113 research outputs found

    Computational Methods and Results for Structured Multiscale Models of Tumor Invasion

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    We present multiscale models of cancer tumor invasion with components at the molecular, cellular, and tissue levels. We provide biological justifications for the model components, present computational results from the model, and discuss the scientific-computing methodology used to solve the model equations. The models and methodology presented in this paper form the basis for developing and treating increasingly complex, mechanistic models of tumor invasion that will be more predictive and less phenomenological. Because many of the features of the cancer models, such as taxis, aging and growth, are seen in other biological systems, the models and methods discussed here also provide a template for handling a broader range of biological problems

    Investigating learning theories in social networks; providing a theoretical framework for curriculum design

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    Background and Objectives: To use social media effectively, we need to identify and apply the implications of supportive theories using social media. Different learning theories provide a variety of interpretations of learning. Different learning theories lead to diverse orientations and outcomes in curriculum planning. Therefore, learning theories serve as a framework for guiding decisions during the design and implementation of the curriculum. The aim of this study was to identify the types of learning theories that support the use of social networks and to analyze learning theories on social networks in order to provide a theoretical basis for designing curricula. Methods: For this study, qualitative content analysis method was used. The statistical population of this study consists of all valid documents related to the subject- supportive theories of learning in social networks- from 1995 to 2018 (n=30) selected based on purposeful sampling. The content of 30 documents were analyzed.  The analysis unit is the theme. To analyze the findings, the main and sub-classes were extracted after open coding. To ensure the validity of the research, the methods of review by members, triangulation of data sources and review by colleagues were used, and to ensure reliability, the agreement method between the two coders was used. Findings: The findings showed a variety of context-based, community-based, and person-centered theories that support learning on social media. The findings also include four main categories: It showed the dimensions of social networks, network interactions, types of learning, and curriculum elements. It was shown that network communication in social networks includes social interaction, interpersonal communication and interactive communication with admin and teacher-student communication, which is broad and based on community sharing, central agreement and based on sharing ideas. Types of learning on social networks include; network learning, situational learning, problem-based learning, personal learning, and indirect learning. Elements of the curriculum include; network objectives, network content, network learning environment, network inclusiveness, and network evaluation. Network Objectives; features such as unpredictability, divergence, unpredictability, variability, nonlinearity, flexibility, value, reproductive and interactive. Network content has some features such as distributed knowledge, multiplicity of resources, reliable resources, accessibility, context-based knowledge, shared knowledge, inclusive knowledge, self-centered information, voluntary knowledge creation, interchangeable content. The network environment includes technical and educational features. Among the technical features of this environment, we can mention the diversity of language, the existence of communication tools, the possibility of customizing the message and simulating communication. The educational features of this environment also include; being rich is one of the tools of knowledge management, situational awareness, personalized information, open and flexible environment. The network learner is knowledgeable and up-to-date, independent and active, able to do several things together. The network learner is an actor, and social agent who processes, publishes, and manages knowledge on a regular basis. Evaluation on social media is a nonlinear process, formative, conscious, and continuous that is accompanied by the elimination of standard rankings and tests. Conclusion: Based on the research results, it is suggested that those in charge of education use the coordinates of social network-based curriculum elements to design a curriculum based on social networks. For further research it is suggested that researchers implement the findings in an experimental environment to take a positive step towards the optimal use of social networks to learners’ learning outcome.   ===================================================================================== COPYRIGHTS  ©2020 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.  ====================================================================================

    Effects of quercetin supplementation on glycemic control among patients with metabolic syndrome and related disorders: A systematic review and meta-analysis of randomized controlled trials

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    This systematic review and meta-analysis of randomized controlled trials was performed to determine the effect of quercetin supplementation on glycemic control among patients with metabolic syndrome and related disorders. Databases including PubMed, MEDLINE, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials were searched until August 30, 2018. Nine studies with 10 effect sizes out of 357 selected reports were identified eligible to be included in current meta-analysis. The pooled findings indicated that quercetin supplementation did not affect fasting plasma glucose (FPG), homeostasis model of assessment-estimated insulin resistance, and hemoglobin A1c levels. In subgroup analysis, quercetin supplementation significantly reduced FPG in studies with a duration of �8 weeks (weighted mean difference WMD: �0.94; 95% confidence interval CI; �1.81, �0.07) and used quercetin in dosages of �500 mg/day (WMD: �1.08; 95% CI �2.08, �0.07). In addition, subgroup analysis revealed a significant reduction in insulin concentrations following supplementation with quercetin in studies that enrolled individuals aged <45 years (WMD: �1.36; 95% CI �1.76, �0.97) and that used quercetin in dosages of �500 mg/day (WMD: �1.57; 95% CI �1.98, �1.16). In summary, subgroup analysis based on duration of �8 weeks and used quercetin in dosages of �500 mg/day significantly reduced FPG levels. © 2019 John Wiley & Sons, Ltd

    PKD2 mutation in an Iranian autosomal dominant polycystic kidney disease family with misleading linkage analysis data

