High Power Laser Welding

A review of recent developments in high power, carbon dixoide laser welding is presented. Deep penetration welding in stainless steel to 0.5-in. thick, high speed welding in thin gage rimmed steel and gas shielded welding in Ti-6Al-4V alloy are described. The effects of laser power, power density, focusing optics, gas-shielding techniques, material properties and weld speed on weld quality and penetration are discussed. It is shown that laser welding performance in thin materials is comparable to that of electron beams. It is further shown that high quality welds, as evidenced by NDT, mechanical and metal-lographic tests, can be achieved. The potential of the laser for industrial welding applications is indicated

Electron beam, laser beam and plasma arc welding studies

This program was undertaken as an initial step in establishing an evaluation framework which would permit a priori selection of advanced welding processes for specific applications. To this end, a direct comparison of laser beam, electron beam and arc welding of Ti-6Al-4V alloy was undertaken. Ti-6Al-4V was selected for use in view of its established welding characteristics and its importance in aerospace applications

Toll-like receptor 4 in experimental kidney transplantation: early mediator of endogenous danger signals

The role of toll-like receptors (TLRs) has been described in the pathogenesis of renal ischemia/reperfusion injury, but data on the expression and function of TLR4 during renal allograft damage are still scarce. We analyzed the expression of TLR4 in an experimental rat model 6 and 28 days after allogeneic kidney transplantation in comparison to control rats and rats after syngeneic transplantation. On day 6, a significant induction in TLR4 expression - restricted to the glomerular compartment - was found in acute rejecting allografts only. TLR4 expression strongly correlated with renal function, and TLR4 induction was accompanied by a significant increase in CC chemokine expression within the graft as well as in urinary CC chemokine excretion. TLR4 induction may be caused by an influx of macrophages as well as TLR4-expressing intrinsic renal cells. Fibrinogen deposition in renal allografts correlated with renal TLR4 expression and may act as a potent stimulator of chemokine release via TLR4 activation. This study provides, for the first time, data about the precise intrarenal localization and TLR4 induction after experimental kidney transplantation. It supports the hypothesis that local TLR4 activation by endogenous ligands may be one pathological link from unspecific primary allograft damage to subsequent chemokine release, infiltration and activation of immune cells leading to deterioration of renal function and induction of renal fibrosis. Copyright (c) 2012 S. Karger AG, Base

Adolescent Healthcare Brokering: Prevalence, Experience, Impact, and Opportunities

BACKGROUND: Limited health literacy disproportionately affects those with limited English proficiency (LEP). Parents with LEP might rely on their adolescent children to interpret health information. We call this adolescent health care brokering. This study uncovers the prevalence of brokering, kinds of tasks, emotional and academic impact, and desired support. METHODS: We invited 165 students from health classes (in a community in which 29.8% are foreign-born and 53.4% speak another language at home) to complete a survey. We used IBM SPSS to calculate descriptive statistics. RESULTS: Of the 159 who received parental consent and assented, 54.1% (n=86) assist with healthcare tasks. When brokering, 80.2% (n=69) translate. Most common tasks were talking to a doctor, reading prescriptions, and searching on the Internet. Participants were most confident reading prescriptions and talking to a doctor and least confident finding healthcare services. Among brokers, 29.1% (n=24) missed school; 33.7% did not complete homework. They most wanted to learn about filling out insurance forms and talking to doctors. CONCLUSIONS: Despite assurances that children are not permitted to interpret, adolescents are acting as healthcare brokers. The impact can be academic and emotional. Findings indicate a need for further research and support for adolescents who want to learn about healthcare tasks

The Adolescent Health Care Broker – Adolescents Interpreting for Family Members and Themselves in Health Care

Parents with limited English proficiency might rely on their adolescent children to interpret health information. We call this adolescent healthcare brokering. Using a mixed-methods, transformative research approach rooted in grounded theory, we sought to answer these questions: (a) “What is happening? What are people doing?” and (b) “What do these stories indicate? What might they suggest about social justice?” High school students from a community in which 53.4% speak another language at home were invited to participate in a survey and focus groups. Of 238 survey participants, 57.5% (n=137) indicated they assisted with healthcare tasks. When doing so, 81.7% (n=112) translated. Common tasks were reading prescriptions and talking to doctors. While some participants cited negative emotions associated with brokering, the net emotion was positive. Focus groups (n=11) revealed that tasks varied broadly in complexity and type, emotional experiences were dichotomous, and access to interpreting services and other supports was inconsistent

