Struvite precipitation within wastewater treatment: A problem or a circular economy opportunity?

Enhanced biological phosphorus removal at wastewater treatment plants that use anaerobic digesters for sludge treatment have historically encountered phosphate precipitation problems in the form of struvite. Literature on struvite is thin which is surprising given it can foul/block the sludge return lines and associated pumps and valves, causing significant operational problems. This study has evaluated if a typical large wastewater treatment plant can overcome this problem by adopting circular economy thinking. The struvite profile based on the supersaturation ratio of (Mg:NH4:PO4 2-), pH and temperature demonstrates the potential operational hotspots that can present uncontrolled struvite formation. Based on current struvite monitoring technologies and a cost-benefit analysis, the controlled struvite recovery via an Ostara crystallization reactor has been demonstrated to be economically viable with a pay-back period of less than a decade. An integrated evaluation illustrates the positive environmental impact arising from the utilisation of the recovered product. Economic viability and payback periods will vary according to circumstances, but we recommend that WWTP operators globally consider fitting a crystallisation reactor to appropriate plants, The outcomes and recommendation from this study are particularly timely given the global fertiliser shortage (2022) that is driving up food prices and reducing crop sizes.

Adolescent emotional response to music and its relationship to risk-taking behaviors.

PURPOSE: Adults have frequently been concerned about the adverse influence that music may have on teenagers. This study was designed to examine the relationship between the intensity of emotional response to music and health risk-taking behavior in adolescents. METHODS: Consecutive participants from the University of California, San Diego, Adolescent Medicine Clinics completed a written survey about music preference, emotional response to music using the Positive Affect Negative Affect Schedule (PANAS), and a variety of health-risk behaviors. For each participant, the PANAS scores were summed to give a positive, negative, and total affect score, and health-risk behaviors were assigned a point value based on the level of risk and then summed to give a risk score. RESULTS: Health-risk behavior was found to be correlated with increasing emotional response to music (r = 0.23), whether those emotions were positive (r = 0.19) or negative (r = 0.24). Strong negative emotional response to music in particular was correlated with a history of greater risk behavior, particularly among whites (risk score = 14.0). CONCLUSIONS: Our study indicates that subjects who experience strong negative emotions to music are at an increased risk of participating in a variety of risk-taking behaviors. Further evaluation of the link between emotional response to music and health-risk behaviors will be useful in clarifying the nature of this relationship.

An improved process for development and testing of vena caval filters: the percutaneous steel Greenfield filter.

BACKGROUND: The purpose of this study was to develop a reduced profile stainless steel Greenfield filter with an over-the-wire delivery system and to compare its performance with the existing Food and Drug Administration-approved Greenfield filters. In addition, we wanted to standardize a system for evaluating filter prototypes. METHODS: Percutaneous stainless steel filters with various hook configurations were evaluated for efficacy and safety in four in vitro modules designed to reproduce potential liabilities experimentally. Animal studies to assess thrombus capture and resolution, filter stability, migration, and hemodynamics were completed in 4 dogs and 38 sheep. RESULTS: Mathematical modeling suggested that hook angle was the most relevant factor in improving resistance to migration. Prototypes that varied with respect to hook length and angle were evaluated in both the in vitro testing unit and in sheep. The stainless steel filter with two downward directed hooks provided clot capture comparable with the current Greenfield filter, maintenance of flow, and resistance to fatigue and corrosion while providing significant resistance to migration and penetration (p < 0.05). CONCLUSIONS: The percutaneous stainless steel Greenfield filter with the alternating hook design provides a reduced profile device that can be placed over a wire to improve positioning. The use of a standardized testing system reduced both the time and cost of bringing this new device to the market.

Radioimmunoscintigraphy of squamous carcinomas of the head and neck.

A pilot study was carried out to assess the value of a radiolabeled antibody against epidermal growth factor receptor (EGFR1) in localizing tumors in patients with squamous carcinomas of the head and neck. Positive images of large tumours (greater than 3 cm diameter) were obtained in 8 of 11 patients after intravenous administration of 111indium-labeled EGFR1. Two patients gave equivocal results, while negative scans were obtained from the patient with the smallest tumor (1 cm diameter). There were no false-positive images. The success of this study in localizing relatively large squamous carcinomas indicates that the antibody should be evaluated in patients with smaller tumors to establish the limits of detection of the technique.

The effect of chelating agents on the distribution of monoclonal antibodies in mice.

