Treatment of textile wastewaters using Eutectic Freeze Crystallization.

A water treatment process needs to recover both water and other useful products if the process is to be viewed as being financially and environmentally sustainable. Eutectic Freeze Crystallization (EFC) is one such sustainable water treatment process that is able to produce both pure ice (water) and pure salt(s) by operating at a specific temperature. The use of EFC for the treatment of water is particularly useful in the textile industry because ice crystallization excludes all impurities from the recovered water, including dyes. Also, EFC can produce various salts with the intention of reusing these salts in the process. This study investigated the feasibility of EFC as a treatment method for textile industry wastewaters. The results showed that EFC can be used to convert 95% of the wastewater stream to pure ice (98% purity) and sodium sulfate.

Improved calcium sulfate recovery from a reverse osmosis retentate using eutectic freeze crystallization.

A novel low temperature crystallization process called eutectic freeze crystallization (EFC) can produce both salt(s) and ice from a reverse osmosis (RO) stream by operating at the eutectic temperature of a solution. The EFC reject stream, which is de-supersaturated with respect to the scaling component, can subsequently be recycled back to the RO process for increased water recovery. This paper looks at the feasibility of using EFC to remove calcium sulfate from an RO retentate stream and compares the results to recovery rates at 0 and 20 °C. The results showed that there was a greater yield of calcium sulfate obtained at 0 °C as compared with 20 °C. Operation under eutectic conditions, with only a 20% ice recovery, resulted in an even greater yield of calcium sulfate (48%) when compared with yields obtained at operating temperatures of 0 and 20 °C (15% at 0 °C and 13% at 20 °C). The theoretical calcium recoveries were found to be 75 and 70% at 0 and 20 °C respectively which was higher than the experimentally determined values. The EFC process has the added advantage of producing water along with a salt.

Metal sulphides from wastewater: assessing the impact of supersaturation control strategies.

Metal sulphide precipitation forms an important component of acid mine drainage remediation systems based on bacterial sulphate reduction. However, the precipitation reaction is inherently driven by very high levels of supersaturation with the generation of small particles with poor solid-liquid separation characteristics. In this study, the effect of strategies used to manage supersaturation was investigated during copper and zinc sulphide precipitation reactions. Initial batch studies showed the origin of sulphide (biological or chemical) had no significant effect on the efficiency of zinc sulphide precipitation. For copper, low metal removal efficiency was obtained at metal to sulphide molar ratios below 1.6 in the synthetic sulphide system. This was improved in the biogenic sulphide system, due to the presence of residual volatile fatty acids, but the presence or absence of particulate organic matter had no effect on recovery. Subsequent studies, conducted using synthetic sulphide solutions in a seeded fluidised bed reactor with multiple reagent feed points (2FP and 6FP) and different recirculation flow rates (300 and 120 mL min(-1)) showed efficient zinc sulphide precipitation, but limited (<10%) deposition on the seeds. Increasing the number of sulphide feed points (2-6) reduced precipitate loss as fines by approximately 10%. Zinc sulphide fines could be effectively recovered from suspension by settling under quiescent conditions. In the copper system, metal recovery was low (ca 40%) due to the formation of very small copper sulphide particles (mean particle size of ca 0.01 µm). Increasing the number of reagent feed points did not affect supersaturation to the extent of altering particle characteristics. The copper sulphide fines could not be recovered by settling, remaining in a stable colloidal suspension due to their highly charged surfaces (zeta potential -50 mV). The change in recirculation flow rate had a limited effect (ca 5% improvement) on process efficiency. The results show that the extremely high supersaturation prevalent during metal sulphide precipitation is difficult to control using conventional approaches and suggest that the seeded fluidised bed reactor is not suitable for this application.

Effect of solution chemistry on particle characteristics during metal sulfide precipitation.

Metal sulfide precipitation forms an important component of acid mine drainage remediation systems based on bacterial sulfate reduction. The precipitation reaction is thermodynamically favorable, but a number of technical issues remain. In this study the effect of metal to sulfide molar ratio and operating pH on the nature and settling characteristics of copper and zinc sulfide precipitates was studied in a CSTR. A large number of small copper sulfide particles, with highly negatively charged surfaces and poor settling characteristics, were formed in the presence of a stoichiometric excess of sulfide at pH 6. The size and the settling characteristics of the particles were significantly improved, while the number of particles and magnitude of their zeta potential decreased when experiments were conducted at pH values <6. By comparison, for zinc sulfide, a small change in the number and size of the particles was observed for all metal to sulfide molar ratios and tested operating pH values. Precipitates generated at pH 6 had the most negative zeta potential, while operating at pH values <6 reduced the magnitude of the negative surface charge and improved the settling and dewatering characteristics of the precipitate. The data indicated that the amount of reactive sulfide species (HS(-) and S(2-) ions) available in solution during the precipitation process was important in determining the nature and surface characteristics of the particles produced and this was mainly dependent on pH.

