1,493 research outputs found
Evolution of 2D Truss Structures using Topology Optimization Technique with Meshless Method
p. 1058-1065Particle Swarm Optimization (PSO) is a new paradigm of Swarm Intelligence which is
inspired by concepts from 'Social Psychology' and 'Artificial Life'. Essentially, PSO
proposes that the co-operation of individuals promotes the evolution of the swarm. In terms of optimization, the hope would be to enhance the swarm's ability to search on a global scale so as to determine the global optimum in a fitness landscape. It has been empirically shown to perform well with regard to many different kinds of optimization problems. PSO is particularly a preferable candidate to solve highly nonlinear, non-convex and even discontinuous problems. In this paper, one enhanced version of PSO: Modified Lbest based PSO (LPSO) is proposed and applied to one of the most challenging fields of optimization -- truss topological optimization. Through a benchmark test and a spatial structural example, LPSO exhibited competitive performance due to improved global searching ability.Bae, J.; Lee, S.; Lee, C. (2009). Evolution of 2D Truss Structures using Topology Optimization Technique with Meshless Method. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/676
Orphan nuclear receptor Nurr1 induces neuron differentiation from embryonic cortical precursor cells via an extrinsic paracrine mechanism
AbstractNurr1 is an orphan nuclear receptor-type transcription factor (TF) that plays critical roles in midbrain dopamine neuron development. This study demonstrated a novel role for Nurr1 in neuronal/astrocytic differentiation of neural precursor (NP) cells isolated from rat embryonic cortices: overexpression of this TF promoted NP cell differentiation towards neurons at the expense of astrocytic differentiation. Single cell-based lineage analyses and experiments using co-cultures revealed that Nurr1 elicited its neurogenic role in an extrinsic paracrine manner. We defined diffusible factors and downstream neurogenic TFs responsible for the Nurr1-mediated neuronal differentiation
High-Performance PVC Gel for Adaptive Micro-Lenses with Variable Focal Length.
This paper presents a bio-inspired adaptive micro-lens with electrically tunable focus made of non-ionic high-molecular-weight polyvinyl chloride (PVC) gel. The optical device mimics the design of the crystalline lens and ciliary muscle of the human eye. It consists of a plano-convex PVC gel micro-lens on Indium Tin Oxide (ITO) glass, confined with an annular electrode operating as an artificial ciliary muscle. Upon electrical activation, the electroactive adhesive force of the PVC gel is exerted on the annular anode electrode, which reduces the sagittal height of the plano-convex PVC gel lens, resulting in focal length variation of the micro-lens. The focal length increases from 3.8 mm to 22.3 mm as the applied field is varied from 200 V/mm to 800 V/mm, comparable to that of the human lens. The device combines excellent optical characteristics with structural simplicity, fast response speed, silent operation, and low power consumption. The results show the PVC gel micro-lens is expected to open up new perspectives on practical tunable optics
Evaluation of protective effect of cyclodextrin glucanotransferase-treated Gastrodia elata Blume extract on ultraviolet B-induced premature skin aging
Purpose: To investigate the protective effect of Gastrodia elata Blume (G. elata, GE) and cyclodextrin glucanotransferase (CGTase) enzyme-treated G. elata extract (EGE) against premature skin aging using ultraviolet B (UVB)-exposed normal human dermal fibroblasts (NHDFs).Methods: The extract was characterized by liquid chromatography with tandem mass spectrometry (LC-MS/MS), ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC–QToF–MS) and nuclear magnetic resonance spectroscopy (NMR). The expression of matrix metalloproteinases (MMP-1,3), interleukin-6 (IL-6), transforming growth factor (TGF-β1) and procollagen type I was assayed using ELISA kits. Safety evaluation of EGE’s dietary administration and topical application was performed by in vivo acute oral toxicity and local lymph node tests.Results: Lower MMP-1 and IL-6 and higher procollagen type I and TGF-β1 levels were observed after treatment with EGE than with GE, indicating that EGE was more effective than GE in treating UVBinduced photoaging. With respect to phenolic composition, EGE had lower 4-hydroxybenzaldehyde (4- HBA) level and higher α-gastrodin level than GE. In UVB-irradiated NHDFs, α-gastrodin exhibited higher anti-aging activity than 4-HBA and β-gastrodin based on the expression of MMP-1, MMP-3, and procollagen type I. The in vivo data indicate that EGE was safe at concentrations of up to 2000 mg/kg for dietary administration and 0.1 % for topical application.Conclusion: EGE protects UVB-induced photoaged human skin better than GE owing to its higher α- gastrodin content. Thus, EGE may be potentially useful agent in anti-aging cosmetic products.Keywords: Gastrodia elata, α-Gastrodin, Anti-aging, CGTase, Ultraviolet B (UVB) irradiation, Matrix metalloproteinase, Procollagen, Normal human dermal fibroblast
