bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Holocene moss species preserved in lake sediment core and the present moss diversity at Schirmacher Oasis, Antarctica
Authors: Singh S.M. , Ochyra R. , Pednekar S.M. , Asthana R. , Ravindra R. 
Published: April 2012

AbstractThe sub-fossil mossPohlia nutansis recorded from lake sediment cores at Schirmacher Oasis, Dronning Maud Land, Antarctica. It was isolated from 160–162 cm depth of a sediment core. Radiocarbon (14C) dates by accelerator mass spectrometry confirmed its age to be 10.65 kyrbp. The preserved Holocene sub-fossil moss includes delicate leaves, axes and rhizoids and matches perfectly the extant specimens ofP. nutans.This is the first record of this sub-fossil from Dronning Maud Land, although the species is common as present-day flora in other parts of the Antarctic. The present status of the moss flora of Schirmacher Oasis is also discussed, including its diversity, ecology and biogeography.
A 1.2 V 15–32 GHz low-power single-balanced gate mixer with a miniature rat-race hybrid
Authors: Chen Chung-Chun , Lien Chun-Hsien , Tsao Hen-Wai , Wang Huei 
Published: April 2012

A 15–32 GHz miniature single-balanced gate mixer is proposed and analyzed. It achieves a smaller chip area with acceptable conversion gain and port-to-port isolation. In addition, the design procedure is described in detail. This mixer, fabricated in 90 nm digital CMOS technology, demonstrates a measured conversion loss of 1 dB and higher than 30 dB RF-to-LO port isolation from 17 to 32 GHz, at a local oscillator (LO) driver power of −4.3 dBm. The total dc power consumption is only 6 mW from a 1.2 V supply, including output buffer. The low dc power consumption and LO driver power reduce the power budget, and the proposed miniature rat-race hybrid facilitates integration in a receiver.
Emission and transport of cesium‐137 from boreal biomass burning in the summer of 2010
Authors: Strode Sarah A. , Ott Lesley E. , Pawson Steven , Bowyer Theodore W. 
Published: April 2012

While atmospheric concentrations of cesium‐137 (137Cs) have decreased since the nuclear testing era, resuspension of 137Cs during biomass burning provides an ongoing emission source. The summer of 2010 was an intense biomass burning season in western Russia, with high levels of particulate matter impacting air quality and visibility. A radionuclide monitoring station in western Russia shows enhanced airborne 137Cs concentrations during the wildfire period. Since 137Cs binds to aerosols, satellite observations of aerosols and fire occurrences can provide a global‐scale context for 137Cs emissions and transport during biomass burning events. We demonstrate that high values of the Moderate Resolution Imaging Spectroradiometer aerosol optical depth coincide with detections of 137Cs, and use the relationship between 137Cs and aerosols to model 137Cs based on organic carbon emissions and transport with the Goddard Earth Observing System, version 5 model. The model's boreal biomass burning tracer explains approximately half of the daily variability in detected 137Cs concentrations at a monitoring station in western Russia. Constraining the model with the station observations, we calculate 137Cs emissions of 1.5 × 1012 Bq from biomass burning north of 40° in July and August 2010. The emissions and subsequent deposition lead to a small northward redistribution of 137Cs.
Amplification of whistler‐mode hiss inside the plasmasphere
Authors: Chen Lunjin , Li Wen , Bortnik Jacob , Thorne Richard M. 
Published: April 2012

Chorus generated outside the plasmasphere has been suggested to be the source of plasmaspheric hiss. A detailed evaluation of the propagation and Landau damping of chorus waves can account for most of the properties of dayside hiss, but the intensity is underestimated by 10–20 dB compared to the observed hiss intensity. We show that this important discrepancy is due to the neglect of cyclotron resonant growth inside the plasmasphere. Careful modeling of the access of chorus to form an embryonic source outside the plasmapause, together with internal amplification inside the plasmasphere can account for the spectral intensity of dayside plasmaspheric hiss.
Observations of kinetic ballooning/interchange instability signatures in the magnetotail
Authors: Panov E. V. , Sergeev V. A. , Pritchett P. L. , Coroniti F. V. , Nakamura R. , Baumjohann W. , Angelopoulos V. , Auster H. U. , McFadden J. P. 
Published: April 2012

