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This study reports the effects of a high-fat (HF) diet on the iron (Fe) status of growing rats over 8 weeks. Tissue Fe levels were analysed by atomic absorption spectrophotometry, and whole-body adiposity was measured by dual-energy X-ray absorptiometry. Histopathology and morphometry of adipose tissue were performed. Liver homogenates were used for measuring ferroportin (Fpn)-1 protein levels by immunoblotting, and transcript levels were used for Fe genes measured by real-time PCR. Tissue Fe pools were fit to a compartmental biokinetic model in which Fe was assessed using 14 compartments and 27 transfer constants (kj,i from tissue “i” to tissue “j”) adapted from the International Commission on Radiological Protection (ICRP) 69. Ten kj,i were calculated from the experimental data using nonlinear regression, and 17 were estimated by allometry according to the formula kj,i = a · Mb. Validation of the model was carried out by comparing predicted and analysed Fe pool sizes in red blood cells (RBCs), the liver and the spleen. Body adiposity was negatively associated with serum Fe levels and positively associated with liver Fe stores. An inferred increase in Fe transfer from bone marrow to the liver paralleled higher hepatic Fe concentrations and ferritin heavy-chain mRNA levels in the HF diet-fed animals, suggesting that liver Fe accumulation occurred at least in part due to a favoured liver RBC uptake. If this feeding condition were to be prolonged, impaired Fe decompartmentalization may occur, ultimately resulting in dysmetabolic Fe overload.
While more and more long-period giant planets are discovered by direct imaging, the distribution of planets at these separations (≳5 AU) has remained largely uncertain, especially compared to planets in the inner regions of solar systems probed by RV and transit techniques. The low frequency, the detection challenges, and heterogeneous samples make determining the mass and orbit distributions of directly imaged planets at the end of a survey difficult. By utilizing Monte Carlo methods that incorporate the age, distance, and spectral type of each target, we can use all stars in the survey, not just those with detected planets, to learn about the underlying population. We have produced upper limits and direct measurements of the frequency of these planets with the most recent generation of direct imaging surveys. The Gemini NICI Planet-Finding Campaign observed 220 young, nearby stars at a median H-band contrast of 14.5 magnitudes at 1”, representing the largest, deepest search for exoplanets by the completion of the survey. The Gemini Planet Imager Exoplanet Survey is in the process of surveying 600 stars, pushing these contrasts to a few tenths of an arcsecond from the star. With the advent of large surveys (many hundreds of stars) using advanced planet-imagers we gain the ability to move beyond measuring the frequency of wide-separation giant planets and to simultaneously determine the distribution as a function of planet mass, semi-major axis, and stellar mass, and so directly test models of planet formation and evolution.
Epigenetic studies suggest that diseases that develop in adulthood are related to certain conditions to which the individual is exposed during the initial stages of life. Experimental evidence has demonstrated that offspring born to mothers maintained on high-Na diets during pregnancy have higher mean arterial pressure (MAP) in adulthood. Although these studies have demonstrated the importance of prenatal phases to hypertension development, no evidence regarding the role of high Na intake during postnatal phases in the development of this pathology has been reported. Therefore, in the present study, the effects of Na overload during childhood on induced water and Na intakes and on cardiovascular parameters in adulthood were evaluated. Experiments were carried out in two groups of 21-d-old rats: experimental group, maintained on hypertonic saline (0·3 m-NaCl) solution and food for 60 d, and control group, maintained on tap water and food. Later, both groups were given water and food for 15 d (recovery period). After the recovery period, chronic cannulation of the right femoral artery was performed in unanaesthetised rats to record baseline MAP and heart rate (HR). The experimental group was found to have increased basal MAP (98·6 (sem 2·6) v. 118·3 (sem 2·7) mmHg, P< 0·05) and HR (365·4 (sem 12·2) v. 398·2 (sem 7·5) beats per min, P< 0·05). There was a decrease in the baroreflex index in the experimental group when compared with that in the control group. A water and Na intake test was performed using furosemide. Na depletion was found to induce an increase in Na intake in both the control and experimental groups (12·1 (sem 0·6) ml and 7·8 (sem 1·1), respectively, P< 0·05); however, this increase was of lower magnitude in the experimental group. These results demonstrate that postnatal Na overload alters behavioural and cardiovascular regulation in adulthood.
