only 2-, 3-, or 4-word items were created and equated for…

  10. [The fight against venereal diseases in different political systems].

    PubMed

    Scholz, A

    2003-07-01

    The fight against venereal diseases (VD) has often been influenced by the prevailing political and social conditions. At the end of 19th century the increase of VD demanded new strategies. In 1902 the German Society for the Control of VD was founded in Berlin. It was then followed by the foundation of the International Society against VD in Brussels in 1899. In the German empire and during the Nazi regime, authoritarian structures dominated the strategies against VD. The individual had to submit the interests of the society. Sociopolitical aspects influenced the discussions in the fight against VD during the Weimar republic. In 1927 the new laws to control VD met liberal demands.

  11. Drug-drug co-crystallization presents a new opportunity for the development of stable vitamins.

    PubMed

    Wang, Jian-Rong; Yu, Qihui; Dai, Wenjuan; Mei, Xuefeng

    2016-02-28

    Drug-drug co-crystallization could realize combination drugs at a molecular level. Two polymorphic co-crystals between VD2 and VD3 were successfully designed and synthesized. These enantiotropic polymorphs exhibit significantly different physicochemical stabilities.

  12. Serum vitamin D levels in children with newly diagnosed and chronic immune thrombocytopenia.

    PubMed

    Čulić, Srđana; Markić, Joško; Petrović, Davor; Konjevoda, Paško; Pavelić, Jasminka

    2016-04-01

    The primary objective of the study was to assess the vitamin D (VD) status of patients suffering from ITP. Children from the case cohort (total 21) were recruited from chronic ITP patients (followed as outpatients) and newly diagnosed ITP (prospective study) patients. VD deficiency (values <75 nmol/L) was detected in 11 patients with newly diagnosed ITP, and seven patients with chronic ITP. Only three patients with newly diagnosed, and none with chronic ITP had normal VD values. Newly diagnosed ITP patients had statistically significantly higher values (P <.044) of VD than the patients with chronic type of ITP. Platelets values did not follow VD level. VD deficiency is very common in children with either newly diagnosed or chronic ITP form. Therefore there is a utility supplementing VD in these patients. To investigate the role of VD as an immune modulating drug for patients with ITP, a prospective randomized placebo-controlled trial needs to be performed. PMID:27312171

  13. Exploring an ultracold Fermi-Fermi mixture: interspecies Feshbach resonances of ^6Li-^40K

    NASA Astrophysics Data System (ADS)

    Schreck, Florian

    2008-03-01

    We report on the observation of interspecies Feshbach resonances in an ultracold mixture of two fermionic species, ^6Li and ^40K. Interpretation of the data unambiguously assigns molecular bound states to the various resonances and fully characterizes the ground-state scattering properties in any combination of spin states. Using this knowledge we hope to be able to produce ^6Li-^40K molecules, cool them to quantum degeneracy, and study their BEC-BCS crossover. In collaboration with: F. Schreck, Institut fuer Quantenoptik und Quanteninformation, Oesterreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria; E. Wille, Institut fuer Quantenoptik und Quanteninformation, Oesterreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria and Institut fuer Experimentalphysik und Forschungszentrum fuer Quantenphysik, Universitaet Innsbruck, 6020 Innsbruck, Austria; F.M. Spiegelhalder, G. Kerner, D. Naik, A. Trenkwalder, G. Hendl, Institut fuer Quantenoptik und Quanteninformation, Oesterreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria; R. Grimm, Institut fuer Quantenoptik und Quanteninformation, Oesterreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria and Institut fuer Experimentalphysik und Forschungszentrum fuer Quantenphysik, Universitaet Innsbruck, 6020 Innsbruck, Austria; T.G. Tiecke, J.T.M. Walraven,Van der Waals-Zeeman Institute of the University of Amsterdam, 1018 XE, The Netherlands; S.J.J.M.F. Kokkelmans, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; E. Tiesinga, P.S. Julienne, Joint Quantum Institute, National Institute of Standards and Technology and University of Maryland, Gaithersburg, Maryland 20899-8423, USA

  14. Content and Language Integrated Learning: Teachers' and Teacher Educators' Experiences of English Medium Teaching. Publication No. 4.

    ERIC Educational Resources Information Center

    Sjoholm, Kaj, Ed.; Bjorklund, Mikaela, Ed.

    The publication on the integration of content area and second language instruction, focusing on the situation in Finland, consists of nine essays and a bibliography. The essays include: "Education in a Second or Foreign Language. An Overview" (Kaj Sjoholm); "Foreign Language Content Teaching in Teacher Education at Abo Akademi University" (Kaj…

  15. Vitamin D metabolism, sex hormones, and male reproductive function.

    PubMed

    Blomberg Jensen, Martin

    2012-08-01

    The spectrum of vitamin D (VD)-mediated effects has expanded in recent years, and VD is now recognized as a versatile signaling molecule rather than being solely a regulator of bone health and calcium homeostasis. One of the recently identified target areas of VD is male reproductive function. The VD receptor (VDR) and the VD metabolizing enzyme expression studies documented the presence of this system in the testes, mature spermatozoa, and ejaculatory tract, suggesting that both systemic and local VD metabolism may influence male reproductive function. However, it is still debated which cell is the main VD target in the testis and to what extent VD is important for sex hormone production and function of spermatozoa. This review summarizes descriptive studies on testicular VD metabolism and spatial distribution of VDR and the VD metabolizing enzymes in the mammalian testes and discusses mechanistic and association studies conducted in animals and humans. The reviewed evidence suggests some effects of VD on estrogen and testosterone biosynthesis and implicates involvement of both systemic and local VD metabolism in the regulation of male fertility potential.

  16. Serum Metabolite Profiles and Target Tissue Gene Expression Define the Effect of Cholecalciferol Intake on Calcium Metabolism in Rats and Mice1,2

    PubMed Central

    Fleet, James C.; Gliniak, Christy; Zhang, Zhentao; Xue, Yingben; Smith, Kathleen B.; McCreedy, Rebecca; Adedokun, Sunday A.

    2008-01-01

    We studied the effect of cholecalciferol (VD3) intake on VD3 status and markers of calcium (Ca) homeostasis in mice and rats. Serum 25 hydroxycholecalciferol (25OH-VD3) concentrations were increased in animals fed diets containing 400–20,000 international units (IU) VD3/kg (37 nmol·L−1·1000 IU VD3−1), but body weight, serum Ca, and duodenal gene expression were not altered. High-VD3 intake decreased serum 1, 25-dihydroxycholecalciferol [1,25(OH)2-VD3] and renal 25 hydroxycholecalciferol-1ahydroxylase (CYP27B1) mRNA, suggesting that rodents tolerate high-VD3 intake by suppressing the activity of the VD3 endocrine system. Serum 25OH-VD3 declined when animals were fed diets containing 1000 to 25 IU VD3/kg (9–11 wk, inflection at 200 IU/kg, 4-fold steeper slope below this). Neither body weight nor serum Ca were influenced by low-VD3 intake. However, mice fed the 25-IU/kg diet had lower serum 1,25(OH)2-VD3, duodenal calbindin D9k mRNA, bone mineral density, and renal 25 hydroxycholecalciferol-24 hydroxylase mRNA, whereas renal CYP27B1 mRNA was elevated when rodents were fed ,200 IU VD3/kg. These data reveal a stress on VD3 and Ca metabolism at low dietary VD3 intake. Dietary Ca restriction (0.25 vs. 0.5%, 9 wk) increased serum 1,25(OH)2-VD3 and was 30% greater in rats fed a 10,000-IU VD3/kg diet. High-VD3 intake did not prevent Ca restriction-induced bone loss. Our data show that modeling human VD3 status requires lower intake than the current NRC rodent requirement (1000-IU/kg diet). Also, although rodents are very tolerant of high-VD3 intake, it cannot compensate for moderate Ca restriction. PMID:18492843

  17. Structural evidence for enhancement of sequential vitamin D3 hydroxylation activities by directed evolution of cytochrome P450 vitamin D3 hydroxylase.

    PubMed

    Yasutake, Yoshiaki; Fujii, Yoshikazu; Nishioka, Taiki; Cheon, Woo-Kwang; Arisawa, Akira; Tamura, Tomohiro

    2010-10-01

    Vitamin D(3) hydroxylase (Vdh) isolated from actinomycete Pseudonocardia autotrophica is a cytochrome P450 (CYP) responsible for the biocatalytic conversion of vitamin D(3) (VD(3)) to 1α,25-dihydroxyvitamin D(3) (1α,25(OH)(2)VD(3)) by P. autotrophica. Although its biological function is unclear, Vdh is capable of catalyzing the two-step hydroxylation of VD(3), i.e. the conversion of VD(3) to 25-hydroxyvitamin D(3) (25(OH)VD(3)) and then of 25(OH)VD(3) to 1α,25(OH)(2)VD(3), a hormonal form of VD(3). Here we describe the crystal structures of wild-type Vdh (Vdh-WT) in the substrate-free form and of the highly active quadruple mutant (Vdh-K1) generated by directed evolution in the substrate-free, VD(3)-bound, and 25(OH)VD(3)-bound forms. Vdh-WT exhibits an open conformation with the distal heme pocket exposed to the solvent both in the presence and absence of a substrate, whereas Vdh-K1 exhibits a closed conformation in both the substrate-free and substrate-bound forms. The results suggest that the conformational equilibrium was largely shifted toward the closed conformation by four amino acid substitutions scattered throughout the molecule. The substrate-bound structure of Vdh-K1 accommodates both VD(3) and 25(OH)VD(3) but in an anti-parallel orientation. The occurrence of the two secosteroid binding modes accounts for the regioselective sequential VD(3) hydroxylation activities. Moreover, these structures determined before and after directed evolution, together with biochemical and spectroscopic data, provide insights into how directed evolution has worked for significant enhancement of both the VD(3) 25-hydroxylase and 25(OH)VD(3) 1α-hydroxylase activities.

  18. Modifying atom-surface interactions with optical fields

    NASA Astrophysics Data System (ADS)

    Perreault, John D.; Bhattacharya, M.; Lonij, Vincent P. A.; Cronin, Alexander D.

    2008-04-01

    The ability to control matter on the nanometer scale is greatly influenced by the van der Waals (vdW) interaction. Therefore, understanding and manipulating the vdW interaction is of interest to the fields of nanotechnology and atom optics. We show that near-resonant light can significantly modify atom-surface vdW interactions in the nonretarded regime. A theory based on quantized electromagnetic fields is used to calculate (1) the ordinary vdW interaction, (2) corrections to the ordinary vdW interaction due to thermal radiation, and (3) modifications to the ordinary vdW interaction that result from monochromatic (laser) radiation. Near-resonant laser light with an intensity of 5W/cm2 is predicted to double the vdW interaction strength for sodium atoms, and possible experiments to detect this effect are discussed.

  19. [The fight against venereal diseases in different political systems].

    PubMed

    Scholz, A

    2003-07-01

    The fight against venereal diseases (VD) has often been influenced by the prevailing political and social conditions. At the end of 19th century the increase of VD demanded new strategies. In 1902 the German Society for the Control of VD was founded in Berlin. It was then followed by the foundation of the International Society against VD in Brussels in 1899. In the German empire and during the Nazi regime, authoritarian structures dominated the strategies against VD. The individual had to submit the interests of the society. Sociopolitical aspects influenced the discussions in the fight against VD during the Weimar republic. In 1927 the new laws to control VD met liberal demands. PMID:12835867

  20. Adsorption of large hydrocarbons on coinage metals: a van der Waals density functional study.

    PubMed

    Björk, Jonas; Stafström, Sven

    2014-09-15

    The adsorption of organic molecules onto the close-packed facets of coinage metals is studied, and how accurately adsorption heights can be described by using recent advances of the van der Waals density functional (vdWDF), with optPBE/vdWDF, optB86b/vdWDF, vdWDF2, and rev/vdWDF2 functionals is illustrated. The adsorption of two prototypical aromatic hydrocarbons is investigated, and the calculated adsorption heights are compared to experimental literature values from normal incident X-ray standing wave absorption and a state-of-the-art semi-empirical method. It is shown that both the optB86b/vdWDF and rev/vdWDF2 functionals describe adsorption heights with an accuracy of 0.1 Å, compared to experimental values, and are concluded as reliable methods of choice for related systems.

  1. Health impact of air pollution to children.

    PubMed

    Sram, Radim J; Binkova, Blanka; Dostal, Miroslav; Merkerova-Dostalova, Michaela; Libalova, Helena; Milcova, Alena; Rossner, Pavel; Rossnerova, Andrea; Schmuczerova, Jana; Svecova, Vlasta; Topinka, Jan; Votavova, Hana

    2013-08-01

    Health impact of air pollution to children was studied over the last twenty years in heavily polluted parts of the Czech Republic during. The research program (Teplice Program) analyzed these effects in the polluted district Teplice (North Bohemia) and control district Prachatice (Southern Bohemia). Study of pregnancy outcomes for newborns delivered between 1994 and 1998 demonstrated that increase in intrauterine growth retardation (IUGR) was associated with PM10 and c-PAHs exposure (carcinogenic polycyclic aromatic hydrocarbons) in the first month of gestation. Morbidity was followed in the cohort of newborns (N=1492) up to the age of 10years. Coal combustion in homes was associated with increased incidence of lower respiratory track illness and impaired early childhood skeletal growth up to the age of 3years. In preschool children, we observed the effect of increased concentrations of PM2.5 and PAHs on development of bronchitis. The Northern Moravia Region (Silesia) is characterized by high concentrations of c-PAHs due to industrial air pollution. Exposure to B[a]P (benzo[a]pyrene) in Ostrava-Radvanice is the highest in the EU. Children from this part of the city of Ostrava suffered higher incidence of acute respiratory diseases in the first year of life. Gene expression profiles in leukocytes of asthmatic children compared to children without asthma were evaluated in groups from Ostrava-Radvanice and Prachatice. The results suggest the distinct molecular phenotype of asthma bronchiale in children living in polluted Ostrava region compared to children living in Prachatice. The effect of exposure to air pollution to biomarkers in newborns was analyzed in Prague vs. Ceske Budejovice, two locations with different levels of pollution in winter season. B[a]P concentrations were higher in Ceske Budejovice. DNA adducts and micronuclei were also elevated in cord blood in Ceske Budejovice in comparison to Prague. Study of gene expression profiles in the cord blood showed

  2. Adsorption of thiophene on Pt, Pd, Au, and Rh(100) surfaces with the role of the van der Waals' interaction

    NASA Astrophysics Data System (ADS)

    Malone, Walter; Matos, Jeronimo; Kara, Abdelkader

    We explore the adsorption of thiophene (C4H4S) on Pt(100), Au(100), Pd(100), and Rh(100) surfaces using density functional theory with and without self-consistent van der Waals interactions (vdWs). The six functionals we use are PBE, optB86b-vdW, optB88-vdW, optPBE-vdW, revPBE-vdW, and rPW86-vdW2. We examine a variety of adsorption sites with the molecule's plane both parallel and perpendicular to the surface. In the case of parallel adsorption the highest binding energy occurs when the molecule is centered over a hollow site with the sulfur atom near an atop site. The highest adsorption energy for perpendicular configurations is achieved when the sulfur atom lies over a bridge site and the carbon atoms near hollow sites. We find that for thiophene on the coinage metals the vdW functionals predict higher adsorption energies than those predicted by the PBE functional. On the other hand, for thiophene on the reactive transition metal substrates only optB86b-vdW, optB88-vdW, and optPBE-vdW result in an enhancement in the adsorption energy over the PBE value. We also explore some of the electronic properties of the system including charge transfer and change in the work function. Our results indicate that adsorption characteristics depends heavily on the functional used and geometry.

  3. Role of nitric oxide in the anti-tumoral effect of retinoic acid and 1,25-dihydroxyvitamin D3 on human promonocytic leukemic cells.

    PubMed

    Dugas, N; Mossalayi, M D; Calenda, A; Léotard, A; Bécherel, P; Mentz, F; Ouaaz, F; Arock, M; Debré, P; Dornand, J; Dugas, B

    1996-11-01

    All trans retinoic acid and vitamin D3 derivatives are well known for their antileukemic activity, while the precise mechanism of this effect remains to be clarified. Using human leukemic U937 and THP-1 promonocytic cell lines, we analyzed the effect of all-trans retinoic acid (RA) and/or 1,25-dihydroxyvitamin D3 (VD) on the generation of nitric oxide (NO), a potent antitumoral mediator. U937 cell differentiation with VD or with both RA and VD (RA/VD) correlated with gene transcription and functional expression of inducible nitric oxide synthase (iNOS). Nitrites and L-citrulline were also detected in U937 cell supernatants as soon as 24 hours following cell incubation with VD or RA/VD, but not in cells treated with RA alone. Inhibition of iNOS activity by NG-monomethyl-L-arginine (LNMMA) significantly decreased in vitro U937 cell differentiation with VD and RA/VD as shown by the expression of cell differentiation markers (CD14 and CD68) and by the capacity of these cells to undergo a luminol-dependent chemiluminescence in response to opsonized zymosan. Similar results were obtained using the THP-1 cell line strengthening the role of NO in the VD- and RA/VD-induced growth arrest and terminal differentiation of promonocytic leukemia cells.

  4. Humoral and cellular autoimmunity in women with recurrent pregnancy losses and repeated implantation failures: A possible role of vitamin D.

    PubMed

    Kwak-Kim, Joanne; Skariah, Annie; Wu, Li; Salazar, Dinorah; Sung, Nayoung; Ota, Kuniaki

    2016-10-01

    Women with recurrent pregnancy losses (RPL) and repeated implantation failures (RIF) have auto- and cellular immune abnormalities. Approximately, 20% of women with RPL have autoimmune abnormalities, particularly antiphospholipid antibodies (APA). In addition, these women have a higher prevalence of antinuclear antibody, anti-thyroperoxidase and anti-thyroglobulin antibodies, and other non-organ-specific autoantibodies. In women with RPL, the presence of autoimmunity is often associated with cellular immune abnormalities, such as increased NK cell levels and Th1/Th2 cell ratios. Vitamin D (VD) plays a major role in regulation of auto- and cellular immune abnormalities. VD deficiency is prevalent in women with RPL, and women with VD deficiency have increased auto- and cellular immune abnormalities as compared with women with normal VD levels. VD has immune regulatory effects on various immune effectors including T, B and NK cells. Potential therapeutic application of VD for RPL and RIF with auto- and cellular immune abnormalities should be explored. PMID:27491565

  5. Heterostructures based on inorganic and organic van der Waals systems

    SciTech Connect

    Lee, Gwan-Hyoung; Lee, Chul-Ho; Zande, Arend M. van der; Han, Minyong; Cui, Xu; Arefe, Ghidewon; Hone, James; Nuckolls, Colin; Heinz, Tony F.; Kim, Philip

    2014-09-01

    The two-dimensional limit of layered materials has recently been realized through the use of van der Waals (vdW) heterostructures composed of weakly interacting layers. In this paper, we describe two different classes of vdW heterostructures: inorganic vdW heterostructures prepared by co-lamination and restacking; and organic-inorganic hetero-epitaxy created by physical vapor deposition of organic molecule crystals on an inorganic vdW substrate. Both types of heterostructures exhibit atomically clean vdW interfaces. Employing such vdW heterostructures, we have demonstrated various novel devices, including graphene/hexagonal boron nitride (hBN) and MoS{sub 2} heterostructures for memory devices; graphene/MoS{sub 2}/WSe{sub 2}/graphene vertical p-n junctions for photovoltaic devices, and organic crystals on hBN with graphene electrodes for high-performance transistors.

  6. Humoral and cellular autoimmunity in women with recurrent pregnancy losses and repeated implantation failures: A possible role of vitamin D.

    PubMed

    Kwak-Kim, Joanne; Skariah, Annie; Wu, Li; Salazar, Dinorah; Sung, Nayoung; Ota, Kuniaki

    2016-10-01

    Women with recurrent pregnancy losses (RPL) and repeated implantation failures (RIF) have auto- and cellular immune abnormalities. Approximately, 20% of women with RPL have autoimmune abnormalities, particularly antiphospholipid antibodies (APA). In addition, these women have a higher prevalence of antinuclear antibody, anti-thyroperoxidase and anti-thyroglobulin antibodies, and other non-organ-specific autoantibodies. In women with RPL, the presence of autoimmunity is often associated with cellular immune abnormalities, such as increased NK cell levels and Th1/Th2 cell ratios. Vitamin D (VD) plays a major role in regulation of auto- and cellular immune abnormalities. VD deficiency is prevalent in women with RPL, and women with VD deficiency have increased auto- and cellular immune abnormalities as compared with women with normal VD levels. VD has immune regulatory effects on various immune effectors including T, B and NK cells. Potential therapeutic application of VD for RPL and RIF with auto- and cellular immune abnormalities should be explored.

  7. Controlled Synthesis of Organic/Inorganic van der Waals Solid for Tunable Light-Matter Interactions.

    PubMed

    Niu, Lin; Liu, Xinfeng; Cong, Chunxiao; Wu, Chunyang; Wu, Di; Chang, Tay Rong; Wang, Hong; Zeng, Qingsheng; Zhou, Jiadong; Wang, Xingli; Fu, Wei; Yu, Peng; Fu, Qundong; Najmaei, Sina; Zhang, Zhuhua; Yakobson, Boris I; Tay, Beng Kang; Zhou, Wu; Jeng, Horng Tay; Lin, Hsin; Sum, Tze Chien; Jin, Chuanhong; He, Haiyong; Yu, Ting; Liu, Zheng

    2015-12-16

    High-quality organic and inorganic van der Waals (vdW) solids are realized using methylammonium lead halide (CH3 NH3 PbI3 ) as the organic part (organic perovskite) and 2D inorganic monolayers as counterparts. By stacking on various 2D monolayers, the vdW solids exhibit dramatically different light emissions. Futhermore, organic/h-BN vdW solid arrays are patterned for red-light emission.

  8. Purification, characterization, and directed evolution study of a vitamin D{sub 3} hydroxylase from Pseudonocardia autotrophica

    SciTech Connect

    Fujii, Yoshikazu; Kabumoto, Hiroki; Nishimura, Kenji; Fujii, Tadashi; Yanai, Satoshi; Takeda, Koji; Tamura, Noriko; Arisawa, Akira; Tamura, Tomohiro

    2009-07-24

    Vitamin D{sub 3} (VD{sub 3}) is a fat-soluble prohormone that plays a crucial role in bone metabolism, immunity, and control of cell proliferation and cell differentiation in mammals. The actinomycete Pseudonocardia autotrophica is capable of bioconversion of VD{sub 3} into its physiologically active forms, namely, 25(OH)VD{sub 3} or 1{alpha},25(OH){sub 2}VD{sub 3}. In this study, we isolated and characterized Vdh (vitamin D{sub 3} hydroxylase), which hydroxylates VD{sub 3} from P. autotrophica NBRC 12743. The vdh gene encodes a protein containing 403 amino acids with a molecular weight of 44,368 Da. This hydroxylase was found to be homologous with the P450 belonging to CYP107 family. Vdh had the same ratio of the V{sub max} values for VD{sub 3} 25-hydroxylation and 25(OH)VD{sub 3} 1{alpha}-hydroxylation, while other enzymes showed preferential regio-specific hydroxylation on VD{sub 3}. We characterized a collection of Vdh mutants obtained by random mutagenesis and obtained a Vdh-K1 mutant by the combination of four amino acid substitutions. Vdh-K1 showed one-order higher VD{sub 3} 25-hydroxylase activity than the wild-type enzyme. Biotransformation of VD{sub 3} into 25(OH)VD{sub 3} was successfully accomplished with a Vdh-expressed recombinant strain of actinobacterium Rhodococcus erythropolis. Vdh may be a useful enzyme for the production of physiologically active forms of VD{sub 3} by a single cytochrome P450.

  9. Neuroanatomic and behavioral correlates of urinary dysfunction induced by vaginal distension in rats.

    PubMed

    Palacios, J L; Juárez, M; Morán, C; Xelhuantzi, N; Damaser, M S; Cruz, Y

    2016-05-01

    The aim of the present study was to use a model of simulated human childbirth in rats to determine the damage to genitourinary structures and behavioral signs of urinary dysfunction induced by vaginal distension (VD) in female rats. In experiment 1, the length of the genitourinary tract and the nerves associated with it were measured immediately after simulated human delivery induced by VD or sham (SH) procedures. Electroneurograms of the dorsal nerve of the clitoris (DNC) were also recorded. In experiment 2, histological characteristics of the bladder and major pelvic ganglion of VD and SH rats were evaluated. In experiment 3, urinary parameters were determined in conscious animals during 6 h of dark and 6 h of light before and 3 days after VD or SH procedures. VD significantly increased distal vagina width (P < 0.001) and the length of the motor branch of the sacral plexus (P < 0.05), DNC (P < 0.05), and vesical nerves (P < 0.01) and decreased DNC frequency and amplitude of firing. VD occluded the pelvic urethra, inducing urinary retention, hematomas in the bladder, and thinness of the epithelial (P < 0.05) and detrusor (P < 0.01) layers of the bladder. Major pelvic ganglion parameters were not modified after VD. Rats dripped urine in unusual places to void, without the stereotyped behavior of micturition after VD. The neuroanatomic injuries after VD occur alongside behavioral signs of urinary incontinence as determined by a new behavioral tool for assessing micturition in conscious animals. PMID:26936873

  10. Relationship between clinical signs and pulmonary function estimated by the single breath diagram for CO(2) (SBD-CO(2)) in horses with chronic obstructive pulmonary disease.

    PubMed

    Herholz, C; Straub, R; Gerber, V; Wampfler, B; Lüthi, S; Imhof, A; Moens, Y; Busato, A

    2002-03-01

    The pulmonary health of 66 horses was assessed by a clinical examination and simple supplementary diagnostic methods. Single breath diagrams for CO(2) (SBD-CO(2)) and derived lung function indices were used to determine pulmonary function. The clinical signs in different groups were related to the results of the lung function indices derived from the SBD-CO(2). In horses with moderate to severe chronic obstructive pulmonary disease (COPD), a significant relationship was found between the respiratory frequency and the ratio of Bohr's dead space to the tidal volume (VD(Bohr)/VT), and between the physiological dead space/tidal volume ratio (VD(phys)/VT) and the ratio of the alveolar dead space to the alveolar tidal volume (VD(alv)/VT(alv)), but no significant associations were found between the arterial oxygen tension (P(a)O(2)) and lung function indices derived from the SBD-CO(2). The occurrence of cough, the viscosity of tracheobronchial mucus and the amount of polynuclear neutrophils in tracheobronchial aspirates were significantly related to the expiratory tidal volume (VT), the total expired volume of CO(2) (VCO(2)), VD(Bohr)/VT, VD(phys)/VT and VD(alv)/VT(alv). We conclude that abnormal findings in these clinical parameters indicate a measurable ventilation and perfusion (V(A)/Q) mismatch which is reflected by increases in dead space, VD(Bohr)/VT and VD(phys)/VT as well as VD(alv)/VT(alv).

  11. Construction of van der Waals magnetic tunnel junction using ferromagnetic layered dichalcogenide

    SciTech Connect

    Arai, Miho; Moriya, Rai Yabuki, Naoto; Masubuchi, Satoru; Ueno, Keiji; Machida, Tomoki

    2015-09-07

    We investigate the micromechanical exfoliation and van der Waals (vdW) assembly of ferromagnetic layered dichalcogenide Fe{sub 0.25}TaS{sub 2}. The vdW interlayer coupling at the Fe-intercalated plane of Fe{sub 0.25}TaS{sub 2} allows exfoliation of flakes. A vdW junction between the cleaved crystal surfaces is constructed by dry transfer method. We observe tunnel magnetoresistance in the resulting junction under an external magnetic field applied perpendicular to the plane, demonstrating spin-polarized tunneling between the ferromagnetic layered material and the vdW junction.

  12. Verticillium dahliae Sge1 differentially regulates expression of candidate effector genes.

    PubMed

    Santhanam, Parthasarathy; Thomma, Bart P H J

    2013-02-01

    The ascomycete fungus Verticillium dahliae causes vascular wilt diseases in hundreds of dicotyledonous plant species. However, thus far, only few V. dahliae effectors have been identified, and regulators of pathogenicity remain unknown. In this study, we investigated the role of the V. dahliae homolog of Sge1, a transcriptional regulator that was previously implicated in pathogenicity and effector gene expression in Fusarium oxysporum. We show that V. dahliae Sge1 (VdSge1) is required for radial growth and production of asexual conidiospores, because VdSge1 deletion strains display reduced radial growth and reduced conidia production. Furthermore, we show that VdSge1 deletion strains have lost pathogenicity on tomato. Remarkably, VdSge1 is not required for induction of Ave1, the recently identified V. dahliae effector that activates resistance mediated by the Ve1 immune receptor in tomato. Further assessment of the role of VdSge1 in the induction of the nine most highly in-planta-induced genes that encode putative effectors revealed differential activity. Although the expression of one putative effector gene in addition to Ave1 was not affected by VdSge1 deletion, VdSge1 appeared to be required for the expression of six putative effector genes, whereas two of the putative effectors genes were found to be negatively regulated by VdSge1. In conclusion, our data suggest that VdSge1 differentially regulates V. dahliae effector gene expression.

  13. [Study on spectral line profile of volume discharge and surface discharge in dielectric barrier discharge].

    PubMed

    Dong, Li-Fang; Zhao, Long-Hu; Wang, Yong-Jie; Gao, Ye-Nan

    2014-02-01

    The volume discharge (VD) and surface discharge (SD) were observed in dielectric barrier discharge with a relatively large discharge gap simultaneously by using a high-speed camera. The variations of the spectral line profiles of VD and SD as a function of the discharge parameters were studied by using optical emission spectra. The changes in the width and shift of Ar I (2P2-->1S5) spectral lines of VD and SD with gas pressure and discharge gap were measured in dielectric barrier discharge in argon. It was found that both the width and shift of SD are bigger than those of VD, indicating that the electron density of SD is higher than that of VD. The width and shift of VD and SD increase with the gas pressure increasing, indicating that the electron density of VD and SD increases with the gas pressure increasing. The width of VD and SD increases with the gas gap d increasing from 3. 8 to 4. 4 mm, reflecting that the electron density of VD and SD increases with d increasing.

  14. Prevalence and risk factors for low vitamin D status among breastfeeding mother–infant dyads in an environment with abundant sunshine

    PubMed Central

    Salameh, Khalil; Al-Janahi, Najah Saleh Ali; Reedy, Adriana M; Dawodu, Adekunle

    2016-01-01

    Purpose Evaluation of vitamin D (vD) status and risk factors for low vD among breastfeeding mother–infant dyads in a population at high risk for vD deficiency. Subjects and methods We measured serum 25-hydroxyvitamin D (25(OH)D) and parathyroid hormone at 1 month postpartum in 60 consecutive exclusively breastfeeding Arab mother–infant dyads enrolled in a high dose vD supplementation study to prevent vD deficiency in Doha, Qatar, (latitude 25°N) during summer months. Data were collected on demography, sun exposure, and vD supplementation. Comparison with a US cohort was evaluated. vD deficiency was defined as serum 25(OH)D <50 nmol/L and severe deficiency categorized as 25(OH)D <25 nmol/L in mothers and infants. Results Mean maternal age was 29 years and 77% had college or university education. Maternal median 25(OH)D was 32.5 nmol/L and 78% were vD-deficient and 20% had 25(OH)D <25 nmol/L. Only 42% of mothers had reportedly taken vD supplements postpartum and median dietary vD intake (119 IU/day) and calcium (490 mg/day) were low. Maternal median sun index score (sun exposure [hours/week] × body surface area exposed while outdoors) was 0. Maternal 25(OH)D correlated with percent body surface area exposure while outdoors (rs=0.37, P=0.004). Infant median 25(OH)D was 20 nmol/L and 83% were deficient, while 58% had 25(OH)D <25 nmol/L. Infant 25(OH)D correlated with maternal levels (rs=0.41, P=0.001). None of the infants received vD supplement at 1 month of age and median sun index score was 0. Infant’s parathyroid hormone showed negative correlations with 25(OH)D (rs=−0.28, P=0.03). Sun exposure, vD supplementation rate, and vD status were lower in Doha than Cincinnati, US cohort. Conclusion vD deficiency is common in breastfeeding mother–infant dyads in this sunny environment and is associated with sun avoidance and low vD intake. We suggest corrective vD supplement of breastfeeding mothers and their infants, which should preferably start during

  15. States of low pulmonary blood flow can be detected non-invasively at the bedside measuring alveolar dead space.

    PubMed

    Tusman, Gerardo; Suarez-Sipmann, Fernando; Paez, Gabriel; Alvarez, Jorge; Bohm, Stephan H

    2012-06-01

    We tested whether the ratio of alveolar dead space to alveolar tidal volume (VD(alv)/VT(alv)) can detect states of low pulmonary blood flow (PBF) in a non-invasive way. Fifteen patients undergoing cardiovascular surgeries with cardiopulmonary bypass (CPB) were studied. CPB is a technique that excludes the lungs from the general circulation. The weaning of CPB is a model that manipulates PBF in vivo because each time blood flow through the CPB decreases, expected PBF (ePBF) increases. Patients were liberated from CPB in steps of 20 % every 2' starting from 100 % CPB (very low ePBF) to 0 % CPB (100 % ePBF). During constant ventilation, volumetric capnograms were recorded and Bohr's dead space ratio (VD(Bohr)/VT), VD(alv)/VT(alv) and the ratio of airway dead space to tidal volume (VD(aw)/VT) were calculated. Before CPB, VD(Bohr)/VT was 0.36 ± 0.05, VD(aw)/VT 0.21 ± 0.04 and VD(alv)/VT(alv) 0.18 ± 0.06 (mean ± SD). During weaning from CPB, VD(aw)/VT remained unchanged while VD(Bohr)/VT and VD(alv)/VT(alv) decreased with increasing ePBF. At CPB of 80, 60, 40 and 20 % VD(Bohr)/VT was 0.64 ± 0.06, 0.55 ± 0.06, 0.47 ± 0.05 and 0.40 ± 0.04, respectively; p < 0.001 and VD(alv)/VT(alv) 0.53 ± 0.07, 0.40 ± 0.07, 0.29 ± 0.06 and 0.25 ± 0.04, respectively; p < 0.001). After CPB, VD(Bohr)/VT and VD(alv)/VT(alv) reached values similar to baseline (0.37 ± 0.04 and 0.19 ± 0.06, respectively). At constant ventilation the alveolar component of VD(Bohr)/VT increased in proportion to the deficit in lung perfusion.

  16. Vitamin D supplementation improves pathophysiology in a rat model of preeclampsia.

    PubMed

    Faulkner, Jessica L; Cornelius, Denise C; Amaral, Lorena M; Harmon, Ashlyn C; Cunningham, Mark W; Darby, Marie M; Ibrahim, Tarek; Thomas, D'Andrea S; Herse, Florian; Wallukat, Gerd; Dechend, Ralf; LaMarca, Babbette

    2016-02-15

    Deficiency of vitamin D (VD) is associated with preeclampsia (PE), a hypertensive disorder of pregnancy characterized by proinflammatory immune activation. We sought to determine whether VD supplementation would reduce the pathophysiology and hypertension associated with the reduced uterine perfusion pressure (RUPP) rat model of PE. Normal pregnant (NP) and RUPP rats were supplemented with VD2 or VD3 (270 IU and 15 IU/day, respectively) on gestation days 14-18 and mean arterial pressures (MAPs) measured on day 19. MAP increased in RUPP to 123 ± 2 mmHg compared with 102 ± 3 mmHg in NP and decreased to 113 ± 3 mmHg with VD2 and 115 ± 3 mmHg with VD3 in RUPP rats. Circulating CD4+ T cells increased in RUPP to 7.90 ± 1.36% lymphocytes compared with 2.04 ± 0.67% in NP but was lowered to 0.90 ± 0.19% with VD2 and 4.26 ± 1.55% with VD3 in RUPP rats. AT1-AA, measured by chronotropic assay, decreased from 19.5 ± 0.4 bpm in RUPPs to 8.3 ± 0.5 bpm with VD2 and to 15.4 ± 0.7 bpm with VD3. Renal cortex endothelin-1 (ET-1) expression was increased in RUPP rats (11.6 ± 2.1-fold change from NP) and decreased with both VD2 (3.3 ± 1.1-fold) and VD3 (3.1 ± 0.6-fold) supplementation in RUPP rats. Plasma-soluble FMS-like tyrosine kinase-1 (sFlt-1) was also reduced to 74.2 ± 6.6 pg/ml in VD2-treated and 91.0 ± 16.1 pg/ml in VD3-treated RUPP rats compared with 132.7 ± 19.9 pg/ml in RUPP rats. VD treatment reduced CD4+ T cells, AT1-AA, ET-1, sFlt-1, and blood pressure in the RUPP rat model of PE and could be an avenue to improve treatment of hypertension in response to placental ischemia.

  17. Molecular characterization and functional analysis of a necrosis- and ethylene-inducing, protein-encoding gene family from Verticillium dahliae.

    PubMed

    Zhou, Bang-Jun; Jia, Pei-Song; Gao, Feng; Guo, Hui-Shan

    2012-07-01

    Verticillium dahliae Kleb. is a hemibiotrophic, phytopathogenic fungus that causes wilt disease in a wide range of crops, including cotton. Successful host colonization by hemibiotrophic pathogens requires the induction of plant cell death to provide the saprophytic nutrition for the transition from the biotrophic to the necrotrophic stage. In this study, we identified a necrosis-inducing Phytophthora protein (NPP1) domain-containing protein family containing nine genes in a virulent, defoliating isolate of V. dahliae (V592), named the VdNLP genes. Functional analysis demonstrated that only two of these VdNLP genes, VdNLP1 and VdNLP2, encoded proteins that were capable of inducing necrotic lesions and triggering defense responses in Nicotiana benthamiana, Arabidopsis, and cotton plants. Both VdNLP1 and VdNLP2 induced the wilting of cotton seedling cotyledons. However, gene-deletion mutants targeted by VdNLP1, VdNLP2, or both did not affect the pathogenicity of V. dahliae V592 in cotton infection. Similar expression and induction patterns were found for seven of the nine VdNLP transcripts. Through a comparison of the conserved amino acid residues of VdNLP with different necrosis-inducing activities, combined with mutagenesis-based analyses, we identified several novel conserved amino acid residues, in addition to the known conserved heptapeptide GHRHDWE motif and the cysteine residues of the NPP domain-containing protein, that are indispensable for the necrosis-inducing activity of the VdNLP2 protein.

  18. Can l-Cysteine and Vitamin D Rescue Vitamin D and Vitamin D Binding Protein Levels in Blood Plasma of African American Type 2 Diabetic Patients?

    PubMed Central

    Kahlon, Gunjan; Bass, Pat; Levine, Steven N.; Warden, Cassandra

    2015-01-01

    Abstract Aims: Vitamin D (VD) deficiency has become a worldwide epidemic, particularly affecting African Americans (AA). VD deficiency has been implicated in the excessive rate of complications associated with diabetes in AA. Blood levels of VD binding protein (VDBP) and glutathione (GSH) are lower in AA compared with those in Caucasians. This study tested the hypothesis that lower GSH levels are linked to VDBP and VD deficiency in AA-type 2 diabetic (AA-T2D) patients. Blood was analyzed from T2D and nondiabetic subjects (N). Experiments examining GSH deficiency and l-cysteine (LC) supplementation were performed using THP-1 monocytes. Results: Plasma levels of LC, GSH, VDBP, and VD were significantly lower in AA-T2D compared with age-matched AA-N or Caucasian-T2D. Lower levels of LC and GSH showed a significant positive correlation with lower VDBP and VD levels in AA-T2D. GSH deficiency investigated using an antisense approach depleted VDBP/vitamin D receptor (VDR); LC supplementation caused significant upregulation of GSH and of VDBP/VDR, while supplementation with VD+LC caused a significantly greater GSH and VDBP/VDR upregulation compared with that of VD alone in monocytes. Innovation and Conclusion: The reported observations suggest that VD deficiency may be linked to GSH and LC status and lead to a novel hypothesis that supplementation with LC in combination with VD will be effective in increasing VD levels and reducing health disparities in AA. Antioxid. Redox Signal. 23, 688–693. PMID:25816831

  19. 14 CFR 25.629 - Aeroelastic stability requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... conditions, all combinations of altitudes and speeds encompassed by the VD/MD versus altitude envelope... constant altitude. In addition, a proper margin of stability must exist at all speeds up to VD/MD and... may be limited to Mach 1.0 when MD is less than 1.0 at all design altitudes, and (2) For...

  20. 14 CFR 25.629 - Aeroelastic stability requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... conditions, all combinations of altitudes and speeds encompassed by the VD/MD versus altitude envelope... constant altitude. In addition, a proper margin of stability must exist at all speeds up to VD/MD and... may be limited to Mach 1.0 when MD is less than 1.0 at all design altitudes, and (2) For...

  1. Impairment of vitamin D metabolism due to environmental cadmium exposure, and possible relevance to sex-related differences in vulnerability to the bone damage

    SciTech Connect

    Tsuritani, Ikiko; Honda, Ryumon; Ishizaki, Masao; Yamada, Yuichi ); Kido, Teruhiko; Nogawa, Koji )

    1992-12-01

    To determine whether depleted serum 1[alpha],25-dihydroxyvitamin D (VD) concentrations are associated with cadmium (Cd)-induced renal damage, the relationships between four indices of renal function and two indicators of bone metabolism, that is, serum VD and parathyroid hormone (PTH) concentrations, were analyzed in 30 male and 44 female subjects exposed to environmental Cd. Also, these associations were compared in male and female subjects to evaluate sex-related differences in vulnerability to the bone damage observed in Cd-exposed persons. Serum VD decreased significantly with declines in creatinine clearance and percentage tubular reabsorption of phosphate, and with increases in serum creatinine and serum [beta][sub 2]-microglobulin ([beta][sub 2]m) concentrations in the female subjects exposed to Cd, but not in the male subjects. The correlation between serum VD and PTH levels was also significant only in the females. Correlation coefficients between serum [beta][sub 2]m and VD and those between serum PTH and VD in both sexes were significantly different. These results suggest that renal damage due to Cd exposure leads to the decreases in the serum VD level and increases in serum PTH level, and that the more marked changes in serum VD and PTH in the women may play a role in the development of sex-related differences in Cd-induced bone injury.

  2. Analysis of Carbon Nanotube Metal-Semiconductor Diode Device

    NASA Technical Reports Server (NTRS)

    Yamada, Toshishige; Biegel, Bryan (Technical Monitor)

    2002-01-01

    We study recently reported drain current Id-drain voltage Vd characteristics of a carbon nanotube metal semiconductor diode device with the gate voltage Vg applied to modulate the carrier density in the nanotube. The diode was kink-shaped at the metal-semiconductor interface. It was shown that (1) larger negative Vg blocked Id more effectively in the negative Vd region, resulting in the rectifying Id-Vd characteristics, and that (2) positive Vg allowed Id in the both Vd polarities, resulting in the non-rectifying characteristics. The negative Vd was the Schottky reverse direction, judging from the negligible Id behavior for a wide region of -4 V less than Vd less than 0 V, with Vg = -4 V. Such negative Vg would attract positive charges from the metallic electrodes (charge reservoir) to the nanotube and lower the nanotube Fermi energy (EF). With larger negative Vg, the experiment showed that the Schottky forward direction (Vd greater than 0) had a smaller turn-on voltage and the Schottky reverse direction (Vd less than 0) was more resistant to the tunneling breakdown. Therefore, the majority carriers in the transport would be electrons since they can see a lower tunneling barrier (shallower built-in potential) in the forward direction when EF is lowered, and a thicker tunneling barrier (Schottky barrier) in the reverse direction due to the reduction in the electron density when EF is lowered.

  3. Virtual dimensionality analysis for hyperspectral imagery

    NASA Astrophysics Data System (ADS)

    Chang, Chein-I.; Lee, Li-Chien; Paylor, Drew

    2015-05-01

    Virtual dimensionality (VD) has been widely used to estimate number of endmembers in the past. Unfortunately, the original idea of VD was developed to specify the number of spectrally distinct signatures in hyperspectral data where there is no provided specific definition of what "spectrally distinct signatures" are. As a result, many techniques developed to estimate VD have produced various values for VD. This paper addresses this issue by develops a target specified VD (TSVD) theory where the value of VD is completely determined by targets of interest. In particular, the VD techniques can be categorized according to targets characterized by eigenvalues/eigenvectors and real target signal sources which are used for a binary composite hypothesis testing problem. For the latter case the Automatic Target Generation Process (ATGP) is particularly used to generate real target signal sources to replace eigenvalues/eigenvectors as signal sources to be used for the binary hypothesis testing problem. In order to find probability distributions under each hypothesis the extreme theory used by Maximum Orthogonal Complement Algorithm (MOCA) is used for their derivations. As a result, VD can be estimated by two types of signals sources, eigenvalues/eigenvectors along with two types of detectors, maximum likelihood detector and Neyman-Pearson detector.

  4. Genomic organization and reproductive regulation of a large lipid transfer protein in the varroa mite, Varroa destructor (Anderson & Trueman).

    PubMed

    Cabrera, A R; Shirk, P D; Duehl, A J; Donohue, K V; Grozinger, C M; Evans, J D; Teal, P E A

    2013-10-01

    The complete genomic region and corresponding transcript of the most abundant protein in phoretic varroa mites, Varroa destructor (Anderson & Trueman), were sequenced and have homology with acarine hemelipoglycoproteins and the large lipid transfer protein (LLTP) super family. The genomic sequence of VdLLTP included 14 introns and the mature transcript coded for a predicted polypeptide of 1575 amino acid residues. VdLLTP shared a minimum of 25% sequence identity with acarine LLTPs. Phylogenetic assessment showed VdLLTP was most closely related to Metaseiulus occidentalis vitellogenin and LLTP proteins of ticks; however, no heme binding by VdLLTP was detected. Analysis of lipids associated with VdLLTP showed that it was a carrier for free and esterified C12 -C22 fatty acids from triglycerides, diacylglycerides and monoacylglycerides. Additionally, cholesterol and β-sitosterol were found as cholesterol esters linked to common fatty acids. Transcript levels of VdLLTP were 42 and 310 times higher in phoretic female mites when compared with males and quiescent deutonymphs, respectively. Coincident with initiation of the reproductive phase, VdLLTP transcript levels declined to a third of those in phoretic female mites. VdLLTP functions as an important lipid transporter and should provide a significant RNA interference target for assessing the control of varroa mites.

  5. Bone characteristics of 16 wk-old turkeys subjected to different dietary regimens and simulated stress

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of a yeast extract (YE) feed supplement and/or vitamin D3 (VD) on the bone properties of 16 wk-old turkeys, transiently subjected to a simulated stress using dexamethasone (Dex), were determined. The turkeys were fed diets with or without YE and/or VD during 6, 11, and 15 wk post hatch, ...

  6. Effects of yeast extract and vitamin D on turkey mortality and cellulitis incidence in a transport stress model.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We evaluated yeast extract (YE) and vitamin D (VD) in turkeys treated with dexamethasone (Dex) at intervals designed to simulate transport stress during a 3 stage growout. YE but not VD decreased early mortality (P = 0.001) and mortality at wk 7 (P= 0.02) and wk 12 (P = 0.002) but not wk 16. Celluli...

  7. The Impact of Maternal Vitamin D Status on Offspring Brain Development and Function: a Systematic Review.

    PubMed

    Pet, Milou A; Brouwer-Brolsma, Elske M

    2016-07-01

    Various studies have examined associations between maternal vitamin D (VD) deficiency and offspring health, including offspring brain health. The purpose of this review was to summarize current evidence concerning the impact of maternal VD deficiency on brain development and function in offspring. A systematic search was conducted within Medline (on Ovid) for studies published through 7 May 2015. Animal and human studies that examined associations between maternal VD status or developmental VD deficiency and offspring brain development and function were included. A total of 26 animal studies and 10 human studies met the inclusion criteria. Several animal studies confirmed the hypothesis that low prenatal VD status may affect brain morphology and physiology as well as behavioral outcomes. In humans, subtle cognitive and psychological impairments in offspring of VD-deficient mothers were observed. However, data obtained from animal and human studies provide inconclusive evidence, and results seem to depend on strain or race and age of offspring. To conclude, prenatal VD status is thought to play an important role in brain development, cognitive function, and psychological function. However, results are inconclusive; validation of these findings and investigation of underlying mechanisms are required. Thus, more investigation is needed before recommending supplementation of VD during pregnancy to promote brain health of offspring. PMID:27422502

  8. Physisorption of nucleobases on graphene: a comparative van der Waals study.

    PubMed

    Le, Duy; Kara, Abdelkader; Schröder, Elsebeth; Hyldgaard, Per; Rahman, Talat S

    2012-10-24

    The physisorption of the nucleobases adenine (A), cytosine (C), guanine (G), thymine (T), and uracil (U) on graphene is studied using several variants of the density functional theory (DFT): the generalized gradient approximation with the inclusion of van der Waals interaction (vdW) based on the TS approach (Tkatchenko and Scheffer 2009 Phys. Rev. Lett. 102 073005) and our simplified version of this approach (here called sTS), the van der Waals density functional vdW-DF (Dion et al 2004 Phys. Rev. Lett. 92 246401) and vdW-DF2 (Lee et al 2010 Phys. Rev. B 82 081101), and DFT-D2 (Grimme 2006 J. Comput. Chem. 27 1787) and DFT-D3 (Grimme et al 2010 J. Chem. Phys. 132 154104) methods. The binding energies of nucleobases on graphene are found to be in the following order: G > A > T > C > U within TS, sTS, vdW-DF, and DFT-D2, and in the following order: G > A > T ~ C > U within DFT-D3 and vdW-DF2. The binding separations are found to be different within different methods and in the following order: DFT-D2 < TS < DFT-D3 ~ vdW-DF2 < vdW-DF. We also comment on the efficiency of combining the DFT-D approach and vdW-DF to study systems with van der Waals interactions.

  9. Physisorption of nucleobases on graphene: a comparative van der Waals study

    NASA Astrophysics Data System (ADS)

    Le, Duy; Kara, Abdelkader; Schröder, Elsebeth; Hyldgaard, Per; Rahman, Talat S.

    2012-10-01

    The physisorption of the nucleobases adenine (A), cytosine (C), guanine (G), thymine (T), and uracil (U) on graphene is studied using several variants of the density functional theory (DFT): the generalized gradient approximation with the inclusion of van der Waals interaction (vdW) based on the TS approach (Tkatchenko and Scheffer 2009 Phys. Rev. Lett. 102 073005) and our simplified version of this approach (here called sTS), the van der Waals density functional vdW-DF (Dion et al 2004 Phys. Rev. Lett. 92 246401) and vdW-DF2 (Lee et al 2010 Phys. Rev. B 82 081101), and DFT-D2 (Grimme 2006 J. Comput. Chem. 27 1787) and DFT-D3 (Grimme et al 2010 J. Chem. Phys. 132 154104) methods. The binding energies of nucleobases on graphene are found to be in the following order: G > A > T > C > U within TS, sTS, vdW-DF, and DFT-D2, and in the following order: G > A > T ˜ C > U within DFT-D3 and vdW-DF2. The binding separations are found to be different within different methods and in the following order: DFT-D2 < TS < DFT-D3 ˜ vdW-DF2 < vdW-DF. We also comment on the efficiency of combining the DFT-D approach and vdW-DF to study systems with van der Waals interactions.

  10. The Impact of Maternal Vitamin D Status on Offspring Brain Development and Function: a Systematic Review.

    PubMed

    Pet, Milou A; Brouwer-Brolsma, Elske M

    2016-07-01

    Various studies have examined associations between maternal vitamin D (VD) deficiency and offspring health, including offspring brain health. The purpose of this review was to summarize current evidence concerning the impact of maternal VD deficiency on brain development and function in offspring. A systematic search was conducted within Medline (on Ovid) for studies published through 7 May 2015. Animal and human studies that examined associations between maternal VD status or developmental VD deficiency and offspring brain development and function were included. A total of 26 animal studies and 10 human studies met the inclusion criteria. Several animal studies confirmed the hypothesis that low prenatal VD status may affect brain morphology and physiology as well as behavioral outcomes. In humans, subtle cognitive and psychological impairments in offspring of VD-deficient mothers were observed. However, data obtained from animal and human studies provide inconclusive evidence, and results seem to depend on strain or race and age of offspring. To conclude, prenatal VD status is thought to play an important role in brain development, cognitive function, and psychological function. However, results are inconclusive; validation of these findings and investigation of underlying mechanisms are required. Thus, more investigation is needed before recommending supplementation of VD during pregnancy to promote brain health of offspring.

  11. The Development of Memory-Encoding Processes. Final Report.

    ERIC Educational Resources Information Center

    Hall, James W.

    Eight experiments are described in this report. In experiment 1, four and five year olds were presented four verbal discrimination (VD) lists. For three of the lists all correct items were either conceptually, acoustically, or affectively similar. The fourth was a control list. The conceptual list facilitated VD learning. Experiment 2 indicated…

  12. Interlayer Transition and Infrared Photodetection in Atomically Thin Type-II MoTe₂/MoS₂ van der Waals Heterostructures.

    PubMed

    Zhang, Kenan; Zhang, Tianning; Cheng, Guanghui; Li, Tianxin; Wang, Shuxia; Wei, Wei; Zhou, Xiaohao; Yu, Weiwei; Sun, Yan; Wang, Peng; Zhang, Dong; Zeng, Changgan; Wang, Xingjun; Hu, Weida; Fan, Hong Jin; Shen, Guozhen; Chen, Xin; Duan, Xiangfeng; Chang, Kai; Dai, Ning

    2016-03-22

    We demonstrate the type-II staggered band alignment in MoTe2/MoS2 van der Waals (vdW) heterostructures and an interlayer optical transition at ∼1.55 μm. The photoinduced charge separation between the MoTe2/MoS2 vdW heterostructure is verified by Kelvin probe force microscopy (KPFM) under illumination, density function theory (DFT) simulations and photoluminescence (PL) spectroscopy. Photoelectrical measurements of MoTe2/MoS2 vdW heterostructures show a distinct photocurrent response in the infrared regime (1550 nm). The creation of type-II vdW heterostructures with strong interlayer coupling could improve our fundamental understanding of the essential physics behind vdW heterostructures and help the design of next-generation infrared optoelectronics. PMID:26950255

  13. Interlayer Transition and Infrared Photodetection in Atomically Thin Type-II MoTe₂/MoS₂ van der Waals Heterostructures.

    PubMed

    Zhang, Kenan; Zhang, Tianning; Cheng, Guanghui; Li, Tianxin; Wang, Shuxia; Wei, Wei; Zhou, Xiaohao; Yu, Weiwei; Sun, Yan; Wang, Peng; Zhang, Dong; Zeng, Changgan; Wang, Xingjun; Hu, Weida; Fan, Hong Jin; Shen, Guozhen; Chen, Xin; Duan, Xiangfeng; Chang, Kai; Dai, Ning

    2016-03-22

    We demonstrate the type-II staggered band alignment in MoTe2/MoS2 van der Waals (vdW) heterostructures and an interlayer optical transition at ∼1.55 μm. The photoinduced charge separation between the MoTe2/MoS2 vdW heterostructure is verified by Kelvin probe force microscopy (KPFM) under illumination, density function theory (DFT) simulations and photoluminescence (PL) spectroscopy. Photoelectrical measurements of MoTe2/MoS2 vdW heterostructures show a distinct photocurrent response in the infrared regime (1550 nm). The creation of type-II vdW heterostructures with strong interlayer coupling could improve our fundamental understanding of the essential physics behind vdW heterostructures and help the design of next-generation infrared optoelectronics.

  14. 1α, 25-Dihydroxyvitamin D3 and the vitamin D receptor regulates ΔNp63α levels and keratinocyte proliferation

    PubMed Central

    Hill, N T; Zhang, J; Leonard, M K; Lee, M; Shamma, H N; Kadakia, M

    2015-01-01

    1α, 25-dihydroxyvitamin D3 (VD3), a secosteriod that has been explored as an anti-cancer agent, was also shown to promote cell survival. Its receptor, the Vitamin D Receptor (VDR), is a direct target of the proto-oncogene ΔNp63α, which is overexpressed in non-melanoma skin cancers. The interconnection between VDR/VD3 signaling and ΔNp63α, led us to examine whether VDR/VD3 signaling promotes keratinocyte proliferation by regulating ΔNp63α levels. Our data demonstrate that VDR regulates ΔNp63α expression at both the transcript and protein level. Interestingly, although low doses of VD3 led to an increase in ΔNp63α protein levels and keratinocyte proliferation, high doses of VD3 failed to increase ΔNp63α protein levels and resulted in reduced proliferation. Increased expression of ΔNp63α by low dose VD3 was shown to be dependent on VDR and critical for the proliferative effects of VD3. VD3-mediated increases in ΔNp63α protein levels occur via activation of both p38 MAPK and Akt kinases. Finally, analysis of samples from patients with squamous cell carcinoma (SCC), basal cell carcinoma and precursors to invasive SCC demonstrated a significant correlation between p63 and VDR levels when compared with healthy normal skin control samples. Delineation of the mechanisms by which VD3 exerts its effect on ΔNp63α and cell proliferation is critical for determining the future of VD3 in cancer therapies. PMID:26068789

  15. Vitamin D deficiency rickets in an adolescent with severe atopic dermatitis.

    PubMed

    Borzutzky, Arturo; Grob, Francisca; Camargo, Carlos A; Martinez-Aguayo, Alejandro

    2014-02-01

    Atopic dermatitis (AD) affects 10% to 20% of children worldwide. Its severity may be inversely correlated with 25-hydroxyvitamin D (25OHD) levels. Although low levels of vitamin D (VD) can cause rickets in infants, VD deficiency rickets is an unusual presentation in teenagers. We report the case of a 14-year-old girl with severe AD and fish allergy since early childhood. She lived at high latitude (with less sun exposure) and, because of her atopic disorders, avoided sunlight and fish. Laboratory studies showed elevated alkaline phosphatase and parathyroid hormone levels and low serum calcium; her serum 25OHD level was <12 nmol/L. A radiograph of the wrist showed a radiolucent band in the distal metaphysis of the radius with marginal sclerosis. She was diagnosed as having hypocalcemic rickets due to VD deficiency. Treatment with VD increased her 25OHD level to 44 nmol/L, with normalization of alkaline phosphatase, parathyroid hormone, and calcium. Moreover, we observed a dramatic improvement in her AD severity with VD treatment. This case demonstrates the complex interaction between VD deficiency, AD, and food allergy. We advise a high index of suspicion of VD deficiency rickets in children of all ages with AD, particularly during accelerated growth periods and in the presence of other risk factors such as darker skin, living at high latitude, sun avoidance, and low intake of VD-rich foods. The concomitant improvement in bone-related parameters and AD severity may reflect a double benefit of VD treatment, a possibility that warrants research on VD as potential treatment for AD.

  16. Small GTPase Rac1 and its interaction partner Cla4 regulate polarized growth and pathogenicity in Verticillium dahliae.

    PubMed

    Tian, Hui; Zhou, Lei; Guo, Wangzhen; Wang, Xinyu

    2015-01-01

    Rac1 is a small GTPase coordinating diverse cellular functions such as cell polarity, vesicular trafficking, the cell cycle and transcriptional dynamics in many organisms. In this study, we investigate the biological functions of VdRac1, a Rac1 homolog in the soil-borne, wilt-causing fungus Verticillium dahliae. The VdRac1 gene was deleted in a V. dahliae virulence strain Vd8 isolated from a local cotton cultivar. ΔVdrac1 mutants display drastic reduction in colony expansion and form compact, convoluted colonies, show hyper-branching, loss of polarity and ability to penetrate, leading to severely reduced virulence. The p21-activated kinase Cla4 (named as VdCla4 in V. dahliae) null mutants ΔVdcla4 share identical phenotypes with ΔVdrac1. Yeast two-hybrid studies prove that VdCla4 is an effector of VdRac1. Localizations of actin and reactive oxygen species (ROS) in ΔVdrac1 and ΔVdcla4 compared with the corresponding wild-type strain reveal that VdRac1 and VdCla4 play a primary role in polarized hyphal growth via organization of ROS and play only a minor role in the organization of actin. The Vdrac1 and Vdcla4 null mutants are defective in conidiation and trace elements can partially compensate for the defect. Our data demonstrate that VdRac1 regulates polarized growth and pathogenicity by interacting with its effector VdCla4 in V. dahliae.

  17. Expression of Monocyte Chemotactic Protein-3 Following Simulated Birth Trauma in a Murine Model of Obesity

    PubMed Central

    Vricella, Gino J.; Tao, Mingfang; Altuntas, Cengiz Z.; Liu, Guiming; Kavran, Michael; Daneshgari, Firouz; Hijaz, Adonis K.

    2014-01-01

    Objective To determine the effect of obesity on simulated birth trauma in leptin-deficient obese mice as measured by relative MCP-3 expression. Materials and Methods A total of 25 wild-type and 25 obese C57BL/6 virgin female mice underwent 1 hour of vaginal distension (VD), sham VD or anesthesia without VD. Pelvic organ tissues were then harvested either immediately or 24-hours post VD and subsequent real-time PCR analysis was performed. Results Urethral MCP-3 levels in wild-type mice were elevated from baseline at 0-hours with a return to baseline at 24-hours in both VD and sham VD groups. In obese mice, there was a 6-fold elevation in MCP-3 levels at 0-hours after sham VD versus control (P < 0.05), which then returned to baseline levels at 24-hours. After undergoing VD, MCP-3 levels increased to 6-fold baseline values (P = 0.002) at 0-hours, with continued elevation in MCP-3 levels to 15 times control levels (P = 0.0003) at 24-hours. Conclusions MCP-3 is significantly over expressed in the urethral tissues of both wild-type and obese mice immediately after any urethral manipulation. At 24-hours, the MCP-3 expression patterns become divergent between VD and sham VD in obese mice. With a greater degree of trauma, MCP-3 continued to rise at 24-hours, suggesting that the underlying obesity resulted in alterations in response to tissue injury paralleling the degree of injury. Such associations warrant further investigation into the role of MCP-3 as a chemokine for stem cell migration with implications for subsequent tissue repair mechanisms after birth trauma. PMID:20970834

  18. Internal anatomy and ultrastructure of the male reproductive system of the Norway lobster Nephrops norvegicus (Decapoda: Astacidea).

    PubMed

    Rotllant, Guiomar; Chiva, Manel; Durfort, Mercè; Ribes, Enric

    2012-06-01

    The Norway lobster (Nephrops norvegicus) is economically important in Europe. However, apart from the female reproductive system, very little is known about its internal anatomy. This article focuses on studying the internal anatomy and ultrastructure of the male reproductive system. This system follows the general pattern found among decapod crustaceans, with several peculiarities. Testes are composed of lobular sperm ducts in which the spermatozoa are fully constituted. The spermatozoa present three lateral arms and a long acrosome, which gives a false appearance of flagellated spermatozoa. The two testes form a double H under the heart, and the vas deferens (VD) arise from each side at the posterior edge of the double H. The main characteristic of the VD is the presence of a sphincter in the enlarged area of the distal end of the middle VD. The MVD here shows an increase in musculature of the wall as compared to the VD, which regulates the passage of the sperm cord to the distal VD (DVD) and thence to the thelycum of the female. The wall of the spermatophore is formed in the distal part of the proximal VD, which surrounds the unique sperm cord present in the VD. Isolated spermatophores are not observed in the VD. The sperm cord is pinched off during copulation by the musculature of the DVD. Then, a portion of the sperm cord is transferred from each VD to form the isolated spermatophores. The wall of the spematophores and the spermatozoa that are observed inside the thelycum have the same morphology as those observed in the VD.

  19. [out of scope].

    PubMed

    Becvárová, Martina; Becvár, Jindrich; Skoda, Jan

    2008-01-01

    Emil Weyr (1848-1894) was an important Bohemian mathematician. His scientific career was strongly influenced by his study tour in Italy in the years 1870-1871, above all by his contact with Luigi Cremona (1830-1903). After his return from Italy he was appointed Extraordinary Professor at the Bohemian Polytechnic Institute in Prague. In 1875 he became Ordinary Professor of mathematics at the university of Vienna. This paper gives a short survey of his life and work and contains extracts from his diary. A detailed description of his stay in Italy, his life and his scientific work is to be found in the monograph that we published in 2006 [J. Becvár, M. Becvárová, J. Skoda: "Emil Weyr a jeho pobyt v Itálii v roce 1870/71", Edition Dĕjiny matematiky, Band 28, Ceské vysoké ucení technické, Praha, 2006]. PMID:18693644

  20. Prevalence of high risk Tl-201 scintigraphic findings in patients with coronary artery disease: Relation to coronary anatomy and ECG stress test findings

    SciTech Connect

    Ryan, J.M.; Nygaard, T.W.; Gibson, R.S.; Gascho, J.A.; Watson, D.D.; Beller, G.A.

    1984-01-01

    The prevalence of a high risk exercise (Ex) Tl-201 (Tl) scintigram (scint) was determined in 295 consecutive patients (pts) with angiographic (angio) (>50% stenosis) coronary artery disease (CAD) and correlated with extent of CAD and Ex stress test findings. A high risk scint by quantitative criteria was defined as either: 1) a typical left main (LM) CAD pattern showing greater than or equal to 25% homogenous disease in Tl activity in septal and posterolateral walls; 2) a multivessel disease (MVD) pattern showing abnormal Tl uptake and/or washout in multiple vascular scan segments; 3) increased lung Tl uptake. The typical LMCAD pattern was observed in 6 of 43 pts (14%) with LMCAD compared to 2% of 53 pts with 3VD (p=0.03), 3% of 99 pts with 2VD (p=0.02) and 2% of 100 pts with 1VD (p-0.01). The MVD scint pattern was seen in 67% of pts with LMCAD compared to 49% (p=0.05) in 3VD pts, 41% (p=0.004) in 2VD pts and 24% (p=<0.0001) in 1VD pts. Prevalence of abnormal lung Tl was comparable in LMCAD (42%), 3VD (38%) and 2VD (34%) pts, but greater than observed in 1VD pts (26%; p=0.05). High risk ECG stress test was defined as 2 or more of: 1) >2.0 mm of ST decreasing; 2) greater than or equal to1.0 mm ST decreasing persisting >5 min post-EX; 3) ST decreasing at less than or equal to5 METS; 4) greater than or equal to10 mm Hg decreasing in Ex blood pressure. A high risk ECG stress test was observed in 58% of LMCAD pts compared to 32% of 3VD pts (p=0.009), 31% of 2VD pts (p=0.003) and 16% of 1VD pts (p<0.0001). Eighty-six % of LMCAD and 70% of 2 and 3VD pts had either a high risk Ex scint or stress test. Thus, EX Tl-201 scint appears useful in identifying high risk CAD pts.

  1. Transmyometrial versus very difficult transcervical embryo transfer: efficacy and safety.

    PubMed

    Khairy, Mohammed; Shah, Hany; Rajkhowa, Madhurima

    2016-05-01

    A difficult and traumatic embryo transfer can negatively impact on embryo implantation. This study retrospectively compared the outcomes of "very difficult transcervical embryo transfer" (vdTCET) versus transmyometrial embryo transfer (TMET) in a single centre over 10 years, reporting on 128 patients with vdTCET and 46 patients with TMET. The definition of vdTCET was a procedure rated by an experienced practitioner (with more than 100 transfers per year for >2 years) as very difficult and required two or more of the following: use of tenaculum, change of embryo transfer catheter and use of a stylet, reloading of the embryos or cancelling the procedure and freezing the embryo to transfer after cervical dilatation. The clinical pregnancy rates for TMET and vdTCET were 32.6% and 25%, respectively and the live birth rates were 26.1% and 16.4%, respectively. There was only one case of minor bleeding in the TMET group (2.2%). This study showed that TMET is a good alternative option in cases of vdTCET where it is impossible to achieve transcervical embryo transfer and may benefit cases with repeated failed cycles after vdTCET. Its superiority over vdTCET however could not be demonstrated. PMID:26968927

  2. Including screening in van der Waals corrected density functional theory calculations: the case of atoms and small molecules physisorbed on graphene.

    PubMed

    Silvestrelli, Pier Luigi; Ambrosetti, Alberto

    2014-03-28

    The Density Functional Theory (DFT)/van der Waals-Quantum Harmonic Oscillator-Wannier function (vdW-QHO-WF) method, recently developed to include the vdW interactions in approximated DFT by combining the quantum harmonic oscillator model with the maximally localized Wannier function technique, is applied to the cases of atoms and small molecules (X=Ar, CO, H2, H2O) weakly interacting with benzene and with the ideal planar graphene surface. Comparison is also presented with the results obtained by other DFT vdW-corrected schemes, including PBE+D, vdW-DF, vdW-DF2, rVV10, and by the simpler Local Density Approximation (LDA) and semilocal generalized gradient approximation approaches. While for the X-benzene systems all the considered vdW-corrected schemes perform reasonably well, it turns out that an accurate description of the X-graphene interaction requires a proper treatment of many-body contributions and of short-range screening effects, as demonstrated by adopting an improved version of the DFT/vdW-QHO-WF method. We also comment on the widespread attitude of relying on LDA to get a rough description of weakly interacting systems. PMID:24697424

  3. Effect of vitamin D3 on production of progesterone in porcine granulosa cells by regulation of steroidogenic enzymes.

    PubMed

    Hong, So-Hye; Lee, Jae-Eon; Kim, Hong Sung; Jung, Young-Jin; Hwang, DaeYoun; Lee, Jae Ho; Yang, Seung Yun; Kim, Seung-Chul; Cho, Seong-Keun; An, Beum-Soo

    2016-05-01

    1,25-dihydroxyvitamin D3 (VD3), an active form of Vitamin D, is photosynthesized in the skin of vertebrates in response to solar ultraviolet B radiation (UV-B). VD3 deficiency can cause health problems such as immune disease, metabolic disease, and bone disorders. It has also been demonstrated that VD3 is involved in reproductive functions. Female sex hormones such as estrogen and progesterone are biosynthesized mainly in ovarian granulosa cells as the ovarian follicle develops. The functions of sex hormones include regulation of the estrus cycle and puberty as well as maintenance of pregnancy in females. In this study, we isolated granulosa cells from porcine ovaries and cultured them for experiments. To examine the effects of VD3 on ovarian granulosa cells, the mRNA and protein levels of genes were analyzed by Real-time PCR and Western blotting assay. Production of progesterone from granulosa cells was also measured by ELISA assay. As a result, transcriptional and translational regulation of progesterone biosynthesis-related genes in granulosa cells was significantly altered by VD3. Furthermore, progesterone concentrations in porcine granulosa cell-cultured media decreased in response to VD3. These results show that VD3 was a strong regulator of sex steroid hormone production in porcine granulosa cells, suggesting that vitamin D deficiency may result in inappropriate sexual development of industrial animals and eventually economic loss. PMID:27533930

  4. Prospective study of vaginal dilator use adherence and efficacy following radiotherapy

    PubMed Central

    Law, Ethel; Kelvin, Joanne F.; Thom, Bridgette; Riedel, Elyn; Tom, Ashlyn; Carter, Jeanne; Alektiar, Kaled; Goodman, Karyn A.

