Mixotrophic metabolism in Burkholderia kururiensis subsp. thiooxydans subsp. nov., a facultative chemolithoautotrophic thiosulfate oxidizing bacterium isolated from rhizosphere soil and proposal for classification of the type strain of Burkholderia kururiensis as Burkholderia kururiensis subsp. kururiensis subsp. nov.

A thiosulfate-oxidizing facultative chemolithoautotrophic Burkholderia sp. strain ATSB13^T was previously isolated from rhizosphere soil of tobacco plant. Strain ATSB13^T was aerobic, Gram-staining-negative, rod shaped and motile by means of sub-terminal flagellum. Strain ATSB13^T exhibited mixotrophic growth in a medium containing thiosulfate plus acetate. A phylogenetic study based on 16S rRNA gene sequence analysis indicated that strain ATSB13^T was most closely related to Burkholderia kururiensis KP23^T (98.7%), Burkholderia tuberum STM678^T (96.5%) and Burkholderia phymatum STM815^T (96.4%). Chemotaxonomic data [G+C 64.0 mol%, major fatty acids, C_18:1 ω7c (28.22%), C_16:1 ω7c/15 iso 2OH (15.15%), and C_16:0 (14.91%) and Q-8 as predominant respiratory ubiquinone] supported the affiliation of the strain ATSB13^T within the genus Burkholderia. Though the strain ATSB13^T shared high 16S rRNA gene sequence similarity with the type strain of B. kururiensis but considerably distant from the latter in terms of several phenotypic and chemotaxonomic characteristics. DNA–DNA hybridization between strain ATSB13^T and B. kururiensis KP23^T was 100%, and hence, it is inferred that strain ATSB13^T is a member of B. kururiensis. On the basis of data obtained from this study, we propose that B. kururiensis be subdivided into B. kururiensis subsp. kururiensis subsp. nov. (type strain KP23^T = JCM 10599^T = DSM 13646^T) and B. kururiensis subsp. thiooxydans subsp. nov. (type strain ATSB13^T = KACC 12758^T).     

Effect of hydrotropes on solubility and mass transfer coefficient of amyl acetate

This paper presents a comprehensive study on the effect of citric acid, sodium benzoate, sodium salicylate and urea (hydrotropes) on the solubility and mass transfer coefficient for the extraction of amyl acetate in water. The influence of a wide range of hydrotrope concentration (0–3.0?mol/l) and different temperatures (303–333?K) on the solubility of amyl acetate has been studied. The influence of different hydrotrope concentrations on the mass transfer coefficients for amyl acetate–water system has been ascertained. Setschenow constant, K_s, a measure of the effectiveness of hydrotrope has been determined for each case. The solubility of amyl acetate increases with increase in hydrotrope concentration and also with system temperature. Consequent to the increase in the solubility of amyl acetate, the mass transfer coefficient was also found to increase with increase in hydrotrope concentration. A Minimum Hydrotropic Concentration (MHC) was found essential to show a significant increase in the solubility and mass transfer coefficient for amyl acetate–water system. The enhancement factor, which is the ratio of value in presence and absence of a hydrotrope is reported for both solubility and mass transfer coefficients.     

Bacteriophage Mu: a transposing replicon

Mu DNA replication has been carried out in vitro on cellophane discs in the presence of dBUTP. If the DNA is sheared to 80 kb pieces, the Mu replicas band anomalously in CsCl gradients between hybrid and light DNA density positions. The intermediate density DNA comprises semiconservatively replicated Mu sequences, flanked by unreplicated light DNA. This and previous data are consistent with replication occurring within Mu boundaries. Both the synthesis of Mu sequences and the intermediate density DNA are abolished by protein synthesis inhibition in vivo just prior to lysis on cellophane discs. These observations indicate that at least some steps in bona fide Mu transposition-replication are being observed in vitro.     

Operative vaginal delivery and neonatal and infant adverse outcomes: population based retrospective analysis

Objective To compare the risk of neonatal and infant adverse outcomes between vacuum and forceps assisted deliveries.Design Population based study.Setting US linked natality and mortality birth cohort file and the New Jersey linked natality, mortality, and hospital discharge summary birth cohort file.Participants Singleton live births in the United States (n = 11 639 388) and New Jersey (n = 375 351).Main outcome measures Neonatal morbidity and mortality.Results Neonatal mortality was comparable between vacuum and forceps deliveries in US births (odds ratio 0.94, 95% confidence interval 0.79 to 1.12). Vacuum delivery was associated with a lower risk of birth injuries (0.69, 0.66 to 0.72), neonatal seizures (0.78, 0.68 to 0.90), and need for assisted ventilation (< 30 minutes 0.94, 0.92 to 0.97; ≥ 30 minutes 0.92, 0.88 to 0.98). Among births in New Jersey, vacuum extraction was more likely than forceps to be complicated by postpartum haemorrhage (1.22, 1.07 to 1.39) and shoulder dystocia (2.00, 1.62 to 2.48). The risks of intracranial haemorrhage, difficulty with feeding, and retinal haemorrhage were comparable between both modes of delivery. The sequential use of vacuum and forceps was associated with an increased risk of need for mechanical ventilation in the infant and third and fourth degree perineal tears.Conclusion Although vacuum extraction does have risks, it remains a safe alternative to forceps delivery.     

Ecological risk assessment of accidental release of flowback water: A conceptual framework

The aim of the study is to conduct an ecological risk assessment of accidental release of flowback water into freshwater body. Flowback water produced from the hydraulic fracturing process has a complex combination of high concentration of salts, organic compounds and metals. The toxicity of flowback water is assessed and an exposure assessment method for the inorganic constituents of the flowback water is developed. An equation for risk is derived to characterize the risk of the flowback water to the aquatic ecology. A case study is conducted for accidental release of hydraulic fracturing flowback water in Montney unconventional play trend in northern British Columbia. The flowback water quality data for 212 wells, including the concentrations of various salt ions, metal ions, and hydrogen sulfide, is collected for the assessment. The risk quotient is found to be 0.16 (<1), proving no significant risk to the aquatic ecosystem with 90% confidence. However, the overall results of the uncertainty and scenario analysis concludes that the risk to the ecology cannot be completely overlooked. Scenario analysis was done for monthly creek discharge and a relationship between risk quotient and the ratio of spill volume to the creek discharge was derived.