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1.
J Assist Reprod Genet ; 41(2): 311-322, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38177974

RESUMO

Women undergoing controlled ovarian hyperstimulation prior to in vitro fertilization (IVF) are treated using various protocols to induce multiple follicular growths. Complete failure of all oocytes to mature during IVF cycles is rare; however, it is a known cause of primary female infertility. Recently, pathogenic variations in a few genes have been identified in women with oocyte maturation defects; however, the underlying genetic causes remain largely unknown.This study included a Turkish family comprising three sisters with recurring oocyte maturation arrest at the germinal vesicle stage after multiple ovarian stimulations. Exome sequencing revealed a homozygous missense variant (c.1037C>T, p.Ala346Val) in the EPAB gene (also known as PABPC1L) in all three affected sisters, which was either absent or heterozygous in the unaffected family members. Functional experiments confirming the pathogenicity of the variant were performed by transfecting HEK293T cells and demonstrated the instability and increased rate of proteolysis of the mutated PABPC1L/EPAB protein. The identified variant, located in the well-conserved fourth RNA recognition motif (RRM4), in silico 3D modelling suggested changes in the physical properties of the pathogenic variant of PABPC1L/EPAB. Our findings validate PABPC1L/EPAB as an essential genetic contributor to the oocyte maturation process in humans and have direct implications for the genetic counselling of patients and their family members.


Assuntos
Infertilidade Feminina , Feminino , Humanos , Núcleo Celular , Células HEK293 , Técnicas de Maturação in Vitro de Oócitos , Infertilidade Feminina/terapia , Oócitos/metabolismo , Oogênese/genética
2.
Entropy (Basel) ; 26(3)2024 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-38539766

RESUMO

It is argued that all physical knowledge ultimately stems from observation and that the simplest possible observation is that an event has happened at a certain space-time location X→=x→,t. Considering historic experiments, which have been groundbreaking in the evolution of our modern ideas of matter on the atomic, nuclear, and elementary particle scales, it is shown that such experiments produce as outputs streams of macroscopically observable events which accumulate in the course of time into spatio-temporal patterns of events whose forms allow decisions to be taken concerning conceivable alternatives of explanation. Working towards elucidating the physical and informational characteristics of those elementary observations, we show that these represent hugely amplified images of the initiating micro-events and that the resulting macro-images have a cognitive value of 1 bit and a physical value of Wobs=Eobsτobs≫h. In this latter equation, Eobs stands for the energy spent in turning the initiating micro-events into macroscopically observable events, τobs for the lifetimes during which the generated events remain macroscopically observable, and h for Planck's constant. The relative value Gobs=Wobs/h finally represents a measure of amplification that was gained in the observation process.

3.
Phys Rev Lett ; 130(15): 152502, 2023 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-37115897

RESUMO

We perform a systematic study of the α-particle excitation from its ground state 0_{1}^{+} to the 0_{2}^{+} resonance. The so-called monopole transition form factor is investigated via an electron scattering experiment in a broad Q^{2} range (from 0.5 to 5.0 fm^{-2}). The precision of the new data dramatically supersedes that of older sets of data, each covering only a portion of the Q^{2} range. The new data allow the determination of two coefficients in a low-momentum expansion, leading to a new puzzle. By confronting experiment to state-of-the-art theoretical calculations, we observe that modern nuclear forces, including those derived within chiral effective field theory that are well tested on a variety of observables, fail to reproduce the excitation of the α particle.

