The development and applications of a micro-gap perforated electrode flow through cell

Electrochemical techniques provide convenient and environmentally compatible ways of bringing about chemical transformations. However they generally lose their economic viability when used with low conducting electrolyte systems. This has limited their usefulness in the treatment of water and wastewater. Increasing the electrolyte concentration of these systems is not an option as it is with industrial processes such as the chlor-alkali process. Cell resistance is the major limiting factor. Cell resistance can be reduced by reducing the inter-electrode gap. A novel micro gap perforated electrode flow through (PEFT) cell has been developed for efficient and cost effective treatment of aqueous systems of low ionic strength. The PEFT cell is an undivided flow through design which encompasses both parallel plate and porous electrode features. It consists of plate electrodes and flow is both through the electrodes and parallel to the surfaces of the two electrodes. The perforations in the electrodes and the short flow distance between the electrodes allow the inter-electrode gap to be reduced to 50 microns and less without causing excessive resistance to hydraulic flow. With reduced electrical resistance, effective electrochemical treatment of natural water and other low electrolyte systems is possible. The PEFT cell was first applied to overcome a local water supply problem, the Waikato region’s iron and manganese contaminated bore waters. These waters form stable colloidal suspensions during slow air oxidation. The problem can be overcome by rapid electrochemical oxidation using the PEFT cell. Electrochemical oxidation was found to be more effective and efficient than chemical oxidation allowing removal of iron and manganese to meet drinking water standards with minimal formation of disinfection by-products (DBP). Electrochemical oxidation of water and wastewater systems is brought about principally by chlorine mediated indirect oxidation processes. A 240 µm gap PEFT cell, with a graphite anode was used for chlorine generation. It produced chlorine at current efficiencies above 60% with an energy consumption of 4.83 kWh/kg of chlorine from a 0.5 mol/L NaCl solution. This result compares well with industrial hypochlorite production using an undivided cell. Chlorine mediated electro-oxidation of effluents was successfully demonstrated by the degradation of textile dyes in water. Complete single pass electrochemical decolourisation of indigo carmine (IC) dye effluent containing 0.35 mol/L NaCl was achieved using a graphite anode PEFT cell. Energy consumption was 0.8 kWh/m3 or 8.3 kWh/kg of dye. This is an order of magnitude less than the energy consumption reported for colour removal using graphite anodes. It is comparable or lower than most colour removal work carried out using metal oxide coated dimensionally stable anodes (DSAs) and boron doped diamond (BDD) anodes. Reduction of pH from 7 to 3 reduced the energy consumption for decolourisation of IC dye by 50% and also increased the TOC removal by 20%. When NaSO4 was used as the electrolyte rather than sodium chloride, colour removal was much less effective. A single pass through a 50 µm gap PEFT cell with a stainless steel cathode and a graphite anode operated at 5.5 V achieved a 6 log inactivation of Escherichia coli bacteria in a water sample containing only 1.7 mmol/L of chloride ions. The power consumption was 0.5 kWh/m3 of water. The narrow inter-electrode gap allows high electric fields to be produced from low applied voltages. When the cell was operated at above 5.0 volts, a synergistic electric field effect was observed. Specific lethality of the chlorine was increased to at least 50 L/(mgmin), approximately two orders of magnitude higher than in the absence of the field. Increased specific lethality means that disinfection can be achieved at much lower free available chlorine levels than previously possible. This reduces the risk of DBP formation. Improved current efficiencies and reduced energy consumption for electrolysis at low electrolyte concentrations were achieved by partial insulation of the active anode surface of a 50 µm gap PEFT cell. This electro-catalytic effect was consistent with enhanced transport of the electroactive species to the active part of the electrode, reducing concentration and resistance overpotentials. In the electrochemical production of chlorine from 0.85 mmol/L NaCl at a current density of 2 mA/cm2, current efficiency was tripled and power consumption was reduced by a factor of two, relative to the cell without the anode modification. The reduction in the inter-electrode gap to 50 µm and less has allowed the production of electric field strengths greater than 10 kV/cm from applied voltages of less than a 100V. Field strengths between 1and 10 kV/cm are known to cause reversible electroporation whereas irreversible electroporation occurs above 10 kV/cm. Evidence for irreversible electroporation was provided by the 6 log inactivation of Escherichia coli (in the absence of chlorine) at an applied electric field of 22.5 kV/cm generated in a 40 µm gap PEFT cell by a 90 V DC supply. The energy consumption was 430 J/mL and without cooling, the temperature remained below 42oC. Inactivation was achieved by 20 hydrodynamically generated DC pulses. The low applied voltage, the elimination of the need for pulsed electric fields, avoidance of external cooling and the simplicity of the experiment bring commercial non thermal electro-pasteurisation one step closer

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Synergistic electric field enhancement of the effectiveness of chlorine species formed during electrochemical disinfection of drinking water

In line in situ electrochemical disinfection of drinking water with chloride concentrations as low as 10 mg/L has been demonstrated at practical flow rates of at least 3 m3/day using a novel perforated electrode flow through (PEFT) cell with a 50 μm inter-electrode gap. Sufficient chlorine to achieve 6 log inactivation of Escherichia coli bacteria was produced at applied voltages as low as 5 V and with energy consumptions as low as 0.5 kWh/m3. At slightly higher applied voltages, the specific lethality of electrochemically produced chlorine was enhanced by at least two orders of magnitude to greater than 50 L/mg min. This dramatically enhanced lethality is consistent with a synergistic effect resulting from reversible electroporation when electric fields greater than 1.3 kV/cm are produced. There was no evidence for involvement of other species such as reactive oxygen species (ROSs). Disinfection of drinking water using the PEFT cell is cost competitive with other disinfection technologies and when enhanced by the electric field is much less likely to produce disinfection by products

