464 research outputs found
Vitamin E (α-tocopherol) supplementation in diabetic rats: effects on the proximal colon
<p>Abstract</p> <p>Background</p> <p>Neuropathy is one of the complications caused by diabetes mellitus which is directly related to the gastrointestinal manifestations of the disease. Antioxidant substances, such as vitamin E, may play an important role in the reduction of the neurological damage caused by diabetes mellitus. The aim of the present study was to determine whether vitamin E (α-tocopherol) at different concentrations induces any effects on the morphology of the intestinal wall and intrinsic innervation in the proximal colon of diabetic rats.</p> <p>Methods</p> <p>Thirty rats (90-day-old) were assigned to the following groups: N (normoglycemic), NE1 (normoglycemic supplemented with vitamin E 0.1%), NE2 (normoglycemic supplemented with vitamin E 2%), D (diabetic), DE1 (diabetic supplemented with vitamin E 0.1%), and DE2 (diabetic supplemented with vitamin E 2%). Animals received vitamin E supplementation for 120 days and were sacrificed when they were 210 days old. The proximal colon of each animal was subjected to histology to study the intestinal wall and goblet cells and processed for whole-mount preparations to morphoquantitatively determine the total myenteric population.</p> <p>Results</p> <p>Supplementation with vitamin E significantly reduced glycemia and glycated hemoglobin values and preserved the number of myenteric neurons in group DE2, without affecting intestinal area or thickness of the intestinal wall or muscular tunic.</p> <p>Conclusion</p> <p>Vitamin E (2%) influenced the glycemic parameters and had a neuroprotective effect on the total myenteric population, but the morphometric characteristics of the intestinal wall were unaffected.</p
Black hole mass and spin measurements through the Relativistic Precession Model: XTE J1859+226
The X-ray light curves of accreting black holes and neutron stars in binary
systems show various types of quasi-periodic oscillations (QPOs), the origin of
which is still debated. The Relativistic Precession Model identifies the QPO
frequencies with fundamental time scales from General Relativity, and has been
proposed as a possible explanation of certain types of such oscillations. Under
specific conditions (i.e., the detection of a particular QPOs triplet) such a
model can be used to obtain self-consistent measurements of the mass and spin
of the compact object. So far this has been possible only in the black hole
binary GRO J1655-40. In the RXTE/PCA data from the 1999-2000 outburst of the
black hole transient XTE J1859+226 we found a QPO triplet, and used the the
Relativistic Precession Model to obtain high-precision measurements of the
black hole mass and spin - M = (7.85+/-0.46) Msun, a* = 0.149+/-0.005 - the
former being consistent with the most recent dynamical mass determination from
optical measurements. Similarly to what has been already observed in other
black hole systems, the frequencies of the QPOs and broad-band noise components
match the general relativistic frequencies of particle motion close to the
compact object predicted by the model. Our findings confirm previous results
and further support the validity of the Relativistic Precession Model, which is
the only electromagnetic-measurement-based method that so far has consistently
yielded spins close to those from the gravitational waves produced by merging
binary black holes.Comment: 8 pages, 5 figures, accepted for publication in MNRA
Evidence for a black hole in the historical X-ray transient A 1524-61 (=KY TrA)
We present VLT spectroscopy, high-resolution imaging and time-resolved
photometry of KY TrA, the optical counterpart to the X-ray binary A 1524-61. We
perform a refined astrometry of the field, yielding improved coordinates for KY
TrA and the field star interloper of similar optical brightness that we locate
arcsec SE. From the spectroscopy, we refine the radial velocity
semi-amplitude of the donor star to km s by employing
the correlation between this parameter and the full-width at half-maximum of
the H emission line. The -band light curve shows an ellipsoidal-like
modulation with a likely orbital period of d (
h). These numbers imply a mass function M. The
KY TrA de-reddened quiescent colour is consistent
with a donor star of spectral type K2 or later, in case of significant
accretion disc light contribution to the optical continuum. The colour allows
us to place a very conservative upper limit on the companion star mass, M, and, in turn, on the binary mass ratio, . By exploiting the correlation between the binary inclination and the
depth of the H line trough, we establish deg. All these
values lead to a compact object and donor mass of
M and M, respectively, thus confirming the
black hole nature of the accreting object. In addition, we estimate a distance
toward the system of kpc.Comment: 7 pages, 5 figure
The orbital period, black hole mass and distance to the X-ray transient GRS 1716-249 (=N Oph 93)
We present evidence for a 0.278(8) d (=6.7 h) orbital period in the X-ray
transient GRS 1716-249 (=N Oph 93), based on a superhump modulation detected
during the 1995 mini-outburst plus ellipsoidal variability in quiescence. With
a quiescent magnitude of r=23.19+-0.15 N Oph 93 is too faint to warrant a full
dynamical study through dedicated time-resolved spectroscopy. Instead, we apply
the FWHM-K2 correlation to the disc Halpha emission line detected in Gran
