Cr(VI) and azo dye removal using a hollow-fibre membrane system functionalized with a biogenic Pd-magnetite catalyst.

This study investigates the application of a hybrid system combining hollow-fibre membrane technology with the reductive abilities of magnetic nanoparticles for the remediation of toxic Cr(VI) and the azo dye, Remazol Black B. Nano-scale biogenic magnetite (Fe3O4), formed by microbial reduction of the mineral ferrihydrite, has a high reductive capacity due to the presence of Fe(II) in the mineral structure. The magnetic nanoparticles (approximately 20 nm) can be arrayed with Pd0 nanoparticles (approximately 5 nm) making a catalytically active nanomaterial. Membrane units, with and without nanoparticles, were challenged with either Cr(VI) or azo dye and some were supplemented with sodium formate, as an electron donor for contaminant reduction promoted by the Pd. The combination of Pd-magnetite with formate resulted in the most effective remediation strategy for both contaminants and the lifetime of the membrane unit was also increased, with 55% (19 days) and 70% (23 days) removal of the azo dye and Cr(VI), respectively. Low flow rates of 0.1 ml/min resulted in improved efficiencies due to increased contact time with the membrane/nanoparticle unit, with 70-75% removal of each contaminant. Chemical analyses of the nanoparticles post-exposure to Cr(VI) in the membrane modules indicated Pd to be more oxidized when Cr removal was maximized, and that the Cr was partially reduced to Cr(III) at the surface of the magnetite. These results have demonstrated that hollow-fibre membrane units can be enhanced for the removal of soluble, redox sensitive contaminants by incorporation of a layer of palladized biogenic nanoparticulate magnetite.

Recurrent implantation failure: definition and management.

Recurrent implantation failure refers to failure to achieve a clinical pregnancy after transfer of at least four good-quality embryos in a minimum of three fresh or frozen cycles in a woman under the age of 40 years. The failure to implant may be a consequence of embryo or uterine factors. Thorough investigations should be carried out to ascertain whether there is any underlying cause of the condition. Ovarian function should be assessed by measurement of antral follicle count, FSH and anti-Mu¨llerian hormone. Increased sperm DNA fragmentation may be a contributory cause. Various uterine pathology including fibroids, endometrial polyps, congenital anomalies and intrauterine adhesions should be excluded by ultrasonography and hysteroscopy. Hydrosalpinges are a recognized cause of implantation failure and should be excluded by hysterosalpingogram; if necessary, laparoscopy should be performed to confirm or refute the diagnosis. Treatment offered should be evidence based, aimed at improving embryo quality or endometrial receptivity. Gamete donation or surrogacy may be necessary if there is no realistic chance of success with further IVF attempts.

Biomineralization: linking the fossil record to the production of high value functional materials.

The microbial cell offers a highly efficient template for the formation of nanoparticles with interesting properties including high catalytic, magnetic and light-emitting activities. Thus biomineralization products are not only important in global biogeochemical cycles, but they also have considerable commercial potential, offering new methods for material synthesis that eliminate toxic organic solvents and minimize expensive high-temperature and pressure processing steps. In this review we describe a range of bacterial processes that can be harnessed to make precious metal catalysts from waste streams, ferrite spinels for biomedicine and catalysis, metal phosphates for environmental remediation and biomedical applications, and biogenic selenides for a range of optical devices. Recent molecular-scale studies have shown that the structure and properties of bionanominerals can be fine-tuned by subtle manipulations to the starting materials and to the genetic makeup of the cell. This review is dedicated to the late Terry Beveridge who contributed much to the field of biomineralization, and provided early models to rationalize the mechanisms of biomineral synthesis, including those of geological and commercial potential.

Effect of increased body mass index on oocyte and embryo quality in IVF patients.

Obesity may have an adverse effect on the outcome of IVF/intracytoplasmic sperm injection (ICSI) treatment. In this study, the effects of increased body mass index (BMI) on oocyte and embryo quality during IVF cycles were studied. A retrospective analysis of 426 IVF/ICSI cycles was performed. Cycles were classified according to the BMI: normal BMI (19-24.9 kg/m(2)), overweight (25-29.9 kg/m(2)) and obese (> or = 30 kg/m(2)). Cycles were further stratified based on age (group 1, < 35 years; group 2, > or = 35 years). Markers of oocyte quality (number of oocytes inseminated and fertilization rate) and embryo quality (utilization rate, number of embryos discarded and cryopreserved, and mean embryo grade) were examined. In group 1, obesity had a significant adverse effect on the mean embryo grade (P = 0.02), the embryo utilization rate (P = 0.01), number of embryos discarded (P = 0.007) and cryopreserved (P < 0.05). In group 2, there was no difference in markers of embryo quality between the three BMI ranks. Obesity did not have any significant effect on markers of oocyte quality or clinical pregnancy rates. In conclusion, obesity may adversely affect embryo quality in young women (<35 years) undergoing IVF/ICSI, while the oocyte quality is not affected.

Interruption of parturition in rats by morphine: a result of inhibition of oxytocin secretion.

