Degree Of Relaxation Research Articles

Comparison of sedative effectiveness of thiopental versus midazolam in reduction of shoulder dislocation.

Various sedative drugs have been proposed to control anxiety and agitation in shoulder dislocation, but none of them has been diagnosed as the best sedative and relaxant agent. The study aimed to compare the sedative effectiveness of thiopental versus midazolam in reduction of shoulder dislocation. A randomized double-blind controlled trail was performed in 80 patients with shoulder dislocation recruited from the emergency department. Ten patients were excluded and 70 patients were enrolled in the study. Case group received intravenous thiopental 2 mg/kg+2 µg/kg fentanyl while control group received intravenous midazolam 0.1 mg/kg+2 µg/kg fentanyl. Number of times, patients and physician's satisfaction, difficulty of procedure, degree of muscle relaxation, time of sedation and complete recovery, number of patients with apnea episode, O2 saturation, patient's pain score and adverse events were all recorded. Muscular tone had significant difference between the two groups (P-value=0.014) and thiopental was more muscle relaxant than midazolam. Replacement of shoulder dislocation in thiopental group was easier than midazolam group (P-value=0.043). There was no need to use multiple methods of reduction in either group. Before drug infusion the mean±SD VAS scores were 8.37±2.21 in the midazolam group (A) and 8.94±1.78 in the thiopental group (B); mean difference 0.57, 95% CI= -0.38 to 1.52. After completion of the procedure, the mean±SD VAS scores in group (A) and (B) were 3.20±1.30 vs. 3.65±1.30; mean difference -0.45, 95% CI= -1.07 to 0.16. Thiopental might be more effective and relaxant than midazolam for reduction of shoulder dislocation.

Analysis of dependence of internal damping on temperature of austenitic steels

The processes of microplasticity and energy scattering inside the material are analyzed by measuring the internal damping. The mechanism of microplasticity can be evaluated by various dependencies – frequency, time, temperature and amplitude dependencies that characterize the kinetics of accumulation of fatigue damage under long-term load. By measuring the energy scattering in the material, the elastic characteristics, the modulus of elasticity, the degree of stress relaxation in the material can be determined. The ability of a solid to irreversibly disperse energy under mechanical stress is called the internal damping. The time required to achieve the equilibrium deformation value is determined by various processes associated with the reallocation of atoms, magnetic moments and the temperature of the solid subjected to external stresses. The internal damping mechanisms have been studied by ultrasonic resonant apparatus at a frequency close to 20450 Hz and in a temperature range from 30 °C up to 400 °C. Specimens of an hour glass shape were used for experiments. Measurement of internal damping dependence on temperature was performed on austenitic steels AISI 316L, AISI 316Ti and AISI 304, in the initial state and after the deformation. Those materials are commercially available stainless steels, which are very often used as biomaterials in medicine.

SoftCorner: Relaxation of Corner Values for Deterministic Static Timing Analysis of VLSI Systems

We propose SoftCorner , which is a novel approach to estimate the worst delay ( $3\sigma $ delay) of a VLSI system. SoftCorner is a modification of deterministic static timing analysis to overcome its tendency to give pessimistic estimates of the system delays when it uses $3\sigma $ corner delays for logic gates. The basic idea of SoftCorner is to use corner delays that are relaxed to $ . To select the relaxed gate delays, SoftCorner uses the delay information obtained from the K most-critical paths and then determines the degree of relaxation, and constructs a model that represents the probability that the delay of each logic gate is selected. This probability model is used to guide the selection of gate delays; the worst system delay with relaxed delay criterion can be obtained by running the selection module until the mean of the results converges. SoftCorner can also estimate the system delay at an arbitrary percentile. In experiments, SoftCorner estimated the system delay of benchmark circuits at 99.87th, 95th, and 85th percentiles with an average error $5.89 \times 10^{4}$ times faster than the MC simulation on average.

