250 research outputs found
Current-driven magnetization decrease in single crystalline ferromagnetic manganese oxide
The electrical and magnetic response to a bias current has been investigated
in a singlecrystalline ferromagnetic manganese oxide
CaMnO . A significant decrease of the magnetization is
observed at the same threshold current where a non-linearity of V-I
characteristics appears. Such a behavior cannot be understood in the framework
of the filamentary picture usually invoked for the non linearity of the other
manganese oxides. Instead, an analogy with spintronic features might be useful
and experimental signatures seem to be in agreement with excitations of spin
waves by an electric current. This provides an example of a bulk system in
which the spin polarized current induces a macroscopic change in the
magnetization.Comment: 3 pages, 4 figure
Analyse du profil de texture (tpa) et caractérisation physicochimiques des pùtes de tamarin enrichies en feuilles de moringa oleifera
Le but de cette Ă©tude Ă©tait de caractĂ©riser les propriĂ©tĂ©s physicochimiques (Aw, couleur, teneur en eau) et rhĂ©ologiques (analyse du profil de texture) des pĂątes de tamarin enrichies avec diffĂ©rentes teneurs en Moringa oleifera. Cette supplĂ©mentation permet dâaccroĂźtre la teneur protĂ©ique des produits et ainsi de participer activement au programme national de Madagascar pour la nutrition. Cette Ă©tude a permis de dĂ©finir la limite haute dâacceptabilitĂ© dâajout en Moringa oleifera. Au-delĂ dâun ajout de 30% en Moringa oleifera dans les pĂątes de tamarin, les propriĂ©tĂ©s texturales et physicochimiques sont significativement diffĂ©rentes. En parallĂšle, une Ă©tude de vieillissement des diffĂ©rents produits sur 30 jours a Ă©tĂ© rĂ©alisĂ©e. Cette Ă©tude dĂ©montre le potentiel dâexploitation industriel des pĂątes de tamarin enrichies avec 30% de Moringa oleifera. Ainsi ce produit alimentaire contribuerai activement au plan dâaction national pour la nutrition tout en valoriser les ressources naturelles de Madagascar.Mots-clĂ©s: pĂątes de fruits, Moringa oleifera, tamarin, profil de texture, propriĂ©tĂ©s physicochimiques. Texture profile analysis (tpa) and physicochemical properties study of tamarins jelly enriched with moringa olĂ©ifĂ©ra leaves The purpose of this study was to characterize the physicochemical properties (Aw, color, relative humidity) and rheological properties (texture profile analysis) of tamarind pastes enriched with different quantities of Moringa oleifera. This supplement helps to increase the protein content of the products and thus actively participate in the national program for nutrition in Madagascar. This study has identified the upper acceptability limit of adding in Moringa oleifera. Beyond the addition of 30% of Moringa oleifera in fruit pastes, textural and physicochemical properties are significantly different. In parallel, a study of aging for all the above products over 30 days was carried out. This study highlights the potential for industrial exploitation of Tamarind pastes enriched with 30% Moringa oleifera. In this way this food would contribute actively in the nation action plan of nutrition of Madagascar while encouraging the natural resources of Madagascar.Keywords: fruits pastes, Moringa oleifera, tamarin, texture profile analysis, chemicophysical properties
Small angle neutron scattering study of the step-like magnetic transformation in Pr0.70Ca0.30MnO3
Small angle neutron scattering (SANS) magnetic and electrical transport
measurements were performed to study a single crystal of Pr0.7Ca0.3MnO3, a
colossal magnetoresistive (CMR) material. While the magnetic field induced
transformation of this phase separated compound consisting of an
antiferromagnetic insulating phase (AFI) and a ferromagnetic insulating phase
(FI), is continuous at high temperature (above 5K), at lower temperature a step
like transformation is observed (around 5T at 2K). Macroscopic magnetization
measurements and SANS indicate that this transformation occurs by the formation
of mesoscopic ferromagnetic metallic (FM) domains in the AFI phase, and,
eventually, in the FI phase. Although above 5K this transformation is
continuous, below 5K a magnetization step marks the abrupt transition from a
large scale FI/AFI phase separation to a large scale phase separation between
AFI, FI and FM phases. Our results suggest that relaxation of elastic strains
inherent to the coexistence of these different phases plays a crucial role in
the mechanism of these transformations. The occurrence of magnetization steps
could result from an intrinsic behavior of the AFI phase at low temperature
Liquid-based cytology for primary cervical cancer screening: a multi-centre study
The aim of this six-centre, split-sample study was to compare ThinPrep fluid-based cytology to the conventional Papanicolaou smear. Six cytopathology laboratories and 35 gynaecologists participated. 5428 patients met the inclusion criteria (age > 18 years old, intact cervix, informed consent). Each cervical sample was used first to prepare a conventional Pap smear, then the sampling device was rinsed into a PreservCyt vial, and a ThinPrep slide was made. Screening of slide pairs was blinded (n = 5428). All non-negative concordant cases (n = 101), all non-concordant cases (n = 206), and a 5% random sample of concordant negative cases (n = 272) underwent review by one independent pathologist then by the panel of 6 investigators. Initial (blinded) screening results for ThinPrep and conventional smears were correlated. Initial diagnoses were correlated with consensus cytological diagnoses. Differences in disease detection were evaluated using McNemar's test. On initial screening, 29% more ASCUS cases and 39% more low-grade squamous intraepithelial lesions (LSIL) and more severe lesions (LSIL+) were detected on the ThinPrep slides than on the conventional smears (P = 0.001), including 50% more LSIL and 18% more high-grade SIL (HSIL). The ASCUS:SIL ratio was lower for the ThinPrep method (115:132 = 0.87:1) than for the conventional smear method (89:94 = 0.95:1). The same trend was observed for the ASCUS/AGUS:LSIL ratio. Independent and consensus review confirmed 145 LSIL+ diagnoses; of these, 18% more had been detected initially on the ThinPrep slides than on the conventional smears (P = 0.041). The ThinPrep Pap Test is more accurate than the conventional Pap test and has the potential to optimize the effectiveness of primary cervical cancer screening. © 2001 Cancer Research Campaign http://www.bjcancer.co
Dielectric catastrophe at the magnetic field induced insulator to metal transition in Pr1-xCaxMnO3 (x=0.30, 0.37) crystals
The dielectric permittivity and resistivity have been measured simultaneously
as a function of magnetic field in Pr1-xCaxMnO3 crystals with different doping.
