Asteroids' physical models from combined dense and sparse photometry and scaling of the YORP effect by the observed obliquity distribution

The larger number of models of asteroid shapes and their rotational states derived by the lightcurve inversion give us better insight into both the nature of individual objects and the whole asteroid population. With a larger statistical sample we can study the physical properties of asteroid populations, such as main-belt asteroids or individual asteroid families, in more detail. Shape models can also be used in combination with other types of observational data (IR, adaptive optics images, stellar occultations), e.g., to determine sizes and thermal properties. We use all available photometric data of asteroids to derive their physical models by the lightcurve inversion method and compare the observed pole latitude distributions of all asteroids with known convex shape models with the simulated pole latitude distributions. We used classical dense photometric lightcurves from several sources and sparse-in-time photometry from the U.S. Naval Observatory in Flagstaff, Catalina Sky Survey, and La Palma surveys (IAU codes 689, 703, 950) in the lightcurve inversion method to determine asteroid convex models and their rotational states. We also extended a simple dynamical model for the spin evolution of asteroids used in our previous paper. We present 119 new asteroid models derived from combined dense and sparse-in-time photometry. We discuss the reliability of asteroid shape models derived only from Catalina Sky Survey data (IAU code 703) and present 20 such models. By using different values for a scaling parameter cYORP (corresponds to the magnitude of the YORP momentum) in the dynamical model for the spin evolution and by comparing synthetics and observed pole-latitude distributions, we were able to constrain the typical values of the cYORP parameter as between 0.05 and 0.6.Comment: Accepted for publication in A&A, January 15, 201

Early Hypothalamic FTO Overexpression in Response to Maternal Obesity – Potential Contribution to Postweaning Hyperphagia

Intrauterine and postnatal overnutrition program hyperphagia, adiposity and glucose intolerance in offspring. Single-nucleotide polymorphisms (SNPs) of the fat mass and obesity associated (FTO) gene have been linked to increased risk of obesity. FTO is highly expressed in hypothalamic regions critical for energy balance and hyperphagic phenotypes were linked with FTO SNPs. As nutrition during fetal development can influence the expression of genes involved in metabolic function, we investigated the impact of maternal obesity on FTO.Female Sprague Dawley rats were exposed to chow or high fat diet (HFD) for 5 weeks before mating, throughout gestation and lactation. On postnatal day 1 (PND1), some litters were adjusted to 3 pups (vs. 12 control) to induce postnatal overnutrition. At PND20, rats were weaned onto chow or HFD for 15 weeks. FTO mRNA expression in the hypothalamus and liver, as well as hepatic markers of lipid metabolism were measured.At weaning, hypothalamic FTO mRNA expression was increased significantly in offspring of obese mothers and FTO was correlated with both visceral and epididymal fat mass (P<0.05); body weight approached significance (P = 0.07). Hepatic FTO and Fatty Acid Synthase mRNA expression were decreased by maternal obesity. At 18 weeks, FTO mRNA expression did not differ between groups; however body weight was significantly correlated with hypothalamic FTO. Postnatal HFD feeding significantly reduced hepatic Carnitine Palmitoyltransferase-1a but did not affect the expression of other hepatic markers investigated. FTO was not affected by chronic HFD feeding.Maternal obesity significantly impacted FTO expression in both hypothalamus and liver at weaning. Early overexpression of hypothalamic FTO correlated with increased adiposity and later food intake of siblings exposed to HFD suggesting upregulation of FTO may contribute to subsequent hyperphagia, in line with some human data. No effect of maternal obesity was observed on FTO in adulthood

Can We Modify the Intrauterine Environment to Halt the Intergenerational Cycle of Obesity?

Child obesity is a global epidemic whose development is rooted in complex and multi-factorial interactions. Once established, obesity is difficult to reverse and epidemiological, animal model, and experimental studies have provided strong evidence implicating the intrauterine environment in downstream obesity. This review focuses on the interplay between maternal obesity, gestational weight gain and lifestyle behaviours, which may act independently or in combination, to perpetuate the intergenerational cycle of obesity. The gestational period, is a crucial time of growth, development and physiological change in mother and child. This provides a window of opportunity for intervention via maternal nutrition and/or physical activity that may induce beneficial physiological alternations in the fetus that are mediated through favourable adaptations to in utero environmental stimuli. Evidence in the emerging field of epigenetics suggests that chronic, sub-clinical perturbations during pregnancy may affect fetal phenotype and long-term human data from ongoing randomized controlled trials will further aid in establishing the science behind ones predisposition to positive energy balance

Increased Cardiovascular Reactivity to Acute Stress and Salt-Loading in Adult Male Offspring of Fat Fed Non-Obese Rats

