170 research outputs found
Effect of Benzene and Ethylbenzene on the Transcription of methyl-\u3cem\u3etert\u3c/em\u3e-butyl Ether Degradation Genes of \u3cem\u3eMethylibium petroleiphilum\u3c/em\u3e PM1
Methyl-tert-butyl ether (MTBE) and its degradation by-product, tert-butyl alcohol (TBA), are widespread contaminants detected frequently in groundwater in California. Since MTBE was used as a fuel oxygenate for almost two decades, leaking underground fuel storage tanks are an important source of contamination. Gasoline components such as BTEX (benzene, toluene, ethylbenzene and xylenes) are often present in mixtures with MTBE and TBA. Investigations of interactions between BTEX and MTBE degradation have not yielded consistent trends, and the molecular mechanisms of BTEX compoundsâ impact on MTBE degradation are not well understood. We investigated trends in transcription of biodegradation genes in the MTBE-degrading bacterium, Methylibium petroleiphilum PM1 upon exposure to MTBE, TBA, ethylbenzene and benzene as individual compounds or in mixtures. We designed real-time quantitative PCR assays to target functional genes of strain PM1 and provide evidence for induction of genes mdpA (MTBE monooxygenase), mdpJ (TBA hydroxylase) and bmoA (benzene monooxygenase) in response to MTBE, TBA and benzene, respectively. Delayed induction of mdpA and mdpJ transcription occurred with mixtures of benzene and MTBE or TBA, respectively. bmoA transcription was similar in the presence of MTBE or TBA with benzene as in their absence. Our results also indicate that ethylbenzene, previously proposed as an inhibitor of MTBE degradation in some bacteria, inhibits transcription of mdpA, mdpJ and bmoAgenes in strain PM1
Gene \u3cem\u3emdpC\u3c/em\u3e Plays a Regulatory Role in the Methyl-\u3cem\u3etert\u3c/em\u3e-butyl Ether Degradation Pathway of \u3cem\u3eMethylibium petroleiphilum\u3c/em\u3e Strain PM1
Among the few bacteria known to utilize methyl tert-butyl ether (MTBE) as a sole carbon source, Methylibium petroleiphilum PM1 is a well-characterized organism with a sequenced genome; however, knowledge of the genetic regulation of its MTBE degradation pathway is limited. We investigated the role of a putative transcriptional activator gene, mdpC, in the induction of MTBE-degradation genes mdpA (encoding MTBE monooxygenase) and mdpJ (encoding tert-butyl alcohol hydroxylase) of strain PM1 in a gene-knockout mutant mdpCâ. We also utilized quantitative reverse transcriptase PCR assays targeting genes mdpA, mdpJ and mdpC to determine the effects of the mutation on transcription of these genes. Our results indicate that gene mdpC is involved in the induction of both mdpA and mdpJ in response to MTBE and tert-butyl alcohol (TBA) exposure in PM1. An additional independent mechanism may be involved in the induction of mdpJ in the presence of TBA
Generation of High Spatial Resolution Terrestrial Surface from Low Spatial Resolution Elevation Contour Maps via Hierarchical Computation of Median Elevation Regions
We proposed a simple yet effective morphological approach to convert a sparse
Digital Elevation Model (DEM) to a dense Digital Elevation Model. The
conversion is similar to that of the generation of high-resolution DEM from its
low-resolution DEM. The approach involves the generation of median contours to
achieve the purpose. It is a sequential step of the I) decomposition of the
existing sparse Contour map into the maximum possible Threshold Elevation
Region (TERs). II) Computing all possible non-negative and non-weighted Median
Elevation Region (MER) hierarchically between the successive TER decomposed
from a sparse contour map. III) Computing the gradient of all TER, and MER
computed from previous steps would yield the predicted intermediate elevation
contour at a higher spatial resolution. We presented this approach initially
with some self-made synthetic data to show how the contour prediction works and
then experimented with the available contour map of Washington, NH to justify
its usefulness. This approach considers the geometric information of existing
contours and interpolates the elevation contour at a new spatial region of a
topographic surface until no elevation contours are necessary to generate. This
novel approach is also very low-cost and robust as it uses elevation contours.Comment: 11 pages, 6 figures,1 table, 1 algorith
Role of cervical length evaluation with transvaginal ultrasound for prediction of preterm delivery in low risk pregnancy
Background: Preterm birth possess a major health burden to the society due to its long - term morbidity, perinatal mortality and high financial expenditures associated with it. Transvaginal ultrasonographic measurement is an effective and objective way of measuring the cervical length. Cervical length <25 mm is considered as the best cervical parameter with a good predictive accuracy for preterm birth. This study was taken up to study the role of cervical length measurement in predicting preterm labor by Trans vaginal sonography (TVS) and to measure cervical length and follow up cases to study the fetal outcome.Methods: Sagital long-axis view of endocervical canal along the entire length was obtained with high frequency endovaginal probe and the length of cervix from external to the internal os was measured. Atleast three measurements were obtained and the best shortest measurement in millimeters was recorded. Transfundal pressure was applied for 15 seconds and cervical length was obtained again. The cases are followed till delivery and outcome is noted.Results: Out of 134 study group of low risk women, 5.9% women and 50% of the women with short cervical length (<25 mm) had preterm birth. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of our study are 75%, 95.2%, 50%, 98.4%, 94% respectively. Among the 134 newborns, majority of the admissions (14) were due to birth asphyxia followed by meconium aspiration syndrome.Conclusions: TVS is a useful technique in assessing the cervical changes during pregnancy and predicting the preterm birth especially when performed between 16-24 weeks of gestational age could identify all the women having short cervical length along with other changes of cervix
Delays in Liquidated and Resolved Firms