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    Background Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic renal disorder caused by mutation in 2 genes PKD1 and PKD2. Thus far, no mutation is identified in approximately 10 of ADPKD families, which can suggest further locus heterogeneity. Owing to the complexity of direct mutation detection, linkage analysis can initially identify the responsible gene in appropriate affected families. Here, we evaluated an Iranian ADPKD family apparently unlinked to both PKD1 and PKD2 genes. This is one of the pioneer studies in genetic analysis of ADPKD in Iranian population. Methods Linkage reanalysis was performed by regenotyping of flanking microsatellite markers in 8 individuals of the ADPKD family. Direct mutation analysis was performed by Sanger sequencing. Results Mutation analysis revealed a pathogenic mutation (c.1094+1G>A) in the PKD2 gene in the proband. Analyzing 2 healthy and 4 clinically affected members confirmed the correct segregation of the mutation within the family and also ruled out the disease in 1 suspected individual. Misinterpretation of the linkage data was due to the occurrence of 1 crossing over between the PKD2 intragenic and the nearest downstream marker (D4S2929). Homozygosity of upstream markers caused the recombination indistinguishable. Conclusion Although analysis of additive informative polymorphic markers can overcome the misleading haplotype data, it is limited because of the lack of other highly polymorphic microsatellite markers closer to the gene. Direct mutation screening can identify the causative mutation in the apparently unlinked pedigree; moreover, it is the only approach to achieve the confirmed diagnosis in individuals with equivocal imaging results. © 2016. The Korean Society of Nephrology. Published by Elsevier

    Postchemotherapy retroperitoneal lymph node dissection in patients with nonseminomatous testicular cancer: A single center experiences

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    Background: Testicular cancer accounts for about 1 - 1.5 of all malignancies in men. Radical orchiectomy is curative in 75 of patients with stage I disease, but advance stage with retroperitoneal lymph node involvement needs chemotherapy. All patients who have residual masses � 1 cm after chemotherapy should undergo postchemotherapy retroperitoneal lymph node dissection (PC-RPLND). Objectives: Treatment of advanced nonseminomatous testicular cancer is usually a combination of chemotherapy and surgery. We described our experience about postchemotherapy retroperitoneal lymph node dissection (PC-RPLND) in our center. Patients and Methods: In a retrospective cross-sectional study between 2006 and 2011, patients with a history of postchemotherapy retroperitoneal lymph node dissection (PC-RPLND) in Imam Khomeini hospital were evaluated. All patients had normal postchemotherapy serum tumor markers and primary nonseminomatous cancer. We reviewed retrospectively clinical, pathological, and surgical parameters associated with PC-RPLND in our center. Results: Twenty-one patients underwent bilateral PC-RPLND. Mean age was 26.3 years (ranged 16 - 47). Mean size of retroperitoneal mass after chemotherapy was 7.6 cm. Mean operative time was 198 minutes (120 - 246 minutes). Mean follow-up time was 38.6 months. Pathologic review showed presence of fibrosis/necrosis, viable germ cell tumor and teratoma in 8 (38.1), 10 (47.6) and 3 (14.28) patients, respectively. One patient in postoperative period of surgery and three patients in two first years after surgery were expired. Of 17 alive patients, only two (11.8) had not retrograde ejaculation. Conclusions: PC-RPLND is one the major operations in the field of urology, which is associated with significant adjunctive surgeries. In appropriate cases, PC-RPLND was associated with good cancer specific survival in tertiary oncology center. © 2015, Nephrology and Urology Research Center

    Effects of melatonin supplementation on hormonal, inflammatory, genetic, and oxidative stress parameters in women with polycystic ovary syndrome

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    Purpose: The aim of the current study was to evaluate the effect of melatonin administration on clinical, hormonal, inflammatory, and genetic parameters in women with polycystic ovarian syndrome (PCOS). Methods: The present randomized, double-blinded, placebo-controlled clinical trial was conducted among 56 patients with PCOS, aged 18�40 years old. Subjects were randomly allocated to take either 5 mg melatonin supplements (n = 28) or placebo (n = 28) twice a day for 12 weeks. Results: Melatonin administration significantly reduced hirsutism (β �0.47; 95 CI, �0.86, �0.09; P = 0.01), serum total testosterone (β �0.11 ng/mL; 95 CI, �0.21, �0.02; P = 0.01), high-sensitivity C-reactive protein (hs-CRP) (β �0.61 mg/L; 95 CI, �0.95, �0.26; P = 0.001), and plasma malondialdehyde (MDA) levels (β �0.25 μmol/L; 95 CI, �0.38, �0.11; P < 0.001), and significantly increased plasma total antioxidant capacity (TAC) levels (β 106.07 mmol/L; 95 CI, 62.87, 149.28; P < 0.001) and total glutathione (GSH) (β 81.05 μmol/L; 95 CI, 36.08, 126.03; P = 0.001) compared with the placebo. Moreover, melatonin supplementation downregulated gene expression of interleukin-1 (IL-1) (P = 0.03) and tumor necrosis factor alpha (TNF-α) (P = 0.01) compared with the placebo. Conclusions: Overall, melatonin administration for 12 weeks to women with PCOS significantly reduced hirsutism, total testosterone, hs-CRP, and MDA, while increasing TAC and GSH levels. In addition, melatonin administration reduced gene expression of IL-1 and TNF-α. Copyright © 2019 Jamilian, Foroozanfard, Mirhosseini, Kavossian, Aghadavod, Bahmani, Ostadmohammadi, Kia, Eftekhar, Ayati, Mahdavinia and Asemi

    The Effect of Cell Death on the Stability of a Growing Biofilm

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    In this paper, we investigate the role of cell death in promoting pattern formation within bacterial biofilms. To do this we utilise an extension of the model proposed by Dockery and Klapper [13], and consider the effects of two distinct death rates. Equations describing the evolution of a moving biofilm interface are derived, and properties of steady state solutions are examined. In particular, a comparison of the planar behaviour of the biofilm interface in the different cases of cell death is investigated. Linear stability analysis is carried out at steady state solutions of the interface, and it is shown that, under certain conditions, instabilities may arise. Analysis determines that, while the emergence of patterns is a possibility in `deep’ biofilms, it is unlikely that pattern formation will arise in `shallow’ biofilms
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