180 research outputs found
Changes in Activity and Kinetic Properties of the Proteasome in Different Rat Organs during Development and Maturation
The proteasome is considered the most important proteolytic system for removal of damaged proteins with aging. Using fluorogenic peptide substrates, the chymotrypsin-like, the trypsin-like, and the peptidylglutamyl peptidase activities of the proteasome were measured in the soluble fractions of liver, brain, and lens rat homogenates. Specific activity was significantly decreased in liver and brain homogenates with maturation of the animal, that is, from newborn (7 days old) to fertile rats (2–4 months old). Rat lens homogenate exhibited an increase in activity with maturation and also with aging. Chymotrypsin-like activity was stimulated by calcium and this proteolytic activity was significantly decreased with maturation of the rat brain. The Michaelis-Menten constant (Km) increased with age in rat liver and lens, indicating a loss of affinity for its substrates by the proteasome in the animal with maturation and aging. The present data suggest that the loss of function of the proteasome with maturation may be due to structural changes of the proteasome or a decreased content of regulatory components
The prevalence of metabolic syndrome in the north of Iran. An epidemiologic comparative study
Background and Objective: The metabolic syndrome (MetS) increases the risk of cardiovascular diseases and the main aim of this study is to explorer prevalence of it in the north of Iran with comparison of Turkman and non-Turkman ethnic groups in 2012. Material and Methods: This is a cross-sectional study that conducted on the 248 subjects aged 25-70 years (Turkman=88 and non-Turkman=160). Individuals were chosen randomly from 25 clusters. Waist circumference was measured with the subject standing at the end of normal breathing; blood pressure was measured in three times and 5 ml of venous blood drawn after 8-12 h fast in the morning for laboratory test. Biochemical analysis including fasting blood glucose, triglyceride and high-density lipoprotein (HDL) cholesterol was assayed using a commercially kit (Pars Azmoon, Karaj, Iran). ATP-III method and SPSS 16.0 software (Chicago II, USA) were used for diagnosis of MetS and for statistical analyzes, respectively. P-value < 0.05 considered statistically significant. Results: Compare to Turkman group, the mean of FBG (fasting blood glucose), triglyceride and waist circumference are 15.9 mg/dl, 30.2 mg/dl and 6.5 cm were more in non-Turkman group, respectively (P<0.05 for all). The Pearson's correlation coefficient is positive between age and MetS (r=0.287, P=0.01). Generally, MetS was common in 37.9 of subjects and it was 14.7 in non-Turkman more than in Turkman people (P=0.015). Prevalence rate of MetS in men and women was 29.7 and 43.5, respectively (P=0.001). Conclusion: In the north of Iran, the prevalence of MetS is high and it was in non-Turkman ethnic group more than in Turkman group and in women more than in men while gender differences only was shown in non-Turkman ethnic group
Multi-Way and Poly-Phase Wideband Differential Phase Shifter Based on Metamaterial Technology
This paper presents multi-way and poly-phase differential phase shifter (DPS) based on metamaterial technology to realize delay lines of equal length. The proposed phase shifter provides the required phase shift relative to the reference line over a wide bandwidth. Several DPS phase shifter designs were fabricated and tested to verify their performance. Measured results show that the proposed phase shifter has phase deviation of less than ±4° and return-loss better than 10-dB with an insertion-loss of less than 1 dB across 2.2 to 4.4 GHz
Determinant criteria for designing Health benefit package in selected countries
Health benefit package described as primary health interventions that provided with government using general funds for all regardless their financial ability. This study was aimed at determine appropriate pattern for Iran using comparative survey of Health benefit package in various countries. A review exploration was done, scholars was selected population of both developed and developing countries, required information was also extracted by articles, searches and reports of reliable sources and date were analyzed by SPSS, in brief. The vast majority frequencies was respectively allocated to accessibility (40.7%), cost- effectiveness (29.6%), prioritize, efficacy and cost (22.2%). most countries located in WHO African region were selected cost-effectiveness and accessibility, WHO southeast Asia region were selected, coverage, prioritize, efficacy and quality and finally most WHO Europeans region were elected effectiveness and services costs for including services in Health benefit package. According to most Health benefit package designer emphasis on criteria including accessibility and costeffectiveness, to design Health benefit package for Iran, these criteria must be noticed
Compact tri-band Wilkinson power divider based on metamaterial structure for Bluetooth, WiMAX, and WLAN applications
A novel Wilkinson power divider is presented in this paper for triple band operation. It comprises a П-shaped transmission-line coupled to a rectangular split ring resonator metamaterial structure. The μ-negative feature of the rectangular split ring resonator metamaterial structure is investigated by retrieving its constitutive parameters from the S-parameter response. To demonstrate the versatility of the proposed Wilkinson power divider it was designed to cover Bluetooth (2.4 GHz), WiMAX (3.5 GHz), and WLAN (5.2 GHz). The tri-band Wilkinson power divider was fabricated and its performance measured to verify the design. Good agreement between the measured and simulated data is obtained. Measured results show that the tri-band Wilkinson power divider has fractional bandwidth of 3.86%, 5.82%, and 3.89% at 2.4, 3.5, and 5.2 GHz, respectively. In addition, the rectangular split ring resonator metamaterial Wilkinson power divider has a small physical footprint (14 mm ×17.9 mm or 0.15λg×0.19λg), which is 60% smaller than conventional designs
