Dye adsorption onto mesoporous materials: pH influence, kinetics and equilibrium in buffered and saline media.

Mesoporous materials were used as adsorbents for dye removal in different media: non-ionic, buffered and saline. The mesoporous materials used were commercial (silica gel) as well as as-synthesised materials (SBA-15 and a novel mesoporous carbon). Dye adsorption onto all the materials was very fast and the equilibrium was reached before 1 h. The pH has a significant influence on the adsorption capacity for the siliceous materials since the electrostatic interactions are the driving forces. However, the influence of the pH on the adsorption capacity of the carbonaceous material was lower, since the van der Waals interactions are the driving forces. The ionic strength has a great impact on the siliceous materials adsorption capacity, being their adsorption capacity in a buffered medium six times higher than the corresponding to a non-ionic medium. Nevertheless, ionic strength does not influence on the dye adsorption on the mesoporous carbon. Overall, the as-synthesised carbon material presents a clear potential to treat dye effluents, showing high adsorption capacity (q(e) ≈ 200 mg/g) in all the pH range studied (from 3 to 11); even at low concentrations (C(e) ≈ 10 mg/L) and at short contact times (t(e) < 30 min).

A study of the relationship between process conditions and mechanical strength of mineralized red algae in the preparation of a marine-derived bone void filler.

Bone void fillers that can enhance biological function to augment skeletal repair have significant therapeutic potential in bone replacement surgery. This work focuses on the development of a unique microporous (0.5-10 microm) marine-derived calcium phosphate bioceramic granule. It was prepared from Corallina officinalis, a mineralized red alga, using a novel manufacturing process. This involved thermal processing, followed by a low pressure-temperature chemical synthesis reaction. The study found that the ability to maintain the unique algal morphology was dependent on the thermal processing conditions. This study investigates the effect of thermal heat treatment on the physiochemical properties of the alga. Thermogravimetric analysis was used to monitor its thermal decomposition. The resultant thermograms indicated the presence of a residual organic phase at temperatures below 500 degrees C and an irreversible solid-state phase transition from mg-rich-calcite to calcium oxide at temperatures over 850 degrees C. Algae and synthetic calcite were evaluated following heat treatment in an air-circulating furnace at temperatures ranging from 400 to 800 degrees C. The highest levels of mass loss occurred between 400-500 degrees C and 700-800 degrees C, which were attributed to the organic and carbonate decomposition respectively. The changes in mechanical strength were quantified using a simple mechanical test, which measured the bulk compressive strength of the algae. The mechanical test used may provide a useful evaluation of the compressive properties of similar bone void fillers that are in granular form. The study concluded that soak temperatures in the range of 600 to 700 degrees C provided the optimum physiochemical properties as a precursor to conversion to hydroxyapatite (HA). At these temperatures, a partial phase transition to calcium oxide occurred and the original skeletal morphology of the alga remained intact.

Thermal preparation of highly porous calcium phosphate bone filler derived from marine algae.

A sustainable marine-derived bioceramic with a unique porous structure has been developed for hard tissue repair. The conversion of alga was achieved through a novel technique, involving well controlled thermal processing followed by low pressure-temperature hydrothermal synthesis. In its preparation, a heat treatment step was required to remove the organic compounds from the algae, which reinforces the mineralised matrices. Its removal is necessary to prevent issue such as immune biocompatibility and ensure phase purity of the resultant biomaterial. This paper investigates the hydrothermal technique used for the transformation of mineralised red algae to hydroxyapatite that preserves the algae's unique structure. It specifically focuses on the effects of heat treatment on the morphology of the algae, TGA, SEM and hot stage XRD to quantity the changes.

The use of stomas in the early management of Hirschsprung disease: Findings of a national, prospective cohort study.

BACKGROUND/PURPOSE: Primary pull-through without a stoma has become preferred practice in managing Hirschsprung disease (HD). The aims of this study were to establish stoma rate and identify factors associated with stoma formation in a population-based cohort in the UK and Ireland. METHODS: Live-born infants with HD were prospectively identified in all 28 specialist pediatric surgical units in the UK and Ireland between October 2010 to September 2012. Method of colonic decompression was recorded and multivariable logistic regression was used to identify factors associated with stoma formation. RESULTS: 305 infants with HD were identified. Rectal washouts were initially used in 86% (263) with a defunctioning stoma formed as the primary management in 13% (39). Ultimately, 36% (111) required a stoma prior to definitive surgery. Compared to infants managed with rectal washouts alone; infants managed with a stoma were more likely to have a transition zone proximal to the splenic flexure, Down (or another) syndrome, and HD diagnosis established more than 28days after presentation. CONCLUSIONS: Although rectal washouts are commonly employed, a stoma prior to definitive surgery was required in 36% of infants in a national cohort. Delayed diagnosis, aganglionosis proximal to the splenic flexure and presence of other anomalies are associated with stoma formation. TYPE OF STUDY AND LEVEL OF EVIDENCE: Prognosis study (high-quality prospective cohort study with 80% follow-up and all patients enrolled at same time point in disease).

