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1.
Phys Rev Lett ; 132(5): 056102, 2024 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-38364173

RESUMEN

The phonon dispersion of ice VII and that of its proton-ordered analog ice VIII are investigated through a combination of inelastic x-ray scattering (IXS) measurements and first-principles calculations of the oxygen sublattice dynamic structure factor. Particular attention is devoted to hydrogen-disorder in ice VII, addressed theoretically through a statistical ensemble of fictitious ordered supercell configurations. Similar phonon densities of states are found in both phases but are significantly less structured in the case of ice VII. Our data further show that, despite a full proton disorder, the acoustic phonon branches in this phase clearly inherit the periodicity of its body-centered cubic oxygen lattice. The calculations predict, however, the presence of gap openings in the one-atom phonon dispersion. These predictions are supported by revisiting the analysis of previous single-crystal IXS measurements along the longitudinal [111] branch of ice VII.

2.
J Chem Phys ; 160(15)2024 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-38634494

RESUMEN

Application of the coherent thermodynamic model [W. Holzapfel and S. Klotz, J. Chem. Phys. 155, 024506 (2021)] for H2O ice Ih to the more detailed data for D2O ice Ih provides better insight into the contributions from quenched proton disorder and offers a new basis for understanding the apparent differences between the data for thermal expansion measured with neutron diffraction on polycrystalline samples [A. Fortes, Acta Crystallogr., Sect. B: Struct. Sci., Cryst. Eng. Mater. 74, 196 (2018) and A. Fortes, Phys. Chem. Chem. Phys 21, 8264 (2019)] and macroscopic dilatation measurements on single crystals [D. Buckingham et al., Phys. Rev. Lett. 121, 185505 (2018)]. The comparison points to contributions from defects effecting the two techniques in different ways. The uncertainties in thermodynamic data due to the contributions from proton disorder and additional defects are compared with the "reference data" [R. Feistel and W. Wagner, J. Phys. Chem. Ref. Data 35, 1021 (2006)] for H2O ice Ih.

3.
Phys Rev Lett ; 125(19): 195501, 2020 Nov 06.
Artículo en Inglés | MEDLINE | ID: mdl-33216588

RESUMEN

The phase diagram and melting curve of water ice is investigated up to 45 GPa and 1600 K by synchrotron x-ray diffraction in the resistively and laser heated diamond anvil cell. Our melting data evidence a triple point at 14.6 GPa, 850 K. The latter is shown to be related to a first-order solid transition from the dynamically disordered form of ice VII, denoted ice VII^{'}, toward a high-temperature phase with the same bcc oxygen lattice but larger volume and higher entropy. Our experiments are compared to ab initio molecular dynamics simulations, enabling us to identify the high-temperature bcc phase with the predicted superionic ice VII^{''} phase [J.-A. Hernandez and R. Caracas, Phys. Rev. Lett. 117, 135503 (2016).PRLTAO0031-900710.1103/PhysRevLett.117.135503].

4.
Eur J Neurol ; 27(10): 1856-1866, 2020 10.
Artículo en Inglés | MEDLINE | ID: mdl-32402145

RESUMEN

BACKGROUND AND PURPOSE: Argyrophilic grain disease (AGD) is a limbic-predominant 4R-tauopathy. AGD is thought to be an age-related disorder and is frequently detected as a concomitant pathology with other neurodegenerative conditions. There is a paucity of data on the clinical phenotype of pure AGD. In elderly patients, however, AGD pathology frequently associates with cognitive decline, personality changes, urine incontinence and cachexia. In this study, clinicopathological findings were analysed in individuals younger than 75. METHODS: Patients were identified retrospectively based on neuropathological examinations during 2006-2017 and selected when AGD was the primary and dominant pathological finding. Clinical data were obtained retrospectively through medical records. RESULTS: In all, 55 patients (2% of all examinations performed during that period) with AGD were identified. In seven cases (13%) AGD was the primary neuropathological diagnosis without significant concomitant pathologies. Two patients were female, median age at the time of death was 64 years (range 51-74) and the median duration of disease was 3 months (range 0.5-36). The most frequent symptoms were progressive cognitive decline, urinary incontinence, seizures and psychiatric symptoms. Brain magnetic resonance imaging revealed mild temporal atrophy. CONCLUSIONS: Argyrophilic grain disease is a rarely recognized limbic tauopathy in younger individuals. Widening the clinicopathological spectrum of tauopathies may allow identification of further patients who could benefit from tau-based therapeutic strategies.


