Investigation of the one-step electrochemical deposition of graphene oxide-doped poly(3,4-ethylenedioxythiophene)-polyphenol oxidase as a dopamine sensor.

In this paper, we fabricated poly(3,4-ethylenedioxythiophene) (PEDOT)-graphene oxide-polyphenol oxidase (PEDOT-GO-PPO) as a dopamine sensor. The morphology of PEDOT-GO-PPO was observed using scanning electron microscopy. Cyclic voltammetry was conducted to study the oxidation-reduction characteristics of dopamine. To optimize the pH, potential and limit of detection of dopamine, the amperometric technique was employed. The found limit of detection was 8 × 10-9 M, and the linear range was from 5 × 10-8 to 8.5 × 10-5 M. The Michaelis-Menten constant (K m) was calculated to be 70.34 µM, and the activation energy of the prepared electrode was 32.75 kJ mol-1. The electrode shows no significant change in the interference study. The modified electrode retains up to 80% of its original activity after 2 months. In the future, the biosensor can be used for the quantification of dopamine in human urine samples. The present modified electrode constitutes a tool for the electrochemical analysis of dopamine.

Enhanced photocatalytic activity of ZnO hexagonal tube/r-GO composite on degradation of organic aqueous pollutant and study of charge transport properties.

ZnO hexagonal tube and ZnO/r-GO nanocomposites were synthesized by hydrothermal method and the nanostructures were characterized by XRD, UV-DRS, PL, FTIR, FESEM, and TEM techniques. The main violet emission peak of the synthesized nanostructures is due to the transition between interstitial zinc and hole (valence band) of ZnO. The potential of ZnO/r-GO nanocomposite was evaluated using methyl orange (MO) and rhodamine-B (RhB), and the results were compared with the activity of synthesized ZnO nanostructures. More than 95% of MO and RhB were by ZnO/r-GO nanocomposite and it was found to be higher than that of ZnO hexagonal tube. The degradation MO and RhB were found to follow first-order kinetics and it has a rate constant of 7.68 × 10-2and 7.83 × 10-2 min-1, respectively. These results are mainly due to the enhanced charge transport property. Trapping experiments show that superoxide radical anion and hydroxide radicals are chief species responsible for the degradation of MO and RhB. The chemical stability of the nanocomposite was evaluated by cycle test experiments and it reveals that the catalyst can be reused up to few cycles without considerable loss of photocatalytic activity. This work affords a simple stratagem to integrate ZnO hexagonal tubes and r-GO nanosheets to construct effective catalysts for the degradation of organic compounds.

Investigation of the Tribological Characteristics of Aluminum 6061-Reinforced Titanium Carbide Metal Matrix Composites.

The current trend in the materials engineering sector is to develop newer materials that can replace the existing materials in various engineering sectors in order to be more and more efficient. Therefore, the present research work is aimed at fabricating and determining the physical, mechanical, and dry sliding wear properties of titanium carbide (TiC)-reinforced aluminum alloy (Al6061) metal matrix composites (MMCs). For the study, the Al6061-TiC microparticle-reinforced composites were fabricated via the liquid metallurgy route through the stir casting method, where the reinforcement of the TiC particles into the Al6061 alloy matrix was added in the range of 0 to 8.0 wt.%, i.e., in the steps of 2.0 wt.%. The synthesis procedure followed the investigation of the various mechanical properties of Al6061-TiC MMCs, such as the density and structure, as well as mechanical and dry wear experimentation. The tests performed on the casted Al6061, as well as its TiC composites, were in harmony with ASTM standards. As per the experimental outcome, it can be confirmed that the increase in the weight percentage of TiC into the Al6061 alloy substantially increases the density, hardness, and tensile strength, at the expense of the percentage of elongation. In addition, the dry wear experiments, performed on a pin-on-disc tribometer, showed that the Al6061-TiC MMCs have superior wear-resistance properties, as compared to those of pure Al6061 alloy. Furthermore, optical micrograph (OM), powdered X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), and scanning electron microscopy (SEM) analyses were employed for the developed Al6061-TiC MMCs before and after the fracture and wear test studies. From the overall analysis of the results, it can be observed that the Al6061-TiC composite material with higher TiC reinforcement displays superior mechanical characteristics.

Fine-Mapping of Sorghum Stay-Green QTL on Chromosome10 Revealed Genes Associated with Delayed Senescence.

