bluuebunny/crossref_metadata_2025 huggingface dataset:
Increased technetium uptake is not equivalent to muscle necrosis: scintigraphic, morphological and intramuscular pressure analyses of sore muscles after exercise
Authors: CRENSHAW A. G. , FRIDÉN J. , HARGENS A. R. , LANG G. H. , THORNELL L‐E.
Published: December 2008

A scintigraphic technique employing technetium pyrophosphate uptake was used to identify the area of skeletal muscle damage in the lower leg of four runners 24 h after an ultramarathon footrace (160 km). Most of the race had been run downhill which incorporated an extensive amount of eccentric work. Soreness was diffuse throughout the posterior region of the lower leg. In order to interpret what increased technetium uptake reflects and to express extreme endurance related damages, a biopsy was taken from the 3‐D position of abnormal uptake. In addition, intramuscular pressures were determined in the deep posterior compartment. Scintigraphs revealed increased technetium pyrophosphate uptake in the medial portion of the gastrocnemius muscle. For 3698 fibres analysed, 33 fibres (I%) were necrotic, while a few other fibres were either atrophic or irregular shaped. A cluster of necrotic fibres occurred at the fascicular periphery for one subject and fibre type grouping occurred for another. Ultrastructural analysis revealed Z‐line streaming near many capillaries and variously altered subsarcolemmal mitochondria including some with paracrystalline inclusions. The majority of the capillaries included thickened and irregular shaped endothelial cells. Intramuscular pressures of the deep posterior compartment were slightly elevated (12–15 mmHg) for three of the four subjects. Increased technetium uptake following extreme endurance running does not just reflect muscle necrosis but also subtle fibre abnormalities. Collectively, these pathological findings are attributed to relative ischaemia occurring during the race and during pre‐race training, whereas, intramuscular pressure elevations associated with muscle soreness are attributed to mechanical stress caused by extensive eccentric work during the race.
Prodromal contractions and contractility in the feline bladder
Authors: SATCHELL P. , WATSON E. , VAUGHAN C.
Published: December 2008

In the cat there are at least two distinct contractile states of the bladder during urine storage, one when prodromal contractions are present and one when non‐micturating contractions are present. It is proposed that prodromal contractions are myogenic. This proposition was examined by comparing prodromal contractions before and after hypogastric nerve section as well as comparing prodromal contractions with the contractions that remain after sectioning of the hypogastric nerves. Key contraction characteristics, such as amplitude, maximum gradient and the variance of the intercontraction interval were not significantly changed by hypogastric nerve section, providing volume effects were corrected for, which suggested that prodromal contractions have a myogenic origin.
Both somatostatin and insulin responses to glucose are impaired in the perfused pancreas of the spontaneously noninsulin‐dependent diabetic GK (Goto‐Kakizaki) rats
Authors: ABDEL‐HALIM S. M. , GUENIFI A. , EFENDIĆ S. , ÖSTENSON C.‐G.
Published: December 2008

We have studied the responses of insulin and somatostatin to glucose and arginine in the perfused pancreas of GK rats, which spontaneously develop mild noninsulin‐dependent diabetes without concomitant obesity. Our GK rats have been obtained after at least 42 generations of inbreeding of Wistar rats with initial selection for increased blood glucose levels during glucose tolerance tests. During perfusion with a high (16.7 mmol l‐1) glucose concentration, normal responses of insulin and somatostatin were found in pancreata from non‐diabetic control rats. In GK pancreata, however, these responses were virtually abolished. When the glucose concentration of the perfusion medium was switched from 16.7 to 3.3 mmol l‐1glucose, a transient increase –‘off‐response’– in both insulin and somatostatin secretion was noted in GK but not in control pancreata. During the subsequent stimulation with arginine (20 mmol l‐1), insulin and somatostatin responses were similar in pancreata from non‐diabetic and GK rats. The pancreatic content of insulin did not differ between non‐diabetic and GK rats, whereas the content of somatostatin was increased by 56% (P < 0.025) in GK glands. In conclusion, abnormalities assigned to pancreatic hormone secretion in the GK rat comprise not only markedly impaired insulin but also somatostatin response to glucose. Since there was no decrease in pancreatic content of these hormones in GK rats, the cause of glucose insensitivity of the hormone‐producing cells is likely to reside in a defective stimulus‐secretion coupling rather than decreased availability of the hormones.
Muscle fibre types and enzyme activities after training with local leg ischaemia in man
Authors: ESBJÖRNSSON M. , JANSSON E. , SUNDBERG C. J. , SYLVÉN C. , EIKEN O. , NYGREN A. , KAIJSER L.
Published: December 2008

Eight healthy men performed supine one‐legged training on a bicycle ergometer 45 min per leg four times per week for 4 week. The ergometer and lower body were inside a pressure chamber, the opening of which was sealed at the level of the crotch. One leg trained with impeded leg blood flow (I‐leg), induced by an increased (50 mmHg) chamber pressure, at the highest tolerable intensity. The contralateral leg trained at the same power under normal pressure (N‐leg). Before and after training biopsies were taken from the vastus lateralis of both legs and maximal one‐legged exercise tests were executed with both legs. Biopsies were repeated when the subjects had been back to their habitual physical activity for 3 months. Training increased exercise time to exhaustion, but more in the I‐leg than in the N‐leg. After training, the I‐leg had higher activity of citrate synthase (CS), a marker of oxidative capacity, and lower activity of the M‐subunit of lactate dehydrogenase isoenzymes. It also had a higher percentage of type‐I fibres and a lower percentage of IIB fibres, larger areas of all fibre types and a greater number of capillaries per fibre. It is concluded that ischaemic training changes the muscle metabolic profile in a direction facilitating aerobic metabolism. An altered fibre‐type composition may contribute, but is not enough prerequisite for the change.
Resting oxygen consumption in rats during food restriction, starvation and refeeding
Authors: MUNCH I. C. , MARKUSSEN N. H. , ÓRITSLAND N. A.
Published: December 2008

