Ge/Si heterostructure diodes based on n ++ Si(100)/i-Ge/p-Ge and p ++ Si(100)/i-Ge/n-Ge stacks and intrinsic region thickness of ~350 and ~900 nm, respectively, were fabricated using a specially ...developed synthesis protocol that allows unprecedented control of film microstructure, morphology, and purity at complementary metal-oxide-semiconductor compatible conditions. From a growth and doping perspective, a main advantage of our inherently low-temperature (390°C) soft-chemistry approach is that all high-energy processing steps are circumvented. Current-voltage measurements of circular mesas (60-250 μm in diameter) show dark current densities as low as 6 ×10 -3 A/cm 2 at -1 V bias, which is clearly improved over devices fabricated under low thermal budgets using traditional Ge deposition techniques. Spectral photocurrent measurements indicate external quantum efficiencies between 30 and 60% of the maximum theoretical value at zero bias, and approaching full collection efficiency at high reverse biases. The above Ge devices are compared to analogous low-temperature-grown (350°C) Ge 0.98 Sn 0.02 diodes. The latter display much higher dark currents but also higher collection efficiencies close to 70% at zero bias. Moreover, the quantum efficiency of these Ge 0.98 Sn 0.02 diodes remains strong at wavelengths longer than 1550 nm out to 1750 nm due to the reduced band gap of the alloy relative to Ge.
Graphic
1,5-Diazaanthraquinone derivatives were synthesized employing single and double hetero Diels–Alder strategies. Their in vitro antitumour activity was assayed using three cell lines. Some of ...these compounds, specially those bearing methyl or ethyl groups at the C-3,7 positions or chloro at C-4 and methyl at C-7, showed IC
50 values in the 10
−8
M range for human lung carcinoma and human melanoma, which makes them attractive candidates for further development as anticancer agents.
El interés creciente en estos últimos años en las técnicas de reparación mitral ha llevado al desarrollo de distintos anillos de anuloplastia. En este estudio analizamos los resultados en la ...implantación del anillo Sorin Memo 3D en la reparación de la válvula mitral. Revisamos 27 pacientes sometidos a anuloplastia mitral en los años 2010 y 2011 de carácter electivo, preferente y urgente. Todos los pacientes fueron estudiados mediante ecocardiograma transesofágico preoperatorio para analizar el mecanismo de insuficiencia mitral (clasificación funcional: 7 tipo I, 13 tipo II, 2 tipo IIIa, 4 tipo IIIb y 1 con mecanismo mixto I-II). El ecocardiograma intraoperatorio demostró ausencia de insuficiencia significativa en 24 de los casos (88,9%), 2 pacientes con insuficiencia leve-moderada (7,4%) y 1 con insuficiencia moderada (3,7%), decidiéndose en este último recambio valvular mitral. Los datos del ecocardiograma de control previo al alta revalidaron los resultados intraoperatorios. No se registró ningún caso de mortalidad intrahospitalaria. Los buenos resultados obtenidos a corto plazo requieren seguimiento y estudios a más largo plazo y en series más amplias con el fin confirmar la durabilidad de los cambios tras la técnica.
The toxic effect of sublethal concentrations (1, 17.5 and 35 mg L
−1
) of pure glyphosate was evaluated on acetylcholinesterase (AChE) activity in the fish species,
Cnesterodon decemmaculatus
. Acute ...bioassays (96 h) under laboratory conditions were conducted and homogenates for each specimen corresponding to the anterior, middle and posterior body sections were performed. Fish survival was 100%, even at the highest concentration tested (35 mg L
−1
), in accordance with the low lethal toxicity reported for glyphosate. However, a significant inhibitory effect on AChE activity was recorded even for the lowest herbicide concentration tested (1 mg L
−1
), in the homogenates corresponding to the anterior body section. The inhibition ranged from 23 to 36%. The analytical determination of glyphosate in assay media by ion chromatography, was used to verify its stability. These results indicate that AChE—a neurotoxicity biomarker—in
C
.
decemmaculatus
may be affected by exposure to environmentally relevant concentrations of glyphosate.