4.
Cereb Cortex ; 32(17): 3669-3689, 2022 08 22.
Artigo em Inglês | MEDLINE | ID: mdl-35059716

RESUMO

Fast synaptic communication uses diffusible transmitters whose spread is limited by uptake mechanisms. However, on the submicron-scale, the distance between two synapses, the extent of glutamate spread has so far remained difficult to measure. Here, we show that quantal glutamate release from individual hippocampal synapses activates extracellular iGluSnFr molecules at a distance of >1.5 µm. 2P-glutamate uncaging near spines further showed that alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-Rs and N-methyl-D-aspartate (NMDA)-Rs respond to distant uncaging spots at approximately 800 and 2000 nm, respectively, when releasing the amount of glutamate contained in approximately five synaptic vesicles. The uncaging-induced remote activation of AMPA-Rs was facilitated by blocking glutamate transporters but only modestly decreased by elevating the recording temperature. When mimicking release from neighboring synapses by three simultaneous uncaging spots in the microenvironment of a spine, AMPA-R-mediated responses increased supra-additively. Interfering with extracellular glutamate diffusion through a glutamate scavenger system weakly reduced field synaptic responses but not the quantal amplitude. Together, our data suggest that the neuropil is more permissive to short-range spread of transmitter than suggested by theory, that multivesicular release could regularly coactivate nearest neighbor synapses and that on this scale glutamate buffering by transporters primarily limits the spread of transmitter and allows for cooperative glutamate signaling in extracellular microdomains.


Assuntos
Ácido Glutâmico , Receptores de AMPA , Ácido Glutâmico/farmacologia , Hipocampo/fisiologia , Neurópilo/metabolismo , Receptores de AMPA/fisiologia , Receptores de N-Metil-D-Aspartato/metabolismo , Sinapses/fisiologia , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiônico/farmacologia
5.
BMC Health Serv Res ; 23(1): 386, 2023 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-37085862

RESUMO

BACKGROUND: With the development of next generation sequencing technologies in France, exome sequencing (ES) has recently emerged as an opportunity to improve the diagnosis rate of patients presenting an intellectual disability (ID). To help French policy makers determine an adequate tariff for ES, we aimed to assess the unit cost per ES diagnostic test for ID from the preparation of the pre-analytical step until the report writing step and to identify its main cost drivers. METHODS: A micro-costing bottom-up approach was conducted for the year 2018 in a French setting as part of the DISSEQ study, a cost-effectiveness study funded by the Ministry of Health and performed in collaboration with the GAD (Génétique des Anomalies du Développement), a genetic team from the Dijon University Hospital, and a public sequencing platform, the Centre National de Recherche en Génomique Humaine (CNRGH). The analysis was conducted from the point of view of these two ES stakeholders. All of the resources (labor, equipment, disposables and reagents, reusable material) required to analyze blood samples were identified, collected and valued. Several sensitivity analyses were performed. RESULTS: The unit nominal cost per ES diagnostic test for ID was estimated to be €2,019.39. Labor represented 50.7% of the total cost. The analytical step (from the preparation of libraries to the analysis of sequences) represented 88% of the total cost. Sensitivity analyses suggested that a simultaneous price decrease of 20% for the capture kit and 50% for the sequencing support kit led to an estimation of €1,769 per ES diagnostic test for ID. CONCLUSION: This is the first estimation of ES cost to be done in the French setting of ID diagnosis. The estimation is especially influenced by the price of equipment kits, but more generally by the organization of the centers involved in the different steps of the analysis and the time period in which the study was conducted. This information can now be used to define an adequate tariff and assess the efficiency of ES. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT03287206 on September 19, 2017.


Assuntos
Deficiência Intelectual , Humanos , Deficiência Intelectual/diagnóstico , Deficiência Intelectual/genética , Exoma , França
6.
Int J Audiol ; 62(12): 1176-1186, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36036176

RESUMO

OBJECTIVE: Subjective promontory stimulation is used to evaluate cochlear implant (CI) candidacy, but the test reliability is low. Electrically evoked auditory brainstem response (EABR) can verify the function of the auditory system objectively. This study's procedure uses a trans-tympanic rounded bent-tip electrode to perform pre-operative EABR under local anaesthesia (LA-TT-EABR) using MED-EL Software and Hardware. This study aimed to determine usability and effectiveness for CI candidates. DESIGN: We hypothesised that LA-TT-EABR waveforms of good quality would be related to successful hearing outcomes. We assumed that the duration of hearing loss/deafness was a confounding factor to study outcomes. STUDY SAMPLE: 19 borderline CI candidates. RESULTS: Positive LA-TT-EABR results were confirmed in 14 patients. LA-TT-EABR's mean latency was 2.05 ± 0.31 ms (eII/eIII) and 4.24 ± 0.39 ms (eIV/eV). Latencies weren't statistically different from intra-operative EABR elicited by basal CI contacts. All positive LA-TT-EABR patients benefitted from CI and speech performance improved one year after implantation. One patient with negative LA-TT-EABR was cochlear-implanted and had no hearing sensation. CONCLUSIONS: LA-TT-EABR is a tool in the frame of pre-operative objective testing the auditory pathway. It seems useful for clinical testing CI candidacy. Based on this study's outcomes, LA-TT-EABR should be recommended for uncertain CI candidates.