Oxidative stress and neurotrophic factors have been implicated in the pathophysiology of bipolar disorder. Our objective was to determine whether plasma glutathione or brain-derived neurotrophic factor (BDNF) levels were abnormal in bipolar disorder and therefore useful as possible biomarkers.
Blood samples were collected from subsyndromal, medicated bipolar I patients (n = 50), recruited from OXTEXT, University of Oxford, and from 50 matched healthy controls. Total and oxidized glutathione levels were measured using an enzymatic recycling method and used to calculate reduced, percentage oxidized, ratio of reduced:oxidized and redox state. BDNF was measured using an enzyme-linked immunoassay. Self-monitored mood scores for the bipolar group were available (Quick Inventory of Depressive Symptomatology and the Altman Self-Rating Mania Scale) over an 8-week period.
Compared with controls, bipolar patients had significantly lower levels of total glutathione and it was more oxidized. BDNF levels were not different. Age of illness onset but not current mood state correlated with total glutathione levels and its oxidation status, so that lower levels of total and reduced glutathione were associated with later onset of disease, not length of illness.
Plasma glutathione levels and redox state detect oxidative stress even in subsyndromal patients with normal BDNF. It may relate to the onset and development of bipolar disorder. Plasma glutathione appears to be a suitable biomarker for detecting underlying oxidative stress and for evaluating the efficacy of antioxidant intervention studies.
Tritrichomonas foetus is a protist that causes bovine trichomoniasis and presents a well-developed Golgi. There are very few studies concerning the Golgi in trichomonads. In this work, monoclonal antibodies were raised against Golgi of T. foetus and used as a tool on morphologic and biochemical studies of this organelle. Among the antibodies produced, one was named mAb anti-Golgi 20.3, which recognized specifically the Golgi complex by fluorescence and electron microscopy. By immunoblotting this antibody recognized two proteins with 60 and 66 kDa that were identified as putative beta-tubulin and adenosine triphosphatase, respectively. The mAb 20.3 also recognized the Golgi complex of the Trichomonas vaginalis, a human parasite. In addition, the nucleotide coding sequences of these proteins were identified and included in the T. foetus database, and the 3D structure of the proteins was predicted. In conclusion, this study indicated: (1) adenosine triphosphatase is present in the Golgi, (2) ATPase is conserved between T. foetus and T. vaginalis, (3) there is new information concerning the nucleic acid sequences and protein structures of adenosine triphosphatase and beta-tubulin from T. foetus and (4) the mAb anti-Golgi 20.3 is a good Golgi marker and can be used in future studies.
High-redshift quasars are unique probes of the evolution of supermassive black holes and the intergalactic medium at the end of the epoch of reionization. We present the optical spectra of eight new z ~ 6 quasars selected from the Panoramic Survey Telescope & Rapid Response System 1 (Pan-STARRS1). Details of the selection strategy can be found in Bañados et al. (2014). With this work we increase the number of known quasars at z < 5.7 by more than 10%. The quasars discovered here span a large range of luminosities (19.6 ≤ zP1 ≤ 21.2) and are remarkably heterogeneous in their spectral features: half of them show bright emission lines whereas the other half show weak or no Lyα emission line. We find a larger fraction of weak–line emission quasars than in lower redshift studies, although still based on low number statistics, this may imply that the quasar population could be more diverse than previously thought.
We present preliminary results from two parallel programs to search for new substellar companions to nearby, young M-stars and to characterize the atmospheres of known planetary mass and temperature substellar companions. For the M-star survey, we are analyzing high angular resolution archival data on systems within 15pc, complementing a subset with well-determined young ages based on measurements of several age indicators. The results include stellar and substellar companion candidates, which we are currently pursuing with follow-up second epoch images. The characterization component of the project involves using LBT LMIRCam and MMT ARIES direct imaging and spectroscopy data to investigate the atmospheres of known young substellar companions with masses overlapping the planetary regime. These atmospheric studies will represent an analogous comparison to the atmospheres of young imaged planets, and provide a means to fundamentally test evolutionary models, enhancing our understanding of the overall substellar population.