Diet-induced obesity in rat pregnancy has been shown previously to be associated with consistently raised blood pressure in the offspring, attributed to sympathetic over-activation, but the relative contributions to this phenotype of maternal obesity versus raised dietary fat is unknown. Sprague-Dawley female rats were fed either a control (4.3% fat, n = 11) or lard-enriched (23.6% fat, n = 16) chow 10 days prior to mating, throughout pregnancy and lactation. In conscious adult (9-month-old) offspring cardiovascular parameters were measured (radiotelemetry). The short period of fat-feeding did not increase maternal weight versus controls and the baseline blood pressure was similar in offspring of fat fed dams (OF) and controls (OC). However, adult male OF showed heightened cardiovascular reactivity to acute restraint stress (p<0.01; Δ systolic blood pressure (SBP) and Δheart rate (HR)) with a prolonged recovery time compared to male OC. α1/β-adrenergic receptor blockade normalised the response. Also, after dietary salt-loading (8%-NaCl ad libitum for 1 week) male OF demonstrated higher SBP (p<0.05) in the awake phase (night-time) and increased low/high frequency ratio of power spectral density of HR variability versus OC. Baroreflex gain and basal power spectral density components of the heart rate or blood pressure were similar in male OF and OC. Minor abnormalities were evident in female OF. Fat feeding in the absence of maternal obesity in pregnant rats leads to altered sympathetic control of cardiovascular function in adult male offspring, and hypertension in response to stressor stimuli

Experimental type II diabetes and related models of impaired glucose metabolism differentially regulate glucose transporters at the proximal tubule brush border membrane.

What is the central question of this study? Although SGLT2 inhibitors represent a promising treatment for patients suffering from diabetic nephropathy, the influence of metabolic disruption on the expression and function of glucose transporters is largely unknown. What is the main finding and its importance? In vivo models of metabolic disruption (Goto-Kakizaki type II diabetic rat and junk-food diet) demonstrate increased expression of SGLT1, SGLT2 and GLUT2 in the proximal tubule brush border. In the type II diabetic model, this is accompanied by increased SGLT- and GLUT-mediated glucose uptake. A fasted model of metabolic disruption (high-fat diet) demonstrated increased GLUT2 expression only. The differential alterations of glucose transporters in response to varying metabolic stress offer insight into the therapeutic value of inhibitors. SGLT2 inhibitors are now in clinical use to reduce hyperglycaemia in type II diabetes. However, renal glucose reabsorption across the brush border membrane (BBM) is not completely understood in diabetes. Increased consumption of a Western diet is strongly linked to type II diabetes. This study aimed to investigate the adaptations that occur in renal glucose transporters in response to experimental models of diet-induced insulin resistance. The study used Goto-Kakizaki type II diabetic rats and normal rats rendered insulin resistant using junk-food or high-fat diets. Levels of protein kinase C-βI (PKC-βI), GLUT2, SGLT1 and SGLT2 were determined by Western blotting of purified renal BBM. GLUT- and SGLT-mediated d-[(3) H]glucose uptake by BBM vesicles was measured in the presence and absence of the SGLT inhibitor phlorizin. GLUT- and SGLT-mediated glucose transport was elevated in type II diabetic rats, accompanied by increased expression of GLUT2, its upstream regulator PKC-βI and SGLT1 protein. Junk-food and high-fat diet feeding also caused higher membrane expression of GLUT2 and its upstream regulator PKC-βI. However, the junk-food diet also increased SGLT1 and SGLT2 levels at the proximal tubule BBM. Glucose reabsorption across the proximal tubule BBM, via GLUT2, SGLT1 and SGLT2, is not solely dependent on glycaemic status, but is also influenced by diet-induced changes in glucose metabolism. We conclude that different metabolic disturbances result in complex adaptations in renal glucose transporter protein levels and function

The inhibitive effect of hexamethylenetetramine on the acid corrosion of steel

The efficiency of hexamethylenetetramine (HMTA), as corrosion inhibitors for steel in de-aerated 0.3 M HCl, 0.1 M H2SO4 and 0.1 M H2SO4 + 1.0 × 10-3 M HCl solutions have been determined by electrochemical studies. It was found that the HMTA acts a good corrosion inhibitor for steel corrosion in acids solutions. Increase in inhibition efficiency with the increase of concentrations of HMTA shows that inhibition actions are due to adsorption on the steel surface and adsorption follows the Langmuir isotherm. From the adsorption isotherms values of equilibrium constant (Kads), values of free energies of adsorption (? Gads °), were calculated. The effect of temperature on the corrosion behaviour in the presence of 1.0 × 10-1 M inhibitors was studied in the temperature range of 293-323 K. The inhibition efficiency of HMTA increased with increasing temperature up to 323 K. Activation energies (Ea*) were calculated from the obtained corrosion rates at different temperatures. Results obtained from both potentiodynamic polarisation and AC impedance measurements reveal that the compound is an effective inhibitor for the corrosion of steel and behave better in HCl than in H2SO4. Surface analyses were also carried out to establish the mechanism of corrosion inhibition of steel in acidic media. © 2007 Elsevier B.V. All rights reserved

