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1.
Phys Rev Lett ; 129(21): 217202, 2022 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-36461963

RESUMO

Yb_{2}Ti_{2}O_{7} is a celebrated example of a pyrochlore magnet with highly frustrated, anisotropic exchange interactions. To date, attention has largely focused on its unusual, static properties, many of which can be understood as coming from the competition between different types of magnetic order. Here we use inelastic neutron scattering with exceptionally high energy resolution to explore the dynamical properties of Yb_{2}Ti_{2}O_{7}. We find that spin correlations exhibit dynamical scaling, analogous to behavior found near to a quantum critical point. We show that the observed scaling collapse can be explained within a phenomenological theory of multiple-phase competition, and confirm that a scaling collapse is also seen in semiclassical simulations of a microscopic model of Yb_{2}Ti_{2}O_{7}. These results suggest that dynamical scaling may be general to systems with competing ground states.

2.
J Dairy Sci ; 104(4): 4929-4935, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33663827

RESUMO

This study estimates the accuracy of the focused lung ultrasound (FLUS) compared with systematic thoracic ultrasonography (TUS) as the reference test for diagnosing pneumonia in pre- and postweaned dairy calves. One hundred thirty-five Holstein Friesian calves, aged between 1 to 6 mo were enrolled and were kept in the same pen with one or more animals showing signs of bovine respiratory disease complex (BRDC). One operator performed FLUS on each calf, and then a second, blinded operator performed TUS on the same calf. For the FLUS, we only scanned the lung lobes that are most frequently affected during BRDC and are thus easier to detect, such as the caudal aspect of the cranial lobe of the left lung (fifth and fourth left intercostal spaces; ICS), the middle lobe of the right lung (fifth right ICS), and the caudal aspect of the cranial lobe of the right lung (fourth right ICS). Pneumonia was diagnosed when a calf had a minimum of one small lobular lung lesion that was at least 1 cm deep within a normally aerated lobe (TUS score of ≥2). Diagnostic accuracy indexes of the FLUS were calculated using TUS as the gold standard. The McNemar test was performed to evaluate the differences between the 2 techniques. In addition, an intertest agreement was assessed using the weighted kappa test. A total of 76 out of 135 calves had a TUS score of ≥2 and were therefore considered to be affected by BRDC. The FLUS had a sensitivity of 81.6% (95% CI = 71.0-89.5%), specificity = 100% (95% CI = 93.9-100%), positive predictive value was 100%, negative predictive value was 96.6% (95% CI = 94.7---97.9%), and accuracy was 97% (95% CI = 92.6-99.2%). The McNemar test highlighted a difference of 10.3% between the FLUS and TUS. The agreement between the TUS and FLUS was substantial (weighted kappa test 0.78). Although FLUS shows some limitations in diagnosing lung lesions associated with BRDC compared with the systematic approach, this study shows that the focused method could be used as an additional tool for evaluating consolidation, especially when examining a large number of postweaned dairy calves.


Assuntos
Complexo Respiratório Bovino , Pneumopatias , Doenças Respiratórias , Animais , Bovinos , Pulmão/diagnóstico por imagem , Pneumopatias/diagnóstico por imagem , Pneumopatias/veterinária , Doenças Respiratórias/veterinária , Ultrassonografia/veterinária
3.
Hum Reprod ; 35(4): 759-769, 2020 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-32242613

