Sample records for scientifique au cea

  1. Detection of CEA in human serum using surface-enhanced Raman spectroscopy coupled with antibody-modified Au and γ-Fe₂O₃@Au nanoparticles.

    PubMed

    Lin, Yan; Xu, Guanhong; Wei, Fangdi; Zhang, Aixia; Yang, Jing; Hu, Qin

    2016-03-20

    In this present work, a rapid and simple method to detect carcinoembryonic antigen (CEA) was developed by using surface-enhanced Raman spectroscopy (SERS) coupled with antibody-modified Au and γ-Fe2O3@Au nanoparticles. First, Au@Raman reporter and γ-Fe2O3@Au were prepared, and then modified with CEA antibody. When CEA was present, the immuno-Au@Raman reporter and immuno-γ-Fe2O3@Au formed a complex through antibody-antigen-antibody interaction. The selective and sensitive detection of CEA could be achieved by SERS after magnetic separation. Under the optimal conditions, a linear relationship was observed between the Raman peak intensity and the concentration of CEA in the range of 1-50 ng mL(-1) with an excellent correlation coefficient of 0.9942. The limit of detection based on two times ratio of signal to noise was 0.1 ng/mL. The recoveries of CEA standard solution spiked with human serum samples were in the range of 88.5-105.9% with the relative standard deviations less than 17.4%. The method built was applied to the detection of CEA in human serum, and the relative deviations of the analysis results between the present method and electrochemiluminescence immunoassay were all less than 16.6%. The proposed method is practical and has a potential for clinic test of CEA. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Enhanced peroxidase-like properties of Au@Pt DNs/NG/Cu2+ and application of sandwich-type electrochemical immunosensor for highly sensitive detection of CEA.

    PubMed

    Lv, Hui; Li, Yueyun; Zhang, Xiaobo; Gao, Zengqiang; Zhang, Chunyan; Zhang, Shuan; Dong, Yunhui

    2018-07-30

    Effective treatment of cancer depends upon the early detection of the tumor marker. Here, we report on the development of a new immunosensor for early detection of carcinoembryonic antigen (CEA). Cubic Au@Pt dendritic nanomaterials functionalized nitrogen-doped graphene loaded with copper ion (Au@Pt DNs/NG/Cu 2+ ) with enhanced peroxidase-like properties was synthesized as labels to effectively capture and immobilize secondary anti-CEA. The Au@Pt DNs with more active surface area could efficiently enhance electrocatalysis for reduction of hydrogen peroxide (H 2 O 2 ). Meanwhile, with good conductivity and large specific surface area, NG can immobilize a large amount of Au@Pt DNs. Furthermore, after adsorbed Cu 2+ can further promote the redox of H 2 O 2 and amplify the signal of the immunosensor. For the immobilization of primary antibodies, Au nanoparticles functionalized polydopamine (Au@PDA) were used as transducing materials to modify glassy carbon electrodes and enhance the electron transfer efficiently. Under optimal conditions, the immunosensor exhibited a satisfactory response to CEA with a limit detection of 0.167 pg/mL and linear detection range from 0.5 pg/mL to 50 ng/mL. Based on the high sensitivity and specificity of the immunosensor, we propose this multiple amplified biosensor for early detection of CEA. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. AuNPs/CNOs/SWCNTs/chitosan-nanocomposite modified electrochemical sensor for the label-free detection of carcinoembryonic antigen.

    PubMed

    Rizwan, Mohammad; Elma, Syazwani; Lim, Syazana Abdullah; Ahmed, Minhaz Uddin

    2018-06-01

    In this work, a nanocomposite of gold nanoparticles (AuNPs), carbon nano-onions (CNOs), single-walled carbon nanotubes (SWCNTs) and chitosan (CS) (AuNPs/CNOs/SWCNTs/CS) was prepared for the development of highly sensitive electrochemical immunosensor for the detection of carcinoembryonic antigen (CEA), clinical tumor marker. Firstly, layer-by-layer fabrication of the CEA-immunosensors was studied using cyclic voltammetry (CV) and square wave voltammetry (SWV). By combining the advantages of large surface area and electronic properties of AuNPs, CNOs, SWCNTs, and film forming properties of CS, AuNPs/CNOs/SWCNTs/CS-nanocomposite-modified glassy carbon electrode showed a 200% increase in effective surface area and electronic conductivity. The calibration plot gave a negative linear relationship between log[concentration] of CEA and electrical current with a correlation coefficient of 0.9875. The CEA-immunosensor demonstrated a wide linear detection range of 100 fg mL -1 to 400 ng mL -1 with a low detection limit of 100 fg mL -1 . In addition to high sensitivity, reproducibility and large stability, CEA-immunosensor provided an excellent selectivity and resistant-to-interference in the presence of other antigens in serum and hence a potential to be used with real samples. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Le recours aux modeles dans l'enseignement de la biologie au secondaire : Conceptions d'enseignantes et d'enseignants et modes d'utilisation

    NASA Astrophysics Data System (ADS)

    Varlet, Madeleine

    Le recours aux modeles et a la modelisation est mentionne dans la documentation scientifique comme un moyen de favoriser la mise en oeuvre de pratiques d'enseignement-apprentissage constructivistes pour pallier les difficultes d'apprentissage en sciences. L'etude prealable du rapport des enseignantes et des enseignants aux modeles et a la modelisation est alors pertinente pour comprendre leurs pratiques d'enseignement et identifier des elements dont la prise en compte dans les formations initiale et disciplinaire peut contribuer au developpement d'un enseignement constructiviste des sciences. Plusieurs recherches ont porte sur ces conceptions sans faire de distinction selon les matieres enseignees, telles la physique, la chimie ou la biologie, alors que les modeles ne sont pas forcement utilises ou compris de la meme maniere dans ces differentes disciplines. Notre recherche s'est interessee aux conceptions d'enseignantes et d'enseignants de biologie au secondaire au sujet des modeles scientifiques, de quelques formes de representations de ces modeles ainsi que de leurs modes d'utilisation en classe. Les resultats, que nous avons obtenus au moyen d'une serie d'entrevues semi-dirigees, indiquent que globalement leurs conceptions au sujet des modeles sont compatibles avec celle scientifiquement admise, mais varient quant aux formes de representations des modeles. L'examen de ces conceptions temoigne d'une connaissance limitee des modeles et variable selon la matiere enseignee. Le niveau d'etudes, la formation prealable, l'experience en enseignement et un possible cloisonnement des matieres pourraient expliquer les differentes conceptions identifiees. En outre, des difficultes temporelles, conceptuelles et techniques peuvent freiner leurs tentatives de modelisation avec les eleves. Toutefois, nos resultats accreditent l'hypothese que les conceptions des enseignantes et des enseignants eux-memes au sujet des modeles, de leurs formes de representation et de leur approche

  5. Novel electrochemical redox-active species: one-step synthesis of polyaniline derivative-Au/Pd and its application for multiplexed immunoassay

    NASA Astrophysics Data System (ADS)

    Wang, Liyuan; Feng, Feng; Ma, Zhanfang

    2015-11-01

    Electrochemical redox-active species play crucial role in electrochemically multiplexed immunoassays. A one-pot method for synthesizing four kinds of new electrochemical redox-active species was reported using HAuCl4 and Na2PdCl4 as dual oxidating agents and aniline derivatives as monomers. The synthesized polyaniline derivative-Au/Pd composites, namely poly(N-methyl-o-benzenediamine)-Au/Pd, poly(N-phenyl-o-phenylenediamine)-Au/Pd, poly(N-phenyl-p-phenylenediamine)-Au/Pd and poly(3,3’,5,5’-tetramethylbenzidine)-Au/Pd, exhibited electrochemical redox activity at -0.65 V, -0.3 V, 0.12 V, and 0.5 V, respectively. Meanwhile, these composites showed high H2O2 electrocatalytic activity because of the presence of Au/Pd. The as-prepared composites were used as electrochemical immunoprobes in simultaneous detection of four tumor biomarkers (carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA199), carbohydrate antigen 72-4 (CA724), and alpha fetoprotein (AFP)). This immunoassay shed light on potential applications in simultaneous gastric cancer (related biomarkers: CEA, CA199, CA724) and liver cancer diagnosis (related biomarkers: CEA, CA199, AFP). The present strategy to the synthesize redox species could be easily extended to other polymers such as polypyrrole derivatives and polythiophene derivatives. This would be of great significance in the electrochemical detection of more analytes.

  6. L'astronomie au féminin

    NASA Astrophysics Data System (ADS)

    Nazé, Yaël

    2006-03-01

    Qui détient le record des découvertes de comètes ? Une femme. Qui a permis de comprendre comment est organisée la population des étoiles ? Une femme. Qui a découvert la loi permettant d'arpenter l'Univers, a trouvé des phares dans l'espace, a compris le fonctionnement des forges stellaires et a bouleversé notre vision de l'Univers ? Encore et toujours une femme... Pourtant, quand on doit citer un astronome -- historique -- au hasard, on pense le plus souvent -- des hommes : Ptolémée, Galilée, Copernic ou, plus près de nous par exemple, Hubble. Certes, au cours des siècles, les femmes n'ont guère eu accès aux sciences en général et -- l'astronomie en particulier mais ce n'est pas une raison pour croire en l'absence totale de contributions dues au beau sexe ! C'est ce que dévoile ici l'auteur. Loin de toute forme de féminisme enragé, on suivra le parcours de quelques scientifiques importantes qui ont par hasard en commun une même particularité : leur sexe.

  7. Relationship of serum CEA levels to tumour size and CEA content in nude mice bearing colonic-tumour xenografts.

    PubMed Central

    Lewis, J. C.; Keep, P. A.

    1981-01-01

    The relationship of serum carcinoembryonic antigen (CEA) levels to tumour size and antigen content was studied in nude mice bearing well differentiated, mucinous human colonic-tumour xenografts. Blood samples were taken from normal nude mice and others bearing xenografts, whose size had been calculated from in vivo measurements; saline and KCl extracts were made of a proportion of these tumours. Sera and tissue extracts were assayed for CEA activity by double-antibody radioimmunoassay. Extracts were also made from the livers and spleens of tumour-bearing and normal nude mice. All normal sera and 78% of sera from tumour-bearing animals had CEA values less than 11.4 ng/ml. No clear correlation was found between serum CEA levels greater than 11.4 ng/ml and tumour size or weight, or between serum CEA and tumour CEA concentrations or total CEA burden. The concentration of CEA in those tumours tested varied from 1 to 22 microgram/g. Our results confirm and extend the conclusions reached by others (Stragand et al., 1980) studying the significance of serum CEA levels with xenograft model systems. The complexity of factors contributing to circulating CEA is discussed in the light of our findings. Images Fig. 1 PMID:7284235

  8. [Significance of CEA in gastric and colorectal cancer].

    PubMed

    Uehara, K; Miyamoto, Y; Izuo, M; Shiozaki, H; Aiba, S; Matsumoto, H

    1985-04-01

    The determination of serum CEA (Sandwich method) and CEA staining (PAP method) of excised specimens were performed in patients with gastric or colorectal cancer, and the biological characteristics of each cancer and the factors to increase serum CEA were studied with the following results: As colonic cancer has strong CEA productivity, serum CEA can be useful for the detection of cancer, and especially effective for the postoperative observation. Gastric cancer has weak CEA productivity, and serum CEA is not so useful in the detection of cancer and the judgement of resectability. The CEA positive rate of tissue with CEA staining was 80% in gastric cancer, 100% in colonic cancer, and were nearly equal to the CEA positive rate of serum in the group of terminal stage. In the mode of CEA staining of cancerous cells, IV type was observed most frequently in gastric cancer, and I type in colonic cancer. Among the resected cases showing more than 7ng/ml serum CEA, differentiated type, lymph node metastasis (+), the degree of tissue staining with CEA staining, the mode of cell staining O or I type in gastric cancer and I type in colonic cancer were observed in common.

  9. A monoclonal antibody against neem leaf glycoprotein recognizes carcinoembryonic antigen (CEA) and restricts CEA expressing tumor growth.

    PubMed

    Das, Arnab; Barik, Subhasis; Banerjee, Saptak; Bose, Anamika; Sarkar, Koustav; Biswas, Jaydip; Baral, Rathindranath; Pal, Smarajit

    2014-10-01

    Carcinoembryonic antigen (CEA) is one of the promising tumor antigens mainly associated with carcinoma of the colon, lung, breast, etc. and received wide attention for cancer immunotherapy. Neem leaf glycoprotein (NLGP), an effective immunomodulator, is able to generate humoral and cellular immune responses in murine tumor models. We have generated a monoclonal antibody (mAb) against NLGP by fusing NLGP-immunized mice splenocytes with nonsecretory myeloma cells. A highly anti-NLGP mAb secreting clone (1C8; IgG2a in nature) has been identified and propagated in culture. 1C8 recognizes human CEA as good as NLGP by enzyme linked immunosorbent assay, Western blotting, and immunoprecipitation. 1C8 detects CEA on colon cancer tissues by immunochistochemistry. By flow cytometry, 1C8 specifically reacts with CEA(+) human (Colo-205, HCT-116, and HT-29) and mouse (CT-26) colon cancer cells, but it showed minimum reactivity with CEA(-) human (MCF7, SiHa, and SCC084) and mouse (B16MelF10) cancer cells. This anti-NLGP 1C8 mAb revealed significant antitumor activity and better survivability in vivo in animals bearing mouse (CT-26 in BALB/c) and human (Colo-205 in athymic nude) CEA(+) cancer cells. 1C8 has no direct influence on proliferation and migration of CEA(+) cells, however, NK cell-dependent strong antibody-dependent cellular cytotoxicity reaction toward CEA(+) cells and normalization of angiogenesis are chiefly associated with tumor growth restriction. Obtained results provided a new immunotherapeutic approach for the effective management of CEA(+) tumors.

  10. Mouse models expressing human carcinoembryonic antigen (CEA) as a transgene: Evaluation of CEA-based cancer vaccines

    PubMed Central

    Hance, Kenneth W.; Zeytin, Hasan E.; Greiner, John W.

    2010-01-01

    In recent years, investigators have carried out several studies designed to evaluate whether human tumor-associated antigens might be exploited as targets for active specific immunotherapy, specifically human cancer vaccines. Not too long ago such an approach would have been met with considerable skepticism because the immune system was believed to be a rigid discriminator between self and non-self which, in turn, protected the host from a variety of pathogens. That viewpoint has been challenged in recent years by a series of studies indicating that antigenic determinants of self have not induced absolute host immune tolerance. Moreover, under specific conditions that evoke danger signals, peptides from self-antigen can be processed by the antigen-presenting cellular machinery, loaded onto the major histocompatibility antigen groove to serve as targets for immune intervention. Those findings provide the rationale to investigate a wide range of tumor-associated antigens, including differentiation antigens, oncogenes, and tumor suppressor genes as possible immune-based targets. One of those tumor-associated antigens is the carcinoembryonic antigen (CEA). Described almost 40 years ago, CEA is a Mr 180–200,000 oncofetal antigen that is one of the more widely studied human tumor-associated antigens. This review will provide: (i) a brief overview of the CEA gene family, (ii) a summary of early preclinical findings on overcoming immune tolerance to CEA, and (iii) the rationale to develop mouse models which spontaneously develop gastrointestinal tumors and express the CEA transgene. Those models have been used extensively in the study of overcoming host immune tolerance to CEA, a self, tumor-associated antigen, and the experimental findings have served as the rationale for the design of early clinical trials to evaluate CEA-based cancer vaccines. PMID:15888344

  11. CEA monitoring of palliative treatment for colorectal carcinoma.

    PubMed Central

    Herrera, M A; Chu, T M; Holyoke, E D; Mittelman, A

    1977-01-01

    Palliative treatment was applied to 131 cases of unresectable or palliatively resected colorectal carcinoma being monitored with serial CEA determinations. There were 84 instances of disease progression with 67 (80%) of them showing an increase in CEA above pretreatment levels or maintaining high levels, and 17 (20%) showing a fall when compared to pretreatment values or maintaining low initial values. There was a clear-cut regression of the disease in only 9 instances. In all 9, the CEA clearly dropped or maintained low valles throughout the period of regression. No patient in regression had a rise or maintained an elevated CEA level. These changes in CEA followed closely the clinical response of our patient to the use of a particular agent, although for the Nitrosourea compounds there may be a tendency to lower the CEA regardless of the patient's tumor response to the drug. This could be due to the fact that the Nitrosoureas produce a diffuse block of cellular activity, both at the nucleous and cytoplasm; while other compounds act as alkylating agents or by inhibition of enzymes involved in the metabolism of nucleic acids (i.e., 5-FU inhibiting thymidylate synthetase). In general, longer survival was found in those patients who had initially lower levels of CEA as compared to those with high initial levels. The patients with a favorable CEA response to the treatment (falling CEA or maintained low value), even in many who did not show a clinical response had a longer survival than the group with rising or stable high levels. The main value in CEA monitoring of patients resides in its correlation with the amount of disease present and then its ability to detect progression of tumor mass which is not clinically measurable. PMID:64132

  12. cea-kil operon of the ColE1 plasmid.

    PubMed Central

    Sabik, J F; Suit, J L; Luria, S E

    1983-01-01

    We isolated a series of Tn5 transposon insertion mutants and chemically induced mutants with mutations in the region of the ColE1 plasmid that includes the cea (colicin) and imm (immunity) genes. Bacterial cells harboring each of the mutant plasmids were tested for their response to the colicin-inducing agent mitomycin C. All insertion mutations within the cea gene failed to bring about cell killing after mitomycin C treatment. A cea- amber mutation exerted a polar effect on killing by mitomycin C. Two insertions beyond the cea gene but within or near the imm gene also prevented the lethal response to mitomycin C. These findings suggest the presence in the ColE1 plasmid of an operon containing the cea and kil genes whose product is needed for mitomycin C-induced lethality. Bacteria carrying ColE1 plasmids with Tn5 inserted within the cea gene produced serologically cross-reacting fragments of the colicin E1 molecule, the lengths of which were proportional to the distance between the insertion and the promoter end of the cea gene. Images PMID:6298187

  13. Design and Impacts of a Youth-Directed Café Scientifique Program

    ERIC Educational Resources Information Center

    Hall, Michelle K.; Foutz, Susan; Mayhew, Michael A.

    2013-01-01

    We have modified the popular Cafe Scientifique model for engaging adults in dialog on issues at the nexus of science and society to address the specific needs and interests of high-school age youth. Key elements of the model are Youth Leadership Teams that guide the program design and assist with implementation; a speaker preparation process to…

  14. Evaluation d'un scenario d'apprentissage favorisant la mobilisation des habiletes reliees au processus d'enquete

    NASA Astrophysics Data System (ADS)

    Blanchard, Samuel F. J.

    Les resultats au Programme international pour le suivi des acquis des eleves (PISA) demontrent que les jeunes neobrunswickois francophones se classent b un niveau significativement inferieur comparaiivement aux eleves anglophones du Nouveau-Brunswick, aux eleves des autres provinces canadiennes et se classent sous la moyenne internationale de tous les pays participants quant b la culture scientifique. L'evaluation de cette culture scientifique est basee sur une serie de savoirs, de savoir-faire et de savoir-etre reliee au processus d'enquete scolaire. Le processus d'enquete scolaire est une approche b l'apprentissage ou les eleves effectuent des recherches d'informations, discutent d'idees et entreprennent des investigations pour augmenter leur comprehension d'un probleme ou d'un sujet. Les recherches demontrent que le processus d'enquete scolaire est rarement une composante pedagogique importante de la salle de classe et les recherches portant sur l'implantation du processus d'enquete scolaire recommandent de rendre ce dernier plus accessible aux enseignantes et aux enseignants. Afin de rendre le processus d'enquete plus accessible aux enseignantes et aux enseignants, notre recherche porte sur l'evaluation de la valeur pedagogique d'un scenario d'apprentissage (PhaRoboS) concu specialement pour creer un environnement dans lequel les eleves auront plusieurs occasions a mobiliser les habiletes reliees au processus d'enquete. Les retombees de cette evaluation nous permettront d'offrir des pistes de remediations afin d'aider plus d'enseignantes et d'enseignants b creer un environnement dans lequel les eleves auront plusieurs occasions b mobiliser les habiletes reliees au processus d'enquete. Cette evaluation s'est faite a partir d'une methodologie inspiree de l'evaluation pour fin d'amelioration d'un objet pedagogique. L'analyse des donnees qualitatives recueillies aupres des eleves et de leur enseignante d'une ecole francophone du Nouveau-Brunswick semble montrer que

  15. The CEA-/lo colorectal cancer cell population harbors cancer stem cells and metastatic cells.

    PubMed

    Yan, Chang; Hu, Yibing; Zhang, Bo; Mu, Lei; Huang, Kaiyu; Zhao, Hui; Ma, Chensen; Li, Xiaolan; Tao, Deding; Gong, Jianping; Qin, Jichao

    2016-12-06

    Serum carcinoembryonic antigen (CEA) is the most commonly used tumor marker in a variety of cancers including colorectal cancer (CRC) for tumor diagnosis and monitoring. Recent studies have shown that colonic crypt cells expressing little or no CEA may enrich for stem cells. Numerous studies have clearly shown that there exist CRC patients with normal serum CEA levels during tumor progression or even tumor relapse, although CEA itself is considered to promote metastasis and block cell differentiation. These seemingly contradictory observations prompted us to investigate, herein, the biological properties as well as tumorigenic and metastatic capacity of CRC cells that express high (CEA+) versus low CEA (CEA-/lo) levels of CEA. Our findings show that the abundance of CEA-/lo cells correlate with poor differentiation and poor prognosis, and moreover, CEA-/lo cells form more spheres in vitro, generate more tumors and exhibit a higher potential in developing liver and lung metastases than corresponding CEA+ cells. Applying RNAi-mediated approach, we found that IGF1R mediated tumorigenic and capacity of CEA-/lo cells but did not mediate those of CEA+ cells. Notably, our data demonstrated that CEA molecule was capable of protecting CEA-/lo cells from anoikis, implying that CEA+ cells, although themselves possessing less tumorigenic and metastatic capacity, may promote metastasis of CEA-/lo cells via secreting CEA molecule. Our observations suggest that, besides targeting CEA molecule, CEA-/lo cells may represent a critical source of tumor progression and metastasis, and should therefore be the target of future therapies.

  16. Polyaniline modified flexible conducting paper for cancer detection

    NASA Astrophysics Data System (ADS)

    Kumar, Saurabh; Sen, Anindita; Kumar, Suveen; Augustine, Shine; Yadav, Birendra K.; Mishra, Sandeep; Malhotra, Bansi D.

    2016-05-01

    We report results of studies relating to the fabrication of a flexible, disposable, and label free biosensing platform for detection of the cancer biomarker (carcinoembryonic antigen, CEA). Polyaniline (PANI) has been electrochemically deposited over gold sputtered paper (Au@paper) for covalent immobilization of monoclonal carcinoembryonic antibodies (anti-CEA). The bovine serum albumin (BSA) has been used for blocking nonspecific binding sites at the anti-CEA conjugated PANI/Au@Paper. The PANI/Au@Paper, anti-CEA/PANI/Au@Paper, and BSA/anti-CEA/PANI/Au@Paper platforms have been characterized using scanning electron microscopy, X-ray diffraction, Fourier transmission infrared spectroscopy, chronoamperometry, and electrochemical impedance techniques. The results of the electrochemical response studies indicate that this BSA/anti-CEA/PANI/Au@paper electrode has sensitivity of 13.9 μA ng-1 ml cm2, shelf life of 22 days, and can be used to estimate CEA in the range of 2-20 ng ml-1. This paper sensor has been validated by detection of CEA in serum samples of cancer patients via immunoassay technique.

  17. In vitro and in vivo comparison of binding of 99m-Tc-labeled anti-CEA MAb F33-104 with 99m-Tc-labeled anti-CEA MAb BW431/26.

    PubMed

    Watanabe, N; Oriuchi, N; Sugiyama, S; Kuroki, M; Matsuoka, Y; Tanada, S; Murata, H; Inoue, T; Sasaki, Y

    1999-01-01

    The purpose of this study was to assess the potential for radio-immunodetection (RAID) of murine anti-carcinoembryonic antigen (CEA) monoclonal antibody (MAb) F33-104 labeled with technetium-99m (99m-Tc) by a reduction-mediated labeling method. The binding capacity of 99m-Tc-labeled anti-CEA MAb F33-104 with CEA by means of in vitro procedures such as immunoradiometric assay and cell binding assay and the biodistribution of 99m-Tc-labeled anti-CEA MAb F33-104 in normal nude mice and nude mice bearing human colon adenocarcinoma LS180 tumor were investigated and compared with 99m-Tc-labeled anti-CEA MAb BW431/26. The in vitro binding rate of 99m-Tc-labeled anti-CEA MAb F33-104 with CEA in solution and attached to the cell membrane was significantly higher than 99m-Tc-labeled anti-CEA MAb BW431/261 (31.4 +/- 0.95% vs. 11.9 +/- 0.55% at 100 ng/mL of soluble CEA, 83.5 +/- 2.84% vs. 54.0 +/- 2.54% at 10(7) of LS 180 cells). In vivo, accumulation of 99m-Tc-labeled anti-CEA MAb F33-104 was higher at 18 h postinjection than 99m-Tc-labeled anti-CEA MAb BW431/26 (20.1 +/- 3.50% ID/g vs. 14.4 +/- 3.30% ID/g). 99m-Tc-activity in the kidneys of nude mice bearing tumor was higher at 18 h postinjection than at 3 h (12.8 +/- 2.10% ID/g vs. 8.01 +/- 2.40% ID/g of 99m-Tc-labeled anti-CEA MAb F33-104, 10.7 +/- 1.70% ID/g vs. 8.10 +/- 1.75% ID/g of 99m-Tc-labeled anti-CEA MAb BW431/26). 99m-Tc-labeled anti-CEA MAb F33-104 is a potential novel agent for RAID of recurrent colorectal cancer.

  18. Introduction to the CEA family: structure, function and secretion.

    PubMed

    Von Kleist, S

    1992-01-01

    Due to the phenomenal progress in the field of tumor immunology that took place during the last twenty years, we dispose today of highly specific and sensitive techniques and reagents like monoclonal antibodies (MAbs). In this context the discovery in human carcinomas of tumor-associated antigens, such as CEA, was of primary importance, especially since the latter was found to have clinical relevance as a tumor marker. Based on animal models, a new in vivo technology for the detection of tumors and metastases was developed in recent years, that uses anti-CEA MAbs, or fragments of them, coupled to radio-isotopes. This technique, called radio-immunodetection (RAID), also paved the way for immunotherapeutic procedures, where again CEA served as the target-antigen. This new technique holds great promise, provided the epitope-specificity of the MAbs is well-controlled: it has been shown that CEA belongs to a large gene-family of at least 22 members, which can be subdivided into two subgroups (i.e., the CEA- and the PSG-subgroup) and which in turn belongs to the immunoglobulin-supergene family. Great structural similarities render the distinction of the various cross-reactive molecules by immunological means rather difficult.

  19. Carcinoembryonic antigen (CEA) levels in hookah smokers, cigarette smokers and non-smokers.

    PubMed

    Sajid, Khan Mohammad; Parveen, Riffat; Durr-e-Sabih; Chaouachi, Kamal; Naeem, Ayisha; Mahmood, Rubaida; Shamim, Rahat

    2007-12-01

    To find CEA levels in smokers of different categories (hookah smokers, cigarette smokers smoking different brands of cigarettes and different number of cigarettes per day) and to correlate CEA levels with type and rate of smoking. A total of 122 cigarette smokers (115 men and 7 women) and 14 hookah smokers (all men) with age ranging from 16-80 years were studied. CEA levels were also measured in 36 non-smokers who served as controls. Enhanced chemilumiscent immunometeric technique was applied to measure CEA levels in our subjects. The mean CEA levels of cigarette smokers were compared with the mean CEA levels observed in hookah smokers (7.16 +/- 10.4 ng/ml) and non-smokers (2.15 +/- 0.68 ng/ml). The mean value of CEA level observed in cigarette smokers, 9.19 +/- 14.9 ng/ml (n=122) was significantly higher than the levels in non-smokers and hookah smokers (p < 0.0067). It was also observed that CEA levels increased with the number of cigarettes smoked per day. The highest levels were observed in smokers who smoke more than 31 cigarettes per day. The smokers that use relatively cheaper brands of cigarettes had higher levels of CEA compared to those who use high quality brands. It was concluded that the brands of cigarettes (which were ranked on the basis of price) and the rate of smoking both play an important role in raising the CEA levels. Further the common belief that hookah also called narghile or shisha is a relatively safe mode of smoking is not completely correct; a significant proportion of hookah smokers have high levels of CEA although mean levels of hookah smokers were low compared to cigarette smokers.

  20. Polyaniline modified flexible conducting paper for cancer detection

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kumar, Saurabh; Sen, Anindita; Kumar, Suveen

    We report results of studies relating to the fabrication of a flexible, disposable, and label free biosensing platform for detection of the cancer biomarker (carcinoembryonic antigen, CEA). Polyaniline (PANI) has been electrochemically deposited over gold sputtered paper (Au@paper) for covalent immobilization of monoclonal carcinoembryonic antibodies (anti-CEA). The bovine serum albumin (BSA) has been used for blocking nonspecific binding sites at the anti-CEA conjugated PANI/Au@Paper. The PANI/Au@Paper, anti-CEA/PANI/Au@Paper, and BSA/anti-CEA/PANI/Au@Paper platforms have been characterized using scanning electron microscopy, X-ray diffraction, Fourier transmission infrared spectroscopy, chronoamperometry, and electrochemical impedance techniques. The results of the electrochemical response studies indicate that this BSA/anti-CEA/PANI/Au@paper electrodemore » has sensitivity of 13.9 μA ng{sup −1} ml cm{sup 2}, shelf life of 22 days, and can be used to estimate CEA in the range of 2–20 ng ml{sup −1}. This paper sensor has been validated by detection of CEA in serum samples of cancer patients via immunoassay technique.« less

  1. Levels of CEA among vinyl chloride and polyvinyl chloride exposed workers

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Anderson, H.A.; Snyder, J.; Lewinson, T.

    1978-09-01

    In 1974, vinyl chloride exposed workers were found to have an increased risk of malignant disease (hemangiosarcoma of the liver). We have examined 1,147 workers exposed to vinyl chloride monomer in three VC/PVC polymerization plants, and 269 workers from a PVC extrusion plant manufacturing PVC textile leather, exposed to much lower concentrations of vinyl chloride. Included among the comprehensive clinical and laboratory studies conducted was the CEA titer. We obtained, respectively, 1,115 and 248 CEA titers. Multiple factors were demonstrated which affected the distribution of CEA titers. Cigarette use had the greatest effect, followed by history of specific past illnessesmore » and alcohol intake history. After removing these possible confounding effects, the distribution of CEA titers among the polymerization workers was significantly different from the extrusion plant group and from an unexposed comparison group. Of the six job categories analyzed, only production and maintenance workers had CEA titer distributions significantly different from the comparison group and the extrusion workers. The investigation demonstrates that occupational exposures in VC/PVC polymerization plants can cause elevations in the CEA titers of otherwise healthy individuals. Prospective follow-up is necessary before conclusions can be drawn concerning the usefulness of the CEA titer as a predictive indicator of possible increased risk.« less

  2. [Antigens (CEA and CA 19-9) in diagnosis and prognosis colorectal cancer].

    PubMed

    Grotowski, Maciej

    2002-01-01

    carcinoembryonic antigen (CEA) was first described more than three decades ago, when its presence was demonstrated in fetal gut tissue and in tumors from gastrointestinal tract. Subsequently, CEA was detected in the circulation of patients and recognized as a serum marker for colorectal cancer. This tumor marker has not been advocated as a screening test for colorectal cancer, however a preoperative CEA serum level is useful for diagnosis and prognosis of recurrence and survival in colorectal cancer patients. The levels of CEA increased with increasing tumor stage. Expression of carbohydrate antigen (CA 19-9) has been described in various malignancies and also in colorectal cancer. This antigen also has not been advocated as a screening test for colorectal cancer. The levels of CA 19-9 increased in advanced stages of colorectal cancer. Despite its lower sensitivity than CEA in early stages of colorectal cancer, the combination of both antigens can provided more information than CEA alone for prognosis of recurrence and survival in those patients.

  3. [Usefulness of preoperative assay CEA and CA 19-9 in colorectal cancer patients].

    PubMed

    Grotowski, M; Maruszyński, M; Piechota, W

    2001-12-01

    Carcinoembryonic antigen (CEA) and carbohydrate antigen (CA19-9) are well known tumor markers expressed by colorectal cancer (CRC), particularly in advanced cases. In this study serological expression of CEA and CA19-9 concerning different clinicopathological factors and sensitivity of diagnosis of CRC by combination of both markers were evaluated. Eighty one patients with diagnosed CRC were in this study included. According to Dukes' classification there were 11 in stage A, 34 in stage B, 17 in stage C and 19 in stage D. Blood samples were collected before operation. CEA and CA19-9 were determined by MEIA (normal range 0-3 ng/ml for CEA and 0-37 U/ml for CA19-9). The statistical analysis revealed that the CEA well correlated with histological type, liver metastasis and term of symptoms. The CA19-9 well correlated with liver metastasis, peritoneal dissemination, nodal involvement and cancer localization. The levels of CEA and CA19-9 increased with stage of the tumor, but only in stage D the difference was statistically significant (for CEA p = 0.005, for CA19-9 p = 0.039). At time of diagnosis 50.6% of the patients had elevated serum levels of CEA and 29.6% of CA19-9. In combination of both antigens this elevation was in 54.3% of CRC patients. The common use of CEA and CA19-9 was more efficacious in identification of patients at high risk. The combination assay of CEA and CA19-9 did not cause a significant increase of sensitivity in diagnosis CRC.

  4. Cancer imaging with CEA antibodies: historical and current perspectives.

    PubMed

    Goldenberg, D M

    1992-01-01

    This article reviews the history and status of cancer imaging with radiolabeled antibodies against carcinoembryonic antigen (CEA). Although CEA and many other cancer-associated antigens are not distinct for neoplasia, the quantitative increase of these markers in malignant tissues provides a sufficient differential for selective antibody targeting. Animal studies with xenografted human tumors provided the first evidence of the prospects of this technology, followed by initial clinical success with purified goat whole IgG antibodies to CEA, labeled with 131I and with the use of dual-isotope subtraction methods. Subsequently, improved and earlier imaging could be accomplished with monoclonal antibody fragments, which then would permit the use of shorter-lived radionuclides, such as 111In, 123I, and 99mTc. The preferred use of a monoclonal anti-CEA IgG Fab' fragment, labeled with 99mTc by a recently developed, simple and rapid kit, has enabled the detection of small lesions, including those in the liver, within 4 h of injection. By means of SPECT imaging, a high sensitivity and specificity for RAID could be achieved.

  5. Surface expression and CEA binding of hnRNP M4 protein in HT29 colon cancer cells.

    PubMed

    Laguinge, Luciana; Bajenova, Olga; Bowden, Emma; Sayyah, Jacqueline; Thomas, Peter; Juhl, Hartmut

    2005-01-01

    Carcinoembryonic antigen (CEA) has been shown to participate in the progression and metastatic growth of colorectal cancer. However, its biological function remains elusive. Recently, we found that CEA protects colon cancer cells from undergoing apoptosis, suggesting a complex role that includes signal transduction activity. Additionally, it was reported that CEA binds to Kupffer cells and macrophages to a membrane-anchored homolog of heterogeneous nuclear protein M4 (hnRNP M4), which subsequently was named CEA-receptor (CEAR). Cytoplasmatic and membranous expression of CEAR in CEA-positive colon cancer tissues prompted us to analyze the CEA-CEAR interaction in HT29 colon cancer cells. Both, CEA and CEAR were found on the cell surface of HT29 cells, as demonstrated by confocal microscopy. Imaging analysis suggested co-localization and, thus, interaction of both molecules. To confirm this observation, immunoprecipitation experiments and Western blot analysis were performed and indicated binding of CEA and CEAR. Immunoprecipitation of CEA resulted in a pull down of CEAR. The pull down of CEAR correlated with the amount of CEA as demonstrated by ribozyme targeting of CEA. Finally, external treatment of HT29 cells with soluble CEA induced tyrosine phosphorylation of CEAR, suggesting a CEA-dependent role of CEAR in signal transduction. Future experiments will elucidate whether the CEA-CEAR interaction is involved in CEA's antiapoptotic role and mediates the prometastatic properties of CEA in colon cancer cells.

  6. Ultra-relativistic Au+Au and d+Au collisions:

    NASA Astrophysics Data System (ADS)

    Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Chai, Z.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Hauer, M.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Seals, H.; Sedykh, I.; Skulski, W.; Smith, C. E.; Stankiewicz, M. A.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tang, J.-L.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Wenger, E.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    In this talk I will review PHOBOS data on charged particle multiplicities, obtained in Au+Au and d+Au collisions at RHIC. The general features of the Au+Au pseudorapidity distributions results will be discussed and compared to those of /line{p}p collisions. The total charged particle multiplicity, scaled by the number of participant pairs, is observed to be about 40% higher in Au+Au collisions than in /line{p}p and d+Au systems, but, surprisingly at the same level of e+e- collisions. Limiting fragmentation scaling is seen to be obeyed in Au+Au collisions.

  7. Le changement comme tradition dans la recherche et la formation a la recherche en biotechnologie et en peripherie Etude de cas en sciences de la sante, sciences naturelles et genie

    NASA Astrophysics Data System (ADS)

    Bourque, Claude Julie

    Le champ de la recherche scientifique et de la formation a la recherche est traverse depuis quelques dizaines d'annees par plusieurs courants et discours associes au changement, mais peu de travaux empiriques permettent de comprendre ce qui change concretement. C'est la contribution originale de cette these au champ de l'education, plus specifiquement a l'etude sociologique de l'enseignement superieur ou sont concentrees les activites liees a la triade thematique du programme doctoral dans lequel elle a ete produite : recherche, formation et pratique. L'enquete-terrain a ete realisee en 2009 et 2010 aupres de 808 repondants affilies a 60 etablissements au Quebec et a produit un vaste materiau de nature mixte (donnees quantitatives et qualitatives). Un portrait de la nebuleuse biotechnologique qui touche les secteurs des sciences de la sante, des sciences naturelles et du genie a ete realise. Ce domaine concerne des dizaines de disciplines et se revele de nature transdisciplinaire, mais les pratiques n'y sont pas davantage marquees par le changement que celles d'autres domaines connexes. Les dynamiques sociales ont fait l'objet d'analyses comparatives dans quatre contextes: le choix des programmes, des objets et des methodes, le financement, la diffusion et la planification de la carriere. Les resultats indiquent que les echanges entre les agents traditionnellement situes au coeur des activites de recherche dominent ces dynamiques dans tous les contextes etudies. L'etude des representations au fondement des pratiques a revele l'existence de trois ecoles de pensee qui coexistent dans le champ scientifique: academique, pragmatique et economiste. Ces ecoles permettent de categoriser les agents en fonction des zones de fractures qui marquent leurs oppositions tout en identifiant ce qu'ils ont en commun. Les representations et les pratiques liees a la formation temoignent d'un habitus plutot homogene, alors que les contradictions semblent plus souvent ancrees dans des

  8. A sensitive label-free amperometric CEA immunosensor based on graphene-nafion nanocomposite film as an enhanced sensing platform.

    PubMed

    Li, Yan; Yang, Wei-Kang; Fan, Man-Qi; Liu, Ao

    2011-01-01

    A novel approach to fabricate a label-free amperometric immunosensor for the detection of carcinoembryonic antigen (CEA) was described. Herein, methylene blue (MB), gold nanoparticles (AuNPs) and carcinoembryonic antibody (anti-CEA) were layer-by-layer assembled on the graphene-Nafion nanocomposite film-modified electrode by means of a self-assembling technique and the opposite-charged adsorption. Subsequently, the stepwise self-assembling procedure of the immunosensor was further characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The factors influencing the performance of the resulting immunosensor were studied in detail. The developed procedure showed improved features, including larger amount and higher immunoactivity of the immobilized antibody and repeatable regeneration of the sensor, as well as direct, rapid and simple determination for the antigen without multiple separation and labeling steps. The immunosensor could detect the target protein in a range of 0.5 to 120 ng/mL with a limit of 0.17 ng/mL (at 3σ). Finally, the immunosensing system was evaluated on several clinical samples. Analytical results were found to be in satisfactory agreement with those detected by the enzyme-linked immunosorbent assay (ELISA) method, indicating that this new method was a promising alternative tool for clinical diagnosis.

  9. Demonstration of monoclonal anti-carcinoembryonic antigen (CEA) antibody internalization by electron microscopy, western blotting and radioimmunoassay.

    PubMed

    Tsaltas, G; Ford, C H; Gallant, M

    1992-01-01

    One of the important factors affecting the action of monoclonal antibodies (Mabs) or immunoconjugates on tumour sites depends on whether the Mab is internalized by the cancer cells in question. The underexplored subject of internalization is discussed in this paper, and a number of in vitro techniques for investigating internalization are evaluated, using a model which consists of a well characterized anti-carcinoembryonic antigen (anti-CEA) Mab and a number of CEA expressing human cancer cell lines. Employing two alternative radiolabeling assays, evidence for internalization of the anti-CEA Mab by a CEA-positive colorectal cancer cell line (LS174T) was obtained throughout the time intervals examined (5 min to 150 min). Electronmicroscopy employing horseradish-peroxidase labeled anti-CEA Mab and control antibody permitted direct visualization of anti-CEA Mab-related staining in intracellular compartments of a high CEA-expressor human colorectal cell line (SKCO1). Finally Western blots of samples derived from cytosolic and membrane components of solubilized cells from lung and colonic cancer cell lines provided evidence for internalized anti-CEA Mab throughout seven half hour intervals, starting at 5 minutes. Internalized anti-CEA was detected in all CEA expressing cell lines (LS174T, SKCO1, BENN) but not in the case of a very low CEA expressor line (COLO 320).

  10. Préface

    NASA Astrophysics Data System (ADS)

    Mazière, D.

    2002-04-01

    Faisant suite aux deux précédents colloques "Matériaux pour les machines thermiques" et "Matériaux pour le nucléaire" , le colloque 2001 de l'INSTN intitulé "Matériaux pour les énergies propres" s'est focalisé sur les problèmes de matériaux encore à résoudre dans ce secteur industriel. Le colloque de métallurgie est traditionnellement organisé par des ense ignants du DEA Métallurgie et Matériaux et un comité scientifique choisi chaq ue année en liaison avec le thème traité. Les étudiants de ce DEA, qui est hab ilité entre Paris XI, Paris VI, l'Ecole des Mines de Paris, l'Ecole Centrale de Pari s et l'INSTN, sont invités à participer à ce colloque et aux débats scientifiques qui s'y déroulent. Des conférences invitées à caractère péda gogique permettent d'introduire les différents thèmes abordés qui sont ensuite développés dans des présentations plus novatrices. Cette manifestation a pour ambition de favoriser la rencontre de scientifiques d'horizons divers venant de milieux académiques ou industriels entre eux et avec les étudiants et thésards. Cette 44e édition, dont les comptes rendus sont publiés ici, a fait le point sur les problèmes de matériaux rencontrés lors de la production, du stockage et de la conversion des énergies dites propres en englobant lesprogrès constants des industriels de l'automobile. Ce colloque a réuni, du 26 au 28 juin 2001, 63 participants provenant d'universités ou grandes écoles (18), du CEA (17), du CNRS (10) et de l'industrie ou de centres de recherche associés. L'ensemble des problèmes de matériaux de ce secteur ont été examinés au cours des six sessions ci-dessous : dépollution des gaz d'échappement ; combustion catalytique en production thermique ; nouvelles batteries ; piles à combustibles ; production et stockage d'hydrogène ; production et stockage d'énergie solaire. Vingt huit communications dont vingt deux orales ont illustré les dével oppements en cours. Dix

  11. Two Cases of Transiently Elevated Serum CEA Levels in Severe Hypothyroidism without Goiter.

    PubMed

    Sekizaki, Tomonori; Yamamoto, Chiho; Nomoto, Hiroshi

    2018-04-27

    Carcinoembryonic antigen (CEA), the level of which is known to increase in both patients with gastrointestinal cancers and those with non-neoplastic conditions, is one of the most widely-used tumor markers. Hypothyroidism is a common endocrinological disorder in which CEA levels can rise, and is sometimes overlooked as a diagnosis in the absence of typical symptoms or thyroid enlargement. We report the cases of two patients with non-goiterous severe hypothyroidism with markedly elevated CEA levels that effectively decreased with levothyroxine replacement therapy alone. Hypothyroidism should be considered as an important cause of unexplained high serum CEA levels in order to avoid unnecessary medical examination.

  12. A Cafe Scientifique for Teens

    NASA Astrophysics Data System (ADS)

    Hall, M.; Mayhew, M.

    2008-12-01

    It is well-known to those pursuing the quest to connect scientists to the public that an exceedingly hard-to- reach demographic is people of high school age. Typically, kids may tag along with their parents to museums until they reach adolescence, and then don't again appear in museums until they themselves have children. We have addressed this demographic challenge for free-choice-learning by developing a Cafe Scientifique program specifically for high school students. The Cafe Scientifique model for adults was developed in England and France, and has now spread like wildfire across the U.S. Typically, people come to a informal setting like a cafe, socialize and have food and drink, and then hear a short presentation by a scientist on a hot science topic in the news. This is followed by a period of lively discussion. We have followed this model for high school age students in four towns in northern New Mexico--Los Alamos, Santa Fe, Espanola, and Albuquerque--which represent a highly diverse demographic. We started this novel project with some trepidation, i.e. what if we build it and they don't come. But the program has proven popular beyond our expectations in all four towns. A part of the secret of success is the social setting, and-especially for this age group-the food provided. But we have also found that the kids are genuinely interested in the science topics, directing their own program, and interacting with scientists. We have often heard statements like, "I think it is important to be well-informed citizens". One of the most important aspects of the Cafes for the kids is to be able to discuss and argue about issues related to the science topic with the presenter and each other. It is an important part of the popularity that the Cafes do not involve school or parents, but also that we have strived to give the kids ownership of the program. Each town has a Youth Leadership Team-open to any teen-that discusses and prioritizes potential topics, conducts

  13. Complete solid state lighting (SSL) line at CEA LETI

    NASA Astrophysics Data System (ADS)

    Robin, I. C.; Ferret, P.; Dussaigne, A.; Bougerol, C.; Salomon, D.; Chen, X. J.; Charles, M.; Tchoulfian, P.; Gasse, A.; Lagrange, A.; Consonni, M.; Bono, H.; Levy, F.; Desieres, Y.; Aitmani, A.; Makram-Matta, S.; Bialic, E.; Gorrochategui, P.; Mendizabal, L.

    2014-09-01

    With a long experience in optoelectronics, CEA-LETI has focused on Light Emitting Diode (LED) lighting since 2006. Today, all the technical challenges in the implementation of GaN LED based solid state lighting (SSL) are addressed at CEA-LETI who is now an RandD player throughout the entire value chain of LED lighting. The SSL Line at CEA-LETI first deals with the simulation of the active structures and LED devices. Then the growth is addressed in particular 2D growth on 200 mm silicon substrates. Then, technological steps are developed for the fabrication of LED dies with innovative architectures. For instance, Versatile LED Array Devices are currently being developed with a dedicated μLED technology. The objective in this case is to achieve monolithical LED arrays reported and interconnected through a silicon submount. In addition to the required bonding and 3D integration technologies, new solutions for LED chip packaging, thermal management of LED lamps and luminaires are also addressed. LETI is also active in Smart Lighting concepts which offer the possibility of new application fields for SSL technologies. An example is the recent development at CEA LETI of Visible Light Communication Technology also called LiFi. With this technology, we demonstrated a transmission rate up to 10 Mb/s and real time HD-Video transmission.

  14. Aeroacoustics research in Europe: The CEAS-ASC report on 2016 highlights

    NASA Astrophysics Data System (ADS)

    Wilson, Alexander G.

    2018-08-01

    The Council of European Aerospace Societies (CEAS) Aeroacoustics Specialists Committee (ASC) supports and promotes the interests of the scientific and industrial aeroacoustics community on the European scale, and European aeronautics activities internationally. Each year, the committee highlights several of the research and development projects in Europe. This paper is the 2016 issue of this collection of Aeroacoustic Highlights, compiled from contributions submitted to the CEAS-ASC. The contributions are classified under three main headings; Aircraft and Turbomachinery Noise, Experimental and Numerical Methods and Further Applications of Aeroacoustics. A concise summary of the CEAS-ASC workshop held in Southampton, England, in September 2016 is also included in this report.

  15. Diagnostic test pepsinogen I and combination with tumor marker CEA in gastric cancer

    NASA Astrophysics Data System (ADS)

    Sembiring, J.; Sarumpaet, K.; Ganie, R. A.

    2018-03-01

    Gastric cancer (GC) is the fifth leading cause of cancer and the third leading cause of cancer-related mortality globally. Human pepsinogens (HP) are considered promising serological biomarkers for the screening of atrophic gastritis (AG) and GC. HP are biochemically and immunochemically classified into two groups: pepsinogen I (PG I) and PG II. Carcinoembryonic antigen (CEA) is a glycoprotein, which is present in normal mucosal cells but increased amounts are associated with adenocarcinoma, especially colorectal cancer. CEA in combination with other tumour markers can be used in pre-operative staging and thereby assist in the planning of the type of surgery required and future management options. The purpose of this study was to diagnose test PG I and combination with tumor marker CEA in 32 patients suspected with GC. There was a significant difference in levels of CEA between GC group with non-GC with a value p <0.001. PGI sensitivity was 70.58% and specificity 93.3%. The sensitivity of PGI and CEA combination of 94.1% and specificity 80%. The area of AUC obtained was 92.7% at 95% confidence interval (82.7-100%). This AUC value indicated that the value of diagnostic accuracy of the PGI and CEA combinations of 92.7%.

  16. Anti-CEA-functionalized superparamagnetic iron oxide nanoparticles for examining colorectal tumors in vivo

    NASA Astrophysics Data System (ADS)

    Huang, Kai-Wen; Chieh, Jen-Jie; Lin, In-Tsang; Horng, Herng-Er; Yang, Hong-Chang; Hong, Chin-Yih

    2013-10-01

    Although the biomarker carcinoembryonic antigen (CEA) is expressed in colorectal tumors, the utility of an anti-CEA-functionalized image medium is powerful for in vivo positioning of colorectal tumors. With a risk of superparamagnetic iron oxide nanoparticles (SPIONPs) that is lower for animals than other material carriers, anti-CEA-functionalized SPIONPs were synthesized in this study for labeling colorectal tumors by conducting different preoperatively and intraoperatively in vivo examinations. In magnetic resonance imaging (MRI), the image variation of colorectal tumors reached the maximum at approximately 24 h. However, because MRI requires a nonmetal environment, it was limited to preoperative imaging. With the potentiality of in vivo screening and intraoperative positioning during surgery, the scanning superconducting-quantum-interference-device biosusceptometry (SSB) was adopted, showing the favorable agreement of time-varied intensity with MRI. Furthermore, biological methodologies of different tissue staining methods and inductively coupled plasma (ICP) yielded consistent results, proving that the obtained in vivo results occurred because of targeted anti-CEA SPIONPs. This indicates that developed anti-CEA SPIONPs owe the utilities as an image medium of these in vivo methodologies.

  17. Significance of CEA and VEGF as Diagnostic Markers of Colorectal Cancer in Lebanese Patients.

    PubMed

    Dbouk, Hashem A; Tawil, Ayman; Nasr, Fahd; Kandakarjian, Loucine; Abou-Merhi, Raghida

    2007-11-08

    Carcinoembryonic antigen and vascular endothelial growth factors are among the most important prognostic markers of colorectal cancer. Testing for these markers independently has been of limited value in screening for this tumor. The aim of this study is to determine the importance of simultaneous blood CEA and VEGF level determinations in diagnosis of colorectal cancer. Thirty-six patients diagnosed with colorectal cancer along with eight healthy controls were tested by ELISA for CEA and VEGF levels in serum and plasma, respectively. The positive predictive value of these markers was 95.4% for CEA and 89.5% for VEGF, and for combined CEA and VEGF was also high at 88%. Combined CEA and VEGF blood level assay constitutes a useful panel in detecting patients with colorectal cancer. Positive results allow selection of a subgroup of patients with a high tumor risk; therefore, such tests comprise valuable tumor diagnostic tests to add to current detection methods.

  18. Hookah smoking and cancer: carcinoembryonic antigen (CEA) levels in exclusive/ever hookah smokers.

    PubMed

    Sajid, Khan Mohammad; Chaouachi, Kamal; Mahmood, Rubaida

    2008-05-24

    We have recently published some work on CEA levels in hookah (also called narghile, shisha elsewhere) and cigarette smokers. Hookah smokers had higher levels of CEA than non-smokers although mean levels were low compared to cigarette smokers. However some of them were also users of other tobacco products (cigarettes, bidis, etc.). To find serum CEA levels in ever/exclusive hookah smokers, i.e. those who smoked only hookah (no cigarettes, bidis, etc.), prepared between 1 and 4 times a day with a quantity of up to 120 g of a tobacco-molasses mixture each (i.e. the tobacco weight equivalent of up to 60 cigarettes of 1 g each) and consumed in 1 to 8 sessions. Enhanced chemiluminescent immunometric technique was applied to measure CEA levels in serum samples from 59 exclusive male smokers with age ranging from 20-80 years (mean = 58.8 +/- 14.7 years) and 8-65 years of smoking (mean = 37.7 +/- 16.8). 36 non-smokers served as controls. Subjects were divided into 3 groups according to the number of preparations; the number of sessions and the total daily smoking time: Light (1; 1; < or = 20 minutes); Medium (1-3; 1-3; >20 min to < or = 2 hrs) and Heavy smokers (2-4; 3-8; >2 hrs to < or = 6 hrs). Because of the nature of distribution of CEA levels among our individuals, Wilcoxon's rank sum two-sample test was applied to compare the variables. The overall CEA levels in exclusive hookah smokers (mean: 3.58 +/- 2.61 ng/ml; n = 59) were not significantly different (p < or = 0.0937) from the levels in non-smokers (2.35 +/- 0.71 ng/ml). Mean levels in light, medium and heavy smokers were: 1.06 +/- 0.492 ng/ml (n = 5); 2.52 +/- 1.15 ng/ml (n = 28) and 5.11 +/- 3.08 ng/ml (n = 26) respectively. The levels in medium smokers and non-smokers were also not significantly different (p < or = 0.9138). In heavy smokers, the CEA levels were significantly higher than in non-smokers (p < or = 0.0001567). Overall CEA levels in exclusive hookah smokers were low compared to cigarette smokers

  19. Serum CEA levels in patients with gastric carcinoma correlate with the tumorigenicity of their xenografts in nude mice.

    PubMed

    Kiyama, T; Onda, M; Tokunaga, A; Okuda, T; Mizutani, T; Yoshiyuki, T; Shimizu, Y; Nishi, K; Matsukura, N; Tanaka, N

    1991-01-01

    We examined the correlation among preoperative serum carcinoembryonic antigen (CEA) levels, staining properties of the tumors by CEA immunohistochemistry and the tumorigenicity of their xenografts in nude mice, in 28 patients with gastric cancer. Eleven (40 per cent) of them were positive for serum CEA (greater than or equal to 2.5 ng/ml) and seven (25 per cent) of the xenografts were tumorigenic in nude mice. All the tumorigenic cases were positive for serum CEA (p less than 0.001) and the mean value of the serum CEA level in the patients with tumorigenic neoplasms was 20.8 ng/ml, being significantly higher than that (1.4 ng/ml) in the patients with non-tumorigenic neoplasms (p less than 0.001). Twenty-five of the 28 carcinomas (89 per cent) were positive for CEA staining in their cancer cells by the ABC method and CEA localization correlated with tumorigenicity (p less than 0.05). These results suggest that the serum CEA level in patients is correlated with the tumorigenicity of their gastric carcinoma xenografts in nude mice and may account for the poor prognosis of patients with high serum CEA.

  20. Hookah smoking and cancer: carcinoembryonic antigen (CEA) levels in exclusive/ever hookah smokers

    PubMed Central

    Sajid, Khan Mohammad; Chaouachi, Kamal; Mahmood, Rubaida

    2008-01-01

    Background We have recently published some work on CEA levels in hookah (also called narghile, shisha elsewhere) and cigarette smokers. Hookah smokers had higher levels of CEA than non-smokers although mean levels were low compared to cigarette smokers. However some of them were also users of other tobacco products (cigarettes, bidis, etc.). Objectives To find serum CEA levels in ever/exclusive hookah smokers, i.e. those who smoked only hookah (no cigarettes, bidis, etc.), prepared between 1 and 4 times a day with a quantity of up to 120 g of a tobacco-molasses mixture each (i.e. the tobacco weight equivalent of up to 60 cigarettes of 1 g each) and consumed in 1 to 8 sessions. Methods Enhanced chemiluminescent immunometric technique was applied to measure CEA levels in serum samples from 59 exclusive male smokers with age ranging from 20–80 years (mean = 58.8 ± 14.7 years) and 8–65 years of smoking (mean = 37.7 ± 16.8). 36 non-smokers served as controls. Subjects were divided into 3 groups according to the number of preparations; the number of sessions and the total daily smoking time: Light (1; 1; ≤ 20 minutes); Medium (1–3; 1–3; >20 min to ≤ 2 hrs) and Heavy smokers (2–4; 3–8; >2 hrs to ≤ 6 hrs). Because of the nature of distribution of CEA levels among our individuals, Wilcoxon's rank sum two-sample test was applied to compare the variables. Results The overall CEA levels in exclusive hookah smokers (mean: 3.58 ± 2.61 ng/ml; n = 59) were not significantly different (p ≤ 0.0937) from the levels in non-smokers (2.35 ± 0.71 ng/ml). Mean levels in light, medium and heavy smokers were: 1.06 ± 0.492 ng/ml (n = 5); 2.52 ± 1.15 ng/ml (n = 28) and 5.11 ± 3.08 ng/ml (n = 26) respectively. The levels in medium smokers and non-smokers were also not significantly different (p ≤ 0.9138). In heavy smokers, the CEA levels were significantly higher than in non-smokers (p ≤ 0.0001567). Conclusion Overall CEA levels in exclusive hookah smokers were

  1. Magnetic susceptibilities of liquid Cr-Au, Mn-Au and Fe-Au alloys

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ohno, S.; Shimakura, H.; Tahara, S.

    The magnetic susceptibility of liquid Cr-Au, Mn-Au, Fe-Au and Cu-Au alloys was investigated as a function of temperature and composition. Liquid Cr{sub 1-c}Au{sub c} with 0.5 ≤ c and Mn{sub 1-c}Au{sub c} with 0.3≤c obeyed the Curie-Weiss law with regard to their dependence of χ on temperature. The magnetic susceptibilities of liquid Fe-Au alloys also exhibited Curie-Weiss behavior with a reasonable value for the effective number of Bohr magneton. On the Au-rich side, the composition dependence of χ for liquid TM-Au (TM=Cr, Mn, Fe) alloys increased rapidly with increasing TM content, respectively. Additionally, the composition dependences of χ for liquidmore » Cr-Au, Mn-Au, and Fe-Au alloys had maxima at compositions of 50 at% Cr, 70 at% Mn, and 85 at% Fe, respectively. We compared the composition dependences of χ{sub 3d} due to 3d electrons for liquid binary TM-M (M=Au, Al, Si, Sb), and investigated the relationship between χ{sub 3d} and E{sub F} in liquid binary TM-M alloys at a composition of 50 at% TM.« less

  2. Prospective randomised trial of early cytotoxic therapy for recurrent colorectal carcinoma detected by serum CEA.

    PubMed Central

    Hine, K R; Dykes, P W

    1984-01-01

    Of 663 patients treated with radical surgery for colorectal cancer, 52 showed a progressive rise in serum carcinoembryonic antigen (CEA) with no other evidence of recurrent disease and were randomised in a prospective study of chemotherapy. Twenty six patients in the treatment group received 5FU and methyl CCNU from the time of randomisation and the remaining 26 controls were given further therapy only if there were clinical indications. All patients were followed for five years or until their death and all but one (control) developed clinical evidence of recurrence. Overall there was no significant difference between the two groups with respect to disease free interval and survival. Whereas the rise in CEA in controls was generally progressive, marked inflections on the CEA curves were seen in the majority of patients receiving early treatment. Eight of 26 treated patients showed a fall in CEA of greater than 20% two months after starting therapy. These patients had a median disease free interval of 90 weeks and a median survival of 107 weeks, these figures being longer than those of treated patients who did not show a fall in CEA and control patients. The serum CEA therefore appeared to give important prognostic information in patients receiving cytotoxic treatment. Early therapy was generally well tolerated. PMID:6376291

  3. Uropathogenic E. coli Exploit CEA to Promote Colonization of the Urogenital Tract Mucosa

    PubMed Central

    Muenzner, Petra; Kengmo Tchoupa, Arnaud; Klauser, Benedikt; Brunner, Thomas; Putze, Johannes; Dobrindt, Ulrich; Hauck, Christof R.

    2016-01-01

    Attachment to the host mucosa is a key step in bacterial pathogenesis. On the apical surface of epithelial cells, members of the human carcinoembryonic antigen (CEA) family are abundant glycoproteins involved in cell-cell adhesion and modulation of cell signaling. Interestingly, several gram-negative bacterial pathogens target these receptors by specialized adhesins. The prototype of a CEACAM-binding pathogen, Neisseria gonorrhoeae, utilizes colony opacity associated (Opa) proteins to engage CEA, as well as the CEA-related cell adhesion molecules CEACAM1 and CEACAM6 on human epithelial cells. By heterologous expression of neisserial Opa proteins in non-pathogenic E. coli we find that the Opa protein-CEA interaction is sufficient to alter gene expression, to increase integrin activity and to promote matrix adhesion of infected cervical carcinoma cells and immortalized vaginal epithelial cells in vitro. These CEA-triggered events translate in suppression of exfoliation and improved colonization of the urogenital tract by Opa protein-expressing E. coli in CEA-transgenic compared to wildtype mice. Interestingly, uropathogenic E. coli expressing an unrelated CEACAM-binding protein of the Afa/Dr adhesin family recapitulate the in vitro and in vivo phenotype. In contrast, an isogenic strain lacking the CEACAM-binding adhesin shows reduced colonization and does not suppress epithelial exfoliation. These results demonstrate that engagement of human CEACAMs by distinct bacterial adhesins is sufficient to blunt exfoliation and to promote host infection. Our findings provide novel insight into mucosal colonization by a common UPEC pathotype and help to explain why human CEACAMs are a preferred epithelial target structure for diverse gram-negative bacteria to establish a foothold on the human mucosa. PMID:27171273

  4. Comparison of Ablation Predictions for Carbonaceous Materials Using CEA and JANAF-Based Species Thermodynamics

    NASA Technical Reports Server (NTRS)

    Milos, Frank S.

    2011-01-01

    In most previous work at NASA Ames Research Center, ablation predictions for carbonaceous materials were obtained using a species thermodynamics database developed by Aerotherm Corporation. This database is derived mostly from the JANAF thermochemical tables. However, the CEA thermodynamics database, also used by NASA, is considered more up to date. In this work, the FIAT code was modified to use CEA-based curve fits for species thermodynamics, then analyses using both the JANAF and CEA thermodynamics were performed for carbon and carbon phenolic materials over a range of test conditions. The ablation predictions are comparable at lower heat fluxes where the dominant mechanism is carbon oxidation. However, the predictions begin to diverge in the sublimation regime, with the CEA model predicting lower recession. The disagreement is more significant for carbon phenolic than for carbon, and this difference is attributed to hydrocarbon species that may contribute to the ablation rate.

  5. Association of CA 15-3 and CEA with clinicopathological parameters in patients with metastatic breast cancer.

    PubMed

    Geng, Biao; Liang, Man-Man; Ye, Xiao-Bing; Zhao, Wen-Ying

    2015-01-01

    The objective of this study was to investigate the association of serum cancer antigen 15-3 (CA 15-3) and carcinoembryonic antigen (CEA) levels with clinicopathological parameters in patients diagnosed with metastatic breast cancer (MBC). We retrospectively evaluated the medical records of 284 patients diagnosed with MBC between January, 2007 and December, 2012 who fulfilled the specified criteria and the association between the levels of the two tumor marker and clinicopathological parameters was analyzed. Of the 284 patients, elevated CA 15-3 and CEA levels at initial diagnosis of recurrence were identified in 163 (57.4%) and 97 (34.2%) patients, respectively. Elevated CA 15-3 and CEA levels were significantly associated with breast cancer molecular subtypes (P<0.001 and P=0.032, respectively). Cases with luminal subtypes exhibited a higher percentage of elevated CA 15-3 and CEA levels compared to non-luminal subtypes. Elevated CA 15-3 level was correlated with bone metastasis (P=0.017). However, elevation of CEA was observed regardless of the site of metastasis. Elevation of CA 15-3 was significantly more common in MBC with multiple metastatic sites compared to MBC with a single metastasis (P=0.001). However, the incidence of elevated CEA levels did not differ between patients with a single and those with multiple metastatic sites. In conclusion, elevated CA 15-3 and CEA levels at initial diagnosis of recurrence were found to be associated with breast cancer molecular subtypes, whereas an elevated CA 15-3 level was significantly correlated with bone metastasis and an elevated CEA level was observed regardless of metastatic site. The proportion of MBC cases with elevated CA 15-3 levels differed according to the number of metastatic sites.

  6. Multiple myeloma presenting as CEA-producing rectal cancer.

    PubMed

    Talamo, Giampaolo; Barochia, Amitkumar; Zangari, Maurizio; Loughran, Thomas P

    2010-03-31

    We report the case of a 57-year-old patient with multiple myeloma, characterized by extramedullary involvement of the rectum at presentation. Malignant plasma cells were found to produce carcinoembryonic antigen (CEA), a tumor antigen more commonly associated with rectal adenocarcinomas.

  7. The value of KRAS mutation testing with CEA for the diagnosis of pancreatic mucinous cysts

    PubMed Central

    Kadayifci, Abdurrahman; Al-Haddad, Mohammad; Atar, Mustafa; Dewitt, John M.; Forcione, David G.; Sherman, Stuart; Casey, Brenna W.; Fernandez-del Castillo, Carlos; Schmidt, C. Max; Pitman, Martha B.; Brugge, William R.

    2016-01-01

    Background and aims: Pancreatic cyst fluid (PCF) CEA has been shown to be the most accurate preoperative test for detection of cystic mucinous neoplasms (CMNs). This study aimed to assess the added value of PCF KRAS mutational analysis to CEA for diagnosis of CMNs. Patients and methods: This is a retrospective study of prospectively collected endoscopic ultrasonography (EUS) fine-needle aspiration (FNA) data. KRAS mutation was determined by direct sequencing or equivalent methods. Cysts were classified histologically (surgical cohort) or by clinical (EUS or FNA) findings (clinical cohort). Performance characteristics of KRAS, CEA and their combination for detection of a cystic mucinous neoplasm (CMN) and malignancy were calculated. Results: The study cohort consisted of 943 patients: 147 in the surgical cohort and 796 in the clinical cohort. Overall, KRAS and CEA each had high specificity (100 % and 93.2 %), but low sensitivity (48.3 % and 56.3 %) for the diagnosis of a CMN. The positivity of KRAS or CEA increased the diagnostic accuracy (80.8 %) and AUC (0.84) significantly compared to KRAS (65.3 % and 0.74) or CEA (65.8 % and 0.74) alone, but only in the clinical cohort (P < 0.0001 for both). KRAS mutation was significantly more frequent in malignant CMNs compared to histologically confirmed non-malignant CMNs (73 % vs. 37 %, P = 0.001). The negative predictive value of KRAS mutation was 77.6 % in differentiating non-malignant cysts. Conclusions: The detection of a KRAS mutation in PCF is a highly specific test for mucinous cysts. It outperforms CEA for sensitivity in mucinous cyst diagnosis, but the data does not support its routine use. PMID:27092317

  8. Multiple myeloma presenting as CEA-producing rectal cancer

    PubMed Central

    Talamo, Giampaolo; Barochia, Amitkumar; Zangari, Maurizio; Loughran, Thomas P

    2010-01-01

    We report the case of a 57-year-old patient with multiple myeloma, characterized by extramedullary involvement of the rectum at presentation. Malignant plasma cells were found to produce carcinoembryonic antigen (CEA), a tumor antigen more commonly associated with rectal adenocarcinomas. PMID:21139949

  9. Efficient double-quenching of electrochemiluminescence from CdS:Eu QDs by hemin-graphene-Au nanorods ternary composite for ultrasensitive immunoassay

    PubMed Central

    Liu, Jing; Cui, Meirong; Zhou, Hong; Zhang, Shusheng

    2016-01-01

    A novel ternary composite of hemin-graphene-Au nanorods (H-RGO-Au NRs) with high electrocatalytic activity was synthesized by a simple method. And this ternary composite was firstly used in construction of electrochemiluminescence (ECL) immunosensor due to its double-quenching effect of quantum dots (QDs). Based on the high electrocatalytic activity of ternary complexes for the reduction of H2O2 which acted as the coreactant of QDs-based ECL, as a result, the ECL intensity of QDs decreased. Besides, due to the ECL resonance energy transfer (ECL-RET) strategy between the large amount of Au nanorods (Au NRs) on the ternary composite surface and the CdS:Eu QDs, the ECL intensity of QDs was further quenched. Based on the double-quenching effect, a novel ultrasensitive ECL immunoassay method for detection of carcinoembryonic antigen (CEA) which is used as a model biomarker analyte was proposed. The designed immunoassay method showed a linear range from 0.01 pg mL−1 to 1.0 ng mL−1 with a detection limit of 0.01 pg mL−1. The method showing low detection limit, good stability and acceptable fabrication reproducibility, provided a new approach for ECL immunoassay sensing and significant prospect for practical application. PMID:27460868

  10. Evaluation of serum CA27.29, CA15-3 and CEA in patients with breast cancer.

    PubMed

    Hou, M F; Chen, Y L; Tseng, T F; Lin, C M; Chen, M S; Huang, C J; Huang, Y S; Hsieh, J S; Huang, T J; Jong, S B; Huang, Y F

    1999-09-01

    The Truquant BR radioimmunoassay (RIA) using monoclonal antibody BR 27.29 to recognize a peptide sequence on the MUC-1 gene product for quantification of the CA 27.29 antigen in serum was used in this report to evaluate in 145 patients with breast cancer and compared the other conventional serum markers such as CA15-3 and CEA. The upper limit of normal (25 u/ml) was determined from CA27.29 values 12.4 +/- 4.1 u/ml (mean +/- 3 S.D.) for 112 female subjects apparently free of disease. The CA15-3 levels above 25 u/ml and CEA levels above 5 ng/ml were considered positive values. Thirty-seven cases of 145 patients studied had elevated CA 27.29 levels (sensitivity: 25.5%), 35 of 145 had positive CA15-3 levels (sensitivity 24.1%) and 27 of 145 patients had positive CEA levels (sensitivity: 18.6%) (p < 0.05). One hundred and ten cases of the breast cancer patients (75.8%) did not have metastatic disease. In this group CA 27.29 sensitivity was 6.4%, while CA15-3 sensitivity was 5.5% and CEA sensitivity was 4.5% (p > 0.05). Mean values were 10.2 +/- 9.2 u/ml for CA 27.29, 14.1 +/- 5.6 u/ml for CA 15-3 and 1.7 +/- 1.5 ng/ml for CEA. Thirty-five patients (24.2%) had metastatic disease. In this group CA 27.29 sensitivity was 85.7%, CA15-3 sensitivity was 82.8% and CEA sensitivity was 62.8% (p < 0.05). Mean values for CA27.29 was 152.6 +/- 131.6 u/ml, CA15-3 was 123.1 +/- 107.6 u/ml and 21.8 +/- 36.9 ng/ml of CEA. With regard to the correlation of three tumor markers with clinical stages, patients had significantly higher levels of CA27.29 than CEA, but they were similar to CA 15-3 in metastatic breast cancer. These results suggest CA27.29 to be more sensitive and specific than CEA, but that it is similar to CA15-3 for metastatic breast cancer detection and monitoring.

  11. Evaluation of predictive value of pleural CEA in patients with pleural effusions and histological findings: A prospective study and literature review.

    PubMed

    Tozzoli, Renato; Basso, Stefano M M; D'Aurizio, Federica; Metus, Paolo; Lumachi, Franco

    2016-11-01

    Pleural effusion recognizes heterogeneous etiology and pathogenesis and requires invasive diagnostic procedures. Usually, after pleural fluid analysis, 30-50% of patients with malignant pleural effusion exhibit negative pleural cytology, and the sensitivity of image-guided pleural needle-aspiration biopsy ranges between 60% and 70%. With the aim of differentiating between benign (BPE) and malignant (MPE) pleural effusions, several tumor markers have been assayed in the pleural fluid and the majority of studies focus on pleural carcinoembryonic antigen (p-CEA). The aims of this study were to evaluate (i) the diagnostic accuracy of p-CEA of patients with pleural effusions undergoing video-assisted thoracoscopic surgery (VATS) for diagnostic purpose, (ii) the relationship between p-CEA and serum CEA (s-CEA), and (iii) the usefulness of the p-CEA/s-CEA ratio in the diagnosis of malignant pleural effusions (MPE). We prospectively enrolled in the study 134 consecutive patients with pleural effusions, scheduled for having VATS and biopsy. The final diagnosis, based on histopathology of the VATS-guided specimens, was available for all patients. p-CEA and s-CEA was assayed with a chemiluminescence immunoassay method (CLIA), applied on the Maglumi 2000 Plus automated platform (SNIBE, Shenzen, China). The sensitivity and accuracy of p-CEA was significantly higher than that of pleural cytology at the same specificity comparing BPE with MPE and BPE with non-small lung cancer. The sensitivity of p-CEA and PC together reached 100% (BPE vs. NSCLC) and 91.5% (BPE vs. MPE excluding mesothelioma), respectively. The p-CEA measurement in patients with pleural effusion of uncertain etiology is a safe and cost-effective procedure, everywhere easily available, which may help clinicians in selecting patients for further evaluations. An elevated p-CEA level in a patient with pleural effusion and negative pleural cytology suggests the need of more invasive procedure (e.g. VATS

  12. Préface

    NASA Astrophysics Data System (ADS)

    Ouerdane, Youcef; Laporte, Pierre

    2005-06-01

    ère sur onduleurs et 22 sur aimants de courbure. Les premiers “utilisateurs” sont prévus au printemps 2006 avec couverture de l'IR jusqu'aux X durs pour des études variées notamment dans le domaine de la matière condensée. - La LIL (ligne d'intégration laser) du LMJ fonctionne avec 4 faisceaux (de 30 kJ à 351 nm) et un ensemble de diagnostics plasma est en cours de validation (énergie, imagerie X, spectrométrie X). Un souci d'ouverture collaborative (France et étranger) est affiché. - LASERIX (LIXAM, LOA) a pour but de doter les scientifiques français d'un laser émettant en “quasi-routine” de l'émission laser X à 6 tirs/mn basée sur différents schémas collisionnels et donc différentes longueurs d'ondes, et mettant en oeuvre un laser saphir-titane ultra bref de 40 J pour la génération plasma. - Le projet Arc en Ciel (CEA, LOA) se penche sur la possibilité de mise en oeuvre d'une source de “4^ogénération”. Ces sources se veulent à la fois brillantes, cohérentes, dans la gamme des 100 femtosecondes, ce qui conduit à tourner le dos aux anneaux de stockage pour se focaliser sur la combinaison accélérateur linéaire/onduleur, complétée par un laser saphir-titane (génération d'harmoniques UV/X dans des gaz). - Une avancée particulièrement intéressante a été récemment réalisée, notamment au LOA, par injection d'un laser X (plasma) par un faisceau X de bonne qualité (polarisation, divergence, temps, contraste...) issu de la génération d'harmoniques élevées par une chaîne saphir-titane femto. - On notera aussi les avancées réalisées dans le domaine des sources incohérentes de forte intensité dans le domaine des X par interaction optimisée de l'interaction laser de puissance-agrégats (GPS-Paris 6 et 7, CEA Saclay), ainsi que par techniques X-pinch à fils à foyer de 10 microns (LPTP-École Polytechnique). - La génération d'harmoniques d'ordres élevés à partir de chaînes laser amplifiées a continué à faire l

  13. Label-free fluorimetric detection of CEA using carbon dots derived from tomato juice.

    PubMed

    Miao, Hong; Wang, Lan; Zhuo, Yan; Zhou, Zinan; Yang, Xiaoming

    2016-12-15

    A facile-green strategy to synthesize carbon dots (CDs) with a quantum yield (QY) of nearly 13.9% has been built up, while tomato juice served as the carbon source. Interestingly, not only the precursor of CDs and the whole synthesis procedure were environmental-friendly, but this type of CDs also exhibited multiple advantages including high fluorescent QY, excellent photostability, non-toxicity and satisfactory stability. Significantly, a label-free sensitive assay for detecting carcinoembryonic antigen (CEA) in a continuous and recyclable way has been proposed on the basis of adsorption and desorption of aptamers by the surface of CDs through a competitive mechanism. To be specific, the richness of carboxyl groups of the CDs enabled strong adsorption of ssDNA to the surface of CDs through π-π stacking interactions, resulting in the effective fluorescence quenching by forming CDs-aptamer complexes. The stronger binding affinity between CEA and CEA-aptamer than the π-π stacking interactions has been taken advantage to achieve immediate recovery of the fluorescence of CDs once CEA was introduced. Thereby, quantitative evaluation of CEA concentration in a broad range from 1ngmL(-1) to 0.5ngmL(-1) with the detection limit of 0.3ngmL(-1) was realized in this way. This strategy can be applied in a recyclable way, broadening the sensing application of CDs with biocompatibility. Besides, the CDs were used for cell imaging, potentiating them towards diverse purposes. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. From the ternary Eu(Au/In) 2 and EuAu 4(Au/In) 2 with remarkable Au/In distributions to a new structure type: The gold-rich Eu 5Au 16(Au/In) 6 structure

    DOE PAGES

    Steinberg, Simon; Card, Nathan; Mudring, Anja -Verena

    2015-08-13

    The ternary Eu(Au/In) 2 (EuAu 0.46In 1.54 (2)) (I), EuAu 4(Au/In) 2 (EuAu 4+xIn 2–x with x = 0.75(2) (II), 0.93(2), and 1.03(2)), and Eu 5Au 16(Au/In) 6 (Eu 5Au 17.29In 4.71(3)) (III) have been synthesized, and their structures were characterized by single-crystal X-ray diffraction. I and II crystallize with the CeCu 2-type (Pearson Symbol oI12; Imma; Z = 4; a = 4.9018(4) Å; b = 7.8237(5) Å; c = 8.4457(5) Å) and the YbAl 4Mo 2-type (tI14; I4/ mmm; Z = 2; a = 7.1612(7) Å; c = 5.5268(7) Å) and exhibit significant Au/In disorder. I is composed ofmore » an Au/In-mixed diamond-related host lattice encapsulating Eu atoms, while the structure of II features ribbons of distorted, squared Au 8 prisms enclosing Eu, Au, and In atoms. Combination of these structural motifs leads to a new structure type as observed for Eu 5Au 16(Au/In) 6 (Eu 5Au 17.29In 4.71(3)) (oS108; Cmcm; Z = 4; a = 7.2283(4) Å; b = 9.0499(6) Å; c = 34.619(2) Å), which formally represents a one-dimensional intergrowth of the series EuAu 2–“EuAu 4In 2”. The site preferences of the disordered Au/In positions in II were investigated for different hypothetical “EuAu 4(Au/In) 2” models using the projector-augmented wave method and indicate that these structures attempt to optimize the frequencies of the heteroatomic Au–In contacts. Furthermore, a chemical bonding analysis on two “EuAu 5In” and “EuAu 4In 2” models employed the TB-LMTO-ASA method and reveals that the subtle interplay between the local atomic environments and the bond energies determines the structural and site preferences for these systems.« less

  15. From the ternary Eu(Au/In) 2 and EuAu 4(Au/In) 2 with remarkable Au/In distributions to a new structure type: The gold-rich Eu 5Au 16(Au/In) 6 structure

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Steinberg, Simon; Card, Nathan; Mudring, Anja -Verena

    The ternary Eu(Au/In) 2 (EuAu 0.46In 1.54 (2)) (I), EuAu 4(Au/In) 2 (EuAu 4+xIn 2–x with x = 0.75(2) (II), 0.93(2), and 1.03(2)), and Eu 5Au 16(Au/In) 6 (Eu 5Au 17.29In 4.71(3)) (III) have been synthesized, and their structures were characterized by single-crystal X-ray diffraction. I and II crystallize with the CeCu 2-type (Pearson Symbol oI12; Imma; Z = 4; a = 4.9018(4) Å; b = 7.8237(5) Å; c = 8.4457(5) Å) and the YbAl 4Mo 2-type (tI14; I4/ mmm; Z = 2; a = 7.1612(7) Å; c = 5.5268(7) Å) and exhibit significant Au/In disorder. I is composed ofmore » an Au/In-mixed diamond-related host lattice encapsulating Eu atoms, while the structure of II features ribbons of distorted, squared Au 8 prisms enclosing Eu, Au, and In atoms. Combination of these structural motifs leads to a new structure type as observed for Eu 5Au 16(Au/In) 6 (Eu 5Au 17.29In 4.71(3)) (oS108; Cmcm; Z = 4; a = 7.2283(4) Å; b = 9.0499(6) Å; c = 34.619(2) Å), which formally represents a one-dimensional intergrowth of the series EuAu 2–“EuAu 4In 2”. The site preferences of the disordered Au/In positions in II were investigated for different hypothetical “EuAu 4(Au/In) 2” models using the projector-augmented wave method and indicate that these structures attempt to optimize the frequencies of the heteroatomic Au–In contacts. Furthermore, a chemical bonding analysis on two “EuAu 5In” and “EuAu 4In 2” models employed the TB-LMTO-ASA method and reveals that the subtle interplay between the local atomic environments and the bond energies determines the structural and site preferences for these systems.« less

  16. General review of multispectral cooled IR development at CEA-Leti, France

    NASA Astrophysics Data System (ADS)

    Boulard, F.; Marmonier, F.; Grangier, C.; Adelmini, L.; Gravrand, O.; Ballet, P.; Baudry, X.; Baylet, J.; Badano, G.; Espiau de Lamaestre, R.; Bisotto, S.

    2017-02-01

    Multicolor detection capabilities, which bring information on the thermal and chemical composition of the scene, are desirable for advanced infrared (IR) imaging systems. This communication reviews intra and multiband solutions developed at CEA-Leti, from dual-band molecular beam epitaxy grown Mercury Cadmium Telluride (MCT) photodiodes to plasmon-enhanced multicolor IR detectors and backside pixelated filters. Spectral responses, quantum efficiency and detector noise performances, pros and cons regarding global system are discussed in regards to technology maturity, pixel pitch reduction, and affordability. From MWIR-LWIR large band to intra MWIR or LWIR bands peaked detection, results underline the full possibility developed at CEA-Leti.

  17. Cluster-to-cluster transformation among Au6, Au8 and Au11 nanoclusters.

    PubMed

    Ren, Xiuqing; Fu, Junhong; Lin, Xinzhang; Fu, Xuemei; Yan, Jinghui; Wu, Ren'an; Liu, Chao; Huang, Jiahui

    2018-05-22

    We present the cluster-to-cluster transformations among three gold nanoclusters, [Au6(dppp)4]2+ (Au6), [Au8(dppp)4Cl2]2+ (Au8) and [Au11(dppp)5]3+ (Au11). The conversion process follows a rule that states that the transformation of a small cluster to a large cluster is achieved through an oxidation process with an oxidizing agent (H2O2) or with heating, while the conversion of a large cluster to a small one occurs through a reduction process with a reducing agent (NaBH4). All the reactions were monitored using UV-Vis spectroscopy and ESI-MS. This work may provide an alternative approach to the synthesis of novel gold nanoclusters and a further understanding of the structural transformation relationship of gold nanoclusters.

  18. Interfacial nanodroplets guided construction of hierarchical Au, Au-Pt, and Au-Pd particles as excellent catalysts

    NASA Astrophysics Data System (ADS)

    Ma, Aijing; Xu, Jie; Zhang, Xuehua; Zhang, Bin; Wang, Dayang; Xu, Haolan

    2014-05-01

    Interfacial nanodroplets were grafted to the surfaces of self-sacrificed template particles in a galvanic reaction system to assist the construction of 3D Au porous structures. The interfacial nanodroplets were formed via direct adsorption of surfactant-free emulsions onto the particle surfaces. The interfacial nanodroplets discretely distributed at the template particle surfaces and served as soft templates to guide the formation of porous Au structures. The self-variation of footprint sizes of interfacial nanodroplets during Au growth gave rise to a hierarchical pore size distribution of the obtained Au porous particles. This strategy could be easily extended to synthesize bimetal porous particles such as Au-Pt and Au-Pd. The obtained porous Au, Au-Pt, and Au-Pd particles showed excellent catalytic activity in catalytic reduction of 4-nitrophenol.

  19. [Sensitivity, specificity and prognostic value of CEA in colorectal cancer: results of a Tunisian series and literature review].

    PubMed

    Bel Hadj Hmida, Y; Tahri, N; Sellami, A; Yangui, N; Jlidi, R; Beyrouti, M I; Krichen, M S; Masmoudi, H

    2001-01-01

    In order to determine the sensitivity of CEA in the diagnosis of colo-rectal carcinoma, we studied a series of 48 patients with colo-rectal carcinoma (1992-1996). The sensitivity was at 52% with a reference value of 5 ng/ml and 68.7% for a reference value of 2.5 ng/ml. With a reference value of 5 ng/ml, the sensitivity of CEA was at 37% only for patients with colo-rectal carcinoma at Dukes B stage, 66.6% for patients at stage C and 75% for patients at stage D. The dosage of CEA was carried out with a sandwich immunoenzymatic technique in tube. There is no statistic significant correlation between the pre-operative rate of CEA and the localisation of the tumor and its histologic type; in contrast, it was significantly correlated with the ganglionnary metastasis. A significant relationship between the pre-operative rate of CEA and the Dukes stage was found for a reference value of 10 ng/ml but not for a reference value of 5 ng/ml. We calculated the specificity of the CEA for the cancers of colon and rectum which was at 76.98% with a reference value of 5 ng/ml and 86% with a reference value of 10 ng/ml.

  20. Novel flow cytometric analysis of the progress and route of internalization of a monoclonal anti-carcinoembryonic antigen (CEA) antibody.

    PubMed

    Ford, C H; Tsaltas, G C; Osborne, P A; Addetia, K

    1996-03-01

    A flow cytometric method of studying the internalization of a monoclonal antibody (Mab) directed against carcinoembryonic antigen (CEA) has been compared with Western blotting, using three human colonic cancer cell lines which express varying amounts of the target antigen. Cell samples incubated for increasing time intervals with fluoresceinated or unlabelled Mab were analyzed using flow cytometry or polyacrylamide gel electrophoresis and Western blotting. SDS/PAGE analysis of cytosolic and membrane components of solubilized cells from the cell lines provided evidence of non-degraded internalized anti-CEA Mab throughout seven half hour intervals, starting at 5 min. Internalized anti-CEA was detected in the case of high CEA expressing cell lines (LS174T, SKCO1). Very similar results were obtained with an anti-fluorescein flow cytometric assay. Given that these two methods consistently provided comparable results, use of flow cytometry for the detection of internalized antibody is suggested as a rapid alternative to most currently used methods for assessing antibody internalization. The question of the endocytic route followed by CEA-anti-CEA complexes was addressed by using hypertonic medium to block clathrin mediated endocytosis.

  1. Development and characterisation of MCT detectors for space astrophysics at CEA

    NASA Astrophysics Data System (ADS)

    Boulade, O.; Baier, N.; Castelein, P.; Cervera, C.; Chorier, P.; Destefanis, G.; Fièque, B.; Gravrand, O.; Guellec, F.; Moreau, V.; Mulet, P.; Pinsard, F.; Zanatta, J.-P.

    2017-11-01

    The Laboratoire Electronique et Traitement de l'Information (LETI) of the Commissariat à l'Energie Atomique (CEA, Grenoble, France) has been involved in the development of infrared detectors based on HgCdTe (MCT) material for over 30 years, mainly for defence and security programs [1]. Once the building blocks are developed at LETI (MCT material process, diode technology, hybridization, …), the industrialization is performed at SOFRADIR (also in Grenoble, France) which also has its own R&D program [2]. In past years, LETI also developed infrared detectors for space astrophysics in the mid infrared range - the long wave detector of the ISOCAM camera onboard ISO - as well as in the far infrared range - the bolometer arrays of the Herschel/PACS photometer unit -, both instruments which were under the responsibility of the Astrophysics department of CEA (IRFU/SAp, Saclay, France). Nowadays, the infrared detectors used in space and ground based astronomical instruments all come from vendors in the US. For programmatic reasons - increase the number of available vendors, decrease the cost, mitigate possible export regulations, …- as well as political ones - spend european money in Europe -, the European Space Agency (ESA) defined two roadmaps (one in the NIR-SWIR range, one in the MWIR-LWIR range) that will eventually allow for the procurement of infrared detectors for space astrophysics within Europe. The French Space Agency (CNES) also started the same sort of roadmaps, as part of its contribution to the different space missions which involve delivery of instruments by French laboratories. It is important to note that some of the developments foreseen in these roadmaps also apply to Earth Observations. One of the main goal of the ESA and CNES roadmaps is to reduce the level of dark current in MCT devices at all wavelengths. The objective is to use the detectors at the highest temperature where the noise induced by the dark current stays compatible with the photon

  2. DOE Office of Scientific and Technical Information (OSTI.GOV)

    None

    Plusieurs orateurs rendent hommage au grand physicien et scientifique Vladimir Jurko Glaser (1924 - 1984) qui travaillait au Ruder Boscovic Institut à Zagreb avant de venir au Cern en 1957 où il trouvait un poste permanent au département de physique théorique. Walter Tearing, Harry Lehmann,Henry Epstein, Jacques Bros et André Martin font des résumés biographiques de leurs collègue et ami en honorant ses grands qualités d'homme et ses remarquables conquêtes de la science et leurs accomplissement.

  3. Analgesic Effects of Duloxetine on Formalin-Induced Hyperalgesia and Its Underlying Mechanisms in the CeA

    PubMed Central

    Zhang, Lie; Yin, Jun-Bin; Hu, Wei; Zhao, Wen-Jun; Fan, Qing-Rong; Qiu, Zhi-Chun; He, Ming-Jie; Ding, Tan; Sun, Yan; Kaye, Alan D.; Wang, En-Ren

    2018-01-01

    In rodents, the amygdala has been proposed to serve as a key center for the nociceptive perception. Previous studies have shown that extracellular signal-regulated kinase (ERK) signaling cascade in the central nucleus of amygdala (CeA) played a functional role in inflammation-induced peripheral hypersensitivity. Duloxetine (DUL), a serotonin and noradrenaline reuptake inhibitor, produced analgesia on formalin-induced spontaneous pain behaviors. However, it is still unclear whether single DUL pretreatment influences formalin-induced hypersensitivity and what is the underlying mechanism. In the current study, we revealed that systemic pretreatment with DUL not only dose-dependently suppressed the spontaneous pain behaviors, but also relieved mechanical and thermal hypersensitivity induced by formalin hindpaw injection. Consistent with the analgesic effects of DUL on the pain behaviors, the expressions of Fos and pERK that were used to check the neuronal activities in the spinal cord and CeA were also dose-dependently reduced following DUL pretreatment. Meanwhile, no emotional aversive behaviors were observed at 24 h after formalin injection. The concentration of 5-HT in the CeA was correlated with the dose of DUL in a positive manner at 24 h after formalin injection. Direct injecting 5-HT into the CeA suppressed both the spontaneous pain behaviors and hyperalgesia induced by formalin injection. However, DUL did not have protective effects on the formalin-induced edema of hindpaw. In sum, the activation of CeA neurons may account for the transition from acute pain to long-term hyperalgesia after formalin injection. DUL may produce potent analgesic effects on the hyperalgesia and decrease the expressions of p-ERK through increasing the concentration of serotonin in the CeA. PMID:29692727

  4. Analgesic Effects of Duloxetine on Formalin-Induced Hyperalgesia and Its Underlying Mechanisms in the CeA.

    PubMed

    Zhang, Lie; Yin, Jun-Bin; Hu, Wei; Zhao, Wen-Jun; Fan, Qing-Rong; Qiu, Zhi-Chun; He, Ming-Jie; Ding, Tan; Sun, Yan; Kaye, Alan D; Wang, En-Ren

    2018-01-01

    In rodents, the amygdala has been proposed to serve as a key center for the nociceptive perception. Previous studies have shown that extracellular signal-regulated kinase (ERK) signaling cascade in the central nucleus of amygdala (CeA) played a functional role in inflammation-induced peripheral hypersensitivity. Duloxetine (DUL), a serotonin and noradrenaline reuptake inhibitor, produced analgesia on formalin-induced spontaneous pain behaviors. However, it is still unclear whether single DUL pretreatment influences formalin-induced hypersensitivity and what is the underlying mechanism. In the current study, we revealed that systemic pretreatment with DUL not only dose-dependently suppressed the spontaneous pain behaviors, but also relieved mechanical and thermal hypersensitivity induced by formalin hindpaw injection. Consistent with the analgesic effects of DUL on the pain behaviors, the expressions of Fos and pERK that were used to check the neuronal activities in the spinal cord and CeA were also dose-dependently reduced following DUL pretreatment. Meanwhile, no emotional aversive behaviors were observed at 24 h after formalin injection. The concentration of 5-HT in the CeA was correlated with the dose of DUL in a positive manner at 24 h after formalin injection. Direct injecting 5-HT into the CeA suppressed both the spontaneous pain behaviors and hyperalgesia induced by formalin injection. However, DUL did not have protective effects on the formalin-induced edema of hindpaw. In sum, the activation of CeA neurons may account for the transition from acute pain to long-term hyperalgesia after formalin injection. DUL may produce potent analgesic effects on the hyperalgesia and decrease the expressions of p-ERK through increasing the concentration of serotonin in the CeA.

  5. Gfr Core Neutronics Studies at CEA

    NASA Astrophysics Data System (ADS)

    Bosq, J. C.; Brun-Magaud, V.; Rimpault, G.; Tommasi, J.; Conti, A.; Garnier, J. C.

    2006-04-01

    The Gas cooled Fast Reactor (GFR) is a high priority in the CEA R&D program on Future Nuclear Energy Systems. After preliminary neutronics and thermo-aerolic studies, a first He-cooled 2400MWth core design based on a series of carbide CERCER plates arranged in an hexagonal wrapper were selected. Although GFR subassembly and core design studies are still at an early stage of development, it is nonetheless possible to identify a number of nuclear data needs that could have some impact on the actual design: new materials, decay heat contributors….

  6. Suppression of Υ production in d + Au + and Au + Au collisions at √ sNN =200 GeV

    DOE PAGES

    None

    2014-07-01

    We report measurements of Upsilon meson production in p + p, d +Au, and Au+Au collisions using the STAR detector at RHIC. We compare the Upsilon yield to the measured cross section in p + p collisions in order to quantify any modifications of the yield in cold nuclear matter using d +Au data and in hot nuclear matter using Au+Au data separated into three centrality classes. Our p +p measurement is based on three times the statistics of our previous result. We obtain a nuclear modification factor for Upsilon (1S + 2S + 3S) in the rapidity range |y|more » < 1 in d + Au collisions of R dAu = 0.79 ± 0.24(stat.) ± 0.03(syst.) ± 0.10(p + p syst.). A comparison with models including shadowing and initial state part on energy loss indicates the presence of additional cold-nuclear matter suppression. Similarly, in the top 10% most-central Au + Au collisions, we measure a nuclear modification factor of R AA = 0.49 ±0.1(stat.) ±0.02(syst.) ±0.06(p + p syst.), which is a larger suppression factor than that seen in cold nuclear matter. Our results are consistent with complete suppression of excited-state Upsilon mesons in Au + Au collisions. The additional suppression in Au + Au is consistent with the level expected in model calculations that include the presence of a hot, deconfined Quark–Gluon Plasma. However, understanding the suppression seen in d + Au is still needed before any definitive statements about the nature of the suppression in Au + Au can be made.« less

  7. Simplifying CEA through Excel, VBA, and Subeq

    NASA Technical Reports Server (NTRS)

    Foster, Ryan

    2004-01-01

    Many people use compound equilibrium programs for very different reasons, varying from refrigerators to light bulbs to rockets. A commonly used equilibrium program is CEA. CEA can take various inputs such as pressure, temperature, and volume along with numerous reactants and run them through equilibrium equations to obtain valuable output information, including products formed and their relative amounts. A little over a year ago, Bonnie McBride created the program subeq with the goal to simplify the calling of CEA. Subeq was also designed to be called by other programs, including Excel, through the use of Visual Basic for Applications (VBA). The largest advantage of using Excel is that it allows the user to input the information in a colorful and user-friendly environment while allowing VBA to run subeq, which is in the form of a FORTRAN DLL (Dynamic Link Library). Calling subeq in this form makes it much faster than if it were converted to VBA. Since subeq requires such large lists of reactant and product names, all of which can't be passed in as an array, subeq had to be changed to accept very long strings of reactants and products. To pass this string and adjust the transfer of input and output parameters, the subeq DLL had to be changed. One program that does this is Compaq Visual FORTRAN, which allows DLLs to be edited, debugged, and compiled. Compaq Visual FORTRAN uses FORTRAN 90/95, which has additional features to that of FORTRAN 77. My goals this summer include finishing up the excel spreadsheet of subeq, which I started last summer, and putting it on the Internet so that others can use it without having to download my spreadsheet. To finish up the spreadsheet I will need to work on debugging current options and problems. I will also work on making it as robust as possible, so that all errors that may arise will be clearly communicated to the user. New features will be added old ones will be changed as I receive comments from people using the spreadsheet

  8. Chiral magnetic effect search in p+Au, d+Au and Au+Au collisions at RHIC

    NASA Astrophysics Data System (ADS)

    Zhao, Jie

    2018-01-01

    Metastable domains of fluctuating topological charges can change the chirality of quarks and induce local parity violation in quantum chromodynamics. This can lead to observable charge separation along the direction of the strong magnetic field produced by spectator protons in relativistic heavy-ion collisions, a phenomenon called the chiral magnetic effect (CME). A major background source for CME measurements using the charge-dependent azimuthal correlator (Δϒ) is the intrinsic particle correlations (such as resonance decays) coupled with the azimuthal elliptical anisotropy (v2). In heavy-ion collisions, the magnetic field direction and event plane angle are correlated, thus the CME and the v2-induced background are entangled. In this report, we present two studies from STAR to shed further lights on the background issue. (1) The Δϒ should be all background in small system p+Au and d+Au collisions, because the event plane angles are dominated by geometry fluctuations uncorrelated to the magnetic field direction. However, significant Δϒ is observed, comparable to the peripheral Au+Au data, suggesting a background dominance in the latter, and likely also in the mid-central Au+Au collisions where the multiplicity and v2 scaled correlator is similar. (2) A new approach is devised to study Δϒ as a function of the particle pair invariant mass (minv) to identify the resonance backgrounds and hence to extract the possible CME signal. Signal is consistent with zero within uncertainties at high minv. Signal at low minv, extracted from a two-component model assuming smooth mass dependence, is consistent with zero within uncertainties.

  9. Comparison of the CEAS and Williams-type barley yield models for North Dakota and Minnesota

    NASA Technical Reports Server (NTRS)

    Leduc, S. (Principal Investigator)

    1982-01-01

    The CEAS and Williams type models were compared based on specified selection criteria which includes a ten year bootstrap test (1970-1979). Based on this, the models were quite comparable; however, the CEAS model was slightly better overall. The Williams type model seemed better for the 1974 estimates. Because that year spring wheat yield was particularly low, the Williams type model should not be excluded from further consideration.

