bluuebunny/crossref_metadata_2025 huggingface dataset:
Small‐angle optical deflection from collinear configuration for sensitive detection in microfluidic systems
Authors: Yang Li , Li Xiangtang , Li Jing , Yuan Hongyan , Zhao Shulin , Xiao Dan
Published: July 2012

This paper describes a novel detection system based on small‐angle optical deflection from the collinear configuration of a microfluidic chip. In this system, the incident light beam was focused on the microchannel through the edge of a lens, resulting in a small deflection angle that deviated 20° from the collinear configuration. The emitted fluorescence was collected through the center of the same lens and delivered to a photomultiplier tube in the vertical direction; the reflection light of the chip plate was kept away from the detector. In contrast to traditional confocal and nonconfocal laser‐induced fluorescence detection systems, background levels resulting from scattered excitation light, reflection and refraction from the microchip was significantly eliminated. Significant enhancement of the signal‐to‐noise ratio was obtained by shaping a laser beam that combined an attenuator with a spectral filter to optimize laser power and the dimensions of the laser beam. FITC and FITC‐labeled amino acid were used as model analytes to demonstrate the performance sensitivity, separation efficiency, and reproducibility of this detection system by using a hybrid polydimethylsiloxane/glass microfluidic device. The limit of detection of FITC was estimated to be 2 pM (0.55 zmol) (S/N = 3). Furthermore, the single cell analysis for the determination of intracellular glutathione in a single 3T3 mouse fibroblast cell was demonstrated. The results suggest that the proposed optical arrangements will be promising for development of sensitive, low‐cost microfluidic systems.
Determination of quinolones in milk samples using a combination of magnetic solid‐phase extraction and capillary electrophoresis
Authors: Ibarra Israel S. , Rodriguez Jose A. , Páez‐Hernández Ma. Elena , Santos Eva M. , Miranda Jose M.
Published: July 2012

A magnetic solid‐phase extraction (MSPE) method combined with capillary electrophoresis for the simultaneous determination of seven quinolones (QNs) (danofloxacin, ciprofloxacin, marbofloxacin, enrofloxacin, difloxacin, oxolinic acid, and flumequine), using (S)‐(+)‐6‐methoxy‐α‐methyl‐2‐naphthaleneacetic acid as internal standard, in milk samples was developed. The variables involved in the preconcentration magnetic procedure were: the composition of the magnetic support composition, the sample pH, and the weight of magnetic adsorbent used. The variables were optimized using a simplex‐lattice design. Different magnetite covered with octyl‐phenyl silica adsorbents were synthesized by varying the molar ratio of phenyltrimethylsilane and octyltrimethoxysilane; the solids were evaluated for QN preconcentration. Under optimal conditions, a linear range was obtained from 27 to 1000 μg L−1 with limits of detection ranging from 9 to 12 μg L−1 for the seven QNs. The absolute recoveries of the seven QNs at three different spiked levels (40, 150, and 400 μg L−1) ranged from 74% to 98% with a relative standard deviation less than 10% in all cases. The proposed method was applied to analyze 20 whole milk samples of different brands. All samples were positive for the presence of QN residues; in some cases, extract dilution was required. The concentrations found are in the range from 31.1 to 5047.3 μg L−1. Marbofloxacin was the most frequently found. The method proposed offers advantages in terms of simplicity, sensitivity, efficiency, cost, and analysis time making it an alternative for the analysis of QNs in whole milk samples.
Electrokinetic concentration and patterning of colloids with a scanning laser
Authors: Velasco Vanessa , Work Andrew H. , Williams Stuart J.
Published: July 2012

Optically‐based lab‐on‐a‐chip systems have the distinct advantage of being dynamically controlled in real time, providing reconfigurable operations that can be tuned to perform a variety of tasks. This manuscript demonstrates the concentration of liquid‐suspended microparticles using a focused near‐infrared laser (980 nm) and a parallel‐plate electrode system. The parallel‐plate electrodes consisted of an indium tin oxide‐coated coverslip and a gold‐coated glass substrate. When the laser was applied at 36 mW, the indium tin oxide surface is locally heated creating sharp temperature gradients on the order of 0.07oC/μm. When an AC field was applied, electrothermal hydrodynamic forces generated microfluidic vortices. At an AC frequency of 40 kHz, the optically controlled electro‐hydrodynamics aggregated colloids at the center of fluid motion on the surface of the indium tin oxide coverslip. The nature of colloid aggregation, translation, and patterning was explored when the translational velocity of the laser spot was varied. This manuscript describes the design of the laser scanning system using commercially available components and the fabrication of the parallel‐plate chip. The effect that the laser scanning rate has on the heat transfer, fluid velocity, and colloid aggregation is discussed.
Diamino moiety functionalized silica nanoparticles as pseudostationary phase in capillary electrochromatography separation of plant auxins
Authors: Li Hui , Ding Guo‐Sheng , Yue Chun-Yue , Tang An‐Na
Published: July 2012

