46,571 research outputs found
Reply: Rapid changes in practice make analysis of historical databases irrelevant for contemporary counselling
No full textLive birth and perinatal outcomes following stimulated and unstimulated IVF: Analysis of over two decades of a nationwide data
No full textSTUDY QUESTION Does ovarian stimulation affect perinatal outcomes of preterm birth (PTB) and low birth weight (LBW) following IVF treatment. SUMMARY ANSWER Despite no significant differences in the risks of PTB and LBW between stimulated and unstimulated IVF in the present study, the study cannot exclude the effect of ovarian stimulation on the perinatal outcomes following IVF. WHAT IS ALREADY KNOWN Pregnancies resulting from assisted reproductive treatments (ART) are associated with a higher risk of pregnancy complications compared to spontaneously conceived pregnancies attributed to the underlying infertility and the in vitro fertilization techniques. It is of interest to determine the effect size of ovarian stimulation use in achieving a live birth and whether ovarian stimulation that is routinely used in IVF, affects perinatal outcomes of birth weight and gestational age at delivery compared to unstimulated IVF. STUDY DESIGN, SIZE, DURATION Anonymous data were obtained from the Human Fertilisation and Embryology Authority (HFEA), the statutory regulator of ART in the UK. The HFEA has collected data prospectively on all ART performed in the UK since 1991. Data from 1991 to 2011 comprising a total of 591 003 fresh IVF ± ICSI cycles involving 584 835 stimulated IVF cycles and 6168 unstimulated IVF cycles were analyzed. PARTICIPANTS/MATERIALS, SETTING, METHODS Data on all women undergoing either stimulated or unstimulated fresh IVF ± ICSI cycles during the period from 1991 to 2011 were analyzed to compare live birth rates, singleton live birth rates, perinatal outcomes of PTB, early PTB (<32 weeks), LBW and very LBW (<1500 grams) among singleton live births. Adjusted logistic regression was performed for each perinatal outcome for confounding factors: female age, period of treatment, cause of infertility, number of previous IVF cycles and previous live birth. MAIN RESULTS AND THE ROLE OF CHANCE Analysis of the large nationwide data demonstrated 3.5 times (95% confidence interval (CI): 3.1-3.9) as many unstimulated IVF cycles being required to achieve one live birth compared to stimulated IVF and 2.9 times (95% CI: 2.6-3.2) as many unstimulated IVF cycles being required to achieve one singleton live birth compared to stimulated IVF. There was no significant difference in the unadjusted odds for PTB (odds ratio (OR) 1.27, 95% CI: 0.80-2.00) and LBW (OR 1.48, 95% CI: 0.90-2.42) between stimulated and unstimulated IVF cycles. There was no significant difference in the risk of the adverse perinatal outcomes after adjusting for potential confounders; PTB (adjusted odds ratio (aOR) 1.43, 95% CI: 0.91-2.26) and LBW (aOR 1.58, 95% CI: 0.96-2.58). LIMITATIONS, REASONS FOR CAUTION Although the analysis was adjusted for a number of important confounders, the dataset had no information on smoking, body mass index (BMI) and the medical history of women during pregnancy to allow adjustment. Anonymized nature of the dataset did not make it permissible to analyse one cycle per woman. Given the smaller number of perinatal events with unstimulated IVF, a larger study is needed to investigate further. WIDER IMPLICATIONS OF THE FINDINGS Analysis of this large dataset demonstrates that ovarian stimulation has a vital role in maximizing efficacy of IVF. Although there were no significant differences for PTB and LBW following stimulated compared to unstimulated IVF, the CIs were wide enough to include possible clinically important effects. STUDY FUNDING/COMPETING INTEREST(S) No funding was obtained. There are no competing interests to declare
p-n Junction Formation in i-Ge Crystal by Laser Radiation
No full textP-n junction is the main component of many semiconductor devices. Thermodiffusion, ion implantation and molecular beam epitaxy are only a few methods to form a p-n junction. The main drawback for these methods is high cost per p-n junction since the equipment for these methods is expensive. A possibility of p-n junction formation by laser radiation was shown in several p- and n-type semiconductors: p-Si[1,2], p-CdTe[3], p-InSb[4,5], p-InAs[6], p-PbSe[7] and p-Ge[8] due to inversion of conductivity type. Unfortunately, the mechanism of p-n junction formation by laser radiation is not clear until now.
In the present research rectification effect of current-voltage characteristic in pure intrinsic Ge crystal after irradiation by Nd:YAG laser was observed. The effect is characterised by threshold intensity of the laser radiation. Increase of rectification ratio of current-voltage characteristics and barrier height with intensity of the laser radiation, energy of laser radiation quanta and number of pulses was observed in this experiment. The mechanism of this phenomenon is explained by generation and redistribution of intrinsic point defects in temperature gradient field, which causes strongly absorbed laser radiation. The redistribution of defects takes place because interstitial atoms drift towards the irradiated surface, but vacancies drift in the opposite direction – in the bulk of semiconductor according to Thermogradient effect. Since interstitials in Ge crystal are of n-type and vacancies are known to be of p-type, a p-n junction is formed.
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Acknowledgments.
