bluuebunny/crossref_metadata_2025 huggingface dataset:
Glow-to-arc transition events in H2-Ar direct current pulsed plasma: Automated measurement of current and voltage
Authors: Mendes Luciano A. , Mafra Márcio , Rodrigues Jhonatam C.
Published: January 2012

The glow-to-arc transition phenomena (arcing) observed in plasma reactors used in materials processing was studied through the arcs characteristic current and voltage waveforms. In order to capture these arcs signals, a LABVIEW™ based automated instrumentation system (ARCVIEW) was developed, including the integration of an oscilloscope equipped with proper current and voltage probes. The system also allows capturing the process parameters at the arc occurrence moments, which were used to map the arcs events conditions. Experiments in H2-Ar DC pulsed plasma returned signals data from 215 arcs events, which were analyzed through software routines. According to the results, an anti-arcing system should react in the time order of few microseconds to prevent most of the damage caused by the undesired arcing phenomena.
A comparison of light spot hydrophone and fiber optic probe hydrophone for lithotripter field characterization
Authors: Smith N. , Sankin G. N. , Simmons W. N. , Nanke R. , Fehre J. , Zhong P.
Published: January 2012

The performance of a newly developed light spot hydrophone (LSHD) in lithotripter field characterization was compared to that of the fiber optic probe hydrophone (FOPH). Pressure waveforms produced by a stable electromagnetic shock wave source were measured by the LSHD and FOPH under identical experimental conditions. In the low energy regime, focus and field acoustic parameters matched well between the two hydrophones. At clinically relevant high energy settings for shock wave lithotripsy, the measured leading compressive pressure waveforms matched closely with each other. However, the LSHD recorded slightly larger |P–| (p < 0.05) and secondary peak compressive pressures (p < 0.01) than the FOPH, leading to about 20% increase in total acoustic pulse energy calculated in a 6 mm radius around the focus (p = 0.06). Tensile pulse durations deviated ∼5% (p < 0.01) due to tensile wave shortening from cavitation activity using the LSHD. Intermittent compression spikes and laser light reflection artifacts have been correlated to bubble activity based on simultaneous high-speed imaging analysis. Altogether, both hydrophones are adequate for lithotripter field characterization as specified by the international standard IEC 61846.
Cyclotron resonance and intersubband transitions in symmetric InSb/AlInSb quantum wells with a perpendicular magnetic field
Authors: Wu X. G. , Zhang X. H.
Published: January 2012

Electronic states in symmetric InSb/AlInSb quantum wells are studied theoretically. An eight-band k·p calculation is performed for quantum wells with different barrier heights and well widths in the presence of a magnetic field applied perpendicularly to the quantum well. Influences due to strain and self-consistent Hartree potential are taken into account. By calculating transition energies and corresponding optical transition matrix elements, one can identify the calculated transitions as spin resolved cyclotron resonances, spin conserved, and spin flipped intersubband transitions. It is found that even with an in-plane optical polarization, the spin flipped intersubband transitions cannot be ignored completely. Using well-accepted bulk band parameters and experimentally known quantum well structure parameters, calculated transition energies are compared to experimental data of a recent magneto absorption measurement. A reasonably good agreement is found for the overall magnetic field dependence. The influence of a tilted magnetic field is also briefly discussed.
New view of the ICN A continuum using photoelectron spectroscopy of ICN−
Authors: Miller Elisa M. , Sheps Leonid , Lu Yu-Ju , Case Amanda S. , McCoy Anne B. , Carl Lineberger W.
Published: January 2012

Negative-ion photoelectron spectroscopy of ICN− (${\rm \tilde X}$X̃ 2Σ+) reveals transitions to the ground electronic state (${\rm \tilde X}$X̃ 1Σ+) of ICN as well as the first five excited states (3Π2, 3Π1, $\sideset{^3}{_{0^-}}{\Pi}$Π0−3, $\sideset{^3}{_{0^+}}{\Pi}$Π0+3, and 1Π1) that make up the ICN A continuum. By starting from the equilibrium geometry of the anion, photoelectron spectroscopy characterizes the electronic structure of ICN at an elongated I–C bond length of 2.65 Å. Because of this bond elongation, the lowest three excited states of ICN (3Π2, 3Π1, and $\sideset{^3}{_{0^-}}{\Pi}$Π0−3) are resolved for the first time in the photoelectron spectrum. In addition, the spectrum has a structured peak that arises from the frequently studied conical intersection between the $\sideset{^3}{_{0^+}}{\Pi}$Π0+3 and 1Π1 states. The assignment of the spectrum is aided by MR-SO-CISD calculations of the potential energy surfaces for the anion and neutral ICN electronic states, along with calculations of the vibrational levels supported by these states. Through thermochemical cycles involving spectrally narrow transitions to the excited states of ICN, we determine the electron affinity, EA(ICN), to be 1.345 (+0.04/−0.02) eV and the anion dissociation energy, D0(${\rm \tilde X}$X̃ 2Σ+ I–CN−), to be 0.83 (+0.04/−0.02) eV.
High-temperature annealing of thin Au films on Si: Growth of SiO2 nanowires or Au dendritic nanostructures?
Authors: Ruffino F. , Romano L. , Pitruzzello G. , Grimaldi M. G.
Published: January 2012

