71 research outputs found
Career Transitions and Trajectories: A Case Study in Computing
From artificial intelligence to network security to hardware design, it is
well-known that computing research drives many important technological and
societal advancements. However, less is known about the long-term career paths
of the people behind these innovations. What do their careers reveal about the
evolution of computing research? Which institutions were and are the most
important in this field, and for what reasons? Can insights into computing
career trajectories help predict employer retention?
In this paper we analyze several decades of post-PhD computing careers using
a large new dataset rich with professional information, and propose a versatile
career network model, R^3, that captures temporal career dynamics. With R^3 we
track important organizations in computing research history, analyze career
movement between industry, academia, and government, and build a powerful
predictive model for individual career transitions. Our study, the first of its
kind, is a starting point for understanding computing research careers, and may
inform employer recruitment and retention mechanisms at a time when the demand
for specialized computational expertise far exceeds supply.Comment: To appear in KDD 201
Effects of silver nanoparticle exposure on germination and early growth of Pinus sylvestris and Alnus subcordata
The possible ecological toxicity of silver nanoparticles (AgNP) was evaluated based on germination and growth characteristics of Pinus sylvestris and Alnus subcordata. Seeds were exposed to different concentrations of AgNP in soil (0, 10, 20, 40, 80 and 100 mg/kg) and aqueous suspension (0, 10 and 20 mg/L). Then, seed germination percentage (GP%), speed of germination (S.G), seedling length (SL), as well as fresh and dry weights (FW and DW) were measured. The results showed that low concentration of AgNP (under 80 mg/kg) could be used without detrimental effects on the germination characteristics of P. sylvestris in the soil. Nevertheless, inhibitory effect of AgNP was observed at 10 mg/L for P. sylvestris in aqueous suspension. The dissimilar results in soil and aqueous suspension were due to the organic matters and clay minerals in the soil. There was no significant difference (p<0.01) among the treatments of A. subcordata, not only in soil but also in the aqueous suspension
Association between R353Q polymorphism for coagulative factor VII and severity of coronary artery disease in Iranian population
Background: Recent research has supported the central role of coagulative factors in advancing atherosclerosis and causing coronary artery disease (CAD). The present study, for the first time, aimed to clarify the relationship between R353Q polymorphism for factor VII and the occurrence and severity of CAD in a large sample of Iranian population.Methods: Nine hundred and nineteen consecutive patients with suspected CAD, who candidated for coronary angiography in the Tehran Heart Center between January 2006 and March 2007, were examined. The number of diseased coronary vessels was determined, and the severity of CAD was assessed by the Gensini score. Genotyping was done via the PCR-RFLP method.Results: The frequency of Q and R alleles was 74.1% and 25.9% in the patients with CADand 75.2% and 24.8% in those without CAD, with an insignificant difference (p = 0.625). The frequency of Q allele in the patients with single-vessel, two-vessel, and three-vessel diseases was 72.8%, 71.5%, and 76.4%, respectively; the difference was also insignificant (p = 0.379). No relationship was observed between the distribution of the genotypes and the number of the involved coronary vessels. The average of the Gensini score was 43.39 ± 46.18 in the patients with QQ genotype, 38.87 ± 42.89 in those with QR genotype, and 55.61 ± 53.80 in the ones with RR genotype, with the difference not constituting any statistical significance (p = 0.084).Conclusions: The results suggest no association between R353Q polymorphism for factor VII and the presence or progression of CAD in the Iranian population
Correlation of resting heart rate with anthropometric factors and serum biomarkers in a population-based study: Fasa PERSIAN cohort study
