Fully textured monolithic perovskite/silicon tandem solar cells with 25.2% power conversion efficiency.

Tandem devices combining perovskite and silicon solar cells are promising candidates to achieve power conversion efficiencies above 30% at reasonable costs. State-of-the-art monolithic two-terminal perovskite/silicon tandem devices have so far featured silicon bottom cells that are polished on their front side to be compatible with the perovskite fabrication process. This concession leads to higher potential production costs, higher reflection losses and non-ideal light trapping. To tackle this issue, we developed a top cell deposition process that achieves the conformal growth of multiple compounds with controlled optoelectronic properties directly on the micrometre-sized pyramids of textured monocrystalline silicon. Tandem devices featuring a silicon heterojunction cell and a nanocrystalline silicon recombination junction demonstrate a certified steady-state efficiency of 25.2%. Our optical design yields a current density of 19.5 mA cm-2 thanks to the silicon pyramidal texture and suggests a path for the realization of 30% monolithic perovskite/silicon tandem devices.

Rear textured p-type high temperature passivating contacts and their implementation in perovskite/silicon tandem cells.

Silicon solar cells based on high temperature passivating contacts are becoming mainstream in the photovoltaic industry. Here, we developed a high-quality boron-doped poly-silicon hole contact. When combined with a co-processed phosphorus-doped poly-silicon electron contact, high-voltage silicon bottom cells could be demonstrated and included in 28.25%-efficient perovskite/Si tandems. The active area was 4 cm2 active area and the front electrode was screen-printed.

Tick-associated diseases identified from hunting dogs during the COVID-19 pandemic in a Mayan community in Yucatan, Mexico.

Background: Hunting activity in the Mayan communities has increased due to COVID-19 and domestic dogs have gained more importance. Due to their proximity to humans, domestic dogs are a bridge between tick-borne diseases (TBDs) and humans and their peri-domestic environment. In Mexico, and especially in rural regions, there were not adequate records of TBDs during the SARS-CoV-2 pandemic. Aim: Identify TBD of ticks collected during the COVID-19 pandemic in a rural community. Methods: Tick capture was carried out in March 2021, in Teabo, Yucatan. Ticks were removed using from domestic dogs and placed in ethanol. Collected ticks were morphologically identified and underwent DNA extraction and a partial segment of the mitochondrial 16S-rDNA gene was amplified to corroborate the tick species. The DNA was screened for the presence of Anaplasma spp., Borrelia spp., Ehrlichia spp., and Rickettsia spp. Purified amplification products were submitted for sequencing and the results were compared to those deposited in GenBank using BLAST. Results: We collected 33 ectoparasites, Ixodes affinis, Rhipicephalus sanguineus, Rhipicephalus microplus, and Amblyomma mixtum on 11 hunting dogs. The most frequent ectoparasite was R. sanguineus (66%). We detected the presence of DNA of Rickettsia endosymbiont in I. affinis and Anaplasma platys in R. sanguineus. Rickettsia endosymbiont presented a similarity of 100% with the partial sequence of R. endosymbiont of I. affinis isolate IACACTM001 16S ribosomal RNA gene and the sequence of A. platys had a similarity of 100% with the partial sequence of the isolate 23-33TX 16S ribosomal RNA gene of A. platys from dogs from Texas, USA and with the partial sequence of the isolate L134 16S ribosomal RNA gene of Ehrlichia canis from dogs from Piura, Peru. Conclusion: We confirmed for the first time the presence of A. platys in R. sanguineus and R. endosymbiont in I. affinis ticks from dogs in the state of Yucatan.

Thermal Analysis of Parylene Thin Films for Barrier Layer Applications.

Biocompatible polymer films demonstrating excellent thermal stability are highly desirable for high-temperature (>250 °C) applications, especially in the bioelectronic encapsulation domain. Parylene, as an organic thin film, is a well-established polymer material exhibiting excellent barrier properties and is often the material of choice for biomedical applications. This work investigated the thermal impact on the bulk properties of four types of parylene films: parylene N, C, VT4, and AF4. The films, deposited using the standard Gorham process, were analyzed at varying annealing temperatures from room temperature up to 450 °C. Thermal properties were identified by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) methods, while X-ray diffraction (XRD) analysis showed the effect of high-temperature exposure on the structural properties. In addition to thermal and structural analysis, the barrier properties were measured through the helium transmission rate (HTR) and the water vapor transmission rate (WVTR). Fluorinated parylene films were confirmed to be exceptional materials for high-temperature applications. Parylene AF4 film, 25um thick, demonstrated excellent barrier performance after 300 °C exposure, with an HTR and a WVTR of 12.18 × 103 cm3 (STP) m−2 day−1 atm−1 and 6.6 g m−2 day−1, respectively.