Intravenous Vitamin C administration reduces fatigue in office workers: a double-blind randomized controlled trial
<p>Abstract</p> <p>Background</p> <p>Studies of the efficacy of vitamin C treatment for fatigue have yielded inconsistent results. One of the reasons for this inconsistency could be the difference in delivery routes. Therefore, we planned a clinical trial with intravenous vitamin C administration.</p> <p>Methods</p> <p>We evaluated the effect of intravenous vitamin C on fatigue in office workers. A group of 141 healthy volunteers, aged 20 to 49 years participated in this randomized, double-blind, controlled clinical trial. The trial group received 10 grams of vitamin C with normal saline intravenously, while the placebo group received normal saline only. Since vitamin C is a well-known antioxidant, oxidative stress was measured. Fatigue score, oxidative stress, and plasma vitamin C levels were measured before intervention, and again two hours and one day after intervention. Adverse events were monitored.</p> <p>Results</p> <p>The fatigue scores measured at two hours after intervention and one day after intervention were significantly different between the two groups (p = 0.004); fatigue scores decreased in the vitamin C group after two hours and remained lower for one day. Trial also led to higher plasma vitamin C levels and lower oxidative stress compared to the placebo group (p < 0.001, p < 0.001, respectively). When data analysis was refined by dividing each group into high-baseline and low-baseline subgroups, it was observed that fatigue was reduced in the lower baseline vitamin C level group after two hours and after one day (p = 0.004). The same did not hold for the higher baseline group (p = 0.206).</p> <p>Conclusion</p> <p>Thus, intravenous vitamin C reduced fatigue at two hours, and the effect persisted for one day. There were no significant differences in adverse events between two groups. High dose intravenous vitamin C proved to be safe and effective against fatigue in this study.</p> <p>Trial Registration</p> <p>The clinical trial registration of this trial is <url>http://ClinicalTrials.gov</url><a href="http://www.clinicaltrials.gov/ct2/show/NCT00633581">NCT00633581</a>.</p
Infantile Marfan syndrome in a Korean tertiary referral center
PurposeInfantile Marfan syndrome (MFS) is a rare congenital inheritable connective tissue disorder with poor prognosis. This study aimed to evaluate the cardiovascular manifestations and overall prognosis of infantile MFS diagnosed in a tertiary referral center in Korea.MethodsEight patients diagnosed with infantile MFS between 2004 and 2014 were retrospectively evaluated.ResultsTheir median age at the time of diagnosis was 2.5 months (range, 0–20 months). The median follow-up period was 25.5 months (range, 0–94 months). The median length at birth was 50.0 cm (range, 48–53 cm); however, height became more prominent over time, and the patients were taller than the 97th percentile at the time of the study. None of the patients had any relevant family history. Four of the 5 patients who underwent DNA sequencing had a fibrillin 1 gene mutation. All the patients with echocardiographic data of the aortic root had a z score of >2. All had mitral and tricuspid valve prolapse, and various degrees of mitral and tricuspid regurgitation. Five patients underwent open-heart surgery, including mitral valve replacement, of whom two required multiple operations. The median age at mitral valve replacement was 28.5 months (range, 5–69 months). Seven patients showed congestive heart failure before surgery or during follow-up, and required multiple anti-heart failure medications. Four patients died of heart failure at a median age of 12 months.ConclusionThe prognosis of infantile MFS is poor; thus, early diagnosis and timely cautious treatment are essential to prevent further morbidity and mortality
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