bluuebunny/crossref_metadata_2025 huggingface dataset:
The genomic landscape of meiotic crossovers and gene conversions in Arabidopsis thaliana
Authors: Wijnker Erik , Velikkakam James Geo , Ding Jia , Becker Frank , Klasen Jonas R , Rawat Vimal , Rowan Beth A , de Jong Daniël F , de Snoo C Bastiaan , Zapata Luis , Huettel Bruno , de Jong Hans , Ossowski Stephan , Weigel Detlef , Koornneef Maarten , Keurentjes Joost JB , Schneeberger Korbinian
Published: December 2013

Knowledge of the exact distribution of meiotic crossovers (COs) and gene conversions (GCs) is essential for understanding many aspects of population genetics and evolution, from haplotype structure and long-distance genetic linkage to the generation of new allelic variants of genes. To this end, we resequenced the four products of 13 meiotic tetrads along with 10 doubled haploids derived from Arabidopsis thaliana hybrids. GC detection through short reads has previously been confounded by genomic rearrangements. Rigid filtering for misaligned reads allowed GC identification at high accuracy and revealed an ∼80-kb transposition, which undergoes copy-number changes mediated by meiotic recombination. Non-crossover associated GCs were extremely rare most likely due to their short average length of ∼25–50 bp, which is significantly shorter than the length of CO-associated GCs. Overall, recombination preferentially targeted non-methylated nucleosome-free regions at gene promoters, which showed significant enrichment of two sequence motifs.
Ready, set, differentiate!
Authors: Sancho Margarida , Rodríguez Tristan A
Published: December 2013

The expression of E-Cadherin, a protein best known for its role in cell adhesion, regulates the onset of embryonic differentiation.
Agentive reflexive clitics and transitive 'se' constructions in Spanish
Authors: Armstrong Grant
Published: December 2013

<span style="font-size: 10.0pt; font-family: "Times New Roman","serif"; mso-fareast-font-family: "ＭＳ 明朝"; mso-fareast-theme-font: minor-fareast; mso-bidi-theme-font: minor-bidi; mso-ansi-language: EN-GB; mso-fareast-language: EN-US; mso-bidi-language: AR-SA;" lang="EN-GB">This paper investigates the structure of transitive sentences that contain a non-doubling reflexive clitic such as Juan se lavó todos los platos and María se leyó un libro. Though these are traditionally labelled unselected (non-core) agreeing datives or aspectual datives, I argue that this label obscures a relevant difference between two classes of constructions. agentive reflexive clitic (= ARC) constructions are characterized by a uniform set of effects on the external argument (= it must be an agent) and the aspectual interpretation of the VP (= it must be an accomplishment). On the other hand, transitive se clitic (= TSC) constructions do not impose any type of uniform restrictions on the kind of external argument they take or on the aspectual interpretation of the VP. I propose that the difference between these two constructions may be captured by treating se in the ARC construction as the realization of a special vDO head, based on an idea in Folli & Harley (2005), while se in the TSC construction is generated in the complement position of the verb and incorporates into V, forming a complex predicate, following work by De Cuyper (2006), MacDonald (2004, 2008) and MacDonald & Huidobro (2010). It is shown that many of the empirical and theoretical disagreements that plague the literature on the role of non-doubling se in transitive sentences have a simple solution given the new division established here
(Esa tela) se la descose: la pronominalización del paciente en las impersonales reflejas del español peninsular
Authors: De Benito Moreno Carlota
Published: December 2013

En este trabajo investigamos la pronominalización del paciente en las oraciones conocidas como impersonales reflejas en español peninsular, desde dos puntos de vista: el tipo de paciente que se pronominaliza y el pronombre que se emplea para ello. En general, se entiende que en español estándar solo pronominalizan los pacientes humanos y definidos en este contexto, pero algunas variedades presentan menos restricciones en cuanto a las características del paciente. Asimismo, se ha discutido largamente la cuestión del pronombre empleado en estas pronominalizaciones, pues se documentan tanto las formas de dativo (le(s)) como las de acusativo (la(s), lo(s)). Empleando datos dialectales del español oral peninsular, investigamos la distribución geográfica y contextual de ambas cuestiones y proponemos que solo puede entenderse el tipo de pronombre utilizado en relación con la pronominalización de pacientes no humanos y con los sistemas pronominales propios de cada variedad.
Calculation of electron spin relaxation time in germanium using the projection–reduction method
Authors: Kang Nam Lyong , Choi Sang Don
Published: December 2013

Using the electron spin resonance formula derived by the projection reduction method, the electron spin relaxation times in a system of electrons interacting with phonons through phonon-modulated spin–orbit coupling are calculated. The electron spin relaxation time (T
1) in germanium decreases with increasing temperature (T) as

at low temperatures and

at high temperatures. This means that electrons are scattered mostly by acoustic phonon deformation at low temperatures and optical phonon deformation at high temperatures. The magnetic field (B) dependence of the relaxation time is

at 70 K and

at 120 K. These results nearly agree with the prediction of Yafet. It is also shown that the acoustic and optical deformation constants do not affect the temperature dependence of the relaxation time.
Less reliable water availability in the 21st century climate projections
Authors: Kumar Sanjiv , Lawrence David M. , Dirmeyer Paul A. , Sheffield Justin
Published: December 2013

The temporal variability of river and soil water affects society at time scales ranging from hourly to decadal. The available water (AW), i.e., precipitation minus evapotranspiration, represents the total water available for runoff, soil water storage change, and ground water recharge. The reliability of AW is defined as the annual range of AW between local wet and dry seasons. A smaller annual range represents greater reliability and a larger range denotes less reliability. Here we assess the reliability of AW in the 21st century climate projections by 20 climate models from phase 5 of the Coupled Model Intercomparison Project (CMIP5). The multimodel consensus suggests less reliable AW in the 21st century than in the 20th century with generally decreasing AW in local dry seasons and increasing AW in local wet seasons. In addition to the canonical perspective from climate models that wet regions will get wetter, this study suggests greater dryness during dry seasons even in regions where the mean climate becomes wetter. Lower emission scenarios show significant advantages in terms of minimizing impacts on AW but do not eliminate these impacts altogether.