Stimulated by a recent study of a kinetic ballooning/interchange instability by Pritchett and Coroniti (2010), we present THEMIS events that confirm the predictions of this mechanism. In these events the probes were situated in the plasma sheet at 11 Re, near the presumed location of a B minimum. Prior to substorm onset, they observed strong magnetic oscillations with periods 20–100 s and δBX about 10–20 nT. Associated with these were oscillations of the electric field δEY ∼ 1 mV/m and the field‐aligned electron velocity of several hundreds of km/s. No comparable perturbations in the ion velocity were observed. For two cases cross‐correlation analyses proved duskward propagation of the elongated spatial structures with a cross‐tail width of a few ion gyroradii and a propagation velocity of about the ion drift velocity. In one case THEMIS probes confirmed a sausage‐like geometry of the structures.
Integration of Co-expression Networks for Gene Clustering
Authors: Bhattacharyya Malay , Bandyopadhyay Sanghamitra 
Published: April 2012

AbstractSimultaneous overexpression or underexpression of multiple genes, used in various forms as probes in the high-throughput microarray experiments, facilitates the identification of their underlying functional proximity. This kind of functional associativity (or conversely the separability) between the genes can be represented proficiently using co-expression networks. The extensive repository of diversified microarray data encounters a recent problem of multi-experimental data integration for the aforesaid purpose. This paper highlights a novel integration method of gene co-expression networks, based on the search for their consensus network, derived from diverse microarray experimental data for the purpose of clustering. The proposed methodology avoids the bias arising from missing value estimation. The method has been applied on microarray datasets arising from different category of experiments to integrate them. The consensus network, thus produced, reflects robustness based on biological validation.
Trapped and Escaping Orbits in an Axially Symmetric Galactic-Type Potential
Authors: Zotos Euaggelos E. 
Published: April 2012

AbstractIn the present article, we investigate the behavior of orbits in a time-independent axially symmetric galactic-type potential. This dynamical model can be considered to describe the motion in the central parts of a galaxy, for values of energies larger than the energy of escape. We use the classical surface-of-section method in order to visualize and interpret the structure of the phase space of the dynamical system. Moreover, the Lyapunov characteristic exponent is used in order to make an estimation of the degree of chaoticity of the orbits in our galactic model. Our numerical calculations suggest that in this galactic-type potential there are two kinds of orbits: (i) escaping orbits and (ii) trapped orbits, which do not escape at all. Furthermore, a large number of orbits of the dynamical system display chaotic motion. Among the chaotic orbits, there are orbits that escape quickly and also orbits that remain trapped for vast time intervals. When the value of a test particle's energy slightly exceeds the energy of escape, the number of trapped regular orbits increases as the value of the angular momentum increases. Therefore, the extent of the chaotic regions observed in the phase plane decreases as the energy value increases. Moreover, we calculate the average value of the escape period of chaotic orbits and try to correlate it with the value of the energy and also with the maximum value of the z component of the orbits. In addition, we find that the value of the Lyapunov characteristic exponent corresponding to each chaotic region for different values of energy increases exponentially as the energy increases. Some theoretical arguments are presented in order to support the numerically obtained outcomes.
Torque measurements reveal sequence-specific cooperative transitions in supercoiled DNA
Authors: Oberstrass Florian C. , Fernandes Louis E. , Bryant Zev 
Published: April 2012

B-DNA becomes unstable under superhelical stress and is able to adopt a wide range of alternative conformations including strand-separated DNA and Z-DNA. Localized sequence-dependent structural transitions are important for the regulation of biological processes such as DNA replication and transcription. To directly probe the effect of sequence on structural transitions driven by torque, we have measured the torsional response of a panel of DNA sequences using single molecule assays that employ nanosphere rotational probes to achieve high torque resolution. The responses of Z-forming d(pGpC)

n

sequences match our predictions based on a theoretical treatment of cooperative transitions in helical polymers. “Bubble” templates containing 50–100 bp mismatch regions show cooperative structural transitions similar to B-DNA, although less torque is required to disrupt strand–strand interactions. Our mechanical measurements, including direct characterization of the torsional rigidity of strand-separated DNA, establish a framework for quantitative predictions of the complex torsional response of arbitrary sequences in their biological context.
Low-temperature UV photoluminescence of ion beam synthesized Si nanoclusters embedded in Si
Authors: Sahu G , Lenka H P , Mahapatra D P , Rout B , Das M P 
Published: April 2012

