Synthesis and Characterization of Pd/CeO2 Single Atom Catalyst for Oxygen Reduction Reaction

Single-atom catalysts (SACs) have attracted considerable interest for their potential to improve the efficiency of chemical reactions. Here, we report the synthesis and characterization of a Pd/CeO2 SAC for the oxygen reduction reaction (ORR). CeO2 nanocubes as the catalyst support were successfully synthesized and characterized by XRD and TEM. Single atoms (Pd1) were loaded on the nanocubes to create the SAC. It is expected that the Pd/CeO2 SAC would show improved ORR activity compared to the Pd nano-crystalline catalyst, highlighting the potential of SACs for improving catalytic performance. Additionally, this work could pave the way for the extension of this method to other metals and supports, leading to a better understanding of how catalysts can be designed to maximize the ORR performance.https://orb.binghamton.edu/research_days_posters_2023/1081/thumbnail.jp

Variation suggestive of horizontal gene transfer at a lipopolysaccharide (lps) biosynthetic locus in Xanthomonas oryzae pv. oryzae, the bacterial leaf blight pathogen of rice

BACKGROUND: In animal pathogenic bacteria, horizontal gene transfer events (HGT) have been frequently observed in genomic regions that encode functions involved in biosynthesis of the outer membrane located lipopolysaccharide (LPS). As a result, different strains of the same pathogen can have substantially different lps biosynthetic gene clusters. Since LPS is highly antigenic, the variation at lps loci is attributed to be of advantage in evading the host immune system. Although LPS has been suggested as a potentiator of plant defense responses, interstrain variation at lps biosynthetic gene clusters has not been reported for any plant pathogenic bacterium. RESULTS: We report here the complete sequence of a 12.2 kb virulence locus of Xanthomonas oryzae pv. oryzae (Xoo) encoding six genes whose products are homologous to functions involved in LPS biosynthesis and transport. All six open reading frames (ORFs) have atypical G+C content and altered codon usage, which are the hallmarks of genomic islands that are acquired by horizontal gene transfer. The lps locus is flanked by highly conserved genes, metB and etfA, respectively encoding cystathionine gamma lyase and electron transport flavoprotein. Interestingly, two different sets of lps genes are present at this locus in the plant pathogens, Xanthomonas campestris pv. campestris (Xcc) and Xanthomonas axonopodis pv. citri (Xac). The genomic island is present in a number of Xoo strains from India and other Asian countries but is not present in two strains, one from India (BXO8) and another from Nepal (Nepal624) as well as the closely related rice pathogen, Xanthomonas oryzae pv. oryzicola (Xoor). TAIL-PCR analysis indicates that sequences related to Xac are present at the lps locus in both BXO8 and Nepal624. The Xoor strain has a hybrid lps gene cluster, with sequences at the metB and etfA ends, being most closely related to sequences from Xac and the tomato pathogen, Pseudomonas syringae pv. tomato respectively. CONCLUSION: This is the first report of hypervariation at an lps locus between different strains of a plant pathogenic bacterium. Our results indicate that multiple HGT events have occurred at this locus in the xanthomonad group of plant pathogens

Small interfering RNA targeted to stem-loop II of the 5' untranslated region effectively inhibits expression of six HCV genotypes

BACKGROUND: The antiviral action of interferon alpha targets the 5' untranslated region (UTR) used by hepatitis C virus (HCV) to translate protein by an internal ribosome entry site (IRES) mechanism. Although this sequence is highly conserved among different clinical strains, approximately half of chronically infected hepatitis C patients do not respond to interferon therapy. Therefore, development of small interfering RNA (siRNA) targeted to the 5'UTR to inhibit IRES mediated translation may represent an alternative approach that could circumvent the problem of interferon resistance. RESULTS: Four different plasmid constructs were prepared for intracellular delivery of siRNAs targeting the stem loop II-III of HCV 5' UTR. The effect of siRNA production on IRES mediated translation was investigated using chimeric clones between the gene for green fluorescence protein (GFP) and IRES sequences of six different HCV genotypes. The siRNA targeted to stem loop II effectively mediated degradation of HCV IRES mRNA and inhibited GFP expression in the case of six different HCV genotypes, where as siRNAs targeted to stem loop III did not. Furthermore, intracytoplasmic expression of siRNA into transfected Huh-7 cells efficiently degraded HCV genomic RNA and inhibited core protein expression from infectious full-length infectious clones HCV 1a and HCV 1b strains. CONCLUSION: These in vitro studies suggest that siRNA targeted to stem-loop II is highly effective inhibiting IRES mediated translation of the major genotypes of HCV. Stem-loop II siRNA may be a good target for developing an intracellular immunization strategy based antiviral therapy to inhibit hepatitis C virus strains that are not inhibited by interferon

