286 research outputs found
Low temperature Terahertz Spectroscopy of LaFeO, PrFeO, ErFeO, and LuFeO: Quasimagnon resonances and ground multiplet transitions
We report on zone center THz excitations of non-Jahn Teller LaFeO,
PrFeO, ErFeO, and LuFeO distorted perovskites under external
magnetic fields up 7 T. Low temperature-low energy absorptions of LaFeO
show antiferromagnetic and ferromagnetic quasimagnons at AFM ~31.4 and
FM ~26.7 cm in the 4 (Gx, Ay, Fz) representation.
LuFeO is characterized by zero field magnetic resonances at AFM
~26.3 cm and FM ~22.4 cm in addition to Fe
Zeeman-split crystal field (CF) 6A ground transitions at ~10.4 cm
triggered by structural deviations induced by smaller Lu 4f. This local
non-centrosymmetric departure is also found in ErFeO (Kramers 4f
Er (4I15/2); {\Gamma}2 (Fx, Cy, Gz) <TSR ~93 K), but with the ~4
cm Fe Zeeman branching strongly biased toward higher energies.
Quasimagnons at AFM ~31.5 cm and FM ~21.5 cm in
ErFeO do not undergo field induced band splits but a 13-fold increase in
the antiferro (AMF) /ferro(AFM) intensity ratio. There is a
remarkable field-dependent CF matching population balance between Fe
higher and Er lower Zeeman branches. Antiferro- and ferro- resonances in
PrFeO turn much broader as non-Kramers Pr introduces ligand changes at
the A site leading into near degeneracy the antiferromagnetic mode and the
lowest Pr CF transition. We conclude that low energy excitations in
RFeO (R=rare earth) strongly depend on the lanthanide ionic size. Minute
lattice displacements also underlie considering non-centrosymmetric the most
distorted RFeO (R=rare earth). Changes triggered by the smaller rare earth
and the nonlinear intrinsic oxygen ion polarizability provide grounds for
interplay of ionic and electronic interactions yielding ferroelectric
spontaneous polarization.Comment: Full Manuscript and Supplemental Material, 73 pages, 27 figure
An approach to the toxicity and toxicokinetics of aflatoxin B1 and ochratoxin A after simultaneous oral administration to fasted F344 rats
Humans are exposed to the hepatotoxic aflatoxin B1 (AFB1) and nephrotoxic ochratoxin A (OTA) through diet. However, kinetic and toxicological data after their co-administration are scarce. In this study, a single oral dose of AFB1 (0.25mg/kg bw)+OTA (0.5mg/kgbw) was administered to fasted F344 rats. Blood, liver and kidney were harvested at different timepoints for mycotoxins quantification, relative weight calculation, clinical biochemistry and histopathology analysis. Toxicity parameters pointed to acute toxicity in liver due to AFB1. No remarkable toxicity was observed in kidneys or immunological organs. Maximum observed concentrations in plasma (C(max)) were at 10min and 2h for AFB1 and OTA, respectively. AFB1 plasma concentration could indicate a rapid absorption/ metabolism of the mycotoxin; and AFB1 liver and kidney concentrations were lower than LOQ and LOD, respectively. For OTA, C(max) was 4326.2μg/L in plasma. In kidney and liver C(max) was reached at 8h and concentrations were very similar between both organs at all timepoints. Due to the low levels of AFB1, the effect of OTA on AFB1 kinetics could not be assessed. However, AFB1 seems not to affect OTA kinetics, as its profile seems very similar to kinetic studies performed only with OTA in similar conditions
Manual de requerimientos minimos para intervenciones en agua, saneamiento e higiene en emergencias
Los autores realizaron el trabajo para FLASH (Formacion en Logistica, Agua, Saneamiento e Higiene
Phonons and Hybrid Modes in the High and Low Temperature Far Infrared Dynamics of Hexagonal TmMnO3
We report on TmMnO3 far infrared emissivity and reflectivity spectra from
1910 K to 4 K. At the highest temperature the number of infrared bands is lower
than that predicted for centrosymmetric P63/mmc (D6h4) (Z=2) space group due
high temperature anharmonicity and possible defect induced bitetrahedra
misalignments. On cooling, at ~1600 K TmMnO3 goes from non-polar to an
antiferroelectric-ferroelectric polar phase reaching the ferroelectric onset at
the ~700 K. The 300 K reflectivity is fitted using 19 oscillators and this
number of phonons is maintained down to 4 K. A weak phonon anomaly in the band
profile at 217 cm-1 (4 K) suggests subtle Rare Earth magnetoelectric couplings
at ~TN and below. A low energy collective excitation is identified as a THz
instability associated with room temperature eg electrons in a d-orbital
fluctuating environment. It condenses into two modes that emerge pinned to the
E-type antiferromagmetic order hardening simultaneously down to 4 K. They obey
power laws with TN as the critical temperature and match known zone center
magnons. The one peaking at 26 cm-1, with critical exponent \b{eta}=0.42 as for
antiferromagnetic order in a hexagonal lattice, is dependent on the Rare Earth.
