441 research outputs found
Cyclic and Long-term Variation of Sunspot Magnetic Fields
Measurements from the Mount Wilson Observatory (MWO) are used to study the
long-term variations of sunspot field strengths from 1920 to 1958. Following a
modified approach similar to that in Pevtsov et al. (2011), for each observing
week we select a single sunspot with the strongest field strength measured that
week and then compute monthly averages of these weekly maximum field strengths.
The data show the solar cycle variation of the peak field strengths with an
amplitude of about 500-700 gauss (G), but no statistically significant
long-term trends. Next, we use the sunspot observations from the Royal
Greenwich Observatory (RGO) to establish a relationship between the sunspot
areas and the sunspot field strengths for Cycles 15-19. This relationship is
then used to create a proxy of peak magnetic field strength based on sunspot
areas from the RGO and the USAF/NOAA network for the period from 1874 to early
2012. Over this interval, the magnetic field proxy shows a clear solar cycle
variation with an amplitude of 500-700 G and a weaker long-term trend. From
1874 to around 1920, the mean value of magnetic field proxy increases by about
300-350 G, and, following a broad maximum in 1920-1960, it decreases by about
300 G. Using the proxy for the magnetic field strength as the reference, we
scale the MWO field measurements to the measurements of the magnetic fields in
Pevtsov et al. (2011) to construct a combined data set of maximum sunspot field
strengths extending from 1920 to early 2012. This combined data set shows
strong solar cycle variations and no significant long-term trend (linear fit to
the data yields a slope of 0.8 G year). On the other hand, the
peak sunspot field strengths observed at the minimum of the solar cycle show a
gradual decline over the last three minima (corresponding to cycles 21-23) with
a mean downward trend of 15 G year
Adaptive Energy Aware Cooperation Strategy in Heterogeneous Multi-domain Sensor Networks
AbstractIn some applications of sensor networks, multi-domain exists and cooperation among domains could lead to longer lifetime. In this paper, we consider heterogeneous multi-domain sensor networks. It means that different networks belong to different domains and sensors are deployed at the same physical location and their topology is heterogonous. Apparently, domains life time can be increased by means of cooperation in packet forwarding; however selfishness is inevitable from rational perspective. We investigate this problem to find out cooperation of authorities while their sensors are energy aware. When sensors are energy aware, spontaneous cooperation cannot take place. Therefore we presented the Adaptive Energy Aware strategy, a novel algorithm that is based on TIT-FOR-TAT, starts with generosity and ends up with conservative behaviour. Our simulation results showed that this algorithm could prolong its network lifetime in competition with other networks
Halotolerant Ability and α-Amylase Activity of Some Saltwater Fungal Isolates
Four halotolerant fungal isolates originating from the saltwater Lake Urmia in Iran were selected during a screening program for salt resistance and α-amylase activity. The isolates were identified based on sequencing the ITS region and a part of the β-tubulin gene, as Penicillium chrysogenum (isolate U1; CBS 132820), Fusarium incarnatum (isolate U2; CBS 132821), and Penicillium polonicum (isolate U3; CBS 132822, and isolate U4; CBS 132823). The growth of these isolates was determined by measuring the colony diameter and mycelia dry weight in Sabouraud dextrose agar and yeast nitrogen base medium supplemented with NaCl, KCl, and LiCl. Isolate U4 showed a growth up in 15% NaCl and U1 was the only isolate that could grow in 20% KCl. None of the strains grew in a media containing LiCl. The salt supplemented medium did not increase the size of colony diameter in all isolates (p > 0.05). The ability of the selected isolates for amylase production was quantitatively tested and showed that P. polonicum isolate U4 was the most potent producer of amylase with a yield of 260.9 U/L after 60 h, whereas P. polonicum isolate U3 was the lowest one with a production level of 97.9 U/L after 48 h. P. polonicum isolate U4 could be a suitable candidate for production of amylase on an industrial scale after optimization. © 2013 by School of Pharmacy
Metabolic host response and therapeutic approaches to influenza infection
