bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of a time-dependent background error covariance matrix on air quality analysis
Authors: Jaumouillé E. , Massart S. , Piacentini A. , Cariolle D. , Peuch V.-H.
Published: April 2012

Abstract. In this article we study the influence of different characteristics of our assimilation system on the surface ozone analyses over Europe. Emphasis is placed on the evaluation of the background error covariance matrix (BECM). Data assimilation systems require a BECM in order to obtain an optimal representation of the physical state. A posteriori diagnostics are an efficient way to check the consistency of the used BECM. In this study we derived a diagnostic to estimate the BECM. On the other hand an increasingly used approach to obtain such a covariance matrix is to estimate it from an ensemble of perturbed assimilation experiments. We applied this method, combined with variational assimilation, while analysing the surface ozone distribution over Europe. We first show that the resulting covariance matrix is strongly time (hourly and seasonally) and space dependent. We then built several configurations of the background error covariance matrix with none, one or two of its components derived from the ensemble estimation. We used each of these configurations to produce surface ozone analyses. All the analyses are compared between themselves and compared to assimilated data or data from independent validation stations. The configurations are very well correlated with the validation stations, but with varying regional and seasonal characteristics. The largest correlation is obtained with the experiments using time and space dependent correlation of the background errors. Results show that our assimilation process is efficient in bringing the model assimilations closer to the observations than the direct simulation, but we cannot conclude which BECM configuration is the best. The impact of the background error covariances configuration on four-days forecasts is also studied. Although mostly positive, the impact depends on the season and lasts longer during the winter season.
Role-Play: Taking the Line of Least Resistance
Authors: Zainol Abidin Mohamad Jafre , Hosseini Monir Sadat , Hosseini Monir Sadat
Published: April 2012

Today, one of the main concerns in second language acquisition is to learn how to communicate orally with others. So speaking has played an increasingly essential role in second language settings. However, in many universities, ESL students rarely communicate effectively in English with other people. They would rather remain passive when a communicative task is assigned. Such a phenomenon has long left many ESL practitioners defeated. This had prompted the research to ascertain the effectiveness of role-play in eradicating the problem. Using Kolb (1984) model in the ESL classroom experimentally, after fourteen weeks, the outcomes showed that role-play is an effective technique to enhance the learners' confidence and their oral competency.
Customer Service Quality Perception of Internet Banking
Authors: Hassan M. Taimoor , Mukhtar Aqeel , Ullah Rana Kaleem , Shafique Huzaifah , Rehmna Shafi Ur , Anwar Abia
Published: April 2012

Purpose: The purpose of this study is to find out the determinants that mainly affect the customer service quality perception of internet banking amongst genders and different age groups. Design/methodology/approach: Sample of 120 internet banking customers was used to gather data, which was further utilized to find out how 8 major determinants affect the customer service quality perception of internet banking. Findings: The research found that Web design, security, trust, product diversification, credibility, collaboration, access and communication strongly affect the customer perception about the quality of internet banking service. Research limitations/ implication: The data was gathered from the banks in Bahawalpur which limited the scope of this study particularly to this region so future research can be done to gathered data from all over the Pakistan so that the cross cultural factors could be identified clearly. Keywords:                  Service Quality Perception, Dimensions of Internet Banking, Bahawalpur.
Study of Request Strategies Employed By Libyan and Malay POSTGRADUATE Students at USM
Authors: Youssef Awad Mohamed S
Published: April 2012

There has been considerable attention from the cross-cultural pragmatics literature towards the various strategies speakers use when performing the requesting speech act. Speech acts are often used when communicating verbally in either the first language or a second language. This paper presents a study into the similarities and differences in the request strategies by Malaysian and Libyan postgraduate students at USM. The study majorly uses information from existing literature on what other people have written on this topic. The study findings will give new insights to the directness and requesting behaviors within Libyan and Malaysian students and the challenges of cross-linguistic and cross-cultural communication. This study has cultural implications such as awareness of the request strategies used in one culture compared to another culture. This study tackles the ability of Libyan and Malay learners to apply requests in English.  Furthermore, this study attempts to provide explanations for pragmatic errors that Libyan and Malay learners may perform.   Keywords: Cross-Cultural, Strategies, Modifications, Linguistic.
Objective and Goal Setting in Government Agencies in Nigeria and its Implications on Operational Outcomes
Authors: Michael Nwidobie Barine
Published: April 2012

The design of corporate plans is hierarchical in nature with corporate objectives determining the specific achievable goals and strategies to achieve set objectives. Government agencies in Nigeria use established templates for setting specific goals followed by broad objectives for achieving the goals; explaining the non-achievement of results annually in contravention of the empirically tested pattern of objective setting, followed by specific goals setting and determination of strategies for achieving the set goals necessitating the reversal of the planning steps to broad objective setting, followed by specific goals setting for the achievement of the broad objectives and the deployment of necessary strategies to achieve the goals. Key Words: corporate plan, corporate objectives, corporate goals and strategies.
Applied Error Analysis of Written Production of English Essays of Tenth Grade Students in Ajloun Schools, Jordan
Authors: Zawahreh Firas Ali Suleiman
Published: April 2012

