375 research outputs found
Investigation of the role of neutron transfer in the fusion of 32,34S with 197Au,208Pb using quasi-elastic scattering
Excitation functions for quasi-elastic scattering have been measured at
backward angles for the systems 32,34S+197Au and 32,34S+208Pb for energies
spanning the Coulomb barrier. Representative distributions, sensitive to the
low energy part of the fusion barrier distribution, have been extracted from
the data. For the fusion reactions of 32,34S with 197Au couplings related to
the nuclear structure of 197Au appear to be dominant in shaping the low energy
part of the barrier distibution. For the system 32S+208Pb the barrier
distribution is broader and extends further to lower energies, than in the case
of 34S+208Pb. This is consistent with the interpretation that the neutron
pick-up channels are energetically more favoured in the 32S induced reaction
and therefore couple more strongly to the relative motion. It may also be due
to the increased collectivity of 32S, when compared with 34S.Comment: 11 pages, 5 figure
Las pteridofitas de la provincia de Buenos Aires e Isla Martín García
En este trabajo nos hemos ocupado previamente en hacer una breve reseña organográfica de las Pteridofitas con claves sitemáticas desde la división hasta las especies, para abocarnos luego al estudio de estas últimas en particular.
En cada especie, figura la sinonomia, la descripción original y una descripción ampliada con los caracteres que presentan los ejemplares consultados.
A pesar de la fisonomía que presenta la región que nos ocupa, hemos podido constatar la presencia de cuatro Clases de las cinco que forman las Pteridofitas actuales distribuidas en 38 géneros y 64 especies.
Estas se hallan distribuidas principalmente en dos tipos de vegetación que no son los más característicos de la provincia de Buenos Aires; uno de ellos, la Pluviisilvae, cuya selva en galería constituye una formación que se extiende desde Punta Lara, hacia el norte en las márgenes del Paraná y Uruguay y sus afluentes e isla Martín García; y el otro, Rupideserta, que hallamos representado en las Sierras Bayas, Tandil y Ventana. En el resto de la provincia por el tipo de vegetación y por las modificaciones que ha sufrido por la acción del hombre, son muy pocas las especies que hallamos.
Cada especie ha sido ilustrada con dibujos y fotografías.In this paper we have dealt previously with a brief sketch on the organography of the Pheridophytes with systematic Keys from Division up to species, to settle down after on the study of the latter in particular.
With each species is the synonym, original description and an enlarged description with the characters that are present in the specimens consulted.
In spite of the physiography of the region, that we are dealing with, we have been able establish the presence of four classes of the five that form the actual Pteridophytes, distributed in 38 genera and 64 especies.
There are distributed mainly in two types of vegetation, which are the most characteristic in the province of Buenos Aires: one of these is Pluviisilvae, its forest in gallery presents a formation that ranges from Punta Lara toward the north on the margins of the Paraná River and Uruguay River and its tributaries and also on the Isle of Martín Garcia; the other formation is Rupideserta, which is represented in the Sierras Bayas, Tandil and Ventana.
The species we found in the remaining part of the province, were very few on account of the vegetation which is different and also because of the modifications that this suffered due to action of man.
Each species has been illustrated with drawings and photographs
The emergence of the cortisol circadian rhythm in monozygotic and dizygotic twin infants: the twin-pair synchrony
OBJECTIVE: Studies on the influence of genetic factors on the ontogeny of cortisol circadian rhythm in infants are lacking. This study evaluated the influence of twinning and the heritability on the age of emergence of salivary cortisol rhythm. DESIGN AND SUBJECTS: A longitudinal study was performed using salivary samples obtained during morning and night, at 2, 4, 8, 12, 16, 20 and 24 weeks of postnatal life in 34 infants, 10 monozygotic (MZ) and 7 dizygotic (DZ) twin pairs. Salivary cortisol was determined by radioimmunoassay (RIA). Zigosity was verified by DNA analysis of at least 13 short tandem repeat polymorphisms. Difference of the emergence of cortisol circadian rhythm, within each twin pair, the intraclass correlation coefficient and the heritability index (h(2)) were calculated. RESULTS: The mean (± SEM) age of emergence of salivary cortisol circadian rhythm was similar in MZ and DZ (7·8 ± 1·0 vs 7·4 ± 1·3 weeks). Seven pairs showed coincidence of the emergence of cortisol rhythm. Ten pairs were not coincident; among them the within-pair difference of emergence of salivary circadian rhythm was similar in both MZ and DZ groups. The intraclass correlation coefficients were rMZ = 0·60, P = 0·02; and rDZ = 0·65, P = 0·03, respectively. The heritability index (h(2)) was 0·21 (ns). CONCLUSIONS: Salivary circadian rhythm appeared at the same postnatal age in MZ and DZ twin infants. Although several physiological aspects might be involved, the heritability index, obtained in the present study, suggests less genetic than environmental impact on the age of the onset of the cortisol circadian rhythm. Our data also indicated that each twin-pair show synchrony because they probably shared prenatal and postnatal environmental synchronizers
Development of an Affimer-antibody combined immunological diagnosis kit for glypican-3
Glypican-3 (GPC3) is a promising new marker for hepatocellular carcinoma, but the reported values for serum GPC3 differ markedly between currently available kits. Here we isolated Affimer non-antibody binding proteins against GPC3 by phage display and developed a new sandwich chemiluminescence immunoassay (CLIA) combining an Affimer with a monoclonal antibody (Affimer-MAb CLIA). The proposed CLIA assay demonstrated a wide linear range 0.03–600 ng/mL) with a good linear correlation coefficient (0.9999), a high detection limitation (0.03 ng/mL) and specificity (0–0.002%) for detection of GPC3. The accuracy, hook effect and stability were demonstrated to be satisfactory. The mean level of GPC3 in serum was higher (>8.5 fold, P < 0.001) in hepatocellular carcinoma patients compared to healthy and other liver disease individuals. A poor correlation (correlation coefficients ranged from −0.286 to 0.478) was observed through pairwise comparison within different kits. However, only this newly developed CLIA test showed high specificity and correlated with the “gold standard” GPC3-immunohistochemistry. This study indicates that Affimer-MAb CLIA can be used to generate a sensitive immunodiagnostic kit, which offers the potential for a highly specific clinically-relevant detection system
Tunneling effects on impurity spectral function in coupled asymmetric quantum wires
The impurity spectral function is studied in coupled double quantum wires at
finite temperatures. Simple anisotropy in the confinement direction of the
wires leads to finite non-diagonal elements of the impurity spectral function
matrix. These non-diagonal elements are responsible for tunneling effects and
result in pronounced extra peak in the impurity spectral function up to
temperatures as high as 20 K.Comment: Accepted in Phys. Rev.