Oxytocin secretion is inhibited by opioids, and oxytocin is important in parturition. The effects on parturition of morphine, a relatively selective mu-opioid receptor agonist, were studied in the rat. Morphine or vehicle with or without the opiate antagonist naloxone were administered immediately after the birth of the second pup and the subsequent course of parturition was recorded in a total of 80 rats. Both s.c. morphine (10 mg/kg) and intracerebroventricular (i.c.v.) morphine (18 micrograms through a previously implanted cannula) interrupted parturition, delaying the birth of the sixth pup after treatment to 187.3 +/- 35.9 (S.E.M.) min and 195.4 +/- 19.5 min respectively, compared with 46.4 +/- 3.7 and 66.1 +/- 17.5 min after vehicle alone. The dose of morphine given i.c.v. had no effect when given s.c. Naloxone given concurrently prevented the effects of morphine. Eventually the rate of parturition in the morphine-treated groups recovered. Perinatal pup mortality rate was not increased when morphine was given to the mothers, but it did inhibit the expression of normal intrapartum maternal behaviour. Pup mortality was increased 48 h post partum by morphine given during parturition, and it reduced the proportion of rats with normal maternal behaviour 24 h post partum. Morphine did not affect spontaneous or oxytocin-stimulated contractile activity of the parturient uterus in vitro. The concentration of oxytocin in trunk blood plasma was decreased 40 min after i.c.v. morphine (24.3 +/- 3.9 vs 39.3 +/- 6.5 pmol/l in controls), as was vasopressin (7.2 +/- 1.5 vs 19.7 +/- 4.5 pmol/l in controls). Intravenous infusion of oxytocin (2-5 mU/min for 144.3 +/- 8.2 min; total infused 448.5 +/- 61.9 mU) after i.c.v. morphine re-started parturition; all pups were born to these rats (mean time to pup 6, 110.3 +/- 12.7 min) before the i.v. vehicle-infused rats given i.c.v. morphine re-started (mean time to pup 6, 406.3 +/- 125.2 min). It is concluded that morphine given during parturition acts centrally through opioid receptors to inhibit oxytocin secretion, and impairs the expression of maternal behaviour. Reversal of the effects of morphine on parturition by i.v. oxytocin demonstrates the important role of oxytocin in fetus ejection and expulsion.

Clinical experience with the single-plate Molteno implant in complicated glaucomas.

Ninety patients with medically uncontrollable glaucomas and poor surgical prognoses received single-plate Molteno implants (Optomat Supplies, Dunedin, New Zealand) without postoperative adjunctive systemic antifibrosis therapy. Eleven patients had insufficient follow-up for assessment of intraocular pressure (IOP) or visual acuity outcome. The initial Molteno implant procedures in the remaining 79 patients were successful (IOP less than or equal to 21 mmHg with at least 6 months' follow-up) in 26 (63%) of the 41 patients older than 12 years of age with non-neovascular glaucomas in aphakia/pseudophakia; 7 (70%) of the 10 patients older than 12 years of age with non-neovascular glaucomas in phakic eyes after failed filtering surgery; 7 (47%) of the 15 patients with neovascular glaucomas; and 7 (54%) of the 13 patients younger than 13 years of age with non-neovascular glaucomas. The visual acuities remained within one line of their preoperative levels or improved in 31 (76%) of the 41 aphakic or pseudophakic eyes with non-neovascular glaucomas; 3 (30%) of the 10 phakic eyes with non-neovascular glaucomas after failed filtering surgery; 10 (67%) of the 15 eyes with neovascular glaucomas; and 9 (100%) of the 9 eyes with non-neovascular glaucomas in patients younger than 13 years of age on whom Snellen acuity was available.(ABSTRACT TRUNCATED AT 250 WORDS)

Mycoplasma pneumonia: a study on hospitalized American patients with pneumonia in Vietnam.

A prospective study on consecutively hospitalized pneumonia patients showed that 41.5% of 58 patients had a fourfold rise in the complement-fixation titer for Mycoplasma pneumoniae. Viral isolation techniques and serologic tests for influenza A1, A2 and B, parainfluenza 1 and 3, respiratory syncytial virus and the adeno virus group yielded only a single positive isolate for influenza A2. Serologic tests for melioidosis, leptospirosis, scrub, murine and epidemic typhus and psittacosis were all negative. The clinical manifestations were not distinctive for the positive M. pneumoniae patients when compared with the patients having a negative M. pneumoniae complement-fixation test. The symptoms and signs and laboratory and radiologic findings were similar to those described in other reports on primary atypical pneumonia.

Furnace temperature profiles: measurement by spectroscopic methods.

The determination of atmospheric temperature profiles from ir radiance data transmitted by satellites is fast becoming a reliable meteorological tool. However, high temperature applications of the technique have hitherto been restricted, the main difficulty being poor convergence beyond temperature peaks. This paper shows that by modifying an existing atmospheric iterative inversion technique to combine radiance measurements from two detectors at each end of a common line of sight through the hot gas, retrieval of the temperature profile is possible over the whole gas slab. Practical applications include research into burner and rocket design and tighter control of industrial furnace operation.