    2016-01-01

    Background and purpose Vaginal stenosis (VS) after pelvic radiotherapy can impair long-term quality of life. We prospectively assessed adherence and efficacy of VD use as the primary and secondary objectives, respectively. Material and methods Women with gastrointestinal (n=63) and gynecologic (n=46) cancers self-reported use and VD size in monthly diaries for 12 months after radiotherapy. Adherence was measured as actual VD use out of recommended times over 12 months (3×/week × 52 weeks = 156). Results Among 109 participants, aged 28–81 years (median, 58 years), mean percent adherence over 12 months was 42% (95% confidence interval [CI], 36%–48%). Adherence was highest in the first quarter (56%), but fell to 25% by the fourth. Disease type, treatment sequence, and chemotherapy were predictors of adherence (all P<.05). Eighty-two percent maintained pre-RT VD size at 12 months; of 49% with decrease in VD size at 1 month post-RT, 71% returned to pre-RT VD size at 12 months. Disease type, younger age, and increased adherence at 6 months were associated with maintaining or returning to pre-RT size at 12 months (all P≤.05). Conclusions VD use is effective in minimizing VS, but adherence at 12 months was poor. Studies evaluating methods of improving adherence and determining the optimal frequency and duration of use are needed. PMID:26164775

  5. Influence of respiratory dead space on lung clearance index in preterm infants.

    PubMed

    Neumann, Roland P; Pillow, J Jane; Thamrin, Cindy; Frey, Urs; Schulzke, Sven M

    2016-03-01

    Lung clearance index (LCI), a marker of ventilation inhomogeneity derived from multiple breath washout (MBW), is used for clinical monitoring and as a key outcome of clinical trials in infants and children with cystic fibrosis. Utility of LCI is controversial in preterm infants with bronchopulmonary dysplasia (BPD) who tend to have high dead space to tidal volume ratio (VD/VT). We investigated the effect of VD/VT on LCI in a cohort of preterm infants with and without BPD and term healthy controls. We analyzed MBW data from 455 infants at a mean (SD) of 43.4 (3.5) w postmenstrual age. VD was estimated from the molar mass signal of an ultrasonic flowmeter (VD,MM). LCI was associated with VD,MM/VT (r(2)=0.13, p<0.001) but was not associated with BPD. Adjusting for VD,MM/VT did not reveal an association between LCI and BPD. We conclude that VD,MM/VT is a relevant factor when interpreting LCI in this population but the effect size of this association is moderate. PMID:26742626

  6. Vanadate-induced antiproliferative and apoptotic response in esophageal squamous carcinoma cell line EC109.

    PubMed

    Yang, Jie; Zhang, Zhuxia; Jiang, Shuyuan; Zhang, Ming; Lu, Jun; Huang, Lihua; Zhang, Tao; Gong, Kerui; Yan, Shaochun; Yang, Zhanjun; Shao, Guo

    2016-01-01

    Vanadate is a transition element that present in nature and was shown to be a nonspecific inhibitor of protein tyrosine phosphatases. It was reported that vanadium (Vd) compounds exhibit antitumor actions in several cancer cell lines. This study aimed to examine the antiproliferative and apoptotic actions of different concentrations of sodium vanadate (NaVd) (+5) in esophageal squamous carcinoma cell line EC109 by determining the protein expression levels of cyclin D1 and caspase-3 following incubation for various times from 15 min up to 4 h. In addition, cell proliferation of EC109 treated with different concentrations (NaVd) was also measured using the MTT assay at 4, 12, 24, and 48 h. The cell cycle of EC109 cells exposed to different concentrations of NaVd was detected using flow cytometry determination at 24 h. Data showed that NaVd greater than 100 µM significantly increased cyclin D1. In contrast, reduced caspase-3 protein expression levels occurred at 50 µM. Cellular proliferation was significantly decreased at 50uM. The cell cycle was arrested at S phase with 100 µM NaVd. Taken together, data indicate that NaVd produced concentration- and time-dependent antitumor actions in EC109 cell line. PMID:27599232

  7. Functional analysis of autophagy genes via Agrobacterium-mediated transformation in the vascular Wilt fungus Verticillium dahliae.

    PubMed

    Zhou, Lei; Zhao, Jun; Guo, Wangzhen; Zhang, Tianzhen

    2013-08-20

    Autophagy is a widely conserved intracellular process for degradation and recycling of proteins, organelles and cytoplasm in eukaryotic organisms and is now emerging as an important process in foliar infection by many plant pathogenic fungi. However, the role of autophagy in soil-borne fungal physiology and infection biology is poorly understood. Here, we report the establishment of an Agrobacterium tumefaciens-mediated transformation (ATMT) system and its application to investigate two autophagy genes, VdATG8 and VdATG12, by means of targeted gene replacement and complementation. Transformation of a cotton-infecting Verticillium dahliae strain Vd8 with a novel binary vector pCOM led to the production of 384 geneticin-resistant transformants per 1 × 10(6) conidia. V. dahliae mutants lacking either VdATG8 or VdATG12 exhibited reduced conidiation and impaired aerial hyphae production. Disease development on Arabidopsis plants was slightly delayed when inoculated with VdATG8 or VdATG12 gene deletion mutants, compared with the wild-type and gene complemented strains. Surprisingly, in vitro inoculation with unimpaired roots revealed that the abilities of root invasion were not affected in gene deletion mutants. These results indicate that autophagy is necessary for aerial hyphae development and plant colonization but not for root infection in V. dahliae.

  8. Exploration of virtual dimensionality in hyperspectral image analysis

    NASA Astrophysics Data System (ADS)

    Chang, Chein-I.

    2006-05-01

    Virtual dimensionality (VD) is a new concept which was developed to estimate the number of spectrally distinct signatures present in hyperspectral image data. Unlike intrinsic dimensionality which is mainly of theoretical interest, the VD is a very useful and practical notion. It is derived from the Neyman-Pearson detection theory. Unfortunately, its utility in hyperspectral data exploitation has yet to be explored. This paper presents several applications to which the VD is applied successfully. Since the VD is derived from a binary hypothesis testing problem for each spectral band, it can be used for band selection. When the test fails for a band, it indicates that there is a signal source in that particular band which must be selected. By the same token it can be further used for dimensionality reduction. For principal components analysis (PCA) or independent component analysis (ICA), the VD helps to determine the number of principal components or independent components are required for exploitation such as detection, classification, compression, etc. For unsupervised target detection and classification, the VD can be used to determine how many unwanted signal sources present in the image data so that they can be eliminated prior to detection and classification. For endmember extraction, the VD provides a good estimate of the number of endmembers needed to be extracted. All these applications are justified by experiments.

  9. Including screening in van der Waals corrected density functional theory calculations: the case of atoms and small molecules physisorbed on graphene.

    PubMed

    Silvestrelli, Pier Luigi; Ambrosetti, Alberto

    2014-03-28

    The Density Functional Theory (DFT)/van der Waals-Quantum Harmonic Oscillator-Wannier function (vdW-QHO-WF) method, recently developed to include the vdW interactions in approximated DFT by combining the quantum harmonic oscillator model with the maximally localized Wannier function technique, is applied to the cases of atoms and small molecules (X=Ar, CO, H2, H2O) weakly interacting with benzene and with the ideal planar graphene surface. Comparison is also presented with the results obtained by other DFT vdW-corrected schemes, including PBE+D, vdW-DF, vdW-DF2, rVV10, and by the simpler Local Density Approximation (LDA) and semilocal generalized gradient approximation approaches. While for the X-benzene systems all the considered vdW-corrected schemes perform reasonably well, it turns out that an accurate description of the X-graphene interaction requires a proper treatment of many-body contributions and of short-range screening effects, as demonstrated by adopting an improved version of the DFT/vdW-QHO-WF method. We also comment on the widespread attitude of relying on LDA to get a rough description of weakly interacting systems.

  10. Including screening in van der Waals corrected density functional theory calculations: The case of atoms and small molecules physisorbed on graphene

    SciTech Connect

    Silvestrelli, Pier Luigi; Ambrosetti, Alberto

    2014-03-28

    The Density Functional Theory (DFT)/van der Waals-Quantum Harmonic Oscillator-Wannier function (vdW-QHO-WF) method, recently developed to include the vdW interactions in approximated DFT by combining the quantum harmonic oscillator model with the maximally localized Wannier function technique, is applied to the cases of atoms and small molecules (X=Ar, CO, H{sub 2}, H{sub 2}O) weakly interacting with benzene and with the ideal planar graphene surface. Comparison is also presented with the results obtained by other DFT vdW-corrected schemes, including PBE+D, vdW-DF, vdW-DF2, rVV10, and by the simpler Local Density Approximation (LDA) and semilocal generalized gradient approximation approaches. While for the X-benzene systems all the considered vdW-corrected schemes perform reasonably well, it turns out that an accurate description of the X-graphene interaction requires a proper treatment of many-body contributions and of short-range screening effects, as demonstrated by adopting an improved version of the DFT/vdW-QHO-WF method. We also comment on the widespread attitude of relying on LDA to get a rough description of weakly interacting systems.

  11. Impact of vitamin D administration on immunogenicity of trivalent inactivated influenza vaccine in previously unvaccinated children.

    PubMed

    Principi, Nicola; Marchisio, Paola; Terranova, Leonardo; Zampiero, Alberto; Baggi, Elena; Daleno, Cristina; Tirelli, Silvia; Pelucchi, Claudio; Esposito, Susanna

    2013-05-01

    As vitamin D (VD) has a significant regulatory effect on innate and adaptive immunity, the aim of this prospective, randomized, single-blinded, placebo-controlled study was to measure the impact of VD administration on the immune response to trivalent influenza vaccination (TIV). A total of 116 children (61 males, 52.6%; mean age 3.0 ± 1.0 y) with a history of recurrent acute otitis media (AOM), who had not been previously vaccinated against influenza, were randomized to receive daily VD 1,000 IU or placebo by mouth for four months. All of them received two doses of TIV (Fluarix, GlaxoSmithKline Biologicals) one month apart, with the first dose administered when VD supplementation was started. There was no difference in seroconversion or seroprotection rates, or antibody titers, in relation to any of the three influenza vaccine antigens between the VD and placebo groups, independently of baseline and post-treatment VD levels. The safety profile was also similar in the two groups. These data indicate that the daily administration of VD 1,000 IU for four months from the time of the injection of the first dose of TIV does not significantly modify the antibody response evoked by influenza vaccine.

  12. Vitamin D Deficiency Promotes Liver Tumor Growth in Transforming Growth Factor-β/Smad3-Deficient Mice Through Wnt and Toll-like Receptor 7 Pathway Modulation

    PubMed Central

    Chen, Jian; Katz, Lior H.; Muñoz, Nina M.; Gu, Shoujun; Shin, Ji-hyun; Jogunoori, Wilma S.; Lee, Mi-Hye; Belkin, Mitchell D.; Kim, Sang-Bae; White, Jon C.; Andricovich, Jaclyn; Tzatsos, Alexandros; Li, Shulin; Kim, Sang Soo; Shetty, Kirti; Mishra, Bibhuti; Rashid, Asif; Lee, Ju-Seog; Mishra, Lopa

    2016-01-01

    Disruption of the TGF-β pathway is associated with liver fibrosis and suppression of liver tumorigenesis, conditions associated with low Vitamin D (VD) levels. However, potential contributions of VD to liver tumor progression in the context of TGF-β signaling remain unexplored. Our analyses of VD deprivation (VDD) in in vivo models of liver tumor formation revealed striking three-fold increases in tumor burden in Smad3+/− mice, with a three-fold increase in TLR7 expression compared to controls. ChIP and transcriptional assays confirm Smad3 binding at two TLR7 promoter SBE sites. Molecular interactions between TGF-β pathway and VDD were validated clinically, where an absence of VD supplementation was associated with low TGF-β pathway member expression levels and β-catenin activation in fibrotic/cirrhotic human liver tissues. Subsequent supplementing VD led to restoration of TGF-β member expression with lower β-catenin levels. Bioinformatics analysis provides positive supportive correlation between somatic mutations for VD-related genes and the TGF-β pathway. We conclude that VDD promotes tumor growth in the context of Smad3 disruption, potentially through regulation of TLR7 expression and β-catenin activation. VD could therefore be a strong candidate for liver cancer prevention in the context of aberrant Smad3 signaling. PMID:27456065

  13. Effect of vitamin D3 on production of progesterone in porcine granulosa cells by regulation of steroidogenic enzymes

    PubMed Central

    Hong, So-Hye; Lee, Jae-Eon; Kim, Hong Sung; Jung, Young-Jin; Hwang, DaeYoun; Lee, Jae Ho; Yang, Seung Yun; Kim, Seung-Chul; Cho, Seong-Keun; An, Beum-Soo

    2016-01-01

    Abstract 1,25-dihydroxyvitamin D3 (VD3), an active form of Vitamin D, is photosynthesized in the skin of vertebrates in response to solar ultraviolet B radiation (UV-B). VD3 deficiency can cause health problems such as immune disease, metabolic disease, and bone disorders. It has also been demonstrated that VD3 is involved in reproductive functions. Female sex hormones such as estrogen and progesterone are biosynthesized mainly in ovarian granulosa cells as the ovarian follicle develops. The functions of sex hormones include regulation of the estrus cycle and puberty as well as maintenance of pregnancy in females. In this study, we isolated granulosa cells from porcine ovaries and cultured them for experiments. To examine the effects of VD3 on ovarian granulosa cells, the mRNA and protein levels of genes were analyzed by Real-time PCR and Western blotting assay. Production of progesterone from granulosa cells was also measured by ELISA assay. As a result, transcriptional and translational regulation of progesterone biosynthesis-related genes in granulosa cells was significantly altered by VD3. Furthermore, progesterone concentrations in porcine granulosa cell-cultured media decreased in response to VD3. These results show that VD3 was a strong regulator of sex steroid hormone production in porcine granulosa cells, suggesting that vitamin D deficiency may result in inappropriate sexual development of industrial animals and eventually economic loss. PMID:27533930

  14. Hippocampal diffusion tensor imaging microstructural changes in vascular dementia.

    PubMed

    Ostojic, Jelena; Kozic, Dusko; Pavlovic, Aleksandra; Semnic, Marija; Todorovic, Aleksandar; Petrovic, Kosta; Covickovic-Sternic, Nadezda

    2015-12-01

    To explore microstructural integrity of hippocampus in vascular dementia (VD) using DTI. Twenty-five individuals with VD, without magnetic resonance imaging (MRI) evidence of gray matter pathology, and 25 matched healthy control (HC) individuals underwent a 3T MRI protocol including T2, FLAIR, and PD in the axial plane, 3D whole-brain T1-weighted with an isotropic resolution of 1 mm, and DTI acquired using 64 diffusion sensitizing directions, b value of 1,500 s/mm(2), 65 axial slices, isotropic resolution of 1.8 mm. Images were processed to obtain indices of microstructural variations of bilateral hippocampi. Mean diffusivity (MD) in the hippocampus of patients with VD was significantly increased (p < 0.05) bilaterally with respect to that of the group of HC examinees. In VD group left hippocampal MD (10(-6 )× mm(2)/s) was 833.4 ± 92.8; in HC group left MD was 699.8 ± 56. In VD group, right hippocampal MD was 859.1 ± 69.8; in HC group right MD was 730.4 ± 40.2. No group differences were found in hippocampal FA. DTI shows microstructural hippocampal damage in VD in patients with normal appearing gray matter structures on conventional MRI, indicating the need for further research on the link between VD and AD. PMID:25555903

  15. Synergistic Effect of Vaginal Trauma and Ovariectomy in a Murine Model of Stress Urinary Incontinence: Upregulation of Urethral Nitric Oxide Synthases and Estrogen Receptors

    PubMed Central

    Chen, Huey-Yi; Chen, Wen-Chi; Lin, Yu-Ning

    2014-01-01

    The molecular mechanisms underlying stress urinary incontinence (SUI) are unclear. We aimed to evaluate the molecular alterations in mice urethras following vaginal trauma and ovariectomy (OVX). Twenty-four virgin female mice were equally distributed into four groups: noninstrumented control; vaginal distension (VD) group; OVX group; and VD + OVX group. Changes in leak point pressures (LPPs), genital tract morphology, body weight gain, plasma 17β-estradiol level and expressions of neuronal nitric oxide synthase (nNOS), induced nitric oxide synthase (iNOS), and estrogen receptors (ERs—ERα and ERβ) were analyzed. Three weeks after VD, the four groups differed significantly in genital size and body weight gain. Compared with the control group, the plasma estradiol levels were significantly decreased in the OVX and VD + OVX groups, and LPPs were significantly decreased in all three groups. nNOS, iNOS, and ERα expressions in the urethra were significantly increased in the VD and VD + OVX groups, whereas ERβ expression was significantly increased only in the VD + OVX group. These results show that SUI following vaginal trauma and OVX involves urethral upregulations of nNOS, iNOS, and ERs, suggesting that NO- and ER-mediated signaling might play a role in the synergistic effect of birth trauma and OVX-related SUI pathogenesis. PMID:25258476

  16. C–C motif ligand 11 reduction in CLL patients serum after vitamin D supplementation

    PubMed Central

    Kubeczko, Marcin; Nowara, Elżbieta; Karwasiecka, Dobromiła; Siewior, Grażyna; Czajka-Francuz, Paulina; Chudek, Jerzy; Wojnar, Jerzy

    2016-01-01

    Background: Vitamin D (VD) deficiency results in a worse prognosis in patients with chronic lymphocytic leukemia (CLL) and may affect the production of cytokines. Nonetheless, there is the lack of studies dealing with VD supplementation and its impact on chemokines in CLL patients. Aim: The primary endpoint of our interventional study was to evaluate the effect of cholecalciferol supplementation on serum chemokines levels in CLL patients. Materials and methods: Eighteen subjects with CLL were enrolled for the study. Six-month-long cholecalciferol supplementation was performed in CLL patients with serum 25-OH-D3 levels below 30 ng/ml. Cytokines levels were assessed at the beginning of the study and after 6 months. Baseline measurements of cytokines were compared to those in apparently healthy controls. Results: Increased levels of CCL2, CCL3, CCL4, CXCL8, CXCL10, TNFα, bFGF, G-CSF, and VEGF were found in CLL patients in comparison with the healthy controls. In the course of the VD supplementation a decrease in serum levels of chemokines CCL11, CCL3, and cytokine PDGF-BB was observed. The decrease of CCL11 was found in CLL patients on VD supplementation solely, whereas the decrease of CCL3 and PDGF-BB was observed in CLL subjects on both chemotherapy and VD supplementation. Conclusion: The VD supplementation may exert beneficial effect on chemokines levels in CLL patients with VD deficiency. PMID:26902783

  17. Stress and vitamin D: altered vitamin D metabolism in both the hippocampus and myocardium of chronic unpredictable mild stress exposed rats.

    PubMed

    Jiang, Pei; Zhang, Wen-Yuan; Li, Huan-De; Cai, Hua-Lin; Liu, Yi-Ping; Chen, Lin-Yao

    2013-10-01

    Exposure to stressful life events is associated with the onset of major depression and increases the risk of cardiac morbidity and mortality. While recent evidence has indicated the existence of an interrelationship between local vitamin D (VD) metabolism and many aspects of human physiology including brain and heart function, much is still unknown concerning the biological link between VD signaling and stress-induced depressive behavior and cardiac dysfunction. In the present study, we observed the VD intracrine system in the hippocampus and myocardium of chronic unpredictable mild stress (CUMS) exposed rats. After 4 weeks of CUMS procedure, rats were induced to a depressive-like state and the cytochromes P450 enzymes involved in VD activating and catabolizing (CYP27B1 and CYP24A1 respectively) and VD receptor (VDR) were assessed by real time RT-PCR and western blot in the hippocampus, myocardium and kidney. In the hippocampus of depressed rats, CYP27B1, CYP24A1 and VDR expression were significantly increased and the local status of 1,25-dihydroxyvitamin D (1,25(OH)2D) was higher compared with controls. Furthermore, hippocampal mRNA levels of VD target genes (calbindin-d28k, neurotrophin-3) and RXRα (heterodimeric partner of VDR) were upregulated in response to chronic stress. Similar to the hippocampus, CUMS also induced CYP27B1/CYP24A1/VDR expression in the myocardium. However, renal metabolism of VD and serum1,25(OH)2D status were unchanged. Meanwhile, sertraline treatment could partly normalize the stress-induced alterations of VD metabolism. In conclusion, this study firstly showed a co-elevated expression of CYP27B1/CYP24A1/VDR in both the hippocampus and myocardium of CUMS rats, which suggests VD signaling may be involved in the compensatory mechanism that protect from stress-induced deteriorating effects on the brain and heart.

  18. Stem Cell Homing Factor, CCL7, Expression in Mouse Models of Stress Urinary Incontinence

    PubMed Central

    Hijaz, Adonis K.; Grimberg, Kerry O.; Tao, Mingfang; Schmotzer, Brian; Sadeghi, Zhina; Lin, Yi-Hao; Kavran, Michael; Ozer, Ahmet; Xiao, Nan; Daneshgari, Firouz

    2014-01-01

    Objectives Animal models of vaginal distention (VD) have demonstrated increased expression of chemokine (C-C motif) ligand 7 (CCL7). In this study, we investigated the expression of CCL7 in mice models of simulated birth trauma-induced urinary incontinence utilizing VD and pudendal nerve transection (PNT). Methods Forty-nine mice were divided into 6 groups: VD, sham VD, PNT, sham PNT anesthesia, and age-matched controls. The urethra, vagina, and rectum were harvested for the expression of CCL7 immediately or 24 hours after assigned procedure. Venous sampling for quantification of serum CCL7 was also performed. An ANOVA model was used to compare the relative expression of CCL7 in each group. Results Urethral CCL7 expression in the VD group was significantly higher than control group after 24 hours (p<0.01). There was no difference in the urethral CCL7 expression in PNT, sham PNT, sham VD or anesthesia groups compared with controls. No statistically significant difference was noted in the vaginal and rectal expression of CCL7 between any of the groups except for sham PNT. Statistically significant differences were noted in the serum CCL7 expression in VD, PNT and sham PNT (p<0.01 in all) groups after 24 hours compared with the control group. Conclusions This study demonstrates over-expression of urethral CCL7 after VD but not PNT. This suggests that nerve injury does not contribute to the CCL7 over-expression. The over-expression of CCL7 in the serum of mice after VD suggests a translational potential where CCL7 measurement could be used as a surrogate for injury after delivery. PMID:24165450

  19. 1α,25-dihydroxyvitamin D3 modulates the hair-inductive capacity of dermal papilla cells: therapeutic potential for hair regeneration.

    PubMed

    Aoi, Noriyuki; Inoue, Keita; Chikanishi, Toshihiro; Fujiki, Ryoji; Yamamoto, Hanako; Kato, Harunosuke; Eto, Hitomi; Doi, Kentaro; Itami, Satoshi; Kato, Shigeaki; Yoshimura, Kotaro

    2012-08-01

    Dermal papilla cells (DPCs) have the potential to induce differentiation of epithelial stem cells into hair, and Wnt signaling is deeply involved in the initiation process. The functional limitation of expanded adult DPCs has been a difficult challenge for cell-based hair regrowth therapy. We previously reported that 1α,25-dihydroxyvitamin D(3) (VD(3)) upregulates expression of transforming growth factor (TGF)-β2 and alkaline phosphatase (ALP) activity, both features of hair-inducing human DPCs (hDPCs). In this study, we further examined the effects and signaling pathways associated with VD(3) actions on DPCs. VD(3) suppressed hDPC proliferation in a dose-dependent, noncytotoxic manner. Among the Wnt-related genes investigated, Wnt10b expression was significantly upregulated by VD(3) in hDPCs. Wnt10b upregulation, as well as upregulation of ALPL (ALP, liver/bone/kidney) and TGF-β2, by VD(3) was specific in hDPCs and not detected in human dermal fibroblasts. Screening of paracrine or endocrine factors in the skin indicated that all-trans retinoic acid (atRA) upregulated Wnt10b gene expression, although synergistic upregulation (combined atRA and VD(3)) was not seen. RNA interference with vitamin D receptor (VDR) revealed that VD(3) upregulation of Wnt10b, ALPL, and TGF-β2 was mediated through the genomic VDR pathway. In a rat model of de novo hair regeneration by murine DPC transplantation, pretreatment with VD(3) significantly enhanced hair folliculogenesis. Specifically, a greater number of outgrowing hair shafts and higher maturation of regenerated follicles were observed. Together, these data suggest that VD(3) may promote functional differentiation of DPCs and be useful in preserving the hair follicle-inductive capacity of cultured DPCs for hair regeneration therapies.

  20. Autophagy enhancement contributes to the synergistic effect of vitamin D in temozolomide-based glioblastoma chemotherapy

    PubMed Central

    BAK, DONG-HO; KANG, SEONG HEE; CHOI, DU RI; GIL, MI NA; YU, KWANG SIK; JEONG, JI HEUN; LEE, NAM-SEOB; LEE, JE-HUN; JEONG, YOUNG-GIL; KIM, DONG KWAN; KIM, DO-KYUNG; KIM, JWA-JIN; HAN, SEUNG-YUN

    2016-01-01

    Temozolomide (TMZ), an alkylating agent, is recommended as the initial treatment for high-grade glioblastoma. TMZ is widely used, but its short half-life and the frequency of tumor resistance limit its therapeutic efficacy. In the present study, the anticancer effect of vitamin D (VD) combined with TMZ upon glioblastoma was determined, and the underlying mechanism of this effect was identified. Through cell viability, clonogenic and wound healing assays, the current study demonstrated that treatment of a C6 glioblastoma cell line with TMZ and VD resulted in significantly increased in vitro antitumor effects compared with either VD or TMZ alone. Autophagy, hypothesized to be the dominant mechanism underlying TMZ-based tumor cell death, was maximally activated in TMZ and VD co-treated C6 cells. This was demonstrated by ultrastructural observations of autophagosomes, increased size and number of microtubule-associated protein 1 light chain 3 (LC3) puncta and increased conversion of LC3-I to LC3-II. However, the extent of apoptosis was not significantly different between cells treated with TMZ and VD and those treated with TMZ alone. Addition of the autophagy inhibitor 3-methyladenine markedly inhibited the anticancer effect of TMZ and VD treatment, indicating that the chemosensitizing effect of VD in TMZ-based glioblastoma therapy is generated through enhancement of cytotoxic autophagy. TMZ and VD co-treatment also significantly inhibited tumor progression and prolonged survival duration in rat glioblastoma orthotopic xenograft models when compared with TMZ treatment alone. These in vivo results are concordant with the aforementioned in vitro results, together revealing that the combined use of TMZ and VD exerts synergistic antitumor effects on rat models of glioblastoma and may represent an effective therapeutic strategy. PMID:27313664

  1. Novel Infection System of Recombinant BmBDV DNA into BmN Cells of Silkworm, Bombyx mori.

    PubMed

    Guo, Rui; Cao, Guangli; Zhu, Yuexiong; Kumar, Dhiraj; Xue, Renyu; Lu, Yahong; Hu, Xiaolong; Gong, Chengliang

    2016-10-01

    Bombyx mori bidensovirus (BmBDV) was previously termed as Bombyx mori densovirus type 2 and later it was reclassified in the new genus bidensovirus of the new family Bidnaviridae. The genome of BmBDV Zhenjiang isolate (BmBDV-Z) consists of two non-homologous single-stranded linear DNA molecules VD1 and VD2 which are encapsidated into separate virion. To investigate the infectivity of BmBDV DNA, recombinant plasmids pGEM-VD1 inserted with VD1 genome were transfected into the BmN cells of silkworm. Structural proteins of BmBDV were detected with Western blot and immunofluorescence assay, which indicates pGEM-VD1 replicated in the transfected BmN cells and viral proteins were also expressed. Through TEM observation, we identified about 20 nm BmBDV-like viral particles, which confirmed that BmBDV can be generated after transfection. Subsequently, a recombinant baculovirus BmBac-VD1 inserted with VD1 genome was constructed. Results of Western blot and immunofluorescence assay indicated that viral structural proteins of BmBDV were expressed in the BmBac-VD1-infected cells. Baculiform and spherical virions were also observed in infected cells by TEM, and two kinds of virions were separated. However, results of molecular biological detection revealed that infectious sequence from BmBac-VD1 was packaged within spherical virion. Therefore, we suggested that vector inserted with BmBDV genomic DNA showed infectivity, and BmBDV-like viral particles packaging recombinant DNA can be produced in the cultured BmN cells. Outcome of our current research provided not only a new method of infection to explore the gene function of BmBDV in vitro but also a protocol to facilitate development of more effective new-type pesticides. PMID:27447797

  2. Sun Exposure and Vitamin D Supplementation in Relation to Vitamin D Status of Breastfeeding Mothers and Infants in the Global Exploration of Human Milk Study

    PubMed Central

    Dawodu, Adekunle; Davidson, Barbara; Woo, Jessica G.; Peng, Yong-Mei; Ruiz-Palacios, Guillermo M.; Guerrero, Maria de Lourdes; Morrow, Ardythe L.

    2015-01-01

    Although vitamin D (vD) deficiency is common in breastfed infants and their mothers during pregnancy and lactation, a standardized global comparison is lacking. We studied the prevalence and risk factors for vD deficiency using a standardized protocol in a cohort of breastfeeding mother-infant pairs, enrolled in the Global Exploration of Human Milk Study, designed to examine longitudinally the effect of environment, diet and culture. Mothers planned to provide breast milk for at least three months post-partum and were enrolled at four weeks postpartum in Shanghai, China (n = 112), Cincinnati, Ohio (n = 119), and Mexico City, Mexico (n = 113). Maternal serum 25(OH)D was measured by radioimmunoassay (<50 nmol/L was categorized as deficient). Serum 25(OH)D was measured in a subset of infants (35 Shanghai, 47 Cincinnati and 45 Mexico City) seen at 26 weeks of age during fall and winter seasons. Data collected prospectively included vD supplementation, season and sun index (sun exposure × body surface area exposed while outdoors). Differences and factors associated with vD deficiency were evaluated using appropriate statistical analysis. vD deficiency in order of magnitude was identified in 62%, 52% and 17% of Mexican, Shanghai and Cincinnati mothers, respectively (p < 0.001). In regression analysis, vD supplementation (p < 0.01), obesity (p = 0.03), season (p = 0.001) and sites (p < 0.001) predicted maternal vD status. vD deficiency in order of  magnitude was found in 62%, 28%, and 6% of Mexican, Cincinnati and Shanghai infants, respectively (p < 0.001). Season (p = 0.022), adding formula feeding (p < 0.001) and a higher sun index (p = 0.085) predicted higher infant vD status. vD deficiency appears to be a global problem in mothers and infants, though the prevalence in diverse populations may depend upon sun exposure behaviors and vD supplementation. Greater attention to maternal and infant vD status starting during pregnancy is warranted worldwide. PMID:25665158

  3. Interlayer coupling effects on Schottky barrier in the arsenene-graphene van der Waals heterostructures

    SciTech Connect

    Xia, Congxin Xue, Bin; Wang, Tianxing; Peng, Yuting; Jia, Yu

    2015-11-09

    The electronic characteristics of arsenene-graphene van der Waals (vdW) heterostructures are studied by using first-principles methods. The results show that a linear Dirac-like dispersion relation around the Fermi level can be quite well preserved in the vdW heterostructures. Moreover, the p-type Schottky barrier (0.18 eV) to n-type Schottky barrier (0.31 eV) transition occurs when the interlayer distance increases from 2.8 to 4.5 Å, which indicates that the Schottky barrier can be tuned effectively by the interlayer distance in the vdW heterostructures.

  4. Visualization of Hair Bulbs through the Scalp: A Trichoscopic Feature of Erosive Pustular Dermatitis of the Scalp.

    PubMed

    Starace, Michela; Patrizi, Annalisa; Piraccini, Bianca Maria

    2016-01-01

    Erosive pustular dermatitis of the scalp (EPDS) typically affects elderly people with scarring alopecia. Videodermoscopy (VD) of the scalp has never been assessed in the diagnosis of EPDS. To evaluate the trichoscopy features of EPDS, we carried out a retrospective analysis of VD images obtained in the scalp of ten patients who affected by EPDS and were compared with those obtained from a series of thirty patients who affected by other type of scarring alopecia. The most specific VD feature was thus represented by evident hair bulb in the scarring scalp, observed in all patients. PMID:27601866

  5. Effect of the supplementation of dietary rich phytoestrogens in altering the vitamin D levels in diet induced osteoporotic rat model.

    PubMed

    Chennaiah, S; Vijayalakshmi, V; Suresh, C

    2010-07-01

    Plant-derived estrogen-like compounds such as isoflavones (IF) especially daidzein and genistein are said to be preserving the bone in the osteoporotic conditions. However, it is not known whether a combination of IF and calcium (Ca) supplementation attenuates losses in bone mass and prevents the loss of vitamin D (VD). The present study addresses the role of phytoestrogens (PE) and Ca supplementation in low Ca and low VD diet induced osteoporosis (OSP). Cowpea (CP) which has high amount of the IF was selected to study its effect on diet induced osteoporotic conditions. Female weanling WNIN rats (total of 68) were divided into five groups and fed for five weeks on semisynthetic diet with low Ca (0.15%) and low VD (0.1IU/day/rat) in combination with low (10 mg/kg) or high (25 mg/kg) concentrations of PEs derived from CPIF. The study groups are: (I) normal Ca(0.47%) and normal VD (25IU/day/rat), (II) low Ca+low VD, (III) low Ca+low VD+low CPIF (10 mg/kg diet), (IV) low Ca+low VD+high CPIF (25 mg/kg diet) and (V) low Ca+low VD+17-(-estradiol (3.2 mg/kg diet). After the development of OSP the group II was subgrouped into: (SG I) continued on low Ca+VD, (SG II) low CPIF, (SG III) high CPIF, (SG IV) 17-beta-estradiol and (SG V) normal Ca and VD. Serum 25-VD levels were in the range of 14-38 ng/ml in groups I, III, IV and V, where as the values were very low in the group II (5.8 ng/ml). These were partially reversed upon supplementation of CPIF. The results correlated with altered Ca levels, body weight, bone mineral density and content and other related biochemical parameters. The paper further explains the possibility of protective and therapeutic role of VD in the presence of CPIF in osteoporotic health manifestations. PMID:20362669

  6. Visualization of Hair Bulbs through the Scalp: A Trichoscopic Feature of Erosive Pustular Dermatitis of the Scalp

    PubMed Central

    Starace, Michela; Patrizi, Annalisa; Piraccini, Bianca Maria

    2016-01-01

    Erosive pustular dermatitis of the scalp (EPDS) typically affects elderly people with scarring alopecia. Videodermoscopy (VD) of the scalp has never been assessed in the diagnosis of EPDS. To evaluate the trichoscopy features of EPDS, we carried out a retrospective analysis of VD images obtained in the scalp of ten patients who affected by EPDS and were compared with those obtained from a series of thirty patients who affected by other type of scarring alopecia. The most specific VD feature was thus represented by evident hair bulb in the scarring scalp, observed in all patients.

  7. The single epsin homolog in Giardia lamblia localizes to the ventral disk of trophozoites and is not associated with clathrin membrane coats.

    PubMed

    Ebneter, Jacqueline A; Hehl, Adrian B

    2014-10-01

    Epsins serve as recruitment platforms for clathrin membrane coat protein components and induce membrane curvature via their N-terminal homology (ENTH) domain. Unexpectedly, the single ENTH domain protein, a putative epsinR homolog (Glepsin), in the diverged protozoan parasite Giardia lamblia, localizes exclusively to the specialized attachment organelle, the ventral disk (VD). Glepsin binds both to phosphatidylinositol (3,4,5)-trisphosphate phospholipids and the VD cytoskeleton, but lacks canonical domains for interaction with clathrin coat components. This suggests reassignment of giardial epsin function from membrane trafficking to a structural role in linking the plasma membrane to the highly specialized VD during evolution of this genus. PMID:25286382

  8. Involvement of dopamine D1 receptors of the hippocampal dentate gyrus in spatial learning and memory deficits in a rat model of vascular dementia.

    PubMed

    Wan, P; Wang, S; Zhang, Y; Lv, J; Jin, Q H

    2014-09-01

    We investigated the involvement of dopamine (DA) and its D1 receptors of the hippocampal dentate gyrus (DG) in spatial learning and memory deficits in a rat model of vascular dementia (VD) established by permanent bilateral carotid occlusion. Spatial learning and memory abilities of rats were measured by Morris water maze, and extracellular concentrations of DA in the DG were determined by in vivo microdialysis. The DA concentrations in the DG decreased in the VD rats compared with sham-operated group. Microinjection of SFK38393 (D1 receptor agonist) into the DG attenuates spatial learning and memory deficits in the VD rats. PMID:25272945

  9. Conduction Mechanisms in CVD-Grown Monolayer MoS2 Transistors: From Variable-Range Hopping to Velocity Saturation.

    PubMed

    He, G; Ghosh, K; Singisetti, U; Ramamoorthy, H; Somphonsane, R; Bohra, G; Matsunaga, M; Higuchi, A; Aoki, N; Najmaei, S; Gong, Y; Zhang, X; Vajtai, R; Ajayan, P M; Bird, J P

    2015-08-12

    We fabricate transistors from chemical vapor deposition-grown monolayer MoS2 crystals and demonstrate excellent current saturation at large drain voltages (Vd). The low-field characteristics of these devices indicate that the electron mobility is likely limited by scattering from charged impurities. The current-voltage characteristics exhibit variable range hopping at low Vd and evidence of velocity saturation at higher Vd. This work confirms the excellent potential of MoS2 as a possible channel-replacement material and highlights the role of multiple transport phenomena in governing its transistor action.

  10. Hot carrier stressing damage in N-channel HEXFETs

    NASA Astrophysics Data System (ADS)

    Bendada, E.; Raïs, K.

    A method for device characterization is experimented to qualify hot-carrier stressing effects. The degradation of physical parameters of the body-drain junction of power HEXFETs is presented for applied stress conditions (VG=VD/2, VG=VD). A large increase of the series resistance, of the ideality factor and of the reverse recombination current are shown to be related to stress time, and are significant in the region of maximum substrates current (VG=VD/2). It is demonstrated that these effects are mainly caused by the generation of interface traps.

  11. Electric field modulation of Schottky barrier height in graphene/MoSe{sub 2} van der Waals heterointerface

    SciTech Connect

    Sata, Yohta; Moriya, Rai E-mail: tmachida@iis.u-tokyo.ac.jp; Morikawa, Sei; Yabuki, Naoto; Masubuchi, Satoru; Machida, Tomoki E-mail: tmachida@iis.u-tokyo.ac.jp

    2015-07-13

    We demonstrate a vertical field-effect transistor based on a graphene/MoSe{sub 2} van der Waals (vdW) heterostructure. The vdW interface between the graphene and MoSe{sub 2} exhibits a Schottky barrier with an ideality factor of around 1.3, suggesting a high-quality interface. Owing to the low density of states in graphene, the position of the Fermi level in the graphene can be strongly modulated by an external electric field. Therefore, the Schottky barrier height at the graphene/MoSe{sub 2} vdW interface is also modulated. We demonstrate a large current ON-OFF ratio of 10{sup 5}. These results point to the potential high performance of the graphene/MoSe{sub 2} vdW heterostructure for electronics applications.

  12. Virtual Dimensionality Estimation in Hyperspectral Imagery Based on Unsupervised Feature Selection

    NASA Astrophysics Data System (ADS)

    Ghamary Asl, M.; Mojaradi, B.

    2016-06-01

    Virtual Dimensionality (VD) is a concept developed to estimate the number of distinct spectral signatures in hyperspectral imagery. Intuitively, detecting the number of spectrally distinct signatures depends on determining the number of distinct bands of the data. Considering this idea, the current paper aims at estimating the VD based on finding independent bands in the image partition space. Eventually, the number of independent selected bands is accepted as the VD estimate. The proposed method is automatic and distribution-free. In addition, no tuning parameters and noise estimation processes are needed. This method is compared with three well-known VD estimation methods using synthetic and real datasets. Experimental results show high speed and reliability in the performance of the proposed method.

  13. Expansion of alien gammarids in the Vistula Lagoon and the Vistula Delta (Poland).

    PubMed

    Dobrzycka-Krahel, Aldona; Tarała, Anna; Chabowska, Anna

    2013-06-01

    Amphipod crustaceans belong to the most successful invaders of aquatic environments. The work provides information concerning the spatial and temporal scales of expansion of four alien gammarid amphipods (three of them of Ponto-Caspian and one of North American origin): Pontogammarus robustoides (G.O. Sars, 1894), Obesogammarus crassus (G.O. Sars, 1894), Dikerogammarus haemobaphes (Eichwald, 1841), and Gammarus tigrinus Sexton, 1939 in the Vistula Lagoon (VL) and the Vistula Delta (VD) in 2008-2010. The mean abundance of these gammarids in nearshore zones was 382 ind m(-2) in VL and 89 ind m(-2) in VD. Their mean biomasses were likewise greater in VL (0.91 g m(-2)) than in VD (0.49 g m(-2)). G. tigrinus was the most dominant species in both nearshore zones of VL and VD and attained the highest frequency in these areas. The study gives evidence of total extinction of native gammarid species.

  14. Bis(4-nitraminofurazanyl-3-azoxy)azofurazan and Derivatives: 1,2,5-Oxadiazole Structures and High-Performance Energetic Materials.

    PubMed

    Liu, Yuji; Zhang, Jiaheng; Wang, Kangcai; Li, Jinshan; Zhang, Qinghua; Shreeve, Jean'ne M

    2016-09-12

    Bis(4-nitraminofurazanyl-3-azoxy)azofurazan (1) and ten of its energetic salts were prepared and fully characterized. Computational analysis based on isochemical shielding surface and trigger bond dissociation enthalpy provide a better understanding of the thermal stabilities for nitramine-furazans. These energetic compounds exhibit good densities, high heats of formation, and excellent detonation velocity and pressure. Some representative compounds, for example, 1 (vD : 9541 m s(-1) ; P: 40.5 GPa), and 4 (vD : 9256 m s(-1) ; P: 38.0 GPa) exhibit excellent detonation performances, which are comparable with current high explosives such as RDX (vD : 8724 m s(-1) ; P: 35.2 GPa) and HMX (vD : 9059 m s(-1) ; P: 39.2 GPa).

  15. Bis(4-nitraminofurazanyl-3-azoxy)azofurazan and Derivatives: 1,2,5-Oxadiazole Structures and High-Performance Energetic Materials.

    PubMed

    Liu, Yuji; Zhang, Jiaheng; Wang, Kangcai; Li, Jinshan; Zhang, Qinghua; Shreeve, Jean'ne M

    2016-09-12

    Bis(4-nitraminofurazanyl-3-azoxy)azofurazan (1) and ten of its energetic salts were prepared and fully characterized. Computational analysis based on isochemical shielding surface and trigger bond dissociation enthalpy provide a better understanding of the thermal stabilities for nitramine-furazans. These energetic compounds exhibit good densities, high heats of formation, and excellent detonation velocity and pressure. Some representative compounds, for example, 1 (vD : 9541 m s(-1) ; P: 40.5 GPa), and 4 (vD : 9256 m s(-1) ; P: 38.0 GPa) exhibit excellent detonation performances, which are comparable with current high explosives such as RDX (vD : 8724 m s(-1) ; P: 35.2 GPa) and HMX (vD : 9059 m s(-1) ; P: 39.2 GPa). PMID:27511132

  16. Genetics Home Reference: Bietti crystalline dystrophy

    MedlinePlus

    ... on PubMed Central Mansour AM, Uwaydat SH, Chan CC. Long-term follow-up in Bietti crystalline dystrophy. ... VD, Zhang J, Gesualdo C, Corte MD, Chan CC, Fielding Hejtmancik J, Simonelli F. An atypical form ...

  17. Role for electrical synapses in shaping the output of coupled peptidergic neurons from Lymnaea.

    PubMed

    Beekharry, Christopher C; Zhu, Guan Z; Magoski, Neil S

    2015-04-01

    Electrically coupled neurons communicate through channel assemblies called gap junctions, which mediate the transfer of current from one cell to another. Electrical synapses ensure spike synchronization and reliable transmission, which influences bursting patterns and firing frequency. The present study concerns an electrically coupled two-neuron network in the gastropod mollusc, Lymnaea stagnalis. The neurons, designated Visceral Dorsal 1 (VD1) and Right Parietal Dorsal 2 (RPD2), are peptidergic, innervate aspects of the cardio-respiratory system, and show strong coupling, such that they fire synchronously. Using dual sharp-electrode current-clamp recording and morphological staining in isolated brain preparations, the hypothesis that the electrical synapse is necessary for accurate network output was tested. We found that both cells make extensive projections within and out of the brain, including across the visceral-parietal connective, which links VD1 and RPD2. Cutting this connective uncoupled the neurons and disrupted the firing rate and pattern of RPD2 more than VD1, consistent with VD1 being the master and RPD2 the follower. The electrical synapse was inhibited by select gap junction blockers, with niflumic acid and 5-nitro-2-(3-phenylpropylamino) benzoic acid decreasing the VD1→RPD2 and RPD2→VD1 coupling coefficients, whereas carbenoxolone, α-glycyrrhetinic acid, meclofenamic acid, and quinine were ineffective. There was little-to-no impact on VD1↔RPD2 firing synchrony or frequency when coupling was reduced pharmacologically. However, in the presence of gap junction blockers, suppressing the activity of VD1 by prolonged hyperpolarization revealed a distinct, low-frequency firing pattern in RPD2. This suggests that strong electrical coupling is key to maintaining a synchronous output and proper firing rate.

  18. Radiation-epidemiological Study of Cerebrovascular Diseases in the Cohort of Russian Recovery Operation Workers of the Chernobyl Accident.

    PubMed

    Kashcheev, V V; Chekin, S Yu; Maksioutov, M A; Tumanov, K A; Menyaylo, A N; Kochergina, E V; Kashcheeva, P V; Gorsky, A I; Shchukina, N V; Karpenko, S V; Ivanov, V K

    2016-08-01

    The paper presents an analysis of the incidence of cerebrovascular diseases (CeVD) in the cohort of Russian workers involved in recovery tasks after the Chernobyl accident. The studied cohort consists of 53,772 recovery operation workers (liquidators) who arrived in the zone of the Chernobyl accident within the first year after this accident (26 April 1986-26 April 1987). The mean external whole body dose in the cohort was 0.161 Gy, while individual doses varied from 0.0001 Gy to 1.42 Gy. During the follow-up period 1986-2012, a total of 23,264 cases of CeVD were diagnosed as a result of annual health examinations. A Poisson regression model was applied for estimation of radiation risks and for an assessment of other risk factors of CeVD. The following factors were considered as risk factors for CeVD: the dose, duration of the liquidators' work in the Chernobyl zone, and the concomitant diseases (hypertension, ischemic heart disease, atherosclerosis, and diabetes). The baseline incidence of CeVD is statistically significantly (p < 0.001) associated with all studied concomitant diseases. The incidence of CeVD has revealed a statistically significant dose response with the lack of a latent period and with the average ERR/Gy = 0.45, 95% CI: (0.28, 0.62), p < 0.001. Radiation risks of CeVD statistically significantly (p = 0.03) varied with the duration of liquidators' stay in the Chernobyl zone; for those who stayed in the Chernobyl zone less than 6 wk, ERR/Gy = 0.64, 95% CI = (0.38; 0.93), p < 0.001. Among studied concomitant diseases, diabetes mellitus statistically significantly (p = 0.002) increases the radiation risk of CeVD: for liquidators with diagnosed diabetes, ERR/Gy = 1.29. PMID:27356064

  19. Van der Waals coefficients beyond the classical shell model

    SciTech Connect

    Tao, Jianmin; Fang, Yuan; Hao, Pan; Scuseria, G. E.; Ruzsinszky, Adrienn; Perdew, John P.

    2015-01-14

    Van der Waals (vdW) coefficients can be accurately generated and understood by modelling the dynamic multipole polarizability of each interacting object. Accurate static polarizabilities are the key to accurate dynamic polarizabilities and vdW coefficients. In this work, we present and study in detail a hollow-sphere model for the dynamic multipole polarizability proposed recently by two of the present authors (JT and JPP) to simulate the vdW coefficients for inhomogeneous systems that allow for a cavity. The inputs to this model are the accurate static multipole polarizabilities and the electron density. A simplification of the full hollow-sphere model, the single-frequency approximation (SFA), circumvents the need for a detailed electron density and for a double numerical integration over space. We find that the hollow-sphere model in SFA is not only accurate for nanoclusters and cage molecules (e.g., fullerenes) but also yields vdW coefficients among atoms, fullerenes, and small clusters in good agreement with expensive time-dependent density functional calculations. However, the classical shell model (CSM), which inputs the static dipole polarizabilities and estimates the static higher-order multipole polarizabilities therefrom, is accurate for the higher-order vdW coefficients only when the interacting objects are large. For the lowest-order vdW coefficient C{sub 6}, SFA and CSM are exactly the same. The higher-order (C{sub 8} and C{sub 10}) terms of the vdW expansion can be almost as important as the C{sub 6} term in molecular crystals. Application to a variety of clusters shows that there is strong non-additivity of the long-range vdW interactions between nanoclusters.

  20. Dynamical screening of van der Waals interactions in nanostructured solids: Sublimation of fullerenes

    SciTech Connect

    Tao, Jianmin; Yang, Jing; Rappe, Andrew M.

    2015-04-28

    Sublimation energy is one of the most important properties of molecular crystals, but it is difficult to study, because the attractive long-range van der Waals (vdW) interaction plays an important role. Here, we apply efficient semilocal density functional theory (DFT), corrected with the dynamically screened vdW interaction (DFT + vdW), the Rutgers-Chalmers nonlocal vdW-DF, and the pairwise-based dispersion-corrected DFT-D2 developed by Grimme and co-workers, to study the sublimation of fullerenes. We find that the short-range part, which accounts for the interaction due to the orbital overlap between fullerenes, is negligibly small. Our calculation shows that there exists a strong screening effect on the vdW interaction arising from the valence electrons of fullerenes. On the other hand, higher-order contributions can be as important as the leading-order term. The reasons are that (i) the surface of fullerene molecules is metallic and thus highly polarizable, (ii) the band gap of fullerene solids is small (less than 2 eV), and (iii) fullerene molecules in the solid phase are so densely packed, yielding the high valence electron density and small equilibrium intermolecular distances (the first nearest neighbor distance is only about 10 Å for C{sub 60}). However, these two effects make opposite contributions, leading to significant error cancellation between these two contributions. We demonstrate that, by considering higher-order contributions and the dynamical screening, the DFT + vdW method can yield sublimation energies of fullerenes in good agreement with reference values, followed by vdW-DF and DFT-D2. The insights from this study are important for a better understanding of the long-range nature of vdW interactions in nanostructured solids.

  1. Van der Waals epitaxial growth of two-dimensional single-crystalline GaSe domains on graphene

    DOE PAGES

    Li, Xufan; Basile, Leonardo; Huang, Bing; Ma, Cheng; Lee, Jaekwang; Vlassiouk, Ivan V.; Puretzky, Alexander A.; Lin, Ming -Wei; Chi, Miaofang; Idrobo Tapia, Juan Carlos; et al

    2015-07-22

    Two-dimensional (2D) van der Waals (vdW) heterostructures are a family of artificially-structured materials that promise tunable optoelectronic properties for devices with enhanced functionalities. Compared to stamping, direct epitaxy of vdW heterostructures is ideal for clean interlayer interfaces and scalable device fabrication. Here, we explore the synthesis and preferred orientations of 2D GaSe atomic layers on graphene (Gr) by vdW epitaxy. Guided by the wrinkles on graphene, GaSe nuclei form that share a predominant lattice orientation. Due to vdW epitaxial growth many nuclei grow as perfectly aligned crystals and coalesce to form large (tens of microns), single-crystal flakes. Through theoretical investigationsmore » of interlayer energetics, and measurements of preferred orientations by atomic-resolution STEM and electron diffraction, a 10.9 interlayer rotation of the GaSe lattice with respect to the underlying graphene is found to be the most energetically preferred vdW heterostructure with the largest binding energy and the longest-range ordering. These GaSe/Gr vdW heterostructures exhibit an enhanced Raman E21g band of monolayer GaSe along with highly-quenched photoluminescence due to strong charge transfer. Despite the very large lattice mismatch of GaSe/Gr through vdW epitaxy, the predominant orientation control and convergent formation of large single-crystal flakes demonstrated here is promising for the scalable synthesis of large-area vdW heterostructures for the development of new optical and optoelectronic devices.« less

  2. Van der Waals epitaxial growth of two-dimensional single-crystalline GaSe domains on graphene

    SciTech Connect

    Li, Xufan; Basile, Leonardo; Huang, Bing; Ma, Cheng; Lee, Jaekwang; Vlassiouk, Ivan V.; Puretzky, Alexander A.; Lin, Ming -Wei; Chi, Miaofang; Idrobo Tapia, Juan Carlos; Rouleau, Christopher M.; Sumpter, Bobby G.; Yoon, Mina; Geohegan, David B.; Xiao, Kai

    2015-07-22

    Two-dimensional (2D) van der Waals (vdW) heterostructures are a family of artificially-structured materials that promise tunable optoelectronic properties for devices with enhanced functionalities. Compared to stamping, direct epitaxy of vdW heterostructures is ideal for clean interlayer interfaces and scalable device fabrication. Here, we explore the synthesis and preferred orientations of 2D GaSe atomic layers on graphene (Gr) by vdW epitaxy. Guided by the wrinkles on graphene, GaSe nuclei form that share a predominant lattice orientation. Due to vdW epitaxial growth many nuclei grow as perfectly aligned crystals and coalesce to form large (tens of microns), single-crystal flakes. Through theoretical investigations of interlayer energetics, and measurements of preferred orientations by atomic-resolution STEM and electron diffraction, a 10.9 interlayer rotation of the GaSe lattice with respect to the underlying graphene is found to be the most energetically preferred vdW heterostructure with the largest binding energy and the longest-range ordering. These GaSe/Gr vdW heterostructures exhibit an enhanced Raman E21g band of monolayer GaSe along with highly-quenched photoluminescence due to strong charge transfer. Despite the very large lattice mismatch of GaSe/Gr through vdW epitaxy, the predominant orientation control and convergent formation of large single-crystal flakes demonstrated here is promising for the scalable synthesis of large-area vdW heterostructures for the development of new optical and optoelectronic devices.

  3. Combination of lenalidomide with vitamin D3 induces apoptosis in mantle cell lymphoma via demethylation of BIK

    PubMed Central

    Brosseau, C; Dousset, C; Touzeau, C; Maïga, S; Moreau, P; Amiot, M; Le Gouill, S; Pellat-Deceunynck, C

    2014-01-01

    Mantle cell lymphoma (MCL) is a currently incurable B-cell malignancy. Lenalidomide (Len) has been demonstrated to be one of the most efficient new treatment options. Because Len and 1α,25-dihydroxyvitamin (VD3) synergize to kill breast cancer cells, we investigated whether VD3 could increase the ability of Len to induce MCL cell death. While MCL cells were weakly sensitive to Len (1 μM), the addition of VD3 at physiological dose (100 nM) strongly increased cell death, accompanied by slowdown in cell cycle progression in MCL cell lines (n=4 out of 6) and primary samples (n=5 out of 7). The Len/VD3 treatment markedly increased the expression of the BH3-only BCL2-interacting killer (Bik) without affecting the expression of other Bcl-2 molecules. Immunoprecipitation assays demonstrated that Bik was free from anti-apoptotic partners, Bcl-2 and Bcl-xL, in treated cells. Moreover, silencing of BIK prevented apoptosis induced by Len/VD3, confirming the direct involvement of Bik in cell death. Bik accumulation induced by Len/VD3 was related to an increase in BIK mRNA levels, which resulted from a demethylation of BIK CpG islands. The sensitivity of MCL cells to Len/VD3 was similar to the response to 5-azacytidine, which also induced demethylation of BIK CpG islands. These preclinical data provide the rationale to investigate the role of VD3 in vivo in the response to Len. PMID:25165875

  4. NASA Astrophysics Data System (ADS)

    2016-01-01

    Here M = 1 /kB T, (kB is Boltzmann's constant, and T is the temperature), ED2 is the classical dissociation energy of D2 molecules, Eb is the binding energy, h is Planck's constant, A is the molecular moment of inertia of D2 molecules, vD and vD2 are vibrational frequency of D in bulk Er2O3 and gaseous states respectively, and m is the mass of D2 molecules.

  5. Van der Waals epitaxial double heterostructure: InAs/single-layer graphene/InAs.

    PubMed

    Hong, Young Joon; Yang, Jae Won; Lee, Wi Hyoung; Ruoff, Rodney S; Kim, Kwang S; Fukui, Takashi

    2013-12-17

    Van der Waals (vdW) epitaxial double heterostructures have been fabricated by vdW epitaxy of InAs nanostructures on both sides of graphene. InAs nanostructures diametrically form on/underneath graphene exclusively along As-polar direction, indicating polarity inversion of the double heterostructures. First-principles and density functional calculations demonstrate how and why InAs easily form to be double heterostructures with polarity inversion.

  6. Interaction of boron with graphite: A van der Waals density functional study

    NASA Astrophysics Data System (ADS)

    Liu, Juan; Wang, Chen; Liang, Tongxiang; Lai, Wensheng

    2016-08-01

    Boron doping has been widely investigated to improve oxidation resistance of graphite. In this work the interaction of boron with graphite is investigated by a van der Waals density-functional approach (vdW-DF). The traditional density-functional theory (DFT) is well accounted for the binding in boron-substituted graphite. However, to investigate the boron atom on graphite surface and the interstitial impurities require use of a description of graphite interlayer binding. Traditional DFT cannot describe the vdW physics, for instance, GGA calculations show no relevant binding between graphite sheets. LDA shows some binding, but they fail to provide an accurate account of vdW forces. In this paper, we compare the calculation results of graphite lattice constant and cohesive energy by several functionals, it shows that vdW-DF such as two optimized functionals optB88-vdW and optB86b-vdW give much improved results than traditional DFT. The vdW-DF approach is then applied to study the interaction of boron with graphite. Boron adsorption, substitution, and intercalation are discussed in terms of structural parameters and electronic structures. When adsorbing on graphite surface, boron behaves as π electron acceptor. The π electron approaches boron atom because of more electropositive of boron than carbon. For substitution situation, the hole introduced by boron mainly concentrates on boron and the nearest three carbon atoms. The B-doped graphite system with the hole has less ability to offer electrons to oxygen, ultimately resulted in the inhibition of carbon oxidation. For interstitial doping, vdW-DFs show more accurate formation energy than LDA. PBE functional cannot describe the interstitial boron in graphite reasonably because of the ignoring binding of graphite sheets. The investigation of electron structures of boron doped graphite will play an important role in understanding the oxidation mechanism in further study.

  7. Radiation-epidemiological Study of Cerebrovascular Diseases in the Cohort of Russian Recovery Operation Workers of the Chernobyl Accident.

    PubMed

    Kashcheev, V V; Chekin, S Yu; Maksioutov, M A; Tumanov, K A; Menyaylo, A N; Kochergina, E V; Kashcheeva, P V; Gorsky, A I; Shchukina, N V; Karpenko, S V; Ivanov, V K

    2016-08-01

    The paper presents an analysis of the incidence of cerebrovascular diseases (CeVD) in the cohort of Russian workers involved in recovery tasks after the Chernobyl accident. The studied cohort consists of 53,772 recovery operation workers (liquidators) who arrived in the zone of the Chernobyl accident within the first year after this accident (26 April 1986-26 April 1987). The mean external whole body dose in the cohort was 0.161 Gy, while individual doses varied from 0.0001 Gy to 1.42 Gy. During the follow-up period 1986-2012, a total of 23,264 cases of CeVD were diagnosed as a result of annual health examinations. A Poisson regression model was applied for estimation of radiation risks and for an assessment of other risk factors of CeVD. The following factors were considered as risk factors for CeVD: the dose, duration of the liquidators' work in the Chernobyl zone, and the concomitant diseases (hypertension, ischemic heart disease, atherosclerosis, and diabetes). The baseline incidence of CeVD is statistically significantly (p < 0.001) associated with all studied concomitant diseases. The incidence of CeVD has revealed a statistically significant dose response with the lack of a latent period and with the average ERR/Gy = 0.45, 95% CI: (0.28, 0.62), p < 0.001. Radiation risks of CeVD statistically significantly (p = 0.03) varied with the duration of liquidators' stay in the Chernobyl zone; for those who stayed in the Chernobyl zone less than 6 wk, ERR/Gy = 0.64, 95% CI = (0.38; 0.93), p < 0.001. Among studied concomitant diseases, diabetes mellitus statistically significantly (p = 0.002) increases the radiation risk of CeVD: for liquidators with diagnosed diabetes, ERR/Gy = 1.29.

  8. Seasonal variations in vitamin D status in indoor and outdoor female athletes

    PubMed Central

    MARUYAMA-NAGAO, ASAKO; SAKURABA, KEISHOKU; SUZUKI, YOSHIO

    2016-01-01

    Vitamin D (VD) insufficiency is a concern, particularly among young females. The VD status shows seasonal variations, since it correlates with duration of sunlight exposure. VD insufficiency in indoor athletes is therefore suggested in winter. The aim of the present study was to determine seasonal variations in VD and bone status among indoor and outdoor female athletes. The prospective study was conducted in participants aged 20–22 years old. The participants comprised of 15 indoor and 15 outdoor athletes. The biochemical markers and bone parameters were measured in March, June, September and December. The serum 25-hydroxyvitamin D (25-OH-VD) concentration showed a seasonal oscillation, with a nadir in March (indoor, 19±4.0 ng/ml; outdoor, 32±2.7 ng/ml) and a peak in September (indoor, 32±6.6 ng/ml; outdoor, 39±5.7 ng/ml). The amplitude of oscillation was greater in the indoor compared to the outdoor athletes. Seasonal variations in serum calcium exhibited a similar pattern, while the parathyroid hormone showed an inverse pattern to serum 25-OH-VD. The nadir in bone mass, measured as speed of sound, occurred in June after peaking in December among the indoor and outdoor athletes. The pattern followed 3 months after the changes in 25-OH-VD. Indoor sports athletes are more susceptible to VD insufficiency compared to outdoor sports athletes. Insufficiency is most likely to arise in winter, and could affect bone mineralization observed 3 months after. PMID:27347414

  9. Epitaxial growth of molecular crystals on van der waals substrates for high-performance organic electronics.

    PubMed

    Lee, Chul-Ho; Schiros, Theanne; Santos, Elton J G; Kim, Bumjung; Yager, Kevin G; Kang, Seok Ju; Lee, Sunwoo; Yu, Jaeeun; Watanabe, Kenji; Taniguchi, Takashi; Hone, James; Kaxiras, Efthimios; Nuckolls, Colin; Kim, Philip

    2014-05-01

    Epitaxial van der Waals (vdW) heterostructures of organic and layered materials are demonstrated to create high-performance organic electronic devices. High-quality rubrene films with large single-crystalline domains are grown on h-BN dielectric layers via vdW epitaxy. In addition, high carrier mobility comparable to free-standing single-crystal counterparts is achieved by forming interfacial electrical contacts with graphene electrodes. PMID:24458727

  10. Davydov coupling as a factor influencing the H-bond IR signature: Computational study of the IR spectra of 3-thiopheneacrylic acid crystal

    NASA Astrophysics Data System (ADS)

    Rekik, Najeh; Al-Agel, Faisal A.; Flakus, Henryk T.

    2016-03-01

    In this work, we have studied the role played by Davydov coupling in the evolution of the fine structure of the IR spectra of 3-thiopheneacrylic acid dimer crystal. For this purpose, we took into account the linear dependence of the Davydov coupling on the position coordinate Qi(i = 1, 2) of the slow frequency O←sbnd H …O→ mode of the two H-bond bridges of the cyclic dimer. The Davydov coupling VD term was expanded up to first order with respect to the slow mode coordinate Qi. We have considered: VD (Q1 ,Q2) =VD0 + Θ (Q1 +Q2). That leads to the anharmonic expression of the Davydov coupling parameter VD: VD(Qg) =VD0 +√{ 2} ΘQg within the symmetrized coordinates. The effect of the second order parameter (Θ) of Davydov coupling on to the spectral density was undertaken. The numerical calculations clearly show that the crystal spectral properties of the infrared υOsbnd H stretching band remain in a close relation with the new anharmonic coupling parameter and provide a direct evidence of the increase of the level density and the spectral broadening.

  11. Study of relationship between volume of distribution and body weight application to amikacin.

    PubMed

    Rughoo, L; Bourguignon, L; Maire, P; Ducher, M

    2014-06-01

    Amikacin use is difficult because of its narrow therapeutic and its pharmacokinetic variability. This variability of amikacin is not well known. To adapt amikacin the physician assumes that there is a linear and continuous relation between the volume of distribution and the body weight. The objective of our study was to evaluate the relationship between the volume of distribution (Vd) and the body weight (BW) using a non parametric statistical analysis of dependence so called Z method. Retrospective pharmacokinetic population study and statistic analysis. 872 patients receiving intravenous amikacin. The volume of distribution was modelled using the Non Parametric Adaptive Grid algorithm (NPAG) for a two-compartment model with intravenous infusion. Z coefficient was performed to evaluate the relationships between Vd and BW. For the 872 patients (mean age of 73 ± 17 years) dispatched as follow 53 % female and 47 % male, the analysis of the statistical relationships by the non parametric Z analysis showed a scattered linkage between Vd and BW. For the whole population, the relationship between Vd and BW was not linear (regression analysis). Z analysis demonstrated that only for 80 % of patients there is a relationship between Vd and BW. For these patients, regression analysis give a significant adjustment of a linear model (r = 0.47, p < 0.001). In the whole studied population there is not a continuous and linear relationship between Vd estimated by NPAG and the BW. These results underline the difficulties to adapt doses of amikacin with only BW information.

  12. Correlation between Motor Cortex Excitability Changes and Cognitive Impairment in Vascular Depression: Pathophysiological Insights from a Longitudinal TMS Study.

    PubMed

    Pennisi, Manuela; Lanza, Giuseppe; Cantone, Mariagiovanna; Ricceri, Riccardo; Spampinato, Concetto; Pennisi, Giovanni; Di Lazzaro, Vincenzo; Bella, Rita

    2016-01-01

    Background. Transcranial magnetic stimulation (TMS) highlighted functional changes in dementia, whereas there are few data in patients with vascular cognitive impairment-no dementia (VCI-ND). Similarly, little is known about the neurophysiological impact of vascular depression (VD) on deterioration of cognitive functions. We test whether depression might affect not only cognition but also specific cortical circuits in subcortical vascular disease. Methods. Sixteen VCI-ND and 11 VD patients, age-matched with 15 controls, underwent a clinical-cognitive, neuroimaging, and TMS assessment. After approximately two years, all participants were prospectively reevaluated. Results. At baseline, a significant more pronounced intracortical facilitation (ICF) was found in VCI-ND patients. Reevaluation revealed an increase of the global excitability in both VCI-ND and VD subjects. At follow-up, the ICF of VCI-ND becomes similar to the other groups. Only VD patients showed cognitive deterioration. Conclusions. Unlike VD, the hyperfacilitation found at baseline in VCI-ND patients suggests enhanced glutamatergic neurotransmission that might contribute to the preservation of cognitive functioning. The hyperexcitability observed at follow-up in both groups of patients also indicates functional changes in glutamatergic neurotransmission. The mechanisms enhancing the risk of dementia in VD might be related either to subcortical vascular lesions or to the lack of compensatory functional cortical changes. PMID:27525127

  13. New Vehicle Detection Method with Aspect Ratio Estimation for Hypothesized Windows

    PubMed Central

    Kim, Jisu; Baek, Jeonghyun; Park, Yongseo; Kim, Euntai

    2015-01-01

    All kinds of vehicles have different ratios of width to height, which are called the aspect ratios. Most previous works, however, use a fixed aspect ratio for vehicle detection (VD). The use of a fixed vehicle aspect ratio for VD degrades the performance. Thus, the estimation of a vehicle aspect ratio is an important part of robust VD. Taking this idea into account, a new on-road vehicle detection system is proposed in this paper. The proposed method estimates the aspect ratio of the hypothesized windows to improve the VD performance. Our proposed method uses an Aggregate Channel Feature (ACF) and a support vector machine (SVM) to verify the hypothesized windows with the estimated aspect ratio. The contribution of this paper is threefold. First, the estimation of vehicle aspect ratio is inserted between the HG (hypothesis generation) and the HV (hypothesis verification). Second, a simple HG method named a signed horizontal edge map is proposed to speed up VD. Third, a new measure is proposed to represent the overlapping ratio between the ground truth and the detection results. This new measure is used to show that the proposed method is better than previous works in terms of robust VD. Finally, the Pittsburgh dataset is used to verify the performance of the proposed method. PMID:26690177

  14. Interactions between late acting proteins required for peptidoglycan synthesis during sporulation

    PubMed Central

    Fay, Allison; Meyer, Pablo; Dworkin, Jonathan

    2010-01-01

    The requirement of peptidoglycan synthesis for growth complicates the analysis of interactions between proteins involved in this pathway. In particular, the later steps that involve membrane-linked substrates have proven largely recalcitrant to in vivo analysis. Here we have taken advantage of the peptidoglycan synthesis that occurs during sporulation in Bacillus subtilis to examine the interactions between SpoVE, a non-essential, sporulation-specific homolog of the well-conserved and essential SEDS proteins, and SpoVD, a non-essential class B penicillin binding protein (PBP). We found that localization of SpoVD is dependent on SpoVE and that SpoVD protects SpoVE from in vivo proteolysis. Co-immunoprecipitations and Fluorescence Resonance Energy Transfer experiments indicated that SpoVE and SpoVD interact and co-affinity purification in E. coli demonstrated that this interaction is direct. Finally, we generated a functional protein consisting of a SpoVE-SpoVD fusion and found that a loss-of-function point mutation in either part of the fusion resulted in a loss of function of the entire fusion that was not complemented by a wild type protein. Thus, SpoVE has a direct and functional interaction with SpoVD and this conclusion will facilitate understanding the essential function SpoVE and related SEDS proteins such as FtsW and RodA play in bacterial growth and division. PMID:20417640

  15. Visual disturbance following sclerotherapy for varicose veins, reticular veins and telangiectasias: a systematic literature review.

