Quasienergy Spectra Of Quantum Dynamical Systems

We present a technique that yields in analytic fashion the quasienergy spectrum of bounded quantum systems in the presence of time-periodic perturbations. It also allows for the calculation of statistical averages using simple algebraic manipulations and provides tractable solutions even for systems with a large number of levels. We also report on numerical calculations for systems with few number of levels in and out of resonance, and which show the recurrences predicted by the Hogg-Huberman theorem [Phys. Rev. Lett. 48, 711 (1982); Phys. Rev. A 28, 22 (1983)]. © 1984 The American Physical Society.30417521759CONACYT; Nederlandse Organisatie voor Wetenschappelijk Onderzoek; Nederlandse Organisatie voor Wetenschappelijk Onderzoek; NCN; Nederlandse Organisatie voor Wetenschappelijk Onderzoek; NRF; Nederlandse Organisatie voor Wetenschappelijk Onderzoek; NSFC; Nederlandse Organisatie voor Wetenschappelijk Onderzoek; Nederlandse Organisatie voor Wetenschappelijk Onderzoek; DNRF; Nederlandse Organisatie voor Wetenschappelijk Onderzoek; ERC; Nederlandse Organisatie voor Wetenschappelijk Onderzoek; Nederlandse Organisatie voor Wetenschappelijk Onderzoek; INFN; Nederlandse Organisatie voor Wetenschappelijk Onderzoek; NKTH; Nederlandse Organisatie voor Wetenschappelijk Onderzoek; NWO; Nederlandse Organisatie voor Wetenschappelijk Onderzoek; OTKA; Nederlandse Organisatie voor Wetenschappelijk Onderzoek; RAS; Nederlandse Organisatie voor Wetenschappelijk Onderzoek; RFBR; Nederlandse Organisatie voor Wetenschappelijk Onderzoek;  Nederlandse Organisatie voor Wetenschappelijk Onderzoek; STFC; Nederlandse Organisatie voor Wetenschappelijk Onderzoe

INDEPENDENT HYPOTHALAMIC CIRCUITS FOR SOCIAL AND PREDATOR FEAR

Fear is a distressing negative sensation induced by a perceived threat. This emotion is necessary for the survival of the individual, since it guarantees appropriate responses to life challenging threats. In the last decades research on the neural mechanisms underling such emotion both in humans and in animal models have been mostly focused on the amygdala. In particular fear models in rodents typically rely on foot shock based paradigms. However, innate and learned fear elicited by other stimuli such as predators or aggressive members of the same species has been shown to be regulated by other circuits where the triggering, coordination and the expression of fear seem to be centered in the hypothalamus and periaqueductal grey. Nevertheless very little is known about the function and physiology of these structures in fear processing. To study the function of the medial hypothalamic fear circuit, we developed a novel behavioral paradigm to measure innate and conditioned fear responses to social and predator threats in mice. We subsequently created tools to selectively inhibit specific hypothalamic nuclei during the fear and we observed the inhibition of the ventromedial hypothalamus, a nucleus previously studied for its function in feeding, sex and aggression, specifically impaired social and predator fear but not foot shock fear. Moreover we demonstrated that different portions of this nucleus account for fear to different threats with the dorsomedial portion, previously implicated in feeding function, processing predator fear, and the ventrolateral portion, previously implicated in sex and aggression, processing social fear. Our results demonstrate that the hypothalamus plays a crucial role in fear processing even if it is not recruited during foot shock exposure, suggesting that it might be a good target for the treatment of fear related disorders like panic or phobias and we are now trying to identify possible drugs specifically acting in this area. On the other hand, we showed that specific hypothalamic subnuclei are recruited selectively during social or predator fear, corroborating the hypothesis that different types of fear are processed by separate brain circuits. Such evidence opens the possibility of targeted therapy of pathological fear in humans. Interestingly these same hypothalamic structures are fundamental regulators of non-fear motivated behaviors that are essential for survival such as feeding behavior, aggression and sex and we are now investigating how the same nuclei can orchestrate multiple functions

