Performance simulation of solar cell based on AZO/CdTe heterostructure by SCAPS 1D software.

Simulation and analysis of solar cells based on the heterojunction of zinc oxide doped with aluminum (AZO) and cadmium telluride (CdTe) with the structure (Al/AZO/CdTe/NiO/Ni) using the Simulator of the capacitance of solar cells - 1 dimension (SCAPS-1D) has been presented in this paper. AZO is used as a window layer and Nickel oxide (NiO) has been introduced as a hole transport layer (HTL). Through the software, the effect of thickness, absorber (CdTe), and window (AZO) layers carrier concentration, operating temperature, and resistances (series and shunt) have been studied. Simulation results show that the solar cell performance can be greatly improved by adjusting the layer's thickness and carrier concentration, obtaining optimal values of 10 nm and 10 18 c m - 3 for the AZO layer, while for the CdTe layer they were 2 µm and 10 15 c m - 3 . The optimum series and shunt resistances are in the range of 1-3 Ω c m 2 and 1800-2200 Ω c m 2 respectively. A maximum power conversion efficiency (PCE) of 14.2% is achieved with an open circuit voltage (Voc) of 0.74 V, short circuit current density (Jsc) of 26.15 m A / c m 2 and a fill factor (FF) of 72.83%, this shows AZO potential to be considered as an interesting material to replace CdS window layer.

Porous Silicon Gas Sensors: The Role of the Layer Thickness and the Silicon Conductivity.

We studied the influences of the thickness of the porous silicon layer and the conductivity type on the porous silicon sensors response when exposed to ethanol vapor. The response was determined at room temperature (27 ∘C) in darkness using a horizontal aluminum electrode pattern. The results indicated that the intensity of the response can be directly or inversely proportional to the thickness of the porous layer depending on the conductivity type of the semiconductor material. The response of the porous sensors was similar to the metal oxide sensors. The results can be used to appropriately select the conductivity of semiconductor materials and the thickness of the porous layer for the target gas.

Deficiencias de anticuerpos en niños y adolescentes con infecciones recurrentes y/o graves

Introducción: Las deficiencias predominantes de anticuerpos (DPA) son inmunodeficiencias primarias caracterizadas por hipogammaglobulinemia, una disminución de niveles séricos de IgA, IgG y/o IgM, predisponiendo a infecciones recurrentes y/o graves. Las más frecuentes son la inmunodeficiencia común variable (CVID), agammaglobulinemia ligada al X (XLA), síndrome de híper IgM (HIgM) y deficiencia de IgA (DIgA). En Paraguay, los reportes sobre estas patologías son escasos. Objetivo: estudiar los niveles de inmunoglobulinas séricas en pacientes con infecciones recurrentes y/o graves en busca de DPA. Material y Métodos: Se incluyeron 143 pacientes de 1 a 17 años de edad, registrados en la base de datos del Instituto de Investigaciones en Ciencias de la Salud del 2012 al 2017, con dosajes de IgA, IgG e IgM y dato clínico de infecciones recurrentes y/o graves. Se aplicó un algoritmo internacional de diagnóstico fenotípico a los casos de hipogammaglobulinemia. Resultados: La edad promedio de los pacientes fue de 6±4 años, 54% (77/143) era de sexo masculino, un 78% (112/143) fue pacientes ambulatorios y 40% (57/143) presentó infecciones respiratorias. En el 90% (129/143) se observó valores normales de inmunoglobulinas séricas y en el 10% (14/143) se encontró hipogammaglobulinemia que correspondió a un caso de XLA, 3 casos de CVID, 5 de DIgA, 2 de HIgM, 2 deficiencias de subclases de IgG y una deficiencia selectiva de IgM. Conclusiones: Se identificaron casos de DPA cuyas frecuencias concuerdan con datos de otros países con DIgA y CVID como las más comunes. Es importante sospecharlas en niños y adolescentes con infecciones recurrentes, graves, oportunistas, y evaluar las inmunoglobulinas séricas para un diagnóstico oportuno.

Introduction: Predominantly antibody deficiencies (PAD) are primary immunodeficiencies characterized by hypogammaglobulinaemia, a decrease of IgA, IgG and/or IgM serum levels, which predispose to recurrent and/or severe infections. The most frequent are the common variable immunodeficiency (CVID), X-linked agammaglobulinaemia (XLA), hyper IgM syndrome (HIgM) and IgA deficiency (IgAD). In Paraguay, the reports about these diseases are very few. Objective: to study serum immunoglobulin levels in patients with recurrent and/or severe infections searching for PAD. Materials and Methods: 143 patients from 1 to 17 years old were included, registered in a data base from the Instituto de Investigaciones en Ciencias de la Salud from 2012 to 2017, with IgA, IgG and IgM serum levels dosages and clinical reference of recurrent and/or severe infections. An international diagnostic phenotypic algorithm was applied to the hypogammaglobulinaemia cases. Results: The average age of the patients was 6 ± 4 years, 54% (77/143) were males, 78% (112/143) were outpatients and 40% (57/143) had respiratory infections. In 90% (129/143) of the patients normal values of serum immunoglobulins were observed and in 10% (14/143) hypogammaglobulinaemia was found, corresponding to one case of XLA, 3 cases of CVID, 5 of IgAD, 2 of HIgM, 2 IgG subclasses deficiencies and one IgM selective deficiency. Conclusions: The frequency of DPA cases identified corresponds with data from other countries in which IgAD and CVID are the most common ones. It is important to suspect these pathologies in children and adolescents with recurrent, severe, opportunistic infections and evaluate their serum immunoglobulins for timely diagnostic.

Heterozygous NPR2 Mutations Cause Disproportionate Short Stature, Similar to Léri-Weill Dyschondrosteosis.

CONTEXT: SHOX mutations have been detected in approximately 70% of Léri-Weill dyschondrosteosis (LWD) and approximately 2.5% of idiopathic short stature (ISS) cases, suggesting the implication of other genes or loci. The recent identification of NPR2 mutations in ISS suggested that NPR2 mutations may also be involved in disproportionate short stature. OBJECTIVE: The objective of the study was to investigate whether NPR2 mutations can account for a proportion of the cases referred for LWD and ISS in whom no SHOX mutation was detected. PATIENTS AND METHODS: We undertook NPR2 mutation screening in 173 individuals referred for suspected LWD and 95 for ISS, with no known defect in SHOX or its enhancers. Intracellular localization and natriuretic peptide precursor C-dependent guanylate cyclase activity were determined for the identified NPR2 variants. RESULTS: Eight NPR2 variants were identified in nine individuals, seven referred for suspected LWD and two for ISS. Six were demonstrated to affect NPR-B cell trafficking and/or its ability to synthesize cyclic GMP (cGMP) under response to natriuretic peptide precursor C/brain natriuretic peptide stimulation. All pathogenic mutations were detected in the suspected LWD referral group (∼3%). Interestingly, one of these patients is currently being treated with recombinant human GH and in contrast to previous reports is showing a positive response to the treatment. CONCLUSIONS: NPR2 mutations account for approximately 3% of patients with disproportionate short stature and/or clinical or radiographic indicators of SHOX deficiency and in whom no SHOX defect has been identified. However, no patient has yet presented with Madelung deformity. Thus, NPR2 should be screened in the SHOX-negative LWD referrals.