Optical properties of reduced LiNbO,

Optical characteristics of H2-reduced LiNbO3 have been studied. The optical transmission in the spectral range 0.3 to 5 mu m is progressively narrowed as the sample is reduced. An absorption band centred at about 2.48 eV is assigned to small polarons. This interpretation is consistent with the published defect structure, transport and spectroscopic reports on reduced LiNbO3. A semi-quantitative analysis of the 2.48 eV absorption band is carried out by employing the Reik and Heese theory (1967) for optical properties of small polarons.

Lung cancer risk of airborne particles for Italian population

Airborne particles, including both ultrafine and supermicrometric particles, contain various carcinogens. Exposure and risk-assessment studies regularly use particle mass concentration as dosimetry parameter, therefore neglecting the potential impact of ultrafine particles due to their negligible mass compared to supermicrometric particles. The main purpose of this study was the characterization of lung cancer risk due to exposure to polycyclic aromatic hydrocarbons and some heavy metals associated with particle inhalation by Italian non-smoking people. A risk-assessment scheme, modified from an existing risk model, was applied to estimate the cancer risk contribution from both ultrafine and supermicrometric particles. Exposure assessment was carried out on the basis of particle number distributions measured in 25 smoke-free microenvironments in Italy. The predicted lung cancer risk was then compared to the cancer incidence rate in Italy to assess the number of lung cancer cases attributed to airborne particle inhalation, which represents one of the main causes of lung cancer, apart from smoking. Ultrafine particles are associated with a much higher risk than supermicrometric particles, and the modified risk-assessment scheme provided a more accurate estimate than the conventional scheme. Great attention has to be paid to indoor microenvironments and, in particular, to cooking and eating times, which represent the major contributors to lung cancer incidence in the Italian population. The modified risk assessment scheme can serve as a tool for assessing environmental quality, as well as setting up exposure standards for particulate matter.

Functional dynamics of the nitrogen balance of sorghum. II. Grain filling period.

Maintenance of green leaf area during grain filling can increase grain yield of sorghum grown under terminal water limitation. This 'stay-green' trait has been related to the nitrogen (N) supply-demand balance during grain filling. This study quantifies the N demand of grain and N translocation rates from leaves and stem and explores effects of genotype and N stress on onset and rate of leaf senescence during the grain filling period. Three hybrids differing in potential height were grown at three levels of N supply under well-watered conditions. Vertical profiles of biomass, leaf area, and N% of leaves, stem and grain were measured at regular intervals. Weekly SPAD chlorophyll readings on main shoot leaves were correlated with observed specific leaf nitrogen (SLN) to derive seasonal patterns of leaf N content. For all hybrids, individual grain N demand was sink determined and was initially met through N translocation from the stem and rachis. Only if this was insufficient did leaf N translocation occur. Maximum N translocation rates from leaves and stem were dependent on their N status. However, the supply of N at canopy scale was also related to the amount of leaf area senescing at any one time. This supply-demand framework for N dynamics explained effects of N stress and genotype on the onset and rate of leaf senescence.

Monitoring exposure to polycyclic aromatic hydrocarbons in an Australian population using pooled urine samples

Integrated exposure to polycyclic aromatic hydrocarbons (PAHs) can be assessed through monitoring of urinary mono-hydroxylated PAHs (OH-PAHs). The aim of this study was to provide the first assessment of exposure to PAHs in a large sample of the population in Queensland, Australia including exposure to infant (0-4. years). De-identified urine specimens, obtained from a pathology laboratory, were stratified by age and sex, and pooled (n. =. 24 pools of 100) and OH-PAHs were measured by gas chromatography-isotope dilution-tandem mass spectrometry. Geometric mean (GM) concentrations ranged from 30. ng/L (4-hydroxyphenanthrene) to 9221. ng/L (1-naphthol). GM of 1-hydroxypyrene, the most commonly used PAH exposure biomarker, was 142. ng/L. The concentrations of OH-PAHs found in this study are consistent with those in developed countries and lower than those in developing countries. We observed no association between sex and OH-PAH concentrations. However, we observed lower urinary concentrations of all OH-PAHs in samples from infants (0-4. years), children (5-14. years) and the elderly (>. 60. year old) compared with samples from other age groups (15-29, 30-44 and 45-59. years) which may be attributed to age-dependent behaviour-specific exposure sources.

A comparison of self-nominated and actual speeds in work zones

Despite significant research on drivers’ speeding behavior in work zones, little is known about how well drivers’ judgments of appropriate speeds match their actual speeds and what factors influence their judgments. This study aims to fill these two important gaps in the literature by comparing observed speeds in two work zones with drivers’ self-nominated speeds for the same work zones. In an online survey, drivers nominated speeds for the two work zones based on photographs in which the actual posted speed limits were not revealed. A simultaneous equation modelling approach was employed to examine the effects of driver characteristics on their self-nominated speeds. The results showed that survey participants nominated lower speeds (corresponding to higher compliance rates) than those which were observed. Higher speeds were nominated by males than females, young and middle aged drivers than older drivers, and drivers with truck driving experience than those who drive only cars. Larger differences between nominated and observed speeds were found among car drivers than truck drivers. These differences suggest that self-nominated speeds might not be valid indicators of the observed work zone speeds and therefore should not be used as an alternative to observed speed data.

Enhancing somatic embryogenesis in avocado (Persea americana Mill.) using a two-step culture system and including glutamine in the culture medium

The development of a more efficient in vitro regeneration system for somatic embryos (SEs) of avocado (Persea americana) would facilitate the development of new superior cultivars for this valuable horticultural crop. In this study, we report a new and efficient method for maintenance and regeneration of avocado SEs. Avocado SEs of four cultivars remained healthy and viable in vitro for 11 months on a medium used for mango somatic embryogenesis, compared with 3-4 months on Murashige and Skoog medium. Various supplements and media modifications were investigated to improve the low conversion rate of regenerated plants from avocado SEs reported previously. The one-step system for regeneration of white-opaque somatic embryos (WOSEs) used solid medium only over a period of 12-14 weeks (sub-culturing every 6 weeks). Addition of praline and glutamine improved the total regeneration from 0 to 17.5% and 10.5%, and plant/shoot recovery from 0 to 12.5% and 5%, respectively. A two-step culture system involving the transfer of WOSEs of cultivar 'Reed' after 6 weeks on solid to liquid medium for 12-15 days as an intermediate step, followed by subculturing again onto solid medium for 6 weeks improved total regeneration to 29% and plant/shoot recovery to 18.3 from 0% when regenerated by subculturing on solid medium only. Supplementation with proline in the solid as well as liquid medium in the two-step culture system at 0.4 g/L increased total regeneration to 35% and plant/shoot recovery to 20%. We were able to achieve highest regeneration using glutamine at 1 g/L in the two-step culture system in terms of both total regeneration (58.3%, including 43.3% bipolar regeneration) and plant/shoot recovery (36.7%) rates, which were significantly higher than in any other treatment investigated. (C) 2013 Elsevier B.V. All rights reserved.

A field investigation into a suspected outbreak of pyrrolizidine alkaloid toxicosis in horses in western Queensland

A disease outbreak investigation was conducted in western Queensland to investigate a rare suspected outbreak of pyrrolizidine alkaloid (PA) toxicosis in horses. Thirty five of 132 horses depastured on five properties on the Mitchell grass plains of western Queensland died in the first six months of 2010. Clinical–pathological findings were consistent with PA toxicosis. A local variety of Crotalaria medicaginea was the only hepatotoxic plant found growing on affected properties. Pathology reports and departure and arrival dates of two brood mares provided evidence of a pre wet season exposure period. All five affected properties experienced a very dry spring and early summer preceded by a large summer wet season. The outbreak was characterised as a point epidemic with a sudden peak of deaths in March followed by mortalities steadily declining until the end of June. The estimated morbidity (serum IGG > 50 IU/L) rate was 76%. Average crude mortality was 27% but higher in young horses (67%) and brood mares (44%). Logistic regression analysis showed that young horses and brood mares and those grazing denuded pastures in December were most strongly associated with dying whereas those fed hay and/or grain based supplements were less likely to die. This is the first detailed study of an outbreak of PA toxicosis in central western Queensland and the first to provide evidence that environmental determinants were associated with mortality, that the critical exposure period was towards the end of the dry season, that supplementary feeding is protective and that denuded pastures and the horses physiological protein requirement are risk factors.

