817 research outputs found
Dealing with bottled water expenditures data with zero observations: a semiparametric specification
Abstract This paper analyzes bottled water expenditures data with zero observations by employing parametric and semiparametric models. The overall results of specification tests indicate that the semiparametric model outperforms the parametric model significantly
Vertically aligned InGaN nanowires with engineered axial In composition for highly efficient visible light emission.
We report on the fabrication of novel InGaN nanowires (NWs) with improved crystalline quality and high radiative efficiency for applications as nanoscale visible light emitters. Pristine InGaN NWs grown under a uniform In/Ga molar flow ratio (UIF) exhibited multi-peak white-like emission and a high density of dislocation-like defects. A phase separation and broad emission with non-uniform luminescent clusters were also observed for a single UIF NW investigated by spatially resolved cathodoluminescence. Hence, we proposed a simple approach based on engineering the axial In content by increasing the In/Ga molar flow ratio at the end of NW growth. This new approach yielded samples with a high luminescence intensity, a narrow emission spectrum, and enhanced crystalline quality. Using time-resolved photoluminescence spectroscopy, the UIF NWs exhibited a long radiative recombination time (τr) and low internal quantum efficiency (IQE) due to strong exciton localization and carrier trapping in defect states. In contrast, NWs with engineered In content demonstrated three times higher IQE and a much shorter τr due to mitigated In fluctuation and improved crystal quality
Envelope-kinetic analysis of the electron kinetic effects on Raman backscatter and Raman backward laser amplification
The electron kinetic effects on Raman backscattering and Raman backward laser amplification were analyzed. The analysis is based on the envelope-kinetic equations of a plasma wave, which are composed of the conventional envelope equation of a fluid plasma and the kinetic term. One major goal of this paper is to close the envelope-kinetic model by analyzing the kinetic term, which was not fully covered in the previous work [M. S. Hur et al., Phys. Rev. Lett. 95, 115003 (2005)]. It was found that the closed envelope-kinetic equation in the nontrapping regime takes the same form as the envelope equation of the fluid plasma used in the three-wave model. For the closure in the trapping-dominant regime, the test particle technique is employed to calculate the kinetic term. Results from the full kinetic and test particle simulations agree well with each other, while the latter has a great advantage in computation speed. The frequency shift and resonance breaking by the trapped particles are discussed with the help of a new diagnostic inserted in the full kinetic averaged particle-in-cell code.open5
Reversible airway obstruction caused by changing the size and length of an endotracheal tube in a premature neonate with suspected tracheomalacia -A case report-
Tracheomalacia is a malformation of the tracheal membranosa. It is maintained during spontaneous breathing but can be altered by bronchoscopy or positive airway pressure. Tracheomalacia is associated with a high mortality and may cause prolonged intubation and ventilation. Here, the case of a 13-day-old infant with jejunoileal stenosis that had surgery is reported. During induction of general anesthesia, endotracheal intubation was attempted several times with different sized endotracheal tubes. Airway obstruction occurred after the endotracheal intubation. After the airway was maintained, the operation was completed. Tracheomalacia was diagnosed after otolaryngology evaluation postoperatively
Effectiveness of the Hugging Balloon Technique in Coronary Angioplasty for a Heavy, Encircling, Calcified Coronary Lesion
We report our experience in coronary angioplasty and intravascular ultrasonography (IVUS) on a heavy, encircling, calcified lesion that was not dilated with the use of a cutting balloon and a non-compliant balloon. The angioplasty was successfully performed with a simple and inexpensive hugging balloon technique
Junctional membrane inositol 1,4,5-trisphosphate receptor complex coordinates sensitization of the silent EGF-induced Ca2+ signaling
Ca2+ is a highly versatile intracellular signal that regulates many different cellular processes, and cells have developed mechanisms to have exquisite control over Ca2+ signaling. Epidermal growth factor (EGF), which fails to mobilize intracellular Ca2+ when administrated alone, becomes capable of evoking [Ca2+]i increase and exocytosis after bradykinin (BK) stimulation in chromaffin cells. Here, we provide evidence that this sensitization process is coordinated by a macromolecular signaling complex comprised of inositol 1,4,5-trisphosphate receptor type I (IP3R1), cAMP-dependent protein kinase (PKA), EGF receptor (EGFR), and an A-kinase anchoring protein, yotiao. The IP3R complex functions as a focal point to promote Ca2+ release in two ways: (1) it facilitates PKA-dependent phosphorylation of IP3R1 in response to BK-induced elevation of cAMP, and (2) it couples the plasmalemmal EGFR with IP3R1 at the Ca2+ store located juxtaposed to the plasma membrane. Our study illustrates how the junctional membrane IP3R complex connects different signaling pathways to define the fidelity and specificity of Ca2+ signaling
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