bluuebunny/crossref_metadata_2025 huggingface dataset:
Biomarkers for Subtle Brain Dysfunction
Authors: Dambinova Svetlana A. , Gill SARAH , St. Onge Laura , Sowell Richard L.
Published: January 2017

The diagnosis of concussion is complicated because many primary impacts go unidentified or are not reported, especially when they are sports related, and there is often no loss of consciousness. Competitive athletes are also subjected to recurrent concussions; if left unrecognized, they may lead to potentially more debilitating, delayed second-impact injuries. In this chapter, we present recently obtained data concerning the possibility of post-concussion effect assessment in club sport athletes with semi-acute and chronic concussions by use of blood assays based on detection of neurotoxicity biomarkers.
Feasibility Studies of Neurotoxicity Biomarkers for Assessment of Traumatic Brain Injury
Authors: Shikuev Alexey V. , Skoromets Taras A. , Skulyabin Dmitri I. , Odinak Miroslav M. , Skoromets Alexander A.
Published: January 2017

This chapter is devoted to clinical feasibility studies: of (i) AMPAR peptide in assessment of patients with mild traumatic brain injury (TBI), (ii) predicting the risk of cerebrovascular accident after mild TBI using NMDAR peptide and antibodies, and (iii) AMPAR antibodies in evaluation of post-traumatic epilepsy in persons after moderate TBI. The data on patient cohorts in emergency department and military settings are described.
Future Trends in Biomarker Immunoassay Development
Authors: Dambinova Svetlana A. , Hayes Ronald L.
Published: January 2017

The evaluation of specific biomarkers for assessment of TBI and other neurological conditions, development of an immunoassay, and its translation to clinical laboratories are discussed. This chapter provides brief information concerning interrelations between assay development, clinical indications, regulatory restrictions, and future trends in drug/test co-development for TBI biomarkers. The strategy of biomarker assay adaptation to personalized medicine is outlined.
Selection of Analytical Methodology for Metabolomics
Authors: Wiedmer Susanne K. , Hyötyläinen Tuulia
Published: January 2017

The main challenge in metabolomics analysis is the separation, identification and quantification of a large number of known or unknown metabolites in complex samples. The correct selection of sample collection and preparation method, type of separation methodology and detection are all crucial steps in the analysis of metabolomics. This chapter provides an overview of and general guidelines for strategies involved in the analysis of metabolomics, and different chromatographic techniques used in metabolomics studies are briefly presented. The methods are compared and the main features of the separation methods are listed. Finally, general conclusions and future perspectives are provided.
Liquid identification by using a micro-electro-mechanical interdigital transducer
Authors: Bui ThuHang , Morana Bruno , Akhnoukh Atef , Chu Duc Trinh , Sarro Pasqualina M.
Published: January 2017

A surface-acoustic-mode aluminum nitride (AlN) transducer is utilized to determine the type of liquid dropped on the propagation path.
An LC-MS/MS method for the determination of 28 polar environmental contaminants and metabolites in vegetables irrigated with treated municipal wastewater
Authors: Riemenschneider Christina , Seiwert Bettina , Goldstein Myah , Al-Raggad Marwan , Salameh Elias , Chefetz Benny , Reemtsma Thorsten
Published: January 2017

An analytical method for the determination of wastewater-derived contaminants and possible metabolites in common plant tissues was developed and validated.
Probing the molecular determinants of fluorinase specificity
Authors: Yeo W. L. , Chew X. , Smith D. J. , Chan K. P. , Sun H. , Zhao H. , Lim Y. H. , Ang E. L.
Published: January 2017

Probing the structural determinants of fluorinase enzyme specificity with 5′-chloro-5′-deoxyadenosine (5′-ClDA) analog substrates generated fluorinases with improved and novel activity.
Firmly anchored photosensitizer Chlorin e6 to layered double hydroxide nanoflakes for highly efficient photodynamic therapy in vivo
Authors: Yan Li , Wang Zhigang , Chen Xianfeng , Gou Xiao-Jun , Zhang Zhenyu , Zhu Xiaoyue , Lan Minhuan , Chen Wei , Zhu Guangyu , Zhang Wenjun
Published: January 2017

We covalently conjugate photosensitizer Chlorin e6 (Ce6) to polyethylene glycol modified layered double hydroxides and produce hybrid nanoflakes with excellentin vivophotodynamic therapeutic efficiency and safety profiles.
A new approach to distance measurements between two spin labels in the >10 nm range
Authors: Blank A.
Published: January 2017

ESR spectroscopy can be efficiently used to acquire the distance between two spin labels placed on a macromolecule by measuring their mutual dipolar interaction frequency, as long as the distance is not greater than ∼10 nm.
Vibrational frequencies and spectroscopic constants of three, stable noble gas molecules: NeCCH+, ArCCH+, and ArCN+
Authors: Novak Carlie M. , Fortenberry Ryan C.
Published: January 2017

The search for possible, natural, noble gas molecules has led to quantum chemical, spectroscopic analysis of NeCCH+, ArCCH+, and ArCN+.
Recent developments in reversible photoregulation of oligonucleotide structure and function
Authors: Lubbe Anouk S. , Szymanski Wiktor , Feringa Ben L.
Published: January 2017

