bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrafast Charge‐Transfer Reactions of Indoline Dyes with Anchoring Alkyl Chains of Varying Length in Mesoporous ZnO Solar Cells
Authors: Rohwer Egmont , Minda Iulia , Tauscher Gabriele , Richter Christoph , Miura Hidetoshi , Schlettwein Derck , Schwoerer Heinrich
Published: February 2015

Dye‐sensitized solar cells based on a mesoporous ZnO substrate were sensitized with the indoline derivatives DN91, DN216 and DN285. The chromophore is the same for each of these dyes. They differ from each other in the length of an alkyl chain, which provides a second anchor to the ZnO surface and prolongs cell lifetime. Ultrafast transient absorption measurements reveal a correlation between the length of the alkyl chain and the fastest electron‐injection process. The depopulation of the excited state and the associated emergence of the oxidized molecules are dominant spectral features in the transient absorption of the dyes with shorter alkyl chains. A slower picosecond‐scale decay proceeds at constant rate for all three derivatives and is assigned to electron transfer into the trap states of ZnO. All assignments are in good agreement with a higher quantum efficiency of charge injection leading to higher short‐circuit currents Jsc for dyes with shorter alkyl chains.
Dense or Porous Packing? Two‐Dimensional Self‐Assembly of Star‐Shaped Mono‐, Bi‐, and Terpyridine Derivatives
Authors: Trawny Daniel , Schlexer Philomena , Steenbergen Krista , Rabe Jürgen P. , Paulus Beate , Reissig Hans‐Ulrich
Published: February 2015

The self‐assembly behavior of five star‐shaped pyridyl‐functionalized 1,3,5‐triethynylbenzenes was studied at the interface between an organic solvent and the basal plane of graphite by scanning tunneling microscopy. The mono‐ and bipyridine derivatives self‐assemble in closely packed 2D crystals, whereas the derivative with the more bulky terpyridines crystallizes with porous packing. DFT calculations of a monopyridine derivative on graphene, support the proposed molecular model. The calculations also reveal the formation of hydrogen bonds between the nitrogen atoms and a hydrogen atom of the neighboring central unit, as a small nonzero tunneling current was calculated within this region. The title compounds provide a versatile model system to investigate the role of multivalent steric interactions and hydrogen bonding in molecular monolayers.
Robust sampled‐data control of uncertain switched neutral systems with probabilistic input delay
Authors: Selvi Subramaniam , Sakthivel Rathinasamy , Mathiyalagan Kalidass
Published: February 2015

This article focuses on the robust sampled‐data control for a class of uncertain switched neutral systems based on the average dwell‐time approach. In particular, the system is considered with probabilistic input delay using sampled state vectors, which are described by the stochastic variables with a Bernoulli distributed white sequence and time‐varying norm‐bounded uncertainties. By constructing a novel Lyapunov–Krasovskii functional which involves the lower and upper bounds of the delay, a new set of sufficient conditions are derived in terms of linear matrix inequalities for ensuring the robust exponential stability of the uncertain switched neutral system about its equilibrium point. Moreover, based on the stability criteria, a state feedback sampled‐data control law is designed for the considered system. Finally, a numerical example based on the water‐quality dynamic model for the Nile River is given to illustrate the effectiveness of the proposed design technique. © 2015 Wiley Periodicals, Inc. Complexity 21: 308–318, 2016
Activation of Ultrathin Films of Hematite for Photoelectrochemical Water Splitting via H2 Treatment
Authors: Moir Jonathon , Soheilnia Navid , Liao Kristine , O'Brien Paul , Tian Yao , Burch Kenneth S. , Ozin Geoffrey A.
Published: February 2015

Thermal treatment of ultrathin films of hematite (α‐Fe2O3) under an atmosphere of 5 % H2 in Ar is presented as a means of activating α‐Fe2O3 towards the photoelectrochemical splitting of water. Spin‐coated films annealed in air exhibited no photoactivity, whereas films treated in hydrogen exhibited a photocurrent response. X‐ray photoelectron spectroscopy and UV/Vis absorption spectroscopy results showed that the H2‐treated films contain oxygen vacancies, which suggests improved charge transport. However, Tafel slopes, scan‐rate dependent measurements, and kinetic analyses performed by using H2O2 as a hole scavenger suggested that surface modification may also contribute to their induced photoactivity. Electrochemical impedance spectroscopy results revealed the buildup of a surface trap capacitance at the point of photocurrent onset for the hydrogen‐treated films under illumination. A decrease in charge trapping resistance was also observed, which suggests improved transport of charges away from the surface.
Co‐Adsorbents: A Key Component in Efficient and Robust Dye‐Sensitized Solar Cells
Authors: Manthou Victoria S. , Pefkianakis Eleftherios K. , Falaras Polycarpos , Vougioukalakis Georgios C.
Published: February 2015

Since the establishment of dye‐sensitized solar cells in the early ‘90s, both the efficiency and stability of these third generation photovoltaics have been greatly enhanced. Nevertheless, there still exist many unwanted processes that impede operation of dye‐sensitized solar cells, encumbering the achievement of the maximum theoretical power conversion efficiency and decreasing the devices’ long‐term operation. These processes include charge recombination, dye aggregation, dye desorption, and high protonation degrees of the semiconductor’s surface. This Minireview focuses on a powerful strategy developed to address these problems, namely the use of co‐adsorbents. All types of co‐adsorbents utilized thus far are categorized in terms of the chemical identity of their anchoring group; in addition their operational mechanisms are presented and the properties that a functional molecule should possess to be applied as an efficient co‐adsorbent are discussed.
Hindsight regulates photoreceptor axon targeting through transcriptional control of jitterbug/Filamin and multiple genes involved in axon guidance in Drosophila
Authors: Oliva Carlos , Molina‐Fernandez Claudia , Maureira Miguel , Candia Noemi , López Estefanía , Hassan Bassem , Aerts Stein , Cánovas José , Olguín Patricio , Sierralta Jimena
Published: February 2015