    PubMed

    Willenberg, T; Smith, P C; Shepherd, A; Davies, A H

    2013-04-01

    The objective of the study was to review the literature reporting visual disturbance (VD)following sclerotherapy for varicose veins. Underlying mechanisms will be discussed. A literature search of the databases Medline and Google Scholar was performed. Original articles including randomized trials, case series and case reports reporting VD in humans following sclerotherapy for varicose veins were included. Additional references were also obtained if they had been referenced in related publications. The search yielded 4948 results of which 25 reports were found to meet the inclusion criteria. In larger series with at least 500 included patients the prevalence of VD following sclerotherapy ranges from 0.09% to 2%. In most reports foam sclerotherapy was associated with VD (19); exclusive use of liquid sclerosant was reported in two cases, some reports included foam and liquid sclerosant (4). There were no persistent visual disorders reported. VD occurred with polidocanol and sodium tetradecyl sulphate in different concentrations (0.25–3%). Various forms of foam preparation including various ways of foam production and the liquid –air ratio (1 or 2 parts of liquid mixed with 3, 4 or 5 parts of air) were reported in association with the occurrence of VD. VDs following sclerotherapy for varicose veins are rare and all reported events were transient. Bubble embolism or any kind of embolism seems unlikely to be the only underlying mechanism. A systemic inflammatory response following sclerotherapy has been suggested. Further research to clarify the mechanism of action of sclerosants is required.

  16. Non-additivity of molecule-surface van der Waals potentials from force measurements

    PubMed Central

    Wagner, Christian; Fournier, Norman; Ruiz, Victor G.; Li, Chen; Müllen, Klaus; Rohlfing, Michael; Tkatchenko, Alexandre; Temirov, Ruslan; Tautz, F. Stefan

    2014-01-01

    Van der Waals (vdW) forces act ubiquitously in condensed matter. Despite being weak on an atomic level, they substantially influence molecular and biological systems due to their long range and system-size scaling. The difficulty to isolate and measure vdW forces on a single-molecule level causes our present understanding to be strongly theory based. Here we show measurements of the attractive potential between differently sized organic molecules and a metal surface using an atomic force microscope. Our choice of molecules and the large molecule-surface separation cause this attraction to be purely of vdW type. The experiment allows testing the asymptotic vdW force law and its validity range. We find a superlinear growth of the vdW attraction with molecular size, originating from the increased deconfinement of electrons in the molecules. Because such non-additive vdW contributions are not accounted for in most first-principles or empirical calculations, we suggest further development in that direction. PMID:25424490

  17. Non-additivity of molecule-surface van der Waals potentials from force measurements.

    PubMed

    Wagner, Christian; Fournier, Norman; Ruiz, Victor G; Li, Chen; Müllen, Klaus; Rohlfing, Michael; Tkatchenko, Alexandre; Temirov, Ruslan; Tautz, F Stefan

    2014-11-26

    Van der Waals (vdW) forces act ubiquitously in condensed matter. Despite being weak on an atomic level, they substantially influence molecular and biological systems due to their long range and system-size scaling. The difficulty to isolate and measure vdW forces on a single-molecule level causes our present understanding to be strongly theory based. Here we show measurements of the attractive potential between differently sized organic molecules and a metal surface using an atomic force microscope. Our choice of molecules and the large molecule-surface separation cause this attraction to be purely of vdW type. The experiment allows testing the asymptotic vdW force law and its validity range. We find a superlinear growth of the vdW attraction with molecular size, originating from the increased deconfinement of electrons in the molecules. Because such non-additive vdW contributions are not accounted for in most first-principles or empirical calculations, we suggest further development in that direction.

  18. Accurate van der Waals coefficients between fullerenes and fullerene-alkali atoms and clusters: Modified single-frequency approximation

    NASA Astrophysics Data System (ADS)

    Tao, Jianmin; Mo, Yuxiang; Tian, Guocai; Ruzsinszky, Adrienn

    2016-08-01

    Long-range van der Waals (vdW) interaction is critically important for intermolecular interactions in molecular complexes and solids. However, accurate modeling of vdW coefficients presents a great challenge for nanostructures, in particular for fullerene clusters, which have huge vdW coefficients but also display very strong nonadditivity. In this work, we calculate the coefficients between fullerenes, fullerene and sodium clusters, and fullerene and alkali atoms with the hollow-sphere model within the modified single-frequency approximation (MSFA). In the MSFA, we assume that the electron density is uniform in a molecule and that only valence electrons in the outmost subshell of atoms contribute. The input to the model is the static multipole polarizability, which provides a sharp cutoff for the plasmon contribution outside the effective vdW radius. We find that the model can generate C6 in excellent agreement with expensive wave-function-based ab initio calculations, with a mean absolute relative error of only 3 % , without suffering size-dependent error. We show that the nonadditivities of the coefficients C6 between fullerenes and C60 and sodium clusters Nan revealed by the model agree remarkably well with those based on the accurate reference values. The great flexibility, simplicity, and high accuracy make the model particularly suitable for the study of the nonadditivity of vdW coefficients between nanostructures, advancing the development of better vdW corrections to conventional density functional theory.

  19. Correlation between Motor Cortex Excitability Changes and Cognitive Impairment in Vascular Depression: Pathophysiological Insights from a Longitudinal TMS Study

    PubMed Central

    Cantone, Mariagiovanna; Spampinato, Concetto

    2016-01-01

    Background. Transcranial magnetic stimulation (TMS) highlighted functional changes in dementia, whereas there are few data in patients with vascular cognitive impairment-no dementia (VCI-ND). Similarly, little is known about the neurophysiological impact of vascular depression (VD) on deterioration of cognitive functions. We test whether depression might affect not only cognition but also specific cortical circuits in subcortical vascular disease. Methods. Sixteen VCI-ND and 11 VD patients, age-matched with 15 controls, underwent a clinical-cognitive, neuroimaging, and TMS assessment. After approximately two years, all participants were prospectively reevaluated. Results. At baseline, a significant more pronounced intracortical facilitation (ICF) was found in VCI-ND patients. Reevaluation revealed an increase of the global excitability in both VCI-ND and VD subjects. At follow-up, the ICF of VCI-ND becomes similar to the other groups. Only VD patients showed cognitive deterioration. Conclusions. Unlike VD, the hyperfacilitation found at baseline in VCI-ND patients suggests enhanced glutamatergic neurotransmission that might contribute to the preservation of cognitive functioning. The hyperexcitability observed at follow-up in both groups of patients also indicates functional changes in glutamatergic neurotransmission. The mechanisms enhancing the risk of dementia in VD might be related either to subcortical vascular lesions or to the lack of compensatory functional cortical changes. PMID:27525127

  20. Molecular characterization and functional analysis of a specific secreted protein from highly virulent defoliating Verticillium dahliae.

    PubMed

    Liu, Shao-Yan; Chen, Jie-Yin; Wang, Jin-Long; Li, Lei; Xiao, Hong-Li; Adam, Sami M; Dai, Xiao-Feng

    2013-10-25

    Verticillium dahliae Kleb. is a phytopathogenic fungus that causes wilt diseases in hundreds of dicotyledonous plant species. Previous research has demonstrated that the secretome plays an important role in the pathogenicity of V. dahliae. In this study, the specific secreted protein gene (VdSSP1) in highly virulent defoliating V. dahliae strain VDG1 was cloned, and considered to be a secreted protein by signal peptide activity assay. VdSSP1 deletion mutants in VDG1 significantly compromised virulence, and the fungal growth decreased in media with pectin and starch as carbon sources. Pathogenicity and carbon utilization were restored upon complementation of the VdSSP1 deletion strains or low virulence non-defoliating strain VDG2, which lacks VdSSP1. It is indicated that the virulence role of VdSSP1 is associated with plant cell wall degradation. In conclusion, our data suggested that VdSSP1 is a secreted protein that is engaged in the pathogenicity of the highly virulent defoliating V. dahliae.

  1. Motor cortex excitability in vascular depression.

    PubMed

    Bella, Rita; Ferri, Raffaele; Cantone, Mariagiovanna; Pennisi, Manuela; Lanza, Giuseppe; Malaguarnera, Giulia; Spampinato, Concetto; Giordano, Daniela; Raggi, Alberto; Pennisi, Giovanni

    2011-12-01

    The aim of this study was to evaluate excitatory/inhibitory intracortical circuit changes in patients with vascular depression, and whether there are any interhemispheric differences of motor cortical excitability. Fifteen vascular depressed elderly (VD), ten nondepressed subcortical vascular disease patients (SVD) and ten age-matched controls underwent bilateral motor threshold and paired-pulse studies. They were also assessed for their brain vascular burden at MRI and neuropsychological profile. Executive dysfunction and apathy were significantly higher in VD; we were unable to find significant differences in resting motor threshold, cortical silent period and paired-pulse curves between VD, SVD and controls, and between the two hemispheres in the VD group. Our findings might suggest that neurophysiological mechanisms underlying VD differ from those previously reported in Major Depression (reduced excitability in the left hemisphere) and seem to be similar to those of patients with SVD. Our findings also, support the "vascular depression" hypothesis, suggesting that in VD patients the depressive syndrome is not the primary disease but can be considered as one of the clinical manifestations in the wide symptom spectrum of the cerebral small vessel disease.

  2. A meta-analysis of the effects of nonphytate phosphorus on broiler performance and tibia ash concentration.

    PubMed

    Faridi, A; Gitoee, A; France, J

    2015-11-01

    Decreasing feed costs while maintaining broiler performance at a high level with minimal environmental pollution has become a major challenge for poultry nutritionists in recent years. In this regard, phosphorus (P) is a nutrient that is problematic. To overcome this, a comprehensive knowledge of the responses of broilers to P is needed and the factors that affect its utilization need better understanding. For this purpose, a meta-analysis was conducted using results published in the literature on the responses of broilers to different levels of nonphytate P (NPP), calcium (Ca), microbial phytase (MP), and vitamin D3 or its metabolites (VD). The effects of Ca, MP, and VD on NPP requirements were investigated. Results showed significant (P ≤ 0.0001) linear and quadratic effects of NPP on all the responses, viz. average daily gain (ADG), feed intake (FI), feed efficiency (FE), and tibia ash concentration (TA). Results showed the negative effect of high Ca levels on all investigated responses, although these deleterious effects were alleviated when levels of NPP were increased or MP and/or VD added. Synergistic effects of MP and VD on FI and TA were observed. Best performance for all responses was found when MP and VD were added to low or moderate levels of Ca and NPP. Optimization showed higher levels of NPP are required to maximize TA compared to ADG, FI, and FE. Based on our analysis, requirements for NPP were affected mostly by Ca (increased) and MP (decreased), and, to a lesser extent, VD (inconsistent). PMID:26500275

  3. Effects of vitamin D and yeast extract supplementation on turkey mortality and clostridial dermatitis incidence in a dexamethasone immunosuppression model.

    PubMed

    Huff, G R; Huff, W E; Ratha, N C

    2014-12-01

    Clostridial dermatitis (CD) is a production disease of commercial turkeys that is characterized by sudden mortality in market-aged male birds and by lesions that include fluid and air bubbles under the skin of the thigh, breast, and tail area. We have developed a model for CD using dexamethasone (Dex) injection that suggests this disease may be related to stressors during the last stages of turkey production. Male turkeys were provided with control feed and water or with feed supplemented with a commercial yeast extract (YE) product, water supplemented with vitamin D (VD), or the combination. At 6, 11, and 15 wk of age birds were treated with three intramuscular injections of Dex over a 5-day period. Both YE and VD, but not the combination, decreased early mortality. At week 7 mortality was increased by VD, and cellulitis lesions were seen in 7/8 mortalities. Mortality at week 12 was decreased by both YE and the combination of YE and VD, and cellulitis lesions were seen in 8/17 mortalities. There were no significant differences in mortality at week 16. Total mortality was 66 birds, and 23 of these had cellulitis lesions (38%). There were no YE-treated birds with CD lesions; however, 67% of VD-treated birds had CD lesions. This study suggests that feed supplementation with YE may improve the ability of turkeys to withstand the stressors during late production and provide protection against the development of CD; however, high levels of VD supplementation may be detrimental.

  4. The generation of C-3α epimer of 25-hydroxyvitamin D and its biological effects on bone mineral density in adult rodents.

    PubMed

    Bianchini, Christina; Lavery, Paula; Agellon, Sherry; Weiler, Hope A

    2015-05-01

    The source and function of C-3α epimer of 25(OH)D (C-3 epimer) is unknown. The objectives were to (1) establish if increasing doses of vitamin D (VD) results in a proportionate dose-response in C-3 epimer; and (2) determine the biological response of bone to C-3 epimer treatment. Sprague Dawley rats (12 weeks, n = 36 female, n = 36 male) were randomized to control AIN93-M diet (1 IU VD3/g diet) or an experimental diet for 8 weeks containing VD3 at 2 or 4 IU/g diet, C-3 epimer at 0.5 or 1 IU/g diet or 25(OH)D (0.5 IU/g diet). BW and food consumption were measured weekly. Blood was sampled at week 0, 4, and 8 for assessment of VD metabolites and bone metabolism biomarkers. DXA (week 0, 4, and 8) and in vivo micro CT (μCT) (week 0 and 8) were performed in vivo plus ex vivo μCT imaging and bone biomechanics. Dietary intake and anthropometry did not differ among diet groups. The dose-response of VD generated significantly elevated C-3 epimer only in females with concentrations of 4 IU VD diet group [mean 84.6 (62.5) nmol/L] exceeding control [mean 21.4 (18.5) nmol/L, p = 0.005]. Both sexes in the 25(OH)D group did not show significant increases in C-3 epimer, whereas 0.5 and 1 IU epimer groups exceeded 100 nmol/L of C-3 epimer by 8 weeks. These data suggest C-3 epimer is endogenously generated with higher intakes of VD. Endogenous and exogenous C-3 epimer accumulates in serum without impact upon bone health outcomes in a healthy young adult model over 8 weeks.

  5. Attitude of future healthcare provider towards vitamin D significance in relation to sunlight exposure

    PubMed Central

    Qureshi, Aysha Zia; Zia, Zubia; Gitay, Mehnaz Nuruddin; Khan, Muhammad Umair; Khan, Muhammad Saad

    2015-01-01

    Objective: Nature is the kindest of all to provide man with all the necessary components for a healthy life at easily accessible lengths. The deprivation arises with unawareness and lack of correct measures to extract the benefits. Medical education makes the youth aware of the numerous disorders and diseases, as well as their preventions and treatments. This awareness needs to be realized and implemented in the society, and it is not possible without the advisers acting on the same lines. Since doctors are the most trusted and their advice is adopted without much thought, it is extremely inevitable to analyze the attitude of medical students of various levels to understand the cause of their negligence toward their own deficiencies, the focus for this study being vitamin D (VD). Method: A cross sectional descriptive study was done on undergraduate medical students of health profession from different universities of Pakistan to access the awareness regarding VD deficiency associated with sunlight. Informed consent was duly signed by each participant after which self-constructed questionnaire was provided to them and data are collected. SPSS 17 was used for Statistical analysis. Results: Final students are well aware of VD significance, take food rich in VD but still suffer from fatigue and muscular pain. No treatment was taken for fatigue and muscular pain by majority of these sufferers and those who took treatment were VD supplement. The health sufferers were mostly those who avoided sunlight highlighting the role of VD in maintaining an active lifestyle as well as the significance of sunlight in maintaining VD levels. Conclusion: It can be concluded that in spite of awareness, the role of sunlight exposure and the proper time and duration of exposure cannot be ignored to create a healthy and active society. PMID:26594118

  6. Growth differentiation factor-15 and white matter hyperintensities in cognitive impairment and dementia.

    PubMed

    Chai, Yuek Ling; Hilal, Saima; Chong, Jenny P C; Ng, Yan Xia; Liew, Oi Wah; Xu, Xin; Ikram, Mohammad Kamran; Venketasubramanian, Narayanaswamy; Richards, A Mark; Lai, Mitchell K P; Chen, Christopher P

    2016-08-01

    Vascular pathology plays an important role in the development of cognitive decline and dementia. In this context, growth differentiation factor-15 (GDF-15) has been suggested to be a biomarker due to its regulatory roles in inflammatory and trophic responses during tissue injury. However, limited data exist on the associations of GDF-15 with either cerebrovascular disease (CeVD) burden or the spectrum of cognitive impairment. Therefore, we aimed to study peripheral levels of GDF-15 incognitive impairment no dementia (CIND) or Alzheimer disease (AD) subjects assessed for CeVD using a case-control cohort design, with cases recruited from memory clinics and controls from memory clinics and the community. All subjects underwent detailed neuropsychological assessment, 3-Tesla magnetic resonance imaging, and venous blood draw. Subjects were classified as CIND or AD based on clinical criteria, while significant CeVD was defined as the presence of cortical infarcts and/or 2 lacunes or more, and/or confluent white matter hyperintensities (WMHs) in 2 or more brain regions. A total of 324 subjects were included in the study, of whom 80 had no cognitive impairment, 144 CIND and 100with AD. Higher GDF-15 levels were significantly associated with disease groups, especially in the presence of CeVD, namely, CIND with CeVD (odds ratios [OR]: 7.21; 95% confidence interval [CI]: 2.14-24.27) and AD with CeVD (OR: 21.87; 95% CI: 2.01-237.43). Among the different CeVD markers, only WMH was associated with higher GDF-15 levels (OR: 3.97; 95% CI: 1.79-8.83). The associations between GDF-15 and cognitive impairment as well as with WMH remained significant after excluding subjects with cardiovascular diseases. In conclusion, we showed that increased GDF-15 may be a biomarker for CIND and AD in subjects with WMH. PMID:27537582

  7. Cotransport of clay colloids and viruses through water-saturated vertically oriented columns packed with glass beads: Gravity effects.

    PubMed

    Syngouna, Vasiliki I; Chrysikopoulos, Constantinos V

    2016-03-01

    The cotransport of clay colloids and viruses in vertically oriented laboratory columns packed with glass beads was investigated. Bacteriophages MS2 and ΦX174 were used as model viruses, and kaolinite (ΚGa-1b) and montmorillonite (STx-1b) as model clay colloids. A steady flow rate of Q=1.5 mL/min was applied in both vertical up (VU) and vertical down (VD) flow directions. In the presence of KGa-1b, estimated mass recovery values for both viruses were higher for VD than VU flow direction, while in the presence of STx-1b the opposite was observed. However, for all cases examined, the produced mass of viruses attached onto suspended clay particles were higher for VD than VU flow direction, suggesting that the flow direction significantly influences virus attachment onto clays, as well as packed column retention of viruses attached onto suspended clays. KGa-1b hindered the transport of ΦX174 under VD flow, while STx-1b facilitated the transport of ΦX174 under both VU and VD flow directions. Moreover, KGa-1b and STx-1b facilitated the transport of MS2 in most of the cases examined except of the case where KGa-1b was present under VD flow. Also, the experimental data were used for the estimation of virus surface-coverages and virus surface concentrations generated by virus diffusion-limited attachment, as well as virus attachment due to sedimentation. Both sedimentation and diffusion limited virus attachment were higher for VD than VU flow, except the case of MS2 and STx-1b cotransport. The diffusion-limited attachment was higher for MS2 than ΦΧ174 for all cases examined.

  8. Incommensurate van der Waals epitaxy of nanowire arrays: a case study with ZnO on muscovite mica substrates.

    PubMed

    Utama, Muhammad Iqbal Bakti; Belarre, Francisco J; Magen, Cesar; Peng, Bo; Arbiol, Jordi; Xiong, Qihua

    2012-04-11

    The requirement of lattice matching between a material and its substrate for the growth of defect-free heteroepitaxial crystals can be circumvented with van der Waals epitaxy (vdWE). However, the utilization and characteristics of vdWE in nonlamellar/nonplanar nanoarchitectures are still not very well-documented. Here we establish the characteristics of vdWE in nanoarchitectures using a case study of ZnO nanowire (NW) array on muscovite mica substrate without any buffer/seed layer. With extensive characterizations involving electron microscopy, diffractometry, and the related analyses, we conclude that the NWs grown via vdWE exhibit an incommensurate epitaxy. The incommensurate vdWE allows a nearly complete lattice relaxation at the NW-substrate heterointerface without any defects, thus explaining the unnecessity of lattice matching for well-crystallized epitaxial NWs on muscovite mica. We then determine the polarity of the NW via a direct visualization of Zn-O dumbbells using the annular bright field scanning transmission electron miscroscopy (ABF-STEM) in order to identify which atoms are at the base of the NWs and responsible for the van der Waals interactions. The information from the ABF-STEM is then used to construct the proper atomic arrangement at the heterointerface with a 3D atomic modeling to corroborate the characteristics of the incommensurate vdWE. Our findings suggest that the vdWE might be extended for a wider varieties of compounds and epitaxial nanoarchitectures to serve as a universal epitaxy strategy.

  9. Van der Waals Epitaxial Growth of Two-Dimensional Single-Crystalline GaSe Domains on Graphene.

    PubMed

    Li, Xufan; Basile, Leonardo; Huang, Bing; Ma, Cheng; Lee, Jaekwang; Vlassiouk, Ivan V; Puretzky, Alexander A; Lin, Ming-Wei; Yoon, Mina; Chi, Miaofang; Idrobo, Juan C; Rouleau, Christopher M; Sumpter, Bobby G; Geohegan, David B; Xiao, Kai

    2015-08-25

    Two-dimensional (2D) van der Waals (vdW) heterostructures are a family of artificially structured materials that promise tunable optoelectronic properties for devices with enhanced functionalities. Compared to transferring, direct epitaxy of vdW heterostructures is ideal for clean interlayer interfaces and scalable device fabrication. Here we report the synthesis and preferred orientations of 2D GaSe atomic layers on graphene (Gr) by vdW epitaxy. GaSe crystals are found to nucleate predominantly on random wrinkles or grain boundaries of graphene, share a preferred lattice orientation with underlying graphene, and grow into large (tens of micrometers) irregularly shaped, single-crystalline domains. The domains are found to propagate with triangular edges that merge into the large single crystals during growth. Electron diffraction reveals that approximately 50% of the GaSe domains are oriented with a 10.5 ± 0.3° interlayer rotation with respect to the underlying graphene. Theoretical investigations of interlayer energetics reveal that a 10.9° interlayer rotation is the most energetically preferred vdW heterostructure. In addition, strong charge transfer in these GaSe/Gr vdW heterostructures is predicted, which agrees with the observed enhancement in the Raman E(2)1g band of monolayer GaSe and highly quenched photoluminescence compared to GaSe/SiO2. Despite the very large lattice mismatch of GaSe/Gr through vdW epitaxy, the predominant orientation control and convergent formation of large single-crystal flakes demonstrated here is promising for the scalable synthesis of large-area vdW heterostructures for the development of new optical and optoelectronic devices.

  10. Adsorption of organic molecules at the TiO2(110) surface: The effect of van der Waals interactions

    NASA Astrophysics Data System (ADS)

    Tillotson, Marcus J.; Brett, Peter M.; Bennett, Roger A.; Grau-Crespo, Ricardo

    2015-02-01

    Understanding the interaction of organic molecules with TiO2 surfaces is important for a wide range of technological applications. While density functional theory (DFT) calculations can provide valuable insight about these interactions, traditional DFT approaches with local exchange-correlation functionals suffer from a poor description of non-bonding van der Waals (vdW) forces. We examine here the vdW contribution to the interaction of small organic molecules (methane, methanol, formic acid and glycine) with the TiO2(110) surface, based on DFT calculations with the optB88-vdW functional, which incorporate non-local correlation. The adsorption geometries and energies at different configurations were also obtained in the standard generalized gradient approximation (GGA-PBE) for comparison. We find that the optB88-vdW consistently gives shorter surface adsorbate-to-surface distances and slightly stronger interactions than PBE for the weak (physisorbed) modes of adsorption. In the case of strongly adsorbed (chemisorbed) molecules both functionals give similar results for the adsorption geometries, and also similar values of the relative energies between different chemisorption modes for each molecule. In particular both functionals predict that dissociative adsorption is more favorable than molecular adsorption for methanol, formic acid and glycine, in general agreement with experiment. The dissociation energies obtained from both functionals are also very similar, indicating that vdW interactions do not affect the thermodynamics of surface deprotonation. However, the optB88-vdW always predicts stronger adsorption than PBE. The comparison of the methanol adsorption energies with values obtained from a Redhead analysis of temperature programmed desorption data suggests that optB88-vdW significantly overestimates the adsorption strength, although we warn about the uncertainties involved in such comparisons.

  11. Nucleotide Excision Repair and Vitamin D—Relevance for Skin Cancer Therapy

    PubMed Central

    Pawlowska, Elzbieta; Wysokinski, Daniel; Blasiak, Janusz

    2016-01-01

    Ultraviolet (UV) radiation is involved in almost all skin cancer cases, but on the other hand, it stimulates the production of pre-vitamin D3, whose active metabolite, 1,25-dihydroxyvitamin D3 (1,25VD3), plays important physiological functions on binding with its receptor (vitamin D receptor, VDR). UV-induced DNA damages in the form of cyclobutane pyrimidine dimers or (6-4)-pyrimidine-pyrimidone photoproducts are frequently found in skin cancer and its precursors. Therefore, removing these lesions is essential for the prevention of skin cancer. As UV-induced DNA damages are repaired by nucleotide excision repair (NER), the interaction of 1,25VD3 with NER components can be important for skin cancer transformation. Several studies show that 1,25VD3 protects DNA against damage induced by UV, but the exact mechanism of this protection is not completely clear. 1,25VD3 was also shown to affect cell cycle regulation and apoptosis in several signaling pathways, so it can be considered as a potential modulator of the cellular DNA damage response, which is crucial for mutagenesis and cancer transformation. 1,25VD3 was shown to affect DNA repair and potentially NER through decreasing nitrosylation of DNA repair enzymes by NO overproduction by UV, but other mechanisms of the interaction between 1,25VD3 and NER machinery also are suggested. Therefore, the array of NER gene functioning could be analyzed and an appropriate amount of 1.25VD3 could be recommended to decrease UV-induced DNA damage important for skin cancer transformation. PMID:27058533

  12. Different patterns of cortical excitability in major depression and vascular depression: a transcranial magnetic stimulation study

    PubMed Central

    2013-01-01

    Background Clinical and functional studies consider major depression (MD) and vascular depression (VD) as different neurobiological processes. Hypoexcitability of the left frontal cortex to transcranial magnetic stimulation (TMS) is frequently reported in MD, whereas little is known about the effects of TMS in VD. Thus, we aimed to assess and compare motor cortex excitability in patients with VD and MD. Methods Eleven VD patients, 11 recurrent drug-resistant MD patients, and 11 healthy controls underwent clinical, neuropsychological and neuroimaging evaluations in addition to bilateral resting motor threshold, cortical silent period, and paired-pulse TMS curves of intracortical excitability. All patients continued on psychotropic drugs, which were unchanged throughout the study. Results Scores on one of the tests evaluating frontal lobe abilities (Stroop Color-Word interference test) were worse in patients compared with controls. The resting motor threshold in patients with MD was significantly higher in the left hemisphere compared with the right (p < 0.05), and compared with the VD patients and controls. The cortical silent period was bilaterally prolonged in MD patients compared with VD patients and controls, with a statistically significant difference in the left hemisphere (p < 0.01). No differences were observed in the paired-pulse curves between patients and controls. Conclusions This study showed distinctive patterns of motor cortex excitability between late-onset depression with subcortical vascular disease and early-onset recurrent drug resistant MD. The data provide a TMS model of the different processes underlying VD and MD. Additionally, our results support the “Vascular depression hypothesis” at the neurophysiological level, and confirm the inter-hemispheric asymmetry to TMS in patients with MD. We were unable to support previous findings of impaired intracortical inhibitory mechanisms to TMS in patients with MD, although a drug

  13. Variable induction of vitellogenin genes in the varroa mite, Varroa destructor (Anderson & Trueman), by the honeybee, Apis mellifera L, host and its environment.

    PubMed

    Cabrera Cordon, A R; Shirk, P D; Duehl, A J; Evans, J D; Teal, P E A

    2013-02-01

    Transcript levels of vitellogenins (Vgs) in the varroa mite, Varroa destructor (Anderson & Trueman), were variably induced by interactions between the developing honeybee, Apis mellifera L, as a food source and the capped honeybee cell environment. Transcripts for two Vgs of varroa mites were sequenced and putative Vg protein products characterized. Sequence analysis of VdVg1 and VdVg2 proteins showed that each had greater similarity with Vg1 and Vg2 proteins from ticks, respectively, than between themselves and were grouped separately by phylogenetic analyses. This suggests there was a duplication of the ancestral acarine Vg gene prior to the divergence of the mites and ticks. Low levels of transcript were detected in immature mites, males and phoretic females. Following cell invasion by phoretic females, VdVg1 and VdVg2 transcript levels were up-regulated after cell capping to a maximum at the time of partial cocoon formation by the honeybee. During oviposition the two transcripts were differentially expressed with higher levels of VdVg2 being observed. A bioassay based on assessing the transcript levels was established. Increases in VdVg1 and VdVg2 transcripts were induced experimentally in phoretic females when they were placed inside a cell containing an early metamorphosing last instar bee but not when exposed to the metamorphosing bee alone. The variable response of Vg expression to the food source as well as environmental cues within the capped cell demonstrates that perturbation of host-parasite interactions may provide avenues to disrupt the reproductive cycle of the varroa mites and prevent varroasis.

  14. Vestibular and oculomotor influences on visual dependency

    PubMed Central

    Da Silva Melo, Mariane; Siddiqui, Aazim A.; Arshad, Qadeer; Patel, Mitesh

    2016-01-01

    The degree to which a person relies on visual stimuli for spatial orientation is termed visual dependency (VD). VD is considered a perceptual trait or cognitive style influenced by psychological factors and mediated by central reweighting of the sensory inputs involved in spatial orientation. VD is often measured with the rod-and-disk test, in which participants align a central rod to the subjective visual vertical (SVV) in the presence of a background that is either stationary or rotating around the line of sight—dynamic SVV. Although this task has been employed to assess VD in health and vestibular disease, what effect torsional nystagmic eye movements may have on individual performance is unknown. Using caloric ear irrigation, 3D video-oculography, and the rod-and-disk test, we show that caloric torsional nystagmus modulates measures of VD and demonstrate that increases in tilt after irrigation are positively correlated with changes in ocular torsional eye movements. When the direction of the slow phase of the torsional eye movement induced by the caloric is congruent with that induced by the rotating visual stimulus, there is a significant increase in tilt. When these two torsional components are in opposition, there is a decrease. These findings show that measures of VD can be influenced by oculomotor responses induced by caloric stimulation. The findings are of significance for clinical studies, as they indicate that VD, which often increases in vestibular disorders, is modulated not only by changes in cognitive style but also by eye movements, in particular nystagmus. PMID:27358321

  15. Insight into the description of van der Waals forces for benzene adsorption on transition metal (111) surfaces.

    PubMed

    Carrasco, Javier; Liu, Wei; Michaelides, Angelos; Tkatchenko, Alexandre

    2014-02-28

    Exploring the role of van der Waals (vdW) forces on the adsorption of molecules on extended metal surfaces has become possible in recent years thanks to exciting developments in density functional theory (DFT). Among these newly developed vdW-inclusive methods, interatomic vdW approaches that account for the nonlocal screening within the bulk [V. G. Ruiz, W. Liu, E. Zojer, M. Scheffler, and A. Tkatchenko, Phys. Rev. Lett. 108, 146103 (2012)] and improved nonlocal functionals [J. Klimeš, D. R. Bowler, and A. Michaelides, J. Phys.: Condens. Matter 22, 022201 (2010)] have emerged as promising candidates to account efficiently and accurately for the lack of long-range vdW forces in most popular DFT exchange-correlation functionals. Here we have used these two approaches to compute benzene adsorption on a range of close-packed (111) surfaces upon which it either physisorbs (Cu, Ag, and Au) or chemisorbs (Rh, Pd, Ir, and Pt). We have thoroughly compared the performance between the two classes of vdW-inclusive methods and when available compared the results obtained with experimental data. By examining the computed adsorption energies, equilibrium distances, and binding curves we conclude that both methods allow for an accurate treatment of adsorption at equilibrium adsorbate-substrate distances. To this end, explicit inclusion of electrodynamic screening in the interatomic vdW scheme and optimized exchange functionals in the case of nonlocal vdW density functionals is mandatory. Nevertheless, some discrepancies are found between these two classes of methods at large adsorbate-substrate separations.

  16. Roles of the catalytic subunit of cAMP-dependent protein kinase A in virulence and development of the soilborne plant pathogen Verticillium dahliae.

    PubMed

    Tzima, Aliki; Paplomatas, Epaminondas J; Rauyaree, Payungsak; Kang, Seogchan

    2010-05-01

    Verticillium dahliae is a soilborne fungus that causes vascular wilt disease in a broad range of hosts and survives for many years in the soil in the form of microsclerotia. Although the role of cAMP-dependent protein kinase A (PKA) has been extensively studied in foliar pathogens, there is limited information about its role in soilborne fungal pathogens that infect through the root system. Genome database search revealed the presence of two PKA catalytic subunit genes in V. dahliae, named VdPKAC1 and VdPKAC2. A phylogenetic analysis showed that VdPKAC2 groups with fungal PKA catalytic subunits that appear to play a minor role in PKA activity. This gene was expressed considerably lower than that of VdPKAC1. Although disruption of VdPKAC1 did not affect the ability of V. dahliae to infect through the roots of tomato and eggplant, disease severity was significantly reduced. Since pathogen-derived ethylene is presumed to play a major role in symptom induction in vascular wilt diseases, ethylene generation was measured in fungal culture. The mutants defective in VdPKAC1 produced less ethylene than the corresponding wild type strains, suggesting a regulatory role of PKA in ethylene biosynthesis. Growth rates of these mutants were similar to those of wild type strains, while the rate of spore germination was slightly elevated and conidia production was significantly reduced. When grown on minimal media, the mutants showed greater microsclerotia production compared with the wild type strains. These results suggest multiple roles of VdPKAC1, including virulence, conidiation, microsclerotia formation, and ethylene biosynthesis, in the soilborne fungus V. dahliae.

  17. Insight into the description of van der Waals forces for benzene adsorption on transition metal (111) surfaces

    NASA Astrophysics Data System (ADS)

    Carrasco, Javier; Liu, Wei; Michaelides, Angelos; Tkatchenko, Alexandre

    2014-02-01

    Exploring the role of van der Waals (vdW) forces on the adsorption of molecules on extended metal surfaces has become possible in recent years thanks to exciting developments in density functional theory (DFT). Among these newly developed vdW-inclusive methods, interatomic vdW approaches that account for the nonlocal screening within the bulk [V. G. Ruiz, W. Liu, E. Zojer, M. Scheffler, and A. Tkatchenko, Phys. Rev. Lett. 108, 146103 (2012)] and improved nonlocal functionals [J. Klimeš, D. R. Bowler, and A. Michaelides, J. Phys.: Condens. Matter 22, 022201 (2010)] have emerged as promising candidates to account efficiently and accurately for the lack of long-range vdW forces in most popular DFT exchange-correlation functionals. Here we have used these two approaches to compute benzene adsorption on a range of close-packed (111) surfaces upon which it either physisorbs (Cu, Ag, and Au) or chemisorbs (Rh, Pd, Ir, and Pt). We have thoroughly compared the performance between the two classes of vdW-inclusive methods and when available compared the results obtained with experimental data. By examining the computed adsorption energies, equilibrium distances, and binding curves we conclude that both methods allow for an accurate treatment of adsorption at equilibrium adsorbate-substrate distances. To this end, explicit inclusion of electrodynamic screening in the interatomic vdW scheme and optimized exchange functionals in the case of nonlocal vdW density functionals is mandatory. Nevertheless, some discrepancies are found between these two classes of methods at large adsorbate-substrate separations.

  18. Insight into the description of van der Waals forces for benzene adsorption on transition metal (111) surfaces.

    PubMed

    Carrasco, Javier; Liu, Wei; Michaelides, Angelos; Tkatchenko, Alexandre

    2014-02-28

    Exploring the role of van der Waals (vdW) forces on the adsorption of molecules on extended metal surfaces has become possible in recent years thanks to exciting developments in density functional theory (DFT). Among these newly developed vdW-inclusive methods, interatomic vdW approaches that account for the nonlocal screening within the bulk [V. G. Ruiz, W. Liu, E. Zojer, M. Scheffler, and A. Tkatchenko, Phys. Rev. Lett. 108, 146103 (2012)] and improved nonlocal functionals [J. Klimeš, D. R. Bowler, and A. Michaelides, J. Phys.: Condens. Matter 22, 022201 (2010)] have emerged as promising candidates to account efficiently and accurately for the lack of long-range vdW forces in most popular DFT exchange-correlation functionals. Here we have used these two approaches to compute benzene adsorption on a range of close-packed (111) surfaces upon which it either physisorbs (Cu, Ag, and Au) or chemisorbs (Rh, Pd, Ir, and Pt). We have thoroughly compared the performance between the two classes of vdW-inclusive methods and when available compared the results obtained with experimental data. By examining the computed adsorption energies, equilibrium distances, and binding curves we conclude that both methods allow for an accurate treatment of adsorption at equilibrium adsorbate-substrate distances. To this end, explicit inclusion of electrodynamic screening in the interatomic vdW scheme and optimized exchange functionals in the case of nonlocal vdW density functionals is mandatory. Nevertheless, some discrepancies are found between these two classes of methods at large adsorbate-substrate separations. PMID:24588188

  19. Cotransport of clay colloids and viruses through water-saturated vertically oriented columns packed with glass beads: Gravity effects.

    PubMed

    Syngouna, Vasiliki I; Chrysikopoulos, Constantinos V

    2016-03-01

    The cotransport of clay colloids and viruses in vertically oriented laboratory columns packed with glass beads was investigated. Bacteriophages MS2 and ΦX174 were used as model viruses, and kaolinite (ΚGa-1b) and montmorillonite (STx-1b) as model clay colloids. A steady flow rate of Q=1.5 mL/min was applied in both vertical up (VU) and vertical down (VD) flow directions. In the presence of KGa-1b, estimated mass recovery values for both viruses were higher for VD than VU flow direction, while in the presence of STx-1b the opposite was observed. However, for all cases examined, the produced mass of viruses attached onto suspended clay particles were higher for VD than VU flow direction, suggesting that the flow direction significantly influences virus attachment onto clays, as well as packed column retention of viruses attached onto suspended clays. KGa-1b hindered the transport of ΦX174 under VD flow, while STx-1b facilitated the transport of ΦX174 under both VU and VD flow directions. Moreover, KGa-1b and STx-1b facilitated the transport of MS2 in most of the cases examined except of the case where KGa-1b was present under VD flow. Also, the experimental data were used for the estimation of virus surface-coverages and virus surface concentrations generated by virus diffusion-limited attachment, as well as virus attachment due to sedimentation. Both sedimentation and diffusion limited virus attachment were higher for VD than VU flow, except the case of MS2 and STx-1b cotransport. The diffusion-limited attachment was higher for MS2 than ΦΧ174 for all cases examined. PMID:26747984

  20. Van der Waals Epitaxial Growth of Two-Dimensional Single-Crystalline GaSe Domains on Graphene.

    PubMed

    Li, Xufan; Basile, Leonardo; Huang, Bing; Ma, Cheng; Lee, Jaekwang; Vlassiouk, Ivan V; Puretzky, Alexander A; Lin, Ming-Wei; Yoon, Mina; Chi, Miaofang; Idrobo, Juan C; Rouleau, Christopher M; Sumpter, Bobby G; Geohegan, David B; Xiao, Kai

    2015-08-25

    Two-dimensional (2D) van der Waals (vdW) heterostructures are a family of artificially structured materials that promise tunable optoelectronic properties for devices with enhanced functionalities. Compared to transferring, direct epitaxy of vdW heterostructures is ideal for clean interlayer interfaces and scalable device fabrication. Here we report the synthesis and preferred orientations of 2D GaSe atomic layers on graphene (Gr) by vdW epitaxy. GaSe crystals are found to nucleate predominantly on random wrinkles or grain boundaries of graphene, share a preferred lattice orientation with underlying graphene, and grow into large (tens of micrometers) irregularly shaped, single-crystalline domains. The domains are found to propagate with triangular edges that merge into the large single crystals during growth. Electron diffraction reveals that approximately 50% of the GaSe domains are oriented with a 10.5 ± 0.3° interlayer rotation with respect to the underlying graphene. Theoretical investigations of interlayer energetics reveal that a 10.9° interlayer rotation is the most energetically preferred vdW heterostructure. In addition, strong charge transfer in these GaSe/Gr vdW heterostructures is predicted, which agrees with the observed enhancement in the Raman E(2)1g band of monolayer GaSe and highly quenched photoluminescence compared to GaSe/SiO2. Despite the very large lattice mismatch of GaSe/Gr through vdW epitaxy, the predominant orientation control and convergent formation of large single-crystal flakes demonstrated here is promising for the scalable synthesis of large-area vdW heterostructures for the development of new optical and optoelectronic devices. PMID:26202730

  1. Vitamin D for combination photodynamic therapy of skin cancer in individuals with vitamin D deficiency: Insights from a preclinical study in a mouse model of squamous cell carcinoma

    NASA Astrophysics Data System (ADS)

    Anand, Sanjay; Thomas, Erik; Hasan, Tayyaba; Maytin, Edward V.

    2016-03-01

    Combination photodynamic therapy (cPDT) in which vitamin D (VD) is given prior to aminolevulinate, a precursor (pro-drug) for protoporphyrin IX (PpIX), is an approach developed in our laboratory. We previously showed that 1α,25- dihydroxyvitamin D3 (calcitriol), given prior to PDT, enhances accumulation of PpIX and improves cell death post-PDT in a mouse skin cancer model. However, since calcitriol poses a risk for hypercalcemia, we replaced systemic calcitriol with oral cholecalciferol (D3), administered as a high (tenfold, "10K") diet over a ten-day period. Here, we ask whether VD deficiency might alter the response to cPDT. Nude mice were fed a VD-deficient diet for at least 4 weeks ("deficient"); controls were fed a normal 1,000 IU/kg diet ("1K"). Human A431 cells were implanted subcutaneously and mice were switched to the 10K diet or continued on their baseline diets (controls). In other experiments, mice received a human equivalent dose of 50,000 IU D3 by oral gavage, to simulate administration of a single, high-dose VD pill. At various times, tumors were harvested and serum was collected to measure levels of VD metabolic intermediates. A significant increase in PpIX levels and in the expression of differentiation and proliferation markers in tumor tissue was observed after VD supplementation of both the deficient and 1K mice. Further results describing mechanistic details of PpIX enhancement through alteration of heme- and VD-metabolic enzyme levels will be presented. Based on these results, a clinical study using oral vitamin D prior to PDT for human skin cancer should be performed.

  2. Vinyl-Deoxyadenosine in a Sarcin/Ricin RNA Loop and its Binding to Ricin Toxin A-Chain

    PubMed Central

    Roday, Setu; Saen-oon, Suwipa; Schramm, Vern L.

    2008-01-01

    8-Vinyl-2’-deoxyadenosine (8vdA) is a fluorophore with a quantum yield comparable to 2-aminopurine nucleoside. 8vdA was incorporated into a 10-mer stem-tetraloop RNA (8vdA-10) structure to characterize the properties of the base, 8-vinyladenine (8-vA), with respect to adenine as a substrate or inhibitor for ribosome inactivating proteins. Ricin Toxin A-chain (RTA) and Pokeweed Antiviral Protein (PAP) catalyze the release of adenine from a specific adenosine on a stem-tetraloop (GAGA) sequence at the elongation factor (eEF2) binding site of the 28S subunit of eukaryotic ribosomes, thereby arresting translation. RTA does not catalyze 8-vinyladenine release from 8vdA-10. Molecular dynamics simulations implicate a role for Arg 180 in oxacarbenium ion destabilization and lack of catalysis. However, 8vdA-10 is an active site analog and inhibits RTA with a Ki value of 2.4 μM. Adenine is also released from the second adenosine in the modified tetraloop demonstrating an alternative mode for the binding of this motif in the RTA active site. The 8vdA analog defines the specificities of RTA for the two adenylate depurination sites in an RNA substrate with a GAGA tetraloop. The rate of non-enzymatic acid-catalyzed solvolysis of 8-vinyladenine from the stem-loop RNA is described. Unlike RTA, PAP catalyzes the slow release of 8-vinyladenine from 8vdA-10. The isolation of 8-vA and its physicochemical characterization is described. PMID:17477546

  3. On the role of long range interactions for the adsorption of sexithiophene on Ag(110) surface

    SciTech Connect

    Matos, Jeronimo; Rojas, Tomas; Yildirim, Handan E-mail: Abdelkader.Kara@ucf.edu; Kara, Abdelkader E-mail: Abdelkader.Kara@ucf.edu

    2014-04-14

    The adsorption characteristics of the sexithiophene (6T) molecule on Ag(110) are studied using density functional theory with the inclusion of van der Waals (vdW) interactions. The stable adsorption configurations on 6T on Ag(110) as well as the nature of bonding the Ag substrate are evaluated. We also assess the performance of the vdW-DF method in describing the adsorption, energetics, heights, as well as the interface characteristics with the Ag(110) surface. We find two lowest adsorption energy configurations, at which the 6T molecule aligns with its molecular long axis parallel and perpendicular to the [001] direction, to be energetically close to each other, suggesting that they may coexist. Our findings indicate a significant increase in the 6T adsorption energies upon the inclusion of vdW interactions with the highest increase obtained using the opt-type functionals, in particular with the optB86b-vdW functional. The revPBE-vdW and rPW86-vdW2 functionals lead to less enhancement in adsorption energies that is attributed to the strong repulsive nature of these functionals, in agreement with earlier predictions. Upon adsorption of the 6T molecule, the changes in the atomic and electronic structures of the 6T molecule and Ag surface are found to be negligible; there is no charge transfer, and no interface state is observed. The work function is reduced upon adsorption with the largest change is ∼0.6 eV obtained using the optB88-vdW functional. The results are in good agreement with the available experimental observations of the adsorption configurations and the work function changes. Based on our results, we conclude that the nature of bonding for 6T on Ag(110) can be classified as strong physisorption.

  4. Does vaginal douching affect the type of candidal vulvovaginal infection?

    PubMed

    Shaaban, Omar M; Abbas, Ahmed M; Moharram, Ahmad M; Farhan, Mohammed M; Hassanen, Ibrahim H

    2015-11-01

    The normal vaginal microbiota is a dynamic system that continually fluctuates under the environmental changes and different physiological conditions. Yeast infections of the vagina are caused by one of the species of fungus called Candida (C.). The study aimed to evaluate the types of mycobiota in women with vulvovaginal candidiasis (VVC) who were performing vaginal douching (VD) or not. Furthermore, it studied the antifungal sensitivity toward different fungi isolated from the vagina. In a cross-sectional study conducted in Assiut University Hospital, Egypt, women with VVC were interviewed regarding relevant history including the habit of VD. Vaginal swabs were obtained and processed by direct microscope and by culture on CHROMagar Candida and other differential media. The types of Candida in women with the habit of VD were compared with those not having this habit. We found that VD habit was practiced by 67.4% of women with VVC, and Candida albicans was the commonest (78.3%) type observed. There was no significant difference in the percentage of non-albicans types between women performing VD (23.6%) and those not reporting this habit (18.9%). Harboring non-albicans types were significantly increased in regular performers of VD compared with those who had this procedure only after sexual intercourse or after the end of menstruation (36.8%,12.5%, and 16.7%, respectively) (P = .048). Thus, vaginal douching does not influence the type of Candida infection involved in VVC. Frequent performance of VD increases the likelihood of having non-albicans types and the resistance to the common antifungal agents. PMID:26129887

  5. Significant differences in the incidence of orofacial clefts in fifty-two Czech districts between 1983 and 1997.

    PubMed

    Peterka, M; Peterková, R; Tvrdek, M; Kuderová, J; Likovský, Z

    2000-01-01

    Between 1983 and 1997 a total of 2029 children with CL/P (cleft lip, cleft lip and palate or cleft palate), who were born in the Bohemian districts of the Czech Republic and who underwent surgery and treatment at the Clinic of Plastic Surgery in Prague, were analysed. One possibility for decreasing the risk of delivery of a child with CL/P is to decrease or eliminate its prenatal exposure to embryotoxic factors. Detection of the embryotoxic factors acting at the individual level (e.g. elevated temperature, drug consumption, x-ray examination or infection) is easier than the detection of embryotoxic factors operating at the population level (e.g. water contamination, air pollution). When searching for the latter factors, we first have to reveal regional differences in CL/P incidence. The aim of the present paper was to determine significant differences in the mean incidence of newborns with CL/P in Bohemian districts during a 15 year period. The correlation between the incidence of CL/P and the birth rate in the different districts was also examined. The mean incidence of CL/P in all Bohemian districts was 1.86 per 1000 newborns (1.86/1000). Districts were divided into three groups, according to significant differences in the incidence of CL/P using a confidence interval. The lowest mean incidence of CL/P was detected in the Svitavy district (0.72/1000) and Louny (1.05/1000). The highest mean incidence was found in the Beroun district (2.86/1000). Besides Beroun, a high mean incidence of CL/P (more than 1.96/1000) was also found in Klatovy, Mĕlník, Tábor, Kolín, Semily, Ceská Lípa, Pardubice, Teplice, Ceský Krumlov, Sokolov, Chomutov, Praha-západ, Jicín, Rakovník, Kladno, Prachatice, Rokycany, Tachov, Liberec, Pelhrimov. Paradoxically, the districts with a higher or lower birth rate exhibited a lower (1.62/1000) or higher (1.92/1000) incidence of CL/P, respectively. Future studies should elucidate whether the significant regional differences in the

  6. Purinergic contraction of the rat vas deferens in L-NAME-induced hypertension: effect of sildenafil

    PubMed Central

    Gur, Serap; Sikka, Suresh C.; Knight, Gillian E.; Burnstock, Geoffrey; Hellstrom, Wayne J.G.

    2010-01-01

    Hypertension (HTN) is a risk factor for erectile dysfunction, but its effect on vas deferens (VD) contractility and the ejaculatory response has not been delineated. NG-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor, was used for induction of nitric oxide (NO)-deficient HTN. Our aim was to evaluate the effects of L-NAME-induced HTN on rat VD contractility and to determine whether sildenafil affects VD contractility. A total of 36 male rats were divided into (1) control, (2) L-NAME–HTN, (3) sildenafil treated L-NAME–HTN groups. Group 2 was treated with L-NAME (40 mg kg-1 per day) in drinking water for 4 weeks. Group 3 received sildenafil (1.5 mg kg−1 per day, by oral gavage) concomitantly with L-NAME. The prostatic portion of the VD was subjected to electrical field stimulation (EFS, 1–20 Hz), and the P2X1 agonist α,β-methylene ATP (α,β-meATP, 100 μmol L−1–1 μmol L−1) and the α1-adrenoceptor agonist phenylephrine (Phe, 100 μmol L−1–1 mmol L−1) were used to construct concentration-response curves. These experiments were repeated in the presence of P2X receptor antagonist, pyridoxalphosphate-6-azophenyl-2′,4′-disulfonic acid (PPADS, 30 μmol L−1). VD contractions in response to EFS, α,β-meATP and Phe were significantly enhanced by L-NAME. Sildenafil treatment in the L-NAME group improved the contractile response of VD to EFS (20 Hz). In the presence of PPADS, the enhanced contractile response of VD to EFS and α,β-meATP in hypertensive rats was reversed. In the rat model of chronic NO depletion, the purinergic and adrenergic components and EFS affect VD contractility. The VD contractile response may be mediated more by the purinergic system than the adrenergic system, and sildenafil may alter the ejaculatory response in men with PE. PMID:20305675

  7. Development of polarizable models for molecular mechanical calculations. 4. van der Waals parametrization.

    PubMed

    Wang, Junmei; Cieplak, Piotr; Li, Jie; Cai, Qin; Hsieh, Meng-Juei; Luo, Ray; Duan, Yong

    2012-06-21

    In the previous publications of this series, we presented a set of Thole induced dipole interaction models using four types of screening functions. In this work, we document our effort to refine the van der Waals parameters for the Thole polarizable models. Following the philosophy of AMBER force field development, the van der Waals (vdW) parameters were tuned for the Thole model with linear screening function to reproduce both the ab initio interaction energies and the experimental densities of pure liquids. An in-house genetic algorithm was applied to maximize the fitness of "chromosomes" which is a function of the root-mean-square errors (RMSE) of interaction energy and liquid density. To efficiently explore the vdW parameter space, a novel approach was developed to estimate the liquid densities for a given vdW parameter set using the mean residue-residue interaction energies through interpolation/extrapolation. This approach allowed the costly molecular dynamics simulations be performed at the end of each optimization cycle only and eliminated the simulations during the cycle. Test results show notable improvements over the original AMBER FF99 vdW parameter set, as indicated by the reduction in errors of the calculated pure liquid densities (d), heats of vaporization (H(vap)), and hydration energies. The average percent error (APE) of the densities of 59 pure liquids was reduced from 5.33 to 2.97%; the RMSE of H(vap) was reduced from 1.98 to 1.38 kcal/mol; the RMSE of solvation free energies of 15 compounds was reduced from 1.56 to 1.38 kcal/mol. For the interaction energies of 1639 dimers, the overall performance of the optimized vdW set is slightly better than the original FF99 vdW set (RMSE of 1.56 versus 1.63 kcal/mol). The optimized vdW parameter set was also evaluated for the exponential screening function used in the Amoeba force field to assess its applicability for different types of screening functions. Encouragingly, comparable performance was

  8. High-Resolution Variable-Density 3D Cones Coronary MRA

    PubMed Central

    Addy, Nii Okai; Ingle, R. Reeve; Wu, Holden H.; Hu, Bob S.; Nishimura, Dwight G.

    2015-01-01

    Purpose To improve the spatial/temporal resolution of whole-heart coronary MR angiography (CMRA) by developing a variable-density (VD) 3D cones acquisition suitable for image reconstruction with parallel imaging and compressed sensing techniques. Methods A VD 3D cones trajectory design incorporates both radial and spiral trajectory undersampling techniques to achieve higher resolution. This design is used to generate a VD cones trajectory with 0.8 mm/66 ms isotropic spatial/temporal resolution, using a similar number of readouts as our previous fully sampled cones trajectory (1.2 mm/100 ms). Scans of volunteers and patients are performed to evaluate the performance of the VD trajectory, using non-Cartesian L1-ESPIRiT for high-resolution image reconstruction. Results With gridding reconstruction, the high-resolution scans experience an expected drop in signal-to-noise and contrast-to-noise ratios, but with L1-ESPIRiT, the apparent noise is substantially reduced. Compared to 1.2 mm images, in each volunteer, the L1-ESPIRiT 0.8 mm images exhibit higher vessel sharpness values in the right and left anterior descending arteries. Conclusion CMRA with isotropic sub-millimeter spatial resolution and high temporal resolution can be performed with VD 3D cones to improve the depiction of coronary arteries. PMID:26172829

  9. Correlation of polymorphism of APOE and LRP genes to cognitive impairment and behavioral and psychological symptoms of dementia in Alzheimer’s disease and vascular dementia

    PubMed Central

    Mou, Chengzhi; Han, Tao; Wang, Min; Jiang, Meng; Liu, Bin; Hu, Jia

    2015-01-01

    Objective: To discuss the correlation of polymorphism of APOE and LRP genes to cognitive impairment and behavioral and psychological symptoms of dementia (BPSD) in Alzheimer’s disease (AD) and vascular dementia (VD). Method: AD cases, VD cases and healthy control cases totaling 237, 255 and 234 were recruited, respectively. The mini-mental state examination (MMSE) was performed to evaluate cognitive impairment. Hamilton Depression Rating Scale (HAMD) and Hamilton Anxiety Scale (HAMA) were adopted to evaluate BPSD. Apolipoprotein E (APOE) and Low-density lipoprotein receptor-related protein gene (LRP) genotyping was carried out using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Results: (1) Frequencies of APOEε4 allele in AD group and VD group were significantly higher than that of the control (P<0.05); (2) MMSE scores of APOEε4 carriers in AD group and VD group were lower than that of non-APOEε4 carriers in the same group (P<0.05); (3) The proportion of APOEε4 carriers presenting with BPSD in AD group was considerably higher that of non-APOEε4 carriers (P<0.05). Conclusion: APOEε4 may be the common risk factor for cognitive impairment in AD and VD and the risk factor for BPSD in AD. PMID:26885125

  10. Supercurrent in van der Waals Josephson junction.

    PubMed

    Yabuki, Naoto; Moriya, Rai; Arai, Miho; Sata, Yohta; Morikawa, Sei; Masubuchi, Satoru; Machida, Tomoki

    2016-01-01

    Supercurrent flow between two superconductors with different order parameters, a phenomenon known as the Josephson effect, can be achieved by inserting a non-superconducting material between two superconductors to decouple their wavefunctions. These Josephson junctions have been employed in fields ranging from digital to quantum electronics, yet their functionality is limited by the interface quality and use of non-superconducting material. Here we show that by exfoliating a layered dichalcogenide (NbSe2) superconductor, the van der Waals (vdW) contact between the cleaved surfaces can instead be used to construct a Josephson junction. This is made possible by recent advances in vdW heterostructure technology, with an atomically flat vdW interface free of oxidation and inter-diffusion achieved by eliminating all heat treatment during junction preparation. Here we demonstrate that this artificially created vdW interface provides sufficient decoupling of the wavefunctions of the two NbSe2 crystals, with the vdW Josephson junction exhibiting a high supercurrent transparency.

  11. On the accuracy of van der Waals inclusive density-functional theory exchange-correlation functionals for ice at ambient and high pressures.

    PubMed

    Santra, Biswajit; Klimes, Jirí; Tkatchenko, Alexandre; Alfè, Dario; Slater, Ben; Michaelides, Angelos; Car, Roberto; Scheffler, Matthias

    2013-10-21

    Density-functional theory (DFT) has been widely used to study water and ice for at least 20 years. However, the reliability of different DFT exchange-correlation (xc) functionals for water remains a matter of considerable debate. This is particularly true in light of the recent development of DFT based methods that account for van der Waals (vdW) dispersion forces. Here, we report a detailed study with several xc functionals (semi-local, hybrid, and vdW inclusive approaches) on ice Ih and six proton ordered phases of ice. Consistent with our previous study [B. Santra, J. Klimeš, D. Alfè, A. Tkatchenko, B. Slater, A. Michaelides, R. Car, and M. Scheffler, Phys. Rev. Lett. 107, 185701 (2011)] which showed that vdW forces become increasingly important at high pressures, we find here that all vdW inclusive methods considered improve the relative energies and transition pressures of the high-pressure ice phases compared to those obtained with semi-local or hybrid xc functionals. However, we also find that significant discrepancies between experiment and the vdW inclusive approaches remain in the cohesive properties of the various phases, causing certain phases to be absent from the phase diagram. Therefore, room for improvement in the description of water at ambient and high pressures remains and we suggest that because of the stern test the high pressure ice phases pose they should be used in future benchmark studies of simulation methods for water. PMID:24160528

  12. Evolution of Moiré Profiles from van der Waals Superstructures of Boron Nitride Nanosheets.

    PubMed

    Liao, Yunlong; Cao, Wei; Connell, John W; Chen, Zhongfang; Lin, Yi

    2016-01-01

    Two-dimensional (2D) van der Waals (vdW) superstructures, or vdW solids, are formed by the precise restacking of 2D nanosheet lattices, which can lead to unique physical and electronic properties that are not available in the parent nanosheets. Moiré patterns formed by the crystalline mismatch between adjacent nanosheets are the most direct features for vdW superstructures under microscopic imaging. In this article, transmission electron microscopy (TEM) observation of hexagonal Moiré patterns with unusually large micrometer-sized lateral areas (up to ~1 μm(2)) and periodicities (up to ~50 nm) from restacking of liquid exfoliated hexagonal boron nitride nanosheets (BNNSs) is reported. This observation was attributed to the long range crystallinity and the contaminant-free surfaces of these chemically inert nanosheets. Parallel-line-like Moiré fringes with similarly large periodicities were also observed. The simulations and experiments unambiguously revealed that the hexagonal patterns and the parallel fringes originated from the same rotationally mismatched vdW stacking of BNNSs and can be inter-converted by simply tilting the TEM specimen following designated directions. This finding may pave the way for further structural decoding of other 2D vdW superstructure systems with more complex Moiré images. PMID:27188697

  13. The effect of positioning on the appearance of selected cranial thoracic structures in the dog.

    PubMed

    Kirberger, Robert M; Avner, Avi

    2006-01-01

    In this retrospective study the effect of thoracic positioning on the visibility and size of selected cranial thoracic structures in dogs was investigated. Dorsoventral (DV), ventrodorsal (VD) as well as left lateral recumbent (LLR) and right lateral recumbent (RLR) thoracic radiographs of 17 large, 15 medium, and 10 small skeletally mature dogs were evaluated. The craniodorsal and cranioventral mediastinum, the cupula pleura and sternal lymph nodes were examined. The effect of obesity was also evaluated. The craniodorsal mediastinum was better delineated on DV radiographs and was wider on VD radiographs. The craniodorsal mediastinal width: width of T2 cranial end-plate on VD radiographs was 2.41 for all groups combined and obesity significantly influenced this value. The cranioventral mediastinum was more visible in RLR and VD radiographs. A normal sternal lymph node soft tissue opacity was seen most commonly in RLR in large breed dogs and had a mean length of 30 mm. The pulmonary cupula extended beyond the first rib on all views and extended more cranially and was better visualised on VD than DV views.

  14. Temperature and meal size effects on the postprandial metabolism and energetics in a boid snake.

    PubMed

    Toledo, Luís Felipe; Abe, Augusto S; Andrade, Denis V

    2003-01-01

    We investigated the combined effect of meal size and temperature on the aerobic metabolism and energetics of digestion in Boa constrictor amarali. Oxygen uptake rates (Vd2;o2) and the duration of the digestion were determined in snakes fed with meals equaling to 5%, 10%, 20%, and 40% of the snake's body mass at 25 degrees and 30 degrees C. The maximum Vd2;o2 values attained during digestion were greater at 30 degrees C than at 25 degrees C. Both maximal Vd2;o2 values and the duration of the specific dynamic action (SDA) were attained sooner at 30 degrees C than at 25 degrees C. Therefore, the temperature effect on digestion in Boa is characterized by the shortening of the SDA duration at the expense of increased Vd2;o2. Energy allocated to SDA was not affected by meal size but was greater at 25 degrees C compared to 30 degrees C. This indicates that a postprandial thermophilic response can be advantageous not only by decreasing the duration of digestion but also by improving digestive efficiency. Maximal Vd2;o2 and SDA duration increased with meal size at both temperatures.

  15. Van Der Waals-Corrected Density Functional Theory Simulation of Adsorption Processes on Noble-Metal Surfaces: Xe on Ag(111), Au(111), and Cu(111)

    NASA Astrophysics Data System (ADS)

    Silvestrelli, Pier Luigi; Ambrosetti, Alberto

    2016-10-01

    The DFT/vdW-WF2s1 method based on the generation of localized Wannier functions, recently developed to include the van der Waals interactions in the density functional theory and describe adsorption processes on metal surfaces by taking metal-screening effects into account, is applied to the case of the interaction of Xe with noble-metal surfaces, namely Ag(111), Au(111), and Cu(111). The study is also repeated by adopting the DFT/vdW-QHO-WF variant relying on the quantum harmonic oscillator model which describes well many body effects. Comparison of the computed equilibrium binding energies and distances, and the C_3 coefficients characterizing the adatom-surface van der Waals interactions, with available experimental and theoretical reference data shows that the methods perform well and elucidates the importance of properly including screening effects. The results are also compared with those obtained by other vdW-corrected DFT schemes, including PBE-D, vdW-DF, vdW-DF2, rVV10, and by the simpler local density approximation and semi-local (PBE) generalized gradient approximation approaches.

  16. Assessing the influence of van der Waals corrected exchange-correlation functionals on the anisotropic mechanical properties of coinage metals

    NASA Astrophysics Data System (ADS)

    Lee, Ji-Hwan; Park, Jong-Hun; Soon, Aloysius

    2016-07-01

    Current materials-related calculations employ density-functional theory (DFT), commonly using the (semi-)local-density approximations for the exchange-correlation (xc) functional. The difficulties in arriving at a reasonable description of van der Waals (vdW) interactions by DFT-based models is to date a big challenge. In this work, we use various flavors of vdW-corrected DFT xc functionals—ranging from the quasiempirical force-field add-on vdW corrections to self-consistent nonlocal correlation functionals—to study the bulk lattice and mechanical properties (including the elastic constants and anisotropic indices) of the coinage metals (copper, silver, and gold). We critically assess the reliability of the different vdW-corrected DFT methods in describing their anisotropic mechanical properties which have been less reported in the literature. In the context of this work, we regard that our results reiterate the fact that advocating a so-called perfect vdW-inclusive xc functional for describing the general physics and chemistry of these coinage metals could be a little premature. These challenges to modern-day functionals for anisotropically strained coinage metals (e.g., at the faceted surfaces of nanostructures) may well be relevant to other strained material systems.

  17. Primary hyperparathyroidism and vitamin D deficiency.

    PubMed

    Vélayoudom-Céphise, Fritz-Line; Wémeau, Jean-Louis

    2015-05-01

    Primary hyperparathyroidism (PHPT) and vitamin D (VD) deficiency are frequent conditions due to the widespread application of assays for calcium and VD. PHPT presentation is dominated by diversity in its expression and the current predominance of asymptomatic forms. VD, which plays a major role in calcium and phosphate homeostasis, is also involved in many physiological processes in this disease, such as lipid and glucose metabolism, and in the signalling pathways and functioning of many cell types. The bone and cardiometabolic complications described in PHPT are exacerbated by vitamin D deficiency, the prevalence of which varies according to many parameters (environment, skin pigmentation, associated chronic diseases, liver and kidney function, assay kit used, etc.). In response to this observation, experts in field from medical societies validated the indication for systematic assay of VD occurring with PHPT and the need for replacement in case of deficiency. Several epidemiological studies have confirmed that replacement with natural vitamin D is well tolerated and safe in subjects with PHPT and VD deficiency. This supplementation reduces hyperparathormonemia, does not have symptomatic effects on calciuria, and especially improves the bone and functional condition of patients.

  18. Ligand selectivity in tachykinin and natalisin neuropeptidergic systems of the honey bee parasitic mite Varroa destructor

    PubMed Central

    Jiang, Hongbo; Kim, Donghun; Dobesh, Sharon; Evans, Jay D.; Nachman, Ronald J.; Kaczmarek, Krzysztof; Zabrocki, Janusz; Park, Yoonseong

    2016-01-01

    The varroa mite, Varroa destructor, is a devastating ectoparasite of the honey bees Apis mellifera and A. cerana. Control of these mites in beehives is a challenge in part due to the lack of toxic agents that are specific to mites and not to the host honey bee. In searching for a specific toxic target of varroa mites, we investigated two closely related neuropeptidergic systems, tachykinin-related peptide (TRP) and natalisin (NTL), and their respective receptors. Honey bees lack both NTL and the NTL receptor in their genome sequences, providing the rationale for investigating these receptors to understand their specificities to various ligands. We characterized the receptors for NTL and TRP of V. destructor (VdNTL-R and VdTRP-R, respectively) and for TRP of A. mellifera (AmTRP-R) in a heterologous reporter assay system to determine the activities of various ligands including TRP/NTL peptides and peptidomimetics. Although we found that AmTRP-R is highly promiscuous, activated by various ligands including two VdNTL peptides when a total of 36 ligands were tested, we serendipitously found that peptides carrying the C-terminal motif -FWxxRamide are highly specific to VdTRP-R. This motif can serve as a seed sequence for designing a VdTRP-R-specific agonist. PMID:26817786

  19. Can Transcutaneous CO2 Tension Be Used to Calculate Ventilatory Dead Space? A Pilot Study

    PubMed Central

    Geeti, Adiba A.; Darr, Umer M.; Kaufman, David A.

