bluuebunny/crossref_metadata_2025 huggingface dataset:
Cylindrical Data
Authors: Anderson‐cook Christine M. , Sango Otieno B.
Published: January 2013

Cylindrical data are a form of directional data, where two responses are considered. An angular or circular response is combined with a linear response to form observations, which can be thought of as a location in polar coordinates or on the surface of a unit cylinder. There are several alternatives for modeling the responses including circular‐linear relationships. Depending on the nature of the relationship between the two responses, some model forms can be more natural than others. Environmental examples of cylindrical data include plant and animal migration, as well as wind direction with another environmental measure such as ozone concentration or temperature.
Panarchy
Authors: Garmestani Ahjond S. , Allen Craig R.
Published: January 2013

Panarchy is the term coined to describe hierarchical systems where control is not only top down, as typically considered, but also bottom up. A panarchy is composed of adaptive cycles, and an adaptive cycle describes the processes of development and decay in a system. Complex systems self‐organize into hierarchies because this structure limits the possible spread of destructive phenomena (e.g., forest fires, epidemics) that could result in catastrophic system failure. Thus, hierarchical organization enhances the resilience of complex systems.
R and S
Authors: Wickham Hadley
Published: January 2013

R is a programming language and an environment for interactive data analysis. The first version of R was released in 1993, growing out of the S language developed at Bell Labs in the late 70s. The main strength of R is its rich ecosystem, which includes commercial vendors, thousands of add‐on packages, mechanisms for getting help, and many avenues for scientific publishing.
Power Analysis
Authors: Conn Paul B.
Published: January 2013

Power analysis is a tool for investigating trade‐offs between error rates, sample size, and precision, and has several different connotations depending on the underlying problem or objective. In the hypothesis testing context, power analysis can be used to investigate trade‐offs between Type I and Type II errors or to investigate the effect of varying sample size on statistical power. Power analysis has a broader definition in the context of environmental statistics, however, being widely used by statisticians to examine trade‐offs when designing sampling programs. In this context, power analysis largely refers to the allocation of survey effort in relation to some desired level of precision. The investigator might compare the effects of different design options (e.g., simple random sampling, stratified random sampling) or different types of estimators (model‐based estimators versus design‐based estimators). Power analysis is best viewed as a prospective tool for optimizing study design to meet objectives with a given set of constraints. In contrast, retrospective power analyses, whereby researchers fail to achieve a “significant” result and argue that it was likely due to insufficient sample size, are flawed and should be avoided.
S
ensitivity
A
nalysis of
S
tatistical
M
odels
Authors: Fassò Alessandro
Published: January 2013

Sensitivity analysis of statistical models is aimed here at finding influential observations that affect the model considered.

In this article, using the so‐called influence curve, a number of techniques are presented for assessing the sensitivity to a single or a group of data in regression analysis, time series, and spatiotemporal models.
Using Personal Landmark Events Improves Judgments about Time, but not Contents, in Autobiographical Memory
Authors: Zwartz Micaiah , Sharman Stefanie J.
Published: January 2013

Landmark events are strong memories that function as reference points for other memories. We examined whether people's accuracy in recalling when an earlier target event occurred was related to whether they spontaneously used personal landmark events or not. Participants completed two questionnaires separated by 2‐31 days. In the first, they described a personal event including what happened, who was there, where it was, and when it occurred. In the second questionnaire, they recalled the personal event and specific details. They also described whether they had used landmark events to assist their recall. Overall, participants' memories for temporal and content information faded over time. Spontaneous use of landmark events was associated with an increase in participants’ recall of temporal information but not content information. Analysis of the landmark events revealed that almost two‐thirds were significant events, such as birthdays, parties, and travel‐related events. Applications of the findings are discussed. Copyright © 2013 John Wiley & Sons, Ltd.
Guanidine‐Catalyzed Triple Functionalization of γ‐Substituted Allenoates with Aldehydes by a Four‐Step Reaction Cascade
Authors: Selig Philipp , Turočkin Aleksej , Raven William
Published: January 2013

The bicyclic guanidine 1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene (TBD) was discovered as an efficient catalyst for the reaction of γ‐substituted allenoates with aromatic aldehydes. 4H‐1,3‐Dioxin‐6‐ylpropanoates with four newly formed bonds and four stereogenic centers were obtained in good yields and excellent diastereoselectivities by two consecutive Morita–Baylis–Hillman reactions, acetalization and intramolecular Michael addition. This four‐step reaction cascade not only significantly expands the scope of catalytic allenoate functionalizations but also highlights the potential of TBD to act as a multifunctional Lewis base catalyst.
Shear properties and load–deflection response of cross–ply glass–epoxy composite short–beams subjected to three‐point‐bending tests, and the effect of moisture absorption
Authors: Sideridis Emilio P. , Bikakis George S.
Published: January 2013

The extensive use of composites in aerospace, chemical, marine, and structural applications leads to exposure to humidity and water immersion. Hence, there is a need to study the effect of moisture absorption on the mechanical properties of composite materials, especially the matrix dominated properties, such as the interlaminar shear strength (ILSS). The horizontal shear test with a short‐beam specimen in three‐point‐bending is used as a general method of evaluation for the shear properties in fiber‐reinforced composites because of its simplicity. In this work, the ILSS of cross‐ply glass‐epoxy resin composites is determined in seven different fiber directions with short‐beam three‐point‐bending tests, before and after moisture conditioning. It is found that moisture absorption reduces ILSS and stiffness of the examined composites whereas it leads to larger failure deflections. It is also found that the direction of fibers strongly affects the load–deflection response and the ILSS of the dry and conditioned specimens. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Effect of particle size and content of magnesium hydroxide on flame retardant properties of asphalt
Authors: Ren Fan , Zhang Xiaojiao , Wei Zheng , Chen Junfeng , Dong Dawei , Li Xiaolin , Zhang Liqun
Published: January 2013