Oxygen consumption was measured in male rats during starvation and during different regimens of restricted feeding and refeeding after starvation. Changes in oxygen consumption and body mass were mostly parallel, but rats with a very reduced food intake displayed the same reduction in oxygen consumption as starved rats, despite the smaller reduction in body mass. Also, rats fed different amounts of food after starvation had different oxygen consumptions, but displayed the same changes in body mass. Two different refeeding regimens with restricted food amounts either induced a further depression of oxygen consumption (i.e. below starvation oxygen consumption), or a stabilizing of oxygen consumption on the level of starvation. The changes in oxygen consumption during restriction and feeding after starvation indicate that reductions in resting metabolic rate may not always be predicted from either body mass change or food intake.
Effects of hyperoxia on bronchial wall dimensions and lung mechanics in rats
Authors: MURCHIE P. , JOHNSTON P. W. , ROSS J. A. S. , GODDEN D. J.
Published: December 2008

The effects of exposure to hyperoxic conditions (> 95 kPa at normobaric pressure) on bronchial wall dimensions and lung mechanics were examined in adult rats. Measurements of baseline pulmonary resistance and changes in pulmonary resistance following acetylcholine aerosol inhalation were made in rats exposed to hyperoxia for 48 and 60 h and in control rats exposed to air. Exposures for 48 h were carried out in humid (80% relative humidity) or dry (35–40% relative humidity) conditions. Morphometric measurements of airway wall thickness in lobar bronchi were made in separate groups of similarly exposed rats. Exposure to hyperoxia was associated with an increase in baseline pulmonary resistance (control rats 0.043 (0.016) cmH2O ml‐1 s‐1, 60 h exposed rats 0.125 (0.042) cmH2O ml‐1 s‐1) but hyper‐responsiveness to acetylcholine inhalation did not occur. Thickness of the airway wall and its subdivisions, epithelium, lamina propria and muscularis, was not altered by hyperoxic exposure in humid conditions. However, epithelial thickening in the lobar bronchi was observed in rats exposed for 48 h to hyperoxia in dry conditions compared to rats exposed in humid conditions (mean (SD) thickness 13.2 (3.3) μm for controls, 14.5 (1.5) μm for humid exposed rats and 16.5 (3.3) μm for dry exposed rats). The increase in pulmonary resistance caused by hyperoxic exposure is unlikely to be due to airway damage as airway hyper‐responsiveness did not occur, and is more likely to be associated with the development of alveolar oedema. Environmental humidity may modulate lung damage induced by hyperoxia, as exposure in dry conditions was associated with significant epithelial thickening.
Changes in lower limb muscle cross‐sectional area and tissue fluid volume after transition from standing to supine
Authors: BERG H. E. , TEDNER B. , TESCH P. A.
Published: December 2008

Lower limbs show acute fluid shift in response to transition from upright to supine body position. It is hypothesized that this would affect tomographic estimations of muscle mass and composition. Seven healthy subjects were investigated during the initial 120 min of bed rest, using repeated computerized tomography (CT) and continuous bioelectrical impedance analysis (BIA). Thigh and calf muscle cross‐sectional area (CSA) decreased (P < 0.05) by 1.9 and 5.5% whereas fat CSA decreased (P < 0.05) by 4.1 and 4.4%, respectively. Radiological density (RD) of muscle showed a simultaneous increase (P < 0.05) by 4.8% in calf but not (P > 0.05) in thigh. No changes occurred (P > 0.05) in muscle or fat CSA or muscle RD in either thigh or calf between the first and second hour of bed rest. Fluid shift, as estimated by BIA, showed an exponential decay in thigh (τth = 30 min) and calf (τc2 = 37 min) by 2.5 and 8.7%, respectively, from first to 120 min of bed rest. Moreover, the calf showed an initial rapid (τc1 = 8 s) 2.2% decrease. The demonstrated short‐term changes in leg CSA were more pronounced in the calf than in the thigh. They were similar in muscle and subcutaneous fat. These fluid shifts merit consideration when tomographic imaging techniques are used to estimate muscle mass and composition.
Plasma oxytocin, prolactin, insulin and LH after 24 h of fasting and after refeeding in lactating sows
Authors: ROJKITTIKHUN T. , UVNÄS‐MOBERG K. , EINARSSON S.
Published: December 2008

