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  • 1
    Electronic Resource
    Electronic Resource
    Arsenic passivation of InP surface for metal-insulator-semiconductor devices based on both ultra-high vacuum technique and chemical procedure (1987)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 61 (1987), S. 257-260 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Two passivation treatments of InP surface are presented: (i) thermal treatment under an arsenic partial pressure by molecular-beam epitaxy technique, and (ii) a new As-based aqueous chemical treatment. Both result in similarly improved electronic and physicochemical properties of the InP surface. The fast interface state density is reduced, the drift phenomena are practically suppressed and the thermal stability is greatly enhanced.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.338867
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  • 2
    Electronic Resource
    Electronic Resource
    Electronical properties of metal-insulator-semiconductor devices prepared on thermally treated InP in phosphorus overpressure (1986)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 60 (1986), S. 2191-2193 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effect of excess phosphorus vapor during the process of MIS structures on InP is analyzed in detail. It is shown that the density of interface state distribution is considerably modified after in situ thermal precleaning of the substrate in phosphorus overpressure (suppression of the Fermi-level pinning and significant reduction of the density of surface states near midgap). Phosphorus overpressure also provides an efficient protection of the surface during the insulator deposition. Fermi-level pinning in the upper part of the gap is assigned to the uncontrolled native oxide left on the surface after a stay of InP substrate in ambient atmosphere.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.337177
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Combined treatment with zidovudine and lymphoblast interferon-alpha in patients with HIV-related Kaposi's sarcoma (1991)
    Springer
    Journal of molecular medicine 69 (1991), S. 360-367 
    Details
    ISSN: 1432-1440
    Keywords: Kaposi's sarcoma ; Interferon-alpha ; Zidovudine ; Combination therapy ; HIV antigenemia ; Bone marrow suppression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A combination of oral zidovudine (250 mg twice daily) and subcutaneous interferon-alpha (10×106 units daily) was evaluated for clinical, antiretroviral, and immunological efficacy and for side effects in 17 patients with AIDS-related Kaposi's sarcoma. Fifteen patients were evaluable. During the study period of 12 weeks, tumor responses were complete in two patients and partial in two patients (27% major response rate). Minimal responses were seen in two patients (40% overall response rate). An anti-HIV effect (reduction of serum p24 antigen by 70% or more) was observed in seven of ten evaluable patients who were initially antigenemic. CD4 lymphocyte counts remained unchanged. In six patients who had either a tumor response or a marked decline of HIV antigenemia, the treatment was continued between 12 and 59 weeks beyond the study period. Two of four patients with tumor regression at 12 weeks had an additional tumor response in this period despite prior dose reduction of interferon due to toxicity. Late progression of KS was eventually observed in four of six patients on prolonged treatment. The responsiveness of Kaposi's sarcoma seen in this study in patients with low CD4 counts and prior constitutional symptoms (fever, weight loss) was unexpected and needs further confirmation by larger patient groups. Dose-limiting toxicities were bone marrow depression (severe anemia in four and neutropenia with anemia in two patients), subjective adverse experiences (fever, fatigue, myalgia; four patients) and both (two patients). Adjustment of the interferon dose improved the subjective as well as the hematologic tolerance to the combined treatment. Thus, the combination of zidovudine and interferon-alpha can be considered as a possible treatment of AIDS-related Kaposi's sarcoma. However, its use may be limited by toxicity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02115785
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  • 4
    Electronic Resource
    Electronic Resource
    Correlation between in vitro susceptibility ofCandida albicans and fluconazole-resistant oropharyngeal candidiasis in HIV-infected patients (1993)
    Springer
    European journal of clinical microbiology & infectious diseases 12 (1993), S. 911-915 
    Details
    ISSN: 1435-4373
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Twenty-five patients seen consecutively at an HIV outpatient clinic who had clinical evidence of oropharyngeal candidiasis and two or more oral swabs positive for yeasts on culture were studied retrospectively. For each of the 65 isolates susceptibility to fluconazole was evaluated by the disk diffusion test and determination of the minimal inhibitory concentration (MIC). A correlation was sought between clinical resistance and in vitro susceptibility data. Seven patients were non-responders and 19 were responders (one patient figuring in both groups). Significant differences were observed between the two groups with respect to the median interval after the diagnosis of AIDS (27 months in non-responders and 2 months in responders; p=0.001), the median CD4+ cell count (6 and 21 cells/mm3 respectively; p=0.005) and the median number of previous episodes of oropharyngeal candidiasis treated with fluconazole (13 and 2 episodes respectively; p=0.001).Candida albicans was identified in 64 of 65 cultures. The correlation between MIC values and diameters of inhibition was good (r=0.85; p〈0.001). The degree of in vitro susceptibility of the isolates to fluconazole showed a significant difference between non-responders and responders (mean inhibition diameters 13 and 36 mm respectively; p〈0.001) with a tentative cut-off value of 25 mm. An advanced stage of HIV infection and previous exposure to fluconazole could be risk factors for the development of fluconazole-resistant oropharyngeal candidiasis.Candida albicans strains with decreased in vitro susceptibility to fluconazole were responsible for the clinical resistance which could be predicted by a simple disk diffusion test.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01992164