Different dissociative anesthesia protocols for coatis (Nasua nasua)

This study evaluated the effects of various combinations of dissociative drugs, tranquilizers, and sedatives in four male coatis (Nasua nasua) with an average age and weight of 4.8 ± 1.3 years and 6.02 ± 0.56 kg, respectively. We studied six groups with different anesthetic protocols: CX (10 mg/kg ketamine-S and 2 mg/kg xylazine); CXA (10 mg/kg ketamine-S, 2 mg/kg xylazine, and 0.04 mg/kg atropine); CM (10 mg/kg ketamine-S and 0.5 mg/kg midazolam); CMAc (10 mg/kg ketamine-S, 0.5 mg/kg of midazolam, and 1 mg/kg acepromazine); C(20)M (20 mg/kg of ketamine-S and 0.5 mg/kg midazolam); and TZ (7 mg/kg of tiletamine and zolazepam), with a 30-day interval between the completion of each procedure. We evaluated heart rate (HR), respiratory rate (RR), saturation of oxyhemoglobin (SpO2), body temperature T (°C), and muscle relaxation, using a scoring system. There was no statistical difference for SpO2. T (°C) was progressively reduced over time in all groups (p< 0.0001). The groups CM, C(20)M, CMAc, and TZ demonstrated the greatest effect on HR and T (°C). With respect to respiratory rate reduction, groups CM and TZ showed similar results. The best degree of muscle relaxation was observed in groups CM and C(20)M. We concluded that the combination of 20 mg/kg ketamine and midazolam 0. 5 mg/kg (group C(20)M) is an option for dissociative anesthesia of coatis, producing smaller changes in T (°C) and HR, and promoting better muscular relaxation when compared to other combinations.

Strain relaxation in convex-graded InxAl1-xAs (x = 0.05–0.79) metamorphic buffer layers grown by molecular beam epitaxy on GaAs(001)

This paper presents a study of structural properties of InGaAs/InAlAs quantum well (QW) heterostructures with convex-graded InxAl1-xAs (x = 0.05–0.79) metamorphic buffer layers (MBLs) grown by molecular beam epitaxy on GaAs substrates. Mechanisms of elastic strain relaxation in the convex-graded MBLs were studied by the X-ray reciprocal space mapping combined with the data of spatially-resolved selected area electron diffraction implemented in a transmission electron microscope. The strain relaxation degree was approximated for the structures with different values of an In step-back. Strong contribution of the strain relaxation via lattice tilt in addition to the formation of the misfit dislocations has been observed for the convex-graded InAlAs MBL, which results in a reduced threading dislocation density in the QW region as compared to a linear-graded MBL.

Anaesthetic and cardiorespiratory effects of ketamine plus dexmedetomidine for chemical restraint in black capuchin monkeys (Sapajus nigritus)

AIMS: To evaluate the quality of anaesthesia and cardiorespiratory effects of ketamine and two doses of dexmedetomidine in captive black capuchin monkeys (Sapajus nigritus) undergoing routine clinical examination.METHODS: Twenty-four animals undergoing routine clinical examination were enrolled in the study. Animals were briefly physically restrained and examined to ensure no obvious illness was present and that they were healthy. Monkeys were randomly allocated to two groups (n=12 per group) and then treated with a combination of I/M 7.5 mg/kg ketamine and either 30 µg/kg or 50 µg/kg dexmedetomidine (Dex30 or Dex50 groups, respectively). Interval to onset and duration of anaesthesia were recorded, and the quality of induction of anaesthesia and recovery were subjectively evaluated. Heart rate, respiratory rate, systolic arterial pressure (SAP), rectal temperature, degree of sedation, analgesia, muscle relaxation and response to auditory stimulus were measured every 5 minutes from onset of anaesthesia until recovery.RESULTS: The mean interval to onset of anaesthesia was 7.3 (SD 6.6) and 9.1 (SD 5.0) minutes for the Dex30 and Dex50 groups, respectively (p=0.208). Mean duration of anaesthesia was longer for monkeys in the Dex50 (85.5 (SD 15.3) minutes) compared to those in Dex30 (63.9 (SD 16.4) minutes) group (p=0.003). Induction was considered excellent in 23/24 animals, and recovery was excellent in all animals. Heart rate, respiratory rate and body temperature decreased in both groups when compared to baseline, with no differences between groups. No differences between groups were found for assessments of sedation, analgesia, muscle relaxation or response to auditory stimulus.CONCLUSION AND CLINICAL RELEVANCE: Administration of ketamine and dexmedetomidine at the two doses produced adequate, dose-dependent chemical restraint, with excellent induction and recovery, and minimal clinically significant cardiorespiratory effects in captive capuchin monkeys. Due to the occurrence of arrhythmias, electrocardiographic monitoring is recommended when this combination is used. The administration of higher doses of dexmedetomidine produced longer lasting anaesthesia without further compromise of cardiorespiratory parameters.

