bluuebunny/crossref_metadata_2025_split huggingface dataset:
Astrophysik: ROSAT und seine Nachfolger: Der Forschungssatellit ROSAT hat die Röntgenastronomie revolutioniert
Authors: Trümper Joachim 
Published: February 2013

AbstractMit mehr als acht Jahren, die zwischen dem “First Light” am 16./17. Juni 1990 und der letzten Beobachtung am 18. Dezember 1998 lagen, hat der Röntgensatellit ROSAT einen Langzeitrekord für Astronomiesatelliten in einer erdnahen Umlaufbahn aufgestellt. In dieser Zeit wurden nicht nur viele Entdeckungen gemacht. ROSAT hat auch den Röntgenhimmel einer sehr großen wissenschaftlichen Gemeinde erschlossen und den Weg bereitet für seine Nachfolger ABRIXAS, Chandra, XMM und Astro‐E.
A conserved threonine spring‐loads precursor for intein splicing
Authors: Dearden Albert K. , Callahan Brian , Roey Patrick Van , Li Zhong , Kumar Utsav , Belfort Marlene , Nayak Saroj K. 
Published: February 2013

AbstractProtein splicing is an autocatalytic process where an “intein” self‐cleaves from a precursor and ligates the flanking N‐ and C‐“extein” polypeptides. Inteins occur in all domains of life and have myriad uses in biotechnology. Although the reaction steps of protein splicing are known, mechanistic details remain incomplete, particularly the initial peptide rearrangement at the N‐terminal extein/intein junction. Recently, we proposed that this transformation, an N‐S acyl shift, is accelerated by a localized conformational strain, between the intein's catalytic cysteine (Cys1) and the neighboring glycine (Gly‐1) in the N‐extein. That proposal was based on the crystal structure of a catalytically competent trapped precursor. Here, we define the structural origins and mechanistic relevance of the conformational strain using a combination of quantum mechanical simulations, mutational analysis, and X‐ray crystallography. Our results implicate a conserved, but largely unstudied, threonine residue of the Ssp DnaE intein (Thr69) as the mediator of conformational strain through hydrogen bonding. Further, the strain imposed by this residue is shown to position the splice junction in a manner that enhances the rate of the N‐S acyl shift substantially. Taken together, our results not only provide fundamental understanding of the control of the first step of protein splicing but also have important implications in various biotechnological applications that require precursor manipulation.
Accuracy of GPS total electron content: GPS receiver bias temperature dependence
Authors: Coster A. , Williams J. , Weatherwax A. , Rideout W. , Herne D. 
Published: February 2013

AbstractHaving an accurate method to estimate and remove ionospheric effects is a major issue for low‐frequency radio astronomy arrays, as the ionosphere is one of their largest error terms. One way to estimate the ionosphere is to measure total electron content (TEC) using dual frequency global positioning system (GPS) signals. This technique uses the dispersive nature of the ionosphere, as both group and phase velocities are (to first order) dependent on the inverse square of the frequency and on TEC. Using these properties, TEC can be measured to a high degree of accuracy by computing the delay difference between signals at GPS's two frequencies (L1 = 1575.42 and L2 = 1227.6 MHz). Unfortunately, effects other than ionospheric dispersion also introduce differential delay differences. These additional differences, called biases, can be separated into those introduced by the satellite and those by the receiver. Receiver biases show the most significant variations, sometimes over intervals of hours. Changing temperature conditions at the receiver antenna, along the cable, or in the internal receiver hardware are thought to be responsible for some of these variations. We report here on an investigation of the temperature dependence of the GPS receiver bias. Our results show that for our particular receiver, antenna, and cable set‐up, a temperature‐dependent bias is clearly evident, and that this temperature dependence varies from receiver to receiver. When the receiver bias temperature dependence is removed, a noise level of 1–3 TEC units still remains in the bias estimation.
Analysis of dentin/enamel remineralization by a CPP‐ACP paste: AFM and SEM study
Authors: Poggio Claudio , Lombardini Marco , Vigorelli Paolo , Ceci Matteo 
Published: February 2013

