Frequencies and ethnic distribution of ABO and RhD blood groups in China: a population-based cross-sectional study.

Science.gov (United States)

Liu, Jue; Zhang, Shikun; Wang, Qiaomei; Shen, Haiping; Zhang, Yiping; Liu, Min

2017-12-03

ABO and RhD blood groups are key factors affecting blood transfusion safety. The distribution of ABO and RhD blood groups varies globally, but limited data exist for ethnic distributions of these blood groups in Asian populations. We aimed to evaluate the distribution of ABO and RhD blood groups among Chinese ethnic groups. A population-based cross-sectional study. Data on ABO groups and ethnicities were obtained from the National Free Preconception Health Examination Project (NFPHEP) with participants from 220 counties of 31 provinces in China PARTICIPANTS: There were 3 832 034 participants aged 21-49 years who took part in the NFPHEP from January 2010 to December 2012 and were included in this study. The proportion of ABO and RhD blood groups among different ethnic groups was calculated. ABO and RhD blood distribution was significantly different among nine ethnic groups (Pgroups, the Yi group had more A phenotypes (34.0%), and the Manchu (33.7%) and Mongolian (33.3%) ethnic groups had more B phenotypes. The Zhuang group had the greatest proportion of O phenotypes (41.8%), followed by the Miao group (37.7%). AB phenotypes were more frequent in the Uygur ethnic group (10.6%) but lower in the Zhuang group (5.5%). Meanwhile, RhD negativity (RhD-) was greater in the Uygur group (3.3%) than in the Mongolian (0.3%) and Manchu ethnic groups (0.4%). O RhD- blood groups were more frequent in the Uygur group (0.8%) than in the other ethnic groups (0.1%-0.4%, Pblood phenotypes vary across different ethnic groups in China. The diversity in the distribution of the ABO and RhD blood groups in different ethnic groups should be considered when developing rational and evidence-based strategies for blood collection and management. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Frequency of ABO, subgroup ABO and Rh(D) blood groups in major sudanese ethnic groups

International Nuclear Information System (INIS)

Hassan, F.M.

2010-01-01

Background: There are differences in the distribution of ABO, sub group A BO and Rh(D) blood groups in different populations of the world. Relatively little information is available about blood group distributions in Sudanese population. To see the frequency of ABO, subgroup ABO and Rh(D) blood groups in major Sudanese ethnic groups(Danagla Shaygia and Gaaleen). Blood testing for ABO, subgroup ABO and Rh(D) typing was done over six months, in 300 unrelated individuals, from both genders. Blood samples were collected from students of the college of medical laboratory science - Sudan University of Science and Technology using finger prick method and following routine slide method. Blood group 'O' was the most predominant ( 52.7%) in both Rh positive and negative subjects followed by blood group A, B and AB. Majority (98.0%)o f the subjects were Rh(D) positive and only 2% were Rh negative. The predominant subgroup of ABO was A2 (14.1% ). The frequency of ABO blood groups in both Rh positive and negative subjects among the major Sudanese ethnic group was similar to that reported from neighbouring regions. (author)

A DEL phenotype attributed to RHD Exon 9 sequence deletion: slipped-strand mispairing and blood group polymorphisms.

Science.gov (United States)

Lopez, Genghis H; Turner, Robyn M; McGowan, Eunike C; Schoeman, Elizna M; Scott, Stacy A; O'Brien, Helen; Millard, Glenda M; Roulis, Eileen V; Allen, Amanda J; Liew, Yew-Wah; Flower, Robert L; Hyland, Catherine A

2018-03-01

The RhD blood group antigen is extremely polymorphic and the DEL phenotype represents one such class of polymorphisms. The DEL phenotype prevalent in East Asian populations arises from a synonymous substitution defined as RHD*1227A. However, initially, based on genomic and cDNA studies, the genetic basis for a DEL phenotype in Taiwan was attributed to a deletion of RHD Exon 9 that was never verified at the genomic level by any other independent group. Here we investigate the genetic basis for a Caucasian donor with a DEL partial D phenotype and compare the genomic findings to those initial molecular studies. The 3'-region of the RHD gene was amplified by long-range polymerase chain reaction (PCR) for massively parallel sequencing. Primers were designed to encompass a deletion, flanking Exon 9, by standard PCR for Sanger sequencing. Targeted sequencing of exons and flanking introns was also performed. Genomic DNA exhibited a 1012-bp deletion spanning from Intron 8, across Exon 9 into Intron 9. The deletion breakpoints occurred between two 25-bp repeat motifs flanking Exon 9 such that one repeat sequence remained. Deletion mutations bordered by repeat sequences are a hallmark of slipped-strand mispairing (SSM) event. We propose this genetic mechanism generated the germline deletion in the Caucasian donor. Extensive studies show that the RHD*1227A is the most prevalent DEL allele in East Asian populations and may have confounded the initial molecular studies. Review of the literature revealed that the SSM model explains some of the extreme polymorphisms observed in the clinically significant RhD blood group antigen. © 2017 AABB.

Is current serologic RhD typing of blood donors sufficient for avoiding immunization of recipients?

DEFF Research Database (Denmark)

Krog, Grethe Risum; Clausen, Frederik Banch; Berkowicz, Adela

2011-01-01

Avoiding immunization with clinically important antibodies is a primary objective in transfusion medicine. Therefore, it is central to identify the extent of D antigens that escape routine RhD typing of blood donors and to improve methodology if necessary.......Avoiding immunization with clinically important antibodies is a primary objective in transfusion medicine. Therefore, it is central to identify the extent of D antigens that escape routine RhD typing of blood donors and to improve methodology if necessary....

[Hemolytic disease of the newborn has not vanished from Finland--routine protection of RhD negative mothers during pregnancy is justifiable].

Science.gov (United States)

Sainio, Susanna; Kuosmanen, Malla

2012-01-01

Prophylaxis of RhD negative mothers with anti-D immunoglobulin after childbirth is the most important procedure reducing the immunization of the mother and the risk of severe hemolytic disease of the newborn. In spite of this, anti-D antibodies having relevance to pregnancy are later detected in 1.8% of RhD negative mothers. Half of these cases could be prevented by routine anti-D prophylaxis given to the mothers during weeks 28 to 34 of pregnancy. Convincing evidence of the effectiveness of this measure has accumulated in the last few years, and application of the treatment is justified also in Finland.

Report of the first nationally implemented clinical routine screening for fetal RHD in D- pregnant women to ascertain the requirement for antenatal RhD prophylaxis

DEFF Research Database (Denmark)

Clausen, Frederik Banch; Christiansen, Mette; Steffensen, Rudi Nora

2012-01-01

- women who carry a D+ fetus. We present an evaluation of the first national clinical application of antenatal RHD screening. STUDY DESIGN AND METHODS: In each of the five Danish health care regions, blood samples were drawn from D- women in Gestational Week 25. DNA was extracted from the maternal plasma...

[Standardization of the quantitative flow cytometric test with anti-D antibodies for fetomaternal hemorrhage in RhD negative women].

Science.gov (United States)

Spychalska, Justyna; Uhrynowska, Małgorzata; Pyl, Hanna; Klimczak-Jajor, Edyta; Kopeć, Izabella; Peciakowska, Małgorzata; Gutowska, Renata; Gawlak, Maciej; Słomska, Sylwia; Dąbkowska, Syiwia; Szczecina, Roman; Dębska, Marzena; Brojer, Ewa

2015-07-01

In order to determine the appropriate dose of anti-D immunoglobulin to be administered as a preventive measure against hemolytic disease of the fetus/newborn in the subsequent pregnancy it is necessary to assess the number of fetal red blood cells that infiltrate/penetrate into the maternal circulation as a result of fetomaternal hemorrhage (FMH). One of the quantitative methods of FMH analysis is based on flow cytometry (FACS) which makes use of monoclonal antibodies to RhD antigen (anti-D test). The aim of the study was to further develop the method, evaluate its sensitivity and reproducibility and to compare it with the test based on the detection of fetal hemoglobin (HbF). The FACS study involved 20 RhD negative pregnant women and 80 RhD negative women after delivery. The following monoclonal antibodies were used: BRAD 3 FITC (anti-RhD antigen), CD45 PerCP (anti leukocyte antigen CD45), and anti-HbF PE. The fluorescence intensity of cells incubated with BRAD 3 FITC was demonstrated to depend on the RhD antigen expression, though the anti-D test also detects the weak D variant. The CD45 PerCP antibodies increased the sensitivity of anti-D test since they eliminated the leukocytes which non-specifically bind anti-D from the analysis. The presence of anti-D antibodies in maternal plasma does not affect the quantitative assessment of the fetal RhD positive fetal cells with BRAD 3 FITC. In case of FMH, the results of the anti-D test were similar to those with anti-HbF antibodies. The flow cytometric test with anti-D and anti-CD45 is useful in the assessment of the fetomaternal hemorrhage in RhD negative women. The sensitivity of the test is estimated at 0.05%.

Acquired RhD mosaicism identifies fibrotic transformation of thrombopoietin receptor-mutated essential thrombocythemia.

Science.gov (United States)

Montemayor-Garcia, Celina; Coward, Rebecca; Albitar, Maher; Udani, Rupa; Jain, Prachi; Koklanaris, Eleftheria; Battiwalla, Minoo; Keel, Siobán; Klein, Harvey G; Barrett, A John; Ito, Sawa

2017-09-01

Acquired copy-neutral loss of heterozygosity has been described in myeloid malignant progression with an otherwise normal karyotype. A 65-year-old woman with MPL-mutated essential thrombocythemia and progression to myelofibrosis was noted upon routine pretransplant testing to have mixed field reactivity with anti-D and an historic discrepancy in RhD type. The patient had never received transfusions or transplantation. Gel immunoagglutination revealed group A red blood cells and a mixed-field reaction for the D phenotype, with a predominant D-negative population and a small subset of circulating red blood cells carrying the D antigen. Subsequent genomic microarray single nucleotide polymorphism profiling revealed copy-neutral loss of heterozygosity of chromosome 1 p36.33-p34.2, a known molecular mechanism underlying fibrotic progression of MPL-mutated essential thrombocythemia. The chromosomal region affected by this copy-neutral loss of heterozygosity encompassed the RHD, RHCE, and MPL genes. We propose a model of chronological molecular events that is supported by RHD zygosity assays in peripheral lymphoid and myeloid-derived cells. Copy-neutral loss of heterozygosity events that lead to clonal selection and myeloid malignant progression may also affect the expression of adjacent unrelated genes, including those encoding for blood group antigens. Detection of mixed-field reactions and investigation of discrepant blood typing results are important for proper transfusion support of these patients and can provide useful surrogate markers of myeloproliferative disease progression. © 2017 AABB.

Rh(D) fraction incompatibility causing hemolytic disease of the newborn. Report of two cases in a Chinese family.

Science.gov (United States)

Lee, S K; Tham, K T; Cheung, K P; Jenkins, W J

1982-07-01

Two cases of hemolytic disease of new born in a Chinese family are reported. The hemolysis was due to the production in the mother of antibodies against fractions A, C, and D of Rh(D) antigen. The fractions were absent in the mother's red blood cells which are Rh(DB) but present in her babies. Rh(DB) may be detected by the use of two types of anti-D sera, one with and the other without anti-DB activity. For transfusion purpose, all DB patients so tested, would be regarded as Rh(D) negative.

Risk factors for RhD immunisation despite antenatal and postnatal anti-D prophylaxis

NARCIS (Netherlands)

Koelewijn, J. M.; de Haas, M.; Vrijkotte, T. G. M.; van der Schoot, C. E.; Bonsel, G. J.

2009-01-01

Objective To identify risk factors for Rhesus D (RhD) immunisation in pregnancy, despite adequate antenatal and postnatal anti-D prophylaxis in the previous pregnancy. To generate evidence for improved primary prevention by extra administration of anti-D Ig in the presence of a risk factor. Design

A case of high-titer anti-D hemolytic disease of the newborn in which late onset and mild course is associated with the D variant, RHD-CE(9)-D

DEFF Research Database (Denmark)

Jakobsen, Marianne A; Nielsen, Christian; Sprogøe, Ulrik

2014-01-01

BACKGROUND: The RhD antigen is very immunogenic and is a significant cause of hemolytic disease of the newborn (HDN). The RHD-CE(8-9)-D hybrid allele is commonly associated with a D- phenotype. Here, we report a case of high-titer maternal anti-D and late onset of HDN in a newborn carrying a RHD......-CE(9)-D variant supposedly encoding the same partial D antigen as the RHD-CE(8-9)-D allele, but with significant expression of D antigen. STUDY DESIGN AND METHODS: To elucidate the blood group antigen background of the case, we carried out serologic, flow cytometric, and genetics studies of the newborn...

Pre-Analytical Conditions in Non-Invasive Prenatal Testing of Cell-Free Fetal RHD

DEFF Research Database (Denmark)

Clausen, Frederik Banch; Jakobsen, Tanja Roien; Rieneck, Klaus

2013-01-01

D positive fetus. Prophylaxis reduces the risk of immunization that may lead to hemolytic disease of the fetus and the newborn. The reliability of predicting the fetal RhD type depends on pre-analytical factors and assay sensitivity. We evaluated the testing setup in the Capital Region of Denmark, based...

A case of high-titer anti-D hemolytic disease of the newborn in which late onset and mild course is associated with the D variant, RHD-CE(9)-D.

Science.gov (United States)

Jakobsen, Marianne A; Nielsen, Christian; Sprogøe, Ulrik

2014-10-01

The RhD antigen is very immunogenic and is a significant cause of hemolytic disease of the newborn (HDN). The RHD-CE(8-9)-D hybrid allele is commonly associated with a D- phenotype. Here, we report a case of high-titer maternal anti-D and late onset of HDN in a newborn carrying a RHD-CE(9)-D variant supposedly encoding the same partial D antigen as the RHD-CE(8-9)-D allele, but with significant expression of D antigen. To elucidate the blood group antigen background of the case, we carried out serologic, flow cytometric, and genetics studies of the newborn and his father. Individuals carrying the RHD-CE(9)-D allele do express D antigen, but do so at significantly lower levels than those carrying the more common D+ phenotypes (e.g., DCe/dce). It may mitigate and delay otherwise severe HDN in pregnancies complicated by high-titer anti-D. © 2014 AABB.

Distribution of ABO and Rh-D blood groups in the Benin area of Niger-Delta: Implication for regional blood transfusion

Directory of Open Access Journals (Sweden)

Enosolease Mathew

2008-01-01

Full Text Available ABO and Rhesus (Rh blood group antigens are hereditary characters and are useful in population genetic studies, in resolving medico-legal issues and more importantly in compatibility test in blood transfusion practice. Data on frequency distribution of ABO and Rh-D in Niger-Delta region of Nigeria are not available; hence we made an attempt to retrospectively analyze the records on the blood donors, transfusion recipients and patients attending antenatal care or some other medical interventions. Over a twenty-year period between 1986 and 2005, a total of 160,431 blood samples were grouped for ABO and Rh-D at the blood bank of the University of Benin Teaching Hospital, Benin City, Nigeria. Blood group distribution among these samples showed phenotypes A, B, AB and O as 23.72%, 20.09%, 2.97% and 53.22%, respectively. The Rh-D negative phenotype was found among 6.01% of the samples tested.

Prevalence and gene frequencies of A1A2BO and Rh(D) blood ...

African Journals Online (AJOL)

Ruqaiya Hussain

2012-08-03

Aug 3, 2012 ... Human Genetics and Toxicology Lab, Section of Genetics, Department of Zoology ... alence and gene frequencies of A1A2BO and Rh(D) blood groups among the Muslim populations of ..... The principal bio-clinical significance of the erythrocytic ... (CST), UP, which funded the major project, titled '' Genomic.

Risk Factors for RhD Immunisation Despite Antenatal and Postnatal Anti-D Prophylaxis COMMENT

NARCIS (Netherlands)

Koelewijn, J. M.; de Haas, M.; Vrijkotte, T. G. M.; van der Schoot, C. E.; Bonsel, G. J.

2010-01-01

Despite routine antenatal and postnatal administration of anti-D immunoglobulin (Ig) during pregnancy and delivery in a previous pregnancy, 0.1% to 0.3% of women are found to have Rhesus D (RhD) antibodies in their next pregnancy. The primary aim of this case-control study was to identify causative

Women's attitude towards prenatal screening for red blood cell antibodies, other than RhD

NARCIS (Netherlands)

J. Koelewijn; T.G.M. Vrijkotte (Tanja); M. de Haas; C.E. van der Schoot (Ellen); G.J. Bonsel (Gouke)

2008-01-01

textabstractBackground: Since July 1998 all Dutch women (± 200,000/y) are screened for red cell antibodies, other than anti-RhesusD (RhD) in the first trimester of pregnancy, to facilitate timely treatment of pregnancies at risk for hemolytic disease of the fetus and newborn (HDFN). Evidence for

DAR, a new RhD variant involving exons 4, 5, and 7, often in linkage with ceAR, a new Rhce variant frequently found in African blacks

NARCIS (Netherlands)

M.B. Hemker (Mirte); P.C. Ligthart; L. Berger (Loïc); D.J. van Rhenen (Dirk Jan); C.E. van der Schoot (Ellen); P.A. Wijk

1999-01-01

textabstractThe highly polymorphic Rh system is encoded by 2 homologous genes RHD and RHCE. Gene rearrangements, deletions, or point mutations may cause partial D and CE antigens. In this study, a new RHD variant, DAR, and a new RHCE variant, ceAR, are described in 4

Serological Survey for RHD Antibodies in Rabbits from Two Types of Rabbit Breeding Farms.

Science.gov (United States)

Fitzner, A; Niedbalski, W

2016-09-01

Seroprevalence studies of RHDV antibodies in domestic rabbits were conducted between 2008-2014. A total of 12,169 sera from the provinces of central, southern and south-east Poland, including 7,570 samples collected from mixed-breed rabbits reared in smallholder farms and nearly 4,600 sera taken mainly from unvaccinated rabbits kept in industrial farms, were examined using ELISA tests. Additionally, cross-reactivity of selected tested and control archival sera using both classic RHDV and RHDVa antigens was determined by HI assay. The overall seroprevalence was 13.3%. In rabbits with unkown history of immunisation or RHD infection which came from small farms, RHDV antibodies were detected in 6.1% ranging between 1.0% to 17.2% of animals. In rabbits of the same group, but with a declared vaccination status, or confirmed exposure to an infectious virus, or coming from exposed females, the seroprevalence ranged from 83% to 100%. Among unvaccinated meat rabbits aged 71 to 90 days from industrial farms, low (1.85%, 4.17%, 11%), medium (34%, 54%) or high rates (98.7%) of seropositivity were detected. The seroconversion recorded in adult vaccinated females from industrial farms was 70% and 95%. Generally, the antibody levels examined by ELISAs and HI were comparable. However, a number of sera from the rabbits from small farms, as well as archival sera, showed clear differences. Several-fold differences in antibody titers, evidenced mainly in the postoutbreak sera, indictaed the contact of animals with RHDVa antigen. The overall results of the survey revealed a great proportion of seronegative rabbits potentially highly susceptible to RHD infection. In combination with the emergence of a novel pathogenic RHD virus type (RHDV2), it poses a severe risk of a next wave of fatal disease cases spreading in the native population of domestic rabbits, especially in farms with a traditional system of husbandry.

DAR, a new RhD variant involving exons 4, 5, and 7, often in linkage with ceAR, a new Rhce variant frequently found in African blacks

NARCIS (Netherlands)

Hemker, M. B.; Ligthart, P. C.; Berger, L.; van Rhenen, D. J.; van der Schoot, C. E.; Wijk, P. A.

1999-01-01

The highly polymorphic Rh system is encoded by 2 homologous genes RHD and RHCE. Gene rearrangements, deletions, or point mutations may cause partial D and CE antigens. In this study, a new RHD variant, DAR, and a new RHCE variant, ceAR, are described in 4 Dutch African Blacks. Serologically, DAR

Taiwan experience suggests that RhD typing for blood transfusion is unnecessary in southeast Asian populations.

Science.gov (United States)

Lin, Marie

2006-01-01

The high frequency of RhD (D) antigen among Taiwanese persons (99.67%) often imposes unnecessary risks of under-transfusion on D- patients awaiting D- blood. Also because of the rare occurrence of anti-D among Taiwanese persons, routine pretransfusion D typing has been discontinued in the Mackay Memorial Hospital since 1988. This report is the retrospective evaluation of the outcome of abolishing RhD typing for Taiwanese. More than 10 years of alloantibody data at Mackay Memorial Hospital Blood Bank were reviewed. The cases with anti-D were further used to analyze the potency of D antigen and to observe whether there were differences in the incidence of anti-D before and after discontinuation of routine D typing among Taiwanese individuals. The incidence of anti-D before and after discontinuation of routine pretransfusion D typing has remained unchanged. The immunogenicity of D and "Mi(a)" in Taiwanese persons is found to be similar. In terms of opportunity for immunization, however, the "Mi(a)" antigen (phenotype frequency 7.3% in Taiwanese persons) has become the most important blood group antigen in Taiwan. The results strongly support the exclusion of D typing from routine compatibility testing for individuals of Taiwanese origin. Because the low incidence of D- and relatively high incidence of "Mi(a)"+ phenotypes are common findings throughout southeast Asia, and because a population genetic study revealed that the Taiwanese people are genetically related to southern Asian populations, it is suggested that RhD typing for blood transfusion is unnecessary among southeast Asian populations.

Anti-D in a mother, hemizygous for the variant RHD*DNB gene, associated with hemolytic disease of the fetus and newborn.

Science.gov (United States)

Quantock, Kelli M; Lopez, Genghis H; Hyland, Catherine A; Liew, Yew-Wah; Flower, Robert L; Niemann, Frans J; Joyce, Arthur

2017-08-01

Individuals with the partial D phenotype when exposed to D+ red blood cells (RBCs) carrying the epitopes they lack may develop anti-D specific for the missing epitopes. DNB is the most common partial D in Caucasians and the clinical significance for anti-D in these individuals is unknown. This article describes the serologic genotyping results and clinical manifestations in two group D+ babies of a mother presenting as group O, D+ with alloanti-D. The mother was hemizygous for RHD*DNB gene and sequencing confirmed a single-nucleotide change at c.1063G>A. One baby (group A, D+) displayed bilirubinemia at birth with a normal hemoglobin level. Anti-A and anti-D were eluted from the RBCs. For the next ongoing pregnancy, the anti-D titer increased from 32 to 256. On delivery the baby typed group O and anti-D was eluted from the RBCs. This baby at birth exhibited anemia, reticulocytosis, and hyperbilirubinemia requiring intensive phototherapy treatment from Day 0 to Day 9 after birth and was discharged on Day 13. Intravenous immunoglobulin was also administered. Both babies were heterozygous for RHD and RHD*DNB. The anti-D produced by this woman with partial D DNB resulted in a case of hemolytic disease of the fetus and newborn (HDFN) requiring intensive treatment in the perinatal period. Anti-D formed by women with the partial D DNB phenotype has the potential to cause HDFN where the fetus is D+. Women carrying RHD*DNB should be offered appropriate prophylactic anti-D and be transfused with D- RBCs if not already alloimmunized. © 2017 AABB.

Ethical precepts for medical volunteerism: including local voices and values to guide RHD surgery in Rwanda.

Science.gov (United States)

Coors, Marilyn E; Matthew, Thomas L; Matthew, Dayna B

2015-10-01

At the invitation of the Rwandan Government, Team Heart, a team of American healthcare professionals, performs volunteer rheumatic heart disease (RHD) surgery in Rwanda every year, and confronts ethical concerns that call for cultural sensitivity. This article describes how five standard bioethical precepts are applied in practice in medical volunteerism related to RHD surgery in Rwanda. The content for the applied precepts stems from semiscripted, transcribed conversations with the authors, two Rwandan cardiologists, a Rwandan nurse and a Rwandan premedical student. The conversations revealed that the criteria for RHD surgical selection in Rwanda are analogous to the patient-selection process involving material scarcity in the USA. Rwandan notions of benefit and harm focus more attention on structural issues, such as shared benefit, national reputation and expansion of expertise, than traditional Western notions. Harm caused by inadequate patient follow-up remains a critical concern. Gender disparities regarding biological and social implications of surgical valve choices impact considerations of justice. Individual agency remains important, but not central to Rwandan concepts of justice, transparency and respect, particularly regarding women. The Rwandan understanding of standard bioethical precepts is substantively similar to the traditionally recognised interpretation with important contextual differences. The communal importance of improving the health of a small number of individuals may be underestimated in previous literature. Moreover, openness and the incorporation of Rwandan stakeholders in difficult ethical choices and long-term contributions to indigenous medical capacity appear to be valued by Rwandans. These descriptions of applied precepts are applicable to different medical missions in other emerging nations following a similar process of inclusion. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted

S-nitrosoglutathione promotes cell wall remodelling, alters the transcriptional profile and induces root hair formation in the hairless root hair defective 6 (rhd6) mutant of Arabidopsis thaliana.

Science.gov (United States)

Moro, Camila Fernandes; Gaspar, Marilia; da Silva, Felipe Rodrigues; Pattathil, Sivakumar; Hahn, Michael G; Salgado, Ione; Braga, Marcia Regina

2017-03-01

Nitric oxide (NO) exerts pleiotropic effects on plant development; however, its involvement in cell wall modification during root hair formation (RHF) has not yet been addressed. Here, mutants of Arabidopsis thaliana with altered root hair phenotypes were used to assess the involvement of S-nitrosoglutathione (GSNO), the primary NO source, in cell wall dynamics and gene expression in roots induced to form hairs. GSNO and auxin restored the root hair phenotype of the hairless root hair defective 6 (rhd6) mutant. A positive correlation was observed between increased NO production and RHF induced by auxin in rhd6 and transparent testa glabra (ttg) mutants. Deposition of an epitope within rhamnogalacturonan-I recognized by the CCRC-M2 antibody was delayed in root hair cells (trichoblasts) compared with nonhair cells (atrichoblasts). GSNO, but not auxin, restored the wild-type root glycome and transcriptome profiles in rhd6, modulating the expression of a large number of genes related to cell wall composition and metabolism, as well as those encoding ribosomal proteins, DNA and histone-modifying enzymes and proteins involved in post-translational modification. Our results demonstrate that NO plays a key role in cell wall remodelling in trichoblasts and suggest that it also participates in chromatin modification in root cells of A. thaliana. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

A new fetal RHD genotyping test: costs and benefits of mass testing to target antenatal anti-D prophylaxis in England and Wales.

Science.gov (United States)

Szczepura, Ala; Osipenko, Leeza; Freeman, Karoline

2011-01-18

Postnatal and antenatal anti-D prophylaxis have dramatically reduced maternal sensitisations and cases of rhesus disease in babies born to women with RhD negative blood group. Recent scientific advances mean that non-invasive prenatal diagnosis (NIPD), based on the presence of cell-free fetal DNA in maternal plasma, could be used to target prophylaxis on "at risk" pregnancies where the fetus is RhD positive. This paper provides the first assessment of cost-effectiveness of NIPD-targeted prophylaxis compared to current policies. We conducted an economic analysis of NIPD implementation in England and Wales. Two scenarios were considered. Scenario 1 assumed that NIPD will be only used to target antenatal prophylaxis with serology tests continuing to direct post-delivery prophylaxis. In Scenario 2, NIPD would also displace postnatal serology testing if an RhD negative fetus was identified. Costs were estimated from the provider's perspective for both scenarios together with a threshold royalty fee per test. Incremental costs were compared with clinical implications. The basic cost of an NIPD in-house test is £16.25 per sample (excluding royalty fee). The two-dose antenatal prophylaxis policy recommended by NICE is estimated to cost the NHS £3.37 million each year. The estimated threshold royalty fee is £2.18 and £8.83 for Scenarios 1 and 2 respectively. At a £2.00 royalty fee, mass NIPD testing would produce no saving for Scenario 1 and £507,154 per annum for Scenario 2. Incremental cost-effectiveness analysis indicates that, at a test sensitivity of 99.7% and this royalty fee, NIPD testing in Scenario 2 will generate one additional sensitisation for every £9,190 saved. If a single-dose prophylaxis policy were implemented nationally, as recently recommended by NICE, Scenario 2 savings would fall. Currently, NIPD testing to target anti-D prophylaxis is unlikely to be sufficiently cost-effective to warrant its large scale introduction in England and Wales. Only

Screening and identification of RhD antigen mimic epitopes from a phage display random peptide library for the serodiagnosis of haemolytic disease of the foetus and newborn.

Science.gov (United States)

Wang, Jiao; Song, Jingjing; Zhou, Shuimei; Fu, Yourong; Bailey, Jeffrey A; Shen, Changxin

2018-01-16

Identification of RhD antigen epitopes is a key component in understanding the pathogenesis of haemolytic disease of the foetus and newborn. Research has indicated that phage display libraries are useful tools for identifying novel mimic epitopes (mimotopes) which may help to determine antigen specificity. We selected the mimotopes of blood group RhD antigen by affinity panning a phage display library using monoclonal anti-D. After three rounds of biopanning, positive phage clones were identified by enzyme-linked immunosorbent assay (ELISA) and then sent for sequencing and peptides synthesis. Next, competitive ELISA and erythrocyte haemagglutination inhibition tests were carried out to confirm the inhibitory activity of the synthetic peptide. To evaluate the diagnostic performance of the synthetic peptide, a diagnostic ELISA was examined. Fourteen of 35 phage clones that were chosen randomly from the titering plate were considered to be positive. Following DNA sequencing and translation, 11 phage clones were found to represent the same peptide - RMKMLMMLMRRK (P4) - whereas each of the other three clones represented a unique peptide. Through the competitive ELISA and erythrocyte haemagglutination inhibition tests, the peptide (P4) was verified to have the ability to mimic the RhD antigen. The diagnostic ELISA for P4 proved to be sensitive (82.61%) and specific (88.57%). This study reveals that the P4 peptide can mimic RhD antigen and paves the way for the development of promising targeted diagnostic and therapeutic platforms for haemolytic disease of the foetus and newborn.

A new fetal RHD genotyping test: Costs and benefits of mass testing to target antenatal anti-D prophylaxis in England and Wales

Directory of Open Access Journals (Sweden)

Osipenko Leeza

2011-01-01

Full Text Available Abstract Background Postnatal and antenatal anti-D prophylaxis have dramatically reduced maternal sensitisations and cases of rhesus disease in babies born to women with RhD negative blood group. Recent scientific advances mean that non-invasive prenatal diagnosis (NIPD, based on the presence of cell-free fetal DNA in maternal plasma, could be used to target prophylaxis on "at risk" pregnancies where the fetus is RhD positive. This paper provides the first assessment of cost-effectiveness of NIPD-targeted prophylaxis compared to current policies. Methods We conducted an economic analysis of NIPD implementation in England and Wales. Two scenarios were considered. Scenario 1 assumed that NIPD will be only used to target antenatal prophylaxis with serology tests continuing to direct post-delivery prophylaxis. In Scenario 2, NIPD would also displace postnatal serology testing if an RhD negative fetus was identified. Costs were estimated from the provider's perspective for both scenarios together with a threshold royalty fee per test. Incremental costs were compared with clinical implications. Results The basic cost of an NIPD in-house test is £16.25 per sample (excluding royalty fee. The two-dose antenatal prophylaxis policy recommended by NICE is estimated to cost the NHS £3.37 million each year. The estimated threshold royalty fee is £2.18 and £8.83 for Scenarios 1 and 2 respectively. At a £2.00 royalty fee, mass NIPD testing would produce no saving for Scenario 1 and £507,154 per annum for Scenario 2. Incremental cost-effectiveness analysis indicates that, at a test sensitivity of 99.7% and this royalty fee, NIPD testing in Scenario 2 will generate one additional sensitisation for every £9,190 saved. If a single-dose prophylaxis policy were implemented nationally, as recently recommended by NICE, Scenario 2 savings would fall. Conclusions Currently, NIPD testing to target anti-D prophylaxis is unlikely to be sufficiently cost-effective to

No Acoustic Evidence from RHD for a Right Hemisphere Role in Prosody Production: A Meta-Analysis

DEFF Research Database (Denmark)

Weed, Ethan; Fusaroli, Riccardo

No acoustic evidence from RHD for a right hemisphere role in prosody production: A meta-analysis. Ethan Weed and Riccardo Fusaroli (Aarhus University, Denmark) Poster : The right hemisphere (RH) is often thought to have a special role in prosody comprehension and production in general...... by regression analysis of funnel plots for F0 (z = 1.5937, p = 0.1110). Intensity did show evidence of publication bias (z = -4.1582, p role for the RH in prosody...

Frequencies and ethnic distribution of ABO and Rh(D) blood groups in Mauritania: results of first nationwide study.

Science.gov (United States)

Hamed, C T; Bollahi, M A; Abdelhamid, I; Med Mahmoud, M A; Ba, B; Ghaber, S; Habti, N; Houmeida, A

2012-04-01

There is no data available on the ABO/Rh(D) frequencies in the Mauritanian population. We retrospectively analysed records of a 5-year database that contained ABO/Rh phenotype and ethnic origin of 10 116 volunteers giving blood at the national blood transfusion centre to derive the frequencies of ABO/Rh(D) groups in the Mauritanian population. The two race categories in the country and their sub-ethnic groups: the Moors (whites and black) and the black Africans (Pulhars, Soninkes and Wolof) were included in this study. Globally, group O had the highest frequency (49.10%) followed by A (28.28%), B (18.56%) and AB (4.05%). This order more common in North African populations was found in four of the five ethnic groups composing our population. Allele frequencies were, respectively, 70.20%, 17.74% and 12.04% giving the same order of O > A > B. We observed no significant variation in these frequencies between the different ethnic groups. Rhesus study showed that with a percentage of 94.23% Rh(D) positive is by far the most prevalent, while Rh(D) negative is present only in 5.77% of the total population. This frequency distribution supports the mixed-race composition of the Mauritanian population. © 2011 Blackwell Publishing Ltd.

ABO and RhD blood groups and gestational hypertensive disorders: a population-based cohort study.

Science.gov (United States)

Lee, B K; Zhang, Z; Wikman, A; Lindqvist, P G; Reilly, M

2012-09-01

To examine the association between ABO and RhD blood groups and gestational hypertensive disorders in a large population-based cohort. Cohort study. Risks of gestational hypertensive disorders, pre-eclampsia, and severe pre-eclampsia, estimated by odds ratios for maternal ABO blood group and RhD status. National health registers of Sweden. All singleton deliveries in Sweden born to first-time mothers during the period 1987-2002 [total n = 641 926; any gestational hypertensive disorders, n = 39 011 (6.1%); pre-eclampsia cases, n = 29 337 (4.6%); severe pre-eclampsia cases, n = 8477 (1.3%)]. Using blood group O as a reference, odds ratios of gestational hypertensive disorders, pre-eclampsia, and severe pre-eclampsia were obtained from logistic regression models adjusted for potential confounding factors. Gestational hypertensive disorders, pre-eclampsia, and severe pre-eclampsia. Compared with blood group O, all non-O blood groups had modest but statistically significantly higher odds of pre-eclampsia. Blood group AB had the highest risk for pre-eclampsia (OR = 1.10, 95% CI 1.04-1.16) and severe pre-eclampsia (OR = 1.18, 95% CI 1.07-1.30). RhD-positive mothers had a small increased risk for pre-eclampsia (OR = 1.07, 95% CI 1.03-1.10). In the largest study on this topic to date, women with AB blood group have the highest risks of gestational hypertensive disorders, pre-eclampsia, and severe pre-eclampsia, whereas women with O blood group have the lowest risks of developing these disorders. Although the magnitude of increased risk is small, this finding may help improve our understanding of the etiology of pre-eclampsia. © 2012 The Authors BJOG An International Journal of Obstetrics and Gynaecology © 2012 RCOG.

Modeling Exoplanetary Atmospheres using BART, TEA, and Drift-RHD; Theoretical studies and Observational Implications

Science.gov (United States)

Dobbs-Dixon, Ian

The explosion in the number of exoplanets detected to date has revealed a surprising diversity. When attempting to model this diversity, it is crucial to account for the uncertainties resulting from our limited knowledge of chemical, dynamical, and cloud formation processes in their atmospheres. Combining a retrieval technique with theorydriven models is a particularly promising way to address these processes and constrain a physically plausible atmospheric structure. In particular, a detailed micro-physical treatment of clouds and the longitudinal and latitudinal assessments of temperature and chemical profiles, have yet to be addressed in the field. Our team members are experts in radiative-hydrodynamic modeling (Dr. Ian DobbsDixon), cloud kinetics (Dr. Christiana Helling), retrievals and thermo-equilibrium chemistry (Dr. Jasmina Blecic), and observational diagnostics and predictions (Dr. Thomas Greene). The key goals of this proposal are to extend our understanding of the 3D atmospheric structure of gas-giant exoplanets by coupling state-of-the-art selfconsistent models together with a retrieval framework to 1) address cloud kinetics in retrievals, 2) assess 3D temperature and chemical structures in retrievals, 3) model a suite of well-observed planets within the framework of our models, and 4) make observational predictions for current and future NASA missions. To address these goals we have developed a number of tools: Drift-RHD, TEA, BART, and OBS. Drift-RHD solves both the 3D radiative-hydrodynamic equations and a time dependent kinetic cloud model. TEA, Thermochemical Equilibrium Abundances, calculates abundances of chemical species present in the atmosphere. BART, a Bayesian Atmospheric Radiative Transfer code, is a statistical retrieval framework to explore the parameter space of atmospheric chemical abundances and thermal profiles. OBS is a suite of tools developed to simulate observations. Though these tools exist and have been utilized independently in

Performance of Droplet Digital PCR in Non-Invasive Fetal RHD Genotyping - Comparison with a Routine Real-Time PCR Based Approach.

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Iveta Svobodová

Full Text Available Detection and characterization of circulating cell-free fetal DNA (cffDNA from maternal circulation requires an extremely sensitive and precise method due to very low cffDNA concentration. In our study, droplet digital PCR (ddPCR was implemented for fetal RHD genotyping from maternal plasma to compare this new quantification alternative with real-time PCR (qPCR as a golden standard for quantitative analysis of cffDNA. In the first stage of study, a DNA quantification standard was used. Clinical samples, including 10 non-pregnant and 35 pregnant women, were analyzed as a next step. Both methods' performance parameters-standard curve linearity, detection limit and measurement precision-were evaluated. ddPCR in comparison with qPCR has demonstrated sufficient sensitivity for analysing of cffDNA and determination of fetal RhD status from maternal circulation, results of both methods strongly correlated. Despite the more demanding workflow, ddPCR was found to be slightly more precise technology, as evaluated using quantitative standard. Regarding the clinical samples, the precision of both methods equalized with decreasing concentrations of tested DNA samples. In case of cffDNA with very low concentrations, variance parameters of both techniques were comparable. Detected levels of fetal cfDNA in maternal plasma were slightly higher than expected and correlated significantly with gestational age as measured by both methods (ddPCR r = 0.459; qPCR r = 0.438.

Inferencing Processes after Right Hemisphere Brain Damage: Effects of Contextual Bias

Science.gov (United States)

Blake, Margaret Lehman

2009-01-01

Purpose: Comprehension deficits associated with right hemisphere brain damage (RHD) have been attributed to an inability to use context, but there is little direct evidence to support the claim. This study evaluated the effect of varying contextual bias on predictive inferencing by adults with RHD. Method: Fourteen adults with no brain damage…

Excitation function and yield for the 103Rh(d,2n)103Pd nuclear reaction: Optimization of the production of palladium-103

International Nuclear Information System (INIS)

Manenti, Simone; Alí Santoro, María del Carmen; Cotogno, Giulio; Duchemin, Charlotte; Haddad, Ferid; Holzwarth, Uwe; Groppi, Flavia

2017-01-01

Deuteron-induced nuclear reactions for the generation of 103 Pd were investigated using the stacked-foil activation technique on rhodium targets at deuteron energies up to E d = 33 MeV. The excitation functions of the reactions 103 Rh(d,xn) 101,103 Pd, 103 Rh(d,x) 100g,cum,101m,g,102m,g Rh and 103 Rh(d,2p) 103 Ru have been measured, and the Thick-Target Yield for 103 Pd has been calculated.

Immunologic basis and immunoprophylaxis of RhD induced hemolytic disease of the newborn (HDN).

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Payam Khaja Pasha, Roya; Shokri, Fazel

2008-12-01

RhD antigen is the most immunogenic and clinically significant antigen of red blood cells after ABO system. It has historically been associated with hemolytic disease of the newborn (HDN) which is now routinely prevented by the administration of polyclonal anti-D immunoglobulin. This management of HDN has proven to be one of the most successful cases of prophylactic treatment based on antibody mediated immune suppression (AMIS). Despite the increasing efficiency of treatment, the mechanism of action of anti-D is not completely defined. There is a widespread interest in obtaining a reliable therapeutic monoclonal anti-D, due to difficulty of maintaining a pool of high titer volunteer donors for plasma collection and also increasing demand for antenatal prophylaxis and safety issues with plasma derived products. Candidate monoclonal anti-D preparations should demonstrate appropriate functionality in both in vitro and in vivo assays comparable to polyclonal anti-D immunoglobulin. These criteria are reviewed in addition to the factors regulating development of D specific immune response in D negative individuals and its suppression in HDN prophylaxis.

A study on interaction of DNA molecules and carbon nanotubes for an effective ejection of the molecules

International Nuclear Information System (INIS)

Wu, N.; Wang, Q.

2012-01-01

The ejection of DNA molecules from carbon nanotubes is reported from interaction energy perspectives by molecular dynamics simulations. The critical ejection energy, which is to be applied to a DNA molecule for a successful ejection from a carbon nanotube, is investigated based on a study on the friction and binding energy between the DNA molecule and the tube. An effective ejection is realized by subjecting a kinetic energy on the DNA molecule that is larger than the solved critical ejection energy. In addition, the relationship between ejection energies and sizes of DNA molecules and carbon nanotubes is investigated. -- Highlights: ► Report the ejection of DNA molecules from CNTs from interaction energy perspectives. ► Develop a methodology for the critical energy of an effective ejection of a DNA molecule from a CNT. ► Present the relationship between critical ejection energies and sizes of DNA molecules and CNTs. ► Provide a general guidance on the ejection of encapsulated molecules from CNTs.

Rhesus factor modulation of effects of smoking and age on psychomotor performance, intelligence, personality profile, and health in Czech soldiers.

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Jaroslav Flegr

Full Text Available BACKGROUND: Rhesus-positive and rhesus-negative persons differ in the presence-absence of highly immunogenic RhD protein on the erythrocyte membrane. This protein is a component of NH(3 or CO(2 pump whose physiological role is unknown. Several recent studies have shown that RhD positivity protects against effects of latent toxoplasmosis on motor performance and personality. It is not known, however, whether the RhD phenotype modifies exclusively the response of the body to toxoplasmosis or whether it also influences effects of other factors. METHODOLOGY/PRINCIPAL FINDINGS: In the present cohort study, we searched for the effects of age and smoking on performance, intelligence, personality and self-estimated health and wellness in about 3800 draftees. We found that the positive effect of age on performance and intelligence was stronger in RhD-positive soldiers, while the negative effect of smoking on performance and intelligence was of similar size regardless of the RhD phenotype. The effect of age on four Cattell's personality factors, i.e., dominance (E, radicalism (Q(1, self-sentiment integration (Q(3, and ergic tension (Q(4, and on Cloninger's factor reward dependency (RD was stronger for RhD-negative than RhD-positive subjects, while the effect of smoking on the number of viral and bacterial diseases was about three times stronger for RhD-negative than RhD-positive subjects. CONCLUSIONS: RhD phenotype modulates the influence not only of latent toxoplasmosis, but also of at least two other potentially detrimental factors, age and smoking, on human behavior and physiology. The negative effect of smoking on health (estimated on the basis of the self-rated number of common viral and bacterial diseases in the past year was much stronger in RhD-negative than RhD-positive subjects. It is critically needed to confirm the differences in health response to smoking between RhD-positive and RhD-negative subjects by objective medical examination in

Effect of auditory feedback differs according to side of hemiparesis: a comparative pilot study

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Bensmail Djamel

2009-12-01

Full Text Available Abstract Background Following stroke, patients frequently demonstrate loss of motor control and function and altered kinematic parameters of reaching movements. Feedback is an essential component of rehabilitation and auditory feedback of kinematic parameters may be a useful tool for rehabilitation of reaching movements at the impairment level. The aim of this study was to investigate the effect of 2 types of auditory feedback on the kinematics of reaching movements in hemiparetic stroke patients and to compare differences between patients with right (RHD and left hemisphere damage (LHD. Methods 10 healthy controls, 8 stroke patients with LHD and 8 with RHD were included. Patient groups had similar levels of upper limb function. Two types of auditory feedback (spatial and simple were developed and provided online during reaching movements to 9 targets in the workspace. Kinematics of the upper limb were recorded with an electromagnetic system. Kinematics were compared between groups (Mann Whitney test and the effect of auditory feedback on kinematics was tested within each patient group (Friedman test. Results In the patient groups, peak hand velocity was lower, the number of velocity peaks was higher and movements were more curved than in the healthy group. Despite having a similar clinical level, kinematics differed between LHD and RHD groups. Peak velocity was similar but LHD patients had fewer velocity peaks and less curved movements than RHD patients. The addition of auditory feedback improved the curvature index in patients with RHD and deteriorated peak velocity, the number of velocity peaks and curvature index in LHD patients. No difference between types of feedback was found in either patient group. Conclusion In stroke patients, side of lesion should be considered when examining arm reaching kinematics. Further studies are necessary to evaluate differences in responses to auditory feedback between patients with lesions in opposite

Cost-effectiveness of the management of rh-negative pregnant women.

Science.gov (United States)

Duplantie, Julie; Gonzales, Odilon Martinez; Bois, Antoine; Nshimyumukiza, Léon; Gekas, Jean; Bujold, Emmanuel; Morin, Valérie; Vallée, Maud; Giguère, Yves; Gagné, Christian; Rousseau, François; Reinharz, Daniel

2013-08-01

The purpose of this study was to determine the most cost-effective option to prevent alloimmunization against the Rh factor. A virtual population of Rh-negative pregnant women in Quebec was built to simulate the cost-effectiveness of preventing alloimmunization. The model considered four options: (1) systematic use of anti-D immunoglobulin; (2) fetal Rh(D) genotyping; (3) immunological determination of the father's Rh type; (4) mixed screening: immunological determination of the father's Rh type, followed if positive by fetal Rh(D) genotyping. Two outcomes were considered, in addition to the estimated costs: (1) the number of babies without hemolytic disease, and (2) the number of surviving infants. In a first pregnancy, two options emerged as the most cost-effective options: systematic prophylaxis and immunological Rh typing of the father, with overlapping confidence intervals between them. In a second pregnancy, the results were similar. In all cases (first or second pregnancy or a combination of the two) fetal genotyping was not found to be a cost-effective option. Routine prophylaxis and immunological Rh typing of the father are the most cost-effective options for the prevention of Rh alloimmunization. Considering that immunological typing of the father would probably not be carried out by the majority of clinicians, routine prophylaxis remains the preferred option. However, this could change if the cost of Rh(D) fetal genotyping fell below $140 per sample.

Possible interaction between myxomatosis and calicivirosis related to rabbit haemorrhagic disease affecting the European rabbit.

Science.gov (United States)

Marchandeau, S; Bertagnoli, S; Peralta, B; Boucraut-Baralon, C; Letty, J; Reitz, F

2004-11-06

Serological data on myxoma virus, rabbit haemorrhagic disease (RHD) virus and RHD-like viruses in juvenile rabbits (Oryctolagus cuniculus) trapped in 1995, 1996 and 1997 in two areas of France were analysed. For each disease, the effects of bodyweight, year, month and seropositivity for the other disease were modelled by using logistic regressions. In one area, a model including RHD seropositivity was selected to explain the myxoma virus seropositivity. Models including myxoma virus seropositivity were selected to explain the RHD seropositivity in both areas, and the odds of a rabbit being seropositive to both viruses were 5.1 and 8.4 times higher than the odds of a rabbit being seronegative to myxoma virus and seropositive to RHD. The year and bodyweight had significant effects for myxomatosis in one area and for RHD in both areas.

Effect of organic molecules on hydrolysis of peptide bond: A DFT study

International Nuclear Information System (INIS)

Makshakova, Olga; Ermakova, Elena

2013-01-01

Highlights: ► DFT study of the effects of small organic molecules on the hydrolysis reactions of peptide bonds. ► Organic molecules can activate nonenzymatic hydrolysis reaction. ► Influence of organic acids on activation energy barrier correlates with their electronegativity. - Abstract: The activation and inhibition effects of small organic molecules on peptide hydrolysis have been studied using a model compound dialanine and DFT approach. Solvent-assisted and non-assisted concerted mechanisms were analyzed. Several transition states for the systems: alanine dipeptide–water molecule in complexes with alcohol molecules, acetonitrile, dimethylsulfoxide, propionic, lactic and pyruvic acids and water molecules were localized. The formation of hydrogen bonds between dipeptide, reactive water molecule and molecules of solvents influences the activation energy barrier of the peptide bond hydrolytic reaction. Strong effect of organic acids on the activation energy barrier correlates with their electronegativity. Acetonitrile can act as an inhibitor of reaction. Mechanisms of regulation of the activation energy barrier are discussed in the terms of donor-acceptor interactions

Kondo effect in single-molecule magnet transistors

Science.gov (United States)

Gonzalez, Gabriel; Leuenberger, Michael; Mucciolo, Eduardo

2009-03-01

We present a careful and thorough microscopic derivation of the anisotropic Kondo Hamiltonian for single-molecule magnet (SMM) transistors. When the molecule is strongly coupled to metallic leads, we show that by applying a transverse magnetic field it is possible to topologically induce or quench the Kondo effect in the conductance of a SMM with either an integer or a half-integer spin S>1/2. This topological Kondo effect is due to the Berry-phase interference between multiple quantum tunneling paths of the spin. We calculate the renormalized Berry-phase oscillations of the two Kondo peaks as a function of a transverse magnetic field by means of the poor man's scaling approach. We illustrate our findings with the SMM Ni4, which we propose as a possible candidate for the experimental observation of the conductance oscillations.

Handheld echocardiography versus auscultation for detection of rheumatic heart disease.

Science.gov (United States)

Godown, Justin; Lu, Jimmy C; Beaton, Andrea; Sable, Craig; Mirembe, Grace; Sanya, Richard; Aliku, Twalib; Yu, Sunkyung; Lwabi, Peter; Webb, Catherine L; Ensing, Gregory J

2015-04-01

Rheumatic heart disease (RHD) remains a major public health concern in developing countries, and routine screening has the potential to improve outcomes. Standard portable echocardiography (STAND) is far more sensitive than auscultation for the detection of RHD but remains cost-prohibitive in resource-limited settings. Handheld echocardiography (HAND) is a lower-cost alternative. The purpose of this study was to assess the incremental value of HAND over auscultation to identify RHD. RHD screening was completed for schoolchildren in Gulu, Uganda, by using STAND performed by experienced echocardiographers. Any child with mitral or aortic regurgitation or stenosis plus a randomly selected group of children with normal STAND findings underwent HAND and auscultation. STAND and HAND studies were interpreted by 6 experienced cardiologists using the 2012 World Heart Federation criteria. Sensitivity and specificity of HAND and auscultation for the detection of RHD and pathologic mitral or aortic regurgitation were calculated by using STAND as the gold standard. Of 4773 children who underwent screening with STAND, a subgroup of 1317 children underwent HAND and auscultation. Auscultation had uniformly poor sensitivity for the detection of RHD or valve disease. Sensitivity was significantly improved by using HAND compared with auscultation for the detection of definite RHD (97.8% vs 22.2%), borderline or definite RHD (78.4% vs 16.4%), and pathologic aortic insufficiency (81.8% vs 13.6%). Auscultation alone is a poor screening test for RHD. HAND significantly improves detection of RHD and may be a cost-effective screening strategy for RHD in resource-limited settings. Copyright © 2015 by the American Academy of Pediatrics.

Echocardiographic screening for subclinical rheumatic heart disease remains a research tool pending studies of impact on prognosis.

Science.gov (United States)

Zühlke, Liesl; Mayosi, Bongani M

2013-03-01

The application of portable echocardiography to the screening of asymptomatic children and young adults for rheumatic heart disease (RHD) in developing countries indicates that the disease may affect 62 million to 78 million individuals worldwide, which could potentially result in 1.4 million deaths per year from RHD and its complications. The World Heart Federation has developed a guideline for the echocardiographic diagnosis of RHD in asymptomatic individuals without a history of acute rheumatic fever (ARF) in order to ensure the reliability, comparability, and reproducibility of findings of the echocardiographic screening studies. Early studies suggest that a third of individuals with asymptomatic subclinical RHD revert to normal echocardiographic findings on repeat testing after 6-12 months, suggesting that repeat echocardiography may be necessary to confirm the findings prior to consideration of interventions such as antibiotic prophylaxis. It is not known, however, whether echocardiographic screening for asymptomatic subclinical RHD or the introduction of antibiotic prophylaxis for affected individuals improves the prognosis of RHD. Furthermore, the cost-effectiveness of this screening method has not been established in the vast majority of affected countries. Therefore, echocardiographic screening for asymptomatic subclinical RHD remains a research tool until studies of impact on prognosis and cost-effectiveness are conducted.

Quantum interference effects at room temperature in OPV-based single-molecule junctions

DEFF Research Database (Denmark)

Arroyo, Carlos R.; Frisenda, Riccardo; Moth-Poulsen, Kasper

2013-01-01

Interference effects on charge transport through an individual molecule can lead to a notable modulation and suppression on its conductance. In this letter, we report the observation of quantum interference effects occurring at room temperature in single-molecule junctions based on oligo(3......)-phenylenevinylene (OPV3) derivatives, in which the central benzene ring is coupled to either para- or meta-positions. Using the break-junction technique, we find that the conductance for a single meta-OPV3 molecule wired between gold electrodes is one order of magnitude smaller than that of a para-OPV3 molecule...

Electronic structure of molecules using relativistic effective core potentials

International Nuclear Information System (INIS)

Hay, P.J.

1981-01-01

Starting with one-component Cowan-Griffin relativistic Hartree-Fock orbitals, which successfully incorporate the mass-velocity and Darwin terms present in more complicated wavefunctions such as Dirac-Hartree-Fock, one can derive relativistic effective core potentials (RECP's) to carry out molecular calculations. These potentials implicitly include the dominant relativistic terms for molecules while allowing one to use the traditional quantum chemical techniques for studying the electronic structure of molecules. The effects of spin-orbit coupling can then be included using orbitals from such calculations using an effective 1-electron, 1-center spin-orbit operator. Applications to molecular systems involving heavy atoms, show good agreement with available spectroscopic data on molecular geometries and excitation energies

Stereoelectronic Effect-Induced Conductance Switching in Aromatic Chain Single-Molecule Junctions.

Science.gov (United States)

Xin, Na; Wang, Jinying; Jia, Chuancheng; Liu, Zitong; Zhang, Xisha; Yu, Chenmin; Li, Mingliang; Wang, Shuopei; Gong, Yao; Sun, Hantao; Zhang, Guanxin; Liu, Zhirong; Zhang, Guangyu; Liao, Jianhui; Zhang, Deqing; Guo, Xuefeng

2017-02-08

Biphenyl, as the elementary unit of organic functional materials, has been widely used in electronic and optoelectronic devices. However, over decades little has been fundamentally understood regarding how the intramolecular conformation of biphenyl dynamically affects its transport properties at the single-molecule level. Here, we establish the stereoelectronic effect of biphenyl on its electrical conductance based on the platform of graphene-molecule single-molecule junctions, where a specifically designed hexaphenyl aromatic chain molecule is covalently sandwiched between nanogapped graphene point contacts to create stable single-molecule junctions. Both theoretical and temperature-dependent experimental results consistently demonstrate that phenyl twisting in the aromatic chain molecule produces different microstates with different degrees of conjugation, thus leading to stochastic switching between high- and low-conductance states. These investigations offer new molecular design insights into building functional single-molecule electrical devices.

Effect of deuteration on the vibrational spectra of organic molecules

International Nuclear Information System (INIS)

Billes, Ferenc; Endredi, Henrietta; Varady, Balazs

2001-01-01

The stable isotope substitution of organic compounds deforms their vibrational spectra. The modifications of the spectra appear as band shifts and changes in intensities and shapes of the bands. The magnitude of the effect depends on the ratio of the masses of the new and old isotopes and on the atom active position. According to these mentioned reasons large effects can be observed only if hydrogen atoms are substituted. With the effect of the substitution we dealt already in a former lecture. In this lecture we concentrate on the effect of the change of hydrogen to deuterium. We investigate the changes both experimentally and theoretically. There are two possibilities: - the hydrogen atom is in an active position, its interaction with the environment is strong, either it can dissociate or move on the skeleton of the molecule (tautomerism, resonance) and it can build hydrogen bond, (e.g. it is connected to nitrogen and oxygen atoms); - the hydrogen atom is in an indifferent position in the molecule, its interaction with the environment is weak (e.g. it joins carbon atom). When building the hydrogen bond besides the hydrogen donors also acceptors exist, namely, oxygen and nitrogen atoms having non-bonded electron pairs. When comparing the experimental and theoretical (calculated) effects of this type of isotope changes one must take into account that the calculations refer to the isolated molecule while the experimental spectra characterize the compound. The hydrogen bond is a very strong intermolecular interaction and produces tremendous changes in the infrared spectrum of the molecule in comparison to the imagined theoretical spectrum of the molecule. Some bands disappear, appear, or shift and deform drastically. The H/D change diminishes these effects. Of course, these changes entail the shift of several bands. The Raman spectrum is less sensitive to the large dipole moment changes therefore the deuteration effect is there less dramatic. Deuteration of hydrogen

Women's attitude towards prenatal screening for red blood cell antibodies, other than RhD

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van der Schoot CE

2008-11-01

Full Text Available Abstract Background Since July 1998 all Dutch women (± 200,000/y are screened for red cell antibodies, other than anti-RhesusD (RhD in the first trimester of pregnancy, to facilitate timely treatment of pregnancies at risk for hemolytic disease of the fetus and newborn (HDFN. Evidence for benefits, consequences and costs of screening for non-RhD antibodies is still under discussion. The screening program was evaluated in a nation-wide study. As a part of this evaluation study we investigated, according to the sixth criterium of Wilson and Jüngner, the acceptance by pregnant women of the screening program for non-RhD antibodies. Methods Controlled longitudinal survey, including a prenatal and a postnatal measurement by structured questionnaires. Main outcome measures: information satisfaction, anxiety during the screening process (a.o. STAI state inventory and specific questionnaire modules, overall attitude on the screening program. Univariate analysis was followed by standard multivariate analysis to identify significant predictors of the outcome measures. Participants: 233 pregnant women, distributed over five groups, according to the screening result. Results Satisfaction about the provided information was moderate in all groups. All screen- positive groups desired more supportive information. Anxiety increased in screen- positives during the screening process, but decreased to basic levels postnatally. All groups showed a strongly positive balance between perceived utility and burden of the screening program, independent on test results or background characteristics. Conclusion Women highly accept the non-RhD antibody screening program. However, satisfaction about provided information is moderate. Oral and written information should be provided by obstetric care workers themselves, especially to screen-positive women.

Blinking effect and the use of quantum dots in single molecule spectroscopy

International Nuclear Information System (INIS)

Rombach-Riegraf, Verena; Oswald, Peter; Bienert, Roland; Petersen, Jan; Domingo, M.P.; Pardo, Julian; Gräber, P.; Galvez, E.M.

2013-01-01

Highlights: ► It is possible to eliminate the blinking effect of a water-soluble QD. ► We provide a direct method to study protein function and dynamics at the single level. ► QD, potent tool for single molecule studies of biochemical and biological processes. -- Abstract: Luminescent semiconductor nanocrystals (quantum dots, QD) have unique photo-physical properties: high photostability, brightness and narrow size-tunable fluorescence spectra. Due to their unique properties, QD-based single molecule studies have become increasingly more popular during the last years. However QDs show a strong blinking effect (random and intermittent light emission), which may limit their use in single molecule fluorescence studies. QD blinking has been widely studied and some hypotheses have been done to explain this effect. Here we summarise what is known about the blinking effect in QDs, how this phenomenon may affect single molecule studies and, on the other hand, how the “on”/“off” states can be exploited in diverse experimental settings. In addition, we present results showing that site-directed binding of QD to cysteine residues of proteins reduces the blinking effect. This option opens a new possibility of using QDs to study protein–protein interactions and dynamics by single molecule fluorescence without modifying the chemical composition of the solution or the QD surface.

Blinking effect and the use of quantum dots in single molecule spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Rombach-Riegraf, Verena; Oswald, Peter; Bienert, Roland; Petersen, Jan [Albert-Ludwigs-Universitaet Freiburg, Institut fuer Physikalische Chemie, Albertstrasse 23a, 79104 Freiburg (Germany); Domingo, M.P. [Instituto de Carboquimica (CSIC), Miguel Luesma 4, 50018 Zaragoza (Spain); Pardo, Julian [Grupo Apoptosis, Inmunidad y Cancer, Departamento Bioquimica y Biologia Molecular y Celular, Fac. Ciencias, Universidad de Zaragoza, Zaragoza (Spain); Fundacion Aragon I-D (ARAID), Gobierno de Aragon, Zaragoza (Spain); Immune Effector Cells Group, Aragon Health Research Institute (IIS Aragon), Biomedical Research Centre of Aragon (CIBA) Fundacion Aragon I-D - ARAID, Gobierno de Aragon, Zaragoza (Spain); Graeber, P. [Albert-Ludwigs-Universitaet Freiburg, Institut fuer Physikalische Chemie, Albertstrasse 23a, 79104 Freiburg (Germany); Galvez, E.M., E-mail: eva@icb.csic.es [Instituto de Carboquimica (CSIC), Miguel Luesma 4, 50018 Zaragoza (Spain); Immune Effector Cells Group, Aragon Health Research Institute (IIS Aragon), Biomedical Research Centre of Aragon (CIBA) Fundacion Aragon I-D - ARAID, Gobierno de Aragon, Zaragoza (Spain)

2013-01-04

Highlights: Black-Right-Pointing-Pointer It is possible to eliminate the blinking effect of a water-soluble QD. Black-Right-Pointing-Pointer We provide a direct method to study protein function and dynamics at the single level. Black-Right-Pointing-Pointer QD, potent tool for single molecule studies of biochemical and biological processes. -- Abstract: Luminescent semiconductor nanocrystals (quantum dots, QD) have unique photo-physical properties: high photostability, brightness and narrow size-tunable fluorescence spectra. Due to their unique properties, QD-based single molecule studies have become increasingly more popular during the last years. However QDs show a strong blinking effect (random and intermittent light emission), which may limit their use in single molecule fluorescence studies. QD blinking has been widely studied and some hypotheses have been done to explain this effect. Here we summarise what is known about the blinking effect in QDs, how this phenomenon may affect single molecule studies and, on the other hand, how the 'on'/'off' states can be exploited in diverse experimental settings. In addition, we present results showing that site-directed binding of QD to cysteine residues of proteins reduces the blinking effect. This option opens a new possibility of using QDs to study protein-protein interactions and dynamics by single molecule fluorescence without modifying the chemical composition of the solution or the QD surface.