Asunto(s)
Enfermedades Neurodegenerativas , Tauopatías , Anciano , Atrofia/patología , Encéfalo/patología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Tauopatías/complicaciones , Tauopatías/epidemiología , Proteínas tau/metabolismo
5.
Herz ; 43(1): 26-33, 2018 Feb.
Artículo en Alemán | MEDLINE | ID: mdl-29147971

RESUMEN

At the end of August 2017 the European Society of Cardiology (ESC) and the European Association for Cardio-Thoracic Surgery (EACTS) published new joint guidelines for the treatment of valvular heart disease. These guidelines incorporate the scientific progress since the last version of the guidelines published in 2012. This article reviews current guideline recommendations for antiplatelet and anticoagulative therapy after surgical/interventional treatment of the aortic and mitral valves and discusses the underlying scientific evidence.


Asunto(s)
Anticoagulantes/uso terapéutico , Válvula Aórtica/cirugía , Enfermedades de las Válvulas Cardíacas/cirugía , Implantación de Prótesis de Válvulas Cardíacas , Válvula Mitral/cirugía , Inhibidores de Agregación Plaquetaria/uso terapéutico , Administración Oral , Anticoagulantes/efectos adversos , Relación Dosis-Respuesta a Droga , Estudios de Seguimiento , Guías como Asunto , Hemorragia/inducido químicamente , Humanos , Inhibidores de Agregación Plaquetaria/efectos adversos , Ensayos Clínicos Controlados Aleatorios como Asunto , Factores de Riesgo , Tromboembolia/prevención & control
6.
Schmerz ; 32(3): 188-194, 2018 06.
Artículo en Alemán | MEDLINE | ID: mdl-29693198

RESUMEN

BACKGROUND: The chronic pelvic pain syndrome (CPPS) can be associated with physiotherapeutic findings. An interprofessional approach is recommended for patients with CPPS; however, no standardized physiotherapeutic assessment and documentation instrument for specific physiotherapeutic assessments exist, which is not only the foundation for physiotherapy but also for interprofessional communication. OBJECTIVE: The aim was the development of a physiotherapeutic assessment instrument for patients with CPPS and therefore, to create a tool for clinical use, research and interprofessional communication. MATERIAL AND METHODS: Based on an explorative literature search and an expert consensus, the first version of the instrument was developed as part of a specialized outpatient clinic. This version was applied clinically for 13 months, edited and finalized after another expert consensus. RESULTS: The developed instrument Physical Therapy Assessment for Chronic Pelvic Pain Syndrome (PTA-CPPS) lists external and internal groups of muscles for a systematic assessment of myofascial findings. Functional capacity, breathing movements as well as scars and regions of pain are recorded. A manual for the assessment protocol was developed as accompanying material. CONCLUSION: The developed instrument provides for the first time a physiotherapeutic assessment tool for patients with CPPS for interprofessional clinical and scientific use.


Asunto(s)
Dolor Crónico , Dolor Pélvico , Prostatitis , Humanos , Masculino , Síndrome
7.
Phys Rev Lett ; 119(24): 245701, 2017 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-29286747

RESUMEN

Despite the simplicity of its molecular unit, water is a challenging system because of its uniquely rich polymorphism and predicted but yet unconfirmed features. Introducing a novel space of generalized coordinates that capture changes in the topology of the interatomic network, we are able to systematically track transitions among liquid, amorphous, and crystalline forms throughout the whole phase diagram of water, including the nucleation of crystals above and below the melting point. Our approach, based on molecular dynamics and enhanced sampling or free energy calculation techniques, is not specific to water and could be applied to very different structural phase transitions, paving the way towards the prediction of kinetic routes connecting polymorphic structures in a range of materials.

8.
Phys Chem Chem Phys ; 19(3): 1875-1883, 2017 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-28009862

RESUMEN

We probe the possible inclusion of salt (NaCl) in the ice VII lattice over the pressure range from 2 to 4 gigapascal. We combine data from neutron diffraction experiments under pressure and from computational structure searches based on density functional theory. We observe that the high density amorphous precursor (NaCl·10.2D2O) crystallises during annealing at high pressure in the vicinity of the phase boundary between pure ices VII and VIII. The structure formed is very similar to that of pure ice VII. Our simulations indicate that substituting water molecules in the ice VII lattice with Na+ and Cl- ions would lead to a significant expansion of the lattice parameter. Since this expansion was not observed in our experiments, the ice crystallised is likely to be pure D2O or contains only a small fraction of the ions from the salt solution.