Modeling of future water availability predicts that wet regions become wetter and dry regions become drier, leading to an increasing likelihood of seasonal droughts and floods in regions where such vulnerability is already high.
Spacecraft Improves Understanding of Turbulent “Interface” Region of the Sun
Authors: Showstack Randy
Published: December 2013

The region of the Sun between its surface and its outer atmosphere is even more violent and turbulent than had been expected and better knowledge about that little‐understood region could improve our understanding of space weather, scientists involved with NASA's Interface Region Imaging Spectrograph (IRIS) said at a 9 December briefing at the AGU Fall Meeting in San Francisco, Calif.
Concern About Abrupt Climate Changes Prompts Call for Early Warning System
Authors: Showstack Randy
Published: December 2013

Abrupt changes in Earth's physical climate system—as well as abrupt impacts to physical, biological, or human systems from even gradual changes in the climate system—could lead to major disruptions, according to a report from the U.S. National Research Council (NRC) released on 3 December 2013. Moreover, there is an urgent need for an early warning system to better understand, anticipate, and prepare for those changes, the report states.
Using new satellite data would improve hurricane forecasts
Authors: Schultz Colin
Published: December 2013

To track and forecast the development of dangerous tropical cyclones, the National Weather Service's National Centers for Environmental Prediction uses a model known as the Hurricane Weather Research and Forecasting (HWRF) system. HWRF is an operational model that calculates a hurricane's likely path and intensity, but the system currently does not use data pulled from weather satellites because of mixed results when data were assimilated from early weather satellites.
Comparison of Subantarctic Mode Water and Antarctic Intermediate Water formation rates in the South Pacific between NCAR‐CCSM4 and observations
Authors: Hartin Corinne A. , Fine Rana A. , Kamenkovich Igor , Sloyan Bernadette M.
Published: December 2013

Average formation rates for Subantarctic Mode Water (SAMW) and Antarctic Intermediate Water (AAIW) in the South Pacific are calculated from the National Center for Atmospheric Research Community Climate System Model version 4 (NCAR‐CCSM4), using chlorofluorocarbon inventories (CFC‐12). When compared to observations, CCSM4 accurately simulates the southeast Pacific as the main formation region for SAMW and AAIW. Formation rates for SAMW in CCSM4 are 3.4 sverdrup (Sv), about half of the observational rate, due in part to shallow mixed layers, a thinner SAMW layer, and insufficient meridional transport. A formation rate of 8.1 Sv for AAIW in CCSM4 is higher than observations due to higher inventories in the southwest and central Pacific and surface concentrations within CCSM4. Also, a lack of data in the southwest Pacific may bias the observational rate low. This model‐observation comparison is useful for understanding the uptake and transport of other gases, e.g., CO2 by the model.
Preparation and Characterization of Antibacterial Dental Resin with UDMQA‐12
Authors: Huang Qiting , Lin Zhengmei , Liang Xiaoxu , Liu Fang , He Jingwei
Published: December 2013

In this study, urethane methacrylate quaternary ammonium compound (UDMQA‐12) was used to partially replace 2,2‐bis[4‐(2‐hydroxy‐3‐methacryloyloxypropyl)‐phenyl]propane (Bis‐GMA) as the base compound of dental resin system. Double bond conversion, polymerization shrinkage, flexural strength (FS) and flexural modulus (FM), water sorption (WS) and water solubility (WSL), and antibacterial activity of all experimental resins were investigated. Bis‐GMA/triethyleneglycol dimethacrylate resin without UDMQA‐12 was used as a control group. Results showed that UDMQA‐12 had no negative influence on the double bond conversion of the resin, but polymerization shrinkage, FS, and FM decreased with the increasing of UDMQA‐12 concentration, whereas WS and WSL increased with it. UDMQA‐12–containing polymer showed antibacterial activity when concentration of UDMQA‐12 was 30% or more. © 2013 Wiley Periodicals, Inc. Adv Polym Technol 2014, 33, 21395; View this article online atwileyonlinelibrary.com. DOI 10.1002/adv.21395
Investigation of the Influence of Nanoclay on the Mechanical, Thermal, and Morphological Behaviors of Polyurethane/Ginger Spent Hybrid Composites
Authors: Chethana M. , Ramaraj B. , Siddaramaiah B. S. Madhukar
Published: December 2013