A critical overview is given of recent applications of molecular photoswitches to modulate DNA and RNA structure and function.
Tailored synthesis of nonlinear optical quaternary chalcohalides: Ba4Ge3S9Cl2, Ba4Si3Se9Cl2 and Ba4Ge3Se9Cl2
Authors: Liu Peng-Fei , Li Yan-Yan , Zheng Yu-Jun , Yu Ju-Song , Duan Rui-Huan , Chen Hong , Lin Hua , Chen Ling , Wu Li-Ming
Published: January 2017

Three nonlinear optical chalcohalides, Ba4Ge3S9Cl2, Ba4Si3Se9Cl2 and Ba4Ge3Se9Cl2, have been synthesized by a tailored synthetic approach based on [M3Q9]6− (M = Ge, Q = S; M = Si/Ge, Q = Se) building units.
Redox properties and electron transfer in a triarylamine-substituted HS-Co2+/LS-Co3+ redox couple
Authors: Schnaubelt Linda , Petzold Holm , Speck J. Matthäus , Dmitrieva Evgenia , Rosenkranz Marco , Korb Marcus
Published: January 2017

The redox and electron transfer properties of a triarylamine decorated HS-Co2+/LS-Co3+ redox couple were investigated by coupled EPR/UV-vis-NIR spectroelectrochemistry and 1H NMR spectroscopy.
Underscreening in concentrated electrolytes
Authors: Lee Alpha A. , Perez-Martinez Carla S. , Smith Alexander M. , Perkin Susan
Published: January 2017

Screening of a surface charge by an electrolyte and the resulting interaction energy between charged objects is of fundamental importance in scenarios from bio-molecular interactions to energy storage. The conventional wisdom is that the interaction energy decays exponentially with object separation and the decay length is a decreasing function of ion concentration; the interaction is thus negligible in a concentrated electrolyte. Contrary to this conventional wisdom, we have shown by surface force measurements that the decay length is an increasing function of ion concentration and Bjerrum length for concentrated electrolytes. In this paper we report surface force measurements to test directly the scaling of the screening length with Bjerrum length. Furthermore, we identify a relationship between the concentration dependence of this screening length and empirical measurements of activity coefficient and differential capacitance. The dependence of the screening length on the ion concentration and the Bjerrum length can be explained by a simple scaling conjecture based on the physical intuition that solvent molecules, rather than ions, are charge carriers in a concentrated electrolyte.
Aqueous hemin catalyzed sulfonium ylide formation and subsequent [2,3]-sigmatropic rearrangements
Authors: Xu Xiaofei , Li Chang , Tao Zhihao , Pan Yuanjiang
Published: January 2017

A mild and efficient strategy for the Doyle–Kirmse reaction is established and an unprecedented cascade C–H insertion is reported.
Simultaneous chromatographic purification of Si and Mg for isotopic analyses using MC-ICPMS
Authors: Sikdar Jinia , Rai Vinai K.
Published: January 2017

This study presents a chemical protocol for simultaneous purification of silicon and magnesium from a single aliquot of rock sample.
Addition of nitrogen dioxide to carbon–carbon double bond followed by a cyclization to construct nitromethylated isoquinolinediones
Authors: Li Xuanxuan , Zhuang Shengyi , Fang Xinxin , Liu Ping , Sun Peipei
Published: January 2017

4-(Nitromethyl)isoquinoline-1,3(2H,4H)-diones were synthesizedviaa tandem nitration/cyclization reaction ofN-alkyl-N-methacryloyl benzamides using CO2as the nitro source.
Dual gold and photoredox catalysed C–H activation of arenes for aryl–aryl cross couplings
Authors: Gauchot V. , Sutherland D. R. , Lee A.-L.
Published: January 2017

A mild and fully catalytic aryl–aryl cross coupling via gold-catalyzed C–H activation has been achieved by merging gold and photoredox catalysis.
Correction: Photoinduced electron transfer as a design concept for luminescent redox indicators
Authors: Magri David C.
Published: January 2017

Correction for ‘Photoinduced electron transfer as a design concept for luminescent redox indicators’ by David C. Magri, Analyst, 2015, 140, 7487–7495.
Hydrophosphination-type reactivity promoted by bismuth phosphanides: scope and limitations
Authors: Schwamm R. J. , Fulton J. R. , Coles M. P. , Fitchett C. M.
Published: January 2017

Hydrophosphination-type reactivity promoted by a bismuth(iii) phosphanide is reported.
Accurate representations of the physicochemical properties of atmospheric aerosols: when are laboratory measurements of value?
Authors: Marsh Aleksandra , Rovelli Grazia , Song Young-Chul , Pereira Kelly L. , Willoughby Rose E. , Bzdek Bryan R. , Hamilton Jacqueline F. , Orr-Ewing Andrew J. , Topping David O. , Reid Jonathan P.
Published: January 2017

Laboratory studies can provide important insights into the processes that occur at the scale of individual particles in ambient aerosol. We examine the accuracies of measurements of core physicochemical properties of aerosols that can be made in single particle studies and explore the impact of these properties on the microscopic processes that occur in ambient aerosol. Presenting new measurements, we examine here the refinements in our understanding of aerosol hygroscopicity, surface tension, viscosity and optical properties that can be gained from detailed laboratory measurements for complex mixtures through to surrogates for secondary organic atmospheric aerosols.
Superoxide generation from nNOS splice variants and its potential involvement in redox signal regulation
Authors: Ihara Hideshi , Kitamura Atsushi , Kasamatsu Shingo , Ida Tomoaki , Kakihana Yuki , Tsutsuki Hiroyasu , Sawa Tomohiro , Watanabe Yasuo , Akaike Takaaki
Published: January 2017