The epidemiology of ocular trauma in rural Nepal.

AIMS: To estimate the incidence of ocular injury in rural Nepal and identify details about these injuries that predict poor visual outcome. METHODS: Reports of ocular trauma were collected from 1995 through 2000 from patients presenting to the only eye care clinic in Sarlahi district, Nepal. Patients were given a standard free eye examination and interviewed about the context of their injury. Follow up examination was performed 2-4 months after the initial injury. RESULTS: 525 cases of incident ocular injury were reported, with a mean age of 28 years. Using census data, the incidence was 0.65 per 1000 males per year, and 0.38 per 1000 females per year. The most common types of injury were lacerating and blunt, with the majority occurring at home or in the fields. Upon presentation to the clinic, 26.4% of patients had a best corrected visual acuity worse than 20/60 in the injured eye, while 9.6% had visual acuity worse than 20/400. 82% were examined at follow up: 11.2% of patients had visual acuity worse than 20/60 and 4.6% had vision worse than 20/400. A poor visual outcome was associated with increased age, care sought at a site other than the eye clinic, and severe injury. 3% of patients were referred for further care at an eye hospital at the initial visit; 7% had sought additional care in the interim between visits, with this subset representing a more severe spectrum of injuries. CONCLUSIONS: The detrimental effects of delayed care or care outside of the specialty eye clinic may reflect geographic or economic barriers to care. For optimal visual outcomes, patients who are injured in a rural setting should recognise the injury and seek early care at a specialty eye care facility. Findings from our study suggest that trained non-ophthalmologists may be able to clinically manage many eye injuries encountered in a rural setting in the "developing" world, reducing the demand for acute services of ophthalmologists in remote locations of this highly agricultural country.

Prioritising objectives for waste reprocessing: a case study in secondary lead refining.

Secondary lead refining produces a sulphidic slag that also contains varying quantities of lead. Initially, the objectives of this project were to treat the slag in order to recover the valuable lead as well as to render the slag environmentally benign. However, in keeping with the principles of clean technology and, specifically, the approach of clean production, the project was redefined with the following priorities: waste characterisation; waste minimisation through process improvement; waste modification; identification of slag treatment methods. Characterisation of the waste facilitated an overall process understanding and aided in identifying process deficiencies. Process improvement was aimed at reducing both the quantity of slag produced as well as the lead loss to the slag. Waste characterisation combined with local hazardous waste regulations enabled desirable waste modifications to be identified. These waste adaptations were implemented through process modification. Lastly, treatment methods for the slag were identified.

Oestrogen-induced apoptosis in colonocytes expressing oestrogen receptor beta.

Epidemiological studies of postmenopausal hormone replacement therapy show a reduction in the risk of developing colon cancer, and animal studies using 17beta-oestradiol (E(2)) demonstrate a decreased incidence of chemically-induced colon cancer. Using the colon cancer cell line, COLO205, we found that E(2) induced a dose-dependent increase in DNA fragmentation and nuclear condensation, significant effects being seen at 10(-12 )mol/l. BSA-conjugated E(2), which cannot enter cells, was ineffective at inducing apoptosis in COLO205 cells, indicating that E(2) was not acting through a cell-membrane receptor. E(2) did not induce the morphological changes characteristic of differentiation. Using RT-PCR we found that the oestrogen receptor alpha (ERalpha) isoform was absent in the COLO205 cell line in contrast to CACO-2, LoVo and SW620 cells, but mRNAs for ERbeta1, -beta2, -beta5 and -beta6 isoforms were detected. Western immunoblotting results showed full-length ERbeta protein but no detectable ERalpha in COLO205 cells. In normal human colon tissue samples immunoreactive ERbeta was found but ERalpha was barely detectable. Expression of ERbeta was lost in some colon cancer specimens and reduced in others. We conclude that E(2), through ERbeta, at concentrations found during replacement therapy, may inhibit the development of colon cancer by inducing apoptosis.

Reducing burnout: development of an oncology staff bereavement program.

PURPOSE/OBJECTIVES: To understand the necessity of providing a mechanism for staff bereavement that promotes stress reduction and enhances job longevity in the oncology nursing work environment and to describe the implementation of one such program. DATA SOURCES: Journal articles and on-site resources. DATA SYNTHESIS: Personnel conflicts, job dissatisfaction, and workplace burnout caused by constant patient loss are common in oncology nursing. The work setting must offer support for staff to deal with these conflicts to prevent burnout and decrease dissatisfaction. This can foster a sense of understanding among colleagues and provide support mechanisms for closure and acceptance of perpetual patient loss. CONCLUSION: Conflicts, dissatisfaction, and other sources of burnout must be contained so that oncology nurses remain in their vital roles. The potential for long-term professional fulfillment and improved quality of nursing care for patients and their families is increased by implementation of support mechanisms. IMPLICATIONS FOR NURSING PRACTICE: Educating colleagues about the multifaceted role of the oncology nurse can increase the staff's awareness of the need for support. Implementation of a program to reduce the stressors that oncology nurses encounter will encourage improved care delivery.