Environmental effects on molecules immersed in liquids

International Nuclear Information System (INIS)

Sese, L.M.

1990-01-01

A methodology to study environmental effects is thoroughly discussed. It combines molecular quantum mechanics and classical statistical mechanics of molecular fluids. Pair distribution functions collecting statistical information appear quite naturally in the quantum equations describing a single molecule. As well as allowing the computation of any individual molecular property in a liquid phase, this approach satisfies a number of theoretical requirements (dependence on density and temperature, validity in the thermodynamic limit). In a sense, it can be regarded as a useful alternative to the well-known Monte Carlo averaging processes for calculating molecular properties. Numerical applications studying liquid carbon disulphide and liquid carbon tetrachloride at several state points are given. Results cover typical RHF information (CNDO/2) on molecules, and show the sensitivity of the presented methodology to structural changes in liquids. (orig.)

Effect of dipole polarizability on positron binding by strongly polar molecules

International Nuclear Information System (INIS)

Gribakin, G F; Swann, A R

2015-01-01

A model for positron binding to polar molecules is considered by combining the dipole potential outside the molecule with a strongly repulsive core of a given radius. Using existing experimental data on binding energies leads to unphysically small core radii for all of the molecules studied. This suggests that electron–positron correlations neglected in the simple model play a large role in determining the binding energy. We account for these by including the polarization potential via perturbation theory and non-perturbatively. The perturbative model makes reliable predictions of binding energies for a range of polar organic molecules and hydrogen cyanide. The model also agrees with the linear dependence of the binding energies on the polarizability inferred from the experimental data (Danielson et al 2009 J. Phys. B: At. Mol. Opt. Phys. 42 235203). The effective core radii, however, remain unphysically small for most molecules. Treating molecular polarization non-perturbatively leads to physically meaningful core radii for all of the molecules studied and enables even more accurate predictions of binding energies to be made for nearly all of the molecules considered. (paper)

Global research priorities in rheumatic fever and rheumatic heart disease

International Nuclear Information System (INIS)

Carapetis, Jonathan R; Zühlke, Liesl J

2011-01-01

We now stand at a critical juncture for rheumatic fever (RF) and rheumatic heart disease (RHD) control. In recent years, we have seen a surge of interest in these diseases in regions of the world where RF/RHD mostly occur. This brings real opportunities to make dramatic progress in the next few years, but also real risks if we miss these opportunities. Most public health and clinical approaches in RF/RHD arose directly from programmes of research. Many unanswered questions remain, including those around how to implement what we know will work, so research will continue to be essential in our efforts to bring a global solution to this disease. Here we outline our proposed research priorities in RF/RHD for the coming decade, grouped under the following four challenges: Translating what we know already into practical RHD control; How to identify people with RHD earlier, so that preventive measures have a higher chance of success; Better understanding of disease pathogenesis, with a view to improved diagnosis and treatment of ARF and RHD; and Finding an effective approach to primary prevention. We propose a mixture of basic, applied, and implementation science. With concerted efforts, strong links to clinical and public health infrastructure, and advocacy and funding support from the international community, there are good prospects for controlling these RF and RHD over the next decade

Frequency of ABO blood groups and RhD factor in the female population of District Peshawar.

Science.gov (United States)

Nazli, Rubina; Haider, Jamila; Khan, Mohammad Akmal; Akhtar, Tasleem; Aslam, Hina

2015-01-01

To determine the frequency of ABO blood group and Rhesus (Rh) D antigen in the females of "District" Peshawar, Khyber Pakhtunkhwa Province, Pakistan. This cross-sectional study was conducted on 429 women having pregnancy induced hypertension, admitted in the three teaching hospitals of Peshawar, over a period of one year. Blood sample was collected from each subject after taking informed consent. The antigen antibody agglutination slide test for "blood grouping (ABO)" and RhD factors was done by using IgM and IgG monoclonal reagents. The antisera used were from Biolaboratory, USA. Data was analyzed for percentage calculation. The blood group distribution was 134 (31.2%), 43 (10.1%), 116 (27%), 136 (31.7%) for blood groups A, AB, O and B, respectively. Subjects having blood group B was slightly more dominant, followed by A and O, while blood group AB was rare in these females. Blood group A Rh negative is more in female 12 (37.5%) followed by group O 10 (31.3%), group B 09 (28.1%) and group AB 01 (3.1%). Frequency of "Rh-positive blood group" is B, A, O and AB, whereas the frequency of the most common Rh-negative blood group are A, O, B and AB respectively. The determination of the frequency of blood groups in the region would not only help in blood transfusion services, but also reduce the risk of erythroblastosis foetalis in the neonates.

Effects of molecular orientation in the laser ionization of molecules

International Nuclear Information System (INIS)

Xinhua Xie; Gerald Jordan; Christopher Ede; Armin Scrinzi

2006-01-01

Complete test of publication follows. Time-dependent electron momentum distributions are calculated during ionization of linear molecules by a strong laser pulse and upon recollision. For typical experimental laser parameters, we find a strong influence of molecular orientation and initial state symmetry on the total ionization rates and also on momentum distributions, compared to which the effect of electron correlation is less important for simple molecules. The dynamics of electron release and subsequent recollision with the parent ion largely determines the time-frequency structure of harmonic radiation, which underlies the generation of attosecond XUV pulses and the time-resolved imaging techniques for the electronic structure of molecules. In the present work, the effects of orientation and initial orbital symmetry are investigated by solving the time-dependent Schroedinger equation for a two-dimensional diatomic molecule in the single-active electron approximation. As in the presence of strong external fields recolliding electrons cannot be easily separated from bound electrons, the electron wave packet is probed at some distance from where all electrons can be safety considered as detached. We find that momentum distributions strongly depend on molecular size, orientation of the molecular axis, and node structure of the initial state. In order to determine the momentum spectra at the time of electron release and upon recollision, we classically propagate the Wigner distributions of probed wavepackets backward and forward in time, respectively. We find that the times of peak recollision current can vary strongly with the orientation of the molecule. Moreover, correlation effects on the electron spectra are included using the multi-configuration time-dependent Hartree-Fock method. The calculations are performed in three spatial dimensions with the restriction to cylindrical symmetry, where the molecule is aligned with the laser field. Correlation is studied

Effect of oscillation mode on the free-molecule squeeze-film air damping

KAUST Repository

Gang Hong,; Wenjing Ye,

2010-01-01

A 3D Monte Carlo (MC) simulation approach is developed and employed to study the effect of the oscillation mode on the squeeze-film air damping in the free-molecule regime. By tracking individual gas molecule's motion and its interaction

Formation of Ultracold Molecules

Energy Technology Data Exchange (ETDEWEB)

Cote, Robin [Univ. of Connecticut, Storrs, CT (United States)

2016-01-28

Advances in our ability to slow down and cool atoms and molecules to ultracold temperatures have paved the way to a revolution in basic research on molecules. Ultracold molecules are sensitive of very weak interactions, even when separated by large distances, which allow studies of the effect of those interactions on the behavior of molecules. In this program, we have explored ways to form ultracold molecules starting from pairs of atoms that have already reached the ultracold regime. We devised methods that enhance the efficiency of ultracold molecule production, for example by tuning external magnetic fields and using appropriate laser excitations. We also investigates the properties of those ultracold molecules, especially their de-excitation into stable molecules. We studied the possibility of creating new classes of ultra-long range molecules, named macrodimers, thousand times more extended than regular molecules. Again, such objects are possible because ultra low temperatures prevent their breakup by collision. Finally, we carried out calculations on how chemical reactions are affected and modified at ultracold temperatures. Normally, reactions become less effective as the temperature decreases, but at ultracold temperatures, they can become very effective. We studied this counter-intuitive behavior for benchmark chemical reactions involving molecular hydrogen.

Magnetic field modification of ultracold molecule-molecule collisions

International Nuclear Information System (INIS)

Tscherbul, T V; Suleimanov, Yu V; Aquilanti, V; Krems, R V

2009-01-01

We present an accurate quantum mechanical study of molecule-molecule collisions in the presence of a magnetic field. The work focuses on the analysis of elastic scattering and spin relaxation in collisions of O 2 ( 3 Σ g - ) molecules at cold (∼0.1 K) and ultracold (∼10 -6 K) temperatures. Our calculations show that magnetic spin relaxation in molecule-molecule collisions is extremely efficient except at magnetic fields below 1 mT. The rate constant for spin relaxation at T=0.1 K and a magnetic field of 0.1 T is found to be as large as 6.1x10 -11 cm -3 s -1 . The magnetic field dependence of elastic and inelastic scattering cross sections at ultracold temperatures is dominated by a manifold of Feshbach resonances with the density of ∼100 resonances per Tesla for collisions of molecules in the absolute ground state. This suggests that the scattering length of ultracold molecules in the absolute ground state can be effectively tuned in a very wide range of magnetic fields. Our calculations demonstrate that the number and properties of the magnetic Feshbach resonances are dramatically different for molecules in the absolute ground and excited spin states. The density of Feshbach resonances for molecule-molecule scattering in the low-field-seeking Zeeman state is reduced by a factor of 10.

Revealing time bunching effect in single-molecule enzyme conformational dynamics.

Science.gov (United States)

Lu, H Peter

2011-04-21

In this perspective, we focus our discussion on how the single-molecule spectroscopy and statistical analysis are able to reveal enzyme hidden properties, taking the study of T4 lysozyme as an example. Protein conformational fluctuations and dynamics play a crucial role in biomolecular functions, such as in enzymatic reactions. Single-molecule spectroscopy is a powerful approach to analyze protein conformational dynamics under physiological conditions, providing dynamic perspectives on a molecular-level understanding of protein structure-function mechanisms. Using single-molecule fluorescence spectroscopy, we have probed T4 lysozyme conformational motions under the hydrolysis reaction of a polysaccharide of E. coli B cell walls by monitoring the fluorescence resonant energy transfer (FRET) between a donor-acceptor probe pair tethered to T4 lysozyme domains involving open-close hinge-bending motions. Based on the single-molecule spectroscopic results, molecular dynamics simulation, a random walk model analysis, and a novel 2D statistical correlation analysis, we have revealed a time bunching effect in protein conformational motion dynamics that is critical to enzymatic functions. Bunching effect implies that conformational motion times tend to bunch in a finite and narrow time window. We show that convoluted multiple Poisson rate processes give rise to the bunching effect in the enzymatic reaction dynamics. Evidently, the bunching effect is likely common in protein conformational dynamics involving in conformation-gated protein functions. In this perspective, we will also discuss a new approach of 2D regional correlation analysis capable of analyzing fluctuation dynamics of complex multiple correlated and anti-correlated fluctuations under a non-correlated noise background. Using this new method, we are able to map out any defined segments along the fluctuation trajectories and determine whether they are correlated, anti-correlated, or non-correlated; after which, a

Detecting high-density ultracold molecules using atom–molecule collision

International Nuclear Information System (INIS)

Chen, Jun-Ren; Kao, Cheng-Yang; Chen, Hung-Bin; Liu, Yi-Wei

2013-01-01

Utilizing single-photon photoassociation, we have achieved ultracold rubidium molecules with a high number density that provides a new efficient approach toward molecular quantum degeneracy. A new detection mechanism for ultracold molecules utilizing inelastic atom–molecule collision is demonstrated. The resonant coupling effect on the formation of the X 1 Σ + g ground state 85 Rb 2 allows for a sufficient number of more deeply bound ultracold molecules, which induced an additional trap loss and heating of the co-existing atoms owing to the inelastic atom–molecule collision. Therefore, after the photoassociation process, the ultracold molecules can be investigated using the absorption image of the ultracold rubidium atoms mixed with the molecules in a crossed optical dipole trap. The existence of the ultracold molecules was then verified, and the amount of accumulated molecules was measured. This method detects the final produced ultracold molecules, and hence is distinct from the conventional trap loss experiment, which is used to study the association resonance. It is composed of measurements of the time evolution of an atomic cloud and a decay model, by which the number density of the ultracold 85 Rb 2 molecules in the optical trap was estimated to be >5.2 × 10 11 cm −3 . (paper)

Influence of the effective mass of water molecule on thermal neutron scattering

International Nuclear Information System (INIS)

Markovic, M.

1981-01-01

The influence of the effective water molecule mass on the thermal neutron scattering on the nucleus of the hydrogen atom has been investigated. Besides the actual water molecule mass (M = 18) the investigations have been carried out with its two effective values (M1 = 16 and M2 = 20). The differential and total cross sections have been calculated for the incident thermal neutron energy E o = 1 eV. Investigation results show different prominence of the quantum effects and for M2 the appearance of peaks in the quasielastic scattering. (author)

Emergency transfusion of patients with unknown blood type with blood group O Rhesus D positive red blood cell concentrates: a prospective, single-centre, observational study.

Science.gov (United States)

Selleng, Kathleen; Jenichen, Gregor; Denker, Kathrin; Selleng, Sixten; Müllejans, Bernd; Greinacher, Andreas

2017-05-01

Emergency patients with unknown blood type usually receive O Rhesus D negative (RhD-) red blood cell concentrates until their blood group is determined to prevent RhD+ related adverse transfusion reactions. As 85% of individuals are RhD+, this consumption of O RhD- red blood cell concentrates contributes to shortages of O RhD- red blood cell concentrates, sometimes forcing transfusion of known RhD- patients with RhD+ red blood cell concentrates. Here we report the outcome of this transfusion policy transfusing all emergency patients with unknown blood type with O RhD+ red blood cell concentrates. In this prospective single-centre observational study done between Jan 1, 2001, and Dec 31, 2015, we assessed all consecutive RhD- patients at the University Medicine Greifswald who received RhD+ red blood cell concentrates (emergency patients with unknown blood type; and RhD- patients receiving RhD+ red blood cell concentrates during RhD- red blood cell concentrate shortages). No patients were excluded. The primary endpoint was anti-D allo-immunisation at 2 months follow-up or later. Patients were followed up and tested for immunisation against red blood cell antigens using the direct antiglobulin test and an antibody screen every 3-5 days for 4 weeks or until death, or hospital discharge. Surviving patients were screened for development of anti-D antibodies for up to 12 months (at the predefined timepoints 2, 3, 6, and 12 months) after RhD+ red blood cell transfusion. 437 emergency patients, of whom 85 (20%) were RhD-, received 2836 RhD+ red blood cell concentrates. The overall risk of inducing anti-D antibodies (in all 437 recipients) was 17 (4%, 95% CI 2·44-6·14) of 437 (assuming all patients lost to follow-up developed anti-D allo-immunisation). During this period, 110 known RhD- patients received RhD+ red blood cell concentrates during RhD- red blood cell concentrate shortages. Of these, 29 (26%; 95% CI 19·0-35·3) developed anti-D allo-immunisation (assuming all

Acute rheumatic fever and rheumatic heart disease--priorities in prevention, diagnosis and management. A report of the CSANZ Indigenous Cardiovascular Health Conference, Alice Springs 2011.

Science.gov (United States)

Rémond, M G W; Wheaton, G R; Walsh, W F; Prior, D L; Maguire, G P

2012-10-01

Three priority areas in the prevention, diagnosis and management of acute rheumatic fever (ARF) and rheumatic heart disease (RHD) were identified and discussed in detail: 1. Echocardiography and screening/diagnosis of RHD – Given the existing uncertainty it remains premature to advocate for or to incorporate echocardiographic screening for RHD into Australian clinical practice. Further research is currently being undertaken to evaluate the potential for echocardiography screening. 2. Secondary prophylaxis – Secondary prophylaxis (long acting benzathine penicillin injections) must be seen as a priority. Systems-based approaches are necessary with a focus on the development and evaluation of primary health care-based or led strategies incorporating effective health information management systems. Better/novel systems of delivery of prophylactic medications should be investigated. 3. Management of advanced RHD – National centres of excellence for the diagnosis, assessment and surgical management of RHD are required. Early referral for surgical input is necessary with multidisciplinary care and team-based decision making that includes patient, family, and local health providers. There is a need for a national RHD surgical register and research strategy for the assessment, intervention and long-term outcome of surgery and other interventions for RHD. Copyright © 2012 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

Rheumatic heart disease screening: Current concepts and challenges

Science.gov (United States)

Dougherty, Scott; Khorsandi, Maziar; Herbst, Philip

2017-01-01

Rheumatic heart disease (RHD) is a disease of poverty, is almost entirely preventable, and is the most common cardiovascular disease worldwide in those under 25 years. RHD is caused by acute rheumatic fever (ARF) which typically results in cumulative valvular lesions that may present clinically after a number of years of subclinical disease. Therapeutic interventions, therefore, typically focus on preventing subsequent ARF episodes (with penicillin prophylaxis). However, not all patients with ARF develop symptoms and not all symptomatic cases present to a physician or are correctly diagnosed. Therefore, if we hope to control ARF and RHD at the population level, we need a more reliable discriminator of subclinical disease. Recent studies have examined the utility of echocardiographic screening, which is far superior to auscultation at detecting RHD. However, there are many concerns surrounding this approach. Despite the introduction of the World Heart Federation diagnostic criteria in 2012, we still do not really know what constitutes the most subtle changes of RHD by echocardiography. This poses serious problems regarding whom to treat and what to do with the rest, both important decisions with widespread implications for already stretched health-care systems. In addition, issues ranging from improving the uptake of penicillin prophylaxis in ARF/RHD-positive patients, improving portable echocardiographic equipment, understanding the natural history of subclinical RHD and how it might respond to penicillin, and developing simplified diagnostic criteria that can be applied by nonexperts, all need to be effectively tackled before routine widespread screening for RHD can be endorsed. PMID:28163427

Prevention and control of rheumatic heart disease: Overcoming core challenges in resource-poor environments

Science.gov (United States)

Dougherty, Scott; Beaton, Andrea; Nascimento, Bruno R; Zühlke, Liesl J; Khorsandi, Maziar; Wilson, Nigel

2018-01-01

Rheumatic heart disease (RHD) has long receded as a significant threat to public health in high-income countries. In low-resource settings, however, the specter of RHD remains unabated, as exemplified by recent data from the Global Burden of Diseases Study. There are many complex reasons for this ongoing global disparity, including inadequate data on disease burden, challenges in effective advocacy, ongoing poverty and inequality, and weak health systems, most of which predominantly affect developing nations. In this review, we discuss how each of these acts as a core challenge in RHD prevention and control. We then examine key lessons learnt from successful control programs in the past and highlight resources that have been developed to help create strong national RHD control programs. PMID:29440834

Medea genes, handedness and other traits

Science.gov (United States)

Hatfield, Jeffrey

2015-01-01

Medea factors or genes are maternal-effects mechanisms, found in many species, in which the mother's body selectively kills embryos of a certain genotype.Humans have a similar genetic mechanism, the gene RHD which produces Rh-factor involved in blood type.Recently I proposed that RHD acts as a maternal-effects gene that determines handedness (i.e., right handed or non-right handed) in individuals of our species. Here, I argue that RHD functions as a Medea gene as well.The handedness gene (and also RHD itself in some cases) has been implicated in autism spectrum disorders (ASD), bipolar disorder, cerebral laterality (i.e., right-brained or left-brained speech laterality), hair-whorl rotation, schizophrenia, sexual orientation, and speech dyslexia.Identifying the gene or genes that determine handedness or cerebral laterality may help uncover the mechanisms underlying these behavioral phenotypes in our species.A relatively simple test of the handedness hypothesis has been proposed:In a sample of humans for whom handedness has been evaluated, we would need to genotype for RHD by determining whether Rh+ individuals have one or two copies of the dominant allele. If RHD and perhaps also an interaction with RHCE are involved in sexual orientation, it explains how selection could favor a gene or genes which cause some people to become non-heterosexual.The literature on Medea genes provides the explanation:A Medea allele must increase in frequency, sometimes to fixation (i.e., 100% frequency) even if it reduces fecundity (e.g., birth rate).In addition, treatment for RHD maternal-fetal genotype incompatibility, which allows more fetuses to survive to term now, may be one explanation for why ASD appears to be increasing in frequency in some populations, if RHD is indeed the handedness gene, although many other mechanisms have also been suggested. One wonders if bipolar disorder and the other alternative phenotypes are also increasing in frequency.

A cost-effectiveness analysis of a program to control rheumatic fever and rheumatic heart disease in Pinar del Rio, Cuba.

Directory of Open Access Journals (Sweden)

David A Watkins

Full Text Available Acute rheumatic fever (ARF and rheumatic heart disease (RHD persist in many low- and middle-income countries. To date, the cost-effectiveness of population-based, combined primary and secondary prevention strategies has not been assessed. In the Pinar del Rio province of Cuba, a comprehensive ARF/RHD control program was undertaken over 1986-1996. The present study analyzes the cost-effectiveness of this Cuban program.We developed a decision tree model based on the natural history of ARF/RHD, comparing the costs and effectiveness of the 10-year Cuban program to a "do nothing" approach. Our population of interest was the cohort of children aged 5-24 years resident in Pinar del Rio in 1986. We assessed costs and health outcomes over a lifetime horizon, and we took the healthcare system perspective on costs but did not apply a discount rate. We used epidemiologic, clinical, and direct medical cost inputs that were previously collected for publications on the Cuban program. We estimated health gains as disability-adjusted life years (DALYs averted using standard approaches developed for the Global Burden of Disease studies. Cost-effectiveness acceptability thresholds were defined by one and three times per capita gross domestic product per DALY averted. We also conducted an uncertainty analysis using Monte Carlo simulations and several scenario analyses exploring the impact of alternative assumptions about the program's effects and costs. We found that, compared to doing nothing, the Cuban program averted 5051 DALYs (1844 per 100,000 school-aged children and saved $7,848,590 (2010 USD despite a total program cost of $202,890 over 10 years. In the scenario analyses, the program remained cost saving when a lower level of effectiveness and a reduction in averted years of life lost were assumed. In a worst-case scenario including 20-fold higher costs, the program still had a 100% of being cost-effective and an 85% chance of being cost saving.A 10-year

A cost-effectiveness analysis of a program to control rheumatic fever and rheumatic heart disease in Pinar del Rio, Cuba.

Science.gov (United States)

Watkins, David A; Mvundura, Mercy; Nordet, Porfirio; Mayosi, Bongani M

2015-01-01

Acute rheumatic fever (ARF) and rheumatic heart disease (RHD) persist in many low- and middle-income countries. To date, the cost-effectiveness of population-based, combined primary and secondary prevention strategies has not been assessed. In the Pinar del Rio province of Cuba, a comprehensive ARF/RHD control program was undertaken over 1986-1996. The present study analyzes the cost-effectiveness of this Cuban program. We developed a decision tree model based on the natural history of ARF/RHD, comparing the costs and effectiveness of the 10-year Cuban program to a "do nothing" approach. Our population of interest was the cohort of children aged 5-24 years resident in Pinar del Rio in 1986. We assessed costs and health outcomes over a lifetime horizon, and we took the healthcare system perspective on costs but did not apply a discount rate. We used epidemiologic, clinical, and direct medical cost inputs that were previously collected for publications on the Cuban program. We estimated health gains as disability-adjusted life years (DALYs) averted using standard approaches developed for the Global Burden of Disease studies. Cost-effectiveness acceptability thresholds were defined by one and three times per capita gross domestic product per DALY averted. We also conducted an uncertainty analysis using Monte Carlo simulations and several scenario analyses exploring the impact of alternative assumptions about the program's effects and costs. We found that, compared to doing nothing, the Cuban program averted 5051 DALYs (1844 per 100,000 school-aged children) and saved $7,848,590 (2010 USD) despite a total program cost of $202,890 over 10 years. In the scenario analyses, the program remained cost saving when a lower level of effectiveness and a reduction in averted years of life lost were assumed. In a worst-case scenario including 20-fold higher costs, the program still had a 100% of being cost-effective and an 85% chance of being cost saving. A 10-year program to

Influence of thermocleavable functionality on organic field-effect transistor performance of small molecules

Science.gov (United States)

Mahale, Rajashree Y.; Dharmapurikar, Satej S.; Chini, Mrinmoy Kumar; Venugopalan, Vijay

2017-06-01

Diketopyrrolopyrrole based donor-acceptor-donor conjugated small molecules using ethylene dioxythiophene as a donor was synthesized. Electron deficient diketopyrrolopyrrole unit was substituted with thermocleavable (tert-butyl acetate) side chains. The thermal treatment of the molecules at 160 °C eliminated the tert-butyl ester group results in the formation of corresponding acid. Optical and theoretical studies revealed that the molecules adopted a change in molecular arrangement after thermolysis. The conjugated small molecules possessed p-channel charge transport characteristics in organic field effect transistors. The charge carrier mobility was increased after thermolysis of tert-butyl ester group to 5.07 × 10-5 cm2/V s.

School and Community Screening Shows Malawi, Africa, to Have a High Prevalence of Latent Rheumatic Heart Disease.

Science.gov (United States)

Sims Sanyahumbi, Amy; Sable, Craig A; Beaton, Andrea; Chimalizeni, Yamikani; Guffey, Danielle; Hosseinipour, Mina; Karlsten, Melissa; Kazembe, Peter N; Kennedy, Neil; Minard, Charles G; Penny, Daniel J

2016-12-01

Rheumatic heart disease (RHD) is the largest cardiac cause of morbidity and mortality in the world's youth. Early detection of RHD through echocardiographic screening in asymptomatic children may identify an early stage of disease, when secondary prophylaxis has the greatest chance of stopping disease progression. Latent RHD signifies echocardiographic evidence of RHD with no known history of acute rheumatic fever and no clinical symptoms. Determine the prevalence of latent RHD among children ages 5-16 in Lilongwe, Malawi. This is a cross-sectional study in which children ages 5 through 16 were screened for RHD using echocardiography. Screening was conducted in 3 schools and surrounding communities in the Lilongwe district of Malawi between February and April 2014. Children were diagnosed as having no, borderline, or definite RHD as defined by World Heart Federation criteria. The primary reader completed offline reads of all studies. A second reader reviewed all of the studies diagnosed as RHD, plus a selection of normal studies. A third reader served as tiebreaker for discordant diagnoses. The distribution of results was compared between gender, location, and age categories using Fisher's exact test. The prevalence of latent RHD was 3.4% (95% CI = 2.45, 4.31), with 0.7% definite RHD and 2.7% borderline RHD. There was no significant differences in prevalence between gender (P = .44), site (P = .6), urban vs. peri-urban (P = .75), or age (P = .79). Of those with definite RHD, all were diagnosed because of pathologic mitral regurgitation (MR) and 2 morphologic features of the mitral valve. Of those with borderline RHD, most met the criteria by having pathological MR (92.3%). Malawi has a high rate of latent RHD, which is consistent with other results from sub-Saharan Africa. This study strongly supports the need for a RHD prevention and control program in Malawi. © 2016 Wiley Periodicals, Inc.

Rheumatic Heart Disease in the Twenty-First Century.

Science.gov (United States)

Woldu, Bethel; Bloomfield, Gerald S

2016-10-01

Rheumatic heart disease (RHD) is a chronic valvular disease resulting after severe or repetitive episodes of acute rheumatic fever (ARF), an autoimmune response to group A Streptococcus infection. RHD has been almost eliminated with improved social and health infrastructure in affluent countries while it remains a neglected disease with major cause of morbidity and mortality in many low- and middle-income countries, and resource-limited regions of high-income countries. Despite our evolving understanding of the pathogenesis of RHD, there have not been any significant advances to prevent or halt progression of disease in recent history. Long-term penicillin-based treatment and surgery remain the backbone of a RHD control program in the absence of an effective vaccine. The advent of echocardiographic screening algorithms has improved the accuracy of diagnosing RHD and has shed light on the enormous burden of disease. Encouragingly, this has led to a rekindled commitment from researchers in the most affected countries to advocate and take bold actions to end this disease of social inequality.

Effect of oscillation mode on the free-molecule squeeze-film air damping

KAUST Repository

Gang Hong,

2010-01-01

A 3D Monte Carlo (MC) simulation approach is developed and employed to study the effect of the oscillation mode on the squeeze-film air damping in the free-molecule regime. By tracking individual gas molecule\\'s motion and its interaction with the resonator, the MC approach is by far the most accurate modeling approach for the modeling of squeeze-film damping in the free-molecule regime. The accuracy of this approach is demonstrated on several cases in which either analytical solutions or experimental measurements are available. It has been found that unlike the case when resonators oscillate in an unbounded domain, squeeze film damping is very sensitive to the mode shape, which implies that some of the existing modeling approaches based on rigid-resonator assumption may not be accurate when applied to model resonators oscillating at their deformed shape. ©2010 IEEE.

Observation of Resonant Effects in Ultracold Collisions between Heteronuclear Feshbach Molecules

Science.gov (United States)

Ye, Xin; Wang, Fudong; Zhu, Bing; Guo, Mingyang; Lu, Bo; Wang, Dajun

2016-05-01

Magnetic field dependent dimer-dimer collisional losses are studied with ultracold 23 Na87 Rb Feshbach molecules. By ramping the magnetic field across the 347.8 G inter-species Feshbach resonance and removing residual atoms with a magnetic field gradient, ~ 8000 pure NaRb Feshbach molecules with a temperature below 1 μK are produced. By holding the pure molecule sample in a crossed optical dipole trap and measuring the time-dependent loss curves under different magnetic fields near the Feshbach resonance, the dimer-dimer loss rates with respect to the atomic scattering length a are mapped out. We observe a resonant feature at around a = 600a0 and a rising tail at above a = 1600a0 . This behavior resembles previous theoretical works on homonuclear Feshbach molecule, where resonant effects between dimer-dimer collisions tied to tetramer bound states were predicted. Our work shows the possibility of exploring four-body physics within a heteronuclear system. We are supported by Hong Kong RGC General Research Fund no. CUHK403813.

Electronic structure of molecules using relativistic effective core potentials

International Nuclear Information System (INIS)

Hay, P.J.

1983-01-01

In this review an approach is outlined for studying molecules containing heavy atoms with the use of relativistic effective core potentials (RECP's). These potentials play the dual roles of (1) replacing the chemically-inert core electrons and (2) incorporating the mass velocity and Darwin term into a one-electron effective potential. This reduces the problem to a valence-electron problem and avoids computation of additional matrix elements involving relativistic operators. The spin-orbit effects are subsequently included using the molecular orbitals derived from the RECP calculation as a basis

Electron-excited molecule interactions

International Nuclear Information System (INIS)

Christophorou, L.G.; Tennessee Univ., Knoxville, TN

1991-01-01

In this paper the limited but significant knowledge to date on electron scattering from vibrationally/rotationally excited molecules and electron scattering from and electron impact ionization of electronically excited molecules is briefly summarized and discussed. The profound effects of the internal energy content of a molecule on its electron attachment properties are highlighted focusing in particular on electron attachment to vibrationally/rotationally and to electronically excited molecules. The limited knowledge to date on electron-excited molecule interactions clearly shows that the cross sections for certain electron-molecule collision processes can be very different from those involving ground state molecules. For example, optically enhanced electron attachment studies have shown that electron attachment to electronically excited molecules can occur with cross sections 10 6 to 10 7 times larger compared to ground state molecules. The study of electron-excited molecule interactions offers many experimental and theoretical challenges and opportunities and is both of fundamental and technological significance. 54 refs., 15 figs

Acenes, Heteroacenes and Analogous Molecules for Organic Photovoltaic and Field Effect Transistor Applications

Science.gov (United States)

Granger, Devin Benjamin

donor molecules for bulk heterojunction organic photovoltaics based on anthrathiophene and benzo[1,2-b:4,5-b']dithiophene central units like literature molecules containing fluorene and dithieno[2,3-b:2',3'-d]silole cores. The synthetic strategies of developing reduced symmetry benzo[1,2-b:4,5-b']dithiophene to study the effect of substitution around the central unit is also described. The optical and electronic properties of the donors and acceptors are described along with the performance and characteristics of devices employing these molecules. The final two data chapters focus on new nitrogen containing polycyclic hydrocarbons containing indolizine and (2.2.2) cyclazine units. The optical, electronic and other physical properties of these molecules are explored, in addition to the synthetic strategies for incorporating the indolizine and cyclazine units. By use of alkylsilylethynyl groups, crystal engineering was investigated for the benzo[2,3-b:5,6-b']diindolizine chromophore described in chapter 4 to target the 2-D "brick-work" packing motif for application in field effect transistor devices. Optical and electronic properties of the cyclazine end-capped acene molecules described in chapter 5 were investigated and described in relation to the base acene molecules. In both cases, density functional theory calculations were conducted to better understand unexpected optical properties of these molecules, which are like the linear acene series despite the non-linear attachment.

Superradiance Effects in the Linear and Nonlinear Optical Response of Quantum Dot Molecules

Science.gov (United States)

Sitek, A.; Machnikowski, P.

2008-11-01

We calculate the linear optical response from a single quantum dot molecule and the nonlinear, four-wave-mixing response from an inhomogeneously broadened ensemble of such molecules. We show that both optical signals are affected by the coupling-dependent superradiance effect and by optical interference between the two polarizations. As a result, the linear and nonlinear responses are not identical.

Improvement in rheumatic fever and rheumatic heart disease management and prevention using a health centre-based continuous quality improvement approach.

Science.gov (United States)

Ralph, Anna P; Fittock, Marea; Schultz, Rosalie; Thompson, Dale; Dowden, Michelle; Clemens, Tom; Parnaby, Matthew G; Clark, Michele; McDonald, Malcolm I; Edwards, Keith N; Carapetis, Jonathan R; Bailie, Ross S

2013-12-18

Rheumatic heart disease (RHD) remains a major health concern for Aboriginal Australians. A key component of RHD control is prevention of recurrent acute rheumatic fever (ARF) using long-term secondary prophylaxis with intramuscular benzathine penicillin (BPG). This is the most important and cost-effective step in RHD control. However, there are significant challenges to effective implementation of secondary prophylaxis programs. This project aimed to increase understanding and improve quality of RHD care through development and implementation of a continuous quality improvement (CQI) strategy. We used a CQI strategy to promote implementation of national best-practice ARF/RHD management guidelines at primary health care level in Indigenous communities of the Northern Territory (NT), Australia, 2008-2010. Participatory action research methods were employed to identify system barriers to delivery of high quality care. This entailed facilitated discussion with primary care staff aided by a system assessment tool (SAT). Participants were encouraged to develop and implement strategies to overcome identified barriers, including better record-keeping, triage systems and strategies for patient follow-up. To assess performance, clinical records were audited at baseline, then annually for two years. Key performance indicators included proportion of people receiving adequate secondary prophylaxis (≥80% of scheduled 4-weekly penicillin injections) and quality of documentation. Six health centres participated, servicing approximately 154 people with ARF/RHD. Improvements occurred in indicators of service delivery including proportion of people receiving ≥40% of their scheduled BPG (increasing from 81/116 [70%] at baseline to 84/103 [82%] in year three, p = 0.04), proportion of people reviewed by a doctor within the past two years (112/154 [73%] and 134/156 [86%], p = 0.003), and proportion of people who received influenza vaccination (57/154 [37%] to 86/156 [55%], p�

Charge Transfer Effect on Raman and Surface Enhanced Raman Spectroscopy of Furfural Molecules.

Science.gov (United States)

Wan, Fu; Shi, Haiyang; Chen, Weigen; Gu, Zhaoliang; Du, Lingling; Wang, Pinyi; Wang, Jianxin; Huang, Yingzhou

2017-08-02

The detection of furfural in transformer oil through surface enhanced Raman spectroscopy (SERS) is one of the most promising online monitoring techniques in the process of transformer aging. In this work, the Raman of individual furfural molecules and SERS of furfural-M x (M = Ag, Au, Cu) complexes are investigated through density functional theory (DFT). In the Raman spectrum of individual furfural molecules, the vibration mode of each Raman peak is figured out, and the deviation from experimental data is analyzed by surface charge distribution. In the SERS of furfural-M x complexes, the influence of atom number and species on SERS chemical enhancement factors (EFs) are studied, and are further analyzed by charge transfer effect. Our studies strengthen the understanding of charge transfer effect in the SERS of furfural molecules, which is important in the online monitoring of the transformer aging process through SERS.

In vitro investigation of the effect of matrix molecules on the behavior of colon cancer cells under the effect of geldanamycin derivative.

Science.gov (United States)

Vural, Kamil; Kosova, Funda; Kurt, Feyzan Özdal; Tuğlu, İbrahim

2017-10-01

The chaperone-binding drug, 17-allylamino-17-demethoxygeldanamycin, has recently come into clinical use. It is a derivative of geldanamycin, an ansamycin benzoquinone antibiotic with anti-carcinogenic effect. Understanding the effect of this drug on the cancer cells and their niche is important for treatment. We applied 17-allylamino-17-demethoxygeldanamycin to colon cancer cell line (Colo 205) on matrix molecules to investigate the relationship of apoptosis with terminal deoxynucleotidyl transferase dUTP nick end labeling immunocytochemistry and related gene expression. We used laminin and collagen I for matrix molecules and vascular endothelial growth factor for angiogenic structure. We also examined apoptosis-related signaling pathway including mitochondrial proteins, cytochrome c, Bcl-2, caspase-9, Apaf-1 expression using real-time polymerase chain reaction. There was clear effect of 17-allylamino-17-demethoxygeldanamycin that killed more cells on tissue culture plastic compared to matrix molecules. The IC 50 value was 0.58 µg/mL for tissue culture plastic compared with 0.64 µg/mL for laminin and 0.75 µg/mL for collagen I. The analyses showed that more cells on matrix molecules underwent apoptosis compared to that on tissue culture plastic. Apoptosis-related gene expression was similar in which Bcl-2 expression decreased and proapoptotic gene expression of the cells on matrix molecules increased compared to that on tissue culture plastic. However, the application of 17-allylamino-17-demethoxygeldanamycin was more effective for the cells on collagen I compared to the cells on laminin. There was also a decrease in angiogenesis as shown by the vascular endothelial growth factor staining. This was more pronounced by coating of the tissue culture plastic with matrix molecules. Our results supported the anti-cancer effect of 17-allylamino-17-demethoxygeldanamycin, and this effect depended on matrix molecules. This effect occurs through apoptosis, and related

Radiation effects on the laser ablative shockwaves from aluminum under atmospheric conditions

International Nuclear Information System (INIS)

Sai Shiva, S.; Leela, C.H.; Prem Kiran, P.; Sijoy, C.D.; Chaturvedi, Shashank

2015-01-01

The evolution of laser ablative shockwaves (LASW) from Aluminum under atmospheric pressures is numerically modeled using a one-dimensional, three-temperature (electron, ion and thermal radiation temperatures), non-equilibrium, radiation hydrodynamic (RHD) model. The governing RHD equations in Lagrangian form are solved by using an implicit scheme. Similarly, the energy relaxation between the electrons and ions and the electrons and thermal radiation are determined implicitly. Apart from these, the energy equation takes into account the flux-limited electron thermal heat flux. The RHD equations are closed by using a two temperature QEOS model for the Al. The MULTI-fs code is modified to incorporate the nanosecond laser absorption model via the photoionization (PI) and the inverse bremsstrahlung (IB) processes. The spatio-temporal evolution of the laser ablative shockwaves generated by focusing a second harmonic (532 nm, 7ns) of Nd:YAG laser on to Aluminum target under atmospheric pressures in air is captured using a shadowgraphy technique. These measurements are made from 200 ns to 10 μs after the laser pulse with a temporal resolution of 1.5 ns. We report the details of the RHD model and compare the simulated and experimental results for input laser energies in the range of 25 - 175 mJ per pulse. The evolution of the plasma parameters like electron density, charge states and the shockwaves launched into the ambient atmosphere due to expanding plasma plume are compared. The role of thermal radiation on the evolution of LASW from Al is discussed. (author)

Theoretical Investigations Regarding Single Molecules

DEFF Research Database (Denmark)

Pedersen, Kim Georg Lind

Neoclassical Valence Bond Theory, Quantum Transport, Quantum Interference, Kondo Effect, and Electron Pumping. Trap a single organic molecule between two electrodes and apply a bias voltage across this "molecular junction". When electrons pass through the molecule, the different electron paths can...... interfere destructively or constructively. Destructive interference effects in electron transport could potentially improve thermo-electrics, organic logic circuits and energy harvesting. We have investigated destructive interference in off-resonant transport through organic molecules, and have found a set...

Low dose radiation induced protein and its effect on expression of CD25 molecule in lymphocytes

International Nuclear Information System (INIS)

Lu Duicai; Su Liaoyuan

2001-01-01

Objective: To find the substantial basis for effects of low dose radiation, on development, extraction, and the biogical activity of the low-dose radiation-induced proteins, and the effects of LDR induced proteins on CD25 molecule expression of human lymphocytes. Methods: 1. Healthy Kumning male mice exposed to radiation of 226 Ra γ-rays at 5, 10 and 15 cGy respectively. The mice were killed 2 hours after exposure, the spleen cells were broken with ultrasonic energy and then ultra-centrifugalized at low temperature (4 degree C). The LDR-induced proteins were obtained in the supernatant solution. Then the changes of CD25 molecule was measured by flow cytometry (FCM) with immunofluorescence technique, which was used to reflect the effect of LDR induced proteins on CD25 molecule expression of human lymphocytes. Results: LDR induced proteins were obtained from spleen cells in mice exposed to 5-15 cGy whole body radiation. Conclusion: The expression of CD25 molecule of lymphocytes was increased significantly after use of LDR induced proteins. LDR induced proteins can enhance expression of CD25 molecule of lymphocytes slightly

Spin thermoelectric effects in organic single-molecule devices

Energy Technology Data Exchange (ETDEWEB)

Wang, H.L.; Wang, M.X.; Qian, C.; Hong, X.K.; Zhang, D.B.; Liu, Y.S.; Yang, X.F., E-mail: xfyang@cslg.edu.cn

2017-05-25

Highlights: • A stronger spin thermoelectric performance in a polyacetylene device is observed. • For the antiferromagnetic (AFM) ordering, a transport gap is opened. Thus the thermoelectric effects are largely enhanced. - Abstract: The spin thermoelectric performance of a polyacetylene chain bridging two zigzag graphene nanoribbons (ZGNRs) is investigated based on first principles method. Two different edge spin arrangements in ZGNRs are considered. For ferromagnetic (FM) ordering, transmission eigenstates with different spin indices distributed below and above Fermi level are observed, leading directly to a strong spin thermoelectric effect in a wide temperature range. With the edge spins arranged in the antiferromagnetic (AFM) ordering, an obvious transport gap appears in the system, which greatly enhances the thermoelectric effects. The presence of a small spin splitting also induces a spin thermoelectric effect greater than the charge thermoelectric effect in certain temperature range. In general, the single-molecule junction exhibits the potential to be used for the design of perfect thermospin devices.

Correlation and symmetry effects in transport through an artificial molecule

Energy Technology Data Exchange (ETDEWEB)

Ramirez, F. [Posgrado en Fisica de Materiales, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, Ensenada, Baja California (Mexico); Cota, E. [Centro de Ciencias de la Materia Condensada-UNAM, Ensenada, Baja California (Mexico); Ulloa, S.E. [Department of Physics and Astronomy and Condensed Matter and Surface Sciences Program, Ohio University, Athens, Ohio 45701-2979 (United States)

1999-02-01

Spectral weights and current-voltage characteristics of an artificial diatomic molecule are calculated, considering cases where the dots connected in series are in general different. The spectral weights allow us to understand the effects of correlations, their connection with selection rules for transport, and the role of excited states in the experimental conductance spectra of these coupled double dot systems (DDS). An extended Hubbard Hamiltonian with varying interdot tunneling strength is used as a model, incorporating quantum confinement in the DDS, interdot tunneling as well as intra- and interdot Coulomb interactions. We find that interdot tunneling values determine to a great extent the resulting eigenstates and corresponding spectral weights. Details of the state correlations strongly suppress most of the possible conduction channels, giving rise to effective selection rules for conductance through the molecule. Most states are found to make insignificant contributions to the total current for finite biases. We find also that the symmetry of the structure is reflected in the I-V characteristics, and is in qualitative agreement with experiment. {copyright} {ital 1999} {ital The American Physical Society}

Rheumatic heart disease: infectious disease origin, chronic care approach.

Science.gov (United States)

Katzenellenbogen, Judith M; Ralph, Anna P; Wyber, Rosemary; Carapetis, Jonathan R

2017-11-29

Rheumatic heart disease (RHD) is a chronic cardiac condition with an infectious aetiology, causing high disease burden in low-income settings. Affected individuals are young and associated morbidity is high. However, RHD is relatively neglected due to the populations involved and its lower incidence relative to other heart diseases. In this narrative review, we describe how RHD care can be informed by and integrated with models of care developed for priority non-communicable diseases (coronary heart disease), and high-burden communicable diseases (tuberculosis). Examining the four-level prevention model (primordial through tertiary prevention) suggests primordial and primary prevention of RHD can leverage off existing tuberculosis control efforts, given shared risk factors. Successes in coronary heart disease control provide inspiration for similarly bold initiatives for RHD. Further, we illustrate how the Chronic Care Model (CCM), developed for use in non-communicable diseases, offers a relevant framework to approach RHD care. Systems strengthening through greater integration of services can improve RHD programs. Strengthening of systems through integration/linkages with other well-performing and resourced services in conjunction with policies to adopt the CCM framework for the secondary and tertiary prevention of RHD in settings with limited resources, has the potential to significantly reduce the burden of RHD globally. More research is required to provide evidence-based recommendations for policy and service design.

Organic Semiconductor-Containing Supramolecules: Effect of Small Molecule Crystallization and Molecular Packing

KAUST Repository

Rancatore, Benjamin J.

2016-01-21

© 2016 American Chemical Society. Small molecules (SMs) with unique optical or electronic properties provide an opportunity to incorporate functionality into block copolymer (BCP)-based supramolecules. However, the assembly of supramolecules based on these highly crystalline molecules differs from their less crystalline counterparts. Here, two families of organic semiconductor SMs are investigated, where the composition of the crystalline core, the location (side- vs end-functionalization) of the alkyl solubilizing groups, and the constitution (branched vs linear) of the alkyl groups are varied. With these SMs, we present a systematic study of how the phase behavior of the SMs affects the overall assembly of these organic semiconductor-based supramolecules. The incorporation of SMs has a large effect on the interfacial curvature, the supramolecular periodicity, and the overall supramolecular morphology. The crystal packing of the SM within the supramolecule does not necessarily lead to the assembly of the comb block within the BCP microdomains, as is normally observed for alkyl-containing supramolecules. An unusual lamellar morphology with a wavy interface between the microdomains is observed due to changes in the packing structure of the small molecule within BCP microdomains. Since the supramolecular approach is modular and small molecules can be readily switched out, present studies provide useful guidance toward access supramolecular assemblies over several length scales using optically active and semiconducting small molecules.

Effect of an improved molecular potential on strong-field tunneling ionization of molecules

International Nuclear Information System (INIS)

Zhao Songfeng; Jin Cheng; Le, Anh-Thu; Lin, C. D.

2010-01-01

We study the effect of one-electron model potentials on the tunneling ionization rates of molecules in strong fields. By including electron correlation using the modified Leeuwen-Baerends (LB α) model, the binding energies of outer shells of molecules are significantly improved. However, we show that the tunneling ionization rates from the LB α do not differ much from the earlier calculations [Phys. Rev. A 81, 033423 (2010)], in which the local correlation potential was neglected.

Effects of Perchlorate on Organic Molecules under Simulated Mars Conditions

Science.gov (United States)

Carrier, B. L.; Kounaves, S. P.

2014-12-01

Perchlorate (ClO4-) was discovered in the northern polar region of Mars by the Mars Phoenix Lander in 2008 and has also been recently detected by the Curiosity Rover in Gale Crater [1,2]. Perchlorate has also been shown to be formed under current Mars conditions via the oxidation of mineral chlorides, further supporting the theory that perchlorate is present globally on Mars [3]. The discovery of perchlorate on Mars has raised important questions about the effects of perchlorate on the survival and detection of organic molecules. Although it has been shown that pyrolysis in the presence of perchlorate results in the alteration or destruction of organic molecules [4], few studies have been conducted on the potential effects of perchlorate on organic molecules under martian surface conditions. Although perchlorate is typically inert under Mars-typical temperatures [5], perchlorate does absorb high energy UV radiation, and has been shown to decompose to form reactive oxychlorine species such as chlorite (ClO2-) when exposed to martian conditions including UV or ionizing radiation [6,7]. Here we investigate the effects of perchlorate on the organic molecules tryptophan, benzoic acid and mellitic acid in order to determine how perchlorate may alter these compounds under Mars conditions. Experiments are performed in a Mars Simulation Chamber (MSC) capable of reproducing the temperature, pressure, atmospheric composition and UV flux found on Mars. Soil simulants are prepared consisting of SiO2 and each organic, as well as varying concentrations of perchlorate salts, and exposed in the MSC. Subsequent to exposure in the MSC samples are leached and the leachate analyzed by HPLC and LC-MS to determine the degree of degradation of the original organic and the identity of any potential decomposition products formed by oxidation or chlorination. References: [1] Kounaves et al., J. Geophys. Res. Planets, Vol. 115, p. E00E10, 2010 [2] Glavin et al., J. Geophys. Res. Planets, Vol

Awareness and distribution of ABO, Rhesus blood groups and haemoglobin phenotypes among medical undergraduates in a Nigerian university.

Science.gov (United States)

Akingbola, T S; Yuguda, S; Akinyemi, O O; Olomu, S

2016-09-01

In the past two decades the Nigerian government and religious organisations have put more emphasis on knowing the haemoglobin electrophoresis of school children and intending couples respectively. Knowledge of the distribution of blood groups and haemoglobin electrophoretic patterns among young people is vital for the prevention of haemoglobinopathies in the population and for providing effective blood banking services. Therefore, this study was designed to assess the frequency and awareness of blood group and haemoglobinphenotypes among a new set of fourth year clinical medical and dental students of the University of Ibadan, Nigeria. Data, including socio-demographics, self- reported blood group and haemoglobin phenotypes, were obtained from 155 students using a self-administered questionnaire. The ABO, Rhesus (Rh) blood groups and haemoglobin electrophoresis were determined by the tile (slide) technique and cellulose acetate at alkaline phrespectively. Only 43.9% of the participants knew their blood groups while less than a third (29.7%) knew their haemoglobin phenotypes. knowledge of both their blood groups and haemoglobin phenotypes was documented in as low as 20.6% of the respondents. The frequency of haemoglobin AA, AS, AC and. CC were 78.0%, 16.8%, 3.9% and 1.3% respectively. Similarly, the distribution of blood groups were: 0 RhD positive - 47.8%;0 RhD negative- 1.9%;ARhD positive- 21.9%; A RhD negative - 1.3%; B RhD positive - 23.2%; B RhD negative -1.3% and AB RhD positive - 2.6%. No participant was AB RhD negative. Participants who bad previously donated blood and those who were females were more likely to know their blood groups and haemoglobin phenotypes respectively (pblood groups and haemoglobin phenotypes among the medical and dental students was poor. Documentation and routine screening for haemoglobinphenotypes as well as blood grouping, accompanied by appropriate counseling should be institutionalised in Nigeriantertiary institutions.

Counteracting chemical chaperone effects on the single-molecule α-synuclein structural landscape.

Science.gov (United States)

Ferreon, Allan Chris M; Moosa, Mahdi Muhammad; Gambin, Yann; Deniz, Ashok A

2012-10-30

Protein structure and function depend on a close interplay between intrinsic folding energy landscapes and the chemistry of the protein environment. Osmolytes are small-molecule compounds that can act as chemical chaperones by altering the environment in a cellular context. Despite their importance, detailed studies on the role of these chemical chaperones in modulating structure and dimensions of intrinsically disordered proteins have been limited. Here, we used single-molecule Förster resonance energy transfer to test the counteraction hypothesis of counterbalancing effects between the protecting osmolyte trimethylamine-N-oxide (TMAO) and denaturing osmolyte urea for the case of α-synuclein, a Parkinson's disease-linked protein whose monomer exhibits significant disorder. The single-molecule experiments, which avoid complications from protein aggregation, do not exhibit clear solvent-induced cooperative protein transitions for these osmolytes, unlike results from previous studies on globular proteins. Our data demonstrate the ability of TMAO and urea to shift α-synuclein structures towards either more compact or expanded average dimensions. Strikingly, the experiments directly reveal that a 21 [urea][TMAO] ratio has a net neutral effect on the protein's dimensions, a result that holds regardless of the absolute osmolyte concentrations. Our findings shed light on a surprisingly simple aspect of the interplay between urea and TMAO on α-synuclein in the context of intrinsically disordered proteins, with potential implications for the biological roles of such chemical chaperones. The results also highlight the strengths of single-molecule experiments in directly probing the chemical physics of protein structure and disorder in more chemically complex environments.

Counteracting chemical chaperone effects on the single-molecule α-synuclein structural landscape

Science.gov (United States)

Ferreon, Allan Chris M.; Moosa, Mahdi Muhammad; Deniz, Ashok A.

2012-01-01

Protein structure and function depend on a close interplay between intrinsic folding energy landscapes and the chemistry of the protein environment. Osmolytes are small-molecule compounds that can act as chemical chaperones by altering the environment in a cellular context. Despite their importance, detailed studies on the role of these chemical chaperones in modulating structure and dimensions of intrinsically disordered proteins have been limited. Here, we used single-molecule Förster resonance energy transfer to test the counteraction hypothesis of counterbalancing effects between the protecting osmolyte trimethylamine-N-oxide (TMAO) and denaturing osmolyte urea for the case of α-synuclein, a Parkinson’s disease-linked protein whose monomer exhibits significant disorder. The single-molecule experiments, which avoid complications from protein aggregation, do not exhibit clear solvent-induced cooperative protein transitions for these osmolytes, unlike results from previous studies on globular proteins. Our data demonstrate the ability of TMAO and urea to shift α-synuclein structures towards either more compact or expanded average dimensions. Strikingly, the experiments directly reveal that a 2∶1 [urea]∶[TMAO] ratio has a net neutral effect on the protein’s dimensions, a result that holds regardless of the absolute osmolyte concentrations. Our findings shed light on a surprisingly simple aspect of the interplay between urea and TMAO on α-synuclein in the context of intrinsically disordered proteins, with potential implications for the biological roles of such chemical chaperones. The results also highlight the strengths of single-molecule experiments in directly probing the chemical physics of protein structure and disorder in more chemically complex environments. PMID:22826265

[The Hospital Information System of the Brazilian National Unified Health System: a preliminary evaluation of performance in monitoring RhD hemolytic disease of the newborn].

Science.gov (United States)

Lobato, Gustavo; Reichenheim, Michael Eduardo; Coeli, Claudia Medina

2008-03-01

This study aimed to evaluate the adequacy of the Hospital Information System of the National Unified Health System (SIH-SUS) in identifying cases of RhD hemolytic disease of the newborn (HDN) at the Fernandes Figueira Institute (IFF/FIOCRUZ) from 1998 to 2003. Neonatal records, data from the Medical Archives, and AIH (Hospital Admissions Authorization Form) data consolidated in the SIH-SUS were analyzed. Cases were identified according to the following fields: principal diagnosis, secondary diagnosis, and procedure performed. During the period studied, 194 cases of HDN were diagnosed. The Medical Archives registered 148 newborns with HDN, however only 147 AIHs were issued and 145 consolidated in the SIH-SUS. Among these 145 cases, 84 cited HDN as the principal diagnosis, while secondary diagnosis identified 38 additional cases and the procedures performed failed to identify any further cases. Thus, the SIH-SUS identified only 122 (62.9%) of the 194 cases of HDN treated at the IFF/FIOCRUZ. Although it is necessary to evaluate other units, the SIH-SUS does not appear to be reliable for monitoring HDN. Additional studies are essential for employing secondary administrative data in the context of epidemiological surveillance.

Clinical outcomes for young people with screening-detected and clinically-diagnosed rheumatic heart disease in Fiji.

Science.gov (United States)

Engelman, Daniel; Mataika, Reapi L; Ah Kee, Maureen; Donath, Susan; Parks, Tom; Colquhoun, Samantha M; Carapetis, Jonathan R; Kado, Joseph H; Steer, Andrew C

2017-08-01

Echocardiographic screening is under consideration as a disease control strategy for rheumatic heart disease (RHD). However, clinical outcomes of young people with screening-detected RHD are unknown. We aimed to describe the outcomes for a cohort with screening-detected RHD, in comparison to patients with clinically-diagnosed RHD. A retrospective cohort study included all young people with screening-detected RHD in the Central Division of Fiji in the primary cohort. Screen-negative and clinically-diagnosed comparison groups were matched 1:1 to the primary cohort. Data were collected on mortality, clinical complications and healthcare utilisation from the electronic and paper health records and existing databases. Seventy participants were included in each group. Demographic characteristics of the groups were similar (median age 11years, 69% female, median follow-up 7years). There were nine (12.9%) RHD-related deaths in the clinically-diagnosed group and one (1.4%) in the screening-detected group (Incident Rate Ratio: 9.6, 95% CI 1.3-420.6). Complications of RHD were observed in 39 (55.7%) clinically-diagnosed cases, four (20%) screening-detected cases and one (1.4%) screen-negative case. There were significant differences in the cumulative complication curves of the groups (pFiji. The prognosis of clinically-diagnosed RHD remains poor, with very high mortality and complication rates. Further studies in other settings will inform RHD screening policy. Comprehensive control strategies are required for disease prevention. Copyright © 2017 Elsevier B.V. All rights reserved.

Prevalence of rheumatic valvular heart disease in Rwandan school children: echocardiographic evaluation using the World Heart Federation criteria

Science.gov (United States)

Mucumbitsi, J; Bulwer, B; Mutesa, L; Ndahindwa, MD, MSc; Semakula, M; Rusingiza, E; Arya, P; Breakey, S; Patton-Bolman, C; Kaplan, E L

2017-01-01

Summary Background: Rheumatic fever (RF) and rheumatic valvular heart disease (RHD) remain important medical, surgical and public health concerns in many parts of the world, especially in sub-Saharan Africa. However, there are no published data from Rwanda. We performed a RHD prevalence study in a randomly selected sample of Rwandan school children using the 2012 World Heart Federation (WHF) criteria. Methods: Echocardiographic assessment of 2 501 Rwandan school children from 10 schools in the Gasabo district near Kigali was carried out. Resulting data were evaluated by four experienced echocardiographers. Statistical analyses were carried out by statisticians. Results: RHD prevalence was 6.8/1 000 children examined (95% CI: 4.2/1 000–10.9/1 000). Seventeen met WHF criteria for RHD, 13 fulfilled criteria for ‘borderline’ RHD and four were ‘definite’ RHD. None of these 17 had been previously identified. Conclusion: These data indicate a significant burden of RHD in Rwanda and support a need for defined public health RF control programmes in children there. PMID:28252675

Gene Frequency and Heritability of Rh Blood Group Gene in 44 Human Populations

Directory of Open Access Journals (Sweden)

Supriyo CHAKRABORTY

2010-09-01

Full Text Available The frequency of RhD and Rhd alleles of Rh blood group gene was estimated in 44 human populations distributed all over the world from the RhD phenotypic data. The average frequency of RhD and Rhd allele over these populations was 0.70 and 0.30, respectively. Higher frequency of RhD allele than the expected estimate (0.50 in all the populations, under Hardy-Weinberg equilibrium condition assuming equal frequency of both alleles in the initial population, indicated inbreeding at RhD/d locus as well as natural selection for RhD allele. Very high heritability estimate (84.04% of Rh allele frequency revealed that this trait was under weak selection pressure and resulted in greater genetic variation in existing populations. It is consistent with Fishers fundamental theorem of natural selection. The results from the present study suggest that inbreeding at RhD/d locus and some other factors (possibly mutation, migration and genetic drift other than natural selection alone played major roles in changing the Rh allele frequency in these populations.

Fano effect in the transport of an artificial molecule

Science.gov (United States)

Norimoto, Shota; Nakamura, Shuji; Okazaki, Yuma; Arakawa, Tomonori; Asano, Kenichi; Onomitsu, Koji; Kobayashi, Kensuke; Kaneko, Nobu-hisa

2018-05-01

The Fano effect is a ubiquitous phenomenon arising from interference between a discrete energy state and an energy continuum. We explore this effect in an artificial molecule, namely, two lateral quantum dots (QDs) fabricated from a two-dimensional electron gas system and coupled in series. When the coupling between the leads and QDs is small, the charge stability diagram of the system shows a honeycomb lattice structure that is characteristic of a double QD system. As the coupling increases, a honeycomb structure consisting of the Fano resonances emerges. A numerical simulation based on the T-matrix method can satisfactorily reproduce our experimental observation. This report constitutes a clear example of the ubiquitous nature of the Fano effect in mesoscopic transport.

New strategies to prevent fetal and neonatal complications in Rhesus D immunization

OpenAIRE

Tiblad, Eleonor

2012-01-01

The general purpose of this thesis was to investigate if fetal and neonatal complications due to RhD immunization in the mother could be prevented by 1) reducing procedurerelated complications in intrauterine blood transfusions and by 2) reducing the incidence of RhD immunization by providing routine antenatal anti-D prophylaxis during pregnancy selectively to non-immunized RhD negative women with RhD positive fetuses. Paper I was a retrospective study including 284 intra...

Angle-resolved effective potentials for disk-shaped molecules

Energy Technology Data Exchange (ETDEWEB)

Heinemann, Thomas, E-mail: thomas.heinemann@tu-berlin.de; Klapp, Sabine H. L., E-mail: klapp@physik.tu-berlin.de [Institut für Theoretische Physik, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin (Germany); Palczynski, Karol, E-mail: karol.palczynski@helmholtz-berlin.de; Dzubiella, Joachim, E-mail: joachim.dzubiella@helmholtz-berlin.de [Institut für Physik, Humboldt Universität zu Berlin, Newtonstraße 15, 12489 Berlin (Germany); Helmholtz Zentrum Berlin (HZB), Institute of Soft Matter and Functional Materials, Hahn-Meitner Platz 1, 14109 Berlin (Germany)

2014-12-07

We present an approach for calculating coarse-grained angle-resolved effective pair potentials for uniaxial molecules. For integrating out the intramolecular degrees of freedom we apply umbrella sampling and steered dynamics techniques in atomistically-resolved molecular dynamics (MD) computer simulations. Throughout this study we focus on disk-like molecules such as coronene. To develop the methods we focus on integrating out the van der Waals and intramolecular interactions, while electrostatic charge contributions are neglected. The resulting coarse-grained pair potential reveals a strong temperature and angle dependence. In the next step we fit the numerical data with various Gay-Berne-like potentials to be used in more efficient simulations on larger scales. The quality of the resulting coarse-grained results is evaluated by comparing their pair and many-body structure as well as some thermodynamic quantities self-consistently to the outcome of atomistic MD simulations of many-particle systems. We find that angle-resolved potentials are essential not only to accurately describe crystal structures but also for fluid systems where simple isotropic potentials start to fail already for low to moderate packing fractions. Further, in describing these states it is crucial to take into account the pronounced temperature dependence arising in selected pair configurations due to bending fluctuations.