This study was conducted to dissect the genetic basis and to explore the candidate genes underlying one of the important genomic regions on an SBI-10 long arm (L), governing the complex stay-green trait contributing to post-flowering drought-tolerance in sorghum. A fine-mapping population was developed from an introgression line cross-RSG04008-6 (stay-green) × J2614-11 (moderately senescent). The fine-mapping population with 1894 F2 was genotyped with eight SSRs and a set of 152 recombinants was identified, advanced to the F4 generation, field evaluated with three replications over 2 seasons, and genotyped with the GBS approach. A high-resolution linkage map was developed for SBI-10L using 260 genotyping by sequencing-Single Nucleotide Polymorphism (GBS-SNPs). Using the best linear unpredicted means (BLUPs) of the percent green leaf area (%GL) traits and the GBS-based SNPs, we identified seven quantitative trait loci (QTL) clusters and single gene, mostly involved in drought-tolerance, for each QTL cluster, viz., AP2/ERF transcription factor family (Sobic.010G202700), NBS-LRR protein (Sobic.010G205600), ankyrin-repeat protein (Sobic.010G205800), senescence-associated protein (Sobic.010G270300), WD40 (Sobic.010G205900), CPK1 adapter protein (Sobic.010G264400), LEA2 protein (Sobic.010G259200) and an expressed protein (Sobic.010G201100). The target genomic region was thus delimited from 15 Mb to 8 genes co-localized with QTL clusters, and validated using quantitative real-time (qRT)-PCR.

Synthesis and Characterization of Fe2(MoO4)3Nano-Photocatalyst by Simple Sol-Gel Method.

Ferric molybdate (Fe2(MoO4)3) nanorods (NRs) were successfully synthesized using metal nitrates, citric acid and ethyl cellulose by a simple sol-gel method. Structural, morphological, optical and magnetic properties of the obtained powder were characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectra, high resolution scanning electron microscope (HR-SEM), energy dispersive X-ray (EDX), UV-Visible diffuse reflectance spectra (DRS), photoluminescence (PL) spectra and vibrating sample magnetometer (VSM). XRD results indicated that the resultant powder was pure single phase crystalline with monoclinic structure. FT-IR spectra indicate the type of bonds between metals and oxygen. HR-SEM images shows that the morphology of the powder consist with well defined nanorods (NRs) structure. VSM results showed ferromagnetic behavior. The addition of TiO2 catalyst, it enhanced the photo-catalytic activity of Fe2(MoO4)3. The mixed oxide catalyst of Fe2(MoO4)3-TiO2 nano-composites (NCs) were also tested for the photocatalytic degradation (PCD) of 4-chlorophenol (4-CP). It was found that the PCD efficiency of Fe2(MoO4)3 NCs is higher than pure Fe2(MoO4)3 and TiO2 catalysts.

Assessment of genetic diversity in the sorghum reference set using EST-SSR markers.

Selection and use of genetically diverse genotypes are key factors in any crop breeding program to develop cultivars with a broad genetic base. Molecular markers play a major role in selecting diverse genotypes. In the present study, a reference set representing a wide range of sorghum genetic diversity was screened with 40 EST-SSR markers to validate both the use of these markers for genetic structure analyses and the population structure of this set. Grouping of accessions is identical in distance-based and model-based clustering methods. Genotypes were grouped primarily based on race within the geographic origins. Accessions derived from the African continent contributed 88.6 % of alleles confirming the African origin of sorghum. In total, 360 alleles were detected in the reference set with an average of 9 alleles per marker. The average PIC value was 0.5230 with a range of 0.1379-0.9483. Sub-race, guinea margaritiferum (Gma) from West Africa formed a separate cluster in close proximity to wild accessions suggesting that the Gma group represents an independent domestication event. Guineas from India and Western Africa formed two distinct clusters. Accessions belongs to the kafir race formed the most homogeneous group as observed in earlier studies. This analysis suggests that the EST-SSR markers used in the present study have greater discriminating power than the genomic SSRs. Genetic variance within the subpopulations was very high (71.7 %) suggesting that the germplasm lines included in the set are more diverse. Thus, this reference set representing the global germplasm is an ideal material for the breeding community, serving as a community resource for trait-specific allele mining as well as genome-wide association mapping.

Endoscopic management of duodenal adenomas in familial adenomatous polyposis--a single-center experience.