We previously demonstrated different spacial expression profiles of the neuronal nitric oxide (NO) synthase (nNOS) splice variants nNOS-µ and nNOS-α in the brain; however, their exact functions are not fully understood. Here, we used electron paramagnetic resonance to compare the electron-uncoupling reactions of recombinant nNOS-µ and nNOS-α that generate reactive oxygen species (ROS), in this case superoxide. nNOS-µ generated 44% of the amount of superoxide that nNOS-α generated. We also evaluated the ROS production in HEK293 cells stably expressing nNOS-α and nNOS-µ by investigating these electron-uncoupling reactions as induced by calcium ionophore A23187. A23187 treatment induced greater ROS production in HEK293 cells expressing nNOS-α than those expressing nNOS-µ. Also, immunocytochemical analysis revealed that A23187-treated cells expressing nNOS-α produced more 8-nitroguanosine 3′,5′-cyclic monophosphate, a second messenger in NO/ROS redox signaling, than did the cells expressing nNOS-µ. Molecular evolutionary analysis revealed that the ratio of nonsynonymous sites to synonymous sites for the nNOS-µ-specific region was higher than that for the complete gene, indicating that this region has fewer functional constraints than does the complete gene. These observations shed light on the physiological relevance of the nNOS-µ variant and may improve understanding of nNOS-dependent NO/ROS redox signaling and its pathophysiological consequences in neuronal systems.
Unique substrate specificity of ornithine aminotransferase from Toxoplasma gondii
Authors: Astegno Alessandra , Maresi Elena , Bertoldi Mariarita , La Verde Valentina , Paiardini Alessandro , Dominici Paola
Published: January 2017

Toxoplasma gondii is a protozoan parasite of medical and veterinary relevance responsible for toxoplasmosis in humans. As an efficacious vaccine remains a challenge, chemotherapy is still the most effective way to combat the disease. In search of novel druggable targets, we performed a thorough characterization of the putative pyridoxal 5′-phosphate (PLP)-dependent enzyme ornithine aminotransferase from T. gondii ME49 (TgOAT). We overexpressed the protein in Escherichia coli and analysed its molecular and kinetic properties by UV-visible absorbance, fluorescence and CD spectroscopy, in addition to kinetic studies of both the steady state and pre-steady state. TgOAT is largely similar to OATs from other species regarding its general transamination mechanism and spectral properties of PLP; however, it does not show a specific ornithine aminotransferase activity like its human homologue, but exhibits both N-acetylornithine and γ-aminobutyric acid (GABA) transaminase activity in vitro, suggesting a role in both arginine and GABA metabolism in vivo. The presence of Val79 in the active site of TgOAT in place of Tyr, as in its human counterpart, provides the necessary room to accommodate N-acetylornithine and GABA, resembling the active site arrangement of GABA transaminases. Moreover, mutation of Val79 to Tyr results in a change of substrate preference between GABA, N-acetylornithine and L-ornithine, suggesting a key role of Val79 in defining substrate specificity. The findings that TgOAT possesses parasite-specific structural features as well as differing substrate specificity from its human homologue make it an attractive target for anti-toxoplasmosis inhibitor design that can be exploited for chemotherapeutic intervention.
Mechanism and catalytic strategy of the prokaryotic-specific GTP cyclohydrolase-IB
Authors: Paranagama Naduni , Bonnett Shilah A. , Alvarez Jonathan , Luthra Amit , Stec Boguslaw , Gustafson Andrew , Iwata-Reuyl Dirk , Swairjo Manal A.
Published: January 2017

Guanosine 5′-triphosphate (GTP) cyclohydrolase-I (GCYH-I) catalyzes the first step in folic acid biosynthesis in bacteria and plants, biopterin biosynthesis in mammals, and the biosynthesis of 7-deazaguanosine-modified tRNA nucleosides in bacteria and archaea. The type IB GCYH (GCYH-IB) is a prokaryotic-specific enzyme found in many pathogens. GCYH-IB is structurally distinct from the canonical type IA GCYH involved in biopterin biosynthesis in humans and animals, and thus is of interest as a potential antibacterial drug target. We report kinetic and inhibition data of Neisseria gonorrhoeae GCYH-IB and two high-resolution crystal structures of the enzyme; one in complex with the reaction intermediate analog and competitive inhibitor 8-oxoguanosine 5′-triphosphate (8-oxo-GTP), and one with a tris(hydroxymethyl)aminomethane molecule bound in the active site and mimicking another reaction intermediate. Comparison with the type IA enzyme bound to 8-oxo-GTP (guanosine 5′-triphosphate) reveals an inverted mode of binding of the inhibitor ribosyl moiety and, together with site-directed mutagenesis data, shows that the two enzymes utilize different strategies for catalysis. Notably, the inhibitor interacts with a conserved active-site Cys149, and this residue is S-nitrosylated in the structures. This is the first structural characterization of a biologically S-nitrosylated bacterial protein. Mutagenesis and biochemical analyses demonstrate that Cys149 is essential for the cyclohydrolase reaction, and S-nitrosylation maintains enzyme activity, suggesting a potential role of the S-nitrosothiol in catalysis.
Structure-based mutational studies of O-acetylserine sulfhydrylase reveal the reason for the loss of cysteine synthase complex formation in Brucella abortus
Authors: Dharavath Sudhaker , Raj Isha , Gourinath Samudrala
Published: January 2017

