344 research outputs found
Graphene Ambipolar Multiplier Phase Detector
We report the experimental demonstration of a
multiplier phase detector implemented with a single top-gated
graphene transistor. Ambipolar current conduction in graphene
transistors enables simplification of the design of the multiplier
phase detector and reduces its complexity in comparison to phase
detectors based on conventional unipolar transistors. Fabrication
of top-gated graphene transistors is essential to achieve the higher
gain necessary to demonstrate phase detection. We report a phase
detector gain of −7 mV/rad in this letter. An analysis of key
technological parameters of the graphene transistor, including series
resistance, top-gate insulator thickness, and output resistance,
indicates that the phase detector gain can be improved by as much
as two orders of magnitude.NSF CAREER Award CCF-074685
Synthesis and Structure-Activity Relationships of Pyridoxal-6-arylazo-5'-phosphate and Phosphonate Derivatives as P2 Receptor Antagonists.
Novel analogs of the P2 receptor antagonist pyridoxal-5'-phosphate-6-phenylazo-2',4'-disulfonate (PPADS) were synthesized. Modifications were made through functional group substitution on the sulfophenyl ring and at the phosphate moiety through the inclusion of phosphonates, demonstrating that a phosphate linkage is not required for P2 receptor antagonism. Substituted 6-phenylazo and 6-naphthylazo derivatives were also evaluated. Among the 6-phenylazo derivatives, 5'-methyl, ethyl, propyl, vinyl, and allyl phosphonates were included. The compounds were tested as antagonists at turkey erythrocyte and guinea-pig taenia coli P2Y(1) receptors, in guinea-pig vas deferens and bladder P2X(1) receptors, and in ion flux experiments by using recombinant rat P2X(2) receptors expressed in Xenopus oocytes. Competitive binding assay at human P2X(1) receptors in differentiated HL-60 cell membranes was carried out by using [(35)S]ATP-?-S. A 2'-chloro-5'-sulfo analog of PPADS (C(14)H(12)O(9)N(3)ClPSNa), a vinyl phosphonate derivative (C(15)H(12)O(11)N(3)PS(2)Na(3)), and a naphthylazo derivative (C(18)H(14)O(12)N(3)PS(2)Na(2)), were particularly potent in binding to human P2X(1) receptors. The potencies of phosphate derivatives at P2Y(1) receptors were generally similar to PPADS itself, except for the p-carboxyphenylazo phosphate derivative C(15)H(13)O(8)N(3)PNa and its m-chloro analog C(15)H(12)O(8)N(3)ClPNa, which were selective for P2X vs. P2Y(1) receptors. C(15)H(12)O(8)N(3)ClPNa was very potent at rat P2X(2) receptors with an IC(50) value of 0.82 ?M. Among the phosphonate derivatives, [4-formyl-3-hydroxy-2-methyl-6-(2-chloro-5-sulfonylphenylazo)-pyrid-5-yl]methylphosphonic acid (C(14)H(12)-O(8)N(3)ClPSNa) showed high potency at P2Y(1) receptors with an IC(50) of 7.23 ?M. The corresponding 2,5-disulfonylphenyl derivative was nearly inactive at turkey erythrocyte P2Y(1) receptors, whereas at recombinant P2X(2) receptors had an IC(50) value of 1.1 ?M. An ethyl phosphonate derivative (C(15)H(15)O(11)N(3)PS(2)Na(3)), whereas inactive at turkey erythrocyte P2Y(1) receptors, was particularly potent at recombinant P2X(2) receptors
Systematic Dissection of Roles for Chromatin Regulators in a Yeast Stress Response
Packaging of eukaryotic genomes into chromatin has wide-ranging effects on gene transcription. Curiously, it is commonly observed that deletion of a global chromatin regulator affects expression of only a limited subset of genes bound to or modified by the regulator in question. However, in many single-gene studies it has become clear that chromatin regulators often do not affect steady-state transcription, but instead are required for normal transcriptional reprogramming by environmental cues. We therefore have systematically investigated the effects of 83 histone mutants, and 119 gene deletion mutants, on induction/repression dynamics of 170 transcripts in response to diamide stress in yeast. Importantly, we find that chromatin regulators play far more pronounced roles during gene induction/repression than they do in steady-state expression. Furthermore, by jointly analyzing the substrates (histone mutants) and enzymes (chromatin modifier deletions) we identify specific interactions between histone modifications and their regulators. Combining these functional results with genome-wide mapping of several histone marks in the same time course, we systematically investigated the correspondence between histone modification occurrence and function. We followed up on one pathway, finding that Set1-dependent H3K4 methylation primarily acts as a gene repressor during multiple stresses, specifically at genes involved in ribosome biosynthesis. Set1-dependent repression of ribosomal genes occurs via distinct pathways for ribosomal protein genes and ribosomal biogenesis genes, which can be separated based on genetic requirements for repression and based on chromatin changes during gene repression. Together, our dynamic studies provide a rich resource for investigating chromatin regulation, and identify a significant role for the “activating” mark H3K4me3 in gene repression