RESUMO

STUDY QUESTION: Is de novo segmental aneuploidy (SA) a biological event or an artifact that is erroneously interpreted as partial chromosome imbalance? SUMMARY ANSWER: The detection of de novo SA in sequential biopsies of preimplantation embryos supports the biological nature of SA. WHAT IS KNOWN ALREADY: Although some SAs are detected in oocytes and in blastocysts, the highest incidence is observed in cleavage-stage embryos. Based on these findings, we can postulate that the majority of cells affected by SAs are eliminated by apoptosis or that affected embryos mainly undergo developmental arrest. STUDY DESIGN, SIZE, DURATION: This retrospective study includes 342 preimplantation genetic testing for aneuploidy (PGT-A) cycles performed between January 2014 and December 2018. Chromosome analysis was performed on 331 oocytes, 886 cleavage-stage embryos and 570 blastocysts (n = 1787). From 268 expanded blastocysts, the blastocoelic fluid (BF) was also analyzed (resulting in 2025 samples in total). In cases of SAs involving loss or gain in excess of 15 Mb, embryos were not considered for transfer and sequential biopsies were performed at following stages. This resulted in 66 sets where the initial diagnosis of SAs (4 made in polar bodies, 25 in blastomeres and 37 in trophectoderm (TE) cells) was followed up. PARTICIPANTS/MATERIALS, SETTING, METHODS: A total of 2082 samples (2025 + 27 whole embryos) were processed by whole genome amplification followed by array comparative genomic hybridization. MAIN RESULTS AND THE ROLE OF CHANCE: The incidence of SAs was 6.3% in oocytes, increased to 16.6% in cleavage-stage embryos (P < 0.001) and decreased to 11.2% in blastocysts (P < 0.025 versus oocytes; P < 0.01 versus cleavage-stage embryos). The highest incidence of SAs was found in BFs (26.1%, P < 0.001). The analysis of 66 sets of sequential biopsies revealed that the initial finding was confirmed in all following samples from 39 sets (59.1% full concordance). In 12 additional sets, SAs were detected in some samples while in others the interested chromosome had full aneuploidy (18.2%). In three more sets, there was a partial concordance with the initial diagnosis in some samples, but in all TE samples the interested chromosome was clearly euploid (4.5%). In the remaining 12 sets, the initial SA was not confirmed at any stage and the corresponding chromosomes were euploid (18.2% no concordance). The pattern of concordance was not affected by the number of SAs in the original biopsy (single, double or complex) or by the absence or presence of concomitant aneuploidies for full chromosomes. LIMITATIONS, REASONS FOR CAUTION: Chromosome analyses were performed on biopsies that might not be representative of the true constitution of the embryo itself due to the occurrence of mosaicism. WIDER IMPLICATIONS OF THE FINDINGS: The permanence of SAs throughout the following stages of embryo development in more than half of the analyzed sets suggests for this dataset a very early origin of this type of chromosome imbalance, either at meiosis or at the first mitotic divisions. Since SAs remained in full concordance with the initial diagnosis until the blastocyst stage, a corrective mechanism seems not to be in place. In the remaining cases, it is likely that, as for full chromosome aneuploidy, mosaicism derived from mitotic errors could have occurred. In following cell divisions, euploid cell lines could prevail preserving the embryo chances of implantation. Due to the scarcity of data available, the transfer of embryos with SAs should be strictly followed up to establish possible clinical consequences related to this condition. STUDY FUNDING/COMPETING INTEREST(S): No specific funding was obtained. There are no conflicts of interest.


Assuntos
Diagnóstico Pré-Implantação , Aneuploidia , Biópsia , Blastocisto , Hibridização Genômica Comparativa , Feminino , Humanos , Gravidez , Estudos Retrospectivos
4.
Phys Rev Lett ; 124(8): 087206, 2020 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-32167347

RESUMO

We report time-of-flight neutron spectroscopy and neutron and x-ray diffraction studies of the 5d^{2} double perovskite magnets, Ba_{2}MOsO_{6} (M=Zn,Mg,Ca). These materials host antiferromagnetically coupled 5d^{2} Os^{6+} ions decorating a face-centered cubic (fcc) lattice and are found to remain cubic down to the lowest temperatures. They all exhibit thermodynamic anomalies consistent with a single phase transition at a temperature T^{*}, and a gapped magnetic excitation spectrum with spectral weight concentrated at wave vectors typical of type-I antiferromagnetic orders. However, while muon spin resonance experiments show clear evidence for time-reversal symmetry breaking below T^{*}, we observe no corresponding magnetic Bragg scattering signal. These results are shown to be consistent with ferro-octupolar symmetry breaking below T^{*}, and are discussed in the context of other 5d double perovskite magnets and theories of exotic orders driven by multipolar interactions.

