387 research outputs found
Ablation of Post Transplant Atrial Flutter and Pseudo-fibrillation Using Magnetic Navigation via a Superior Approach.
Ablation of cavotricuspid ishtmus flutter and atrial tachycardia in a complex substrate has never been reported using remote navigation via superior approach. Venous access was obtained via right internal jugular for ablation and left subclavian for duodecapolar catheter placement into the coronary sinus. In a posttransplant patient presenting with both regular and irregular tachycardia, both cavotricuspid isthmus flutter in the donor and atrial tachycardia in the recipient was mapped using a two catheter approach. Successful ablation of typical atrial flutter and anastomotic block was achieved. This is the first report of successful ablation of cavotricuspid isthmus flutter and posttransplant atrial tachycardia using magnetic navigation via superior approach. Using only two catheters, this approach is logical and feasible in complex substrates with interrupted inferior venous access
Study of Biaxial Fatigue Behavior of Fiber Reinforced Polymers Under Tensile and Shear Loadings
Fiber reinforced polymers are used in many structural applications in the
aerospace and automotive industries because of their high strength to weight and high
modulus to weight ratios. In many of these applications, they are used as thin laminated
panels comprising of multiple layers of continuous fibers embedded in a polymer matrix.
In general, these laminates behave as an orthotropic material and their properties are
direction-dependent. While their uniaxial static and fatigue characteristics have been
studied extensively, their biaxial static and fatigue characteristics are not well established.
One reason for this is the difficulty of conducting biaxial tests, especially under cyclic
loading conditions. The objectives of the current research are two folds: (1) develop a
biaxial test method that can be applied to a range of normal and shear loadings, and (2)
study the biaxial fatigue behavior of a fiber reinforced polymer laminate using the new
test method.
The test method developed in this research is based on a butterfly-shaped Arcan
specimen. The versatility of the Arcan specimen is that it can be utilized for testing
materials under uniaxial normal loading, shear loading or a combination of in-plane
normal and shear loadings. The laminate considered in this study was a [0/90/04/0]S Eglass/epoxy.
Finite element analysis of a butterfly-shaped Arcan specimen was conducted first to establish its optimum geometry and delineate the importance of the
stiffness of the test fixture on the stresses in the significant section of the specimen. An
Arcan loading fixture was designed with the capability of loading of flat laminate
specimens under various combinations of in-plane tensile and shear stresses. Quasi-static
and fatigue tests were conducted with four different specimen configurations containing
either 0, 30, 45 or 90o
fiber orientations in the outer layers. The quasi-static strength
followed a quadratic failure envelope on a normal stress-shear stress plane. Biaxial
fatigue tests were conducted under combined tensile and shear stresses to determine the
effect of biaxiality on the fatigue performance of the laminate. Development of fatigue
damage under biaxial loading was also studied. A new fatigue life prediction model was
proposed that can be used to account for the effect of biaxiality on the fatigue life of fiber
reinforced polymer laminates.Ph.D.Automotive Systems Engineering, College of Engineering and Computer ScienceUniversity of Michigan-Dearbornhttp://deepblue.lib.umich.edu/bitstream/2027.42/136076/1/Mandapati Final Approved Dissertation.pdfDescription of Mandapati Final Approved Dissertation.pdf : Dissertatio
The Role and Mechanism of Action of BRK in Tamoxifen-resistant Breast Cancer
The anti-Estrogen Receptor (ER) therapy Tamoxifen has historically been used as a first -line
treatment against ER-positive breast cancer. However, 30% of Tamoxifen-treated tumours develop
resistance against the drug (TamR). Breast Tumour Kinase (BRK), a tyrosine kinase, presents itself
as a possible target to combat TamR resistance as it drives tumourigenesis in breast cancer cells.