The flame‐retardant properties of asphalt for some building applications are very important. This article is mainly focused on the influence of particle size and content of magnesium hydroxide (MH) on the flame‐retardant properties of asphalt. The limit oxygen index and cone calorimeter results indicate that as the MH content and mesh number increase, the flame‐retardant properties of MH‐filled flame‐retardant asphalt show a rising trend. But the role of particle size in smoke suppression is not obvious. Several tests confirm that the dispersion of the MH have some influence on the flame‐retarding effect of asphalt. The 3000 mesh MH for the preparation of flame‐retardant asphalt shows optimal performance. The experimental data show that the softening point of flame‐retardant asphalt increases, but the ductility and penetration decrease with increasing MH content. MH affects the asphalt viscosity, but not affects the adhesion of the asphalt to gravel. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Gpc‐Based Self‐Tuning PI Controller for Speed Servo System of PMSLM
Authors: Lu Shaowu , Tang Xiaoqi , Song Bao , Zheng Shiqi
Published: January 2013

In this paper, a generalized predictive control (GPC)‐based two degrees of freedom (2 DOF) proportional integral (PI) controller is proposed for the speed servo system of a permanent magnet synchronous linear motor (PMSLM). In this new approach, based on a dynamic model of a servo system, a simplified and high‐performance GPC supplies a 2 DOF PI controller with suitable control parameters, according to the varied operating conditions. In previous studies, GPC‐based proportional integral derivative (PID) controllers have been designed using a step‐type or ramp‐type reference input. In our work, however, the speed command for PMSLM usually is required to be a trapezium‐type signal because of the limited travel range. Hence, control performance of a speed servo system using a GPC‐based 2 DOF PI controller is enhanced for tracking a trapezium‐type command. The validity and usefulness of the proposed controller are verified through simulation and experiments.
Robust Adaptive Output‐Feedback Dynamic Surface Control of a Class of Nonlinear Systems with Unmodeled Dynamics
Authors: Song Mingchao , Lin Yan
Published: January 2013

This paper presents a robust adaptive output‐feedback dynamic surface control (DSC) for a class of nonlinear systems with unmodeled dynamics or/and uncertain time‐varying disturbances. Based on traditional K‐filters, the proposed adaptive DSC scheme is able to guarantee semi‐global stability of the closed‐loop system without applying any approximation techniques. The adaptive law is necessary only at the first design step, which, together with the introduction of a first‐order filter at each design step, makes the control law easy to implement. Moreover, it is shown that the tracking error can converge to an arbitrarily small residual set by adjusting only one design parameter.
Comparison of membrane electroporation and protein denature in response to pulsed electric field with different durations
Authors: Huang Feiran , Fang Zhihui , Mast Jason , Chen Wei
Published: January 2013

In this paper, we compared the minimum potential differences in the electroporation of membrane lipid bilayers and the denaturation of membrane proteins in response to an intensive pulsed electric field with various pulse durations. Single skeletal muscle fibers were exposed to a pulsed external electric field. The field‐induced changes in the membrane integrity (leakage current) and the Na channel currents were monitored to identify the minimum electric field needed to damage the membrane lipid bilayer and the membrane proteins, respectively. We found that in response to a relatively long pulsed electric shock (longer than the membrane intrinsic time constant), a lower membrane potential was needed to electroporate the cell membrane than for denaturing the membrane proteins, while for a short pulse a higher membrane potential was needed. In other words, phospholipid bilayers are more sensitive to the electric field than the membrane proteins for a long pulsed shock, while for a short pulse the proteins become more vulnerable. We can predict that for a short or ultrashort pulsed electric shock, the minimum membrane potential required to start to denature the protein functions in the cell plasma membrane is lower than that which starts to reduce the membrane integrity. Bioelectromagnetics 34:253–263, 2013. © 2012 Wiley Periodicals, Inc.
Continuous exposure to low amplitude extremely low frequency electrical fields characterizing the vascular streaming potential alters elastin accumulation in vascular smooth muscle cells
Authors: Bergethon Peter R. , Kindler Dean D. , Hallock Kevin , Blease Susan , Toselli Paul
Published: January 2013

In normal development and pathology, the vascular system depends on complex interactions between cellular elements, biochemical molecules, and physical forces. The electrokinetic vascular streaming potential (EVSP) is an endogenous extremely low frequency (ELF) electrical field resulting from blood flowing past the vessel wall. While generally unrecognized, it is a ubiquitous electrical biophysical force to which the vascular tree is exposed. Extracellular matrix elastin plays a central role in normal blood vessel function and in the development of atherosclerosis. It was hypothesized that ELF fields of low amplitude would alter elastin accumulation, supporting a link between the EVSP and the biology of vascular smooth muscle cells. Neonatal rat aortic smooth muscle cell cultures were exposed chronically to electrical fields characteristic of the EVSP. Extracellular protein accumulation, DNA content, and electron microscopic (EM) evaluation were performed after 2 weeks of exposure. Stimulated cultures showed no significant change in cellular proliferation as measured by the DNA concentration. The per‐DNA normalized protein in the extracellular matrix was unchanged while extracellular elastin accumulation decreased 38% on average. EM analysis showed that the stimulated cells had a 2.85‐fold increase in mitochondrial number. These results support the formulation that ELF fields are a potential factor in both normal vessel biology and in the pathogenesis of atherosclerotic diseases including heart disease, stroke, and peripheral vascular disease. Bioelectromagnetics 34:358–365, 2013. © 2012 Wiley Periodicals, Inc.
Blood stem cell products: Toward sustainable benchmarks for clinical translation
Authors: Csaszar Elizabeth , Cohen Sandra , Zandstra Peter W.
Published: January 2013