The ultimate objective of the Indian bankruptcy reform is to get up to plausible recovery rates and change the behavior of borrowers. The key tool for achieving these objectives is reducing the delay. In the existing literature, we know that there are large delays, particularly for large firms (Bhatia et. al. 2019, Felman et. al. 2019, Shah 2018). The most important proximate objective of the Indian bankruptcy reform is to reduce delays in the bankruptcy process (Shah and Thomas, 2018)
Graphene Oxide-Based Memristor
A memristor is the memory extension to the concept of resistor. With unique superior properties, memristors have prospective promising applications in nonâvolatile memory (NVM). Resistive random access memory (RRAM) is a nonâvolatile memory using a material whose resistance changes under electrical stimulus can be seen as the most promising candidate for next generation memory both as embedded memory and a standâalone memory due to its high speed, long retention time, low power consumption, scalability and simple structure. Among carbonâbased materials, graphene has emerged as wonder material with remarkable properties. In contrast to metallic nature of graphene, the graphene oxide (GO) is good insulating/semiconducting material and suitable for RRAM devices. The advantage of being atomically thin and the two-dimensional of GO permits scaling beyond the current limits of semiconductor technology, which is a key aspect for highâdensity fabrication. Graphene oxideâbased resistive memory devices have several advantages over other oxide materials, such as easy synthesis and costâeffective device fabrication, scaling down to few nanometre and compatibility for flexible device applications. In this chapter, we discuss the GOâbased RRAM devices, which have shown the properties of forming free, thermally stable, multiâbit storage, flexible and high on/off ratio at low voltage, which boost up the research and development to accelerate the GOâbased RRAM devices for future memory applications
Study to determine serum vitamin D levels in patients with congestive heart failure
Background: It was to evaluate the association of serum levels of vitamin D in patients with congestive heart failure.Methods: The present study was conducted in the department of Medicine at Chattrapati Shivaji Subharti Hospital among 100 patients, aged 18 years and above diagnosed as congestive heart failure on the basis of clinical and echocardiographic evidence. Clinical manifestations looked for CHF were: Dyspnea, orthopnea, acute pulmonary edema, cerebral symptoms, cheyne-stokes respiration, cyanosis, sinus tachycardia, raised jugular venous pressure, congestive hepatomegaly and pedal edema. In the present study deficiency/ insufficiency of vitamin D was considered when the presence of levels of 25-hydroxyvitamin D was 30 respectively with statistically significant difference. The Mean±SD scores of CPK MB (IU/L) was found to be 33.1±20.8 and 18.6±13.3 among the subjects having vitamin D levels 30 respectively with statistically significant difference.Conclusions: The results of the present study suggest that low levels of vitamin D may adversely affect the cardiovascular system
Double Perovskite Sr2FeMoO6: A Potential Candidate for Room Temperature Magnetoresistance Device Applications
The family of double perovskites first received attention in the 1960s, but the discovery of low field magnetoresistnace (LFMR) and half metallicity of the Sr2FeMoO6 (SFMO) compound was made by Kobayashi et al. in 1998. A fully spin polarized half-metal SFMO (Tc > 400) with excellent magnetoresistance response relatively at small applied fields and high temperatures makes SFMO an ideal candidate for room temperature spintronics applications. Primarily, most of the research work on double perovskites SFMO has been focused on bulk ceramic samples and aimed to understand their structural, magnetic, and magnetotransport properties, along with correlation among them. A material such as SFMO that exhibits a large decrease in resistivity and magnetically order well above room temperature is necessary for the advancement of spintronic devices. If the bulk properties observed could be reproduced in thin films, industrially produced SFMO-based spintronic devices could become a reality. Therefore, the purpose of this chapter is to present the detailed background and descriptions of the double perovskite Sr2FeMoO6 (SFMO) thin films and heterostructures with main emphasis to improve or achieve room temperature magnetoresistance properties especially for room temperature magnetoresistive device applications
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Non-Polar and Complementary Resistive Switching Characteristics in Graphene Oxide devices with Gold Nanoparticles: Diverse Approach for Device Fabrication.
Downscaling limitations and limited write/erase cycles in conventional charge-storage based non-volatile memories stimulate the development of emerging memory devices having enhanced performance. Resistive random-access memory (RRAM) devices are recognized as the next-generation memory devices for employment in artificial intelligence and neuromorphic computing, due to their smallest cell size, high write/erase speed and endurance. Unipolar and bipolar resistive switching characteristics in graphene oxide (GO) have been extensively studied in recent years, whereas the study of non-polar and complementary switching is scarce. Here we fabricated GO-based RRAM devices with gold nanoparticles (Au Nps). Diverse types of switching behavior are observed by changing the processing methods and device geometry. Tri-layer GO-based devices illustrated non-polar resistive switching, which is a combination of unipolar and bipolar switching. Five-layer GO-based devices depicted complementary resistive switching having the lowest current values ~12â”A; and this structure is capable of resolving the sneak path issue. Both devices show good retention and endurance performance. Au Nps in tri-layer devices assisted the conducting path, whereas in five-layer devices, Au Nps layer worked as common electrodes between co-joined cells. These GO-based devices with Au Nps comprising different configuration are vital for practical applications of emerging non-volatile resistive memories
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