The role of horizontal transfer in the evolution of a highly variable lipopolysaccharide biosynthesis locus in xanthomonads that infect rice, citrus and crucifers

<p>Abstract</p> <p>Background</p> <p>Lipopolysaccharide (LPS) is a pathogen associated molecular pattern (PAMP) of animal and plant pathogenic bacteria. Variation at the interstrain level is common in LPS biosynthetic gene clusters of animal pathogenic bacteria. This variation has been proposed to play a role in evading the host immune system. Even though LPS is a modulator of plant defense responses, reports of interstrain variation in LPS gene clusters of plant pathogenic bacteria are rare.</p> <p>Results</p> <p>In this study we report the complete sequence of a variant 19.9 kb LPS locus present in the BXO8 strain of <it>Xanthomonas oryzae </it>pv. <it>oryzae </it>(Xoo), the bacterial blight pathogen of rice. This region is completely different in size, number and organization of genes from the LPS locus present in most other strains of Xoo from India and Asia. Surprisingly, except for one ORF, all the other ORFs at the BXO8 LPS locus are orthologous to the genes present at this locus in a sequenced strain of <it>X. axonopodis </it>pv. <it>citri </it>(Xac; a pathogen of citrus plants). One end of the BXO8 LPS gene cluster, comprised of ten genes, is also present in the related rice pathogen, <it>X. oryzae </it>pv. <it>oryzicola </it>(Xoc). In Xoc, the remainder of the LPS gene cluster, consisting of seven genes, is novel and unrelated to LPS gene clusters of any of the sequenced xanthomonads. We also report substantial interstrain variation suggestive of very recent horizontal gene transfer (HGT) at the LPS biosynthetic locus of <it>Xanthomonas campestris </it>pv.<it> campestris </it>(Xcc), the black rot pathogen of crucifers.</p> <p>Conclusion</p> <p>Our analyses indicate that HGT has altered the LPS locus during the evolution of <it>Xanthomonas oryzae </it>pathovars and suggest that the ancestor of all <it>Xanthomonas oryzae </it>pathovars had an Xac type of LPS gene cluster. Our finding of interstrain variation in two major xanthomonad pathogens infecting different hosts suggests that the LPS locus in plant pathogenic bacteria, as in animal pathogens, is under intense diversifying selection.</p

MPPT oscillations minimization in PV system by controlling non-linear dynamics in SEPIC DC-DC converter

Solar PV power generation has achieved rapid growth in developing countries which has many merits such as absence of noise, longer life, no pollution, less time for installation, and ease of grid interface. A maximum power point tracking circuit (MPPT) consists of DC-DC power electronics converters that are used to improve the energy attainment from solar PV array. This paper presents a detailed analysis to control of chaos, a non-linear dynamic in SEPIC DC-DC converter interfaced solar PV system, to minimize the oscillations near to MPP. In SEPIC DC-DC converter, the input inductor current is continuous and capable of sweeping the whole I-V curve of a PV module from open circuit voltage (Voc) to short circuit current (Isc) operating points. To trace the true maximum power point and to nullify the oscillations near to MPP, the yield output voltage needs to ensure period-1 operation

A study of association between serum TSH levels and severity of heart failure in subclinical hypothyroidism

