Biochemical, functional and molecular characterization of pigeon pea rhizobia isolated from semi-arid regions of India.

Pigeon pea (Cajanus cajan (L.) Millspaugh) is among the top ten legumes grown globally not only having high tolerance to environmental stresses along, but also has the high biomass and productivity with optimal nutritional profiles. In the present study, 55 isolates of rhizobia were identified from 22 nodule samples of pigeon pea collected from semi-arid regions of India on the basis of morphological, biochemical, plant growth promoting activities and their ability to tolerate the stress conditions viz. pH, salt, temperature and drought stress. Amongst all the 55 isolates, 37 isolates showed effective nodulation under in vitro conditions in pigeon pea. Further, five isolates having multiple PGP activities and high in vitro symbiotic efficiency were subjected to 16S rRNA sequencing and confirmed their identities as Rhizobium, Mesorhizobium, Sinorhizobium sp. Further these 37 isolates were characterized at molecular level using ARDRA and revealed significant molecular diversity. Based on UPGMA clustering analysis, these isolates showed significant molecular diversity. The high degree of molecular diversity is due to mixed cropping of legumes in the region. The assessment of genetic diversity and molecular characterization of novel strains is a very important tool for the replacement of ineffective rhizobial strains with the efficient strains for the improvement in the nodulation and pigeon pea quality. The pigeon pea isolates with multiple PGPR activities could be further used for commercial production.

Molecular Diversity Analysis of Plant Growth Promoting Rhizobium Isolated from Groundnut and Evaluation of Their Field Efficacy.

Rhizobium are nitrogen-fixing bacteria which possess the nif gene that codes for the nitrogenase enzyme involved in the reduction of atmospheric dinitrogen (N2) to ammonia. Thirty rhizobial strains were identified from ten groundnut plant root nodules collected from semi-arid regions of Rajasthan, India. The isolates were initially identified on the basis of morphological, biochemical, and molecular characteristics. These rhizobium strains were further screened for plant growth promoting activities. Twenty-eight strains were able to produce indole acetic acid, nine strains could solubilize phosphate, and twenty-nine strains exhibited positive results for siderophore and ammonia production. All the bacterial strains were able to efficiently nodulate the groundnut under pot conditions and based on multiple PGP activities six strains were selected for field evaluation. Field experiments confirmed the effectiveness of these selected rhizobium strains resulted in significantly higher nodule number, nodule dry weight, grain yield, and yield components of inoculated plants. Inoculation of the rhizobium strain GN223 followed by GN221 resulted in high yield and field efficiency. Isolation of effective microbial strains is the prerequisite to increase the yield which is evident from the field data of the present study. Hence, these strains might serve as proficient inoculants.

Improvement in ion confinement time with multigrid configuration in an inertial electrostatic confinement fusion device.

Improvement in the functionality of an inertial electrostatic confinement fusion (IECF) device has been investigated through kinetic simulation. Previously, we achieved a neutron generation rate of 10^{6} neutrons per second, but higher rates and better plasma confinement are necessary for broader applications. We compared a traditional single-grid IECF device with a triple-grid variant to evaluate the benefits of using multiple grids for ion confinement. Our computational models, using the 2D-3V xoopic code, suggest that the triple-grid device, with its optimized potentials, could significantly enhance ion confinement. The models show that the triple-grid design directs ion beams more effectively to the center, in contrast with the more scattered ion distribution in the single-grid design. This results in longer ion lifetimes in the triple-grid system due to its modified electrostatic fields. In the standard single-grid IECF device, the primary reasons for ion loss are chaotic ion trajectories and interactions with residual gases. By operating the triple-grid device under very low background gas pressure and with a focused field structure, we expect to achieve improved ion confinement.

Kinetic characteristics of ions in an inertial electrostatic confinement device.

