Fibrinogen adsorption and platelet adhesion to silica surfaces with stochastic nanotopography

In this study, the effect of surface nanoscale roughness on fibrinogen adsorption and platelet adhesion was investigated. Nanorough silica surfaces with a low level of surface roughness (10 nm Rrms) were found to support the same level of fibrinogen adsorption as the planar silica surfaces, while nanorough silica surfaces with higher levels of surface roughness (15 nm Rrms) were found to support significantly less fibrinogen adsorption. All surfaces analyzed were found to support the same level of platelet adhesion; however, platelets were rounded in morphology on the nanorough silica surfaces while platelets were spread with a well-developed actin cytoskeleton on the planar silica. Unique quartz crystal microbalance with dissipation monitoring (QCM-D) responses was observed for the interactions between platelets and each of the surfaces. The QCM-D data indicated that platelets were more weakly attached to the nanorough silica surfaces compared with the planar silica. These data support the role of surface nanotopography in directing platelet-surface interactions even when the adsorbed fibrinogen layer is able to support the same level of platelet adhesion

Pothole Reporting System

The purpose of this project is to create a pothole detection device that can be attached to the underside of a commercial vehicle. Potholes cost motorists around 6.4 billion dollars annually, thus demonstrating the need for a system to aid with the detections and reporting of potholes. The four systems we needed to consider for the implementation of this project were the power system, the sensing system, the data processing system, and the reporting and logging system. Power pulled from the vehicle will enable the sensors and data processing module. The data processing module will analyze the readings from the sensors and output pothole data to the logging and reporting system. The logging and reporting system, located on an android mobile device, will store the pothole locations on a cloud server

Mapping the Learning Pathways of Larval Zebrafish through Positively Stimulating Their Reward Pathways Using Paramecium

Zebrafish rely on visual acuity to hunt for prey all of their lives, for this reason, their eyesight develops when they are embryos. The zebrafish in this experiment are between 5 and 20 days old. Once their egg yolks are completely reabsorbed the zebrafish have a need to eat, and only then will they have an interest in eating Paramecium. The zebrafishes’ eyes will be able to see clearly by 5 days post fertilization as well, so when food is introduced to them, a certain colored light will be simultaneously shined in the same direction as the one the food is coming from. The purpose of this experiment is to use different colored visual cues to train larval zebrafish into expecting food whenever they are shone. The usage of lights also tests their extraordinary visual abilities. Red lights will be associated with a food reward in one group of larvae, and in the second group, green lights will be associated with a food reward, demonstrating associative learning. The zebrafishes’ unconditioned response (eating Paramecium when they appear) will be trained into a conditioned response (looking to eat Paramecium when the light is shined). After they have been conditioned to respond to these signals, the zebrafishes’ brains will be studied to find changes in their neural pathways. The expected results of this experiment should lead to the fish thinking Paramecium are coming at just the glimpse of a light

Fast, scalable, Bayesian spike identification for multi-electrode arrays

We present an algorithm to identify individual neural spikes observed on high-density multi-electrode arrays (MEAs). Our method can distinguish large numbers of distinct neural units, even when spikes overlap, and accounts for intrinsic variability of spikes from each unit. As MEAs grow larger, it is important to find spike-identification methods that are scalable, that is, the computational cost of spike fitting should scale well with the number of units observed. Our algorithm accomplishes this goal, and is fast, because it exploits the spatial locality of each unit and the basic biophysics of extracellular signal propagation. Human intervention is minimized and streamlined via a graphical interface. We illustrate our method on data from a mammalian retina preparation and document its performance on simulated data consisting of spikes added to experimentally measured background noise. The algorithm is highly accurate

Application of nanomaterials in two-terminal resistive-switching memory devices

Nanometer materials have been attracting strong attention due to their interesting structure and properties. Many important practical applications have been demonstrated for nanometer materials based on their unique properties. This article provides a review on the fabrication, electrical characterization, and memory application of two-terminal resistive-switching devices using nanomaterials as the active components, including metal and semiconductor nanoparticles (NPs), nanotubes, nanowires, and graphenes. There are mainly two types of device architectures for the two-terminal devices with NPs. One has a triple-layer structure with a metal film sandwiched between two organic semiconductor layers, and the other has a single polymer film blended with NPs. These devices can be electrically switched between two states with significant different resistances, i.e. the ‘ON’ and ‘OFF’ states. These render the devices important application as two-terminal non-volatile memory devices. The electrical behavior of these devices can be affected by the materials in the active layer and the electrodes. Though the mechanism for the electrical switches has been in argument, it is generally believed that the resistive switches are related to charge storage on the NPs. Resistive switches were also observed on crossbars formed by nanotubes, nanowires, and graphene ribbons. The resistive switches are due to nanoelectromechanical behavior of the materials. The Coulombic interaction of transient charges on the nanomaterials affects the configurable gap of the crossbars, which results into significant change in current through the crossbars. These nanoelectromechanical devices can be used as fast-response and high-density memory devices as well

Renal angiomyolipoma presenting with massive retroperitoneal haemorrhage due to deranged clotting factors: a case report