Cysteine biosynthesis takes place via a two-step pathway in bacteria, fungi, plants and protozoan parasites, but not in humans, and hence, the machinery of cysteine biosynthesis is an opportune target for therapeutics. The decameric cysteine synthase complex (CSC) is formed when the C-terminal tail of serine acetyltransferase (SAT) binds in the active site of O-acetylserine sulfydrylase (OASS), playing a role in the regulation of this pathway. Here, we show that OASS from Brucella abortus (BaOASS) does not interact with its cognate SAT C-terminal tail. Crystal structures of native BaOASS showed that residues Gln96 and Tyr125 occupy the active-site pocket and interfere with the entry of the SAT C-terminal tail. The BaOASS (Q96A–Y125A) mutant showed relatively strong binding (Kd = 32.4 μM) to BaSAT C-terminal peptides in comparison with native BaOASS. The mutant structure looks similar except that the active-site pocket has enough space to bind the SAT C-terminal end. Surface plasmon resonance results showed a relatively strong (7.3 μM Kd) interaction between BaSAT and the BaOASS (Q96A–Y125A), but no interaction with native BaOASS. Taken together, our observations suggest that the CSC does not form in B. abortus.
Discovery and characterisation of the automethylation properties of PRDM9
Authors: Koh-Stenta Xiaoying , Poulsen Anders , Li Rong , Wee John Liang Kuan , Kwek Perlyn Zekui , Chew Sin Yin , Peng Jianhe , Wu Liling , Guccione Ernesto , Joy Joma , Hill Jeffrey
Published: January 2017

We have previously characterised the histone lysine methyltransferase properties of PRDM9, a member of the PRDM family of putative transcriptional regulators. PRDM9 displays broad substrate recognition and methylates a range of histone substrates, including octamers, core histone proteins, and peptides. In the present study, we show that PRDM9 performs intramolecular automethylation on multiple lysine residues localised to a lysine-rich region on the post-SET (suppressor of variegation 3–9, enhancer of zeste and trithorax) domain. PRDM9 automethylation is abolished by a single active-site mutation, C321P, also known to disrupt interactions with S-adenosylmethionine. We have taken an initial step towards tool compound generation through rational design of a substrate-mimic, peptidic inhibitor of PRDM9 automethylation. The discovery of automethylation in PRDM9 adds a new dimension to our understanding of PRDM9 enzymology.
Different specificities of two aldehyde dehydrogenases from Saccharomyces cerevisiae var. boulardii
Authors: Datta Suprama , Annapure Uday S. , Timson David J.
Published: January 2017

Aldehyde dehydrogenases play crucial roles in the detoxification of exogenous and endogenous aldehydes by catalysing their oxidation to carboxylic acid counterparts. The present study reports characterization of two such isoenzymes from the yeast Saccharomyces cerevisiae var. boulardii (NCYC 3264), one mitochondrial (Ald4p) and one cytosolic (Ald6p). Both Ald4p and Ald6p were oligomeric in solution and demonstrated positive kinetic cooperativity towards aldehyde substrates. Wild-type Ald6p showed activity only with aliphatic aldehydes. Ald4p, on the contrary, showed activity with benzaldehyde along with a limited range of aliphatic aldehydes. Inspection of modelled structure of Ald6p revealed that a bulky amino acid residue (Met177, compared with the equivalent residue Leu196 in Ald4p) might cause steric hindrance of cyclic substrates. Therefore, we hypothesized that specificities of the two isoenzymes towards aldehyde substrates were partly driven by steric hindrance in the active site. A variant of wild-type Ald6p with the Met177 residue replaced by a valine was also characterized to address to the hypothesis. It showed an increased specificity range and a gain of activity towards cyclohexanecarboxaldehyde. It also demonstrated an increased thermal stability when compared with both the wild-types. These data suggest that steric bulk in the active site of yeast aldehyde dehydrogenases is partially responsible for controlling specificity.
Security analysis of cyber‐physical systems using norm
Authors: Shames Iman , Farokhi Farhad , Summers Tyler H.
Published: January 2017

In this study, the effect of attacks on networked systems is studied and a new security index to analyse the impact of such attacks using norms of attacks to target and monitoring outputs is proposed. In addition, optimisation problems for selecting inputs or outputs that point to attacks with maximum impact and least detectability are posed, and subsequently solved. To demonstrate the applicability of the analysis methods proposed in this study, the IEEE 9‐bus and 50‐generator 145‐bus systems are considered as test cases.
Adaptive regularised l2‐boosting on clustered sparse coefficients for single image super‐resolution
Authors: Han Yulan , Zhao Yongping , Yu Haifeng
Published: January 2017

In this study, the authors propose a novel approach for single image super‐resolution. Their method is based on the idea of learning a mapping function, which can reveal the intrinsic relationship between sparse coefficients of low‐resolution (LR) and high‐resolution (HR) image patch pairs with respect to their individual dictionaries. Adaptive regularised l2‐boosting algorithm is proposed to learn this type of mapping function. Specifically, to reduce time consumption, the authors cluster training patches into several clusters. Within each cluster, a pair of dictionaries for LR and HR image patches is jointly trained. Adaptive regularised l2‐boosting algorithm is then employed to obtain the function. Thus, in a reconstruction stage, for each given input LR image patch, the authors can effectively estimate its corresponding HR image patch. Their extensive experimental results demonstrated that the proposed method achieves a performance of similar quality performance to that of the top methods.
Integration of open source tools for studying large‐scale distribution networks
Authors: Valverde Gustavo , Arguello Andrés , González Róger , Quirós‐Tortós Jairo
Published: January 2017

