Search

Vapor chambers developed for high-heat-flux operation require advanced evaporator wick designs that can sustain capillary flow when boiling occurs over the heater region. A two-layer evaporator wick inte- grates a thin base wick layer that is supplied with liquid from a thick cap layer through an array of ver- tical feeding posts distributed over the heated area. This design allows boiling to occur within the thin base layer, while separating the incoming liquid feeding and outgoing vapor venting pathways. In our prior work, boiling in two-layer wicks was experimentally demonstrated to provide high-heat-flux dissi- pation over larger heater areas and at low thermal resistance. The current study experimentally explores the effect of two-layer wick design parameters, specifically the dimensions that alter the area available for liquid feeding and vapor venting, on the thermal performance and dryout limit of the wick, using water as the working fluid. Four different two-layer wick designs are fabricated over a 1 cm 2 evaporator area by sintering 180–212 μm copper particles. Increasing the vapor-venting area from 7% to 16% of the total evaporator area yielded a significant increase in the dryout limit, from 315 W/cm 2 to 405 W/cm 2 . Increasing the liquid-feeding area using wider posts increased the dryout limit further. Finally, a paramet- rically optimized design with fewer but larger posts and vents resulted in better performance compared to a design with denser features. With this two-layer wick design, we demonstrate an extremely high dryout limit of 512 W/cm 2 over the large 1 cm 2 heated area at a thermal resistance of 0.08 K/W.

A two-layer sintered porous evaporator wick for use in vapor chambers is shown to offer very high performance in passive high-heat-flux dissipation over large areas at a low thermal resistance. The two-layer wick has an upper cap layer dedicated to capillary liquid feeding of a thin base layer below that supports boiling. An array of vertical posts bridges these two layers for liquid feeding, while vents in the cap layer provide an unimpeded pathway for vapor removal from the base wick. The two-layer wick is fabricated using a combination of sintering and laser machining processes. The thermal resistance of the wicks during boiling is characterized in a saturated environment that replicates the capillary-fed working conditions of a vapor chamber evaporator. Thermal characterization tests are first performed using conventional single-layer evaporator wicks to analyze the effect of sintered particle size on capillaryfed boiling of water. Of the particle size ranges tested, wicks sintered from 180 to 212 micrometer-diameter particles provided the best combination of high dryout heat flux and a low boiling resistance. A two-layer evaporator wick comprising particles of this optimal size and a 15 x 15 array of liquid feeding posts yielded a maximum heat flux dissipation of 485 W/cm2 over a 1 cm2 heat input area while also maintaining a low thermal resistance of only ~0.052 K/W. The thermal performance of the two-layer wick is compared against various hybrid and biporous evaporator wicks previously investigated in the literature. While previous wick designs are typically restricted to small areas and low power levels or high surface superheats when dissipating such heat fluxes, the unique area-scalability of the two-layer wick design allows it to achieve an unprecedented combination of high total power and low-thermal-resistance heat dissipation over larger areas than were previously possible.

Introduction: We investigated the effect of combining exercise training and treatment with an endocannabinoid receptor 1 inhibitor (Rimonabant) on atherosclerosis burden and composition. Methods: Forty-eight apolipoprotein E-deficient (ApoE-/-) mice were kept on a 16-week highfat diet. Mice were then placed on a normal diet and were randomized to the following groups with n=12 mice for 6 more weeks: 1) Control (Co)-no intervention; 2) Exercise (Ex)-exercise training on treadmill; 3) Rimonabant (Ri)-oral administration of rimonabant (10 mg/kg/day); or 4) RimonabantþExercise (RiEx)-combination of Ri and Ex groups treatment. At the end, all animals were sacrificed, and blood samples, as well as aortic root specimens, were obtained for histomorphometric analysis and quantification of the serum and plaque content of matrix metalloproteinases (MMPs). Results: The mean plaque area was significantly smaller (RiEx: 43.18 ±1.72%, Ri: 44.66 ± 3.1%, Ex: 49 ± 4.10%, Co: 70.43 ± 2.83%) in all active treatment groups relative to the Co group (p < 0.01). Conversely, the relative concentrations of collagen and elastin were increased significantly across all treatment groups compared to Co (p < 0.05). Immunohistochemical analysis revealed significantly reduced macrophage content within plaques after all interventions, with the most pronounced effect observed after combined treatment (RiEx: 9.4 ± 3.92%, Ri: 15 ± 2.45%, Ex: 19.78 ± 2.79%, Co: 34.25 ± 4.99%; p < 0.05). Within plaques, the TIMP-1 concentration was significantly upregulated in exercise-treated groups. MMP-3 and MMP-9 concentrations were equivalently decreased in all three active treatment groups compared to controls (p < 0.001). Discussion: Both exercise and rimonabant treatments induced plaque regression and promoted plaque stability. The combined treatment failed to show additive or synergistic benefits relative to either intervention alone. © 2016 Hellenic Society of Cardiology.