SummaryThe aim of the present in vitro study was the evaluation of a CPP‐ACP paste on preventing dentin/enamel erosion produced by a soft drink; Atomic Force Microscopy and Scanning Electron Microscopy were used. Eighty extracted human incisors free of caries were selected and divided into four groups (each divided in two subgroups); group 1a: intact dentin; group 1b: dentin + soft drink; group 2a: intact dentin + CCP‐ACP paste; group 2b: dentin + soft drink + CCP‐ACP paste; group 3a: intact enamel; group 3b: enamel + soft drink; group 4a: intact enamel + CCP‐ACP paste; group 4b: enamel + soft drink + CCP‐ACP paste. The CPP‐ACP paste was applied for 3 min at 0, 8, 24, and 36 h. The surface of each dentin/enamel specimen was imaged by AFM (Rrms values were registered) and SEM. A statistical significant difference was recorded between groups 1b (dentin + soft drink) and 2b (dentin + soft drink + CCP‐ACP paste) and between groups 3b (enamel + soft drink) and 4b (enamel + soft drink + CCP‐ACP paste), suggesting that treatment of the specimens with the CPP‐ACP paste had a protective effect on enamel demineralization, which was more evident for enamel specimens. Under the limitations of the present in vitro study, it can be concluded that the application of a CPP‐ACP paste is effective on preventing dentin/enamel erosion produced by a soft drink. SCANNING 35:366–374, 2013. © 2013 Wiley Periodicals, Inc. SCANNING 35:???–???, 2013. © 2013 Wiley Periodicals, Inc.
Silver Nanoparticle Exposure Attenuates the Viability of Rat Cerebellum Granule Cells through Apoptosis Coupled to Oxidative Stress
Authors: Yin Nuoya , Liu Qian , Liu Jiyan , He Bin , Cui Lin , Li Zhuona , Yun Zhaojun , Qu Guangbo , Liu Sijin , Zhou Qunfang , Jiang Guibin 
Published: February 2013

AbstractThe impact of silver nanoparticles (AgNPs) on the central nervous system is a topic with mounting interest and concern and the facts remain elusive. In the current study, the neurotoxicity of commercial AgNPs to rat cerebellum granule cells (CGCs) and the corresponding molecular mechanism are closely investigated. It is demonstrated that AgNPs induce significant cellular toxicity to CGCs in a dose‐dependent manner without damaging the cell membrane. Flow cytometry analysis with the Annexin V/propidium iodide (PI) staining indicates that the apoptotic proportion of CGCs upon treatment with AgNPs is greatly increased compared to the negative control. Moreover, the activity of caspase‐3 is largely elevated in AgNP‐treated cells compared to the negative control. AgNPs are demonstrated to induce oxidative stress, reflected by the massive generation of reactive oxygen species (ROS), the depletion of antioxidant glutathione (GSH), and the increase of intracellular calcium. Histological examination suggests that AgNPs provoke destruction of the cerebellum granular layer in rats with concomitant activation of caspase‐3, in parallel to the neurotoxicity of AgNPs observed in vitro. Taken together, it is demonstrated for the first time that AgNPs substantially impair the survival of primary neuronal cells through apoptosis coupled to oxidative stress, depending on the caspase activation‐mediated signaling.
Hydrothermal Synthesis, Crystal Structure, and Luminescent Properties of Two Zinc(II) and Cadmium(II) 3D Metal‐­Organic Frameworks
Authors: Zhang Cheng‐Yan , Wang Ming‐Yan , Li Qiu‐Tong , Qian Bao‐Hua , Yang Xu‐Jie , Xu Xing‐You 
Published: February 2013

AbstractTwo zinc(II) and cadmium(II) metal‐organic frameworks with mixed ligands, {[Zn2(biim‐4)2(TDC)2]·2.5H2O}n (1) and {[Cd2(biim‐4)2(TDC)2·2H2O]}n (2) [biim‐4 = 1,1′‐(1,4‐butanediyl)bis(imidazole); H2TDC = thiophene‐2,5‐dicarboxylic acid], were hydrothermally synthesized. Both of them are characterized by elemental analysis, IR spectroscopy, and single crystal X‐ray diffraction. In 1, the four‐connected ZnII nodes are connected by four linear ligands extending into a 3D network, which further integrates a fivefold interpenetrating diamond 3D topological network and the free water molecules distribute in void space, whereas in 2, the CdII ions are in a distorted octahedral arrangement linked by TDC2– and biim‐4 ligands to construct a 3D framework. In topology analysis, C11 and C14 are simplified as 3‐connected nodes and the 3D framework displays a (3,5)‐connected net. Furthermore, the thermal and photoluminescent properties of 1 and 2 were also studied.
Parametric and Nonparametric Analysis of Life Courses: An Application to Family Formation Patterns
Authors: Bonetti Marco , Piccarreta Raffaella , Salford Gaia 
Published: February 2013