The objective of this study was investigating the written English errors of tenth grade students in females and males schools in Ajloun, Jordan. It was conducted on purpose of  identifying the written errors of English committed by the tenth grade, estimating the predominant errors and the least ones and explaining the causes of the written errors of English committed by the tenth grade students The sample of study consisted of 350 students selected randomly from group of schools in Ajloun. The students were asked to write a free essay about " A journey to the ancient city of Jerash in Jordan" in an ordinary English language exercise in the class. Then the essays collected and analyzed depending on a table of errors adopted from a Ph.D. of ( wakkad,1980).The findings were: First, the most predominant errors among tenth grade students in Ajloun schools within morphology were errors of lack of agreement between subject and the main verb. Second, the most predominant errors among tenth grade students in Ajloun schools within function words were errors of insertion of prepositions. Third, the most predominant errors among tenth grade students within syntax were errors of omission of the main verb. Fourth, the most predominant errors among tenth grade students within tenses were errors of using present instead of past. Fifth, the most predominant errors among tenth grade students within lexical items were errors of lexical items wrongly used in place of others.
Retinal involvement in nephrotic syndrome secondary to minimal change disease
Authors: De Benedetto Umberto , Pastore Marco R. , Parodi Maurizio Battaglia , Bandello Francesco , Pierro Luisa
Published: April 2012

Purpose

Nephrotic syndrome is a kidney disorder characterized by loss of different plasmatic proteins resulting in different peripheral tissue edemas. No ocular complications have been reported in nephrotic syndrome secondary to primary glomerular disease.

Methods

A 24-year-old woman was referred to emergency service for acute generalized edema, associated with bilateral visual impairment and metamorphopsia. A diagnosis of nephrotic syndrome was made. The patient was treated with diuretic therapy.

Results

At first ophthalmologic evaluation, the woman presented best-corrected visual acuity of 20/32 in the right eye and 20/40 in the left eye and a dome-shaped bilateral neurosensorial retinal detachment and macular edema studied with spectral-domain optical coherence tomography. The patient underwent furosemide treatment. At follow-up evaluation 6 days later, best-corrected visual acuity improved to 20/20 in both eyes and restoration of normal retinal anatomy was demonstrated.

Conclusions

Sequestration of interstitial fluids, which leads to classic generalized edema in nephrotic syndrome, could be the origin of interstitial accumulation of fluids in the retinal layers.
Simultaneous Determination of Atorvastatin Calcium, Ezetimibe, and Fenofibrate in a Tablet Formulation by HPLC
Authors: Patel Archita , MaCwana Chhaya , Parmar Vishal , Patel Samir
Published: April 2012

An accurate, simple, reproducible, and sensitive HPLC method was developed and validated for the simultaneous determination of atorvastatin calcium, ezetimibe, and fenofibrate in a tablet formulation. The analyses were performed on an RP C18 column, 150 × 4.60 mm id, 5 μm particle size. The mobile phase methanol–acetonitrile–water (76 + 13 + 11, v/v/v), was pumped at a constant flow rate of 1 mL/min. UV detection was performed at 253 nm. Retention times of atorvastatin calcium, ezetimibe, and fenofibrate were found to be 2.25, 3.68, and 6.41 min, respectively. The method was validated in terms of linearity, precision, accuracy, LOD, LOQ, and robustness. The response was linear in the range 2–10 μg/mL (r2 = 0.998) for atorvastatin calcium, 2–10 μg/mL (r2 = 0.998) for ezetimibe, and 40–120 μg/mL (r2 = 0.998) for fenofibrate. The developed method can be used for routine quality analysis of the drugs in the tablet formulation.
Determination of Streptomycin Residue in Cucumber and Chinese Cabbage by High-Performance Liquid Chromatography with Postcolumn Derivatization and Fluorometric Detection
Authors: Chen Benjing , Zhang Hongyan , Lin Baoxiang , Ge Jing , Qiu Lihong
Published: April 2012

A sensitive and accurate method was developed for the determination of streptomycin using HPLC followed by postcolumn derivatization and fluorometric detection. The analyte was extracted, using aqueous solution from cucumber and Chinese cabbage, by a two-step SPE procedure. The extraction, cleanup, and chromatography conditions were optimized, and the performance of the analysis method was evaluated. The conditions of chromatography were as follows: the separation was performed on a C18 column; the isocratic mobile phase consisted of acetonitrile and a mixed solution containing 10 mM sodium 1,2-naphthoquinone-4-sulfonate and 0.4 mM sodium 1-heptanesulfonate (25 + 75, v/v); and the flow rate was 1 mL/min. The fluorescence detector was set at an excitation wavelength of 263 nm and an emission wavelength of 435 nm. The calibration curve was linear over the range of 50–2000 ng/mL, with a correlation coefficient of 0.9995. The LOD and LOQ were 10 and 30 ng/g, respectively, in both cucumber and Chinese cabbage. The method was validated for selectivity, linearity, precision, and accuracy. The intraday and interday precision and accuracy were within 10%. The mean recoveries from spiked samples were more than 75%, with RSD lower than 10%.
Impact of the Analytical Blank in the Uncertainty Evaluation of the Copper Content in Waters by Flame Atomic Absorption Spectrometry
Authors: de Oliveira Elcio Cruz , Monteiro Maria Inês Couto , Pontes Fernanda Veronesi Marinho , Almeida Marcelo Dominguez de , Carneiro Manuel Castro , da Silva Lílian Irene Dias , Neto Arnaldo Alcover
Published: April 2012