Computerized cognitive assessment has become a new trend in neuropsychology as, over the recent years, clinicians have recognized its advantages and several computerized tools have been produced worldwide. Automated test administration and scoring are time-saving and allow examiners to focus on the examinee's behavior during testing. Also, automation standardizes administration procedure, permits for more accurate recording of reaction time, and objectifies scoring. Furthermore its proven sensitivity to cognitive impairment and its applicability with concurrent brain imaging gives a great promise to the investigation of brain function. However various detrimental factors can influence the test results. This fact together with the lack of relative training can deter professionals from opting for this new technique. Another reason is the confusion than can ensue by the plethora of tests and their variations. The present study focused on the latest versions of seven frequently used computerized test batteries in an attempt to outline the cognitive spectrum covered by each one so as to aid clinicians in selecting the most appropriate battery for their purposes. © 2015 Published by Elsevier GmbH.

The effect of a variety of surface enhancements on the heat transfer achieved with an array of impinging jets is experimentally investigated using the dielectric fluid HFE-7100 at different volumetric flow rates. The performance of a 5x5 array of jets, each 0.75mm in diameter, is compared to that of a single 3.75mm diameter jet with the same total open orifice area, in single-and two-phase operation. Four different target copper surfaces are evaluated: a baseline smooth flat surface, a flat surface coated with a microporous layer, a surface with macroscale area enhancement (extended square pin–fins), and a hybrid surface on which the pin–fins are coated with the microporous layer; area-averaged heat transfer and pressure drop measurements are reported. The array of jets enhances the single-phase heat transfer coefficients by 1.13–1.29 times and extends the critical heat flux (CHF) on all surfaces compared to the single jet at the same volumetric flow rates. Additionally, the array greatly enhances the heat flux dissipation capability of the hybrid coated pin–fin surface, extending CHF by 1.89–2.33 times compared to the single jet on this surface, with a minimal increase in pressure drop. The jet array coupled with the hybrid enhancement dissipates a maximum heat flux of 205.8 W/cm2 (heat input of 1.33 kW) at a flow rate of 1800 ml/min (corresponding to a jet diameter-based Reynolds number of 7800) with a pressure drop incurred of only 10.9 kPa. Compared to the single jet impinging on the smooth flat surface, the array of jets on the coated pin–fin enhanced surface increased CHF by a factor of over four at all flow rates.