Abstract
Ultraviolet (UV) photoluminescence (PL) data taken on a double Au implanted Si matrix are reported. This has been studied over a wide temperature range of 28–220 K. At low temperature, the spectrum shows four peaks corresponding to a zero-phonon line (ZPL) and three low-energy phonon-assisted lines. At 28 K the ZPL has an energy of 3.362 eV with a lifetime of ∼240 ps suggesting transitions across a direct gap. The temperature variation of the ZPL intensity indicates an activation energy ∼10 meV comparable to the binding energy of excitons in crystalline Si (c-Si). For T > 100 K, it shows a redshift which can be understood as coming from exciton–phonon interaction. At lower temperatures the corresponding line broadening shows evidence of interaction with low-energy phonons of average energy ∼7 meV as suggested earlier. All the above results indicate the emission to be coming from Si nanoclusters (NCs) embedded in the matrix.
Fabrication and surface-modification of implantable microprobes for neuroscience studies
Authors: Cao H , Nguyen C M , Chiao J C 
Published: April 2012

Abstract
In this work implantable micro-probes for central nervous system (CNS) studies were developed on silicon and polyimide substrates. The probes which contained micro-electrode arrays with different surface modifications were designed for implantation in the CNS. The electrode surfaces were modified with nano-scale structures that could greatly increase the active surface area in order to enhance the electrochemical current outputs while maintaining micro-scale dimensions of the electrodes and probes. The electrodes were made of gold or platinum, and designed with different sizes. The silicon probes were modified by silicon nanowires fabricated with the vapor–liquid–solid mechanism at high temperatures. With polyimide substrates, the nanostructure modification was carried out by applying concentrated gold or silver colloid solutions onto the micro-electrodes at room temperature. The surfaces of electrodes before and after modification were observed by scanning electron microscopy. The silicon nanowire-modified surface was characterized by cyclic voltammetry. Experiments were carried out to investigate the improvement in sensing performance. The modified electrodes were tested with H
2
O
2, electrochemical L-glutamate and dopamine. Comparisons between electrodes with and without nanostructure modification were conducted showing that the modifications have enhanced the signal outputs of the electrochemical neurotransmitter sensors.
Fabrication of micro accelerometer and magnetoresistive sensor directly on a ceramic substrate
Authors: Aoyagi Seiji 
Published: April 2012

Abstract
Micro-electro-mechanical systems (MEMS) sensors have movable parts: thus, it is difficult to handle them at fabrication because of the possibility of fracture. If a MEMS sensor could be fabricated not only on a silicon substrate but also on a ceramic substrate, which can be used for a package of the end product, the above-mentioned problem about handling would be solved, and its fabrication cost would be reduced. In this presentation, as demonstrations of the sensors directly fabricated on a ceramic package, an accelerometer and a magnetoresistive (MR) sensor are focused on. A micro accelerometer is proposed, which consists of a proof mass and ferroelectric substrate under it. A screen-printed barium titanate (BTO) film on an alumina substrate was employed as ferroelectrics. The sensitivity of the fabricated accelerometer was 0.1 pF
g
−1. A triaxis MR sensor is proposed, which detects not only x- and y-axes’ magnetic field intensities but also that of the z-axis. Namely, not only azimuth but also angle of elevation of the sensor can be detected from triaxis components of the geomagnetic field. A permalloy (FeNi) plate is stood aside from the MR element. The plate distorts magnetic field and generates the x- (or y-) component from the originally z-directional field. A triaxis geomagnetic field was successfully detected by the fabricated sensor.
hOGG1 Ser326Cys polymorphism is associated with risk of bladder cancer in a Chinese population: A case‐control study
Authors: Ma Lan , Chu Haiyan , Wang Meilin , Shi Danni , Zhong Dongyan , Li Pu , Tong Na , Yin Changjun , Zhang Zhengdong 
Published: April 2012