Pediatric Healthcare Needs and Barriers Self-Reported by a Rural Hispanic Community.

Purpose Hispanic immigrants in rural communities can be a hard-to-reach population with many unmet medical needs that have yet to be properly identified. This is particularly true for rural immigrant children. This study focused on documenting self-reported healthcare barriers among this isolated population to identify methods for reducing health disparities among this vulnerable population. Methods Participants at recurrent mobile health fairs were anonymously surveyed from June 2016 to January 2018. Differences between the US and foreign-born Hispanic participants were investigated in bivariate analyses. Findings We received 35 completed surveys. The majority (79.3%) of participants reported household incomes below the federal poverty line for a family of four. Only 4.5% of foreign-born children were insured, compared with 77% of US-born children (p<0.001). Greater than 85% of foreign-born and 100% of US-born children were fully vaccinated, but half of the participants were seeking preventative care. Most patients identified insurance and cost as the most significant barriers to healthcare. Conclusions Access to insurance was the largest barrier identified by this population, with a significant difference between foreign and US-born children. This gap is further compounded by many responders living below the federal poverty line, limiting their ability to pay for the growing costs of uninsured treatment. This study also indicates this Hispanic community's prioritized desire for access to preventative healthcare and high uptake of childhood immunizations.

Fatal murine typhus with hemophagocytic lymphohistiocytosis in a child.

Hemophagocytic lymphohistiocytosis is a rare complication in Rickettsia typhi infections. We report the case of a 2-year-old boy with sudden night-onset fever, pallor, neck adenopathy and erythematous macular rash on the thorax, thighs and buttocks. During admission, he developed hyponatremia, hypoalbuminemia, anemia, thrombocytopenia, leukopenia, neutropenia, liver damage, hemorrhages and persistent fever. No hematological improvement was observed after the initial management, neoplastic diseases were discarded by bone marrow aspiration and lymph node biopsy; hemophagocytic lymphohistiocytosis was diagnosed. By immunohistochemistry and indirect immunofluorescence, murine typhus was also diagnosed and doxycycline was started with transitory recovery. Later, the child developed kidney failure and distributive shock that evolved to cardiac arrest and death. This is the first case report in Mexico on a fatal murine typhus associated with hemophagocytic lymphohistiocytosis in which the etiology was evidenced by histopathology.

Surgical management of Aspergillus colonization associated with lung hydatid disease.

Colonization with Aspergillus sp. usually occurs in previously formed lung cavities. Cystectomy is a widely used surgical technique for hydatid lung disease that can also leave residual cavities and potentially result in aspergilloma. We present two cases of this rare entity and a case with Aspergillus sp. colonization of an existing ruptured hydatid cyst.

Severe mitral regurgitation and hepatopulmonary hydatid cysts: what should be treated first?

Hydatid cyst can simultaneously affect the liver and lung. Some patients might have additional comorbidities that can make management more challenging. Here, we present a 10-year-old boy with hepatopulmonary hydatid cysts and severe mitral regurgitation, who was successfully managed with a staged surgical approach treating the lung first, followed by the liver and finally, the heart.

Silver Film Surface Modification by Ion Bombardment Decreases Surface Plasmon Resonance Absorption.

Silver thin films covered with dielectric films serving as protective coatings are desired for telescope mirrors, but durable coatings have proved elusive. As part of an effort to develop long-lived protected-silver mirrors, silver thin films were deposited by electron beam evaporation using a physical vapor deposition system at the University of California Observatories Astronomical Coatings Lab. The silver films were later covered with a stack of dielectric films utilizing silicon nitride and titanium dioxide deposited by ion-assisted electron beam evaporation to fabricate protected mirrors. In-situ argon ion bombardment was introduced after silver deposition and prior to the deposition of dielectric films to assess its effects on the performance of the mirrors. We found that ion bombardment of the silver influenced surface morphology and reflectivity, and these effects correlated with time between silver deposition and ion bombardment. The overall reflectivity at wavelengths in the range of 350-800 nm was found to improve due to ion bombardment, which was qualitatively interpreted as a result of decreased surface plasmon resonance coupling. We suggest that the observed decrease in coupling is caused by silver grain boundary pinning due to ion bombardment suppressing silver surface diffusion, forming smoother silver-dielectric interfaces.