A novel and simple method for the preparation of silica nanoparticles having surface‐functionalized diamino moiety (dASNPs) was reported in our paper and characterized using scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectrometry, and thermogravimetry techniques. To test this method practically, in this contribution we describe the enhanced separation of four plant auxins – indole‐3‐acetic acid (IAA), indole‐3‐butyric acid (IBA), 2,4‐dichlorophenoxyacetic acid (dCPAA), and 2‐(1‐naphthyl) acetic acid (NAA) – by capillary electrochromatography using diamino moiety functionalized silica nanoparticles as pseudostationary phase (PSP) in the running buffer. The effect of pH, buffer concentration, and diamino moiety functionalized silica nanoparticles concentration on the selectivity of separation was investigated. A combination of the nanoparticles and running buffer reversed the electroosmotic direction making possible the rapid and efficient separation of the auxins from the auxins migrated in the same direction with the EOF under optimum experimental conditions. A good resolution of four auxins was obtained within 5.5 min under optimum experimental conditions. The precision (RSD, n = 5) was in the range of 0.72–0.91% and 1.89–2.23% for migration time and peak area response, respectively. The detection limits were 0.48, 0.44, 0.46, and 0.42 μM for NAA, IBA, IAA, and dCPAA, respectively. Furthermore, the method was successfully tested for the determination of IAA in the grapes.
Studies on bioconjugation of quantum dots using capillary electrophoresis and fluorescence correlation spectroscopy
Authors: Wang Jinjie , Huang Xiangyi , Zan Feng , Guo Chen‐gang , Cao Chengxi , Ren Jicun
Published: July 2012

In this paper, we systematically investigated the conjugation of quantum dots (QDs) with certain biomolecules using capillary electrophoresis (CE) and fluorescence correlation spectroscopy (FCS) methods. Commercial QDs and aqueous‐synthesized QDs in our lab were used as labeling probes, certain bio‐macromolecules, such as proteins, antibodies, and enzymes, were used as mode samples, and 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide hydrochloride (EDC) and N‐hydroxysulfo‐succinimide (Sulfo‐NHS) were used as linking reagents. We studied the effects of certain factors such as the isoelectric points (pIs) of bio‐macromolecules and buffer pH on the bioconjugation of QDs, and found that the pIs of bio‐macromolecules played an important role in the conjugation reaction. By the optimization of the buffer pH some proteins with different pIs were efficiently conjugated with QDs using EDC and Sulfo‐NHS as linking agents. Furthermore, we on‐line investigated the kinetic process of QDs‐bioconjugation by FCS and found that the conjugation reaction of QDs with protein was rapid and the reaction process almost completed within 10 min. We also observed that QDs conjugated with proteins were stable for at least 5 days in phosphate buffer. Our work described here will be very helpful for the improvement of the QDs conjugation efficiency in bioapplications.
Separation and determination of chiral composition in penicillamine tablets by capillary electrophoresis in a broad pH range
Authors: Song Lijuan , Guo Zhenpeng , Chen Yi
Published: July 2012

A chiral capillary electrophoretic method with nearly full pH window was explored for the separation and determination of dl‐penicillamine. A facile one‐pot labeling technique was coupled in the method for introduction of chromophore and charge groups onto the analytes to facilitate the electromigration and sensitive detection. By using simply a cost‐effective neutral β‐cyclodextrin as chiral selector, baseline separation of the dl‐penicillamine was achieved from pH 2.0 to over pH 10. Quantification of standard d‐ and l‐penicillamines was demonstrated by taking pH 4.5, 7.4, and 9.7 as the representatives of acidic, neutral, and basic conditions. The working curves were constructed between peak area and concentration, having linear ranges of 8.56–8.56 × 102 μg/mL for pH 4.5 and 8.56–1.71 × 103 μg/mL for pH 7.4 and 9.7, with correlation coefficients all better than 0.999. The limit of detection (S/N = 3) was 2.58 μg/mL in acidic and neutral conditions or 1.41 μg/mL in basic condition. The method was further validated by assaying the commercial penicillamine tablets, applicable to quantification of the effective enantiomer and the trace impurity of l‐penicillamine at a content of down to 0.2, 0.6, and 2.0% for pH 9.7, 4.5, and 7.4, respectively. The recovery determined by spiking technique was in a range from 93.1 to 105 %. The method is easily extendable to the analysis of other chiral amines or amino acids.
Nitrogen‐ and Oxygen‐Enriched Carbon With Square Tubular Structure Prepared From Polyaniline as Electrode for Supercapacitors
Authors: Xiang X. , Liu E. , Wu Y. , Tian Y. , Xie H. , Wu Z. , Zhu Y.
Published: July 2012

Square tubular carbon with a large number of surface functional groups are prepared by carbonizing and activating polyaniline, which are synthesized by polymerization of aniline with a template‐free self‐assembly method in aqueous media. The physicochemical properties of the square tubular carbon is characterized by scanning and transmission electron microscopy, Brunauer–Emmett–Teller surface area measurements, Raman spectroscopy, and X‐ray photoelectron spectroscopy measurements. When used as an electrode, the square tubular carbon exhibit a specific capacitance of 223 F g–1 at a scan rate of 2 mV s–1, which could still stay over 90% when the scan rate increased by 10 times. The specific capacitance even hardly decrease at a current density of 3 A g–1 after 10,000 cycles, which indicates that the square tubular carbon have good cycle durability and may be a promising candidate as an electrode for supercapacitors.
Micro‐PIXE Geochemical Fingerprinting of Nephrite Neolithic Artifacts from Southwest Bulgaria
Authors: Kostov Ruslan I. , Protochristov Christo , Stoyanov Chavdar , Csedreki László , Simon Alíz , Szikszai Zita , Uzonyi Imre , Gaydarska Bisserka , Chapman John
Published: July 2012