Assuntos
Implante Coclear , Implantes Cocleares , Humanos , Potenciais Evocados Auditivos do Tronco Encefálico/fisiologia , Anestesia Local , Vias Auditivas , Reprodutibilidade dos Testes , Limiar Auditivo/fisiologia
7.
Nanotechnology ; 34(10)2022 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-36399779

RESUMO

Vertical nanostructure technologies are becoming more important for the down scaling of nanoelectronic devices such as logic transistors or memories. Such devices require dense vertical nanostructured channel arrays (VNCA) that can be fabricated through a top-down approach based on group IV materials. We present progresses on the top-down fabrication of highly anisotropic and ultra-dense Si1-xGex(x= 0, 0.2, 0.5) VNCAs. Dense nanowire and nanosheet patterns were optimized through high resolution lithography and transferred onto Si1-xGexsubstrates by anisotropic reactive ion etching with a fluorine chemistry. The right gas mixtures for a given Ge content resulted in perfectly vertical and dense arrays. Finally we fabricated oxide shell/SiGe core heterostructures by dry- and wet-thermal oxidation and evaluated their applicability for nanostructure size engineering, as already established for silicon nanowires. The impact of the nanostructured shape (wire or sheet), size and Ge content on the oxide growth were investigated and analysed in detail through transmission electron microscopy.

8.
Eur J Nucl Med Mol Imaging ; 48(9): 2761-2770, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33537837

RESUMO

PURPOSE: One therapy option for prostate cancer patients with bone metastases is the use of [223Ra]RaCl2. The α-emitter 223Ra creates DNA damage tracks along α-particle trajectories (α-tracks) in exposed cells that can be revealed by immunofluorescent staining of γ-H2AX+53BP1 DNA double-strand break markers. We investigated the time- and absorbed dose-dependency of the number of α-tracks in peripheral blood mononuclear cells (PBMCs) of patients undergoing their first therapy with [223Ra]RaCl2. METHODS: Multiple blood samples from nine prostate cancer patients were collected before and after administration of [223Ra]RaCl2, up to 4 weeks after treatment. γ-H2AX- and 53BP1-positive α-tracks were microscopically quantified in isolated and immuno-stained PBMCs. RESULTS: The absorbed doses to the blood were less than 6 mGy up to 4 h after administration and maximally 16 mGy in total. Up to 4 h after administration, the α-track frequency was significantly increased relative to baseline and correlated with the absorbed dose to the blood in the dose range < 3 mGy. In most of the late samples (24 h - 4 weeks after administration), the α-track frequency remained elevated. CONCLUSION: The γ-H2AX+53BP1 assay is a potent method for detection of α-particle-induced DNA damages during treatment with or after accidental incorporation of radionuclides even at low absorbed doses. It may serve as a biomarker discriminating α- from ß-emitters based on damage geometry.


Assuntos
Leucócitos Mononucleares , Neoplasias da Próstata , Partículas alfa/efeitos adversos , Quebras de DNA de Cadeia Dupla , Dano ao DNA , Humanos , Masculino , Neoplasias da Próstata/radioterapia
9.
Eur Phys J A Hadron Nucl ; 57(1): 40, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33551676

RESUMO

A measurement of the double-polarization observable E for the reaction γ p → π 0 p is reported. The data were taken with the CBELSA/TAPS experiment at the ELSA facility in Bonn using the Bonn frozen-spin butanol (C 4 H 9 OH) target, which provided longitudinally-polarized protons. Circularly-polarized photons were produced via bremsstrahlung of longitudinally-polarized electrons. The data cover the photon energy range from E γ = 600 to 2310 MeV and nearly the complete angular range. The results are compared to and have been included in recent partial wave analyses.