Robust ex vivo expansion of umbilical cord blood (UCB) derived hematopoietic stem and progenitor cells (HSPCs) should enable the widespread use of UCB as a source of cells to treat hematologic and immune diseases. Novel approaches for HSPC expansion have recently been developed, setting the stage for the production of blood stem cell derived products that fulfill our current best known criteria of clinical relevance. Translating these technologies into clinical use requires bioengineering strategies to overcome challenges of scale‐up, reproducibility, and product quality assurance. Clinical‐scale implementation should also define criteria and targets for cost‐effective cell manufacturing. As production strategies become more effective, new opportunities in the therapeutic use of ex vivo expanded hematopoietic cell products will emerge. Herein we examine key technological milestones that need to be met in order to move ex vivo expanded HSPC therapies from the bench‐top to the bedside in a robust and reliable manner.
BioEssays 2/2013
Authors: Fang Wenwen , Landweber Laura F.
Published: January 2013

RNA's role in genome rearrangement. Ciliated protists, such as Oxytricha, shown, have two types of nuclei that differentiate from each other. Development in these microbial eukaryotes provides a paragon for studies of genome remodeling, with extensive use of non‐coding RNAs. On pages 84–87 of this issue, Wenwen Fang and Laura Landweber discuss how RNA‐guided processes of genome rearrangement or repair could influence other eukaryotes. Cover by Wenyi Fang. SEM images courtesy of Robert Hammersmith.
Development of a rapid and high‐performance chemiluminescence immunoassay based on magnetic particles for protein S100B in human serum
Authors: Zhang Huisheng , Qi Suwen , Rao Jie , Li Qiaoliang , Yin Li , Lu Yuejun
Published: January 2013

Protein S100B is a clinically useful non‐invasive biomarker for brain cell damage. A rapid chemiluminescence immunoassay (CLIA) for S100B in human serum has been developed. Fluorescein isothiocyanate (FITC) and N‐(aminobutyl)‐N‐(ethylisoluminol) (ABEI) are used to label two different monoclonal antibodies of anti‐S100B. Protein S100B in serum combines with labeled antibodies and can form a sandwiched immunoreaction. A simplified separation procedure based on the use of magnetic particles (MPs) that were coated with anti‐FITC antibody is performed to remove the unwanted materials. After adding the substrate solution, the relative light unit (RLU) of ABEI is measured and is found to be directly proportional to the concentration of S100B in serum. The relevant variables involved in the CLIA signals are optimized and the parameters of the proposed method are evaluated. The results demonstrate that the method is linear to 25 ng/mL S100B with a detection limit of 0.02 ng/mL. The coefficient of variation (CV) is < 5% and < 6% for intra‐ and interassay precision, respectively. The average recoveries are between 97 and 107%. The linearity–dilution effect produces a linear correlation coefficient of 0.9988. Compared with the commercial kit, the proposed method shows a correlation of 0.9897. The proposed method displays acceptable performance for quantification of S100B and is appropriate for use in clinical diagnosis. Copyright © 2013 John Wiley & Sons, Ltd.
Superoxide anion radical scavenging property of catecholamines
Authors: Kładna Aleksandra , Berczyński Paweł , Kruk Irena , Michalska Teresa , Aboul‐Enein Hassan Y.
Published: January 2013

The direct effect of the four catecholamines (adrenaline, noradrenaline, dopamine and isoproterenol) on superoxide anion radicals () was investigated. The reaction between 18‐crown‐6‐ether and potassium superoxide in dimethylsulfoxide was used as a source of . The reactivity of catecholamines with was examined using chemiluminescence, reduction of nitroblue tetrazolium and electron paramagnetic resonance spin‐trapping techniques. 5,5‐Dimethyl‐1‐pyrroline‐N‐oxide was included as the spin trap. The results showed that the four catecholamines were effective and efficient in inhibiting chemiluminescence accompanying the potassium superoxide/18‐crown‐6‐ether system in a dose‐dependent manner over the range 0.05–2 mm in the following order: adrenaline > noradrenaline > dopamine > isoproterenol, with, IC50 = 0.15 ± 0.02 mm 0.21 ± 0.03 mm, 0.27 ± 0.03 mm and 0.50 ± 0.04 mm, respectively. The catecholamines examined also exhibited a strong scavenging effect towards when evaluated this property by the inhibition of nitroblue tetrazolium reduction (56–73% at 1 m concentration). A very similar capacity of scavenging was monitored in the 5,5‐dimethyl‐1‐pyrroline‐N‐oxide spin‐trapping assay. The results suggest that catecholamines tested may involve a direct effect on scavenging radicals. Copyright © 2013 John Wiley & Sons, Ltd.
Monitoring anaerobic sequential batch reactors via fractal analysis of pH time series
Authors: Méndez‐Acosta H.O. , Hernandez‐Martinez E. , Jáuregui‐Jáuregui J.A. , Alvarez‐Ramirez J. , Puebla H.
Published: January 2013

