Performance model of Shams I solar power plant

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.A study of Shams I solar power plant in Abu Dhabi has been conducted to generate a performance model via a spreadsheet. The plant consists of 192 loops containing single-axis parabolic trough collectors. These collectors track the sun and focus sunlight onto a Heat Transfer Fluid (HTF) flowing in an absorber running in their focal line. That causes the temperature of the HTF to rise, which then heats the water flowing in a separate loop. This results in the formulation of vapor that is sent to a turbine. A generator is connected to the shaft of the turbine and it generates electricity due to the rotation of the shaft (caused by the expanding steam) [1]. The spreadsheet computes the annual output of the plant in1-hour increments. Input data columns include: solar radiation, ambient temperature, humidity, wind speed, time of day, day of year, and other geographical and optical constants.dc201

Complete Versus Incomplete Surgical Resection in Intramedullary Astrocytoma: Systematic Review with Individual Patient Data Meta-Analysis

Study Design: Systematic review Background: Considering the infiltrative nature of intramedullary astrocytoma, the goal of surgery is to have a better patient related outcome. Objective: To compare the overall survival (OS) and neurologic outcomes of complete vs incomplete surgical resection for patients with intramedullary astrocytoma. Methods: A comprehensive search of MEDLINE, CENTRAL and EMBASE was conducted by two independent reviewers. Individual patient data (IPD) analysis and multivariate Cox Proportional Hazard Model was developed to measure the effect of surgical strategies on OS, post-operative neurological improvement (PNI), and neurological improvement in the last follow up (FNI). Results: We included 1079 patients from 35 studies. Individual patient data of 228 patients (13 articles) was incorporated into the integrative IPD analysis. Kaplan-Meier survival analysis showed complete resection (CR) significantly improved OS in comparison with the incomplete resection (IR) (log-rank test, P =.004). In the multivariate IPD analysis, three prognostic factors had significant effect on the OS: (1) Extent of Resection, (2) pathology grade, and (3) adjuvant therapy. We observed an upward trend in the popularity of chemotherapy, but CR, IR, and radiotherapy had relatively stable trends during three decades. Conclusion: Our study shows that CR can improve OS when compared to IR. Patients with spinal cord astrocytoma undergoing CR had similar PNI and FNI compared to IR. Therefore, CR should be the primary goal of surgery, but intraoperative decisions on the extent of resection should be relied on to prevent neurologic adverse events. Due to significant effect of adjuvant therapy on OS, PNI and FNI, it could be considered as the routine treatment strategy for spinal cord astrocytoma

Complete Versus Incomplete Surgical Resection in Intramedullary Ependymomas: A Systematic Review and Meta-analysis

Study Design: Systematic review. Objective: To compare outcomes of complete versus incomplete resection in primary intramedullary spinal cord ependymoma. Methods: A comprehensive search of the MEDLINE, CENTRAL, and Embase databases was conducted by 2 independent investigators. Random-effect meta-analysis and meta-regression with seven covariates were performed to evaluate the reason for the heterogeneity among studies. We also used individual patient data in the integrative analysis to compare complete and incomplete resection based on 4 outcomes: progression-free survival (PFS), overall survival (OS), postoperative neurological improvement (PNI), and follow-up neurological improvement (FNI). Results: A total of 23 studies were identified, including 407 cases. Significant heterogeneity among included studies was observed in risk estimates (I2 for PFS, FNI, and PNI were 49.5%, 78.3%, and 87.2%, respectively). The mean follow-up time across cases was 48.6 ± 2.35 months. Cox proportional multivariable analysis revealed that the complete resection can prolong PFS (model, hazard ratio = 0.18, CI 0.05-0.54, P =.004,) and improve the FNI (binary logistic regression, adjusted odds ratio = 16.5, CI 1.6-171, P =.019). However, PNI and OS were similar in patients with incomplete resected spinal cord ependymoma compared with complete resection (binary logistic regression respectively and Cox multivariable analysis, P >.5). Conclusion: The data presented in this study showed that OS was not significantly affected by the degree of surgery. However, complete resection of intramedullary ependymomas provides the optimal outcomes with longer PFS and better long-term neurological outcomes than incomplete resection