Abstract
We discuss a unified approach to the description and explanation of life course patterns represented as sequences of states observed in discrete time. In particular, we study life course data collected as part of the Dutch Fertility and Family Surveys (FFS) to learn about the family formation behavior of 1,897 women born between 1953 and 1962. Retrospective monthly data were available on each 18- to 30-year-old woman living either with or without children as single, married, or cohabiting. We first study via a nonparametric approach which factors explain the pairwise dissimilarities observed between life courses. Permutation distribution inference allows for the study of the statistical significance of the effect of a set of covariates of interest. We then develop a parametric model for the sequence-generating process that can be used to describe state transitions and durations conditional on covariates and conditional on having observed an initial segment of the trajectory. Fitting ofthe proposed model and the corresponding model selection process are based on the observed data likelihood. We discuss the application of the methods to the FFS.
Mouse models for lung cancer
Authors: Kwon Min-chul , Berns Anton 
Published: February 2013

Lung cancer is a devastating disease and a major therapeutic burden with poor survival rates. It is responsible for 30% of all cancer deaths. Lung cancer is strongly associated with smoking, although some subtypes are also seen in non‐smokers. Tumors in the latter group are mostly adenocarcinomas with many carrying mutations in the epidermal growth factor receptor (EGFR). Survival statistics of lung cancer are grim because of its late detection and frequent local and distal metastases. Although DNA sequence information from tumors has revealed a number of frequently occurring mutations, affecting well‐known tumor suppressor genes and proto‐oncogenes, many of the driver mutations remain ill defined. This is likely due to the involvement of numerous rather infrequently occurring driver mutations that are difficult to distinguish from the very large number of passenger mutations detected in smoking‐related lung cancers. Therefore, experimental model systems are indispensable to validate putative driver lesions and to gain insight into their mechanisms of action. Whereas a large fraction of these analyzes can be performed in cell cultures in vitro, in many cases the consequences of the mutations have to be assessed in the context of an intact organism, as this is the context in which the Mendelian selection process of the tumorigenic process took place and the advantages of particular mutations become apparent. Current mouse models for cancer are very suitable for this as they permit mimicking many of the salient features of human tumors. The capacity to swiftly re‐engineer complex sets of lesions found in human tumors in mice enables us to assess the contribution of defined combinations of lesions to distinct tumor characteristics such as metastatic behavior and response to therapy. In this review we will describe mouse models of lung cancer and how they are used to better understand the disease and how they are exploited to develop better intervention strategies.
Intracoelomic Acoustic Tagging of Juvenile Sockeye Salmon: Swimming Performance, Survival, and Postsurgical Wound Healing in Freshwater and during a Transition to Seawater
Authors: Collins Alison L. , Hinch Scott G. , Welch David W. , Cooke Steven J. , Clark Timothy D. 
Published: February 2013

AbstractJuvenile hatchery‐reared Sockeye Salmon Oncorhynchus nerka from Cultus Lake, British Columbia, were implanted during their smolt phase with one of three sizes of dummy acoustic tags to assess how tag burden (tag mass: body mass ratios ranging from 1.3% to 13.6% in air) influenced prolonged swimming performance, survival, and postsurgical wound healing in freshwater for up to 16.5 d and following a transition to seawater for 9 d. Tagged fish were compared with surgical shams and control fish (no tag, no surgery). Fish subjected to sham surgery treatments had mean swim times similar to those of control fish; however, tagged fish had a significantly lower probability of swimming the mean time of nontagged control fish. In addition, we found that the effect of tagging on swimming performance was exacerbated by tag burden and that higher tag burdens decreased the swimming performance of tagged individuals. Fish with tag burdens ≥8% had shorter swimming durations than fish with tag burdens <8%. The incisions of fish implanted with smaller tags healed more quickly than those of fish implanted with the largest tag. Overall, survival was high (≥95%) and in freshwater mortalities only occurred in fish that had tag burdens greater than 6%. These findings have important implications for studies using tagging technologies to examine the behavior and survival of migrating salmon smolts.
The Influence of Release Strategy and Migration History on Capture Rate of Oncorhynchus mykiss in a Rotary Screw Trap
Authors: Tattam Ian A. , Ruzycki James R. , Bayley Peter B. , Li Hiram W. , Giannico Guillermo R. 
Published: February 2013