To investigate the atmospheres of ultracool brown dwarfs with temperatures covering the range of transiting and directly imaged planets, we have monitored a sample of 76 L, T and Y brown dwarfs for infrared photometric variability. This survey was conducted in the J-band using both the SOFI camera on the 3.5-m NTT and the SWIRC camera on the 6.5-m MMT. Each target was observed for a period ranging from 2.0 hours to 6.0 hours, covering a significant fraction of the expected rotation period. Breakup of the iron and silicate clouds into a patchy cloud layer has been suggested as an explanation for the variability of several objects identified at the L/T transition, and a similar process with sulfide clouds may be manifest in T/Y transition objects; our data provides the first test of these patchy cloud scenarios across the entire brown dwarf spectral range.
We present the preliminary findings of an investigation of the multiplicity of debris disk stars identified within our Volume-limited A-star (VAST) multiplicity survey. Previous studies have produced conflicting results regarding the multiplicity fraction of debris disk-hosting stars compared with non-excess stars. By combining our large-scale volume-limited AO survey of A-type stars with the all-sky WISE catalogue, we have investigated the frequency of binary companions to a large sample of A-type stars with and without measured 22μm excess. The results of this study will allow for a greater understanding of the interaction between a companion star and a circumstellar debris disk, informing future study into the formation and stability of planetary-mass companions within binary systems.
In most studies on beef cattle longevity, only the cows reaching a given number of calvings by a specific age are considered in the analyses. With the aim of evaluating all cows with productive life in herds, taking into consideration the different forms of management on each farm, it was proposed to measure cow longevity from age at last calving (ALC), that is, the most recent calving registered in the files. The objective was to characterize this trait in order to study the longevity of Nellore cattle, using the Kaplan–Meier estimators and the Cox model. The covariables and class effects considered in the models were age at first calving (AFC), year and season of birth of the cow and farm. The variable studied (ALC) was classified as presenting complete information (uncensored = 1) or incomplete information (censored = 0), using the criterion of the difference between the date of each cow's last calving and the date of the latest calving at each farm. If this difference was >36 months, the cow was considered to have failed. If not, this cow was censored, thus indicating that future calving remained possible for this cow. The records of 11 791 animals from 22 farms within the Nellore Breed Genetic Improvement Program (‘Nellore Brazil’) were used. In the estimation process using the Kaplan–Meier model, the variable of AFC was classified into three age groups. In individual analyses, the log-rank test and the Wilcoxon test in the Kaplan–Meier model showed that all covariables and class effects had significant effects (P < 0.05) on ALC. In the analysis considering all covariables and class effects, using the Wald test in the Cox model, only the season of birth of the cow was not significant for ALC (P > 0.05). This analysis indicated that each month added to AFC diminished the risk of the cow's failure in the herd by 2%. Nonetheless, this does not imply that animals with younger AFC had less profitability. Cows with greater numbers of calvings were more precocious than those with fewer calvings.
This paper presents the results of the bulk laser damage performance of undoped epoxy thermosets with glassy and rubbery mechanical properties and two commercial polymethylmethacrylate (PMMA) samples. We demonstrate how thermomechanical properties such as glass transition temperature (Tg) and equilibrium shear modulus (Ge) affect laser damage threshold. The rubbery epoxy elastomer shows a damage threshold fluence one order of magnitude higher than PMMA and 2.5 orders of magnitude higher than a glassy epoxy thermoset. A solid-state guest-host limiter is made by doping the epoxy elastomer with zinc octabromotetraphenylporphyrin (ZnOBP). The limiting performance of the elastomer limiter is compared to a solution of ZnOBP and C60 in toluene. Photochemical hysteresis effects in the solid
limiter were also investigated.
