Sustainable removal of N2O by mediated electrocatalytic reduction at ambient temperature electro-scrubbing using electrogenerated Ni(I) electron mediator

Direct catalysis is generally proposed for nitrous oxide (N₂O) abatement but catalysis is expensive, requires high temperatures, and suffers from media fouling, which limits its lifetime. In the present study, an ambient temperature electroscrubbing method was developed, coupling wet-scrubbing with an electrogenerated Ni(I) ([Ni(I)(CN)₄]^3-) mediator, to enable N₂O reduction in a single process stage. The initial studies of 10 ppm N₂O absorption into 9 M KOH and an electrolyzed 9 M KOH solution showed no removal. However, 95% N₂O removal was identified through the addition of Ni(I) to an electrolyzed 9 M KOH. A change in the oxidation/reduction potential from -850 mV to -650 mV occurred following a decrease in Ni(I) concentration from 4.6 mM to 4.0 mM, which confirmed that N₂O removal was mediated by an electrocatalytic reduction (MER) pathway. Online analysis identified the reaction product to be ammonia (NH₃). Increasing the feed N₂O concentration increased NH₃ formation, which suggests that a decrease in electrolyzed solution reactivity induced by the increased N₂O load constrained the side reaction with the carrier gas. Importantly, this study outlines a new regenerable method for N₂O removal to commodity product NH₃ at ambient temperature that fosters process intensification, overcomes the limitations generally observed with catalysis, and permits product transformation to NH₃.

Energy recovery from human faeces via gasification: A thermodynamic equilibrium modelling approach

Non-sewered sanitary systems (NSS) are emerging as one of the solutions to poor sanitation because of the limitations of the conventional flush toilet. These new sanitary systems are expected to safely treat faecal waste and operate without external connections to a sewer, water supply or energy source. The Nano Membrane Toilet (NMT) is a unique domestic-scale sanitary solution currently being developed to treat human waste on-site. This toilet will employ a small-scale gasifier to convert human faeces into products of high energy value. This study investigated the suitability of human faeces as a feedstock for gasification. It quantified the recoverable exergy potential from human faeces and explored the optimal routes for thermal conversion, using a thermodynamic equilibrium model. Fresh human faeces were found to have approximately 70-82 wt.% moisture and 3-6 wt.% ash. Product gas resulting from a typical dry human faeces (0 wt.% moisture) had LHV and exergy values of 17.2 MJ/kg and 24 MJ/kg respectively at optimum equivalence ratio of 0.31, values that are comparable to wood biomass. For suitable conversion of moist faecal samples, near combustion operating conditions are required, if an external energy source is not supplied. This is however at 5% loss in the exergy value of the gas, provided both thermal heat and energy of the gas are recovered. This study shows that the maximum recoverable exergy potential from an average adult moist human faeces can be up to 15 MJ/kg, when the gasifier is operated at optimum equivalence ratio of 0.57, excluding heat losses, distribution or other losses that result from operational activities.

The cost of a small membrane bioreactor

The individual cost contributions to the mechanical components of a small membrane bioreactor (MBR) (100-2,500 m3/d flow capacity) are itemised and collated to generate overall capital and operating costs (CAPEX and OPEX) as a function of size. The outcomes are compared to those from previously published detailed cost studies provided for both very small containerised plants (<40 m3/day capacity) and larger municipal plants (2,200-19,000 m3/d). Cost curves, as a function of flow capacity, determined for OPEX, CAPEX and net present value (NPV) based on the heuristic data used indicate a logarithmic function for OPEX and a power-based one for the CAPEX. OPEX correlations were in good quantitative agreement with those reported in the literature. Disparities in the calculated CAPEX trend compared with reported data were attributed to differences in assumptions concerning cost contributions. More reasonable agreement was obtained with the reported membrane separation component CAPEX data from published studies. The heuristic approach taken appears appropriate for small-scale MBRs with minimal costs associated with installation. An overall relationship of net present value=(a tb)Q(-c lnt+d) was determined for the net present value where a=1.265, b=0.44, c=0.00385 and d=0.868 according to the dataset employed for the analysis.

Reflux composition influences the level of NF-κB activation and upstream kinase preference in oesophageal adenocarcinoma cells

Oesophageal adenocarcinoma (OA) incidence is rising and prognosis is poor. Understanding the molecular basis of this malignancy is key to finding new prevention and treatment strategies. Gastroesophageal reflux disease is the primary cause of OA, usually managed with acid suppression therapy. However, this often does little to control carcinogenic bile acid reflux. The transcription factor nuclear factor kappa B (NF-κB) plays a key role in the pathogenesis of OA and its activity is associated with a poor response to chemotherapy, making it an attractive therapeutic target. We sought to decipher the role of different bile acids in NF-κB activation in oesophageal cell lines using short, physiologically relevant exposure times. The effect of an acidic or neutral extracellular pH was investigated concurrently, to mimic in vivo conditions associated with or without acid suppression. We found that some bile acids activated NF-κB to a greater extent when combined with acid, whereas others did so in its absence, at neutral pH. The precise composition of an individual's reflux, coupled with whether they are taking acid suppressants may therefore dictate the extent of NF-κB activation in the oesophagus, and hence the likelihood of histological progression and chemotherapy success. Regardless of pH, the kinase inhibitor of κB kinase was pivotal in mediating reflux induced NF-κB activation. Its importance was confirmed further as its increased activation was associated with histological progression in patient samples. We identified further kinases important in acid or bile induced NF-κB signalling in oesophageal cells, which may provide suitable targets for therapeutic intervention.