5.
J Dairy Sci ; 103(9): 8554-8563, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32684447

RESUMO

The conjugated linoleic acid (CLA) isomers, a group of naturally occurring isomers of the essential fatty acid (FA) linoleic acid, have received special attention in animal and human nutrition. Although they have long been used as dietary integrators in dairy cows, the effects of CLA isomers on bovine immune cells remain mostly undisclosed. The present study aimed to cover this gap and investigate the in vitro effects of CLA on inflammatory functions, including chemotaxis, phagocytosis, killing capability, and extracellular respiratory burst of purified bovine monocytes (CD14+). The apoptosis rate of monocytes was addressed as well. Once assessed, the effects of different concentrations (10, 50, 100, and 500 µM) of the 2 main CLA isomers, namely cis-9,trans-11 and trans-10,cis-12, the experiments were carried out using a concentration of 50 µM of the CLA isomers, both individually and in a mixture (50:50). The immunomodulatory activities of linoleic acid, an essential FA, and stearic acid, a saturated FA, were also investigated. Only the 50:50 CLA mixture was able to reduce monocyte apoptosis and to increase the extracellular respiratory burst during experimental proinflammatory conditions, as assessed by measuring production of reactive oxygen species. Linoleic acid and CLA had no effects on chemotaxis, phagocytosis, or killing capability. Remarkably, treatment of monocytes with stearic acid significantly reduced their chemotactic capability. The present results demonstrated that CLA isomers do have immunomodulatory effects on some functions of bovine monocytes, and that the mixture of the 2 CLA isomers is more effective than the CLA isomers individually.


Assuntos
Inflamação/metabolismo , Ácidos Linoleicos Conjugados/farmacologia , Monócitos/efeitos dos fármacos , Explosão Respiratória/fisiologia , Animais , Bovinos , Dieta/veterinária , Relação Dose-Resposta a Droga , Feminino , Ácidos Linoleicos Conjugados/administração & dosagem , Monócitos/metabolismo , Espécies Reativas de Oxigênio
6.
Phys Rev Lett ; 123(2): 027201, 2019 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-31386489

RESUMO

The quantum dimer magnet (QDM) is the canonical example of quantum magnetism. The QDM state consists of entangled nearest-neighbor spin dimers and often exhibits a field-induced triplon Bose-Einstein condensate (BEC) phase. We report on a new QDM in the strongly spin-orbit coupled, distorted honeycomb-lattice material Yb_{2}Si_{2}O_{7}. Our single crystal neutron scattering, specific heat, and ultrasound velocity measurements reveal a gapped singlet ground state at zero field with sharp, dispersive excitations. We find a field-induced magnetically ordered phase reminiscent of a BEC phase, with exceptionally low critical fields of H_{c1}∼0.4 and H_{c2}∼1.4 T. Using inelastic neutron scattering in an applied magnetic field we observe a Goldstone mode (gapless to within δE=0.037 meV) that persists throughout the entire field-induced magnetically ordered phase, suggestive of the spontaneous breaking of U(1) symmetry expected for a triplon BEC. However, in contrast to other well-known cases of this phase, the high-field (µ_{0}H≥1.2 T) part of the phase diagram in Yb_{2}Si_{2}O_{7} is interrupted by an unusual regime signaled by a change in the field dependence of the ultrasound velocity and magnetization, as well as the disappearance of a sharp anomaly in the specific heat. These measurements raise the question of how anisotropy in strongly spin-orbit coupled materials modifies the field induced phases of QDMs.

7.
J Assist Reprod Genet ; 36(11): 2297, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31631238

RESUMO

The original article unfortunately contained a mistake. The names of the collaborators were captured as authors of the article.

