Effects of Chronic Electronic Vapor Exposure on Body Weight, Appetite, and Metabolism

Cigarette smokers weigh less than non-smokers and gain weight upon smoking cessation. Electronic cigarettes (E-cigs) have been used as a smoking cessation tool among many, however, their effects on metabolism, appetite, and energy balance are virtually unknown. This study compares the effects of chronic E-cig vapor exposure on body mass, food intake, metabolism, and body composition in mice. We hypothesized that E-cig exposure would elicit similar changes on body mass, body composition, food intake, and metabolic and appetite-regulating markers as conventional cigarettes (i.e. 3R4F reference cigarette). Female C57BL/6 mice were exposed to filtered room air (n=15), mainstream smoke from 3R4F reference cigarettes (n=15), or E-cig vapor (n=15) for a total of 8-months (4 h/d, 5d/wk). Body mass, food intake, metabolic and appetite-regulating markers, heat production, and body composition were measured. Weight gain, fat-free mass (FFM), and fat mass were significantly elevated in E-cig and control mice compared to 3R4F mice. Food consumption and heat production (kcal expended/hr) was significantly increased in E-cig mice compared to control and 3R4F mice. Appetite-regulating markers (NPY, POMC, leptin, and GLP-1) were similar between all groups. Mitochondrial uncouplers (UCP-1 and UCP-3) remained unchanged between E-cig and control groups, however, UCP-1 was significantly elevated in E-cig mice compared to 3R4F mice and UCP-3 was significantly elevated in control vs. 3R4F mice. Oxygen consumption (VO2) and carbon dioxide production (VCO2) were also significantly elevated in E-cig and 3R4F mice compared to control mice, while respiratory exchange ratios (RER) were unchanged. Unlike conventional cigarettes, we found that E-cig exposure did not elicit reductions in total body or adipose mass. This suggests the effects of E-cig may not be the same as that occurring with traditional tobacco cigarettes, or that the exposure to nicotine and/or other chemicals in the E-cig liquid elicits a different response on appetite or feeding behavior. While E-cig mice increased food intake, their basal metabolism was also elevated, suggesting energy dissipation resulting in a similar net energy balance compared to control mice. Further studies are needed to evaluate the effect that flavorings and/or the compounds produced in E-cig vapor exert on metabolism, energy balance, and the neural regulation of appetite

Bethe-Salpeter equation: 3D reductions, heavy mass limits and abnormal solutions

We show that the 3D reductions of the Bethe-Salpeter equation have the same bound state spectrum as the original equation, with the possible exception of some solutions for which the corresponding 3D wave function vanishes. The abnormal solutions of the Bethe-Salpeter equation (corresponding to excitations in the relative time-energy degree of freedom), when they exist, are recovered in the 3D reductions via a complicated dependence of the final potential on the total energy. We know however that the one-body (or one high mass) limit of some 3D reductions of the exact Bethe-Salpeter equation leads to a compact 3D equation (by a mutual cancellation of the ladder and crossed graph contributions), which does not exhibit this kind of dependence on the total energy anymore. We conclude that the exact Bethe-Salpeter equation has no abnormal solution at this limit, or has only solutions for which our 3D wave function vanishes. This is in contrast with the results of the ladder approximation, where no such cancellation occurs. We draw the same conclusions for the static model, which we obtain by letting the mass of the lighter particle go also to infinity. These results support Wick's conjecture that the abnormal solutions are a spurious consequence of the ladder approximation.Comment: 11 pages Latex, 1 figure Postscript. Submitted to Journal of Physics

A new method of quantization of classical solutions

Using stochastic quantization method we derive equations for correlators of quantum fluctuations around the classical solution in the massless phi^4 theory. The obtained equations are then solved in the lowest orders of perturbation theory, and the first correction to the free propagator of a quantum fluctuation is calculated.Comment: 8 page

How to study basement membrane stiffness as a biophysical trigger in prostate cancer and other age-related pathologies or metabolic diseases