    2016-01-01

    Dead space fraction (Vd/Vt) measurement performed using volumetric capnography requires arterial blood gas (ABG) sampling to estimate the partial pressure of carbon dioxide (PaCO2). In recent years, transcutaneous capnography (PtcCO2) has emerged as a noninvasive method of estimating PaCO2. We hypothesized that PtcCO2 can be used as a substitute for PaCO2 in the calculation of Vd/Vt. In this prospective pilot comparison study, 30 consecutive postcardiac surgery mechanically ventilated patients had Vd/Vt calculated separately using volumetric capnography by substituting PtcCO2 for PaCO2. The mean Vd/Vt calculated using PaCO2 and PtcCO2 was 0.48 ± 0.09 and 0.53 ± 0.08, respectively, with a strong positive correlation between the two methods of calculation (Pearson's correlation = 0.87, p < 0.05). Bland-Altman analysis showed a mean difference of −0.05 (95% CI: −0.01 to −0.09) between the two methods. PtcCO2 measurements can provide a noninvasive means to measure Vd/Vt, thus accessing important physiologic information and prognostic assessment in patients receiving mechanical ventilation. PMID:27688911

  20. A van der Waals density functional theory comparison of metal decorated graphene systems for hydrogen adsorption

    NASA Astrophysics Data System (ADS)

    Wong, Janet; Yadav, Shwetank; Tam, Jasmine; Veer Singh, Chandra

    2014-06-01

    Previous Density Functional Theory (DFT) studies on metal decorated graphene generally use local density approximation (LDA) or generalized gradient approximation (GGA) functionals which can cause inaccuracies in hydrogen binding energies as they neglect van der Waals (vdW) interactions and are difficult to compare due to their widely varying simulation parameters. We investigated the hydrogen binding ability of several metals with a consistent set of simulations using the GGA functional and incorporated vdW forces through the vdW-DF2 functional. Metal adatom anchoring on graphene and hydrogen adsorption ability for both single and double sided decoration were studied for eight metals (Al, Li, Na, Ca, Cu, Ni, Pd, and Pt). It was found that the vdW correction can have a significant impact on both metal and hydrogen binding energies. The vdW-DF2 functional led to stronger metal adatom and hydrogen binding for light metals in comparison to GGA results, while heavier transition metals displayed the opposite behaviour but still produced stronger hydrogen binding energies than light metals. Nickel was found to be the best balance between hydrogen binding ability for reversible storage and low weight. The effects on hydrogen binding energy and maximum achievable hydrogen gravimetric density were analyzed for Ni-graphene systems with varying metal coverage. Lower metal coverage was found to improve hydrogen binding but decrease hydrogen gravimetric density. The highest achieved Ni-graphene system gravimetric density was 6.12 wt. %.

  1. Evolution of Moiré Profiles from van der Waals Superstructures of Boron Nitride Nanosheets.

    PubMed

    Liao, Yunlong; Cao, Wei; Connell, John W; Chen, Zhongfang; Lin, Yi

    2016-01-01

    Two-dimensional (2D) van der Waals (vdW) superstructures, or vdW solids, are formed by the precise restacking of 2D nanosheet lattices, which can lead to unique physical and electronic properties that are not available in the parent nanosheets. Moiré patterns formed by the crystalline mismatch between adjacent nanosheets are the most direct features for vdW superstructures under microscopic imaging. In this article, transmission electron microscopy (TEM) observation of hexagonal Moiré patterns with unusually large micrometer-sized lateral areas (up to ~1 μm(2)) and periodicities (up to ~50 nm) from restacking of liquid exfoliated hexagonal boron nitride nanosheets (BNNSs) is reported. This observation was attributed to the long range crystallinity and the contaminant-free surfaces of these chemically inert nanosheets. Parallel-line-like Moiré fringes with similarly large periodicities were also observed. The simulations and experiments unambiguously revealed that the hexagonal patterns and the parallel fringes originated from the same rotationally mismatched vdW stacking of BNNSs and can be inter-converted by simply tilting the TEM specimen following designated directions. This finding may pave the way for further structural decoding of other 2D vdW superstructure systems with more complex Moiré images.

  2. Can Transcutaneous CO2 Tension Be Used to Calculate Ventilatory Dead Space? A Pilot Study

    PubMed Central

    Geeti, Adiba A.; Darr, Umer M.; Kaufman, David A.

    2016-01-01

    Dead space fraction (Vd/Vt) measurement performed using volumetric capnography requires arterial blood gas (ABG) sampling to estimate the partial pressure of carbon dioxide (PaCO2). In recent years, transcutaneous capnography (PtcCO2) has emerged as a noninvasive method of estimating PaCO2. We hypothesized that PtcCO2 can be used as a substitute for PaCO2 in the calculation of Vd/Vt. In this prospective pilot comparison study, 30 consecutive postcardiac surgery mechanically ventilated patients had Vd/Vt calculated separately using volumetric capnography by substituting PtcCO2 for PaCO2. The mean Vd/Vt calculated using PaCO2 and PtcCO2 was 0.48 ± 0.09 and 0.53 ± 0.08, respectively, with a strong positive correlation between the two methods of calculation (Pearson's correlation = 0.87, p < 0.05). Bland-Altman analysis showed a mean difference of −0.05 (95% CI: −0.01 to −0.09) between the two methods. PtcCO2 measurements can provide a noninvasive means to measure Vd/Vt, thus accessing important physiologic information and prognostic assessment in patients receiving mechanical ventilation.

  3. Internal anatomy and ultrastructure of the male reproductive system of the spider crab Maja brachydactyla (Decapoda: Brachyura).

    PubMed

    Simeó, C G; Ribes, E; Rotllant, G

    2009-10-01

    The morphology and function of the male reproductive system in the spider crab Maja brachydactyla, an important commercial species, is described using light and electron microscopy. The reproductive system follows the pattern found among brachyuran with several peculiarities. The testis, known as tubular testis, consists of a single, highly coiled seminiferous tubule divided all along by an inner epithelium into germinal, transformation, and evacuation zones, each playing a different role during spermatogenesis. The vas deferens (VD) presents diverticula increasing in number and size towards the median VD, where spermatophores are stored. The inner monostratified epithelium exocytoses the materials involved in the spermatophore wall formation (named substance I and II) and spermatophore storage in the anterior and median VD, respectively. A large accessory gland is attached to the posterior VD, and its secretions are released as granules in apocrine secretion, and stored in the lumen of the diverticula as seminal fluids. A striated musculature may contribute to the formation and movement of spermatophores and seminal fluids along the VD. The ejaculatory duct (ED) shows a multilayered musculature and a nonsecretory pseudostratified epithelium, and extrudes the reproductive products towards the gonopores. A tissue attached to the ED is identified as the androgenic gland.

  4. Increased circulating VCAM-1 correlates with advanced disease and poor survival in patients with multiple myeloma: reduction by post-bortezomib and lenalidomide treatment

    PubMed Central

    Terpos, E; Migkou, M; Christoulas, D; Gavriatopoulou, M; Eleutherakis-Papaiakovou, E; Kanellias, N; Iakovaki, M; Panagiotidis, I; Ziogas, D C; Fotiou, D; Kastritis, E; Dimopoulos, M A

    2016-01-01

    Circulating vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1) and selectins were prospectively measured in 145 newly-diagnosed patients with symptomatic myeloma (NDMM), 61 patients with asymptomatic/smoldering myeloma (SMM), 47 with monoclonal gammopathy of undetermined significance (MGUS) and 87 multiple myeloma (MM) patients at first relapse who received lenalidomide- or bortezomib-based treatment (RD, n=47; or VD, n=40). Patients with NDMM had increased VCAM-1 and ICAM-1 compared with MGUS and SMM patients. Elevated VCAM-1 correlated with ISS-3 and was independently associated with inferior overall survival (OS) (45 months for patients with VCAM-1 >median vs 75 months, P=0.001). MM patients at first relapse had increased levels of ICAM-1 and L-selectin, even compared with NDMM patients and had increased levels of VCAM-1 compared with MGUS and SMM. Both VD and RD reduced dramatically serum VCAM-1 after four cycles of therapy, but only VD reduced serum ICAM-1, irrespective of response to therapy. The reduction of VCAM-1 was more pronounced after RD than after VD. Our study provides evidence for the prognostic value of VCAM-1 in myeloma patients, suggesting that VCAM-1 could be a suitable target for the development of anti-myeloma therapies. Furthermore, the reduction of VCAM-1 and ICAM-1 by RD and VD supports the inhibitory effect of these drugs on the adhesion of MM cells to stromal cells. PMID:27232930

  5. Increased circulating VCAM-1 correlates with advanced disease and poor survival in patients with multiple myeloma: reduction by post-bortezomib and lenalidomide treatment.

    PubMed

    Terpos, E; Migkou, M; Christoulas, D; Gavriatopoulou, M; Eleutherakis-Papaiakovou, E; Kanellias, N; Iakovaki, M; Panagiotidis, I; Ziogas, D C; Fotiou, D; Kastritis, E; Dimopoulos, M A

    2016-01-01

    Circulating vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1) and selectins were prospectively measured in 145 newly-diagnosed patients with symptomatic myeloma (NDMM), 61 patients with asymptomatic/smoldering myeloma (SMM), 47 with monoclonal gammopathy of undetermined significance (MGUS) and 87 multiple myeloma (MM) patients at first relapse who received lenalidomide- or bortezomib-based treatment (RD, n=47; or VD, n=40). Patients with NDMM had increased VCAM-1 and ICAM-1 compared with MGUS and SMM patients. Elevated VCAM-1 correlated with ISS-3 and was independently associated with inferior overall survival (OS) (45 months for patients with VCAM-1 >median vs 75 months, P=0.001). MM patients at first relapse had increased levels of ICAM-1 and L-selectin, even compared with NDMM patients and had increased levels of VCAM-1 compared with MGUS and SMM. Both VD and RD reduced dramatically serum VCAM-1 after four cycles of therapy, but only VD reduced serum ICAM-1, irrespective of response to therapy. The reduction of VCAM-1 was more pronounced after RD than after VD. Our study provides evidence for the prognostic value of VCAM-1 in myeloma patients, suggesting that VCAM-1 could be a suitable target for the development of anti-myeloma therapies. Furthermore, the reduction of VCAM-1 and ICAM-1 by RD and VD supports the inhibitory effect of these drugs on the adhesion of MM cells to stromal cells. PMID:27232930

  6. Cerebrovascular Diseases in Workers at Mayak PA: The Difference in Radiation Risk between Incidence and Mortality.

    PubMed

    Simonetto, Cristoforo; Schöllnberger, Helmut; Azizova, Tamara V; Grigoryeva, Evgenia S; Pikulina, Maria V; Eidemüller, Markus

    2015-01-01

    A detailed analysis of cerebrovascular diseases (CeVD) for the cohort of workers at Mayak Production Association (PA) is presented. This cohort is especially suitable for the analysis of radiation induced circulatory diseases, due to the detailed medical surveillance and information on several risk factors. The risk after external, typically protracted, gamma exposure is analysed, accounting for potential additional internal alpha exposure. Three different endpoints have been investigated: incidence and mortality from all cerebrovascular diseases and incidence of stroke. Particular emphasis was given to the form of the dose-response relationship and the time dependence of the radiation induced risk. Young attained age was observed to be an important, aggravating modifier of radiation risk for incidence of CeVD and stroke. For incidence of CeVD, our analysis supports a dose response sub-linear for low doses. Finally, the excess relative risk per dose was confirmed to be significantly higher for incidence of CeVD compared to CeVD mortality and incidence of stroke. Arguments are presented for this difference to be based on a true biological effect. PMID:25933038

  7. Spatially Correlated Disorder in Epitaxial van der Waals Heterostructures

    NASA Astrophysics Data System (ADS)

    Laanait, Nouamane; Zhang, Zhan; Schleputz, Christian; Liu, Ying; Wojcik, Michael; Myers-Ward, Rachael; Gaskill, D. Kurt; Fenter, Paul; Li, Lian

    The structural cohesion of van der Waals (vdW) heterostructures relies upon a cooperative balance between strong intra-layer bonded interactions and weak inter-layer coupling. The confinement of extended defects to within a single vdW layer and competing interactions introduced by epitaxial constraints could generate fundamentally new structural disorders. Here we report on the presence of spatially correlated and localized disorder states that coexist with the near perfect crystallographic order along the growth direction of epitaxial vdW heterostructure of Bi2Se3/graphene/SiC grown by molecular beam epitaxy. With the depth penetration of hard X-ray diffraction microscopy and high-resolution surface scattering, we imaged local structural configurations from the atomic to mesoscopic length scales, and found that these disorder states result as a confluence of atomic scale modulations in the strength of vdW layer-layer interactions and nanoscale boundary conditions imposed by the substrate. These findings reveal a vast landscape of novel disorder states that can be manifested in epitaxial vdW heterostructures. Supported by the Wigner Fellowship program at Oak Ridge Nat'l Lab.

  8. Induction of differentiation of myelogenous leukemia cells by humulone, a bitter in the hop.

    PubMed

    Honma, Y; Tobe, H; Makishima, M; Yokoyama, A; Okabe-Kado, J

    1998-07-01

    The active form of vitamin D, 1alpha,25-dihydroxyvitamin D3 (VD3), inhibits proliferation and induces differentiation of myelomonocytic leukemia cells, but its clinical use is limited by the adverse effect of hypercalcemia. VD3 mobilizes calcium stores from bone by inducing the dissolution of bone mineral and matrix. We have recently found that humulone, a bitter in the hop extract for beer brewing, effectively inhibits bone resorption. In this study we examined the effect of humulone on the differentiation of human myelogenous leukemia cells. Humulone alone inhibited the growth of monoblastic leukemia U937 cells while only slightly increasing differentiation markers such as nitroblue tetrazolium (NBT)-reducing and lysozyme activities. Humulone effectively enhanced the differentiation-inducing action of VD3. Other myelomonocytic leukemia cells were induced to differentiate by VD3 and this was also enhanced by humulone. Since humulone is a less-toxic inhibitor of bone resorption, the combination of humulone and VD3 may be useful in differentiation therapy of myelomonocytic leukemia.

  9. The role of van der Waals interactions in the adsorption of noble gases on metal surfaces

    SciTech Connect

    Chen, De-Li; Al-Saidi, W A; Johnson, J Karl

    2012-10-03

    Adsorption of noble gases on metal surfaces is determined by weak interactions. We applied two versions of the nonlocal van der Waals density functional (vdW-DF) to compute adsorption energies of Ar, Kr, and Xe on Pt(111), Pd(111), Cu(111), and Cu(110) metal surfaces. We have compared our results with data obtained using other density functional approaches, including the semiempirical vdW corrected DFT-D2. The vdW-DF results show considerable improvements in the description of adsorption energies and equilibrium distances over other DFTbased methods, giving good agreement with experiments. We have also calculated perpendicular vibrational energies for noble gases on the metal surfaces using vdWDF data and found excellent agreement with available experimental results. Our vdW-DF calculations show that adsorption of noble gases on low-coordination sites is energetically favored over high-coordination sites, but only by a few meV. Analysis of the 2-dimensional potential energy surface shows that the high-coordination sites are local maxima on the 2-dimensional potential energy surface and therefore unlikely to be observed in experiments, which provides an explanation of the experimental observations. The DFT-D2 approach with the standard parameterization was found to overestimate the dispersion interactions, and to give the wrong adsorption site preference for four of the nine systems we studied.

  10. Cohesive properties of noble metals by van der Waals-corrected density functional theory: Au, Ag, and Cu as case studies

    NASA Astrophysics Data System (ADS)

    Ambrosetti, Alberto; Silvestrelli, Pier Luigi

    2016-07-01

    The cohesive energy, equilibrium lattice constant, and bulk modulus of Au, Ag, and Cu noble metals are computed by different van der Waals (vdW)-corrected density functional theory (DFT) methods, including vdW-DF, vdW-DF2, vdW-DF-cx, rVV10, and PBE-D. Two specifically designed methods are also developed in order to effectively include dynamical screening effects: the DFT/vdW-WF2p method, based on the generation of maximally localized Wannier functions, and the RPAp scheme (in two variants), based on a single-oscillator model of the localized electron response. Comparison with results obtained without explicit inclusion of van der Waals effects, such as with the local density approximation (LDA), PBE, PBEsol, or the hybrid PBE0 functional, elucidates the importance of a suitable description of screened van der Waals interactions even in the case of strong metal bonding. Many-body effects are also quantitatively evaluated within the RPAp approach.

  11. Evolution of Moiré Profiles from van der Waals Superstructures of Boron Nitride Nanosheets

    PubMed Central

    Liao, Yunlong; Cao, Wei; Connell, John W.; Chen, Zhongfang; Lin, Yi

    2016-01-01

    Two-dimensional (2D) van der Waals (vdW) superstructures, or vdW solids, are formed by the precise restacking of 2D nanosheet lattices, which can lead to unique physical and electronic properties that are not available in the parent nanosheets. Moiré patterns formed by the crystalline mismatch between adjacent nanosheets are the most direct features for vdW superstructures under microscopic imaging. In this article, transmission electron microscopy (TEM) observation of hexagonal Moiré patterns with unusually large micrometer-sized lateral areas (up to ~1 μm2) and periodicities (up to ~50 nm) from restacking of liquid exfoliated hexagonal boron nitride nanosheets (BNNSs) is reported. This observation was attributed to the long range crystallinity and the contaminant-free surfaces of these chemically inert nanosheets. Parallel-line-like Moiré fringes with similarly large periodicities were also observed. The simulations and experiments unambiguously revealed that the hexagonal patterns and the parallel fringes originated from the same rotationally mismatched vdW stacking of BNNSs and can be inter-converted by simply tilting the TEM specimen following designated directions. This finding may pave the way for further structural decoding of other 2D vdW superstructure systems with more complex Moiré images. PMID:27188697

  12. Supercurrent in van der Waals Josephson junction

    PubMed Central

    Yabuki, Naoto; Moriya, Rai; Arai, Miho; Sata, Yohta; Morikawa, Sei; Masubuchi, Satoru; Machida, Tomoki

    2016-01-01

    Supercurrent flow between two superconductors with different order parameters, a phenomenon known as the Josephson effect, can be achieved by inserting a non-superconducting material between two superconductors to decouple their wavefunctions. These Josephson junctions have been employed in fields ranging from digital to quantum electronics, yet their functionality is limited by the interface quality and use of non-superconducting material. Here we show that by exfoliating a layered dichalcogenide (NbSe2) superconductor, the van der Waals (vdW) contact between the cleaved surfaces can instead be used to construct a Josephson junction. This is made possible by recent advances in vdW heterostructure technology, with an atomically flat vdW interface free of oxidation and inter-diffusion achieved by eliminating all heat treatment during junction preparation. Here we demonstrate that this artificially created vdW interface provides sufficient decoupling of the wavefunctions of the two NbSe2 crystals, with the vdW Josephson junction exhibiting a high supercurrent transparency. PMID:26830754

  13. Passivation of CdSe Quantum Dots by Graphene and MoS2 Monolayer Encapsulation

    NASA Astrophysics Data System (ADS)

    Zhang, Datong; Wang, Dennis Zi-Ren; Creswell, Richard C.; Lu, Chenguang; Herman, Irving P.

    The encapsulation of a monolayer of CdSe quantum dots (QDs) by one-to-three layer graphene and MoS2 sheets protects the QDs from oxidation. Photoluminescence (PL) from the QD cores shows a much slower decrease in core diameter over time due to slower oxidation in regions where the QDs are covered by van der Waals (vdW) layers than in those where they are not, for chips stored both in the dark and in the presence of light. PL mapping shows that the CdSe QDs under the central part of the vdW sheet age slower than those near its edges, because oxidation of the covered QDs is limited by transport of oxygen from the edges of the vdW sheets and not transport across the vdW layers. This encapsulation effect is also tested with other environments. Preliminary results show that vdW materials could be promising candidates for nano-coating materials for devices operating in extreme environments.

  14. Rannasangpei Is a Therapeutic Agent in the Treatment of Vascular Dementia

    PubMed Central

    Wu, Peng; Luo, Yuandai; Zhen, Lifang; Hu, Xianda; Shang, Ying; Liao, Yinuo; Xue, Huiyuan; Huang, Fukai; Xiao, Wei

    2016-01-01

    Rannasangpei (RSNP) is used as a therapeutic agent in the treatment of cardiovascular diseases, neurological disorders, and neurodegeneration in China; however, its potential use in the treatment of vascular dementia (VD) was unclear. In this study, our aim was to examine the neuroprotective effect of RSNP in a VD rat model, which was induced by permanent bilateral common carotid artery occlusion (2VO). Four-week administration with two doses of RSNP was investigated in our study. Severe cognitive deficit in the VD model, which was confirmed in Morris water maze (MWM) test, was significantly restored by the administration of RSNP. ELISA revealed that the treatments with both doses of RSNP could reinstate the cholinergic activity in the VD animals by elevating the production of choline acetyltransferase (ChAT) and reducing the acetylcholinesterase (AChE); the treatment of RSNP could also reboot the level of superoxide dismutase (SOD) and decrease malondialdehyde (MDA). Moreover, Western blot and quantitative PCR (Q-PCR) results indicated that the RSNP could suppress the apoptosis in the hippocampus of the VD animals by increasing the expression ratio of B-cell lymphoma-2 (Bcl-2) to Bcl-2-associated X protein (Bax). These results suggested that RSNP might be a therapeutic agent in the treatment of vascular dementia in the future. PMID:27293454

  15. Cerebrovascular Diseases in Workers at Mayak PA: The Difference in Radiation Risk between Incidence and Mortality

    PubMed Central

    Simonetto, Cristoforo; Schöllnberger, Helmut; Azizova, Tamara V.; Grigoryeva, Evgenia S.; Pikulina, Maria V.; Eidemüller, Markus

    2015-01-01

    A detailed analysis of cerebrovascular diseases (CeVD) for the cohort of workers at Mayak Production Association (PA) is presented. This cohort is especially suitable for the analysis of radiation induced circulatory diseases, due to the detailed medical surveillance and information on several risk factors. The risk after external, typically protracted, gamma exposure is analysed, accounting for potential additional internal alpha exposure. Three different endpoints have been investigated: incidence and mortality from all cerebrovascular diseases and incidence of stroke. Particular emphasis was given to the form of the dose-response relationship and the time dependence of the radiation induced risk. Young attained age was observed to be an important, aggravating modifier of radiation risk for incidence of CeVD and stroke. For incidence of CeVD, our analysis supports a dose response sub-linear for low doses. Finally, the excess relative risk per dose was confirmed to be significantly higher for incidence of CeVD compared to CeVD mortality and incidence of stroke. Arguments are presented for this difference to be based on a true biological effect. PMID:25933038

  16. Density functional study of 1,3,5-trinitro-1,3,5-triazine molecular crystal with van der Waals interactions.

    PubMed

    Shimojo, Fuyuki; Wu, Zhongqing; Nakano, Aiichiro; Kalia, Rajiv K; Vashishta, Priya

    2010-03-01

    Volume dependence of the total energy and vibrational properties of crystalline l,3,5-trinitro-l,3,5-triazine (RDX) are calculated using the density functional theory (DFT). For this molecular crystal, properties calculated with a generalized gradient approximation to the exchange-correlation energy differ drastically from experimental values. This discrepancy arises from the inadequacy in treating weak van der Waals (vdW) interactions between molecules in the crystal, and an empirical vdW correction to DFT (DFT-D approach by Grimme) is shown to account for the dispersion effects accurately for the RDX crystal, while incurring little computational overhead. The nonempirical van der Waals density-functional (vdW-DF) method also provides an accurate description of the vdW corrections but with orders-of-magnitude more computation. We find that the vibrational properties of RDX are affected in a nontrivial manner by the vdW correction due to its dual role--reduction of the equilibrium volume and additional atomic forces.

  17. On the accuracy of van der Waals inclusive density-functional theory exchange-correlation functionals for ice at ambient and high pressures

    NASA Astrophysics Data System (ADS)

    Santra, Biswajit; Klimeš, Jiří; Tkatchenko, Alexandre; Alfè, Dario; Slater, Ben; Michaelides, Angelos; Car, Roberto; Scheffler, Matthias

    2013-10-01

    Density-functional theory (DFT) has been widely used to study water and ice for at least 20 years. However, the reliability of different DFT exchange-correlation (xc) functionals for water remains a matter of considerable debate. This is particularly true in light of the recent development of DFT based methods that account for van der Waals (vdW) dispersion forces. Here, we report a detailed study with several xc functionals (semi-local, hybrid, and vdW inclusive approaches) on ice Ih and six proton ordered phases of ice. Consistent with our previous study [B. Santra, J. Klimeš, D. Alfè, A. Tkatchenko, B. Slater, A. Michaelides, R. Car, and M. Scheffler, Phys. Rev. Lett. 107, 185701 (2011)] which showed that vdW forces become increasingly important at high pressures, we find here that all vdW inclusive methods considered improve the relative energies and transition pressures of the high-pressure ice phases compared to those obtained with semi-local or hybrid xc functionals. However, we also find that significant discrepancies between experiment and the vdW inclusive approaches remain in the cohesive properties of the various phases, causing certain phases to be absent from the phase diagram. Therefore, room for improvement in the description of water at ambient and high pressures remains and we suggest that because of the stern test the high pressure ice phases pose they should be used in future benchmark studies of simulation methods for water.

  18. On the accuracy of van der Waals inclusive density-functional theory exchange-correlation functionals for ice at ambient and high pressures.

    PubMed

    Santra, Biswajit; Klimes, Jirí; Tkatchenko, Alexandre; Alfè, Dario; Slater, Ben; Michaelides, Angelos; Car, Roberto; Scheffler, Matthias

    2013-10-21

    Density-functional theory (DFT) has been widely used to study water and ice for at least 20 years. However, the reliability of different DFT exchange-correlation (xc) functionals for water remains a matter of considerable debate. This is particularly true in light of the recent development of DFT based methods that account for van der Waals (vdW) dispersion forces. Here, we report a detailed study with several xc functionals (semi-local, hybrid, and vdW inclusive approaches) on ice Ih and six proton ordered phases of ice. Consistent with our previous study [B. Santra, J. Klimeš, D. Alfè, A. Tkatchenko, B. Slater, A. Michaelides, R. Car, and M. Scheffler, Phys. Rev. Lett. 107, 185701 (2011)] which showed that vdW forces become increasingly important at high pressures, we find here that all vdW inclusive methods considered improve the relative energies and transition pressures of the high-pressure ice phases compared to those obtained with semi-local or hybrid xc functionals. However, we also find that significant discrepancies between experiment and the vdW inclusive approaches remain in the cohesive properties of the various phases, causing certain phases to be absent from the phase diagram. Therefore, room for improvement in the description of water at ambient and high pressures remains and we suggest that because of the stern test the high pressure ice phases pose they should be used in future benchmark studies of simulation methods for water.

  19. Versatile van der Waals Density Functional Based on a Meta-Generalized Gradient Approximation

    NASA Astrophysics Data System (ADS)

    Peng, Haowei; Yang, Zeng-Hui; Perdew, John P.; Sun, Jianwei

    2016-10-01

    A "best-of-both-worlds" van der Waals (vdW) density functional is constructed, seamlessly supplementing the strongly constrained and appropriately normed (SCAN) meta-generalized gradient approximation for short- and intermediate-range interactions with the long-range vdW interaction from r VV 10 , the revised Vydrov-van Voorhis nonlocal correlation functional. The resultant SCAN +r VV 10 is the only vdW density functional to date that yields excellent interlayer binding energies and spacings, as well as intralayer lattice constants in 28 layered materials. Its versatility for various kinds of bonding is further demonstrated by its good performance for 22 interactions between molecules; the cohesive energies and lattice constants of 50 solids; the adsorption energy and distance of a benzene molecule on coinage-metal surfaces; the binding energy curves for graphene on Cu(111), Ni(111), and Co(0001) surfaces; and the rare-gas solids. We argue that a good semilocal approximation should (as SCAN does) capture the intermediate-range vdW through its exchange term. We have found an effective range of the vdW interaction between 8 and 16 Å for systems considered here, suggesting that this interaction is negligibly small at the larger distances where it reaches its asymptotic power-law decay.

  20. Plant-Derived Tick Repellents Activate the Honey Bee Ectoparasitic Mite TRPA1.

    PubMed

    Peng, Guangda; Kashio, Makiko; Morimoto, Tomomi; Li, Tianbang; Zhu, Jingting; Tominaga, Makoto; Kadowaki, Tatsuhiko

    2015-07-14

    We have identified and characterized the TRPA1 channel of Varroa destructor (VdTRPA1), a major ectoparasitic mite of honey bee. One of the two VdTRPA1 isoforms, VdTRPA1L, was activated by a variety of plant-derived compounds, including electrophilic compounds, suggesting that chemical activation profiles are mostly shared between arthropod TRPA1 channels. Nevertheless, carvacrol and α-terpineol activated VdTRPA1L but not a honey bee noxious-stimuli-sensitive TRPA, AmHsTRPA, and Drosophila melanogaster TRPA1. Activation of VdTRPA1L in D. melanogaster taste neurons by the above compounds was sufficient to modify the gustatory behaviors. Carvacrol and α-terpineol repelled V. destructor in a laboratory assay, and α-terpineol repressed V. destructor entry for reproduction into the brood cells in hives. Understanding the functions of parasite TRP channels not only gives clues about the evolving molecular and cellular mechanisms of parasitism but also helps in the development of control methods.

  1. Stabilization of thin liquid films by repulsive van der Waals force.

    PubMed

    Li, Er Qiang; Vakarelski, Ivan U; Chan, Derek Y C; Thoroddsen, Sigurdur T

    2014-05-13

    Using high-speed video recording of bubble rise experiments, we study the stability of thin liquid films trapped between a rising bubble and a surfactant-free liquid-liquid meniscus interface. Using different combinations of nonpolar oils and water that are all immiscible, we investigate the extent to which film stability can be predicted by attractive and repulsive van der Waals (vdW) interactions that are indicated by the relative magnitude of the refractive indices of the liquid combinations, for example, water (refractive index, n = 1.33), perfluorohexane (n = 1.23), and tetradecane (n = 1.43). We show that, when the film-forming phase was oil (perfluorohexane or tetradecane), the stability of the film could always be predicted from the sign of the vdW interaction, with a repulsive vdW force resulting in a stable film and an attractive vdW force resulting in film rupture. However, if aqueous electrolyte is the film-forming bulk phase between the rising air bubble and the upper oil phase, the film always ruptured, even when a repulsive vdW interaction was predicted. We interpret these results as supporting the hypothesis that a short-ranged hydrophobic attraction determines the stability of the thin water film formed between an air phase and a nonpolar oil phase. PMID:24761748

  2. Effect of gravity on virus and clay colloid cotransport through vertical water-saturated columns

    NASA Astrophysics Data System (ADS)

    Syngouna, Vasiliki I.; Chrysikopoulos, Constantinos V.

    2015-04-01

    The cotransport of clay colloids and viruses in vertically oriented laboratory columnspacked with glass beadswas investigated. Bacteriophages MS2 and ΦX174 were used as model viruses, and kaolinite (kGa-1b) and montmorillonite (STx-1b) as model clay colloids. A steady flow rate of Q=1.5 mL/min was applied in bothvertical upward (VU) and vertically downward (VD) flowdirections. For most of the cases examined in this study, estimated mass recovery values were higher for VD than VU flows, suggesting that the flow direction significantly influenced particle deposition.KGa-1b hindered the transport of ΦX174 under VD flow conditions,while STx-1b facilitated the transport of ΦX174 under both VU and VD flow conditions. Moreover, KGa-1b hindered,while STx-1b facilitated the transport of MS2 in all of thecases examined. Also, the experimental data were used for the estimation of virus surface-coverages, and virus surface concentrations for virus diffusion-limited adsorption, and virus adsorption by sedimentation. The sedimentation limited virus adsorption was higher for VD than VU flows, and the diffusion-limited adsorption was higher for MS2 than ΦX174.

  3. Benzene on Cu(111): II. Molecular assembly due to Lateral van der Waals and Surface-State-Mediated Indirect Interactions

    NASA Astrophysics Data System (ADS)

    Hyldgaard, Per; Berland, Kristian; Einstein, T. L.

    2010-03-01

    Experiments show that benzene condenses into two different structural phases: a compact and a sparse phase, both of approximately hexagonal symmetry. The vdW-DF calculations demonstrate that the denser benzene-overlayer phase, with lattice constant 6.74 ,s due to direct benzene-benzene vdW attraction. The structure of the second, sparser phase, with lattice spacing 10.24 ,s attributed to the indirect electronic interactions mediated by the well-known metallic surface state on Cu(111). To support this claim, we use a formal Harris-functional approach to evaluate nonperturbatively the asymptotic form of this indirect interaction. Our extended vdW-DF scheme---which combines calculations of molecular physisorption, of direct intermolecular vdW coupling, and of indirect electronic interactions between the molecular adsorbates---accounts well for the structural phases of benzene on Cu(111). Our preliminary vdW-DF study of acene and quinone interactions provides building blocks for modeling of anthraquinone assembly on Cu(111).footnotetextG. Pawin, , L. Bartels, Science 313 (2006) 961

  4. Periodic flow at airway bifurcations. III. Energy dissipation.

    PubMed

    Tsuda, A; Savilonis, B J; Kamm, R D; Fredberg, J J

    1990-08-01

    We measured the energy dissipation associated with large-amplitude periodic flow through airway bifurcation models. Each model consisted of a single asymmetric bifurcation with a different branching angle and area ratio, with each branch terminated into an identical elastic load. Sinusoidal volumetric oscillations were applied at the parent duct so that the upstream Reynolds number (Re) varied from 30 to 77,000 and the Womersley parameter (alpha) from 4 to 30. Pressures were measured continuously at the parent duct and at both terminals, and instantaneous branch flow rates were calculated. Time-averaged energy dissipation in the bifurcation was computed from an energy budget over a control volume integrated over a cycle and was expressed as a friction factor, F. We found that when tidal volume was small [ratio of tidal volume to resident (dead space) volume, VT/VD less than 1], F was independent of branching angle and fell with increasing alpha and VT/VD. When tidal volume was large (VT/VD greater than 1), F increased with increasing branching angle and varied less strongly with alpha and VT/VD. No simple benchmark flow represented the data well over the entire experimental range. This study demonstrates that only two nondimensional parameters, alpha and VT/VD, are necessary and are sufficient to describe time-averaged energy dissipation in a given bifurcation geometry during sinusoidal flow.

  5. Communication: Accurate higher-order van der Waals coefficients between molecules from a model dynamic multipole polarizability

    NASA Astrophysics Data System (ADS)

    Tao, Jianmin; Rappe, Andrew M.

    2016-01-01

    Due to the absence of the long-range van der Waals (vdW) interaction, conventional density functional theory (DFT) often fails in the description of molecular complexes and solids. In recent years, considerable progress has been made in the development of the vdW correction. However, the vdW correction based on the leading-order coefficient C6 alone can only achieve limited accuracy, while accurate modeling of higher-order coefficients remains a formidable task, due to the strong non-additivity effect. Here, we apply a model dynamic multipole polarizability within a modified single-frequency approximation to calculate C8 and C10 between small molecules. We find that the higher-order vdW coefficients from this model can achieve remarkable accuracy, with mean absolute relative deviations of 5% for C8 and 7% for C10. Inclusion of accurate higher-order contributions in the vdW correction will effectively enhance the predictive power of DFT in condensed matter physics and quantum chemistry.

  6. Modern theory of van der Waals interactions

    NASA Astrophysics Data System (ADS)

    Dobson, John

    2014-03-01

    van der Waals (vdW, dispersion) interactions are important in diverse areas such as colloid, surface and nano science, cohesion of molecular crystals, and biomolecular science. They also provide competition in experiments to discover the fifth fundamental force.While vdW interactions have been understood in principle for a century, their quantitative first-principles prediction and modelling down to chemical contact separations have proven stubbornly difficult because the quantal many-electron problem is involved. After some brief historical material, the current state of the art will be discussed with particular reference to several approaches: pairwise additive, perturbative quantum chemical, vdW-DF, Lifshitz-like scattering, RPA-like, Adiabatic Connection Fluctuation Dissipation / Time Dependent DFT based etc.. A potentially useful classification will be introduced to aid in understanding the physical causes of departures from pairwise additivity, that is from the usual sum of C6R-6 contributions. These departures result in non-standard power law decays of nanostructure vdW interactions as a function of separation D, as well as surprising dependences of the attraction on the number, N, of atoms within each vdW-interacting fragment. Some further recent results on non-additivity will also be presented. Work supported by an Australian Research Council Discovery Grant.

  7. Non-additivity of molecule-surface van der Waals potentials from force measurements

    NASA Astrophysics Data System (ADS)

    Tautz, Stefan

    2014-03-01

    Van der Waals (vdW) forces act ubiquitously in condensed matter. Their description as an inherently quantum mechanical phenomenon was developed for single atoms and homogeneous macroscopic bodies by London, Casimir, and Lifshitz. For intermediate-sized objects like organic molecules an atomistic description is required, but explicit first principles calculations are very difficult since correlations between many interacting electrons have to be considered. Hence, semi-empirical correction schemes are often used that simplify the vdW interaction to a sum over atom-pair potentials. A similar gap exists between successful measurements of vdW and Casimir forces for single atoms on the one hand and macroscopic bodies on the other, as comparable experiments for molecules are absent. I will present experiments in which long-range vdW potentials between a series of related molecules and a metal surface have been determined experimentally. The experiments rely on the extremely sensitive force detection of an atomic force microscope in combination with its molecular manipulation capabilities. The results allow us to confirm the asymptotic force law and to quantify the non-additive part of the vdW interaction which is particularly challenging for theory. In the present case, cooperative effects account for 10% of the total interaction. This effect is of general validity in molecules and thus relevant at the intersection of chemistry, physics, biology, and materials science.

  8. [Science and society. Guidelines for the Leopoldina Study Center].

    PubMed

    Hacker, Jörg

    2014-01-01

    In order to adequately perform its many diverse tasks as a scholars' society and as the German National Academy of Sciences, the Deutsche Akademie der Naturforscher Leopoldina needs to view itself in a historical context. This can only happen as part of a culture of remembrance which fosters the memory of the Leopoldina's past and subjects this to a critical analysis in the context of the history of science and academies. The newly founded Leopoldina Study Center for the History of Science and Science Academies is to be a forum that pursues established forms of historical research at the Leopoldina, organizes new scientific projects, and presents its findings to the public. The aim is to involve as many Leopoldina members as possible from all of its disciplines, as well as to collaborate with national and international partners.

  9. On the theory of the Balmer series⋆. Presented at the meeting on 6 December 1915

    NASA Astrophysics Data System (ADS)

    Sommerfeld, A.

    2014-04-01

    The German original was published as "Zur Theorie der Balmerschen Serie" in Sitzungsberichte der mathematisch-physikalischen Klasse der K. B. Akademie der Wissenschaften zu München, 1915, S. 425-458; it is available as electronic supplementary material at http://dx.doi.org/10.1140/epjh/e2013-40053-8 or in the printed collection, Eckert, M. and Sommerfeld, A. (2013). Die Bohr-Sommerfeldsche Atomtheorie: Sommerfelds Erweiterung des Bohrschen Atommodells 1915/16. Klassische Texte der Wissenschaft. Springer, Berlin, Heidelberg.The translation here is by Patrick D.F. Ion, 1456 Kensington Drive, Ann Arbor, MI 48104-6214; e-mail: ion@ams.org. The numbers in the margins indicate the starts of original pages translated. The footnote numbering has been changed from the original to match the English text.

  10. The fine structure of Hydrogen and Hydrogen-like lines⋆. Presented at the meeting on 8 January 1916

    NASA Astrophysics Data System (ADS)

    Sommerfeld, A.

    2014-04-01

    The German original was published as "Die Feinstruktur der Wasserstoff- und der Wasserstoff-ähnlichen Linien" in Sitzungsberichte der mathematisch-physikalischen Klasse der K. B. Akademie der Wissenschaften zu München, 1915, S. 459-500; it is available as electronic supplementary material at http://dx.doi.org/10.1140/epjh/e2013-40054-0 or in the printed collection, Eckert, M. and Sommerfeld, A. (2013). Die Bohr-Sommerfeldsche Atomtheorie: Sommerfelds Erweiterung des Bohrschen Atommodells 1915/16. Klassische Texte der Wissenschaft. Springer, Berlin, Heidelberg.The translation here is by Patrick D. F. Ion, 1456 Kensington Drive, Ann Arbor, MI 48104-6214; e-mail: ion@ams.org. The numbers in the margins indicate the starts of original pages translated. The footnote numbering has been changed from the original to match the English text.

  11. Content and quality of protein in proso millet (Panicum miliaceum L.) varieties.

    PubMed

    Kalinova, Jana; Moudry, Jan

    2006-03-01

    Proso millet belongs to the oldest cereals that human is using. Eight varieties of proso millet were cultivated in Ceske Budejovice from 1998 to 2000 and Cerveny Dvur from 1999 to 2000. The crude protein content was determined according to Kjehladl method and amino acid content was determined chromatographically after acid and oxidative acid hydrolysis. Although the protein content of proso (11.6% of dry matter) was similar to wheat, the grain of proso was significant richer in essential amino acids (leucine, isoleucine, methionine) then wheat. Hence, the protein quality of proso (Essential Amino Acid Index) was higher (51%) compared to wheat. The proso grain contained about 3.3 g kg(-1) of the limiting amino acid-lysine. Significant differences in protein and its quality were found among the evaluated proso varieties. The varieties Toldanskoe and Lipetskoe were the most different from the others in protein and amino acid content and Amino Acid Score of individual acids. They had the lowest content and quality of protein. The seed coat of these varieties was red. The amino acid and protein content was significantly influenced by weather during the year. Dry conditions caused an increase of protein but its quality was decreased.

  12. A standardised terminology of the embryonic envelopes and associated developmental stages of tapeworms (Platyhelminthes: Cestoda).

    PubMed

    Conn, David Bruce; Swiderski, Zdzisław

    2008-03-01

    Over the past 40 years, much has been published on the ultrastructure and cellular development of embryonic structures in a wide range of cestodes. However, the literature contains many discrepancies in both terminology and interpretations because of the facts that these organisms are phylogenetically diverse within their respective orders and families, the habitats that affect embryonic envelope structure are diverse, and the work has been done in various laboratories around the world. This review and synthesis was initiated by a working group of biologists from around the world convened at the Fifth International Workshop on Cestode Systematics and Phylogeny in Ceské Budejovice, at the Institute of Parasitology of the Biology Centre, Academy of Sciences of the Czech Republic. It brings together the data from published work and establishes a uniform terminology and interpretation based on the data as they are presented. A consensus was reached for standardised definitions of the oncosphere, hexacanth, coracidium, embryonic envelopes, outer envelope, inner envelope, embryophore, vitelline capsule, shell, and outer coat. All of these are defined as components of the embryo or its vitellocyte-derived or uterine-derived coatings.

  13. [Jirí Josef Camel, pharmacist and botanist].

    PubMed

    Entner, J

    1990-02-01

    Jirí Josef Camel (1661-1706), a pharmacist and botanist, was born in Brno, educated at a grammar school and then joined the Jesuit Order as a laic brother. He worked in the college pharmacies in Brno, Jindrichův Hradec and Ceský Krumlov. In 1687 he left for a religious mission to the Philippine Islands, where he worked for 17 years in a hospital as a pharmacist. He died in Manila in 1706. He wrote 19 treatises, in which he acquainted European medicine and pharmacy with the flora and fauna of the Philippines. Camel sent his papers to London to J. Ray, the then most distinguished authority in botany. Ray published them in the 3rd volume of Historia Plantarum in 1704. The most valuable part of his work are drawings of plants, published by Petiver in the journal Gazophylacei naturae et artis (1702-1709). More than 400 of them have survived till nowadays in the collection of the British Museum. Further 260 drawings were acquired in the course of years by the University Library in Louvain.

  14. East-west asymmetry in type-2 echoes and enhanced electron drift in the equatorial electrojet

    NASA Astrophysics Data System (ADS)

    Tsunoda, Roland T.; Ecklund, Warner L.

    2002-04-01

    Simultaneous measurements of type-2 echoes in the equatorial electrojet (EEJ) and the 150 km echoes were made with a tri-beam radar on Pohnpei (Federated States of Micronesia). Using the mean Doppler velocity (<VD>) to estimate the line-of-sight component of electron drift velocity ([(V_e)]), we show that its vertical component (Vez) increases with altitude and exceeds Vez measured at 150 km, between 96 and 103 km. At 103 km, the ratio of vertical <VD> to Vez at 150 km was five. This enhancement explains the hitherto puzzling east-west asymmetry in <VD> of type-2 echoes. More importantly, we show how the enhanced Vez appears to be associated with the discrepancy in the altitude of peak current density of the EEJ, between measurement and model. We discuss roles played by kilometer-scale irregularities and close by describing apparent effects by atmospheric gravity waves.

  15. Nanomechanical probing of the layer/substrate interface of an exfoliated InSe sheet on sapphire.

    PubMed

    Beardsley, Ryan; Akimov, Andrey V; Greener, Jake D G; Mudd, Garry W; Sandeep, Sathyan; Kudrynskyi, Zakhar R; Kovalyuk, Zakhar D; Patanè, Amalia; Kent, Anthony J

    2016-01-01

    Van der Waals (vdW) layered crystals and heterostructures have attracted substantial interest for potential applications in a wide range of emerging technologies. An important, but often overlooked, consideration in the development of implementable devices is phonon transport through the structure interfaces. Here we report on the interface properties of exfoliated InSe on a sapphire substrate. We use a picosecond acoustic technique to probe the phonon resonances in the InSe vdW layered crystal. Analysis of the nanomechanics indicates that the InSe is mechanically decoupled from the substrate and thus presents an elastically imperfect interface. A high degree of phonon isolation at the interface points toward applications in thermoelectric devices, or the inclusion of an acoustic transition layer in device design. These findings demonstrate basic properties of layered structures and so illustrate the usefulness of nanomechanical probing in nanolayer/nanolayer or nanolayer/substrate interface tuning in vdW heterostructures.

  16. Nanomechanical probing of the layer/substrate interface of an exfoliated InSe sheet on sapphire

    NASA Astrophysics Data System (ADS)

    Beardsley, Ryan; Akimov, Andrey V.; Greener, Jake D. G.; Mudd, Garry W.; Sandeep, Sathyan; Kudrynskyi, Zakhar R.; Kovalyuk, Zakhar D.; Patanè, Amalia; Kent, Anthony J.

    2016-06-01

    Van der Waals (vdW) layered crystals and heterostructures have attracted substantial interest for potential applications in a wide range of emerging technologies. An important, but often overlooked, consideration in the development of implementable devices is phonon transport through the structure interfaces. Here we report on the interface properties of exfoliated InSe on a sapphire substrate. We use a picosecond acoustic technique to probe the phonon resonances in the InSe vdW layered crystal. Analysis of the nanomechanics indicates that the InSe is mechanically decoupled from the substrate and thus presents an elastically imperfect interface. A high degree of phonon isolation at the interface points toward applications in thermoelectric devices, or the inclusion of an acoustic transition layer in device design. These findings demonstrate basic properties of layered structures and so illustrate the usefulness of nanomechanical probing in nanolayer/nanolayer or nanolayer/substrate interface tuning in vdW heterostructures.

  17. Accurate and efficient method for many-body van der Waals interactions.

    PubMed

    Tkatchenko, Alexandre; DiStasio, Robert A; Car, Roberto; Scheffler, Matthias

    2012-06-01

    An efficient method is developed for the microscopic description of the frequency-dependent polarizability of finite-gap molecules and solids. This is achieved by combining the Tkatchenko-Scheffler van der Waals (vdW) method [Phys. Rev. Lett. 102, 073005 (2009)] with the self-consistent screening equation of classical electrodynamics. This leads to a seamless description of polarization and depolarization for the polarizability tensor of molecules and solids. The screened long-range many-body vdW energy is obtained from the solution of the Schrödinger equation for a system of coupled oscillators. We show that the screening and the many-body vdW energy play a significant role even for rather small molecules, becoming crucial for an accurate treatment of conformational energies for biomolecules and binding of molecular crystals. The computational cost of the developed theory is negligible compared to the underlying electronic structure calculation.

  18. On the pseudopotential approximation in the van der Waals density functional calculations

    NASA Astrophysics Data System (ADS)

    Hamada, Ikutaro; Callsen, Martin

    The van der Waals density functional (vdW-DF) is a density functional that is able to describe van der Waals and covalent interactions in a seamless fashion, and has been applied to a variety of systems. In practical calculations, the pseudopotential (PP) approximation has been employed, for which the PPs should be generated consistently for the chosen exchange correlation XC functional. However, usually PPs generated with a generalized gradient approximation (GGA) XC functional are used and the effect of the approximation to the XC functional applied in the PP generation is scarcely discussed. In this work, we discuss the appropriate XC functionals in the PP generation for the vdW-DF calculations. Furthermore, we compare the vdW-DF results for several systems using the PP's generated with appropriate XC and those with GGA XC.

  19. Endogenous estimation of safety coefficient for optimal design of biochemical reactors at industrial level

    NASA Astrophysics Data System (ADS)

    Siontorou, Christina G.; Karydi, Angeliki

    2012-12-01

    This work deals with the endogenous estimation of the Safety Coefficient Ge = Vd/Vm, where Vd is the design volume and Vm is the mean volume of liquid of a biochemical reactor operating at industrial level. The Vd-value is estimated through Monte Carlo simulation while Vm-value is obtained by means of material balances and biochemical kinetics. A case example on waste water biological treatment is presented, referring to a well-mixed bioreactor followed by a clarifier. The Ge-values finally estimated are in the lower part of the (exogenously determined) region as suggested in the relevant technical literature, implying a significant saving of investment capital, which forms the principle component of fixed cost. Similar applications are also mentioned in brief.

  20. Nanomechanical probing of the layer/substrate interface of an exfoliated InSe sheet on sapphire.

    PubMed

    Beardsley, Ryan; Akimov, Andrey V; Greener, Jake D G; Mudd, Garry W; Sandeep, Sathyan; Kudrynskyi, Zakhar R; Kovalyuk, Zakhar D; Patanè, Amalia; Kent, Anthony J

    2016-01-01

    Van der Waals (vdW) layered crystals and heterostructures have attracted substantial interest for potential applications in a wide range of emerging technologies. An important, but often overlooked, consideration in the development of implementable devices is phonon transport through the structure interfaces. Here we report on the interface properties of exfoliated InSe on a sapphire substrate. We use a picosecond acoustic technique to probe the phonon resonances in the InSe vdW layered crystal. Analysis of the nanomechanics indicates that the InSe is mechanically decoupled from the substrate and thus presents an elastically imperfect interface. A high degree of phonon isolation at the interface points toward applications in thermoelectric devices, or the inclusion of an acoustic transition layer in device design. These findings demonstrate basic properties of layered structures and so illustrate the usefulness of nanomechanical probing in nanolayer/nanolayer or nanolayer/substrate interface tuning in vdW heterostructures. PMID:27256805

  1. Improving the Description of Nonmagnetic and Magnetic Molecular Crystals via the van der Waals Density Functional

    NASA Astrophysics Data System (ADS)

    Obata, Masao; Nakamura, Makoto; Hamada, Ikutaro; Oda, Tatsuki

    2015-02-01

    We have derived and implemented a stress tensor formulation for the van der Waals density functional (vdW-DF) with spin-polarization-dependent gradient correction (GC) recently proposed by the authors [J. Phys. Soc. Jpn. 82, 093701 (2013)] and applied it to nonmagnetic and magnetic molecular crystals under ambient condition. We found that the cell parameters of the molecular crystals obtained with vdW-DF show an overall improvement compared with those obtained using local density and generalized gradient approximations. In particular, the original vdW-DF with GC gives the equilibrium structural parameters of solid oxygen in the α-phase, which are in good agreement with the experiment.

  2. Adsorption and electronic properties of Fullerene/Zn-Phthalocyanine (C60/ZnPc) interface with face-on orientation: A van der Waals corrected Density Functional Theory investigation

    NASA Astrophysics Data System (ADS)

    Javaid, Saqib; Akhtar, M. Javed

    2016-04-01

    We have investigated the C60/ZnPc interfacial properties in face-on orientation by using van der Waals (vdW)-corrected density functional theory (DFT) techniques. These findings show that different vdW approaches qualitatively provide a similar description of ZnPc adsorption on C60. Adsorption of ZnPc on C60 leads to the formation of an interface dipole. The magnitudes of charge transfer and interface dipole are found to be sensitive to the vdW method employed. These results suggest that C60/ZnPc interface dipole originates mainly as a result of charge transfer instead of adsorption induced charge re-arrangement.

  3. Complete genome sequence of a novel dsRNA mycovirus isolated from the phytopathogenic fungus Verticillium dahliae Kleb.

    PubMed

    Feng, Zili; Zhu, Heqin; Li, Zhifang; Shi, Yongqiang; Zhao, Lihong; Liu, Lijiang; Jiang, Daohong

    2013-12-01

    A novel double-stranded RNA (dsRNA) mycovirus, designated Verticillium dahliae partitivirus 1 (VdPV1), was isolated from a strain of the fungus Verticillium dahliae. The VdPV1 genome has two dsRNA genome segments. The larger segment (1768 bp) has a single open reading frame (ORF) with a conserved RNA-dependent RNA polymerase (RdRP) domain. The smaller segment (1587 bp) contains a single ORF encoding a putative coat protein. Analysis of its genomic structure indicated that VdPV1 is a new member of the genus Partitivirus. We report the full-length sequence of this partitivirus that infects Verticillium dahliae, the causal agent of verticillium wilt of cotton.

  4. Self-consistent van der Waals density functional study of benzene adsorption on Si(100)

    NASA Astrophysics Data System (ADS)

    Hamamoto, Yuji; Hamada, Ikutaro; Inagaki, Kouji; Morikawa, Yoshitada

    2016-06-01

    The adsorption of benzene on the Si(100) surface is studied theoretically using the self-consistent van der Waals density functional (vdW-DF) method. The adsorption energies of two competing adsorption structures, butterfly (BF) and tight-bridge (TB) structures, are calculated with several vdW-DFs at saturation coverage. Our results show that recently proposed vdW-DFs with high accuracy all prefer TB to BF, in accord with more accurate calculations based on exact exchange and correlation within the random-phase approximation. Detailed analyses reveal the important roles played by the molecule-surface interaction and molecular deformation upon adsorption, and we suggest that their precise description is a prerequisite for accurate prediction of the most stable adsorption structure of organic molecules on semiconductor surfaces.

  5. Stability of the kinetic Alfven wave in a current-less plasma

    NASA Astrophysics Data System (ADS)

    Sreekala, G.; Sebastian, Sijo; Michael, Manesh; Abraham, Noble P.; Renuka, G.; Venugopal, Chandu

    2015-06-01

    The two potential theory of Hasegawa has been used to derive the dispersion relation for the kinetic Alfven wave (KAW) in a plasma composed of hydrogen, oxygen and electrons. All three components have been modeled by ring distributions (obtained by subtracting two Maxwellian distributions with different temperatures) with the hydrogen and electrons drifting, respectively, with velocities VdH and Vde. For the most general case, the dispersion relation is a polynomial equation of order five; it reduces to a relation which supports only one mode when VdH = 0. For typical parameters at comet Halley, we find that both VdH and Vde can drive the wave unstable; the KAW is thus driven unstable in a current-less plasma. Such an instability was found for the ion acoustic wave by Vranjes et al. (2009).

  6. Spectroscopic measurement of the titanium-helium van der Waals molecule: TiHe

    NASA Astrophysics Data System (ADS)

    Quiros, Nancy; Tariq, Naima; Weinstein, Jonathan

    2016-05-01

    Atoms that are weakly bound by the van der Waals (vdW) interaction are known as van der Waals molecules. The existence and formation of vdW molecules is favorable at low temperatures due to their weak binding energy. We have used laser ablation and helium buffer gas cooling to create the exotic vdW diatomic molecule made of titanium (Ti) and helium (He). TiHe molecules were detected through laser-induced-fluorescence spectroscopy closely blue-detuned from the a3F2 --> y3F3 atomic Ti transition at 25227 cm-1. Measurements of the binding energy of TiHe were obtained by studying its equilibrium thermodynamic properties. It is believed the molecules are formed from the constituent cold atoms through three-body recombination. Progress towards measuring the three-body recombination rate coefficient will be discussed. This material is based upon work supported by National Science Foundation under Grant No. PHY 1265905.

  7. Nanomechanical probing of the layer/substrate interface of an exfoliated InSe sheet on sapphire

    PubMed Central

    Beardsley, Ryan; Akimov, Andrey V.; Greener, Jake D. G.; Mudd, Garry W.; Sandeep, Sathyan; Kudrynskyi, Zakhar R.; Kovalyuk, Zakhar D.; Patanè, Amalia; Kent, Anthony J.

    2016-01-01

    Van der Waals (vdW) layered crystals and heterostructures have attracted substantial interest for potential applications in a wide range of emerging technologies. An important, but often overlooked, consideration in the development of implementable devices is phonon transport through the structure interfaces. Here we report on the interface properties of exfoliated InSe on a sapphire substrate. We use a picosecond acoustic technique to probe the phonon resonances in the InSe vdW layered crystal. Analysis of the nanomechanics indicates that the InSe is mechanically decoupled from the substrate and thus presents an elastically imperfect interface. A high degree of phonon isolation at the interface points toward applications in thermoelectric devices, or the inclusion of an acoustic transition layer in device design. These findings demonstrate basic properties of layered structures and so illustrate the usefulness of nanomechanical probing in nanolayer/nanolayer or nanolayer/substrate interface tuning in vdW heterostructures. PMID:27256805

  8. Grundsätze über die Anlagen neuer Sternwarten mit Beziehung auf die Sternwarte der Universität Göttingen. Von Georg Heinrich Borheck

    NASA Astrophysics Data System (ADS)

    Beuermann, Klaus; Borheck, Georg Heinrich

    Die Göttinger Sternwarte, Wirkungsstätte des berühmten Gelehrten Carl Friedrich Gauß, ist ein bedeutendes Baudenkmal. Im Jahre 2005 wird sie gemeinsam von der Georg-August-Universität und der Akademie der Wissenschaften zu Göttingen renoviert, um dann als repräsentatives Gebäude der Universität und Arbeitsstätte der Akademie zu dienen. Die Nutzung der historischen Räume für Ausstellungen macht diesen imposanten Bau erstmals der Öffentlichkeit zugänglich. Die Sternwarte war bei ihrer Errichtung vor 200 Jahren ein nach seinerzeit neuesten wissenschaftlichen Erkenntnissen konzipierter Bau, der die Universität Göttingen in eine der vordersten Stellen Europa rückte. Auch aufgrund ihrer Architektur ist sie ein großer Wurf des Göttinger Universitätsbaumeisters Georg Heinrich Borheck. Durch die Kriegswirren der Napoleonischen Zeit zerschlug sich Borhecks Versuch einer Publikation seiner Beschreibung des Baus der Göttinger Sternwarte 1805. Doch seine Schrift ist auch heute noch aktuell und wird mit diesem Band erstmals einer breiten Öffentlichkeit zugängig gemacht. Er zeigt die Grundsätze, nach denen damals öffentliche Bauten konzipiert wurden, erläutert die Bedeutung des Baus aus kunst- und wissenschaftshistorischer Sicht und informiert über die Pläne zur Restaurierung der Sternwarte in einem separaten Beitrag und im Geleitwort des Präsidenten der Georg-August Universität Prof. Dr. Dr. h. c. Kurt von Figura.

  9. On the differential properties of internal magnetic field models at the Earth's surface and at satellite altitudes

    NASA Astrophysics Data System (ADS)

    Webers, Wigor A.

    2007-03-01

    The inverse theory of potential fields shows that the correspondence between the internal magnetic field of the Earth and its field sources is unique when the potential field is known in all points of the three-dimensional space including all points of the source region (cp., e.g. Diesselhorst, H., 1939. Magnetische Felder und Kräfte. Johann Ambrosius Barth Verlag, Leipzig). Thus, to determine the sources of the field it is not sufficient to know the potential field in the space external to the sources. Moreover, field models derived from finite sets of potential field observations emphasize different source properties because of measurement errors. In this study, I argue that improved internal field models can be developed from multi-altitude magnetic observations by imposing more effective constraints on the poorly conditioned downward continuation problem. In particular, the convergence behaviour of spherical harmonic field models can be used to improve the downward continuation of the higher truncation index terms. A high quality approximation of the field continuation is essential when the field models are interpreted for relatively small field contributions such as from the lithospheric sources. The relations between the potential field and its sources including the problems of potential field continuations - upward and downward - are governed by the theory of ill-posed inverse problems (cp., e.g. Anger, G., 1990. Inverse Problems in Differential Equations. Akademie/Plenum Press, Berlin/London; Anger, G., Gorenflo, R., Jochmann, H., Moritz, H., Webers, W. (Eds.), 1993. Inverse Problems: Principles and Applications in Geophysics, Technology, and Medicine. Akademie, Berlin; Huestis, S.P., Parker, R.L., 1979. Upward and downward continuations as inverse problems. Geophys. J. R. Astr. Soc. 57, 171-188; Rösler, R., 1981. Über die Fehlerfortpflanzung bei Potentialfeldtransformationen. Gerlands Beitr. Gephys. 90, 47-57).

  10. High speed Radix-4 soft-decision Viterbi decoder for MB-OFDM UWB system

    NASA Astrophysics Data System (ADS)

    Liang, Guixuan; Portilla, Jorge; Riesgo, Teresa

    2013-05-01

    In this paper, a 64 state soft decision Viterbi Decoder (VD) system by using a high speed radix-4 Add Compare Select (ACS) architecture is presented. The proposed VD system can support different data rate (from 53.5 Mbps to 480 Mbps) for Multiband Orthogonal Frequency-division Multiplexing (MB-OFDM) Ultra-Wideband (UWB) system when implemented onto the FPGA board. The proposed VD employs efficient two steps Radix 4 architecture, which is responsible of calculating two steps of 64 state Radix 4 Branch Metrics (BM) within one clock cycle. The branch metrics are calculated using a uniform distance measurement algorithm, which equals to the symbol itself when compared to logic-0 and equal to its one's complement when compared to logic-1. By employing the modified Modulo Normalization algorithm, it is possible to use only a 10- bit memory block to restore each of the 64 state metrics, with the advantage of avoiding errors caused by overflow during the updating process for state metrics, and simplifying the comparator circuit of the ACS unit. The Two Pointer Even Algorithm, which is considered to be very simple and more hardware-efficient than the register exchange algorithm, is used for tracing back the survivor sequence and output the decoded data stream. 3-bit soft decision input sequences are used for gathering the experimental results. The sampling frequency of the MBOFDM UWB system is 528 MHz, by using the proposed two steps Radix 4 VD architecture we can process 4 input signals in parallel within one clock cycle, therefore only 132 MHz operating frequency is needed for the proposed VD system. This will dramatically reduce the dynamic power consumption for hardware implementation. Final results of the implementation show that the proposed VD architecture can support a maximum working frequency of 152.5 MHz on Xilinx XUPV5-LX110T Evaluation Platform.

  11. Low-sodium Dietary Approaches to Stop Hypertension-type diet including lean red meat lowers blood pressure in postmenopausal women.

    PubMed

    Nowson, Caryl A; Wattanapenpaiboon, Naiyana; Pachett, Annabelle

    2009-01-01

    Low-sodium Dietary Approaches to Stop Hypertension (DASH) diets are base producing but restrict red meat without clear justification. We hypothesized that a vitality diet (VD), a low-sodium DASH-type diet with a low dietary acid load containing 6 servings of 100 g cooked lean red meat per week, would be more effective in reducing blood pressure (BP) compared with a higher acid load reference healthy diet (RHD) based on general dietary guidelines to reduce fat intake and increase intake of breads and cereals. A randomized, parallel dietary intervention study was conducted to compare the BP-lowering effect of these 2 diets in postmenopausal women with high/normal BP. Women were randomly assigned to follow either VD or RHD for 14 weeks. Home BP was measured daily with an automated BP monitor under standard conditions. Of 111 women commencing the study, 95 completed (46 VD, 49 RHD). Systolic BP (SBP) throughout the intervention was lower in the VD group compared to the RHD group (repeated-measures analysis of variance time by diet, P = .04), such that at the end of the study, the VD had a fall of SBP by 5.6 +/- 1.3 mm Hg (mean +/- SEM) compared with a fall of 2.7 +/- 1.0 mm Hg in the RHD (group difference, P = .08). When only those taking antihypertensive medications were assessed, the VD (n = 17) had a significant fall of 6.5 +/- 2.5 mm Hg SBP (P = .02) and 4.6 +/- 1.4 mm Hg diastolic BP (P = .005) after 14 weeks, and their BP was lower than that of the RHD group (n = 18) throughout the study (P < .05). We concluded that a low-sodium DASH diet with a low dietary acid load, which also included lean red meat on most days of the week, was effective in reducing BP in older women, particularly in those taking antihypertensive medications.

  12. Association of Retinoid X Receptor Alpha Gene Polymorphism with Clinical Course of Chronic Glomerulonephritis

    PubMed Central

    Grzegorzewska, Alicja E.; Ostromecki, Grzegorz; Zielińska, Paulina; Mostowska, Adrianna; Niemir, Zofia; Polcyn-Adamczak, Magdalena; Pawlik, Magdalena; Sowińska, Anna; Jagodziński, Paweł P.

    2015-01-01

    Background Vitamin D (VD), VD binding protein, VD receptor (VDR), and retinoids are involved in pathogenesis of chronic glomerulonephritis (ChGN). We aimed to compare distribution of VD pathway gene polymorphisms in ChGN patients showing glomerular filtration rate (GFR) category 1–3, GFR category 5D, and healthy controls in order to elucidate the role of VD-related polymorphisms in the course of ChGN. Material/Methods GFR category 1–3 ChGN patients (n=195), GFR category 5D ChGN patients (n=178), and controls (n=751) underwent testing for polymorphisms of genes encoding VD binding protein (GC, rs2298849, rs7041, rs1155563), VDR (VDR, rs2228570, rs1544410), and retinoid X receptor alpha (RXRA, rs10776909, rs10881578, rs749759). Results Among GFR 1–3 subjects possessing TT genotype of RXRA rs10776909, 75% of patients had nephrotic syndrome, and 37.5% had glomerular hyperfiltration defined as GFR >140 ml/min/1.73 m2, and, consequently, serum creatinine was lower in these patients compared to the remaining subjects (0.67±0.26 vs. 0.94±0.34, P=0.014). In GFR category 5D ChGN patients, frequencies of RXRA rs10776909 allele T (25% vs. 19%) and CT+TT (46% vs. 34%) were higher compared to frequencies of respective variants in controls (Ptrend=0.004, Pgenotype=0.008). Conclusions RXRA rs10776909 allele T is specifically involved in the pathogenesis of ChGN. This risk allele may be also associated with worse clinical course of ChGN. PMID:26610845

  13. Nesfatin-1 and Vitamin D levels may be associated with systolic and diastolic blood pressure values and hearth rate in polycystic ovary syndrome.

    PubMed

    Sahin, Figen Kir; Sahin, Serap Baydur; Ural, Ulku Mete; Cure, Medine Cumhur; Senturk, Senol; Tekin, Yesim Bayoglu; Balik, Gulsah; Cure, Erkan; Yuce, Suleyman; Kirbas, Aynur

    2015-01-01

    Obesity, insulin resistance (IR), inflammation, and hyperandrogenism may lead to polycystic ovary syndrome (PCOS) and hypertension. Nesfatin-1 (N1) may be related to IR, obesity, and hypertension. Furthermore, a vitamin D (VD) deficiency is associated with hypertension and PCOS. We aimed to investigate N1 and VD levels in PCOS that have an effect on systolic and diastolic blood pressure (BP) and heart rate (HR).This study included 54 patients with PCOS and 48 age-body mass index (BMI)-matched healthy controls. PCOS was diagnosed according to clinical practice guidelines. Ferriman-Gallwey scores (FGS) were calculated, while N1, VD, and other hormonal and biochemical parameters were measured for all subjects. Systolic and diastolic BP was measured as well. HR was calculated using an electrocardiogram.The levels of N1 (p < 0.001), high-sensitivity C-reactive protein (hs-CRP) (p = 0.036), homeostasis model assessment as an index of insulin resistance (HOMA-IR) (p < 0.001), systolic (p < 0.001) and diastolic (p < 0.001) BP and HR (p < 0.001) in the PCOS group were significantly higher than in the control group. However, the VD levels of the PCOS group were lower than the control group (p = 0.004). N1 had a strong positive correlation with BMI, HOMA-IR, hs-CRP, luteinizing hormone, systolic and diastolic BP, and HR. VD levels were negatively correlated with HOMA-IR and luteinizing hormone.Elevated N1 and decreased VD levels may be related to the presence of high-normal BP or hypertension in PCOS subjects.  N1 level may be associated with an increased BP due to its relation to inflammation and IR.