Abstract
Rotary screw traps are used in rivers throughout the west coast of North America to capture emigrating juvenile salmonids. Calibrating the capture efficiency of each trap is essential for valid estimates of fish passage. We released PIT-tagged Oncorhynchus mykiss upstream of a rotary screw trap in the South Fork John Day River, Oregon, to estimate capture efficiency. We used three strategies for release of fish recently captured in the trap. We recaptured 28% of medium-sized fish (86–145 mm FL) and 14% of large-sized fish (146–230 mm FL) released during daylight 1.6 km upstream from the trap. We recaptured 33% of medium-sized fish and 17% of large-sized fish released during daylight 4.8 km upstream from the trap. We recaptured 42% of medium-sized fish and 23% of large-sized fish released at twilight 1.8 km upstream from the trap. A PIT tag antenna detected summer-tagged parr (which were PIT-tagged upstream 1–5 months before migration) as they approached the trap to evaluate potential bias from reduced recapture of recently trapped fish. We captured 53% of the medium-sized first-time migrants and 40% of the large-sized first-time migrants. Although average capture efficiencies of first-time migrants were greater than those from any of the recently trapped fish from the three release strategies, twilight releases of recently trapped fish were the least negatively biased, especially for medium-sized fish.
Received May 7, 2012; accepted December 6, 2012
Characteristics of Adolescent Psychiatric Inpatients with Early-Onset and Adolescent-Onset Disruptive Behavior
Authors: de Boer SjoukjeB.B. , Boon AlbertE. , Verheij Fop , Donker MarianneC. H. 
Published: February 2013

The main aim of this study was to identify factors that diagnosticians in clinical practice can use to differentiate between adolescents on the life-course-persistent and adolescence-limited pathways of antisocial behavior. In epidemiological research these subtypes could not be distinguished based on their disruptive behavior. Because this differentiation is important for choice of treatment for adolescent psychiatric inpatients with severe disruptive behavior, the purpose of the present study was to identify easily measurable characteristics present in adolescence that are associated with the pathways. Male and female adolescent psychiatric inpatients were divided into either early-onset (EO) ( n = 134) or adolescent-onset (AO) ( n = 69) disruptive behavior, based on the age at which professional care was required for disruptive behavior, referral to special education occurred, or criminal offences were first committed. The groups differed on several characteristics. No gender differences were found in these characteristics. Logistic regression analysis indicated that males with a history of physical abuse, who were referred by a youth care facility had the highest probability of being member of the EO group. These characteristics are reasonably easy to identify, may apply to other clinical samples as well, and may help clinicians to target their treatment.
Maximum sustained yield: a policy disguised as science
Authors: Finley Carmel , Oreskes Naomi 
Published: February 2013

Abstract
Finley, C. and Oreskes, N. 2013. Maximum sustained yield: a policy disguised as science. – ICES Journal of Marine Science, 70: 245–250. Overfishing is most commonly explained as an example of the tragedy of the commons, where individuals are unable to control their activities, leading to the destruction of the resource they are dependent on. The historical record suggests otherwise. Between1949 and 1958, the US State Department used fisheries science, and especially the concept of maximum sustained yield (MSY) as a political tool to achieve its foreign policy objectives. During the Cold War, the Department thought that if countries were allowed to restrict fishing in their waters, it might lead to restrictions on passage of military vessels. While there has been much criticism of MSY and its failure to conserve fish stocks, there has been little attention paid to the political context in which MSY was adopted.
In situ analysis of oxygen consumption and diffusive transport in high‐temperature acidic iron‐oxide microbial mats
Authors: Bernstein Hans C. , Beam Jacob P. , Kozubal Mark A. , Carlson Ross P. , Inskeep William P. 
Published: February 2013