10.
Nervenarzt ; 92(1): 1-8, 2021 Jan.
Artigo em Alemão | MEDLINE | ID: mdl-32394005

RESUMO

BACKGROUND: For the assessment of criminal responsibility in the context of sexual delinquency, the evaluation of the severity of a paraphilic disorder and the ability to be controlled are of particular importance. Established assessment criteria are insufficiently operationalized. AIM AND METHODS: The existing criteria were tested by experts of various professional groups with respect to the reliability. For this purpose, 14 experts assessed the criteria of 2 different sets of criteria based on 2 case vignettes (see electronic supplementary material). RESULTS AND CONCLUSION: The interrater reliability (IRR) with reference to the criteria of Briken and Müller was higher than the previously established criteria of Boetticher et al. The evaluation of the subjective importance of the criteria of both assessment scales showed that all criteria were rated as at least of average importance. It could thus be useful to initially include both sets of criteria for a greater transparency in the assessment process and to investigate this procedure in further studies.


Assuntos
Criminosos , Transtornos Parafílicos , Humanos , Transtornos Parafílicos/diagnóstico , Reprodutibilidade dos Testes
11.
Proc Biol Sci ; 287(1918): 20192228, 2020 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-31937224

RESUMO

Linking morphological differences in foraging adaptations to prey choice and feeding strategies has provided major evolutionary insights across taxa. Here, we combine behavioural and morphological approaches to explore and compare the role of the rostrum (bill) and micro-teeth in the feeding behaviour of sailfish (Istiophorus platypterus) and striped marlin (Kajikia audax) when attacking schooling sardine prey. Behavioural results from high-speed videos showed that sailfish and striped marlin both regularly made rostrum contact with prey but displayed distinct strategies. Marlin used high-speed dashes, breaking schools apart, often contacting prey incidentally or tapping at isolated prey with their rostra; while sailfish used their rostra more frequently and tended to use a slower, less disruptive approach with more horizontal rostral slashes on cohesive prey schools. Capture success per attack was similar between species, but striped marlin had higher capture rates per minute. The rostra of both species are covered with micro-teeth, and micro-CT imaging showed that species did not differ in average micro-tooth length, but sailfish had a higher density of micro-teeth on the dorsal and ventral sides of their rostra and a higher amount of micro-teeth regrowth, suggesting a greater amount of rostrum use is associated with more investment in micro-teeth. Our analysis shows that the rostra of billfish are used in distinct ways and we discuss our results in the broader context of relationships between morphological and behavioural feeding adaptations across species.


Assuntos
Perciformes/anatomia & histologia , Comportamento Predatório , Animais , Evolução Biológica , Comportamento Alimentar , Perciformes/fisiologia
12.
Phys Rev Lett ; 125(15): 152002, 2020 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-33095637

RESUMO

Data on the beam asymmetry Σ in the photoproduction of η mesons off protons are reported for tagged photon energies from 1130 to 1790 MeV (mass range from W=1748 MeV to W=2045 MeV). The data cover the full solid angle that allows for a precise moment analysis. For the first time, a strong cusp effect in a polarization observable has been observed that is an effect of a branch-point singularity at the pη^{'} threshold [E_{γ}=1447 MeV (W=1896 MeV)]. The latest BnGa partial wave analysis includes the new beam asymmetry data and yields a strong indication for the N(1895)1/2^{-} nucleon resonance, demonstrating the importance of including all singularities for a correct determination of partial waves and resonance parameters.