The effects of 24 h of fasting and refeeding on the release of oxytocin, prolactin, insulin and LH in three lactating sows were investigated. The sows were starved, but supplied with water ad libitum, from 09.00 h on day 27 of lactation until 15.00 h on day 28 of lactation, when they were refed. Blood samples were collected continuously, using an automatic collection system, at a rate of 1 ml min‐1 from 09.00 to 21.00 h on day 28 (P1 = 6 h period after the 24 h fast, P2 = 6 h period after refeeding). For both P1 and P2 the mean number of nursings was 7.0 ± 1.0. Plasma insulin and glucose decreased to very low levels during fasting and increased (P < 0.001) after refeeding (insulin, 2.5 ± 0.7 vs. 28.9 ± 0.7 mU 1‐1; glucose, 2.6 ± 0.3 vs. 6.4 ± 0.3 mmol 1‐1). Following fasting, levels of prolactin were low (2.8 ± 0.1 μg 1‐1), and sucking did not induce significant release of prolactin. However, prolactin increased rapidly after refeeding (5.4 ± 0.1 μg 1‐1, P < 0.001). Neither the 24 h fast nor refeeding had a marked effect on basal levels of oxytocin, the percentage of sucklings with an oxytocin peak or the size of oxytocin peak. LH release (average and basal levels and number of pulses/6 h) during fasting was similar to that measured after refeeding. Plasma CCK increased significantly after feeding. The results indicate that the release of prolactin is also regulated by feed intake. Consequently the 24 h fast in lactating sows may alter milk production via an inhibition of prolactin release. Neither a stimulatory effect of insulin nor an inhibitory effect of prolactin on LH release was observed.
Immunohistochemical localization of peripheral nitric oxide synthase‐containing nerves using antibodies raised against synthesized C‐ and N‐terminal fragments of a cloned enzyme from rat brain
Authors: ALM P. , LARSSON B. , EKBLAD EVA , SUNDLER F. , ANDERSSON K.‐E.
Published: December 2008

Antibodies were raised in rabbits against C‐ or N‐terminal fragments of a cloned nitric oxide synthase (NOS) enzyme from rat cerebellum, and used for demonstration of NOS‐immunoreactive (NOS‐IR) nerves in different tissues from the rat (colon, duodenum, adrenal gland, aorta, caval vein, penis and urethra). Both antisera demonstrated the same neuronal elements, although with differences in intensity in the immunoreaction in some tissues. Sections incubated with antisera preabsorbed with excess of the antigens showed no NOS immunoreactivity. In duodenum and colon, NOS‐immunoreactivity was found in the cytoplasm of numerous cell bodies in myenteric ganglia and in some nerve cell bodies in the submucosa. NOS‐IR nerve fibres were numerous in the circular muscle layer, while few were found in the longitudinal layer or the mucosa and submucosa. In the penis, strong NOS immunoreactivity was found in nerves surrounding the deep penile and dorsal arteries, and in nerves in the stroma of the cavernous tissue. In the urethra, NOS immunoreactivity was found in nerves in the mucosa. No NOS immunoreactivity was found in the urothelium. The adrenal medulla, and occasionally the cortex, contained nerve cell bodies with strong cytoplasmic NOS immunoreactivity as well as scattered nerve fibres. No NOS immunoreactivity was found in the abdominal aorta or inferior caval vein. Combined NOS immunostaining and NADPH diaphorase staining showed that virtually all NOS‐IR nerve structures were also NADPH diaphorase‐positive. However, thin nerve fibres and cell linings were sometimes better visualized by NOS‐immunohistochemistry. Furthermore, the adrenal cortex, which only occasionally showed NOS immunoreactivity, was strongly NADPH diaphorase‐positive. A positive NADPH diaphorase reaction, but a negative NOS immunoreactivity, was also found in other structures, such as urothelium, epithelial cells in duodenum and colon, and endothelium of some vessels. It is concluded that the antibodies raised against the synthesized sequences of neuronal NOS are highly specific and may be used in immunohistochemistry in order to detect neuronal NOS.
A study of cholinergic and β‐adrenergic components in the regulation of blood flow in the tooth pulp and gingiva in man
Authors: AARS H. , BRODIN P. , ANDERSEN E.
Published: December 2008

In 10 subjects, laser Doppler flowmetry was used to study whether cholinergic or β‐adrenergic pathways are involved in the control of tooth pulp blood flow (PBF) in response to isometric hand grip and the cold pressor test. We also examined if differences exist between the regulation of blood flow in the tooth pulp and the nearby gingiva (GBF). Isometric hand grip (35% of maximum force, 2 min) and the subsequent ischaemia (2 min) induced a brief rise in PBF and a more long‐lasting rise in GBF. Atropine increased heart rate about by 40% and changed the pulpal response to a fall in flow, without altering gingival flow. Propranolol, causing a 20% reduction in heart rate, had no effect on either flow during the actual test, but induced a rise in GBF after the ischaemic period. The cold pressor test (2 min at 0.5 °C) resulted in a reduction in PBF and GBF, unaffected by the blocking drugs. With atropine, however, PBF increased immediately after this test. The relative changes in arterial pressure and heart rate were unaffected by the drugs. Our study has demonstrated the existence of cholinergic nervous vasodilation in vessels serving the tooth pulp. Non‐adrenergic non‐cholinergic mechanisms probably contribute to the evoked rise in GBF during exercise. β‐adrenoceptors are involved in the control of GBF immediately after isometric exercise. While the two tests under control conditions evoked mostly parallel changes in PBF and GBF, the use of blocking agents showed that blood flow is controlled by different mechanisms in the two adjacent vascular beds.
Non‐uniformity of two‐dimensional myocardial deformation in response to chronotropic and inotropic stimulation in cats
Authors: HEXEBERG E. , BIRKELAND S. , MATRE K.
Published: December 2008

