413 research outputs found
Physics of Trans-Planckian Gravity
We study the field theoretical description of a generic theory of gravity
flowing to Einstein General Relativity in IR. We prove that, if ghost-free, in
the weakly coupled regime such a theory can never become weaker than General
Relativity. Using this fact, as a byproduct, we suggest that in a ghost-free
theory of gravity trans-Planckian propagating quantum degrees of freedom cannot
exist. The only physical meaning of a trans-Planckian pole is the one of a
classical state (Black Hole) which is described by the light IR quantum degrees
of freedom and gives exponentially-suppressed contributions to virtual
processes. In this picture Einstein gravity is UV self-complete, although not
Wilsonian, and sub-Planckian distances are unobservable in any healthy theory
of gravity. We then finally show that this UV/IR correspondence puts a severe
constraint on any attempt of conventional Wilsonian UV-completion of
trans-Planckian gravity. Specifically, there is no well-defined energy domain
in which gravity could become asymptotically weak or safe.Comment: 23 pages, 4 figures, v2: Paper reorganized to improve clarity;
additional explanations and references added; version accepted for
publication in Phys. Rev.
Consistent Nest Site Selection by Turtles Across Habitats With Varying Levels of Human Disturbance
Human disturbance impacts the breeding behavior of many species, and it is particularly important to understand how these human-caused changes affect vulnerable taxa, such as turtles. Habitat alteration can change the amount and quality of suitable nesting habitat, while human presence during nesting may influence nesting behavior. Consequently, both habitat alteration and human presence can influence the microhabitat that females choose for nesting. In the summer of 2019, we located emydid turtle nests in east-central Alabama, USA, in areas with varying levels of human disturbance (high, intermediate, low). We aimed to determine whether turtles selected nest sites based on a range of microhabitat variables comparing maternally selected natural nests to randomly chosen artificial nests. We also compared nest site choice across areas with different levels of human disturbance. Natural nests had less variance in canopy openness and average daily mean and minimum temperature than artificial nests, but microhabitat variables were similar across differing levels of disturbance. Additionally, we experimentally quantified nest predation across a natural to human-disturbed gradient. Nest predation rates were higher in areas with low and intermediate levels of disturbance than in areas with high human disturbance. Overall, these results show that turtles are not adjusting their choices of nest microhabitat when faced with anthropogenic change, suggesting that preserving certain natural microhabitat features will be critical for populations in human-disturbed areas
Effects of interrupting prolonged sitting with physical activity breaks on blood glucose, insulin and triacylglycerol measures : a systematic review and meta-analysis
Abstract: Background: Physical activity (PA) breaks in sitting time might attenuate metabolic markers relevant to the prevention of type 2 diabetes. Objectives: The primary aim of this paper was to systematically review and meta-analyse trials that compared the effects of breaking up prolonged sitting with bouts of PA throughout the day (INT) versus continuous sitting (SIT) on glucose, insulin and triacylglycerol (TAG) measures. A second aim was to compare the effects of INT versus continuous exercise (EX) on glucose, insulin and TAG measures. Methods: The review followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) recommendations. Eligibility criteria consisted of trials comparing INT vs. SIT or INT vs. one bout of EX before or after sitting, in participants aged 18 or above, who were classified as either metabolically healthy or impaired, but not with other major health conditions such as chronic obstructive pulmonary disease or peripheral arterial disease. Results: A total of 42 studies were included in the overall review, whereas a total of 37 studies were included in the meta-analysis. There was a standardised mean difference (SMD) of − 0.54 (95% CI − 0.70, − 0.37, p = 0.00001) in favour of INT compared to SIT for glucose. With respect to insulin, there was an SMD of − 0.56 (95% CI − 0.74, − 0.38, p = 0.00001) in favour of INT. For TAG, there was an SMD of − 0.26 (95% CI − 0.44, − 0.09, p = 0.002) in favour of INT. Body mass index (BMI) was associated with glucose responses (β = − 0.05, 95% CI − 0.09, − 0.01, p = 0.01), and insulin (β = − 0.05, 95% CI − 0.10, − 0.006, p = 0.03), but not TAG (β = 0.02, 95% CI − 0.02, 0.06, p = 0.37). When energy expenditure was matched, there was an SMD of − 0.26 (95% CI − 0.50, − 0.02, p = 0.03) in favour of INT for glucose, but no statistically significant SMDs for insulin, i.e. 0.35 (95% CI − 0.37, 1.07, p = 0.35), or TAG i.e. 0.08 (95% CI − 0.22, 0.37, p = 0.62). It is worth noting that there was possible publication bias for TAG outcomes when PA breaks were compared with sitting. Conclusion: The use of PA breaks during sitting moderately attenuated post-prandial glucose, insulin, and TAG, with greater glycaemic attenuation in people with higher BMI. There was a statistically significant small advantage for PA breaks over continuous exercise for attenuating glucose measures when exercise protocols were energy matched, but no statistically significant differences for insulin and TAG
Anti-Inflammatory Effects of Lactobacillus Rahmnosus and Bifidobacterium Breve on Cigarette Smoke Activated Human Macrophages