A simple and low-cost approach for the large-scale production of Au nanodendritic structures on Si is presented. Starting from the methodology involving deposition of a Au film on Si and heating the system to high temperatures in an inert ambient containing trace amounts of oxygen for the growth of SiO2 nanowires (NWs), we show that a suppression of the NWs growth and a promotion of the growth of Au nanodendrites occur when fast heating and cooling rates are used. We analyze the nanodendrites formation process considering the kinetics processes at the Au/Si interface in far from thermodynamic equilibrium situation.
Piezoelectric single crystal langatate and ferromagnetic composites: Studies on low-frequency and resonance magnetoelectric effects
Authors: Sreenivasulu G. , Fetisov L. Y. , Fetisov Y. K. , Srinivasan G.
Published: January 2012

Mechanical strain mediated magnetoelectric (ME) effects are studied in bilayers and trilayers of piezoelectric single-crystal lanthanum gallium tantalate (LGT) and magnetostrictive permendur (P). The ME voltage coefficient ranges from 2.3 V/cm Oe at 20 Hz to 720 V/cm Oe at bending resonance and is higher by an order of magnitude than in composites with ferroelectric lead zirconate titanate or lead magnesium niobate-lead titanate. The low-frequency magnetic noise for P-LGT-P is a factor of 2-10 smaller than for ferroelectrics based composites. Langatate is free of ferroelectric hysteresis, pyroelectric effects, and phase transitions up to 1450 °C and is of interest for ultrasensitive, high temperature magnetic sensors.
Magnetodielectric effects of Y3Fe5−xTixO12+x/2 ceramics
Authors: Wu Y. J. , Yu C. , Chen X. M. , Li J.
Published: January 2012

Dielectric, magnetic, and magnetodielectric properties of Y3Fe5−xTixO12+x/2 (x = 0, 0.1, 0.2) ceramics were investigated. Ti substitution induces a low temperature dielectric relaxation which comes from the charge carrier hopping between Ti3+ and Ti4+. The Maxwell-Wagner effect related dielectric relaxation becomes weak as the content of Ti increases. The extrinsic effect and intrinsic effect play a dominant role on the magnetodielectric effects for x = 0 at f < 500 kHz and f ≥ 500 kHz, respectively. The contribution of the extrinsic effects to magnetodielectric (MD) effect decreases and the contribution of the intrinsic effects to MD effect increases with increasing Ti amount.
Quantum Hall effect in bottom-gated epitaxial graphene grown on the C-face of SiC
Authors: Jouault B. , Camara N. , Jabakhanji B. , Caboni A. , Consejo C. , Godignon P. , Maude D. K. , Camassel J.
Published: January 2012

We demonstrate that the carrier concentration of epitaxial graphene devices grown on the C-face of a SiC substrate is efficiently modulated by a buried gate. The gate is fabricated via the implantation of nitrogen atoms in the SiC crystal. The charge neutrality point is observed close to gate voltage zero, and graphene can be populated by either holes or electrons down to low temperature (1.5 K). The hole concentration is hardly tuned by the gate voltage, possibly because of interface states below the Dirac point. A remarkably large quantum Hall plateau is observed for electrons.
Block type symmetry of bigraded Toda hierarchy
Authors: Li Chuanzhong , He Jingsong , Su Yucai
Published: January 2012

In this paper, we define Orlov-Schulman's operators ML, MR, and then use them to construct the additional symmetries of the bigraded Toda hierarchy. We further show that these additional symmetries form an interesting infinite-dimensional Lie algebra known as a Block type Lie algebra, whose structure theory and representation theory have recently received much attention in the literature. By acting on two different spaces under the weak W-constraints, we find in particular two representations of this Block type Lie algebra.
Mechanics of bacteriophage maturation
Authors: Roos Wouter H. , Gertsman Ilya , May Eric R. , Brooks Charles L. , Johnson John E. , Wuite Gijs J. L.
Published: January 2012

Capsid maturation with large-scale subunit reorganization occurs in virtually all viruses that use a motor to package nucleic acid into preformed particles. A variety of ensemble studies indicate that the particles gain greater stability during this process, however, it is unknown which material properties of the fragile procapsids change. Using Atomic Force Microscopy-based nano-indentation, we study the development of the mechanical properties during maturation of bacteriophage HK97, a
λ
-like phage of which the maturation-induced morphological changes are well described. We show that mechanical stabilization and strengthening occurs in three independent ways: (
i
) an increase of the Young’s modulus, (
ii
) a strong rise of the capsid’s ultimate strength, and (
iii
) a growth of the resistance against material fatigue. The Young’s modulus of immature and mature capsids, as determined from thin shell theory, fit with the values calculated using a new multiscale simulation approach. This multiscale calculation shows that the increase in Young’s modulus isn’t dependent on the crosslinking between capsomers.
In contrast
, the ultimate strength of the capsids does increase even when a limited number of cross-links are formed while full crosslinking appears to protect the shell against material fatigue. Compared to phage
λ
, the covalent crosslinking at the icosahedral and quasi threefold axes of HK97 yields a mechanically more robust particle than the addition of the gpD protein during maturation of phage
λ
. These results corroborate the expected increase in capsid stability and strength during maturation, however in an unexpected intricate way, underlining the complex structure of these self-assembling nanocontainers.
Origins of tumor-associated macrophages and neutrophils
Authors: Cortez-Retamozo Virna , Etzrodt Martin , Newton Andita , Rauch Philipp J. , Chudnovskiy Aleksey , Berger Cedric , Ryan Russell J. H. , Iwamoto Yoshiko , Marinelli Brett , Gorbatov Rostic , Forghani Reza , Novobrantseva Tatiana I. , Koteliansky Victor , Figueiredo Jose-Luiz , Chen John W. , Anderson Daniel G. , Nahrendorf Matthias , Swirski Filip K. , Weissleder Ralph , Pittet Mikael J.
Published: January 2012

