Role of interface potential barrier, Auger recombination and temporal coherence in In0.5Ga0.5As/GaAs quantum dots based p-i-n light emitting diodes

© 2018 IOP Publishing Ltd. In this work, we investigate the mechanisms that control the electroluminescence from p-i-n heterostructures containing self-assembled In 0.5 Ga 0.5 As quantum dots embedded inside a GaAs/Al 0.3 Ga 0.7 As quantum well as a function of temperature and applied bias. Our results reveal that the carrier dynamics at the interface between the quantum dot and the quantum well play a crucial role in the electroluminescence emission. At low temperatures, two distinct emission bands are observed. Initially at low bias current, we observe broad emissions from the quantum wells and wetting layers. Another dominant and sharp emission at lower energy arises from the quantum dots, but only at higher bias currents. We discuss how a potential barrier between the quantum dots and quantum well can control the density of injected carriers undergoing optical recombination. We have also investigated the role of carrier capture and escape, quantum-confined stark effect and band-filling effects in the electroluminescence emission. In addition, we demonstrate how measurements of temporal coherence of individual spectral peaks, can detect the presence of Auger recombination in quantum dots under high injection currents. Interestingly, a significant increase in the temporal coherence of quantum dot emissions is observed, which could be due to a decrease in Auger recombination with increasing temperature

Lipids Fraction from Caralluma europaea (Guss.): MicroTOF and HPLC Analyses and Exploration of Its Antioxidant, Cytotoxic, Anti-Inflammatory, and Wound Healing Effects

Caralluma europaea is a medicinal plant used in Morocco to cure a variety of illnesses. This study was conducted to determine the chemical composition, the antioxidant, antiproliferative, anti-inflammatory, and wound healing activities of C. europaea lipids. The chemical composition of C. europaea was analyzed using time-of-flight mass spectrometry and high-performance liquid chromatography. The antioxidant potential was determined using the 2,2-di-phenyl-1-picryl hydrazyl (DPPH), and ferric reducing antioxidant power (FRAP) tests. The antiproliferative effect was evaluated by MTT assay against HL60, K562, Huh-7 cancer cells, and normal Vero cells. The anti-inflammatory potential was conducted against carrageenan-induced paw edema. The wound healing effect was evaluated against skin burns for 21 days. The identified phytochemical compounds were docked for their effect on nicotinamide adenine dinucleotide phosphate oxidase, caspase-3, lipoxygenase, glycogen synthase kinase-3-β, and protein casein kinase-1. The results showed the presence of some lipids, such as linoleic acid and vitamin D3. The DPPH (IC50 = 0.018 mg/mL) and FRAP (EC50 = 0.084 mg/mL) of C. europaea lipids showed an important antioxidant effect. For the anti-inflammatory test, an inhibition of 83.50% was recorded after 6 h of treatment. Our extract showed the greatest wound retraction on the 21st day (98.20%). C. europaea lipids showed a remarkable antitumoral effect against the K562 cell line (IC50 = 37.30 µg/mL), with no effect on Vero cells (IC50 > 100 µg/mL). Lignoceric acid was the most active molecule against caspase-3 (−6.453 kcal/mol). The findings indicate the growing evidence of C. europaea as a potential treatment for several diseases

Improvement of temperature-based ANN models for solar radiation estimation through exogenous data assistance