The degree of uniformity of myocardial deformation for cross‐oriented segments in the anterior wall of the left ventricle is influenced both by loading conditions and by infusion of isoprenaline. The aim of this study was to clarify the chronotropic influence (atrial pacing) compared to the combined inotropic and chronotropic effects of isoprenaline on uniformity of contraction. In eight open‐chest pentobarbitone‐anaesthetized cats segment performance was measured by orthogonal sonomicrometry. Heart rate (HR) increased from control state, 199 ± 5 (mean ± SEM) beats min‐1, to 224 ± 6 and 227 ± 7 beats min‐1 during atrial pacing and isoprenaline infusion, respectively (P < 0.0005). Circumferential segment shortening remained unchanged during pacing but increased with isoprenaline (P < 0.0005). Longitudinal segments showed reduced shortening during pacing (P < 0.05), whereas shortening during isoprenaline infusion did not differ from control shortening. The ratio between shortening of longitudinal and circumferential segments, long/circ ratio, changed from 0.52 ± 0.13 in the control state to 0.36 ± 0.10 during pacing and 0.39 ± 0.11 with isoprenaline (P < 0.05). End‐systolic pressure‐length relations were unchanged by atrial pacing but showed leftward shifts during isoprenaline infusion. Myocardial tissue blood flow (microspheres) was unchanged during interventions. We conclude that both atrial pacing and isoprenaline infusion lead to a more non‐uniform deformation in the anterior wall. However, non‐uniformity during atrial pacing was primarily related to reduced longitudinal shortening whereas the non‐uniformity during isoprenaline infusion was due to increased circumferential shortening.
Regulation of early response genes in pancreatic acinar cells: external calcium and nuclear calcium signalling aspects
Authors: Fedirko N. , Gerasimenko J. V. , Tepikin A. V. , Gerasimenko O. V.
Published: December 2008

Nuclear calcium signalling has been an important topic of investigation for many years and some aspects have been the subject of debate. Our data from isolated nuclei suggest that the nuclear pore complexes (NPCs) are open even after depletion of the Ca2+ store in the nuclear envelope (NE). The NE contains ryanodine receptors (RyRs) and Ins(1,4,5)P3 receptors [Ins(1,4,5)P3Rs], most likely on both sides of the NE and these can be activated separately and independently: the RyRs by either NAADP or cADPR, and the Ins(1,4,5)P3Rs by Ins(1,4,5)P3. We have also investigated the possible consequences of nuclear calcium signals: the role of Ca2+ in the regulation of immediate early genes (IEG): c‐fos, c‐myc and c‐jun in pancreatic acinar cells. Stimulation with Ca2+‐mobilizing agonists induced significant increases in levels of expression. Cholecystokinin (CCK) (10 nm) evoked a substantial rise in the expression levels, highly dependent on external Ca2+: the IEG expression level was lowest in Ca2+‐free solution, increased at the physiological level of 1 mm [Ca2+]o and was maximal at 10 mm [Ca2+]o, i.e.: 102 ± 22% and 163 ± 15% for c‐fos; c‐myc −73 ± 13% and 106 ± 24%; c‐jun −49 ± 8% and 59 ± 9% at 1 and 10 mm of extracellular Ca2+ respectively. A low CCK concentration (10 pm) induced a small increase in expression. We conclude that extracellular Ca2+ together with nuclear Ca2+ signals induced by CCK play important roles in the induction of IEG expression.
A Near‐Infrared (NIR) Technique for Imaging Food Materials
Authors: Pallav P. , Diamond G.G. , Hutchins D.A. , Green R.J. , Gan T.H.
Published: December 2008

ABSTRACT: The results of imaging experiments in food materials are presented, using near‐infrared wavelengths. The technique uses a modulated source and a lock‐in amplifier detection circuit to give a high sensitivity to changes in through‐transmission signal levels. This is shown to lead to a set of images, whereby the internal content of various foods can be imaged. Examples are presented of the detection of foreign bodies, both metallic and nonmetallic, to illustrate the imaging performance.
Detection and Enumeration of Vibrio vulnificus by Direct Colony Immunoblot
Authors: Senevirathne R.N. , Janes M.E. , Simonson J.G.
Published: December 2008

ABSTRACT:  A direct colony immunoblot method (DCI) for the enumeration of Vibrio vulnificus was developed. Bacterial colonies were transferred from agar plates to membranes, which were then dried and blocked with bovine serum albumin. Subsequently, the membranes were treated with anti‐V. vulnificus H antibodies, washed and incubated with peroxidase‐conjugated goat anti‐rabbit IgG. After a final wash, the membranes were exposed to a substrate mixture containing H2O2 which resulted in the development of a purple color by V. vulnificus colonies. The DCI detected all clinical and environmental V. vulnificus strains tested and did not cross‐react with other Vibrio species including V. cholerae, V. parahaemolyticus, or V. fluvialis. The DCI was then compared to the DNA hybridization procedure (DNAH) using V. vulnificus agar plates inoculated with mixed cultures of V. vulnificus and V. parahaemolyticus and V. vulnificus‐seeded oyster homogenates. Both DCI and DNAH detected 1 to 2 log colony forming units (CFU)/mL V. vulnificus mixed with 4 log CFU/mL V. parahaemolyticus. Both methods were comparable and demonstrated no significant statistical differences when enumerating V. vulnificus in mixed cultures or in oyster homogenates seeded with levels of V. vulnificus from 2 to 6 log CFU/mL. The DCI demonstrated clearer color development and was less time consuming than the DNAH.
Antimicrobial Efficacy of Zinc Oxide Quantum Dots against Listeria monocytogenes, Salmonella Enteritidis, and Escherichia coli O157:H7
Authors: Jin T. , Sun D. , Su J.Y. , Zhang H. , Sue H.‐J.
Published: December 2008