8.
J Assist Reprod Genet ; 36(11): 2287-2295, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31463873

RESUMO

PURPOSE: To estimate the contribution of cryopreservation to the cumulative live birth rate (CLBR) after law modification in Italy in the era of vitrification and freeze-all. METHODS: The Italian National Registry performed a cycle-based data collection. Nine Italian IVF clinics were involved incorporating a total of 10,260 fresh cycles performed between January 2015 and April 2016 resulting in 9273 oocyte retrievals and 3266 subsequent warming cycles from the same oocyte retrievals performed up to December 2016. Mean female age was 37 ± 4.3 years. Primary outcome measure was CLBR per oocyte retrieval. Confounding factors were tested in multivariate regression analysis, and the relative impact of cryopreservation to the CLBR in different patient categories was calculated. RESULTS: CLBR per oocyte retrieval was 32.6%, 26.5%, 18.7%, 13.0%, and 5.5% for women younger than 36, aged 36-39, 40-41, and older than 41 years, respectively. The total relative contribution of oocyte/embryo cryopreservation was 40.6% (95% CI 38.41-42.75). An association between maternal age, number of oocytes retrieved, fertilization rate, cryopreservation, and cumulative live birth was shown. When adjusted for confounders, a 2.3-fold increase was observed in the chance of live birth when cryopreservation was performed (OR 2.3; 95% CI 1.99-2.56). In high responder patients (> 15 oocytes retrieved) where freeze-all was applied in 67.6% of cycles to avoid the risk of hyper stimulation syndrome, the relative contribution of vitrification to the CLBR was 80.6%. CONCLUSIONS: Cryopreservation is essential in IVF and should always be available to patients to optimize success rates. Multicentric, cycle-based data analyses are crucial to provide infertile couples, clinicians, and regulatory bodies with accurate information on IVF effectiveness including fresh and cryopreserved cycles.

9.
Org Biomol Chem ; 16(36): 6708-6717, 2018 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-30182115

RESUMO

Five new cyclic peptoids containing (2S,4R)-4-hydroxyproline (Hyp) residues have been designed and synthesized using a mixed "submonomer/monomer" approach. Alkali metal cation affinities and ion transport activities were assessed by experimental (NMR and HPTS assay in liposomes) and computational methods. Easy functionalization of hydroxyproline residues afforded a bouquet of cyclic oligomers showing correlation between ion transport abilities and cytotoxic activities on selected human cancer cell lines.


Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Materiais Biomiméticos/química , Materiais Biomiméticos/farmacologia , Hidroxiprolina/química , Peptoides/química , Peptoides/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Humanos , Sódio/química
10.
Org Biomol Chem ; 15(46): 9932-9942, 2017 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-29164219

RESUMO

Most of the structural studies made on the secondary structure of peptoids describe their geometric attributes in terms of the classic Ramachandran plot (based on the local analysis of ω, ψ, χ, φ dihedral angles). However, little intuitive understanding is available from internal coordinates when stereochemistry is involved. In this contribution we list all the conformationally stable cyclic peptoids reported up to the year 2017 and propose a simple method to define their geometric arrangement in terms of planar chirality. Evidence of conformational isomerism (due to the long average time of single bond rotation) and conformational chirality (induced by the absence of roto-reflection axes) in this promising class of synthetic macrocycles is provided by NMR spectroscopy (using Pirkle's alcohol as chiral solvating agent) and careful evaluation of X-ray crystallographic studies. The full understanding of the oligomeric macrocycles' structural properties and the clear framing of their conformational isomerism in a proper conceptual scheme is fundamental for future application of peptoids in asymmetric synthesis, chiral recognition and supramolecular chemistry.


Assuntos
Peptoides/química , Cristalografia por Raios X , Modelos Moleculares , Conformação Proteica , Estereoisomerismo
11.
J Prev Med Hyg ; 58(2): E121-E129, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28900352

RESUMO

INTRODUCTION: Patient safety and quality in healthcare are inseparable. Examining patient safety culture in staff members contributes to further develop quality in healthcare. In Italy there has been some experience in assessing patient safety culture in staff working in hospital. In this pilot study we explored patient safety culture in public health staff working in Italian Local Health Authorities. METHODS: We carried out a descriptive cross sectional study in four Italian territorial Prevention facilities in Northern Italy. We administrated an adapted Italian version of the US Hospital Survey of Patient Safety Culture to all the staff within these facilities. The survey consisted of 10 dimensions based on 33 items, according to the results of a previous psychometric validation. RESULTS: Seventy per cent of the staff responded to the survey (N = 479). Overall, six out of the 10 dimensions exhibited composite scores of positive response frequency for patient safety culture below 50%. While "communication openness" (65%) was the most developed factor, "teamwork across Units" (37%) was the least developed. The work areas with the highest composite scores were Management and the Public Health Laboratory, while in terms of professional categories, Physicians had the highest scores. Patient safety culture in the staff participating in this study was lower than in hospital staff. DISCUSSION: Our descriptive cross sectional study is the first to be carried out in Preventive medicine settings in Italy. It has clearly indicated the need of improvement. Consequently, several interventions with this aim have been implemented.