Neolithic artifacts made of nephrite, □Ca2(Fe,Mg)5Si8O22(OH)2, are found at prehistoric settlements in Bulgaria. This study investigates these objects based on particle induced X‐ray emission using a scanning nuclear microprobe (micro‐PIXE technique). Seven nephrite artifacts from the Neolithic sites of Kovachevo, Bulgarchevo and Galabnik in southwest Bulgaria were analyzed to quantify their composition and to establish if a correlation exists between the distribution of major and trace elements, color, impurities, and texture. The nephrite artifacts are tremolite in composition, with a proposed ultrabasic origin. Based on the geochemical data obtained by micro‐PIXE, we divide the artifacts into Group 1 objects from the Kovachevo site and Group 2 objects from the Galabnik and Bulgarchevo sites. The analytical data and microprobe analyses are compared with geochemical data of nephrite from across the globe. The results are in a good agreement with previous electron microprobe and electron paramagnetic resonance (EPR) spectroscopy data. Our study provides a better understanding of the mineralogy and geochemistry of nephrite artifacts and helps to address questions regarding origin and the distribution of such materials in Bulgaria and other Balkan countries.
Effective methods for preparation and characterization of HNO‐adducts of heme proteins
Authors: Czarnecki Kazimierz , Kincaid James R.
Published: July 2012

Driven by the documented effectiveness of cryoradiolysis coupled with resonance Raman spectroscopy for the preparation and structural characterization of unstable peroxo and hydroperoxo intermediates of catalytic and oxidative enzymes, similar strategies have now been applied to prepare and study the still relatively unexplored chemistry of nitrosyl hydride (HNO) adducts of heme proteins and their derivatives. Previously, such HNO derivatives of heme proteins were prepared by chemical addition of reducing agents or by direct addition of an HNO donor. Here, for the first time, we report effective cryoradiolytic preparation of Fe–N(H)O species of myoglobin and their structural characterization by resonance Raman spectroscopy. Our results are in excellent agreement with those previously reported for chemically prepared derivatives and with computational results. Furthermore, the present study provides new data for the deuterated analogue; i.e. bearing a nitrosyl deuteride (DNO) fragment. Copyright © 2012 John Wiley & Sons, Ltd.
Temperature‐dependent Raman spectroscopy study in MoO3 nanoribbons
Authors: Silveira Jose V. , Vieira Luciana L. , Filho Josue Mendes , Sampaio Antonio J. C. , Alves Oswaldo L. , Souza Filho Antonio G.
Published: July 2012

This paper reports a study of vibrational, structural and morphological properties of molybdenum oxide nanoribbons. Temperature‐dependent Raman spectroscopy measurements in MoO3 nanoribbons revealed morphological changes in the 150–350 °C temperature range. No structural phase transitions were observed, thus showing that the orthorhombic phase is stable from room temperature (nanoribbons) up to 650 °C (bulk‐like phase) where large plates have been formed by the coalescence of the nanoribbons. The interpretation of temperature‐dependent Raman data (wavenumber and linewidths) is supported by scanning electron microscopy that is used to directly probe the morphological changes in MoO3 samples. The observed phenomena in the Raman data for MoO3 nanoribbons can be applied to other nanomaterials. Copyright © 2012 John Wiley & Sons, Ltd.
Raman and fluorescence investigations on retrieved Biolox® delta femoral heads
Authors: Taddei Paola , Modena Enrico , Traina Francesco , Affatato Saverio
Published: July 2012

Since the introduction of ceramic‐on‐ceramic couplings in total hip arthroplasty, continuous efforts have been performed to improve the performance of the prosthetic components. To expand the applications of ceramics, in 2000 an innovative alumina–zirconia composite was introduced in the market. The present study represents the first investigation aimed at characterising at the molecular level Biolox® delta retrievals implanted between 1999 and 2009. Fluorescence and Raman results showed that a progressive improvement of the material properties has occurred in the period between 1999 and 2009. Raman spectroscopy showed that wear was the main cause of the in vivo tetragonal‐to‐monoclinic zirconia transformation. Our findings validated the in vitro accelerated ageing protocols proposed in the literature to simulate the effects of the in vivo wear, because the mechanism operating in vivo was found to be the same active in vitro. The in vitro fracture of a new femoral head appeared to be an extreme wear condition that determined the most significant changes in the residual stress state and monoclinic content both in the section of the fragments and on their surface. The micro‐Raman mapping of the fractured articulating surface showed that the tetragonal‐to‐monoclinic transformation involved a region much more extended than as reported in the literature. Copyright © 2012 John Wiley & Sons, Ltd.
Distinguishable behavior of multiple and individual rhodamine‐6G molecules on spherical Ag nanoparticles examined via time dependence of the SERS spectra
Authors: Luo Zhixun , Hunter Woodward W. , Castleman A. W.
Published: July 2012

We report a surface‐enhanced Raman spectroscopy (SERS) investigation to probe the adsorption and dynamic behavior of rhodamine 6 G (Rh6G) molecules on spherical Ag nanoparticles which were produced via laser ablation in liquid. Assembly of the colloidal Ag nanoparticles on a cover glass was used to work as SERS substrates on which high‐quality SERS spectra of Rh6G were obtained with interesting time dependence when using low and ultralow concentrations, respectively. The variation of SERS spectra over time was identified with the adsorption behavior of multiple and individual molecules on the Ag nanoparticles. Analysis indicates that the adsorbed Rh6G molecules can desorb away from the initial locations on the substrate under continuous laser excitation; simultaneously, some individual molecules can move and become trapped in the gap between the aggregated Ag nanoparticles. These investigations help to clarify the origins of forming ‘hot‐spots’ which host probe molecules and hence improve the understanding of mechanisms for single‐molecule SERS spectroscopy. Copyright © 2012 John Wiley & Sons, Ltd.
Raman investigation of artificial patinas on recent bronze‒part II: urban rain exposure
Authors: Kosec Tadeja , Ropret Polonca , Legat Andraž
Published: July 2012

Patinas form spontaneously on copper and high copper alloys when exposed to humidity and air. They usually protect the underlying metal from corrosion. Bronze is often chemically patinated by artists to achieve an antique appearance. However, in the case of chemical patinations on bronze, there is a lack of studies about their change over time during exposure to different types of environments.

