1,629 research outputs found

    Anaesthetic challenging in microsurgical flap reconstruction: a systematic review

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    Background: Anaesthetic management for microvascular reconstructive surgery is challenging and clearly affects the risk of major complications such as flap hypo-perfusion. In this systematic review we explore recent (last 7 years) clinical evidences related to perioperative management and anaesthetic controversy of patients undergoing microvascular reconstructive surgery, especially focused on head and neck surgery with free flaps (FF) and breast reconstructive surgery with deep inferior epigastric perforator flap (DIEP-flap). Methods: A literature search of published clinical studies between 2011 and 2018 was conducted, yielding a total of 4307 papers. Only 150 were eligible, according inclusion and exclusion criteria. Results: 62 studies were selected for this review and categorized in 3 groups: preoperative-intraoperative- postoperative anaesthetic management and areas of controversy for patients undergoing head and neck surgery with FF and breast reconstructive surgery with DIEP-flap. Discussion: Anaesthetic management for flap reconstructive surgery remains an open field of interest with limited evidences regarding a standard care. Main components of research currently are: the need to join standard multidisciplinary enhanced recovery pathways, as well as the necessity to develop a standard intraoperative management. In theatre, the recent hemodynamic parameter “Hypotension Probability Indicator” (HPI) is promising: the advantage to predict a drop in the mean arterial pressure can be more effective than a fluid therapy titrated to maintain SVV less than 13%. Prospective studies are necessary to clarify

    Large-scale Bias and Efficient Generation of Initial Conditions for Non-Local Primordial Non-Gaussianity

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    We study the scale-dependence of halo bias in generic (non-local) primordial non-Gaussian (PNG) initial conditions of the type motivated by inflation, parametrized by an arbitrary quadratic kernel. We first show how to generate non-local PNG initial conditions with minimal overhead compared to local PNG models for a general class of primordial bispectra that can be written as linear combinations of separable templates. We run cosmological simulations for the local, and non-local equilateral and orthogonal models and present results on the scale-dependence of halo bias. We also derive a general formula for the Fourier-space bias using the peak-background split (PBS) in the context of the excursion set approach to halos and discuss the difference and similarities with the known corresponding result from local bias models. Our PBS bias formula generalizes previous results in the literature to include non-Markovian effects and non-universality of the mass function and are in better agreement with measurements in numerical simulations than previous results for a variety of halo masses, redshifts and halo definitions. We also derive for the first time quadratic bias results for arbitrary non-local PNG, and show that non-linear bias loops give small corrections at large-scales. The resulting well-behaved perturbation theory paves the way to constrain non-local PNG from measurements of the power spectrum and bispectrum in galaxy redshift surveys.Comment: 43 pages, 10 figures. v2: references added. 2LPT parallel code for generating non-local PNG initial conditions available at http://cosmo.nyu.edu/roman/2LP

    Allosteric modulators targeting cannabinoid cb1 and cb2 receptors: Implications for drug discovery

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    Allosteric modulators of cannabinoid receptors hold great therapeutic potential, as they do not possess intrinsic efficacy, but instead enhance or diminish the receptor's response of orthosteric ligands allowing for the tempering of cannabinoid receptor signaling without the desensitization, tolerance and dependence. Allosteric modulators of cannabinoid receptors have numerous advantages over the orthosteric ligands such as higher receptor type selectivity, probe dependence and biased signaling, so they have a great potential to separate the therapeutic benefits from side effects own of orthosteric ligands. This review aims to give an overview of the CB1 and CB2 receptor allosteric modulators highlighting the structure-activity relationship and pharmacological profile of each classes, and their future promise

    Medicinal Chemistry approach, pharmacology and neuroprotective benefits of CB2R modulators in neurodegenerative diseases

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    In the last decades, cannabinoid receptor 2 (CB2R) has continued to receive attention as a key therapeutic target in neuroprotection. Indeed, several findings highlight the neuroprotective effects of CB2R through suppression of both neuronal excitability and reactive microglia. Additionally, CB2R seems to be a more promising target than cannabinoid receptor 1 (CB1R) thanks to the lack of central side effects, its lower expression levels in the central nervous system (CNS), and its inducibility, since its expression enhances quickly in the brain following pathological conditions. This review aims to provide a thorough overview of the main natural and synthetic selective CB2R modulators, their chemical classification and their potential therapeutic usefulness in neuroprotection, a crucial aspect for the treatment of neurodegenerative diseases