  14. Impact of caesarean section on mode of delivery, pregnancy-induced and pregnancy-associated disorders, and complications in the subsequent pregnancy in Germany

    PubMed Central

    Jacob, Louis; Taskan, Sevil; Macharey, George; Sechet, Ingeborg; Ziller, Volker; Kostev, Karel

    2016-01-01

    Objectives: To analyze the impact of caesarean section (CS) on mode of delivery, pregnancy-induced and pregnancy-associated disorders, as well as complications in the subsequent pregnancy within German gynecological practices. Methods: 1,801 women with CS and 1,801 matched women with vaginal delivery (VD) from the IMS Disease Analyzer database were included. The impact of previous CS on the mode of delivery and pregnancy-associated disorders as well as complications prior to or during birth in the subsequent pregnancy were analyzed. Cox regressions were used to determine the influence of CS with regard to these outcomes. Results: Medical abortion and single spontaneous delivery were significantly less frequent in women with a history of CS compared to VD (OR equal to 0.52 and 0.04 respectively), whereas CS after CS was the significantly more common mode of delivery (79.0% versus 9.3%, OR=36.47). Gestational hypertension without significant proteinuria, gestational hypertension with significant proteinuria, and polyhydramnios were more frequent in women with CS than in women with VD (OR equal to 6.80, 1.71, and 2.29). Hemorrhage and maternal care for known or suspected disproportion were more common in the CS group than in the VD group (OR equal to 1.34 and 3.75). Prolonged pregnancy, preterm labor, abnormalities arising from forces of labor, and perineal laceration during delivery were significantly less frequent in women with CS than in women with VD (OR between 0.32 and 0.75), whereas long labor was more common (OR=2.09). Conclusion: Women with CS were more likely to undergo further CS and to develop major pregnancy-associated diseases in the following pregnancy compared to women with VD. PMID:27346991

  15. Voiding dysfunction in women: How to manage it correctly

    PubMed Central

    Abdel Raheem, A.; Madersbacher, Helmut

    2013-01-01

    Introduction Of women aged >40 years, 6% have voiding dysfunction (VD), but the definition for VD in women with respect to detrusor underactivity (DU) and bladder outlet obstruction (BOO) is not yet clear. In this review we address the current literature to define the diagnosis and treatment of VD more accurately. Methods We used the PubMed database (1975–2012) and searched for original English-language studies using the keywords ‘female voiding dysfunction’, ‘detrusor underactivity’, ‘acontractile detrusor’ and ‘bladder outlet obstruction and urinary retention in women’. We sought studies including the prevalence, aetiology, pathogenesis, diagnosis and treatment of female VD. Results In all, 20 original studies were identified using the selected search criteria, and another 45 were extracted from the reference lists of the original papers. All studies were selected according to their relevance to the current topic and the most pertinent reports were incorporated into this review. Conclusion Female VD might be related to DU or/and BOO. Voiding and storage symptoms can coexist, making the diagnosis challenging, with the need for a targeted clinical investigation, and further evaluation by imaging and urodynamics. To date there is no universally accepted precise diagnostic criterion to diagnose and quantify DU and BOO in women. For therapy, a complete cure might not be possible for patients with VD, therefore relieving the symptoms and minimising the long-term complications associated with it should be the goal. Treatment options are numerous and must be applied primarily according to the underlying pathophysiology, but also considering disease-specific considerations and the abilities and needs of the individual patient. The treatment options range from behavioural therapy, intermittent (self-)catheterisation, and electrical neuromodulation and neurostimulation, and up to urinary diversion in rare cases. PMID:26558099

  16. Two-dimensional GaSe/MoSe2 misfit bilayer heterojunctions by van der Waals epitaxy

    DOE PAGES

    Li, Xufan; Lin, Ming-Wei; Lin, Junhao; Huang, Bing; Puretzky, Alexander A.; Ma, Cheng; Wang, Kai; Zhou, Wu; Pantelides, Sokrates T.; Chi, Miaofang; et al

    2016-04-01

    Two-dimensional (2D) heterostructures hold the promise for future atomically-thin electronics and optoelectronics due to their diverse functionalities. While heterostructures consisting of different transition metal dichacolgenide monolayers with well-matched lattices and novel physical properties have been successfully fabricated via van der Waals (vdW) or edge epitaxy, constructing heterostructures from monolayers of layered semiconductors with large lattice misfits still remains challenging. Here, we report the growth of monolayer GaSe/MoSe2 heterostructures with large lattice misfit by two-step chemical vapor deposition (CVD). Both vertically stacked and lateral heterostructures are demonstrated. The vertically stacked GaSe/MoSe2 heterostructures exhibit vdW epitaxy with well-aligned lattice orientation between themore » two layers, forming an incommensurate vdW heterostructure. However, the lateral heterostructures exhibit no lateral epitaxial alignment at the interface between GaSe and MoSe2 crystalline domains. Instead of a direct lateral connection at the boundary region where the same lattice orientation is observed between GaSe and MoSe2 monolayer domains in lateral GaSe/MoSe2 heterostructures, GaSe monolayers are found to overgrow MoSe2 during CVD, forming a stripe of vertically stacked vdW heterostructure at the crystal interface. Such vertically-stacked vdW GaSe/MoSe2 heterostructures are shown to form p-n junctions with effective transport and separation of photo-generated charge carriers between layers, resulting in a gate-tunable photovoltaic response. In conclusion, these GaSe/MoSe2 vdW heterostructures should have applications as gate-tunable field-effect transistors, photodetectors, and solar cells.« less

  17. Structural and energetic requirements for a second binding site at the dimeric β-lactoglobulin interface.

    PubMed

    Bello, Martiniano

    2016-09-01

    Through experimental and theoretical approaches, it has been shown that bovine β-lactoglobulin (βlg) uses its hydrophobic cavity or calyx as the primary binding site for hydrophobic molecules, whereas the existence of a second ligand binding site at the dimeric interface has only been structurally identified for vitamin D3 (VD3). This binding exists even in the thermally denatured state, suggesting the prevalence of this secondary site. Although crystallographic experiments have suggested that VD3 can bind to both monomeric and dimeric states without significant structural differences, theoretical and experimental reports have proposed some structural requirements. Thus, in this study, based on known experimental data, the dynamic interaction of VD3 with the monomeric or dimeric forms of βlg was investigated through a protocol combining blind docking and 2 microsecond molecular dynamics simulations coupled with binding free energy and per-residue binding free energy decomposition analyses using the Molecular Mechanics Generalized Born Surface Area approach. Binding free energy calculations allowed us to estimate the energetic differences of coupling VD3 at the calyx and the dimeric interface for the monomeric or dimeric state, revealing that the dimeric structure is required to form a stable complex with VD3 at the dimeric interface. This also has an important impact on the dimerization process, whereas although the monomeric state also forms a stable complex with VD3 at the dimeric interface, the incorporation of the entropy component contributed to producing a marginally favorable binding free energy. Finally, the per-residue decomposition analysis provided energetic information about the most relevant residues in stabilizing the different systems.

  18. Supersaturating silicon with transition metals by ion implantation and pulsed laser melting

    NASA Astrophysics Data System (ADS)

    Recht, Daniel; Smith, Matthew J.; Charnvanichborikarn, Supakit; Sullivan, Joseph T.; Winkler, Mark T.; Mathews, Jay; Warrender, Jeffrey M.; Buonassisi, Tonio; Williams, James S.; Gradečak, Silvija; Aziz, Michael J.

    2013-09-01

    We investigate the possibility of creating an intermediate band semiconductor by supersaturating Si with a range of transition metals (Au, Co, Cr, Cu, Fe, Pd, Pt, W, and Zn) using ion implantation followed by pulsed laser melting (PLM). Structural characterization shows evidence of either surface segregation or cellular breakdown in all transition metals investigated, preventing the formation of high supersaturations. However, concentration-depth profiling reveals that regions of Si supersaturated with Au and Zn are formed below the regions of cellular breakdown. Fits to the concentration-depth profile are used to estimate the diffusive speeds, vD, of Au and Zn, and put lower bounds on vD of the other metals ranging from 102 to 104 m/s. Knowledge of vD is used to tailor the irradiation conditions and synthesize single-crystal Si supersaturated with 1019 Au/cm3 without cellular breakdown. Values of vD are compared to those for other elements in Si. Two independent thermophysical properties, the solute diffusivity at the melting temperature, Ds(Tm), and the equilibrium partition coefficient, ke, are shown to simultaneously affect vD. We demonstrate a correlation between vD and the ratio Ds(Tm)/ke0.67, which is exhibited for Group III, IV, and V solutes but not for the transition metals investigated. Nevertheless, comparison with experimental results suggests that Ds(Tm)/ke0.67 might serve as a metric for evaluating the potential to supersaturate Si with transition metals by PLM.

  19. Calcium effects and systemic exposure of vitamin D3 analogues after topical treatment of active vitamin D3-containing ointments in rats.

    PubMed

    Hosomi, Atsushi; Hirabe, Maho; Tokuda, Takuya; Nakamura, Hiroaki; Amano, Toru; Okamoto, Tadao

    2016-10-01

    Topical agents containing vitamin D3 (VD3) analogues such as calcipotriol, maxacalcitol and tacalcitol and the combination of calcipotriol/betamethasone dipropionate (betamethasone) are prescribed for patients with psoriasis. However, they are known to occasionally cause hypercalcemia, and the frequency of hypercalcemia is suggested to vary according to the VD3 analogue used. In this study, to address the reason for these differences, the calcemic effects of maxacalcitol-, calcipotriol- and calcipotriol/betamethasone-containing ointments in rats were evaluated. The serum calcium levels in rats treated with ointments containing maxacalcitol, but not calcipotriol or calcipotriol/betamethasone, were significantly elevated, which is consistent with clinical observations. The serum concentration of VD3 analogue in rats treated with ointments containing calcipotriol and calcipotriol/betamethasone was lower than that in rats treated with maxacalcitol-containing ointment. Thus, the calcemic effects appear to be associated with the systemic exposure of VD3 analogues in rats. To understand the mechanism underlying the different systemic exposures of VD3 analogues, skin permeation and metabolic stability of VD3 analogues were evaluated. The cumulative amount of calcipotriol permeated through rat skin was significantly lower than that of maxacalcitol. On the other hand, the metabolic clearance of calcipotriol in rat hepatocytes was higher than that of maxacalcitol. Similar results were obtained using human skin and human hepatocytes. The current study demonstrates that the lower calcemic effects of calcipotriol- and calcipotriol/betamethasone-containing ointments are caused by the low systemic exposure of calcipotriol according to low skin permeability and rapid hepatic elimination after topical application.

  20. Strong Room-temperature Negative Transconductance In An Axial Si/Ge Hetero-nanowire Tunneling Field-effect Transistor

    SciTech Connect

    Zhang, Peng; Le, Son T.; Hou, Xiaoxiao; Zaslavsky, A.; Perea, Daniel E.; Dayeh, Shadi A.; Picraux, Samuel T.

    2014-08-11

    We report on room-temperature negative transconductance (NTC) in axial Si/Ge hetero-nanowire tunneling field-effect transistors (TFETs). The NTC produces a current peak-to-valley ratio > 45, a high value for a Si-based device. We characterize the NTC characteristics over a range of gate VG and drain VD voltages, finding that NTC persists down to VD = –50 mV. The physical mechanism responsible for the NTC is the VG-induced depletion in the p-Ge section that eventually reduces the maximum electric field that triggers the tunneling ID, as confirmed via three-dimensional TCAD simulations.

  1. Constraints on the Interstellar Dust Flux Based on Stardust at Home Search Results

    NASA Technical Reports Server (NTRS)

    Zolensky, Michael E.; Westphal, J.; Allen, C.; Anderson, D.; Bajt, S.; Bechtel, H. A.; Borg, J.; Brenker, F.; Bridges, J.; Brownlee, D. E.; Burchell, M.

    2011-01-01

    Recent advances in active particle selection in the Heidelberg Van de r Graaf (VdG) dust accelerator have led to high-fidelity, low-backgro und calibrations of track sizes in aerogel as a function of particle size and velocity in the difficult regime above 10 km sec..1 and sub micron sizes. To the extent that the VdG shots are analogs for inters tellar dust (ISD) impacts, these new measurements enable us to place preliminary constraints on the ISD flux based on Stardust@home data.

  2. Nonadditivity of van der Waals forces on liquid surfaces

    NASA Astrophysics Data System (ADS)

    Venkataram, Prashanth S.; Whitton, Jeremy D.; Rodriguez, Alejandro W.

    2016-09-01

    We present an approach for modeling nanoscale wetting and dewetting of textured solid surfaces that exploits recently developed, sophisticated techniques for computing exact long-range dispersive van der Waals (vdW) or (more generally) Casimir forces in arbitrary geometries. We apply these techniques to solve the variational formulation of the Young-Laplace equation and predict the equilibrium shapes of liquid-vacuum interfaces near solid gratings. We show that commonly employed methods of computing vdW interactions based on additive Hamaker or Derjaguin approximations, which neglect important electromagnetic boundary effects, can result in large discrepancies in the shapes and behaviors of liquid surfaces compared to exact methods.

  3. "Cerenkov" dewetting at soft interfaces

    NASA Astrophysics Data System (ADS)

    Martin, A.; Buguin, A.; Brochard-Wyart, F.

    2002-02-01

    A non-wetting liquid is pressed between a rubber cap and a solid plate. When the plate slides at a velocity U larger than a critical value Uc, the contact is lubricated. However, if the sliding surface carries a nucleating centre (a local depression), a "dry wake" can be induced, with a well-defined wake angle α0, as in Cerenkov radiation. We interpret this by a competition between a dewetting velocity Vd and an invasion velocity U. The Mach relation sin α0 = Vd/U is obeyed. These effects are relevant to the hydroplaning of cars on wet roads.

  4. Continuum modeling of breathing-like modes of spherical carbon onions

    NASA Astrophysics Data System (ADS)

    Ghavanloo, Esmaeal; Ahmad Fazelzadeh, S.

    2015-08-01

    In this letter, an analytical formulation is developed for predicting the breathing-like modes of spherical carbon onions consisting of an arbitrary number of layers. The spherical layers of the carbon onions are concentrically nested, and are coupled through van der Waals (vdW) forces between two adjacent layers. Lennard-Jones potential and continuum models are utilized to estimate the vdW interaction coefficients and the breathing-like modes of the carbon onions. The formulation is justified by a good agreement between the results given by the present model and available experimental and numerical data. Finally, numerical results are obtained for various carbon onions.

  5. Characterization of the murine antibody response to peptides representing the variable domains of the major outer membrane protein of Chlamydia pneumoniae.

    PubMed Central

    Peterson, E M; Cheng, X; Qu, Z; de La Maza, L M

    1996-01-01

    In an attempt to gain more knowledge about the immunogenicity of the variable domains (VDs) of the major outer membrane protein (MOMP) of Chlamydia pneumoniae, peptides representing these areas were used to immunize BALB/c and C57BL/6 mice. Antisera to the peptides and to peptides conjugated to keyhole limpet hemocyanin (KLH) were characterized by their ability to recognize the immunizing peptide and elementary bodies (EBs) of C. pneumoniae by enzyme-linked immunosorbent assay (ELISA) and Western blot (immunoblot). In addition, antiserum was analyzed for its molecular specificity by a pepscan as well as its in vitro neutralizing ability. In general, results obtained with antisera to the peptides paralleled the results obtained with the antisera to the KLH-conjugated peptides except that the titers or strength of reaction in the assays was less. Antisera to the VDs in both strains of mice gave ELISA titers to the homologous VD peptide ranging from 1,000 to >64,000. The strength of reactivity with the reduced MOMP as judged by Western blot, in most cases, paralleled the ELISA titer to the peptide. However, only antisera raised in both strains of mice to the VD1 and VD4 peptides reacted strongly with the EBs, suggesting surface exposure of these VDs. In addition, antisera to VD3 from C57BL/6 mice gave strong reactivity to EBs. By pepscan analysis antisera from both strains of mice reacted with several VD1 and VD3 octameric peptides, with weaker reactivity being seen with the octameric peptides in the other two VDs. This was in contrast to antisera raised to EBs of C. pneumoniae TW-183, which identified two immunogenic regions, one in VD1 and the other mapped to VD4. While antisera raised to EBs strongly neutralized the infectivity of C. pneumoniae, none of the peptide antisera was able to neutralize. In addition, peptides to the VDs were not able to block the neutralizing ability of the antisera to EBs of C. pneumoniae. Therefore, these results suggest that the VDs of

  6. Expression of nephronectin is enhanced by 1α,25-dihydroxyvitamin D3.

    PubMed

    Hiranuma, Katsuhiro; Yamada, Atsushi; Kurosawa, Tamaki; Aizawa, Ryo; Suzuki, Dai; Saito, Yoshiro; Nagahama, Ryo; Ikehata, Mikiko; Tsukasaki, Masayuki; Morimura, Naoko; Chikazu, Daichi; Maki, Koutaro; Shirota, Tatsuo; Takami, Masamichi; Yamamoto, Matsuo; Iijima, Takehiko; Kamijo, Ryutaro

    2016-09-01

    The extracellular matrix protein nephronectin (Npnt), also called POEM, is considered to play critical roles as an adhesion molecule in development and functions of various tissues, such as the kidneys, liver, and bone. In the present study, we examined the molecular mechanism of Npnt gene expression and found that vitamin D3 (1α,25-dihydroxyvitamin D3,VD 3) strongly enhanced Npnt mRNA expression in MC3T3-E1 cells from a mouse osteoblastic cell line. The VD 3-induced increase in Npnt expression is both time- and dose-dependent and is mediated by the vitamin D receptor (VDR). PMID:27642554

  7. Influence of the van der Waals interaction in the dissociation dynamics of N{sub 2} on W(110) from first principles

    SciTech Connect

    Martin-Gondre, L.; Juaristi, J. I.; Blanco-Rey, M.; Díez Muiño, R.; Alducin, M.

    2015-02-21

    Using ab initio molecular dynamics (AIMD) calculations, we investigate the role of the van der Waals (vdW) interaction in the dissociative adsorption of N{sub 2} on W(110). Hitherto, existing classical dynamics calculations performed on six-dimensional potential energy surfaces based on density functional theory (DFT), and the semi-local PW91 and RPBE [Hammer et al. Phys. Rev. B 59, 7413 (1999)] exchange-correlation functionals were unable to fully describe the dependence of the initial sticking coefficient on the molecular beam incidence conditions as found in experiments. N{sub 2} dissociation on W(110) was shown to be very sensitive not only to short molecule-surface distances but also to large distances where the vdW interaction, not included in semilocal-DFT, should dominate. In this work, we perform a systematic study on the dissociative adsorption using a selection of existing non-local functionals that include the vdW interaction (vdW-functionals). Clearly, the inclusion of the non-local correlation term contributes in all cases to correct the unrealistic energy barriers that were identified in the RPBE at large molecule-surface distances. Among the tested vdW-functionals, the original vdW-DF by Dion et al. [Phys. Rev. Lett. 92, 246401 (2004)] and the ulterior vdW-DF2 give also an adequate description of the N{sub 2} adsorption energy and energy barrier at the transition state, i.e., of the properties that are commonly used to verify the quality of any exchange-correlation functional. However, the results of our AIMD calculations, which are performed at different incidence conditions and hence extensively probe the multi-configurational potential energy surface of the system, do not seem as satisfactory as the preliminary static analysis suggested. When comparing the obtained dissociation probabilities with existing experimental data, none of the used vdW-functionals seems to provide altogether an adequate description of the N{sub 2}/W(110) interaction at

  8. Accelerating rate calorimetry studies of the effect of binder type on the thermal stability of a lithiated mesocarbon microbead material in electrolyte

    NASA Astrophysics Data System (ADS)

    Richard, M. N.; Dahn, J. R.

    An Accelerating Rate Calorimeter (ARC) is used to measure the thermal behaviour of lithiated MCMB (mesocarbon microbead) electrodes, made with different binder, in electrolyte. Electrodes using PVDF, (VdF:HFP) or (VdF:CTFE) copolymer and ethylenepropylene-diene (EPD) terpolymer binders were studied. The safety results for the Vdf-based binder electrodes are almost identical, within error, suggesting that the safety of Li-ion cells is not compromised or improved by changes to the binder within this group. On the other hand, the electrodes made with EPD binder, that is not plasticized by the electrolyte, appear to have the lowest self-heating rates.

  9. The Nature of the Interlayer Interaction in Bulk and Few-Layer Phosphorus.

    PubMed

    Shulenburger, L; Baczewski, A D; Zhu, Z; Guan, J; Tománek, D

    2015-12-01

    Sensitive dependence of the electronic structure on the number of layers in few-layer phosphorene raises a question about the true nature of the interlayer interaction in so-called "van der Waals (vdW) solids". We performed quantum Monte Carlo calculations and found that the interlayer interaction in bulk black phosphorus and related few-layer phosphorene is associated with a significant charge redistribution that is incompatible with purely dispersive forces and not captured by density functional theory calculations with different vdW corrected functionals. These findings confirm the necessity of more sophisticated treatment of nonlocal electron correlation in total energy calculations.

  10. The effects of vitamin D3 on lipogenesis in the liver and adipose tissue of pregnant rats.

    PubMed

    Kang, Eun-Jin; Lee, Jae-Eon; An, Sung-Min; Lee, Jae Ho; Kwon, Hyeog Soong; Kim, Byoung Chul; Kim, Seon Jong; Kim, Joo Man; Hwang, Dae Youn; Jung, Young-Jin; Yang, Seung Yun; Kim, Seung Chul; An, Beum-Soo

    2015-10-01

    Obesity is a worldwide individual and public health issue, and contributes to the development of numerous chronic diseases. In particular, maternal obesity has harmful effects on both the mother and child during and after pregnancy. The digestion and metabolism of food are controlled by endocrine factors, including insulin, glucagon and estrogen. These hormonal factors are differentially regulated during pregnancy due to the specialized hormonal environment during this period. In the present study, we examined the effects of 1,25-dihydroxyvitamin D3 (VD3), an active hormonal form of nutritional vitamin D3, on lipid metabolism in pregnant rats. The body weight of rats treated with VD3 was significantly reduced compared to that of the rats in the control group. In addition, histological analysis demonstrated that the amount of fat stored in adipocytes was reduced by treatment with VD3. To determine the role of VD3 in lipid metabolism, the expression levels of lipid metabolism‑associated genes were measured in the rat adipose tissue and liver. VD3 negatively regulated the expression of various lipogenic genes, including fatty acid synthase (FAS), stearoyl-CoA desaturase 1 (SCD1) and acetyl-CoA carboxylase 1 (ACC1), in both the adipose tissue and liver. However, the regulators of lipogenic enzymes such as, sterol regulatory element-binding protein-1c (SREBP-1c), peroxisome proliferator-activated receptor-γ (PPAR-γ) and insulin-induced gene 2 (INSIG2) were differentially regulated by VD3 in a tissue‑specific manner. On the whole, these findings suggest that VD3 regulates lipid metabolism and deposition in the liver and adipose tissue, and thereby reduces fat in pregnant animals, as well as body weight. Our results suggest that the alteration of lipogenesis through the administration of VD3 may help to reduce excessive weight gain during pregnancy and prevent obesity‑related pregnancy complications such as pre-eclampsia, gestational diabetes

  11. The nature of the interlayer interaction in bulk and few-layer phosphorus

    DOE PAGES

    Shulenburger, Luke; Baczewski, A. D.; Zhu, Z.; Guan, J.; Tomanek, David

    2015-11-02

    Sensitive dependence of the electronic structure on the number of layers in few-layer phosphorene raises a question about the true nature of the interlayer interaction in so-called van der Waals (vdW) solids . We performed quantum Monte Carlo calculations and found that the interlayer interaction in bulk black phosphorus and related few-layer phosphorene is associated with a significant charge redistribution that is incompatible with purely dispersive forces and not captured by density functional theory calculations with different vdW corrected functionals. Lastly, these findings confirm the necessity of more sophisticated treatment of nonlocal electron correlation in total energy calculations.

  12. Interactions between surface discharges induced by volume discharges in a dielectric barrier discharge system

    SciTech Connect

    Gao, Yenan; Dong, Lifang Zhao, Longhu; Wang, Yongjie; Pan, Yuyang; Li, Ben

    2014-10-15

    The interaction between micro-discharges involved in surface discharges (SDs) is studied in dielectric barrier discharge system. Instantaneous images taken by high speed cameras show that the SDs are induced by volume discharges (VDs). They cannot cross the midperpendicular of two neighbouring volume charges at low voltage while they stretch along it at high voltage, indicating that there is interaction between SDs. The differences of plasma parameters between SD and VD are studied by optical emission spectroscopy. The simulation of the electric fields of the wall charges accumulated by VD further confirms the existence of the interaction.

  13. Communication: Non-additivity of van der Waals interactions between nanostructures

    SciTech Connect

    Tao, Jianmin; Perdew, John P.

    2014-10-14

    Due to size-dependent non-additivity, the van der Waals interaction (vdW) between nanostructures remains elusive. Here we first develop a model dynamic multipole polarizability for an inhomogeneous system that allows for a cavity. The model recovers the exact zero- and high-frequency limits and respects the paradigms of condensed matter physics (slowly varying density) and quantum chemistry (one- and two-electron densities). We find that the model can generate accurate vdW coefficients for both spherical and non-spherical clusters, with an overall mean absolute relative error of 4%, without any fitting. Based on this model, we study the non-additivity of vdW interactions. We find that there is strong non-additivity of vdW interactions between nanostructures, arising from electron delocalization, inequivalent contributions of atoms, and non-additive many-body interactions. Furthermore, we find that the non-additivity can have increasing size dependence as well as decreasing size dependence with cluster size.

  14. The effect of moderate hemodilution with fluosol-DA or normal saline on acetaminophen disposition in the rat.

    PubMed

    Shrewsbury, R P; White, L G

    1990-02-15

    Hemodilution with 40 ml/kg of Fluosol or saline reduced the acetaminophen Vd and the acetaminophen sulfate ClM at 48 or 72 h, respectively. Fluosol hemodilution increased the acetaminophen renal excretion at 24 and 72 h. But at 48 h, Fluosol hemodilution either inhibited the renal secretion of acetaminophen or enhanced its reabsorption.

  15. Prevalence and characterization of Chlamydia DNA in zoo animals in Japan.

    PubMed

    Kabeya, Hidenori; Sato, Shingo; Maruyama, Soichi

    2015-09-01

    Because many people visit zoos, prevention of zoonoses is important from the standpoint of public health. This study examined the prevalence of Chlamydia among zoo animals in Japan by PCR and characterized these bacteria by performing phylogenetic analyses of the sequences of the variable domain (VD) 2 and VD4 regions of the ompA gene, which encodes the Chlamydia major outer membrane protein. Fecal samples were collected from 1150 zoo animals in five zoos and examined for Chlamydia DNA. Chlamydia psittaci DNA was found in 3.9% of mammals, 7.2% of birds and 8.1% of reptiles. The prevalence of Chlamydia pneumoniae DNA was significantly higher in reptiles (5.8%) than in mammals (0.3%) and birds (0.3%). Phylogenetic analysis of the ompA VD2 region from 18 samples showed that nine were in three different clusters containing C. psittaci strains, six were in a cluster containing C. pneumoniae strains and three each formed a distinct branch. Furthermore, phylogenetic analysis of the ompA VD4 region showed that C. pneumoniae DNAs from reptiles were close to those from human patients. The C. pneumoniae DNAs from the European glass lizard, Emerald tree boa, and Panther chameleon were classified in clusters that were distinct from other strains, suggesting that these reptiles had each been infected with a specific C. pneumoniae genotype. This study showed that diverse Chlamydia strains have been prevalent among a variety of zoo animals. PMID:26215334

  16. Verbal Discrimination Learning of Items Read in Textual Material

    ERIC Educational Resources Information Center

    Zechmeister, Eugene B.; And Others

    1973-01-01

    The major question addressed in the present article was whether frequency experienced through a natural language activity, such as reading textual material, influences subsequent verbal discrimination (VD) learning in the same manner as that which has been demonstrated for other types of familiarization, e.g., free-recall learning - Underwood &…

  17. Electronic structures and enhanced optical properties of blue phosphorene/transition metal dichalcogenides van der Waals heterostructures

    NASA Astrophysics Data System (ADS)

    Peng, Qiong; Wang, Zhenyu; Sa, Baisheng; Wu, Bo; Sun, Zhimei

    2016-08-01

    As a fast emerging topic, van der Waals (vdW) heterostructures have been proposed to modify two-dimensional layered materials with desired properties, thus greatly extending the applications of these materials. In this work, the stacking characteristics, electronic structures, band edge alignments, charge density distributions and optical properties of blue phosphorene/transition metal dichalcogenides (BlueP/TMDs) vdW heterostructures were systematically studied based on vdW corrected density functional theory. Interestingly, the valence band maximum and conduction band minimum are located in different parts of BlueP/MoSe2, BlueP/WS2 and BlueP/WSe2 heterostructures. The MoSe2, WS2 or WSe2 layer can be used as the electron donor and the BlueP layer can be used as the electron acceptor. We further found that the optical properties under visible-light irradiation of BlueP/TMDs vdW heterostructures are significantly improved. In particular, the predicted upper limit energy conversion efficiencies of BlueP/MoS2 and BlueP/MoSe2 heterostructures reach as large as 1.16% and 0.98%, respectively, suggesting their potential applications in efficient thin-film solar cells and optoelectronic devices.

  18. Meta-analysis of plasma homocysteine content and cognitive function in elderly patients with Alzheimer’s disease and vascular dementia

    PubMed Central

    Wang, Beiyun; Zhong, Yuan; Yan, Hong; Cui, Liang

    2014-01-01

    Objective: To evaluate the relationship between homocysteine and cognitive function of Alzheimer’s disease (AD) patients and vascular dementia (VD) patients. Methods: By Cochrane system evaluation we retrieved relevant publications from MEDLINE, Embase, OVID, controlled clinical trial database of the Cochrane library and others. Two evaluators jointly assessed the research quality of the retrieved publications and carried out meta-analysis on the homogeneous study. Results: MMSE score in the AD group was lower than that in normal control group (MD = -11.98, 95% CI (-13.30, -10.65)), and the homocysteine content was higher than that in the normal control group (MD = 2.72, 95% CI (1.79, 3.64)), with a statistical difference between the two groups (P < 0.05). The homocysteine content in the AD group was higher than that in the VD group (MD = -4.76, 95% CI (-7.59, -1.93), P < 0.05). Conclusions: MSE score and homocysteine content can be used as useful indicators to distinguish AD and normal subjects; homocysteine content can be used as an indicator to differentiate AD from VD. Clinically, more randomized controlled trials are needed to test and verify the relationship in cognitive function between homocysteine and AD and VD. PMID:25664013

  19. Self-consistent treatment of the sheath boundary conditions by introducing anisotropic ion temperatures and virtual divertor model

    NASA Astrophysics Data System (ADS)

    Togo, Satoshi; Takizuka, Tomonori; Nakamura, Makoto; Hoshino, Kazuo; Ibano, Kenzo; Lang, Tee Long; Ogawa, Yuichi

    2016-04-01

    One-dimensional SOL-divertor plasma fluid simulation code which considers anisotropy of ion temperature has been developed so as to deal with sheath theory self-consistently. In our fluid modeling, explicit use of boundary condition for Mach number M at divertor plate, e.g., M = 1, becomes unnecessary. In order to deal with the Bohm condition and the sheath heat transmission factors at divertor plate self-consistently, we introduced a virtual divertor (VD) model which sets an artificial region beyond divertor plates and artificial sinks for particle, momentum and energy there to model the effects of the sheath region in front of the divertor plate. Validity of our fluid model with VD model is confirmed by showing that simulation results agree well with those from a kinetic code regarding the Bohm condition, ion temperature anisotropy and supersonic flow. We also show that the strength of artificial sinks in VD region does not affect profiles in plasma region at least in the steady state and that sheath heat transmission factors can be adjusted to theoretical values by VD model. Validity of viscous flux is also investigated.

  20. Density-functional description of polymer crystals: A comparative study of recent van der Waals functionals

    NASA Astrophysics Data System (ADS)

    Pham, Thinh H.; Ramprasad, Rampi; Nguyen, Huy-Viet

    2016-06-01

    Due to the lack of treatment of long-range dispersion energies, density functional theory with local and semilocal approximations of exchange-correlation energy is known to fail in describing van der Waals complexes, including polymer crystals. This limitation can be overcome by using a different class of functionals, called van der Waals density functional (vdW-DF), originally developed by Dion et al. [Phys. Rev. Lett. 92, 246401 (2004)]. In this work, we performed a systematic study of structural properties of polymeric crystals using the original vdW-DF functional by Dion et al. and its variants and refinements. Our study shows that this class of functional outperforms the conventional LDA or PBE functionals and gives results with similar accuracy to that of empirical dispersion-corrected schemes such as DFT-D. This study suggests the use of vdW-DF2 functional — a revised version of vdW-DF functional — to obtain a high-fidelity prediction of structural and other properties of polymeric materials.

  1. Persistent photoconductivity in two-dimensional Mo1-xW xSe2–MoSe2 van der Waals heterojunctions

    DOE PAGES

    Puretzky, Alexander A.; Basile, Leonardo; Idrobo, Juan Carlos; Rouleau, Christopher M.; Geohegan, David B.; Xiao, Kai; Li, Xufan; Lin, Ming -Wei; Wang, Kei

    2016-02-16

    Van der Waals (vdW) heterojunctions consisting of vertically-stacked individual or multiple layers of two-dimensional (2D) layered semiconductors, especially the transition metal dichalcogenides (TMDs), are fascinating new artificial solids just nanometers-thin that promise novel optoelectronic functionalities due to the sensitivity of their electronic and optical properties to strong quantum confinement and interfacial interactions. Here, monolayers of n-type MoSe2 and p-type Mo1-xW xSe2–MoSe2 are grown by vapor transport methods, then transferred and stamped to form artificial vdW heterostructures with different interlayer orientations. Atomic-resolution Z-contrast electron microscopy and electron diffraction are used to characterize both the individual monolayers and the atomic registry betweenmore » layers in the bilayer vdW heterostructures. These measurements are compared with photoluminescence and low-frequency Raman spectroscopy, which indicates strong interlayer coupling in heterostructures. Remarkably, the heterojunctions exhibit an unprecedented photoconductivity effect that persists at room temperature for several days. This persistent photoconductivity is shown to be tunable by applying a gate bias that equilibrates the charge distribution. Furthermore, these measurements indicate that such ultrathin vdW heterojunctions can function as rewritable optoelectronic switches or memory elements under time-dependent photo-illumination, an effect which appears promising for new monolayer TMDs-based optoelectronic devices applications.« less

  2. Comparison of Alternative Schedules for Producing Productive Workshop Behaviour in a Person with an Intellectual Handicap.

    ERIC Educational Resources Information Center

    Alexander, Gerald; Beale, Ivan L.

    1990-01-01

    An intellectually handicapped man was studied in a workshop where he was employed to "detip" ear tags. Productive behavior was reinforced on either a variable ratio (VR) schedule or a variable duration (VD) schedule. Results indicated lower time on task and higher detipping rates under the VR schedule. (Author/PB)

  3. Dry deposition of O3 and SO2 estimated from gradient measurements above a temperate mixed forest.

    PubMed

    Wu, Zhiyong; Staebler, Ralf; Vet, Robert; Zhang, Leiming

    2016-03-01

    Vertical profiles of O3 and SO2 concentrations were monitored at the Borden Forest site in southern Ontario, Canada from May 2008 to April 2013. A modified gradient method (MGM) was applied to estimate O3 and SO2 dry deposition fluxes using concentration gradients between a level above and a level below the canopy top. The calculated five-year mean (median) dry deposition velocity (Vd) were 0.35 (0.27) and 0.59 (0.54) cm s(-1), respectively, for O3 and SO2. Vd(O3) exhibited large seasonal variations with the highest monthly mean of 0.68 cm s(-1) in August and the lowest of 0.09 cm s(-1) in February. In contrast, seasonal variations of Vd(SO2) were smaller with monthly means ranging from 0.48 (May) to 0.81 cm s(-1) (December). The different seasonal variations between O3 and SO2 were caused by the enhanced SO2 uptake by snow surfaces in winter. Diurnal variations showed a peak value of Vd in early morning in summer months for both O3 and SO2. Canopy wetness increased the non-stomatal uptake of O3 while decreasing the stomatal uptake. This also applied to SO2, but additional factors such as surface acidity also played an important role on the overall uptake.

  4. Two-compartment, two-sample technique for accurate estimation of effective renal plasma flow: Theoretical development and comparison with other methods

    SciTech Connect

    Lear, J.L.; Feyerabend, A.; Gregory, C.

    1989-08-01

    Discordance between effective renal plasma flow (ERPF) measurements from radionuclide techniques that use single versus multiple plasma samples was investigated. In particular, the authors determined whether effects of variations in distribution volume (Vd) of iodine-131 iodohippurate on measurement of ERPF could be ignored, an assumption implicit in the single-sample technique. The influence of Vd on ERPF was found to be significant, a factor indicating an important and previously unappreciated source of error in the single-sample technique. Therefore, a new two-compartment, two-plasma-sample technique was developed on the basis of the observations that while variations in Vd occur from patient to patient, the relationship between intravascular and extravascular components of Vd and the rate of iodohippurate exchange between the components are stable throughout a wide range of physiologic and pathologic conditions. The new technique was applied in a series of 30 studies in 19 patients. Results were compared with those achieved with the reference, single-sample, and slope-intercept techniques. The new two-compartment, two-sample technique yielded estimates of ERPF that more closely agreed with the reference multiple-sample method than either the single-sample or slope-intercept techniques.

  5. 25-hydroxyvitamin D levels and juvenile idiopathic arthritis: is there an association with disease activity?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To examine the association between serum levels of 25-hydroxyvitamin D [25(OH)D] and disease activity in juvenile idiopathic arthritis (JIA), to determine the prevalence of vitamin D (VD) deficiency [25(OH)D=19 ng/ml] and insufficiency [25(OH)D 20-29 ng/ml], and to determine factors associated with ...

  6. On the anisotropy of van der Waals atomic radii of O, S, Se, F, Cl, Br, and I.

    PubMed

    Eramian, Hamed; Tian, Yong-Hui; Fox, Zach; Beneberu, Habtamu Z; Kertesz, Miklos

    2013-12-27

    The Cambridge Structural Database (CSD) was used to obtain flattening factors to describe the overall anisotropy of nonbonding van der Waals (vdW) contacts between several main group elements. The method for obtaining the flattening factors is based on a novel minimization process. Results show that the vdW contact distances are significantly dependent on the environment and the orientations of the surrounding covalently bonded atoms: head-on vdW contacts are generally shorter than sideways contacts in overall agreement with earlier results by Nyburg and Faerman (Acta Crystallogr., Sect. B: Struct. Sci. 1985, 41, 274-279). With the exception of Se, we find flattening factors that are somewhat smaller than those found earlier. High-level ab initio quantum chemical calculations using Ar and Ne as a probe also confirm the flattening effect and its dependency on the environment. A dozen popular long-range corrected and dispersion supplemented density functionals are compared with the CCSD(T) data. While several of them perform quite poorly, four DFT-D methods, especially B3LYP-GD3BJ, provided vdW flattening similar to those found by the CCSD(T) theory and experiment. PMID:24283380

  7. Density-functional description of polymer crystals: A comparative study of recent van der Waals functionals.

    PubMed

    Pham, Thinh H; Ramprasad, Rampi; Nguyen, Huy-Viet

    2016-06-01

    Due to the lack of treatment of long-range dispersion energies, density functional theory with local and semilocal approximations of exchange-correlation energy is known to fail in describing van der Waals complexes, including polymer crystals. This limitation can be overcome by using a different class of functionals, called van der Waals density functional (vdW-DF), originally developed by Dion et al. [Phys. Rev. Lett. 92, 246401 (2004)]. In this work, we performed a systematic study of structural properties of polymeric crystals using the original vdW-DF functional by Dion et al. and its variants and refinements. Our study shows that this class of functional outperforms the conventional LDA or PBE functionals and gives results with similar accuracy to that of empirical dispersion-corrected schemes such as DFT-D. This study suggests the use of vdW-DF2 functional - a revised version of vdW-DF functional - to obtain a high-fidelity prediction of structural and other properties of polymeric materials. PMID:27276968

  8. Toward a Systematic Evaluation of Vowel Target Events across Speech Tasks

    ERIC Educational Resources Information Center

    Kuo, Christina

    2011-01-01

    The core objective of this study was to examine whether acoustic variability of vowel production in American English, across speaking tasks, is systematic. Ten male speakers who spoke a relatively homogeneous Wisconsin dialect produced eight monophthong vowels (in hVd and CVC contexts) in four speaking tasks, including clear-speech, citation form,…

  9. Microorganism-induced exacerbations in atopic dermatitis: a possible preventive role for vitamin D?

    PubMed

    Benetti, Cecilia; Piacentini, Giorgio L; Capristo, Carlo; Boner, Attilio L; Peroni, Diego G

    2015-01-01

    Atopic dermatitis (AD) is a common skin disease characterized by a complex pathogenesis not completely understood despite numerous studies to date. The clinical patterns result from interactions between genetic disorders determining abnormalities in the epidermis differentiation complex, modification of the cutaneous barrier, and dysfunction of immune responses. Several studies have shown that an alteration of the skin barrier combined with immune dysfunction is important for the onset, maintenance, and risk of exacerbations of the disease. In recent years, new aspects regarding the pathogenesis of the disease, such as the effects of vitamin D (VD) on immunity at the skin level and the role of certain microorganisms (particularly Staphylococcus and Malassezia species) on eczema exacerbations, have been evaluated. This article provides an overview of the evidences supporting the link between VD (deficiency) and microorganisms (skin colonization/sensitization) in AD pathogenesis, based on comprehensive review of the literature. By considering different aspects of disease, it might be possible to improve our understanding, particularly in those patients refractory to conventional treatments. An electronic research strategy was used to search in Medline Pub-Med Library using as research words AD, exacerbation, VD, Staphylococcus aureus (SA), and Malassezia. The results were downloaded and analyzed for systematic review. Few studies actually consider the relationship between VD deficiency (VDD), AD, and SA and Malassezia, but many suggest a correlation between these factors. VDs play a major role against microorganisms in the development of AD and should be considered when treating patients. PMID:25562552

  10. How many-body effects modify the van der Waals interaction between graphene sheets

    NASA Astrophysics Data System (ADS)

    Dobson, John; Gould, Tim; Vignale, Giovanni

    2014-03-01

    Cold undoped graphene sheets were previously predicted, via Random Phase approximation (RPA) arguments, to exhibit an unusual asymptotic van der Waals (vdW) interaction energy E = - KD-3 where D is the (large) separation between the two parallel graphene sheets. This is compared with D - 5 / 2 for 2D metals and D-4 for 2D insulators. Here we show that graphene is the first known system where effects beyond the RPA should make QUALITATIVE changes to the vdW force. For large separations, D > 10 nm where only πz-mediated vdW forces remain, we predict that the vdW interaction is substantially reduced from the RPA prediction, and has a different power law. This new D dependence is very sensitive to the form of the long-wavelength many-body renormalization of the velocity of the massless Dirac fermions, and may provide independent confirmation of the latter. We will briefly discuss issues involved in possible experiments. Work supported by the Australian Research Council, NSF and DIPC.

  11. Transposable elements in phytopathogenic Verticillium spp.: insights into genome evolution and inter- and intra-specific diversification

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Verticillium dahliae (Vd) and Verticillium albo-atrum (Va) are cosmopolitan soil fungi causing very disruptive vascular diseases on a wide range of crop plants. To date, no sexual stage has been identified in either microorganism suggesting that somatic mutation is a major force in generating geneti...

  12. Effect of van der Waals corrections on DFT-computed metallic surface properties

    NASA Astrophysics Data System (ADS)

    Chiter, Fatah; Bac Nguyen, Van; Tarrat, Nathalie; Benoit, Magali; Tang, Hao; Lacaze-Dufaure, Corinne

    2016-04-01

    State-of-the-art van der Waals (vdW) corrected density functional theory (DFT) is routinely used to overcome the failure of standard DFT in the description of molecule/surface long range interactions. However, the systematic use of dispersion forces to model metallic surfaces could lead to less accurate results than the standard DFT and the effect of these corrections on the metal properties should be properly evaluated. In this framework, the behavior of two widely used vdW corrected DFT methods (DFT-D2 and vdW-DF/optB86b) has been evaluated on six metals, i.e. Al, Cu, Au, Ni, Co and Fe, with respect to standard GGA-DFT and experiments. Regarding bulk properties, general trends are found for the lattice parameter, cohesive energy and magnetic moment variations when the vdW correction is introduced. Surface energies, work functions and interlayer distances of closed packed surfaces, Al(111), Cu(111), Au(111) and magnetic Ni(111), Co(0001) and Fe(110), are also strongly affected by the dispersion forces. These modifications suggest a systematic verification of the surface properties when a dispersion correction is included.

  13. 14 CFR 25.351 - Yaw maneuver conditions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...) With the airplane in unaccelerated flight at zero yaw, it is assumed that the cockpit rudder control is... to VD/MD, with a linear variation between VA and VC/MC. (b) With the cockpit rudder control deflected...) With the airplane yawed to the static equilibrium sideslip angle, it is assumed that the cockpit...

  14. Diffuse-interface modeling of liquid-vapor coexistence in equilibrium drops using smoothed particle hydrodynamics

    NASA Astrophysics Data System (ADS)

    Sigalotti, Leonardo Di G.; Troconis, Jorge; Sira, Eloy; Peña-Polo, Franklin; Klapp, Jaime

    2014-07-01

    We study numerically liquid-vapor phase separation in two-dimensional, nonisothermal, van der Waals (vdW) liquid drops using the method of smoothed particle hydrodynamics (SPH). In contrast to previous SPH simulations of drop formation, our approach is fully adaptive and follows the diffuse-interface model for a single-component fluid, where a reversible, capillary (Korteweg) force is added to the equations of motion to model the rapid but smooth transition of physical quantities through the interface separating the bulk phases. Surface tension arises naturally from the cohesive part of the vdW equation of state and the capillary forces. The drop models all start from a square-shaped liquid and spinodal decomposition is investigated for a range of initial densities and temperatures. The simulations predict the formation of stable, subcritical liquid drops with a vapor atmosphere, with the densities and temperatures of coexisting liquid and vapor in the vdW phase diagram closely matching the binodal curve. We find that the values of surface tension, as determined from the Young-Laplace equation, are in good agreement with the results of independent numerical simulations and experimental data. The models also predict the increase of the vapor pressure with temperature and the fitting to the numerical data reproduces very well the Clausius-Clapeyron relation, thus allowing for the calculation of the vaporization pressure for this vdW fluid.

  15. Conserved molecular mechanisms underlying the effects of small molecule xenobiotic chemotherapeutics on cells

    PubMed Central

    SARIN, HEMANT

    2016-01-01

    For proper determination of the apoptotic potential of chemoxenobiotics in synergism, it is important to understand the modes, levels and character of interactions of chemoxenobiotics with cells in the context of predicted conserved biophysical properties. Chemoxenobiotic structures are studied with respect to atom distribution over molecular space, the predicted overall octanol-to-water partition coefficient (Log OWPC; unitless) and molecular size viz a viz van der Waals diameter (vdWD). The Log OWPC-to-vdWD (nm−1) parameter is determined, and where applicable, hydrophilic interacting moiety/core-to-vdWD (nm−1) and lipophilic incorporating hydrophobic moiety/core-to-vdWD (nm−1) parameters of their part-structures are determined. The cellular and sub-cellular level interactions of the spectrum of xenobiotic chemotherapies have been characterized, for which a classification system has been developed based on predicted conserved biophysical properties with respect to the mode of chemotherapeutic effect. The findings of this study are applicable towards improving the effectiveness of existing combination chemotherapy regimens and the predictive accuracy of personalized cancer treatment algorithms as well as towards the selection of appropriate novel xenobiotics with the potential to be potent chemotherapeutics for dendrimer nanoparticle-based effective transvascular delivery. PMID:26998284

  16. Fluorinated graphene and hexagonal boron nitride as ALD seed layers for graphene-based van der Waals heterostructures

    NASA Astrophysics Data System (ADS)

    Guo, Hongwei; Liu, Yunlong; Xu, Yang; Meng, Nan; Wang, Hongtao; Hasan, Tawfique; Wang, Xinran; Luo, Jikui; Yu, Bin

    2014-09-01

    Ultrathin dielectric materials prepared by atomic-layer-deposition (ALD) technology are commonly used in graphene electronics. Using the first-principles density functional theory calculations with van der Waals (vdW) interactions included, we demonstrate that single-side fluorinated graphene (SFG) and hexagonal boron nitride (h-BN) exhibit large physical adsorption energy and strong electrostatic interactions with H2O-based ALD precursors, indicating their potential as the ALD seed layer for dielectric growth on graphene. In graphene-SFG vdW heterostructures, graphene is n-doped after ALD precursor adsorption on the SFG surface caused by vertical intrinsic polarization of SFG. However, graphene-h-BN vdW heterostructures help preserving the intrinsic characteristics of the underlying graphene due to in-plane intrinsic polarization of h-BN. By choosing SFG or BN as the ALD seed layer on the basis of actual device design needs, the graphene vdW heterostructures may find applications in low-dimensional electronics.

  17. Fluorinated graphene and hexagonal boron nitride as ALD seed layers for graphene-based van der Waals heterostructures.

    PubMed

    Guo, Hongwei; Liu, Yunlong; Xu, Yang; Meng, Nan; Wang, Hongtao; Hasan, Tawfique; Wang, Xinran; Luo, Jikui; Yu, Bin

    2014-09-01

    Ultrathin dielectric materials prepared by atomic-layer-deposition (ALD) technology are commonly used in graphene electronics. Using the first-principles density functional theory calculations with van der Waals (vdW) interactions included, we demonstrate that single-side fluorinated graphene (SFG) and hexagonal boron nitride (h-BN) exhibit large physical adsorption energy and strong electrostatic interactions with H2O-based ALD precursors, indicating their potential as the ALD seed layer for dielectric growth on graphene. In graphene-SFG vdW heterostructures, graphene is n-doped after ALD precursor adsorption on the SFG surface caused by vertical intrinsic polarization of SFG. However, graphene-h-BN vdW heterostructures help preserving the intrinsic characteristics of the underlying graphene due to in-plane intrinsic polarization of h-BN. By choosing SFG or BN as the ALD seed layer on the basis of actual device design needs, the graphene vdW heterostructures may find applications in low-dimensional electronics. PMID:25116064

  18. Younger Adults Show Long-Term Effects of Cognitive Training on Broad Cognitive Abilities over 2 Years

    ERIC Educational Resources Information Center

    Schmiedek, Florian; Lövdén, Martin; Lindenberger, Ulman

    2014-01-01

    In the COGITO study (Schmiedek, Lövdén, & Lindenberger, 2010), 101 younger adults practiced 12 tests of perceptual speed, working memory, and episodic memory for over 100 daily 1-hr sessions. The intervention resulted in positive transfer to broad cognitive abilities, including reasoning and episodic memory. Here, we examine whether these…

  19. Electronic structures and enhanced optical properties of blue phosphorene/transition metal dichalcogenides van der Waals heterostructures.

    PubMed

    Peng, Qiong; Wang, Zhenyu; Sa, Baisheng; Wu, Bo; Sun, Zhimei

    2016-01-01

    As a fast emerging topic, van der Waals (vdW) heterostructures have been proposed to modify two-dimensional layered materials with desired properties, thus greatly extending the applications of these materials. In this work, the stacking characteristics, electronic structures, band edge alignments, charge density distributions and optical properties of blue phosphorene/transition metal dichalcogenides (BlueP/TMDs) vdW heterostructures were systematically studied based on vdW corrected density functional theory. Interestingly, the valence band maximum and conduction band minimum are located in different parts of BlueP/MoSe2, BlueP/WS2 and BlueP/WSe2 heterostructures. The MoSe2, WS2 or WSe2 layer can be used as the electron donor and the BlueP layer can be used as the electron acceptor. We further found that the optical properties under visible-light irradiation of BlueP/TMDs vdW heterostructures are significantly improved. In particular, the predicted upper limit energy conversion efficiencies of BlueP/MoS2 and BlueP/MoSe2 heterostructures reach as large as 1.16% and 0.98%, respectively, suggesting their potential applications in efficient thin-film solar cells and optoelectronic devices.

  20. Electronic structures and enhanced optical properties of blue phosphorene/transition metal dichalcogenides van der Waals heterostructures.

    PubMed

    Peng, Qiong; Wang, Zhenyu; Sa, Baisheng; Wu, Bo; Sun, Zhimei

    2016-01-01

    As a fast emerging topic, van der Waals (vdW) heterostructures have been proposed to modify two-dimensional layered materials with desired properties, thus greatly extending the applications of these materials. In this work, the stacking characteristics, electronic structures, band edge alignments, charge density distributions and optical properties of blue phosphorene/transition metal dichalcogenides (BlueP/TMDs) vdW heterostructures were systematically studied based on vdW corrected density functional theory. Interestingly, the valence band maximum and conduction band minimum are located in different parts of BlueP/MoSe2, BlueP/WS2 and BlueP/WSe2 heterostructures. The MoSe2, WS2 or WSe2 layer can be used as the electron donor and the BlueP layer can be used as the electron acceptor. We further found that the optical properties under visible-light irradiation of BlueP/TMDs vdW heterostructures are significantly improved. In particular, the predicted upper limit energy conversion efficiencies of BlueP/MoS2 and BlueP/MoSe2 heterostructures reach as large as 1.16% and 0.98%, respectively, suggesting their potential applications in efficient thin-film solar cells and optoelectronic devices. PMID:27553787

  1. How van der Waals interactions determine the unique properties of water.

    PubMed

    Morawietz, Tobias; Singraber, Andreas; Dellago, Christoph; Behler, Jörg

    2016-07-26

    Whereas the interactions between water molecules are dominated by strongly directional hydrogen bonds (HBs), it was recently proposed that relatively weak, isotropic van der Waals (vdW) forces are essential for understanding the properties of liquid water and ice. This insight was derived from ab initio computer simulations, which provide an unbiased description of water at the atomic level and yield information on the underlying molecular forces. However, the high computational cost of such simulations prevents the systematic investigation of the influence of vdW forces on the thermodynamic anomalies of water. Here, we develop efficient ab initio-quality neural network potentials and use them to demonstrate that vdW interactions are crucial for the formation of water's density maximum and its negative volume of melting. Both phenomena can be explained by the flexibility of the HB network, which is the result of a delicate balance of weak vdW forces, causing, e.g., a pronounced expansion of the second solvation shell upon cooling that induces the density maximum. PMID:27402761

  2. van der Waals density functionals built upon the electron-gas tradition: Facing the challenge of competing interactions

    SciTech Connect

    Berland, Kristian; Arter, Calvin A.; Thonhauser, T.; Cooper, Valentino R.; Lee, Kyuho; Lundqvist, Bengt I.; Schröder, Elsebeth; Hyldgaard, Per

    2014-05-14

    The theoretical description of sparse matter attracts much interest, in particular for those ground-state properties that can be described by density functional theory. One proposed approach, the van der Waals density functional (vdW-DF) method, rests on strong physical foundations and offers simple yet accurate and robust functionals. A very recent functional within this method called vdW-DF-cx [K. Berland and P. Hyldgaard, Phys. Rev. B 89, 035412 (2014)] stands out in its attempt to use an exchange energy derived from the same plasmon-based theory from which the nonlocal correlation energy was derived. Encouraged by its good performance for solids, layered materials, and aromatic molecules, we apply it to several systems that are characterized by competing interactions. These include the ferroelectric response in PbTiO{sub 3}, the adsorption of small molecules within metal-organic frameworks, the graphite/diamond phase transition, and the adsorption of an aromatic-molecule on the Ag(111) surface. Our results indicate that vdW-DF-cx is overall well suited to tackle these challenging systems. In addition to being a competitive density functional for sparse matter, the vdW-DF-cx construction presents a more robust general-purpose functional that could be applied to a range of materials problems with a variety of competing interactions.

  3. van der Waals density functionals built upon the electron-gas tradition: Facing the challenge of competing interactions

    SciTech Connect

    Berland, Kristian; Arter, Calvin A; Cooper, Valentino R; Lee, Dr. Kyuho; Lundqvist, Prof. Bengt I.; Schroder, Prof. Elsebeth; Thonhauser, Prof. Timo; Hyldgaard, Per

    2014-01-01

    The theoretical description of sparse matter attracts much interest, in particular for those groundstate properties that can be described by density functional theory (DFT). One proposed approach, the van der Waals density functional (vdW-DF) method, rests on strong physical foundations and offers simple yet accurate and robust functionals. A very recent functional within this method called vdW-DF-cx [K. Berland and P. Hyldgaard, Phys. Rev. B, in print] stands out in its attempt to use an exchange energy derived from the same plasmon-based theory from which the nonlocal correlation energy was derived. Encouraged by its good performance for solids, layered materials, and aromatic molecules, we apply it to several systems that are characterized by competing interactions. These include the ferroelectric response in PbTiO3, the adsorption of small molecules within metal-organic frameworks (MOFs), the graphite/diamond phase transition, and the adsorption of an aromaticmolecule on the Ag(111) surface. Our results indicate that vdW-DF-cx is overall well suited to tackle these challenging systems. In addition to being a competitive density functional for sparse matter, the vdW-DF-cx construction presents a more robust general purpose functional that could be applied to a range of materials problems with a variety of competing interactions.

  4. Root system architecture and gravitropism in the oil palm.

    PubMed

    Jourdan, C; Michaux-Ferriere, N; Perbal, G

    2000-06-01

    The oil palm (Elaeis guineensis Jacq.) has a root system consisting of primary (or order 1) roots, which are either orthogravitropic (R1 VD, with positive gravitropism) or diagravitropic (R1 H). Their statenchyma have very similar characteristics (mainly vacuolated, large cells). However, their statoliths sediment along the longitudinal wall in R1 H and along the distal wall in R1 VD (furthest cell wall from the apical meristem, opposite the proximal wall). Order 2 roots may have vertical upward (R2 VU) or downward growth (R2 VD) or even horizontal growth (R2 H). In all cases, the statoliths are located near the lower wall of the statocyte (distal in R2 VD, proximal in R2 VU and longitudinal in R2 H). Order 3 roots are usually agravitropic. When they grow upwards, R3 VU, their amyloplasts are located near the proximal wall. Likewise, the growth direction of R4 varies, but they have little or no statolith sedimentation. Roots with marked gravitropism (positive or negative) have amyloplasts that can sediment along different walls. But, irrespective of amyloplast position in the statocytes, the direction of root growth may be stable. The relation between the different reactions of roots and different sensitivity to auxin or to a curvature-halting signal is discussed.

  5. Diffuse-interface modeling of liquid-vapor coexistence in equilibrium drops using smoothed particle hydrodynamics.

    PubMed

    Sigalotti, Leonardo Di G; Troconis, Jorge; Sira, Eloy; Peña-Polo, Franklin; Klapp, Jaime

    2014-07-01

    We study numerically liquid-vapor phase separation in two-dimensional, nonisothermal, van der Waals (vdW) liquid drops using the method of smoothed particle hydrodynamics (SPH). In contrast to previous SPH simulations of drop formation, our approach is fully adaptive and follows the diffuse-interface model for a single-component fluid, where a reversible, capillary (Korteweg) force is added to the equations of motion to model the rapid but smooth transition of physical quantities through the interface separating the bulk phases. Surface tension arises naturally from the cohesive part of the vdW equation of state and the capillary forces. The drop models all start from a square-shaped liquid and spinodal decomposition is investigated for a range of initial densities and temperatures. The simulations predict the formation of stable, subcritical liquid drops with a vapor atmosphere, with the densities and temperatures of coexisting liquid and vapor in the vdW phase diagram closely matching the binodal curve. We find that the values of surface tension, as determined from the Young-Laplace equation, are in good agreement with the results of independent numerical simulations and experimental data. The models also predict the increase of the vapor pressure with temperature and the fitting to the numerical data reproduces very well the Clausius-Clapeyron relation, thus allowing for the calculation of the vaporization pressure for this vdW fluid. PMID:25122383

  6. Diffuse-interface modeling of liquid-vapor coexistence in equilibrium drops using smoothed particle hydrodynamics

    NASA Astrophysics Data System (ADS)

    Klapp, Jaime; di G Sigalotti, Leonardo; Troconis, Jorge; Sira, Eloy; Pena, Franklin; ININ-IVIC Team; Cinvestav-UAM-A Team

    2014-11-01

    We study numerically liquid-vapor phase separation in two-dimensional, nonisothermal, van der Waals (vdW) liquid drops using the method of Smoothed Particle Hydrodynamics (SPH). In contrast to previous SPH simulations of drop formation, our approach is fully adaptive and follows the diffuse interface model for a single-component fluid, where a reversible, capillary (Korteweg) force is added to the equations of motion to model the rapid but smooth transition of physical quantities through the interface separating the bulk phases. Surface tension arises naturally from the cohesive part of the vdW equation of state and the capillary forces. The drop models all start from a square-shaped liquid and spinodal decomposition is investigated for a range of initial densities and temperatures. The simulations predict the formation of stable, subcritical liquid drops with a vapor atmosphere, with the densities and temperatures of coexisting liquid and vapor in the vdW phase diagram closely matching the binodal curve. We find that the values of surface tension, as determined from the Young-Laplace equation, are in good agreement with the results of independent numerical simulations and experimental data. The models also predict the increase of the vapor pressure with temperature and the fitting to the numerical data reproduces very well the Clausius-Clapeyron relation, thus allowing for the calculation of the vaporization pressure for this vdW fluid. Cinvestav-Abacus.

  7. Intrapartum Cervical Laceration and Subsequent Pregnancy Outcomes

    PubMed Central

    Wong, Luchin F.; Wilkes, Jacob; Korgenski, Kent; Varner, Michael W.; Manuck, Tracy A.

    2016-01-01

    Objective The objective of this study was to describe pregnancy outcomes, including cervical insufficiency and preterm birth, in the subsequent pregnancy following an intrapartum cervical laceration. Study Design Retrospective cohort of women with their first two consecutive singleton pregnancies carried to ≥ 200/7 weeks' gestation within a tertiary health care system from 2002 to 2012. Cervical laceration cases were identified by ICD9 codes and included if suture repair was required. Results In this study, 55 women were confirmed to have a cervical laceration in the first delivery; 43 lacerations after vaginal delivery (VD) and 12 after cesarean delivery (CD). The median gestational age of the first delivery was 400/7 weeks and the median birth weight 3,545 g; these did not differ between VD and CD. In the second pregnancy, 2 of 55 women (4.6%) had a prophylactic cerclage placed; 1 carried to term and the other delivered at 356/7 weeks. In total, four women (9.3%) delivered the second pregnancy < 37 weeks: three had a prior term VD and one had a prior 34 weeks VD. There was only one case of recurrent cervical laceration, occurring in the setting of vaginal deliveries. Conclusion Obstetric cervical lacerations are uncommon. Complications in the following pregnancy were low, despite lack of additional prophylactic cerclage use. PMID:27621953

  8. Teaching About Sexually Transmitted Diseases; A Curriculum Guide and Resources For Grades 7-12.

    ERIC Educational Resources Information Center

    California State Dept. of Education, Sacramento.

    This curriculum guide provides school districts that already have VD education programs with up-to-date information about research and epidemiology relating to sexually transmitted diseases. For districts wishing to implement a program for the first time, it offers both a structured framework and the resources and materials needed for a complete…

  9. Thickness dependence of surface energy and contact angle of water droplets on ultrathin MoS2 films.

    PubMed

    Guo, Yanhua; Wang, Zhengfei; Zhang, Lizhi; Shen, Xiaodong; Liu, Feng

    2016-06-01

    We have performed a systematic density functional study of surface energy of MoS2 films as a function of thickness from one to twelve layers with the consideration of van der Waals (vdW) interactions using the vdW-DF and DFT-D2 methods. Both vdW schemes show that the surface energy will increase with the increase of the number of atomic layers and converge to a constant value at about six layers. Based on the calculated surface energies, we further analyze the surface contact angle of water droplets on the MoS2 film surface using Young's equation as a function of thickness in comparison with experiments, from which the water-MoS2 interfacial energy is derived to be independent of MoS2 thickness. Our calculations indicate that the vdW interactions between the MoS2 layers play an important role in determining surface energy, and results in the thickness dependence of the contact angle of water droplets on the MoS2 film surface. Our results explain well the recent wetting experiment [Nano Lett., 2014, 14(8), 4314], and will be useful for future studies of physical and chemical properties of ultrathin MoS2 films.

  10. 1-FFT amino acids involved in high DP inulin accumulation in Viguiera discolor

    PubMed Central

    De Sadeleer, Emerik; Vergauwen, Rudy; Struyf, Tom; Le Roy, Katrien; Van den Ende, Wim

    2015-01-01

    Fructans are important vacuolar reserve carbohydrates with drought, cold, ROS and general abiotic stress mediating properties. They occur in 15% of all flowering plants and are believed to display health benefits as a prebiotic and dietary fiber. Fructans are synthesized by specific fructosyltransferases and classified based on the linkage type between fructosyl units. Inulins, one of these fructan types with β(2-1) linkages, are elongated by fructan:fructan 1-fructosyltransferases (1-FFT) using a fructosyl unit from a donor inulin to elongate the acceptor inulin molecule. The sequence identity of the 1-FFT of Viguiera discolor (Vd) and Helianthus tuberosus (Ht) is 91% although these enzymes produce distinct fructans. The Vd 1-FFT produces high degree of polymerization (DP) inulins by preferring the elongation of long chain inulins, in contrast to the Ht 1-FFT which prefers small molecules (DP3 or 4) as acceptor. Since higher DP inulins have interesting properties for industrial, food and medical applications, we report here on the influence of two amino acids on the high DP inulin production capacity of the Vd 1-FFT. Introducing the M19F and H308T mutations in the active site of the Vd 1-FFT greatly reduces its capacity to produce high DP inulin molecules. Both amino acids can be considered important to this capacity, although the double mutation had a much higher impact than the single mutations. PMID:26322058

  11. Identification of pathogenicity-related genes in the vascular wilt fungus Verticillium dahliae by Agrobacterium tumefaciens-mediated T-DNA insertional mutagenesis.

    PubMed

    Maruthachalam, K; Klosterman, S J; Kang, S; Hayes, R J; Subbarao, K V

    2011-11-01

    Verticillium dahliae is the causal agent of vascular wilt in many economically important crops worldwide. Identification of genes that control pathogenicity or virulence may suggest targets for alternative control methods for this fungus. In this study, Agrobacterium tumefaciens-mediated transformation (ATMT) was applied for insertional mutagenesis of V. dahliae conidia. Southern blot analysis indicated that T-DNAs were inserted randomly into the V. dahliae genome and that 69% of the transformants were the result of single copy T-DNA insertion. DNA sequences flanking T-DNA insertion were isolated through inverse PCR (iPCR), and these sequences were aligned to the genome sequence to identify the genomic position of insertion. V. dahliae mutants of particular interest selected based on culture phenotypes included those that had lost the ability to form microsclerotia and subsequently used for virulence assay. Based on the virulence assay of 181 transformants, we identified several mutant strains of V. dahliae that did not cause symptoms on lettuce plants. Among these mutants, T-DNA was inserted in genes encoding an endoglucanase 1 (VdEg-1), a hydroxyl-methyl glutaryl-CoA synthase (VdHMGS), a major facilitator superfamily 1 (VdMFS1), and a glycosylphosphatidylinositol (GPI) mannosyltransferase 3 (VdGPIM3). These results suggest that ATMT can effectively be used to identify genes associated with pathogenicity and other functions in V. dahliae.

  12. Anaerobic soil disinfestation disease control performance in strawberry as influenced by environmental variables

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sustainability of the California strawberry industry is challenged by soil-borne diseases caused by Fusarium oxysporum (Fo), Macrophomina phaseolina (Mp) and Verticillium dahliae (Vd). Anaerobic soil disinfestation (ASD) has been studied as a non-fumigant measure for control of these diseases. This ...

  13. Specific identification of coconut tinangaja viroid for differential field diagnosis of viroids in coconut palm.

    PubMed

    Hodgson, R A; Wall, G C; Randles, J W

    1998-08-01

    ABSTRACT Tinangaja is a widespread lethal disease of putative viroid etiology affecting coconut palm on the island of Guam. Determination of its distribution and mode of spread requires a simple and reliable diagnostic procedure that is specific for the associated coconut tinangaja viroid (CTiVd). A method of extracting tissue followed by analytical agarose gel electrophoresis for CTiVd detection has been developed and used to identify the viroid in leaf samples of suspect symptomatic palms growing in the field. Two-dimensional polyacrylamide gel electrophoresis showed that the viroid band contained circular molecules that are typical for viroids. Confirmation of the identity of CTiVd and detection of low levels of viroid below the threshold of detection by agarose gel electrophoresis was achieved either by diagnostic oligonucleotide-probe (DOP) hybridization assay or by reverse-transcription polymerase chain reaction (RT-PCR) with the oligonucleotide probe as one of the two PCR primers. RT-PCR was not substantially more sensitive than DOP-hybridization assay. This procedure also was applicable to coconut cadang-cadang viroid (CCCVd), and oligonucleotide probes designed to be specific for either CTiVd or CCCVd distinguished between these two viroids in coconut leaf extracts. This strategy provides a rapid and specific indexing procedure for the two characterized viroids of coconut palm and will be applicable to further studies on the viroid-like sequences previously reported in tropical monocotyledons. PMID:18944882

  14. RADIAL VELOCITIES FROM VLT-KMOS SPECTRA OF GIANT STARS IN THE GLOBULAR CLUSTER NGC 6388

    SciTech Connect

    Lapenna, E.; Mucciarelli, A.; Lanzoni, B.; Ferraro, F. R.; Dalessandro, E.; Valenti, E.; Cirasuolo, M.