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Ultrasound Image Filtering and Reconstruction Using DCT/IDCT Filter Structure
In this paper, a new recursive structure based on the convolution model of discrete cosine transform (DCT) for designing of a finite impulse response (FIR) digital filter is proposed. In our derivation, we start with the convolution model of DCT-II to use its Z-transform for the proposed filter structure perspective. Moreover, using the same algorithm, a filter base implementation of the inverse DCT (IDCT) for image reconstruction is developed. The computational time experiments of the proposed DCT/IDCT filter(s) demonstrate that the proposed filters achieve faster elapsed CPU time compared to the direct recursive structures and recursive algorithms for the DCT/IDCT with Arbitrary Length. Experimental results on clinical ultrasound images and comparisons with classical Wiener filter, non-local mean (NLM) filter and total variation (TV) algorithms are used to validate the improvements of the proposed approaches in both noise reduction and reconstruction performance for ultrasound images
A systematic review of the use of telemedicine in the military forces worldwide
Context: Considering the pivotal role of telemedicine in providing healthcare services for remote areas, some of the military medical centers, especially in developed countries, use different types of telemedicine programs. Objectives: The present study aimed at identifying the implemented telemedicine projects in military medicine worldwide and introducing their features. Evidence Acquisition: The current systematic review was performed in 2018. PubMed, Scopus, Embase, and Web of Science databases were searched for articles published from 2014 to 2018 by a combination of related keywords, and the related original articles were then selected based on the inclusion and exclusion criteria. Data were collected by a data extraction form, and then the data were summarized and reported based on the study objectives. Results: Of the 173 articles retrieved from the first round of search, 12 were included in the study; five (41.66) studies had used the synchronous (real-time telemedicine) method. The United States, with nine studies, had the highest number of projects in military telemedicine. Most studies (n = 7) were performed on tele-psychology and the application of telemedicine in psychology. All selected studies reported the positive effects of telemedicine on providing healthcare for military forces. Conclusions: The proper utilization of telemedicine equipment is effective in saving time for both patients and healthcare providers, reducing costs, supporting in natural disasters, and satisfying patients with military medicine. To achieve telemedicine program objectives, they should be set precisely. Considering the importance of timely healthcare services, it is suggested to utilize synchronous methods and tools such as video conferencing. © 2020, Author(s)
Semiconductor thermal and electrical properties decoupled by localized phonon resonances
Thermoelectric materials convert heat into electricity through thermally
driven charge transport in solids, or vice versa for cooling. To be competitive
with conventional energy-generation technologies, a thermoelectric material
must possess the properties of both an electrical conductor and a thermal
insulator. However, these properties are normally mutually exclusive because of
the interconnection of the scattering mechanisms for charge carriers and
phonons. Recent theoretical investigations on sub-device scales have revealed
that silicon membranes covered by nanopillars exhibit a multitude of local
phonon resonances, spanning the full spectrum, that couple with the
heat-carrying phonons in the membrane and collectively cause a reduction in the
in-plane thermal conductivitywhile, in principle, not affecting the
electrical properties because the nanopillars are external to the pathway of
voltage generation and charge transport. Here this effect is demonstrated
experimentally for the first time by investigating device-scale suspended
silicon membranes with GaN nanopillars grown on the surface. The nanopillars
cause up to 21 % reduction in the thermal conductivity while the electrical
conductivity and the Seebeck coefficient remain unaffected, thus demonstrating
an unprecedented decoupling in the semiconductor's thermoelectric properties.
The measured thermal conductivity behavior for coalesced nanopillars and
corresponding lattice-dynamics calculations provide further evidence that the
reductions are mechanistically tied to the phonon resonances. This finding
breaks a longstanding trade-off between competing properties in
thermoelectricity and paves the way for engineered high-efficiency solid-state
energy recovery and cooling
Analysis of factors influencing the ultrasonic fetal weight estimation
Objective: The aim of our study was the evaluation of sonographic fetal weight estimation taking into consideration 9 of the most important factors of influence on the precision of the estimation. Methods: We analyzed 820 singleton pregnancies from 22 to 42 weeks of gestational age. We evaluated 9 different factors that potentially influence the precision of sonographic weight estimation ( time interval between estimation and delivery, experts vs. less experienced investigator, fetal gender, gestational age, fetal weight, maternal BMI, amniotic fluid index, presentation of the fetus, location of the placenta). Finally, we compared the results of the fetal weight estimation of the fetuses with poor scanning conditions to those presenting good scanning conditions. Results: Of the 9 evaluated factors that may influence accuracy of fetal weight estimation, only a short interval between sonographic weight estimation and delivery (0-7 vs. 8-14 days) had a statistically significant impact. Conclusion: Of all known factors of influence, only a time interval of more than 7 days between estimation and delivery had a negative impact on the estimation
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