The penetration of low carbon technologies (LCTs) is expected to increase in the near future given the attractive incentives from governments, the cost effectiveness of the technologies and the appearance of smart grid schemes. To understand the corresponding benefits and challenges associated with them, power utilities are expected to run more sophisticated studies supported by more accurate and detailed models of distribution network (DN) elements and the network itself. This study presents the development of two software plugins that allow the integration of a geographical information system platform with a distribution system simulator. These plugins are intended to provide power utilities free and open source tools to explore the benefits and impacts of newly adopted LCTs and to analyse smart grid opportunities in large‐scale DNs. The effectiveness of the plugins is illustrated considering a real DN with 13,323 customers in Costa Rica. Results demonstrate that the plugins can successfully support in the creation of detailed network models and studies.
Regularised differentiation for image derivatives
Authors: Mathlouthi Yosra , Mitiche Amar , Ben Ayed Ismail
Published: January 2017

This study investigates a regularised differentiation method to estimate image derivatives. The scheme minimises an integral functional containing an anti‐differentiation data discrepancy term and a smoothness regularisation term. When discretised, the Euler–Lagrange necessary conditions for a minimum of the functional yield a large scale sparse system of linear equations, which can be solved efficiently by Jacobi/Gauss–Seidel iterations. The authors investigate the impact of the method in the context of two important problems in computer vision: optical flow and scene flow estimation. Quantitative results, using the Middlebury dataset and other real and synthetic images, show that the authors’ regularised differentiation scheme outperforms standard derivative definitions by smoothed finite differences, which are commonly used in motion analysis. The method can be readily used in various other image analysis problems.
System for load levelling control and operation of an energy storage system
Authors: Choe Jung‐Muk , Choe Gyu‐Ha , Lai Jih‐Sheng
Published: January 2017

In this study, the authors propose a feedback control method for energy storage systems for storing electrical energy and for load levelling. The proposed method uses both source and load power feedback, resulting in a fast response with respect to load levelling. To verify the proposed system, a power conditioning system based on the proposed feedback scheme was implemented and tested, in order to show the effectiveness of the scheme with respect to load levelling and energy harvesting. The system involved 60 of 50 W photovoltaic panels and a 20 Ah lithium polymer battery. An office was selected for testing, which was performed over an entire year. The authors obtained the operating profiles and determined the reduction in the daily total energy usage of the consumer as well as the standard deviation in load levelling.
Optimal control of piecewise deterministic Markov processes: a BSDE representation of the value function
Authors: Bandini Elena
Published: January 2017

We consider an infinite-horizon discounted optimal control problem for piecewise deterministic Markov processes, where a piecewise open-loop control acts continuously on the jump dynamics and on the deterministic flow. For this class of control problems, the value function can in general be characterized as the unique viscosity solution to the corresponding Hamilton−Jacobi−Bellman equation. We prove that the value function can be represented by means of a backward stochastic differential equation (BSDE) on infinite horizon, driven by a random measure and with a sign constraint on its martingale part, for which we give existence and uniqueness results. This probabilistic representation is known as nonlinear Feynman−Kac formula. Finally we show that the constrained BSDE is related to an auxiliary dominated control problem, whose value function coincides with the value function of the original non-dominated control problem.
New Insights in the Pathophysiology of Antiphospholipid Syndrome
Authors: Sacharidou Anastasia , Shaul Philip , Mineo Chieko
Published: January 2017

The antiphospholipid syndrome (APS) is an autoimmune disorder characterized by an elevated risk for arterial and venous thrombosis and pregnancy-related morbidity. Since the discovery of the disease in 1980s, numerous studies in cell culture systems, in animal models, and in patient populations have been reported, leading to a deeper understanding of the pathogenesis of APS. These studies have determined that circulating autoantibodies, collectively called antiphospholipid antibodies (aPL), the majority of which recognize cell surface proteins attached to the plasma membrane phospholipids, play a causal role in the development of the disease. The binding of aPL to the cell surface antigens triggers interaction of the complex with transmembrane receptors to initiate intracellular signaling in critical cell types, including platelets, monocytes, endothelial cells, and trophoblasts. Subsequent alteration of various cell functions results in inflammation, thrombus formation, and pregnancy complications. Apolipoprotein E receptor 2 (apoER2), a lipoprotein receptor family member, has been implicated as a mediator for aPL actions in platelets and endothelial cells. Nitric oxide (NO) is a signaling molecule known to exert potent antithrombotic, anti-inflammatory, and anti-atherogenic effects. NO insufficiency and oxidative stress have been linked to APS pathogenesis. This review will focus on the recent findings on how apoER2 and dysregulation of NO production contribute to aPL-mediated pathologies in APS.
Fast temperature relaxation model in dense plasmas
Authors: Faussurier Gérald , Blancard Christophe
Published: January 2017

We present a fast model to calculate the temperature-relaxation rates in dense plasmas. The electron-ion interaction-potential is calculated by combining a Yukawa approach and a finite-temperature Thomas-Fermi model. We include the internal energy as well as the excess energy of ions using the QEOS model. Comparisons with molecular dynamics simulations and calculations based on an average-atom model are presented. This approach allows the study of the temperature relaxation in a two-temperature electron-ion system in warm and hot dense matter.
Exciton dynamics in solid-state green fluorescent protein
Authors: Dietrich Christof P. , Siegert Marie , Betzold Simon , Ohmer Jürgen , Fischer Utz , Höfling Sven
Published: January 2017

