94 research outputs found
The Morphology of Black Tea Cream
The colloidal precipitate known as tea cream, which separates when a hot aqueous infusion of black tea is cooled, is investigated by electron microscopic (EM) techniques of shadowing, sectioning, freeze-etching and scanning and also by optical microscopy. These indicate tea cream to be an association colloid, the morphology of which depends on overall solids concentration. Dilute infusions (0.1% w/w) produce macromolecular aggregates of about 50 run, but at higher tea solids concentrations secondary aggregation of the initial particles results in ill-defined clusters of approximately 1 um in diameter. At 5% w/w, clear , spherical liquid droplets, typically 1-2 um in diameter are observed . Increasing concentration to 40% w/w causes an increase in size of the individual colloidal droplets and an increase in the phase volume of this disperse phase. The colloidal phase contains 55 - 65% solids by weight, the total solids content appearing to be independent of overall composition of the solutions from which it is formed. The colloid may be separated from cooled tea infusions by centrifugation but individual particles display strong resistance to coalescence. At high tea cream phase volumes phase inversion can occur and dispersions of the dilute phase in a continuous cream phase are then observed
Accelerated Model Checking of Parametric Markov Chains
Parametric Markov chains occur quite naturally in various applications: they
can be used for a conservative analysis of probabilistic systems (no matter how
the parameter is chosen, the system works to specification); they can be used
to find optimal settings for a parameter; they can be used to visualise the
influence of system parameters; and they can be used to make it easy to adjust
the analysis for the case that parameters change. Unfortunately, these
advancements come at a cost: parametric model checking is---or rather
was---often slow. To make the analysis of parametric Markov models scale, we
need three ingredients: clever algorithms, the right data structure, and good
engineering. Clever algorithms are often the main (or sole) selling point; and
we face the trouble that this paper focuses on -- the latter ingredients to
efficient model checking. Consequently, our easiest claim to fame is in the
speed-up we have often realised when comparing to the state of the art
Evaluation and monitoring of terrestrial and aquatic insect biodiversity in forested and cleared watersheds at Camp Atterbury, Indiana.
Executive Summary
Camp Atterbury is a 33,132 ha military installation near Edinburgh, Indiana. Construction of a 80 ha (4,550
ha with safety fan) Multi-Purpose Training Range (MPTR) began in 1998, and supports training for military vehicles
and dismounted infantry, with a variety of stationary and moving targets. This study provides a baseline for long term
monitoring and evaluation of natural communities to assess the impacts of construction of, and training in, the MPTR.
We assessed both aquatic macroinvertebrate and terrestrial insect community diversity, abundance, and
richness and similarity at a series of study plots using quantifiable, repeatable and replicated methods. These data
provide baseline data facilitating long-term monitoring and assessment as a measure of ecosystem health, and allow
evaluation of relationships between community composition and habitat metrics.
Methods
Eight terrestrial study sites, each comprised of a 30 m square plot, were randomly selected, with four of
these placed in the cleared portions of the MPTR and four placed in adjacent upland forest. We used several
sampling methods, with focus on three groups of taxa (all insect taxa, ants, and leafhoppers and kin) and compared
the efficacy of both the methods and the groups as monitoring tools. Sampling methods included: 1) a Malaise trap
(mesh tent-like device that captures flying insects) at each site; 2) four sweep sample transects at each site; 3) four
leaf litter samples from each site, with invertebrates extracted using the Winkler method; and 4) Nine pitfall traps at
each site. Samples were collect during Summer and Fall study periods, and this report gives results from the
Summer sample period. Several habitat parameters were recorded, including a vegetation index, canopy cover,
ground cover, and leaf litter depth. Dominant plant taxa were collected, and data loggers recorded soil and air
temperature during the study.
We sampled aquatic macroinvertebrates at three stream sites draining the MPTR. Invertebrates were
collected in replicate samples with a dipnet and these were sorted and subsampled in the laboratory. Canopy cover
and basic water chemistry data were collected, and data loggers recorded changes in terrestrial and aquatic
temperature. An index of biotic integrity and taxon richness were used to evaluate the aquatic communities.
Results and Discussion
At least 409 taxa and 3776 specimens were collected at terrestrial sample sites during the Summer sampling
period. In general, there were some differences among sites, among sampling methods, and among treatments
(cleared MPTR versus forested) when we examined taxon richness and species diversity, but these differences could
not always be fully resolved. While taxon richness and species diversity differed among treatments, and, in general,
plots in the two treatments harbored different insect communities. Species accumulation curves and various
estimators of taxon richness were used to evaluate the four sampling methods and the three groups of taxa (all taxa,
ants, leafhoppers). Based on the performance of the different taxa (all, ants, leafhoppers) compared across the
different methods (malaise sampling, Winkler extracted leaf litter samples, pitfall traps, and sweep samples), the
single most effective taxon for monitoring was found to be the ants (Formicidae), and the single best method for
monitoring was found to be pitfall trapping.
We collected 818 specimens, primarily aquatic macroinvertebrates, from the three stream sites during
Summer sampling. All three streams were dry during the fall sample period, and thus no aquatic macroinvertebrates
were collected. Using Hilsenhoff’s (1988) family-level index of biotic integrity, water quality was classified as “good”
at one site, and “fair” at the other two, although taxon richness was lowest at the site classified as good. In addition
to invertebrates, numerous salamanders (Eurycea cirrigera, the Two-lined Salamander) were observed in the
streams.
