Characterization of pyrogenic black carbon by desorption atmospheric pressure photoionization Fourier transform ion cyclotron resonance mass spectrometry

We present a new method for molecular characterization of intact biochar directly, without sample preparation or pretreatment, on the basis of desorption atmospheric pressure photoionization (DAPPI) coupled to Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. Conventional ionization methods (e.g., electrospray or atmospheric pressure photoionization) for characterization of natural organic matter have limited utility for the characterization of chars due to incomplete solubility in common solvents. Therefore, direct ionization techniques that do not require sample dissolution prior to analysis are ideal. Here, we apply DAPPI FTICR mass spectrometry to enable the first molecular characterization of uncharred parent oak biomass and after combustion (250 °C) or pyrolysis (400 °C). Parent oak is primarily composed of cellulose-, lignin-, and resin-like compounds. Oak combusted at 250 °C contains condensed aromatic compounds with low H/C and O/C ratios while retaining compounds with high H/C and O/C ratios. The bimodal distribution of aromatic and aliphatic compounds observed in the combusted oak sample is attributed to incomplete thermal degradation of lignin and hemicellulose. Pyrolyzed oak constituents exhibit lower H/C and O/C ratios: approximately three-quarters of the identified species are aromatic. DAPPI FTICR MS results agree with bulk elemental composition as well as functional group distributions determined by elemental analysis and solid state (13)C NMR spectroscopy. Complete molecular characterization of biomass upon thermal transformation may provide insight into the biogeochemical cycles of biochar and future renewable energy sources, particularly for samples currently limited by solubility, separation, and sample preparation.     

Evaluation of the University of Minnesota Tri-plate and 3M Petrifilm for the isolation of Staphylococcus aureus and Streptococcus species from clinically mastitic milk samples

The primary objective was to compare microbiological results of the University of Minnesota Tri-plate and the 3M Petrifilm Staph Express (STX) Count Plate to standard culture techniques for identification of clinical mastitis caused by Staphylococcus aureus. The secondary objective was to evaluate the Tri-plate's ability to differentiate Streptococcus spp. from other gram-positive organisms. The tests were evaluated using clinically positive mastitic milk samples (n = 282) to determine their ability to diagnose the pathogens of interest. A Tri-plate was classified positive for Staph. aureus when at least 1 colony exhibiting β-hemolysis was present on the Factor media portion of the plate. When the plate was used in this manner and read by a trained laboratory technician, the sensitivity of the Tri-plate was 97.9% and the specificity was 81.8%. When the Tri-plate was evaluated by the laboratory technician for its ability to diagnose Streptococcus spp., both sensitivity and specificity of the test were very good (92.6 and 89.5%, respectively). Using the Petrifilm, samples were classified as positive for Staph. aureus if any red-violet colonies were present on the Petrifilm after an initial 24-h incubation. When used in this manner, the Petrifilm had a sensitivity of 97.4% and a specificity of 76.1%. Further evaluation of the Petrifilm was done using the STX disk, which was used to confirm the presence of Staph. aureus. When using the presence of 1 pink colony on the disk, the sensitivity of the Petrifilm was 92.1% and the specificity was 93.1%. Both the Tri-plate and the 3M STX Petrifilm successfully diagnosed Staph. aureus in clinical milk samples when used in a laboratory setting and the Tri-plate successfully differentiated Streptococcus spp. from other gram-positive organisms.     

Stereospecific formation of a ternary complex of (S)-α,β-fluoromethylene-dATP with DNA pol β

The influence of water: crystallization of (R/S)-α,β-CHF-dATP with the preorganized pol β-DNA complex shows that (S)-α,β-CHF-dATP is preferentially bound to the active site with the C=F fluorine proximal to a structural water bound to Asp276.     