Chemical analysts use analytical blanks in their analyses, but seldom is this source of uncertainty evaluated. Generally, there is great confusion. Although the numerical value of the blank, in some situations, can be negligible, its source of uncertainty cannot be. This article discusses the uncertainty contribution of the analytical blank using a numerical example of the copper content in waters by flame atomic absorption spectrometry. The results indicate that the uncertainties of the analytical blank can contribute up to 50% when the blank sample is considered in this analysis, confirming its high impact. This effect can be primarily observed where the analyte concentration approaches the lower range of the analytical curve. Even so, the blank is not always computed. Therefore, the relevance of the analytical blank can be confirmed by uncertainty evaluation.
Study of High-Resolution Mass Spectrometry Technology as a Replacement for Tandem Mass Spectrometry in the Field of Quantitative Pesticide Residue Analysis
Authors: Kaufmann Anton , Dvorak Veronika , Crüzer Claudio , Butcher Patrick , Maden Kathryn , Walker Stephan , Widmer Mirjam , Schürmann Andreas
Published: April 2012

A validated LC/MS/MS-based multiresidue pesticide method was converted to an LC high-resolution MS single-stage Orbitrap platform. No changes regarding the cleanup and LC were made. Optimization of high-resolution MS-specific parameters and interface settings was kept at a minimum. The aim was to explore the capability of current Orbitrap technology to substitute for LC/MS/MS technology. The test included the quantitative performance (sensitivity, selectivity, linearity, accuracy, and precision) of some 240 analytes in three different matrixes. The LC/MS/MS instrumentation was operated at the edge of its technical limitations. A further extension of the number of analytes for LC/MS/MS would require the use of even narrower dwell times, significantly reducing sensitivity and reproducibility of measurement. No such limitations exist for the high-resolution technology. Similar performance was observed for both technologies. A current drawback of the high-resolution technology is the speed of data processing, which took significantly longer than for LC/MS/MS data due to the limited capabilities of the software.
Method for the Determination of Catechin and Epicatechin Enantiomers in Cocoa-Based Ingredients and Products by High-Performance Liquid Chromatography: Single-Laboratory Validation
Authors: Machonis Philip R , Jones Matthew A , Schaneberg Brian T , Kwik-Uribe Catherine L
Published: April 2012

A single-laboratory validation study was performed for an HPLC method to identify and quantify the flavanol enantiomers (+)- and (–)-epicatechin and (+)- and (–)-catechin in cocoa-based ingredients and products. These compounds were eluted isocratically with an ammonium acetate–methanol mobile phase applied to a modified β-cyclodextrin chiral stationary phase and detected using fluorescence. Spike recovery experiments using appropriate matrix blanks, along with cocoa extract, cocoa powder, and dark chocolate, were used to evaluate accuracy, repeatability, specificity, LOD, LOQ, and linearity of the method as performed by a single analyst on multiple days. In all samples analyzed, (–)-epicatechin was the predominant flavanol and represented 68–91% of the total monomeric flavanols detected. For the cocoa-based products, within-day (intraday) precision for (–)-epicatechin was between 1.46–3.22%, for (+)-catechin between 3.66–6.90%, and for (–)-catechin between 1.69–6.89%; (+)-epicatechin was not detected in these samples. Recoveries for the three sample types investigated ranged from 82.2 to 102.1% at the 50% spiking level, 83.7 to 102.0% at the 100% spiking level, and 80.4 to 101.1% at the 200% spiking level. Based on performance results, this method may be suitable for routine laboratory use in analysis of cocoa-based ingredients and products.
Determination of Folate in Infant Formula and Adult/Pediatric Nutritional Formula by Optical Biosensor Assay: First Action 2011.05
Authors: Fonterra Harvey Indyk , Dowell Dawn
Published: April 2012

After a review of data from a single-laboratory validation (SLV) study published in the International Dairy Journal 21, 783–789 (2011), a method for folate in infant formula and adult/pediatric nutritional formula was submitted for consideration of adoption by AOAC as an automated assay that is rapid and simple. The method uses an optical biosensor assay to quantitate total folate content in milk and milk-based pediatric and adult nutritional products. The assay uses folate binding protein and a functionalized sensor surface. The SLV showed an instrumental LOD of 0.1 ng/mL (equivalent to 2.5 μg/100 g for a typical infant formula). The method detection limit was 6.5 μg/100 g with a repeatability of 3.48% and an intermediate reproducibility of 4.63% RSD.
Determination of Vitamin A in Infant Formula and Adult Nutritionals by UPLC-UV: First Action 2011.07
Authors: Trisconi Marie-José , Campos-Gimenez Esther , Audzems G Regj , Owell Awn
Published: April 2012

Vitamin A, a fat-soluble vitamin, is essential for health and plays an important part in vision, bone growth, reproduction, regulating the immune system, cell function, and skin health. Due to the advances in technology and the expansion of its uses, LC technologies are being studied for effectiveness in detecting and quantifying vitamin A in an effort to help determine the amount of vitamin A in various types of samples. For this reason, an Expert Review Panel agreed on June 29, 2011, at the “Standards Development and International Harmonization: AOAC INTERNATIONAL Mid-Year Meeting,” to approve “Determination of Vitamin A in Infant Formula and Adult Nutritionals by UPLC-UV” as AOAC Official MethodSM 2011.07. To move from First to Final Action status, it was recommended that additional information be generated for all types of infant formulas and adult nutritional formula matrixes at varied concentration levels, as indicated in the standard method performance requirements. International units or retinol equivalents typically represent the concentration of vitamin A in food and supplements. However, for the purpose of this method, the concentration represented is presented in μg/100 g.
Application of Ultra-High-Performance Liquid Chromatography/ Tandem Mass Spectrometry for the Measurement of Vitamin D in Infant Formula and Adult/Pediatric Nutritional Formula: First Action 2011.11
Authors: Huang Min , Winters Doug , Sullivan Darryl , Dowell Dawn
Published: April 2012