  10. Dexamethasone minimizes the risk of cranial nerve injury during CEA.

    PubMed

    Regina, Guido; Angiletta, Domenico; Impedovo, Giovanni; De Robertis, Giovanni; Fiorella, Marialuisa; Carratu', Maria Rosaria

    2009-01-01

    The incidence of cranial and cervical nerve injury during carotid endarterectomy (CEA) ranges from less than 7.6% to more than 50%. Lesions are mainly due to surgical maneuvers such as traction, compression, tissue electrocoagulation, clamping, and extensive dissections. The use of dexamethasone (DEX) and its beneficial effects in spinal cord injuries have already been described. We investigated whether DEX could also be beneficial to minimize the incidence of cranial and cervical nerve injury during CEA. To evaluate whether dexamethasone is able to reduce the incidence of cranial nerve injuries. From March 1999 through April 2006, 1126 patients undergoing CEA because of high-grade carotid stenosis were enrolled and randomized by predetermined randomization tables into two groups. The first group, "A", included 586 patients that all received an intravenous administration of dexamethasone following a therapeutic scheme. The second group, "B", included 540 control subjects that received the standard pre- and postoperative therapy. All patients were submitted to a deep cervical plexus block, eversion carotid endarterectomy, and selective shunting. Three days after the operation, an independent neurologist and otorhinolaryngologist evaluated the presence of cranial nerve deficits. All patients (group A and group B) showing nerve injuries continued the treatment (8 mg of dexamethasone once in the morning) for 7 days and were re-evaluated after 2 weeks, 30 days, and every 3 months for 1 year. Recovery time took from 2 weeks to 12 months, with a mean time of 3.6 months. The chi(2) test was used to compare the two groups and to check for statistical significance. The incidence of cranial nerve dysfunction was higher in group B and the statistical analysis showed a significant effect of dexamethasone in preventing the neurological damage (P = .0081). The incidence of temporary lesions was lower in group A and the chi(2) test yielded a P value of .006. No statistically

  11. Successful synthesis and thermal stability of immiscible metal Au-Rh, Au-Ir andAu-Ir-Rh nanoalloys

    NASA Astrophysics Data System (ADS)

    Shubin, Yury; Plyusnin, Pavel; Sharafutdinov, Marat; Makotchenko, Evgenia; Korenev, Sergey

    2017-05-01

    We successfully prepared face-centred cubic nanoalloys in systems of Au-Ir, Au-Rh and Au-Ir-Rh, with large bulk miscibility gaps, in one-run reactions under thermal decomposition of specially synthesised single-source precursors, namely, [AuEn2][Ir(NO2)6], [AuEn2][Ir(NO2)6] х [Rh(NO2)6]1-х and [AuEn2][Rh(NO2)6]. The precursors employed contain all desired metals ‘mixed’ at the atomic level, thus providing significant advantages for obtaining alloys. The observations using high-resolution transmission electron microscopy show that the nanoalloy structures are composed of well-dispersed aggregates of crystalline domains with a mean size of 5 ± 3 nm. Еnergy dispersive x-ray spectroscopy and x-ray powder diffraction (XRD) measurements confirm the formation of AuIr, AuRh, AuIr0.75Rh0.25, AuIr0.50Rh0.50 and AuIr0.25Rh0.75 metastable solid solutions. In situ high-temperature synchrotron XRD (HTXRD) was used to study the formation mechanism of nanoalloys. The observed transformations are described by the ‘conversion chemistry’ mechanism characterised by the primary development of particles comprising atoms of only one type, followed by a chemical reaction resulting in the final formation of a nanoalloy. The obtained metastable nanoalloys exhibit essential thermal stability. Exposure to 180 °C for 30 h does not cause any dealloying process.

  12. Successful synthesis and thermal stability of immiscible metal Au-Rh, Au-Ir andAu-Ir-Rh nanoalloys.

    PubMed

    Shubin, Yury; Plyusnin, Pavel; Sharafutdinov, Marat; Makotchenko, Evgenia; Korenev, Sergey

    2017-05-19

    We successfully prepared face-centred cubic nanoalloys in systems of Au-Ir, Au-Rh and Au-Ir-Rh, with large bulk miscibility gaps, in one-run reactions under thermal decomposition of specially synthesised single-source precursors, namely, [AuEn 2 ][Ir(NO 2 ) 6 ], [AuEn 2 ][Ir(NO 2 ) 6 ] х [Rh(NO 2 ) 6 ] 1-х and [AuEn 2 ][Rh(NO 2 ) 6 ]. The precursors employed contain all desired metals 'mixed' at the atomic level, thus providing significant advantages for obtaining alloys. The observations using high-resolution transmission electron microscopy show that the nanoalloy structures are composed of well-dispersed aggregates of crystalline domains with a mean size of 5 ± 3 nm. Еnergy dispersive x-ray spectroscopy and x-ray powder diffraction (XRD) measurements confirm the formation of AuIr, AuRh, AuIr 0.75 Rh 0.25 , AuIr 0.50 Rh 0.50 and AuIr 0.25 Rh 0.75 metastable solid solutions. In situ high-temperature synchrotron XRD (HTXRD) was used to study the formation mechanism of nanoalloys. The observed transformations are described by the 'conversion chemistry' mechanism characterised by the primary development of particles comprising atoms of only one type, followed by a chemical reaction resulting in the final formation of a nanoalloy. The obtained metastable nanoalloys exhibit essential thermal stability. Exposure to 180 °C for 30 h does not cause any dealloying process.

  13. Environmental Profiles of Paper vs. Electronic UC-CEAS Annual Reports

    EPA Science Inventory

    In 2010, the University of Cincinnati College of Engineering and Applied Sciences (UC-CEAS) created a new electronic format for the Annual Report that could be distributed through the college’s website to replace the prior print version. In order to determine the environmental co...

  14. Memorial V.J.Glaser

    ScienceCinema

    None

    2017-12-09

    Plusieurs orateurs rendent hommage au grand physicien et scientifique Vladimir Jurko Glaser (1924 - 1984) qui travaillait au Ruder Boscovic Institut à Zagreb avant de venir au Cern en 1957 où il trouvait un poste permanent au département de physique théorique. Walter Tearing, Harry Lehmann,Henry Epstein, Jacques Bros et André Martin font des résumés biographiques de leurs collègue et ami en honorant ses grands qualités d'homme et ses remarquables conquêtes de la science et leurs accomplissement.

  15. Au38(SPh)24: Au38 Protected with Aromatic Thiolate Ligands.

    PubMed

    Rambukwella, Milan; Burrage, Shayna; Neubrander, Marie; Baseggio, Oscar; Aprà, Edoardo; Stener, Mauro; Fortunelli, Alessandro; Dass, Amala

    2017-04-06

    Au 38 (SR) 24 is one of the most extensively investigated gold nanomolecules along with Au 25 (SR) 18 and Au 144 (SR) 60 . However, so far it has only been prepared using aliphatic-like ligands, where R = -SC 6 H 13 , -SC 12 H 25 and -SCH 2 CH 2 Ph. Au 38 (SCH 2 CH 2 Ph) 24 when reacted with HSPh undergoes core-size conversion to Au 36 (SPh) 24 , and existing literature suggests that Au 38 (SPh) 24 cannot be synthesized. Here, contrary to prevailing knowledge, we demonstrate that Au 38 (SPh) 24 can be prepared if the ligand exchanged conditions are optimized, under delicate conditions, without any formation of Au 36 (SPh) 24 . Conclusive evidence is presented in the form of matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), electrospray ionization mass spectra (ESI-MS) characterization, and optical spectra of Au 38 (SPh) 24 in a solid glass form showing distinct differences from that of Au 38 (S-aliphatic) 24 . Theoretical analysis confirms experimental assignment of the optical spectrum and shows that the stability of Au 38 (SPh) 24 is not negligible with respect to that of its aliphatic analogous, and contains a significant component of ligand-ligand attractive interactions. Thus, while Au 38 (SPh) 24 is stable at RT, it converts to Au 36 (SPh) 24 either on prolonged etching (longer than 2 hours) at RT or when etched at 80 °C.

  16. An Information Building on Radioactivity and Nuclear Energy for the French CEA Cadarache Research Center - 13492

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Brunel, Guy; Denis, Dominique; Boulet, Alain

    The CEA Cadarache research center is one of the 10 research centers of the French Alternative Energies and Atomic Energy Commission (CEA). Distributed throughout various research platforms, it focuses on nuclear fission, nuclear fusion, new energy technologies (hydrogen, solar, biomass) and fundamental research in the field of vegetal biology. It is the most important technological research and development centers for energy in Europe. Considering the sensitive nature of nuclear activities, the questions surrounding the issue of radioactive waste, the nuclear energy and the social, economic and environmental concerns for present and future generations, the French Government asked nuclear actors tomore » open communication and to give all the information asked by the Local Information Commission (CLI) and the public [1]. In this context, the CEA Cadarache has decided to better show and explain its expertise and experience in the area of nuclear energy and nuclear power plant design, and to make it available to stakeholders and to the public. CEA Cadarache receives each year more than 9000 visitors. To complete technical visits of the research facilities and laboratories, a scientific cultural center has been built in 2011 to inform the public on CEA Cadarache research activities and to facilitate the acceptance of nuclear energy in a way suited to the level of knowledge of the visitors. A modern interactive exhibition of 150 m{sup 2} allows visitors to find out more about energy, CEA Cadarache research programs, radioactive waste management and radiological impact on the research center activities. It also offers an auditorium for group discussions and for school groups to discover science through enjoyment. This communication center has received several thousand visitors since its opening on October 2011; the initial results of this experience are now available. It's possible to explain the design of this exhibition, to give some statistics on the number of the

  17. Evidence of final-state suppression of high-p{_ T} hadrons in Au + Au collisions using d + Au measurements at RHIC

    NASA Astrophysics Data System (ADS)

    Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Becker, B.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Harrington, A. S.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Lee, J. W.; Lin, W. T.; Manly, S.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Roland, C.; Roland, G.; Sagerer, J.; Sarin, P.; Sedykh, I.; Skulski, W.; Smith, C. E.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Veres, G. I.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wysłouch, B.; Zhang, J.

    Transverse momentum spectra of charged hadrons with pT < 6 GeV/c have been measured near mid-rapidity (0.2 < ɛ < 1.4) by the PHOBOS experiment at RHIC in Au + Au and d + Au collisions at {√ {s{NN}} = {200 GeV}}. The spectra for different collision centralities are compared to {p + ¯ {p}} collisions at the same energy. The resulting nuclear modification factor for central Au + Au collisions shows evidence of strong suppression of charged hadrons in the high-pT region (>2 GeV/c). In contrast, the d + Au nuclear modification factor exhibits no suppression of the high-pT yields. These measurements suggest a large energy loss of the high-pT particles in the highly interacting medium created in the central Au + Au collisions. The lack of suppression in d + Au collisions suggests that it is unlikely that initial state effects can explain the suppression in the central Au + Au collisions. PACS: 25.75.-q

  18. 3D morphology of Au and Au@Ag nanobipyramids

    NASA Astrophysics Data System (ADS)

    Burgin, Julien; Florea, Ileana; Majimel, Jérôme; Dobri, Adam; Ersen, Ovidiu; Tréguer-Delapierre, Mona

    2012-02-01

    The morphologies of Au and Au@Ag nanobipyramids were investigated using electron tomography. The 3D reconstruction reveals that the Au bipyramids have an irregular six-fold twinning structure with highly stepped dominant {151} facets. These short steps/edges stabilized via surface adsorbed CTAB favor the growth of silver on the lateral facets leading to strong blue shifts in longitudinal plasmon surface resonance.The morphologies of Au and Au@Ag nanobipyramids were investigated using electron tomography. The 3D reconstruction reveals that the Au bipyramids have an irregular six-fold twinning structure with highly stepped dominant {151} facets. These short steps/edges stabilized via surface adsorbed CTAB favor the growth of silver on the lateral facets leading to strong blue shifts in longitudinal plasmon surface resonance. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr11454b

  19. [Clinical value of combined detection of LDH, TPS, CEA and beta2-MG in patients with non- Hodgkin's lymphoma].

    PubMed

    Chen, Wei; Luo, Rong-cheng; Fan, Wei-wen; Ma, Shu-dong

    2006-02-01

    To study the clinical value of combined detection of 4 tumor markers, namely lactic dehydrogenate (LDH), tissue polypeptide specific antigen (TPS), carcinoembryonic antigen (CEA) and beta2-microglobulin (beta2-MG) in patients with non-Hodgkin's lymphoma (NHL). The serum level of LDH was determined with automatic biochemical analyzer and TPS, CEA and beta2-MG levels were determined by enzyme-linked immumosorbent assay (ELISA) in 59 patients with NHL and 40 healthy adults. The levels of the 4 tumor markers were significantly higher in NHL patients than in the healthy control subjects (P<0.05). After chemotherapy, the serum levels of TPS and beta2-MG were significantly lowered in the patients who showed favorable response to the treatment (P<0.05), but the levels of LDH and CEA showed no significant change (P>0.05). The serum levels of LDH, TPS, CEA and beta2-MG in the patients in a stable or progressive phase did had no significant changes after chemotherapy (P>0.05). Combined detection of LDH, TPS, CEA and beta2-MG can be helpful to assist diagnosis of NHL and treatment evaluation.

  20. Ex vivo PD-L1/PD-1 pathway blockade reverses dysfunction of circulating CEA specific T cells in pancreatic cancer patients

    PubMed Central

    Chen, Y; Xue, SA; Behboudi, S; Mohammad, GH; Pereira, SP; Morris, EC

    2017-01-01

    Carcinoembryonic antigen (CEA) is a candidate target for cellular immunotherapy of pancreatic cancer (PC). In this study, we have characterised the antigen-specific function of autologous cytotoxic T lymphocytes (CTL) specific for the HLA-A2 restricted peptide, pCEA691–699, isolated from the peripheral T cell repertoire of PC patients and sought to determine if ex vivo PD-L1 & TIM3 blockade could enhance CTL function. CD8+ T cell lines were generated from peripheral blood mononuclear cells (PBMCs) of 18 HLA-A2+ patients with PC and from 15 healthy controls. In vitro peptide specific responses were evaluated by flow cytometry after staining for intracellular cytokine production and CSFE cytotoxicity assays using pancreatic cancer cell lines as targets. Cytokine secreting functional CEA691-specific CTL lines were successfully generated from 10 of 18PC patients, with two CTL lines able to recognise and kill both CEA691 peptide-loaded T2 cells and CEA+ HLA-A2+ pancreatic cancer cell lines. In the presence of ex vivo PD-L1 blockade, functional CEA691-specific CD8+ T cell responses, including IFN-γ secretion and proliferation, were enhanced and this effect was more pronounced on Ag-specific T cells isolated from tumor draining lymph nodes. These data demonstrate that CEA691-specific CTL can be readily expanded from the self-restricted T cell repertoire of PC patients and that their function can be enhanced by PD-L1 blockade. PMID:28710313

  1. Aeroacoustics research in Europe: The CEAS-ASC report on 2013 highlights

    NASA Astrophysics Data System (ADS)

    Bennett, G. J.; Kennedy, J.; Meskell, C.; Carley, M.; Jordan, P.; Rice, H.

    2015-03-01

    The Council of European Aerospace Societies (CEAS) Aeroacoustics Specialists Committee (ASC) supports and promotes the interests of the scientific and industrial aeroacoustics community on an European scale and European aeronautics activities internationally. In this context, "aeroacoustics" encompasses all aerospace acoustics and related areas. Each year the committee highlights some of the research and development projects in Europe. This paper is a report on highlights of aeroacoustics research in Europe in 2013, compiled from information provided to the ASC of the CEAS. During 2013, a number of research programmes involving aeroacoustics were funded by the European Commission. Some of the highlights from these programmes are summarised in this paper, as well as highlights from other programmes funded by national programmes or by industry. Furthermore, a concise summary of the CEAS-ASC workshop "Atmospheric and Ground Effects on Aircraft Noise" held in Seville, Spain in September 2013 is included in this report. Enquiries concerning all contributions should be addressed to the authors who are given at the end of each subsection. This issue of the "highlights" paper is dedicated to the memory of Prof. John A. Fitzpatrick, Professor of Mechanical Engineering, Trinity College Dublin, and a valued member of the Aeroacoustics Specialists Committee. John passed away in September 2012 and is fondly missed across the globe by the friends he made in the Aeroacoustics Community. This paper is edited by PhD graduates and colleagues of John's who conduct research in aeroacoustics, inspired by his thirst for knowledge.

  2. Aeroacoustics research in Europe: The CEAS-ASC report on 2012 highlights

    NASA Astrophysics Data System (ADS)

    Bodén, H.; Efraimsson, G.

    2013-12-01

    The Council of European Aerospace Societies (CEAS) Aeroacoustics Specialists Committee (ASC) supports and promotes the interests of the scientific and industrial aeroacoustics community on an European scale and European aeronautics activities internationally. In this context, "aeroacoustics" encompasses all aerospace acoustics and related areas. Each year the committee highlights some of the research and development projects in Europe. This paper is a report on highlights of aeroacoustics research in Europe in 2012, compiled from information provided to the ASC of the CEAS. During 2012, a number of research programmes involving aeroacoustics were funded by the European Commission. Some of the highlights from these programmes are summarized in this paper, as well as highlights from other programmes funded by national programmes or by industry. Enquiries concerning all contributions should be addressed to the authors who are given at the end of each subsection.

  3. Thymidine kinase 1 combined with CEA, CYFRA21-1 and NSE improved its diagnostic value for lung cancer.

    PubMed

    Jiang, Z F; Wang, M; Xu, J L

    2018-02-01

    Thymidine kinase 1 (TK1) is a tumor biomarker in human malignancies. The purpose of this study was to evaluate the diagnostic efficiency of this marker for lung cancer using the combined analysis of carcinoembryonic antigen (CEA), cytokeratin-19 fragment (CYFRA21-1), neuron specific enolase (NSE) and TK1. From 2013 to 2014, 147 patients with lung cancer and 228 patients with lung benign diseases who were admitted to our hospital were reviewed. Peripheral blood samples were collected for the detection of TK1, CEA, CYFRA21-1 and NSE. The diagnostic value of each marker was analyzed using receiver operating characteristic (ROC) curves and logistic regression equations. The serum levels of TK1, CEA, CYFRA21-1 and NSE were significantly higher than those in patients with lung benign diseases (all P<0.05). The TK1 concentration was dependent on TNM stage (P=0.005). The ROC curve analyses showed that the diagnostic value of TK1 combined with CEA, CYFRA21-1 and NSE in lung cancer was significantly higher than that of each biomarker alone (all P<0.0001). In addition, TK1 combined with CEA, CYFRA21-1, or NSE could also improve the diagnosis of the squamous cell carcinoma, adenocarcinoma and small cell lung cancer subtypes, respectively. The combined detection of TK1 and the other three markers significantly improved the diagnosis of lung cancer. Furthermore, the detection of TK1 combined with that of CYFRA21-1, CEA or NSE increased the diagnostic value of TK1 for lung squamous cell carcinoma, adenocarcinoma and SCLC, respectively. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Efficient induction of anti-tumor immunity by a TAT-CEA fusion protein vaccine with poly(I:C) in a murine colorectal tumor model.

    PubMed

    Park, Jung-Sun; Kim, Hye-Sung; Park, Hye-Mi; Kim, Chang-Hyun; Kim, Tai-Gyu

    2011-11-03

    Protein vaccines may be a useful strategy for cancer immunotherapy because recombinant tumor antigen proteins can be produced on a large scale at relatively low cost and have been shown to be safe for clinical application. However, protein vaccines have historically exhibited poor immunogenicity; thus, an improved strategy is needed for successful induction of immune responses. TAT peptide is a protein transduction domain composed of an 11-amino acid peptide (TAT(47-57): YGRKKRRQRRR). The positive charge of this peptide allows protein antigen fused with it to improve cell penetration. Poly(I:C) is a synthetic double-stranded RNA that is negatively charged and favors interaction with the cationic TAT peptide. Poly(I:C) has been reported on adjuvant role in tumor vaccine through promotion of immune responses. Therefore, we demonstrated that vaccine with a mixture of TAT-CEA fusion protein and poly(I:C) can induce anti-tumor immunity in a murine colorectal tumor model. Splenocytes from mice vaccinated with a mixture of TAT-CEA fusion protein and poly(I:C) effectively induced CEA-specific IFN-γ-producing T cells and showed cytotoxic activity specific for MC-38-cea2 tumor cells expressing CEA. Vaccine with a mixture of TAT-CEA fusion protein and poly(I:C) delayed tumor growth in MC-38-cea-2 tumor-bearing mice. Depletion of CD8(+) T cells and NK cells reversed the inhibition of tumor growth in an MC-38-cea2-bearing mice, indicating that CD8(+) T cells and NK cells are responsible for anti-tumor immunity by vaccine with a mixture of TAT-CEA fusion protein and poly(I:C). Taken together, these results suggest that poly(I:C) could be used as a potent adjuvant to induce the anti-tumor immunity of a TAT-CEA fusion protein vaccine in a murine colorectal tumor model. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Deterministic Role of CEA and MSI Status in Predicting Outcome of CRC Patients: a Perspective Study Amongst Hospital Attending Eastern Indian Populations.

    PubMed

    Koyel, Banerjee; Priyabrata, Das; Rittwika, Bhattacharya; Swati, Dasgupta; Soma, Mukhopadhyay; Jayasri, Basak; Ashis, Mukhopadhyay

    2017-12-01

    Carcinoembryonic antigen (CEA) is an important deterministic factor in predicting colorectal carcinoma (CRC) progression. It is also evident that microsatellite instability (MSI) which results in a hypermutable phenotype of genomic DNA is common in CRC. Owing to the scarcity of reports from India, our aim of this study was to understand the clinicopathological correlations of CEA status with surgery and chemotherapy, correlate the same with socio-demographic status of the patients, determine the MSI status amongst them and understand the prognostic implications of CEA and MSI as CRC progression marker amongst patients. The serum CEA level was estimated by chemiluminescence assay (CLIA). Serum liver enzyme assay was carried out following the manufacturer's instructions using auto-analysers (E. Merck and Sera mol. Health Care, India). MSI analysis was carried out by PCR-SSCP. From our study, most frequently detected colorectal cancer was in 40-49 years age group (25.26%) with 61.05% male and 38.95% females. CEA showed a significant association with higher TNM staging, tumour size, smoking habit and MSI status ( p  < 0.05) but not with sex and site of cancer ( p  > 0.05). After surgery and chemotherapy, CEA and WBCs were decreased significantly ( p  < 0.05), while liver enzymes did not change significantly ( p  > 0.05). Overall, microsatellite instability was observed in approximately 40% of the populations. From our study, it was also evident that for both, MSI and abnormal CEA level predicted poor prognosis for the patient (by using Kaplan-Meier survival analysis; p  = 0.04). Thus, CEA and initial MSI status can be used as prognostic markers of CRC.

  6. [Usefulness of evaluation of carcinoembryonic antigen (CEA) and soluble fragments of cytokeratin 18-th (TPS) in postoperative monitoring of patients with colorectal cancer].

    PubMed

    Sandelewski, Artur; Kokocińska, Danuta; Partyka, Robert; Kocot, Jacek; Starzewski, Jacek; Chanek, Izabela; Jałowiecki, Przemysław

    2005-06-01

    The aim of this study is to diagnose the evaluation of concentration of CEA and TPS in postoperative monitoring of patients with colorectal cancer. We measured 178 consecutive patients with histopathologically confirmed colorectal cancer: 101 men and 78 women ages 22-86 (average age 54.7). Markers' CEA nad TPS concentration were evaluated before operation and every month after operation during the first 3 months and then every 3 months during 2 years. Relapse was detected in 47 patients. In postoperative period in non-relapse group the mean (the average) concentration of CEA was 1.92+/-2.03 ng/ml and TPS 65.54+/-33.96 U/l and respectively in relapse group for CEA was 1.92+/-2.03 ng/ml and for TPS 65.54+/-33.96 U/l. The obtained results in investigated group show significantly statistical. The relapse was confirmed by using CEA concentration in 42 patients (89.4%). In case of TPS concentration relapse was confirmed in 38 patients (80.85%). The relapse was detected in 45 patients (95.74) if increase in CEA or TPS concentration was treated as a way of detecting relapse. TPS markers point out that the increase of TPS concentartion may be ahead of relapse symptoms at about 2-6 months. TPS is a useful marker in postoperative monitoring of patients with colorectal cancer. The evaluation of TPS concentration allow to diagnose the recurrence of colorectal cancer earlier than by using burden markers--CEA. Common evaluation of TPS and CEA increase sensitivity in detection of relapse in patients with colorectal cancer.

  7. C.-E.A. Winslow Day: Proceedings of the June 3, 1977 Centenary Celebration

    PubMed Central

    Viseltear, Arthur J.

    1977-01-01

    Sponsored by Yale University, the City of New Haven, and the John B. Pierce Foundation, the C.-E.A. Winslow Day program consisted of speeches by Mr. Leonard Woodcock, President Emeritus, U.A.W., the Honorable Kenneth Gibson, Mayor of Newark, and Dr. Hector Acuña, Director, Pan American Health Organization; reminiscences of Ira Hiscock, Anna M.R. Lauder Professor Emeritus of Public Health, Mary Elizabeth Tennant, Associate Professor Emeritus of Nursing (Public Health), A. Pharo Gagge, Emeritus Fellow, John B. Pierce Foundation, and Mrs. Harriet Welch, Former President of the VNA of New Haven. The proceedings also included the presentation of gifts and the official C.-E.A. Winslow Day Proclamation. PMID:345631

  8. Combination of preoperative NLR, PLR and CEA could increase the diagnostic efficacy for I-III stage CRC.

    PubMed

    Peng, Hong-Xin; Yang, Lin; He, Bang-Shun; Pan, Yu-Qin; Ying, Hou-Qun; Sun, Hui-Ling; Lin, Kang; Hu, Xiu-Xiu; Xu, Tao; Wang, Shu-Kui

    2017-09-01

    Inflammation plays an important role in the development and progression of CRC. The members of inflammatory biomarkers, preoperative NLR and PLR, have been proved by numerous studies to be promising prognostic biomarkers for CRC. However, the diagnostic value of the two biomarkers in CRC remains unknown, and no study reported the combined diagnostic efficacy of NLR, PLR and CEA. Five hundred and fifty-nine patients with I-III stage CRC undergoing surgical resection and 559 gender- and age-matched healthy controls were enrolled in this retrospective study. NLR and PLR were calculated from preoperative peripheral blood cell count detected using white blood cell five classification by Sysmex XT-1800i Automated Hematology System and serum CEA were measured by electrochemiluminescence by ELECSYS 2010. The diagnostic performance of NLR, PLR and CEA for CRC was evaluated by ROC curve. Levels of NLR and PLR in the cases were significantly higher than them in the healthy controls. ROC curves comparison analyses showed that the diagnostic efficacy of NLR (AUC=.755, 95%CI=.728-.780) alone for CRC was significantly higher than PLR (AUC=.723, 95%CI=.696-.749, P=.037) and CEA (AUC=.690, 95%CI=.662-.717, P=.002) alone. In addition, the diagnostic efficacy of the combination of NLR, PLR and CEA(AUC=.831, 95%CI=.807-.852)for CRC was not only significantly higher than NLR alone but also higher than any combinations of the two of these three biomarkers (P<.05). Moreover, the NLR and PLR in the patients with TNM stage I/II was higher than that in the healthy controls, and patients with stage III had a higher NLR and PLR than those with stage I/II, but no significant difference was observed. Our study indicated that preoperative NLR could be a CRC diagnostic biomarker, even for early stage CRC, and the combination of NLR, PLR and CEA could significantly improve the diagnostic efficacy. © 2016 Wiley Periodicals, Inc.

  9. [A case of brain metastasis discovered after surgery for lung cancer based on changes in CEA, in which long-term survival was obtained by repeated gammaknife irradiation].

    PubMed

    Kakeya, Hiroshi; Inoue, Yuichi; Sawai, Toyomitsu; Ikuta, Yasushi; Ohno, Hideaki; Yanagihara, Katsunori; Higashiyama, Yasuhito; Miyazaki, Yoshitsugu; Soda, Hiroshi; Tashiro, Takayoshi; Kohno, Shigeru

    2005-12-01

    A 58-year-old man underwent right lower lobectomy for lung adenocarcinoma in June 1998. Since a high level of tumor marker CEA persisted after surgery, chemotherapy was additionally performed, and the CEA level subsequently normalized. However, the CEA level increased in April 1999, and brain metastasis was found in the left occipital lobe, and the first gammaknife irradiation was performed. Multiple brain metastases were found when CEA increased again in August 1999, and the second gammaknife irradiation was performed. Moreover, brain metastases were found in the left frontal and occipital lobes in February 2000, and the third gammaknife irradiation was performed. CEA normalized thereafter, but increased in February 2001. Brain metastasis was found in the right occipital lobe, and the fourth gammaknife irradiation was performed. CEA has remained within the normal range for about 4 years thereafter. Long-term survival was possible by repeated gammaknife irradiation for brain metastases. Monitoring of CEA played an important role in finding recurrent brain metastasis in this patient.

  10. Comparison of CEAS and Williams-type models for spring wheat yields in North Dakota and Minnesota

    NASA Technical Reports Server (NTRS)

    Barnett, T. L. (Principal Investigator)

    1982-01-01

    The CEAS and Williams-type yield models are both based on multiple regression analysis of historical time series data at CRD level. The CEAS model develops a separate relation for each CRD; the Williams-type model pools CRD data to regional level (groups of similar CRDs). Basic variables considered in the analyses are USDA yield, monthly mean temperature, monthly precipitation, and variables derived from these. The Williams-type model also used soil texture and topographic information. Technological trend is represented in both by piecewise linear functions of year. Indicators of yield reliability obtained from a ten-year bootstrap test of each model (1970-1979) demonstrate that the models are very similar in performance in all respects. Both models are about equally objective, adequate, timely, simple, and inexpensive. Both consider scientific knowledge on a broad scale but not in detail. Neither provides a good current measure of modeled yield reliability. The CEAS model is considered very slightly preferable for AgRISTARS applications.

  11. Evolution of Excited-State Dynamics in Periodic Au 28, Au 36, Au 44, and Au 52 Nanoclusters

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhou, Meng; Zeng, Chenjie; Sfeir, Matthew Y.

    An understanding of the correlation between the atomic structure and optical properties of gold nanoclusters is essential for exploration of their functionalities and applications involving light harvesting and electron transfer. We report the femto-nanosecond excited state dynamics of a periodic series of face-centered cubic (FCC) gold nanoclusters (including Au 28, Au 36, Au 44, and Au 52), which exhibit a set of unique features compared with other similar sized clusters. Molecular-like ultrafast S n → S 1 internal conversions (i.e., radiationless electronic transitions) are observed in the relaxation dynamics of FCC periodic series. Excited-state dynamics with near-HOMO–LUMO gap excitation lacksmore » ultrafast decay component, and only the structural relaxation dominates in the dynamical process, which proves the absence of core–shell relaxation. Interestingly, both the relaxation of the hot carriers and the band-edge carrier recombination become slower as the size increases. The evolution in excited-state properties of this FCC series offers new insight into the structure-dependent properties of metal nanoclusters, which will benefit their optical energy harvesting and photocatalytic applications.« less

  12. Evolution of Excited-State Dynamics in Periodic Au 28, Au 36, Au 44, and Au 52 Nanoclusters

    DOE PAGES

    Zhou, Meng; Zeng, Chenjie; Sfeir, Matthew Y.; ...

    2017-08-10

    An understanding of the correlation between the atomic structure and optical properties of gold nanoclusters is essential for exploration of their functionalities and applications involving light harvesting and electron transfer. We report the femto-nanosecond excited state dynamics of a periodic series of face-centered cubic (FCC) gold nanoclusters (including Au 28, Au 36, Au 44, and Au 52), which exhibit a set of unique features compared with other similar sized clusters. Molecular-like ultrafast S n → S 1 internal conversions (i.e., radiationless electronic transitions) are observed in the relaxation dynamics of FCC periodic series. Excited-state dynamics with near-HOMO–LUMO gap excitation lacksmore » ultrafast decay component, and only the structural relaxation dominates in the dynamical process, which proves the absence of core–shell relaxation. Interestingly, both the relaxation of the hot carriers and the band-edge carrier recombination become slower as the size increases. The evolution in excited-state properties of this FCC series offers new insight into the structure-dependent properties of metal nanoclusters, which will benefit their optical energy harvesting and photocatalytic applications.« less

  13. A risk prediction model for determining appropriateness of CEA in patients with asymptomatic carotid artery stenosis.

    PubMed

    Conrad, Mark F; Kang, Jeanwan; Mukhopadhyay, Shankha; Patel, Virendra I; LaMuraglia, Glenn M; Cambria, Richard P

    2013-10-01

    The benefit of carotid endarterectomy (CEA) over medical therapy in patients with asymptomatic carotid artery stenosis is predicated upon a life expectancy of at least 5 years after the procedure. The goal of this study was to create a scoring system for prediction of 5-year survival after CEA that can be used to triage patients with ACAS. All patients who underwent CEA for severe asymptomatic carotid stenosis from 1989 to 2005 were identified. Long-term survival was determined by a review of hospital records and the social security death index. Because all patients had at least 5-year follow-up, a logistic regression of predictors of survival at 5 years was performed and the odds ratios associated with particular significant comorbidities were used to create a scoring system to predict survival. The scoring system was then validated within the cohort using the Hosmer-Lemeshow Test and a derivation/validation receiver operating characteristic (ROC) curve. There were 2004 CEA performed in 1791 patients. The average follow-up was 130 ± 49 months. The clinical profile of the cohort data included 84% hypertension, 56% coronary artery disease (CAD), 24% diabetes, and 71% on statins. The 30-day stroke rate was 1.1% and the death rate was 0.7%. The actual 5-year survival was 73%. Logistic regression yielded the following predictors of mortality: age (by decade) (odds ratio [OR] = 1.8, P < 0.0001), CAD (OR = 1.5, P = 0.0007), chronic obstructive pulmonary disease (OR = 2.5; P < 0.0001), diabetes (OR = 1.7, P < 0.0001), neck radiation (OR = 2.6, P = 0.005), no statin (OR = 2.1, P < 0.0001), and creatinine more than 1.5 (OR = 2.6, P < 0.0001). These variables were then assigned a hierarchal point scoring system in accordance with the OR value. The 5-year survival based on the scoring system was as follows: 0 to 5 points = 92.5%, 6 to 8 points = 83.6%, 9 to 11 points = 63.7%, 12 to 14 points = 46.5%, and more than 15 points = 33.8%. The Hosmer-Lemeshow test validated the

  14. Di-hadron correlations with identified leading hadrons in 200 GeV Au + Au and d + Au collisions at STAR

    NASA Astrophysics Data System (ADS)

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Averichev, G. S.; Bai, X.; Bairathi, V.; Banerjee, A.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandenburg, D.; Brandin, A. V.; Bunzarov, I.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Cervantes, M. C.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chattopadhyay, S.; Chen, X.; Chen, J. H.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; di Ruzza, B.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Engelage, J.; Eppley, G.; Esha, R.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Fisyak, Y.; Flores, C. E.; Fulek, L.; Gagliardi, C. A.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, S.; Gupta, A.; Guryn, W.; Hamad, A.; Hamed, A.; Haque, R.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Hofman, D. J.; Horvat, S.; Huang, T.; Huang, B.; Huang, H. Z.; Huang, X.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Jia, J.; Jiang, K.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z. H.; Kikoła, D. P.; Kisiel, A.; Kochenda, L.; Koetke, D. D.; Kosarzewski, L. K.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kumar, L.; Lamont, M. A. C.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, X.; Li, W.; Li, Z. M.; Li, Y.; Li, C.; Li, X.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Ma, G. L.; Ma, Y. G.; Ma, R.; Ma, L.; Magdy, N.; Majka, R.; Manion, A.; Margetis, S.; Markert, C.; Masui, H.; Matis, H. S.; McDonald, D.; Meehan, K.; Mei, J. C.; Minaev, N. G.; Mioduszewski, S.; Mishra, D.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nigmatkulov, G.; Niida, T.; Nogach, L. V.; Noh, S. Y.; Novak, J.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V.; Olvitt, D.; Page, B. S.; Pak, R.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Peterson, A.; Pile, P.; Pluta, J.; Poniatowska, K.; Porter, J.; Posik, M.; Poskanzer, A. M.; Pruthi, N. K.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Roy, A.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, B.; Sharma, M. K.; Shen, W. Q.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Singha, S.; Skoby, M. J.; Smirnov, N.; Smirnov, D.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stepanov, M.; Strikhanov, M.; Stringfellow, B.; Sumbera, M.; Summa, B.; Sun, Y.; Sun, Z.; Sun, X. M.; Sun, X.; Surrow, B.; Svirida, D. N.; Szelezniak, M. A.; Tang, A. H.; Tang, Z.; Tarnowsky, T.; Tawfik, A.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Todoroki, T.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vandenbroucke, M.; Varma, R.; Vasiliev, A. N.; Vertesi, R.; Videbæk, F.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, J. S.; Wang, F.; Wang, H.; Wang, G.; Wang, Y.; Wang, Y.; Webb, G.; Webb, J. C.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y. F.; Wu; Xiao, Z. G.; Xie, W.; Xin, K.; Xu, H.; Xu, Z.; Xu, Q. H.; Xu, Y. F.; Xu, N.; Yang, S.; Yang, Y.; Yang, Q.; Yang, Y.; Yang, C.; Yang, Y.; Ye, Z.; Ye, Z.; Yepes, P.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, Y.; Zhang, Z.; Zhang, J. B.; Zhang, J.; Zhang, X. P.; Zhang, S.; Zhang, J.; Zhao, J.; Zhong, C.; Zhou, L.; Zhu, X.; Zoulkarneeva, Y.

    2015-12-01

    The STAR Collaboration presents for the first time two-dimensional di-hadron correlations with identified leading hadrons in 200 GeV central Au + Au and minimum-bias d + Au collisions to explore hadronization mechanisms in the quark gluon plasma. The enhancement of the jet-like yield for leading pions in Au + Au data with respect to the d + Au reference and the absence of such an enhancement for leading non-pions (protons and kaons) are discussed within the context of a quark recombination scenario. The correlated yield at large angles, specifically in the ridge region, is found to be significantly higher for leading non-pions than pions. The consistencies of the constituent quark scaling, azimuthal harmonic model and a mini-jet modification model description of the data are tested, providing further constraints on hadronization.

  15. Fluorescently labeled chimeric anti-CEA antibody improves detection and resection of human colon cancer in a patient-derived orthotopic xenograft (PDOX) nude mouse model.

    PubMed

    Metildi, Cristina A; Kaushal, Sharmeela; Luiken, George A; Talamini, Mark A; Hoffman, Robert M; Bouvet, Michael

    2014-04-01

    The aim of this study was to evaluate a new fluorescently labeled chimeric anti-CEA antibody for improved detection and resection of colon cancer. Frozen tumor and normal human tissue samples were stained with chimeric and mouse antibody-fluorophore conjugates for comparison. Mice with patient-derived orthotopic xenografts (PDOX) of colon cancer underwent fluorescence-guided surgery (FGS) or bright-light surgery (BLS) 24 hr after tail vein injection of fluorophore-conjugated chimeric anti-CEA antibody. Resection completeness was assessed using postoperative images. Mice were followed for 6 months for recurrence. The fluorophore conjugation efficiency (dye/mole ratio) improved from 3-4 to >5.5 with the chimeric CEA antibody compared to mouse anti-CEA antibody. CEA-expressing tumors labeled with chimeric CEA antibody provided a brighter fluorescence signal on frozen human tumor tissues (P = 0.046) and demonstrated consistently lower fluorescence signals in normal human tissues compared to mouse antibody. Chimeric CEA antibody accurately labeled PDOX colon cancer in nude mice, enabling improved detection of tumor margins for more effective FGS. The R0 resection rate increased from 86% to 96% with FGS compared to BLS. Improved conjugating efficiency and labeling with chimeric fluorophore-conjugated antibody resulted in better detection and resection of human colon cancer in an orthotopic mouse model. © 2013 Wiley Periodicals, Inc.

  16. A dye-sensitized solar cell acting as the electrical reading box of an immunosensor: Application to CEA determination.

    PubMed

    Truta, Liliana A A N A; Moreira, Felismina T C; Sales, M Goreti F

    2018-06-01

    Monitoring cancer biomarkers in biological fluids has become a key tool for disease diagnosis, which should be of easy access anywhere in the world. The possibility of reducing basic requirements in the field of electrochemical biosensing may open doors in this direction. This work proposes for this purpose an innovative electrochemical immunosensing system using a photovoltaic cell as an electrical reading box. Immunosensing ensures accuracy, the electrochemical-ground of the device ensures sensitivity and detectability, and the photovoltaic cell drives the system towards electrical autonomy. As proof-of-concept, Carcinoembryonic antigen (CEA) was used herein, a cancer biomarker of clinical relevance. In brief, a conductive glass with a fluorine doped tin oxide film was used as conductive support and modified with anti-CEA by means of a bottom-up approach. All stages involved in the biochemical modification of the FTO surface were followed by electrochemical techniques, namely electrochemical impedance spectroscopy and cyclic voltammetry. This electrode acted as counter electrode of a dye-sensitized solar cells, and the electrical output of this cell was monitored for the different concentrations of CEA. Under optimized conditions, the device displayed a linear behaviour against CEA concentration, from 5 pg/mL to 15 ng/mL. The immunosensor was applied to the analysis of CEA in urine from healthy individual and spiked with the antigen. Overall, the presented approach demonstrates that photovoltaic cells may be employed as an electrical reading box of electrochemical biosensors, yielding a new direction towards autonomous electrochemical biosensing. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  17. The concentration of CYFRA 21-1, NSE and CEA in cerebro-spinal fluid can be useful indicators for diagnosis of meningeal carcinomatosis of lung cancer.

    PubMed

    Wang, Peng; Piao, Yingzhe; Zhang, Xiaohui; Li, Wenliang; Hao, Xishan

    2013-01-01

    We aimed to investigate the concentration of CYFRA 21-1, NSE and CEA in cerebro-spinal fluid (CSF) and to explore their clinical value in the meningeal carcinomatosis (MC) of lung cancer. So that, sensitive and specificity of CSF examination can be improved in the initial diagnosis of MC. A total of 35 lung cancer patients and 35 patients with benign brain tumor in the same period enrolled in this study. The concentrations of tumor markers CEA, CYFRA 21-1 and NSE in CSF and peripheral blood were examined. The concentrations of three tumor markers of CYFRA 21-1, NSE and CEA in blood serum and CSF were obviously higher than that of benign disease group. In MC patients, the concentrations of three tumor markers of CYFRA 21-1, NSE and CEA in blood serum were significant lower than that in CSF. The maximum of Youden's index was identified as the cutoff value of indicator of MC in three tumor markers in CSF which were CEA > 4.7 μg/L, NSE > 14.6 μg/L and CYFRA21-1 > 5.5 μg/L respectively. Based on the cutoff values, the CEA had the highest sensitivity while the CYFRA21-1 had the highest specificitiy. Three tumor markers in the CSF had higher positive rate than those in blood serum. We combined the levels of CEA, NSE and CYFRA21-1 in CSF to diagnosis of MC. Positive of CEA or CYFRA21-1 had the greatest sensitivity of 100% while the specificity of 91.4%; the positive of both CEA and CYFRA21-1 had the highest specificity of 100% while the sensitivity of 74.3%. Both positive predictive value and negative predictive value were 100% when combination positive were confirmed when the all three markers were positive. The combination of CEA and CYFRA21-1 can be recommended in early screening of meningeal carcinoma. Especially, for the patient who was difficult to be diagnosed by CSF histology and MRI, it will be a useful auxiliary marker in diagnosis of MC. The combination of CEA, NSE and CYFRA21-1 can be an effective clinically confirmation and exclusively diagnose indictor of

  18. Connected Au network in annealed Ni/Au thin films on p-GaN

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lee, S. P.; Jang, H. W.; Noh, D. Y.

    2007-11-12

    We report the formation of a connected Au network in annealed Ni/Au thin films on p-GaN, which was studied by scanning electron microscopy, transmission electron microscopy, and synchrotron x-ray diffraction. As the Ni was oxidized into NiO upon annealing at 530 deg. C in air, the Au layer was transformed to an interconnected network with an increased thickness. During annealing, Ni atoms diffuse out onto the Au through defects to form NiO, while Au atoms replace the Ni positions. The Au network grows downward until it reaches the p-GaN substrate, and NiO columns fill the space between the Au network.

  19. CEA SMAD 2016 Digitizer Evaluation.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Merchant, Bion J.

    Sandia National Laboratories has tested and evaluated an updated SMAD digitizer, developed by the French Alternative Energies and Atomic Energy Commission (CEA). The SMAD digitizers are intended to record sensor output for seismic and infrasound monitoring applications. The purpose of this digitizer evaluation is to measure the performance characteristics in such areas as power consumption, input impedance, sensitivity, full scale, self-noise, dynamic range, system noise, response, passband, and timing. The SMAD digitizers have been updated since their last evaluation by Sandia to improve their performance when recording at a sample rate of 20 Hz for infrasound applications and 100 Hzmore » for hydro-acoustic seismic stations. This evaluation focuses primarily on the 20 Hz and 100 Hz sample rates. The SMAD digitizers are being evaluated for potential use in the International Monitoring System (IMS) of the Comprehensive Nuclear Test- Ban-Treaty Organization (CTBTO).« less

  20. Plasmon-enhanced versatile optical nonlinearities in a Au-Ag-Au multi-segmental hybrid structure.

    PubMed

    Yao, Lin-Hua; Zhang, Jun-Pei; Dai, Hong-Wei; Wang, Ming-Shan; Zhang, Lu-Man; Wang, Xia; Han, Jun-Bo

    2018-06-27

    A Au-Ag-Au multi-segmental hybrid structure has been synthesized by using an electrodeposition method based on an anodic aluminum oxide (AAO) membrane. The third-order optical nonlinearities, second harmonic generation (SHG) and photoluminescence (PL) properties containing ultrafast supercontinuum generation and plasmon mediated thermal emission have been investigated. Significant optical enhancements have been obtained near surface plasmon resonance wavelength in all the abovementioned nonlinear processes. Comparative studies between the Au-Ag-Au multi-segmental hybrid structure and the corresponding single-component Au and Ag hybrid structures demonstrate that the Au-Ag-Au multi-segmental hybrid structure has much larger optical nonlinearities than its counterparts. These results demonstrate that the Au-Ag-Au hybrid structure is a promising candidate for applications in plasmonic devices and enhancement substrates.

  1. Di-hadron correlations with identified leading hadrons in 200 GeV Au + Au and d + Au collisions at STAR

    DOE PAGES

    Adamczyk, L.

    2015-10-23

    The STAR Collaboration presents for the first time two-dimensional di-hadron correlations with identified leading hadrons in 200 GeV central Au + Au and minimum-bias d + Au collisions to explore hadronization mechanisms in the quark gluon plasma. The enhancement of the jet-like yield for leading pions in Au + Au data with respect to the d + Au reference and the absence of such an enhancement for leading non-pions (protons and kaons) are discussed within the context of a quark recombination scenario. The correlated yield at large angles, specifically in the ridge region, is found to be significantly higher formore » leading non-pions than pions. As a result, the consistencies of the constituent quark scaling, azimuthal harmonic model and a mini-jet modification model description of the data are tested, providing further constraints on hadronization.« less

  2. Biosynthesis and stabilization of Au and Au Ag alloy nanoparticles by fungus, Fusarium semitectum

    NASA Astrophysics Data System (ADS)

    Dasaratrao Sawle, Balaji; Salimath, Basavaraja; Deshpande, Raghunandan; Dhondojirao Bedre, Mahesh; Krishnamurthy Prabhakar, Belawadi; Venkataraman, Abbaraju

    2008-09-01

    Crystallized and spherical-shaped Au and Au-Ag alloy nanoparticles have been synthesized and stabilized using a fungus, F . semitectum in an aqueous system. Aqueous solutions of chloroaurate ions for Au and chloroaurate and Ag+ ions (1 : 1 ratio) for Au-Ag alloy were treated with an extracellular filtrate of F . semitectum biomass for the formation of Au nanoparticles (AuNP) and Au-Ag alloy nanoparticles (Au-AgNP). Analysis of the feasibility of the biosynthesized nanoparticles and core-shell alloy nanoparticles from fungal strains is particularly significant. The resultant colloidal suspensions are highly stable for many weeks. The obtained Au and Au-Ag alloy nanoparticles were characterized by the surface plasmon resonance (SPR) peaks using a UV-vis spectrophotometer, and the structure, morphology and size were determined by Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), and transmission electron microscopy (TEM). Possible optoelectronics and medical applications of these nanoparticles are envisaged.

  3. Methodology for Assessing Disruptions (MAD) Game Part I: Report and Analysis

    DTIC Science & Technology

    2012-12-01

    élaborées dans le Guide de planification fonctionnelle du groupe du SMA(S& T ). Le présent mémorandum technique est principalement destiné au Bureau du...le Guide de planification fonctionnelle du groupe du SMA(S& T ). Le présent mémorandum technique est principalement destiné au Bureau du scientifique en...2010 2012-009 Principal Author Original signed by G . Adlakha-Hutcheon, M. Hazen, P. Hubbard, S. McLelland, K. Sprague G . Adlakha

  4. Aspects descriptifs du VIH/SIDA chez les sujets âgés de 50 ans et plus suivis au Centre de Traitement Agréé de Bafoussam - Cameroun

    PubMed Central

    Mbopi-Kéou, François-Xavier; Djomassi, Lucienne Dempouo; Monebenimp, Francisca

    2012-01-01

    Introduction La littérature scientifique dispose de très peu de données relatives à l’épidémiologie du VIH chez les sujets âgés en Afrique subsaharienne. Au Cameroun, les caractéristiques épidémiologiques de l'infection par le VIH chez les sujets âgés de 50 ans et plus ne sont pas documentées. Méthodes Dans une étude de cohorte rétrospective et une enquête transversale, nous avons comparé les caractéristiques clinico-biologiques et la survie post thérapeutique des patients âgés de 50 ans et plus, sous traitement antirétroviral au Centre de Traitement Agrée de Bafoussam - Cameroun, aux adultes plus jeunes. Résultats L’âge moyen était de 39 ans, les extrêmes étant 17 et 88 ans. Les sujets âgés de 50 ans et plus représentaient 14,1% des cas. Les plus âgés étaient moins bien informés sur les modes de transmission du virus (p = 0,04). Leur séropositivité au VIH était le plus souvent découverte au décours d'une infection opportuniste (p = 0,02). La fréquence de comorbidité était significativement plus élevée chez les personnes âgées de 50 ans et plus (p < 10-5). Nous n'avons pas retrouvé une association statistiquement significative entre l'observance thérapeutique et l’âge (p = 0,83). La survie post-thérapeutique n’était pas significativement liée à l’âge (p = 0,81). Conclusion Les sujets âgés ne sont pas à l'abri du VIH. La promotion du dépistage et les programmes d’éducation sanitaire relatifs au VIH/SIDA devraient être renforcés au sein de cette communauté déjà affaiblie par le poids de l’âge, afin de réduire l'incidence du SIDA et de leur assurer prise en charge précoce. PMID:23133707

  5. Integration des sciences et de la langue: Creation et experimentation d'un modele pedagogique pour ameliorer l'apprentissage des sciences en milieu francophone minoritaire

    NASA Astrophysics Data System (ADS)

    Cormier, Marianne

    Les faibles resultats en sciences des eleves du milieu francophone minoritaire, lors d'epreuves au plan national et international, ont interpelle la recherche de solutions. Cette these avait pour but de creer et d'experimenter un modele pedagogique pour l'enseignement des sciences en milieu linguistique minoritaire. En raison de la presence de divers degres de francite chez la clientele scolaire de ce milieu, plusieurs elements langagiers (l'ecriture, la discussion et la lecture) ont ete integres a l'apprentissage scientifique. Nous avions recommande de commencer le processus d'apprentissage avec des elements langagiers plutot informels (redaction dans un journal, discussions en dyades...) pour progresser vers des activites langagieres plus formelles (redaction de rapports ou d'explications scientifiques). En ce qui a trait a l'apprentissage scientifique, le modele preconisait une demarche d'evolution conceptuelle d'inspiration socio-constructiviste tout en s'appuyant fortement sur l'apprentissage experientiel. Lors de l'experimentation du modele, nous voulions savoir si celui-ci provoquait une evolution conceptuelle chez les eleves, et si, simultanement, le vocabulaire scientifique de ces derniers s'enrichissait. Par ailleurs, nous cherchions a comprendre comment les eleves vivaient leurs apprentissages dans le cadre de ce modele pedagogique. Une classe de cinquieme annee de l'ecole de Grande-Digue, dans le Sud-est du Nouveau-Brunswick, a participe a la mise a l'essai du modele en etudiant les marais sales locaux. Lors d'entrevues initiales, nous avons remarque que les connaissances des eleves au sujet des marais sales etaient limitees. En effet, s'ils etaient conscients que les marais etaient des lieux naturels, ils ne pouvaient pas necessairement les decrire avec precision. Nous avons egalement constate que les eleves utilisaient surtout des mots communs (plantes, oiseaux, insectes) pour decrire le marais. Les resultats obtenus indiquent que les eleves ont

  6. Fermi surfaces properties of AuAl2, AuGa2, and AuIn2 with the CaF2-type cubic structure

    NASA Astrophysics Data System (ADS)

    Nishimura, K.; Kakihana, M.; Suzuki, F.; Yara, T.; Hedo, M.; Nakama, T.; Ōnuki, Y.; Harima, H.

    2018-05-01

    We grew high-quality single crystals of AuAl2, AuGa2, and AuIn2 with the fluorite (CaF2)-type cubic structure and determined the Fermi surface properties by the de Haas-van Alphen (dHvA) experiments using full-potential LAPW bad calculations. The Fermi surface and optical properties for three compounds were once studied from an interest of colors because AuAl2 has a striking bright reddish-purple color, whereas AuGa2 and AuIn2 are, respectively, neutral and bluish. The detected dHvA frequencies in the present study are found to be in a wide range of (0.1-13)×107 Oe. The main dHvA branches for three compounds are in excellent agreement with the theoretical ones, but some dHvA branches with small dHvA frequencies are slightly deviated from the theoretical ones, especially in AuGa2 and AuIn2.

  7. [Clinical value of combined determination of serum and pleural effusion level of CEA,CYFRA21-1, TPS in the diagnosis of lung cancer].

    PubMed

    Huang, Fang; Wang, Xiao-li; Yang, Lian; Yin, Bin-xia; Geng, Yan; Li, Ting-ting

    2008-04-01

    To study the clinical value of combined determination of carcinoembryonic antigen (CEA), cytokeratin-19-fragments (CYFRA21-1) and tissue polypeptide specific antigen (TPS) levels in both serum and pleural effusion in the diagnosis of lung cancer. The levels of CEA, CYFRA21-1 and TPS in serum and pleural effusion were measured in 78 patients with lung cancer and 45 patients with benign lung disease by using electrochemiluminescence and ELISA methods respectively. The levels of CEA, CYFRA21-1 and TPS in pleural effusion of patients with lung cancer were much higher than those with benign lung disease (P<0.01). The levels of CEA and TPS in serum of patients with lung cancer were much higher than those with benign lung disease (P<0.05, P<0.01). It was also found that the levels of these tumor markers in pleural effusion were higher and more sensitive than those in sera, especially TPS. TPS showed the highest sensitivity in single tumor marker detection, and TPS+CYFRA21-1+ CEA showed the highest sensitivity and accuracy in combined tumor marker detection for diagnosis of lung cancer in pleural effusion. The combined detection of CEA, CYFRA21-1 and TPS in pleural effusion showed higher sensitivity, better accuracy and higher clinical value than those in serum for diagnosis of lung cancer.

  8. How Does Amino Acid Ligand Modulate Au Core Structure and Characteristics in Peptide Coated Au Nanocluster?

    PubMed

    Li, Nan; Li, Xu; Zhao, Hongkang; Zhao, Lina

    2018-03-01

    The atomic structures and the corresponding physicochemical properties of peptide coated Au nanoclusters determine their distinctive biological targeting applications. To learn the modulation of amino acid ligand on the atomic structure and electronic characteristics of coated Au core is the fundamental knowledge for peptide coated Au nanocluster design and construction. Based on our recent coated Au nanocluster configuration study (Nanoscale, 2016, 8, 11454), we built the typically simplified Au13(Cys-Au-Cys) system to more clearly learn the basic modulation information of amino acid ligand on Au core by the density functional theory (DFT) calculations. There are two isomers as ligand adjacent bonding (Iso1) and diagonal bonding (Iso2) to Au13 cores. The geometry optimizations indicate the adjacent bonding Iso1 is more stable than Iso2. More important, the Au13 core of Iso1 distorts much more significantly than that of Iso2 by Cys-Au-Cys bonding through the root-mean-square deviation (RMSD) analysis, which modulate their electronic characteristics in different ways. In addition, the frontier molecular orbital results of Au13(Cys-Au-Cys) isomers confirm that the Au cores mainly determine the blue shifts of Au13(Cys-Au-Cys) systems versus the original Au13 core in their UV-visible absorption spectrum studies. The configuration of Au13 core performs deformation under Cys-Au-Cys ligand modulation to reach new stability with distinct atomic structure and electronic properties, which could be the theory basis for peptide coated AuNCs design and construction.

  9. Comparison of the space-time extent of the emission source in d +Au and Au + Au collisions at √{sNN} = 200 GeV

    NASA Astrophysics Data System (ADS)

    Ajitanand, N. N.; Phenix Collaboration

    2014-11-01

    Two-pion interferometry measurements in d +Au and Au + Au collisions at √{sNN} = 200 GeV are used to extract and compare the Gaussian source radii Rout, Rside and Rlong, which characterize the space-time extent of the emission sources. The comparisons, which are performed as a function of collision centrality and the mean transverse momentum for pion pairs, indicate strikingly similar patterns for the d +Au and Au + Au systems. They also indicate a linear dependence of Rside on the initial transverse geometric size R bar , as well as a smaller freeze-out size for the d +Au system. These patterns point to the important role of final-state re-scattering effects in the reaction dynamics of d +Au collisions.

  10. Combination of a poxvirus-based vaccine with a cyclooxygenase-2 inhibitor (celecoxib) elicits antitumor immunity and long-term survival in CEA.Tg/MIN mice.

    PubMed

    Zeytin, Hasan E; Patel, Arti C; Rogers, Connie J; Canter, Daniel; Hursting, Stephen D; Schlom, Jeffrey; Greiner, John W

    2004-05-15

    The present study was designed to determine whether: (a) chronic administration of dietary celecoxib (Celebrex), a potent nonsteroidal anti-inflammatory drug, which targets the cyclooxygenase-2 (COX-2) enzyme, negatively impacts host immunity; and (b) celecoxib can be coupled with a poxvirus-based vaccine to impact tumor burden in a murine tumor model of spontaneous adenomatous polyposis coli. Naive mice fed the celecoxib-supplemented diets developed eosinophilia with lowered plasma prostaglandin E(2) levels and reduced COX-2 mRNA expression levels in their splenic T cells. Responses of splenic T, B, and natural killer cells to broad-based and antigen-specific stimuli were, for the most part, unchanged in those mice as well as COX-2 knockout mice; exceptions included: (a) reduced IFN-gamma production by concanavalin A- or antigen-stimulated T cells; and (b) heightened lipopolysaccharide response of naive B cells from mice fed a diet supplemented with 1000 ppm of celecoxib. When transgenic mice that express the human carcinoembryonic antigen (CEA) gene (CEA transgenic) were bred with mice bearing a mutation in the Apc(Delta850) gene (multiple intestinal neoplasia mice), the progeny (CEA transgenic/multiple intestinal neoplasia) spontaneously develop multiple intestinal neoplasms that overexpress CEA and COX-2. Beginning at 30 days of age, the administration of a diversified prime/boost recombinant CEA-poxvirus-based vaccine regimen or celecoxib (1000 ppm)-supplemented diet reduced the number of intestinal neoplasms by 54% and 65%, respectively. Combining the CEA-based vaccine with the celecoxib-supplemented diet reduced tumor burden by 95% and significantly improved overall long-term survival. Both tumor reduction and improved overall survival were achieved without any evidence of autoimmunity directed at CEA-expressing or other normal tissues. Celecoxib is prescribed for the treatment of familial adenomatous polyposis in humans, and the CEA-based vaccines have been

  11. The extraction characteristic of Au-Ag from Au concentrate by thiourea solution

    NASA Astrophysics Data System (ADS)

    Kim, Bongju; Cho, Kanghee; On, Hyunsung; Choi, Nagchoul; Park, Cheonyoung

    2013-04-01

    The cyanidation process has been used commercially for the past 100 years, there are ores that are not amenable to treatment by cyanide. Interest in alternative lixiviants, such as thiourea, halogens, thiosulfate and malononitrile, has been revived as a result of a major increase in gold price, which has stimulated new developments in extraction technology, combined with environmental concern. The Au extraction process using the thiourea solvent has many advantages over the cyanidation process, including higher leaching rates, faster extraction time and less than toxicity. The purpose of this study was investigated to the extraction characteristic of Au-Ag from two different Au concentrate (sulfuric acid washing and roasting) under various experiment conditions (thiourea concentration, pH of solvent, temperature) by thiourea solvent. The result of extraction experiment showed that the Au-Ag extraction was a fast extraction process, reaching equilibrium (maximum extraction rate) within 30 min. The Au-Ag extraction rate was higher in the roasted concentrate than in the sulfuric acid washing. The higher the Au-Ag extraction rate (Au - 70.87%, Ag - 98.12%) from roasted concentrate was found when the more concentration of thiourea increased, pH decreased and extraction temperature increased. This study informs extraction method basic knowledge when thiourea was a possibility to eco-/economic resources of Au-Ag utilization studies including the hydrometallurgy.

  12. Structure-activity relationships in cytotoxic Au(I)/Au(III) complexes derived from 2-(2'-pyridyl)benzimidazole.

    PubMed

    Maiore, Laura; Aragoni, Maria Carla; Deiana, Carlo; Cinellu, Maria Agostina; Isaia, Francesco; Lippolis, Vito; Pintus, Anna; Serratrice, Maria; Arca, Massimiliano

    2014-04-21

    Gold(I) and gold(III) complexes derived from 2-(2'-pyridyl)benzimidazole (pbiH) were proven to be a promising class of in vitro antitumor agents against A2780 human ovarian cancer cells. In this paper, a comparative electrochemical, UV-vis absorption, and emission spectroscopic investigation is reported on pbiH, the two mononuclear Au(III) complexes [(pbi)AuX2] (X = Cl (1), AcO (2)), the four mononuclear Au(I) derivatives [(pbiH)AuCl] (3), [(pbiH)Au(PPh3)]PF6 ((4(+))(PF6(-))), [(pbi)Au(PPh3)] (5), and [(pbi)Au(TPA)] (6), the three mixed-valence Au(III)/Au(I) complexes [(μ-pbi)Au2Cl3] (7), [(Ph3P)Au(μ-pbi)AuX2]PF6 (X = Cl ((8(+))(PF6(-))), AcO ((9(+))(PF6(-)))), and the binuclear Au(I)-Au(I) compound [(μ-pbi)Au2(PPh3)2]PF6 ((10(+))(PF6(-))). All complexes feature irreversible reduction processes related to the Au(III)/Au(I) or Au(I)/Au(0) processes and peculiar luminescent emission at about 360-370 nm in CH2Cl2, with quantum yields that are remarkably lower ((0.7-14.5) × 10(-2)) in comparison to that determined for the free pbiH ligand (31.5 × 10(-2)) in the same solvent. The spectroscopic and electrochemical properties of all complexes were interpreted on the grounds of time-dependent PBE0/DFT calculations carried out both in the gas phase and in CH2Cl2 implicitly considered within the IEF-PCM SCRF approach. The electronic structure of the complexes, and in particular the energy and composition of the Kohn-Sham LUMOs, can be related to the antiproliferative properties against the A2780 ovarian carcinoma cell line, providing sound quantitative structure-activity relationships and shedding a light on the role played by the global charge and nature of ancillary ligands in the effectiveness of Au-based antitumor drugs.

  13. LHC, le Big Bang en éprouvette

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    None

    Notre compréhension de l’Univers est en train de changer… Bar des Sciences - Tout public Débat modéré par Marie-Odile Montchicourt, journaliste de France Info. Evenement en vidéoconférence entre le Globe de la science et de l’innovation, le bar le Baloard de Montpellier et la Maison des Métallos à Paris. Intervenants au CERN : Philippe Charpentier et Daniel Froideveaux, physiciens au CERN. Intervenants à Paris : Vincent Bontemps, philosophe et chercheur au CEA ; Jacques Arnould, philosophe, historien des sciences et théologien, Jean-Jacques Beineix, réalisateur, producteur, scénariste de cinéma. Intervenants à Montpellier (LPTA) : André Neveu, physicien théoricien et directeur demore » recherche au CNRS ; Gilbert Moultaka, physicien théoricien et chargé de recherche au CNRS. Partenariat : CERN, CEA, IN2P3, Université MPL2 (LPTA) Dans le cadre de la Fête de la science 2008.« less

  14. Charged hadron transverse momentum distributions in Au+Au collisions at S=200 GeV

    NASA Astrophysics Data System (ADS)

    Roland, Christof; PHOBOS Collaboration; Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2003-03-01

    We present transverse momentum distributions of charged hadrons produced in Au+Au collisions at sqrt(s_NN) = 200 GeV. The evolution of the spectra for transverse momenta p_T from 0.25 to 5GeV/c is studied as a function of collision centrality over a range from 65 to 344 participating nucleons. We find a significant change of the spectral shape between proton-antiproton and peripheral Au+Au collisions. Comparing peripheral to central Au+Au collisions, we find that the yields at the highest p_T exhibit approximate scaling with the number of participating nucleons, rather than scaling with the number of binary collisions.

  15. Corrigendum to “Suppression of Υ production in d+Au and Au+Au collisions at √ SNN = 200 GeV" [Phys. Lett. B 735 (2014) 127-137

    DOE PAGES

    Adamczyk, L.

    2015-04-01

    We report measurements of Υ meson production in p + p, d + Au, and Au+Au collisions using the STAR detector at RHIC. We compare the Υ yield to the measured cross section in p + p collisions in order to quantify any modifications of the yield in cold nuclear matter using d + Au data and in hot nuclear matter using Au+Au data separated into three centrality classes. Our p + p measurement is based on three times the statistics of our previous result. We obtain a nuclear modification factor for Upsilon (1S + 2S + 3S) in themore » rapidity range |y| < 1 in d + Au collisions of R dAu = 0.79 ± 0.24(stat.) ± 0.03(syst.) ± 0.10(p + p syst.). A comparison with models including shadowing and initial state parton energy loss indicates the presence of additional cold-nuclear matter suppression. Similarly, in the top 10% most-central Au + Au collisions, we measure a nuclear modification factor of R AA = 0.49 ±0.1(stat.) ±0.02(syst.) ±0.06(p + p syst.), which is a larger suppression factor than that seen in cold nuclear matter. Our results are consistent with complete suppression of excited-state Upsilon mesons in Au + Au collisions. The additional suppression in Au + Au is consistent with the level expected in model calculations that include the presence of a hot, deconfined Quark–Gluon Plasma. However, understanding the suppression seen in d + Au is still needed before any definitive statements about the nature of the suppression in Au + Au can be made.« less

  16. Corrigendum to “Suppression of Υ production in d+Au and Au+Au collisions at √ SNN = 200 GeV" [Phys. Lett. B 735 (2014) 127-137

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Adamczyk, L.

    We report measurements of Υ meson production in p + p, d + Au, and Au+Au collisions using the STAR detector at RHIC. We compare the Υ yield to the measured cross section in p + p collisions in order to quantify any modifications of the yield in cold nuclear matter using d + Au data and in hot nuclear matter using Au+Au data separated into three centrality classes. Our p + p measurement is based on three times the statistics of our previous result. We obtain a nuclear modification factor for Upsilon (1S + 2S + 3S) in themore » rapidity range |y| < 1 in d + Au collisions of R dAu = 0.79 ± 0.24(stat.) ± 0.03(syst.) ± 0.10(p + p syst.). A comparison with models including shadowing and initial state parton energy loss indicates the presence of additional cold-nuclear matter suppression. Similarly, in the top 10% most-central Au + Au collisions, we measure a nuclear modification factor of R AA = 0.49 ±0.1(stat.) ±0.02(syst.) ±0.06(p + p syst.), which is a larger suppression factor than that seen in cold nuclear matter. Our results are consistent with complete suppression of excited-state Upsilon mesons in Au + Au collisions. The additional suppression in Au + Au is consistent with the level expected in model calculations that include the presence of a hot, deconfined Quark–Gluon Plasma. However, understanding the suppression seen in d + Au is still needed before any definitive statements about the nature of the suppression in Au + Au can be made.« less

  17. Development activities on NIR large format MCT detectors for astrophysics and space science at CEA and SOFRADIR

    NASA Astrophysics Data System (ADS)

    Boulade, Olivier; Moreau, Vincent; Mulet, Patrick; Gravrand, Olivier; Cervera, Cyril; Zanatta, Jean-Paul; Castelein, Pierre; Guellec, Fabrice; Fièque, Bruno; Chorier, Philippe; Roumegoux, Julien

    2016-07-01

    CEA and SOFRADIR have been manufacturing and characterizing near infrared detectors in the frame of ESA's near infrared large format sensor array roadmap to develop a 2Kx2K large format low flux low noise device for space applications such as astrophysics. These detectors use HgCdTe as the absorbing material and p/n diode technology. The technological developments (photovoltaic technology, readout circuit, ...) are shared between CEA/LETI and SOFRADIR, both in Grenoble, while most of the performances are evaluated at CEA/IRFU in Saclay where a dedicated test facility has been developed, in particular to measure very low dark currents. The paper will present the current status of these developments at the end of ESA's NIRLFSA phase 2. The performances of the latest batch of devices meet or are very close to all the requirements (quantum efficiency, dark current, cross talk, readout noise, ...) even though a glow induced by the ROIC prevents the accurate measurement of the dark current. The current devices are fairly small, 640x512 15μm pixels, and the next phase of activity will target the development of a full size 2Kx2K detector. From the design and development, to the manufacturing and finally the testing, that type of detector requests a high level of mastering. An appropriate manufacturing and process chain compatible with such a size is needed at industrial level and results obtained with CEA technology coupled with Sofradir industrial experience and work on large dimension detector allow French actors to be confident to address this type of future missions.

  18. Diphosphine-protected ultrasmall gold nanoclusters: opened icosahedral Au 13 and heart-shaped Au 8 clusters

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhang, Shan-Shan; Feng, Lei; Senanayake, Ravithree D.

    Two ultrasmall gold clusters, Au 13 and Au 8 , were identified as a distorted I h icosahedral Au 13 and edge-shared “core + 4 exo ” structure Au 8 S 2 cores, respectively. They showed interesting luminescence and electrochemical properties.

  19. Diphosphine-protected ultrasmall gold nanoclusters: opened icosahedral Au 13 and heart-shaped Au 8 clusters

    DOE PAGES

    Zhang, Shan-Shan; Feng, Lei; Senanayake, Ravithree D.; ...

    2018-01-01

    Two ultrasmall gold clusters, Au 13 and Au 8 , were identified as a distorted I h icosahedral Au 13 and edge-shared “core + 4 exo ” structure Au 8 S 2 cores, respectively. They showed interesting luminescence and electrochemical properties.

  20. Identified particle distributions in pp and Au+Au collisions atsqrt sNN=200 GeV

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Adams, J.; Adler, C.; Aggarwal, M.M.

    2003-10-06

    Transverse mass and rapidity distributions for charged pions, charged kaons, protons and antiprotons are reported for {radical}sNN = 200 GeV pp and Au+Au collisions at RHIC. The transverse mass distributions are rapidity independent within |y| < 0.5, consistent with a boost-invariant system in this rapidity interval. Spectral shapes and relative particle yields are similar in pp and peripheral Au+Au collisions and change smoothly to central Au+Au collisions. No centrality dependence was observed in the kaon and antiproton production rates relative to the pion production rate from medium-central to central collisions. Chemical and kinetic equilibrium model fits to our data revealmore » strong radial flow and relatively long duration from chemical to kinetic freeze-out in central Au+Au collisions. The chemical freeze-out temperature appears to be independent of initial conditions at RHIC energies.« less

  1. Charged hadron transverse momentum distributions in Au+Au collisions at √ SNN = 200 GeV

    NASA Astrophysics Data System (ADS)

    Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.; van Nieuwenhuizen, Gerrit; PHOBOS Collaboration

    2003-04-01

    We present transverse momentum distributions of charged hadrons produced in Au+Au collisions at √ SNN = 200 GeV. The evolution of the spectra for transverse momenta p T from 0.25 to 5 GeV/C is studied as a function of collision centrality. We find a significant change of the spectral shape between proton-antiproton and peripheral Au+Au collisions. When comparing peripheral to central Au+Au collisions, we find that the yields at the highest p T exhibit approximate scaling with the number of participating nucleons, rather than scaling with the number of binary collisions.

  2. Synthesis, structure, and bonding in K12Au21Sn4. A polar intermetallic compound with dense Au20 and open AuSn4 layers.

    PubMed

    Li, Bin; Kim, Sung-Jin; Miller, Gordon J; Corbett, John D

    2009-12-07

    The new phase K(12)Au(21)Sn(4) has been synthesized by direct reaction of the elements at elevated temperatures. Single crystal X-ray diffraction established its orthorhombic structure, space group Pmmn (No. 59), a = 12.162(2); b = 18.058(4); c = 8.657(2) A, V = 1901.3(7) A(3), and Z = 2. The structure consists of infinite puckered sheets of vertex-sharing gold tetrahedra (Au(20)) that are tied together by thin layers of alternating four-bonded-Sn and -Au atoms (AuSn(4)). Remarkably, the dense but electron-poorer blocks of Au tetrahedra coexist with more open and saturated Au-Sn layers, which are fragments of a zinc blende type structure that maximize tetrahedral heteroatomic bonding outside of the network of gold tetrahedra. LMTO band structure calculations reveal metallic properties and a pseudogap at 256 valence electrons per formula unit, only three electrons fewer than in the title compound and at a point at which strong Au-Sn bonding is optimized. Additionally, the tight coordination of the Au framework atoms by K plays an important bonding role: each Au tetrahedra has 10 K neighbors and each K atom has 8-12 Au contacts. The appreciably different role of the p element Sn in this structure from that in the triel members in K(3)Au(5)In and Rb(2)Au(3)Tl appears to arise from its higher electron count which leads to better p-bonding (valence electron concentrations = 1.32 versus 1.22).

  3. Evidence from d+Au measurements for final-state suppression of high-p(T) hadrons in Au+Au collisions at RHIC.

    PubMed

    Adams, J; Adler, C; Aggarwal, M M; Ahammed, Z; Amonett, J; Anderson, B D; Anderson, M; Arkhipkin, D; Averichev, G S; Badyal, S K; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellwied, R; Berger, J; Bezverkhny, B I; Bhardwaj, S; Bhaskar, P; Bhati, A K; Bichsel, H; Billmeier, A; Bland, L C; Blyth, C O; Bonner, B E; Botje, M; Boucham, A; Brandin, A; Bravar, A; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca Sánchez, M; Carroll, J; Castillo, J; Castro, M; Cebra, D; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, Y; Chernenko, S P; Cherney, M; Chikanian, A; Choi, B; Christie, W; Coffin, J P; Cormier, T M; Cramer, J G; Crawford, H J; Das, D; Das, S; Derevschikov, A A; Didenko, L; Dietel, T; Dong, X; Draper, J E; Du, F; Dubey, A K; Dunin, V B; Dunlop, J C; Dutta Majumdar, M R; Eckardt, V; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Fachini, P; Faine, V; Faivre, J; Fatemi, R; Filimonov, K; Filip, P; Finch, E; Fisyak, Y; Flierl, D; Foley, K J; Fu, J; Gagliardi, C A; Ganti, M S; Gagunashvili, N; Gans, J; Gaudichet, L; Germain, M; Geurts, F; Ghazikhanian, V; Ghosh, P; Gonzalez, J E; Grachov, O; Grigoriev, V; Gronstal, S; Grosnick, D; Guedon, M; Guertin, S M; Gupta, A; Gushin, E; Gutierrez, T D; Hallman, T J; Hardtke, D; Harris, J W; Heinz, M; Henry, T W; Heppelmann, S; Herston, T; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horsley, M; Huang, H Z; Huang, S L; Humanic, T J; Igo, G; Ishihara, A; Jacobs, P; Jacobs, W W; Janik, M; Johnson, I; Jones, P G; Judd, E G; Kabana, S; Kaneta, M; Kaplan, M; Keane, D; Kiryluk, J; Kisiel, A; Klay, J; Klein, S R; Klyachko, A; Koetke, D D; Kollegger, T; Konstantinov, A S; Kopytine, M; Kotchenda, L; Kovalenko, A D; Kramer, M; Kravtsov, P; Krueger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kunde, G J; Kunz, C L; Kutuev, R Kh; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; Lansdell, C P; Lasiuk, B; Laue, F; Lauret, J; Lebedev, A; Lednický, R; Leontiev, V M; LeVine, M J; Li, C; Li, Q; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, L; Liu, Z; Liu, Q J; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; Lopez-Noriega, M; Love, W A; Ludlam, T; Lynn, D; Ma, J; Ma, Y G; Magestro, D; Mahajan, S; Mangotra, L K; Mahapatra, D P; Majka, R; Manweiler, R; Margetis, S; Markert, C; Martin, L; Marx, J; Matis, H S; Matulenko, Yu A; McShane, T S; Meissner, F; Melnick, Yu; Meschanin, A; Messer, M; Miller, M L; Milosevich, Z; Minaev, N G; Mironov, C; Mishra, D; Mitchell, J; Mohanty, B; Molnar, L; Moore, C F; Mora-Corral, M J; Morozov, V; de Moura, M M; Munhoz, M G; Nandi, B K; Nayak, S K; Nayak, T K; Nelson, J M; Nevski, P; Nikitin, V A; Nogach, L V; Norman, B; Nurushev, S B; Odyniec, G; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Paic, G; Pandey, S U; Pal, S K; Panebratsev, Y; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Perevoztchikov, V; Peryt, W; Petrov, V A; Phatak, S C; Picha, R; Planinic, M; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M; Potrebenikova, E; Potukuchi, B V K S; Prindle, D; Pruneau, C; Putschke, J; Rai, G; Rakness, G; Raniwala, R; Raniwala, S; Ravel, O; Ray, R L; Razin, S V; Reichhold, D; Reid, J G; Renault, G; Retiere, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Ruan, L J; Rykov, V; Sahoo, R; Sakrejda, I; Salur, S; Sandweiss, J; Savin, I; Schambach, J; Scharenberg, R P; Schmitz, N; Schroeder, L S; Schweda, K; Seger, J; Seliverstov, D; Seyboth, P; Shahaliev, E; Shao, M; Sharma, M; Shestermanov, K E; Shimanskii, S S; Singaraju, R N; Simon, F; Skoro, G; Smirnov, N; Snellings, R; Sood, G; Sorensen, P; Sowinski, J; Spinka, H M; Srivastava, B; Stanislaus, S; Stock, R; Stolpovsky, A; Strikhanov, M; Stringfellow, B; Struck, C; Suaide, A A P; Sugarbaker, E; Suire, C; Sumbera, M; Surrow, B; Symons, T J M; Szanto de Toledo, A; Szarwas, P; Tai, A; Takahashi, J; Tang, A H; Thein, D; Thomas, J H; Tikhomirov, V; Tokarev, M; Tonjes, M B; Trainor, T A; Trentalange, S; Tribble, R E; Trivedi, M D; Trofimov, V; Tsai, O; Ullrich, T; Underwood, D G; Van Buren, G; VanderMolen, A M; Vasiliev, A N; Vasiliev, M; Vigdor, S E; Viyogi, Y P; Voloshin, S A; Waggoner, W; Wang, F; Wang, G; Wang, X L; Wang, Z M; Ward, H; Watson, J W; Wells, R; Westfall, G D; Whitten, C; Wieman, H; Willson, R; Wissink, S W; Witt, R; Wood, J; Wu, J; Xu, N; Xu, Z; Xu, Z Z; Yakutin, A E; Yamamoto, E; Yang, J; Yepes, P; Yurevich, V I; Zanevski, Y V; Zborovský, I; Zhang, H; Zhang, H Y; Zhang, W M; Zhang, Z P; Zołnierczuk, P A; Zoulkarneev, R; Zoulkarneeva, J; Zubarev, A N

    2003-08-15

    We report measurements of single-particle inclusive spectra and two-particle azimuthal distributions of charged hadrons at high transverse momentum (high p(T)) in minimum bias and central d+Au collisions at sqrt[s(NN)]=200 GeV. The inclusive yield is enhanced in d+Au collisions relative to binary-scaled p+p collisions, while the two-particle azimuthal distributions are very similar to those observed in p+p collisions. These results demonstrate that the strong suppression of the inclusive yield and back-to-back correlations at high p(T) previously observed in central Au+Au collisions are due to final-state interactions with the dense medium generated in such collisions.

  4. Use of integral experiments for the assessment of a new 235U IRSN-CEA evaluation

    NASA Astrophysics Data System (ADS)

    Ichou, Raphaëlle; Leclaire, Nicolas; Leal, Luiz; Haeck, Wim; Morillon, Benjamin; Romain, Pascal; Duarte, Helder

    2017-09-01

    The Working Party on International Nuclear Data Evaluation Co-operation (WPEC) subgroup 29 (SG 29) was established to investigate an issue with the 235U capture cross-section in the energy range from 0.1 to 2.25 keV, due to a possible overestimation of 10% or more. To improve the 235U capture crosssection, a new 235U evaluation has been proposed by the Institut de Radioprotection et de Sûreté Nucléaire (IRSN) and the CEA, mainly based on new time-of-flight 235U capture cross-section measurements and recent fission cross-section measurements performed at the n_TOF facility from CERN. IRSN and CEA Cadarache were in charge of the thermal to 2.25 keV energy range, whereas the CEA DIF was responsible of the high energy region. Integral experiments showing a strong 235U sensitivity are used to assess the new evaluation, using Monte-Carlo methods. The keff calculations were performed with the 5.D.1 beta version of the MORET 5 code, using the JEFF-3.2 library and the new 235U evaluation, as well as the JEFF-3.3T1 library in which the new 235U has been included. The benchmark selection allowed highlighting a significant improvement on keff due to the new 235U evaluation. The results of this data testing are presented here.

  5. Flow in Au+Au collisions at RHIC

    NASA Astrophysics Data System (ADS)

    Belt Tonjes, Marguerite; the PHOBOS Collaboration; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tang, J.-L.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wolfs, F. L. H.; Wosiek, B.; Wozniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2004-08-01

    The study of flow can provide information on the initial state dynamics and the degree of equilibration attained in heavy-ion collisions. This contribution presents results for both elliptic and directed flow as determined from data recorded by the PHOBOS experiment in Au+Au runs at RHIC at \\sqrt{sNN} = 19.6, 130 and 200 GeV. The PHOBOS detector provides a unique coverage in pseudorapidity for measuring flow at RHIC. The systematic dependence of flow on pseudorapidity, transverse momentum, centrality and energy is discussed.

  6. Flow in Au+Au collisions at RHIC

    NASA Astrophysics Data System (ADS)

    Belt Tonjes, Marguerite; PHOBOS Collaboration; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Holynski, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tang, J.-L.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wolfs, F. L. H.; Wosiek, B.; Wozniak, K.; Wuosmaa, A. H.; Wyslouch, B.

    2004-08-01

    The study of flow can provide information on the initial state dynamics and the degree of equilibration attained in heavy-ion collisions. This contribution presents results for both elliptic and directed flow as determined from data recorded by the PHOBOS experiment in Au+Au runs at RHIC at \\sqrt{s_{{\\rm NN}}} = 19.6, 130 and 200 GeV. The PHOBOS detector provides a unique coverage in pseudorapidity for measuring flow at RHIC. The systematic dependence of flow on pseudorapidity, transverse momentum, centrality and energy is discussed.

  7. Nanoporous Au structures by dealloying Au/Ag thermal- or laser-dewetted bilayers on surfaces

    NASA Astrophysics Data System (ADS)

    Ruffino, F.; Torrisi, V.; Grillo, R.; Cacciato, G.; Zimbone, M.; Piccitto, G.; Grimaldi, M. G.

    2017-03-01

    Nanoporous Au attracts great technological interest and it is a promising candidate for optical and electrochemical sensors. In addition to nanoporous Au leafs and films, recently, interest was focused on nanoporous Au micro- and nano-structures on surfaces. In this work we report on the study of the characteristics of nanoporous Au structures produced on surfaces. We developed the following procedures to fabricate the nanoporous Au structures: we deposited thin Au/Ag bilayers on SiO2 or FTO (fluorine-doped tin oxide) substrates with thickness xAu and xAg of the Au and Ag layers; we induced the alloying and dewetting processes of the bilayers by furnace annealing processes of the bilayers deposited on SiO2 and by laser irradiations of the bilayers deposited on FTO; the alloying and dewetting processes result in the formation of AuxAgy alloy sub-micron particles being x and y tunable by xAu and xAg. These particles are dealloyed in HNO3 solution to remove the Ag atoms. We obtain, so, nanoporous sub-micron Au particles on the substrates. Analyzing the characteristics of these particles we find that: a) the size and shape of the particles depend on the nature of the dewetting process (solid-state dewetting on SiO2, molten-state dewetting on FTO); b) the porosity fraction of the particles depends on how the alloying process is reached: about 32% of porosity for the particles fabricated by the furnace annealing at 900 °C, about 45% of porosity for the particles fabricated by the laser irradiation at 0.5 J/cm2, in both cases independently on the Ag concentration in the alloy; c) After the dealloying process the mean volume of the Au particles shrinks of about 39%; d) After an annealing at 400 °C the nanoporous Au particles reprise their initial volume while the porosity fraction is reduced. Arguments to justify these behaviors are presented.

  8. Comment on “the ground-state structures of Au10-, Au8Ni and Au9Ni clusters”

    NASA Astrophysics Data System (ADS)

    Zheng, Ben-Xia; Die, Dong; Li, Qian-Qian; Dai, Ming-Liang; Li, Zhi-Qin; Yang, Ji-Xian

    2017-09-01

    The lowest energy structures of Aun+1- and AunNi (n = 2-9) clusters have been researched using the CALYPSO structure searching method in conjunction with the density functional theory. It is found that the most stable structures of Au10-, Au8Ni and Au9Ni clusters reported by Tang et al. [C. M. Tang, X. X. Chen and X. D. Yang, Int. J. Mod. Phys. B 28, 1450138 (2014)] are low-lying isomers. The correct ground states and vibrational spectra are given in this paper.

  9. Inverse Catalysts for CO Oxidation: Enhanced Oxide–Metal Interactions in MgO/Au(111), CeO 2/Au(111), and TiO 2/Au(111)

    DOE PAGES

    Palomino, Robert M.; Gutiérrez, Ramón A.; Liu, Zongyuan; ...

    2017-09-26

    Au(111) does not bind CO and O 2 well. The deposition of small nanoparticles of MgO, CeO 2, and TiO 2 on Au(111) produces excellent catalysts for CO oxidation at room temperature. In an inverse oxide/metal configuration there is a strong enhancement of the oxide–metal interactions, and the inverse catalysts are more active than conventional Au/MgO(001), Au/CeO 2(111), and Au/TiO 2(110) catalysts. An identical trend was seen after comparing the CO oxidation activity of TiO2/Au and Au/TiO 2 powder catalysts. In the model systems, the activity increased following the sequence: MgO/Au(111) < CeO 2/Au(111) < TiO 2/Au(111). Ambient pressure X-raymore » photoelectron spectroscopy (AP-XPS) was used to elucidate the role of the titania–gold interface in inverse TiO 2/Au(111) model catalysts during CO oxidation. Stable surface intermediates such as CO(ads), CO 3 2–(ads), and OH(ads) were identified under reaction conditions. CO 3 2–(ads) and OH(ads) behaved as spectators. The concentration of CO(ad) initially increased and then decreased with increasing TiO 2 coverage, demonstrating a clear role of the Ti–Au interface and the size of the TiO 2 nanostructures in the catalytic process. Overall, our results show an enhancement in the strength of the oxide–metal interactions when working with inverse oxide/metal configurations, a phenomenon that can be utilized for the design of efficient catalysts useful for green and sustainable chemistry.« less

  10. Inverse Catalysts for CO Oxidation: Enhanced Oxide–Metal Interactions in MgO/Au(111), CeO 2/Au(111), and TiO 2/Au(111)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Palomino, Robert M.; Gutiérrez, Ramón A.; Liu, Zongyuan

    Au(111) does not bind CO and O 2 well. The deposition of small nanoparticles of MgO, CeO 2, and TiO 2 on Au(111) produces excellent catalysts for CO oxidation at room temperature. In an inverse oxide/metal configuration there is a strong enhancement of the oxide–metal interactions, and the inverse catalysts are more active than conventional Au/MgO(001), Au/CeO 2(111), and Au/TiO 2(110) catalysts. An identical trend was seen after comparing the CO oxidation activity of TiO2/Au and Au/TiO 2 powder catalysts. In the model systems, the activity increased following the sequence: MgO/Au(111) < CeO 2/Au(111) < TiO 2/Au(111). Ambient pressure X-raymore » photoelectron spectroscopy (AP-XPS) was used to elucidate the role of the titania–gold interface in inverse TiO 2/Au(111) model catalysts during CO oxidation. Stable surface intermediates such as CO(ads), CO 3 2–(ads), and OH(ads) were identified under reaction conditions. CO 3 2–(ads) and OH(ads) behaved as spectators. The concentration of CO(ad) initially increased and then decreased with increasing TiO 2 coverage, demonstrating a clear role of the Ti–Au interface and the size of the TiO 2 nanostructures in the catalytic process. Overall, our results show an enhancement in the strength of the oxide–metal interactions when working with inverse oxide/metal configurations, a phenomenon that can be utilized for the design of efficient catalysts useful for green and sustainable chemistry.« less

  11. Engaging High School Students and Scientists in a Café Scientifique Program

    NASA Astrophysics Data System (ADS)

    Mayhew, M. A.; Hall, M. K.; Foutz, S.

    2010-12-01

    We have created an informal science program that engages high school age youth in exploring science relevant to their lives with researchers working at the cutting edge of science. The program provides scientists a challenging new audience to share their research and enthusiasm for science and science careers. It gives the youth an opportunity to discover how the often-mundane science they are learning in school is used to push the frontiers in science, with exciting applications in the real world. Our program, a youth-led Café Scientifique (cafenm.org), now in its fourth year, has been successful in attracting and retaining youth as well as attracting scientist-presenters. Modeled after the international Café Scientifique program for adults, we combine a social atmosphere with discussion of controversial or current topics to challenge youth to think about how science affects their lives. We feature short presentations with a high degree of interactivity and discussion during which the scientist expert communicates a single important idea or scientific principle. A good speaker will leave the audience with a dilemma or controversy to discuss, and with further opportunities to learn. Encouraging the presenters to interact frequently with the audience allows them to gauge the audience's engagement and knowledge. Alternatively we also host Cafés that offer more hands-on learning experiences, including extracting DNA from plants, building model fuel cell cars, using Google Earth to spy, and deciphering age, gender, ethnicity, and cause of death from human skeletons. Controversial topics are often presented within a scientific, economic, and social or political framework, because science is only part of the solution. A key element of success is in preparing the presenters for the youth audience. Presenters submit their presentation to the program directors for initial review and receive feedback on length, mechanisms for involving the audience, and clarifying or

  12. Influence of Au and TiO2 structures on hydrogen dissociation over TiO2/Au(100)

    NASA Astrophysics Data System (ADS)

    Nakamura, I.; Mantoku, H.; Furukawa, T.; Takahashi, A.; Fujitani, T.

    2012-11-01

    We performed H2-D2 exchange reactions over TiOx/Au(100) and compared the observed reaction kinetics with those reported for TiOx/Au(111) in order to clarify the influence of the Au and TiO2 structures on dissociation of H2 molecules. Low energy electron diffraction observations showed that the TiO2 produced on Au(100) was disordered, in contrast to the comparatively ordered TiO2 structure formed on Au(111). The activation energies and the turnover frequencies for HD formation over TiO2/Au(100) agreed well with those for TiO2/Au(111), clearly indicating that the hydrogen dissociation sites created over TiO2/Au(100) were the perimeter interface between stoichiometric TiO2 and Au, as was previously concluded for TiO2/Au(111). We concluded that the creation of active sites for hydrogen dissociation was independent of the Au and TiO2 structures consisting perimeter interface, and that local bonds that formed between Au and O atoms of stoichiometric TiO2 were essential for the creation of active sites.

  13. [Clinical value of serum TPS, CEA, Pro-GRP and CYFRA21-1 in patients with lung cancer].

    PubMed

    Wang, Jinghui; Shi, Guangli; Zhang, Shucai; Wang, Qunhui; Yang, Xinjie; Li, Xi; Wang, Haiyong; Zhang, Hui; Song, Changxing

    2010-05-01

    Serum tumor markers play important roles in diagnosis, response and prognosis monitoring for lung cancer. The clinical significance of serum level of tissue polypeptide specific antigen (TPS) was investigated in diagnosis, response monitoring and prognosis in patients with lung cancer, compared with carcinoembryonic antigen (CEA), precursor of gastrin-releasing peptide (Pro-GRP) and cytokeratin-19-fragments (CYFRA21-1). Blood samples of eighty-two patients with lung cancer before treatment and some after chemotherapy were measured by ELISA for four tumor markers. Compared with lung benign diseases group and health control group, the positive rates and levels of TPS, CEA and Pro-GRP in patients with lung cancer were higher, with statistically significant difference. TPS in extensive-small cell lung cancer was significant higher than that in limited-small cell lung cancer. The positive rates and levels of TPS, CEA and Pro-GRP in patients after treatment had significant decreases compared with before treatment. TPS was an independent prognostic factor of non-small cell lung cancer. TPS is valuable to diagnosis, response monitoring for patients with lung cancer, moreover, it maybe a useful factor of prognosis of non-small cell lung cancer.

  14. Charged hadron transverse momentum distributions in Au+Au collisions at √sNN=200 GeV

    NASA Astrophysics Data System (ADS)

    Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Lee, J. W.; Manly, S.; McLeod, D.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Veres, G. I.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2004-01-01

    We present transverse momentum distributions of charged hadrons produced in Au+Au collisions at sNN=200 GeV. The spectra were measured for transverse momenta pT from 0.25 to 4.5 GeV/c in a pseudorapidity range of 0.2<η<1.4. The evolution of the spectra is studied as a function of collision centrality, from 65 to 344 participating nucleons. The results are compared to data from proton-antiproton collisions and Au+Au collisions at lower RHIC energies. We find a significant change of the spectral shape between proton-antiproton and semi-peripheral Au+Au collisions. Comparing semi-peripheral to central Au+Au collisions, we find that the yields at high pT exhibit approximate scaling with the number of participating nucleons, rather than scaling with the number of binary collisions.

  15. A comparative theoretical study of the catalytic activities of Au2(-) and AuAg(-) dimers for CO oxidation.

    PubMed

    Liu, Peng; Song, Ke; Zhang, Dongju; Liu, Chengbu

    2012-05-01

    The detailed mechanisms of catalytic CO oxidation over Au(2)(-) and AuAg(-) dimers, which represent the simplest models for monometal Au and bimetallic Au-Ag nanoparticles, have been studied by performing density functional theory calculations. It is found that both Au(2)(-) and AuAg(-) dimers catalyze the reaction according to the similar mono-center Eley-Rideal mechanism. The catalytic reaction is of the multi-channel and multi-step characteristic, which can proceed along four possible pathways via two or three elementary steps. In AuAg(-), the Au site is more active than the Ag site, and the calculated energy barrier values for the rate-determining step of the Au-site catalytic reaction are remarkably smaller than those for both the Ag-site catalytic reaction and the Au(2)(-) catalytic reaction. The better catalytic activity of bimetallic AuAg(-) dimer is attributed to the synergistic effect between Au and Ag atom. The present results provide valuable information for understanding the higher catalytic activity of Au-Ag nanoparticles and nanoalloys for low-temperature CO oxidation than either pure metallic catalyst.

  16. [CEA, CA-19-9 and il-8, sTNFRII and sil-2R in persons at high risk of colorectal cancer].

    PubMed

    Grotowski, Maciej; Wojtuń, Stanisław

    2003-04-01

    The aim of the study was to determine whether elevated concentrations of CEA, CA19-9, IL-8, sTNFRII and sIL-2R occur in persons at high risk of colorectal cancer. A group of 37 persons at high risk of colorectal cancer and 40 healthy subjects (control group) were included into this study. In both groups IL-8, sTNFRII and sIL-2R concentrations were measured by ELISA method (R&D Systems Minneapolis, USA). In the group of persons at high risk of colorectal cancer CEA and CA19-9 concentrations were determined using MEIA kits (Abbott Laboratories, USA). Using the 95th percentiles of the distribution in the control group the upper normal limits of IL-8, sTN-FRII and sIL-2R values were calculated. The cut-off value for CEA was 3 ng/ml and that for CA 19-9 was 37 U/ml. The incidence of elevated concentrations of the studied factors and concentrations of CEA and CA19-9 was compared. The association was assessed of elevated concentrations of the studied factors and CEA and CA19-9 with the results of histological examination of pathological changes in the colon and rectum. In the group of persons at high risk of colorectal cancer only CEA concentration was elevated in 2.7%. The percentages of persons with elevated concentrations of IL-8, sIL-2R and sTNFRII were 29.7, 8.1 and 18.9%, respectively. The percentage of persons with elevated concentrations of IL-8 and sTNFRII was higher in comparison with the percentage of persons with elevated concentrations of CEA and CA19-9 (p < 0.05). Pathological lesions in the colon and rectum were detected in 16 persons (43.2%). High-grade dysplasia was detected in 11 cases. Elevated concentration of IL-8 always accompanied high-grade dysplasia in ulcerative colitis. The concentrations of IL-8 were significantly higher in high-grade dysplasia (23.7 pg/ml, SD +/- 7.53) than in cases of its absence (18.9 pg/ml, SD +/- 3.53) (p < 0.05). The obtained results of preliminary studies with IL-8 in persons at high risk of colorectal cancer require a

  17. The diagnostic value of serum tumor markers CEA, CA19-9, CA125, CA15-3, and TPS in metastatic breast cancer.

    PubMed

    Wang, Weigang; Xu, Xiaoqin; Tian, Baoguo; Wang, Yan; Du, Lili; Sun, Ting; Shi, Yanchun; Zhao, Xianwen; Jing, Jiexian

    2017-07-01

    This study aims to understand the diagnostic value of serum tumor markers carcinoembryonic antigen (CEA), cancer antigen 19-9 (CA19-9), cancer antigen 125 (CA125), cancer antigen 15-3 (CA15-3), and tissue polypeptide-specific antigen (TPS) in metastatic breast cancer (MBC). A total of 164 metastatic breast cancer patients in Shanxi Cancer Hospital were recruited between February 2016 and July 2016. 200 breast cancer patients without metastasis in the same period were randomly selected as the control group. The general characteristics, immunohistochemical, and pathological results were investigated between the two groups, and tumor markers were determined. There were statistical differences in the concentration and the positive rates of CEA, CA19-9, CA125, CA15-3, and TPS between the MBC and control group (P<0.05). The highest sensitivity was in CEA and the highest specificity was in CA125 for the diagnosis of MBC when using a single tumor marker at 56.7% and 97.0%, respectively. In addition, two tumor markers were used for the diagnosis of MBC and the CEA and TPS combination had the highest diagnostic sensitivity with 78.7%, while the CA15-3 and CA125 combination had the highest specificity of 91.5%. Analysis of tumor markers of 164 MBC found that there were statistical differences in the positive rates of CEA and CA15-3 between bone metastases and other metastases (χ 2 =6.00, P=0.014; χ 2 =7.32, P=0.007, respectively). The sensitivity and specificity values of the CEA and CA15-3 combination in the diagnosis of bone metastases were 77.1% and 45.8%, respectively. The positive rate of TPS in the lung metastases group was lower than in other metastases (χ 2 =8.06, P=0.005).There were significant differences in the positive rates of CA15-3 and TPS between liver metastases and other metastases (χ 2 =15.42, P<0.001; χ 2 =9.72, P=0.002, respectively). The sensitivity and specificity of the CA15-3 and TPS combination in the diagnosis of liver metastases were 92.3% and

  18. Toward hybrid Au nanorods @ M (Au, Ag, Pd and Pt) core-shell heterostructures for ultrasensitive SERS probes

    NASA Astrophysics Data System (ADS)

    Xie, Xiaobin; Gao, Guanhui; Kang, Shendong; Lei, Yanhua; Pan, Zhengyin; Shibayama, Tamaki; Cai, Lintao

    2017-06-01

    Being able to precisely control the morphologies of noble metallic nanostructures is of essential significance for promoting the surface-enhanced Raman scattering (SERS) effect. Herein, we demonstrate an overgrowth strategy for synthesizing Au @ M (M = Au, Ag, Pd, Pt) core-shell heterogeneous nanocrystals with an orientated structural evolution and highly improved properties by using Au nanorods as seeds. With the same reaction condition system applied, we obtain four well-designed heterostructures with diverse shapes, including Au concave nanocuboids (Au CNs), Au @ Ag crystalizing face central cube nanopeanuts, Au @ Pd porous nanocuboids and Au @ Pt nanotrepangs. Subsequently, the exact overgrowth mechanism of the above heterostructural building blocks is further analysed via the systematic optimiziation of a series of fabrications. Remarkably, the well-defined Au CNs and Au @ Ag nanopeanuts both exhibit highly promoted SERS activity. We expect to be able to supply a facile strategy for the fabrication of multimetallic heterogeneous nanostructures, exploring the high SERS effect and catalytic activities.

