22 research outputs found
Responding to Agency Avoidance of OIRA
Concerns have recently been raised that US federal agencies may sometimes avoid regulatory review by the White House Office of Information and Regulatory Affairs (OIRA). In this article, we assess the seriousness of such potential avoidance, and we recommend a framework for evaluating potential responses. After summarizing the system of presidential regulatory oversight through OIRA review, we analyze the incentives for agencies to cooperate with or avoid OIRA. We identify a wider array of agency avoidance tactics than has past scholarship, and a wider array of corresponding response options available to OIRA, the President, Congress, and the courts. We argue that, because the relationship between agencies and OIRA involves ongoing repeat player interactions, some of these avoidance tactics are less likely to occur (or to succeed) than has previously been alleged, and others are more likely; the difference depends significantly on how easy it is for OIRA to detect avoidance, and for OIRA, the courts, and others to respond. Further, we note that in this repeat player relationship, responses to agency avoidance tactics may induce further strategic moves and countermoves. Thus we further argue that the optimal response may not always be to try to eliminate the avoidance behavior; some avoidance may be worth tolerating where the benefits of trying to reduce agency avoidance would not justify the costs of response options and countermoves. We therefore conclude that responses to agency avoidance should be evaluated in a way similar to what OIRA asks of agencies evaluating proposed regulations: by weighing the pros and cons of alternative response options (including no action)
Surgical Complications of Arteriovenous Fistula as Permanent Vascular Access in Patients with End Stage Renal Disease at Gezira Hospital for Renal Disease and Surgery. Revisited
Background: Vascular access (VA) is a mainstay to perform an efficient hemodialysis (HD) procedure.
Objectives: To evaluate the surgical complications of AV fistula as permanent vascular access in a patient of end stage renal disease (ESRDS) at Gezira hospital for renal diseases and surgery (GHRDS).
Methods: Retrospective, prospective cross sectional hospital based study, done in 237 patients with end stage renal disease who underwent arteriovenous fistula.In 206 patients of the study sample done retrospectively and 31 patients of the study sample done prospectively,and they were followed for 1year. Study was conducted from September 2010 to September 2016. Data was collected using questionnaire.
Results: Sixty eight percent of study sample were males, with 42% above 50 years and 0.8% less than 10 years. Most of the patients (52.3%) were diagnosed as ESRD from the first presentation, 43.5% were diagnosed as chronic renal failure (CRF) on regular followup, while the minor rest of the patients were due to acute renal failure(ARF) which progressed to end stage renal disease.The complications rate was 32.8% (n=82), perioperative complications were 9.3% (n=22) represented as infections 3.8% (n=9), bleeding 3.0% (n=7), stenosis 1.7% (n=4), thrombosis 0.8% (n=2). The late complications were 23.18% (n= 60) the commonest was pseudo aneurysmal 19.4% (n=46) followed by venous HTN 0.8% (n=2) and steal syndrome 0.4%(n=1), skin necrosis 0.4%(n=1), idiopathic stop function 2.1% (n=5), thrombosis 0.4% (n=1).
Conclusion: Permanent arteriovenous fistula is the best option for haemodialysis in patients with end stage renal disease. The commonest complication was puncture site pseudo aneurysm
Habit-modifying additives and their morphological consequences on photoluminescence and glucose sensing properties of ZnO nanostructures, grown via aqueous chemical synthesis
Incorporating β-Cyclodextrin with ZnO Nanorods: A Potentiometric Strategy for Selectivity and Detection of Dopamine
We describe a chemical sensor based on a simple synthesis of zinc oxide nanorods (ZNRs) for the detection of dopamine molecules by a potentiometric approach. The polar nature of dopamine leads to a change of surface charges on the ZNR surface via metal ligand bond formation which results in a measurable electrical signal. ZNRs were grown on a gold-coated glass substrate by a low temperature aqueous chemical growth (ACG) method. Polymeric membranes incorporating β-cyclodextrin (β-CD) and potassium tetrakis (4-chlorophenyl) borate was immobilized on the ZNR surface. The fabricated electrodes were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The grown ZNRs were well aligned and exhibited good crystal quality. The present sensor system displays a stable potential response for the detection of dopamine in 10−2 mol·L−1 acetic acid/sodium acetate buffer solution at pH 5.45 within a wide concentration range of 1 × 10−6 M–1 × 10−1 M, with sensitivity of 49 mV/decade. The electrode shows a good response time (less than 10 s) and excellent repeatability. This finding can contribute to routine analysis in laboratories studying the neuropharmacology of catecholamines. Moreover, the metal-ligand bonds can be further exploited to detect DA receptors, and for bio-imaging applications
Chemically Modified Metal Oxide Nanostructures Electrodes for Sensing and Energy Conversion
The goal of this thesis is the development of scalable, low cost synthesis of metal oxide nanostructures based electrodes and to correlate the chemical modifications with their energy conversion performance. Methods in energy conversion in this thesis have focused on two aspects; a potentiometric chemical sensor was used to determine the analytical concentration of some components of the analyte solution such as dopamine, glucose and glutamate molecules. The second aspect is to fabricate a photo-electrochemical (PEC) cell. The biocompatibility, excellent electro-catalytic activities and fast electron transfer kinetics accompanied with a high surface area to volume ratio; are properties of some metal oxide nanostructures that of a potential for their use in energy conversion. Furthermore, metal oxide nanostructures based electrode can effectively be improved by the physical or a chemical modification of electrode surface. Among these metal oxide nanostructures