In an effort to measure vitamin D, ultra-high- performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) was applied to samples. The use of UHPLC-MS/MS decreased the run time by 50%. The UHPLC-MS/MS achieved equal or better separation efficiency with complex food matrixes compared to HPLC-MS/MS. It was also observed that under the optimized conditions of UHPLC, all previtamins of vitamin D3, D2, and isotope-labeled vitamin D3 were baseline- separated from their corresponding vitamins. The sterol isomers found in complex food matrixes that interfere in the analysis were well separated from the analytes. The accuracy of the method was evaluated by analyzing National Institute of Standards and Technology Standard Reference Material 1849 infant reference material. The average vitamin D3 concentration was 0.251 ± 0.012 μg/g. This showed excellent agreement with the certified value of 0.251 ± 0.027 μg/g. The spike recovery study of a commercial infant formula matrix showed a range of recovery from 100 to 108%. The LOQ values determined were 0.0022 and 0.0028 μg/g for vitamins D3 and D2, respectively; LOD values were 0.00065 and 0.00083 μg/g for vitamins D3 and D2, respectively.
Determination of Vitamin A (Retinol) in Infant Formula and Adult Nutritionals by Liquid Chromatography: First Action 2011.15
Authors: DeVries Jonathan W , Silvera Karlene R , McSherry Elliot , Dowell Dawn
Published: April 2012

During the “Standards Development and International Harmonization: AOAC INTERNATIONAL Mid- Year Meeting,” held on June 29, 2011, an Expert Review Panel (ERP) reviewed the method for the “Determination of Vitamins A (Retinol) and E (alpha-Tocopherol) in Foods by Liquid Chromatography: Collaborative Study,” published by Jonathan W. DeVries and Karlene R. Silvera in J. AOAC Int. in 2002. After evaluation of the original validation data, an ERP agreed in June 2011 that the method meets standard method performance requirements (SMPRs) for vitamin A, as articulated by the Stakeholder Panel on Infant Formula and Adult Nutritionals. The ERP granted the method First Action status, applicable to determining vitamin A in ready-to-eat infant and adult nutritional formula. In an effort to achieve Final Action status, it was recommended that additional information be generated for different types of infant and adult nutritional formula matrixes at varied concentration levels as indicated in the vitamin A (retinol) SMPR. Existing AOAC LC methods are suited for specific vitamin A analytical applications. The original method differs from existing methods in that it can be used to assay samples in all nine sectors of the food matrix. One sector of the food matrix was powdered infant formula and gave support for the First Action approval for vitamin A in infant and adult nutritional formula. In this method, standards and test samples are saponified in basic ethanol–water solution, neutralized, and diluted, converting fats to fatty acids and retinol esters to retinol. Retinol is quantitated by an LC method, using UV detection at 313 or 328 nm for retinol. Vitamin concentration is calculated by comparison of the peak heights or peak areas of retinol in test samples with those of standards.
Gluten and Celiac Disease—An Immunological Perspective
Authors: Rallabhandi Prasad
Published: April 2012

Gluten, a complex protein group in wheat, rye, and barley, causes celiac disease (CD), an autoimmune enteropathy of the small intestine, in genetically susceptible individuals. CD affects about 1% of the general population and causes significant health problems. Adverse inflammatory reactions to gluten are mediated by inappropriate T-cell activation leading to severe damage of the gastrointestinal mucosa, causing atrophy of absorptive surface villi. Gluten peptides bind to the chemokine receptor, CXCR3, and induce release of zonulin, which mediates tight-junction disassembly and subsequent increase in intestinal permeability. Proinflammatory cytokine IL-15 also contributes to the pathology of CD, by driving the expansion of intra-epithelial lymphocytes that damage the epithelium and promote the onset of T-cell lymphomas. There is no cure or treatment for CD, except for avoiding dietary gluten. Current gluten thresholds for food labeling have been established based on the available analytical methods, which show variation in gluten detection and quantification. Also, the clinical heterogeneity of celiac patients poses difficulty in defining clinically acceptable gluten thresholds in gluten-free foods. Presently, there is no bioassay available to measure gluten-induced immunobiological responses. This review focuses on various aspects of CD, and the importance of gluten thresholds and reference material from an immunological perspective.
Immunoreactivity and Detection of Wheat Proteins by Commercial ELISA Kits
Authors: Sharma Girdhari M
Published: April 2012

Wheat proteins are responsible for sensitivities, including baker's asthma, immunoglobulin E (IgE)-mediated allergic reaction, wheat-dependent, exercise-induced anaphylaxis, and celiac disease. The detection of gluten/wheat traces in foods is important to safeguard the health of wheat-sensitive individuals and comply with food labeling. Many immunoanalytical-based commercial kits are available for the quantification of gliadin/gluten/wheat proteins. We compared the immunoreactivity of wheat fractions with wheat-allergic human serum IgE and antibody conjugates used in six commercial immunoassay kits. Moreover, the performance of the kits was tested using corn flour spiked with gluten (5, 10, 25, and 50 ppm) and wheat flour (50, 100, 250, and 500 ppm). The albumin, globulin, gliadin, and glutenin fractions reacted with IgE from nine, eight, two, and eight patients' sera, respectively, out of nine wheat allergic patients tested. Among the antibodies from commercial kits, those from R-Biopharm, Morinaga, and Romer Labs reacted strongly with the gliadin fraction, whereas those from BioKits, ALLERTEK, and ELISA Systems reacted strongly with the glutenin fraction. All kits showed minimal or no reactivity with albumin and globulin fractions. All kits detected the gluten and wheat flour in a corn flour matrix at the lowest spiked levels of 5 and 50 ppm, respectively. However, there was wide variation among the kits when comparing the recovery of gluten and wheat flour. The recovery was also dependent on the source material (gluten or wheat flour) used for spiking the corn flour matrix.
Detoxification of Gluten by Means of Enzymatic Treatment
Authors: Wieser Herbert , Koehler Peter
Published: April 2012

Celiac disease (CD) is an inflammatory disease of the upper small intestine in genetically predisposed individuals caused by glutamine- and proline-rich peptides from cereal storage proteins (gluten) with a minimal length of nine amino acids. Such peptides are insufficiently degraded by gastrointestinal enzymes; they permeate the lymphatic tissue, are bound to celiac-specific, antigen-presenting cells, and stimulate intestinal T-cells. The typical clinical pattern is a flat small intestinal mucosa and malabsorption. Currently, the only therapy is a strict, lifelong gluten-free diet. Recent research has shown that gluten and gluten peptides can be degraded by prolyl endopeptidases from different sources. These peptidases can either be used to produce gluten-free foods from gluten-containing raw materials, or they have been suggested as an oral therapy for CD, in which dietary gluten is hydrolyzed by coingested peptidases already in the stomach, thus preventing CD-specific immune reactions in the small intestine. This would be an alternative for CD patients to the gluten-free diet. Furthermore, microbial transglutaminase could be used to detoxify gluten either by selectively modifying glutamine residues of intact gluten by transamidation with lysine methyl ester or by crosslinking gluten peptides in beverages via isopeptide bonds so that they can be removed by filtration.
A River Runs through Math Class
Authors: Cooper Linda L. , Roberge Martin C.
Published: April 2012

Let's go wading! Students connect fundamental mathematics concepts in this real-world, problem-solving field experience.
Optimization: Old Dogs and New Tasks
Authors: Kaplan Jennifer J. , Otten Samuel
Published: April 2012

An optimization problem from a calculus class can be made accessible to algebra and prealgebra students. Are you smarter than a Welsh corgi?
Helping Students Become Quantitatively Literate
Authors: Piatek-Jimenez Katrina , Marcinek Tibor , Phelps Christine M. , Dias Ana
Published: April 2012

How teaching for QL differs from teaching a traditional mathematics course and where to find good QL problems.
Activities for Students: Delivered Tomorrow: Plane and Truck Geometry
Authors: Poehl Terrie T.
Published: April 2012

Voronoi diagrams, graph theory, and geography are used to explain and demonstrate sample ground and air transportation networks.
Borax‐Mediated Formation of Carbon Aerogels from Glucose
Authors: Fellinger Tim‐Patrick , White Robin J. , Titirici Maria‐Magdalena , Antonietti Markus
Published: April 2012

Hierarchically structured carbon aerogels are produced in a simple, rapid, efficient, and sustainable hydrothermal approach, using only glucose as the carbon precursor. Using sodium borate (borax) as a novel complex structure directing agent nanostructured, carbon monoliths, structurally similar to the well‐known sol‐gel monoliths made of silica are obtained. Experimental results indicate the acetalization reaction of monosaccharides with their dehydration product hydroxymethylfurfural to be very important and inhibiting in the process of hydrothermal carbonization. Addition of borax, leads to a competitive complexation of diols, resulting in promising secondary catalytic effect with regard to carbon yield. Accordingly, it is shown that the sugar:borax ratio directs the primary carbon nanoparticle size into the sub −50 nm range, while their spinodal destabilization ultimately results in the controlled aggregation of carbonaceous particles leading to the formation of monoliths in a simple one step hydrothermal process. Post‐synthesis thermal carbonization is also used to increase surface area to the medium‐high range, introducing electric conductivity into the carbon monoliths. The resulting materials are promising candidates for applications in flash chromatography, for fast adsorption/purifications, and as porous conductive electrodes.
Biomimetic Design of Protein Nanomaterials for Hydrophobic Molecular Transport
Authors: Ren Dongmei , Dalmau Mercè , Randall Arlo , Shindel Matthew M. , Baldi Pierre , Wang Szu‐Wen
Published: April 2012

Biomaterials such as self‐assembling biological complexes have a variety of applications in materials science and nanotechnology. The functionality of protein‐based materials, however, is often limited by the absence or locations of specific chemical conjugation sites. Here a new strategy is developed for loading organic molecules into the hollow cavity of a protein nanoparticle that relies only on non‐covalent interactions, and its applicability in drug delivery is demonstrated in breast cancer cells. Based on a biomimetic model that incorporates multiple phenylalanines to create a generalized binding site, the anti‐tumor compound doxorubicin is retained and delivered by redesigning a caged protein scaffold. Using structural modeling and protein engineering, variants of the E2 subunit of pyruvate dehydrogenase with varying levels of drug‐carrying capabilities are obtained. An increasing number of introduced phenylalanines within the scaffold cavity generally results in greater drug loading capacity. Drug loading levels greater than conventional nanoparticle delivery systems are achieved. The universal strategy can be used to design de novo hydrophobic binding domains within protein‐based scaffolds for molecular encapsulation and transport and increases the ability to attach guest molecules to this class of materials.
Selective Enhancement of Photoluminescence in Filled Single‐Walled Carbon Nanotubes
Authors: Liu Xianjie , Kuzmany Hans , Ayala Paola , Calvaresi Matteo , Zerbetto Francesco , Pichler Thomas
Published: April 2012