With an objective to investigate the influence of nanoclay (NC) on the mechanical, thermal, and morphological properties of polyurethane (PU) in the presence of 5 wt% of ginger spent (GS), PU/GS/NC nanocomposite films were fabricated by a solution intercalation method with varying amounts, namely 0, 0.5, 1.0, and 2.0 wt%, of NC. The fabricated PU/GS/NC nanocomposite films were characterized by Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD) analysis, and scanning electron microscopy (SEM). The mechanical properties such as the tensile strength, tensile modulus, percentage elongation at break, and surface hardness have been performed for nanocomposites. FT‐IR and XRD analysis show the nature of the NC interaction with the PU matrix, whereas SEM images show agglomeration of NC and entanglement of polymer chains with NC with an increase in the NC content. It was found that the tensile strength of the biocomposites increased from 4.5 to 13.7 MPa, tensile modulus increased from 8.2 to 14.3 MPa, and surface hardness increased from 70 to 77 shore A, whereas the percentage elongation at break decreased from 155.2% to 100.5%. Static water contact angle measurements on the surface of the PU/GS/NC nanocomposites reveal a reduction in surface polarity by way of changes in the contact angle from 76.83° to 55.24°, whereas surface energy increased from 88.36 to 102.11 mJ/m2 with an increase in the NC content. With an increase in the NC content, the chemical resistance of the green composites in different chemical environments improved. Thermal analysis by a thermogravimetric analyzer indicates improvement in thermal stability with an increase in the NC content. © 2013 Wiley Periodicals, Inc. Adv Polym Technol 2014, 33, 21404; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21404
Eucalyptus Essential Oil‐Doped Alginate Fibers as a Potent Antibacterial Wound Dressing
Authors: Khajavi Ramin , Abbasipour Mina , Barzi Mehdi Ghafari , Rashidi Abosaeed , Rahimi Mohammad Karim , Mirzababa Hamed Haji
Published: December 2013

Eucalyptus essential oil (EEO) mainly consists of a natural organic compound named eucalyptol (1,8 cineole). It is a potential anti‐inflammatory, antiseptic, and antibacterial substance owing to its germicidal properties. Wound Dressing based on alginate fibers are also well known for caring of moderate‐ to highly exuding chronic and acute wounds. So, it was intended to load alginate with cineole to obtain a natural antibacterial fiber. EEO was loaded to a spinning dope of alginate. EEO‐doped alginate fibers were fabricated by wet spinning method, and then as‐spun fibers were consolidated in coagulation baths containing divalent cations. The cineol content of EEO, as its most active antibacterial agent, was measured by gas chromatography–mass spectrometry. Fibers were analyzed by scanning electron microscope, Fourier transform infrared spectroscopy (FTIR), and X‐ray diffraction (XRD), and their tensile mechanical properties were determined by a Shirley's strength tester. Antibacterial efficiency of samples was studied by measuring their zone of inhibition against a gram‐positive organism (Staphylococcus aureus) in accordance with American Association of Textile Chemists and Colorists (AATTC) test method 147. The cross section of EEO‐loaded alginate fibers was rounder and their tensile mechanical properties didn't decline significantly in comparison with unloaded alginate fibers. The presence of antibacterial activity observed for loaded samples and improved by increasing the EEO content of fibers. To consider the produced antibacterial activity and intrinsic properties of alginate, EEO‐loaded alginate fibers are proposed for occlusive or semiocclusive Wound Dressing. © 2013 Wiley Periodicals, Inc. Adv Polym Technol 2014, 33, 21408; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21408
Residency and career satisfaction among Anglo‐American model emergency medicine residents in Japan
Authors: Hagiwara Yusuke , Hasegawa Kohei , Chiba Takuyo , Watase Hiroko
Published: December 2013

Aim

The number of institutions providing Anglo‐American model emergency medicine has increased with the rise in its social demand in Japan. The ER Committee of the Japanese Association for Acute Medicine has introduced a residency model for use in Japanese hospitals that have adopted the Anglo‐American emergency medicine model. Despite the critical importance of its quality, no studies have examined Japanese emergency medicine residents' level of satisfaction with their training. This study investigated their residency and career satisfaction, and factors associated with satisfaction.

Methods

We developed a cross‐sectional, anonymous survey. Data were obtained from 67 Anglo‐American model emergency medicine residents in Japan in February 2010. Data were analyzed with factor analysis and multivariable analysis with a logistic regression model.

Results

Response rate was 100% (n = 67). Overall, 50.7% and 67.2% of residents reported high residency and career satisfaction, respectively. Factor analysis derived four factors: working conditions; stress reduction; training systems; education. Logistic regression analysis revealed that the training system factor was significantly associated with high residency satisfaction (odds ratio [OR], 2.9; 95% confidence interval [CI], 1.2–8.4) and the stress reduction factor was significantly associated with high career satisfaction (OR, 3.0; 95%CI, 1.2–8.4). A total of 28.8% reported intentions to switch specialties. The intention was not significantly associated with low residency satisfaction (OR, 1.7; 95%CI, 0.6–5.0), but was associated with low career satisfaction (OR, 5.1; 95%CI, 1.6–16.0).

Conclusion

Improvements in training systems and stress reduction may increase residency and career satisfaction of emergency medicine residents, respectively. This study suggested that high career satisfaction was required to secure future emergency physicians.
Regulated small rivers as ‘nursery’ areas for invasive largemouth bassMicropterus salmoidesin Iberian waters
Authors: Almeida David , Grossman Gary D.
Published: December 2013

Few studies have assessed the ecological role of regulated small rivers in the environmental biology of invasive largemouth bassMicropterus salmoidesin Iberian waters.

Size structure, diet, physical condition, and developmental stress of largemouth bass populations were compared between two contrasting habitats in the Iberian Peninsula, the Encinarejo Reservoir and the small River Jándula below the dam (Guadalquivir River Basin, southern Spain).