Efficient monitoring and control schemes are mandatory in the current operation of biological wastewater treatment plants because they must accomplish more demanding environmental policies. This fact is of particular interest in anaerobic digestion processes where the availability of accurate, inexpensive, and suitable sensors for the on‐line monitoring of key process variables remains an open problem nowadays. In particular, this problem is more challenging when dealing with batch processes where the monitoring strategy has to be performed in finite time, which limits the application of current advanced monitoring schemes as those based in the proposal of nonlinear observers (i.e., software sensors). In this article, a fractal time series analysis of pH fluctuations in an anaerobic sequential batch reactor (AnSBR) used for the treatment of tequila vinasses is presented. Results indicated that conventional on‐line pH measurements can be correlated with off‐line determined key process variables, such as COD, VFA and biogas production via some fractality indexes. Biotechnol. Bioeng. 2013; 110: 2131–2139. © 2013 Wiley Periodicals, Inc.
Comparison of three lymph node staging schemes for predicting outcome in patients with gastric cancer
Authors: Wang X , Appleby D-H , Zhang X , Gan L , Wang J-J , Wan F
Published: January 2013

Background

Several node staging schemes have been proposed for gastric cancer. The optimal system remains controversial.

Methods

Patients with gastric cancer were identified from the Surveillance, Epidemiology, and End Results (SEER) database, and a Chinese patient cohort was used for independent validation. The prognostic performance of three node staging schemes was compared, involving a number-based scheme (pN), ratio-based scheme (rN) and log odds of positive lymph nodes scheme (LODDS).

Results

There were 12 443 patients in the SEER database and 866 in the Chinese cohort. LODDS provided better discriminatory capacity and higher predictive accuracy than either pN or rN, for patients with gastric cancer in both the SEER database and the Chinese cohort. The multivariable model using the LODDS classification was significantly more predictive than the pN classification. LODDS suffered much less from stage migration and was able efficiently to discriminate the heterogeneity for patients with no nodes involved or all nodes involved, whereas the pN and rN schemes could not.

Conclusion

LODDS showed a clear prognostic superiority over both pN and rN schemes. It could serve as an important reference for the tumour node metastasis (TNM) node classification.
Rapid identification of primary constituents in parotoid gland secretions of the Australian cane toad using HPLC/MS‐Q‐TOF
Authors: Jing Jing , Ren Wei C. , Li Chun , Bose Utpal , Parekh Harendra S. , Wei Ming Q.
Published: January 2013

Toad parotoid gland secretion or toad venom has in recent years been increasingly shown to possess potentially beneficial pharmacological effects; this speculation has drawn much interest centred on elucidating the chemical basis of its multimodal effects. For this purpose, we explored the use of a rapid and accurate analysis method for systemic investigation of the parotoid gland chemistry, when extracted from Australian cane toads. Full‐scan data of cane toad venom extract was acquired using high‐performance liquid chromatography coupled with a hybrid quadrupole–time of flight mass spectrometry system (HPLC/MS‐Q‐TOF), with multiple ionization sources (ESI and APCI) in positive and negative mixed modes. By measuring the exact mass differences between the theoretical and measured mass of each assumed compound, we confirmed the presence of 12 key constituents. The present results demonstrate that the use of HPLC/MS‐Q‐TOF with multiple ionization sources delivers exemplary selectivity and sensitivity, allowing for the rapid and accurate identification of constituents within cane toad venom. This paves the way for this technique to be used in future routine screening of components within the genus Bufo and for key analytes too, then reliably assessed for any purported beneficial (clinic) properties. Copyright © 2013 John Wiley & Sons, Ltd.
PEGylated human plasma fibronectin is proteolytically stable, supports cell adhesion, cell migration, focal adhesion assembly, and fibronectin fibrillogenesis
Authors: Zhang Chen , Hekmatfar Sogol , Ramanathan Anand , Karuri Nancy W.
Published: January 2013

Delayed wound healing in many chronic wounds has been linked to the degradation of fibronectin (FN) by abnormally high protease levels. We sought to develop a proteolytically stable and functionally active form of FN. For this purpose, we conjugated 3.35 kDa polyethylene glycol diacrylate (PEGDA) to human plasma fibronectin (HPFN). Conjugation of PEGDA to HPFN or HPFN PEGylation was characterized by an increase of approximately 16 kDa in the average molecular weight of PEGylated HPFN compared to native HPFN in SDS‐PAGE gels. PEGylated HPFN was more resistant to α chymotrypsin or neutrophil elastase digestion than native HPFN: after 30 min incubation with α chymotrypsin, 56 and 90% of native and PEGylated HPFN respectively remained intact. PEGylated HPFN and native HPFN supported NIH 3T3 mouse fibroblast adhesion and spreading, migration and focal adhesion formation in a similar manner. Fluorescence microscopy showed that both native and PEGylated HPFN in the culture media were assembled into extracellular matrix (ECM) fibrils. Interestingly, when coated on surfaces, native but not PEGylated HPFN was assembled into the ECM of fibroblasts. The proteolytically stable PEGylated HPFN developed herein could be used to replenish FN levels in the chronic wound bed and promote tissue repair. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29: 493–504, 2013
Efficiency of different heterologous promoters in the unicellular microalga Chlamydomonas reinhardtii
Authors: Díaz‐Santos Encarnación , de la Vega Marta , Vila Marta , Vigara Javier , León Rosa
Published: January 2013