    2015-01-01

    We present new radial velocity measurements for 82 stars, members of the Galactic globular cluster (GC) NGC 6388, obtained from ESO-VLT K-band Multi Object Spectrograph (KMOS) spectra acquired during the instrument Science Verification. The accuracy of the wavelength calibration is discussed and a number of tests of the KMOS response are presented. The cluster systemic velocity obtained (81.3 ± 1.5 km s{sup –1}) is in very good agreement with previous determinations. While a hint of ordered rotation is found between 9'' and 20'' from the cluster center, where the distribution of radial velocities is clearly bimodal, more data are needed before drawing any firm conclusions. The acquired sample of radial velocities has also been used to determine the cluster velocity dispersion (VD) profile between ∼9'' and 70'', supplementing previous measurements at r < 2'' and r > 60'' obtained with ESO-SINFONI and ESO-FLAMES spectroscopy, respectively. The new portion of the VD profile nicely matches the previous ones, better defining the knee of the distribution. The present work clearly shows the effectiveness of a deployable integral field unit in measuring the radial velocities of individual stars for determining the VD profile of Galactic GCs. It represents the pilot project for an ongoing large program with KMOS and FLAMES at the ESO-VLT, aimed at determining the next generation of VD and rotation profiles for a representative sample of GCs.

  15. Assessment of the PW86+PBE+XDM density functional on van der Waals complexes at non-equilibrium geometries.

    PubMed

    Arabi, Alya A; Becke, Axel D

    2012-07-01

    The deficiency of conventional density-functional theory (DFT) in properly describing van der Waals (vdW) (especially dispersion-bound) complexes has been extensively addressed in the past decade. There are now several new methods published in the literature that are capable of accurately capturing weak dispersion interactions in complexes at equilibrium geometries. However, the performance of these new methods at non-equilibrium geometries remains to be assessed. We have previously published [F. O. Kannemann and A. D. Becke, J. Chem. Theory Comput. 6, 1081 (2010); A. D. Becke, A. A. Arabi, and F. O. Kannemann, Can. J. Chem. 88, 1057 (2010)] that the functional PW86+PBE+XDM for exchange + correlation + dispersion, respectively, is a highly accurate functional for general thermochemistry and vdW complexes at equilibrium geometries. Here, we show that this nonempirical, except for two parameters in the dispersion damping part, functional also performs well for vdW complexes at compressed and stretched intermonomer separations. The mean absolute relative error (MARE) is 9.4% overall for vdW complexes in the "S22×5" database incorporating compressed and stretched geometries [J. Rezac, K. E. Riley, and P. Hobza, J. Chem. Theory Comput. 7, 2427 (2011)]. Our largest MARE on the S22×5 database is 13.3% on the compressed geometry set.

  16. Binding of polycyclic aromatic hydrocarbons and graphene dimers in density functional theory

    NASA Astrophysics Data System (ADS)

    Chakarova-Käck, Svetla D.; Vojvodic, Aleksandra; Kleis, Jesper; Hyldgaard, Per; Schröder, Elsebeth

    2010-01-01

    An early van der Waals density functional (vdW-DF) described layered systems (such as graphite and graphene dimers) using a layer-averaged electron density in the evaluation of nonlocal correlations. This early vdW-DF version was also adapted to approximate the binding of polycyclic aromatic hydrocarbons (PAHs) (Chakarova S D and Schröder E 2005 J. Chem. Phys. 122 054102). In parallel to that PAH study, a new vdW-DF version (Dion M, Rydberg H, Schröder E, Langreth D C and Lundqvist B I 2004 Phys. Rev. Lett. 92 246401) was developed that provides accounts of nonlocal correlations for systems of general geometry. We apply here the latter vdW-DF version to aromatic dimers of benzene, naphthalene, anthracene and pyrene, stacked in sandwich (AA) structure, and the slipped-parallel (AB) naphthalene dimer. We further compare the results of the two methods as well as other theoretical results obtained by quantum-chemistry methods. We also compare calculations for two interacting graphene sheets in the AA and the AB structures and provide the corresponding graphene-from-graphite exfoliation energies. Finally, we present an overview of the scaling of the molecular-dimer interaction with the number of carbon atoms and with the number of carbon rings.

  17. Prediction of physicochemical properties of organic molecules using van der Waals surface electrostatic potentials.

    PubMed

    Kim, Chan Kyung; Lee, Kyung A; Hyun, Kwan Hoon; Park, Heung Jin; Kwack, In Young; Kim, Chang Kon; Lee, Hai Whang; Lee, Bon-Su

    2004-12-01

    The generalized interaction properties function (GIPF) methodology developed by Politzer and coworkers, which calculated molecular surface electrostatic potential (MSESP) on a density envelope surface, was modified by calculating the MSESP on a much simpler van der Waals (vdW) surface of a molecule. In this work, vdW molecular surfaces were obtained from the fully optimized structures confirmed by frequency calculations at B3LYP/6-31G(d) level of theory. Multiple linear regressions for normal boiling point, heats of vaporization, heats of sublimation, heats of fusion, liquid density, and solid density were performed using GIPF variables from vdW model surface. Results from our model are compared with those from Politzer and coworkers. The surface-dependent beta (and gamma) values are dependent on the surface models but the surface-independent alpha and regression coefficients (r) are constant when vdW surface and density surface with 0.001 a.u. contour value are compared. This interesting phenomenon is explained by linear dependencies of GIPF variables.

  18. Assessment of the PW86+PBE+XDM density functional on van der Waals complexes at non-equilibrium geometries

    NASA Astrophysics Data System (ADS)

    Arabi, Alya A.; Becke, Axel D.

    2012-07-01

    The deficiency of conventional density-functional theory (DFT) in properly describing van der Waals (vdW) (especially dispersion-bound) complexes has been extensively addressed in the past decade. There are now several new methods published in the literature that are capable of accurately capturing weak dispersion interactions in complexes at equilibrium geometries. However, the performance of these new methods at non-equilibrium geometries remains to be assessed. We have previously published [F. O. Kannemann and A. D. Becke, J. Chem. Theory Comput. 6, 1081 (2010), 10.1021/ct900699r; A. D. Becke, A. A. Arabi, and F. O. Kannemann, Can. J. Chem. 88, 1057 (2010), 10.1139/V10-073] that the functional PW86+PBE+XDM for exchange + correlation + dispersion, respectively, is a highly accurate functional for general thermochemistry and vdW complexes at equilibrium geometries. Here, we show that this nonempirical, except for two parameters in the dispersion damping part, functional also performs well for vdW complexes at compressed and stretched intermonomer separations. The mean absolute relative error (MARE) is 9.4% overall for vdW complexes in the "S22×5" database incorporating compressed and stretched geometries [J. Rezac, K. E. Riley, and P. Hobza, J. Chem. Theory Comput. 7, 2427 (2011), 10.1021/ct2002946]. Our largest MARE on the S22×5 database is 13.3% on the compressed geometry set.

  19. Global analytical ab initio ground-state potential energy surface for the C((1)D)+H2 reactive system.

    PubMed

    Zhang, Chunfang; Fu, Mingkai; Shen, Zhitao; Ma, Haitao; Bian, Wensheng

    2014-06-21

    A new global ab initio potential energy surface (called ZMB-a) for the 1(1)A' state of the C((1)D)+H2 reactive system has been constructed. This is based upon ab initio calculations using the internally contracted multireference configuration interaction approach with the aug-cc-pVQZ basis set, performed at about 6300 symmetry unique geometries. Accurate analytical fits are generated using many-body expansions with the permutationally invariant polynomials, except that the fit of the deep well region is taken from our previous fit. The ZMB-a surface is unique in the accurate description of the regions around conical intersections (CIs) and of van der Waals (vdW) interactions. The CIs between the 1(1)A' and 2(1)A' states cause two kinds of barriers on the ZMB-a surface: one is in the linear H-CH dissociation direction with a barrier height of 9.07 kcal/mol, which is much higher than those on the surfaces reported before; the other is in the C((1)D) collinearly attacking H2 direction with a barrier height of 12.39 kcal/mol. The ZMB-a surface basically reproduces our ab initio calculations in the vdW interaction regions, and supports a linear C-HH vdW complex in the entrance channel, and two vdW complexes in the exit channel, at linear CH-H and HC-H geometries, respectively.

  20. Density-functional description of polymer crystals: A comparative study of recent van der Waals functionals.

    PubMed

    Pham, Thinh H; Ramprasad, Rampi; Nguyen, Huy-Viet

    2016-06-01

    Due to the lack of treatment of long-range dispersion energies, density functional theory with local and semilocal approximations of exchange-correlation energy is known to fail in describing van der Waals complexes, including polymer crystals. This limitation can be overcome by using a different class of functionals, called van der Waals density functional (vdW-DF), originally developed by Dion et al. [Phys. Rev. Lett. 92, 246401 (2004)]. In this work, we performed a systematic study of structural properties of polymeric crystals using the original vdW-DF functional by Dion et al. and its variants and refinements. Our study shows that this class of functional outperforms the conventional LDA or PBE functionals and gives results with similar accuracy to that of empirical dispersion-corrected schemes such as DFT-D. This study suggests the use of vdW-DF2 functional - a revised version of vdW-DF functional - to obtain a high-fidelity prediction of structural and other properties of polymeric materials.

  1. On the anisotropy of van der Waals atomic radii of O, S, Se, F, Cl, Br, and I.

    PubMed

    Eramian, Hamed; Tian, Yong-Hui; Fox, Zach; Beneberu, Habtamu Z; Kertesz, Miklos

    2013-12-27

    The Cambridge Structural Database (CSD) was used to obtain flattening factors to describe the overall anisotropy of nonbonding van der Waals (vdW) contacts between several main group elements. The method for obtaining the flattening factors is based on a novel minimization process. Results show that the vdW contact distances are significantly dependent on the environment and the orientations of the surrounding covalently bonded atoms: head-on vdW contacts are generally shorter than sideways contacts in overall agreement with earlier results by Nyburg and Faerman (Acta Crystallogr., Sect. B: Struct. Sci. 1985, 41, 274-279). With the exception of Se, we find flattening factors that are somewhat smaller than those found earlier. High-level ab initio quantum chemical calculations using Ar and Ne as a probe also confirm the flattening effect and its dependency on the environment. A dozen popular long-range corrected and dispersion supplemented density functionals are compared with the CCSD(T) data. While several of them perform quite poorly, four DFT-D methods, especially B3LYP-GD3BJ, provided vdW flattening similar to those found by the CCSD(T) theory and experiment.

  2. Ice phases under ambient and high pressure: Insights from density functional theory

    NASA Astrophysics Data System (ADS)

    Fang, Yuan; Xiao, Bing; Tao, Jianmin; Sun, Jianwei; Perdew, John P.

    2013-06-01

    Water is common and plays a crucial role in biological, chemical, and physical processes, but its crystalline or ice state has a complicated structure. In this work, we study the lattice mismatch challenge for ice nucleation on silver iodide, the sublimation energy for different ice phases, and the structural phase-transition pressures of ice, with various density functionals. Our calculations show that the recently developed meta-generalized gradient approximation made simple (MGGA_MS) yields a lattice mismatch (3%) of hexagonal ice (ice Ih) with β-AgI in good agreement with experiment (2%), significantly better than the Perdew-Burke-Ernzerhof (PBE) GGA mismatch (6%). MGGA_MS is a computationally efficient semilocal functional that incorporates intermediate-range van der Waals (vdW) interaction, which, overall, performs well for ice and may be expected to improve upon PBE for liquid water. While MGGA_MS predicts the most realistic volumes and volume changes in the phase transitions of ice Ih to trigonal ice (ice II) and tetragonal ice (ice VIII), a more accurate description of some other properties of the higher-pressure phases (ice II and ice VIII) is provided by some functionals that include long-range vdW corrections (e.g., revised Tao-Perdew-Staroverov-Scuseria+vdW for sublimation energy and optB88-vdW for transition pressure).

  3. SCAN+rVV10: A promising van der Waals density functional

    NASA Astrophysics Data System (ADS)

    Peng, Haowei; Yang, Zeng-Hui; Sun, Jianwei; Perdew, John

    The newly developed ``strongly constrained and appropriately normed'' (SCAN) meta-generalized-gradient approximation (meta-GGA) can generally improve over the non-empirical Perdew-Burke-Ernzerhof (PBE) GGA not only for strong chemical bonding, but also for the intermediate-range van der Waals (vdW) interaction. However, the long-range vdW interaction is still missing. To remedy this, we propose here pairing SCAN with the non-local correlation part from the rVV10 vdW density functional, with only two empirical parameters. The resulting SCAN+rVV10 yields excellent geometric and energetic results not only for molecular systems, but also for solids and layered-structure materials, as well as the adsorption of benzene on coinage metal surfaces. Especially, SCAN+rVV10 outperforms all current methods with comparable computational efficiencies, accurately reproducing the three most fundamental parameters--the inter-layer binding energies, inter-, and intra-layer lattice constants--for 28 layered-structure materials. Hence, we have achieved with SCAN+rVV10 a promising vdW density functional for general geometries, with minimal empiricism. This work was supported as part of the Center for the Computational Design of Functional Layered Materials, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award #.DE-SC0012575.

  4. Prevalence and characterization of Chlamydia DNA in zoo animals in Japan.

    PubMed

    Kabeya, Hidenori; Sato, Shingo; Maruyama, Soichi

    2015-09-01

    Because many people visit zoos, prevention of zoonoses is important from the standpoint of public health. This study examined the prevalence of Chlamydia among zoo animals in Japan by PCR and characterized these bacteria by performing phylogenetic analyses of the sequences of the variable domain (VD) 2 and VD4 regions of the ompA gene, which encodes the Chlamydia major outer membrane protein. Fecal samples were collected from 1150 zoo animals in five zoos and examined for Chlamydia DNA. Chlamydia psittaci DNA was found in 3.9% of mammals, 7.2% of birds and 8.1% of reptiles. The prevalence of Chlamydia pneumoniae DNA was significantly higher in reptiles (5.8%) than in mammals (0.3%) and birds (0.3%). Phylogenetic analysis of the ompA VD2 region from 18 samples showed that nine were in three different clusters containing C. psittaci strains, six were in a cluster containing C. pneumoniae strains and three each formed a distinct branch. Furthermore, phylogenetic analysis of the ompA VD4 region showed that C. pneumoniae DNAs from reptiles were close to those from human patients. The C. pneumoniae DNAs from the European glass lizard, Emerald tree boa, and Panther chameleon were classified in clusters that were distinct from other strains, suggesting that these reptiles had each been infected with a specific C. pneumoniae genotype. This study showed that diverse Chlamydia strains have been prevalent among a variety of zoo animals.

  5. Esaki Diodes in van der Waals Heterojunctions with Broken-Gap Energy Band Alignment.

    PubMed

    Yan, Rusen; Fathipour, Sara; Han, Yimo; Song, Bo; Xiao, Shudong; Li, Mingda; Ma, Nan; Protasenko, Vladimir; Muller, David A; Jena, Debdeep; Xing, Huili Grace

    2015-09-01

    van der Waals (vdW) heterojunctions composed of two-dimensional (2D) layered materials are emerging as a solid-state materials family that exhibits novel physics phenomena that can power a range of electronic and photonic applications. Here, we present the first demonstration of an important building block in vdW solids: room temperature Esaki tunnel diodes. The Esaki diodes were realized in vdW heterostructures made of black phosphorus (BP) and tin diselenide (SnSe2), two layered semiconductors that possess a broken-gap energy band offset. The presence of a thin insulating barrier between BP and SnSe2 enabled the observation of a prominent negative differential resistance (NDR) region in the forward-bias current-voltage characteristics, with a peak to valley ratio of 1.8 at 300 K and 2.8 at 80 K. A weak temperature dependence of the NDR indicates electron tunneling being the dominant transport mechanism, and a theoretical model shows excellent agreement with the experimental results. Furthermore, the broken-gap band alignment is confirmed by the junction photoresponse, and the phosphorus double planes in a single layer of BP are resolved in transmission electron microscopy (TEM) for the first time. Our results represent a significant advance in the fundamental understanding of vdW heterojunctions and broaden the potential applications of 2D layered materials.

  6. Amplification of terahertz frequency acoustic phonons by drifting electrons in three-dimensional Dirac semimetals

    NASA Astrophysics Data System (ADS)

    Bhargavi, K. S.; Kubakaddi, S. S.

    2016-09-01

    The amplification coefficient α of acoustic phonons is theoretically investigated in a three-dimensional Dirac semimetal (3DDS) driven by a dc electric field E causing the drift of the electrons. It is numerically studied as a function of the frequency ωq, drift velocity vd, electron concentration ne, and temperature T in the Dirac semimetal Cd3As2. We find that the amplification of acoustic phonons (α ˜ hundreds of cm-1) takes place when the electron drift velocity vd is greater than the sound velocity vs. The amplification is found to occur at small E (˜few V/cm) due to large electron mobility. The frequency dependence of α shows amplification in the THz regime with a maximum αm occurring at the same frequency ωqm for different vd. The αm is found to increase with increasing vd. α vs ωq for different ne also shows a maximum, with αm shifting to higher ωq for larger ne. Each maximum is followed by a vanishing α at nearly "2kf cutoff," where kf is the Fermi wave vector. It is found that αm/ne and ωqm/ne1/3 are nearly constant. The αm ˜ ne can be used to identify the 3DDS phase as it differs from αm ˜ ne1/3 dependence in conventional bulk Cd3As2 semiconductor.

  7. Improving photoprotection attitudes in the tropics: sunburn vs vitamin D.

    PubMed

    Silva, Abel A

    2014-01-01

    The ultraviolet radiation of type B (the UVB) stimulates both the production of vitamin D (VD) and the incorporation of erythema dose (ED). The UVA also contributes to ED. The turning point between the benefit of producing VD and the harm of incorporating ED cannot be determined easily. However, the casual behavior regarding the exposure to the Sun can be changed in order to improve the protoprotection attitudes and create a trend towards benefit. In the case, people living in the low latitudes should exposure themselves to the Sun for a determined time interval within the noon time and avoid the Sun in other periods. This would produce an adequate amount of VD through the VD dose (207-214 J m(-2)) against minimum ED (≈105 J m(-2)) for skin type II. For it, unprotected forearms and hands must be exposed to the noon Sun (cloudless) for 11 min (winter) and 5 min (summer). The exposure at other times different from noon can represent increases of up to 24% in ED and up to 12 times in the time interval to be in the Sun in relation to the minimum amounts of both ED and time interval at noon.

  8. 14 CFR 23.443 - Gust loads.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Gust loads. (a) Vertical surfaces must be designed to withstand, in unaccelerated flight at speed V C... unaccelerated flight at VB, VC, VD, and VF. The derived gusts and airplane speeds corresponding to these...=Derived gust velocity (f.p.s.); ρ=Air density (slugs/cu.ft.); W=the applicable weight of the airplane...

  9. 14 CFR 23.443 - Gust loads.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Gust loads. (a) Vertical surfaces must be designed to withstand, in unaccelerated flight at speed V C... unaccelerated flight at VB, VC, VD, and VF. The derived gusts and airplane speeds corresponding to these...=Derived gust velocity (f.p.s.); ρ=Air density (slugs/cu.ft.); W=the applicable weight of the airplane...

  10. Rings sliding on a honeycomb network: Adsorption contours, interactions, and assembly of benzene on Cu(111)

    NASA Astrophysics Data System (ADS)

    Berland, K.; Einstein, T. L.; Hyldgaard, P.

    2009-10-01

    Using a van der Waals density functional (vdW-DF) [Phys. Rev. Lett. 92, 246401 (2004)], we perform ab initio calculations for the adsorption energy of benzene (Bz) on Cu(111) as a function of lateral position and height. We find that the vdW-DF inclusion of nonlocal correlations (responsible for dispersive interactions) changes the relative stability of eight binding-position options and increases the binding energy by over an order of magnitude, achieving good agreement with experiment. The admolecules can move almost freely along a honeycomb web of “corridors” passing between fcc and hcp hollow sites via bridge sites. Our diffusion barriers (for dilute and two condensed adsorbate phases) are consistent with experimental observations. Further vdW-DF calculations suggest that the more compact (hexagonal) Bz-overlayer phase, with lattice constant a=6.74Å , is due to direct Bz-Bz vdW attraction, which extends to ˜8Å . We attribute the second, sparser hexagonal Bz phase, with a=10.24Å , to indirect electronic interactions mediated by the metallic surface state on Cu(111). To support this claim, we use a formal Harris-functional approach to evaluate nonperturbationally the asymptotic form of this indirect interaction. Thus, we can account well for benzene self-organization on Cu(111).

  11. Diffuse-interface modeling of liquid-vapor coexistence in equilibrium drops using smoothed particle hydrodynamics.

    PubMed

    Sigalotti, Leonardo Di G; Troconis, Jorge; Sira, Eloy; Peña-Polo, Franklin; Klapp, Jaime

    2014-07-01

    We study numerically liquid-vapor phase separation in two-dimensional, nonisothermal, van der Waals (vdW) liquid drops using the method of smoothed particle hydrodynamics (SPH). In contrast to previous SPH simulations of drop formation, our approach is fully adaptive and follows the diffuse-interface model for a single-component fluid, where a reversible, capillary (Korteweg) force is added to the equations of motion to model the rapid but smooth transition of physical quantities through the interface separating the bulk phases. Surface tension arises naturally from the cohesive part of the vdW equation of state and the capillary forces. The drop models all start from a square-shaped liquid and spinodal decomposition is investigated for a range of initial densities and temperatures. The simulations predict the formation of stable, subcritical liquid drops with a vapor atmosphere, with the densities and temperatures of coexisting liquid and vapor in the vdW phase diagram closely matching the binodal curve. We find that the values of surface tension, as determined from the Young-Laplace equation, are in good agreement with the results of independent numerical simulations and experimental data. The models also predict the increase of the vapor pressure with temperature and the fitting to the numerical data reproduces very well the Clausius-Clapeyron relation, thus allowing for the calculation of the vaporization pressure for this vdW fluid.

  12. Interlayer electronic hybridization leads to exceptional thickness-dependent vibrational properties in few-layer black phosphorus.

    PubMed

    Hu, Zhi-Xin; Kong, Xianghua; Qiao, Jingsi; Normand, Bruce; Ji, Wei

    2016-02-01

    Stacking two-dimensional (2D) materials into multi-layers or heterostructures, known as van der Waals (vdW) epitaxy, is an essential degree of freedom for tuning their properties on demand. Few-layer black phosphorus (FLBP), a material with high potential for nano- and optoelectronics applications, appears to have interlayer couplings much stronger than graphene and other 2D systems. Indeed, these couplings call into question whether the stacking of FLBP can be governed only by vdW interactions, which is of crucial importance for epitaxy and property refinement. Here, we perform a theoretical investigation of the vibrational properties of FLBP, which reflect directly its interlayer coupling, by discussing six Raman-observable phonons, including three optical, one breathing and two shear modes. With increasing sample thickness, we find anomalous redshifts of the frequencies for each optical mode but a blueshift for the armchair shear mode. Our calculations also show splitting of the phonon branches, due to anomalous surface phenomena, and strong phonon-phonon coupling. By computing uniaxial stress effects, inter-atomic force constants and electron densities, we provide a compelling demonstration that these properties are the consequence of strong and highly directional interlayer interactions arising from the electronic hybridization of the lone electron-pairs of FLBP, rather than from vdW interactions. This exceptional interlayer coupling mechanism controls the stacking stability of BP layers and thus opens a new avenue beyond vdW epitaxy for understanding the design of 2D heterostructures.

  13. 25-Hydroxyvitamin D3-deficiency enhances oxidative stress and corticosteroid resistance in severe asthma exacerbation.

    PubMed

    Lan, Nan; Luo, Guangyan; Yang, Xiaoqiong; Cheng, Yuanyuan; Zhang, Yun; Wang, Xiaoyun; Wang, Xing; Xie, Tao; Li, Guoping; Liu, Zhigang; Zhong, Nanshan

    2014-01-01

    Oxidative stress plays a significant role in exacerbation of asthma. The role of vitamin D in oxidative stress and asthma exacerbation remains unclear. We aimed to determine the relationship between vitamin D status and oxidative stress in asthma exacerbation. Severe asthma exacerbation patients with 25-hydroxyvitamin D3-deficiency (V-D deficiency) or 25-hydroxyvitamin D-sufficiency (V-D sufficiency) were enrolled. Severe asthma exacerbation with V-D-deficiency showed lower forced expiratory volume in one second (FEV1) compared to that with V-D-sufficiency. V-D-deficiency intensified ROS release and DNA damage and increased TNF-α, OGG1 and NFκB expression and NFκB phosphorylation in severe asthma exacerbation. Supplemental vitamin D3 significantly increased the rates of FEV1 change and decreased ROS and DNA damage in V-D-deficiency. Vitamin D3 inhibited LPS-induced ROS and DNA damage and were associated with a decline in TNF-α and NFκB in epithelial cells. H2O2 reduces nuclear translocation of glucocorticoid receptors in airway epithelial cell lines. V-D pretreatment enhanced the dexamethasone-induced nuclear translocation of glucocorticoid receptors in airway epithelial cell lines and monocytes from 25-hydroxyvitamin D3-deficiency asthma patients. These findings indicate that V-D deficiency aggravates oxidative stress and DNA damage, suggesting a possible mechanism for corticosteroid resistance in severe asthma exacerbation.

  14. Oxidative stress-elevated high gamma glutamyl transferase levels, and aging, intake of tropical food plants, migration and visual disability in Central Africans

    PubMed Central

    Longo-Mbenza, Benjamin; Muaka, Moïse Mvitu; Mokondjimobe, Etienne; Ndembe, Dalida Kibokela; Mona, Doris Tulomba; Buassabu-bu-Tsumbu, Baudouin

    2012-01-01

    AIM To investigate the independent pathogenic role of high serum gamma-glutamyl transferase (GGT) levels, sociodemographic data, dietary and environmental risk factors for visual disability (VD). METHODS This was a case-control study, run in 200 black Congolese patients managed in Saint Joseph Hospital Ophthalmology Division from Kinshasa town. Logistic regression model was used to identify determinants of VD (n=58) among sex, age, cigarette smoking, alcohol abuse, rural-urban migration, education levels, aging ≥60 years, intake of red Beans, Safou fruit and Taro leaves, lipid profile, residence, socioeconomic status, and GGT. RESULTS After adjusting for confounding factors, we identified migration (OR=3.7 95% CI: 1.2-11.3; P=0.023), low education level (OR=3.1 95% CI 1.1-8.5; P=0.026), no intake of Safou fruit (OR=34.2 95% CI 11.5-102; P<0.0001), age ≥ 60 years (OR=2.5 95% CI 1.01-6.5; P=0.049), and serum GGT ≥10 U/L (OR=3.6 95% CI 1.3-9.6; P=0.012) as the significant and independent determinants of VD. CONCLUSION VD appears as a major public health problem in Central Africa to be prevented or delayed by control of migration, lifestyle changes, antioxidant supplements, appropriate diet, nutrition education, and blocking of oxidative stress. PMID:22937512

  15. Intrapartum Cervical Laceration and Subsequent Pregnancy Outcomes

    PubMed Central

    Wong, Luchin F.; Wilkes, Jacob; Korgenski, Kent; Varner, Michael W.; Manuck, Tracy A.

    2016-01-01

    Objective  The objective of this study was to describe pregnancy outcomes, including cervical insufficiency and preterm birth, in the subsequent pregnancy following an intrapartum cervical laceration. Study Design  Retrospective cohort of women with their first two consecutive singleton pregnancies carried to ≥ 200/7 weeks' gestation within a tertiary health care system from 2002 to 2012. Cervical laceration cases were identified by ICD9 codes and included if suture repair was required. Results  In this study, 55 women were confirmed to have a cervical laceration in the first delivery; 43 lacerations after vaginal delivery (VD) and 12 after cesarean delivery (CD). The median gestational age of the first delivery was 400/7 weeks and the median birth weight 3,545 g; these did not differ between VD and CD. In the second pregnancy, 2 of 55 women (4.6%) had a prophylactic cerclage placed; 1 carried to term and the other delivered at 356/7 weeks. In total, four women (9.3%) delivered the second pregnancy < 37 weeks: three had a prior term VD and one had a prior 34 weeks VD. There was only one case of recurrent cervical laceration, occurring in the setting of vaginal deliveries. Conclusion  Obstetric cervical lacerations are uncommon. Complications in the following pregnancy were low, despite lack of additional prophylactic cerclage use. PMID:27621953

  16. van der Waals density functionals built upon the electron-gas tradition: facing the challenge of competing interactions.

    PubMed

    Berland, Kristian; Arter, Calvin A; Cooper, Valentino R; Lee, Kyuho; Lundqvist, Bengt I; Schröder, Elsebeth; Thonhauser, T; Hyldgaard, Per

    2014-05-14

    The theoretical description of sparse matter attracts much interest, in particular for those ground-state properties that can be described by density functional theory. One proposed approach, the van der Waals density functional (vdW-DF) method, rests on strong physical foundations and offers simple yet accurate and robust functionals. A very recent functional within this method called vdW-DF-cx [K. Berland and P. Hyldgaard, Phys. Rev. B 89, 035412 (2014)] stands out in its attempt to use an exchange energy derived from the same plasmon-based theory from which the nonlocal correlation energy was derived. Encouraged by its good performance for solids, layered materials, and aromatic molecules, we apply it to several systems that are characterized by competing interactions. These include the ferroelectric response in PbTiO3, the adsorption of small molecules within metal-organic frameworks, the graphite/diamond phase transition, and the adsorption of an aromatic-molecule on the Ag(111) surface. Our results indicate that vdW-DF-cx is overall well suited to tackle these challenging systems. In addition to being a competitive density functional for sparse matter, the vdW-DF-cx construction presents a more robust general-purpose functional that could be applied to a range of materials problems with a variety of competing interactions.

  17. Thickness dependence of surface energy and contact angle of water droplets on ultrathin MoS2 films.

    PubMed

    Guo, Yanhua; Wang, Zhengfei; Zhang, Lizhi; Shen, Xiaodong; Liu, Feng

    2016-06-01

    We have performed a systematic density functional study of surface energy of MoS2 films as a function of thickness from one to twelve layers with the consideration of van der Waals (vdW) interactions using the vdW-DF and DFT-D2 methods. Both vdW schemes show that the surface energy will increase with the increase of the number of atomic layers and converge to a constant value at about six layers. Based on the calculated surface energies, we further analyze the surface contact angle of water droplets on the MoS2 film surface using Young's equation as a function of thickness in comparison with experiments, from which the water-MoS2 interfacial energy is derived to be independent of MoS2 thickness. Our calculations indicate that the vdW interactions between the MoS2 layers play an important role in determining surface energy, and results in the thickness dependence of the contact angle of water droplets on the MoS2 film surface. Our results explain well the recent wetting experiment [Nano Lett., 2014, 14(8), 4314], and will be useful for future studies of physical and chemical properties of ultrathin MoS2 films. PMID:27173479

  18. Fluorinated graphene and hexagonal boron nitride as ALD seed layers for graphene-based van der Waals heterostructures.

    PubMed

    Guo, Hongwei; Liu, Yunlong; Xu, Yang; Meng, Nan; Wang, Hongtao; Hasan, Tawfique; Wang, Xinran; Luo, Jikui; Yu, Bin

    2014-09-01

    Ultrathin dielectric materials prepared by atomic-layer-deposition (ALD) technology are commonly used in graphene electronics. Using the first-principles density functional theory calculations with van der Waals (vdW) interactions included, we demonstrate that single-side fluorinated graphene (SFG) and hexagonal boron nitride (h-BN) exhibit large physical adsorption energy and strong electrostatic interactions with H2O-based ALD precursors, indicating their potential as the ALD seed layer for dielectric growth on graphene. In graphene-SFG vdW heterostructures, graphene is n-doped after ALD precursor adsorption on the SFG surface caused by vertical intrinsic polarization of SFG. However, graphene-h-BN vdW heterostructures help preserving the intrinsic characteristics of the underlying graphene due to in-plane intrinsic polarization of h-BN. By choosing SFG or BN as the ALD seed layer on the basis of actual device design needs, the graphene vdW heterostructures may find applications in low-dimensional electronics.

  19. Effect of chia seed meal on baking quality of cakes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chia seed is a good source of dietary fiber and complete proteins; chia seeds contain many health-promoting compounds and can be incorporated into baking goods for high-protein, high-fiber diet. Food grade chia seeds were obtained from a local grocery store and ground into meal using Retsch Model VD...

  20. Esaki Diodes in van der Waals Heterojunctions with Broken-Gap Energy Band Alignment.

    PubMed

    Yan, Rusen; Fathipour, Sara; Han, Yimo; Song, Bo; Xiao, Shudong; Li, Mingda; Ma, Nan; Protasenko, Vladimir; Muller, David A; Jena, Debdeep; Xing, Huili Grace

    2015-09-01

    van der Waals (vdW) heterojunctions composed of two-dimensional (2D) layered materials are emerging as a solid-state materials family that exhibits novel physics phenomena that can power a range of electronic and photonic applications. Here, we present the first demonstration of an important building block in vdW solids: room temperature Esaki tunnel diodes. The Esaki diodes were realized in vdW heterostructures made of black phosphorus (BP) and tin diselenide (SnSe2), two layered semiconductors that possess a broken-gap energy band offset. The presence of a thin insulating barrier between BP and SnSe2 enabled the observation of a prominent negative differential resistance (NDR) region in the forward-bias current-voltage characteristics, with a peak to valley ratio of 1.8 at 300 K and 2.8 at 80 K. A weak temperature dependence of the NDR indicates electron tunneling being the dominant transport mechanism, and a theoretical model shows excellent agreement with the experimental results. Furthermore, the broken-gap band alignment is confirmed by the junction photoresponse, and the phosphorus double planes in a single layer of BP are resolved in transmission electron microscopy (TEM) for the first time. Our results represent a significant advance in the fundamental understanding of vdW heterojunctions and broaden the potential applications of 2D layered materials. PMID:26226296

  1. Accurate and Efficient Calculation of van der Waals Interactions Within Density Functional Theory by Local Atomic Potential Approach

    SciTech Connect

    Sun, Y. Y.; Kim, Y. H.; Lee, K.; Zhang, S. B.

    2008-01-01

    Density functional theory (DFT) in the commonly used local density or generalized gradient approximation fails to describe van der Waals (vdW) interactions that are vital to organic, biological, and other molecular systems. Here, we propose a simple, efficient, yet accurate local atomic potential (LAP) approach, named DFT+LAP, for including vdW interactions in the framework of DFT. The LAPs for H, C, N, and O are generated by fitting the DFT+LAP potential energy curves of small molecule dimers to those obtained from coupled cluster calculations with single, double, and perturbatively treated triple excitations, CCSD(T). Excellent transferability of the LAPs is demonstrated by remarkable agreement with the JSCH-2005 benchmark database [P. Jurecka et al. Phys. Chem. Chem. Phys. 8, 1985 (2006)], which provides the interaction energies of CCSD(T) quality for 165 vdW and hydrogen-bonded complexes. For over 100 vdW dominant complexes in this database, our DFT+LAP calculations give a mean absolute deviation from the benchmark results less than 0.5 kcal/mol. The DFT+LAP approach involves no extra computational cost other than standard DFT calculations and no modification of existing DFT codes, which enables straightforward quantum simulations, such as ab initio molecular dynamics, on biomolecular systems, as well as on other organic systems.

  2. Differential diagnosis of 201 possible Creutzfeldt-Jakob disease patients.

    PubMed

    Van Everbroeck, Bart; Dobbeleir, Itte; De Waele, Michele; De Deyn, Peter; Martin, Jean-Jacques; Cras, Patrick

    2004-03-01

    Our objective was to describe the clinical signs of 'possible' Creutzfeldt-Jakob disease (CJD) and to investigate whether current diagnostic criteria can accurately differentiate between different forms of dementia. We studied clinical data of 'definite' CJD, Alzheimer's disease (AD), dementia with Lewy bodies (DLB), and vascular dementia (VD) patients. Two subgroups were used: the first consisted of patients with clinical signs compatible with 'possible' CJD but in whom another final diagnosis was made and a second group with a typical evolution of the respective dementia. More focal neurological deficits were observed in AD, DLB or VD patients initially classified as 'possible' CJD than in typical patients. A typical electroencephalogram showing periodic sharp wave complexes was observed in 26 (50%) CJD and 6% of other dementia patients. The 14-3-3 protein was detected in all CJD and 8% of other dementia patients. In patients with rapidly progressive dementia and focal neurological signs, CJD should be considered. When faced with the triad: dementia, myoclonus, and initial memory problems AD should be considered if the disease duration is longer than 1 year. The diagnosis of DLB is suggested, if Parkinsonism or fluctuations are present, whereas a focal onset and compatible brain imaging can indicate VD. Findings suggestive of CJD on EEG, brain imaging, and CSF do not exclude other dementias but make them very unlikely. These observations cannot only assist in the differential diagnosis of CJD but also with the identification of AD, DLB or VD patients with atypical clinical history.

  3. How van der Waals interactions determine the unique properties of water.

    PubMed

    Morawietz, Tobias; Singraber, Andreas; Dellago, Christoph; Behler, Jörg

    2016-07-26

    Whereas the interactions between water molecules are dominated by strongly directional hydrogen bonds (HBs), it was recently proposed that relatively weak, isotropic van der Waals (vdW) forces are essential for understanding the properties of liquid water and ice. This insight was derived from ab initio computer simulations, which provide an unbiased description of water at the atomic level and yield information on the underlying molecular forces. However, the high computational cost of such simulations prevents the systematic investigation of the influence of vdW forces on the thermodynamic anomalies of water. Here, we develop efficient ab initio-quality neural network potentials and use them to demonstrate that vdW interactions are crucial for the formation of water's density maximum and its negative volume of melting. Both phenomena can be explained by the flexibility of the HB network, which is the result of a delicate balance of weak vdW forces, causing, e.g., a pronounced expansion of the second solvation shell upon cooling that induces the density maximum.

  4. Electronic structures and enhanced optical properties of blue phosphorene/transition metal dichalcogenides van der Waals heterostructures

    PubMed Central

    Peng, Qiong; Wang, Zhenyu; Sa, Baisheng; Wu, Bo; Sun, Zhimei

    2016-01-01

    As a fast emerging topic, van der Waals (vdW) heterostructures have been proposed to modify two-dimensional layered materials with desired properties, thus greatly extending the applications of these materials. In this work, the stacking characteristics, electronic structures, band edge alignments, charge density distributions and optical properties of blue phosphorene/transition metal dichalcogenides (BlueP/TMDs) vdW heterostructures were systematically studied based on vdW corrected density functional theory. Interestingly, the valence band maximum and conduction band minimum are located in different parts of BlueP/MoSe2, BlueP/WS2 and BlueP/WSe2 heterostructures. The MoSe2, WS2 or WSe2 layer can be used as the electron donor and the BlueP layer can be used as the electron acceptor. We further found that the optical properties under visible-light irradiation of BlueP/TMDs vdW heterostructures are significantly improved. In particular, the predicted upper limit energy conversion efficiencies of BlueP/MoS2 and BlueP/MoSe2 heterostructures reach as large as 1.16% and 0.98%, respectively, suggesting their potential applications in efficient thin-film solar cells and optoelectronic devices. PMID:27553787

  5. Polymorphism and Elastic Response of Molecular Materials from First Principles: How Hard Can it Be?

    NASA Astrophysics Data System (ADS)

    Reilly, Anthony; Tkatchenko, Alexandre

    2014-03-01

    Molecular materials are of great fundamental and applied importance in science and industry, with numerous applications in pharmaceuticals, electronics, sensing, and catalysis. A key challenge for theory has been the prediction of their stability, polymorphism and response to perturbations. While pairwise models of van der Waals (vdW) interactions have improved the ability of density functional theory (DFT) to model these systems, substantial quantitative and even qualitative failures remain. In this contribution we show how a many-body description of vdW interactions can dramatically improve the accuracy of DFT for molecular materials, yielding quantitative description of stabilities and polymorphism for these challenging systems. Moreover, the role of many-body vdW interactions goes beyond stabilities to response properties. In particular, we have studied the elastic properties of a series of molecular crystals, finding that many-body vdW interactions can account for up to 30% of the elastic response, leading to quantitative and qualitative changes in elastic behavior. We will illustrate these crucial effects with the challenging case of the polymorphs of aspirin, leading to a better understanding of the conflicting experimental and theoretical studies of this system.

  6. VOLATILE ORGANO-METALLOIDS IN BIO-SOLID MATERIALS: ANALYSIS BY VACUUM DISTILLATION-GC/MS

    EPA Science Inventory

    An analytical method based on vacuum distillation-gas chromatography-mass spectrometry (VD-GC-MS)

    was developed for determining volatile organo-metalloid contaminants in bio-solid materials. Method

    performance was evaluated for dimethylselenide (DMSe), dimethyldisel...

  7. Estrogen has opposing effects on vascular reactivity in obese, insulin-resistant male Zucker rats

    NASA Technical Reports Server (NTRS)

    Brooks-Asplund, Esther M.; Shoukas, Artin A.; Kim, Soon-Yul; Burke, Sean A.; Berkowitz, Dan E.

    2002-01-01

    We hypothesized that estradiol treatment would improve vascular dysfunction commonly associated with obesity, hyperlipidemia, and insulin resistance. A sham operation or 17beta-estradiol pellet implantation was performed in male lean and obese Zucker rats. Maximal vasoconstriction (VC) to phenylephrine (PE) and potassium chloride was exaggerated in control obese rats compared with lean rats, but estradiol significantly attenuated VC in the obese rats. Estradiol reduced the PE EC50 in all groups. This effect was cyclooxygenase independent, because preincubation with indomethacin reduced VC response to PE similarly in a subset of control and estrogen-treated lean rats. Endothelium-independent vasodilation (VD) to sodium nitroprusside was similar among groups, but endothelium-dependent VD to ACh was significantly impaired in obese compared with lean rats. Estradiol improved VD in lean and obese rats by decreasing EC50 but impaired function by decreasing maximal VD. The shift in EC50 corresponded to an upregulation in nitric oxide synthase III protein expression in the aorta of the estrogen-treated obese rats. In summary, estrogen treatment improves vascular function in male insulin-resistant, obese rats, partially via an upregulation of nitric oxide synthase III protein expression. These effects are counteracted by adverse factors, such as hyperlipidemia and, potentially, a release of an endothelium-derived contractile agent.

  8. Elements of Vortex-Dipole Dynamics in a Nonuniform Bose-Einstein Condensate

    NASA Astrophysics Data System (ADS)

    Sakhel, Roger R.; Sakhel, Asaad R.

    2016-09-01

    The elements of the vortex-dipole (VD) dynamics are numerically examined in a nonuniform Bose-Einstein condensate (BEC) using the time-dependent Gross-Pitaevskii equation that is solved by the split-step Crank-Nicolson method in real time. The BEC is trapped in a harmonic potential, surrounded by a hard-wall box potential, and stirred by an attractive focusing laser. In this regard, we particularly refer to a recent examination by Aioi et al. (Phys. Rev. X, 1: 021003, 2011) who presented controlled VD generation using a red laser in an infinite homogeneous BEC for comparison. It is found that the dynamics in the present nonuniform BEC is quite different from the one reported earlier by Aioi et al. The elements considered are the phase maps that demonstrate the presence of phase rings, the effects of the coupling constant on the vortex lifetime, the density at the vortex core, and the heating effects of the stirrer. Upon a suitable choice of coupling for our system, a VD generated by the moving fragment is transferred to and trapped by the central BEC cloud. The latter serves as a dissipationless vortex respository, where the lifetime of the VD is extended on demand. An analytical model is presented that qualitatively reproduces the wavefunction with its principle features and provides details inaccessible by the present numerical method such as the coupling between stirrer and BEC.

  9. Improved First Pass Spiral Myocardial Perfusion Imaging with Variable Density Trajectories

    PubMed Central

    Salerno, Michael; Sica, Christopher; Kramer, Christopher M.; Meyer, Craig H.

    2013-01-01

    Purpose To develop and evaluate variable-density (VD) spiral first-pass perfusion pulse sequences for improved efficiency and off-resonance performance and to demonstrate the utility of an apodizing density compensation function (DCF) to improve SNR and reduce dark-rim artifact caused by cardiac motion and Gibbs Ringing. Methods Three variable density spiral trajectories were designed, simulated, and evaluated in 18 normal subjects, and in 8 patients with cardiac pathology on a 1.5T scanner. Results By utilizing a density compensation function (DCF) which intentionally apodizes the k-space data, the side-lobe amplitude of the theoretical PSF is reduced by 68%, with only a 13% increase in the FWHM of the main-lobe as compared to the same data corrected with a conventional VD DCF, and has an 8% higher resolution than a uniform density spiral with the same number of interleaves and readout duration. Furthermore, this strategy results in a greater than 60% increase in measured SNR as compared to the same VD spiral data corrected with a conventional DCF (p<0.01). Perfusion defects could be clearly visualized with minimal off-resonance and dark-rim artifacts. Conclusion VD spiral pulse sequences using an apodized DCF produce high-quality first-pass perfusion images with minimal dark-rim and off-resonance artifacts, high SNR and CNR and good delineation of resting perfusion abnormalities. PMID:23280884

  10. ANALYSES OF FISH TISSUE BY VACUUM DISTILLATION/GAS CHROMATOGRAPHY/MASS SPECTROMETRY

    EPA Science Inventory

    The analyses of fish tissue using VD/GC/MS with surrogate-based matrix corrections is described. Techniques for equilibrating surrogate and analyte spikes with a tissue matrix are presented, and equilibrated spiked samples are used to document method performance. The removal of a...

  11. Transposable elements in phytopathogenic Verticillium spp.: insights into genome evolution and inter- and intra-specific diversification

    PubMed Central

    2012-01-01

    Background Verticillium dahliae (Vd) and Verticillium albo-atrum (Va) are cosmopolitan soil fungi causing very disruptive vascular diseases on a wide range of crop plants. To date, no sexual stage has been identified in either microorganism suggesting that somatic mutation is a major force in generating genetic diversity. Whole genome comparative analysis of the recently sequenced strains VdLs.17 and VaMs.102 revealed that non-random insertions of transposable elements (TEs) have contributed to the generation of four lineage-specific (LS) regions in VdLs.17. Results We present here a detailed analysis of Class I retrotransposons and Class II “cut-and-paste” DNA elements detected in the sequenced Verticillium genomes. We report also of their distribution in other Vd and Va isolates from various geographic origins. In VdLs.17, we identified and characterized 56 complete retrotransposons of the Gypsy-, Copia- and LINE-like types, as well as 34 full-length elements of the “cut-and-paste” superfamilies Tc1/mariner, Activator and Mutator. While Copia and Tc1/mariner were present in multiple identical copies, Activator and Mutator sequences were highly divergent. Most elements comprised complete ORFs, had matching ESTs and showed active transcription in response to stress treatment. Noticeably, we found evidences of repeat-induced point mutation (RIP) only in some of the Gypsy retroelements. While Copia-, Gypsy- and Tc1/mariner-like transposons were prominent, a large variation in presence of the other types of mobile elements was detected in the other Verticillium spp. strains surveyed. In particular, neither complete nor defective “cut-and-paste” TEs were found in VaMs.102. Conclusions Copia-, Gypsy- and Tc1/mariner-like transposons are the most wide-spread TEs in the phytopathogens V. dahliae and V. albo-atrum. In VdLs.17, we identified several retroelements and “cut-and-paste” transposons still potentially active. Some of these elements have undergone

  12. The use of the SAEM algorithm in MONOLIX software for estimation of population pharmacokinetic-pharmacodynamic-viral dynamics parameters of maraviroc in asymptomatic HIV subjects.

    PubMed

    Chan, Phylinda L S; Jacqmin, Philippe; Lavielle, Marc; McFadyen, Lynn; Weatherley, Barry

    2011-02-01

    Using simulated viral load data for a given maraviroc monotherapy study design, the feasibility of different algorithms to perform parameter estimation for a pharmacokinetic-pharmacodynamic-viral dynamics (PKPD-VD) model was assessed. The assessed algorithms are the first-order conditional estimation method with interaction (FOCEI) implemented in NONMEM VI and the SAEM algorithm implemented in MONOLIX version 2.4. Simulated data were also used to test if an effect compartment and/or a lag time could be distinguished to describe an observed delay in onset of viral inhibition using SAEM. The preferred model was then used to describe the observed maraviroc monotherapy plasma concentration and viral load data using SAEM. In this last step, three modelling approaches were compared; (i) sequential PKPD-VD with fixed individual Empirical Bayesian Estimates (EBE) for PK, (ii) sequential PKPD-VD with fixed population PK parameters and including concentrations, and (iii) simultaneous PKPD-VD. Using FOCEI, many convergence problems (56%) were experienced with fitting the sequential PKPD-VD model to the simulated data. For the sequential modelling approach, SAEM (with default settings) took less time to generate population and individual estimates including diagnostics than with FOCEI without diagnostics. For the given maraviroc monotherapy sampling design, it was difficult to separate the viral dynamics system delay from a pharmacokinetic distributional delay or delay due to receptor binding and subsequent cellular signalling. The preferred model included a viral load lag time without inter-individual variability. Parameter estimates from the SAEM analysis of observed data were comparable among the three modelling approaches. For the sequential methods, computation time is approximately 25% less when fixing individual EBE of PK parameters with omission of the concentration data compared with fixed population PK parameters and retention of concentration data in the PD-VD

  13. Sub-Doppler Electronic Spectrum of the BENZENE-D2 Complex

    NASA Astrophysics Data System (ADS)

    Hayashi, Masato; Ohshima, Yasuhiro

    2014-06-01

    Excitation spectrum of the benzene-D2 van der Waals (vdW) complex in the vicinity of the S1 ← S0 601 vibronic transition of the monomer was recorded by utilizing mass-selective two-color resonance-enhanced two-photon ionization. Extensive adiabatic cooling with the rotational temperature of ěrb|<| 0.5 K was conducted by the high-pressure pulsed expansion, and sub-Doppler resolution yielding the line width of 250 MHz was realized in a collimated molecular beam by employing Fourier-transform-limited ultraviolet pulses for the excitation. In contrast to our previous study on the benzene-H2 complex, weaker binding ortho nuclear-spin isomer, correlating to the j = 0 state of a freely rotating D2, was observed in addition to the stronger binding para isomer (with j = 1), by using a gas sample of normal D2. Three and two vibronic bands involving vdW-mode excitation were observed for the para and ortho isomers, respectively. By comparing the present results with those of the benzene-H2 complex, we made unambiguous assignments on the vdW modes involved in each observed band, and obtained complete sets of vibrational frequencies of all the three vdW modes for the both H2 and D2 isotopomers in the S1 61 manifold. One of the vdW frequency correlates to the splitting between the m = 0 and ± 1 sublevels in the j = 1 state of a freely rotating H2/D2 molecule, and the potential barrier for the hindered internal rotation has been evaluated to be ca. 60 cm-1 from the values. Ratio of the vdW frequencies between the H2 and D2 species deviate significantly from the value for the harmonic vibration (i.e., √{2} ≈ 1.4), indicating substantial anharmonic character of the vdW modes in the complex. M. Hayashi and Y. Ohshima, Chem. Phys. 419, 131-137 (2013). M. Hayashi and Y. Ohshima, J. Phys. Chem. A 117, 9819-9830 (2013).

  14. Evaluation of a variable dose acquisition technique for microcalcification and mass detection in digital breast tomosynthesis

    SciTech Connect

    Das, Mini; Gifford, Howard C.; O'Connor, J. Michael; Glick, Stephen J.

    2009-06-15

    In this article the authors evaluate a recently proposed variable dose (VD)-digital breast tomosynthesis (DBT) acquisition technique in terms of the detection accuracy for breast masses and microcalcification (MC) clusters. With this technique, approximately half of the total dose is used for one center projection and the remaining dose is split among the other tomosynthesis projection views. This acquisition method would yield both a projection view and a reconstruction view. One of the aims of this study was to evaluate whether the center projection alone of the VD acquisition can provide equal or superior MC detection in comparison to the 3D images from uniform dose (UD)-DBT. Another aim was to compare the mass-detection capabilities of 3D reconstructions from VD-DBT and UD-DBT. In a localization receiver operating characteristic (LROC) observer study of MC detection, the authors compared the center projection of a VD acquisition scheme (at 2 mGy dose) with detector pixel size of 100 {mu}m with the UD-DBT reconstruction (at 4 mGy dose) obtained with a voxel size of 100 {mu}m. MCs with sizes of 150 and 180 {mu}m were used in the study, with each cluster consisting of seven MCs distributed randomly within a small volume. Reconstructed images in UD-DBT were obtained from a projection set that had a total of 4 mGy dose. The current study shows that for MC detection, using the center projection alone of VD acquisition scheme performs worse with area under the LROC curve (A{sub L}) of 0.76 than when using the 3D reconstructed image using the UD acquisition scheme (A{sub L}=0.84). A 2D ANOVA found a statistically significant difference (p=0.038) at a significance level of 0.05. In the current study, although a reconstructed image was also available using the VD acquisition scheme, it was not used to assist the MC detection task which was done using the center projection alone. In the case of evaluation of detection accuracy of masses, the reconstruction with VD-DBT (A

  15. Water use and quality of fresh surface-water resources in the Barataria-Terrebonne Basins, Louisiana

    USGS Publications Warehouse

    Johnson-Thibaut, Penny M.; Demcheck, Dennis K.; Swarzenski, Christopher M.; Ensminger, Paul A.

    1998-01-01

    Approximately 170 Mgal/d (million gallons per day) of ground- and surface-water was withdrawn from the Barataria-Terrebonne Basins in 1995. Of this amount, surface water accounted for 64 percent ( 110 MgaVd) of the total withdrawal rates in the basins. The largest surface-water withdrawal rates were from Bayou Lafourche ( 40 Mgal/d), Bayou Boeuf ( 14 MgaVd), and the Gulf Intracoastal Waterway (4.2 Mgal/d). The largest ground-water withdrawal rates were from the Mississippi River alluvial aquifer (29 Mgal/d), the Gonzales-New Orleans aquifer (9.5 Mgal/d), and the Norco aquifer (3.6 MgaVd). The amounts of water withdrawn in the basins in 1995 differed by category of use. Public water suppliers within the basins withdrew 41 Mgal/d of water. The five largest public water suppliers in the basins withdrew 30 Mgal/d of surface water: Terrebonne Waterworks District 1 withdrew the largest amount, almost 15 MgaVd. Industrial facilities withdrew 88 Mgal/d, fossil-fuel plants withdrew 4.7 MgaVd, and commercial facilities withdrew 0.67 MgaVd. Aggregate water-withdrawal rates, compiled by parish for aquaculture (37 Mgal/d), livestock (0.56 Mgal/d), rural domestic (0.44 MgaVd), and irrigation uses (0.54 MgaVd), totaled about 38 MgaVd in the basins. Ninety-five percent of aquaculture withdrawal rates, primarily for crawfish and alligator farming, were from surface-water sources. >br> Total water-withdrawal rates increased 221 percent from 1960–95. Surface-water withdrawal rates have increased by 310 percent, and ground-water withdrawal rates have increased by 133 percent. The projection for the total water-withdrawal rates in 2020 is 220 MgaVd, an increase of 30 percent from 1995. Surface-water withdrawal rates would account for 59 percent of the total, or 130 Mgal/d. Surface-water withdrawal rates are projected to increase by 20 percent from 1995 to 2020. Analysis of water-quality data from the Mississippi River indicates that the main threats to surface water resources are

  16. Polymorphisms in the interleukin-10 gene and chronic periodontitis in patients with atherosclerotic and aortic aneurysmal vascular diseases

    PubMed Central

    Armingohar, Zahra; Jørgensen, Jørgen J.; Kristoffersen, Anne K.; Schenck, Karl; Dembic, Zlatko

    2015-01-01

    Background Chronic periodontitis (CP), atherosclerotic and aortic aneurysmal vascular diseases (VD) are chronic inflammatory conditions with multifactorial etiologies, including involvement of predisposing genetic factors. In a previous study, polymorphisms in the gene for the anti-inflammatory interleukin-1 receptor antagonist were associated with CP in patients with VD. Objective This study investigates whether polymorphisms in the gene for the anti-inflammatory interleukin-10 (IL10) could be related to CP in the same manner. Methods Seventy-two patients with VD of whom 35 had CP were genotyped for single nucleotide polymorphisms (SNPs) in the IL10 −592 (rs1800872), −819 (rs1800871), and −1,082 (rs1800896) gene by Taqman rtPCR method and by DNA sequencing. Results The C alleles and C/C genotypes of IL10 −592 and IL10 −819 frequencies were significantly higher, while the frequencies of the IL10 −592 (C/A) and IL10 −819 (C/T) heterozygote genotypes were significantly lower in the VD group with CP compared to those without CP. The IL10 haplotype ATA frequency (−1,082, −819, −592) showed a trend to a significant difference between the two groups indicating protection against CP. Conclusions Taken together, our findings suggest an independent association of genetic polymorphisms in the IL-10 gene locus with CP in patients with VD. Development of CP and the implications on vascular disease emphasize the importance of early detection and adequate treatment of periodontitis among these patients. PMID:25700628

  17. Initial dosing regimen of vancomycin to achieve early therapeutic plasma concentration in critically ill patients with MRSA infection based on APACHE II score.

    PubMed

    Imaura, Masaharu; Yokoyama, Haruko; Kohata, Yuji; Kanai, Riichiro; Kohyama, Tomoki; Idemitsu, Wataru; Maki, Yuichi; Igarashi, Takashi; Takahashi, Hiroyuki; Kanno, Hiroshi; Yamada, Yasuhiko

    2016-06-01

    It is essential to assure the efficacy of antimicrobials at the initial phase of therapy. However, increasing the volume of distribution (Vd) of hydrophilic antimicrobials in critically ill patients leads to reduced antimicrobial concentration in plasma and tissue, which may adversely affect the efficacy of that therapy. The aim of the present study was to establish a theoretical methodology for setting an appropriate level for initial vancomycin therapy in individual patients based on Acute Physiology and Chronic Health Evaluation (APACHE) II score. We obtained data from patients who received intravenous vancomycin for a suspected or definitively diagnosed Gram-positive bacterial infection within 72 h after admission to the intensive care unit. The Vd and elimination half-life (t 1/2) of vancomycin values were calculated using the Bayesian method, and we investigated the relationship between them and APACHE II score. There were significant correlations between APACHE II scores and Vd/actual body weight (ABW), as well as t 1/2 (r = 0.58, p < 0.05 and r = 0.74, p < 0.01, respectively). Our results suggested that the Vd and t 1/2 of vancomycin could be estimated using the following regression equations using APACHE II score.[Formula: see text] [Formula: see text]We found that APACHE II score was a useful index for predicting the Vd and t 1/2 of vancomycin, and used that to establish an initial vancomycin dosing regimen comprised of initial dose and administration interval for individual patients.

  18. A Universal Power-law Profile of Pseudo-phase-space Density-like Quantities in Elliptical Galaxies

    NASA Astrophysics Data System (ADS)

    Chae, Kyu-Hyun

    2014-06-01

    We study profiles of mass density, velocity dispersion (VD), and a combination of both using ~2000 nearly spherical and rotation-free Sloan Digital Sky Survey galaxies. For observational stellar mass density ρsstarf(r), we consider a range of dark matter (DM) distribution ρDM(r) and VD anisotropy β(r) to investigate radial stellar VD σsstarfr(r) using the spherical Jeans equation. While mass and VD profiles vary appreciably depending on DM distribution and anisotropy, the pseudo-phase-space density-like combination \\rho (r)/\\sigma _\\star r^3(r) with total density ρ(r) = ρsstarf(r) + ρDM(r) is nearly universal. In the optical region, the negative logarithmic slope has a mean value of langχrang ≈ 1.86-1.90 with a galaxy-to-galaxy rms scatter of ≈0.04-0.06, which is a few times smaller than that of ρ(r) profiles. The scatter of χ can be increased by invoking wildly varying anisotropies that are, however, less likely because they would produce too large a scatter of line of sight VD profiles. As an independent check of this universality, we analyze stellar orbit-based dynamical models of 15 early-type galaxies (ETGs) of the Coma cluster provided by J. Thomas. Coma ETGs, with σsstarfr(r) replaced by the rms velocity of stars v sstarfrms(r) including net rotation, exhibit a similar universality with a slope of χ = 1.93 ± 0.06. Remarkably, the inferred values of χ for ETGs match well the slope ≈1.9 predicted by N-body simulations of DM halos. We argue that the inferred universal nature of \\rho (r)/\\sigma _\\star r^3(r) cannot be fully explained by equilibrium alone, implying that some astrophysical factors conspire and/or it reflects a fundamental principle in collisionless formation processes.

  19. Salutary effect of gastric pentadecapeptide BPC 157 in two different stress urinary incontinence models in female rats

    PubMed Central

    Jandric, Ivan; Vrcic, Hrvoje; Balen, Marica Jandric; Kolenc, Danijela; Brcic, Luka; Radic, Bozo; Drmic, Domagoj; Seiwerth, Sven; Sikiric, Predrag

    2013-01-01

    Background Since an originally anti-ulcer stable gastric pentadecapeptide BPC 157 (PL 14736) was shown to promote healing of injured striated muscle and smooth muscle in the gastrointestinal tract, we explored its therapeutic potentials for leak point pressure (LPP) recovery in rat stress urinary incontinence (SUI) after transabdominal urethrolysis (TU) and prolonged vaginal dilatation (VD). Material/Methods During a 7-day period, TU-rats and VD-rats (or healthy rats) received BPC 157, either (i) intraperitoneally, 10 μg/kg or 10 ng/kg, once daily (first administration 30 min after surgery, last 24 h before LPP-testing and sacrifice), or (ii) per-orally, 10 μg/kg in drinking water (0.16 μg/mL, 12 mL/rat/day). Vesicourethral segments were harvested for immunohistochemical evaluation. Results All BPC 157 regimens counteracted decrease of LPP values in TU-rats and VD-rats. Additionally, BPC 157-TU rats (μg-intraperitoneally or per-orally) and BPC 157-VD rats (μg intraperitoneally) reached LPP values originally noted in healthy rats. Conversely, in healthy rats, BPC 157 did not alter LPP. Immunohistochemical studies revealed higher desmin (delineates striated organization of skeletal muscle), smooth muscle actin, and CD34 (angiogenic marker) positivity within the urethral wall in BPC 157-treated rats vs. controls, as well as overall preserved muscle/connective tissue ratio assessed with Mallory’s trichrome staining. Conclusions Pentadecapeptide BPC 157, applied parenterally or per-orally, appears to ameliorate the SUI in rat models, improving the otherwise detrimental course of healing after VD and TU, which may be analogous to human injury. These beneficial effects may possibly be selectively used in future strategies for treatment of SUI. PMID:23478678

  20. Robust angle-independent blood velocity estimation based on dual-angle plane wave imaging.

    PubMed

    Fadnes, Solveig; Ekroll, Ingvild Kinn; Nyrnes, Siri Ann; Torp, Hans; Lovstakken, Lasse

    2015-10-01

    Two-dimensional blood velocity estimation has shown potential to solve the angle-dependency of conventional ultrasound flow imaging. Clutter filtering, however, remains a major challenge for large beam-to-flow angles, leading to signal drop-outs and corrupted velocity estimates. This work presents and evaluates a compounding speckle tracking (ST) algorithm to obtain robust angle-independent 2-D blood velocity estimates for all beam-to-flow angles. A dual-angle plane wave imaging setup with full parallel receive beamforming is utilized to achieve high-frame-rate speckle tracking estimates from two scan angles, which may be compounded to obtain velocity estimates of increased robustness. The acquisition also allows direct comparison with vector Doppler (VD) imaging. Absolute velocity bias and root-mean-square (RMS) error of the compounding ST estimations were investigated using simulations of a rotating flow phantom with low velocities ranging from 0 to 20 cm/s. In a challenging region where the estimates were influenced by clutter filtering, the bias and RMS error for the compounding ST estimates were 11% and 2 cm/s, a significant reduction compared with conventional single-angle ST (22% and 4 cm/s) and VD (36% and 6 cm/s). The method was also tested in vivo for vascular and neonatal cardiac imaging. In a carotid artery bifurcation, the obtained blood velocity estimates showed that the compounded ST method was less influenced by clutter filtering than conventional ST and VD methods. In the cardiac case, it was observed that ST velocity estimation is more affected by low signal-to-noise (SNR) than VD. However, with sufficient SNR the in vivo results indicated that a more robust angle-independent blood velocity estimator is obtained using compounded speckle tracking compared with conventional ST and VD methods. PMID:26470038

  1. Two-dimensional GaSe/MoSe2 misfit bilayer heterojunctions by van der Waals epitaxy.

    PubMed

    Li, Xufan; Lin, Ming-Wei; Lin, Junhao; Huang, Bing; Puretzky, Alexander A; Ma, Cheng; Wang, Kai; Zhou, Wu; Pantelides, Sokrates T; Chi, Miaofang; Kravchenko, Ivan; Fowlkes, Jason; Rouleau, Christopher M; Geohegan, David B; Xiao, Kai

    2016-04-01

    Two-dimensional (2D) heterostructures hold the promise for future atomically thin electronics and optoelectronics because of their diverse functionalities. Although heterostructures consisting of different 2D materials with well-matched lattices and novel physical properties have been successfully fabricated via van der Waals (vdW) epitaxy, constructing heterostructures from layered semiconductors with large lattice misfits remains challenging. We report the growth of 2D GaSe/MoSe2 heterostructures with a large lattice misfit using two-step chemical vapor deposition (CVD). Both vertically stacked and lateral heterostructures are demonstrated. The vertically stacked GaSe/MoSe2 heterostructures exhibit vdW epitaxy with well-aligned lattice orientation between the two layers, forming a periodic superlattice. However, the lateral heterostructures exhibit no lateral epitaxial alignment at the interface between GaSe and MoSe2 crystalline domains. Instead of a direct lateral connection at the boundary region where the same lattice orientation is observed between GaSe and MoSe2 monolayer domains in lateral GaSe/MoSe2 heterostructures, GaSe monolayers are found to overgrow MoSe2 during CVD, forming a stripe of vertically stacked vdW heterostructures at the crystal interface. Such vertically stacked vdW GaSe/MoSe2 heterostructures are shown to form p-n junctions with effective transport and separation of photogenerated charge carriers between layers, resulting in a gate-tunable photovoltaic response. These GaSe/MoSe2 vdW heterostructures should have applications as gate-tunable field-effect transistors, photodetectors, and solar cells. PMID:27152356

  2. Comparison between the interactions of adenovirus-derived peptides with plasmid DNA and their role in gene delivery mediated by liposome-peptide-DNA virus-like nanoparticles.

    PubMed

    Preuss, Monika; Tecle, Miriam; Shah, Imran; Matthews, David A; Miller, Andrew D

    2003-07-21

    Previously we have described the development and applications of an important new platform system for gene delivery known as liposome-mu-DNA (LMD), prepared from cationic liposomes (L), plasmid DNA (D) and the mu(M) peptide derived from the adenovirus core. In an attempt to improve upon mu, an alternative peptide (pepV) derived from the adenovirus peptide/protein-DNA core complex was identified, synthesised and studied alongside mu using a number of biophysical techniques including gel retardation, ethidium bromide exclusion, CD binding titration, DNA melting, and plasmid protection assays. PepV binds to pDNA less efficiently than mu but is able to charge neutralise and condense pDNA into negatively charged pepVD particles comparable in dimension to MD particles. The results of CD studies and plasmid protection assays suggest that peptide-DNA interactions are likely to cause pDNA condensation by a combination of charge neutralisation, base pair tilting, double helix destabilisation and the induction of pDNA superfolding. Data suggest the pepVD particles may be formulated with cationic liposomes to give defined LpepVD particles that appear to transfect HeLa cells with marginally more efficiency than LMD particles suggesting that pepV may have some effect on the pDNA transcription process. Although pepV harbours a nuclear-nucleolar localisation sequence (NLS), transfection data show that this capacity is not being appropriately harnessed by the current LpepVD formulation. Further improvements may be required in terms of optimising LpepVD formulations--for instance, to ensure the integrity of the peptide-DNA complexes following cell entry--in order to fully exploit the full NLS capacity of the peptide, thereby facilitating the transfection of slowly dividing or quiescent cells.

  3. Application of van der Waals functionals to the calculation of dissociative adsorption of N2 on W(110) for static and dynamic systems.

    PubMed

    Migliorini, Davide; Nattino, Francesco; Kroes, Geert-Jan

    2016-02-28

    The fundamental understanding of molecule-surface reactions is of great importance to heterogeneous catalysis, motivating many theoretical and experimental studies. Even though much attention has been dedicated to the dissociative chemisorption of N2 on tungsten surfaces, none of the existing theoretical models has been able to quantitatively reproduce experimental reaction probabilities for the sticking of N2 to W(110). In this work, the dissociative chemisorption of N2 on W(110) has been studied with both static electronic structure and ab initio molecular dynamics (AIMD) calculations including the surface temperature effects through surface atom motion. Calculations have been performed using density functional theory, testing functionals that account for the long range van der Waals (vdW) interactions, which were previously only considered in dynamical calculations within the static surface approximation. The vdW-DF2 functional improves the description of the potential energy surface for N2 on W(110), returning less deep molecular adsorption wells and a better ratio between the barriers for the indirect dissociation and the desorption, as suggested by previous theoretical work and experimental evidence. Using the vdW-DF2 functional less trapping-mediated dissociation is obtained compared to results obtained with standard semi-local functionals such as PBE and RPBE, improving agreement with experimental data at E(i) = 0.9 eV. However, at E(i) = 2.287 and off-normal incidence, the vdW-DF2 AIMD underestimates the experimental reaction probabilities, showing that also with the vdW-DF2 functional the N2 on W(110) interaction is not yet described with quantitative accuracy. PMID:26931713

  4. Comparative study of van der Waals corrections to the bulk properties of graphite.

    PubMed

    Rêgo, Celso R C; Oliveira, Luiz N; Tereshchuk, Polina; Da Silva, Juarez L F

    2015-10-21

    Graphite is a stack of honeycomb (graphene) layers bound together by nonlocal, long-range van der Waals (vdW) forces, which are poorly described by density functional theory (DFT) within local or semilocal exchange-correlation functionals. Several approximations have been proposed to add a vdW correction to the DFT total energies (Stefan Grimme (D2 and D3) with different damping functions (D3-BJ), Tkatchenko-Scheffler (TS) without and with self-consistent screening (TS  +  SCS) effects). Those corrections have remarkly improved the agreement between our results and experiment for the interlayer distance (from 3.9 to 0.6%) [corrected] and high-level random-phase approximation (RPA) calculations for interlayer binding energy (from 69.5 to 1.5%). [corrected]. We report a systematic investigation of various structural, energetic and electron properties with the aforementioned vdW corrections followed by comparison with experimental and theoretical RPA data. Comparison between the resulting relative errors shows that the TS  +  SCS correction provides the best results; the other corrections yield significantly larger errors for at least one of the studied properties. If considerations of computational costs or convergence problems rule out the TS  +  SCS approach, we recommend the D3-BJ correction. Comparison between the computed π(z)Γ-splitting and experimental results shows disagreements of 10% or more with all vdW corrections. Even the computationally more expensive hybrid PBE0 has proved unable to improve the agreement with the measured splitting. Our results indicate that improvements of the exchange-correlation functionals beyond the vdW corrections are necessary to accurately describe the band structure of graphite.