Effect of continuous recombinant human endostatin pumping combined with TP chemotherapy on serum malignant molecules and angiogenesis molecules in patients with advanced ovarian cancer

Directory of Open Access Journals (Sweden)

Wei-Dong Chen

2017-05-01

Full Text Available Objective: To study the effect of continuous recombinant human endostatin pumping combined with TP chemotherapy on serum malignant molecules and angiogenesis molecules in patients with advanced ovarian cancer. Methods: 78 patients with advanced ovarian cancer who were treated in our hospital between July 2011 and December 2015 were selected and divided into observation group and control group (n=39 according to the single-blind randomized control method. Before treatment and after 4 cycles of treatment, electrochemical luminescence immunity analyzer was used to detect serum tumor marker levels; RIA method was used to determine serum apoptosis molecule levels; enzyme-linked immunosorbent assay (ELISA was used to detect the serum angiogenesis molecule levels. Results: Before treatment, differences in serum levels of tumor markers, apoptosis molecules and angiogenesis molecules were not statistically significant between two groups of patients (P>0.05. After 4 cycles of treatment, serum carbohydrate antigen 125 (CA125, carbohydrate antigen 153 (CA153, human epididymis protein 4 (HE4, carcinoembryonic antigen (CEA, human chorionic gonadotropin (β-HCG, Bcl-2, Survivin, Bag-1, angiogenin-2 (Ang-2, vascular endothelial growth factor (VEGF and basic fibroblast growth factor (bFGF levels of observation group were significantly lower than those of control group (P<0.05 while Bax level was significantly higher than that of control group (P<0.05. Conclusions: Continuous recombinant human endostatin pumping combined with TP chemotherapy can decrease the malignant degree of advanced ovarian cancer and inhibit angiogenesis.

Molecule Matters van der Waals Molecules

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 14; Issue 12. Molecule Matters van der Waals Molecules - Noble Gas Clusters are London Molecules! E Arunan. Feature Article Volume 14 Issue 12 December 2009 pp 1210-1222 ...

VizieR Online Data Catalog: STAGGER-grid of 3D stellar models. V. (Chiavassa+, 2018)

Science.gov (United States)

Chiavassa, A.; Casagrande, L.; Collet, R.; Magic, Z.; Bigot, L.; Thevenin, F.; Asplund, M.

2018-01-01

Table B0: RHD simulations' stellar parameters, bolometric magnitude, and bolometric correction for Johnson-Cousins, 2MASS, SDSS (columns 13 to 17), and Gaia systems Table 4: RHD simulations' stellar parameters, bolometric magnitude, and bolometric correction for SkyMapper photometric system, and Stroemgren index b-y, m1=(v-b)-(b-y), and c1=(u-v)-(v-b) Table 5: RHD simulations' stellar parameters, bolometric magnitude, and bolometric correction for the HST-WFC3 in VEGA system Table 6: RHD simulations' stellar parameters, bolometric magnitude, and bolometric correction for the HST-WFC3 in ST system Table 7: RHD simulations' stellar parameters, bolometric magnitude, and bolometric correction for the HST-WFC3 in AB system (5 data files).

Rheumatic Heart Disease in Kerala: A Vanishing Entity? An Echo Doppler Study in 5–15-Years-Old School Children

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Bigesh Nair

2015-01-01

Full Text Available Background. Early detection of subclinical rheumatic heart disease by use of echocardiography warrants timely implementation of secondary antibiotic prophylaxis and thereby prevents or retards its related complications. Objectives. The objective of this epidemiological study was to determine prevalence of RHD by echocardiography using World Heart Federation criteria in randomly selected school children of Trivandrum. Methods. This was a population-based cross-sectional screening study carried out in Trivandrum. A total of 2060 school children, 5–15 years, were randomly selected from five government and two private (aided schools. All enrolled children were screened for RHD according to standard clinical and WHF criteria of echocardiography. Results. Echocardiographic examinations confirmed RHD in 5 children out of 146 clinically suspected cases. Thus, clinical prevalence was found to be 2.4 per 1000. According to WHF criteria of echocardiography, 12 children (12/2060 were diagnosed with RHD corresponding to echocardiographic prevalence of 5.83 cases per 1000. As per criteria, 6 children were diagnosed with definite RHD and 6 with borderline RHD. Conclusions. The results of the current study demonstrate that echocardiography is more sensitive and feasible in detecting clinically silent RHD. Our study, the largest school survey of south India till date, points towards declining prevalence of RHD (5.83/1000 cases using WHF criteria in Kerala.

Coronal 2D MR cholangiography overestimates the length of the right hepatic duct in liver transplantation donors

International Nuclear Information System (INIS)

Kim, Bohyun; Kim, Kyoung Won; Kim, So Yeon; Park, So Hyun; Lee, Jeongjin; Song, Gi Won; Jung, Dong-Hwan; Ha, Tae-Yong; Lee, Sung Gyu

2017-01-01

To compare the length of the right hepatic duct (RHD) measured on rotatory coronal 2D MR cholangiography (MRC), rotatory axial 2D MRC, and reconstructed 3D MRC. Sixty-seven donors underwent coronal and axial 2D projection MRC and 3D MRC. RHD length was measured and categorized as ultrashort (≤1 mm), short (>1-14 mm), and long (>14 mm). The measured length, frequency of overestimation, and the degree of underestimation between two 2D MRC sets were compared to 3D MRC. The length of the RHD from 3D MRC, coronal 2D MRC, and axial 2D MRC showed significant difference (p < 0.05). RHD was frequently overestimated on the coronal than on axial 2D MRC (61.2 % vs. 9 %; p <.0001). On coronal 2D MRC, four (6 %) with short RHD and one (1.5 %) with ultrashort RHD were over-categorized as long RHD. On axial 2D MRC, overestimation was mostly <1 mm (83.3 %), none exceeding 3 mm or over-categorized. The degree of underestimation between the two projection planes was comparable. Coronal 2D MRC overestimates the RHD in liver donors. We suggest adding axial 2D MRC to conventional coronal 2D MRC in the preoperative workup protocol for living liver donors to avoid unexpected confrontation with multiple ductal openings when harvesting the graft. (orig.)

Coronal 2D MR cholangiography overestimates the length of the right hepatic duct in liver transplantation donors

Energy Technology Data Exchange (ETDEWEB)

Kim, Bohyun [University of Ulsan College of Medicine, Department of Radiology, Asan Medical Center, 88, Olympic-ro 43-gil, Songpa-gu, Seoul (Korea, Republic of); Ajou University School of Medicine, Department of Radiology, Ajou University Medical Center, Suwon (Korea, Republic of); Kim, Kyoung Won; Kim, So Yeon; Park, So Hyun [University of Ulsan College of Medicine, Department of Radiology, Asan Medical Center, 88, Olympic-ro 43-gil, Songpa-gu, Seoul (Korea, Republic of); Lee, Jeongjin [Soongsil University, School of Computer Science and Engineering, Seoul (Korea, Republic of); Song, Gi Won; Jung, Dong-Hwan; Ha, Tae-Yong; Lee, Sung Gyu [University of Ulsan College of Medicine, Department of Surgery, Division of Hepatobiliary and Liver Transplantation Surgery, Asan Medical Center, Seoul (Korea, Republic of)

2017-05-15

To compare the length of the right hepatic duct (RHD) measured on rotatory coronal 2D MR cholangiography (MRC), rotatory axial 2D MRC, and reconstructed 3D MRC. Sixty-seven donors underwent coronal and axial 2D projection MRC and 3D MRC. RHD length was measured and categorized as ultrashort (≤1 mm), short (>1-14 mm), and long (>14 mm). The measured length, frequency of overestimation, and the degree of underestimation between two 2D MRC sets were compared to 3D MRC. The length of the RHD from 3D MRC, coronal 2D MRC, and axial 2D MRC showed significant difference (p < 0.05). RHD was frequently overestimated on the coronal than on axial 2D MRC (61.2 % vs. 9 %; p <.0001). On coronal 2D MRC, four (6 %) with short RHD and one (1.5 %) with ultrashort RHD were over-categorized as long RHD. On axial 2D MRC, overestimation was mostly <1 mm (83.3 %), none exceeding 3 mm or over-categorized. The degree of underestimation between the two projection planes was comparable. Coronal 2D MRC overestimates the RHD in liver donors. We suggest adding axial 2D MRC to conventional coronal 2D MRC in the preoperative workup protocol for living liver donors to avoid unexpected confrontation with multiple ductal openings when harvesting the graft. (orig.)

Effect of the environment on the electrical conductance of the single benzene-1,4-diamine molecule junction

Directory of Open Access Journals (Sweden)

Shigeto Nakashima

2011-11-01

Full Text Available We investigated the effect of the environment on the electrical conductance of a single benzene-1,4-diamine (BDA molecule bridging Au electrodes, using the scanning tunneling microscope (STM. The conductance of the single BDA molecule junction decreased upon a change in the environment from tetraglyme, to mesitylene, to water, and finally to N2 gas, while the spread in the conductance value increased. The order of the conductance values of the single BDA molecule junction was explained by the strength of the interaction between the solvent molecules and the Au electrodes. The order of the spread in the conductance values was explained by the diversity in the coverage of the BDA molecule at metal electrodes and atomic and molecular motion of the single-molecule junction.

TeV scale resonant leptogenesis from supersymmetry breaking

International Nuclear Information System (INIS)

Hambye, Thomas; March-Russell, John; West, Stephen M.

2004-01-01

We propose a model of TeV-scale resonant leptogenesis based upon recent models of the generation of light neutrino masses from supersymmetry-breaking effects with TeV-scale right-handed (rhd) neutrinos, N i . The model leads to naturally large cosmological lepton asymmetries via the resonant behaviour of the one-loop self-energy contribution to N i decay. Our model addresses the primary problems of previous phenomenological studies of low-energy leptogenesis: a rational for TeV-scale rhd neutrinos with small Yukawa couplings so that the out-of equilibrium condition for N i decay is satisfied; the origin of the tiny, but non-zero mass splitting required between at least two N i masses; and the necessary non-trivial breaking of flavour symmetries in the rhd neutrino sector. The low mass-scale of the rhd neutrinos and their super partners, and the TeV-scale A-terms automatically contained within the model offer opportunities for partial direct experimental tests of this leptogenesis mechanism at future colliders. (author)

Single Molecule Effects of Osteogenesis Imperfecta Mutations in Tropocollagen Protein Domains

Science.gov (United States)

2008-12-02

Single molecule effects of osteogenesis imperfecta mutations in tropocollagen protein domains Alfonso Gautieri,1,2 Simone Vesentini,2 Alberto...2008 proteinscience.org Abstract: Osteogenesis imperfecta (OI) is a genetic disease characterized by fragile bones, skeletal deformities and, in severe...diagnosis and treatment, an effort referred to as materiomics. Keywords: steered molecular dynamics; osteogenesis imperfecta ; Young’s modulus; collagen

Role of Natural Autoantibodies in Ugandans With Rheumatic Heart Disease and HIV☆

Science.gov (United States)

Huck, Daniel M.; Okello, Emmy; Mirembe, Grace; Ssinabulya, Isaac; Zidar, David A.; Silverman, Gregg J.; Getu, Lelise; Nowacki, Amy S.; Calabrese, Leonard H.; Salata, Robert A.; Longenecker, Chris T.

2016-01-01

Background Rheumatic heart disease (RHD) and HIV are prevalent diseases in sub-Saharan Africa, but little is known about their potential interrelationships. The objective of this study was to assess the prevalence of protective natural autoantibodies among patients with RHD in Uganda, and to determine whether the levels of these autoantibodies are affected by HIV status. Methods Participants were grouped according to RHD and HIV status. The three control groups (RHD − HIV −, RHD − HIV +, RHD + HIV −) were age-matched to the RHD + HIV + participants. All participants underwent HIV testing and echocardiography to evaluate for RHD. Natural autoantibody levels reactive with phosphorylcholine (PC) and malondialdehyde (MDA) were measured. Findings We enrolled 220 participants; 21 with both RHD and HIV. Ages ranged from 10 to 60 years, with female predominance (144/220, 65%). After adjusting for age and gender, HIV infection and RHD were each associated with low IgM anti-PC (HIV: p disease. PMID:27077123

[The effect of spermine on acid-base equilibrium in DNA molecule].

Science.gov (United States)

Slonitskiĭ, S V; Kuptsov, V Iu

1990-01-01

The influence of spermine (Sp) on the acid-induced predenaturational and denaturational transitions in the DNA molecule structure has been studied by means of circular dichroism, spectrophotometric and viscometric titration at supporting electrolyte concentration 10 mM NaCl. The data available indicate that at [N]/[P] less than or equal to 0.60 (here [N] and [P] are molar concentrations of Sp nitrogen and DNA phosphours, respectively) the cooperative structural B----B(+)----S transitions are accompanied by the DNA double-helice winding. No competition for proton acceptor sites in the DNA molecule between H+ and Sp4+ cations has been observed when binding to neutral macromolecule. At 0.60 less than or equal to [N]/[P] less than or equal to 0.75 the displacement of the B----B(+)----S transitions midpoints to acidic pH region has been established. This is accompanied by DNA condensation and the appearance of differential scattering of circularly polarized light. The calculations carried out in the framework of the two-variable Manning theory have shown that the acid-induced reduction of the effective polyion charge density facilitates the Sp-induced DNA condensation. It has been shown that the acid-base equilibrium in the DNA molecule is determined by local [H+] in the 2-3 A hydrated monolayer of the macromolecule. An adequate estimation of [H+] can be obtained on the basis of the Poisson-Boltzman approach. The data obtained are consistent with recently proposed hypothesis of polyelectrolyte invariance of the acid-base equilibrium in the DNA molecule.

The "adjuvant effect" of the polymorphic B-G antigens of the chicken major histocompatibility complex analyzed using purified molecules incorporated in liposomes

DEFF Research Database (Denmark)

Salomonsen, J; Eriksson, H; Skjødt, K

1991-01-01

The polymorphic B-G region of the chicken major histocompatibility complex has previously been shown to mediate an "adjuvant effect" on the humoral response to other erythrocyte alloantigens. We demonstrate here that B-G molecules purified with monoclonal antibodies exert this adjuvant effect...... on the production of alloantibodies to chicken class I (B-F) molecules, when the two are in the same liposome. The adjuvant effect may in part be mediated by antibodies, since the antibody response to B-G molecules occurs much faster than the response to B-F molecules, and conditions in which antibodies to B......-G are present increase the speed of the response to B-F molecules. We also found that the presence of B-G molecules in separate liposomes results in a lack of response to B-F molecules. In the light of this and other data, we consider the possible roles for the polymorphic B-G molecules, particularly...

Molecule Matters van der Waals Molecules

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 7. Molecule Matters van der Waals Molecules - Rg•••HF Complexes are Debye Molecules! E Arunan. Feature Article Volume 15 Issue 7 July 2010 pp 667-674. Fulltext. Click here to view fulltext PDF. Permanent link:

Risk Factors of Rheumatic Heart Disease in Bangladesh: A Case-Control Study

Science.gov (United States)

Riaz, Baizid Khoorshid; Karim, Md. Nazmul; Chowdhury, Kamrun Nahar; Chowdhury, Shahabul Huda; Rahman, Md. Ridwanur

2013-01-01

Not all cases of rheumatic fever (RF) end up as rheumatic heart disease (RHD). The fact raises the possibility of existence of a subgroup with characteristics that prevent RF patients from developing the RHD. The present study aimed at exploring the risk factors among patients with RHD. The study assessed the risk of RHD among people both with and without RF. In total, 103 consecutive RHD patients were recruited as cases who reported to the National Centre for Control of Rheumatic Fever and Heart Disease, Dhaka, Bangladesh. Of 309 controls, 103 were RF patients selected from the same centre, and the remaining 206 controls were selected from Shaheed Suhrawardy Medical College Hospital, who got admitted for other non-cardiac ailments. RHD was confirmed by auscultation and colour Doppler echocardiography. RF was diagnosed based on the modified Jones criteria. An unadjusted odds ratio was generated for each variable, with 95% confidence interval (CI), and only significant factors were considered candidate for multivariate analysis. Three separate binary logistic regression models were generated to assess the risk factors of RF, risk factors of RHD compared to non-rheumatic control patients, and risk factors of RHD compared to control with RF. RF and RHD shared almost a similar set of risk factors in the population. In general, age over 19 years was found to be protective of RF; however, age of the majority (62.1%) of the RHD cases was over 19 years. Women [odds ratio (OR)=2.2, 95% CI 1.1-4.3], urban resident (OR=3.1, 95% CI 1.2–8.4), dwellers in brick-built house (OR=3.6, 95% CI 1.6-8.1), having >2 siblings (OR=3.1, 95% CI 1.5- 6.3), offspring of working mothers (OR=7.6, 95% CI 2.0-24.2), illiterate mother (OR=2.6, 95% CI 1.2-5.8), and those who did not brush after taking meals (OR=2.5, 95% CI 1.0-6.3) were more likely to develop RF. However, more than 5 members in a family showed a reduced risk of RF. RHD shared almost a similar set of factors in general. More than

Electron transport in liquids: effect of unbalancing the methane molecule by deuteration

International Nuclear Information System (INIS)

Floriano, M.A.; Freeman, G.R.

1983-01-01

The mobility of electrons in nonpolar liquids is strongly dependent on the molecular shape. In spherelike methane the mobility is three orders of magnitude greater than in the rodlike ethane. To investigate the enormous gap between methane and ethane, the effect of slightly perturbing the symmetry of the methane molecule by progressive deuterium substitution was studied. At temperatures near the triple point (T/Tsub(c) approximately 0.48) and near the mobility maximum (T/Tsub(c) approximately 0.93) the mobilities change in the order: CH 4 > CH 3 D > CH 2 D 2 3 approximately CD 4 . The differences are related to the symmetries of the molecules and to the rotational motions. (Authors)

Seven key actions to eradicate rheumatic heart disease in Africa: the Addis Ababa communiqué.

Science.gov (United States)

Watkins, David; Zuhlke, Liesl; Engel, Mark; Daniels, Rezeen; Francis, Veronica; Shaboodien, Gasnat; Kango, Mabvuto; Abul-Fadl, Azza; Adeoye, Abiodun; Ali, Sulafa; Al-Kebsi, Mohammed; Bode-Thomas, Fidelia; Bukhman, Gene; Damasceno, Albertino; Goshu, Dejuma Yadeta; Elghamrawy, Alaa; Gitura, Bernard; Haileamlak, Abraham; Hailu, Abraha; Hugo-Hamman, Christopher; Justus, Steve; Karthikeyan, Ganesan; Kennedy, Neil; Lwabi, Peter; Mamo, Yoseph; Mntla, Pindile; Sutton, Chris; Mocumbi, Ana Olga; Mondo, Charles; Mtaja, Agnes; Musuku, John; Mucumbitsi, Joseph; Murango, Louis; Nel, George; Ogendo, Stephen; Ogola, Elijah; Ojji, Dike; Olunuga, Taiwo Olabisi; Redi, Mekia Mohammed; Rusingiza, Kamanzi Emmanuel; Sani, Mahmoud; Sheta, Sahar; Shongwe, Steven; van Dam, Joris; Gamra, Habib; Carapetis, Jonathan; Lennon, Diana; Mayosi, Bongani M

Acute rheumatic fever (ARF) and rheumatic heart disease (RHD) remain major causes of heart failure, stroke and death among African women and children, despite being preventable and imminently treatable. From 21 to 22 February 2015, the Social Cluster of the Africa Union Commission (AUC) hosted a consultation with RHD experts convened by the Pan-African Society of Cardiology (PASCAR) in Addis Ababa, Ethiopia, to develop a 'roadmap' of key actions that need to be taken by governments to eliminate ARF and eradicate RHD in Africa. Seven priority areas for action were adopted: (1) create prospective disease registers at sentinel sites in affected countries to measure disease burden and track progress towards the reduction of mortality by 25% by the year 2025, (2) ensure an adequate supply of high-quality benzathine penicillin for the primary and secondary prevention of ARF/RHD, (3) improve access to reproductive health services for women with RHD and other non-communicable diseases (NCD), (4) decentralise technical expertise and technology for diagnosing and managing ARF and RHD (including ultrasound of the heart), (5) establish national and regional centres of excellence for essential cardiac surgery for the treatment of affected patients and training of cardiovascular practitioners of the future, (6) initiate national multi-sectoral RHD programmes within NCD control programmes of affected countries, and (7) foster international partnerships with multinational organisations for resource mobilisation, monitoring and evaluation of the programme to end RHD in Africa. This Addis Ababa communiqué has since been endorsed by African Union heads of state, and plans are underway to implement the roadmap in order to end ARF and RHD in Africa in our lifetime.

Quantifying small molecule phenotypic effects using mitochondrial morpho-functional fingerprinting and machine learning

Science.gov (United States)

Blanchet, Lionel; Smeitink, Jan A. M.; van Emst-de Vries, Sjenet E.; Vogels, Caroline; Pellegrini, Mina; Jonckheere, An I.; Rodenburg, Richard J. T.; Buydens, Lutgarde M. C.; Beyrath, Julien; Willems, Peter H. G. M.; Koopman, Werner J. H.

2015-01-01

In primary fibroblasts from Leigh Syndrome (LS) patients, isolated mitochondrial complex I deficiency is associated with increased reactive oxygen species levels and mitochondrial morpho-functional changes. Empirical evidence suggests these aberrations constitute linked therapeutic targets for small chemical molecules. However, the latter generally induce multiple subtle effects, meaning that in vitro potency analysis or single-parameter high-throughput cell screening are of limited use to identify these molecules. We combine automated image quantification and artificial intelligence to discriminate between primary fibroblasts of a healthy individual and a LS patient based upon their mitochondrial morpho-functional phenotype. We then evaluate the effects of newly developed Trolox variants in LS patient cells. This revealed that Trolox ornithylamide hydrochloride best counterbalanced mitochondrial morpho-functional aberrations, effectively scavenged ROS and increased the maximal activity of mitochondrial complexes I, IV and citrate synthase. Our results suggest that Trolox-derived antioxidants are promising candidates in therapy development for human mitochondrial disorders.

Polarization effects on the electric properties of urea and thiourea molecules in solid phase

International Nuclear Information System (INIS)

Santos, O. L.; Fonseca, T. L.; Sabino, J. R.; Georg, H. C.; Castro, M. A.

2015-01-01

We present theoretical results for the dipole moment, linear polarizability, and first hyperpolarizability of the urea and thiourea molecules in solid phase. The in-crystal electric properties were determined by applying a supermolecule approach in combination with an iterative electrostatic scheme, in which the surrounding molecules are represented by point charges. It is found for both urea and thiourea molecules that the influence of the polarization effects is mild for the linear polarizability, but it is marked for the dipole moment and first hyperpolarizability. The replacement of oxygen atoms by sulfur atoms increases, in general, the electric responses. Our second-order Møller–Plesset perturbation theory based iterative scheme predicts for the in-crystal dipole moment of urea and thiourea the values of 7.54 and 9.19 D which are, respectively, increased by 61% and 58%, in comparison with the corresponding isolated values. The result for urea is in agreement with the available experimental result of 6.56 D. In addition, we present an estimate of macroscopic quantities considering explicit unit cells of urea and thiourea crystals including environment polarization effects. These supermolecule calculations take into account partially the exchange and dispersion effects. The results illustrate the role played by the electrostatic interactions on the static second-order nonlinear susceptibility of the urea crystal

Changes in the expression of Th17 cell-associated cytokines in the development of rheumatic heart disease.

Science.gov (United States)

Wen, Yun; Zeng, Zhiyu; Gui, Chun; Li, Lang; Li, Wenting

2015-01-01

Autoimmunity plays a critical role in the development of rheumatic heart disease (RHD). Recent studies have linked Th17 cells to the autoimmune mechanism associated with RHD. This study aimed to investigate changes in Th17 cell-related cytokine expression in acute and chronic RHD. We established a Lewis rat model of experimental RHD, which was induced by inactivated Group A streptococci and complete Freund's adjuvant. After 7- and 24-week intervention treatments, we measured serum levels of interleukin-17 (IL-17) and IL-6, key cytokines associated with Th17 cells, using a Luminex liquichip method, and levels of IL-17 and IL-6 in heart tissues using immunohistochemical assays. Moreover, expression levels of IL-17, IL-21, IL-6, and IL-23 in mitral valve tissues of human RHD patients were also measured using immunohistochemistry. Compared with the normal control group, serum IL-17 and IL-6 concentrations were significantly increased, and the expression levels of IL-17 and IL-6 in the mitral valve were also significantly increased in 7- or 24-week RHD rats (P<.017). Compared with the control group, expression of IL-17, IL-21, IL-6, and IL-23 in mitral valve tissues was significantly increased in RHD patients (P<.05). Our study suggested that the increased expression of Th17 cell-associated cytokines might play an important role in the pathogenesis and development of RHD. Copyright © 2015 Elsevier Inc. All rights reserved.

Positron creation in superheavy quasi-molecules

International Nuclear Information System (INIS)

Mueller, B.

1976-01-01

The review of positron creation in superheavy quasi-molecules includes spontaneous positron emission from superheavy atoms, supercritical quasi-molecules, background effects, and some implications of the new ground state. 66 references

The role of the ion-molecule and molecule-molecule interactions in the formation of the two-ion average force interaction potential

CERN Document Server

Ajrian, E A; Sidorenko, S N

2002-01-01

The effect of the ion-molecule and intermolecular interactions on the formation of inter-ion average force potentials is investigated within the framework of a classical ion-dipole model of electrolyte solutions. These potentials are shown to possess the Coulomb asymptotics at large distances while in the region of mean distances they reveal creation and disintegration of solvent-shared ion pairs. The calculation results provide a qualitatively authentic physical picture which is experimentally observed in strong electrolytes solutions. In particular, an increased interaction between an ion and a molecule enhances formation of ion pairs in which the ions are separated by one solvent molecule

Doping effect on photoabsorption and charge-separation dynamics in light-harvesting organic molecule

Directory of Open Access Journals (Sweden)

Satoshi Ohmura

2016-01-01

Full Text Available Using ab-initio theoretical methods, we demonstrate possible enhancement of photo-conversion efficiency of an organic solar cell via intentional doping in molecular graphene-fullerene heterojunction [the hexabenzocoronene (HBC-triethylene glycol (TEG–C60 molecule]. Photoabsorption analysis indicates oxygen substitution into HBC leads to an extension of the spectra up to an infrared regime. A quantum-mechanical molecular dynamics simulation incorporating nonadiabatic electronic transitions reveals that a dissociated charge state (D+ and A- in the O-doped system is more stable than the pristine case due to the presence of an effective barrier by the TEG HOMO/LUMO level. We also find that oxygen doping in HBC enhances the intermolecular carrier mobility after charge separation. On the other hand, the pristine molecule undergoes rapid recombination between donor and acceptor charges at the interface. These analyses suggest that the graphene oxidation opens a new window in the application of organic super-molecules to solar cells.

Doping effect on photoabsorption and charge-separation dynamics in light-harvesting organic molecule

Energy Technology Data Exchange (ETDEWEB)

Ohmura, Satoshi, E-mail: s.ohmura.m4@cc.it-hiroshima.ac.jp [Research Center for Condensed Matter Physics, Department of Civil Engineering and Urban Design, Hiroshima Institute of Technology, Hiroshima 731-5193 (Japan); Tsuruta, Kenji [Department of Electrical and Electronic Engineering, Okayama University, Okayama 700-8530 (Japan); Shimojo, Fuyuki [Department of Physics, Kumamoto University, Kumamoto 860-8555 Japan (Japan); Nakano, Aiichiro [Collaboratory for Advanced Computing and Simulations, Department of Computer Science, Department of Physics & Astronomy, Department of Chemical Engineering & Materials Science, Department of Biological Sciences, University of Southern California, CA90089-024 (United States)

2016-01-15

Using ab-initio theoretical methods, we demonstrate possible enhancement of photo-conversion efficiency of an organic solar cell via intentional doping in molecular graphene-fullerene heterojunction [the hexabenzocoronene (HBC)-triethylene glycol (TEG)–C{sub 60} molecule]. Photoabsorption analysis indicates oxygen substitution into HBC leads to an extension of the spectra up to an infrared regime. A quantum-mechanical molecular dynamics simulation incorporating nonadiabatic electronic transitions reveals that a dissociated charge state (D{sup +} and A{sup -}) in the O-doped system is more stable than the pristine case due to the presence of an effective barrier by the TEG HOMO/LUMO level. We also find that oxygen doping in HBC enhances the intermolecular carrier mobility after charge separation. On the other hand, the pristine molecule undergoes rapid recombination between donor and acceptor charges at the interface. These analyses suggest that the graphene oxidation opens a new window in the application of organic super-molecules to solar cells.

Effect of Candida albicans and Candida dubliniensis planktonic/biofilm quorum sensing molecules on yeast morphogenesis

OpenAIRE

Henriques, Mariana; Martins, Margarida Isabel Barros Coelho; Azeredo, Joana; Oliveira, Rosário

2006-01-01

One of the aims of this work was to study the effect of farnesol, a quorum sensing molecule for Candida albicans, on morphologic inhibition of Candida dubliniensis. The second goal of this work was to confirm if Candida dubliniensis also excreted quorum sensing molecules, on both planktonic and biofilm forms. The results clearly demonstrate that Candida dubliniensis undergoes morphological alterations triggered by farnesol. It was also found that supernatants of Candida dubliniensis and Ca...

Desorption of large molecules with light-element clusters: Effects of cluster size and substrate nature

Energy Technology Data Exchange (ETDEWEB)

Delcorte, Arnaud, E-mail: arnaud.delcorte@uclouvain.be [Institute of Condensed Matter and Nanosciences - Bio and Soft Matter, Universite catholique de Louvain, Croix du Sud, 1 bte 3, B-1348 Louvain-la-Neuve (Belgium); Garrison, Barbara J. [Department of Chemistry, Penn State University, University Park, PA 16802 (United States)

2011-07-15

This contribution focuses on the conditions required to desorb a large hydrocarbon molecule using light-element clusters. The test molecule is a 7.5 kDa coil of polystyrene (PS61). Several projectiles are compared, from C{sub 60} to 110 kDa organic droplets and two substrates are used, amorphous polyethylene and mono-crystalline gold. Different aiming points and incidence angles are examined. Under specific conditions, 10 keV nanodrops can desorb PS61 intact from a gold substrate and from a soft polyethylene substrate. The prevalent mechanism for the desorption of intact and 'cold' molecules is one in which the molecules are washed away by the projectile constituents and entrained in their flux, with an emission angle close to {approx}70 deg. The effects of the different parameters on the dynamics and the underlying physics are discussed in detail and the predictions of the model are compared with other published studies.

Desorption of large molecules with light-element clusters: Effects of cluster size and substrate nature

International Nuclear Information System (INIS)

Delcorte, Arnaud; Garrison, Barbara J.

2011-01-01

This contribution focuses on the conditions required to desorb a large hydrocarbon molecule using light-element clusters. The test molecule is a 7.5 kDa coil of polystyrene (PS61). Several projectiles are compared, from C 60 to 110 kDa organic droplets and two substrates are used, amorphous polyethylene and mono-crystalline gold. Different aiming points and incidence angles are examined. Under specific conditions, 10 keV nanodrops can desorb PS61 intact from a gold substrate and from a soft polyethylene substrate. The prevalent mechanism for the desorption of intact and 'cold' molecules is one in which the molecules are washed away by the projectile constituents and entrained in their flux, with an emission angle close to ∼70 deg. The effects of the different parameters on the dynamics and the underlying physics are discussed in detail and the predictions of the model are compared with other published studies.

Toward a muon-specific electronic structure theory: effective electronic Hartree-Fock equations for muonic molecules.

Science.gov (United States)

Rayka, Milad; Goli, Mohammad; Shahbazian, Shant

2018-02-07

An effective set of Hartree-Fock (HF) equations are derived for electrons of muonic systems, i.e., molecules containing a positively charged muon, conceiving the muon as a quantum oscillator, which are completely equivalent to the usual two-component HF equations used to derive stationary states of the muonic molecules. In these effective equations, a non-Coulombic potential is added to the orthodox coulomb and exchange potential energy terms, which describes the interaction of the muon and the electrons effectively and is optimized during the self-consistent field cycles. While in the two-component HF equations a muon is treated as a quantum particle, in the effective HF equations it is absorbed into the effective potential and practically transformed into an effective potential field experienced by electrons. The explicit form of the effective potential depends on the nature of muon's vibrations and is derivable from the basis set used to expand the muonic spatial orbital. The resulting effective Hartree-Fock equations are implemented computationally and used successfully, as a proof of concept, in a series of muonic molecules containing all atoms from the second and third rows of the Periodic Table. To solve the algebraic version of the equations muon-specific Gaussian basis sets are designed for both muon and surrounding electrons and it is demonstrated that the optimized exponents are quite distinct from those derived for the hydrogen isotopes. The developed effective HF theory is quite general and in principle can be used for any muonic system while it is the starting point for a general effective electronic structure theory that incorporates various types of quantum correlations into the muonic systems beyond the HF equations.

Theory of Mind in Adults with Right Hemisphere Damage: What's the Story?

Science.gov (United States)

Weed, Ethan; McGregor, William; Nielsen, Jorgen Feldbaek; Roepstorff, Andreas; Frith, Uta

2010-01-01

Why do people with right hemisphere damage (RHD) have difficulty with pragmatics and communication? One hypothesis has been that pragmatic impairment in RHD is the result of an underlying impairment in Theory of Mind (ToM): the ability to infer the mental states of others. In previous studies evaluating ToM abilities in people with RHD,…

Reference: 730 [Arabidopsis Phenome Database[Archive

Lifescience Database Archive (English)

Full Text Available zed plasma membrane domain, but in rhd4-1 mutants, significant levels of PI(4)P were detected associated with internal membranes.... A fluorescent RHD4 fusion protein localized to membranes at the tips of growing root h...airs. We propose that RHD4 is selectively recruited to RabA4b-labeled membranes t

Remodeling of Kv1.5 channel in right atria from Han Chinese patients with atrial fibrillation.

Science.gov (United States)

Ou, Xian-hong; Li, Miao-ling; Liu, Rui; Fan, Xin-rong; Mao, Liang; Fan, Xue-hui; Yang, Yan; Zeng, Xiao-rong

2015-04-28

The incidence of atrial fibrillation (AF) in rheumatic heart diseases (RHD) is very high and increases with age. Occurrence and maintenance of AF are very complicated process accompanied by many different mechanisms. Ion-channel remodeling, including the voltage-gated potassium channel Kv1.5, plays an important role in the pathophysiology of AF. However, the changes of Kv1.5 channel expression in Han Chinese patients with RHD and AF remain poorly understood. The aim of the present study was to investigate whether the Kv1.5 channels of the right atria may be altered with RHD, age, and sex to contribute to AF. Right atrial appendages were obtained from 20 patients with normal cardiac functions who had undergone surgery, and 26 patients with AF. Subjects were picked from 4 groups: adult and aged patients in normal sinus rhythm (SR) and AF. Patients were divided into non-RHD and RHD groups or men and women groups in normal SR and AF, respectively. The expression of Kv1.5 protein and messenger RNA (mRNA) were measured using Western blotting and polymerase chain reaction (PCR) method, respectively. Compared with the SR group, the expression of Kv1.5 protein decreased significantly in the AF group. However, neither Kv1.5 protein nor KCNA5 mRNA had significant differences in adult and aged groups, non-RHD and RHD group, and men and women group of AF. The expression of Kv1.5 channel protein changes with AF but not with age, RHD, and sex in AF.

Single-Molecule Photocurrent at a Metal-Molecule-Semiconductor Junction.

Science.gov (United States)

Vezzoli, Andrea; Brooke, Richard J; Higgins, Simon J; Schwarzacher, Walther; Nichols, Richard J

2017-11-08

We demonstrate here a new concept for a metal-molecule-semiconductor nanodevice employing Au and GaAs contacts that acts as a photodiode. Current-voltage traces for such junctions are recorded using a STM, and the "blinking" or "I(t)" method is used to record electrical behavior at the single-molecule level in the dark and under illumination, with both low and highly doped GaAs samples and with two different types of molecular bridge: nonconjugated pentanedithiol and the more conjugated 1,4-phenylene(dimethanethiol). Junctions with highly doped GaAs show poor rectification in the dark and a low photocurrent, while junctions with low doped GaAs show particularly high rectification ratios in the dark (>10 3 for a 1.5 V bias potential) and a high photocurrent in reverse bias. In low doped GaAs, the greater thickness of the depletion layer not only reduces the reverse bias leakage current, but also increases the volume that contributes to the photocurrent, an effect amplified by the point contact geometry of the junction. Furthermore, since photogenerated holes tunnel to the metal electrode assisted by the HOMO of the molecular bridge, the choice of the latter has a strong influence on both the steady state and transient metal-molecule-semiconductor photodiode response. The control of junction current via photogenerated charge carriers adds new functionality to single-molecule nanodevices.

Motivations of women in Uganda living with rheumatic heart disease: A mixed methods study of experiences in stigma, childbearing, anticoagulation, and contraception.

Science.gov (United States)

Chang, Andrew Y; Nabbaale, Juliet; Nalubwama, Haddy; Okello, Emmy; Ssinabulya, Isaac; Longenecker, Christopher T; Webel, Allison R

2018-01-01

Rheumatic heart disease (RHD) is a leading cause of premature mortality in low- and middle-income countries (LMICs). Women of reproductive age are a unique and vulnerable group of RHD patients, due to increased risk of cardiovascular complications and death during pregnancy. Yet, less than 5% of women of childbearing age with RHD in LMICs use contraceptives, and one in five pregnant women with RHD take warfarin despite known teratogenicity. It is unclear whether this suboptimal contraception and anticoagulant use during pregnancy is due to lack of health system resources, limited health literacy, or social pressure to bear children. We conducted a mixed methods study of 75 women living with RHD in Uganda. Questionnaires were administered to 50 patients. Transcripts from three focus groups with 25 participants were analyzed using qualitative description methodology. Several themes emerged from the focus groups, including pregnancy as a calculated risk; misconceptions about side-effects of contraceptives and anticoagulation; reproductive decision-making control by male partners, in-laws, or physicians; abandonment of patients by male partners; and considerable stigma against heart disease patients for both their reproductive and financial limitations (often worse than that directed against HIV patients). All questionnaire respondents were told by physicians that their hearts were not strong enough to support a pregnancy. Only 14% used contraception while taking warfarin. All participants felt that society would look poorly on a woman who cannot have children due to a heart condition. To our knowledge, this is the first qualitative study of female RHD patients and their attitudes toward cardiovascular disorders and reproduction. Our results suggest that health programs targeting heart disease in LMICs must pay special attention to the needs of women of childbearing age. There are opportunities for improved family/societal education programs and community engagement

Timing and severity of immunizing diseases in rabbits is controlled by seasonal matching of host and pathogen dynamics.

Science.gov (United States)

Wells, Konstans; Brook, Barry W; Lacy, Robert C; Mutze, Greg J; Peacock, David E; Sinclair, Ron G; Schwensow, Nina; Cassey, Phillip; O'Hara, Robert B; Fordham, Damien A

2015-02-06

Infectious diseases can exert a strong influence on the dynamics of host populations, but it remains unclear why such disease-mediated control only occurs under particular environmental conditions. We used 16 years of detailed field data on invasive European rabbits (Oryctolagus cuniculus) in Australia, linked to individual-based stochastic models and Bayesian approximations, to test whether (i) mortality associated with rabbit haemorrhagic disease (RHD) is driven primarily by seasonal matches/mismatches between demographic rates and epidemiological dynamics and (ii) delayed infection (arising from insusceptibility and maternal antibodies in juveniles) are important factors in determining disease severity and local population persistence of rabbits. We found that both the timing of reproduction and exposure to viruses drove recurrent seasonal epidemics of RHD. Protection conferred by insusceptibility and maternal antibodies controlled seasonal disease outbreaks by delaying infection; this could have also allowed escape from disease. The persistence of local populations was a stochastic outcome of recovery rates from both RHD and myxomatosis. If susceptibility to RHD is delayed, myxomatosis will have a pronounced effect on population extirpation when the two viruses coexist. This has important implications for wildlife management, because it is likely that such seasonal interplay and disease dynamics has a strong effect on long-term population viability for many species. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Capillary condensation of short-chain molecules.

Science.gov (United States)

Bryk, Paweł; Pizio, Orest; Sokolowski, Stefan

2005-05-15

A density-functional study of capillary condensation of fluids of short-chain molecules confined to slitlike pores is presented. The molecules are modeled as freely jointed tangent spherical segments with a hard core and with short-range attractive interaction between all the segments. We investigate how the critical parameters of capillary condensation of the fluid change when the pore width decreases and eventually becomes smaller than the nominal linear dimension of the single-chain molecule. We find that the dependence of critical parameters for a fluid of dimers and of tetramers on pore width is similar to that of the monomer fluid. On the other hand, for a fluid of chains consisting of a larger number of segments we observe an inversion effect. Namely, the critical temperature of capillary condensation decreases with increasing pore width for a certain interval of values of the pore width. This anomalous behavior is also influenced by the interaction between molecules and pore walls. We attribute this behavior to the effect of conformational changes of molecules upon confinement.

Effects of Electric Field on the Valence-Bond Property of an Electron in a Quantum-Dot Molecule

Institute of Scientific and Technical Information of China (English)

王立民; 罗莹; 马本堃

2002-01-01

The electronic structure of the quantum-dot molecules in an electric field is investigated by the finite element method with the effective mass approximation. The numerical calculation results show that the valence bond of the quantum-dot molecule alternates between covalent bonds and ionic bonds as the electric field increases. The valence-bond property can be reflected by the oscillator strength of the intraband transition. The bound state with the highest energy level in the quantum-dot molecule gradually changes into a quasibound state when the electric field increases.

Excited states rotational effects on the behavior of excited molecules

CERN Document Server

Lim, Edward C

2013-01-01

Excited States, Volume 7 is a collection of papers that discusses the excited states of molecules. The first paper reviews the rotational involvement in intra-molecular in vibrational redistribution. This paper analyzes the vibrational Hamiltonian as to its efficacy in detecting the manifestations of intra-molecular state-mixing in time-resolved and time-averaged spectroscopic measurements. The next paper examines the temporal behavior of intra-molecular vibration-rotation energy transfer (IVRET) and the effects of IVRET on collision, reaction, and the decomposition processes. This paper also

Red Cell Alloimmunization to Rhesus Antigen Among Pregnant Women Attending a Tertiary Care Hospital in Oman

Directory of Open Access Journals (Sweden)

Tamima Al-Dughaishi

2016-01-01

Full Text Available Objectives: The detection of maternal alloimmunization against red cell antigens is vital in the management of hemolytic disease of the fetus and newborn. We sought to measure the presence of allosensitization to Rhesus D (RhD antibodies in antenatal women attending a tertiary care hospital and assess the fetal outcome in sensitized women. Methods: We conducted a retrospective review of pregnant Omani women who registered at the Sultan Qaboos University Hospital between June 2011 and June 2013. Pregnant women were tested for ABO blood type and were screened for RhD antigen and antibodies at their first antenatal clinic visit. In women who tested positive for the RhD antibodies, an antibody titer was performed to evaluate the severity of their case. Results: Data was available on 1,251 pregnant women who were managed and delivered at Sultan Qaboos University Hospital. The prevalence of RhD negative pregnant women was 7.3%. Blood group O was the most common followed by A, B, and AB. The rate of RhD negative alloimmunization was 10%, and anti-D was the most common antibody detected. There were no stillbirths or neonatal deaths. Postnatal transfusion was necessary for only one baby. Conclusions: The prevalence of RhD negativity was comparable to other Asian countries. Previous RhD alloimmunization and history of miscarriages were the most common maternal medical history.

Kondo effect in a deformed molecule coupled asymmetrically to ferromagnetic electrodes

International Nuclear Information System (INIS)

Rui-Qiang, Wang; Kai-Ming, Jiang

2009-01-01

The nonequilibrium Kondo effect is studied in a molecule quantum dot coupled asymmetrically to two ferromagnetic electrodes by employing the nonequilibrium Green function technique. The current-induced deformation of the molecule is taken into account, modeled as interactions with a phonon system, and phonon-assisted Kondo satellites arise on both sides of the usual main Kondo peak. In the antiparallel electrode configuration, the Kondo satellites can be split only for the asymmetric dot-lead couplings, distinguished from the parallel configuration where splitting also exists, even though it is for symmetric case. We also analyze how to compensate the splitting and restore the suppressed zero-bias Kondo resonance. It is shown that one can change the TMR ratio significantly from a negative dip to a positive peak only by slightly modulating a local external magnetic field, whose value is greatly dependent on the electron–phonon coupling strength. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Spectroscopy and Chemistry of Cold Molecules

Science.gov (United States)

Momose, Takamasa

2012-06-01

Molecules at low temperatures are expected to behave quite differently from those at high temperatures because pronounced quantum effects emerge from thermal averages. Even at 10 K, a significant enhancement of reaction cross section is expected due to tunneling and resonance effects. Chemistry at this temperature is very important in order to understand chemical reactions in interstellar molecular clouds. At temperatures lower than 1 K, collisions and intermolecular interactions become qualitatively different from those at high temperatures because of the large thermal de Broglie wavelength of molecules. Collisions at these temperatures must be treated as the interference of molecular matter waves, but not as hard sphere collisions. A Bose-Einstein condensate is a significant state of matter as a result of coherent matter wave interaction. Especially, dense para-H_2 molecules are predicted to become a condensate even around 1 K. A convenient method to investigate molecules around 1 K is to dope molecules in cold matrices. Among various matrices, quantum hosts such as solid para-H_2 and superfluid He nano-droplets have been proven to be an excellent host for high-resolution spectroscopy. Rovibrational motion of molecules in these quantum hosts is well quantized on account of the weak interactions and the softness of quantum environment. The linewidths of infrared spectra of molecules in the quantum hosts are extremely narrow compared with those in other matrices. The sharp linewidths allow us to resolve fine spectral structures originated in subtle interactions between guest and host molecules. In this talk, I will describe how the splitting and lineshape of high-resolution spectra of molecules in quantum hosts give us new information on the static and dynamical interactions of molecules in quantum medium. The topics include dynamical response of superfluid environment upon rotational excitation, and possible superfluid phase of para-H_2 clusters. I will also

NATO Advanced Study Institute on Relativistic and Electron Correlation Effects in Molecules and Solids

CERN Document Server

1994-01-01

The NATO Advanced Study Institute (ASI) on "R@lativistic and Electron Correlation Effects in Molecules and Solids", co-sponsored by Simon Fraser University (SFU) and the Natural Sciences and Engineering Research Council of Canada (NSERC) was held Aug 10- 21, 1992 at the University of British Columbia (UBC), Vancouver, Canada. A total of 90 lecturers and students with backgrounds in Chemistry, Physics, Mathematics and various interdisciplinary subjects attended the ASI. In my proposal submitted to NATO for financial support for this ASI, I pointed out that a NATO ASI on the effects of relativity in many-electron systems was held ten years ago, [See G.L. Malli, (ed) Relativistic Effects in Atoms, Molecules and Solids, Plenum Press, Vol B87, New York, 1983]. Moreover, at a NATO Advanced Research Workshop (ARW) on advanced methods for molecular electronic structure "an assessment of state-of­ the-art of Electron Correlation ... " was carried out [see C.E. Dykstra, (ed), Advanced Theories and Computational Approa...

Hybrid molecule/superconductor assemblies

International Nuclear Information System (INIS)

McDevitt, J.T.; Haupt, S.G.; Riley, D.R.; Zhao, J.; Zhou, J.P., Jones, C.

1993-01-01

The fabrication of electronic devices from molecular materials has attracted much attention recently. Schottky diodes, molecular transistors, metal-insulator-semiconductor diodes, MIS field effect transistors and light emitting diodes have all been prepared utilizing such substances. The active elements in these devices have been constructed by depositing the molecular phase onto the surface of a metal, semiconductor or insulating substrate. With the recent discovery of high temperature superconductivity, new opportunities now exist for the study of molecule/superconductor interactions as well as for the construction of novel hybrid molecule/superconductor devices. In this paper, methods for preparing the initial two composite molecule/semiconductor devices will be reported. Consequently, light sensors based on dye-coated superconductor junctions as well as molecular switches fashioned from conductive polymer coated superconductor junctions as well as molecular switches fashioned from conductive polymer coated superconductor microbridges will be discussed. Moreover, molecule/superconductor energy and electron transfer phenomena will be illustrated also for the first time

Controlling single-molecule junction conductance by molecular interactions

Science.gov (United States)

Kitaguchi, Y.; Habuka, S.; Okuyama, H.; Hatta, S.; Aruga, T.; Frederiksen, T.; Paulsson, M.; Ueba, H.

2015-01-01

For the rational design of single-molecular electronic devices, it is essential to understand environmental effects on the electronic properties of a working molecule. Here we investigate the impact of molecular interactions on the single-molecule conductance by accurately positioning individual molecules on the electrode. To achieve reproducible and precise conductivity measurements, we utilize relatively weak π-bonding between a phenoxy molecule and a STM-tip to form and cleave one contact to the molecule. The anchoring to the other electrode is kept stable using a chalcogen atom with strong bonding to a Cu(110) substrate. These non-destructive measurements permit us to investigate the variation in single-molecule conductance under different but controlled environmental conditions. Combined with density functional theory calculations, we clarify the role of the electrostatic field in the environmental effect that influences the molecular level alignment. PMID:26135251

Synthesis and study of the optical properties of dielectric Bragg reflectors infiltrated with 6G-Rhodamine

International Nuclear Information System (INIS)

Gómez-Barojas, E; Aca-López, V; Luna-López, J A; Sánchez-Mora, E; Silva-González, R

2014-01-01

We report the study of the optical properties of 6G-Rhodamine (Rhd) infiltrated porous silicon dielectric Bragg reflectors (DBRs) with 31 constituent periods. The DBRs were obtained by an electrochemical anodizing process of Si in a two electrodes Teflon cell. The porosity was determined by gravimetric measurements on single Porous silicon (PSi) layers. Based on the characterization results of single layers the DBRs were synthesized. After anodizing, the DBRs were silanized with a 3-mercaptopropyltrimethoxysilane solution and functionalized with Rhd solutions at different concentrations. Cross section scanning electron micrographs show that the DBRs synthesis was successful. After each preparation step, Reflectance and Fluorescence (FL) spectra were recorded. These spectra show that as the Rhd concentration in solution is increased the stop band intensity as well as the FL intensity are enhanced due to constructive interference effects

Clinical chemistry, haematology, immune response and histological evaluation of rabbits after immunisation and challenge with rabbit haemorrhagic disease (RHD virus

Directory of Open Access Journals (Sweden)

C. A. Stancu

2017-12-01

Full Text Available Following their immunisation and infection with a VSHI-CN-6 viral strain, a group of 15 rabbits were examined in a study of Rabbit Haemorrhagic Disease (RHD. Serum samples were collected from the external ear vein at 0, 15, 30 and 60 days post-immunisation. The recorded platelet numbers were closer to the lower physiological limit, indicating a mild thrombocytopenia, with values ranging from 26.6 to 30.43×104/mm3. The phagocytic index revealed significant differences (P<0.001 between the mean values obtained before vaccination (day 0 and the 3 post-vaccination measurements, confirming the increase in phagocytic capacity after immunisation. Additionally, the serum lysozyme average value equalled 9.14 mg/mL post-vaccination. The analysis of variance revealed significant statistical differences (P<0.05 between the average values obtained before vaccination (0 and the post-vaccination values, measured on day 14 and 30, respectively. The morphology of the samples collected from the main organs involved in immune protection, spleen and gastric and portal lymph nodes highlighted changes corresponding to the post-vaccination immunological response. The white pulp of the spleen appeared as a diffuse lymphoid tissue, presenting with primary and secondary lymphoid follicles. The ratio of white/red pulp was in favour of the white pulp and multiple lymphoid follicles were present, indicating their reactivation. In the medullary area of gastric and portal lymph nodes, narrow lymphoid cords, circumscribed by relatively large lymphatic sinuses, and well defined lymphocytolysis were observed. Moreover, the exudate and lymphoid follicles during activation were noted in the cortical area. Furthermore, the inflammatory processes were identified, morphologically manifested by the thickening of connective tissue in the lymph node capsule, dilacerations of the connective fibres and the presence of light acidophilic serous exudate with rare inflammatory cells (serous

Air pollution in early life and adult mortality from chronic rheumatic heart disease.

Science.gov (United States)

Phillips, David I W; Osmond, Clive; Williams, Martin L; Jones, Alexander

2017-08-01

Chronic rheumatic heart disease (RHD) remains a globally important cause of heart disease. The reasons for the continuing high prevalence of this disease are obscure, but it may have its origins in the poor social and economic conditions with which the disease has been consistently and strongly linked. Mortality studies from the UK have suggested the importance of adverse environmental factors in early life; these studies demonstrated specific geographical associations between high rates of chest infection during infancy and subsequent RHD. They raised the possibility that early air pollution, which is known to be strongly linked with chest infection during infancy, may predispose to RHD. We related estimates of air pollution and social conditions developed by Daly in 1951-52 for 78 urban areas in England and Wales to their subsequent RHD mortality rates at ages 35-74 in men and women during 1993-2012. There were strong relationships between domestic air pollution and RHD [relative risk per standard deviation (SD) increase in pollution 1.168, 95% confidence interval (CI): 1.128 to 1.210, P air pollution association was independent of these; only overcrowding was separately linked with RHD. We present the first evidence of an association between air pollution in early life and RHD. Although there are several limitations to this study, the strength and consistency of the results, together with their biological plausibility, suggest a causal link. This deserves attention because it may have important consequences for the control of RHD in resource-poor countries where widespread use of biomass fuels and domestic pollution remain a problem. © The Author 2016; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association

Anti-D reagents should be chosen accordingly to the prevalence of D variants in the obstetric population.

Science.gov (United States)

Lukacevic Krstic, Jelena; Dajak, Slavica; Bingulac-Popovic, Jasna; Dogic, Vesna; Mratinovic-Mikulandra, Jela

2018-03-01

Resolving ambiguous results of D antigen typing is crucial for appropriate and rational administration of anti-D immunoprophylaxis and transfusion practice in obstetric population. The aim of the study was to establish selection criteria of anti-D reagents for our population. A total of 12 689 samples from primiparous women in Split-Dalmatia County, Croatia, were typed for RhD antigen during the period of 5 years. Ambiguous results were submitted to additional serologic investigation and genotyping. RHD genotyping was performed by commercial genotyping kits (Ready Gene weak D ® and Ready gene CDE, Inno-Train, Kronberg, Germany). Relative frequencies and accompanying 95% confidence intervals were used to estimate the prevalence of variants. The prevalence of D variants was 0.42% (95% CI 0.31; 0.53). The most common partial D variant was D Va (RHD*05.05), with the prevalence of 0.08% (95% CI 0.03; 0.13). All weak D variants were weak D types 1, 2 and 3 (RHD*weak D type 1, RHD*weak D type 2, RHD*weak D type 3). Weak D samples were distinguishable from partial D in routine typing due to the difference in reactivity of partial D samples with clones D7B8 and RUM-1. Cell line RUM-1 gives weak or negative reactions with partial DVa category. The most common partial D variant in our population is DVa. It is recommended to use cell lines which do not strongly agglutinate DVa variant in routine RhD typing. The appropriate choice of reagents will enable the serology methods to recognize the cases in which RHD genotyping is required. © 2017 Wiley Periodicals, Inc.

Effect of different substitution position on the switching behavior in single-molecule device with carbon nanotube electrodes

Science.gov (United States)

Yang, Jingjuan; Han, Xiaoxiao; Yuan, Peipei; Bian, Baoan; Wang, Yixiang

2018-01-01

We investigate the electronic transport properties of dihydroazulene (DHA) and vinylheptafulvene (VHF) molecule sandwiched between two carbon nanotubes using density functional theory and non-equilibrium Green's function. The device displays significantly switching behavior between DHA and VHF isomerizations. It is found the different substitution position of F in the molecule influences the switching ratio of device, which is analyzed by transmission spectra and molecular projected self-consistent Hamiltonian. The observed negative differential resistance effect is explained by transmission spectra and transmission eigenstates of transmission peak in the bias window. The observed reverse of current in VHF form in which two H atoms on the right side of the benzene ring of the molecule are replaced by F is explained by transmission spectra and molecule-electrode coupling with the varied bias. The results suggest that the reasonable substitution position of molecule may improve the switching ratio, displaying a potential application in future molecular circuit.

Theory of tunneling ionization of molecules: Weak-field asymptotics including dipole effects

DEFF Research Database (Denmark)

Tolstikhin, Oleg I.; Morishita, Toru; Madsen, Lars Bojer

2011-01-01

The formulation of the parabolic adiabatic expansion approach to the problem of ionization of atomic systems in a static electric field, originally developed for the axially symmetric case [ Phys. Rev. A 82 023416 (2010)], is generalized to arbitrary potentials. This approach is used to rederive...... the asymptotic theory of tunneling ionization in the weak-field limit. In the atomic case, the resulting formulas for the ionization rate coincide with previously known results. In addition, the present theory accounts for the possible existence of a permanent dipole moment of the unperturbed system and, hence......, applies to polar molecules. Accounting for dipole effects constitutes an important difference of the present theory from the so-called molecular Ammosov-Delone-Krainov theory. The theory is illustrated by comparing exact and asymptotic results for a set of model polar molecules and a realistic molecular...

Teaching focused echocardiography for rheumatic heart disease screening

Directory of Open Access Journals (Sweden)

Daniel Engelman

2015-01-01

Full Text Available Screening for rheumatic heart disease (RHD requires workers skilled in echocardiography, which typically involves prolonged, specialized training. Task shifting echocardiographic screening to nonexpert health workers may be a solution in settings with limited human resources. An 8-week training program was designed to train health workers without any prior experience in focused echocardiography for RHD screening. Seven health workers participated. At the completion of training, the health workers performed unsupervised echocardiography on 16 volunteer children with known RHD status. A pediatric cardiologist assessed image quality. Participants provided qualitative feedback. The quality of echocardiograms were high at completion of training (55 of 56 were adequate for diagnosis and all cases of RHD were identified. Feedback was strongly positive. Training health workers to perform focused echocardiography for RHD screening is feasible. After systematic testing for accuracy, this training program could be adapted in other settings seeking to expand echocardiographic capabilities.

Teaching focused echocardiography for rheumatic heart disease screening

International Nuclear Information System (INIS)

Engelman, Daniel; Kado, Joseph H; Reményi, Bo; Colquhoun, Samantha M; Watson, Caroline; Rayasidamu, Sera C; Steer, Andrew C

2005-01-01

Screening for rheumatic heart disease (RHD) requires workers skilled in echocardiography, which typically involves prolonged, specialized training. Task shifting echocardiographic screening to nonexpert health workers may be a solution in settings with limited human resources. An 8-week training program was designed to train health workers without any prior experience in focused echocardiography for RHD screening. Seven health workers participated. At the completion of training, the health workers performed unsupervised echocardiography on 16 volunteer children with known RHD status. A pediatric cardiologist assessed image quality. Participants provided qualitative feedback. The quality of echocardiograms were high at completion of training (55 of 56 were adequate for diagnosis) and all cases of RHD were identified. Feedback was strongly positive. Training health workers to perform focused echocardiography for RHD screening is feasible. After systematic testing for accuracy, this training program could be adapted in other settings seeking to expand echocardiographic capabilities

Effects of Environmental Factors and Metallic Electrodes on AC Electrical Conduction Through DNA Molecule.

Science.gov (United States)

Abdalla, S; Obaid, A; Al-Marzouki, F M

2017-12-01

Deoxyribonucleic acid (DNA) is one of the best candidate materials for various device applications such as in electrodes for rechargeable batteries, biosensors, molecular electronics, medical- and biomedical-applications etc. Hence, it is worthwhile to examine the mechanism of charge transport in the DNA molecule, however, still a question without a clear answer is DNA a molecular conducting material (wire), semiconductor, or insulator? The answer, after the published data, is still ambiguous without any confirmed and clear scientific answer. DNA is found to be always surrounded with different electric charges, ions, and dipoles. These surrounding charges and electric barrier(s) due to metallic electrodes (as environmental factors (EFs)) play a substantial role when measuring the electrical conductivity through λ-double helix (DNA) molecule suspended between metallic electrodes. We found that strong frequency dependence of AC-complex conductivity comes from the electrical conduction of EFs. This leads to superimposing serious incorrect experimental data to measured ones. At 1 MHz, we carried out a first control experiment on electrical conductivity with and without the presence of DNA molecule. If there are possible electrical conduction due to stray ions and contribution of substrate, we will detected them. This control experiment revealed that there is an important role played by the environmental-charges around DNA molecule and any experiment should consider this role. We have succeeded to measure both electrical conductivity due to EFs (σ ENV ) and electrical conductivity due to DNA molecule (σ DNA ) independently by carrying the measurements at different DNA-lengths and subtracting the data. We carried out measurements as a function of frequency (f) and temperature (T) in the ranges 0.1 Hz molecule from all EFs effects that surround the molecule, but also to present accurate values of σ DNA and the dielectric constant of the molecule ε' DNA as a

New Perspectives on the Search for a Parity Violation Effect in Chiral Molecules

Science.gov (United States)

Auguste, F.; Tokunaga, S. K.; Shelkovnikov, A.; Daussy, C.; Amy-Klein, A.; Chardonnet, C.; Darquie, B.

2013-06-01

Parity violation (PV) effects have so far never been observed in chiral molecules. Originating from the weak interaction, PV should lead to frequency differences in the rovibrational spectra of the two enantiomers of a chiral molecule. However the smallness of the effect represents a very difficult experimental challenge. We propose to compare the rovibrational spectra (around 10 μm) of two enantiomers, recorded using the ultra-high resolution spectroscopy technique of Doppler-free two-photon Ramsey interferometry in a supersonic molecular beam. With an alternate beam of left- and right-handed molecules and thanks to our expertise in the control of the absolute frequency of the probe CO_2 lasers, we should reach a fractional sensitivity better around 10^{-15} (a few tens of millihertz), on the frequency difference between enantiomers. We will review our latest results on the high-resolution spectroscopy, either in cell or in a supersonic beam, of methyltrioxorhenium. B. Darquié, C. Stoeffler, A. Shelkovnikov, C. Daussy, A. Amy-Klein, C. Chardonnet, S. Zrig, L. Guy, J. Crassous, P. Soulard, P. Asselin, T. R. Huet, P. Schwerdtfeger, R. Bast and T. Saue, Chirality 22, 870 (2010). C. Stoeffler, B. Darquié, A. Shelkovnikov, C. Daussy, A. Amy-Klein, C. Chardonnet, L. Guy, J. Crassous, T. R. Huet, P. Soulard and P. Asselin, Phys. Chem. Chem. Phys. 13, 854 (2011). N. Saleh, S. Zrig, L. Guy, R. Bast, T. Saue, B. Darquié and J. Crassous, submitted to Phys. Chem. Chem. Phys. (2013).