  19. Chiral Magnetic Effect Search in p(d)+Au, Au+Au Collisions at RHIC

    NASA Astrophysics Data System (ADS)

    Zhao, Jie

    The chiral magnetic effect (CME) refers to charge separation along a strong magnetic field of single-handed quarks, caused by interactions with topological gluon fields from QCD vacuum fluctuations. A major background of CME measurements in heavy-ion collisions comes from resonance decays coupled with elliptical flow anisotropy. These proceedings present two new studies from STAR to shed further light on the background issue: (1) small system p+Au and d+Au collisions where the CME signal is not expected, and (2) pair invariant mass dependence where resonance peaks can be identified.

  20. Enhanced power generation and energy conversion of sewage sludge by CEA-microbial fuel cells.

    PubMed

    Abourached, Carole; Lesnik, Keaton Larson; Liu, Hong

    2014-08-01

    The production of methane from sewage sludge through the use of anaerobic digestion has been able to effectively offset energy costs for wastewater treatment. However, significant energy reserves are left unrecovered and effluent standards are not met necessitating secondary processes such as aeration. In the current study a novel cloth-electrode assembly microbial fuel cell (CEA-MFC) was used to generate electricity from sewage sludge. Fermentation pretreatment of the sludge effectively increased the COD of the supernatant and improved reactor performance. Using the CEA-MFC design, a maximum power density of 1200 mW m(-2) was reached after a fermentation pre-treatment time of 96 h. This power density represents a 275% increase over those previously observed in MFC systems. Results indicate continued improvements are possible and MFCs may be a viable modification to existing wastewater treatment infrastructure. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Enhanced middle-infrared light transmission through Au/SiO(x)N(y)/Au aperture arrays.

    PubMed

    Xiao, Gongli; Yao, Xiang; Ji, Xinming; Zhou, Jia; Bao, Zongming; Huang, Yiping

    2011-12-01

    The enhanced middle-infrared light transmission through Au/SiO(x)N(y)/Au aperture arrays by changing the refractive index and the thickness of a dielectric layer was studied experimentally. The results indicated that the transmission spectra was highly dependent on the refractive index and the thickness of SiO(x)N(y). We found that the transmission peaks redshifted regularly along with the refractive index from 1.6 to 1.8, owing to the role of surface plasmon polaritons (SPP) coupling in the Au/SiO(x)N(y)/Au cascaded metallic structure. Simultaneously, a higher transmission efficiency and narrower transmission peak was obtained in Au/SiO2.1N0.3/Au cascaded metallic structure with small refractive index (1.6) than in Au/SiO0.6N1/Au cascaded metallic structure with large refractive index (1.8). When the thickness of SiO(x)N(y) changes from 0.2 to 0.4 microm, the shape of transmission spectra exhibits a large change. It was found that a higher transmission efficiency and narrower transmission peak was obtained in Au/SiO(x)N(y)/Au cascaded metallic structure with a thin dielectric film (0.2 microm), with the increase of SiO(x)N(y) film's thickness, the transmission peak gradually widened and disappeared finally. This effect is useful in applications of biochemical sensing and tunable integrated plasmonic devices in the middle-infrared region.

  2. Largely enhanced photocatalytic activity of Au/XS2/Au (X = Re, Mo) antenna-reactor hybrids: charge and energy transfer.

    PubMed

    Chen, Kai; Ding, Si-Jing; Luo, Zhi-Jun; Pan, Gui-Ming; Wang, Jia-Hong; Liu, Jia; Zhou, Li; Wang, Qu-Quan

    2018-02-22

    An antenna-reactor hybrid coupling plasmonic antenna with catalytic nanoparticles is a new strategy to optimize photocatalytic activity. Herein, we have rationally proposed a Au/XS 2 /Au (X = Re, Mo) antenna reactor, which has a large Au core as the antenna and small satellite Au nanoparticles as the reactor separated by an ultrathin two-dimensional transition-metal dichalcogenide XS 2 shell (∼2.6 nm). Due to efficient charge transfer across the XS 2 shell as well as energy transfer via coupling of the Au antenna and Au reactor, the photocatalytic activity has been largely enhanced: Au/ReS 2 /Au exhibits a 3.59-fold enhancement, whereas Au/MoS 2 /Au exhibits a 2.66-fold enhancement as compared to that of the sum of the three individual components. The different enhancement in the Au/ReS 2 /Au and Au/MoS 2 /Au antenna-reactor hybrid is related to the competition and cooperation of charge and energy transfer. These results indicate the great potential of the Au/XS 2 /Au antenna-reactor hybrid for the development of highly efficient plasmonic photocatalysts.

  3. On the nature of L1{sub 0} ordering in equiatomic AuNi and AuCu thin films grown on Au(001)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dynna, M.; Marty, A.; Gilles, B.

    1997-01-01

    The L1{sub 0} ordering of thin epitaxial films having a (001) surface normal subject to elastic constraints imposed by a similarly oriented substrate has been investigated both experimentally and theoretically. Thin AuNi films grown by MBE at room temperature on Au(001) by means of the alternating deposition of Au and Ni are found to possess a L1{sub 0} structure free of periodic antiphase boundaries when growth is controlled in such a way as to ensure that the quantity of Au or Ni deposited is almost exactly equal to one monolayer. If such control is not exercised during growth, a structuremore » having periodic antiphase boundaries is formed. This behavior stands in contrast to that of AuCu during room temperature MBE growth on Au(001), where a strongly ordered L2{sub 0} structure free of antiphase boundaries is formed even on the codeposition of Au and Cu. The effect of elastic constraints on the state of order in an alloy film which undergoes an L2{sub 0} order-disorder transition is examined as a function of temperature, lattice mismatch, and film thickness within the context of a model which allows for the introduction of dislocations in order to relieve misfit strain. Calculations are performed in detail for the case of AuCu, where particular attention is paid to the coupling between film thickness, the number of misfit dislocations present at equilibrium, and the state of order.« less

  4. [Clinical and prognostic significance of preoperative serum CA153, CEA and TPS levels in patients with primary breast cancer].

    PubMed

    Chen, Yan; Zheng, Yu-hong; Lin, Ying-ying; Hu, Min-hua; Chen, Yan-song

    2011-11-01

    To investigate the clinical and prognostic values of preoperative serum CA153, CEA and TPS levels in patients with primary breast cancer. A total of 386 hospitalized patients with stage I ∼ IV breast cancer from Nov 1998 to Feb 2009 were followed up, and their clinicopathological data were analyzed retrospectively to determine the factors affecting their prognosis. First, preoperative serum CA153 expression level was significantly associated with the age of onset and tumor size (P < 0.05), the expression of serum CEA was correlated with tumor size (P < 0.05), and the expression of serum tissue polypeptide specific antigen (TPS) was correlated with tumor size and lymph node metastases (P < 0.05). Second, the overall survival was significantly shorter among patients with elevated serum CA153, CEA or TPS, respectively (P < 0.05 for overall). Finally, multivariate Cox regression analysis indicated that estrogen receptor status (ER) and elevated preoperative values of CA 153 are independent prognostic factors for overall survival (P < 0.05), and CA 153 is a risk factor but estrogen receptor status is a protective factor for overall survival. Higher preoperative expression of serum CA153, CEA or TPS is closely correlated with clinicopathological characteristics and overall survival. The prognosis is poorer in primary breast cancer patients with higher CA15-3 expression level, and pre-treatment CA153 expression level can be used as an independent prognostic parameter in patients with primarily breast cancer.

  5. Electrochemical immunosensor for simultaneous detection of multiplex cancer biomarkers based on graphene nanocomposites.

    PubMed

    Chen, Xia; Jia, Xinle; Han, Jingman; Ma, Jie; Ma, Zhanfang

    2013-12-15

    In this work, a sandwich-format electrochemical immunosensor for simultaneous determination of carcinoembryonic antigen (CEA) and alpha-fetoprotein (AFP) was fabricated using biofunctional carboxyl graphene nanosheets (CGS) as immunosensing probes, which were fabricated by means of immobilization of toluidine blue (TB) and labeled anti-CEA (Ab2,1), Prussian blue (PB) and anti-AFP (Ab2,2) successively on CGS. The capture anti-CEA (Ab1,1) and anti-AFP (Ab1,2) were immobilized onto the chitosan-Au nanoparticles (CHIT-AuNPs) modified electrode through 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxy succinimide (EDC/NHS). Experimental results revealed that this sandwich-type immunoassay enabled simultaneous detection of CEA and AFP with linear range of 0.5-60 ng mL(-1) for both analytes. The detection limit was 0.1 ng mL(-1) for CEA and 0.05 ng mL(-1) for AFP (S/N=3). The assay results of serum samples with the proposed method were in a good agreement with the reference values from the standard ELISA method. And the negligible cross-reactivity between the two analytes allows it to possess potential promise in clinical diagnosis. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Role of Au(NPs) in the enhanced response of Au(NPs)-decorated MWCNT electrochemical biosensor

    PubMed Central

    Mehmood, Shahid; Ciancio, Regina; Carlino, Elvio; Bhatti, Arshad S

    2018-01-01

    Background The combination of Au-metallic-NPs and CNTs are a new class of hybrid nanomaterials for the development of electrochemical biosensor. Concentration of Au(nanoparticles [NPs]) in the electrochemical biosensor is crucial for the efficient charge transfer between the Au-NPs-MWCNTs modified electrode and electrolytic solution. Methods In this work, the charge transfer kinetics in the glassy carbon electrode (GCE) modified with Au(NPs)–multiwalled carbon nanotube (MWCNT) nanohybrid with varied concentrations of Au(NPs) in the range 40–100 nM was studied using electrochemical impedance spectroscopy (EIS). Field emission scanning electron microscopy and transmission electron microscopy confirmed the attachment of Au(NPs) on the surface of MWCNTs. Results The cyclic voltammetry and EIS results showed that the charge transfer mechanism was diffusion controlled and the rate of charge transfer was dependent on the concentration of Au(NPs) in the nanohybrid. The formation of spherical diffusion zone, which was dependent on the concentration of Au(NPs) in nanohybrids, was attributed to result in 3 times the increase in the charge transfer rate ks, 5 times increase in mass transfer, and 5% (9%) increase in Ipa (Ipc) observed in cyclic voltammetry in 80 nM Au(NP) nanohybrid-modified GCE from MWCNT-modified GCE. The work was extended to probe the effect of charge transfer rates at various concentrations of Au(NPs) in the nanohybrid-modified electrodes in the presence of Escherichia coli. The cyclic voltammetry results clearly showed the best results for 80 nM Au(NPs) in nanohybrid electrode. Conclusion The present study suggested that the formation of spherical diffusion zone in nanohybrid-modified electrodes is critical for the enhanced electrochemical biosensing applications. PMID:29713161

  7. Investigation of the thermal annealing effect on electrical properties of Ni/Au, Ni/Mo/Au and Mo/Au Schottky barriers on AlGaN/GaN heterostructures

    NASA Astrophysics Data System (ADS)

    Sleptsov, E. V.; Chernykh, A. V.; Chernykh, S. V.; Dorofeev, A. A.; Gladysheva, N. B.; Kondakov, M. N.; Sleptsova, A. A.; Panichkin, A. V.; Konovalov, M. P.; Didenko, S. I.

    2017-03-01

    Investigation of the thermal annealing effect on Schottky barrier parameters and the leakage current of Ni/Au, Ni/Mo/Au and Mo/Au Schottky barriers on AlGaN/GaN heterostructures has been performed. Improvement of Schottky barrier parameters after annealing of the investigated metallization schemes was observed. Ni/Au and Mo/Au contacts drastically degrade after annealing at the temperatures higher than 400 °C, whereas the Ni/Mo/Au contact exhibits excellent parameters after 500 °C annealing (qϕb = 1.00 eV, n = 1.13 и Ileak = 5 μA).

  8. Partager : des technologies de pointe au service de la société

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    None

    2011-02-14

    Médecine, climatologie, métrologie et informatique, les techniques utilisées par le LHC trouvent déjà des répercussions dans d’autres domaines scientifiques. Utilisant des techniques inédites, la physique des particules en fait bénéficier la société toute entière.

  9. [Diagnostic values of type III Procollagen N-terminal peptide and combination assay of type III procollagen N-terminal peptide with CEA and CA 19-9 in gastric cancer].

    PubMed

    Akazawa, S; Harada, A; Futatsuki, K

    1984-07-01

    It is known that interstitial collagens are initially synthesized as precursors (procollagen), which possess extra peptide segments at both ends of the molecules. The authors attempted to detect the aminoterminal peptide of type III procollagen (type III-N-peptide) and also to measure the carcinoembryonic antigen (CEA) and carbohydrate antigen (CA 19-9) together in sera of patients with gastric cancer. The results showed that: (1) mean serum levels and positive ratios of the type III-N-peptide increased as the clinical stage of the patients with gastric cancer advanced; (2) serum levels of the type III-N-peptide were not correlated either with those of CEA or CA 19-9; (3) positive ratios of type III-N-peptide, CEA and CA 19-9 were 51.7%, 44.8% and 48.3%, respectively: (4) positive ratio in combination of the type III-N-peptide with CEA was 69.3% and that in combination of the type III-N-peptide with CEA and CA 19-9 was 72.4%. These results suggest that type III-N-peptide is available for diagnosis of gastric cancer and, that the combination assay of type III-N-peptide with CEA and CA 19-9 is more effective than a single assay for diagnosis.

  10. Slab melting and the origin of gold in Au and Au-Cu deposits: geochemical clues from recent adakites.

    NASA Astrophysics Data System (ADS)

    Polve, M.; Maury, R.; Joron, J. L.

    2003-04-01

    Understanding the genetic processes responsible for the common occurrence of Au and Au-Cu deposits in subduction environments is a fairly "hot" question nowadays, as it is clear that most subduction-related magmatic rocks are barren. Studies of space and time relationships between magmatic intrusions, hydrothermal episodes and Au deposits have shown that, very often, Au deposits are associated with adakitic intrusions (Thieblemont et al, 1997, Sajona and Maury, 1998). Adakites are here understood as being generated by melting of the subducting oceanic crust. This study aims to check wether or not magmas derived from melted oceanic crust do contain significantly more Au than regular calc-alkaline magmas by measuring directly Au concentrations in fresh (and barren) adakites and equivalent calc-alkaline andesites. There is a lack of reliable data on Au content in unaltered adakites and andesites, because Au analyses are generally done on hydrothermalized rocks in connection with Au deposits and also because old measurements may give overestimated Au contents, due to technical limitations. Therefore we compiled recent literature data on gold contents of fresh calc-alkaline rocks, and measured Au on a selection of 40 well studied and dated adakites from different localities (Philippines, Baja California). Analyses have been performed either by INAA or by ICP-MS after Au extraction with aqua regia, following the method described by Terashima (1988). Preliminary results show that, for equivalent Si02 contents, adakites are systematically enriched in Au compared to regular dacites, even if regional trends also exist. Moreover, Au seems to behave as an incompatible element in adakitic magmas, whereas in calc-alkaline dacites it is controlled by sulfide crystallization. Our data suggest that, not excluding any other processes related to the hydrothermal phase in the deposit generation, adakites may indeed represent the source of Au, a possible explanation for the adakite-Au

  11. Characteristics of Au Migration and Concentration Distributions in Au-Doped HgCdTe LPE Materials

    NASA Astrophysics Data System (ADS)

    Sun, Quanzhi; Yang, Jianrong; Wei, Yanfeng; Zhang, Juan; Sun, Ruiyun

    2015-08-01

    Annealing techniques and secondary ion mass spectrometry have been used to study the characteristics of Au migration and concentration distributions in HgCdTe materials grown by liquid phase epitaxy. Secondary ion mass spectrometry measurements showed that Au concentrations had obvious positive correlations with Hg-vacancy concentration and dislocation density of the materials. Au atoms migrate toward regions of high Hg-vacancy concentration or move away from these regions when the Hg-vacancy concentration decreases during annealing. The phenomenon can be explained by defect chemical equilibrium theory if Au atoms have a very large migration velocity compared with Hg vacancies. Au atoms will also migrate toward regions of high dislocation density, leading to a peak concentration in the inter-diffusion region of HgCdTe materials near the substrate. By use of an Hg and Te-rich annealing technique, different concentration distributions of both Au atoms and Hg vacancies in HgCdTe materials were obtained, indicating that Au-doped HgCdTe materials can be designed and prepared to satisfy the requirements of HgCdTe devices.

  12. Local structure and X-ray magnetic circular dichroism of Au in Au-Co nanoalloys

    NASA Astrophysics Data System (ADS)

    Maurizio, C.; Michieli, N.; Kalinic, B.; Mattarello, V.; Bello, V.; Wilhelm, F.; Ollefs, K.; Mattei, G.

    2018-03-01

    Coupling a plasmonic metal with a magnetic one in thin films and nanostructures is very interesting for the emerging field of magnetoplasmonics. In particular, coupling through alloying is a promising strategy to induce a magnetic moment on the plasmonic metal atoms, in a way that is intimately related to the local structure of the (metastable) alloy material. In this framework, Au:Co bimetallic films have been produced via magnetron co-sputtering deposition. X-ray absorption spectroscopy (XAS) at both Au- and Co-edges clearly indicates the formation of a full-metallic layer composed for the major part of a binary AuxCo1-x alloy, with x = 0.7-0.8. XAS and transmission electron microscopy analyses suggest the presence of a minor fraction of segregated metals. X-ray magnetic circular dichroism (XMCD) analysis at Au L2,3 edges detected a net magnetic moment of Au atoms (μ = 0.06 μB), significantly larger (≈3.5 times) that the one for Au-capped Co nanoclusters and comparable to the one for a Co-rich Au/Co multilayer, despite the 4 times larger concentration of Co with respect to the present case. This Au-Co magnetic coupling is favored by a high degree of mixing of the two metals in the alloy.

  13. Gold(I) Complexes with N-Donor Ligands. 2.(1) Reactions of Ammonium Salts with [Au(acac-kappaC(2))(PR(3))] To Give [Au(NH(3))L](+), [(AuL)(2)(&mgr;(2)-NH(2))](+), [(AuL)(4)(&mgr;(4)-N)](+), or [(AuL)(3)(&mgr;(3)-O)](+). A New and Facile Synthesis of [Au(NH(3))(2)](+) Salts. Crystal Structure of [{AuP(C(6)H(4)OMe-4)(3)}(3)(&mgr;(3)-O)]CF(3)SO(3).

    PubMed

    Vicente, José; Chicote, María-Teresa; Guerrero, Rita; Jones, Peter G.; Ramírez De Arellano, M. Carmen

    1997-09-24

    The complexes [Au(acac-kappaC(2))(PR(3))] (acac = acetylacetonate, R = Ph, C(6)H(4)OMe-4) react with (NH(4))ClO(4) to give amminegold(I), [Au(NH(3))(PR(3))]ClO(4), amidogold(I), [(AuPR(3))(2)(&mgr;(2)-NH(2))]ClO(4), or nitridogold(I), [(AuPR(3))(4)(&mgr;(4)-N)]ClO(4), complexes, depending on the reaction conditions. Similarly, [Au(acac-kappaC(2))(PPh(3))] reacts with (NH(3)R')OTf (OTf = CF(3)SO(3)) (1:1) or with [H(3)N(CH(2))(2)NH(2)]OTf (1:1) to give (amine)gold(I) complexes [Au(NH(2)R')(PPh(3))]OTf (R' = Me, C(6)H(4)NO(2)-4) or [(AuPPh(3))(2){&mgr;(2)-H(2)N(CH(2))(2)NH(2)}](OTf)(2), respectively. The ammonium salts (NH(2)R'(2))OTf (R' = Et, Ph) react with [Au(acac-kappaC(2))(PR(3))] (R = Ph, C(6)H(4)OMe-4) (1:2) to give, after hydrolysis, the oxonium salts [(AuPR(3))(3)(&mgr;(3)-O)]OTf (R = Ph, C(6)H(4)OMe-4). When NH(3) is bubbled through a solution of [AuCl(tht)] (tht = tetrahydrothiophene), the complex [Au(NH(3))(2)]Cl precipitates. Addition of [Au(NH(3))(2)]Cl to a solution of AgClO(4) or TlOTf leads to the isolation of [Au(NH(3))(2)]ClO(4) or [Au(NH(3))(2)]OTf, respectively. The crystal structure of [(AuPR(3))(3)(&mgr;(3)-O)]OTf.Me(2)CO (R = C(6)H(4)OMe-4) has been determined: triclinic, space group P&onemacr;, a = 14.884(3) Å, b = 15.828(3) Å, c = 16.061(3) Å, alpha = 83.39(3) degrees, beta = 86.28(3) degrees, gamma = 65.54(3) degrees, R1 (wR2) = 0.0370 (0.0788). The [(AuPR(3))(3)(&mgr;(3)-O)](+) cation shows an essentially trigonal pyramidal array of three gold atoms and one oxygen atom with O-Au-P bond angles of ca. 175 degrees and Au.Au contacts in the range 2.9585(7)-3.0505(14) Å. These cations are linked into centrosymmetric dimers through two short Au.Au [2.9585(7), 3.0919(9) Å] contacts. The gold atoms of the dimer form a six-membered ring with a chair conformation.

  14. Development of amperometric lysine biosensors based on Au nanoparticles/multiwalled carbon nanotubes/polymers modified Au electrodes.

    PubMed

    Chauhan, Nidhi; Singh, Anamika; Narang, Jagriti; Dahiya, Swati; Pundir, C S

    2012-11-07

    The construction of two amperometric l-lysine biosensors is described in this study. The construction comprises the covalent immobilization of lysine oxidase (LOx) onto nanocomposite composed of gold nanoparticles (AuNPs) and carboxylated multiwalled carbon nanotubes (c-MWCNT), decorated on (i) polyaniline (PANI) and (ii) poly 1,2 diaminobenzene (DAB), electrodeposited on Au electrodes. The biosensors were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) and electrochemical impedance spectroscopy (EIS) studies. The optimum response (current) was observed within 2 s at pH 7.0 and 25 °C for LOx/AuNPs/c-MWCNT/PANI/Au, and 4 s at pH 7.0 and 30 °C for LOx/AuNPs/c-MWCNT/DAB/Au electrodes. There was a linear relationship between current and lysine concentration ranging from 5.0 to 600 μM for LOx/AuNPs/c-MWCNT/PANI/Au with a detection limit of 5.0 μM, and 20 to 600 μM for the LOx/AuNPs/c-MWCNT/DAB/Au electrode with a detection limit of 20 μM. The PANI modified electrode was in good agreement with the standard HPLC method, with a better correlation (r = 0.992) compared to the DAB modified electrode (r = 0.986). These observations revealed that the PANI modified Au electrode was better than the DAB modified electrode, and hence it was employed for the determination of lysine in milk, pharmaceutical tablets and sera. The PANI modified electrode showed a half life of 120 days, compared to that of 90 days for the DAB modified electrode, after their 100 uses, when stored at 4 °C.

  15. Synthesis of Au38(SCH2CH2Ph)24, Au36(SPh-tBu)24, and Au30(S-tBu)18 Nanomolecules from a Common Precursor Mixture.

    PubMed

    Rambukwella, Milan; Dass, Amala

    2017-10-17

    Phenylethanethiol protected nanomolecules such as Au 25 , Au 38 , and Au 144 are widely studied by a broad range of scientists in the community, owing primarily to the availability of simple synthetic protocols. However, synthetic methods are not available for other ligands, such as aromatic thiol and bulky ligands, impeding progress. Here we report the facile synthesis of three distinct nanomolecules, Au 38 (SCH 2 CH 2 Ph) 24 , Au 36 (SPh-tBu) 24 , and Au 30 (S-tBu) 18 , exclusively, starting from a common Au n (glutathione) m (where n and m are number of gold atoms and glutathiolate ligands) starting material upon reaction with HSCH 2 CH 2 Ph, HSPh-tBu, and HStBu, respectively. The systematic synthetic approach involves two steps: (i) synthesis of kinetically controlled Au n (glutathione) m crude nanocluster mixture with 1:4 gold to thiol molar ratio and (ii) thermochemical treatment of the purified nanocluster mixture with excess thiols to obtain thermodynamically stable nanomolecules. Thermochemical reactions with physicochemically different ligands formed highly monodispersed, exclusively three different core-size nanomolecules, suggesting a ligand induced core-size conversion and structural transformation. The purpose of this work is to make available a facile and simple synthetic method for the preparation of Au 38 (SCH 2 CH 2 Ph) 24 , Au 36 (SPh-tBu) 24 , and Au 30 (S-tBu) 18 , to nonspecialists and the broader scientific community. The central idea of simple synthetic method was demonstrated with other ligand systems such as cyclopentanethiol (HSC 5 H 9 ), cyclohexanethiol(HSC 6 H 11 ), para-methylbenzenethiol(pMBT), 1-pentanethiol(HSC 5 H 11 ), 1-hexanethiol(HSC 6 H 13 ), where Au 36 (SC 5 H 9 ) 24 , Au 36 (SC 6 H 11 ) 24 , Au 36 (pMBT) 24 , Au 38 (SC 5 H 11 ) 24 , and Au 38 (SC 6 H 13 ) 24 were obtained, respectively.

  16. Photoluminescence from Au nanoparticles embedded in Au:oxide composite films

    NASA Astrophysics Data System (ADS)

    Liao, Hongbo; Wen, Weijia; Wong, George K.

    2006-12-01

    Au:oxide composite multilayer films with Au nanoparticles sandwiched by oxide layers (such as SiO2, ZnO, and TiO2) were prepared in a magnetron sputtering system. Their photoluminescence (PL) spectra were investigated by employing a micro-Raman system in which an Argon laser with a wavelength of 514 nm was used as the pumping light. Distinct PL peaks located at a wavelength range between 590 and 680 nm were observed in most of our samples, with Au particle size varying from several to hundreds of nanometers. It was found that the surface plasmon resonance (SPR) in these composites exerted a strong influence on the position of the PL peaks but had little effect on the PL intensity.

  17. Multiple Nonstoichiometric Phases with Discrete Composition Ranges in the CaAu5−CaAu4Bi−BiAu2 System. A Case Study of the Chemistry of Spinodal Decomposition

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lin, Qisheng; Corbett, John D.

    2010-04-01

    Synthetic explorations in the CaAu{sub 5}-CaAu{sub 4}Bi-BiAu{sub 2} system at 400 C reveal five separate solid solution regions that show three distinct substitution patterns in the CaAu{sub 5} parent: (I) CaAu{sub 4}(Au{sub 1-m}Bi{sub m}) with 0 {le} m {le} 0.15(1), (II) 0.33(1) {le} m {le} 0.64(1), (III) 0.85(4) {le} m {le} 0.90(2); (IV) (Ca{sub 1-r}Au{sub r})Au{sub 4}(Bi{sub 1-s}Au{sub s}) with 0 {le} r {le} 0.39(1) and 0 {le} s {le} 0.12(2); (V) (Ca{sub 1-p-q}Au{sub p}Bi{sub q})Au{sub 4}Bi with 0.09(2) {le} p {le} 0.13(1) and 0.31(2) {le} q {le} 0.72(4). Single crystal X-ray studies establish that all of these phase regionsmore » have common cubic symmetry F{sub 4}3m and that their structures (MgCu{sub 4}Sn-type, an ordered derivative of MgCu{sub 2}) all feature three-dimensional networks of Au{sub 4} tetrahedra, in which the truncated tetrahedra are centered and capped by Ca/Au, Au/Bi, or Ca/Au/Bi mixtures to give 16-atom Friauf polyhedra. TB-LMTO-ASA and -COHP calculations also reveal that direct interactions between Ca-Au and Ca-Bi pairs of atoms are relatively weak and that the Bi-Au interactions in the unstable ideal CaAu{sub 4}Bi are antibonding in character at E{sub F} but that their bonding is optimized at {+-}1 e. Compositions between the five nonstoichiometric phases appear to undergo spinodal decompositions. The last phenomenon has been confirmed by HRTEM, STEM-HAADF, EPMA, and XRD studies of the nominal composition CaAu{sub 4.25}Bi{sub 0.75}. Its DTA analyses suggest that the phases resulting from spinodal decomposition have nearly the same melting point ({approx}807 C), as expected, and that they are interconvertible through peritectic reactions at {approx}717 C.« less

  18. Nanoporous Au: An experimental study on the porosity of dealloyed AuAg leafs

    NASA Astrophysics Data System (ADS)

    Grillo, R.; Torrisi, V.; Ruffino, F.

    2016-12-01

    We present a study on the fraction of porosity for dealloyed nanoporous Au leafs. Nanoporous Au is attracting great scientific interest due to its peculiar plasmonic properties and the high exposed surface (∼10 m2/g). As examples, it was used in prototypes of chemical and biological devices. However, the maximization of the devices sensitivity is subjected to the maximization of the exposed surface by the nanoporous Au, i. e. maximization of the porosity fraction. So, we report on the analyses of the porosity fraction in nanoporous Au leafs as a function of the fabrication process parameters. We dealloyed 60 μm-thick Au23Ag77 at.% leafs and we show that: a) for dealloying time till to 6 h, only a 450 nm-thick surface layer of the leafs assumes a nanoporous structure with a porosity fraction of 32%. For a dealloying time of 20 h the leafs result fragmented in small black pieces with a porosity fraction increased to 60%. b) After 600 °C-30 minutes annealing of the previous samples, the nanopores disappear due to the Au/residual Ag inter-diffusion. c) After a second dealloying process on the previously annealed samples, the surface nanoporous structure is, again, obtained with the porosity fraction increased to 50%.

  19. The effect of Au amount on size uniformity of self-assembled Au nanoparticles

    NASA Astrophysics Data System (ADS)

    Chen, S.-H.; Wang, D.-C.; Chen, G.-Y.; Chen, K.-Y.

    2008-03-01

    The self-assembled fabrication of nanostructure, a dreaming approach in the area of fabrication engineering, is the ultimate goal of this research. A finding was proved through previous research that the size of the self-assembled gold nanoparticles could be controlled with the mole ratio between AuCl4- and thiol. In this study, the moles of Au were fixed, only the moles of thiol were adjusted. Five different mole ratios of Au/S with their effect on size uniformity were investigated. The mole ratios were 1:1/16, 1:1/8, 1:1, 1:8, 1:16, respectively. The size distributions of the gold nanoparticles were analyzed by Mac-View analysis software. HR-TEM was used to derive images of self-assembled gold nanoparticles. The result reached was also the higher the mole ratio between AuCl4- and thiol the bigger the self-assembled gold nanoparticles. Under the condition of moles of Au fixed, the most homogeneous nanoparticles in size distribution derived with the mole ratio of 1:1/8 between AuCl4- and thiol. The obtained nanoparticles could be used, for example, in uniform surface nanofabrication, leading to the fabrication of ordered array of quantum dots.

  20. Colloidal Au and Au-alloy catalysts for direct borohydride fuel cells: Electrocatalysis and fuel cell performance

    NASA Astrophysics Data System (ADS)

    Atwan, Mohammed H.; Macdonald, Charles L. B.; Northwood, Derek O.; Gyenge, Elod L.

    Supported colloidal Au and Au-alloys (Au-Pt and Au-Pd, 1:1 atomic ratio) on Vulcan XC-72 (with 20 wt% metal load) were prepared by the Bönneman method. The electrocatalytic activity of the colloidal metals with respect to borohydride electro-oxidation for fuel cell applications was investigated by voltammetry on static and rotating electrodes, chronoamperometry, chronopotentiometry and fuel cell experiments. The fundamental electrochemical techniques showed that alloying Au, a metal that leads to the maximum eight-electron oxidation of BH 4 -, with Pd or Pt, well-known catalysts of dehydrogenation reactions, improved the electrode kinetics of BH 4 - oxidation. Fuel cell experiments corroborated the kinetic studies. Using 5 mg cm -2 colloidal metal load on the anode, it was found that Au-Pt was the most active catalyst giving a cell voltage of 0.47 V at 100 mA cm -2 and 333 K, while under identical conditions the cell voltage using colloidal Au was 0.17 V.

  1. Measurements of charmonium production in p+p, p+Au, and Au+Au collisions at s NN = 200  GeV with the STAR experiment

    DOE PAGES

    Todoroki, Takahito

    2017-09-25

    Here, we present the first results from the STAR MTD of mid-rapidity charmonium measurements via the di-muon decay channel in p+p, p+Au, and Au+Au collisions at √S NN = 200 GeV at RHIC. The inclusive J/Ψ production cross section in p+p collisions can be described by the Non-Relativistic QCD (NRQCD) formalism coupled with the color glass condensate e ective theory (CGC) at low transverse momentum (p T) and next-to-leading order NRQCD at high p T. The nuclear modification factor in p+Au collisions for inclusive J/Ψ is below unity at low p T and consistent with unity at high p T,more » which can be described by calculations including both nuclear PDF and nuclear absorption e ects. The double ratio of inclusive J/Ψ and Ψ(2S) production rates for 0 < p T < 10 GeV/c at mid-rapidity between p+p and p+Au collisions is measured to be 1.37 0.42 0.19. The nuclear modification factor in Au+Au collisions for inclusive J/Ψ shows significant J/Ψ suppression at high p T in central collisions and can be qualitatively described by transport models including dissociation and regeneration contributions.« less

  2. Measurements of charmonium production in p+p, p+Au, and Au+Au collisions at s NN = 200  GeV with the STAR experiment

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Todoroki, Takahito

    Here, we present the first results from the STAR MTD of mid-rapidity charmonium measurements via the di-muon decay channel in p+p, p+Au, and Au+Au collisions at √S NN = 200 GeV at RHIC. The inclusive J/Ψ production cross section in p+p collisions can be described by the Non-Relativistic QCD (NRQCD) formalism coupled with the color glass condensate e ective theory (CGC) at low transverse momentum (p T) and next-to-leading order NRQCD at high p T. The nuclear modification factor in p+Au collisions for inclusive J/Ψ is below unity at low p T and consistent with unity at high p T,more » which can be described by calculations including both nuclear PDF and nuclear absorption e ects. The double ratio of inclusive J/Ψ and Ψ(2S) production rates for 0 < p T < 10 GeV/c at mid-rapidity between p+p and p+Au collisions is measured to be 1.37 0.42 0.19. The nuclear modification factor in Au+Au collisions for inclusive J/Ψ shows significant J/Ψ suppression at high p T in central collisions and can be qualitatively described by transport models including dissociation and regeneration contributions.« less

  3. High-temperature stability of Au/Pd/Cu and Au/Pd(P)/Cu surface finishes

    NASA Astrophysics Data System (ADS)

    Ho, C. E.; Hsieh, W. Z.; Lee, P. T.; Huang, Y. H.; Kuo, T. T.

    2018-03-01

    Thermal reliability of Au/Pd/Cu and Au/Pd(4-6 wt.% P)/Cu trilayers in the isothermal annealing at 180 °C were investigated by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (TOF-SIMS), and transmission electron microscopy (TEM). The pure Pd film possessed a nanocrystalline structure with numerous grain boundaries, thereby facilitating the interdiffusion between Au and Cu. Out-diffusion of Cu through Pd and Au grain boundaries yielded a significant amount of Cu oxides (CuO and Cu2O) over the Au surface and gave rise to void formation in the Cu film. By contrast, the Pd(P) film was amorphous and served as a good diffusion barrier against Cu diffusion. The results of this study indicated that amorphous Pd(P) possessed better oxidation resistance and thermal reliability than crystalline Pd.

  4. Uncommon and Emissive {[Au2(C3H6NS2)2][Au(C3H6NS2)2]2(PF6)2} Mixed Au+ and Au3+ Pseudotetranuclear Crystalline Compound: Synthesis, Structural Characterization, and Optical Properties.

    PubMed

    Langaro, Ana P; Souza, Ana K R; Morassuti, Claudio Y; Lima, Sandro M; Casagrande, Gleison A; Deflon, Victor M; Nunes, Luiz A O; Da Cunha Andrade, Luis H

    2016-11-23

    An uncommon emissive pseudotetranuclear compound, {[Au 2 (C 3 H 6 NS 2 ) 2 ][Au(C 3 H 6 NS 2 ) 2 ] 2 (PF 6 ) 2 }, was synthesized and characterized in terms of its structure and optical properties. The synthesis produced a crystalline compound composed of four gold atoms with two different oxidation states (Au + and Au 3+ ) in the same crystalline structure. The title complex belonged to a triclinic crystalline system involving the centrosymmetric P1̅ space group. X-ray diffractometry and vibrational spectroscopy (infrared, Raman, and SERS) were used for structural characterization of the new crystal. The vibrational spectroscopy techniques supported the X-ray diffraction results and confirmed the presence of bonds including Au-Au and Au-S. Optical characterization performed using UV-vis spectroscopy showed that under ultraviolet excitation, the emissive crystalline complex presented characteristic broad luminescent bands centered at 420 and 670 nm.

  5. Compound formation and superconductivity in Au-Si: X-ray absorption measurements on ion-beam-mixed Au-Si films

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jeon, Y.; Jisrawi, N.; Liang, G.

    Multilayered Au-Si thin films have been deposited with the net compositions ''Au/sub 1-//sub x/Si/sub x/,'' x = 0.29, 0.5, and 0.8. After ion-beam mixing these films exhibited superconductivity in the 0.3--1.2 K range despite the nonsuperconducting character of both Au and Si. Near-edge x-ray absorption spectroscopy (XAS) measurements on the Au L/sub 3/ edge in these films indicate that metastable Au-Si compound formation occurs in these ion-mixed materials. Specifically, the XAS measurements indicate changes in Au 5d-orbital occupancy and changes in the local Au structural environment which are both consistent with local compound formation.

  6. Au plasmonics in a WS{sub 2}-Au-CuInS{sub 2} photocatalyst for significantly enhanced hydrogen generation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cheng, Zhongzhou; School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083; Wang, Zhenxing, E-mail: wangzx@nanoctr.cn, E-mail: hej@nanoctr.cn

    2015-11-30

    Promoting the activities of photocatalysts is still the critical challenge in H{sub 2} generation area. Here, a Au plasmon enhanced photocatalyst of WS{sub 2}-Au-CuInS{sub 2} is developed by inserting Au nanoparticles between WS{sub 2} nanotubes and CuInS{sub 2} (CIS) nanoparticles. Due to the localized surface plasmonic resonance properties from Au nanoparticles, WS{sub 2}-Au-CIS shows the best performance as compared to Au-CIS, CIS, WS{sub 2}-CIS, CIS-Au, WS{sub 2}-Au, and WS{sub 2}-CIS-Au. The surface plasmonic resonance effects dramatically intensify the absorption of visible light and help to inject hot electrons into the semiconductors. Our findings open up an efficient method to optimizemore » the type-II structures for photocatalytic water splitting.« less

  7. Identified particles in Au+Au collisions at S=200 GeV

    NASA Astrophysics Data System (ADS)

    Phobos Collaboration; Wosiek, Barbara; Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2003-03-01

    The yields of identified particles have been measured at RHIC for Au+Au collisions at S=200 GeV using the PHOBOS spectrometer. The ratios of antiparticle to particle yields near mid-rapidity are presented. The first measurements of the invariant yields of charged pions, kaons and protons at very low transverse momenta are also shown.

  8. pH-Induced transformation of ligated Au25 to brighter Au23 nanoclusters.

    PubMed

    Waszkielewicz, Magdalena; Olesiak-Banska, Joanna; Comby-Zerbino, Clothilde; Bertorelle, Franck; Dagany, Xavier; Bansal, Ashu K; Sajjad, Muhammad T; Samuel, Ifor D W; Sanader, Zeljka; Rozycka, Miroslawa; Wojtas, Magdalena; Matczyszyn, Katarzyna; Bonacic-Koutecky, Vlasta; Antoine, Rodolphe; Ozyhar, Andrzej; Samoc, Marek

    2018-05-01

    Thiolate-protected gold nanoclusters have recently attracted considerable attention due to their size-dependent luminescence characterized by a long lifetime and large Stokes shift. However, the optimization of nanocluster properties such as the luminescence quantum yield is still a challenge. We report here the transformation of Au25Capt18 (Capt labels captopril) nanoclusters occurring at low pH and yielding a product with a much increased luminescence quantum yield which we have identified as Au23Capt17. We applied a simple method of treatment with HCl to accomplish this transformation and we characterized the absorption and emission of the newly created ligated nanoclusters as well as their morphology. Based on DFT calculations we show which Au nanocluster size transformations can lead to highly luminescent species such as Au23Capt17.

  9. Measurements of mass-dependent azimuthal anisotropy in central p + Au, d + Au, and He 3 + Au collisions at s N N = 200 GeV

    DOE PAGES

    Adare, A.; Aidala, C.; Ajitanand, N. N.; ...

    2018-06-11

    Here, we present measurements of the transverse-momentum dependence of elliptic flow v 2 for identified pions and (anti)protons at midrapidity (|η| < 0.35), in 0%–5% central p+Au and 3He+Au collisions at √ s NN = 200 GeV. When taken together with previously published measurements in d + Au collisions at √ s NN = 200 GeV, the results cover a broad range of small-collision-system multiplicities and intrinsic initial geometries. We observe a clear mass-dependent splitting of v 2(p T) in d + Au and 3He + Au collisions, just as in large nucleus-nucleus (A + A) collisions, and a smallermore » splitting in p + Au collisions. Both hydrodynamic and transport model calculations successfully describe the data at low p T (< 1.5GeV/c), but fail to describe various features at higher p T. In all systems, the v 2 values follow an approximate quark-number scaling as a function of the hadron transverse kinetic energy per constituent quark (KE T/n q), which was also seen previously in A + A collisions.« less

  10. Measurements of mass-dependent azimuthal anisotropy in central p + Au, d + Au, and He 3 + Au collisions at s N N = 200 GeV

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Adare, A.; Aidala, C.; Ajitanand, N. N.

    Here, we present measurements of the transverse-momentum dependence of elliptic flow v 2 for identified pions and (anti)protons at midrapidity (|η| < 0.35), in 0%–5% central p+Au and 3He+Au collisions at √ s NN = 200 GeV. When taken together with previously published measurements in d + Au collisions at √ s NN = 200 GeV, the results cover a broad range of small-collision-system multiplicities and intrinsic initial geometries. We observe a clear mass-dependent splitting of v 2(p T) in d + Au and 3He + Au collisions, just as in large nucleus-nucleus (A + A) collisions, and a smallermore » splitting in p + Au collisions. Both hydrodynamic and transport model calculations successfully describe the data at low p T (< 1.5GeV/c), but fail to describe various features at higher p T. In all systems, the v 2 values follow an approximate quark-number scaling as a function of the hadron transverse kinetic energy per constituent quark (KE T/n q), which was also seen previously in A + A collisions.« less

  11. Recent HBT results in Au+Au and p+p collisions from PHENIX

    NASA Astrophysics Data System (ADS)

    PHENIX Collaboration; Glenn, Andrew; PHENIX Collaboration

    2009-11-01

    We present Hanbury-Brown Twiss measurements from the PHENIX experiment at RHIC for final results for charged kaon pairs from s=200 GeV Au+Au collisions and preliminary results for charged pion pairs from s=200 GeVp+p collisions. We find that for kaon pairs from Au+Au, each traditional 3D Gaussian radius shows approximately the same linear increase as a function of Npart1/3. An imaging analysis reveals a significant non-Gaussian tail for r≳10 fm. The presence of a tail for kaon pairs demonstrates that similar non-Gaussian tails observed in earlier pion measurements cannot be fully explained by decays of long-lived resonances. The preliminary analysis of pions from s=200 GeV p+p minimum biased collisions show correlations which are well suited to traditional 3D HBT radii extraction via the Bowler-Sinyukov method, and we present R, R, and R as a function of mean transverse pair mass.

  12. {phi} meson production in Au + Au and p + p collisions at {radical}s{sub NN}=200 GeV

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Adams, J.; Adler, C.; Aggarwal, M.M.

    2004-06-01

    We report the STAR measurement of {psi} meson production in Au + Au and p + p collisions at {radical}s{sub NN} = 200 GeV. Using the event mixing technique, the {psi} spectra and yields are obtained at midrapidity for five centrality bins in Au+Au collisions and for non-singly-diffractive p+p collisions. It is found that the {psi} transverse momentum distributions from Au+Au collisions are better fitted with a single-exponential while the p+p spectrum is better described by a double-exponential distribution. The measured nuclear modification factors indicate that {psi} production in central Au+Au collisions is suppressed relative to peripheral collisions when scaledmore » by the number of binary collisions (). The systematics of versus centrality and the constant {psi}/K{sup -} ratio versus beam species, centrality, and collision energy rule out kaon coalescence as the dominant mechanism for {psi} production.« less

  13. Measurements of mass-dependent azimuthal anisotropy in central p + Au, d + Au, and 3He + Au collisions at √{sN N}=200 GeV

    NASA Astrophysics Data System (ADS)

    Adare, A.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Alfred, M.; Andrieux, V.; Apadula, N.; Asano, H.; Azmoun, B.; Babintsev, V.; Bagoly, A.; Bai, M.; Bandara, N. S.; Bannier, B.; Barish, K. N.; Bathe, S.; Bazilevsky, A.; Beaumier, M.; Beckman, S.; Belmont, R.; Berdnikov, A.; Berdnikov, Y.; Blau, D. S.; Boer, M.; Bok, J. S.; Boyle, K.; Brooks, M. L.; Bryslawskyj, J.; Bumazhnov, V.; Campbell, S.; Canoa Roman, V.; Cervantes, R.; Chen, C.-H.; Chi, C. Y.; Chiu, M.; Choi, I. J.; Choi, J. B.; Chujo, T.; Citron, Z.; Connors, M.; Cronin, N.; Csanád, M.; Csörgő, T.; Danley, T. W.; Datta, A.; Daugherity, M. S.; David, G.; Deblasio, K.; Dehmelt, K.; Denisov, A.; Deshpande, A.; Desmond, E. J.; Dion, A.; Diss, P. B.; Dixit, D.; Do, J. H.; Drees, A.; Drees, K. A.; Durham, J. M.; Durum, A.; Enokizono, A.; En'yo, H.; Esumi, S.; Fadem, B.; Fan, W.; Feege, N.; Fields, D. E.; Finger, M.; Finger, M.; Fokin, S. L.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fukuda, Y.; Gal, C.; Gallus, P.; Garg, P.; Ge, H.; Giordano, F.; Glenn, A.; Goto, Y.; Grau, N.; Greene, S. V.; Grosse Perdekamp, M.; Gunji, T.; Guragain, H.; Hachiya, T.; Haggerty, J. S.; Hahn, K. I.; Hamagaki, H.; Hamilton, H. F.; Han, S. Y.; Hanks, J.; Hasegawa, S.; Haseler, T. O. S.; Hashimoto, K.; He, X.; Hemmick, T. K.; Hill, J. C.; Hill, K.; Hodges, A.; Hollis, R. S.; Homma, K.; Hong, B.; Hoshino, T.; Hotvedt, N.; Huang, J.; Huang, S.; Imai, K.; Imrek, J.; Inaba, M.; Iordanova, A.; Isenhower, D.; Ivanishchev, D.; Jacak, B. V.; Jezghani, M.; Ji, Z.; Jia, J.; Jiang, X.; Johnson, B. M.; Jorjadze, V.; Jouan, D.; Jumper, D. S.; Kanda, S.; Kang, J. H.; Kapukchyan, D.; Karthas, S.; Kawall, D.; Kazantsev, A. V.; Key, J. A.; Khachatryan, V.; Khanzadeev, A.; Kim, C.; Kim, D. J.; Kim, E.-J.; Kim, G. W.; Kim, M.; Kim, M. H.; Kimelman, B.; Kincses, D.; Kistenev, E.; Kitamura, R.; Klatsky, J.; Kleinjan, D.; Kline, P.; Koblesky, T.; Komkov, B.; Kotov, D.; Kudo, S.; Kurgyis, B.; Kurita, K.; Kurosawa, M.; Kwon, Y.; Lacey, R.; Lajoie, J. G.; Lebedev, A.; Lee, S.; Lee, S. H.; Leitch, M. J.; Leung, Y. H.; Lewis, N. A.; Li, X.; Li, X.; Lim, S. H.; Liu, M. X.; Loggins, V.-R.; Lökös, S.; Lovasz, K.; Lynch, D.; Majoros, T.; Makdisi, Y. I.; Makek, M.; Manion, A.; Manko, V. I.; Mannel, E.; Masuda, H.; McCumber, M.; McGaughey, P. L.; McGlinchey, D.; McKinney, C.; Meles, A.; Mendoza, M.; Metzger, W. J.; Mignerey, A. C.; Mihalik, D. E.; Milov, A.; Mishra, D. K.; Mitchell, J. T.; Mitsuka, G.; Miyasaka, S.; Mizuno, S.; Mohanty, A. K.; Montuenga, P.; Moon, T.; Morrison, D. P.; Morrow, S. I.; Moukhanova, T. V.; Murakami, T.; Murata, J.; Mwai, A.; Nagai, K.; Nagashima, K.; Nagashima, T.; Nagle, J. L.; Nagy, M. I.; Nakagawa, I.; Nakagomi, H.; Nakano, K.; Nattrass, C.; Netrakanti, P. K.; Niida, T.; Nishimura, S.; Nouicer, R.; Novák, T.; Novitzky, N.; Nyanin, A. S.; O'Brien, E.; Ogilvie, C. A.; Orjuela Koop, J. D.; Osborn, J. D.; Oskarsson, A.; Ottino, G. J.; Ozawa, K.; Pak, R.; Pantuev, V.; Papavassiliou, V.; Park, J. S.; Park, S.; Pate, S. F.; Patel, M.; Peng, J.-C.; Peng, W.; Perepelitsa, D. V.; Perera, G. D. N.; Peressounko, D. Yu.; Perezlara, C. E.; Perry, J.; Petti, R.; Phipps, M.; Pinkenburg, C.; Pinson, R.; Pisani, R. P.; Pun, A.; Purschke, M. L.; Radzevich, P. V.; Rak, J.; Ramson, B. J.; Ravinovich, I.; Read, K. F.; Reynolds, D.; Riabov, V.; Riabov, Y.; Richford, D.; Rinn, T.; Rolnick, S. D.; Rosati, M.; Rowan, Z.; Rubin, J. G.; Runchey, J.; Safonov, A. S.; Sahlmueller, B.; Saito, N.; Sakaguchi, T.; Sako, H.; Samsonov, V.; Sarsour, M.; Sato, K.; Sato, S.; Schaefer, B.; Schmoll, B. K.; Sedgwick, K.; Seidl, R.; Sen, A.; Seto, R.; Sett, P.; Sexton, A.; Sharma, D.; Shein, I.; Shibata, T.-A.; Shigaki, K.; Shimomura, M.; Shioya, T.; Shukla, P.; Sickles, A.; Silva, C. L.; Silvermyr, D.; Singh, B. K.; Singh, C. P.; Singh, V.; Skoby, M. J.; Slunečka, M.; Snowball, M.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Sourikova, I. V.; Stankus, P. W.; Stepanov, M.; Stoll, S. P.; Sugitate, T.; Sukhanov, A.; Sumita, T.; Sun, J.; Sziklai, J.; Takeda, A.; Taketani, A.; Tanida, K.; Tannenbaum, M. J.; Tarafdar, S.; Taranenko, A.; Tarnai, G.; Tieulent, R.; Timilsina, A.; Todoroki, T.; Tomášek, M.; Towell, C. L.; Towell, R.; Towell, R. S.; Tserruya, I.; Ueda, Y.; Ujvari, B.; van Hecke, H. W.; Vazquez-Carson, S.; Velkovska, J.; Virius, M.; Vrba, V.; Vukman, N.; Wang, X. R.; Wang, Z.; Watanabe, Y.; Watanabe, Y. S.; Wei, F.; White, A. S.; Wong, C. P.; Woody, C. L.; Wysocki, M.; Xia, B.; Xu, C.; Xu, Q.; Xue, L.; Yalcin, S.; Yamaguchi, Y. L.; Yamamoto, H.; Yanovich, A.; Yin, P.; Yoo, J. H.; Yoon, I.; Yu, H.; Yushmanov, I. E.; Zajc, W. A.; Zelenski, A.; Zharko, S.; Zhou, S.; Zou, L.; Phenix Collaboration

    2018-06-01

    We present measurements of the transverse-momentum dependence of elliptic flow v2 for identified pions and (anti)protons at midrapidity (|η |<0.35 ), in 0%-5% central p +Au and 3He+Au collisions at √{sNN}=200 GeV. When taken together with previously published measurements in d +Au collisions at √{sNN}=200 GeV, the results cover a broad range of small-collision-system multiplicities and intrinsic initial geometries. We observe a clear mass-dependent splitting of v2(pT) in d +Au and 3He+Au collisions, just as in large nucleus-nucleus (A +A ) collisions, and a smaller splitting in p +Au collisions. Both hydrodynamic and transport model calculations successfully describe the data at low pT (<1.5 GeV /c ), but fail to describe various features at higher pT. In all systems, the v2 values follow an approximate quark-number scaling as a function of the hadron transverse kinetic energy per constituent quark (K ET/nq ), which was also seen previously in A +A collisions.

  14. Spanish Pre-University Students' Use of English: CEA Results from the University Entrance Examination

    ERIC Educational Resources Information Center

    Diez-Bedmar, Maria Belen

    2011-01-01

    In this paper an updated overview of the main errors that Spanish students make when writing the English exam in the University Entrance Examination is provided. To do so, a Computer-aided Error Analysis (CEA) (Dagneaux, Denness & Granger, 1998) was conducted on a representative sample of the students who took the exam in June 2008 in Jaen,…

  15. Electronic behaviour of Au-Pt alloys and the 4f binding energy shift anomaly in Au bimetallics- X-ray spectroscopy studies

    NASA Astrophysics Data System (ADS)

    Wang, Dongniu; Cui, Xiaoyu; Xiao, Qunfeng; Hu, Yongfeng; Wang, Zhiqiang; Yiu, Y. M.; Sham, T. K.

    2018-06-01

    The electronic structure and charge redistribution of 6s conduction charge and 5d charge in Au and Pt alloys, Au9Pt and AuPt9 have been investigated using a charge compensation model. It is found that, both the Au and Pt 4f binding energy (BE) exhibits a negative shift in the alloys relatively to the pure metal in apparent disagreement with electroneutrality considerations (Au is the most electronegative metallic element); more interestingly, the negative Au 4f BE shift in Au-Pt alloy is in contrast to previous observations for a large number of Au bimetallic systems with more electropositive hosts in which the more electropositive the host„ the more positive the Au 4f BE shift. This anomaly is counter intuitive to electronegativity considerations. This dilemma was resolved by the charge compensation model in which both electronegativity and charge neutrality can be satisfied and the overall charge flow δ, onto Au is small and positive and δ arises from charge flow of 6s conduction charge, Δnc onto Au site, which is partially compensated by the depletion of 6d charge Δnd at the Au site (δ = Δnc+ Δnd ˜0.1 >0). The much larger Coulomb interaction between 4f and 5d than that between 4f and 6s results in positive 4f BE shifts. The Au 4f BE shift in Au-Pt alloys together with 193Au Mössbauer data were used in the charge compensation model analysis which shows that the model is still valid in that the Au 4f shift in Au-Pt alloy arises from mainly conduction charge gain with little depletion of d charge at the Au site. The model also works for Pt. The Au and Pt 5d character in the alloys have been examined with valence band spectra which show both maintain their d characteristic in dilute alloys with Pt d piling up at the Fermi level, and the top of the Au valence band being pushed toward the Fermi level; this is confirmed with DFT densities of state calculations. When Pt is diluted in Au, it gains d charge as evident from the reduction in whiteline intensity

  16. LHC, le Big Bang en éprouvette

    ScienceCinema

    None

    2017-12-09

    Notre compréhension de l’Univers est en train de changer… Bar des Sciences - Tout public Débat modéré par Marie-Odile Montchicourt, journaliste de France Info. Evenement en vidéoconférence entre le Globe de la science et de l’innovation, le bar le Baloard de Montpellier et la Maison des Métallos à Paris. Intervenants au CERN : Philippe Charpentier et Daniel Froideveaux, physiciens au CERN. Intervenants à Paris : Vincent Bontemps, philosophe et chercheur au CEA ; Jacques Arnould, philosophe, historien des sciences et théologien, Jean-Jacques Beineix, réalisateur, producteur, scénariste de cinéma. Intervenants à Montpellier (LPTA) : André Neveu, physicien théoricien et directeur de recherche au CNRS ; Gilbert Moultaka, physicien théoricien et chargé de recherche au CNRS. Partenariat : CERN, CEA, IN2P3, Université MPL2 (LPTA) Dans le cadre de la Fête de la science 2008

  17. Au99(SPh)42 nanomolecules: aromatic thiolate ligand induced conversion of Au144(SCH2CH2Ph)60.

    PubMed

    Nimmala, Praneeth Reddy; Dass, Amala

    2014-12-10

    A new aromatic thiolate protected gold nanomolecule Au99(SPh)42 has been synthesized by reacting the highly stable Au144(SCH2CH2Ph)60 with thiophenol, HSPh. The ubiquitous Au144(SR)60 is known for its high stability even at elevated temperature and in the presence of excess thiol. This report demonstrates for the first time the reactivity of the Au144(SCH2CH2Ph)60 with thiophenol to form a different 99-Au atom species. The resulting Au99(SPh)42 compound, however, is unreactive and highly stable in the presence of excess aromatic thiol. The molecular formula of the title compound is determined by high resolution electrospray mass spectrometry (ESI-MS) and confirmed by the preparation of the 99-atom nanomolecule using two ligands, namely, Au99(SPh)42 and Au99(SPh-OMe)42. This mass spectrometry study is an unprecedented advance in nanoparticle reaction monitoring, in studying the 144-atom to 99-atom size evolution at such high m/z (∼12k) and resolution. The optical and electrochemical properties of Au99(SPh)42 are reported. Other substituents on the phenyl group, HS-Ph-X, where X = -F, -CH3, -OCH3, also show the Au144 to Au99 core size conversion, suggesting minimal electronic effects for these substituents. Control experiments were conducted by reacting Au144(SCH2CH2Ph)60 with HS-(CH2)n-Ph (where n = 1 and 2), bulky ligands like adamantanethiol and cyclohexanethiol. It was observed that conversion of Au144 to Au99 occurs only when the phenyl group is directly attached to the thiol, suggesting that the formation of a 99-atom species is largely influenced by aromaticity of the ligand and less so on the bulkiness of the ligand.

  18. Comparative study of CEA and CA19-9 in esophageal, gastric and colon cancers individually and in combination (ROC curve analysis).

    PubMed

    Bagaria, Bhawna; Sood, Sadhna; Sharma, Rameshwaram; Lalwani, Soniya

    2013-09-01

    To determine the clinical serum levels of carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9), individually and in combination, for the diagnosis of 50 healthy subjects and 150 cases of esophageal, gastric, and colon cancers. The sensitivities of the two markers were compared individually and in combination, with specificity set at 100%. Receiver operating characteristic (ROC) curves were plotted. Serum CEA levels were significantly higher in cancer patients than in the control group. The sensitivity of CEA was determined: in esophageal cancer, sensitivity=28%, negative predictive value (NPV)=61.72%, and AUC=0.742 
(SE=0.05), with a significance level of P<0.0001; in gastric cancer, sensitivity=30%, NPV=58.82%, and AUC=0.734 (SE=0.05), with a significance level of P<0.0001; in colon cancer, sensitivity=74%, NPV=79.36%, and AUC=0.856 
(SE=0.04), with a significance level of P<0.0001. The sensitivity of CA19-9 was also evaluated: in esophageal cancer, sensitivity=18%, NPV=54.94%, and AUC=0.573 (SE =0.05), with a significance level of P=0.2054. In gastric cancer, sensitivity=42%, NPV=63.29%, and AUC=0.679 (SE =0.05), with a significance level of P<0.0011. In colon cancer, sensitivity=26%, NPV=57.47%, and AUC=0.580 (SE =0.05), with a significance level of P=0.1670. The following were the sensitivities of CEA/CA19-9 combined: in esophageal cancer, sensitivity=42%, NPV=63.29%, SE=0.078 (95% CI: 0.0159-0.322); gastric cancer, sensitivity=58%, NPV=70.42%, SE=0.072 (95% CI: -0.0866-0.198); and colon cancer, sensitivity=72%, NPV=78.12%, SE=0.070 (95% CI: 0.137-0.415). CEA exhibited the highest sensitivity for colon cancer, and CA19-9 exhibited the highest sensitivity for gastric cancer. Combined analysis indicated an increase in diagnostic sensitivity in esophageal and gastric cancer compared with that in colon cancer.

  19. Uptake of Au(III) Ions by Aluminum Hydroxide and Their Spontaneous Reduction to Elemental Gold (Au(0)).

    PubMed

    Yokoyama; Matsukado; Uchida; Motomura; Watanabe; Izawa

    2001-01-01

    The behavior of AuCl(4)(-) ions during the formation of aluminum hydroxide at pH 6 was examined. With an increase in NaCl concentration, the content of gold taken up by aluminum hydroxide decreased, suggesting that chloro-hydroxy complexes of Au(III) ion were taken up due to the formation of Al-O-Au bonds. It was found unexpectedly that the Au(III) ions taken up were spontaneously reduced to elemental gold without addition of a specific reducing reagent and then colloidal gold particles were formed. The mechanisms for the uptake of Au(III) ions by aluminum hydroxide and for their spontaneous reduction are discussed. Copyright 2001 Academic Press.

  20. Facile Syntheses of Monodisperse Ultra-Small Au Clusters

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bertino, Massimo F.; Sun, Zhong-Ming; Zhang, Rui

    2006-11-02

    During our effort to synthesize the tetrahedral Au20 cluster, we found a facile synthetic route to prepare monodisperse suspensions of ultra-small Au clusters AuN (N<12) using diphosphine ligands. In our monophasic and single-pot synthesis, a Au precursor ClAu(I)PPh3 and a bidentate phosphine ligand P(Ph)2(CH2)MP(Ph)2 (Ph = phenyl) are dissolved in an organic solvent. Au(I) is reduced slowly by a borane-tert-butylamine complex to form Au clusters coordinated by the diphosphine ligand. The Au clusters are characterized by both high resolution mass spectrometry and UV-Vis absorption spectroscopy. We found that the mean cluster size obtained depends on the chain length M ofmore » the ligand. In particular, a single monodispersed Au11 cluster is obtained with the P(Ph)2(CH2)3P(Ph)2 ligand, whereas P(Ph)2(CH2)MP(Ph)2 ligands with M = 5 and 6 yield Au10 and Au8 clusters. The simplicity of our synthetic method makes it suitable for large-scale production of nearly monodisperse ultrasmall Au clusters. It is suggested that diphosphines provide a set of flexible ligands to allow size-controlled synthesis of Au nanoparticles.« less

  1. STAR Au + Au Fixed Target Results

    NASA Astrophysics Data System (ADS)

    Meehan, Kathryn; STAR Collaboration

    2015-10-01

    The RHIC Beam Energy Scan (BES) program was proposed to look for the turn-off of signatures of the quark gluon plasma (QGP), search for a possible QCD critical point, and study the nature of the phase transition between hadronic and partonic matter. The results from the NA49 experiment at CERN have been used to claim that the onset of deconfinement occurs at a collision energy around a center-of-mass energy of 7 GeV, the low end of the BES range. Data from lower energies are needed to test if this onset occurs. The goal of the STAR Fixed-Target Program is to extend the collision energy range in BES II with the same detector to energies that are likely below the onset of deconfinement. Currently, STAR has inserted a gold target into the beam pipe and conducted test runs at center-of-mass energies 3.9 and 4.5 GeV. Tests have been done with both Au and Al beams. First physics results from a Coulomb analysis of Au + Au fixed-target collisions, which are found to be consistent with previous experiments, will be presented. These results demonstrate that STAR has good particle identification capabilities in this novel detector setup. Furthermore, the Coulomb potential, which is sensitive to the Z of the projectile and degree of baryonic stopping, will be compared with published results from the AGS. This material is based upon work supported by the National Science Foundation under Grant No. 1068833.

  2. Thiol ligand-induced transformation of Au38(SC2H4Ph)24 to Au36(SPh-t-Bu)24.

    PubMed

    Zeng, Chenjie; Liu, Chunyan; Pei, Yong; Jin, Rongchao

    2013-07-23

    We report a disproportionation mechanism identified in the transformation of rod-like biicosahedral Au38(SCH2CH2Ph)24 to tetrahedral Au36(TBBT)24 nanoclusters. Time-dependent mass spectrometry and optical spectroscopy analyses unambiguously map out the detailed size-conversion pathway. The ligand exchange of Au38(SCH2CH2Ph)24 with bulkier 4-tert-butylbenzenethiol (TBBT) until a certain extent starts to trigger structural distortion of the initial biicosahedral Au38(SCH2CH2Ph)24 structure, leading to the release of two Au atoms and eventually the Au36(TBBT)24 nanocluster with a tetrahedral structure, in which process the number of ligands is interestingly preserved. The other product of the disproportionation process, i.e., Au40(TBBT)m+2(SCH2CH2Ph)24-m, was concurrently observed as an intermediate, which was the result of addition of two Au atoms and two TBBT ligands to Au38(TBBT)m(SCH2CH2Ph)24-m. The reaction kinetics on the Au38(SCH2CH2Ph)24 to Au36(TBBT)24 conversion process was also performed, and the activation energies of the structural distortion and disproportionation steps were estimated to be 76 and 94 kJ/mol, respectively. The optical absorption features of Au36(TBBT)24 are interpreted on the basis of density functional theory simulations.

  3. Autonomous Repair Mechanism of Creep Damage in Fe-Au and Fe-Au-B-N Alloys

    NASA Astrophysics Data System (ADS)

    Zhang, S.; Kwakernaak, C.; Tichelaar, F. D.; Sloof, W. G.; Kuzmina, M.; Herbig, M.; Raabe, D.; Brück, E.; van der Zwaag, S.; van Dijk, N. H.

    2015-12-01

    The autonomous repair mechanism of creep cavitation during high-temperature deformation has been investigated in Fe-Au and Fe-Au-B-N alloys. Combined electron-microscopy techniques and atom probe tomography reveal how the improved creep properties result from Au precipitation within the creep cavities, preferentially formed on grain boundaries oriented perpendicular to the applied stress. The selective precipitation of Au atoms at the free creep cavity surface results in pore filling, and thereby, autonomous repair of the creep damage. The large difference in atomic size between the Au and Fe strongly hampers the nucleation of precipitates in the matrix. As a result, the matrix acts as a reservoir for the supersaturated solute until damage occurs. Grain boundaries and dislocations are found to act as fast transport routes for solute gold from the matrix to the creep cavities. The mechanism responsible for the self-healing can be characterized by a simple model for cavity growth and cavity filling.

  4. AuNP-PE interface/phase and its effects on the tensile behaviour of AuNP-PE composites

    NASA Astrophysics Data System (ADS)

    Wang, Yue; Wang, Ruijie; Wang, Chengyuan; Yu, Xiaozhu

    2018-06-01

    A comprehensive study was conducted for a gold nanoparticle (AuNP)-polyethylene (PE) composite. Molecular dynamic (MD) simulations were employed to construct the AuNP-PE systems, achieve their constitutive relations, and measure their tensile properties. Specifically, the AuNP-PE interface/phase was studied via the mass density profile, and its effect was evaluated by comparing the composite with a pure PE matrix. These research studies were followed by the study of the fracture mechanisms and the size and volume fraction effects of AuNPs. Efforts were also made to reveal the underlying physics of the MD simulations. In the present work, an AuNP-PE interface and a densified PE interphase were achieved due to the AuNP-PE van der Waals interaction. Such an interface/phase is found to enhance the Young's modulus and yield stress but decrease the fracture strength and strain.

  5. Flow and bose-einstein correlations in Au-Au collisions at RHIC

    NASA Astrophysics Data System (ADS)

    Phobos Collaboration; Manly, Steven; Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; Garcia, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Henderson, C.; Hofman, D.; Hollis, R. S.; Hołyinski, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2003-03-01

    Argonne flow and Bose-Einstein correlations have been measured in Au-Au collisions at S=130 and 200 GeV using the PHOBOS detector at RHIC. The systematic dependencies of the flow signal on the transverse momentum, pseudorapidity, and centrality of the collision, as well as the beam energy are shown. In addition, results of a 3-dimensional analysis of two-pion correlations in the 200 GeV data are presented.

  6. Application of boronated anti-CEA immunoliposome to tumour cell growth inhibition in in vitro boron neutron capture therapy model.

    PubMed Central

    Yanagië, H.; Tomita, T.; Kobayashi, H.; Fujii, Y.; Takahashi, T.; Hasumi, K.; Nariuchi, H.; Sekiguchi, M.

    1991-01-01

    An immunoliposome containing a 10B-compound has been examined as a selective drug delivery system in boron neutron-capture therapy. Liposomes, conjugated with monoclonal antibodies specific for carcinoembryonic antigen (CEA) were shown to bind selectively to cells bearing CEA on their surface. The immunoliposomes attached to tumour cells suppressed growth in vitro upon thermal neutron irradiation and suppression was dependent upon the concentration of the 10B-compound in the liposomes and on the density of antibody conjugated to the liposomes. The results suggest that immunoliposomes containing the 10B-compound could act as a selective and efficient carrier of 10B atoms to target tumour cells in boron neutron-capture therapy. Images Figure 1 PMID:2021537

  7. Design and Preparation of Supported Au Catalyst with Enhanced Catalytic Activities by Rationally Positioning Au Nanoparticles on Anatase.

    PubMed

    Wang, Liang; Wang, Hong; Rice, Andrew E; Zhang, Wei; Li, Xiaokun; Chen, Mingshu; Meng, Xiangju; Lewis, James P; Xiao, Feng-Shou

    2015-06-18

    A synergistic effect between individual components is crucial for increasing the activity of metal/metal oxide catalysts. The greatest challenge is how to control the synergistic effect to obtain enhanced catalytic performance. Through density functional theory calculations of model Au/TiO2 catalysts, it is suggested that there is strong interaction between Au nanoparticles and Ti species at the edge/corner sites of anatase, which is favorable for the formation of stable oxygen vacancies. Motivated by this theoretical analysis, we have rationally prepared Au nanoparticles attached to edge/corner sites of anatase support (Au/TiO2-EC), confirmed by their HR-TEM images. As expected, this strong interaction is well characterized by Raman, UV-visible, and XPS techniques. Very interestingly, compared with conventional Au catalysts, Au/TiO2-EC exhibits superior catalytic activity in the oxidations using O2. Our approach to controlling Au nanoparticle positioning on anatase to obtain enhanced catalytic activity offers an efficient strategy for developing more novel supported metal catalysts.

  8. Probing Phase Evolutions of Au-Methyl-Propyl-Thiolate Self-Assembled Monolayers on Au(111) at the Molecular Level.

    PubMed

    Gao, Jianzhi; Lin, Haiping; Qin, Xuhui; Zhang, Xin; Ding, Haoxuan; Wang, Yitao; Rokni Fard, Mahroo; Kaya, Dogan; Zhu, Gangqiang; Li, Qing; Li, Youyong; Pan, Minghu; Guo, Quanmin

    2018-06-18

    A self-assembled monolayer (SAM) consisting of a mixture of CH 3 S-Au-SCH 3 , CH 3 S-Au-S(CH 2 ) 2 CH 3 , and CH 3 (CH 2 ) 2 S-Au-S(CH 2 ) 2 CH 3 was studied systematically using scanning tunneling microscopy and density functional calculations. We find that the SAM is subjected to frequent changes at the molecular level on the time scale of ∼minutes. The presence of CH 3 S or CH 3 S-Au as a dissociation product of CH 3 S-Au-SCH 3 plays a key role in the dynamical behavior of the mixed SAM. Slow phase separation takes place at room temperature over hours to days, leading to the formation of methyl-thiolate-rich and propyl-thiolate-rich phases. Our results provide new insights into the chemistry of the thiolate-Au interface, especially for ligand exchange reaction in the RS-Au-SR staple motif.

  9. Photoinduced Glycerol Oxidation over Plasmonic Au and AuM (M = Pt, Pd and Bi) Nanoparticle-Decorated TiO2 Photocatalysts

    PubMed Central

    Jedsukontorn, Trin; Saito, Nagahiro; Hunsom, Mali

    2018-01-01

    In this study, sol-immobilization was used to prepare gold nanoparticle (Au NP)-decorated titanium dioxide (TiO2) photocatalysts at different Au weight % (wt. %) loading (Aux/TiO2, where x is the Au wt. %) and Au–M NP-decorated TiO2 photocatalysts (Au3M3/TiO2), where M is bismuth (Bi), platinum (Pt) or palladium (Pd) at 3 wt. %. The Aux/TiO2 photocatalysts exhibited a stronger visible light absorption than the parent TiO2 due to the localized surface plasmon resonance effect. Increasing the Au content from 1 wt. % to 7 wt. % led to increased visible light absorption due to the increasing presence of defective structures that were capable of enhancing the photocatalytic activity of the as-prepared catalyst. The addition of Pt and Pd coupled with the Au3/TiO2 to form Au3M3/TiO2 improved the photocatalytic activity of the Au3/TiO2 photocatalyst by maximizing their light-absorption property. The Au3/TiO2, Au3Pt3/TiO2 and Au3Pd3/TiO2 photocatalysts promoted the formation of glyceraldehyde from glycerol as the principle product, while Au3Bi3/TiO2 facilitated glycolaldehyde formation as the major product. Among all the prepared photocatalysts, Au3Pd3/TiO2 exhibited the highest photocatalytic activity with a 98.75% glycerol conversion at 24 h of reaction time. PMID:29690645

  10. Sharp Transition from Nonmetallic Au246 to Metallic Au279 with Nascent Surface Plasmon Resonance.

    PubMed

    Higaki, Tatsuya; Zhou, Meng; Lambright, Kelly J; Kirschbaum, Kristin; Sfeir, Matthew Y; Jin, Rongchao

    2018-05-02

    The optical properties of metal nanoparticles have attracted wide interest. Recent progress in controlling nanoparticles with atomic precision (often called nanoclusters) provide new opportunities for investigating many fundamental questions, such as the transition from excitonic to plasmonic state, which is a central question in metal nanoparticle research because it provides insights into the origin of surface plasmon resonance (SPR) as well as the formation of metallic bond. However, this question still remains elusive because of the extreme difficulty in preparing atomically precise nanoparticles larger than 2 nm. Here we report the synthesis and optical properties of an atomically precise Au 279 (SR) 84 nanocluster. Femtosecond transient absorption spectroscopic analysis reveals that the Au 279 nanocluster shows a laser power dependence in its excited state lifetime, indicating metallic state of the particle, in contrast with the nonmetallic electronic structure of the Au 246 (SR) 80 nanocluster. Steady-state absorption spectra reveal that the nascent plasmon band of Au 279 at 506 nm shows no peak shift even down to 60 K, consistent with plasmon behavior. The sharp transition from nonmetallic Au 246 to metallic Au 279 is surprising and will stimulate future theoretical work on the transition and many other relevant issues.

  11. Au crystal growth on natural occurring Au-Ag aggregate elucidated by means of precession electron diffraction (PED)

    NASA Astrophysics Data System (ADS)

    Roqué Rosell, Josep; Portillo Serra, Joaquim; Aiglsperger, Thomas; Plana-Ruiz, Sergi; Trifonov, Trifon; Proenza, Joaquín A.

    2018-02-01

    In the present work, a lamella from an Au-Ag aggregate found in Ni-laterites has been examined using Transmission Electron Microscope to produce a series of Precision Electron Diffraction (PED) patterns. The analysis of the structural data obtained, coupled with Energy Dispersive X-ray microanalysis, made it possible to determine the orientation of twinned native gold growing on the Au-Ag aggregate. The native Au crystal domains are found to have grown at the outermost part of the aggregate whereas the inner core of the aggregate is an Au-Ag alloy (∼4 wt% Ag). The submicron structural study of the natural occurring Au aggregate points to the mobilization and precipitation of gold in laterites and provides insights on Au aggregates development at supergene conditions. This manuscript demonstrates the great potential of electron crystallographic analysis, and in particular, PED to study submicron structural features of micron sized mineral aggregates by using the example of a gold grain found in a Ni-laterite deposits.

  12. Fluorescent probe for turn-on sensing of L-cysteine by ensemble of AuNCs and polymer protected AuNPs.

    PubMed

    Xu, Xiaozhe; Qiao, Juan; Li, Nan; Qi, Li; Zhang, Shufeng

    2015-06-16

    A new fluorescent probe based on ensemble of gold nanoclusters (AuNCs) and polymer protected gold nanoparticles (AuNPs) for turn-on sensing of L-cysteine was designed and prepared. The AuNCs were protected by bovine serum albumin and had strong fluorescence. The polymer protected AuNPs were synthesized by a facile in situ strategy at room temperature and could quench the fluorescence of AuNCs due to the Förster resonance energy transfer. Interestingly, it has been observed that the quenched fluorescence of AuNCs was recovered by L-cysteine, which could induce the aggregation of polymer protected AuNPs by sulfur group. Then the prepared fluorescent probe was successfully used for determination of L-Cys in human urines, which would have an evolving aspect and promote the subsequent exploration. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Au-nanoparticles grafted on plasma treated PE

    NASA Astrophysics Data System (ADS)

    Švorčík, V.; Chaloupka, A.; Řezanka, P.; Slepička, P.; Kolská, Z.; Kasálková, N.; Hubáček, T.; Siegel, J.

    2010-03-01

    Polyethylene (PE) surface was treated with Ar plasma. Activated surface was grafted from methanol solution of 1,2-ethanedithiol. Then the sample was immersed into freshly prepared colloid solution of Au-nanoparticles. Finally Au layer was sputtered on the samples. Properties of the modified PE were studied using various methods: AFM, EPR, RBS and nanoindentation. It was shown that the plasma treatment results in degradation of polymer chain (AFM) and creation of free radicals by EPR. After grafting with dithiol, the concentration of free radicals declines. The presence of Au and S in the surface layer after the coating with Au-nanoparticles was proved by RBS. Plasma treatment changes PE surface morphology and increases surface roughness, too. Another significant change in surface morphology and roughness was observed after deposition of Au-nanoparticles. Nanoindentation measurements show that the grafting with Au-nanoparticles increases adhesion of subsequently sputtered Au layer.

  14. Overview of studies and developments in cinematography, optoelectronic imaging, and photonics at CEA/DIF

    NASA Astrophysics Data System (ADS)

    Mens, Alain; Alozy, Eric; Aubert, Damien; Benier, Jacky; Bourgade, Jean-Luc; Boutin, Jean-Yves; Brunel, Patrick; Charles, Gilbert; Chollet, Clement; Desbat, Laurent; Gontier, Dominique; Jacquet, Henri-Patrick; Jasmin, Serge; Le Breton, Jean-Pierre; Marchet, Bruno; Masclet-Gobin, Isabelle; Mercier, Patrick; Millier, Philippe; Missault, Carole; Negre, Jean-Paul; Paul, Serge; Rosol, Rodolphe; Sommerlinck, Thierry; Veaux, Jacqueline; Veron, Laurent; Vincent de Araujo, Manuel; Jaanimagi, Paul; Pien, Greg

    2003-07-01

    This paper gives an overview of works undertaken at CEA/DIF in high speed cinematography, optoelectronic imaging and ultrafast photonics for the needs of the CEA/DAM experimental programs. We have developed a new multichannel velocimeter, and a new probe for shock breakout timing measurements in detonics experiments. A brief description and a recall of their main performances will be made. We have implemented three new optoelectronic imaging systems, in order to observe dynamic scenes in the ranges of 50 - 100 keV and 4 MeV. These systems are described, their main specifications and performances are given. Then we describe our contribution to the ICF program: after recalling the specifications of LIL plasma diagnostics, we describe the features and performances of visible streak tubes, X-ray streak tubes, visible and X-ray framing cameras and the associated systems developed to match these specifications. At last we introduce the subject of components and systems vulnerability in the LMJ target area, the principles identified to mitigate this problem and the first results of studies (image relay, response of streak tube phosphors, MCP image intensifiers and CCDs to fusion neutrons) related to this subject. Results obtained so far are presented.

  15. Au/ZnO nanoarchitectures with Au as both supporter and antenna of visible-light

    NASA Astrophysics Data System (ADS)

    Liu, Tianyu; Chen, Wei; Hua, Yuxiang; Liu, Xiaoheng

    2017-01-01

    In this paper, we fabricate Au/ZnO nanostructure with smaller ZnO nanoparticles loaded onto bigger gold nanoparticles via combining seed-mediated method and sol-gel method. The obtained Au/ZnO nanocomposites exhibit excellent properties in photocatalysis process like methyl orange (MO) degradation and oxidative conversion of methanol into formaldehyde under visible light irradiation. The enhanced properties were ascribed to the surface plasmon resonance (SPR) effect of Au nanoparticles, which could contribute to the separation of photo-excited electrons and holes and facilitate the process of absorbing visible light. This paper contributes to the emergence of multi-functional nanocomposites with possible applications in visible-light driven photocatalysts and makes the Au/ZnO photocatalyst an exceptional choice for practical applications such as environmental purification of organic pollutants in aqueous solution and the synthesis of fine chemicals and intermediates.

  16. Isomorphism and solid solutions among Ag- and Au-selenides

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Palyanova, Galina A.; Seryotkin, Yurii V.; Novosibirsk State University

    Au-Ag selenides were synthesized by heating stoichiometric mixtures of elementary substances of initial compositions Ag{sub 2−x}Au{sub x}Se with a step of x=0.25 (0≤x≤2) to 1050 °C and annealing at 500 °C. Scanning electron microscopy, optical microscopy, electron microprobe analysis and X-ray powder diffraction methods have been applied to study synthesized samples. Results of studies of synthesized products revealed the existence of three solid solutions with limited isomorphism Ag↔Au: naumannite Ag{sub 2}Se – Ag{sub 1.94}Au{sub 0.06}Se, fischesserite Ag{sub 3}AuSe{sub 2} - Ag{sub 3.2}Au{sub 0.8}Se{sub 2} and gold selenide AuSe - Au{sub 0.94}Ag{sub 0.06}Se. Solid solutions and AgAuSe phases were added tomore » the phase diagram of Ag-Au-Se system. Crystal-chemical interpretation of Ag-Au isomorphism in selenides was made on the basis of structural features of fischesserite, naumannite, and AuSe. - Highlights: • Au-Ag selenides were synthesized. • Limited Ag-Au isomorphism in the selenides is affected by structural features. • Some new phases were introduced to the phase diagram Ag-Au-Se.« less

  17. Energy Dependence of Particle Multiplicities in Central Au+Au Collisions

    NASA Astrophysics Data System (ADS)

    Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Corbo, J.; Decowski, M. P.; Garcia, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Henderson, C.; Hicks, D.; Hofman, D.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A.; Mülmenstädt, J.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Rafelski, M.; Rbeiz, M.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2002-01-01

    We present the first measurement of the pseudorapidity density of primary charged particles in Au+Au collisions at (sNN) = 200 GeV. For the 6% most central collisions, we obtain dNch/dη\\|\\|η\\|<1 = 650+/-35(syst). Compared to collisions at (sNN) = 130 GeV, the highest energy studied previously, an increase by a factor of 1.14+/-0.05 at 90% confidence level, is found. The energy dependence of the pseudorapidity density is discussed in comparison with data from proton-induced collisions and theoretical predictions.

  18. Contribution of the "Institut Scientifique Chérifien" to the development of geoscientific research in Northwest Africa since its creation in 1914

    NASA Astrophysics Data System (ADS)

    Medina, F.

    2013-08-01

    The contribution of the "Institut Scientifique Chérifien", the oldest scientific research centre in Morocco, is reviewed since its creation almost a century ago. Planned in 1914 by the French protectorate of Morocco, this institute has played, since its effective creation in 1920, an important role in the development of several geosciences in North Africa, such as meteorology and climatology, geophysics (gravimetry, magnetism and especially seismology), geomorphology, geology and oceanography. After the independence of Morocco in 1955, several activities, such as meteorology, were transferred elsewhere, but others, such as seismology and magnetism, remained important elements of the centre until recent years. In addition to the research activities, its observatories and libraries that were built during the early years are unique in Northwest Africa.

  19. Electronic and geometric structures of Au30 clusters: a network of 2e-superatom Au cores protected by tridentate protecting motifs with u3-S

    NASA Astrophysics Data System (ADS)

    Tian, Zhimei; Cheng, Longjiu

    2015-12-01

    Density functional theory calculations have been performed to study the experimentally synthesized Au30S(SR)18 and two related Au30(SR)18 and Au30S2(SR)18 clusters. The patterns of thiolate ligands on the gold cores for the three thiolate-protected Au30 nanoclusters are on the basis of the ``divide and protect'' concept. A novel extended protecting motif with u3-S, S(Au2(SR)2)2AuSR, is discovered, which is termed the tridentate protecting motif. The Au cores of Au30S(SR)18, Au30(SR)18 and Au30S2(SR)18 clusters are Au17, Au20 and Au14, respectively. The superatom-network (SAN) model and the superatom complex (SAC) model are used to explain the chemical bonding patterns, which are verified by chemical bonding analysis based on the adaptive natural density partitioning (AdNDP) method and aromatic analysis on the basis of the nucleus-independent chemical shift (NICS) method. The Au17 core of the Au30S(SR)18 cluster can be viewed as a SAN of one Au6 superatom and four Au4 superatoms. The shape of the Au6 core is identical to that revealed in the recently synthesized Au18(SR)14 cluster. The Au20 core of the Au30(SR)18 cluster can be viewed as a SAN of two Au6 superatoms and four Au4 superatoms. The Au14 core of Au30S2(SR)18 can be regarded as a SAN of two pairs of two vertex-sharing Au4 superatoms. Meanwhile, the Au14 core is an 8e-superatom with 1S21P6 configuration. Our work may aid understanding and give new insights into the chemical synthesis of thiolate-protected Au clusters.Density functional theory calculations have been performed to study the experimentally synthesized Au30S(SR)18 and two related Au30(SR)18 and Au30S2(SR)18 clusters. The patterns of thiolate ligands on the gold cores for the three thiolate-protected Au30 nanoclusters are on the basis of the ``divide and protect'' concept. A novel extended protecting motif with u3-S, S(Au2(SR)2)2AuSR, is discovered, which is termed the tridentate protecting motif. The Au cores of Au30S(SR)18, Au30(SR)18 and Au30S

  20. Joint modelling of longitudinal CEA tumour marker progression and survival data on breast cancer

    NASA Astrophysics Data System (ADS)

    Borges, Ana; Sousa, Inês; Castro, Luis

    2017-06-01

    This work proposes the use of Biostatistics methods to study breast cancer in patients of Braga's Hospital Senology Unit, located in Portugal. The primary motivation is to contribute to the understanding of the progression of breast cancer, within the Portuguese population, using a more complex statistical model assumptions than the traditional analysis that take into account a possible existence of a serial correlation structure within a same subject observations. We aim to infer which risk factors aect the survival of Braga's Hospital patients, diagnosed with breast tumour. Whilst analysing risk factors that aect a tumour markers used on the surveillance of disease progression the Carcinoembryonic antigen (CEA). As survival and longitudinal processes may be associated, it is important to model these two processes together. Hence, a joint modelling of these two processes to infer on the association of these was conducted. A data set of 540 patients, along with 50 variables, was collected from medical records of the Hospital. A joint model approach was used to analyse these data. Two dierent joint models were applied to the same data set, with dierent parameterizations which give dierent interpretations to model parameters. These were used by convenience as the ones implemented in R software. Results from the two models were compared. Results from joint models, showed that the longitudinal CEA values were signicantly associated with the survival probability of these patients. A comparison between parameter estimates obtained in this analysis and previous independent survival[4] and longitudinal analysis[5][6], lead us to conclude that independent analysis brings up bias parameter estimates. Hence, an assumption of association between the two processes in a joint model of breast cancer data is necessary. Results indicate that the longitudinal progression of CEA is signicantly associated with the probability of survival of these patients. Hence, an assumption of

  1. Measurements of Strangeness Production on Au+Au collisions at 62 GeV

    NASA Astrophysics Data System (ADS)

    Guimaraes, K. S. F. F.; Munhoz, M. G.; Takahashi, J.; Moura, M. M.; Suaide, A. A. P.; Cosentino, M.

    2005-10-01

    The STAR (Solenoidal Tracker at RHIC) experiment is a large acceptance collider detector that measures primarily hadronic observables to search for signatures of the quark-gluon plasma phase transition and study strongly interacting matter at high energy density. Operational since June 2000, the new heavy ion collider RHIC has already provided Au+Au collisions at σNN = 62, 130 and 200 GeV as well as p+p and d+Au collisions at 200 GeV. The various collision energies and systems allow the systematic study of particle production in heavy ion collisions. In particular, the production of strange (anti-)particles is one of the major topics of STAR. This detector allows the measurement of a variety of particle species at mid-rapidity, like neutral kaons; Λ, Ξ, and Ω. hyperons; and their anti-particles that are reconstructed via their decay topology. The strangeness measurements should provide important information on various phenomenological aspects of ultra-relativistic heavy ion collisions. The goal of this work is to perform the measurement of neutral kaons on Au+Au collisions at 62 GeV. This measurement will bring important information about strangeness production in the energy range between the top RHIC energy and the top SPS energy, where important questions regarding particle production are still open. In this poster, preliminary results of the analysis will be presented, mainly the evaluation of the topological cuts necessary for the neutral kaon reconstruction and the corrections that are necessary to obtain the transverse momentum spectra.

  2. J/ψ suppression at forward rapidity in Au + Au collisions at sNN=39 and 62.4 GeV

    NASA Astrophysics Data System (ADS)

    Adare, A.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Akimoto, R.; Al-Ta'ani, H.; Alexander, J.; Angerami, A.; Aoki, K.; Apadula, N.; Aramaki, Y.; Asano, H.; Aschenauer, E. C.; Atomssa, E. T.; Awes, T. C.; Azmoun, B.; Babintsev, V.; Bai, M.; Bannier, B.; Barish, K. N.; Bassalleck, B.; Bathe, S.; Baublis, V.; Baumgart, S.; Bazilevsky, A.; Belmont, R.; Berdnikov, A.; Berdnikov, Y.; Bing, X.; Blau, D. S.; Boyle, K.; Brooks, M. L.; Buesching, H.; Bumazhnov, V.; Butsyk, S.; Campbell, S.; Castera, P.; Chen, C.-H.; Chi, C. Y.; Chiu, M.; Choi, I. J.; Choi, J. B.; Choi, S.; Choudhury, R. K.; Christiansen, P.; Chujo, T.; Chvala, O.; Cianciolo, V.; Citron, Z.; Cole, B. A.; Connors, M.; Csanád, M.; Csörgő, T.; Dairaku, S.; Datta, A.; Daugherity, M. S.; David, G.; Denisov, A.; Deshpande, A.; Desmond, E. J.; Dharmawardane, K. V.; Dietzsch, O.; Ding, L.; Dion, A.; Donadelli, M.; Drapier, O.; Drees, A.; Drees, K. A.; Durham, J. M.; Durum, A.; D'Orazio, L.; Edwards, S.; Efremenko, Y. V.; Engelmore, T.; Enokizono, A.; Esumi, S.; Eyser, K. O.; Fadem, B.; Fields, D. E.; Finger, M.; Finger, M., Jr.; Fleuret, F.; Fokin, S. L.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fukao, Y.; Fusayasu, T.; Gainey, K.; Gal, C.; Garishvili, A.; Garishvili, I.; Glenn, A.; Gong, X.; Gonin, M.; Goto, Y.; Granier de Cassagnac, R.; Grau, N.; Greene, S. V.; Grosse Perdekamp, M.; Gunji, T.; Guo, L.; Gustafsson, H.-Å.; Hachiya, T.; Haggerty, J. S.; Hahn, K. I.; Hamagaki, H.; Hanks, J.; Hashimoto, K.; Haslum, E.; Hayano, R.; He, X.; Hemmick, T. K.; Hester, T.; Hill, J. C.; Hollis, R. S.; Homma, K.; Hong, B.; Horaguchi, T.; Hori, Y.; Huang, S.; Ichihara, T.; Iinuma, H.; Ikeda, Y.; Imrek, J.; Inaba, M.; Iordanova, A.; Isenhower, D.; Issah, M.; Ivanischev, D.; Jacak, B. V.; Javani, M.; Jia, J.; Jiang, X.; Johnson, B. M.; Joo, K. S.; Jouan, D.; Kamin, J.; Kaneti, S.; Kang, B. H.; Kang, J. H.; Kang, J. S.; Kapustinsky, J.; Karatsu, K.; Kasai, M.; Kawall, D.; Kazantsev, A. V.; Kempel, T.; Khanzadeev, A.; Kijima, K. M.; Kim, B. I.; Kim, C.; Kim, D. J.; Kim, E.-J.; Kim, H. J.; Kim, K.-B.; Kim, Y.-J.; Kim, Y. K.; Kinney, E.; Kiss, Á.; Kistenev, E.; Klatsky, J.; Kleinjan, D.; Kline, P.; Komatsu, Y.; Komkov, B.; Koster, J.; Kotchetkov, D.; Kotov, D.; Král, A.; Krizek, F.; Kunde, G. J.; Kurita, K.; Kurosawa, M.; Kwon, Y.; Kyle, G. S.; Lacey, R.; Lai, Y. S.; Lajoie, J. G.; Lebedev, A.; Lee, B.; Lee, D. M.; Lee, J.; Lee, K. B.; Lee, K. S.; Lee, S. H.; Lee, S. R.; Leitch, M. J.; Leite, M. A. L.; Leitgab, M.; Lewis, B.; Lim, S. H.; Linden Levy, L. A.; Liu, M. X.; Love, B.; Maguire, C. F.; Makdisi, Y. I.; Makek, M.; Manion, A.; Manko, V. I.; Mannel, E.; Masumoto, S.; McCumber, M.; McGaughey, P. L.; McGlinchey, D.; McKinney, C.; Mendoza, M.; Meredith, B.; Miake, Y.; Mibe, T.; Mignerey, A. C.; Milov, A.; Mishra, D. K.; Mitchell, J. T.; Miyachi, Y.; Miyasaka, S.; Mohanty, A. K.; Moon, H. J.; Morrison, D. P.; Motschwiller, S.; Moukhanova, T. V.; Murakami, T.; Murata, J.; Nagae, T.; Nagamiya, S.; Nagle, J. L.; Nagy, M. I.; Nakagawa, I.; Nakamiya, Y.; Nakamura, K. R.; Nakamura, T.; Nakano, K.; Nattrass, C.; Nederlof, A.; Nihashi, M.; Nouicer, R.; Novitzky, N.; Nyanin, A. S.; O'Brien, E.; Ogilvie, C. A.; Okada, K.; Oskarsson, A.; Ouchida, M.; Ozawa, K.; Pak, R.; Pantuev, V.; Papavassiliou, V.; Park, B. H.; Park, I. H.; Park, S. K.; Pate, S. F.; Patel, L.; Pei, H.; Peng, J.-C.; Pereira, H.; Peressounko, D. Yu.; Petti, R.; Pinkenburg, C.; Pisani, R. P.; Proissl, M.; Purschke, M. L.; Qu, H.; Rak, J.; Ravinovich, I.; Read, K. F.; Reynolds, R.; Riabov, V.; Riabov, Y.; Richardson, E.; Roach, D.; Roche, G.; Rolnick, S. D.; Rosati, M.; Sahlmueller, B.; Saito, N.; Sakaguchi, T.; Samsonov, V.; Sano, M.; Sarsour, M.; Sawada, S.; Sedgwick, K.; Seidl, R.; Sen, A.; Seto, R.; Sharma, D.; Shein, I.; Shibata, T.-A.; Shigaki, K.; Shimomura, M.; Shoji, K.; Shukla, P.; Sickles, A.; Silva, C. L.; Silvermyr, D.; Sim, K. S.; Singh, B. K.; Singh, C. P.; Singh, V.; Slunečka, M.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Soumya, M.; Sourikova, I. V.; Stankus, P. W.; Stenlund, E.; Stepanov, M.; Ster, A.; Stoll, S. P.; Sugitate, T.; Sukhanov, A.; Sun, J.; Sziklai, J.; Takagui, E. M.; Takahara, A.; Taketani, A.; Tanaka, Y.; Taneja, S.; Tanida, K.; Tannenbaum, M. J.; Tarafdar, S.; Taranenko, A.; Tennant, E.; Themann, H.; Todoroki, T.; Tomášek, L.; Tomášek, M.; Torii, H.; Towell, R. S.; Tserruya, I.; Tsuchimoto, Y.; Tsuji, T.; Vale, C.; van Hecke, H. W.; Vargyas, M.; Vazquez-Zambrano, E.; Veicht, A.; Velkovska, J.; Vértesi, R.; Virius, M.; Vossen, A.; Vrba, V.; Vznuzdaev, E.; Wang, X. R.; Watanabe, D.; Watanabe, K.; Watanabe, Y.; Watanabe, Y. S.; Wei, F.; Wei, R.; White, S. N.; Winter, D.; Wolin, S.; Woody, C. L.; Wysocki, M.; Yamaguchi, Y. L.; Yang, R.; Yanovich, A.; Ying, J.; Yokkaichi, S.; You, Z.; Younus, I.; Yushmanov, I. E.; Zajc, W. A.; Zelenski, A.

    2012-12-01

    We present measurements of the J/ψ invariant yields in sNN=39 and 62.4 GeV Au + Au collisions at forward rapidity (1.2<|y|<2.2). Invariant yields are presented as a function of both collision centrality and transverse momentum. Nuclear modifications are obtained for central relative to peripheral Au + Au collisions (RCP) and for various centrality selections in Au + Au relative to scaled p + p cross sections obtained from other measurements (RAA). The observed suppression patterns at 39 and 62.4 GeV are quite similar to those previously measured at 200 GeV. This similar suppression presents a challenge to theoretical models that contain various competing mechanisms with different energy dependencies, some of which cause suppression and others enhancement.

  3. Disappearance of back-to-back high-pT hadron correlations in central Au+Au collisions at sqrt[s NN ] =200 GeV.

    PubMed

    Adler, C; Ahammed, Z; Allgower, C; Amonett, J; Anderson, B D; Anderson, M; Averichev, G S; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellwied, R; Berger, J; Bichsel, H; Billmeier, A; Bland, L C; Blyth, C O; Bonner, B E; Boucham, A; Brandin, A; Bravar, A; Cadman, R V; Caines, H; Calderón de la Barca Sánchez, M; Cardenas, A; Carroll, J; Castillo, J; Castro, M; Cebra, D; Chaloupka, P; Chattopadhyay, S; Chen, Y; Chernenko, S P; Cherney, M; Chikanian, A; Choi, B; Christie, W; Coffin, J P; Cormier, T M; Corral, M M; Cramer, J G; Crawford, H J; Derevschikov, A A; Didenko, L; Dietel, T; Draper, J E; Dunin, V B; Dunlop, J C; Eckardt, V; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Fachini, P; Faine, V; Faivre, J; Fatemi, R; Filimonov, K; Finch, E; Fisyak, Y; Flierl, D; Foley, K J; Fu, J; Gagliardi, C A; Gagunashvili, N; Gans, J; Gaudichet, L; Germain, M; Geurts, F; Ghazikhanian, V; Grachov, O; Grigoriev, V; Guedon, M; Gushin, E; Hallman, T J; Hardtke, D; Harris, J W; Henry, T W; Heppelmann, S; Herston, T; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horsley, M; Huang, H Z; Humanic, T J; Igo, G; Ishihara, A; Ivanshin, Yu I; Jacobs, P; Jacobs, W W; Janik, M; Johnson, I; Jones, P G; Judd, E G; Kaneta, M; Kaplan, M; Keane, D; Kiryluk, J; Kisiel, A; Klay, J; Klein, S R; Klyachko, A; Kollegger, T; Konstantinov, A S; Kopytine, M; Kotchenda, L; Kovalenko, A D; Kramer, M; Kravtsov, P; Krueger, K; Kuhn, C; Kulikov, A I; Kunde, G J; Kunz, C L; Kutuev, R Kh; Kuznetsov, A A; Lakehal-Ayat, L; Lamont, M A C; Landgraf, J M; Lange, S; Lansdell, C P; Lasiuk, B; Laue, F; Lauret, J; Lebedev, A; Lednický, R; Leontiev, V M; LeVine, M J; Li, Q; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, L; Liu, Z; Liu, Q J; Ljubicic, T; Llope, W J; LoCurto, G; Long, H; Longacre, R S; Lopez-Noriega, M; Love, W A; Ludlam, T; Lynn, D; Ma, J; Magestro, D; Majka, R; Margetis, S; Markert, C; Martin, L; Marx, J; Matis, H S; Matulenko, Yu A; McShane, T S; Meissner, F; Melnick, Yu; Meschanin, A; Messer, M; Miller, M L; Milosevich, Z; Minaev, N G; Mitchell, J; Moore, C F; Morozov, V; de Moura, M M; Munhoz, M G; Nelson, J M; Nevski, P; Nikitin, V A; Nogach, L V; Norman, B; Nurushev, S B; Odyniec, G; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Paic, G; Pandey, S U; Panebratsev, Y; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Perevoztchikov, V; Peryt, W; Petrov, V A; Planinic, M; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potrebenikova, E; Prindle, D; Pruneau, C; Putschke, J; Rai, G; Rakness, G; Ravel, O; Ray, R L; Razin, S V; Reichhold, D; Reid, J G; Renault, G; Retiere, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Rykov, V; Sakrejda, I; Salur, S; Sandweiss, J; Savin, I; Schambach, J; Scharenberg, R P; Schmitz, N; Schroeder, L S; Schüttauf, A; Schweda, K; Seger, J; Seliverstov, D; Seyboth, P; Shahaliev, E; Shestermanov, K E; Shimanskii, S S; Simon, F; Skoro, G; Smirnov, N; Snellings, R; Sorensen, P; Sowinski, J; Spinka, H M; Srivastava, B; Stephenson, E J; Stock, R; Stolpovsky, A; Strikhanov, M; Stringfellow, B; Struck, C; Suaide, A A P; Sugarbaker, E; Suire, C; Sumbera, M; Surrow, B; Symons, T J M; Szanto de Toledo, A; Szarwas, P; Tai, A; Takahashi, J; Tang, A H; Thein, D; Thomas, J H; Thompson, M; Tikhomirov, V; Tokarev, M; Tonjes, M B; Trainor, T A; Trentalange, S; Tribble, R E; Trofimov, V; Tsai, O; Ullrich, T; Underwood, D G; Van Buren, G; VanderMolen, A M; Vasilevski, I M; Vasiliev, A N; Vigdor, S E; Voloshin, S A; Wang, F; Ward, H; Watson, J W; Wells, R; Westfall, G D; Whitten, C; Wieman, H; Willson, R; Wissink, S W; Witt, R; Wood, J; Xu, N; Xu, Z; Yakutin, A E; Yamamoto, E; Yang, J; Yepes, P; Yurevich, V I; Zanevski, Y V; Zborovský, I; Zhang, H; Zhang, W M; Zoulkarneev, R; Zubarev, A N

    2003-02-28

    Azimuthal correlations for large transverse momentum charged hadrons have been measured over a wide pseudorapidity range and full azimuth in Au+Au and p+p collisions at sqrt[s(NN)]=200 GeV. The small-angle correlations observed in p+p collisions and at all centralities of Au+Au collisions are characteristic of hard-scattering processes previously observed in high-energy collisions. A strong back-to-back correlation exists for p+p and peripheral Au+Au. In contrast, the back-to-back correlations are reduced considerably in the most central Au+Au collisions, indicating substantial interaction as the hard-scattered partons or their fragmentation products traverse the medium.