ABSTRACT:  Zinc oxide quantum dots (ZnO QDs) are nanoparticles of purified powdered ZnO. These were evaluated for antimicrobial activity against Listeria monocytogenes, Salmonella Enteritidis, and Escherichia coli O157:H7. The ZnO QDs were utilized as a powder, bound in a polystyrene film (ZnO‐PS), or suspended in a polyvinylprolidone gel (ZnO‐PVP). Bacteria cultures were inoculated into culture media or liquid egg white (LEW) and incubated at 22 °C. The inhibitory efficacies of ZnO QDs against 3 pathogens were concentration dependent and also related to type of application. The ZnO‐PVP (3.2 mg ZnO/mL) treatment resulted in 5.3 log reduction of L. monocytogenes and 6.0 log reduction of E. coli O157:H7 in growth media after 48 h incubation, as compared to the controls. Listeria cells in the LEW control increased from 3.8 to 7.2 log CFU/mL during 8 d incubation, while the cells in the samples treated with 1.12 and 0.28 mg ZnO/mL were reduced to 1.4 and 3.0 log CFU/mL, respectively. After 8 d incubation, the cell populations of Salmonella in LEW in the presence of 1.12 and 0.28 mg ZnO/mL were reduced by 6.1 and 4.1 log CFU/mL over that of controls, respectively. ZnO powder and ZnO‐PVP showed significant antimicrobial activities against all 3 pathogens in growth media and LEW. ZnO‐PVP coating had less inhibitory effect than the direct addition of ZnO‐PVP. No antimicrobial activities of ZnO‐PS film were observed. This study suggested that the application of ZnO nanoparticles in food systems may be effective at inhibiting certain pathogens.
Chromatographic Isolation and Characterization of a Novel Peroxidase from Large Lima Legumes
Authors: Wang S.Y. , Gong Y.S. , Zhou J.J.
Published: December 2008

ABSTRACT:  A novel peroxidase with antifungal activity was isolated from the large lima bean (Phaseolus limensis) seeds. The procedure entailed extraction, ammonium sulfate precipitation, affinity chromatography on Affi‐gel blue gel, ion exchange chromatography on SP‐Toyopearl, and gel filtration on Sephadex G‐75. The enzyme was adsorbed on Affi‐gel blue gel and SP‐Toyopearl, and possessed a molecular weight of 34 kDa in SDS‐polyacrylamide gel electrophoresis under both reducing and nonreducing conditions. There was an almost 110‐fold increase in specific activity of the purified peroxidase compared with that of the crude extract. The enzyme exhibited a pI of 8.6 by isoelectric focusing electrophoresis, indicating that it is a basic protein. The optimum pH and the optimum temperature were 5.5 and 30 °C, respectively. The enzyme was stable up to 55 °C. It potently suppressed mycelial growth in Fusarium solani, Mycosphaerella arachidicola, and Pythium aphanidermatum with an IC50 of 76, 103, and 119 μM, respectively.
Improvement of Foaming Property of Egg White Protein by Phosphorylation through Dry‐Heating in the Presence of Pyrophosphate
Authors: Hayashi Y. , Nagano S. , Enomoto H. , Li C.‐P. , Sugimoto Y. , Ibrahim H.R. , Hatta H. , Takeda C. , Aoki T.
Published: December 2008

ABSTRACT:  Egg white protein (EWP) was phosphorylated by dry‐heating in the presence of pyrophosphate at pH 4 and 85 °C for 1 d, and the foaming properties of phosphorylated EWP (PP‐EWP) were investigated. The phosphorus content of EWP increased to 0.71% as a result of phosphorylation. To estimate the foaming properties of EWP, the foams were prepared by 2 methods: bubbling of the 0.1% (w/v) protein solution and whipping of the 10% (w/w) protein solution with an electric mixer. The foaming power, which was defined as an initial conductivity of foam from 0.1% (w/v) protein solution, was a little higher in PP‐EWP than in native EWP (N‐EWP), and the foaming stability of PP‐EWP was much higher than that of dry‐heated EWP (DH‐EWP) and N‐EWP. The microscopic observation of foams from the 10% (w/w) solution showed that the foams of PP‐EWP were finer and more uniform than those of N‐ and DH‐EWP. Although there were no significant differences in the specific gravity and overrun of the foams between PP‐ and DH‐EWP (P < 0.05), the specific gravity and overrun of the foams from PP‐EWP were smaller and higher, respectively, than that of the foams from N‐EWP. The drainage volume was smaller in the foams from PP‐EWP than in those from N‐ and DH‐EWP. These results demonstrated that phosphorylation of EWP by dry‐heating in the presence of pyrophosphate improved the foaming properties, and that it was more effective for the foam stability than for the foam formation.
Persistent Organic Pollutants in Fish Oil Supplements on the Canadian Market: Polychlorinated Biphenyls and Organochlorine Insecticides
Authors: Rawn Dorothea F.K. , Breakell K. , Verigin V. , Nicolidakis H. , Sit D. , Feeley M.
Published: December 2008