Improving Interval Weight Estimations in Interval AHP by Relaxations

From the viewpoint that the vagueness of a decision maker’s evaluation causes inconsistencies in a pairwise comparison matrix, interval weights have been estimated using the interval AHP. However, the estimated interval weights are often insufficient to express the vagueness of the decision maker’s evaluation. We propose three modified estimation methods for interval weights. The first is based on a relaxation of the optimality of estimated interval weights in the conventional method. The second employs a modified objective function and the third is based on a relaxation of the optimality with respect to the modified objective function. Two of the proposed methods include parameters with degrees of relaxation. Through numerical experiments with 100,000 pairwise comparison matrices generated from 100 true interval weight vectors, we demonstrate the advantages of the proposed methods over the conventional method, and determine the best method and the suitable degree of relaxation.

Evaluation of three chemical immobilization protocols in golden-headed lion tamarins (Leontopithecus chrysomelas) undergoing vasectomy surgery.

The golden-headed lion tamarin (Leontopithecus chrysomelas), originally endemic to Bahia, was introduced in Rio de Janeiro. The species is currently found in remaining forests within the region of original occupation of the golden lion tamarin (Leontopithecus rosalia), which may compromise the survival of the golden lion tamarin. Groups of golden-headed lion tamarins were captured and translocated to Bahia. However, the area chosen reached its limit and males underwent to vasectomy procedures. Animals were separated into 3 groups: S-ketamine and midazolam, S-ketamine and dexmedetomidine, and racemic ketamine and dexmedetomidine. Heart rate, sedation and muscle relaxation degrees, antinociception, and lidocaine consumption presented significant difference between midazolam and dexmedetomidine groups. Bradycardia was present on dexmedetomidine groups, with values remaining within the normal range. Dexmedetomidine groups present the best outcomes for muscle relaxation, sedation, and antinociception and were safe for vasectomy surgery in golden-headed lion tamarins.

Synthesis of Water-Dispersible Mn2+ Functionalized Silicon Nanoparticles under Room Temperature and Atmospheric Pressure for Fluorescence and Magnetic Resonance Dual-Modality Imaging.

Silicon nanoparticles (Si NPs) have been widely used in fluorescence imaging. However, rigorous synthesis conditions and the single modality imaging limit the further development of Si NPs in the field of biomedical imaging. Here, we reported a method for synthesizing water-dispersible Mn2+ functionalized Si NPs (Mn-Si NPs) under mild experimental conditions for fluorescence and magnetic resonance dual-modality imaging. The whole synthesis process was completed under room temperature and atmospheric pressure, and no special and expensive equipment was required. The synthetic nanoparticles, with favorable pH stability, NaCl stability, photostability, and low toxicity, emitted green fluorescence (512 nm). At the same time, the nanoparticles also demonstrated excellent magnetic resonance imaging ability. In vitro, their T1-weighted magnetic resonance imaging effect was obvious, and the value of longitudinal relaxation degree r1 reached 4.25 mM-1 s-1. On the basis of their good biocompatibility, Mn-Si NPs were successfully used for the fluorescence imaging as well as magnetic resonance imaging in vivo.