Telescopio Canarias spectra and obtain K2=521+-52 km/s. This leads to a mass
function f(M)=4.1+-1.2 Msun, thus indicating the presence of a black hole in
this historic X-ray transient. Furthermore, from the depth of the Halpha trough
and the quiescent light curve we constrain the binary inclination to i=61+-15
deg, while the detection of superhumps sets an upper limit to the donor to
compact star mass ratio q=M2/M1<=0.25. Our de-reddened (r-i) colour is
consistent with a ~K6 main sequence star that fills its Roche lobe in a 0.278 d
orbit. Using all this information we derive a compact object mass
M1=6.4+3.2-2.0 Msun at 68 per cent confidence. We also constrain the distance
to GRS 1716-249 to 6.9+-1.1 kpc, placing the binary ~0.8 kpc above the Galactic
Plane, in support of a large natal kick.Comment: Accepted for publication in MNRAS, 12 pages, 9 figures, 2 Table
Healthy climate and energy savings: using thermal ceramic panels and solar thermal panels in mediterranean housing blocks
Radiant surface conditioning systems based on capillary tube mats not only provide high standards of comfort, but they also generate substantial energy savings. These systems allow for using renewable energies such as solar thermal panels because they function with water at moderate
temperatures¿lower in winter and higher in summer¿compared to fan-coil systems or hot water radiator systems. Moreover, in summer, they can be combined with solar cooling systems based on lithium chloride or absorption systems based on lithium bromide, which enable the cooling of water at 15¿16 C by means of solar thermal panel energy collection. This further reduces the annual energy.
The purpose of this study was to examine the application of thermal ceramic panels (TCP) containing prolipropylen (PPR) capillary tube mats, in residential buildings in the Spanish Mediterranean.
The water distribution system was set up individually from a heat pump and was combined with a community system of solar thermal panels. After monitoring a home over a complete one-year cycle, the annual energy demand was quantified through simulations, based on both the radiant
system and the VRV system, as well as in combination with a thermal solar panel system. TCP panels reduced the annual energy demands by 31.48%, and the additional investment cost of 11,497 could be amortized over 23.31 years. The combination of TCP panels with 18.5 m2 of solar thermal panels reduced the annual energy demand by 69.47%, and the inv
Assessment of Some Trace Chemical Elements in Cajío Beach Peloid Using Nuclear Analytical Techniques
A peloid is a maturated mud or muddy dispersion with healing and/or cosmetic properties, composed of a complex mixture of fine-grained natural materials of geologic and/or biologic origin, mineral water or seawater, and common organic compounds from biological metabolic activity. Cajio beach peloid is a traditional peloid of the south coast of Güira de Melena municipality located in Artemisa province, Cuba. The peloid is a sea mud, used in situ, by the population of the locality. The present study has tree aims: ones is to determine trace chemical elements content (Sc, Cs, La, Ce, Nd, Sm, Eu, Gd, Tb, Tm, Yb, Hf, Ta, Th and U). The second aim is to determine natural (226Ra, 238U, 232Th, 210Pb, 40K) and the anthropogenic (137Cs) radionuclides in the peloid. Finally, to assess the level of contamination and radiological risk for the users of the peloid therapeutic practices
Evaluation of Fattening Efficiency of Grazing Bulls through Panel Data Envelop Analysis
The purpose of this paper was to assess fattening efficiency changes in grazing bulls, using panel data envelop analysis in two periods of time. The panel data were compiled by DEAP 2.1, which included the results of a 3-year period from 38 private farms (beef farms) in cooperatives of credits and services. The farms were on prairie savannahs, located on 21.4831 latitude, and -77.3174 longitude, less than 300 meters above sea level, province of Camagüey, mideastern Cuba. The output variable was total sold kg (TSKG), and the input variables were cost of Norgold (CN), fuel kg per ha (FKGXHA), fuel kg per livestock unit (FKGXLU), and unit of human labor force (UHL), which were highly correlated to the output variable. Table 2 shows that technical efficiency (TE), pure efficiency (PEC), and scale sufficiency (SEC), underwent 0.2%, 0.4, and 0.5%, respectively, by the third year of fattening. Technological change (TC) between the second and third years rose to almost 14%, and the total productivity factor (TPF) spiked as farmers became more skilled and experienced, with a 4.9% increase in comparison to the first year, and 13.7% in the second year
Willingness to pay for biofertilizers among grain legume farmers in northern Ghana
Open Access Journal; Published online: 27 April 2018Background: The call for use of improved Soil Fertility Management (SFM) technologies is a prerequisite to increase agricultural productivity among farmers. This study assessed farmers’ willingness to pay (WTP) for selected financially rewarding biofertilizer technologies/packages for legume production in northern Ghana. Primary data was elicited from 400 grain legume farmers
selected from Northern and Upper West Regions of Ghana through a simple random sampling technique. The double bounded dichotomous choice (DBDC) format of contingent valuation approach was employed to elicit willingness to pay values and determinants of farmers WTP was evaluated using the maximum likelihood estimation procedure.