RERBEE: robust efficient registration via bifurcations and elongated elements applied to retinal fluorescein angiogram sequences

We present RERBEE (robust efficient registration via bifurcations and elongated elements), a novel feature-based registration algorithm able to correct local deformations in high-resolution ultra-wide field-of-view (UWFV) fluorescein angiogram (FA) sequences of the retina. The algorithm is able to cope with peripheral blurring, severe occlusions, presence of retinal pathologies and the change of image content due to the perfusion of the fluorescein dye in time. We have used the computational power of a graphics processor to increase the performance of the most computationally expensive parts of the algorithm by a factor of over × 1300, enabling the algorithm to register a pair of 3900 × 3072 UWFV FA images in 5-10 min instead of the 5-7 h required using only the CPU. We demonstrate accurate results on real data with 267 image pairs from a total of 277 (96.4%) graded as correctly registered by a clinician and 10 (3.6%) graded as correctly registered with minor errors but usable for clinical purposes. Quantitative comparison with state-of-the-art intensity-based and feature-based registration methods using synthetic data is also reported. We also show some potential usage of a correctly aligned sequence for vein/artery discrimination and automatic lesion detection.     

Selenium levels in cows fed pasture and concentrates or a total mixed ration and supplemented with selenized yeast to produce milk with supra-nutritional selenium concentrations

Seventy multiparous Holstein-Friesian cows were fed different amounts of pasture and concentrates, or a total mixed ration (TMR), for 42 d in mid-lactation to test the hypothesis that the concentration of Se in milk would depend on the amount of Se consumed, when the Se is primarily organic in nature, regardless of the diet of the cows. Of the 70 cows, 60 grazed irrigated perennial pasture at daily allowances of either 20 or 40 kg of dry matter (DM)/cow. These cows received 1 of 3 amounts of concentrates, either 1, 3, or 6 kg of DM/cow per day of pellets, and at each level of concentrate feeding, the pellets were formulated to provide 1 of 2 quantities of Se from Se yeast, either about 16 or 32 mg of Se/d. The other 10 cows were included in 2 additional treatments where a TMR diet was supplemented with 1 kg of DM/d of pellets formulated to include 1 of the 2 quantities of supplemental Se. Total Se intakes ranged from 14.5 to 35.9 mg/d, and of this, the Se-enriched pellets provided 93, 91, and 72% of the Se for cows allocated 20 and 40 kg of pasture DM/d or the TMR, respectively. No effects of the amount of Se consumed on any milk production variable, or on somatic cell count, body weight, and body condition score, for either the pasture-fed or TMR-fed cows were found. Milk Se concentrations responded quickly to the commencement of Se supplementation, reaching 89% of steady state levels at d 5. When milk Se concentrations were at steady state (d 12 to 40), each 1 mg of Se eaten increased the Se concentration of milk by 5.0 μg/kg (R² = 0.97), and this response did not seem to be affected by the diet of the cows or their milk production. The concentration of Se in whole blood was more variable than that in milk, and took much longer to respond to change in Se status, but it was not affected by diet at any time either. For the on-farm production of Se-enriched milk, it is important to be able to predict milk Se concentration from Se input. In our study, type of diet did not affect this relationship.     

The Effects of Irradiation, High Hydrostatic Pressure, and Temperature during Pressurization on the Characteristics of Cooked-reheated Salmon and Catfish Fillets

ABSTRACT: Fully‐cooked salmon and catfish fillets were treated by ionizing radiation (0, 3, or 6 kGy), high hydrostatic pressure (HHP) (0, 414, or 690 MPa), 2 different temperatures during pressurization (ambient‐HHP approximately equal to 21 °C, or heated‐HHP = 70 °C), and combinations of the treatments. Kramer shear values increased for salmon and catfish fillets treated by HHP, heated‐HHP, and a combination treatment. Tenderness and juiciness scores of salmon and catfish fillets were lower with HHP, heated‐HHP, and a combination treatment. Irradiation decreased CIE a* values of salmon, and CIE b* values of salmon and catfish. Irradiation increased tenderness and juiciness scores of salmon and increased flavor intensity of catfish.     