Bi-Parabolic Graded Buffer Layers for Metamorphic Devices

Metamorphic semiconductor devices such as high electron mobility transistors (HEMTs), light-emitting diodes (LEDs), laser diodes, and solar cells are grown on mismatched substrates and typically exhibit a high degree of lattice relaxation. Linearly-graded buffer layers are commonly used to accommodate the lattice mismatch in these structures, but theoretical and experimental studies suggest that non-linear compositional grading might allow lower threading dislocation densities and improved device performance. In this work we have compared the threading dislocation densities in heterostructures employing bi-parabolic, linear, and S-graded (complementary error function) buffer layers. The threading dislocation densities were calculated using the approximate Matthews, Mader, and Light model (1) for plastic flow and by assuming that the coefficient for second-order annihilation and coalescence reactions between threading dislocations is equal to the length of misfit dislocations.

Lithology-controlled stress variations and pad-scale faults: A case study of hydraulic fracturing in the Woodford Shale, Oklahoma

We have conducted an integrated study to investigate the petrophysical and geomechanical factors controlling the effectiveness of hydraulic fracturing (HF) in four subparallel horizontal wells in the Mississippi Limestone-Woodford Shale (MSSP-WDFD) play in Oklahoma. In two MSSP wells, the minimum horizontal stress [Formula: see text] indicated by the instantaneous shut-in pressures of the HF stages are significantly less than the vertical stress [Formula: see text]. This, combined with observations of drilling-induced tensile fractures in the MSSP in a vertical well at the site, indicates that this formation is in a normal/strike-slip faulting stress regime, consistent with earthquake focal mechanisms and other stress indicators in the area. However, the [Formula: see text] values are systematically higher and vary significantly from stage to stage in two WDFD wells. The stages associated with the abnormally high [Formula: see text] values (close to [Formula: see text]) were associated with little to no proppant placement and a limited number of microseismic events. We used compositional logs to determine the content of compliant components (clay and kerogen). Due to small variations in the trajectories of the horizontal wells, they penetrated three thin, but compositionally distinct WDFD lithofacies. We found that [Formula: see text] along the WDFD horizontals increases when the stage occurred in a zone with high clay and kerogen content. These variations of [Formula: see text] can be explained by various degrees of viscous stress relaxation, which results in the increase in [Formula: see text] (less stress anisotropy), as the compliant component content increases. The distribution of microseismic events was also affected by normal and strike-slip faults cutting across the wells. The locations of these faults were consistent with unusual lineations of microseismic events and were confirmed by 3D seismic data. Thus, the overall effectiveness of HF stimulation in the WDFD wells at this site was strongly affected the abnormally high HF gradients in clay-rich lithofacies and the presence of preexisting, pad-scale faults.

Relaxation Dynamics and Strain Persistency of Azobenzene‐Functionalized Polymers and Actuators

AbstractThe accumulation of photoinduced deformation in azobenzene functionalized polymers has received a significant amount of attention in recent years. Critically, the induced photomechanical deformation in these systems experiences varying degrees of relaxation. Control over the persistence of photomechanical strains is vital to the broader utility of these materials in shape programmable systems including soft robotics and engineered origami. Furthermore, investigations of relaxation in light responsive polymer systems triggered by UV light are more prominent than those triggered by blue‐green light. In this study, the impact of chain mobility and initially induced photostrain on the relaxation dynamics of azobenzene‐functionalized polyimides after irradiation with blue light is examined. A modeling effort coupling chromophore population dynamics to material strain is carried out to further explore the relationship between material structure, relaxation dynamics, and macroscopic deformation. The implications for controlling strain persistence are highlighted by simulating one example of a photoprimed bistable actuator.

Structure and dielectric properties of (Ba0.7Sr0.3)1−x Na x (Ti0.9Sn0.1)1−x Nb x O3 ceramics

(Ba0.7Sr0.3)1−x Na x (Ti0.9Sn0.1)1−x Nb x O3 ceramics with compositions x = 0.6, 0.7, 0.8 and 0.9 were synthesized using the solid-state reaction method. These ceramics were examined by X-ray diffraction and dielectric measurements over a broad temperature and frequency ranges. X-ray diffraction patterns revealed a single-perovskite phase crystallized in a cubic structure, for x < 0.8, and in tetragonal, for x ≥ 0.8, with Pm3m and P4mm spaces groups, respectively. Two types of behaviors, classical ferroelectric or relaxor, were observed depending on the x composition. It is noted that temperatures T C (the Curie temperature) or T m (the temperature of maximum permittivity) rise when x increases and the relaxor character grows more significantly when x composition decreases. To analyze the dielectric relaxation degree of relaxor, various models were considered. It was proven that an exponential function could well describe the temperature dependence of the static dielectric constant and relaxation time.