Size structure differed between river and reservoir populations of small (<180 mm FL) largemouth bass, with a higher proportion of individuals between 30 and 60 mm in the river and a higher proportion of 20–40 mm individuals in the reservoir. In the river, the most important prey for small largemouth bass were Ephemeroptera, Plecoptera and Odonata nymphs. In the reservoir, Gerridae insects and pumpkinseedLepomis gibbosuswere the most important prey in terms of ingested biomass for small largemouth bass, whereas large individuals consumed high percentages of common carpCyprinus carpioand pumpkinseed. Prey richness, trophic niche breadth, and trophic diversity were significantly higher in small largemouth bass from the river, as well as eviscerated mass and glucose level. Fluctuating asymmetry was lower in the river for branched rays of pectoral fins, eye diameter, and length of pectoral fins.

Overall results indicate that largemouth bass are taking advantage of both habitat differentiation and flow regulation in Mediterranean streams. Therefore, regulated small rivers may play an ecological role as ‘nursery’ areas, where developmental stress is low and thus, juvenile fish can display better body condition and nutritional status than their reservoir counterparts.

The present study provides information relevant to the management of largemouth bass and subsequent conservation of the valuable and endemic Iberian fish fauna. For example, size‐specific culls in the reservoirs and below the dams are suggested strategies to control the reinforcement of downstream populations.

Copyright © 2013 John Wiley & Sons, Ltd.
On the Size Evolution of Monolayer‐Protected Gold Clusters during Ligand Place‐Exchange Reactions: The Effect of Solvents
Authors: Kuo Chun‐Ting , Chen Chiu‐Feng , Gu Meng‐Wen , Su Man‐Nung , Huang Jhih‐Fong , Huang Min‐Jie , Chen Chun‐hsien
Published: December 2013

Ligand place‐exchange (LPE) reactions are extensively applied for the post‐functionalization of monolayer‐protected gold clusters (MPCs) by using excessive incoming ligands to displace initial ones. However, the modified MPCs are often enlarged or degraded; this results in ill‐defined size‐dependent properties. The growth of MPCs essentially involves an unprotected surface that is subsequently has gold atoms added or is fused with other gold cores owing to collision. Reported herein is a guideline for the selection of solvents to suppress unwanted MPC growth. Favorable solvents are those with significant affinity to gold or with low solubility for desorbed ligands because these properties retard LPE reactions and minimize the time available for unprotected gold cores. This finding provides a general and convenient approach to regulate the size of functionalized MPCs.
Development and validation of an LC‐MS/MS method for simultaneous quantitative analysis of free and conjugated bisphenol A in human urine
Authors: Battal Dilek , Cok Ismet , Unlusayin Irfan , Tunctan Bahar
Published: December 2013

Bisphenol A (BPA) is an environmental endocrine‐disrupting chemicals that is widely used in common consumer products. There is an increasing concern regarding human exposure to BPA owing to the potential adverse effects associated with its estrogenic activity. For assessing environmental exposure to BPA, it is essential to have a sensitive, accurate and selective analytical method, especially one that can detect low BPA levels in complex sample matrices. In this study, we developed and validated an accurate, sensitive, and robust liquid chromatography–tandem mass spectrometry method for simultaneous quantification of free BPA and BPA β‐d‐glucuronide (BPA‐gluc) concentrations in human urine with only a single injection. Calibration curves were linear over a concentration range of 1–100 ng/mL for BPA and 10–1000 ng/mL for BPA‐gluc. The levels of the analytes were determined quantitatively with HPLC/ESI‐MS/MS by using negative electrospray ionization in the select ion monitoring mode and a pentaflouraphenyl propyl column. The validated method was applied to the analysis of spot urine specimens collected from randomly selected healthy human subjects. Copyright © 2013 John Wiley & Sons, Ltd.
Cutaneous innervation of the ankle: An anatomical study showing danger zones for ankle surgery
Authors: Duscher Dominik , Wenny Raphael , Entenfellner Johanna , Weninger Patrick , Hirtler Lena
Published: December 2013

Three nerves innervate the skin in the foot and ankle region: the saphenous, sural, and superficial peroneal nerves. Because they are close to the medial and lateral malleoli, these nerves are at significant risk during orthopedic interventions. The aims of this study were to investigate the distal courses of the three cutaneous nerves of the ankle and to determine their exact relationships with easily identifiable bony landmarks. Ten freshly frozen and 40 embalmed lower extremities of adults were dissected. The positions of the superficial peroneal, sural, and saphenous nerves were determined using reference lines based on easily palpable osseous landmarks. The frequencies and distributions of all three nerves and their branches were converted into absolute numbers. A danger zone for each nerve was established on the basis of the distribution of crossings between the nerves and the different reference lines. Determination of the exact orientation of the nerves around the ankle should help minimize the nerve injury rate during surgical approaches in this area. Using this easily translatable new grid system, the course and danger zones of each cutaneous nerve around the ankle can be estimated clinically. Clin. Anat. 653–658, 2014. © 2013 Wiley Periodicals, Inc.
Superoleophobic Meshes with Relatively Low Hysteresis and Sliding Angles by Electropolymerization: Importance of Polymer‐Growth Control
Authors: Darmanin Thierry , Tarrade Jeanne , Celia Elena , Bellanger Herve , Guittard Frederic
Published: December 2013