Design Parameters for Subwavelength Transparent Conductive Nanolattices.

Recent advancements with the directed assembly of block copolymers have enabled the fabrication over cm2 areas of highly ordered metal nanowire meshes, or nanolattices, which are of significant interest as transparent electrodes. Compared to randomly dispersed metal nanowire networks that have long been considered the most promising next-generation transparent electrode material, such ordered nanolattices represent a new design paradigm that is yet to be optimized. Here, through optical and electrical simulations, we explore the potential design parameters for such nanolattices as transparent conductive electrodes, elucidating relationships between the nanowire dimensions, defects, and the nanolattices' conductivity and transmissivity. We find that having an ordered nanowire network significantly decreases the length of nanowires required to attain both high transmissivity and high conductivity, and we quantify the network's tolerance to defects in relation to other design constraints. Furthermore, we explore how both optical and electrical anisotropy can be introduced to such nanolattices, opening an even broader materials design space and possible set of applications.

Reflectometry-Ellipsometry Reveals Thickness, Growth Rate, and Phase Composition in Oxidation of Copper.

The oxidation of copper is a complicated process. Copper oxide develops two stable phases at room temperature and standard pressure (RTSP): cuprous oxide (Cu2O) and cupric oxide (CuO). Both phases have different optical and electrical characteristics that make them interesting for applications such as solar cells or resistive switching devices. For a given application, it is necessary to selectively control oxide thickness and cupric/cuprous oxide phase volume fraction. The thickness and composition of a copper oxide film growing on the surface of copper widely depend on the characteristics of as-deposited copper. In this Research Article, two samples, copper films prepared by two different deposition techniques, electron-beam evaporation and sputtering, were studied. As the core part of the study, the formation of the oxidized copper was analyzed routinely over a period of 253 days using spectroscopic polarized reflectometry-spectroscopic ellipsometry (RE). An effective medium approximation (EMA) model was used to fit the RE data. The RE measurements were complemented and validated by using X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and X-ray diffraction (XRD). Our results show that the two samples oxidized under identical laboratory ambient conditions (RTSP, 87% average relative humidity) developed unique oxide films following an inverse-logarithmic growth rate with thickness and composition different from each other over time. Discussion is focused on the ability of RE to simultaneously extract thickness (i.e., growth rate) and composition of copper oxide films and on plausible physical mechanisms responsible for unique oxidation habits observed in the two copper samples. It appears that extended surface characteristics (i.e., surface roughness and grain boundaries) and preferential crystalline orientation of as-deposited polycrystalline copper films control the growth kinetics of the copper oxide film. Analysis based on a noncontact and nondestructive measurement, such as RE, to extract key material parameters is beneficial for conveniently understanding the oxidation process that would ultimately enable copper oxide-based devices at manufacturing scales.

Epizootic cutaneous pythiosis in beef calves.

Enzootic bovine granulomatosis (EBG) is a disease that affects beef calves in the flooded Savanna regions of Venezuela. Although Pythium insidiosum was originally the suspected etiologic agent, nothing was done to demonstrate its presence in the infected animals. The objective of this study was to investigate the etiologic agent causing cutaneous lesions in a group of 63 calves diagnosed with EBG. The collected samples were analyzed by histopathology, immunohistochemistry, serology, and mycological techniques. The clinical manifestations of BEG included ulcerated and swollen granulomatous lesions on the limbs of young calves. Histopathological studies revealed an eosinophilic inflammatory reaction with neutrophils, giant cells and branching hyphae with the Splendore-Hoeppli phenomenon. Immunofluorescence analysis identified the branching hyphae as elements of the fungal-like organism P. insidiosum. Wet mounts in 10% KOH revealed hyaline slender branching hyaline coenocytic hyphae, but cultures from those samples were negative. Anti-P. insidiosum immunoglobulins were also demonstrated in the collected sera of the affected bovines using latex agglutination, immunodiffusion, ELISA, and Western Blot. The histopathological, immunohistochemical, and serological tests showed for the first time that P. insidiosum could be involved in epizootic bovine pythiosis.

Aortoesophageal fistula as a late complication of type B aortic dissection.

We present a patient with aortoesophageal fistula that occurred years after an acute type B aortic dissection that was treated medically. This patient developed aneurysmal dilatation of the chronically dissected aorta, which finally eroded into the esophagus. Endovascular management with the placement of a stent graft was performed, but the patient ultimately died of multiorgan failure and possible myocardial infarction.