To estimate dietary habits and other factors associated with inadequate blood pressure (BP) control in hypertensive patients adherent to antihypertensive drug treatment assisted by a Brazilian Family Doctor Program (FDP).
A cross-sectional study.
FDP units, Niterói, Rio de Janeiro, Brazil.
We included data from both male and female participants aged ≥20 years. Participants completed a standardized questionnaire containing questions related to demographics, socio-economic factors, comorbidities and lifestyle, as well as a validated FFQ and eleven additional qualitative questions to investigate dietary habits. Food items were divided into sixteen groups. Medical consultations were performed, BP measurements were taken, blood and urine samples were assessed and anthropometric and nutritional status was evaluated.
Individuals with inadequate BP control presented higher BMI values (prevalence ratio (PR) = 1·027, 95 % CI 1·009, 1·045) and also consumed more meat (PR = 1·091, 95 % CI 1·022, 1·165), which are potentially modifiable variables. Higher levels of serum creatinine (PR = 1·894, 95 % CI 1·241, 2·892) were also associated with inadequate BP control, as were skin colour (white). After inclusion of the Na excretion index, which is an indirect measure of salt intake, a slight decrease was observed in the PR for meat, which resulted in loss of statistical significance.
The results indicate that salt consumption, skin colour, BMI and serum creatinine are associated with inadequate BP control.
In this work we investigate the density of states at amorphous-crystalline silicon interface that play the key role in the heterostructure solar cell application. In particular we analyzed the defect density arising from plasma treatment of the crystalline surface. This process is useful to clean the crystalline surface, but greatly influenced the electrical properties of the device. We used low temperature (20K-300K) capacitance measurement performed in a wide range of frequency of signal probe (1Hz-10kHz). Differences in the capacitance profile between samples with various plasma dry treatments indicate different defect density profile at interface. With the aid of a finite difference model of the capacitance as a function of temperature and frequency we extract information from the measurements about the defect energy distribution at interface. As a result, the density and the nature of defects at interface will be correlated to the technological parameters as: wafer cleaning procedure, hydrogen plasma treatment, type and concentration of dopants at interface.
In this work we study the possibility to use amorphous silicon nitride, grown by plasma, as an alternative way to realize buffer layer in a-Si:H/c-Si heterostructure. We experimented several growing condition for silicon nitride depending on deposition parameters, obtaining samples highly transparent and with optical gap varying in the range 2.4 – 5.2 eV. We found evidence that the gap of the material is principally due to the NH3/N2 ratio. The very low absorption obtainable on this material was successfully utilized to increase the short circuit current density of the device respect to the standard cell with intrinsic amorphous silicon buffer, particularly in the low wavelength region as confirmed by quantum yield measurements. We optimized the thickness of the SiNx buffer layer respect to the photovoltaic parameters of the solar cell. A 0.5 nm thick SiNx ensures good photogeneration in blue region of the visible spectrum and does not appreciably degrade the transport mechanism of the heterojunction.
We describe a reversible technique for locally modifying the oxygen stoichiometry and electrical transport properties of superconducting thin films. A focused argon ion laser beam is scanned across the surface of a YBa2Cu3O7-x thinfilm, contained in a vacuum, at incident power levels well below those necessary for ablation. The change in oxygen stoichiometry is monitored in-situ by the room temperature electrical resistance. We have measured the superconducting properties of these locally modified films. The resulting R vs T curve for the composite structure (film/laserstripe/film) shows the expected double transition. The first transition, corresponding to the unmodified film, occurs at 87 K while the second transition, corresponding to the modified stripe, occurs at a lower temperature and is a function of the laser induced change in the room temperature electrical resistance. The critical current for the composite structure is depressed from the original film. The laser writing can be erasedor bleached out by room temperature exposure to an oxygen plasma.
The development of a hybrid heterojunction fabricated by growing ultrathin amorphous silicon by Plasma Enhanced Chemical Vapor Deposition using temperatures below 250°C offers the potential of obtaining high efficiency solar cells deposited on glassy substrates. The surface preparation represents one of the most critical steps. The first aim of etching is to remove the native oxide layer from the surface of the crystalline wafer, before amorphous layer deposition. The possibility of obtaining this goal with a dry procedure that reduces the exposure of the sample to the environment is not trivial.