Correlation the Breastfeeding Practices of Mothers in Relation to the Factors Influencing Breast Feeding
Children are regarded as a divine gift, and as guardians, it is our responsibility to fulfil their needs. The presence of children brings joy and purpose to our lives. Parents bear the responsibility of providing proper nourishment, love, and attention, and ensuring good health for their children. Mother\u27s milk is recognized as the optimal food for infants and is considered the fundamental right of every child. This study aimed to explore the correlation between breastfeeding practices among mothers and the factors influencing these practices. This study employed a cross-sectional descriptive design and was conducted in the Department of Pediatrics at Meenakshi Medical College Hospital and Research Institute, Kanchipuram, which adheres to the baby-friendly hospital initiative. The sample size comprised 210 patients, and data were collected using a pre-designed questionnaire. Questions were presented to mothers in their native language, and their responses were recorded in English. The majority of mothers in this study fell within the age group of 21 to 25 years, with 7% being literate. A significant number of mothers identified as homemakers. Age, education, occupation, economic status, religion, and family type were identified as significant factors associated with mothers\u27 knowledge and attitudes toward exclusive breastfeeding. The findings revealed that exclusive breastfeeding practices remain low within the community. To address this, creating awareness through health education on breastfeeding practices among mothers is crucial. Such efforts can serve as a protective shield, guarding infants from malnutrition and infections
A Clinical and Bacteriological Study of Acute Diarrhea in Children with Special Reference to Serum Electrolyte
Aim and Background: Diarrhea is major public health problem in developing countries. An estimated 1.8 billion episodes of diarrhea occur each year and million children under the age of 5 years die of diarrhea , 80 percent of these deaths affect children under the age of two years. The episodes are generally associated with other infectious diseases, making treatment and prevention more difficult. Materials and Methods: Children under 5 years of age with history of diarrhea of less than 14 days duration admitted to the pediatric wards in Meenakshi Medical College Hospital and Research Institute. Methods of collection of data`s by direct questioning and examination of the study group children. Results: In the present study the maximum number of cases belong to the age group of 7-12 months (33%), and the incidence of diarrhea below 2 years was 87%. Conclusion: In the present study we conclude that the Bacteriological study and sensitivity pattern helps us to identify the most prevalent organism in the locality and to select the most appropriate drug and thus reducing the cost of treatment, lsonatremic dehydration was the commonest
Project #31: Reducing Greenhouse Gas Emissions in Jackson: A CQI Story about the Triumphs of Science and Collaboration in Changing Clinical Operations
The climate change crisis threatens human health by adversely affecting the spread of infectious disease, malnutrition, mental health, and the displacement of people or communities. The Anesthesiology Performance Improvement and Reporting Exchange (ASPIRE) is a project of the Multicenter Perioperative Outcomes Group (MPOG) Collaborative Quality Initiative (CQI). Their sustainability goal is to help reduce greenhouse gas emissions from anesthesia waste used in the US by optimizing environmentally-safer anesthesia agents and managing fresh gas flow.https://scholarlycommons.henryford.com/qualityexpo2024/1033/thumbnail.jp
5G-Based Multi-Sensor Platform for Monitoring of Workpieces and Machines: Prototype Hardware Design and Firmware
