Phase Engineering via Aluminum Doping Enhances the Electrochemical Stability of Lithium-Rich Cobalt-Free Layered Oxides for Lithium-Ion Batteries.

Lithium-rich, cobalt-free oxides are promising potential positive electrode materials for lithium-ion batteries because of their high energy density, lower cost, and reduced environmental and ethical concerns. However, their commercial breakthrough is hindered because of their subpar electrochemical stability. This work studies the effect of aluminum doping on Li1.26 Ni0.15 Mn0.61 O2 as a lithium-rich, cobalt-free layered oxide. Al doping suppresses voltage fade and improves the capacity retention from 46% for Li1.26 Ni0.15 Mn0.61 O2 to 67% for Li1.26 Ni0.15 Mn0.56 Al0.05 O2 after 250 cycles at 0.2 C. The undoped material has a monoclinic Li2 MnO3 -type structure with spinel on the particle edges. In contrast, Al-doped materials (Li1.26 Ni0.15 Mn0.61-x Alx O2 ) consist of a more stable rhombohedral phase at the particle edges, with a monoclinic phase core. For this core-shell structure, the formation of Mn3+ is suppressed along with the material's decomposition to a disordered spinel, and the amount of the rhombohedral phase content increases during galvanostatic cycling. Whereas previous studies generally provided qualitative insight into the degradation mechanisms during electrochemical cycling, this work provides quantitative information on the stabilizing effect of the rhombohedral shell in the doped sample. As such, this study provides fundamental insight into the mechanisms through which Al doping increases the electrochemical stability of lithium-rich cobalt-free layered oxides.

Health risk assessment of gaseous elemental mercury (GEM) in Mexico City.

Emissions of gaseous elemental mercury (GEM or Hg0) from different sources in urban areas are important subjects for environmental investigations. In this study, atmospheric Hg measurements were conducted to investigate air pollution in the urban environment by carrying out several mobile surveys in Mexico City. This work presents atmospheric concentrations of GEM in terms of diurnal variation trends and comparisons with criteria for pollutant concentrations such as CO, SO2, NO2, PM2.5, and PM10. The concentration of GEM was measured during the pre-rainy period by using a high-resolution active air sampler, the Lumex RA 915 M mercury analyzer. In comparison with those for other cities worldwide, the GEM concentrations were similar or slightly elevated, and they ranged from 0.20 to 30.23 ng m-3. However, the GEM concentration was significantly lower than those in contaminated areas, such as fluorescent lamp factory locations and gold mining zones. The GEM concentrations recorded in Mexico City did not exceed the WHO atmospheric limit of 200 ng m-3. We performed statistical correlation analysis which suggests equivalent sources between Hg and other atmospheric pollutants, mainly NO2 and SO2, emitted from urban combustion and industrial plants. The atmospheric Hg emissions are basically controlled by sunlight radiation, as well as having a direct relationship with meteorological parameters. The area of the city studied herein is characterized by high traffic density, cement production, and municipal solid waste (MSW) treatment, which constantly release GEM into the atmosphere. In this study, we included the simulation with the HYSPLIT dispersion model from three potential areas of GEM release. Emissions from industrial corridors and volcanic plumes localized outside the urban area contribute to the pollution of Mexico City and mainly affect the northern area during specific periods and climate conditions. Using the USEPA model, we assessed the human health risk resulting from exposure to inhaled GEM among residents of Mexico City. The results of the health risk assessment indicated no significant noncarcinogenic risk (hazard quotient (HQ) < 1) or consequent adverse effects for children and adults living in the sampling area over the study period. GEM emissions inventory data is necessary to improve our knowledge about the Hg contribution and effect in urban megacity areas with the objective to develop public safe policy and implementing the Minamata Convention.

Xanthogranulomatous Pyelonephritis and Its Differential Diagnoses: An In-Depth Case Review.

Xanthogranulomatous pyelonephritis is a rare chronic infectious process of the kidney, which has been described in three different forms: diffuse, segmental, and focal. It is also known as the great simulator since its clinical, radiological, and histopathological manifestations tend to be confused with other entities. We describe a case of a 55-year-old male patient with two months of clinical manifestations characterized by a 7x7-cm palpable mass in his right lumbar region, which was hot and painful upon touch and increasing in size. This article aims to present a case of xanthogranulomatous pyelonephritis and compare it with its primary differential diagnoses. It is evident that despite the condition being considered a simulating pathology, some key differences can be found to identify and distinguish it.

Gaseous Elemental Mercury (GEM) in the Mexico City Metropolitan Area.

This paper presents atmospheric gaseous elemental mercury (GEM) data recorded during two short-term monitoring surveys in the Mexico City Metropolitan Area (MCMA) at 12th May 2019 and at 22nd May 2020, during conditions of low and high human activity respectively. Results, although they are limited, can be considered as the representative range of exposure to GEM of the inhabitants of MCMA; differences in results reveal the impact of human activities on GEM background levels (2.53 and 3.76 ng m-3, respectively). GEM concentrations and their spatial distribution does not allow for the identification of important industrial sources and do not reach intervention pollution levels. The activity of the Popocatépetl volcano is not likely to have an effect on GEM in the MCMA. In spite the evident decrease in GEM concentrations compared with data previously reported, monitoring must be carried out routinely given Mexico's participation in the Minamata Convention on Mercury.