Invited for this month’s cover is the group of Prof. Frederic Guittard from Université Nice Sophia–Antipolis. The cover picture shows a superoleophobic stainless‐steel mesh obtained by electrodeposition of fluorinated conducting polymers. Read the full text of the article at 10.1002/cplu.201300315
Comparative study of DHA‐enriched phospholipids and EPA‐enriched phospholipids on metabolic disorders in diet‐induced‐obese C57BL/6J mice
Authors: Liu Xiaofang , Cui Jie , Li Zhaojie , Xu Jie , Wang Jingfeng , Xue Changhu , Wang Yuming
Published: December 2013

Recent reports have shown that n‐3 PUFA‐enriched phospholipids have various beneficial effects. The proportion of DHA and eicosapentaenoic acid (EPA) in the phospholipids might affect their biological functions. In the present study, marine DHA‐enriched phospholipids (DHA‐PL) and EPA‐enriched phospholipids (EPA‐PL) were administered to high fat (HF) diet‐induced obese C57BL/6J mice for 8 weeks to compare their effects on obesity‐related metabolic disorders. DHA‐PL and EPA‐PL significantly decreased epididymal and perirenal adipose tissue weights, reduced blood pressures and lowered serum and hepatic triacylglycerol levels in HF diet‐induced obese mice. Serum insulin, MCP‐1 and IL‐6 levels were also efficiently reduced by treatment with DHA‐PL and EPA‐PL. The anti‐obesity and lipid‐lowering effects of EPA‐PL were superior to DHA‐PL, while DHA‐PL exhibited better anti‐hypertension effects than EPA‐PL. The effects of DHA‐PL and EPA‐PL on glucose intolerance and inflammation were basically equivalent. DHA‐PL and EPA‐PL up‐regulated genes involved in insulin‐sensitizing actions in the adipose tissue and suppressed hepatic SREBP‐1c mediated lipogenesis. EPA‐PL also significantly activated PPARα mediated fatty acid β‐oxidation in the liver. These results indicate that DHA‐PL and EPA‐PL could efficaciously alleviate obesity‐related metabolic disorders but the ameliorative degree and regulatory mechanisms are not identical.

Practical applications: This investigation would be useful in the selective development of functional foods containing DHA‐PL or EPA‐PL contributing to the prevention and treatment of chronic metabolic disease in humans. The study also showed the chemical compositions of phospholipids fractions of squid (Sthenoteuthis oualaniensis) egg and sea cucumber (Cucumaria frondosa) that may be useful for further studies.
Synthesis of Epibatidine Analogues Having a 2‐Substituted 2‐Azabicyclo[2.2.2]octane Skeleton
Authors: Wauters Iris , De Blieck Ann , Muylaert Koen , Heugebaert Thomas S. A. , Stevens Christian V.
Published: December 2013

The synthesis of 1‐cyano‐2‐aza‐[2.2.2]bicyclooctanes has been studied using the dynamic cyanide addition to cyclohexanone derivatives. These compounds were further elaborated into a new class of epibatidine derivatives from which a number of examples were fully deprotected to give the potentially active compounds. The highly hydrophilic character of the compounds resulted in a difficult isolation and purification of the epibatidine analogues.
Processes involved in sweeping as sample enrichment method in cyclodextrin‐modified micellar electrokinetic chromatography of hydrophobic basic analytes
Authors: El‐Awady Mohamed , Pyell Ute
Published: December 2013

Sweeping is an enrichment method in MEKC, which includes following steps: stacking/destacking of the micelles, sweeping of analyte by the stacked/destacked micelles, destacking/stacking of the swept analyte zone and additional focusing/defocusing due to the retention factor gradient effect (RFGE). In this study, we investigate additional processes, regarding online focusing in cyclodextrin‐modified MEKC (CD‐MEKC) of hydrophobic basic analytes: dynamic pH junction (sample with pH different from that of BGE) and adsorption of analyte onto the capillary wall within the sample zone. It is demonstrated that the developed method for the assessment of the sweeping efficiency is also applicable to CD‐MEKC taking ethylparaben as an example of acidic analytes and desloratadine as an example of basic analytes using different types of β‐cyclodextrin. Our previous results regarding RFGE as an additional focusing/defocusing effect in sweeping‐MEKC are confirmed for the case that the apparent distribution coefficient differs for the sample and the BGE due to a different content of the complex‐forming agent cyclodextrin and due to a pH difference between the sample and the BGE. Despite being significantly more hydrophobic than ethylparaben, desloratadine shows an unexpectedly low enrichment factor. This enrichment factor is nearly unaffected by the addition of CD to the BGE. This unexpected behavior is attributed to wall adsorption of the protonated hydrophobic basic analyte within the sample zone, which significantly counteracts the sweeping process. This assumption is corroborated by an improvement in the enrichment factor achieved via addition of a dynamic coating agent (triethylamine) to the sample solution.
Amphiphilic polymeric micelle as pseudostationary phase in electrokinetic chromatography for analysis of eight corticosteroids in cosmetics
Authors: Xu Xiaojin , Ni Xinjiong , Cao Yuhua , Zhuo Xiaolu , Yang Xiaoxiao , Cao Guangqun
Published: December 2013

