bluuebunny/crossref_metadata_2025 huggingface dataset:
Potential dust emissions from the southern Kalahari's dunelands
Authors: Bhattachan Abinash , D'Odorico Paolo , Okin Gregory S. , Dintwe Kebonyethata
Published: February 2013

The Southern Hemisphere shows relatively low levels of atmospheric dust concentrations. Dust concentrations could, however, increase as a result of losses of vegetation cover in the southern Kalahari. There is some evidence of an ongoing remobilization of stabilized dunefields in the southern Kalahari where dune crests with sparse vegetation cover are reactivated during dry and windy periods, a phenomenon that is predicted to intensify with increased land degradation, overgrazing, and droughts. Despite the potentially important climatic and biogeochemical implications of dust emissions from the Kalahari, it is still unclear whether the predicted remobilization of the Kalahari dunes could be associated with increased dust emissions from this region. The dependence of sediment fluxes and dust emissions on vegetation cover in the Kalahari dunelands remains poorly understood, which prevents a quantitative assessment of possible changes in aeolian activity in this region under different land use and land cover scenarios. In this study, we report the results of an aeolian sediment sampling campaign over a variety of land covers in the southern Kalahari. We use these results to quantify the potential rate of dust emissions and its dependence on vegetation cover and to make an estimate of dust fluxes from a portion of the southern Kalahari. The results show that the loss of vegetation could lead to substantial increases in dust emission and nutrient loss.
Emissions of carbon dioxide and methane from a headwater stream network of interior Alaska
Authors: Crawford John T. , Striegl Robert G. , Wickland Kimberly P. , Dornblaser Mark M. , Stanley Emily H.
Published: February 2013

Boreal ecosystems store significant quantities of organic carbon (C) that may be vulnerable to degradation as a result of a warming climate. Despite their limited coverage on the landscape, streams play a significant role in the processing, gaseous emission, and downstream export of C, and small streams are thought to be particularly important because of their close connection with the surrounding landscape. However, ecosystem carbon studies do not commonly incorporate the role of the aquatic conduit. We measured carbon dioxide (CO2) and methane (CH4) concentrations and emissions in a headwater stream network of interior Alaska underlain by permafrost to assess the potential role of stream gas emissions in the regional carbon balance. First‐order streams exhibited the greatest variability in fluxes of CO2 and CH4, and the greatest mean pCO2. High‐resolution time series of stream pCO2 and discharge at two locations on one first‐order stream showed opposing pCO2 responses to storm events, indicating the importance of hydrologic flowpaths connecting CO2‐rich soils with surface waters. Repeated longitudinal surveys on the stream showed consistent areas of elevated pCO2 and pCH4, indicative of discrete hydrologic flowpaths delivering soil water and groundwater having varying chemistry. Up‐scaled basin estimates of stream gas emissions suggest that streams may contribute significantly to catchment‐wide CH4 emissions. Overall, our results indicate that while stream‐specific gas emission rates are disproportionately high relative to the terrestrial landscape, both stream surface area and catchment normalized emission rates were lower than those documented for the Yukon River Basin as a whole. This may be due to limitations of C sources and/or C transport to surface waters.
Contamination rates between smart cell phones and non‐smart cell phones of healthcare workers
Authors: Lee Yeon Joo , Yoo Chul‐Gyu , Lee Choon‐Taek , Chung Hee Soon , Kim Young Whan , Han Sung Koo , Yim Jae‐Joon
Published: February 2013

BACKGROUND

Healthcare workers' mobile phones are easily contaminated with pathogenic bacteria and could be vehicles of transmission. Smart phones are increasingly used in the hospital. The objective of this study was to compare the contamination rate of bacteria with pathogenic potential between smart phones and non‐smart phones.

METHODS

We screened mobile phones of healthcare workers in three teaching hospitals in South Korea. The identification of cultivated micro‐organisms and assessment of antibiotic susceptibility were performed.

RESULTS

One hundred fifteen (56.7%) participants used smart phones, and 88 (43.3%) used non‐smart phones. Bacteria with pathogenic potential were isolated from 58 (28.6%) mobile phones, more often from smart phones than from non‐smart phones (34.8% vs 20.5%, P=0.03). Multivariate analysis including various characteristics to determine risk factors revealed that only smart phones (vs non‐smart phones) were a significant risk factor for contamination by bacteria with pathogenic potential (adjusted odds ratio [OR], 4.02; 95% confidence interval [CI], 1.43‐11.31). Also, in a multivariate model including phone size, the smart phone was still a significant risk factor for the pathogen contamination (OR, 4.17; 95% CI, 1.07‐16.33; P=0.04).

CONCLUSION

The smart phones of healthcare workers were contaminated with bacteria with pathogenic potential to a greater extent than were non‐smart phones. Journal of Hospital Medicine 2013;8:144–147. © 2013 Society of Hospital Medicine
Quantitative effects of inclusion of fat on muscle diffusion tensor MRI measurements
Authors: Williams Sarah E. , Heemskerk Anneriet M. , Welch E. Brian , Li Ke , Damon Bruce M. , Park Jane H.
Published: February 2013

Purpose

To determine the minimum water percentage in a muscle region of interest that would allow diffusion tensor (DT−) MRI data to reflect the diffusion properties of pure muscle accurately.

Materials and Methods

Proton density‐weighted images with and without fat saturation were obtained at the mid‐thigh in four subjects. Co‐registered DT‐MR images were used to calculate the diffusion tensor's eigenvalues and fractional anisotropy.

Results

The eigenvalues transitioned monotonically as a function of water signal percentage from values near to those expected for pure fat to those for pure muscle. Also, the fractional anisotropy transitioned monotonically from 0.50 (fat) to 0.20 (muscle). For water signal percentages >55%, none of the diffusion indices differed significantly from those for regions of >90% muscle.

Conclusion

Accounting for the T1 and T2 values of muscle and fat and the pulse sequence properties, it is concluded that, as a conservative estimate, regions must contain at least 76% muscle tissue to reflect the diffusion properties of pure muscle accurately. J. Magn. Reson. Imaging 2013;38:1292–1297. © 2013 Wiley Periodicals, Inc.
Magnetic resonance voiding cystourethrography (MRVCUG): A potential alternative to standard VCUG
Authors: Johnin Kazuyoshi , Takazakura Ryutaro , Furukawa Akira , Okamoto Keisei , Murakami Yoshitaka , Murata Kiyoshi , Okada Yusaku
Published: February 2013

Purpose

To evaluate the accuracy and feasibility of magnetic resonance voiding cystourethrography (MRVCUG), with or without contrast medium, in detecting vesicoureteral reflux (VUR) by comparison with conventional voiding cystourethrography (VCUG).

Materials and Methods

Seventy‐five patients underwent a series of 55 indirect MRVCUG (I‐MRVCUG) and 61 direct MRVCUG (D‐MRVCUG) between 2003 and 2009. We retrospectively compared the results from I‐MRVCUG and D‐MRVCUG with those from VCUG on 150 kidney‐ureter units. Ratios of successful completion of the two types of MRVCUG were analyzed in 116 examinations according to sex, age, and among the two groups, with or without sedation.

Results

D‐MRVCUG was superior to I‐MRVCUG in detecting VUR (sensitivity: 96.8% vs. 76.9%; specificity: 96.3% vs. 88.7%; agreement: 96.6% vs. 83.7%; kappa: 0.83 [95% confidence interval (CI): 0.72, 0.94] vs. 0.55 [95% CI: 0.41, 0.69]). The overall ratio of successful completion of the two types of MRVCUG was 76.7% (89/116): there was no significant difference between I‐MRVCUG and D‐MRVCUG. The successful completion rate was significantly lower in MRVCUG in toddlers compared with preschoolers, infants, schoolchildren, and adults (P < 0.001).