3
For aquatic invertebrates, we found that the small upstream portions that directly drained the MPTR only
held water seasonally, and thus were not effective sites for monitoring of stream macroinvertebrates. There was
insufficient separation between MPTR-influenced stream sites and control sites, and a lack of replication (few
streams flowing away from the MPTR) precluded robust statistical analysis of the data we did obtain. The community
of aquatic macroinvertebrates collected during this study appeared similar to the communities reported by Robinson
(2004) elsewhere at Camp Atterbury in larger streams, and includes taxa typical of rocky bottom Midwestern forest
streams. Fish were largely absent due to the intermittent nature of the streams. Salamanders were abundant in the
streams, and because they are top predators in this seasonal habitat, they may be suitable subjects for studies of
potential bioaccumulation of toxins.
This study provides a snapshot of insect biodiversity at a point in time, thus providing baseline for any
possible future monitoring of insect biodiversity. Sampling methods and analyses developed in this study could
easily be implemented at a wide variety of other military installations to facilitate inventory and/or monitoring of insect
biodiversity.Ope
Proteomic Biomarkers for Acute Interstitial Lung Disease in Gefitinib-Treated Japanese Lung Cancer Patients
Interstitial lung disease (ILD) events have been reported in Japanese non-small-cell lung cancer (NSCLC) patients receiving EGFR tyrosine kinase inhibitors. We investigated proteomic biomarkers for mechanistic insights and improved prediction of ILD. Blood plasma was collected from 43 gefitinib-treated NSCLC patients developing acute ILD (confirmed by blinded diagnostic review) and 123 randomly selected controls in a nested case-control study within a pharmacoepidemiological cohort study in Japan. We generated ∼7 million tandem mass spectrometry (MS/MS) measurements with extensive quality control and validation, producing one of the largest proteomic lung cancer datasets to date, incorporating rigorous study design, phenotype definition, and evaluation of sample processing. After alignment, scaling, and measurement batch adjustment, we identified 41 peptide peaks representing 29 proteins best predicting ILD. Multivariate peptide, protein, and pathway modeling achieved ILD prediction comparable to previously identified clinical variables; combining the two provided some improvement. The acute phase response pathway was strongly represented (17 of 29 proteins, p = 1.0×10−25), suggesting a key role with potential utility as a marker for increased risk of acute ILD events. Validation by Western blotting showed correlation for identified proteins, confirming that robust results can be generated from an MS/MS platform implementing strict quality control
Are women with history of pre-eclampsia starting a new pregnancy in good nutritional status in South Africa and Zimbabwe?
Background
Maternal nutritional status before and during pregnancy is an important contributor to pregnancy outcomes and early child health. The aim of this study was to describe the preconceptional nutritional status and dietary intake during pregnancy in high-risk women from South Africa and Zimbabwe.
Methods
This is a prospective observational study, nested to the CAP trial. Anthropometric measurements before and during pregnancy and dietary intake using 24-h recall during pregnancy were assessed. The Intake Distribution Estimation software (PC-SIDE) was used to evaluate nutrient intake adequacy taking the Estimated Average Requirement (EAR) as a cut-off point.
Results
Three hundred twelve women who had pre-eclampsia in their last pregnancy and delivered in hospitals from South Africa and Zimbabwe were assessed. 73.7 and 60.2% women in South Africa and Zimbabwe, respectively started their pregnancy with BMI above normal (BMI ≥ 25) whereas the prevalence of underweight was virtually non-existent. The majority of women had inadequate intakes of micronutrients. Considering food and beverage intake only, none of the micronutrients measured achieved the estimated average requirement. Around 60% of pregnant women reported taking folic acid or iron supplements in South Africa, but almost none did so in Zimbabwe.
Conclusion
We found a high prevalence of overweight and obesity and high micronutrient intake inadequacy in pregnant women who had the previous pregnancy complicated with pre-eclampsia. The obesity figures and micronutrient inadequacy are issues of concern that need to be addressed. Pregnant women have regular contacts with the health system; these opportunities could be used to improve diet and nutrition.
Trial registration
PACTR201105000267371
. Registered 06 December 2010
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Solvent effects on phototriggered conformational changes in an azobenzene-functionalized poly( p-phenylene vinylene)
Poly(2-hexyloxy-5-((10-(4-(phenylazo)phenoxy)decyl)oxy)-1,4-phenylene vinylene) (HPA-10-PPV) is an azobenzene-functionalized poly(
p-phenylene vinylene) derivative that previously has been shown to undergo changes in the position and shape of its fluorescence spectrum in response to
trans
→
cis-azobenzene photoisomerization. This effect was initially observed in a binary dichloromethane-methanol solution and was attributed to a phototriggered expansion of polymer coil dimensions. In this report we explore the mechanism by which azobenzene isomerization induces this conformational change and the solvent properties that govern the magnitude of the change. Phototriggered fluorescence shifts are observed in mixtures of dichloromethane and each of 12 cosolvents, 7 protic and 5 aprotic. The shifts are largest in protic solvents but do not correlate with any single solvent parameter or combination of parameters. Smaller shifts are observed in mixtures with aprotic cosolvents, and the magnitude of these shifts correlates with solvent polarity/polarizability. The conformational changes responsible for the fluorescence shifts are attributed to a change in polymer–solvent interactions induced by the difference between properties of the
trans- and
cis-azobenzene isomers. Isomerization to the more polar
cis-azobenzene promotes an increase in polymer–solvent interactions. These results suggest a means by which the magnitude of phototriggered fluorescence changes could be increased in future derivatives
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