Imaging Nanometer Phase Coexistence at Defects During the Insulator-Metal Phase Transformation in VO2 Thin Films by Resonant Soft X-ray Holography.

We use resonant soft X-ray holography to image the insulator-metal phase transition in vanadium dioxide with element and polarization specificity and nanometer spatial resolution. We observe that nanoscale inhomogeneity in the film results in spatial-dependent transition pathways between the insulating and metallic states. Additional nanoscale phases form in the vicinity of defects which are not apparent in the initial or final states of the system, which would be missed in area-integrated X-ray absorption measurements. These intermediate phases are vital to understand the phase transition in VO2, and our results demonstrate how resonant imaging can be used to understand the electronic properties of phase-separated correlated materials obtained by X-ray absorption.

Evolución de las cajas de polyetheretherketone (PEEK). Estudio clínico y radiológico / Évolution des cages en polyétheréthercétone (PEEK). Étude clinique et radiologique / Evolution of polyetheretherketone (PEEK) boxes. Clinical and radiological study

Introducción: las cajas cervicales son implantes desarrollados como una alternativa a la utilización del injerto óseo estructural para la fusión cervical anterior. El objetivo de este estudio fue analizar la clínica y los resultados radiológicos en una serie de pacientes sometidos a disectomía y descompresión cervical anterior, a los que se les implantó una caja PEEK. Método: estudio retrospectivo, descriptivo, longitudinal de una serie de 78 pacientes incluidos en el estudio desde el año 2007 al 2013. El control radiológico incluyó radiografía anteroposterior y lateral. El seguimiento clínico y radiológico de los pacientes se llevó a cabo desde los 3 meses hasta los 12 meses. Resultados: 65 pacientes tuvieron una evolución clínica favorable (83,3 por ciento) y la evolución radiológica confirmó que 66 pacientes (84,6 por ciento) tenían una buena colocación del injerto, sin lesiones en espacios adyacentes con una fusión correcta. Conclusiones: hasta la fecha hay pocos estudios descriptivos sobre el implante de las cajas PEEK, los resultados mostrados en este trabajo están acordes a los publicados con anterioridad en este mismo campo, lo que da validez al trabajo presentado. Este estudio confirma los buenos resultados clínicos y radiológicos de pacientes a los que se les implantó una caja PEEK; se muestra su eficacia en la discectomía cervical anterior y artrodesis(AU)

Introduction: Cervical cases are implants developed as an alternative to the use of structural bone graft for anterior cervical fusion. The objective of this study was to analyze the clinical and radiological results in a series of patients submitted to anterior cervical dissectomy and decompression, to whom a PEEK box was implanted. Method: A retrospective, descriptive, longitudinal study was conducted in a series of 78 patients included in the study from 2007 to 2013. Radiological control included anteroposterior and lateral radiographies. Clinical and radiological follow-up of these patients was carried out from 3 months to 12 months. Results: 65 patients had a favorable clinical course (83.3 percent) and the radiological evolution confirmed that 66 patients (84.6 percent) had a good placement of the graft without lesions in adjacent spaces with a correct fusion. Conclusions: To date there are few descriptive studies on the implantation of PEEK boxes. This paper results are in line with those published previously in this same field, which legitimate the presented work. This study confirms the good clinical and radiological results in patients who were implanted with a PEEK box; its effectiveness in anterior cervical discectomy and arthrodesis is shown(AU)

Introduction: Les cages cervicales sont des implants développés comme alternative de la greffe osseuse structurelle pour la fusion cervicale antérieure. Le but de cette étude est d'analyser la technique et les résultats radiologiques dans une série de patients traités par discectomie et décompression cervicale antérieure, et implantation d'une cage PEEK. Méthodes: Étude rétrospective, descriptive et longitudinale d'une série de 78 patients inclus dans une étude depuis l'année 2007 jusqu'à l'année 2013. L'étude radiologique a compris des clichés en position antéro-postérieure et latérale. Le suivi clinique et radiologique des patients a pris de 3 à 12 mois. Résultats: L'évolution clinique a été satisfaisante chez 65 patients (83,3 pourcent), tandis que l'étude radiologique a confirmé que le greffon était bien placé, il n'y avait pas de lésions dans les espaces adjacentes, et la fusion était correcte chez 66 patients (84,6 pourcent). Conclusions: Jusqu'à maintenant, il y a peu d'études descriptives abordant l'implantation des cages PEEK. Le présent travail est validé, car ses résultats sont en concordance avec les travaux publiés auparavant dans ce domaine. Cette étude confirme les bons résultats obtenus chez les patients ayant subi l'implantation d'une cage PEEK ; son efficacité est démontrée dans la discectomie cervicale antérieure et l'arthrodèse(AU)

Clorhidrato de bacampicilina en el tratamiento de infecciones agudas de las vias aereas inferiores. / Bacampicillin chlorhydrate in the treatment of lower respiratory tract infections

Se trataron 40 pacientes que sufrian diferentes padecimientos de las vias aereas inferiores,con 1200 mg diarios de bacampicilina, por periodos de 7 a 12 dias. Se obtuvo la cura clinica en 33 casos y mejoria importante en los 7 restantes; la cura bacteriologica se obtuvo en 34 de los 40 casos. No se presentaron efectos secundarios