During axon targeting, a stereotyped pattern of connectivity is achieved by the integration of intrinsic genetic programs and the response to extrinsic long and short‐range directional cues. How this coordination occurs is the subject of intense study. Transcription factors play a central role due to their ability to regulate the expression of multiple genes required to sense and respond to these cues during development. Here we show that the transcription factor HNT regulates layer‐specific photoreceptor axon targeting in Drosophila through transcriptional control of jbug/Filamin and multiple genes involved in axon guidance and cytoskeleton organization.Using a microarray analysis we identified 235 genes whose expression levels were changed by HNT overexpression in the eye primordia. We analyzed nine candidate genes involved in cytoskeleton regulation and axon guidance, six of which displayed significantly altered gene expression levels in hnt mutant retinas. Functional analysis confirmed the role of OTK/PTK7 in photoreceptor axon targeting and uncovered Tiggrin, an integrin ligand, and Jbug/Filamin, a conserved actin‐ binding protein, as new factors that participate of photoreceptor axon targeting. Moreover, we provided in silico and molecular evidence that supports jbug/Filamin as a direct transcriptional target of HNT and that HNT acts partially through Jbug/Filamin in vivo to regulate axon guidance. Our work broadens the understanding of how HNT regulates the coordinated expression of a group of genes to achieve the correct connectivity pattern in the Drosophila visual system. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 75: 1018–1032, 2015
A proteomic approach to understand MMP‐3‐driven developmental processes in the postnatal cerebellum: Chaperonin CCT6A and MAP kinase as contributing factors
Authors: Van Hove Inge , Verslegers Mieke , Hu Tjing‐Tjing , Carden Martin , Arckens Lutgarde , Moons Lieve
Published: February 2015

Matrix metalloproteinase‐3 (MMP‐3) deficiency in mice was previously reported to result in a transiently retarded granule cell migration at postnatal day 8 (P8) and a sustained disturbed arborization of Purkinje cell dendrites from P8 on, concomitant with a delayed synapse formation between granule cells and Purkinje cells and resulting in mild deficits in motor performance in adult animals. However, the molecular mechanisms by which MMP‐3 contributes to proper development of the cerebellar cortex during the first postnatal weeks remains unknown. In this study, we used a functional proteomics approach to investigate alterations in protein expression in postnatal cerebella of wild‐type versus MMP‐3 deficient mice, and to further elucidate MMP‐3‐dependent pathways and downstream targets in vivo. At P8, two‐dimensional difference gel electrophoresis and mass spectrometry identified 20 unique proteins with a different expression between the two genotypes. Subsequent “Ingenuity Pathway Analysis” and Western blotting indicate that the chaperonin containing T‐complex polypeptide 1, subunit 6A and the MAP kinase signaling pathway play a key role in the MMP‐3‐dependent regulation of neurite outgrowth and neuronal migration in the developing brain. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 75: 1033–1048, 2015
Calcium signaling in neocortical development
Authors: Uhlén Per , Fritz Nicolas , Smedler Erik , Malmersjö Seth , Kanatani Shigeaki
Published: February 2015

The calcium ion (Ca2+) is an essential second messenger that plays a pivotal role in neurogenesis. In the ventricular zone (VZ) of the neocortex, neural stem cells linger to produce progenitor cells and subsequently neurons and glial cells, which together build up the entire adult brain. The radial glial cells, with their characteristic radial fibers that stretch from the inner ventricular wall to the outer cortex, are known to be the neural stem cells of the neocortex. Migrating neurons use these radial fibers to climb from the proliferative VZ in the inner part of the brain to the outer layers of the cortex, where differentiation processes continue. To establish the complex structures that constitute the adult cerebral cortex, proliferation, migration, and differentiation must be tightly controlled by various signaling events, including cytosolic Ca2+ signaling. During development, cells regularly exhibit spontaneous Ca2+ activity that stimulates downstream effectors, which can elicit these fundamental cell processes. Spontaneous Ca2+ activity during early neocortical development depends heavily on gap junctions and voltage dependent Ca2+ channels, whereas later in development neurotransmitters and synapses exert an influence. Here, we provide an overview of the literature on Ca2+ signaling and its impact on cell proliferation, migration, and differentiation in the neocortex. We point out important historical studies and review recent progress in determining the role of Ca2+ signaling in neocortical development. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 75: 360–368, 2015
Linking riparian woody communities and fluviomorphological characteristics in a regulated gravel‐bed river (Piave River, Northern Italy)
Authors: Picco Lorenzo , Sitzia Tommaso , Mao Luca , Comiti Francesco , Lenzi Mario A.
Published: February 2015

