Direct numerical simulations of the flow around wings with spanwise waviness at a very low Reynolds number

Inspired by the pectoral flippers of the humpback whale, the use of spanwise waviness in the leading edge has been considered in the literature as a possible way of improving the aerodynamic performance of wings. In this paper, we present an investigation based on direct numerical simulations of the flow around infinite wavy wings with a NACA0012 profile, at a Reynolds number Re=1000Re=1000. The simulations were carried out using the Spectral/hp Element Method, with a coordinate system transformation employed to treat the waviness of the wing. Several combinations of wavelength and amplitude were considered, showing that for this value of Re the waviness leads to a reduction in the lift-to-drag ratio (L/D), associated with a suppression of the fluctuating lift coefficient. These changes are associated with a regime where the flow remains attached behind the peaks of the leading edge while there are distinct regions of flow separation behind the troughs, and a physical mechanism explaining this behaviour is proposed

Recombinant gamma interferon induces hypertriglyceridemia and inhibits post-heparin lipase activity in cancer patients.

Animals suffering from malignancy or chronic infection develop characteristic metabolic abnormalities, including a well-defined hypertriglyceridemic state. These abnormalities have been attributed to release of one or more mediators from activated macrophages. We report that cancer patients receiving RIFN-gamma, a potent macrophage activator, at doses of greater than or equal to 0.25 mg/m2/d i.m. show marked increases in triglyceride but not in cholesterol levels (pretreatment triglyceride level of 180 +/- 190 mg/dl [mean +/- SD] vs. a day-14 level of 370 +/- 242 mg/dl, n = 23, p less than 0.001 by the paired t test). This hypertriglyceridemia was characterized by an increase in very low-density lipoproteins and a decrease in plasma post-heparin lipase activity, consistent with defective triglyceride clearance (mean pretreatment lipase level of 2.1 mumol/ml/h vs. a day-14 level of 1.2 mumol/ml/h, n = 6, p = 0.02 by the paired t test). rIFN-gamma did not directly inhibit lipoprotein lipase enzymatic activity in vitro. Other possible mechanisms of action, such as suppression of lipase by an rIFN-gamma-induced mediator released from activated macrophages, or a direct effect of interferon on lipase biosynthesis, require further investigation. Our observations provide evidence that factors produced by the immune system can regulate lipid metabolism in man

Thin-Film Metamaterials called Sculptured Thin Films

Morphology and performance are conjointed attributes of metamaterials, of which sculptured thin films (STFs) are examples. STFs are assemblies of nanowires that can be fabricated from many different materials, typically via physical vapor deposition onto rotating substrates. The curvilinear--nanowire morphology of STFs is determined by the substrate motions during fabrication. The optical properties, especially, can be tailored by varying the morphology of STFs. In many cases prototype devices have been fabricated for various optical, thermal, chemical, and biological applications.Comment: to be published in Proc. ICTP School on Metamaterials (Augsut 2009, Sibiu, Romania

The Detection of Signals in Noise: A Comparison Between the Human Detector and an Electronic Detector

Control Systems Laboratory changed its name to Coordinated Science LaboratoryContract DA-36-039-SC-5669

The growth of InGaAsP by CBE for SCH quantum well lasers operating at 1.55 and 1.4 [mu]m

InGaAsP has been grown by CBE at compositions of 1.1, 1.2 and 1.4 [mu]m for the development of MQW-SCH lasers. The observed incorporation coefficients for TMI and TEG show strong temperature sensitivity while the phosphorus and arsenic incorporation behavior is constant over the substrate temperature range explored, 530 to 580[deg]C setpoint. For higher substrate temperatures the growth rate increases with the largest growth rates occurring for the 1.4 [mu]m quaternary. Low temperature photoluminescence indicates the possibility of compositional grading or clustering for the 1.1 [mu]m material and also for the 1.2 [mu]m material grown at the lowest substrate temperature. The final laser structure was grown with the InP cladding regions grown at 580[deg]C with the inner cladding and active regions grown at 555[deg]C. Using this approach we have successfully grown MQW-SCH lasers with the composition of the active InxGa1-xAs ranging from x=0.33 to x=0.73. Threshold current densities as low as 689 A/cm2 have been measured for an 800 [mu]m x 90 [mu]m broad area device with x=0.68.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30056/1/0000424.pd

The design of an ECR plasma system and its application to InP grown by CBE

An electron cyclotron resonance (ECR) plasma system has been designed for the purpose of using an excited beam of gases during CBE growth. The system was designed to use hydrogen, nitrogen and argon. An ECR plasma system has the ability to ignite a low pressure and low temperature plasma with very low ion energies, which should minimize any damage to the growing layer. The motivation behind using a plasma during growth is the ability of atomic hydrogen to remove contaminants from the growing layer and to enhance the decomposition of organometallic precursors at low substrate temperatures. InP grown with a hydrogen plasma showed an n-type background carrier concentration of 6.0X1016 cm-3, with a rough surface and a strong photoluminescence peak at 1.378 eV. A control sample grown with excess hydrogen but without the plasma had a background carrier concentration of 1.0X1015 cm-3, a 77 K mobility of 65,000 cm2/V[middle dot]s and a very weak photoluminescence peak at 1.378 eV. The most likely cause for the layer degradation during plasma growth is an intrinsic defect such as an antisite defect or a vacancy. The n-type nature of the layer and the relatively high carrier concentration would seem to exclude the possibility of carbon or any other unintentional impurities.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29336/1/0000403.pd

The optimization of InxGa1-xAs and InP growth conditions by CBE

Minimization of the number of experiments needed to fully characterize and optimize the growth of epitaxial material is the first important step in realizing state of the art device structures. While widely used in some fields such as chemical engineering, response surface modeling (RSM) has been little used in crystal growth applications. Using RSM, input parameters such as substrate temperature hydride injector temperature and V/III ratio, were simultaneously adjusted to characterize the crystal growth process. This technique identified interactions among parameters, minimized the number of experiments necessary to understand and optimize the process, and minimized the variability of the growth process. RSM has been applied to the CBE growth of InGaAs and InP with the purpose of generating an operating point at which both good surface morphology and high mobility material can be produced. Although the best 77 K InP mobility was 70,000 cm2/V...s, in order to improve the surface quality the input parameters were changed so that the final mobility was 37,000 cm2/V...s. Although the quality of the InGaAs layers showed a dependence on the reactor history, there did not appear to be any sensitivity to variations made in the operating conditions. The best 77 K InGaAs mobility was 62,500 cm2/V...s.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29335/1/0000402.pd

Applying refinement to the use of mice and rats in rheumatoid arthritis research

Rheumatoid arthritis (RA) is a painful, chronic disorder and there is currently an unmet need for effective therapies that will benefit a wide range of patients. The research and development process for therapies and treatments currently involves in vivo studies, which have the potential to cause discomfort, pain or distress. This Working Group report focuses on identifying causes of suffering within commonly used mouse and rat ‘models’ of RA, describing practical refinements to help reduce suffering and improve welfare without compromising the scientific objectives. The report also discusses other, relevant topics including identifying and minimising sources of variation within in vivo RA studies, the potential to provide pain relief including analgesia, welfare assessment, humane endpoints, reporting standards and the potential to replace animals in RA research