Tumor-associated macrophages (TAMs) and tumor-associated neutrophils (TANs) can control cancer growth and exist in almost all solid neoplasms. The cells are known to descend from immature monocytic and granulocytic cells, respectively, which are produced in the bone marrow. However, the spleen is also a recently identified reservoir of monocytes, which can play a significant role in the inflammatory response that follows acute injury. Here, we evaluated the role of the splenic reservoir in a genetic mouse model of lung adenocarcinoma driven by activation of oncogenic Kras and inactivation of p53. We found that high numbers of TAM and TAN precursors physically relocated from the spleen to the tumor stroma, and that recruitment of tumor-promoting spleen-derived TAMs required signaling of the chemokine receptor CCR2. Also, removal of the spleen, either before or after tumor initiation, reduced TAM and TAN responses significantly and delayed tumor growth. The mechanism by which the spleen was able to maintain its reservoir capacity throughout tumor progression involved, in part, local accumulation in the splenic red pulp of typically rare extramedullary hematopoietic stem and progenitor cells, notably granulocyte and macrophage progenitors, which produced CD11b
+
Ly-6C
hi
monocytic and CD11b
+
Ly-6G
hi
granulocytic cells locally. Splenic granulocyte and macrophage progenitors and their descendants were likewise identified in clinical specimens. The present study sheds light on the origins of TAMs and TANs, and positions the spleen as an important extramedullary site, which can continuously supply growing tumors with these cells.
Horizontal transfer of chloroplast genomes between plant species
Authors: Stegemann Sandra , Keuthe Mandy , Greiner Stephan , Bock Ralph
Published: January 2012

The genomes of DNA-containing cell organelles (mitochondria, chloroplasts) can be laterally transmitted between organisms, a process known as organelle capture. Organelle capture often occurs in the absence of detectable nuclear introgression, and the capture mechanism is unknown. Here, we have considered horizontal genome transfer across natural grafts as a mechanism underlying chloroplast capture in plants. By grafting sexually incompatible species, we show that complete chloroplast genomes can travel across the graft junction from one species into another. We demonstrate that, consistent with reported phylogenetic evidence, replacement of the resident plastid genome by the alien genome occurs in the absence of intergenomic recombination. Our results provide a plausible mechanism for organelle capture in plants and suggest natural grafting as a path for horizontal gene and genome transfer between sexually incompatible species.
Synthetic model of the asymmetric [Mn
3
CaO
4
] cubane core of the oxygen-evolving complex of photosystem II
Authors: Mukherjee Shreya , Stull Jamie A. , Yano Junko , Stamatatos Theocharis C. , Pringouri Konstantina , Stich Troy A. , Abboud Khalil A. , Britt R. David , Yachandra Vittal K. , Christou George
Published: January 2012

The laboratory synthesis of the oxygen-evolving complex (OEC) of photosystem II has been the objective of synthetic chemists since the early 1970s. However, the absence of structural information on the OEC has hampered these efforts. Crystallographic reports on photosystem II that have been appearing at ever-improving resolution over the past ten years have finally provided invaluable structural information on the OEC and show that it comprises a [Mn
3
CaO
4
] distorted cubane, to which is attached a fourth, external Mn atom, and the whole unit attached to polypeptides primarily by aspartate and glutamate carboxylate groups. Such a heterometallic Mn/Ca cubane with an additional metal attached to it has been unknown in the literature. This paper reports the laboratory synthesis of such an asymmetric cubane-containing compound with a bound external metal atom, [

(
1
)] . All peripheral ligands are carboxylate or carboxylic acid groups. Variable-temperature magnetic susceptibility data have established
1
to possess an
S
 = 9/2 ground state. EPR spectroscopy confirms this, and the Davies electron nuclear double resonance data reveal similar hyperfine couplings to those of other Mn
IV
species, including the OEC S
2
state. Comparison of the X-ray absorption data with those for the OEC reveal
1
to possess structural parameters that make it a close structural model of the asymmetric-cubane OEC unit. This geometric and electronic structural correspondence opens up a new front in the multidisciplinary study of the properties and function of this important biological unit.
Rabenosyn-5 defines the fate of the transferrin receptor following clathrin-mediated endocytosis
Authors: Navaroli Deanna M. , Bellvé Karl D. , Standley Clive , Lifshitz Lawrence M. , Cardia James , Lambright David , Leonard Deborah , Fogarty Kevin E. , Corvera Silvia
Published: January 2012

Cell surface receptors and other proteins internalize through diverse mechanisms at the plasma membrane and are sorted to different destinations. Different subpopulations of early endosomes have been described, raising the question of whether different internalization mechanisms deliver cargo into different subsets of early endosomes. To address this fundamental question, we developed a microscopy platform to detect the precise position of endosomes relative to the plasma membrane during the uptake of ligands. Axial resolution is maximized by concurrently applied total internal reflection fluorescence and epifluorescence-structured light. We found that transferrin receptors are delivered selectively from clathrin-coated pits on the plasma membrane into a specific subpopulation of endosomes enriched in the multivalent Rab GTPase and phosphoinositide-binding protein Rabenosyn-5. Depletion of Rabenosyn-5, but not of other early endosomal proteins such as early endosome antigen 1, resulted in impaired transferrin uptake and lysosomal degradation of transferrin receptors. These studies reveal a critical role for Rabenosyn-5 in determining the fate of transferrin receptors internalized by clathrin-mediated endocytosis and, more broadly, a mechanism whereby the delivery of cargo from the plasma membrane into specific early endosome subpopulations is required for its appropriate intracellular traffic.
Stage-specific functions of leukemia/lymphoma-related factor (LRF) in the transcriptional control of osteoclast development
Authors: Tsuji-Takechi Kaori , Negishi-Koga Takako , Sumiya Eriko , Kukita Akiko , Kato Shigeaki , Maeda Takahiro , Pandolfi Pier Paolo , Moriyama Keiji , Takayanagi Hiroshi
Published: January 2012