Based on available metabolomic studies, influenza infection affects a variety of cellular metabolic pathways to ensure an optimal environment for its replication and production of viral particles. Following infection, glucose uptake and aerobic glycolysis increase in infected cells continually, which results in higher glucose consumption. The pentose phosphate shunt, as another glucose-consuming pathway, is enhanced by influenza infection to help produce more nucleotides, especially ATP. Regarding lipid species, following infection, levels of triglycerides, phospholipids, and several lipid derivatives undergo perturbations, some of which are associated with inflammatory responses. Also, mitochondrial fatty acid β-oxidation decreases significantly simultaneously with an increase in biosynthesis of fatty acids and membrane lipids. Moreover, essential amino acids are demonstrated to decline in infected tissues due to the production of large amounts of viral and cellular proteins. Immune responses against influenza infection, on the other hand, could significantly affect metabolic pathways. Mainly, interferon (IFN) production following viral infection affects cell function via alteration in amino acid synthesis, membrane composition, and lipid metabolism. Understanding metabolic alterations required for influenza virus replication has revealed novel therapeutic methods based on targeted inhibition of these cellular metabolic pathways
Association of interleukin 1 gene cluster and interleukin 1 receptor gene polymorphisms with ischemic heart failure
BACKGROUND: Proinfl ammatory cytokines have been known to play a considerable part in the pathomechanisms of chronic heart failure (CHF). Given the importance of proinfl ammatory cytokines in the context of the failing heart, we assessed whether the polymorphisms of interleukin (IL)-1 gene cluster, including IL-1a, IL-1β, and IL-1 receptor antagonist (IL-1RA) and IL-1R gene are predictors of CHF due to ischemic heart disease. METHODS: Forty- three patients with ischemic heart failure were recruited in this study as patients group and compared with 140 healthy unrelated control subjects. Using polymerase chain reaction with sequence-specifi c primers method, the allele and genotype frequency of 5 single nucleotide polymorphisms (SNPs) within the IL- 1a (-889), IL-1β (-511, +3962), IL-1R (psti 1970), and IL-1RA (mspa1 11100) genes were determined.RESULTS: The frequency of the IL-1β -511/C allele was signifi cantly higher in the patient group compared to that in the control group (p = 0.031). The IL-1β (-511) C/C genotype was signifi cantly overrepresented in patients compared to controls (p = 0.022). CONCLUSIONS: Particular allele and genotype in IL-1β gene were overrepresented in patients with ischemic heart failure, possibly affecting the individual susceptibility to this disease (Tab. 1, Ref. 27). Text in PDF www.elis.sk
Surveying the utilization of aluminum chloride in water treatment
Aluminum chloride (AlCl3) is an inorganic coagulant and the preset study is aimed as surveying its usage for water treatment purposes. The keywords �poly aluminum chloride�, water treatment�, and �coagulant� were searched in Google Scholar, SID, Iran Medix, and Magiran databases between 2006 and 2017. The found articles were summarized afterward. The results showed that poly aluminum chloride (PAC) can be used as an effective coagulant if the standards with regard to concentration of PAC are observed in the process of treatment. PAC can be also used to remove extra fluoride content from water resources. To have better results, adjusting PH value of the coagulation process, avoiding higher doses of PAC, adequate stirring with proper speed (to facilitate coagulation process), efficient filtration (to remove aluminum clods), using chitosan (as aid coagulant of PAC), adding bentonites (to reduce optimum concentration of PAC needed) are recommended. © 2018, Advanced Scientific Research. All rights reserved
Assessment of cardiac risk factors in medical students of tehran university
Prevention of coronary heart disease, mainly by reducing the levels of known risk factors in the population, remains a priority in public health. This cross-sectional study on randomly selected medical students during their internship was conducted from July 2001 to April 2002 in order to determine the prevalence of major coronary artery disease (CAD) risk factors. This survey was done by filling the questionnaire, measuring physical parameters, and taking a fasting blood sample. Two hundred and sixty four medical students were evaluated in this study (48 female, 216 male) with the mean age of 26.5 ± 2.8 years. The main risk factors in descending order of frequency were physical inactivity (43.5%), low high-density lipoprotein cholesterol (26.2%), family history of premature CAD (15.9%), smoking (10.3%), abdominal obesity (10.2%), high triglyceride level (5.3%), high blood pressure (3.4%), and high low-density lipoprotein cholesterol (1.5%). Also, 25% of married females were using oral contraceptives regularly. The number of risk factors per person was 2.2 on average (1.1 in females and 2.5 in males). Prevalence of CAD ri sk factors in this medical students’ population was unacceptably high. Additional studies should be done to gather more information and determine the need for preventive, educational or curative interventions
Serum levels of CTRP3 in diabetic nephropathy and its relationship with insulin resistance and kidney function