Recent types of bronze, brown patina and two green type patinas (green chloride and green nitrate patina) applied over a brown patina, were selected for testing. The aim of the present study was to monitor the transformation process of chemically formed patinas and of the bronze itself after exposure to simulated urban acid rain, for a period of 35 days. The structures of the patina and corrosion products were characterized by scanning electron microscopy (SEM) and Raman spectroscopy.

Three differently coloured patinas were scraped off from the bronze statue of the poet France Prešeren, two green type patinas and one brown type, to predict the probable influences of the environment, the base alloy and previously used patination techniques. Copyright © 2012 John Wiley & Sons, Ltd.
Semiclassical line broadening calculations, using an ab initio potential energy surface, in Q‐branch and S‐branch of N2 perturbed by H2
Authors: Dhyne M. , Lepère M. , Joubert P.
Published: July 2012

In order to improve the accuracy of Raman combustion diagnostics, the broadening coefficients of N2 perturbed by H2 for Q‐branch and S‐branch have been calculated by the semiclassical Robert–Bonamy model using an ab initio potential energy surface. The calculations have been performed for a large range of temperatures (from 77 to 800 K) and J rotational quantum numbers (from 0 to 60). This paper shows that our results and their temperature dependence are in good agreement with earlier published experimental and theoretical data. Moreover, our results improve the semiclassical calculations made earlier with an adapted analytical potential. The results, obtained at high temperatures and for a large range of rotational quantum numbers, are presented in order to be implemented for optical diagnostics in combustion media. Copyright © 2012 John Wiley & Sons, Ltd.
Investigations Into Amphiphilic Chitosan: Properties and Availability of Original and Newly Introduced Functional Groups
Authors: Fasl Hubert , Zemljič Lidija Fras , Goessler Walter , Stana‐Kleinschek Karin , Ribitsch Volker
Published: July 2012

The accessibility of functional groups of 3,6‐O‐chitosansulfate in water is studied using conductometric and polyelectrolyte titration techniques. These studies reveal the good accessibility of protonated amino groups following conductometric titrations and pH dependency on the accessibility of negatively charged sulfate groups following polyelectrolyte titrations. In addition, the influence of negatively charged sulfate groups, introduced onto polymer backbone by synthesis, is analyzed regarding the well‐known antimicrobial activities of chitosan. The assessment of the mortality rates of Gram‐negative, Gram‐positive bacteria, and pathogenic fungi reveal that sulfate groups in chitosan lead to a tremendous loss in antimicrobial activity compared with nonmodified chitosan.
Oligoepoxide‐Based Monoliths: Synthesis and Application as Affinity Capillary Column for Enrichment of Immunoglobulin G
Authors: Pecher Heike S. , Zimathies Annett , Weller Michael G.
Published: July 2012

A series of new epoxide‐based monoliths is synthesized by self‐polymerization of polyglycerol polyglycidyl ether as porous support for affinity chromatography. Porosity and mean pore sizes are investigated as a function of the porogen ratio and analyzed by mercury porosimetry. The morphologies are visualized by environmental scanning electron microscope. With a particularly rigid monolith prepared with 75 vol% porogen (66% porosity and 12 μm mean pore size), a capillary column (0.5 mm ID) is prepared and directly functionalized with recombinant protein A to extract immunoglobulin G from rabbit serum.
Quality control of prostate 1 H MRSI data
Authors: Wright Alan J. , Kobus Thiele , Selnæs Kirsten M. , Gribbestad Ingrid S. , Weiland Elizabeth , Scheenen Tom W. J. , Heerschap Arend
Published: July 2012

MRSI of prostate cancer provides a potential clinical tool to aid in the detection and characterisation of this disease, but its clinical use is limited by the need for the specialist training of radiologists to read these datasets. An essential part of this reading is the assessment of the usability and reliability of MRSI spectra because they can be affected by artefacts such as poor signal to noise, lipid signal contamination and broad resonances that could cause errors of interpretation. We have developed an automated quality control algorithm that classifies every voxel of an MRSI dataset as either acceptable or unacceptable for further analysis, based on the spectral profile alone. The method was trained and tested based on a gold standard of agreement of four experts. It was highly accurate: testing with a novel set of data from MRSI patients produced agreement with the experts' consensus decisions with a specificity of 0.95 and sensitivity of 0.95. This method provides fast quality control of three‐dimensional MRSI datasets of the prostate, removing the need for radiologists to perform this time consuming, but necessary, task prior to further analysis. Copyright © 2012 John Wiley & Sons, Ltd.
Synthesis and characterization of the novel meta‐modified aramid fibers with liquid crystalline properties
Authors: Jin Hui , Wang Yiyong
Published: July 2012