  4. Observation of D 0 meson nuclear modifications in Au + Au collisions at s NN = 200 GeV

    DOE PAGES

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; ...

    2014-09-30

    We report the first measurement of charmed-hadron (D 0) production via the hadronic decay channel (D 0→K -+π +) in Au+Au collisions at √ sNN=200 GeV with the STAR experiment. The charm production cross section per nucleon-nucleon collision at midrapidity scales with the number of binary collisions, N bin, from p+p to central Au+Au collisions. The D 0 meson yields in central Au+Aucollisions are strongly suppressed compared to those in p+p scaled by N bin, for transverse momenta p T>3 GeV/c, demonstrating significant energy loss of charm quarks in the hot and dense medium. An enhancement at intermediate p Tmore » is also observed. Model calculations including strong charm-medium interactions and coalescence hadronization describe our measurements.« less

  5. Bi-functional Au/FeS (Au/Co3O4) composite for in situ SERS monitoring and degradation of organic pollutants

    NASA Astrophysics Data System (ADS)

    Ma, Shuzhen; Cai, Qian; Lu, Kailing; Liao, Fan; Shao, Mingwang

    2016-01-01

    The bi-functional Au/FeS (Au/Co3O4) composite was fabricated by in situ reducing Au nanoparticles onto the surface of FeS (Co3O4). The as-prepared FeS possessed a multi-structure composed of plenty of nanoplates, which were coated by Au nanoparticles with an average size of 47.5 nm. While the Co3O4 showed a thin hexagonal sheet containing Au nanoparticles on its surface with an average size of 79.0 nm. Both the as-prepared Au/FeS and Au/Co3O4 composites exhibited excellent SERS performance, capable of enhancing the Raman signals of R6G molecules with the enhancement factor up to 1.81 × 106 and 7.60 × 104, respectively. Moreover, Au/FeS (Au/Co3O4) composite also has been verified to have intrinsic peroxidase-like activity, which could decompose H2O2 into hydroxyl radicals and then degrade organic pollutants into small molecules. Therefore, SERS can be used to real-time and in situ monitoring the degradation process of R6G molecules, employing the Au/FeS (Au/Co3O4) composite both as SERS substrate and catalyst.

  6. Gold surfaces and nanoparticles are protected by Au(0)-thiyl species and are destroyed when Au(I)-thiolates form.

    PubMed

    Reimers, Jeffrey R; Ford, Michael J; Halder, Arnab; Ulstrup, Jens; Hush, Noel S

    2016-03-15

    The synthetic chemistry and spectroscopy of sulfur-protected gold surfaces and nanoparticles is analyzed, indicating that the electronic structure of the interface is Au(0)-thiyl, with Au(I)-thiolates identified as high-energy excited surface states. Density-functional theory indicates that it is the noble character of gold and nanoparticle surfaces that destabilizes Au(I)-thiolates. Bonding results from large van der Waals forces, influenced by covalent bonding induced through s-d hybridization and charge polarization effects that perturbatively mix in some Au(I)-thiolate character. A simple method for quantifying these contributions is presented, revealing that a driving force for nanoparticle growth is nobleization, minimizing Au(I)-thiolate involvement. Predictions that Brust-Schiffrin reactions involve thiolate anion intermediates are verified spectroscopically, establishing a key feature needed to understand nanoparticle growth. Mixing of preprepared Au(I) and thiolate reactants always produces Au(I)-thiolate thin films or compounds rather than monolayers. Smooth links to O, Se, Te, C, and N linker chemistry are established.

  7. Identified particle distributions in pp and Au+Au collisions at square root of (sNN)=200 GeV.

    PubMed

    Adams, J; Adler, C; Aggarwal, M M; Ahammed, Z; Amonett, J; Anderson, B D; Anderson, M; Arkhipkin, D; Averichev, G S; Badyal, S K; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellwied, R; Berger, J; Bezverkhny, B I; Bhardwaj, S; Bhaskar, P; Bhati, A K; Bichsel, H; Billmeier, A; Bland, L C; Blyth, C O; Bonner, B E; Botje, M; Boucham, A; Brandin, A; Bravar, A; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca Sánchez, M; Carroll, J; Castillo, J; Castro, M; Cebra, D; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, Y; Chernenko, S P; Cherney, M; Chikanian, A; Choi, B; Christie, W; Coffin, J P; Cormier, T M; Cramer, J G; Crawford, H J; Das, D; Das, S; Derevschikov, A A; Didenko, L; Dietel, T; Dong, X; Draper, J E; Du, F; Dubey, A K; Dunin, V B; Dunlop, J C; Dutta Majumdar, M R; Eckardt, V; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Estienne, M; Fachini, P; Faine, V; Faivre, J; Fatemi, R; Filimonov, K; Filip, P; Finch, E; Fisyak, Y; Flierl, D; Foley, K J; Fu, J; Gagliardi, C A; Ganti, M S; Gutierrez, T D; Gagunashvili, N; Gans, J; Gaudichet, L; Germain, M; Geurts, F; Ghazikhanian, V; Ghosh, P; Gonzalez, J E; Grachov, O; Grigoriev, V; Gronstal, S; Grosnick, D; Guedon, M; Guertin, S M; Gupta, A; Gushin, E; Hallman, T J; Hardtke, D; Harris, J W; Heinz, M; Henry, T W; Heppelmann, S; Herston, T; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horsley, M; Huang, H Z; Huang, S L; Humanic, T J; Igo, G; Ishihara, A; Jacobs, P; Jacobs, W W; Janik, M; Johnson, I; Jones, P G; Judd, E G; Kabana, S; Kaneta, M; Kaplan, M; Keane, D; Kiryluk, J; Kisiel, A; Klay, J; Klein, S R; Klyachko, A; Koetke, D D; Kollegger, T; Konstantinov, A S; Kopytine, M; Kotchenda, L; Kovalenko, A D; Kramer, M; Kravtsov, P; Krueger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kunde, G J; Kunz, C L; Kutuev, R Kh; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; Lansdell, C P; Lasiuk, B; Laue, F; Lauret, J; Lebedev, A; Lednický, R; Leontiev, V M; LeVine, M J; Li, C; Li, Q; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, L; Liu, Z; Liu, Q J; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; Lopez-Noriega, M; Love, W A; Ludlam, T; Lynn, D; Ma, J; Ma, Y G; Magestro, D; Mahajan, S; Mangotra, L K; Mahapatra, D P; Majka, R; Manweiler, R; Margetis, S; Markert, C; Martin, L; Marx, J; Matis, H S; Matulenko, Yu A; McShane, T S; Meissner, F; Melnick, Yu; Meschanin, A; Messer, M; Miller, M L; Milosevich, Z; Minaev, N G; Mironov, C; Mishra, D; Mitchell, J; Mohanty, B; Molnar, L; Moore, C F; Mora-Corral, M J; Morozov, V; de Moura, M M; Munhoz, M G; Nandi, B K; Nayak, S K; Nayak, T K; Nelson, J M; Nevski, P; Nikitin, V A; Nogach, L V; Norman, B; Nurushev, S B; Odyniec, G; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Paic, G; Pandey, S U; Pal, S K; Panebratsev, Y; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Perevoztchikov, V; Peryt, W; Petrov, V A; Phatak, S C; Picha, R; Planinic, M; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M; Potrebenikova, E; Potukuchi, B V K S; Prindle, D; Pruneau, C; Putschke, J; Rai, G; Rakness, G; Raniwala, R; Raniwala, S; Ravel, O; Ray, R L; Razin, S V; Reichhold, D; Reid, J G; Renault, G; Retiere, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Ruan, L J; Sahoo, R; Sakrejda, I; Salur, S; Sandweiss, J; Savin, I; Schambach, J; Scharenberg, R P; Schmitz, N; Schroeder, L S; Schweda, K; Seger, J; Seliverstov, D; Seyboth, P; Shahaliev, E; Shao, M; Sharma, M; Shestermanov, K E; Shimanskii, S S; Singaraju, R N; Simon, F; Skoro, G; Smirnov, N; Snellings, R; Sood, G; Sorensen, P; Sowinski, J; Spinka, H M; Srivastava, B; Stanislaus, S; Stock, R; Stolpovsky, A; Strikhanov, M; Stringfellow, B; Struck, C; Suaide, A A P; Sugarbaker, E; Suire, C; Sumbera, M; Surrow, B; Symons, T J M; de Toledo, A Szanto; Szarwas, P; Tai, A; Takahashi, J; Tang, A H; Thein, D; Thomas, J H; Tikhomirov, V; Tokarev, M; Tonjes, M B; Trainor, T A; Trentalange, S; Tribble, R E; Trivedi, M D; Trofimov, V; Tsai, O; Ullrich, T; Underwood, D G; Van Buren, G; VanderMolen, A M; Vasiliev, A N; Vasiliev, M; Vigdor, S E; Viyogi, Y P; Voloshin, S A; Waggoner, W; Wang, F; Wang, G; Wang, X L; Wang, Z M; Ward, H; Watson, J W; Wells, R; Westfall, G D; Whitten, C; Wieman, H; Willson, R; Wissink, S W; Witt, R; Wood, J; Wu, J; Xu, N; Xu, Z; Xu, Z Z; Yakutin, A E; Yamamoto, E; Yang, J; Yepes, P; Yurevich, V I; Zanevski, Y V; Zborovský, I; Zhang, H; Zhang, H Y; Zhang, W M; Zhang, Z P; Zołnierczuk, P A; Zoulkarneev, R; Zoulkarneeva, J; Zubarev, A N

    2004-03-19

    Transverse mass and rapidity distributions for charged pions, charged kaons, protons, and antiprotons are reported for square root of [sNN]=200 GeV pp and Au+Au collisions at Relativistic Heary Ion Collider (RHIC). Chemical and kinetic equilibrium model fits to our data reveal strong radial flow and long duration from chemical to kinetic freeze-out in central Au+Au collisions. The chemical freeze-out temperature appears to be independent of initial conditions at RHIC energies.

  8. Big Data solution for CTBT monitoring: CEA-IDC joint global cross correlation project

    NASA Astrophysics Data System (ADS)

    Bobrov, Dmitry; Bell, Randy; Brachet, Nicolas; Gaillard, Pierre; Kitov, Ivan; Rozhkov, Mikhail

    2014-05-01

    Waveform cross-correlation when applied to historical datasets of seismic records provides dramatic improvements in detection, location, and magnitude estimation of natural and manmade seismic events. With correlation techniques, the amplitude threshold of signal detection can be reduced globally by a factor of 2 to 3 relative to currently standard beamforming and STA/LTA detector. The gain in sensitivity corresponds to a body wave magnitude reduction by 0.3 to 0.4 units and doubles the number of events meeting high quality requirements (e.g. detected by three and more seismic stations of the International Monitoring System (IMS). This gain is crucial for seismic monitoring under the Comprehensive Nuclear-Test-Ban Treaty. The International Data Centre (IDC) dataset includes more than 450,000 seismic events, tens of millions of raw detections and continuous seismic data from the primary IMS stations since 2000. This high-quality dataset is a natural candidate for an extensive cross correlation study and the basis of further enhancements in monitoring capabilities. Without this historical dataset recorded by the permanent IMS Seismic Network any improvements would not be feasible. However, due to the mismatch between the volume of data and the performance of the standard Information Technology infrastructure, it becomes impossible to process all the data within tolerable elapsed time. To tackle this problem known as "BigData", the CEA/DASE is part of the French project "DataScale". One objective is to reanalyze 10 years of waveform data from the IMS network with the cross-correlation technique thanks to a dedicated High Performance Computer (HPC) infrastructure operated by the Centre de Calcul Recherche et Technologie (CCRT) at the CEA of Bruyères-le-Châtel. Within 2 years we are planning to enhance detection and phase association algorithms (also using machine learning and automatic classification) and process about 30 terabytes of data provided by the IDC to

  9. CEA, CA 15-3, and TPS as Prognostic Factors in the Follow-up Monitoring of Patients After Radical Surgery for Breast Cancer.

    PubMed

    Svobodova, Sarka; Kucera, Radek; Fiala, Ondrej; Marie, Karlikova; Narsanska, Andrea; Zedníková, Ilona; Treska, Vladislav; Slouka, David; Milena, Rousarova; Topolcan, Ondrej; Finek, Jindrich

    2018-01-01

    The aim of this study was to evaluate the ability of tissue polypeptide-specific antigen (TPS), carcinoembryonic antigen (CEA), and cancer antigen 15-3 (CA 15-3) to predict relapse in breast cancer patients, when the measurement of biomarkers is performed within 6 months after surgery. Four hundred and seventy-two patients with breast cancer were evaluated. TPS, CEA, and CA 15-3 were measured in months 1, 3, and 6, after surgery. Disease recurrence was recorded between 7-12 months after surgery. Disease recurrence occurred in 60 patients, while 412 patients remained in recurrence-free status. TPS levels of the recurrence group differed statistically significantly in the first and sixth month after surgery compared to recurrence-free group (p=0.0339, AUC=0.6056; p<0.0001, AUC=0.7196). CEA and CA 15-3 measurements did not achieve a statistically significant difference for any month examined. TPS level in the sixth month after surgery is the best candidate biomarker to predict disease recurrence. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  10. Surface plasmon aided high sensitive non-enzymatic glucose sensor using Au/NiAu multilayered nanowire arrays.

    PubMed

    Wang, Lanfang; Zhu, Weiqi; Lu, Wenbo; Qin, Xiufang; Xu, Xiaohong

    2018-07-15

    A novel plasmon aided non-enzymatic glucose sensor was first constructed based on the unique half-rough Au/NiAu multilayered nanowire arrays. These multilayered and half-rough nanowires provide high chemical activity and large surface area for glucose oxidation in an alkaline solution. Under visible light irradiation, the surface plasmons originated from Au part enhance the electron transfer in the vertically aligned nanowires, leading to high sensitivity and wide detection range. The resulting sensor exhibits a wide glucose detection concentration range, low detection limit, and high sensitivity for plasmon aided non-enzymatic glucose sensor. Moreover, the detection sensitivity is enhanced by almost 2 folds compared to that in the dark, which significantly enhanced the performance of Au/NiAu multilayered nanowire arrays sensor. An excellent selectivity and acceptable stability were also achieved. These results indicate that surface plasmon aided nanostructures are promising new platforms for the construction of non-enzymatic glucose sensors. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Collective flow measurements with HADES in Au+Au collisions at 1.23A GeV

    NASA Astrophysics Data System (ADS)

    Kardan, Behruz; Hades Collaboration

    2017-11-01

    HADES has a large acceptance combined with a good mass-resolution and therefore allows the study of dielectron and hadron production in heavy-ion collisions with unprecedented precision. With the statistics of seven billion Au-Au collisions at 1.23A GeV recorded in 2012, the investigation of higher-order flow harmonics is possible. At the BEVALAC and SIS18 directed and elliptic flow has been measured for pions, charged kaons, protons, neutrons and fragments, but higher-order harmonics have not yet been studied. They provide additional important information on the properties of the dense hadronic medium produced in heavy-ion collisions. We present here a high-statistics, multidifferential measurement of v1 and v2 for protons in Au+Au collisions at 1.23A GeV.

  12. Coincidence studies of He ionized by C{sup 6+}, Au{sup 24+}, and Au{sup 53+}

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    McGovern, M.; Walters, H. R. J.; Assafrao, D.

    2010-04-15

    A recently developed [Phys. Rev. A 79, 042707 (2009)] impact parameter coupled pseudostate approximation (CP) is applied to calculate triple differential cross sections for single ionization of He by C{sup 6+}, Au{sup 24+}, and Au{sup 53+} projectiles at impact energies of 100 and 2 MeV/amu for C{sup 6+} and 3.6 MeV/amu for Au{sup 24+} and Au{sup 53+}. For C{sup 6+}, satisfactory, but not perfect, agreement is found with experimental measurements in coplanar geometry, but there is substantial disagreement with data taken in a perpendicular plane geometry. The CP calculations firmly contradict a projectile-nucleus interaction model which has been used tomore » support the perpendicular plane measurements. For Au{sup 24+} and Au{sup 53+}, there is a complete lack of accord with the available experiments. However, for Au{sup 24+} the theoretical position appears to be quite firm with clear indications of convergence in the CP approximation and very good agreement between CP and the completely different three-distorted-waves eikonal-initial-state (3DW-EIS) approximation. The situation for Au{sup 53+} is different. At the momentum transfers at which the measurements were made, there are doubts about the convergence of the CP approximation and a factor of 2 difference between the CP and 3DW-EIS predictions. The discord between theory and experiment is even greater with the experiment giving cross sections a factor of 10 larger than the theory. A study of the convergence of the CP approximation shows that it improves rapidly with reducing momentum transfer. As a consequence, lower-order cross sections than the triple are quite well converged and present an opportunity for a more reliable test of the experiment.« less

  13. Isomorphism and solid solutions among Ag- and Au-selenides

    NASA Astrophysics Data System (ADS)

    Palyanova, Galina A.; Seryotkin, Yurii V.; Kokh, Konstantin A.; Bakakin, Vladimir V.

    2016-09-01

    Au-Ag selenides were synthesized by heating stoichiometric mixtures of elementary substances of initial compositions Ag2-xAuxSe with a step of х=0.25 (0≤х≤2) to 1050 °С and annealing at 500 °C. Scanning electron microscopy, optical microscopy, electron microprobe analysis and X-ray powder diffraction methods have been applied to study synthesized samples. Results of studies of synthesized products revealed the existence of three solid solutions with limited isomorphism Ag↔Au: naumannite Ag2Se - Ag1.94Au0.06Se, fischesserite Ag3AuSe2 - Ag3.2Au0.8Se2 and gold selenide AuSe - Au0.94Ag0.06Se. Solid solutions and AgAuSe phases were added to the phase diagram of Ag-Au-Se system. Crystal-chemical interpretation of Ag-Au isomorphism in selenides was made on the basis of structural features of fischesserite, naumannite, and AuSe.

  14. Strange baryon resonance production in sqrt s NN=200 GeV p+p and Au+Au collisions.

    PubMed

    Abelev, B I; Aggarwal, M M; Ahammed, Z; Amonett, J; Anderson, B D; Anderson, M; Arkhipkin, D; Averichev, G S; Bai, Y; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellingeri-Laurikainen, A; Bellwied, R; Benedosso, F; Bhardwaj, S; Bhasin, A; Bhati, A K; Bichsel, H; Bielcik, J; Bielcikova, J; Bland, L C; Blyth, S-L; Bonner, B E; Botje, M; Bouchet, J; Brandin, A V; Bravar, A; Burton, T P; Bystersky, M; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca Sánchez, M; Castillo, J; Catu, O; Cebra, D; Chajecki, Z; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, J H; Cheng, J; Cherney, M; Chikanian, A; Christie, W; Coffin, J P; Cormier, T M; Cosentino, M R; Cramer, J G; Crawford, H J; Das, D; Das, S; Dash, S; Daugherity, M; de Moura, M M; Dedovich, T G; DePhillips, M; Derevschikov, A A; Didenko, L; Dietel, T; Djawotho, P; Dogra, S M; Dong, W J; Dong, X; Draper, J E; Du, F; Dunin, V B; Dunlop, J C; Dutta Mazumdar, M R; Eckardt, V; Edwards, W R; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Estienne, M; Fachini, P; Fatemi, R; Fedorisin, J; Filimonov, K; Filip, P; Finch, E; Fine, V; Fisyak, Y; Fu, J; Gagliardi, C A; Gaillard, L; Ganti, M S; Gaudichet, L; Ghazikhanian, V; Ghosh, P; Gonzalez, J E; Gorbunov, Y G; Gos, H; Grebenyuk, O; Grosnick, D; Guertin, S M; Guimaraes, K S F F; Gupta, N; Gutierrez, T D; Haag, B; Hallman, T J; Hamed, A; Harris, J W; He, W; Heinz, M; Henry, T W; Hepplemann, S; Hippolyte, B; Hirsch, A; Hjort, E; Hoffman, A M; Hoffmann, G W; Horner, M J; Huang, H Z; Huang, S L; Hughes, E W; Humanic, T J; Igo, G; Jacobs, P; Jacobs, W W; Jakl, P; Jia, F; Jiang, H; Jones, P G; Judd, E G; Kabana, S; Kang, K; Kapitan, J; Kaplan, M; Keane, D; Kechechyan, A; Khodyrev, V Yu; Kim, B C; Kiryluk, J; Kisiel, A; Kislov, E M; Klein, S R; Kocoloski, A; Koetke, D D; Kollegger, T; Kopytine, M; Kotchenda, L; Kouchpil, V; Kowalik, K L; Kramer, M; Kravtsov, P; Kravtsov, V I; Krueger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; LaPointe, S; Laue, F; Lauret, J; Lebedev, A; Lednicky, R; Lee, C-H; Lehocka, S; LeVine, M J; Li, C; Li, Q; Li, Y; Lin, G; Lin, X; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, H; Liu, J; Liu, L; Liu, Z; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; Love, W A; Lu, Y; Ludlam, T; Lynn, D; Ma, G L; Ma, J G; Ma, Y G; Magestro, D; Mahapatra, D P; Majka, R; Mangotra, L K; Manweiler, R; Margetis, S; Markert, C; Martin, L; Matis, H S; Matulenko, Yu A; McClain, C J; McShane, T S; Melnick, Yu; Meschanin, A; Millane, J; Miller, M L; Minaev, N G; Mioduszewski, S; Mironov, C; Mischke, A; Mishra, D K; Mitchell, J; Mohanty, B; Molnar, L; Moore, C F; Morozov, D A; Munhoz, M G; Nandi, B K; Nattrass, C; Nayak, T K; Nelson, J M; Netrakanti, P K; Nogach, L V; Nurushev, S B; Odyniec, G; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Pachr, M; Pal, S K; Panebratsev, Y; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Peitzmann, T; Perevoztchikov, V; Perkins, C; Peryt, W; Phatak, S C; Picha, R; Planinic, M; Pluta, J; Poljak, N; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M; Potrebenikova, E; Potukuchi, B V K S; Prindle, D; Pruneau, C; Putschke, J; Rakness, G; Raniwala, R; Raniwala, S; Ray, R L; Razin, S V; Reinnarth, J; Relyea, D; Retiere, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Rose, A; Roy, C; Ruan, L; Russcher, M J; Sahoo, R; Sakuma, T; Salur, S; Sandweiss, J; Sarsour, M; Sazhin, P S; Schambach, J; Scharenberg, R P; Schmitz, N; Schweda, K; Seger, J; Selyuzhenkov, I; Seyboth, P; Shabetai, A; Shahaliev, E; Shao, M; Sharma, M; Shen, W Q; Shimanskiy, S S; Sichtermann, E; Simon, F; Singaraju, R N; Smirnov, N; Snellings, R; Sood, G; Sorensen, P; Sowinski, J; Speltz, J; Spinka, H M; Srivastava, B; Stadnik, A; Stanislaus, T D S; Stock, R; Stolpovsky, A; Strikhanov, M; Stringfellow, B; Suaide, A A P; Sugarbaker, E; Sumbera, M; Sun, Z; Surrow, B; Swanger, M; Symons, T J M; Szanto de Toledo, A; Tai, A; Takahashi, J; Tang, A H; Tarnowsky, T; Thein, D; Thomas, J H; Timmins, A R; Timoshenko, S; Tokarev, M; Trainor, T A; Trentalange, S; Tribble, R E; Tsai, O D; Ulery, J; Ullrich, T; Underwood, D G; Buren, G Van; van der Kolk, N; van Leeuwen, M; Molen, A M Vander; Varma, R; Vasilevski, I M; Vasiliev, A N; Vernet, R; Vigdor, S E; Viyogi, Y P; Vokal, S; Voloshin, S A; Waggoner, W T; Wang, F; Wang, G; Wang, J S; Wang, X L; Wang, Y; Watson, J W; Webb, J C; Westfall, G D; Wetzler, A; Whitten, C; Wieman, H; Wissink, S W; Witt, R; Wood, J; Wu, J; Xu, N; Xu, Q H; Xu, Z; Yepes, P; Yoo, I-K; Yurevich, V I; Zhan, W; Zhang, H; Zhang, W M; Zhang, Y; Zhang, Z P; Zhao, Y; Zhong, C; Zoulkarneev, R; Zoulkarneeva, Y; Zubarev, A N; Zuo, J X

    2006-09-29

    We report the measurements of Sigma(1385) and Lambda(1520) production in p+p and Au+Au collisions at sqrt[s{NN}]=200 GeV from the STAR Collaboration. The yields and the p(T) spectra are presented and discussed in terms of chemical and thermal freeze-out conditions and compared to model predictions. Thermal and microscopic models do not adequately describe the yields of all the resonances produced in central Au+Au collisions. Our results indicate that there may be a time span between chemical and thermal freeze-out during which elastic hadronic interactions occur.

  15. Une alternative au cobalt pour la synthese de nanotubes de carbone monoparoi par plasma inductif thermique

    NASA Astrophysics Data System (ADS)

    Carrier, Jean-Francois

    Les nanotubes de carbone de type monoparoi (C-SWNT) sont une classe recente de nanomateriaux qui ont fait leur apparition en 1991. L'interet qu'on leur accorde provient des nombreuses proprietes d'avant-plan qu'ils possedent. Leur resistance mecanique serait des plus rigide, tout comme ils peuvent conduire l'electricite et la chaleur d'une maniere inegalee. Non moins, les C-SWNT promettent de devenir une nouvelle classe de plateforme moleculaire, en servant de site d'attache pour des groupements reactifs. Les promesses de ce type particulier de nanomateriau sont nombreuses, la question aujourd'hui est de comment les realiser. La technologie de synthese par plasma inductif thermique se situe avantageusement pour la qualite de ses produits, sa productivite et les faibles couts d'operation. Par contre, des recherches recentes ont permis de mettre en lumiere des risques d'expositions reliees a l'utilisation du cobalt, comme catalyseur de synthese; son elimination ou bien son remplacement est devenu une preoccupation importante. Quatre recettes alternatives ont ete mises a l'essai afin de trouver une alternative plus securitaire a la recette de base; un melange catalytique ternaire, compose de nickel, de cobalt et d'oxyde d'yttrium. La premiere consiste essentiellement a remplacer la proportion massique de cobalt par du nickel, qui etait deja present dans la recette de base. Les trois options suivantes contiennent de nouveaux catalyseurs, en remplacement au Co, qui sont apparus dans plusieurs recherches scientifiques au courant des dernieres annees: le dioxyde de zircone (ZrO2), dioxyde de manganese (MnO2) et le molybdene (Mo). La methode utilisee consiste a vaporiser la matiere premiere, sous forme solide, dans un reacteur plasma a haute frequence (3 MHz) a paroi refroidi. Apres le passage dans le plasma, le systeme traverse une section dite de "croissance", isolee thermiquement a l'aide de graphite, afin de maintenir une certaine plage de temperature favorable a la

  16. Growth of germanium on Au(111): formation of germanene or intermixing of Au and Ge atoms?

    PubMed

    Cantero, Esteban D; Solis, Lara M; Tong, Yongfeng; Fuhr, Javier D; Martiarena, María Luz; Grizzi, Oscar; Sánchez, Esteban A

    2017-07-19

    We studied the growth of Ge layers on Au(111) under ultra-high vacuum conditions from the submonolayer regime up to a few layers with Scanning Tunneling Microscopy (STM), Direct Recoiling Spectroscopy (DRS) and Low Energy Electron Diffraction (LEED). Most STM images for the thicker layers are consistent with a commensurate 5 × 8 arrangement. The high surface sensitivity of TOF-DRS allows us to confirm the coexistence of Au and Ge atoms in the top layer for all stages of growth. An estimation of the Au to Ge ratio at the surface of the thick layer gives about 1 Au atom per 2 Ge ones. When the growth is carried out at sample temperatures higher than about 420 K, a fraction of the deposited Ge atoms migrate into the bulk of Au. This incorporation of Ge into the bulk reduces the growth rate of the Ge films, making it more difficult to obtain films thicker than a few layers. After sputtering the Ge/Au surface, the segregation of bulk Ge atoms to the surface occurs for temperatures ≥600 K. The surface obtained after segregation of Ge reaches a stable condition (saturation) with an n × n symmetry with n on the order of 14.

  17. Electron flow in large metallomacromolecules and electronic switch of nanoparticle stabilization: new click ferrocenyl dentromers that reduce Au(III) to Au nanoparticles.

    PubMed

    Astruc, Didier; Wang, Qi; Fu, Fangyu; Martinez-Villacorta, Angel M; Moya, Sergio; Salmon, Lionel; Ruiz, Jaime; Hunel, Julien; Vax, Amélie

    2018-06-04

    Click ferrocenyl-terminal dentromers, a family of arene-cored dendrimers with triple branching (9-Fc, 27-Fc, 81-Fc and 243-Fc) reduce Au(III) to ferricinium dentromer-stabilized Au nanoparticles (AuNPs). Cyclic voltammetry studies in CH2Cl2 show reversible CV waves with some adsorption for the 243-Fc dentromer and a number of redox groups found, 255 ± 25, using the Bard-Anson method, close to the theoretical number of 243. The dentromers reduce aqueous HAuCl4 to water-soluble ferricinium chloride dentromer-stabilized gold nanoparticles (AuNPs) with core sizes between 30 and 47 nm. These triazolylferricinium dentromer-stabilized AuNPs are reduced by cobaltocene to cobalticinium chloride and ferrocene dentromer-weakly stabilized AuNPs together with red shift of the AuNP plasmon. The weakness of the AuNP stabilization is characterized by dentromer extraction with CH2Cl2 along with irreversible AuNP agglomeration for the 9, 27 and 81-ferrocenyl dentromer, only the 243-ferrocenyl dentromer-AuNP withstanding this process. Altogether this demonstrates the electronic switch of the dentromer-mediated AuNP stabilization. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Highly Stable [C60AuC60]+/- Dumbbells.

    PubMed

    Goulart, Marcelo; Kuhn, Martin; Martini, Paul; Chen, Lei; Hagelberg, Frank; Kaiser, Alexander; Scheier, Paul; Ellis, Andrew M

    2018-05-17

    Ionic complexes between gold and C 60 have been observed for the first time. Cations and anions of the type [Au(C 60 ) 2 ] +/- are shown to have particular stability. Calculations suggest that these ions adopt a C 60 -Au-C 60 sandwich-like (dumbbell) structure, which is reminiscent of [XAuX] +/- ions previously observed for much smaller ligands. The [Au(C 60 ) 2 ] +/- ions can be regarded as Au(I) complexes, regardless of whether the net charge is positive or negative, but in both cases, the charge transfer between the Au and C 60 is incomplete, most likely because of a covalent contribution to the Au-C 60 binding. The C 60 -Au-C 60 dumbbell structure represents a new architecture in fullerene chemistry that might be replicable in synthetic nanostructures.

  19. Heterojunction metal-oxide-metal Au-Fe{sub 3}O{sub 4}-Au single nanowire device for spintronics

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Reddy, K. M., E-mail: mrkongara@boisestate.edu; Punnoose, Alex; Hanna, Charles

    2015-05-07

    In this report, we present the synthesis of heterojunction magnetite nanowires in alumina template and describe magnetic and electrical properties from a single nanowire device for spintronics applications. Heterojunction Au-Fe-Au nanowire arrays were electrodeposited in porous aluminum oxide templates, and an extensive and controlled heat treatment process converted Fe segment to nanocrystalline cubic magnetite phase with well-defined Au-Fe{sub 3}O{sub 4} interfaces as confirmed by the transmission electron microscopy. Magnetic measurements revealed Verwey transition shoulder around 120 K and a room temperature coercive field of 90 Oe. Current–voltage (I-V) characteristics of a single Au-Fe{sub 3}O{sub 4}-Au nanowire have exhibited Ohmic behavior. Anomalous positivemore » magnetoresistance of about 0.5% is observed on a single nanowire, which is attributed to the high spin polarization in nanowire device with pure Fe{sub 3}O{sub 4} phase and nanocontact barrier. This work demonstrates the ability to preserve the pristine Fe{sub 3}O{sub 4} and well defined electrode contact metal (Au)–magnetite interface, which helps in attaining high spin polarized current.« less

  20. Disentangling flow and signals of Chiral Magnetic Effect in U+U, Au+Au and p+Au collisions

    NASA Astrophysics Data System (ADS)

    Tribedy, Prithwish; STAR Collaboration

    2017-11-01

    We present STAR measurements of the charge-dependent three-particle correlator γ a , b = 〈 cos ⁡ (ϕ1a + ϕ2b - 2ϕ3) 〉 /v2 { 2 } and elliptic flow v2 { 2 } in U+U, Au+Au and p+Au collisions at RHIC. The difference Δγ = γ (opposite-sign) - γ (same-sign) measures charge separation across the reaction plane, a predicted signal of the Chiral Magnetic Effect (CME). Although charge separation has been observed, it has been argued that the measured separation can also be explained by elliptic flow related backgrounds. In order to separate the two effects we perform measurements of the γ-correlator where background expectations differ from magnetic field driven effects. A differential measurement of γ with the relative pseudorapidity (Δη) between the first and second particles indicate that Δγ in peripheral A+A and p+A collisions are dominated by short-range correlations in Δη. However, a relatively wider component of the correlation in Δη tends to vanish the same way as projected magnetic field as predicted by MC-Glauber simulations.

  1. Neuropeptide Y (NPY) in the central nucleus of the amygdala (CeA) does not affect ethanol-reinforced responding in binge-drinking, nondependent rats.

    PubMed

    Henderson, Angela N; Czachowski, Cristine L

    2012-03-01

    The central nucleus of the amygdala (CeA) has been implicated as having a significant role in mediating alcohol-drinking behavior. Neuropeptide Y (NPY) has been investigated as a potential pharmacotherapeutic due to its ability to attenuate ethanol intake, particularly when administered into the CeA. Previous research suggests, though the evidence is somewhat conflicting, that the efficacy of NPY is contingent upon genetic background and/or prior history of ethanol dependence in rats. However, studies looking at the effects of NPY in nonselected animals lacking a history of ethanol dependence have two factors that could impact the interpretation of the results: ethanol history/selection AND relatively low baseline ethanol intakes as compared to ethanol-dependent and/or genetically selected controls. The purpose of the present study was to generate higher baseline ethanol intakes upon which to examine the effects of NPY on ethanol and sucrose drinking in nonselected rats using a binge drinking model. Long Evans rats were trained to complete a single response requirement resulting in access to either 2% sucrose (Sucrose Group) or 2% sucrose/10% ethanol (Ethanol Group) for a 20-min drinking session. On treatment days, rats were bilaterally microinjected into the CeA with aCSF or one of three doses of NPY (0.25μg, 0.50μg, or 1.00μg/.5μL). Subjects in the Ethanol Group were consuming an average of 1.2g/kg of ethanol (yielding BELs of ~90mg%) during the 20min access period following aCSF treatments. The results revealed that NPY had no effect on either sucrose or ethanol consumption or on appetitive responding (latency to respond). Overall, the findings indicate that even a history of binge-like ethanol consumption is not sufficient to recruit CeA NPY activity, and are consistent with previous studies showing that the role of NPY in regulating ethanol reinforcement in the CeA may be contingent upon a prior history of ethanol dependence. Copyright © 2011 Elsevier Inc

  2. Initial Eccentricity in Deformed 197Au+197Au and 238U+238U Collisions at RHIC

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Filip, Peter; Lednicky, Richard; Masui, Hiroshi

    2010-07-07

    Initial eccentricity and eccentricity fluctuations of the interaction volume created in relativistic collisions of deformed {sup 197}Au and {sup 238}U nuclei are studied using optical and Monte-Carlo (MC) Glauber simulations. It is found that the non-sphericity noticeably influences the average eccentricity in central collisions and eccentricity fluctuations are enhanced due to deformation. Quantitative results are obtained for Au+Au and U+U collisions at energy {radical}s{sub NN} = 200 GeV.

  3. [Relation between the level of TPS, NSE, CEA and beta2-mG in the serum and the biological behavior of small cell lung cancer].

    PubMed

    Chen, Ming-sheng; Xu, Yan; Ma, Jing; Wu, Chang-gui; Hao, Xiao-ke; Lu, Bao-bi; Liu, Tian

    2007-08-01

    To study the relation between the level of tissue polypeptide specific antigen (TPS), neuron-specific enolase (NSE), carcinoembryonic antigen (CEA) and beta(2)-microglobulin (beta(2)-mG) in serum and the biological behavior of lung cancer for the more scientific diagnosis of lung cancer. To detect the level of TPS, NSE, CEA and beta(2)-mG in the serum of 94 patients with small cell lung cancer (SCLC), 86 patients with benign pulmonary diseases (BPD) and 89 patients in normal control group, the level of serum were examined by ELISA and immunoradiometric assay. The level of TPS and NSE in the serum of SCLC group [(437.8+/-516.6) U/L, (76.8+/-91.4) microg/L] were much higher than those in BPD group [(143.6+/-78.7) U/L, (13.3+/-10.8) microg/L] and normal group [(98.4+/-58.9) U/L, (10.1+/-5.7) microg/L, P<0.01)], and the level of CEA and beta(2)-mG in the serum of SCLC group were also obviously higher than those in normal group and BPD group (P<0.01). The sensitivity, specificity and accuracy of SCLC'S diagnosis by an indicator of TPS and NSE were 84.4%, 87.8%, 83.6% and 79.3%, 93.7%, 88.3%, respectively, and were much higher than CEA and beta(2)-Mg. In addition, the level of TPS and NSE in the patients' serum with metastatic SCLC were markedly higher than those in the patients with SCLC without metastasis, increased with the number of metastatic focuses. In clinical practice, the possibility of smokers suffering from lung cancer disease is 8 to 10 times higher than that of no-smokers, and 10 to 24 times higher of the people who smoked 30 to 40 cigarettes per day. From this comparison, the amount of smoking was closely related to the occurrence of lung cancer. TPS, NSE, CEA and beta(2)-mG in serum are useful for early diagnosis of lung cancer. There is complementarity in the combined detection of the level of TPS, NSE, CEA and beta(2)-MG. Their levels have close correlation with lung cancer, histological grades and lymphoid nodule metastasis.

  4. [Comparison of TPS, CEA, CYFRA21-1 and STNFR in diagnosis of lung cancer].

    PubMed

    Liao, Qiulin; Li, Lianhua; Chen, Mingsheng

    2005-08-20

    In recent years, new progress has been made in research of tumor markers. And namely tissue polypeptide specific antigen (TPS), cytokeratin 19-fragments (CYFRA21-1) and soluble tumor necrosis factor receptor (STNFR) are new tumor markers that have been used in clinical application. The aim of this study is to determine and compare the diagnostic value of 4 kinds of tumor markers, TPS, carcinoembryonic antigen (CEA), CYFRA21-1 and STNFR in patients with lung cancer. The serum levels of TPS, CEA, CYFRA21-1 and STNFR were determined in 72 patients with lung cancer, 54 patients with pulmonary benign diseases and 32 healthy adults by enzyme-linked immunosorbent assay (ELISA). The levels of the four tumor markers in lung cancer group were significantly higher than those in benign disease group (P < 0.005) and healthy control group (P < 0.001). Among the four markers, STNFR had the highest sensitivity (81.9%), CYFRA21-1 had the highest specificity (91.5%) and TPS had the highest accuracy (83.5%). TPS, CYFRA21-1 and STNFR can be used as very useful and sensitive tumor markers in the diagnosis of lung cancer, in which CYFRA21-1 may be the most useful tumor marker for clinical application.

  5. Controlling Au Nanorod Dispersion in Thin Film Polymer Blends

    NASA Astrophysics Data System (ADS)

    Hore, Michael J. A.; Composto, Russell J.

    2012-02-01

    Dispersion of Au nanorods (Au NRs) in polymer thin films is studied using a combination of experimental and theoretical techniques. Here, we incorporate small volume fractions of polystyrene-functionalized Au NRs (φrod 0.05) into polystyrene (PS) thin films. By controlling the ratio of the brush length (N) to that of the matrix polymers (P), we can selectively obtain dispersed or aggregated Au NR structures in the PS-Au(N):PS(P) films. A dispersion map of these structures allows one to choose N and P to obtain either uniformly dispersed Au NRs or aggregates of closely packed, side-by-side aligned Au NRs. Furthermore, by blending poly(2,6-dimethyl-p-phenylene oxide) (PPO) into the PS films, we demonstrate that the Au nanorod morphology can be further tuned by reducing depletion-attraction forces and promoting miscibility of the Au NRs. These predictable structures ultimately give rise to tunable optical absorption in the films resulting from surface plasmon resonance coupling between the Au NRs. Finally, self-consistent field theoretic (SCFT) calculations for both the PS-Au(N):PS(P) and PS-Au(N):PS(P):PPO systems provide insight into the PS brush structure, and allow us to interpret morphology and optical property results in terms of wet and dry PS brush states.

  6. Identified hadron transverse momentum spectra in Au+Au collisions at sNN=62.4 GeV

    NASA Astrophysics Data System (ADS)

    Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Busza, W.; Carroll, A.; Chai, Z.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Halliwell, C.; Hamblen, J.; Hauer, M.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Reed, C.; Roland, C.; Roland, G.; Sagerer, J.; Seals, H.; Sedykh, I.; Smith, C. E.; Stankiewicz, M. A.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tonjes, M. B.; Trzupek, A.; Vale, C.; Nieuwenhuizen, G. J. Van; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Wenger, E.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wysłouch, B.

    2007-02-01

    Transverse momentum spectra of pions, kaons, protons, and antiprotons from Au+Au collisions at sNN = 62.4 GeV have been measured by the PHOBOS experiment at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory. The identification of particles relies on three different methods: low momentum particles stopping in the first detector layers; the specific energy loss (dE/dx) in the silicon spectrometer, and time-of-flight measurement. These methods cover the transverse momentum ranges 0.03 0.2, 0.2 1.0, and 0.5 3.0 GeV/c, respectively. Baryons are found to have substantially harder transverse momentum spectra than mesons. The pT region in which the proton to pion ratio reaches unity in central Au+Au collisions at sNN = 62.4 GeV fits into a smooth trend as a function of collision energy. At low transverse mass, the spectra of various species exhibit a significant deviation from transverse mass scaling. The observed particle yields at very low pT are comparable to extrapolations from higher pT for kaons, protons and antiprotons. By comparing our results to Au+Au collisions at sNN = 200 GeV, we conclude that the net proton yield at midrapidity is proportional to the number of participant nucleons in the collision.

  7. Parameterization and study of elliptic flow coefficient for Au+Au and Cu+Cu collisions at RHIC energy 200 GeV/A

    NASA Astrophysics Data System (ADS)

    Kumar, Somani Ajit; Bright, Keswani; Sudhir, Bhardwaj; Ashish, Agnihotri

    2018-05-01

    Elliptic flow coefficient is important observable in search of Quark Gluon Plasma. The variation of elliptic flow coefficient with centrality were studied using events generated by AMPT (Default) for Au+Au and Cu+Cu collisions at center of mass energy of 200 GeV/A. We compared the simulated data results with RHIC-PHENIX experimental results and found close agreement between them. The study of the variation of the v2 for Au+Au and Cu+Cu was parameterized by fitting. We proposed a new formula to predict the expected value of v2 at particular centrality for Au+Au or Cu+Cu at 200 GeV/A.

  8. Atomic and electronic structures of Si(1 1 1)-(√3 x √3)R30°-Au and (6 × 6)-Au surfaces.

    PubMed

    Patterson, C H

    2015-12-02

    Si(1 1 1)-Au surfaces with around one monolayer of Au exhibit many ordered structures and structures containing disordered domain walls. Hybrid density functional theory (DFT) calculations presented here reveal the origin of these complex structures and tendency to form domain walls. The conjugate honeycomb chain trimer (CHCT) structure of the [Formula: see text]-Au phase contains Si atoms with non-bonding surface states which can bind Au atoms in pairs in interstices of the CHCT structure and make this surface metallic. Si adatoms adsorbed on the [Formula: see text]-Au surface induce a gapped surface through interaction with the non-bonding states. Adsorption of extra Au atoms in interstitial sites of the [Formula: see text]-Au surface is stabilized by interaction with the non-bonding orbitals and leads to higher coverage ordered structures including the [Formula: see text]-Au phase. Extra Au atoms bound in interstitial sites of the [Formula: see text]-Au surface result in top layer Si atoms with an SiAu4 butterfly wing configuration. The structure of a [Formula: see text]-Au phase, whose in-plane top atomic layer positions were previously determined by an electron holography technique (Grozea et al 1998 Surf. Sci. 418 32), is calculated using total energy minimization. The Patterson function for this structure is calculated and is in good agreement with data from an in-plane x-ray diffraction study (Dornisch et al 1991 Phys. Rev. B 44 11221). Filled and empty state scanning tunneling microscopy (STM) images are calculated for domain walls and the [Formula: see text]-Au structure. The [Formula: see text]-Au phase is 2D chiral and this is evident in computed and actual STM images. [Formula: see text]-Au and domain wall structures contain the SiAu4 motif with a butterfly wing shape. Chemical bonding within the Si-Au top layers of the [Formula: see text]-Au and [Formula: see text]-Au surfaces is analyzed and an explanation for the SiAu4 motif structure is given.

  9. CO oxidation on Alsbnd Au nano-composite systems

    NASA Astrophysics Data System (ADS)

    Rajesh, C.; Majumder, C.

    2018-03-01

    Using first principles method we report the CO oxidation behaviour of Alsbnd Au nano-composites in three different size ranges: Al6Au8, Al13Au42 and a periodic slab of Alsbnd Au(1 1 1) surface. The clusters prefer enclosed structures with alternating arrangement of Al and Au atoms, maximising Auδ-sbnd Alδ+ bonds. Charge distribution analysis suggests the charge transfer from Al to Au atoms, corroborated by the red shift in the density of states spectrum. Further, CO oxidation on these nano-composite systems was investigated through both Eley - Rideal and Langmuir Hinshelwood mechanism. While, these clusters interact with O2 non-dissociatively with an elongation of the Osbnd O bond, further interaction with CO led to formation of CO2 spontaneously. On contrary, the CO2 evolution by co-adsorption of O2 and CO molecules has a transition state barrier. On the basis of the results it is inferred that nano-composite material of Alsbnd Au shows significant promise toward effective oxidative catalysis.

  10. Comparison of the Effects of Magnetic Field on Low Noise MoAu and TiAu TES Bolometers

    NASA Astrophysics Data System (ADS)

    Hijmering, R. A.; Khosropanah, P.; Ridder, M.; Gao, J. R.; Hoevers, H.; Jackson, B.; Goldie, D.; Withington, S.; Kozorezov, A. G.

    2014-08-01

    Recently we have reported on the effects of magnetic field on our low noise (NEP = 4 W/Hz) [1] TiAu TES bolometers that are being developed at SRON for the SAFARI FIR Imaging Spectrometer on SPICA telescope that will be operated in three different wavelength bands: S-band for 30-60 , M-band for 60-110 and L-band for 110-210 . The arrays for the S- and M- band will be based on TiAu TES bolometer arrays, developed by SRON. The L-band array will be based on a MoAu TES bolometer developed by University of Cambridge. We have investigated the effect of the magnetic field on the current, responsivity, speed and critical current for both the TiAu and MoAu TES bolometers in our high accuracy magnetic field set-up. A clear difference in weak link behavior is observed between the two types of TES bolometers in both strength of the effect and period of the oscillations.

  11. Lateral spreading of Au contacts on InP

    NASA Technical Reports Server (NTRS)

    Fatemi, Navid S.; Weizer, Victor G.

    1990-01-01

    The contact spreading phenomenon observed when small area Au contacts on InP are annealed at temperatures above about 400 C was investigated. It was found that the rapid lateral expansion of the contact metallization which consumes large quantities of InP during growth is closely related to the third stage in the series of solid state reactions that occur between InP and Au, i.e., to the Au3In-to-Au9In4 transition. Detailed descriptions are presented of both the spreading process and the Au3In-to-Au9In4 transition along with arguments that the two processes are manifestations of the same basic phenomenon.

  12. Scaling Properties of Proton and Antiproton Production in (sNN)=200 GeV Au+Au Collisions

    NASA Astrophysics Data System (ADS)

    Adler, S. S.; Afanasiev, S.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Alexander, J.; Amirikas, R.; Aphecetche, L.; Aronson, S. H.; Averbeck, R.; Awes, T. C.; Azmoun, R.; Babintsev, V.; Baldisseri, A.; Barish, K. N.; Barnes, P. D.; Bassalleck, B.; Bathe, S.; Batsouli, S.; Baublis, V.; Bazilevsky, A.; Belikov, S.; Berdnikov, Y.; Bhagavatula, S.; Boissevain, J. G.; Borel, H.; Borenstein, S.; Brooks, M. L.; Brown, D. S.; Bruner, N.; Bucher, D.; Buesching, H.; Bumazhnov, V.; Bunce, G.; Burward-Hoy, J. M.; Butsyk, S.; Camard, X.; Chai, J.-S.; Chand, P.; Chang, W. C.; Chernichenko, S.; Chi, C. Y.; Chiba, J.; Chiu, M.; Choi, I. J.; Choi, J.; Choudhury, R. K.; Chujo, T.; Cianciolo, V.; Cobigo, Y.; Cole, B. A.; Constantin, P.; D'Enterria, D. G.; David, G.; Delagrange, H.; Denisov, A.; Deshpande, A.; Desmond, E. J.; Dietzsch, O.; Drapier, O.; Drees, A.; Du Rietz, R.; Durum, A.; Dutta, D.; Efremenko, Y. V.; El Chenawi, K.; Enokizono, A.; En'yo, H.; Esumi, S.; Ewell, L.; Fields, D. E.; Fleuret, F.; Fokin, S. L.; Fox, B. D.; Fraenkel, Z.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fung, S.-Y.; Garpman, S.; Ghosh, T. K.; Glenn, A.; Gogiberidze, G.; Gonin, M.; Gosset, J.; Goto, Y.; Granier de Cassagnac, R.; Grau, N.; Greene, S. V.; Grosse Perdekamp, G.; Guryn, W.; Gustafsson, H.-Å.; Hachiya, T.; Haggerty, J. S.; Hamagaki, H.; Hansen, A. G.; Hartouni, E. P.; Harvey, M.; Hayano, R.; He, X.; Heffner, M.; Hemmick, T. K.; Heuser, J. M.; Hibino, M.; Hill, J. C.; Holzmann, W.; Homma, K.; Hong, B.; Hoover, A.; Ichihara, T.; Ikonnikov, V. V.; Imai, K.; Isenhower, L. D.; Ishihara, M.; Issah, M.; Isupov, A.; Jacak, B. V.; Jang, W. Y.; Jeong, Y.; Jia, J.; Jinnouchi, O.; Johnson, B. M.; Johnson, S. C.; Joo, K. S.; Jouan, D.; Kametani, S.; Kamihara, N.; Kang, J. H.; Kapoor, S. S.; Katou, K.; Kelly, S.; Khachaturov, B.; Khanzadeev, A.; Kikuchi, J.; Kim, D. H.; Kim, D. J.; Kim, D. W.; Kim, E.; Kim, G.-B.; Kim, H. J.; Kistenev, E.; Kiyomichi, A.; Kiyoyama, K.; Klein-Boesing, C.; Kobayashi, H.; Kochenda, L.; Kochetkov, V.; Koehler, D.; Kohama, T.; Kopytine, M.; Kotchetkov, D.; Kozlov, A.; Kroon, P. J.; Kuberg, C. H.; Kurita, K.; Kuroki, Y.; Kweon, M. J.; Kwon, Y.; Kyle, G. S.; Lacey, R.; Ladygin, V.; Lajoie, J. G.; Lebedev, A.; Leckey, S.; Lee, D. M.; Lee, S.; Leitch, M. J.; Li, X. H.; Lim, H.; Litvinenko, A.; Liu, M. X.; Liu, Y.; Maguire, C. F.; Makdisi, Y. I.; Malakhov, A.; Manko, V. I.; Mao, Y.; Martinez, G.; Marx, M. D.; Masui, H.; Matathias, F.; Matsumoto, T.; McGaughey, P. L.; Melnikov, E.; Messer, F.; Miake, Y.; Milan, J.; Miller, T. E.; Milov, A.; Mioduszewski, S.; Mischke, R. E.; Mishra, G. C.; Mitchell, J. T.; Mohanty, A. K.; Morrison, D. P.; Moss, J. M.; Mühlbacher, F.; Mukhopadhyay, D.; Muniruzzaman, M.; Murata, J.; Nagamiya, S.; Nagle, J. L.; Nakamura, T.; Nandi, B. K.; Nara, M.; Newby, J.; Nilsson, P.; Nyanin, A. S.; Nystrand, J.; O'Brien, E.; Ogilvie, C. A.; Ohnishi, H.; Ojha, I. D.; Okada, K.; Ono, M.; Onuchin, V.; Oskarsson, A.; Otterlund, I.; Oyama, K.; Ozawa, K.; Pal, D.; Palounek, A. P.; Pantuev, V. S.; Papavassiliou, V.; Park, J.; Parmar, A.; Pate, S. F.; Peitzmann, T.; Peng, J.-C.; Peresedov, V.; Pinkenburg, C.; Pisani, R. P.; Plasil, F.; Purschke, M. L.; Purwar, A.; Rak, J.; Ravinovich, I.; Read, K. F.; Reuter, M.; Reygers, K.; Riabov, V.; Riabov, Y.; Roche, G.; Romana, A.; Rosati, M.; Rosnet, P.; Ryu, S. S.; Sadler, M. E.; Saito, N.; Sakaguchi, T.; Sakai, M.; Sakai, S.; Samsonov, V.; Sanfratello, L.; Santo, R.; Sato, H. D.; Sato, S.; Sawada, S.; Schutz, Y.; Semenov, V.; Seto, R.; Shaw, M. R.; Shea, T. K.; Shibata, T.-A.; Shigaki, K.; Shiina, T.; Silva, C. L.; Silvermyr, D.; Sim, K. S.; Singh, C. P.; Singh, V.; Sivertz, M.; Soldatov, A.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Sourikova, I. V.; Staley, F.; Stankus, P. W.; Stenlund, E.; Stepanov, M.; Ster, A.; Stoll, S. P.; Sugitate, T.; Sullivan, J. P.; Takagui, E. M.; Taketani, A.; Tamai, M.; Tanaka, K. H.; Tanaka, Y.; Tanida, K.; Tannenbaum, M. J.; Tarján, P.; Tepe, J. D.; Thomas, T. L.; Tojo, J.; Torii, H.; Towell, R. S.; Tserruya, I.; Tsuruoka, H.; Tuli, S. K.; Tydesjö, H.; Tyurin, N.; van Hecke, H. W.; Velkovska, J.; Velkovsky, M.; Villatte, L.; Vinogradov, A. A.; Volkov, M. A.; Vznuzdaev, E.; Wang, X. R.; Watanabe, Y.; White, S. N.; Wohn, F. K.; Woody, C. L.; Xie, W.; Yang, Y.; Yanovich, A.; Yokkaichi, S.; Young, G. R.; Yushmanov, I. E.; Zajc, W. A.; Zhang, C.; Zhou, S.; Zolin, L.

    2003-10-01

    We report on the yield of protons and antiprotons, as a function of centrality and transverse momentum, in Au+Au collisions at (sNN)=200 GeV measured at midrapidity by the PHENIX experiment at the BNL Relativistic Heavy Ion Collider. In central collisions at intermediate transverse momenta (1.5Au+Au, p+p, and e+e- collisions. This enhancement is limited to pT<5 GeV/c as deduced from the ratio of charged hadrons to π0 measured in the range 1.5

  13. X-ray Absorption Spectroscopy Combined with Time-Dependent Density Functional Theory Elucidates Differential Substitution Pathways of Au(I) and Au(III) with Zinc Fingers.

    PubMed

    Abbehausen, Camilla; de Paiva, Raphael Enoque Ferraz; Bjornsson, Ragnar; Gomes, Saulo Quintana; Du, Zhifeng; Corbi, Pedro Paulo; Lima, Frederico Alves; Farrell, Nicholas

    2018-01-02

    A combination of two elements' (Au, Zn) X-ray absorption spectroscopy (XAS) and time-dependent density functional theory (TD-DFT) allowed the elucidation of differential substitution pathways of Au(I) and Au(III) compounds reacting with biologically relevant zinc fingers (ZnFs). Gold L 3 -edge XAS probed the interaction of gold and the C-terminal Cys 2 HisCys finger of the HIV-1 nucleocapsid protein NCp7, and the Cys 2 His 2 human transcription factor Sp1. The use of model compounds helped assign oxidation states and the identity of the gold-bound ligands. The computational studies accurately reproduced the experimental XAS spectra and allowed the proposition of structural models for the interaction products at early time points. The direct electrophilic attack on the ZnF by the highly thiophilic Au(I) resulted in a linear P-Au-Cys coordination sphere after zinc ejection whereas for the Sp1, loss of PEt 3 results in linear Cys-Au-Cys or Cys-Au-His arrangements. Reactions with Au(III) compounds, on the other hand, showed multiple binding modes. Prompt reaction between [AuCl(dien)] 2+ and [Au(dien)(DMAP)] 3+ with Sp1 showed a partially reduced Au center and a final linear His-Au-His coordination. Differently, in the presence of NCp7, [AuCl(dien)] 2+ readily reduces to Au(I) and changes from square-planar to linear geometry with Cys-Au-His coordination, while [Au(dien)(DMAP)] 3+ initially maintains its Au(III) oxidation state and square-planar geometry and the same first coordination sphere. The latter is the first observation of a "noncovalent" interaction of a Au(III) complex with a zinc finger and confirms early hypotheses that stabilization of Au(III) occurs with N-donor ligands. Modification of the zinc coordination sphere, suggesting full or partial zinc ejection, is observed in all cases, and for [Au(dien)(DMAP)] 3+ this represents a novel mechanism for nucleocapsid inactivation. The combination of XAS and TD-DFT presents the first direct experimental

  14. Evidence of significant covalent bonding in Au(CN)(2)(-).

    PubMed

    Wang, Xue-Bin; Wang, Yi-Lei; Yang, Jie; Xing, Xiao-Peng; Li, Jun; Wang, Lai-Sheng

    2009-11-18

    The Au(CN)(2)(-) ion is the most stable Au compound known for centuries, yet a detailed understanding of its chemical bonding is still lacking. Here we report direct experimental evidence of significant covalent bonding character in the Au-C bonds in Au(CN)(2)(-) using photoelectron spectroscopy and comparisons with its lighter congeners, Ag(CN)(2)(-) and Cu(CN)(2)(-). Vibrational progressions in the Au-C stretching mode were observed for all detachment transitions for Au(CN)(2)(-), in contrast to the atomic-like transitions for Cu(CN)(2)(-), revealing the Au-C covalent bonding character. In addition, rich electronic structural information was obtained for Au(CN)(2)(-) by employing 118 nm detachment photons. Density functional theory and high-level ab initio calculations were carried out to understand the photoelectron spectra and obtain insight into the nature of the chemical bonding in the M(CN)(2)(-) complexes. Significant covalent character in the Au-C bonding due to the strong relativistic effects was revealed in Au(CN)(2)(-), consistent with its high stability.

  15. Au13(8e): A secondary block for describing a special group of liganded gold clusters containing icosahedral Au13 motifs

    NASA Astrophysics Data System (ADS)

    Xu, Wen Wu; Zeng, Xiao Cheng; Gao, Yi

    2017-05-01

    A grand unified model (GUM) has been proposed recently to understand structure anatomy and evolution of liganded gold clusters. In this work, besides the two types of elementary blocks (triangular Au3(2e) and tetrahedral Au4(2e)), we introduce a secondary block, namely, the icosahedral Au13 with 8e valence electrons, noted as Au13(8e). Using this secondary block, structural anatomy and evolution of a special group of liganded gold nanoclusters containing icosahedral Au13 motifs can be conveniently analyzed. In addition, a new ligand-protected cluster Au49(PR3)10(SR)15Cl2 is predicted to exhibit high chemical and thermal stability, suggesting likelihood of its synthesis in the laboratory.

  16. Space cryogenics at CEA-SBT

    NASA Astrophysics Data System (ADS)

    Duband, Lionel; Charles, Ivan; Duval, Jean-Marc; Ercolani, Eric; Gully, Philippe; Luchier, Nicolas; Prouve, Thomas; Thibault, Pierre

    2017-11-01

    The "Service des Basses Températures" (SBT) of CEA Grenoble has been involved in space cryogenics for over 20 years now. In fact a dedicated laboratory was created within SBT to carry out these developments, the "Cryocoolers and Space Cryogenics" group, which comprises about 20 persons as of today. Various cryocoolers have been developed in the past and our fields of activity focus now on four main technologies: sorption coolers, multistage pulse tubes, adiabatic demagnetization refrigerators (ADR), and cryogenic loop heat pipes. In addition work on two new concepts for ground based dilution refrigerators is also ongoing. Finally developments on various key technologies such as the heat switches, the suspension or structural systems are also carried out. These developments are mainly funded by the European Space Agency (ESA) or by the Centre National d'Etudes Spatiales (CNES). For most of these systems the common feature is the absence of any moving parts or any friction, which guarantees a very good reliability and make them very good candidates for space borne instruments requiring cryogenic temperatures. In this paper we give an overview of these developments with a particular focus on the sub Kelvin coolers. Based on the HERSCHEL heritage for which we developed the flight sorption coolers, we are now proposing an original concept featuring the association of a 300 mK sorption unit with a miniature adiabatic demagnetization refrigerator. This combination will allow to provide temperature as low as 50 mK with a system weighting less than 5 kg. This development may have direct application for the XEUS and SPICA missions.

  17. Partager : des technologies de pointe au service de la société

    ScienceCinema

    None

    2018-04-27

    Médecine, climatologie, métrologie et informatique, les techniques utilisées par le LHC trouvent déjà des répercussions dans d’autres domaines scientifiques. Utilisant des techniques inédites, la physique des particules en fait bénéficier la société toute entière.

  18. Au particle formation on the electron beam induced membrane

    NASA Astrophysics Data System (ADS)

    Choi, Seong Soo; Park, Myoung Jin; Han, Chul Hee; Oh, Sae-Joong; Kim, Sung-In; Park, Nam Kyou; Park, Doo-Jae; Choi, Soo Bong; Kim, Yong-Sang

    2017-02-01

    Recently the single molecules such as protein and deoxyribonucleic acid (DNA) have been successfully characterized by using a portable solidstate nanopore (MinION) with an electrical detection technique. However, there have been several reports about the high error rates of the fabricated nanopore device, possibly due to an electrical double layer formed inside the pore channel. The current DNA sequencing technology utilized is based on the optical detection method. In order to utilize the current optical detection technique, we will present the formation of the Au nano-pore with Au particle under the various electron beam irradiations. In order to provide the diffusion of Au atoms, a 2 keV electron beam irradiation has been performed During electron beam irradiations by using field emission scanning electron microscopy (FESEM), Au and C atoms would diffuse together and form the binary mixture membrane. Initially, the Au atoms diffused in the membrane are smaller than 1 nm, below the detection limit of the transmission electron microscopy (TEM), so that we are unable to observe the Au atoms in the formed membrane. However, after several months later, the Au atoms became larger and larger with expense of the smaller particles: Ostwald ripening. Furthermore, we also observe the Au crystalline lattice structure on the binary Au-C membrane. The formed Au crystalline lattice structures were constantly changing during electron beam imaging process due to Spinodal decomposition; the unstable thermodynamic system of Au-C binary membrane. The fabricated Au nanopore with an Au nanoparticle can be utilized as a single molecule nanobio sensor.

  19. Conductive Au nanowires regulated by silk fibroin nanofibers

    NASA Astrophysics Data System (ADS)

    Dong, Bo-Ju; Lu, Qiang

    2014-03-01

    Conductive Au-biopolymer composites have promising applications in tissue engineering such as nerve tissue regeneration. In this study, silk fibroin nanofibers were formed in aqueous solution by regulating silk self-assembly process and then used as template for Au nanowire fabrication. We performed the synthesis of Au seeds by repeating the seeding cycles for several times in order to increase the density of Au seeds on the nanofibers. After electroless plating, densely decorated Au seeds grew into irregularly shaped particles following silk nanofiber to fill the gaps between particles and finally form uniform continuous nanowires. The conductive property of the Au-silk fibroin nanowires was studied with current-voltage ( I-V) measurement. A typical ohmic behavior was observed, which highlighted their potential applications in nerve tissue regeneration.

  20. Identified baryon and meson distributions at large transverse momenta from Au + Au collisions at square root sNN=200 GeV.

    PubMed

    Abelev, B I; Aggarwal, M M; Ahammed, Z; Anderson, B D; Anderson, M; Arkhipkin, D; Averichev, G S; Bai, Y; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellingeri-Laurikainen, A; Bellwied, R; Benedosso, F; Bhardwaj, S; Bhasin, A; Bhati, A K; Bichsel, H; Bielcik, J; Bielcikova, J; Bland, L C; Blyth, S-L; Bonner, B E; Botje, M; Bouchet, J; Brandin, A V; Bravar, A; Burton, T P; Bystersky, M; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca Sánchez, M; Castillo, J; Catu, O; Cebra, D; Chajecki, Z; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, J H; Cheng, J; Cherney, M; Chikanian, A; Christie, W; Coffin, J P; Cormier, T M; Cosentino, M R; Cramer, J G; Crawford, H J; Das, D; Das, S; Dash, S; Daugherity, M; de Moura, M M; Dedovich, T G; Dephillips, M; Derevschikov, A A; Didenko, L; Dietel, T; Djawotho, P; Dogra, S M; Dong, W J; Dong, X; Draper, J E; Du, F; Dunin, V B; Dunlop, J C; Dutta Mazumdar, M R; Eckardt, V; Edwards, W R; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Estienne, M; Fachini, P; Fatemi, R; Fedorisin, J; Filip, P; Finch, E; Fine, V; Fisyak, Y; Fu, J; Gagliardi, C A; Gaillard, L; Ganti, M S; Ghazikhanian, V; Ghosh, P; Gonzalez, J E; Gorbunov, Y G; Gos, H; Grebenyuk, O; Grosnick, D; Guertin, S M; Guimaraes, K S F F; Gupta, N; Gutierrez, T D; Haag, B; Hallman, T J; Hamed, A; Harris, J W; He, W; Heinz, M; Henry, T W; Hepplemann, S; Hippolyte, B; Hirsch, A; Hjort, E; Hoffman, A M; Hoffmann, G W; Horner, M J; Huang, H Z; Huang, S L; Hughes, E W; Humanic, T J; Igo, G; Jacobs, P; Jacobs, W W; Jakl, P; Jia, F; Jiang, H; Jones, P G; Judd, E G; Kabana, S; Kang, K; Kapitan, J; Kaplan, M; Keane, D; Kechechyan, A; Khodyrev, V Yu; Kim, B C; Kiryluk, J; Kisiel, A; Kislov, E M; Klein, S R; Kocoloski, A; Koetke, D D; Kollegger, T; Kopytine, M; Kotchenda, L; Kouchpil, V; Kowalik, K L; Kramer, M; Kravtsov, P; Kravtsov, V I; Krueger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; Lapointe, S; Laue, F; Lauret, J; Lebedev, A; Lednicky, R; Lee, C-H; Lehocka, S; Levine, M J; Li, C; Li, Q; Li, Y; Lin, G; Lin, X; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, H; Liu, J; Liu, L; Liu, Z; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; Love, W A; Lu, Y; Ludlam, T; Lynn, D; Ma, G L; Ma, J G; Ma, Y G; Magestro, D; Mahapatra, D P; Majka, R; Mangotra, L K; Manweiler, R; Margetis, S; Markert, C; Martin, L; Matis, H S; Matulenko, Yu A; McClain, C J; McShane, T S; Melnick, Yu; Meschanin, A; Millane, J; Miller, M L; Minaev, N G; Mioduszewski, S; Mironov, C; Mischke, A; Mishra, D K; Mitchell, J; Mohanty, B; Molnar, L; Moore, C F; Morozov, D A; Munhoz, M G; Nandi, B K; Nattrass, C; Nayak, T K; Nelson, J M; Nepali, N S; Netrakanti, P K; Nogach, L V; Nurushev, S B; Odyniec, G; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Pachr, M; Pal, S K; Panebratsev, Y; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Peitzmann, T; Perevoztchikov, V; Perkins, C; Peryt, W; Phatak, S C; Picha, R; Planinic, M; Pluta, J; Poljak, N; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M; Potrebenikova, E; Potukuchi, B V K S; Prindle, D; Pruneau, C; Putschke, J; Rakness, G; Raniwala, R; Raniwala, S; Ray, R L; Razin, S V; Reinnarth, J; Relyea, D; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Rose, A; Roy, C; Ruan, L; Russcher, M J; Sahoo, R; Sakuma, T; Salur, S; Sandweiss, J; Sarsour, M; Sazhin, P S; Schambach, J; Scharenberg, R P; Schmitz, N; Seger, J; Selyuzhenkov, I; Seyboth, P; Shabetai, A; Shahaliev, E; Shao, M; Sharma, M; Shen, W Q; Shimanskiy, S S; Sichtermann, E P; Simon, F; Singaraju, R N; Smirnov, N; Snellings, R; Sood, G; Sorensen, P; Sowinski, J; Speltz, J; Spinka, H M; Srivastava, B; Stadnik, A; Stanislaus, T D S; Stock, R; Stolpovsky, A; Strikhanov, M; Stringfellow, B; Suaide, A A P; Subba, N L; Sugarbaker, E; Sumbera, M; Sun, Z; Surrow, B; Swanger, M; Symons, T J M; Szanto de Toledo, A; Tai, A; Takahashi, J; Tang, A H; Tarnowsky, T; Thein, D; Thomas, J H; Timmins, A R; Timoshenko, S; Tokarev, M; Trainor, T A; Trentalange, S; Tribble, R E; Tsai, O D; Ulery, J; Ullrich, T; Underwood, D G; Van Buren, G; van der Kolk, N; van Leeuwen, M; Vander Molen, A M; Varma, R; Vasilevski, I M; Vasiliev, A N; Vernet, R; Vigdor, S E; Viyogi, Y P; Vokal, S; Voloshin, S A; Waggoner, W T; Wang, F; Wang, G; Wang, J S; Wang, X L; Wang, Y; Watson, J W; Webb, J C; Westfall, G D; Wetzler, A; Whitten, C; Wieman, H; Wissink, S W; Witt, R; Wood, J; Wu, J; Xu, N; Xu, Q H; Xu, Z; Yepes, P; Yoo, I-K; Yurevich, V I; Zhan, W; Zhang, H; Zhang, W M; Zhang, Y; Zhang, Z P; Zhao, Y; Zhong, C; Zoulkarneev, R; Zoulkarneeva, Y; Zubarev, A N; Zuo, J X

    2006-10-13

    Transverse momentum spectra of pi+/-, p, and p up to 12 GeV/c at midrapidity in centrality selected Au + Au collisions at square root sNN=200 GeV are presented. In central Au + Au collisions, both pi +/- and p(p) show significant suppression with respect to binary scaling at pT approximately >4 GeV/c. Protons and antiprotons are less suppressed than pi+/-, in the range 1.5 approximately < pT approximately < 6 GeV/c. The pi-/pi+ and p/p ratios show at most a weak pT dependence and no significant centrality dependence. The p/pi ratios in central Au + Au collisions approach the values in p + p and d + Au collisions at pT approximately >5 GeV/c. The results at high pT indicate that the partonic sources of pi+/-, p, and p have similar energy loss when traversing the nuclear medium.

  1. Surface-enhanced Raman scattering study of carcinoembryonic antigen in serum from patients with colorectal cancers

    NASA Astrophysics Data System (ADS)

    Chen, Gang; Chen, Yanping; Zheng, Xiongwei; He, Cheng; Lu, Jianping; Feng, Shangyuan; Chen, Rong; Zeng, Haisan

    2013-12-01

    In this work, we developed a SERS platform for quantitative detection of carcinoembryonic antigen (CEA) in serum of patients with colorectal cancers. Anti-CEA-functionalized 4-mercaptobenzoic acid-labeled Au/Ag core-shell bimetallic nanoparticles were prepared first and then used to analyze CEA antigen solutions of different concentrations. A calibration curve was established in the range from 5 × 10-3 to 5 × 105 ng/mL. Finally, this new SERS probe was applied for quantitative detection of CEA in serum obtained from 26 colorectal cancer patients according to the calibration curve. The results were in good agreement with that obtained by electrochemical luminescence method, suggesting that SERS immunoassay has high sensitivity and specificity for CEA detection in serum. A detection limit of 5 pg/ml was achieved. This study demonstrated the feasibility and great potential for developing this new technology into a clinical tool for analysis of tumor markers in the blood.

  2. Synthesis of Au@Pt bimetallic nanoparticles with concave Au nanocuboids as seeds and their enhanced electrocatalytic properties in the ethanol oxidation reaction.

    PubMed

    Tan, Lingyu; Li, Lidong; Peng, Yi; Guo, Lin

    2015-12-18

    Herein, a new type of uniform and well-structured Au@Pt bimetallic nanoparticles (BNPs) with highly active concave Au nanocuboids (NCs) as seeds was successfully synthesized by using the classic seed-mediated method. Electrochemical measurements were conducted to demonstrate their greatly enhanced catalytic performance in the ethanol oxidation reaction (EOR). It was found that the electrochemical performance for Au@Pt BNPs with the concave Au NCs as seeds, which were enclosed by {611} high-index facets, could be seven times higher than that of the Au@Pt bimetallic nanoparticles with regular spherical Au NPs as seeds. Furthermore, our findings show that the morphology and electrocatalytic activity of the Au@Pt BNPs can be tuned simply by changing the compositional ratios of the growth solution. The lower the amount of H2PtCl6 used in the growth solution, the thinner the Pt shell grew, and the more high-index facets of concave Au NCs seeds were exposed in Au@Pt BNPs, leading to higher electrochemical activity. These as-prepared concave Au@Pt BNPs will open up new strategies for improving catalytic efficiency and reducing the use of the expensive and scarce resource of platinum in the ethanol oxidation reaction, and are potentially applicable as electrochemical catalysts for direct ethanol fuel cells.

  3. Synthesis of Au@Pt bimetallic nanoparticles with concave Au nanocuboids as seeds and their enhanced electrocatalytic properties in the ethanol oxidation reaction

    NASA Astrophysics Data System (ADS)

    Tan, Lingyu; Li, Lidong; Peng, Yi; Guo, Lin

    2015-12-01

    Herein, a new type of uniform and well-structured Au@Pt bimetallic nanoparticles (BNPs) with highly active concave Au nanocuboids (NCs) as seeds was successfully synthesized by using the classic seed-mediated method. Electrochemical measurements were conducted to demonstrate their greatly enhanced catalytic performance in the ethanol oxidation reaction (EOR). It was found that the electrochemical performance for Au@Pt BNPs with the concave Au NCs as seeds, which were enclosed by {611} high-index facets, could be seven times higher than that of the Au@Pt bimetallic nanoparticles with regular spherical Au NPs as seeds. Furthermore, our findings show that the morphology and electrocatalytic activity of the Au@Pt BNPs can be tuned simply by changing the compositional ratios of the growth solution. The lower the amount of H2PtCl6 used in the growth solution, the thinner the Pt shell grew, and the more high-index facets of concave Au NCs seeds were exposed in Au@Pt BNPs, leading to higher electrochemical activity. These as-prepared concave Au@Pt BNPs will open up new strategies for improving catalytic efficiency and reducing the use of the expensive and scarce resource of platinum in the ethanol oxidation reaction, and are potentially applicable as electrochemical catalysts for direct ethanol fuel cells.

  4. Stabilizing ultrasmall Au clusters for enhanced photoredox catalysis.

    PubMed

    Weng, Bo; Lu, Kang-Qiang; Tang, Zichao; Chen, Hao Ming; Xu, Yi-Jun

    2018-04-18

    Recently, loading ligand-protected gold (Au) clusters as visible light photosensitizers onto various supports for photoredox catalysis has attracted considerable attention. However, the efficient control of long-term photostability of Au clusters on the metal-support interface remains challenging. Herein, we report a simple and efficient method for enhancing the photostability of glutathione-protected Au clusters (Au GSH clusters) loaded on the surface of SiO 2 sphere by utilizing multifunctional branched poly-ethylenimine (BPEI) as a surface charge modifying, reducing and stabilizing agent. The sequential coating of thickness controlled TiO 2 shells can further significantly improve the photocatalytic efficiency, while such structurally designed core-shell SiO 2 -Au GSH clusters-BPEI@TiO 2 composites maintain high photostability during longtime light illumination conditions. This joint strategy via interfacial modification and composition engineering provides a facile guideline for stabilizing ultrasmall Au clusters and rational design of Au clusters-based composites with improved activity toward targeting applications in photoredox catalysis.

  5. Cross section of the 197Au(n,2n)196Au reaction

    NASA Astrophysics Data System (ADS)

    Kalamara, A.; Vlastou, R.; Kokkoris, M.; Diakaki, M.; Serris, M.; Patronis, N.; Axiotis, M.; Lagoyannis, A.

    2017-09-01

    The 197Au(n,2n)196Au reaction cross section has been measured at two energies, namely at 17.1 MeV and 20.9 MeV, by means of the activation technique, relative to the 27Al(n,α)24Na reference reaction cross section. Quasi-monoenergetic neutron beams were produced at the 5.5 MV Tandem T11/25 accelerator laboratory of NCSR "Demokritos", by means of the 3H(d,n)4He reaction, implementing a new Ti-tritiated target of ˜ 400 GBq activity. The induced γ-ray activity at the targets and reference foils has been measured with HPGe detectors. The cross section for the population of the second isomeric (12-) state m2 of 196Au was independently determined. Auxiliary Monte Carlo simulations were performed using the MCNP code. The present results are in agreement with previous experimental data and with theoretical calculations of the measured reaction cross sections, which were carried out with the use of the EMPIRE code.

  6. Mechanical properties and grindability of experimental Ti-Au alloys.

    PubMed

    Takahashi, Masatoshi; Kikuchi, Masafumi; Okuno, Osamu

    2004-06-01

    Experimental Ti-Au alloys (5, 10, 20 and 40 mass% Au) were made. Mechanical properties and grindability of the castings of the Ti-Au alloys were examined. As the concentration of gold increased to 20%, the yield strength and the tensile strength of the Ti-Au alloys became higher without markedly deteriorating their ductility. This higher strength can be explained by the solid-solution strengthening of the a titanium. The Ti-40%Au alloy became brittle because the intermetallic compound Ti3Au precipitated intensively near the grain boundaries. There was no significant difference in the grinding rate and grinding ratio among all the Ti-Au alloys and the pure titanium at any speed.

  7. Préface

    NASA Astrophysics Data System (ADS)

    Jörgen Stevefelt, Henri Bachau Et

    2003-06-01

    'impulsions attosecondes qui permettra d'explorer la matière à l'echelle de temps atomique. En même temps la caractérisation de ces impulsions nécessite la conception de techniques nouvelles d'analyse du signal aux temps ultra brefs.L'intéret particulier du colloque UVX est de réunir les communautés de scientifiques qui vont des chercheurs s'intéressant aux processus fondamentaux à ceux travaillant dans les domaines les plus appliqués, voire industriels. Une caractéristique marquante de notre discipline est la rapidité avec laquelle les progrès réalisés dans les laboratoires de recherche sont diffusés vers les applications industrielles. Il est donc important de maintenir un bon équilibre entre les recherches a caractères fondamental et appliqué dans les laboratoires.Nous tenons remercier les membres du comité d'organisation, le comité scientifique et les différents partenaires, institutionnels et industriels, qui par leur soutien ont permis que le colloque UVX puisse se dérouler. Ce colloque a été parrainé par les départements des Sciences Physiques et Mathématiques (SPM) et des Sciences pour l'Ingénieur (SPI) du CNRS, la Délégation Générale de l'Armement (DGA), le CEA DRECAM, le CEA DAM, le Conseil Géneral de Charente Maritime, l'Université de Bordeaux I, la Société Française d'optique, le Groupement de Recherche “SAXO" du CNRS et la société Air Liquide.

  8. First results on d+Au collisions from PHOBOS

    NASA Astrophysics Data System (ADS)

    Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Becker, B.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Harrington, A. S.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Lee, J. W.; Lin, W. T.; Manly, S.; Mignerey, A. C.; Noell, A.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Roland, C.; Roland, G.; Sagerer, J.; Sarin, P.; Sawicki, P.; Sedykh, I.; Skulski, W.; Smith, C. E.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Teng, R.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Veres, G. I.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.; Zhang, J.

    2004-02-01

    We have measured transverse momentum distributions of charged hadrons produced in d+Au collisions at √SNN = 200 GeV, in the range 0.25 < pT < 6.0 GeV/c. With increasing collision centrality, the yield at high transverse momenta increases more rapidly than the overall particle density, leading to a strong modification of the spectral shape. This change in spectral shape is qualitatively different from observations in Au+Au collisions at the same energy. The results provide important information for discriminating between different models for the suppression of high-pT hadrons observed in Au+Au collisions.

  9. Deep sub-threshold ϕ production in Au+Au collisions

    NASA Astrophysics Data System (ADS)

    Adamczewski-Musch, J.; Arnold, O.; Behnke, C.; Belounnas, A.; Belyaev, A.; Berger-Chen, J. C.; Biernat, J.; Blanco, A.; Blume, C.; Böhmer, M.; Bordalo, P.; Chernenko, S.; Chlad, L.; Deveaux, C.; Dreyer, J.; Dybczak, A.; Epple, E.; Fabbietti, L.; Fateev, O.; Filip, P.; Fonte, P.; Franco, C.; Friese, J.; Fröhlich, I.; Galatyuk, T.; Garzón, J. A.; Gernhäuser, R.; Golubeva, M.; Greifenhagen, R.; Guber, F.; Gumberidze, M.; Harabasz, S.; Heinz, T.; Hennino, T.; Hlavac, S.; Höhne, C.; Holzmann, R.; Ierusalimov, A.; Ivashkin, A.; Kämpfer, B.; Karavicheva, T.; Kardan, B.; Koenig, I.; Koenig, W.; Kolb, B. W.; Korcyl, G.; Kornakov, G.; Kotte, R.; Kühn, W.; Kugler, A.; Kunz, T.; Kurepin, A.; Kurilkin, A.; Kurilkin, P.; Ladygin, V.; Lalik, R.; Lapidus, K.; Lebedev, A.; Lopes, L.; Lorenz, M.; Mahmoud, T.; Maier, L.; Mangiarotti, A.; Markert, J.; Maurus, S.; Metag, V.; Michel, J.; Mihaylov, D. M.; Morozov, S.; Müntz, C.; Münzer, R.; Naumann, L.; Nowakowski, K. N.; Palka, M.; Parpottas, Y.; Pechenov, V.; Pechenova, O.; Petukhov, O.; Pietraszko, J.; Przygoda, W.; Ramos, S.; Ramstein, B.; Reshetin, A.; Rodriguez-Ramos, P.; Rosier, P.; Rost, A.; Sadovsky, A.; Salabura, P.; Scheib, T.; Schuldes, H.; Schwab, E.; Scozzi, F.; Seck, F.; Sellheim, P.; Siebenson, J.; Silva, L.; Sobolev, Yu. G.; Spataro, S.; Ströbele, H.; Stroth, J.; Strzempek, P.; Sturm, C.; Svoboda, O.; Szala, M.; Tlusty, P.; Traxler, M.; Tsertos, H.; Usenko, E.; Wagner, V.; Wendisch, C.; Wiebusch, M. G.; Wirth, J.; Zanevsky, Y.; Zumbruch, P.; Hades Collaboration

    2018-03-01

    We present data on charged kaons (K±) and ϕ mesons in Au(1.23A GeV)+Au collisions. It is the first simultaneous measurement of K- and ϕ mesons in central heavy-ion collisions below a kinetic beam energy of 10A GeV. The ϕ /K- multiplicity ratio is found to be surprisingly high with a value of 0.52 ± 0.16 and shows no dependence on the centrality of the collision. Consequently, the different slopes of the K+ and K- transverse-mass spectra can be explained solely by feed-down, which substantially softens the spectra of K- mesons. Hence, in contrast to the commonly adapted argumentation in literature, the different slopes do not necessarily imply diverging freeze-out temperatures of K+ and K- mesons caused by different couplings to baryons.

  10. Advanced uncooled infrared focal plane development at CEA/LETI

    NASA Astrophysics Data System (ADS)

    Tissot, Jean-Luc; Mottin, Eric; Martin, Jean-Luc; Yon, Jean-Jacques; Vilain, Michel

    2017-11-01

    LETI/LIR has been involved for a few year in the field of uncooled detectors and has chosen amorphous silicon for its microbolometer technology development. Uncooled IR detectors pave the way to reduced weight systems aboard satellites. The silicon compatibility of our thermometer is a key parameter which has enabled a very fast technology development and transfer to industry. This competitive technology is now able to provide a new approach for IR detectors for space applications. This paper presents the main characteristics of the CEA / LETI technology which is based on a monolithically integrated structure over a fully completed readout circuit from a commercially available 0.5 μm design rules CMOS line. The technology maturity will be illustrated by the results obtained at LETI/LIR and SOFRADIR on a 320 x 240 with a pitch of 45 μm. First improvement on device reliability and characterization results will be presented.

  11. K(892)* resonance production in Au+Au and p+p collisions at {radical}s{sub NN} = 200 GeV at RHIC

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Adams, J.; Aggarwal, M.M.; Ahammed, Z.

    2004-12-09

    The short-lived K(892)* resonance provides an efficient tool to probe properties of the hot and dense medium produced in relativistic heavy-ion collisions. We report measurements of K* in {radical}s{sub NN} = 200 GeV Au+Au and p+p collisions reconstructed via its hadronic decay channels K(892)*{sup 0} {yields} K{pi} and K(892)*{sup +-} {yields} K{sub S}{sup 0}{pi}{sup +-} using the STAR detector at RHIC. The K*{sup 0} mass has been studied as function of p{sub T} in minimum bias p + p and central Au+Au collisions. The K* p{sub T} spectra for minimum bias p + p interactions and for Au+Au collisions inmore » different centralities are presented. The K*/K ratios for all centralities in Au+Au collisions are found to be significantly lower than the ratio in minimum bias p + p collisions, indicating the importance of hadronic interactions between chemical and kinetic freeze-outs. The nuclear modification factor of K* at intermediate p{sub T} is similar to that of K{sub S}{sup 0}, but different from {Lambda}. This establishes a baryon-meson effect over a mass effect in the particle production at intermediate p{sub T} (2 < p{sub T} {le} 4 GeV/c). A significant non-zero K*{sup 0} elliptic flow (v{sub 2}) is observed in Au+Au collisions and compared to the K{sub S}{sup 0} and {Lambda} v{sub 2}.« less

  12. Rationalization of Au concentration and distribution in AuNi@Pt core-shell nanoparticles for oxygen reduction reaction

    DOE PAGES

    An, Wei; Liu, Ping

    2015-09-18

    Improving the activity and stability of Pt-based core–shell nanocatalysts for proton exchange membrane fuel cells while lowering Pt loading has been one of the big challenges in electrocatalysis. Here, using density functional theory, we report the effect of adding Au as the third element to enhance the durability and activity of Ni@Pt core–shell nanoparticles (NPs) during the oxygen reduction reaction (ORR). Our results show that the durability and activity of a Ni@Pt NP can be finely tuned by controlling Au concentration and distribution. For a NiAu@Pt NP, the durability can be greatly promoted by thermodynamically favorable segregation of Au tomore » replace the Pt atoms at vertex, edge, and (100) facets on the shell, while still keeping the ORR activity on the active Pt(111) shell as high as that of Ni@Pt nanoparticles. Such behavior strongly depends on a direct interaction with the Ni interlayer. The results not only highlight the importance of interplay between surface strain on the shell and the interlayer–shell interaction in determining the durability and activity but also provide guidance on how to maximize the usage of Au to optimize the performance of core–shell (Pt) nanoparticles. As a result, such understanding has allowed us to discover a novel NiAu@Pt nanocatalyst for the ORR.« less

  13. Ag@Au concave cuboctahedra: A unique probe for monitoring Au-catalyzed reduction and oxidation reactions by surface-enhanced Raman spectroscopy

    DOE PAGES

    Zhang, Jiawei; Winget, Sarah A.; Wu, Yiren; ...

    2016-01-26

    In this paper, we report a facile synthesis of Ag@Au concave cuboctahedra by titrating aqueous HAuCl4 into a suspension of Ag cuboctahedra in the presence of ascorbic acid (AA), NaOH, and poly(vinylpyrrolidone) (PVP) at room temperature. Initially, the Au atoms derived from the reduction of Au 3+ by AA are conformally deposited on the entire surface of a Ag cuboctahedron. Upon the formation of a complete Au shell, however, the subsequently formed Au atoms are preferentially deposited onto the Au{100} facets, resulting in the formation of a Ag@Au cuboctahedron with concave structures at the sites of {111} facets. The concavemore » cuboctahedra embrace excellent SERS activity that is more than 70-fold stronger than that of the original Ag cuboctahedra at an excitation wavelength of 785 nm. The concave cuboctahedra also exhibit remarkable stability in the presence of an oxidant such as H 2O 2 because of the protection by a complete Au shell. These two unique attributes enable in-situ SERS monitoring of the reduction of 4-nitrothiophenol (4-NTP) to 4-aminothiophenol (4-ATP) by NaBH4 through a 4,4'-dimercaptoazobenzene ( trans-DMAB) intermediate and the subsequent oxidation of 4-ATP back to trans-DMAB upon the introduction of H 2O 2.« less

  14. Ag@Au concave cuboctahedra: A unique probe for monitoring Au-catalyzed reduction and oxidation reactions by surface-enhanced Raman spectroscopy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhang, Jiawei; Winget, Sarah A.; Wu, Yiren

    In this paper, we report a facile synthesis of Ag@Au concave cuboctahedra by titrating aqueous HAuCl4 into a suspension of Ag cuboctahedra in the presence of ascorbic acid (AA), NaOH, and poly(vinylpyrrolidone) (PVP) at room temperature. Initially, the Au atoms derived from the reduction of Au 3+ by AA are conformally deposited on the entire surface of a Ag cuboctahedron. Upon the formation of a complete Au shell, however, the subsequently formed Au atoms are preferentially deposited onto the Au{100} facets, resulting in the formation of a Ag@Au cuboctahedron with concave structures at the sites of {111} facets. The concavemore » cuboctahedra embrace excellent SERS activity that is more than 70-fold stronger than that of the original Ag cuboctahedra at an excitation wavelength of 785 nm. The concave cuboctahedra also exhibit remarkable stability in the presence of an oxidant such as H 2O 2 because of the protection by a complete Au shell. These two unique attributes enable in-situ SERS monitoring of the reduction of 4-nitrothiophenol (4-NTP) to 4-aminothiophenol (4-ATP) by NaBH4 through a 4,4'-dimercaptoazobenzene ( trans-DMAB) intermediate and the subsequent oxidation of 4-ATP back to trans-DMAB upon the introduction of H 2O 2.« less

  15. The electric dipole moments in the ground states of gold oxide, AuO, and gold sulfide, AuS.

    PubMed

    Zhang, Ruohan; Yu, Yuanqin; Steimle, Timothy C; Cheng, Lan

    2017-02-14

    The B 2 Σ - - X 2 Π 3/2 (0,0) bands of a cold molecular beam sample of gold monoxide, AuO, and gold monosulfide, AuS, have been recorded at high resolution both field free and in the presence of a static electric field. The observed electric field induced splittings and shifts were analyzed to produce permanent electric dipole moments, μ→ el , of 2.94±0.06 D and 2.22±0.05 D for the X 2 Π 3/2 (v = 0) states of AuO and AuS, respectively. A molecular orbital correlation diagram is used to rationalize the trend in ground state μ→ el values for AuX (X = F, Cl, O, and S) molecules. The experimentally determined μ→ el are compared to those computed at the coupled-cluster singles and doubles (CCSD) level augmented with a perturbative inclusion of triple excitations (CCSD(T)) level of theory.

  16. Two Barium Gold Iodates: Syntheses, Structures, and Properties of Polar BaAu(IO3)5 and Nonpolar HBa4Au(IO3)12 Materials.

    PubMed

    Yang, Bing-Ping; Hu, Chun-Li; Mao, Fei-Fei; Xu, Xiang; Mao, Jiang-Gao

    2017-06-19

    Two new barium gold iodates, namely, BaAu(IO 3 ) 5 and HBa 4 Au(IO 3 ) 12 , have been prepared. BaAu(IO 3 ) 5 crystallizes in the polar space group Pca2 1 , whereas HBa 4 Au(IO 3 ) 12 crystallizes in the centrosymmetric space group P2 1 /c. BaAu(IO 3 ) 5 consists of unique polar [Au(IO 3 ) 4 ] - anions whose four iodate groups are located at both sides of the AuO 4 plane and the polarity points in the [001̅] direction. BaAu(IO 3 ) 5 displays strong second-harmonic-generation (SHG) effects about 0.6KTiOPO 4 (KTP) and is phase-matchable. Thermal properties, optical spectra analyses, and theoretical calculations are also reported.

  17. Exfoliation restacking route to Au nanoparticle-clay nanohybrids

    NASA Astrophysics Data System (ADS)

    Paek, Seung-Min; Jang, Jae-Up; Hwang, Seong-Ju; Choy, Jin-Ho

    2006-05-01

    A novel gold-pillared aluminosilicate (Au-PILC) were synthesized with positively charged gold nanoparticles capped by mercaptoammonium and exfoliated silicate layers. Gold nanoparticles were synthesized by NaBH4 reduction of AuCl4- in the presence of N,N,N-Trimethyl (11-mercaptoundecyl)ammonium (HS(CH2)11NMe3+) protecting ligand in an aqueous solution, and purified by dialysis. The resulting positively charged and water-soluble gold nanoparticles were hybridized with exfoliated silicate sheets by electrostatic interaction. The formation of Au clay hybrids could be easily confirmed by the powder X-ray diffraction with the increased basal spacing of clay upon insertion of Au nanoparticles. TEM image clearly revealed that the Au particles with an average size of 4 nm maintain their structure even after intercalation. The Au nanoparticles supported by clay matrix were found to be thermally more stable, suggesting that the Au nanoparticles were homogeneously protected with clay nanoplates. The present synthetic route could be further applicable to various hybrid systems between metal nanoparticles and clays.

  18. Template growth of Au, Ni and Ni–Au nanoclusters on hexagonal boron nitride/Rh(111): a combined STM, TPD and AES study

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wu, Fanglue; Huang, Dali; Yue, Yuan

    In this study, the template growth of Au, Ni, and Ni–Au bimetallic nanoclusters on hexagonal boron nitride/Rh(111), i.e. h-BN/Rh(111), was investigated via scanning tunneling microscopy (STM), temperature programmed-desorption (TPD), and Auger electron spectroscopy (AES). STM study shows that template growth of Au clusters on h-BN/Rh(111) forms mainly well-dispersed monolayer clusters. In contrast, Ni forms large multilayer clusters showing a relatively high diffusivity on h-BN/Rh(111) substrate. Ni–Au bimetallic clusters are effectively formed first by Au deposition followed by Ni deposition, with the Au clusters functioning as nucleation sites for the subsequently deposited Ni. Further structural analysis was carried out via TPDmore » and AES. The resulting TPD and AES data show the surface composition and charge transfer between Au and Ni of the bimetallic clusters. These results suggest that the h-BN/Rh(111) substrate represents a unique candidate for supporting Ni–Au bimetallic clusters in further catalytic reactions.« less

  19. Template growth of Au, Ni and Ni–Au nanoclusters on hexagonal boron nitride/Rh(111): a combined STM, TPD and AES study

    DOE PAGES

    Wu, Fanglue; Huang, Dali; Yue, Yuan; ...

    2017-09-12

    In this study, the template growth of Au, Ni, and Ni–Au bimetallic nanoclusters on hexagonal boron nitride/Rh(111), i.e. h-BN/Rh(111), was investigated via scanning tunneling microscopy (STM), temperature programmed-desorption (TPD), and Auger electron spectroscopy (AES). STM study shows that template growth of Au clusters on h-BN/Rh(111) forms mainly well-dispersed monolayer clusters. In contrast, Ni forms large multilayer clusters showing a relatively high diffusivity on h-BN/Rh(111) substrate. Ni–Au bimetallic clusters are effectively formed first by Au deposition followed by Ni deposition, with the Au clusters functioning as nucleation sites for the subsequently deposited Ni. Further structural analysis was carried out via TPDmore » and AES. The resulting TPD and AES data show the surface composition and charge transfer between Au and Ni of the bimetallic clusters. These results suggest that the h-BN/Rh(111) substrate represents a unique candidate for supporting Ni–Au bimetallic clusters in further catalytic reactions.« less

  20. Transformation of Au144(SCH2CH2Ph)60 to Au133(SPh-tBu)52 Nanomolecules: Theoretical and Experimental Study.

    PubMed

    Nimmala, Praneeth Reddy; Theivendran, Shevanuja; Barcaro, Giovanni; Sementa, Luca; Kumara, Chanaka; Jupally, Vijay Reddy; Apra, Edoardo; Stener, Mauro; Fortunelli, Alessandro; Dass, Amala

    2015-06-04

    Ultrastable gold nanomolecule Au144(SCH2CH2Ph)60 upon etching with excess tert-butylbenzenethiol undergoes a core-size conversion and compositional change to form an entirely new core of Au133(SPh-tBu)52. This conversion was studied using high-resolution electrospray mass spectrometry which shows that the core size conversion is initiated after 22 ligand exchanges, suggesting a relatively high stability of the Au144(SCH2CH2Ph)38(SPh-tBu)22 intermediate. The Au144 → Au133 core size conversion is surprisingly different from the Au144 → Au99 core conversion reported in the case of thiophenol, -SPh. Theoretical analysis and ab initio molecular dynamics simulations show that rigid p-tBu groups play a crucial role by reducing the cluster structural freedom, and protecting the cluster from adsorption of exogenous and reactive species, thus rationalizing the kinetic factors that stabilize the Au133 core size. This 144-atom to 133-atom nanomolecule's compositional change is reflected in optical spectroscopy and electrochemistry.

  1. Na8Au9.8(4)Ga7.2 and Na17Au5.87(2)Ga46.63: The diversity of pseudo 5-fold symmetries in the Na-Au-Ga system

    NASA Astrophysics Data System (ADS)

    Smetana, Volodymyr; Corbett, John D.; Miller, Gordon J.