The author gratefully acknowledges financial support in part by Europe Project in the Framework of MATERA+ project, European Regional Development Fund within the project “Sol-gel and laser technologies for the development of nanostructures and barrier structures”, the ESF Projects No. 1DP/1.1.1.2.0/09/ APIA/VIAA/142 and «Support for the implementation of doctoral studies at Riga Technical University»
Experimental investigation into the effect of substrate clamping on the piezoelectric behaviour of thick-film PZT elements
No full textThis paper details an experimental investigation of the clamping effect associated with thick-film piezoelectric elements printed on a substrate. The clamping effect reduces the measured piezoelectric coefficient, d33, of the film. This reduction is due to the influence of the d31 component in the film when a deformation of the structure occurs, by either the direct or indirect piezoelectric effect. Theoretical analysis shows a reduction in the measured d33 of 62%, i.e. a standard bulk lead zirconate titanate (PZT)-5H sample with a manufacturer specified d33 of 593pC/N would fall to 227.8pC/N. To confirm this effect, the d33 coefficients of five thin bulk PZT-5H samples of 220µm thickness were measured before and after their attachment to a metallized 96% alumina substrate. The experimental results show a reduction in d33 of 74% from 529pC/N to 139pC/N. The theoretical analysis was then applied to existing University of Southampton thick-film devices. It is estimated that the measured d33 value of 131pC/N of the thick-film devices is the equivalent of an unconstrained d33 of 345pC/N
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Trimebutine maleate as a multidimensional-antibacterial agent against functional dyspepsia: A prospective multicenter randomized, double-blind controlled trial
No full text[No Abstract Available]Galenica A.E. Pharmaceutical Company, GreeceJ. Kountouras: B. Research Grant (principal investigator, collaborator or consultant and pending grants as well as grants already received); Modest; This work has been financially supported by Galenica A.E. Pharmaceutical Company, Greece. E. Gavalas: None. A. Papaefthymiou: None. I. Tsechelidis: None. S. Polyzos: None. S. Bor: None. M. Diculescu: None. A. Bochenek: None. K. Jadallah: None. J. Rozciecha: None. T. Karakan: None. P. Dabrowski: None. M. Tadeusz: None. Z. Spirchez: None. O. Sezgin: None. M. Gulten: None. N. Farsakh: None. M. Doulberis: None
NMN adenylyltransferase and poly (ADP-Ribose) polymerase in bovine tissues and characterization of NMN adenylyltransferase from bull testis
No full textThe performance of the Elecsys® anti-Müllerian hormone assay in predicting extremes of ovarian response to corifollitropin alfa
No full textResearch question: What is the performance of anti-Müllerian hormone (AMH) as measured by the Elecsys® AMH assay in predicting ovarian response in women treated with 150 μg corifollitropin alfa (CFA)? Design: Multicentre, prospective study conducted between December 2015 and April 2018. Women were aged 18–43 years, had regular menstrual bleeding, a body mass index of 17–35 kg/m2 and weighed 60 kg or over. Exclusion criteria: previous oophorectomy, history of ovarian hyperstimulation syndrome, a previous IVF and intracytoplasmic sperm injection cycle producing over 30 follicles measuring 11 mm or wider, basal antral follicle count (AFC) over 20 or polycystic ovarian syndrome. All women were treated with 150 μg CFA followed by recombinant FSH (150–300 IU/day) in a fixed gonadotrophin releasing hormone antagonist protocol. Results: Of the 219 patients enrolled, 22.8% had low ovarian response (three or fewer oocytes), 66.2% had normal response and 11% had high ovarian response (15 or more oocytes). The AMH and AFC presented an area under the curve of 0.883 (95% CI 0.830 to 0.936) and 0.879 (95% CI 0.826 to 0.930), respectively, for low ovarian response; and an AUC of 0.865 (95% CI 0.793 to 0.935) and 0.822 (95% CI 0.734 to 0.909) for high ovarian response. An AMH cut-off of 1.0 ng/ml provided a sensitivity of 92.0% and a specificity of 66.9% in the prediction of low ovarian response; a cut-off of 2.25 ng/ml predicted high ovarian response with a sensitivity of 54.2% and a specificity of 91.8%. Conclusions: The automated Elecsys® AMH assay predicts ovarian response in a CFA antagonist protocol. The best predictors of ovarian response in CFA-treated patients were AMH and AFC
A note on the countable extensions of separable p\sp {\omega+n}-projective abelian -groups
No full textsummary:It is proved that if is a pure -projective subgroup of the separable abelian -group for such that , then is -projective as well. This generalizes results due to Irwin-Snabb-Cutler (CommentṀathU̇nivṠtṖauli, 1986) and the author (Arch. Math. (Brno), 2005)
THE ANOMALOUS FLUORESCENCE OF N,N-DIALKYL-P-CYANOANILINES
No full textPresent address of Omar S. Khalil: School of Chemistry, Rutgers University New Brunswick, New Jersey, 08903.Author Institution: Coates Chemical Laboratories, Louisiana State UniversityAbsorption and luminescence spectra of N,N-dialkyl-p-cyanoanilines in a variety of solvents are reported. Evidences for ``dimer” and ``excimer” formation are provided and the anomalous luminescences of these molecules, which exhibits three distinctly-different fluorescence emissions and two very dissimilar phosphorescence processes, are interpreted
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