The band at ~50 cm-1, with \b{eta}=0.25, splits at ~TN into two peaks. The
weaker band of the two is assimilated to the upper branch of gap opening in the
transverse acoustical (TA) phonon branch crossing the magnetic dispersion found
in YMnO3. (Petit et al, 2007 PRL 99, 266604). The stronger second at ~36 cm-1
corresponds to the lower branch of the TA gap. We assign both excitations as
zone center magnetoelectric hybrid quasiparticles concluding that in NdMnO3
perovskite the equivalent picture corresponds to an instability which may be
driven by an external field to transform NdMnO3 into a multiferroic compound by
perturbation enhancing the TA phonon-magnetic correlation.Comment: 39 pages, 9 Figure
High Temperature Far Infrared Dynamics of Orthorhombic NdMnO3: Emissivity and Reflectivity
We report on near normal far- and mid-infrared emission and reflectivity of
NdMnO3 perovskite from room temperature to sample decomposition above 1800 K.
At 300 K the number infrared active phonons is in close agreement with the 25
calculated for the orthorhombic D2h16-Pbnm (Z=4) space group. Their number
gradually decreases as we approach the temperature of orbital disorder at ~1023
K where the orthorhombic O' lower temperature cooperative phase coexists with
the cubic orthorhombic O. At above ~1200 K, the three infrared active phonons
coincide with the expected for cubic Pm-3m (Z=1) in the high temperature
insulating regime. Heating samples in dry air triggers double exchange
conductivity by Mn3+ and Mn4+ ions and a small polaron mid-infrared band. Fits
to the optical conductivity single out the octahedral antisymmetric and
symmetric vibrational modes as main phonons in the electron-phonon interactions
at 875 K. For 1745 K, it is enough to consider the symmetric stretching
internal mode. An overdamped defect induced Drude component is clearly outlined
at the highest temperatures. We conclude that Rare Earth manganites eg
electrons are prone to spin, charge, orbital, and lattice couplings in an
intrinsic orbital distorted perovskite lattice favoring embryonic low energy
collective excitations.Comment: 32 pages with 5 figure
Título distintivo: Guía práctica para la distribución de agua
Este manual pretende ser una guía clara y de fácil uso para poner en marcha soluciones a la escasez de
agua potable en caso de desastre natural o crisis prolongadas en los primeros momentos de la respuesta
de la emergencia o en situaciones prolongadas de escasez de agua
MMADHC Premature Termination Codons in the Pathogenesis of Cobalamin D Disorder: Potential of Translational Readthrough Reconstitution
Mutations in the MMADHC gene cause cobalamin D disorder (cblD), an autosomal recessive inborn disease with defects in intracellular cobalamin (cbl, vitamin B12) metabolism. CblD patients present methylmalonic aciduria (MMA), homocystinuria (HC), or combined MMA/HC, and usually suffer developmental delay and cognitive deficits. The most frequent MMADHC genetic alterations associated with disease generate MMADHC truncated proteins, in many cases due to mutations that create premature termination codons (PTC). In this study, we have performed a comprehensive and global characterization of MMADHC protein variants generated by all annotated MMADHC PTC mutations in cblD patients, and analyzed the potential of inducible translational PTC readthrough to reconstitute MMADHC biosynthesis. MMADHC protein truncation caused by disease-associated PTC differentially affected the alternative usage of translation initiation sites, protein abundance, and subcellular localization of MMADHC. Aminoglycoside compounds induced translational PTC readthrough of MMADHC truncated variants, allowing the biosynthesis of full-length MMADHC in a PTC-specific manner. Our results suggest that translational PTC readthrough-based interventions could complement current therapies for cblD patients carrying specific MMADHC PTC mutations.Financial support from Ikerbasque, The Basque Foundation for Science (R.P., J.C.A.-L., and J.M.C.); Ministerio de Economia, Industria y Competitividad (Spain) and FEDER (grant DPI2016-79874-R to J.C.A.-L. and J.M.C., grant SAF2016-79847-R to R.P.); Fundacion Mutua Madrilena (Spain) (grant AP169812018 to J.C.A.-L. and J.M.C). J.D.L.H. acknowledges the Biocruces Bizkaia Health Research Institute contract for Intensification of Research Activities. J.D.L.H. is a member of the European Reference Network for Rare Hereditary Metabolic Disorders (MetabERN)-Project ID No 739543. C.E.N-X. is the recipient of a Miguel Servet research contract from Instituto de Salud Carlos III (ISCIII, Spain) (CP20/00008). L.T. is the recipient of a predoctoral fellowship from Asociacion Espanola Contra el Cancer (AECC, Junta Provincial de Bizkaia, Spain). We thank to Javier Diez-Garcia (Microscopy core facility, Biocruces Bizkaia Health Research Institute) and to Gustavo Perez-Nanclares and Ana Belen de la Hoz (Genetics-Genomics core facility, Biocruces Bizkaia Health Research Institute) for their expert assistance with microscopy and DNA sequencing, respectivel