Projected impacts of 21st century climate change on diapause in Calanus finmarchicus

Diapause plays a key role in the life cycle of high latitude zooplankton. During diapause animals avoid starving in winter by living in deep waters where metabolism is lower and met by lipid reserves. Global warming is therefore expected to shorten the maximum potential diapause duration by increasing metabolic rates and by reducing body size and lipid reserves. This will alter the phenology of zooplankton, impact higher trophic levels and disrupt biological carbon pumps. Here we project the impacts of climate change on the key North Atlantic copepod Calanus finmarchicus under IPCC RCP 8.5. Potential diapause duration is modelled in relation to body size and overwintering temperature. The projections show pronounced geographic variations. Potential diapause duration reduces by more than 30% in the Western Atlantic, whereas in the key overwintering centre of the Norwegian Sea it changes only marginally. Surface temperature rises, which reduce body size and lipid reserves, will have a similar impact to deep water changes on diapause in many regions. Because deep water warming lags that at the surface, animals in the Labrador Sea could offset warming impacts by diapausing in deeper waters. However, the ability to control diapause depth may be limited

Spontaneous renal tumors in two rats from a thirteen week rodent feeding study with grain from molecular stacked trait lepidopteran and coleopteran resistant (DP-ØØ4114-3) maize

AbstractA thirteen week feeding study was conducted by feeding young adult male and female Sprague Dawley [Crl:CD®(SD)] rats diets containing grain from genetically modified (GM) DP-ØØ4114-3 maize that was either untreated (4114) or treated in the field with glufosinate ammonium (4114GLU). Control rats were fed diets containing the same concentration of near isogenic, non-GM maize grain (091) or one of three types of commercially available non-GM maize grain. At the end of the in-life phase, renal tubule tumors were reported in two male rats consuming diets containing 4114 maize grain. An expert panel of pathologists was convened as a Pathology Working Group (PWG) to review coded kidney histology sections from control (091) and treated (4114 and 4114GLU) male rats. The objectives were for the panel to characterize the histopathologic findings and to interpret their relationship to consumption of the indicated diet. The PWG concluded unanimously that the kidney tumors were characteristic of amphophilic-vacuolar (AV) tumors and AV atypical tubular hyperplasia which represent a distinctive phenotype that has been reported to occur sporadically in young Sprague Dawley Rats. The PWG determined that the neoplasms and atypical tubular hyperplasias were multicentric and bilateral which typifies tumors of familial origin. Degenerative/regenerative or cytotoxic changes consistent with nephrotoxicity leading to tumor induction were not observed in these rats and thus supports the conclusion that tumors were unrelated to consumption of the test diet. It was the unanimous opinion of the PWG that the proliferative renal tubule cell lesions were spontaneous and not related to consumption of diets containing 4114 maize grain