9.
Phys Chem Chem Phys ; 17(21): 14054-63, 2015 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-25955540

RESUMEN

The structure of amorphous NaCl solutions produced by fast quenching is studied as a function of pressure, up to 4 GPa, by combined neutron diffraction experiments and classical molecular dynamics simulations. Similarly to LiCl solutions the system amorphizes at ambient pressure in a dense phase structurally similar to the e-HDA phase in pure water. The measurement of the static structure factor as a function of pressure allowed us to validate a new polarizable force field developed by Tazi et al., 2012, never tested under non-ambient conditions. We infer from simulations that the hydration shells of Na(+) cations form well defined octahedra composed of both H2O molecules and Cl(-) anions at low pressure. These octahedra are gradually broken by the seventh neighbour moving into the shell of first neighbours yielding an irregular geometry. In contrast to LiCl solutions and pure water, the system does not show a polyamorphic transition under pressure. This confirms that the existence of polyamorphism relies on the tetrahedral structure of water molecules, which is broken here.

10.
J Med Entomol ; 52(4): 719-21, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-26335480

RESUMEN

The kissing bugs--Triatoma rubida (Uhler), Triatoma protracta (Uhler), and Triatoma recurva (Stal)--are common hematophagous bugs in southeastern Arizona and responsible for severe allergic reactions in some individuals who are bitten. They also possess the potential to transmit the blood parasite, Trypanosoma cruzi. We previously found the essential oil, citronella, to be an excellent deterrent of feeding of T. rubida on a restrained mouse. In this work, we tested major components--alcohols, aldehydes, and monoterpenes--of citronella oil for repellency against the three common triatome species endemic in southern Arizona. The following citronella oil components--geraniol, citronellol, limonene, and citronellal--in different concentrations and combinations were tested. All components of citronella oil demonstrated some inhibition of feeding, ranging from very weak inhibition (limonene) to significant inhibition (geraniol and citronellol). A mixture of geraniol and citronellol was found to be repellant at concentrations of .165 and .165 vol%, respectively, for all three triatome species. Citronellal and limonene had no significant repellent activity. The repellent activity of citronella oil appears to be acting through direct contact with the bugs rather than diffusion of vapors.


Asunto(s)
Repelentes de Insectos/farmacología , Insectos Vectores/efectos de los fármacos , Aceites de Plantas/farmacología , Triatoma/efectos de los fármacos , Monoterpenos Acíclicos , Animales , Control de Insectos/métodos , Repelentes de Insectos/química , Monoterpenos/química , Monoterpenos/farmacología , Aceites de Plantas/química , Terpenos/química , Terpenos/farmacología
11.
J Chem Phys ; 142(12): 124503, 2015 Mar 28.
Artículo en Inglés | MEDLINE | ID: mdl-25833592

RESUMEN

Urea, like many network forming compounds, has long been known to form inclusion (guest-host) compounds. Unlike other network formers like water, urea is not known to form such inclusion compounds with simple molecules like hydrogen. Such compounds if they existed would be of interest both for the fundamental insight they provide into molecular bonding and as potential gas storage systems. Urea has been proposed as a potential hydrogen storage material [T. A. Strobel et al., Chem. Phys. Lett. 478, 97 (2009)]. Here, we report the results of high-pressure neutron diffraction studies of urea and D2 mixtures that indicate no inclusion compound forms up to 3.7 GPa.