We study the decay characteristics of Frenkel excitons in solid-state enhanced green fluorescent protein (eGFP) dried from solution. We further monitor the changes of the radiative exciton decay over time by crossing the phase transition from the solved to the solid state. Complex interactions between protonated and deprotonated states in solid-state eGFP can be identified from temperature-dependent and time-resolved fluorescence experiments that further allow the determination of activation energies for each identified process.
Non-invasive Hall current distribution measurement in a Hall effect thruster
Authors: Mullins Carl R. , Farnell Casey C. , Farnell Cody C. , Martinez Rafael A. , Liu David , Branam Richard D. , Williams John D.
Published: January 2017

A means is presented to determine the Hall current density distribution in a closed drift thruster by remotely measuring the magnetic field and solving the inverse problem for the current density. The magnetic field was measured by employing an array of eight tunneling magnetoresistive (TMR) sensors capable of milligauss sensitivity when placed in a high background field. The array was positioned just outside the thruster channel on a 1.5 kW Hall thruster equipped with a center-mounted hollow cathode. In the sensor array location, the static magnetic field is approximately 30 G, which is within the linear operating range of the TMR sensors. Furthermore, the induced field at this distance is approximately tens of milligauss, which is within the sensitivity range of the TMR sensors. Because of the nature of the inverse problem, the induced-field measurements do not provide the Hall current density by a simple inversion; however, a Tikhonov regularization of the induced field does provide the current density distributions. These distributions are shown as a function of time in contour plots. The measured ratios between the average Hall current and the average discharge current ranged from 6.1 to 7.3 over a range of operating conditions from 1.3 kW to 2.2 kW. The temporal inverse solution at 1.5 kW exhibited a breathing mode frequency of 24 kHz, which was in agreement with temporal measurements of the discharge current.
iRadMat: A thermo-mechanical testing system for in situ high-energy X-ray characterization of radioactive specimens
Authors: Zhang Xuan , Xu Chi , Wang Leyun , Chen Yiren , Li Meimei , Almer Jonathan D. , Benda Erika , Kenesei Peter , Mashayekhi Ali , Park Jun-Sang , Westferro Frank J.
Published: January 2017

We present an in situ Radiated Materials (iRadMat) experimental module designed to interface with a servo-hydraulic load frame for X-ray measurements at beamline 1-ID at the Advanced Photon Source. This new capability allows in situ studies of radioactive specimens subject to thermo-mechanical loading using a suite of high-energy X-ray scattering and imaging techniques. The iRadMat is a radiation-shielded vacuum heating system with the sample rotation-under-load capability. We describe the design features and performances of the iRadMat and present a dataset from a 300 °C uniaxial tensile test of a neutron-irradiated pure Fe specimen to demonstrate its capabilities.
Liquid bridge as a tunable-focus cylindrical liquid lens
Authors: Chen H. , Tabatabaei N. , Amirfazli A.
Published: January 2017

We proposed a method to create a tunable-focus cylindrical liquid lens using a liquid bridge between two narrow surfaces. Due to the surface edge effect, the interface of the liquid bridge (on the long side) was shown to be able to serve as a tunable-focus cylindrical liquid lens. The working distance of the lens can be adjusted by changing either or both of the height of the bridge (H) and the volume of the liquid (V). By varying H and V, the lens can serve as either diverging or converging lens, with a minimum working distance of 2.11 mm.
Modular soft x-ray spectrometer for applications in energy sciences and quantum materials
Authors: Chuang Yi-De , Shao Yu-Cheng , Cruz Alejandro , Hanzel Kelly , Brown Adam , Frano Alex , Qiao Ruimin , Smith Brian , Domning Edward , Huang Shih-Wen , Wray L. Andrew , Lee Wei-Sheng , Shen Zhi-Xun , Devereaux Thomas P. , Chiou Jaw-Wern , Pong Way-Faung , Yashchuk Valeriy V. , Gullikson Eric , Reininger Ruben , Yang Wanli , Guo Jinghua , Duarte Robert , Hussain Zahid
Published: January 2017

Over the past decade, the advances in grating-based soft X-ray spectrometers have revolutionized the soft X-ray spectroscopies in materials research. However, these novel spectrometers are mostly dedicated designs, which cannot be easily adopted for applications with diverging demands. Here we present a versatile spectrometer design concept based on the Hettrick-Underwood optical scheme that uses modular mechanical components. The spectrometer’s optics chamber can be used with gratings operated in either inside or outside orders, and the detector assembly can be reconfigured accordingly. The spectrometer can be designed to have high spectral resolution, exceeding 10 000 resolving power when using small source (∼1μm) and detector pixels (∼5μm) with high line density gratings (∼3000 lines/mm), or high throughput at moderate resolution. We report two such spectrometers with slightly different design goals and optical parameters in this paper. We show that the spectrometer with high throughput and large energy window is particularly useful for studying the sustainable energy materials. We demonstrate that the extensive resonant inelastic X-ray scattering (RIXS) map of battery cathode material LiNi1/3Co1/3Mn1/3O2 can be produced in few hours using such a spectrometer. Unlike analyzing only a handful of RIXS spectra taken at selected excitation photon energies across the elemental absorption edges to determine various spectral features like the localized dd excitations and non-resonant fluorescence emissions, these features can be easily identified in the RIXS maps. Studying such RIXS maps could reveal novel transition metal redox in battery compounds that are sometimes hard to be unambiguously identified in X-ray absorption and emission spectra. We propose that this modular spectrometer design can serve as the platform for further customization to meet specific scientific demands.
The coupled cluster method and entanglement in three fermion systems
Authors: Lévay Péter , Nagy Szilvia , Pipek János , Sárosi Gábor
Published: January 2017