  5. Practical Schemes for Accurate Forces in Quantum Monte Carlo.

    PubMed

    Moroni, S; Saccani, S; Filippi, C

    2014-11-11

    While the computation of interatomic forces has become a well-established practice within variational Monte Carlo (VMC), the use of the more accurate Fixed-Node Diffusion Monte Carlo (DMC) method is still largely limited to the computation of total energies on structures obtained at a lower level of theory. Algorithms to compute exact DMC forces have been proposed in the past, and one such scheme is also put forward in this work, but remain rather impractical due to their high computational cost. As a practical route to DMC forces, we therefore revisit here an approximate method, originally developed in the context of correlated sampling and named here the Variational Drift-Diffusion (VD) approach. We thoroughly investigate its accuracy by checking the consistency between the approximate VD force and the derivative of the DMC potential energy surface for the SiH and C2 molecules and employ a wide range of wave functions optimized in VMC to assess its robustness against the choice of trial function. We find that, for all but the poorest wave function, the discrepancy between force and energy is very small over all interatomic distances, affecting the equilibrium bond length obtained with the VD forces by less than 0.004 au. Furthermore, when the VMC forces are approximate due to the use of a partially optimized wave function, the DMC forces have smaller errors and always lead to an equilibrium distance in better agreement with the experimental value. We also show that the cost of computing the VD forces is only slightly larger than the cost of calculating the DMC energy. Therefore, the VD approximation represents a robust and efficient approach to compute accurate DMC forces, superior to the VMC counterparts.

  6. Mechanistic Origin of the Ultrastrong Adhesion between Graphene and a-SiO2: Beyond van der Waals.

    PubMed

    Kumar, Sandeep; Parks, David; Kamrin, Ken

    2016-07-26

    The origin of the ultrastrong adhesion between graphene and a-SiO2 has remained a mystery. This adhesion is believed to be predominantly van der Waals (vdW) in nature. By rigorously analyzing recently reported blistering and nanoindentation experiments, we show that the ultrastrong adhesion between graphene and a-SiO2 cannot be attributed to vdW forces alone. Our analyses show that the fracture toughness of the graphene/a-SiO2 interface, when the interfacial adhesion is modeled with vdW forces alone, is anomalously weak compared to the measured values. The anomaly is related to an ultrasmall fracture process zone (FPZ): owing to the lack of a third dimension in graphene, the FPZ for the graphene/a-SiO2 interface is extremely small, and the combination of predominantly tensile vdW forces, distributed over such a small area, is bound to result in a correspondingly small interfacial fracture toughness. Through multiscale modeling, combining the results of finite element analysis and molecular dynamics simulations, we show that the adhesion between graphene and a-SiO2 involves two different kinds of interactions: one, a weak, long-range interaction arising from vdW adhesion and, second, discrete, short-range interactions originating from graphene clinging to the undercoordinated Si (≡Si·) and the nonbridging O (≡Si-O·) defects on a-SiO2. A strong resistance to relative opening and sliding provided by the latter mechanism is identified as the operative mechanism responsible for the ultrastrong adhesion between graphene and a-SiO2. PMID:27347793

  7. The van der Waals Interaction between a Spherical Particle and a Cylinder.

    PubMed

    Gu; Li

    1999-09-01

    Based on the Hamaker approach, this paper presents a general method to compute the retarded van der Waals (vdW) interaction potential and force between a spherical particle and a cylinder. The effects of the relative dimensions of the cylinder to the sphere were examined by this general method. First, the unretarded vdW interaction potential between these two bodies is obtained by pairwise summation of all the relevant intermolecular interactions and evaluated by accurate multiple numerical integrations. The interaction potential is then modified to account for the retardation effect by incorporating a correction factor which depends on the separation distance and the characteristic wavelength of the interactions. The numerical predictions indicate that the vdW interaction between a sphere and a finitely long cylinder can be approximated as the interaction between a sphere and an infinitely long cylinder only if the ratio of the cylinder length to its radius, B = L/R, is greater than a certain lower limit, say, B > 10. At smaller dimensionless separation distances, H = D/a vdW interaction between a sphere and a cylinder can be approximated by that between a sphere and a flat plate. However, such a commonly used flat plate approximation is found to be acceptable only if the ratio of the cylinder radius to the sphere radius, A = R/a, is larger than 10, regardless of the B value. Otherwise, it will seriously overestimate the vdW interaction for the sphere-cylinder system. Copyright 1999 Academic Press.

  8. Plus Disease in Retinopathy of Prematurity: Development of Composite Images by Quantification of Expert Opinion

    PubMed Central

    Chiang, Michael F.; Gelman, Rony; Williams, Steven L.; Lee, Joo-Yeon; Casper, Daniel S.; Martinez-Perez, M. Elena; Flynn, John T.

    2008-01-01

    Purpose To demonstrate a methodology for generating composite wide-angle images of plus disease in retinopathy of prematurity (ROP), using quantitative analysis of expert opinions. Methods Thirty-four wide-angle retinal images were independently interpreted by 22 ROP experts as “plus” or “not plus.” All images were processed by the computer-based Retinal Image multiScale Analysis (RISA) system to calculate two parameters: arterial integrated curvature (AIC) and venous diameter (VD). Using a reference standard defined by expert consensus, sensitivity and specificity curves were calculated by varying the diagnostic cutoffs for AIC and VD. From these curves, individual vessels from multiple images were identified with particular diagnostic cutoffs, and were combined into composite wide-angle images using graphics-editing software. Results The values associated with 75% underdiagnosis of true plus disease (i.e., 25% sensitivity cutoff) were AIC 0.061 and VD 4.272, the values associated with 50% underdiagnosis of true plus disease (i.e., a 50% sensitivity cutoff) were AIC 0.049 and VD 4.088, and the values associated with 25% underdiagnosis of true plus disease (i.e., 75% sensitivity cutoff) were AIC 0.042 and VD 3.795. Composite wide-angle images were generated by identifying and combining individual vessels with these characteristics. Conclusions Computer-based image analysis permits quantification of retinal vascular features, and a spectrum of abnormalities is seen in ROP. Selection of appropriate vessels from multiple images can produce composite plus disease images corresponding to expert opinions. This method may be useful for educational purposes, and for development of future disease definitions based on objective, quantitative principles. PMID:18408188

  9. Robust angle-independent blood velocity estimation based on dual-angle plane wave imaging.

    PubMed

    Fadnes, Solveig; Ekroll, Ingvild Kinn; Nyrnes, Siri Ann; Torp, Hans; Lovstakken, Lasse

    2015-10-01

    Two-dimensional blood velocity estimation has shown potential to solve the angle-dependency of conventional ultrasound flow imaging. Clutter filtering, however, remains a major challenge for large beam-to-flow angles, leading to signal drop-outs and corrupted velocity estimates. This work presents and evaluates a compounding speckle tracking (ST) algorithm to obtain robust angle-independent 2-D blood velocity estimates for all beam-to-flow angles. A dual-angle plane wave imaging setup with full parallel receive beamforming is utilized to achieve high-frame-rate speckle tracking estimates from two scan angles, which may be compounded to obtain velocity estimates of increased robustness. The acquisition also allows direct comparison with vector Doppler (VD) imaging. Absolute velocity bias and root-mean-square (RMS) error of the compounding ST estimations were investigated using simulations of a rotating flow phantom with low velocities ranging from 0 to 20 cm/s. In a challenging region where the estimates were influenced by clutter filtering, the bias and RMS error for the compounding ST estimates were 11% and 2 cm/s, a significant reduction compared with conventional single-angle ST (22% and 4 cm/s) and VD (36% and 6 cm/s). The method was also tested in vivo for vascular and neonatal cardiac imaging. In a carotid artery bifurcation, the obtained blood velocity estimates showed that the compounded ST method was less influenced by clutter filtering than conventional ST and VD methods. In the cardiac case, it was observed that ST velocity estimation is more affected by low signal-to-noise (SNR) than VD. However, with sufficient SNR the in vivo results indicated that a more robust angle-independent blood velocity estimator is obtained using compounded speckle tracking compared with conventional ST and VD methods.

  10. Comparative study of van der Waals corrections to the bulk properties of graphite

    NASA Astrophysics Data System (ADS)

    Rêgo, Celso R. C.; Oliveira, Luiz N.; Tereshchuk, Polina; Da Silva, Juarez L. F.

    2015-10-01

    Graphite is a stack of honeycomb (graphene) layers bound together by nonlocal, long-range van der Waals (vdW) forces, which are poorly described by density functional theory (DFT) within local or semilocal exchange-correlation functionals. Several approximations have been proposed to add a vdW correction to the DFT total energies (Stefan Grimme (D2 and D3) with different damping functions (D3-BJ), Tkatchenko-Scheffler (TS) without and with self-consistent screening (TS  +  SCS) effects). Those corrections have remarkly improved the agreement between our results and experiment for the interlayer distance (from 3.8 to 0.1%) and high-level random-phase approximation (RPA) calculations for interlayer binding energy (from 56.2 to 0.6%). We report a systematic investigation of various structural, energetic and electron properties with the aforementioned vdW corrections followed by comparison with experimental and theoretical RPA data. Comparison between the resulting relative errors shows that the TS  +  SCS correction provides the best results; the other corrections yield significantly larger errors for at least one of the studied properties. If considerations of computational costs or convergence problems rule out the TS  +  SCS approach, we recommend the D3-BJ correction. Comparison between the computed {πz}Γ\\text{ } -splitting and experimental results shows disagreements of 10% or more with all vdW corrections. Even the computationally more expensive hybrid PBE0 has proved unable to improve the agreement with the measured splitting. Our results indicate that improvements of the exchange-correlation functionals beyond the vdW corrections are necessary to accurately describe the band structure of graphite.

  11. Nitric acid dry deposition to conifer forests: Niwot Ridge spruce-fir-pine study

    USGS Publications Warehouse

    Sievering, H.; Kelly, T.; McConville, G.; Seibold, C.; Turnipseed, A.

    2001-01-01

    The dry deposition velocity of nitric acid, Vd(HNO3), over a 12-m (mean height) spruce-fir forest at Niwot Ridge, Colorado was estimated during 13 daytime periods using the flux-gradient approach. Turbulence intensity at this site is high (mean u* of 0.65ms-1 with u of 2.9ms-1) and contributed to the large observed Vd(HNO3). The overriding contributor is identified to be the small aerodynamic needle width of the conifer trees. Two cases had inflated Vd(HNO3) due to height-differentiated nitric acid loss to soil-derived particle surfaces. Not considering these cases, the mean Vd(HNO3) was 7.6cms-1. The mean laminar boundary layer resistance (Rb) was found to be 7.8sm-1 (of similar magnitude to that of the aerodynamic resistance, 8.5sm-1). The data-determined Rb is bracketed by two theoretical estimates of the mean Rb, 5.9 and 8.6sm-1, that include consideration of the small canopy length scale (aerodynamic needle width), 1mm or less, at this conifer forest. However, the poor correlation of data-determined Rb values with both sets of theoretical estimates indicates that measurement error needs to be reduced and/or improved formulations of theoretical Rb values are in order. The large observed Vd(HNO3) at this conifer forest site is attributed to high turbulence intensity, and, especially, to small aerodynamic needle width. Copyright ?? 2001 Elsevier Science Ltd.

  12. Bacteria and bacterial DNA in atherosclerotic plaque and aneurysmal wall biopsies from patients with and without periodontitis

    PubMed Central

    Armingohar, Zahra; Jørgensen, Jørgen J.; Kristoffersen, Anne Karin; Abesha-Belay, Emnet; Olsen, Ingar

    2014-01-01

    Background Several studies have reported an association between chronic periodontitis (CP) and cardiovascular diseases. Detection of periodontopathogens, including red complex bacteria (RCB), in vascular lesions has suggested these bacteria to be involved in the pathogenesis of atherosclerosis and abdominal aortic aneurysms. Objective In this study, we investigate bacteria and their DNA in vascular biopsies from patients with vascular diseases (VD; i.e. abdominal aortic aneurysms, atherosclerotic carotid, and common femoral arteries), with and without CP. Methods DNA was extracted from vascular biopsies selected from 40 VD patients: 30 with CP and 10 without CP. The V3-V5 region of the 16S rDNA (V3-V5) was polymerase chain reaction (PCR)-amplified, and the amplicons were cloned into Escherichia coli, sequenced, and classified (GenBank and the Human Oral Microbiome database). Species-specific primers were used for the detection of Porphyromonas gingivalis. In addition, 10 randomly selected vascular biopsies from the CP group were subjected to scanning electron microscopy (SEM) for visualization of bacteria. Checkerboard DNA–DNA hybridization was performed to assess the presence of RCB in 10 randomly selected subgingival plaque samples from CP patients. Results A higher load and mean diversity of bacteria were detected in vascular biopsies from VD patients with CP compared to those without CP. Enterobacteriaceae were frequently detected in vascular biopsies together with cultivable, commensal oral, and not-yet-cultured bacterial species. While 70% of the subgingival plaque samples from CP patients showed presence of RCB, only P. gingivalis was detected in one vascular biopsy. Bacterial cells were seen in all 10 vascular biopsies examined by SEM. Conclusions A higher bacterial load and more diverse colonization were detected in VD lesions of CP patients as compared to patients without CP. This indicated that a multitude of bacterial species both from the gut and the

  13. Pilot study on the bioactivity of vitamin d in the skin after oral supplementation.

    PubMed

    Curiel-Lewandrowski, Clara; Tang, Jean Y; Einspahr, Janine G; Bermudez, Yira; Hsu, Chiu Hsieh; Rezaee, Melika; Lee, Alex H; Tangrea, Joseph; Parnes, Howard L; Alberts, David S; Chow, H-H Sherry

    2015-06-01

    Laboratory studies suggest that vitamin D (VD) supplementation inhibits skin carcinogenesis. However, epidemiologic studies report mixed findings in the association between circulating VD levels and skin cancer risk. We conducted a clinical study to determine whether oral cholecalciferol supplementation would exert direct bioactivity in human skin through modulation of the VD receptor (VDR). We enrolled 25 individuals with serum 25-hydroxyvitamin-D levels <30 ng/mL and with skin photodamage to take 50,000 IU of cholecalciferol biweekly for 8 to 9 weeks. Then, we obtained baseline and end-of-study skin biopsies from photodamaged (PD) and photoprotected (PP) skin, and from benign nevi (BN) and tested for mRNA expression of VDR and cytochrome P450-24 (CYP24), and markers of keratinocytic differentiation. High-dose cholecalciferol supplementation significantly elevated circulating levels of 25-hydroxyvitamin-D (P < 0.0001) and 1,25-dihydroxyvitamin-D (P < 0.0001). VDR expression in PD- and PP-skin showed minimum changes after supplementation. CYP24 expression in PD- and PP-skin was increased after supplementation by 186%, P = 0.08, and 134%, P = 0.07, respectively. In BNs from 11 participants, a trend for higher VDR and CYP24 expression was observed (average of 20%, P = 0.08, and 544%, P = 0.09, respectively). Caspase-14 expression at the basal layer in PD skin samples was the only epidermal differentiation marker that was significantly increased (49%, P < 0.0001). High-dose cholecalciferol supplementation raised serum VD metabolite levels concurrently with CYP24 mRNA and caspase-14 levels in the skin. Our findings of significant variability in the range of VDR and CYP24 expression across study samples represent an important consideration in studies evaluating the role of VD as a skin cancer chemopreventive agent.

  14. Deep Sequencing of Viroid-Derived Small RNAs from Grapevine Provides New Insights on the Role of RNA Silencing in Plant-Viroid Interaction

    PubMed Central

    Gisel, Andreas; Moxon, Simon; Dalmay, Tamas; Bisztray, György; Di Serio, Francesco; Burgyán, József

    2009-01-01

    Background Viroids are circular, highly structured, non-protein-coding RNAs that, usurping cellular enzymes and escaping host defense mechanisms, are able to replicate and move through infected plants. Similarly to viruses, viroid infections are associated with the accumulation of viroid-derived 21–24 nt small RNAs (vd-sRNAs) with the typical features of the small interfering RNAs characteristic of RNA silencing, a sequence-specific mechanism involved in defense against invading nucleic acids and in regulation of gene expression in most eukaryotic organisms. Methodology/Principal Findings To gain further insights on the genesis and possible role of vd-sRNAs in plant-viroid interaction, sRNAs isolated from Vitis vinifera infected by Hop stunt viroid (HSVd) and Grapevine yellow speckle viroid 1 (GYSVd1) were sequenced by the high-throughput platform Solexa-Illumina, and the vd-sRNAs were analyzed. The large majority of HSVd- and GYSVd1-sRNAs derived from a few specific regions (hotspots) of the genomic (+) and (−) viroid RNAs, with a prevalence of those from the (−) strands of both viroids. When grouped according to their sizes, vd-sRNAs always assumed a distribution with prominent 21-, 22- and 24-nt peaks, which, interestingly, mapped at the same hotspots. Conclusions/Significance These findings show that different Dicer-like enzymes (DCLs) target viroid RNAs, preferentially accessing to the same viroid domains. Interestingly, our results also suggest that viroid RNAs may interact with host enzymes involved in the RNA-directed DNA methylation pathway, indicating more complex scenarios than previously thought for both vd-sRNAs genesis and possible interference with host gene expression. PMID:19890399

  15. Two-dimensional GaSe/MoSe2 misfit bilayer heterojunctions by van der Waals epitaxy.

    PubMed

    Li, Xufan; Lin, Ming-Wei; Lin, Junhao; Huang, Bing; Puretzky, Alexander A; Ma, Cheng; Wang, Kai; Zhou, Wu; Pantelides, Sokrates T; Chi, Miaofang; Kravchenko, Ivan; Fowlkes, Jason; Rouleau, Christopher M; Geohegan, David B; Xiao, Kai

    2016-04-01

    Two-dimensional (2D) heterostructures hold the promise for future atomically thin electronics and optoelectronics because of their diverse functionalities. Although heterostructures consisting of different 2D materials with well-matched lattices and novel physical properties have been successfully fabricated via van der Waals (vdW) epitaxy, constructing heterostructures from layered semiconductors with large lattice misfits remains challenging. We report the growth of 2D GaSe/MoSe2 heterostructures with a large lattice misfit using two-step chemical vapor deposition (CVD). Both vertically stacked and lateral heterostructures are demonstrated. The vertically stacked GaSe/MoSe2 heterostructures exhibit vdW epitaxy with well-aligned lattice orientation between the two layers, forming a periodic superlattice. However, the lateral heterostructures exhibit no lateral epitaxial alignment at the interface between GaSe and MoSe2 crystalline domains. Instead of a direct lateral connection at the boundary region where the same lattice orientation is observed between GaSe and MoSe2 monolayer domains in lateral GaSe/MoSe2 heterostructures, GaSe monolayers are found to overgrow MoSe2 during CVD, forming a stripe of vertically stacked vdW heterostructures at the crystal interface. Such vertically stacked vdW GaSe/MoSe2 heterostructures are shown to form p-n junctions with effective transport and separation of photogenerated charge carriers between layers, resulting in a gate-tunable photovoltaic response. These GaSe/MoSe2 vdW heterostructures should have applications as gate-tunable field-effect transistors, photodetectors, and solar cells.

  16. Two-dimensional GaSe/MoSe2 misfit bilayer heterojunctions by van der Waals epitaxy

    PubMed Central

    Li, Xufan; Lin, Ming-Wei; Lin, Junhao; Huang, Bing; Puretzky, Alexander A.; Ma, Cheng; Wang, Kai; Zhou, Wu; Pantelides, Sokrates T.; Chi, Miaofang; Kravchenko, Ivan; Fowlkes, Jason; Rouleau, Christopher M.; Geohegan, David B.; Xiao, Kai

    2016-01-01

    Two-dimensional (2D) heterostructures hold the promise for future atomically thin electronics and optoelectronics because of their diverse functionalities. Although heterostructures consisting of different 2D materials with well-matched lattices and novel physical properties have been successfully fabricated via van der Waals (vdW) epitaxy, constructing heterostructures from layered semiconductors with large lattice misfits remains challenging. We report the growth of 2D GaSe/MoSe2 heterostructures with a large lattice misfit using two-step chemical vapor deposition (CVD). Both vertically stacked and lateral heterostructures are demonstrated. The vertically stacked GaSe/MoSe2 heterostructures exhibit vdW epitaxy with well-aligned lattice orientation between the two layers, forming a periodic superlattice. However, the lateral heterostructures exhibit no lateral epitaxial alignment at the interface between GaSe and MoSe2 crystalline domains. Instead of a direct lateral connection at the boundary region where the same lattice orientation is observed between GaSe and MoSe2 monolayer domains in lateral GaSe/MoSe2 heterostructures, GaSe monolayers are found to overgrow MoSe2 during CVD, forming a stripe of vertically stacked vdW heterostructures at the crystal interface. Such vertically stacked vdW GaSe/MoSe2 heterostructures are shown to form p-n junctions with effective transport and separation of photogenerated charge carriers between layers, resulting in a gate-tunable photovoltaic response. These GaSe/MoSe2 vdW heterostructures should have applications as gate-tunable field-effect transistors, photodetectors, and solar cells. PMID:27152356

  17. Atomic structure of metal-halide perovskites from first principles: The chicken-and-egg paradox of the organic-inorganic interaction

    NASA Astrophysics Data System (ADS)

    Li, Jingrui; Rinke, Patrick

    2016-07-01

    We have studied the prototype hybrid organic-inorganic perovskite CH3NH3PbI3 and its three close relatives, CH3NH3SnI3 ,CH3NH3PbCl3 , and CsPbI3, using relativistic density function theory. The long-range van der Waals (vdW) interactions were incorporated into the Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional using the Tkatchenko-Scheffler pairwise scheme. Our results reveal that hydrogen bonding, which is well described by the PBE functional, plays a decisive role for the structural parameters of these systems, including the position and orientation of the organic cation as well as the deformation of the inorganic framework. The magnitude of the inorganic-framework deformation depends sensitively on the orientation of the organic cation, and directly influences the stability of the hybrid perovskites. Our results suggest that the organic and the inorganic components complement each other; the low symmetry of the organic cation is the origin of the inorganic-framework deformation, which then aids the overall stabilization of the hybrid perovskite structure. This stabilization is indirectly affected by vdW interactions, which lead to smaller unit-cell volumes than in PBE and therefore modulate the interaction between the organic cation and the inorganic framework. The vdW-induced lattice-constant corrections are system dependent and lead to PBE+vdW lattice constants in good agreement with experiment. Further insight is gained by analyzing the vdW contributions. In all iodide-based hybrid perovskites, the interaction between the organic cation and the iodide anions provides the largest lattice-constant change, followed by iodine-iodine and the organic cation—heavy-metal cation interaction. These corrections follow an almost linear dependence on the lattice constant within the range considered in our study and are therefore approximately additive.

  18. EDITORIAL: Van der Waals interactions in advanced materials, in memory of David C Langreth Van der Waals interactions in advanced materials, in memory of David C Langreth

    NASA Astrophysics Data System (ADS)

    Hyldgaard, Per; Rahman, Talat S.

    2012-10-01

    The past decade has seen a dramatic rise in interest in exploring the role that van der Waals (vdW) or dispersion forces play in materials and in material behavior. Part of this stems from the obvious fact that vdW interactions (and other weak forces, such as Casimir) underpin molecular recognition, i.e., nature's approach to search for a match between genes and anti-genes and hence enable biological function. Less obvious is the recognition that vdW interactions affect a multitude of properties of a vast variety of materials in general, some of which also have strong technological applications. While for two atom- or orbital-sized material fragments the dispersive contributions to binding are small compared to those from the better known forms (ionic, covalent, metallic), those between sparse materials (spread over extended areas) can be of paramount importance. For example, an understanding of binding in graphite cannot arise solely from a study of the graphene layers individually, but also requires insight from inter-sheet graphene vdW bonding. It is the extended-area vdW bonding that provides sufficient cohesion to make graphite a robust, naturally occurring material. In fact, it is the vdW-bonded graphite, and not the all-covalently bonded diamond, that is the preferred form of pure carbon under ambient conditions. Also important is the understanding that vdW attraction can attain a dramatic relevance even if the material fragments, the building blocks, are not necessarily parallel from the outset or smooth when viewed in isolation (such as a graphene sheet or a carbon nanotube). This can happen if the building blocks have some softness and flexibility and allow an internal relative alignment to emerge. The vdW forces can then cause increasingly larger parts of the interacting fragments to line up at sub-nanometer separations and thus beget more areas with a sizable vdW bonding contribution. The gecko can scale a wall because it can bring its flexible hairs

  19. How to Communicate Near Earth Objects with the Public - Klet Observatory Experience

    NASA Astrophysics Data System (ADS)

    Ticha, Jana; Tichy, Milos; Kocer, Michal

    2015-08-01

    Near-Earth Object (NEO) research is counted among the most popular parts of communicating astronomy with the public. Increasing research results in the field of Near-Earth Objects as well as impact hazard investigations cause growing interest among general public and media. Furthermore NEO related issues have outstanding educational value. So thus communicating NEO detection, NEO characterization, possible impact effects, space missions to NEOs, ways of mitigation and impact warnings with the public and media belong to the most important tasks of scientists and research institutions.Our institution represents an unique liaison of the small professional research institution devoted especially to NEO studies (the Klet Observatory, Czech Republic) and the educational and public outreach branch (the Observatory and Planetarium Ceske Budejovice, Czech Republic). This all has been giving us an excellent opportunity for bringing NEO information to wider audience. We have been obtaining a wide experience in communicating NEOs with the public more than twenty years.There is a wide spectrum of public outreach tools aimed to NEO research and hazard. As the most useful ones we consider two special on-line magazines (e-zins) devoted to asteroids (www.planetky.cz) and comets (www.komety.cz) in Czech language, educational multimedia presentations for schools at different levels in planetarium, summer excursions for wide public just at the Klet Observatory on the top of the Klet mountain, public lectures, meetings and exhibitions. It seems to be very contributing and favoured by public to have opportunities for more or less informal meetings just with NEO researchers from time to time. Very important part of NEO public outreach consists of continuous contact with journalists and media including press releases, interviews, news, periodical programs. An increasing role of social media is taken into account through Facebook and Twitter profiles.The essential goal of all mentioned NEO

  20. Mycorrhizal symbiosis and local adaptation in Aster amellus: a field transplant experiment.

    PubMed

    Pánková, Hana; Raabová, Jana; Münzbergová, Zuzana

    2014-01-01

    Many plant populations have adapted to local soil conditions. However, the role of arbuscular mycorrhizal fungi is often overlooked in this context. Only a few studies have used reciprocal transplant experiments to study the relationships between soil conditions, mycorrhizal colonisation and plant growth. Furthermore, most of the studies were conducted under controlled greenhouse conditions. However, long-term field experiments can provide more realistic insights into this issue. We conducted a five-year field reciprocal transplant experiment to study the relationships between soil conditions, arbuscular mycorrhizal fungi and plant growth in the obligate mycotrophic herb Aster amellus. We conducted this study in two regions in the Czech Republic that differ significantly in their soil nutrient content, namely Czech Karst (region K) and Ceske Stredohori (region S). Plants that originated from region S had significantly higher mycorrhizal colonisation than plants from region K, indicating that the percentage of mycorrhizal colonisation has a genetic basis. We found no evidence of local adaptation in Aster amellus. Instead, plants from region S outperformed the plants from region K in both target regions. Similarly, plants from region S showed more mycorrhizal colonisation in all cases, which was likely driven by the lower nutrient content in the soil from that region. Thus, plant aboveground biomass and mycorrhizal colonisation exhibited corresponding differences between the two target regions and regions of origin. Higher mycorrhizal colonisation in the plants from region with lower soil nutrient content (region S) in both target regions indicates that mycorrhizal colonisation is an adaptive trait. However, lower aboveground biomass in the plants with lower mycorrhizal colonisation suggests that the plants from region K are in fact maladapted by their low inherent mycorrhizal colonization. We conclude that including mycorrhizal symbiosis in local adaptation studies

  1. Specific argonautes selectively bind small RNAs derived from potato spindle tuber viroid and attenuate viroid accumulation in vivo.

    PubMed

    Minoia, Sofia; Carbonell, Alberto; Di Serio, Francesco; Gisel, Andreas; Carrington, James C; Navarro, Beatriz; Flores, Ricardo

    2014-10-01

    The identification of viroid-derived small RNAs (vd-sRNAs) of 21 to 24 nucleotides (nt) in plants infected by viroids (infectious non-protein-coding RNAs of just 250 to 400 nt) supports their targeting by Dicer-like enzymes, the first host RNA-silencing barrier. However, whether viroids, like RNA viruses, are also targeted by the RNA-induced silencing complex (RISC) remains controversial. At the RISC core is one Argonaute (AGO) protein that, guided by endogenous or viral sRNAs, targets complementary RNAs. To examine whether AGO proteins also load vd-sRNAs, leaves of Nicotiana benthamiana infected by potato spindle tuber viroid (PSTVd) were agroinfiltrated with plasmids expressing epitope-tagged versions of AGO1, AGO2, AGO3, AGO4, AGO5, AGO6, AGO7, AGO9, and AGO10 from Arabidopsis thaliana. Immunoprecipitation analyses of the agroinfiltrated halos revealed that all AGOs except AGO6, AGO7, and AGO10 associated with vd-sRNAs: AGO1, AGO2, and AGO3 preferentially with those of 21 and 22 nt, while AGO4, AGO5, and AGO9 additionally bound those of 24 nt. Deep-sequencing analyses showed that sorting of vd-sRNAs into AGO1, AGO2, AGO4, and AGO5 depended essentially on their 5'-terminal nucleotides, with the profiles of the corresponding AGO-loaded vd-sRNAs adopting specific hot spot distributions along the viroid genome. Furthermore, agroexpression of AGO1, AGO2, AGO4, and AGO5 on PSTVd-infected tissue attenuated the level of the genomic RNAs, suggesting that they, or their precursors, are RISC targeted. In contrast to RNA viruses, PSTVd infection of N. benthamiana did not affect miR168-mediated regulation of the endogenous AGO1, which loaded vd-sRNAs with specificity similar to that of its A. thaliana counterpart. Importance: To contain invaders, particularly RNA viruses, plants have evolved an RNA-silencing mechanism relying on the generation by Dicer-like (DCL) enzymes of virus-derived small RNAs of 21 to 24 nucleotides (nt) that load and guide Argonaute (AGO) proteins to

  2. Nutrient intake and health status of vegans. Chemical analyses of diets using the duplicate portion sampling technique.

    PubMed

    Abdulla, M; Andersson, I; Asp, N G; Berthelsen, K; Birkhed, D; Dencker, I; Johansson, C G; Jägerstad, M; Kolar, K; Nair, B M; Nilsson-Ehle, P; Nordén, A; Rassner, S; Akesson, B; Ockerman, P A

    1981-11-01

    A strict vegetarian diet [vegan diet (VD)] was investigated. Six middle-aged vegans (three men and three women) collected copies of 24-h diets using the duplicate portion sampling technique. By chemical analyses, the nutrient composition was determined in detail and compared with corresponding figures of a normal mixed Swedish diet. In the VD 30% of the energy originated from fat compared with 40% in normal Swedish mixed diet (MD). Linoleic acid was the dominant fatty acid (60% of total fat in VD versus 8% in MD). The VD contained 24 g protein/1000 kcal compared to 30 g/1000 kcal in MD, but the intake of essential amino acids by the vegans exceeded the recommendations. Dietary fiber was about 5 times higher in the vegan diet (29 versus 6 g/1000 kcal) and sucrose similar to MD (18 versus 21 g/1000 kcal). Among the inorganic nutrients the concentration of calcium (351 versus 391 mg/1000 kcal) and sodium (53 versus 49 mmol/1000 kcal) were similar in both types of diets but the amount of potassium (56 versus 30 mmol/1000 kcal, magnesium (300 versus 110 mg/1000 kcal), iron (9 versus 6.5 mg/1000 kcal), zinc (6.5 versus 4.7 mg/1000 kcal), and copper (2 versus 0.7 mg/1000 kcal) were nearly doubled. Iodine (39 versus 156 micrograms/1000 kcal and selenium (5 versus 17 micrograms/1000 kcal) were much lower in the VD, selenium even being undetectable in several 24-h diets. The VD was rich in folic acid (301 versus 90 micrograms/1000 kcal in MD) but the intake of vitamin B12 was only 0.3 to 0.4 microgram/day (MD: 3 to 4 micrograms/day). No clinical signs of nutritional deficiency were observed in the vegans. Serum protein levels of the vegans as well as their serum lipoproteins were near the lower range of the reference group. In addition, none of the vegans was overweight and their blood pressures were low for their age.

  3. Vitamin D Attenuates Kidney Fibrosis via Reducing Fibroblast Expansion, Inflammation, and Epithelial Cell Apoptosis.

    PubMed

    Arfian, Nur; Muflikhah, Khusnul; Soeyono, Sri Kadarsih; Sari, Dwi Cahyani Ratna; Tranggono, Untung; Anggorowati, Nungki; Romi, Muhammad Mansyur

    2016-01-01

    Kidney fibrosis is the common final pathway of chronic kidney diseases (CKD). It is characterized by myofibroblast formation, inflammation, and epithelial architecture damage. Vitamin D is known as a renoprotective agent, although the precise mechanism is not well understood. This study aimed to elucidate the effect of vitamin D in fibroblast expansion, inflammation, and apoptosis in kidney fibrosis. We performed unilateral ureteral obstruction (UUO) in male Swiss-Webster background mice (3 months, 30-40 grams) to induce kidney fibrosis. The mice (n=25) were divided into five groups: UUO, 3 groups treated with different oral vitamin D doses (0.125 µg/kg (UUO+VD1), 0.25 µg/kg (UUO+VD2), and 0.5 µg/kg (UUO+VD3), and a Sham operation (SO) group with ethanol 0.2% supplementation. We sacrificed the mice on day14 after the operation and harvested the kidney. We made paraffin sections for histological analysis. Tubular injury and fibrosis were quantified based on periodic acid-Schiff (PAS) and Sirius Red (SR) staining. Immunostaining was done for examination of myofibroblasts (αSMA), fibroblasts (PDGFRβ), TLR4, and apoptosis (TUNEL). We did RNA extraction and cDNA for Reverse transcriptase PCR (RT-PCR) experiment for measuring MCP-1, ICAM-1, TLR4, and collagen 1 expression. TGFβ1 level was quantified using ELISA. We observed a significantly lower levels of fibrosis (p<0.001), tubular injury scores (p<0.001), and myofibroblast areas (p<0.001) in the groups treated with vitamin D compared with the UUO group. The TGFβ1 levels and the fibroblast quantifications were also significantly lower in the former group. However, we did not find any significant difference among the various vitamin D-treated groups. Concerning the dose-independent effect, we only compared the UUO+VD-1 group with SO group and found by TUNEL assay that UUO+VD-1 had a significantly lower epithelial cell apoptosis. RT-PCR analysis showed lower expression of collagen1, as well as inflammation

  4. Design and rationale of a multicentre, randomised, double-blind, placebo-controlled clinical trial to evaluate the effect of vitamin D on ventricular remodelling in patients with anterior myocardial infarction: the VITamin D in Acute Myocardial Infarction (VITDAMI) trial

    PubMed Central

    Tuñón, José; González-Hernández, Ignacio; Llanos-Jiménez, Lucía; Alonso-Martín, Joaquín; Escudier-Villa, Juan M; Tarín, Nieves; Cristóbal, Carmen; Sanz, Petra; Pello, Ana M; Aceña, Álvaro; Carda, Rocío; Orejas, Miguel; Tomás, Marta; Beltrán, Paula; Calero Rueda, Marta; Marcos, Esther; Serrano-Antolín, José María; Gutiérrez-Landaluce, Carlos; Jiménez, Rosa; Cabezudo, Jorge; Curcio, Alejandro; Peces-Barba, Germán; González-Parra, Emilio; Muñoz-Siscart, Raquel; González-Casaus, María Luisa; Lorenzo, Antonio; Huelmos, Ana; Goicolea, Javier; Ibáñez, Borja; Hernández, Gonzalo; Alonso-Pulpón, Luis M; Farré, Jerónimo; Lorenzo, Óscar; Mahíllo-Fernández, Ignacio; Egido, Jesús

    2016-01-01

    Introduction Decreased plasma vitamin D (VD) levels are linked to cardiovascular damage. However, clinical trials have not demonstrated a benefit of VD supplements on left ventricular (LV) remodelling. Anterior ST-elevation acute myocardial infarction (STEMI) is the best human model to study the effect of treatments on LV remodelling. We present a proof-of-concept study that aims to investigate whether VD improves LV remodelling in patients with anterior STEMI. Methods and analysis The VITamin D in Acute Myocardial Infarction (VITDAMI) trial is a multicentre, randomised, double-blind, placebo-controlled trial. 144 patients with anterior STEMI will be assigned to receive calcifediol 0.266 mg capsules (Hidroferol SGC)/15 days or placebo on a 2:1 basis during 12 months. Primary objective: to evaluate the effect of calcifediol on LV remodelling defined as an increase in LV end-diastolic volume ≥10% (MRI). Secondary objectives: change in LV end-diastolic and end-systolic volumes, ejection fraction, LV mass, diastolic function, sphericity index and size of fibrotic area; endothelial function; plasma levels of aminoterminal fragment of B-type natriuretic peptide, galectin-3 and monocyte chemoattractant protein-1; levels of calcidiol (VD metabolite) and other components of mineral metabolism (fibroblast growth factor-23 (FGF-23), the soluble form of its receptor klotho, parathormone and phosphate). Differences in the effect of VD will be investigated according to the plasma levels of FGF-23 and klotho. Treatment safety and tolerability will be assessed. This is the first study to evaluate the effect of VD on cardiac remodelling in patients with STEMI. Ethics and dissemination This trial has been approved by the corresponding Institutional Review Board (IRB) and National Competent Authority (Agencia Española de Medicamentos y Productos Sanitarios (AEMPS)). It will be conducted in accordance with good clinical practice (International Council for Harmonisation of

  5. Precipitation Properties of Arctic Single-Layer Mixed-Phase Clouds

    NASA Astrophysics Data System (ADS)

    Ohigashi, T.; Kollias, P.; Szyrmer, W.

    2015-12-01

    In the Arctic, single-layer mixed-phase clouds rooted in the boundary layer with cloud top heights between several hundred meters and 2 km are frequently observed. Ice particles grow fast in these mixed-phase clouds and thus produce solid precipitation. Understanding the water cycle in the Arctic region requires an extensive study of the precipitation properties of the Arctic single-layer mixed-phase clouds. The US Department of Energy Atmospheric Radiation Measurement (ARM) facility at Barrow, North Slope of Alaska conducts long-term measurements of mixed-phase clouds using a combination of active and passive sensors. Using the data of 35-GHz (Ka-band) zenith pointing radar (KAZR), ceilometer, and microwave radiometer, 1-hour averaged estimates of mixed-phase clouds are produced. A total of 553 hours of single-layer mixed-phase clouds were visually identified between October 2011 and December 2014. Using the KAZR radar reflectivity measured just one radar range gate (30 m) below the liquid base of the mixed-phase, ice water content (IWC) estimates are derived. The correlation between the hourly-mean liquid water path (LWP) and IWC below the base is not high. On the other hand, the KAZR mean Doppler velocity (Vd) at the same level exhibits high correlation with the LWP. In the LWP regime above 220 g m-2, Vd is larger than 1.0 m s-1. Vd approached to 1.8 m s-1 at even higher LWP values. We assumed that the 1-hour averaged Vd values are representative of the reflectivity-weighted mean terminal velocity of the ice particles. The large terminal velocities cannot be explained if the ice particles grow only via the deposition process. It is suggested that the riming process contributed to the growth of the particles when large terminal velocities are observed. The correlation between LWP and the KAZR Vd near the surface is similarly high. From high correlations between LWP and Vd near the cloud base and near the surface, it is clear that the LWP exhibits some control

  6. Sensitive induction of apoptosis in breast cancer cells by a novel 1,25-dihydroxyvitamin D3 analogue shows relation to promoter selectivity.

    PubMed

    Danielsson, C; Mathiasen, I S; James, S Y; Nayeri, S; Bretting, C; Hansen, C M; Colston, K W; Carlberg, C

    1997-09-15

    The biologically active form of vitamin D3, the nuclear hormone 1 alpha,25-dihydroxyvitamin D3 (VD), is an important regulator of cellular growth, differentiation, and death. The hormone mediates its action through the activation of the transcription factor VDR, which is a member of the superfamily of nuclear receptors. In most cases the ligand-activated VDR is found in complex with the retinoid X receptor (RXR) and stimulates gene transcription mainly from VD response elements (VDREs) that are formed by two hexameric core binding motifs and are arranged either as a direct repeat spaced by three nucleotides (DR3) or as an inverted palindrome spaced by nine nucleotides (1P9). The two VD analogues CB1093 and EB1089 are both very potent inhibitors of the proliferation of MCF-7 cultured breast cancer cells displaying approximately 100-fold lower IC50 values (0.1 nM) than the natural hormone. In addition, CB1093 is even more potent in vivo than EB1089 in producing regression of experimental mammary tumors. Moreover, both VD analogues induce apoptosis in MCF-7 cells, but CB1093 is effective at concentrations approximately 10-fold lower than EB1089. In accordance, the reduction of Bcl-2 protein expression showed CB1093 to be more potent than EB1089. This suggests that the antiproliferative effect of CB1093 may be related mainly to its apoptosis inducing effect, whereas EB1089 may preferentially have effects on growth arrest. EB1089 is known to result in a selectivity for the activation of IP9-type VDREs, whereas CB1093 shows a preference for the activation of DR3-type VDREs. This promoter selectivity suggests that the effects of VD and its analogues on growth arrest and the induction of apoptosis may be mediated by different primary VD responding genes. In conclusion, CB1093 was found to be a potent inhibitor of rat mammary tumor growth in vivo. CB1093 also displayed a high potency in vitro in the induction of apoptosis, a process that may be linked to a promoter

  7. Organotin materials and their solid state properties, and, The utility of NADA in the synthesis of a new metallate synthon

    NASA Astrophysics Data System (ADS)

    Munguia, Teresita

    A series of novel bioactive organometallic materials of the type (o-EMeC 6H4)CH2MR3-nCln were synthesized to form: (1) M = Si, (2) M = Ge, (3) M = Sn, (4) M = Pb [E = S, R = Ph, n = 0], (5) n = 1, (6) n = 2 [M = Sn, R = Ph], (7) n = 0, (8) n = 1 [M = Sn, R = p-(t-BuPh)], (9) n = 0, (10) n = 1, (11) n = 2 [E = O, R = Ph]. Their crystal and molecular structures have been determined and characterized by solution NMR and X-ray crystallography. To further illustrate intramolecular interactions and to understand molecular motions in the solid state of these materials, solid-state 119Sn CPMAS NMR was performed on compounds 3-11 and compared to 119Sn solution state chemical shifts. Analysis shows that the tin atom approaches a pseudo-trigonal bipyramidal pentacoordination as a consequence of intramolecular Sn-S (3, 5-8) and Sn-O (9-11) interactions. The intramolecular Sn-S distances range from 3.699 A and 3.829 A in 3 (88% and 91.2% vdW radii), 3.062 A in 5 (73% vdW radii) and 2.994 A in 6 (71% vdW radii) whereas the Sn-O distances in 9, 10 and 11 are 3.07 A (82.9% the sum of the van der Waal radii), 2.76 A (74.5% vdW radii) and 2.92 A (78.9% vdW radii), respectively. The geometry of compound 11 is additionally complicated by an intermolecular interaction of 3.488 A between Sn in one molecule and Cl in a neighboring molecule creating a distorted octahedral geometry. Furthermore, the utility of CPMAS 119Sn NMR is again illustrated as a second crystal form of 3, 3', which is monoclinic, with one molecule in the unit cell, and a Sn-S distance of 3.973 A (94.6% vdW radii) was discovered.

  8. Abnormal bone mineral density and bone turnover marker expression profiles in patients with primary spontaneous pneumothorax

    PubMed Central

    Yu, Lixin; Hou, Shengcai; Hu, Bin; Zhao, Liqiang; Miao, Jinbai; Wang, Yang; Li, Tong; Zhang, Zhenkui; You, Bin; Pang, Baosen; Liang, Yufang; Zhao, Yi; Hao, Wei

    2016-01-01

    Background To examine the bone mineral density (BMD) and the role of bone biomarkers, including bone formation marker procollagen type I aminoterminal propeptide (PINP) and N-terminal midmolecule fragment osteocalcin (N-MID), bone resorption marker b-C-telopeptides of type I collagen (b-CTX) and tartrate-resistant acid phosphatase 5b (TRACP5b) in the pathogenesis of PSP. Methods Eighty-three consecutive primary spontaneous pneumothorax (PSP) patients (PSP group) and 87 healthy individuals (control group) were enrolled in this study. General data, including gender, age, height, weight, and body mass index (BMI), were recorded. Dual-energy X-ray absorptiometry, electrochemiluminescence immunoassay (ECLIA), and ELISA were used to evaluate bone mineral density and expression levels of bone metabolism markers, including PINP, b-CTX, TRACP5b, N-MID, and 25-hydroxyvitamin D (25-OH VD). Results Mean height was significantly greater in the PSP group compared with the control group, whereas weight and BMI were lower. Patients in the PSP group had significantly lower average bone mineral density, which mainly manifested as osteopenia (11/12, 91.7%); however, only one patient (8.3%) developed osteoporosis. Serum overexpression of PINP, b-CTX, TRACP5b, and N-MID were found in PSP patients. Expression of 25-OH VD was low in PSP patients. Bone resorption markers showed positive linear relationships with bone formation markers in all participants; whereas only TRACP5b expression negatively correlated with 25-OH VD. Expression levels of all bone turnover markers negatively correlated with BMI. Regression analysis identified risk factors of PSP as age, height, weight, and TRACP5b and 25-OH VD expression levels; whereas gender and PINP, b-CTX, and N-MID expression levels were not significantly associated with the onset of PSP. Conclusions It had lower bone mineral density in PSP patients. Bone formation marker PINP, N-MID and bone resorption marker b-CTX, TRACP5b were upregulated in

  9. Application of Molecular Dynamics Simulations in Molecular Property Prediction I: Density and Heat of Vaporization

    PubMed Central

    Wang, Junmei; Tingjun, Hou

    2011-01-01

    Molecular mechanical force field (FF) methods are useful in studying condensed phase properties. They are complementary to experiment and can often go beyond experiment in atomic details. Even a FF is specific for studying structures, dynamics and functions of biomolecules, it is still important for the FF to accurately reproduce the experimental liquid properties of small molecules that represent the chemical moieties of biomolecules. Otherwise, the force field may not describe the structures and energies of macromolecules in aqueous solutions properly. In this work, we have carried out a systematic study to evaluate the General AMBER Force Field (GAFF) in studying densities and heats of vaporization for a large set of organic molecules that covers the most common chemical functional groups. The latest techniques, such as the particle mesh Ewald (PME) for calculating electrostatic energies, and Langevin dynamics for scaling temperatures, have been applied in the molecular dynamics (MD) simulations. For density, the average percent error (APE) of 71 organic compounds is 4.43% when compared to the experimental values. More encouragingly, the APE drops to 3.43% after the exclusion of two outliers and four other compounds for which the experimental densities have been measured with pressures higher than 1.0 atm. For heat of vaporization, several protocols have been investigated and the best one, P4/ntt0, achieves an average unsigned error (AUE) and a root-mean-square error (RMSE) of 0.93 and 1.20 kcal/mol, respectively. How to reduce the prediction errors through proper van der Waals (vdW) parameterization has been discussed. An encouraging finding in vdW parameterization is that both densities and heats of vaporization approach their “ideal” values in a synchronous fashion when vdW parameters are tuned. The following hydration free energy calculation using thermodynamic integration further justifies the vdW refinement. We conclude that simple vdW parameterization

  10. Therapeutic evaluation of sorafenib for hepatocellular carcinoma using contrast-enhanced ultrasonography: Preliminary result

    PubMed Central

    SHIOZAWA, KAZUE; WATANABE, MANABU; IKEHARA, TAKASHI; KOGAME, MICHIO; KIKUCHI, YOSHINORI; IGARASHI, YOSHINORI; SUMINO, YASUKIYO

    2016-01-01

    The present study aimed to determine the usefulness of contrast-enhanced ultrasonography (CEUS) with Sonazoid in evaluating the therapeutic response to sorafenib for hepatocellular carcinoma (HCC). In total, 26 patients with advanced HCC who received sorafenib and were followed up by CEUS were enrolled in the present study. CEUS was performed prior to and within 2–4 weeks of treatment, and the images of the target lesion in the post-vascular phase with a re-injection method were analyzed. The presence (+) or absence (−) of intratumoral necrosis and the intratumoral vascular architecture on micro-flow imaging (MFI) were compared prior to and subsequent to treatment. Target lesions that exhibited non-enhancement after re-injection were considered to indicate intratumoral necrosis. The intratumoral vascular architecture was classified into three groups, as follows: Vd, the intratumoral vessels visually narrowed or decreased; Vnc, the vessels remained unchanged; and Vi, the vessels were thickened or increased. Survival curves were estimated using the Kaplan-Meier method and compared using the log rank test between the intratumoral necrosis (+) and (−) groups, and among the Vd, Vnc and Vi groups. P<0.05 was considered to indicate a statistically significant difference. The number of patients in the intratumoral necrosis (+) and (−) groups was 8 and 18 patients, respectively, and the median survival time (MST) was 7.2 months [95% confidence interval (CI), 2.2–12.2] and 9.5 months (95% CI, 5.1–13.8), respectively (P=0.44). The MFI findings were observed in 11 patients in the Vd group, 10 patients in the Vnc group and 5 patients in the Vi group. The MSTs in the Vd, Vnc and Vi groups were 15.6 months (95% CI, 5.0–23.3), 11.0 months (95% CI, 3.5–17.6) and 3.6 months (95% CI: 1.2–6.0), respectively. The P-value for the differences between the Vd and Vnc groups, Vd and Vi groups, and Vnc and Vi groups were 0.78, 0.016 and 0.047, respectively, which indicated

  11. Molecular dynamics simulation for interlayer interactions of graphene nanoribbons with multiple layers

    NASA Astrophysics Data System (ADS)

    Nazemnezhad, Reza; Zare, Mojtaba; Hosseini-Hashemi, Shahrokh; Shokrollahi, Hassan

    2016-10-01

    A new study is conducted with the aid of molecular dynamics (MD) simulation to investigate the effect of shear modulus value of the interlayer van der Waals (vdWs) interactions on free vibration of cantilever multi-layer graphene nanoribbons (MLGNRs). The corresponding calibrated nonlocal parameters of the nonlocal model are obtained accordingly. The vdWs interactions are treated as the cores between every two adjacent graphene layers and their equivalent shear modulus is calculated using MD simulation. The obtained resonant frequencies via the nonlocal sandwich model are compared to the MD simulation results to calibrate the nonlocal parameter. Results reveal a strong conclusion that the calibrated nonlocal parameter is dependent on the values of interlayer shear modulus.

  12. Wavelike charge density fluctuations and van der Waals interactions at the nanoscale.

    PubMed

    Ambrosetti, Alberto; Ferri, Nicola; DiStasio, Robert A; Tkatchenko, Alexandre

    2016-03-11

    Recent experiments on noncovalent interactions at the nanoscale have challenged the basic assumptions of commonly used particle- or fragment-based models for describing van der Waals (vdW) or dispersion forces. We demonstrate that a qualitatively correct description of the vdW interactions between polarizable nanostructures over a wide range of finite distances can only be attained by accounting for the wavelike nature of charge density fluctuations. By considering a diverse set of materials and biological systems with markedly different dimensionalities, topologies, and polarizabilities, we find a visible enhancement in the nonlocality of the charge density response in the range of 10 to 20 nanometers. These collective wavelike fluctuations are responsible for the emergence of nontrivial modifications of the power laws that govern noncovalent interactions at the nanoscale.

  13. Van der Waals metal-semiconductor junction: Weak Fermi level pinning enables effective tuning of Schottky barrier

    DOE PAGES

    Liu, Yuanyue; Stradins, Paul; Wei, Su -Huai

    2016-04-22

    Two-dimensional (2D) semiconductors have shown great potential for electronic and optoelectronic applications. However, their development is limited by a large Schottky barrier (SB) at the metal-semiconductor junction (MSJ), which is difficult to tune by using conventional metals because of the effect of strong Fermi level pinning (FLP). We show that this problem can be overcome by using 2D metals, which are bounded with 2D semiconductors through van der Waals (vdW) interactions. This success relies on a weak FLP at the vdW MSJ, which is attributed to the suppression of metal-induced gap states. Consequently, the SB becomes tunable and can vanishmore » with proper 2D metals (for example, H-NbS2). This work not only offers new insights into the fundamental properties of heterojunctions but also uncovers the great potential of 2D metals for device applications.« less

  14. Varroa destructor changes its cuticular hydrocarbons to mimic new hosts

    PubMed Central

    Le Conte, Y.; Huang, Z. Y.; Roux, M.; Zeng, Z. J.; Christidès, J.-P.; Bagnères, A.-G.

    2015-01-01

    Varroa destructor (Vd) is a honeybee ectoparasite. Its original host is the Asian honeybee, Apis cerana, but it has also become a severe, global threat to the European honeybee, Apis mellifera. Previous studies have shown that Varroa can mimic a host's cuticular hydrocarbons (HC), enabling the parasite to escape the hygienic behaviour of the host honeybees. By transferring mites between the two honeybee species, we further demonstrate that Vd is able to mimic the cuticular HC of a novel host species when artificially transferred to this new host. Mites originally from A. cerana are more efficient than mites from A. mellifera in mimicking HC of both A. cerana and A. mellifera. This remarkable adaptability may explain their relatively recent host-shift from A. cerana to A. mellifera. PMID:26041867

  15. Multiscale simulation of pollution gases adsorption in porous organic cage CC3.

    PubMed

    Li, Wenliang; Zhang, Jingping

    2014-01-15

    A general multiscale simulation procedure is proposed to accurately predict the uptakes of pollution gases such as CO2, SO2, H2S, and CO in one of the most investigated porous organic cages CC3 by using a sophisticated force field vdW3 fitted by double hybrid functional (B2PLYP) with a dispersion correction (D3) separately for gas-gas and CC3-gas interactions. The fitted vdW3 was used in grand canonical Monte Carlo simulations. Good comparison with the coupled cluster single and double excitation and the perturbative triples (CCSD(T))/complete basis set (CBS) limit interaction energies make the B2PLYP-D3 results reliable for our purpose. The good agreement of simulated CO2 loading with experimental one and the low deviation in the fitting procedure for H2S and CO make our approach available in predicting gases in novel porous materials.

  16. Effect of van der Waals interactions on the chemisorption and physisorption of phenol and phenoxy on metal surfaces

    NASA Astrophysics Data System (ADS)

    Peköz, Rengin; Donadio, Davide

    2016-09-01

    The adsorption of phenol and phenoxy on the (111) surface of Au and Pt has been investigated by density functional theory calculations with the conventional PBE functional and three different non-local van der Waals (vdW) exchange and correlation functionals. It is found that both phenol and phenoxy on Au(111) are physisorbed. In contrast, phenol on Pt(111) presents an adsorption energy profile with a stable chemisorption state and a weakly metastable physisorbed precursor. While the use of vdW functionals is essential to determine the correct binding energy of both chemisorption and physisorption states, the relative stability and existence of an energy barrier between them depend on the semi-local approximations in the functionals. The first dissociation mechanism of phenol, yielding phenoxy and atomic hydrogen, has been also investigated, and the reaction and activation energies of the resulting phenoxy on the flat surfaces of Au and Pt were discussed.

  17. A DFT study of methanol dehydrogenation on the PdIn(110) surface.

    PubMed

    Ye, Jingyun; Liu, Changjun; Ge, Qingfeng

    2012-12-28

    Methanol decomposition to CO and H(2) on PdIn(110) has been studied by following the sequential dehydrogenation steps from CH(3)OH → CH(3)O → CH(2)O → CHO → CO using density functional theory slab calculations. The first three of the four elementary steps are strongly endothermic. The last step, i.e., CHO → CO + H, is almost thermal neutral. We also examined the effect of considering van der Waals interaction on the reaction energy and activation barrier of each elementary step by using the optB88-vdW and optB86b-vdW functionals. Our results show that both overall reaction energy and activation barrier were reduced by including van der Waals interactions but the qualitative picture remains unchanged. PMID:23069911

  18. Wavelike charge density fluctuations and van der Waals interactions at the nanoscale.

    PubMed

    Ambrosetti, Alberto; Ferri, Nicola; DiStasio, Robert A; Tkatchenko, Alexandre

    2016-03-11

    Recent experiments on noncovalent interactions at the nanoscale have challenged the basic assumptions of commonly used particle- or fragment-based models for describing van der Waals (vdW) or dispersion forces. We demonstrate that a qualitatively correct description of the vdW interactions between polarizable nanostructures over a wide range of finite distances can only be attained by accounting for the wavelike nature of charge density fluctuations. By considering a diverse set of materials and biological systems with markedly different dimensionalities, topologies, and polarizabilities, we find a visible enhancement in the nonlocality of the charge density response in the range of 10 to 20 nanometers. These collective wavelike fluctuations are responsible for the emergence of nontrivial modifications of the power laws that govern noncovalent interactions at the nanoscale. PMID:26965622

  19. Peptide Conformational Preferences in Osmolyte Solutions: Transfer Free Energies of Decaalanine

    SciTech Connect

    Kokubo, Hironori; Hu, Char Y.; Pettitt, Bernard M.

    2011-02-16

    The nature in which the protecting osmolyte trimethylamine N-oxide (TMAO) and the denaturing osmolyte urea affect protein stability is investigated, simulating a decaalanine peptide model in multiple conformations of the denatured ensemble. Binary solutions of both osmolytes and mixed osmolyte solutions at physiologically relevant concentrations of 2:1 (urea:TMAO) are studied using standard molecular dynamics simulations and solvation free energy calculations. Component analysis reveals the differences in the importance of the van der Waals (vdW) and electrostatic interactions for protecting and denaturing osmolytes. We find that urea denaturation governed by transfer free energy differences is dominated by vdW attractions, whereas TMAO exerts its effect by causing unfavorable electrostatic interactions both in the binary solution and mixed osmolyte solution. Analysis of the results showed no evidence in the ternary solution of disruption of the correlations among the peptide and osmolytes, nor of significant changes in the strength of the water hydrogen bond network.

  20. Photocurrent measurements in Coupled Quantum Well van der Waals Heterostructures made of 2D Transition Metal Dichalcogenides

    NASA Astrophysics Data System (ADS)

    Joe, Andrew; Jauregui, Luis; High, Alex; Dibos, Alan; Gulpinar, Elgin; Pistunova, Kateryna; Park, Hongkun; Kim, Philip

    , Luis A. Jauregui, Alex A. High, Alan Dibos, Elgin Gulpinar, Kateryna Pistunova, Hongkun Park, Philip Kim Harvard University, Physics Department -abstract- Single layer transition metal dichalcogenides (TMDC) are 2-dimensional (2D) semiconductors van der Waals (vdW) characterized by a direct optical bandgap in the visible wavelength (~2 eV). Characterization of the band alignment between TMDC and the barrier is important for the fabrication of tunneling devices. Here, we fabricate coupled quantum well (CQW) heterostructures made of 2D TMDCs with hexagonal Boron nitride (hBN) as an atomically thin barrier and gate dielectric and with top and bottom metal (or graphite) as gate electrodes. We observe a clear dependence of the photo-generated current with varying hBN thickness, electrode workfunctions, electric field, laser excitation power, excitation wavelength, and temperature. We will discuss the implication of photocurrent in relation to quantum transport process across the vdW interfaces.

  1. Quasiclassical trajectory study of the C(¹D) + H₂ → CH + H reaction on a new global ab initio potential energy surface.

    PubMed

    Wu, Ying; Zhang, Chunfang; Cao, Jianwei; Bian, Wensheng

    2014-06-19

    Quasiclassical trajectory (QCT) calculations have been performed on a new global ab initio potential energy surface (PES) for the singlet ground state (1(1)A') of the CH2 reactive system. Our new PES can give a very good description of the well and asymptote regions, and particularly regions around conical intersections (CIs) and of van der Waals (vdW) interactions. The integral cross sections, differential cross sections, and product rovibrational state distributions for the C((1)D) + H2 → CH + H reaction have been investigated in a wide range of collision energies. The present integral cross sections are much larger than the previous QCT results at low collision energies, which can be attributed to the differences of the PESs in the regions around the CIs and vdW complexes. The thermal rate coefficients in the temperature range 200-1500 K have also been calculated and very good agreement with experiment is obtained. PMID:24878310

  2. Range-separated approach to the RPA correlation applied to the van der Waals Bond and to diffusion of defects.

    PubMed

    Bruneval, Fabien

    2012-06-22

    The random-phase approximation (RPA) is a promising approximation to the exchange-correlation energy of density functional theory, since it contains the van der Waals (vdW) interaction and yields a potential with the correct band gap. However, its calculation is computationally very demanding. We apply a range-separation concept to RPA and demonstrate how it drastically speeds up the calculations without loss of accuracy. The scheme is then successfully applied to a layered system subjected to weak vdW attraction and is used to address the controversy of the self-diffusion in silicon. We calculate the formation and migration energies of self-interstitials and vacancies taking into account atomic relaxations. The obtained activation energies deviate significantly from the earlier calculations and challenge some of the experimental interpretations: the diffusion of vacancies and interstitials has almost the same activation energy.

  3. Varroa destructor changes its cuticular hydrocarbons to mimic new hosts.

    PubMed

    Le Conte, Y; Huang, Z Y; Roux, M; Zeng, Z J; Christidès, J-P; Bagnères, A-G

    2015-06-01

    Varroa destructor (Vd) is a honeybee ectoparasite. Its original host is the Asian honeybee, Apis cerana, but it has also become a severe, global threat to the European honeybee, Apis mellifera. Previous studies have shown that Varroa can mimic a host's cuticular hydrocarbons (HC), enabling the parasite to escape the hygienic behaviour of the host honeybees. By transferring mites between the two honeybee species, we further demonstrate that Vd is able to mimic the cuticular HC of a novel host species when artificially transferred to this new host. Mites originally from A. cerana are more efficient than mites from A. mellifera in mimicking HC of both A. cerana and A. mellifera. This remarkable adaptability may explain their relatively recent host-shift from A. cerana to A. mellifera.

  4. Vacuum distillation/vapor filtration water recovery, phases 1 and 2

    NASA Technical Reports Server (NTRS)

    Honegger, R. J.; Remus, G. A.; Krug, E. K.

    1973-01-01

    The research is reported on the development of an evaporator for vacuum distillation/vapor filtration VD/VF water reclamation system for use on manned space flights. The design, fabrication, and tests of a six-man evaporator are described. It is concluded that: (1) A condenser with an internal rotating impeller and coolant surfaces directly opposite the condensing surfaces is an effective condenser. (2) The VD/VF evaporator, catalyst unit and condenser function satisfactorily based on thermal, mechanical and recovery performance during a 145-hour evaluation test. (3) The quality of recovered water, as measured by analyses for total organic carbon, pH, conductivity, turbidity, and viable bacteria density was within established limits for potability.

  5. A crossover in anisotropic nanomechanochemistry of van der Waals crystals

    NASA Astrophysics Data System (ADS)

    Shimamura, Kohei; Misawa, Masaaki; Li, Ying; Kalia, Rajiv K.; Nakano, Aiichiro; Shimojo, Fuyuki; Vashishta, Priya

    2015-12-01

    In nanoscale mechanochemistry, mechanical forces selectively break covalent bonds to essentially control chemical reactions. An archetype is anisotropic detonation of layered energetic molecular crystals bonded by van der Waals (vdW) interactions. Here, quantum molecular dynamics simulations reveal a crossover of anisotropic nanomechanochemistry of vdW crystal. Within 10-13 s from the passage of shock front, lateral collision produces NO2 via twisting and bending of nitro-groups and the resulting inverse Jahn-Teller effect, which is mediated by strong intra-layer hydrogen bonds. Subsequently, as we transition from heterogeneous to homogeneous mechanochemical regimes around 10-12 s, shock normal to multilayers becomes more reactive, producing H2O assisted by inter-layer N-N bond formation. These time-resolved results provide much needed atomistic understanding of nanomechanochemistry that underlies a wider range of technologies.

  6. Tunable electronic properties of GeSe/phosphorene heterostructure from first-principles study

    NASA Astrophysics Data System (ADS)

    Yu, Weiyang; Zhu, Zhili; Zhang, Shengli; Cai, Xiaolin; Wang, Xiangfu; Niu, Chun-Yao; Zhang, Wei-Bing

    2016-09-01

    Vertical integration of two-dimensional materials has recently emerged as an exciting method for the design of electronic and optoelectronic devices. In this letter, first principles calculations are employed to explore the structural and electronic properties of the GeSe/phosphorene van der Waals (vdW) p-n heterostructure. Our results suggest that this heterostructure has an intrinsic type-II band alignment and indirect band gap. Moreover, we also find that an intriguing indirect-direct and insulator-metal transition can be induced by strain. In addition, spontaneous electron-hole charge separation is expected to occur, implying that the GeSe/phosphorene heterostructure is a good candidate for applications in optoelectronics. These results provide a route for applications of the GeSe/phosphorene vdW heterostructure in future flexible electronics, optoelectronics, and semiconductor devices.

  7. Oxygen-assisted excitation of methyl iodide as a test of double spin-flip transition in van der Waals complex CH3I-O2

    NASA Astrophysics Data System (ADS)

    Bogomolov, Alexandr S.; Kochubei, Sergei A.; Baklanov, Alexey V.

    2016-09-01

    Photoexcitation of van der Waals (vdW) complex CH3I-O2 has been studied with velocity map imaging of I atoms arising in photodissociation. A new scheme of resonance-enhanced multiphoton ionization of iodine atoms has been applied with simultaneous use of UV and VIS radiation. The measured kinetic energy of I(2P3/2) atoms indicates photogeneration of precursor CH3I molecules via complex-specific channel with excitation energy expected for double spin-flip transition in complex CH3I-O2. The angular distribution for recoil directions of I(2P3/2) atoms coming from vdW complexes also corresponds to that expected for double spin-flip transition.

  8. Causes of Vitamin D Deficiency and Effect of Vitamin D Supplementation on Metabolic Complications in Obesity: a Review.

    PubMed

    Wamberg, Louise; Pedersen, Steen B; Rejnmark, Lars; Richelsen, Bjørn

    2015-12-01

    Obese subjects are often characterized by low plasma 25-hydroxy-vitamin D (25OHD) levels. Many explanations for this association have been proposed. Low plasma 25OHD is associated with obesity-related comorbidities such as insulin resistance, type 2 diabetes mellitus, and low-grade inflammation. In this review, we discuss the proposed mechanisms for low 25OHD in obesity and explore the results of recent RCTs on vitamin D (VD) supplementation on obesity and its metabolic complications such as insulin resistance and type 2 diabetes. Although the results from these clinical randomized controlled trials vary, the general picture is that VD treatment of obese individuals does not seem to be an effective treatment of obesity-related metabolic complications.

  9. Dynamics of a delayed van der Pol-Mathieu oscillator

    NASA Astrophysics Data System (ADS)

    Sarmah, Dipak; Bora, Madhurjya P.

    2014-02-01

    The dynamics of a van der Pol-Mathieu (vdPM) equation with time delay is considered. The vdPM model can be realized as the governing equation for dust density in a simplified model of dusty plasma. The dynamics of the time-delayed equation is analyzed by separating the time-scales of the system assuming that the fundamental simple harmonic oscillator is at least an ϐ(ɛ) dominating other terms of the oscillator including time-delay, where ɛ ≪ 1. Our analytic prediction of the slow-flow system correctly represents the dynamics of the original system, showing periodic creation and annihilation of multi-periodic limit cycles. The original system is then analyzed using the DDE-Biftool [1] bifurcation analysis tool. We show that for large time-delay, the system undergoes a double-Hopf bifurcation, whereas for small delay, it undergoes a Bogdanov-Takens bifurcation.

  10. Van der Waals interaction-tuned heat transfer in nanostructures.

    PubMed

    Sun, Tao; Wang, Jianxiang; Kang, Wei

    2013-01-01

    Interfaces usually impede heat transfer in heterogeneous structures. Recent experiments show that van der Waals (vdW) interactions can significantly enhance thermal conductivity parallel to the interface of a bundle of nanoribbons compared to a single layer of freestanding nanoribbon. In this paper, by simulating heat transfer in nanostructures based on a model of nonlinear one-dimensional lattices interacting via van der Waals interactions, we show that the vdW interface interaction can adjust the thermal conductivity parallel to the interface. The efficiency of the adjustment depends on the intensity of interactions and temperature. The nonlinear dependence of the conductivity on the intensity of interactions agrees well with experimental results for carbon nanotube bundles, multi-walled carbon nanotubes, multi-layer graphene, and nanoribbons.