Hirschsprung's disease in the UK and Ireland: incidence and anomalies.

OBJECTIVES: To describe clinical characteristics and preoperative management of a national cohort of infants with Hirschsprung's disease (HD). DESIGN: Population-based cohort study of all live-born infants with HD born in the UK and Ireland from October 2010 to September 2012. SETTING: All 28 paediatric surgical centres in the UK and Ireland. PARTICIPANTS: 305 infants presenting before 6 months of age with histologically proven HD. MAIN OUTCOME MEASURES: Incidence, clinical characteristics including gestational age, birth weight, gender, associated anomalies; age and clinical features at presentation; and use of rectal washouts or stoma. RESULTS: The incidence of HD in the UK and Ireland was 1.8 per 10 000 live births (95% CI 1.5 to 1.9). Male to female ratio was 3.3:1. An associated anomaly was identified in 23% (69), with 15% (47) having a recognisable syndrome. The proportion of infants who presented and were diagnosed in the neonatal period was 91.5% (279) and 83.9% (256), respectively. 23.9% (73) and 44.2% (135) passed meconium within 24 and 48 hours of birth. 81% (246) first presented to a hospital without tertiary paediatric surgical services, necessitating interhospital transfer. Initial colonic decompression was by rectal washouts in 86.2% (263) and by defunctioning stoma in 12.8% (39). Subsequently, 27.4% (72) of infants failed management with rectal washouts and required a delayed stoma, resulting in 36.4% (111) of infants having a stoma. CONCLUSIONS: In this population-based cohort, presentation outside the neonatal period was rare. Nearly half of the infants with HD passed meconium within 48 hours of birth and over one third were managed with a stoma.

Treatment of hazardous shipyard wastewater using dolomitic sorbents.

Hazardous shipyard wastewater is a worldwide problem, arising from ship repair. In this study an experimental programme was undertaken to establish the suitability of dolomite and dolomitic sorbent materials to remove contaminants from wastewater arising from a commercial shipyard. Experimental data indicate that dolomite and dolomitic sorbents have the ability to significantly reduce the COD concentration of the shipyard effluent (98% reduction). The data gained from trials at a shipyard indicated that the dolomite treatment process could be undertaken in a 8000 L pilot scale reaction vessel. Analysis of the wastewater using ICP-MS during the pilot trial indicated that the dolomite significantly reduced the concentrations of metallic impurities. The concentration of Sn ions, which is indicative of organo-tin complexes commonly found in shipyard wastewater, was reduced by 80% from its initial concentration in the pilot trial. The mechanism for the removal process using dolomite has been ascribed to a metal complexation/sorption process.

Thermo-mechanical properties of poly ε-caprolactone/poly L-lactic acid blends: addition of nalidixic acid and polyethylene glycol additives.

The search for ideal biomaterials is still on-going for tissue regeneration. In this study, blends of poly ε-caprolactone (PCL) with poly l-lactic acid (PLLA), nalidixic acid (NA) and polyethylene glycol (PEG) were prepared. Mechanical and thermal properties of the blends were investigated by tensile and flexural analysis, DSC, TGA, WXRD, MFI, BET, SEM and hot stage optical microscopy. Results showed that the loading of PLLA caused a significant decrease in tensile strength and almost total eradication of the elongation at break of PCL matrix, especially after PEG and NA addition. Increased stiffness was also noted with additional NA, PEG and PLLA, resulting in an increase in the flexural modulus of the blends. Isothermal degradation indicated that bulk PCL, PLLA and the blends were thermally stable at 200°C for the duration of 2h making extrusion of the blends at this temperature viable. Morphological study showed that increasing the PLLA content and addition of the very low viscosity PEG and powder NA decreased the Melt Flow Indexer and increased the viscosity. At the higher temperature, the PLLA begins to soften and eventually melts allowing for increased flow and, coupling this with, the natural increase in MFI caused by temperature is enhanced further. The PEG and NA addition increased dramatically the pore volume which is important for cell growth and flow transport of nutrients and metabolic waste.

Breast biopsy. A comparison of outpatient and inpatient experience.