Cell fate determination is tightly regulated by transcriptional activators and repressors. Leukemia/lymphoma-related factor (LRF; encoded by
Zbtb7a
), known as a POK (POZ/BTB and
Krüppel
) family transcriptional repressor, is induced during the development of bone-resorbing osteoclasts, but the physiological significance of LRF in bone metabolism and the molecular mechanisms underlying the transcriptional regulation of osteoclastogenesis by LRF have not been elucidated. Here we show that LRF negatively regulates osteoclast differentiation by repressing nuclear factor of activated T cells c1 (NFATc1) induction in the early phase of osteoclast development, while positively regulating osteoclast-specific genes by functioning as a coactivator of NFATc1 in the bone resorption phase. The stage-specific distinct functions of LRF were demonstrated in two lines of conditional knockout mice in which LRF was deleted in the early or late phase of osteoclast development. Thus, this study shows that LRF plays stage-specific distinct roles in osteoclast differentiation, exemplifying the delicate transcriptional regulation at work in lineage commitment.
Integrated cross-species transcriptional network analysis of metastatic susceptibility
Authors: Hu Ying , Wu Gang , Rusch Michael , Lukes Luanne , Buetow Kenneth H. , Zhang Jinghui , Hunter Kent W.
Published: January 2012

Metastatic disease is the proximal cause of mortality for most cancers and remains a significant problem for the clinical management of neoplastic disease. Recent advances in global transcriptional analysis have enabled better prediction of individuals likely to progress to metastatic disease. However, minimal overlap between predictive signatures has precluded easy identification of key biological processes contributing to the prometastatic transcriptional state. To overcome this limitation, we have applied network analysis to two independent human breast cancer datasets and three different mouse populations developed for quantitative analysis of metastasis. Analysis of these datasets revealed that the gene membership of the networks is highly conserved within and between species, and that these networks predicted distant metastasis free survival. Furthermore these results suggest that susceptibility to metastatic disease is cell-autonomous in estrogen receptor-positive tumors and associated with the mitotic spindle checkpoint. In contrast, nontumor genetics and pathway activities-associated stromal biology are significant modifiers of the rate of metastatic spread of estrogen receptor-negative tumors. These results suggest that the application of network analysis across species may provide a robust method to identify key biological programs associated with human cancer progression.
Detailing the optimality of photosynthesis in cyanobacteria through systems biology analysis
Authors: Nogales Juan , Gudmundsson Steinn , Knight Eric M. , Palsson Bernhard O. , Thiele Ines
Published: January 2012

Photosynthesis has recently gained considerable attention for its potential role in the development of renewable energy sources. Optimizing photosynthetic organisms for biomass or biofuel production will therefore require a systems understanding of photosynthetic processes. We reconstructed a high-quality genome-scale metabolic network for
Synechocystis
sp. PCC6803 that describes key photosynthetic processes in mechanistic detail. We performed an exhaustive in silico analysis of the reconstructed photosynthetic process under different light and inorganic carbon (
Ci
) conditions as well as under genetic perturbations. Our key results include the following. (
i
) We identified two main states of the photosynthetic apparatus: a
Ci
-limited state and a light-limited state. (
ii
) We discovered nine alternative electron flow pathways that assist the photosynthetic linear electron flow in optimizing the photosynthesis performance. (
iii
) A high degree of cooperativity between alternative pathways was found to be critical for optimal autotrophic metabolism. Although pathways with high photosynthetic yield exist for optimizing growth under suboptimal light conditions, pathways with low photosynthetic yield guarantee optimal growth under excessive light or
Ci
limitation. (
iv
) Photorespiration was found to be essential for the optimal photosynthetic process, clarifying its role in high-light acclimation. Finally, (
v
) an extremely high photosynthetic robustness drives the optimal autotrophic metabolism at the expense of metabolic versatility and robustness. The results and modeling approach presented here may promote a better understanding of the photosynthetic process. They can also guide bioengineering projects toward optimal biofuel production in photosynthetic organisms.
Exposure to anticancer drugs can result in transgenerational genomic instability in mice
Authors: Glen Colin D. , Dubrova Yuri E.
Published: January 2012

The genetic effects of human exposure to anticancer drugs remain poorly understood. To establish whether exposure to anticancer drugs can result not only in mutation induction in the germ line of treated animals, but also in altered mutation rates in their offspring, we evaluated mutation rates in the offspring of male mice treated with three commonly used chemotherapeutic agents: cyclophosphamide, mitomycin C, and procarbazine. The doses of paternal exposure were approximately equivalent to those used clinically. Using single-molecule PCR, the frequency of mutation at the mouse expanded simple tandem repeat locus
Ms6-hm
was established in DNA samples extracted from sperm and bone marrow of the offspring of treated males. After paternal exposure to any one of these three drugs, expanded simple tandem repeat mutation frequencies were significantly elevated in the germ line (sperm) and bone marrow of their offspring. This observed transgenerational instability was attributed to elevated mutation rates at the alleles derived from both the exposed fathers and from the nonexposed mothers, thus implying a genome-wide destabilization. Our results suggest that paternal exposure to a wide variety of mutagens can result in transgenerational instability manifesting in their offspring. Our data also raise important issues concerning delayed transgenerational effects in the children of survivors of anticancer therapy.
Inhibiting platelet-stimulated blood coagulation by inhibition of mitochondrial respiration
Authors: Barile Christopher J. , Herrmann Paul C. , Tyvoll David A. , Collman James P. , Decreau Richard A. , Bull Brian S.
Published: January 2012