BACKGROUND: There is a positive association between raised resting heart rate (RHR), and all causes of mortality and shorter life expectancy. Several serum biomarkers and some anthropometric factors can affect the resting heart rate. This study aimed to investigate the determinants of resting heart rate in a large random sample of the Iranian population. MATERIAL AND METHODS: It is a standardized, retrospective study and the subjects were chosen from the baseline survey of the Prospective Epidemiological Research Study in IrAN (PERSIAN) Fasa non-communicable disease cohort study. It was conducted from winter 2014 to summer 2019 and after obtaining informed consent from a random sample, all the eligible subjects were enrolled. All anthropometric factors and biologic laboratory factors were collected and analyzed by implement smoothly clipped absolute deviation (SCAD) linear regression and SCAD quantile regression. The comparisons between males and females were done via independent T-test. RESULTS & CONCLUSION: A total number of 9975 persons from 35 to 90 years old were included. The overall median resting heart rate was 74 (interquartile range:66-80). Mean age has no important difference between males and females (P = 0.79) but, resting heart rate was significantly higher in females (76.6 versus 71.4, P < 0.001). All anthropometric factors except wrist circumference were higher in females (P < 0.05). Age has an adverse effect on resting heart rate and also, there was a direct association between resting heart rate and systolic blood pressure and blood glucose. Alpha-blockers (coefficient = 5.2) and Beta1-blockers (coefficient = - 2.2) were the most effective drugs with positive and negative effects on resting heart rate respectively. Lower hemoglobin, obesity, and more body mass index, and more low-density lipoprotein were associated with more resting heart rate. Continuing the monitoring of this sample via our cohort study and put to action multinational prospective researches with large sample sizes and long follow-ups can lead to more precise results and better scientific judgments
Clinical Findings, Bacterial Agents, and Antibiotic Resistance in Children with Spontaneous Peritonitis in Southern Iran: An Academic Tertiary Referral Center’s Experience
Background: Spontaneous bacterial peritonitis (SBP) is a fatal complication of ascites fluid infection. The causes of SBP in children differ from those in adults, and these bacteria are frequently resistant to antibiotics. Therefore, this study investigated the clinical findings, bacterial etiology, and antimicrobial resistance in children with SBP.Methods: This study was conducted on all new pediatric ascites patients, who were admitted to the Department of Pediatric Gastroenterology, Namazi Hospital, affiliated with Shiraz University of Medical Sciences (Shiraz, Iran) from 2021 to 2022. Required data such as demographic information, and clinical information such as complete blood count (CBC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), Gram staining, blood culture by Automated Blood Culture System (BACTEC), and antibiogram of ascites fluids by disc diffusion method were all collected. Finally, the data were statistically analyzed using SPSS Software (version 26). Besides, the t test, Fisher’s exact, Mann-Whitney, and Chi square tests were used for data analysis. In all tests, P≤0.05 was considered statistically significant.Results: The present study examined 62 children with ascites of which 18 (29%) had SBP. The median (IQR) age was 2.5 (8.1) years. Thirty-four (54.8%) of the participants were girls. Abdominal pain was the most common clinical manifestation in patients (54%), and there was a significant association between abdominal pain and SBP (P=0.02). In 12 positive ascites fluid cultures, coagulase-negative staphylococci had the highest frequency (25%), followed by Escherichia coli (16.7%). Third-generation cephalosporins had a 25% sensitivity in the total positive cultures. This sensitivity was 33.3% for Gram-negative cultures and 16.6% for Gram-positive cultures.Conclusion: Although third-generation cephalosporins are recommended as the primary antibiotic for the empirical treatment of SBP, the present study found high bacterial resistance. Finally, empirical therapy should be tailored to each region’s bacterial resistance features
The association between fat mass and obesity‐associated ( FTO ) genotype and serum vitamin D level in breast cancer patients
Abstract: The preventive effect of vitamin D against breast cancer can be influenced by gene polymorphisms. This study aimed to investigate the association between serum level of 25(OH) vitamin D and FTO genotype in breast cancer patients. A cross‐sectional study was carried out on 180 newly diagnosed patients with breast cancer in Tehran, Iran. The blood samples were collected from the participants in order to assess the FTO gene rs9939609 polymorphism by the tetra‐primer amplification refractory mutation system (Tetra‐ARMS) PCR method. The serum level of 25(OH) vitamin D was measured using the direct competitive enzyme‐linked immunosorbent assay (ELISA) method. The association between vitamin D and the FTO genotype in patients with breast cancer was assessed after adjustment for cofounders. The frequency of TT, AT and AA genotypes in the breast cancer patients were 43% (n = 77), 49% (n = 89) and 8% (n = 14), respectively. All patients with higher than 40 ng/dl of serum 25(OH) vitamin D had one or two copies of FTO rs9939609 risk allele (p = 0.019). No linear association was found between the number of FTO risk allele and the level of serum vitamin D. All patients with high serum level of 25(OH) vitamin D had one or two copies of FTO rs9939609 risk allele. FTO gene polymorphisms may counteract the beneficial effects of vitamin D in breast cancer prevention. Further studies can help to better understand the genetic factors predisposing to breast cancer and their effect on the association between vitamin D and breast cancer