Quantum Effects in Molecule-Based Nanomagnets

Science.gov (United States)

Hill, Stephen

2005-11-01

Research into molecule-based-magnets has made immense strides in recent years, with the discoveries of all organic molecular magnets, room temperature 3D ordered permanent magnets, and single-molecule magnets (SMMs), the latter exhibiting a host of spectacular quantum phenomena; for a review, see ref. [1]. SMMs represent a molecular approach to nanoscale and sub-nanoscale magnetic particles. They offer all of the advantages of molecular chemistry as well as displaying the superparamagnetic properties of mesoscale magnetic particles of much larger dimensions. They also straddle the interface between classical and quantum behavior; for example, they exhibit quantum tunneling of their magnetization. I will give a general introduction to this area of research, followed by an overview of recent results obtained using high-frequency (40-800 GHz) electron paramagnetic resonance techniques developed at the University of Florida. These results include: an elucidation of the role of molecular symmetry in the magnetic quantum tunneling phenomenon [2]; and the observation of quantum entanglement between pairs of nanomagnets within a supramolecular dimer [3]. 1. D. Gatteschi and R. Sessoli, Angew. Chem. 42, 268 (2003). 2. E. del Barco et al., J. Low Temp. Phys. 140, 119-174 (2005). 3. S. Hill et al., Science 302, 1015 (2003).

Growing interstellar molecules with ion-molecule reactions

International Nuclear Information System (INIS)

Bohme, D.K.

1989-01-01

Laboratory measurements of gas-phase ion-molecule reactions continue to provide important insights into the chemistry of molecular growth in interstellar environments. It is also true that the measurements are becoming more demanding as larger molecules capture our interest. While some of these measurements are motivated by current developments in chemical models of interstellar environments or by new molecular observations by astronomers, others explore novel chemistry which can lead to predictions of new interstellar molecules. Here the author views the results of some recent measurements, taken in the Ion Chemistry Laboratory at York University with the SIFT technique, which address some of the current needs of modellers and observers and which also provide some new fundamental insight into molecular growth, particularly when it occurs in the presence of large molecules such as PAH molecules which are now thought to have a major influence on the chemistry of interstellar environments in which they are present

The clinical characteristics of adults with rheumatic heart disease in Yangon, Myanmar: An observational study.

Science.gov (United States)

Myint, Nan Phyu Sin Toe; Aung, Ne Myo; Win, Myint Soe; Htut, Thu Ya; Ralph, Anna P; Cooper, David A; Nyein, Myo Lwin; Kyi, Mar Mar; Hanson, Josh

2018-01-01

Rheumatic heart disease (RHD) is a major cause of premature death in low and middle-income countries. The greatest barrier to RHD control is neglect of the disease in national health policies and a lack of prevalence data that might inform control efforts. Myanmar is making remarkable progress against many infectious diseases, but there are almost no data to define the clinical burden of RHD in the country. This prospective audit was performed in an adult medical ward of a tertiary-referral hospital in Yangon, to gain an insight into the prevalence of RHD in Myanmar. All patients admitted to the ward between May 1, 2016 and April 30, 2017 were eligible for enrolment. RHD was confirmed in 96 patients who were admitted on 134 occasions, representing 1.1% of the 12,172 adult medical admissions during the study period. This compared with 410 (3.4%) admissions with HIV and 14 (0.1%) with malaria. Patients with RHD had a median age of 44 years (interquartile range: 35-59); 70 (73%) were female. Only one patient had ever had surgery despite 79 (82%) meeting criteria for intervention; 54 (56%) patients were not receiving any regular clinician review. Prior to hospitalisation only 18 (19%) patients were receiving regular penicillin. Only 8 (19%) of the 42 women Myanmar. A national RHD programme would improve patient care, reducing morbidity and mortality from this preventable disease.

Absolute carrier phase effects in the two-color excitation of dipolar molecules

International Nuclear Information System (INIS)

Brown, Alex; Meath, W.J.; Kondo, A.E.

2002-01-01

The pump-probe excitation of a two-level dipolar (d≠0) molecule, where the pump frequency is tuned to the energy level separation while the probe frequency is extremely small, is examined theoretically as an example of absolute phase control of excitation processes. The state populations depend on the probe field's absolute carrier phase but are independent of the pump field's absolute carrier phase. Interestingly, the absolute phase effects occur for pulse durations much longer and field intensities much weaker than those required to see such effects in single pulse excitation

Emergence of a new lagovirus related to rabbit haemorrhagic disease virus

OpenAIRE

Le Gall-Recule, Ghislaine; Lavazza, Antonio; Marchandeau, Stephane; Bertagnoli, Stéphane; Zwingelstein, Francoise; Cavadini, Patrizia; Martinelli, Nicola; Lombardi, Guerino; Guérin, Jean-Luc; Lemaitre, Evelyne; Decors, Anouk; Boucher, Samuel; Le Normand, Bernadette; Capucci, Lorenzo

2013-01-01

Since summer 2010, numerous cases of Rabbit Haemorrhagic Disease (RHD) have been reported in north-western France both in rabbitries, affecting RHD-vaccinated rabbits, and in wild populations. We demonstrate that the aetiological agent was a lagovirus phylogenetically distinct from other lagoviruses and which presents a unique antigenic profile. Experimental results show that the disease differs from RHD in terms of disease duration, mortality rates, higher occurrence of subacute/chronic form...

Molecular Wring Resonances in Chain Molecules

DEFF Research Database (Denmark)

Bohr, Henrik; Brunak, Søren; Bohr, Jakob

1997-01-01

It is shown that the eigenfrequency of collective twist excitations in chain molecules can be in the megahertz and gigahertz range. Accordingly, resonance states can be obtained at specific frequencies, and phenomena that involve structural properties can take place. Chain molecules can alter the...... their conformation and their ability to function, and a breaking of the chain can result. It is suggested that this phenomenon forms the basis for effects caused by the interaction of microwaves and biomolecules, e.g. microwave assisted hydrolysis of chain molecules....

Molecule nanoweaver

Science.gov (United States)

Gerald, II; Rex, E [Brookfield, IL; Klingler, Robert J [Glenview, IL; Rathke, Jerome W [Homer Glen, IL; Diaz, Rocio [Chicago, IL; Vukovic, Lela [Westchester, IL

2009-03-10

A method, apparatus, and system for constructing uniform macroscopic films with tailored geometric assemblies of molecules on the nanometer scale. The method, apparatus, and system include providing starting molecules of selected character, applying one or more force fields to the molecules to cause them to order and condense with NMR spectra and images being used to monitor progress in creating the desired geometrical assembly and functionality of molecules that comprise the films.

Generalized transition state theory. Quantum effects for collinear reactions of hydrogen molecules and isotopically substituted hydrogen molecules

International Nuclear Information System (INIS)

Garrett, B.C.; Truhlar, D.G.

1979-01-01

Canonical variational transition state theory, microcanonical variational transition state theory, and Miller's unified statistical theory were used in an attempt to correct two major deficiencies of the conventional transition state theory. These are: (1) the necessity of extra assumptions to include quantum mechanical tunneling effects and (2) the fundamental assumption that trajectories crossing a dividing surface in phase space proceed directly to products. The accuracy of these approximate methods were tested by performing calculations for several collinear reactions of hydrogen, deuterium, chlorine, or iodine, with five isotopes of hydrogen molecules and comparison of these results with those from accurate quantitative calculations of the reaction probabilities as functions of energy and of the thermal rate constants as functions of temperature. 49 references, 28 figures, 17 tables

The effect of gold nanoparticles on exchange processes in collision complexes of triplet and singlet oxygen molecules with excited eosin molecules

Science.gov (United States)

Bryukhanov, V. V.; Minaev, B. M.; Tsibul'nikova, A. V.; Slezhkin, V. A.

2015-07-01

We have studied exchange processes in contact complexes of triplet eosin molecules with oxygen molecules in the triplet (3Σ{/g -}) and singlet (1Δ g ) states in thin polyvinylbutyral films in the presence of gold nanoparticles. Upon resonant excitation of surface plasmons in gold nanoparticles into the absorption band of eosin molecules-singlet oxygen sensitizers-we have obtained an increase in the intensity of the delayed fluorescence and an increase in the lifetime of the dye with simultaneous quenching of the luminescence of singlet oxygen. The kinetics of the delayed fluorescence of the dye as a result of singlet-triplet annihilation of triplet eosin molecules with singlet oxygen molecules has been investigated. To compare theoretical and experimental data, we have numerically simulated energy transfer processes. Rate constants of energy transfer and of singlet-triplet annihilation, as well as quenching constants of triplet states of the dye by molecular oxygen, have been calculated. Luminescence quantum yield 1Δ g of polyvinylbutyral has been estimated. We have analyzed quantum-chemically electronic mechanisms of singlet-triplet annihilation of oxygen and eosin.

Spin tunneling in magnetic molecules

Science.gov (United States)

Kececioglu, Ersin

In this thesis, we will focus on spin tunneling in a family of systems called magnetic molecules such as Fe8 and Mn12. This is comparatively new, in relation to other tunneling problems. Many issues are not completely solved and/or understood yet. The magnetic molecule Fe 8 has been observed to have a rich pattern of degeneracies in its magnetic spectrum. We focus on these degeneracies from several points of view. We start with the simplest anisotropy Hamiltonian to describe the Fe 8 molecule and extend our discussion to include higher order anisotropy terms. We give analytical expressions as much as we can, for the degeneracies in the semi-classical limit in both cases. We reintroduce jump instantons to the instanton formalism. Finally, we discuss the effect of the environment on the molecule. Our results, for all different models and techniques, agree well with both experimental and numerical results.

Pendant unit effect on electron tunneling in U-shaped molecules

International Nuclear Information System (INIS)

Liu Min; Chakrabarti, Subhasis; Waldeck, David H.; Oliver, Anna M.; Paddon-Row, Michael N.

2006-01-01

The electron transfer reactions of three U-shaped donor-bridge-acceptor molecules with different pendant groups have been studied in different solvents as a function of temperature. Analysis of the electron transfer kinetics in nonpolar and weakly polar solvents provides experimental reaction Gibbs energies that are used to parameterize a molecular solvation model. This solvation model is then used to predict energetic parameters in the electron transfer rate constant expression and allow the electronic coupling between the electron donor and electron acceptor groups to be determined from the rate data. The U-shaped molecules differ by alkylation of the aromatic pendant group, which lies in the 'line-of-sight' between the donor and acceptor groups. The findings show that the electronic coupling through the pendant group is similar for these molecules

Evolution, evidence and effect of secondary prophylaxis against rheumatic fever

Directory of Open Access Journals (Sweden)

Rosemary Wyber

2015-01-01

Full Text Available The association between group A streptococcal infection and rheumatic fever (RF was established in the early 20 th century. At the time, RF and subsequent rheumatic heart disease (RHD were an untreatable scourge of young people in developed and developing countries. Resultingly, research efforts to understand, treat and prevent the disease were widepread. The development of antibiotics in the 1930s offered therapeutic promise, although antibotic treatment of acute RF had little impact. Improved understanding of the post-infectious nature of RF prompted attempts to use antibiotics prophylactically. Regular doses of sulphonamide antibiotics following RF appeared to reduce disease progression to RHD. Development of penicillin and later, benzathine penicillin G, was a further thereputic advance in the 1950s. No new prophylactic options against RF have emerged in the intervening 60 years, and delivery of regularly scheduled BPG injections remains a world wide challenge.

Memory effects in single-molecule spectroscopy

International Nuclear Information System (INIS)

Schmitt, Daniel T.; Schulz, Michael; Reineker, Peter

2007-01-01

From the time series of LH2 optical single-molecule fluorescence excitation spectra of Rhodospirillum molischianum the memory function of the Mori-Zwanzig equation for the optical intensity is derived numerically. We show that the time dependence of the excited states is determined by at least three different non-Markovian stochastic processes with decay constants for the Mori-Zwanzig kernel on the order of 1-5min -1 . We suggest that this decay stems from the conformational motion of the protein scaffold of LH2

Effects of a donor on the bond property of quantum-dot molecules

Institute of Scientific and Technical Information of China (English)

Wang Li-Min; Luo Ying; Ma Ben-Kun; Duan Su-Qing; Zhao Xian-Geng

2004-01-01

Within the framework of effective mass approximation, we have calculated the electronic structure of the two laterally coupled quantum dots with a donor by the finite element method. The calculated results show that the bond states of quantum-dot molecules are quite sensitive to the donor positions. By varying the donor position, the transition from covalent to ionic bond state is realized for some electronic states. Some extreme cases are also discussed for comparison.

Coulomb Repulsion Effect in Two-electron Non-adiabatic Tunneling through a One-level redox Molecule

DEFF Research Database (Denmark)

Medvedev, Igor M.; Kuznetsov, Alexander M.; Ulstrup, Jens

2009-01-01

We investigated Coulomb repulsion effects in nonadiabatic (diabatic) two-electron tunneling through a redox molecule with a single electronic level in a symmetric electrochemical contact under ambient conditions, i.e., room temperature and condensed matter environment. The electrochemical contact...

Beneficial effects of bacteria-plant communication based on quorum sensing molecules of the N-acyl homoserine lactone group.

Science.gov (United States)

Schikora, Adam; Schenk, Sebastian T; Hartmann, Anton

2016-04-01

Bacterial quorum sensing (QS) mechanisms play a crucial role in the proper performance and ecological fitness of bacterial populations. Many key physiological processes are regulated in a QS-dependent manner by auto-inducers, like the N-acyl homoserine lactones (AHLs) in numerous Gram-negative bacteria. In addition, also the interaction between bacteria and eukaryotic hosts can be regulated by AHLs. Those mechanisms gained much attention, because of the positive effects of different AHL molecules on plants. This positive impact ranges from growth promotion to induced resistance and is quite contrasting to the rather negative effects observed in the interactions between bacterial AHL molecules and animals. Only very recently, we began to understand the molecular mechanisms underpinning plant responses to AHL molecules. In this review, we gathered the latest information in this research field. The first part gives an overview of the bacterial aspects of quorum sensing. Later we focus on the impact of AHLs on plant growth and AHL-priming, as one of the most understood phenomena in respect to the inter-kingdom interactions based on AHL-quorum sensing molecules. Finally, we discuss the potential benefits of the understanding of bacteria-plant interaction for the future agricultural applications.

Experimental decoherence in molecule interferometry

International Nuclear Information System (INIS)

Hackermueller, L.; Hornberger, K.; Stibor, A.; Zeilinger, A.; Arndt, M.; Kiesewetter, G.

2005-01-01

Full text: We present three mechanisms of decoherence that occur quite naturally in matter wave interferometer with large molecules. One way molecules can lose coherence is through collision with background gas particles. We observe a loss of contrast with increasing background pressure for various types of gases. We can understand this phenomenon quantitatively with a new model for collisional decoherence which corrects older models by a factor of 2 π;. The second experiment studies the thermal emission of photons related to the high internal energy of the interfering molecules. When sufficiently many or sufficiently short photons are emitted inside the interferometer, the fringe contrast is lost. We can continuously vary the temperature of the molecules and compare the loss of contrast with a model based on decoherence theory. Again we find good quantitative agreement. A third mechanism that influences our interference pattern is dephasing due to vibrations of the interference gratings. By adding additional vibrations we study this effect in more detail. (author)

Effect resonance radiation transfer of excitation porous silicon to I sub 2 molecules sorbed in pores

CERN Document Server

Zakharchenko, K V; Kuznetsov, M B; Chistyakov, A A; Karavanskij, V A

2001-01-01

One studies the effect of resonance radiation-free transfer of electronic excitation between silicon nanocrystals and iodine molecules sorbed in pores. The experiment procedure includes laser-induced luminescence and laser desorption mass spectrometry. One analyzes photoluminescence spectra prior to and upon iodine sorption. Excitation of iodine through the mechanism of resonance transfer is determined to result in desorption of the iodine sorbed molecules with relatively high kinetic energies (3-1 eV). One evaluated the peculiar distance of resonance transfer the approximate value of which was equal to 2 nm

The use of β-blockade to control heart rate during whole body hyperthermia (WBH): A toxicity study in the dog

International Nuclear Information System (INIS)

Robins, H.I.; Hugander, A.; Besozzi, M.; Grossman, J.

1987-01-01

Radionuclide ventriculography as well as invasive hemodynamic monitoring was used to study the cardiovascular changes in the dog during 42 0 C WBH, i.e., heart rate, blood pressure, cardiac output, stroke volume and ejection fraction. WBH was delivered by a radiant heat device (RHD). Results obtained agree qualitatively and quantitatively with changes observed in WBH-RHD studies done in pigs and humans. The authors elected to study the effect of propranolol in dogs during 42 0 C WBH in order to evaluate this drug's potential use in human cancer patients who are ineligible for WBH because of coronary artery disease. The results show that the level of β-blockade needed to control heart rate during WBH produces acute cardiovascular decompensation. The authors believe these results represent a contraindication to drug-induced β-blockade during RHD-WBH. Beyond its clinical implications for human cancer patients, this experience with the dog as an animal model for WBH recommends its use for further physiological and pharmacological studies

DNA-psoralen interaction: a single molecule experiment.

Science.gov (United States)

Rocha, M S; Viana, N B; Mesquita, O N

2004-11-15

By attaching one end of a single lambda-DNA molecule to a microscope coverslip and the other end to a polystyrene microsphere trapped by an optical tweezers, we can study the entropic elasticity of the lambda-DNA by measuring force versus extension as we stretch the molecule. This powerful method permits single molecule studies. We are particularly interested in the effects of the photosensitive drug psoralen on the elasticity of the DNA molecule. We have illuminated the sample with different light sources, studying how the different wavelengths affect the psoralen-DNA linkage. To do this, we measure the persistence length of individual DNA-psoralen complexes.

Stochastic models for surface diffusion of molecules

Energy Technology Data Exchange (ETDEWEB)

Shea, Patrick, E-mail: patrick.shea@dal.ca; Kreuzer, Hans Jürgen [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia B3H 3J5 (Canada)

2014-07-28

We derive a stochastic model for the surface diffusion of molecules, starting from the classical equations of motion for an N-atom molecule on a surface. The equation of motion becomes a generalized Langevin equation for the center of mass of the molecule, with a non-Markovian friction kernel. In the Markov approximation, a standard Langevin equation is recovered, and the effect of the molecular vibrations on the diffusion is seen to lead to an increase in the friction for center of mass motion. This effective friction has a simple form that depends on the curvature of the lowest energy diffusion path in the 3N-dimensional coordinate space. We also find that so long as the intramolecular forces are sufficiently strong, memory effects are usually not significant and the Markov approximation can be employed, resulting in a simple one-dimensional model that can account for the effect of the dynamics of the molecular vibrations on the diffusive motion.

Hemolytic disease of the fetus and newborn in the molecular era.

Science.gov (United States)

Fasano, Ross M

2016-02-01

Maternal-fetal red cell antigen incompatibility can lead to alloimmunization, maternal immunoglobulin transplacental transfer, and hemolytic disease of the fetus and newborn (HDFN). The use of routine antenatal anti-D prophylaxis (RAADP) has sharply decreased the incidence of and mortality from HDFN due to RhD allosensitization. The ability to identify pregnancies/fetuses at risk of HDFN has significantly improved due to paternal molecular RHD zygosity testing, and non-invasive fetal molecular diagnostics for detecting putative antigen(s) (notably RhD) in fetuses utilizing cff-DNA in maternal plasma. Fetal RHD genotyping using cff-DNA has become increasingly accurate for fetal RHD detection, prompting some countries to implement targeted RAADP through mass screening programs of RhD-negative pregnant women. Along with middle cerebral artery Doppler ultrasonography for predicting fetal anemia, non-invasive fetal molecular diagnostics have greatly decreased the need for invasive diagnostic procedures in pregnancies at risk for severe HDFN. This review highlights these molecular advancements in HDFN-related prenatal diagnostics. Copyright © 2015 Elsevier Ltd. All rights reserved.

Trapping molecules in two and three dimensions

International Nuclear Information System (INIS)

Pinkse, PW.H.; Junglen, T.; Rieger, T.; Rangwala, S.A.; Windpassinger, P.; Rempe, G.

2005-01-01

Full text: Cold molecules offer a new testing ground for quantum-physical effects in nature. For example, producing slow beams of large molecules could push experiments studying the boundary between quantum interference and classical particles up towards ever heavier particles. Moreover, cold molecules, in particular YbF, seem an attractive way to narrow down the constraints on the value of the electron dipole moment and finally, quantum information processing using chains of cold polar molecules or vibrational states in molecules have been proposed. All these proposals rely on advanced production and trapping techniques, most of which are still under development. Therefore, novel production and trapping techniques for cold molecules could offer new possibilities not found in previous methods. Electric traps hold promise for deep trap potentials for neutral molecules. Recently we have demonstrated two-dimensional trapping of polar molecules in a four-wire guide using electrostatic and electrodynamic trapping techniques. Filled from a thermal effusive source, such a guide will deliver a beam of slow molecules, which is an ideal source for interferometry experiments with large molecules, for instance. Here we report about the extension of this work to three-dimensional trapping. Polar molecules with a positive Stark shift can be trapped in the minimum of an electrostatic field. We have successfully tested a large volume electrostatic trap for ND3 molecules. A special feature of this trap is that it can be loaded continuously from an electrostatic guide, at a temperature of a few hundred mK. (author)

Chemical Principles and Interference in the Electrical Conductance of Single Molecules

DEFF Research Database (Denmark)

Borges, Anders Christian

, the conductance of molecules can vary orders of magnitude and the concept of interference is believed to play a major role in this. This thesis investigates the links between single molecule conductance, chemistry and interference effects in short organic molecules. It is investigated to which extent...... the conductance can be understood in terms of separate contributions and when the effects of interference are important. Links between chemical principles and constructive- and destructive interference effects are demonstrated using a combination of simple models, atomistic calculations and Scanning......-Tunneling Microscope Break-Junction experiments (STM-BJ). It is demonstrated that these links can be used to design molecules exhibiting surprising interference effects and to interpret and predict the trends in the characteristic conductance of single molecules without resorting to numerical computational methods...

Lattice diffusion of a single molecule in solution

Science.gov (United States)

Ruggeri, Francesca; Krishnan, Madhavi

2017-12-01

The ability to trap a single molecule in an electrostatic potential well in solution has opened up new possibilities for the use of molecular electrical charge to study macromolecular conformation and dynamics at the level of the single entity. Here we study the diffusion of a single macromolecule in a two-dimensional lattice of electrostatic traps in solution. We report the ability to measure both the size and effective electrical charge of a macromolecule by observing single-molecule transport trajectories, typically a few seconds in length, using fluorescence microscopy. While, as shown previously, the time spent by the molecule in a trap is a strong function of its effective charge, we demonstrate here that the average travel time between traps in the landscape yields its hydrodynamic radius. Tailoring the pitch of the lattice thus yields two different experimentally measurable time scales that together uniquely determine both the size and charge of the molecule. Since no information is required on the location of the molecule between consecutive departure and arrival events at lattice sites, the technique is ideally suited to measurements on weakly emitting entities such as single molecules.

Effects of quantum chemistry models for bound electrons on positron annihilation spectra for atoms and small molecules

International Nuclear Information System (INIS)

Wang Feng; Ma Xiaoguang; Selvam, Lalitha; Gribakin, Gleb; Surko, Clifford M

2012-01-01

The Doppler-shift spectra of the γ-rays from positron annihilation in molecules were determined by using the momentum distribution of the annihilation electron–positron pair. The effect of the positron wavefunction on spectra was analysed in a recent paper (Green et al 2012 New J. Phys. 14 035021). In this companion paper, we focus on the dominant contribution to the spectra, which arises from the momenta of the bound electrons. In particular, we use computational quantum chemistry models (Hartree–Fock with two basis sets and density functional theory (DFT)) to calculate the wavefunctions of the bound electrons. Numerical results are presented for noble gases and small molecules such as H 2 , N 2 , O 2 , CH 4 and CF 4 . The calculations reveal relatively small effects on the Doppler-shift spectra from the level of inclusion of electron correlation energy in the models. For atoms, the difference in the full-width at half-maximum of the spectra obtained using the Hartree–Fock and DFT models does not exceed 2%. For molecules the difference can be much larger, reaching 8% for some molecular orbitals. These results indicate that the predicted positron annihilation spectra for molecules are generally more sensitive to inclusion of electron correlation energies in the quantum chemistry model than the spectra for atoms are. (paper)

Amino-terminal pro-brain natriuretic peptide in children with latent rheumatic heart disease

Directory of Open Access Journals (Sweden)

Justin P Zachariah

2016-01-01

Conclusion: Serum NT-proBNP did not distinguish between latent RHD cases and the controls. Sex and within-family exposures may confound this result. More investigation into biomarker-based RHD detection is warranted.

Bond-equilibrium theory of liquid Se-Te alloys. II. Effect of singly attached ring molecules

Science.gov (United States)

Cutler, Melvin; Bez, Wolfgang G.

1981-06-01

A statistical-mechanical theory for bond equilibrium of chain polymers containing threefold (3F) and onefold (1F) bond defects is extended to include the effects of free ring molecules and ring molecules attached to chains by a single 3F atom. Positively charged singly attached rings are shown to play a key role in bond equilibrium in liquid Sex Te1-x by permitting the formation of ion pairs in which both constituents are effectively chain terminators, thus decreasing the average polymer size. The theory is applied to explain the behavior of the paramagnetic susceptibility, χp, and electronic transport as affected by the Fermi energy EF. It is found that the increase in χp with the concentration of Te is primarily the result of the smaller energy for breaking Te bonds. In addition, attached rings play an important role in determining the effect of temperature on χp. At x<~0.5, the concentrations of both free and attached rings becomes small at high T because of the high concentration of bond defects.

Rheumatic Heart Disease-Attributable Mortality at Ages 5-69 Years in Fiji: A Five-Year, National, Population-Based Record-Linkage Cohort Study.

Science.gov (United States)

Parks, Tom; Kado, Joseph; Miller, Anne E; Ward, Brenton; Heenan, Rachel; Colquhoun, Samantha M; Bärnighausen, Till W; Mirabel, Mariana; Bloom, David E; Bailey, Robin L; Tukana, Isimeli N; Steer, Andrew C

2015-01-01

Rheumatic heart disease (RHD) is considered a major public health problem in developing countries, although scarce data are available to substantiate this. Here we quantify mortality from RHD in Fiji during 2008-2012 in people aged 5-69 years. Using 1,773,999 records derived from multiple sources of routine clinical and administrative data, we used probabilistic record-linkage to define a cohort of 2,619 persons diagnosed with RHD, observed for all-cause mortality over 11,538 person-years. Using relative survival methods, we estimated there were 378 RHD-attributable deaths, almost half of which occurred before age 40 years. Using census data as the denominator, we calculated there were 9.9 deaths (95% CI 9.8-10.0) and 331 years of life-lost (YLL, 95% CI 330.4-331.5) due to RHD per 100,000 person-years, standardised to the portion of the WHO World Standard Population aged 0-69 years. Valuing life using Fiji's per-capita gross domestic product, we estimated these deaths cost United States Dollar $6,077,431 annually. Compared to vital registration data for 2011-2012, we calculated there were 1.6-times more RHD-attributable deaths than the number reported, and found our estimate of RHD mortality exceeded all but the five leading reported causes of premature death, based on collapsed underlying cause-of-death diagnoses. Rheumatic heart disease is a leading cause of premature death as well as an important economic burden in this setting. Age-standardised death rates are more than twice those reported in current global estimates. Linkage of routine data provides an efficient tool to better define the epidemiology of neglected diseases.

Rheumatic Heart Disease-Attributable Mortality at Ages 5-69 Years in Fiji: A Five-Year, National, Population-Based Record-Linkage Cohort Study.

Directory of Open Access Journals (Sweden)

Tom Parks

Full Text Available Rheumatic heart disease (RHD is considered a major public health problem in developing countries, although scarce data are available to substantiate this. Here we quantify mortality from RHD in Fiji during 2008-2012 in people aged 5-69 years.Using 1,773,999 records derived from multiple sources of routine clinical and administrative data, we used probabilistic record-linkage to define a cohort of 2,619 persons diagnosed with RHD, observed for all-cause mortality over 11,538 person-years. Using relative survival methods, we estimated there were 378 RHD-attributable deaths, almost half of which occurred before age 40 years. Using census data as the denominator, we calculated there were 9.9 deaths (95% CI 9.8-10.0 and 331 years of life-lost (YLL, 95% CI 330.4-331.5 due to RHD per 100,000 person-years, standardised to the portion of the WHO World Standard Population aged 0-69 years. Valuing life using Fiji's per-capita gross domestic product, we estimated these deaths cost United States Dollar $6,077,431 annually. Compared to vital registration data for 2011-2012, we calculated there were 1.6-times more RHD-attributable deaths than the number reported, and found our estimate of RHD mortality exceeded all but the five leading reported causes of premature death, based on collapsed underlying cause-of-death diagnoses.Rheumatic heart disease is a leading cause of premature death as well as an important economic burden in this setting. Age-standardised death rates are more than twice those reported in current global estimates. Linkage of routine data provides an efficient tool to better define the epidemiology of neglected diseases.

Live-cell microscopy reveals small molecule inhibitor effects on MAPK pathway dynamics.

Directory of Open Access Journals (Sweden)

Daniel J Anderson

Full Text Available Oncogenic mutations in the mitogen activated protein kinase (MAPK pathway are prevalent in human tumors, making this pathway a target of drug development efforts. Recently, ATP-competitive Raf inhibitors were shown to cause MAPK pathway activation via Raf kinase priming in wild-type BRaf cells and tumors, highlighting the need for a thorough understanding of signaling in the context of small molecule kinase inhibitors. Here, we present critical improvements in cell-line engineering and image analysis coupled with automated image acquisition that allow for the simultaneous identification of cellular localization of multiple MAPK pathway components (KRas, CRaf, Mek1 and Erk2. We use these assays in a systematic study of the effect of small molecule inhibitors across the MAPK cascade either as single agents or in combination. Both Raf inhibitor priming as well as the release from negative feedback induced by Mek and Erk inhibitors cause translocation of CRaf to the plasma membrane via mechanisms that are additive in pathway activation. Analysis of Erk activation and sub-cellular localization upon inhibitor treatments reveals differential inhibition and activation with the Raf inhibitors AZD628 and GDC0879 respectively. Since both single agent and combination studies of Raf and Mek inhibitors are currently in the clinic, our assays provide valuable insight into their effects on MAPK signaling in live cells.

Effective intermolecular potential and critical point for C60 molecule

Science.gov (United States)

Ramos, J. Eloy

2017-07-01

The approximate nonconformal (ANC) theory is applied to the C60 molecule. A new binary potential function is developed for C60, which has three parameters only and is obtained by averaging the site-site carbon interactions on the surface of two C60 molecules. It is shown that the C60 molecule follows, to a good approximation, the corresponding states principle with n-C8H18, n-C4F10 and n-C5F12. The critical point of C60 is estimated in two ways: first by applying the corresponding states principle under the framework of the ANC theory, and then by using previous computer simulations. The critical parameters obtained by applying the corresponding states principle, although very different from those reported in the literature, are consistent with the previous results of the ANC theory. It is shown that the Girifalco potential does not correspond to an average of the site-site carbon-carbon interaction.

Effects of microwave on spin tunneling in single-molecule magnets

Science.gov (United States)

Kim, Gwang-Hee; Kim, Tae-Suk

2005-03-01

We study theoretically the effects of the irradiated microwave on the magnetization in single-molecule magnets (SMMs) like V15 and Fe8. We find that the shape of magnetization depends on the microwave intensity as well as the microwave polarization. The applied microwave field enhances the tunneling probability. The linearly polarized microwaves induce the suppression of magnetization at both positive and negative magnetic fields. The circularly polarized microwaves are absorbed either at one direction of magnetic field or at both directions of magnetic fields, depending on the polarization directions with respect to the direction of longitudinal magnetic field. The generic features we found will be compared with the recent experimental results.

Detection of the new emerging rabbit haemorrhagic disease type 2 virus (RHDV2) in Sicily from rabbit (Oryctolagus cuniculus) and Italian hare (Lepus corsicanus).

Science.gov (United States)

Camarda, A; Pugliese, N; Cavadini, P; Circella, E; Capucci, L; Caroli, A; Legretto, M; Mallia, E; Lavazza, A

2014-12-01

Rabbit haemorrhagic disease virus (RHDV), a member of the genus Lagovirus, causes rabbit haemorrhagic disease (RHD), a fatal hepatitis of rabbits, not previously reported in hares. Recently, a new RHDV-related virus emerged, called RHDV2. This lagovirus can cause RHD in rabbits and disease and mortality in Lepus capensis (Cape hare). Here we describe a case of RHDV2 infection in another hare species, Lepus corsicanus, during a concurrent RHD outbreak in a group of wild rabbits. The same RHDV2 strain infected rabbits and a hare, also causing a RHD-like syndrome in the latter. Our findings confirmed the capability of RHDV2 to infect hosts other than rabbits and improve the knowledge about the epidemiology and the host range of this new lagovirus. Copyright © 2014 Elsevier Ltd. All rights reserved.

Surface diffusion of long chainlike molecules: The role of memory effects and stiffness on effective diffusion barriers

DEFF Research Database (Denmark)

Hjelt, T.; Vattulainen, Ilpo Tapio

2000-01-01

stiffness. Our primary aim is to consider the role played by chain stiffness and the resulting memory effects in tracer diffusion, and in particular their role in the effective tracer diffusion barrier E-A(T) extracted from the well-known Arrhenius form. We show that the memory effects in tracer diffusion......, for a single diffusing chain, about 20% of E-A(T) arises from temperature variations in the memory effects, while only the remaining part comes from thermally activated chain segment movements. At a finite coverage, the memory contribution in E-A(T) is even larger and is typically about 20%-40%. Further...... of recent experimental work as regards surface diffusion of long DNA molecules on a biological interface. (C) 2000 American Institute of Physics....

Small molecules make big differences: molecular doping effects on electronic and optical properties of phosphorene

International Nuclear Information System (INIS)

Jing, Yu; Tang, Qing; He, Peng; Zhou, Zhen; Shen, Panwen

2015-01-01

Systematical computations on the density functional theory were performed to investigate the adsorption of three typical organic molecules, tetracyanoquinodimethane (TCNQ), tetracyanoethylene (TCNE) and tetrathiafulvalene (TTF), on the surface of phosphorene monolayers and thicker layers. There exist considerable charge transfer and strong non-covalent interaction between these molecules and phosphorene. In particular, the band gap of phosphorene decreases dramatically due to the molecular modification and can be further tuned by applying an external electric field. Meanwhile, surface molecular modification has proven to be an effective way to enhance the light harvesting of phosphorene in different directions. Our results predict a flexible method toward modulating the electronic and optical properties of phosphorene and shed light on its experimental applications. (paper)

Interference, confinement and non Franck-Condon effects in photoionization of H{sub 2} molecules at high photon energy

Energy Technology Data Exchange (ETDEWEB)

Fernandez, J; MartIn, F [Departamento de Quimica, C-9, Universidad Autonoma de Madrid, 28049 Madrid (Spain); Fojon, O, E-mail: jorge@phys.au.d, E-mail: ofojon@fceia.unr.edu.a, E-mail: fernando.martin@uam.e [Institute de Fisica Rosario (CONICET-UNR), Pellegrini 250, 2000 Rosario (Argentina)

2009-11-01

We study in detail photoionization of H{sub 2} molecules by high energy photons. Bound and continuum states are accurately evaluated by using B-spline basis functions. The usual Franck-Condon behavior is not followed when the molecule is parallel to the polarization direction. The origin of this anomaly is related to interference effects. Moreover, it is shown that at these high photon energies, the nuclear asymmetry parameter exhibits a reminiscence of these interference patterns.

Atkins' molecules

CERN Document Server

Atkins, Peters

2003-01-01

Originally published in 2003, this is the second edition of a title that was called 'the most beautiful chemistry book ever written'. In it, we see the molecules responsible for the experiences of our everyday life - including fabrics, drugs, plastics, explosives, detergents, fragrances, tastes, and sex. With engaging prose Peter Atkins gives a non-technical account of an incredible range of aspects of the world around us, showing unexpected connections, and giving an insight into how this amazing world can be understood in terms of the atoms and molecules from which it is built. The second edition includes dozens of extra molecules, graphical presentation, and an even more accessible and enthralling account of the molecules themselves.

Plasma-neutral gas interaction in a tokamak divertor: effects of hydrogen molecules and plasma recombination

International Nuclear Information System (INIS)

Krasheninnikov, S.I.; Pigarov, A.Yu.; Soboleva, T.K.; Sigmar, D.J.

1997-01-01

We investigate the influence of hydrogen molecules on plasma recombination using a collisional-radiative model for multispecies hydrogen plasmas and tokamak detached divertor parameters. The rate constant found for molecular activated recombination of a plasma can be as high as 2 x 10 -10 cm 3 /s, confirming our pervious estimates. We investigate the effects of hydrogen molecules and plasma recombination on self-consistent plasma-neutral gas interactions in the recycling region of a tokamak divertor. We treat the plasma flow in a fluid approximation retaining the effects of plasma recombination and employing a Knudsen neutral transport model for a 'gas box' divertor geometry. For the model of plasma-neutral interactions we employ we find: (a) molecular activated recombination is a dominant channel of divertor plasma recombination; and (b) plasma recombination is a key element leading to a decrease in the plasma flux onto the target and substantial plasma pressure drop which are the main features of detached divertor regimes. (orig.)

Thermal ion-molecule reactions in oxygen-containing molecules

International Nuclear Information System (INIS)

Kumakura, Minoru

1981-02-01

The energetics of ions and the thermal ion-molecule reactions in oxygen-containing molecules have been studied with a modified time-of-flight mass spectrometer. It was found that the translational energy of ion can be easily obtained from analysis of the decay curve using the time-of-flight mass spectrometer. The condensation-elimination reactions proceeded via cross- and homo-elimination mechanism in which the nature of intermediate-complex could be correlated with the nature of reactant ion. It was elucidated that behavior of poly-atomic oxygen-containing ions on the condensation-elimination reactions is considerably influenced by their oxonium ion structures having functional groups. In addition, the rate constants of the condensation-elimination reactions have affected with the energy state of reactant ion and the dipole moment and/or the polarizability of neutral molecule. It was clarified that the rate constants of the ion-molecule clustering reactions in poly-atomic oxygen-containing molecules such as cyclic ether of six member rings are very large and the cluster ions are stable owing to the large number of vibrational degree of freedom in the cluster ions. (author)

Cold Rydberg molecules

Science.gov (United States)

Raithel, Georg; Zhao, Jianming

2017-04-01

Cold atomic systems have opened new frontiers at the interface of atomic and molecular physics. These include research on novel types of Rydberg molecules. Three types of molecules will be reviewed. Long-range, homonuclear Rydberg molecules, first predicted in [1] and observed in [2], are formed via low-energy electron scattering of the Rydberg electron from a ground-state atom within the Rydberg atom's volume. The binding mostly arises from S- and P-wave triplet scattering. We use a Fermi model that includes S-wave and P-wave singlet and triplet scattering, the fine structure coupling of the Rydberg atom and the hyperfine structure coupling of the 5S1/2 atom (in rubidium [3]). The hyperfine structure gives rise to mixed singlet-triplet potentials for both low-L and high-L Rydberg molecules [3]. A classification into Hund's cases [3, 4, 5] will be discussed. The talk further includes results on adiabatic potentials and adiabatic states of Rydberg-Rydberg molecules in Rb and Cs. These molecules, which have even larger bonding length than Rydberg-ground molecules, are formed via electrostatic multipole interactions. The leading interaction term of neutral Rydberg-Rydberg molecules is between two dipoles, while for ionic Rydberg molecules it is between a dipole and a monopole. NSF (PHY-1506093), NNSF of China (61475123).

Effects of Water Molecule on CO Oxidation by OH: Reaction Pathways, Kinetic Barriers, and Rate Constants.

Science.gov (United States)

Zhang, Linyao; Yang, Li; Zhao, Yijun; Zhang, Jiaxu; Feng, Dongdong; Sun, Shaozeng

2017-07-06

The water dilute oxy-fuel combustion is a clean combustion technology for near-zero emission power; and the presence of water molecule could have both kinetic and dynamic effects on combustion reactions. The reaction OH + CO → CO 2 + H, one of the most important elementary reactions, has been investigated by extensive electronic structure calculations. And the effects of a single water molecule on CO oxidation have been studied by considering the preformed OH(H 2 O) complex reacts with CO. The results show little change in the reaction pathways, but the additional water molecule actually increases the vibrationally adiabatic energy barriers (V a G ). Further thermal rate constant calculations in the temperature range of 200 to 2000 K demonstrate that the total low-pressure limit rate constant for the water assisted OH(H 2 O) + CO → CO 2 + H 2 O + H reaction is 1-2 orders lower than that of the water unassisted one, which is consistent with the change of V a G . Therefore, the hydrated radical OH(H 2 O) would actually slow down the oxidation of CO. Meanwhile, comparisons show that the M06-2X/aug-cc-pVDZ method gives a much better estimation in energy and thus is recommended to be employed for direct dynamics simulations.

Consistent quantum approach to new laser-electron-nuclear effects in diatomic molecules

International Nuclear Information System (INIS)

Glushkov, A V; Malinovskaya, S V; Loboda, A V; Shpinareva, I M; Prepelitsa, G P

2006-01-01

We present a consistent, quantum approach to the calculation of electron-nuclear γ. spectra (set of vibrational and rotational satellites) for nuclei in diatomic molecules. The approach generelizes the well known Letokhov-Minogin model and is based on the Dunham model potential approximation for potential curves of diatomic molecules. The method is applied to the calculation of probabilities of the vibration-rotation-nuclear transitions in a case of emission and absorption spectrum for the nucleus 127 I (E γ (0) = 203 keV) linked with the molecule H 127 I

Photoexcitation circular dichroism in chiral molecules

Science.gov (United States)

Beaulieu, S.; Comby, A.; Descamps, D.; Fabre, B.; Garcia, G. A.; Géneaux, R.; Harvey, A. G.; Légaré, F.; Mašín, Z.; Nahon, L.; Ordonez, A. F.; Petit, S.; Pons, B.; Mairesse, Y.; Smirnova, O.; Blanchet, V.

2018-05-01

Chiral effects appear in a wide variety of natural phenomena and are of fundamental importance in science, from particle physics to metamaterials. The standard technique of chiral discrimination—photoabsorption circular dichroism—relies on the magnetic properties of a chiral medium and yields an extremely weak chiral response. Here, we propose and demonstrate an orders of magnitude more sensitive type of circular dichroism in neutral molecules: photoexcitation circular dichroism. This technique does not rely on weak magnetic effects, but takes advantage of the coherent helical motion of bound electrons excited by ultrashort circularly polarized light. It results in an ultrafast chiral response and the efficient excitation of a macroscopic chiral density in an initially isotropic ensemble of randomly oriented chiral molecules. We probe this excitation using linearly polarized laser pulses, without the aid of further chiral interactions. Our time-resolved study of vibronic chiral dynamics opens a way to the efficient initiation, control and monitoring of chiral chemical change in neutral molecules at the level of electrons.

Copy-Number Disorders Are a Common Cause of Congenital Kidney Malformations

OpenAIRE

Sanna-Cherchi, Simone; Kiryluk, Krzysztof; Burgess, Katelyn E.; Bodria, Monica; Sampson, Matthew G.; Hadley, Dexter; Nees, Shannon N.; Verbitsky, Miguel; Perry, Brittany J.; Sterken, Roel; Lozanovski, Vladimir J.; Materna-Kiryluk, Anna; Barlassina, Cristina; Kini, Akshata; Corbani, Valentina

2012-01-01

We examined the burden of large, rare, copy-number variants (CNVs) in 192 individuals with renal hypodysplasia (RHD) and replicated findings in 330 RHD cases from two independent cohorts. CNV distribution was significantly skewed toward larger gene-disrupting events in RHD cases compared to 4,733 ethnicity-matched controls (p = 4.8 × 10−11). This excess was attributable to known and novel (i.e., not present in any database or in the literature) genomic disorders. All together, 55/522 (10.5%) ...

Novel bivalent vectored vaccine for control of myxomatosis and rabbit haemorrhagic disease.

Science.gov (United States)

Spibey, N; McCabe, V J; Greenwood, N M; Jack, S C; Sutton, D; van der Waart, L

2012-03-24

A novel, recombinant myxoma virus-rabbit haemorrhagic disease virus (RHDV) vaccine has been developed for the prevention of myxomatosis and rabbit haemorrhagic disease (RHD). A number of laboratory studies are described illustrating the safety and efficacy of the vaccine following subcutaneous administration in laboratory rabbits from four weeks of age onwards. In these studies, both vaccinated and unvaccinated control rabbits were challenged using pathogenic strains of RHD and myxoma viruses, and 100 per cent of the vaccinated rabbits were protected against both myxomatosis and RHD.

Entanglement of polar symmetric top molecules as candidate qubits.

Science.gov (United States)

Wei, Qi; Kais, Sabre; Friedrich, Bretislav; Herschbach, Dudley

2011-10-21

Proposals for quantum computing using rotational states of polar molecules as qubits have previously considered only diatomic molecules. For these the Stark effect is second-order, so a sizable external electric field is required to produce the requisite dipole moments in the laboratory frame. Here we consider use of polar symmetric top molecules. These offer advantages resulting from a first-order Stark effect, which renders the effective dipole moments nearly independent of the field strength. That permits use of much lower external field strengths for addressing sites. Moreover, for a particular choice of qubits, the electric dipole interactions become isomorphous with NMR systems for which many techniques enhancing logic gate operations have been developed. Also inviting is the wider chemical scope, since many symmetric top organic molecules provide options for auxiliary storage qubits in spin and hyperfine structure or in internal rotation states. © 2011 American Institute of Physics

Coherent Bichromatic Force Deflection of Molecules

Science.gov (United States)

Kozyryev, Ivan; Baum, Louis; Aldridge, Leland; Yu, Phelan; Eyler, Edward E.; Doyle, John M.

2018-02-01

We demonstrate the effect of the coherent optical bichromatic force on a molecule, the polar free radical strontium monohydroxide (SrOH). A dual-frequency retroreflected laser beam addressing the X˜2Σ+↔A˜2Π1 /2 electronic transition coherently imparts momentum onto a cryogenic beam of SrOH. This directional photon exchange creates a bichromatic force that transversely deflects the molecules. By adjusting the relative phase between the forward and counterpropagating laser beams we reverse the direction of the applied force. A momentum transfer of 70 ℏk is achieved with minimal loss of molecules to dark states. Modeling of the bichromatic force is performed via direct numerical solution of the time-dependent density matrix and is compared with experimental observations. Our results open the door to further coherent manipulation of molecular motion, including the efficient optical deceleration of diatomic and polyatomic molecules with complex level structures.

The Effects of Perchlorate and its Precursors on Organic Molecules under Simulated Mars Conditions

Science.gov (United States)

Carrier, B. L.; Beegle, L. W.; Bhartia, R.; Abbey, W. J.

2016-12-01

Perchlorate (ClO4-) was first detected on Mars by the Phoenix Lander in 2008 [1] and has subsequently been detected by Curiosity in Gale Crater [2], in Mars meteorite EETA79001 [3], and has been proposed as a possible explanation for results obtained by Viking [4]. Perchlorate has also been shown to be formed under current Mars conditions via the oxidation of mineral chlorides, further supporting the theory that perchlorate is present globally on Mars [5]. The discovery of perchlorate on Mars has raised important questions about its effects on the survival and detection of organic molecules. Although it has been shown that pyrolysis in the presence of perchlorate results in the alteration or destruction of organic molecules [2, 4], few studies have been conducted on the potential effects of perchlorate and its precursors on organic molecules prior to analysis. Perchlorate is typically inert under Mars temperatures and pressures, but it has been shown to decompose to form reactive oxychlorine species such as chlorite (ClO2-), hypochlorite (ClO-) and chlorine dioxide (ClO2) when exposed to Mars conditions including ionizing radiation [6]. The oxidation of chloride to perchlorate also results in the formation of reactive oxychlorine species such as chlorate (ClO3-) [5]. Here we investigate the effects of perchlorate and its oxychlorine precursors on organic molecules. Experiments are performed in a Mars Simulation Chamber (MSC) capable of reproducing the temperature, pressure, atmospheric composition and UV flux found on Mars. Soil simulants are prepared consisting of Mojave Mars Simulant (MMS) [7] and each organic, as well as varying concentrations of perchlorate and/or chloride salts, and exposed in the MSC. Subsequent to exposure in the MSC samples are leached and the leachate analyzed by HPLC and LC-MS to determine the degree of degradation of the original organic and the identity of any potential decomposition products formed by oxidation or chlorination

Perturbed path integrals in imaginary time: Efficiently modeling nuclear quantum effects in molecules and materials

Science.gov (United States)

Poltavsky, Igor; DiStasio, Robert A.; Tkatchenko, Alexandre

2018-03-01

Nuclear quantum effects (NQE), which include both zero-point motion and tunneling, exhibit quite an impressive range of influence over the equilibrium and dynamical properties of molecules and materials. In this work, we extend our recently proposed perturbed path-integral (PPI) approach for modeling NQE in molecular systems [I. Poltavsky and A. Tkatchenko, Chem. Sci. 7, 1368 (2016)], which successfully combines the advantages of thermodynamic perturbation theory with path-integral molecular dynamics (PIMD), in a number of important directions. First, we demonstrate the accuracy, performance, and general applicability of the PPI approach to both molecules and extended (condensed-phase) materials. Second, we derive a series of estimators within the PPI approach to enable calculations of structural properties such as radial distribution functions (RDFs) that exhibit rapid convergence with respect to the number of beads in the PIMD simulation. Finally, we introduce an effective nuclear temperature formalism within the framework of the PPI approach and demonstrate that such effective temperatures can be an extremely useful tool in quantitatively estimating the "quantumness" associated with different degrees of freedom in the system as well as providing a reliable quantitative assessment of the convergence of PIMD simulations. Since the PPI approach only requires the use of standard second-order imaginary-time PIMD simulations, these developments enable one to include a treatment of NQE in equilibrium thermodynamic properties (such as energies, heat capacities, and RDFs) with the accuracy of higher-order methods but at a fraction of the computational cost, thereby enabling first-principles modeling that simultaneously accounts for the quantum mechanical nature of both electrons and nuclei in large-scale molecules and materials.

Electron-vibron coupling effects on electron transport via a single-molecule magnet

NARCIS (Netherlands)

McCaskey, A.; Yamamoto, Y.; Warnock, M.; Burzuri, E.; Van der Zant, H.S.J.; Park, K.

2015-01-01

We investigate how the electron-vibron coupling influences electron transport via an anisotropic magnetic molecule, such as a single-molecule magnet (SMM) Fe4, by using a model Hamiltonian with parameter values obtained from density-functional theory (DFT). The magnetic anisotropy parameters,

Lack of a synergistic effect of a non-viral ALS gene therapy based on BDNF and a TTC fusion molecule

Directory of Open Access Journals (Sweden)

Navarro Xavier

2011-03-01

Full Text Available Abstract Background Amyotrophic lateral sclerosis (ALS is one of the most devastating neurodegenerative diseases. Neurotrophic factors have been widely tested to counteract neurodegenerative conditions, despite their unspecific neuronal access. The non-toxic C-terminal fragment of the tetanus toxin (TTC heavy chain has been studied not only as a carrier molecule to the CNS but also as a neuroprotective agent. Because the neurotrophic effects of BDNF have been demonstrated in vitro and in vivo, the question addressed in this work is whether a fusion molecule of BDNF-TTC may have a synergistic effect and enhance the neuroprotective properties of TTC alone in a mouse model of ALS. Methods Recombinant plasmid constructs (pCMV-TTC and pCMV-BDNF-TTC were injected into the quadriceps femoris and triceps brachialis muscles of SOD1G93A transgenic mice at 8 weeks of age. The hanging wire and rotarod tests were performed to assess motor coordination, strength and balance. Electrophysiological tests, morphological assays of spinal cord sections of L2 and L4 segments, and gene and protein expression analyses were performed. The Kaplan-Meier survival analysis test was used for comparisons of survival. Multiple comparisons of data were analyzed using a one-way analysis of variance (ANOVA. Results Treatment with the fusion-molecule BDNF-TTC and with TTC alone significantly delayed the onset of symptoms and functional deficits of SOD1G93A mice. Muscle innervation was partially preserved with these treatments, and the number of surviving motoneurons in L2 spinal cord segment was increased particularly by the fusion protein induction. Inhibition of pro-apoptotic protein targets (caspase-3 and Bax and significant phosphorylation of Akt and ERK were also found in the spinal cord of treated mice. Conclusions Significant improvements in behavioral and electrophysiological results, motoneuron survival and anti-apoptotic/survival-activated pathways were observed with

Rheumatic Heart Disease-Attributable Mortality at Ages 5–69 Years in Fiji: A Five-Year, National, Population-Based Record-Linkage Cohort Study

Science.gov (United States)

Parks, Tom; Kado, Joseph; Miller, Anne E.; Ward, Brenton; Heenan, Rachel; Colquhoun, Samantha M.; Bärnighausen, Till W.; Mirabel, Mariana; Bloom, David E.; Bailey, Robin L.; Tukana, Isimeli N.; Steer, Andrew C.

2015-01-01

Background Rheumatic heart disease (RHD) is considered a major public health problem in developing countries, although scarce data are available to substantiate this. Here we quantify mortality from RHD in Fiji during 2008–2012 in people aged 5–69 years. Methods and Findings Using 1,773,999 records derived from multiple sources of routine clinical and administrative data, we used probabilistic record-linkage to define a cohort of 2,619 persons diagnosed with RHD, observed for all-cause mortality over 11,538 person-years. Using relative survival methods, we estimated there were 378 RHD-attributable deaths, almost half of which occurred before age 40 years. Using census data as the denominator, we calculated there were 9.9 deaths (95% CI 9.8–10.0) and 331 years of life-lost (YLL, 95% CI 330.4–331.5) due to RHD per 100,000 person-years, standardised to the portion of the WHO World Standard Population aged 0–69 years. Valuing life using Fiji’s per-capita gross domestic product, we estimated these deaths cost United States Dollar $6,077,431 annually. Compared to vital registration data for 2011–2012, we calculated there were 1.6-times more RHD-attributable deaths than the number reported, and found our estimate of RHD mortality exceeded all but the five leading reported causes of premature death, based on collapsed underlying cause-of-death diagnoses. Conclusions Rheumatic heart disease is a leading cause of premature death as well as an important economic burden in this setting. Age-standardised death rates are more than twice those reported in current global estimates. Linkage of routine data provides an efficient tool to better define the epidemiology of neglected diseases. PMID:26371755

A Review of Acute Rheumatic Fever and Rheumatic Heart Disease Research in Malaysia.

Science.gov (United States)

Hung, L C; Nadia, R

2016-06-01

A total of 39 titles related to rheumatic fever or rheumatic heart disease in Malaysia were found with online literature search dating back to their inceptions and through 2014. Additional publications from conference journals were included. Nine papers were selected based on clinical relevance and future research implications. There were no population-based studies on the incidence or prevalence of ARF or RHD. In the 1980s, the incidence of admission due to ARF ranged from 2 to 21.1 per 100 000 paediatric admission per year. The burden of disease was significant in the adult population; 74.5% of patients with RHD were female, of which 77.1% were in the reproductive age group of 15-45 years old. Rheumatic mitral valve disease constituted almost half (46.7%) of all mitral valve repairs, ranging from 44.8 - 55.8 patients per year from 1997 - 2003. From 2010-2012, mitral valve interventions increased to 184 per year, of which 85.7% were mitral valve repair. In children with ARF, 25.4% - 41.7% had past history of rheumatic fever or RHD. In patients with rheumatic mitral valve disease undergoing surgical or medical interventions, only 6% reported history of ARF, none had history of GABHS pharyngitis or antibiotic prophylaxis. Only 44.7% of patients with RHD on follow-up were on intramuscular benzathine penicillin prophylaxis. Overall, there is scarcity of publications on ARF and RHD in Malaysia. Priority areas for research include determination of the incidence and prevalence of ARF and RHD, identification of high-risk populations, evaluation on the implementation and adherence of secondary preventive measures, identification of subclinical RHD especially amongst the high-risk population, and a surveillance system to monitor and evaluate preventive measures, disease progression and outcomes.

Undetected rheumatic heart disease revealed using portable echocardiography in a population of school students in Tairawhiti, New Zealand.

Science.gov (United States)

Cramp, Geoffrey; Stonehouse, Mary; Webb, Rachel; Webb, Rachel; Chaffey-Aupouri, Gina; Wilson, Nigel

2012-10-12

The aim of this programme was to find undetected rheumatic heart disease (RHD) in students from selected schools in the Tairawhiti region (eastern part of the North Island) of New Zealand. Portable echocardiography was used to scan students in 5 urban and rural schools in Tairawhiti where the population is predominantly Maori. The age range of students in the urban schools was 10-13 years and in the rural schools 5-17 years. Those with abnormal echocardiograms were referred for a paediatric consultation, with hospital-based echocardiography if required for the clarification of diagnoses and further management. A total of 685 students, representing over 95% of the schools' students, consented to having echocardiographic scanning. After repeat hospital based echocardiography for 11 students, a total of 52 scans were regarded as abnormal. In this population definite (n=4) or probable (n=7) RHD was found in 11 students a prevalence of 1.61% (95%CIs 0.80-2.85). Possible RHD was found in 19 students. Previously undetected confirmed (n=1) or probable (n=7) RHD was found in 8 students a prevalence of 1.17% (95%CIs 0.51-2.29). Congenital heart defects (CHD) were found in 22 students a prevalence of 3.21% (95%CIs 2.02-4.83). Echocardiography was a popular modality and detected a significant burden of previously unknown RHD in this young Maori population who are now receiving penicillin. However, echocardiography detected a greater prevalence of possible RHD for which optimum management is at present uncertain. Echocardiography also detected students with a range of severity of CHD. Screening with echocardiography for RHD would involve a significant use of public health, paediatric and cardiac resources with 7.6% of students and their families requiring clinical consultations and ongoing management of the abnormal echocardiographic results.

Diatomic Molecules Effective Potential for an Harmonic Oscillator ...

African Journals Online (AJOL)

A model anharmonic potential was considered and was used in the Schrödinger time independent wave equation to describe a carbon monoxide molecule. Central difference scheme was used in approximating the derivative term in the Schrödinger equation leading to a tri-diagonal band system of equation. The method of ...

A TWO-MOMENT RADIATION HYDRODYNAMICS MODULE IN ATHENA USING A TIME-EXPLICIT GODUNOV METHOD

Energy Technology Data Exchange (ETDEWEB)

Skinner, M. Aaron; Ostriker, Eve C., E-mail: askinner@astro.umd.edu, E-mail: eco@astro.princeton.edu [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States)

2013-06-01

We describe a module for the Athena code that solves the gray equations of radiation hydrodynamics (RHD), based on the first two moments of the radiative transfer equation. We use a combination of explicit Godunov methods to advance the gas and radiation variables including the non-stiff source terms, and a local implicit method to integrate the stiff source terms. We adopt the M{sub 1} closure relation and include all leading source terms to O({beta}{tau}). We employ the reduced speed of light approximation (RSLA) with subcycling of the radiation variables in order to reduce computational costs. Our code is dimensionally unsplit in one, two, and three space dimensions and is parallelized using MPI. The streaming and diffusion limits are well described by the M{sub 1} closure model, and our implementation shows excellent behavior for a problem with a concentrated radiation source containing both regimes simultaneously. Our operator-split method is ideally suited for problems with a slowly varying radiation field and dynamical gas flows, in which the effect of the RSLA is minimal. We present an analysis of the dispersion relation of RHD linear waves highlighting the conditions of applicability for the RSLA. To demonstrate the accuracy of our method, we utilize a suite of radiation and RHD tests covering a broad range of regimes, including RHD waves, shocks, and equilibria, which show second-order convergence in most cases. As an application, we investigate radiation-driven ejection of a dusty, optically thick shell in the ISM. Finally, we compare the timing of our method with other well-known iterative schemes for the RHD equations. Our code implementation, Hyperion, is suitable for a wide variety of astrophysical applications and will be made freely available on the Web.

Prophylactic penicillin by the full moon: a novel approach in Central Australia that may help to reduce the risk of rheumatic heart disease.

Science.gov (United States)

Kearns, T M; Schultz, R; McDonald, V; Andrews, R M

2010-01-01

Uptake of penicillin prophylaxis to prevent recurrent rheumatic fever and its sequela rheumatic heart disease (RHD) is not optimal in the Northern Territory of Australia. The Full Moon Strategy (the Strategy) was introduced in the Central Australian region in June 2006 to improve the uptake of prophylactic penicillin: clients and healthcare workers were encouraged to use the full moon as a cue for the timing of the 4 weekly prophylactic penicillin injection. To determine the impact and effectiveness of the Strategy on knowledge and uptake of benzathine penicillin prophylaxis for clients at risk of RHD, and for primary healthcare workers in Central Australia. Clients at risk of RHD in four remote Aboriginal communities and the town camps of Alice Springs were identified from the RHD database. Consenting clients or their carers were interviewed about their knowledge of the Strategy and the health promotional tools used. Their healthcare records were then reviewed for prophylaxis uptake 2 years prior to and 2 years following the introduction of the Strategy. Primary healthcare workers in the four remote communities who were available at the time of the study visit were interviewed about their knowledge and use of the Strategy and the health promotional tools. Fifty RHD clients and 19 healthcare workers were interviewed. Most were aware of the flipchart but less than half knew of the calendar poster, hand-held card or radio advertisement. Prophylaxis uptake increased significantly from 47% in the 2 years prior to the introduction of the Strategy, to 57% 2 years after the Strategy was introduced. Introduction of the Strategy coincided with an improvement in uptake of prophylaxis but not around the time of the full moon. Uptake of benzathine penicillin remains inadequate and further innovative measures are needed to control rheumatic fever and its sequela in Aboriginal and Torres Strait Islander people.

Frequency of different valvular lesions of rheumatic heart disease presenting to a tertiary care hospital

International Nuclear Information System (INIS)

Rehman, J.U.; Shah, I.