Platelets are important mediators of blood coagulation that lack nuclei, but contain mitochondria. Although the presence of mitochondria in platelets has long been recognized, platelet mitochondrial function remains largely unaddressed. On the basis of a small amount of literature that suggests platelet mitochondria are functional, we hypothesized that the inhibition of platelet mitochondria disrupts platelet function and platelet-activated blood coagulation. To test this hypothesis, members of the tetrazole, thiazole, and 1,2,3-triazole families of small molecule heterocycles were screened for the ability to inhibit isolated mitochondrial respiration and coagulation of whole blood. The families of heterocycles screened were chosen on the basis of the ability of the heterocycle family to inhibit a biomimetic model of cytochrome
c
oxidase (CcO). The strength of mitochondrial inhibition correlates with each compound's ability to deter platelet stimulation and platelet-activated blood clotting. These results suggest that for this class of molecules, inhibition of blood coagulation may be occurring through a mechanism involving mitochondrial inhibition.
Nonimmunoglobulin target loci of activation-induced cytidine deaminase (AID) share unique features with immunoglobulin genes
Authors: Kato Lucia , Begum Nasim A. , Burroughs A. Maxwell , Doi Tomomitsu , Kawai Jun , Daub Carsten O. , Kawaguchi Takahisa , Matsuda Fumihiko , Hayashizaki Yoshihide , Honjo Tasuku
Published: January 2012

Activation-induced cytidine deaminase (AID) is required for both somatic hypermutation and class-switch recombination in activated B cells. AID is also known to target nonimmunoglobulin genes and introduce mutations or chromosomal translocations, eventually causing tumors. To identify as-yet-unknown AID targets, we screened early AID-induced DNA breaks by using two independent genome-wide approaches. Along with known AID targets, this screen identified a set of unique genes (
SNHG3, MALAT1, BCL7A,
and
CUX1
) and confirmed that these loci accumulated mutations as frequently as
Ig
locus after AID activation. Moreover, these genes share three important characteristics with the Ig gene: translocations in tumors, repetitive sequences, and the epigenetic modification of chromatin by H3K4 trimethylation in the vicinity of cleavage sites.
Robust chromosomal DNA repair via alternative end-joining in the absence of X-ray repair cross-complementing protein 1 (XRCC1)
Authors: Boboila Cristian , Oksenych Valentyn , Gostissa Monica , Wang Jing H. , Zha Shan , Zhang Yu , Chai Hua , Lee Cheng-Sheng , Jankovic Mila , Saez Liz-Marie Albertorio , Nussenzweig Michel C. , McKinnon Peter J. , Alt Frederick W. , Schwer Bjoern
Published: January 2012

Classical nonhomologous DNA end-joining (C-NHEJ), which is a major DNA double-strand break (DSB) repair pathway in mammalian cells, plays a dominant role in joining DSBs during Ig heavy chain (IgH) class switch recombination (CSR) in activated B lymphocytes. However, in B cells deficient for one or more requisite C-NHEJ factors, such as DNA ligase 4 (Lig4) or XRCC4, end-joining during CSR occurs by a distinct alternative end-joining (A-EJ) pathway. A-EJ also has been implicated in joining DSBs found in oncogenic chromosomal translocations. DNA ligase 3 (Lig3) and its cofactor XRCC1 are widely considered to be requisite A-EJ factors, based on biochemical studies or extrachromosomal substrate end-joining studies. However, potential roles for these factors in A-EJ of endogenous chromosomal DSBs have not been tested. Here, we report that
Xrcc1
inactivation via conditional gene-targeted deletion in WT or XRCC4-deficient primary B cells does not have an impact on either CSR or
IgH/c-myc
translocations in activated B lymphocytes. Indeed, homozygous deletion of
Xrcc1
does not impair A-EJ of I-SceI–induced DSBs in XRCC4-deficient pro–B-cell lines. Correspondingly, substantial depletion of Lig3 in Lig4-deficient primary B cells or B-cell lines does not impair A-EJ of CSR-mediated DSBs or formation of
IgH/c-myc
translocations. Our findings firmly demonstrate that XRCC1 is not a requisite factor for A-EJ of chromosomal DSBs and raise the possibility that DNA ligase 1 (Lig1) may contribute more to A-EJ than previously considered.
Reduced release probability prevents vesicle depletion and transmission failure at dynamin mutant synapses
Authors: Lou Xuelin , Fan Fan , Messa Mirko , Raimondi Andrea , Wu Yumei , Looger Loren L. , Ferguson Shawn M. , De Camilli Pietro
Published: January 2012

Endocytic recycling of synaptic vesicles after exocytosis is critical for nervous system function. At synapses of cultured neurons that lack the two “neuronal” dynamins, dynamin 1 and 3, smaller excitatory postsynaptic currents are observed due to an impairment of the fission reaction of endocytosis that results in an accumulation of arrested clathrin-coated pits and a greatly reduced synaptic vesicle number. Surprisingly, despite a smaller readily releasable vesicle pool and fewer docked vesicles, a strong facilitation, which correlated with lower vesicle release probability, was observed upon action potential stimulation at such synapses. Furthermore, although network activity in mutant cultures was lower, Ca
2+
/calmodulin-dependent protein kinase II (CaMKII) activity was unexpectedly increased, consistent with the previous report of an enhanced state of synapsin 1 phosphorylation at CaMKII-dependent sites in such neurons. These changes were partially reversed by overnight silencing of synaptic activity with tetrodotoxin, a treatment that allows progression of arrested endocytic pits to synaptic vesicles. Facilitation was also counteracted by CaMKII inhibition. These findings reveal a mechanism aimed at preventing synaptic transmission failure due to vesicle depletion when recycling vesicle traffic is backed up by a defect in dynamin-dependent endocytosis and provide new insight into the coupling between endocytosis and exocytosis.
Tcl1 protein functions as an inhibitor of de novo DNA methylation in B-cell chronic lymphocytic leukemia (CLL)
Authors: Palamarchuk Alexey , Yan Pearlly S. , Zanesi Nicola , Wang Linan , Rodrigues Benjamin , Murphy Mark , Balatti Veronica , Bottoni Arianna , Nazaryan Natalya , Alder Hansjuerg , Rassenti Laura , Kipps Thomas J. , Freitas Michael , Croce Carlo M. , Pekarsky Yuri
Published: January 2012