ABSTRACT:  Fish and seal oil dietary supplements, marketed to be rich in omega‐3 fatty acids, are frequently consumed by Canadians. Samples of these supplements (n = 30) were collected in Vancouver, Canada, between 2005 and 2007. All oil supplements were analyzed for polychlorinated biphenyls (PCBs) and organochlorine insecticides (OCs) and each sample was found to contain detectable residues. The highest ΣPCB and ΣDDT (1,1,1‐trichloro‐di‐(4‐chlorophenyl)ethane) concentrations (10400 ng/g and 3310 ng/g, respectively) were found in a shark oil sample while lowest levels were found in supplements prepared using mixed fish oils (anchovy, mackerel, and sardine) (0.711 ng ΣPCB/g and 0.189 ng ΣDDT/g). Mean ΣPCB concentrations in oil supplements were 34.5, 24.2, 25.1, 95.3, 12.0, 5260, 321, and 519 ng/g in unidentified fish, mixed fish containing no salmon, mixed fish with salmon, salmon, vegetable with mixed fish, shark, menhaden (n = 1), and seal (n = 1), respectively. Maximum concentrations of the other OCs were generally observed in the seal oil. The hexachlorinated PCB congeners were the dominant contributors to ΣPCB levels, while ΣDDT was the greatest contributor to organochlorine levels. Intake estimates were made using maximum dosages on manufacturers' labels and results varied widely due to the large difference in residue concentrations obtained. Average ΣPCB and ΣDDT intakes were calculated to be 736 ± 2840 ng/d and 304 ± 948 ng/d, respectively.
Impatiens yilingiana sp. nov. and I. huangyanensis subsp. attenuata subsp. nov. (Balsaminaceae) from Zhejiang, eastern China
Authors: Jin Xiao‐Feng , Yang Shu‐Zhen , Chen Zheng‐Hai , Qian Li
Published: December 2008

A new species and a new subspecies of Impatiens (Balsaminaceae) from Zhejiang, China, are described and illustrated. The new species Impatiens yilingiana is morphologically similar to I. noli‐tangere, but differs in having lateral sepals narrowly ovate, wings with a 4–5 mm long stipe at base, obliquely bi‐lobed at apex, wings and lip (lower sepal) without purple spots, and carinate dorsal costae of the standards. The new subspecies I. huangyanensis subsp. attenuata differs from the typical entity in having larger lateral sepals and lower sepals attenuately constricted to a spur. In addition, micromorphology of pollen grains and seed coat of the new taxa are compared with related taxa.
Micro-Fluidic Technologies for Blood Diagnostics
Authors: Chang Hsueh-Chia
Published: December 2008

There is considerable market interest for miniature blood diagnostic kits for cholesterol, ovulation, glucose, bacteria, leukemia cells, coagulation tests, drugs etc. However, the presence of blood cells in the blood samples introduces an array of micro-fluidic issues that have become main obstacles to commercialization of these products. We discuss some of these anomalous micro-fluidic features of blood here. Some devices and designs developed at the Notre Dame Center for Micro-fluidics and Medical Diagnostics will be presented as solutions to these micro-fluidic challenges.
Passive Micro Mixers for Applications in the Micro Reactor and µTAS Field
Authors: Hardt Steffen , Drese Klaus , Hessel Volker , Scho¨nfeld Friedhelm
Published: December 2008

An overview is given of current developments in micro mixing technology, where the emphasis is on liquid mixing in passive micro mixers. The mixers presented are differentiated by the hydrodynamic principle employed, and four important principles are discussed in some detail: hydrodynamic focusing, flow separation, chaotic advection and split-and-recombine flows. It is shown that these principles offer an excellent mixing performance in various dynamical regimes. Hydrodynamic focusing is a concept working very much independently of the Reynolds number of the flow. Flow separation offers a rich dynamical behavior over a Reynolds number scale of several hundred, with superior performance compared to purely diffusive mixing already found at low Reynolds numbers. For chaotic advection different implementations tailor-made for low and comparatively high Reynolds numbers exist, both leading to an exponential increase of the interface between two fluids. Split-and-recombine flows can only be realized in a close-to-ideal form in the low Reynolds number regime. Corresponding mixers can be equipped with comparatively wide channels, enabling a favorable ratio of throughput to pressure drop. The overview given in this article should enable a potential user of micro mixing technology to select the most favorable concept for the application envisaged, especially in the field of chemical process technology.
Evaluation of Single Phase Flow in Microchannels for High Flux Chip Cooling: Thermohydraulic Performance Enhancement and Fabrication Technology
Authors: Kandlikar Satish G. , Grande William J.
Published: December 2008

The increased circuit density on today’s computer chips is reaching the heat dissipation limits for air-cooled technology. Direct liquid cooling of chips is being considered as a viable alternative. This paper reviews liquid cooling in terms of technological options and challenges. The possibilities presented herein indicate a four-to ten-fold increase in heat flux over the air-cooled systems. The roadmap for single-phase cooling technology is presented to identify research opportunities in meeting the cooling demands of future IC chips. The use of three-dimensional microchannels that incorporate either microstructures in the channel of grooves in the channel surfaces may lead to enhancement in single-phase cooling. A simplified fabrication process is described that can build both classes of three-dimensional microchannels. Proof-of-concept microchannels are presented to demonstrate the efficacy of the fabrication process.
Microchannel Cooling in Computing Platforms: Performance Needs and Challenges in Implementation
Authors: Pokharna Himanshu , Masahiro Kuroda , DiStefano Eric , Mongia Rajiv , Barry Jim , Crowley Chris , Chen Weibo , Izenson Mike
Published: December 2008

Remote cooling is the established cooling scheme in notebook computers, and increasingly, other computing sectors like desktops and servers are evaluating this approach as an option for cooling future platforms. While remote cooling facilitates a larger heat exchanger than the space directly over the processor would allow, it introduces an additional thermal resistance, in particular, θp-f (plate to fluid resistance) — the resistance in getting the heat from the cold plate to the fluid. For any remote cooling system, this resistance needs to be carefully evaluated and minimized. Pumped fluid loops incorporating microchannel heat exchangers are a viable option to achieve low plate-to-fluid resistances. In this paper we will identify a reasonable target for θp-f and subsequently describe two similar but fundamentally different thermal systems to accomplish this target performance: single-phase and two-phase pumped loops. Although two phase flows are traditionally thought of as the way to accomplish the highest heat transfer coefficients and thus the lowest resistances, with microchannel heat sinks the contrast is not so acute. We will present results from our experimental work on single- and two-phase heat transfer from microchannel heat sinks and demonstrate a transition where single-phase performance matches that of two-phase operation. This will be followed by the analysis methods used to predict the heat transfer and the pressure drop data. Moreover, we will discuss system level issues and other hurdles that need to be overcome in commercialization of microchannel technology for cooling computer systems.
Direct Comparison Between a Variety of Microchannels: Part 1 — Channel Manufacture and Measurement
Authors: Eason Cormac , Dalton Tara , O’Mathu´na Cian , Davies Mark , Slattery Orla
Published: December 2008

