Screening Subclinical Keratoconus With Placido-Based Corneal Indices

Purpose. To assess in a sample of normal, keratoconic, and keratoconus (KC) suspect eyes the performance of a set of new topographic indices computed directly from the digitized images of the Placido rings. Methods. This comparative study was composed of a total of 124 eyes of 106 patients from the ophthalmic clinics Vissum Alicante and Vissum Almería (Spain) divided into three groups: control group (50 eyes), KC group (50 eyes), and KC suspect group (24 eyes). In all cases, a comprehensive examination was performed, including the corneal topography with a Placidobased CSO topography system. Clinical outcomes were compared among groups, along with the discriminating performance of the proposed irregularity indices. Results. Significant differences at level 0.05 were found on the values of the indices among groups by means of Mann-Whitney-Wilcoxon nonparametric test and Fisher exact test. Additional statistical methods, such as receiver operating characteristic analysis and K-fold cross validation, confirmed the capability of the indices to discriminate between the three groups. Conclusions. Direct analysis of the digitized images of the Placido mires projected on the cornea is a valid and effective tool for detection of corneal irregularities. Although based only on the data from the anterior surface of the cornea, the new indices performed well even when applied to the KC suspect eyes. They have the advantage of simplicity of calculation combined with high sensitivity in corneal irregularity detection and thus can be used as supplementary criteria for diagnosing and grading KC that can be added to the current keratometric classifications.

Agricultural Stabilization and Conservation Service payment-in-kind (PIK) program : a review of PIK program compliance and effectiveness.

"Audit report no. 3621-4-KC."

Coherent charge and spin transfer in a quantum dot coupled to a mesoscopic ring

We study the effect of coherent charge and spin fluctuations in a mesoscopic device composed of a quantum dot and an Aharonov-Bohm ring. We show that, while the charge fluctuations suppress the persistent current algebraically as a function of the level spacing of the ring, the spin fluctuations give rise to a completely different behavior. We discuss the origin of this difference in relation to the peculiar nature of the ground state in the Kondo limit. (C) 2003 Elsevier B.V. All rights reserved.

Gene codon composition determines differentiation-dependent expression of a viral capsid gene in keratinocytes in vitro and in vivo

By establishing mouse primary keratinocytes (KCs) in culture, we were able, for the first time, to express papillomavirus major capsid (L1) proteins by transient transfection of authentic or codon-modified L1 gene expression plasmids. We demonstrate in vitro and in vivo that gene codon composition is in part responsible for differentiation-dependent expression of L1 protein in KCs. L1 mRNA was present in similar amounts in differentiated and undifferentiated KCs transfected with authentic or codon-modified L1 genes and had a similar half-life, demonstrating that L1 protein production is posttranscriptionally regulated. We demonstrate further that KCs substantially change their tRNA profiles upon differentiation. Aminoacyl-tRNAs from differentiated KCs but not undifferentiated KCs enhanced the translation of authentic L1 mRNA, suggesting that differentiation-associated change to tRNA profiles enhances L1 expression in differentiated KCs. Thus, our data reveal a novel mechanism for regulation of gene expression utilized by a virus to direct viral capsid protein expression to the site of virion assembly in mature KCs. Analysis of two structural proteins of KCs, involucrin and keratin 14, suggests that translation of their mRNAs is also regulated, in association with KC differentiation in vitro, by a similar mechanism

Altered fungal sensitivity to a plant antimicrobial peptide through over-expression of yeast cDNAs

A yeast cDNA expression library was screened to identify genes and cellular processes that influence fungal sensitivity to a plant antimicrobial peptide. A plasmid-based, GAL1 promoter-driven yeast cDNA expression library was introduced into a yeast genotype susceptible to the antimicrobial peptide MiAMP1 purified from Macadamia integrifolia. Following a screen of 20,000 cDNAs, three yeast cDNAs were identified that reproducibly provided transformants with galactose-dependent resistance to MiAMP1. These cDNAs encoded a protein of unknown function, a component (VMA11) of the vacuolar H+-ATPase and a component (cytochrome c oxidase subunit VIa) of the mitochondrial electron transport chain, respectively. To identify genes that increased sensitivity to MiAMP1, the yeast cDNA expression library was introduced into a yeast mutant with increased resistance to MiAMP1. From 11,000 cDNAs screened, two cDNA clones corresponding to a ser/thr kinase and a ser/thr phosphatase reproducibly increased MiAMP1 susceptibility in the mutant in a galactose-dependent manner. Deletion mutants were available for three of the five genes identified but showed no change in their sensitivity to MiAMP1, indicating that these genes could not be detected by screening of yeast deletion mutant libraries. Yeast cDNA expression library screening therefore provides an alternative approach to gene deletion libraries to identify genes that can influence the sensitivity of fungi to plant antimicrobial peptides.

