Exploring Vanadium Chemical Transferrin Mimetic Compounds for Insulin Enhancement

Diabetes Mellitus (DM) is caused by a lack of insulin production (Type 1) or the body’s cells’ inability to properly receive it, also known as insulin resistance (Type 2), resulting in greatly elevated levels of blood glucose. Vanadium(IV) and vanadium(V) ions are believed to enhance insulin activity by inhibition of protein tyrosine phosphatase 1B (PTP1B). PTP1B is normally responsible for downregulating the insulin signaling, but in DM type 2, PTP1B activity is overexpressed leading to the insulin signaling blocking. The most promising V(IV) compounds are designed for oral delivery: they are absorbed into the gut and delivered into the bloodstream where they are bound by the iron transporting protein serum transferrin (sTf). STf delivers the compound into cells via endocytosis, where vanadium can bind PTP1B. A limitation of these compounds is their poor stability at the stomach acidic conditions in which they undergo a significant amount of dissociation, resulting in a very inefficient gut absorption. This study explores the use of a chemical transferrin mimetic (cTfm) ligand to create V(IV) and V(V) compounds featuring excellent acidic pH stability for improved gut absorption. The cTfm-V(IV,V) compounds are expected to be labile in the pH of the bloodstream and thus the vanadium species can be quickly ligand exchanged with sTF. The cTfm ligand N,N\u27-di(o-hydroxybenzyl)ethylenediamine-N,N\u27-diacetic acid (HBED) was used to synthesize VO(IV)HBED and VO(V)HBED which demonstrated great aqueous stability in the 1-4 pH range. The role of citrate as a vehicle for delivering vanadium to sTf to regulate the transport of vanadium is also examined

Chandra Observations of ULIRGs: Extended Hot Gas Halos in Merging Galaxies

We study the properties of hot gaseous halos in 10 nearby ultraluminous IRAS galaxies observed with the ACIS instrument on board Chandra. For all sample galaxies, diffuse soft X-ray emissions are found within ~10 kpc of the central region; their spectra are well fitted by a MEKAL model plus emission lines from alpha-elements and other ions. The temperature of the hot gas is about 0.7 keV and metallicity is about 1 solar. Outside the central region, extended hot gaseous halos are found for nine out of the ten ULIRGs. Most spectra of these extended halos can be fitted with a MEKAL model with a temperature of about 0.6 keV and a low metallicity (~ 0.1 solar). We discuss the implications of our results on the origin of X-ray halos in elliptical galaxies and the feedback processes associated with starbursts.Comment: 31 pages, 6 figuers, ApJ in press, accepted versio

First-principles study of multiferroic RbFe(MoO4_4)2_2

We have investigated the magnetic structure and ferroelectricity in RbFe(MoO$_4$)$_2$ via first-principles calculations. Phenomenological analyses have shown that ferroelectricity may arise due to both the triangular chirality of the magnetic structure, and through coupling between the magnetic helicity and the ferroaxial structural distortion. Indeed, it was recently proposed that the structural distortion plays a key role in stabilising the chiral magnetic structure itself. We have determined the relative contribution of the two mechanisms via \emph{ab-initio} calculations. Whilst the structural axiality does induce the magnetic helix by modulating the symmetric exchange interactions, the electric polarization is largely due to the in-plane spin triangular chirality, with both electronic and ionic contributions being of relativistic origin. At the microscopic level, we interpret the polarization as a secondary steric consequence of the inverse Dzyaloshinskii-Moriya mechanism and accordingly explain why the ferroaxial component of the electric polarization must be small

The Management of Extrahepatic Portal Vein Aneurysms: Observe or Treat?

A case of a 70 year old man who was found to have an extrahepatic portal vein aneurysm during an evaluation for hematuria is reported. Extrahepatic portal vein aneurysms are rare with only twenty cases reported in the literature. Typically, patients present with hemorrhage requiring surgical exploration or the aneurysm is discovered during evaluation of another abdominal process. Management includes careful follow-up in the asymptomatic patient without underlying liver disease or portal hypertension

Filtragem do sêmen de garanhão para a seleção de espermatozóides móveis e aumento na taxa de fertilidade.