Despite the biotechnological interest of microalgae, no robust and stable methods for genetic transformation of most microalgal strains exist. The scanty and disperse data about the efficiency of heterologous promoters in microalgae and the use of different transformation methods, DNA quantities and reporter genes in the existing studies makes very difficult a real comparison of their efficiency. Using Chlamydomonas reinhardtii as a host, we have evaluated the efficiency of the heterologous promoters of cauliflower mosaic virus 35S (CaMV 35S) and Agrobacterium nopaline synthase (NOS) genes. These promoters were fused to the paromomycin conferring‐resistance aminoglycoside 3′‐phosphotransferase encoding gene (APHVIII), and C. reinhardtii was transformed by the glass beads agitation method. The transformation efficiency and the APHVIII transcript and protein levels were evaluated in a series of transformants for each promoter. The chimeric promoter HSP70A/RBCS2 and the promoter‐less APHVIII marker gene were used for comparison. We found significantly higher transformation efficiencies and higher level of APHVIII expression in those transformants harboring the NOS promoter than in those transformed with CaMV 35S promoter. The NOS promoter, widely used for genetic manipulation of higher plants, has been very rarely used for the transformation of microalgae. The results shown here suggest the possibilities of this heterologous promoter as an efficient system for the genetic manipulation of microalgae. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29: 319–328, 2013
Gas‐Phase Reactions of Cationic Vanadium‐Phosphorus Oxide Clusters with C2Hx (x=4, 6): A DFT‐Based Analysis of Reactivity Patterns
Authors: Dietl Nicolas , Zhang Xinhao , van der Linde Christian , Beyer Martin K. , Schlangen Maria , Schwarz Helmut
Published: January 2013

The reactivities of the adamantane‐like heteronuclear vanadium‐phosphorus oxygen cluster ions [VxP4−xO10].+ (x=0, 2–4) towards hydrocarbons strongly depend on the V/P ratio of the clusters. Possible mechanisms for the gas‐phase reactions of these heteronuclear cations with ethene and ethane have been elucidated by means of DFT‐based calculations; homolytic CH bond activation constitutes the initial step, and for all systems the PO. unit of the clusters serves as the reactive site. More complex oxidation processes, such as oxygen‐atom transfer to, or oxidative dehydrogenation of the hydrocarbons require the presence of a vanadium atom to provide the electronic prerequisites which are necessary to bring about the 2e− reduction of the cationic clusters.
Nitrogen‐Doped Carbon Dots: A Facile and General Preparation Method, Photoluminescence Investigation, and Imaging Applications
Authors: Xu Yang , Wu Ming , Liu Yang , Feng Xi‐Zeng , Yin Xue‐Bo , He Xi‐Wen , Zhang Yu‐Kui
Published: January 2013

Carbon dots (Cdots) are an important probe for imaging and sensing applications because of their fluorescence property, good biocompatibility, and low toxicity. However, complex procedures and strong acid treatment are often required and Cdots suffer from low photoluminescence (PL) emission. Herein, a facile and general strategy using carbonization of precursors and then extraction with solvents is proposed for the preparation of nitrogen‐doped Cdots (N‐Cdots) with 3‐(3,4‐dihydroxyphenyl)‐L‐alanine (L‐DOPA), L‐histidine, and L‐arginine as precursor models. After they are heated, the precursors become carbonized. Nitrogen‐doped Cdots are subsequently extracted into N,N′‐dimethylformamide (DMF) from the carbogenic solid. A core–shell structure of Cdots with a carbon core and the oxygen‐containing shell was observed. Nitrogen has different forms in N‐Cdots and oxidized N‐Cdots. The doped nitrogen and low oxidation level in N‐Cdots improve their emission significantly. The N‐Cdots show an emission with a nitrogen‐content‐dependent intensity and Cdot‐size‐dependent emission‐peak wavelength. Imaging of HeLa cells, a human cervical cancer cell line, and HepG2 cells, a human hepatocellular liver carcinoma line, was observed with high resolution using N‐Cdots as a probe and validates their use in imaging applications and their multicolor property in the living cell system.
Retinoic acid promotes the development of Arg1‐expressing dendritic cells for the regulation of T‐cell differentiation
Authors: Chang Jinsam , Thangamani Shankar , Kim Myung H. , Ulrich Benjamin , Morris Sidney M. , Kim Chang H.
Published: January 2013

Arginase I (Arg1), an enzyme expressed by many cell types including myeloid cells, can regulate immune responses. Expression of Arg1 in myeloid cells is regulated by a number of cytokines and tissue factors that influence cell development and activation. Retinoic acid, produced from vitamin A, regulates the homing and differentiation of lymphocytes and plays important roles in the regulation of immunity and immune tolerance. We report here that optimal expression of Arg1 in DCs requires retinoic acid. Induction of Arg1 by retinoic acid is directly mediated by retinoic acid‐responsive elements in the 5′ noncoding region of the Arg1 gene. Arg1, produced by DCs in response to retinoic acid, promotes the generation of FoxP3+ regulatory T (Treg) cells. Importantly, blocking the retinoic acid receptor makes DCs hypo‐responsive to known inducers of Arg1 such as IL‐4 and GM‐CSF in Arg1 expression. We found that intestinal CD103+ DCs that are known to produce retinoic acid highly express Arg1. Our results establish retinoic acid as a key signal in expression of Arg1 in DCs.
NK cells from pleural effusions are potent antitumor effector cells
Authors: Terme Magali , Fridman Wolf Hervé , Tartour Eric
Published: January 2013