A huge increase of dielectric permittivity was detected near percolation
threshold. The dielectric and conductive properties are found to be mutually
correlated throughout insulator to metal transition evidencing the dielectric
catastrophe phenomenon. Data are analyzed in a framework of Maxwell-Garnett
theory and the Mott-Hubbard theory attributed to the role of strong Coulomb
interactions.Comment: 5 pages, 5 figure
Annexin-A5 assembled into two-dimensional arrays promotes cell membrane repair
Eukaryotic cells possess a universal repair machinery that ensures rapid resealing of plasma membrane disruptions. Before resealing, the torn membrane is submitted to considerable tension, which functions to expand the disruption. Here we show that annexin-A5 (AnxA5), a protein that self-assembles into two-dimensional (2D) arrays on membranes upon Ca2+ activation, promotes membrane repair. Compared with wild-type mouse perivascular cells, AnxA5-null cells exhibit a severe membrane repair defect. Membrane repair in AnxA5-null cells is rescued by addition of AnxA5, which binds exclusively to disrupted membrane areas. In contrast, an AnxA5 mutant that lacks the ability of forming 2D arrays is unable to promote membrane repair. We propose that AnxA5 participates in a previously unrecognized step of the membrane repair process: triggered by the local influx of Ca2+, AnxA5 proteins bind to torn membrane edges and form a 2D array, which prevents wound expansion and promotes membrane resealing
Health and working conditions of pregnant women working inside and outside the home in Mexico City
BACKGROUND: To explore differences related to health and working conditions by comparing socio-demographic parameters, reproductive and prenatal care characteristics and working conditions among pregnant women who are employed outside the home (extra-domestic) while still performing a domestic workload versus those who perform exclusively domestic work in the home (intra-domestic). METHODS: A cross-sectional study was carried out at Family Medicine Unit N 31 of the Mexican Institute of Social Security (IMSS) in Mexico City between April and July 2003. Interviews were conducted with 537 pregnant women engaged in either extra-domestic work plus intra-domestic tasks, or those performing strictly intra-domestic work. Information was obtained regarding their demographic status, prenatal care, reproductive, work characteristics, and health during pregnancy. RESULTS: One hundred ninety-six (36.5%) of the interviewed women had paid jobs outside the home in addition to domestic tasks, while three hundred forty-one (63.5 %) engaged in exclusively intra-domestic occupations. Of the women with paid jobs, 78.6% worked as clerks. Among domestic tasks, we found that the greatest workload was associated with washing of clothes, and our micro-ergonomic analysis revealed that women who worked strictly inside the home had a higher domestic workload versus employed women (69.2 vs. 44.9%). When we analyzed the effect of work on health during pregnancy, we observed that women who worked strictly inside the home were at a higher risk for musculoskeletal and genitourinary symptoms than those employed outside the home. CONCLUSION: These findings suggest that the effect of intra-domestic work should not be ignored when considering women's health during pregnancy, and that greater attention should be paid to women's working conditions during intra and extra-domestic work
Overcoming Ostrea edulis seed production limitations to meet ecosystem restoration demands in the UN decade on restoration
The European flat oyster, Ostrea edulis, is a habitat-forming bivalve which was historically widespread throughout Europe. Following its decline due to overfishing, pollution, sedimentation, invasive species, and disease, O. edulis and its beds are now listed as a threatened and/or declining species and habitat by OSPAR. Increasing recognition of the plight of the oyster, alongside rapidly developing restoration techniques and growing interest in marine restoration, has resulted in a recent and rapid growth in habitat restoration efforts. O. edulis seed supply is currently a major bottleneck in scaling up habitat restoration efforts in Europe. O. edulis has been cultured for centuries, however, research into its culture declined following the introduction of the Pacific oyster, Crassostrea gigas to Europe in the early 1970 s. Recent efforts to renew both hatchery and pond production of O. edulis seed for habitat restoration purposes are hampered by restoration project timelines and funding typically being short, or projects not planning appropriately for the timescales required for investment, research-and-development and delivery of oyster seed by commercial producers. Furthermore, funding for restoration is intermittent, making long-term commitments between producers and restoration practitioners difficult. Long-term, strategic investment in research and production are needed to overcome these bottlenecks and meet current ambitious restoration targets across Europe
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