BACKGROUND: Angiomyolipomata of the kidney are unusual lesions composed of abnormal vasculature, smooth muscle, and adipose elements. They may be associated with tuberous sclerosis and occasionally present with flank pain, a palpable mass, and gross haematuria. As angiomyolipomata grow their risk of bleeding increases, with a greater than 50% chance of significant bleeding in lesions > 4 cm; anticoagulant therapy accentuates this risk. CASE PRESENTATION: A case of massive retroperitoneal haemorrhage in a patient on warfarin is presented. The underlying diagnosis of renal angiomyolipoma was diagnosed based on CT findings. Emergency resuscitation and selective interpolar arterial embolization was performed which saved the patient's life as well as his kidney. CONCLUSION: This case illustrates the clinical scenario of massive retroperitoneal haemorrhage in an anticoagulated patient with renal angiomyolipomata. In the emergent situation, adequate resuscitation along ABC principles, as well as control of haemorrhage with either nephrectomy (partial or radical), non-selective renal arterial embolization, or selective embolization of the feeding vessel(s), is necessary. For this to occur, it is imperative to consider the diagnosis early in warfarinized patients (and others at risk of bleeding) who present with abdominal pain. The authors hope this case report highlights to readers the clinical scenario of massive retroperitoneal haemorrhage in anticoagulated patients with renal angiomyolipomata so that they can deal appropriately with such presentations

Intrauterine environmental and genetic influences on the association between birthweight and cardiovascular risk factors: studies in twins as a means of testing the fetal origins hypothesis

Evidence has accumulated that low birthweight is associated with several risk factors for cardiovascular disease. However, it is not known whether or not these associations are due to a programmed response to intrauterine malnutrition or genetic factors influencing both birthweight and cardiovascular risk factors. Twin studies offer a unique opportunity to distinguish between intrauterine and genetic origins of the association between birthweight and cardiovascular risk. In our twin cohort, low birthweight was associated with insulin resistance, lower HDL and shorter height within both dizygotic and monozygotic twin pairs, suggesting that these associations are, at least in part, independent of genetic factors. In contrast, low birthweight was associated with blood pressure, total and LDL cholesterol, fibrinogen and sympathetic activation within dizygotic twin pairs, but not within monozygotic twin pairs. These differences between dizygotic and monozygotic twins suggest that these associations are, at least in part, due to genetic factors. Therefore, both intrauterine environmental and genetic factors appear to play a role in the association between birthweight and cardiovascular risk factors. In the future, strategies may be developed targeted at improving or preventing impaired intrauterine growth. However, the effects of interventions that comprise changes in environment within the normal range may be limited due to the possible important role of genetic factor

Thymocytes in Lyve1-CRE/S1pr1(f/f) Mice accumulate in the Thymus due to cell-intrinsic loss of sphingosine-1-Phosphate receptor expression

T cell emigration from the thymus is essential for immunological homeostasis. While stromal cell-produced sphingosine-1-phosphate (S1P) has been shown to promote thymocyte egress via the S1P receptor, S1PR1, the significance of S1P/S1PR1 signaling in the thymic stromal cells that surround T cells remains unclear. To address this issue, we developed conditional knockout mice (Lyve1-CRE/S1pr1f/f mice) in which S1pr1 was selectively targeted in cells expressing the lymphatic endothelial cell marker, Lyve1. In these mice, T cells were significantly reduced in secondary lymphoid tissues, and CD62L(+) mature CD4 and CD8 single-positive (SP) T cells accumulated in the medulla failed to undergo thymus egress. Using a Lyve1 reporter strain in which Lyve1 lineage cells expressed tdTomato fluorescent protein, we unexpectedly found that a considerable proportion of the thymocytes were fluorescently labeled, indicating that they belonged to the Lyve1 lineage. The CD4 and CD8 SP thymocytes in Lyve1-CRE/S1pr1f/f mice exhibited an egress-competent phenotype (HSA(low), CD62L(high), and Qa-2(high)), but were CD69(high) and lacked S1PR1 expression. In addition, CD4 SP thymocytes from these mice were unable to migrate to the periphery after their intrathymic injection into wild-type (WT) mice. In contrast, WT T cells could migrate to the periphery in both WT and Lyve1-CRE/S1pr1f/f thymuses. These results demonstrated that thymocyte egress is mediated by T cell-expressed, but not stromal cell-expressed, S1PR1 and caution against using the Lyve1-CRE system for selectively gene deletion in lymphatic endothelial cells

Seed conformal blocks in 4D CFT

We compute in closed analytical form the minimal set of \u201cseed\u201d conformal blocks associated to the exchange of generic mixed symmetry spinor/tensor operators in an arbitrary representation (\u2113, \u2113) of the Lorentz group in four dimensional conformal field theories. These blocks arise from 4-point functions involving two scalars, one (0, |\u2113 12 \u2113|) and one (|\u2113 12 \u2113|, 0) spinors or tensors. We directly solve the set of Casimir equations, that can elegantly be written in a compact form for any (\u2113, \u2113), by using an educated ansatz and reducing the problem to an algebraic linear system. Various details on the form of the ansatz have been deduced by using the so called shadow formalism. The complexity of the conformal blocks depends on the value of p = |\u2113 12 \u2113| and grows with p, in analogy to what happens to scalar conformal blocks in d even space-time dimensions as d increases. These results open the way to bootstrap 4-point functions involving arbitrary spinor/tensor operators in four dimensional conformal field theories

The Evolution of Bat Vestibular Systems in the Face of Potential Antagonistic Selection Pressures for Flight and Echolocation

PMCID: PMC3634842This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited