m-s-m cationic gemini and zwitterionic surfactants – a thermodynamic analysis of their mixed micelle formation

Micelle formation enthalpies (Δ_micH values) have been calorimetrically determined at 298 K for three sets of mixed zwitterionic/cationic gemini systems consisting of N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (ZW3-12) and a series of structurally related gemini surfactants, the N,N''-bis(dimethyldodecyl)-α,ω-alkanediammonium dibromide (12-s-12) systems. From the experimental and the estimated ideal micelle formation enthalpies, the excess enthalpies were obtained. The degrees of nonideality of the interaction in the mixed micelle (β^m) from our previous work was used along with the excess enthalpy values to determine excess thermodynamic quantities of the surfactants in the mixed system according to Regular Solution Theory (RST) and Motomura''s theory. The excess enthalpies for the ZW3-12/12-4-12 were positive in magnitude and rose sharply when small amounts of the zwittergent were distributed into the gemini micelles. The excess enthalpies for the ZW3-12/12-5-12 and the ZW3-12/12-6-12 systems were also >0 kJ mol⁻¹, and as a function of zwittergent composition, were quite different to those of the ZW3-12/12-4-12 mixed micelles. These results indicate that the heat of mixed micelle formation is strongly dependent on electrostatic interactions and the structure of the surfactants involved, specifically, the length of the tether group for the 12-s-12 gemini surfactants. From the calorimetric data and the application of RST and Motomura''s theory, we have obtained estimates of the excess Gibbs energy and entropy of mixing. An analysis of the three thermodynamic properties suggests that the relative contributions of enthalpic and entropic effects to nonideal behavior for mixed micelles involving gemini surfactants are strongly dependent on the gemini structure.

Excess enthalpies of micelle formation for the ZW3-12/12-s-12 system as a function of the mole fraction of zwittergent (α_ZW3-12).     

Coping with the personal loss of having a parent with mental illness: young adults' narrative accounts of spiritual struggle and strength

The present study examines the personal accounts of nine young adults who have parents living with mental illness. Adults' experience of personal loss due to their parents' mental illness and perceptions of their religious faith journey and spiritual struggles are described. Overall, young adults who reported experiencing more personal loss due to their parents' mental illness also reported feeling more confused on their faith journey, and reported experiencing more spiritual struggle relative to participants who reported experiencing less personal loss. Regardless of level of personal loss, all participants identified positive personal attributes that resulted from coping with their parents' illness, including a greater sense of independence, personal strength, and compassion. © 2010 Wiley Periodicals, Inc.     

Legionella jordanis lower respiratory tract infection: case report and review

Legionella jordanis was first described in 1982 after isolation from environmental sources and is otherwise a very rare human pathogen. Here, we report the recovery of L. jordanis from a bronchoalveolar lavage specimen from a patient who presented with an indolent lower respiratory tract infection associated with constitutional symptoms. This case is the first culture-positive case of infection involving this species in Canada.     

Gardnerella vaginalis bacteremia in a previously healthy man: case report and characterization of the isolate

Gardnerella vaginalis in women causes vaginitis or infections in other sites, such as the urinary tract, but is an infrequent cause of bacteremia. Bacteremia in men is very rare and is typically associated with immunocompromised states. Here we describe G. vaginalis bacteremia in a previously healthy man with renal calculi and urosepsis.     

BeLieving in Native Girls: characteristics from a baseline assessment

BeLieving In Native Girls (BLING) is a juvenile delinquency and HIV intervention at a residential boarding school for American Indian/Alaska Native adolescent girls ages 12-20 years. In 2010, 115 participants completed baseline surveys to identify risk and protective factors. Initial findings are discussed regarding a variety of topics, including demographics and general characteristics, academic engagement, home neighborhood characteristics and safety, experience with and perceptions of gang involvement, problem-solving skills, self-esteem, depression, sexual experiences and risk-taking behaviors, substance abuse, and dating violence.     

Drug-resistance mechanisms in Vibrio cholerae O1 outbreak strain, Haiti, 2010

To increase understanding of drug-resistant Vibrio cholerae, we studied selected molecular mechanisms of antimicrobial drug resistance in the 2010 Haiti V. cholerae outbreak strain. Most resistance resulted from acquired genes located on an integrating conjugative element showing high homology to an integrating conjugative element identified in a V. cholerae isolate from India.     

Reproductive health services in Malawi: an evaluation of a quality improvement intervention

Objective

this study was to evaluate the impact of a quality improvement initiative in Malawi on reproductive health service quality and related outcomes.

Design

(1) post-only quasi-experimental design comparing observed service quality at intervention and comparison health facilities, and (2) a time-series analysis of service statistics.

Setting

sixteen of Malawi's 23 district hospitals, half of which had implemented the Performance and Quality Improvement (PQI) intervention for reproductive health at the time of the study.

Participants

a total of 98 reproductive health-care providers (mostly nurse–midwives) and 139 patients seeking family planning (FP), antenatal care (ANC), labour and delivery (L&;D), or postnatal care (PNC) services.

Intervention

health facility teams implemented a performance and quality improvement (PQI) intervention over a 3-year period. Following an external observational assessment of service quality at baseline, facility teams analysed performance gaps, designed and implemented interventions to address weaknesses, and conducted quarterly internal assessments to assess progress. Facilities qualified for national recognition by complying with at least 80% of reproductive health clinical standards during an external verification assessment.

Measurements

key measures include facility readiness to provide quality care, observed health-care provider adherence to clinical performance standards during service delivery, and trends in service utilisation.

Findings

intervention facilities were more likely than comparison facilities to have the needed infrastructure, equipment, supplies, and systems in place to offer reproductive health services. Observed quality of care was significantly higher at intervention than comparison facilities for PNC and FP. Compared with other providers, those at intervention facilities scored significantly higher on client assessment and diagnosis in three service areas, on clinical management and procedures in two service areas, and on counselling in one service area. Service statistics suggest that the PQI intervention increased the number of Caesarean sections, but showed no impact on other indicators of service utilisation and skilled care.

Conclusions

the PQI intervention showed a positive impact on the quality of reproductive health services. The effects of the intervention on service utilisation had likely not yet been fully realized, since none of the facilities had achieved national recognition before the evaluation. Staff turnover needs to be reduced to maximise the effectiveness of the intervention.

Implications for practice

the PQI intervention evaluated here offers an effective way to improve the quality of health services in low-resource settings and should continue to be scaled up in Malawi.