BACKGROUND: Duodenal lesions (DLS) are common in patients with familial adenomatosis polyposis (FAP), and screening for duodenal adenocarcinoma (DA) is currently recommended. Endoscopic treatment of DLS is controversial. AIM: To report management and outcomes of endoscopic therapy for DLS in patients with FAP. METHODS: The records of patients with FAP who underwent endoscopic surveillance or therapy for DLS over a 15-year period were reviewed. Endoscopic intervention included endoscopic surveillance with biopsies, argon plasma coagulation (APC), endoscopic mucosal resection (EMR), EMR with APC, and ampullectomy. Main outcome measurements were recurrence and histology of DLS after endoscopic therapy, complications of endoscopic therapy, and need for duodenectomy. RESULTS: Seventy-one patients with FAP and DLS were identified from our endoscopy database as undergoing upper endoscopy for screening and/or surveillance (1995-2009). Mean follow up was 4.5 years (1-15 years). Seventy of the seventy-one (98.5%) patients had multiple flat DLS. Most of the patients were followed with yearly biopsies. APC was performed in 17 patients and EMR was performed in eight patients; in five of the eight EMR patients, APC was also performed to treat the edges of EMR site. During the follow up, 17/55 (31%) patients had histological progression (HP). HP was seen in 5/16 (31%) patients who underwent APC (one was lost to follow-up) and 12/40 (30%) patients followed with biopsies alone. Recurrence of lesions was noted in all patients. Two patients underwent duodenectomy. None of the patients developed DA during follow up. CONCLUSIONS: Endoscopic surveillance with directed endotherapy for DLS in FAP is feasible and safe when diligently performed.

Tuberculosis of gallbladder with candidiasis, a rare entity.

Gallbladder tuberculosis (GT) is an extremely rare condition. This is thought to be due to the protective property of bile against the infection. Clinical and radiological diagnosis of GT is difficult. We describe a case of GT who initially presented to us with jaundice, a right hypochondrial mass and computed tomographic findings suggestive of gallbladder empyema. Diagnosis was made from histopathological examination of the resected gallbladder which revealed epitheloid granulomas with caseating necrosis and presence of Langhan's giant cells. From a literature search and to the best of our knowledge, this is the first GT to be reported in South East Asia.

Self-expanding metal stents for biliary drainage in patients with resectable pancreatic cancer: single-center experience with 79 cases.

BACKGROUND AND AIMS: To study pre-operative and peri-operative course and outcome on follow up after pancreaticoduodenenctomy (PD) for resectable pancreatic cancer amongst patients receiving self-expanding metal stents (SEMS). METHODS: Medical charts of consecutively reviewed patients (2005-2009) with resectable pancreatic cancer and SEMS placement before PD at the MD Anderson Cancer Center (MDACC) were studied. RESULTS: Seventy-nine patients (mean age, 68 ± 9 years; 54% males) undergoing PD after SEMS placement were analyzed. Of these, 70% (55/79) had come with previous plastic stents placed within a median of 29 (5-216) days because of presentation and most (95%) underwent neoadjuvant chemoradiation after SEMS placement. The median interval between SEMS placement and PD was 120 (range 28-306) days. There were no technical difficulties during PD. The resected tumor was stage T3 in 72 patients, positive node in 44, lymphovascular invasion in 47, and perineural invasion in 62. Within 30 days after surgery, 26 (33%) patients developed complications requiring intervention, but none died. During a median follow-up of 349 (14-1,508) days after surgery, 32 (41%) patients developed metastatic disease, and 20 (25%) died; median survival was approximately 3 years. Development of metastatic disease during follow-up independently predicted survival with hazard ratio of 16 (95% CI: 4-68; P = 0.0001). CONCLUSIONS: Contrary to the tendency of avoiding the use of metal stents for biliary decompression amongst patients with resectable pancreatic cancer, our study demonstrated that SEMS did not adversely affect surgical technique, postoperative course, or long-term outcome. Therefore, metal stents should be considered for patients with resectable pancreatic cancer who will undergo preoperative chemoradiation.

Optimum palliation of inoperable hilar cholangiocarcinoma: comparative assessment of the efficacy of plastic and self-expanding metal stents.

