430 research outputs found
Numerical simulation of heat transfer to separation tio(2)/water nanofluids flow in an asymmetric abrupt expansion
Flow separation and reattachment of 0.2% TiO2 nanofluid in an asymmetric abrupt expansion is studied in this paper. Such flows occur in various engineering and heat transfer applications. Computational fluid dynamics package (FLUENT) is used to investigate turbulent nanofluid flow in the horizontal double-tube heat exchanger. The meshing of this model consists of 43383 nodes and 74891 elements. Only a quarter of the annular pipe is developed and simulated as it has symmetrical geometry. Standard k-epsilon second order implicit, pressure based-solver equation is applied. Reynolds numbers between 17050 and 44545, step height ratio of 1 and 1.82 and constant heat flux of 49050 W/m2 was utilized in the simulation. Water was used as a working fluid to benchmark the study of the heat transfer enhancement in this case. Numerical simulation results show that the increase in the Reynolds number increases the heat transfer coefficient and Nusselt number of the flowing fluid. Moreover, the surface temperature will drop to its lowest value after the expansion and then gradually increase along the pipe. Finally, the chaotic movement and higher thermal conductivity of the TiO2 nanoparticles have contributed to the overall heat transfer enhancement of the nanofluid compare to the water
Cost-effectiveness of age-related macular degeneration study supplements in the UK: combined trial and real-world outcomes data
Aims To evaluate the cost-effectiveness of Age-Related Eye Disease Study (AREDS) 1 & 2 supplements in patients with either bilateral intermediate age-related macular degeneration, AREDS category 3, or unilateral neovascular age-related macular degeneration AMD (nAMD), AREDS category 4.
Methods A patient-level health state transition model based on levels of visual acuity in the better-seeing eye was constructed to simulate the costs and consequences of patients taking AREDS vitamin supplements. Setting: UK National Health Service (NHS). The model was populated with data from AREDS and real-world outcomes and resource use from a prospective multicentre national nAMD database study containing 92 976 ranibizumab treatment episodes.
Interventions Two treatment approaches were compared: immediate intervention with AREDS supplements or no supplements. Main outcome measures: quality-adjusted life years (QALYs) and healthcare costs were accrued for each strategy, and incremental costs and QALYs were calculated for the lifetime of the patient. One-way and probabilistic sensitivity analyses were employed to test the uncertainty of the model.
Results For AREDS category 3, the incremental cost-effectiveness ratio was £30 197. For AREDS category 4 compared with no intervention, AREDS supplements are more effective (10.59 vs 10.43 QALYs) and less costly (£52 074 vs 54 900) over the lifetime of the patient.
Conclusions The recommendation to publicly fund AREDS supplements to category 3 patients would depend on the healthcare system willingness to pay. In contrast, initiating AREDS supplements in AREDS category 4 patients is both cost saving and more effective than no supplement use and should therefore be considered in public health policy
Increase in Convective Heat Transfer over A Backward-Facing Step Immersed in A Water-Based Tio2 Nanofluid
Investigation of flow separation and reattachment of 0.2% water-based TiO2 nanofluid in an annular suddenly expanding pipe is presented in this paper. Such flows occur in various engineering and heat transfer applications. A computational fluid dynamics package (FLUENT) is used to study turbulent nanofluid flow in this research. Only a quarter of an annular pipe was investigated and simulated because of its symmetrical geometry. Standard k–ε second-order implicit, pressure based-solver equations are applied. Reynolds numbers between 17,050 and 44,545, step height ratio of 1.82, and a constant heat flux of 49,050 W/m2 were utilized in simulation. The numerical simulation results show that increase in the Reynolds number leads to an increase of the heat transfer coefficient and of the Nusselt number. Moreover, the surface temperature dropped to its lowest value after the expansion and then gradually increased along the pipe. Finally, the chaotic movement and high thermal conductivity of the TiO2 nanoparticles have contributed to the overall heat transfer enhancement of the nanofluid
Lasp-1 Regulates Podosome Function
Eukaryotic cells form a variety of adhesive structures to connect with their environment and to regulate cell motility. In contrast to classical focal adhesions, podosomes, highly dynamic structures of different cell types, are actively engaged in matrix remodelling and degradation. Podosomes are composed of an actin-rich core region surrounded by a ring-like structure containing signalling molecules, motor proteins as well as cytoskeleton-associated proteins
Probabilistic Guarded P Systems, A New Formal Modelling Framework
Multienvironment P systems constitute a general, formal
framework for modelling the dynamics of population biology, which consists
of two main approaches: stochastic and probabilistic. The framework
has been successfully used to model biologic systems at both micro (e.g.
bacteria colony) and macro (e.g. real ecosystems) levels, respectively.