Does manure management affect the latent greenhouse gas emitting potential of livestock manures?

With livestock manures being increasingly sought as alternatives to costly synthetic fertilisers, it is imperative that we understand and manage their associated greenhouse gas (GHG) emissions. Here we provide the first dedicated assessment into how the GHG emitting potential of various manures responds to the different stages of the manure management continuum (e.g., from feed pen surface vs stockpiled). The research is important from the perspective of manure application to agricultural soils. Manures studied included: manure from beef feedpen surfaces and stockpiles; poultry broiler litter (8-week batch); fresh and composted egg layer litter; and fresh and composted piggery litter. Gases assessed were methane (CH4) and nitrous oxide (N2O), the two principal agricultural GHGs. We employed proven protocols to determine the manures’ ultimate CH4 producing potential. We also devised a novel incubation experiment to elucidate their N2O emitting potential; a measure for which no established methods exist. We found lower CH4 potentials in manures from later stages in their management sequence compared with earlier stages, but only by a factor of 0.65×. Moreover, for the beef manures this decrease was not significant (P < 0.05). Nitrous oxide emission potential was significantly positively (P < 0.05) correlated with C/N ratios yet showed no obvious relationship with manure management stage. Indeed, N2O emissions from the composted egg manure were considerably (13×) and significantly (P < 0.05) higher than that of the fresh egg manure. Our study demonstrates that manures from all stages of the manure management continuum potentially entail significant GHG risk when applied to arable landscapes. Efforts to harness manure resources need to account for this.

Scar outcome of children with partial thickness burns: A 3 and 6 month follow up

INTRODUCTION There is a paucity of research investigating the scar outcome of children with partial thickness burns. The aim of this study was to assess the scar outcome of children with partial thickness burns who received a silver dressing acutely. METHOD Children aged 0-15 years with an acute partial thickness burn, ≤10% TBSA were included. Children were originally recruited for an RCT investigating three dressings for partial thickness burns. Children were assessed at 3 and 6 months after re-epithelialization. 3D photographs were taken of the burn site, POSAS was completed and skin thickness was measured using ultrasound imaging. RESULTS Forty-three children returned for 3 and 6 month follow-ups or returned a photo. Days to re-epithelialization was a significant predictor of skin/scar quality at 3 and 6 months (p<0.01). Patient-rated color and observer-rated vascularity and pigmentation POSAS scores were comparable at 3 months (color vs. vascularity 0.88, p<0.001; color vs. pigmentation 0.64, p<0.001), but patients scored higher than the observer at 6 months (color vs. vascularity 0.57, p<0.05; color vs. pigmentation 0.15, p=0.60). Burn depth was significantly correlated with skin thickness (r=0.51, p<0.01). Hypopigmentation of the burn site was present in 25.8% of children who re-epithelialized in ≤2 weeks. CONCLUSION This study has provided information on outcomes for children with partial thickness burns and highlighted a need for further education of this population.

A novel fully validated LC–MS/MS method for quantification of pyridoxal-5′-phosphate concentrations in samples of human whole blood

Quantification of pyridoxal-5´-phosphate (PLP) in biological samples is challenging due to the presence of endogenous PLP in matrices used for preparation of calibrators and quality control samples (QCs). Hence, we have developed an LC-MS/MS method for accurate and precise measurement of the concentrations of PLP in samples (20 µL) of human whole blood that addresses this issue by using a surrogate matrix and minimizing the matrix effect. We used a surrogate matrix comprising 2% bovine serum albumin (BSA) in phosphate buffer saline (PBS) for making calibrators, QCs and the concentrations were adjusted to include the endogenous PLP concentrations in the surrogate matrix according to the method of standard addition. PLP was separated from the other components of the sample matrix using protein precipitation with trichloroacetic acid 10% w/v. After centrifugation, supernatant were injected directly into the LC-MS/MS system. Calibration curves were linear and recovery was > 92%. QCs were accurate, precise, stable for four freeze-thaw cycles, and following storage at room temperature for 17h or at -80 °C for 3 months. There was no significant matrix effect using 9 different individual human blood samples. Our novel LC-MS/MS method has satisfied all of the criteria specified in the 2012 EMEA guideline on bioanalytical method validation.