Assuntos
Atitude do Pessoal de Saúde , Segurança do Paciente , Medicina Preventiva/normas , Qualidade da Assistência à Saúde , Gestão da Segurança , Adulto , Estudos Transversais , Humanos , Itália , Projetos Piloto , Inquéritos e Questionários
12.
Org Biomol Chem ; 14(38): 9055-9062, 2016 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-27714208

RESUMO

An efficient protocol for the solid-phase synthesis of six members of a new class of extended macrocyclic peptoids (based on ortho-, meta- and para-N-(methoxyethyl)aminomethyl phenylacetyl units) is described. Theoretical (DFT) and experimental (NMR) studies on the free and Na+-complexed cyclic trimers (3-5) and tetramers (6-8) demonstrate that annulation of the rigidified peptoids can generate new hosts with the ability to sequestrate one or two sodium cations with the affinities and stoichiometries defined by the macrocycle morphology. Ion transport studies have been also performed in order to better appreciate the factors promoting transmembrane cation translocation.


Assuntos
Compostos de Benzil/síntese química , Ionóforos/síntese química , Compostos Macrocíclicos/síntese química , Peptoides/síntese química , Compostos de Benzil/química , Ciclização , Transporte de Íons , Ionóforos/química , Compostos Macrocíclicos/química , Modelos Moleculares , Peptoides/química , Sódio/química
13.
Nat Mater ; 13(5): 488-93, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24728463

RESUMO

The idea of magnetic monopoles in spin ice has enjoyed much success at intermediate temperatures, but at low temperatures a description in terms of monopole dynamics alone is insufficient. Recently, numerical simulations were used to argue that magnetic impurities account for this discrepancy by introducing a magnetic equivalent of residual resistance in the system. Here we propose that oxygen deficiency is the leading cause of magnetic impurities in as-grown samples, and we determine the defect structure and magnetism in Y2Ti2O7-δ using diffuse neutron scattering and magnetization measurements. These defects are eliminated by oxygen annealing. The introduction of oxygen vacancies causes Ti(4+) to transform to magnetic Ti(3+) with quenched orbital magnetism, but the concentration is anomalously low. In the spin-ice material Dy2Ti2O7 we find that the same oxygen-vacancy defects suppress moments on neighbouring rare-earth sites, and that these magnetic distortions markedly slow down the long-time monopole dynamics at sub-Kelvin temperatures.

14.
Opt Express ; 23(19): A1030-9, 2015 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-26406733

RESUMO

Fresnel lenses used as primary optics in concentrating photovoltaic modules may show warping produced by lens manufacturing or module assembly (e.g., stress during molding or weight load) or due to stress during operation (e.g., mismatch of thermal expansion between different materials). To quantify this problem, a simple method called "checkerboard method" is presented. The proposed method identifies shape errors on the front surface of primary lenses by analyzing the Fresnel reflections. This paper also deals with the quantification of the effects these curvatures have on their optical performance and on the electrical performance of concentrating modules incorporating them. This method can be used to perform quality control of Fresnel lenses in scenarios of high volume production.

15.
Nature ; 455(7212): 503-5, 2008 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-18818651

RESUMO

Highly luminous rapid flares are characteristic of processes around compact objects like white dwarfs, neutron stars and black holes. In the high-energy regime of X-rays and gamma-rays, outbursts with variabilities on timescales of seconds or less are routinely observed, for example in gamma-ray bursts or soft gamma-ray repeaters. At optical wavelengths, flaring activity on such timescales has not been observed, other than from the prompt phase of one exceptional gamma-ray burst. This is mostly due to the fact that outbursts with strong, fast flaring are usually discovered in the high-energy regime; most optical follow-up observations of such transients use instruments with integration times exceeding tens of seconds, which are therefore unable to resolve fast variability. Here we show the observation of extremely bright and rapid optical flaring in the Galactic transient SWIFT J195509.6+261406. Our optical light curves are phenomenologically similar to high-energy light curves of soft gamma-ray repeaters and anomalous X-ray pulsars, which are thought to be neutron stars with extremely high magnetic fields (magnetars). This suggests that similar processes are in operation, but with strong emission in the optical, unlike in the case of other known magnetars.