To improve the interfacial adhesion between the meta‐aramid fibers and the matrix, the new method of interfacial polymerization was used to complete the aramid's surface modification. Two new kinds of grafted fibers which had liquid crystalline properties were prepared. The structure and properties of the aramid fibers before and after modification were characterized by scanning electron microscope (SEM), Fourier transform infrared, differential scanning calorimetry, and polarizing optical microscope. The surface of grafted aramid fibers was very rough. The range of liquid crystalline phase of the grafted fibers AF‐1 and AF‐2 on the cooling scan, respectively, is from 147 to 209°C and from 163 to 221°C. It was novel that the grafted fibers with rigid‐rod structure had typical nematic texture. The grafted aramid fibers as the ideal substitute material of asbestos were used as reinforcing fibers in nitrile butadiene rubber (NBR) matrix. Combining with NBR, the composites reinforced with the unmodified and grafted aramid fibers were synthesized. The micrographs of the composites' fractured surface were studied by SEM. The mechanical properties of the grafted fibers/NBR composites were superior to the unmodified fibers/NBR composites. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers
Risk of Guillain–Barré syndrome after meningococcal conjugate vaccination
Authors: Velentgas Priscilla , Amato Anthony A. , Bohn Rhonda L. , Arnold Chan K. , Cochrane Thomas , Funch Donnie P. , Dashevsky Inna , Duddy April L. , Gladowski Patricia , Greenberg Steven A. , Kramer Judith M. , McMahill‐Walraven Cheryl , Nakasato Cynthia , Spettell Claire M. , Syat Beth L. , Wahl Peter M. , Walker Alexander M. , Zhang Fang , Brown Jeffrey S. , Platt Richard
Published: July 2012

Purpose

A new meningococcal conjugate vaccine (MCV4) was introduced in 2005. Shortly after, case reports of Guillain–Barré syndrome (GBS), a serious demyelinating disease, began to be reported to the Vaccine Adverse Event Reporting System. In 2006, the Centers for Disease Control and Prevention and the Food and Drug Administration requested the evaluation of GBS risk after MCV4 vaccination. We conducted a study to assess the risk of GBS after MCV4 vaccination using health plan administrative and claims data together with the review of primary medical records of potential cases.

Methods

Retrospective cohort study among 12.6 million 11‐ to 21‐year‐old members of five US health plans with a total membership of 50 million. Automated enrollment and medical claims data from March 2005 through August 2008 were used to identify the population, the vaccinations administered, and the medical services associated with possible GBS. Medical records were reviewed and adjudicated by a neurologist panel to confirm cases of GBS. The study used distributed data analysis methods that minimized sharing of protected health information.

Results

We confirmed 99 GBS cases during 18,322,800 person‐years (5.4/1,000,000 person‐years). More than 1.4 million MCV4 vaccinations were observed. No confirmed cases of GBS occurred within 6 weeks after vaccination. The upper 95% CI for the attributable risk of GBS associated with MCV4 is estimated as 1.5 cases per 1,000,000 doses.

Conclusions

Among members of five US health plans, MCV4 vaccination was not associated with increased GBS risk. Copyright © 2012 John Wiley & Sons, Ltd.
New and improved proteomics technologies for understanding complex biological systems: Addressing a grand challenge in the life sciences
Authors: Hood Leroy E. , Omenn Gilbert S. , Moritz Robert L. , Aebersold Ruedi , Yamamoto Keith R. , Amos Michael , Hunter‐Cevera Jennie , Locascio Laurie ,   Workshop Participants
Published: July 2012

This White Paper sets out a Life Sciences Grand Challenge for Proteomics Technologies to enhance our understanding of complex biological systems, link genomes with phenotypes, and bring broad benefits to the biosciences and the US economy. The paper is based on a workshop hosted by the National Institute of Standards and Technology (NIST) in Gaithersburg, MD, 14–15 February 2011, with participants from many federal R&D agencies and research communities, under the aegis of the US National Science and Technology Council (NSTC). Opportunities are identified for a coordinated R&D effort to achieve major technology‐based goals and address societal challenges in health, agriculture, nutrition, energy, environment, national security, and economic development.
Validation of an Alternative Method for Testing the Chemical Compatibility of Liquids with Polyethylene Packagings for Dangerous Goods
Authors: Eiben Mario , Schmidt Anita , Menrad Andreas , Jahnke Wolfgang , Goedecke Thomas
Published: July 2012

Safety risks may ensue when the chemicals contained in polyethylene packagings age and damage them. To prevent subsequent accidents, the European Dangerous Goods Regulations have laid down requirements for testing the chemical compatibility of liquid dangerous goods transported in polyethylene packagings. The test procedures include 6 months in which the chemical is prestored in the packaging. After this time, the respective design‐type tests are performed. Alternative methods with so‐called standard liquids, simulating the different types of damaging effects, are also possible. If a packaging has successfully passed the design type tests with a standard liquid, other dangerous goods may also be transported in this packaging, as long as it is demonstrated that they have a less damaging effect than the standard liquid. However, in this area there is only little information and research available.

A new potentially effective and time‐saving method for comparing the stress crack damaging influence of liquids with standard liquids was proposed by a major German chemical company.

The validation of this method, which was carried out on two polyethylene materials, showed the general applicability of the method. Two kinds of wetting solutions were applied to simulate cracking under stress.