Nine hundred ninety-seven breast biopsies that were performed at one hospital over the five-year period from 1971 through 1975 were reviewed because of a changing pattern in the use of breast biopsies on outpatients who were under local anesthesia. In 1971, 17% of all breast biopsies were performed as outpatient procedures; by 1975, the figure was 60%. In 1971, 5% of all malignant neoplasms were diagnosed by the use of biopsies as outpatient procedures and 30% in 1975. Hospital charges for biopsy on an inpatient basis of benign breast disease were 7.2 times higher than for biopsy on an outpatient basis. Interviews of 102 patients clearly suggested that most patients were satisfied with the outpatient breast biopsy experience. Outpatient breast biopsy under local anesthesia is a safe procedure that is more economical in terms of medical cost, surgeons' time, and patients' time away from home and/or job. Preliminary biopsy of malignant lesions using local anesthesia permits more efficient use of diagnostic procedures to stage the extent of disease prior to treatment. Patient acceptance of breast biopsy as an outpatient procedure under local anesthesia was similar to their acceptance of biopsy on an inpatient basis under general anesthesia.

A rapid colorimetric assay of killer toxin activity in yeast.

The pale yellow redox indicator 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) is reduced to a dark blue end-product, MTT-Formazan, by the mitochondrial dehydrogenases of living cells. MTT reduction can be measured spectrophotometrically at a wavelength of 570 nm and a method is described to assay the cidal activity of Williopsis mrakii killer toxin against sensitive cells of Candida glabrata. The MTT assay is rapid, quantitative and compares favourably with traditional plating techniques for the assessment of sensitive viability.

Interactions between killer yeasts and pathogenic fungi.

A total of 17 presumptive killer yeast strains were tested in vitro for growth inhibitory and killing activity against a range of fungal pathogens of agronomic, environmental and clinical significance. Several yeasts were identified which displayed significant activity against important pathogenic fungi. For example, isolates of the opportunistic human pathogen, Candida albicans, were generally very sensitive to Williopsis mrakii killer yeast activity, whilst killer strains of Saccharomyces cerevisiae and Pichia anomala markedly inhibited the growth of certain wood decay basidiomycetes and plant pathogenic fungi. Results indicate that such yeasts, together with their killer toxins, may have potential as novel antimycotic biocontrol agents.

Prolonged two-man basic life support may result in hypocarbia in the ventilating rescuer.

OBJECTIVES: To determine whether the quality of expired air given during mouth-to-mouth ventilation differs between one- and two-person basic life support. METHODS: 15 young fit volunteers performed 15-min simulated resuscitation on a manikin. The oxygen and carbon dioxide concentration of their expired breath and the total ventilation was continuously monitored. Compression:ventilation ratios of 15:2 for one-person and 5:1 for two-person resuscitation were used. RESULTS: In two-man resuscitation, where the rescuer who is ventilating the patient is not performing chest compressions, the oxygen content of the expired breath rises (P<0.01), and the carbon dioxide content falls (P<0.01). The carbon dioxide concentration declined gradually throughout the 15-min session. Most participants complained of light-headedness on completion of the two-man session. Total ventilation did not differ between the two methods (P=0.757, 95% CI=-0.329, 0.242). CONCLUSION: Trainees in basic life support should be informed that symptoms of hypocarbia may occur in prolonged mouth-to-mouth ventilation, when acting in a two-man team. We would advise rescuers using these protocols to change places every 5 min to avoid these symptoms. These findings add further weight to the recommendations that all resuscitation should be carried out using 15:2 compression:ventilation ratio.

Paediatricians' perception of the use of extracorporeal membrane oxygenation to treat meconium aspiration syndrome.

This questionnaire study was designed to determine how consultant paediatricians perceived the value of extracorporeal membrane oxygenation (ECMO) in the treatment of meconium aspiration syndrome (MAS). A significant number believed that the survival of infants with MAS who received ECMO was lower than reported. Early discussion with an ECMO centre will ensure appropriate timing of referral.

Kinetics of a reactive dye adsorption onto dolomitic sorbents.

A novel wastewater treatment technique has been investigated, for reactive dye removal, in batch kinetic systems. These experimental studies have indicated that charred dolomite has the potential to act as an adsorbent for the removal of Brilliant Red reactive dye from aqueous solution. The effect of initial dye concentration, adsorbent mass:liquid volume ratio, and agitation speed on dye removal have been determined with the experimental data mathematically described using empirical external mass transfer and intra-particle diffusion models. The experimental data show conformity with an adsorption process, with the removal rate heavily dependent on both external mass transfer and intra-particle diffusion.

Biodegradation and biosorption of acid anthraquinone dye.

The acid anthraquinone dye Tectilon Blue (TB4R) is a major coloured component from the aqueous effluent of a carpet printing plant in Northern Ireland. The aerobic biodegradation of TB4R has been investigated experimentally in batch systems, using three strains of bacteria, namely, Bacillus gordonae (NCIMB 12553), Bacillus benzeovorans (NCIMB 12555) and Pseudomonas putida (NCIMB 9776). All three strains successfully decolourised the dye, and results were correlated using Michaelis-Menten kinetic theory. A recalculation of the reaction rate constants, to account for biosorption, gave an accurate simulation of the colour removal over a 24-h period. Up to 19% of the decolorisation was found to be caused by biosorption of the dye onto the biomass, with the majority of the decolorisation caused by utilisation of the dye by the bacteria. The reaction rate was found to be intermediate between zero and first order at dye concentrations of 200-1000 mg/l.