are cobalt oxide (Co3O4), zinc oxide (ZnO), and bismuth-zincvanadate (BiZn2VO6) have all been studied in this thesis. Metal oxide nanostructures based electrodes are fabricated on gold-coated glass substrate by low temperature (< 100 0C) wet chemicalapproach. X-ray diffraction, x-ray photoelectron spectroscopy and scanning electron microscopy were used to characterize the electrodes while ultraviolet-visible absorption and photoluminescence were used to investigate the optical properties of the nanostructures. The resultant modified electrodes were tested for their performance as chemical sensors and for their efficiency in PEC activities. Efficient chemically modified electrodes were demonstrated through doping with organic additives like anionic, nonionic or cationic surfactants. The organic additives are showing a crucial role in the growth process of metal oxide nanocrystals and hence can beused to control the morphology. These organic additives act also as impurities that would significantly change the conductivity of the electrodes. However, no organic compounds dependence was observed to modify the crystallographic structure. The findings in this thesis indicate the importance of the use of controlled nanostructures morphology for developing efficient functional materials
Synthesis of Co3O4 Cotton-Like Nanostructures for Cholesterol Biosensor
The use of templates to assist and possess a control over the synthesis of nanomaterials has been an attractive option to achieve this goal. Here we have used sodium dodecyl sulfate (SDS) to act as a template for the low temperature synthesis of cobalt oxide (Co3O4) nanostructures. The use of SDS has led to tune the morphology, and the product was in the form of "cotton-like" nanostructures instead of connected nanowires. Moreover, the variation of the amount of the SDS used was found to affect the charge transfer process in the Co3O4. Using Co3O4 synthesized using the SDS for sensing of cholesterol was investigated. The use of the Co3O4 synthesized using the SDS was found to yield an improved cholesterol biosensor compared to Co3O4 synthesized without the SDS. The improvement of the cholesterol sensing properties upon using the SDS as a template was manifested in increasing the sensitivity and the dynamic range of detection. The results achieved in this study indicate the potential of using template assisted synthesis of nanomaterials in improving some properties, e. g., cholesterol sensing
Fabrication of Sensitive Potentiometric Cholesterol Biosensor Based on Co3O4 Interconnected Nanowires
Highly sensitive, selective, reliable and inexpensive cholesterol biosensors are highly demanded for the routine monitoring of cholesterol molecules in order to prevent heart failure incidents. In this study, Co3O4 nanostructures are synthesized using polyvinyl pyrrolidone surfactant as growth template by a low temperature aqueous chemical growth method. The morphology of nanostructures was investigated by scanning electron microscopy and X-ray diffraction techniques. The nanostructures exhibit interconnected nanowires like morphology with interconnected network of nanowires. The nanostructures of Co3O4 are polycrystalline. The cholesterol oxidase was physically adsorbed on the interconnected nanowires of Co3O4 for the chemical sensing of cholesterol molecules. The sensor device detected a wide range of cholesterol from 1×10−7 M to 1×10−3 M concentrations with sensitivity of −94.031 mV/decade. A detection limit of 0.035×10−7 M cholesterol concentration was observed and a fast response time of 10 s was also noticed. The fabricated device is highly stable, selective, sensitive, reproducible and repeatable. All the collected information about presented cholesterol biosensor indicates its potential application for the monitoring of cholesterol concentrations from human blood serum and real-life samples
Dopamine wide range detection sensor based on modified Co3O4 nanowires electrode
Ultra-thin cobalt oxide (Co3O4) nanowires grown on gold coated glass substrates by the hydrothermal chemical deposition and have been used as a wide range dopamine potentiometric sensor. An anionic surfactant ( sodium dodecylbenzenesulfonate) was used to achieve assisted growth procedure. Moreover, a polymeric membrane containing polyvinyl chloride as plasticized polymer, p-cyclodextrin as ionophore, and potassium tetrakis (4-chlorophenyl) borate as ionic additive were immobilized on the Co3O4 nanostructures through electrostatic adsorption method. X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy were used to characterize the electrodes while ultraviolet-visible absorption was used to investigate the band gap of the Co3O4 nanostructures. The structural characterization showed a cubic crystalline, pure phase, and nanowires morphology of the Co3O4. However, the morphology is altered when the surfactant concentration has been changed. The Co3O4 chemical modified electrodes were used in potentiometric measurements for dopamine in a 10(-2) M acetic acid/sodium acetate solution having a pH of 5.45. For dopamine range from 10(-9) M to 10(-2) M, the potential response of the sensor electrode was linear with a slope of 52 mV/decade. The wide range and high sensitivity of the modified Co3O4 nanowires based sensor for dopamine is attributed to the defects on the metal oxide that is dictated by the used surfactant along with the high surface area-to-volume ratio
Photocatalytic properties for different metal-oxide nanomaterials
We here demonstrate the synthesis of different nanostructures, including nanoparticles, nanorods, core-shell structures,and compound metal oxide nanostructures all synthesized by a low temperature chemical process. We furtherinvestigated their photocatalytic properties for degradation of toxic waste and their photochemical efficiency for watersplitting. All the photocatalytic properties as well as the photochemical properties were utilized using sun radiation. Theresults presented indicate huge potential for the investigated processes with positive impact to energy consumption andbenefits for the environment.Funding agencies: Knut and Alice Wallenberg foundation (KAW), through a Wallenberg Scholar grant; China Scholarship CouncilChina Scholarship Council</p