BACKGROUND: Endoscopic retrograde biliary drainage (ERBD) with plastic or self-expanding metal stents (SEMS) is often performed for palliative care for cholangiocarcinoma. OBJECTIVE: The objective was to compare the clinical effectiveness, including stent patency, complication rate, and need for salvage percutaneous transhepatic biliary drainage, of SEMS and plastic stents. METHODS: A total of 100 patients with inoperable cholangiocarcinoma were identified from an endoscopic database from 1/1/01 to 9/30/06 at a tertiary cancer hospital and their clinical history was retrospectively reviewed. All patients were followed to death, re-intervention, or for at least one year. Stent patency and patient survival were estimated by Kaplan-Meier analysis, supplemented by the log-rank test for comparisons between groups. RESULTS: Forty-eight patients had SEMS placed and 52 patients had plastic stents placed. ERBD was successful in 46 (95.8%) in the SEMS group and 49 (94.2%) in the plastic group (P = 0.67). Median patency times were 1.86 months in the plastic group and 5.56 months in the SEMS group (P < 0.0001). A mean of 1.53 and 4.60 re-interventions were performed in the SEMS and plastic groups, respectively (P < 0.05). Complications occurred in 4/48 (8.3%) in the SEMS group and 4/52 (7.7%) in the plastic group (P = 0.79). Median survival was 9.08 and 8.22 months in the SEMS and plastic stent groups, respectively (P = 0.50). CONCLUSION: Metallic stent patency was superior to that of plastic stents in all Bismuth-Corlette classifications of hilar cholangiocarcinoma with similar complication rates. SEMS seem to be cost-effective and, when feasible, should be considered as an initial intervention in patients with inoperable hilar cholangiocarcinoma.

Association of aldosterone synthase (CYP11B2 C-344T) gene polymorphism & susceptibility to essential hypertension in a south Indian Tamil population.

BACKGROUND & OBJECTIVE: Renin-angiotensin aldosterone system (RAAS) plays an important role in the regulation of blood pressure. Aldosterone, synthesized by aldosterone synthase in the adrenal cortex is encoded by the CYP11B2 gene. In this case-control study we examined the association between CYP11B2 C-344T polymorphism and essential hypertension in south Indian Tamil population. METHODS: The study was conducted in 406 hypertensive cases and 424 healthy controls from Tamil population. Genotyping was performed by PCR-restriction fragment length polymorphism method. Statistical analysis was performed by logistic regression analysis. RESULTS: The 344TT homozygous variant genotype (OR-1.8; 95% CI: 1.1-2.8; P=0.02) and T allele (P=0.007) were found to be significantly associated with hypertension. In gender based analysis, the risk was significantly higher in male hypertensives (OR-1.8; 95% CI: 1.0-3.6, P=0.05) but not in female subjects. INTERPRETATION & CONCLUSION: A significant association between CYP11B2 gene polymorphism and essential hypertension was observed and the risk was confined to male subjects in south Indian Tamil population.

Gly460Trp polymorphism of the ADD1 gene and essential hypertension in an Indian population: A meta-analysis on hypertension risk.

BACKGROUND: Essential hypertension is a complex genetic trait. Genetic variant of alpha adducin (ADD1) gene have been implicated as a risk factor for hypertension. Given its clinical significance, we investigated the association between ADD1 Gly460Trp gene polymorphism and essential hypertension in an Indian population. Further, a meta-analysis was carried out to estimate the risk of hypertension. METHODS: In the current study, 432 hypertensive cases and 461 healthy controls were genotyped for the Gly460Trp ADD1 gene polymorphism. Genotyping was determined by real time PCR using Taqman assay. Multiple logistic regression analysis was used to detect the association between Gly460Trp polymorphism and hypertension. RESULTS: No significant association was found in the genotype and allele distribution of Gly460Trp polymorphism with hypertension in our study. A total of 15 case-control studies were included in the meta-analysis. There was no evidence of the association of Gly460Trp polymorphism with hypertension in general or in any of the sub group. CONCLUSIONS: We found that the Gly460Trp polymorphism is not a risk factor for essential hypertension in a south Indian Tamilian population. However, the role of ADD1 polymorphism may not be excluded by a negative association study. Further, large and rigorous case-control studies that investigate gene-gene-environment interactions may generate more conclusive claims about the molecular genetics of hypertension.

Polymorphic variants of beta1 adrenergic receptor gene (Ser49Gly & Arg389Gly) in healthy Tamilian volunteers.

BACKGROUND & OBJECTIVES: Several studies reported the polymorphisms of beta1-adrenergic receptor gene in healthy volunteers and its influence on cardiovascular disorders. We investigated the genotype and allele frequencies of Ser49Gly and Arg389Gly polymorphism in healthy volunteers of South Indian Tamilian population vis-à-vis other major ethnic groups. METHODS: The genetic variants were determined by using Taqman 5' nuclease assay- real time PCR analysis in 533 normal healthy volunteers (18-60 yr; M=290; F=243). The allelic discrimination analysis was done by 7700 SDS software. RESULTS: The estimated genotype and allele frequencies of Ser49Gly and Arg389Gly polymorphism were compared with other major populations. The frequencies of the variant alleles Gly49 and Gly389 were 15.1 and 25.8 per cent respectively. INTERPRETATION & CONCLUSIONS: Our study shows that interethnic variation exists in the polymorphisms of beta1-adrenergic receptor gene and the results generated in this study might serve as a genetic marker for further studies in Tamilian (South India) population.

