Selectivity in separation using π electron-rich stationary phases for the comprehensive two-dimensional analysis of cafe espresso

The multidimensional high-performance liquid chromatography separations of the complex sample matrix found in café espresso coffee were completed on the propyl phenyl and butyl phenyl columns that contain 3 and 4 carbon atoms in the spacer chain, respectively. Phenyl type stationary phases are able to undergo unique π–π interactions with aromatic compounds. Previous works have found that there are differences in retention characteristics between these chain lengths and this was explored further here. It was found that when analysing the separations by quadrants, using a geometric approach to factor analysis and by measuring the normalised mean radius, subtle differences in the separations were observed and the butyl phenyl phase was more selective for the high to medium polarity species. However, there was very little difference in separation behaviour for the hydrophobic components within the coffee sample. Overall, the analysis of the entire separation showed very little difference.

A boarding school outbreak of pertussis in adolescents : value of laboratory diagnostic methods

Culture for Bordetella pertussis (B. pertussis) is the traditional gold standard for laboratory diagnosis of pertussis but is insensitive, especially later in the course of illness and in vaccinated persons. Interpretation of serology is limited by the lack of an appropriate reference standard. An outbreak of pertussis in a crowded boarding-school dormitory allowed evaluation of laboratory correlates of infection. Questionnaires, serum samples and throat swabs were collected from members of the exposed group. Serum samples from unexposed controls of a similar age group were used for comparison. B. pertussis PCR was performed on throat swabs, and sera were tested for IgA antibodies against whole-cell (WC) B. pertussis antigen and IgG antibodies to pertussis toxin (PT). The Centers for Disease Control and Prevention definition for pertussis was used to define clinical cases. We evaluated the use of a previously published cut-off for PT IgG of 125 EIA units (EU)/ml. Completed questionnaires were obtained from 115 students, of whom 85 (74%) reported coughing symptoms, including 32 (28%) who met the clinical case definition for pertussis. B. pertussis was detected by PCR in 17 (15%) and WC IgA in 22 (19%) students; neither correlated with symptoms, but dormitory of residence strongly predicted PCR status. The mean PT IgG geometric mean concentration, in this situation of high pertussis exposure, correlated with severity of symptoms and was significantly higher in both symptomatic and asymptomatic children exposed during the outbreak (P<0·001) than in control children. A cut-off for PT IgG of 125 EU/ml was too high in an outbreak situation to be sensitive enough to identify pertussis cases. A case of pertussis in a crowded boarding-school dormitory resulted rapidly in an outbreak. Serology and PCR were useful in identifying the outbreak and commencing disease control measures. The use of serology has mostly been evaluated in community serosurveys, where it is not possible to determine if immunity reflects vaccination, asymptomatic disease or symptomatic disease. This outbreak gave us the opportunity to evaluate the value of serology and PCR in the presence of confirmed exposure to pertussis.

Habitat suitability for marine fishes using presence-only modelling and multibeam sonar

Improved access to multibeam sonar and underwater video technology is enabling scientists to use spatially-explicit, predictive modelling to improve our understanding of marine ecosystems. With the growing number of modelling approaches available, knowledge of the relative performance of different models in the marine environment is required. Habitat suitability of 5 demersal fish taxa in Discovery Bay, south-east Australia, were modelled using 10 presence-only algorithms: BIOCLIM, DOMAIN, ENFA (distance geometric mean [GM], distance harmonic mean [HM], median [M], area-adjusted median [Ma], median + extremum [Me], area-adjusted median + extremum [Mae] and minimum distance [Min]), and MAXENT. Model performance was assessed using kappa and area under curve (AUC) of the receiver operator characteristic. The influence of spatial range (area of occupancy) and environmental niches (marginality and tolerance) on modelling performance were also tested. MAXENT generally performed best, followed by ENFA-GM and -HM, DOMAIN, BIOCLIM, ENFA-M, -Min, -Ma, -Mae and -Me algorithms. Fish with clearly definable niches (i.e. high marginality) were most accurately modelled. Generally, Euclidean distance to nearest reef, HSI-b (backscatter), rugosity and maximum curvature were the most important variables in determining suitable habitat for the 5 demersal fish taxa investigated. This comparative study encourages ongoing use of presence-only approaches, particularly MAXENT, in modelling suitable habitat for demersal marine fishes.

Is this D vitamin to worry about? Vitamin D insufficiency in an inpatient sample

Objective: The aim of the present study was to investigate the relationship between reduced serum vitamin D levels and psychiatric illness.

Method: This study was an audit of serum 25-hydroxyvitamin D (25-OHD) levels measured routinely in a sample of 53 inpatients in a private psychiatric clinic. These levels were compared with those of controls without psychiatric illness.

Results: The median levels of serum 25-OHD were 43.0 nmol L⁻¹ (range 20–102 nmol L⁻¹) in the patient population, 46.0 nmol L⁻¹ (range 20–102 nmol L⁻¹) in female patients (n =33) and 41.5 nmol L⁻¹ (range 22–97 nmol L⁻¹) in male patients (n =20). The proportion of vitamin D insufficiency (serum 25-OHD ≤50 nmol L⁻¹) in this patient population was 58%. Furthermore, 11% had moderate deficiency (serum 25-OHD ≤25 nmol L⁻¹). There was a 29% difference between mean levels in the patient population and control sample (geometric mean age- and season-adjusted levels: 46.4 nmol L⁻¹ (95% confidence interval (CI) =38.6–54.9 nmol L⁻¹) vs 65.3 nmol L⁻¹ (95%CI =63.2–67.4 nmol L⁻¹), p <0.001).

Conclusion: Low levels of serum 25-OHD were found in this patient population. These data add to the literature suggesting an association between vitamin D insufficiency and psychiatric illness, and suggest that routine monitoring of vitamin D levels may be of benefit given the high yield of clinically relevant findings.

Leptin in depressed women : Cross-sectional and longitudinal data from an epidemiologic study

Background There is conflicting evidence regarding levels of leptin in depression. In this study we aimed to investigate the relationship between serum leptin level and depression in a community sample of women using both cross-sectional and longitudinal data.

Methods From among 510 women aged 20–78 yr, 83 were identified with a lifetime history of major depressive disorder or dysthymia, ascertained using the Structured Clinical Interview for DSM-IV-TR Research Version, Non-patient edition (SCID-I/NP). Serum leptin levels were measured by radioimmunoassay. Medication use and lifestyle were self-reported and body mass index (BMI) determined from measures of height and weight.

Results Using multiple linear regression, serum leptin levels were greater among women with a lifetime history of depression compared to women without any history of depression, independent of BMI. Adjusted geometric mean values of serum leptin were 16.37 (95%CI 14.70–18.23) ng/mL for depressed and 14.46 (95%CI 13.79–15.16) ng/mL for non-depressed women (P = 0.039). The hazard ratio (HR) for a de novo depressive disorder over five years increased 2.56-fold for each standard deviation increase in log-transformed serum leptin among non-smokers and this was not explained by differences in BMI, medications or other lifestyle factors (HR = 2.56, 95%CI 1.52-4.30). No association was observed for smokers.

Limitations There is potential for unrecognised confounding, recall bias and transient changes in body composition.

Conclusion Women with a lifetime history of depression have elevated levels of serum leptin, and elevated serum leptin predicts subsequent development of a depressive disorder.

Parent initiated prednisolone for acute asthma in children of school age : randomised controlled crossover trial

Objective To evaluate the efficacy of a short course of parent initiated oral prednisolone for acute asthma in children of school age.

Design Double blind, randomised, placebo controlled, crossover trial in which episodes of asthma, rather than participants, were randomised to treatment.

Setting The Barwon region of Victoria, Australia.

Participants Children aged 5-12 years with a history of recurrent episodes of acute asthma.

Intervention A short course of parent initiated treatment with prednisolone (1 mg/kg a day) or placebo.

Main outcome measures The primary outcome measure was the mean daytime symptom score over seven days. Secondary outcome measures were mean night time symptom score over seven days, use of health resources, and school absenteeism.

Results 230 children were enrolled in the study. Over a three year period, 131 (57%) of the participants contributed a total of 308 episodes of asthma that required parent initiated treatment: 155 episodes were treated with parent initiated prednisolone and 153 with placebo. The mean daytime symptom score was 15% lower in episodes treated with prednisolone than in those treated with placebo (geometric mean ratio 0.85, 95% CI 0.74 to 0.98; P=0.023). Treatment with prednisolone was also associated with a 16% reduction in the night time symptom score (geometric mean ratio 0.84, 95% CI 0.70 to 1.00; P=0.050), a reduced risk of health resource use (odds ratio 0.54, 95% CI 0.34 to 0.86; P=0.010), and reduced school absenteeism (mean difference −0.4 days, 95% CI −0.8 to 0.0 days; P=0.045).

Conclusion A short course of oral prednisolone initiated by parents when their child experiences an episode of acute asthma may reduce asthma symptoms, health resource use, and school absenteeism. However, the modest benefits of this strategy must be balanced against potential side effects of repeated short courses of an oral corticosteroid.

Effect of moisture content on the physical properties of fibered flaxseed

The physical properties of fibered flaxseed were investigated within moisture content varying from 6.21 to 16.29%. The length, width, thickness and geometric mean diameter increased from 4.20 to 4.44mm, 1.99 to 2.13mm, 0.91 to 0.95mm, and 1.95 to 2.06mm, respectively in the moisture content range. One thousand seed weight increased linearly from 4.22 to 4.62g. The bulk density decreased from 726.783 to 611.872kg/m3, while the true density increased from 1165.265 to 1289.341kg/m3 in the moisture content range. The porosity values of flaxseed increased linearly from 37.67 to 52.54%. The highest static coefficient of friction was found on the plywood surface, while the lowest on the stainless steel surface. The static coefficient of friction increased from 0.467 to 0.972, 0.442 to 0.864, 0.492 to 0.927, and 0.490 to 0.845 for plywood, stainless steel, aluminum sheet and galvanized iron, respectively. The angle of repose increased linearly from 25.7° to 33.8° in the moisture content range. The results are necessary for design of equipment to handling, transportation, processing, and the storage of flaxseed.

Enhanced recovery after surgery program for elective adbominal surgery at three Victorian hospitals

The aim of this study was to evaluate the anaesthesia care of an enhanced recovery after surgery (ERAS) program for patients having abdominal surgical in Victorian hospitals. The man outcome measure was the number of ERAS items implemented following introduction of the ERAS program. Secondary endpoints included process of care measures, outcomes and hospital stay. We used a before-and-after design; the control group was a prospective cohort (n=154) representing pre-existing practice for elective abdominal surgical patients from July 2009. The introduction of a comprehensive ERAS program took place over two months and included the education of surgeons, anaesthetists, nurses and allied health professionals. A post-implementation cohort (n=169) was enrolled in early 2010. From a total of 14 ERAS-recommended items, there were significantly more implemented in the post-ERAS period, median 8 (interquartile range of 7 to 9) vs 9 (8 to 10), P <0.0001. There were, however, persistent low rates of intravenous fluid restriction (25%) and early removal of urinary catheter (31%) in the post-ERAS period. ERAS patients had less pain and faster recovery parameters, and this was associated with a reduced hospital stay, geometric mean (SD) 5.7 (2.5) vs 7.4 (2.1) days, P=0.006. We found that perioperative anaesthesia practices can be readily modified to incorporate an enhanced recovery program in Victorian hospitals.

Enhanced Recovery After Surgery program for elective abdominal surgery at three Victorian hospitals

The aim of this study was to evaluate the anaesthesia care of an enhanced recovery after surgery (ERAS) program for patients having abdominal surgical in Victorian hospitals. The main outcome measure was the number of ERAS items implemented following introduction of the ERAS program. Secondary endpoints included process of care measures, outcomes and hospital stay. We used a before-and-after design; the control group was a prospective cohort (n=154) representing pre-existing practice for elective abdominal surgical patients from July 2009. The introduction of a comprehensive ERAS program took place over two months and included the education of surgeons, anaesthetists, nurses and allied health professionals. A post-implementation cohort (n=169) was enrolled in early 2010. From a total of 14 ERAS-recommended items, there were significantly more implemented in the post-ERAS period, median 8 (interquartile range 7 to 9) vs 9 (8 to 10), P <0.0001. There were, however, persistent low rates of intravenous fluid restriction (25%) and early removal of urinary catheter (31%) in the post-ERAS period. ERAS patients had less pain and faster recovery parameters, and this was associated with a reduced hospital stay, geometric mean (SD) 5.7 (2.5) vs 7.4 (2.1) days, P=0.006. We found that perioperative anaesthesia practices can be readily modified to incorporate an enhanced recovery program in Victorian hospitals.

Wettability investigation of UV/oand acid functionalized MWCNT and MWCNT/PMMA nanocomposites by contact angle measurement

The dispersion state of individual MWCNT in the polymer matrix influences the mechanical, thermal, and electrical properties of the resulting composite. One method of obtaining a good dispersion state of MWCNT in a polymer matrix is to functionalize the surface of MWCNT using various treatments to enhance the surface energy and increase the dispersibility of MWCNT. In this study, wettability and surface energy of UV/Oand acid-treated multiwall carbon nanotubes (MWCNTs) and its polymethyl methacrylate (PMMA) polymer nanocomposites were measured using contact angle analysis in various solvent media. Contact angle analysis was based on ethylene glycol-water-glycerol probe liquid set and data was further fitted into geometric mean (Fowkes), van Oss-Chaudhury-Good (GvOC), and Chang-Qing-Chen (CQC) models to determine both nonpolar and acid base surface energy components. Analysis was conducted on MWCNT thin films subjected to different levels of UV/Oand acid treatments as well as their resulting MWCNT/PMMA nanocomposites. Contact angle analysis of thin films and nanocomposites revealed that the total surface energy of all samples was well fitted with each other. In addition, CQC model was able to determine the surface nature and polarity of MWCNT and its nanocomposites. Results indicated that the wettability changes in the thin film and its nanocomposites are due to the change in surface chemistry. Finally, electrical properties of nanocomposites were measured to investigate the effect of surface functionality (acid or basic) on the MWCNT surfaces.

Optimal fire histories for biodiversity conservation

Fire is used as a management tool for biodiversity conservation worldwide. A common objective is to avoid population extinctions due to inappropriate fire regimes. However, in many ecosystems, it is unclear what mix of fire histories will achieve this goal. We determined the optimal fire history of a given area for biological conservation with a method that links tools from 3 fields of research: species distribution modeling, composite indices of biodiversity, and decision science. We based our case study on extensive field surveys of birds, reptiles, and mammals in fire-prone semi-arid Australia. First, we developed statistical models of species' responses to fire history. Second, we determined the optimal allocation of successional states in a given area, based on the geometric mean of species relative abundance. Finally, we showed how conservation targets based on this index can be incorporated into a decision-making framework for fire management. Pyrodiversity per se did not necessarily promote vertebrate biodiversity. Maximizing pyrodiversity by having an even allocation of successional states did not maximize the geometric mean abundance of bird species. Older vegetation was disproportionately important for the conservation of birds, reptiles, and small mammals. Because our method defines fire management objectives based on the habitat requirements of multiple species in the community, it could be used widely to maximize biodiversity in fire-prone ecosystems. © 2014 Society for Conservation Biology.

Linear optimization for ecological indices based on aggregation functions

We consider an optimization problem in ecology where our objective is to maximize biodiversity with respect to different land-use allocations. As it turns out, the main problem can be framed as learning the weights of a weighted arithmetic mean where the objective is the geometric mean of its outputs. We propose methods for approximating solutions to this and similar problems, which are non-linear by nature, using linear and bilevel techniques.

Estimating mean exposures from censored data: exposure to benzene in the Australian petroleum industry

A retrospective assessment of exposure to benzene was carried out for a nested case control study of lympho-haematopoietic cancers, including leukaemia, in the Australian petroleum industry. Each job or task in the industry was assigned a Base Estimate (BE) of exposure derived from task-based personal exposure assessments carried out by the company occupational hygienists. The BEs corresponded to the estimated arithmetic mean exposure to benzene for each job or task and were used in a deterministic algorithm to estimate the exposure of subjects in the study. Nearly all of the data sets underlying the BEs were found to contain some values below the limit of detection (LOD) of the sampling and analytical methods and some were very heavily censored; up to 95% of the data were below the LOD in some data sets. It was necessary, therefore, to use a method of calculating the arithmetic mean exposures that took into account the censored data. Three different methods were employed in an attempt to select the most appropriate method for the particular data in the study. A common method is to replace the missing (censored) values with half the detection limit. This method has been recommended for data sets where much of the data are below the limit of detection or where the data are highly skewed; with a geometric standard deviation of 3 or more. Another method, involving replacing the censored data with the limit of detection divided by the square root of 2, has been recommended when relatively few data are below the detection limit or where data are not highly skewed. A third method that was examined is Cohen's method. This involves mathematical extrapolation of the left-hand tail of the distribution, based on the distribution of the uncensored data, and calculation of the maximum likelihood estimate of the arithmetic mean. When these three methods were applied to the data in this study it was found that the first two simple methods give similar results in most cases. Cohen's method on the other hand, gave results that were generally, but not always, higher than simpler methods and in some cases gave extremely high and even implausible estimates of the mean. It appears that if the data deviate substantially from a simple log-normal distribution, particularly if high outliers are present, then Cohen's method produces erratic and unreliable estimates. After examining these results, and both the distributions and proportions of censored data, it was decided that the half limit of detection method was most suitable in this particular study.