12.
J Appl Microbiol ; 116(6): 1427-37, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24905215

RESUMEN

AIMS: To investigate and compare the bactericidal activity (BA) of active bromine and chlorine compounds in the absence and presence of protein load. METHODS AND RESULTS: Quantitative killing tests against Escherichia coli and Staphylococcus aureus were performed both in the absence and in the presence of peptone with pairs of isosteric active chlorine and bromine compounds: hypochlorous and hypobromous acid (HOCl and HOBr), dichloro- and dibromoisocyanuric acid, chlorantine and bromantine (1,3-dibromo- and 1,3 dichloro-5,5-dimethylhydantoine), chloramine T and bromamine T (N-chloro- and N-bromo-4-methylbenzenesulphonamide sodium), and N-chloro- and N-bromotaurine sodium. To classify the bactericidal activities on a quantitative basis, an empirical coefficient named specific bactericidal activity (SBA), founded on the parameters of killing curves, was defined: SBA= mean log reductions/(mean exposure times x concentration) [mmol 1(-1) min (-1)]. In the absence of peptone, tests with washed micro-organisms revealed a throughout higher BA of bromine compounds with only slight differences between single substances. This was in contrast to chlorine compounds, whose killing times differed by a factor of more than four decimal powers. As a consequence, also the isosteric pairs showed according differences. In the presence of peptone, however, bromine compounds showed an increased loss of BA, which partly caused a reversal of efficacy within isosteric pairs. CONCLUSIONS: In medical practice, weakly oxidizing active chlorine compounds like chloramines have the highest potential as topical anti-infectives in the presence of proteinaceous material (mucous membranes, open wounds). Active bromine compounds, on the other hand, have their chance at insensitive body regions with low organic matter, for example skin surfaces. SIGNIFICANCE AND IMPACT OF THE STUDY: The expected protein load is one of the most important parameters for selection of a suited active halogen compound.


Asunto(s)
Antiinfecciosos Locales/farmacología , Compuestos de Bromina/farmacología , Compuestos de Cloro/farmacología , Peptonas/química , Bromatos/farmacología , Cloraminas/farmacología , Escherichia coli/efectos de los fármacos , Ácido Hipocloroso/farmacología , Staphylococcus aureus/efectos de los fármacos , Taurina/análogos & derivados , Taurina/farmacología , Compuestos de Tosilo/farmacología , Triazinas/farmacología
13.
Phys Rev Lett ; 110(17): 173004, 2013 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-23679720

RESUMEN

High pressure viscosity and dielectric measurements were carried out on two monohydroxy alcohols, 2-ethyl-1-hexanol and 5-methyl-2-hexanol, at room temperature. Analysis of the dielectric relaxation times versus viscosity revealed the breakdown of the Einstein-Debye relation above some characteristic pressure. The failure of the Einstein-Debye relation is a manifestation of pressure induced changes of supramolecular hydrogen bonded structures which occur in these liquids.

14.
Phys Rev Lett ; 111(18): 185901, 2013 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-24237539

RESUMEN

First measurements of the self-dynamics of liquid water in the GPa range are reported. The GPa range has here become accessible through a new setup for the Paris-Edinburgh press specially conceived for quasielastic neutron scattering studies. A direct measurement of both the translational and rotational diffusion coefficients of water along the 400 K isotherm up to 3 GPa, corresponding to the melting point of ice VII, is provided and compared with molecular dynamics simulations. The translational diffusion is observed to strongly decrease with pressure, though its variation slows down for pressures higher than 1 GPa and decouples from that of the shear viscosity. The rotational diffusion turns out to be insensitive to pressure. Through comparison with structural data and molecular dynamics simulations, we show that this is a consequence of the rigidity of the first neighbors shell and of the invariance of the number of hydrogen bonds of a water molecule under high pressure. These results show the inadequacy of the Stokes-Einstein-Debye equations to predict the self-diffusive behavior of water at high temperature and high pressure, and challenge the usual description of hot dense water behaving as a simple liquid.

15.
J Med Entomol ; 50(3): 664-7, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23802464

RESUMEN

The kissing bug, Triatoma rubida (Uhler) is a common hematophagous bug in Tucson, AZ, and is responsible for causing severe allergic reactions in some bitten individuals. DEET, picaridin, tea tree oil, peppermint oil, and citronella oil were tested for repellency to T. rubida and its ability to probe and feed on a small restrained rat. No long range repellency was observed with any of the test materials. The lowest repellent concentrations observed were: 10% DEET, 7% picaridin; 30% tea tree oil, 3.3% peppermint oil, and 0.165% citronella oil. Only citronella oil was able to stop all probing and feeding by T. rubida. Citronella oil appears to be a promising potential repellent to prevent sleeping people from being bitten by kissing bugs.