Genetic variants of beta(1)-adrenoceptor gene polymorphisms (Ser49Gly and Arg389Gly) and essential hypertension in a south Indian Tamil population.

1. Essential hypertension is a complex polygenic disorder, the pathogenesis of which is dependent on an interplay between genetic and environmental factors. Various studies suggest an association between beta(1)-adrenoceptor gene polymorphisms (Ser49Gly and Arg389Gly) and cardiovascular disorders, including hypertension, cardiomyopathy and congestive heart failure. 2. The genetic profile of the beta(1)-adrenoceptor gene has not yet been documented for any Indian population. Thus, the aim of the present study was to investigate the association between beta(1)-adrenoceptor gene polymorphisms and essential hypertension in a south Indian Tamil population. 3. The present case-control study included 438 patients with essential hypertensives and 444 healthy volunteers from the Tamil population. Genotyping was performed using real-time polymerase chain reaction. 4. Genotype and allele frequencies of Ser49Gly and Arg389Gly polymorphism were compared between hypertensive patients and healthy volunteers. The homozygous variant genotype Gly49Gly of the Ser49Gly polymorphism was higher in hypertensive patients compared with controls (12.3 vs 7.4%, respectively). After adjusting for confounding variables (odds ratio (OR) 2.0; 95% confidence interval (CI) 1.2-2.9; P < 0.01) by multilogistic regression analysis, the gene was found to be associated with hypertension. A significant interaction was observed in hypertensive patients carrying the Ser49Gly/Gly49Gly x Arg389Gly/Gly389Gly genotypes (OR 1.9; 95% CI 1.1 2.7). 5. In conclusion, the Ser49Gly polymorphism is associated with essential hypertension in a south Indian Tamil population. The results of the present study deviate from those of previous studies, implying that marked interethnic difference exist in beta(1)-adrenoceptor gene polymorphisms.

Exploiting rice-sorghum synteny for targeted development of EST-SSRs to enrich the sorghum genetic linkage map.

The sequencing and detailed comparative functional analysis of genomes of a number of select botanical models open new doors into comparative genomics among the angiosperms, with potential benefits for improvement of many orphan crops that feed large populations. In this study, a set of simple sequence repeat (SSR) markers was developed by mining the expressed sequence tag (EST) database of sorghum. Among the SSR-containing sequences, only those sharing considerable homology with rice genomic sequences across the lengths of the 12 rice chromosomes were selected. Thus, 600 SSR-containing sorghum EST sequences (50 homologous sequences on each of the 12 rice chromosomes) were selected, with the intention of providing coverage for corresponding homologous regions of the sorghum genome. Primer pairs were designed and polymorphism detection ability was assessed using parental pairs of two existing sorghum mapping populations. About 28% of these new markers detected polymorphism in this 4-entry panel. A subset of 55 polymorphic EST-derived SSR markers were mapped onto the existing skeleton map of a recombinant inbred population derived from cross N13 x E 36-1, which is segregating for Striga resistance and the stay-green component of terminal drought tolerance. These new EST-derived SSR markers mapped across all 10 sorghum linkage groups, mostly to regions expected based on prior knowledge of rice-sorghum synteny. The ESTs from which these markers were derived were then mapped in silico onto the aligned sorghum genome sequence, and 88% of the best hits corresponded to linkage-based positions. This study demonstrates the utility of comparative genomic information in targeted development of markers to fill gaps in linkage maps of related crop species for which sufficient genomic tools are not available.

Synchronous adenocarcinoma of caecum, transverse colon and jejunum.

Synchronous cancers are defined as malignant tumours that occur simultaneously, each of which must be distinct with no possibility of one being the metastasis of the other. A 65 year old gentleman presented to us with two month history of epigastric pain associated with anaemia, loss of appetite and weight. He has no history of malignancy in his family. Colonoscopy revealed tumours at transverse colon and caecum. Intra-operatively, tumours were sited at caecum, transverse colon and jejunum. Tumours were diagnosed as synchronous adenocarcinoma histopathologically with loss of expression of MLH1 and MSH2. From literature search, this is the first reported triple synchronous tumours of the caecum, transverse colon and jejunum. We believe that this gentleman developed triple synchronous tumour through the sporadic MSI pathway.