The influence of prestorage, test temperatures, wetting agents and material was examined. FEM calculations were carried out to ascertain the influence of the sample shape. Copyright © 2012 John Wiley & Sons, Ltd.
First in situ Optical Emission Spectroscopy measurements during cesium low‐energy depth profiling
Authors: Mine N. , Houssiau L.
Published: July 2012

Studying ex situ the fundamental processes involved during cesium low‐energy molecular depth profiling of polymers is a hard task owing to the well‐known cesium reactivity. Lately, we developed in‐situ Optical Emission Spectroscopy (OES) on our ToF‐SIMS IV instrument. Photons emitted from the sputtered area are monitored in the wavelength range 200 nm to 950 nm. Surprisingly, intense cesium atomic lines are detected throughout the depth profile of a polymer (polystyrene) deposited on a silicon substrate, at 852 nm and 894 nm. However, no optical signals were detected from 200 nm to 950 nm when xenon or oxygen primary ions were used to depth profile polymers. This efficient infrared channel of energy dissipation is unique to the cesium sputtering process. We assume it can play an important role in the way the local energy density is transferred to the material contrary to the use of other primary ions for sputtering. We will show that ToF‐SIMS and OES depth profiles can be recorded simultaneously. Finally, cesium–xenon cosputtering experiments on silicon will correlate the 852‐nm signal intensity to the cesium concentration in the primary ion beam. The importance of inelastic collisions and electron promotion leading to light emission is often shadowed in our understanding of the sputtering process. These experiments are a first insight of this fundamental process during cesium depth profiling. Copyright © 2012 John Wiley & Sons, Ltd.
Optimal screening schedules for prevention of metastatic cancer
Authors: Hanin Leonid , Pavlova Lyudmila
Published: July 2012

We develop methodological, mathematical, statistical, and computational approaches to constructing schedules of cancer screening that maximize the probability that by the time of primary tumor detection it has not yet metastasized. Solving this problem is based on a comprehensive mechanistic model of cancer progression. We apply the model with realistic parameters and the screening optimization methodology to mammographic screening for breast cancer within the American female population. We uncover some general patterns of optimal screening schedules. We show that optimization of screening regimens leads to a significant reduction in the probability of detecting breast cancer that has already disseminated. Copyright © 2012 John Wiley & Sons, Ltd.
A trivariate continual reassessment method for phase I/II trials of toxicity, efficacy, and surrogate efficacy
Authors: Zhong Wei , Koopmeiners Joseph S. , Carlin Bradley P.
Published: July 2012

Recently, many Bayesian methods have been developed for dose finding when simultaneously modeling both toxicity and efficacy outcomes in a blended phase I/II fashion. A further challenge arises when all the true efficacy data cannot be obtained quickly after the treatment so that surrogate markers are instead used (e.g., in cancer trials). We propose a framework to jointly model the probabilities of toxicity, efficacy, and surrogate efficacy given a particular dose. Our trivariate binary model is specified as a composition of two bivariate binary submodels. In particular, we extend the bivariate continual reassessment method (CRM), as well as utilize a particular Gumbel copula. The resulting trivariate algorithm utilizes all the available data at any given time point and can flexibly stop the trial early for either toxicity or efficacy. Our simulation studies demonstrate that our proposed method can successfully improve dosage targeting efficiency and guard against excess toxicity over a variety of true model settings and degrees of surrogacy. Copyright © 2012 John Wiley & Sons, Ltd.
Comparative effectiveness research: does one size fit all?
Authors: Kunz Lauren M. , Yeh Robert W. , Normand Sharon‐Lise T.
Published: July 2012

In this commentary, we argue that although randomization has many benefits, not all questions we seek to answer fit into a randomized setting. Our argument utilizes the clinical setting of carotid atherosclerosis management where specific clinical questions are answered by using a variety of comparative effectiveness designs. Observational studies should not be ruled out when designing studies to address questions of comparative effectiveness. Copyright © 2012 John Wiley & Sons, Ltd.
Methods for analyzing data from probabilistic linkage strategies based on partially identifying variables
Authors: Hof M. H. P. , Zwinderman A. H.
Published: July 2012

In record linkage studies, unique identifiers are often not available, and therefore, the linkage procedure depends on combinations of partially identifying variables with low discriminating power. As a consequence, wrongly linked covariate and outcome pairs will be created and bias further analysis of the linked data. In this article, we investigated two estimators that correct for linkage error in regression analysis. We extended the estimators developed by Lahiri and Larsen and also suggested a weighted least squares approach to deal with linkage error. We considered both linear and logistic regression problems and evaluated the performance of both methods with simulations. Our results show that all wrong covariate and outcome pairs need to be removed from the analysis in order to calculate unbiased regression coefficients in both approaches. This removal requires strong assumptions on the structure of the data. In addition, the bias significantly increases when the assumptions do not hold and wrongly linked records influence the coefficient estimation. Our simulations showed that both methods had similar performance in linear regression problems. With logistic regression problems, the weighted least squares method showed less bias. Because the specific structure of the data in record linkage problems often leads to different assumptions, it is necessary that the analyst has prior knowledge on the nature of the data. These assumptions are more easily introduced in the weighted least squares approach than in the Lahiri and Larsen estimator. Copyright © 2012 John Wiley & Sons, Ltd.
A Bayesian predictive sample size selection design for single‐arm exploratory clinical trials
Authors: Teramukai Satoshi , Daimon Takashi , Zohar Sarah
Published: July 2012