Spironolactone treatment attenuates vascular dysfunction in type 2 diabetic mice by decreasing oxidative stress and restoring NO/GC signaling

Type 2 diabetes (DM2) increases the risk of cardiovascular disease. Aldosterone, which has pro-oxidative and pro-inflammatory effects in the cardiovascular system, is positively regulated in DM2. We assessed whether blockade of mineralocorticoid receptors (MR) with spironolactone decreases reactive oxygen species (ROS)-associated vascular dysfunction and improves vascular nitric oxide (NO) signaling in diabetes. Leptin receptor knockout [LepRdb/LepRdb (db/db)] mice, a model of DM2, and their counterpart controls [LepRdb/LepR+, (db/+) mice] received spironolactone (50 mg/kg body weight/day) or vehicle (ethanol 1%) via oral per gavage for 6 weeks. Spironolactone treatment abolished endothelial dysfunction and increased endothelial nitric oxide synthase (eNOS) phosphorylation (Ser1177) in arteries from db/db mice, determined by acetylcholine-induced relaxation and Western Blot analysis, respectively. MR antagonist therapy also abrogated augmented ROS-generation in aorta from diabetic mice, determined by lucigenin luminescence assay. Spironolactone treatment increased superoxide dismutase-1 and catalase expression, improved sodium nitroprusside and BAY 41-2272-induced relaxation, and increased soluble guanylyl cyclase (sGC) β subunit expression in arteries from db/db mice. Our results demonstrate that spironolactone decreases diabetes-associated vascular oxidative stress and prevents vascular dysfunction through processes involving increased expression of antioxidant enzymes and sGC. These findings further elucidate redox-sensitive mechanisms whereby spironolactone protects against vascular injury in diabetes

Silver Sulphadiazine- xanthan gum- hyaluronic Acid Composite Hydrogel for Wound Healing: Formulation Development and in vivo Evaluation

Background: Development and modifications of hybrid hydrogels have been done to improve biological properties or to decrease the disadvantages of biomaterials.Objectives: The efficacy of hyaluronic acid in combination with silver sulphadiazine in wound healing was investigated. The retaining properties of xanthan gum to aid re- epithelialization was also explored.Materials and Method: Four hybrid hydrogels comprising of different concentrations of xanthan gum, eugenol and antimicrobial agents – hyaluronic acid and silver sulphadiazine were formulated. The physicochemical properties of the gels were assessed, and the antimicrobial effectiveness of the different hydrogel were determined using the extent of wound closure as an index.Results: The hydrogel samples had approximately 90% moisture content with rate of evaporation between 26- 32% for a 5 h period at 37oC. The pH of all formulations was between 7.59 - 8.05 considering that the formulation would be applied to underlying tissues of the skin. The swelling index after a 12 h period in distilled water was 10% for HX 1, 27% for HX 2, 29% for HX 3 and 30% for HX 4. There was no new peak observed in the FTIR analysis to indicate formation of new bonds.Conclusion: Incorporation of silver sulphadiazine at 0.1% and hyaluronic acid at 1.5% in the formulation yielded the best results with regards to least presence of inflammatory cell infiltrates and excellent wound closure at 14 days compared to the control and other formulations. Further investigation may be required for clinical use as an effective wound dressing material. Keywords: Silver sulphadiazine, Xanthan gum, Hyaluronic acid, Hydrogels, Wound healing

Antibrowning and antimicrobial effects of onion essential oil to preserve the quality of cut potatoes

This study evaluated the effect of onion essential oil (OEO) (0, 0.5, 2.5, and 5 mg ml−1) on microbial growth, browning decay, and sensorial appealing of cut potatoes stored for 15 days at 4 °C. Dipropyl disulphide and dipropyl trisulphide were the main constituents identified in OEO, and its application at a dose of 0.5 mg mlt-1 was the most effective to prevent browning (38.5% inhibition respect to control) during storage, inhibiting PPO activity (39% respect to control) after the treatment. The higher the added OEO concentration the lower microbial growth of the treated product was, achieving a reduction of 1.27 log CFU g−1 for the 5 mg ml−1 treatment. The odour and flavour appealing of cut potatoes were well received by the panelists after 10 days of storage. Therefore, the use of OEO in cut potatoes has a potential as antimicrobial and antibrowning agent