Chronic obstructive pulmonary disease (COPD) is a major global health problem with cigarette smoke (CS) as the main risk factor for its development. Airway inflammation in COPD involves the increased expression of inflammatory mediators such as CXCL-8 and IL-1β which are important mediators for neutrophil recruitment. Macrophages are an important source of these mediators in COPD. Lactobacillus rhamnosus (L. rhamnosus) and Befidobacterium breve (B. breve) attenuate the development of 'allergic asthma' in animals but their effects in COPD are unknown.To determine the anti-inflammatory effects of L. rhamnosus and B. breve on CS and Toll-like receptor (TLR) activation.We stimulated the human macrophage cell line THP-1 with CS extract in the presence and absence of L. rhamnosus and B. breve and measured the expression and release of inflammatory mediators by RT-qPCR and ELISA respectively. An activity assay and Western blotting were used to examine NF-κB activation.Both L. rhamnosus and B. breve were efficiently phagocytized by human macrophages. L. rhamnosus and B. breve significantly suppressed the ability of CS to induce the expression of IL-1β, IL-6, IL-10, IL-23, TNFα, CXCL-8 and HMGB1 release (all p<0.05) in human THP-1 macrophages. Similar suppression of TLR4- and TLR9-induced CXCL8 expression was also observed (p<0.05). The effect of L. rhamnosus and B. breve on inflammatory mediator release was associated with the suppression of CS-induced NF-κB activation (p<0.05).This data indicate that these probiotics may be useful anti-inflammatory agents in CS-associated disease such as COPD
Влияние размера частиц горной породы на параметры пневмотранспортирования
Приведені результати досліджень впливу розміру часток гірської породи, що транспортується, на параметри пневмотранспортування. Отримані залежності для визначення швидкості пневмотранспортування та витрат стислого повітря від розміру часток матеріалу, що транспортується, з урахуванням параметрів пневмотранспортної системи.The brought results over of researches of influence of size of parts of mountain breed that is
transported, on the parameters of pneumatic portage. The got dependences are for determination of speed of pneumatic portage and charges of the compressed air from the size of parts of material that is transported, taking into account the parameters of the pneumatic portage system
Elevated VMP1 expression in acute myeloid leukemia amplifies autophagy and is protective against venetoclax-induced apoptosis
© 2019, The Author(s). Vacuole membrane protein (VMP1) is a putative autophagy protein, which together with Beclin-1 acts as a molecular switch in activating autophagy. In the present study the role of VMP1 was analysed in CD34+ cells of cord blood (CB) and primary acute myeloid leukemia (AML) cells and cell lines. An increased expression of VMP1 was observed in a subset of AML patients. Functional studies in normal CB CD34+ cells indicated that inhibiting VMP1 expression reduced autophagic-flux, coinciding with reduced expansion of hematopoietic stem and progenitor cells (HSPC), delayed differentiation, increased apoptosis and impaired in vivo engraftment. Comparable results were observed in leukemic cell lines and primary AML CD34+ cells. Ultrastructural analysis indicated that leukemic cells overexpressing VMP1 displayed a reduced number of mitochondrial structures, while the number of lysosomal degradation structures was increased. The overexpression of VMP1 did not affect cell proliferation and differentiation, but increased autophagic-flux and improved mitochondrial quality, which coincided with an increased threshold for venetoclax-induced loss of mitochondrial outer membrane permeabilization (MOMP) and apoptosis. In conclusion, our data indicate that in leukemic cells high VMP1 is involved with mitochondrial quality control
On the Interpretation of Gravitational Corrections to Gauge Couplings
Several recent papers discuss gravitational corrections to gauge couplings
that depend quadratically on the energy. In the framework of the
background-field approach, these correspond in general to adding to the
effective action terms quadratic in the field strength but with higher-order
space-time derivatives. We observe that such terms can be removed by
appropriate local field redefinitions, and do not contribute to physical
scattering-matrix elements. We illustrate this observation in the context of
open string theory, where the effective action includes, among other terms, the
well-known Born-Infeld form of non-linear electrodynamics. We conclude that the
quadratically energy-dependent gravitational corrections are \emph{not}
physical in the sense of contributing to the running of a physically-measurable
gauge coupling, or of unifying couplings as in string theory.Comment: 4 page
Conjugated Alpha-Alumina nanoparticle with vasoactive intestinal peptide as a Nano-drug in treatment of allergic asthma in mice
Asthma is a chronic respiratory disease characterized by airway inflammation, bronchoconstriction, airway hyperresponsiveness and recurring attacks of impaired breathing. Vasoactive intestinal peptide (VIP) has been proposed as a novel anti-asthma drug due to its effects on airway smooth muscle relaxation, bronchodilation and vasodilation along with its immunomodulatory and anti-inflammatory properties. In the current study, we investigated the therapeutic effects of VIP when conjugated with α-alumina nanoparticle (α-AN) to prevent enzymatic degradation of VIP in the respiratory tract. VIP was conjugated with α-AN. Balb/c mice were sensitized and challenges with ovalbumin (OVA) or PBS and were divided in four groups; VIP-treated, α-AN-treated, α-AN-VIP-treated and beclomethasone-treated as a positive control group. Specific and total IgE level, airway hyperresponsiveness (AHR), bronchial cytokine expression and lung histology were measured. α-AN-VIP significantly reduced the number of eosinophils (Eos), serum IgE level, Th2 cytokines and AHR. These effects of α-AN-VIP were more pronounced than that seen with beclomethasone or VIP alone (P<0.05). The current data indicate that α-AN-VIP can be considered as an effective nano-drug for the treatment of asthma
Возможности использования ксеноселезенки в клинической практике
Рассмотрена проблема применения ксеноселезенки в клинике. Показана целесообразность применения криобиологических технологий для получения биологически активных экстрактов из фрагментов ксеноселезенки. Разработан такой экстракт, определены его биофармацевтические свойства и клиническая эффективность при эндобронхиальном введении больным с абсцессами легких.The problem of xenospleen use in clinical practice is discussed. Reasonability of application of cryobiological technologies to obtain biologically active extracts from xenospleen fragments is shown. The extract has been developed, its biopharmaceutical properties and clinical efficacy at endobronchial administration in patients with lung abscess is shown
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