Curvature Correction of FWHM in the X-Ray Rocking Curve of Bent Heteroepitaxial Films

A method for accurate determination of the curvature radius of semiconductor thin films is proposed. The curvature-induced broadening of the x-ray rocking curve (XRC) of a heteroepitaxially grown layer can be determined if the dependence of the full width at half maximum (FWHM) of XRC is measured as a function of the width of incident x-ray beam. It is found that the curvature radii of two GaN films grown on a sapphire wafer are different when they are grown under similar MOCVD conditions but have different values of layer thickness. At the same time, the dislocation-induced broadening of XRC and thus the dislocation density of the epitaxial film can be well calculated after the curvature correction.

Environmental Kuznets Curve for SO_2 Emissions in China

This study examines the link between the economic growth and the environmental quality. Based on a panel data set, a N-shaped Environmental Kuzents Curve has been found for the sample period: a cubic relationship between per capita GDP and emissions of sulphur dioxide (SO2). We also find that energy consumption is an important determinant of environmental degradation. The empirical results suggest that we should promote environmental protection as soon as possible.

Calculating the equation of state parameters and predicting the spinodal curve of isotactic polypropylene/poly(ethylene-co-octene) blend by molecular dynamics simulations combined with Sanchez-Lacombe lattice fluid theory

Molecular dynamics simulations are adopted to calculate the equation of state characteristic parameters P*, rho*, and T* of isotactic polypropylene (iPP) and poly(ethylene-co-octene) (PEOC), which can be further used in the Sanchez-Lacombe lattice fluid theory (SLLFT) to describe the respective physical properties. The calculated T* is a function of the temperature, which was also found in the literature. To solve this problem, we propose a Boltzmann fitting of the data and obtain T* at the high-temperature limit. With these characteristic parameters, the pressure-volume-temperature (PVT) data of iPP and PEOC are predicted by the SLLFT equation of state. To justify the correctness of our results, we also obtain the PVT data for iPP and PEOC by experiments. Good agreement is found between the two sets of data. By integrating the Euler-Lagrange equation and the Cahn-Hilliard relation, we predict the density profiles and the surface tensions for iPP and PEOC, respectively. Furthermore, a recursive method is proposed to obtain the characteristic interaction energy parameter between iPP and PEOC. This method, which does not require fitting to the experimental phase equilibrium data, suggests an alternative way to predict the phase diagrams that are not easily obtained in experiments.

Volume-Time Curve: An Alternative for Endotracheal Tube Cuff Management

BACKGROUND: Despite numerous studies on endotracheal tube cuff pressure (CP) management, the literature has yet to establish a technique capable of adequately tilling the cuff with an appropriate volume of air while generating low CP in a less subjective way. the purpose of this prospective study was to evaluate and compare the CP levels and air volume required to fill the endotracheal tubes cuff using 2 different techniques (volume-time curve versus minimal occlusive volume) in the immediate postoperative period after coronary artery bypass grafting. METHODS: A total of 267 subjects were analyzed. After the surgery, the lungs were ventilated using pressure controlled continuous mandatory ventilation, and the same ventilatory parameters were adjusted. Upon arrival in the ICU, the cuff was completely deflated and re-inflated, and at this point the volume of air to fill the cuff was adjusted using one of 2 randomly selected techniques: volume-time curve and minimal occlusive volume. We measured the volume of air injected into the cuff, the CP, and the expired tidal volume of the mechanical ventilation after the application of each technique. RESULTS: the volume-time curve technique demonstrated a significantly lower CP and a lower volume of air injected into the cuff, compared to the minimal occlusive volume technique (P < .001). No significant difference was observed in the expired tidal volume between the 2 techniques (P = .052). However, when the subjects were submitted to the minimal occlusive volume technique, 17% (n = 47) experienced air leakage as observed by the volume-time graph. CONCLUSIONS: the volume-time curve technique was associated with a lower CP and a lower volume of air injected into the cuff, when compared to the minimal occlusive volume technique in the immediate postoperative period after coronary artery bypass grafting. Therefore, the volume-time curve may be a more reliable alternative for endotracheal tube cuff management.

Mast Cell Curve-Response in Partial Achilles Tendon Rupture After 830 nm Phototherapy

Objective: the aim of this study was to quantify mast cells at different time intervals after partial Achilles tendon rupture in rats treated with low-level laser therapy (LLLT). Background data: There is a high incidence of lesions and ruptures in the Achilles tendon that can take weeks and even months to heal completely. As the mast cells help in the healing repair phase, and LLLT has favorable effects on this tissue repair process, study of this modality on the quantity of mastocytes in the ruptured tendon is relevant. Methods: Sixty Wistar rats were subjected to partial Achilles' tendon rupture by direct trauma, randomized into 10 groups, and then divided into the group treated with 80mW aluminum gallium arsenide infrared laser diode, continuous wave, 2.8W/cm(2) power density, 40J/cm(2) energy density, and 1.12J total energy, and the simulation group. Both the groups were subdivided according to the histological assessment period of the sample, either 6h, 12h, 24h, 2 days, or 3 days after the rupture, to quantify the mastocytes in the Achilles' tendon. Results: the group subjected to LLLT presented a greater quantity of mastocytes in the periods of 6h, 12h, 24h, 2 days, and 3 days after rupture, compared with the simulation groups, but differences were detected between the sample assessment periods only in the simulation group. Conclusions: LLLT was shown to increase the quantity of mastocytes in the assessment periods compared with the simulation groups.

Clinical Use of the Volume-Time Curve for Endotracheal Tube Cuff Management

BACKGROUND: Previous investigation showed that the volume-time curve technique could be an alternative for endotracheal tube (ETT) cuff management. However, the clinical impact of the volume-time curve application has not been documented. the purpose of this study was to compare the occurrence and intensity of a sore throat, cough, thoracic pain, and pulmonary function between these 2 techniques for ETT cuff management: volume-time curve technique versus minimal occlusive volume (MOV) technique after coronary artery bypass grafting. METHODS: A total of 450 subjects were randomized into 2 groups for cuff management after intubation: MOV group (n = 222) and volume-time curve group (n = 228). We measured cuff pressure before extubation. We performed spirometry 24 h before and after surgery. We graded sore throat and cough according to a 4-point scale at 1, 24, 72, and 120 h after extubation and assessed thoracic pain at 24 h after extubation and quantified the level of pain by a 10-point scale. RESULTS: the volume-time curve group presented significantly lower cuff pressure (30.9 +/- 2.8 vs 37.7 +/- 3.4 cm H2O), less incidence and intensity of sore throat (1 h, 23.7 vs 51.4%; and 24 h, 18.9 vs 40.5%, P < .001), cough (1 h, 19.3 vs 48.6%; and 24 h, 18.4 vs 42.3%, P < .001), thoracic pain (5.2 +/- 1.8 vs 7.1 +/- 1.7), better preservation of FVC (49.5 +/- 9.9 vs 41.8 +/- 12.9%, P = .005), and FEV1, (46.6 +/- 1.8 vs 38.6 +/- 1.4%, P = .005) compared with the MOV group. CONCLUSIONS: the subjects who received the volume-time curve technique for ETT cuff management presented a significantly lower incidence and severity of sore throat and cough, less thoracic pain, and minimally impaired pulmonary function than those subjects who received the MOV technique during the first 24 h after coronary artery bypass grafting.