Amphiphilic polymeric micelle, as a novel pseudostationary phase in EKC was used to determine eight kinds of corticosteroids namely hydrocortisone, prednisolone, hydrocortisone acetate, prednisone, cortisone acetate, prednisolone acetate, dexamethasone, and triamcinolone acetonide in cosmetics. Amphiphilic random copolymer poly(methyl methacrylate‐co‐methacrylic acid) (P(MMA‐co‐MAA)) was micellizated via neutralization in alkaline aqueous solution. The influences of the molar ratio of monomer MMA to MAA, the concentration of polymer and pH on the polymeric micelle microstructure and EKC performances were investigated. As molar ratio of MMA to MAA in P(MMA‐co‐MAA) increased, both CMC and environmental polarity of the inner core in polymeric micelle decreased dramatically. With increasing monomer ratio, the size of polymeric micelles increased firstly, and then decreased, finally increased again. ζ potential of the micelle had a slight decline trend. As increment of polymer concentration, the size of the polymeric micelle increased steadily. By optimizing the monomer ratio, the polymer concentration, and pH of the running buffer, as well as operation conditions such as separation voltage and temperature, the eight analytes could be separated within 16.5 min using 7.5 mg/mL polymer with the monomer ratio of 7:3 dissolved in pH 9.2 borax buffer as the running buffer. The method has been used for analysis of corticosteroids in cosmetic samples with simple extraction; the recoveries for eight analytes were between 85.9 and 106%. This method was of accuracy, repeatability, pretreatment simplicity, and could be applied to the quality control of cosmetics.
Dielectrophoretic separation of bioparticles in microdevices: A review
Authors: Jubery Talukder Z. , Srivastava Soumya K. , Dutta Prashanta
Published: December 2013

In recent years, dielectrophoretic force has been used to manipulate colloids, inert particles, and biological microparticles, such as red blood cells, white blood cells, platelets, cancer cells, bacteria, yeast, microorganisms, proteins, DNA, etc. This specific electrokinetic technique has been used for trapping, sorting, focusing, filtration, patterning, assembly, and separating biological entities/particles suspended in a buffer medium. Dielectrophoretic forces acting on particles depend on various parameters, for example, charge of the particle, geometry of the device, dielectric constant of the medium and particle, and physiology of the particle. Therefore, to design an effective micro‐/nanofluidic separation platform, it is necessary to understand the role of the aforementioned parameters on particle motion. In this paper, we review studies particularly related to dielectrophoretic separation in microfluidic devices. Both experimental and theoretical works by several researchers are highlighted in this article covering AC and DC DEP. In addition, AC/DC DEP, which uses a combination of low frequency AC and DC voltage to manipulate bioparticles, has been discussed briefly. Contactless DEP, a variation of DC DEP in which electrodes do not come in contact with particles, has also been reviewed. Moreover, dielectrophoretic force‐based field flow fractionations are featured to demonstrate the bioparticle separation in microfluidic device. In numerical front, a comprehensive review is provided starting from the most simplified effective moment Stokes‐drag (EMSD) method to the most advanced interface resolved method. Unlike EMSD method, recently developed advanced numerical methods consider the size and shape of the particle in the electric and flow field calculations, and these methods provide much more accurate results than the EMSD method for microparticles.
Continuous separation of multiple particles by negative and positive dielectrophoresis in a modified H‐filter
Authors: Lewpiriyawong Nuttawut , Yang Chun
Published: December 2013

The article presents a new application of the modified H‐filter with insulating rectangular blocks using negative and positive DEP for separation of multiple particles in a continuous pressure‐driven flow. The multiple insulating blocks fabricated along the main channel induce spatially nonuniform electric fields which exert differential repulsive (negative) or attractive (positive) DEP forces on particles, depending on the size and the polarizability of particles relative to their suspending medium. As a result, particles of different sizes and polarizability can be separated into different outlets of the H‐filter. Numerical simulations are also performed to analyze the effects of block gap and width on electric field distribution and DEP force characteristics near the insulating blocks so as to provide design guidelines for optimal structural dimensions of the microfluidic device. The device performance is demonstrated by separating a three‐sized particles mixture, including 2 μm fluorescent particles with an attractive DEP force and both 5 and 10 μm nonfluorescent particles with differential repulsive DEP forces. High separation rate of 99% is successfully achieved.
Micro solid‐phase derivatization analysis of low‐molecular mass aldehydes in treated water by micellar electrokinetic chromatography
Authors: Fernández‐Molina José María , Silva Manuel
Published: December 2013

A MEKC method was developed for the determination of aliphatic and aromatic low‐molecular mass aldehydes (LMMAs) in treated water samples. The method involves the precapillary derivatization and extraction of the aldehydes on a Telos™ENV μ‐SPE column impregnated with 2,4‐dinitrophenylhydrazine . After elution of the hydrazones with ACN, the derivatives were analyzed using MEKC–DAD. Resolution of the MEKC procedure was studied by changing the pH and the concentration of the buffer, the type, and the concentration of surfactant, and the organic modifier content in the BGE. A running buffer consisting of a phosphate buffer (pH 7.2, 75 mM) with CTAB (50 mM) and ACN (30%) gave the best results. Linearity was established over the concentration range 0.5–500 μg/L and LODs from 65 to 775 ng/L; the interday precision was expressed as the RSD of the aldehydes ranging from 6.6 to 8.4%. Matrix effects were shown to be negligible by comparing the response factors obtained in ultrapure and treated waters. Aldehydes were readily determined at 1.1–8.4 μg/L levels in ozonated and chlorinated water samples, the method proposed being the first CE contribution developed for the systematic analysis of both aliphatic and aromatic LMMAs in water samples.
The development of a counterflow‐assisted preconcentration technique in capillary electrophoresis electrospray‐ionization mass spectrometry
Authors: Wang Che‐Wei , Her Guor‐Rong
Published: December 2013