The Coupled Cluster (CC) and full CI expansions are studied for three fermions with six and seven modes. Surprisingly the CC expansion is tailor made to characterize the usual stochastic local operations and classical communication (SLOCC) entanglement classes. It means that the notion of a SLOCC transformation shows up quite naturally as a one relating the CC and CI expansions, and going from the CI expansion to the CC one is equivalent to obtaining a form for the state where the structure of the entanglement classes is transparent. In this picture, entanglement is characterized by the parameters of the cluster operators describing transitions from occupied states to singles, doubles, and triples of non-occupied ones. Using the CC parametrization of states in the seven-mode case, we give a simple formula for the unique SLOCC invariant J. Then we consider a perturbation problem featuring a state from the unique SLOCC class characterized by J≠0. For this state with entanglement generated by doubles, we investigate the phenomenon of changing the entanglement type due to the perturbing effect of triples. We show that there are states with real amplitudes such that their entanglement encoded into configurations of clusters of doubles is protected from errors generated by triples. Finally we put forward a proposal to use the parameters of the cluster operator describing transitions to doubles for entanglement characterization. Compared to the usual SLOCC classes, this provides a coarse grained approach to fermionic entanglement.
A new model of organic solar cells reveals open circuit conditions and size dependent power loss induced by the finite conductivity of a transparent contact
Authors: Gotleyb Dor , Shikler Rafi
Published: January 2017

We report on a new approach to modelling the effect of the size of organic solar cells on their efficiency. Experimental results show a drastic deterioration in performance when scaling up organic solar cells. This reduction reflects in key parameters such as the short circuit current (Isc), the maximum power point (Pm), and the Fill Factor (FF). It is attributed to the transparent anode that exhibits a relatively low conductivity (σ). Our unique approach is to account for the interplay between the two sub-domains of the solar cell. In the first domain, containing the electro-optic active materials, we solve the drift-diffusion model using a simplified model for the recombination to emphasize the role of the anode resistance. In the second domain, representing the anode, we solve only the Laplace equation. We introduce the coupling between these layers using the current of the active layer as the boundary condition for the anode and the position dependent potential of the anode as the boundary condition for the active layer. Our results reveal that as the length of the cell increases, the parts that are farther from the contact exhibit near open circuit conditions and do not contribute to the current. We found that the efficiency of the cell altered from linear to sub-linear behavior already at cell lengths of a few millimeters. The transition point strongly depends on the conductivity of the anode. The sub-linearity starts at 0.4, 0.5, and 0.7 cm for σ=100, 200, and 500 S/cm, respectively. Additionally, the efficiency begins to saturate sooner than both the short circuit current and the Fill-Factor. The saturation is observed at device lengths of 0.8, 1.2, and 2.1 cm for σ=100, 200, and 500 S/cm, respectively.
Communication: Re-entrant limits of stability of the liquid phase and the Speedy scenario in colloidal model systems
Authors: Rovigatti Lorenzo , Bianco Valentino , Tavares José Maria , Sciortino Francesco
Published: January 2017

A re-entrant gas-liquid spinodal was proposed as a possible explanation of the apparent divergence of the compressibility and specific heat off supercooling water. Such a counter-intuitive possibility, e.g., a liquid that becomes unstable to gas-like fluctuations on cooling at positive pressure, has never been observed, neither in real substances nor in off-lattice simulations. More recently, such a re-entrant scenario has been dismissed on the premise that the re-entrant spinodal would collide with the gas-liquid coexisting curve (binodal) in the pressure-temperature plane. Here we study, numerically and analytically, two previously introduced one-component patchy particle models that both show (i) a re-entrant limit of stability of the liquid phase and (ii) a re-entrant binodal, providing a neat in silico (and in charta) realization of such unconventional thermodynamic scenario.
Threshold response using modulated continuous wave illumination for multilayer 3D optical data storage
Authors: Saini A. , Christenson C. W. , Khattab T. A. , Wang R. , Twieg R. J. , Singer K. D.
Published: January 2017

In order to achieve a high capacity 3D optical data storage medium, a nonlinear or threshold writing process is necessary to localize data in the axial dimension. To this end, commercial multilayer discs use thermal ablation of metal films or phase change materials to realize such a threshold process. This paper addresses a threshold writing mechanism relevant to recently reported fluorescence-based data storage in dye-doped co-extruded multilayer films. To gain understanding of the essential physics, single layer spun coat films were used so that the data is easily accessible by analytical techniques. Data were written by attenuating the fluorescence using nanosecond-range exposure times from a 488 nm continuous wave laser overlapping with the single photon absorption spectrum. The threshold writing process was studied over a range of exposure times and intensities, and with different fluorescent dyes. It was found that all of the dyes have a common temperature threshold where fluorescence begins to attenuate, and the physical nature of the thermal process was investigated.
Deep-level defects related to the emissive pits in thick InGaN films on GaN template and bulk substrates
Authors: Sumiya Masatomo , Toyomitsu Naoki , Nakano Yoshitaka , Wang Jianyu , Harada Yoshitomo , Sang Liwen , Sekiguchi Takashi , Yamaguchi Tomohiro , Honda Tohru
Published: January 2017