Conclusion

The two types of MRVCUG (I‐MRVCUG and D‐MRVCUG) are promising tests without radiation exposure. Both I‐MRVCUG and D‐MRVCUG are feasible for children except for toddlers. J. Magn. Reson. Imaging 2013;38:897–904. © 2013 Wiley Periodicals, Inc.
Single nucleotide polymorphisms rs2120131, rs4935047, and rs7095891 in the MBL2 gene show no association with susceptibility to chronic hepatitis B in a Chinese Han population
Authors: Zhang Tian‐Chen , Liu Wei , Liu Xiao‐Qing , Pan Fa‐Ming , Gao Yu‐Feng , Yan Fang , Li Xu
Published: February 2013

Thus far, many studies have evaluated the correlation between MBL2 gene polymorphisms and hepatitis B infection. Tag single nucleotide polymorphisms (SNPs) were used to investigate the relationship between MBL2 gene polymorphisms and susceptibility to chronic hepatitis B virus (HBV) infection by comparing 996 chronic HBV infection cases to 301 acute infection controls. There was no significant correlation between rs2120131, rs4935047, and rs7095891 and chronic HBV infection. This suggested that the new SNPs within MBL2 were not associated with susceptibility to chronic hepatitis B in a Chinese Han population. J. Med. Virol. 85:602–607, 2013. © 2013 Wiley Periodicals, Inc.
Intrafamilial transmission of hepatitis C virus
Authors: Indolfi Giuseppe , Nesi Alessandro , Resti Massimo
Published: February 2013

HCV infection is a major public health problem worldwide. Several studies reported that HCV infection might cluster in families or households. Horizontal intrafamilial transmission of the virus has been demonstrated previously. Whether horizontal transmission makes any significant contribution to the global burden of HCV infection is still controversial and data about epidemiology and routes of transmission are uncertain. The certain diagnosis of horizontal intrafamilial transmission of HCV is based on the simultaneous presence of specific laboratory criteria, the temporal association between intrafamilial exposure and infection and the exclusion of all the potential extrafamilial routes of transmission of the infection. This review summarizes the current knowledge of epidemiology, risk factors and molecular biology of horizontal intrafamilial transmission of HCV infection. J. Med. Virol. 85:608–614, 2013. © 2013 Wiley Periodicals, Inc.
Self‐organized criticality of cellular automata model; absorbtion in finite‐time of supercritical region into the critical one
Authors: Barbu Viorel
Published: February 2013

In this work, it is studied the evolution and time behavior of solutions to nonlinear diffusion equation in where , d ≥ 1, and H is the Heaviside function. For d = 1,2,3, this equation describes the dynamics of self‐organizing sandpile process with critical state ρc. The main conclusion is that the supercritical region is absorbed in a finite‐time in the critical region . Copyright © 2013 John Wiley & Sons, Ltd.
A constrained sub‐optimal controller for glucose regulation in type 1 diabetes mellitus
Authors: Ghosh Subhojit , Maka S.
Published: February 2013

Patients with type 1 diabetes mellitus require exogenous insulin infusion to avoid chronic complications related to elevated glucose levels. With diabetes reaching epidemic proportions, recent times have witnessed an increased attention in the field of optimal glucose management by closed‐loop insulin delivery system. A proper glucose management scheme, in addition of maintaining the glucose level within the normal range of 80–120 mg/dL, should avoid excessive insulin delivery leading to hypoglycemia. By considering the glucose regulation as a linear quadratic problem, a constrained novel sub‐optimal controller is proposed in the present work, for the maintenance of normal glucose level in type 1 diabetic subjects. The observer free state feedback controller is based on the feedback of only physiological variables (plasma glucose and plasma insulin). Constraining the feedback elements corresponding to the non‐physiological variables avoids the use of an observer while maintaining the advantages of state feedback control. The implementation of the proposed scheme requires simple measurement protocol with no online computation. The closed‐loop performance of the controller is evaluated on a physiologically relevant model for a meal disturbance and continuous glucose infusion. Copyright © 2013 John Wiley & Sons, Ltd.
Identifying suicidal behavior among adolescents using administrative claims data
Authors: Callahan S. Todd , Fuchs D. Catherine , Shelton Richard C. , Balmer Leanne S. , Dudley Judith A. , Gideon Patricia S. , DeRanieri Michelle M. , Stratton Shannon M. , Williams Candice L. , Ray Wayne A. , Cooper William O.
Published: February 2013

Purpose

To assess the safety of psychotropic medication use in children and adolescents, it is critical to be able to identify suicidal behaviors from medical claims data and distinguish them from other injuries. The purpose of this study was to develop an algorithm using administrative claims data to identify medically treated suicidal behavior in a cohort of children and adolescents.