The kinetic analyses are quite important when it comes to understanding the particle behavior in any device as they start to deviate from a continuum nature. In the present study, kinetic simulations are performed using the particle-in-cell method to analyze the behavior of ions inside a cylindrical inertial electrostatic confinement fusion (IECF) device which is being developed as a tabletop neutron source. Here, the lighter ions, like deuterium, are accelerated by applying an electrostatic field between the chamber wall (anode) and the cathode (cylindrical gridded wire), placed at the center of the device. The plasma potential profiles obtained from the simulated results indicate the formation of multiple potential well structures inside the cathode grid depending upon the applied cathode potential (from -1 to -5 kV). The ion density at the core region of the device is found to be of the order of 10^{16}m^{-3}, which closely resembles the experimental observations. Spatial variation of ion energy distribution function has been measured in order to observe the characteristics of ions at different cathode voltages. Finally, the simulated results are compared and found to be in good agreement with the experimental profiles. The present analysis can serve as a reference guide to optimize the technological parameters of the discharge process in IECF devices.

Dynamics of changes in methanogenesis and associated microflora in a flooded alluvial soil following repeated application of dicyandiamide, a nitrification inhibitor.

Influence of repeated application of the nitrification inhibitor dicyandiamide (DCD), on CH(4) production and associated microflora in a flooded alluvial soil, was investigated in a laboratory incubation study. Application of DCD at the time of soil incubation resulted in a substantial reduction in CH(4) production (31% over that of untreated control). Second repeat application of DCD, on the contrary, annulled the inhibitory effect on CH(4) production, restoring it to the level of unamended soil. Application of the third dose of DCD maintained CH(4) production almost to the same extent as that of second application. The alleviation of the initial inhibitory effect of DCD on CH(4) production was linked to the enhanced degradation of DCD following its repeated application to the flooded soil. Admittedly, abatement of the initial inhibitory effect of DCD on CH(4) production in soil repeatedly amended with DCD was also related to the inhibition of CH(4)-oxidizing bacterial population and noticeable stimulation of heterotrophic bacterial population. Results suggest that repeat application of DCD with fertilizer-N to flooded rice soils might not be effective in controlling CH(4) production under field condition.

Right pulmonary artery left atrium communication.

A 12-year-old boy presented with central cyanosis, clubbing, and ejection systolic murmur in the left second and third intercostal space. Chest roentgenogram showed a round opacity on the right border of cardiac silhouette. Echocardiography revealed a communication between right pulmonary artery and left atrium, which was later confirmed on selective pulmonary cineangiography. Successful surgical ligation without cardiopulmonary bypass resulted in the cure of the disease.

A new repair for anomalous left coronary artery.

We report a new technique of left coronary artery implantation to the aorta with interposition of a tube created from the great arterial wall for anomalous left coronary artery from pulmonary artery. This technique was used in 3 patients, of which 2 patients survived. It achieves two coronary artery repair and avoids problems related to extensive mobilization of coronary artery for translocation. It is easily reproducible.

Univentricular repair: is routine fenestration justified?

BACKGROUND: A decade after the introduction of baffle fenestration, the outcome of Fontan-type repair for hearts with a functional single ventricle finally looks promising. Our study was designed to assess the impact of fenestration on the outcome of univentricular repairs. METHODS: From January 1988 to December 1997, 348 patients (104 with tricuspid atresia and 244 with other morphological diagnoses) underwent univentricular repair at our institute. Since 1994, routine fenestration of the atrial baffle was performed in all patients (n = 126). RESULTS: The overall Fontan failure rate was 14% (50 of 348) and included 45 early deaths and five Fontan take downs. Absence of fenestration was the only and highly significant predictor of Fontan failure (risk ratio [RR] 3.3, 95% confidence interval [CI] 1.49 to 7.31, p = 0.002). Significant pleural effusion was seen in 27% of patients. Absence of fenestration of the atrial baffle (RR 3.97, 95% CI 2.17 to 7.26, p < 0.001) and aortic cross-clamp time more than 60 minutes (RR 2.15, 95% CI 1.3 to 3.5, p = 0.002) were found to be significant risk factors. The follow-up ranged from 6 to 120 months (mean 46.0 +/- 18.0 months). There were 12 late deaths and 5 patients were lost to follow-up. Actuarial survival (Kaplan Meier) at 90 months was 81% +/- 4%. Two hundred and fifty-eight patients (90%) were in New York Heart Association class I at their last follow-up visit. Oxygen saturation in the fenestrated group ranged from 85% to 94% (mean 89%). Thirty patients (26%) had spontaneous closure of the fenestration over a mean period of 34 months, and there has been no incidence of late systemic thromboembolism. In no instance has there been a need to close the fenestration. CONCLUSIONS: Elective fenestration of the intraatrial baffle is associated with decreased Fontan failure rate and decreased occurrence of significant postoperative pleural effusions. Routine elective fenestration of the atrial baffle may, therefore, be justified in all univentricular repairs.

