Meta-analysis of operative mortality and complications in patients from minority ethnic groups.

BACKGROUND: Insight into the effects of ethnic disparities on patients' perioperative safety is necessary for the development of tailored improvement strategies. The aim of this study was to review the literature on safety differences between patients from minority ethnic groups and those from the ethnic majority undergoing surgery. METHODS: PubMed, CINAHL, the Cochrane Library and Embase were searched using predefined inclusion criteria for available studies from January 1990 to January 2013. After quality assessment, the study data were organized on the basis of outcome, statistical significance and the direction of the observed effects. Relative risks for mortality were calculated. RESULTS: After screening 3105 studies, 26 studies were identified. Nine of these 26 studies showed statistically significant higher mortality rates for patients from minority ethnic groups. Meta-analysis demonstrated a greater risk of mortality for these patients compared with patients from the Caucasian majority in studies performed both in North America (risk ratio 1·22, 95 per cent confidence interval 1·05 to 1·42) and outside (risk ratio 2·25, 1·40 to 3·62). For patients from minority groups, the length of hospital or intensive care unit stay was significantly longer in five studies, and complication rates were significantly higher in ten. Methods used to identify patient ethnicity were not described in 14 studies. CONCLUSION: Patients from minority ethnic groups, in North America and elsewhere, have an increased risk of perioperative death and complications. More insight is needed into the causes of ethnic disparities to pursue safer perioperative care for patients of minority ethnicity.

Experiences with anaerobic treatment of fat-containing food waste liquids: two full scale studies with a novel anaerobic flotation reactor.

Fat-containing food waste can be effectively treated in a new type of reactor, the so-called BIOPAQ-Anaerobic Flotation Reactor or BIOPAQ(®) anaerobic flotation reactor (AFR). In the reactor a flotation unit is integrated to retain the sludge. In this study results from two plants with a 430 and 511 m(3)-AFR, respectively, are presented. In one reactor, which is fed with water originating from different food liquid streams, over 99% of fat and oils were removed. Over 90% of the chemical oxygen demand (COD) was removed. When the last solids were removed from the effluent with a tilted plate settler, 98% COD removal was attained. The effluent concentrations of extractable hydrolysed and non-hydrolysed fats were less than 40 mg/l. Apparently the variations in the liquid streams deriving from the tank cleaning activities did not disturb the system. Only extremely high concentrations of fats could disturb the system, but the inhibition was reversible. In the reactor treating water from an ice-cream factory, which contained fats up to approximately 50% of influent COD, a COD removal efficiency of 90% was achieved. At volumetric loading rates varying from 1 to 8 kg COD/m(3)/d, biogas was produced at an average specific gas production of 0.69 m(3)/kg COD-removed.

Measuring a caring culture in hospitals: a systematic review of instruments.

OBJECTIVE: To identify instruments or components of instruments that aim to measure aspects of a caring culture-shared beliefs, norms and values that direct professionals and managers to act caring in hospitals, and to evaluate their psychometric properties. DESIGN: Systematic review. DATA SOURCES: PubMed, CINAHL, EMBASE, PsychInfo, Web of Science and the International bibliography of the Social Sciences. STUDY SELECTION: Peer-reviewed articles describing (components of) instruments measuring aspects of a caring culture in a hospital setting. Studies had to report psychometric data regarding the reliability or validity of the instrument. Potentially useful instruments that were identified after the title and abstract scan were assessed on relevance by an expert panel (n=12) using the RAND-modified Delphi procedure. RESULTS: Of the 6399 references identified, 75 were examined in detail. 7 studies each covering a unique instrument met our inclusion criteria. On average, 24% of the instrument's items were considered relevant for measuring aspects of the hospital's caring culture. Studies showed moderate-to-high validity and reliability scores. Validity was addressed for 6 of the 7 instruments. Face, content (90%) and construct (60%) validity were the most frequently reported psychometric properties described. One study (14%) reported discriminant validity of the instrument. Reliability data were available for all of the instruments. Internal consistency was the most frequently reported psychometric property for the instruments and demonstrated by: a Cronbach's α coefficient (80%), subscale intercorrelations (60%), and item-total correlations (40%). CONCLUSIONS: The ultimate standard for measuring a caring culture in hospitals does not exist. Existing instruments provide partial coverage and lack information on discriminant validity, responsiveness and feasibility. Characteristics of the instruments included in this review could provide useful input for the design of a reliable and valid instrument for measuring a caring culture in hospitals.

Distribution of sulfate-reducing and methanogenic bacteria in anaerobic aggregates determined by microsensor and molecular analyses.

Using molecular techniques and microsensors for H(2)S and CH(4), we studied the population structure of and the activity distribution in anaerobic aggregates. The aggregates originated from three different types of reactors: a methanogenic reactor, a methanogenic-sulfidogenic reactor, and a sulfidogenic reactor. Microsensor measurements in methanogenic-sulfidogenic aggregates revealed that the activity of sulfate-reducing bacteria (2 to 3 mmol of S(2-) m(-3) s(-1) or 2 x 10(-9) mmol s(-1) per aggregate) was located in a surface layer of 50 to 100 microm thick. The sulfidogenic aggregates contained a wider sulfate-reducing zone (the first 200 to 300 microm from the aggregate surface) with a higher activity (1 to 6 mmol of S(2-) m(-3) s(-1) or 7 x 10(-9) mol s(-1) per aggregate). The methanogenic aggregates did not show significant sulfate-reducing activity. Methanogenic activity in the methanogenic-sulfidogenic aggregates (1 to 2 mmol of CH(4) m(-3) s(-1) or 10(-9) mmol s(-1) per aggregate) and the methanogenic aggregates (2 to 4 mmol of CH(4) m(-3) s(-1) or 5 x 10(-9) mmol s(-1) per aggregate) was located more inward, starting at ca. 100 microm from the aggregate surface. The methanogenic activity was not affected by 10 mM sulfate during a 1-day incubation. The sulfidogenic and methanogenic activities were independent of the type of electron donor (acetate, propionate, ethanol, or H(2)), but the substrates were metabolized in different zones. The localization of the populations corresponded to the microsensor data. A distinct layered structure was found in the methanogenic-sulfidogenic aggregates, with sulfate-reducing bacteria in the outer 50 to 100 microm, methanogens in the inner part, and Eubacteria spp. (partly syntrophic bacteria) filling the gap between sulfate-reducing and methanogenic bacteria. In methanogenic aggregates, few sulfate-reducing bacteria were detected, while methanogens were found in the core. In the sulfidogenic aggregates, sulfate-reducing bacteria were present in the outer 300 microm, and methanogens were distributed over the inner part in clusters with syntrophic bacteria.

Experimental and theoretical investigations on the validity of the geometrical optics model for calculating the stability of optical traps.

We have developed a computer program based on the geometrical optics approach proposed by Roosen to calculate the forces on dielectric spheres in focused laser beams. We have explicitly taken into account the polarization of the laser light and thd divergence of the laser beam. The model can be used to evaluate the stability of optical traps in a variety of different optical configurations. Our calculations explain the experimental observation by Ashkin that a stable single-beam optical trap, without the help of the gravitation force, can be obtained with a strongly divergent laser beam. Our calculations also predict a different trap stability in the directions orthogonal and parallel to the polarization direction of the incident light. Different experimental methods were used to test the predictions of the model for the gravity trap. A new method for measuring the radiation force along the beam axis in both the stable and instable regions is presented. Measurements of the radiation force on polystyrene spheres with diameters of 7.5 and 32 microns in a TEM00-mode laser beam showed a good qualitative correlation with the predictions and a slight quantitative difference. The validity of the geometrical approximations involved in the model will be discussed for spheres of different sizes and refractive indices.