Association of the microRNA-Single Nucleotide Polymorphism rs2910164 in miR146a with sporadic breast cancer susceptibility: A case control study

Background Breast cancer (BC) is primarily considered a genetic disorder with a complex interplay of factors including age, gender, ethnicity, family history, personal history and lifestyle with associated hormonal and non-hormonal risk factors. The SNP rs2910164 in miR146a (a G to C polymorphism) was previously associated with increased risk of BC in cases with at least a single copy of the C allele in breast cancer, though results in other cancers and populations have shown significant variation. Methods In this study, we examined this SNP in an Australian sporadic breast cancer population of 160 cases and matched controls, with a replicate population of 403 breast cancer cases using High Resolution Melting. Results Our analysis indicated that the rs2910164 polymorphism is associated with breast cancer risk in both primary and replicate populations (p = 0.03 and 0.0013, respectively). In contrast to the results of familial breast cancer studies, however, we found that the presence of the G allele of rs2910164 is associated with increased cancer risk, with an OR of 1.77 (95% CI 1.40–2.23). Conclusions The microRNA miR146a has a potential role in the development of breast cancer and the effects of its SNPs require further inquiry to determine the nature of their influence on breast tissue and cancer.

The influence of impurities on calcium phosphate floc structure and size in sugar solutions

Settling, dewatering and filtration of flocs are important steps in industry to remove solids and improve subsequent processing. The influence of non-sucrose impurities (Ca2+, Mg2+, phosphate and aconitic acid) on calcium phosphate floc structure (scattering exponent, Sf), size and shape were examined in synthetic and authentic sugar juices using X-ray diffraction techniques. In synthetic juices, Sf decreases with increasing phosphate concentration to values where loosely bound and branched flocs are formed for effective trapping and removal of impurities. Although, Sf did not change with increasing aconitic acid concentration, the floc size significantly decreased reducing the ability of the flocs to remove impurities. In authentic juices, the flocs structures were marginally affected by increasing proportions of non-sucrose impurities. However, optical microscopy indicated the formation of well-formed macro-floc network structures in sugar cane juices containing lower proportions of non-sucrose impurities. These structures are better placed to remove suspended colloidal solids.

A total synthesis of the epoxyquinone based antifungal natural product (±)-ambuic acid

A total synthesis of the recently isolated polyketide natural product (+/-)-ambuic acid has been accomplished from the readily available Diels-Alder adduct of cyclopentadiene and 2-allyl-p-benzoquinone through a simple sequence with sound stereocontrol. (c) 2005 Elsevier Ltd. All rights reserved.

Characterization of Alkali Induced Formation of Lanthionine, Trisulfides, and Tetrasulfides from Peptide Disulfides using Negative Ion Mass Spectrometry

Peptide disulfides are unstable under alkaline conditions, resulting in the formation of products containing lanthionine and polysulfied linkages. Electrospray ionization mass spectrometry has been used to characterize major species obtained when cyclic and acyclic peptide disulfides are exposed to alkaline media. Studies on a model cyclic peptide disulfide (Boc - Cys - Pro - Leu - Cys - NHMe) and an acyclic peptide, oxidized glutathione, bis ((gamma)Glu Cys - Gly - COOH), are described. Disulfide cleavage reactions are initiated by the abstraction of (CH)-H-alpha or (CH)-H-beta protons of Cys residues, with Subsequent elimination of H2S or H2S2. The buildup of reactive thiol species which act on intermediates containing dehydroalanine residues, rationalizes the formation of lanthionine and polysulfide products. In the case of the cyclic peptide disulfide, the formation of cyclic products is facilitated by the intramolecular nature of the Michael addition reaction of thiols to the dehydroalanine residue. Mass spectral evidence for the intermediate species is presented by using alkylation of thiol groups as a trapping method. Mass spectral fragmentation in the negative ion mode of the peptides derived from trisulfides and tetrasulfides results in elimination of S-2. (J Am Soc Mass Spectrom 2009, 20, 783-791) (C) 2009 American Society for Mass Spectrometry.