Waste treatment in silicon production operations

A battery of special burners, each adapted for the treatment of a particular range of waste material formed during the conversion of metallurgical grade silicon to high purity silane and silicon, is accompanied by a series arrangement of filters to recover fumed silica by-product and a scrubber to recover muriatic acid as another by-product. All of the wastes are processed, during normal and plant upset waste load conditions, to produce useful by-products in an environmentally acceptable manner rather than waste materials having associated handling and disposal problems

Tuning the emission wavelength of Si nanocrystals in SiO2 by oxidation

Si nanocrystals (diameter 2–5 nm) were formed by 35 keV Si + implantation at a fluence of 6 × 1016 Si/cm2 into a 100 nm thick thermally grown SiO2 film on Si (100), followed by thermal annealing at 1100 °C for 10 min. The nanocrystals show a broad photoluminescence spectrum, peaking at 880 nm, attributed to the recombination of quantum confined excitons. Rutherford backscattering spectrometry and transmission electron microscopy show that annealing these samples in flowing O2 at 1000 °C for times up to 30 min results in oxidation of the Si nanocrystals, first close to the SiO2 film surface and later at greater depths. Upon oxidation for 30 min the photoluminescence peak wavelength blueshifts by more than 200 nm. This blueshift is attributed to a quantum size effect in which a reduction of the average nanocrystal size leads to emission at shorter wavelengths. The room temperature luminescence lifetime measured at 700 nm increases from 12 µs for the unoxidized film to 43 µs for the film that was oxidized for 29 min

In situ real-time analysis of alloy film composition and segregation dynamics with parallel detection reflection electron energy loss spectroscopy

Real-time measurements of GexSi1 – x/Si(001) composition and segregation dynamics in Sn/Si(001) in molecular beam epitaxy are demonstrated using parallel detection reflection electron energy loss spectroscopy. Parallel detection enables quantitative acquisition of low-loss spectra in a time of < 500 µs and surface composition determination in GexSi1 – x/Si(001) via Ge L2,3 core loss analysis to a precision of approximately 2% in time of order 1 s. Segregation and trapping kinetics of monolayer thickness Sn films during Si epitaxy on Sn-covered Si(100) has also been studied using the Sn M4.5 core loss

Cyclin D-Cdk4,6 Drives Cell-Cycle Progression via the Retinoblastoma Protein's C-Terminal Helix.

The cyclin-dependent kinases Cdk4 and Cdk6 form complexes with D-type cyclins to drive cell proliferation. A well-known target of cyclin D-Cdk4,6 is the retinoblastoma protein Rb, which inhibits cell-cycle progression until its inactivation by phosphorylation. However, the role of Rb phosphorylation by cyclin D-Cdk4,6 in cell-cycle progression is unclear because Rb can be phosphorylated by other cyclin-Cdks, and cyclin D-Cdk4,6 has other targets involved in cell division. Here, we show that cyclin D-Cdk4,6 docks one side of an alpha-helix in the&nbsp;Rb C terminus, which is not recognized by cyclins E, A, and B. This helix-based docking mechanism is shared by the p107 and p130 Rb-family members across metazoans. Mutation of the Rb C-terminal helix prevents its phosphorylation, promotes G1 arrest, and enhances Rb's tumor suppressive function. Our work conclusively demonstrates that the cyclin D-Rb interaction drives cell division and expands the diversity of known cyclin-based protein docking mechanisms

Air-gap gating of MgZnO/ZnO heterostructures

The adaptation of “air-gap” dielectric based field-effect transistor technology to controlling the MgZnO/ZnO heterointerface confined two-dimensional electron system (2DES) is reported. We find it possible to tune the charge density of the 2DES via a gate electrode spatially separated from the heterostructure surface by a distance of 5 μm. Under static gating, the observation of the quantum Hall effect suggests that the charge carrier density remains homogeneous, with the 2DES in the 3 mm square sample the sole conductor. The availability of this technology enables the exploration of the charge carrier density degree of freedom in the pristine sample limit