Fixed bed adsorption of acid dyes onto activated carbon.

The context of the study here is the adsorption of acid dyes from wastewater arising from a nylon carpet printing plant which currently receives no treatment. Since nylon is a particularly difficult fibre to dye, acid dyes are required for successful coloration. However, their presence, in high concentrations, in aqueous effluent arising from the plant can create major problems with respect to disposal. A treatment method based on adsorption onto granular activated carbon (GAC F400) in a fixed column configuration is described and breakthrough data of the dyes determined. The breakthrough data were correlated using a model based on liquid and pore diffusion with a good fit of experimental results obtained. Trends in the effective diffusivity used in the model correlated with other authors. A slight decrease in effective diffusivity was found with decrease in particle size and was attributed to interactions between the relatively large molecular sized dye and the microspore structure found in granular activated carbon.

Reconstructive surgery during Operations Just Cause and Desert Storm.

Operations Just Cause and Desert Storm were of relatively brief duration; however, severe wounds were produced that required complex reconstructive procedures. This paper describes the type of wounds managed in theater and subsequently at three U.S. military medical centers. Specific reconstructive techniques included local and free muscle, fasciocutaneous, and composite flaps. Emphasis is placed on the application of microsurgical techniques to battle-related injuries.

Biotechnological implications of the interactions between magnesium and calcium.

At the biochemical level, magnesium and calcium are known to act antagonistically towards each other. For example, many enzymes whose activities critically depend on sufficiency of intracellular magnesium, especially transphosphorylases, will be detrimentally affected by small increments in levels of cellular calcium ions. Growth of cells, cell division cycle progress and intermediary metabolism are also absolutely dependent on the bioavailability of magnesium, which can be compromised if excess calcium is present. Many biotechnological processes, therefore, which fundamentally exploit cellular growth and metabolism, will be influenced strongly by relative concentrations of the two cations and the ratio of bioavailable magnesium to calcium in external growth media. This paper surveys the interactive effects of magnesium and calcium at the bioinorganic level and discusses some examples of how these interactions may play important roles in governing the physiology of cells which are widely exploited in modern industrial bioprocesses.

A proposed method for the analysis of public health policy in less developed countries.

The study of public health policy in the less developed countries (LDCs) is handicapped by both lack of adequate data and gaps in conceptual apparatus. A new conceptual model is proposed that would be used for future policy analyses to assess what changes in health status of populations in LDCs can be expected as direct functions of increased health service resources, and of improved environmental and econosociocultural conditions. While direct policy analysis is ill-advised at this time due to data inadequacy, the model is illustrated using data presently available for twenty-five relatively homogeneous sub-Sahara African countries. Within the limitations of available data, the findings suggest that reductions in mortality in the region might best be achieved by making appropriate health resources available to the populations. Study findings also suggest that physicians contributed more during the study period to the variance in physical health status than did medical assistants.

Evolution in the management of Hirschsprung's disease in the UK and Ireland: a national survey of practice revisited.

INTRODUCTION: The management of Hirschsprung's disease continues to evolve. This questionnaire survey aimed to determine current surgical management strategies for Hirschsprung's disease in Britain. SUBJECTS AND METHODS: The survey was sent electronically to all British paediatric surgeons. Initial questions explored individual experience and regional service provision. Additional questions, reserved for surgeons who perform definitive Hirschsprung's disease surgery, addressed specific clinical scenarios. RESULTS: Surveys were sent to 142 surgeons yielding 85 responses. After exclusions, 64 surveys from 21 centres were analysed. Forty-seven respondents worked in centres with designated 'Hirschsprung's disease surgeons'. Forty respondents perform definitive Hirschsprung's disease surgery. In a well neonate with left-sided Hirschsprung's disease, 34 of 40 surgeons favour primary pull-through following bowel decompression with rectal washouts; 35 of 40 surgeons aim to perform definitive surgery at less than 3 months of age, with 17 favouring laparoscopic-assisted Soave-Boley and 15 favouring an open Duhamel pull-through. Of the 40 surgeons, 36 use a staged approach to right-sided/total colonic Hirschsprung's disease with 23 favouring a Duhamel or Long Duhamel pull-through. CONCLUSIONS: The primary pull-through, using an open Duhamel or laparoscopic-assisted Soave-Boley technique, during the first 3 months of life, has become the operative strategy of choice in rectosigmoid Hirschsprung's disease in Britain. Marked variation in practice remains for right-sided Hirschsprung's disease.