The potential for altering the biodistribution of radiolabel from gallium- and indium-labeled mouse monoclonal antibodies was investigated in mice using metal chelating agents. The chelating agents used were desferrioxamine (DFO), diethylenetriaminepentaacetic acid (DTPA), ethylenediamine-di (O-hydroxyphenylacetic acid) (EDHPA), and 2,2' dipyridyl (DIPY). The mouse monoclonal antibody LICR-LON-M8 was labeled with 111In after conjugation to DTPA, and with 67Ga after conjugation to DFO. All the chelating agents except DIPY altered the biodistribution of [67Ga]citrate and [111In]citrate but did not affect the 48-hr tissue uptake of label from [111In]DTPA-M8 or [67Ga]DFO-M8, confirming the in vivo stability of the antibody conjugates. Label fixed in the tissues was inaccessible to the chelating agents, indicating that they will not be suitable for reducing the high background liver radioactivity in patients undergoing scanning with indium-labeled antibodies.

An antibody-desferrioxamine conjugate labelled with 67Ga.

The optimum conditions for producing a 67Ga labelled antibody-desferrioxamine conjugate were determined. The mouse monoclonal antibody LICR-LON-M8 was coupled to the metal chelating compound desferrioxamine (DFO) using glutaraldehyde (GLUT). A DFO:GLUT:M8 molar ratio of 500:150:1 gave an immunoreactive antibody with low amounts (less than 5%) of high molecular weight polymer. The labelling efficiency with 67 Ga was greater than 90%, with a specific activity of 2-4 MBq/mg antibody. This 67Ga labelled antibody is suitable for evaluation as a diagnostic imaging agent.

In vitro uptake of gallium and chlorpromazine by mouse tumour cells.

Primary cell suspensions were prepared from mouse sarcoma by enzymatic digestion with pronase. The cells were incubated with gallium citrate Ga 67 or the basic drug 14C-chlorpromazine (CPZ) for up to 1 h at 37 degrees C, and the label uptake was determined. The Ga uptake was proportional to time (0-30 min), whilst the CPZ uptake rapidly reached apparent saturation (less than 10 min). Metabolic inhibitors did not affect label uptake; however, disrupting the cell membrane with N-ethylmaleimide or heating at 56 degrees C significantly reduced CPZ accumulation but did not inhibit Ga uptake. Ga accumulation was decreased by adding human transferrin (0.5 mg/ml). Both gallium and chlorpromazine are fixed in the lysosomes of cells; however, in this system, they appeared to enter mouse sarcoma cells by different energy-independent mechanisms. The Ga uptake may reflect adsorption to cell components, whilst CPZ uptake required an intact cell and may be due to passive diffusion.

Phosphoenolpyruvate-dependent glucose phosphotransferase activity in Streptococcus mitis ATCC 903.

A constitutive phosphoenolpyruvate (PEP)-dependent glucose phosphotransferase system was found in decryptified cells of Strep. mitis. The system displayed saturation kinetics and the apparent Km value for the non-fermentable analogue 2-deoxyglucose (2DG) was 0.4 mM. Sodium fluoride inhibited the activity when 2-phosphoglycerate was used as the energy source instead of PEP. Intact cells accumulated 2DG and also a derivative that behaved chromatographically like 2DG-6-phosphate. PEP-dependent glucose phosphotransferase activity was also demonstrated in freshly collected plaque.

Effects of 2-deoxy D-glucose and other sugar analogues on acid production from sugars by human dental plaque bacteria.

Solutions (10-25 microM) of D-glucose, N-acetyl-D-glucosamine, D-fructose, sucrose, maltose, lactose and maltotriose were readily metabolised to acid (140-250 mumol H+ wet g-1h-1) by anaerobic suspensions of fresh plaque at pH 7.5. D-Mannose, D-galactose, D-glucosamine and trehalose were broken down more slowly (35-115 mumol H+ wet g-1h-1). Inhibition of this acid production occurred on adding excess amounts of 2-deoxy-D-glucose or 5-thio-D-glucose. Similarly, excess amounts of cellobiose specifically inhibited acid liberation from lactose. No acid production was detected from a number of other sugars and sugar derivatives, some of which may be useful sucrose substitutes.

A combined three-year and four-year medical program with modified admission requirements.

More flexible admission requirements have made it possible to admit students to the first year of a program leading to the B.Med.Sc. degree at the end of two years and to the M.D. degree in four years, saving one to three years by means of earlier entry following high school. More advanced students may enter at the beginning of second year and complete a three-year M.D. program. Encouraging preliminary results have been obtained.