Air-gap gating of MgZnO/ZnO heterostructures

The adaptation of “air-gap” dielectric based field-effect transistor technology to controlling the MgZnO/ZnO heterointerface confined two-dimensional electron system (2DES) is reported. We find it possible to tune the charge density of the 2DES via a gate electrode spatially separated from the heterostructure surface by a distance of 5 μm. Under static gating, the observation of the quantum Hall effect suggests that the charge carrier density remains homogeneous, with the 2DES in the 3 mm square sample the sole conductor. The availability of this technology enables the exploration of the charge carrier density degree of freedom in the pristine sample limit

La atención sanitaria a pacientes con multimorbilidad. La percepción de los profesionales

Objetivo Explorar las percepciones de los profesionales sanitarios sobre las características de la atención sanitaria a pacientes con multimorbilidad. Diseño Estudio cualitativo de trayectoria fenomenológica realizado entre enero y septiembre de 2015 mediante 3 entrevistas grupales (grupos de discusión) y 15 individuales. Emplazamiento Servicio Aragonés de Salud. Participantes Profesionales médicos y de enfermería del Servicio Aragonés de Salud pertenecientes a distintos servicios: Medicina Interna, Atención Primaria, Urgencias y Gestión. También se incluyó un farmacéutico. Métodos Se realizó un muestreo intencional no probabilístico que permitiese configurar las unidades muestrales buscando criterios de representatividad del discurso, permitiendo conocer e interpretar el fenómeno estudiado en profundidad, en sus diferentes visiones. Se entrevistó a profesionales sanitarios con perfiles diferentes que conociesen en profundidad la atención a pacientes con multimorbilidad. Las entrevistas fueron grabadas, transcritas literalmente e interpretadas, mediante el análisis social del discurso. Resultados Se identifica una cultura profesional orientada a la atención de enfermedades individuales, falta de coordinación entre especialidades, pacientes sometidos a numerosas prescripciones, Guías de Práctica Clínica y formación especialmente centradas en enfermedades individuales. Conclusiones Tanto la cultura profesional como la organización del sistema sanitario se encuentran orientadas a la atención de enfermedades individuales, lo que redunda en dificultades para ofrecer una atención más integral a los pacientes con multimorbilidad. Objective: To explore the perceptions of health professionals about the characteristics of health care for patients with multimorbidity. Design: Qualitative study of phenomenological trajectory made between January and September 2015 through 3 group interviews and 15 individual interviews. Location: Aragonese Health Service. Participants: Medical and nursing professionals of the Aragon Health Service belonging to various services: Internal Medicine, Primary Care, Emergency and Management. A pharmacist was also included. Methods: A non-probabilistic intentional sampling was carried out that allowed for the selection of professionals in terms of discourse representation criteria, allowing to know and interpret the phenomenon studied in depth, in its different visions. We interviewed health professionals with different profiles who knew in depth the characteristics of care provided to patients with multimorbidity. The interviews were recorded, transcribed literally and interpreted, through the social analysis of the discourse. Results: Professional culture oriented to individual pathologies, lack of coordination among professionals, high prevalence of multi-prescriptions, Clinical Practice Guidelines oriented to individual pathologies and specialist training focused on individual diseases. Conclusions: Both the professional culture and the organization of the healthcare system have been oriented towards the attention to individual pathologies, which results in the difficulty to offer a more integrated care to patients with multimorbidity

Life Cycle Analysis of the panela agroindustry: Intensification for its development

The research made it possible to identify sensitive environmental factors generated in all the operations carried out in an intensified panela agroindustry for the purposes of diversification, productivity, quality and safety. Results of the Environmental Impact Assessment (EIA), according to the Life Cycle Analysis (LCA) methodology show that in all impact categories, the industrial stage of the production of honey, panela and sugar, cause greater environmental impact, being the two latter the most representative. However, according to the Ecuadorian environmental legislation, the impacts of the panela agroindustry are considered to be moderate and cataloged type II, therefore it does not require intensive corrective practices. However, it requires preventive actions aimed to mitigate impacts, considering that it is a subsector of the sugar cane industry that is present as production units throughout the country, where there are favorable conditions for the cultivation of sugar cane