Bu çalışmada, Orta Karadeniz Geçit İklim Kuşağında bulunan Tokat yöresinde ikinci ürün silajlık mısır tarımında geleneksel toprak işleme yöntemi (kulaklı pulluk + kültüvatör + dişli tırmık) ve azaltılmış toprak işleme yöntemi (çizel + dişli tırmık) ile düze ve sırta ekim yöntemlerinin toprağın fiziksel özelliklerine, (toprak nem içeriği, hacim ağırlığı ve penetrasyon direnci), bitki çıkış (ortalama çimlenme süresi (OÇS), çimlenme oranı indeksi (ÇOİ) ve tarla filiz çıkış derecesi (TFÇD)) ve bitki gelişme parametreleri (bitki boyu, bitki sap çapı, yeşil ot ve kuru madde verimi) üzerine etkileri incelenmiştir. Nem içeriği, hacim ağırlığı ve penetrasyon değerleri, 0-10 cm derinlikte, % 24,39-% 25,42; 1,24-1,33 g/cm3 ve 0,58–1,18 MPa arasında değişirken, 10-20 cm derinlikte ise, % 25,65- % 25,95; 1,25–1,34 g/cm3; 0,95 – 1,60 MPa arasında değişmiştir. Bitkisel özellikler açısından, OÇS, ÇOİ ve TFÇD değerleri sırasıyla, 12,80-12,85 gün, 0,34–0,35 adet/m.gün ve % 86,11-88,61 arasında bulunmuştur. Bitki boyu, gövde çapı, yeşil ot ve kuru madde verimleri de sırasıyla 244,7-266,2 cm; 2,9-3,1 cm; 7525,9–7580,8 kg/da ve 1523,4–1534,4 kg/da arasında değişmektedir. Sonuç olarak, toprak nem, hacim ağırlığı ve penetrasyon değerleri, geleneksel yönteme göre, azaltılmış toprak işleme yönteminde daha yüksek, fakat sırta ekim yönteminde düze ekime göre daha düşük düzeyde bulunmuştur. Bitkisel özellikler açısından ÇOİ ve TFÇD değerleri, geleneksel toprak işleme ve düze ekim yöntemine göre azaltılmış toprak işleme ve sırta ekim yönteminde daha yüksek çıkmıştır. Bitki boyu, gövde çapı, yeşil ot ile kuru madde verimi değerleri açısından da, geleneksel toprak işleme ve düze ekim yöntemine göre azaltılmış toprak işleme ve sırta ekim yöntemi daha yüksek değerler vermiştir. Bu çalışmanın bir sonucu olarak azaltılmış toprak işleme ve sırta ekim yöntemleri ikinci ürün silajlık mısır üretiminde önerilebilir

Local single- and two-phase heat transfer distributions are measured under a confined impinging jet issuing from a cross-shaped orifice. Spatially resolved temperature maps and convection coefficients resulting from the impinging flow are obtained via infrared imaging of a thin-foil heat source. The cooling patterns in single- and two-phase operation are explained by an accompanying numerical investigation of the fluid flow issuing from the orifice; computed velocity magnitudes and turbulence intensities are presented. In single-phase operation, the coolest surface temperatures correspond to areas with high liquid velocities. High velocities and developing turbulence are also shown to increase convective heat transfer along the diagonal outflow directions from the impinging jet. During two-phase transport, boiling preferentially begins in regions of low velocity, providing enhanced heat transfer in the areas least affected by the impingement. The cross-shaped orifice achieves local heat transfer coefficients that exceed the stagnation-point value of a circular jet of equivalent open orifice area by up to 1.5 times, while resulting in an increased pressure drop only 1.1 times higher than that of the circular jet.

Physical exercise is the cornerstone of cardiovascular disease treatment. The present study investigated whether exercise training affects atherosclerotic plaque composition through the modification of inflammatoryrelated pathways in apolipoprotein E knockout (apoE-/-) mice with diabetic atherosclerosis. Forty-five male apoE-/mice were randomized into three equivalent (n=15) groups: control (CO), sedentary (SED), and exercise (EX). Diabetes was induced by streptozotocin administration. High-fat diet was administered to all groups for 12 weeks. Afterwards, CO mice were euthanatized, while the sedentary and exercise groups continued high-fat diet for 6 additional weeks. Exercising mice followed an exercise program on motorizedtreadmill (5 times/week, 60 min/session). Then, blood samples and atherosclerotic plaques in the aortic root were examined. A considerable (P