Asunto(s)
DEET/farmacología , Repelentes de Insectos/farmacología , Aceites Volátiles/farmacología , Piperidinas/farmacología , Triatoma/efectos de los fármacos , Animales , Relación Dosis-Respuesta a Droga , Mentha piperita , Aceites de Plantas/farmacología , Aceite de Árbol de Té/farmacología , Triatoma/fisiología
16.
J Phys Chem Lett ; 14(9): 2301-2307, 2023 Mar 09.
Artículo en Inglés | MEDLINE | ID: mdl-36847363

RESUMEN

Solid mixtures of ammonia and water, the so-called ammonia hydrates, are thought to be major components of solar and extra-solar icy planets. We present here a thorough characterization of the recently reported high pressure (P)-temperature (T) phase VII of ammonia monohydrate (AMH) using Raman spectroscopy, X-ray diffraction, and quasi-elastic neutron scattering (QENS) experiments in the ranges 4-10 GPa, 450-600 K. Our results show that AMH-VII exhibits common structural features with the disordered ionico-molecular alloy (DIMA) phase, stable above 7.5 GPa at 300 K: both present a substitutional disorder of water and ammonia over the sites of a body-centered cubic lattice and are partially ionic. The two phases however markedly differ in their hydrogen dynamics, and QENS measurements show that AMH-VII is characterized by free molecular rotations around the lattice positions which are quenched in the DIMA phase. AMH-VII is thus a peculiar crystalline solid in that it combines three types of disorder: substitutional, compositional, and rotational.

17.
Phys Rev Lett ; 106(12): 125701, 2011 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-21517327

RESUMEN

We investigated the metastable phase diagram of an ionic salt aqueous solution, LiCl:6D2O, at high pressure and low temperature by neutron diffraction measurements and computer simulations. We show that the presence of salt triggers a stepwise transformation, under annealing at high pressure, to a new very high-density amorphous form. The transition occurs abruptly at 120 K and 2 GPa, is reversible, and is characterized by a sizeable enthalpy release. Simulations suggest that the polyamorphic transition is linked to a local structural reorganization of water molecules around the Li ions.

18.
Phys Rev Lett ; 104(11): 115501, 2010 Mar 19.
Artículo en Inglés | MEDLINE | ID: mdl-20366482

RESUMEN

Oxygen is the only elemental molecule which carries an electronic magnetic moment. As a consequence, the different solid phases encountered on cooling show various degrees of magnetic order, and similar behavior is expected under compression. Here we present neutron diffraction data which reveal the magnetic ordering under high pressure in the delta ("orange") phase, i.e., in the range 6-8 GPa and 20-240 K. We show that delta-O2 contains in total three different magnetic structures, all of them being antiferromagnetic and differing in the stacking sequence of O2 sheets along the c axis. This structural diversity can be explained by the quasi-two-dimensional nature of delta-O2 and the strong orientation dependence of the magnetic exchange interaction between O2 molecules. The results show that delta-O2 is a room temperature antiferromagnet.

19.
Thorac Cardiovasc Surg ; 58 Suppl 2: S189-93, 2010 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-20101538

RESUMEN

The German Disease Management Guideline "Chronic Heart Failure" intends to guide physicians working in the field of diagnosis and treatment of heart failure. The guideline provides a tool on the background of evidence based medicine. The following short review wants to give insights into the role of some surgical treatment options to improve heart failure, such as revascularization, ventricular reconstruction and aneurysmectomy, mitral valve reconstruction, ventricular assist devices and heart transplantation.


Asunto(s)
Insuficiencia Cardíaca/cirugía , Guías de Práctica Clínica como Asunto , Medicina Basada en la Evidencia , Femenino , Alemania , Humanos , Masculino , Resultado del Tratamiento
20.
Thorac Cardiovasc Surg ; 58 Suppl 2: S194-7, 2010 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-20101539

RESUMEN

The Eurotransplant International Foundation in Leiden, the Netherlands, is responsible for mediation and allocation of organ donation procedures to its member countries Austria, Belgium, Croatia, Germany, Luxembourg, the Netherlands and Slovenia. To provide organs for the patients who require urgent transplantation, the "high urgent (HU)" status was introduced in 2001 in Germany . This new HU allocation system is applicable to neonates as well as adults. However, waiting times on HU status exceed several weeks to months. Therefore an increasing number of pediatric patients has to undergo implantation of a ventricular assist device (VAD). In the present report we discuss the current Eurotransplant heart allocation system for pediatric heart transplantation in the light of a neonate with 452 days on mechanical support. We compare the average waiting time of patients on HU status at our center and their outcome in 2007 and 2008 (Data obtained from Eurotransplant International Foundation). Waiting time on HU status in our center increased significantly from 2007 to 2008. Therefore more patients require VAD support as bridging to transplantation. The case of a neonate under long-term VAD support is an outstanding example of the negative effects of this development.


Asunto(s)
Corazón Auxiliar , Femenino , Trasplante de Corazón , Humanos , Recién Nacido , Masculino , Factores de Tiempo , Listas de Espera
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