Previous research has shown that BRK knockdown re-sensitizes TamR cells to the drug, though
the mechanisms behind BRKās functioning in TamR have yet to be elucidated. To address this, I
used a global phosphoproteomics approach to compare MCF7 cell lines, that differed in their
sensitivity to Tamoxifen, and TamR T47D cells, that differed in BRK expression, and found a total
of 1048 differentially expressed phosphopeptides. Pathway analysis revealed overrepresentation
of the IGFR and insulin receptor signaling in both MCF7 and T47D TamR cells as well as when
BRK was knocked down in T47D TamR cells. Specifically, BRK knockdown resulted in the
inhibition of Insulin Receptor Substrate-1 (IRS1) through the hyperphosphorylation of the S1101
site and the hypophosphorylation of the Y896. Subsequent RT-PCR and ChIP-qPCR analyses
revealed that both BRK knockdown and inhibition reduced downstream changes in cyclin D1 gene
expression mediated by IRS1. To further identify BRK-specific targets, phosphotyrosine-enriched
phosphoproteomics analysis was also conducted, comparing T47D Parental, T47D TamR and
T47D TamR BRK knockdown cells. Out of 6492 phosphosites identified, 118 high -confidence
phosphotyrosine sites were analyzed for significant changes in phosphorylation levels to identify
differentially regulated pathways in TamR versus Parental cells and changes in these pathways
when BRK is knocked down in TamR. Total proteomics analysis was then used to calculate the
phosphorylation levels of these peptides relative to their total levels. Through this, I identified
potential BRK-specific targets involved in TamR such as CDK1, GSK3-beta and catenin delta-1.
Of these targets, I was able to validate that both the knockdown and inhibition of BRK in TamR
cells resulted in the hypophosphorylation of both CDK1 and catenin delta-1 at the Y15 and Y904
phosphosites respectively. Overall, these findings indicate that BRK helps regulate TamR through
its interaction with signaling intermediaries in the IGFR/insulin receptor signaling pathway
Field-level rice yield estimations under different farm practices using the crop simulation model for better yield
Crop yield estimation is essential for decision-making systems and insurance policy makers. Numerous methodologies for yield estimation have been developed, encompassing crop models, remote sensing techniques, and empirical equations. Each approach holds unique limitations and advantages. The primary aim of this study was to assess the accuracy of the DSSAT (Decision Support System for Agro Technology Transfer) model in predicting rice yields and LAI (Leaf Area Index) across various management methods. Additionally, the study sought to identify the optimal management practice forĀ attainingĀ higher yields. Crop models facilitate the expeditious evaluation of management strategies aimed at improving crop yield and analyzing the balance between production, resource efficiency, and environmental impacts. The study region selected for analysis is Karimnagar district of Telangana state. DSSAT has been chosen as the preferred tool due to its high efficiency in evaluating crop yield. The model's simulated yield was compared to the observed yield obtained from crop-cutting experiments. The results indicate a correlation of 0.81 and 0.85 between observed and simulated yields, as well as between model LAI and yield. An observation was made regarding a discrepancy between predicted and actual yields, which can be attributed to biotic stress. However, it should be noted that the current model does not account for this factor. The observed average yield was 5200 kg ha-1, whereas the projected yield was 5400 kg ha-1. The findings indicate that the model's performance is influenced by both the timing of sowing and the amount of nitrogen applied. The findings indicate that the DSSAT model has demonstrated a high level of accuracy in predicting both yields and leaf area index (LAI) across various management strategies. This study showcases the potential use of crop simulation models as a technology-driven tool to identify the most effective management strategies for rice production
Communication Strategies for Building Climate-Smart Farming Communities
Farming communities across the globe, especially in the drylands of Asia and Africa, are already facing the effects of climate change. With droughts, unseasonal rains and unpredictable dry spells becoming more frequent, reaching farmers with timely climate information and cropping advice is crucial as are coping strategies to face future climate shocks. There is also an urgent need to create, among farming communities, an awareness on reducing agricultural greenhouse gas emissions (GHGs) which contribute to a third of all human-generated GHGs. For this, holistic communication strategies that use best available technologies and target not just farmers but link all the stakeholders along the agricultural value chain are needed. Working for over 40 years in the semi-arid tropics with varied partners, ICRISAT has developed resilient dryland crops and a pool of climate-smart technologies besides researching on biofuels as alternatives for fossil fuels. These technologies are being implemented in locations across sub-Saharan Africa and Southeast Asia. This article records the various approaches used, lessons learnt and successes achieved in building climate smart villages/communes that restore/nurture the environment, use scientific innovations and climate information for cropping decisions, diversify livelihoods, link to markets, influence policy makers and ultimately make agriculture profitable