Gravel‐bed rivers featuring a near dynamic equilibrium state usually display a good correspondence between geomorphological and riparian community gradients, whereas long‐term human alterations may disrupt these patterns. The aim of this study was to investigate the distribution of woody riparian vegetation on three geomorphic units – floodplains, bars, and islands along the Piave River, a gravel‐bed river located in Northern Italy suffering from various degrees of human pressure and disturbances. A total of 214 plots (4 × 4 m) along three cross sections in each of two sub‐reaches of the river were surveyed in order to identify the different morphological units, dendrological characteristics of standing plants, and species composition. Three riparian woody communities, with decreasing woody species richness and tree size, were identified by cluster analysis: Alnion incanae (n = 58), Salicion eleagni (n = 52), and Rhamno‐Prunetea (n = 27). The first was significantly associated with floodplains and the others with bars. No community showed a relatively stronger association with islands. Linear mixed models showed that the three geomorphic units significantly differed in mean elevation, fine sediment depth, and geomorphic persistence, but not all Tukey contrasts were significant, and absolute differences in mean elevation above talweg were quite small (<25 cm). Moreover, the three woody communities were not always related to corresponding geomorphological gradients, which reflected the river's complex history of channel adjustments. Most notably, mean grain size did not differ between either geomorphic or vegetation units. This study therefore indicates that riparian woody vegetation along altered gravel‐bed rivers may differ substantially from those characterizing near‐equilibrium river systems. Copyright © 2015 John Wiley & Sons, Ltd.
RASAL3, a novel hematopoietic RasGAP protein, regulates the number and functions of NKT cells
Authors: Saito Suguru , Kawamura Toshihiko , Higuchi Masaya , Kobayashi Takahiro , Yoshita‐Takahashi Manami , Yamazaki Maya , Abe Manabu , Sakimura Kenji , Kanda Yasuhiro , Kawamura Hiroki , Jiang Shuying , Naito Makoto , Yoshizaki Takumi , Takahashi Masahiko , Fujii Masahiro
Published: February 2015

Ras GTPase‐activating proteins negatively regulate the Ras/Erk signaling pathway, thereby playing crucial roles in the proliferation, function, and development of various types of cells. In this study, we identified a novel Ras GTPase‐activating proteins protein, RASAL3, which is predominantly expressed in cells of hematopoietic lineages, including NKT, B, and T cells. We established systemic RASAL3‐deficient mice, and the mice exhibited a severe decrease in NKT cells in the liver at 8 weeks of age. The treatment of RASAL3‐deficient mice with α‐GalCer, a specific agonist for NKT cells, induced liver damage, but the level was less severe than that in RASAL3‐competent mice, and the attenuated liver damage was accompanied by a reduced production of interleukin‐4 and interferon‐γ from NKT cells. RASAL3‐deficient NKT cells treated with α‐GalCer in vitro presented augmented Erk phosphorylation, suggesting that there is dysregulated Ras signaling in the NKT cells of RASAL3‐deficient mice. Taken together, these results suggest that RASAL3 plays an important role in the expansion and functions of NKT cells in the liver by negatively regulating Ras/Erk signaling, and might be a therapeutic target for NKT‐associated diseases.
Dendritic cell derived IL‐2 inhibits survival of terminally mature cells via an autocrine signaling pathway
Authors: Balachander Akhila , Nabti Sabrina , Sobota Radoslaw M. , Foo Shihui , Zolezzi Francesca , Lee Bernett T. K. , Poidinger Michael , Ricciardi‐Castagnoli Paola
Published: February 2015

DCs are crucial for sensing pathogens and triggering immune response. Upon activation by pathogen‐associated molecular pattern (PAMP) ligands, GM‐CSF myeloid DCs (GM‐DCs) secrete several cytokines, including IL‐2. DC IL‐2 has been shown to be important for innate and adaptive immune responses; however, IL‐2 importance in DC physiology has never been demonstrated. Here, we show that autocrine IL‐2 signaling is functional in murine GM‐DCs in an early time window after PAMPs stimulation. IL‐2 signaling selectively activates the JAK/STAT5 pathway by assembling holo‐receptor complexes at the cell surface. Using the sensitivity of targeted mass spectrometry, we show conclusively that GM‐DCs express CD122, the IL‐2 receptor β‐chain, at steady state. In myeloid DCs, this cytokine pathway inhibits survival of PAMP‐matured GM‐DCs which is crucial for maintaining immune tolerance and preventing autoimmunity. Our findings suggest that immune regulation by this novel autocrine signaling pathway can potentially be used in DC immunotherapy.
Whole genome amplification induced bias in the detection of KRAS‐mutated cell populations during colorectal carcinoma tissue testing
Authors: Stranska Jana , Jancik Sylwia , Slavkovsky Rastislav , Holinkova Veronika , Rabcanova Miroslava , Vojta Petr , Hajduch Marian , Drabek Jiri
Published: February 2015

Whole genome amplification replicates the entire DNA content of a sample and can thus help to circumvent material limitations when insufficient DNA is available for planned genetic analyses. However, there are conflicting data in the literature whether whole genome amplification introduces bias or reflects precisely the spectrum of starting DNA.

We analyzed the origins of discrepancies in KRAS (Kirsten rat sarcoma viral oncogene homolog gene) mutation detection in six of ten samples amplified using the GenomePlex® Tissue Whole Genome Amplification kit 5 (WGA5; Sigma‐Aldrich, St. Louis, MO, USA) and KRAS StripAssay® (KRAS SA; ViennaLab Diagnostics, Vienna, Austria).

We undertook reextraction, reamplification, retyping, authentication, reanalysis, and reinterpretation to determine whether the discrepancies originated during the preanalytical, analytical, and/or interpretative phase of genotyping.

We conclude that a combination of glass slide/sample heterogeneity and biased amplification due to stochastic effects in the early phases of whole genome amplification (WGA) may have adversely affected the results obtained. Our findings are relevant for both forensic genetics testing and massively parallel sequencing using preamplification.
Effects of bisphenol A on antioxidant system in soybean seedling roots
Authors: Wang Qingqing , Wang Lihong , Han Ruobing , Yang Linying , Zhou Qing , Huang Xiaohua
Published: February 2015

Bisphenol A (BPA), an emerging pollutant in the environment, has potential toxic effects on plants. The toxicity mechanism, however, remains largely unknown. The antioxidant system plays an important role in protecting plants against the damage of stress. The present study investigated the effects of BPA on the antioxidant system (superoxide dismutase [SOD], peroxidase [POD], catalase [CAT], ascorbic acid [AsA], proline, reduced glutathione [GSH]), reactive oxygen species (ROS; hydrogen peroxide [H2O2], superoxide anion [O2–]) accumulation, and membrane lipid peroxidation (malondialdehyde [MDA], cell membrane permeability) in soybean seedling roots. The 1.5 mg L−1 BPA exposure did not affect test indices in the roots. Exposure to 3.0 mg L−1, 6.0 mg L−1, 12.0 mg L−1, or 24.0 mg L−1 BPA caused increases in SOD (except for 3.0 mg L−1 BPA) and CAT activities, as well as in AsA, proline, and GSH (except for 3.0 mg L−1 BPA) content, leading to increases in the H2O2 and O2– content and to membrane lipid peroxidation. Exposure to 48.0 mg L−1 or 96.0 mg L−1 BPA caused decreases in the CAT activity and AsA/GSH content, as well as increases in the SOD and POD activities and the proline content, leading to excess ROS accumulation (i.e., H2O2 and O2–) and cell membrane damage. After withdrawal of BPA exposure, ROS accumulation and membrane lipid peroxidation were alleviated by regulating a special antioxidant enzyme or substance. Environ Toxicol Chem 2015;34:1127–1133. © 2015 SETAC
The developmental neurotoxicity of polybrominated diphenyl ethers: Effect of DE-71 on dopamine in zebrafish larvae
Authors: Wang Xianfeng , Yang Lihua , Wu Yuanyuan , Huang Changjiang , Wang Qiangwei , Han Jian , Guo Yongyong , Shi Xiongjie , Zhou Bingsheng
Published: February 2015

The potential neurotoxicity of polybrominated diphenyl ethers (PBDEs) is still a great concern. In the present study, the authors investigated whether exposure to PBDEs could affect the neurotransmitter system and cause developmental neurotoxicity in zebrafish. Zebrafish embryos (2 h postfertilization) were exposed to different concentrations of the PBDE mixture DE-71 (0–100 μg/L). The larvae were harvested at 120 h postfertilization, and the impact on dopaminergic signaling was investigated. The results revealed significant reductions in content of whole-body dopamine and its metabolite, dihydroxyphenylacetic acid, in DE-71–exposed larvae. The transcription of genes involved in the development of dopaminergic neurons (e.g., manf, bdnf, and nr4a2b) was significantly downregulated upon exposure to DE-71. Also, DE-71 resulted in a significant decrease of tyrosine hydroxylase and dopamine transporter protein levels in dopaminergic neurons. The expression level of tyrosine hydroxylase in forebrain neurons was assessed by whole-mount immunofluorescence, and the results further demonstrated that the tyrosine hydroxylase protein expression level was reduced in dopaminergic neurons. In addition to these molecular changes, the authors observed reduced locomotor activity in DE-71–exposed larvae. Taken together, the results of the present study demonstrate that acute exposure to PBDEs can affect dopaminergic signaling by disrupting the synthesis and transportation of dopamine in zebrafish, thereby disrupting normal neurodevelopment. In accord with its experimental findings, the present study extends knowledge of the mechanisms governing PBDE-induced developmental neurotoxicity. Environ Toxicol Chem 2015;34:1119–1126. © 2015 SETAC
Bone Engineering of Maxillary Sinus Bone Deficiencies Using Enriched CD90+ Stem Cell Therapy: A Randomized Clinical Trial
Authors: Kaigler Darnell , Avila-Ortiz Gustavo , Travan Suncica , Taut Andrei D , Padial-Molina Miguel , Rudek Ivan , Wang Feng , Lanis Alejandro , Giannobile William V
Published: February 2015

Bone engineering of localized craniofacial osseous defects or deficiencies by stem cell therapy offers strong prospects to improve treatment predictability for patient care. The aim of this phase 1/2 randomized, controlled clinical trial was to evaluate reconstruction of bone deficiencies of the maxillary sinus with transplantation of autologous cells enriched with CD90+ stem cells and CD14+ monocytes. Thirty human participants requiring bone augmentation of the maxillary sinus were enrolled. Patients presenting with 50% to 80% bone deficiencies of the maxillary sinus were randomized to receive either stem cells delivered onto a β-tricalcium phosphate scaffold or scaffold alone. Four months after treatment, clinical, radiographic, and histologic analyses were performed to evaluate de novo engineered bone. At the time of alveolar bone core harvest, oral implants were installed in the engineered bone and later functionally restored with dental tooth prostheses. Radiographic analyses showed no difference in the total bone volume gained between treatment groups; however, density of the engineered bone was higher in patients receiving stem cells. Bone core biopsies showed that stem cell therapy provided the greatest benefit in the most severe deficiencies, yielding better bone quality than control patients, as evidenced by higher bone volume fraction (BVF; 0.5 versus 0.4; p = 0.04). Assessment of the relation between degree of CD90+ stem cell enrichment and BVF showed that the higher the CD90 composition of transplanted cells, the greater the BVF of regenerated bone (r = 0.56; p = 0.05). Oral implants were placed and restored with functionally loaded dental restorations in all patients and no treatment-related adverse events were reported at the 1-year follow-up. These results provide evidence that cell-based therapy using enriched CD90+ stem cell populations is safe for maxillary sinus floor reconstruction and offers potential to accelerate and enhance tissue engineered bone quality in other craniofacial bone defects and deficiencies (Clinicaltrials.gov NCT00980278). © 2015 American Society for Bone and Mineral Research. © 2015 American Society for Bone and Mineral Research
MetREx: A protein design approach for the exploration of sequence‐reactivity relationships in metalloenzymes
Authors: Stiebritz Martin T.
Published: February 2015