Methods

The cohort included 80 183 youth (6–18 years) enrolled in Tennessee's Medicaid program from 1995–2006 who were prescribed antidepressants. Potential episodes of suicidal behavior were identified using external cause‐of‐injury codes (E‐codes) and ICD‐9‐CM codes corresponding to the potential mechanisms of or injuries resulting from suicidal behavior. For each identified episode, medical records were reviewed to determine if the injury was self‐inflicted and if intent to die was explicitly stated or could be inferred.

Results

Medical records were reviewed for 2676 episodes of potential self‐harm identified through claims data. Among 1162 episodes that were classified as suicidal behavior, 1117 (96%) had a claim for suicide and self‐inflicted injury, poisoning by drugs, or both. The positive predictive value of code groups to predict suicidal behavior ranged from 0–88% and improved when there was a concomitant hospitalization but with the limitation of excluding some episodes of confirmed suicidal behavior.

Conclusions

Nearly all episodes of confirmed suicidal behavior in this cohort of youth included an ICD‐9‐CM code for suicide or poisoning by drugs. An algorithm combining these ICD‐9‐CM codes and hospital stay greatly improved the positive predictive value for identifying medically treated suicidal behavior. Copyright © 2013 John Wiley & Sons, Ltd.
Evaluation of the influence of an embedded porous silicon layer on the bulk lifetime of epitaxial layers and the interface recombination at the epitaxial layer/porous silicon interface
Authors: Radhakrishnan Hariharsudan Sivaramakrishnan , Dross Frederic , Debucquoy Maarten , Rosenits Philipp , Van Nieuwenhuysen Kris , Gordon Ivan , Poortmans Jef , Mertens Robert
Published: February 2013

Porous silicon plays an important role in the concept of wafer‐equivalent epitaxial thin‐film solar cells. Although porous silicon is beneficial in terms of long‐wavelength optical confinement and gettering of metals, it could adversely affect the quality of the epitaxial silicon layer grown on top of it by introducing additional crystal defects such as stacking faults and dislocations. Furthermore, the epitaxial layer/porous silicon interface is highly recombinative because it has a large internal surface area that is not accessible for passivation. In this work, photoluminescence is used to extract the bulk lifetime of boron‐doped (1016/cm3) epitaxial layers grown on reorganised porous silicon as well as on pristine mono‐crystalline, Czochralski, p+ silicon. Surprisingly, the bulk lifetime of epitaxial layers on top of reorganised porous silicon is found to be higher (~100–115 µs) than that of layers on top of bare p+ substrate (32–50 µs). It is believed that proper surface closure prior to epitaxial growth and metal gettering effects of porous silicon play a role in ensuring a higher lifetime. Furthermore, the epitaxial layer/porous silicon interface was found to be ~250 times more recombinative than an epitaxial layer/p+ substrate interface (S ≅ 103 cm/s). However, the inclusion of an epitaxially grown back surface field on top of the porous silicon effectively shields minority carriers from this highly recombinative interface. Copyright © 2013 John Wiley & Sons, Ltd.
Extracting iron and manganese from bacteria with ionophores—A mechanism against competitors characterized by increased potency in environments low in micronutrients
Authors: Raatschen Nadja , Wenzel Michaela , Ole Leichert Lars Ingo , Düchting Petra , Krämer Ute , Elisabeth Bandow Julia
Published: February 2013

To maintain their metal ion homeostasis, bacteria critically depend on membrane integrity and controlled ion translocation. Terrestrial Streptomyces species undermine the function of the cytoplasmic membrane as diffusion barrier for metal cations in competitors using ionophores. Although the properties of the divalent cation ionophores calcimycin and ionomycin have been characterized to some extent in vitro, their effects on bacterial ion homeostasis, the factors leading to bacterial cell death, and their ecological role are poorly understood. To gain insight into their antibacterial mechanism, we determined the metal ion composition of the soil bacterium Bacillus subtilis after treatment with calcimycin and ionomycin. Within 15 min the cells lost approximately half of their cellular iron and manganese content whereas calcium levels increased. The proteomic response of B. subtilis provided evidence that disturbance of metal cation homeostasis is accompanied by intracellular oxidative stress, which was confirmed with a ROS‐specific fluorescent probe. B. subtilis showed enhanced sensitivity to the ionophores in medium lacking iron or manganese. Furthermore, in the presence of ionophores bacteria were sensitive to high calcium levels. These findings suggest that divalent cation ionophores are particularly effective against competing microorganisms in soils rich in available calcium and low in available iron and manganese.
Increased rubber content in high impact polypropylene via a sirius ziegler‐natta catalyst containing nanoparticles
Authors: Vestberg Torvald , Denifl Peter , Wilén Carl‐Eric
Published: February 2013