Thyroid heterotopia as a rare cause of intrapericardial tumoral mass case report and review of the literature.

This article describes the interesting discovery of a large tumoral mass formed of heterotopic thyroid tissue inside the pericardial cavity of an elderly man who died of unrelated causes. Heterotopic thyroid tissue may be found in many locations throughout the body. Intracardiac and intrapericardial locations, however, are exceptionally rare-this is only the second report of intrapericardial thyroid heterotopia. Such cases may be explained by the proximity of the developing cardiac structures and the foregut, the latter containing thyroid primordia during early embryogenesis.

Skin reactions to sunscreens.

Sunscreen reactions are said not to be uncommon. A population referred to a patch testing clinic was evaluated for reactions to sunscreen by questionnaire initially and then, if relevant, by patch testing to sunscreen products and their components. Irritant reactions were more common than allergic contact dermatitis. Allergic reactions to sunscreens were less common than to non-sunscreen chemicals present in sunscreen products.

The eastern Australian childhood nevus study: prevalence of atypical nevi, congenital nevus-like nevi, and other pigmented lesions.

BACKGROUND: Various melanocytic lesions are frequently observed. An understanding of phenotypic factors and environmental stimuli that are associated with these lesions may help explain their pathogenesis. OBJECTIVE: This study was undertaken to determine the prevalence of atypical nevi, blue nevi, cafe-au-lait macules, congenital nevus-like nevi, halo nevi, nevi spili, nevi 5 mm or more in diameter, and skin-colored melanocytic nevi in a population of schoolchildren and to explore risk factors including solar radiation in the development of these melanocytic lesions. METHODS: A cross-sectional study was performed by the same medical investigators to examine schoolchildren in three Australian cities that span a wide range of latitudes. RESULTS: Data from 1123 white Australian schoolchildren, 6 to 15 years of age, were analyzed. Acquired melanocytic nevi (atypical nevi, nevi > or = 5 mm in diameter, and skin-colored nevi) were more likely to develop in older fair-skinned subjects who had freckles and lived closest to the equator. Café-au-lait macules and congenital nevus-like nevi were observed in 36.3% and 4.4% of the total population, respectively. Prevalence for both these types of melanocytic lesions increased significantly with decreasing latitude. Halo nevi were present in 5.3% of the subjects and were usually solitary. These lesions were related to the presence of atypical nevi primarily by virtue of their size rather than of other features of clinical atypia. CONCLUSION: Like melanocytic nevi in general, large and atypical nevi are strongly influenced by geographic location and, by implication, degree of solar radiation. The same can be said for congenital nevus-like nevi, which suggests that many so-called congenital nevi are in fact acquired early in life.

Sunlight: a major factor associated with the development of melanocytic nevi in Australian schoolchildren.

BACKGROUND: Case-control studies have identified melanocytic nevi (MN) as the most important phenotypic risk factor for melanoma. A knowledge of any environmental factors that cause MN may facilitate prevention of melanoma. OBJECTIVE: This study was undertaken to explore the possible role of ambient solar irradiation in the development of MN in children. METHODS: With a standard protocol developed after international consultation, the same medical observers examined children in three Australian cities (Melbourne, Sydney, and Townsville) that span a wide range of latitude. RESULTS: A total of 1123 Australian schoolchildren 6, 9, 12, and 15 years of age were surveyed. Larger numbers of MN were found (mean 65.4 MN, standard deviation 52.9) than in previous studies of children. Prevalence increased with diminishing latitude (51.1 in Melbourne, 66.5 in Sydney and 77.2 in Townsville), particularly in children 6 and 9 years of age. Although nevus numbers were higher in children with light skin and hair, blue eyes, and freckling, the latitude gradient remained after adjustment for these and other factors in multivariate analysis. CONCLUSION: Latitude of residence, and by implication ambient UV radiation, is strongly related to nevus prevalence in young Australian children. However, these differences diminish with age and may disappear by 15 years of age.

Comparative evaluation of the Allergan Humphrey 570 and Canon RK-1 autorefractors: I. Objective autorefraction in normal subjects.