Natural killer (NK) cells express a set of activating and inhibitory receptors which, after interaction with their ligands, determine whether or not the target cell will be lysed. Many studies have clearly demonstrated that NK cells have the capacity to lyse stressed cells (such as tumor or virally‐infected cells). However, NK cells that infiltrate tumors usually exhibit phenotypic and functional defects. In this issue of the European Journal of Immunology, Vacca et al. [Eur. J. Immunol. 2013. 43: 550‒561] show that NK cells in pleural effusions of primary and metastatic tumors of various origins are not anergic, possibly because the downregulation of activating receptors and the upregulation of inhibitory receptors does not occur, as previously reported for tumor NK cells. Another major finding of this study is the capacity of these pleural NK cells to respond to IL‐2 stimulation, as the authors demonstrate that pleural NK cells stimulated by IL‐2 in long‐term culture acquire the capacity to lyse autologous tumor cells isolated from pleural effusions. These results support the treatment of primary or metastatic pleural tumors with IL‐2 or other innovative strategies currently being developed to stimulate NK cells in cancer patients as discussed in this Commentary.
Two Enantiomorphic MgII/Carboxylate Coordination Polymers Produced from Spontaneous Resolution with an Achiral Bipyridyl Dicarboxylate Ligand
Authors: Zhang Qingfu , Hao Hongguo , Zhang Haina , Wang Suna , Jin Juan , Sun Dezhi
Published: January 2013

Two enantiomorphic MgII/carboxylate coordination polymers [Mg(bpda)(H2O)4]n (1M and 1P) have been obtained by spontaneous resolution from achiral precursors, 2,2′‐bipyridyl‐3,3′‐dicarboxylic acid (H2bpda) and Mg(NO3)2·6H2O, upon crystallization without any chiral auxiliary. X‐ray structural analysis shows that chiral transmission from molecular axially chiral conformations to crystal chirality is established through concerted coordination and H‐bonding interactions. In addition, the CD data, and the thermal and photoluminescence properties in the solid state have also been discussed.
Planar Chiral Triazole‐Based Phosphanes Derived from [2.2]Paracyclophane and Their Activity in Suzuki Coupling Reactions
Authors: Glover Jean E. , Martin David J. , Plieger Paul G. , Rowlands Gareth J.
Published: January 2013

In this communication we report the short synthesis of a variety of planar chiral triazole‐based phosphanes. These molecules have been readily prepared from 4‐azido[2.2]paracyclophane in two steps. It was observed that the stability of the resulting phosphanes was dependent on the C‐4 substituent. The efficacy of the new phosphanes in the palladium‐mediated Suzuki–Miyaura coupling reaction was evaluated. The phosphanes proved to be more effective than previously prepared planar chiral [2.2]paracyclophane‐based phosphanes.
Exploring Properties of a Hyperthermophilic Membrane‐Bound Hydrogenase at Carbon Nanotube Modified Electrodes for a Powerful H2/O2 Biofuel Cell
Authors: De Poulpiquet Anne , Ciaccafava Alexandre , Szot Katarzyna , Pillain Baptiste , Infossi Pascale , Guiral Marianne , Opallo Marcin , Giudici‐Orticoni Marie‐Thérèse , Lojou Elisabeth
Published: January 2013

Hydrogenases are the key enzymes for hydrogen metabolism in many microorganisms. Due to the high efficiency and specificity they developed for H2 oxidation, they have been recently used as biocatalysts for an efficient H2/O2 biofuel cell. In this work we explore new properties of an O2‐, CO‐ and T°‐resistant hydrogenase. Enzyme immobilization on carbon nanotube modified electrodes is studied and optimized for long‐term stabilization of the direct hydrogen catalytic oxidation process. The role of co‐immobilized redox mediator is finally discussed in view of H2/O2 fuel cell performance enhancement.
Determination of Trichloroacetic Acid (TCAA) Using CdO Nanoparticles Modified Carbon Paste Electrode
Authors: Najafi Mostafa , Darabi Salman , Tadjarodi Azadeh , Imani Mina
Published: January 2013

In this paper, the electrochemical behavior of a carbon paste electrode modified with CdO nanoparticles as a potential electrocatalyst for the reduction of trichloroacetic acid (TCAA) was investigated using cyclic voltammetry and double‐potential step chronoamperometry. The modified electrode showed a great enhancement in cathodic peak current with respect to reduction of TCAA in acidic aqueous solution. Using this increment, a quantitative method was developed for the determination of TCAA in aqueous solution. The detection limit and linear dynamic range of TCAA are 2.3×10−6 M and 2.3×10−4–3×10−6 M, respectively.
Detection of Prunus Necrotic Ringspot Virus in Plant Extracts with Impedimetric Immunosensor based on Glassy Carbon Electrode
Authors: Jarocka Urszula , Radecka Hanna , Malinowski Tadeusz , Michalczuk Lech , Radecki Jerzy
Published: January 2013

This paper concerns the development of an immunosensor for detection of Prunus necrotic ringspot virus (PNRSV) in plant extracts. The immunosensor fabrication consists of successive modification steps of glassy carbon electrodes: (i) creation of COOH groups, (ii) covalent immobilization of protein A with EDC/NHS coupling reaction, (iii) immobilization of anti‐PNRSV IgG polyclonal antibody, (iiii) filling free spaces with BSA. Each step was controlled with cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The immunosensor was applied for the determination of the PNRSV virus in extracts from cucumber leaves using EIS technique. It was capable of discriminating between samples consisting of extracts from healthy plants and consisting of leaf extracts from infected plants diluted 10 000 times with extract from healthy plants.
Detection of Tellurium in Presence of Extra Arsenic on Gold Electrodes Modified By Benzenedithiol Self‐Assembled Monolayers
Authors: Bass Ethan , Ke Shan
Published: January 2013