2015-01-01

Rheumatic Hearth Disease (RHD) is still prevalent in our country and a great source of morbidity. This study was done with an objective to determine relative frequency of different valvular lesions of RHD presenting in a tertiary care hospital. Methods: This cross sectional study was conducted at the Cardiology Department of Hayatabad Medical Complex, Peshawar. A total of 171 cases of RHD were included through consecutive sampling technique. Results: There were 64.33% females. Mean age was 25.6 ± 6.95 years ranging from 15 to 40 years. The different percentage of valvular lesions in RHD were MR (59.06%), MS (46.78%), AR (43.85%) and mixed lesions (38.59%). Conclusion: Rheumatic heart disease is a very common disease in our community and mitral regurgitation is a predominant lesion at presentation. Females are usually affected more than males. (author)

Congenital heart disease and rheumatic heart disease in Africa: recent advances and current priorities.

Science.gov (United States)

Zühlke, Liesl; Mirabel, Mariana; Marijon, Eloi

2013-11-01

Africa has one of the highest prevalence of heart diseases in children and young adults, including congenital heart disease (CHD) and rheumatic heart disease (RHD). We present here an extensive review of recent data from the African continent highlighting key studies and information regarding progress in CHD and RHD since 2005. Main findings include evidence that the CHD burden is underestimated mainly due to the poor outcome of African children with CHD. The interest in primary prevention for RHD has been recently re-emphasised, and new data are available regarding echocardiographic screening for subclinical RHD and initiation of secondary prevention. There is an urgent need for comprehensive service frameworks to improve access and level of care and services for patients, educational programmes to reinforce the importance of prevention and early diagnosis and a relevant research agenda focusing on the African context.

Influence of the effective mass of water molecule on thermal neutron scattering; Uticaj efektivne mase molekula vode na rasejanje termalnih neutrona

Energy Technology Data Exchange (ETDEWEB)

Markovic, M [Belgrade Univ. (Yugoslavia). Elektrotehnicki Fakultet

1981-07-01

The influence of the effective water molecule mass on the thermal neutron scattering on the nucleus of the hydrogen atom has been investigated. Besides the actual water molecule mass (M = 18) the investigations have been carried out with its two effective values (M1 = 16 and M2 = 20). The differential and total cross sections have been calculated for the incident thermal neutron energy E{sub o} = 1 eV. Investigation results show different prominence of the quantum effects and for M2 the appearance of peaks in the quasielastic scattering. (author)

Motion of Br2 molecules in clathrate cages. A computational study of the dynamic effects on its spectroscopic behavior.

Science.gov (United States)

Bernal-Uruchurtu, M I; Janda, Kenneth C; Hernández-Lamoneda, R

2015-01-22

This work looks into the spectroscopic behavior of bromine molecules trapped in clathrate cages combining different methodologies. We developed a semiempirical quantum mechanical model to incorporate through molecular dynamics trajectories, the effect movement of bromine molecules in clathrate cages has on its absorption spectra. A simple electrostatic model simulating the cage environment around bromine predicts a blue shift in the spectra, in good agreement with the experimental evidence.

Intersystem crossing in complex molecules

International Nuclear Information System (INIS)

Pappalardo, R.G.

1980-01-01

The general question of singlet-triplet intersystem crossing is addressed in the context of large organic molecules, i.e., ''complex'' molecules capable of self-relaxation in the absence of collisions. Examples of spectral properties of such molecules in the vapor phase are discussed, relying on extensive Russian literature in this area. Formal expressions for the relaxation rate in the electronic excited states are derived on the basis of the formalism of collision theory, and are applied to the specific case of intersystem crossing. The derivation of the ''energy-gap'' law for triplet-singlet conversion in aromatic hydrocarbons is briefly outlined. The steep rise of internal conversion rates as a function of excess excitation energy, and its competition with the intersystem crossing process, are reviewed for the case of naphthalene vapor. A general expression for the spin-orbit interaction Hamiltonian in molecular systems is outlined. Experimental observations on singlet-triplet conversion rates and the factors that can drastically affect such rates are discussed, with emphasis on the ''in- ternal'' and ''external'' heavy-atom effects. Basic relations of ESR spectroscopy and magnetophotoselection are reviewed. Technological implications of the singlet-triplet crossing in complex molecules are discussed in the context of chelate lasers, dye lasers and luminescent displays. Effects related to singlet-triplet crossing, and generally to excited-state energy-transfer in biological systems, are exemplified by the role of aromatic amino-acids in the phosphorescence of proteins, by some recent studies of energy-transfer in models of biomembranes, and by the clustering of triplet-energy donor-acceptor pairs in micelles

Nonequilibrium Chemical Effects in Single-Molecule SERS Revealed by Ab Initio Molecular Dynamics Simulations

Energy Technology Data Exchange (ETDEWEB)

Fischer, Sean A.; Apra, Edoardo; Govind, Niranjan; Hess, Wayne P.; El-Khoury, Patrick Z.

2017-02-03

Recent developments in nanophotonics have paved the way for achieving significant advances in the realm of single molecule chemical detection, imaging, and dynamics. In particular, surface-enhanced Raman scattering (SERS) is a powerful analytical technique that is now routinely used to identify the chemical identity of single molecules. Understanding how nanoscale physical and chemical processes affect single molecule SERS spectra and selection rules is a challenging task, and is still actively debated. Herein, we explore underappreciated chemical phenomena in ultrasensitive SERS. We observe a fluctuating excited electronic state manifold, governed by the conformational dynamics of a molecule (4,4’-dimercaptostilbene, DMS) interacting with a metallic cluster (Ag20). This affects our simulated single molecule SERS spectra; the time trajectories of a molecule interacting with its unique local environment dictates the relative intensities of the observable Raman-active vibrational states. Ab initio molecular dynamics of a model Ag20-DMS system are used to illustrate both concepts in light of recent experimental results.

Bianthrone in a Single-Molecule Junction: Conductance Switching with a Bistable Molecule Facilitated by Image Charge Effects

DEFF Research Database (Denmark)

Bjørnholm, Thomas

2010-01-01

Bianthrone is a sterically hindered compound that exists in the form of two nonplanar isomers. Our experimental study of single-molecule junctions with bianthrone reveals persistent switching of electric conductance at low temperatures, which can be reasonably associated with molecular isomerizat...

Ultra-cold molecule production

International Nuclear Information System (INIS)

Ramirez-Serrano, Jamie; Chandler, David W.; Strecker, Kevin; Rahn, Larry A.

2005-01-01

The production of Ultra-cold molecules is a goal of many laboratories through out the world. Here we are pursuing a unique technique that utilizes the kinematics of atomic and molecular collisions to achieve the goal of producing substantial numbers of sub Kelvin molecules confined in a trap. Here a trap is defined as an apparatus that spatially localizes, in a known location in the laboratory, a sample of molecules whose temperature is below one degree absolute Kelvin. Further, the storage time for the molecules must be sufficient to measure and possibly further cool the molecules. We utilize a technique unique to Sandia to form cold molecules from near mass degenerate collisions between atoms and molecules. This report describes the progress we have made using this novel technique and the further progress towards trapping molecules we have cooled

Effective electronic-only Kohn–Sham equations for the muonic molecules

Science.gov (United States)

Rayka, Milad; Goli, Mohammad; Shahbazian, Shant

A set of effective electronic-only Kohn-Sham (EKS) equations are derived for the muonic molecules (containing a positively charged muon), which are completely equivalent to the coupled electronic-muonic Kohn-Sham equations derived previously within the framework of the Nuclear-Electronic Orbital density functional theory (NEO-DFT). The EKS equations contain effective non-coulombic external potentials depending on parameters describing muon vibration, which are optimized during the solution of the EKS equations making muon KS orbital reproducible. It is demonstrated that the EKS equations are derivable from a certain class of effective electronic Hamiltonians through applying the usual Hohenberg-Kohn theorems revealing a duality between the NEO-DFT and the effective electronic-only DFT methodologies. The EKS equations are computationally applied to a small set of muoniated organic radicals and it is demonstrated that a mean effective potential maybe derived for this class of muonic species while an electronic basis set is also designed for the muon. These computational ingredients are then applied to muoniated ferrocenyl radicals, which had been previously detected experimentally through adding muonium atom to ferrocene. In line with previous computational studies, from the six possible species the staggered conformer, where the muon is attached to the exo position of the cyclopentadienyl ring, is deduced to be the most stable ferrocenyl radical.

Effective electronic-only Kohn-Sham equations for the muonic molecules.

Science.gov (United States)

Rayka, Milad; Goli, Mohammad; Shahbazian, Shant

2018-03-28

A set of effective electronic-only Kohn-Sham (EKS) equations are derived for the muonic molecules (containing a positively charged muon), which are completely equivalent to the coupled electronic-muonic Kohn-Sham equations derived previously within the framework of the nuclear-electronic orbital density functional theory (NEO-DFT). The EKS equations contain effective non-coulombic external potentials depending on parameters describing the muon's vibration, which are optimized during the solution of the EKS equations making the muon's KS orbital reproducible. It is demonstrated that the EKS equations are derivable from a certain class of effective electronic Hamiltonians through applying the usual Hohenberg-Kohn theorems revealing a "duality" between the NEO-DFT and the effective electronic-only DFT methodologies. The EKS equations are computationally applied to a small set of muoniated organic radicals and it is demonstrated that a mean effective potential may be derived for this class of muonic species while an electronic basis set is also designed for the muon. These computational ingredients are then applied to muoniated ferrocenyl radicals, which had been previously detected experimentally through adding a muonium atom to ferrocene. In line with previous computational studies, from the six possible species, the staggered conformer, where the muon is attached to the exo position of the cyclopentadienyl ring, is deduced to be the most stable ferrocenyl radical.

Molecular effects in the neutrino mass determination from beta-decay of the tritium molecule

International Nuclear Information System (INIS)

Fackler, O.; Jeziorski, B.; Kolos, W.; Szalewicz, K.; Monkhorst, H.J.; Mugge, M.

1986-03-01

Molecular final state energies and transition probabilities have been computed for beta-decay of the tritium molecule. The results are of sufficient accuracy to make a determination of the electron neutrino rest mass with an error not exceeding a few tenths of an electron volt. Effects of approximate models of tritium beta-decay on the neutrino mass determination are discussed. 14 refs., 3 figs., 1 tab

Molecules in stars

International Nuclear Information System (INIS)

Tsuji, T.

1986-01-01

Recently, research related to molecules in stars has rapidly expanded because of progress in related fields. For this reason, it is almost impossible to cover all the topics related to molecules in stars. Thus, here the authors focus their attention on molecules in the atmospheres of cool stars and do not cover in any detail topics related to circumstellar molecules originating from expanding envelopes located far from the stellar surface. However, the authors do discuss molecules in quasi-static circumstellar envelopes (a recently discovered new component of circumstellar envelopes) located near the stellar surface, since molecular lines originating from such envelopes show little velocity shift relative to photospheric lines, and hence they directly affect the interpretation and analysis of stellar spectra

Radiation - induced changes in the optical properties of hemoglobin molecule

International Nuclear Information System (INIS)

Selim, N.S; El-Marakby, S.M.

2009-01-01

Adult male albino rats were exposed to different doses of gamma radiation from Cs-137 source. Hemoglobin samples were analyzed 24 hrs after irradiation. The UV-visible spectrum of hemoglobin molecule was measured in the range 200 to 700 nm. The overall spectrum of the hemoglobin molecule showed hypochromicity that increased with dose increase. To investigate the effect of radiation on the hemoglobin molecule, different parameters of the spectrum were calculated: molar absorption coefficient, absorption cross section, transition dipole moment , dipole length, the optical energy gap and activation energy for each characteristic peak. The obtained results revealed that the radiation effect can induce rearrangement of the transition dipole moments and change molecular energy levels of the hemoglobin molecule

Molecule Matters

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 14; Issue 4. Molecule Matters – van der Waals Molecules - History and Some Perspectives on Intermolecular Forces. E Arunan. Feature Article Volume 14 Issue 4 April 2009 pp 346-356 ...

Large tunable image-charge effects in single-molecule junctions.

NARCIS (Netherlands)

Perrin, M.L.; Verzijl, C.J.; Martin, C.A.; Shaikh, A.J.; Eelkema, R.; Esch, J.H. van; Ruitenbeek, J.M. van; Thijssen, J.M.; Zant, H.S. van der; Dulic, D.

2013-01-01

Metal/organic interfaces critically determine the characteristics of molecular electronic devices, because they influence the arrangement of the orbital levels that participate in charge transport. Studies on self-assembled monolayers show molecule-dependent energy-level shifts as well as

Quantum theory of anharmonic effects in molecules

CERN Document Server

Kazakov, Konstantin V

2012-01-01

Presented in a clear and straightforward analysis, this book explores quantum mechanics and the application of quantum mechanics to interpret spectral phenomena. Specifically, the book discusses the relation between spectral features in mid or rear infrared regions, or in Raman scattering spectrum, and interactions between molecules or molecular species such as molecular ions, and their respective motions in gaseous or crystalline conditions. Beginning with an overview of conventional methods and problems which arise in molecular spectroscopy, the second half of the book suggests original t

A binuclear Fe(III)Dy(III) single molecule magnet. Quantum effects and models.

Science.gov (United States)

Ferbinteanu, Marilena; Kajiwara, Takashi; Choi, Kwang-Yong; Nojiri, Hiroyuki; Nakamoto, Akio; Kojima, Norimichi; Cimpoesu, Fanica; Fujimura, Yuichi; Takaishi, Shinya; Yamashita, Masahiro

2006-07-19

The binuclear [FeIII(bpca)(mu-bpca)Dy(NO3)4], having Single Molecule Magnet (SMM) properties, belonging to a series of isostructural FeIIILnIII complexes (Ln = Eu, Gd, Tb, Dy, Ho) and closely related FeIILnIII chain structures, was characterized in concise experimental and theoretical respects. The low temperature magnetization data showed hysteresis and tunneling. The anomalous temperature dependence of Mössbauer spectra is related to the onset of magnetic order, consistent with the magnetization relaxation time scale resulting from AC susceptibility measurements. The advanced ab initio calculations (CASSCF and spin-orbit) revealed the interplay of ligand field, spin-orbit, and exchange effects and probed the effective Ising nature of the lowest states, involved in the SMM and tunneling effects.

Effects of Magnetic Field on the Valence Bond Property of the Double-Quantum-Dot Molecule

Institute of Scientific and Technical Information of China (English)

王立民; 罗莹; 马本堃

2002-01-01

The effects of the magnetic field on the valence bond property of the double-quantum-dot molecule are numerically studied by the finite element method and perturbation approach because of the absence of cylindrical symmetry in the horizontally coupled dots. The calculation results show that the energy value of the ground state changes differently from that of the first excited state with increasing magnetic field strength, and they cross under a certain magnetic field. The increasing magnetic field makes the covalent bond state change into an ionic bond state, which agrees qualitatively with experimental results and makes ionic bond states remain. The oscillator strength of transition between covalent bond states decreases distinctly with the increasing magnetic field strength, when the molecule is irradiated by polarized light. Such a phenomenon is possibly useful for actual applications.

Effects on the structure of monolayer and submonolayer fluid nitrogen films by the corrugation in the holding potential of nitrogen molecules

DEFF Research Database (Denmark)

Hansen, Flemming Yssing

2001-01-01

of interactions were indicated by the comparison of the calculated and measured isosteric heats of adsorption in fluid films of nitrogen molecules on graphite. The melting temperatures were lowered by 7K and a region of liquid-gas coexistence was observed for films on the smooth graphite surface indicating......The effects of corrugation in the holding potential of nitrogen molecules on the structure of fluid monolayer and submonolayer films of the molecules on a solid substrate was studied using molecular dynamics simulation. Including McLachlan mediation of the intermolecular potential in a model...

Electrochemical proton relay at the single-molecule level

DEFF Research Database (Denmark)

Kuznetsov, A. M.; Medvedev, I. G.; Ulstrup, Jens

2009-01-01

A scheme for the experimental study of single-proton transfer events, based on proton-coupled two-electron transfer between a proton donor and a proton acceptor molecule confined in the tunneling gap between two metal leads in electrolyte solution is suggested. Expressions for the electric current...... are derived and compared with formalism for electron tunneling through redox molecules. The scheme allows studying the kinetics of proton and hydrogen atom transfer as well as kinetic isotope effects at the single-molecule level under electrochemical potential control....

Simulations of the Static Friction Due to Adsorbed Molecules

OpenAIRE

He, Gang; Robbins, Mark O.

2001-01-01

The static friction between crystalline surfaces separated by a molecularly thin layer of adsorbed molecules is calculated using molecular dynamics simulations. These molecules naturally lead to a finite static friction that is consistent with macroscopic friction laws. Crystalline alignment, sliding direction, and the number of adsorbed molecules are not controlled in most experiments and are shown to have little effect on the friction. Temperature, molecular geometry and interaction potenti...

Effect of substrate thickness on ejection of phenylalanine molecules adsorbed on free-standing graphene bombarded by 10 keV C{sub 60}

Energy Technology Data Exchange (ETDEWEB)

Golunski, M. [Institute of Physics, Jagiellonian University, ul. Lojasiewicza 11, 30-348 Krakow (Poland); Verkhoturov, S.V.; Verkhoturov, D.S.; Schweikert, E.A. [Department of Chemistry, Texas A& M University, College Station, TX 77840 (United States); Postawa, Z., E-mail: zbigniew.postawa@uj.edu.pl [Institute of Physics, Jagiellonian University, ul. Lojasiewicza 11, 30-348 Krakow (Poland)

2017-02-15

Highlights: • Substrate thickness has a prominent effect on the molecular ejection mechanism. • Collisions with projectile atoms leads to molecular ejection at thin substrates. • Interactions with deforming graphene sheet ejects molecules from thicker substrates. • Probability of fragmentation process decreases with the graphene substrate thickness. - Abstract: Molecular dynamics computer simulations have been employed to investigate the effect of substrate thickness on the ejection mechanism of phenylalanine molecules deposited on free-standing graphene. The system is bombarded from the graphene side by 10 keV C{sub 60} projectiles at normal incidence and the ejected particles are collected both in transmission and reflection directions. It has been found that the ejection mechanism depends on the substrate thickness. At thin substrates mostly organic fragments are ejected by direct collisions between projectile atoms and adsorbed molecules. At thicker substrates interaction between deforming topmost graphene sheet and adsorbed molecules becomes more important. As this process is gentle and directionally correlated, it leads predominantly to ejection of intact molecules. The implications of the results to a novel analytical approach in Secondary Ion Mass Spectrometry based on ultrathin free-standing graphene substrates and a transmission geometry are discussed.

Development of a GIS-Based Decision Support System for Diagnosis of River System Health and Restoration

Directory of Open Access Journals (Sweden)

Jihong Xia

2014-10-01

Full Text Available The development of a decision support system (DSS to inform policy making has been progressing rapidly. This paper presents a generic framework and the development steps of a decision tool prototype of geographic information systems (GIS-based decision support system of river health diagnosis (RHD-DSS. This system integrates data, calculation models, and human knowledge of river health status assessment, causal factors diagnosis, and restoration decision making to assist decision makers during river restoration and management in Zhejiang Province, China. Our RHD-DSS is composed of four main elements: the graphical user interface (GUI, the database, the model base, and the knowledge base. It has five functional components: the input module, the database management, the diagnostic indicators management, the assessment and diagnosis, and the visual result module. The system design is illustrated with particular emphasis on the development of the database, model schemas, diagnosis and analytical processing techniques, and map management design. Finally, the application of the prototype RHD-DSS is presented and implemented for Xinjiangtang River of Haining County in Zhejiang Province, China. This case study is used to demonstrate the advantages gained by the application of this system. We conclude that there is great potential for using the RHD-DSS to systematically manage river basins in order to effectively mitigate environmental issues. The proposed approach will provide river managers and designers with improved insight into river degradation conditions, thereby strengthening the assessment process and the administration of human activities in river management.

An open-access mobile compatible electronic patient register for rheumatic heart disease (‘eRegister’) based on the World Heart Federation’s framework for patient registers

Science.gov (United States)

van Dam, Joris; Tadmor, Brigitta; Spector, Jonathan; Musuku, John; Zühlke, Liesl J; Zühlke, Liesl J; Engel, Mark E; Mayosi, Bongani M; Nestle, Nick

2015-01-01

Summary Background Rheumatic heart disease (RHD) remains a major disease burden in low-resource settings globally. Patient registers have long been recognised to be an essential instrument in RHD control and elimination programmes, yet to date rely heavily on paper-based data collection and non-networked data-management systems, which limit their functionality. Objectives To assess the feasibility and potential benefits of producing an electronic RHD patient register. Methods We developed an eRegister based on the World Heart Federation’s framework for RHD patient registers using CommCare, an open-source, cloud-based software for health programmes that supports the development of customised data capture using mobile devices. Results The resulting eRegistry application allows for simultaneous data collection and entry by field workers using mobile devices, and by providers using computer terminals in clinics and hospitals. Data are extracted from CommCare and are securely uploaded into a cloud-based database that matches the criteria established by the WHF framework. The application can easily be tailored to local needs by modifying existing variables or adding new ones. Compared with traditional paper-based data-collection systems, the eRegister reduces the risk of data error, synchronises in real-time, improves clinical operations and supports management of field team operations. Conclusions The user-friendly eRegister is a low-cost, mobile, compatible platform for RHD treatment and prevention programmes based on materials sanctioned by the World Heart Federation. Readily adaptable to local needs, this paperless RHD patient register program presents many practical benefits. PMID:26444995

Echocardiographic Screening of Rheumatic Heart Disease in American Samoa.

Science.gov (United States)

Huang, Jennifer H; Favazza, Michael; Legg, Arthur; Holmes, Kathryn W; Armsby, Laurie; Eliapo-Unutoa, Ipuniuesea; Pilgrim, Thomas; Madriago, Erin J

2018-01-01

While rheumatic heart disease (RHD) is a treatable disease nearly eradicated in the United States, it remains the most common form of acquired heart disease in the developing world. This study used echocardiographic screening to determine the prevalence of RHD in children in American Samoa. Screening took place at a subset of local schools. Private schools were recruited and public schools underwent cluster randomization based on population density. We collected survey information and performed a limited physical examination and echocardiogram using the World Heart Federation protocol for consented school children aged 5-18 years old. Of 2200 students from two private high schools and two public primary schools, 1058 subjects consented and were screened. Overall, 133 (12.9%) children were identified as having either definite (3.5%) or borderline (9.4%) RHD. Of the patients with definitive RHD, 28 subjects had abnormal mitral valves with pathologic regurgitation, three mitral stenosis, three abnormal aortic valves with pathologic regurgitation, and seven borderline mitral and aortic valve disease. Of the subjects with borderline disease, 77 had pathologic mitral regurgitation, 12 pathologic aortic regurgitation, and 7 at least two features of mitral valve disease without pathologic regurgitation or stenosis. Rheumatic heart disease remains a major cause of morbidity and mortality worldwide. The prevalence of RHD in American Samoa (12.9%) is to date the highest reported in the world literature. Echocardiographic screening of school children is feasible, while reliance on murmur and Jones criteria is not helpful in identifying children with RHD.

Jahn-Teller effect in vanadium, niobium and tantalum tetrafluoride molecules: ab initio study by the CASSCF method

International Nuclear Information System (INIS)

Solomonik, V.G.; Pogrebnaya, T.P.

2001-01-01

The basic and the first exciting electronic state of the VF 4 , NbF 4 and TaF 4 molecules were studied by the self-consistent field multifunctional method in the approximation of active orbitals full space. The symmetry of these states is defined as 2 E and 2 T 2 at tetrahedron configuration of the nuclei. The energies of electron excitation 2 E → 2 T 2 comprise 11610 (VF 4 ), 13450 (NbF 4 ) and 12560 cm -1 (TaF 4 ). In line to Jahn-Teller theorem the calculations evidenced instability of tetrahedron configuration of the molecules in the orbital-singular electronic states 2 E and 2 T 2 . The properties of the systems of the molecule potential energies were found, in keeping with deformation of tetrahedron configuration of the nuclei along the oscillation coordinates of the e symmetry, active in the Jahn-Teller effect. Equilibrium geometric configuration of the molecules with the lowest energy has a symmetry D 2d as in the basic ( 2 A 1 ), so in the first excited electronic state. The energy of the adiabatic electronic excitation 2 A 1 → 2 B 2 is equal to 8440 (VF 4 ), 9050 (NbF 4 ) and 11920 cm -1 (TaF 4 ). Deviations of molecules equilibrium geometry on the structure of the normal tetrahedron and the energy of Jahn-Teller stabilization E JT grow essentially in the series of the molecules VF 4 → NbF 4 → TaF 4 : E JT =E(T d , 2 E)Epy - E(D 2d , 2 A 1 )=412, 1856, 5970 cm -1 ; E JT =E(T d , 2 T 2 ) - E(D 2d , 2 B 2 )=3584, 6259, 6611 cm -1 . The quadratic force constants, the frequencies of normal oscillations and the intensities in the IR spectra of the VF 4 , NbF 4 and TaF 4 molecules in the basic state were calculated [ru

Exotic helium molecules; Molecules exotiques d'helium

Energy Technology Data Exchange (ETDEWEB)

Portier, M

2007-12-15

We study the photo-association of an ultracold cloud of magnetically trapped helium atoms: pairs of colliding atoms interact with one or two laser fields to produce a purely long range {sup 4}He{sub 2}(2{sup 3}S{sub 1}-2{sup 3}P{sub 0}) molecule, or a {sup 4}He{sub 2}(2{sup 3}S{sub 1}-2{sup 3}S{sub 1}) long range molecule. Light shifts in one photon photo-association spectra are measured and studied as a function of the laser polarization and intensity, and the vibrational state of the excited molecule. They result from the light-induced coupling between the excited molecule, and bound and scattering states of the interaction between two metastable atoms. Their analysis leads to the determination of the scattering length a = (7.2 {+-} 0.6) ruling collisions between spin polarized atoms. The two photon photo-association spectra show evidence of the production of polarized, long-range {sup 4}He{sub 2}(2{sup 3}S{sub 1}-2{sup 3}S{sub 1}) molecules. They are said to be exotic as they are made of two metastable atoms, each one carrying a enough energy to ionize the other. The corresponding lineshapes are calculated and decomposed in sums and products of Breit-Wigner and Fano profiles associated to one and two photon processes. The experimental spectra are fit, and an intrinsic lifetime {tau} = (1.4 {+-} 0.3) {mu}s is deduced. It is checked whether this lifetime could be limited by spin-dipole induced Penning autoionization. This interpretation requires that there is a quasi-bound state close to the dissociation threshold in the singlet interaction potential between metastable helium atoms for the theory to match the experiment. (author)

Bias voltage induced resistance switching effect in single-molecule magnets’ tunneling junction

Science.gov (United States)

Zhang, Zhengzhong; Jiang, Liang

2014-09-01

An electric-pulse-induced reversible resistance change effect in a molecular magnetic tunneling junction, consisting of a single-molecule magnet (SMM) sandwiched in one nonmagnetic and one ferromagnetic electrode, is theoretically investigated. By applying a time-varying bias voltage, the SMM's spin orientation can be manipulated with large bias voltage pulses. Moreover, the different magnetic configuration at high-resistance/low-resistance states can be ‘read out’ by utilizing relative low bias voltage. This device scheme can be implemented with current technologies (Khajetoorians et al 2013 Science 339 55) and has potential application in molecular spintronics and high-density nonvolatile memory devices.

Bias voltage induced resistance switching effect in single-molecule magnets' tunneling junction.

Science.gov (United States)

Zhang, Zhengzhong; Jiang, Liang

2014-09-12

An electric-pulse-induced reversible resistance change effect in a molecular magnetic tunneling junction, consisting of a single-molecule magnet (SMM) sandwiched in one nonmagnetic and one ferromagnetic electrode, is theoretically investigated. By applying a time-varying bias voltage, the SMM's spin orientation can be manipulated with large bias voltage pulses. Moreover, the different magnetic configuration at high-resistance/low-resistance states can be 'read out' by utilizing relative low bias voltage. This device scheme can be implemented with current technologies (Khajetoorians et al 2013 Science 339 55) and has potential application in molecular spintronics and high-density nonvolatile memory devices.

Noninvasive determination of fetal rh blood group, D antigen status by cell-free DNA analysis in maternal plasma: experience in a Brazilian population.

Science.gov (United States)

Chinen, Paulo Alexandre; Nardozza, Luciano Marcondes Machado; Martinhago, Ciro Dresch; Camano, Luiz; Daher, Silvia; Pares, David Baptista da Silva; Minett, Thais; Araujo Júnior, Edward; Moron, Antonio Fernandes

2010-11-01

We evaluated the diagnostic accuracy of Rh blood group, D antigen (RHD) fetal genotyping, using real-time polymerase chain reaction in maternal blood samples, in a racially mixed population. We performed a prospective study conducted between January 2006 and December 2007, analyzing fetal RHD genotype in the plasma of 102 D- pregnant women by real-time polymerase chain reaction, targeting exons 7 and 10 of the RHD gene. Genotype results were compared with cord blood phenotype obtained after delivery or before the first intrauterine transfusion when necessary. Most of the participants (75.5%) were under 28 weeks of pregnancy, and 87.5% had at least one relative of black ancestry. By combining amplification of two exons, the accuracy of genotyping was 98%, sensitivity was 100%, and specificity was 92%. The positive likelihood ratio was 12.5, and the negative likelihood ratio was 0. The two false-positive cases were confirmed to be pseudogene RHD by real-time polymerase chain reaction. There were no differences between the patients with positive or negative Coombs test ( P = 0.479). Determination of fetal RHD status in maternal peripheral blood was highly sensitive in this racially mixed population and was not influenced by the presence of antierythrocyte antibodies. © Thieme Medical Publishers.

Angiotensin Converting Enzyme Gene I/D Polymorphism in Pakistani Rheumatic Heart Disease Patients and Healthy Controls

Directory of Open Access Journals (Sweden)

Sadia Rehman

2015-09-01

Full Text Available Background: Valve scarring and collagen deposition are crucial in pathogenesis of Rheumatic Heart Disease (RHD, an autoimmune disorder of the heart. Angiotensin I-Converting Enzyme (ACE plays a major role in fibrous tissue formation. Objectives: The present research work aimed to assess the role of ACE Insertion/Deletion (I/D polymorphism in progress of RHD. Patients and Methods: DNA was pre pared from blood samples from 156 RHD patients (156 and 204 healthy ethnically-matched controls. Then, it was screened using sequence-specific Primers. Polymerase chain reaction and Agarose gel electrophoresis. The data were analyzed using Vassar stats (http://faculty.vassar.edu/lowry/VassarStats.html. Results: I allele (P = 0.024, OR = 1.42 and II genotype (P = 0.001, OR = 3.07 were significantly higher in Pakistani RHD patients compared to the healthy controls. Also, a significant difference was found between the female, but not male, patients and the controls regarding I allele and II genotype. Conclusions: The study results provided information about involvement of ACE I/D polymorphism in molecular mechanism of RHD. Thus, it can become one of the useful tools in risk assessment and help with designing strategies to combat the disease.

The status of molecules

International Nuclear Information System (INIS)

Barnes, T.; Oak Ridge National Lab., TN; Tennessee Univ., Knoxville, TN

1994-06-01

This report summarizes the experimental and theoretical status of hadronic molecules, which are weakly-bound states of two or more hadrons. We begin with a brief history of the subject and discuss a few good candidates, and then abstract some signatures for molecules which may be of interest in the classification of possible molecule states. Next we argue that a more general understanding of 2 → 2 hadron-hadron scattering amplitudes will be crucial for molecule searches, and discuss some of our recent work in this area. We conclude with a discussion of a few more recent molecule candidates (notably the f o (1710)) which are not well established as molecules but satisfy some of the expected signatures. (Author)

EDITORIAL: Focus on Cold and Ultracold Molecules FOCUS ON COLD AND ULTRACOLD MOLECULES

Science.gov (United States)

Carr, Lincoln D.; Ye, Jun

2009-05-01

öhlich, A Griesmaier, T Pfau, H Saito, Y Kawaguchi and M Ueda High-energy-resolution molecular beams for cold collision studies L P Parazzoli, N Fitch, D S Lobser and H J Lewandowski Collisional effects in the formation of cold guided beams of polar molecules M Motsch, C Sommer, M Zeppenfeld, L D van Buuren, P W H Pinkse and G Rempe Towards sympathetic cooling of large molecules: cold collisions between benzene and rare gas atoms P Barletta, J Tennyson and P F Barker Efficient formation of ground-state ultracold molecules via STIRAP from the continuum at a Feshbach resonance Elena Kuznetsova, Marko Gacesa, Philippe Pellegrini, Susanne F Yelin and Robin Côté Emergent timescales in entangled quantum dynamics of ultracold molecules in optical lattices M L Wall and L D Carr Rotational state resolved photodissociation spectroscopy of translationally and vibrationally cold MgH+ ions: toward rotational cooling of molecular ions K Højbjerre, A K Hansen, P S Skyt, P F Staanum and M Drewsen Collective transverse cavity cooling of a dense molecular beam Thomas Salzburger and Helmut Ritsch A Stark decelerator on a chip Samuel A Meek, Horst Conrad and Gerard Meijer Deceleration of molecules by dipole force potential: a numerical simulation Susumu Kuma and Takamasa Momose Ultracold molecules: vehicles to scalable quantum information processing Kathy-Anne Brickman Soderberg, Nathan Gemelke and Cheng Chin Magnetic field modification of ultracold molecule-molecule collisions T V Tscherbul, Yu V Suleimanov, V Aquilanti and R V Krems Spectroscopy of 39K85Rb triplet excited states using ultracold a 3Σ+ state molecules formed by photoassociation J T Kim, D Wang, E E Eyler, P L Gould and W C Stwalley Pumping vortex into a Bose-Einstein condensate of heteronuclear molecules Z F Xu, R Q Wang and L You Intense atomic and molecular beams via neon buffer-gas cooling David Patterson, Julia Rasmussen and John M Doyle Dynamical properties of dipolar Fermi gases T Sogo, L He, T Miyakawa, S Yi, H Lu

Giant Magnetoresistance in Carbon Nanotubes with Single-Molecule Magnets TbPc2.

Science.gov (United States)

Krainov, Igor V; Klier, Janina; Dmitriev, Alexander P; Klyatskaya, Svetlana; Ruben, Mario; Wernsdorfer, Wolfgang; Gornyi, Igor V

2017-07-25

We present experimental results and a theoretical model for the gate-controlled spin-valve effect in carbon nanotubes with side-attached single-molecule magnets TbPc 2 (Terbium(III) bis-phthalocyanine). These structures show a giant magnetoresistance up to 1000% in experiments on single-wall nanotubes that are tunnel-coupled to the leads. The proposed theoretical model combines the spin-dependent Fano effect with Coulomb blockade and predicts a spin-spin interaction between the TbPc 2 molecules, mediated by conducting electrons via the charging effect. This gate-tuned interaction is responsible for the stable magnetic ordering of the inner spins of the molecules in the absence of magnetic field. In the case of antiferromagnetic arrangement, electrons with either spin experience the scattering by the molecules, which results in blocking the linear transport. In strong magnetic fields, the Zeeman energy exceeds the effective antiferromagnetic coupling and one species of electrons is not scattered by molecules, which leads to a much lower total resistance at the resonant values of gate voltage, and hence to a supramolecular spin-valve effect.

Coinhibitory molecules in cancer biology and therapy.

Science.gov (United States)

Mocellin, Simone; Benna, Clara; Pilati, Pierluigi

2013-04-01

The adaptive immune response is controlled by checkpoints represented by coinhibitory molecules, which are crucial for maintaining self-tolerance and minimizing collateral tissue damage under physiological conditions. A growing body of preclinical evidence supports the hypothesis that unleashing this immunological break might be therapeutically beneficial in the fight against cancer, as it would elicit an effective antitumor immune response. Remarkably, recent clinical trials have demonstrated that this novel strategy can be highly effective in the treatment of patients with cancer, as shown by the paradigmatic case of ipilimumab (a monoclonal antibody blocking the coinhibitory molecule cytotoxic T lymphocyte associated antigen-4 [CTLA4]) that is opening a new era in the therapeutic approach to a chemoresistant tumor such as cutaneous melanoma. In this review we summarize the biology of coinhibitory molecules, overview the experimental and clinical attempts to interfere with these immune checkpoints to treat cancer and critically discuss the challenges posed by such a promising antitumor modality. Copyright © 2013 Elsevier Ltd. All rights reserved.

Single-molecule study on polymer diffusion in a melt state: Effect of chain topology

KAUST Repository

Habuchi, Satoshi

2013-08-06

We report a new methodology for studying diffusion of individual polymer chains in a melt state, with special emphasis on the effect of chain topology. A perylene diimide fluorophore was incorporated into the linear and cyclic poly(THF)s, and real-time diffusion behavior of individual chains in a melt of linear poly(THF) was measured by means of a single-molecule fluorescence imaging technique. The combination of mean squared displacement (MSD) and cumulative distribution function (CDF) analysis demonstrated the broad distribution of diffusion coefficient of both the linear and cyclic polymer chains in the melt state. This indicates the presence of spatiotemporal heterogeneity of the polymer diffusion which occurs at much larger time and length scales than those expected from the current polymer physics theory. We further demonstrated that the cyclic chains showed marginally slower diffusion in comparison with the linear counterparts, to suggest the effective suppression of the translocation through the threading-entanglement with the linear matrix chains. This coincides with the higher activation energy for the diffusion of the cyclic chains than of the linear chains. These results suggest that the single-molecule imaging technique provides a powerful tool to analyze complicated polymer dynamics and contributes to the molecular level understanding of the chain interaction. © 2013 American Chemical Society.

Single-molecule study on polymer diffusion in a melt state: Effect of chain topology

KAUST Repository

Habuchi, Satoshi; Fujiwara, Susumu; Yamamoto, Takuya; Vá cha, Martin; Tezuka, Yasuyuki

2013-01-01

We report a new methodology for studying diffusion of individual polymer chains in a melt state, with special emphasis on the effect of chain topology. A perylene diimide fluorophore was incorporated into the linear and cyclic poly(THF)s, and real-time diffusion behavior of individual chains in a melt of linear poly(THF) was measured by means of a single-molecule fluorescence imaging technique. The combination of mean squared displacement (MSD) and cumulative distribution function (CDF) analysis demonstrated the broad distribution of diffusion coefficient of both the linear and cyclic polymer chains in the melt state. This indicates the presence of spatiotemporal heterogeneity of the polymer diffusion which occurs at much larger time and length scales than those expected from the current polymer physics theory. We further demonstrated that the cyclic chains showed marginally slower diffusion in comparison with the linear counterparts, to suggest the effective suppression of the translocation through the threading-entanglement with the linear matrix chains. This coincides with the higher activation energy for the diffusion of the cyclic chains than of the linear chains. These results suggest that the single-molecule imaging technique provides a powerful tool to analyze complicated polymer dynamics and contributes to the molecular level understanding of the chain interaction. © 2013 American Chemical Society.

Research on effects of ionizing radiation of human peripheral blood white cell adhesive molecules

International Nuclear Information System (INIS)

Li Haijun; Cheng Ying; Le Chen; Min Rui

2008-01-01

Objective: To investigate the links between expression and function of adhesive molecule on the surface of irradiated peripheral blood white cells. Methods: Heparinized human peripheral blood was exposed to γ rays with different dose. At the different post-radiation time adhesive molecule expression on cellular surface was determined by double fluorescence labeling antibodies which were against adhesive molecule and special mark of granulocyte or mononuclear cell respectively with flow cytometry, and cellular adhesive ability to different matrixes mediated by adhesive molecule was estimated by commercializing enzyme-linked immunosorbent assay kit and crystalviolet dying. Results: A decline pattern of CD11b on surface of mononuclear cells and CD29 on surface of granulocyte with irradiation dose increase was found. The changes of adhesive ability of mononuclear cells to substance of β1-integrin and collagen-I was well related with irradiation dose. Conclusion: Good relationship shown by the changes of adhesive molecule expression and adhesive ability mediated by the molecules on the surface of peripheral blood white cells with radiation dose was primary base of further research on indicting exposure dose by biomarker. (authors)

Strategy to discover diverse optimal molecules in the small molecule universe.

Science.gov (United States)

Rupakheti, Chetan; Virshup, Aaron; Yang, Weitao; Beratan, David N

2015-03-23

The small molecule universe (SMU) is defined as a set of over 10(60) synthetically feasible organic molecules with molecular weight less than ∼500 Da. Exhaustive enumerations and evaluation of all SMU molecules for the purpose of discovering favorable structures is impossible. We take a stochastic approach and extend the ACSESS framework ( Virshup et al. J. Am. Chem. Soc. 2013 , 135 , 7296 - 7303 ) to develop diversity oriented molecular libraries that can generate a set of compounds that is representative of the small molecule universe and that also biases the library toward favorable physical property values. We show that the approach is efficient compared to exhaustive enumeration and to existing evolutionary algorithms for generating such libraries by testing in the NKp fitness landscape model and in the fully enumerated GDB-9 chemical universe containing 3 × 10(5) molecules.

Hydrogen molecule defect in proton-conductive SrTiO3 Perovskite

Science.gov (United States)

Onishi, Taku

2017-11-01

In proton-conductive SrTiO3 perovskite, no hydrogen molecule defect ideally exists. However, the unforeseen chemical reaction is often observed after the use of fuel cell. From the viewpoint of battery safety, we have investigated the effect of hydrogen molecule defect by molecular orbital analysis. When counter cation vacancy exists, the activation energy for hydrogen molecule migration was 1.39 - 1.50 eV, which is much smaller than the dissociation energy of hydrogen molecule. It implies that hydrogen molecule may migrate without its dissociation.

Calculation of a hydrogen molecule in the adiabatic approximation

International Nuclear Information System (INIS)

Vukajlovich, F.R.; Mogilevskij, O.A.; Ponomarev, L.I.

1979-01-01

The adiabatic approximation js used for calculating the energy levels of a hydrogen molecule, i.e. of the simplest four-body system with a Coulomb interaction. The aim of this paper is the investigation of the possible use of the adiabatic method in the molecular problems. The most effective regions of its application are discussed. An infinite system of integro-differential equations is constructed, which describes the hydrogen molecule in the adiabatic approximation with the effective potentials taking into account the corrections to the nuclear motion. The energy of the first three vibrational states of the hydrogen molecule is calculated and compared with the experimental data. The convergence of the method is discussed

Genes, autoimmunity and pathogenesis of rheumatic heart disease

International Nuclear Information System (INIS)

Guilherme, L; Köhler, K F; Postol, E; Kalil, J

2011-01-01

Pathogenesis of rheumatic heart disease (RHD) remains incompletely understood. Several genes associated with RHD have been described; most of these are involved with immune responses. Single nucleotide polymorphisms in a number of genes affect patients with RHD compared to controls. Molecular mimicry between streptococcal antigens and human proteins, including cardiac myosin epitopes, vimentin and other intracellular proteins is central to the pathogenesis of RHD. Autoreactive T cells migrate from the peripheral blood to the heart and proliferate in the valves in response to stimulation with specific cytokines. The types of cells involved in the inflammation as well as different cytokine profiles in these patients are being investigated. High TNF alpha, interferon gamma, and low IL4 are found in the rheumatic valve suggesting an imbalance between Th1 and Th2 cytokines and probably contributing to the progressive and permanent valve damage. Animal model of ARF in the Lewis rat may further contribute towards understanding the ARF

Tuning the conductance of carbon nanotubes with encapsulated molecules

International Nuclear Information System (INIS)

Meunier, Vincent; Sumpter, Bobby G

2007-01-01

It was recently shown that a molecule encapsulated inside a carbon nanotube can be used to devise a novel type of non-volatile memory element. At the heart of the mechanism for storing and reading information is the new concept of a molecular gate where the molecule acts as a passive gate that hinders the flow of electrons for a given position relative to the nanotube host. By systematically exploring the effects of encapsulation of an acceptor molecule in a series of carbon nanotubes, we show that the reliability of the memory mechanism is very sensitive to the interaction between the nanotube host and the molecule guest

Contact-Engineered Electrical Properties of MoS2 Field-Effect Transistors via Selectively Deposited Thiol-Molecules.

Science.gov (United States)

Cho, Kyungjune; Pak, Jinsu; Kim, Jae-Keun; Kang, Keehoon; Kim, Tae-Young; Shin, Jiwon; Choi, Barbara Yuri; Chung, Seungjun; Lee, Takhee

2018-05-01

Although 2D molybdenum disulfide (MoS 2 ) has gained much attention due to its unique electrical and optical properties, the limited electrical contact to 2D semiconductors still impedes the realization of high-performance 2D MoS 2 -based devices. In this regard, many studies have been conducted to improve the carrier-injection properties by inserting functional paths, such as graphene or hexagonal boron nitride, between the electrodes and 2D semiconductors. The reported strategies, however, require relatively time-consuming and low-yield transfer processes on sub-micrometer MoS 2 flakes. Here, a simple contact-engineering method is suggested, introducing chemically adsorbed thiol-molecules as thin tunneling barriers between the metal electrodes and MoS 2 channels. The selectively deposited thiol-molecules via the vapor-deposition process provide additional tunneling paths at the contact regions, improving the carrier-injection properties with lower activation energies in MoS 2 field-effect transistors. Additionally, by inserting thiol-molecules at the only one contact region, asymmetric carrier-injection is feasible depending on the temperature and gate bias. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rheumatic Heart Disease Associated with Secondary Renal ...

African Journals Online (AJOL)

... non-specific chronic inflammatory changes. The patient's secondary amyloidosis was presumed to be related to the long standing RHD after exclusion of other causes of secondary amyloidosis. The patient finally died due to heart failure and acute pulmonary edema. Conclusion: Long standing RHD can lead to secondary ...

Root hair defective4 encodes a phosphatidylinositol-4-phosphate phosphatase required for proper root hair development in Arabidopsis thaliana

NARCIS (Netherlands)

Thole, J.M.; Vermeer, J.E.M.; Zhang, Y.; Gadella, Th.W.J.; Nielsen, E.

2008-01-01

Polarized expansion of root hair cells in Arabidopsis thaliana is improperly controlled in root hair-defective rhd4-1 mutant plants, resulting in root hairs that are shorter and randomly form bulges along their length. Using time-lapse fluorescence microscopy in rhd4-1 root hairs, we analyzed

Inference Generation during Text Comprehension by Adults with Right Hemisphere Brain Damage: Activation Failure Versus Multiple Activation.

Science.gov (United States)

Tompkins, Connie A.; Fassbinder, Wiltrud; Blake, Margaret Lehman; Baumgaertner, Annette; Jayaram, Nandini

2004-01-01

ourse comprehensionEvidence conflicts as to whether adults with right hemisphere brain damage (RHD) generate inferences during text comprehension. M. Beeman (1993) reported that adults with RHD fail to activate the lexical-semantic bases of routine bridging inferences, which are necessary for comprehension. But other evidence indicates that adults…

A Small Molecule-Screening Pipeline to Evaluate the Therapeutic Potential of 2-Aminoimidazole Molecules Against Clostridium difficile

Directory of Open Access Journals (Sweden)

Rajani Thanissery

2018-06-01

Full Text Available Antibiotics are considered to be the first line of treatment for mild to moderately severe Clostridium difficile infection (CDI in humans. However, antibiotics are also risk factors for CDI as they decrease colonization resistance against C. difficile by altering the gut microbiota and metabolome. Finding compounds that selectively inhibit different stages of the C. difficile life cycle, while sparing the indigenous gut microbiota is important for the development of alternatives to standard antibiotic treatment. 2-aminoimidazole (2-AI molecules are known to disrupt bacterial protection mechanisms in antibiotic resistant bacteria such as Pseudomonas aeruginosa, Acinetobacter baumannii, and Staphylococcus aureus, but are yet to be evaluated against C. difficile. A comprehensive small molecule-screening pipeline was developed to investigate how novel small molecules affect different stages of the C. difficile life cycle (growth, toxin, and sporulation in vitro, and a library of commensal bacteria that are associated with colonization resistance against C. difficile. The initial screening tested the efficacy of eleven 2-AI molecules (compound 1 through 11 against C. difficile R20291 compared to a vancomycin (2 μg/ml control. Molecules were selected for their ability to inhibit C. difficile growth, toxin activity, and sporulation. Further testing included growth inhibition of other C. difficile strains (CD196, M68, CF5, 630, BI9, M120 belonging to distinct PCR ribotypes, and a commensal panel (Bacteroides fragilis, B. thetaiotaomicron, C. scindens, C. hylemonae, Lactobacillus acidophilus, L. gasseri, Escherichia coli, B. longum subsp. infantis. Three molecules compound 1 and 2, and 3 were microbicidal, whereas compounds 4, 7, 9, and 11 inhibited toxin activity without affecting the growth of C. difficile strains and the commensal microbiota. The antimicrobial and anti-toxin effects of 2-AI molecules need to be further characterized for mode of

Dressed molecules in resonantly interacting ultracold atomic Fermi gases

NARCIS (Netherlands)

Falco, G.M.; Stoof, H.T.C.

2007-01-01

We present a detailed analysis of the two-channel atom-molecule effective Hamiltonian for an ultracold two-component homogeneous Fermi gas interacting near a Feshbach resonance. We particularly focus on the two-body and many-body properties of the dressed molecules in such a gas. An exact result

Exome-wide Association Study Identifies GREB1L Mutations in Congenital Kidney Malformations.

Science.gov (United States)

Sanna-Cherchi, Simone; Khan, Kamal; Westland, Rik; Krithivasan, Priya; Fievet, Lorraine; Rasouly, Hila Milo; Ionita-Laza, Iuliana; Capone, Valentina P; Fasel, David A; Kiryluk, Krzysztof; Kamalakaran, Sitharthan; Bodria, Monica; Otto, Edgar A; Sampson, Matthew G; Gillies, Christopher E; Vega-Warner, Virginia; Vukojevic, Katarina; Pediaditakis, Igor; Makar, Gabriel S; Mitrotti, Adele; Verbitsky, Miguel; Martino, Jeremiah; Liu, Qingxue; Na, Young-Ji; Goj, Vinicio; Ardissino, Gianluigi; Gigante, Maddalena; Gesualdo, Loreto; Janezcko, Magdalena; Zaniew, Marcin; Mendelsohn, Cathy Lee; Shril, Shirlee; Hildebrandt, Friedhelm; van Wijk, Joanna A E; Arapovic, Adela; Saraga, Marijan; Allegri, Landino; Izzi, Claudia; Scolari, Francesco; Tasic, Velibor; Ghiggeri, Gian Marco; Latos-Bielenska, Anna; Materna-Kiryluk, Anna; Mane, Shrikant; Goldstein, David B; Lifton, Richard P; Katsanis, Nicholas; Davis, Erica E; Gharavi, Ali G

2017-11-02

Renal agenesis and hypodysplasia (RHD) are major causes of pediatric chronic kidney disease and are highly genetically heterogeneous. We conducted whole-exome sequencing in 202 case subjects with RHD and identified diagnostic mutations in genes known to be associated with RHD in 7/202 case subjects. In an additional affected individual with RHD and a congenital heart defect, we found a homozygous loss-of-function (LOF) variant in SLIT3, recapitulating phenotypes reported with Slit3 inactivation in the mouse. To identify genes associated with RHD, we performed an exome-wide association study with 195 unresolved case subjects and 6,905 control subjects. The top signal resided in GREB1L, a gene implicated previously in Hoxb1 and Shha signaling in zebrafish. The significance of the association, which was p = 2.0 × 10 -5 for novel LOF, increased to p = 4.1 × 10 -6 for LOF and deleterious missense variants combined, and augmented further after accounting for segregation and de novo inheritance of rare variants (joint p = 2.3 × 10 -7 ). Finally, CRISPR/Cas9 disruption or knockdown of greb1l in zebrafish caused specific pronephric defects, which were rescued by wild-type human GREB1L mRNA, but not mRNA containing alleles identified in case subjects. Together, our study provides insight into the genetic landscape of kidney malformations in humans, presents multiple candidates, and identifies SLIT3 and GREB1L as genes implicated in the pathogenesis of RHD. Copyright © 2017 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Observing electron motion in molecules

International Nuclear Information System (INIS)

Chelkowski, S; Yudin, G L; Bandrauk, A D

2006-01-01

We study analytically the possibility for monitoring electron motion in a molecule using two ultrashort laser pulses. The first prepares a coherent superposition of two electronic molecular states whereas the second (attosecond pulse) photoionizes the molecule. We show that interesting information about electron dynamics can be obtained from measurement of the photoelectron spectra as a function of the time delay between two pulses. In particular, asymmetries in photoelectron angular distribution provide a simple signature of the electron motion within the initial time-dependent coherently coupled two molecular states. Both asymmetries and electron spectra show very strong two-centre interference patterns. We illustrate these effects using as an example a dissociating hydrogen molecular ion probed by the attosecond pulses

Dynamics of Activated Molecules

Energy Technology Data Exchange (ETDEWEB)

Mullin, Amy S. [Univ. of Maryland, College Park, MD (United States)

2016-11-16

Experimental studies have been performed to investigate the collisional energy transfer processes of gas-phase molecules that contain large amounts of internal energy. Such molecules are prototypes for molecules under high temperature conditions relevant in combustion and information about their energy transfer mechanisms is needed for a detailed understanding and modeling of the chemistry. We use high resolution transient IR absorption spectroscopy to measure the full, nascent product distributions for collisions of small bath molecules that relax highly vibrationally excited pyrazine molecules with E=38000 cm-1 of vibrational energy. To perform these studies, we developed new instrumentation based on modern IR light sources to expand our experimental capabilities to investigate new molecules as collision partners. This final report describes our research in four areas: the characterization of a new transient absorption spectrometer and the results of state-resolved collision studies of pyrazine(E) with HCl, methane and ammonia. Through this research we have gained fundamental new insights into the microscopic details of relatively large complex molecules at high energy as they undergo quenching collisions and redistribute their energy.

Counteracting chemical chaperone effects on the single-molecule α-synuclein structural landscape

OpenAIRE

Ferreon, Allan Chris M.; Moosa, Mahdi Muhammad; Gambin, Yann; Deniz, Ashok A.

2012-01-01

Protein structure and function depend on a close interplay between intrinsic folding energy landscapes and the chemistry of the protein environment. Osmolytes are small-molecule compounds that can act as chemical chaperones by altering the environment in a cellular context. Despite their importance, detailed studies on the role of these chemical chaperones in modulating structure and dimensions of intrinsically disordered proteins have been limited. Here, we used single-molecule Förster reson...

Matrix and substrate effects on the sputtering of a 2 kDa molecule: Insights from molecular dynamics

International Nuclear Information System (INIS)

Delcorte, A.; Arezki, B.; Garrison, B.J.

2003-01-01

In an effort towards a more accurate theoretical description of matrix and substrate effects in organic sputtering, we report on molecular dynamics simulations of the desorption induced by 500 eV Ar projectiles bombarding samples composed of polystyrene (PS) oligomers embedded in a trimethylbenzene matrix or cast on a silver substrate. The ejection of intact PS molecules, sometimes accompanied by matrix molecules/silver atoms, is observed in the first 10 ps following the impact. For the 'matrix' sample, the results indicate that the emission of large amounts of organic material is mostly vibrationally induced. Extended calculations show that matrix:analyte clusters decay after emission, liberating the analyte in flight. In the case of the 'substrate' sample, the emission is oftentimes the result of the concerted upward motion of several metal atoms underneath the molecule. Finally, the comparison between a matrix:analyte sample confined in a nanostructured silver crystal and a purely organic sample under identical bombardment conditions shows that the presence of the silver medium significantly enhances the desorption yields

Weak D Type 4.2.2 (DAR1.2) in an African child: Serology and molecular characterization.

Science.gov (United States)

Orlando, Nicoletta; Putzulu, Rossana; Massini, Giuseppina; Scavone, Fernando; Piccirillo, Nicola; Maresca, Maddalena; Zini, Gina; Teofili, Luciana

2015-04-01

The weak D phenotype is represented by a group of RHD genotypes that code for alterated RhD proteins associated with a reduced RhD expression on red blood cell. By routine serology, some partial D variants are likely to be missed. In this report we describe the case of a three-year-old Black African child with a "unclear" reaction with monoclonal anti-D. We analyzed the blood sample of the child with different methods to conclude that it is a case of DAR 1.2 (weak D 4.2.2) and that it must be transfused with D negative erithrocytes. Copyright © 2014 Elsevier Ltd. All rights reserved.

Human anti-rhesus D IgG1 antibody produced in transgenic plants

DEFF Research Database (Denmark)

Bouquin, Thomas; Thomsen, Mads; Nielsen, Leif Kofoed

2002-01-01

antigen, which is responsible for alloimmunization of RhD- mothers carrying an RhD+ fetus. Anti-RhD extracted from plants specifically reacted with RhD+ cells in antiglobulin technique, and elicited a respiratory burst in human peripheral blood mononuclear cells. Plant-derived antibody had equivalent......Transgenic plants represent an alternative to cell culture systems for producing cheap and safe antibodies for diagnostic and therapeutic use. To evaluate the functional properties of a 'plantibody', we generated transgenic Arabidopsis plants expressing full-length human IgG1 against the Rhesus D...... properties to CHO cell-produced anti-RhD antibody, indicating its potential usefulness in diagnostic and therapeutic programs....

Density, distribution, and orientation of water molecules inside and outside carbon nanotubes.

Science.gov (United States)

Thomas, J A; McGaughey, A J H

2008-02-28

The behavior of water molecules inside and outside 1.1, 2.8, 6.9, and 10.4 nm diameter armchair carbon nanotubes (CNTs) is predicted using molecular dynamics simulations. The effects of CNT diameter on mass density, molecular distribution, and molecular orientation are identified for both the confined and unconfined fluids. Within 1 nm of the CNT surface, unconfined water molecules assume a spatially varying density profile. The molecules distribute nonuniformly around the carbon surface and have preferred orientations. The behavior of the unconfined water molecules is invariant with CNT diameter. The behavior of the confined water, however, can be correlated to tube diameter. Inside the 10.4 nm CNT, the molecular behavior is indistinguishable from that of the unconfined fluid. Within the smaller CNTs, surface curvature effects reduce the equilibrium water density and force water molecules away from the surface. This effect changes both the molecular distribution and preferred molecular orientations.

Electron-molecule collisions

International Nuclear Information System (INIS)

Shimamura, I.; Takayanagi, K.

1984-01-01

The study of collision processes plays an important research role in modern physics. Many significant discoveries have been made by means of collision experiments. Based on theoretical, experimental, and computational studies, this volume presents an overview detailing the basic processes of electron-molecule collisions. The editors have collected papers-written by a group of international experts-that consider a diverse range of phenomena occurring in electronmolecule collisions. The volume discusses first the basic formulation for scattering problems and then gives an outline of the physics of electron-molecule collisions. The main topics covered are rotational transitions, vibrational transitions, dissociation of molecules in slow collisions, the electron-molecule collision as a spectroscopic tool for studying molecular electronic structures, and experimental and computational techniques for determining the cross sections. These well-referenced chapters are self-contained and can be read independently or consecutively. Authoritative and up-to-date, Electron-Molecule Collisions is a useful addition to the libraries of students and researchers in the fields of atomic, molecular, and chemical physics, and physical chemistry

Rheumatic heart disease and the asap programme: fresh insights ...

African Journals Online (AJOL)

rheumatic heart disease (RHD), which could potentially result in 1.4 million deaths per year from the disease and its complications.2 These individuals are predominantly children, adolescents and young adults who live in poor and under-resourced areas of the world. Current epidemiology. The prevalence of RHD has ...

Rh Variability in Multi-Ethnic Perspective: Consequences for RH Genotyping

NARCIS (Netherlands)

G.H.M. Tax

2006-01-01

textabstractThe RhD bloodgroup was first described by Levine en Stetson in 1939 after the manifestation of a hemolytic transfusion reaction in a woman who recently gave birth, after transfusion with her husbands red cells. The RhD-negative woman produced antibodies against the RhD present on the

Comprehensive Map of Molecules Implicated in Obesity.

Directory of Open Access Journals (Sweden)

Jaisri Jagannadham

Full Text Available Obesity is a global epidemic affecting over 1.5 billion people and is one of the risk factors for several diseases such as type 2 diabetes mellitus and hypertension. We have constructed a comprehensive map of the molecules reported to be implicated in obesity. A deep curation strategy was complemented by a novel semi-automated text mining system in order to screen 1,000 full-length research articles and over 90,000 abstracts that are relevant to obesity. We obtain a scale free network of 804 nodes and 971 edges, composed of 510 proteins, 115 genes, 62 complexes, 23 RNA molecules, 83 simple molecules, 3 phenotype and 3 drugs in "bow-tie" architecture. We classify this network into 5 modules and identify new links between the recently discovered fat mass and obesity associated FTO gene with well studied examples such as insulin and leptin. We further built an automated docking pipeline to dock orlistat as well as other drugs against the 24,000 proteins in the human structural proteome to explain the therapeutics and side effects at a network level. Based upon our experiments, we propose that therapeutic effect comes through the binding of one drug with several molecules in target network, and the binding propensity is both statistically significant and different in comparison with any other part of human structural proteome.

Dynamics of hadronic molecule in one-boson exchange approach and possible heavy flavor molecules

International Nuclear Information System (INIS)

Ding Guijun; Liu Jiafeng; Yan Mulin

2009-01-01

We extend the one pion exchange model at quark level to include the short distance contributions coming from η, σ, ρ and ω exchange. This formalism is applied to discuss the possible molecular states of DD*/DD*, BB*/BB*, DD*, BB*, the pseudoscalar-vector systems with C=B=1 and C=-B=1 respectively. The ''δ function'' term contribution and the S-D mixing effects have been taken into account. We find the conclusions reached after including the heavier mesons exchange are qualitatively the same as those in the one pion exchange model. The previous suggestion that 1 ++ BB*/BB* molecule should exist, is confirmed in the one-boson exchange model, whereas DD* bound state should not exist. The DD*/DD* system can accommodate a 1 ++ molecule close to the threshold, the mixing between the molecule and the conventional charmonium has to be considered to identify this state with X(3872). For the BB* system, the pseudoscalar-vector systems with C=B=1 and C=-B=1, near threshold molecular states may exist. These bound states should be rather narrow, isospin is violated and the I=0 component is dominant. Experimental search channels for these states are suggested.

Effects of phytoestrogens derived from soy bean on expression of adhesion molecules on HUVEC.

Science.gov (United States)

Andrade, C M de; Sá, M F Silva de; Toloi, M R Torqueti

2012-04-01

The risks of hormone replacement therapy have led to a search for new alternatives such as phytoestrogens, plant compounds with estrogen-like biological activity. Isoflavones are the phytoestrogens most extensively studied and can be found in soybean, red clover and other plants. Due to this estrogen-like activity, phytoestrogens can have some effect on atherosclerosis. Human umbilical vein endothelial cells (HUVEC) have been extensively used to study the biology and pathobiology of human endothelial cells and most of the knowledge acquired is due to experiments with cultures of these cells. To evaluate the effects of the phytoestrogen extracts from Glycine max soy bean, genistein, formononetin, biochanin A and daidzein, as well as a mixture of these extracts (Mix), on expression of adhesion molecules, VCAM-1, ICAM-1 and E-selectin, by endothelial cell HUVEC, stimulated with lipopolysaccharide. HUVEC were cultured in medium EBM(2), pretreated with isoflavones for 24 and 48 h and then stimulated with lipopolysaccharide; in addition, isoflavones were added, after stimulation by lipopolysaccharide, to HUVEC. We evaluated the production of VCAM-1, ICAM-1 and E-selectin on cell surface, by cell-based enzyme immunoassay, and of sVCAM-1, sICAM-1 and sE-selectin in culture supernatant, by ELISA. Genistein, formononetin, biochanin A and daidzein, as well as the Mix were able to reduce VCAM-1, ICAM-1 and E-selectin on cell surface and in culture supernatant. Conclusion Isoflavones extracted from Glycine max soy bean, in vitro, presented antiatherogenic effects, reducing the expression of adhesion molecules and acting as preventive agents as well as therapeutic agents.