Isolated congenital anterior mitral leaflet cleft: a rare cause of mitral insufficiency.

BACKGROUND AND AIM OF THE STUDY: Isolated cleft of the anterior mitral leaflet is a rare cause of mitral insufficiency. Although an established entity, due to its rarity the exact anatomic diagnosis is difficult to establish unless sought specifically. METHODS: Four patients (age range: 16 to 26 years) with isolated cleft of the anterior mitral leaflet were treated at the authors' institute. Clinical symptoms were typical of mitral insufficiency; the exact anatomic diagnosis was not established preoperatively in any patient. The cleft was directly sutured in all four patients and additional annuloplasty was performed in three. RESULTS: Postoperative echocardiography confirmed satisfactory results. After a mean follow up of 46.7 months (range: 3 to 84 months), one patient had mild mitral insufficiency and the remaining patients had no mitral regurgitation. CONCLUSION: In severe mitral insufficiency with no obvious mitral valve pathology and an intact atrial septum, a cleft of the anterior mitral leaflet should be sought. Repair of the cleft can restore normal mitral valve function.

Influence of salinity on methanogenesis and associated microflora in tropical rice soils.

In a laboratory incubation study, methane (CH4) production in two saline soils and a nonsaline soil sample was investigated under flooded conditions. Mean CH4 production was remarkable (630.86 ng CH4/g) in nonsaline alluvial soil, but low (12.97 ng CH4/g) in acid sulfate saline (Pokkali) soil which was attributed to the high sulfate content of the later. CH4 production was also low in the coastal saline (Canning) soil (142.36 ng CH4/g) but increased upon leaching the soil of its salt content. Addition of salts to the nonsaline alluvial soil at 4, 8, 16 and 20 dS/m progressively decreased CH4 production. The inhibition of CH4 production was related to low microbial activities as reflected by decreased microbial biomass C and low soil microbial population including that of methanogens.

Butachlor inhibits production and oxidation of methane in tropical rice soils under flooded condition.

In laboratory incubation experiments, application of a commercial formulation of the herbicide butachlor (N-butoxymethyl-2-chloro-2',6'-diethyl acetanilide) to three tropical rice soils, widely differing in their physicochemical characteristics, under flooded condition inhibited methane (CH4) production. The inhibitory effect was concentration dependent and most remarkable in the alluvial soil. Thus, following application of butachlor at 5, 10, 50 and 100 microg g(-1) soil, respectively, cumulative CH4 production in the alluvial soil was inhibited by 15%, 31%, 91% and 98% over unamended control. Since CH4 production was less pronounced in the sandy loam and acid sulfate soil, the impact of amendment with butchalor, albeit inhibitory, was less extensive than the alluvial soil. Inhibition of CH4 production in butachlor-amended alluvial soil was related to the prevention in the drop in redox potential as well as low methanogenic bacterial population especially at high concentrations of butachlor. CH4 oxidation was also inhibited in butachlor-amended alluvial soil with the inhibitory effect being more prevalent under flooded condition. Inhibition in CH4 oxidation was related to a reduction in the population of soluble methane monooxygenase producing methanotrophs. Results demonstrate that butachlor, a commonly used herbicide in rice cultivation, even at very low concentrations can affect CH4 production and its oxidation, thereby influencing the biogeochemical cycle of CH4 in flooded rice soils.

Adult cyanotic congenital heart disease: surgical experience.