Metalloenzymes represent a particular challenge for any rational (re)design approach because the modeling of reaction events at their metallic cofactors requires time‐consuming quantum mechanical calculations, which cannot easily be reconciled with the fast, knowledge‐based approaches commonly applied in protein design studies. Here, an approach for the exploration of sequence‐reactivity relationships in metalloenzymes is presented (MetREx) that consists of force field‐based screening of mutants that lie energetically between a wild‐type sequence and the global minimum energy conformation and which should, therefore, be compatible with a given protein fold. Mutant candidates are subsequently evaluated with a fast and approximate quantum mechanical/molecular mechanical‐like procedure that models the influence of the protein environment on the active site by taking partial charges and van der Waals repulsions into account. The feasibility of the procedure is demonstrated for the active site of [FeFe] hydrogenase from Desulfovibrio desulfuricans. The method described allows for the identification of mutants with altered properties, such as inhibitor‐coordination energies, and the understanding of the robustness of enzymatic reaction steps with respect to variations in sequence space. © 2015 Wiley Periodicals, Inc.
irGPU.proton.Net: Irregular strong charge interaction networks of protonatable groups in protein molecules—a GPU solver using the fast multipole method and statistical thermodynamics
Authors: Kantardjiev Alexander A.
Published: February 2015

Motivation: A cluster of strongly interacting ionization groups in protein molecules with irregular ionization behavior is suggestive for specific structure–function relationship. However, their computational treatment is unconventional (e.g., lack of convergence in naive self‐consistent iterative algorithm). The stringent evaluation requires evaluation of Boltzmann averaged statistical mechanics sums and electrostatic energy estimation for each microstate. Summary: irGPU: Irregular strong interactions in proteins—a GPU solver is novel solution to a versatile problem in protein biophysics—atypical protonation behavior of coupled groups. The computational severity of the problem is alleviated by parallelization (via GPU kernels) which is applied for the electrostatic interaction evaluation (including explicit electrostatics via the fast multipole method) as well as statistical mechanics sums (partition function) estimation. Special attention is given to the ease of the service and encapsulation of theoretical details without sacrificing rigor of computational procedures. irGPU is not just a solution‐in‐principle but a promising practical application with potential to entice community into deeper understanding of principles governing biomolecule mechanisms. © 2015 Wiley Periodicals, Inc.
Strategies for generating peptide radical cations via ion/ion reactions
Authors: Gilbert Joshua D. , Fisher Christine M. , Bu Jiexun , Prentice Boone M. , Redwine James G. , McLuckey Scott A.
Published: February 2015

Several approaches for the generation of peptide radical cations using ion/ion reactions coupled with either collision induced dissociation (CID) or ultraviolet photo dissociation (UVPD) are described here. Ion/ion reactions are used to generate electrostatic or covalent complexes comprised of a peptide and a radical reagent. The radical site of the reagent can be generated multiple ways. Reagents containing a carbon–iodine (C―I) bond are subjected to UVPD with 266‐nm photons, which selectively cleaves the C―I bond homolytically. Alternatively, reagents containing azo functionalities are collisionally activated to yield radical sites on either side of the azo group. Both of these methods generate an initial radical site on the reagent, which then abstracts a hydrogen from the peptide while the peptide and reagent are held together by either electrostatic interactions or a covalent linkage. These methods are demonstrated via ion/ion reactions between the model peptide RARARAA (doubly protonated) and various distonic anionic radical reagents. The radical site abstracts a hydrogen atom from the peptide, while the charge site abstracts a proton. The net result is the conversion of a doubly protonated peptide to a peptide radical cation. The peptide radical cations have been fragmented via CID and the resulting product ion mass spectra are compared to the control CID spectrum of the singly protonated, even‐electron species. This work is then extended to bradykinin, a more broadly studied peptide, for comparison with other radical peptide generation methods. The work presented here provides novel methods for generating peptide radical cations in the gas phase through ion/ion reaction complexes that do not require modification of the peptide in solution or generation of non‐covalent complexes in the electrospray process. Copyright © 2015 John Wiley & Sons, Ltd.
Modeling and comparative analysis of DC characteristics of AlGaN/GaN HEMT and MOSHEMT devices
Authors: Jena Kanjalochan , Swain Raghunandan , Lenka Trupti Ranjan
Published: February 2015