Inhibition of Human α‐Methylacyl CoA Racemase (AMACR): a Target for Prostate Cancer

The enzyme α‐methylacyl CoA racemase (AMACR) is involved in the metabolism of branched‐chain fatty acids and has been identified as a promising therapeutic target for prostate cancer. By using the recently available human AMACR from HEK293 kidney cell cultures, we tested a series of new rationally designed inhibitors to determine the structural requirements in the acyl component. An N‐methylthiocarbamate (K_i=98 nM ), designed to mimic the proposed enzyme‐bound enolate, was found to be the most potent AMACR inhibitor reported to date.     

The Role of Collaborative Reflection on Shaping Engineering Faculty Teaching Approaches

Over the last several years, engineering faculty and learning scientists from four universities worked in collaboration to develop educational materials to improve the quality of faculty teaching and student learning. Guided by the How People Learn (HPL) framework, engineering faculty worked in collaboration with learning scientists to develop learner‐centered, student‐focused instructional methods. In consultation with learning scientists, engineering faculty carried out educational inquiry in their classrooms aimed at investigating student learning and enhancing instruction. In this paper we discuss the extent to which faculty engaged in these collaborative endeavors and how their teaching approaches differed as a result of their level of engagement. Study findings reveal the role that collaborative reflection plays in shaping teaching approaches. Results from this study provide insights for researchers and other practitioners in engineering and higher education interested in implementing engineering faculty development programs to optimize the impact on teaching.     

Spatial and temporal variation in distribution of larval lake whitefish in eastern Lake Ontario: Signs of recovery?

The lake whitefish (Coregonus clupeaformis) is one of the native Lake Ontario fishes that declined severely over the past century. Recent evidence of larval lake whitefish production in a historic spawning area (Chaumont Bay) might signal a recovery of this species in New York waters. We surveyed coastal and open water areas to evaluate densities and estimate total abundance of larval lake whitefish in Chaumont Bay. Other historic spawning areas and embayments with appropriate spawning and nursery habitat were also surveyed, but only a few larvae were found outside of Chaumont Bay. Lake whitefish larvae were found in every embayment sampled within Chaumont Bay, with larval densities of nearly 600/1000 m² in some samples. Greatest abundances occurred in the northern sectors and near the mouth of the bay. Open water densities were generally less than half that of nearshore sites. The total bay-wide estimate for 2005 was approximately 644,000 lake whitefish larvae, but dropped to 230,000–400,000 in 2006 and 2007, respectively. Mean larval growth rates (0.36 mm/day) did not differ by year, but were consistently higher in early May than in late April. Lake whitefish production in Chaumont Bay is encouraging for this species, but the cause and persistence of the decline after 2005 can be determined only by continued monitoring. Other possible bottlenecks of survival may exist at juvenile and adult stages and could significantly affect recruitment dynamics. This species is sensitive to normal climatic fluctuations and increased variability associated with global climatic change could make winter nursery conditions unfavorable for this species.     

How pervasive are relative age effects in secondary school education?

Relative age effects (RAEs; R. H. Barnsley, A. H. Thompson, & P. E. Barnsley, 1985) convey school attainment (dis)advantages depending on whether one is relatively older or younger within annually age-grouped cohorts. In the present study, the authors examined the pervasiveness of RAEs by examining (a) attainment in 4 secondary school subjects, (b) attainment consistency across subjects, (c) pupils enrolled in gifted and talented programs, (d) pupils referred for learning support or identified as having special educational needs, and (e) whether RAEs were related to pupil attendance. For 2004–2005, attainment, program participation, and attendance data for 657 pupils (aged 11–14) at a secondary school in North England were analyzed. Relatively older pupils (i.e., September–November born) attained significantly higher in subjects (except for English), were more likely to attain consistently high scores across subject areas, and be enrolled in gifted and talented programs. In contrast, relatively younger pupils (i.e., January–August born) were overrepresented in learning support referrals and identified as having special educational needs, and were more likely to be among the lowest 20% of attainment and attendees, attending on average school 6 days less. RAEs are pervasive and systematic across the curriculum, implicating maturational and psychological mechanisms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)