13.
Geophys Res Lett ; 47(11): e2020GL087978, 2020 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-32836515

RESUMO

Spaceborne NO2 column observations from two high-resolution instruments, Tropospheric Monitoring Instrument (TROPOMI) on board Sentinel-5 Precursor and Ozone Monitoring Instrument (OMI) on Aura, reveal unprecedented NO2 decreases over China, South Korea, western Europe, and the United States as a result of public health measures enforced to contain the coronavirus disease outbreak (Covid-19) in January-April 2020. The average NO2 column drop over all Chinese cities amounts to -40% relative to the same period in 2019 and reaches up to a factor of ~2 at heavily hit cities, for example, Wuhan, Jinan, while the decreases in western Europe and the United States are also significant (-20% to -38%). In contrast with this, although Iran is also strongly affected by the disease, the observations do not show evidence of lower emissions, reflecting more limited health measures.

14.
J Eur Acad Dermatol Venereol ; 34(2): 285-292, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31465594

RESUMO

BACKGROUND: In melanoma, preclinical data suggest a possible role of polyunsaturated fatty acids inhibiting cell growth. A new target molecule for free fatty acids, the G protein-coupled receptor GPR40, was identified in melanoma cells. OBJECTIVES: The aim of this study was to investigate GPR40 expression in human melanocytic tissues and to evaluate its potential as a prognostic marker. METHODS AND RESULTS: A total of 114 tissue sections of naevi, primary melanoma and melanoma metastasis were immunohistochemically stained with anti-GPR40. The staining was evaluated, using the immunoreactivity scoring system. Compared to naevi, primary melanoma and melanoma metastasis showed significantly higher levels of GPR40 (P < 0.05). In primary melanoma, GPR40 expression positively correlated with tumour thickness (P = 0.044) and AJCC level (P = 0.017) and in melanoma metastasis with AJCC level (P = 0.035). Primary melanoma patients with high levels of GPR40 had a significantly poorer overall survival (P = 0.004) and shorter disease-free survival (0.040). CONCLUSION: The present study identified GPR40 as a novel target molecule in melanoma. First evidence for a potential role of the receptor in tumour progression and metastases was found, and it could be demonstrated that GPR40 expression is negatively correlated with patient's survival.


Assuntos
Melanoma/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Neoplasias Cutâneas/metabolismo , Biomarcadores Tumorais/metabolismo , Feminino , Humanos , Masculino , Melanoma/patologia , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Neoplasias Cutâneas/patologia , Análise de Sobrevida
15.
Entropy (Basel) ; 22(4)2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-33286166

RESUMO

Making use of the equivalence between information and entropy, we have shown in a recent paper that particles moving with a kinetic energy ε carry potential information i p o t ( ε , T ) = 1 ln ( 2 ) ε k B   T relative to a heat reservoir of temperature T . In this paper we build on this result and consider in more detail the process of information gain in photon detection. Considering photons of energy E p h and a photo-ionization detector operated at a temperature T D , we evaluate the signal-to-noise ratio S N ( E p h , T D ) for different detector designs and detector operation conditions and show that the information gain realized upon detection, i r e a l ( E p h , T D ) , always remains smaller than the potential information i p o t ( E p h , T D ) carried with the photons themselves, i.e.,: i r e a l ( E p h , T D ) = 1 ln ( 2 ) ln ( S N ( E p h , T D ) ) ≤ i p o t ( E p h , T D ) = 1 ln ( 2 ) E p h k B T D   . This result is shown to be generally valid for all kinds of technical photon detectors, which shows that i p o t ( E p h , T D ) can indeed be regarded as an intrinsic information content that is carried with the photons themselves. Overall, our results suggest that photon detectors perform as thermodynamic engines that incompletely convert potential information into realized information with an efficiency that is limited by the second law of thermodynamics and the Landauer energy bounds on information gain and information erasure.