This paper is the first part of a two part study into the pressure-flow characteristics of a range of microchannels measured over a range of typical Reynolds numbers. Here the manufacture of the channels and their resulting quality is addressed. The target application is silicon cooling. Wet Etching, Deep Reactive Ion Etching (DRIE) and Precision Sawing have been used to create microchannels in silicon and thermoset plastic. Anodic bonding has been used to bond covers onto the DRIE and Wet Etched channels. Wet etching a (100) silicon wafer using a KOH solution produced trapezoidal channels of width 577 μm and height 413μm. DRIE using the Bosch process produced rectangular channels in (100) silicon of width 304μm and height 332μm. Mechanical sawing using a Disco Dicing Saw produced near rectangular channels in both silicon and plastic. The silicon channels were 52μm wide and 423μm deep, and the plastic channels were 203μm wide by 344 or 382μm deep. Channel dimensions were measured using a scanning electron microscope. Silicon was the main material chosen, since it is possible to cut cooling channels directly into one side of a silicon device, while the electronic parts are deposited on the other, giving effective cooling with minimal thermal resistance. The plastics chosen are commonly used to encapsulate electronic packages and will also be in close proximity to the heat producing regions of the device it protects. Embossed channels on a plastic encapsulant also potentially offer a low cost mass producible means of cooling electronic devices with a low overall thermal resistance. A glass cover was anodically bonded over the silicon channels to prevent channel to channel leakage and provide optical access. The plastic channels were also covered by a glass slide, bonded in position using SU8 Photoresist spun on the glass. This paper demonstrates the feasibility of producing relatively large microchannels in two materials by three methods. Part two of this paper will describe the modular flow test system and analyze the flow friction through the channels.
An Experimental Study of Heat-Transport Characteristics of Oscillatory Flow in a Minichannel
Authors: Suzuki Osamu
Published: December 2008

The axial-heat-transport characteristics of oscillatory flow of water in mini-tubes were investigated to provide possible next-generation electronics cooling in thermal management devices. The mini-tubes were made of SUS304 with inner diameters of 0.3, 0.5, and 0.8 mm, which were smaller than those of reported in the literature. The oscillation frequency of the liquid column ranged from 0.38 to 12.5 Hz and its tidal displacement ranged from 25 to 100 mm. The effective thermal diffusivity was defined to evaluate heat transport rate for each experimental conditions and to compare with existing analytical-model results. The measured effective thermal diffusivities divided by the square of tidal displacement and angular frequency drew “tuning-curves” in the graph, which are similar to the curve drawn by the analytical-model. Regarding the magnitudes of the diffusivities, although the agreement between the measured diffusivities and calculated diffusivities are fairly good, the measured values are roughly twice higher than the prediction results at the frequencies of about 3 Hz and the lower.
Properties of a Dense Hard-Sphere Gas Near the Walls of a Microchannel
Authors: Nedea S. V. , Frijns A. J. H. , van Steenhoven A. A. , Jansen A. P. J.
Published: December 2008

A mathematical model has been developed to characterize the effect of packing of molecules of a hard-sphere dense gas near the hard walls of a microchannel. Analytical techniques, Monte Carlo (MC) methods and Molecular Dynamics (MD) simulation methods have been used to characterize the influence of the characteristic parameters such as number density, reduced density, length of the system and molecular diameter on the equilibrium properties of the gas near the hard walls of the microchannel. The height and the position of the density oscillation peaks near the wall are characterized. Comparisons between MD and MC results for particles having different diameter are presented. For the same size of the particles and moderately dense gas, MC and MD results are similar, differences in the density profiles being limited only to the oscillatory region. For different particle sizes, MD and MC results are limited to a short distance near the wall for long size systems and moderately dense fluids. The effect of the boundary (particle size) on the simulation results is increasing with η (reduced density) and it is very small in case of a dilute gas. For small η and small particle size (R) relative to length of the system L, the height of the oscillations peaks is slowly increasing with R/L, and for high densities is always decreasing with R/L. The position of these peaks depends only on the size of the particles and when R is much smaller than L, it shows a small dependence on L.
A Computational Study of Convection Heat Transfer to CO2 at Supercritical Pressures in a Vertical Mini Tube
Authors: He S. , Jiang P. X. , Xu Yi-Jun , Shi Run-Fu , Kim W. S. , Jackson J. D.
Published: December 2008

Computational simulations of experiments on turbulent convection heat transfer of carbon dioxide at supercritical pressures in a vertical tube of diameter 0.948 mm have been carried out using low-Reynolds number eddy viscosity turbulence models. The simulations were able to reproduce the general features exhibited in the experiments. The modelling study has provided valuable information on the detailed flow and turbulence fields. It has been shown that for mini tubes such as the one used in the current study, the buoyancy effect is generally insignificant. Heat transfer can be significantly impaired when the heating is strong. This is due to the reduced turbulence production, induced by the flow acceleration which is in turn caused by strong heating.
Numerical Study of Skin Friction Coefficient and Reattachment Length for a Slip Flow Encountered in a Partially Blocked Channel
Authors: Abu-Nada Eiyad , Al-Sarkhi AbdelSalam
Published: December 2008