Results: The results showed that about 60%, 25% and 46% of soya, cowpea and groundnuts farmers were willing to pay for the selected biofertilizers (Biofix, BR3267 and Legumefix respectively) at prices not exceeding GHC 14.00, GHC 28.00 and GHC 20.00 per 0.2kg of the respective biofertilizers. Legume farmers in Northern Region were however willing to pay higher for the three biofertilizer technologies as compared to their counterparts in Upper West Region. For 0.2 kg each of Biofix, BR3267 and Legumefix, farmers in Northern Region were willing to pay approximately GHC 17.00, GHC 12.00 and GHC 23.00 respectively whereas those in Upper West Region were willing to pay GHC 14.00, GHC 9.00 and GHC 11.00 for the same quantity of each
biofertilizer. The study identified farming experience, FBO membership, awareness and previous use of biofertilizers as significant determinants of farmers’ willingness to pay for Biofertilizers.
Conclusion: Comparatively, mean prices farmers are willing to pay for these three technologies are below ex-factory prices, hence subsidizing the cost of production of these biofertilizers in the initial stages would be relevant for improving farmers’ uptake of these fertilizers. Sustained awareness creation through periodic education and sensitization by using FBOs as leverage points
is also highly recommended to improve farmers’ understanding of the concept of biofertilizer use
Phosphorylation of Syntaxin‐1a by casein kinase 2α (CK2α) regulates presynaptic vesicle exocytosis from the reserve pool
The t-soluble NSF-attachment protein receptor protein Syntaxin-1a (Stx-1a) is abundantly expressed at pre-synaptic terminals where it plays a critical role in the exocytosis of neurotransmitter-containing synaptic vesicles. Stx-1a is phosphorylated by Casein kinase 2α (CK2α) at Ser14, which has been proposed to regulate the interaction of Stx-1a and Munc-18 to control of synaptic vesicle priming. However, the role of CK2α in synaptic vesicle dynamics remains unclear. Here, we show that CK2α over-expression reduces evoked synaptic vesicle release. Furthermore, shRNA-mediated knockdown of CK2α in primary hippocampal neurons strongly enhanced vesicle exocytosis from the reserve pool, with no effect on the readily releasable pool of primed vesicles. In neurons in which endogenous Stx-1a was knocked down and replaced with a CK2α phosphorylation-deficient mutant, Stx-1a(D17A), vesicle exocytosis was also increased. These results reveal a previously unsuspected role of CK2α phosphorylation in specifically regulating the reserve synaptic vesicle pool, without changing the kinetics of release from the readily releasable pool
Bmi1 Confers Resistance to Oxidative Stress on Hematopoietic Stem Cells
The polycomb-group (PcG) proteins function as general regulators of stem cells. We previously reported that retrovirus-mediated overexpression of Bmi1, a gene encoding a core component of polycomb repressive complex (PRC) 1, maintained self-renewing hematopoietic stem cells (HSCs) during long-term culture. However, the effects of overexpression of Bmi1 on HSCs in vivo remained to be precisely addressed.In this study, we generated a mouse line where Bmi1 can be conditionally overexpressed under the control of the endogenous Rosa26 promoter in a hematopoietic cell-specific fashion (Tie2-Cre;R26Stop(FL)Bmi1). Although overexpression of Bmi1 did not significantly affect steady state hematopoiesis, it promoted expansion of functional HSCs during ex vivo culture and efficiently protected HSCs against loss of self-renewal capacity during serial transplantation. Overexpression of Bmi1 had no effect on DNA damage response triggered by ionizing radiation. In contrast, Tie2-Cre;R26Stop(FL)Bmi1 HSCs under oxidative stress maintained a multipotent state and generally tolerated oxidative stress better than the control. Unexpectedly, overexpression of Bmi1 had no impact on the level of intracellular reactive oxygen species (ROS).Our findings demonstrate that overexpression of Bmi1 confers resistance to stresses, particularly oxidative stress, onto HSCs. This thereby enhances their regenerative capacity and suggests that Bmi1 is located downstream of ROS signaling and negatively regulated by it
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