In this paper, a charge control model is developed for AlGaN/GaN High Electron Mobility Transistor (HEMT) and Metal Oxide Semiconductor High Electron Mobility Transistor (MOSHEMT) by considering the triangular potential well in the two‐dimensional electron gas (2DEG) and simulated with matlab. The obtained results from the developed model are compared with the experimental data for drain current, transconductance, gate capacitance and threshold voltage of both devices. The physics‐based models for 2DEG charge density, threshold voltage and gate capacitance have been developed. By using these developed models, the drain current for both linear and saturation modes is derived. The predicted threshold voltage with the variation of barrier thickness has been plotted. A positive threshold voltage can be obtained by decreasing the barrier thickness that builds up the foundation for enhancement mode MOSHEMTs. The predicted C‐V, Id‐Vgs, Id‐Vds and transconductance characteristics show an excellent agreement with the experimental results from the literature and hence validate the developed model. The results clearly establish the potential of using AlGaN/GaN MOSHEMT approach for high power microwave and switching applications. Copyright © 2015 John Wiley & Sons, Ltd.
Cochlear neuropathy in the rat exposed for a long period to moderate‐intensity noises
Authors: Gannouni Noura , Lenoir Marc , Ben Rhouma Khemais , El May Michèle , Tebourbi Olfa , Puel Jean Luc , Mhamdi Abada
Published: February 2015

Damaging effects on the cochlea of high‐intensity acoustic overexposures have been extensively documented, but only few works have focused on the danger of moderate noise levels. Using scanning and transmission electron microscopy, we explored the noise‐induced neuroepithelial changes that occur in the cochlea of rats subjected to moderate intensities, 70 and 85 dB SPL, for an extended period of time (6 hr/day over 3 months). Although the full quota of outer and inner sensory hair cells remained present, we detected discrete abnormalities, likely resulting from metabolic impairment, in both types of hair cell within the basal region of the cochlea. In contrast, important noise‐dependent losses of spiral ganglion neurons had occurred. In addition, we found cytoplasmic accumulations of lipofuscin‐like aggregates in most of the surviving cochlear neurons. These results strongly suggest that noise levels comparable to those of certain working environments, with sufficient exposure duration, pose a severe risk to the cochlea. Moreover, our data support the notion that long‐duration exposure to moderate noise is a causative factor of presbycusis. © 2015 Wiley Periodicals, Inc.
A Theoretical Study of the Kinetics of the Hydrogen Atom Abstraction Reactions from Cyclopropane by H, O (3P), and Cl (2P3/2) Atoms and OH Radicals
Authors: Louis Florent
Published: February 2015

The rate constants of the H‐abstraction reactions from cyclopropane by H, O (3P), Cl (2P3/2), and OH radicals have been calculated over the temperature range of 250−2500 K using two different levels of theory. Calculations of optimized geometrical parameters and vibrational frequencies are performed using the MP2 method combined with the cc‐pVTZ basis set and the 6–311++G(d,p) basis set. Single‐point energy calculations have been carried out with the highly correlated ab initio coupled cluster method in the space of single, double, and triple (perturbatively) electron excitations CCSD(T) using either the cc‐pVTZ, aug‐cc‐pVTZ, and aug‐cc‐pVQZ basis sets or the 6–311++G(3df,3pd) basis set. The CCSD(T) calculated potential energies have been extrapolated to the complete basis limit (CBS) limit. The Full Configuration Interaction (FCI) energies have been also estimated using the continued‐fraction approximation as proposed by Goodson (J. Chem. Phys., 2002, 116, 6948–6956). Canonical transition‐state theory combined with an Eckart tunneling correction has been used to predict the rate constants as a function of temperature using two kinetic models (direct abstraction or complex mechanism) at two levels of theory (CCSD(T)‐cf/CBS//MP2/cc‐pVTZ and CCSD(T)‐cf/6–311++G(3df,3pd)//MP2/6–311++G(d,p)). The calculated kinetic parameters are in reasonable agreement with their literature counterparts for all reactions. In the light of these trends, the use of the Pople‐style basis sets for studying the reactivity of other systems such as larger cycloalkanes or halogenated cycloalkanes is recommended because the 6–311++G(3df,3pd) basis set is less time consuming than the aug‐cc‐pVQZ basis set. Based on our calculations performed at the CCSD(T)‐cf/CBS//MP2/cc‐pVTZ level of theory, the standard enthalpy of formation at 298 K for the cyclopropyl radical has been reassessed and its value is (290.5 ± 1.6) kJ mol−1.
Health benefits of maternal supplementation with docosahexaenoic acid, folic acid, vitamin D and iodine during pregnancy and lactation for foetal and infant brain development and function
Authors: Morse Nancy
Published: February 2015

Dietary deficiencies of nutrients critical for foetal/infant brain development and function are increasingly being reported in scientific literature. Maternal supplementation with these nutrients within safe intake recommendations during pregnancy and while breast‐feeding has the potential to prevent many brain and central nervous system abnormalities and could enhance brain development and function in their children.
FDA MAUDE data on complications with lasers, light sources, and energy‐based devices
Authors: Tremaine Anne Marie , Avram Mathew M.
Published: February 2015

Background and Objective

It is essential for physicians to be fully informed regarding adverse events and malfunctions associated with medical devices that occur in routine practice. There is limited information on this important issue in the medical literature, and it is mostly based on initial studies and case reports. More advanced knowledge regarding device adverse events is necessary to guide physicians towards providing safe treatments. The FDA requires that manufacturers and device users submit medical device reports (MDRs) for suspected injuries from device use or malfunction. The database of MDRs, entitled Manufacturer and User Facility Device Experience (MAUDE) enables the FDA to monitor device performance and identify potential safety issues.