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  • 5
    Electronic Resource
    Electronic Resource
    Prevalence of latent toxoplasmosis and serological diagnosis of active infection in HIV-positive patients (1993)
    Springer
    European journal of clinical microbiology & infectious diseases 12 (1993), S. 591-595 
    Details
    ISSN: 1435-4373
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The seroprevalence of latentToxoplasma gondii infection was determined in a cohort of 715 HIV-positive patients followed up at an HIV outpatient clinic. Using indirect immunofluorescence and direct agglutination assays for detecting IgG, the prevalence of anti-Toxoplasma gondii antibodies was shown to be 50 %. During a four-year period, clinically apparent acute toxoplasmosis occurred in 47 patients (43 with cerebral, 3 with ocular and 1 with bone marrow toxoplasmosis) among the 360 patients positive for anti-Toxoplasma gondii IgG and in one patient (with cerebral toxoplasmosis) among the 355 patients who were serologically negative. A significant rise in IgG levels could be shown during acute toxoplasmosis episodes in only 30 % of patients, compared with 3 % of patients without active toxoplasmosis. During acute toxoplasmosis, IgM antibodies were detected in only two patients (6 %) by an immunosorbent agglutination assay and in one (3 %) by an enzymatic immunocapture assay. Specific IgA was detected by a non-enzymatic immunocapture assay in six patients (18 %) during acute episodes. The very high predictive value (99.7 %) of a negative IgG test remains the best serological parameter for excluding an acute episode of toxoplasmosis in HIV-positive patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01973636
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  • 6
    Electronic Resource
    Electronic Resource
    Diagnosis of pulmonary infections in patients infected with the human immunodeficiency virus (1989)
    Springer
    European journal of clinical microbiology & infectious diseases 8 (1989), S. 123-126 
    Details
    ISSN: 1435-4373
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Over a three-year period, 54 episodes of pneumonia were diagnosed in 45 adults infected with the human immunodeficiency virus (HIV). These episodes were reviewed in order to assess the distribution of pathogens and their clinical presentation. Thirty-six episodes were due to an opportunistic pathogen (Pneumocystis carinii in 31,Mycobacterium avium complex in 3,Mycobacterium tuberculosis in 2), and 18 were caused by non-opportunistic pathogens (11Streptococcus pneumoniae, 2Haemophilus influenzae, 5 unknown pathogens that responded to broad-spectrum antibiotics). Non-opportunistic pneumonias were characterized by an abrupt onset (18/18 had pulmonary symptoms of 〈 7 days duration), high fever (13/18), and focal lung infiltrates (17/18). In contrast, opportunistic infections infrequently presented with pulmonary symptoms of 〈 7 days duration (3/36) or high fever (7/36), and most of the chest radiograms (34/36) disclosed a diffuse lung infiltrate. In HIV-infected patients presenting with pneumonia, simple clinical and radiological data may point to bacterial pathogens. Such data could be used in selected cases to spare invasive procedures and to start empirical antibiotic therapy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01963894
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    Paper (German National Licenses)
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  • 7
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    Habitat specialization and phylogenetic structure of tree species in a coastal Brazilian white-sand forest (2014)
    Oxford University Press
    Details
    Publication Date: 2014-03-28
    Description: Aims The coastal Brazilian rainforest on white-sand (restinga) ranks among the most fragmented forest types in the tropics, owing to both the patchy distribution of sandy soils and widespread coastal development activities. Here we study the environmental and evolutionary determinants of a forest tree assemblage at a single restinga forest in Southeastern Brazil. We also explore the ability of competing hypotheses to explain the maintenance of species diversity in this forest type, which includes contrasting extremes of edaphic conditions associated with flooding stress. Methods The study was conducted in a white-sand forest permanent plot of 10.24 ha on the coastal plain of Southeastern Brazil. This plot was divided into 256 quadrats of 20 x 20 m, which were classified into two main edaphic habitats (flooded and drained). Trees with a diameter ≥1cm at breast height were identified. We assembled DNA sequence data for each of the 116 morphospecies recognized using two chloroplast markers ( rbcL and matK ). A phylogenetic tree was obtained using the maximum likelihood method, and a phylogenetic distance matrix was produced from an ultrametric tree. We analyzed similarity in floristic composition and structure between habitats and related them to cross-plot distances using permutation procedures. Null model torus shift simulations were performed to obtain a statistical significance level for habitat association for each species. The phylogenetic structure for the two habitats and for each 20 x 20 m quadrat was calculated using the mean phylogenetic distance weighted by species abundance and checked for significance using the standardized effect size generated by 5000 randomizations of phylogenetic tip labels. Important Findings Our results indicate that partitioning among edaphic habitats is important for explaining species distributions and coexistence in restinga forests. Species distributions within the plot were found to be non-random: there was greater floristic similarity within than between habitats, and 〉40% of the more abundant species were positively or negatively associated with at least one habitat. Patterns of habitat association were not independent of phylogenetic relatedness: the community was overdispersed with respect to space and habitat type. Closely related species tended to occur in different habitats, while neighboring trees tended to belong to more distantly related species. We conclude that habitat specialization is important for the coexistence of species in restinga forests and that habitat heterogeneity is therefore an essential factor in explaining the maintenance of diversity of this unique but fragile and threatened type of forest.