  11. Vibrational and Thermal Properties of β-HMX and TATB from Dispersion Corrected Density Functional Theory

    NASA Astrophysics Data System (ADS)

    Landerville, Aaron; Oleynik, Ivan

    2015-06-01

    Dispersion Corrected Density Functional Theory (DFT+vdW) calculations are performed to predict vibrational and thermal properties of the bulk energetic materials (EMs) β-octahydrocyclotetramethylene-tetranitramine (β-HMX) and triaminotrinitrobenzene (TATB). DFT+vdW calculations of optimized unit cells along the hydrostatic equation of state are followed by frozen-phonon calculations of their respective vibration spectra. These are then used under the quasi-harmonic approximation to obtain zero-point and thermal free energy contributions to the pressure, resulting in PVT equations of state for each material that is in excellent agreement with experiment. Further, heat capacities, thermal expansion coefficients, and Gruneissen parameters as functions of temperature are calculated and compared with experiment. The vibrational properties, including phonon densities of states and pressure dependencies of individual modes, are also analyzed and compared with experiment.

  12. Radiation Dose-Volume Effects in the Stomach and Small Bowel

    SciTech Connect

    Kavanagh, Brian D.; Pan, Charlie C.; Dawson, Laura A.; Das, Shiva K.; Li, X. Allen; Ten Haken, Randall K.; Miften, Moyed

    2010-03-01

    Published data suggest that the risk of moderately severe (>=Grade 3) radiation-induced acute small-bowel toxicity can be predicted with a threshold model whereby for a given dose level, D, if the volume receiving that dose or greater (VD) exceeds a threshold quantity, the risk of toxicity escalates. Estimates of VD depend on the means of structure segmenting (e.g., V15 = 120 cc if individual bowel loops are outlined or V45 = 195 cc if entire peritoneal potential space of bowel is outlined). A similar predictive model of acute toxicity is not available for stomach. Late small-bowel/stomach toxicity is likely related to maximum dose and/or volume threshold parameters qualitatively similar to those related to acute toxicity risk. Concurrent chemotherapy has been associated with a higher risk of acute toxicity, and a history of abdominal surgery has been associated with a higher risk of late toxicity.

  13. First-principles study for the adsorption of segments of BPA-PC on α-Al2O3(0001)

    NASA Astrophysics Data System (ADS)

    Blomqvist, Janne; Salo, Petri

    2011-10-01

    We have studied the adsorption of bisphenol-A-polycarbonate (BPA-PC) on the α-Al2O3(0001) surface using density functional theory (DFT) with van der Waals (vdW) corrections. The BPA-PC polymer can be divided into its chemical fragments, which are phenylene, carbonate, and isopropylidene groups. We have calculated the adsorption energy and geometry of the BPA-PC segments that consist of two to three adjacent groups of the polymer. Our DFT results show that the adsorption is dominated by the vdW interaction. It is also important to include the interaction of nearest-neighbor groups in order to provide a realistic environment for the adsorption of the polymer onto the surface. Our results also show that the BPA-PC molecule attaches to the alumina surface via the carbonate group located in the middle of the molecule chain.

  14. Formation of dimers of light noble atoms under encapsulation within fullerene's voids.

    PubMed

    Nikolaienko, Tymofii Yu; Kryachko, Eugene S

    2015-01-01

    Van der Waals (vdW) He2 diatomic trapped inside buckminsterfullerene's void and preserving its diatomic bonding is itself a controversial phenomenon due to the smallness of the void diameter comparing to the He-He equilibrium distance. We propound a computational approach, including smaller fullerenes, C20 and C28, to demonstrate that encapsulation of He2 inside the studied fullerenes exhibits an interesting quantum behavior resulting in a binding at shorter, non-vdW internuclear distances, and we develop a computational model to interpret these He-He bonding patterns in terms of Bader's atom-in-molecule theory. We also conjecture a computational existence of He2@C60 on a solid basis of its theoretical UV absorption spectrum and a comparison with that of C60. PMID:25983673

  15. A crossover in anisotropic nanomechanochemistry of van der Waals crystals

    SciTech Connect

    Shimamura, Kohei; Misawa, Masaaki; Li, Ying; Kalia, Rajiv K.; Nakano, Aiichiro; Vashishta, Priya; Shimojo, Fuyuki

    2015-12-07

    In nanoscale mechanochemistry, mechanical forces selectively break covalent bonds to essentially control chemical reactions. An archetype is anisotropic detonation of layered energetic molecular crystals bonded by van der Waals (vdW) interactions. Here, quantum molecular dynamics simulations reveal a crossover of anisotropic nanomechanochemistry of vdW crystal. Within 10{sup −13} s from the passage of shock front, lateral collision produces NO{sub 2} via twisting and bending of nitro-groups and the resulting inverse Jahn-Teller effect, which is mediated by strong intra-layer hydrogen bonds. Subsequently, as we transition from heterogeneous to homogeneous mechanochemical regimes around 10{sup −12} s, shock normal to multilayers becomes more reactive, producing H{sub 2}O assisted by inter-layer N-N bond formation. These time-resolved results provide much needed atomistic understanding of nanomechanochemistry that underlies a wider range of technologies.

  16. Nonlocal van der Waals functionals: the case of rare-gas dimers and solids.

    PubMed

    Tran, Fabien; Hutter, Jürg

    2013-05-28

    Recently, the nonlocal van der Waals (vdW) density functionals [M. Dion, H. Rydberg, E. Schröder, D. C. Langreth, and B. I. Lundqvist, Phys. Rev. Lett. 92, 246401 (2004)] have attracted considerable attention due to their good performance for systems where weak interactions are important. Since the physics of dispersion is included in these functionals, they are usually more accurate and show less erratic behavior than the semilocal and hybrid methods. In this work, several variants of the vdW functionals have been tested on rare-gas dimers (from He2 to Kr2) and solids (Ne, Ar, and Kr) and their accuracy compared to standard semilocal approximations, supplemented or not by an atom-pairwise dispersion correction [S. Grimme, J. Antony, S. Ehrlich, and H. Krieg, J. Chem. Phys. 132, 154104 (2010)]. An analysis of the results in terms of energy decomposition is also provided.

  17. Quasiclassical trajectory study of the C(¹D) + H₂ → CH + H reaction on a new global ab initio potential energy surface.

    PubMed

    Wu, Ying; Zhang, Chunfang; Cao, Jianwei; Bian, Wensheng

    2014-06-19

    Quasiclassical trajectory (QCT) calculations have been performed on a new global ab initio potential energy surface (PES) for the singlet ground state (1(1)A') of the CH2 reactive system. Our new PES can give a very good description of the well and asymptote regions, and particularly regions around conical intersections (CIs) and of van der Waals (vdW) interactions. The integral cross sections, differential cross sections, and product rovibrational state distributions for the C((1)D) + H2 → CH + H reaction have been investigated in a wide range of collision energies. The present integral cross sections are much larger than the previous QCT results at low collision energies, which can be attributed to the differences of the PESs in the regions around the CIs and vdW complexes. The thermal rate coefficients in the temperature range 200-1500 K have also been calculated and very good agreement with experiment is obtained.

  18. Room-temperature ferroelectricity in CuInP2S6 ultrathin flakes

    PubMed Central

    Liu, Fucai; You, Lu; Seyler, Kyle L.; Li, Xiaobao; Yu, Peng; Lin, Junhao; Wang, Xuewen; Zhou, Jiadong; Wang, Hong; He, Haiyong; Pantelides, Sokrates T.; Zhou, Wu; Sharma, Pradeep; Xu, Xiaodong; Ajayan, Pulickel M.; Wang, Junling; Liu, Zheng

    2016-01-01

    Two-dimensional (2D) materials have emerged as promising candidates for various optoelectronic applications based on their diverse electronic properties, ranging from insulating to superconducting. However, cooperative phenomena such as ferroelectricity in the 2D limit have not been well explored. Here, we report room-temperature ferroelectricity in 2D CuInP2S6 (CIPS) with a transition temperature of ∼320 K. Switchable polarization is observed in thin CIPS of ∼4 nm. To demonstrate the potential of this 2D ferroelectric material, we prepare a van der Waals (vdW) ferroelectric diode formed by CIPS/Si heterostructure, which shows good memory behaviour with on/off ratio of ∼100. The addition of ferroelectricity to the 2D family opens up possibilities for numerous novel applications, including sensors, actuators, non-volatile memory devices, and various vdW heterostructures based on 2D ferroelectricity. PMID:27510418

  19. Benzene on Cu(111): I. Application of van der Waals-Density Functional Formalism to Determine Binding Sites and Energy Contour Map

    NASA Astrophysics Data System (ADS)

    Berland, Kristian; Einstein, T. L.; Hyldgaard, Per

    2010-03-01

    With a recently developed van der Waals density functional (vdW-DF)footnotetextM. Dion et al., Phys. Rev. Lett. 92 (2004) 246401 we study the adsorption of benzene on Cu(111).footnotetextKB, TLE, and PH, Phys. Rev. B 80 (2009) 155431 The vdW-DF inclusion of nonlocal correlations changes the relative stability of 8 high-symmetry binding-position options and increases the adsorption energy by over an order of magnitude, achieving good agreement with experiment. The metallic surface state survives benzene adsorption. From a contour plot of the potential energy, we find that benzene can move almost freely along a honeycomb web of ``corridors" linking fcc and hcp sites via bridge sites, consistent with the low diffusion barrier in experiment.

  20. Interlayer electronic hybridization leads to exceptional thickness-dependent vibrational properties in few-layer black phosphorus

    NASA Astrophysics Data System (ADS)

    Hu, Zhi-Xin; Kong, Xianghua; Qiao, Jingsi; Normand, Bruce; Ji, Wei

    2016-01-01

    Stacking two-dimensional (2D) materials into multi-layers or heterostructures, known as van der Waals (vdW) epitaxy, is an essential degree of freedom for tuning their properties on demand. Few-layer black phosphorus (FLBP), a material with high potential for nano- and optoelectronics applications, appears to have interlayer couplings much stronger than graphene and other 2D systems. Indeed, these couplings call into question whether the stacking of FLBP can be governed only by vdW interactions, which is of crucial importance for epitaxy and property refinement. Here, we perform a theoretical investigation of the vibrational properties of FLBP, which reflect directly its interlayer coupling, by discussing six Raman-observable phonons, including three optical, one breathing and two shear modes. With increasing sample thickness, we find anomalous redshifts of the frequencies for each optical mode but a blueshift for the armchair shear mode. Our calculations also show splitting of the phonon branches, due to anomalous surface phenomena, and strong phonon-phonon coupling. By computing uniaxial stress effects, inter-atomic force constants and electron densities, we provide a compelling demonstration that these properties are the consequence of strong and highly directional interlayer interactions arising from the electronic hybridization of the lone electron-pairs of FLBP, rather than from vdW interactions. This exceptional interlayer coupling mechanism controls the stacking stability of BP layers and thus opens a new avenue beyond vdW epitaxy for understanding the design of 2D heterostructures.Stacking two-dimensional (2D) materials into multi-layers or heterostructures, known as van der Waals (vdW) epitaxy, is an essential degree of freedom for tuning their properties on demand. Few-layer black phosphorus (FLBP), a material with high potential for nano- and optoelectronics applications, appears to have interlayer couplings much stronger than graphene and other 2D

  1. van der Waals binding and band structure effects in graphene overlayers and graphane multilayers

    NASA Astrophysics Data System (ADS)

    Hyldgaard, Per; Rohrer, Jochen

    2011-03-01

    We study graphene formation (by selective Si evaporation) and adhesion on SiC surfaces as well as stacking and binding of graphane multilayers using a number of versions of the van der Waals Density Functional (vdW-DF) method and plane-wave density functional theory calculations. For the graphene/SiC systems and for the graphane multilayers we document that the bonding is entirely dominated by van der Waals (vdW) forces. At the same time we find that dispersive forces acting on the layers produce significant modifications in the graphene and graphane band structure. We interpret the changes and discuss a competition between wave function hybridization and interaction with the charge enhancement (between the layers) that results from density overlap. Supported by Svenska Vetenskapsrådet VR #621-2008-4346.

  2. Van der Waals metal-semiconductor junction: Weak Fermi level pinning enables effective tuning of Schottky barrier

    PubMed Central

    Liu, Yuanyue; Stradins, Paul; Wei, Su-Huai

    2016-01-01

    Two-dimensional (2D) semiconductors have shown great potential for electronic and optoelectronic applications. However, their development is limited by a large Schottky barrier (SB) at the metal-semiconductor junction (MSJ), which is difficult to tune by using conventional metals because of the effect of strong Fermi level pinning (FLP). We show that this problem can be overcome by using 2D metals, which are bounded with 2D semiconductors through van der Waals (vdW) interactions. This success relies on a weak FLP at the vdW MSJ, which is attributed to the suppression of metal-induced gap states. Consequently, the SB becomes tunable and can vanish with proper 2D metals (for example, H-NbS2). This work not only offers new insights into the fundamental properties of heterojunctions but also uncovers the great potential of 2D metals for device applications. PMID:27152360

  3. Radial Corrugations of Multi-Walled Carbon Nanotubes Driven by Inter-Wall Nonbonding Interactions

    PubMed Central

    2011-01-01

    We perform large-scale quasi-continuum simulations to determine the stable cross-sectional configurations of free-standing multi-walled carbon nanotubes (MWCNTs). We show that at an inter-wall spacing larger than the equilibrium distance set by the inter-wall van der Waals (vdW) interactions, the initial circular cross-sections of the MWCNTs are transformed into symmetric polygonal shapes or asymmetric water-drop-like shapes. Our simulations also show that removing several innermost walls causes even more drastic cross-sectional polygonization of the MWCNTs. The predicted cross-sectional configurations agree with prior experimental observations. We attribute the radial corrugations to the compressive stresses induced by the excessive inter-wall vdW energy release of the MWCNTs. The stable cross-sectional configurations provide fundamental guidance to the design of single MWCNT-based devices and shed lights on the mechanical control of electrical properties. PMID:27502675

  4. Improving the accuracy of the nonlocal van der Waals density functional with minimal empiricism.

    PubMed

    Vydrov, Oleg A; Van Voorhis, Troy

    2009-03-14

    The nonlocal van der Waals density functional (vdW-DF) captures the essential physics of the dispersion interaction not only in the asymptotic regime but also for a general case of overlapping fragment densities. A balanced treatment of other energetic contributions, such as exchange, is crucial if we aim for accurate description of various properties of weakly bound systems. In this paper, the vdW-DF correlation functional is modified to make it better compatible with accurate exchange functionals. We suggest a slightly simplified construction of the nonlocal correlation, yielding more accurate asymptotic C(6) coefficients. We also derive a gradient correction, containing a parameter that can be adjusted to suit an exchange functional of choice. We devise a particularly apt combination of exchange and correlation terms, which satisfies many important constraints and performs well for our benchmark tests.

  5. Room-temperature ferroelectricity in CuInP2S6 ultrathin flakes.

    PubMed

    Liu, Fucai; You, Lu; Seyler, Kyle L; Li, Xiaobao; Yu, Peng; Lin, Junhao; Wang, Xuewen; Zhou, Jiadong; Wang, Hong; He, Haiyong; Pantelides, Sokrates T; Zhou, Wu; Sharma, Pradeep; Xu, Xiaodong; Ajayan, Pulickel M; Wang, Junling; Liu, Zheng

    2016-01-01

    Two-dimensional (2D) materials have emerged as promising candidates for various optoelectronic applications based on their diverse electronic properties, ranging from insulating to superconducting. However, cooperative phenomena such as ferroelectricity in the 2D limit have not been well explored. Here, we report room-temperature ferroelectricity in 2D CuInP2S6 (CIPS) with a transition temperature of ∼320 K. Switchable polarization is observed in thin CIPS of ∼4 nm. To demonstrate the potential of this 2D ferroelectric material, we prepare a van der Waals (vdW) ferroelectric diode formed by CIPS/Si heterostructure, which shows good memory behaviour with on/off ratio of ∼100. The addition of ferroelectricity to the 2D family opens up possibilities for numerous novel applications, including sensors, actuators, non-volatile memory devices, and various vdW heterostructures based on 2D ferroelectricity. PMID:27510418

  6. High pressure phase transition in group III nitrides compounds

    NASA Astrophysics Data System (ADS)

    Soni, Shubhangi; Verma, S.; Kaurav, Netram; Choudhary, K. K.

    2016-05-01

    Using an effective interionic interaction potential (EIOP), the pressure induced structural phase transformation from ZnS-type (B3) to NaCl-type (B1) structure in group III Post-Transition Metal Nitrides [TMN; TM=Ga and Tl] were investigated. The long range Coulomb, van der Waals (vdW) interaction and the short-range repulsive interaction upto second-neighbor ions within the Hafemeister and Flygare approach with modified ionic charge are properly incorporated in the EIOP. The vdW coefficients are computed following the Slater-Kirkwood variational method, as both the ions are polarizable. The estimated value of the phase transition pressure (Pt) and the magnitude of the discontinuity in volume at the transition pressure are consistent as compared to the reported data.

  7. Structural and vibrational properties of α-MoO3 from van der Waals corrected density functional theory calculations

    NASA Astrophysics Data System (ADS)

    Ding, Hong; Ray, Keith G.; Ozolins, Vidvuds; Asta, Mark

    2012-01-01

    Structural and vibrational properties of α-MoO3 are studied employing two recently proposed methodologies for incorporating van der Waals (vdW) contributions in density functional theory (DFT) based calculations. The DFT-D2 [S. Grimme, J. Comput. Chem.JCCHDD0192-865110.1002/jcc.20495 27, 1787 (2006)] and optB88 vdW-DFT [J. Klimeš , J. Phys.: Condens. MatterPRBMDO0953-898410.1088/0953-8984/22/2/022201 22, 022201 (2010)] methods are shown to give rise to increased accuracy in predicted lattice parameters, relative to conventional DFT methods. Calculated vibrational frequencies agree with measurements to within 5% and 10% for modes involving bonded and nonbonded interactions in this compound, respectively.

  8. Kinetics and bioavailability of two formulations of amiloride in man

    PubMed Central

    Smith, A. J.; Smith, R. N.

    1973-01-01

    1. Two formulations of [14C]-amiloride were compared in six oedema-free subjects in single-dose (20 mg) studies separated by a two-week interval. 2. Calculation of the elimination rate constant (Ke), half-life (T½) and apparent volume of distribution (Vd) from serum and urinary data showed no significant difference between the two formulations. The Vd values (350 to 380 litres) were greater than total body fluid volume suggesting extravascular sequestration of amiloride. 3. Serum and urinary amiloride levels were similar with both formulations. Pharmacokinetic parameters were similar to those of an earlier report based on one formulation. 4. The calculated amiloride concentration in the renal distal tubule (3 μM to 20 μM) was similar to, but higher than, reported in vitro concentrations of amiloride which reduced sodium transport in isolated membranes. PMID:4788208

  9. Room-temperature ferroelectricity in CuInP2S6 ultrathin flakes

    NASA Astrophysics Data System (ADS)

    Liu, Fucai; You, Lu; Seyler, Kyle L.; Li, Xiaobao; Yu, Peng; Lin, Junhao; Wang, Xuewen; Zhou, Jiadong; Wang, Hong; He, Haiyong; Pantelides, Sokrates T.; Zhou, Wu; Sharma, Pradeep; Xu, Xiaodong; Ajayan, Pulickel M.; Wang, Junling; Liu, Zheng

    2016-08-01

    Two-dimensional (2D) materials have emerged as promising candidates for various optoelectronic applications based on their diverse electronic properties, ranging from insulating to superconducting. However, cooperative phenomena such as ferroelectricity in the 2D limit have not been well explored. Here, we report room-temperature ferroelectricity in 2D CuInP2S6 (CIPS) with a transition temperature of ~320 K. Switchable polarization is observed in thin CIPS of ~4 nm. To demonstrate the potential of this 2D ferroelectric material, we prepare a van der Waals (vdW) ferroelectric diode formed by CIPS/Si heterostructure, which shows good memory behaviour with on/off ratio of ~100. The addition of ferroelectricity to the 2D family opens up possibilities for numerous novel applications, including sensors, actuators, non-volatile memory devices, and various vdW heterostructures based on 2D ferroelectricity.

  10. Effect of van der Waals interactions on the chemisorption and physisorption of phenol and phenoxy on metal surfaces.

    PubMed

    Peköz, Rengin; Donadio, Davide

    2016-09-14

    The adsorption of phenol and phenoxy on the (111) surface of Au and Pt has been investigated by density functional theory calculations with the conventional PBE functional and three different non-local van der Waals (vdW) exchange and correlation functionals. It is found that both phenol and phenoxy on Au(111) are physisorbed. In contrast, phenol on Pt(111) presents an adsorption energy profile with a stable chemisorption state and a weakly metastable physisorbed precursor. While the use of vdW functionals is essential to determine the correct binding energy of both chemisorption and physisorption states, the relative stability and existence of an energy barrier between them depend on the semi-local approximations in the functionals. The first dissociation mechanism of phenol, yielding phenoxy and atomic hydrogen, has been also investigated, and the reaction and activation energies of the resulting phenoxy on the flat surfaces of Au and Pt were discussed. PMID:27634269

  11. [Focus on risk assessment in health environments: results and perspectives of a multicenter working group].

    PubMed

    Polato, R; Bacis, M; Belotti, L; Biggi, N; Campagna, M; Carrer, P; Cologni, L; Gattini, V; Lodi, V; Magnavita, N; Micheloni, G; Negro, C; Placidi, D; Puro, V; Tonelli, F; Porru, S

    2010-01-01

    The hospital risk assessment (VdR) is certainly a relevant issue concerning the activities of prevention for the health of healthcare workers in relation to biological risk. The aim of this paper is to provide an up-date of the issue, based on the suggestions of recent literature about the rules ratified by the new legislative decree and data supplied by the Group of 10 Hospitals participated in this multicenter study. From the analysis of data on healthcare settings (HCS) participating in the project the following considerations can be formulated: i) All HCS considered VdR from biological agents. The method recommended in the Guidelines SIMLII 2005 is the most followed ii) To grading the risk, the use of invasive procedures for carrying out the analysis results is a necessary element iii) the operators classified as exposed to biological risk, and therefore subject to health surveillance, represent almost all of workforce in 7 out of 10 HCS. The subgroup believes that VdR must be conducted in close collaboration with the occupational physician and should represent a worthwhile investment with spin-off character on prevention, decision making, empowering. The presence of environmental requirements and organizational procedures should be considered, so that HCS is enabled for an effective risk management, without which risk assessments cannot be performed. The method of VdR mentioned in the guidelines MLIS 2005, besides being the most widely used by the company participating in the study, still has practical reasons and opportunities to justify its use. The HCS group felt the need to propose an implementation of the definition of invasive procedures and EPP, together with individual assessment. Flexibility was suggested in identifying different levels of risk with the involvement of occupational physicians, especially in the presence of EPP, also in order to plan content and frequency of health surveillance.

  12. The role of collective motion in the ultrafast charge transfer in van der Waals heterostructures

    DOE PAGES

    Wang, Han; Bang, Junhyeok; Sun, Yiyang; West, Damien; Meunier, Vincent; Zhang, Shengbai; Liang, Linagbo

    2016-05-10

    Here, the success of van der Waals (vdW) heterostructures, made of graphene, metal dichalcogenides, and other layered materials, hinges on the understanding of charge transfer across the interface as the foundation for new device concepts and applications. In contrast to conventional heterostructures, where a strong interfacial coupling is essential to charge transfer, recent experimental findings indicate that vdW heterostructues can exhibit ultra-fast charge transfer despite the weak binding of the heterostructure. Using time-dependent density functional theory molecular dynamics, we identify a strong dynamic coupling between the vdW layers associated with charge transfer. This dynamic coupling results in rapid nonlinear coherentmore » charge oscillations which constitute a purely electronic phenomenon and are shown to be a general feature of vdW heterostructures provided they have a critical minimum dipole coupling. Application to MoS2/WS2 heterostructure yields good agreement with experiment, indicating near complete charge transfer within a timescale of 100 fs.The success of van der Waals heterostructures made of graphene, metal dichalcogenides and other layered materials, hinges on the understanding of charge transfer across the interface as the foundation for new device concepts and applications. In contrast to conventional heterostructures, where a strong interfacial coupling is essential to charge transfer, recent experimental findings indicate that van der Waals heterostructues can exhibit ultrafast charge transfer despite the weak binding of these heterostructures. Here we find, using time-dependent density functional theory molecular dynamics, that the collective motion of excitons at the interface leads to plasma oscillations associated with optical excitation. By constructing a simple model of the van der Waals heterostructure, we show that there exists an unexpected criticality of the oscillations, yielding rapid charge transfer across the

  13. Ozone concentrations, flux and potential effect on yield during wheat growth in the Northwest-Shandong Plain of China.

    PubMed

    Zhu, Zhilin; Sun, Xiaomin; Zhao, Fenghua; Meixner, Franz X

    2015-08-01

    Ozone (O3) concentration and flux (Fo) were measured using the eddy covariance technique over a wheat field in the Northwest-Shandong Plain of China. The O3-induced wheat yield loss was estimated by utilizing O3 exposure-response models. The results showed that: (1) During the growing season (7 March to 7 June, 2012), the minimum (16.1 ppbV) and maximum (53.3 ppbV) mean O3 concentrations occurred at approximately 6:30 and 16:00, respectively. The mean and maximum of all measured O3 concentrations were 31.3 and 128.4 ppbV, respectively. The variation of O3 concentration was mainly affected by solar radiation and temperature. (2) The mean diurnal variation of deposition velocity (Vd) can be divided into four phases, and the maximum occurred at noon (12:00). Averaged Vd during daytime (6:00-18:00) and nighttime (18:00-6:00) were 0.42 and 0.14 cm/sec, respectively. The maximum of measured Vd was about 1.5 cm/sec. The magnitude of Vd was influenced by the wheat growing stage, and its variation was significantly correlated with both global radiation and friction velocity. (3) The maximum mean Fo appeared at 14:00, and the maximum measured Fo was -33.5 nmol/(m(2)·sec). Averaged Fo during daytime and nighttime were -6.9 and -1.5 nmol/(m(2)·sec), respectively. (4) Using O3 exposure-response functions obtained from the USA, Europe, and China, the O3-induced wheat yield reduction in the district was estimated as 12.9% on average (5.5%-23.3%). Large uncertainties were related to the statistical methods and environmental conditions involved in deriving the exposure-response functions.

  14. Objective Evaluation of Vergence Disorders and a Research-Based Novel Method for Vergence Rehabilitation

    PubMed Central

    Kapoula, Zoï; Morize, Aurélien; Daniel, François; Jonqua, Fabienne; Orssaud, Christophe; Brémond-Gignac, Dominique

    2016-01-01

    Purpose We performed video-oculography to evaluate vergence eye movement abnormalities in students diagnosed clinically with vergence disorders. We tested the efficiency of a novel rehabilitation method and evaluated its benefits with video-oculography cross-correlated with clinical tests and symptomatology. Methods A total of 19 students (20–27 years old) underwent ophthalmologic, orthoptic examination, and a vergence test coupled with video-oculography. Eight patients were diagnosed with vergence disorders with a high symptomatology score (CISS) and performed a 5-week session of vergence rehabilitation. Vergence and rehabilitation tasks were performed with a trapezoid surface of light emitting diodes (LEDs) and adjacent buzzers (US 8851669). We used a novel Vergence double-step (Vd-s) protocol: the target stepped to a second position before the vergence movement completion. Afterward the vergence test was repeated 1 week and 1 month later. Results Abnormally increased intertrial variability was observed for many vergence parameters (gain, duration, and speed) for the subjects with vergence disorders. High CISS scores were correlated with variability and increased latency. After the Vd-s, variability of all parameters dropped to normal or better levels. Moreover, the convergence and divergence latency diminished significantly to levels better than normal; benefits were maintained 1 month after completion of Vd-s. CISS scores dropped to normal level, which was maintained up to 1 year. Conclusions and Translational Relevance: Intertrial variability is the major marker of vergence disorders. The Vd-s research-based method leads to normalization of vergence properties and lasting removal of symptoms. The efficiency of the method is due to the spatiotemporal parameters of repetitive trials that stimulate neural plasticity. PMID:26981330

  15. Cesarean section increases the risk of respiratory adaptive disorders in healthy late preterm and two groups of mature newborns.

    PubMed

    Offermann, H; Gebauer, C; Pulzer, F; Bläser, A; Thome, U; Knüpfer, M

    2015-12-01

    The rates of delivery by Cesarean section (CS) have been trending upwards in recent decades, perhaps leading to higher rates of dysfunction in respiratory adaptation in newborns. We present epidemiological data for pulmonary adaptation by mode of delivery for healthy late preterm and term infants born at a regional tertiary care center. The overall CS rate was 22% with the largest proportion of these in late preterms (39%). This drops to 30% in infants born after 37 weeks gestation and to 11% for those born after 40 weeks. Infants needing respiratory support decreased significantly as gestational age increased: 88% at 34 weeks, 67% at 35 weeks, 28% at 36 weeks, 17% at 37 weeks and 8% at 40 weeks. The risk of respiratory morbidity following CS as compared to vaginal delivery (VD) was substantially higher. 50% of infants born by CS needed respiratory support compared to only 12% following VD. 82% of all late preterm infants born by CS developed respiratory morbidity compared to 36% following VD. Comparable data for infants born after 37 and 40 weeks gestation were 33% compared to 9% and 26% compared to 6% respectively. Late preterm infants born after 36 weeks gestation showed the most marked difference by mode of birth with 66% needing respiratory support following CS as compared to only 9% following VD. Our data could be useful in counselling parents about risk associated with delivery by Cesarean section. A critical view should be taken of increasing CS rates worldwide because of a clear correlation in increased morbidity in infants, especially late preterm infants.

  16. Mortality due to Cardiovascular Diseases in Women and Men in the Five Brazilian Regions, 1980-2012

    PubMed Central

    Mansur, Antonio de Padua; Favarato, Desidério

    2016-01-01

    Background: Studies have shown different mortalities due to cardiovascular diseases (CVD), ischemic heart disease (IHD) and cerebrovascular diseases (CbVD) in the five Brazilian regions. Socioeconomic conditions of those regions are frequently used to justify differences in mortality due to those diseases. In addition, studies have shown a reduction in the differences between the mortality rates of the five Brazilian regions. Objective: To update CVD mortality data in women and men in the five Brazilian regions. Methods: Mortality and population data were obtained from the Brazilian Institute of Geography and Statistics and Ministry of Health. Risk of death was adjusted by use of the direct method, with the 2000 world standard population as reference. We analyzed trends in mortality due to CVD, IHD and CbVD in women and men aged ≥ 30 years in the five Brazilian regions from 1980 to 2012. Results: Mortality due to: 1) CVD: showed reduction in the Northern, West-Central, Southern and Southeastern regions; increase in the Northeastern region; 2) IHD: reduction in the Southeastern and Southern regions; increase in the Northeastern region; and unchanged in the Northern and West-Central regions; 3) CbVD: reduction in the Southern, Southeastern and West-Central regions; increase in the Northeastern region; and unchanged in Northern region. There was also a convergence in mortality trends due to CVD, IHD, and CbVD in the five regions. Conclusion: The West-Central, Northern and Northeastern regions had the worst trends in CVD mortality as compared to the Southeastern and Southern regions. (Arq Bras Cardiol. 2016; [online].ahead print, PP.0-0) PMID:27437866

  17. Feasibility and impact of the measurement of extracellular fluid volume simultaneous with GFR by 125I-iothalamate.

    PubMed

    Visser, Folkert W; Muntinga, Jaap H J; Dierckx, Rudi A; Navis, Gerjan

    2008-09-01

    The feasibility, validity, and possible applications of the assessment of extracellular fluid volume (ECFV) simultaneous with glomerular filtration rate (GFR) were assessed in a series of validation studies using the constant infusion method of (125)I-iothalamate (IOT). In 48 subjects with a broad range of GFR, distribution volume (V(d)) of IOT corresponded well with V(d) bromide (16.71 +/- 3.0 and 16.73 +/- 3.2 l, respectively, not significant), with a strong correlation (r = 0.933, P < 0.01) and without systematic deviations. Reproducibility assessment in 25 healthy male subjects showed coefficients of variation of 8.6% of duplicate measurement of V(d) IOT during strictly standardized (50 mmol Na(+)/d) sodium intake. An increase in dietary sodium intake (200 mmol Na(+)/d) induced a corresponding rise in V(d) IOT of 1.11 +/- 1.5 l (P < 0.01). In 158 healthy prospective kidney donors, the impact of indexing of GFR to ECFV was analyzed. Age, gender, height, and body surface area (BSA) were determinants of GFR. Whereas GFR, GFR/BSA, and GFR/height were gender-dependent, GFR/ECFV was gender-independent and not related to height or BSA. This supports the potential of normalizing GFR by ECFV. Thus, ECFV can be simultaneously assessed with GFR by the constant infusion method using IOT. After appropriate validation, also other GFR tracers could be used for such a simultaneous estimation, providing a valuable resource of data on ECFV in renal studies and, moreover, allowing GFR to be indexed to the body fluid compartment it clears: the ECFV.

  18. Global analytical ab initio ground-state potential energy surface for the C((1)D)+H2 reactive system.

    PubMed

    Zhang, Chunfang; Fu, Mingkai; Shen, Zhitao; Ma, Haitao; Bian, Wensheng

    2014-06-21

    A new global ab initio potential energy surface (called ZMB-a) for the 1(1)A' state of the C((1)D)+H2 reactive system has been constructed. This is based upon ab initio calculations using the internally contracted multireference configuration interaction approach with the aug-cc-pVQZ basis set, performed at about 6300 symmetry unique geometries. Accurate analytical fits are generated using many-body expansions with the permutationally invariant polynomials, except that the fit of the deep well region is taken from our previous fit. The ZMB-a surface is unique in the accurate description of the regions around conical intersections (CIs) and of van der Waals (vdW) interactions. The CIs between the 1(1)A' and 2(1)A' states cause two kinds of barriers on the ZMB-a surface: one is in the linear H-CH dissociation direction with a barrier height of 9.07 kcal/mol, which is much higher than those on the surfaces reported before; the other is in the C((1)D) collinearly attacking H2 direction with a barrier height of 12.39 kcal/mol. The ZMB-a surface basically reproduces our ab initio calculations in the vdW interaction regions, and supports a linear C-HH vdW complex in the entrance channel, and two vdW complexes in the exit channel, at linear CH-H and HC-H geometries, respectively. PMID:24952535

  19. Impact of protective agents and drying methods on desiccation tolerance of Salix nigra L. seeds.

    PubMed

    Santagapita, Patricio R; Ott Schneider, Helena; Agudelo-Laverde, Lina M; Buera, M Pilar

    2014-09-01

    Willow seeds are classified as orthodox, but they show some recalcitrant characteristics, as they lose viability in a few weeks at room temperature. The aim of this work was to improve the desiccation tolerance of willow seeds (Salix nigra L.), as a model of sensitive materials to dehydration, through imbibition in solutions and later vacuum (VD) or freeze-drying (FD). Imbibition was conducted with 45% w/v trehalose or polyethylene glycol 400 -PEG- or water prior to dehydration treatments. Water- and especially trehalose-imbibed seeds subjected to VD showed better germination capability with respect to the freeze-dried ones. Water crystallization was mainly responsible for the great loss of capability germination observed in water- or trehalose-imbibed seeds subjected to FD. PEG behavior was better when seeds were FD instead of VD. DSC thermograms of seeds allowed to identify two thermal transitions corresponding to lipids melting and to proteins denaturation. This last transition reveals information about proteins state/functionality. Dehydration of control and PEG- or water-imbibed seeds affected proteins functionality leading to lower germinability. In the case of trehalose-imbibed seeds subjected to VD, proteins maintained their native state along dehydration, and the seeds showed a great germination capacity for all the water content range. Germinated seeds showed higher luminosity (L*), greenness (a*) and yellowness (b*) values than not-germinated seeds independently of the employed agent. Present work reveals that the presence of adequate protective agents as well the dehydration method were the main critical factors involved in willow seed desiccation tolerance. PMID:25016075

  20. Investigation of the range of validity of the pairwise summation method applied to the calculation of the surface roughness correction to the van der Waals force

    NASA Astrophysics Data System (ADS)

    Gusso, André; Burnham, Nancy A.

    2016-09-01

    It has long been recognized that stochastic surface roughness can considerably change the van der Waals (vdW) force between interacting surfaces and particles. However, few analytical expressions for the vdW force between rough surfaces have been presented in the literature. Because they have been derived using perturbative methods or the proximity force approximation the expressions are valid when the roughness correction is small and for a limited range of roughness parameters and surface separation. In this work, a nonperturbative approach, the effective density method (EDM) is proposed to circumvent some of these limitations. The method simplifies the calculations of the roughness correction based on pairwise summation (PWS), and allows us to derive simple expressions for the vdW force and energy between two semispaces covered with stochastic rough surfaces. Because the range of applicability of PWS and, therefore, of our results, are not known a priori, we compare the predictions based on the EDM with those based on the multilayer effective medium model, whose range of validity can be defined more properly and which is valid when the roughness correction is comparatively large. We conclude that the PWS can be used for roughness characterized by a correlation length of the order of its rms amplitude, when this amplitude is of the order of or smaller than a few nanometers, and only for typically insulating materials such as silicon dioxide, silicon nitride, diamond, and certain glasses, polymers and ceramics. The results are relevant for the correct modeling of systems where the vdW force can play a significant role such as micro and nanodevices, for the calculation of the tip-sample force in atomic force microscopy, and in problems involving adhesion.

  1. Dark-matter haloes and the M-σ relation for supermassive black holes

    NASA Astrophysics Data System (ADS)

    Larkin, Adam C.; McLaughlin, Dean E.

    2016-10-01

    We develop models of two-component spherical galaxies to establish scaling relations linking the properties of spheroids at z = 0 (total stellar masses, effective radii Re and velocity dispersions within Re) to the properties of their dark-matter haloes at both z = 0 and higher redshifts. Our main motivation is the widely accepted idea that the accretion-driven growth of supermassive black holes (SMBHs) in protogalaxies is limited by quasar-mode feedback and gas blow-out. The SMBH masses, MBH, should then be connected to the dark-matter potential wells at the redshift zqso of the blow-out. We specifically consider the example of a power-law dependence on the maximum circular speed in a protogalactic dark-matter halo: M_{BH}∝ V^4_{d,pk}, as could be expected if quasar-mode feedback were momentum-driven. For haloes with a given Vd,pk at a given zqso ≥ 0, our model scaling relations give a typical stellar velocity dispersion σap(Re) at z = 0. Thus, they transform a theoretical MBH-Vd,pk relation into a prediction for an observable MBH-σap(Re) relation. We find the latter to be distinctly non-linear in log-log space. Its shape depends on the generic redshift evolution of haloes in a Λ cold dark matter cosmology and the systematic variation of stellar-to-dark matter mass fraction at z = 0, in addition to any assumptions about the physics underlying the MBH-Vd,pk relation. Despite some clear limitations of the form we use for MBH versus Vd,pk, and even though we do not include any SMBH growth through dry mergers at low redshift, our results for MBH-σap(Re) compare well to data for local early types if we take zqso ˜ 2-4.

  2. Descendant root volume varies as a function of root type: estimation of root biomass lost during uprooting in Pinus pinaster.

    PubMed

    Danjon, Frédéric; Caplan, Joshua S; Fortin, Mathieu; Meredieu, Céline

    2013-01-01

    Root systems of woody plants generally display a strong relationship between the cross-sectional area or cross-sectional diameter (CSD) of a root and the dry weight of biomass (DWd) or root volume (Vd) that has grown (i.e., is descendent) from a point. Specification of this relationship allows one to quantify root architectural patterns and estimate the amount of material lost when root systems are extracted from the soil. However, specifications of this relationship generally do not account for the fact that root systems are comprised of multiple types of roots. We assessed whether the relationship between CSD and Vd varies as a function of root type. Additionally, we sought to identify a more accurate and time-efficient method for estimating missing root volume than is currently available. We used a database that described the 3D root architecture of Pinus pinaster root systems (5, 12, or 19 years) from a stand in southwest France. We determined the relationship between CSD and Vd for 10,000 root segments from intact root branches. Models were specified that did and did not account for root type. The relationships were then applied to the diameters of 11,000 broken root ends to estimate the volume of missing roots. CSD was nearly linearly related to the square root of Vd, but the slope of the curve varied greatly as a function of root type. Sinkers and deep roots tapered rapidly, as they were limited by available soil depth. Distal shallow roots tapered gradually, as they were less limited spatially. We estimated that younger trees lost an average of 17% of root volume when excavated, while older trees lost 4%. Missing volumes were smallest in the central parts of root systems and largest in distal shallow roots. The slopes of the curves for each root type are synthetic parameters that account for differentiation due to genetics, soil properties, or mechanical stimuli. Accounting for this differentiation is critical to estimating root loss accurately.

  3. Risk of Chronic Low Back Pain Among Parturients Who Undergo Cesarean Delivery With Neuraxial Anesthesia

    PubMed Central

    Chia, Yuan-Yi; Lo, Yuan; Chen, Yan-Bo; Liu, Chun-Peng; Huang, Wei-Chun; Wen, Chun-Hsien

    2016-01-01

    Abstract To investigate the risk of chronic low back pain (LBP) in parturients undergoing cesarean delivery (CD) with neuraxial anesthesia (NA). LBP is common during pregnancy and also after delivery, but its etiology is poorly understood. Previous studies that investigated the correlation between epidural labor analgesia and chronic low back pain were inconclusive. These studies lacked objective diagnostic criteria for LBP and did not exclude possible confounders. We performed this nationwide population-based retrospective cohort study to explore the relationship between CD with NA and subsequent LBP. From the Taiwan National Health Insurance Research Database (NHIRD), we identified all primiparas who had given birth between January 1, 2000 and December 31, 2013. Using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) procedure codes, we identified the women who had vaginal delivery (VD) and those who had CD. The mode of anesthesia was ascertained by the NHI codes. Multivariable logistic regression was used to estimate the odds of postpartum LBP in women undergoing CD with NA compared with those having VD. The outcome was a diagnosis of LBP according to the first ICD-9-CM diagnosis code. The patients were observed for 3 years after delivery or until diagnosis of postpartum LBP, withdrawal from the NHI system, death, or December 31, 2013. Of the 61,027 primiparas who underwent delivery during the observation period, 40,057 were eligible for inclusion in the study. Of these women, 27,097 (67.6%) received VD, 8662 (21.6%) received CD with spinal anesthesia, and 4298 (10.7%) received CD with epidural anesthesia (EA). Women who received CD with EA were found to have higher risk of LBP than did women who received VD, with the adjusted OR being 1.26 (95% CI: 1.17–1.34). CD with EA might increase the risk of subsequent chronic LBP. PMID:27100449

  4. MHD-model for low-frequency waves in a tokamak with toroidal plasma rotation and problem of existence of global geodesic acoustic modes

    SciTech Connect

    Lakhin, V. P.; Sorokina, E. A. E-mail: vilkiae@gmail.com; Ilgisonis, V. I.; Konovaltseva, L. V.

    2015-12-15

    A set of reduced linear equations for the description of low-frequency perturbations in toroidally rotating plasma in axisymmetric tokamak is derived in the framework of ideal magnetohydrodynamics. The model suitable for the study of global geodesic acoustic modes (GGAMs) is designed. An example of the use of the developed model for derivation of the integral conditions for GGAM existence and of the corresponding dispersion relation is presented. The paper is dedicated to the memory of academician V.D. Shafranov.

  5. The control region of maternally and paternally inherited mitochondrial genomes of three species of the sea mussel genus Mytilus.

    PubMed

    Cao, Liqin; Ort, Brian S; Mizi, Athanasia; Pogson, Grant; Kenchington, Elen; Zouros, Eleftherios; Rodakis, George C

    2009-03-01

    Species of the mussel genus Mytilus possess maternally and paternally transmitted mitochondrial genomes. In the interbreeding taxa Mytilus edulis and M. galloprovincialis, several genomes of both types have been fully sequenced. The genome consists of the coding part (which, in addition to protein and RNA genes, contains several small noncoding sequences) and the main control region (CR), which in turn consists of three distinct parts: the first variable (VD1), the conserved (CD), and the second variable (VD2) domain. The maternal and paternal genomes are very similar in gene content and organization, even though they differ by >20% in primary sequence. They differ even more at VD1 and VD2, yet they are remarkably similar at CD. The complete sequence of a genome from the closely related species M. trossulus was previously reported and found to consist of a maternal-like coding part and a paternal-like and a maternal-like CR. From this and from the fact that it was extracted from a male individual, it was inferred that this is a genome that switched from maternal to paternal transmission. Here we provide clear evidence that this genome is the maternal genome of M. trossulus. We have found that in this genome the tRNA(Gln) in the coding region is apparently defective and that an intact copy of this tRNA occurs in the CR, that one of the two conserved domains is missing essential motifs, and that one of the two first variable domains has a high rate of divergence. These features may explain the large size and mosaic structure of the CR of the maternal genome of M. trossulus. We have also obtained CR sequences of the maternal and paternal genomes of M. californianus, a more distantly related species. We compare the control regions from all three species, focusing on the divergence among genomes of different species origin and among genomes of different transmission routes.

  6. Vesicles from pH-regulated reversible gemini amino-acid surfactants as nanocapsules for delivery.

    PubMed

    Lv, Jing; Qiao, Weihong; Li, Zongshi

    2016-10-01

    Reversible transition from micelles to vesicles by regulating pH were realized by gemini amino-acid surfactants N,N'-dialkyl-N,N'-diacetate ethylenediamine. Measurement results of ζ-potential at different pH and DLS at varying solvents revealed that the protonation between H(+) and double NCH2COO(-) groups (generating NH(+)CH2COO(-)), expressed as pKa1 and pKa2, is the key driving force to control the aggregation behaviors of gemini surfactant molecule. Effect of pH on the bilayer structure was studied in detail by using steady-state fluorescence spectroscopy of hydrophobic pyrene and Coumarin 153 (C153) respectively and fluorescence resonance energy transfer (FRET) from C153 to Rhodamine 6G (R6G). Various pH-regulated and pH-reversible self-assemblies were obtained in one surfactant system. Vitamin D3 was encapsulated in vesicle bilayers to form nano-VD3-capsules as VD3 supplement agent for health care products. By using the electrostatic attraction between Ca(2+) and double -COO(-) groups, nano-VD3-capsules with Ca(2+) coated outermost layers were prepared as a formulation for VD3 and calcium co-supplement agent. DLS and TEM were performed to check stability and morphology of the nano-capsules. It is concluded that the pH-regulated gemini amino-acid surfactants can be used to construct colloidal systems for delivering hydrophobic drugs or nutritions without lipids at human physiological pH level. PMID:27419647

  7. The use of geographical information systems for disaster risk reduction strategies: a case study of Volcan de Colima, Mexico

    NASA Astrophysics Data System (ADS)

    Landeg, O.

    Contemporary disaster risk management requires the analysis of vulnerability and hazard exposure, which is imperative at Volcan de Colima (VdC), Mexico, due to the predicted, large-magnitude eruption forecast to occur before 2025. The methods used to gauge social vulnerability included the development and application of proxies to census records, the undertaking of a building vulnerability survey and the spatial mapping of civil and emergency infrastructure. Hazard exposure was assessed using primary modelling of laharic events and the digitalisation of secondary data sources detailing the modelled extent of pyroclastic flows and tephra deposition associated with a large-magnitude (VEI 5) eruption at VdC. The undertaking and analysis of a risk perception survey of the population enabled an understanding of the cognitive behaviour of residents towards the volcanic risk. In comparison to the published hazard map, the GIS analysis highlighted an underestimation of lahar hazard on the western flank of VdC and the regional tephra hazard. Vulnerability analysis identified three communities where social deprivation is relatively high, and those with significant elderly and transient populations near the volcano. Furthermore, recognition of the possibility of an eruption in the near future was found to be low across the study region. These results also contributed to the analysis of emergency management procedures and the preparedness of the regional authorities. This multidisciplinary research programme demonstrates the success of applying a GIS platform to varied integrative spatial and temporal analysis. Furthermore, ascertaining the impact of future activity at VdC upon its surrounding populations permits the evaluation of emergency preparedness and disaster risk reduction strategies.

  8. Molecular spin on surface: From strong correlation to dispersion interactions

    NASA Astrophysics Data System (ADS)

    Zhang, Yachao

    2016-09-01

    A reliable prediction of magnetic properties of surface-supported molecules containing 3d/4f spin carriers has challenged the electronic structure theory for decades. Here we tackle this problem with Hubbard-U corrected van der Waals density functional (vdW-DF), incorporating strong correlation effects of the localized electrons and dispersion interactions involved in the molecule-surface binding. By fitting the spin state energetics of a series of Fe(ii) compounds with varying ligand field strength, we find that the optimal U value for vdW-DF is much smaller than that for the local density approximation (LDA) while quite similar to that for the generalized gradient approximation (GGA). We show that although vdW-DF+U overestimates largely the metal-ligand bond distance, the predicted adiabatic high-spin-low-spin energy splitting ΔEHL is only slightly changed with respect to that obtained using the LDA+U geometries consistent with experiment. Then we use Cu(111)-supported metallocene (M(C5H5)2, M = Fe, and Co) as a prototype example to explore the effects of the molecule-surface interactions. We show that the non-local dispersion interactions, poorly described by LDA and GGA while reasonably captured by vdW-DF, are critical for reproducing ΔEHL at large molecule-surface distances. Besides, we find that ΔEHL is decreased by the molecule-metal contact, which is shown to weaken the local ligand field around the magnetic center.

  9. An extensive computational study of the adsorption of thiophene on transition metal surfaces: role of van der Waals

    NASA Astrophysics Data System (ADS)

    Rojas, Tomas; Kara, Abdelkader

    2014-03-01

    Van der Waals (vdWs) interactions play a significant role in the determination of the adsorption characteristics at the interface between a molecule and a substrate. In this study, self-consistent inclusion of vdW interactions in density functional theory provides a good perspective to understand the interaction between organic adsorbates and inorganic interfaces. We present the results of adsorption of thiophene (C4H4S) on various transition metal surfaces with the goal of comparing the performance of five different vdW functionals (optB86, optB88, optPBE, revPBE, rPW86). Seven metallic substrates (100) are used for our study; three coinage metals (Au, Ag, Cu) and four reactive metals (Pt, Pd, Rh, Ni). The results show that vdWs inclusion enhances the interaction for Ag (0.08 to 0.73 eV), Au (0.14 to 0.86 eV), Cu (0.12 eV to 0.77 eV), Ni(1.56 to 2.34 eV), Pt (1.6 to 2.51 eV), Pd (1.67 to 2.54), Rh (1.74 to 2.96 eV). In addition, we performed calculations for adsorption heights along with analysis of the electronic changes (charge transfer, changes in the d-band of the substrate, and change in the work function) to complement our understanding of these systems. This work is funded by the U.S. Department of Energy Basic Energy Science under Contract No DE-FG02-11ER16243.

  10. Relating left ventricular dimension to maximum elastance by fiber mechanics.

    PubMed

    Beyar, R; Sideman, S

    1986-09-01

    The dependence of the pressure-volume slope, which defines the maximum elastance (Emax) and the zero pressure-volume intercept (Vd) on the size and dimensions of the left ventricle (LV), is theoretically studied, and a normalizing parameter for Emax is suggested for normal and hypertrophied hearts. The study is based on our earlier model of the mechanics of the LV contraction, which assumes a nested-shell spheroidal shape, Streeter's fiber angle distribution, given stress-length and stress-strain rate functions of the sarcomeres, a radial propagation of the electrical activation front, and a windkessel arterial model. The study shows that Emax is linearly related to the maximum force that the optimal length sarcomeres can develop (sigma o), which is a characteristic measure of the contractility. Emax decreases and Vd increases with an increase in ventricular size, at a constant end-diastolic ratio (h/b)ed, where h is the wall thickness, and b is the semiminor axis of the prolate spheroidal LV. When the reference unstressed volume (V0) is held constant and the wall thickness increases, as in pure concentric hypertrophy, Emax decreases slightly and shifts to the left to a lower Vd value. In pure eccentric hypertrophy, wherein chamber size increases while the wall thickness remains constant, Emax decreases and Vd increases. A good index for myocardial function at constant configuration ratio (h/b)ed is obtained by multiplying Emax with the LV muscle volume (Vm). (h/b)ed is constant (= 0.45) for the normal heart but increases for concentric hypertrophy.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Vitamin D Status Is an Independent Risk Factor for Global Cognitive Impairment in Peritoneal Dialysis Patients

    PubMed Central

    Liu, Gui-Ling; Pi, Hai-Chen; Hao, Li; Li, Dan-Dan; Wu, Yong-Gui; Dong, Jie

    2015-01-01

    Objective Vitamin D (VD) deficiency is an independent risk factor for cognitive impairment (CI) in the general population, but VD status in peritoneal dialysis (PD) patients has not been investigated. In this study, we aimed to investigate the relationship between serum VD levels and global and specific cognitive functions in PD patients. Design and Setting Cross-sectional study, simultaneously conducted at two PD centers. Patients Clinically stable patients (n = 273) undergoing PD for at least 3 months were enrolled over a period of one year. Main outcome Measures Demographic and comorbidity data were recorded, and routine biochemical parameters and serum 25-hydroxyvitamin D (25(OH) D) levels of overnight fasted patients were determined. Global cognitive function was assessed by the Modified Mini-Mental State Examination (3MS) score; executive function, by the trail making tests (Trails A and B); and immediate memory, delayed memory, and language ability by the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) sub-tests. Results In the univariate analysis, serum 25(OH) D levels significantly correlated with 3MS scores (r = -0.139; P = 0.02), and Trail A (r = -0.188; P = 0.002) and B (r = -0.154; P = 0.01) completion times. In the multivariate analysis, 25(OH) D was found to be independently associated with global CI, but not with executive dysfunction. Serum 25(OH) D could not predict scores of immediate/delayed memory and language ability. Conclusions VD deficiency is highly prevalent in PD patients and is an independent risk factor for global CI in this patient cohort. PMID:26630385

  12. Vesicles from pH-regulated reversible gemini amino-acid surfactants as nanocapsules for delivery.

    PubMed

    Lv, Jing; Qiao, Weihong; Li, Zongshi

    2016-10-01

    Reversible transition from micelles to vesicles by regulating pH were realized by gemini amino-acid surfactants N,N'-dialkyl-N,N'-diacetate ethylenediamine. Measurement results of ζ-potential at different pH and DLS at varying solvents revealed that the protonation between H(+) and double NCH2COO(-) groups (generating NH(+)CH2COO(-)), expressed as pKa1 and pKa2, is the key driving force to control the aggregation behaviors of gemini surfactant molecule. Effect of pH on the bilayer structure was studied in detail by using steady-state fluorescence spectroscopy of hydrophobic pyrene and Coumarin 153 (C153) respectively and fluorescence resonance energy transfer (FRET) from C153 to Rhodamine 6G (R6G). Various pH-regulated and pH-reversible self-assemblies were obtained in one surfactant system. Vitamin D3 was encapsulated in vesicle bilayers to form nano-VD3-capsules as VD3 supplement agent for health care products. By using the electrostatic attraction between Ca(2+) and double -COO(-) groups, nano-VD3-capsules with Ca(2+) coated outermost layers were prepared as a formulation for VD3 and calcium co-supplement agent. DLS and TEM were performed to check stability and morphology of the nano-capsules. It is concluded that the pH-regulated gemini amino-acid surfactants can be used to construct colloidal systems for delivering hydrophobic drugs or nutritions without lipids at human physiological pH level.

  13. Changes in Maternal Plasma Adiponectin from Late Pregnancy to the Postpartum Period According to the Mode of Delivery: Results from a Prospective Cohort in Rio de Janeiro, Brazil

    PubMed Central

    Rebelo, Fernanda; Franco-Sena, Ana Beatriz; Struchiner, Claudio Jose; Kac, Gilberto

    2016-01-01

    Introduction Maternal plasma adiponectin is inversely related to insulin resistance, atherosclerosis and child health. However, little is known about its concentrations in the perinatal period, especially according to mode of delivery. Our aim is to evaluate the association between mode of delivery and changes in maternal plasma adiponectin from 3rd trimester of pregnancy to 30–45 days postpartum. Methods A cohort was recruited in Rio de Janeiro, Brazil, with four waves of follow-up: 5-13th, 22-26th, 30-36th gestational weeks and 30–45 days postpartum. Eligible subjects should be between 20–40 years of age, be free of chronic and infectious diseases and presenting with a singleton pregnancy. The mode of delivery was classified as vaginal (VD) or cesarean (CS). Plasma adiponectin concentration (μg/mL) was measured using commercial ELISA kits. Statistical analyses included the Wilcoxon rank-sum test and the multiple linear mixed effects model. Results A total of 159 participated in the study. Median adiponectin concentrations were higher for the VD group (n = 99; 8.25, IQR: 5.85–11.90) than for the CS group (n = 60; 7.34, IQR: 4.36–9.76; p = 0.040) in the postpartum samples but were not different between the two groups in the 3rd trimester. Women who underwent CS had a lower rate of increase in adiponectin concentration from the 3rd trimester to 30–45 days postpartum compared to those who underwent VD (β = -.15, 95% CI: -.28-.02, p = 0.030). Conclusion The CS procedure was associated with lower maternal circulating concentrations of adiponectin at 30–45 days postpartum, compared to the VD. PMID:27391647

  14. Higher latitude and lower solar radiation influence on anaphylaxis in Chilean children

    PubMed Central

    Hoyos-Bachiloglu, Rodrigo; Morales, Pamela S.; Cerda, Jaime; Talesnik, Eduardo; González, Gilberto; Camargo, Carlos A.; Borzutzky, Arturo

    2014-01-01

    Background Recent studies suggest an association between higher latitude, a proxy of vitamin D (VD) status, and allergic diseases. Chile provides an ideal setting to study this association due to its latitude span and high rates of VD deficiency in southern regions. The aim of this study is to explore the associations of latitude and solar radiation with anaphylaxis admission rates. Methods We reviewed anaphylaxis admissions in Chile’s hospital discharge database between 2001 and 2010 and investigated associations with latitude and solar radiation. Results 2316 anaphylaxis admissions were registered. Median age of patients was 41 years; 53% were female. National anaphylaxis admission rate was 1.41 per 100,000 persons per year. We observed a strong north-south increasing gradient of anaphylaxis admissions (β 0.04, P=0.01), with increasing rates south of latitude 34°S. A significant association was also observed between solar radiation and anaphylaxis admissions (β −0.11, P=0.009). Latitude was associated with food-induced (β 0.05, P=0.02), but not drug-induced (β −0.002, P=0.27), anaphylaxis. The association between latitude and food-induced anaphylaxis was significant in children (β 0.01, P=0.006), but not adults (β 0.003, P=0.16). Anaphylaxis admissions were not associated with regional sociodemographic factors like poverty, rurality, educational level, ethnicity, or physician density. Conclusions Anaphylaxis admission rates in Chile are highest at higher latitudes and lower solar radiation, used as proxies of VD status. The associations appear driven by food-induced anaphylaxis. Our data support a possible role of VD deficiency as an etiological factor in the high anaphylaxis admission rates found in southern Chile. PMID:24628618

  15. The effect of the exchange-correlation functional on H{sub 2} dissociation on Ru(0001)

    SciTech Connect

    Wijzenbroek, M.; Kroes, G. J.

    2014-02-28

    The specific reaction parameter (SRP) approach to density functional theory (DFT) has enabled a chemically accurate description of reactive scattering experiments for activated H{sub 2}–metal systems (H{sub 2} + Cu(111) and Cu(100)), but its application has not yet resulted in a similarly accurate description of non-activated or weakly activated H{sub 2}-metal systems. In this study, the effect of the choice of the exchange-correlation functional in DFT on the potential energy surface and dynamics of H{sub 2} dissociation on Ru(0001), a weakly activated system, is investigated. In total, full potential energy surfaces were calculated for over 20 different functionals. The functionals investigated include functionals incorporating an approximate description of the van der Waals dispersion in the correlation functional (vdW-DF and vdW-DF2 functionals), as well as the revTPSS meta-GGA. With two of the functionals investigated here, which include vdW-DF and vdW-DF2 correlation, it has been possible to accurately reproduce molecular beam experiments on sticking of H{sub 2} and D{sub 2}, as these functionals yield a reaction probability curve with an appropriate energy width. Diffraction probabilities computed with these two functionals are however too high compared to experimental diffraction probabilities, which are extrapolated from surface temperatures (T{sub s}) ⩾ 500 K to 0 K using a Debye–Waller model. Further research is needed to establish whether this constitutes a failure of the two candidate SRP functionals or a failure of the Debye–Waller model, the use of which can perhaps in future be avoided by performing calculations that include the effect of surface atom displacement or motion, and thereby of the experimental T{sub s}.

  16. The effect of the exchange-correlation functional on H2 dissociation on Ru(0001)

    NASA Astrophysics Data System (ADS)

    Wijzenbroek, M.; Kroes, G. J.

    2014-02-01

    The specific reaction parameter (SRP) approach to density functional theory (DFT) has enabled a chemically accurate description of reactive scattering experiments for activated H2-metal systems (H2 + Cu(111) and Cu(100)), but its application has not yet resulted in a similarly accurate description of non-activated or weakly activated H2-metal systems. In this study, the effect of the choice of the exchange-correlation functional in DFT on the potential energy surface and dynamics of H2 dissociation on Ru(0001), a weakly activated system, is investigated. In total, full potential energy surfaces were calculated for over 20 different functionals. The functionals investigated include functionals incorporating an approximate description of the van der Waals dispersion in the correlation functional (vdW-DF and vdW-DF2 functionals), as well as the revTPSS meta-GGA. With two of the functionals investigated here, which include vdW-DF and vdW-DF2 correlation, it has been possible to accurately reproduce molecular beam experiments on sticking of H2 and D2, as these functionals yield a reaction probability curve with an appropriate energy width. Diffraction probabilities computed with these two functionals are however too high compared to experimental diffraction probabilities, which are extrapolated from surface temperatures (Ts) ⩾ 500 K to 0 K using a Debye-Waller model. Further research is needed to establish whether this constitutes a failure of the two candidate SRP functionals or a failure of the Debye-Waller model, the use of which can perhaps in future be avoided by performing calculations that include the effect of surface atom displacement or motion, and thereby of the experimental Ts.

  17. Stability analysis of electrostatically actuated nano/micro-beams under the effect of van der Waals force, a semi-analytical approach

    NASA Astrophysics Data System (ADS)

    Askari, Amir R.; Tahani, Masoud

    2016-05-01

    The objective of the present paper is to determine pull-in parameters (pull-in voltage and its corresponding displacement) of nano/micro-beams with clamped-clamped, clamped-free, clamped-hinged and hinged-hinged boundary conditions, when they are subjected to the electrostatics and van der Waals (vdW) attractions. The governing non-linear boundary value equation of equilibrium is derived, non-dimensionalized and reduced to an algebraic equation, which describes the position of the maximum deflection of the beam, utilizing the Galerkin decomposition method. The equation which governs on the stability condition of the system is also obtained by differentiating the reduced equilibrium equation with respect to the maximum deflection of the beam. These two equations are solved simultaneously to determine pull-in parameters. Closed-form solutions are provided for cases under electrical loading and vdW attraction alone. The combined effect of both electrostatic and vdW loadings are also investigated using the homotopy perturbation method (HPM). It is found that the present semi-analytical findings are in excellent agreement with those obtained numerically. In addition, it is observed that the present semi-analytical approach can provide results which agree better with available three-dimensional finite element simulations as well as those obtained by nonlinear finite element method than other available analytical or semi-analytical findings in the literature. Non-dimensional electrostatic and vdW parameters, which are defined in the text, are plotted versus each other at pull-in condition. It is found that there exists a linear relationship between these two parameters at pull-in condition. Using this fact, pull-in voltage, detachment length and minimum allowable gap of electrostatically actuated nano/micro-beams are determined explicitly through some closed-form expressions.

  18. Bortezomib-based triplets are associated with a high probability of dialysis independence and rapid renal recovery in newly diagnosed myeloma patients with severe renal failure or those requiring dialysis.

    PubMed

    Dimopoulos, Meletios A; Roussou, Maria; Gavriatopoulou, Maria; Psimenou, Erasmia; Eleutherakis-Papaiakovou, Evangelos; Migkou, Magdalini; Matsouka, Charis; Mparmparousi, Despoina; Gika, Dimitra; Kafantari, Eftychia; Ziogas, Dimitrios; Fotiou, Despoina; Panagiotidis, Ioannis; Terpos, Evangelos; Kastritis, Efstathios

    2016-05-01

    Renal failure (RF) is a common and severe complication of symptomatic myeloma, associated with significant morbidity and mortality. Such patients are commonly excluded from clinical trials. Bortezomib/dexamethasone (VD)-based regimens are the backbone of the treatment of newly diagnosed MM patients who present with severe RF even those requiring dialysis. We analyzed the outcomes of 83 consecutive bortezomib-treated patients with severe RF (eGFR < 30 ml/min/1.73 m(2) ), of which 31 (37%) required dialysis. By IMWG renal response criteria, 54 (65%) patients achieved at least MRrenal, including CRrenal in 35% and PRrenal in 12%. Triplet combinations (i.e., VD plus a third agent) versus VD alone were associated with higher rates of renal responses (72 vs. 50%; P = 0.06). Fifteen of the 31 (48%) patients became dialysis independent within a median of 217 days (range 11-724). Triplets were associated with a higher probability of dialysis discontinuation (57 vs. 35%). Serum free light chain (sFLC) level ≥11,550 mg/L was associated with lower rates of major renal response, longer time to major renal response, lower probability, and longer time to dialysis discontinuation. Rapid myeloma response (≥PR within the first month) was also associated with higher rates of renal response. Patients who became dialysis-independent had longer survival than those remaining on dialysis. In conclusion, VD-based triplets are associated with a significant probability of renal response and dialysis discontinuation, improving the survival of patients who became dialysis independent. Rapid disease response is important for renal recovery and sFLCs are predictive of the probability and of the time required for renal response.

  19. Prediction of human pharmacokinetics using physiologically based modeling: a retrospective analysis of 26 clinically tested drugs.

    PubMed

    De Buck, Stefan S; Sinha, Vikash K; Fenu, Luca A; Nijsen, Marjoleen J; Mackie, Claire E; Gilissen, Ron A H J

    2007-10-01

    The aim of this study was to evaluate different physiologically based modeling strategies for the prediction of human pharmacokinetics. Plasma profiles after intravenous and oral dosing were simulated for 26 clinically tested drugs. Two mechanism-based predictions of human tissue-to-plasma partitioning (P(tp)) from physicochemical input (method Vd1) were evaluated for their ability to describe human volume of distribution at steady state (V(ss)). This method was compared with a strategy that combined predicted and experimentally determined in vivo rat P(tp) data (method Vd2). Best V(ss) predictions were obtained using method Vd2, providing that rat P(tp) input was corrected for interspecies differences in plasma protein binding (84% within 2-fold). V(ss) predictions from physicochemical input alone were poor (32% within 2-fold). Total body clearance (CL) was predicted as the sum of scaled rat renal clearance and hepatic clearance projected from in vitro metabolism data. Best CL predictions were obtained by disregarding both blood and microsomal or hepatocyte binding (method CL2, 74% within 2-fold), whereas strong bias was seen using both blood and microsomal or hepatocyte binding (method CL1, 53% within 2-fold). The physiologically based pharmacokinetics (PBPK) model, which combined methods Vd2 and CL2 yielded the most accurate predictions of in vivo terminal half-life (69% within 2-fold). The Gastroplus advanced compartmental absorption and transit model was used to construct an absorption-disposition model and provided accurate predictions of area under the plasma concentration-time profile, oral apparent volume of distribution, and maximum plasma concentration after oral dosing, with 74%, 70%, and 65% within 2-fold, respectively. This evaluation demonstrates that PBPK models can lead to reasonable predictions of human pharmacokinetics. PMID:17620347

  20. Efficient Parameter Estimation of Generalizable Coarse-Grained Protein Force Fields Using Contrastive Divergence: A Maximum Likelihood Approach

    PubMed Central

    2013-01-01

    Maximum Likelihood (ML) optimization schemes are widely used for parameter inference. They maximize the likelihood of some experimentally observed data, with respect to the model parameters iteratively, following the gradient of the logarithm of the likelihood. Here, we employ a ML inference scheme to infer a generalizable, physics-based coarse-grained protein model (which includes Go̅-like biasing terms to stabilize secondary structure elements in room-temperature simulations), using native conformations of a training set of proteins as the observed data. Contrastive divergence, a novel statistical machine learning technique, is used to efficiently approximate the direction of the gradient ascent, which enables the use of a large training set of proteins. Unlike previous work, the generalizability of the protein model allows the folding of peptides and a protein (protein G) which are not part of the training set. We compare the same force field with different van der Waals (vdW) potential forms: a hard cutoff model, and a Lennard-Jones (LJ) potential with vdW parameters inferred or adopted from the CHARMM or AMBER force fields. Simulations of peptides and protein G show that the LJ model with inferred parameters outperforms the hard cutoff potential, which is consistent with previous observations. Simulations using the LJ potential with inferred vdW parameters also outperforms the protein models with adopted vdW parameter values, demonstrating that model parameters generally cannot be used with force fields with different energy functions. The software is available at https://sites.google.com/site/crankite/. PMID:24683370