Sluggish anion transport provides good kinetic stability to the anhydrous anti-perovskite solid electrolyte Li3OCl.

Some lithium oxyhalides have been proposed as low-cost solid electrolytes for having room-temperature Li+ conductivity close to commercial liquid electrolytes, but with the advantages of enabling higher energy densities through the use of the Li metal anode and not being flammable. However, the stability of anhydrous anti-perovskite lithium oxyhalides, such as Li3OCl, is not well understood yet: whereas theoretical calculations show they should decompose into lithium halides and Li2O (except at high temperatures), there is no experimental evidence of such decomposition. Thus, here we use a combination of analytical calculations and force-field-based atomistic modelling to investigate the role of kinetics in the stability of anhydrous Li3OCl. The results show that due to sluggish Cl- and O2- transport this material has good kinetic stability below ∼400 K under high concentration gradients, below ∼450 K under typical cell voltages, and at all temperatures against local composition fluctuations. Furthermore, the good kinetic stability explains the apparent discrepancy between theoretical thermodynamics calculations and experimental observations and contributes to enlighten the nature and extent of this material's stability. The methods presented here can also be extended to other battery materials that are predicted to decompose, to access the safe temperature range they can undergo without degrading.

Relación entre probabilidad clínica de síndrome del túnel del carpo y estudios neurofisiológicos / Relationship between clinical probability of carpal tunnel syndrome and neurophysiological studies

Objetivos. Determinar la sensibilidad y la especificidad de los rasgos clínicos y los factores sociodemográficos en el síndrome del túnel carpiano (STC) y proponer una medida para estimar la probabilidad clínica de presentar la enfermedad.Material y método. Se realizó un estudio prospectivo, descriptivo y transversal de 100 pacientes referidos para evaluación neurofisiológica de STC, divididos cronológicamente en dos grupos de 50 casos (93 y 90 manossintomáticas, respectivamente). También fueron estudiados30 sujetos sanos (60 manos asintomáticas). A todos se lesrealizó interrogatorio y examen físico, orientados al diagnóstico de STC, y estudios de conducción nerviosa periférica comparativos del nervio mediano; se determinó el índice sensorial combinado (ISC), el cual se utilizó como criterio de referencia para conocer la eficacia diagnóstica de los rasgos clínicos en el primer grupo de pacientes y en el grupo control.Resultados. Se identificaron como factores sociodemo- gráficos significativos: sexo femenino, tiempo de evolución de 6 meses o superior y afectación bilateral. Los rasgos clínicos de adormecimiento, dolor, parestesias nocturnas, localización de éstos en el territorio del nervio mediano, debilidadmuscular, maniobra de Phalen o signo de Tinel positivos estuvieron significativamente asociados con alteraciones neurofisiológicas. A partir de estos resultados se propone la estimación de la probabilidad clínica anterior a la prueba diagnóstica (PAP). Un análisis de regresión lineal, efectuado en el segundo grupo de pacientes, mostró una asociación significativa entre PAP e ISC (F[1,148] = 49,7; p < 0,000).Conclusiones. La PAP puede considerarse de utilidad comomedida resumen de la presencia de rasgos clínicos significativos en el STC

Purpose. To determine the sensitivity and specificity of a series of clinical features and risk factors in carpal tunnel syndrome (CTS) and suggest a diagnostic measure to clinically estimate probability of disease.Materials and methods. A prospective, cross-sectional study was performed of 100 patients consecutively referred to us for a neurophysiological evaluation of CTS. Patients were chronologically divided into two groups of 50 cases each (93 and 90 symptomatic hands respectively). Evaluation procedures included a clinical interview and physical examination to test for the classic signs of CTS, as well as comparative sensory peripheral median nerve conduction studies. The combined sensory index (CSI) was also determined and used as a reference tool to calculate the sensitivityand specificity of clinical features in the first group of patients and in the control group.Results. Female gender, bilateral involvement and persistence of symptoms for 6 months or more were identified as risk factors. The pattern of critical clinical features associated with electrophysiological damage included numbness, nocturnal paresthesia and pain, symptoms in areas innervated by the median nerve, muscular weakness, positive Phalen maneuver or a positive Tinel’s sign. On the basis of theseresults, we suggest a clinical model for estimating clinical probability prior to the electrophysiological test (PAT). A linear regression analysis found a significant association between PAT and CSI in the second group of patients (F[1.148] = 49.7; p < 0.000).Conclusion. PAT can be considered useful as diagnostic measure of the clinical features of CTS (AU)

Effect of intermittent convection movements on voltammogram and current transients.

The influence of intermittent convection movements on electrochemical voltammograms is investigated. When the bath temperature rises to 315 K, the voltammograms exhibit irregular plateaus that differ for independent voltammetry scans, even when the setup is maintained under exactly the same conditions. In this paper, we show that such behavior can be caused by convection movements that develop in the electrolytic cell as a consequence of velocity fluctuations, since no bubbles or regular convective patterns are observed at this temperature. Theoretical current-potential curves for the heterogeneous deposition of metals on silicon electrodes is derived from a model consisting of a one-dimensional balance equation that includes diffusion, convection, and reaction through a time-dependent boundary condition. We obtain the current density associated with the adsorption of particles on the surface and, through this expression, we consider the effect of constant convective velocities on voltammograms. Finally, we examine the effect of random convective movements, described by a Monte Carlo algorithm that takes into account the random temporal fluctuations around a null convective current. The model predicts accentuated fluctuations on the current profiles, especially on the current plateaus that correspond to a stationary current regime. The validity of the theoretical model is checked against experimental data.