A preconcentration approach for CE‐MS using counterflow‐assisted electrokinetic injection was proposed. The proposed preconcentration method was based on a counterflow‐compatible sheathless interface. The interface was fabricated using a capillary‐assembled PDMS microdevice that allowed the application of a counterflow and provided liquid‐film electrical conduction. During electrokinetic injection, a hydrodynamic counterflow was introduced into the separation capillary to retard the movement of the stacking boundary to the CE outlet. Accordingly, a long injection time was achieved without a loss of CE separation. With the use of reverse polarity mode and a dynamic polybrene‐coated separation capillary (filled with a 1% formic acid solution), a counterflow‐assisted electrokinetic injection of peptide samples (in a aqueous solution containing 1% ammonia and 50% methanol) for 10 min provided a sensitivity enhancement of 750–1480 and a detection limit of 20 pM for the five peptide standards. The proposed technique was applied to the analysis of low nanomolar concentrations myoglobin tryptic peptides.
Simultaneous analysis of reduced glutathione and glutathione disulfide by capillary zone electrophoresis
Authors: Hempe James M. , Ory‐Ascani Jeannine
Published: December 2013

This report describes modifications to a CZE method developed by Serru et al. (Clinical Chemistry 2001, 47, 1321–1324) for the simultaneous analysis of reduced glutathione (GSH) and glutathione disulfide (GSSG). Lowering the pH of the run buffer (75 mmol/L boric acid, 25 mmol/L bis‐Tris) from pH 8.4 to 7.8 markedly improved GSH peak area reproducibility and allowed multiple samples to be analyzed without changing run buffers due to ion depletion. Sample preparation using red blood cells (RBC) instead of whole blood, combined with glutathione extraction at a lower concentration of metaphosphoric acid (5%), increased assay sensitivity and decreased interference. CZE assay results for clinical samples containing 1000 to 3200 μmol GSH/L RBC and 100 to 400 μmol GSSG/L RBC were highly correlated (r2 ≥ 0.95) with results obtained using a commercial dithionitrobenze‐based glutathione assay. The modified CZE assay has proven useful for the analysis of glutathione in both mouse and human RBC.
Separation and quantification of RNA molecules using size‐exclusion chromatography hyphenated with inductively coupled plasma‐mass spectrometry
Authors: Fujii Shin‐ichiro , Inagaki Kazumi , Miyashita Shin‐ichi , Groombridge Alexander S. , Nagasawa Keisuke , Chiba Koichi , Takatsu Akiko
Published: December 2013

The hyphenation of SEC with ICP‐MS was successfully applied to RNA quantification. The developed method combines the separation technique for large biomolecules and element selective detection of ICP‐MS. The separation of RNA molecules was performed under the SEC condition without additive reagents such as salts to prevent the adhesion of RNA molecules on the column resin. Fragments of RNA, which were commercially available as a ladder marker solution and certified reference materials, were successfully separated and analyzed by measuring 31P+ with this method. RNA was quantified with good repeatability (RSD of peak area; 2.7%, n = 3) and linearity (R2 = 0.999) using a P standard solution as a calibrant. LOD and absolute detection limit of RNA were 6.7 μg/kg and 67 pg, respectively, which were equal to the values obtained by the analysis of a P standard solution. The accuracy of the proposed measurement was evaluated by measuring certified reference materials of RNA solutions for quantitative analysis (NMIJ CRM 6204‐a). The results obtained by this method agreed with the certified values within uncertainty. The proposed analysis method, which demonstrates good accuracy and high precision and is free from interference by nucleotide analogues, qualifies as a method of quality control for the RNA synthesis and extraction process.
Potential of vancomycin for the enantiomeric resolution of FMOC‐amino acids by capillary electrophoresis‐ion‐trap‐mass spectrometry
Authors: Sánchez‐Hernández Laura , Domínguez‐Vega Elena , Montealegre Cristina , Castro‐Puyana María , Marina María Luisa , Crego Antonio L.
Published: December 2013

The potential of the antibiotic vancomycin (VC) as chiral selector for the enantiomeric separation of amino acids by CE‐ESI‐MS/MS2 was investigated for the first time in this work. Derivatization of amino acids with FMOC‐Cl was carried out to enable their interaction with VC as well as the formation of precursor ions with larger m/z which were employed in MS2 experiments. The partial filling of a coated capillary was employed to avoid the loss in MS sensitivity originated by the introduction of VC in the ionization source. Under optimized conditions, the simultaneous enantiomeric separation and unequivocal identification of 17 amino acids (two of them being nonprotein amino acids) took place in about 20 min with LODs in the micromolar range.
Determination of melamine impurities by capillary zone electrophoresis with UV‐ and quadrupole time‐of‐flight mass spectrometric detection
Authors: Himmelsbach Markus , Thanh Vo Thuy Diep
Published: December 2013

A method based on CZE coupled to quadrupole TOF MS (Q‐TOF MS), which is suitable to analyze seven common melamine impurities is presented. MS compatible formic acid based BGEs with various concentrations of organic modifiers were investigated using UV detection to determine the best separation system regarding resolution and speed. The optimized BGE consisted of 350 mM formic acid with 10% ACN and migration times were <6 min. The detection limits were considerably improved when ESI MS was applied instead of UV detection. In addition the instrument allows quantification with good linearity and repeatability in the relevant concentration range. The analytical characteristics of the method were evaluated for melamine, guanylurea, diaminotriazine, ureidomelamine, guanlymelamine, melam, methylmelamine, and dimethylmelamine both with UV and MS detection. Several different melamine samples were analyzed und the determined impurity levels were in the range from 0.02 to 2.3%.
Highly sensitive capillary electrophoretic immunoassay of rheumatoid factor in human serum with gold nanoparticles enhanced chemiluminescence detection
Authors: Liu Yan‐ming , Mei Lin , Liu Ying‐ying , Zhou Min , Huang Ke‐jing , Chen Yong‐hong , Ren Shu‐wei
Published: December 2013