16.
J Vet Cardiol ; 55: 15-18, 2024 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-39059142

RESUMO

An 18-year-old female neutered Domestic Shorthair cat was referred for investigation of seizure-like episodes. Physical and neurological examination were unremarkable, as were systemic arterial blood pressure, cardiac troponin I, complete blood count and biochemistry profile. Diagnostic tests included transthoracic echocardiography which ruled out any structural cardiomyopathy, and electrocardiography which showed an underlying regular wide QRS-complex rhythm with pronounced shortening of the PR interval. Considering the findings, a diagnosis of suspected ventricular pre-excitation secondary to an accessory pathway was made. Further investigations were declined and, as no periods of tachycardia were seen on the five-minute electrocardiogram, no antiarrhythmic treatment was started.

17.
J Proteomics ; 304: 105232, 2024 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-38909954

RESUMO

Conjugated linoleic acid (CLA) is a group of natural isomers of the n-6 polyunsaturated fatty acid (PUFA) linoleic acid, exerting biological effects on cow physiology. This study assessed the impact of the mixture 50:50 (vol:vol) of CLA isomers (cis-9, trans-11 and trans-10, cis-12) on bovine peripheral blood mononuclear cells (PBMC) proteome, identifying 1608 quantifiable proteins. A supervised multivariate statistical analysis, sparse variant partial least squares - discriminant analysis (sPLS-DA) for paired data identified 407 discriminant proteins (DP), allowing the clustering between the CLA and controls. The ProteINSIDE workflow found that DP with higher abundance in the CLA group included proteins related to innate immune defenses (PLIN2, CD36, C3, C4, and AGP), with antiapoptotic (SERPINF2 and ITIH4) and antioxidant effects (HMOX1). These results demonstrated that CLA modulates the bovine PBMC proteome, supports the antiapoptotic and immunomodulatory effects observed in previous in vitro studies on bovine PBMC, and suggests a cytoprotective role against oxidative stress. SIGNIFICANCE: In this study, we report for the first time that the mixture 50:50 (vol:vol) of cis-9, trans-11, and trans-10, cis-12-CLA isomers modulates the bovine PBMC proteome. Our results support the immunomodulatory and antiapoptotic effects observed in bovine PBMC in vitro. In addition, the present study proposes a cytoprotective role of CLA mixture against oxidative stress. We suggest a molecular signature of CLA treatment based on combining a multivariate sparse discriminant analysis and a clustering method. This demonstrates the great value of sPLS-DA as an alternative option to identify discriminant proteins with relevant biological significance.


Assuntos
Leucócitos Mononucleares , Ácidos Linoleicos Conjugados , Proteoma , Animais , Bovinos , Ácidos Linoleicos Conjugados/farmacologia , Leucócitos Mononucleares/metabolismo , Leucócitos Mononucleares/efeitos dos fármacos , Proteoma/efeitos dos fármacos , Proteoma/metabolismo , Proteoma/análise
18.
Rev Sci Instrum ; 95(3)2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38445995

RESUMO

Knowledge about nonequilibrium dynamics in spin systems is of great importance to both fundamental science and technological applications. Inelastic neutron scattering (INS) is an indispensable tool to study spin excitations in complex magnetic materials. However, conventional INS spectrometers currently only perform steady-state measurements and probe averaged properties over many collision events between spin excitations in thermodynamic equilibrium, while the exact picture of re-equilibration of these excitations remains unknown. In this paper, we report on the design and implementation of a time-resolved laser-neutron pump-probe capability at hybrid spectrometer (beamline 14-B) at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory. This capability allows us to excite out-of-equilibrium magnons with a nanosecond pulsed laser source and probe the resulting dynamics using INS. Here, we discussed technical aspects to implement such a capability in a neutron beamline, including choices of suitable neutron instrumentation and material systems, laser excitation scheme, experimental configurations, and relevant firmware and software development to allow for time-synchronized pump-probe measurements. We demonstrated that the laser-induced nonequilibrium structure factor is able to be resolved by INS in a quantum magnet. The method developed in this work will provide SNS with advanced capabilities for performing out-of-equilibrium measurements, opening up an entirely new research direction to study out-of-equilibrium phenomena using neutrons.