Growth of strained Si/relaxed SiGe heterostructures on Si(110) substrates using solid-source molecular beam epitaxy

A strained Si/relaxed SiGe heterostructure grown on Si(110) substrate is attractive as a platform for high-hole-mobility Si-based electronic devices. To improve the electrical property, a smoother surface is desirable. In this study, we investigated surface morphology and microstructural aspects of strained Si/relaxed SiGe/Si(110) heterostructures grown by solid-source (SS) molecular beam epitaxy (MBE). It was revealed that SSMBE provides a way to grow strained Si/relaxed SiGe heterostructures with smooth surfaces. In addition, it was found that the strain in the SiGe layer of the SSMBE-grown sample is highly anisotropic whereas that of the GSMBE-grown sample is almost biaxially relaxed. Along with the surface morphology, the symmetry in degree of strain relaxation has implications for the electrical property. Results of a calculation shows that anisotropic strain is preferable for device application since it confines holes solely in the strained Si layer where hole mobility is enhanced.

InxAl1–xN/Al0.53Ga0.47N multiple quantum wells on Al0.5Ga0.5N buffer with variable in-plane lattice parameter

The structural and luminescent properties of InxAl1–xN/Al0.53Ga0.47N multiple quantum wells (MQW) grown on an Al0.5Ga0.5N buffer partially relaxed with respect to an underlying AlN-template are reported. A significant redshift and improvement of ultraviolet (UV) photoluminescence (PL) intensity is found for InAlN MQWs grown on AlGaN buffers with higher relaxation degree. This is attributed to a higher QW indium incorporation as confirmed also by X-ray diffraction (XRD). The nature of room temperature time resolved PL is studied and discussed from the point of view of the possibility of a type I–type II band lineup transition in the InAlN–AlGaN system.

Evolution of relaxor properties in lanthanum (La) doped barium zirconate titanate

ABSTRACTLa doped BZT ceramics were synthesized by solid state reaction route. XRD and SEM indicated predominantly single phase microstructure. Raman spectroscopy supported La doping at A-site. Dielectric properties revealed a diffuse phase transition in Ba(Ti0.8Zr0.2)O3. La doping of 1 atomic % enhanced the FWHM to 200 K at a frequency of 1 kHz. Further increase in La doping introduced relaxor properties but FWHM was reduced. Relaxor properties were evaluated by modified Curie-Weiss law. The degree of relaxation increased from 1.31 to 2.07 as the La doping was increased from 0 to 3 atomic %, thereby yielding a complete relaxor phase.

Antimicrobial properties and release of cinnamaldehyde in bilayer films based on polylactic acid (PLA) and starch

Cinnamaldehyde (CIN) loaded amorphous PLA films were obtained by casting, using ethyl acetate as solvent. Likewise, bilayer films were obtained by thermocompression of the PLA active layer and compression moulded cassava starch (S) films or semi crystalline PLA films. Starch-PLA laminated materials were considered to improve the barrier capacity (high oxygen barrier through the starch layer and high water vapour capacity through the polyester layer), while CIN incorporation confers antimicrobial activity on the films. The PLA bilayers were obtained for comparison purposes. The antimicrobial activity of the CIN loaded PLA films and S bilayer films was proved against Escherichia coli and Listeria Innocua through in vitro tests, which indicates that the active amount released into the growth medium exceeded the minimum inhibitory concentration (MIC) of both bacteria. The release kinetics of the active compound in different food simulants demonstrated that a part of CIN was tightly bonded to the PLA matrix, whereas the free compound diffused more easily through the starch layer, making S bilayers more active against the bacteria when the starch layer was in direct contact with the culture medium. CIN entrapped in PLA bilayers did not exhibited any antibacterial effect due to its release inhibition, associated to its bonding within the PLA matrix and the lower degree of relaxation in the semi crystalline PLA layer in contact with the food simulants.