Bone geometry in response to long-term tennis playing and its relationship with muscle volume : a quantitative magnetic resonance imaging study in tennis players

The benefit of impact-loading activity for bone strength depends on whether the additional bone mineral content (BMC) accrued at loaded sites is due to an increased bone size, volumetric bone mineral density (vBMD) or both. Using magnetic resonance imaging (MRI) and dual energy X-ray absorptiometry (DXA), the aim of this study was to characterize the geometric changes of the dominant radius in response to long-term tennis playing and to assess the influence of muscle forces on bone tissue by investigating the muscle–bone relationship. Twenty tennis players (10 men and 10 women, mean age: 23.1 ± 4.7 years, with 14.3 ± 3.4 years of playing) were recruited. The total bone volume, cortical volume, sub-cortical volume and muscle volume were measured at both distal radii by MRI. BMC was assessed by DXA and was divided by the total bone volume to derive vBMD. Grip strength was evaluated with a dynamometer. Significant side-to-side differences (P < 0.0001) were found in muscle volume (+9.7%), grip strength (+13.3%), BMC (+13.5%), total bone volume (+10.3%) and sub-cortical volume (+20.6%), but not in cortical volume (+2.6%, ns). The asymmetry in total bone volume explained 75% of the variance in BMC asymmetry (P < 0.0001). vBMD was slightly higher on the dominant side (+3.3%, P < 0.05). Grip strength and muscle volume correlated with all bone variables (except vBMD) on both sides (r = 0.48–0.86, P < 0.05–0.0001) but the asymmetries in muscle parameters did not correlate with those in bone parameters. After adjustment for muscle volume or grip strength, BMC was still greater on the dominant side. This study showed that the greater BMC induced by long-term tennis playing at the dominant radius was associated to a marked increase in bone size and a slight improvement in volumetric BMD, thereby improving bone strength. In addition to the muscle contractions, other mechanical stimuli seemed to exert a direct effect on bone tissue, contributing to the specific bone response to tennis playing.

Skeletal benefits after long-term retirement in former elite female gymnasts

Bone strength benefits after long-term retirement from elite gymnastics in terms of bone geometry and volumetric BMD were studied by comparing retired female gymnasts to moderately active age-matched women. In a cross-sectional study, 30 retired female gymnasts were compared with 30 age-matched moderately active controls. Bone geometric and densitometric parameters were measured by pQCT at the distal epiphyses and shafts of the tibia, femur, radius, and humerus. Muscle cross-sectional areas were assessed from the shaft scans. Independent t-tests were conducted on bone and muscle variables to detect differences between the two groups. The gymnasts had retired for a mean of 6.1 ± 0.4 yr and were engaged in ≤2 h of exercise per week since retirement. At the radial and humeral shafts, cortical cross-sectional area (CSA), total CSA, BMC, and strength strain index (SSIpol) were significantly greater (13–38%, p ≤ 0.01) in the retired gymnasts; likewise, BMC and total CSA were significantly greater at the distal radius (22–25%, p ≤ 0.0001). In the lower limbs, total CSA and BMC at the femur and tibia shaft were greater by 8–11%, and trabecular BMD and BMC were only greater at the tibia (7–8%). Muscle CSA at the forearm and upper arm was greater by 15–17.6% (p ≤ 0.001) but was not different at the upper and lower leg. Past gymnastics training is associated with greater bone mass and bone size in women 6 yr after retirement. Skeletal benefits were site specific, with greater geometric adaptations (greater bone size) in the upper compared with the lower limbs.