19.
Opt Express ; 21 Suppl 6: A1028-34, 2013 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-24514923

RESUMO

The luminescence inverse method may be used to optically characterize a concentrator photovoltaic module. With this method, the module angular transmission is obtained by evaluating the light emission of a forward biased module. The influence of the emission of the cell when measuring the angular transmission is evaluated, and the process of building a global angular transmission from the set of individual optics-cell unit functions is explained. A case study of a module composed by several optics-cell units is presented. In order to validate the proposed measurement, results for five different CPV technologies are compared for both direct methods (i.e., solar simulator) and indirect methods (i.e., Luminescence inverse method).

20.
Hum Reprod ; 28(10): 2838-47, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23756703

RESUMO

STUDY QUESTION: Do patients with polycystic ovary syndrome (PCOS) have macroscopic and/or microscopic placental alterations? SUMMARY ANSWER: The placental structure in patients with PCOS, even in those with uncomplicated pregnancy, is altered. WHAT IS KNOWN ALREADY: The spectrum of pregnancy complications seems to have a common denominator: a defective trophoblast invasion and placentation. In women with PCOS, alterations in endovascular trophoblast invasion related to insulin resistance and hyperandrogenism have been observed. STUDY DESIGN, SIZE, DURATION: For this prospective case-control study, 30 pregnant patients with PCOS (cases) and 60 healthy pregnant women without PCOS features (controls) were enrolled and studied until delivery. Clinical, biochemical, ultrasonographic and obstetric data were recorded. The baseline clinical and biochemical data for screening for PCOS and for inclusion/exclusion were obtained before the seventh week of gestation. At delivery, placentas were collected and detailed macroscopic and microscopic analyses were performed. PARTICIPANTS, SETTING, METHODS: Cases and controls were matched for age and BMI (all <30 kg/m(2)). The matching procedure was one-to-two. Only subjects with spontaneous conception and uncomplicated pregnancies were included in the final analysis. MAIN RESULTS AND THE ROLE OF CHANCE: Placental weight (P = 0.04), thickness (P = 0.02), density (P = 0.02) and volume (P = 0.01) were significantly inferior in women with, compared with those without PCOS. The placentas from patients with PCOS more frequently had an irregular shape (P = 0.03) and a higher cord coiling index (P = 0.02). Differences between cases and controls also concerned the extent of villous (P = 0.04) and intervillous (P = 0.01) spaces, the extent of fibrosis (P = 0.03), endovascular trophoblast (depth, extension and morphometry) (P < 0.05) and mitotic activity (P = 0.01). The percentage of patients with lesions [22/30 (73.3%) versus 25/60 (41.7%), respectively; P = 0.01] and the mean number of placental lesions (3.5 ± 2.1 versus 1.4 ± 1.1, respectively; P = 0.02) were higher in the PCOS than the control group. The odds ratio for placental alterations, adjusted for weight gain, was 2.8 (95% confidence interval 1.3-9.9). LIMITATIONS, REASONS FOR CAUTION: The main limitation of the study was the selection of a specific PCOS sample, which is probably not representative of the PCOS phenotype as a whole. In fact, we excluded patients with PCOS who were obese and who achieved a pregnancy following the use of ovulation inductors or assisted reproduction techniques. WIDER IMPLICATIONS OF THE FINDINGS: The present study is the first to demonstrate that the morphology and microscopic structure of placenta in patients with PCOS with an uncomplicated pregnancy are altered. Further studies are needed to assess a correlation of these changes with the increased risk of obstetric complications observed in some pregnancies of women with PCOS. STUDY FUNDING/COMPETING INTEREST(S): The authors declare no conflict of interest and no financial support for the research. TRIAL REGISTRATION NUMBER: N/A.


Assuntos
Placenta/patologia , Síndrome do Ovário Policístico/patologia , Estudos de Casos e Controles , Feminino , Humanos , Placentação , Síndrome do Ovário Policístico/complicações , Síndrome do Ovário Policístico/diagnóstico por imagem , Gravidez , Complicações na Gravidez/diagnóstico por imagem , Complicações na Gravidez/patologia , Resultado da Gravidez , Ultrassonografia , Artéria Uterina/diagnóstico por imagem
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