    2013-11-01

    The Na-rich part (~30% Na) of the Na-Au-Ga system between NaAu2, NaGa4, and Na22Ga39 has been found to contain the ternary phases Na8Au9.8(4)Ga7.2 (I) and Na17Au5.87(2)Ga46.63 (II), according to the results of single crystal X-ray diffraction measurements. I is orthorhombic, Cmcm, a=5.3040(1), b=24.519(5), c=14.573(3) Å, and contains a network of clusters with local 5-fold symmetry along the a-axis. Such clusters are frequent building units in decagonal quasicrystals and their approximants. II is rhombohedral, R3¯m, a=16.325(2), c=35.242(7) Å, and contains building blocks that are structurally identical to the Bergman-type clusters as well as fused icosahedral units known with active metals, triels and late transition elements. II also contains a polycationic network with elements of the clathrate V type structure. Tight-binding electronic structure calculations using linear muffin-tin-orbital (LMTO) methods on idealized models of I and II indicate that both compounds are metallic with evident pseudogaps at the corresponding Fermi levels. The overall Hamilton bond populations are generally dominated by Au-Ga and Au-Au bonds in I and by Ga-Ga bonds in II; moreover, the Na-Au and Na-Ga contributions in I are unexpectedly large, ~20% of the total. A similar involvement of sodium in covalent bonding has also been found in the electron-richer i-Na13Au12Ga15 quasicrystal approximant.

  2. First-principles study of Au-decorated carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Ju, Weiwei; Li, Tongwei; Zhou, Qingxiao; Li, Haisheng; Li, Xiaohong

    2018-07-01

    The electronic structures and spin-orbit (SO) coupling of carbon nanotubes with adsorbed Au atoms are investigated based on density functional theory. Three kinds of zigzag single-walled CNT (8,0), (10,0) and (12,0) are selected. The Au atoms prefer to adsorb on the top of C atoms. The adsorption of Au atoms can introduce impurity states in the band gap, modifying the electronic properties of systems. Furthermore, the influence of SO coupling on these impurity states is also explored. Considerable SO splitting (∼130 meV) can be obtained. We find that the SO splitting decreases with the increase of the concentration of Au atoms, which can be ascribed to the interaction between Au atoms, suppressing the SO splitting. Our work provides imperative understanding on the electronic properties and SO coupling effect in Au-decorated CNTs.

  3. Transverse-momentum dependent modification of dynamic texture in central Au+Au collisions at sqrt(sNN) = 200 GeV

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Adams, J.; Aggarwal, M.M.; Ahammed, Z.

    2005-01-10

    Correlations in the hadron distributions produced in relativistic Au+Au collisions are studied in the discrete wavelet expansion method. The analysis is performed in the space of pseudorapidity (|{eta}| {le} 1) and azimuth (full 2{pi}) in bins of transverse momentum (p{sub t}) from 0.14 {le} p{sub t} {le} 2.1 GeV/c. In peripheral Au+Au collisions a correlation structure ascribed to minijet fragmentation is observed. It evolves with collision centrality and p{sub t} in a way not seen before which suggests strong dissipation of minijet fragmentation in the longitudinally-expanding medium.

  4. Tuning SPT-3G Transition-Edge-Sensor Electrical Properties with a Four-Layer Ti-Au-Ti-Au Thin-Film Stack

    NASA Astrophysics Data System (ADS)

    Carter, F. W.; Ade, P. A. R.; Ahmed, Z.; Anderson, A. J.; Austermann, J. E.; Avva, J. S.; Thakur, R. Basu; Bender, A. N.; Benson, B. A.; Carlstrom, J. E.; Cecil, T.; Chang, C. L.; Cliche, J. F.; Cukierman, A.; Denison, E. V.; de Haan, T.; Ding, J.; Divan, R.; Dobbs, M. A.; Dutcher, D.; Everett, W.; Foster, A.; Gannon, R. N.; Gilbert, A.; Groh, J. C.; Halverson, N. W.; Harke-Hosemann, A. H.; Harrington, N. L.; Henning, J. W.; Hilton, G. C.; Holzapfel, W. L.; Huang, N.; Irwin, K. D.; Jeong, O. B.; Jonas, M.; Khaire, T.; Kofman, A. M.; Korman, M.; Kubik, D.; Kuhlmann, S.; Kuo, C. L.; Kutepova, V.; Lee, A. T.; Lowitz, A. E.; Meyer, S. S.; Michalik, D.; Miller, C. S.; Montgomery, J.; Nadolski, A.; Natoli, T.; Nguyen, H.; Noble, G. I.; Novosad, V.; Padin, S.; Pan, Z.; Pearson, J.; Posada, C. M.; Rahlin, A.; Ruhl, J. E.; Saunders, L. J.; Sayre, J. T.; Shirley, I.; Shirokoff, E.; Smecher, G.; Sobrin, J. A.; Stan, L.; Stark, A. A.; Story, K. T.; Suzuki, A.; Tang, Q. Y.; Thompson, K. L.; Tucker, C.; Vale, L. R.; Vanderlinde, K.; Vieira, J. D.; Wang, G.; Whitehorn, N.; Yefremenko, V.; Yoon, K. W.; Young, M. R.

    2018-04-01

    We have developed superconducting Ti transition-edge sensors with Au protection layers on the top and bottom for the South Pole Telescope's third-generation receiver (a cosmic microwave background polarimeter, due to be upgraded this austral summer of 2017/2018). The base Au layer (deposited on a thin Ti glue layer) isolates the Ti from any substrate effects; the top Au layer protects the Ti from oxidation during processing and subsequent use of the sensors. We control the transition temperature and normal resistance of the sensors by varying the sensor width and the relative thicknesses of the Ti and Au layers. The transition temperature is roughly six times more sensitive to the thickness of the base Au layer than to that of the top Au layer. The normal resistance is inversely proportional to sensor width for any given film configuration. For widths greater than five micrometers, the critical temperature is independent of width.

  5. Centrality and collision system dependence of antiproton production from p+A to Au+Au collisions at AGS energies

    NASA Technical Reports Server (NTRS)

    Sako, H.; Ahle, L.; Akiba, Y.; Ashktorab, K.; Baker, M. D.; Beavis, D.; Britt, H. C.; Chang, J.; Chasman, C.; Chen, Z.; hide

    1997-01-01

    Antiproton production in heavy ion collisions reflects subtle interplay between initial production and absorption by nucleons. Because the AGS energies (10--20 A(center-dot)GeV/c) are close to the antiproton production threshold, antiproton may be sensitive to cooperative processes such as QGP and hadronic multi-step processes. On the other hand, antiproton has been proposed as a probe of baryon density due to large N(anti N) annihilation cross sections. Cascade models predict the maximum baryon density reaches about 10 times the normal nucleus density in central Au+Au collisions, where the strong antiproton absorption is expected. In this paper, the authors show systematic studies of antiproton production from p+A to Au+Au collisions.

  6. Distributions of charged hadrons associated with high transverse momentum particles in pp and Au+Au collisions at sqrt[sNN]=200 GeV.

    PubMed

    Adams, J; Adler, C; Aggarwal, M M; Ahammed, Z; Amonett, J; Anderson, B D; Arkhipkin, D; Averichev, G S; Badyal, S K; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellwied, R; Berger, J; Bezverkhny, B I; Bhardwaj, S; Bhati, A K; Bichsel, H; Billmeier, A; Bland, L C; Blyth, C O; Bonner, B E; Botje, M; Boucham, A; Brandin, A; Bravar, A; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca Sánchez, M; Carroll, J; Castillo, J; Cebra, D; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, Y; Chernenko, S P; Cherney, M; Chikanian, A; Christie, W; Coffin, J P; Cormier, T M; Cramer, J G; Crawford, H J; Das, D; Das, S; Derevschikov, A A; Didenko, L; Dietel, T; Dong, W J; Dong, X; Draper, J E; Du, F; Dubey, A K; Dunin, V B; Dunlop, J C; Dutta Majumdar, M R; Eckardt, V; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Estienne, M; Fachini, P; Faine, V; Faivre, J; Fatemi, R; Filimonov, K; Filip, P; Finch, E; Fisyak, Y; Flierl, D; Foley, K J; Fu, J; Gagliardi, C A; Gagunashvili, N; Gans, J; Ganti, M S; Gaudichet, L; Geurts, F; Ghazikhanian, V; Ghosh, P; Gonzalez, J E; Grachov, O; Grebenyuk, O; Gronstal, S; Grosnick, D; Guertin, S M; Gupta, A; Gutierrez, T D; Hallman, T J; Hamed, A; Hardtke, D; Harris, J W; Heinz, M; Henry, T W; Heppelmann, S; Herston, T; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horsley, M; Huang, H Z; Huang, S L; Hughes, E; Humanic, T J; Igo, G; Ishihara, A; Jacobs, P; Jacobs, W W; Janik, M; Jiang, H; Johnson, I; Jones, P G; Judd, E G; Kabana, S; Kaplan, M; Keane, D; Khodyrev, V Yu; Kiryluk, J; Kisiel, A; Klay, J; Klein, S R; Klyachko, A; Koetke, D D; Kollegger, T; Kopytine, M; Kotchenda, L; Kovalenko, A D; Kramer, M; Kravtsov, P; Kravtsov, V I; Krueger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kunde, G J; Kunz, C L; Kutuev, R Kh; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; Lasiuk, B; Laue, F; Lauret, J; Lebedev, A; Lednický, R; Levine, M J; Li, C; Li, Q; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, L; Liu, Z; Liu, Q J; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; Lopez-Noriega, M; Love, W A; Ludlam, T; Lynn, D; Ma, J; Ma, Y G; Magestro, D; Mahajan, S; Mangotra, L K; Mahapatra, D P; Majka, R; Manweiler, R; Margetis, S; Markert, C; Martin, L; Marx, J; Matis, H S; Matulenko, Yu A; McClain, C J; McShane, T S; Meissner, F; Melnick, Yu; Meschanin, A; Miller, M L; Milosevich, Z; Minaev, N G; Mironov, C; Mischke, A; Mishra, D; Mitchell, J; Mohanty, B; Molnar, L; Moore, C F; Mora-Corral, M J; Morozov, D A; Morozov, V; de Moura, M M; Munhoz, M G; Nandi, B K; Nayak, S K; Nayak, T K; Nelson, J M; Netrakanti, P K; Nikitin, V A; Nogach, L V; Norman, B; Nurushev, S B; Odyniec, G; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Paic, G; Pal, S K; Panebratsev, Y; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Peitzmann, T; Perevoztchikov, V; Perkins, C; Peryt, W; Petrov, V A; Phatak, S C; Picha, R; Planinic, M; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M; Potrebenikova, E; Potukuchi, B V K S; Prindle, D; Pruneau, C; Putschke, J; Rai, G; Rakness, G; Raniwala, R; Raniwala, S; Ravel, O; Ray, R L; Razin, S V; Reichhold, D; Reid, J G; Renault, G; Retiere, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Ruan, L J; Sahoo, R; Sakrejda, I; Salur, S; Sandweiss, J; Savin, I; Schambach, J; Scharenberg, R P; Schmitz, N; Schroeder, L S; Schweda, K; Seger, J; Seyboth, P; Shahaliev, E; Shao, M; Shao, W; Sharma, M; Shestermanov, K E; Shimanskii, S S; Singaraju, R N; Simon, F; Skoro, G; Smirnov, N; Snellings, R; Sood, G; Sorensen, P; Sowinski, J; Speltz, J; Spinka, H M; Srivastava, B; Stanislaus, T D S; Stock, R; Stolpovsky, A; Strikhanov, M; Stringfellow, B; Struck, C; Suaide, A A P; Sugarbaker, E; Suire, C; Sumbera, M; Surrow, B; Symons, T J M; Szanto de Toledo, A; Szarwas, P; Tai, A; Takahashi, J; Tang, A H; Thein, D; Thomas, J H; Timoshenko, S; Tokarev, M; Tonjes, M B; Trainor, T A; Trentalange, S; Tribble, R E; Tsai, O; Ullrich, T; Underwood, D G; Van Buren, G; Vandermolen, A M; Varma, R; Vasilevski, I; Vasiliev, A N; Vernet, R; Vigdor, S E; Viyogi, Y P; Voloshin, S A; Vznuzdaev, M; Waggoner, W; Wang, F; Wang, G; Wang, G; Wang, X L; Wang, Y; Wang, Z M; Ward, H; Watson, J W; Webb, J C; Wells, R; Westfall, G D; Whitten, C; Wieman, H; Willson, R; Wissink, S W; Witt, R; Wood, J; Wu, J; Xu, N; Xu, Z; Xu, Z Z; Yamamoto, E; Yepes, P; Yurevich, V I; Yuting, B; Zanevski, Y V; Zhang, H; Zhang, W M; Zhang, Z P; Zhaomin, Z P; Zizong, Z P; Zołnierczuk, P A; Zoulkarneev, R; Zoulkarneeva, J; Zubarev, A N

    2005-10-07

    Charged hadrons in [EQUATION: SEE TEXT] associated with particles of [EQUATION: SEE TEXT] are reconstructed in pp and Au+Au collisions at sqrt[sNN]=200 GeV. The associated multiplicity and p magnitude sum are found to increase from pp to central Au+Au collisions. The associated p distributions, while similar in shape on the nearside, are significantly softened on the awayside in central Au+Au relative to pp and not much harder than that of inclusive hadrons. The results, consistent with jet quenching, suggest that the awayside fragments approach equilibration with the medium traversed.

  7. Reconstruction of K*+/-(892) in Au +Au Collisions at √sNN = 200 GeV

    NASA Astrophysics Data System (ADS)

    Zheng, He; STAR Collaboration

    2016-09-01

    The Relativistic Heavy Ion Collider (RHIC) produces a hot, dense and deconfined Quantum ChromoDynamics (QCD) medium, called the quark-gluon plasma (QGP), with Au +Au collisions at √sNN = 200 GeV. The K*+/-(892) resonance is a short-lived particle with a lifetime shorter than the expected lifetime of the QGP. The K* production may provide an effective tool to probe the QGP properties, such as strangeness enhancement. Experimentally, K*+/- analysis is difficult and less studied previously because of large combinatorial background. In recent years, improvements in data sample statistics and particle identification capability promise better K*+/- measurements. In this presentation, we report the reconstruction of K*+/- resonance via the hadronic decay channel K*+/- (892) ->KS0π+/- as a function of transverse momentum (pT) up to 5 GeV/c for various collision centrality classes. The data are Au +Au collisions at √sNN = 200 GeV collected in the year 2011 run from the STAR experiment. Physics implications of our measurements will also be discussed. For the STAR collaboration.

  8. Plasmonic behaviour of sputtered Au nanoisland arrays

    NASA Astrophysics Data System (ADS)

    Tvarožek, V.; Szabó, O.; Novotný, I.; Kováčová, S.; Škriniarová, J.; Šutta, P.

    2017-02-01

    The specificity of the formation of Au sputtered nanoisland arrays (NIA) on a glass substrate or on a ZnO thin film doped by Ga is demonstrated. Statistical analysis of morphology images (SEM, AFM) exhibited the Log-normal distribution of the size (area) of nanoislands-their modus AM varied from 8 to 328 nm2 depending on the sputtering power density, which determined the nominal thicknesses in the range of 2-8 nm. Preferential polycrystalline texture (111) of Au NIA increased with the power density and after annealing. Transverse localised surface plasmonic resonance (LSPR; evaluated by transmission UV-vis spectroscopy) showed the red shift of the extinction peaks (Δl ≤ 100 nm) with an increase of the nominal thickness, and the blue shift (Δλ ≤ -65 nm) after annealing of Au NIA. The plasmonic behaviour of Au NIA was described by modification of a size-scaling universal model using the nominal thin film thickness as a technological scaling parameter. Sputtering of a Ti intermediate adhesive ultrathin film between the glass substrate and gold improves the adhesion of Au nanoislands as well as supporting the formation of more defined Au NIA structures of smaller dimensions.

  9. Gold surfaces and nanoparticles are protected by Au(0)–thiyl species and are destroyed when Au(I)–thiolates form

    PubMed Central

    Reimers, Jeffrey R.; Ford, Michael J.; Halder, Arnab; Ulstrup, Jens; Hush, Noel S.

    2016-01-01

    The synthetic chemistry and spectroscopy of sulfur-protected gold surfaces and nanoparticles is analyzed, indicating that the electronic structure of the interface is Au(0)–thiyl, with Au(I)–thiolates identified as high-energy excited surface states. Density-functional theory indicates that it is the noble character of gold and nanoparticle surfaces that destabilizes Au(I)–thiolates. Bonding results from large van der Waals forces, influenced by covalent bonding induced through s–d hybridization and charge polarization effects that perturbatively mix in some Au(I)–thiolate character. A simple method for quantifying these contributions is presented, revealing that a driving force for nanoparticle growth is nobleization, minimizing Au(I)–thiolate involvement. Predictions that Brust–Schiffrin reactions involve thiolate anion intermediates are verified spectroscopically, establishing a key feature needed to understand nanoparticle growth. Mixing of preprepared Au(I) and thiolate reactants always produces Au(I)–thiolate thin films or compounds rather than monolayers. Smooth links to O, Se, Te, C, and N linker chemistry are established. PMID:26929334

  10. Au 2PbP 2, Au 2TlP 2, and Au 2HgP 2: Ternary Gold Polyphosphides with Lead, Thallium, and Mercury in the Oxidation State Zero

    NASA Astrophysics Data System (ADS)

    Eschen, Marcus; Jeitschko, Wolfgang

    2002-05-01

    The polyphosphide Au2PbP2 was prepared by reaction of the elemental components using liquid lead as a reaction medium. Well-developed crystals were obtained after dissolving the matrix in hydrochloric acid. Their crystal structure was determined from four-circle X-ray diffractometer data: Cmcm, a=323.6(1) pm, b=1137.1(2) pm, c=1121.8(1) pm, Z=4, R=0.023 for 478 structure factors and 20 variable parameters. The structure contains zigzag chains of phosphorus atoms with a typical single-bond distance of 219.4(2) pm. The two different kinds of gold atoms are both in linear phosphorus coordination with typical single-bond distances of 232.6(2) and 234.2(2) pm, and the lead atoms have only metal neighbors (7 Au and 2 Pb). Accordingly, chemical bonding of the compound may be expressed by the formula (Au+1)2Pb±0(P-1)2. The corresponding thallium and mercury polyphosphides Au2TlP2 (a=324.1(1) pm, b=1136.1(1) pm, c=1122.1(1) pm) and Au2HgP2 (a=322.1(1) pm, b=1131.4(2) pm, c=1122.6(1) pm) were found to be almost isotypic with Au2PbP2. Their crystal structures were refined from single-crystal X-ray data to R=0.036 (682 F values, 25 variables) and R=0.026 (539 F values, 35 variables), respectively. The structure of these compounds may also be described as consisting of a three-dimensional network of condensed 8- and 10-membered Au2P6 and Au4P6 rings forming parallel channels, which are filled by the lead, thallium, and mercury atoms. The lead atoms are well localized in these channels, while the thallium and even more the mercury atoms occupy additional positions within these channels. Freshly prepared samples of Au2HgP2 show reproducibly slightly different axial ratios and larger cell volumes (ΔV=0.5%) than those after exposure of the samples to air for several days.

  11. Fabrication of Au25 (SG)18 -ZIF-8 Nanocomposites: A Facile Strategy to Position Au25 (SG)18 Nanoclusters Inside and Outside ZIF-8.

    PubMed

    Luo, Yucheng; Fan, Shiyan; Yu, Wenqian; Wu, Zili; Cullen, David A; Liang, Chaolun; Shi, Jianying; Su, Chengyong

    2018-02-01

    Multifunctional composite materials are currently highly desired for sustainable energy applications. A general strategy to integrate atomically precise Au 25 (SG) 18 with ZIF-8 (Zn(MeIm) 2 , MeIm = 2-methylimidazole), is developed via the typical Zn-carboxylate type of linkage. Au 25 (SG) 18 are uniformly encapsulated into a ZIF-8 framework (Au 25 (SG) 18 @ZIF-8) by coordination-assisted self-assembly. In contrast, Au 25 (SG) 18 integrated by simple impregnation is oriented along the outer surface of ZIF-8 (Au 25 (SG) 18 /ZIF-8). The porous structure and thermal stability of these nanocomposites are characterized by N 2 adsorption-desorption isothermal analysis and thermal gravimetric analysis. The distribution of Au 25 (SG) 18 in the two nanocomposites is confirmed by electron microscopy, and the accessibility of Au 25 (SG) 18 is evaluated by the 4-nitrophenol reduction reaction. The as-prepared nanocomposites retain the high porosity and thermal stability of the ZIF-8 matrix, while also exhibiting the desired catalytic and optical properties derived from the integrated Au 25 (SG) 18 nanoclusters (NCs). Au 25 (SG) 18 @ZIF-8 with isolated Au 25 sites is a promising heterogenous catalyst with size selectivity imparted by the ZIF-8 matrix. The structural distinction between Au 25 (SG) 18 @ZIF-8 and Au 25 (SG) 18 /ZIF-8 determines their different emission features, and provides a new strategy to adjust the optical behavior of Au 25 (SG) 18 for applications in bioimaging and biotherapy. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Imaging of a parapharyngeal hemangiopericytoma. Radioimmunoscintigraphy (SPECT) with indium-111-labeled anti-CEA antibody, and comparison to digital subtraction angiography, computed tomography, and immunohistochemistry

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kairemo, K.J.; Hopsu, E.V.; Melartin, E.J.

    1991-01-01

    A 27-year-old male patient with a parapharyngeal hemangiopericytoma was investigated radiologically with orthopantomography, computed tomography, and digital subtraction angiography before the operation. Because a malignancy was suspected, the patient was imaged with gamma camera using radiolabeled monoclonal anticarcinoembryonal antigen antibody including single photon emission computed tomography. The radioantibody accumulated strongly into the neoplasm. Tumor to background ratio was 2.2. Samples of the excised tumor were stained immunohistochemically for desmin, vimentin, muscle actin, cytokeratin, CEA (carcinoembryonic antigen), and factor VIII. They showed that the antibody uptake was of unspecific nature and not due to CEA expression in the tumor.

  13. Positron annihilation study of cavities in black Au films

    NASA Astrophysics Data System (ADS)

    Melikhova, O.; Čížek, J.; Hruška, P.; Vlček, M.; Procházka, I.; Anwand, W.; Novotný, M.; Bulíř, J.

    2017-01-01

    Defects in a black Au film were studied using variable energy positron annihilation spectroscopy. Black Au films exhibit porous morphology similar to cauliflower. This type of structure enhances the optical absorption due to a multiple reflections in the micro-cavities. A nanostructured black Au film was compared with conventional smooth Au films with high reflectivity. The black Au film exhibited a remarkably enhanced S-parameter in sub-surface region. This is caused by a narrow para-Positronium contribution to the annihilation peak.

  14. Study on the failure temperature of Ti/Pt/Au and Pt5Si2-Ti/Pt/Au metallization systems

    NASA Astrophysics Data System (ADS)

    Zhang, Jie; Han, Jianqiang; Yin, Yijun; Dong, Lizhen; Niu, Wenju

    2017-09-01

    The Ti/Pt/Au metallization system has an advantage of resisting KOH or TMAH solution etching. To form a good ohmic contact, the Ti/Pt/Au metallization system must be alloyed at 400 °C. However, the process temperatures of typical MEMS packaging technologies, such as anodic bonding, glass solder bonding and eutectic bonding, generally exceed 400 °C. It is puzzling if the Ti/Pt/Au system is destroyed during the subsequent packaging process. In the present work, the resistance of doped polysilicon resistors contacted by the Ti/Pt/Au metallization system that have undergone different temperatures and time are measured. The experimental results show that the ohmic contacts will be destroyed if heated to 500 °C. But if a 20 nm Pt film is sputtered on heavily doped polysilicon and alloyed at 700 °C before sputtering Ti/Pt/Au films, the Pt5Si2-Ti/Pt/Au metallization system has a higher service temperature of 500 °C, which exceeds process temperatures of most typical MEMS packaging technologies. Project supported by the National Natural Science Foundation of China (No. 61376114).

  15. Low-mass e+e- mass distributions from 1.23A GeV Au+Au collisions with HADES

    NASA Astrophysics Data System (ADS)

    Galatyuk, Tetyana; Hades Collaboration

    2017-11-01

    We present measurements of low-mass electron pairs for the Au+Au system based on a data sample of 2.6 billion events of the 40% most central collisions. In order to understand the microscopic structure of matter in the region of high baryochemical potential HADES pursues a strategy, which relies on systematic measurements of virtual photons emission in elementary and heavy-ion collisions. As of now, HADES has completed measurements of rare penetrating probes in p+p, n+p, C+C, p+Nb and Ar+KCl collisions. In continuation of a systematic investigation of the emissivity of strongly interacting matter, HADES has recently measured the dielectron emission in Au+Au collisions at 1.23A GeV beam energy. This measurement is part of the beam energy scan and marks lowest point in the excitation function of low-mass thermal dilepton radiation.

  16. Formation, Migration, and Reactivity of Au CO Complexes on Gold Surfaces

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wang, Jun; McEntee, Monica; Tang, Wenjie

    2016-01-12

    Here, we report experimental as well as theoretical evidence that suggests Au CO complex formation upon the exposure of CO to active sites (step edges and threading dislocations) on a Au(111) surface. Room-temperature scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy, transmission infrared spectroscopy, and density functional theory calculations point to Au CO complex formation and migration. Room-temperature STM of the Au(111) surface at CO pressures in the range from 10^ 8 to 10^ 4 Torr (dosage up to 10^6 langmuir) indicates Au atom extraction from dislocation sites of the herringbone reconstruction, mobile Au CO complex formation and diffusion, and Aumore » adatom cluster formation on both elbows and step edges on the Au surface. The formation and mobility of the Au CO complex result from the reduced Au Au bonding at elbows and step edges leading to stronger Au CO bonding and to the formation of a more positively charged CO (CO +) on Au. These studies indicate that the mobile Au CO complex is involved in the Au nanoparticle formation and reactivity, and that the positive charge on CO increases due to the stronger adsorption of CO at Au sites with lower coordination numbers.« less

  17. Electronic Absorption and MCD Spectra for Pd(AuPPh(3))(8)(2+), Pt(AuPPh(3))(8)(2+), and Related Platinum-Centered Gold Cluster Complexes.

    PubMed

    Adrowski, Michael J.; Mason, W. Roy

    1997-03-26

    Electronic absorption and 7.0 T magnetic circular dichroism (MCD) spectra in the UV-vis region, 1.6 to approximately 4.0 &mgr;m(-)(1) (1 &mgr;m(-)(1) = 10(4) cm(-)(1)) are reported for [Pd(AuPPh(3))(8)](NO(3))(2) and [Pt(AuPPh(3))(8)](NO(3))(2) in acetonitrile solutions at room temperature. The MCD spectra are better resolved than the absorption spectra and consist of both A and B terms. The spectra are interpreted in terms of D(4)(d)() skeletal geometry and MO's that are approximated by 5s and 6s orbitals for Pd and Pt/Au atoms, respectively. The lowest energy excited configurations and states are attributed to intraframework (IF) Au(8)(2+) transitions. Evidence is also presented for Pt 5d --> Au 6s transitions in the MCD spectra for Pt(AuPPh(3))(8)(2+). Acetonitrile solution absorption and MCD spectra for the related Pt-centered cluster complexes [Pt(CO)(AuPPh(3))(8)](NO(3))(2), [Pt(AuP(p-tolyl)(3))(8)](NO(3))(2), [Pt(CuCl)(AuPPh(3))(8)](NO(3))(2), [Pt(AgNO(3))(AuPPh(3))(8)](NO(3))(2), [Pt(Hg)(2)(AuPPh(3))(8)](NO(3))(2), [Pt(HgCl)(2)(AuPPh(3))(8)](BF(4))(2), and [Pt(HgNO(3))(2)(AuPPh(3))(8)](BF(4))(2) are also reported and interpreted within the context of the model developed for the M(AuPPh(3))(8)(2+) complexes.

  18. High Activity of Au/K/TiO 2(110) for CO Oxidation: Alkali-Metal-Enhanced Dispersion of Au and Bonding of CO

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rodriguez, Jose A.; Grinter, David C.; Ramirez, Pedro J.

    In this paper, images from scanning tunneling microscopy show high mobility for potassium (K) on an oxidized TiO 2(110) surface. At low coverages, the alkali metal occupies mainly terrace sites of the o-TiO 2(110) system. The results of X-ray photoelectron spectroscopy indicate that K is fully ionized. The electron transferred from K to the titania affects the reactivity of this oxide, favoring the dispersion of Au particles on the terraces of the o-TiO 2(110) surface. When small coverages of K and Au are present on the o-TiO 2(110) system, only a few K–Au pairs are formed and the alkali metalmore » affects Au chemisorption mainly through the oxide interactions. Addition of K to Au/o-TiO 2(110) enhances the reactivity of the system, opening new reaction paths for the adsorption and oxidation of carbon monoxide. CO can undergo disproportionation (2CO → C ads + CO 2,ads) on K/o-TiO 2(110) and Au/K/o-TiO 2(110) surfaces. The Au–KO x interface binds CO much better than plain Au–TiO 2, increasing the surface coverage of CO and facilitating its oxidation. Kinetic tests show that K promotes CO oxidation on Au/TiO 2. Finally, turnover frequencies of 2.1 and 10.8 molecules (Au site) -1 s –1 were calculated for oxidation of CO on Au/o-TiO 2(110) and Au/K/o-TiO 2(110) catalysts, respectively.« less

  19. High Activity of Au/K/TiO 2(110) for CO Oxidation: Alkali-Metal-Enhanced Dispersion of Au and Bonding of CO

    DOE PAGES

    Rodriguez, Jose A.; Grinter, David C.; Ramirez, Pedro J.; ...

    2018-02-14

    In this paper, images from scanning tunneling microscopy show high mobility for potassium (K) on an oxidized TiO 2(110) surface. At low coverages, the alkali metal occupies mainly terrace sites of the o-TiO 2(110) system. The results of X-ray photoelectron spectroscopy indicate that K is fully ionized. The electron transferred from K to the titania affects the reactivity of this oxide, favoring the dispersion of Au particles on the terraces of the o-TiO 2(110) surface. When small coverages of K and Au are present on the o-TiO 2(110) system, only a few K–Au pairs are formed and the alkali metalmore » affects Au chemisorption mainly through the oxide interactions. Addition of K to Au/o-TiO 2(110) enhances the reactivity of the system, opening new reaction paths for the adsorption and oxidation of carbon monoxide. CO can undergo disproportionation (2CO → C ads + CO 2,ads) on K/o-TiO 2(110) and Au/K/o-TiO 2(110) surfaces. The Au–KO x interface binds CO much better than plain Au–TiO 2, increasing the surface coverage of CO and facilitating its oxidation. Kinetic tests show that K promotes CO oxidation on Au/TiO 2. Finally, turnover frequencies of 2.1 and 10.8 molecules (Au site) -1 s –1 were calculated for oxidation of CO on Au/o-TiO 2(110) and Au/K/o-TiO 2(110) catalysts, respectively.« less

  20. Charged particle multiplicity fluctuations in Au + Au collisions at √sNN = 200 GeV

    NASA Astrophysics Data System (ADS)

    Wozniak, Krzysztof; the PHOBOS Collaboration; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Chai, Z.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tang, J. L.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wolfs, F. L. H.; Wosiek, B.; Wuosmaa, A. H.; Wysłouch, B.

    2004-08-01

    This paper presents the first PHOBOS results on charged particle multiplicity fluctuations measured for Au+Au collisions at the highest RHIC energy within a wide pseudorapidity range of |η| < 3. The dependence on collision geometry is removed in the analysis by using the normalized difference between the number of particles in separate η bins. We compare our data to HIJING model predictions.

  1. AuRu/AC as an effective catalyst for hydrogenation reactions

    DOE PAGES

    Villa, Alberto; Chan-Thaw, Carine E.; Campisi, Sebastiano; ...

    2015-03-23

    AuRu bimetallic catalysts have been prepared by sequential deposition of Au on Ru or vice versa obtaining different nanostructures: when Ru has been deposited on Au, a Au core–Ru shell has been observed, whereas the deposition of Au on Ru leads to a bimetallic phase with Ru enrichment on the surface. In the latter case, the unexpected Ru enrichment could be attributed to the weak adhesion of Ru on the carbon support, thus allowing Ru particles to diffuse on Au particles. Both structures result very active in catalysing the liquid phase hydrogenolysis of glycerol and levulinic acid but the activity,more » the selectivity and the stability depend on the structure of the bimetallic nanoparticles. Ru@Au/AC core–shell structure mostly behaved as the monometallic Ru, whereas the presence of bimetallic AuRu phase in Au@Ru/AC provides a great beneficial effect on both activity and stability.« less

  2. AU-FREDI - AUTONOMOUS FREQUENCY DOMAIN IDENTIFICATION

    NASA Technical Reports Server (NTRS)

    Yam, Y.

    1994-01-01

    The Autonomous Frequency Domain Identification program, AU-FREDI, is a system of methods, algorithms and software that was developed for the identification of structural dynamic parameters and system transfer function characterization for control of large space platforms and flexible spacecraft. It was validated in the CALTECH/Jet Propulsion Laboratory's Large Spacecraft Control Laboratory. Due to the unique characteristics of this laboratory environment, and the environment-specific nature of many of the software's routines, AU-FREDI should be considered to be a collection of routines which can be modified and reassembled to suit system identification and control experiments on large flexible structures. The AU-FREDI software was originally designed to command plant excitation and handle subsequent input/output data transfer, and to conduct system identification based on the I/O data. Key features of the AU-FREDI methodology are as follows: 1. AU-FREDI has on-line digital filter design to support on-orbit optimal input design and data composition. 2. Data composition of experimental data in overlapping frequency bands overcomes finite actuator power constraints. 3. Recursive least squares sine-dwell estimation accurately handles digitized sinusoids and low frequency modes. 4. The system also includes automated estimation of model order using a product moment matrix. 5. A sample-data transfer function parametrization supports digital control design. 6. Minimum variance estimation is assured with a curve fitting algorithm with iterative reweighting. 7. Robust root solvers accurately factorize high order polynomials to determine frequency and damping estimates. 8. Output error characterization of model additive uncertainty supports robustness analysis. The research objectives associated with AU-FREDI were particularly useful in focusing the identification methodology for realistic on-orbit testing conditions. Rather than estimating the entire structure, as is

  3. Photon interferometry of Au+Au collisions at the BNL Relativistic Heavy-Ion Collider.

    PubMed

    Bass, Steffen A; Müller, Berndt; Srivastava, Dinesh K

    2004-10-15

    We calculate the two-body correlation function of direct photons produced in central Au+Au collisions at the Relativistic Heavy-Ion Collider. Our calculation includes contributions from the early preequilibrium phase in which photons are produced via hard parton scatterings as well as radiation of photons from a thermalized quark-gluon plasma and the subsequent expanding hadron gas. We find that high energy photon interferometry provides a faithful probe of the details of the space-time evolution and of the early reaction stages of the system.

  4. Novel condensation of Au-centered trigonal prisms in rare-earth-metal-rich tellurides: Er7Au2Te2 and Lu7Au2Te2.

    PubMed

    Gupta, Shalabh; Corbett, John D

    2010-07-14

    A new monoclinic structure occurs for Er(7)Au(2)Te(2) according to X-ray diffraction analysis of single crystals grown at 1200 degrees C: C2/m, Z = 4, a = 17.8310(9) A, b = 3.9819(5) A, c = 16.9089(9) A, beta = 104.361(4) degrees. The isostructural Lu(7)Au(2)Te(2) also exists according to X-ray powder pattern means, a = 17.536(4) A, b = 3.9719(4) A, c = 16.695(2) A, beta = 104.33(1) degrees. The structure contains zigzag chains of condensed, Au-centered tricapped trigonal prisms (TCTP) of Er along c that also share basal faces along b to generate puckered sheets. Further bi-face-capping Er atoms between these generate the three dimensional network along a, with tellurium in cavities outlined by augmented trigonal prismatic Er polyhedra. Bonding analysis via LMTO-DFT methods reveal very significant Er-Au bonding interactions, as quantified by their energy-weighted Hamilton overlap populations (-ICOHP), approximately 49% of the total for all interactions. These and similar Er-Te contributions sharply contrast with the small Er-Er population, only approximately 14% of the total in spite of the high proportion of Er-Er contacts. The strong polar bonding of Er to the electronegative Au and Te leaves Er relatively oxidized, with many of its 5d states falling above the Fermi level and empty. The contradiction with customary representations of structures that highlight rare-earth metal clusters is manifest. The large Er-Au Hamilton overlap population is in accord with the strong bonding between early and late transition metals first noted by Brewer in 1973. The relationship of this structure to the more distorted orthorhombic (Imm2) structure type of neighboring Dy(7)Ir(2)Te(2) is considered.

  5. Electron transfer catalysis with monolayer protected Au25 clusters

    NASA Astrophysics Data System (ADS)

    Antonello, Sabrina; Hesari, Mahdi; Polo, Federico; Maran, Flavio

    2012-08-01

    Au25L18 (L = S(CH2)2Ph) clusters were prepared and characterized. The resulting monodisperse clusters were reacted with bis(pentafluorobenzoyl) peroxide in dichloromethane to form Au25L18+ quantitatively. The kinetics and thermodynamics of the corresponding electron transfer (ET) reactions were characterized via electrochemistry and thermochemical calculations. Au25L18+ was used in homogeneous redox catalysis experiments with a series of sym-substituted benzoyl peroxides, including the above peroxide, bis(para-cyanobenzoyl) peroxide, dibenzoyl peroxide, and bis(para-methoxybenzoyl) peroxide. Peroxide dissociative ET was catalyzed using both the Au25L18/Au25L18- and the Au25L18+/Au25L18 redox couples as redox mediators. Simulation of the CV curves led to determination of the ET rate constant (kET) values for concerted dissociative ET to the peroxides. The ET free energy ΔG° could be estimated for all donor-acceptor combinations, leading to observation of a nice activation-driving force (log kETvs. ΔG°) relationship. Comparison with the kET obtained using a ferrocene-type donor with a formal potential similar to that of Au25L18/Au25L18- showed that the presence of the capping monolayer affects the ET rate rather significantly, which is attributed to the intrinsic nonadiabaticity of peroxide acceptors.Au25L18 (L = S(CH2)2Ph) clusters were prepared and characterized. The resulting monodisperse clusters were reacted with bis(pentafluorobenzoyl) peroxide in dichloromethane to form Au25L18+ quantitatively. The kinetics and thermodynamics of the corresponding electron transfer (ET) reactions were characterized via electrochemistry and thermochemical calculations. Au25L18+ was used in homogeneous redox catalysis experiments with a series of sym-substituted benzoyl peroxides, including the above peroxide, bis(para-cyanobenzoyl) peroxide, dibenzoyl peroxide, and bis(para-methoxybenzoyl) peroxide. Peroxide dissociative ET was catalyzed using both the Au25L18/Au25L18- and

  6. Multi-arm Cost-Effectiveness Analysis (CEA) comparing different durations of adjuvant trastuzumab in early breast cancer, from the English NHS payer perspective

    PubMed Central

    Hunter, Rachael M.; Shemilt, Ian; Serra-Sastre, Victoria

    2017-01-01

    Background Trastuzumab improves survival in HER2+ breast cancer patients, with some evidence of adverse cardiac side effects. Current recommendations are to give adjuvant trastuzumab for one year or until recurrence, although trastuzumab treatment for only 9 or 10 weeks has shown similar survival rates to 12-month treatment. We present here a multi-arm joint analysis examining the relative cost-effectiveness of different durations of adjuvant trastuzumab. Methods and findings Network meta-analysis (NMA) was used to examine which trials’ data to include in the cost-effectiveness analysis (CEA). A network using FinHer (9 weeks vs. zero) and BCIRG006 (12 months vs. zero) trials offered the only jointly randomisable network so these trials were used in the CEA. The 3-arm CEA compared costs and quality-adjusted life-years (QALYs) associated with zero, 9-week and 12-month adjuvant trastuzumab durations in early breast cancer, using a decision tree followed by a Markov model that extrapolated the results to a lifetime time horizon. Pairwise incremental cost-effectiveness ratios (ICERs) were also calculated for each pair of regimens and used in budget impact analysis, and the Bucher method was used to check face validity of the findings. Addition of the PHARE trial (6 months vs. 12 months) to the network, in order to create a 4-arm CEA including the 6-month regimen, was not possible as late randomisation in this trial resulted in recruitment of a different patient population as evidenced by the NMA findings. The CEA results suggest that 9 weeks’ trastuzumab is cost-saving and leads to more QALYs than 12 months’, i.e. the former dominates the latter. The cost-effectiveness acceptability frontier (CEAF) favours zero trastuzumab at willingness-to-pay levels below £2,500/QALY and treatment for 9 weeks above this threshold. The combination of the NMA and Bucher investigations suggests that the 9-week duration is as efficacious as the 12-month duration for distant

  7. Multi-arm Cost-Effectiveness Analysis (CEA) comparing different durations of adjuvant trastuzumab in early breast cancer, from the English NHS payer perspective.

    PubMed

    Clarke, Caroline S; Hunter, Rachael M; Shemilt, Ian; Serra-Sastre, Victoria

    2017-01-01

    Trastuzumab improves survival in HER2+ breast cancer patients, with some evidence of adverse cardiac side effects. Current recommendations are to give adjuvant trastuzumab for one year or until recurrence, although trastuzumab treatment for only 9 or 10 weeks has shown similar survival rates to 12-month treatment. We present here a multi-arm joint analysis examining the relative cost-effectiveness of different durations of adjuvant trastuzumab. Network meta-analysis (NMA) was used to examine which trials' data to include in the cost-effectiveness analysis (CEA). A network using FinHer (9 weeks vs. zero) and BCIRG006 (12 months vs. zero) trials offered the only jointly randomisable network so these trials were used in the CEA. The 3-arm CEA compared costs and quality-adjusted life-years (QALYs) associated with zero, 9-week and 12-month adjuvant trastuzumab durations in early breast cancer, using a decision tree followed by a Markov model that extrapolated the results to a lifetime time horizon. Pairwise incremental cost-effectiveness ratios (ICERs) were also calculated for each pair of regimens and used in budget impact analysis, and the Bucher method was used to check face validity of the findings. Addition of the PHARE trial (6 months vs. 12 months) to the network, in order to create a 4-arm CEA including the 6-month regimen, was not possible as late randomisation in this trial resulted in recruitment of a different patient population as evidenced by the NMA findings. The CEA results suggest that 9 weeks' trastuzumab is cost-saving and leads to more QALYs than 12 months', i.e. the former dominates the latter. The cost-effectiveness acceptability frontier (CEAF) favours zero trastuzumab at willingness-to-pay levels below £2,500/QALY and treatment for 9 weeks above this threshold. The combination of the NMA and Bucher investigations suggests that the 9-week duration is as efficacious as the 12-month duration for distant-disease-free survival and overall survival

  8. CEA to peritoneal carcinomatosis index (PCI) ratio is prognostic in patients with colorectal cancer peritoneal carcinomatosis undergoing cytoreduction surgery and intraperitoneal chemotherapy: A retrospective cohort study.

    PubMed

    Kozman, Mathew A; Fisher, Oliver M; Rebolledo, Bree-Anne J; Parikh, Roneil; Valle, Sarah J; Arrowaili, Arief; Alzahrani, Nayef; Liauw, Winston; Morris, David L

    2018-03-01

    Serum tumor markers are prognostic in patients with colorectal cancer peritoneal carcinomatosis (CRPC) undergoing cytoreductive surgery (CRS) and intraperitoneal chemotherapy (IPC). Assessment of the ratio of tumor marker to volume, as depicted by peritoneal carcinomatosis index (PCI), and how this may affect overall (OS) and recurrence free survival (RFS) has not been reported. Survival effect of this ratio was analyzed in patients with CRPC managed from 1996 to 2016 with CRS and IPC. Of 260 patients included, those with low CEA/PCI ratio (<2.3) had longer median OS (56 vs 24 months, P = 0.001) and RFS (13 vs 9 months, P = 0.02). The prognostic impact of CEA/PCI ratio was most pronounced in patients with PCI ≤ 10 (OS of 72 vs 30 months, P < 0.001; RFS of 21 vs 10 months, P = 0.002). In multivariable analysis, elevated CEA/PCI ratio was independently associated with poorer OS (adjusted HR 1.85, 95%CI 1.11-3.10, P = 0.02) and RFS (adjusted HR 1.58, 95%CI 1.04-2.41, P = 0.03). CEA/PCI ratio is an independent prognostic factor for OS and RFS in CRPC. This novel approach allows both tumor activity and volume to be accounted for in one index, thus potentially providing a more accurate indication of tumor biological behavior. © 2017 Wiley Periodicals, Inc.

  9. Transverse-momentum and collision-energy dependence of high-pT hadron suppression in Au+Au collisions at ultrarelativistic energies.

    PubMed

    Adams, J; Adler, C; Aggarwal, M M; Ahammed, Z; Amonett, J; Anderson, B D; Anderson, M; Arkhipkin, D; Averichev, G S; Badyal, S K; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellwied, R; Berger, J; Bezverkhny, B I; Bhardwaj, S; Bhaskar, P; Bhati, A K; Bichsel, H; Billmeier, A; Bland, L C; Blyth, C O; Bonner, B E; Botje, M; Boucham, A; Brandin, A; Bravar, A; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca Sánchez, M; Carroll, J; Castillo, J; Castro, M; Cebra, D; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, Y; Chernenko, S P; Cherney, M; Chikanian, A; Choi, B; Christie, W; Coffin, J P; Cormier, T M; Cramer, J G; Crawford, H J; Das, D; Das, S; Derevschikov, A A; Didenko, L; Dietel, T; Dong, X; Draper, J E; Drees, K A; Du, F; Dubey, A K; Dunin, V B; Dunlop, J C; Dutta Majumdar, M R; Eckardt, V; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Fachini, P; Faine, V; Faivre, J; Fatemi, R; Filimonov, K; Filip, P; Finch, E; Fisyak, Y; Flierl, D; Foley, K J; Fu, J; Gagliardi, C A; Ganti, M S; Gagunashvili, N; Gans, J; Gaudichet, L; Germain, M; Geurts, F; Ghazikhanian, V; Ghosh, P; Gonzalez, J E; Grachov, O; Grigoriev, V; Gronstal, S; Grosnick, D; Guedon, M; Guertin, S M; Gupta, A; Gushin, E; Gutierrez, T D; Hallman, T J; Hardtke, D; Harris, J W; Heinz, M; Henry, T W; Heppelmann, S; Herston, T; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horsley, M; Huang, H Z; Huang, S L; Humanic, T J; Igo, G; Ishihara, A; Jacobs, P; Jacobs, W W; Janik, M; Johnson, I; Jones, P G; Judd, E G; Kabana, S; Kaneta, M; Kaplan, M; Keane, D; Kiryluk, J; Kisiel, A; Klay, J; Klein, S R; Klyachko, A; Kollegger, T; Konstantinov, A S; Kopytine, M; Kotchenda, L; Kovalenko, A D; Kramer, M; Kravtsov, P; Krueger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kunde, G J; Kunz, C L; Kutuev, R Kh; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; Lansdell, C P; Lasiuk, B; Laue, F; Lauret, J; Lebedev, A; Lednický, R; Leontiev, V M; LeVine, M J; Li, C; Li, Q; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, L; Liu, Z; Liu, Q J; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; Lopez-Noriega, M; Love, W A; Ludlam, T; Lynn, D; Ma, J; Ma, Y G; Magestro, D; Mahajan, S; Mangotra, L K; Mahapatra, D P; Majka, R; Manweiler, R; Margetis, S; Markert, C; Martin, L; Marx, J; Matis, H S; Matulenko, Yu A; McShane, T S; Meissner, F; Melnick, Yu; Meschanin, A; Messer, M; Miller, M L; Milosevich, Z; Minaev, N G; Mironov, C; Mishra, D; Mitchell, J; Mohanty, B; Molnar, L; Moore, C F; Mora-Corral, M J; Morozov, V; de Moura, M M; Munhoz, M G; Nandi, B K; Nayak, S K; Nayak, T K; Nelson, J M; Nevski, P; Nikitin, V A; Nogach, L V; Norman, B; Nurushev, S B; Odyniec, G; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Paic, G; Pandey, S U; Pal, S K; Panebratsev, Y; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Perevoztchikov, V; Peryt, W; Petrov, V A; Phatak, S C; Picha, R; Planinic, M; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M; Potrebenikova, E; Potukuchi, B V K S; Prindle, D; Pruneau, C; Putschke, J; Rai, G; Rakness, G; Raniwala, R; Raniwala, S; Ravel, O; Ray, R L; Razin, S V; Reichhold, D; Reid, J G; Renault, G; Retiere, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Ruan, L J; Rykov, V; Sahoo, R; Sakrejda, I; Salur, S; Sandweiss, J; Savin, I; Schambach, J; Scharenberg, R P; Schmitz, N; Schroeder, L S; Schweda, K; Seger, J; Seliverstov, D; Seyboth, P; Shahaliev, E; Shao, M; Sharma, M; Shestermanov, K E; Shimanskii, S S; Singaraju, R N; Simon, F; Skoro, G; Smirnov, N; Snellings, R; Sood, G; Sorensen, P; Sowinski, J; Spinka, H M; Srivastava, B; Stanislaus, S; Stock, R; Stolpovsky, A; Strikhanov, M; Stringfellow, B; Struck, C; Suaide, A A P; Sugarbaker, E; Suire, C; Sumbera, M; Surrow, B; Symons, T J M; Szanto de Toledo, A; Szarwas, P; Tai, A; Takahashi, J; Tang, A H; Thein, D; Thomas, J H; Tikhomirov, V; Tokarev, M; Tonjes, M B; Trainor, T A; Trentalange, S; Tribble, R E; Trivedi, M D; Trofimov, V; Tsai, O; Ullrich, T; Underwood, D G; Van Buren, G; VanderMolen, A M; Vasiliev, A N; Vasiliev, M; Vigdor, S E; Viyogi, Y P; Voloshin, S A; Waggoner, W; Wang, F; Wang, G; Wang, X L; Wang, Z M; Ward, H; Watson, J W; Wells, R; Westfall, G D; Whitten, C; Wieman, H; Willson, R; Wissink, S W; Witt, R; Wood, J; Wu, J; Xu, N; Xu, Z; Xu, Z Z; Yakutin, A E; Yamamoto, E; Yang, J; Yepes, P; Yurevich, V I; Zanevski, Y V; Zborovský, I; Zhang, H; Zhang, H Y; Zhang, W M; Zhang, Z P; Zołnierczuk, P A; Zoulkarneev, R; Zoulkarneeva, J; Zubarev, A N

    2003-10-24

    We report high statistics measurements of inclusive charged hadron production in Au+Au and p+p collisions at sqrt[s(NN)]=200 GeV. A large, approximately constant hadron suppression is observed in central Au+Au collisions for 5

  10. Fabrication of Au 25(SG) 18–ZIF-8 Nanocomposites: A Facile Strategy to Position Au 25(SG) 18 Nanoclusters Inside and Outside ZIF-8

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Luo, Yucheng; Fan, Shiyan; Yu, Wenqian

    Multifunctional composite materials are currently highly desired for sustainable energy applications. A general strategy to integrate atomically precise Au 25(SG) 18 with ZIF-8 (Zn(MeIm) 2, MeIm = 2-methylimidazole), is developed in this paper via the typical Zn-carboxylate type of linkage. Au 25(SG) 18 are uniformly encapsulated into a ZIF-8 framework (Au 25(SG) 18@ZIF-8) by coordination-assisted self-assembly. In contrast, Au 25(SG) 18 integrated by simple impregnation is oriented along the outer surface of ZIF-8 (Au 25(SG) 18/ZIF-8). The porous structure and thermal stability of these nanocomposites are characterized by N 2 adsorption–desorption isothermal analysis and thermal gravimetric analysis. The distribution ofmore » Au 25(SG) 18 in the two nanocomposites is confirmed by electron microscopy, and the accessibility of Au 25(SG) 18 is evaluated by the 4-nitrophenol reduction reaction. The as-prepared nanocomposites retain the high porosity and thermal stability of the ZIF-8 matrix, while also exhibiting the desired catalytic and optical properties derived from the integrated Au 25(SG) 18 nanoclusters (NCs). Au 25(SG) 18@ZIF-8 with isolated Au 25 sites is a promising heterogenous catalyst with size selectivity imparted by the ZIF-8 matrix. Finally, the structural distinction between Au 25(SG) 18@ZIF-8 and Au 25(SG) 18/ZIF-8 determines their different emission features, and provides a new strategy to adjust the optical behavior of Au 25(SG) 18 for applications in bioimaging and biotherapy.« less

  11. Fabrication of Au 25(SG) 18–ZIF-8 Nanocomposites: A Facile Strategy to Position Au 25(SG) 18 Nanoclusters Inside and Outside ZIF-8

    DOE PAGES

    Luo, Yucheng; Fan, Shiyan; Yu, Wenqian; ...

    2017-12-22

    Multifunctional composite materials are currently highly desired for sustainable energy applications. A general strategy to integrate atomically precise Au 25(SG) 18 with ZIF-8 (Zn(MeIm) 2, MeIm = 2-methylimidazole), is developed in this paper via the typical Zn-carboxylate type of linkage. Au 25(SG) 18 are uniformly encapsulated into a ZIF-8 framework (Au 25(SG) 18@ZIF-8) by coordination-assisted self-assembly. In contrast, Au 25(SG) 18 integrated by simple impregnation is oriented along the outer surface of ZIF-8 (Au 25(SG) 18/ZIF-8). The porous structure and thermal stability of these nanocomposites are characterized by N 2 adsorption–desorption isothermal analysis and thermal gravimetric analysis. The distribution ofmore » Au 25(SG) 18 in the two nanocomposites is confirmed by electron microscopy, and the accessibility of Au 25(SG) 18 is evaluated by the 4-nitrophenol reduction reaction. The as-prepared nanocomposites retain the high porosity and thermal stability of the ZIF-8 matrix, while also exhibiting the desired catalytic and optical properties derived from the integrated Au 25(SG) 18 nanoclusters (NCs). Au 25(SG) 18@ZIF-8 with isolated Au 25 sites is a promising heterogenous catalyst with size selectivity imparted by the ZIF-8 matrix. Finally, the structural distinction between Au 25(SG) 18@ZIF-8 and Au 25(SG) 18/ZIF-8 determines their different emission features, and provides a new strategy to adjust the optical behavior of Au 25(SG) 18 for applications in bioimaging and biotherapy.« less

  12. Corrosion behavior and microstructures of experimental Ti-Au alloys.

    PubMed

    Takahashi, Masatoshi; Kikuchi, Masafumi; Takada, Yukyo; Okuno, Osamu; Okabe, Toru

    2004-06-01

    Anodic polarization was performed in 0.9% NaCl and 1% lactic acid solutions to characterize the relationship between the corrosion behavior and microstructures of cast Ti-Au (5-40%) alloys. An abrupt increase in the current density occurred at approximately 0.6 V vs. SCE for the 30% and 40% Au alloys in the 0.9% NaCl solution. The microstructures after corrosion testing indicated that this breakdown may have been caused by the preferential dissolution of the Ti3Au. However, the potential for preferential dissolution was higher than the breakdown potential of stainless steel or Co-Cr alloy, which meant that the corrosion resistance of the Ti-Au alloys was superior. In 1% lactic acid solution, the corrosion resistance of the Ti-Au alloys was excellent, with no breakdown at any composition. In the present test solutions, the Ti-Au alloys up to 20% Au had good corrosion resistance comparable to that for pure titanium.

  13. Measurement of D 0 Azimuthal Anisotropy at Midrapidity in Au + Au Collisions at s N N = 200 GeV

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.

    In this paper, we report the first measurement of the elliptic anisotropy (v2) of the charm meson D 0 at midrapidity (|y| < 1) in Au + Au collisions atmore » $$\\sqrt{s}$$$_ {NN}$$ = 200 GeV. The measurement was conducted by the STAR experiment at RHIC utilizing a new high-resolution silicon tracker. The measured D 0 v 2 in 0%–80% centrality Au + Au collisions can be described by a viscous hydrodynamic calculation for a transverse momentum (p T) of less than 4 GeV/c . The D 0 v 2 as a function of transverse kinetic energy (m T - m 0 , where m T = $$\\sqrt{p}$$$2\\atop{T}$$ + m$$2\\atop{0}$$) is consistent with that of light mesons in 10%–40% centrality Au + Au collisions. These results suggest that charm quarks have achieved local thermal equilibrium with the medium created in such collisions. In conclusion, several theoretical models, with the temperature-dependent, dimensionless charm spatial diffusion coefficient (2πTD s) in the range of ~2–12 , are able to simultaneously reproduce our D 0 v 2 result and our previously published results for the D 0 nuclear modification factor.« less

  14. Measurement of D 0 Azimuthal Anisotropy at Midrapidity in Au + Au Collisions at s N N = 200 GeV

    DOE PAGES

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; ...

    2017-05-26

    In this paper, we report the first measurement of the elliptic anisotropy (v2) of the charm meson D 0 at midrapidity (|y| < 1) in Au + Au collisions atmore » $$\\sqrt{s}$$$_ {NN}$$ = 200 GeV. The measurement was conducted by the STAR experiment at RHIC utilizing a new high-resolution silicon tracker. The measured D 0 v 2 in 0%–80% centrality Au + Au collisions can be described by a viscous hydrodynamic calculation for a transverse momentum (p T) of less than 4 GeV/c . The D 0 v 2 as a function of transverse kinetic energy (m T - m 0 , where m T = $$\\sqrt{p}$$$2\\atop{T}$$ + m$$2\\atop{0}$$) is consistent with that of light mesons in 10%–40% centrality Au + Au collisions. These results suggest that charm quarks have achieved local thermal equilibrium with the medium created in such collisions. In conclusion, several theoretical models, with the temperature-dependent, dimensionless charm spatial diffusion coefficient (2πTD s) in the range of ~2–12 , are able to simultaneously reproduce our D 0 v 2 result and our previously published results for the D 0 nuclear modification factor.« less

  15. RHIC Au beam in Run 2014

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhang, S. Y.

    Au beam at the RHIC ramp in run 2014 is reviewed together with the run 2011 and run 2012. Observed bunch length and longitudinal emittance are compared with the IBS simulations. The IBS growth rate of the longitudinal emittance in run 2014 is similar to run 2011, and both are larger than run 2012. This is explained by the large transverse emittance at high intensity observed in run 2012, but not in run 2014. The big improvement of the AGS ramping in run 2014 might be related to this change. The importance of the injector intensity improvement in run 2014more » is emphasized, which gives rise to the initial luminosity improvement of 50% in run 2014, compared with the previous Au-Au run 2011. In addition, a modified IBS model, which is calibrated using the RHIC Au runs from 9.8 GeV/n to 100 GeV/n, is presented and used in the study.« less

  16. Ordered arrays of Au catalysts by FIB assisted heterogeneous dewetting.

    PubMed

    Benkouider, A; Ronda, A; David, T; Favre, L; Abbarchi, M; Naffouti, M; Osmond, J; Delobbe, A; Sudraud, P; Berbezier, I

    2015-12-18

    Synthesizing Au0.8Si0.2 nanocatalysts that are homogeneous in size and have controlled position is becoming a challenging and crucial prequisite for the fabrication of ordered semiconductor nanowires. In this study, Au0.8Si0.2 nanocatalysts are synthesized via dewetting of Au layers on Si(111) during thermal annealing in an ultra-high vacuum. In the first part of the paper, the mechanism of homogeneous dewetting is analyzed as a function of the Au-deposited thickness (h Au). We distinguish three different dewetting regimes: (I) for a low thickness ([Formula: see text]), a submonolyer coverage of Au is stabilized and there is no dewetting. (II) For an intermediate thickness ([Formula: see text]), there is both dewetting and Au0.8Si0.2 phase formation. The size and density of the Au0.8Si0.2 clusters are directly related to h Au. When cooling down to room temperature, the clusters decompose and reject the Si at the Au/Si substrate interface. (III) For a large thickness ([Formula: see text]), only dewetting takes place, without forming AuSi clusters. In this regime, the dewetting is kinetically controlled by the self-diffusion of Au (activation energy ∼0.43 eV) without evidence of an Si-alloying effect. As a practical consequence, when relying solely on the homogeneous dewetting of Au/Si(111) to form the Au0.8Si0.2 catalysts (without a supply of Si atoms from vapor), regime II should be used to obtain good size and density control. In the second part of the paper, a process for ordering the catalysts using focused ion beam-(FIB) assisted dewetting (heterogeneous dewetting) is developed. We show that no matter what the FIB milling conditions and the Au nominal thickness are, dewetting is promoted by ion beam irradiation and is accompanied by the formation of Au0.8Si0.2 droplets. The droplets preferentially form on the patterned areas, while in similar annealing conditions, they do not form on the unpatterned areas. This behavior is attributed to the larger Au

  17. Epitaxial growth of a mono-crystalline metastable AuIn layer at the Au/InP(001) interface

    NASA Astrophysics Data System (ADS)

    Renda, M.; Morita, K.

    1990-01-01

    Thermal annealing of a gold layer deposited on the InP(001)-p(2×4) surface has been studied in-situ by means of LEED, AES and RBS techniques and by post analysis of RBS-channeling and glancing incidence X-ray diffraction. A clean LEED pattern of p(2×2) spots was observed for the specimen annealed for 10 min at 300°C. The composition ratio of Au/In in the epitaxial compound layer was found to be 49/51 by RBS and several at% of P was also detected by post sputter-AES analysis. It was also found that the epitaxial layer shows a clear channeling dip for an incident ion beam which is aligned along the <001> axis of InP substrate. The glancing incidence X-ray diffraction analysis indicates diffraction peaks from the pseudo-orthorombic phase of AuIn. From these experimental results, it is concluded that the epitaxial Au-compound layer is a mono-crystalline metastable phase of AuIn, of which every three atomic rows of Au or In in the [110] direction would be situated on every four atomic rows in the [010] direction of the In(001) face of the InP crystal.

  18. A comparative study of the Au + H{sub 2}, Au{sup +} + H{sub 2}, and Au{sup −} + H{sub 2} systems: Potential energy surfaces and dynamics of reactive collisions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dorta-Urra, Anaís; Zanchet, Alexandre; Roncero, Octavio

    2015-04-21

    In order to study the Au{sup −} + H{sub 2} collision, a new global potential energy surface (PES) describing the ground electronic state of AuH{sub 2}{sup −} system is developed and compared with the PESs of the neutral [Zanchet et al., J. Chem. Phys. 132, 034301 (2010)] and cationic systems [Anaís et al., J. Chem. Phys. 135, 091102 (2011)]. We found that Au{sup −} − H{sub 2} presents a H-Au-H insertion minimum attributed to the stabilization of the LUMO 3b{sub 2} orbital, which can be considered as the preamble of the chemisorption well appearing in larger gold clusters. While themore » LUMO orbital is stabilized, the HOMO 6a{sub 1} is destabilized, creating a barrier at the geometry where the energy orbitals’ curves are crossing. In the anion, this HOMO is doubly occupied, while in the neutral system is half-filled and completely empty in the cation, explaining the gradual disappearance of the well and the barrier as the number of electrons decreases. The cation presents a well in the entrance channel partially explained by electrostatic interactions. The three systems’ reactions are highly endothermic, by 1.66, 2.79, and 3.23 eV for AuH, AuH{sup +}, and AuH{sup −} products, respectively. The reaction dynamics is studied using quasi-classical trajectory method for the three systems. The one corresponding to the anionic system is new in this work. Collision energies between 1.00 and 8.00 eV, measured for the cation, are in good agreement with the simulated cross section for the AuH{sup +}. It was also found that the total fragmentation, in three atoms, competes becoming dominant at sufficiently high energy. Here, we study the competition between the two different reaction pathways for the anionic, cationic, and neutral species, explaining the differences using a simple model based on the topology of the potential energy surfaces.« less

  19. Non-flow correlations and elliptic flow fluctuations in Au+Au collisions at sNN=200 GeV

    NASA Astrophysics Data System (ADS)

    Alver, B.; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Busza, W.; Carroll, A.; Chai, Z.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Halliwell, C.; Hamblen, J.; Hauer, M.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Li, W.; Lin, W. T.; Loizides, C.; Manly, S.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Reed, C.; Roland, C.; Roland, G.; Sagerer, J.; Seals, H.; Sedykh, I.; Smith, C. E.; Stankiewicz, M. A.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Walters, P.; Wenger, E.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wysłouch, B.

    2010-03-01

    This article presents results on event-by-event elliptic flow fluctuations in Au+Au collisions at sNN= 200 GeV, where the contribution from non-flow correlations has been subtracted. An analysis method is introduced to measure non-flow correlations, relying on the assumption that non-flow correlations are most prominent at short ranges (|Δη|<2). Assuming that non-flow correlations are of the order that is observed in p+p collisions for long-range correlations (|Δη|>2), relative elliptic flow fluctuations of approximately 30-40% are observed. These results are consistent with predictions based on spatial fluctuations of the participating nucleons in the initial nuclear overlap region. It is found that the long-range non-flow correlations in Au+Au collisions would have to be more than an order of magnitude stronger compared to the p+p data to lead to the observed azimuthal anisotropy fluctuations with no intrinsic elliptic flow fluctuations.

  20. Optical and electrical properties of colloidal (spherical Au)-(spinel ferrite nanorod) heterostructures

    NASA Astrophysics Data System (ADS)

    George, Chandramohan; Genovese, Alessandro; Qiao, Fen; Korobchevskaya, Kseniya; Comin, Alberto; Falqui, Andrea; Marras, Sergio; Roig, Anna; Zhang, Yang; Krahne, Roman; Manna, Liberato

    2011-11-01

    We report here a simple synthetic route to Au-FexOy heterostructures in which spinel ferrite (FexOy) grows as a nanorod on a spherical gold (Au) seed. The large red shift in the plasmon resonance in the heterostructures could be explained by a dielectric effect (although we could not entirely exclude a contribution due to electron transfer from Au to defect states at the Au-FexOy interface), while the magnetic properties of the Au-FexOy heterostructures were basically the same as those of the corresponding nanocrystals after Au leaching. In films of Au-FexOy heterostructures the electrical conductivity appeared to be mediated by the Au domains.We report here a simple synthetic route to Au-FexOy heterostructures in which spinel ferrite (FexOy) grows as a nanorod on a spherical gold (Au) seed. The large red shift in the plasmon resonance in the heterostructures could be explained by a dielectric effect (although we could not entirely exclude a contribution due to electron transfer from Au to defect states at the Au-FexOy interface), while the magnetic properties of the Au-FexOy heterostructures were basically the same as those of the corresponding nanocrystals after Au leaching. In films of Au-FexOy heterostructures the electrical conductivity appeared to be mediated by the Au domains. Electronic supplementary information (ESI) available: TEM/HRTEM images of (i) aliquots at the earliest stages of the growth of Au-FexOy HSs; (ii) Au-FexOy HSs synthesized at low DDAB concentrations; (iii) spherical iron oxide nanocrystals synthesized under the same conditions as the HSs, but in the absence of Au seeds; (iv) Au-FexOy urchin like nanostructures, also after attempts to leach out Au; (v) Au-FexOy HSs after treatment with hydrazine; (vi) FexOy HSs after Au leaching from Au-FexOy HSs; additional optical absorption spectra; additional I-V curves, also from films made of Au-FexOy dumbbells; and additional SEM images; vii) X-ray diffraction (XRD) pattern of a sample of Au

  1. Measurement of D0 Azimuthal Anisotropy at Midrapidity in Au +Au Collisions at √{sN N }=200 GeV

    NASA Astrophysics Data System (ADS)

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Ajitanand, N. N.; Alekseev, I.; Anderson, D. M.; Aoyama, R.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Ashraf, M. U.; Attri, A.; Averichev, G. S.; Bai, X.; Bairathi, V.; Behera, A.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandenburg, J. D.; Brandin, A. V.; Brown, D.; Bunzarov, I.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chankova-Bunzarova, N.; Chatterjee, A.; Chattopadhyay, S.; Chen, X.; Chen, J. H.; Chen, X.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Elsey, N.; Engelage, J.; Eppley, G.; Esha, R.; Esumi, S.; Evdokimov, O.; Ewigleben, J.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Federicova, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Finch, E.; Fisyak, Y.; Flores, C. E.; Fulek, L.; Gagliardi, C. A.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Gupta, S.; Guryn, W.; Hamad, A. I.; Hamed, A.; Harlenderova, A.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Horvat, S.; Huang, T.; Huang, B.; Huang, X.; Huang, H. Z.; Humanic, T. J.; Huo, P.; Igo, G.; Jacobs, W. W.; Jentsch, A.; Jia, J.; Jiang, K.; Jowzaee, S.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z.; Kikoła, D. P.; Kisel, I.; Kisiel, A.; Kochenda, L.; Kocmanek, M.; Kollegger, T.; Kosarzewski, L. K.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kulathunga, N.; Kumar, L.; Kvapil, J.; Kwasizur, J. H.; Lacey, R.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, X.; Li, C.; Li, W.; Li, Y.; Lidrych, J.; Lin, T.; Lisa, M. A.; Liu, H.; Liu, P.; Liu, Y.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, S.; Luo, X.; Ma, G. L.; Ma, L.; Ma, Y. G.; Ma, R.; Magdy, N.; Majka, R.; Mallick, D.; Margetis, S.; Markert, C.; Matis, H. S.; Meehan, K.; Mei, J. C.; Miller, Z. W.; Minaev, N. G.; Mioduszewski, S.; Mishra, D.; Mizuno, S.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nasim, Md.; Nayak, T. K.; Nelson, J. M.; Nie, M.; Nigmatkulov, G.; Niida, T.; Nogach, L. V.; Nonaka, T.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V. A.; Olvitt, D.; Page, B. S.; Pak, R.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Pile, P.; Pluta, J.; Poniatowska, K.; Porter, J.; Posik, M.; Poskanzer, A. M.; Pruthi, N. K.; Przybycien, M.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Ray, R. L.; Reed, R.; Rehbein, M. J.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Roth, J. D.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Salur, S.; Sandweiss, J.; Saur, M.; Schambach, J.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Schweid, B. R.; Seger, J.; Sergeeva, M.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, A.; Sharma, M. K.; Shen, W. Q.; Shi, Z.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Singha, S.; Skoby, M. J.; Smirnov, N.; Smirnov, D.; Solyst, W.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Strikhanov, M.; Stringfellow, B.; Sugiura, T.; Sumbera, M.; Summa, B.; Sun, Y.; Sun, X. M.; Sun, X.; Surrow, B.; Svirida, D. N.; Szelezniak, M. A.; Tang, A. H.; Tang, Z.; Taranenko, A.; Tarnowsky, T.; Tawfik, A.; Thäder, J.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Todoroki, T.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Trzeciak, B. A.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vasiliev, A. N.; Videbæk, F.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, G.; Wang, Y.; Wang, F.; Wang, Y.; Webb, J. C.; Webb, G.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xiao, Z. G.; Xie, W.; Xie, G.; Xu, J.; Xu, N.; Xu, Q. H.; Xu, Y. F.; Xu, Z.; Yang, Y.; Yang, Q.; Yang, C.; Yang, S.; Ye, Z.; Ye, Z.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, Z.; Zhang, X. P.; Zhang, J. B.; Zhang, S.; Zhang, J.; Zhang, Y.; Zhang, J.; Zhang, S.; Zhao, J.; Zhong, C.; Zhou, L.; Zhou, C.; Zhu, X.; Zhu, Z.; Zyzak, M.; STAR Collaboration

    2017-05-01

    We report the first measurement of the elliptic anisotropy (v2) of the charm meson D0 at midrapidity (|y |<1 ) in Au +Au collisions at √{sN N}=200 GeV . The measurement was conducted by the STAR experiment at RHIC utilizing a new high-resolution silicon tracker. The measured D0 v2 in 0%-80% centrality Au +Au collisions can be described by a viscous hydrodynamic calculation for a transverse momentum (pT) of less than 4 GeV /c . The D0 v2 as a function of transverse kinetic energy (mT-m0, where mT=√{pT2+m02 }) is consistent with that of light mesons in 10%-40% centrality Au +Au collisions. These results suggest that charm quarks have achieved local thermal equilibrium with the medium created in such collisions. Several theoretical models, with the temperature-dependent, dimensionless charm spatial diffusion coefficient (2 π T Ds) in the range of ˜2 - 12 , are able to simultaneously reproduce our D0 v2 result and our previously published results for the D0 nuclear modification factor.

  2. Kaon femtoscopy in Au+Au collisions at √SNN = 200 GeV at the STAR experiment

    NASA Astrophysics Data System (ADS)

    Lidrych, Jindřich

    2018-02-01

    In this proceedings, the STAR preliminary results on femtoscopic correlations of identical kaons from Au+Au collisions at =200 GeV are presented. The measured kaon source radii are studied as a function of collision energy as well as centrality and transverse pair mass mT. In addition, extracted kaon blast-wave freeze-out parameters are presented.

  3. Molecular dynamics simulations on the effect of size and shape on the interactions between negative Au18(SR)14, Au102(SR)44 and Au144(SR)60 nanoparticles in physiological saline.

    PubMed

    Villareal, Oscar D; Rodriguez, Roberto A; Yu, Lili; Wambo, Thierry O

    2016-08-20

    Molecular dynamics simulations employing all-atom force fields have become a reliable way to study binding interactions quantitatively for a wide range of systems. In this work, we employ two recently developed methods for the calculation of dissociation constants K D between gold nanoparticles (AuNPs) of different sizes in a near-physiological environment through the potential of mean force (PMF) formalism: the method of geometrical restraints developed by Woo et al. and formalized by Gumbart et al. and the method of hybrid Steered Molecular Dynamics (hSMD). Obtaining identical results (within the margin of error) from both approaches on the negatively charged Au 18 (SR) 14 NP, functionalized by the negatively charged 4-mercapto-benzoate (pMBA) ligand, we draw parallels between their energetic and entropic interactions. By applying the hSMD method on Au 102 (SR) 44 and Au 144 (SR) 60 , both of them near-spherical in shape and functionalized by pMBA, we study the effects of size and shape on the binding interactions. Au 18 binds weakly with K D = 13 mM as a result of two opposing effects: its large surface curvature hindering the formation of salt bridges, and its large ligand density on preferential orientations favoring their formation. On the other hand, Au 102 binds more strongly with K D = 30 μM and Au 144 binds the strongest with K D = 3.2 nM .

  4. Role of Au-C Interactions on the Catalytic Activity of Au Nanoparticles Supported on TiC(001) Towards Molecular Oxygen Dissociation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rodriguez, J.A.; Feria, L.; Jirsak, T.

    2010-03-10

    High-resolution photoemission and density functional calculations on realistic slab surface models were used to study the interaction and subsequent dissociation of O{sub 2} with Au nanoparticles supported on TiC(001). The photoemission results indicate that at 150 K O{sub 2} adsorbs molecularly on the supported gold nanoparticles, and upon heating to temperatures above 200 K the O{sub 2} {yields} 2O reaction takes place with migration of atomic oxygen to the TiC(001) substrate. The addition of Au to TiC(001) substantially enhances the rate of O{sub 2} dissociation at room temperature. The reactivity of Au nanoparticles supported on TiC(001) toward O{sub 2} dissociationmore » is much larger than that of similar nanoparticles supported either on TiO{sub 2}(110) or MgO(001) surfaces, where the cleavage of O-O bonds is very difficult. Density functional calculations carried out on large supercells show that the contact of Au with TiC(001) is essential for charge polarization and an enhancement in the chemical activity of Au. Small two-dimensional particles which expose Au atoms in contact with TiC(001) are the most reactive. While O{sub 2} prefers binding to Au sites, the O atoms interact more strongly with the TiC(001) surface. The oxygen species active during the low-temperature (<200 K) oxidation of carbon monoxide on Au/TiC(001) is chemisorbed O{sub 2}. Once atomic O binds to TiC(001), the chemisorption bond is so strong that temperatures well above 400 K are necessary to remove the O adatoms from the TiC(001) substrate by direct reaction with CO. The high reactivity of Au/TiC(001) toward O{sub 2} at low-temperature opens the route for the transformation of alcohols and amines on the supported Au nanoparticles.« less

  5. Role of Au-C Interactions on the Catalytic Activity of Au Nanoparticles Supported on TiC(001) toward Molecular Oxygen Dissociation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rodriguez, J.; Feria, L; Jirsak, T

    2010-01-01

    High-resolution photoemission and density functional calculations on realistic slab surface models were used to study the interaction and subsequent dissociation of O{sub 2} with Au nanoparticles supported on TiC(001). The photoemission results indicate that at 150 K O{sub 2} adsorbs molecularly on the supported gold nanoparticles, and upon heating to temperatures above 200 K the O{sub 2} {yields} 2O reaction takes place with migration of atomic oxygen to the TiC(001) substrate. The addition of Au to TiC(001) substantially enhances the rate of O{sub 2} dissociation at room temperature. The reactivity of Au nanoparticles supported on TiC(001) toward O{sub 2} dissociationmore » is much larger than that of similar nanoparticles supported either on TiO{sub 2}(110) or MgO(001) surfaces, where the cleavage of O-O bonds is very difficult. Density functional calculations carried out on large supercells show that the contact of Au with TiC(001) is essential for charge polarization and an enhancement in the chemical activity of Au. Small two-dimensional particles which expose Au atoms in contact with TiC(001) are the most reactive. While O{sub 2} prefers binding to Au sites, the O atoms interact more strongly with the TiC(001) surface. The oxygen species active during the low-temperature (<200 K) oxidation of carbon monoxide on Au/TiC(001) is chemisorbed O{sub 2}. Once atomic O binds to TiC(001), the chemisorption bond is so strong that temperatures well above 400 K are necessary to remove the O adatoms from the TiC(001) substrate by direct reaction with CO. The high reactivity of Au/TiC(001) toward O{sub 2} at low-temperature opens the route for the transformation of alcohols and amines on the supported Au nanoparticles.« less

  6. Highly sensitive aptasensor based on synergetic catalysis activity of MoS2-Au-HE composite using cDNA-Au-GOD for signal amplification.

    PubMed

    Song, Hai-Yan; Kang, Tian-Fang; Lu, Li-Ping; Cheng, Shui-Yuan

    2017-03-01

    Single or few-layer nanosheets of MoS 2 (MoS 2 nanosheets) and a composite composed of MoS 2 nanosheets, Au nanoparticles (AuNPs) and hemin (HE) (denoted as MoS 2 -Au-HE) were prepared. The composites possessed high synergetic catalysis activity towards the electroreduction of hydrogen peroxide. Furthermore, glucose oxidase (GOD) and AuNPs were used as marker of the complementary DNA (cDNA) strand of kanamycin aptamer to prepare a conjugate (reffered as cDNA-Au-GOD) that was designed as the signal probe. Both cDNA-Au-GOD and MoS 2 -Au-HE were applied to fabricate aptasensor for kanamycin. MoS 2 -Au-HE acted as solid platform for kanamycin aptamer and signal transmitters. AuNPs were employed as the supporter of cDNA and GOD which catalyze dissolved oxygen to produce hydrogen peroxide in the presence of glucose. Then cathodic peak current of H 2 O 2 was recorded by differential pulse voltammetry (DPV). The electrochemical reduction of H 2 O 2 was catalyzed by MoS 2 -Au-HE that was modified onto the surface of a glassy carbon electrode (GCE). The cathodic peak current of H 2 O 2 was highly linearly decreased with an increase of kanamycin concentrations from 1.0ng/L to 1.0×10 5 ng/L, with a detection limit of 0.8ng/L. This aptasensor can be used to detect kanamycin in milk with high specificity, sensitivity and selectivity. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Synthesis and characterization of Au incorporated Alq3 nanowires

    NASA Astrophysics Data System (ADS)

    Khan, Mohammad Bilal; Ahmad, Sultan; Parwaz, M.; Rahul, Khan, Zishan H.

    2018-05-01

    We report the synthesis and characterization of pure and Au incorporated Alq3 nanowires. These nanowires are synthesized using thermal vapor transport method. The luminescence intensity of Au incorporated Alq3 nanowires are recorded to be higher than that of pure Alq3 nanowires, which is found to increase with the increase in Au concentration. Fluorescence quenching is also observed when Au concentration is increased beyond the certain limit.

  8. Transverse momentum and centrality dependence of high-pT nonphotonic electron suppression in Au+Au collisions at sqrt[s NN]=200 GeV.

    PubMed

    Abelev, B I; Aggarwal, M M; Ahammed, Z; Anderson, B D; Arkhipkin, D; Averichev, G S; Bai, Y; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Baumgart, S; Belaga, V V; Bellingeri-Laurikainen, A; Bellwied, R; Benedosso, F; Betts, R R; Bhardwaj, S; Bhasin, A; Bhati, A K; Bichsel, H; Bielcik, J; Bielcikova, J; Bland, L C; Blyth, S-L; Bombara, M; Bonner, B E; Botje, M; Bouchet, J; Brandin, A V; Bravar, A; Burton, T P; Bystersky, M; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca Sánchez, M; Callner, J; Catu, O; Cebra, D; Chajecki, Z; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, J H; Chen, J Y; Cheng, J; Cherney, M; Chikanian, A; Christie, W; Chung, S U; Coffin, J P; Cormier, T M; Cosentino, M R; Cramer, J G; Crawford, H J; Das, D; Dash, S; Daugherity, M; de Moura, M M; Dedovich, T G; Dephillips, M; Derevschikov, A A; Didenko, L; Dietel, T; Djawotho, P; Dogra, S M; Dong, X; Drachenberg, J L; Draper, J E; Du, F; Dunin, V B; Dunlop, J C; Dutta Mazumdar, M R; Eckardt, V; Edwards, W R; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Estienne, M; Fachini, P; Fatemi, R; Fedorisin, J; Feng, A; Filip, P; Finch, E; Fine, V; Fisyak, Y; Fu, J; Gagliardi, C A; Gaillard, L; Ganti, M S; Garcia-Solis, E; Ghazikhanian, V; Ghosh, P; Gorbunov, Y G; Gos, H; Grebenyuk, O; Grosnick, D; Guertin, S M; Guimaraes, K S F F; Gupta, N; Haag, B; Hallman, T J; Hamed, A; Harris, J W; He, W; Heinz, M; Henry, T W; Heppelmann, S; Hippolyte, B; Hirsch, A; Hjort, E; Hoffman, A M; Hoffmann, G W; Hofman, D; Hollis, R; Horner, M J; Huang, H Z; Hughes, E W; Humanic, T J; Igo, G; Iordanova, A; Jacobs, P; Jacobs, W W; Jakl, P; Jia, F; Jones, P G; Judd, E G; Kabana, S; Kang, K; Kapitan, J; Kaplan, M; Keane, D; Kechechyan, A; Kettler, D; Khodyrev, V Yu; Kim, B C; Kiryluk, J; Kisiel, A; Kislov, E M; Klein, S R; Knospe, A G; Kocoloski, A; Koetke, D D; Kollegger, T; Kopytine, M; Kotchenda, L; Kouchpil, V; Kowalik, K L; Kravtsov, P; Kravtsov, V I; Krueger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kurnadi, P; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; Lapointe, S; Laue, F; Lauret, J; Lebedev, A; Lednicky, R; Lee, C-H; Lehocka, S; LeVine, M J; Li, C; Li, Q; Li, Y; Lin, G; Lin, X; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, H; Liu, J; Liu, L; Ljubicic, T; Llope, W J; Longacre, R S; Love, W A; Lu, Y; Ludlam, T; Lynn, D; Ma, G L; Ma, J G; Ma, Y G; Magestro, D; Mahapatra, D P; Majka, R; Mangotra, L K; Manweiler, R; Margetis, S; Markert, C; Martin, L; Matis, H S; Matulenko, Yu A; McClain, C J; McShane, T S; Melnick, Yu; Meschanin, A; Millane, J; Miller, M L; Minaev, N G; Mioduszewski, S; Mironov, C; Mischke, A; Mitchell, J; Mohanty, B; Morozov, D A; Munhoz, M G; Nandi, B K; Nattrass, C; Nayak, T K; Nelson, J M; Nepali, N S; Netrakanti, P K; Nogach, L V; Nurushev, S B; Odyniec, G; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Pachr, M; Pal, S K; Panebratsev, Y; Pavlinov, A I; Pawlak, T; Peitzmann, T; Perevoztchikov, V; Perkins, C; Peryt, W; Phatak, S C; Planinic, M; Pluta, J; Poljak, N; Porile, N; Poskanzer, A M; Potekhin, M; Potrebenikova, E; Potukuchi, B V K S; Prindle, D; Pruneau, C; Putschke, J; Qattan, I A; Raniwala, R; Raniwala, S; Ray, R L; Relyea, D; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Rose, A; Roy, C; Ruan, L; Russcher, M J; Sahoo, R; Sakrejda, I; Sakuma, T; Salur, S; Sandweiss, J; Sarsour, M; Sazhin, P S; Schambach, J; Scharenberg, R P; Schmitz, N; Seger, J; Selyuzhenkov, I; Seyboth, P; Shabetai, A; Shahaliev, E; Shao, M; Sharma, M; Shen, W Q; Shimanskiy, S S; Sichtermann, E P; Simon, F; Singaraju, R N; Smirnov, N; Snellings, R; Sorensen, P; Sowinski, J; Speltz, J; Spinka, H M; Srivastava, B; Stadnik, A; Stanislaus, T D S; Staszak, D; Stock, R; Strikhanov, M; Stringfellow, B; Suaide, A A P; Suarez, M C; Subba, N L; Sumbera, M; Sun, X M; Sun, Z; Surrow, B; Symons, T J M; Szanto de Toledo, A; Takahashi, J; Tang, A H; Tarnowsky, T; Thomas, J H; Timmins, A R; Timoshenko, S; Tokarev, M; Trainor, T A; Trentalange, S; Tribble, R E; Tsai, O D; Ulery, J; Ullrich, T; Underwood, D G; Van Buren, G; van der Kolk, N; van Leeuwen, M; Vander Molen, A M; Varma, R; Vasilevski, I M; Vasiliev, A N; Vernet, R; Vigdor, S E; Viyogi, Y P; Vokal, S; Voloshin, S A; Waggoner, W T; Wang, F; Wang, G; Wang, J S; Wang, X L; Wang, Y; Watson, J W; Webb, J C; Westfall, G D; Wetzler, A; Whitten, C; Wieman, H; Wissink, S W; Witt, R; Wu, J; Wu, Y; Xu, N; Xu, Q H; Xu, Z; Yepes, P; Yoo, I-K; Yue, Q; Yurevich, V I; Zhan, W; Zhang, H; Zhang, W M; Zhang, Y; Zhang, Z P; Zhao, Y; Zhong, C; Zhou, J; Zoulkarneev, R; Zoulkarneeva, Y; Zubarev, A N; Zuo, J X

    2007-05-11

    The STAR collaboration at the BNL Relativistic Heavy-Ion Collider (RHIC) reports measurements of the inclusive yield of nonphotonic electrons, which arise dominantly from semileptonic decays of heavy flavor mesons, over a broad range of transverse momenta (1.2Au, and Au+Au collisions at sqrt[s_{NN}]=200 GeV. The nonphotonic electron yield exhibits an unexpectedly large suppression in central Au+Au collisions at high p(T), suggesting substantial heavy-quark energy loss at RHIC. The centrality and p(T) dependences of the suppression provide constraints on theoretical models of suppression.

  9. Microstructure and opto-electronic properties of Sn-rich Au-Sn diffusive solders

    NASA Astrophysics Data System (ADS)

    Rerek, T.; Skowronski, L.; Kobierski, M.; Naparty, M. K.; Derkowska-Zielinska, B.

    2018-09-01

    Microstructural and opto-electronic properties of Au ⧹ Sn and Sn ⧹ Au bilayers, obtained by sequential evaporating of metals on the Si substrate, were investigated by means of atomic force microscopy, X-ray diffraction and spectroscopic ellipsometry. Thicknesses of individual films were established to obtain the atomic ratio of Au:Sn atoms 1:1, 1:2 and 1:4, which were favor the formation of AuSn, AuSn2 and AuSn4, respectively. However, the produced intermatallic compounds were detected as AuSn and AuSn2. Additionally, the unbounded Sn was found. The sequence of deposition of Au and Sn films as well as their thickness strongly affect on the composition, microstructure, optical and electrical properties of the produced layers. The Au ⧹ Sn (Sn on the top) layers were more smooth than Sn ⧹ Au (Au on the top) films. Generally, the Au ⧹ Sn layers exhibit a better electrical and optical properties than Sn ⧹ Au films. The optical parameters: plasma energy, free-carrier damping, mean relaxation time of conduction electrons and optical resistivity were determined from the effective complex dielectric function of the formed Au, Sn and Au-Sn films. The optical resistivity values are in the range from 17.8 μΩ cm to 85.1 μΩ cm and from 29.6 μΩ cm to 113.3 μΩ cm for Au ⧹ Sn and Sn ⧹ Au layers, respectively.

  10. UV and visible light photocatalytic activity of Au/TiO2 nanoforests with Anatase/Rutile phase junctions and controlled Au locations.

    PubMed

    Yu, Yang; Wen, Wei; Qian, Xin-Yue; Liu, Jia-Bin; Wu, Jin-Ming

    2017-01-24

    To magnify anatase/rutile phase junction effects through appropriate Au decorations, a facile solution-based approach was developed to synthesize Au/TiO 2 nanoforests with controlled Au locations. The nanoforests cons®isted of anatase nanowires surrounded by radially grown rutile branches, on which Au nanoparticles were deposited with preferred locations controlled by simply altering the order of the fabrication step. The Au-decoration increased the photocatalytic activity under the illumination of either UV or visible light, because of the beneficial effects of either electron trapping or localized surface plasmon resonance (LSPR). Gold nanoparticles located preferably at the interface of anatase/rutile led to a further enhanced photocatalytic activity. The appropriate distributions of Au nanoparticles magnify the beneficial effects arising from the anatase/rutile phase junctions when illuminated by UV light. Under the visible light illumination, the LSPR effect followed by the consecutive electron transfer explains the enhanced photocatalysis. This study provides a facile route to control locations of gold nanoparticles in one-dimensional nanostructured arrays of multiple-phases semiconductors for achieving a further increased photocatalytic activity.

  11. The Influence of Interstitial Ga and Interfacial Au (sub 2)P (sub 3) on the Electrical and Metallurgical Behavior of Au-Contacted III-V Semiconductors

    NASA Technical Reports Server (NTRS)

    Weizer, Victor G.; Fatemi, Navid S.

    1991-01-01

    The introduction of a very small amount of Ga into Au contact metallization on InP is shown to have a significant effect on both the metallurgical and electrical behavior of that contact system. Ga atoms in the interstices of the Au lattice are shown to be effective in preventing the solid state reactions that normally take place between Au and InP during contact sintering. In addition to suppressing the metallurgical interaction, the presence of small amounts of Ga is shown to cause an order of magnitude reduction in the specific contact resistivity. Evidence is presented that the reactions of GaP and GaAs with Au contacts are also drastically affected by the presence of Ga. The sintering behavior of the Au-GaP and the Au-GaAs systems (as contrasted with that of the Au-InP system) is explained as due to the presence of interstitial Ga in the contact metallization. Finally the large, two-to-three order of magnitude drop in the contact resistance that occurs in the Au-InP system upon sintering at 400 degrees Centigrade is shown to be a result of the formation of an Au (sub 2) P (sub 3) layer at the metal-semiconductor interface. Contact resistivities in the 10 (sup -6) ohm square centimeter range are obtained for as-deposited Au on InP when a thin (20 Angstrom) layer of Au (sub 2) P (sub 3) is introduced between the InP and the Au contacts.

  12. TPS, CA 19-9, VEGF-A, and CEA as diagnostic and prognostic factors in patients with mass lesions in the pancreatic head.

    PubMed

    Sandblom, Gabriel; Granroth, Sofie; Rasmussen, Ib Christian

    2008-01-01

    Although numerous tumour markers are available for periampullary tumours, including pancreatic cancer, their specificity and sensitivity have been questioned. To assess the diagnostic and prognostic values of tissue polypeptide specific antigen (TPS), carbohydrate antigen 19-9 (CA 19-9), vascular endothelial growth factor (VEGF-A), and carcinoembryonic antigen (CEA) we took serum samples in 56 patients with mass lesions in the pancreatic head. Among these patients, further investigations revealed pancreatic cancer in 20 patients, other malignant diseases in 12 and benign conditions in 24. Median CEA in all patients was 3.4 microg/L (range 0.5-585.0), median CA 19-9 was105 kU/L (range 0.6-1 300 00), median TPS 123.5 U/L (range 15.0-3350) and median VEGF-A 132.5 ng/L (range 60.0-4317). Area under the curve was 0.747, standard error (standard error [SE] =0.075) for CEA, 0.716 (SE=0.078) for CA 19-9 and 0.822 (SE=0.086) for TPS in ROC plots based on the ability of the tumours to distinguish between benign and malignant conditions. None of the markers significantly predicted survival in the subgroup of patients with pancreatic cancer. Our study shows that the markers may be used as fairly reliable diagnostic tools, but cannot be used to predict survival.

  13. Identifying Au-based Te alloys for optical data storage

    NASA Astrophysics Data System (ADS)

    Wamwangi, D.; Detemple, R.; Woeltgens, H.-W.; Wuttig, M.; Zhang, X.

    2004-06-01

    Au18Sb23Te59 and Au19In26Te55 have been investigated to determine their suitability as phase change recording alloys. Recrystallization experiments identify Au18Sb23Te59 as a suitable phase change material with a recrystallization time of 110 ns and high optical contrast. Coupled to the high optical contrast is a considerable density increase of 4% upon crystallization which allows phase change recording for the Au18Sb23Te59 alloy. On the other hand no recrystallization has been observed optically for Au19In26Te55 due to its low optical contrast of less than 1%. This is related to a lower density contrast of 2%. The crystallization for the Au18Sb23Te59 and Au19In26Te55 alloys observed from temperature-dependent sheet resistance measurements have yielded transition temperatures of 113 and 175 °C, and activation barriers of 1.61±0.01 eV and 2.42±0.02 eV, respectively. We report a cubic structure (a=2.99±0.002 Å) for the Au18Sb23Te59 alloy and a chalcopyrite structure (a=6.50±0.018 Å and 12.27±0.025 Å) for the Au19In26Te55 material. These results confirm that suitable phase change alloys possess cubic structures rather than the chalcopyrite structure typical for sp3 bonded semiconductors.

  14. Identification of Au–S complexes on Au(100)

    DOE PAGES

    Walen, Holly; Liu, Da -Jiang; Oh, Junepyo; ...

    2016-01-25

    In this study, using a combination of scanning tunneling microscopy and density functional theory (DFT) calculations, we have identified a set of related Au–S complexes that form on Au(100), when sulfur adsorbs and lifts the hexagonal surface reconstruction. The predominant complex is diamond-shaped with stoichiometry Au 4S 5. All of the complexes can be regarded as combinations of S–Au–S subunits. The complexes exist within, or at the edges of, p(2 × 2) sulfur islands that cover the unreconstructed Au regions, and are observed throughout the range of S coverage examined in this study, 0.009 to 0.12 monolayers. A qualitative modelmore » is developed which incorporates competitive formation of complexes, Au rafts, and p(2 × 2) sulfur islands, as Au atoms are released by the surface structure transformation.« less

  15. A comparative study of the electrostatic potential of fullerene-like structures of Au 32 and Au 42

    NASA Astrophysics Data System (ADS)

    Wang, Dong-Lai; Sun, Xiao-Ping; Shen, Hong-Tao; Hou, Dong-Yan; Zhai, Yu-Chun

    2008-05-01

    By using density functional theory calculations, it is found that the most negative MEP inside the gold cage occurs at the center of the sphere. The largest regions with the most negative MEP outside the sphere are localized in the neighborhood of the bridge sites and the vertex regions of the five-coordinated are more positive. The absolute values of the most negative potentials in both the inner and outer cages as well as the vertex regions of the five-coordinated of Au 32 structure are much larger than those of Au 42, which means Au 32 is preferable for electrophilic attack or nucleophilic processes.

  16. Au/NiFe/M(Au, MoS2, graphene) trilayer magnetoplasmonics DNA-hybridized sensors with high record of sensitivity

    NASA Astrophysics Data System (ADS)

    Faridi, Ehsan; Moradi, Maryam; Ansari, Narges; Ghasemi, Amir Hossein Baradaran; Afshar, Amir; Mohseni, Seyed Majid

    2017-12-01

    The demonstration of biosensors based on the surface plasmon effect holds promise for future high-sensitive electrodeless biodetection. The combination of magnetic effects with surface plasmon waves brings additional freedom to improve sensitivity and signal selectivity. Stacking biosensors with two-dimensional (2-D) materials, e.g., graphene (Gr) and MoS2, can influence plasmon waves and facilitate surface physiochemical properties as additional versatility aspects. We demonstrate magnetoplasmonic biosensors through the detuning of surface plasmon oscillation modes affected by magnetic effect via the presence of the NiFe (Py) layer and different light absorbers of Gr, MoS2, and Au ultrathin layers in three stacks of Au/Py/M(MoS2, Gr, Au) trilayers. We found minimum reflection, resonance angle shift, and transverse magneto-optical Kerr effect (TMOKE) responses of all sensors in the presence of the ss-DNA monolayer. Very few changes of ˜5×10-7 in the ss-DNA's refractive index result in valuable TMOKE response. We found that the presence of three-layer Gr and two-layer MoS2 on top of the Au/Py bilayer can dramatically increase the sensitivity by nine and four times, respectively, than the conventional Au/Co/Au trilayer. Our results show the highest reported DNA sensitivity based on the coupling of light with 2-D materials in magnetoplasmonic devices.

  17. Size-induced chemical and magnetic ordering in individual Fe-Au nanoparticles.

    PubMed

    Mukherjee, Pinaki; Manchanda, Priyanka; Kumar, Pankaj; Zhou, Lin; Kramer, Matthew J; Kashyap, Arti; Skomski, Ralph; Sellmyer, David; Shield, Jeffrey E

    2014-08-26

    Formation of chemically ordered compounds of Fe and Au is inhibited in bulk materials due to their limited mutual solubility. However, here we report the formation of chemically ordered L12-type Fe3Au and FeAu3 compounds in Fe-Au sub-10 nm nanoparticles, suggesting that they are equilibrium structures in size-constrained systems. The stability of these L12-ordered Fe3Au and FeAu3 compounds along with a previously discovered L10-ordered FeAu has been explained by a size-dependent equilibrium thermodynamic model. Furthermore, the spin ordering of these three compounds has been computed using ab initio first-principle calculations. All ordered compounds exhibit a substantial magnetization at room temperature. The Fe3Au had a high saturation magnetization of about 143.6 emu/g with a ferromagnetic spin structure. The FeAu3 nanoparticles displayed a low saturation magnetization of about 11 emu/g. This suggests a antiferromagnetic spin structure, with the net magnetization arising from uncompensated surface spins. First-principle calculations using the Vienna ab initio simulation package (VASP) indicate that ferromagnetic ordering is energetically most stable in Fe3Au, while antiferromagnetic order is predicted in FeAu and FeAu3, consistent with the experimental results.

  18. Non Photonic e-D{sup 0} correlations in p+p and Au+Au collisions at {radical}(S{sub NN} = 200 GeV)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Geromitsos, Artemios

    The sum of charm and beauty in Au+Au collisions at 200 GeV measured through non-photonic electrons, show similar suppression at high p{sub T} as light hadrons, in contrast to expectations based on the dead cone effect. To understand this observation, it is important to separate the charm and beauty components. Non-photonic electron-D{sup 0} and electron-hadron azimuthal angular correlations are used to disentangle the contributions from charm and beauty decays. The beauty contribution in p+p. collisions at 200 GeV is found to be comparable to charm at p{sub T}{approx}5.5 GeV, indicating that beauty may contribute significantly to the non photonic electronsmore » from heavy flavour decays in Au+Au data at high p{sub T}. Furthermore, we are employing microvertexing techniques, not used for the analysis of p+p collisions, in Au+Au collisions at 200 GeV. We present our analysis status of D{sub 0} meson reconstruction.« less

  19. Charged particle multiplicity fluctuations in Au+Au collisions at \\sqrt{s_{NN}} = 200\\, {\\rm GeV}

    NASA Astrophysics Data System (ADS)

    Wozniak, Krzysztof; PHOBOS Collaboration; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Chai, Z.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Holynski, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tang, J. L.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wolfs, F. L. H.; Wosiek, B.; Wuosmaa, A. H.; Wyslouch, B.

    2004-08-01

    This paper presents the first PHOBOS results on charged particle multiplicity fluctuations measured for Au+Au collisions at the highest RHIC energy within a wide pseudorapidity range of |eegr| < 3. The dependence on collision geometry is removed in the analysis by using the normalized difference between the number of particles in separate eegr bins. We compare our data to HIJING model predictions.