Electrochemical detection of tellurium is interfered with arsenic due to their similar redox potentials. Gold electrodes modified by benzenedithiols (BDT) self‐assembled monolayers (SAMs) were explored to determine Te(IV) in the presence of extra As(III) in this work. SAMs of benzenedithiols on the gold surface allows for selective extraction of Te (IV) over As(III), while blocking the redox of As(III). It provides potential applications to tellurium toxicity analysis, biological membrane study and identification of geochemistry samples.
Cross-tolerance in amphibians: Wood frog mortality when exposed to three insecticides with a common mode of action
Authors: Hua Jessica , Cothran Rickey , Stoler Aaron , Relyea Rick
Published: January 2013

Insecticide tolerance and cross-tolerance in nontarget organisms is often overlooked despite its potential to buffer natural systems from anthropogenic influence. We exposed wood frog tadpoles from 15 populations to three acetylcholine esterase-inhibiting insecticides and found widespread variation in insecticide tolerance and evidence for cross-tolerance to these insecticides. Our results demonstrate that amphibian populations with tolerance to one pesticide may be tolerant to many other pesticides. Environ. Toxicol. Chem. 2013;32:932–936. © 2013 SETAC
Associations between perfluoroalkyl compounds and immune and clinical chemistry parameters in highly exposed bottlenose dolphins (Tursiops truncatus)
Authors: Fair Patricia A. , Romano Tracy , Schaefer Adam M. , Reif John S. , Bossart Gregory D. , Houde Magali , Muir Derek , Adams Jeff , Rice Charles , Hulsey Thomas C. , Peden-Adams Margie
Published: January 2013

Perfluoroalkyl compounds (PFCs) are ubiquitous, persistent chemical contaminants found in the environment, wildlife, and humans. Despite the widespread occurrence of PFCs, little is known about the impact these contaminants have on the health of wildlife populations. The authors investigated the relationship between PFCs (including ∑perfluorocarboxylates, ∑perfluoroalkyl sulfonates, perfluorooctane sulfonate, perfluorooctanoic acid, and perfluorodecanoic acid) and the clinocopathologic and immune parameters in a highly exposed population (n = 79) of Atlantic bottlenose dolphins (mean ∑PFCs = 1970 ng/ml; range 574–8670 ng/ml) sampled from 2003 to 2005 near Charleston, South Carolina, USA. Age-adjusted linear regression models showed statistically significant positive associations between exposure to one or more of the PFC totals and/or individual analytes and the following immunological parameters: absolute numbers of CD2+ T cells, CD4+ helper T cells, CD19+ immature B cells, CD21+ mature B cells, CD2/CD21 ratio, MHCII+ cells, B cell proliferation, serum IgG1, granulocytic, and monocytic phagocytosis. Several PFC analyte groups were also positively associated with serum alanine aminotransferase, gamma-glutamyltransferase, creatinine, phosphorus, amylase, and anion gap and negatively associated with cholesterol levels, creatinine phosphokinase, eosinophils, and monocytes. Based on these relationships, the authors suggest that the PFC concentrations found in Charleston dolphins may have effects on immune, hematopoietic, kidney, and liver function. The results contribute to the emerging data on PFC health effects in this first study to describe associations between PFCs and health parameters in dolphins. Environ. Toxicol. Chem. 2013;32:736–746. © 2013 SETAC
Predictive QSPR modelling for the olfactory threshold of a series of pyrazine derivatives
Authors: Pal Pallabi , Mitra Indrani , Roy Kunal
Published: January 2013

Nowadays, much interest is shown in the prediction of different organoleptic properties of molecules for their prominent use in a variety of formulations and food products. Against this background, cheminformatics modelling was done in the present work for the development of predictive models for the olfactory threshold (log T) of a series of 74 pyrazine derivatives employing in silico techniques such as genetic function algorithm (GFA) and genetic partial least squares algorithm (G/PLS). Different categories of descriptors were calculated for the work. After validating the models both internally and externally, a parabolic GFA‐spline model was selected as the best model which showed significant predictive quality [ = 0.822,
= 0.641,
= 0.019]. Interpretation of the descriptors concluded that increased hydrophobic surface area, along with an increase in the positive charge weighted solvent accessible surface area (as interpreted from the Jurs_DPSA_2 descriptor) in the molecules, provides a low value of log T. Again, the presence of an isopropyl group and electron richness of the molecules significantly influences the property profile (log T) of the molecules. Finally, 27 pyrazine derivatives were designed based on the present analysis and good in silico prediction values for odour threshold, i.e. low log T values were obtained from the developed model. Thus, use of this optimized quantitative structure–property relationship (QSPR) model may be used to screen molecule databases as well as modify the structures for selection of potent entities. Copyright © 2013 John Wiley & Sons, Ltd.
Analysis of hepatitis C virus resistance to silibinin in vitro and in vivo points to a novel mechanism involving nonstructural protein 4B
Authors: Esser-Nobis Katharina , Romero-Brey Inés , Ganten Tom M. , Gouttenoire Jérôme , Harak Christian , Klein Rahel , Schemmer Peter , Binder Marco , Schnitzler Paul , Moradpour Darius , Bartenschlager Ralf , Polyak Stephen J. , Stremmel Wolfgang , Penin François , Eisenbach Christoph , Lohmann Volker
Published: January 2013