In this paper, we extend the general framework in order to include
a new case study related to P. Oleracea species. The extension is made
by a new variant within the probabilistic approach, called Probabilistic
Guarded P systems (in short, PGP systems). We provide a formal definition,
a simulation algorithm to capture the dynamics, and a survey of
the associated software.Ministerio de EconomÃa y Competitividad TIN2012- 37434Junta de AndalucÃa P08-TIC-0420
Simulation of heat transfer to separation Air flow in a concentric pipe
Flow separations occur in various engineering applications. Computational simulation by using standard k-ε turbulence model was performed to investigate numerically the characteristic of backward-facing step flow in a concentric configuration. This research is focused on the variation of Reynolds number, heat flux and step height in a fully developed turbulent air flow. The design consists of entrance tube, inner and outer tubes at the test section. The inner tube is placed along the entrance tube at the test section with an outer tube to form annular conduit. The entrance tube diameter was varied to create step height, s of 18.5 mm. The Reynolds number was set between 17050 and 44545 and heat flux was set between 719 W/m2 and 2098 W/m2 respectively. It is observed that the higher Reynolds number with step flow contribute to the enhancement of heat transfer. The reattachment point for q=719 W/m2 is observed at 0.542 m, which is the minimum surface temperature. The experimental data shows slightly lower distribution of surface temperature compared to simulation data. As for the same case in experimental result, the minimum surface temperature is obtained at 0.55 m. The difference between numerical and experimental result is 0.008 m. Finally, it can be inferred that utilizing the computational fluid dynamic package software, agreeable results could be obtained for the present research.
Keywords: Numerical Simulation; Heat Transfer; Turbulent Flow; Computational Fluid Dynamics; Backward Facing Ste
Nuclear localization and cytosolic overexpression of LASP-1 correlates with tumor size and nodal-positivity of human breast carcinoma
<p>Abstract</p> <p>Background</p> <p>LIM and SH3 protein 1 (LASP-1), initially identified from human breast cancer, is a specific focal adhesion protein involved in cell proliferation and migration, which was reported to be overexpressed in 8–12 % of human breast cancers and thought to be exclusively located in cytoplasm.</p> <p>Methods</p> <p>In the present work we analyzed the cellular and histological expression pattern of LASP-1 and its involvement in biological behavior of human breast cancer through correlation with standard clinicopathological parameters and expression of c-erbB2 (HER-2/neu), estrogen- (ER) and progesterone-receptors (PR). For this purpose immunohistochemical staining intensity and percentage of stained cells were semi-quantitatively rated to define a LASP-1 immunoreactive score (LASP-1-IRS). LASP-1-IRS was determined in 83 cases of invasive ductal breast carcinomas, 25 ductal carcinomas in situ (DCIS) and 18 fibroadenomas. Cellular LASP-1 distribution and expression pattern was visualized by immunofluorescence and confocal microscopy and assessed through separate Western blots of nuclear and cytosol preparations of BT-20, MCF-7, MDA-MB231, and ZR-75/1 breast cancer cells.</p> <p>Results</p> <p>Statistical analysis revealed that the resulting LASP-1-IRS was significantly higher in invasive carcinomas compared to fibroadenomas (p = 0.0176). Strong cytoplasmatic expression of LASP-1 was detected in 55.4 % of the invasive carcinomas, which correlated significantly with nuclear LASP-1-positivity (p = 0.0014), increased tumor size (p = 0.0159) and rate of nodal-positivity (p = 0.0066). However, levels of LASP-1 expression did not correlate with average age at time point of diagnosis, histological tumor grading, c-erbB2-, ER- or PR-expression.</p> <p>Increased nuclear localization and cytosolic expression of LASP-1 was found in breast cancer with higher tumor stage as well as in rapidly proliferating epidermal basal cells. Confocal microscopy and separate Western blots of cytosolic and nuclear preparations confirmed nuclear localization of LASP-1.</p> <p>Conclusion</p> <p>The current data provide evidence that LASP-1 is not exclusively a cytosolic protein, but is also detectable within the nucleus. Increased expression of LASP-1 in vivo is present in breast carcinomas with higher tumor stage and therefore may be related with worse prognosis concerning patients' overall survival.</p
A Real-Time Quantitative Analysis of Atmospheric Contributions of Hydrogen to Weld Arc Plasmas
Hydrogen contamination of weldments, particularly in the welded joints of high strength steels, can cause significant reductions in weld integrity, often resulting in failure of the joint. Inspection and repair of hydrogen assisted cracks in weldments is both costly and time consuming, thus real-time methods of detecting hydrogen levels during welding are essential. Analytical emission spectroscopy is a promising method of weld analysis, providing quantitative information in real time about the amount of hydrogen in the arc atmosphere
Use of flucinolone acetonide for patients with diabetic macular oedema:patient selection criteria and early outcomes in real world setting
Introduction: Fluocinolone acetonide slow release implant (Iluvien®) was approved in December 2013 in UK for treatment of eyes which are pseudophakic with DMO that is unresponsive to other available therapies. This approval was based on evidence from FAME trials which were conducted at a time when ranibizumab was not available. There is a paucity of data on implementation of guidance on selecting patients for this treatment modality and also on the real world outcome of fluocinolone therapy especially in those patients that have been unresponsive to ranibizumab therapy. Method: Retrospective study of consecutive patients treated with fluocinolone between January and August 2014 at three sites were included to evaluate selection criteria used, baseline characteristics and clinical outcomes at 3-month time point. Results: Twenty two pseudophakic eyes of 22 consecutive patients were included. Majority of patients had prior therapy with multiple intravitreal anti-VEGF injections. Four eyes had controlled glaucoma. At baseline mean VA and CRT were 50.7 letters and 631 μm respectively. After 3 months, 18 patients had improved CRT of which 15 of them also had improved VA. No adverse effects were noted. One additional patient required IOP lowering medication. Despite being unresponsive to multiple prior therapies including laser and anti-VEGF injections, switching to fluocinolone achieved treatment benefit. Conclusion: The patient level selection criteria proposed by NICE guidance on fluocinolone appeared to be implemented. This data from this study provides new evidence on early outcomes following fluocinolone therapy in eyes with DMO which had not responded to laser and other intravitreal agents
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