Nouvelles trappes à sédiment destinées aux milieux peu profonds vidangeables

Les mesures de taux de sédimentation en milieux aquatiques peu profonds sont rares et sont souvent réalisées à l'aide de méthodes inadaptées. Les trappes à sédiment utilisées ont au minimum 25 cm de haut. Par conséquent, pour beaucoup de milieux peu profonds, plus de 25 % de la colonne d'eau ne sont pas échantillonnés. Nous avons pallié ce problème en développant un réceptacle mis en place dans les sédiments et destiné à recevoir des trappes à sédiment cylindriques. Le sommet des trappes peut alors être situé à moins de 5 cm de la surface des sédiments. Ce système est utilisable pour des milieux de profondeur inférieure à cinq mètres. Nos résultats montrent que les trappes à sédiments généralement utilisées sous-estiment de 35 à 79 % du taux de sédimentation. Les particules négligées proviennent des flux sédimentaires primaire et secondaire.Sediment traps are a unique tool that can be used to investigate particle settling flux throughout the water column, whereas other methods such as sediment dating can only measure accumulation rates of bottom sediments. Several works on trapping efficiency have shown that cylindrical traps with height/diameter ratio greater than to 5 (10 in turbulent systems) are the more appropriate instruments to correctly measure the downward settling flux of particulate matter. Furthermore, traps with a diameter narrower than 5 cm should be avoided. It is well documented that bottle-type vessels overestimate the settling sediment whereas funnels and flat containers underestimate it. All this support the idea that an ideal trap must be at least 25 cm high, and in this sense, numerous studies investigating shallow aquatic systems have neglected a large proportion of the water column. Consequently, mechanical and biological processes occurring in this layer of the water column have not been taken into accountWe have overcome this problem with a structure composed of two parts (figure 2).The first part is a receptacle (bucket) buried in the sediment and intended to receive cylindrical traps. The top of the receptacle is placed 2 cm above the sediment. A guide made of a rope covered with a PVC tube is placed in the centre of the receptacle. This receptacle is intended to receive cylindrical traps whose tops stand less than 5 cm higher than the surface of the sediments.The second part is composed of seven cylinders (height/diameter ratio=10) which are fixed in a PVC disc 600 mm in diameter and 15 mm deep. The cylinders are placed around the central axis of the PVC disc. The bottom of the cylinders is closed with a removable polyethylene cap. Another cylinder, through which the guide can slide, is placed on the central axis. The bottom part of this last cylinder is ballasted with concrete. The stability of this second part, during both deposition and removal steps, is ensured by the low density of the PVC disc, the ballast at the bottom of the central cylinder, and the symmetry of the structure. This removable part may be lifted from the receptacle with three 2 mm diameter ropes attached to the PVC disc and fixed to a float. This apparatus may be used as deep as five meters.The sediment traps were tested in two extensively-managed fish ponds in North-Eastern France. Our investigations showed that tubes with a diameter between 26 and 140 mm could be efficiently used to estimate the sedimentation rate, whereas cylinders with a narrower diameter missed a large amount of particles. The use of tubes with a diameter above 50 mm, which is preferable for the study of turbulent systems, seems to allow the collection of sufficient sediment during a short period of time. We selected tubes with a diameter of 57 mm, which made it possible to handle them easily during the removal. Our investigations showed that in turbulent systems and for high sedimentation rates (> 5 kg·m-2 ·month-1), the top of the cylinders must be placed 1 cm above the top of the PVC disc. When considering low sedimentation rates (< 5 kg·m-2 ·month-1), we did not observe any significant differences between the cylinders placed 0 and 1 cm above the PVC disc.Complementary investigations were conducted in order to compare sedimentation rates estimated 1) by the apparatus we designed, in which the top of the cylinders was placed 5 cm above the sediment surface, 2) by traditional traps (57 mm in diameter and a height/diameter ratio of 5) in which the top of the cylinders was 28.5 cm above the sediment surface.These results showed that in shallow systems (1.2 m deep), traditional traps underestimate the downward settling flux of particulate matter by 35 to 79%. Furthermore, we compared the organic matter content of the sediment collected by the two types of traps with the organic matter content of bottom sediment, suspended particles, and submerged macrophytes. Results showed that the underestimation of particles was not only due to the resuspension of bottom sediment, but also to the sedimentation of phytoplankton and submerged macrophyte fragments which are not collected by the traditional traps

Exogenously added GPI-anchored tissue inhibitor of matrix metal loproteinase-1 (TIMP-1) displays enhanced and novel biological activities

The family of tissue inhibitors of metalloproteinases (TIMPs) exhibits diverse physiological/biological functions including the inhibition of active matrix metalloproteinases, regulation of proMMP activation, cell growth, and the modulation of angiogenesis. TIMP-1 is a secreted protein that can be detected on the cell surface through its interaction with surface proteins. The diverse biological functions of TIMP-1 are thought to lie, in part, in the kinetics of TIMP-1/MMP/surface protein interactions. Proteins anchored by glycoinositol phospholipids (GPIs), when purified and added to cells in vitro, are incorporated into their surface membranes. A GPI anchor was fused to TIMP-1 to generate a reagent that could be added directly to cell membranes and thus focus defined concentrations of TIMP-1 protein on any cell surface independent of protein-protein interaction. Unlike native TIMP-1, exogenously added GPI-anchored TIMP-1 protein effectively blocked release of MMP-2 and MMP-9 from osteosarcoma cells. TIMP-1-GP1 was a more effective modulator of migration and proliferation than TIMP-1. While control hTIMP-1 protein did not significantly affect migration of primary microvascular endothelial cells at the concentrations tested, the GPI-anchored TIMP-1 protein showed a pronounced suppression of endothelial cell migration in response to bFGF. In addition, TIMP-1-GPI was more effective at inducing microvascular endothelial proliferation. In contrast, fibroblast proliferation was suppressed by the agent. Reagents based on this method should assist in the dissection of the protease cascades and activities involved in TIMP biology. Membrane-fixed TIMP-1 may represent a more effective version of the protein for use in therapeutic expression