  20. A general and high-yield galvanic displacement approach to Au-M (M = Au, Pd, and Pt) core-shell nanostructures with porous shells and enhanced electrocatalytic performances.

    PubMed

    Kuai, Long; Geng, Baoyou; Wang, Shaozhen; Sang, Yan

    2012-07-23

    In this work, we utilize the galvanic displacement synthesis and make it a general and efficient method for the preparation of Au-M (M = Au, Pd, and Pt) core-shell nanostructures with porous shells, which consist of multilayer nanoparticles. The method is generally applicable to the preparation of Au-Au, Au-Pd, and Au-Pt core-shell nanostructures with typical porous shells. Moreover, the Au-Au isomeric core-shell nanostructure is reported for the first time. The lower oxidation states of Au(I), Pd(II), and Pt(II) are supposed to contribute to the formation of porous core-shell nanostructures instead of yolk-shell nanostructures. The electrocatalytic ethanol oxidation and oxygen reduction reaction (ORR) performance of porous Au-Pd core-shell nanostructures are assessed as a typical example for the investigation of the advantages of the obtained core-shell nanostructures. As expected, the Au-Pd core-shell nanostructure indeed exhibits a significantly reduced overpotential (the peak potential is shifted in the positive direction by 44 mV and 32 mV), a much improved CO tolerance (I(f)/I(b) is 3.6 and 1.63 times higher), and an enhanced catalytic stability in comparison with Pd nanoparticles and Pt/C catalysts. Thus, porous Au-M (M = Au, Pd, and Pt) core-shell nanostructures may provide many opportunities in the fields of organic catalysis, direct alcohol fuel cells, surface-enhanced Raman scattering, and so forth. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. ϕ Meson Spin Alignment and the Azimuthal Angle Dependence of Λ (Λ) Polarization in Au+Au collisions at RHIC

    NASA Astrophysics Data System (ADS)

    Tu, Biao

    2018-02-01

    Initial large global angular momentum in non-central relativistic heavy-ion collisions can produce strong vorticity, and through the spin-orbit coupling, causes the spin of particles to align with the system's global angular momentum. We present the azimuthal angle dependent (relative to the reaction plane) polarization for Λ and Λ in mid-central Au+Au collisions at = 200 GeV. We also present the ϕ meson spin alignment parameter, ρ00 in Au+Au collisions at = 19.6, 27, 39, 62.4 and 200 GeV. The implications of the results are discussed.

  2. Forward-backward multiplicity correlations in sNN=200 GeV Au+Au collisions

    NASA Astrophysics Data System (ADS)

    Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Chai, Z.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Hauer, M.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Mignerey, A. C.; Noucier, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Seals, H.; Sedykh, I.; Skulski, W.; Smith, C. E.; Stankiewicz, M. A.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tang, J.-L.; Tonjes, M. B.; Trzupek, A.; Vale, C.; Nieuwenhuizen, G. J. Van; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Wenger, E.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2006-07-01

    Forward-backward correlations of charged-particle multiplicities in symmetric bins in pseudorapidity are studied to gain insight into the underlying correlation structure of particle production in Au+Au collisions. The PHOBOS detector is used to measure integrated multiplicities in bins centered at η, defined within |η|<3, and covering intervals Δη. The variance σC2 of a suitably defined forward-backward asymmetry variable C is calculated as a function of η,Δη, and centrality. It is found to be sensitive to short-range correlations, and the concept of “clustering” is used to interpret comparisons to phenomenological models.

  3. Exploring the Photoreduction of Au(III) Complexes in the Gas-Phase

    NASA Astrophysics Data System (ADS)

    Marcum, Jesse C.; Kaufman, Sydney H.; Weber, J. Mathias

    2010-06-01

    We have used photodissociation spectroscopy to probe the electronic structure and photoreduction of Au(III) in gas-phase complexes containing Cl- and OH-. The gas-phase electronic spectrum of [AuCl_4]- closely resembles the aqueous solution spectrum, showing a lack of strong solvatochromic shifts. Substitution of Cl- ligands with OH- results in a strong blue shift, in agreement with ligand-field theory. Upon excitation, [AuCl_4]- can dissociate by loss of either one or two neutral Cl atoms, resulting in the reduction of gold from Au(III) to Au(II) and Au(I) respectively. The hydroxide substituted complex, [AuCl_2(OH)_2]-, demonstrates similar behavior but the only observable fragment channel is the loss of two neutral OH ligands, leading only to Au(I).

  4. Nucleon shadowing effects in Cu + Cu and Au + Au collisions at RHIC within the HIJING code

    NASA Astrophysics Data System (ADS)

    Abdel-Waged, Khaled; Felemban, Nuha

    2018-02-01

    The centrality dependence of pseudorapidity density of charged particles ({{{d}}{N}}{{ch}}/{{d}}η ) in Cu + Cu (Au + Au) collisions at Relativistic Heavy Ion Collider energy of \\sqrt{{s}{{NN}}}=22.4, 62.4 and 200 (19.6, 62.4 and 200) GeV, is investigated within an improved HIJING code. The standard HIJING model is enhanced by a prescription for collective nucleon-nucleon (NN) interactions and more modern parton distribution functions. The collective NN-interactions are used to induce both cascade and nucleon shadowing effects. We find collective cascade broadens the pseudorapidity distributions in the tails (at | η | > {y}{beam}) above 25%-30% collision centrality to be consistent with the {{{d}}{N}}{{ch}}/{{d}}η data at \\sqrt{{s}{{NN}}} =19.6,22.4,62.4 {GeV}. The overall contribution of nucleon shadowing is shown to depress the whole shape of {{{d}}{N}}{{ch}}/{{d}}η in the primary interaction region (at | η | < {y}{beam}) for semiperipheral (20%-25%) and peripheral (≥slant 35 % {--}40 % ) Cu + Cu (Au + Au) interactions at \\sqrt{{s}{{NN}}}=200 {GeV}, in accordance with the PHOBOS data.

  5. Dual structural transition in small nanoparticles of Cu-Au alloy

    NASA Astrophysics Data System (ADS)

    Gafner, Yuri; Gafner, Svetlana; Redel, Larisa; Zamulin, Ivan

    2018-02-01

    Cu-Au alloy nanoparticles are known to be widely used in the catalysis of various chemical reactions as it was experimentally defined that in many cases the partial substitution of copper with gold increases catalytic activity. However, providing the reaction capacity of alloy nanoparticles the surface electronic structure strongly depends on their atomic ordering. Therefore, to theoretically determine catalytic properties, one needs to use a most real structural model complying with Cu-Au nanoparticles under various external influences. So, thermal stability limits were studied for the initial L12 phase in Cu3Au nanoalloy clusters up to 8.0 nm and Cu-Au clusters up to 3.0 nm at various degrees of Au atom concentration, with molecular dynamics method using a modified tight-binding TB-SMA potential. Dual structural transition L12 → FCC and further FCC → Ih is shown to be possible under the thermal factor in Cu3Au and Cu-Au clusters with the diameter up to 3.0 nm. The temperature of the structural transition FCC → Ih is established to decrease for small particles of Cu-Au alloy under the increase of Au atom concentration. For clusters with this structural transition, the melting point is found to be a linear increasing function of concentration, and for clusters without FCC → Ih structural transition, the melting point is a linear decreasing function of Au content. Thus, the article shows that doping Cu nanoclusters with Au atoms allows to control the forming structure as well as the melting point.

  6. A Thermally Stable NiZn/Ta/Ni Scheme to Replace AuBe/Au Contacts in High-Efficiency AlGaInP-Based Light-Emitting Diodes

    NASA Astrophysics Data System (ADS)

    Kim, Dae-Hyun; Park, Jae-Seong; Kang, Daesung; Seong, Tae-Yeon

    2017-08-01

    We developed NiZn/(Ta/)Ni ohmic contacts to replace expensive AuBe/Au contacts commonly used in high-efficiency AlGaInP-based light-emitting diodes (LEDs), and compared the electrical properties of the two contact types. Unlike the AuBe/Au (130 nm/100 nm) contact, the NiZn/Ta/Ni (130 nm/20 nm/100 nm) contact shows improved electrical properties after being annealed at 500°C, with a contact resistivity of 5.2 × 10-6 Ω cm2. LEDs with the NiZn/Ta/Ni contact exhibited a 4.4% higher output power (at 250 mW) than LEDs with the AuBe/Au contact. In contrast to the trend for the AuBe/Au contact, the Ga 2 p core level for the NiZn/Ta/Ni contact shifted toward lower binding energies after being annealed at 500°C. Auger electron spectroscopy (AES) depth profiles showed that annealing the AuBe/Au samples caused the outdiffusion of both Be and P atoms into the metal contact, whereas in the NiZn/Ta/Ni samples, Zn atoms indiffused into the GaP layer. The annealing-induced electrical degradation and ohmic contact formation mechanisms are described and discussed on the basis of the results of x-ray photoemission spectroscopy and AES.

  7. Composition distributions in FePt(Au) nanoparticles

    NASA Astrophysics Data System (ADS)

    Srivastava, C.; Nikles, D. E.; Harrell, J. W.; Thompson, G. B.

    2010-08-01

    Ternary alloy FePt(Au) nanoparticles were prepared by the co-reduction of platinum(II) acetylacetonate and gold(III) acetate and the thermal decomposition of iron pentacarbonyl in hot phenyl ether in the presence of oleic acid and oleylamine ligands. This gave spherical particles with an average diameter of 4.4 nm with a range of diameters from approximately 1.6-9 nm. The as-synthesized particles had a solid solution, face-centered-cubic structure. Though the average composition of the particles was Fe44Pt45Au11, individual particle analysis by Scanning Transmission Electron Microscopy-X-ray Energy Dispersive Spectroscopy showed a broad distribution in composition. In general, smaller-sized particles tended to have a lower amount of Au as compared to larger-sized particles. As the Au content increased, the ratio of Fe/Pt widened.

  8. Ratio of shear viscosity to entropy density in multifragmentation of Au + Au

    NASA Astrophysics Data System (ADS)

    Zhou, C. L.; Ma, Y. G.; Fang, D. Q.; Li, S. X.; Zhang, G. Q.

    2012-06-01

    The ratio of the shear viscosity (η) to entropy density (s) for the intermediate energy heavy-ion collisions has been calculated by using the Green-Kubo method in the framework of the quantum molecular dynamics model. The theoretical curve of η/s as a function of the incident energy for the head-on Au + Au collisions displays that a minimum region of η/s has been approached at higher incident energies, where the minimum η/s value is about 7 times Kovtun-Son-Starinets (KSS) bound (1/4π). We argue that the onset of minimum η/s region at higher incident energies corresponds to the nuclear liquid gas phase transition in nuclear multifragmentation.

  9. Risk Assessment References: Documented Literature Search

    DTIC Science & Technology

    2012-10-01

    the Minister of National Defence, 2012 © Sa Majesté la Reine (en droit du Canada), telle que représentée par le ministre de la Défense nationale...vise à démontrer la valeur de l’approche scientifique pour améliorer les capacités de gestion des situations d’urgence en se concentrant sur...l’évaluation des risques et les infrastructures essentielles. Au cours de la première phase du projet, RDDC a effectué une analyse documentaire

  10. Specialists Meeting on Helicopter Design Mission Load Spectra

    DTIC Science & Technology

    1976-08-01

    partement Scientifique AEROSPATIAI*E - B.P n0 13 13 722 -AINN 1I INTRODUCTION Si 1e princips g~ndral de d~tarmination des dur~ea de vie des pibcea d’h...reprdsentatives de l’utilisation h 6valuer un certain nombro do jauges.extensom~triques. Coa jauges , placgos sur chacun des 4ldmonte critiquos au point do Vuo...sensitivity. 1. INTRODUCTION The design of the fatigue critical components of a helicopter, which are mainly the blades, the hub, and the drive system

  11. Surface effects on the radiation response of nanoporous Au foams

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Fu, E. G.; Caro, M.; Wang, Y. Q.

    2012-11-05

    We report on an experimental and simulation campaign aimed at exploring the radiation response of nanoporous Au (np-Au) foams. We find different defect accumulation behavior by varying radiation dose-rate in ion-irradiated np-Au foams. Stacking fault tetrahedra are formed when np-Au foams are irradiated at high dose-rate, but they do not seem to be formed in np-Au at low dose-rate irradiation. A model is proposed to explain the dose-rate dependent defect accumulation based on these results.

  12. Simultaneous AuIII Extraction and In Situ Formation of Polymeric Membrane-Supported Au Nanoparticles: A Sustainable Process with Application in Catalysis.

    PubMed

    Mora-Tamez, Lucía; Esquivel-Peña, Vicente; Ocampo, Ana L; Rodríguez de San Miguel, Eduardo; Grande, Daniel; de Gyves, Josefina

    2017-04-10

    A polymeric membrane-supported catalyst with immobilized gold nanoparticles (AuNPs) was prepared through the extraction and in situ reduction of Au III salts in a one-step strategy. Polymeric inclusion membranes (PIMs) and polymeric nanoporous membranes (PNMs) were tested as different membrane-support systems. Transport experiments indicated that PIMs composed of cellulose triacetate, 2-nitrophenyloctyl ether, and an aliphatic tertiary amine (Adogen 364 or Alamine 336) were the most efficient supports for Au III extraction. The simultaneous extraction and reduction processes were proven to be the result of a synergic phenomenon in which all the membrane components were involved. Scanning electron microscopy characterization of cross-sectional samples suggested a distribution of AuNPs throughout the membrane. Transmission electron microscopy characterization of the AuNPs indicated average particle sizes of 36.7 and 2.9 nm for the PIMs and PNMs, respectively. AuNPs supported on PIMs allowed for >95.4 % reduction of a 0.05 mmol L -1 4-nitrophenol aqueous solution with 10 mmol L -1 NaBH 4 solution within 25 min. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. The diagnostic and clinical significance of café-au-lait macules.

    PubMed

    Shah, Kara N

    2010-10-01

    Café-au-lait, also referred to as café-au-lait spots or café-au-lait macules, present as well-circumscribed, evenly pigmented macules and patches that range in size from 1 to 2 mm to greater than 20 cm in greatest diameter. Café-au-lait are common in children. Although most café-au-lait present as 1 or 2 spots in an otherwise healthy child, the presence of multiple café-au-lait, large segmental café-au-lait, associated facial dysmorphism, other cutaneous anomalies, or unusual findings on physical examination should suggest the possibility of an associated syndrome. While neurofibromatosis type 1 is the most common syndrome seen in children with multiple café-au-lait, other syndromes associated with one or more café-au-lait include McCune-Albright syndrome, Legius syndrome, Noonan syndrome and other neuro-cardio-facialcutaneous syndromes, ring chromosome syndromes, and constitutional mismatch repair deficiency syndrome. Copyright © 2010 Elsevier Inc. All rights reserved.

  14. Noncentrosymmetric superconductor BeAu

    NASA Astrophysics Data System (ADS)

    Amon, A.; Svanidze, E.; Cardoso-Gil, R.; Wilson, M. N.; Rosner, H.; Bobnar, M.; Schnelle, W.; Lynn, J. W.; Gumeniuk, R.; Hennig, C.; Luke, G. M.; Borrmann, H.; Leithe-Jasper, A.; Grin, Yu.

    2018-01-01

    Mixed spin-singlet and spin-triplet pairing can occur in noncentrosymmetric superconductors. In this respect, a comprehensive characterization of the noncentrosymmetric superconductor BeAu was carried out. It was established that BeAu undergoes a structural phase transition from a low-temperature noncentrosymmetric FeSi structure type to a high-temperature centrosymmetric structure in the CsCl type at Ts=860 K. The low-temperature modification exhibits a superconducting transition below Tc=3.3 K. The values of lower (Hc1=32 Oe) and upper (Hc2=335 Oe) critical fields are rather small, confirming that this type-II (κG-L=2.3 ) weakly coupled (λe-p=0.5 ,Δ Ce/γnTc≈1.26 ) superconductor can be well understood within the Bardeen-Cooper-Schrieffer theory. The muon spin relaxation analysis indicates that the time-reversal symmetry is preserved when the superconducting state is entered, supporting conventional superconductivity in BeAu. From the density functional band structure calculations, a considerable contribution of the Be electrons to the superconducting state was established. On average, a rather small mass renormalization was found, consistent with the experimental data.

  15. Au/NiFe/M(Au, MoS2, graphene) trilayer magnetoplasmonics DNA-hybridized sensors with high record of sensitivity.

    PubMed

    Faridi, Ehsan; Moradi, Maryam; Ansari, Narges; Baradaran Ghasemi, Amir Hossein; Afshar, Amir; Mohseni Armaki, Seyed Majid

    2017-12-01

    The demonstration of biosensors based on the surface plasmon effect holds promise for future high-sensitive electrodeless biodetection. The combination of magnetic effects with surface plasmon waves brings additional freedom to improve sensitivity and signal selectivity. Stacking biosensors with two-dimensional (2-D) materials, e.g., graphene (Gr) and MoS2, can influence plasmon waves and facilitate surface physiochemical properties as additional versatility aspects. We demonstrate magnetoplasmonic biosensors through the detuning of surface plasmon oscillation modes affected by magnetic effect via the presence of the NiFe (Py) layer and different light absorbers of Gr, MoS2, and Au ultrathin layers in three stacks of Au/Py/M(MoS2, Gr, Au) trilayers. We found minimum reflection, resonance angle shift, and transverse magneto-optical Kerr effect (TMOKE) responses of all sensors in the presence of the ss-DNA monolayer. Very few changes of ∼5×10-7 in the ss-DNA's refractive index result in valuable TMOKE response. We found that the presence of three-layer Gr and two-layer MoS2 on top of the Au/Py bilayer can dramatically increase the sensitivity by nine and four times, respectively, than the conventional Au/Co/Au trilayer. Our results show the highest reported DNA sensitivity based on the coupling of light with 2-D materials in magnetoplasmonic devices. (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

  16. Partonic Flow and phi-Meson production in Au+Au collisions at sqrt radical sNN = 200 GeV.

    PubMed

    Abelev, B I; Aggarwal, M M; Ahammed, Z; Anderson, B D; Arkhipkin, D; Averichev, G S; Bai, Y; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Baumgart, S; Belaga, V V; Bellingeri-Laurikainen, A; Bellwied, R; Benedosso, F; Betts, R R; Bhardwaj, S; Bhasin, A; Bhati, A K; Bichsel, H; Bielcik, J; Bielcikova, J; Bland, L C; Blyth, S-L; Bombara, M; Bonner, B E; Botje, M; Bouchet, J; Brandin, A V; Bravar, A; Burton, T P; Bystersky, M; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca Sánchez, M; Callner, J; Catu, O; Cebra, D; Chajecki, Z; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, J H; Chen, J Y; Cheng, J; Cherney, M; Chikanian, A; Christie, W; Chung, S U; Coffin, J P; Cormier, T M; Cosentino, M R; Cramer, J G; Crawford, H J; Das, D; Dash, S; Daugherity, M; de Moura, M M; Dedovich, T G; DePhillips, M; Derevschikov, A A; Didenko, L; Dietel, T; Djawotho, P; Dogra, S M; Dong, X; Drachenberg, J L; Draper, J E; Du, F; Dunin, V B; Dunlop, J C; Dutta Mazumdar, M R; Eckardt, V; Edwards, W R; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Estienne, M; Fachini, P; Fatemi, R; Fedorisin, J; Feng, A; Filip, P; Finch, E; Fine, V; Fisyak, Y; Fu, J; Gagliardi, C A; Gaillard, L; Ganti, M S; Garcia-Solis, E; Ghazikhanian, V; Ghosh, P; Gorbunov, Y G; Gos, H; Grebenyuk, O; Grosnick, D; Grube, B; Guertin, S M; Guimaraes, K S F F; Gupta, N; Haag, B; Hallman, T J; Hamed, A; Harris, J W; He, W; Heinz, M; Henry, T W; Heppelmann, S; Hippolyte, B; Hirsch, A; Hjort, E; Hoffman, A M; Hoffmann, G W; Hofman, D J; Hollis, R S; Horner, M J; Huang, H Z; Hughes, E W; Humanic, T J; Igo, G; Iordanova, A; Jacobs, P; Jacobs, W W; Jakl, P; Jia, F; Jones, P G; Judd, E G; Kabana, S; Kang, K; Kapitan, J; Kaplan, M; Keane, D; Kechechyan, A; Kettler, D; Khodyrev, V Yu; Kim, B C; Kiryluk, J; Kisiel, A; Kislov, E M; Klein, S R; Knospe, A G; Kocoloski, A; Koetke, D D; Kollegger, T; Kopytine, M; Kotchenda, L; Kouchpil, V; Kowalik, K L; Kravtsov, P; Kravtsov, V I; Krueger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kurnadi, P; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; LaPointe, S; Laue, F; Lauret, J; Lebedev, A; Lednicky, R; Lee, C-H; Lehocka, S; LeVine, M J; Li, C; Li, Q; Li, Y; Lin, G; Lin, X; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, H; Liu, J; Liu, L; Ljubicic, T; Llope, W J; Longacre, R S; Love, W A; Lu, Y; Ludlam, T; Lynn, D; Ma, G L; Ma, J G; Ma, Y G; Mahapatra, D P; Majka, R; Mangotra, L K; Manweiler, R; Margetis, S; Markert, C; Martin, L; Matis, H S; Matulenko, Yu A; McClain, C J; McShane, T S; Melnick, Yu; Meschanin, A; Millane, J; Miller, M L; Minaev, N G; Mioduszewski, S; Mironov, C; Mischke, A; Mitchell, J; Mohanty, B; Morozov, D A; Munhoz, M G; Nandi, B K; Nattrass, C; Nayak, T K; Nelson, J M; Nepali, C; Netrakanti, P K; Nogach, L V; Nurushev, S B; Odyniec, G; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Pachr, M; Pal, S K; Panebratsev, Y; Pavlinov, A I; Pawlak, T; Peitzmann, T; Perevoztchikov, V; Perkins, C; Peryt, W; Phatak, S C; Planinic, M; Pluta, J; Poljak, N; Porile, N; Poskanzer, A M; Potekhin, M; Potrebenikova, E; Potukuchi, B V K S; Prindle, D; Pruneau, C; Putschke, J; Qattan, I A; Raniwala, R; Raniwala, S; Ray, R L; Relyea, D; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Rose, A; Roy, C; Ruan, L; Russcher, M J; Sahoo, R; Sakrejda, I; Sakuma, T; Salur, S; Sandweiss, J; Sarsour, M; Sazhin, P S; Schambach, J; Scharenberg, R P; Schmitz, N; Seger, J; Selyuzhenkov, I; Seyboth, P; Shabetai, A; Shahaliev, E; Shao, M; Sharma, M; Shen, W Q; Shimanskiy, S S; Sichtermann, E P; Simon, F; Singaraju, R N; Smirnov, N; Snellings, R; Sorensen, P; Sowinski, J; Speltz, J; Spinka, H M; Srivastava, B; Stadnik, A; Stanislaus, T D S; Staszak, D; Stock, R; Strikhanov, M; Stringfellow, B; Suaide, A A P; Suarez, M C; Subba, N L; Sumbera, M; Sun, X M; Sun, Z; Surrow, B; Symons, T J M; Szanto de Toledo, A; Takahashi, J; Tang, A H; Tarnowsky, T; Thomas, J H; Timmins, A R; Timoshenko, S; Tokarev, M; Trainor, T A; Trentalange, S; Tribble, R E; Tsai, O D; Ulery, J; Ullrich, T; Underwood, D G; Van Buren, G; van der Kolk, N; van Leeuwen, M; Vander Molen, A M; Varma, R; Vasilevski, I M; Vasiliev, A N; Vernet, R; Vigdor, S E; Viyogi, Y P; Vokal, S; Voloshin, S A; Waggoner, W T; Wang, F; Wang, G; Wang, J S; Wang, X L; Wang, Y; Watson, J W; Webb, J C; Westfall, G D; Wetzler, A; Whitten, C; Wieman, H; Wissink, S W; Witt, R; Wu, J; Wu, Y; Xu, N; Xu, Q H; Xu, Z; Yepes, P; Yoo, I-K; Yue, Q; Yurevich, V I; Zhan, W; Zhang, H; Zhang, W M; Zhang, Y; Zhang, Z P; Zhao, Y; Zhong, C; Zhou, J; Zoulkarneev, R; Zoulkarneeva, Y; Zubarev, A N; Zuo, J X

    2007-09-14

    We present first measurements of the phi-meson elliptic flow (v2(pT)) and high-statistics pT distributions for different centralities from radical sNN=200 GeV Au+Au collisions at RHIC. In minimum bias collisions the v2 of the phi meson is consistent with the trend observed for mesons. The ratio of the yields of the Omega to those of the phi as a function of transverse momentum is consistent with a model based on the recombination of thermal s quarks up to pT approximately 4 GeV/c, but disagrees at higher momenta. The nuclear modification factor (R CP) of phi follows the trend observed in the K S 0 mesons rather than in Lambda baryons, supporting baryon-meson scaling. These data are consistent with phi mesons in central Au+Au collisions being created via coalescence of thermalized s quarks and the formation of a hot and dense matter with partonic collectivity at RHIC.

  17. ΛΛ correlation function in Au + Au collisions at √ sNN = 200 GeV

    DOE PAGES

    Adamczyk, L.

    2015-01-12

    In this study, we present ΛΛ correlation measurements in heavy-ion collisions for Au+Au collisions at √ sNN = 200 GeV using the STAR experiment at the Relativistic Heavy-Ion Collider (RHIC). The Lednický-Lyuboshitz analytical model has been used to fit the data to obtain a source size, a scattering length and an effective range. Implications of the measurement of the ΛΛ correlation function and interaction parameters for di-hyperon searches are discussed.

  18. Facile preparation of SERS and catalytically active Au nanostructures using furfuryl derivatives

    NASA Astrophysics Data System (ADS)

    Kim, Ki-Jung; Kim, Hyun-Chul; Park, Minsun; Huh, Seong

    2017-08-01

    Six different types of Au nanostructures with rough surfaces were readily prepared through the redox reactions between Au precursor, AuCl4-, and furfuryl derivatives without extra metal surface capping ligands, in deionized water at room temperature. Furfuryl alcohol (FA) or furfurylamine (FFA) was used as a sole reducing agent for the reduction of Au precursor. Both FA and FFA effectively polymerized during the redox reactions to form polyfuran polymers. These polymers are thought to act as surface capping ligands during the formation of Au nanostructures. Experiments were conducted with three different concentrations of each furfuryl derivative. Interestingly, Au particles prepared from the reaction with varying concentration of FA or FFA showed large differences in size, and revealed that the higher the ratios of [FA]/[AuCl4-] or [FFA]/[AuCl4-], the smaller the size of Au particles. The size of Au particles was in the range of 1 μm to under 30 nm. Among these samples, two nanostructured Au particles, AuFA-4 and AuFFA-1, deposited on a Si wafer by a simple drop-casting method, were revealed as highly active surface-enhanced Raman scattering (SERS) substrates for the detection of methylene blue (MB) and crystal violet (CV). High SERS enhancement factors (EFs) of 106 ∼ 108 for MB and CV were observed. Small size Au nanoparticles (AuFFA-2 and AuFFA-4) were also found to be very active for the catalytic hydrogenation of 4-nitrophenol to 4-aminophenol in the presence of NaBH4 at room temperature. AuFFA-2 could be recycled eight times, without losing its activity.

  19. Elliptic Flow in Au+Au Collisions at √sNN = 130 GeV

    NASA Astrophysics Data System (ADS)

    Ackermann, K. H.; Adams, N.; Adler, C.; Ahammed, Z.; Ahmad, S.; Allgower, C.; Amsbaugh, J.; Anderson, M.; Anderssen, E.; Arnesen, H.; Arnold, L.; Averichev, G. S.; Baldwin, A.; Balewski, J.; Barannikova, O.; Barnby, L. S.; Baudot, J.; Beddo, M.; Bekele, S.; Belaga, V. V.; Bellwied, R.; Bennett, S.; Bercovitz, J.; Berger, J.; Betts, W.; Bichsel, H.; Bieser, F.; Bland, L. C.; Bloomer, M.; Blyth, C. O.; Boehm, J.; Bonner, B. E.; Bonnet, D.; Bossingham, R.; Botlo, M.; Boucham, A.; Bouillo, N.; Bouvier, S.; Bradley, K.; Brady, F. P.; Braithwaite, E. S.; Braithwaite, W.; Brandin, A.; Brown, R. L.; Brugalette, G.; Byrd, C.; Caines, H.; Calderón de La Barca Sánchez, M.; Cardenas, A.; Carr, L.; Carroll, J.; Castillo, J.; Caylor, B.; Cebra, D.; Chatopadhyay, S.; Chen, M. L.; Chen, W.; Chen, Y.; Chernenko, S. P.; Cherney, M.; Chikanian, A.; Choi, B.; Chrin, J.; Christie, W.; Coffin, J. P.; Conin, L.; Consiglio, C.; Cormier, T. M.; Cramer, J. G.; Crawford, H. J.; Danilov, V. I.; Dayton, D.; Demello, M.; Deng, W. S.; Derevschikov, A. A.; Dialinas, M.; Diaz, H.; Deyoung, P. A.; Didenko, L.; Dimassimo, D.; Dioguardi, J.; Dominik, W.; Drancourt, C.; Draper, J. E.; Dunin, V. B.; Dunlop, J. C.; Eckardt, V.; Edwards, W. R.; Efimov, L. G.; Eggert, T.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Etkin, A.; Fachini, P.; Feliciano, C.; Ferenc, D.; Ferguson, M. I.; Fessler, H.; Finch, E.; Fine, V.; Fisyak, Y.; Flierl, D.; Flores, I.; Foley, K. J.; Fritz, D.; Gagunashvili, N.; Gans, J.; Gazdzicki, M.; Germain, M.; Geurts, F.; Ghazikhanian, V.; Gojak, C.; Grabski, J.; Grachov, O.; Grau, M.; Greiner, D.; Greiner, L.; Grigoriev, V.; Grosnick, D.; Gross, J.; Guilloux, G.; Gushin, E.; Hall, J.; Hallman, T. J.; Hardtke, D.; Harper, G.; Harris, J. W.; He, P.; Heffner, M.; Heppelmann, S.; Herston, T.; Hill, D.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffmann, G. W.; Horsley, M.; Howe, M.; Huang, H. Z.; Humanic, T. J.; Hümmler, H.; Hunt, W.; Hunter, J.; Igo, G. J.; Ishihara, A.; Ivanshin, Yu. I.; Jacobs, P.; Jacobs, W. W.; Jacobson, S.; Jared, R.; Jensen, P.; Johnson, I.; Jones, P. G.; Judd, E.; Kaneta, M.; Kaplan, M.; Keane, D.; Kenney, V. P.; Khodinov, A.; Klay, J.; Klein, S. R.; Klyachko, A.; Koehler, G.; Konstantinov, A. S.; Kormilitsyne, V.; Kotchenda, L.; Kotov, I.; Kovalenko, A. D.; Kramer, M.; Kravtsov, P.; Krueger, K.; Krupien, T.; Kuczewski, P.; Kuhn, C.; Kunde, G. J.; Kunz, C. L.; Kutuev, R. Kh.; Kuznetsov, A. A.; Lakehal-Ayat, L.; Lamas-Valverde, J.; Lamont, M. A.; Landgraf, J. M.; Lange, S.; Lansdell, C. P.; Lasiuk, B.; Laue, F.; Lebedev, A.; Lecompte, T.; Leonhardt, W. J.; Leontiev, V. M.; Leszczynski, P.; Levine, M. J.; Li, Q.; Li, Q.; Li, Z.; Liaw, C.-J.; Lin, J.; Lindenbaum, S. J.; Lindenstruth, V.; Lindstrom, P. J.; Lisa, M. A.; Liu, H.; Ljubicic, T.; Llope, W. J.; Locurto, G.; Long, H.; Longacre, R. S.; Lopez-Noriega, M.; Lopiano, D.; Love, W. A.; Lutz, J. R.; Lynn, D.; Madansky, L.; Maier, R.; Majka, R.; Maliszewski, A.; Margetis, S.; Marks, K.; Marstaller, R.; Martin, L.; Marx, J.; Matis, H. S.; Matulenko, Yu. A.; Matyushevski, E. A.; McParland, C.; McShane, T. S.; Meier, J.; Melnick, Yu.; Meschanin, A.; Middlekamp, P.; Mikhalin, N.; Miller, B.; Milosevich, Z.; Minaev, N. G.; Minor, B.; Mitchell, J.; Mogavero, E.; Moiseenko, V. A.; Moltz, D.; Moore, C. F.; Morozov, V.; Morse, R.; de Moura, M. M.; Munhoz, M. G.; Mutchler, G. S.; Nelson, J. M.; Nevski, P.; Ngo, T.; Nguyen, M.; Nguyen, T.; Nikitin, V. A.; Nogach, L. V.; Noggle, T.; Norman, B.; Nurushev, S. B.; Nussbaum, T.; Nystrand, J.; Odyniec, G.; Ogawa, A.; Ogilvie, C. A.; Olchanski, K.; Oldenburg, M.; Olson, D.; Ososkov, G. A.; Ott, G.; Padrazo, D.; Paic, G.; Pandey, S. U.; Panebratsev, Y.; Panitkin, S. Y.; Pavlinov, A. I.; Pawlak, T.; Pentia, M.; Perevotchikov, V.; Peryt, W.; Petrov, V. A.; Pinganaud, W.; Pirogov, S.; Platner, E.; Pluta, J.; Polk, I.; Porile, N.; Porter, J.; Poskanzer, A. M.; Potrebenikova, E.; Prindle, D.; Pruneau, C.; Puskar-Pasewicz, J.; Rai, G.; Rasson, J.; Ravel, O.; Ray, R. L.; Razin, S. V.; Reichhold, D.; Reid, J.; Renfordt, R. E.; Retiere, F.; Ridiger, A.; Riso, J.; Ritter, H. G.; Roberts, J. B.; Roehrich, D.; Rogachevski, O. V.; Romero, J. L.; Roy, C.; Russ, D.; Rykov, V.; Sakrejda, I.; Sanchez, R.; Sandler, Z.; Sandweiss, J.; Sappenfield, P.; Saulys, A. C.; Savin, I.; Schambach, J.; Scharenberg, R. P.; Scheblien, J.; Scheetz, R.; Schlueter, R.; Schmitz, N.; Schroeder, L. S.; Schulz, M.; Schüttauf, A.; Sedlmeir, J.; Seger, J.; Seliverstov, D.; Seyboth, J.; Seyboth, P.; Seymour, R.; Shakaliev, E. I.; Shestermanov, K. E.; Shi, Y.; Shimanskii, S. S.; Shuman, D.; Shvetcov, V. S.; Skoro, G.; Smirnov, N.; Smykov, L. P.; Snellings, R.; Solberg, K.; Sowinski, J.; Spinka, H. M.; Srivastava, B.; Stephenson, E. J.; Stock, R.; Stolpovsky, A.; Stone, N.; Stone, R.; Strikhanov, M.; Stringfellow, B.; Stroebele, H.; Struck, C.; Suaide, A. A.; Sugarbaker, E.; Suire, C.; Symons, T. J.; Takahashi, J.; Tang, A. H.; Tarchini, A.; Tarzian, J.; Thomas, J. H.; Tikhomirov, V.; Szanto de Toledo, A.; Tonse, S.; Trainor, T.; Trentalange, S.; Tokarev, M.; Tonjes, M. B.; Trofimov, V.; Tsai, O.; Turner, K.; Ullrich, T.; Underwood, D. G.; Vakula, I.; van Buren, G.; Vandermolen, A. M.; Vanyashin, A.; Vasilevski, I. M.; Vasiliev, A. N.; Vigdor, S. E.; Visser, G.; Voloshin, S. A.; Vu, C.; Wang, F.; Ward, H.; Weerasundara, D.; Weidenbach, R.; Wells, R.; Wells, R.; Wenaus, T.; Westfall, G. D.; Whitfield, J. P.; Whitten, C.; Wieman, H.; Willson, R.; Wilson, K.; Wirth, J.; Wisdom, J.; Wissink, S. W.; Witt, R.; Wolf, J.; Wood, L.; Xu, N.; Xu, Z.; Yakutin, A. E.; Yamamoto, E.; Yang, J.; Yepes, P.; Yokosawa, A.; Yurevich, V. I.; Zanevski, Y. V.; Zhang, J.; Zhang, W. M.; Zhu, J.; Zimmerman, D.; Zoulkarneev, R.; Zubarev, A. N.

    2001-01-01

    Elliptic flow from nuclear collisions is a hadronic observable sensitive to the early stages of system evolution. We report first results on elliptic flow of charged particles at midrapidity in Au+Au collisions at sNN = 130 GeV using the STAR Time Projection Chamber at the Relativistic Heavy Ion Collider. The elliptic flow signal, v2, averaged over transverse momentum, reaches values of about 6% for relatively peripheral collisions and decreases for the more central collisions. This can be interpreted as the observation of a higher degree of thermalization than at lower collision energies. Pseudorapidity and transverse momentum dependence of elliptic flow are also presented.

  20. Le transfert de connaissances entre les mathematiques et les sciences. Une etude exploratoire aupres d'eleves de 4e secondaire

    NASA Astrophysics Data System (ADS)

    Samson, Ghislain

    2003-06-01

    Au moment ou dans plusieurs pays on travaille a refondre les programmes d'etudes, tant au primaire qu'au secondaire, l'interet pour le transfert renait. Un des concepts fondamentaux en apprentissage consiste en l'habilete a reutiliser de facon consciente et efficace un acquis d'une situation a une autre situation. Cette recherche emane de preoccupations professionnelles au moment ou le chercheur etait enseignant au secondaire. Au cours de ces annees, il lui a ete possible de constater que plusieurs eleves percevaient difficilement les liens presents entre les disciplines mathematiques et scientifiques. Des travaux en psychologie cognitive et plus particulierement selon une perspective du traitement de l'information ont servi de cadre de reference pour evaluer et analyser les capacites de transfert aupres d'eleves de 4e secondaire. Ce cadre de reference permet de formuler le principal objectif qui est de mieux comprendre le processus de transfert chez des eleves en situation de resolution de problemes scientifiques. Cette these s'interesse donc au transfert en tant que phenomene important du processus d'apprentissage au sens de l'integration. La methode de recherche choisie, de nature qualitative, est principalement axee sur l'evaluation de la capacite a transferer des connaissances lors d'une epreuve et d'un entretien. Pour evaluer ce potentiel de transfert, nous avons elabore deux outils: une epreuve en mathematiques et en sciences et un guide d'entretien. Pour la passation de l'epreuve, le chercheur a pu compter sur la collaboration de 130 sujets provenant de deux ecoles. L'entretien complete la prise de donnees avec 13 sujets ayant accepte de poursuivre l'etude. Les donnees recueillies par ces instruments font ensuite l'objet d'une analyse de contenu. En premier lieu, les verbatims de l'epreuve et de l'entretien ont ete transcrits, puis codifies. La correction des reponses fournies pour les problemes resolus s'est faite a partir d'une grille d

  1. Structural and morphological peculiarities of hybrid Au/nanodiamond engineered nanostructures

    NASA Astrophysics Data System (ADS)

    Matassa, Roberto; Orlanducci, Silvia; Reina, Giacomo; Cassani, Maria Cristina; Passeri, Daniele; Terranova, Maria Letizia; Rossi, Marco

    2016-08-01

    Nanostructured Au nano-platelets have been synthesized from an Au(III) complex by growth process triggered by nanodiamond (ND). An electroless synthetic route has been used to obtain 2D Au/ND architectures, where individual nanodiamond particles are intimately embedded into face-centered cubic Au platelets. The combined use of high resolution transmission electron microscopy (HR-TEM) and selected area electron diffraction (SAED), was able to reveal the unusual organization of these hybrid nanoparticles, ascertaining the existence of preferential crystallographic orientations for both nanocrystalline species and highlighting their mutual locations. Detailed information on the sample microstructure have been gathered by fast Fourier transform (FFT) and inverse fast Fourier transform (IFFT) of HR-TEM images, allowing us to figure out the role of Au defects, able to anchor ND crystallites and to provide specific sites for heteroepitaxial Au growth. Aggregates constituted by coupled ND and Au, represent interesting systems conjugating the best optoelectronics and plasmonics properties of the two different materials. In order to promote realistically the applications of such outstanding Au/ND materials, the cooperative mechanisms at the basis of material synthesis and their influence on the details of the hybrid nanostructures have to be deeply understood.

  2. Structural and morphological peculiarities of hybrid Au/nanodiamond engineered nanostructures

    PubMed Central

    Matassa, Roberto; Orlanducci, Silvia; Reina, Giacomo; Cassani, Maria Cristina; Passeri, Daniele; Terranova, Maria Letizia; Rossi, Marco

    2016-01-01

    Nanostructured Au nano-platelets have been synthesized from an Au(III) complex by growth process triggered by nanodiamond (ND). An electroless synthetic route has been used to obtain 2D Au/ND architectures, where individual nanodiamond particles are intimately embedded into face-centered cubic Au platelets. The combined use of high resolution transmission electron microscopy (HR-TEM) and selected area electron diffraction (SAED), was able to reveal the unusual organization of these hybrid nanoparticles, ascertaining the existence of preferential crystallographic orientations for both nanocrystalline species and highlighting their mutual locations. Detailed information on the sample microstructure have been gathered by fast Fourier transform (FFT) and inverse fast Fourier transform (IFFT) of HR-TEM images, allowing us to figure out the role of Au defects, able to anchor ND crystallites and to provide specific sites for heteroepitaxial Au growth. Aggregates constituted by coupled ND and Au, represent interesting systems conjugating the best optoelectronics and plasmonics properties of the two different materials. In order to promote realistically the applications of such outstanding Au/ND materials, the cooperative mechanisms at the basis of material synthesis and their influence on the details of the hybrid nanostructures have to be deeply understood. PMID:27514638

  3. Rho0 production and possible modification in Au+Au and p+p collisions at square root [sNN] = 200 GeV.

    PubMed

    Adams, J; Adler, C; Aggarwal, M M; Ahammed, Z; Amonett, J; Anderson, B D; Arkhipkin, D; Averichev, G S; Badyal, S K; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellwied, R; Berger, J; Bezverkhny, B I; Bhardwaj, S; Bhati, A K; Bichsel, H; Billmeier, A; Bland, L C; Blyth, C O; Bonner, B E; Botje, M; Boucham, A; Brandin, A; Bravar, A; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca Sánchez, M; Carroll, J; Castillo, J; Cebra, D; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, Y; Chernenko, S P; Cherney, M; Chikanian, A; Christie, W; Coffin, J P; Cormier, T M; Cramer, J G; Crawford, H J; Das, D; Das, S; Derevschikov, A A; Didenko, L; Dietel, T; Dong, W J; Dong, X; Draper, J E; Du, F; Dubey, A K; Dunin, V B; Dunlop, J C; Dutta Majumdar, M R; Eckardt, V; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Estienne, M; Fachini, P; Faine, V; Faivre, J; Fatemi, R; Filimonov, K; Filip, P; Finch, E; Fisyak, Y; Flierl, D; Foley, K J; Fu, J; Gagliardi, C A; Gagunashvili, N; Gans, J; Ganti, M S; Gaudichet, L; Geurts, F; Ghazikhanian, V; Ghosh, P; Gonzalez, J E; Grachov, O; Grebenyuk, O; Gronstal, S; Grosnick, D; Guertin, S M; Gupta, A; Gutierrez, T D; Hallman, T J; Hamed, A; Hardtke, D; Harris, J W; Heinz, M; Henry, T W; Heppelmann, S; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horsley, M; Huang, H Z; Huang, S L; Hughes, E; Humanic, T J; Igo, G; Ishihara, A; Jacobs, P; Jacobs, W W; Janik, M; Jiang, H; Johnson, I; Jones, P G; Judd, E G; Kabana, S; Kaplan, M; Keane, D; Khodyrev, V Yu; Kiryluk, J; Kisiel, A; Klay, J; Klein, S R; Klyachko, A; Koetke, D D; Kollegger, T; Kopytine, M; Kotchenda, L; Kovalenko, A D; Kramer, M; Kravtsov, P; Kravtsov, V I; Krueger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kunde, G J; Kunz, C L; Kutuev, R Kh; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; Lasiuk, B; Laue, F; Lauret, J; Lebedev, A; Lednický, R; LeVine, M J; Li, C; Li, Q; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, L; Liu, Z; Liu, Q J; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; Lopez-Noriega, M; Love, W A; Ludlam, T; Lynn, D; Ma, J; Ma, Y G; Magestro, D; Mahajan, S; Mangotra, L K; Mahapatra, D P; Majka, R; Manweiler, R; Margetis, S; Markert, C; Martin, L; Marx, J; Matis, H S; Matulenko, Yu A; McClain, C J; McShane, T S; Meissner, F; Melnick, Yu; Meschanin, A; Miller, M L; Milosevich, Z; Minaev, N G; Mironov, C; Mischke, A; Mishra, D; Mitchell, J; Mohanty, B; Molnar, L; Moore, C F; Mora-Corral, M J; Morozov, D A; Morozov, V; De Moura, M M; Munhoz, M G; Nandi, B K; Nayak, S K; Nayak, T K; Nelson, J M; Netrakanti, P K; Nikitin, V A; Nogach, L V; Norman, B; Nurushev, S B; Odyniec, G; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Paic, G; Pal, S K; Panebratsev, Y; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Peitzmann, T; Perevoztchikov, V; Perkins, C; Peryt, W; Petrov, V A; Phatak, S C; Picha, R; Planinic, M; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M; Potrebenikova, E; Potukuchi, B V K S; Prindle, D; Pruneau, C; Putschke, J; Rai, G; Rakness, G; Raniwala, R; Raniwala, S; Ravel, O; Ray, R L; Razin, S V; Reichhold, D; Reid, J G; Renault, G; Retiere, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Ruan, L J; Sahoo, R; Sakrejda, I; Salur, S; Sandweiss, J; Savin, I; Schambach, J; Scharenberg, R P; Schmitz, N; Schroeder, L S; Schweda, K; Seger, J; Seyboth, P; Shahaliev, E; Shao, M; Shao, W; Sharma, M; Shestermanov, K E; Shimanskii, S S; Singaraju, R N; Simon, F; Skoro, G; Smirnov, N; Snellings, R; Sood, G; Sorensen, P; Sowinski, J; Speltz, J; Spinka, H M; Srivastava, B; Stanislaus, T D S; Stock, R; Stolpovsky, A; Strikhanov, M; Stringfellow, B; Struck, C; Suaide, A A P; Sugarbaker, E; Suire, C; Sumbera, M; Surrow, B; Symons, T J M; Szanto de Toledo, A; Szarwas, P; Tai, A; Takahashi, J; Tang, A H; Thein, D; Thomas, J H; Timoshenko, S; Tokarev, M; Tonjes, M B; Trainor, T A; Trentalange, S; Tribble, R E; Tsai, O; Ullrich, T; Underwood, D G; Van Buren, G; VanderMolen, A M; Varma, R; Vasilevski, I; Vasiliev, A N; Vernet, R; Vigdor, S E; Viyogi, Y P; Voloshin, S A; Vznuzdaev, M; Waggoner, W; Wang, F; Wang, G; Wang, G; Wang, X L; Wang, Y; Wang, Z M; Ward, H; Watson, J W; Webb, J C; Wells, R; Westfall, G D; Whitten, C; Wieman, H; Willson, R; Wissink, S W; Witt, R; Wood, J; Wu, J; Xu, N; Xu, Z; Xu, Z Z; Yamamoto, E; Yepes, P; Yurevich, V I; Yuting, B; Zanevski, Y V; Zhang, H; Zhang, W M; Zhang, Z P; Zhaomin, Z P; Zizong, Z P; Zołnierczuk, P A; Zoulkarneev, R; Zoulkarneeva, J; Zubarev, A N

    2004-03-05

    We report results on rho(770)(0)-->pi(+)pi(-) production at midrapidity in p+p and peripheral Au+Au collisions at sqrt[s(NN)]=200 GeV. This is the first direct measurement of rho(770)(0)-->pi(+)pi(-) in heavy-ion collisions. The measured rho(0) peak in the invariant mass distribution is shifted by approximately 40 MeV/c(2) in minimum bias p+p interactions and approximately 70 MeV/c(2) in peripheral Au+Au collisions. The rho(0) mass shift is dependent on transverse momentum and multiplicity. The modification of the rho(0) meson mass, width, and shape due to phase space and dynamical effects are discussed.

  4. Au-assisted fabrication of nano-holes on c-plane sapphire via thermal treatment guided by Au nanoparticles as catalysts

    NASA Astrophysics Data System (ADS)

    Sui, Mao; Pandey, Puran; Li, Ming-Yu; Zhang, Quanzhen; Kunwar, Sundar; Lee, Jihoon

    2017-01-01

    Nanoscale patterning of sapphires is a challenging task due to the high mechanical strength, chemical stability as well as thermal durability. In this paper, we demonstrate a gold droplet assisted approach of nano-hole fabrication on c-plane sapphire via a thermal treatment. Uniformly distributed nano-holes are fabricated on the sapphire surface guided by dome shaped Au nanoparticles (NPs) as catalysts and the patterning process is discussed based on the disequilibrium of vapor, liquid, solid interface energies at the Au NP/sapphire interface induced by the Au evaporation at high temperature. Followed by the re-equilibration of interface energy, transport of alumina from the beneath of NPs to the sapphire surface can occur along the NP/sapphire interface resulting in the formation of nano-holes. The fabrication of nano-holes using Au NPs as catalysts is a flexible, economical and convenient approach and can find applications in various optoelectronics.

  5. Au-Ag-Au double shell nanoparticles-based localized surface plasmon resonance and surface-enhanced Raman scattering biosensor for sensitive detection of 2-mercapto-1-methylimidazole.

    PubMed

    Liao, Xue; Chen, Yanhua; Qin, Meihong; Chen, Yang; Yang, Lei; Zhang, Hanqi; Tian, Yuan

    2013-12-15

    In this paper, Au-Ag-Au double shell nanoparticles were prepared based on the reduction of the metal salts HAuCl4 and AgNO3 at the surface of seed particles. Due to the synergistic effect between Au and Ag, the hybrid nanoparticles are particularly stable and show excellent performances on the detection of 2-mercapto-1-methylimidazole (methimazole). The binding of target molecule at the surface of Au-Ag-Au double shell nanoparticles was demonstrated based on both localized surface plasmon resonance (LSPR) and surface-enhanced Raman scattering (SERS) spectra. The LSPR intensity is directly proportional to the methimazole concentration in the range of 0.10-3.00×10(-7) mol L(-1). The SERS spectrum can be applied in identification of methimazole molecule. The LSPR coupled with SERS based on the Au-Ag-Au double shell nanoparticles would be very attractive for the quantitative determination and qualitative analysis of the analytes in medicines. © 2013 Elsevier B.V. All rights reserved.

  6. Stream dynamics between 1 AU and 2 AU: A detailed comparison of observations and theory

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.; Pizzo, V.; Lazarus, A.; Gazis, P. R.

    1984-01-01

    A radial alignment of three solar wind stream structures observed by IMP-7 and -8 (at 1.0 AU) and Voyager 1 and 2 (in the range 1.4 to 1.8 AU) in late 1977 is presented. It is demonstrated that several important aspects of the observed dynamical evolution can be both qualitatively and quantitatively described with a single-fluid 2-D MHD numerical model of quasi-steady corotating flow, including accurate prediction of: (1) the formation of a corotating shock pair at 1.75 AU in the case of a simple, quasi-steady stream; (2) the coalescence of the thermodynamic and magnetic structures associated with the compression regions of two neighboring, interacting, corotating streams; and (3) the dynamical destruction of a small (i.e., low velocity-amplitude, short spatial-scale) stream by its overtaking of a slower moving, high-density region associated with a preceding transient flow. The evolution of these flow systems is discussed in terms of the concepts of filtering and entrainment.

  7. Fluorescent humanized anti-CEA antibody specifically labels metastatic pancreatic cancer in a patient-derived orthotopic xenograft (PDOX) mouse model

    NASA Astrophysics Data System (ADS)

    Lwin, Thinzar M.; Miyake, Kentaro; Murakami, Takashi; DeLong, Jonathan C.; Yazaki, Paul J.; Shivley, John E.; Clary, Bryan; Hoffman, Robert M.; Bouvet, Michael

    2018-03-01

    Specific tumor targeting can result in selective labeling of cancer in vivo for surgical navigation. In the present study, we show that the use of an anti-CEA antibody conjugated to the near-infrared (NIR) fluorescent dye, IRDye800CW, can selectively target and label pancreatic cancer and its metastases in a clinically relevant patient derived xenograft mouse model.

  8. Structural and dynamical properties of liquid Al-Au alloys

    NASA Astrophysics Data System (ADS)

    Peng, H. L.; Voigtmann, Th.; Kolland, G.; Kobatake, H.; Brillo, J.

    2015-11-01

    We investigate temperature- and composition-dependent structural and dynamical properties of Al-Au melts. Experiments are performed to obtain accurate density and viscosity data. The system shows a strong negative excess volume, similar to other Al-based binary alloys. We develop a molecular-dynamics (MD) model of the melt based on the embedded-atom method (EAM), gauged against the available experimental liquid-state data. A rescaling of previous EAM potentials for solid-state Au and Al improves the quantitative agreement with experimental data in the melt. In the MD simulation, the admixture of Au to Al can be interpreted as causing a local compression of the less dense Al system, driven by less soft Au-Au interactions. This local compression provides a microscopic mechanism explaining the strong negative excess volume of the melt. We further discuss the concentration dependence of self- and interdiffusion and viscosity in the MD model. Al atoms are more mobile than Au, and their increased mobility is linked to a lower viscosity of the melt.

  9. Size exclusion chromatography for semipreparative scale separation of Au38(SR)24 and Au40(SR)24 and larger clusters.

    PubMed

    Knoppe, Stefan; Boudon, Julien; Dolamic, Igor; Dass, Amala; Bürgi, Thomas

    2011-07-01

    Size exclusion chromatography (SEC) on a semipreparative scale (10 mg and more) was used to size-select ultrasmall gold nanoclusters (<2 nm) from polydisperse mixtures. In particular, the ubiquitous byproducts of the etching process toward Au(38)(SR)(24) (SR, thiolate) clusters were separated and gained in high monodispersity (based on mass spectrometry). The isolated fractions were characterized by UV-vis spectroscopy, MALDI mass spectrometry, HPLC, and electron microscopy. Most notably, the separation of Au(38)(SR)(24) and Au(40)(SR)(24) clusters is demonstrated.

  10. Secondary ion mass spectroscopy study of Au trapping and migration in the Au-irradiated YBa2Cu3O7 - delta film

    NASA Astrophysics Data System (ADS)

    Li, Yupu; Kilner, J. A.; Liu, J. R.; Chu, W. K.; Wagner, G. A.; Somekh, R. E.

    1996-05-01

    The range data and migration of Au in YBa2Cu3O7-δ film were studied with implanted 197Au (1.5 MeV 5×1015 Au+/cm2) as a tracer. The film was a c-axis oriented film, ˜750 nm thick, deposited by high-pressure planar dc sputtering on <100> LaAlO3. Analysis by secondary ion mass spectroscopy shows that the as-implanted Au concentration distribution is essentially Gaussian-like and the depth (R̂p) of maximum Au concentration (˜1.2 wt %) is 201 nm. The projected range (R¯p) and (R̂p) are found to be in very good agreement with the simulated data by TRIM-95, whereas the measured ``straggle'' (ΔRp*) is about 20% larger than that by TRIM-95 simulation. It has also been found that the implanted 197Au starts to migrate within the film at a temperature between 650 and 700 °C, which is much higher than that for the implanted 2H (˜175 °C) and the implanted 18O (between 250 and 300 °C) in c-oriented YBa2Cu3O7-δ films.

  11. Using graphene-based plasmonic nanocomposites to quench energy from quantum dots for signal-on photoelectrochemical aptasensing.

    PubMed

    Zeng, Xianxiang; Ma, Shishi; Bao, Jianchun; Tu, Wenwen; Dai, Zhihui

    2013-12-17

    On the basis of the absorption and emission spectra overlap, an enhanced resonance energy transfer caused by excition-plasmon resonance between reduced graphene oxide (RGO)-Au nanoparticles (AuNPs) and CdTe quantum dots (QDs) was obtained. With the synergy of AuNPs and RGO as a planelike energy acceptor, it resulted in the enhancement of energy transfer between excited CdTe QDs and RGO-AuNPs nanocomposites. Upon the novel sandwichlike structure formed via DNA hybridization, the exciton produced in CdTe QDs was annihilated. A damped photocurrent was obtained, which was acted as the background signal for the development of a universal photoelectrochemical (PEC) platform. With the use of carcinoembryonic antigen (CEA) as a model which bonded to its specific aptamer and destroyed the sandwichlike structure, the energy transfer efficiency was lowered, leading to PEC response augment. Thus a signal-on PEC aptasensor was constructed. Under 470 nm irradiation at -0.05 V, the PEC aptasensor for CEA determination exhibited a linear range from 0.001 to 2.0 ng mL(-1) with a detection limit of 0.47 pg mL(-1) at a signal-to-noise ratio of 3 and was satisfactory for clinical sample detection. Since different aptamers can specifically bind to different target molecules, the designed strategy has an expansive application for the construction of versatile PEC platforms.

  12. An ultrasensitive luminol cathodic electrochemiluminescence immunosensor based on glucose oxidase and nanocomposites: graphene-carbon nanotubes and gold-platinum alloy.

    PubMed

    Jiang, Xinya; Chai, Yaqin; Yuan, Ruo; Cao, Yaling; Chen, Yingfeng; Wang, Haijun; Gan, Xianxue

    2013-06-14

    In the present study, a novel and ultrasensitive electrochemiluminescence (ECL) immunosensor based on luminol cathodic ECL was fabricated by using Au nanoparticles and Pt nanoparticles (nano-AuPt) electrodeposited on graphene-carbon nanotubes nanocomposite as platform for the detection of carcinoembryonic antigen (CEA). For this introduced immunosensor, graphene (GR) and single wall carbon nanotubes (CNTs) dispersed in chitosan (Chi-GR-CNTs) were firstly decorated on the bare gold electrode (GE) surface. Then nano-AuPt were electrodeposited (DpAu-Pt) on the Chi-GR-CNTs modified electrode. Subsequently, glucose oxidase (GOD) was employed to block the non-specific sites of electrode surface. When glucose was present in the working buffer solution, GOD immediately catalyzed the oxidation of glucose to in situ generate hydrogen peroxide (H2O2), which could subsequently promote the oxidation of luminol with an amplified cathodic ECL signal. The proposed immunosensor was performed at low potential (-0.1 to 0.4V) and low concentration of luminol. The CEA was determined in the range of 0.1 pg mL(-1) to 40 ng mL(-1) with a limit of detection down to 0.03 pg mL(-1) (SN(-1)=3). Moreover, with excellent sensitivity, selectivity, stability and simplicity, the as-proposed luminol-based ECL immunosensor provided great potential in clinical applications. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Cationic gemini surfactant-assisted synthesis of hollow Au nanostructures by stepwise reductions.

    PubMed

    Wang, Wentao; Han, Yuchun; Tian, Maozhang; Fan, Yaxun; Tang, Yongqiang; Gao, Mingyuan; Wang, Yilin

    2013-06-26

    A novel synthetic approach was developed for creating versatile hollow Au nanostructures by stepwise reductions of Au(III) upon the use of cationic gemini surfactant hexamethylene-1,6-bis(dodecyl dimethylammonium bromide) (C12C6C12Br2) as a template agent. It was observed that the Au(I) ions obtained from the reduction of Au(III) by ascorbic acid can assist the gemini surfactant to form vesicles, capsule-like, and tube-like aggregates that subsequently act as soft templates for hollow Au nanostructures upon further reduction of Au(I) to Au(0) by NaBH4. It was demonstrated that the combination of C12C6C12Br2 and Au(I) plays a key role in regulating the structure of the hollow precursors not only because C12C6C12Br2 has a stronger aggregation ability in comparison with its single chain counterpart but also because the electrostatic repulsion between head groups of C12C6C12Br2 is greatly weakened after Au(III) is converted to Au(I), which is in favor of the construction of vesicles, capsule-like, and tube-like aggregates. Compared with solid Au nanospheres, the resultant hollow nanostructures exhibit enhanced electrocatalytic activities in methanol oxidation, following the order of elongated nanocapsule > nanocapsule > nanosphere. Benefiting from balanced interactions between the gemini surfactant and Au(I), this soft-template method may present a facile and versatile approach for the controlled synthesis of Au nanostructures potentially useful for fuel cells and other Au nanodevices.

  14. Energy dependence of J/ψ production in Au + Au collisions at √{sNN} = 39 , 62.4 and 200GeV

    NASA Astrophysics Data System (ADS)

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Ajitanand, N. N.; Alekseev, I.; Anderson, D. M.; Aoyama, R.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Ashraf, M. U.; Attri, A.; Averichev, G. S.; Bai, X.; Bairathi, V.; Behera, A.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandenburg, J. D.; Brandin, A. V.; Brown, D.; Bunzarov, I.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chankova-Bunzarova, N.; Chatterjee, A.; Chattopadhyay, S.; Chen, X.; Chen, J. H.; Chen, X.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Elsey, N.; Engelage, J.; Eppley, G.; Esha, R.; Esumi, S.; Evdokimov, O.; Ewigleben, J.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Federicova, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Finch, E.; Fisyak, Y.; Flores, C. E.; Fujita, J.; Fulek, L.; Gagliardi, C. A.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Gupta, S.; Guryn, W.; Hamad, A. I.; Hamed, A.; Harlenderova, A.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Horvat, S.; Huang, B.; Huang, H. Z.; Huang, T.; Huang, X.; Humanic, T. J.; Huo, P.; Igo, G.; Jacobs, W. W.; Jentsch, A.; Jia, J.; Jiang, K.; Jowzaee, S.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z.; Kikoła, D. P.; Kisel, I.; Kisiel, A.; Kochenda, L.; Kocmanek, M.; Kollegger, T.; Kosarzewski, L. K.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kulathunga, N.; Kumar, L.; Kvapil, J.; Kwasizur, J. H.; Lacey, R.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, Y.; Li, X.; Li, W.; Li, C.; Lidrych, J.; Lin, T.; Lisa, M. A.; Liu, Y.; Liu, H.; Liu, F.; Liu, P.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, S.; Luo, X.; Ma, G. L.; Ma, L.; Ma, Y. G.; Ma, R.; Magdy, N.; Majka, R.; Mallick, D.; Margetis, S.; Markert, C.; Matis, H. S.; Meehan, K.; Mei, J. C.; Miller, Z. W.; Minaev, N. G.; Mioduszewski, S.; Mishra, D.; Mizuno, S.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nasim, Md.; Nayak, T. K.; Nelson, J. M.; Nie, M.; Nigmatkulov, G.; Niida, T.; Nogach, L. V.; Nonaka, T.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V. A.; Olvitt, D.; Page, B. S.; Pak, R.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Pile, P.; Pluta, J.; Poniatowska, K.; Porter, J.; Posik, M.; Pruthi, N. K.; Przybycien, M.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Ray, R. L.; Reed, R.; Rehbein, M. J.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Roth, J. D.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Salur, S.; Sandweiss, J.; Saur, M.; Schambach, J.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Schweid, B. R.; Seger, J.; Sergeeva, M.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, A.; Sharma, M. K.; Shen, W. Q.; Shi, S. S.; Shi, Z.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Singha, S.; Skoby, M. J.; Smirnov, N.; Smirnov, D.; Solyst, W.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Strikhanov, M.; Stringfellow, B.; Sugiura, T.; Sumbera, M.; Summa, B.; Sun, X.; Sun, Y.; Sun, X. M.; Surrow, B.; Svirida, D. N.; Tang, A. H.; Tang, Z.; Taranenko, A.; Tarnowsky, T.; Tawfik, A.; Thäder, J.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Todoroki, T.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Trzeciak, B. A.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vasiliev, A. N.; Videbæk, F.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, G.; Wang, Y.; Wang, F.; Wang, Y.; Webb, J. C.; Webb, G.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xiao, Z. G.; Xie, W.; Xie, G.; Xu, J.; Xu, N.; Xu, Q. H.; Xu, Y. F.; Xu, Z.; Yang, Y.; Yang, Q.; Yang, C.; Yang, S.; Ye, Z.; Ye, Z.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, Z.; Zhang, X. P.; Zhang, J. B.; Zhang, S.; Zhang, J.; Zhang, Y.; Zhang, J.; Zhang, S.; Zhao, J.; Zhong, C.; Zhou, L.; Zhou, C.; Zhu, X.; Zhu, Z.; Zyzak, M.; STAR Collaboration

    2017-08-01

    The inclusive J / ψ transverse momentum spectra and nuclear modification factors are reported at mid-rapidity (| y | < 1.0) in Au + Au collisions at √{sNN} = 39, 62.4 and 200 GeV taken by the STAR experiment. A suppression of J / ψ production, with respect to the production in p + p scaled by the number of binary nucleon-nucleon collisions, is observed in central Au + Au collisions at these three energies. No significant energy dependence of nuclear modification factors is found within uncertainties. The measured nuclear modification factors can be described by model calculations that take into account both suppression of direct J / ψ production due to the color screening effect and J / ψ regeneration from recombination of uncorrelated charm-anticharm quark pairs.

  15. Nonlinear absorption enhancement of AuNPs based polymer nanocomposites

    NASA Astrophysics Data System (ADS)

    Zulina, Natalia A.; Baranov, Mikhail A.; Kniazev, Kirill I.; Kaliabin, Viacheslav O.; Denisyuk, Igor Yu.; Achor, Susan U.; Sitnikova, Vera E.

    2018-07-01

    Au nanoparticles (AuNPs) based polymer nanocomposites with high nonlinear absorption coefficient were synthesized by UV-photocuring. AuNPs were synthesized by laser ablation method in liquid monomer isodecyl acrylate (IDA). In this research, two colloids with 70 nm and 20 nm nanoparticles average sizes were studied. Size control was performed with SEM and STEM. Prepared nanomaterials exhibit strong third-order nonlinear optical responses under CW laser irradiation at 532 nm, which was estimated by using z-scan technique performed with open aperture. It was found experimentally that nonlinear absorption β is almost twice higher for nanocomposites with smaller AuNPs.

  16. Divided café-au-lait macule of the mouth.

    PubMed

    Sergay, Amanda; Silverberg, Nanette B

    2007-05-01

    We describe a 4-year-old, otherwise healthy boy with a congenital history of a perioral and labial segmental café-au-lait macule, who was noted to have unilateral localized gingival hyperpigmentation that aligned with the café-au-lait macule. This case is highly illustrative of the embryologic timing of the genetic event locally, which leads to café-au-lait type hyperpigmentation. Because the facial features and the ectoderm overlying the facial muscles develop around the third to fourth week of gestation, the distribution of this café-au-lait macule suggests development at the same time.

  17. Spin Polarization and Quantum Spins in Au Nanoparticles

    PubMed Central

    Li, Chi-Yen; Karna, Sunil K.; Wang, Chin-Wei; Li, Wen-Hsien

    2013-01-01

    The present study focuses on investigating the magnetic properties and the critical particle size for developing sizable spontaneous magnetic moment of bare Au nanoparticles. Seven sets of bare Au nanoparticle assemblies, with diameters from 3.5 to 17.5 nm, were fabricated with the gas condensation method. Line profiles of the X-ray diffraction peaks were used to determine the mean particle diameters and size distributions of the nanoparticle assemblies. The magnetization curves M(Ha) reveal Langevin field profiles. Magnetic hysteresis was clearly revealed in the low field regime even at 300 K. Contributions to the magnetization from different size particles in the nanoparticle assemblies were considered when analyzing the M(Ha) curves. The results show that the maximum particle moment will appear in 2.4 nm Au particles. A similar result of the maximum saturation magnetization appearing in 2.3 nm Au particles is also concluded through analysis of the dependency of the saturation magnetization MP on particle size. The MP(d) curve departs significantly from the 1/d dependence, but can be described by a log-normal function. Magnetization can be barely detected for Au particles larger than 27 nm. Magnetic field induced Zeeman magnetization from the quantum confined Kubo gap opening appears in Au nanoparticles smaller than 9.5 nm in diameter. PMID:23989607

  18. Foreword

    NASA Astrophysics Data System (ADS)

    Boutron, Claude; Ferrari, Christophe

    2003-05-01

    Informatique, Biologie et Médecine, et Sciences de la Terre et de l'Univers. Il y a deux grandes Universités Scientifiques de renommée internationale: l'Université Joseph Fourier (UJF) et l'Institut National Polytechnique de Grenoble (INPG). Il y a aussi d'importants laboratoires de différents organismes publics français et européen comme le Commissariat à l'Énergie Atomique (CEA), le Centre National de la Recherche Scientifique (CNRS), l'Institut Laue Langevin (ILL), l'European Synchrotron Radiation Facility (ESRF) et l'Institut de Radio-Astronomie Millimètrique (IRAM). C'est aussi le lieu d'implantation de nombreuses sociétés de haute technologie comme Hewlett Packard, ST Microelectronics, Schneider Electric and SGS-Thomson. Il a à Grenoble une longue tradition de recherches dans le domaine des métaux lourds dans l'environnement, notamment au Laboratoire de Glaciologie et Géophysique de l'Environnement et au Laboratoire de Géophysique Interne et Tectonophysique. Ces deux volumes regroupent les articles issus de communication présentées aussi bien au cours des sessions orales que des sessions posters. Ces articles sont classés selon l'ordre alphabétique du nom de famille du premier auteur. Nous remercions vivement les auteurs pour l'excellente qualité de ces articles. Nous remercions aussi tout particulièrement Isabelle Houlbert et Laurence Castagné pour leur collaboration. Nous aimerions aussi remercier les membres du comité d'organisation ainsi que Jerome Nriagu (organisateur de la 11e conférence) pour l'aide apportée à l'organisation de cette conférence. Nous remercions aussi tout spécialement Christine Echevet qui n'a pas ménagé ses efforts pour faire de cette conférence un succés, ainsi que de nombreux collègues du Laboratoire de Glaciologie et Géophysique de l'Environnement, en particulier Jocelyne Roquemora. Nous tenons également à remercier le Président de Grenoble Alpes Métropole et le Maire de la Ville de Grenoble pour leur

  19. Glucose-functionalized Au nanoprisms for optoacoustic imaging and near-infrared photothermal therapy

    NASA Astrophysics Data System (ADS)

    Han, Jishu; Zhang, Jingjing; Yang, Meng; Cui, Daxiang; de La Fuente, Jesus M.

    2015-12-01

    Targeted imaging and tumor therapy using nanomaterials has stimulated research interest recently, but the high cytotoxicity and low cellular uptake of nanomaterials limit their bioapplication. In this paper, glucose (Glc) was chosen to functionalize Au nanoprisms (NPrs) for improving the cytotoxicity and cellular uptake of Au@PEG-Glc NPrs into cancer cells. Glucose is a primary source of energy at the cellular level and at cellular membranes for cell recognition. A coating of glucose facilitates the accumulation of Au@PEG-Glc NPrs in a tumor region much more than Au@PEG NPrs. Due to the high accumulation and excellent photoabsorbing property of Au@PEG-Glc NPrs, enhanced optoacoustic imaging of a tumor in vivo was achieved, and visualization of the tumor further guided cancer treatment. Based on the optical-thermal conversion performance of Au@PEG-Glc NPrs, the tumor in vivo was effectively cured through photothermal therapy. The current work demonstrates the great potential of Au@PEG-Glc NPrs in optoacoustic imaging and photothermal cancer therapy in future.Targeted imaging and tumor therapy using nanomaterials has stimulated research interest recently, but the high cytotoxicity and low cellular uptake of nanomaterials limit their bioapplication. In this paper, glucose (Glc) was chosen to functionalize Au nanoprisms (NPrs) for improving the cytotoxicity and cellular uptake of Au@PEG-Glc NPrs into cancer cells. Glucose is a primary source of energy at the cellular level and at cellular membranes for cell recognition. A coating of glucose facilitates the accumulation of Au@PEG-Glc NPrs in a tumor region much more than Au@PEG NPrs. Due to the high accumulation and excellent photoabsorbing property of Au@PEG-Glc NPrs, enhanced optoacoustic imaging of a tumor in vivo was achieved, and visualization of the tumor further guided cancer treatment. Based on the optical-thermal conversion performance of Au@PEG-Glc NPrs, the tumor in vivo was effectively cured through

  20. Improvement on electrical conductivity and electron field emission properties of Au-ion implanted ultrananocrystalline diamond films by using Au-Si eutectic substrates

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sankaran, K. J.; Institute for Materials Research; Sundaravel, B.

    2015-08-28

    In the present work, Au-Si eutectic layer was used to enhance the electrical conductivity/electron field emission (EFE) properties of Au-ion implanted ultrananocrystalline diamond (Au-UNCD) films grown on Si substrates. The electrical conductivity was improved to a value of 230 (Ω cm){sup −1}, and the EFE properties was enhanced reporting a low turn-on field of 2.1 V/μm with high EFE current density of 5.3 mA/cm{sup 2} (at an applied field of 4.9 V/μm) for the Au-UNCD films. The formation of SiC phase circumvents the formation of amorphous carbon prior to the nucleation of diamond on Si substrates. Consequently, the electron transport efficiency of themore » UNCD-to-Si interface increases, thereby improving the conductivity as well as the EFE properties. Moreover, the salient feature of these processes is that the sputtering deposition of Au-coating for preparing the Au-Si interlayer, the microwave plasma enhanced chemical vapor deposition process for growing the UNCD films, and the Au-ion implantation process for inducing the nanographitic phases are standard thin film preparation techniques, which are simple, robust, and easily scalable. The availability of these highly conducting UNCD films with superior EFE characteristics may open up a pathway for the development of high-definition flat panel displays and plasma devices.« less

  1. Tri-metallic PtPdAu mesoporous nanoelectrocatalysts.

    PubMed

    Li, Chunjie; Wang, Hongjing; Li, Yinghao; Yu, Hongjie; Yin, Shuli; Xue, Hairong; Li, Xiaonian; Xu, You; Wang, Liang

    2018-06-22

    The design of mesoporous materials with multi-metallic compositions is highly important for various electrocatalytic applications. In this paper, we demonstrate an efficient method to directly fabricate tri-metallic PtPdAu mesoporous nanoparticles (PtPdAu MNs) in a high yield, which is simply performed by heating treatment of the reaction mixture aqueous solution at 40 °C for 4 h. Profiting from its mesoporous structure and multi-metallic components, the as-prepared PtPdAu MNs exhibit enhanced electrocatalytic activities toward both methanol oxidation reaction and oxygen reduction reaction in comparison with bi-metallic PtPd MNs and commercial Pt/C catalyst.

  2. Tri-metallic PtPdAu mesoporous nanoelectrocatalysts

    NASA Astrophysics Data System (ADS)

    Li, Chunjie; Wang, Hongjing; Li, Yinghao; Yu, Hongjie; Yin, Shuli; Xue, Hairong; Li, Xiaonian; Xu, You; Wang, Liang

    2018-06-01

    The design of mesoporous materials with multi-metallic compositions is highly important for various electrocatalytic applications. In this paper, we demonstrate an efficient method to directly fabricate tri-metallic PtPdAu mesoporous nanoparticles (PtPdAu MNs) in a high yield, which is simply performed by heating treatment of the reaction mixture aqueous solution at 40 °C for 4 h. Profiting from its mesoporous structure and multi-metallic components, the as-prepared PtPdAu MNs exhibit enhanced electrocatalytic activities toward both methanol oxidation reaction and oxygen reduction reaction in comparison with bi-metallic PtPd MNs and commercial Pt/C catalyst.

  3. Registration of ‘AU-1101’ peanut

    USDA-ARS?s Scientific Manuscript database

    AU-1101’ (Reg. No. CV-xxx, PI 661498) is a large-seeded virginia-type peanut (Arachis hypogaea L. subsp. hypogaea var. hypogaea) with high yield and medium maturity, uniform pod size and shape, high grade, superior shelling characters, low oil content, normal oleic acid content, and good flavor. AU-...

  4. Measurements of electrons from semi-leptonic heavy flavor decays in p+p and Au+Au collisions at √{sNN } = 200 GeV at STAR

    NASA Astrophysics Data System (ADS)

    Wang, Yaping; STAR Collaboration

    2017-08-01

    In these proceedings, we present recent results on electrons from semi-leptonic decays of open heavy-flavor hadrons (eHF) with the STAR detector at the Relativistic Heavy Ion Collider. We report the updated measurements of eHF production in p+p collisions at √{ s } = 200 GeV with significantly improved precision and wider kinematic coverage than previous measurements. With this new p+p reference, we obtain the nuclear modification factor (RAA) for eHF in Au+Au collisions at √{sNN } = 200 GeV using 2010 data. The RAA shows significant suppression at high pT in most central Au+Au collisions, while the suppression reduces gradually towards more peripheral collisions. We compare eHFRAA in central Au+Au collisions to that in central U+U collisions at √{sNN } = 193 GeV and find that they are consistent within uncertainties. We also show the results of B-hadron contribution to eHF extracted from azimuthal correlations between eHF and charged hadrons in p+p collisions. Finally we report the measurements of eHF from open bottom hadron decays and discuss the prospect of measuring eHF from open bottom and charm hadron decays separately utilizing the Heavy Flavor Tracker in Au+Au collisions.

  5. The coupled geochemistry of Au and As in pyrite from hydrothermal ore deposits

    NASA Astrophysics Data System (ADS)

    Deditius, Artur P.; Reich, Martin; Kesler, Stephen E.; Utsunomiya, Satoshi; Chryssoulis, Stephen L.; Walshe, John; Ewing, Rodney C.

    2014-09-01

    The ubiquity of Au-bearing arsenian pyrite in hydrothermal ore deposits suggests that the coupled geochemical behaviour of Au and As in this sulfide occurs under a wide range of physico-chemical conditions. Despite significant advances in the last 20 years, fundamental factors controlling Au and As ratios in pyrite from ore deposits remain poorly known. Here we explore these constraints using new and previously published EMPA, LA-ICP-MS, SIMS, and μ-PIXE analyses of As and Au in pyrite from Carlin-type Au, epithermal Au, porphyry Cu, Cu-Au, and orogenic Au deposits, volcanogenic massive sulfide (VHMS), Witwatersrand Au, iron oxide copper gold (IOCG), and coal deposits. Pyrite included in the data compilation formed under temperatures from ∼30 to ∼600 °C and in a wide variety of geological environments. The pyrite Au-As data form a wedge-shaped zone in compositional space, and the fact that most data points plot below the solid solubility limit defined by Reich et al. (2005) indicate that Au1+ is the dominant form of Au in arsenian pyrite and that Au-bearing ore fluids that deposit this sulfide are mostly undersaturated with respect to native Au. The analytical data also show that the solid solubility limit of Au in arsenian pyrite defined by an Au/As ratio of 0.02 is independent of the geochemical environment of pyrite formation and rather depends on the crystal-chemical properties of pyrite and post-depositional alteration. Compilation of Au-As concentrations and formation temperatures for pyrite indicates that Au and As solubility in pyrite is retrograde; Au and As contents decrease as a function of increasing temperature from ∼200 to ∼500 °C. Based on these results, two major Au-As trends for Au-bearing arsenian pyrite from ore deposits are defined. One trend is formed by pyrites from Carlin-type and orogenic Au deposits where compositions are largely controlled by fluid-rock interactions and/or can be highly perturbed by changes in temperature and

  6. Elliptic Flow of Identified Hadrons in Au+Au Collisions at (sNN)=200 GeV

    NASA Astrophysics Data System (ADS)

    Adler, S. S.; Afanasiev, S.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Alexander, J.; Amirikas, R.; Aphecetche, L.; Aronson, S. H.; Averbeck, R.; Awes, T. C.; Azmoun, R.; Babintsev, V.; Baldisseri, A.; Barish, K. N.; Barnes, P. D.; Bassalleck, B.; Bathe, S.; Batsouli, S.; Baublis, V.; Bazilevsky, A.; Belikov, S.; Berdnikov, Y.; Bhagavatula, S.; Boissevain, J. G.; Borel, H.; Borenstein, S.; Brooks, M. L.; Brown, D. S.; Bruner, N.; Bucher, D.; Buesching, H.; Bumazhnov, V.; Bunce, G.; Burward-Hoy, J. M.; Butsyk, S.; Camard, X.; Chai, J.-S.; Chand, P.; Chang, W. C.; Chernichenko, S.; Chi, C. Y.; Chiba, J.; Chiu, M.; Choi, I. J.; Choi, J.; Choudhury, R. K.; Chujo, T.; Cianciolo, V.; Cobigo, Y.; Cole, B. A.; Constantin, P.; D'Enterria, D. G.; David, G.; Delagrange, H.; Denisov, A.; Deshpande, A.; Desmond, E. J.; Dietzsch, O.; Drapier, O.; Drees, A.; Du Rietz, R.; Durum, A.; Dutta, D.; Efremenko, Y. V.; El Chenawi, K.; Enokizono, A.; En'yo, H.; Esumi, S.; Ewell, L.; Fields, D. E.; Fleuret, F.; Fokin, S. L.; Fox, B. D.; Fraenkel, Z.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fung, S.-Y.; Garpman, S.; Ghosh, T. K.; Glenn, A.; Gogiberidze, G.; Gonin, M.; Gosset, J.; Goto, Y.; Granier de Cassagnac, R.; Grau, N.; Greene, S. V.; Grosse Perdekamp, M.; Guryn, W.; Gustafsson, H.-Å.; Hachiya, T.; Haggerty, J. S.; Hamagaki, H.; Hansen, A. G.; Hartouni, E. P.; Harvey, M.; Hayano, R.; He, X.; Heffner, M.; Hemmick, T. K.; Heuser, J. M.; Hibino, M.; Hill, J. C.; Holzmann, W.; Homma, K.; Hong, B.; Hoover, A.; Ichihara, T.; Ikonnikov, V. V.; Imai, K.; Isenhower, L. D.; Ishihara, M.; Issah, M.; Isupov, A.; Jacak, B. V.; Jang, W. Y.; Jeong, Y.; Jia, J.; Jinnouchi, O.; Johnson, B. M.; Johnson, S. C.; Joo, K. S.; Jouan, D.; Kametani, S.; Kamihara, N.; Kang, J. H.; Kapoor, S. S.; Katou, K.; Kelly, S.; Khachaturov, B.; Khanzadeev, A.; Kikuchi, J.; Kim, D. H.; Kim, D. J.; Kim, D. W.; Kim, E.; Kim, G.-B.; Kim, H. J.; Kistenev, E.; Kiyomichi, A.; Kiyoyama, K.; Klein-Boesing, C.; Kobayashi, H.; Kochenda, L.; Kochetkov, V.; Koehler, D.; Kohama, T.; Kopytine, M.; Kotchetkov, D.; Kozlov, A.; Kroon, P. J.; Kuberg, C. H.; Kurita, K.; Kuroki, Y.; Kweon, M. J.; Kwon, Y.; Kyle, G. S.; Lacey, R.; Ladygin, V.; Lajoie, J. G.; Lebedev, A.; Leckey, S.; Lee, D. M.; Lee, S.; Leitch, M. J.; Li, X. H.; Lim, H.; Litvinenko, A.; Liu, M. X.; Liu, Y.; Maguire, C. F.; Makdisi, Y. I.; Malakhov, A.; Manko, V. I.; Mao, Y.; Martinez, G.; Marx, M. D.; Masui, H.; Matathias, F.; Matsumoto, T.; McGaughey, P. L.; Melnikov, E.; Messer, F.; Miake, Y.; Milan, J.; Miller, T. E.; Milov, A.; Mioduszewski, S.; Mischke, R. E.; Mishra, G. C.; Mitchell, J. T.; Mohanty, A. K.; Morrison, D. P.; Moss, J. M.; Mühlbacher, F.; Mukhopadhyay, D.; Muniruzzaman, M.; Murata, J.; Nagamiya, S.; Nagle, J. L.; Nakamura, T.; Nandi, B. K.; Nara, M.; Newby, J.; Nilsson, P.; Nyanin, A. S.; Nystrand, J.; O'Brien, E.; Ogilvie, C. A.; Ohnishi, H.; Ojha, I. D.; Okada, K.; Ono, M.; Onuchin, V.; Oskarsson, A.; Otterlund, I.; Oyama, K.; Ozawa, K.; Pal, D.; Palounek, A. P.; Pantuev, V. S.; Papavassiliou, V.; Park, J.; Parmar, A.; Pate, S. F.; Peitzmann, T.; Peng, J.-C.; Peresedov, V.; Pinkenburg, C.; Pisani, R. P.; Plasil, F.; Purschke, M. L.; Purwar, A.; Rak, J.; Ravinovich, I.; Read, K. F.; Reuter, M.; Reygers, K.; Riabov, V.; Riabov, Y.; Roche, G.; Romana, A.; Rosati, M.; Rosnet, P.; Ryu, S. S.; Sadler, M. E.; Saito, N.; Sakaguchi, T.; Sakai, M.; Sakai, S.; Samsonov, V.; Sanfratello, L.; Santo, R.; Sato, H. D.; Sato, S.; Sawada, S.; Schutz, Y.; Semenov, V.; Seto, R.; Shaw, M. R.; Shea, T. K.; Shibata, T.-A.; Shigaki, K.; Shiina, T.; Silva, C. L.; Silvermyr, D.; Sim, K. S.; Singh, C. P.; Singh, V.; Sivertz, M.; Soldatov, A.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Sourikova, I. V.; Staley, F.; Stankus, P. W.; Stenlund, E.; Stepanov, M.; Ster, A.; Stoll, S. P.; Sugitate, T.; Sullivan, J. P.; Takagui, E. M.; Taketani, A.; Tamai, M.; Tanaka, K. H.; Tanaka, Y.; Tanida, K.; Tannenbaum, M. J.; Tarján, P.; Tepe, J. D.; Thomas, T. L.; Tojo, J.; Torii, H.; Towell, R. S.; Tserruya, I.; Tsuruoka, H.; Tuli, S. K.; Tydesjö, H.; Tyurin, N.; van Hecke, H. W.; Velkovska, J.; Velkovsky, M.; Villatte, L.; Vinogradov, A. A.; Volkov, M. A.; Vznuzdaev, E.; Wang, X. R.; Watanabe, Y.; White, S. N.; Wohn, F. K.; Woody, C. L.; Xie, W.; Yang, Y.; Yanovich, A.; Yokkaichi, S.; Young, G. R.; Yushmanov, I. E.; Zajc, W. A.; Zhang, C.; Zhou, S.; Zolin, L.

    2003-10-01

    The anisotropy parameter (v2), the second harmonic of the azimuthal particle distribution, has been measured with the PHENIX detector in Au+Au collisions at (sNN)=200 GeV for identified and inclusive charged particle production at central rapidities (|η|<0.35) with respect to the reaction plane defined at high rapidities (|η|=3 4 ). We observe that the v2 of mesons falls below that of (anti)baryons for pT>2 GeV/c, in marked contrast to the predictions of a hydrodynamical model. A quark-coalescence model is also investigated.

  7. Assembling Bare Au Nanoparticles at Positively Charged Templates

    DOE PAGES

    Wang, Wenjie; Zhang, Honghu; Kuzmenko, Ivan; ...

    2016-05-26

    In-situ X-ray reflectivity (XRR) and grazing incidence X-ray small-angle scattering (GISAXS) reveal that unfunctionalized (bare) gold nanoparticles (AuNP) spontaneously adsorb to a cationic lipid template formed by a Langmuir monolayer of DPTAP (1,2-dihexadecanoyl-3-trimethylammonium-propane) at vapor/aqueous interfaces. Analysis of the XRR yields the electron density profile across the charged-interfaces along the surface normal showing the AuNPs assemble with vertical thickness comparable to the particle size. The GISAXS analysis indicates that the adsorbed mono-particle layer exhibits short-range in-plane correlations. By contrast, single-stranded DNA-functionalized AuNPs, while attracted to the positively charged surface (more efficiently with the addition of salt to the solution), displaymore » less in-plane regular packing compared to bare AuNPs.« less

  8. Single electron yields from semileptonic charm and bottom hadron decays in Au + Au collisions at s N N = 200 GeV

    DOE PAGES

    Adare, A.; Aidala, C.; Ajitanand, N. N.; ...

    2016-03-07

    We measured open heavy flavor production in minimum bias Au + Au collisions at √s( NN) = 200 GeV via the yields of electrons from semileptonic decays of charm and bottom hadrons, using the PHENIX Collaboration at the Relativistic Heavy Ion Collider. In the past, heavy flavor electron measurements indicated substantial modification in the momentum distribution of the parent heavy quarks owing to the quark-gluon plasma created in these collisions. For the first time, using the PHENIX silicon vertex detector to measure precision displaced tracking, the relative contributions from charm and bottom hadrons to these electrons as a function ofmore » transverse momentum are measured in Au + Au collisions. Here, we compare the fraction of electrons from bottom hadrons to previously published results extracted from electron-hadron correlations in p + p collisions at √s( NN) = 200 GeV and find the fractions to be similar within the large uncertainties on both measurements for p (T) > 4 GeV/c. We use the bottom electron fractions in Au + Au and p + p along with the previously measured heavy flavor electron R (AA) to calculate the R (AA) for electrons from charm and bottom hadron decays separately. Finally, we find that electrons from bottom hadron decays are less suppressed than those from charm for the region 3 < p (T) < 4 GeV/c.« less

  9. Nanogold-functionalized DNAzyme concatamers with redox-active intercalators for quadruple signal amplification of electrochemical immunoassay.

    PubMed

    Zhou, Jun; Lai, Wenqiang; Zhuang, Junyang; Tang, Juan; Tang, Dianping

    2013-04-10

    A novel and in situ amplified immunoassay strategy with quadruple signal amplification was designed for highly efficient electrochemical detection of low-abundance proteins (carcinoembryonic antigen, CEA, as a model) by using nanogold-functionalized DNAzyme concatamers with redox-active intercalators. To construct such an in situ amplification system, streptavidin-labeled gold nanoparticles (AuNP-SA) were initially used for the labelling of initiator strands (S0) and detection antibody (mAb2) with a large ratio (mAb2-AuNP-S0), and then two auxiliary DNA strands S1 and S2 were designed for in situ propagation of DNAzyme concatamers with the hemin/G-quadruplex format. The quadruple signal amplification was implemented by using the avidin-biotin chemistry, nanogold labels, DNA concatamers, and DNAzymes. In the presence of target CEA, the sandwiched immunocomplex was formed between the immobilized primary antibodies on the electrode and the conjugated detection antibodies on the mAb2-AuNP-S0. The carried S0 initiator strands could progress a chain reaction of hybridization events between alternating S1/S2 DNA strands to form a nicked double-helix. Upon addition of hemin, the hemin-binding aptamers could be bound to form the hemin/G-quadruplex-based DNAzymes. The formed double-helix DNA polymers could cause the intercalation of numerous electroactive methylene blue molecules. During the electrochemical measurement, the formed DNAzymes could catalyze the reduction of H2O2 in the solution to amplify the electrochemical signal of the intercalated methylene blue. Under optimal conditions, the electrochemical immunoassay exhibited a wide dynamic range of 1.0 fg mL(-1) to 20 ng mL(-1) toward CEA standards with a low detection limit of 0.5 fg mL(-1). Intra-assay and inter-assay coefficients of variation (CV) were less than 8.5% and 11.5%, respectively. No significant differences at the 0.05 significance level were encountered in the analysis of 14 clinical serum specimens

  10. Structural, electronic and magnetic properties of Au-based monolayer derivatives in honeycomb structure

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kapoor, Pooja, E-mail: pupooja16@gmail.com; Sharma, Munish; Ahluwalia, P. K.

    2016-05-23

    We present electronic properties of atomic layer of Au, Au{sub 2}-N, Au{sub 2}-O and Au{sub 2}-F in graphene-like structure within the framework of density functional theory (DFT). The lattice constant of derived monolayers are found to be higher than the pristine Au monolayer. Au monolayer is metallic in nature with quantum ballistic conductance calculated as 4G{sub 0}. Similarly, Au{sub 2}-N and Au{sub 2}-F monolayers show 4G{sub 0} and 2G{sub 0} quantum conductance respectively while semiconducting nature with calculated band gap of 0.28 eV has been observed for Au{sub 2}-O monolayer. Most interestingly, half metalicity has been predicted for Au{sub 2}-Nmore » and Au{sub 2}-F monolayers. Our findings may have importance for the application of these monolayers in nanoelectronic and spintronics.« less

  11. Azimuthal Anisotropy in U +U and Au +Au Collisions at RHIC

    NASA Astrophysics Data System (ADS)

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Alford, J.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Averichev, G. S.; Banerjee, A.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandin, A. V.; Bunzarov, I.; Burton, T. P.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Cervantes, M. C.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chattopadhyay, S.; Chen, J. H.; Chen, X.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; di Ruzza, B.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Engelage, J.; Eppley, G.; Esha, R.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Fisyak, Y.; Flores, C. E.; Fulek, L.; Gagliardi, C. A.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, S.; Gupta, A.; Guryn, W.; Hamad, A.; Hamed, A.; Haque, R.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Hofman, D. J.; Horvat, S.; Huang, H. Z.; Huang, B.; Huang, X.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Jiang, K.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z. H.; Kikola, D. P.; Kisel, I.; Kisiel, A.; Koetke, D. D.; Kollegger, T.; Kosarzewski, L. K.; Kotchenda, L.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kulakov, I.; Kumar, L.; Kycia, R. A.; Lamont, M. A. C.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, W.; Li, Y.; Li, C.; Li, Z. M.; Li, X.; Li, X.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Ma, L.; Ma, R.; Ma, Y. G.; Ma, G. L.; Magdy, N.; Majka, R.; Manion, A.; Margetis, S.; Markert, C.; Masui, H.; Matis, H. S.; McDonald, D.; Meehan, K.; Minaev, N. G.; Mioduszewski, S.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nigmatkulov, G.; Nogach, L. V.; Noh, S. Y.; Novak, J.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V.; Olvitt, D. L.; Page, B. S.; Pak, R.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Peterson, A.; Pile, P.; Planinic, M.; Pluta, J.; Poljak, N.; Poniatowska, K.; Porter, J.; Posik, M.; Poskanzer, A. M.; Pruthi, N. K.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Raniwala, S.; Raniwala, R.; Ray, R. L.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Roy, A.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, B.; Sharma, M. K.; Shen, W. Q.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Skoby, M. J.; Smirnov, D.; Smirnov, N.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stepanov, M.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Sumbera, M.; Summa, B. J.; Sun, X.; Sun, X. M.; Sun, Z.; Sun, Y.; Surrow, B.; Svirida, D. N.; Szelezniak, M. A.; Tang, Z.; Tang, A. H.; Tarnowsky, T.; Tawfik, A. N.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Trzeciak, B. A.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vandenbroucke, M.; Varma, R.; Vasiliev, A. N.; Vertesi, R.; Videbaek, F.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, F.; Wang, Y.; Wang, H.; Wang, J. S.; Wang, Y.; Wang, G.; Webb, G.; Webb, J. C.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y. F.; Xiao, Z.; Xie, W.; Xin, K.; Xu, Y. F.; Xu, N.; Xu, Z.; Xu, Q. H.; Xu, H.; Yang, Y.; Yang, Y.; Yang, C.; Yang, S.; Yang, Q.; Ye, Z.; Yepes, P.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, X. P.; Zhang, J. B.; Zhang, J.; Zhang, Z.; Zhang, S.; Zhang, Y.; Zhang, J. L.; Zhao, F.; Zhao, J.; Zhong, C.; Zhou, L.; Zhu, X.; Zoulkarneeva, Y.; Zyzak, M.; STAR Collaboration

    2015-11-01

    Collisions between prolate uranium nuclei are used to study how particle production and azimuthal anisotropies depend on initial geometry in heavy-ion collisions. We report the two- and four-particle cumulants, v2{2 } and v2{4 }, for charged hadrons from U +U collisions at √{sNN }=193 GeV and Au +Au collisions at √{sNN}=200 GeV . Nearly fully overlapping collisions are selected based on the energy deposited by spectators in zero degree calorimeters (ZDCs). Within this sample, the observed dependence of v2{2 } on multiplicity demonstrates that ZDC information combined with multiplicity can preferentially select different overlap configurations in U +U collisions. We also show that v2 vs multiplicity can be better described by models, such as gluon saturation or quark participant models, that eliminate the dependence of the multiplicity on the number of binary nucleon-nucleon collisions.

  12. Au-nanocluster emission based glucose sensing.

    PubMed

    Hussain, A M P; Sarangi, S N; Kesarwani, J A; Sahu, S N

    2011-11-15

    Fabrication of a glucose biosensor based on Au-cluster emission quenching in the UV region is reported. The glucose biosensor is highly sensitive to β-d-glucose in 2.5-25.0mM range as confirmed from a linear calibration plot between Au-cluster colloid emission intensity as a function of β-d-glucose concentration. The interaction of β-d-glucose with l-cysteine capped Au cluster colloids has been confirmed from their Fourier transformed infrared spectroscopy (FTIR) measurements. It has been found that the biomolecules present in the serum such as ascorbic and uric acids, proteins and peptides do not interfere and affect in glucose estimation as confirmed from their absorption and fluorescence (FL) emission measurements. Practical utility of this sensor based on FL quenching method has been demonstrated by estimating the glucose level in human serum that includes diabetes and the data were found to be comparable or more accurate than those of the pathological data obtained from a local hospital. In addition, this biosensor is useful to detect glucose level over a wide range with sensor response time of the order of nano to picoseconds that is emission lifetime of Au clusters. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Gold nanoparticle-based low limit of detection Love wave biosensor for carcinoembryonic antigens.

    PubMed

    Li, Shuangming; Wan, Ying; Su, Yan; Fan, Chunhai; Bhethanabotla, Venkat R

    2017-09-15

    In this work, a Love wave biosensing platform is described for detecting cancer-related biomarker carcinoembryonic antigen (CEA). An ST 90°-X quartz Love wave device with a layer of SiO 2 waveguide was combined with gold nanoparticles (Au NPs) to amplify the mass loading effect of the acoustic wave sensor to achieve a limit of detection of 37pg/mL. The strategy involves modifying the Au NPs with anti-CEA antibody conjugates to form nanoprobes in a sandwich immunoassay. The unamplified detection limit of the Love wave biosensor is 9.4ng/mL. This 2-3 order of magnitude reduction in the limit of detection brings the SAW platform into the range useful for clinical diagnosis. Measurement electronics and microfluidics are easily constructed for acoustic wave biosensors, such as the Love wave device described here, allowing for robust platforms for point of care applications for cancer biomarkers in general. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. The fabrication of nanopatterns with Au nanoparticles-embedded micelles via nanoimprint lithography.

    PubMed

    Lee, Jung-Pil; Kim, Eun-Uk; Koh, Haeng-Deog; Kang, Nam-Goo; Jung, Gun-Young; Lee, Jae-Suk

    2009-09-09

    We fabricated nanopatterns with Au nanoparticles-embedded micelles (Au-micelles) by self-assembly of block copolymers via nanoimprint lithography. The micelle structure prepared by self-assembled block copolymers was used as a template for the synthesis of Au nanoparticles (Au NPs). Au NPs were synthesized in situ inside the micelles of polystyrene-block-poly(2-vinylpyridine) (PS- b-P2VP). Au-micelles were arranged on the trenches of the polymer template, which was imprinted by nanoimprint lithography. The fabrication of line-type and dot-type nanopatterns was carried out by the combined method. In addition, multilayer nanopatterns of the Au-micelles were also proposed.

  15. Charge optimized many body (COMB) potentials for Pt and Au.

    PubMed

    Antony, A C; Akhade, S A; Lu, Z; Liang, T; Janik, M J; Phillpot, S R; Sinnott, S B

    2017-06-07

    Interatomic potentials for Pt and Au are developed within the third generation charge optimized many-body (COMB3) formalism. The potentials are capable of reproducing phase order, lattice constants, and elastic constants of Pt and Au systems as experimentally measured or calculated by density functional theory. We also fit defect formation energies, surface energies and stacking fault energies for Pt and Au metals. The resulting potentials are used to map a 2D contour of the gamma surface and simulate the tensile test of 16-grain polycrystalline Pt and Au structures at 300 K. The stress-strain behaviour is investigated and the primary slip systems {1 1 1}〈1 [Formula: see text] 0〉 are identified. In addition, we perform high temperature (1800 K for Au and 2300 K for Pt) molecular dynamics simulations of 30 nm Pt and Au truncated octahedron nanoparticles and examine morphological changes of each particle. We further calculate the activation energy barrier for surface diffusion during simulations of several nanoseconds and report energies of [Formula: see text] eV for Pt and [Formula: see text] eV for Au. This initial parameterization and application of the Pt and Au potentials demonstrates a starting point for the extension of these potentials to multicomponent systems within the COMB3 framework.