Foi estudado método em que o semem passa por um tratamento de filtragem que permite separar os espermatozóides móveis, melhorando as taxas de normalidade e fertilidade

Role of Ryanodine Receptors in the Assembly of Calcium Release Units in Skeletal Muscle

Abstract. In muscle cells, excitation–contraction (e–c) coupling is mediated by “calcium release units,” junctions between the sarcoplasmic reticulum (SR) and exterior membranes. Two proteins, which face each other, are known to functionally interact in those structures: the ryanodine receptors (RyRs), or SR calcium release channels, and the dihydropyridine receptors (DHPRs), or L-type calcium channels of exterior membranes. In skeletal muscle, DHPRs form tetrads, groups of four receptors, and tetrads are organized in arrays that face arrays of feet (or RyRs). Triadin is a protein of the SR located at the SR–exterior membrane junctions, whose role is not known. We have structurally characterized calcium release units in a skeletal muscle cell line (1B5) lacking Ry1R. Using immunohistochemistry and freeze-fracture electron microscopy, we find that DHPR and triadin are clustered in foci in differentiating 1B5 cells. Thin section electron microscopy reveals numerous SR–exterior membrane junctions lacking foot structures (dyspedic). These results suggest that components other than Ry1Rs are responsible for targeting DHPRs and triadin to junctional regions. However, DHPRs in 1B5 cells are not grouped into tetrads as in normal skeletal muscle cells suggesting that anchoring to Ry1Rs is necessary for positioning DHPRs into ordered arrays of tetrads. This hypothesis is confirmed by finding a “restoration of tetrads” in junctional domains of surface membranes after transfection of 1B5 cells with cDNA encoding for Ry1R

Efficacy of Integrated Straw Formulations on Lowland Rice Field Organic Carbon and Greenhouse Gas Emissions Using CCAFS-MOT Model in Niger State, Nigeria

Peer reviewedPublisher PD

Students’ engagement in school and creativity professed by students and assigned to teachers: A literature review

Este E-Book reúne um conjunto de investigações apresentadas no “I Congresso Internacional Envolvimento dos Alunos na Escola: Perspetivas da Psicologia e Educação” (ICIEAE), organizado no âmbito do “Projeto PTDC/CPE-CED/114362/2009 - Envolvimento dos Alunos na Escola: Diferenciação e Promoção” (EAE-DP), financiado pela Fundação para a Ciência e a Tecnologia (FCT).This article reviews the literature on the relation between creativity (as a personal and a contextual variable) and students’ engagement in school. In order to describe the state of art of student’s engagement in school and creativity, we prepared a narrative review. In general, literature shows a prevalence of studies relating creativity and giftedness; students with above average skills are, as a rule, characterized, among other criteria, by the presence of creativity and the existence of high motivation for learning. As a personal variable, creativity relates positively with self-concept and academic performance, appearing as an aspect worth encouraging in the student. Moreover, studies on the impact of the learning environments on student’s performance also suggest a positive relationship between the classroom climate and academic outcomes. Although studies on the relationship between creativity and the students’ behavior appear inconsistent, the teacher’s creativity, applied to the teaching-learning process, and perceived by the student, appears related to school satisfaction and academic performance. This brief review highlights the value of including creativity in teaching practices, drawing attention to the lack of studies and the need to develop research, both relational and quasi-experimental, on the relationship between creativity and students’ engagement in school and its effects

Searching for keV Sterile Neutrino Dark Matter with X-ray Microcalorimeter Sounding Rockets

High-resolution X-ray spectrometers onboard suborbital sounding rockets can search for dark matter candidates that produce X-ray lines, such as decaying keV-scale sterile neutrinos. Even with exposure times and effective areas far smaller than XMM-Newton and Chandra observations, high-resolution, wide field-of-view observations with sounding rockets have competitive sensitivity to decaying sterile neutrinos. We analyze a subset of the 2011 observation by the X-ray Quantum Calorimeter instrument centered on Galactic coordinates l = 165, b = -5 with an effective exposure of 106 seconds, obtaining a limit on the sterile neutrino mixing angle of sin^2(2 theta) < 7.2e-10 at 95% CL for a 7 keV neutrino. Better sensitivity at the level of sin^2(2 theta) ~ 2.1e-11 at 95\% CL for a 7 keV neutrino is achievable with future 300-second observations of the galactic center by the Micro-X instrument, providing a definitive test of the sterile neutrino interpretation of the reported 3.56 keV excess from galaxy clusters.Comment: 13 pages, 13 figures, submitted to Ap