SummaryThe role of dissolved oxygen as a principal electron acceptor for microbial metabolism was investigated within Fe(III)‐oxide microbial mats that form in acidic geothermal springs of Yellowstone National Park (USA). Specific goals of the study were to measure and model dissolved oxygen profiles within high‐temperature (65–75°C) acidic (pH = 2.7–3.8) Fe(III)‐oxide microbial mats, and correlate the abundance of aerobic, iron‐oxidizing Metallosphaera yellowstonensis organisms and mRNA gene expression levels to Fe(II)‐oxidizing habitats shown to consume oxygen. In situ oxygen microprofiles were obtained perpendicular to the direction of convective flow across the aqueous phase/Fe(III)‐oxide microbial mat interface using oxygen microsensors. Dissolved oxygen concentrations dropped from ∼ 50–60 μM in the bulk‐fluid/mat surface to below detection (< 0.3 μM) at a depth of ∼ 700 μm (∼ 10% of the total mat depth). Net areal oxygen fluxes into the microbial mats were estimated to range from 1.4–1.6 × 10−4 μmol cm−2 s−1. Dimensionless parameters were used to model dissolved oxygen profiles and establish that mass transfer rates limit the oxygen consumption. A zone of higher dissolved oxygen at the mat surface promotes Fe(III)‐oxide biomineralization, which was supported using molecular analysis of Metallosphaera yellowstonensis 16S rRNA gene copy numbers and mRNA expression of haem Cu oxidases (FoxA) associated with Fe(II)‐oxidation.
Isolation and physiological characterization of psychrophilic denitrifying bacteria from permanently cold Arctic fjord sediments (Svalbard, Norway)
Authors: Canion Andy , Prakash Om , Green Stefan J. , Jahnke Linda , Kuypers Marcel M. M. , Kostka Joel E. 
Published: February 2013

SummaryA large proportion of reactive nitrogen loss from polar sediments is mediated by denitrification, but microorganisms mediating denitrification in polar environments remain poorly characterized. A combined approach of most‐probable‐number (MPN) enumeration, cultivation and physiological characterization was used to describe psychrophilic denitrifying bacterial communities in sediments of three Arctic fjords in Svalbard (Norway). A MPN assay showed the presence of 103−106 cells of psychrophilic nitrate‐respiring bacteria g−1 of sediment. Fifteen strains within the Proteobacteria were isolated using a systematic enrichment approach with organic acids as electron donors and nitrate as an electron acceptor. Isolates belonged to five genera, including Shewanella, Pseudomonas, Psychromonas (Gammaproteobacteria), Arcobacter (Epsilonproteobacteria) and Herminiimonas (Betaproteobacteria). All isolates were denitrifiers, except Shewanella, which exhibited the capacity for dissimilatory nitrate reduction to ammonium (DNRA). Growth from 0 to 40°C demonstrated that all genera except Shewanella were psychrophiles with optimal growth below 15°C, and adaptation to low temperature was demonstrated as a shift from primarily C16:0 saturated fatty acids to C16:1 monounsaturated fatty acids at lower temperatures. This study provides the first targeted enrichment and characterization of psychrophilic denitrifying bacteria from polar sediments, and two genera, Arcobacter and Herminiimonas, are isolated for the first time from permanently cold marine sediments.
Application of Random Match Probability Calculations to Mixed STR Profiles
Authors: Bille Todd , Bright Jo‐Anne , Buckleton John 
Published: February 2013

AbstractMixed DNA profiles are being encountered more frequently as laboratories analyze increasing amounts of touch evidence. If it is determined that an individual could be a possible contributor to the mixture, it is necessary to perform a statistical analysis to allow an assignment of weight to the evidence. Currently, the combined probability of inclusion (CPI) and the likelihood ratio (LR) are the most commonly used methods to perform the statistical analysis. A third method, random match probability (RMP), is available. This article compares the advantages and disadvantages of the CPI and LR methods to the RMP method. We demonstrate that although the LR method is still considered the most powerful of the binary methods, the RMP and LR methods make similar use of the observed data such as peak height, assumed number of contributors, and known contributors where the CPI calculation tends to waste information and be less informative.