Fifty normal subjects were studied comparing objective autorefraction using the Allergan Humphrey 570 (AH 570) and Canon RK-1 autorefractors in terms of ease of operation, the time taken and their accuracy compared with clinical refraction. Both the autorefractors were equally easy to operate but the AH 570 was quicker. Objective autorefraction with the AH 570 was more accurate than using the Canon RK-1 especially with respect to spherical equivalence, sphere power and cyclinder axis: approximately 80% of the values were within 0.51 dioptres or 11 degrees of clinical refraction compared to approximately 60% for the Canon RK-1. The possible reasons for the superior performance of the AH 570 are discussed.

Comparative evaluation of the Allergan Humphrey 570 and Canon RK-1 autorefractors: II. Objective autorefraction in pseudophakes.

Fifty patients (50 eyes) with posterior chamber intraocular lenses and a best corrected visual acuity of at least 6/12 were studied. The Allergan-Humphrey 570 (AH-570) and Canon RK-1 autorefractors were compared in terms of ease of operation, time taken and their accuracy relative to clinical refraction. Both the autorefractors were equally easy to operate but the AH-570 was quicker. The AH-570 had a higher percentage of eyes within 11 degrees of clinically determined cylinder axis while the Canon RK-1 had a higher percentage of patients within 0.51 diopters of spherical equivalence, sphere power and cylinder power as determined by clinical refraction. This difference in the accuracy of objective autorefraction was not statistically significant; the clinical significance is uncertain.

Clinical evaluation of automated refraction in anterior chamber pseudophakia.

Automated refraction with the Canon RK-1 Autoref keratometer was evaluated in 85 eyes of 85 patients with an anterior chamber intraocular lens implant and a best corrected visual acuity of at least 6/12. Autorefraction readings were obtained in 80 (94%) of these eyes. The agreement between autorefraction and clinical refraction data was 89% for spherical equivalence less than 0.51 dioptres (D), 91% for sphere power less than 0.51 D, 82% for cylinder power less than 0.51 D, and 91% for cylinder axis less than 11 degrees. Autorefraction provides acceptably accurate postoperative refraction values in anterior chamber pseudophakia.

Monocyte function in rhesus monkeys with simian acquired immune deficiency syndrome.

Monocyte function in rhesus monkeys with simian acquired immune deficiency syndrome (SAIDS) was compared with that in age-matched normal juvenile rhesus monkeys. The functional tests were 1) chemotaxis, 2) phagocytosis of opsonized Candida albicans, 3) killing and/or growth inhibition of Candida albicans, 4) generation of respiratory burst, and 5) monocyte-derived macrophage response (morphology and/or respiratory burst) to stimulating agents such as lymphokines, gamma interferon, endotoxin, and phorbol myristate acetate. The monkeys tested had either clinical SAIDS (alive with lymphadenopathy, splenomegaly, and lymphopenia or neutropenia) or had terminal SAIDS (moribund due to the disease). Responses of monocytes from 14 monkeys with clinical SAIDS were indistinguishable from those of 9 normal juvenile rhesus monkeys, whereas monocytes from 3 monkeys with terminal SAIDS had enhanced phagocytosis and respiratory burst capacity. Chemotaxis, candidacidal/stasis activity, and response to stimulating agents were normal in these terminal cases. Plasma from the SAIDS monkeys was as capable of opsonizing yeasts and of being able to generate chemotactic factors by endotoxin as was control plasma. SAIDS retrovirus (SRV) was detected by co-cultivation of pure monocyte-derived macrophage cultures with Raji cells, an indicator cell line which forms syncytia in the presence of SRV. Four terminal SAIDS cases and one late-stage clinical SAIDS case were virus-positive when the number of macrophages in the cultures ranged from less than 50 to about 500. Terminal SAIDS monocyte-derived macrophages in culture as long as 17 days produced SRV. These data show that in monkeys with SAIDS the major effector functions of monocytes and macrophages involved in host defense are intact (even up until death). Additionally, some of the monocytes are productively infected, and these infected monocytes are viable and adherent in culture.

Role of autoantibodies in the autoimmune response to testis in rainbow trout (Salmo gairdneri).

Rainbow trout, Salmo gairdneri, passively immunized with anti-sperm antibodies developed lesions in the testis characteristic of autoimmune attack. Only animals pre-treated with Freund's complete adjuvant developed these lesions. Investigations into the possible role of autoantibodies during autoimmune attack, carried out in vitro, showed that sperm antibodies were not cytotoxic but did have an opsonic effect on macrophage phagocytosis of sperm in the presence of complement.

Angiogenesis induced by "normal" human breast tissue: a probable marker for precancer.

Normal human breast lobules, freshly isolated by precision microdissection of tissue stained with methylene blue chloride, were assayed for their ability to induce neovascularization (angiogenesis) in rabbit irises. Histologically, normal lobules from cancerous breast induced angiogenesis twice as often as lobules from noncancerous breasts, suggesting that preneoplastic transformation is diffuse.