The insertion of organometallic molecules into the hollow core of single‐walled carbon nanotubes can drastically change their properties. Using biocompatible standardized suspensions of pristine, opened, and filled nanotubes, a very selective enhancement of the photoluminescence and optical absorption is observed. Via ferrocene encapsulation, the PL signal increases almost by a factor of three for tubes with chiralities such as (8,6) and (9,5). This behavior is attributed to a local electron charge transfer from the ferrocene molecules that balances out the p‐type doping of the nanotubes resulting from the modified charge distribution of the surfactant molecules and the opening process. The near infrared photoluminescence of the nanotubes in solution is strongly enhanced when ferrocene is encapsulated. The diameter‐dependent charge transfer is additionally confirmed by first principles calculations. These findings highlight an essential ingredient to optimize the application of solvated nanotubes, for instance, as in–vivo near infrared sensors in biomedical research.
Heteroatom‐Modulated Switching of Photocatalytic Hydrogen and Oxygen Evolution Preferences of Anatase TiO2 Microspheres
Authors: Liu Gang , Pan Jian , Yin Lichang , Irvine John TS , Li Feng , Tan Jun , Wormald Philip , Cheng Hui‐Ming
Published: April 2012

Understanding and manipulating the two half‐reactions of photoinduced electron reduction and hole oxidation are key to designing and constructing efficient photocatalysts. Here, how the spatial distribution of the heteroatom modulates photocatalytic reduction (hydrogen evolution) and oxidation (oxygen evolution) reaction preferences is investigated by moving boron from the core to the shell of an anatase TiO2 microsphere along [001] via thermal diffusion control. The preference towards photocatalytic hydrogen and oxygen producing reactions from splitting water can be switched by creating a shell with an interstitial Bσ+ (σ ≤ 3) gradient in the TiO2 microsphere. This switching stems from the downward shift of electronic band edges of the shell by a band bending effect that originates from the extra electrons coming from the interstitial Bσ+. These results create new opportunities for designing and constructing efficient photocatalysts by spatial heteroatom engineering.
Honeycomb Structures of Bulk Metallic Glasses
Authors: Sarac Baran , Ketkaew Jittisa , Popnoe Dawn Olivia , Schroers Jan
Published: April 2012

A combination of lithography and thermoplastic forming allows us to fabricate honeycombs from bulk metallic glass (BMG) precisely and to manipulate its structure selectively. Characteristics of the honeycomb such as the ligament length, thickness, and radius of curvature at the joints of the cells are varied to determine how changes in these characteristics affect properties under uniaxial in‐plane compression testing. It is found that the deformation behavior of BMG honeycombs can be controlled through microstructural design, from brittle to ductile, by changing the length to thickness ratio of the ligaments. The ability to absorb energy of BMG honeycombs exceeds honeycombs of most other materials due to the utilization of a size effect, which result in plasticity. Besides the usage for BMG honeycombs, the technique provides a general method to effectively characterize complex microstructural architectures and tailoring these architectures to the specifications of the material used.
Evaluation of USDA Interval Forecasts Revisited: Asymmetry and Accuracy of Corn, Soybean, and Wheat Prices
Authors: Isengildina‐Massa Olga , Sharp Julia L.
Published: April 2012

This study evaluates the accuracy of the United States Department of Agriculture (USDA) interval forecasts for corn, soybean, and wheat prices using Christoffersen's (1998) tests for unconditional coverage, independence, and conditional coverage adjusted for asymmetries in tail probabilities. The findings demonstrate that due to the uneven distribution of forecast misses around the intervals, calibration of several corn, soybean, and wheat price forecasts was rejected by basic coverage tests (suitable for symmetric intervals), but not rejected by the tests adjusted for asymmetry. Thus, these forecasts were asymmetric, but accurate. USDA analysts should consider accounting for asymmetry and volatility of the underlying prices in their forecasts. [EconLit Citations: E370, Q110, C120].
Spatial Competition and Ethanol Plant Location Decisions
Authors: Sarmiento Camilo , Wilson William W. , Dahl Bruce
Published: April 2012

Ethanol is one of the fastest growing industries in the United States. This study estimates factors that impact location decisions for new ethanol plants using logistic regression analysis and spatial correlation techniques. The results indicate that location decisions are impacted by county agricultural characteristics, competing ethanol plants, and state‐level subsidies. Spatial competition is particularly important. Existence of competing ethanol plants reduces the likelihood of making a positive location decision, and this impact decreases with distance. Finally, state‐level subsidies are significant and a very important variable impacting ethanol location decisions. [JEL Classification: C13, C21, C25, C35, Q42]
Microdroplet coalescences at microchannel junctions with different collision angles
Authors: Wang Kai , Lu Yangcheng , Yang Lu , Luo Guangsheng
Published: April 2012