16.
Entropy (Basel) ; 22(7)2020 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-33286508

RESUMO

A thermodynamic approach to mechanical motion is presented, and it is shown that dissipation of energy is the key process through which mechanical motion becomes observable. By studying charged particles moving in conservative central force fields, it is shown that the process of radiation emission can be treated as a frictional process that withdraws mechanical energy from the moving particles and that dissipates the radiation energy in the environment. When the dissipation occurs inside natural (eye) or technical photon detectors, detection events are produced which form observational images of the underlying mechanical motion. As the individual events, in which radiation is emitted and detected, represent pieces of physical action that add onto the physical action associated with the mechanical motion itself, observation appears as a physical overhead that is burdened onto the mechanical motion. We show that such overheads are minimized by particles following Hamilton's equations of motion. In this way, trajectories with minimum curvature are selected and dissipative processes connected with their observation are minimized. The minimum action principles which lie at the heart of Hamilton's equations of motion thereby appear as principles of minimum energy dissipation and/or minimum information gain. Whereas these principles dominate the motion of single macroscopic particles, these principles become challenged in microscopic and intensely interacting multi-particle systems such as molecules moving inside macroscopic volumes of gas.

17.
BMC Cancer ; 19(1): 414, 2019 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-31046719

RESUMO

BACKGROUND: Chemotherapy-induced peripheral neuropathy (CIPN) can affect functional performance and quality of life considerably. Since balance training has proven to enhance physical function, it might be a promising strategy to manage CIPN-induced functional impairments. METHODS: Fifty cancer survivors with persisting CIPN after finishing their treatment were randomly allocated to an intervention (IG) or active control group (CG). The IG did endurance plus balance training, the CG only endurance training (twice weekly over 12 weeks). Pre- and post-assessments included functional performance, cardiorespiratory fitness, vibration sense, and self-reported CIPN symptoms (EORTC QLQ-CIPN20). RESULTS: Intention-to-treat analyses (n = 41) did not reveal a significant group difference (CG minus IG) for sway path in semi-tandem stance after intervention (primary endpoint), adjusted for baseline. However, our per-protocol analysis of 37 patients with training compliance ≥70% revealed: the IG reduced their sway path during semi-tandem stance (- 76 mm, 95% CI -141 - -17; CG: -6 mm, 95% CI -52 - 50), improved the duration standing on one leg on instable surface (11 s, 95% CI 8-17; CG: 0 s, 95%CI 0-5) and reported decreased motor symptoms (-8points, 95% CI -18 - 0; CG: -2points 95% CI -6 - 2). Both groups reported reduced overall- (IG: -10points, 95% CI -17 - -4; CG: -6points, 95% CI -11 - -1) and sensory symptoms (IG: -7points, 95% CI -15 - 0; CG: -7points, 95% CI -15 - 0), while only the CG exhibited objectively better vibration sense (knuckle: 0.8points, 95% CI 0.3-1.3; IG: 0.0points, 95% CI -1.1 - 0.9; patella: 1.0points, 95% CI 0.4-1.6: IG: -0.8points, 95% CI -0.2 - 0.0). Furthermore, maximum power output during cardiopulmonary exercise test increased in both groups (IG and CG: 0.1 W/kg, 95% CI 0.0-0.2), but only the CG improved their jump height (2 cm, 95% CI 0.5-3.5; IG: 1 cm, 95% CI -0.4 - 3.2). CONCLUSION: We suppose that endurance training induced a reduction in sensory symptoms in both groups, while balance training additionally improved patients' functional status. This additional functional effect might reflect the IG's superiority in the CIPN20 motor score. Both exercises provide a clear and relevant benefit for patients with CIPN. TRIAL REGISTRATION: German Clinical Trials Register (DRKS) number: DRKS00005419 , prospectively registered on November 19, 2013.


Assuntos
Antineoplásicos/efeitos adversos , Sobreviventes de Câncer/psicologia , Doenças do Sistema Nervoso Periférico/reabilitação , Adulto , Idoso , Idoso de 80 Anos ou mais , Aptidão Cardiorrespiratória , Tratamento Farmacológico , Treino Aeróbico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doenças do Sistema Nervoso Periférico/induzido quimicamente , Doenças do Sistema Nervoso Periférico/fisiopatologia , Doenças do Sistema Nervoso Periférico/psicologia , Qualidade de Vida , Resultado do Tratamento
18.
J Dairy Sci ; 102(7): 6431-6441, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31103292