The Association of Fat-Mass-and Obesity-Associated Gene Polymorphism (rs9939609) With Colorectal Cancer: A Case-Control Study
Background and Aim: The association between the rs9939609 polymorphism of fat mass and obesity-associated gene (FTO) and risk of colorectal cancer is controversial. This study aims to evaluate the relationship between FTO rs9939609 polymorphism and colorectal cancer (CRC) in Iranian people. Methods: A case-control study was conducted on 125 patients with CRC and 250 healthy subjects in Tehran, Iran. Demographic data and blood samples were collected from all participants. Genotyping of rs9939609 polymorphism was performed by the tetra-primer amplification refractory mutation system-polymerase chain reaction (T-ARMS-PCR) method. Results: The occurrence of AA genotype of FTO rs9939609 polymorphism in the colorectal cancer patients was significantly higher compared to that of healthy subjects (16.4 vs. 2.9%, respectively, P=0.02). The association between the frequency of risk allele of the FTO polymorphism and CRC (B=1.67, P=0.042) remained significant after adjustment for age. Further adjustment for gender (model 2) and marital status (model 3) did not change this result (B=1.67, P= 0.042 and B=1.67, P=0.043, respectively). The results remained significant after additional adjustment for ethnicity (B=1.57, P= 0.047). Conclusion: We found a positive association between the A allele of the rs9939609 polymorphism and CRC. Future studies are required to identify the underlying mechanisms
The influence of reactive oxygen species on in vitro fertilization success
The reactive oxygen species (ROS) are one of the serious factors which negatively affect the in vitro fertilization (IVF) outcome. When the formation of ROS overcome the ability of the biological system to detoxify them, they cause damage of the cells known as oxidative stress. These oxygen derived free radicals normally are produced from mitochondria during normal oxidative respiration. Due to their highly reactive nature, ROS can combine directly with other molecules leading to their structural and functional changes which result in cellular damage. Physiologically ROS can modulate the reproductive processes such as sperm-oocyte interaction, early embryo development and implantation. However the imbalance in their presence can cause oxidative stress affecting the pregnancy outcome. Although the IVF methods are continuously developing and improving there are still not sufficient microenvironment conditions that will avoid ROS accumulation and their negative influence on IVF outcome. The source of ROS during IVF may be due to the absence of endogenous defense mechanisms or due to the use of various manipulative techniques. In that way the ROS can originate from the endogenous production from the gametes and embryos or can be the result of the external factors such as: culturing media, O2 concentration, light or the manipulation technique which has been used. One of the most important endogenous factor is increased oxidative stress in the spermatozoa which is associated with poor fertilization rate, low embryo quality and high rate of pregnancy loss. The other endogenous factors are connected with oocytes and the follicular fluid. It has been shown that higher ROS levels can trigger disruption of the oocyte cytoskeleton, affect the spindle formation, aneuploidy and embryo developmental arrest. Since embryo is a fast developing organism that needs high energy in some cases can also generate excessive amounts of ROS. Pathological levels of ROS during embryo culturing result in a low quality embryos with high fragmentation leading to low clinical pregnancy rates. To avoid the effects of the known external sources of ROS many improvements were made by additions of supplements in the culture media that reduce the ROS formation, culturing under lower O2 concentrations, reduced exposure to light and introduction of vitrification methods for cryopreservation. Although many strategies are implemented so far, there is still a need for further development of new ways to avoid the oxidative stress as much as possible during the IVF treatments. One of the future approaches to prevent the harmful oxidative stress on IVF may be optimization of the environment by using the enriched atmosphere with negative air ions.
Key words: IVF, pregnancy, ROS, fertilizatio
- …