Evaluation of proinflammatory cytokines and brain natriuretic peptide in patients with rheumatic heart diseases and coronary heart disease complicated by chronic heart insufficiency

Directory of Open Access Journals (Sweden)

N A Shoslak

2005-01-01

Full Text Available Objective. To study proinflammatory cytokines and brain natriuretic peptide (BNP in patients with rheumatic heart diseases (RHD and coronary heart disease (CHD complicated by chronic heart insufficiency (CHI. Material and methods. 54 pts with CHI (among them 16 with RHD and 38 with CHD with signs of CHI ofll-IV functional class according to NYHA that correspond to 11A-III stage according to N.D. Strazesko-V.H. \\frsilenko classification and 30 healthy persons of control group were examined. Besides clinical evaluation common laboratory and instrumental methods were used. Thorough echocardiography analysis, quantitative evaluation of serum TNF a, IL6 and BNP by immuno-enzyme assay was performed. Results. Direct correlation between cytokines and BNP levels and pts with CHI clinical state severity was revealed. These indiccs significantly differed in coronary and non-coronary (RHD CHI. TNF a concentration was minimal in mitral stenosis. Maximal concentrations of IL6 and TNF a were revealed in tricuspid regurgitation. TNF a concentration elevated with increase of heart linear dimensions. BNP showed similar but less prominent tendencies. Conclusion. Significant difference of studied indices in coronary and non-coronary (RHD CHI was shown. Despite of similarity of CHI clinical features levels of inflammation biological indices in RHD was significantly lower than in CHD that requires further discussion.

The assessment of pragmatics in Iranian patients with right brain damage.

Science.gov (United States)

Sobhani-Rad, Davood; Ghorbani, Askar; Ashayeri, Hassan; Jalaei, Shohereh; Mahmoodi-Bakhtiari, Behrooz

2014-04-03

Pragmatics is appropriate use of language across a variety of social contexts that provides accurate interpretation of intentions. The occurrence of the right hemisphere lesions can interfere with pragmatic abilities, and particularly with the processing of nonliteral speech acts. Since the objective of this study was to assess different aspects of pragmatic competence in the right hemisphere damage (RHD) patients, 20 Iranian patients with right hemisphere lesions were examined by adult pragmatic profile (APP) and a novel checklist was introduced for Persian language speaking individuals. Meanwhile, 40 healthy adult individuals, who were age and gender matched with RHD patients, were considered as the control group. After obtaining video records, all subjects were evaluated for 35 pragmatic skills, including 24 verbal, 5 paralinguistic, and 6 nonverbal aspects, by a two-point scale system. Studying RHD patients and their healthy counterparts revealed that the performance by participants with right hemisphere lesions exhibited a high degree of inappropriate pragmatic abilities compared with controls in all domains. Furthermore, RHD patients showed a trend of increasing difficulty in understanding and producing different pragmatic phenomena, including standard communication acts. Present results indicated that the right hemisphere lesions significantly affected pragmatic abilities in verbal, paralinguistic and nonverbal aspects. Such a pattern of performance, which is in line with deficits previously reported for RHD, proved the unquestioned role of the right hemisphere in processing nonliteral language.

Exotic helium molecules; Molecules exotiques d'helium

Energy Technology Data Exchange (ETDEWEB)

Portier, M

2007-12-15

We study the photo-association of an ultracold cloud of magnetically trapped helium atoms: pairs of colliding atoms interact with one or two laser fields to produce a purely long range {sup 4}He{sub 2}(2{sup 3}S{sub 1}-2{sup 3}P{sub 0}) molecule, or a {sup 4}He{sub 2}(2{sup 3}S{sub 1}-2{sup 3}S{sub 1}) long range molecule. Light shifts in one photon photo-association spectra are measured and studied as a function of the laser polarization and intensity, and the vibrational state of the excited molecule. They result from the light-induced coupling between the excited molecule, and bound and scattering states of the interaction between two metastable atoms. Their analysis leads to the determination of the scattering length a = (7.2 {+-} 0.6) ruling collisions between spin polarized atoms. The two photon photo-association spectra show evidence of the production of polarized, long-range {sup 4}He{sub 2}(2{sup 3}S{sub 1}-2{sup 3}S{sub 1}) molecules. They are said to be exotic as they are made of two metastable atoms, each one carrying a enough energy to ionize the other. The corresponding lineshapes are calculated and decomposed in sums and products of Breit-Wigner and Fano profiles associated to one and two photon processes. The experimental spectra are fit, and an intrinsic lifetime {tau} = (1.4 {+-} 0.3) {mu}s is deduced. It is checked whether this lifetime could be limited by spin-dipole induced Penning autoionization. This interpretation requires that there is a quasi-bound state close to the dissociation threshold in the singlet interaction potential between metastable helium atoms for the theory to match the experiment. (author)

Prenatal typing of Rh and Kell blood group system antigens: the edge of a watershed.

Science.gov (United States)

van der Schoot, C Ellen; Tax, G H Martine; Rijnders, Robbert J P; de Haas, Masja; Christiaens, Godelieve C M L

2003-01-01

Knowledge of the molecular basis of the blood group systems has enabled the development of assays for blood group genotyping. At this time, polymerase chain reaction (PCR)-based assays validated on fetal material obtained by invasive means (chorionic villus sampling or amniocentesis) are available for all clinically relevant fetal blood groups, However, only Rh typing (D, C, c, E, and e) and K1 genotyping assays are discussed in this review. Importantly, one must remember that results of genotyping assays will not always be concordant with serological typing. Thus, the RhD genotyping assays have to be modified in response to increased understanding of the molecular biology of this blood group system. RhD typing assays should produce negative results when tested on the black RhD-negative RHD alleles, RHDpsi and r's. PCR-based assays can be used to determine paternal zygosity. For RhD zygosity testing, the real-time quantitative PCR approach and the direct detection of the hybrid Rhesus box, which is the result of the deletion of the RHD gene are available. Recently, methods for noninvasive prenatal genotyping have been investigated. The use of fetal cells circulating in the maternal circulation has been explored; however, the scarcity of circulating fetal cells has limited the use of this approach. More promising are the results obtained with RhD typing assays with cell-free fetal DNA, which is present in the maternal circulation in a concentration of 25 genomic equivalents per milliliter of maternal blood in early pregnancy increasing to 100 copies per milliliter in the third trimester, which is cleared from the circulation within a few hours of delivery. The positive predictive value of this approach is virtually 100%, but false-negative results are (infrequently) encountered. Therefore, this assay can at present only be used for screening of RhD-negative women to make the use of antenatal prophylaxis more targeted and hence more cost-effective. For the clinical

Improved Dye Stability in Single-Molecule Fluorescence Experiments

Science.gov (United States)

EcheverrÍa Aitken, Colin; Marshall, R. Andrew; Pugi, Joseph D.

Complex biological systems challenge existing single-molecule methods. In particular, dye stability limits observation time in singlemolecule fluorescence applications. Current approaches to improving dye performance involve the addition of enzymatic oxygen scavenging systems and small molecule additives. We present an enzymatic oxygen scavenging system that improves dye stability in single-molecule experiments. Compared to the currently-employed glucose-oxidase/catalase system, the protocatechuate-3,4-dioxygenase system achieves lower dissolved oxygen concentration and stabilizes single Cy3, Cy5, and Alexa488 fluorophores. Moreover, this system possesses none of the limitations associated with the glucose oxidase/catalase system. We also tested the effects of small molecule additives in this system. Biological reducing agents significantly destabilize the Cy5 fluorophore as a function of reducing potential. In contrast, anti-oxidants stabilize the Cy3 and Alexa488 fluorophores. We recommend use of the protocatechuate-3,4,-dioxygenase system with antioxidant additives, and in the absence of biological reducing agents. This system should have wide application to single-molecule fluorescence experiments.

PHYSICAL-CONSTRAINT-PRESERVING CENTRAL DISCONTINUOUS GALERKIN METHODS FOR SPECIAL RELATIVISTIC HYDRODYNAMICS WITH A GENERAL EQUATION OF STATE

Energy Technology Data Exchange (ETDEWEB)

Wu, Kailiang [School of Mathematical Sciences, Peking University, Beijing 100871 (China); Tang, Huazhong, E-mail: wukl@pku.edu.cn, E-mail: hztang@math.pku.edu.cn [HEDPS, CAPT and LMAM, School of Mathematical Sciences, Peking University, Beijing 100871 (China)

2017-01-01

The ideal gas equation of state (EOS) with a constant adiabatic index is a poor approximation for most relativistic astrophysical flows, although it is commonly used in relativistic hydrodynamics (RHD). This paper develops high-order accurate, physical-constraints-preserving (PCP), central, discontinuous Galerkin (DG) methods for the one- and two-dimensional special RHD equations with a general EOS. It is built on our theoretical analysis of the admissible states for RHD and the PCP limiting procedure that enforce the admissibility of central DG solutions. The convexity, scaling invariance, orthogonal invariance, and Lax–Friedrichs splitting property of the admissible state set are first proved with the aid of its equivalent form. Then, the high-order central DG methods with the PCP limiting procedure and strong stability-preserving time discretization are proved, to preserve the positivity of the density, pressure, specific internal energy, and the bound of the fluid velocity, maintain high-order accuracy, and be L {sup 1}-stable. The accuracy, robustness, and effectiveness of the proposed methods are demonstrated by several 1D and 2D numerical examples involving large Lorentz factor, strong discontinuities, or low density/pressure, etc.

Isotope separation using vibrationally excited molecules

International Nuclear Information System (INIS)

Woodroffe, J.A.; Keck, J.C.

1979-01-01

Vibrational excitation of molecules having components of a selected isotope type is used to produce a conversion from vibrational to translational excitation of the molecules by collision with the molecules of a heavy carrier gas. The resulting difference in translaton between the molecules of the selected isotope type and all other molecules of the same compound permits their separate collection. When applied to uranium enrichment, a subsonic cryogenic flow of molecules of uranium hexafluoride in combination with an argon carrier gas is directed through a cooled chamber that is illuminated by laser radiaton tuned to vibrationally excite the uranium hexafluoride molecules of a specific uranium isotope. The excited molecules collide with carrier gas molecules, causing a conversion of the excitation energy into a translation of the excited molecule, which results in a higher thermal energy or diffusivity than that of the other uranium hexafluoride molecules. The flowing molecules including the excited molecules directly enter a set of cryogenically cooled channels. The higher thermal velocity of the excited molecules increases the probability of their striking a collector surface. The molecules which strike this surface immediately condense. After a predetermined thickness of molecules is collected on the surface, the flow of uranium hexafluoride is interrupted and the chamber heated to the point of vaporization of the collected hexafluoride, permitting its removal. (LL)

Caffeine and REM sleep deprivation: Effect on basal levels of signaling molecules in area CA1.

Science.gov (United States)

Alkadhi, Karim A; Alhaider, Ibrahim A

2016-03-01

We have investigated the neuroprotective effect of chronic caffeine treatment on basal levels of memory-related signaling molecules in area CA1 of sleep-deprived rats. Animals in the caffeine groups were treated with caffeine in drinking water (0.3g/l) for four weeks before they were REM sleep-deprived for 24h in the Modified Multiple Platforms paradigm. Western blot analysis of basal protein levels of plasticity- and memory-related signaling molecules in hippocampal area CA1 showed significant down regulation of the basal levels of phosphorylated- and total-CaMKII, phosphorylated- and total-CREB as well as those of BDNF and CaMKIV in sleep deprived rats. All these changes were completely prevented in rats that chronically consumed caffeine. The present findings suggest an important neuroprotective property of caffeine in sleep deprivation. Copyright © 2016 Elsevier Inc. All rights reserved.

Calculations of relativistic effects in atoms and molecules from the Schroedinger wave function

International Nuclear Information System (INIS)

Detrich, J.H.; Roothaan, C.C.J.

1981-01-01

The traditional method for dealing with relativistic effects in atoms and molecules consists of a somewhat heuristic combination of quantum electrodynamics and a many-electron quantum mechanics generalized from the one-electron Dirac theory. On the whole, results calculated from this theory agree with experimental data. Nevertheless, the theory is by no means entirely satisfactory; in its development, certain ambiguities and divergencies must be resolved by somewhat arbitrary and/or questionable means. This paper illuminates - and sidesteps - some of the more questionable aspects of the traditional method, by reformulating electromagnetic interactions between particles in a different way

Effect of osteogenesis imperfecta mutations in tropocollagen molecule on strength of biomimetic tropocollagen-hydroxyapatite nanocomposites

Science.gov (United States)

Dubey, Devendra K.; Tomar, Vikas

2010-01-01

Osteogenesis Imperfecta (OI) is a genetic disorder that affects cellular synthesis of Type-I collagen fibrils and causes extreme bone fragility. This study reports the effects of OI mutations in Tropocollagen (TC) molecules on strength of model Tropocollagen-Hydroxyapatite biomaterials with two different mineral [hydroxyapatite (HAP)] distributions using three dimensional atomistic simulations. Results show that the effect of TC mutations on the strength of TC-HAP biomaterials is insignificant. Instead, change in mineral distribution showed significant impact on the overall strength of TC-HAP biomaterials. Study suggests that TC mutations manifest themselves by changing the mineral distribution during hydroxyapatite growth and nucleation period.

Dynamical spin accumulation in large-spin magnetic molecules

Science.gov (United States)

Płomińska, Anna; Weymann, Ireneusz; Misiorny, Maciej

2018-01-01

The frequency-dependent transport through a nanodevice containing a large-spin magnetic molecule is studied theoretically in the Kondo regime. Specifically, the effect of magnetic anisotropy on dynamical spin accumulation is of primary interest. Such accumulation arises due to finite components of frequency-dependent conductance that are off diagonal in spin. Here, employing the Kubo formalism and the numerical renormalization group method, we demonstrate that the dynamical transport properties strongly depend on the relative orientation of spin moments in electrodes of the device, as well as on intrinsic parameters of the molecule. In particular, the effect of dynamical spin accumulation is found to be greatly affected by the type of magnetic anisotropy exhibited by the molecule, and it develops for frequencies corresponding to the Kondo temperature. For the parallel magnetic configuration of the device, the presence of dynamical spin accumulation is conditioned by the interplay of ferromagnetic-lead-induced exchange field and the Kondo correlations.

The effect of uniform capture molecule orientation on biosensor sensitivity : dependence on analyte properties

NARCIS (Netherlands)

Trilling, A.K.; Harmsen, M.M.; Ruigrok, V.J.; Zuilhof, H.; Beekwilder, J.

2013-01-01

Uniform orientation of capture molecules on biosensors has been reported to increase sensitivity. Here it is investigated which analyte properties contribute to sensitivity by orientation. Orientation of capture molecules on biosensors was investigated using variable domains of llama heavy-chain

Effect of charged and excited states on the decomposition of 1,1-diamino-2,2-dinitroethylene molecules

International Nuclear Information System (INIS)

Kimmel, Anna V.; Sushko, Peter V.; Shluger, Alexander L.; Kuklja, Maija M.

2007-01-01

The authors have calculated the electronic structure of individual 1,1-diamino-2,2-dinitroethylene molecules (FOX-7) in the gas phase by means of density functional theory with the hybrid B3LYP functional and 6-31+G(d,p) basis set and considered their dissociation pathways. Positively and negatively charged states as well as the lowest excited states of the molecule were simulated. They found that charging and excitation can not only reduce the activation barriers for decomposition reactions but also change the dominating chemistry from endo- to exothermic type. In particular, they found that there are two competing primary initiation mechanisms of FOX-7 decomposition: C-NO 2 bond fission and C-NO 2 to CONO isomerization. Electronic excitation or charging of FOX-7 disfavors CONO formation and, thus, terminates this channel of decomposition. However, if CONO is formed from the neutral FOX-7 molecule, charge trapping and/or excitation results in spontaneous splitting of an NO group accompanied by the energy release. Intramolecular hydrogen transfer is found to be a rare event in FOX-7 unless free electrons are available in the vicinity of the molecule, in which case HONO formation is a feasible exothermic reaction with a relatively low energy barrier. The effect of charged and excited states on other possible reactions is also studied. Implications of the obtained results to FOX-7 decomposition in condensed state are discussed

Single-Molecule Spectroscopy

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 20; Issue 2. Single-Molecule Spectroscopy: Every Molecule is Different! Kankan Bhattacharyya. General Article Volume 20 Issue 2 February 2015 pp 151-164. Fulltext. Click here to view fulltext PDF. Permanent link:

Desorption of large organic molecules by laser-induced plasmon excitation

International Nuclear Information System (INIS)

Lee, I.; Callcott, T.A.

1991-01-01

Ejection of large organic molecules from surfaces by laser-induced electronic-excited desorption has attracted considerable interest in recent years. In addition to the importance of this effect for fundamental investigations of the ejection process, this desorption technique has been applied to the study of large, fragile molecules by mass spectrometry. In this paper, we present a new method to induce electronic excitation on the metal surface for the desorption of large organic molecules. 3 refs., 3 figs

Fabrication and study of hybrid molecule/superconductor assemblies

International Nuclear Information System (INIS)

McDevitt, J.T.; Haupt, S.G.; Jurbergs, D.; Riley, D.R.; Zhao, J.; Zhou, J.P.; Lo, K.; Grassi, J.; Jones, C.

1994-01-01

The fabrication of electronic devices from molecular materials has attracted much attention recently. Schottky diodes, molecular transistors, metal-insulator-semiconductor diodes, MIS field effect transistors and light emitting diodes have all been prepared utilizing such substances. The active elements in these devices have been constructed by depositing the molecular phase onto the surface of a metal, semiconductor or insulating substrate. With the recent discovery of high temperature superconductivity, new opportunities now exist for the study of molecule/superconductor interactions as well as for the construction of novel hybrid molecule/superconductor devices. In this paper, methods for preparing the first two classes of composite molecule/superconductor devices are reported. Consequently, light sensors based on organic dye-coated superconductor junctions as well as molecular switches fashioned from organic conductive polymer-coated superconductor microbridges are discussed. Moreover, the initial results related to the study of molecule/superconductor energy and electron transfer phenomena are reported

Ion-Molecule Reaction Dynamics.

Science.gov (United States)

Meyer, Jennifer; Wester, Roland

2017-05-05

We review the recent advances in the investigation of the dynamics of ion-molecule reactions. During the past decade, the combination of single-collision experiments in crossed ion and neutral beams with the velocity map ion imaging detection technique has enabled a wealth of studies on ion-molecule reactions. These methods, in combination with chemical dynamics simulations, have uncovered new and unexpected reaction mechanisms, such as the roundabout mechanism and the subtle influence of the leaving group in anion-molecule nucleophilic substitution reactions. For this important class of reactions, as well as for many fundamental cation-molecule reactions, the information obtained with crossed-beam imaging is discussed. The first steps toward understanding micro-solvation of ion-molecule reaction dynamics are presented. We conclude with the presentation of several interesting directions for future research.

Copy-Number Disorders Are a Common Cause of Congenital Kidney Malformations

Science.gov (United States)

Sanna-Cherchi, Simone; Kiryluk, Krzysztof; Burgess, Katelyn E.; Bodria, Monica; Sampson, Matthew G.; Hadley, Dexter; Nees, Shannon N.; Verbitsky, Miguel; Perry, Brittany J.; Sterken, Roel; Lozanovski, Vladimir J.; Materna-Kiryluk, Anna; Barlassina, Cristina; Kini, Akshata; Corbani, Valentina; Carrea, Alba; Somenzi, Danio; Murtas, Corrado; Ristoska-Bojkovska, Nadica; Izzi, Claudia; Bianco, Beatrice; Zaniew, Marcin; Flogelova, Hana; Weng, Patricia L.; Kacak, Nilgun; Giberti, Stefania; Gigante, Maddalena; Arapovic, Adela; Drnasin, Kristina; Caridi, Gianluca; Curioni, Simona; Allegri, Franca; Ammenti, Anita; Ferretti, Stefania; Goj, Vinicio; Bernardo, Luca; Jobanputra, Vaidehi; Chung, Wendy K.; Lifton, Richard P.; Sanders, Stephan; State, Matthew; Clark, Lorraine N.; Saraga, Marijan; Padmanabhan, Sandosh; Dominiczak, Anna F.; Foroud, Tatiana; Gesualdo, Loreto; Gucev, Zoran; Allegri, Landino; Latos-Bielenska, Anna; Cusi, Daniele; Scolari, Francesco; Tasic, Velibor; Hakonarson, Hakon; Ghiggeri, Gian Marco; Gharavi, Ali G.

2012-01-01

We examined the burden of large, rare, copy-number variants (CNVs) in 192 individuals with renal hypodysplasia (RHD) and replicated findings in 330 RHD cases from two independent cohorts. CNV distribution was significantly skewed toward larger gene-disrupting events in RHD cases compared to 4,733 ethnicity-matched controls (p = 4.8 × 10−11). This excess was attributable to known and novel (i.e., not present in any database or in the literature) genomic disorders. All together, 55/522 (10.5%) RHD cases harbored 34 distinct known genomic disorders, which were detected in only 0.2% of 13,839 population controls (p = 1.2 × 10−58). Another 32 (6.1%) RHD cases harbored large gene-disrupting CNVs that were absent from or extremely rare in the 13,839 population controls, identifying 38 potential novel or rare genomic disorders for this trait. Deletions at the HNF1B locus and the DiGeorge/velocardiofacial locus were most frequent. However, the majority of disorders were detected in a single individual. Genomic disorders were detected in 22.5% of individuals with multiple malformations and 14.5% of individuals with isolated urinary-tract defects; 14 individuals harbored two or more diagnostic or rare CNVs. Strikingly, the majority of the known CNV disorders detected in the RHD cohort have previous associations with developmental delay or neuropsychiatric diseases. Up to 16.6% of individuals with kidney malformations had a molecular diagnosis attributable to a copy-number disorder, suggesting kidney malformations as a sentinel manifestation of pathogenic genomic imbalances. A search for pathogenic CNVs should be considered in this population for the diagnosis of their specific genomic disorders and for the evaluation of the potential for developmental delay. PMID:23159250

Ambipolar Small-Molecule:Polymer Blend Semiconductors for Solution-Processable Organic Field-Effect Transistors.

Science.gov (United States)

Kang, Minji; Hwang, Hansu; Park, Won-Tae; Khim, Dongyoon; Yeo, Jun-Seok; Kim, Yunseul; Kim, Yeon-Ju; Noh, Yong-Young; Kim, Dong-Yu

2017-01-25

We report on the fabrication of an organic thin-film semiconductor formed using a blend solution of soluble ambipolar small molecules and an insulating polymer binder that exhibits vertical phase separation and uniform film formation. The semiconductor thin films are produced in a single step from a mixture containing a small molecular semiconductor, namely, quinoidal biselenophene (QBS), and a binder polymer, namely, poly(2-vinylnaphthalene) (PVN). Organic field-effect transistors (OFETs) based on QBS/PVN blend semiconductor are then assembled using top-gate/bottom-contact device configuration, which achieve almost four times higher mobility than the neat QBS semiconductor. Depth profile via secondary ion mass spectrometry and atomic force microscopy images indicate that the QBS domains in the films made from the blend are evenly distributed with a smooth morphology at the bottom of the PVN layer. Bias stress test and variable-temperature measurements on QBS-based OFETs reveal that the QBS/PVN blend semiconductor remarkably reduces the number of trap sites at the gate dielectric/semiconductor interface and the activation energy in the transistor channel. This work provides a one-step solution processing technique, which makes use of soluble ambipolar small molecules to form a thin-film semiconductor for application in high-performance OFETs.

Electron Accumulative Molecules.

Science.gov (United States)

Buades, Ana B; Sanchez Arderiu, Víctor; Olid-Britos, David; Viñas, Clara; Sillanpää, Reijo; Haukka, Matti; Fontrodona, Xavier; Paradinas, Markos; Ocal, Carmen; Teixidor, Francesc

2018-02-28

With the goal to produce molecules with high electron accepting capacity and low reorganization energy upon gaining one or more electrons, a synthesis procedure leading to the formation of a B-N(aromatic) bond in a cluster has been developed. The research was focused on the development of a molecular structure able to accept and release a specific number of electrons without decomposing or change in its structural arrangement. The synthetic procedure consists of a parallel decomposition reaction to generate a reactive electrophile and a synthesis reaction to generate the B-N(aromatic) bond. This procedure has paved the way to produce the metallacarboranylviologen [M(C 2 B 9 H 11 )(C 2 B 9 H 10 )-NC 5 H 4 -C 5 H 4 N-M'(C 2 B 9 H 11 )(C 2 B 9 H 10 )] (M = M' = Co, Fe and M = Co and M' = Fe) and semi(metallacarboranyl)viologen [3,3'-M(8-(NC 5 H 4 -C 5 H 4 N-1,2-C 2 B 9 H 10 )(1',2'-C 2 B 9 H 11 )] (M = Co, Fe) electron cumulative molecules. These molecules are able to accept up to five electrons and to donate one in single electron steps at accessible potentials and in a reversible way. By targeted synthesis and corresponding electrochemical tests each electron transfer (ET) step has been assigned to specific fragments of the molecules. The molecules have been carefully characterized, and the electronic communication between both metal centers (when this situation applies) has been definitely observed through the coplanarity of both pyridine fragments. The structural characteristics of these molecules imply a low reorganization energy that is a necessary requirement for low energy ET processes. This makes them electronically comparable to fullerenes, but on their side, they have a wide range of possible solvents. The ET from one molecule to another has been clearly demonstrated as well as their self-organizing capacity. We consider that these molecules, thanks to their easy synthesis, ET, self-organizing capacity, wide range of solubility, and easy processability, can

Adsorption of methanol molecule on graphene: Experimental results and first-principles calculations

Science.gov (United States)

Zhao, X. W.; Tian, Y. L.; Yue, W. W.; Chen, M. N.; Hu, G. C.; Ren, J. F.; Yuan, X. B.

2018-04-01

Adsorption properties of methanol molecule on graphene surface are studied both theoretically and experimentally. The adsorption geometrical structures, adsorption energies, band structures, density of states and the effective masses are obtained by means of first-principles calculations. It is found that the electronic characteristics and conductivity of graphene are sensitive to the methanol molecule adsorption. After adsorption of methanol molecule, bandgap appears. With the increasing of the adsorption distance, the bandgap, adsorption energy and effective mass of the adsorption system decreased, hence the resistivity of the system decreases gradually, these results are consistent with the experimental results. All these calculations and experiments indicate that the graphene-based sensors have a wide range of applications in detecting particular molecules.

Higher-Dimensional Origin of Heavy Sneutrino Domination and Low-Scale Leptogenesis

CERN Document Server

Hebecker, A; Yanagida, T

2003-01-01

If the expectation value of the right-handed (rhd) sneutrino comes to dominate the universe, its decay naturally leads to successful leptogenesis, as well as significant dilution of dangerous inflationary relics, such as the gravitino. The resulting baryon asymmetry is independent of other cosmological initial conditions. This attractive variant of leptogenesis requires at least one of the rhd neutrinos to have small Yukawa coupling and to have mass ~ 10^6 GeV, much smaller than the grand unified (GUT) scale. We show that these features naturally arise in the context of independently motivated and successful 5d orbifold GUTs with inverse-GUT-scale-sized extra dimensions. Rhd neutrinos are realized as bulk fields N_i with 5d bulk masses, while Yukawa couplings and lepton-number-violating masses for the N_i are localized at the SM boundary. The exponential suppression of the would-be N_i zero-modes leads to the desired small 4d Yukawa couplings and small masses for the rhd neutrino states. The see-saw predictio...

Single molecule conductance

NARCIS (Netherlands)

Willems, R.

2008-01-01

This thesis represents an excursion into the world of molecular electronics, i.e. the field of research trying to use individual (organic) molecules as electronic components; in this work various experimental methods have been explored to connect individual molecules to metallic contacts and

Small Molecule Agonists of Cell Adhesion Molecule L1 Mimic L1 Functions In Vivo.

Science.gov (United States)

Kataria, Hardeep; Lutz, David; Chaudhary, Harshita; Schachner, Melitta; Loers, Gabriele

2016-09-01

Lack of permissive mechanisms and abundance of inhibitory molecules in the lesioned central nervous system of adult mammals contribute to the failure of functional recovery after injury, leading to severe disabilities in motor functions and pain. Peripheral nerve injury impairs motor, sensory, and autonomic functions, particularly in cases where nerve gaps are large and chronic nerve injury ensues. Previous studies have indicated that the neural cell adhesion molecule L1 constitutes a viable target to promote regeneration after acute injury. We screened libraries of known drugs for small molecule agonists of L1 and evaluated the effect of hit compounds in cell-based assays in vitro and in mice after femoral nerve and spinal cord injuries in vivo. We identified eight small molecule L1 agonists and showed in cell-based assays that they stimulate neuronal survival, neuronal migration, and neurite outgrowth and enhance Schwann cell proliferation and migration and myelination of neurons in an L1-dependent manner. In a femoral nerve injury mouse model, enhanced functional regeneration and remyelination after application of the L1 agonists were observed. In a spinal cord injury mouse model, L1 agonists improved recovery of motor functions, being paralleled by enhanced remyelination, neuronal survival, and monoaminergic innervation, reduced astrogliosis, and activation of microglia. Together, these findings suggest that application of small organic compounds that bind to L1 and stimulate the beneficial homophilic L1 functions may prove to be a valuable addition to treatments of nervous system injuries.

Real-time single-molecule imaging of quantum interference.

Science.gov (United States)

Juffmann, Thomas; Milic, Adriana; Müllneritsch, Michael; Asenbaum, Peter; Tsukernik, Alexander; Tüxen, Jens; Mayor, Marcel; Cheshnovsky, Ori; Arndt, Markus

2012-03-25

The observation of interference patterns in double-slit experiments with massive particles is generally regarded as the ultimate demonstration of the quantum nature of these objects. Such matter-wave interference has been observed for electrons, neutrons, atoms and molecules and, in contrast to classical physics, quantum interference can be observed when single particles arrive at the detector one by one. The build-up of such patterns in experiments with electrons has been described as the "most beautiful experiment in physics". Here, we show how a combination of nanofabrication and nano-imaging allows us to record the full two-dimensional build-up of quantum interference patterns in real time for phthalocyanine molecules and for derivatives of phthalocyanine molecules, which have masses of 514 AMU and 1,298 AMU respectively. A laser-controlled micro-evaporation source was used to produce a beam of molecules with the required intensity and coherence, and the gratings were machined in 10-nm-thick silicon nitride membranes to reduce the effect of van der Waals forces. Wide-field fluorescence microscopy detected the position of each molecule with an accuracy of 10 nm and revealed the build-up of a deterministic ensemble interference pattern from single molecules that arrived stochastically at the detector. In addition to providing this particularly clear demonstration of wave-particle duality, our approach could also be used to study larger molecules and explore the boundary between quantum and classical physics.

Small molecules enhance CRISPR genome editing in pluripotent stem cells.

Science.gov (United States)

Yu, Chen; Liu, Yanxia; Ma, Tianhua; Liu, Kai; Xu, Shaohua; Zhang, Yu; Liu, Honglei; La Russa, Marie; Xie, Min; Ding, Sheng; Qi, Lei S

2015-02-05

The bacterial CRISPR-Cas9 system has emerged as an effective tool for sequence-specific gene knockout through non-homologous end joining (NHEJ), but it remains inefficient for precise editing of genome sequences. Here we develop a reporter-based screening approach for high-throughput identification of chemical compounds that can modulate precise genome editing through homology-directed repair (HDR). Using our screening method, we have identified small molecules that can enhance CRISPR-mediated HDR efficiency, 3-fold for large fragment insertions and 9-fold for point mutations. Interestingly, we have also observed that a small molecule that inhibits HDR can enhance frame shift insertion and deletion (indel) mutations mediated by NHEJ. The identified small molecules function robustly in diverse cell types with minimal toxicity. The use of small molecules provides a simple and effective strategy to enhance precise genome engineering applications and facilitates the study of DNA repair mechanisms in mammalian cells. Copyright © 2015 Elsevier Inc. All rights reserved.

Gamma radiation-induced structural changes in triglyceride molecules in pork fat

International Nuclear Information System (INIS)

Salkova, Z.; Koman, V.

1976-01-01

In the structure of associated and individual triglyceride pork fat molecules, some changes take place under the effect of ionizing radiation. Due to the irradiation of the fat the amount of the di- and tri-unsaturated (UUU, UUS, USU) triglyceride molecules decreases. The occurrence of the unsatured fatty acids on sites 1,3 decreases and the percentage of the individual triglyceride molecules having on their extreme sites C-1,3 unsaturated fatty acids decreases in all combinations. It can be assumed that hydrogenation and pre-esterification occurs in the triglyceride molecules. (author)

Rheumatic fever and rheumatic heart disease in Bangladesh: A review

Science.gov (United States)

Islam, A.K.M. Monwarul; Majumder, A.A.S.

2016-01-01

Rheumatic fever (RF) and rheumatic heart disease (RHD) are the most-common cardiovascular disease in young people aged diseases over the last century. In concert with the progresses in socioeconomic indicators, advances in health sectors, improved public awareness, and antibiotic prophylaxis, acute RF came into control. However, chronic RHD continues to be prevalent, and the actual disease burden may be much higher. RHD predominantly affects the young adults, seriously incapacitates them, follows a protracted course, gets complicated because of delayed diagnosis and is sometimes maltreated. The treatment is often palliative and expensive. Large-scale epidemiological and clinical researches are needed to formulate evidence-based national policy to tackle this important public health issue in future. PMID:26896274

Discriminating Intercalative Effects of Threading Intercalator Nogalamycin, from Classical Intercalator Daunomycin, Using Single Molecule Atomic Force Spectroscopy.

Directory of Open Access Journals (Sweden)

T Banerjee

Full Text Available DNA threading intercalators are a unique class of intercalating agents, albeit little biophysical information is available on their intercalative actions. Herein, the intercalative effects of nogalamycin, which is a naturally-occurring DNA threading intercalator, have been investigated by high-resolution atomic force microscopy (AFM and spectroscopy (AFS. The results have been compared with those of the well-known chemotherapeutic drug daunomycin, which is a non-threading classical intercalator bearing structural similarity to nogalamycin. A comparative AFM assessment revealed a greater increase in DNA contour length over the entire incubation period of 48 h for nogalamycin treatment, whereas the contour length increase manifested faster in case of daunomycin. The elastic response of single DNA molecules to an externally applied force was investigated by the single molecule AFS approach. Characteristic mechanical fingerprints in the overstretching behaviour clearly distinguished the nogalamycin/daunomycin-treated dsDNA from untreated dsDNA-the former appearing less elastic than the latter, and the nogalamycin-treated DNA distinguished from the daunomycin-treated DNA-the classically intercalated dsDNA appearing the least elastic. A single molecule AFS-based discrimination of threading intercalation from the classical type is being reported for the first time.

Discriminating Intercalative Effects of Threading Intercalator Nogalamycin, from Classical Intercalator Daunomycin, Using Single Molecule Atomic Force Spectroscopy.

Science.gov (United States)

Banerjee, T; Banerjee, S; Sett, S; Ghosh, S; Rakshit, T; Mukhopadhyay, R

2016-01-01

DNA threading intercalators are a unique class of intercalating agents, albeit little biophysical information is available on their intercalative actions. Herein, the intercalative effects of nogalamycin, which is a naturally-occurring DNA threading intercalator, have been investigated by high-resolution atomic force microscopy (AFM) and spectroscopy (AFS). The results have been compared with those of the well-known chemotherapeutic drug daunomycin, which is a non-threading classical intercalator bearing structural similarity to nogalamycin. A comparative AFM assessment revealed a greater increase in DNA contour length over the entire incubation period of 48 h for nogalamycin treatment, whereas the contour length increase manifested faster in case of daunomycin. The elastic response of single DNA molecules to an externally applied force was investigated by the single molecule AFS approach. Characteristic mechanical fingerprints in the overstretching behaviour clearly distinguished the nogalamycin/daunomycin-treated dsDNA from untreated dsDNA-the former appearing less elastic than the latter, and the nogalamycin-treated DNA distinguished from the daunomycin-treated DNA-the classically intercalated dsDNA appearing the least elastic. A single molecule AFS-based discrimination of threading intercalation from the classical type is being reported for the first time.

The Molecule Cloud - compact visualization of large collections of molecules

Directory of Open Access Journals (Sweden)

Ertl Peter

2012-07-01

Full Text Available Abstract Background Analysis and visualization of large collections of molecules is one of the most frequent challenges cheminformatics experts in pharmaceutical industry are facing. Various sophisticated methods are available to perform this task, including clustering, dimensionality reduction or scaffold frequency analysis. In any case, however, viewing and analyzing large tables with molecular structures is necessary. We present a new visualization technique, providing basic information about the composition of molecular data sets at a single glance. Summary A method is presented here allowing visual representation of the most common structural features of chemical databases in a form of a cloud diagram. The frequency of molecules containing particular substructure is indicated by the size of respective structural image. The method is useful to quickly perceive the most prominent structural features present in the data set. This approach was inspired by popular word cloud diagrams that are used to visualize textual information in a compact form. Therefore we call this approach “Molecule Cloud”. The method also supports visualization of additional information, for example biological activity of molecules containing this scaffold or the protein target class typical for particular scaffolds, by color coding. Detailed description of the algorithm is provided, allowing easy implementation of the method by any cheminformatics toolkit. The layout algorithm is available as open source Java code. Conclusions Visualization of large molecular data sets using the Molecule Cloud approach allows scientists to get information about the composition of molecular databases and their most frequent structural features easily. The method may be used in the areas where analysis of large molecular collections is needed, for example processing of high throughput screening results, virtual screening or compound purchasing. Several example visualizations of large

Molecules in strong laser fields. In depth study of H2 molecule

International Nuclear Information System (INIS)

Awasthi, Manohar

2009-01-01

-threshold-ionization peaks is also demonstrated. The CI-TDSE results for H 2 are used for testing the validity of SAE approximation. In strong field physics, there are models based on the SAE approximation. Most popular are the Ammosov-Delone-Krainov (ADK) model, a molecular version of the ADK model called MO-ADK (MO stands for molecular orbital) and the strong field approximation (SFA). The validity of the second method for the solution of TDSE in SAE approximation is investigated by applying it to H 2 molecule where the exact two-electron results were already calculated using CI-TDSE. The SAE method uses density-functional-theory (DFT) for the description of field-free eigenstates and is thus abbreviated as DFT-SAE-TDSE. Since DFT is used for the calculation of field-free states, different functionals were also tested. The validity of MO-ADK model is also investigated. After establishing the DFT-SAE-TDSE method, the first excited state B 1 Σ u + of H 2 is studied over a large range of laser parameters. The effect of the closely lying excited states on ionization and excitation is studied. After successful testing of DFT-SAE-TDSE method on H 2 molecule, the results for larger molecules like N 2 , O 2 and C 2 H 2 in the DFT-SAE framework are presented. (orig.)

Tunnel magnetoresistance of magnetic molecules with spin-vibron coupling

Directory of Open Access Journals (Sweden)

Ahmed Kenawy

2017-05-01

Full Text Available The effect of molecular vibrations on the tunnel magnetoresistance (TMR of a magnetic tunnel junction with a single spin-anisotropic molecule interconnecting its electrodes is investigated theoretically. We demonstrate that if these vibrations couple at the same time to the charge of tunneling electrons and to the spin of the molecule, the spin anisotropy of such a molecule becomes enhanced. This has, in turn, a profound impact on the TMR of such a device showing that molecular vibrations lead to a significant change of spin-polarized transport, differing for the parallel and antiparallel magnetic configuration of the junction.

The interaction of low-energy electrons with fructose molecules

Science.gov (United States)

Chernyshova, I. V.; Kontrosh, E. E.; Markush, P. P.; Shpenik, O. B.

2017-11-01

Using a hypocycloidal electronic spectrometer, the interactions of low energy electrons (0-8.50 eV) with fructose molecules, namely, electron scattering and dissociative attachment, are studied. The results of these studies showed that the fragmentation of fructose molecules occurs effectively even at an electron energy close to zero. In the total electron-scattering cross section by molecules, resonance features (at energies 3.10 and 5.00 eV) were first observed near the formation thresholds of light ion fragments OH- and H-. The correlation of the features observed in the cross sections of electron scattering and dissociative attachment is analyzed.

Dust-forming molecules in VY Canis Majoris (and Betelgeuse)

Science.gov (United States)

Kamiński, T.; Gottlieb, C. A.; Schmidt, M. R.; Patel, N. A.; Young, K. H.; Menten, K. M.; Brünken, S.; Müller, H. S. P.; Winters, J. M.; McCarthy, M. C.

2013-05-01

The formation of inorganic dust in circumstellar environments of evolved stars is poorly understood. Spectra of molecules thought to be most important for the nucleation, i.e. AlO, TiO, and TiO2, have been recently detected in the red supergiant VY CMa. These molecules are effectively formed in VY CMa and the observations suggest that non-equilibrium chemistry must be involved in their formation and nucleation into dust. In addition to exploring the recent observations of VY CMa, we briefly discuss the possibility of detecting these molecules in the "dust-poor" circumstellar environment of Betelgeuse.

The worldwide epidemiology of acute rheumatic fever and rheumatic heart disease

Science.gov (United States)

Seckeler, Michael D; Hoke, Tracey R

2011-01-01

Acute rheumatic fever (ARF) and rheumatic heart disease (RHD) are significant public health concerns around the world. Despite decreasing incidence, there is still a significant disease burden, especially in developing nations. This review provides background on the history of ARF, its pathology and treatment, and the current reported worldwide incidence of ARF and prevalence of RHD. PMID:21386976

Challenges for single molecule electronic devices with nanographene and organic molecules. Do single molecules offer potential as elements of electronic devices in the next generation?

Science.gov (United States)

Enoki, Toshiaki; Kiguchi, Manabu

2018-03-01

Interest in utilizing organic molecules to fabricate electronic materials has existed ever since organic (molecular) semiconductors were first discovered in the 1950s. Since then, scientists have devoted serious effort to the creation of various molecule-based electronic systems, such as molecular metals and molecular superconductors. Single-molecule electronics and the associated basic science have emerged over the past two decades and provided hope for the development of highly integrated molecule-based electronic devices in the future (after the Si-based technology era has ended). Here, nanographenes (nano-sized graphene) with atomically precise structures are among the most promising molecules that can be utilized for electronic/spintronic devices. To manipulate single small molecules for an electronic device, a single molecular junction has been developed. It is a powerful tool that allows even small molecules to be utilized. External electric, magnetic, chemical, and mechanical perturbations can change the physical and chemical properties of molecules in a way that is different from bulk materials. Therefore, the various functionalities of molecules, along with changes induced by external perturbations, allows us to create electronic devices that we cannot create using current top-down Si-based technology. Future challenges that involve the incorporation of condensed matter physics, quantum chemistry calculations, organic synthetic chemistry, and electronic device engineering are expected to open a new era in single-molecule device electronic technology.

Electron-molecule collisions

CERN Document Server

Takayanagi, Kazuo

1984-01-01

Scattering phenomena play an important role in modern physics. Many significant discoveries have been made through collision experiments. Amongst diverse kinds of collision systems, this book sheds light on the collision of an electron with a molecule. The electron-molecule collision provides a basic scattering problem. It is scattering by a nonspherical, multicentered composite particle with its centers having degrees of freedom of motion. The molecule can even disintegrate, Le., dissociate or ionize into fragments, some or all of which may also be molecules. Although it is a difficult problem, the recent theoretical, experimental, and computational progress has been so significant as to warrant publication of a book that specializes in this field. The progress owes partly to technical develop­ ments in measurements and computations. No less important has been the great and continuing stimulus from such fields of application as astrophysics, the physics of the earth's upper atmosphere, laser physics, radiat...

Preparation of translationally cold neutral molecules.

Science.gov (United States)

Di Domenicantonio, Giulia; Bertsche, Benjamin; Osterwalder, Andreas

2011-01-01

Efforts at EPFL to obtain translationally cold neutral molecules are described. Active deceleration of polar molecules is performed by confining the molecules in moving three-dimensional electrostatic traps, and by appropriately choosing the velocity of those traps. Alternatively, cold molecules can be obtained by velocity filtering. Here, the velocity of the molecules is not changed, but instead the cold molecules are extracted from a thermal sample by using the competition between the electrostatic force and the centrifugal force inside a bent electrostatic guide for polar molecules.

SYSTEMATIC THEORETICAL STUDY ON THE INTERSTELLAR CARBON CHAIN MOLECULES

Energy Technology Data Exchange (ETDEWEB)

Etim, Emmanuel E.; Arunan, Elangannan [Inorganic and Physical Chemistry Department, Indian Institute of Science Bangalore, 560012 (India); Gorai, Prasanta; Das, Ankan [Indian Centre for Space Physics, 43 Chalantika, Garia Station Road, Kolkata 700 084 (India); Chakrabarti, Sandip K., E-mail: ankan.das@gmail.com [Department of Chemical Sciences, Federal University Wukari,  Katsina-Ala Road, P.M.B. 1020 Wukari, Taraba State (Nigeria)

2016-12-01

In an effort to further our interest in understanding the basic chemistry of interstellar molecules, here we carry out an extensive investigation of the stabilities of interstellar carbon chains; C{sub n}, H{sub 2}C{sub n}, HC{sub n}N and C{sub n}X (X = N, O, Si, S, H, P, H{sup −}, N{sup −}). These sets of molecules account for about 20% of all the known interstellar and circumstellar molecules. Their high abundances, therefore, demand serious attention. High-level ab initio quantum chemical calculations are employed to accurately estimate the enthalpy of formation, chemical reactivity indices, global hardness and softness, and other chemical parameters of these molecules. Chemical modeling of the abundances of these molecular species has also been performed. Of the 89 molecules considered from these groups, 47 have been astronomically observed, and these observed molecules are found to be more stable with respect to other members of the group. Of the 47 observed molecules, 60% are odd-numbered carbon chains. Interstellar chemistry is not actually driven by thermodynamics, but it is primarily dependent on various kinetic parameters. However, we found that the detectability of the odd-numbered carbon chains could be correlated due to the fact that they are more stable than the corresponding even-numbered carbon chains. Based on this aspect, the next possible carbon chain molecule for astronomical observation in each group is proposed. The effect of kinetics in the formation of some of these carbon chain molecules is also discussed.

Effects of irradiation on the expression of the adhesion molecules (NCAM, ICAM-1) by glioma cell lines

Energy Technology Data Exchange (ETDEWEB)

Yamanaka, Ryuya; Tanaka, Ryuichi; Yoshida, Seiichi [Niigata Univ. (Japan). Brain Research Inst.

1993-11-01

The expression of the intercellular adhesion molecule-1 (ICAM-1) and neural cell adhesion molecule (NCAM) by glioma cell lines was investigated. The effects of interferon (IFN)-[gamma] or irradiation on the expression was also assessed. Two glioma cell lines showed more than 75% NCAM-positive cells. After treatment with IFN-[gamma] or irradiation, another three cell lines were induced to show more than 50% positive cells. Three glioma cell lines showed more than 50% ICAM-1-positive cells. After treatment with IFN-[gamma], another two cell lines were induced to show more than 50% positive cells. After treatment with irradiation, one more cell line was induced to show more than 50% positive cells. ICAM-1 and NCAM expression by glioma cell lines is susceptible to modulation by IFN-[gamma] or irradiation. (author).

Effects of autoionizing states on two-photon double ionization of the H2 molecule

International Nuclear Information System (INIS)

Guan, Xiaoxu; Bartschat, Klaus; Schneider, Barry I; Koesterke, Lars

2014-01-01

Treating the effects of autoionizing intermediate states on two-photon double ionization (DI) of the H 2 molecule using time-dependent laser pulses is a significant computational challenge. Relatively long exposure times are critical to understanding the dynamics. Using the fixed-nuclei approximation, we demonstrate how the doubly excited states enhance the angle-integrated generalized cross sections in H 2 , and how they affect the angular distribution pattern of the ejected electrons. As the energy approaches the threshold for sequential DI, there is a sharp rise in the cross section due to virtual sequential ionization

Effect of lattice-gas atoms on the adsorption behaviour of thioether molecules.

Science.gov (United States)

Pan, Yi; Yang, Bing; Hulot, Catherine; Blechert, Siegfried; Nilius, Niklas; Freund, Hans-Joachim

2012-08-21

Using STM topographic imaging and spectroscopy, we have investigated the adsorption of two thioether molecules, 1,2-bis(phenylthio)benzene and (bis(3-phenylthio)-phenyl)sulfane, on noble and transition metal surfaces. The two substrates show nearly antipodal behaviour. Whereas complexes with one or two protruding centres are observed on Au(111), only flat and uniform ad-structures are found on NiAl(110). The difference is ascribed to the possibility of the thioethers to form metal-organic complexes by coordinating lattice-gas atoms on the Au(111), while only the pristine molecules adsorb on the alloy surface. The metal coordination in the first case is driven by the formation of strong Au-S bonds and enables the formation of characteristic monomer, dimer and chain-like structures of the thioethers, using the Au atoms as linkers. A similar mechanism is not available on the NiAl, because no lattice gas develops at this surface at room temperature. Our work demonstrates how surface properties, i.e. the availability of mobile ad-species, determine the interaction of organic molecules with metallic substrates.

Adsorption of gas molecules on Ga-doped graphene and effect of applied electric field: A DFT study

Energy Technology Data Exchange (ETDEWEB)

Liang, Xiong-Yi [Department of Physics and Materials Science, City University of Hong Kong, Hong Kong SAR (China); Ding, Ning [Department of Physics and Materials Science, City University of Hong Kong, Hong Kong SAR (China); Key Laboratory for Applied Technology of Sophisticated Analytical Instruments, Shandong Academy of Sciences, Jinan 250014 (China); Ng, Siu-Pang [Department of Physics and Materials Science, City University of Hong Kong, Hong Kong SAR (China); Wu, Chi-Man Lawrence, E-mail: lawrence.wu@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Hong Kong SAR (China); Key Laboratory for Applied Technology of Sophisticated Analytical Instruments, Shandong Academy of Sciences, Jinan 250014 (China)

2017-07-31

Highlights: • H{sub 2}O, NH{sub 3}, CO, NO{sub 2} and NO are physically adsorbed on pristine graphene. • The adsorption energies of all gas molecules on graphene are increased after doping with Ga. • NO{sub 2} shows the strongest affinity to Ga-doped graphene. • The electronic properties and adsorption of NO{sub 2} on graphene and can be effectively tuned using an external electric field. - Abstract: Density functional theory calculations have been carried out to study the adsorption of varous gas molecules (H{sub 2}O, NH{sub 3}, CO, NO{sub 2} and NO) on pristine graphene and Ga-doped graphene in order to explore the feasibility of Ga-doped graphene based gas sensor. For each gas molecule, various adsorption positions and orientations were considered. The most stable configuration was determined and the adsorption energies with van der Waals interactions were calculated. Further, electronic properties such as electron density, density of states, charge transfer and band structure were investigated to understand the mechanism of adsorption. The results showed that the gas molecules studied were only weakly adsorbed on pristine graphene with small adsorption energies. On the other hand, the adsorption energies of all gas molecules on Ga-doped graphene increased by various amounts. Adsorption of gas molecules on Ga-doped graphene can open a relatively large band gap ranging from 0.267 to 0.397 eV. NO{sub 2} was found to be very sensitive to Ga-doped graphene with adsorption energy of −1.928 eV due to strong orbital hybridization and large charge transfer. Furthermore, our study suggests that the affinity and electronic properties of NO{sub 2} on Ga-doped graphene can be dramatically changed by an external electric field. A negative electric field enhances the adsorption of NO{sub 2} on Ga-doped graphene as reflected in the increase in adsorption energy. In contrast, the interaction will be weakened under a positive electric field. The results of the DFT

Adsorption of gas molecules on Ga-doped graphene and effect of applied electric field: A DFT study

International Nuclear Information System (INIS)

Liang, Xiong-Yi; Ding, Ning; Ng, Siu-Pang; Wu, Chi-Man Lawrence

2017-01-01

Highlights: • H_2O, NH_3, CO, NO_2 and NO are physically adsorbed on pristine graphene. • The adsorption energies of all gas molecules on graphene are increased after doping with Ga. • NO_2 shows the strongest affinity to Ga-doped graphene. • The electronic properties and adsorption of NO_2 on graphene and can be effectively tuned using an external electric field. - Abstract: Density functional theory calculations have been carried out to study the adsorption of varous gas molecules (H_2O, NH_3, CO, NO_2 and NO) on pristine graphene and Ga-doped graphene in order to explore the feasibility of Ga-doped graphene based gas sensor. For each gas molecule, various adsorption positions and orientations were considered. The most stable configuration was determined and the adsorption energies with van der Waals interactions were calculated. Further, electronic properties such as electron density, density of states, charge transfer and band structure were investigated to understand the mechanism of adsorption. The results showed that the gas molecules studied were only weakly adsorbed on pristine graphene with small adsorption energies. On the other hand, the adsorption energies of all gas molecules on Ga-doped graphene increased by various amounts. Adsorption of gas molecules on Ga-doped graphene can open a relatively large band gap ranging from 0.267 to 0.397 eV. NO_2 was found to be very sensitive to Ga-doped graphene with adsorption energy of −1.928 eV due to strong orbital hybridization and large charge transfer. Furthermore, our study suggests that the affinity and electronic properties of NO_2 on Ga-doped graphene can be dramatically changed by an external electric field. A negative electric field enhances the adsorption of NO_2 on Ga-doped graphene as reflected in the increase in adsorption energy. In contrast, the interaction will be weakened under a positive electric field. The results of the DFT calculation indicates the potential application of Ga

Single-Molecule Electronics with Cross- Conjugated Molecules: Quantum Interference, IETS and Non-Equilibrium "Temperatures"

DEFF Research Database (Denmark)

Jørgensen, Jacob Lykkebo

Abstract The idea of using single-molecules as components in electronic devices is fas- cinating. For this idea to come into fruition, a number of technical and theo- retical challenges must be overcome. In this PhD thesis, the electron-phonon interaction is studied for a special class of molecules......, which is characterised by destructive quantum interference. The molecules are cross-conjugated, which means that the two parts of the molecules are conjugated to a third part, but not to each other. This gives rise to an anti-resonance in the trans- mission. In the low bias and low temperature regime......-conjugated molecules. We nd that the vibrational modes that would be expected to dominate, following the propensity, rules are very weak. Instead, other modes are found to be the dominant ones. We study this phenomenon for a number of cross-conjugated molecules, and link these ndings to the anti...

Single Molecule Electronics and Devices

Science.gov (United States)

Tsutsui, Makusu; Taniguchi, Masateru

2012-01-01

The manufacture of integrated circuits with single-molecule building blocks is a goal of molecular electronics. While research in the past has been limited to bulk experiments on self-assembled monolayers, advances in technology have now enabled us to fabricate single-molecule junctions. This has led to significant progress in understanding electron transport in molecular systems at the single-molecule level and the concomitant emergence of new device concepts. Here, we review recent developments in this field. We summarize the methods currently used to form metal-molecule-metal structures and some single-molecule techniques essential for characterizing molecular junctions such as inelastic electron tunnelling spectroscopy. We then highlight several important achievements, including demonstration of single-molecule diodes, transistors, and switches that make use of electrical, photo, and mechanical stimulation to control the electron transport. We also discuss intriguing issues to be addressed further in the future such as heat and thermoelectric transport in an individual molecule. PMID:22969345

Interactions between nitrogen molecules and barium atoms on Ru (0001) surface

International Nuclear Information System (INIS)

Zhao Xinxin; Mi Yiming; Xu Hongxia; Wang Lili; Ren Li; Tao Xiangming; Tan Mingqiu

2011-01-01

We had performed first principles calculations on interactions between nitrogen molecules and barium atoms on Ru (0001) surface using density function theory methods. It was shown that effects of barium atoms weakened the bond strength of nitrogen molecules. The bond length of nitrogen molecule increases from 0.113 nm on Ru (001)-N 2 to 0.120 nm on Ru (001)-N 2 /Ba surface. While stretch vibrational frequency of nitrogen molecule decreased from 2222 cm -1 and charge transfer toward nitrogen molecule increased from 0.3 e to 1.1 e. Charge was mainly translated from 6 s orbitals of barium atoms to 4 d orbitals of substrate, which enhanced the hybridization between 4 d and 2 π orbitals and increased the dipole moment of 5 σ and d π orbitals of nitrogen molecule. The molecular dipole moment of nitrogen molecule was increased by -0.136 e Anstrom. It was suggested that barium had some characters to be an electronic promoter on the process of activating nitrogen molecules on Ru (0001) surface. (authors)

Studying small molecule-aptamer interactions using MicroScale Thermophoresis (MST).

Science.gov (United States)

Entzian, Clemens; Schubert, Thomas

2016-03-15

Aptamers are potent and versatile binding molecules recognizing various classes of target molecules. Even challenging targets such as small molecules can be identified and bound by aptamers. Studying the interaction between aptamers and drugs, antibiotics or metabolites in detail is however difficult due to the lack of sophisticated analysis methods. Basic binding parameters of these small molecule-aptamer interactions such as binding affinity, stoichiometry and thermodynamics are elaborately to access using the state of the art technologies. The innovative MicroScale Thermophoresis (MST) is a novel, rapid and precise method to characterize these small molecule-aptamer interactions in solution at microliter scale. The technology is based on the movement of molecules through temperature gradients, a physical effect referred to as thermophoresis. The thermophoretic movement of a molecule depends - besides on its size - on charge and hydration shell. Upon the interaction of a small molecule and an aptamer, at least one of these parameters is altered, leading to a change in the movement behavior, which can be used to quantify molecular interactions independent of the size of the target molecule. The MST offers free choice of buffers, even measurements in complex bioliquids are possible. The dynamic affinity range covers the pM to mM range and is therefore perfectly suited to analyze small molecule-aptamer interactions. This section describes a protocol how quantitative binding parameters for aptamer-small molecule interactions can be obtained by MST. This is demonstrated by mapping down the binding site of the well-known ATP aptamer DH25.42 to a specific region at the adenine of the ATP molecule. Copyright © 2015 Elsevier Inc. All rights reserved.

Effects of confinement on the Rydberg molecule NeH

International Nuclear Information System (INIS)

Lo, J M H; Klobukowski, M; Bielinska-Waz, D; Diercksen, G H F; Schreiner, E W S

2005-01-01

Ab initio potential energy curves of the Rydberg NeH molecule in the presence of cylindrical spatial confinement were computed by the method of multi-reference configuration interaction with extended basis sets. The influence of the applied potential to the structures and spectra of the ground and excited states of NeH was analysed in terms of perturbation theory. In addition, the phenomenon of field-induced ionization was discussed

Rotational dependence of Fermi-type resonance interactions in molecules

Science.gov (United States)

Mikhailov, Vladimir M.; Smirnov, M. A.

1997-03-01

In Pasadena, (Milliken Lab., USA, 1930) F. Rossetti has observed in Raman spectrum of carbon-dioxide molecule the full symmetric vibration of carbon dioxide appeared as the group of four near lying lines instead of the waited single line. The true interpretation of this enigmatic effect (in that time) was given by E. Fermi -- accidental degeneration of the first excited state of the full symmetric vibration in carbon dioxide. It was the first example of the event observed later in various organic molecules. This event was named as resonance Fermi. The rotational dependence of Fermi type resonance interactions in quasirigid molecules in dominant approximation can be selected in an expansion of the effective vibration-rotation Hamiltonian Hvib- roteff by the operator H(g)(Fermi) equals H30 plus (Sigma) nH3n(g). Let us consider in detail the problem of the construction of the effective vibration-rotational Hamiltonian HVR yields Heff from the point of view of various ordering schemes (grouping) of the vibrational-rotational interactions with sequential analysis of the choice of the convenient grouping adequate to the spectroscopic problem.

Suppression and enhancement of non-native molecules within biological systems

Energy Technology Data Exchange (ETDEWEB)

Jones, E.A. [Surface Analysis Research Centre, CEAS, School of Chemical Engineering and Analytical Science, University of Manchester, Manchester M60 1QD (United Kingdom)]. E-mail: e.jones@postgrad.manchester.ac.uk; Lockyer, N.P. [Surface Analysis Research Centre, CEAS, School of Chemical Engineering and Analytical Science, University of Manchester, Manchester M60 1QD (United Kingdom); Vickerman, J.C. [Surface Analysis Research Centre, CEAS, School of Chemical Engineering and Analytical Science, University of Manchester, Manchester M60 1QD (United Kingdom)

2006-07-30

With the aim of evaluating the potential of SIMS to provide molecular information from small molecules within biological systems, here we investigate the effect of different biological compounds as they act as matrices. The results highlight the fact that the chemical environment of a molecule can have a significant effect on its limit of detection. This has implications for the imaging of drugs and xenobiotics in tissue sections and other biological matrices. A 1:1 mixture of the organic acid 2,4,6-trihydroxyacetophenone and the dipeptide valine-valine demonstrates that almost complete suppression of the [M + H]{sup +} ion of one compound can be caused by the presence of a compound of higher proton affinity. The significance of this is highlighted when two similar drug molecules, atropine (a neutral molecule) and ipratropium bromide (a quaternary nitrogen containing salt) are mixed with brain homogenate. The atropine [M + H]{sup +} ion shows significant suppression whilst the [M - Br]{sup +} of ipratopium bromide is detected at an intensity that can be rationalised by its decreased surface concentration. By investigating the effect of two abundant tissue lipids, cholesterol and dipalmitoylphosphatidyl choline (DPPC), on the atropine [M + H]{sup +} signal detected in mixtures with these lipids we see that the DPPC has a strong suppressing effect, which may be attributed to gas phase proton transfer.

Metal-Controlled Magnetoresistance at Room Temperature in Single-Molecule Devices.