Here we describe a protocol that can be used to study the biophysical microenvironment related to increased thickness and stiffness of the basement membrane (BM) during age-related pathologies and metabolic disorders (e.g. cancer, diabetes, microvascular disease, retinopathy, nephropathy and neuropathy). The premise of the model is non-enzymatic crosslinking of reconstituted BM (rBM) matrix by treatment with glycolaldehyde (GLA) to promote advanced glycation endproduct (AGE) generation via the Maillard reaction. Examples of laboratory techniques that can be used to confirm AGE generation, non-enzymatic crosslinking and increased stiffness in GLA treated rBM are outlined. These include preparation of native rBM (treated with phosphate-buffered saline, PBS) and stiff rBM (treated with GLA) for determination of: its AGE content by photometric analysis and immunofluorescent microscopy, its non-enzymatic crosslinking by ((sodium dodecyl sulfate polyacrylamide gel electrophoresis)) (SDS PAGE) as well as confocal microscopy, and its increased stiffness using rheometry. The procedure described here can be used to increase the rigidity (elastic moduli, E) of rBM up to 3.2-fold, consistent with measurements made in healthy versus diseased human prostate tissue. To recreate the biophysical microenvironment associated with the aging and diseased prostate gland three prostate cell types were introduced on to native rBM and stiff rBM: RWPE-1, prostate epithelial cells (PECs) derived from a normal prostate gland; BPH-1, PECs derived from a prostate gland affected by benign prostatic hyperplasia (BPH); and PC3, metastatic cells derived from a secondary bone tumor originating from prostate cancer. Multiple parameters can be measured, including the size, shape and invasive characteristics of the 3D glandular acini formed by RWPE-1 and BPH-1 on native versus stiff rBM, and average cell length, migratory velocity and persistence of cell movement of 3D spheroids formed by PC3 cells under the same conditions. Cell signaling pathways and the subcellular localization of proteins can also be assessed

Induced two-photon decay of the 2s level and the rate of cosmological hydrogen recombination

Induced emission due to the presence of soft CMB photons slightly increases the two-photon decay rate of the 2s level of hydrogen defining the rate of cosmological recombination. This correspondingly changes the degree of ionization, the visibility function and the resulting primordial temperature anisotropies and polarization of the CMB on the percent level. These changes exceed the precision of the widely used CMBFAST and CAMB codes by more than one order of magnitude and can be easily taken into account.Comment: 5 pages, 5 figure, accepted by Astronomy and Astrophysic

Ultrafast dynamics of coherences in the quantum Hall system

Using three-pulse four-wave-mixing optical spectroscopy, we study the ultrafast dynamics of the quantum Hall system. We observe striking differences as compared to an undoped system, where the 2D electron gas is absent. In particular, we observe a large off-resonant signal with strong oscillations. Using a microscopic theory, we show that these are due to many-particle coherences created by interactions between photoexcited carriers and collective excitations of the 2D electron gas. We extract quantitative information about the dephasing and interference of these coherences.Comment: 4 pages, 4 figures, to be published in Phys. Rev. Let

Salvaging Affymetrix probes after probe-level re-annotation

Background: Affymetrix GeneChips can be re-annotated at the probe-level by breaking up the original probe-sets and recomposing new probe-sets based on up-to-date genomic knowledge, such as available in Entrez Gene. This results in custom Chip Description Files (CDF). Using these custom CDFs improves the quality of the data and thus the results of related gene expression studies. However, 44-71% of the probes on a GeneChip are lost in this re-annotation process. Although generally aimed at less known genes, losing these probes obviously means a substantial loss of expensive experiment data. Biologists are therefore very reluctant to adopt this approach. Findings: We aimed to re-introduce the non-affected Affymetrix probe-sets after these re-annotation procedures. For this, we developed an algorithm (CDF-Merger) and applied it to standard Affymetrix CDFs and custom Brainarray CDFs to obtain Hybrid CDFs. Thus, salvaging lost Affymetrix probes with our CDF-Merger restored probe content up to 94%. Because the salvaged probes (up to 54% of the probe content on the arrays) represent less-reliable probe-sets, we made the origin of all probe-set definitions traceable, so biologists can choose at any time in their analyses, which subset of probe-sets they want to use. Conclusion: The availability of up-to-date Hybrid CDFs plus R environment allows for easy implementation of our approach

Finite element approximation of the p(⋅)p(\cdot)-Laplacian

We study a~priori estimates for the Dirichlet problem of the $p(\cdot)$-Laplacian, $$-\mathrm{div}(|\nabla v|^{p(\cdot)-2} \nabla v) = f.$$ We show that the gradients of the finite element approximation with zero boundary data converges with rate $O(h^\alpha)$ if the exponent $p$ is $\alpha$-H\"{o}lder continuous. The error of the gradients is measured in the so-called quasi-norm, i.e. we measure the $L^2$-error of $|\nabla v|^{\frac{p-2}{2}} \nabla v$