AFP, PIVKAII, GP3, SCCA-1 and follisatin as surveillance biomarkers for hepatocellular cancer in non-alcoholic and alcoholic fatty liver disease
<p>Abstract</p> <p>Background</p> <p>The incidence and mortality of hepatocellular cancer (HCC) complicating alcoholic and non-alcoholic fatty liver diseases (ALD and NAFLD) is rising in western societies. Despite knowing the at risk populations for HCC development, the lack of sensitive and specific means of surveillance hampers disease detection at curable stages. The most widely used serum HCC marker is alpha-fetoprotein (AFP), while PIVKA-II, glypican-3 (GP3) and Squamous Cell Carcinoma Antigen -1 (SCCA-1) have been proposed as new biomarkers. Assessment of these HCC biomarkers has largely been performed in patients with viral hepatitis. We conducted a cross sectional study assessing the value of these serum proteins, as well a novel candidate biomarker -follistatin – in patients with HCC arising on a background of ALD or NAFLD.</p> <p>Methods</p> <p>Pre-treatment serum samples from 50 patients with HCC arising on a background of ALD (n = 31) or NAFLD (n = 19) were assessed by specific ELISA assay for PIVKAII, Glypican-3, SCCA-1 and Follistatin. Results were compared and contrasted with a control patient group with biopsy proven steatohepatitis-related cirrhosis (n = 41). The diagnostic accuracy of each of the candidate biomarkers was evaluated using receiver operating characteristic (ROC) curve analysis, reporting the area under the curve (AUC) and its 95% confidence interval (CI). Performance was compared to that of the established biomarker, AFP.</p> <p>Results</p> <p>Serum levels of all proteins were assessed by specific ELISA assays. GP3, SCCA-1 and follistatin had no HCC surveillance benefit in these patients. AFP and PIVKAII were superior to the other markers, particularly in combination.</p> <p>Conclusion</p> <p>We conclude that while novel means of surveillance are urgently required, the combination of AFP and PIVKAII for HCC is an improvement on AFP alone in ALD/NAFLD patients. Furthermore, our data in this homogenous subset of patients- particularly that confirming no role for SCCA-1 – suggests that the choice of optimal biomarkers for HCC surveillance may be determined by the aetiology of underlying chronic liver disease.</p
Electrical parameters and water permeability properties of monolayers formed by T84 cells cultured on permeable supports
Attitudes Toward the Ethics of Research Using Social Media: A Systematic Review.
BACKGROUND: Although primarily used for social networking and often used for social support and dissemination, data on social media platforms are increasingly being used to facilitate research. However, the ethical challenges in conducting social media research remain of great concern. Although much debated in the literature, it is the views of the public that are most pertinent to inform future practice. OBJECTIVE: The aim of our study was to ascertain attitudes on the ethical considerations of using social media as a data source for research as expressed by social media users and researchers. METHODS: A systematic review was conducted, wherein 16 databases and 2 Internet search engines were searched in addition to handsearching, reference checking, citation searching, and contacting authors and experts. Studies that conducted any qualitative methods to collect data on attitudes on the ethical implications of research using social media were included. Quality assessment was conducted using the quality of reporting tool (QuaRT) and findings analyzed using inductive thematic synthesis. RESULTS: In total, 17 studies met the inclusion criteria. Attitudes varied from overly positive with people expressing the views about the essential nature of such research for the public good, to very concerned with views that social media research should not happen. Underlying reasons for this variation related to issues such as the purpose and quality of the research, the researcher affiliation, and the potential harms. The methods used to conduct the research were also important. Many respondents were positive about social media research while adding caveats such as the need for informed consent or use restricted to public platforms only. CONCLUSIONS: Many conflicting issues contribute to the complexity of good ethical practice in social media research. However, this should not deter researchers from conducting social media research. Each Internet research project requires an individual assessment of its own ethical issues. Guidelines on ethical conduct should be based on current evidence and standardized to avoid discrepancies between, and duplication across, different institutions, taking into consideration different jurisdictions
Association of newborn diseases with weight/length ratio and the adequacy of weight for gestational age
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