The aim of an exploratory clinical trial is to determine whether a new intervention is promising for further testing in confirmatory clinical trials. Most exploratory clinical trials are designed as single‐arm trials using a binary outcome with or without interim monitoring for early stopping. In this context, we propose a Bayesian adaptive design denoted as predictive sample size selection design (PSSD). The design allows for sample size selection following any planned interim analyses for early stopping of a trial, together with sample size determination before starting the trial. In the PSSD, we determine the sample size using the method proposed by Sambucini (Statistics in Medicine 2008; 27:1199–1224), which adopts a predictive probability criterion with two kinds of prior distributions, that is, an ‘analysis prior’ used to compute posterior probabilities and a ‘design prior’ used to obtain prior predictive distributions. In the sample size determination of the PSSD, we provide two sample sizes, that is, N and Nmax, using two types of design priors. At each interim analysis, we calculate the predictive probabilities of achieving a successful result at the end of the trial using the analysis prior in order to stop the trial in case of low or high efficacy (Lee et al., Clinical Trials 2008; 5:93–106), and we select an optimal sample size, that is, either N or Nmax as needed, on the basis of the predictive probabilities. We investigate the operating characteristics through simulation studies, and the PSSD retrospectively applies to a lung cancer clinical trial. (243) Copyright © 2012 John Wiley & Sons, Ltd.
Two Dimensional Nanoarrays of Individual Protein Molecules
Authors: Shen Lei , Garland Adam , Wang Yini , Li Zicheng , Bielawski Christopher W. , Guo Athena , Zhu X.‐Y.
Published: July 2012

Protein molecules on solid surfaces are essential to a number of applications, such as biosensors, biomaterials, and drug delivery. In most approaches for protein immobilization, inter‐molecular distances on the solid surface are not controlled and this may lead to aggregation and crowding. Here, a simple approach to immobilize individual protein molecules in a well‐ordered 2D array is shown, using nanopatterns obtained from a polystyrene‐block‐poly(2‐hydroxyethyl methacrylate) (PS‐b‐PHEMA) diblock copolymer thin film. This water‐stable and protein‐resistant polymer film contains hexagonally ordered PS cylindrical domains in a PHEMA matrix. The PS domains are activated by incorporating alkyne‐functionalized PS and immobilizing azide‐tagged proteins specifically onto each PS domain using “Click” chemistry. The nanometer size of the PS domain dictates that each domain can accommodate no more than one protein molecule, as verified by atomic force microscopy imaging. Immunoassay shows that the amount of specifically bound antibody scales with the number density of individual protein molecules on the 2D nanoarrays.
Analisys of Electric Arc Furnace Slag
Authors: Mombelli Davide , Mapelli Carlo , Gruttadauria Andrea , Baldizzone Claudio , Magni Francesco , Levrangi Pier Luca , Simone Piero
Published: July 2012

The black slag produced during the melting process in electric arc furnace can be used as adjunct in the operation of land filling, building operation of road grounds, and production of concrete. Their use limitation is due to the presence of polluting chemical elements, including Cr, Ba, V, Mo, etc, that can be dangerous for human and environment, resulting by using of polluted scraps (i.e., painted, lubricated, or polymeric compound scraps). The release extent of polluting elements appears to behave as a function of the constituent phases, i.e., CaO, SiO2, Al2O3, MgO, etc. The main tools employed in the characterization of the black slag consists in optical basicity calculation, SEM‐EBS and SEM‐EDS analysis. The combination of the data coming from chemical analysis, micro‐structural examination and releasing tests allows to identify the correct chemical range avoiding dangerous chemical release and to develop a working disposal procedure for the investigated slag.
Micro‐Segregation Behavior of Solute Elements in the Mushy Zone of Continuous Casting Wide‐Thick Slab
Authors: Wang Weiling , Zhu Miaoyong , Cai Zhaozhen , Luo Sen , Ji Cheng
Published: July 2012

Based on the assumption that the transverse cross‐section of dendrites is a regular hexagon, a coupled macro‐heat transfer and solute diffusion model was developed to describe micro‐segregation behavior of solute elements in the mushy zone during wide‐thick slab continuous casting. The heat transfer model and the micro‐segregation model were validated by the industrial tests and the experiment measurements in literatures, respectively. The results show that the cooling rate decreases from 51.1°C s−1 at the surface to 0.13°C s−1 at the center of the wide‐thick slab of peritectic steel continuous casting. The effective cooling rate equaling to 1.78°C s−1 mainly depends on mold cooling and varies little with casting speed. The micro‐segregation behavior of solute elements in the mushy zone depends on back diffusion ability and local equilibrium at interfaces. Compared with other elements in the steel, phosphorus, and sulfur elements exhibit a much higher segregation ratio at the end of the solidification and are more significantly affected by the initial carbon content.
An Experimental Study of a Flux Modulated Solid State Metathesis Reaction
Authors: Poser Jessica D. , Meyer H.‐Jürgen
Published: July 2012

A solid state metathesis (SSM) reaction was investigated with respect to the formation of rare‐earth carbodiimides, the role of the co‐produced salt (LiCl), and the eutectic flux medium (LiCl/KCl). A SSM reaction is characterized by an exothermic reaction in which a salt (often LiCl) is coproduced. When the salt melts, it can serve as a useful medium for the crystallization of a desired product. An improved crystal growth can be observed by using an eutectic flux. However, the composition of an eutectic LiCl/KCl flux is altered when LiCl is produced during the reaction. The thermal effects concerning the endothermic melting of the flux and the exothermic ingnition of the SSM reaction may compensate each other, which is not necessarily a drawback for the reaction to proceed.
Voriconazole for chronic pulmonary aspergillosis: a prospective multicenter trial
Authors: Cadranel J. , Philippe B. , Hennequin C. , Bergeron A. , Bergot E. , Bourdin A. , Cottin V. , Jeanfaivre T. , Godet C. , Pineau M. , Germaud P.
Published: July 2012