Mecanismos de resistencia antifúngica de los azoles en Candida albicans. Una revisión / Mechanisms of antifungal resistance of azoles in Candida albicans. A review

Resumen Candida albicans es una levadura comensal capaz de causar una infección oportunista en hospederos susceptibles denominada candidiasis. El tratamiento para combatir la candidiasis puede ser tópico o sistémico según el tipo de infección, los antifúngicos más utilizados son los derivados imidazólicos (fluconazol, itraconazol, ketoconazol, miconazol etc.), sin embargo en la actualidad se observa una disminución en la efectividad de estos medicamentos, es decir, un fenómeno de resistencia de parte del microorganismo a estos fármacos, esto debido principalmente, al surgimiento de levaduras resistentes, a la aparición de nuevas especies patógenas, a la prescripción irracional de antimicóticos como profilaxis y al aumento de las dosis terapéuticas. Existen dos mecanismos por los que Candida puede adquirir resistencia a un azol. El primero es por mutaciones moleculares de la enzima diana del antifúngico, como la alteración de las enzimas relacionadas en la síntesis del ergosterol y el segundo por la alteración en las bombas de expulsión: ATP-binding cassette (ABC) y facilitadores mayores (MF). En este trabajo se resumen los principales mecanismos de resistencia en Candida y la importancia de hacer pruebas de susceptibilidad con el fin de brindar un tratamiento adecuado para este tipo de infecciones oportunistas.

Abstract Candida albicans is a commensal yeast capable of causing an opportunistic infection called candidiasis in susceptible hosts. Treatment to combat Candida may be topical or systemic according to the type of infection and the imidazole derivatives (fluconazole, itraconazole, ketoconazole, miconazole, etc.) are the antifungals most widely used. However, resistance to these drugs is observed by a decrement in their effectiveness. This is mainly due to the emergence of resistant yeasts and of new pathogenic species, as well as to the irrational prescribing of antifungal prophylaxis and the use of higher therapeutic doses. There are two mechanisms by which Candida can acquire an azole resistance, the first is by molecular mutations of antifungal target enzyme, as the alteration of enzymes related to the synthesis of ergosterols and the second by change in the efflux pumps, such as those of ATP-binding cassette and the higher facilitators. In this work the main mechanisms of resistance to Candida and the importance of performing susceptibility tests in order to provide an adequate treatment for this type of opportunistic infections are summarized.

Infección por Sporothrix schenckii en agricultores del caserío "Peñón de Gabante": Municipio Tovar. Estado Aragua. Venezuela / Infection caused by Sporothrix schenckii in farmers from the village "Peñón de Gabante": Tovar municipality. Aragua state. Venezuela

In Aragua state (Venezuela) there are farming communities such as the Tovar municipality that meet geographical and climatic conditions favourable for the development of the fungus Sporothrix schenckii, in which farmer workers would be particularly exposed and at risk of infection and development of sporotrichosis. Accordingly, it was determined the prevalence of this infection in 148 farmers of both sexes from the village "Peñón de Gabante" through the intradermoreaction to esporotrichin. The overall prevalence was 24% and the frequency of infection increased with the age of the farmers, the time working as farmers and it was higher in men (27.6%) than in women (20.8%), reaching values of 39.1% in persons of 50 years and older and 28% in those with more than 10 years occupied in agriculture, although it was independent of these variables. Also, it was found a lower percentage of intradermal positivity (21.8%) in farmers that reported regular use of protective equipment in compare to those whom used it irregularly (27.9%) even though the differences weren't statistically significant. Statistically significant association (p< 0.005) was found between the clinical signs referred by farmers and the intradermopositivity to the esporotrichin, direct contact with plants with thorny branches and/or fruits of prickly shell (p< 0.001) and direct contact with the soil during the process of preparation, fertilization and sowing the crops (p<0.005). These findings suggest that the studied area is endemic to Sporothrix schenckii and farmers found in occupational risk of acquiring this infection.