Control of Ge1−x−ySixSny layer lattice constant for energy band alignment in Ge1−xSnx/Ge1−x−ySixSny heterostructures

The energy band alignment of Ge1−xSnx/Ge1−x−ySixSny heterostructures was investigated, and control of the valence band offset at the Ge1−xSnx/Ge1−x−ySixSny heterointerface was achieved by controlling the Si and Sn contents in the Ge1−x−ySixSny layer. The valence band offset in the Ge0.902Sn0.098/Ge0.41Si0.50Sn0.09 heterostructure was evaluated to be as high as 330 meV, and its conduction band offset was estimated to be 150 meV by considering the energy bandgap calculated from the theoretical prediction. In addition, the formation of the strain-relaxed Ge1−x−ySixSny layer was examined and the crystalline structure was characterized. The epitaxial growth of a strain-relaxed Ge0.64Si0.21Sn0.15 layer with the degree of strain relaxation of 55% was examined using a virtual Ge substrate. Moreover, enhancement of the strain relaxation was demonstrated by post-deposition annealing, where a degree of strain relaxation of 70% was achieved after annealing at 400 °C. These results indicate the possibility for enhancing the indirect-direct crossover with a strained and high-Sn-content Ge1−xSnx layer on a strain-relaxed Ge1−x−ySixSny layer, realizing preferable carrier confinement by type-I energy band alignment with high conduction and valence band offsets.

Bi-Parabolic Graded Buffer Layers for Metamorphic Devices

Metamorphic semiconductor devices such as high electron mobility transistors (HEMTs), light-emitting diodes (LEDs), laser diodes, and solar cells are grown on mismatched substrates and typically exhibit a high degree of lattice relaxation. In order to minimize the incorporation of threading defects it is common to use a linearly-graded buffer layer to accommodate the mismatch between the substrate and device layers. However, some work has suggested that buffer layers with non-linear grading could offer higher performance in terms of limiting the surface density of threading defects. In this work, we compare bi-parabolic graded buffer layers to linear and S-graded buffer layers in terms of the surface threading dislocation density by considering a uniform InGaAs layer grown on a GaAs substrate with an intermediate graded InGaAs buffer layer. The threading dislocation densities were calculated using the LMD model, in which the coefficient for second-order annihilation and coalescence reactions between threading dislocations is considered to be equal to the length of misfit dislocations.

Strains in Thermally Growing Cr&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; Films Measured &lt;i&gt;In Situ&lt;/i&gt; Using Synchrotron X-Rays

This work takes place in the general context of a better understanding of materials degradation mechanisms in extreme environments. In particular, the aim of the present study was to correlate microstructural elements to growth stress magnitude evolution and stress release mechanisms for thermally grown chromia thin films on NiCr alloys. Strains in thermally grown oxides have been measured in-situ, as the oxides develop and evolve. Data have been acquired from oxides grown for different high temperatures evolutions on NiCr model alloys that form Cr2O3. Using synchrotron X-Ray at the ESRF (Beamline BM02) coupled with an induction furnace, Debye-Scherrer diffraction patterns from the oxidizing specimen were recorded in air at temperature between 700-1000°C and during cooling. The distortion of the diffraction rings was analyzed to yield the in-plane strain. Thermal stresses imposed on Cr2O3/NiCr by abruptly reducing the sample temperature for a period of time, exploiting the thermal expansion difference between oxide and substrate, showed noticeable subsequent stress relaxation by creep. Such a mechanism was monitored using time-dependent in situ measurements of strain relaxation in the oxide. The main results obtained from these experiments are the kinetic of the growth stress from the isothermal measurements (isothermal plateau), and the study of the stress release mechanism after the low-temperature jumps. In complement, the oxide microstructure development during the course of oxidation is also investigated from both the peaks intensity and width evolution. In all cases, the steady stage growth strain was relatively low and compressive. Different degrees of relaxation were also found on cooling depending on scale microstructure through the variation of the initial oxidation conditions. Results are compared with other reports of residual stresses evolution in Cr2O3 scales.