Complete versus incomplete surgical resection in intramedullary astrocytoma: systematic review with individual patient data meta-analysis

Study Design Systematic review Background: Considering the infiltrative nature of intramedullary astrocytoma, the goal of surgery is to have a better patient related outcome. Objective To compare the overall survival (OS) and neurologic outcomes of complete vs incomplete surgical resection for patients with intramedullary astrocytoma. Methods A comprehensive search of MEDLINE, CENTRAL and EMBASE was conducted by two independent reviewers. Individual patient data (IPD) analysis and multivariate Cox Proportional Hazard Model was developed to measure the effect of surgical strategies on OS, post-operative neurological improvement (PNI), and neurological improvement in the last follow up (FNI). Results We included 1079 patients from 35 studies. Individual patient data of 228 patients (13 articles) was incorporated into the integrative IPD analysis. Kaplan-Meier survival analysis showed complete resection (CR) significantly improved OS in comparison with the incomplete resection (IR) (log-rank test, P = .004). In the multivariate IPD analysis, three prognostic factors had significant effect on the OS: (1) Extent of Resection, (2) pathology grade, and (3) adjuvant therapy. We observed an upward trend in the popularity of chemotherapy, but CR, IR, and radiotherapy had relatively stable trends during three decades. Conclusion Our study shows that CR can improve OS when compared to IR. Patients with spinal cord astrocytoma undergoing CR had similar PNI and FNI compared to IR. Therefore, CR should be the primary goal of surgery, but intraoperative decisions on the extent of resection should be relied on to prevent neurologic adverse events. Due to significant effect of adjuvant therapy on OS, PNI and FNI, it could be considered as the routine treatment strategy for spinal cord astrocytoma

Evaluation of aerobic bacterial etiology and antibiotic susceptibility pattern of diabetic foot infections in Rasht, the North or Iran

Diabetic foot ulcers (DFU) are one of the most frequently occurred complications of patients with poor-controlled diabetes mellitus. Diabetic foot infection (DFI) is increasing as a common problem and more than half of DFUs will be eventually infected. Here, we aimed to evaluate aerobic bacterial etiology and antibiotic susceptibility pattern of DFIs. This descriptive cross-sectional study was conducted at Razi educational and remedial Hospital in the North of Iran. From March to August, 2020 patients who were diagnosed as diabetic foot ulcer and attended to Razi hospital included in the study. In this study samples were collected from infected areas of diabetic foot ulcers. Standard microbiological methods were used to identify the isolates. The disc diffusion method was used to determine antimicrobial susceptibility on Mueller-Hinton agar following the Clinical and Laboratory Standards Institute (CLSI) recommendations. Thirty-one patients enrolled in this study. They included 17 females (54.8%) and 14 males (45.2%). The mean age of patients was 62.8 years, ranging from 40 to 93 years old. Totally, six types of aerobic bacteria were isolated from patients. The most prevalent type was Escherichia coli (41.9%), followed by Klebsiella spp. (16.1%). The most effective antibiotic against Gram-negative bacteria were aminoglycosides. While, Staphylococcus aureus isolates mostly susceptible to tested antibiotics. Also, none of the isolated S. aureus were methicillin-resistance. The results of antimicrobial sensitivity showed that aminoglycosides might be suitable agents for empirical therapy in Iran. Regular monitoring of culture and sensitivity reports is required to select drugs for empiric treatment

Emerging Standards and the Hybrid Model for Organizing Scientific Events During and After The COVID-19 Pandemic