Study Design/Materials and Methods

We employed the following search strategy to identify reported adverse events. We searched the MAUDE electronic database on the FDA website in December 2013: http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/search.cfm We collected all reported cases between 1991 and December 2013. The search terms utilized included a comprehensive list of device manufacturers, specific product names, and the wavelengths/technology of the devices used in the field of dermatology.

Results

Our search yielded 1257 MDRs. Forty‐five MDRs were excluded due to insufficient data. The data is broken down into the adverse events observed, such as, but not limited to: blistering, burns, scarring, dyschromia, fat loss, and nerve palsy. The MDRs describe the adverse event and attempt to determine if it was related to device malfunction versus operator error. Radiofrequency devices, diode lasers, and intense pulsed light devices were the most commonly reported devices related to injuries.

Conclusion

1257 MDRs, from a myriad of devices used in dermatology, have been reported to the FDA as of December 2013. Despite the underreporting of adverse events, the MAUDE database is an untapped resource of post‐market surveillance of medical devices. The database can offer additional information, which combined with the initial device studies and published case reports from our colleagues, will help raise awareness and improve patient safety. Lasers Surg. Med. 47:133–140, 2015. © 2015 Wiley Periodicals, Inc.
RELN rare variants in myoclonus‐dystonia
Authors: Groen Justus L. , Ritz Katja , Jalalzadeh Hamid , van der Salm Sandra M.A. , Jongejan Aldo , Mook Olaf R. , Haagmans Martin A. , Zwinderman Aeilko H. , Motazacker Mahdi M. , Hennekam Raoul C. , Baas Frank , Tijssen Marina A.J.
Published: February 2015

Background

Myoclonus‐dystonia (M‐D) is a hyperkinetic movement disorder with predominant myoclonic symptoms combined with dystonia of the upper part of the body. A proportion of M‐D cases are caused by mutations in the epsilon‐sarcoglycan gene. In remaining M‐D patients, no genetic factor has been established, indicating genetic heterogeneity.

Methods

Patients were included in a prospective clinical database and recruited from referral centers and general neurology clinics in The Netherlands. To investigate new genetic causal factors in M‐D syndrome, we performed homozygosity mapping combined with exome sequencing in a three‐generation M‐D family and genetically screened 24 additional patients with M‐D.

Results

We found co‐segregation of the rare missense variant Thr1904Met in the RELN gene. By additional screening of an M‐D cohort, we identified co‐segregation of RELN variants in two families (Thr1904Met, Ile1217Met) and identified two sporadic RELN mutation carriers (Pro1703Arg, Leu411Ile). Taken together, five of 25 SGCE‐negative M‐D patients carried RELN rare missense variants.

Conclusion

We propose that RELN mutations contribute to the genetic heterogeneity of M‐D. Reelin is a large secreted glycoprotein that plays essential roles in the cytoarchitecture of laminated brain structures and modulation of synaptic transmission and plasticity. © 2015 International Parkinson and Movement Disorder Society
Incidence and prevalence of Parkinson's disease among Navajo people living in the Navajo nation
Authors: Gordon Paul H. , Mehal Jason M. , Holman Robert C. , Bartholomew Michael L. , Cheek James E. , Rowland Andrew S.
Published: February 2015

Parkinson's disease (PD) is largely unstudied among American Indians. Unique populations might harbor clues to elusive causes. We describe the incidence and prevalence of PD among Navajo people residing in the Navajo Nation, home to the largest American Indian tribe in the United States. We analyzed 2001‐2011 inpatient and outpatient visit data for Navajo people obtained from the Indian Health Service, which provides health care to American Indian people living on the Navajo Reservation. Cases were defined by at least two inpatient or outpatient visits with the diagnosis of PD. Crude and age‐adjusted incidence and prevalence rates were calculated overall as well as by age, sex, region of residence, and time period. Five hundred twenty‐four Navajo people with median age‐at‐onset of 74.0 years were diagnosed with PD during the study period, yielding an average annual crude incidence rate of 22.5/100,000. Age‐specific incidence was 232.0 for patients 65 years of age or older and 302.0 for 80 years of age or older. Age‐adjusted incidence was 35.9 overall (238.1 for ≥65 years), was higher in men than in women (47.5 vs. 27.7; P < 0.001), varied by region (P = 0.03), and was similar between time periods (2002‐2004 vs. 2009‐2011). The age‐adjusted point prevalence rate was 261.0. The rate of PD among Navajo People appears to be as high as or higher than rates reported in many other populations. Rates increased to the highest age group, consistent with population‐based studies. Further investigation is warranted to examine risk factors for PD in this remote population. © 2015 International Parkinson and Movement Disorder Society
Deep brain stimulation of the subthalamic nucleus: All that glitters isn't gold?
Authors: Galati Salvatore , Stefani Alessandro
Published: February 2015