A new CE‐based immunoassay method for the determination of rheumatoid factor was developed using chemiluminescent reaction of luminol and hydrogen peroxide catalyzed by gold nanoparticles (AuNPs). In this method, AuNPs were synthesized and conjugated with anti‐RF (antibody, Ab) to form tagged Ab (AuNPs‐Ab, Ab*), which subsequently linked to limited amount of RF (antigen, Ag) to produce Ab*–Ag complex by a noncompetitive immunoreaction. AuNPs were used to label antibody and amplify chemiluminescent signal. Under the optimized conditions, the mixture of free Ab* and Ab*–Ag complex was well separated and detected. This method yields a wide linear range of 0.01–20 μg/mL with a correlation coefficient of 0.997, and the detection limit of RF reaches 5.95 ng/mL (ca. 6.0 pmol/L, S/N = 3). The proposed method was successfully applied for the quantification of RF in human sera from patients with rheumatoid arthritis. This highly sensitive and selective method could be developed into a promising and useful technique for biological molecules determination in clinical analysis.
Capillary electrophoresis of microbial aggregates
Authors: Dziubakiewicz Ewelina , Buszewski Bogusław
Published: December 2013

Uncontrolled aggregation of bacterial cells is a significant disadvantage of electrophoretic separations. Various aspects of the electrophoretic behavior of different strains of Gram‐positive Bacillus cereus, Bacillus subtilis, Sarcina lutea, Staphylococcus aureus(1), and Micrococcus luteus bacteria and Gram‐negative Escherichia coli bacteria were investigated in this study. Our findings indicate that bacteria can be rapidly analyzed by CZE with surface charge modification by calcium ions (Ca2+). Bound Ca2+ ions increase zeta potential to more than 2.0 mV and significantly reduce repulsive forces. Under the above conditions, bacterial cells create compact aggregates, and fewer high‐intensity signals are observed in electropherograms. The above can be attributed to the bridging effect of Ca2+ between bacterial cells. CE was performed to analyze bacterial aggregates in an isotachophoretic mode. A single peak was observed in the electropherogram.
Displacement limits and performance displacement profiles in support of direct displacement‐based seismic assessment of bridges
Authors: Cardone Donatello
Published: December 2013

Displacement limits and performance displacement profiles (PDPs) for the direct displacement‐based assessment of existing bridges are proposed. The PDPs are defined as the bridge inelastic deformed shapes associated with the attainment of selected damage states in some critical elements of the bridge. In the paper, displacement limits are provided for piers, abutments, joints, bearing devices and shear keys. Moreover, different approaches for the definition of the PDP are examined, including adaptive pushover analysis, effective modal analysis, and rational analysis of simplified bridge models. In the paper, the key aspects and modeling assumptions of the proposed direct displacement‐based assessment procedure are presented first. This is followed by some examples of application to typical Italian highway bridge configurations, differing in pier layout, deck type, and pier‐deck connections. Copyright © 2013 John Wiley & Sons, Ltd.
An analysis and numerical simulation of the performance of trained hospital staff using movement assist devices to evacuate people with reduced mobility
Authors: Hunt Aoife , Galea Edwin R. , Lawrence Peter J.
Published: December 2013

This paper describes work undertaken to quantify the performance of trained hospital staff in evacuating people with reduced mobility. Data were collected from 32 trials in which a test subject was evacuated through 11 floors of Ghent University Hospital using four commonly used movement assistance devices: stretcher, carry chair, evacuation chair and rescue sheet. Presented in the paper are performance results for both male and female assist teams, including device preparation time, horizontal speeds, vertical speeds and overtaking potential in stairwells. These data form the basis of the device performance evaluation presented in this paper. A comparative methodology is derived to assess the efficiency of the devices and enable performance differences to be established. Finally, the data collected are used in a numerical simulation of the evacuation of a ward, located on the 11th floor of a hospital, containing 28 non‐ambulant patients. The scenarios investigate the time required to evacuate the ward using each of the four assist devices, assuming only the day or night shift staff are available. Furthermore, the scenarios consider the performance of all‐male and all‐female handlers and also take into consideration the impact of fatigue on the handlers. Copyright © 2013 John Wiley & Sons, Ltd.
TBAF Promoted Formation of Symmetrical Trisulfides
Authors: Lach Slawomir , Witt Dariusz
Published: December 2013

We have developed a new method for the synthesis of functionalized symmetrical trisulfides based on (5,5‐dimethyl‐2‐thioxo‐1,3,2‐dioxa‐phosphorin‐2‐yl)disulfanyl derivatives prepared from readily available 5,5‐dimethyl‐2‐sul‐fanyl‐2‐thioxo‐1,3,2‐dioxaphosphorinane or bis(5,5‐dimethyl‐2‐thioxo‐1,3,2‐dioxaphosphorinan‐2‐yl) disulfide. The symmetrical trisulfides can be obtained from aliphatic and aromatic thiols and l‐cysteine derivatives under mild conditions with high yield and purity.