En el estado Aragua, Venezuela, existen comunidades agrícolas como las del municipio Tovar, que reúnen condiciones geográficas y climáticas favorables para el desarrollo del hongo Sporothrix schenckii, en las que los agricultores estarían particularmente expuestos y a riesgo de adquirir la infección y desarrollar esporotricosis. En conse cuencia, se determinó la prevalencia de esta infección en 148 agricultores de ambos sexos del caserío "Peñón de Gabante", mediante la intradermorreacción a la esporotriquina. La prevalencia fue 24% y la frecuencia de infección incrementó con la edad de los agricultores, el tiempo desarrollando esta labor y fue mayor en hombres (27,6%) que en mujeres (20,8%), alcanzando valores de 39,1% en las personas con edades de 50 años o más y de 28% en aquellos con más de 10 años laborando en la agricultura, aunque resultó independiente de estas variables. Se halló un menor porcentaje de positividad (21,8%) en los agricultores que utilizan en forma regular equipos de protección en comparación con aquellos que lo hacen irregularmente (27,9%), aunque las diferencias no fueron estadísticamente significativas. Se encontró asociación estadísticamente significativa entre la intradermopositividad a la esporotriquina y los signos clínicos relacionados a la esporotricosis (p< 0,005), el contacto directo tanto con plantas de ramas espinosas y/o frutos de cáscara espinosa (p< 0,001) y con el contacto directo con la tierra durante el proceso de preparación, abono y/o siembra de sus cultivos (p< 0,005). Estos hallazgos sugieren que la zona estudiada es endémica para Sporothrix schenckii y los agricultores se encuentran en riesgo ocupacional de contraer esta infección.

Percutaneous endovascular management of occluded HeRO dialysis access device.

The Hemodialysis Reliable Outflow (HeRO) device is a novel alternative for dialysis access in patients with no suitable veins in the upper extremities. We placed a HeRO device in a 67-year-old woman with end-stage renal disease and 2 months later, it was being used for hemodialysis. After 1 month of uneventful use, the device thrombosed and it was rescued with a percutaneous endovascular approach. The device remains patent 6 months after the intervention.

Staged approach for surgical management of external iliac vein aneurysm associated with traumatic femoral arteriovenous fistula.

Aneurysms of the iliac vein are rare. They can occur in association with arteriovenous fistulae located elsewhere. Here, we present a 30-year-old man who developed a large left external iliac vein aneurysm in association with a chronic traumatic arteriovenous fistula in the left thigh. Less than 25 cases of iliac vein aneurysms have been reported in the last 40 years. The presentation and treatment of this condition has been heterogeneous. We suggest that adequate surgical treatment can be offered in a staged approach: aneurysm resection with reconstruction should be done first, followed by closure of the arteriovenous fistula 6 months later.

Total anomalous pulmonary venous return and Mayer-Rokitansky-Kuster-Hauser syndrome.

We present an adult woman with total anomalous pulmonary venous return (TAPVR) and Mayer-Rokitansky-Kuster-Hauser syndrome that was diagnosed intraoperatively during a planned atrial secundum defect closure. Surgical repair of TAPVR was performed with good outcome.

Pythiosis: Una patología emergente en Venezuela / Pythiosis: An emergent pathology in Venezuela

La pythiosis es una enfermedad que se presenta en humanos y en otros mamíferos, tales como equinos, caninos y bovinos. El agente etiológico de esta patología es Pythium insidiosum, un oomycete acuático presente en diversas regiones geográficas del mundo. Las manifestaciones clínicas cutáneas de tipo granulomatoso y gastrointestinales son las presentaciones que predominan en animales infectados. La infección puede diseminarse hacia otros tejidos (ej., óseo y pulmonar). La pythiosis humana tiene cuatro formas clínicas de presentación: cutánea o subcutánea, vascular, ocular y ocasionalmente se presenta en localizaciones anatómica inusuales (ej., cerebro). En Venezuela se han reportado casos en caninos, bovinos y equinos. En este artículo se presenta una revisión actualizada de la literatura en relación a la epidemiología, ciclo de vida del agente etiológico, patogénesis, presentación clínica en animales y humanos, diagnóstico, tratamiento y los casos de pythiosis en Venezuela.

Pythiosis is a disease that occurs in humans and other mammals, such as horses, canines and cattle. The etiologic agent is Pythium insidiosum, an aquatic oomycete present in various geographic regions of the world. The cutaneous granulomatous form and gastrointestinal are common clinical presentations which predominate in infected animals. The infection can spread to other tissues (e.g. osseous and pulmonary). Human pythiosis has four clinical forms: cutaneous or subcutaneous, vascular, ocular and occasional anatomical sites may occur (e.g. brain). Cases in canines, bovines and equines have been reported in Venezuela. This article updated a review of the literature on the epidemiology, lifecycle of the etiological agent, pathogenesis, clinical presentation in animals and humans, diagnosis, treatment, and cases of pythiosis in Venezuela.