Corrosion inhibition potentials of 4-(4-bromophenyl) thiosemicarbazide for mild steel in 1.0 M HCl as theoretical and experimental

This examination researched the impact of changing measures of 4-(4-bromophenyl) Thiosemicarbazide (4-BrPhTSC) by assessing air conditioning impedance and AC and flow potentiometry in a 1 M HCl arrangement at 20°C. In an unlimited arrangement, when the E corr value is - 0.518 V, the concentration of the inhibitor solution changes and the grouping of the inhibitor changes. The present's thickness of the anodic and cathodic districts is bring down contrasted with that of the 1.0 M HCl arrangement, with an I corr estimation of 158.78 µA.cm -2 in the uninhibited arrangement and 8.10 µA.cm -2 at the 1x10 -2 M concentration of 4-BrPhTSC. It very well may be seen that as the grouping of the inhibitor builds, the consumption current thickness value diminishes, and the restraint productivity value likewise increments. The percent restraint proficiency extended from 71% to 95%. For the uninhibited and most astounding grouping of 4-BrPhTSC arrangement, the estimations of Rp blank and Rp inh were 235 and 2006 ?cm-2, separately, CPE blank and CPE inh were 348 and 36 µF.cm -2 , individually, n blank and n inh were 0.94 and 0.84. As the Rp esteem builds, the CPE esteem and n diminish as the inhibitor focus increments, potentially because of abatement in neighborhood dielectric steady or an expanded thickness at the metal/arrangement interface. The adsorption of the inhibitor on the surface of the low carbon steel fits in with the Langmuir show. Also, the adsorption harmony steady and the adsorption free vitality were evaluated. For the subsidiaries of 4-BrPhTSC, the estimation of ?Go ads and is - 36.00 kJ mol -1 , demonstrating that the adsorption of these inhibitors includes two sorts of communications: physical adsorption and chemisorption. The thickness utilitarian hypothesis (DFT) of the B3LYP work with the 6-311G (d,p) premise set was performed on 4-BrPhTSC as appeared in Table 1, Table 2. © 2019 The Authors

MEASURING TERRESTRIAL RADIO FREQUENCY INTERFERENCE AT ORBIT ALTITUDES

International Telemetering Conference Proceedings / October 09-11, 1973 / Sheraton Inn Northeast, Washington, D.C.Satellite systems, by virtue of their large terrestrial fields of view, may be exposed to a great many man-made radio signals the aggregate effects of which can be deleterious to satellite receivers. An experiment has been designed to measure and characterize such man-made interference at orbital altitudes. The experiment, as designed, requires dedicated hardware on a spacecraft of specified orbit and will measure (within the frequency range of 400 MHz to 12.4 GHz) peak levels of interference in cells dimensioned in space, time, and frequency. The experiment will provide data indicative of some of the statistical characteristics of interference levels at satellite orbital altitudes and will provide designers of satellite communications links with new facilities for the prediction and prevention of interference problems, and should provide a considerable data base for use in long range planning of spectrum utilization.International Foundation for TelemeteringProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit http://www.telemetry.org/index.php/contact-us if you have questions about items in this collection

The inhibitive effect of hexamethylenetetramine on the acid corrosion of steel

WOS: 000247862200013The efficiency of hexamethylenetetramine (HMTA), as corrosion inhibitors for steel in de-aerated 0.3M HCl, 0.1M H2SO4 and 0.1M H2SO4 + 1.0 x 10(-3) M HCl solutions have been determined by electrochemical studies. It was found that the HMTA acts a good corrosion inhibitor for steel corrosion in acids solutions. Increase in inhibition efficiency with the increase of concentrations of HMTA shows that inhibition actions are due to adsorption on the steel surface and adsorption follows the Langmuir isotherm. From the adsorption isotherms values of equilibrium constant (K-ads) values of free energies of adsorption (Delta G(ads)degrees), were calculated. The effect of temperature on the corrosion behaviour in the presence of 1.0 x 10(-1) M inhibitors was studied in the temperature range of 293-323 K. The inhibition efficiency of HMTA increased with increasing temperature up to 323 K. Activation energies (E-a*) were calculated from the obtained corrosion rates at different temperatures. Results obtained from both potentiodynamic polarisation and AC impedance measurements reveal that the compound is an effective inhibitor for the corrosion of steel and behave better in HCl than in H2SO4. Surface analyses were also carried out to establish the mechanism of corrosion inhibition of steel in acidic media. (c) 2007 Elsevier B.V. All rights reserved