Microdroplet coalescence mechanism is very important for the miniaturization of multiphase chemical processes with microstructured devices. Using three working systems with different physical properties, this article presents an experimental study on the fluid dynamics of microdroplet coalescence at different microchannel junctions. The critical capillary number to distinguish coalescence or noncoalescence of microdroplet is investigated and its variations with droplet size, collision angle, and physical properties are analyzed with two important parameters – the film drainage time and droplet contact time. Experimental results indicate that microdroplet coalescence can be enhanced by reducing the droplet collision angle. The differences of microdroplet coalescences in confined microchannels and free‐flowing spaces are provided with the analysis of critical capillary number. A model equation is proposed to predict the critical capillary numbers in this study, which may provide valuable information for the design and development of new microstructured chemical device. © 2012 American Institute of Chemical Engineers AIChE J, 59: 643–649, 2013
Simplified gyral pattern with cerebellar hypoplasia in Sedaghatian type spondylometaphyseal dysplasia: A clinical report and review of the literature
Authors: Aygun Canan , Celik Fatma Cakmak , Nural Mehmet Selim , Azak Emine , Kucukoduk Şukru , Ogur Gonul , Incesu Lutfi
Published: April 2012

We report on a patient with Sedaghatian type spondylometaphyseal dysplasia (SSMD) who presented with metaphyseal dysplasia, congenital atrioventricular block, simplified gyral pattern, hypogenesis of corpus callosum, and severe cerebellar hypoplasia. We want to emphasize that in this rare congenital lethal skeletal dysplasia with unknown etiology, central nervous system malformations might be a major component of the disorder and should be evaluated in detail to possibly uncover the underlying pathophysiology. © 2012 Wiley Periodicals, Inc.
Complex genomic rearrangement in the SOX9 5′ region in a patient with Pierre Robin sequence and hypoplastic left scapula
Authors: Fukami Maki , Tsuchiya Takayoshi , Takada Shuji , Kanbara Akiko , Asahara Hiroshi , Igarashi Arisa , Kamiyama Yasunori , Nishimura Gen , Ogata Tsutomu
Published: April 2012

Pierre Robin sequence (PRS) can occur as a component of campomelic dysplasia (CD) and acampomelic CD (ACD) caused by dysfunction or dysregulation of SOX9, although it can also take place as an isolated form. Recently, genomic alterations in the far upstream and the far downstream region of SOX9 have been identified in patients with isolated PRS. Here, we report on a male patient with PRS and a heterozygous genomic rearrangement in the 5′ region of SOX9. Clinical analysis revealed PRS‐compatible craniofacial anomalies, mild hypoplasia of the left scapula, and normal male external genitalia. Molecular analysis identified a paracentric inversion on the long arm of chromosome 17 with breakpoints at 17q21.31 and 17q24.3, and a microdeletion spanning from −4.15 to −1.16 Mb relative to SOX9. These findings indicate that the chromosomal region more than 1.16 Mb apart from SOX9 contains at least one developmental enhancer(s) for SOX9 that plays a critical role in the development of the mandible and a relatively small role in the development of the scapula. Moreover, the concept of exclusion mapping argues that putative CD/ACD loci are located within the 1.16 Mb region closest to SOX9 coding exons, which remain intact in this Non‐CD/ACD patient. This study provides a novel example for long‐range cis‐regulatory mutations of SOX9. © 2012 Wiley Periodicals, Inc.
Rare copy number variants in isolated sporadic and syndromic atrioventricular septal defects
Authors: Priest James R. , Girirajan Santhosh , Vu Tiffany H. , Olson Aaron , Eichler Evan E. , Portman Michael A.
Published: April 2012

Atrioventricular septal defects (AVSDs) are a frequent but not universal component of Down syndrome (DS), while AVSDs in otherwise normal individuals have no well‐defined genetic basis. The contribution of copy number variation (CNV) to specific congenital heart disease (CHD) phenotypes including AVSD is unknown. We hypothesized that de novo CNVs on chromosome 21 might cause isolated sporadic AVSDs, and separately that CNVs throughout the genome might constitute an additional genetic risk factor for AVSD in patients with DS. We utilized a custom oligonucleotide arrays targeted to CNV hotspots that are flanked by large duplicated segments of high sequence identity. We assayed 29 euploid and 50 DS individuals with AVSD, and compared to general population controls. In patients with isolated‐sporadic AVSD we identified two large unique deletions outside of chromosome 21 not seen in the expanded set of 8,635 controls, each overlapping with larger deletions associated with similar CHD reported in the DECIPHER database. There was a small duplication in one patient with DS and AVSD. We conclude that isolated sporadic AVSDs may be occasionally associated with large de novo genomic structural variation outside of chromosome 21. The absence of CNVs on chromosome 21 in patients with isolated sporadic AVSD suggests that sub‐chromosomal duplications or deletions of greater than 150 kbp on chromosome 21 do not cause sporadic AVSDs. Large CNVs do not appear to be an additive risk factor for AVSD in the DS population. © 2012 Wiley Periodicals, Inc.
Noonan syndrome due to a SHOC2 mutation presenting with fetal distress and fatal hypertrophic cardiomyopathy in a premature infant
Authors: Hoban Rebecca , Roberts Amy E. , Demmer Laurie , Jethva Reena , Shephard Barbara
Published: April 2012