An FPGA/MPSoC Based Low Latency Onboard SAR Processor
This paper describes the concept and prototype implementation of a low latency spaceborne onboard Synthetic Aperture Radar (SAR) processor runing on a Multi-Processor-System-On-Chip (MPSoC) computing device combining an ARM processor and a Field-Programmable-Gate-Array (FPGA). The SAR processor is designed to generate SAR imagery from TerraSAR-X stripmap data for subsequent ship detection and sea state determination. Low latency data processing is a key development goal. Currently, a raw data block of 8kĆ32k samples, covering 375 km^2 to 500 km^2 , is focused on the hardware within 4 s. Together with an attached level-2 ship detection, wind, and sea state processor, running on the same device, a SAR data processing chain for generation of maritime alerts is formed. This chain is part of a larger prototype system being developed in the frame of the H2020 EO-ALERT project which further comprises an optical data chain, data compression/encryption, and scheduling on multiple reconfigurable MPSoC boards
Delineation of the ancestral tus-dependent replication fork trap
In Escherichia coli, DNA replication termination is orchestrated by two clusters of Ter sites forming a DNA replication fork trap when bound by Tus proteins. The formation of a ālockedā Tusā Ter complex is essential for halting incoming DNA replication forks. However, the absence of replication fork arrest at some Ter sites raised questions about their significance. In this study, we examined the genome-wide distribution of Tus and found that only the six innermost Ter sites (TerAāE and G) were significantly bound by Tus. We also found that a single ectopic insertion of TerB in its non-permissive orientation could not be achieved, advocating against a need for āback-upā Ter sites. Finally, examination of the genomes of a variety of Enterobacterales revealed a new replication fork trap architecture mostly found outside the Enterobacteriaceae family. Taken together, our data enabled the delineation of a narrow ancestral Tus-dependent DNA replication fork trap consisting of only two Ter sites
Copper promoted synthesis of tetrazoles and further conversion into diaryl tetrazoles through C-N cross-coupling approach
313-324Efficient tandem three component method has been demonstrated for the synthesis of substituted tetrazoles under mild reaction conditions using copper catalysis. Green solvent DMSO has been utilized and the reaction has been carried out at room temperature which establishes that our method is green synthetic approach. Variety of substrates readily undergo the optimized reaction conditions to provide their respective target products in good to excellent yields. In addition we have observed regioselective compounds depending on the substituents of phenyl ring. All the reactions are rapid, facile and are accomplished at room temperature. The reactions are of general application, clean and efficient. Furthermore we have confirmed that no other by-products could be identified during our experimental reaction process. In addition, C-N cross-coupling have been developed with phenyltetrazoleamines and aryl iodide under moderate reaction conditions
Forced Symmetry Breaking from SO(3) to SO(2) for Rotating Waves on the Sphere
We consider a small SO(2)-equivariant perturbation of a reaction-diffusion
system on the sphere, which is equivariant with respect to the group SO(3) of
all rigid rotations. We consider a normally hyperbolic SO(3)-group orbit of a
rotating wave on the sphere that persists to a normally hyperbolic
SO(2)-invariant manifold . We investigate the effects of this
forced symmetry breaking by studying the perturbed dynamics induced on
by the above reaction-diffusion system. We prove that depending
on the frequency vectors of the rotating waves that form the relative
equilibrium SO(3)u_{0}, these rotating waves will give SO(2)-orbits of rotating
waves or SO(2)-orbits of modulated rotating waves (if some transversality
conditions hold). The orbital stability of these solutions is established as
well. Our main tools are the orbit space reduction, Poincare map and implicit
function theorem
Selective and potent urea inhibitors of Cryptosporidium parvum inosine 5ā-monophosphate dehydrogenase
Cryptosporidium parvum and related species are zoonotic intracellular parasites of the intestine. Cryptosporidium is a leading cause of diarrhea in small children around the world. Infection can cause severe pathology in children and immunocompromised patients. This waterborne parasite is resistant to common methods of water treatment and therefore a prominent threat to drinking and recreation water even in countries with strong water safety systems. The drugs currently used to combat these organisms are ineffective. Genomic analysis revealed that the parasite relies solely on inosine-5?-monophosphate dehydrogenase (IMPDH) for the biosynthesis of guanine nucleotides. Herein, we report a selective urea-based inhibitor of C. parvum IMPDH (CpIMPDH) identified by high-throughput screening. We performed a SAR study of these inhibitors with some analogues exhibiting high potency (IC50 1000-fold versus human IMPDH type 2 and good stability in mouse liver microsomes. A subset of inhibitors also displayed potent antiparasitic activity in a Toxoplasma gondii model
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