  16. Ethanol electrooxidation in alkaline medium on electrochemically synthesized Co(OH)2/Au composite

    NASA Astrophysics Data System (ADS)

    Babu, Sreejith P.; Elumalai, Perumal

    2017-01-01

    Gold (Au), cobalt hydroxide (Co(OH)2) and different Co(OH)2/Au compositions were electro-deposited onto stainless steel by a potentiodynamic method from the respective metal-ion solutions. The deposits were characterized by x-ray diffraction (XRD), scanning electron microscope (SEM) and Fourier transformed infra-red spectroscopy (FT-IR). The XRD and IR data confirmed that the deposits were Au, α-Co(OH)2 or Co(OH)2/Au composites. The SEM observations confirmed that the morphology of the Au was spherical, while the α-Co(OH)2 was flakey with pores. The morphology of the Co(OH)2/Au composites consisted of highly agglomerated Au grains distributed on the Co(OH)2 matrix. The electrocatalytic activity of each of the Au, Co(OH)2 and Co(OH)2/Au-composite electrodes towards ethanol electrooxidation in an alkaline medium was investigated by cyclic voltammetry and chronoamperometry. It turned out that the Co(OH)2/Au-composite electrodes exhibited superior catalytic activity for ethanol electrooxidation compared with the pristine Au or Co(OH)2 electrodes. A peak current density as high as 25 mA cm-2 was exhibited by the Co(OH)2/ Au composite while the Au and Co(OH)2 showed only 0.9 and 13 mA cm-2, respectively. The enhanced conductivity of the Co(OH)2/Au matrix due to the presence of Au, as well as the combined catalytic activity, seemed to be responsible for the superior performance of the Co(OH)2/Au-composite electrodes.

  17. Preparation, Spectroscopic Characterization, and Frontier MO Study of the Heteronuclear Luminescent [Pt(2)Au(2)(dmb)(2)(PPh(3))(4)](PF(6))(2) Cluster (dmb = 1,8-Diisocyano-p-menthane). A Cluster with a Formal Au(0)-Au(0) Bond Encapsulated inside a "Pt(2)(dmb)(2)(2+) " Fragment.

    PubMed

    Zhang, Tianle; Drouin, Marc; Harvey, Pierre D.

    1999-11-01

    The title compound is prepared from the direct reaction of Pt(2)(dba)(3) (dba = dibenzylideneacetone) and [Au(PPh(3))(2)](PF(6)) in the presence of 1,8-diisocyano-p-methane (dmb), with Pt(2)(dmb)(2)Cl(2), [Pt(4)(dmb)(4)(PPh(3))(2)](PF(6))(2), and (PPh(3))AuCl being formed as parallel products. X-ray crystallography reveals the presence of a quasi-linear PPh(3)Au-AuPPh(3) fragment encapsulated inside a "Pt(2)(dmb)(2)(2+)" ring which is axially coordinated with two PPh(3) ligands. The d(AuAu) is 2.5977(6) Å and is indicative of a strong Au-Au single bond. The IR nu(CN) data reveal that the Pt oxidation state is I, which places the Au oxidation state at 0. The PtAu distances are 2.8422(5) and 2.8082(5) Å. The Raman-active nu(Au(2)), nu(PtAu) (b(2g) + a(g)), nu(PtP), nu(AuP), and nu(PtC) are found at 121.2, approximately 100, 85.5, 162.1, 183.1, and 457.2, and 440.9 cm(-)(1), respectively. The PtAu (0.67 mdyn Å(-)(1)) and Au(2) (1.21 mdyn Å(-)(1)) force constants (F) confirm the presence of medium PtAu and strong Au(2) bonding interactions. The absorption spectra are characterized by strong bands at lambda(max) (epsilon, M(-1) cm(-1)) at 316 (32 300), 366 (37 800), and 418 nm (21 500) and lower intensity features at 516 (2860) and 655 nm (834). The cluster is luminescent at low temperatures (solid and frozen glasses), and in the solid state at room temperature, and exhibits an emission band at approximately 875 nm, and an emission lifetime, tau(e), of 4.4 +/- 0.4 ns (solvent = butyronitrile, T = 77 K).

  18. Rational Design of Au@Pt Multibranched Nanostructures as Bifunctional Nanozymes.

    PubMed

    Wu, Jiangjiexing; Qin, Kang; Yuan, Dan; Tan, Jun; Qin, Li; Zhang, Xuejin; Wei, Hui

    2018-04-18

    One of the current challenges in nanozyme-based nanotechnology is the utilization of multifunctionalities in one material. In this regard, Au@Pt nanoparticles (NPs) with excellent enzyme-mimicking activities due to the Pt shell and unique surface plasmon resonance features from the Au core have attracted enormous research interest. However, the unique surface plasmon resonance features from the Au core have not been widely utilized. The practical problem of the optical-damping nature of Pt hinders the research into the combination of Au@Pt NPs' enzyme-mimicking properties with their surface-enhanced Raman scattering (SERS) activities. Herein, we rationally tuned the Pt amount to achieve Au@Pt NPs with simultaneous plasmonic and enzyme-mimicking activities. The results showed that Au@Pt NPs with 2.5% Pt produced the highest Raman signal in 2 min, which benefited from the remarkably accelerated catalytic oxidation of 3,3',5,5'-tetramethylbenzidine with the decorated Pt and strong electric field retained from the Au core for SERS. This study not only demonstrates the great promise of combining bimetallic nanomaterials' multiple functionalities but also provides rational guidelines to design high-performance nanozymes for potential biomedical applications.

  19. A facile approach for reducing the working voltage of Au/TiO2/Au nanostructured memristors by enhancing the local electric field

    NASA Astrophysics Data System (ADS)

    Arab Bafrani, Hamidreza; Ebrahimi, Mahdi; Bagheri Shouraki, Saeed; Moshfegh, Alireza Z.

    2018-01-01

    Memristor devices have attracted tremendous interest due to different applications ranging from nonvolatile data storage to neuromorphic computing units. Exploring the role of surface roughness of the bottom electrode (BE)/active layer interface provides useful guidelines for the optimization of the memristor switching performance. This study focuses on the effect of surface roughness of the BE electrode on the switching characteristics of Au/TiO2/Au three-layer memristor devices. An optimized wet-etching treatment condition was found to modify the surface roughness of the Au BE where the measurement results indicate that the roughness of the Au BE is affected by both duration time and solution concentrations of the wet-etching process. Then we fabricated arrays of TiO2-based nanostructured memristors sandwiched between two sets of cross-bar Au electrode lines (junction area 900 μm2). The results revealed a reduction in the working voltages in current-voltage characteristic of the device performance when increasing the surface roughness at the Au(BE)/TiO2 active layer interface. The set voltage of the device (Vset) significantly decreased from 2.26-1.93 V when we increased the interface roughness from 4.2-13.1 nm. The present work provides information for better understanding the switching mechanism of titanium-dioxide-based devices, and it can be inferred that enhancing the roughness of the Au BE/TiO2 active layer interface leads to a localized non-uniform electric field distribution that plays a vital role in reducing the energy consumption of the device.

  20. Size control of Au NPs supported by pH operation

    NASA Astrophysics Data System (ADS)

    Ichiji, Masumi; Akiba, Hiroko; Hirasawa, Izumi

    2017-07-01

    Au NPs are expected to become useful functional particles, as particle gun used for plant gene transfer and also catalysts. We have studied PSD (particle size distribution) control of Au NPs by reduction crystallization. Previous study found out importance of seeds policy and also feeding profile. In this paper, effect of pH in the reduction crystallization was investigated to clarify the possibility of Au NPs PSD control by pH operation and also their growth process. Au NPs of size range 10-600 nm were obtained in single-jet system using ascorbic acid (AsA) as a reducing agent with adjusting pH of AsA. Au NPs are found to grow in the process of nucleation, agglomeration, agglomeration growth and surface growth. Au NPs tend to grow by agglomeration and become larger size in lower pH regions, and to grow only by surface growth and become smaller size in higher pH regions.

  1. Charged-particle multiplicity and pseudorapidity distributions measured with the PHOBOS detector in Au+Au, Cu+Cu, d+Au, and p+p collisions at ultrarelativistic energies

    NASA Astrophysics Data System (ADS)

    Alver, B.; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Chai, Z.; Chetluru, V.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kotuła, J.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Li, W.; Lin, W. T.; Loizides, C.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Sedykh, I.; Skulski, W.; Smith, C. E.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Wadsworth, B.; Walters, P.; Wenger, E.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2011-02-01

    Pseudorapidity distributions of charged particles emitted in Au+Au, Cu+Cu, d+Au, and p+p collisions over a wide energy range have been measured using the PHOBOS detector at the BNL Relativistic Heavy-Ion Collider (RHIC). The centrality dependence of both the charged particle distributions and the multiplicity at midrapidity were measured. Pseudorapidity distributions of charged particles emitted with |η|<5.4, which account for between 95% and 99% of the total charged-particle emission associated with collision participants, are presented for different collision centralities. Both the midrapidity density dNch/dη and the total charged-particle multiplicity Nch are found to factorize into a product of independent functions of collision energy, sNN, and centrality given in terms of the number of nucleons participating in the collision, Npart. The total charged particle multiplicity, observed in these experiments and those at lower energies, assumes a linear dependence of (lnsNN)2 over the full range of collision energy of sNN=2.7-200 GeV.

  2. Azimuthally sensitive hanbury brown-twiss interferometry in Au + Au collisions sqrt S sub NN = 200 GeV

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Adams, J.; Adler, C.; Aggarwal, M.M.

    2004-06-30

    We present the results of a systematic study of the shape of the pion distribution in coordinate space at freeze-out in Au+Au collisions at RHIC using two-pion Hanbury Brown-Twiss (HBT) interferometry. Oscillations of the extracted HBT radii vs. emission angle indicate sources elongated perpendicular to the reaction plane. The results indicate that the pressure and expansion time of the collision system are not sufficient to completely quench its initial shape.

  3. The rational design of a Au(I) precursor for focused electron beam induced deposition.

    PubMed

    Marashdeh, Ali; Tiesma, Thiadrik; van Velzen, Niels J C; Harder, Sjoerd; Havenith, Remco W A; De Hosson, Jeff T M; van Dorp, Willem F

    2017-01-01

    Au(I) complexes are studied as precursors for focused electron beam induced processing (FEBIP). FEBIP is an advanced direct-write technique for nanometer-scale chemical synthesis. The stability and volatility of the complexes are characterized to design an improved precursor for pure Au deposition. Aurophilic interactions are found to play a key role. The short lifetime of ClAuCO in vacuum is explained by strong, destabilizing Au-Au interactions in the solid phase. While aurophilic interactions do not affect the stability of ClAuPMe 3 , they leave the complex non-volatile. Comparison of crystal structures of ClAuPMe 3 and MeAuPMe 3 shows that Au-Au interactions are much weaker or partially even absent for the latter structure. This explains its high volatility. However, MeAuPMe 3 dissociates unfavorably during FEBIP, making it an unsuitable precursor. The study shows that Me groups reduce aurophilic interactions, compared to Cl groups, which we attribute to electronic rather than steric effects. Therefore we propose MeAuCO as a potential FEBIP precursor. It is expected to have weak Au-Au interactions, making it volatile. It is stable enough to act as a volatile source for Au deposition, being stabilized by 6.5 kcal/mol. Finally, MeAuCO is likely to dissociate in a single step to pure Au.

  4. Transport characteristics in Au/pentacene/Au diodes

    NASA Astrophysics Data System (ADS)

    Hayashi, Toshiaki; Naka, Akiyoshi; Hiroki, Masanobu; Yokota, Tomoyuki; Someya, Takao; Fujiwara, Akira

    2018-03-01

    We have used scanning and transmission electron microscopes (SEM and TEM) to study the structure of a pentacene thin film grown on a Au layer with and shown that it consists of randomly oriented amorphous pentacene clusters. We have also investigated the transport properties of amorphous pentacene in a metal-semiconductor-metal (MSM) diode structure and shown that the current is logarithmically proportional to the square root of the applied voltage, which indicates that transport occurs as the result of hopping between localized sites randomly distributed in space and energy.

  5. ITO/Au/ITO sandwich structure for near-infrared plasmonics.

    PubMed

    Fang, Xu; Mak, Chee Leung; Dai, Jiyan; Li, Kan; Ye, Hui; Leung, Chi Wah

    2014-09-24

    ITO/Au/ITO trilayers with varying gold spacer layer thicknesses were deposited on glass substrates by pulsed laser deposition. Transmission electron microscopy measurements demonstrated the continuous nature of the Au layer down to 2.4 nm. XRD patterns clearly showed an enhanced crystallinity of the ITO films promoted by the insertion of the gold layer. Compared with a single layer of ITO with a carrier concentration of 7.12 × 10(20) cm(-3), the ITO/Au/ITO structure achieved an effective carrier concentration as high as 3.26 × 10(22) cm(-3). Transmittance and ellipsometry measurements showed that the optical properties of ITO/Au/ITO films were greatly influenced by the thickness of the inserted gold layer. The cross-point wavelength of the trilayer samples was reduced with increasing gold layer thickness. Importantly, the trilayer structure exhibited a reduced loss (compared with plain Au) in the near-infrared region, suggesting its potential for plasmonic applications in the near-infrared range.

  6. Synthesis, characterization, and electrochemical behavior of Au@Pd core shell nanoparticles

    NASA Astrophysics Data System (ADS)

    Wicaksono, W. P.; Ivandini, T. A.

    2017-04-01

    Au@Pd core shell nanoparticles (Au@Pd CSNPs) were successfully synthesized using a seed-mediated growth method. Firstly, a pale pink gold seed solution was used to produce a pale purple gold nanoparticles (AuNPs) core solution. Then, three series of Pd shell thickness using 20μ, 100 μL, and 500 μL of PdCl2 produced purple, brown, and deep brown of Au@Pd CSNPs respectively. A strong absorbance UV-Visible spectrum with peaks at 285 nm and 535 nm was identified for AuNPs formation. The disappearance of the peak at 535 nm was indicated the Au@Pd CSNPs formation. The electrochemical properties were examined in phosphate buffer pH 7 using cyclic voltammetry technique with boron-doped diamond (BDD) as working electrode showed a couple oxidation and reduction peak of gold at 0.67 V and at 0.33 V, respectively. The Au@Pd CNPs will be used for modification of BDD electrodes.

  7. Formation of alternating interfacial layers in Au-12Ge/Ni joints

    PubMed Central

    Lin, Shih-kang; Tsai, Ming-yueh; Tsai, Ping-chun; Hsu, Bo-hsun

    2014-01-01

    Au-Ge alloys are promising materials for high-power and high-frequency packaging, and Ni is frequently used as diffusion barriers. This study investigates interfacial reactions in Au-12Ge/Ni joints at 300°C and 400°C. For the reactions at 300°C, typical interfacial morphology was observed and the diffusion path was (Au) + (Ge)/NiGe/Ni5Ge3/Ni. However, an interesting phenomenon – the formation of (Au,Ni,Ge)/NiGe alternating layers – was observed for the reactions at 400°C. The diffusion path across the interface was liquid/(Au,Ni,Ge)/NiGe/···/(Au,Ni,Ge)/NiGe/Ni2Ge/Ni. The periodic thermodynamic instability at the NiGe/Ni2Ge interface caused the subsequent nucleation of new (Au,Ni,Ge)/NiGe pairs. The thermodynamic foundation and mechanism of formation of the alternating layers are elaborated in this paper. PMID:24690992

  8. Azimuthal anisotophy in U + U and Au + Au collisions at RHIC

    DOE PAGES

    Adamczyk, L.

    2015-11-24

    Collisions between prolate uranium nuclei are used to study how particle production and azimuthal anisotropies depend on initial geometry in heavy-ion collisions. We report the two- and four-particle cumulants, v 2{2} and v 2{4}, for charged hadrons from U+U collisions at √ SNN = 193 GeV and Au+Au collisions at √ SNN = 200 GeV. Nearly fully overlapping collisions are selected based on the energy deposited by spectators in zero degree calorimeters (ZDCs). Within this sample, the observed dependence of v 2{2} on multiplicity demonstrates that ZDC information combined with multiplicity can preferentially select different overlap configurations in U+U collisions.more » As a result, we also show that v 2 vs multiplicity can be better described by models, such as gluon saturation or quark participant models, that eliminate the dependence of the multiplicity on the number of binary nucleon-nucleon collisions.« less

  9. High Transverse Momentum Triggered Correlations over a Large Pseudorapidity Acceptance in Au+Au Collisions at sNN=200GeV

    NASA Astrophysics Data System (ADS)

    Alver, B.; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Busza, W.; Carroll, A.; Chai, Z.; Chetluru, V.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Halliwell, C.; Hamblen, J.; Hauer, M.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Li, W.; Lin, W. T.; Loizides, C.; Manly, S.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Reed, C.; Roland, C.; Roland, G.; Sagerer, J.; Seals, H.; Sedykh, I.; Smith, C. E.; Stankiewicz, M. A.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Walters, P.; Wenger, E.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wysłouch, B.

    2010-02-01

    A measurement of two-particle correlations with a high transverse momentum trigger particle (pTtrig>2.5GeV/c) is presented for Au+Au collisions at sNN=200GeV over the uniquely broad longitudinal acceptance of the PHOBOS detector (-4<Δη<2). A broadening of the away-side azimuthal correlation compared to elementary collisions is observed at all Δη. As in p+p collisions, the near side is characterized by a peak of correlated partners at small angle relative to the trigger particle. However, in central Au+Au collisions an additional correlation extended in Δη and known as the “ridge” is found to reach at least |Δη|≈4. The ridge yield is largely independent of Δη over the measured range, and it decreases towards more peripheral collisions. For the chosen pTtrig cut, the ridge yield is consistent with zero for events with less than roughly 100 participating nucleons.

  10. Self-decorated Au nanoparticles on antireflective Si pyramids with improved hydrophobicity

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Saini, C. P.; Barman, A.; Kanjilal, A., E-mail: aloke.kanjilal@snu.edu.in

    2016-04-07

    Post-deposition annealing mediated evolution of self-decorated Au nanoparticles (NPs) on chemically etched Si pyramids is presented. A distinct transformation of Si surfaces from hydrophilic to hydrophobic is initially found after chemical texturing, showing an increase in contact angle (CA) from 58° to 98° (±1°). Further improvement of hydrophobicity with CA up to ∼118° has been established after annealing a 10 nm thick Au-coated Si pyramids at 400 °C that led to the formation of Au NPs on Si facets along with self-ordering at the pyramid edges. Detailed x-ray diffraction studies suggest the evolution of crystalline Au NPs on strained Si facets. Microstructuralmore » studies, however, indicate no mixing of Au and Si atoms at the Au/Si interfaces, instead of forming Au nanocrystals at 400 °C. The improved hydrophobicity of Si pyramids, even with Au NPs can be explained in the light of a decrease in solid fractional surface area according to Wenzel's model. Moreover, a sharp drop in specular reflectance from Si pyramids in the range of 300–800 nm, especially in the ultraviolet region up to ∼0.4% is recorded in the presence of Au NPs by ultraviolet-visible spectroscopy, reflecting the possible use in photovoltaic devices with improved antireflection property.« less

  11. Highly narrow nanogap-containing Au@Au core-shell SERS nanoparticles: size-dependent Raman enhancement and applications in cancer cell imaging

    NASA Astrophysics Data System (ADS)

    Hu, Chongya; Shen, Jianlei; Yan, Juan; Zhong, Jian; Qin, Weiwei; Liu, Rui; Aldalbahi, Ali; Zuo, Xiaolei; Song, Shiping; Fan, Chunhai; He, Dannong

    2016-01-01

    Cellular imaging technologies employing metallic surface-enhanced Raman scattering (SERS) tags have gained much interest toward clinical diagnostics, but they are still suffering from poor controlled distribution of hot spots and reproducibility of SERS signals. Here, we report the fabrication and characterization of high narrow nanogap-containing Au@Au core-shell SERS nanoparticles (GCNPs) for the identification and imaging of proteins overexpressed on the surface of cancer cells. First, plasmonic nanostructures are made of gold nanoparticles (~15 nm) coated with gold shells, between which a highly narrow and uniform nanogap (~1.1 nm) is formed owing to polyA anchored on the Au cores. The well controlled distribution of Raman reporter molecules, such as 4,4'-dipyridyl (44DP) and 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB), are readily encoded in the nanogap and can generate strong, reproducible SERS signals. In addition, we have investigated the size-dependent SERS activity of GCNPs and found that with the same laser wavelength, the Raman enhancement discriminated between particle sizes. The maximum Raman enhancement was achieved at a certain threshold of particle size (~76 nm). High narrow nanogap-containing Au@Au core-shell SERS tags (GCTs) were prepared via the functionalization of hyaluronic acid (HA) on GCNPs, which recognized the CD44 receptor, a tumor-associated surface biomarker. And it was shown that GCTs have a good targeting ability to tumour cells and promising prospects for multiplex biomarker detection.Cellular imaging technologies employing metallic surface-enhanced Raman scattering (SERS) tags have gained much interest toward clinical diagnostics, but they are still suffering from poor controlled distribution of hot spots and reproducibility of SERS signals. Here, we report the fabrication and characterization of high narrow nanogap-containing Au@Au core-shell SERS nanoparticles (GCNPs) for the identification and imaging of proteins overexpressed on

  12. Corrosion resistance evaluation of Pd-free Ag-Au-Pt-Cu dental alloys.

    PubMed

    Fujita, Takeshi; Shiraishi, Takanobu; Takuma, Yasuko; Hisatsune, Kunihiro

    2011-01-01

    The corrosion resistance of nine experimental Pd-free Ag-Au-Pt-Cu dental alloys in a 0.9% NaCl solution was investigated using cyclic voltammetry (CV), optical microscopy, and scanning electron microscopy (SEM). CV measurements revealed that the breakdown potential (E(bd)) and zero current potential (E(zc)) increased with increasing Au/(Au+Ag) atomic ratio. Thus, the Au/(Au+Ag) atomic ratio, but not the Cu content, influenced the corrosion resistance of Ag-Au-Pt-Cu alloys. After the forward scan of CV, both optical and scanning electron microscope images showed that in all the experimental alloys, the matrix phase was corroded but not the second phase. From corrosion resistance viewpoint, the Ag-Au-Pt-Cu alloys seemed to be suitable for clinical application.

  13. Novel Au-TiC Catalysts for CO Oxidation and Desulfurization Processes

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rodriguez, J.A.; Liu, P.; Takahashi, Y.

    2011-05-30

    Recent articles dealing with the physical and chemical properties of novel Au-TiC catalysts are reviewed. High-resolution photoemission, scanning tunneling microscopy and first-principles periodic density-functional calculations were used to study the deposition of gold on a TiC(0 0 1) surface. Gold grows forming two-dimensional (very low coverage) and three-dimensional (medium and large coverage) islands on the carbide substrate. A positive shift in the binding energy of the C 1s core level is observed after the deposition of Au on TiC(0 0 1). The results of the density-functional calculations corroborate the formation of Au-C bonds. In general, the bond between Au andmore » the TiC(0 0 1) surface exhibits very little ionic character, but there is a substantial polarization of electrons around Au that facilitates bonding of the adatoms with electron-acceptor molecules (CO, O{sub 2}, C{sub 2}H{sub 4}, SO{sub 2}, thiophene, etc.). Experimental measurements indicate that Au/TiC(0 0 1) is a very good catalysts for the oxidation of CO, the destruction of SO{sub 2} and the hydrodesulfurization of thiophene. At temperatures below 200 K, Au/TiC(0 0 1) is able to perform the 2CO + O{sub 2} {yields} 2CO{sub 2} reaction and the full decomposition of SO{sub 2}. Furthermore, in spite of the very poor hydrodesulfurization performance of TiC(0 0 1) or Au(1 1 1), a Au/TiC(0 0 1) surface displays a hydrodesulfurization activity higher than that of conventional Ni/MoS{sub x} catalysts. Metal carbides are excellent supports for enhancing the chemical reactivity of gold. The Au/TiC system is more chemically active than systems generated by depositing Au nanoparticles on oxide surfaces.« less

  14. Novel Au-TiC Catalysts for CO Oxidation and Desulfurization Processes

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    J Rodriguez; P Liu; Y Takahashi

    2011-12-31

    Recent articles dealing with the physical and chemical properties of novel Au-TiC catalysts are reviewed. High-resolution photoemission, scanning tunneling microscopy and first-principles periodic density-functional calculations were used to study the deposition of gold on a TiC(0 0 1) surface. Gold grows forming two-dimensional (very low coverage) and three-dimensional (medium and large coverage) islands on the carbide substrate. A positive shift in the binding energy of the C 1s core level is observed after the deposition of Au on TiC(0 0 1). The results of the density-functional calculations corroborate the formation of Au-C bonds. In general, the bond between Au andmore » the TiC(0 0 1) surface exhibits very little ionic character, but there is a substantial polarization of electrons around Au that facilitates bonding of the adatoms with electron-acceptor molecules (CO, O{sub 2}, C{sub 2}H{sub 4}, SO{sub 2}, thiophene, etc.). Experimental measurements indicate that Au/TiC(0 0 1) is a very good catalysts for the oxidation of CO, the destruction of SO{sub 2} and the hydrodesulfurization of thiophene. At temperatures below 200 K, Au/TiC(0 0 1) is able to perform the 2CO + O{sub 2} {yields} 2CO{sub 2} reaction and the full decomposition of SO{sub 2}. Furthermore, in spite of the very poor hydrodesulfurization performance of TiC(0 0 1) or Au(1 1 1), a Au/TiC(0 0 1) surface displays a hydrodesulfurization activity higher than that of conventional Ni/MoS{sub x} catalysts. Metal carbides are excellent supports for enhancing the chemical reactivity of gold. The Au/TiC system is more chemically active than systems generated by depositing Au nanoparticles on oxide surfaces.« less

  15. Homoepitaxial electrodeposition on reconstructed and unreconstructed Au(100): An in-situ STM study

    NASA Astrophysics Data System (ADS)

    Al-Shakran, Mohammad; Kibler, Ludwig A.; Jacob, Timo

    2015-01-01

    A study of homoepitaxial electrodeposition on reconstructed and unreconstructed Au(100) surfaces is presented. The growth behavior has been investigated by in-situ scanning tunneling microscopy for Au(100) in contact with 0.1 M H2SO4 + 5 μM K[AuCl4]. It is shown that the initial surface structure is decisive for the emerging Au structures, giving rise to clearly different surface morphologies for electro-crystallization of Au on the unreconstructed and on the reconstructed Au(100) surface. A layer-by-layer growth is observed at more positive potentials for unreconstructed Au(100). The electrodeposition proceeds initially by the formation of Au islands followed by island coalescence due to the high mobility of surface atoms. Monatomic recessed stripes are formed as a result of the coalescence of deposited Au islands. At more negative potentials, the growth of Au proceeds strongly anisotropic on the reconstructed surface by the formation of reconstructed elongated islands.

  16. Single electron yields from semileptonic charm and bottom hadron decays in Au +Au collisions at √{sN N}=200 GeV

    NASA Astrophysics Data System (ADS)

    Adare, A.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Akimoto, R.; Alexander, J.; Alfred, M.; Aoki, K.; Apadula, N.; Aramaki, Y.; Asano, H.; Aschenauer, E. C.; Atomssa, E. T.; Awes, T. C.; Azmoun, B.; Babintsev, V.; Bai, M.; Bandara, N. S.; Bannier, B.; Barish, K. N.; Bassalleck, B.; Bathe, S.; Baublis, V.; Baumgart, S.; Bazilevsky, A.; Beaumier, M.; Beckman, S.; Belmont, R.; Berdnikov, A.; Berdnikov, Y.; Black, D.; Blau, D. S.; Bok, J. S.; Boyle, K.; Brooks, M. L.; Bryslawskyj, J.; Buesching, H.; Bumazhnov, V.; Butsyk, S.; Campbell, S.; Chen, C.-H.; Chi, C. Y.; Chiu, M.; Choi, I. J.; Choi, J. B.; Choi, S.; Choudhury, R. K.; Christiansen, P.; Chujo, T.; Chvala, O.; Cianciolo, V.; Citron, Z.; Cole, B. A.; Connors, M.; Cronin, N.; Crossette, N.; Csanád, M.; Csörgő, T.; Dairaku, S.; Danley, T. W.; Datta, A.; Daugherity, M. S.; David, G.; Deblasio, K.; Dehmelt, K.; Denisov, A.; Deshpande, A.; Desmond, E. J.; Dietzsch, O.; Ding, L.; Dion, A.; Diss, P. B.; Do, J. H.; Donadelli, M.; D'Orazio, L.; Drapier, O.; Drees, A.; Drees, K. A.; Durham, J. M.; Durum, A.; Edwards, S.; Efremenko, Y. V.; Engelmore, T.; Enokizono, A.; Esumi, S.; Eyser, K. O.; Fadem, B.; Feege, N.; Fields, D. E.; Finger, M.; Finger, M.; Fleuret, F.; Fokin, S. L.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fukao, Y.; Fusayasu, T.; Gainey, K.; Gal, C.; Gallus, P.; Garg, P.; Garishvili, A.; Garishvili, I.; Ge, H.; Giordano, F.; Glenn, A.; Gong, X.; Gonin, M.; Goto, Y.; Granier de Cassagnac, R.; Grau, N.; Greene, S. V.; Grosse Perdekamp, M.; Gu, Y.; Gunji, T.; Hachiya, T.; Haggerty, J. S.; Hahn, K. I.; Hamagaki, H.; Hamilton, H. F.; Han, S. Y.; Hanks, J.; Hasegawa, S.; Haseler, T. O. S.; Hashimoto, K.; Hayano, R.; Hayashi, S.; He, X.; Hemmick, T. K.; Hester, T.; Hill, J. C.; Hollis, R. S.; Homma, K.; Hong, B.; Horaguchi, T.; Hoshino, T.; Hotvedt, N.; Huang, J.; Huang, S.; Ichihara, T.; Iinuma, H.; Ikeda, Y.; Imai, K.; Imazu, Y.; Imrek, J.; Inaba, M.; Iordanova, A.; Isenhower, D.; Isinhue, A.; Ivanishchev, D.; Jacak, B. V.; Javani, M.; Jezghani, M.; Jia, J.; Jiang, X.; Johnson, B. M.; Joo, K. S.; Jouan, D.; Jumper, D. S.; Kamin, J.; Kanda, S.; Kang, B. H.; Kang, J. H.; Kang, J. S.; Kapustinsky, J.; Karatsu, K.; Kawall, D.; Kazantsev, A. V.; Kempel, T.; Key, J. A.; Khachatryan, V.; Khandai, P. K.; Khanzadeev, A.; Kijima, K. M.; Kim, B. I.; Kim, C.; Kim, D. J.; Kim, E.-J.; Kim, G. W.; Kim, M.; Kim, Y.-J.; Kim, Y. K.; Kimelman, B.; Kinney, E.; Kistenev, E.; Kitamura, R.; Klatsky, J.; Kleinjan, D.; Kline, P.; Koblesky, T.; Komkov, B.; Koster, J.; Kotchetkov, D.; Kotov, D.; Krizek, F.; Kurita, K.; Kurosawa, M.; Kwon, Y.; Kyle, G. S.; Lacey, R.; Lai, Y. S.; Lajoie, J. G.; Lebedev, A.; Lee, D. M.; Lee, J.; Lee, K. B.; Lee, K. S.; Lee, S.; Lee, S. H.; Lee, S. R.; Leitch, M. J.; Leite, M. A. L.; Leitgab, M.; Lewis, B.; Li, X.; Lim, S. H.; Linden Levy, L. A.; Liu, M. X.; Lynch, D.; Maguire, C. F.; Makdisi, Y. I.; Makek, M.; Manion, A.; Manko, V. I.; Mannel, E.; Maruyama, T.; McCumber, M.; McGaughey, P. L.; McGlinchey, D.; McKinney, C.; Meles, A.; Mendoza, M.; Meredith, B.; Miake, Y.; Mibe, T.; Midori, J.; Mignerey, A. C.; Milov, A.; Mishra, D. K.; Mitchell, J. T.; Miyasaka, S.; Mizuno, S.; Mohanty, A. K.; Mohapatra, S.; Montuenga, P.; Moon, H. J.; Moon, T.; Morrison, D. P.; Moskowitz, M.; Moukhanova, T. V.; Murakami, T.; Murata, J.; Mwai, A.; Nagae, T.; Nagamiya, S.; Nagashima, K.; Nagle, J. L.; Nagy, M. I.; Nakagawa, I.; Nakagomi, H.; Nakamiya, Y.; Nakamura, K. R.; Nakamura, T.; Nakano, K.; Nattrass, C.; Netrakanti, P. K.; Nihashi, M.; Niida, T.; Nishimura, S.; Nouicer, R.; Novák, T.; Novitzky, N.; Nukariya, A.; Nyanin, A. S.; Obayashi, H.; O'Brien, E.; Ogilvie, C. A.; Okada, K.; Orjuela Koop, J. D.; Osborn, J. D.; Oskarsson, A.; Ozawa, K.; Pak, R.; Pantuev, V.; Papavassiliou, V.; Park, I. H.; Park, J. S.; Park, S.; Park, S. K.; Pate, S. F.; Patel, L.; Patel, M.; Pei, H.; Peng, J.-C.; Perepelitsa, D. V.; Perera, G. D. N.; Peressounko, D. Yu.; Perry, J.; Petti, R.; Pinkenburg, C.; Pinson, R.; Pisani, R. P.; Purschke, M. L.; Qu, H.; Rak, J.; Ramson, B. J.; Ravinovich, I.; Read, K. F.; Reynolds, D.; Riabov, V.; Riabov, Y.; Richardson, E.; Rinn, T.; Riveli, N.; Roach, D.; Roche, G.; Rolnick, S. D.; Rosati, M.; Rowan, Z.; Rubin, J. G.; Ryu, M. S.; Sahlmueller, B.; Saito, N.; Sakaguchi, T.; Sako, H.; Samsonov, V.; Sarsour, M.; Sato, S.; Sawada, S.; Schaefer, B.; Schmoll, B. K.; Sedgwick, K.; Seidl, R.; Sen, A.; Seto, R.; Sett, P.; Sexton, A.; Sharma, D.; Shein, I.; Shibata, T.-A.; Shigaki, K.; Shimomura, M.; Shoji, K.; Shukla, P.; Sickles, A.; Silva, C. L.; Silvermyr, D.; Sim, K. S.; Singh, B. K.; Singh, C. P.; Singh, V.; Skolnik, M.; Slunečka, M.; Snowball, M.; Solano, S.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Sourikova, I. V.; Stankus, P. W.; Steinberg, P.; Stenlund, E.; Stepanov, M.; Ster, A.; Stoll, S. P.; Sugitate, T.; Sukhanov, A.; Sumita, T.; Sun, J.; Sziklai, J.; Takagui, E. M.; Takahara, A.; Taketani, A.; Tanaka, Y.; Taneja, S.; Tanida, K.; Tannenbaum, M. J.; Tarafdar, S.; Taranenko, A.; Tennant, E.; Tieulent, R.; Timilsina, A.; Todoroki, T.; Tomášek, M.; Torii, H.; Towell, C. L.; Towell, R.; Towell, R. S.; Tserruya, I.; Tsuchimoto, Y.; Vale, C.; van Hecke, H. W.; Vargyas, M.; Vazquez-Zambrano, E.; Veicht, A.; Velkovska, J.; Vértesi, R.; Virius, M.; Voas, B.; Vrba, V.; Vznuzdaev, E.; Wang, X. R.; Watanabe, D.; Watanabe, K.; Watanabe, Y.; Watanabe, Y. S.; Wei, F.; Whitaker, S.; White, A. S.; White, S. N.; Winter, D.; Wolin, S.; Woody, C. L.; Wysocki, M.; Xia, B.; Xue, L.; Yalcin, S.; Yamaguchi, Y. L.; Yanovich, A.; Ying, J.; Yokkaichi, S.; Yoo, J. H.; Yoon, I.; You, Z.; Younus, I.; Yu, H.; Yushmanov, I. E.; Zajc, W. A.; Zelenski, A.; Zhou, S.; Zou, L.; Phenix Collaboration

    2016-03-01

    The PHENIX Collaboration at the Relativistic Heavy Ion Collider has measured open heavy flavor production in minimum bias Au +Au collisions at √{sN N}=200 GeV via the yields of electrons from semileptonic decays of charm and bottom hadrons. Previous heavy flavor electron measurements indicated substantial modification in the momentum distribution of the parent heavy quarks owing to the quark-gluon plasma created in these collisions. For the first time, using the PHENIX silicon vertex detector to measure precision displaced tracking, the relative contributions from charm and bottom hadrons to these electrons as a function of transverse momentum are measured in Au +Au collisions. We compare the fraction of electrons from bottom hadrons to previously published results extracted from electron-hadron correlations in p +p collisions at √{sN N}=200 GeV and find the fractions to be similar within the large uncertainties on both measurements for pT>4 GeV/c . We use the bottom electron fractions in Au +Au and p +p along with the previously measured heavy flavor electron RA A to calculate the RA A for electrons from charm and bottom hadron decays separately. We find that electrons from bottom hadron decays are less suppressed than those from charm for the region 3

  17. Port-au-Prince, Haiti

    NASA Image and Video Library

    2010-01-14

    This image, produced from instrument data aboard NASA Space Shuttle Endeavour, is a perspective view of the topography of Port-au-Prince, Haiti where a magnitude 7.0 earthquake occurred on January 12, 2010.

  18. The CEA Second-Look Trial: a randomised controlled trial of carcinoembryonic antigen prompted reoperation for recurrent colorectal cancer

    PubMed Central

    Treasure, Tom; Monson, Kathryn; Fiorentino, Francesca; Russell, Christopher

    2014-01-01

    Objective In patients who have undergone a potentially curative resection of colorectal cancer, does a ‘second-look’ operation to resect recurrence, prompted by monthly monitoring of carcinoembryonic antigen, confer a survival benefit? Design A randomised controlled trial recruiting patients from 1982 to 1993 was recovered under the Restoring Invisible and Abandoned Trials (RIAT) initiative. Setting 58 hospitals in the UK. Participants From 1982 to 1993, 1447 patients were enrolled. Of these 216 met the criteria for carcinoembryonic antigen (CEA) elevation and were randomised to ‘Aggressive’ or ‘Conventional’ arms. Interventions ‘Second-look’ surgery with intention to remove any recurrence discovered. Primary outcome measure Survival. Results By February 1993, 91/108 patients had died in the ‘Aggressive arm’ and 88/108 in the ‘Conventional’ arm (relative risk=1.16, 95% CI 0.87 to 1.37). By 2011 a further 25 randomised patients had died. Kaplan-Meier analysis showed no difference in long-term survival. Conclusions The trial was closed in 1993 following a recommendation from the Data Monitoring Committee that it was highly unlikely that any survival advantage would be demonstrated for CEA prompted second-look surgery. This conclusion was confirmed by repeat analysis of survival times after 20 years. Trial registration number ISRCTN76694943. PMID:24823671

  19. Radiotherapy Improvements by Using Au Nanoparticles.

    PubMed

    Torrisi, Lorenzo

    2015-01-01

    Au nanoparticles can be prepared inside biological solutions and incorporated in special molecules for their transport through blood, drugs and proteins up to the tumour sites or directly injected in their volume when it is possible. The Au nanoparticles are biocompatible and can be accepted locally in the organism also at relatively high concentrations. The use of Au nanoparticles injected in the tumour site enhances significantly the effective atomic number of the medium, depending on the used concentration, and consequently the proton and electron energy loss and the X-ray absorption coefficient determining an increment of the local absorbed dose during radiotherapy. Traditional radiotherapy using electrons, X-rays and gamma rays, and innovative protontherapy can benefit the increment of the effective atomic number of the tissue in the presence of Au-nanoparticles embedded in the tumour volume with an adaptive up-take procedure. This method decreases the dose released to the healthy tissues permitting a better cantering of the irradiated targets and shielding the healthy tissue placed behind the tumour. The presented theoretical study approach permits to evaluate an enhancement of the radiotherapy dose of the order of 1 % using 60 MeV protons, of the order of 10% using 6 MeV electrons and of the order of 100 % using 100 keV X-ray photons. Here, we also disccused for patents relaed to the topic.

  20. Plasmonic enhancement of visible-light water splitting with Au-TiO2 composite aerogels

    NASA Astrophysics Data System (ADS)

    Desario, Paul A.; Pietron, Jeremy J.; Devantier, Devyn E.; Brintlinger, Todd H.; Stroud, Rhonda M.; Rolison, Debra R.

    2013-08-01

    We demonstrate plasmonic enhancement of visible-light-driven splitting of water at three-dimensionally (3D) networked gold-titania (Au-TiO2) aerogels. The sol-gel-derived ultraporous composite nanoarchitecture, which contains 1 to 8.5 wt% Au nanoparticles and titania in the anatase form, retains the high surface area and mesoporosity of unmodified TiO2 aerogels and maintains stable dispersion of the ~5 nm Au guests. A broad surface plasmon resonance (SPR) feature centered at ~550 nm is present for the Au-TiO2 aerogels, but not Au-free TiO2 aerogels, and spans a wide range of the visible spectrum. Gold-derived SPR in Au-TiO2 aerogels cast as films on transparent electrodes drives photoelectrochemical oxidation of aqueous hydroxide and extends the photocatalytic activity of TiO2 from the ultraviolet region to visible wavelengths exceeding 700 nm. Films of Au-TiO2 aerogels in which Au nanoparticles are deposited on pre-formed TiO2 aerogels by a deposition-precipitation method (DP Au/TiO2) also photoelectrochemically oxidize aqueous hydroxide, but less efficiently than 3D Au-TiO2, despite having an essentially identical Au nanoparticle weight fraction and size distribution. For example, 3D Au-TiO2 containing 1 wt% Au is as active as DP Au/TiO2 with 4 wt% Au. The higher photocatalytic activity of 3D Au-TiO2 derives only in part from its ability to retain the surface area and porosity of unmodified TiO2 aerogel. The magnitude of improvement indicates that in the 3D arrangement either a more accessible photoelectrochemical reaction interphase (three-phase boundary) exists or more efficient conversion of excited surface plasmons into charge carriers occurs, thereby amplifying reactivity over DP Au/TiO2. The difference in photocatalytic efficiency between the two forms of Au-TiO2 demonstrates the importance of defining the structure of Au||TiO2 interfaces within catalytic Au-TiO2 nanoarchitectures.We demonstrate plasmonic enhancement of visible-light-driven splitting of

  1. Neutron Activation and Thermoluminescent Detector Responses to a Bare Pulse of the CEA Valduc SILENE Critical Assembly

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Miller, Thomas Martin; Celik, Cihangir; McMahan, Kimberly L.

    This benchmark experiment was conducted as a joint venture between the US Department of Energy (DOE) and the French Commissariat à l'Energie Atomique (CEA). Staff at the Oak Ridge National Laboratory (ORNL) in the US and the Centre de Valduc in France planned this experiment. The experiment was conducted on October 11, 2010 in the SILENE critical assembly facility at Valduc. Several other organizations contributed to this experiment and the subsequent evaluation, including CEA Saclay, Lawrence Livermore National Laboratory (LLNL), the Y-12 National Security Complex (NSC), Babcock International Group in the United Kingdom, and Los Alamos National Laboratory (LANL). Themore » goal of this experiment was to measure neutron activation and thermoluminescent dosimeter (TLD) doses from a source similar to a fissile solution critical excursion. The resulting benchmark can be used for validation of computer codes and nuclear data libraries as required when performing analysis of criticality accident alarm systems (CAASs). A secondary goal of this experiment was to qualitatively test performance of two CAAS detectors similar to those currently and formerly in use in some US DOE facilities. The detectors tested were the CIDAS MkX and the Rocky Flats NCD-91. These detectors were being evaluated to determine whether they would alarm, so they were not expected to generate benchmark quality data.« less

  2. Au-rich filamentary behavior and associated subband gap optical absorption in hyperdoped Si

    NASA Astrophysics Data System (ADS)

    Yang, W.; Akey, A. J.; Smillie, L. A.; Mailoa, J. P.; Johnson, B. C.; McCallum, J. C.; Macdonald, D.; Buonassisi, T.; Aziz, M. J.; Williams, J. S.

    2017-12-01

    Au-hyperdoped Si, synthesized by ion implantation and pulsed laser melting, is known to exhibit a strong sub-band gap photoresponse that scales monotonically with the Au concentration. However, there is thought to be a limit to this behavior since ultrahigh Au concentrations (>1 ×1020c m-3 ) are expected to induce cellular breakdown during the rapid resolidification of Si, a process that is associated with significant lateral impurity precipitation. This work shows that the cellular morphology observed in Au-hyperdoped Si differs from that in conventional, steady-state cellular breakdown. In particular, Rutherford backscattering spectrometry combined with channeling and transmission electron microscopy revealed an inhomogeneous Au distribution and a subsurface network of Au-rich filaments, within which the Au impurities largely reside on substitutional positions in the crystalline Si lattice, at concentrations as high as ˜3 at. %. The measured substitutional Au dose, regardless of the presence of Au-rich filaments, correlates strongly with the sub-band gap optical absorptance. Upon subsequent thermal treatment, the supersaturated Au forms precipitates, while the Au substitutionality and the sub-band gap optical absorption both decrease. These results offer insight into a metastable filamentary regime in Au-hyperdoped Si that has important implications for Si-based infrared optoelectronics.

  3. Structure of the Si(111)-(5×2)-Au Surface

    NASA Astrophysics Data System (ADS)

    Abukawa, Tadashi; Nishigaya, Yoshiki

    2013-01-01

    The structure of the Si(111)-(5×2)-Au surface, one of the long-standing problems in surface science, has been solved by means of Weissenberg reflection high-energy electron diffraction. The arrangement of the Au atoms and their positions with respect to the substrate were determined from a three-dimensional Patterson function with a lateral resolution of 0.3 Å based on a large amount of diffraction data. The new structural model consists of six Au atoms in a 5×2 unit, which agrees with the recently confirmed Au coverage of 0.6 ML [I. Barke , Phys. Rev. B 79, 155301 (2009).PRBMDO1098-0121]. The model has a distinct ×2 periodicity, and includes a Au dimer. The model is also compatible with previously obtained STM images.

  4. Alternative types of molecule-decorated atomic chains in Au-CO-Au single-molecule junctions.

    PubMed

    Balogh, Zoltán; Makk, Péter; Halbritter, András

    2015-01-01

    We investigate the formation and evolution of Au-CO single-molecule break junctions. The conductance histogram exhibits two distinct molecular configurations, which are further investigated by a combined statistical analysis. According to conditional histogram and correlation analysis these molecular configurations show strong anticorrelations with each other and with pure Au monoatomic junctions and atomic chains. We identify molecular precursor configurations with somewhat higher conductance, which are formed prior to single-molecule junctions. According to detailed length analysis two distinct types of molecule-affected chain-formation processes are observed, and we compare these results to former theoretical calculations considering bridge- and atop-type molecular configurations where the latter has reduced conductance due to destructive Fano interference.

  5. Direct observation of dijets in central Au+Au collisions at sqrt[sNN]=200 GeV.

    PubMed

    Adams, J; Aggarwal, M M; Ahammed, Z; Amonett, J; Anderson, B D; Anderson, M; Arkhipkin, D; Averichev, G S; Bai, Y; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellingeri-Laurikainen, A; Bellwied, R; Bezverkhny, B I; Bhardwaj, S; Bhasin, A; Bhati, A K; Bichsel, H; Bielcik, J; Bielcikova, J; Bland, L C; Blyth, C O; Blyth, S-L; Bonner, B E; Botje, M; Bouchet, J; Brandin, A V; Bravar, A; Bystersky, M; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca Sánchez, M; Castillo, J; Catu, O; Cebra, D; Chajecki, Z; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, J H; Chen, Y; Cheng, J; Cherney, M; Chikanian, A; Choi, H A; Christie, W; Coffin, J P; Cormier, T M; Cosentino, M R; Cramer, J G; Crawford, H J; Das, D; Das, S; Daugherity, M; de Moura, M M; Dedovich, T G; Dephillips, M; Derevschikov, A A; Didenko, L; Dietel, T; Djawotho, P; Dogra, S M; Dong, W J; Dong, X; Draper, J E; Du, F; Dunin, V B; Dunlop, J C; Dutta Mazumdar, M R; Eckardt, V; Edwards, W R; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Estienne, M; Fachini, P; Fatemi, R; Fedorisin, J; Filimonov, K; Filip, P; Finch, E; Fine, V; Fisyak, Y; Fu, J; Gagliardi, C A; Gaillard, L; Gans, J; Ganti, M S; Ghazikhanian, V; Ghosh, P; Gonzalez, J E; Gorbunov, Y G; Gos, H; Grebenyuk, O; Grosnick, D; Guertin, S M; Guimaraes, K S F F; Guo, Y; Gupta, N; Gutierrez, T D; Haag, B; Hallman, T J; Hamed, A; Harris, J W; He, W; Heinz, M; Henry, T W; Hepplemann, S; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horner, M J; Huang, H Z; Huang, S L; Hughes, E W; Humanic, T J; Igo, G; Jacobs, P; Jacobs, W W; Jakl, P; Jia, F; Jiang, H; Jones, P G; Judd, E G; Kabana, S; Kang, K; Kapitan, J; Kaplan, M; Keane, D; Kechechyan, A; Khodyrev, V Yu; Kim, B C; Kiryluk, J; Kisiel, A; Kislov, E M; Klein, S R; Koetke, D D; Kollegger, T; Kopytine, M; Kotchenda, L; Kouchpil, V; Kowalik, K L; Kramer, M; Kravtsov, P; Kravtsov, V I; Krueger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; Lapointe, S; Laue, F; Lauret, J; Lebedev, A; Lednicky, R; Lee, C-H; Lehocka, S; Levine, M J; Li, C; Li, Q; Li, Y; Lin, G; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, H; Liu, J; Liu, L; Liu, Z; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; Lopez-Noriega, M; Love, W A; Lu, Y; Ludlam, T; Lynn, D; Ma, G L; Ma, J G; Ma, Y G; Magestro, D; Mahapatra, D P; Majka, R; Mangotra, L K; Manweiler, R; Margetis, S; Markert, C; Martin, L; Matis, H S; Matulenko, Yu A; McClain, C J; McShane, T S; Melnick, Yu; Meschanin, A; Miller, M L; Minaev, N G; Mioduszewski, S; Mironov, C; Mischke, A; Mishra, D K; Mitchell, J; Mohanty, B; Molnar, L; Moore, C F; Morozov, D A; Munhoz, M G; Nandi, B K; Nattrass, C; Nayak, T K; Nelson, J M; Netrakanti, P K; Nikitin, V A; Nogach, L V; Nurushev, S B; Odyniec, G; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Pachr, M; Pal, S K; Panebratsev, Y; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Peitzmann, T; Perevoztchikov, V; Perkins, C; Peryt, W; Petrov, V A; Phatak, S C; Picha, R; Planinic, M; Pluta, J; Poljak, N; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M; Potrebenikova, E; Potukuchi, B V K S; Prindle, D; Pruneau, C; Putschke, J; Rakness, G; Raniwala, R; Raniwala, S; Ray, R L; Razin, S V; Reinnarth, J; Relyea, D; Retiere, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Rose, A; Roy, C; Ruan, L; Russcher, M J; Sahoo, R; Sakrejda, I; Salur, S; Sandweiss, J; Sarsour, M; Sazhin, P S; Schambach, J; Scharenberg, R P; Schmitz, N; Schweda, K; Seger, J; Selyuzhenkov, I; Seyboth, P; Shabetai, A; Shahaliev, E; Shao, M; Sharma, M; Shen, W Q; Shimanskiy, S S; Sichtermann, E; Simon, F; Singaraju, R N; Smirnov, N; Snellings, R; Sood, G; Sorensen, P; Sowinski, J; Speltz, J; Spinka, H M; Srivastava, B; Stadnik, A; Stanislaus, T D S; Stock, R; Stolpovsky, A; Strikhanov, M; Stringfellow, B; Suaide, A A P; Sugarbaker, E; Sumbera, M; Sun, Z; Surrow, B; Swanger, M; Symons, T J M; Szanto de Toledo, A; Tai, A; Takahashi, J; Tang, A H; Tarnowsky, T; Thein, D; Thomas, J H; Timmins, A R; Timoshenko, S; Tokarev, M; Trentalange, S; Tribble, R E; Tsai, O D; Ulery, J; Ullrich, T; Underwood, D G; Van Buren, G; van der Kolk, N; van Leeuwen, M; Vander Molen, A M; Varma, R; Vasilevski, I M; Vasiliev, A N; Vernet, R; Vigdor, S E; Viyogi, Y P; Vokal, S; Voloshin, S A; Waggoner, W T; Wang, F; Wang, G; Wang, J S; Wang, X L; Wang, Y; Watson, J W; Webb, J C; Westfall, G D; Wetzler, A; Whitten, C; Wieman, H; Wissink, S W; Witt, R; Wood, J; Wu, J; Xu, N; Xu, Q H; Xu, Z; Yepes, P; Yoo, I-K; Yurevich, V I; Zhan, W; Zhang, H; Zhang, W M; Zhang, Y; Zhang, Z P; Zhao, Y; Zhong, C; Zoulkarneev, R; Zoulkarneeva, Y; Zubarev, A N; Zuo, J X

    2006-10-20

    The STAR Collaboration at the Relativistic Heavy Ion Collider reports measurements of azimuthal correlations of high transverse momentum (pT) charged hadrons in Au+Au collisions at higher pT than reported previously. As (pT) is increased, a narrow, back-to-back peak emerges above the decreasing background, providing a clear dijet signal for all collision centralities studied. Using these correlations, we perform a systematic study of dijet production and suppression in nuclear collisions, providing new constraints on the mechanisms underlying partonic energy loss in dense matter.

  6. Pion-Kaon correlations in central Au+Au collisions at square root [sNN] = 130 GeV.

    PubMed

    Adams, J; Adler, C; Aggarwal, M M; Ahammed, Z; Amonett, J; Anderson, B D; Anderson, M; Arkhipkin, D; Averichev, G S; Badyal, S K; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellwied, R; Berger, J; Bezverkhny, B I; Bhardwaj, S; Bhaskar, P; Bhati, A K; Bichsel, H; Billmeier, A; Bland, L C; Blyth, C O; Bonner, B E; Botje, M; Boucham, A; Brandin, A; Bravar, A; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca Sánchez, M; Carroll, J; Castillo, J; Castro, M; Cebra, D; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, Y; Chernenko, S P; Cherney, M; Chikanian, A; Choi, B; Christie, W; Coffin, J P; Cormier, T M; Cramer, J G; Crawford, H J; Das, D; Das, S; Derevschikov, A A; Didenko, L; Dietel, T; Dong, X; Draper, J E; Du, F; Dubey, A K; Dunin, V B; Dunlop, J C; Dutta Majumdar, M R; Eckardt, V; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Fachini, P; Faine, V; Faivre, J; Fatemi, R; Filimonov, K; Filip, P; Finch, E; Fisyak, Y; Flierl, D; Foley, K J; Fu, J; Gagliardi, C A; Ganti, M S; Gutierrez, T D; Gagunashvili, N; Gans, J; Gaudichet, L; Germain, M; Geurts, F; Ghazikhanian, V; Ghosh, P; Gonzalez, J E; Grachov, O; Grigoriev, V; Gronstal, S; Grosnick, D; Guedon, M; Guertin, S M; Gupta, A; Gushin, E; Hallman, T J; Hardtke, D; Harris, J W; Heinz, M; Henry, T W; Heppelmann, S; Herston, T; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horsley, M; Huang, H Z; Huang, S L; Humanic, T J; Igo, G; Ishihara, A; Jacobs, P; Jacobs, W W; Janik, M; Johnson, I; Jones, P G; Judd, E G; Kabana, S; Kaneta, M; Kaplan, M; Keane, D; Kiryluk, J; Kisiel, A; Klay, J; Klein, S R; Klyachko, A; Koetke, D D; Kollegger, T; Konstantinov, A S; Kopytine, M; Kotchenda, L; Kovalenko, A D; Kramer, M; Kravtsov, P; Krueger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kunde, G J; Kunz, C L; Kutuev, R Kh; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; Lansdell, C P; Lasiuk, B; Laue, F; Lauret, J; Lebedev, A; Lednický, R; Leontiev, V M; LeVine, M J; Li, C; Li, Q; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, L; Liu, Z; Liu, Q J; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; Lopez-Noriega, M; Love, W A; Ludlam, T; Lynn, D; Ma, J; Ma, Y G; Magestro, D; Mahajan, S; Mangotra, L K; Mahapatra, D P; Majka, R; Manweiler, R; Margetis, S; Markert, C; Martin, L; Marx, J; Matis, H S; Matulenko, Yu A; McShane, T S; Meissner, F; Melnick, Yu; Meschanin, A; Messer, M; Miller, M L; Milosevich, Z; Minaev, N G; Mironov, C; Mishra, D; Mitchell, J; Mohanty, B; Molnar, L; Moore, C F; Mora-Corral, M J; Morozov, V; de Moura, M M; Munhoz, M G; Nandi, B K; Nayak, S K; Nayak, T K; Nelson, J M; Nevski, P; Nikitin, V A; Nogach, L V; Norman, B; Nurushev, S B; Odyniec, G; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Paic, G; Pandey, S U; Pal, S K; Panebratsev, Y; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Perevoztchikov, V; Peryt, W; Petrov, V A; Phatak, S C; Picha, R; Planinic, M; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M; Potrebenikova, E; Potukuchi, B V K S; Prindle, D; Pruneau, C; Putschke, J; Rai, G; Rakness, G; Raniwala, R; Raniwala, S; Ravel, O; Ray, R L; Razin, S V; Reichhold, D; Reid, J G; Renault, G; Retiere, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Ruan, L J; Rykov, V; Sahoo, R; Sakrejda, I; Salur, S; Sandweiss, J; Savin, I; Schambach, J; Scharenberg, R P; Schmitz, N; Schroeder, L S; Schweda, K; Seger, J; Seliverstov, D; Seyboth, P; Shahaliev, E; Shao, M; Sharma, M; Shestermanov, K E; Shimanskii, S S; Singaraju, R N; Simon, F; Skoro, G; Smirnov, N; Snellings, R; Sood, G; Sorensen, P; Sowinski, J; Spinka, H M; Srivastava, B; Stanislaus, S; Stock, R; Stolpovsky, A; Strikhanov, M; Stringfellow, B; Struck, C; Suaide, A A P; Sugarbaker, E; Suire, C; Sumbera, M; Surrow, B; Symons, T J M; Szanto de Toledo, A; Szarwas, P; Tai, A; Takahashi, J; Tang, A H; Thein, D; Thomas, J H; Tikhomirov, V; Tokarev, M; Tonjes, M B; Trainor, T A; Trentalange, S; Tribble, R E; Trivedi, M D; Trofimov, V; Tsai, O; Ullrich, T; Underwood, D G; Van Buren, G; VanderMolen, A M; Vasiliev, A N; Vasiliev, M; Vigdor, S E; Viyogi, Y P; Voloshin, S A; Waggoner, W; Wang, F; Wang, G; Wang, X L; Wang, Z M; Ward, H; Watson, J W; Wells, R; Westfall, G D; Whitten, C; Wieman, H; Willson, R; Wissink, S W; Witt, R; Wood, J; Wu, J; Xu, N; Xu, Z; Xu, Z Z; Yakutin, A E; Yamamoto, E; Yang, J; Yepes, P; Yurevich, V I; Zanevski, Y V; Zborovský, I; Zhang, H; Zhang, H Y; Zhang, W M; Zhang, Z P; Zołnierczuk, P A; Zoulkarneev, R; Zoulkarneeva, J; Zubarev, A N

    2003-12-31

    Pion-kaon correlation functions are constructed from central Au+Au STAR data taken at sqrt[s(NN)]=130 GeV by the STAR detector at the Relativistic Heavy Ion Collider (RHIC). The results suggest that pions and kaons are not emitted at the same average space-time point. Space-momentum correlations, i.e., transverse flow, lead to a space-time emission asymmetry of pions and kaons that is consistent with the data. This result provides new independent evidence that the system created at RHIC undergoes a collective transverse expansion.

  7. Guazuma ulmifolia bark-synthesized Ag, Au and Ag/Au alloy nanoparticles: Photocatalytic potential, DNA/protein interactions, anticancer activity and toxicity against 14 species of microbial pathogens.

    PubMed

    Karthika, Viswanathan; Arumugam, Ayyakannu; Gopinath, Kasi; Kaleeswarran, Periyannan; Govindarajan, Marimuthu; Alharbi, Naiyf S; Kadaikunnan, Shine; Khaled, Jamal M; Benelli, Giovanni

    2017-02-01

    In the present study, we focused on a quick and green method to fabricate Ag, Au and Ag/Au alloy nanoparticles (NPs) using the bark extract of Guazuma ulmifolia L. Green synthesized metal NPs were characterized using different techniques, including UV-Vis spectroscopy, FT-IR, XRD, AFM and HR-TEM analyses. The production of Ag, Au and Ag/Au alloy NPs was observed monitoring color change from colorless to brown, followed by pink and dark brown, as confirmed by UV-Vis spectroscopy characteristic peaks at 436, 522 and 510nm, respectively. TEM shed light on the spherical shapes of NPs with size ranges of 10-15, 20-25 and 10-20nm. Biosynthesized NPs showed good catalytic activity reducing two organic dyes, 4-nitrophenol (4-NP) and Congo red (CR). UV-vis spectroscopy, fluorescence, circular dichroism spectroscopy and viscosity analyses were used to investigate the NP binding with calf thymus DNA. The binding constant of NPs with DNA calculated in UV-Vis absorption studies were 1.18×10 4 , 1.83×10 4 and 2.91×10 4 M -1 , respectively, indicating that NPs were able to bind DNA with variable binding affinity: Ag/Au alloy NPs>Ag NPs>Au NPs. Ag/Au alloy NPs also showed binding activity to bovine serum albumin (BSA) over the other NPs. Ag and Ag/Au alloy NPs exhibited good antimicrobial activity on 14 species of microbial pathogens. In addition, the cytotoxic effects of Ag/Au alloy NPs were studied on human cervical cancer cells (HeLa) using MTT assay. Overall, our work showed the promising potential of bark-synthesized Ag and Ag/Au alloy NPs as cheap sources to develop novel and safer photocatalytic, antimicrobial and anticancer agents. Copyright © 2017. Published by Elsevier B.V.

  8. Au38Cu1(2-PET)24 nanocluster: synthesis, enantioseparation and luminescence.

    PubMed

    Kazan, Rania; Zhang, Bei; Bürgi, Thomas

    2017-06-20

    A CuAu 38 bimetallic nanocluster was synthesized by adding a single copper atom to the Au 38 (2-PET) 24 nanocluster. The absence of Cu x Au 38-x (2-PET) 24 doped species was demonstrated by MALDI-TOF mass spectrometry. A separation of bimetallic clusters was attained for the first time where isomers of the E2 enantiomer of the Au 38 Cu 1 (2-PET) 24 adduct were successfully isolated from their parent cluster using chiral HPLC. The CD of the isolated isomers revealed a change in their electronic structure upon copper addition. The luminescence of the Au 38 Cu 1 adduct is significantly enhanced in comparison with the parent Au 38 nanocluster. The stability of the newly formed adduct is strongly dependent on the coexistence of the Au 38 nanoclusters.

  9. Plasmon enhanced water splitting mediated by hybrid bimetallic Au-Ag core-shell nanostructures.

    PubMed

    Erwin, William R; Coppola, Andrew; Zarick, Holly F; Arora, Poorva; Miller, Kevin J; Bardhan, Rizia

    2014-11-07

    In this work, we employed wet chemically synthesized bimetallic Au-Ag core-shell nanostructures (Au-AgNSs) to enhance the photocurrent density of mesoporous TiO2 for water splitting and we compared the results with monometallic Au nanoparticles (AuNPs). While Au-AgNSs incorporated photoanodes give rise to 14× enhancement in incident photon to charge carrier efficiency, AuNPs embedded photoanodes result in 6× enhancement. By varying nanoparticle concentration in the photoanodes, we observed ∼245× less Au-AgNSs are required relative to AuNPs to generate similar photocurrent enhancement for solar fuel conversion. Power-dependent measurements of Au-AgNSs and AuNPs showed a first order dependence to incident light intensity, relative to half-order dependence for TiO2 only photoanodes. This indicated that plasmonic nanostructures enhance charge carriers formed on the surface of the TiO2 which effectively participate in photochemical reactions. Our experiments and simulations suggest the enhanced near-field, far-field, and multipolar resonances of Au-AgNSs facilitating broadband absorption of solar radiation collectively gives rise to their superior performance in water splitting.

  10. Synergistic effect in an Au-Ag alloy nanocatalyst: CO oxidation.

    PubMed

    Liu, Jun-Hong; Wang, Ai-Qin; Chi, Yu-Shan; Lin, Hong-Ping; Mou, Chung-Yuan

    2005-01-13

    Au-Ag alloy nanoparticles supported on mesoporous aluminosilicate have been prepared by one-pot synthesis using hexadecyltrimethylammonium bromide (CTAB) both as a stabilizing agent for nanoparticles and as a template for the formation of mesoporous structure. The formation of Au-Ag alloy nanoparticles was confirmed by X-ray diffraction (XRD), ultraviolet-visible (UV-vis) spectroscopy, and transmission electron microscopy (TEM). Although the Au-Ag alloy nanoparticles have a larger particle size than the monometallic gold particles, they exhibited exceptionally high activity in catalysis for low-temperature CO oxidation. Even at a low temperature of 250 K, the reaction rate can reach 8.7 x 10(-6) mol.g(cat.)(-1).s(-1) at an Au/Ag molar ratio of 3/1. While neither monometallic Au@MCM-41 nor Ag@MCM-41 shows activity at this temperature, the Au-Ag alloy system shows a strongly synergistic effect in high catalytic activity. In this alloy system, the size effect is no longer a critical factor, whereas Ag is believed to play a key role in the activation of oxygen.

  11. Nanoporous Au-based chronocoulometric aptasensor for amplified detection of Pb(2+) using DNAzyme modified with Au nanoparticles.

    PubMed

    Zhang, Chen; Lai, Cui; Zeng, Guangming; Huang, Danlian; Tang, Lin; Yang, Chunping; Zhou, Yaoyu; Qin, Lei; Cheng, Min

    2016-07-15

    The authors herein described an amplified detection strategy employing nanoporous Au (NPG) and gold nanoparticles (AuNPs) to detect Pb(2+) ions in aqueous solution. The thiol modified Pb(2+)-specific DNAzyme was self-assembled onto the surface of the NPG modified electrode for hybridizing with the AuNPs labeled oligonucleotide and for forming the DNA double helix structure. Electrochemical signal, redox charge of hexaammineruthenium(III) chloride (RuHex), was measured by chronocoulometry. Taking advantage of amplification effects of the NPG electrode for increasing the reaction sites of capture probe and DNA-AuNPs complexes for bringing about the adsorption of large numbers of RuHex molecules, this electrochemical sensor could detect Pb(2+) quantitatively, in the range of 0.05-100nM, with a limit of detection as low as 0.012nM. Selectivity measurements revealed that the sensor was specific for Pb(2+) even with interference by high concentrations of other metal ions. This sensor was also used to detect Pb(2+) ions from samples of tap water, river water, and landfill leachate samples spiked with Pb(2+) ions, and the results showed good agreement with the found values determined by an atomic fluorescence spectrometer. This simple aptasensor represented a promising potential for on-site detecting Pb(2+) in drinking water. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Theoretical prediction of a new stable structure of Au28(SR)20 cluster

    NASA Astrophysics Data System (ADS)

    Sun, Xiangxiang; Wang, Pu; Xiong, Lin; Pei, Yong

    2018-07-01

    A new stable structure of Au28(SR)20 cluster is predicted, which has the same gold core as two known structures but different Au-S framework. The new Au28(SR)20 cluster is proposed to be a key link in the evolution of Au22(SR)18, Au34(SR)22 and Au40(SR)24 clusters. The four clusters belong to a homogenous Au16+6N(SR)16+2N series (N = 1-4). The relative stabilities of the new Au28 isomer structure were confirmed by density functional theory calculations including dispersion corrections (DFT-D). It is found that upon protection of certain SR ligands, the new isomer structure has lower or comparable energies to two known cluster structures.

  13. Mammalian sensitivity to elemental gold (Au?)

    USGS Publications Warehouse

    Eisler, R.

    2004-01-01

    There is increasing documentation of allergic contact dermatitis and other effects from gold jewelry, gold dental restorations, and gold implants. These effects were especially pronounced among females wearing body-piercing gold objects. One estimate of the prevalence of gold allergy worldwide is 13%, as judged by patch tests with monovalent organogold salts. Eczema of the head and neck was the most common response of individuals hypersensitive to gold, and sensitivity can last for at least several years. Ingestion of beverages containing flake gold can result in allergic-type reactions similar to those seen in gold-allergic individuals exposed to gold through dermal contact and other routes. Studies with small laboratory mammals and injected doses of colloidal gold showed increased body temperatures, accumulations in reticular cells, and dose enhancement in tumor therapy; gold implants were associated with tissue injuries. It is proposed that Au? toxicity to mammals is associated, in part, with formation of the more reactive Au+ and Au3+ species.

  14. Crystal-face-selective adsorption of Au nanoparticles onto polycrystalline diamond surfaces.

    PubMed

    Kondo, Takeshi; Aoshima, Shinsuke; Hirata, Kousuke; Honda, Kensuke; Einaga, Yasuaki; Fujishima, Akira; Kawai, Takeshi

    2008-07-15

    Crystal-face-selective adsorption of Au nanoparticles (AuNPs) was achieved on polycrystalline boron-doped diamond (BDD) surface via the self-assembly method combined with a UV/ozone treatment. To the best of our knowledge, this is the first report of crystal-face-selective adsorption on an inorganic solid surface. Hydrogen-plasma-treated BDD samples and those followed by UV/ozone treatment for 2 min or longer showed almost no adsorption of AuNP after immersion in the AuNP solution prepared by the citrate reduction method. However, the samples treated by UV/ozone for 10 s showed AuNP adsorption on their (111) facets selectively after the immersion. Moreover, the sample treated with UV/ozone for 40-60 s showed AuNP adsorption on the whole surface. These results indicate that the AuNP adsorption behavior can be controlled by UV/ozone treatment time. This phenomenon was highly reproducible and was applied to a two-step adsorption method, where AuNPs from different batches were adsorbed on the (111) and (100) surface in this order. Our findings may be of great value for the fabrication of advanced nanoparticle-based functional materials via bottom-up approaches with simple macroscale procedures.

  15. Durable electrocatalytic-activity of Pt-Au/C cathode in PEMFCs.

    PubMed

    Selvaganesh, S Vinod; Selvarani, G; Sridhar, P; Pitchumani, S; Shukla, A K

    2011-07-21

    Longevity remains as one of the central issues in the successful commercialization of polymer electrolyte membrane fuel cells (PEMFCs) and primarily hinges on the durability of the cathode. Incorporation of gold (Au) to platinum (Pt) is known to ameliorate both the electrocatalytic activity and stability of cathode in relation to pristine Pt-cathodes that are currently being used in PEMFCs. In this study, an accelerated stress test (AST) is conducted to simulate prolonged fuel-cell operating conditions by potential cycling the carbon-supported Pt-Au (Pt-Au/C) cathode. The loss in performance of PEMFC with Pt-Au/C cathode is found to be ∼10% after 7000 accelerated potential-cycles as against ∼60% for Pt/C cathode under similar conditions. These data are in conformity with the electrochemical surface-area values. PEMFC with Pt-Au/C cathode can withstand >10,000 potential cycles with very little effect on its performance. X-ray diffraction and transmission electron microscopy studies on the catalyst before and after AST suggest that incorporating Au with Pt helps mitigate aggregation of Pt particles during prolonged fuel-cell operations while X-ray photoelectron spectroscopy reflects that the metallic nature of Pt is retained in the Pt-Au catalyst during AST in comparison to Pt/C that shows a major portion of Pt to be present as oxidic platinum. Field-emission scanning electron microscopy conducted on the membrane electrode assembly before and after AST suggests that incorporating Au with Pt helps mitigating deformations in the catalyst layer. This journal is © the Owner Societies 2011

  16. Synthesis of NiAu alloy and core-shell nanoparticles in water-in-oil microemulsions

    NASA Astrophysics Data System (ADS)

    Chiu, Hsin-Kai; Chiang, I.-Chen; Chen, Dong-Hwang

    2009-07-01

    NiAu alloy nanoparticles with various Ni/Au molar ratios were synthesized by the hydrazine reduction of nickel chloride and hydrogen tetrachloroaurate in the microemulsion system. They had a face-centered cubic structure and a mean diameter of 6-13 nm, decreasing with increasing Au content. As Au nanoparticles did, they showed a characteristic absorption peak at about 520 nm but the intensity decreased with increasing Ni content. Also, they were nearly superparamagnetic, although the magnetization decreased significantly with increasing Au content. Under an external magnetic field, they could be self-organized into the parallel lines. In addition, the core-shell nanoparticles, Ni3Au1@Au, were prepared by the Au coating on the surface of Ni3Au1 alloy nanoparticles. By increasing the hydrogen tetrachloroaurate concentration for Au coating, the thickness of Au shells could be raised and led to an enhanced and red-shifted surface plasmon absorption.

  17. Au doping effects on electrical and optical properties of vanadium dioxides

    NASA Astrophysics Data System (ADS)

    Zhu, YaBin; He, Fan; Na, Jie

    2012-03-01

    Vanadium dioxides were fabricated on normal glass substrates using reactive radio frequency (RF) magnetron sputtering. The oxygen flow volume and annealed temperatures as growth parameters are systematically investigated. The electrical and optical properties of VO2 and Au:VO2 thin films with different growth conditions are discussed. The semiconductor-metal phase transition temperature decreased by ˜10°C for the sample with Au doping compared to the sample without Au doping. However, the optical transmittance of Au:VO2 thin films is much lower than that of bare VO2. These results show that Au doping has a marked effect on the electrical and optical properties.

  18. On-Chip Supercapacitor Electrode Based On Polypyrrole Deposited Into Nanoporous Au Scaffold

    NASA Astrophysics Data System (ADS)

    Lu, P.; Ohlckers, P.; Chen, X. Y.

    2016-11-01

    On-chip supercapacitors hold the potential promise for serving as the energy storage units in integrated circuit system, due to their much higher energy density in comparison with conventional dielectric capacitors, high power density and long-term cycling stability. In this study, nanoporous Au (NP-Au) film on-chip was employed as the electrode scaffold to help increase the electrolyte-accessible area for active material. Pseudo-capacitive polypyrrole (PPY) with high theoretical capacitance was deposited into the NP-Au scaffold, to construct the tailored NP-Au/PPY hybrid on-chip electrode with improved areal capacitance. Half cell test in three- electrode system revealed the improved capacitor performance of nanoporous Au supported PPY electrode, compared to the densely packed PPY nanowire film electrode on planer Au substrate (Au/PPY). The areal capacitance of 37 mF/cm2∼10 mV/s, 32 mF/cm2∼50 mV/s, 28 mF/cm2∼100 mV/s, 16 mF/cm2∼500 mV/s, were offered by NP-Au/PPY. Also, the cycling performance was enhanced via using NP-Au scaffold. The developed NP-Au/PPY on-chip electrode demonstrated herein paves a feasible pathway to employ dealloying derived porous metal as the scaffold for improving both the energy density and cycling performance for supercapacitor electrodes.

  19. Atomic and electronic structures of Si(1 1 1)-\\left(\\sqrt{\\mathbf{3}}\\times\\sqrt{\\mathbf{3}}\\right)\\text{R}\\mathbf{3}{{\\mathbf{0}}^{\\circ}} -Au and (6 × 6)-Au surfaces

    NASA Astrophysics Data System (ADS)

    Patterson, C. H.

    2015-12-01

    Si(1 1 1)-Au surfaces with around one monolayer of Au exhibit many ordered structures and structures containing disordered domain walls. Hybrid density functional theory (DFT) calculations presented here reveal the origin of these complex structures and tendency to form domain walls. The conjugate honeycomb chain trimer (CHCT) structure of the \\sqrt{3} -Au phase contains Si atoms with non-bonding surface states which can bind Au atoms in pairs in interstices of the CHCT structure and make this surface metallic. Si adatoms adsorbed on the \\sqrt{3} -Au surface induce a gapped surface through interaction with the non-bonding states. Adsorption of extra Au atoms in interstitial sites of the \\sqrt{3} -Au surface is stabilized by interaction with the non-bonding orbitals and leads to higher coverage ordered structures including the ≤ft(6× 6\\right) -Au phase. Extra Au atoms bound in interstitial sites of the \\sqrt{3} -Au surface result in top layer Si atoms with an SiAu4 butterfly wing configuration. The structure of a ≤ft(6× 6\\right) -Au phase, whose in-plane top atomic layer positions were previously determined by an electron holography technique (Grozea et al 1998 Surf. Sci. 418 32), is calculated using total energy minimization. The Patterson function for this structure is calculated and is in good agreement with data from an in-plane x-ray diffraction study (Dornisch et al 1991 Phys. Rev. B 44 11221). Filled and empty state scanning tunneling microscopy (STM) images are calculated for domain walls and the ≤ft(6× 6\\right) -Au structure. The ≤ft(6× 6\\right) -Au phase is 2D chiral and this is evident in computed and actual STM images. ≤ft(6× 6\\right) -Au and domain wall structures contain the SiAu4 motif with a butterfly wing shape. Chemical bonding within the Si-Au top layers of the \\sqrt{3} -Au and ≤ft(6× 6\\right) -Au surfaces is analyzed and an explanation for the SiAu4 motif structure is given.

  20. Centrality Evolution of pt and yt Spectra from Au-Au Collisions at √ {sNN} = 200 GeV

    NASA Astrophysics Data System (ADS)

    Trainor, Thomas A.

    A two-component analysis of spectra to pt = 12 GeV/c for identified pions and protons from 200 GeV Au-Au collisions is presented. The method is similar to an analysis of the nch dependence of pt spectra from p-p collisions at 200 GeV, but applied to Au-Au centrality dependence. The soft-component reference is a Lévy distribution on transverse mass mt. The hard-component reference is a Gaussian on transverse rapidity yt with exponential (pt power-law) tail. Deviations of data from the reference are described by hard-component ratio rAA, which generalizes nuclear modification factor RAA. The analysis suggests that centrality evolution of pion and proton spectra is dominated by changes in parton fragmentation. The structure of rAA suggests that parton energy loss produces a negative boost Δyt of a large fraction (but not all) of the minimum-bias fragment distribution, and that lower-energy partons suffer relatively less energy loss, possibly due to color screening. The analysis also suggests that the anomalous p/π ratio may be due to differences in the parton energy-loss process experienced by the two hadron species. This analysis provides no evidence for radial flow.

  1. Interaction of Au with thin ZrO2 films: influence of ZrO2 morphology on the adsorption and thermal stability of Au nanoparticles.

    PubMed

    Pan, Yonghe; Gao, Yan; Kong, Dandan; Wang, Guodong; Hou, Jianbo; Hu, Shanwei; Pan, Haibin; Zhu, Junfa

    2012-04-10

    The model catalysts of ZrO(2)-supported Au nanoparticles have been prepared by deposition of Au atoms onto the surfaces of thin ZrO(2) films with different morphologies. The adsorption and thermal stability of Au nanoparticles on thin ZrO(2) films have been investigated using synchrotron radiation photoemission spectroscopy (SRPES) and X-ray photoelectron spectroscopy (XPS). The thin ZrO(2) films were prepared by two different methods, giving rise to different morphologies. The first method utilized wet chemical impregnation to synthesize the thin ZrO(2) film through the procedure of first spin-coating a zirconium ethoxide (Zr(OC(2)H(5))(4)) precursor onto a SiO(2)/Si(100) substrate at room temperature followed by calcination at 773 K for 12 h. Scanning electron microscopy (SEM) investigations indicate that highly porous "sponge-like nanostructures" were obtained in this case. The second method was epitaxial growth of a ZrO(2)(111) film through vacuum evaporation of Zr metal onto Pt(111) in 1 × 10(-6) Torr of oxygen at 550 K followed by annealing at 1000 K. The structural analysis with low energy electron diffraction (LEED) of this film exhibits good long-range ordering. It has been found that Au forms smaller particles on the porous ZrO(2) film as compared to those on the ordered ZrO(2)(111) film at a given coverage. Thermal annealing experiments demonstrate that Au particles are more thermally stable on the porous ZrO(2) surface than on the ZrO(2)(111) surface, although on both surfaces, Au particles experience significant sintering at elevated temperatures. In addition, by annealing the surfaces to 1100 K, Au particles desorb completely from ZrO(2)(111) but not from porous ZrO(2). The enhanced thermal stability for Au on porous ZrO(2) can be attributed to the stronger interaction of the adsorbed Au with the defects and the hindered migration or coalescence resulting from the porous structures. © 2012 American Chemical Society

  2. (Tl, Au)/Si(1 1 1){\\sqrt7 \\times \\sqrt7} 2D compound: an ordered array of identical Au clusters embedded in Tl matrix

    NASA Astrophysics Data System (ADS)

    Mihalyuk, A. N.; Hsing, C. R.; Wei, C. M.; Eremeev, S. V.; Bondarenko, L. V.; Tupchaya, A. Y.; Gruznev, D. V.; Zotov, A. V.; Saranin, A. A.

    2018-01-01

    Formation of the highly-ordered \\sqrt7 × \\sqrt7 -periodicity 2D compound has been detected in the (Tl, Au)/Si(1 1 1) system as a result of Au deposition onto the Tl/Si(1 1 1) surface, its composition, structure and electronic properties have been characterized using scanning tunneling microscopy, angle-resolved photoelectron spectroscopy and density-functional-theory calculations. On the basis of these data, the structural model of the Tl-Au compound has been proposed, which adopts 12 Tl atoms and 10 Au atoms (in total, 22 atoms) per \\sqrt7 × \\sqrt7 unit cell, i.e.  ˜1.71 ML of Tl and  ˜1.43 ML of Au (in total, ˜3.14 ML). Qualitatively, the model can be visualized as consisting of truncated-pyramid-like Au clusters with a Tl atom on top, while the other Tl atoms form a double layer around the Au clusters. The (Tl, Au)/Si(1 1 1)\\sqrt7 × \\sqrt7 compound has been found to exhibit pronounced metallic properties at least down to temperatures as low as  ˜25 K, which makes it a promising object for studying electrical transport phenomena in the 2D metallic systems.

  3. Evaluation of the concrete shield compositions from the 2010 criticality accident alarm system benchmark experiments at the CEA Valduc SILENE facility

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Miller, Thomas Martin; Celik, Cihangir; Dunn, Michael E

    In October 2010, a series of benchmark experiments were conducted at the French Commissariat a l'Energie Atomique et aux Energies Alternatives (CEA) Valduc SILENE facility. These experiments were a joint effort between the United States Department of Energy Nuclear Criticality Safety Program and the CEA. The purpose of these experiments was to create three benchmarks for the verification and validation of radiation transport codes and evaluated nuclear data used in the analysis of criticality accident alarm systems. This series of experiments consisted of three single-pulsed experiments with the SILENE reactor. For the first experiment, the reactor was bare (unshielded), whereasmore » in the second and third experiments, it was shielded by lead and polyethylene, respectively. The polyethylene shield of the third experiment had a cadmium liner on its internal and external surfaces, which vertically was located near the fuel region of SILENE. During each experiment, several neutron activation foils and thermoluminescent dosimeters (TLDs) were placed around the reactor. Nearly half of the foils and TLDs had additional high-density magnetite concrete, high-density barite concrete, standard concrete, and/or BoroBond shields. CEA Saclay provided all the concrete, and the US Y-12 National Security Complex provided the BoroBond. Measurement data from the experiments were published at the 2011 International Conference on Nuclear Criticality (ICNC 2011) and the 2013 Nuclear Criticality Safety Division (NCSD 2013) topical meeting. Preliminary computational results for the first experiment were presented in the ICNC 2011 paper, which showed poor agreement between the computational results and the measured values of the foils shielded by concrete. Recently the hydrogen content, boron content, and density of these concrete shields were further investigated within the constraints of the previously available data. New computational results for the first experiment are now

  4. Au nanorods-incorporated plasmonic-enhanced inverted organic solar cells

    NASA Astrophysics Data System (ADS)

    Peng, Ling; Mei, Yang; Chen, Shu-Fen; Zhang, Yu-Pei; Hao, Jing-Yu; Deng, Ling-Ling; Huang, Wei

    2015-11-01

    The effect of Au nanorods (NRs) on optical-to-electric conversion efficiency is investigated in inverted polymer solar cells, in which Au NRs are sandwiched between two layers of ZnO. Accompanied by the optimization of thickness of ZnO covered on Au NRs, a high-power conversion efficiency of 3.60% and an enhanced short-circuit current density (JSC) of 10.87 mA/cm2 are achieved in the poly(3-hexylthiophene): [6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PC60BM)-based inverted cell and the power conversion efficiency (PCE) is enhanced by 19.6% compared with the control device. The detailed analyses of the light absorption characteristics, the simulated scattering induced by Au NRs, and the electromagnetic field around Au NRs show that the absorption improvement in the photoactive layer due to the light scattering from the longitudinal axis and the near-field increase around Au NRs induced by localized surface plasmon resonance plays a key role in enhancing the performances. Project supported by the Ministry of Science and Technology, China (Grant No. 2012CB933301), the National Natural Science Foundation of China (Grant Nos. 61274065, 51173081, 61136003, BZ2010043, 51372119, and 51172110), and the Priority Academic Program Development of Jiangsu Provincial Higher Education Institutions and Synergetic Innovation Center for Organic Electronics and Information Displays, China.

  5. Systematic study of azimuthal anisotropy in Cu + Cu and Au + Au collisions at √{sNN}=62.4 and 200 GeV

    NASA Astrophysics Data System (ADS)

    Adare, A.; Afanasiev, S.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Al-Bataineh, H.; Al-Jamel, A.; Alexander, J.; Aoki, K.; Aphecetche, L.; Armendariz, R.; Aronson, S. H.; Asai, J.; Atomssa, E. T.; Averbeck, R.; Awes, T. C.; Azmoun, B.; Babintsev, V.; Baksay, G.; Baksay, L.; Baldisseri, A.; Barish, K. N.; Barnes, P. D.; Bassalleck, B.; Bathe, S.; Batsouli, S.; Baublis, V.; Bauer, F.; Bazilevsky, A.; Belikov, S.; Bennett, R.; Berdnikov, Y.; Bickley, A. A.; Bjorndal, M. T.; Boissevain, J. G.; Borel, H.; Boyle, K.; Brooks, M. L.; Brown, D. S.; Bucher, D.; Buesching, H.; Bumazhnov, V.; Bunce, G.; Burward-Hoy, J. M.; Butsyk, S.; Campbell, S.; Chai, J.-S.; Chang, B. S.; Charvet, J.-L.; Chernichenko, S.; Chi, C. Y.; Chiba, J.; Chiu, M.; Choi, I. J.; Chujo, T.; Chung, P.; Churyn, A.; Cianciolo, V.; Cleven, C. R.; Cobigo, Y.; Cole, B. A.; Comets, M. P.; Constantin, P.; Csanád, M.; Csörgő, T.; Dahms, T.; Das, K.; David, G.; Deaton, M. B.; Dehmelt, K.; Delagrange, H.; Denisov, A.; D'Enterria, D.; Deshpande, A.; Desmond, E. J.; Dietzsch, O.; Dion, A.; Donadelli, M.; Drachenberg, J. L.; Drapier, O.; Drees, A.; Dubey, A. K.; Durum, A.; Dzhordzhadze, V.; Efremenko, Y. V.; Egdemir, J.; Ellinghaus, F.; Emam, W. S.; Enokizono, A.; En'yo, H.; Espagnon, B.; Esumi, S.; Eyser, K. O.; Fields, D. E.; Finger, M.; Finger, M.; Fleuret, F.; Fokin, S. L.; Forestier, B.; Fraenkel, Z.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fujiwara, K.; Fukao, Y.; Fung, S.-Y.; Fusayasu, T.; Gadrat, S.; Garishvili, I.; Gastineau, F.; Germain, M.; Glenn, A.; Gong, H.; Gonin, M.; Gosset, J.; Goto, Y.; Granier de Cassagnac, R.; Grau, N.; Greene, S. V.; Grosse Perdekamp, M.; Gunji, T.; Gustafsson, H.-Å.; Hachiya, T.; Hadj Henni, A.; Haegemann, C.; Haggerty, J. S.; Hagiwara, M. N.; Hamagaki, H.; Han, R.; Harada, H.; Hartouni, E. P.; Haruna, K.; Harvey, M.; Haslum, E.; Hasuko, K.; Hayano, R.; He, X.; Heffner, M.; Hemmick, T. K.; Hester, T.; Heuser, J. M.; Hiejima, H.; Hill, J. C.; Hobbs, R.; Hohlmann, M.; Holmes, M.; Holzmann, W.; Homma, K.; Hong, B.; Horaguchi, T.; Hornback, D.; Huang, S.; Hur, M. G.; Ichihara, T.; Iinuma, H.; Imai, K.; Inaba, M.; Inoue, Y.; Isenhower, D.; Isenhower, L.; Ishihara, M.; Isobe, T.; Issah, M.; Isupov, A.; Jacak, B. V.; Jia, J.; Jin, J.; Jinnouchi, O.; Johnson, B. M.; Joo, K. S.; Jouan, D.; Kajihara, F.; Kametani, S.; Kamihara, N.; Kamin, J.; Kaneta, M.; Kang, J. H.; Kanou, H.; Kawagishi, T.; Kawall, D.; Kazantsev, A. V.; Kelly, S.; Khanzadeev, A.; Kikuchi, J.; Kim, D. H.; Kim, D. J.; Kim, E.; Kim, Y.-S.; Kinney, E.; Kiss, Á.; Kistenev, E.; Kiyomichi, A.; Klay, J.; Klein-Boesing, C.; Kochenda, L.; Kochetkov, V.; Komkov, B.; Konno, M.; Kotchetkov, D.; Kozlov, A.; Král, A.; Kravitz, A.; Kroon, P. J.; Kubart, J.; Kunde, G. J.; Kurihara, N.; Kurita, K.; Kweon, M. J.; Kwon, Y.; Kyle, G. S.; Lacey, R.; Lai, Y. S.; Lajoie, J. G.; Lebedev, A.; Le Bornec, Y.; Leckey, S.; Lee, D. M.; Lee, M. K.; Lee, T.; Leitch, M. J.; Leite, M. A. L.; Lenzi, B.; Li, X.; Li, X. H.; Lim, H.; Liška, T.; Litvinenko, A.; Liu, M. X.; Love, B.; Lynch, D.; Maguire, C. F.; Makdisi, Y. I.; Malakhov, A.; Malik, M. D.; Manko, V. I.; Mao, Y.; Mašek, L.; Masui, H.; Matathias, F.; McCain, M. C.; McCumber, M.; McGaughey, P. L.; Miake, Y.; Mikeš, P.; Miki, K.; Miller, T. E.; Milov, A.; Mioduszewski, S.; Mishra, G. C.; Mishra, M.; Mitchell, J. T.; Mitrovski, M.; Morreale, A.; Morrison, D. P.; Moss, J. M.; Moukhanova, T. V.; Mukhopadhyay, D.; Murata, J.; Nagamiya, S.; Nagata, Y.; Nagle, J. L.; Naglis, M.; Nakagawa, I.; Nakamiya, Y.; Nakamura, T.; Nakano, K.; Newby, J.; Nguyen, M.; Norman, B. E.; Nouicer, R.; Nyanin, A. S.; Nystrand, J.; O'Brien, E.; Oda, S. X.; Ogilvie, C. A.; Ohnishi, H.; Ojha, I. D.; Oka, M.; Okada, K.; Omiwade, O. O.; Oskarsson, A.; Otterlund, I.; Ouchida, M.; Ozawa, K.; Pak, R.; Pal, D.; Palounek, A. P. T.; Pantuev, V.; Papavassiliou, V.; Park, J.; Park, W. J.; Pate, S. F.; Pei, H.; Peng, J.-C.; Pereira, H.; Peresedov, V.; Peressounko, D. Yu.; Pinkenburg, C.; Pisani, R. P.; Purschke, M. L.; Purwar, A. K.; Qu, H.; Rak, J.; Rakotozafindrabe, A.; Ravinovich, I.; Read, K. F.; Rembeczki, S.; Reuter, M.; Reygers, K.; Riabov, V.; Riabov, Y.; Roche, G.; Romana, A.; Rosati, M.; Rosendahl, S. S. E.; Rosnet, P.; Rukoyatkin, P.; Rykov, V. L.; Ryu, S. S.; Sahlmueller, B.; Saito, N.; Sakaguchi, T.; Sakai, S.; Sakata, H.; Samsonov, V.; Sato, H. D.; Sato, S.; Sawada, S.; Seele, J.; Seidl, R.; Semenov, V.; Seto, R.; Sharma, D.; Shea, T. K.; Shein, I.; Shevel, A.; Shibata, T.-A.; Shigaki, K.; Shimomura, M.; Shohjoh, T.; Shoji, K.; Sickles, A.; Silva, C. L.; Silvermyr, D.; Silvestre, C.; Sim, K. S.; Singh, C. P.; Singh, V.; Skutnik, S.; Slunečka, M.; Smith, W. C.; Soldatov, A.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Sourikova, I. V.; Staley, F.; Stankus, P. W.; Stenlund, E.; Stepanov, M.; Ster, A.; Stoll, S. P.; Sugitate, T.; Suire, C.; Sullivan, J. P.; Sziklai, J.; Tabaru, T.; Takagi, S.; Takagui, E. M.; Taketani, A.; Tanaka, K. H.; Tanaka, Y.; Tanida, K.; Tannenbaum, M. J.; Taranenko, A.; Tarján, P.; Thomas, T. L.; Todoroki, T.; Togawa, M.; Toia, A.; Tojo, J.; Tomášek, L.; Torii, H.; Towell, R. S.; Tram, V.-N.; Tserruya, I.; Tsuchimoto, Y.; Tuli, S. K.; Tydesjö, H.; Tyurin, N.; Vale, C.; Valle, H.; van Hecke, H. W.; Velkovska, J.; Vértesi, R.; Vinogradov, A. A.; Virius, M.; Vrba, V.; Vznuzdaev, E.; Wagner, M.; Walker, D.; Wang, X. R.; Watanabe, Y.; Wessels, J.; White, S. N.; Willis, N.; Winter, D.; Woody, C. L.; Wysocki, M.; Xie, W.; Yamaguchi, Y. L.; Yanovich, A.; Yasin, Z.; Ying, J.; Yokkaichi, S.; Young, G. R.; Younus, I.; Yushmanov, I. E.; Zajc, W. A.; Zaudtke, O.; Zhang, C.; Zhou, S.; Zimányi, J.; Zolin, L.; Phenix Collaboration

    2015-09-01

    We have studied the dependence of azimuthal anisotropy v2 for inclusive and identified charged hadrons in Au +Au and Cu +Cu collisions on collision energy, species, and centrality. The values of v2 as a function of transverse momentum pT and centrality in Au +Au collisions at √{s NN}=200 and 62.4 GeV are the same within uncertainties. However, in Cu +Cu collisions we observe a decrease in v2 values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both Au +Au and Cu +Cu collisions we find that v2 depends both on eccentricity and the number of participants, Npart. We observe that v2 divided by eccentricity (ɛ ) monotonically increases with Npart and scales as Npart1 /3. The Cu +Cu data at 62.4 GeV falls below the other scaled v2 data. For identified hadrons, v2 divided by the number of constituent quarks nq is independent of hadron species as a function of transverse kinetic energy K ET=mT-m between 0.1

  6. The AU Mic debris ring: density profile and dynamics of the dust

    NASA Astrophysics Data System (ADS)

    Augereau, Jean-Charles; Beust, Herve

    2005-10-01

    AU Mic is an M-type star surrounded by a debris disk that is viewed almost perfectly edge-on. This disk shares many common observational properties with the well-known disk orbiting Beta Pictoris but the properties of the AU Mic disk as well as the dynamics of the dust grains have not been studied in detail yet. Using a standard deprojection technique, we derive the surface density profile of the AU Mic disk from near-IR scattered light observations. We show that irrespective of the asymmetry parameter of the phase function, most of the dust emission arises from a ring-like region that extends from 30 to 45 AU. We estimate that the mean collision time-scale at these distances is of the order of a few 10000 years. Therefore, collisional evolution can happen. A striking common feature between AU Mic and Beta Pic is the surface brightness profile. In both cases, the surface brightness falls off as r^{-5} further away than 120 AU in the case of Beta Pic and 35 AU in the case of AU Mic. In the case of Beta Pic, this profile is well explained by the combined effect of collisions and radiation pressure on the smallest dust particules (e.g. Augereau et al. 2001). But this model does not apply to AU Mic because of its low luminosity (thus generating a too low radiation pressure). Conversely, we show that a standard, solar-like stellar wind generates a drag force onto dust particles that behaves much like a radiation pressure. This wind pressure appears stronger than the radiation pressure itself and this effect is considerably enhanced by the recurrent stellar flares of AU Mic. This greatly contributes to populating the extended debris disk of AU Mic and explains the similarity between the Beta Pic and AU Mic brightness profiles.

  7. The effect of metal surface passivation on the Au-InP interaction

    NASA Technical Reports Server (NTRS)

    Fatemi, Navid S.; Weizer, Victor G.

    1989-01-01

    The effect of SiO2 encapsulation on reaction rates in the Au-InP system was studied. Scanning electron microscopy and x-ray photoelectron spectroscopy were used to investigate surface and/or interface morphologies and in-depth compositional profiles. It was found that the rate of dissolution of InP into Au and subsequent phase transformations are largely dependent on the condition of the free surface of the metalization. SiO2 capping of Au is reported for the first time to suppress the Au-InP reaction rate. The Au-InP interaction is shown to be quite similar to the Au-GaAs interaction despite differences in behavior of the group-V elements.

  8. Spectroscopically forbidden infra-red emission in Au-vertical graphene hybrid nanostructures

    NASA Astrophysics Data System (ADS)

    Sivadasan, A. K.; Parida, Santanu; Ghosh, Subrata; Pandian, Ramanathaswamy; Dhara, Sandip

    2017-11-01

    Implementation of Au nanoparticles (NPs) is a subject for frontier plasmonic research due to its fascinating optical properties. Herein, the present study deals with plasmonic assisted emission properties of Au NPs-vertical graphene (VG) hybrid nanostructures. The influence of effective polarizability of Au NPs on the surface enhanced Raman scattering and luminescence properties is investigated. In addition, a remarkable infra-red emission in the hybrid nanostructures is observed and interpreted on the basis of intra-band transitions in Au NPs. The flake-like nanoporous VG structure is invoked for the generation of additional confined photons to impart additional momentum and a gradient of confined excitation energy towards initiating the intra-band transitions of Au NPs. Integrating Au plasmonic materials in three-dimensional VG nanostructures enhances the light-matter interactions. The present study provides a new adaptable plasmonic assisted pathway for optoelectronic and sensing applications.

  9. The rational design of a Au(I) precursor for focused electron beam induced deposition

    PubMed Central

    Marashdeh, Ali; Tiesma, Thiadrik; van Velzen, Niels J C; Harder, Sjoerd; Havenith, Remco W A; De Hosson, Jeff T M

    2017-01-01

    Au(I) complexes are studied as precursors for focused electron beam induced processing (FEBIP). FEBIP is an advanced direct-write technique for nanometer-scale chemical synthesis. The stability and volatility of the complexes are characterized to design an improved precursor for pure Au deposition. Aurophilic interactions are found to play a key role. The short lifetime of ClAuCO in vacuum is explained by strong, destabilizing Au–Au interactions in the solid phase. While aurophilic interactions do not affect the stability of ClAuPMe3, they leave the complex non-volatile. Comparison of crystal structures of ClAuPMe3 and MeAuPMe3 shows that Au–Au interactions are much weaker or partially even absent for the latter structure. This explains its high volatility. However, MeAuPMe3 dissociates unfavorably during FEBIP, making it an unsuitable precursor. The study shows that Me groups reduce aurophilic interactions, compared to Cl groups, which we attribute to electronic rather than steric effects. Therefore we propose MeAuCO as a potential FEBIP precursor. It is expected to have weak Au–Au interactions, making it volatile. It is stable enough to act as a volatile source for Au deposition, being stabilized by 6.5 kcal/mol. Finally, MeAuCO is likely to dissociate in a single step to pure Au. PMID:29354346

  10. Au-Pt-Au nanoraspberry structures used for mercury ion detection

    NASA Astrophysics Data System (ADS)

    Huang, Jiang-Hao; Huang, Shuai; Wen, Xiaoyan; Li, Min; Lu, Haifei

    2017-12-01

    Detection of Hg2+ with high sensitivity is of great significance in the biochemical sensing field. Quantitative of Hg2+ was realized based on the influence of Hg2+ on the UV-vis absorption performance of Au-Pt-Au core-shell nanoraspberry (APA)-rhodamine-6G (R6G) structure. First, APA sol was added into R6G indicator solution and the UV-vis absorption signal intensity of R6G was evidently promoted. The signal intensity monotonously increased as more APA sol was added. However, when HgCl2 solution was introduced, the signal intensity declined. A linear relationship between Hg2+ concentration and signal intensity at 527 nm was revealed, based on which quantitative determination of Hg2+ could be realized. Hg2+ detection sensitivity was measured to be 0.031 a.u./M with a limit of detection of 10-7 M and the response time was 20 s. A high Hg2+ detection selectivity over Cu2+, Na+, Li+, and K+ was demonstrated. Due to its simplicity and high sensitivity, the proposed method could find an extensive application prospect in the Hg2+ detection field.