Human oxoguanine glycosylase 1 (hOGG1) is a DNA repair enzyme, which plays important roles in the base excision repair (BER) pathway. Several studies reported a common polymorphism Ser326Cys (rs1052133) in hOGG1, which conferred the susceptibility of bladder cancer. We hypothesized that the polymorphism is associated with risk of bladder cancer in a Chinese population. In a case‐control study of 1050 histologically confirmed bladder cancer patients and 1404 age and sex matched healthy controls, we genotyped the hOGG1 Ser326Cys polymorphism using TaqMan technology and assessed its association with bladder cancer risk. We found that the hOGG1 Ser/Cys + Ser/Ser genotypes were associated with a significantly increased risk of bladder cancer (adjusted odds ratio [OR] = 1.19, 95% confidence interval [CI] = 1.01–1.41), compared with the Cys/Cys genotype. Furthermore, the increased risk was more pronounced among subjects over age 65 years (OR = 1.31, 95% CI = 1.04–1.66), male subjects (OR = 1.21, 95% CI = 1.00–1.47), ever smokers (OR = 1.29, 95% CI = 1.00–1.68) and heavy smokers (>20 pack‐years) (OR = 1.45, 95% CI = 1.03–2.04). No significant association was observed in the stratification of tumor grade and tumor stage for bladder cancer. In conclusion, our results suggest that hOGG1 Ser326Cys polymorphism may contribute to the susceptibility to bladder cancer in a Chinese population. (Cancer Sci 2012; 103: 1215–1220)
The combined effect of very low nicotine content cigarettes, used as an adjunct to usual Quitline care (nicotine replacement therapy and behavioural support), on smoking cessation: a randomized controlled trial
Authors: Walker Natalie , Howe Colin , Bullen Chris , Grigg Michele , Glover Marewa , McRobbie Hayden , Laugesen Murray , Parag Varsha , Whittaker Robyn 
Published: April 2012

ABSTRACTAim  To determine the combined effect of very low nicotine content (VLNC) cigarettes and usual Quitline care [nicotine replacement therapy (NRT) and behavioural support] on smoking abstinence, in smokers motivated to quit.Design  Single‐blind, parallel randomized trial.Setting  New Zealand.Participants  Smokers who called the Quitline for quitting support were randomized to either VLNC cigarettes to use whenever they had an urge to smoke for up to 6 weeks after their quit date, in combination with usual Quitline care (8 weeks of NRT patches and/or gum or lozenges, plus behavioural support) or to usual Quitline care alone.Measurements  The primary outcome was 7‐day point‐prevalence smoking abstinence 6 months after quit day. Secondary outcomes included continuous abstinence, cigarette consumption, withdrawal, self‐efficacy, alcohol use, serious adverse events and views on the use of the VLNC cigarettes at 3 and 6 weeks and 3 and 6 months.Findings  A total of 1410 participants were randomized (705 in each arm), with a 24% loss to follow‐up at 6 months. Participants in the intervention group were more likely to have quit smoking at 6 months compared to the usual care group [7‐day point‐prevalence abstinence 33 versus 28%, relative risk (RR) = 1.18, 95% confidence interval (CI): 1.01, 1.39, P = 0.037; continuous abstinence 23 versus 15%, RR = 1.50, 95% CI: 1.20, 1.87, P = 0.0003]. The median time to relapse in the intervention group was 2 months compared to 2 weeks in the usual care group (P < 0.0001).Conclusions  Addition of very low nicotine content cigarettes to standard Quitline smoking cessation support may help some smokers to become abstinent.
Pregnancy outcome after gestational exposure to erythromycin – a population‐based register study from Norway
Authors: Romøren Maria , Lindbæk Morten , Nordeng Hedvig 
Published: April 2012