Gills represent one of the major sites of gas exchange of fish, consequently they are in continuous close contact with the aquatic environment and its pollutants. In the present study the effects on ...gills of pejerrey fish,
Odontesthes bonariensis
, under glyphosate-based herbicide subchronic exposure were analyzed. Adult animals were exposed to sublethal concentrations of a glyphosate-based commercial formulation (1 and 10 PMG mg L
−1
, PMG: glyphosate active ingredient) for 15 days, while control group was maintained in rearing water. Ultrastructural changes in gills were observed by scanning electron microscopy (SEM). The composition of the surface epithelium and specific surface area were determined by energy dispersive spectroscopy (EDS) and N
2
(g) adsorption–desorption isotherms, respectively. The herbicide exposure induced severe alterations in gill ultrastructure, as shown in the SEM micrographs. Accordingly, an increase in surface area of the gills of exposed animals was determined. These results support that gills parameters of freshwater fish are sensitive morphological biomarkers for glyphosate exposure.
Abstract
In many jurisdictions, public safety and public health entities are working together to enhance the timeliness and accuracy of the analytical characterization and toxicology testing of novel ...synthetic opioids. The improved sharing and early detection of these analytical data are intended to inform surveillance, interdiction efforts, patient intervention and treatment, all of which are critical to curbing the opioid epidemic. Forensic practitioners working to identify novel synthetic opioids struggle to provide timely results when encountering new or unknown substances, such as the fentanyl analogs. These compounds, which mimic heroin in pharmacologic effect but can be far more potent, are inconsistently present in chemical identification libraries, and are currently largely unavailable as reference materials for analytical comparison. Additionally, federal, state and local governments as well as nongovernmental organizations require potency, toxicity and potential-for-abuse data to evaluate the potential health risks of emerging drug threats. Subsequent scheduling efforts and criminal prosecutions also require these thorough drug characterization studies. Pilot programs have demonstrated that early communication of real-time drug toxicity and analytical data significantly impacts the successful response to emerging opioids. High-quality, real-time, national-level data on chemical composition, toxicological test data, drug toxicity and overdoses, and analysis of seized materials by law enforcement are needed to track drug trends. However, the USA still lacks a national system to coordinate and communicate toxicology, medical and medical examiner and coroner data with the broader medical and law enforcement communities. Opportunities to address these gaps as well as recent advancements collected through interagency efforts and technical workshops in the toxicology and analytical chemistry communities are presented here. Opportunities for partnership, increased communication and expanding best practices to move toward an integrated, holistic analytical response are also explored.
The adsorption of model aromatic compounds (aniline and nitrobenzene) on chemically tailored activated carbons has been systematically investigated. Adsorption experiments at controlled solution pH ...conditions confirmed that both electrostatic and dispersive adsorbate/adsorbent interactions can have a significant influence on the equilibrium uptakes of ionic and nonionic adsorbate species. For aniline (a weak electrolyte), maximum uptakes were found on oxidized carbon surfaces at solution pH near the adsorbate's point of zero charge (pH
PZC
). In contrast, nondissociating nitrobenzene uptakes were enhanced on heat-treated surfaces with graphene layers unperturbed by electron-withdrawing functional groups, particularly at solution pH ~ pH
PZC
. A theoretical model that can successfully account for the observed trends is hereby proposed as a much needed predictor of the experimental conditions and adsorbent surface chemical properties that will maximize the uptake of aromatic compounds by activated carbons.
Spinel powders have been synthesized by chemical coprecipitation using two different precursors, nitrates and chlorides, and by an oxides mixture route. It has been shown that depending on the ...precursors used and the synthesis conditions pure spinel nanopowder can be obtained at different temperatures and with different levels of agglomeration. According to TEM results, the chloride route allows obtaining pure and deagglomerated spinel powders after calcination at 800°C with a submicrometer particle size. Sintered lyophilized powders obtained by a chloride route allow achieving materials with in-line transmittances close to 46% at 540nm and 83% in the infrared range.
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