We report on a patient with Noonan syndrome due to SHOC2 missense mutation predicting p.Ser2Gly, recently described in association with Noonan syndrome. The male infant presented with fetal distress requiring premature delivery at 32 weeks and was noted to have dysmorphic features, edema, hepatosplenomegaly, leukocytosis, thrombocytopenia, and respiratory distress following birth. An echocardiogram revealed hypertrophic cardiomyopathy with left ventricular outflow tract obstruction. The infant's cardiac lesion rapidly progressed, and he was discharged home for palliative care. Clinical testing of genes causative of Noonan syndrome and related disorders detected the previously reported, pathogenic, de novo SHOC2 missense mutation predicting p.Ser2Gly. The patient's cardiac findings and features were not typical for those individuals previously reported with this SHOC2 mutation and thus expand the clinical phenotype. © 2012 Wiley Periodicals, Inc.
The incidence of hypoplasia of the corpus callosum in patients with dup (X)(q28) involving MECP2 is associated with the location of distal breakpoints
Authors: Honda Shozo , Hayashi Shin , Nakane Takaya , Imoto Issei , Kurosawa Kenji , Mizuno Seiji , Okamoto Nobuhiko , Kato Mitsuhiro , Yoshihashi Hiroshi , Kubota Takeo , Nakagawa Eiji , Goto Yu‐ichi , Inazawa Johji
Published: April 2012

Duplications of Xq28 harboring the methyl CpG binding protein 2 (MECP2) gene explain approximately 1% of X‐linked intellectual disability (XLID). The common clinical features observed in patients with dup(X)(q28) are severe ID, infantile hypotonia, mild dysmorphic features and a history of recurrent infections, and MECP2 duplication syndrome is now recognized as a clinical entity. While some patients with this syndrome have other characteristic phenotypes, the reason for the spectrum of phenotypes has not been clarified. Since dup(X)(q28) rearrangements vary in size and location, genes other than MECP2 might affect the phenotype. We used a high‐density oligonucleotide array to carry out precise mapping in eight Japanese families in which dup(X)(q28) was detected using an in‐house bacterial artificial chromosome‐based microarray to screen cohorts of individuals with multiple congenital anomalies and intellectual disability (MCA/ID) or with XLID. We hypothesized that the size, gene content, and location of dup(X)(q28) may contribute to variable expressively observed in MECP2 duplication syndrome. Genotype–phenotype correlation in our cases together with cases reported in the literature suggested that copy‐number gains between two low copy repeats (LCRK1 and LCRL1) are associated with the incidence of hypoplasia of the corpus callosum. Further studies are necessary to understand the mechanism of this association. © 2012 Wiley Periodicals, Inc.
Engineering glyceraldehyde‐3‐phosphate dehydrogenase for switching control of glycolysis in Escherichia coli
Authors: Cho Han‐Saem , Seo Sang Woo , Kim Young Mi , Jung Gyoo Yeol , Park Jong Moon
Published: April 2012

Glycolysis has evolved to be a highly robust mechanism for maintaining the cellular metabolism of living organisms. However, relevant modifications of glycolytic activity are required to intentionally modulate cellular phenotypes. Here, we designed a platform that allows switching control of glycolysis in Escherichia coli in response to an environmental signal, in this case, temperature. This system functions by regulating the expression of gapA, which encodes glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH), one of the key glycolytic enzymes. Because a very low level of gapA expression is capable of maintaining cellular physiology, we also modified GAPDH through directed evolution to provide sensitive regulation of glycolytic activity. The switching control of glycolysis was successfully demonstrated by regulating the expression of engineered gapA through changes in temperature. This system offers potential control over the cell's central carbon‐metabolism switch, providing the ability to perform reprogrammed tasks with desired timing depending on environmental signals. Biotechnol. Bioeng. 2012; 109: 2612–2619. © 2012 Wiley Periodicals, Inc.
Technological Aspects of Nanoemulsion Formation of Low‐Fat Foods Enriched with Vitamin E by High‐Pressure Homogenization
Authors: El Kinawy O. S. , Petersen S. , Ulrich J.
Published: April 2012

Formation of a low‐fat oil‐in‐water (O/W) nanoemulsion enriched with vitamin E using the nonionic surfactant Tween 40 is studied by means of a high‐pressure homogenizer. The effect of different process variables of the emulsification process, including pressure, temperature, and concentration of the emulsifying agent, is evaluated. The relation between pressure and the obtained mean droplet diameter is derived and described by an equation which can be taken as a basis of any process design. The droplet size can be decreased by increasing the vitamin E concentration. A higher fat content slightly affects the droplet size distribution and the mean droplet diameter of the nanoemulsion, so it is recommended to use preparations of nanoemulsions with low fat contents enriched with vitamin E for dietary supplement.
Synthesis Gas Production Configurations for Gas‐to‐Liquid Applications
Authors: Rafiee A. , Hillestad M.
Published: April 2012

Different syngas configurations in a gas‐to‐liquid plant are studied including autothermal reformer (ATR), combined reformer, and series arrangement of gas‐heated reformer and ATR. The Fischer‐Tropsch (FT) reactor is based on a cobalt catalyst and the degrees of freedom are steam‐to‐carbon ratio, purge ratio of light ends, amount of tail gas recycled to synthesis gas (syngas) and FT synthesis units, and reactor volume. The production rate of liquid hydrocarbons is maximized for each syngas configuration. Installing a steam methane reformer in front of an ATR will reduce the total oxygen consumption per barrel of product by 40 % compared to the process with only an ATR. The production rate of liquid hydrocarbons is increased by 25.3 % since the flow rate of the purge stream for the ATR is the highest one compared to other configurations and contains mainly CO2.