[EN] The development of new and more precise temperature-based models for solar radiation estimation is decisive, given the immediacy and simplicity associated to their input measurements and the ubiquitous problems derived from equipment failures, maintenance and calibration, and physical and biological constraints. Further, the performance quality of empirical equations is to be questioned in a large variety of climatic contexts. As an alternative to traditional techniques, artificial neural networks (ANNs) are highly appropriate for the modelling of non-linear processes. Nevertheless, temperature-based ANN models do not always provide accurate enough solar radiation estimations as their performance depends considerably on the specific temperature/solar radiation relationships of the studied context. This paper describes a new procedure to improve the performance accuracy of temperature-based ANN models for estimation of total solar radiation on a horizontal surface (Rs) taking advantage of ancillary data records from secondary similar stations, which work as exogenous inputs. The influence on the model performance of the number of considered ancillary stations and the corresponding number of training patterns is also analyzed. Finally, these models are compared with those relying exclusively on local temperature recordings. The proposed models provide performances with lower associated errors than those which do not consider exogenous inputs. The ancillary supply is translated into a decrease around 0.1 of RMSE in the local performance. The consideration of non-measured inputs in the simple local temperature-based models, namely extraterrestrial radiation or day of the year, entails a performance accuracy improvement around 0.1 of RMSE. © 2010 Elsevier Ltd. All rights reserved.Martí Pérez, PC.; Gasque Albalate, M. (2011). Improvement of temperature-based ANN models for solar radiation estimation through exogenous data assistance. Energy Conversion and Management. 52(2):990-1003. doi:10.1016/j.enconman.2010.08.027S990100352

Negativity of the Wigner function as an indicator of nonclassicality

A measure of nonclassicality of quantum states based on the volume of the negative part of the Wigner function is proposed. We analyze this quantity for Fock states, squeezed displaced Fock states and cat-like states defined as coherent superposition of two Gaussian wave packets.Comment: 10 pages, 7 figure

A microRNA-21-mediated SATB1/S100A9/NF-κB axis promotes chronic obstructive pulmonary disease pathogenesis.

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Fatal gemcitabine-induced pulmonary toxicity in metastatic gallbladder adenocarcinoma

Gemcitabine is a chemotherapy agent that may cause unpredictable side effects. In this report, we describe a fatal gemcitabine-induced pulmonary toxicity in a patient with gallbladder metastatic adenocarcinoma. A 72-year-old patient was submitted to an elective laparoscopic cholecystectomy, and a tubular adenocarcinoma in the gallbladder was incidentally diagnosed. CT scan and ultrasound before the surgery did not show any tumor. After the surgery a Pet scan was positive for a hot-spot in the left colon. The colonic lesion was conveniently removed and the histology evaluation confirmed the diagnosis of adenocarcinoma tubular. The patient was then submitted to three sections of 1,600 mg/m2 of gemcitabine with intervals of 1 week. Three weeks later he developed severe respiratory distress. A helicoidal CT scan showed diffuse and severe interstitial pneumonitis, and lung biopsy confirmed accelerated usual interstitial pneumonia consistent with drug-induced toxicity. The patient presented unfavorable evolution with progressive worsening of respiratory function, hypotension, and renal failure. He died 1 month later in spite of methylprednisolone pulse therapy, large spectrum antimicrobial therapy, and full support of respiratory, hemodynamic and renal systems. Gemcitabine-induced pulmonary toxicity is usually a dramatic condition. Physicians should suspect pulmonary toxicity in patients with respiratory distress after gemcitabine chemotherapy, mainly in elderly patients

Досвід застосування лактагелю в практиці акушер-гінеколога

Проведене дослідження показало, що застосування молочної кислоти та глікогену спрямоване на корекцію біохімічних параметрів піхвового середовища (відновлення оптимальних значень pH), сприяє пригніченню росту анаеробних бактерій та створенню оптимальних умов для накопичення власної лактофлори, забезпечуючи колонізаційну резистентність вагінального біотопу та підвищуючи загальну ефективність лікування

Advances in prevention and therapy of neonatal dairy calf diarrhoea : a systematical review with emphasis on colostrum management and fluid therapy

Neonatal calf diarrhoea remains the most common cause of morbidity and mortality in preweaned dairy calves worldwide. This complex disease can be triggered by both infectious and non-infectious causes. The four most important enteropathogens leading to neonatal dairy calf diarrhoea are Escherichia coli, rota-and coronavirus, and Cryptosporidium parvum. Besides treating diarrhoeic neonatal dairy calves, the veterinarian is the most obvious person to advise the dairy farmer on prevention and treatment of this disease. This review deals with prevention and treatment of neonatal dairy calf diarrhoea focusing on the importance of a good colostrum management and a correct fluid therapy