The current research investigates the effect of Reynolds number and Knudsen number on the coefficient of skin friction and reattachment length for a micro-scale fluid flow over a step mounted on a lower wall of a micro-channel. Five Reynolds numbers are studied Re = 1, 10, 25, 50, and 75 and the Knudsen number is varied from 1×10−3 to 0.1. Finite difference method with non-uniform grid is used to solve the incompressible Navier Stokes equations accompanied with velocity slip boundary condition. As Knudsen number (Kn) decreases the magnitude of modified local shear stress (1/2 Cf Re), on the upper wall of the channel, increases. In the circulation zone behind the step and for the case of high Reynolds number (Re = 50 and Re = 75) the modified local shear stress increases as Knudsen number increases. Results show that the modified total skin friction (1/2 CD Re) decreases as the Knudsen number increases. The modified total skin friction drops significantly with Knudsen number for Kn >= 1 × 10−2. However, (1/2 CD Re) is relatively independent of Knudsen number for Kn < 1 × 10−2. Finally, for 1 × 10−2 < Kn < 0.1, as Knudsen number increase the reattachment length increases.
Experimental and Numerical Investigation of Convection Heat Transfer of CO2 at Supercritical Pressures in a Vertical Mini Tube
Authors: Jiang Pei-Xue , Xu Yi-Jun , Shi Run-Fu , He S.
Published: December 2008

Convection heat transfer of CO2 at supercritical pressures in a vertical mini tube with a diameter of 0.948 mm was investigated experimentally and numerically. The local heat transfer coefficients, bulk fluid temperatures and wall temperatures were measured and presented. The effects of inlet fluid temperature, fluid pressure, mass flow rate, heat flux and wall thickness on the convection heat transfer in the mini tube were investigated. The experimental results were compared with calculated results using well-known correlations and numerical simulations. The results showed that the variable thermophysical properties of supercritical CO2 significantly influenced the convection heat transfer in the vertical mini tube and that for the studied conditions the influence of the wall thickness on the convection heat transfer in the mini tube was not great. For bulk fluid temperatures higher than the pseudo-critical temperature, the simulation results and the correlation results for the convection heat transfer coefficients in the mini tube corresponded well to the experimentally measured results.
An Experimental Investigation of Gaseous Flow Characteristics in Microchannels
Authors: Tang G. H. , He Y. L.
Published: December 2008

Gaseous flow characteristics in fused silica microtubes and square microchannels are studied experimentally. The existing works in the literature on experimental gaseous flow are analyzed. The data in fused silica micro circular tubes with diameters ranging from 50 μm to 201 μm and the data in fused silica micro square channels with hydraulic diameter ranging from 52 μm to 100 μm show that the flow friction factors are in good agreement with the theoretical prediction for conventional tubes and no distinguishable deviation is observed. The transition Reynolds number is around 2000 and a slight early transition from laminar to turbulent is observed due to the compressibility effect. For the helium flow in fused silica microtubes with inner diameters ranging from 10 μm to 20 μm, the decrease in friction factor is observed. In addition, factors including roughness, compressibility and rarefaction that may have significant effects on flow characteristics in microchannels are discussed.
Capillarity Driven Interface Motion in a Flat Triangular Minichannel
Authors: Amyot O. , Geoffroy S. , Plouraboue´ F. , Prat M.
Published: December 2008

In microchannel flow, gas-liquid interface behavior is important for many applications, e.g. micro-reactors, micro heat pipes to name only two of them. Microfluidic channels shape are generally rectangular or triangular with associated solid corner. Those corners are interesting for they drastically increase capillary effects of wetting liquids compared to smooth solid boundaries. We study capillarity driven gas–liquid flows in a flat triangular channel. A channel of triangular cross section was micro-machined in a polymeric material and covered by a transparent plexiglas plate. The wetting fluid is injected at a controlled flow rate and the interface motion along the corners is recorded with a CCD video camera. A simple lubrication theory predicts the temporal evolution of the liquid-gas interface. A good agreement is found between those predictions and experimental results. the theory also predicts when the invasion of the channel bulk occurs. The dynamics of the bulk meniscus is discussed. The results suggest that the bulk meniscus dynamics is affected by the growth of the liquid fingers that develop along the edges of the channel.
Head Loss and Flow Characteristics for Turning Flow Driven by Surface Tension Force Inside Open Microchannel
Authors: Chen Y. F. , Chen M. H. , Yu R. J. , Tseng F. G. , Chieng Ching-Chang
Published: December 2008

Present study demonstrates the head loss and the flow characteristics as the open microchannel makes turns. The microchannels are of various aspect ratios of depth/width ranging from 0.5 to 2, and makes turns with different angles ranging from 60 to 120 degrees. The investigations are performed both by experiments and numerical simulations based on first principle equations. For the open channel system, the flow is mainly driven by surface tension under same pressure atmosphere. For liquid flow in open microchannel without turn, the liquid front velocity decreases but the interface area of liquid-gas increase as flow moves downstream. For turning flows, liquid front velocity is decreased firstly and then increased sharply at the turning point. Furthermore, the liquid front velocity can be increased for higher aspect ratio of channel height and width, and the effect of aspect ratio is significant up to aspect ratio between 1.0–1.5. Detailed flow characteristics as well as the head loss coefficient due to microchannel turning are discussed.