The mode of action of the plant antimicrobial peptide MiAMP1 differs from that of its structural homologue, the yeast killer toxin WmKT

The plant antimicrobial peptide MiAMP1 from Macadamia integrifolia and the yeast killer toxin peptide WmKT from Williopsis mrakii are structural homologues. Comparative studies of yeast mutants were performed to test their sensitivity to these two antimicrobial peptides. No differences in susceptibility to MiAMP1 were detected between wild-type and several WmKT-resistant mutant yeast strains. A yeast mutant MT1, resistant to MiAMP1 but unaffected in its susceptibility to plant defensins and hydrogen peroxide, also did not show enhanced tolerance towards WmKT. It is therefore probable that the Greek key beta-barrel structure shared by MiAMP1 and WmKT provides a robust structural framework ensuring stability for the two proteins but that the specific action of the peptides depends on other motifs. (C) 2004 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved.

Extreme learning machine for predicting HLA-peptide binding

Machine learning techniques have been recognized as powerful tools for learning from data. One of the most popular learning techniques, the Back-Propagation (BP) Artificial Neural Networks, can be used as a computer model to predict peptides binding to the Human Leukocyte Antigens (HLA). The major advantage of computational screening is that it reduces the number of wet-lab experiments that need to be performed, significantly reducing the cost and time. A recently developed method, Extreme Learning Machine (ELM), which has superior properties over BP has been investigated to accomplish such tasks. In our work, we found that the ELM is as good as, if not better than, the BP in term of time complexity, accuracy deviations across experiments, and most importantly - prevention from over-fitting for prediction of peptide binding to HLA.

Freshman 15: Fact or fiction?

Objective: The objective of this study was to investigate changes in body weight, BMI, body composition, and fat distribution among freshman women during their 1st year of college. Research Methods and Procedures: Freshman women during the 2004 to 2005 academic year were recruited to participate. The initial baseline visit occurred within the first 6 weeks of the fall 2004 semester, with the follow-up visit occurring during the last 6 weeks of the spring 2005 semester. At each visit, height, weight, BMI, waist and hip circumferences, and body composition (by DXA) were obtained. Results: One hundred thirty-seven participants completed both the fall and spring visits. Significant (p < 0.0001) increases between the fall and spring visits were observed for body weight (58.6 vs. 59.6 kg), BMI (21.9 vs. 22.3), percentage body fat (28.9 vs. 29.7), total fat mass (16.9 vs. 17.7 kg), fat-free mass (38.1 vs. 38.4 kg), waist circumference (69.4 vs. 70.3 cm), and hip circumference (97.4 vs. 98.6 cm), with no significant difference observed in the waist-to-hip ratio (0.71 vs. 0.71; p = 0.78). Discussion: Although statistically significant, changes in body weight, body composition, and fat mass were modest for women during their freshman year of college. These results do not support the purported freshman 15 weight gain publicized in the popular media.

Passive air sampling for persistent organic pollutants: Introductory remarks to the special issue

There have been a number of developments in the need, design and use of passive air samplers (PAS) for persistent organic pollutants (POPs). This article is the first in a Special Issue of the journal to review these developments and some of the data arising from them. We explain the need and benefit of developing PAS for POPs, the different approaches that can be used, and highlight future developments and needs. (c) 2006 Elsevier Ltd. All rights reserved.

Selenium binding protein 1 in ovarian cancer

Selenium binding protein I (SELENBP1) was identified to be the most significantly down-regulated protein in ovarian cancer cells by a membrane proteome profiling analysis. SELENBP1 expression levels in 4 normal ovaries, 8 benign ovarian tumors, 12 borderline ovarian tumors and 141 invasive ovarian cancers were analyzed with immunohistochemical assay. SELENBP1 expression was reduced in 87% cases of invasive ovarian cancer (122/141) and was significantly reduced in borderline tumors and invasive cancers (p < 0.001). Cox multivariate analysis within the 141 invasive cancer tissues showed that SELENBP1 expression score was a potential prognostic indicator for unfavorable prognosis of ovarian cancer (hazard ratio [HR], 2.18; 95% CI = L22-190; p = 0.009). Selenium can disrupt the androgen pathway, which has been implicated in modulating SELENBP1 expression. We investigated the effects of selenium and androgen on normal human ovarian surrace epithelial (HOSE) cells and cancer cells. Interestingly, SELENBP1 mRNA and protein levels were reduced by androgen and elevated by selenium treatment in the normal HOSE cells, whereas reversed responses were observed in the ovarian cancer cell lines. These results suggest that changes of SELENBP1 expression in malignant ovarian cancer are an indicator of aberration of selenium/androgen pathways and may reveal prognostic information of ovarian cancer. (c) 2005 Wiley-Liss, Inc.