Evolución electrofisiológica del síndrome del túnel del carpo / Evolutive electrophysiological modifications of carpal tunnel syndrome

Objetivos. Describir las modificaciones evolutivas electrofisiológicas en el síndrome del túnel del carpo (STC). Material y métodos. Se realizó un estudio transversal y descriptivo en 183 manos sintomáticas de 100 pacientes con diagnóstico clínico de STC, remitidos para evaluación electrofisiológica (17 a 72 años de edad, el 90 % del sexo femenino), que fueron divididas en tres grupos de acuerdo al tiempo de evolución: inferior a 6 meses, entre 6 meses y un año, superior a un año. A todos se les realizaron estudios electrofisiológicos del nervio mediano, de tipo motor, mixto y sensitivo, que fueron clasificados como normales, con afectación ligera, moderada y grave. Resultados. Un análisis de varianza mostró resultados electrofisiológicos significativamente peores en los pacientes con más de un año de evolución: latencia mediano motor distal (F = 3,69, p < 0,02), latencia mediano mixto con estimulación palmar a 8 cm (F = 4,91, p < 0,009), velocidad de conducción sensitiva de tercer dedo a muñeca (F = 4,12, p < 0,01). La mayoría de los casos con resultados electrofisiológicos negativos se encontraron en el período de 6 a 12 meses, mientras que el grupo con afectación grave predominó en aquellos pacientes con más de un año de evolución. Discusión. En el STC ocurre empeoramiento electrofisiológico progresivo, con alteraciones sensitivas y motoras evidentes en aquellos pacientes con un año o más de evolución. La existencia de procesos de desmielinización local y remielinización crónica pudieran ser una posible explicación para la elevada proporción de estudios electrofisiológicos normales con alteraciones sensitivas ligeras observados en el grupo con tiempo de evolución entre 6 y 12 meses

Objective. To describe electrophysiological modifications in carpal tunnel syndrome (CTS). Material and methods. A cross-sectional and descriptive study that studied 183 symptomatic hands of 100 patients with CTS clinical diagnosis (17 to 72 years old; 90 % females; mean symptoms duration time, 19 ± 21 months), was performed. These hands were divided into three groups according to duration of symptoms: less than 6 months, from 6 months to 12 months, more than 12 months. Electrophysiological studies of the motor, mixed and sensory median nerve were performed. These were classified as having normal, mild, moderate and severe damage. Results. An analysis of variance showed significantly worse electrophysiological abnormalities in patients with evolution time superior to 12 months: motor median distal latency (F = 3.69, p < 0.02), mixed median palm latency (F = 4.91, p < 0.009), sensory conduction velocity in the segment third digit to wrist (F = 4.12, p < 0.01). The period between 6 to 12 months showed the greatest proportion of negative nerve conduction studies while the group with severe disease was predominate in those patients with more than one year's evolution. Discussion. Progressive electrophysiological worsening occurs in CTS, with clear sensory and motor alterations in those patients with one or more years of evolution. The existence of local demyelination and chronic remyelination may be a possible explanation for the elevated proportion of normal electrophysiological studies with mild sensory alterations observed in the group with an evolution time between 6 to 12 months

Indication of unusual pentagonal structures in atomic-size Cu nanowires.

We present a study of the structural and quantum conductance properties of atomic-size copper nanowires generated by mechanical stretching. The atomistic evolution was derived from time-resolved electron microscopy observations and molecular dynamics simulations. We have analyzed the quantum transport behavior by means of conductance measurements and theoretical calculations. The results suggest the formation of an unusual and highly stable pentagonal Cu nanowire with a diameter of approximately 0.45 nm and approximately 4.5 conductance quanta.

Phenotypes of lung mononuclear phagocytes in HIV seronegative tuberculosis patients: evidence for new recruitment and cell activation.

Mycobacterium tuberculosis preferentially resides in mononuclear phagocytes. The mechanisms by which mononuclear phagocytes keep M. tuberculosis in check or by which the microbe evades control to cause disease remain poorly understood. As an initial effort to delineate these mechanisms, we examined by immunostaining the phenotype of mononuclear phagocytes obtained from lungs of patients with active tuberculosis. From August 1994 to March 1995, consecutive patients who had an abnormal chest X-ray, no demonstrable acid-fast bacilli in sputum specimens and required a diagnostic bronchoalveolar lavage (BAL) were enrolled. Of the 39 patients enrolled, 21 had microbiologically diagnosed tuberculosis. Thirteen of the 21 tuberculosis patients were either HIV seronegative (n = 12) or had no risk factor for HIV and constituted the tuberculosis group. For comparison, M. tuberculosis negative patients who had BAL samples taken during this time (n = 9) or normal healthy volunteers (n = 3) served as control group. Compared to the control group, the tuberculosis group had significantly higher proportion of cells expressing markers of young monocytes (UCHM1) and RFD7, a marker for phagocytic cells, and increased expression of HLA-DR, a marker of cell activation. In addition, tuberculosis group had significantly higher proportion of cells expressing dendritic cell marker (RFD1) and epithelioid cell marker (RFD9). These data suggest that despite recruitment of monocytes probably from the peripheral blood and local cell activation, host defense of the resident lung cells is insufficient to control M. tuberculosis.