Early evidence suggests the efficacy of voriconazole for chronic pulmonary aspergillosis (CPA). We conducted a prospective, open, multicenter trial to evaluate the efficacy and safety of voriconazole for proven CPA in minimally or non-immunocompromised patients. Patients had CPA confirmed by chest computed tomography (CT) and/or endoscopy, positive Aspergillus culture from a respiratory sample, and positive serologic test for Aspergillus precipitins. Patients received voriconazole (200 mg twice daily) for a period of 6–12 months and were followed for 6 months after the end of therapy (EOT). The primary endpoint was global success at 6 months, defined as complete or partial (≥50 % improvement) radiological response and mycological eradication. Forty-one patients with confirmed CPA were enrolled. All patients had A. fumigatus as the etiologic agent. By EOT, five patients had died from comorbidities and seven had discontinued voriconazole due to toxicity. The global success rate at 6 months was 13/41 (32 %): 10/19 (53 %) for chronic necrotizing aspergillosis and 3/22 (14 %) for chronic cavitary aspergillosis (p = 0.01). The respective success rates at EOT were 58 and 32 %. Clinical symptoms and quality of life also improved during treatment. Voriconazole is effective for CPA, with acceptable toxicity. The response rate is higher and obtained more rapidly in necrotizing than cavitary forms.
Dyadic Variability in Mother-Adolescent Interactions: Developmental Trajectories and Associations with Psychosocial Functioning
Authors: Van der Giessen Daniёlle , Branje Susan J. T. , Frijns Tom , Meeus Wim H. J.
Published: July 2012

Dyadic variability is considered to be a key mechanism in the development of mother-adolescent relationships, and low levels of dyadic flexibility are thought to be associated with behavior and relationship problems. The present observational study examined heterogeneity in the development of dyadic variability in mother-adolescent interactions and associations with psychosocial functioning. Dyadic variability refers to the range of emotional states during interactions of mother-adolescent dyads. During five annual home visits, 92 mother-adolescent dyads (M age T1 = 13; 65.2 % boys) were videotaped while discussing a conflict, and they completed several questionnaires on adolescents’ aggressive behavior and adolescents’ and mothers’ perceived relationship quality. Two types of dyads were distinguished: low variability dyads (52 %) and high decreasing variability dyads (48 %). Over time, high decreasing variability dyads were characterized by a broader emotional repertoire than low variability dyads. Moreover, these two dyad types had distinct developmental patterns of psychosocial adjustment. Over time, high decreasing variability dyads showed lower levels of adolescents’ aggressive behavior, and higher levels of perceived relationship quality than low variability dyads. These findings suggest that over time more dyadic variability is associated with less adjustment problems and a more constructive development of the mother-adolescent relationship. Adaptive interactions seem to be characterized by a wider range of emotional states and mothers should guide adolescents during interactions to express both positive and negative affect. Observing the dyadic variability during mother-adolescent interactions can help clinicians to distinguish adaptive from maladaptive mother-adolescent dyads.
Geschlechtersensible Forschung in der Epidemiologie – eine Einladung
Authors: Gansefort Dirk , Jahn Ingeborg
Published: July 2012

Einleitung

Immer häufiger werden Epidemiologen und Epidemiologinnen mit der Anforderung konfrontiert, ihre Forschung geschlechtersensibel auszugestalten. Obwohl in der epidemiologischen Forschung überwiegend nach Männern und Frauen differenziert analysiert wird, fehlt bisher eine umfassende Integration der Kategorie Geschlecht. Mit diesem Artikel wollen wir Ansätze einer geschlechtersensiblen Forschung sowie ein Projekt und Ideen für den weiteren Weg zu einer geschlechtersensiblen Forschung vorstellen.
A candidate gene study of one-carbon metabolism pathway genes and colorectal cancer risk
Authors: Martinelli Marcella , Scapoli Luca , Mattei Gabriella , Ugolini Giampaolo , Montroni Isacco , Zattoni Davide , Rosati Giancarlo , Solmi Rossella
Published: July 2012

The risk of colorectal cancer (CRC) may be influenced by aberrant DNA methylation and altered nucleotide synthesis and repair, possibly caused by impaired dietary folate intake as well as by polymorphic variants in one-carbon metabolism genes. A case–control study using seventy-one CRC patients and eighty unrelated healthy controls was carried out to assess the genetic association of fifteen SNP and one insertion in nine genes belonging to the folate pathway. Polymorphism selection was based on literature data, and included those which have a known or suspected functional impact on cancer and missense polymorphisms that are most likely to alter protein function. Genotyping was performed by real-time PCR and PCR followed by restriction analysis. The likelihood ratio statistic indicated that most of the polymorphisms were not associated with the risk of CRC. However, an increased risk of CRC was observed for two variant alleles of SNP mapping on the transcobalamin 2 gene (TCN2): C776G (rs1801198) and c.1026-394T>G (rs7286680). Considering the crucial biological function played by one-carbon metabolism genes, further investigations with larger cohorts of CRC patients are needed in order to confirm our preliminary results. These preliminary results indicate that TCN2 polymorphisms can be a susceptibility factor for CRC.