Intravenous silibinin (SIL) is an approved therapeutic that has recently been applied to patients with chronic hepatitis C, successfully clearing hepatitis C virus (HCV) infection in some patients even in monotherapy. Previous studies suggested multiple antiviral mechanisms of SIL; however, the dominant mode of action has not been determined. We first analyzed the impact of SIL on replication of subgenomic replicons from different HCV genotypes

in vitro

and found a strong inhibition of RNA replication for genotype 1a and genotype 1b. In contrast, RNA replication and infection of genotype 2a were minimally affected by SIL. To identify the viral target of SIL we analyzed resistance to SIL

in vitro

and

in vivo
. Selection for drug resistance in cell culture identified a mutation in HCV nonstructural protein (NS) 4B conferring partial resistance to SIL. This was corroborated by sequence analyses of HCV from a liver transplant recipient experiencing viral breakthrough under SIL monotherapy. Again, we identified distinct mutations affecting highly conserved amino acid residues within NS4B, which mediated phenotypic SIL resistance also

in vitro
. Analyses of chimeric viral genomes suggest that SIL might target an interaction between NS4B and NS3/4A. Ultrastructural studies revealed changes in the morphology of viral membrane alterations upon SIL treatment of a susceptible genotype 1b isolate, but not of a resistant NS4B mutant or genotype 2a, indicating that SIL might interfere with the formation of HCV replication sites.

Conclusion:

Mutations conferring partial resistance to SIL treatment

in vivo

and in cell culture argue for a mechanism involving NS4B. This novel mode of action renders SIL an attractive candidate for combination therapies with other directly acting antiviral drugs, particularly in difficult-to-treat patient cohorts. (Hepatology 2013)
Decreased iron burden in overweight C282Y homozygous women: Putative role of increased hepcidin production
Authors: Desgrippes Romain , Lainé Fabrice , Morcet Jeff , Perrin Michèle , Manet Ghislain , Jezequel Caroline , Bardou-Jacquet Edouard , Ropert Martine , Deugnier Yves
Published: January 2013

An excess of visceral adipose tissue could be involved as a modulator of the penetrance of HFE hemochromatosis since fat mass is associated with overexpression of hepcidin and low transferrin saturation was found to be associated with being overweight in women. This study was aimed at assessing the relationship between body mass index (BMI), a surrogate marker of insulin resistance, and iron burden in HFE hemochromatosis. In all, 877 patients from a cohort of C282Y homozygotes were included in the study when BMI at diagnosis and amount of iron removed (AIR) by phlebotomy were available. No relationship between AIR and BMI was found in men, whereas 15.1% (52/345) of women with AIR <6 g had BMI ≥28 versus 3.9% (2/51) of women with AIR ≥6 g (

P

= 0.03). At multivariate analysis, BMI was an independent factor negatively associated with AIR (odds ratio: 0.13; 95% confidence interval [CI]: 0.03-0.71) together with serum ferritin, serum transferrin, transferrin saturation, hemoglobin, and alanine aminotransferase. In a control group of 30 C282Y homozygous women, serum hepcidin was significantly higher in overweight (14.3 mmoL/L ± 7.1) than in lean (7.9 mmoL/L ± 4.3) women (

P

= 0.0005).

Conclusion :

In C282Y homozygous women, BMI ≥28 kg/m2 is independently associated with a lower amount of iron removed by phlebotomy. BMI is likely a modulator factor of the phenotypic expression of C282Y homozygosity, likely through an increase of circulating levels of hepcidin. (Hepatology 2013;)
Identification of novel serum biomarkers of hepatocellular carcinoma using glycomic analysis
Authors: Kamiyama Toshiya , Yokoo Hideki , Furukawa Jun-Ichi , Kurogochi Masaki , Togashi Tomoaki , Miura Nobuaki , Nakanishi Kazuaki , Kamachi Hirofumi , Kakisaka Tatsuhiko , Tsuruga Yosuke , Fujiyoshi Masato , Taketomi Akinobu , Nishimura Shin-Ichiro , Todo Satoru
Published: January 2013

The altered

N

-glycosylation of glycoproteins has been suggested to play an important role in the behavior of malignant cells. Using glycomics technology, we attempted to determine the specific and detailed

N

-glycan profile for hepatocellular carcinoma (HCC) and investigate the prognostic capabilities. From 1999 to 2011, 369 patients underwent primary curative hepatectomy in our facility and were followed up for a median of 60.7 months. As normal controls, 26 living Japanese related liver transplantation donors were selected not infected by hepatitis B and C virus. Their mean age was 40.0 and 15 (57.7%) were male. We used a glycoblotting method to purify

N

-glycans from preoperative blood samples from this cohort (10 μL serum) which were then identified and quantified using mass spectrometry (MS). Correlations between the

N

-glycan levels and the clinicopathologic characteristics and outcomes for these patients were evaluated. Our analysis of the relative areas of all the sugar peaks identified by MS, totaling 67

N

-glycans, revealed that a proportion had higher relative areas in the HCC cases compared with the normal controls. Fourteen of these molecules had an area under the curve of greater than 0.80. Analysis of the correlation between these 14

N

-glycans and surgical outcomes by univariate and multivariate analysis identified G2890 (

m/z

value, 2890.052) as a significant recurrence factor and G3560 (

m/z

value, 3560.295) as a significant prognostic factor. G2890 and G3560 were found to be strongly correlated with tumor number, size, and vascular invasion.

Conclusion

: Quantitative glycoblotting based on whole serum

N

-glycan profiling is an effective approach to screening for new biomarkers. The G2890 and G3560

N

-glycans determined by tumor glycomics appear to be promising biomarkers for malignant behavior in HCCs.