In this paper, we introduce a 5G-based multi-sensor platform for monitoring workpieces and machines. The prototype is realized within the EU-funded 5G-SMART project, which aims to enable smart manufacturing through 5G, demonstrating and validating new generation network technology in industrial processes. There are already state-of-the-art solutions, but with drawbacks such as limited flexibility, brief real-time capability, and sensors aimed at single applications. The 5G-SMART multi-sensor platform is designed to overcome these points and meet the requirements of Industry 4.0. The device is equipped with different sensors to acquire multiple data from workpieces and machines of the shop floor, wirelessly connected by 5G to the factory cloud. A hardware design description of the prototype is provided, focusing on the electronic components and their interaction with the microcontroller. Verification of the correct functioning of the board is given, with a basic library for the main peripherals used as a basis for the final firmware
Heterogeneous electrocatalysis in porous cathodes of solid oxide fuel cells
A general physics-based model is developed for heterogeneous electrocatalysis
in porous electrodes and used to predict and interpret the impedance of solid
oxide fuel cells. This model describes the coupled processes of oxygen gas
dissociative adsorption and surface diffusion of the oxygen intermediate to the
triple phase boundary, where charge transfer occurs. The model accurately
captures the Gerischer-like frequency dependence and the oxygen partial
pressure dependence of the impedance of symmetric cathode cells. Digital image
analysis of the microstructure of the cathode functional layer in four
different cells directly confirms the predicted connection between geometrical
properties and the impedance response. As in classical catalysis, the
electrocatalytic activity is controlled by an effective Thiele modulus, which
is the ratio of the surface diffusion length (mean distance from an adsorption
site to the triple phase boundary) to the surface boundary layer length (square
root of surface diffusivity divided by the adsorption rate constant). The
Thiele modulus must be larger than one in order to maintain high surface
coverage of reaction intermediates, but care must be taken in order to
guarantee a sufficient triple phase boundary density. The model also predicts
the Sabatier volcano plot with the maximum catalytic activity corresponding to
the proper equilibrium surface fraction of adsorbed oxygen adatoms. These
results provide basic principles and simple analytical tools to optimize porous
microstructures for efficient electrocatalysis
A Quantitative, High-Throughput Reverse Genetic Screen Reveals Novel Connections between Pre–mRNA Splicing and 5′ and 3′ End Transcript Determinants
Here we present the development and implementation of a genome-wide reverse genetic screen in the budding yeast, Saccharomyces cerevisiae, that couples high-throughput strain growth, robotic RNA isolation and cDNA synthesis, and quantitative PCR to allow for a robust determination of the level of nearly any cellular RNA in the background of 5,500 different mutants. As an initial test of this approach, we sought to identify the full complement of factors that impact pre–mRNA splicing. Increasing lines of evidence suggest a relationship between pre–mRNA splicing and other cellular pathways including chromatin remodeling, transcription, and 3′ end processing, yet in many cases the specific proteins responsible for functionally connecting these pathways remain unclear. Moreover, it is unclear whether all pathways that are coupled to splicing have been identified. As expected, our approach sensitively detects pre–mRNA accumulation in the vast majority of strains containing mutations in known splicing factors. Remarkably, however, several additional candidates were found to cause increases in pre–mRNA levels similar to that seen for canonical splicing mutants, none of which had previously been implicated in the splicing pathway. Instead, several of these factors have been previously implicated to play roles in chromatin remodeling, 3′ end processing, and other novel categories. Further analysis of these factors using splicing-sensitive microarrays confirms that deletion of Bdf1, a factor that links transcription initiation and chromatin remodeling, leads to a global splicing defect, providing evidence for a novel connection between pre–mRNA splicing and this component of the SWR1 complex. By contrast, mutations in 3′ end processing factors such as Cft2 and Yth1 also result in pre–mRNA splicing defects, although only for a subset of transcripts, suggesting that spliceosome assembly in S. cerevisiae may more closely resemble mammalian models of exon-definition. More broadly, our work demonstrates the capacity of this approach to identify novel regulators of various cellular RNAs
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