A novel perforated electrode flow through cell design for chlorine generation

Chlorination remains a predominant method for disinfecting drinking water. Electrogeneration of chlorine has the potential to become the favoured method of chlorine production if costs can be lowered and chlorine generation efficiencies can be improved. A novel perforated electrode flow through (PEFT) cell design has been developed to address these problems. The electrodes were made from low-cost graphite sheets and stainless steel mesh and separated by a non-conducting fabric membrane. This electrode configuration allows reduction of electrode separation to 0.1 mm or less, minimizing cell resistance and increasing electrical efficiency. The new PEFT configuration generates hypochlorite from a 0.5 mol L⁻¹ brine at a current efficiency of better than 60%. As an inline in situ device, it produces chlorine concentrations known to be sufficient to disinfect water, from chloride concentrations as low as 0.004 mol L⁻¹ (available in most natural waters) by a single pass of the water through the cell operating at 11 V. The possibility of a portable device operated by a 12-V battery is indicated

A five-year prospective evaluation of a new community psychosis service in North London: introducing the Recovery and Enablement Track (RET)

Background and aims United Kingdom mental healthcare guidelines recommend recovery-focused services for people with psychosis. We evaluated a “Recovery and Enablement Track” (RET) aiming to promote recovery and well-being, reduce distress and maintain independence from secondary care following discharge, for people with established psychosis and long histories of secondary care. Method From March 2015 to December 2019, 214 individuals entered the RET and were followed up 12 months’ post-discharge. Recovery, well-being, and distress were measured at assessment, review, and discharge. Of 214 total people, 86 consented to inclusion for this evaluation. Results Well-being and recovery significantly improved from assessment to discharge – distress did not. Distress improved from review to discharge, suggesting improvement during service contact. 79% (68/86) of individuals were discharged to the care of their family doctor, and 22% of these (15/68) re-presented before 12-month follow-up. Conclusion Recovery and well-being improved from assessment to discharge, distress improved from review to discharge. Half of consenting participants were successfully discharged from secondary care following the RET, suggesting potential to promote recovery. Comparison to a formal control condition with systematic analysis of any biasing effect of missing data (i.e. through refusal to participate) is now indicated

Hemodynamic response to inhaled nitric oxide in patients with pulmonary hypertension and chronic kidney disease: A retrospective cohort study

Abstract Pulmonary hypertension (PH) associated with chronic kidney disease (CKD) (PH‐CKD) affects approximately 20%–40% of CKD patients and is associated with increased morbidity and mortality. PH and CKD are both pathophysiologically associated with nitric oxide (NO) deficiency. The NO pathway, an important therapeutic domain in pulmonary arterial hypertension (PAH), is an intriguing but unexplored target in PH‐CKD. We sought to improve understanding of the clinical significance of the NO pathway in patients with PH‐CKD by assessing the hemodynamic response to inhaled NO (iNO) during right heart catheterization (RHC). In this retrospective cohort study, patients with diagnosis codes of PH and stage IV/V CKD or end‐stage renal disease and estimated glomerular filtration rate  20 mmHg and pulmonary vascular resistance (PVR) > 3 Wood units were included. The final cohort included 37 patients (45.9% female, mean age 72.5 ± 9.7 years). A total of 56.7% of the cohort (21/37) had precapillary PH, while 43.2% (16/37) had combined precapillary postcapillary PH (Cpc‐PH). Median survival was 3.1 years after RHC. iNO was associated with a significant decrease in both mPAP and PVR. Hemodynamic changes in mPAP and PVR were similar in precapillary and Cpc‐PH groups. Among a small subset (n = 14) who were subsequently treated with PAH‐targeted therapy, treatment response was mixed and did not reveal significant benefit. Further studies are warranted to better define the potential role of PAH therapy in PH‐CKD

Breast surgeons' attitudes towards bilateral risk-reducing mastectomy: A National Survey of American Surgeons.

25 Background: Bilateral risk-reducing mastectomy (BRRM) confers the greatest risk-reduction in women at high-risk of developing breast cancer. Uptake of BRRM is influenced by the attitudes of these women as well as the breast surgeons offering these procedures. We surveyed surgeon members of the American Society of Breast Surgeons to assess their attitudes and knowledge. Methods: An International Cancer Risk Communication Study (InCRisC) questionnaire, previously used to assess attitudes of European physicians and surgeons was sent to 2648 members. Personal and occupational characteristics were recorded and knowledge of cancer genetics and attitudes to BRRM were assessed using clinical vignettes. Results: 439 breast surgeons responded. 98% of surgeons actively took a family history of the father. Almost 100% of surgeons reported a positive attitude towards BRRM. Female surgeons and those treating greater than 100 breast cancers a year were predictors of knowledge of breast cancer genetics and a positive attitude towards BRRM. Conclusions: Multiple factors contribute to surgeons' attitudes towards BRRM. Gender of surgeon and workload contribute to theses observed variations. </jats:p