We performed several dry etching processes but the best results were obtained using an etching process involving CF4/O2 gases. We have found evidence that plasma etching acts by removing the native oxide and the damaged surface of textured silicon and by leaving an active layer on silicon surface suitable for the emitter deposition. SEM analysis has confirmed that it is possible to find plasma process conditions where no appreciable damage and changes in surface morphology are induced. Detailed investigation was performed to find compatibility and optimization of amorphous layer deposition both on flat and textured cast silicon by changing the plasma process parameters. By using this process we achieved on cast silicon for solar applications photovoltaic conversion efficiencies of 12.9% on 51 cm2 and 9.2% on 45 cm2 active areas for amorphous crystalline heterostructure devices realized on monocrystalline and polycrystalline silicon respectively. We also investigated the compatibility of the process with industrial production of large area devices.
Low resistivity (5×10−4Ω cm) and high transmittance (T > 82 %) ZnO films have been obtained by RF magnetron sputtering deposition of ZnO/Al2O3 (2.5 % wt.) target. The doped oxide films have been investigated by optical and electrical measurements and by scanning electron microscopy. The optimized recipes have been applied to the realisation of amorphous p-i-n solar cells back reflector in the structure: TCO/pin/ZnO/Ag.
The application of ZnO/Ag leads to an increase of the Jsc current of about 13% but a poorer fill factor steadily affects the characteristics of the devices. We demonstrate that a thicker n+ layer of about three times the standard one is effective in driving the FF toward the normal values.
The cells' behaviour has been ascribed to a thinning of the n+ layer resulting from a sputtering action of energetic oxygen atoms during the ZnO deposition process. This effect has been evidenced by measuring the absorbance of SnO2/a-Si (20 nm) /ZnO in comparison with SnO2/a-Si (20 nm) structure.
In this paper we present an innovative diode based on the heterojunction between amorphous silicon and porous silicon grown on crystalline silicon. The device architecture gives several advantages. Deposition of amorphous silicon on porous material realises high performance junction at temperature less than 250°C and it passives the porous layer against the natural oxidation due to ageing in the environment. Porous technology allows to obtain a controlled textured silicon surface independently from crystalline silicon orientation just to give the opportunity to reduce surface reflectivity and the blue shift of the absorption spectra in solar cell application. Solar cells were characterised by I-V dark/light and quantum yield measurements. Under standard AM 1.5 light we obtained photovoltaic conversion efficiency greater than 10%. Change in photoluminescence in different gas environments showed for gas sensor applications give rise encouraging results. In dark condition we found the typical diode behaviour.
This paper reports about the fabrication and experimental test of an interferometric light intensity modulator integrated in a low loss (0.7 dB/cm), amorphous silicon based waveguide. It measures approximately 1 mm in length, while its cross section is 30-μm-wide and 3-μm-high. The device, which exploits the strong thermo-optic effect in thin film a-Si for its operation, is designed for application at the infrared wavelengths of 1.3 and 1.55 μm. The measured maximum operating on-off switching frequency of the device is 600 kHz. The very simple fabrication technology involves maximum process temperatures of 230 °C, and is therefore compatible with the standard microelectronic technology. This offers a new opportunity for the integration of optical and electronic functions on the same substrate.
Al65Cu15Co20 and Al67Cu13Co20 (% at.) alloys with composition near to the quasicrystalline decagonal phase was produced by melting in an induction furnace and solidified at room temperature. The structural characterization was carried out by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). For the structural model of decagonal quasicrsytals, it is important to know which crystalline phases have a structural relationship on the formation and decomposition of this type of phases. In the present investigation, the decagonal phase usually coexist with small amounts of the Al(Cu,Co) cubic phase of B2 type. Then, the quasicrystalline (QC) phase is outside of a single-phase region under equilibrium conditions at room temperature. DSC and TGA techniques showed the thermal stability of the alloy system up to 1000 °C.