Background C1q TNF related protein 3 (CTRP3) is an adipokine secreted from adipose tissue. Previous studies have suggested that CTRP3 improves insulin sensitivity and reduces inflammation. Human studies have evaluated circulating levels of this adipokine in patients with diabetes mellitus (DM), diabetic retinopathy, metabolic syndrome, and coronary artery diseases. However, circulating levels of this adipokine in patients with diabetic nephropathy have not been evaluated. The present study aimed to assess serum levels of CTRP3 in patients with type 2 diabetes mellitus (T2DM) and diabetic nephropathy (T2DM-NP) and its relationship with metabolic and inflammatory markers. Methods This cross-sectional study was performed on 55 controls, 54 patients with T2DM, and 55 patients with T2DM-NP. Serum levels of CTRP3, adiponectin, TNF-α, and IL-6 were measured by ELISA technique. Results Serum levels of CTRP3 were significantly lower in patients with T2DM (257.61 ± 69.79 ng/mL, p < 0.001) and T2DM-NP (222.03 ± 51.99 ng/mL, p < 0.001) compared to controls (328.17 ± 80.73 ng/mL), and those with T2DM-NP compared to T2DM group. CTRP3 was independently associated with HOMA-IR (r = -0.327, p < 0.05) and adiponectin (r = 0.436, p < 0.01) in T2DM group. In T2DM-NP patients, CTRP3 independently was associated with eGFR (r = 0.428, p < 0.01) and HOMA-IR (r = -0.436, p < 0.01). Furthermore, CTRP3 revealed a ability to differentiate T2DM-NP patients from controls (area under curve (95 confidence interval): 0.881 (0.820�0.943) and p < 0.001). Conclusion Decreased serum levels of CTRP3 in patients with T2DM and diabetic nephropathy and its association with pathologic mechanism in these patients suggested a possible role for CTRP3 in pathogenesis of diabetic nephropathy; nevertheless, further studies are required in this regard. © 2019 Moradi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Examining the amount of coliform in milk and other dairy products
Food borne diseases are one of the common problems in health and public health section. Among them, bacteria are one of the most important creating factors for infections and food poisoning.so this study aimed to review the conducted studies in the field of coliform in milk and dairy products. In this study all the present articles were searched in internal databases including Iran medex, Irandoc and SID and external databases such as Google Scholar, Scopus, Science Direct, scientific database of World Health Organization (Medicos / WHO / EMR), free journal access guide (Open Access Journal Directory of), Elsiver, PubMed using the Key Words of food, milk and dairy, coliform contamination. The results of studies show that in most of tested samples, coliform contamination is greater than what observed. The findings of conducted investigations in different parts of world and Iran confirmed the high risk of various microbial contaminations in dairy products and transmission to consumers and paying more attention to the health quality of it based on pasteurization or heat applied and regardinghygienic standards during production process. © 2018, Advanced Scientific Research. All rights reserved
Is salt intake reduction a universal intervention for both normotensive and hypertensive people: a case from Iran STEPS survey 2016
Purpose: There is a direct association between salt intake and blood pressure (BP), one of the main risk factors for CVDs. However, yet there has been a debate that how strong is this association in people with and without hypertension. This study was conducted to evaluate the magnitude of the association between salt intake and BP in hypertensive and normotensive population among a nationally representative population. Methods: The study was conducted on a nationally representative sample of 18,635 Iranian adults aged 25 years and older who participated in the STEPS survey 2016 and provided urine sample. Salt intake was estimated through spot urine sample and Tanaka equation. Multiple linear regression model in survey data analysis was used to assess the independent effect of salt intake on BP. Results: After adjusting for covariates, there was a significant association between salt intake and SBP in hypertensive (p ' 0.001) and normotensive people (p ' 0.001). In hypertensive people, with 1 g of increase in salt intake, the SBP and DBP increased 0.37 mmHg and 0.07 mmHg, respectively. Whereas in normotensive people, with 1 g of increase in salt intake, the SBP and DBP increased 0.26 mmHg and 0.05 mmHg, respectively. Moreover, there was a significant trend toward an increase of SBP across salt intake quartiles in both hypertensive (p ' 0.001) and normotensive people (p = 0.002), though the slope was steeper in hypertensive than in normotensive people. Conclusions: The present study demonstrated that salt intake significantly increased SBP in both hypertensive and normotensive people, though the magnitude of this increase was greater in hypertensive people as compared with normotensive people
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