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT• It has generally been regarded as safe to take erythromycin during pregnancy. A recent study from Sweden found that erythromycin exposure in the first trimester was associated with congenital cardiovascular defects. The results led to warnings against using erythromycin in the first trimester from both the Swedish and Norwegian governments.WHAT THIS STUDY ADDS• This large, population‐based register study did not find that erythromycin or macrolide use in pregnancy was significantly associated with congenital malformations, cardiovascular malformations or any other specific malformation.AIMS Erythromycin is a macrolide antibiotic indicated for respiratory tract infections, genital chlamydia and skin infections. It has recently been suggested that erythromycin use in the first trimester of pregnancy can increase the risk of congenital cardiovascular malformations. This study aimed to determine whether erythromycin exposure in the first trimester is associated with cardiovascular or other malformations.METHODS We studied 180 120 women in Norway who were pregnant during 2004–2007. Data on all live births stillbirths and induced abortions after 12 gestational weeks from The Medical Birth Registry of Norway (MBRN) were linked to information from the Norwegian prescription database (NorPD). We compared the pregnancy outcomes of women who had taken erythromycin (n= 1786, 1.0%), penicillin V (n= 4921, 2.7%) or amoxicillin (n= 1599, 0.9%) in their first trimester with outcomes of women who had not taken any systemic antibiotics (n= 163 653, 90.9%) during this period.RESULTS The risk of cardiovascular malformations was not significantly different with or without exposure to erythromycin in the first trimester (adjusted OR = 1.2 [95% CI 0.8, 1.8]) or in the most vulnerable period of heart formation (adjusted OR = 1.6 [95% CI 0.9–3.0]). Sub‐analyses showed that the risk for any specific malformations was not increased with erythromycin, macrolides, penicillin V or amoxicillin compared with no antibiotic use in first trimester.CONCLUSIONS This large, population‐based register study did not find that exposure to erythromycin or macrolides in the first trimester of pregnancy was associated with fetal cardiovascular or other malformations. These results suggest that the risk of erythromycin use during early pregnancy, if any, is low.
Human bone marrow stromal cells simultaneously support B and T/NK lineage development from human haematopoietic progenitors: a principal role for flt3 ligand in lymphopoiesis
Authors: Nakamori Yoshiki , Liu Bing , Ohishi Kohshi , Suzuki Kei , Ino Kazuko , Matsumoto Takeshi , Masuya Masahiro , Nishikawa Hiroyoshi , Shiku Hiroshi , Hamada Hirofumi , Katayama Naoyuki 
Published: April 2012

SummaryThe regulation of human early lymphopoiesis remains unclear. B‐ and T‐lineage cells cannot develop simultaneously with conventional stromal cultures. Here we show that telomerized human bone marrow stromal cells supported simultaneous generation of CD19+CD34lo/−CD10+cyCD79a+CD20+/−VpreB− pro‐B cells and CD7+CD34+ CD45RA+CD56−cyCD3− early T/Natural Killer (NK) cell precursors from human haematopoietic progenitors, and the generation of both lymphoid precursors was promoted by flt3 ligand (flt3L). On the other hand, stem cell factor or thrombopoietin had little or no effect when used alone. However, both acted synergistically with flt3L to augment the generation of both lymphoid precursors. Characteristics of these lymphoid precursors were evaluated by gene expression profiles, rearrangements of IgH genes, or replating assays. Similar findings were observed with primary human bone marrow stromal cells. Notably, these two lymphoid‐lineage precursors were generated without direct contact with stromal cells, indicating that early B and T/NK development can occur, at least in part, by stromal cell‐derived humoral factors. In serum‐free cultures, flt3L elicited similar effects and appeared particularly important for B cell development. The findings of this study identified the potential of human bone marrow stromal cells to support human early B and T lymphopoiesis and a principal role for flt3L during early lymphopoiesis.
‘I am part of every decision’: client perceptions of engagement within a supportive housing child welfare programme
Authors: Farrell Anne F. , Luján Melissa L. , Britner Preston A. , Randall Kellie G. , Goodrich Samantha A. 
Published: April 2012

ABSTRACTThe majority of children in the child welfare system enter because of neglect and come from poor families with high rent burden, substandard housing and risk for homelessness. In this paper, we describe a model programme for families with dual vulnerability in housing and child welfare. Clients presented with a variety of parenting, substance use and/or mental health issues. The Supportive Housing for Families (SHF) programme prioritizes prompt family access to housing and related supports and operates from an intensive, family‐centred casework that promotes client engagement as a mechanism for change. We used a mixed methods approach that included the administration of Alpert and Britner's Parent Engagement Measure (quantitative) and open‐ended interviews (qualitative) with 41 parents involved in the child welfare system. Results indicate high levels of client engagement, with convergence across the formal measure and interview themes. SHF promoted client engagement through the swift provision of tangible resources, as well as caseworker resourcefulness and responsiveness. The Parent Engagement Measure performed well psychometrically. We compare findings with prior research and discuss implications, limitations and future directions.