B-cell chronic lymphocytic leukemia (CLL) is the most common human leukemia. Deregulation of the T-cell leukemia/lymphoma 1 oncogene (
TCL1
) in mouse B cells causes a CD5
+
leukemia similar to aggressive human CLL. To examine the mechanisms by which Tcl1 protein exerts its oncogenic activity in B cells, we performed proteomics experiments to identify its interacting partners. We found that Tcl1 physically interacts with de novo DNA methylthansferases Dnmt3A and Dnmt3B. We further investigated the effects of Tcl1 up-regulation on the enzymatic activity of Dnmt3A and found that Tcl1 overexpression drastically inhibits Dnmt3A function. In addition, B cells from
TCL1
transgenic mice showed a significant decrease in DNA methylation compared with WT controls. Similarly, CLL samples with high Tcl1 expression showed a decrease in DNA methylation compared with CLL samples with low Tcl1 expression. Given the previous reports of inactivating mutations of
DNMT3A
in acute myelogenous leukemia and myelodysplastic syndrome, our results suggest that inhibition of de novo DNA methylation may be a common oncogenic mechanism in leukemogenesis.
Bilingual children’s gesture use
Authors: Smithson Lisa , Nicoladis Elena , Marentette Paula
Published: January 2012

Previous studies have shown that bilinguals use more manual gestures than monolinguals (Pika et al., 2006; Nicoladis et al., 2009), suggesting that gestures may facilitate lexical retrieval or may reduce the cognitive load on working memory during speech production. In this study, we tested the generalizability of these findings by comparing the use of gestures in three groups of children (English monolinguals, Mandarin Chinese-English bilinguals, and French-English bilinguals) between 7 and 10 years of age as they retold two short stories about a cartoon. The bilingual children were asked to retell narratives in both languages. The results showed that the French-English bilinguals used significantly more gestures than the Chinese-English bilinguals. With respect to gesture rates accompanying speech in English, the monolinguals did not differ from either bilingual group. The bilingual children’s use of gestures was generally not correlated with our measures of working memory (narrative length and speech rate). These results suggest that culture may be a more important determiner of gesture rate than bilingualism and/or working memory capacity.
Stress fibers guide focal adhesions to maturity
Authors: Short Ben
Published: January 2012

Study suggests that actin bundles serve as templates for adhesion growth.
Crucial role of SLP-76 and ADAP for neutrophil recruitment in mouse kidney ischemia-reperfusion injury
Authors: Block Helena , Herter Jan M. , Rossaint Jan , Stadtmann Anika , Kliche Stefanie , Lowell Clifford A. , Zarbock Alexander
Published: January 2012

Neutrophils trigger inflammation-induced acute kidney injury (AKI), a frequent and potentially lethal occurrence in humans. Molecular mechanisms underlying neutrophil recruitment to sites of inflammation have proved elusive. In this study, we demonstrate that SLP-76 (SH2 domain–containing leukocyte phosphoprotein of 76 kD) and ADAP (adhesion and degranulation promoting adaptor protein) are involved in E-selectin–mediated integrin activation and slow leukocyte rolling, which promotes ischemia-reperfusion–induced AKI in mice. By using genetically engineered mice and transduced Slp76−/− primary leukocytes, we demonstrate that ADAP as well as two N-terminal–located tyrosines and the SH2 domain of SLP-76 are required for downstream signaling and slow leukocyte rolling. The Tec family kinase Bruton tyrosine kinase is downstream of SLP-76 and, together with ADAP, regulates PI3Kγ (phosphoinositide 3-kinase–γ)- and PLCγ2 (phospholipase Cγ2)-dependent pathways. Blocking both pathways completely abolishes integrin affinity and avidity regulation. Thus, SLP-76 and ADAP are involved in E-selectin–mediated integrin activation and neutrophil recruitment to inflamed kidneys, which may underlie the development of life-threatening ischemia-reperfusion–induced AKI in humans.
THREE-MINUTE OSCILLATIONS ABOVE SUNSPOT UMBRA OBSERVED WITH THE SOLAR DYNAMICS OBSERVATORY/ATMOSPHERIC IMAGING ASSEMBLY AND NOBEYAMA RADIOHELIOGRAPH
Authors: Reznikova V. E. , Shibasaki K. , Sych R. A. , Nakariakov V. M.
Published: January 2012

