34 research outputs found

    Synthesis, characterization, monolayer assembly and 2D lanthanide coordination of a linear terphenyl-di(propiolonitrile) linker on Ag(111)

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    As a continuation of our work employing polyphenylene-dicarbonitrile molecules and in particular the terphenyl derivative 1 (TDCN), we have synthesized a novel ditopic terphenyl-4,4”-di(propiolonitrile) (2) linker for the self-assembly of organic monolayers and metal coordination at interfaces. The structure of the organic linker 2 was confirmed by single crystal X-ray diffraction analysis (XRD). On the densely packed Ag(111) surface, the terphenyl-4,4”-di(propiolonitrile) linkers self-assemble in a regular, molecular chevron arrangement exhibiting a Moire pattern. After the exposure of the molecular monolayer to a beam of Gd atoms, the propiolonitrile groups get readily involved in metal-ligand coordination interactions. Distinct coordination motifs evolve with coordination numbers varying between three and six for the laterally-bound Gd centers. The linker molecules retain an overall flat adsorption geometry. However, only networks with restricted local order were obtained, in marked contrast to previously employed, simpler polyphenylene-dicarbonitrile 1 linkers

    Human Herpesvirus 6 (HHV-6) Causes Severe Thymocyte Depletion in SCID-hu Thy/Liv Mice

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    Human herpesvirus 6 (HHV-6) is a potentially immunosuppressive agent that may act as a cofactor in the progression of AIDS. Here, we describe the first small animal model of HHV-6 infection. HHV-6 subgroup A, strain GS, efficiently infected the human thymic tissue implanted in SCID-hu Thy/Liv mice, leading to the destruction of the graft. Viral DNA was detected in Thy/Liv implants by quantitative polymerase chain reaction (PCR) as early as 4 d after inoculation and peaked at day 14. The productive nature of the infection was confirmed by electron microscopy and immunohistochemical staining. Atypical thymocytes with prominent nuclear inclusions were detected by histopathology. HHV-6 replication was associated with severe, progressive thymocyte depletion involving all major cellular subsets. However, intrathymic T progenitor cells (ITTPs) appeared to be more severely depleted than the other subpopulations, and a preferred tropism of HHV-6 for ITTPs was demonstrated by quantitative PCR on purified thymocyte subsets. These findings suggest that thymocyte depletion by HHV-6 may be due to infection and destruction of these immature T cell precursors. Similar results were obtained with strain PL-1, a primary isolate belonging to subgroup B. The severity of the lesions observed in this animal model underscores the possibility that HHV-6 may indeed be immunosuppressive in humans

    Exchange splitting of the three Γ¯ surface states of Ni(111) from three-dimensional spin- and angle-resolved photoemission spectroscopy

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    The valence-band electronic structure of a clean Ni(111) surface is investigated by spin-resolved photoemission. At room temperature the orientation of the photoelectron spins on the Bloch sphere and the exchange splitting of surface and bulk states along the surface normal (Γ̅ ) are determined. All investigated states are found to have a sizable exchange splitting >50 meV. Since the splitting is smaller than the intrinsic line width in the spin-integrated spectrum this is only seen with a spin-resolved technique. At room-temperature photoemission reaching above the Fermi level directly shows that the Shockley type surface state S1 has an occupied majority and an unoccupied minority band with a splitting ΔEex=62±15 meV. The surface states below the Fermi energy show a larger exchange splitting for in-plane hybridization [ΔEex(S3)=160 meV] than for out-of-plane hybridization [ΔEex(S2)=55 meV]

    Assessment of alcohol use among methadone maintenance patients by direct ethanol metabolites and self-reports

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    BACKGROUND: Heavy alcohol consumption may accelerate the progression of hepatitis C (HCV)-related liver disease and/or limit efforts at antiviral treatment. As most of the patients in methadone maintenance treatment (MMT) suffer from hepatitis C infection, this study was conducted to identify the alcohol intake among these patients at a Swiss Psychiatric University Clinic by self-reports and direct ethanol metabolites as biomarkers of ethanol consumption. PATIENTS AND METHODS: A convenience sample of 40 MMT patients (15 women, 25 men; median age 39 years) of the total 124 patients was asked and consented to participate in this study. This sample was not different in age, gender distribution, and rate of hepatitis C infection from the total sample. The Alcohol Use Disorders Identification Test (AUDIT) and self-reported ethanol intake during the previous 7 days were assessed. In addition, ethyl glucuronide (EtG) in urine, and fatty acid ethyl esters (FAEEs) and EtG in hair were determined using LC-MS/MS and gas chromatograph/mass spectrometer. The limit of quantitation for UEtG, HEtG, and FAEEs were 0.1 mg/l, 2.3 pg/mg, and 0.1 ng/mg, respectively. RESULTS: Fourteen participants reported abstinence from alcohol for the previous 7 days. AUDIT scores were > or =8 in 15 male and >5 in 5 female participants. Direct ethanol metabolites were as follows (median, min, max, standard deviation): UEtG (19 positives; 9.91, 1.38 to 251, 62.39 mg/l); the values of HEtG were 17.65, 0 to 513, 105.62 pg/mg [in 2 cases no material, 8 abstinent (up to 7 pg/mg), 15 social drinkers (up to 50 g per day), and 15 excessive users (>50/60 g/d)]. For the 13 cases, where enough material for additional determination of HFAEEs was available, the values were 0.32, 0 to 1.32, 0.44 ng/mg. Among the 30 HEtG-positive participants, 20 had not reported the corresponding ethanol intake using question 1 (frequency) and 2 (quantity) of the AUDIT. Of the 14 participants reporting no alcohol intake during the previous 7 days, 4 were UEtG-positive. HEtG and AUDIT correlated significantly (r = 0.622, p < 0.0001), but this was not the case for UEtG and self-reported ethanol intake during the previous 7 days. CONCLUSION: (1) HEtG identified 20 cases of daily ethanol intake of more than 20 g, that would have been missed by the sole use of question 1 (frequency) and 2 (quantity) of the AUDIT. (2) Using the total score of the AUDIT, HEtG confirmed 10 more cases positive for alcohol intake. (3) Episodic heavy drinking is with 22.5% more frequent than in general population, and (4) of the 14 participants who reported no alcohol intake during the previous 7 days, 4 were UEtG positive. Improved detection of alcohol consumption, which is hazardous or harmful in the context of HCV and opiate dependence, would allow for earlier intervention in this population which is at particular risk of liver disease and fatal respiratory-depressed overdose. The combined use of self-reports and direct ethanol metabolites seems promising
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