    COLA with scale-dependent growth: applications to screened modified gravity models

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    We present a general parallelized and easy-to-use code to perform numerical simulations of structure formation using the COLA (COmoving Lagrangian Acceleration) method for cosmological models that exhibit scale-dependent growth at the level of first and second order Lagrangian perturbation theory. For modified gravity theories we also include screening using a fast approximate method that covers all the main examples of screening mechanisms in the literature. We test the code by comparing it to full simulations of two popular modified gravity models, namely f(R) gravity and nDGP, and find good agreement in the modified gravity boost-factors relative to ΛCDM even when using a fairly small number of COLA time steps

    On virialization with dark energy

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    We review the inclusion of dark energy into the formalism of spherical collapse, and the virialization of a two-component system, made of matter and dark energy. We compare two approaches in previous studies. The first assumes that only the matter component virializes, e.g. as in the case of a classic cosmological constant. The second approach allows the full system to virialize as a whole. We show that the two approaches give fundamentally different results for the final state of the system. This might be a signature discriminating between the classic cosmological constant which cannot virialize and a dynamical dark energy mimicking a cosmological constant. This signature is independent of the measured value of the equation of state. An additional issue which we address is energy non-conservation of the system, which originates from the homogeneity assumption for the dark energy. We propose a way to take this energy loss into account.Comment: 15 pages, 5 figures. Accepted for publication in JCA

    Desempenho produtivo e características de carcaça de cabritos alimentados com diferentes proporções de concentrado.

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    O objetivo do presente estudo foi avaliar o desempenho produtivo e as características da carcaça de cabritos alimentados com quatro relações de concentrado e volumoso nas rações, tendo como volumoso o capim Elefante in natura picado. As proporções avaliadas foram: 80:20%; 60:40%; 40:60% e 20:80% de con-centrado e volumoso na matéria seca das rações. Foram utilizados 28 caprinos, machos, não castrados, da raça Saanen com peso corporal inicial médio de 9,3 kg distribuídos em quatro lotes de sete animais mantidos em baias coletivas. O delineamento experimental adotado foi o inteiramente casualizado com sete repetições. O aumento nas proporções de concentrado das rações proporcionou maiores pesos corporais finais, os ganhos de peso totais. Além disso, também foram obtidos maiores pesos e rendimentos de carcaça com as maiores doses de concentrado. Assim, tecnicamente é viável o uso de rações com elevado teor de concentrado para caprinos visando a terminação dos mesmos, porém a dose a ser utilizada deverá ser condicionada também em função do desempenho bioeconômico promovido pela suplementação

    A Consistent Comparison of Bias Models using Observational Data

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    We investigate five different models for the dark matter halo bias, ie., the ratio of the fluctuations of mass tracers to those of the underlying mass, by comparing their cosmological evolution using optical QSO and galaxy bias data at different redshifts, consistently scaled to the WMAP7 cosmology. Under the assumption that each halo hosts one extragalactic mass tracer, we use a χ2\chi^2 minimization procedure to determine the free parameters of the bias models as well as to statistically quantify their ability to represent the observational data. Using the Akaike information criterion we find that the model that represents best the observational data is the Basilakos & Plionis (2001; 2003) model with the tracer merger extension of Basilakos, Plionis & Ragone-Figueroa (2008) model. The only other statistically equivalent model, as indicated by the same criterion, is the Tinker et al. (2010) model. Finally, we find an average, over the different models, dark matter halo mass that hosts optical QSOs of: Mh2.7(±0.6)×1012h1MM_h\simeq 2.7 (\pm 0.6) \times 10^{12} h^{-1} M_{\odot}, while the corresponding value for optical galaxies is: Mh6.3(±2.1)×1011h1MM_h\simeq 6.3 (\pm 2.1) \times 10^{11} h^{-1} M_{\odot}.Comment: MNRAS in press, 12 pages, 6 color figures, 4 table
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