Three-minute oscillations over a sunspot's umbra in AR 11131 were observed simultaneously in UV/EUV emission by the Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) and in radio emission by the Nobeyama Radioheliograph (NoRH). We use 24 hr series of SDO and 8 hr series of NoRH observations to study spectral, spatial, and temporal variations of pulsations in the 5–9 mHz frequency range at different layers of the solar atmosphere. High spatial and temporal resolution of SDO/AIA in combination with long-duration observations allowed us to trace the variations of the cutoff frequency and spectrum of oscillations across the umbra. We found that higher frequency oscillations are more pronounced closer to the umbra's center, while the lower frequencies concentrate on the peripheral parts. We interpreted this discovery as a manifestation of variation of the magnetic field inclination across the umbra at the level of temperature minimum. Possible implications of this interpretation for the diagnostics of sunspot atmospheres are discussed.
Effects of Sb addition on ZnO grain growth and the electrical characteristics of Ba-added-Bi-based ZnO varistors
Authors: Fukumori A , Kubota A , Sato Y , Yoshikado S
Published: January 2012

The varistor voltage increases as the number of ZnO grain boundaries between electrodes increases. Therefore, in order to fabricate varistors with low varistor voltages, it is necessary to reduce the number of ZnO grain boundaries between electrodes. The present study uses this method for increasing the ZnO grain size. With the goal of fabricating varistors with low varistor voltages, the effect on the ZnO grain size of adding Sb to Bi- Ba-Co-Mn-added ZnO varistors was investigated. Ba was added in order to increase the ZnO grain size, and Sb was added in order to achieve a uniform ZnO grain size without reducing the grain size. The addition of a small amount of Sb reduced the formation of ZnO grains having a smaller grain size, and the addition of 0.02 mol% Sb to the 0.5-mol%-Bi- and 0.5 mol% Ba added ZnO varistor exhibited a low varistor voltage of approximately 31 V/mm and the highest resistance to electrical degradation, because compounds containing both Ba and Mn do not form at grain boundaries between ZnO grains.
Effects of Sb, Zr, and Y addition on the electrical characteristics of Bi-based ZnO varistors
Authors: Watanabe T , Tokoro Y , Sato Y , Yoshikado S
Published: January 2012

The effects of adding Sb, Zr, and Y to a Bi–Mn–Co–Si–Cr–Ni-added ZnO varistor (with the same composition as a commercial varistor) on the varistor voltage, leakage current, and resistance to electrical degradation were investigated. Both the varistor voltage and the nonlinearity index of the voltage–current characteristics a before electrical degradation for samples added 1.0 mol% ZrO2and 1.0 mol% Y2O3were maximized at approximately 1.0 mol% Sb2O3and decreased rapidly when the amount of Sb2O3exceeded more than about 1.0 mol%. Samples added 1.0 mol% ZrO2, and 1.0 mol% Y2O3, and less than 0.75 mol% Sb2O3had a comparable leakage current to samples added neither ZrO2nor Y2O3. Sb is an important element that is necessary to obtain a high varistor voltage, a low leakage current, and an excellent resistance to electrical degradation. However, the same varistor voltage can be obtained by adding Y and reducing the amount of Sb2O3added.
Synthesis and characterization of poly(sodium acrylate)/ bentonite superabsorbent composite
Authors: Xie Yiming , Wei Yuelin , Huang Yunfang , Lin Jianming , Wu Jihuai
Published: January 2012

Poly(sodium acrylate)/bentonite superabsorbent composite with water absorbency 1562 g·g−1was synthesized by inverse suspension polymerization. The introduction of bentonite improves the water absorbency and facilitates the particle size even distribution of the composite. The network structure in the superabsorbent hydrogel is confirmed.
Effect of pH on formation of γ-MnO2from Zn-bearing MnSO4solution
Authors: Liu C X , Zhang L Z , Xiang L
Published: January 2012

Manganese dioxide has attracted much attention owing to its distinctive properties. A facile method was developed to synthesisγ-MnO2by the reaction of Na2S2O8with Zn-bearing MnSO4, keeping the molar ratio of Mn to S as 1:2-4. The oxidation of Mn2+increased from 62.3% to 99.9% with the increase of the final solution pH from 0.55 to 4.45. The needlelikeγ-MnO2particles with a length of 200-500 nm and a diameter of 10-30 nm were synthesized in the initial solution pH range of 3.5-4.0.γ-MnO2particles with poor crystallinity and porous morphology were synthesized in the initial solution pH range of 6.0-6.5. The Zn2+adsorption capacities of theγ-MnO2formed at initial pH = 3.5 and pH = 6.0 were 131.8 mg.g−1and 527.4 mg.g−1, respectively.
Application of doped rare-earth oxide TiO2:(Tm3+, Yb3+) in dye-sensitized solar cells
Authors: Xie Guixiang , Wei Yuelin , Fan Leqing , Wu Jihuai
Published: January 2012

Tm3+and Yb3+are codoped into TiO2film in a dye-sensitized solar cell (DSSC). The emission and excitation spectra of TiO2:(Tm3+, Yb3+) power shows that the rare-earth ions possess up-conversion luminescence function, which results in harvesting more incident light and increasing photocurrent for the DSSC. On the other hand, owing to the p-type doping effect by Tm3+and Yb3+, the photovoltage of the DSSC is enhanced. Under a simulated solar light irradiation of 100 mW·cm−2, a DSSC containing Tm3+/Yb3+achieves a conversion efficiency of 7.05 %, which is increased by 10.0% compared with a DSSC lacking Tm3+/Yb3+.
Effect of transition metal elements addition on the properties of nitrogen-doped TiO2photocatalysts
Authors: Li H , Zhang P , Yin S , Wang Y , Dong Q , Guo C , Sato T
Published: January 2012