RESUMO

The modern dairy industry is plagued by a high prevalence of claw horn lesions in cows, which cause lameness, affect well-being, limit milk production, and are responsible for premature removal of cows from the herd. The lateral hind claws are primarily affected, and this has been linked to a relatively higher load being exerted on the lateral claws when cows shift weight from one hind limb to the other. The vertical ground reaction forces and mean and maximum pressures under the claws were measured in 40 nonlame dairy cows before and during a shift in weight from one hind limb to the other, which was accomplished by applying pressure manually to one side of the pelvis. During square standing on firm ground, about two-thirds of the entire hind limb load was exerted on the 2 lateral claws, and the remaining one-third was exerted on the medial claws combined. At the moment of maximum weight shift, the lateral claw of the loaded limb bore almost two-thirds of the entire load of both hind limbs, with the heel zone bearing almost half of the load of both hind limbs. Subsequently, the load of the lateral claw of the contralateral hind limb decreased, as did the load of both medial claws. Thus, the weight redistribution had occurred predominantly between the lateral hind claws. The high load exerted on a lateral hind claw during weight shift and at maximum weight shift is assumed to play a role in the pathogenesis of claw horn lesions, particularly when accentuated by a softened claw horn and hard flooring.


Assuntos
Doenças dos Bovinos/fisiopatologia , Bovinos/crescimento & desenvolvimento , Doenças do Pé/veterinária , Membro Posterior/fisiopatologia , Casco e Garras/lesões , Coxeadura Animal/fisiopatologia , Animais , Peso Corporal , Bovinos/fisiologia , Feminino , Doenças do Pé/fisiopatologia , Marcha , Membro Posterior/lesões , Casco e Garras/fisiopatologia
19.
Phys Rev Lett ; 121(2): 022503, 2018 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-30085726

RESUMO

We report on the first Q^{2}-dependent measurement of the beam-normal single spin asymmetry A_{n} in the elastic scattering of 570 MeV vertically polarized electrons off ^{12}C. We cover the Q^{2} range between 0.02 and 0.05 GeV^{2}/c^{2} and determine A_{n} at four different Q^{2} values. The experimental results are compared to a theoretical calculation that relates A_{n} to the imaginary part of the two-photon exchange amplitude. The result emphasizes that the Q^{2} behavior of A_{n} given by the ratio of the Compton to charge form factors cannot be treated independently of the target nucleus.

20.
Phys Chem Chem Phys ; 20(28): 19087-19097, 2018 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-29974082

RESUMO

Capping ligands are vital in stabilizing various nanostructures and semiconductor quantum dots in which unusual optical properties, especially white light emission, have been realized. Oleic acid (OA) is a widely used capping ligand. Here, we report blue emission from OA in its free molecular form and further demonstrate this by anchoring OA over the surfaces of Al2O3, ZnAl2O4(ZA), ZnAl2O4:Eu3+ (ZA:Eu3+), and Y2O3:Eu3+. White light emission was observed from OA-modified ZA:Eu3+ nanophosphor due to mixing of broad blue emission of OA and red emission of Eu3+ through energy transfer from OA to Eu3+. A detailed study revealed the characteristic binding modes of OA and their dependence on Eu3+ concentration, structural inversion in ZA, and the optical properties and surface states in the pristine and OA-modified ZA:Eu3+. First principles density functional theory calculations were employed to provide an insight into the HOMO-LUMO levels of OA molecule and, electronic structure of pristine and OA-modified ZA surface. The binding of OA with the ZA:xEu3+ surface changes from bridging bidentate to chelating bidentate with increasing Eu3+ concentration in the lattice. The surface binding nature of the carboxylate group with the optimized surface of ZA and the creation of mid-gap states were deduced theoretically by using butanoic acid instead of OA. The blue emission from OA and its mixing with Eu3+ emission was further confirmed experimentally by anchoring it over Y2O3:Eu3+ red phosphor. These results show the multifunctional roles of OA as capping ligand, blue emitter and sensitizer in tuning the emission colour of red phosphors into white.

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