Cyanotic congenital heart diseases constitute about 10 percent of total congenital heart disease cases in adults in the developing world. Prolonged cyanosis and old age adversely affect the outcome of surgery, thus posing a challenge to the cardiac surgeons. This study was conducted to assess the feasibility, safety and outcome of surgery in this group of patients. From January 1991 to December 1997, a total of 303 patients, aged 14 to 54 years (mean 19.8 +/- 1.5 years) with diagnosis of various cyanotic congenital heart diseases were operated at our institute. There were 210 males (69.3%). Two hundred and forty-seven patients (81.5%) had tetralogy of Fallot's physiology, 51 patients (16.8%) had single ventricle physiology and five (1.6%) had other lesions. Sixty-six patients (21.7%) had pre-operative complications such as haemoptysis, epistaxis, cerebrovascular accidents, brain abscess and infective endocarditis. Sixty patients (19.8%) had previous palliative shunts and 26 patients (8.5%) had coil embolisation of major aortopulmonary collaterals prior to surgery; 229 patients (75.5%) underwent biventricular repair, 52 (17.1%) had univentricular repair, 22 (7.7%) had palliative shunts and one patient had open ligation of a major aortopulmonary collateral in addition. In-hospital mortality was 3.3 percent. Follow-up period ranged from five months to seven years (mean 4.2 +/- 1.8 years). There were two late deaths. Of the 291 survivors, 11 were lost to follow-up. Two hundred and fifty-eight patients (92.1%) are in New York Heart Association class I. Significant residual defects warranting reoperation were present in four patients (1.3%). It is concluded that congenital heart surgery in older cyanotic patients can be performed safely with satisfactory results.

Potentially curative treatment in patients with hepatocellular cancer--results from the liver cancer research network.

BACKGROUND: The extent to which potentially curative therapies are used in patients with hepatocellular cancer (HCC) and their related outcomes are unknown in the US. AIM: To determine the rate and outcomes of potentially curative treatment in patients with HCC. METHODS: Eleven US centers followed patients with HCC between 2001 and 2007. We determined rates of liver transplantation, surgical resection, or tumour ablation during follow-up, examined differences in adjusted survival of patients receiving these treatments, and determined the factors associated with receipt of potentially curative treatment. RESULTS: Of the 267 patients, 76 (28%) patients had early HCC, defined as Child A or B cirrhosis, with a solitary HCC or ≤ 3 nodules, each ≤ 3 cm. Of these, 53 (69.7%) received curative treatment. Thirty six percent of patients with non-early HCC received curative treatment. Compared to patients with non-early HCC who did not receive curative treatment, patients with early HCC and curative treatment had the best survival [hazard ratio, HR = 0.19 (95% CI, 0.08-0.42)] followed by patients with advanced HCC who received curative treatment [HR = 0.37 (95% CI, 0.22-0.64)]. Baseline performance status was significantly associated with receipt of curative treatment as well as survival after adjusting for demographics, clinical characteristics, and HCC stage. CONCLUSIONS: In this multicenter database, most of the patients with early HCC received potentially curative treatment. However, only 28% of patients had early HCC. One-third of patients with non-early HCC also underwent curative therapy. Potentially curative treatment improved survival and this effect was seen in patients with early as well as non-early HCC.

Influence of heavy metals on methane oxidation in tropical rice soils.

In a laboratory incubation study, the effect of select heavy metals on methane (CH4) oxidation in two rice soils was investigated under two moisture regimes. Heavy metals differed in their effect on CH4 oxidation in both soils under the two water regimes. Cr significantly inhibited CH4 oxidation in the alluvial soil at 60% moisture holding capacity, while Cu stimulated the process. On the contrary, Zn inhibited CH4 oxidation in both alluvial and laterite soils only under flooded conditions. Application of rice straw alleviated the inhibitory effect of heavy metals on CH4 oxidation and CO2 production. Inhibition of CH4 oxidation in the alluvial soil was related to the methanotrophic bacterial population in Cr- and Zn-amended alluvial soil.