Artigo publicado em revista científica internacionalSince the beginning of 2020, the COVID-19 pandemic has dramatically influenced almost every aspect of human life. Activities requiring human gatherings have either been postponed, cancelled, or held completely virtually. To supplement lack of in-person contact, people have increasingly turned to virtual settings on-line, advantages of which include increased inclusivity and accessibility and reduction of carbon footprint. However, emerging online technologies cannot fully replace, in-person scientific events. In-person meetings are not susceptible to poor internet connectivity problems, and they provide novel opportunities for socialization, creating new collaborations, and sharing ideas. To continue such activities, a hybrid model for scientific events could be a solution offering both in-person and virtual components. While participants can freely choose the mode of their participation, virtual meetings would most benefit those who cannot attend in-person due to the limitations. In-person portions of meetings should be organized with full consideration of prevention and safety strategies including risk assessment and mitigation, venue and environmental sanitation, participant protection and disease prevention, and promoting the hybrid model. This new way of interaction between scholars can be considered as a part of a resilience system which was neglected previously and should become a part of routine practice in scientific community.info:eu-repo/semantics/publishedVersio

Significant association of TNF-α, but not other pro-inflammatory cytokines, single nucleotide polymorphisms with intervertebral disc degeneration in Iranian population

Objectives: As the important role of inflammation in pathophysiology of intervertebral disc degeneration and inconsistency regarding the role of pro-inflammatory cytokine genes SNPs, the current case-control study was designed to assess this in Iranian population. Patients and Methods: The genomic DNA of peripheral leukocytes of 76 patients and 140 healthy controls were investigated to sequence 9 SNPs of pro-inflammatory cytokine genes of interleukin 1 (IL1), interleukin 6 (IL-6), and Tumor Necrosis Factor α (TNF-α) family. Results: ‘GA’ and ‘GG’ genotype of TNF-α −308 G/A SNP were significantly associated with IVDD. While ‘GA’ was 1.93 times more frequent in patients, the ‘GG’ genotype was more common among healthy subjects (OR = 0.51, P = 0.03). The ‘G’ allele of TNF-α −238 G/A was 2.51 times more common in IVDD patients while the ‘A’ genotype was more frequent in controls with odds ratio of 0.39 (P = 0.001). Interestingly, the homozygote ‘GG’ genotype was 2.98 times more prevalent in patients (P = 0.001) while the ‘GA’ heterozygote genotype was more common in healthy individuals (OR = 0.34). The other investigated SNPs were not significantly associated with disease in this study population. Conclusion: Polymorphisms of pro-inflammatory cytokine genes could take part in IVDD pathophysiology as the result of alteration in their expression levels or structures. The current study indicated significant roles of TNF-α −308 G/A and TNF-α −238 G/A SNPs with IVDD among Iranian patients. However, this study did not show any significant association between IVDD and either of SNPs of IL-1 and IL-6 gene

Lack of association between COL1A1 and COL9A2 single nucleotide polymorphisms and intervertebral disc degeneration

Background: Collagens are the main components of the extracellular matrix of intervertebral discs. The genetic mutations in collagen genes could potentially play a causal role in pathophysiology of intervertebral disc degeneration (IVDD). In this study, we investigate the association of COL1A1 and COL9A2 single nucleotide polymorphisms (SNPs) with IVDD. Material and Methods: ninety-six Iranian IVDD patients and 94 controls matched for age and sex were included. 5 cc of peripheral blood samples were obtained for DNA extraction using the Phenol–Chloroform method. The primers for SNPs COL1A1 rs909102 and COL9A2 were designed based on the TaqMan protocol and genotyped by real-time PCR with TaqMan. Results: The ‘T’ allele, ‘CC’ and ‘TT’ genotypes of COL1A1 rs909102 were more common among patients, however not significantly. Despite the similar allele distribution of COL9A2 rs137853213 in patients and controls, the homozygote genotypes were more frequent among patients, though this was not significant either. Conclusion: The allele and genotype distributions of COL1A1 rs909102 and COL9A2 rs137853213 SNPs were not significantly associated with IVDD in an Iranian population. Keywords: Single nucleotide polymorphisms, intervertebral disc degeneration, collage