  11. Study on plasmon absorption of hybrid Au-GO-GNP films for SPR sensing application

    NASA Astrophysics Data System (ADS)

    Mukhtar, Wan Maisarah; Ahmad, Farah Hayati; Samsuri, Nurul Diyanah; Murat, Noor Faezah

    2018-06-01

    This study proposed the development of hybrid Au-GO-GNP films for the enhancement of plasmon absorption in SPR sensing. Several thicknesses of Au at t=40nm, t=50nm and t=300nm were sputtered on the glass substrate. The hybridization of bilayer and trilayer films were formed by depositing GO-GNP layers and GNP-GO layers on top of various thicknesses of Au coated substrates. UV-Vis spectra analysis was conducted to characterize the plasmon absorption for each configuration. The plasmon absorption was successfully amplified by employing hybrid trilayer Au-GO-GNP with the thickness of Au film was fixed at t=50nm. It is noteworthy to highlight that the employment of bilayer and trilayer configurations are the key success to enhance the SPP excitation. Au-GNP and Au-GNP-GO results no significant outcome in comparison with Au-GO and Au-GO-GNP. A redshift of the absorbance wavelength evinces the presence of GO on Au-GO sample and GNP on Au-GO-GNP sample due to the surface reconstruction. It is important to emphasize that not all bilayer and trilayer configurations able to enhance the plasmon absorption where no significant output was obtained with the hybridization order of Au-GNP and Au-GNP-GO.

  12. Time-resolved electronic and optical properties of a thiolate-protected Au38 nanocluster

    NASA Astrophysics Data System (ADS)

    Meng, Qingguo; May, Stanley P.; Berry, Mary T.; Kilin, Dmitri S.

    2015-02-01

    Density functional theory and density matrix theory are employed to investigate the time-dependent optical and electronic properties of an Au14 nanocluster protected by six cyclic thiolate ligands, Au4(SCH3)4. The Au14[Au4(SCH3)4]6 nanocluster, i.e. Au38(SCH3)24, is equivalent to a truncated-octahedral face-centred cubic Au38 core coated by a monolayer of 24 methylthiol molecules. The electronic and optical properties, such as density of states, linear absorption spectra, nonradiative nonadiabatic dissipative electronic dynamics and radiative emission spectra were calculated and compared for the core Au14 and thiolate-protected Au38(SCH3)24 nanocluster. The main observation from computed photoluminescence for both models is a mechanism of radiative emission. Specifically, a strong contribution to light emission intensity originates from intraband transitions inside the conduction band (CB) in addition to interband LUMO → HOMO transition (HOMO: highest occupied molecular orbital and LUMO: lowest unoccupied molecular orbital). Such comparison clarifies the contributions from Au core and methylthiol ligands to the electronic and optical properties of the Au38(SCH3)24 nanocluster.

  13. Crystal structure and electronic properties of a thiolate-protected Au24 nanocluster

    NASA Astrophysics Data System (ADS)

    Das, Anindita; Li, Tao; Li, Gao; Nobusada, Katsuyuki; Zeng, Chenjie; Rosi, Nathaniel L.; Jin, Rongchao

    2014-05-01

    Solving the total structures of gold nanoclusters is of critical importance for understanding their electronic, optical and catalytic properties. Herein, we report the X-ray structure of a charge-neutral Au24(SCH2Ph-tBu)20 nanocluster. This structure features a bi-tetrahedral Au8 kernel protected by four tetrameric staple-like motifs. Electronic structure analysis is further carried out and the optical absorption spectrum is interpreted. The Au24(SCH2Ph-tBu)20, Au23(S-c-C6H11)16 and Au25(SCH2CH2Ph)18 nanoclusters constitute the first crystallographically characterized ``trio''.Solving the total structures of gold nanoclusters is of critical importance for understanding their electronic, optical and catalytic properties. Herein, we report the X-ray structure of a charge-neutral Au24(SCH2Ph-tBu)20 nanocluster. This structure features a bi-tetrahedral Au8 kernel protected by four tetrameric staple-like motifs. Electronic structure analysis is further carried out and the optical absorption spectrum is interpreted. The Au24(SCH2Ph-tBu)20, Au23(S-c-C6H11)16 and Au25(SCH2CH2Ph)18 nanoclusters constitute the first crystallographically characterized ``trio''. Electronic supplementary information (ESI) available: Experimental and supporting Fig. S1-S3. CCDC NUMBER(1000102). For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c4nr01350f

  14. Bonding properties of FCC-like Au 44 (SR) 28 clusters from X-ray absorption spectroscopy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yang, Rui; Chevrier, Daniel M.; Zeng, Chenjie

    Thiolate-protected gold clusters with precisely controlled atomic composition have recently emerged as promising candidates for a variety of applications because of their unique optical, electronic, and catalytic properties. The recent discovery of the Au44(SR)28 total structure is considered as an interesting finding in terms of the face-centered cubic (FCC)-like core structure in small gold-thiolate clusters. Herein, the unique bonding properties of Au44(SR)28 is analyzed using temperature-dependent X-ray absorption spectroscopy (XAS) measurements at the Au L3-edge and compared with other FCC-like clusters such as Au36(SR)24 and Au28(SR)20. A negative thermal expansion was detected for the Au–Au bonds of the metal coremore » (the first Au–Au shell) and was interpreted based on the unique Au core structure consisting of the Au4 units. EXAFS fitting results from Au28(SR)20, Au36(SR)24, and Au44(SR)28 show a size-dependent negative thermal expansion behavior in the first Au–Au shell, further highlighting the importance of the Au4 units in determining the Au core bonding properties and shedding light on the growth mechanism of these FCC-like Au clusters.« less

  15. Kinetically controlled synthesis of Au102(SPh)44 nanoclusters and catalytic application

    NASA Astrophysics Data System (ADS)

    Chen, Yongdong; Wang, Jin; Liu, Chao; Li, Zhimin; Li, Gao

    2016-05-01

    We here explore a kinetically controlled synthetic protocol for preparing solvent-solvable Au102(SPh)44 nanoclusters which are isolated from polydispersed gold nanoclusters by solvent extraction and size exclusion chromatography (SEC). The as-obtained Au102(SPh)44 nanoclusters are determined by matrix-assisted laser desorption ionization (MALDI) and electrospray ionization (ESI) mass spectrometry, in conjunction with UV-vis spectroscopy and thermogravimetric analysis (TGA). However, Au99(SPh)42, instead of Au102(SPh)44, is yielded when the polydispersed gold nanoclusters are etched in the presence of excess thiophenol under thermal conditions (e.g., 80 °C). Interestingly, the Au102(SPh)44 nanoclusters also can convert to Au99(SPh)42 with equivalent thiophenol ligands, evidenced by the analyses of UV-vis and MALDI mass spectrometry. Finally, the TiO2-supported Au102(SPh)44 nanocluster catalyst is investigated in the selective oxidation of sulfides into sulfoxides by the PhIO oxidant and gives rise to high catalytic activity (e.g., 80-99% conversion of R-S-R' sulfides with 96-99% selectivity for R-S(&z.dbd;O)-R' sulfoxides). The Au102(SPh)44/TiO2 catalyst also shows excellent recyclability in the sulfoxidation process.We here explore a kinetically controlled synthetic protocol for preparing solvent-solvable Au102(SPh)44 nanoclusters which are isolated from polydispersed gold nanoclusters by solvent extraction and size exclusion chromatography (SEC). The as-obtained Au102(SPh)44 nanoclusters are determined by matrix-assisted laser desorption ionization (MALDI) and electrospray ionization (ESI) mass spectrometry, in conjunction with UV-vis spectroscopy and thermogravimetric analysis (TGA). However, Au99(SPh)42, instead of Au102(SPh)44, is yielded when the polydispersed gold nanoclusters are etched in the presence of excess thiophenol under thermal conditions (e.g., 80 °C). Interestingly, the Au102(SPh)44 nanoclusters also can convert to Au99(SPh)42 with equivalent

  16. Suppression pattern of neutral pions at high transverse momentum in Au + Au collisions at sqrt[sNN]=200 GeV and constraints on medium transport coefficients.

    PubMed

    Adare, A; Afanasiev, S; Aidala, C; Ajitanand, N N; Akiba, Y; Al-Bataineh, H; Alexander, J; Al-Jamel, A; Aoki, K; Aphecetche, L; Armendariz, R; Aronson, S H; Asai, J; Atomssa, E T; Averbeck, R; Awes, T C; Azmoun, B; Babintsev, V; Baksay, G; Baksay, L; Baldisseri, A; Barish, K N; Barnes, P D; Bassalleck, B; Bathe, S; Batsouli, S; Baublis, V; Bauer, F; Bazilevsky, A; Belikov, S; Bennett, R; Berdnikov, Y; Bickley, A A; Bjorndal, M T; Boissevain, J G; Borel, H; Boyle, K; Brooks, M L; Brown, D S; Bucher, D; Buesching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, J M; Butsyk, S; Campbell, S; Chai, J-S; Chang, B S; Charvet, J-L; Chernichenko, S; Chiba, J; Chi, C Y; Chiu, M; Choi, I J; Chujo, T; Chung, P; Churyn, A; Cianciolo, V; Cleven, C R; Cobigo, Y; Cole, B A; Comets, M P; Constantin, P; Csanád, M; Csörgo, T; Dahms, T; Das, K; David, G; Deaton, M B; Dehmelt, K; Delagrange, H; Denisov, A; d'Enterria, D; Deshpande, A; Desmond, E J; Dietzsch, O; Dion, A; Donadelli, M; Drachenberg, J L; Drapier, O; Drees, A; Dubey, A K; Durum, A; Dzhordzhadze, V; Efremenko, Y V; Egdemir, J; Ellinghaus, F; Emam, W S; Enokizono, A; En'yo, H; Espagnon, B; Esumi, S; Eyser, K O; Fields, D E; Finger, M; Finger, M; Fleuret, F; Fokin, S L; Forestier, B; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fujiwara, K; Fukao, Y; Fung, S-Y; Fusayasu, T; Gadrat, S; Garishvili, I; Gastineau, F; Germain, M; Glenn, A; Gong, H; Gonin, M; Gosset, J; Goto, Y; de Cassagnac, R Granier; Grau, N; Greene, S V; Perdekamp, M Grosse; Gunji, T; Gustafsson, H-A; Hachiya, T; Henni, A Hadj; Haegemann, C; Haggerty, J S; Hagiwara, M N; Hamagaki, H; Han, R; Harada, H; Hartouni, E P; Haruna, K; Harvey, M; Haslum, E; Hasuko, K; Hayano, R; Heffner, M; Hemmick, T K; Hester, T; Heuser, J M; He, X; Hiejima, H; Hill, J C; Hobbs, R; Hohlmann, M; Holmes, M; Holzmann, W; Homma, K; Hong, B; Horaguchi, T; Hornback, D; Hur, M G; Ichihara, T; Imai, K; Imrek, J; Inaba, M; Inoue, Y; Isenhower, D; Isenhower, L; Ishihara, M; Isobe, T; Issah, M; Isupov, A; Jacak, B V; Jia, J; Jin, J; Jinnouchi, O; Johnson, B M; Joo, K S; Jouan, D; Kajihara, F; Kametani, S; Kamihara, N; Kamin, J; Kaneta, M; Kang, J H; Kanou, H; Kawagishi, T; Kawall, D; Kazantsev, A V; Kelly, S; Khanzadeev, A; Kikuchi, J; Kim, D H; Kim, D J; Kim, E; Kim, Y-S; Kinney, E; Kiss, A; Kistenev, E; Kiyomichi, A; Klay, J; Klein-Boesing, C; Kochenda, L; Kochetkov, V; Komkov, B; Konno, M; Kotchetkov, D; Kozlov, A; Král, A; Kravitz, A; Kroon, P J; Kubart, J; Kunde, G J; Kurihara, N; Kurita, K; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Lai, Y-S; Lajoie, J G; Lebedev, A; Le Bornec, Y; Leckey, S; Lee, D M; Lee, M K; Lee, T; Leitch, M J; Leite, M A L; Lenzi, B; Lim, H; Liska, T; Litvinenko, A; Liu, M X; Li, X; Li, X H; Love, B; Lynch, D; Maguire, C F; Makdisi, Y I; Malakhov, A; Malik, M D; Manko, V I; Mao, Y; Masek, L; Masui, H; Matathias, F; McCain, M C; McCumber, M; McGaughey, P L; Miake, Y; Mikes, P; Miki, K; Miller, T E; Milov, A; Mioduszewski, S; Mishra, G C; Mishra, M; Mitchell, J T; Mitrovski, M; Morreale, A; Morrison, D P; Moss, J M; Moukhanova, T V; Mukhopadhyay, D; Murata, J; Nagamiya, S; Nagata, Y; Nagle, J L; Naglis, M; Nakagawa, I; Nakamiya, Y; Nakamura, T; Nakano, K; Newby, J; Nguyen, M; Norman, B E; Nyanin, A S; Nystrand, J; O'Brien, E; Oda, S X; Ogilvie, C A; Ohnishi, H; Ojha, I D; Okada, H; Okada, K; Oka, M; Omiwade, O O; Oskarsson, A; Otterlund, I; Ouchida, M; Ozawa, K; Pak, R; Pal, D; Palounek, A P T; Pantuev, V; Papavassiliou, V; Park, J; Park, W J; Pate, S F; Pei, H; Peng, J-C; Pereira, H; Peresedov, V; Peressounko, D Yu; Pinkenburg, C; Pisani, R P; Purschke, M L; Purwar, A K; Qu, H; Rak, J; Rakotozafindrabe, A; Ravinovich, I; Read, K F; Rembeczki, S; Reuter, M; Reygers, K; Riabov, V; Riabov, Y; Roche, G; Romana, A; Rosati, M; Rosendahl, S S E; Rosnet, P; Rukoyatkin, P; Rykov, V L; Ryu, S S; Sahlmueller, B; Saito, N; Sakaguchi, T; Sakai, S; Sakata, H; Samsonov, V; Sato, H D; Sato, S; Sawada, S; Seele, J; Seidl, R; Semenov, V; Seto, R; Sharma, D; Shea, T K; Shein, I; Shevel, A; Shibata, T-A; Shigaki, K; Shimomura, M; Shohjoh, T; Shoji, K; Sickles, A; Silva, C L; Silvermyr, D; Silvestre, C; Sim, K S; Singh, C P; Singh, V; Skutnik, S; Slunecka, M; Smith, W C; Soldatov, A; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Staley, F; Stankus, P W; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Sugitate, T; Suire, C; Sullivan, J P; Sziklai, J; Tabaru, T; Takagi, S; Takagui, E M; Taketani, A; Tanaka, K H; Tanaka, Y; Tanida, K; Tannenbaum, M J; Taranenko, A; Tarján, P; Thomas, T L; Togawa, M; Toia, A; Tojo, J; Tomásek, L; Torii, H; Towell, R S; Tram, V-N; Tserruya, I; Tsuchimoto, Y; Tuli, S K; Tydesjö, H; Tyurin, N; Vale, C; Valle, H; van Hecke, H W; Velkovska, J; Vertesi, R; Vinogradov, A A; Virius, M; Vrba, V; Vznuzdaev, E; Wagner, M; Walker, D; Wang, X R; Watanabe, Y; Wessels, J; White, S N; Willis, N; Winter, D; Woody, C L; Wysocki, M; Xie, W; Yamaguchi, Y L; Yanovich, A; Yasin, Z; Ying, J; Yokkaichi, S; Young, G R; Younus, I; Yushmanov, I E; Zajc, W A; Zaudtke, O; Zhang, C; Zhou, S; Zimányi, J; Zolin, L

    2008-12-05

    For Au + Au collisions at 200 GeV, we measure neutral pion production with good statistics for transverse momentum, pT, up to 20 GeV/c. A fivefold suppression is found, which is essentially constant for 5 < pT < 20 GeV/c. Experimental uncertainties are small enough to constrain any model-dependent parametrization for the transport coefficient of the medium, e.g., q in the parton quenching model. The spectral shape is similar for all collision classes, and the suppression does not saturate in Au + Au collisions.

  17. Au nanorice assemble electrolytically into mesostars.

    PubMed

    Bardhan, Rizia; Neumann, Oara; Mirin, Nikolay; Wang, Hui; Halas, Naomi J

    2009-02-24

    Star-shaped mesotructures are formed when an aqueous suspension of Au nanorice particles, which consist of prolate hematite cores and a thin Au shell, is subjected to an electric current. The nanorice particles assemble to form hyperbranched micrometer-scale mesostars. To our knowledge, this is the first reported observation of nanoparticle assembly into larger ordered structures under the influence of an electrochemical process (H(2)O electrolysis). The assembly is accompanied by significant modifications in the morphology, dimensions, chemical composition, crystallographic structure, and optical properties of the constituent nanoparticles.

  18. Core–Shell Au@Metal-Oxide Nanoparticle Electrocatalysts for Enhanced Oxygen Evolution

    DOE PAGES

    Strickler, Alaina L.; Escudero-Escribano, Marı́a; Jaramillo, Thomas F.

    2017-09-25

    Enhanced catalysis for electrochemical oxygen evolution is essential for the efficacy of many renewable energy technologies, including water electrolyzers and metal–air batteries. Recently, Au supports have been shown to enhance the activity of many 3d transition metal-oxide thin films for the oxygen evolution reaction (OER) in alkaline media. In this paper, we translate the beneficial impact of Au supports to high surface area, device-ready core–shell nanoparticles consisting of a Au-core and a metal-oxide shell (Au@M xO y where M = Ni, Co, Fe, and CoFe). Through a systematic evaluation, we establish trends in performance and illustrate the universal activity enhancementmore » when employing the Au-core in the 3d transition metal-oxide nanoparticles. Finally, the highest activity particles, Au@CoFeO x, demonstrate an overpotential of 328 ± 3 mV over a 2 h stability test at 10 mA cm –2, illustrating that strategically coupling Au support and mixed metal-oxide effects in a core–shell nanoparticle morphology is a promising avenue to achieve device-ready, high-performance OER catalysts.« less

  19. Core–Shell Au@Metal-Oxide Nanoparticle Electrocatalysts for Enhanced Oxygen Evolution

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Strickler, Alaina L.; Escudero-Escribano, Marı́a; Jaramillo, Thomas F.

    Enhanced catalysis for electrochemical oxygen evolution is essential for the efficacy of many renewable energy technologies, including water electrolyzers and metal–air batteries. Recently, Au supports have been shown to enhance the activity of many 3d transition metal-oxide thin films for the oxygen evolution reaction (OER) in alkaline media. In this paper, we translate the beneficial impact of Au supports to high surface area, device-ready core–shell nanoparticles consisting of a Au-core and a metal-oxide shell (Au@M xO y where M = Ni, Co, Fe, and CoFe). Through a systematic evaluation, we establish trends in performance and illustrate the universal activity enhancementmore » when employing the Au-core in the 3d transition metal-oxide nanoparticles. Finally, the highest activity particles, Au@CoFeO x, demonstrate an overpotential of 328 ± 3 mV over a 2 h stability test at 10 mA cm –2, illustrating that strategically coupling Au support and mixed metal-oxide effects in a core–shell nanoparticle morphology is a promising avenue to achieve device-ready, high-performance OER catalysts.« less

  20. Structure and optical properties of silica-supported Ag-Au nanoparticles.

    PubMed

    Barreca, Davide; Gasparotto, Alberto; Maragno, Cinzia; Tondello, Eugenio; Gialanella, Stefano

    2007-07-01

    Bimetallic Ag-Au nanoparticles are synthesized by sequential deposition of Au and Ag on amorphous silica by Radio Frequency (RF)-sputtering under mild conditions. Specimens are thoroughly characterized by a multi-technique approach, aimed at investigating the system properties as a function of the Ag/Au content, as well as the evolution induced by ex-situ annealing under inert (N2) or reducing (4% H2/N2) atmospheres. The obtained results demonstrate the possibility to obtain Ag-Au alloyed nanoparticles with controllable size, shape, structure, and dispersion under mild conditions, so that the optical properties can be finely tuned as a function of the synthesis and thermal treatment conditions.

  1. Energy dependence of J/ψ production in Au + Au collisions at s N N = 39 , 62.4  and  200 GeV

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.

    The inclusive J/ψ transverse momentum spectra and nuclear modification factors are reported at mid-rapidity (|y|<1.0) in Au + Au collisions at √sNN = 39, 62.4 and 200 GeV taken by the STAR experiment. A suppression of J/ψ production, with respect to the production in p+p scaled by the number of binary nucleon–nucleon collisions, is observed in central Au + Au collisions at these three energies. No significant energy dependence of nuclear modification factors is found within uncertainties. The measured nuclear modification factors can be described by model calculations that take into account both suppression of direct J/ψ production due tomore » the color screening effect and J/ψ regeneration from recombination of uncorrelated charm–anticharm quark pairs.« less

  2. Dependence of Morphology of SiOx Nanowires on the Supersaturation of Au-Si Alloy Liquid Droplets Formed on the Au-Coated Si Substrate

    NASA Astrophysics Data System (ADS)

    Zhang, Han; Li, Ji-Xue; Jin, Ai-Zi; Zhang, Ze

    2001-11-01

    A thermodynamic theory about the dependence of morphology of SiOx nanowires on the super-saturation of alloy liquid droplets has been proposed on the basis of the vapour-liquid-solid growth mechanism and has been supported experimentally. By changing the Si concentration in the Au-Si liquid droplets formed on the Au-coated Si substrate, firework-, tulip- and bud-shaped SiOx nanowires were synthesized by a thermal evaporation method and distributed concentrically around some void defects in the Si substrate. Voids were formed underneath the surface of the Si substrate during the thermal evaporation at 850°C and resulted in the Si-concentration deficient thus different saturation of Au-Si droplets. Electron microscopy analysis showed that the nanowires had an amorphous structure and were terminated by Au-Si particles.

  3. Energy dependence of J/ψ production in Au + Au collisions at s N N = 39 , 62.4  and  200 GeV

    DOE PAGES

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; ...

    2017-05-10

    The inclusive J/ψ transverse momentum spectra and nuclear modification factors are reported at mid-rapidity (|y|<1.0) in Au + Au collisions at √sNN = 39, 62.4 and 200 GeV taken by the STAR experiment. A suppression of J/ψ production, with respect to the production in p+p scaled by the number of binary nucleon–nucleon collisions, is observed in central Au + Au collisions at these three energies. No significant energy dependence of nuclear modification factors is found within uncertainties. The measured nuclear modification factors can be described by model calculations that take into account both suppression of direct J/ψ production due tomore » the color screening effect and J/ψ regeneration from recombination of uncorrelated charm–anticharm quark pairs.« less

  4. Epitaxial CdSe-Au nanocrystal heterostructures by thermal annealing.

    PubMed

    Figuerola, Albert; van Huis, Marijn; Zanella, Marco; Genovese, Alessandro; Marras, Sergio; Falqui, Andrea; Zandbergen, Henny W; Cingolani, Roberto; Manna, Liberato

    2010-08-11

    The thermal evolution of a collection of heterogeneous CdSe-Au nanosystems (Au-decorated CdSe nanorods, networks, vertical assemblies) prepared by wet-chemical approaches was monitored in situ in the transmission electron microscope. In contrast to interfaces that are formed during kinetically controlled wet chemical synthesis, heating under vacuum conditions results in distinct and well-defined CdSe/Au interfaces, located at the CdSe polar surfaces. The high quality of these interfaces should make the heterostructures more suitable for use in nanoscale electronic devices.

  5. Low-symmetry structures of Au32Z (Z = +1, 0, -1) clusters.

    PubMed

    Jalbout, Abraham F; Contreras-Torres, Flavio F; Pérez, Luis A; Garzón, Ignacio L

    2008-01-24

    In this work, we have explored new stable structures of the Au32Z (Z = +1, 0, -1) clusters. Theoretical calculations using density functional theory within the generalized-gradient approximation were performed. Our results show that, in the anion state (Au32-), low-symmetry (disordered) structures are preferred over the caged fullerene-like isomer. In addition, the cationic cluster (Au32+) also exhibits a disordered low-symmetry structure as its lowest energy configuration, but it is much closer in energy to the fullerene-like isomer. These results, obtained at T = 0 K, indicate that disordered structures for the Au32- and Au32+ clusters may be detected not only at room temperature, as was experimentally verified for the Au32- one, but also at much lower temperatures.

  6. Annealing temperature effect on self-assembled Au droplets on Si (111).

    PubMed

    Sui, Mao; Li, Ming-Yu; Kim, Eun-Soo; Lee, Jihoon

    2013-12-13

    We investigate the effect of annealing temperature on self-assembled Au droplets on Si (111). The annealing temperature is systematically varied while fixing other growth parameters such as deposition amount and annealing duration clearly to observe the annealing temperature effect. Self-assembled Au droplets are fabricated by annealing from 50°C to 850°C with 2-nm Au deposition for 30 s. With increased annealing temperatures, Au droplets show gradually increased height and diameter while the density of droplets progressively decreases. Self-assembled Au droplets with fine uniformity can be fabricated between 550°C and 800°C. While Au droplets become much larger with increased deposition amount, the extended annealing duration only mildly affects droplet size and density. The results are systematically analyzed with cross-sectional line profiles, Fourier filter transform power spectra, height histogram, surface area ratio, and size and density plots. This study can provide an aid point for the fabrication of nanowires on Si (111).

  7. A superconducting battery material: Lithium gold boride (LiAu3B)

    NASA Astrophysics Data System (ADS)

    Aydin, Sezgin; Şimşek, Mehmet

    2018-04-01

    The superconducting and potential cathode material properties of ternary boride of LiAu3B have been investigated by density functional first principles. The Li-concentration effects on the actual electronic and structural properties, namely the properties of LixAu9B3 (x = 0, 1, 2) sub-systems are studied. It is remarkably shown that the existence of Li-atoms has no considerable effect on the structural properties of Au-B skeleton in LiAu3B. Then, it can be offered as a potential cathode material for Li-ion batteries with the very small volume deviation of 0.42%, and the suitable average open circuit voltage of ∼1.30 V. Furthermore, the vibrational and superconducting properties such as electron-phonon coupling constant (λ) and critical temperature (Tc) of LiAu3B are studied. The calculated results suggest that LiAu3B should be a superconductor with Tc ∼5.8 K, also.

  8. Evaluation d'une approche pedagogique respectant les facons d'apprendre des filles en sciences et en TIC en 9e annee au Nouveau-Brunswick

    NASA Astrophysics Data System (ADS)

    Lirette-Pitre, Nicole T.

    2009-07-01

    La reussite scolaire des filles les amene de plus en plus a poursuivre une formation postsecondaire et a exercer des professions qui demandent un haut niveau de connaissances et d'expertise scientifique. Toutefois, les filles demeurent toujours tres peu nombreuses a envisager une carriere en sciences (chimie et physique), en ingenierie ou en TIC (technologie d'information et de la communication), soit une carriere reliee a la nouvelle economie. Pour plusieurs filles, les sciences et les TIC ne sont pas des matieres scolaires qu'elles trouvent interessantes meme si elles y reussissent tres bien. Ces filles admettent que leurs experiences d'apprentissage en sciences et en TIC ne leur ont pas permis de developper un interet ni de se sentir confiante en leurs habiletes a reussir dans ces matieres. Par consequent, peu de filles choisissent de poursuivre leurs etudes postsecondaires dans ces disciplines. La theorie sociocognitive du choix carriere a ete choisie comme modele theorique pour mieux comprendre quelles variables entrent en jeu lorsque les filles choisissent leur carriere. Notre etude a pour objet la conception et l'evaluation de l'efficacite d'un materiel pedagogique concu specifiquement pour ameliorer les experiences d'apprentissage en sciences et en TIC des filles de 9e annee au Nouveau-Brunswick. L'approche pedagogique privilegiee dans notre materiel a mis en oeuvre des strategies pedagogiques issues des meilleures pratiques que nous avons identifiees et qui visaient particulierement l'augmentation du sentiment d'auto-efficacite et de l'interet des filles pour ces disciplines. Ce materiel disponible par Internet a l'adresse http://www.umoncton.ca/lirettn/scientic est directement en lien avec le programme d'etudes en sciences de la nature de 9e annee du Nouveau-Brunswick. L'evaluation de l'efficacite de notre materiel pedagogique a ete faite selon deux grandes etapes methodologiques: 1) l'evaluation de l'utilisabilite et de la convivialite du materiel et 2

  9. Evaluation of the CEAS model for barley yields in North Dakota and Minnesota

    NASA Technical Reports Server (NTRS)

    Barnett, T. L. (Principal Investigator)

    1981-01-01

    The CEAS yield model is based upon multiple regression analysis at the CRD and state levels. For the historical time series, yield is regressed on a set of variables derived from monthly mean temperature and monthly precipitation. Technological trend is represented by piecewise linear and/or quadriatic functions of year. Indicators of yield reliability obtained from a ten-year bootstrap test (1970-79) demonstrated that biases are small and performance as indicated by the root mean square errors are acceptable for intended application, however, model response for individual years particularly unusual years, is not very reliable and shows some large errors. The model is objective, adequate, timely, simple and not costly. It considers scientific knowledge on a broad scale but not in detail, and does not provide a good current measure of modeled yield reliability.

  10. Direct observation of interfacial Au atoms on TiO₂ in three dimensions.

    PubMed

    Gao, Wenpei; Sivaramakrishnan, Shankar; Wen, Jianguo; Zuo, Jian-Min

    2015-04-08

    Interfacial atoms, which result from interactions between the metal nanoparticles and support, have a large impact on the physical and chemical properties of nanoparticles. However, they are difficult to observe; the lack of knowledge has been a major obstacle toward unraveling their role in chemical transformations. Here we report conclusive evidence of interfacial Au atoms formed on the rutile (TiO2) (110) surfaces by activation using high-temperature (∼500 °C) annealing in air. Three-dimensional imaging was performed using depth-sectioning enabled by aberration-corrected scanning transmission electron microscopy. Results show that the interface between Au nanocrystals and TiO2 (110) surfaces consists of a single atomic layer with Au atoms embedded inside Ti-O. The number of interfacial Au atoms is estimated from ∼1-8 in an interfacial atomic column. Direct impact of interfacial Au atoms is observed on an enhanced Au-TiO2 interaction and the reduction of surface TiO2; both are critical to Au catalysis.

  11. Surface-enhanced Raman spectroscopy with Au-nanoparticle substrate fabricated by using femtosecond pulse.

    PubMed

    Zhang, Wending; Li, Cheng; Gao, Kun; Lu, Fanfan; Liu, Min; Li, Xin; Zhang, Lu; Mao, Dong; Gao, Feng; Huang, Ligang; Mei, Ting; Zhao, Jianlin

    2018-05-18

    Au-nanoparticle (Au-NP) substrates for surface-enhanced Raman spectroscopy (SERS) were fabricated by grid-like scanning a Au-film using a femtosecond pulse. The Au-NPs were directly deposited on the Au-film surface due to the scanning process. The experimentally obtained Au-NPs presented local surface plasmon resonance effect in the visible spectral range, as verified by finite difference time domain simulations and measured reflection spectrum. The SERS experiment using the Au-NP substrates exhibited high activity and excellent substrate reproducibility and stability, and a clearly present Raman spectra of target analytes, e.g. Rhodamine-6G, Rhodamine-B and Malachite green, with concentrations down to 10 -9 M. This work presents an effective approach to producing Au-NP SERS substrates with advantages in activity, reproducibility and stability, which could be used in a wide variety of practical applications for trace amount detection.

  12. Surface-enhanced Raman spectroscopy with Au-nanoparticle substrate fabricated by using femtosecond pulse

    NASA Astrophysics Data System (ADS)

    Zhang, Wending; Li, Cheng; Gao, Kun; Lu, Fanfan; Liu, Min; Li, Xin; Zhang, Lu; Mao, Dong; Gao, Feng; Huang, Ligang; Mei, Ting; Zhao, Jianlin

    2018-05-01

    Au-nanoparticle (Au-NP) substrates for surface-enhanced Raman spectroscopy (SERS) were fabricated by grid-like scanning a Au-film using a femtosecond pulse. The Au-NPs were directly deposited on the Au-film surface due to the scanning process. The experimentally obtained Au-NPs presented local surface plasmon resonance effect in the visible spectral range, as verified by finite difference time domain simulations and measured reflection spectrum. The SERS experiment using the Au-NP substrates exhibited high activity and excellent substrate reproducibility and stability, and a clearly present Raman spectra of target analytes, e.g. Rhodamine-6G, Rhodamine-B and Malachite green, with concentrations down to 10‑9 M. This work presents an effective approach to producing Au-NP SERS substrates with advantages in activity, reproducibility and stability, which could be used in a wide variety of practical applications for trace amount detection.

  13. Antibacterial Au nanostructured surfaces

    NASA Astrophysics Data System (ADS)

    Wu, Songmei; Zuber, Flavia; Brugger, Juergen; Maniura-Weber, Katharina; Ren, Qun

    2016-01-01

    We present here a technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It was found that all the Au nanostructures, regardless their shapes, exhibited similar excellent antibacterial properties. A comparison of live cells attached to nanotopographic surfaces showed that the number of live S. aureus cells was <1% of that from flat and rough reference surfaces. Our micro/nanofabrication process is a scalable approach based on cost-efficient self-organization and provides potential for further developing functional surfaces to study the behavior of microbes on nanoscale topographies.We present here a technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It

  14. Energy levels, wavelengths, and transition rates of multipole transitions (E1, E2, M1, M2) in Au{sup 67+} and Au{sup 66+} ions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hamasha, Safeia, E-mail: safeia@hu.edu.jo

    2013-11-15

    The fully relativistic configuration interaction method of the FAC code is used to calculate atomic data for multipole transitions in Mg-like Au (Au{sup 67+}) and Al-like Au (Au{sup 66+}) ions. Generated atomic data are important in the modeling of M-shell spectra for heavy Au ions and Au plasma diagnostics. Energy levels, oscillator strengths and transition rates are calculated for electric-dipole (E1), electric quadrupole (E2), magnetic dipole (M1), and magnetic quadrupole (M2) for transitions between excited and ground states 3l−nl{sup ′}, such that n=4,5,6,7. The local central potential is derived using the Dirac–Fock–Slater method. Correlation effects to all orders are consideredmore » by the configuration interaction expansion. All relativistic effects are included in the calculations. Calculated energy levels are compared against published values that were calculated using the multi-reference many body perturbation theory, which includes higher order QED effects. Favorable agreement was observed, with less than 0.15% difference.« less

  15. Dielectron azimuthal anisotropy at mid-rapidity in Au + Au collisions at s N N = 200 GeV

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.

    We report on the first measurement of the azimuthal anisotropy (v2) of dielectrons (e+e- pairs) at mid-rapidity from √sNN=200 GeV Au + Au collisions with the STAR detector at the Relativistic Heavy Ion Collider (RHIC), presented as a function of transverse momentum (pT) for different invariant-mass regions. In the mass region Mee<1.1 GeV/c2 the dielectron v2 measurements are found to be consistent with expectations from π0,η,ω, and Φ decay contributions. In the mass region 1.1

  16. Elliptic flow due to charged hadrons for Au+Au collisions at RHIC energy 62.4 GeV

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kumar, Somani Ajit, E-mail: ajit.somani@gmail.com; Sudhir, Bhardwaj; Ashish, Agnihotri

    Elliptic flow is an important observable in search of Quark Gluon Plasma. The elliptic flow parameter dependence on centrality due to charged hadrons were studied using events generated by event generator AMPT at center of mass energy of 62.4 GeV per nucleon pair for Au+Au collisions. This study performed for pseudorapidity range from −0.35 to 0.35 and transverse momentum bins p{sub t} = 0.2 to 1 GeV/c and 1 to 2 GeV/c. We compared the results obtained from simulated data and RHIC-PHENIX data.

  17. Systematic study of azimuthal anisotropy in Cu + Cu and Au + Au collisions at √s NN = 62.4 and 200 GeV

    DOE PAGES

    Adare, A.

    2015-09-23

    We have studied the dependence of azimuthal anisotropy v 2 for inclusive and identified charged hadrons in Au+Au and Cu+Cu collisions on collision energy, species, and centrality. The values of v 2 as a function of transverse momentum pT and centrality in Au+Au collisions at √s NN=200 and 62.4 GeV are the same within uncertainties. However, in Cu+Cu collisions we observe a decrease in v 2 values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both Au+Au and Cu+Cu collisions we find that v 2 dependsmore » both on eccentricity and the number of participants, N part. We observe that v 2 divided by eccentricity (ε) monotonically increases with N part and scales as N 1/3 part. Thus, the Cu+Cu data at 62.4 GeV falls below the other scaled v 2 data. For identified hadrons, v 2 divided by the number of constituent quarks nq is independent of hadron species as a function of transverse kinetic energy KE T=m T–m between 0.1T/n q<1 GeV. Combining all of the above scaling and normalizations, we observe a near-universal scaling, with the exception of the Cu+Cu data at 62.4 GeV, of v 2/(n q∙ε∙N 1/3 part) vs KE T/n q for all measured particles.« less

  18. Extraordinary epitaxial alignment of graphene islands on Au(111)

    NASA Astrophysics Data System (ADS)

    Wofford, Joseph M.; Starodub, Elena; Walter, Andrew L.; Nie, Shu; Bostwick, Aaron; Bartelt, Norman C.; Thürmer, Konrad; Rotenberg, Eli; McCarty, Kevin F.; Dubon, Oscar D.

    2012-05-01

    Pristine, single-crystalline graphene displays a unique collection of remarkable electronic properties that arise from its two-dimensional, honeycomb structure. Using in situ low-energy electron microscopy, we show that when deposited on the (111) surface of Au carbon forms such a structure. The resulting monolayer, epitaxial film is formed by the coalescence of dendritic graphene islands that nucleate at a high density. Over 95% of these islands can be identically aligned with respect to each other and to the Au substrate. Remarkably, the dominant island orientation is not the better lattice-matched 30° rotated orientation but instead one in which the graphene [01] and Au [011] in-plane directions are parallel. The epitaxial graphene film is only weakly coupled to the Au surface, which maintains its reconstruction under the slightly p-type doped graphene. The linear electronic dispersion characteristic of free-standing graphene is retained regardless of orientation. That a weakly interacting, non-lattice matched substrate is able to lock graphene into a particular orientation is surprising. This ability, however, makes Au(111) a promising substrate for the growth of single crystalline graphene films.

  19. Acetanilide mediated reversible assembly and disassembly of Au nanoparticles.

    PubMed

    Murugadoss, A; Kar, Manoranjan; Chattopadhyay, Arun

    2008-08-01

    Herein we report the generation of Au nanoparticles (NPs) by sparingly soluble acetanilide in water. We also report the formation of linear chain-like superstructures of self-assembled Au NPs, in the presence of excess acetanilide. This was achieved in two different ways. In the first method, acetanilide was added, with increasing concentration, into aqueous HAuCl(4) to produce Au NPs as well as for the formation of assembly, which varied according to the concentration of acetanilide. The other route involved formation of spherical Au NPs at the lowest concentration of acetanilide, which was followed by the formation of assembly of various lengths upon further addition of variable amount of acetanilide. The assemblies were stable in aqueous solution for days with characteristic UV-vis absorption spectra consisting of two peaks. While the wavelength of the first peak remained the same, the position of the second peak changed to longer wavelength with increasing acetanilide concentration. Interestingly, the linear chain-like arrays could be broken into individual particles by first dilution of the solution concentration followed by treatment with ultrasonic waves. The individual Au NPs again formed linear chain-like arrays upon addition of excess acetanilide.

  20. Ultrathin Au-Alloy Nanowires at the Liquid-Liquid Interface.

    PubMed

    Chatterjee, Dipanwita; Shetty, Shwetha; Müller-Caspary, Knut; Grieb, Tim; Krause, Florian F; Schowalter, Marco; Rosenauer, Andreas; Ravishankar, Narayanan

    2018-03-14

    Ultrathin bimetallic nanowires are of importance and interest for applications in electronic devices such as sensors and heterogeneous catalysts. In this work, we have designed a new, highly reproducible and generalized wet chemical method to synthesize uniform and monodispersed Au-based alloy (AuCu, AuPd, and AuPt) nanowires with tunable composition using microwave-assisted reduction at the liquid-liquid interface. These ultrathin alloy nanowires are below 4 nm in diameter and about 2 μm long. Detailed microstructural characterization shows that the wires have an face centred cubic (FCC) crystal structure, and they have low-energy twin-boundary and stacking-fault defects along the growth direction. The wires exhibit remarkable thermal and mechanical stability that is critical for important applications. The alloy wires exhibit excellent electrocatalytic activity for methanol oxidation in an alkaline medium.

  1. Fabrication of Pt/Au concentric spheres from triblock copolymer.

    PubMed

    Koh, Haeng-Deog; Park, Soojin; Russell, Thomas P

    2010-02-23

    Dispersion of an aqueous H(2)PtCl(6) solution into a trifluorotoluene (TFT) solution of a polystyrene-block-poly(2-vinylpyridine)-block-poly(ethylene oxide) (PS-b-P2VP-b-PEO) triblock copolymer produced an emulsion-induced hollow micelle (EIHM), comprising a water nanodroplet stabilized by PEO, H(2)PtCl(6)/P2VP, and PS, sequentially. The following addition of an aqueous LiAuCl(4) solution into the dispersion led to a coordination of LiAuCl(4) and PEO. The resulting spherical EIHM structure was transformed to a hollow cylindrical micelle by the fusion of spherical EIHM with the addition of methanol. This structural transition was reversible by the alternative addition of methanol and TFT. Oxygen plasma was used to generate Pt/Au concentric spheres and hollow cylindrical Pt/Au nano-objects.

  2. First steps towards small arrays of Mo/Au microcalorimeters

    NASA Astrophysics Data System (ADS)

    Olsen, J.; Kirk, E. C.; Thomsen, K.; van den Brandt, B.; Lerch, Ph; Scandella, L.; Zehnder, A.; Mango, S.; Ott, H. R.; Huber, M.; Hilton, G. C.; Martinis, J. M.

    2000-04-01

    We are developing small arrays of microcalorimeters based on transition edge sensors made with Mo/Au bilayers deposited on silicon nitride membranes and Au absorbers. The superconducting transition of the bilayers is adjusted to be around 130 mK with a transition width better than a millikelvin by use of the proximity effect between the Au and Mo films. We built a dilution refrigerator and wired it for 2 channel operation in order to study thermal coupling issues between thermometers within the array. The device fabrication procedure as well as preliminary results are presented.

  3. A novel sandwich-type electrochemical aptasensor based on GR-3D Au and aptamer-AuNPs-HRP for sensitive detection of oxytetracycline.

    PubMed

    Liu, Su; Wang, Yu; Xu, Wei; Leng, Xueqi; Wang, Hongzhi; Guo, Yuna; Huang, Jiadong

    2017-02-15

    In this paper, a novel sandwich-type electrochemical aptasensor has been fabricated and applied for sensitive and selective detection of antibiotic oxytetracycline (OTC). This sensor was based on graphene-three dimensional nanostructure gold nanocomposite (GR-3D Au) and aptamer-AuNPs-horseradish peroxidase (aptamer-AuNPs-HRP) nanoprobes as signal amplification. Firstly, GR-3D Au film was modified on glassy carbon electrode only by one-step electrochemical coreduction with graphite oxide (GO) and HAuCl 4 at cathodic potentials, which enhanced the electron transfer and loading capacity of biomolecules. Then the aptamer and HRP modified Au nanoparticles provide high affinity and ultrasensitive electrochemical probe with excellent specificity for OTC. Under the optimized conditions, the peak current was linearly proportional to the concentration of OTC in the range of 5×10 -10 -2×10 -3 gL -1 , with a detection limit of 4.98×10 -10 gL -1 . Additionally, this aptasensor had the advantages in high sensitivity, superb specificity and showed good recovery in synthetic samples. Hence, the developed sandwich-type electrochemical aptasensor might provide a useful and practical tool for OTC determination and related food safety analysis and clinical diagnosis. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Syn-deformational features of Carlin-type Au deposits

    USGS Publications Warehouse

    Peters, S.G.

    2004-01-01

    Syn-deformational ore deposition played an important role in some Carlin-type Au deposits according to field and laboratory evidence, which indicates that flow of Au-bearing fluids was synchronous with regional-scale deformation events. Gold-related deformation events linked to ore genesis were distinct from high-level, brittle deformation that is typical of many epithermal deposits. Carlin-type Au deposits, with brittle-ductile features, most likely formed during tectonic events that were accompanied by significant fluid flow. Interactive deformation-fluid processes involved brittle-ductile folding, faulting, shearing, and gouge development that were focused along illite-clay and dissolution zones caused by hydrothermal alteration. Alteration along these deformation zones resulted in increased porosity and enhancement of fluid flow, which resulted in decarbonated, significant dissolution, collapse, and volume and mass reduction. Carlin-type Au deposits commonly are hosted in Paleozoic and Mesozoic sedimentary rocks (limestone, siltstone, argillite, shale, and quartzite) on the margins of cratons. The sedimentary basins containing the host rocks underwent tectonic events that influenced the development of stratabound, structurally controlled orebodies. Published by Elsevier Ltd.

  5. Manipulation of Spin-Torque Generation Using Ultrathin Au

    NASA Astrophysics Data System (ADS)

    An, Hongyu; Haku, Satoshi; Kanno, Yusuke; Nakayama, Hiroyasu; Maki, Hideyuki; Shi, Ji; Ando, Kazuya

    2018-06-01

    The generation and the manipulation of current-induced spin-orbit torques are of essential interest in spintronics. However, in spite of the vital progress in spin orbitronics, electric control of the spin-torque generation still remains elusive and challenging. We report on electric control of the spin-torque generation using ionic-liquid gating of ultrathin Au. We show that by simply depositing a SiO2 capping layer on an ultrathin-Au /Ni81Fe19 bilayer, the spin-torque generation efficiency is drastically enhanced by a maximum of 7 times. This enhancement is verified to be originated from the rough ultrathin-Au /Ni81Fe19 interface induced by the SiO2 deposition, which results in the enhancement of the interface spin-orbit scattering. We further show that the spin-torque generation efficiency from the ultrathin Au film can be reversibly manipulated by a factor of 2 using the ionic gating with an external electric field within a small range of 1 V. These results pave a way towards the efficient control of the spin-torque generation in spintronic applications.

  6. Single cytidine units-templated syntheses of multi-colored water-soluble Au nanoclusters

    NASA Astrophysics Data System (ADS)

    Jiang, Hui; Zhang, Yuanyuan; Wang, Xuemei

    2014-08-01

    Ultra-small metallic nanoparticles, or so-called ``nanoclusters'' (NCs), have attracted considerable interest due to their unique optical properties that are different from both larger nanoparticles and single atoms. To prepare high-quality NCs, the stabilizing agent plays an essential role. In this work, we have revealed and validated that cytidine and its nucleotides (cytidine 5'-monophosphate or cytidine 5'-triphosphate) can act as efficient stabilizers for syntheses of multicolored Au NCs. Interestingly, Au NCs with blue, green and yellow fluorescence emissions are simultaneously obtained using various pH environments or reaction times. The transmission electron microscopy verifies that the size of Au NCs ranges from 1.5 to 3 nm. The X-ray photoelectron spectroscopy confirms that only Au (0) species are present in NCs. Generally, the facile preparation of multicolored Au NCs that are stabilized by cytidine units provides access to promising candidates for multiple biolabeling applications.Ultra-small metallic nanoparticles, or so-called ``nanoclusters'' (NCs), have attracted considerable interest due to their unique optical properties that are different from both larger nanoparticles and single atoms. To prepare high-quality NCs, the stabilizing agent plays an essential role. In this work, we have revealed and validated that cytidine and its nucleotides (cytidine 5'-monophosphate or cytidine 5'-triphosphate) can act as efficient stabilizers for syntheses of multicolored Au NCs. Interestingly, Au NCs with blue, green and yellow fluorescence emissions are simultaneously obtained using various pH environments or reaction times. The transmission electron microscopy verifies that the size of Au NCs ranges from 1.5 to 3 nm. The X-ray photoelectron spectroscopy confirms that only Au (0) species are present in NCs. Generally, the facile preparation of multicolored Au NCs that are stabilized by cytidine units provides access to promising candidates for multiple

  7. Porphyry Cu-Au and associated polymetallic Fe-Cu-Au deposits in the Beiya Area, western Yunnan Province, south China

    USGS Publications Warehouse

    Xu, X.-W.; Cai, X.-P.; Xiao, Q.-B.; Peters, S.G.

    2007-01-01

    The Alkaline porphyries in the Beiya area are located east of the Jinshajiang suture, as part of a Cenozoic alkali-rich porphyry belt in western Yunnan. The main rock types include quartz-albite porphyry, quartz-K-feldspar porphyry and biotite-K-feldspar porphyry. These porphyries are characterised by high alkalinity [(K2O + Na2O)% > 10%], high silica (SiO2% > 65%), high Sr (> 400??ppm) and 87Sr/86Sr (> 0.706)] ratio and were intruded at 65.5??Ma, between 25.5 to 32.5??Ma, and about 3.8??Ma, respectively. There are five main types of mineral deposits in the Beiya area: (1) porphyry Cu-Au deposits, (2) magmatic Fe-Au deposits, (3) sedimentary polymetallic deposits, (4) polymetallic skarn deposits, and (5) palaeoplacers associated with karsts. The porphyry Cu-Au and polymetallic skarn deposits are associated with quartz-albite porphyry bodies. The Fe-Au and polymetallic sedimentary deposits are part of an ore-forming system that produced considerable Au in the Beiya area, and are characterised by low concentrations of La, Ti, and Co, and high concentrations of Y, Yb, and Sc. The Cenozoic porphyries in western Yunnan display increased alkalinity away from the Triassic Jinshajiang suture. Distribution of both the porphyries and sedimentary deposits in the Beiya area are interpreted to be related to partial melting in a disjointed region between upper mantle lithosphere of the Yangtze Plate and Gondwana continent, and lie within a shear zone between buried Palaeo-Tethyan oceanic lithosphere and upper mantle lithosphere, caused by the subduction and collision of India and Asia. ?? 2006 Elsevier B.V. All rights reserved.

  8. Catalytic activity of nanostructured Au: Scale effects versus bimetallic/bifunctional effects in low-temperature CO oxidation on nanoporous Au

    PubMed Central

    Wang, Lu-Cun; Zhong, Yi; Jin, Haijun; Widmann, Daniel; Weissmüller, Jörg

    2013-01-01

    Summary The catalytic properties of nanostructured Au and their physical origin were investigated by using the low-temperature CO oxidation as a test reaction. In order to distinguish between structural effects (structure–activity correlations) and bimetallic/bifunctional effects, unsupported nanoporous gold (NPG) samples prepared from different Au alloys (AuAg, AuCu) by selective leaching of a less noble metal (Ag, Cu) were employed, whose structure (surface area, ligament size) as well as their residual amount of the second metal were systematically varied by applying different potentials for dealloying. The structural and chemical properties before and after 1000 min reaction were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The catalytic behavior was evaluated by kinetic measurements in a conventional microreactor and by dynamic measurements in a temporal analysis of products (TAP) reactor. The data reveal a clear influence of the surface contents of residual Ag and Cu species on both O2 activation and catalytic activity, while correlations between activity and structural parameters such as surface area or ligament/crystallite size are less evident. Consequences for the mechanistic understanding and the role of the nanostructure in these NPG catalysts are discussed. PMID:23503603

  9. Tuning the Kondo effect in thin Au films by depositing a thin layer of Au on molecular spin-dopants.

    PubMed

    Ataç, D; Gang, T; Yilmaz, M D; Bose, S K; Lenferink, A T M; Otto, C; de Jong, M P; Huskens, J; van der Wiel, W G

    2013-09-20

    We report on the tuning of the Kondo effect in thin Au films containing a monolayer of cobalt(II) terpyridine complexes by altering the ligand structure around the Co(2+) ions by depositing a thin Au capping layer on top of the monolayer on Au by magnetron sputtering (more energetic) and e-beam evaporation (softer). We show that the Kondo effect is slightly enhanced with respect to that of the uncapped film when the cap is deposited by evaporation, and significantly enhanced when magnetron sputtering is used. The Kondo temperature (TK) increases from 3 to 4.2/6.2 K for the evaporated/sputtered caps. X-ray absorption spectroscopy and surface-enhanced Raman spectroscopy investigation showed that the organic ligands remain intact upon Au e-beam evaporation; however, sputtering inflicts significant change in the Co(2+) electronic environment. The location of the monolayer-on the surface or embedded in the film-has a small effect. However, the damage of Co-N bonds induced by sputtering has a drastic effect on the increase of the impurity-electron interaction. This opens up the way for tuning of the magnetic impurity states, e.g. spin quantum number, binding energy with respect to the host Fermi energy, and overlap via the ligand structure around the ions.

  10. Atrophie cérébrale diffuse au cours d'un syndrome de Goldenhar: à propos d'un cas

    PubMed Central

    Asani, Yogolelo; Mulenga, Cilundika; Ngombe, Léon Kabamba; Mbuyi-Musansayi; Muenze, Kalenga; Borasisi, Chenge; Speeg-Schatz

    2014-01-01

    Les auteurs rapportent un cas d'un syndrome de Goldenhar non décris dans la littérature chez un nourrisson de 3 mois, de sexe féminin présentant une atrophie cérébrale diffuse. Cette observation permet de décrire cette malformation rare et d'attirer l'attention de l'opinion scientifique à mettre en marche des études poussées afin de comprendre la survenue de cette pathologie. PMID:25767659

  11. Dilepton Production in p+p, Au+Au collisions at √{sNN} = 200GeV and U+U collisions at √{sNN} = 193GeV

    NASA Astrophysics Data System (ADS)

    Brandenburg, James D.; STAR Collaboration

    2017-11-01

    In this contribution we report e+e1 spectra with various invariant mass and pT differentials in Au+Au collisions at √{sNN} = 200GeV and U+U collisions at √{sNN} = 193GeV. The structure of the t (- t ≈ pT2) distributions of these mass regions will be shown and compared with the same distributions in ultra-peripheral collisions. Additionally, this contribution discusses first measurements of μ+μ- invariant mass spectra from STAR's recently installed Muon Telescope Detector (MTD) in p+p and Au+Au collisions at √{sNN} = 200GeV.

  12. Au-Ge MEAM potential fitted to the binary phase diagram

    NASA Astrophysics Data System (ADS)

    Wang, Yanming; Santana, Adriano; Cai, Wei

    2017-02-01

    We have developed a modified embedded atom method potential for the gold-germanium (Au-Ge) binary system that is fitted to the experimental binary phase diagram. The phase diagram is obtained from the common tangent construction of the free energy curves calculated by the adiabatic switching method. While maintaining the accuracy of the melting points of pure Au and Ge, this potential reproduces the eutectic temperature, eutectic composition and the solubility of Ge in solid Au, all in good agreement with the experimental values. To demonstrate the self-consistency of the potential, we performed benchmark molecular dynamics simulations of Ge crystal growth and etching in contact with a Au-Ge liquid alloy.

  13. Platinum(iv) prodrug conjugated Pd@Au nanoplates for chemotherapy and photothermal therapy

    NASA Astrophysics Data System (ADS)

    Shi, Saige; Chen, Xiaolan; Wei, Jingping; Huang, Yizhuan; Weng, Jian; Zheng, Nanfeng

    2016-03-01

    Owing to the excellent near infrared (NIR) light absorption and efficient passive targeting toward tumor tissue, two-dimensional (2D) core-shell PEGylated Pd@Au nanoplates have great potential in both photothermal therapy and drug delivery systems. In this work, we successfully conjugate Pd@Au nanoplates with a platinum(iv) prodrug c,c,t-[Pt(NH3)2Cl2(O2CCH2CH2CO2H)2] to obtain a nanocomposite (Pd@Au-PEG-Pt) for combined photothermal-chemotherapy. The prepared Pd@Au-PEG-Pt nanocomposite showed excellent stability in physiological solutions and efficient Pt(iv) prodrug loading. Once injected into biological tissue, the Pt(iv) prodrug was easily reduced by physiological reductants (e.g. ascorbic acid or glutathione) into its cytotoxic and hydrophilic Pt(ii) form and released from the original nanocomposite, and the NIR laser irradiation could accelerate the release of Pt(ii) species. More importantly, Pd@Au-PEG-Pt has high tumor accumulation (29%ID per g), which makes excellent therapeutic efficiency at relatively low power density possible. The in vivo results suggested that, compared with single therapy the combined thermo-chemotherapy treatment with Pd@Au-PEG-Pt resulted in complete destruction of the tumor tissue without recurrence, while chemotherapy using Pd@Au-PEG-Pt without irradiation or photothermal treatment using Pd@Au-PEG alone did not. Our work highlights the prospects of a feasible drug delivery strategy of the Pt prodrug by using 2D Pd@Au nanoplates as drug delivery carriers for multimode cancer treatment.Owing to the excellent near infrared (NIR) light absorption and efficient passive targeting toward tumor tissue, two-dimensional (2D) core-shell PEGylated Pd@Au nanoplates have great potential in both photothermal therapy and drug delivery systems. In this work, we successfully conjugate Pd@Au nanoplates with a platinum(iv) prodrug c,c,t-[Pt(NH3)2Cl2(O2CCH2CH2CO2H)2] to obtain a nanocomposite (Pd@Au-PEG-Pt) for combined photothermal-chemotherapy. The

  14. Azimuthal anisotropy and correlations at large transverse momenta in p + p and Au + Au collisions at square root sNN=200 GeV.

    PubMed

    Adams, J; Aggarwal, M M; Ahammed, Z; Amonett, J; Anderson, B D; Arkhipkin, D; Averichev, G S; Badyal, S K; Bai, Y; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellwied, R; Berger, J; Bezverkhny, B I; Bharadwaj, S; Bhasin, A; Bhati, A K; Bhatia, V S; Bichsel, H; Billmeier, A; Bland, L C; Blyth, C O; Bonner, B E; Botje, M; Boucham, A; Brandin, A V; Bravar, A; Bystersky, M; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca Sánchez, M; Carroll, J; Castillo, J; Cebra, D; Chajecki, Z; Chaloupka, P; Chattopdhyay, S; Chen, H F; Chen, Y; Cheng, J; Cherney, M; Chikanian, A; Christie, W; Coffin, J P; Cormier, T M; Cramer, J G; Crawford, H J; Das, D; Das, S; de Moura, M M; Derevschikov, A A; Didenko, L; Dietel, T; Dogra, S M; Dong, W J; Dong, X; Draper, J E; Du, F; Dubey, A K; Dunin, V B; Dunlop, J C; Dutta Mazumdar, M R; Eckardt, V; Edwards, W R; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Estienne, M; Fachini, P; Faivre, J; Fatemi, R; Fedorisin, J; Filimonov, K; Filip, P; Finch, E; Fine, V; Fisyak, Y; Foley, K J; Fomenko, K; Fu, J; Gagliardi, C A; Gans, J; Ganti, M S; Gaudichet, L; Geurts, F; Ghazikhanian, V; Ghosh, P; Gonzalez, J E; Grachov, O; Grebenyuk, O; Grosnick, D; Guertin, S M; Guo, Y; Gupta, A; Gutierrez, T D; Hallman, T J; Hamed, A; Hardtke, D; Harris, J W; Heinz, M; Henry, T W; Hepplemann, S; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Huang, H Z; Huang, S L; Hughes, E W; Humanic, T J; Igo, G; Ishihara, A; Jacobs, P; Jacobs, W W; Janik, M; Jiang, H; Jones, P G; Judd, E G; Kabana, S; Kang, K; Kaplan, M; Keane, D; Khodyrev, V Yu; Kiryluk, J; Kisiel, A; Kislov, E M; Klay, J; Klein, S R; Klyachko, A; Koetke, D D; Kollegger, T; Kopytine, M; Kotchenda, L; Kramer, M; Kravtsov, P; Kravtsov, V I; Krueger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kunz, C L; Kutuev, R Kh; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; Laue, F; Lauret, J; Lebedev, A; Lednicky, R; Lehocka, S; LeVine, M J; Li, C; Li, Q; Li, Y; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, L; Liu, Q J; Liu, Z; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; Lopez-Noriega, M; Love, W A; Lu, Y; Ludlam, T; Lynn, D; Ma, G L; Ma, J G; Ma, Y G; Magestro, D; Mahajan, S; Mahapatra, D P; Majka, R; Mangotra, L K; Manweiler, R; Margetis, S; Markert, C; Martin, L; Marx, J N; Matis, H S; Matulenko, Yu A; McClain, C J; McShane, T S; Meissner, F; Melnick, Yu; Meschanin, A; Miller, M L; Milosevich, Z; Minaev, N G; Mironov, C; Mischke, A; Mishra, D K; Mitchell, J; Mohanty, B; Molnar, L; Moore, C F; Morozov, D A; Munhoz, M G; Nandi, B K; Nayak, S K; Nayak, T K; Nelson, J M; Netrakanti, P K; Nikitin, V A; Nogach, L V; Nurushev, S B; Odyniec, G; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Pal, S K; Panebratsev, Y; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Peitzmann, T; Perevoztchikov, V; Perkins, C; Peryt, W; Petrov, V A; Phatak, S C; Picha, R; Planinic, M; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M; Potrebenikova, E; Potukuchi, B V K S; Prindle, D; Pruneau, C; Putschke, J; Rai, G; Rakness, G; Raniwala, R; Raniwala, S; Ravel, O; Ray, R L; Razin, S V; Reichhold, D; Reid, J G; Renault, G; Retiere, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Rose, A; Roy, C; Ruan, L; Sahoo, R; Sakrejda, I; Salur, S; Sandweiss, J; Savin, I; Sazhin, P S; Schambach, J; Scharenberg, R P; Schmitz, N; Schroeder, L S; Schweda, K; Seger, J; Seyboth, P; Shahaliev, E; Shao, M; Shao, W; Sharma, M; Shen, W Q; Shestermanov, K E; Shimanskiy, S S; Sichtermann, E; Simon, F; Singaraju, R N; Skoro, G; Smirnov, N; Snellings, R; Sood, G; Sorensen, P; Sowinski, J; Speltz, J; Spinka, H M; Srivastava, B; Stadnik, A; Stanislaus, T D S; Stock, R; Stolpovsky, A; Strikhanov, M; Stringfellow, B; Suaide, A A P; Sugarbaker, E; Suire, C; Sumbera, M; Surrow, B; Symons, T J M; Szanto de Toledo, A; Szarwas, P; Tai, A; Takahashi, J; Tang, A H; Tarnowsky, T; Thein, D; Thomas, J H; Timoshenko, S; Tokarev, M; Trentalange, S; Tribble, R E; Tsai, O D; Ulery, J; Ullrich, T; Underwood, D G; Urkinbaev, A; Van Buren, G; van Leeuwen, M; Vander Molen, A M; Varma, R; Vasilevski, I M; Vasiliev, A N; Vernet, R; Vigdor, S E; Viyogi, Y P; Vokal, S; Voloshin, S A; Vznuzdaev, M; Waggoner, W T; Wang, F; Wang, G; Wang, G; Wang, X L; Wang, Y; Wang, Y; Wang, Z M; Ward, H; Watson, J W; Webb, J C; Wells, R; Westfall, G D; Wetzler, A; Whitten, C; Wieman, H; Wissink, S W; Witt, R; Wood, J; Wu, J; Xu, N; Xu, Z; Xu, Z Z; Yamamoto, E; Yepes, P; Yurevich, V I; Zanevsky, Y V; Zhang, H; Zhang, W M; Zhang, Z P; Zolnierczuk, P A; Zoulkarneev, R; Zoulkarneeva, Y; Zubarev, A N

    2004-12-17

    Results on high transverse momentum charged particle emission with respect to the reaction plane are presented for Au + Au collisions at square root s(NN)=200 GeV. Two- and four-particle correlations results are presented as well as a comparison of azimuthal correlations in Au + Au collisions to those in p + p at the same energy. The elliptic anisotropy v(2) is found to reach its maximum at p(t) approximately 3 GeV/c, then decrease slowly and remain significant up to p(t) approximately 7-10 GeV/c. Stronger suppression is found in the back-to-back high-p(t) particle correlations for particles emitted out of plane compared to those emitted in plane. The centrality dependence of v(2) at intermediate p(t) is compared to simple models based on jet quenching.

  15. Kinetic Investigation of Homogeneous H(2)-D(2) Equilibration Catalyzed by Pt-Au Cluster Compounds. Characterization of the Cluster [(H)Pt(AuPPh(3))(9)](NO(3))(2).

    PubMed

    Rubinstein, Leon I.; Pignolet, Louis H.

    1996-11-06

    The new Pt-Au hydrido cluster compound [(H)Pt(AuPPh(3))(9)](NO(3))(2) (3) has been synthesized and characterized by NMR, FABMS, and single-crystal X-ray diffraction [triclinic, P&onemacr;, a = 17.0452(1) Å, b = 17.4045(2) Å, c = 55.2353(1) Å, alpha = 89.891(1) degrees, beta = 85.287(1) degrees, gamma = 75.173(1) degrees, V = 15784.0(2) Å(3), Z = 4 (two molecules in asymmetric unit), residual R = 0.089 for 45 929 observed reflections and 3367 variables, Mo Kalpha radiation]. The Pt(AuP)(9) core geometry is a distorted icosahedron with three vertices vacant. The Pt-Au, Au-Au, and Au-P distances are within the normal ranges observed in other Pt-Au clusters. This cluster is a catalyst for H(2)-D(2) equilibration in homogeneous solution phase and has been used in a general mechanistic study of this reaction catalyzed by Pt-Au clusters. We previously proposed that a key step in the mechanism for catalytic H(2)-D(2) equilibration is the dissociation of a PPh(3) ligand to give a cluster with an open Au site for bonding of H(2) or D(2). This was based on qualitative observations that PPh(3) inhibited the rate of HD production with [Pt(AuPPh(3))(8)](NO(3))(2) (1) as catalyst. In order to test this hypothesis, phosphine inhibition (on the rate of HD production) and phosphine ligand exchange kinetic experiments were carried out with [(H)(PPh(3))Pt(AuPPh(3))(7)](NO(3))(2) (2) and 3. In this paper we show that the rate constant for phosphine dissociation determined from the PPh(3) inhibition rate study of H(2)-D(2) equilibration with cluster 2 is nearly identical to the rate constant for dissociative phosphine ligand exchange. The slower rate for H(2)-D(2) equilibration observed with 3 compared with 2 (5.5 x 10(-3) vs 7.7 x 10(-2) turnover s(-1)) is explained by its smaller rate constant for phosphine dissociation (2.8 x 10(-5) vs 2.9 x 10(-4) s(-1)). The fact that clusters 2 and 3 show similar kinetic behaviors suggests that the PPh(3) dissociation step in the catalytic H(2

  16. Determination of Impact Parameters in Aligned Breakup of Projectile-like Fragments in $$^{197}$$Au + $$^{197}$$Au Collisions at 23$A$MeV

    DOE PAGES

    Cap, T.; Siwek-Wilczyńska, K.; Wilczynski, J.; ...

    2016-03-01

    Symmetric and asymmetric aligned breakup of projectile-like fragments inmore » $$^{197}$$Au + $$^{197}$$Au collisions at 23$A$,MeV was studied. Independently of the asymmetry, the reaction yields have been found peaked at a common, very narrow range of impact parameters.« less

  17. Biosupported Bimetallic Pd Au Nanocatalysts for Dechlorination of Environmental Contaminants

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    De Corte, S.; Fitts, J.; Hennebel, T.

    2011-08-30

    Biologically produced monometallic palladium nanoparticles (bio-Pd) have been shown to catalyze the dehalogenation of environmental contaminants, but fail to efficiently catalyze the degradation of other important recalcitrant halogenated compounds. This study represents the first report of biologically produced bimetallic Pd/Au nanoparticle catalysts. The obtained catalysts were tested for the dechlorination of diclofenac and trichloroethylene. When aqueous bivalent Pd(II) and trivalent Au(III) ions were both added to concentrations of 50 mg L{sup -1} and reduced simultaneously by Shewanella oneidensis in the presence of H{sub 2}, the resulting cell-associated bimetallic nanoparticles (bio-Pd/Au) were able to dehalogenate 78% of the initially added diclofenacmore » after 24 h; in comparison, no dehalogenation was observed using monometallic bio-Pd or bio-Au. Other catalyst-synthesis strategies did not show improved dehalogenation of TCE and diclofenac compared with bio-Pd. Synchrotron-based X-ray diffraction, (scanning) transmission electron microscopy and energy dispersive X-ray spectroscopy indicated that the simultaneous reduction of Pd and Au supported on cells of S. oneidensis resulted in the formation of a unique bimetallic crystalline structure. This study demonstrates that the catalytic activity and functionality of possibly environmentally more benign biosupported Pd-catalysts can be improved by coprecipitation with Au.« less

  18. Centrality Dependence of Charged Hadron Transverse Momentum Spectra in Au+Au Collisions from √(sNN)=62.4 to 200 GeV

    NASA Astrophysics Data System (ADS)

    Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Busza, W.; Carroll, A.; Chai, Z.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Halliwell, C.; Hamblen, J.; Hauer, M.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Reed, C.; Roland, C.; Roland, G.; Sagerer, J.; Seals, H.; Sedykh, I.; Smith, C. E.; Stankiewicz, M. A.; Steinberg, P.; Stephans, G. S.; Sukhanov, A.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Wenger, E.; Wolfs, F. L.; Wosiek, B.; Woźniak, K.; Wysłouch, B.

    2005-03-01

    We have measured transverse momentum distributions of charged hadrons produced in Au+Au collisions at √(sNN)=62.4 GeV. The spectra are presented for transverse momenta 0.25Au+Au collisions at √(sNN)= 130 and 200 GeV. In contrast to the large change in RAA, we observe a very similar centrality evolution of the pT spectra at √(sNN)=62.4 and 200 GeV. The dynamical origin of this surprising factorization of energy and centrality dependence of particle production in heavy-ion collisions remains to be understood.

  19. Active control of methanol carbonylation selectivity over Au/carbon anode by electrochemical potential.

    PubMed

    Funakawa, Akiyasu; Yamanaka, Ichiro; Otsuka, Kiyoshi

    2005-05-12

    Electrochemical oxidative carbonylation of methanol was studied over Au supported carbon anode in CO. The major carbonylation products were dimethyl oxalate (DMO) and dimethyl carbonate (DMC). The minor oxidation products were dimethoxy methane (DMM) and methyl formate (MF) from methanol and CO(2). Influences of various reaction conditions were studied on carbonylation activities and selectivities. The selectivities to DMO and DMC can be controlled by the electrochemical potential. Electrocatalysis of Au/carbon anode was studied by cyclic voltammetry (CV), stoichiometric reactions among Au(3+), methanol, and CO, and UV-vis spectra. The Au/carbon anode was characterized by XRD, SEM, and BE images before and after the carbonylation. These experimental facts strongly suggest that transition of oxidation states of Au affects changing of the carbonylation selectivities to DMO and DMC. Au(0) is the active species for the selective DMO formation by direct electrochemical carbonylation at low potentials (<+1.2 V (Ag/AgCl)). On the other hand, Au(3+) is the active spices for the selective DMC formation by indirect electrochemical carbonylation through Au(3+)/Au(+) redox at high potentials (>+1.3 V).

  20. Enhanced catalyst activity by decorating of Au on Ag@Cu2O nanoshell

    NASA Astrophysics Data System (ADS)

    Chen, Lei; Liu, Maomao; Zhao, Yue; Kou, Qiangwei; Wang, Yaxin; Liu, Yang; Zhang, Yongjun; Yang, Jinghai; Jung, Young Mee

    2018-03-01

    We successfully synthesized Au-decorated Ag@Cu2O heterostructures via a simple galvanic replacement method. As the Au precursor concentration increased, the density of the Au nanoparticles (NPs) on the Ag@Cu2O surface increased, which changed the catalytic activity of the Ag@Cu2O-Au structure. The combination of Au, Ag, and Cu2O exhibited excellent catalytic properties, which can further effect on the catalyst activity of the Ag@Cu2O-Au structure. In addition, the proposed Ag@Cu2O-Au nanocomposite was used to transform the organic, toxic pollutant, 4-nitrophenol (4-NP), into its nontoxic and medicinally important amino derivative via a catalytic reduction to optimize the material performance. The proposed Au-decorated Ag@Cu2O exhibited excellent catalytic activity, and the catalytic reduction time greatly decreased (5 min). Thus, three novel properties of Ag@Cu2O-Au, i.e., charge redistribution and transfer, adsorption, and catalytic reduction of organic pollutants, were ascertained for water remediation. The proposed catalytic properties have potential applications for photocatalysis and localized surface plasmon resonance (LSPR)- and peroxidase-like catalysis.

  1. Crystal Structure of Faradaurate-279: Au279(SPh-tBu)84 Plasmonic Nanocrystal Molecules.

    PubMed

    Sakthivel, Naga Arjun; Theivendran, Shevanuja; Ganeshraj, Vigneshraja; Oliver, Allen G; Dass, Amala

    2017-11-01

    We report the discovery of an unprecedentedly large, 2.2 nm diameter, thiolate protected gold nanocrystal characterized by single crystal X-ray crystallography (sc-XRD), Au 279 (SPh-tBu) 84 named Faradaurate-279 (F-279) in honor of Michael Faraday's (1857) pioneering work on nanoparticles. F-279 nanocrystal has a core-shell structure containing a truncated octahedral core with bulk face-centered cubic-like arrangement, yet a nanomolecule with a precise number of metal atoms and thiolate ligands. The Au 279 S 84 geometry was established from a low-temperature 120 K sc-XRD study at 0.90 Å resolution. The atom counts in core-shell structure of Au 279 follows the mathematical formula for magic number shells: Au@Au 12 @Au 42 @Au 92 @Au 54 , which is further protected by a final shell of Au 48 . Au 249 core is protected by three types of staple motifs, namely: 30 bridging, 18 monomeric, and 6 dimeric staple motifs. Despite the presence of such diverse staple motifs, Au 279 S 84 structure has a chiral pseudo-D 3 symmetry. The core-shell structure can be viewed as nested, concentric polyhedra, containing a total of five forms of Archimedean solids. A comparison between the Au 279 and Au 309 cuboctahedral superatom model in shell-wise growth is illustrated. F-279 can be synthesized and isolated in high purity in milligram quantities using size exclusion chromatography, as evidenced by mass spectrometry. Electrospray ionization-mass spectrometry independently verifies the X-ray diffraction study based heavy atoms formula, Au 279 S 84 , and establishes the molecular formula with the complete ligands, namely, Au 279 (SPh-tBu) 84 . It is also the smallest gold nanocrystal to exhibit metallic behavior, with a surface plasmon resonance band around 510 nm.

  2. Reduction of HAuCl 4 by Na 2S revisited: The case for Au nanoparticle aggregates and against Au 2S/Au core/shell particles

    DOE PAGES

    Schwartzberg, A. M.; Grant, C. D.; van Buuren, Tony; ...

    2007-03-10

    The reaction of sodium sulfide with chloroauric acid has been surrounded by a controversy over the structure of the resulting product. The original report proposed a Au 2S/Au core/shell structure based on strong near-IR resonance and limited transmission electron microscopy. Subsequent reports used the same model without further attempts to determine the structure of the products. With a significant body of experimental work compiled over a period of several years, we have shown that the major product of this reaction is aggregated spherical nanoparticles of gold with a minority component consisting of triangular and rod-like structures. This is in contradictionmore » to the core/shell structures as originally proposed. Recently, there have been additional reports that again suggest a Au 2S/Au core/shell structure or irregularly shaped Au nanoparticles as an explanation for the near-IR resonance. To help resolve this issue, we have carried out further experiments to determine how the reaction products may depend on experimental conditions such as concentration and aging of the reactants, particularly Na 2S. It has been determined that sodium thiosulfate is the likely product from Na 2S aging. In addition, persistent spectral hole burning experiments have been conducted on gold nanoparticle aggregate (GNA) samples at excitation intensities that are lower than that required to melt the nanostructures. We have observed a decrease in optical absorption on resonance with the excitation laser wavelength, with simultaneous increases in absorption to the blue and red of this wavelength region. However, in the presence of the stabilizer poly(vinyl pyrrolidone) (PVP), no increase in absorbance was observed but rather a blue shifting and decrease in intensity of the near-IR plasmon resonance. These results imply that the non-stabilized GNAs are able to break apart and reform into off resonant aggregate structures. In contrast, this behavior is suppressed in PVP stabilized

  3. Azimuthal Angle Dependence of HBT Radii in Au+Au Collisions at RHIC-PHENIX

    NASA Astrophysics Data System (ADS)

    Niida, Takafumi

    Measurement of Hanbury-Brown and Twiss (HBT) interferometry with respect to the event plane have been performed in Au+Au collisions at √{sNN} = 200 GeV at PHENIX, which is a unique tool to study the spatial extent of the created matter at final state in heavy ion collisions and the detailed picture of the space-time evolution from the initial state to the final state. The Gaussian source radii was measured for charged pions and kaons with respect to 2nd-order event plane. There was a difference in final eccentricity between both species, which may imply the different freeze-out mechanism by the particle species. The pion source radii was also measured relative to 3rd-order event plane, and the azimuthal angle dependence of the radii was observed, which qualitatively agrees with the recent hydrodynamic calculation and the oscillation may be driven from the triangular flow.

  4. Bendable solid-state supercapacitors with Au nanoparticle-embedded graphene hydrogel films

    PubMed Central

    Yang, Kyungwhan; Cho, Kyoungah; Yoon, Dae Sung; Kim, Sangsig

    2017-01-01

    In this study, we fabricate bendable solid-state supercapacitors with Au nanoparticle (NP)-embedded graphene hydrogel (GH) electrodes and investigate the influence of the Au NP embedment on the internal resistance and capacitive performance. Embedding the Au NPs into the GH electrodes results in a decrease of the internal resistance from 35 to 21 Ω, and a threefold reduction of the IR drop at a current density of 5 A/g when compared with GH electrodes without Au NPs. The Au NP-embedded GH supercapacitors (NP-GH SCs) exhibit excellent capacitive performances, with large specific capacitance (135 F/g) and high energy density (15.2 W·h/kg). Moreover, the NP-GH SCs exhibit comparable areal capacitance (168 mF/cm2) and operate under tensile/compressive bending. PMID:28074865

  5. Synthesis and electrocatalytic activity of Au/Pt bimetallic nanodendrites for ethanol oxidation in alkaline medium.

    PubMed

    Han, Xinyi; Wang, Dawei; Liu, Dong; Huang, Jianshe; You, Tianyan

    2012-02-01

    Gold/Platinum (Au/Pt) bimetallic nanodendrites were successfully synthesized through seeded growth method using preformed Au nanodendrites as seeds and ascorbic acid as reductant. Cyclic voltammograms (CVs) of a series of Au/Pt nanodendrites modified electrodes in 1M KOH solution containing 1M ethanol showed that the electrocatalyst with a molar ratio (Au:Pt) of 3 exhibited the highest peak current density and the lowest onset potential. The peak current density of ethanol electro-oxidation on the Au(3)Pt(1) nanodendrites modified glassy carbon electrode (Au(3)Pt(1) electrode) is about 16, 12.5, and 4.5 times higher than those on the polycrystalline Pt electrode, polycrystalline Au electrode, and Au nanodendrites modified glassy carbon electrode (Au dendrites electrode), respectively. The oxidation peak potential of ethanol electro-oxidation on the Au(3)Pt(1) electrode is about 299 and 276 mV lower than those on the polycrystalline Au electrode and Au dendrites electrode, respectively. These results demonstrated that the Au/Pt bimetallic nanodendrites may find potential application in alkaline direct ethanol fuel cells (ADEFCs). Copyright © 2011 Elsevier Inc. All rights reserved.

  6. Mecanismes de deformation de nanoparticules d'Au par irradiation ionique

    NASA Astrophysics Data System (ADS)

    Harkati Kerbouah, Chahineze

    2011-12-01

    In the present thesis, we study the anisotropic deformation of gold nanoparticles embedded in amorphous silica or crystalline aluminum arsenide, under ion bombardment. We try to comprehend the mechanism responsible for this deformation and to remove any ambiguity related to the explanation of this phenomenon. A hybrid process combining sputtering and plasma enhanced chemical vapour deposition was used to fabricate Au/SiO2 layers on fused silica substrates. Structures with single and multilayer were obtained. Heating during or after deposition activates the Au atom agglomeration and favours the growth of the nanoparticles. Also, a Au/AlAs nanocomposite was obtained by ion implantation of AlAs films, followed by rapid thermal annealing. The samples of the two nanocomposites, cooled with liquid nitrogen, were irradiated with 2 to 40 MeV Cu, Si, Au or In ion beams, at fluences ranging from 1x10 13 to 4x1015 ions/cm2, using a Tandem or Tandetron accelerator. The structural and morphological properties of the Au/SiO2 nanocomposite were extracted by optical means; the frequency and the width of surface plasmon resonance band depend on the nanoparticle shape and size, their concentration, the inter-particle distance and the dielectric properties of material in which the particles are embedded. The aluminum arsenide crystallinity was studied by two techniques: Raman spectroscopy and Rutherford backscattering spectrometry in channelling configuration (RBS/ channelling). The Au concentration in the nanocomposite layers was deducted from RBS results. The size distribution and metallic nanoparticles shape transformation in both nanocomposites were observed by electronic transmission microscopy. The results obtained within the framework of this work are the subject of three journal papers. The first publication shows the possibility of manipulating the width and spectral position of the gold nanoparticle absorption band in Au/SiO2 nanocomposites by modifying their structure

  7. Kinetically controlled synthesis of Au102(SPh)44 nanoclusters and catalytic application.

    PubMed

    Chen, Yongdong; Wang, Jin; Liu, Chao; Li, Zhimin; Li, Gao

    2016-05-21

    We here explore a kinetically controlled synthetic protocol for preparing solvent-solvable Au102(SPh)44 nanoclusters which are isolated from polydispersed gold nanoclusters by solvent extraction and size exclusion chromatography (SEC). The as-obtained Au102(SPh)44 nanoclusters are determined by matrix-assisted laser desorption ionization (MALDI) and electrospray ionization (ESI) mass spectrometry, in conjunction with UV-vis spectroscopy and thermogravimetric analysis (TGA). However, Au99(SPh)42, instead of Au102(SPh)44, is yielded when the polydispersed gold nanoclusters are etched in the presence of excess thiophenol under thermal conditions (e.g., 80 °C). Interestingly, the Au102(SPh)44 nanoclusters also can convert to Au99(SPh)42 with equivalent thiophenol ligands, evidenced by the analyses of UV-vis and MALDI mass spectrometry. Finally, the TiO2-supported Au102(SPh)44 nanocluster catalyst is investigated in the selective oxidation of sulfides into sulfoxides by the PhIO oxidant and gives rise to high catalytic activity (e.g., 80-99% conversion of R-S-R' sulfides with 96-99% selectivity for R-S([double bond, length as m-dash]O)-R' sulfoxides). The Au102(SPh)44/TiO2 catalyst also shows excellent recyclability in the sulfoxidation process.

  8. Au Nanoparticle Sub-Monolayers Sandwiched between Sol-Gel Oxide Thin Films

    PubMed Central

    Della Gaspera, Enrico; Menin, Enrico; Sada, Cinzia

    2018-01-01

    Sub-monolayers of monodisperse Au colloids with different surface coverage have been embedded in between two different metal oxide thin films, combining sol-gel depositions and proper substrates functionalization processes. The synthetized films were TiO2, ZnO, and NiO. X-ray diffraction shows the crystallinity of all the oxides and verifies the nominal surface coverage of Au colloids. The surface plasmon resonance (SPR) of the metal nanoparticles is affected by both bottom and top oxides: in fact, the SPR peak of Au that is sandwiched between two different oxides is centered between the SPR frequencies of Au sub-monolayers covered with only one oxide, suggesting that Au colloids effectively lay in between the two oxide layers. The desired organization of Au nanoparticles and the morphological structure of the prepared multi-layered structures has been confirmed by Rutherford backscattering spectrometry (RBS), Secondary Ion Mass Spectrometry (SIMS), and Scanning Electron Microscopy (SEM) analyses that show a high quality sandwich structure. The multi-layered structures have been also tested as optical gas sensors. PMID:29538338

  9. Au36(SePh)24 nanomolecules: synthesis, optical spectroscopy and theoretical analysis.

    PubMed

    Rambukwella, Milan; Chang, Le; Ravishanker, Anish; Fortunelli, Alessandro; Stener, Mauro; Dass, Amala

    2018-05-16

    Here, we report the synthesis of selenophenol (HSePh) protected Au36(SePh)24 nanomolecules via a ligand-exchange reaction of 4-tert-butylbenzenethiol (HSPh-tBu) protected Au36(SPh-tBu)24 with selenophenol, and its spectroscopic and theoretical analysis. Matrix assisted laser desorption ionization (MALDI) mass spectrometry, electrospray ionization (ESI) mass spectrometry and optical characterization confirm that the composition of the as synthesized product is predominantly Au36(SePh)24 nanomolecules. Size exclusion chromatography (SEC) was employed to isolate the Au36(SePh)24 and temperature dependent optical absorption studies and theoretical analysis were performed. Theoretically, an Independent Component Maps of Oscillator Strength (ICM-OS) analysis of simulated spectra shows that the enhancement in absorption intensity in Au36(SePh)24 with respect to Au36(SPh)24 can be ascribed to the absence of interference and/or increased long-range coupling between interband metal core and ligand excitations. This work demonstrates and helps to understand the effect of Au-Se bridging on the properties of gold nanomolecules.

  10. Au nanoparticles films used in biological sensing

    NASA Astrophysics Data System (ADS)

    Rosales Pérez, M.; Delgado Macuil, R.; Rojas López, M.; Gayou, V. L.; Sánchez Ramírez, J. F.

    2009-05-01

    Lactobacillus para paracasei are used commonly as functional food and probiotic substances. In this work Au nanoparticles self-assembled films were used for Lactobacillus para paracasei determination at five different concentrations. Functionalized substrates were immersed in a colloidal solution for one and a half hour at room temperature and dried at room temperature during four hours. After that, drops of Lactobacillus para paracasei in aqueous solution were put into the Au nanoparticles film and let dry at room temperature for another two hours. Infrared spectroscopy in attenuated total reflectance sampling mode was used to observe generation peaks due to substrate silanization, enhancement of Si-O band intensity due to the Au colloids added to silanized substrate and also to observe the enhancement of Lactobacillus para paracasei infrared intensity of the characteristic frequencies at 1650, 1534 and 1450 cm-1 due to surface enhancement infrared absorption.

  11. An investigation of enhanced secondary ion emission under Au(n)+ (n = 1-7) bombardment.

    PubMed

    Nagy, G; Gelb, L D; Walker, A V

    2005-05-01

    We investigate the mechanism of the nonlinear secondary ion yield enhancement using Au(n)+ (n = 1, 2, 3, 5, 7) primary ions bombarding thin films of Irganox 1010, DL-phenylalanine and polystyrene on Si, Al, and Ag substrates. The largest differences in secondary ion yields are found using Au+, Au2+, and Au3+ primary ion beams. A smaller increase in secondary ion yield is observed using Au5+ and Au7+ primary ions. The yield enhancement is found to be larger on Si than on Al, while the ion yield is smaller using an Au+ beam on Si than on Al. Using Au(n)+ ion structures obtained from Density Functional Theory, we demonstrate that the secondary yield enhancement is not simply due to an increase in energy per area deposited into the surface (energy deposition density). Instead, based on simple mechanical arguments and molecular dynamics results from Medvedeva et al, we suggest a mechanism for nonlinear secondary ion yield enhancement wherein the action of multiple concerted Au impacts leads to efficient energy transfer to substrate atoms in the near surface region and an increase in the number of secondary ions ejected from the surface. Such concerted impacts involve one, two, or three Au atoms, which explains well the large nonlinear yield enhancements observed going from Au+ to Au2+ to Au3+ primary ions. This model is also able to explain the observed substrate effect. For an Au+ ion passing through the more open Si surface, it contacts fewer substrate atoms than in the more dense Al surface. Less energy is deposited in the Si surface region by the Au+ primary ion and the secondary ion yield will be lower for adsorbates on Si than on Al. In the case of Au(n)+ the greater density of Al leads to earlier break-up of the primary ion and a consequent reduction in energy transfer to the near-surface region when compared with Si. This results in higher secondary ion yields and yield enhancements on silicon than aluminum substrates.

  12. Vapochromic Behaviour of M[Au(CN)2]2-Based Coordination Polymers (M = Co, Ni)

    PubMed Central

    Lefebvre, Julie; Korčok, Jasmine L.; Katz, Michael J.; Leznoff, Daniel B.

    2012-01-01

    A series of M[Au(CN)2]2(analyte)x coordination polymers (M = Co, Ni; analyte = dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), pyridine; x = 2 or 4) was prepared and characterized. Addition of analyte vapours to solid M(μ-OH2)[Au(CN)2]2 yielded visible vapochromic responses for M = Co but not M = Ni; the IR νCN spectral region changed in every case. A single crystal structure of Zn[Au(CN)2]2(DMSO)2 revealed a corrugated 2-D layer structure with cis-DMSO units. Reacting a Ni(II) salt and K[Au(CN)2] in DMSO yielded the isostructural Ni[Au(CN)2]2(DMSO)2 product. Co[Au(CN)2]2(DMSO)2 and M[Au(CN)2]2(DMF)2 (M = Co, Ni) complexes have flat 2-D square-grid layer structures with trans-bound DMSO or DMF units; they are formed via vapour absorption by solid M(μ-OH2)[Au(CN)2]2 and from DMSO or DMF solution synthesis. Co[Au(CN)2]2(pyridine)4 is generated via vapour absorption by Co(μ-OH2)[Au(CN)2]2; the analogous Ni complex is synthesized by immersion of Ni(μ-OH2)[Au(CN)2]2 in 4% aqueous pyridine. Similar immersion of Co(μ-OH2)[Au(CN)2]2 yielded Co[Au(CN)2]2(pyridine)2, which has a flat 2-D square-grid structure with trans-pyridine units. Absorption of pyridine vapour by solid Ni(μ-OH2)[Au(CN)2]2 was incomplete, generating a mixture of pyridine-bound complexes. Analyte-free Co[Au(CN)2]2 was prepared by dehydration of Co(μ-OH2)[Au(CN)2]2 at 145 °C; it has a 3-D diamondoid-type structure and absorbs DMSO, DMF and pyridine to give the same materials as by vapour absorption from the hydrate. PMID:22737031

  13. Structural, (197)Au Mössbauer and solid state (31)P CP/MAS NMR studies on bis (cis-bis(diphenylphosphino)ethylene) gold(I) complexes [Au(dppey)(2)]X for X = PF(6), I.

    PubMed

    Healy, Peter C; Loughrey, Bradley T; Bowmaker, Graham A; Hanna, John V

    2008-07-28

    (197)Au Mössbauer spectra for the d(10) gold(i) phosphine complexes, [Au(dppey)(2)]X (X = PF(6), I; dppey = (cis-bis(diphenylphosphino)ethylene), and the single crystal X-ray structure and solid state (31)P CPMAS NMR spectrum of [Au(dppey)(2)]I are reported here. In [Au(dppey)(2)]I the AuP(4) coordination geometry is distorted from the approximately D(2) symmetry observed for the PF(6)(-) complex with Au-P bond lengths 2.380(2)-2.426(2) A and inter-ligand P-Au-P angles 110.63(5)-137.71(8) degrees . Quadrupole splitting parameters derived from the Mössbauer spectra are consistent with the increased distortion of the AuP(4) coordination sphere with values of 1.22 and 1.46 mm s(-1) for the PF(6)(-) and I(-) complexes respectively. In the solid state (31)P CP MAS NMR spectrum of [Au(dppey)(2)]I, signals for each of the four crystallographically independent phosphorus nuclei are observed, with the magnitude of the (197)Au quadrupole coupling being sufficiently large to produce a collapse of (1)J(Au-P) splitting from quartets to doublets. The results highlight the important role played by the counter anion in the determination of the structural and spectroscopic properties of these sterically crowded d(10) complexes.

  14. Embedded atom method potential for studying mechanical properties of binary Cu–Au alloys

    NASA Astrophysics Data System (ADS)

    Gola, Adrien; Pastewka, Lars

    2018-07-01

    We present an embedded atom method (EAM) potential for the binary Cu–Au system. The unary phases are described by two well-tested unary EAM potentials for Cu and Au. We fitted the interaction between Cu and Au to experimental properties of the binary intermetallic phases Cu3Au, CuAu and CuAu3. Particular attention has been paid to reproducing stacking fault energies in order to obtain a potential suitable for studying deformation in this binary system. The resulting energies, lattice constant, elastic properties and melting points are in good agreement with available experimental data. We use nested sampling to show that our potential reproduces the phase boundaries between intermetallic phases and the disordered face-centered cubic solid solution. We benchmark our potential against four popular Cu–Au EAM parameterizations and density-functional theory calculations.

  15. Efficient Removal of Methane over Cobalt-Monoxide-Doped AuPd Nanocatalysts.

    PubMed

    Xie, Shaohua; Liu, Yuxi; Deng, Jiguang; Zang, Simiao; Zhang, Zhenhua; Arandiyan, Hamidreza; Dai, Hongxing

    2017-02-21

    To overcome deactivation of Pd-based catalysts at high temperatures, we herein design a novel pathway by introducing a certain amount of CoO to the supported Au-Pd alloy nanoparticles (NPs) to generate high-performance Au-Pd-xCoO/three-dimensionally ordered macroporous (3DOM) Co 3 O 4 (x is the Co/Pd molar ratio) catalysts. The doping of CoO induced the formation of PdO-CoO active sites, which was beneficial for the improvement in adsorption and activation of CH 4 and catalytic performance. The Au-Pd-0.40CoO/3DOM Co 3 O 4 sample performed the best (T 90% = 341 °C at a space velocity of 20 000 mL g -1 h -1 ). Deactivation of the 3DOM Co 3 O 4 -supported Au-Pd, Pd-CoO, and Au-Pd-xCoO nanocatalysts resulting from water vapor addition was due to the formation and accumulation of hydroxyl on the catalyst surface, whereas deactivation of the Pd-CoO/3DOM Co 3 O 4 catalyst at high temperatures (680-800 °C) might be due to decomposition of the PdO y active phase into aggregated Pd 0 NPs. The Au-Pd-xCoO/3DOM Co 3 O 4 nanocatalysts exhibited better thermal stability and water tolerance ability compared to the 3DOM Co 3 O 4 -supported Au-Pd and Pd-CoO nanocatalysts. We believe that the supported Au-Pd-xCoO nanomaterials are promising catalysts in practical applications for organic combustion.

  16. Low frequency noise in the unstable contact region of Au-to-Au microcontact for microelectromechanical system switches

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Qiu, Haodong; Wang, Hong, E-mail: ewanghong@ntu.edu.sg; Ke, Feixiang

    The noise behavior of Au-to-Au microcontact for microelectromechanical system switches has been experimentally studied in the unstable contact region. The results suggest that the electrical conduction remains nonmetallic at the initial stage during contact formation due to the existence of alien films, and traps in the alien layer located at the contact interface could play an important role in determining the conduction noise. The conduction fluctuation induced by electron trapping-detrapping associated with the hydrocarbon layer is found to be an intrinsic noise source contributing to the low frequency noise in the unstable contact region.

  17. Low frequency noise in the unstable contact region of Au-to-Au microcontact for microelectromechanical system switches

    NASA Astrophysics Data System (ADS)

    Qiu, Haodong; Wang, Hong; Ke, Feixiang

    2014-06-01

    The noise behavior of Au-to-Au microcontact for microelectromechanical system switches has been experimentally studied in the unstable contact region. The results suggest that the electrical conduction remains nonmetallic at the initial stage during contact formation due to the existence of alien films, and traps in the alien layer located at the contact interface could play an important role in determining the conduction noise. The conduction fluctuation induced by electron trapping-detrapping associated with the hydrocarbon layer is found to be an intrinsic noise source contributing to the low frequency noise in the unstable contact region.

  18. Gigantic transverse x-ray magnetic circular dichroism in ultrathin Co in Au/Co/Au(001)

    NASA Astrophysics Data System (ADS)

    Koide, T.; Mamiya, K.; Asakura, D.; Osatune, Y.; Fujimori, A.; Suzuki, Y.; Katayama, T.; Yuasa, S.

    2014-04-01

    Transverse-geometry x-ray magnetic circular dichroism (TXMCD) measurements on Au/Co-staircase/Au(001) reveal the orbital origin of intrinsic in-plane magnetic anisotropy A gigantic TXMCD was successfully observed at the Co L3,2 edges for Co thickness (tC0) in the 2-monolayer regime. A TXMCD-sum-rule analysis shows a remarkable enhancement of an orbital-moment anisotropy (Δmorb) and of an in-plane magnetic dipole moment (m||T). Both Δmorb and m||T exhibit close similarity in tCo dependence, reflecting the in-plane magnetic anisotropy These observations evidence that extremely strong, intrinsic, in-plane magnetic anisotropy originates from the anisotropic orbital part of the wave function, dominating the dipole-dipole-interaction-derived, extrinsic, in-plane magnetic anisotropy.

  19. Architecture effects of glucose oxidase/Au nanoparticle composite Langmuir-Blodgett films on glucose sensing performance

    NASA Astrophysics Data System (ADS)

    Wang, Ke-Hsuan; Wu, Jau-Yann; Chen, Liang-Huei; Lee, Yuh-Lang

    2016-03-01

    The Langmuir-Blodgett (LB) deposition technique is employed to prepare nano-composite films consisting of glucose oxidase (GOx) and gold nanoparticles (AuNPs) for glucose sensing applications. The GOx and AuNPs are co-adsorbed from an aqueous solution onto an air/liquid interface in the presence of an octadecylamine (ODA) template monolayer, forming a mixed (GOx-AuNP) monolayer. Alternatively, a composite film with a cascade architecture (AuNP/GOx) is also prepared by sequentially depositing monolayers of AuNPs and GOx. The architecture effects of the composite LB films on the glucose sensing are studied. The results show that the presence of AuNPs in the co-adsorption system does not affect the adsorption amount and preferred conformation (α-helix) of GOx. Furthermore, the incorporation of AuNPs in both composite films can significantly improve the sensing performance. However, the enhancement effects of the AuNPs in the two architectures are distinct. The major effect of the AuNPs is on the facilitation of charge-transfer in the (GOx-AuNP) film, but on the increase of catalytic activity in the (AuNP/GOx) one. Therefore, the sensing performance can be greatly improved by utilizing a film combining both architectures (AuNP/GOx-AuNP).

  20. La supraconductivité a 100 ans !

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lebrun, Philippe

    2011-04-14

    Il y a 100 ans, le 8 avril 1911, une découverte majeure était réalisée : celle de la supraconductivité. La supraconductivité est la caractéristique qu’ont certains métaux et alliages de perdre toute résistance électrique en dessous d’une température donnée. Cette renversante découverte, réalisée de manière presque fortuite par Kammerlingh Onnes de l’Université de Leyde (Pays-Bas) et son étudiant Gilles Holst, a ouvert un nouveau champ de recherche en physique et de fabuleuses perspectives d’applications technologiques. Du point de vue scientifique, la supraconductivité est en effet l’une des rares manifestations de la physique quantique à l’échelle macroscopique.  Du point de vuemore » des retombées techniques, elle est porteuse d’applications majeures dans le domaine de la santé, des communications et de l’énergie. 100 ans après, les physiciens n’ont toujours pas fini d’explorer ce phénomène et ses applications. Le CERN abrite des applications de la supraconductivité à des échelles inédites. L’accélérateur de particules LHC, avec ses milliers d’aimants supraconducteurs répartis sur 27 kilomètres de circonférence, est en effet la plus grande application mondiale de la supraconductivité. Il ne pourrait exister sans elle. Le CERN fête donc la découverte de la supraconductivité avec une conférence exceptionnelle donnée par Philippe Lebrun. Au cours de cette conférence, l’expérience historique de Kammerlingh Onnes sera reproduite. Philippe Lebrun racontera l’histoire de cette étonnante découverte, en la replaçant dans le contexte scientifique de l’époque. Il racontera les développements scientifiques et les applications du premier siècle de la supraconductivité. Conférence en français Merci de bien vouloir vous inscrire au : +41 22 767 76 76 ou cern.reception@cern.ch« less