Processing of chemical solution-deposited BaTiO<Subscript>3</Subscript>-based thin films on Ni foils

BaTiO₃ films on base metal foils are of interest for capacitor applications, but the processing requires reducing atmospheres that influence the film defect chemistry and density. In this study, powders dried from barium titanate solutions and barium titanate films were studied by X-ray diffraction, differential scanning calorimetry, thermal gravimetric analysis, infrared spectroscopy, and spectroscopic ellipsometry at various points in the processing. It was found that atmospheres designed to minimize Ni oxidation delay decomposition of organics, leading to retained carbonate phases. Thus, crystallization of the barium titanate occurs via decomposition of a barium carbonate phase. Retained organics that are present during high temperature processing can cause porosity in the films. On annealing at 1000 °C, there is slightly increase in the refractive index of the film due to further crystallization and densification. The final refractive index is comparable to that of 95% dense barium titanate ceramics. Re-oxidation did not change the refractive index of the film over the wavelength range from 350 to 650 nm.     

Diffuse optical spectroscopic imaging correlates with final pathological response in breast cancer neoadjuvant chemotherapy

Diffuse optical spectroscopic imaging (DOSI) non-invasively and quantitatively measures tissue haemoglobin, water and lipid. Pilot studies in small groups of patients demonstrate that DOSI may be useful for longitudinal monitoring and predicting breast cancer neoadjuvant chemotherapy pathological response. This study evaluates the performance of a bedside DOSI platform in 34 breast cancer patients followed for several months. DOSI optical endpoints obtained at multiple timepoints are compared with final pathological response. Thirty-six stage II/III breast cancers (34 patients) were measured in vivo with DOSI prior to, in the middle of and after the completion of pre-surgical neoadjuvant chemotherapy. Cancer therapies ranged from standard anthracyclines to targeted therapies. Changes in DOSI-measured parameters at each timepoint were compared against final surgical pathology. Absolute changes in the tumour-to-normal (T/N) ratio of tissue deoxyhaemoglobin concentration (ctHHb) and relative changes in the T/N ratio of a tissue optical index (TOI) were most sensitive and correlate to pathological response. Changes in ctHHb and TOI were significantly different between tumours that achieved pathological complete response (pCR) versus non-pCR. By therapy midpoint, mean TOI-T/N changes were 47±8 versus 20±5 per cent for pCR versus non-pCR subjects, respectively (Z=0.011). Changes in ctHHb and TOI scaled significantly with the degree of pathological response (non-, partial and complete). DOSI measurements of TOI separated pCR from non-pCR by therapy midpoint regardless of drug or dosing strategy. This approach is well suited to monitoring breast tumour response and may provide feedback for optimizing therapeutic outcomes and minimizing side-effects.     

A novel method for pulse shaping of Split Hopkinson tensile bar signals

Split Hopkinson bar (SHB) techniques are commonly used to experimentally characterise materials at high strain-rates. One important aspect of high-strain rate characterisation using SHBs is the necessity to tailor the input pulse to the needs of the material to be tested. Here, a new method to shape the input pulse, specifically developed for tensile SHBs (SHTB), is presented. The new method overcomes several challenges of existing designs, allows for a controlled adjustment of the pulse rising time, and significantly reduces wave dispersion effects.     

Megachiropteran bats (pteropus) utilize human referential stimuli to locate hidden food.

Spontaneous point-following behavior has been considered an indicator of advanced social cognition unique to humans. Recently, it has been suggested that a close evolutionary relationship with humans could result in similar social skills in domesticated species. An alternative view is that the mechanism is not genetic domestication alone but instead a combination of phylogenetic and ontogenetic variables. Here we test the necessity of phylogenetic domestication by investigating the point-following behavior of a captive population of nondomesticated megachiropteran bats (Pteropus pumilus, Pteropus rodricensis, Pteropus conspicillatus, Pteropus vampyrus). Three of five subjects were highly successful in following an unfamiliar human's point to a target location, providing the first empirical evidence of cross-species social referencing in bats. The three successful bats were all born in captivity and socialized to humans early in life, whereas unsuccessful bats were wild-born individuals. This study provides evidence that referential point following is not restricted to domesticated animals and indicates that early experience may be important. Megachiropteran bats may prove to be a useful model for studying social behaviors. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Cyclodimers of p-coumaric and ferulic acids in the cell walls of tropical grasses

Cell walls from leaves and stems of three tropical grasses (Setaria anceps cv Nandi (Schumach) Moss), pangola grass Digitara decumbens Stent and spear grass Heteropogon contortus (L) Beauv ex Roemer & Schultes were extracted with alkali, and ether-soluble fractions were prepared from the acidified solutions. Cyclobutane dimers derived from p-coumaric acid (CA: 3-(4-hydroxypheny) propenoic acid) and ferulic acid (FA: 3-(4-hydroxy-3-methoxyphenyl) propenoic acid) were found in all plant residues. Structural information on the dimers was obtained by gas chromatography-mass spectrometry. Stem cell walls differed from those of leaf in having major dimer components which contained residues tentatively identified as coniferyl alcohol (3-(4-hydroxy-3-methoxyphenyl)-2-propen-l-ol). Species differences in leaf cell wall cyclodimers were evident. Pangola and setaria grasses had dimers mainly derived from FA, whereas spear grass had over 70% of dimers derived from CA. Di-esterification of some dimers in the cell walls was confirmed by the release of dimers containing the reduced forms of CA and FA (coumaryl and coniferyl alcohols respectively) when leaf cell walls were extracted with borohydride. Head to tail dimerisation giving derivatives of truxillic acid (t-2, c-4-diphenyl-r-l, t-3-cyclobutanedicarboxylic acid) predominated, although evidence was obtained for the presence of head-to-head coumaric acid dimers (derivatives of truxinic acid, t-3, t-4-diphenyl-rl, c-2-cyclobutanedicarboxylic acid) in setaria stem and spear grass leaf. The results suggested that cyclodimers in grass cell walls occurred in cross-linking structures of varying complexity between macromolecules, where they would possibly contribute to fibre strength and thus have an adverse efect on the nutritional value of forage.     

The use of meta-analytical tools in risk assessment for food safety

This communication deals with the use of meta-analysis as a valuable tool for the synthesis of food safety research, and in quantitative risk assessment modelling. A common methodology for the conduction of meta-analysis (i.e., systematic review and data extraction, parameterisation of effect size, estimation of overall effect size, assessment of heterogeneity, and presentation of results) is explained by reviewing two meta-analyses derived from separate sets of primary studies of Salmonella in pork. Integrating different primary studies, the first meta-analysis elucidated for the first time a relationship between the proportion of Salmonella-carrier slaughter pigs entering the slaughter lines and the resulting proportion of contaminated carcasses at the point of evisceration; finding that the individual studies on their own could not reveal. On the other hand, the second application showed that meta-analysis can be used to estimate the overall effect of a critical process stage (chilling) on the incidence of the pathogen under study. The derivation of a relationship between variables and a probabilistic distribution is illustrations of the valuable quantitative information synthesised by the meta-analytical tools, which can be incorporated in risk assessment modelling. Strengths and weaknesses of meta-analysis within the context of food safety are also discussed.