Exploring genetic factors involved in huntington disease age of onset. E2F2 as a new potential modifier gene
Age of onset (AO) of Huntington disease (HD) is mainly determined by the length of the CAG repeat expansion (CAGexp) in exon 1 of the HTT gene. Additional genetic variation has been suggested to contribute to AO, although the mechanism by which it could affect AO is presently unknown. The aim of this study is to explore the contribution of candidate genetic factors to HD AO in order to gain insight into the pathogenic mechanisms underlying this disorder. For that purpose, two AO definitions were used: the earliest age with unequivocal signs of HD (earliest AO or eAO), and the first motor symptoms age (motor AO or mAO). Multiple linear regression
analyses were performed between genetic variation within 20 candidate genes and eAO or mAO, using DNA and clinical information of 253 HD patients from REGISTRY project. Gene expression analyses were carried out by RT-qPCR with an independent sample of 35 HD patients from Basque Country Hospitals. We found suggestive association signals between HD eAO and/or mAO and genetic variation within the E2F2, ATF7IP, GRIN2A, GRIN2B, LINC01559, HIP1 and GRIK2 genes. Among them, the most significant was the association between eAO and rs2742976, mapping to the promoter region of E2F2 transcription factor.
Furthermore, rs2742976 T allele patient carriers exhibited significantly lower lymphocyte E2F2 gene expression, suggesting a possible implication of E2F2-dependent transcriptional activity in HD pathogenesis. Thus, E2F2 emerges as a new potential HD AO modifier factor
First-Trimester Sequential Screening for Preeclampsia Using Angiogenic Factors : Study Protocol for a Prospective, Multicenter, Real Clinical Setting Study
The incidence of preeclampsia (PE) is about 2-8%, making it one of the leading causes of perinatal morbidity and maternal mortality in the world. Early prophylactic low dose administration (150 mg) of acetylsalicylic acid is associated with a significant reduction in the incidence of early-onset PE, intrauterine growth restriction (IUGR), and neonatal mean stay in the intensive care unit (ICU). Universal implementation of a first-trimester screening system including angiogenic and antiangiogenic markers [the Placental Growth Factor (PlGF) and/or soluble fms-like Tyrosine Kinase-1 (sFlt-1)] has shown a prediction rate of 90% for early-onset PE but entails a high financial cost. The aim of this study is to determine the predictive and preventive capacity of a universal PE first-trimester two-step sequential screening model, determining the PlGF only in patients previously classified as intermediate risk by means of a multivariate model based on resources already used in the standard pregnancy control, in a real clinical setting. We hypothesize that this screening model will achieve similar diagnostic performance as the universal determination of PlGF but at a lower economic cost. This is a prospective, multicentric, cohort study in a real-world clinical setting. Every singleton pregnancy will be recruited at the routine first pregnancy visit. In a first step, the first-trimester risk of PE will be calculated using a multivariate Gaussian distribution model, based on medical history, mean blood pressure, Pregnancy-Associated Plasma Protein A (PAPP-A), and Uterine Artery Doppler Pulsatility Index (UTPI). Patients will be classified into three risk groups for PE: (1) risk ≥ 1/50, high-risk with no further testing (blinded PlGF); (2) risk between 1/51 and 1/500, medium-risk requiring further testing; and (3) risk ≤ 1/501, low-risk with no further testing. In a second step, the PlGF will only be determined in those patients classified as intermediate risk after this first step, and then reclassified into high- or low-risk groups. Prophylactic administration of aspirin (150 mg/day) will be prescribed only in high risk patients. As a secondary objective, sFlt-1 values will be blindly determined in patients with high and intermediate risk to assess its potential performance in the screening for PE. The study will be conducted in accordance with the principles of Good Clinical Practice. This study is approved by the Aragon Research Ethics Committee (CEICA) on 3 July 2020 (15/2020). , identifier: NCT04767438
- …