Background: Cardiovascular diseases account for most common cause of death in India and world so far. One of the established risk factors for HF is subclinical hypothyroidism. Our study aimed to study the relationship between TSH levels in subclinical hypothyroidism and the clinical severity of HF in patients with pre-existing HF. Methods: This cross-sectional study was conducted in the hospitals attached to Bangalore medical college and research Institute. 51 patients with HF who had subclinical hypothyroidism who satisfied the inclusion criteria were included, Data was collected in the form of history, clinical examination and relevant investigations. Statistical analysis was performed using SPSS software, p&lt;0.05 was considered significant. Results: Out of 51 patients, 70.6% were males and 29.4% were females and majority of the patients (33.3%) were aged 40 to 50 years. 35.3% patients had LV global hypokinesia, 31.4% had LV diastolic dysfunction and 21.6% had RWMA. Chi-square test showed statistically significant association between TSH and RWMA(p=0.00). Out of the 51 patients, NYHA Class-1 were 9.8%, Class-2 were 31.4%, Class-3 were 27.5% and Class-4 were 31.4%. Chi-square test showed no statistically significant association between TSH levels and NYHA class (p=0. 32). Conclusions: There was significant association between features suggestive of cardiac compromise on 2D-echocardiography with subclinical hypothyroidism, but there was no significant association between the severity of HF assessed clinically by NYHA class with subclinical hypothyroidism. Hence, our study couldn’t establish an association between severity of subclinical hypothyroidism on clinical severity of existing HF

A comparative study of effective microorganisms (EM) and biocompost in the decomposition of coconut waste material

Lignocellulosic waste materials are recalcitrant in nature due to their interconnected complex polymer. Hence, composting of this type of lignocellulosic waste material is time consuming. This study aimed to compare the efficiency of effective microorganisms (EM) and biocompost in enhancing the decomposition of coconut waste.. A windrow heap of 3 x 2 x 1.5 m was prepared with alternate layers of coconut waste and cow dung. Two percent of effective microorganisms and biocompost were augment in each heap and the changes in the nutrient status of the compost across different composting time periods (15, 30, 45, 60, 75 and 90 days) were studied. It was observed that augmentation of both effective microorganisms and biocompost significantly reduced the organic carbon, while the total nitrogen, phosphorus and potassium increased on successive days of composting. At the end of study period, application of effective microoganisms (EM) reduced the organic carbon by 30.97%; and recorded the highest total nitrogen (1.20±0.024%), phosphorus (0.21±0.003%) and potassium (1.21±0.016%) content. Furthermore, augmenting effective microorganisms was highly effective, and the compost maturity was attained on the 60th day with a CN ratio of 17.8:1. The compost maturity test also validated that the effective microorganisms were more effective than biocompost in improving the rate of degradation of coconut waste and in producing mature compost of good quality

Investigation of deformation of the cornea during tonometry using FEM

A three dimensional finite element model of the human eye is developed to evaluate the force which will be applied over the surface of cornea during tonometry and gonioscopy tests. The standard tonometers and gonioscopy experiences deformation from 0.5mm to 3mm of the cornea is adopted during both point contact and boundary contact on the surface of the cornea. The results demonstrate the maximum force experienced by the tonometer with point contact at the center of the cornea for the maximum possible deformation of the cornea during tonometry. The study also analyzes for the force experienced by the tonometer or goniolens with boundary layer contact for the defined deformation of the cornea along the direction from cornea towards the retina

Suitability of vetiver (Vetiveria zizanioides) for removal of Cr (III) from tannery effluent using floating bed and rhizofiltration systems

Various physico-chemical methods have been employed in remediating heavy metals from wastewater, but most of them are expensive. While phytoremediation, is one cost-effective and eco-friendly technology, proves to be an alternate amongst which Vetiver, a unique tropical plant, is recognized for its large biomass and dense root system and has been proven for various remediation studies. The current research was conducted to assess the potential for Vetiver rhizofiltration of chromium. A pilot study was conducted in rhizobox wherein Vetiver was grown using sand as a medium and samples were collected from rhizobox port 1 and rhizobox port 2. Subsequently, the study was upscaled to a floating bed experiment. In both studies, Vetiver were grown under 500 mg L-1 Cr (III) solution and tannery effluent had a chromium concentration of 379 mg L-1 and the results were compared to control. Between the samples collected from port 1 and 2, the removal of chromium in port 1 was recorded to be higher than that of port 2. Moreover, the removal of chromium ions from the tannery effluent was relatively higher than the spiked solution. In both the ports, the highest removal of chromium concentration was recorded in T5 (Sand + Vetiver + Cr (III) @ 500 mg kg-1) with a removal percent of 12.59 and 10.38% in port 1 and 2, respectively. Hence, Vetiver grass has a great potential in removing pollutants like chromium from the wastewater.