Introduction: Inflammation and neurohormonal activation are considered to be involved in the development of earlier and/or later complications in congenital heart disease patients, even after a successful repair of the lesion. It is not yet clarified what is the role of the therapeutic interventions in the occurrence of such a response and how it could be associated with possible postoperative complications. Aim: We sought to assess the inflammatory and neurohormonal response to transcatheter closure of secundum type atrial septal defects (ASD) over a six-month follow-up period. We also evaluated the association between the respective markers and catheterization data as well as echocardiographic measurements. Methods: Plasma concentrations of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), interleukin-10 (IL-10), N-terminal-proatrial natriuretic peptide (NT-proANP) and N-terminal-probrain natriuretic peptide (NT-proBNP) were assessed and echocardiographic measurements were performed in twenty-eight patients with atrial septal defect prior to, and at the first, second and sixth months post transcatheter closure. Thirty-three age-matched healthy volunteers were also enrolled. Results: IL-6 plasma levels, although higher preoperatively, [physical logarithm (ln) IL-6: 3.37. ±. 0.66 vs 2.92. ±. 0.44. pg/ml, . p=. 0.015], reached control levels postoperatively, at the end of the third month, whereas TNF-α and IL-10 were not influenced by the procedure. NT-proANP levels were elevated preoperatively compared to the control group (ln NT-proANP 3.78. ±. 0.572 vs 3.48. ±. 0.30, . p=. 0.031), with a further significant increase during the 1st month (ln NT-proANP 3.78. ±. 0.572 vs 4.2. ±. 0.42, . p=. 0.006), following the pattern of the left atrial volume enlargement, and remained high even 6. months after the procedure .On the other hand, the initially normal concentrations of NT-proBNP, after a transient significant increase during the first month postoperatively (ln NT-proBNP 3.56. ±. 0.94 vs 4.58. ±. 0.91, . p

Aim: To investigate the effects of exercise on atherosclerotic plaque composition, the concentration of matrix metalloproteinases (MMPs) in the atherosclerotic plaque and the systemic circulation. Methods: Ninety apolipoprotein E-deficient (apoE-/-) mice (45 male) were randomized to the following groups (n = 15 each): control male/female; sedentary male/female; exercise male/female. Mice were kept on a 16-week high-fat diet. Subsequently, the control groups were sacrificed, while the rest of the animals were placed on a normal diet for 6 more weeks. During the latter period, the exercise groups were trained daily on treadmill. At the end of the study, mice were euthanized, and blood samples as well as aortic root specimens were obtained. Results: Compared to control and sedentary animals, exercise training reduced atherosclerotic plaques (-30%; p < 0.01) and increased elastin and collagen content in both genders (p < 0.05). Body weight or lipid profile did not change significantly. Decreased macrophages and MMP-9 as well as increased tissue inhibitor of metalloproteinases 1 (TIMP-1) levels were observed in the atherosclerotic plaques of the exercise-treated groups (p < 0.05). Plasma concentrations of MMP-9 decreased, while plasma TIMP-1 levels increased in the exercise compared to control and sedentary groups (p < 0.05). Conclusions: Exercise training had a favorable effect on the size and composition of the atherosclerotic plaque in apoE-/- mice, associated with suppressed MMP activity. Copyright © 2011 S. Karger AG.

The acute toxicological effects of gasoline on blood cells, and liver functions of albino rats were investigated. The rats were intraperitoneally injected with gasoline at different dose levels and were observed within 24 hours for signs and symptoms of toxicity. From the pilot study, 35.0g/kg was obtained as the minimum dose of gasoline that caused 100% death (LD100). Furthermore, LD50 study gave 12.30g/kg as the dose of gasoline that caused 50% death in rats (median lethal dose). The symptoms observed included occurrence of pallor, sedation, respiratory distress, coma and death and they were dose-dependent. Death rate increased with increase in the concentration of gasoline. The results of the hematological parameters obtained showed decrease in the mean + SEM values with increase in doses of gasoline injection. The biochemical parameters obtained showed an increase in the ALT and AST levels from 0.00 to 35.0g/kg and a corresponding increase in the ALP level from 0.00 to 35.0g/kg, indicating a case of hepatotoxicity. Direct and total bilirubin were also increased with increase in the doses of gasoline. The results, of this study showed that exposure to gasoline is potentially toxic and the degree of toxicity may be influenced by the dose or concentration to which persons are exposed. Keywords: Albino Rat, Gasoline, Histopathology Journal of Medical Laboratory Science Vol. 13 (2) 2004: pp. 24-28