Science.gov (United States)

Aragonès, Albert C; Aravena, Daniel; Valverde-Muñoz, Francisco J; Real, José Antonio; Sanz, Fausto; Díez-Pérez, Ismael; Ruiz, Eliseo

2017-04-26

The appropriate choice of the transition metal complex and metal surface electronic structure opens the possibility to control the spin of the charge carriers through the resulting hybrid molecule/metal spinterface in a single-molecule electrical contact at room temperature. The single-molecule conductance of a Au/molecule/Ni junction can be switched by flipping the magnetization direction of the ferromagnetic electrode. The requirements of the molecule include not just the presence of unpaired electrons: the electronic configuration of the metal center has to provide occupied or empty orbitals that strongly interact with the junction metal electrodes and that are close in energy to their Fermi levels for one of the electronic spins only. The key ingredient for the metal surface is to provide an efficient spin texture induced by the spin-orbit coupling in the topological surface states that results in an efficient spin-dependent interaction with the orbitals of the molecule. The strong magnetoresistance effect found in this kind of single-molecule wire opens a new approach for the design of room-temperature nanoscale devices based on spin-polarized currents controlled at molecular level.

Adhesion molecules

CERN Document Server

Preedy, Victor R

2016-01-01

This book covers the structure and classification of adhesion molecules in relation to signaling pathways and gene expression. It discusses immunohistochemical localization, neutrophil migration, and junctional, functional, and inflammatory adhesion molecules in pathologies such as leukocyte decompression sickness and ischemia reperfusion injury. Highlighting the medical applications of current research, chapters cover diabetes, obesity, and metabolic syndrome; hypoxia; kidney disease; smoking, atrial fibrillation, and heart disease, the brain and dementia; and tumor proliferation. Finally, it looks at molecular imaging and bioinformatics, high-throughput technologies, and chemotherapy.

Stokes-attenuated tunneling ionization of molecules

Science.gov (United States)

Kornev, Aleksei S.; Zon, Boris A.

2018-03-01

We set forth the quantum theory of ionic vibrational-level population by means of tunneling ionization of a molecule. Specific calculations are carried out for the H2 molecule. The results are in qualitative agreement with the experimental data [X. Urbain et al., Phys. Rev. Lett. 92, 163004 (2004), 10.1103/PhysRevLett.92.163004]. Our account for the excited vibrational levels reveals an interplay of two tendencies which contribute to the ionization rate: (i) It decreases due to additional energy absorption needed to populate these states and (ii) it increases together with the Franck-Condon factors which are large for these states. We show that these two tendencies practically compensate each other. The average quantitative disagreement between the theory and experiment amounts to ˜30 %. The same disagreement takes place when using the frozen approximation for the description of the nuclei motion. We demonstrated that the light-dressing effect for H2 leads to the dependence of the ionization rate on the angle between the molecule axis and the polarization vector of the radiation.

The Therapeutic Effect of the Antitumor Drug 11 Beta and Related Molecules on Polycystic Kidney Disease

Science.gov (United States)

2017-10-01

models (Somlo, Yale). Preparation work to assemble a collection of probes specific for oxidative stress genes and other PKD specific genes (as part... Worked : 6 Contribution to Project: Performance of experiments including those related to mitochondrial biology in vivo and unfolded protein...1 AWARD NUMBER: W81XWH-15-1-0364 TITLE: THE THERAPEUTIC EFFECT OF THE ANTITUMOR DRUG 11 BETA AND RELATED MOLECULES ON POLYYSTIC KIDNEY DISEASE

The Ia.2 Epitope Defines a Subset of Lipid Raft Resident MHC Class II Molecules Crucial to Effective Antigen Presentation1

Science.gov (United States)

Busman-Sahay, Kathleen; Sargent, Elizabeth; Harton, Jonathan A.; Drake, James R.

2016-01-01

Previous work has established that binding of the 11-5.2 anti-I-Ak mAb, which recognizes the Ia.2 epitope on I-Ak class II molecules, elicits MHC class II signaling, whereas binding of two other anti-I-Ak mAb that recognize the Ia.17 epitope fail to elicit signaling. Using a biochemical approach, we establish that the Ia.2 epitope recognized by the widely used 11-5.2 mAb defines a subset of cell surface I-Ak molecules predominantly found within membrane lipid rafts. Functional studies demonstrate that the Ia.2 bearing subset of I-Ak class II molecules is critically necessary for effective B cell–T cell interactions especially at low antigen doses, a finding consistent with published studies on the role of raft-resident class II molecules in CD4 T cell activation. Interestingly, B cells expressing recombinant I-Ak class II molecules possessing a β chain-tethered HEL peptide lack the Ia.2 epitope and fail to partition into lipid rafts. Moreover, cells expressing Ia.2 negative tethered peptide-class II molecules are severely impaired in their ability to present both tethered peptide or peptide derived from exogenous antigen to CD4 T cells. These results establish the Ia.2 epitope as defining a lipid raft-resident MHC class II confomer vital to the initiation of MHC class II restricted B cell–T cell interactions. PMID:21543648

Effects of microwave electric fields on the translational diffusion of dipolar molecules in surface potential: A simulation study

Science.gov (United States)

Kapranov, Sergey V.; Kouzaev, Guennadi A.

2018-01-01

Variations of effective diffusion coefficient of polar molecules exposed to microwave electric fields in a surface potential are studied by solving coupled stochastic differential equations of motion with a deterministic component of the surface force. Being an essential tool for the simulation interpretation, a theoretical approach to effective diffusion in surface potential is first developed. The effective diffusion coefficient is represented as the product of the normal diffusion coefficient and potential-dependent correction function, whose temperature dependence is close to the Arrhenius form. The analytically found zero-diffusion condition defines the state of thermal equilibrium at the surface. The diffusion of a water-like dipole molecule in the potential of graphite surface is simulated in the field-free conditions and in the presence of the alternating electric fields of various magnitude intensities and frequencies. Temperature dependence of the correction function exhibits field-induced variations of the effective Lennard-Jones energy parameter. It demonstrates maximum departure from the zero-field value at certain frequencies and intensities, which is associated with variations in the rotational dynamics. A concept of the amplitude-frequency resonance put forward to interpret the simulation results is explained using a heuristic reasoning and is corroborated by semi-quantitative considerations in terms of the Dissado-Hill cluster theory of dielectric relaxation.

Effect of doping of OH- and CN- on the liberation of I2 molecules in KI by gamma-irradiation, impurity concentration effect

International Nuclear Information System (INIS)

Shirke, A.K.; Pode, R.B.; Deshmukh, B.T.

1996-01-01

Photodecomposition of pure and doped KI powder (KI:KOH; KI:KCN; Impurity concentration, 100, 300, 500, 700 and 1000 ppm) to produce free I 2 molecules during gamma irradiation is studied with the help of absorption and IR measurements. Large number of I 2 molecules are formed in pure KI as compared to the doped samples. Hydroxide impurity increases the rate of liberation of I 2 molecules whereas the cyanide impurity decreases the rate of liberation of I 2 molecules. (Author)

Stability of matter-antimatter molecules

International Nuclear Information System (INIS)

Wong, Cheuk-Yin; Lee, Teck-Ghee

2011-01-01

Highlights: → We examine stability of matter-antimatter molecules with four constituents. → The binding of matter-antimatter molecules is a common phenomenon. → Molecules have bound states if ratio of constituent masses greater than ∼4. → We evaluate molecular binding energies and annihilation lifetimes. - Abstract: We examine the stability of matter-antimatter molecules by reducing the four-body problem into a simpler two-body problem with residual interactions. We find that matter-antimatter molecules with constituents (m 1 + ,m 2 - ,m-bar 2 + ,m-bar 1 - ) possess bound states if their constituent mass ratio m 1 /m 2 is greater than about 4. This stability condition suggests that the binding of matter-antimatter molecules is a rather common phenomenon. We evaluate the binding energies and eigenstates of matter-antimatter molecules (μ + e - )-(e + μ - ),(π + e - )-(e + π - ),(K + e - )-(e + K - ),(pe - )-(e + p-bar),(pμ - )-(μ + p-bar), and (K + μ - ) - (μ + K - ), which satisfy the stability condition. We estimate the molecular annihilation lifetimes in their s states.

Adiabatic Field-Free Alignment of Asymmetric Top Molecules with an Optical Centrifuge.

Science.gov (United States)

Korobenko, A; Milner, V

2016-05-06

We use an optical centrifuge to align asymmetric top SO_{2} molecules by adiabatically spinning their most polarizable O-O axis. The effective centrifugal potential in the rotating frame confines the sulfur atoms to the plane of the laser-induced rotation, leading to the planar molecular alignment that persists after the molecules are released from the centrifuge. The periodic appearance of the full three-dimensional alignment, typically observed only with linear and symmetric top molecules, is also detected. Together with strong in-plane centrifugal forces, which bend the molecules by up to 10 deg, permanent field-free alignment offers new ways of controlling molecules with laser light.

High levels of fetal DNA are associated with increased risk of spontaneous preterm delivery

DEFF Research Database (Denmark)

Jakobsen, Tanja R; Clausen, Frederik B; Rode, Line

2012-01-01

To assess whether spontaneous preterm delivery can be predicted from the amount of cell free fetal DNA (cffDNA) as determined by routine fetal RHD genotyping at 25 weeks' gestation.......To assess whether spontaneous preterm delivery can be predicted from the amount of cell free fetal DNA (cffDNA) as determined by routine fetal RHD genotyping at 25 weeks' gestation....

Modelling of energetic molecule-surface interactions

International Nuclear Information System (INIS)

Kerford, M.

2000-09-01

This thesis contains the results of molecular dynamics simulations of molecule-surface interactions, looking particularly at fullerene molecules and carbon surfaces. Energetic impacts of fullerene molecules on graphite create defect craters. The relationship between the parameters of the impacting molecule and the parameters of the crater axe examined and found to be a function of the energy and velocity of the impacting molecule. Less energetic fullerene molecules can be scattered from a graphite surface and the partitioning of energy after a scattering event is investigated. It is found that a large fraction of the kinetic energy retained after impact is translational energy, with a small fraction of rotational energy and a number of vibrational modes. At impact energies where the surface is not broken and at normal incidence, surface waves axe seen to occur. These waves axe used to develop a method of desorbing molecules from a graphite surface without damage to either the surface or the molecules being desorbed. A number of fullerene molecules are investigated and ways to increase the desorption yield are examined. It is found that this is a successful technique for desorbing large numbers of intact molecules from graphite. This technique could be used for desorbing intact molecules into a gas phase for mass spectrometric analysis. (author)

Amino Acid-Assisted Incorporation of Dye Molecules within Calcite Crystals.

Science.gov (United States)

Marzec, Bartosz; Green, David C; Holden, Mark A; Coté, Alexander S; Ihli, Johannes; Khalid, Saba; Kulak, Alexander; Walker, Daniel; Tang, Chiu; Duffy, Dorothy M; Kim, Yi-Yeoun; Meldrum, Fiona C

2018-05-23

Biomineralisation processes invariably occur in the presence of multiple organic additives, which act in combination to give exceptional control over structures and properties. However, few synthetic studies have investigated the cooperative effects of soluble additives. This work addresses this challenge and focuses on the combined effects of amino acids and coloured dye molecules. The experiments demonstrate that strongly coloured calcite crystals only form in the presence of Brilliant Blue R (BBR) and four of the seventeen soluble amino acids, as compared with almost colourless crystals using the dye alone. The active amino acids are identified as those which themselves effectively occlude in calcite, suggesting a mechanism where they can act as chaperones for individual molecules or even aggregates of dyes molecules. These results provide new insight into crystal-additive interactions and suggest a novel strategy for generating materials with target properties. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Identification of a cytotoxic molecule in heat-modified citrus pectin.

Science.gov (United States)

Leclere, Lionel; Fransolet, Maude; Cambier, Pierre; El Bkassiny, Sandy; Tikad, Abdellatif; Dieu, Marc; Vincent, Stéphane P; Van Cutsem, Pierre; Michiels, Carine

2016-02-10

Modified forms of citrus pectin possess anticancer properties. However, their mechanism of action and the structural features involved remain unclear. Here, we showed that citrus pectin modified by heat treatment displayed cytotoxic effects in cancer cells. A fractionation approach was used aiming to identify active molecules. Dialysis and ethanol precipitation followed by HPLC analysis evidenced that most of the activity was related to molecules with molecular weight corresponding to low degree of polymerization oligogalacturonic acid. Heat-treatment of galacturonic acid also generated cytotoxic molecules. Furthermore, heat-modified galacturonic acid and heat-fragmented pectin contained the same molecule that induced cell death when isolated by HPLC separation. Mass spectrometry analyses revealed that 4,5-dihydroxy-2-cyclopenten-1-one was one cytotoxic molecule present in heat-treated pectin. Finally, we synthesized the enantiopure (4R,5R)-4,5-dihydroxy-2-cyclopenten-1-one and demonstrated that this molecule was cytotoxic and induced a similar pattern of apoptotic-like features than heat-modified pectin. Copyright © 2015 Elsevier Ltd. All rights reserved.

The effect of soy protein beverages on serum cell adhesion molecule concentrations in prehypertensive/stage 1 hypertensive individuals.

Science.gov (United States)

Dettmer, Michelle; Alekel, D Lee; Lasrado, Joanne A; Messina, Mark; Carriquiry, Alicia; Heiberger, Kevin; Stewart, Jeanne W; Franke, Warren

2012-04-01

Prehypertensive and hypertensive individuals are at increased risk of atherosclerotic cardiovascular disease (CVD), in part because hypertension contributes to endothelial dysfunction and increased cell adhesion molecule expression. Soy protein and isoflavones may favorably alter CVD risk factors, and hence the aim of this study was to determine whether intake of cow's milk compared with soy beverage prepared from whole soy bean (WSB) or soy protein isolate (SPI) would lower soluble cell adhesion molecule concentrations as a means of decreasing CVD risk. We enrolled healthy prehypertensive/stage 1 hypertensive men (n = 60; 18-63 years) and premenopausal women (n = 8; 20-48 years). Participants were randomized to 1 of 3 groups for 8 weeks: cow's milk (600 mL/d), SPI beverage (840 mL/d; 30.1 mg total isoflavones/d), or WSB beverage (840 mL/d; 91.4 mg total isoflavones/d). We measured soluble vascular cell adhesion molecule-1 (VCAM-1), intercellular cell adhesion molecule-1 (ICAM-1), and endothelial-leukocyte adhesion molecule-1 (E-selectin) concentrations at baseline and week 8. Soluble CAM concentrations were not altered by treatment and did not differ between prehypertensive and hypertensive participants. However, analysis of variance indicated a treatment × gender interaction (gender effect) for ICAM-1 (p = 0.0037) but not for E-selectin (p = 0.067) or VCAM-1 (p = 0.16). Men had higher concentrations of ICAM-1 and E-selectin, respectively, at baseline (p = 0.0071, p = 0.049) and week 8 (p = 0.0054, p = 0.038) than women did. Neither intake of cow's milk nor soy beverage for 8 weeks altered soluble CAM concentrations in prehypertensive/stage 1 hypertensive individuals, suggesting that neither type of beverage diminished atherosclerotic CVD risk in mildly hypertensive individuals by way of improving circulating CAM concentrations.

The Synergistic Effect between Electrical and Chemical Factors in Plasma Gene/Molecule-Transfection

Science.gov (United States)

Jinno, Masafumi

2016-09-01

This study has been done to know what kind of factors in plasma and processes on cells promote plasma gene/molecule transfection. We have discovered a new plasma source using a microcapillary electrode which enables high transfection efficiency and high cell survivability simultaneously. However, the mechanism of the transfection by plasma was not clear. To clarify the transfection mechanisms by micro plasma, we focused on the effects of electrical (current, charge, field, etc.) and chemical (radicals, RONS, etc.) factors generated by the micro plasma and evaluated the contribution weight of three groups of the effects and processes, i.e. electrical, chemical and biochemical ones. At first, the necessity of the electrical factors was estimated by the laser produced plasma (LPP). Mouse L-929 fibroblast cell was cultured on a 96-well plate or 12-well micro slide chamber. Plasmids pCX-EGFP in Tris-EDTA buffer was dropped on the cells and they were exposed to the capillary discharge plasma (CDP) or the LPP. In the case of the CDP, the plasma was generated between the tip of the capillary electrode and the cells so that both electrical and chemical factors were supplied to the cells. In this setup, about 20% of average transfection efficiency was obtained. In the case of the LPP, the plasma was generated apart from the cells so that electrical factors were not supplied to the cells. In this setup, no transfection was observed. These results show that the electrical factors are necessary for the plasma gene transfection. Next, the necessity of the chemical factors was estimated the effect of catalase to remove H2O2 in CDP. The transfection efficiency decreased to 0.4 by scavenging H2O2 with catalase. However, only the solution of H2O2 caused no gene transfection in cells. These results shows that H2O2 is important species to cause gene/molecule transfection but still needs a synergistic effect with electrical or other chemical factors. This work was partly supported by

Elastic scattering of low energy electrons by hydrogen molecule

International Nuclear Information System (INIS)

Freitas, L.C.G.; Mu-Tao, L.; Botelho, L.F.

1987-01-01

The coherent version of the Renormalized Multiple-Centre Potential Model (RMPM) has been extended to treat the elastic scattering of low energy electrons by H2 molecule. The intramolecular Multiple Scattering (MS) effect has also been included. The comparison against the experimental data shows that the inclusion of the MS improves significantly with experiment. The extension of the present method to study electron-polyatomic molecule interaction is also discussed. (author) [pt

The effect of spatial confinement on the noble-gas HArF molecule: structure and electric properties

International Nuclear Information System (INIS)

Kozłowska, Justyna; Bartkowiak, Wojciech

2014-01-01

Highlights: • The structure and electrical properties of HArF in spatial confinement are analyzed. • Orbital compression leads to decrease of bond lengths in the HArF molecule. • Spatial restriction causes a drop of the molecular (hyper)polarizabilities. • Spatial confinement reduces the electron correlation contribution to μ, α and β. - Abstract: A systematic study on the dipole moment and (hyper)polarizabilities of argon fluorohydride under spatial restriction was performed. Detailed analysis of the confinement induced changes in the structure of HArF is also presented. In order to render the influence of chemical compression on the properties in question a two-dimensional harmonic oscillator potential, mimicking a cylindrical confinement, was applied. Through the comparison of the results obtained for HArF with those of HF the effect of Ar insertion on the above properties was discussed. A hierarchy of ab initio methods including HF, MP2, CCSD and CCSD(T), has been employed to investigate the effect of orbital compression on the electron correlation contribution to the studied electric properties. It was observed that the external confining potential modifies the electronic contributions to the dipole moment and (hyper)polarizabilities of HArF. In particular, the first hyperpolarizability of HArF is remarkably smaller than that of the unconfined HArF molecule

The effect of spatial confinement on the noble-gas HArF molecule: structure and electric properties

Energy Technology Data Exchange (ETDEWEB)

Kozłowska, Justyna; Bartkowiak, Wojciech, E-mail: wojciech.bartkowiak@pwr.edu.pl

2014-09-30

Highlights: • The structure and electrical properties of HArF in spatial confinement are analyzed. • Orbital compression leads to decrease of bond lengths in the HArF molecule. • Spatial restriction causes a drop of the molecular (hyper)polarizabilities. • Spatial confinement reduces the electron correlation contribution to μ, α and β. - Abstract: A systematic study on the dipole moment and (hyper)polarizabilities of argon fluorohydride under spatial restriction was performed. Detailed analysis of the confinement induced changes in the structure of HArF is also presented. In order to render the influence of chemical compression on the properties in question a two-dimensional harmonic oscillator potential, mimicking a cylindrical confinement, was applied. Through the comparison of the results obtained for HArF with those of HF the effect of Ar insertion on the above properties was discussed. A hierarchy of ab initio methods including HF, MP2, CCSD and CCSD(T), has been employed to investigate the effect of orbital compression on the electron correlation contribution to the studied electric properties. It was observed that the external confining potential modifies the electronic contributions to the dipole moment and (hyper)polarizabilities of HArF. In particular, the first hyperpolarizability of HArF is remarkably smaller than that of the unconfined HArF molecule.

Single-molecule dynamics in nanofabricated traps

Science.gov (United States)

Cohen, Adam

2009-03-01

The Anti-Brownian Electrokinetic trap (ABEL trap) provides a means to immobilize a single fluorescent molecule in solution, without surface attachment chemistry. The ABEL trap works by tracking the Brownian motion of a single molecule, and applying feedback electric fields to induce an electrokinetic motion that approximately cancels the Brownian motion. We present a new design for the ABEL trap that allows smaller molecules to be trapped and more information to be extracted from the dynamics of a single molecule than was previously possible. In particular, we present strategies for extracting dynamically fluctuating mobilities and diffusion coefficients, as a means to probe dynamic changes in molecular charge and shape. If one trapped molecule is good, many trapped molecules are better. An array of single molecules in solution, each immobilized without surface attachment chemistry, provides an ideal test-bed for single-molecule analyses of intramolecular dynamics and intermolecular interactions. We present a technology for creating such an array, using a fused silica plate with nanofabricated dimples and a removable cover for sealing single molecules within the dimples. With this device one can watch the shape fluctuations of single molecules of DNA or study cooperative interactions in weakly associating protein complexes.

Single molecules and nanotechnology

CERN Document Server

Vogel, Horst

2007-01-01

This book focuses on recent advances in the rapidly evolving field of single molecule research. These advances are of importance for the investigation of biopolymers and cellular biochemical reactions, and are essential to the development of quantitative biology. Written by leading experts in the field, the articles cover a broad range of topics, including: quantum photonics of organic dyes and inorganic nanoparticles their use in detecting properties of single molecules the monitoring of single molecule (enzymatic) reactions single protein (un)folding in nanometer-sized confined volumes the dynamics of molecular interactions in biological cells The book is written for advanced students and scientists who wish to survey the concepts, techniques and results of single molecule research and assess them for their own scientific activities.

Adsorption of metalorganic molecules on metal-semiconductor systems

Energy Technology Data Exchange (ETDEWEB)

Brand, Christian; Schmeidel, Jedrzej; Chen, Wei; Tegenkamp, Christoph; Pfnuer, Herbert [Institut fuer Festkoerperphysik, Leibniz Universitaet Hannover (Germany)

2011-07-01

The controlled implementation of single molecules in appropriate contact assemblies is the ultimate realization of an ultra-small device structure. Besides extremely high integration densities the functionalities of the devices are adjustable by chemical synthesis. However, the interaction of the molecule with its environment is decisive. The adsorption of ferrocene-1,1'-dithiol (FDT) on Ag-{radical}(3) reconstructions on nominally flat and vicinal Si(111) substrates has been studied. The FDT was chosen because of its large conductance and high structural flexibility with respect to rotation of the two cyclopentadienyl (Cp) rings. The reconstruction is a prototype of a highly conductive low dimensional electron gas on a technologically relevant substrate. The adsorption of intact molecules takes place predominantly at defect sites, e.g. vacancy and step structures. Submolecular resolution showing the Cp-ring structure was obtained at perfect terrace sites. Due to chemisorption of the S-atoms at hollow sites the molecule axis is oriented parallel to the substrate. The initial rotational flexibility is frozen and only tow different rotated configurations were found. The adsorption geometry is confirmed by VASP calculations. Recently, Ag reconstructions on Si(557) substrates have been used. The effect of the uniaxial step configuration towards the adsorption of the FDT molecules is discussed.

Anisotropy in highly charged ion induced molecule fragmentation

International Nuclear Information System (INIS)

Juhasz, Z.; Sulik, B.; Fremont, F.; Chesnel, J.Y.; Hajaji, A.

2006-01-01

Complete text of publication follows. Studying fragmentation processes of biologically relevant molecules due to highly charged ion impact is important to understand radiation damage in biological tissues. Energy spectra of the charged molecule fragments may reveal the different fragmentation patterns meanwhile the angular distributions of the fragments characterize the dependence of fragmentation probability on the initial orientation of the molecule. The research to explore the angular distribution of the molecule fragments has only recently been started[1]. In 2006 we performed measurements at ARIBE facility at GANIL, Caen (France), in order to investigate orientation effects in molecule fragmentation. Fragmentation of H 2 O, C 6 H 6 and CH 4 , which represent different level of symmetry, have been studied by 60 keV N 6+ ion impact. Energy spectra of the charged fragments at different observation angles have been taken. As our example spectra show the different protonic peaks can be attributed to different fragmentation processes. Significant anisotropy can be seen in the different processes. The strongest evidence for the anisotropy can be seen in the spectra of C 6 H 6 , where the spectra appear isotropic in almost the whole observed energy range except one peak, which has a strong angular dependence and is maximal around 90 deg. (author)

Molecules in strong laser fields. In depth study of H{sub 2} molecule

Energy Technology Data Exchange (ETDEWEB)

Awasthi, Manohar

2009-10-29

above-threshold-ionization peaks is also demonstrated. The CI-TDSE results for H{sub 2} are used for testing the validity of SAE approximation. In strong field physics, there are models based on the SAE approximation. Most popular are the Ammosov-Delone-Krainov (ADK) model, a molecular version of the ADK model called MO-ADK (MO stands for molecular orbital) and the strong field approximation (SFA). The validity of the second method for the solution of TDSE in SAE approximation is investigated by applying it to H{sub 2} molecule where the exact two-electron results were already calculated using CI-TDSE. The SAE method uses density-functional-theory (DFT) for the description of field-free eigenstates and is thus abbreviated as DFT-SAE-TDSE. Since DFT is used for the calculation of field-free states, different functionals were also tested. The validity of MO-ADK model is also investigated. After establishing the DFT-SAE-TDSE method, the first excited state B{sup 1}{sigma}{sub u}{sup +} of H{sub 2} is studied over a large range of laser parameters. The effect of the closely lying excited states on ionization and excitation is studied. After successful testing of DFT-SAE-TDSE method on H{sub 2} molecule, the results for larger molecules like N{sub 2}, O{sub 2} and C{sub 2}H{sub 2} in the DFT-SAE framework are presented. (orig.)

Scattering of atoms by molecules adsorbed at solid surfaces

International Nuclear Information System (INIS)

Parra, Zaida.

1988-01-01

The formalism of collisional time-correlation functions, appropriate for scattering by many-body targets, is implemented to study energy transfer in the scattering of atoms and ions from molecules adsorbed on metal surfaces. Double differential cross-sections for the energy and angular distributions of atoms and ions scattered by a molecule adsorbed on a metal surface are derived in the limit of impulsive collisions and within a statistical model that accounts for single and double collisions. They are found to be given by the product of an effective cross-section that accounts for the probability of deflection into a solid angle times a probability per unit energy transfer. A cluster model is introduced for the vibrations of an adsorbed molecule which includes the molecular atoms, the surface atoms binding the molecule, and their nearest neighbors. The vibrational modes of CO adsorbed on a Ni(001) metal surface are obtained using two different cluster models to represent the on-top and bridge-bonding situations. A He/OC-Ni(001) potential is constructed from a strongly repulsive potential of He interacting with the oxygen atom in the CO molecule and a van der Waals attraction accounting for the He interaction with the free Ni(001) surface. A potential is presented for the Li + /OC-Ni(001) where a coulombic term is introduced to account for the image force. Trajectory studies are performed and analyzed in three dimensions to obtain effective classical cross-sections for the He/OC-Ni(001) and Li + /OC-Ni(001) systems. Results for the double differential cross-sections are presented as functions of scattering angles, energy transfer and collisional energy. Temperature dependence results are also analyzed. Extensions of the approach and inclusion of effects such as anharmonicity, collisions at lower energies, and applications of the approach to higher coverages are discussed

Organizing and addressing magnetic molecules.

Science.gov (United States)

Gatteschi, Dante; Cornia, Andrea; Mannini, Matteo; Sessoli, Roberta

2009-04-20

Magnetic molecules ranging from simple organic radicals to single-molecule magnets (SMMs) are intensively investigated for their potential applications in molecule-based information storage and processing. The goal of this Article is to review recent achievements in the organization of magnetic molecules on surfaces and in their individual probing and manipulation. We stress that the inherent fragility and redox sensitivity of most SMM complexes, combined with the noninnocent role played by the substrate, ask for a careful evaluation of the structural and electronic properties of deposited molecules going beyond routine methods for surface analysis. Detailed magnetic information can be directly obtained using X-ray magnetic circular dichroism or newly emerging scanning probe techniques with magnetic detection capabilities.

Layers of Cold Dipolar Molecules in the Harmonic Approximation

DEFF Research Database (Denmark)

R. Armstrong, J.; Zinner, Nikolaj Thomas; V. Fedorov, D.

2012-01-01

We consider the N-body problem in a layered geometry containing cold polar molecules with dipole moments that are polarized perpendicular to the layers. A harmonic approximation is used to simplify the hamiltonian and bound state properties of the two-body inter-layer dipolar potential are used...... to adjust this effective interaction. To model the intra-layer repulsion of the polar molecules, we introduce a repulsive inter-molecule potential that can be parametrically varied. Single chains containing one molecule in each layer, as well as multi-chain structures in many layers are discussed...... and their energies and radii determined. We extract the normal modes of the various systems as measures of their volatility and eventually of instability, and compare our findings to the excitations in crystals. We find modes that can be classified as either chains vibrating in phase or as layers vibrating against...

Study of the effect of gamma radiation on the molecule of tetracycline concerning its behavior as complexing and extracting agent

International Nuclear Information System (INIS)

Andrade e Silva, Leonardo Gondim de

1982-01-01

Both solvent extraction and spectrophotometric techniques were used to show the alterations that gamma radiation causes in the behavior of tetracycline molecule as far as its extracting and complexing power are concerned. The effect of gamma radiation on the solid tetracycline molecule, benzyl alcohol and on the solution of both was examined in solvent extraction systems whose aqueous phases were made up by 152 Eu- 154 Eu radioactive tracer solutions and whose organic phases were constituted by tetracycline-benzyl alcohol solutions. Experiments were performed in order to determine whether or not the water used for the pre-saturation of benzyl alcohol would influence the radiolysis of tetracycline. Solvent extraction and spectrophotometry were the techniques used to obtain the necessary data. Absorption spectra of irradiated tetracycline benzyl alcohol solutions submitted to several gamma radiation doses were examined and the alterations shown by these spectra were examined. The effect of gamma radiation on the tetracycline molecule was also studied when tetracycline-benzyl alcohol solutions were irradiated under several gaseous atmospheres, namely: O 2 , N 2 , SF 6 and N 2 O. The variation on the concentration of the tetracycline-benzyl alcohol solution caused by several doses of gamma radiation was determined by using the spectrophotometric technique. (author)

Molecule-by-Molecule Writing Using a Focused Electron Beam

DEFF Research Database (Denmark)

Van Dorp, Willem F.; Zhang, Xiaoyan; Feringa, Ben L.

2012-01-01

atoms also be written with an electron beam? We verify this with focused electron-beam-induced deposition (FEBID), a direct-write technique that has the current record for the smallest feature written by (electron) optical lithography. We show that the deposition of an organometallic precursor...... on graphene can be followed molecule-by-molecule with FEBID. The results show that mechanisms that are inherent to the process inhibit a further increase in control over the process. Hence, our results present the resolution limit of (electron) optical lithography techniques. The writing of isolated...

Observation of pendular butterfly Rydberg molecules

Science.gov (United States)

Niederprüm, Thomas; Thomas, Oliver; Eichert, Tanita; Lippe, Carsten; Pérez-Ríos, Jesús; Greene, Chris H.; Ott, Herwig

2016-01-01

Engineering molecules with a tunable bond length and defined quantum states lies at the heart of quantum chemistry. The unconventional binding mechanism of Rydberg molecules makes them a promising candidate to implement such tunable molecules. A very peculiar type of Rydberg molecules are the so-called butterfly molecules, which are bound by a shape resonance in the electron–perturber scattering. Here we report the observation of these exotic molecules and employ their exceptional properties to engineer their bond length, vibrational state, angular momentum and orientation in a small electric field. Combining the variable bond length with their giant dipole moment of several hundred Debye, we observe counter-intuitive molecules which locate the average electron position beyond the internuclear distance. PMID:27703143

Passing Current through Touching Molecules

DEFF Research Database (Denmark)

Schull, G.; Frederiksen, Thomas; Brandbyge, Mads

2009-01-01

The charge flow from a single C-60 molecule to another one has been probed. The conformation and electronic states of both molecules on the contacting electrodes have been characterized using a cryogenic scanning tunneling microscope. While the contact conductance of a single molecule between two...

Photochemical dynamics of surface oriented molecules

International Nuclear Information System (INIS)

Ho, W.

1992-01-01

The period 8/01/91-7/31/92 is the first year of a new project titled ''Photochemical Dynamics of Surface Oriented Molecules'', initiated with DOE Support. The main objective of this project is to understand the dynamics of elementary chemical reactions by studying photochemical dynamics of surface-oriented molecules. In addition, the mechanisms of photon-surface interactions need to be elucidated. The strategy is to carry out experiments to measure the translational energy distribution, as a function of the angle from the surface normal, of the photoproducts by time-of-flight (TOF) technique by varying the photon wavelength, intensity, polarization, and pulse duration. By choosing adsorbates with different bonding configuration, the effects of adsorbate orientation on surface photochemical dynamics can be studied

Multiple molecule effects on the cooperativity of protein folding transitions in simulations

Science.gov (United States)

Lewis, Jacob I.; Moss, Devin J.; Knotts, Thomas A.

2012-06-01

Though molecular simulation of proteins has made notable contributions to the study of protein folding and kinetics, disagreement between simulation and experiment still exists. One of the criticisms levied against simulation is its failure to reproduce cooperative protein folding transitions. This weakness has been attributed to many factors such as a lack of polarizability and adequate capturing of solvent effects. This work, however, investigates how increasing the number of proteins simulated simultaneously can affect the cooperativity of folding transitions — a topic that has received little attention previously. Two proteins are studied in this work: phage T4 lysozyme (Protein Data Bank (PDB) ID: 7LZM) and phage 434 repressor (PDB ID: 1R69). The results show that increasing the number of proteins molecules simulated simultaneously leads to an increase in the macroscopic cooperativity for transitions that are inherently cooperative on the molecular level but has little effect on the cooperativity of other transitions. Taken as a whole, the results identify one area of consideration to improving simulations of protein folding.

Cytotoxicity Effects of Different Surfactant Molecules Conjugated to Carbon Nanotubes on Human Astrocytoma Cells

Science.gov (United States)

Dong, Lifeng; Witkowski, Colette M.; Craig, Michael M.; Greenwade, Molly M.; Joseph, Katherine L.

2009-12-01

Phase contrast and epifluorescence microscopy were utilized to monitor morphological changes in human astrocytoma cells during a time-course exposure to single-walled carbon nanotube (SWCNT) conjugates with different surfactants and to investigate sub-cellular distribution of the nanotube conjugates, respectively. Experimental results demonstrate that cytotoxicity of the nanotube/surfactant conjugates is related to the toxicity of surfactant molecules attached on the nanotube surfaces. Both sodium dodecyl sulfate (SDS) and sodium dodecylbenzene sulfonate (SDBS) are toxic to cells. Exposure to CNT/SDS conjugates (0.5 mg/mL) for less than 5 min caused changes in cell morphology resulting in a distinctly spherical shape compared to untreated cells. In contrast, sodium cholate (SC) and CNT/SC did not affect cell morphology, proliferation, or growth. These data indicate that SC is an environmentally friendly surfactant for the purification and dispersion of SWCNTs. Epifluorescence microscopy analysis of CNT/DNA conjugates revealed distribution in the cytoplasm of cells and did not show adverse effects on cell morphology, proliferation, or viability during a 72-h incubation. These observations suggest that the SWCNTs could be used as non-viral vectors for diagnostic and therapeutic molecules across the blood-brain barrier to the brain and the central nervous system.

Single-Molecule Sensing with Nanopore Confinement: from Chemical Reactions to Biological Interactions.

Science.gov (United States)

Lin, Yao; Ying, Yi-Lun; Gao, Rui; Long, Yi-Tao

2018-03-25

The nanopore can generate an electrochemical confinement for single-molecule sensing which help understand the fundamental chemical principle in nanoscale dimensions. By observing the generated ionic current, individual bond-making and bond-breaking steps, single biomolecule dynamic conformational changes and electron transfer processes that occur within pore can be monitored with high temporal and current resolution. These single-molecule studies in nanopore confinement are revealing information about the fundamental chemical and biological processes that cannot be extracted from ensemble measurements. In this concept, we introduce and discuss the electrochemical confinement effects on single-molecule covalent reactions, conformational dynamics of individual molecules and host-guest interactions in protein nanopores. Then, we extend the concept of nanopore confinement effects to confine electrochemical redox reactions in solid-state nanopores for developing new sensing mechanisms. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Enzyme Molecules in Solitary Confinement

Directory of Open Access Journals (Sweden)

Raphaela B. Liebherr

2014-09-01

Full Text Available Large arrays of homogeneous microwells each defining a femtoliter volume are a versatile platform for monitoring the substrate turnover of many individual enzyme molecules in parallel. The high degree of parallelization enables the analysis of a statistically representative enzyme population. Enclosing individual enzyme molecules in microwells does not require any surface immobilization step and enables the kinetic investigation of enzymes free in solution. This review describes various microwell array formats and explores their applications for the detection and investigation of single enzyme molecules. The development of new fabrication techniques and sensitive detection methods drives the field of single molecule enzymology. Here, we introduce recent progress in single enzyme molecule analysis in microwell arrays and discuss the challenges and opportunities.

A Mott-like State of Molecules

International Nuclear Information System (INIS)

Duerr, S.; Volz, T.; Syassen, N.; Bauer, D. M.; Hansis, E.; Rempe, G.

2006-01-01

We prepare a quantum state where each site of an optical lattice is occupied by exactly one molecule. This is the same quantum state as in a Mott insulator of molecules in the limit of negligible tunneling. Unlike previous Mott insulators, our system consists of molecules which can collide inelastically. In the absence of the optical lattice these collisions would lead to fast loss of the molecules from the sample. To prepare the state, we start from a Mott insulator of atomic 87Rb with a central region, where each lattice site is occupied by exactly two atoms. We then associate molecules using a Feshbach resonance. Remaining atoms can be removed using blast light. Our method does not rely on the molecule-molecule interaction properties and is therefore applicable to many systems

[The importance of antenatal immunoprophylaxis for prevention of hemolytic disease of the fetus and newborn].

Science.gov (United States)

Starcević, Mirta; Mataija, Marina; Sović, Dragica; Dodig, Javorka; Matijević, Ratko; Kukuruzović, Monika

2011-03-01

Hemolytic disease of the fetus and newborn (HDFN) is a consequence of maternal alloimmunization against fetal red blood cell antigens. Alloimmunization against D antigen from Rhesus (Rh) blood group system is particularly important because of its strong immunogenicity. During the last few decades, the introduction of RhD prophylaxis by postpartum administration of anti-D immunoglobulin to RhD negative women, now improved with antenatal prophylaxis, has led to a dramatic decrease in perinatal mortality and morbidity from HDFN. However, severe cases have not disappeared, mostly due to prophylaxis failure. In our case, inappropriate prenatal care during the first pregnancy in an RhD negative mother resulted in primary immunization. In the next pregnancy with an RhD positive child, the mother's secondary immune response was extremely strong and led to early development of severe fetal anemia. The fetus survived thanks to the treatment with intrauterine transfusions (IUT), but they caused suppression of erythropoiesis, which lasted for months after birth. The long lasting, late anemia was treated with repeated postnatal red cell transfusions and recombinant human erythropoietin (rHuEPO). Despite the severity of HDFN in our case, the short-term outcome is good. The boy has normal growth until now, but due to the possibility of an adverse long-term neurodevelopmental outcome, this case requires continuous follow up. It also reminds of the fact that RhD alloimmunization remains an actual problem in daily routine. Antenatal prophylaxis is a crucial step in quality care of those who are at a risk of HDFN.

Angiotensin converting enzyme DD genotype is associated with development of rheumatic heart disease in Egyptian children.

Science.gov (United States)

Morsy, Mohamed-Mofeed Fawaz; Abdelaziz, Nada Abdelmohsen Mohamed; Boghdady, Ahmed Mohamed; Ahmed, Hydi; Abu Elfadl, Essam Mohamed; Ismail, Mohamed Ali

2011-01-01

Angiotensin converting enzyme (ACE) gene polymorphism was previously studied in some cardiovascular diseases. There are only few studies which investigated this polymorphism in patients with rheumatic heart disease (RHD). The results of these investigations are inconsistent. Furthermore, gene polymorphism distribution is different in various ethnic populations. We conducted this study to demonstrate this gene polymorphism in Egyptian children with RHD. Leukocytes DNA was extracted from 139 patients with RHD and 79 healthy control children. After amplification by the PCR, the products were separated by electrophoresis in 6% polyacrylamide gel and visualized after ethidium bromide staining with UV light. The PCR product is a 190-bp fragment in the absence of the insertion (D allele) and a 490-bp fragment in the presence of the insertion (I allele). Gene polymorphism was as follows: DD gene when lane contains only 190-bp fragment, II gene when lane contains only 490-bp fragment and ID gene when lane contains both fragments. We found that gene polymorphism in both control and patients groups followed the following order of distribution from highest to lowest: ID, II, DD gene. The frequency in control group was 49.4, 36.7, and 13.9%, respectively. In patients groups, the gene frequency was 42.5, 30.9, and 26.6%, respectively. DD gene frequency differs significantly between the two groups. We concluded that patients with RHD have a higher ACE-DD genotype than normal control. ACE-DD genotype may be a risk factor for RHD in Egyptian children.

You may now kiss the bride: Interpretation of social situations by individuals with right or left hemisphere injury.

Science.gov (United States)

Baldo, Juliana V; Kacinik, Natalie A; Moncrief, Amber; Beghin, Francesca; Dronkers, Nina F

2016-01-08

While left hemisphere damage (LHD) has been clearly shown to cause a range of language impairments, patients with right hemisphere damage (RHD) also exhibit communication deficits, such as difficulties processing prosody, discourse, and social contexts. In the current study, individuals with RHD and LHD were directly compared on their ability to interpret what a character in a cartoon might be saying or thinking, in order to better understand the relative role of the right and left hemisphere in social communication. The cartoon stimuli were manipulated so as to elicit more or less formulaic responses (e.g., a scene of a couple being married by a priest vs. a scene of two people talking, respectively). Participants' responses were scored by blind raters on how appropriately they captured the gist of the social situation, as well as how formulaic and typical their responses were. Results showed that RHD individuals' responses were rated as significantly less appropriate than controls and were also significantly less typical than controls and individuals with LHD. Individuals with RHD produced a numerically lower proportion of formulaic expressions than controls, but this difference was only a trend. Counter to prediction, the pattern of performance across participant groups was not affected by how constrained/formulaic the social situation was. The current findings expand our understanding of the roles that the right and left hemispheres play in social processing and communication and have implications for the potential treatment of social communication deficits in individuals with RHD. Published by Elsevier Ltd.

Electron-vibron coupling effects on electron transport via a single-molecule magnet

Science.gov (United States)

McCaskey, Alexander; Yamamoto, Yoh; Warnock, Michael; Burzurí, Enrique; van der Zant, Herre S. J.; Park, Kyungwha

2015-03-01

We investigate how the electron-vibron coupling influences electron transport via an anisotropic magnetic molecule, such as a single-molecule magnet (SMM) Fe4, by using a model Hamiltonian with parameter values obtained from density-functional theory (DFT). The magnetic anisotropy parameters, vibrational energies, and electron-vibron coupling strengths of the Fe4 are computed using DFT. A giant spin model is applied to the Fe4 with only two charge states, specifically a neutral state with a total spin S =5 and a singly charged state with S =9 /2 , which is consistent with our DFT result and experiments on Fe4 single-molecule transistors. In sequential electron tunneling, we find that the magnetic anisotropy gives rise to new features in the conductance peaks arising from vibrational excitations. In particular, the peak height shows a strong, unusual dependence on the direction as well as magnitude of applied B field. The magnetic anisotropy also introduces vibrational satellite peaks whose position and height are modified with the direction and magnitude of applied B field. Furthermore, when multiple vibrational modes with considerable electron-vibron coupling have energies close to one another, a low-bias current is suppressed, independently of gate voltage and applied B field, although that is not the case for a single mode with a similar electron-vibron coupling. In the former case, the conductance peaks reveal a stronger B -field dependence than in the latter case. The new features appear because the magnetic anisotropy barrier is of the same order of magnitude as the energies of vibrational modes with significant electron-vibron coupling. Our findings clearly show the interesting interplay between magnetic anisotropy and electron-vibron coupling in electron transport via the Fe4. Similar behavior can be observed in transport via other anisotropic magnetic molecules.

Dissociation in small molecules

International Nuclear Information System (INIS)

Dehmer, P.M.

1982-01-01

The study of molecular dissociation processes is one of the most interesting areas of modern spectroscopy owing to the challenges presented bt even the simplest of diatomic molecules. This paper reviews the commonly used descriptions of molecular dissociation processes for diatomic molecules, the selection rules for predissociation, and a few of the principles to be remembered when one is forced to speculate about dissociation mechanisms in a new molecule. Some of these points will be illustrated by the example of dissociative ionization in O 2

A novel strontium-rhodium hydride

International Nuclear Information System (INIS)

Bortz, M.; Yvon, K.; Fauth, F.

1997-01-01

The attempt to determine the structure of 'LiSr 2 RhD 6 ' that was reported to crystallize in a tetragonal primitive cell with one formula unit by neutron diffraction experiments on powder samples at room temperature and at 1.5 K led to the discovery of a new tetragonal deuteride of refined composition Sr 2 RhD 6 . (author) 2 figs., 3 refs

Effect of molecular structure on fragmentation of isolated organic molecules in solid rare gas matrices

International Nuclear Information System (INIS)

Kobzarenko, A.V.; Sukhov, F.F.; Orlov, A.Yu.; Kovalev, G.V.; Baranova, I.A.; Feldman, V.I.

2012-01-01

The effect of excess energy on the primary radical cations of bifunctional carbonyl compounds and aliphatic alkynes was simulated by matrix isolation method using rare gas matrices with various ionization potentials. The formation of fragmentation products was monitored by EPR and FTIR spectroscopy. It was shown that the radical cations of bifunctional compounds (CH 3 OCH 2 COCH 3 and CH 3 COCOCH 3 ) dissociated effectively yielding · CH 3 radicals upon irradiation in solid argon matrix at T≤16 K. In addition to isolated methyl radicals, the radical pairs consisting of two methyl radicals separated by two CO molecules were detected in the case of diacetyl. The probability of fragmentation decreases with the decreasing excess energy by switching from Ar to Xe. In general, bifunctional molecules were found to be less stable to “hot” ionic fragmentation in low-temperature solids in comparison with simple prototype compounds. In the case of alkynes of the R--C≡CH type, a noticeable yield of fragmentation products was observed when R=–C(CH 3 ) 3 , but it was negligible for R=–CH 3 . The mechanisms of “hot” reactions and excess energy relaxation are discussed. - Highlights: ► Radiolysis of bifunctional organic compounds and alkynes. ► Dependence of “hot” fragmentation probability from molecular structure. ► Ions of bifunctional compounds are less stable than those of monofunctional ones. ► Alkynes are rather stable to “hot” fragmentation.

Standard echocardiography versus handheld echocardiography for the detection of subclinical rheumatic heart disease: protocol for a systematic review.

Science.gov (United States)

Telford, Lisa H; Abdullahi, Leila H; Ochodo, Eleanor A; Zühlke, Liesl J; Engel, Mark E

2018-02-10

Rheumatic heart disease (RHD) is a preventable and treatable chronic condition which persists in many developing countries largely affecting impoverished populations. Handheld echocardiography presents an opportunity to address the need for more cost-effective methods of diagnosing RHD in developing countries, where the disease continues to carry high rates of morbidity and mortality. Preliminary studies have demonstrated moderate sensitivity as well as high specificity and diagnostic odds for detecting RHD in asymptomatic patients. We describe a protocol for a systematic review on the diagnostic performance of handheld echocardiography compared to standard echocardiography using the 2012 World Heart Federation criteria for diagnosing subclinical RHD. Electronic databases including PubMed, Scopus, Web of Science and EBSCOhost as well as reference lists and citations of relevant articles will be searched from 2012 to date using a predefined strategy incorporating a combination of Medical Subject Heading terms and keywords. The methodological validity and quality of studies deemed eligible for inclusion will be assessed against review specific Quality Assessment of Diagnostic Accuracy Studies 2 criteria and information on metrics of diagnostic accuracy and demographics extracted. Forest plots of sensitivity and specificity as well as scatter plots in receiver operating characteristic (ROC) space will be used to investigate heterogeneity. If possible, a meta-analysis will be conducted to produce summary results of sensitivity and specificity using the Hierarchical Summary ROC method. In addition, a sensitivity analysis will be conducted to investigate the effect of studies with a high risk of bias. Ethics approval is not required for this systematic review of previously published literature. The planned review will provide a summary of the diagnostic accuracy of handheld echocardiography. Results may feed into evidence-based guidelines and should the findings of this

Detection, Characterization, and Biological Effect of Quorum-Sensing Signaling Molecules in Peanut-Nodulating Bradyrhizobia

Directory of Open Access Journals (Sweden)

Walter Giordano

2012-03-01

Full Text Available Bacteria of the genus Bradyrhizobium are able to establish a symbiotic relationship with peanut (Arachis hypogaea root cells and to fix atmospheric nitrogen by converting it to nitrogenous compounds. Quorum sensing (QS is a cell-cell communication mechanism employed by a variety of bacterial species to coordinate behavior at a community level through regulation of gene expression. The QS process depends on bacterial production of various signaling molecules, among which the N-acylhomoserine lactones (AHLs are most commonly used by Gram-negative bacteria. Some previous reports have shown the production of QS signaling molecules by various rhizobia, but little is known regarding mechanisms of communication among peanut-nodulating strains. The aims of this study were to identify and characterize QS signals produced by peanut-nodulating bradyrhizobial strains and to evaluate their effects on processes related to cell interaction. Detection of AHLs in 53 rhizobial strains was performed using the biosensor strains Agrobacterium tumefaciens NTL4 (pZLR4 and Chromobacterium violaceum CV026 for AHLs with long and short acyl chains, respectively. None of the strains screened were found to produce AHLs with short acyl chains, but 14 strains produced AHLs with long acyl chains. These 14 AHL-producing strains were further studied by quantification of β-galactosidase activity levels (AHL-like inducer activity in NTL4 (pZLR4. Strains displaying moderate to high levels of AHL-like inducer activity were subjected to chemical identification of signaling molecules by high-performance liquid chromatography coupled to mass spectrometry (LC-MS/MS. For each AHL-producing strain, we found at least four different AHLs, corresponding to N-hexanoyl-DL-homoserine lactone (C6, N-(3-oxodecanoyl-L-homoserine lactone (3OC10, N-(3-oxododecanoyl-L-homoserine lactone (3OC12, and N-(3-oxotetradecanoyl-L-homoserine lactone (3OC14. Biological roles of 3OC10, 3OC12, and 3OC14 AHLs

Radiation-induced transformations of isolated organic molecules in solid rare gas matrices

International Nuclear Information System (INIS)

Feldman, V.I.

1998-01-01

Complete text of publication follows. The studies of radiation-chemical behaviour of isolated organic molecules in rigid inert media are of considerable interest for radiation chemistry and general structural chemistry. Previous efforts were limited to the ESR studies of radicals resulting from some small hydrocarbon molecules in frozen rare gas solutions. Recently, we developed an approach to the radiation chemistry of isolated organic molecules using classic matrix isolation procedure for sample preparation and a combination of ESR and IR spectroscopy for characterization of paramagnetic and diamagnetic species resulting form electron irradiation or organic molecules in solid rare gas matrices at 10-15 K. The results obtained reveal high efficiency of energy transfer from rare gas matrix to organic molecules. The total radiation-chemical yields of degradation of organic molecules in argon and xenon matrices were measured directly by IR spectroscopy. The studies of the effect of electron scavengers on the radiolysis of organic molecules in solid rare gases show that the main primary process is positive hole transfer from matrix to additive molecule. ESR spectra of a number of radical cations (alkanes, ethers, arenes) were first characterized in a low-disturbing environment. It was found that the electronic characteristics (IP, polarizability) of the matrix used had crucial effect on trapping and degradation of primary organic radical cations. Using matrices with various IP provides an unique possibility to examine the chemical meaning of excess energy resulting from exothermic positive hole transfer, that is, to follow the fate of excited cations in condensed phase

Epidemiology, health systems and stakeholders in rheumatic heart disease in Africa: a systematic review protocol.

Science.gov (United States)

Moloi, Annesinah Hlengiwe; Watkins, David; Engel, Mark E; Mall, Sumaya; Zühlke, Liesl

2016-05-20

Rheumatic heart disease (RHD) is a chronic disease affecting the heart valves, secondary to group A streptococcal infection (GAS) and subsequent acute rheumatic fever (ARF). However, RHD cure and preventative measures are inextricably linked with socioeconomic development, as the disease mainly affects children and young adults living in poverty. In order to address RHD, public health officials and health policymakers require up-to-date knowledge on the epidemiology of GAS, ARF and RHD, as well as the existing enablers and gaps in delivery of evidence-based care for these conditions. We propose to conduct a systematic review to assess the literature comprehensively, synthesising all existing quantitative and qualitative data relating to RHD in Africa. We plan to conduct a comprehensive literature search using a number of databases and reference lists of relevant articles published from January 1995 to December 2015. Two evaluators will independently review and extract data from each article. Additionally, we will assess overall study quality and risk of bias, using the Newcastle-Ottawa Scale and the Critical Appraisal Skills Programme criteria for quantitative and qualitative studies, respectively. We will meta-analyse estimates of prevalence, incidence, case fatality and mortality for each of the conditions separately for each country. Qualitative meta-analysis will be conducted for facilitators and barriers in RHD health access. Lastly, we will create a list of key stakeholders. This protocol is registered in the PROSPERO International Prospective Register of systematic reviews, registration number CRD42016032852. The information provided by this review will inform and assist relevant stakeholders in identifying key areas of intervention, and designing and implementing evidence-based programmes and policies at the local and regional level. With slight modifications (ie, to the country terms in the search strategy), this protocol can be used as part of a needs

Diffusion and infrared properties of molecules in ice mantles

International Nuclear Information System (INIS)

Schmitt, B.; Grim, R.; Greenberg, J.M.

1989-01-01

Within dense molecular clouds the formation of frozen icy mantles on interstellar dust grains is thought to be the result of various growth conditions. The molecules, which make up the ice mantles are probably completely mixed. To study the physical properties of such ice mixtures the experiments were performed on the evaporation processes and on the spectroscopic properties of CO, CO2, and CH4 in water rich ices. The decrease in concentration of volatile molecules in ice samples deposited at 10 K and subsequently heated is found to occur essentially in two steps. The first one, corresponding to an evaporation of part of the volatile molecules, starts at about 25 K for CO, 32 K for CH4, and 70 K for CO2. During the crystallization of H2O ice at temperatures greater than 120 K a second evaporation occurs leading to the complete disappearance of the volatile molecules in the solid phase. The main astrophysical implications of the diffusion and spectroscopic behaviors are presented. The possible effects of a heating source on the fraction of volatile molecules, such as CO trapped in grain mantles, are discussed

Small molecule screening identifies targetable zebrafish pigmentation pathways

DEFF Research Database (Denmark)

Colanesi, Sarah; Taylor, Kerrie L; Temperley, Nicholas D

2012-01-01

Small molecules complement genetic mutants and can be used to probe pigment cell biology by inhibiting specific proteins or pathways. Here, we present the results of a screen of active compounds for those that affect the processes of melanocyte and iridophore development in zebrafish and investig......Small molecules complement genetic mutants and can be used to probe pigment cell biology by inhibiting specific proteins or pathways. Here, we present the results of a screen of active compounds for those that affect the processes of melanocyte and iridophore development in zebrafish...... and investigate the effects of a few of these compounds in further detail. We identified and confirmed 57 compounds that altered pigment cell patterning, number, survival, or differentiation. Additional tissue targets and toxicity of small molecules are also discussed. Given that the majority of cell types...

Atlas cross section for scattering of muonic hydrogen atoms on hydrogen isotope molecules

International Nuclear Information System (INIS)

Adamczak, A.; Faifman, M.P.; Ponomarev, L.I.

1996-01-01

The total cross sections of the elastic, spin-flip, and charge-exchange processes for the scattering of muonic hydrogen isotope atoms (pμ, dμ, tμ) in the ground state on the hydrogen isotope molecules (H 2 , D 2 , T 2 , HD, HT, DT) are calculated. The scattering cross sections of muonic hydrogen isotope atoms on hydrogen isotope nuclei obtained earlier in the multichannel adiabatic approach are used in the calculations. Molecular effects (electron screening, rotational and vibrational excitations of target molecules, etc.) are taken into account. The spin effects of the target molecules and of the incident muonic atoms are included. the cross sections are averaged over the Boltzmann distribution of the molecule rotational states and the Maxwellian distribution of the target molecule kinetic energies for temperatures 30, 100, 300, and 1000 K. The cross sections are given for kinetic energies of the incident muonic atoms ranging from 0.001 to 100 eV in the laboratory frame. 45 refs., 6 tabs

Matrix effect on hydrogen-atom tunneling of organic molecules in cryogenic solids

International Nuclear Information System (INIS)

Ichikawa, Tsuneki

2000-01-01

Although the tunneling of atoms through potential energy barriers separating the reactant and reaction systems is not paid much attention in organic reactions, this plays an important role in reactions including the transfer of light atoms. Atomic tunneling is especially important for chemical reactions at low temperatures, since the thermal activation of reactant systems is very slow process in comparison with the tunneling. One of the typical reactions of atomic tunneling is hydrogen-atom abstraction from alkanes in cryogenic solids exposed to high-energy radiation. Irradiation of alkane molecules causes the homolytic cleavage of C-H bonds, which results in the pairwise formation of free hydrogen atoms and organic free radicals. Since the activation energies for the abstraction of hydrogen atoms from alkane molecules by free hydrogen atoms are higher than 5 kcal/mol, the lifetime of free hydrogen atoms at 77 K is estimated from the Arrhenius equation of k=vexp(-E a /RT) to be longer than 10 hrs. However, except for solid methane, free hydrogen atoms immediately convert to alkyl radicals even at 4.2 K by hydrogen-atom tunneling from alkane molecules to the free hydrogen atoms. The rate of hydrogen atom tunneling does not necessary increase with decreasing activation energy or the peak height of the potential energy barrier preventing the tunneling. Although the activation energy is the lowest at the tertiary carbon of alkanes, hydrogen atom tunneling from branched alkanes with tertiary carbon at the antepenultimate position of the carbon skeleton is the fastest at the secondary penultimate carbon. Based on our experimental results, we have proposed that the peculiarity of the hydrogen-atom abstraction in cryogenic solids comes from the steric hindrance by matrix molecules to the deformation of alkane molecules from the initial sp 3 to the final sp 2 configurations. The steric hindrance causes the increase of the height of the potential energy barrier for the

Short-term administration of small molecule phenamil induced a protracted osteogenic effect on osteoblast-like MC3T3-E1 cells.

Science.gov (United States)

Lo, Kevin W-H; Kan, Ho Man; Laurencin, Cato T

2016-06-01

Sustained administration (21-day treatment) of the small molecule phenamil has been proposed as an alternative osteogenic factor when used in conjunction with a biodegradable scaffold for in vitro osteogenesis. While promising, the major issue associated with small molecules is non-specific cytotoxicity. The aim of this study was to minimize the side-effects from small-molecule drugs by reducing the frequency of administration. Toward this goal, we investigated whether a shorter phenamil treatment is sufficient to induce in vitro osteogenesis. We compared the effects of short-term (12 h) and continuous treatments of phenamil on osteoblastic differentiation and mineralization. Alkaline phosphatase (ALP) and osteopontin (OPN) activity were used as markers for osteoblastic differentiation. Measurement of the calcium content of the extracellular matrix was used as the hallmark for in vitro bone formation after 21 days of culture. Our findings revealed that both short and continuous phenamil treatment triggers osteoblastic differentiation and mineralization of MC3T3-E1 cells on a biodegradable polymeric scaffold composed of polylactic-co-glycolic acid (PLAGA) at the same time points. In addition, in order to fabricate a phenamil-loaded PLAGA scaffold, the small molecule phenamil was physically absorbed onto the surface of scaffolds and the bioactivity of the loaded scaffolds was evaluated. Furthermore, biochemical analysis indicated that short phenamil treatment of cells was accompanied by upregulation in protein expression of integrin α5, p125(FAK) and phosphorylation of CREB. These effects may contribute to the downstream signalling cascade necessary for osteogenesis, and such responses may account for our observed protracted osteogenic differentiation in vitro. Copyright © 2013 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Neutral molecules in tokamak edge plasma - role of vibrationally excited hydrogen molecules

International Nuclear Information System (INIS)

Cadez, I.; Cercek, M.; Pelicon, P.; Razpet, A.

2003-01-01

The role of neutral molecules in edge plasma is discussed with special emphasis on the vibrationally excited hydrogen. Neutral molecules are formed mostly by surface processes on the walls and then released to the edge plasma where they take part in volumetric reactions with other particles. Typically these molecules are formed in excited states and data are needed for their reactions on the wall and in the volume. Processes in edge plasma determine particle and energy flux what is especially critical issue in tokamak divertor region. Various cross sections and reaction rates are needed for modelling edge plasma and its interaction with walls. (author)

Surface functionalization of aluminosilicate nanotubes with organic molecules

Directory of Open Access Journals (Sweden)

Wei Ma

2012-02-01

Full Text Available The surface functionalization of inorganic nanostructures is an effective approach for enriching the potential applications of existing nanomaterials. Inorganic nanotubes attract great research interest due to their one-dimensional structure and reactive surfaces. In this review paper, recent developments in surface functionalization of an aluminosilicate nanotube, “imogolite”, are introduced. The functionalization processes are based on the robust affinity between phosphate groups of organic molecules and the aluminol (AlOH surface of imogolite nanotubes. An aqueous modification process employing a water soluble ammonium salt of alkyl phosphate led to chemisorption of molecules on imogolite at the nanotube level. Polymer-chain-grafted imogolite nanotubes were prepared through surface-initiated polymerization. In addition, the assembly of conjugated molecules, 2-(5’’-hexyl-2,2’:5’,2’’-terthiophen-5-ylethylphosphonic acid (HT3P and 2-(5’’-hexyl-2,2’:5’,2’’-terthiophen-5-ylethylphosphonic acid 1,1-dioxide (HT3OP, on the imogolite nanotube surface was achieved by introducing a phosphonic acid group to the corresponding molecules. The optical and photophysical properties of these conjugated-molecule-decorated imogolite nanotubes were characterized. Moreover, poly(3-hexylthiophene (P3HT chains were further hybridized with HT3P modified imogolite to form a nanofiber hybrid.

Single Molecule Analysis Research Tool (SMART: an integrated approach for analyzing single molecule data.