The critical dietary potassium concentration for induction of mineral disorders in non-lactating Welsh Mountain sheep

Diets with more than 30 g K/kg DM have previously been associated with hypomagnesaemia in grazing cattle, and to test whether such diets lead to mineral disorders in sheep, the absorption of Mg and other elements was investigated using experimental diets to which KC I had been added to provide 27, 29, 32 or 34 g K/kg DM. The apparent absorption, balance and apparent retention of Mg, and to a lesser extent Ca, were reduced for sheep offered the diets with 32 or 34 g K/kg DM. The absorption and retention of K, Na, P, Zn, Pb and Cd was not affected by treatment. The blood intracellular Ca concentration was reduced by the diets with 29, 32 or 34 g K/kg DM, compared to the diet with 27 g K/kg DM, but the concentration of other elements was unaffected. Blood plasma Ca concentration was increased at the highest level of K inclusion, providing evidence of mild hyperkalaemia and the involvement of Ca homeostatic mechanisms. It is concluded that Mg absorption by sheep will be impaired if the diet contains more than 30 g K/kg DM, equivalent to an intake of approximately 13 g K/d, but that a high K diet may be beneficial before parturition to accustom the sheep to Ca mobilization before lactation. (c) 2005 Elsevier B.V. All rights reserved.

Instantaneous RRMI of iron rods in reduced gravity

Standard upward-burning promoted ignition tests (“Standard Test Method for Determining the Combustion Behavior of Metallic Materials in Oxygen-Enriched Atmospheres,” ASTM G4-124 [1] or “Flammability, Odor, Offgassing, and Compatibility Requirements and Test Procedures for Materials in Environments that Support Combustion,” NASA-STD-6001, NASA Test 17 [2]) were performed on cylindrical iron (99.95% pure) rods in various oxygen purities (95.0–99.98%) in reduced gravity onboard NASA JSC's KC-135 to investigate the effect of gravity on the regression rate of the melting interface. Visual analysis of experiments agrees with previous published observations showing distinct motions of the molten mass attached to the solid rod during testing. Using an ultrasonic technique to record the real-time rod length, comparison of the instantaneous regression rate of the melting interface and visual recording shows a non-steady-state regression rate of the melting interface for the duration of a test. Precessional motion is associated with a higher regression rate of the melting interface than for test periods in which the molten mass does not show lateral motion. The transition between the two types of molten mass motion during a test was accompanied by a reduced regression rate of the melting interface, approximately 15–50% of the average regression rate of the melting interface for the entire test.

A study of liquid-liquid extraction in a sieve plate column

The literature relating to sieve plate liquid extraction columns and relevant hydrodynamic phenomena have been surveyed. Mass transfer characteristics during drop formation, rise and coalescence, and related models were also reviewed. Important design parameters i.e. flooding, dispersed phase hold-up, drop size distribution, mean drop size, coalescence/flocculation zone height beneath a plate and jetting phenomena were investigated under non-mass transfer and mass transfer conditions in a 0.45m diameter, 2.3m high sieve plate column. This column had provision for four different plate designs, and variable plate spacing and downcomer heights, and the system used was Clairsol `350' (dispersed) - acetone - deionised water (continuous) with either direction of mass transfer. Drop size distributions were best described by the functions proposed by Gal-or, and then Mugele-Evans. Using data from this study and the literature, correlations were developed for dispersed phase hold-up, mean drop size in the preferred jetting regime and in the non-jetting regime, and coalescence zone height. A method to calculate the theoretical overall mass transfer coefficient allowing for the range of drop sizes encountered in the column gave the best fit to experimental data. This applied the drop size distribution diagram to estimate the volume percentage of stagnant, circulating and oscillating drops in the drop population. The overall coefficient Kcal was then calculated as the fractional sum of the predicted individual single drop coefficients and their proportion in the drop population. In a comparison between the experimental and calculated overall mass transfer coefficients for cases in which all the drops were in the oscillating regime (i.e. 6.35mm hole size plate), and for transfer from the dispersed(d) to continuous(c) phase, the film coefficient kd predicted from the Rose-Kintner correlation together with kc from that of Garner-Tayeban gave the best representation. Droplets from the 3.175mm hole size plate, were of a size to be mainly circulating and oscillating; a combination of kd from the Kronig-Brink (circulating) and Rose-Kintner (oscillating) correlations with the respective kc gave the best agreement. The optimum operating conditions for the SPC were identified and a procedure proposed for design from basic single drop data.