    Print ISSN: 1752-993X
    Electronic ISSN: 1752-9921
    Topics: Biology
    Published by Oxford University Press
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    PAPER CURRENT
  • 8
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    Simulating long-term response of tropical wet forests to fragmentation (2003)
    In:  EPIC3Ecosystems, 6(2), pp. 114-128
    Details
    Publication Date: 2019-07-17
    Description: In the coming decades, a large fraction of the tropical rainforests will be fragmented into remnants surrounded by secondaryvegetation, land-used areas, or roads. It is important to developintegrative tools to monitor the evolution of these fragmentedecosystems. We used the individual-oriented and process-basedforest growth simulator Formind to investigate the spatial andtemporal effects of various intensities and patterns offragmentation within a forest landscape, on standing biomass andfunctional diversity. The simulator was calibrated for anold-growth rain forest in French Guiana, South America. We foundthat the standing biomass of forest remnants was reducedsignificantly compared to a similar area of non fragmented forest.When fewer but large remnants were created rather than many smallones, the total loss in biomass and the increase in the abundanceof early successional species were significantly reduced,confirming that edge effects dominate the functioning of forestremnants. We also performed simulations of secondary successionafter the landscape had been abandoned. The simulated recoverytime in those secondary forests depends on both the size ofcleared area and on the spatial pattern of the remnant forests.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
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  • 9
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    Hyperdominance in the Amazonian tree flora (2013)
    In:  Science vol. 342 no. 124309
    Details
    Publication Date: 2024-04-18
    Description: The vast extent of the Amazon Basin has historically restricted the study of its tree communities to the local and regional scales. Here, we provide empirical data on the commonness, rarity, and richness of lowland tree species across the entire Amazon Basin and Guiana Shield (Amazonia), collected in 1170 tree plots in all major forest types. Extrapolations suggest that Amazonia harbors roughly 16,000 tree species, of which just 227 (1.4%) account for half of all trees. Most of these are habitat specialists and only dominant in one or two regions of the basin. We discuss some implications of the finding that a small group of species—less diverse than the North American tree flora—accounts for half of the world’s most diverse tree community.
    Keywords: hyperdominance ; Amazonia ; Amazon Basin ; Guiana Shield ; trees ; commonness ; rarity ; richness ; tree species
    Repository Name: National Museum of Natural History, Netherlands
    Type: info:eu-repo/semantics/article
    Format: application/pdf
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  • 10
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    Global transpiration data from sap flow measurements: the SAPFLUXNET database (2021)
    In:  Earth System Science Data
    Details
    Publication Date: 2021-07-07
    Description: Plant transpiration links physiological responses of vegetation to water supply and demand with hydrological, energy, and carbon budgets at the land–atmosphere interface. However, despite being the main land evaporative flux at the global scale, transpiration and its response to environmental drivers are currently not well constrained by observations. Here we introduce the first global compilation of whole-plant transpiration data from sap flow measurements (SAPFLUXNET, https://sapfluxnet.creaf.cat/, last access: 8 June 2021). We harmonized and quality-controlled individual datasets supplied by contributors worldwide in a semi-automatic data workflow implemented in the R programming language. Datasets include sub-daily time series of sap flow and hydrometeorological drivers for one or more growing seasons, as well as metadata on the stand characteristics, plant attributes, and technical details of the measurements. SAPFLUXNET contains 202 globally distributed datasets with sap flow time series for 2714 plants, mostly trees, of 174 species. SAPFLUXNET has a broad bioclimatic coverage, with woodland/shrubland and temperate forest biomes especially well represented (80 % of the datasets). The measurements cover a wide variety of stand structural characteristics and plant sizes. The datasets encompass the period between 1995 and 2018, with 50 % of the datasets being at least 3 years long. Accompanying radiation and vapour pressure deficit data are available for most of the datasets, while on-site soil water content is available for 56 % of the datasets. Many datasets contain data for species that make up 90 % or more of the total stand basal area, allowing the estimation of stand transpiration in diverse ecological settings. SAPFLUXNET adds to existing plant trait datasets, ecosystem flux networks, and remote sensing products to help increase our understanding of plant water use, plant responses to drought, and ecohydrological processes. SAPFLUXNET version 0.1.5 is freely available from the Zenodo repository (https://doi.org/10.5281/zenodo.3971689; Poyatos et al., 2020a). The “sapfluxnetr” R package – designed to access, visualize, and process SAPFLUXNET data – is available from CRAN.
    Type: info:eu-repo/semantics/article
    Format: application/pdf
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