Nitrogen-doped TiO2(TiO2−xNy) nanoparticles with and without adding the transition metal ions, such as Co+and Ni+, were synthesized by thermohydrolysis of TiCl3. The samples were characterized by X-ray diffraction, specific surface area determination, UV-vis diffuse reflectance spectroscopy. The photocatalytic activity of the sample was investigated by employing the oxidative destruction of nitric oxide as a probe reaction using a continuously flowing gases-solid system. Although the doping of transition metal ion in the lattice of titania was not useful to improve the photocatlytic activity, loading of transition metal oxides on the surface of titania resulted in an improvement of the photoreactivity of the nitrogen-doped TiO2. The beneficial effect was explained by an increased separation efficiency of the photogenerated electron-hole pairs.
Comparison of malleable stylet and reusable and disposable bougies by paramedics in a simulated difficult intubation
Authors: Gregory P. , Woollard M. , Lighton D. , Munro G. , Jenkinson E. , Newcombe R. G. , O’Meara P. , Hamilton L.
Published: January 2012

In a randomised crossover study, 60 ambulance paramedics attempted tracheal intubation of a manikin model of a Cormack and Lehane grade 3/4 view using a Portex stylet, Portex and Frova single‐use bougies, and a Portex reusable bougie. Tracheal intubation within 30 s was achieved by 34/60 (57%) using the stylet, 18/60 (30%) using a Portex single‐use bougie, 16/60 (27%) using a Frova single‐use bougie and 5/60 (8%) using a Portex reusable bougie. The proportion intubating within 30 s was significantly higher with the stylet compared with any bougie (p < 0.001), but significantly lower with a Portex reusable bougie than any other device (p < 0.004). Participants rated the Portex reusable bougie as significantly more difficult to use than the other devices (p < 0.001). There was no evidence of a relationship between previous experience and success rate for any device.
Distinct temporal patterns of immediate asthmatic reactions due to high‐ and low‐molecular‐weight agents
Authors: Malo J.‐L. , Ghezzo H. , L'Archevêque J.
Published: January 2012

Background

Exposure to occupational agents can cause immediate asthmatic reactions.

Objective

It can be hypothesized that the pattern of immediate reactions is different for high (HMW)‐ and low‐molecular‐weight (LMW) agents. To test this, we studied the temporal features of reactions in workers who underwent specific inhalation challenges for possible occupational asthma.

Methods

We examined 467 immediate reactions due to HMW (n = 248, 53%) and LWW (n = 219, 47%) agents in regards to timing of the maximum reaction and recovery.

Results

The median duration of exposure to elicit significant immediate reactions was comparable for HMW and LMW agents (15 min). The median maximum fall in FEV
1 occurred after 20 min for LMW by comparison with 10 min for HMW agents (P < 0.001). The median timing of recovery of FEV
1 to 10% baseline was shorter for HMW (60 min) than for LMW (90 min) agents (P < 0.01), and significantly more subjects recovered to 10% baseline (89.5%) for HMW than for LMW agents (72.6%) (P < 0.001). Confounding variables such as age, atopy, baseline airway calibre and the maximum fall in FEV
1 at the time of the immediate reaction did not alter the significant effect of the nature of the agent per se. Immediate reactions were followed by a late asthmatic reaction more often in the case of LMW (37.3%) than HMW (26.2%) agents (P < 0.05). Significant changes in non‐specific bronchial responsiveness were significantly (P = 0.02) more frequent after reactions to LMW (31.9%) than to HMW (21.4%) agents. We found similar trends by comparing reactions to flour (n = 113), the principal cause of reactions to HMW agents, and diisocyanates (n = 111), the principal LMW agent.

Conclusions and Clinical Relevance

This study shows distinct patterns for immediate reactions due to occupational agents. These results can provide useful guidelines for performing specific inhalation challenges and improve the safety of the procedure.
Effective elimination of subharmonic ghost events from vibroseis data
Authors: Stiller M. , Jaeckel K.‐H. , Weber M.
Published: January 2012

Harmonic or subharmonic noise is often present in vibroseis data as reverberation‐like, laterally coherent bands occurring parallel to and before or after, the main events. Such periodic noise is typically generated during the standard correlation process when the actual source signal travelling through the subsurface is, for whatever reason, different from the desired source signal, i.e., the pilot‐sweep controlling the baseplate and used for correlation. A typical cause can be that harmonic or subharmonic frequency partials are generated in addition to the vibroseis sweep's desired fundamental frequencies. These harmonics produce strong ‘ghost events’ during correlation of the geophone trace with the pilot‐sweep, originating from additional correlations between the fundamental and harmonic frequencies. Especially subharmonic ‘ghosts’ will overlap with ‘good’ fundamental signals, since for typically used up‐sweeps they are folded to later traveltimes, where the signal/noise‐ratio is already lower, thus aggravating or preventing a reliable interpretation of possible later reflections.

Here, a method is introduced to remove these unwanted noise trains (with only negligible impact on the fundamental signal) by transforming the seismogram traces into a so‐called ‘(sub)harmonic domain’. In this domain, the respective harmonic noise portions are focused and separated from the fundamental signals, enabling easier detection and appropriate suppression. After back‐transformation to the x‐T domain, the records are free from the corresponding harmonic contamination and can then be processed as usual. The method operates in a data‐driven fashion, i.e., the traces are not uniformly processed but are processed depending upon their actual (sub)harmonic content. The decontamination procedure can be applied universally, i.e., to uncorrelated/correlated and/or vertically unstacked/stacked data either in a manual, semiautomated or fully automated manner. The method works perfectly for synthetic vibroseis traces with or without harmonic/subharmonic portions. The application to real, crustal‐scale vibroseis records that were acquired in 2006 in the Dead Sea region, Israel and that were severely contaminated by subharmonic ground‐roll ghosts covering reflectivity from the basement to the Moho, shows the robustness and success of the presented method.