Directory of Open Access Journals (Sweden)

Max Greenfeld

Full Text Available Single molecule studies have expanded rapidly over the past decade and have the ability to provide an unprecedented level of understanding of biological systems. A common challenge upon introduction of novel, data-rich approaches is the management, processing, and analysis of the complex data sets that are generated. We provide a standardized approach for analyzing these data in the freely available software package SMART: Single Molecule Analysis Research Tool. SMART provides a format for organizing and easily accessing single molecule data, a general hidden Markov modeling algorithm for fitting an array of possible models specified by the user, a standardized data structure and graphical user interfaces to streamline the analysis and visualization of data. This approach guides experimental design, facilitating acquisition of the maximal information from single molecule experiments. SMART also provides a standardized format to allow dissemination of single molecule data and transparency in the analysis of reported data.

Encaged molecules in external electric fields: A molecular "tug-of-war"

Science.gov (United States)

Gurav, Nalini D.; Gejji, Shridhar P.; Bartolotti, Libero J.; Pathak, Rajeev K.

2016-08-01

Response of polar molecules CH3OH and H2O2 and a non-polar molecule, CO2, as "guests" encapsulated in the dodecahedral water cage (H2O)20 "host," to an external, perturbative electric field is investigated theoretically. We employ the hybrid density-functionals M06-2X and ωB97X-D incorporating the effects of damped dispersion, in conjunction with the maug-cc-pVTZ basis set, amenable for a hydrogen bonding description. While the host cluster (cage) tends to confine the embedded guest molecule through cooperative hydrogen bonding, the applied electric field tends to rupture the cluster-composite by stretching it; these two competitive effects leading to a molecular "tug-of-war." The composite remains stable up to a maximal sustainable threshold electric field, beyond which, concomitant with the vanishing of the HOMO-LUMO gap, the field wins over and the cluster breaks down. The electric-field effects are gauged in terms of the changes in the molecular geometry of the confined species, interaction energy, molecular electrostatic potential surfaces, and frequency shifts of characteristic normal vibrations in the IR regime. Interestingly, beyond the characteristic threshold electric field, the labile, distorted host cluster fragmentizes, and the guest molecule still tethered to a remnant fragment, an effect attributed to the underlying hydrogen-bonded networks.

Strength of interactions between immobilized dye molecules and sol-gel matrices.

Science.gov (United States)

Ismail, Fanya; Schoenleber, Monika; Mansour, Rolan; Bastani, Behnam; Fielden, Peter; Goddard, Nicholas J

2011-02-21

In this paper we present a new theory to re-examine the immobilization technique of dye doped sol-gel films, define the strength and types of possible bonds between the immobilized molecule and sol-gel glass, and show that the immobilized molecule is not free inside the pores as was previously thought. Immobilizing three different pH sensitive dyes with different size and functional groups inside the same sol-gel films revealed important information about the nature of the interaction between the doped molecule and the sol-gel matrix. The samples were characterized by means of ultraviolet-visible spectrophotometer (UV-VIS), thermal gravimetric analysis (TGA), mercury porosimetry (MP), nuclear magnetic resonance spectroscopy ((29)Si NMR) and field-emission environmental scanning electron microscopy (ESEM-FEG). It was found that the doped molecule itself has a great effect on the strength and types of the bonds. A number of factors were identified, such as number and types of the functional groups, overall charge, size, pK(a) and number of the silanol groups which surround the immobilized molecule. These results were confirmed by the successful immobilization of bromocresol green (BCG) after a completely polymerized sol-gel was made. The sol-gel consisted of 50% tetraethoxysilane (TEOS) and 50% methyltriethoxysilane (MTEOS) (w/w). Moreover, the effect of the immobilized molecule on the structure of the sol-gel was studied by means of a leaky waveguide (LW) mode for doped films made before and after polymerization of the sol-gel.

Kinetic Effects in the Self-Assembly of Pure and Mixed Tetradecyland Octadecylamine Molecules on Mica

Energy Technology Data Exchange (ETDEWEB)

Benitez, J.J.; Salmeron, M.

2005-09-21

The self-assembly of tetradecylamine (C14) and of mixtures of tetradecyl and octadecylamine (C18) molecules from chloroform solutions on mica has been studied using atomic force microscopy(AFM). For pure components self-assembly proceeds more slowly for C14 than for C18. In both cases after equilibrium is reached islands of tilted molecules cover a similar fraction of the surface. Images of films formed by mixtures of molecules acquired before equilibrium is reached (short ripening time at room temperature) show only islands with the height corresponding to C18 with many pores. After a long ripening time, when equilibrium is reached, islands of segregated pure components are formed.

Hiperbilirrubinemia neonatal prolongada devido à associação entre síndrome de Gilbert e doença hemolítica por incompatibilidade RhD Persistent neonatal hyperbilirubinemia resulting from Gilbert's syndrome in association with RhD hemolytic disease

Directory of Open Access Journals (Sweden)

Fernando P. Facchini

2005-10-01

production and a signifiant decrease in its excretion. DESCRIPTION: The third pregnancy of an RhD negative woman. Her first child was normal and delivered to term and did not receive Rhogam. The second pregnancy was problematic due to Rh isoimmunization. She delivered a child to term, who required three exchange transfusions, but died on the 8th day of life. The third child was delivered at term, ORh positive, direct Coombs positive and had stump bilirubin of 6.5 mg/dl and hematocrit at 44%. Five hours after birth the child was jaundiced. Phenobarbital and intensive phototherapy were introduced. Hyperbilirubinemia was soon controlled, but relapsed whenever phototherapy was discontinued. On the 10th day of life the child received a transfusion for significant anemia. As jaundice persisted to the 13th day, associated Gilbert syndrome was considered and DNA sequence analysis was requested. The test demonstrated a mutant homozygote genotype UDPT1A1[TA]7TAA. Phototherapy remained necessary until the 17th day of life and she was discharged from hospital the following day, after bilirubinemia had been controlled. She returned for follow-up and exhibited normal growth and neurological development. COMMENTS: This case demonstrates the significance of increased bilirubin production/decreased bilirubin excretion causing intense hyperbilirubinemias and, in the abnsence of vigorous treatment, kernicterus. The effectiveness of intense phototherapy has also been demonstrated, reducing the risks of more aggressive treatments such as exchange transfusion. It also provides evidence of the importance of bilirubinemia follow-up until complete resolution.

The effect of the charge density on the dipole moment of diatomic molecules

International Nuclear Information System (INIS)

Rosato, A.; Germano, J.S.E.

1986-01-01

The results of the calculation, using the Variational Cellular Method (VCM), of the electric dipole moment of several diatomic molecules are improved. In previous calculations, the electronic charge density was treated like a spherically symmetric function in the inscribed sphere within each cell and as being the same constant value for all intercellular regions. Since the results obtained with such an approximation have not been satisfactory, an improved approximation for the charge density in the intercellular regions is needed. It is considered that the charge density is still constant outside the inscribed sphere but with different values in each intercellular region. A new expression for the dipole moment is obtained, and applied to the diatomic molecules HF, CO, BF and CS. In addition, the corresponding dipole moment curves, potential energy curves and spectroscopic constants are calculated taking into consideration our approximation and the traditional approximation for the charge density. The results of the two models are compared with each other and with experimental results for all the molecules considered. (Author) [pt

Quantum mechanical computations and spectroscopy: from small rigid molecules in the gas phase to large flexible molecules in solution.

Science.gov (United States)

Barone, Vincenzo; Improta, Roberto; Rega, Nadia

2008-05-01

Interpretation of structural properties and dynamic behavior of molecules in solution is of fundamental importance to understand their stability, chemical reactivity, and catalytic action. While information can be gained, in principle, by a variety of spectroscopic techniques, the interpretation of the rich indirect information that can be inferred from the analysis of experimental spectra is seldom straightforward because of the subtle interplay of several different effects, whose specific role is not easy to separate and evaluate. In such a complex scenario, theoretical studies can be very helpful at two different levels: (i) supporting and complementing experimental results to determine the structure of the target molecule starting from its spectral properties; (ii) dissecting and evaluating the role of different effects in determining the observed spectroscopic properties. This is the reason why computational spectroscopy is rapidly evolving from a highly specialized research field into a versatile and widespread tool for the assignment of experimental spectra and their interpretation in terms of chemical physical effects. In such a situation, it becomes important that both computationally and experimentally oriented chemists are aware that new methodological advances and integrated computational strategies are available, providing reliable estimates of fundamental spectral parameters not only for relatively small molecules in the gas phase but also for large and flexible molecules in condensed phases. In this Account, we review the most significant methodological contributions from our research group in this field, and by exploiting some recent results of their application to the computation of IR, UV-vis, NMR, and EPR spectral parameters, we discuss the microscopic mechanisms underlying solvent and vibrational effects on the spectral parameters. After reporting some recent achievements for the study of excited states by first principle quantum mechanical

Interaction of spin and vibrations in transport through single-molecule magnets.

Science.gov (United States)

May, Falk; Wegewijs, Maarten R; Hofstetter, Walter

2011-01-01

We study electron transport through a single-molecule magnet (SMM) and the interplay of its anisotropic spin with quantized vibrational distortions of the molecule. Based on numerical renormalization group calculations we show that, despite the longitudinal anisotropy barrier and small transverse anisotropy, vibrational fluctuations can induce quantum spin-tunneling (QST) and a QST-Kondo effect. The interplay of spin scattering, QST and molecular vibrations can strongly enhance the Kondo effect and induce an anomalous magnetic field dependence of vibrational Kondo side-bands.

Exotic helium molecules

International Nuclear Information System (INIS)

Portier, M.

2007-12-01

We study the photo-association of an ultracold cloud of magnetically trapped helium atoms: pairs of colliding atoms interact with one or two laser fields to produce a purely long range 4 He 2 (2 3 S 1 -2 3 P 0 ) molecule, or a 4 He 2 (2 3 S 1 -2 3 S 1 ) long range molecule. Light shifts in one photon photo-association spectra are measured and studied as a function of the laser polarization and intensity, and the vibrational state of the excited molecule. They result from the light-induced coupling between the excited molecule, and bound and scattering states of the interaction between two metastable atoms. Their analysis leads to the determination of the scattering length a = (7.2 ± 0.6) ruling collisions between spin polarized atoms. The two photon photo-association spectra show evidence of the production of polarized, long-range 4 He 2 (2 3 S 1 -2 3 S 1 ) molecules. They are said to be exotic as they are made of two metastable atoms, each one carrying a enough energy to ionize the other. The corresponding lineshapes are calculated and decomposed in sums and products of Breit-Wigner and Fano profiles associated to one and two photon processes. The experimental spectra are fit, and an intrinsic lifetime τ = (1.4 ± 0.3) μs is deduced. It is checked whether this lifetime could be limited by spin-dipole induced Penning autoionization. This interpretation requires that there is a quasi-bound state close to the dissociation threshold in the singlet interaction potential between metastable helium atoms for the theory to match the experiment. (author)

Cold guided beams of polar molecules

International Nuclear Information System (INIS)

Motsch, Michael

2010-01-01

This thesis reports on experiments characterizing cold guided beams of polar molecules which are produced by electrostatic velocity filtering. This filtering method exploits the interaction between the polar molecules and the electric field provided by an electrostatic quadrupole guide to extract efficiently the slow molecules from a thermal reservoir. For molecules with large and linear Stark shifts such as deuterated ammonia (ND 3 ) or formaldehyde (H 2 CO), fluxes of guided molecules of 10 10 -10 11 molecules/s are produced. The velocities of the molecules in these beams are in the range of 10-200 m/s and correspond to typical translational temperatures of a few Kelvin. The maximum velocity of the guided molecules depends on the Stark shift, the molecular mass, the geometry of the guide, and the applied electrode voltage. Although the source is operated in the near-effusive regime, the number density of the slowest molecules is sensitive to collisions. A theoretical model, taking into account this velocity-dependent collisional loss of molecules in the vicinity of the nozzle, reproduces the density of the guided molecules over a wide pressure range. A careful adjustment of pressure allows an increase in the total number of molecules, whilst yet minimizing losses due to collisions of the sought-for slow molecules. This is an important issue for future applications. Electrostatic velocity filtering is suited for different molecular species. This is demonstrated by producing cold guided beams of the water isotopologs H 2 O, D 2 O, and HDO. Although these are chemically similar, they show linear and quadratic Stark shifts, respectively, when exposed to external electric fields. As a result, the flux of HDO is larger by one order of magnitude, and the flux of the individual isotopologs shows a characteristic dependence on the guiding electric field. The internal-state distribution of guided molecules is studied with a newly developed diagnostic method: depletion

Lessons learned from mice deficient in lectin complement pathway molecules

DEFF Research Database (Denmark)

Genster, Ninette; Takahashi, Minoru; Sekine, Hideharu

2014-01-01

in turn activate downstream complement components, ultimately leading to elimination of the pathogen. Mice deficient in the key molecules of lectin pathway of complement have been generated in order to build knowledge of the molecular mechanisms of the lectin pathway in health and disease. Despite......The lectin pathway of the complement system is initiated when the pattern-recognition molecules, mannose-binding lectin (MBL), ficolins or collectin-11, bind to invading pathogens or damaged host cells. This leads to activation of MBL/ficolin/collectin-11 associated serine proteases (MASPs), which...... differences in the genetic arrangements of murine and human orthologues of lectin pathway molecules, the knockout mice have proven to be valuable models to explore the effect of deficiency states in humans. In addition, new insight and unexpected findings on the diverse roles of lectin pathway molecules...

Polarization dependent effects in photo-fragmentation dynamics of free molecules

International Nuclear Information System (INIS)

Mocellin, A.; Marinho, R.R.T.; Coutinho, L.H.; Burmeister, F.; Wiesner, K.; Naves de Brito, A.

2003-01-01

We present multicoincidence spectra of nitrogen, formic acid and methyl methacrylate. We demonstrate how to probe the local symmetry of molecular orbitals from molecules core excited with linearly polarized synchrotron radiation. The intensity distribution of the photoelectron photo-ion photo-ion coincidence (PEPIPICO) spectrum reflects the selectivity and localization of core excitation by polarized light. By simulating the spectra the angular dependence of the fragmentation is determined

Polarization dependent effects in photo-fragmentation dynamics of free molecules

Energy Technology Data Exchange (ETDEWEB)

Mocellin, A.; Marinho, R.R.T.; Coutinho, L.H.; Burmeister, F.; Wiesner, K.; Naves de Brito, A

2003-04-01

We present multicoincidence spectra of nitrogen, formic acid and methyl methacrylate. We demonstrate how to probe the local symmetry of molecular orbitals from molecules core excited with linearly polarized synchrotron radiation. The intensity distribution of the photoelectron photo-ion photo-ion coincidence (PEPIPICO) spectrum reflects the selectivity and localization of core excitation by polarized light. By simulating the spectra the angular dependence of the fragmentation is determined.

[Innovative application of small molecules to influence -pathogenicity of dental plaque].

Science.gov (United States)

Janus, M M; Volgenant, C M C; Krom, B P

2018-05-01

Current preventive measures against infectious oral diseases are mainly focussed on plaque removal and promoting a healthy lifestyle. This in vitro study investigated a third preventive method: maintaining healthy dental plaque with the use of small molecules. As a model of dental plaque, in vitro biofilms were cultivated under conditions that induce pathogenic characteristics. The effect of erythritol and other small molecules on the pathogenic characteristics and bacterial composition of the biofilm was evaluated. The artificial sweetener erythritol and the molecule 3-Oxo-N-(2-oxycyclohexyl)dodecanamide (3-Oxo-N) had no clinically relevant effect on total biofilm formation. Erythritol did, however, lower the gingivitis related protease activity of the biofilm, while 3-Oxo-N blocked the caries related lactic acid accumulation. Furthermore, both substances ensured the biofilm maintained a young, non-pathogenic microbial composition. This shows it is possible to influence the dental plaque in a positive manner in vitro with the help of small molecules. Further research is necessary before this manipulation of dental plaque can be applied.

Many-spin effects and tunneling splittings in Mn12 magnetic molecules

NARCIS (Netherlands)

Raedt, H.A. De; Hams, A.H.; Dobrovitski, V.V.; Al-Saqer, M.; Katsnelson, M.I.; Harmon, B.N.

2002-01-01

We calculate the tunneling splittings in a Mn12 magnetic molecule taking into account its internal many-spin structure. We discuss the precision and reliability of these calculations and show that restricting the basis (limiting the number of excitations taken into account) may lead to significant

The effect of Atorvastatin therapy tumour necrosis factor- and vascular adhesion molecules in patients with type 2 diabetes mellitus with no prior history of coronary heart disease

NARCIS (Netherlands)

Soedamah-Muthu, S.S.; Charlton-Menys, V.; Bao, W.; Schalkwijk, C.G.; Stehouwer, C.D.A.; Colhoun, H.M.; Betteridge, D.J.; Durrington, P.; Hitman, G.; Neil, H.A.W.; Livingstone, S.J.; Fuller, J.H.; DeMicco, D.A.; Preston, G.M.

2011-01-01

We examined the effect of atorvastatin (and placebo) on tumour necrosis factor (TNF)a, soluble vascular cell adhesion molecule-1 (sVCAM-1) and soluble intercellular cell adhesion molecule-1 (sICAM-1) in patients with type 2 diabetes without prior cardiovascular disease (CVD) and investigated whether

Molecule of the Month

Indian Academy of Sciences (India)

Atoms in a molecule generally prefer, particularly among the neighbouring ones, certain optimmn geometrical relationships. These are manifested in specific ranges of bond lengths, bond angles, torsion angles etc. As it always happens, chemists are interested in making molecules where these 'standard relationships' are ...

Influence of vibrations and rotations of diatomic molecules on their physical properties: II. Refractive index, reactivity and diffusion coefficients

International Nuclear Information System (INIS)

Sharipov, Alexander S; Loukhovitski, Boris I; Starik, Alexander M

2016-01-01

The influence of the excitation of vibrational and rotational states of diatomic molecules (H 2 , N 2 , O 2 , NO, OH, CO, CH, HF and HCl) on refractive index, reactivity and transport coefficients was analyzed by using ab initio calculated data on the effective state-specific dipole moment and static polarizability obtained in the preceding paper of the present series. It has been revealed that, for non-polar molecules, the excitation both of vibrational and rotational degrees of freedom increases the averaged polarizability and, as a consequence, the refractive index. Meanwhile, for polar molecules, the effect of molecule excitation is more complex: it can either increase or decrease the refractive index. It was also shown that the excitation of molecules slightly influences the rate constants of barrierless chemical reactions between neutral particles; whereas, for ion–molecule reactions, this effect can be more pronounced. Analysis of the variation of diffusion coefficients, taking into account the effect of molecule excitation both on the collision diameter and on the well depth of intermolecular potential, exhibited that, for non-polar molecules, the effect associated with the change of collision diameter prevails. However, for polar molecules, the effect of the excitation of vibrational states on the well depth of intermolecular potential can compensate or even exceed the decrease of diffusion coefficient due to the averaged collision diameter rise. (paper)

Dissociation and decay of ultracold sodium molecules

International Nuclear Information System (INIS)

Mukaiyama, T.; Abo-Shaeer, J.R.; Xu, K.; Chin, J.K.; Ketterle, W.

2004-01-01

The dissociation of ultracold molecules was studied by ramping an external magnetic field through a Feshbach resonance. The observed dissociation energies directly yielded the strength of the atom-molecule coupling. They showed nonlinear dependence on the ramp speed. This was explained by a Wigner threshold law which predicts that the decay rate of the molecules above threshold increases with the density of states. In addition, inelastic molecule-molecule and molecule-atom collisions were characterized

Analytical calculation of spin tunneling effect in single molecule magnet Fe8 with considering quadrupole excitation

OpenAIRE

Y Yousefi; H Fakhari; K Muminov; M R Benam

2018-01-01

Spin tunneling effect in Single Molecule Magnet Fe8 is studied by instanton calculation technique using SU(3) generalized spin coherent state in real parameter as a trial function. For this SMM, tunnel splitting arises due to the presence of a Berry like phase in action, which causes interference between tunneling trajectories (instantons). For this SMM, it is established that the use of quadrupole excitation (g dependence) changes not only the location of the quenching points, but also the n...

Solvent additive effects on small molecule crystallization in bulk heterojunction solar cells probed during spin casting

KAUST Repository

Pérez, Louis A.

2013-09-04

Solvent additive processing can lead to drastic improvements in the power conversion efficiency (PCE) in solution processable small molecule (SPSM) bulk heterojunction solar cells. In situ grazing incidence wide-angle X-ray scattering is used to investigate the kinetics of crystallite formation during and shortly after spin casting. The additive is shown to have a complex effect on structural evolution invoking polymorphism and enhanced crystalline quality of the donor SPSM. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solvent additive effects on small molecule crystallization in bulk heterojunction solar cells probed during spin casting

KAUST Repository

Pé rez, Louis A.; Chou, Kang Wei; Love, John A.; Van Der Poll, Thomas S.; Smilgies, Detlef Matthias; Nguyen, Thuc Quyen; Krä mer, Edward J.; Amassian, Aram; Bazan, Guillermo C.

2013-01-01

Solvent additive processing can lead to drastic improvements in the power conversion efficiency (PCE) in solution processable small molecule (SPSM) bulk heterojunction solar cells. In situ grazing incidence wide-angle X-ray scattering is used to investigate the kinetics of crystallite formation during and shortly after spin casting. The additive is shown to have a complex effect on structural evolution invoking polymorphism and enhanced crystalline quality of the donor SPSM. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Single-molecule electronics: Cooling individual vibrational modes by the tunneling current.

Science.gov (United States)

Lykkebo, Jacob; Romano, Giuseppe; Gagliardi, Alessio; Pecchia, Alessandro; Solomon, Gemma C

2016-03-21

Electronic devices composed of single molecules constitute the ultimate limit in the continued downscaling of electronic components. A key challenge for single-molecule electronics is to control the temperature of these junctions. Controlling heating and cooling effects in individual vibrational modes can, in principle, be utilized to increase stability of single-molecule junctions under bias, to pump energy into particular vibrational modes to perform current-induced reactions, or to increase the resolution in inelastic electron tunneling spectroscopy by controlling the life-times of phonons in a molecule by suppressing absorption and external dissipation processes. Under bias the current and the molecule exchange energy, which typically results in heating of the molecule. However, the opposite process is also possible, where energy is extracted from the molecule by the tunneling current. Designing a molecular "heat sink" where a particular vibrational mode funnels heat out of the molecule and into the leads would be very desirable. It is even possible to imagine how the vibrational energy of the other vibrational modes could be funneled into the "cooling mode," given the right molecular design. Previous efforts to understand heating and cooling mechanisms in single molecule junctions have primarily been concerned with small models, where it is unclear which molecular systems they correspond to. In this paper, our focus is on suppressing heating and obtaining current-induced cooling in certain vibrational modes. Strategies for cooling vibrational modes in single-molecule junctions are presented, together with atomistic calculations based on those strategies. Cooling and reduced heating are observed for two different cooling schemes in calculations of atomistic single-molecule junctions.

Vibrational-rotational relaxation of the simplest hydrogen-containing molecules (review)

International Nuclear Information System (INIS)

Molevich, N.E.; Oraevskii, A.N.

1987-01-01

In connection with the development of chemical lasers much attention is now devoted to the study of kinetic processes is gaseous mixtures containing the hydrogen halides. Vibrational relaxation of molecules if primarily studied without specifying its relation to the rational levels. Rotational relaxation is regarded a priori as faster than vibrational relaxation, so that the population of the rotational levels is assumed to be in equilibrium. This approach to the relaxation of hydrogen halide molecules (and other diatomic hydrogen-containing molecules), however, is unable to explain satisfactorily the results of the papers discussed below. An analysis of the data obtained in these papers leads to the conclusion that the general picture of relaxation in diatomic hydrogen-containing molecules must be viewed as a unified process of vibrational and rotational relaxation. It is shown that those effects observed during vibrational relaxation of such molecules which are unusual from the standpoint of the theory of vibrational-translational relaxation are well explained in terms of intermolecular vibrational-rotational relaxation together with pure rotational relaxation

Single-Molecule Interfacial Electron Transfer

Energy Technology Data Exchange (ETDEWEB)

Lu, H. Peter [Bowling Green State Univ., Bowling Green, OH (United States). Dept. of Chemistry and Center for Photochemical Sciences

2017-11-28

This project is focused on the use of single-molecule high spatial and temporal resolved techniques to study molecular dynamics in condensed phase and at interfaces, especially, the complex reaction dynamics associated with electron and energy transfer rate processes. The complexity and inhomogeneity of the interfacial ET dynamics often present a major challenge for a molecular level comprehension of the intrinsically complex systems, which calls for both higher spatial and temporal resolutions at ultimate single-molecule and single-particle sensitivities. Combined single-molecule spectroscopy and electrochemical atomic force microscopy approaches are unique for heterogeneous and complex interfacial electron transfer systems because the static and dynamic inhomogeneities can be identified and characterized by studying one molecule at a specific nanoscale surface site at a time. The goal of our project is to integrate and apply these spectroscopic imaging and topographic scanning techniques to measure the energy flow and electron flow between molecules and substrate surfaces as a function of surface site geometry and molecular structure. We have been primarily focusing on studying interfacial electron transfer under ambient condition and electrolyte solution involving both single crystal and colloidal TiO₂ and related substrates. The resulting molecular level understanding of the fundamental interfacial electron transfer processes will be important for developing efficient light harvesting systems and broadly applicable to problems in fundamental chemistry and physics. We have made significant advancement on deciphering the underlying mechanism of the complex and inhomogeneous interfacial electron transfer dynamics in dyesensitized TiO₂ nanoparticle systems that strongly involves with and regulated by molecule-surface interactions. We have studied interfacial electron transfer on TiO₂ nanoparticle surfaces by using ultrafast single-molecule

Study the multi-photon absorption process in two types of molecules

International Nuclear Information System (INIS)

Al-azawi, H.R.

1986-01-01

The aim of the present work was to study the multi-photon absorption process in two types of molecules; spherical top such as SF 6 molecules and assymetric top such as CHOOH and C 2 H 4 molecules. This work also aimed to study the effect of buffer gas pressure (Ar), which is transparent to the infrared (IR) laser on the multiphoton absorption of both types of molecules. A pulsed (TEA) CO 2 laser was used as a source which generates multi-lines in the IR-region of the spectrum and an optoacoustic detector was used to detect the energy absorbed by the molecules. In this study, the relaxation process was found to be faster in the heavy molecules than that in the light ones. A limit in the Ar pressure was observed. Below this limit, the gas acted as an active buffer gas and above it, the multi-photon absorption process was quenched. This work also aimed to study the multi-photon absorption spectrum for the CHOOH molecules in the range (1067-1090 cm -1 ). This spectrum was found to be consistent with the linear absorption spectrum obtained for the same range. The density of the vibrational states as a function of the vibrational energy was studied for the molecules SF 6 , CHOOH and C 2 H 4 . The results were used to interpret (i) the difference in the energy absorbed by difference molecules at the same energy density and (ii) the non-linearity in the multi-photon absorption for CHOOH molecules. 1 tab.; 40 figs.; 70 refs

Enrichment of megabase-sized DNA molecules for single-molecule optical mapping and next-generation sequencing

DEFF Research Database (Denmark)

Łopacińska-Jørgensen, Joanna M; Pedersen, Jonas Nyvold; Bak, Mads

2017-01-01

Next-generation sequencing (NGS) has caused a revolution, yet left a gap: long-range genetic information from native, non-amplified DNA fragments is unavailable. It might be obtained by optical mapping of megabase-sized DNA molecules. Frequently only a specific genomic region is of interest, so......-megabase- to megabase-sized DNA molecules were recovered from the gel and analysed by denaturation-renaturation optical mapping. Size-selected molecules from the same gel were sequenced by NGS. The optically mapped molecules and the NGS reads showed enrichment from regions defined by NotI restriction sites. We...... demonstrate that the unannotated genome can be characterized in a locus-specific manner via molecules partially overlapping with the annotated genome. The method is a promising tool for investigation of structural variants in enriched human genomic regions for both research and diagnostic purposes. Our...

Targeting p53 by small molecules in hematological malignancies

OpenAIRE

Saha, Manujendra N; Qiu, Lugui; Chang, Hong

2013-01-01

p53 is a powerful tumor suppressor and is an attractive cancer therapeutic target. A breakthrough in cancer research came from the discovery of the drugs which are capable of reactivating p53 function. Most anti-cancer agents, from traditional chemo- and radiation therapies to more recently developed non-peptide small molecules exert their effects by enhancing the anti-proliferative activities of p53. Small molecules such as nutlin, RITA, and PRIMA-1 that can activate p53 have shown their ant...

Preface: Special Topic on Single-Molecule Biophysics.

Science.gov (United States)

Makarov, Dmitrii E; Schuler, Benjamin

2018-03-28

Single-molecule measurements are now almost routinely used to study biological systems and processes. The scope of this special topic emphasizes the physics side of single-molecule observations, with the goal of highlighting new developments in physical techniques as well as conceptual insights that single-molecule measurements bring to biophysics. This issue also comprises recent advances in theoretical physical models of single-molecule phenomena, interpretation of single-molecule signals, and fundamental areas of statistical mechanics that are related to single-molecule observations. A particular goal is to illustrate the increasing synergy between theory, simulation, and experiment in single-molecule biophysics.

Structural characterization of some substituted azolidine molecules

International Nuclear Information System (INIS)

Andreocci, M.V.; Bossa, M.; Furlani, C.; Mattogno, G.; Zanoni, R.; Consiglio Nazionale delle Ricerche, Rome; Devillanova, F.A.; Verani, G.

1981-01-01

The electronic structure of a series of organic molecules of general formula RN - (CH 2 ) 2 - X - C = Y, which are also of interest in inorganic chemistry because of their properties as ligands towards metals, have been investigated by X-ray photoelectron spectroscopy. The results suggest a general picture of atomic charge distribution within the investigated molecules, and allow an assessment of the effect of the different substituent groups X, Y, R (X = NR', O, S, CH 2 ; Y = O, S, Se; R, R' = H, alkyl) on the electronic structure of the ligands. Satisfactory correlation is found between experimental binding energies and computed CNDO/2 atomic charges, after correction for intramolecular Madelung potentials. (orig.)

Labelled molecules, modern research implements

International Nuclear Information System (INIS)

Pichat, L.; Langourieux, Y.

1974-01-01

Details of the synthesis of carbon 14- and tritium-labelled molecules are examined. Although the methods used are those of classical organic chemistry the preparation of carbon 14-labelled molecules differs in some respects, most noticeably in the use of 14 CO 2 which requires very special handling techniques. For the tritium labelling of organic molecules the methods are somewhat different, very often involving exchange reactions. The following are described in turn: the so-called Wilzbach exchange method; exchange by catalysis in solution; catalytic hydrogenation with tritium; reductions with borotritides. Some applications of labelled molecules in organic chemistry, biochemistry and pharmacology are listed [fr

Possible heterogeneity of centres of binding 1,8-ANS in molecules of oxygenated hemoglobin

International Nuclear Information System (INIS)

Parul', D.A.; Bokut', S.B.; Milyutin, A.A.; Petrov, E.P.; Nemkovich, N.A.; Sobchuk, A.N.; Dzhagarov, B.M.

1999-01-01

Forming of oxygenated hemoglobin is one of effects of ionizing radiation action on organism. It was revealed heterogeneity of centers of binding of 1,8-ANS in intact molecule of oxygenated hemoglobin. Two types of binding centers possible reflect the existence of two regions in protein molecule with different accessibility to molecules of water

Investigation of photobleaching and saturation of single molecules by fluorophore recrossing events

Energy Technology Data Exchange (ETDEWEB)

Burrows, Sean M.; Reif, Randall D. [Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061 (United States); Pappas, Dimitri [Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061 (United States)], E-mail: d.pappas@ttu.edu

2007-08-15

A method for investigation of photobleaching and saturation of single molecules by fluorophore recrossing events in a laser beam is described. The diffraction-limited probe volumes encountered in single-molecule detection (SMD) produce high excitation irradiance, which can decrease available signal. The single molecules of several dyes were detected and the data was used to extract interpeak times above a defined threshold value. The interpeak times revealed the number of fluorophore recrossing events. The number of molecules detected that were within 2 ms of each other represented a molecular recrossing for this work. Calcein, fluorescein and R-phycoerythrin were analyzed and the saturation irradiance and photobleaching effects were determined as a function of irradiance. This approach is simple and it serves as a method of optimizing experimental conditions for single-molecule detection.

Electrochemical Single-Molecule Transistors with Optimized Gate Coupling

DEFF Research Database (Denmark)

Osorio, Henrry M.; Catarelli, Samantha; Cea, Pilar

2015-01-01

Electrochemical gating at the single molecule level of viologen molecular bridges in ionic liquids is examined. Contrary to previous data recorded in aqueous electrolytes, a clear and sharp peak in the single molecule conductance versus electrochemical potential data is obtained in ionic liquids....... These data are rationalized in terms of a two-step electrochemical model for charge transport across the redox bridge. In this model the gate coupling in the ionic liquid is found to be fully effective with a modeled gate coupling parameter, ξ, of unity. This compares to a much lower gate coupling parameter...

Single-molecule conductivity of non-redox and redox molecules at pure and gold-mined Au(111)-electrode surfaces

DEFF Research Database (Denmark)

Zhang, Jingdong; Chi, Qijin; Ulstrup, Jens

The structure, two-dimensional organization, and function of molecules immobilized on solid surfaces can be addressed in a degree of detail that has reached the level of the single-molecule. In this context redox molecules are “smart” molecules adding sophisticated electronic function. Redox meta...

Interaction of spin and vibrations in transport through single-molecule magnets

Directory of Open Access Journals (Sweden)

Falk May

2011-10-01

Full Text Available We study electron transport through a single-molecule magnet (SMM and the interplay of its anisotropic spin with quantized vibrational distortions of the molecule. Based on numerical renormalization group calculations we show that, despite the longitudinal anisotropy barrier and small transverse anisotropy, vibrational fluctuations can induce quantum spin-tunneling (QST and a QST-Kondo effect. The interplay of spin scattering, QST and molecular vibrations can strongly enhance the Kondo effect and induce an anomalous magnetic field dependence of vibrational Kondo side-bands.

Effect of molecular structure on fragmentation of isolated organic molecules in solid rare gas matrices

International Nuclear Information System (INIS)

Kobrazenko, A.V.; Sukhov, F.F.; Orlov, A.Yu.; Kovalev, G.V.; Baranova, I.A.; Feldman, V.I.

2011-01-01

Complete text of publication follows. Elucidation of high-energy reaction pathways in the condensed phase is an important issue for basic understanding of the radiation stability of complex organic molecules. As was shown previously, organic radical cations (RC) may undergo fragmentation or rearrangement in solid matrices due to excess energy. The probability of this process depends on both ionization potential (IP) of the molecule and molecular structure. In the present work we have studied the role of 'hot' ionic reaction channels for RC of some bifunctional compounds and alkynes. The effect of excess energy was simulated by matrix isolation method as described in detail earlier. The formation of fragmentation products was monitored by EPR and FTIR spectroscopy. In the present work it was shown that the RC of bifunctional compounds (CH 3 OCH 2 COCH 3 , CH 3 CO(CH 2 ) n COCH 3 , n 0/2) dissociated efficiently producing · CH 3 radicals upon irradiation in solid argon matrix at T ≤ 16 K. The probability of fragmentation decreases with decrease of excess energy by switching from Ar to Xe. It is worth noting that acetone RC does not show fragmentation under these conditions. Thus, bifunctional molecules were found to be less stable to 'hot' ionic fragmentation in low-temperature solids in comparison with simple prototype carbonyl compounds. In the case of alkynes of the R-C ≡ CH type, a noticeable yield of fragmentation products was observed when R = -C(CH 3 ) 3 , but it was negligible for R = -CH 3 . It means that the presence of triple bond stabilizes the molecular skeleton of linear alkynes toward 'hot' fragmentation, similarly as it was shown for alkenes. The mechanisms of 'hot' reactions and excess energy relaxation are discussed. This work was supported by the Russian Foundation for Basic Research (project 09-03-00848a).

Isonitrile ligand effects on small-molecule-sequestering in bimetalladodecaborane clusters

Czech Academy of Sciences Publication Activity Database

Bould, Jonathan; Londesborough, Michael Geoffrey Stephen; Kennedy, JD.; Macias, R.; Winter, REK.; Císařová, I.; Kubát, Pavel; Lang, Kamil

2013-01-01

Roč. 747, december (2013), s. 76-84 ISSN 0022-328X R&D Projects: GA ČR GAP207/11/1577; GA ČR GAP208/10/1678; GA ČR GAP207/11/0705 Institutional support: RVO:61388980 ; RVO:61388955 Keywords : Metallaboranes * Small molecule * Sequestration * DFT * Isonitrile * Carbon monoxide Subject RIV: CA - Inorganic Chemistry; CF - Physical ; Theoretical Chemistry (UFCH-W) Impact factor: 2.302, year: 2013

The origin of small and large molecule behavior in the vibrational relaxation of highly excited molecules

International Nuclear Information System (INIS)

Gordon, R.J.

1990-01-01

An explanation is proposed for the qualitatively different types of behavior that have been reported for the vibrational relaxation of highly excited diatomic and polyatomic molecules. It is argued that all of the diatomic molecules that have been studied in bulk relax adiabatically at room temperature. In contrast, large polyatomic molecules have low frequency modes which act at ''doorway'' modes for the rest of the molecules, producing an impulsive relaxation mechanism. The theoretical work of Nesbitt and Hynes showed that impulsive collisions result in an exponential decay of the average vibrational energy of a Morse oscillator, whereas adiabatic collisions produce nonexponential power law behavior. We propose that this result explains a large body of data for the vibrational relaxation of small and large molecules

Protection of a PWR nuclear power stations against corrosion using hydrogen molecules to capture oxygen molecules

International Nuclear Information System (INIS)

Nahili, M.

2004-01-01

A protection method for the primary loops metals of nuclear power plants from corrosion was investigated. Hydrogen molecules were added to the primary circuit to eliminate oxygen molecules produced by radiolysis of coolant at the reactor core. The hydrogen molecules were produced by electrolyses of water and then added when the coolant water was passing through the primary coolant circuit. Thermodynamical process and the protection methods from corrosion were discussed, the discussion emphasized on the removal of oxygen molecules as one of the protection methods, and compared with other methods. The amount of hydrogen molecules needed for complete removal of oxygen was estimated in two cases: in the case without passing the water through the oxygen removal system, and in the case of passing water through the system. A pressurized water reactor VVER was chosen to be investigated in this study. The amount of hydrogen molecules was estimated so as to eliminate completely the oxygen molecules from coolant water. The estimated value was found to be less than the permissible range for coolant water for such type of reactors. A simulation study for interaction mechanism between hydrogen and oxygen molecules as water flowing in a tube similar to that of coolant water was performed with different water flow velocities. The interaction between the molecules of hydrogen and oxygen was described. The gas diffusion at the surface of the tube was found to play a major role in the interaction. A mathematical model was found to give full description of the change of oxygen concentration through the tube, as well as, to calculate the length of the tube where the concentration of oxygen reduced to few order of magnitude. (Author)

Newly diagnosed rheumatic heart disease among indigenous populations in the Pacific.

Science.gov (United States)

Mirabel, Mariana; Tafflet, Muriel; Noël, Baptiste; Parks, Tom; Axler, Olivier; Robert, Jacques; Nadra, Marie; Phelippeau, Gwendolyne; Descloux, Elodie; Cazorla, Cécile; Missotte, Isabelle; Gervolino, Shirley; Barguil, Yann; Rouchon, Bernard; Laumond, Sylvie; Jubeau, Thierry; Braunstein, Corinne; Empana, Jean-Philippe; Marijon, Eloi; Jouven, Xavier

2015-12-01

Rheumatic heart disease (RHD) remains the leading acquired heart disease in the young worldwide. We aimed at assessing outcomes and influencing factors in the contemporary era. Hospital-based cohort in a high-income island nation where RHD remains endemic and the population is captive. All patients admitted with newly diagnosed RHD according to World Heart Federation echocardiographic criteria were enrolled (2005-2013). The incidence of major cardiovascular events (MACEs) including heart failure, peripheral embolism, stroke, heart valve intervention and cardiovascular death was calculated, and their determinants identified. Of the 396 patients, 43.9% were male with median age 18 years (IQR 10-40)). 127 (32.1%) patients presented with mild, 131 (33.1%) with moderate and 138 (34.8%) with severe heart valve disease. 205 (51.8%) had features of acute rheumatic fever. 106 (26.8%) presented with at least one MACE. Among the remaining 290 patients, after a median follow-up period of 4.08 (95% CI 1.84 to 6.84) years, 7 patients (2.4%) died and 62 (21.4%) had a first MACE. The annual incidence of first MACE and of heart failure were 59.05‰ (95% CI 44.35 to 73.75) and 29.06‰ (95% CI 19.29 to 38.82), respectively. The severity of RHD at diagnosis (moderate vs mild HR 3.39 (0.95 to 12.12); severe vs mild RHD HR 10.81 (3.11 to 37.62), pdisease and no secondary prophylaxis. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Nuclear fusion rate of the muonic T3 molecule

International Nuclear Information System (INIS)

Faghihi, F.; Eskandari, M. R.

2004-01-01

The ground state binding energy, size and effective nuclear charge of the muonic T 3 molecule are calculated using Born-Oppenheimer adiabatic approximation. The system possesses two minimum positions, one at typically muonic and the second at the atomic distances. A symmetric planar vibrational model between two minima is assumed and the approximated potential are calculated. Moreover, nuclear fusion rate calculations of the short-life molecule is carried out due to the overlap integral of the resonance nuclear compound nucleus and the molecular wave functions

Dust-forming molecules in VY Canis Majoris (and Betelgeuse)

OpenAIRE

Kaminski, T.; Gottlieb, C. A.; Schmidt, M. R.; Patel, N. A.; Young, K. H.; Menten, K. M.; Brunken, S.; Muller, H. S. P.; Winters, J. M.; McCarthy, M. C.

2013-01-01

The formation of inorganic dust in circumstellar environments of evolved stars is poorly understood. Spectra of molecules thought to be most important for the nucleation, i.e. AlO, TiO, and TiO2, have been recently detected in the red supergiant VY CMa. These molecules are effectively formed in VY CMa and the observations suggest that non-equilibrium chemistry must be involved in their formation and nucleation into dust. In addition to exploring the recent observations of VY CMa, we briefly d...

Electron attachment to the phthalide molecule

Energy Technology Data Exchange (ETDEWEB)

Asfandiarov, N. L. [Institute of Molecule and Crystal Physics, Ufa Research Centre, Russian Academy of Sciences, Prospect Oktyabrya 151, 450075 Ufa (Russian Federation); Bashkir State Pedagogical University, Oktyabrskoy Revolutsii St., 3a, 450000 Ufa (Russian Federation); Pshenichnyuk, S. A. [Institute of Molecule and Crystal Physics, Ufa Research Centre, Russian Academy of Sciences, Prospect Oktyabrya 151, 450075 Ufa (Russian Federation); St.-Petersburg State University, Uljanovskaja, 1, 198504 St.-Petersburg (Russian Federation); Vorob’ev, A. S.; Nafikova, E. P. [Institute of Molecule and Crystal Physics, Ufa Research Centre, Russian Academy of Sciences, Prospect Oktyabrya 151, 450075 Ufa (Russian Federation); Lachinov, A. N. [Bashkir State Pedagogical University, Oktyabrskoy Revolutsii St., 3a, 450000 Ufa (Russian Federation); Kraikin, V. A. [Institute of Organic Chemistry, Ufa Research Centre, Russian Academy of Sciences, Prospect Oktyabrya 59, 450075 Ufa (Russian Federation); Modelli, A. [Dipartimento di Chimica “G. Ciamician,” Universitá di Bologna, Via Selmi 2, 40126 Bologna (Italy); Centro Interdipartimentale di Ricerca in Scienze Ambientali (CIRSA), Universitá di Bologna, Via S. Alberto 163, 48123 Ravenna (Italy)

2015-05-07

Phthalide, the simplest chain of conductive polymer thin film, was investigated by means of Electron Transmission Spectroscopy, Negative Ion Mass Spectrometry, and density functional theory quantum chemistry. It has been found that formation of gas-phase long-lived molecular anions of phthalide around 0.7 eV takes place through cleavage of a C–O bond of the pentacyclic ring of the parent molecular anion to give a vibrationally excited (electronically more stable) open-ring molecular anion. The energy of the transition state for ring opening of the parent negative ion is calculated to be 0.65 eV above the neutral ground state of the molecule. The energy (2.64 eV) evaluated for the corresponding transition state in the neutral molecule is much higher, so that the process of electron detachment from the anion must lead to a neutral molecule with its initial pentacyclic structure. The average lifetime of the molecular negative ions formed at an electron energy of 0.75 eV and 80 °C is measured to be about 100 μs. The known switching effect of thin phthalide films could stem from the presence of a similar open/closed transition state also in the polymer.

Effects of alpha-tocopherol on superoxide production and plasma intercellular adhesion molecule-1 and antibodies to oxidized LDL in chronic smokers

NARCIS (Netherlands)

Tits, van L.J.; Waart, de F.; Hak-Lemmers, H.L.M.; Heijst, P.; Graaf, de J.; Demacker, P.N.; Stalenhoef, A.F.

2001-01-01

Antioxidants have been postulated to exert beneficial effects in atherosclerosis. Atherosclerosis is associated with raised plasma levels of soluble intercellular adhesion molecule-1 (sICAM-1) and autoantibodies against oxidized low-density lipoprotein (oxLDL). It is not known whether antioxidants

The effect of CD4 receptor downregulation and its downstream signaling molecules on HIV-1 latency

International Nuclear Information System (INIS)

Kim, Kyung-Chang; Kim, Hyeon Guk; Roh, Tae-Young; Park, Jihwan; Jung, Kyung-Min; Lee, Joo-Shil; Choi, Sang-Yun; Kim, Sung Soon; Choi, Byeong-Sun

2011-01-01

Research highlights: → CD4 receptors were downregulated on the surface of HIV-1 latently infected cells. → CD4 downstream signaling molecules were suppressed in HIV-1 latently infected cells. → HIV-1 progeny can be reactivated by induction of T-cell activation signal molecules. → H3K4me3 and H3K9ac were highly enriched in CD4 downstream signaling molecules. → HIV-1 latency can be maintained by the reduction of downstream signaling molecules. -- Abstract: HIV-1 can establish a latent infection in memory CD4 + T cells to evade the host immune response. CD4 molecules can act not only as the HIV-1 receptor for entry but also as the trigger in an intracellular signaling cascade for T-cell activation and proliferation via protein tyrosine kinases. Novel chronic HIV-1-infected A3.01-derived (NCHA) cells were used to examine the involvement of CD4 downstream signaling in HIV-1 latency. CD4 receptors in NCHA cells were dramatically downregulated on its surface but were slightly decreased in whole-cell lysates. The expression levels of CD4 downstream signaling molecules, including P56 Lck , ZAP-70, LAT, and c-Jun, were sharply decreased in NCHA cells. The lowered histone modifications of H3K4me3 and H3K9ac correlated with the downregulation of P56 Lck , ZAP-70, and LAT in NCHA cells. AP-1 binding activity was also reduced in NCHA cells. LAT and c-Jun suppressed in NCHA cells were highly induced after PMA treatment. In epigenetic analysis, other signal transduction molecules which are associated with active and/or latent HIV-1 infection showed normal states in HIV-1 latently infected cells compared to A3.01 cells. In conclusion, we demonstrated that the HIV-1 latent state is sustained by the reduction of downstream signaling molecules via the downregulation of CD4 and the attenuated activity of transcription factor as AP-1. The HIV-1 latency model via T-cell deactivation may provide some clues for the development of the new antireservoir therapy.

The effect of CD4 receptor downregulation and its downstream signaling molecules on HIV-1 latency

Energy Technology Data Exchange (ETDEWEB)

Kim, Kyung-Chang [National Institute of Health, Chungbuk (Korea, Republic of); School of Life Science and Biotechnology, Korea University, Seoul (Korea, Republic of); Kim, Hyeon Guk [National Institute of Health, Chungbuk (Korea, Republic of); Roh, Tae-Young [Division of Molecular and Life Science, Pohang University of Science and Technology, Pohang, Gyeongbuk (Korea, Republic of); Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang, Gyeongbuk (Korea, Republic of); Park, Jihwan [Division of Molecular and Life Science, Pohang University of Science and Technology, Pohang, Gyeongbuk (Korea, Republic of); Jung, Kyung-Min; Lee, Joo-Shil [National Institute of Health, Chungbuk (Korea, Republic of); Choi, Sang-Yun [School of Life Science and Biotechnology, Korea University, Seoul (Korea, Republic of); Kim, Sung Soon [National Institute of Health, Chungbuk (Korea, Republic of); Choi, Byeong-Sun, E-mail: byeongsun@korea.kr [National Institute of Health, Chungbuk (Korea, Republic of)

2011-01-14

Research highlights: {yields} CD4 receptors were downregulated on the surface of HIV-1 latently infected cells. {yields} CD4 downstream signaling molecules were suppressed in HIV-1 latently infected cells. {yields} HIV-1 progeny can be reactivated by induction of T-cell activation signal molecules. {yields} H3K4me3 and H3K9ac were highly enriched in CD4 downstream signaling molecules. {yields} HIV-1 latency can be maintained by the reduction of downstream signaling molecules. -- Abstract: HIV-1 can establish a latent infection in memory CD4 + T cells to evade the host immune response. CD4 molecules can act not only as the HIV-1 receptor for entry but also as the trigger in an intracellular signaling cascade for T-cell activation and proliferation via protein tyrosine kinases. Novel chronic HIV-1-infected A3.01-derived (NCHA) cells were used to examine the involvement of CD4 downstream signaling in HIV-1 latency. CD4 receptors in NCHA cells were dramatically downregulated on its surface but were slightly decreased in whole-cell lysates. The expression levels of CD4 downstream signaling molecules, including P56{sup Lck}, ZAP-70, LAT, and c-Jun, were sharply decreased in NCHA cells. The lowered histone modifications of H3K4me3 and H3K9ac correlated with the downregulation of P56{sup Lck}, ZAP-70, and LAT in NCHA cells. AP-1 binding activity was also reduced in NCHA cells. LAT and c-Jun suppressed in NCHA cells were highly induced after PMA treatment. In epigenetic analysis, other signal transduction molecules which are associated with active and/or latent HIV-1 infection showed normal states in HIV-1 latently infected cells compared to A3.01 cells. In conclusion, we demonstrated that the HIV-1 latent state is sustained by the reduction of downstream signaling molecules via the downregulation of CD4 and the attenuated activity of transcription factor as AP-1. The HIV-1 latency model via T-cell deactivation may provide some clues for the development of the new

Effect of the moment of inertia of an electron shell on the rotational g factor of a molecule

International Nuclear Information System (INIS)

Rebane, T.K.

1988-01-01

It is noted that electron currents induced by the rotation of a molecule make a contribution not only to the magnetic moment, but also to the angular momentum of a molecule and to its moment of inertia. An improved equation for the rotational g factor of a molecule, allowing for the contribution of electrons to the moment of inertia, is given. The B 1 summation + /sub u/ excited electronic state of the hydrogen molecule is used as an example to show that the electronic contribution to the moment of inertia amounts to 0.3 to 0.5% (for H 2 and D 2 molecules, respectively) of the value of the nuclear contribution, and its consideration in calculations of g factors is obligatory

The ability of left- and right-hemisphere damaged individuals to produce prosodic cues to disambiguate Korean idiomatic sentences

Directory of Open Access Journals (Sweden)

Seung-Yun Yang

2014-05-01

Three speech language pathologists with training in phonetics participated as raters for vocal qualities. Nasality was significantly salient vocal quality of idiomatic utterances. Conclusion The findings support that (1 LHD negatively affected the production of durational cues and RHD negatively affected the production of fundamental frequency cues in idiomatic-literal contrasts; (2 healthy listeners successfully identified idiomatic and literal versions of ambiguous sentences produced by healthy speakers but not by RHD speakers; (3 Productions in brain-damaged participants approximated HC’s measures in the repetition tasks, but not in the elicitation tasks; (4 Nasal voice quality was judged to be associated with idiomatic utterances in all groups of participants. Findings agree with previous studies indicating HC’s abilities to discriminate literal versus idiomatic meanings in ditropically ambiguous idioms, as well as deficient processing of pitch production and impaired pragmatic ability in RHD.

Organic Semiconductor-Containing Supramolecules: Effect of Small Molecule Crystallization and Molecular Packing

KAUST Repository

Rancatore, Benjamin J.; Kim, BongSoo; Mauldin, Clayton E.; Frechet, Jean; Xu, Ting

2016-01-01

on these highly crystalline molecules differs from their less crystalline counterparts. Here, two families of organic semiconductor SMs are investigated, where the composition of the crystalline core, the location (side- vs end-functionalization) of the alkyl

The Relation between Structure and Quantum Interference in Single Molecule Junctions

DEFF Research Database (Denmark)

Markussen, Troels; Stadler, Robert; Thygesen, Kristian Sommer

2010-01-01

Quantum interference (QI) of electron pathways has recently attracted increased interest as an enabling tool for single-molecule electronic devices. Although various molecular systems have been shown to exhibit QI effects and a number of methods have been proposed for its analysis, simple...... guidelines linking the molecular structure to QI effects in the phase-coherent transport regime have until now been lacking. In the present work we demonstrate that QI in aromatic molecules is intimately related to the topology of the molecule’s π system and establish a simple graphical scheme to predict...

Molecule of the Month

Indian Academy of Sciences (India)

Cyclo bu tadiene (1) has been one of the most popular molecules for experimentalists and theoreticians. This molecule is unstable as . it is antiaromatic ( 4,n electrons in a cyclic array). Even though some highly substituted cyclobutadienes, for example, compound 2 and the Fe(CO)3 complex of cyclobutadiene (3) are ...

Effect of hydration on the organo-noble gas molecule HKrCCH: role of krypton in the stabilization of hydrated HKrCCH complexes.

Science.gov (United States)

Biswas, Biswajit; Singh, Prashant Chandra

2015-11-11

The effect of hydration on the fluorine free organo-noble gas compound HKrCCH and the role of krypton in the stabilization of the hydrated HKrCCH complexes have been investigated using the quantum chemical calculations on the HKrCCH-(H2O)n=1-6 clusters. Structure and energetics calculations show that water stabilizes HKrCCH through the π hydrogen bond in which the OH group of water interacts with the C[triple bond, length as m-dash]C group of HKrCCH. A maximum of four water molecules can directly interact with the C[triple bond, length as m-dash]C of HKrCCH and after that only inter-hydrogen bonding takes place between the water molecules indicating that the primary hydration shell contains four water molecules. Atom in molecule analysis depicts that π hydrogen bonded complexes of the hydrated HKrCCH are cyclic structures in which the OKr interaction cooperates in the formation of strong O-HC[triple bond, length as m-dash]C interaction. Structure, energetics and charge analysis clearly established that krypton plays an important role in the stabilization as well as the formation of the primary hydration shell of hydrated HKrCCH complexes.

Heme as a danger molecule in pathogen recognition.

Science.gov (United States)

Wegiel, Barbara; Hauser, Carl J; Otterbein, Leo E

2015-12-01

Appropriate control of redox mechanisms are critical for and effective innate immune response, which employs multiple cell types, receptors and molecules that recognize danger signals when they reach the host. Recognition of pathogen-associated pattern molecules (PAMPs) is a fundamental host survival mechanism for efficient elimination of invading pathogens and resolution of the infection and inflammation. In addition to PAMPs, eukaryotic cells contain a plethora of intracellular molecules that are normally secured within the confines of the plasma membrane, but if liberated and encountered in the extracellular milieu can provoke rapid cell activation. These are known as Alarmins or Danger-Associated Molecular Patterns (DAMPs) and can be released actively by cells or passively as a result of sterile cellular injury after trauma, ischemia, or toxin-induced cell rupture. Both PAMPs and DAMPs are recognized by a series of cognate receptors that increase the generation of free radicals and activate specific signaling pathways that result in regulation of a variety of stress response, redox sensitive genes. Multiple mediators released, as cells die include, but are not limited to ATP, hydrogen peroxide, heme, formyl peptides, DNA or mitochondria provide the second signal to amplify immune responses. In this review, we will focus on how sterile and infective stimuli activate the stress response gene heme oxygenase-1 (Hmox1, HO-1), a master gene critical to an appropriate host response that is now recognized as one with enormous therapeutic potential. HO-1 gene expression is regulated in large part by redox-sensitive proteins including but not limited to nrf2. Both PAMPs and DAMPs increase the activation of nrf2 and HO-1. Heme is a powerful pro-oxidant and as such should be qualified as a DAMP. With its degradation by HO-1a molecule of carbon monoxide (CO) is generated that in turn serves as a bioactive signaling molecule. PAMPs such as bacterial endotoxin activate HO-1

Like-charge attraction and opposite-charge decomplexation between polymers and DNA molecules

OpenAIRE

Buyukdagli, Sahin

2016-01-01

We scrutinize the effect of polyvalent ions on polymer-DNA interactions. We extend a recently developed test charge theory to the case of a stiff polymer interacting with a DNA molecule in an electrolyte mixture. The theory accounts for one-loop level electrostatic correlation effects such as the ionic cloud deformation around the strongly charged DNA molecule as well as image-charge forces induced by the low DNA permittivity. Our model can reproduce and explain various characteristics of the...

Adsorption of different amphiphilic molecules onto polystyrene latices.

Science.gov (United States)

Jódar-Reyes, A B; Ortega-Vinuesa, J L; Martín-Rodríguez, A

2005-02-15

In order to know the influence of the surface characteristics and the chain properties on the adsorption of amphiphilic molecules onto polystyrene latex, a set of experiments to study the adsorption of ionic surfactants, nonionic surfactants and an amphiphilic synthetic peptide on different latex dispersions was performed. The adsorbed amount versus the equilibrium surfactant concentration was determined. The main adsorption mechanism was the hydrophobic attraction between the nonpolar tail of the molecule and the hydrophobic regions of the latex surface. This attraction overcame the electrostatic repulsion between chains and latex surface with identical charge sign. However, the electrostatic interactions chain-surface and chain-chain also played a role. General patterns for the adsorption of ionic chains on charged latex surfaces could be established. Regarding the shape, the isotherms presented different plateaus corresponding to electrostatic effects and conformational changes. The surfactant size also affects the adsorption results: the higher the hydrophilic moiety in the surfactant molecule the lower the adsorbed amount.

Isotope separation using vibrationally excited molecules

International Nuclear Information System (INIS)

Woodroffe, J.A.; Keck, J.C.

1977-01-01

A system for isotope separation or enrichment wherein molecules of a selected isotope type in a flow of molecules of plural isotope types are vibrationally excited and collided with a background gas to provide enhanced diffusivity for the molecules of the selected isotope type permitting their separate collection. The system typically is for the enrichment of uranium using a uranium hexafluoride gas in combination with a noble gas such as argon. The uranium hexafluoride molecules having a specific isotope of uranium are vibrationally excited by laser radiation. The vibrational energy is converted to a translation energy upon collision with a particle of the background gas and the added translation energy enhances the diffusivity of the selected hexafluoride molecules facilitating its condensation on collection surfaces provided for that purpose. This process is periodically interrupted and the cryogenic flow halted to permit evaporation of the collected molecules to provide a distinct, enriched flow

Vibrationally coupled electron transport through single-molecule junctions

Energy Technology Data Exchange (ETDEWEB)

Haertle, Rainer

2012-04-26

Single-molecule junctions are among the smallest electric circuits. They consist of a molecule that is bound to a left and a right electrode. With such a molecular nanocontact, the flow of electrical currents through a single molecule can be studied and controlled. Experiments on single-molecule junctions show that a single molecule carries electrical currents that can even be in the microampere regime. Thereby, a number of transport phenomena have been observed, such as, for example, diode- or transistor-like behavior, negative differential resistance and conductance switching. An objective of this field, which is commonly referred to as molecular electronics, is to relate these transport phenomena to the properties of the molecule in the contact. To this end, theoretical model calculations are employed, which facilitate an understanding of the underlying transport processes and mechanisms. Thereby, one has to take into account that molecules are flexible structures, which respond to a change of their charge state by a profound reorganization of their geometrical structure or may even dissociate. It is thus important to understand the interrelation between the vibrational degrees of freedom of a singlemolecule junction and the electrical current flowing through the contact. In this thesis, we investigate vibrational effects in electron transport through singlemolecule junctions. For these studies, we calculate and analyze transport characteristics of both generic and first-principles based model systems of a molecular contact. To this end, we employ a master equation and a nonequilibrium Green's function approach. Both methods are suitable to describe this nonequilibrium transport problem and treat the interactions of the tunneling electrons on the molecular bridge non-perturbatively. This is particularly important with respect to the vibrational degrees of freedom, which may strongly interact with the tunneling electrons. We show in detail that the resulting

In vitro functional test of two subclasses of an anti-RhD antibody produced by transient expression in COS cells

DEFF Research Database (Denmark)

Nielsen, Leif Kofoed; Norderhaug, Lars; Sandlie, Inger

2006-01-01

For over 35 years hemolytic disease of the fetus and newborn (HDFN) due to RhD has been effectively prevented by anti-RhD antibodies obtained from alloimmunized women or deliberately immunized men. However, due to the reduced number of immunized women and for ethical reasons it is foreseen...

Effect of nontronite smectite clay on the chemical evolution of several organic molecules under simulated Mars surface UV radiation conditions

Science.gov (United States)

Poch, Olivier; Dequaire, Tristan; Stalport, Fabien; Jaber, Maguy; Lambert, Jean-François; Szopa, Cyril; Coll, Patrice

2015-04-01

The search for organic carbon-containing molecules at the surface of Mars, as clues of past habitability or remnants of life, is a major scientific goal for Mars exploration. Several lines of evidence, including the detection of phyllosilicates, suggest that early Mars offered favorable conditions for long-term sustaining of water. As a consequence, we can assume that in those days, endogenous chemical processes, or even primitive life, may have produced organic matter on Mars. Moreover, exogenous delivery from small bodies or dust particles is likely to have brought fresh organic molecules to the surface of Mars up today. Organic matter is therefore expected to be present at the surface/subsurface of the planet. But the current environmental conditions at the surface - UV radiation, oxidants and energetic particles - generate physico-chemical processes that may affect organic molecules. On the other hand, on Earth, phyllosilicates are known to accumulate and preserve organic matter. But are phyllosilicates efficient at preserving organic molecules under the current environmental conditions at the surface of Mars? We have monitored the qualitative and quantitative evolutions of glycine, urea and adenine interacting with the Fe3+-smectite clay nontronite, one of the most abundant phyllosilicates present at the surface of Mars, under simulated Martian surface ultraviolet light (190-400 nm), mean temperature (218 ± 2 K) and pressure (6 ± 1 mbar) in a laboratory simulation setup. We have tested organic-rich samples which may be representative of the evaporation of a warm little pond of liquid water having concentrated organics on Mars. For each molecule, we have observed how the nontronite influences the quantum efficiency of its photodecomposition and the nature of its solid evolution products. The results reveal a pronounced photoprotective effect of nontronite on the evolution of glycine and adenine: their efficiencies of photodecomposition are reduced by a factor