We studied the emissive pits in InGaN films grown on compressive and strain-free GaN underlying layers. Pit density decreased with the full width at half maximum of ω(0002) of InGaN. The films grew on compressive and strain-free GaN underlying layers with spiral and step-flow modes, respectively. Carbon impurities accumulated inside the pits. Comparison of cathodoluminescence inside the pits and steady-state photocapacitance spectra showed that the energy level of the carbon impurities appeared at ∼2.8 eV below the conduction band (Ec) for both types of pits. Deep-level defects at Ec −2.4 eV resulting in green fluorescence emission were considered to originate from pits related to screw dislocations.
Linear and nonlinear magneto-optical properties of monolayer phosphorene
Authors: Nguyen Chuong V. , Ngoc Hieu Nguyen , Duque C. A. , Quoc Khoa Doan , Van Hieu Nguyen , Van Tung Luong , Vinh Phuc Huynh
Published: January 2017

We theoretically study the magneto-optical properties of monolayer phosphorene under a perpendicular magnetic field. We evaluate linear, third-order nonlinear, and total absorption coefficients and relative refractive index changes as functions of the photon energy and the magnetic field, and show that they are strongly influenced by the magnetic field. The magneto-optical absorption coefficients and relative refractive index changes appear in two different regimes: the microwave to THz and the visible frequency. The amplitude of intra-band transition peaks is larger than that of the inter-band transitions. The resonant peaks are blue-shifted with the magnetic field. Our results demonstrate the potential of monolayer phosphorene as a new two-dimensional material for applications in nano-electronic and optical devices as a promising alternative to graphene.
Economies of scale: The physics basis
Authors: Bejan A. , Almerbati A. , Lorente S.
Published: January 2017

Why is size so important? Why are “economies of scale” a universal feature of all flow systems, animate, inanimate, and human made? The empirical evidence is clear: the bigger are more efficient carriers (per unit) than the smaller. This natural tendency is observed across the board, from animal design to technology, logistics, and economics. In this paper, we rely on physics (thermodynamics) to determine the relation between the efficiency and size. Here, the objective is to predict a natural phenomenon, which is universal. It is not to model a particular type of device. The objective is to demonstrate based on physics that the efficiencies of diverse power plants should increase with size. The analysis is performed in two ways. First is the tradeoff between the “external” irreversibilities due to the temperature differences that exist above and below the temperature range occupied by the circuit executed by the working fluid. Second is the allocation of the fluid flow irreversibility between the hot and cold portions of the fluid flow circuit. The implications of this report in economics and design science (scaling up, scaling down) and the necessity of multi-scale design with hierarchy are discussed.
Effect of nanopillar sublayer embedded with SiO2 on deep traps in green GaN/InGaN light emitting diodes
Authors: Lee In-Hwan , Cho Han-Su , Bae K. B. , Polyakov A. Y. , Smirnov N. B. , Zinovyev R. A. , Baek J. H. , Chung Tae-Hoon , Shchemerov I. V. , Kondratyev E. S. , Pearton S. J.
Published: January 2017

The effect of a layer of GaN nanopillars with SiO2 nanoparticles inserted into the n+-GaN contact Layer on the electrical properties, electroluminescence (EL) and photoluminescence (PL), admittance spectra, and deep trap spectra of green multi-quantum-well GaN/InGaN light emitting diodes (LEDs) grown by metalorganic chemical vapor deposition (MOCVD) on patterned sapphire substrates is reported. The PL and EL intensities for these SiO2 LEDs are measurably enhanced compared with reference to LEDs without the nanopillar sublayer. This correlates with the decrease in the SiO2 LEDs of the concentration of 0.25 eV electron traps and 0.45 eV hole traps, both located in the InGaN QWs.
Grating couplers in silicon-on-insulator: The role of photonic guided resonances on lineshape and bandwidth
Authors: Passoni M. , Gerace D. , Carroll L. , Andreani L. C.
Published: January 2017

Most grating couplers for silicon photonics are designed to match the approximately 10 μm mode-field diameter (MFD) of single-mode telecom fibres. In this letter, we analyse grating-coupler designs in the Silicon-on-Insulator (SOI) platform in a wide range of MFDs (4–100 μm) and related footprints, to give a physical understanding of the trends in efficiency and lineshape of the corresponding coupling spectra. We show that large-footprint grating couplers have an intrinsic Lorentzian lineshape that is determined by the quasi-guided photonic modes (or guided resonances) of the corresponding photonic crystal slab, while small-footprint grating couplers have a Gaussian lineshape resulting from the k-space broadening of the incident mode. The crossover between the two regimes is characterized by Voigt lineshapes. Multi-objective particle-swarm optimisation of selected small-footprint apodized grating-couplers is then used to locate the “Pareto fronts;” along which the highest coupling efficiency is achieved for a given bandwidth. This approach identifies several high-efficiency 220 nm SOI grating coupler designs with 1 dB bandwidths exceeding 100 nm. Such grating couplers are ideally suited for broadband photonic applications, such as wavelength-division multiplexing and environmental sensing, and are compatible with commercially available ultra-high numerical aperture fibres.