461 research outputs found

    A systematic review comparing the functional changes and complications of DIEP and TRAM flaps in patients receiving breast reconstruction

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    Aim: Treatment for breast cancer may involve unilateral or bilateral mastectomy, with subsequent breast reconstruction surgery. Using autologous tissue flaps during reconstructive surgery is increasingly popular. The aim of this systematic review was to determine if the DIEP flap is more effective than the TRAM flap for breast reconstruction in females after a mastectomy in terms of donor site morbidity, recipient site morbidity, and functional outcome. Methods: Studies were identified using the databases Medline and Embase and applying predefined search criteria. The limits applied were; peer-reviewed, published between January 1980 to May 2013, human trials, English language. Study inclusion followed a review of the title, abstract, and full text by two independent researchers. Results: Two trends were identified. 1) DIEP flap surgery reduces the risk of abdominal weakness without increasing the risk of flap complications if performed by a surgeon well trained in microsurgery; 2) TRAM flap surgery remains a good alternative due to its evolution towards muscle-sparing techniques. Conclusion: This appears to be the first systematic review in this area of research. The evidence demonstrates that DIEP flap reduces postoperative abdominal morbidity, with no increased flap complication compared to the TRAM flap if performed by a surgeon well trained in microsurgery

    Scalar perturbation spectra from warm inflation

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    We present a numerical integration of the cosmological scalar perturbation equations in warm inflation. The initial conditions are provided by a discussion of the thermal fluctuations of an inflaton field and thermal radiation using a combination of thermal field theory and thermodynamics. The perturbation equations include the effects of a damping coefficient Γ\Gamma and a thermodynamic potential VV. We give an analytic expression for the spectral index of scalar fluctuations in terms of a new slow-roll parameter constructed from Γ\Gamma. A series of toy models, inspired by spontaneous symmetry breaking and a known form of the damping coefficient, lead to a spectrum with ns>1n_s>1 on large scales and ns<1n_s<1 on small scales.Comment: 12 pages, 5 figures, RevTeX 4, revised with extra figure

    Thermal correction to the Casimir force, radiative heat transfer, and an experiment

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    The low-temperature asymptotic expressions for the Casimir interaction between two real metals described by Leontovich surface impedance are obtained in the framework of thermal quantum field theory. It is shown that the Casimir entropy computed using the impedance of infrared optics vanishes in the limit of zero temperature. By contrast, the Casimir entropy computed using the impedance of the Drude model attains at zero temperature a positive value which depends on the parameters of a system, i.e., the Nernst heat theorem is violated. Thus, the impedance of infrared optics withstands the thermodynamic test, whereas the impedance of the Drude model does not. We also perform a phenomenological analysis of the thermal Casimir force and of the radiative heat transfer through a vacuum gap between real metal plates. The characterization of a metal by means of the Leontovich impedance of the Drude model is shown to be inconsistent with experiment at separations of a few hundred nanometers. A modification of the impedance of infrared optics is suggested taking into account relaxation processes. The power of radiative heat transfer predicted from this impedance is several times less than previous predictions due to different contributions from the transverse electric evanescent waves. The physical meaning of low frequencies in the Lifshitz formula is discussed. It is concluded that new measurements of radiative heat transfer are required to find out the adequate description of a metal in the theory of electromagnetic fluctuations.Comment: 19 pages, 4 figures. svjour.cls is used, to appear in Eur. Phys. J.

    Toward an internally consistent astronomical distance scale

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    Accurate astronomical distance determination is crucial for all fields in astrophysics, from Galactic to cosmological scales. Despite, or perhaps because of, significant efforts to determine accurate distances, using a wide range of methods, tracers, and techniques, an internally consistent astronomical distance framework has not yet been established. We review current efforts to homogenize the Local Group's distance framework, with particular emphasis on the potential of RR Lyrae stars as distance indicators, and attempt to extend this in an internally consistent manner to cosmological distances. Calibration based on Type Ia supernovae and distance determinations based on gravitational lensing represent particularly promising approaches. We provide a positive outlook to improvements to the status quo expected from future surveys, missions, and facilities. Astronomical distance determination has clearly reached maturity and near-consistency.Comment: Review article, 59 pages (4 figures); Space Science Reviews, in press (chapter 8 of a special collection resulting from the May 2016 ISSI-BJ workshop on Astronomical Distance Determination in the Space Age

    Causes of death in a contemporary cohort of patients with type 2 diabetes and atherosclerotic cardiovascular disease: Insights from the TECOS trial

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    Objective: We evaluated the specific causes of death and their associated risk factors in a contemporary cohort of patients with type 2 diabetes and atherosclerotic cardiovascular disease (ASCVD). Research Design and Methods: We used data from the Trial Evaluating Cardiovascular Outcomes with Sitagliptin (TECOS) study (n = 14,671), a cardiovascular (CV) safety trial adding sitagliptin versus placebo to usual care in patients with type 2 diabetes and ASCVD (median follow-up 3 years). An independent committee blinded to treatment assignment adjudicated each cause of death. Cox proportional hazards models were used to identify risk factors associated with each outcome. Results: A total of 1,084 deaths were adjudicated as the following: 530 CV (1.2/100 patientyears [PY], 49% of deaths), 338 non-CV (0.77/100 PY, 31% of deaths), and 216 unknown (0.49/100 PY, 20% of deaths). Themost common CV death was sudden death (n = 145, 27% of CV death) followed by acute myocardial infarction (MI)/stroke (n = 113 [MI n = 48, stroke n = 65], 21% of CV death) and heart failure (HF) (n = 63, 12% of CV death). Themost common non-CV deathwas malignancy (n = 154, 46% of non-CV death). The risk of specific CV death subcategories was lower among patients with no baseline history of HF, including sudden death (hazard ratio [HR] 0.4; P = 0.0036), MI/stroke death (HR 0.47; P = 0.049), and HF death (HR 0.29; P = 0.0057). Conclusions: In this analysis of a contemporary cohort of patients with diabetes and ASCVD, sudden death was the most common subcategory of CV death. HF prevention may represent an avenue to reduce the risk of specific CV death subcategories

    Treatment Outcomes of Patients With Multidrug-Resistant and Extensively Drug-Resistant Tuberculosis According to Drug Susceptibility Testing to First- and Second-line Drugs: An Individual Patient Data Meta-analysis

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    The clinical validity of drug susceptibility testing (DST) for pyrazinamide, ethambutol, and second-line antituberculosis drugs is uncertain. In an individual patient data meta-analysis of 8955 patients with confirmed multidrug-resistant tuberculosis, DST results for these drugs were associated with treatment outcome
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