Análise geoambiental do riacho Santa Bárbara Zona urbana – Parnarama-Maranhão

Análise geoambiental do riacho Santa BárbaraZona urbana – Parnarama-Maranhã

Experimental study of negative photoconductivity in n-PbTe(Ga) epitaxial films

We report on low-temperature photoconductivity (PC) in n-PbTe(Ga) epitaxial films prepared by the hot-wall technique on -BaF_2 substrates. Variation of the substrate temperature allowed us to change the resistivity of the films from 10^8 down to 10_{-2} Ohm x cm at 4.2 K. The resistivity reduction is associated with a slight excess of Ga concentration, disturbing the Fermi level pinning within the energy gap of n-PbTe(Ga). PC has been measured under continuous and pulse illumination in the temperature range 4.2-300 K. For films of low resistivity, the photoresponse is composed of negative and positive parts. Recombination processes for both effects are characterized by nonexponential kinetics depending on the illumination pulse duration and intensity. Analysis of the PC transient proves that the negative photoconductivity cannot be explained in terms of nonequilibrium charge carriers spatial separation of due to band modulation. Experimental results are interpreted assuming the mixed valence of Ga in lead telluride and the formation of centers with a negative correlation energy. Specifics of the PC process is determined by the energy levels attributed to donor Ga III, acceptor Ga I, and neutral Ga II states with respect to the crystal surrounding. The energy level corresponding to the metastable state Ga II is supposed to occur above the conduction band bottom, providing fast recombination rates for the negative PC. The superposition of negative and positive PC is considered to be dependent on the ratio of the densities of states corresponding to the donor and acceptor impurity centers.Comment: 7 pages, 4 figure

Monte Carlo Comparisons to a Cryogenic Dark Matter Search Detector with low Transition-Edge-Sensor Transition Temperature

We present results on phonon quasidiffusion and Transition Edge Sensor (TES) studies in a large, 3 inch diameter, 1 inch thick [100] high purity germanium crystal, cooled to 50 mK in the vacuum of a dilution refrigerator, and exposed with 59.5 keV gamma-rays from an Am-241 calibration source. We compare calibration data with results from a Monte Carlo which includes phonon quasidiffusion and the generation of phonons created by charge carriers as they are drifted across the detector by ionization readout channels. The phonon energy is then parsed into TES based phonon readout channels and input into a TES simulator

Heritabilities, proportions of heritabilities explained by GWAS findings, and implications of cross-phenotype effects on PR interval

Electrocardiogram (ECG) measurements are a powerful tool for evaluating cardiac function and are widely used for the diagnosis and prediction of a variety of conditions, including myocardial infarction, cardiac arrhythmias, and sudden cardiac death. Recently, genome-wide association studies (GWASs) identified a large number of genes related to ECG parameter variability, specifically for the QT, QRS, and PR intervals. The aims of this study were to establish the heritability of ECG traits, including indices of left ventricular hypertrophy, and to directly assess the proportion of those heritabilities explained by GWAS variants. These analyses were conducted in a large, Dutch family-based cohort study, the Erasmus Rucphen Family study using variance component methods implemented in the SOLAR (Sequential Oligogenic Linkage Analysis Routines) software package. Heritability estimates ranged from 34 % for QRS and Cornell voltage product to 49 % for 12-lead sum. Trait-specific GWAS findings for each trait explained a fraction of their heritability (17 % for QRS, 4 % for QT, 2 % for PR, 3 % for Sokolow–Lyon index, and 4 % for 12-lead sum). The inclusion of all ECG-associated single nucleotide polymorphisms explained an additional 6 % of the heritability of PR. In conclusion, this study shows that, although GWAS explain a portion of ECG trait variability, a large amount of heritability remains to be explained. In addition, larger GWAS for PR are likely to detect loci already identified, particularly those observed for QRS and 12-lead sum