With the silver anniversary of deep brain stimulation (DBS) behind us, this would seem to be a good juncture to consider its successes and unanswered questions. Bilateral subthalamic nucleus (STN) stimulation has changed the clinical perspective of several thousand Parkinson's disease (PD) patients worldwide. A recent reappraisal animates the field with strong arguments in favor of an anticipation of the stereotactic approach in patients with as little as 5 to 6 years of disease history if they manifest motor complications. From what was once a no‐choice option, STN‐DBS is now becoming more and more attractive to neurologists dealing with movement disorders. Despite the development of new pharmacological treatment and renewed rehabilitation programs able to modify the severity of drug‐related complications, a resurgence of stimulation therapy reminiscent of an old era of medicine with an attendant blinkered mindset has emerged. Yet, the DBS‐mediated effects are modest on critical aspects such as gait impairment and extremely variable depending on the clinical phenotype and individual clinical profile. Hence, the indication for DBS should become more, and not less, individually tailored. Those physicians considering deep brain stimulation (DBS) as a therapeutic option need to evaluate results beyond short‐term quality of life, giving the correct weight to the direct and indirect costs over the longer term as well as to life prognosis. Unequivocal recourse to early‐stimulation surgery necessitates investigations not limited to a mere comparative assessment versus drug‐mediated benefits, but instead showing evidence of a clear degree of disease‐modifying effect or a rescue of basal ganglia plasticity. © 2015 International Parkinson and Movement Disorder Society
Cognitive profile of LRRK2‐related Parkinson's disease
Authors: Srivatsal Sindhu , Cholerton Brenna , Leverenz James B. , Wszolek Zbigniew K. , Uitti Ryan J. , Dickson Dennis W. , Weintraub Daniel , Trojanowski John Q. , Van Deerlin Vivianna M. , Quinn Joseph F. , Chung Kathryn A. , Peterson Amie L. , Factor Stewart A. , Wood‐Siverio Cathy , Goldman Jennifer G. , Stebbins Glenn T. , Bernard Bryan , Ritz Beate , Rausch Rebecca , Espay Alberto J. , Revilla Fredy J. , Devoto Johnna , Rosenthal Liana S. , Dawson Ted M. , Albert Marilyn S. , Mata Ignacio F. , Hu Shu‐Ching , Montine Kathleen S. , Johnson Catherine , Montine Thomas J. , Edwards Karen L. , Zhang Jing , Zabetian Cyrus P.
Published: February 2015

Background

Increasing evidence suggests that genetic factors play a role in the variability associated with cognitive performance in Parkinson's disease (PD). Mutations in the LRRK2 gene are the most common cause of monogenic PD; however, the cognitive profile of LRRK2‐related PD is not well‐characterized.

Methods

A cohort of 1,447 PD patients enrolled in the PD Cognitive Genetics Consortium was screened for LRRK2 mutations and completed detailed cognitive testing. Associations between mutation carrier status and cognitive test scores were assessed using linear regression models.

Results

LRRK2 mutation carriers (n = 29) demonstrated better performance on the Mini Mental State Examination (P = 0.03) and the Letter‐Number Sequencing Test (P = 0.005). A smaller proportion of LRRK2 carriers were demented (P = 0.03).

Conclusions

Our cross‐sectional study demonstrates better performance on certain cognitive tests, as well as lower rates of dementia in LRRK2‐related PD. Future longitudinal studies are needed to determine whether LRRK2 mutation carriers exhibit slower cognitive decline. © 2015 International Parkinson and Movement Disorder Society
Homogeneous coordinates in motion correction
Authors: Zahneisen Benjamin , Ernst Thomas
Published: February 2015

Purpose

Prospective motion correction for MRI and other imaging modalities are commonly based on the assumption of affine motion, i.e., rotations, shearing, scaling and translations. In addition it often involves transformations between different reference frames, especially for applications with an external tracking device. The goal of this work is to develop a computational framework for motion correction based on homogeneous transforms.

Theory and Methods

The homogeneous representation of affine transformations uses 4 × 4 transformation matrices applied to four‐dimensional augmented vectors. It is demonstrated how homogenous transforms can be used to describe the motion of slice objects during an MRI scan. Furthermore, we extend the concept of homogeneous transforms to gradient and k‐space vectors, and show that the fourth dimension of an augmented k‐space vector encodes the complex phase of the corresponding signal sample due to translations.

Results

The validity of describing motion tracking in real space and k‐space using homogeneous transformations only is demonstrated on phantom experiments.

Conclusion

Homogeneous transformations allows for a conceptually simple, consistent and computationally efficient theoretical framework for motion correction applications. Magn Reson Med 75:274–279, 2016. © 2015 Wiley Periodicals, Inc.
Multi‐scale computational homogenization–localization for propagating discontinuities using X‐FEM
Authors: Bosco E. , Kouznetsova V. G. , Geers M. G. D.
Published: February 2015

The aim of this paper is to propose a continuous–discontinuous computational homogenization–localization framework to upscale microscale localization toward the onset and propagation of a cohesive discontinuity at the macroscale. The major novelty of this contribution is the development of a fully coupled micro–macro solution strategy, where the solution procedure for the macroscopic domain is based on the extended finite element method. The proposed approach departs from classical computational homogenization, which allows to derive the effective stress–strain response before the onset of localization. Upon strain localization, the microscale is characterized by a strain localization band where damage grows and by two adjacent unloading bulk regions at each side of the localization zone. The microscale localization band is lumped into a macroscopic cohesive crack, accommodated through discontinuity enriched macroscale kinematics. The governing response of the continuum with a discontinuity is obtained numerically based on proper scale transition relations in terms of the traction–separation law and the stress–strain description of the continuous surrounding material at both sides of the discontinuity. The potential of the method is demonstrated with a numerical example, which illustrates the onset and propagation of a macroscale cohesive crack emerging from microstructural damage within the underlying microstructure. Copyright © 2015 John Wiley & Sons, Ltd.