46,497 research outputs found
The Impact of Radiation and Chemotherapy on Outcomes in Two-staged Implant-Based Breast Reconstruction
No full textThe 56th Annual Medical Student Research Forum at UT Southwestern Medical Center (Tuesday, January 23, 2018, 2-5 p.m., D1.600)INTRODUCTION: Treatments for breast cancer include neoadjuvant chemotherapy (NACT), adjuvant chemotherapy (ACT), radiation (RAD), and combinations of these therapies. Many of these patients will choose to pursue implant-based breast reconstruction concurrently with these treatments. Effects of these therapies on the outcomes of implant-based reconstructions have not been studied fully.
METHODS: From January 2012 to December 2016 two surgeons performed 542 breast reconstructions using tissue expanders (TE). The number of patients choosing implants who completed reconstruction was n=272. They were split into 8 groups based on therapy received: Group 1 (no treatment, n=139), Group 2 (NACT, n=32), Group 3 (ACT, n=44), Group 4 (NACT+ACT, n=14), Group 5 (NACT+RAD, n=17), Group 6 (ACT+RAD, n=13), Group 7 (RAD, n=12), Group 8 (ACT+NACT+RAD, n=1). Group 8 was excluded because it had only one patient, leaving n=271. ANOVA (df between groups = 6, df within groups = 264) and Tukey HSD were run to compare differences in the percentages of patients with infections requiring IV antibiotics, necrosis requiring operation, seroma, and TE exchange for new TE. Numbers of different surgeries were also counted.
RESULTS: Comorbidities and age were equivalent across groups, except for Group 7 (55.7 yr) and Group 4 (41.6 yr), p=.03. There were no significant differences in percentages of patients with infection requiring IV antibiotics (p=.32), necrosis requiring operation (p=.09), or seroma (p=.40). For patients who required replacement of TE with another TE due to complication, only Group 1 (1.4%) vs Group 6 (15.4%) had a significant difference, p=.04.
There were no differences in the mean numbers of complication-related surgeries before implant placement (p=.07), complication-related surgeries after implant placement (p=.30), revision surgeries (p=.98), or total surgeries (p=.29). There were no significant differences in the percentages of patients receiving at least one complication-related surgery before implant (p=.16), at least one complication-related surgery after implant (p=.85), or at least one revision surgery (p=.94).
CONCLUSION: Among most patients who choose to undergo implant-based reconstruction in an academic practice, we found no significant differences in complication rates, mean numbers of surgeries per patient, and percentages of patients undergoing different types of surgeries. Although patients with combined adjuvant chemotherapy and radiation had a higher rate of TE exchange for new TE due to complication, the rates of other complications and surgeries were comparable. Given these results, practice trends in breast reconstruction can remain cautiously optimistic for patients choosing implant-based reconstruction concurrently with cancer treatments.Southwestern Medical Foundatio
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
Polarons induced electronic transport, dielectric relaxation and magnetodielectric coupling in spin frustrated Ba2FeWO6
No full textMixed valent double perovskite Ba2FeWO6, with tetragonal crystal structure, synthesized in a highly controlled reducing atmosphere, shows antiferromagnetic transition at T-N = 19 K. A cluster glass-like transition is observed around 30 K arising from the competing interactions between inhomogeneous magnetic states. The structural distortion leads to the formation of polarons that are not contributing to DC conduction below charge ordering temperature, T-co = 279 K. Above Tco, small polarons will start to hop by exploiting thermal energy and participate in the conduction mechanism. The polarons are also responsible for the dielectric relaxor behavior, in which the dielectric relaxation time follows non linearity in temperature as proposed by Fulcher. The material also exhibits a small room temperature magnetoresistance of 1.7% at 90 kOe. An intrinsic magnetodielectric coupling of similar to 4% near room temperature and at lower temperatures, as well as an extrinsic magnetodielectric coupling change from +4% to-6% at around 210K are reported. (C) 2015 Elsevier Ltd. All rights reserved
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
NMN adenylyltransferase and poly (ADP-Ribose) polymerase in bovine tissues and characterization of NMN adenylyltransferase from bull testis
No full textA 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
A 2 h periodic variation in the low-mass X-ray binary Ser X-1
No full textSpectroscopy of the low-mass X-ray binary Ser X-1 using the Gran Telescopio Canarias have revealed a ?2 h periodic variability that is present in the three strongest emission lines. We tentatively interpret this variability as due to orbital motion, making it the first indication of the orbital period of Ser X-1. Together with the fact that the emission lines are remarkably narrow, but still resolved, we show that a main-sequence K dwarf together with a canonical 1.4 M? neutron star gives a good description of the system. In this scenario, the most likely place for the emission lines to arise is the accretion disc, instead of a localized region in the binary (such as the irradiated surface or the stream-impact point), and their narrowness is due instead to the low inclination (?10°) of Ser X-1
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