Inducible nitric oxide synthase (iNOS) and nitric oxide (NO) are important mediators of reflux-induced cell signalling in esophageal cells

Nitric oxide (NO) produced by inducible nitric oxide synthase (iNOS) has been implicated in both DNA damage induction and aberrant cell signalling in various tissue and cell backgrounds. We investigated here the role of iNOS and NO in DNA damage induction and nuclear factor-kappa B (NF-κB) signalling in esophageal cells in vitro. As esophageal adenocarcinoma develops in a background of Barrett's esophagus secondary to reflux disease, it is possible that inflammatory mediators like NO may be important in esophageal cancer development. We show that reflux components like stomach acid and bile acids [deoxycholic acid (DCA)] can induce iNOS gene and protein expression and produce NO generation in esophageal cells, using real-time PCR, western blotting and NO sensitive fluorescent probes, respectively. This up-regulation of iNOS expression was not dependent on NF-κB activity. DCA-induced DNA damage was independent of NF-κB and only partially dependent on iNOS and NO, as measured by the micronucleus assay. These same reflux constituents also activated the oncogenic transcription factor NF-κB, as measured by transcription factor enzyme-linked immunosorbent assay and gene expression studies with NF-κB linked genes (e.g. interleukin-8). Importantly, we show here for the first time that basal levels of NF-κB activity (and possibly acid and DCA-induced NF-κB) are dependent on iNOS/NO and this may lead to a positive feedback loop whereby induced iNOS is upstream of NF-κB, hence prolonging and potentially amplifying this signalling, presumably through NO activation of NF-κB. Furthermore, we confirm increased protein levels of iNOS in esophageal adenocarcinoma and, therefore, in neoplastic development in the esophagus.

Human papillomavirus infection in Barrett's oesophagus in the UK: an infrequent event

BACKGROUND

Human papillomavirus (HPV) infection has been reported in squamous cell carcinomas of the oesophagus and has been recently described in Barrett's oesophagus, a premalignant condition which may give rise to oesophageal adenocarcinoma.

OBJECTIVES

To investigate HPV infection in Barrett's oesophagus in a UK population.

STUDY DESIGN

DNA was extracted from 73 Barrett's oesophagus biopsies and examined for the presence of DNA for 14 high risk (HR) and 6 low risk (LR) HPV types.

RESULTS

HPV DNA was present in only 1 of 73 samples; genotyping indicated this was a high risk type 51 infection.

CONCLUSIONS

HPV infection appears unlikely to be a significant factor in the aetiology of Barrett's oesophagus in the UK.

Brief negotiation program for promoting behavior change: the Kaiser Permanente approach to continuing professional development

BACKGROUND

Behavior change counseling is one of the most difficult and constant challenges faced by health providers. It has a significant impact on clinical outcomes as well as patient and provider satisfaction. By encouraging patients to participate in a partnership with health care professionals, Brief Negotiation offers techniques to motivate behavior change successfully. We review the key components of Brief Negotiation and describe how one large group model health maintenance organization was able to identify key staff members, develop educational opportunities and implement Brief Negotiation system-wide into standard care practices.

OBJECTIVES

To expose a maximum number of health care professionals to a recommended model of behavior change counseling; to increase the satisfaction and confidence of health care professionals in counseling for behavior change; and to increase the likelihood of improved patient health outcomes.

METHOD

Two departments created one-day, two-day, six-hour and one-to-two-hour skill-based programs targeted to physicians, nurse practitioners, care managers, clinical health educators, behavioral medicine specialists, physical therapists, pharmacists and medical assistants. Practice protocols, strategic departmental alliances and intranet sites complemented the educational interventions.

RESULTS

Over 1000 health care professionals have been exposed to the Brief Negotiation model in over two years. A mailed survey to graduates of the one- and two-day programs indicated that 67% of physicians and 79% of other health professionals felt more confident about working with patients on behavior change after having attended the Brief Negotiation program.

CONCLUSIONS

System-wide professional development requires multiple exposures to the Brief Negotiation model, considerable resources for curriculum development, training time and follow-up, and credible clinical trainers. Questions remain about the amount of training needed for long-term clinician behavior change and for improved health outcomes in patients.

Effects of providing hospital-based doulas in health maintenance organization hospitals

OBJECTIVE

To evaluate whether providing doulas during hospital-based labor affects mode of delivery, epidural use, breast-feeding, and postpartum perceptions of the birth, self-esteem, and depression.

METHODS

This was a randomized study of nullipara enrollees in a group-model health maintenance organization who delivered in one of three health maintenance organization-managed hospitals; 149 had doulas, and 165 had usual care. Study data were obtained from the mothers' medical charts, study intake forms, and phone interviews conducted 4-6 weeks postpartum.

RESULTS

Women who had doulas had significantly less epidural use (54.4% versus 66.1%, P < .05) than women in the usual-care group. They also were significantly (P < .05) more likely to rate the birth experience as good (82.5% versus 67.4%), to feel they coped very well with labor (46.8% versus 28.3%), and to feel labor had a very positive effect on their feelings as women (58.0% versus 43.7%) and perception of their bodies' strength and performance (58.0% versus 41.0%). The two groups did not differ significantly in rates of cesarean, vaginal, forceps, or vacuum delivery, oxytocin administration; or breast-feeding, nor did they differ on the postpartum depression or self-esteem measures.

CONCLUSION

For this population and setting, labor support from doulas had a desirable effect on epidural use and women's perceptions of birth, but did not alter need for operative deliveries.