High impact polypropylene was produced in a two‐reactor polymerization process operating in series using two different Ziegler‐Natta catalysts (referred to as catalysts A and B) that had been prepared by Sirius emulsion technology in the absence and presence of SiO2 nanoparticles, respectively. The homo polypropylene matrix was produced in liquid bulk and the ethylene/propylene rubber in gas phase under industrial conditions. Catalyst B was prepared with the same emulsion technology as catalyst A, except that SiO2 nanoparticles (average particles size 80 nm) were added during catalyst preparation. Scanning electron microscopy studies showed that the nanoparticles were fairly evenly distributed within catalyst B particles, although there was some agglomeration. It was shown that the nanoparticles in catalyst B increased the internal porosity in the homo polypropylene matrix particles and this enabled a significant increase in the rubber content. Maximum rubber content, before running into stickiness problems, was approximately 25 wt % for catalyst A without nanoparticles, whereas the maximum rubber content for catalyst B was almost doubled to 45 wt % due to the beneficial transformation of the internal catalyst morphology by the nanoparticles. In addition, it was also found that the reaction was not mass transfer limited during the ethylene/propylene rubber polymerization stage, even at very high rubber contents where all pores and cavities were filled with rubber. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013
Organic–inorganic hybrid diblock copolymer composed of poly (ε‐caprolactone) and poly(MA POSS): Synthesis and its nanocomposites with epoxy resin
Authors: Wang Lei , Li Jingang , Li Lei , Zheng Sixun
Published: February 2013

Organic–inorganic hybrid diblock copolymers composed of poly(ε‐caprolactone) and poly(MA POSS) [PCL‐b‐P(MA POSS)] were synthesized via reversible addition‐fragmentation chain transfer polymerization of 3‐methacryloxypropylheptaphenyl polyhedral oligomeric silsesquioxane (MA POSS) with dithiobenzoate‐terminated poly(ε‐caprolactone) as the macromolecular chain transfer agent. The dithiobenzoate‐terminated poly(ε‐caprolactone) (PCL‐CTA) was synthesized via the atom transfer radical reaction of 2‐bromopropionyl‐terminated PCL with bis(thiobenzoyl)disulfide in the presence of the complex of copper (I) bromide with N,N,N′,N″,N″‐pentamethyldiethylenetriamine. The results of molecular weights and polydispersity indicate that the polymerizations were in a controlled fashion. The organic–inorganic diblock copolymer was incorporated into epoxy to afford the organic–inorganic nanocomposites. The nanostructures of the organic–inorganic composites were investigated by means of transmission electron microscopy and dynamic mechanical thermal analysis. Thermogravimetric analysis shows that the organic–inorganic nanocomposites displayed the increased yields of degradation residues compared to the control epoxy. In the organic–inorganic nanocomposites, the inorganic block [viz., P(MA POSS)] had a tendency to enrich at the surface of the materials and the dewettability of surface for the organic–inorganic nanocomposites were improved in terms of the measurement of surface contact angles. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013
Role of bias conditions in the hot carrier degradation of AlGaN/GaN high electron mobility transistors
Authors: Mukherjee Shubhajit , Puzyrev Yevgeny , Hinckley John , Schrimpf Ronald D. , Fleetwood Daniel M. , Singh Jasprit , Pantelides Sokrates T.
Published: February 2013

The impacts of gate bias and device temperature on carrier energy distributions are reported for AlGaN/GaN High Electron Mobility Transistors. The lateral electric field and the average carrier energy are the highest at the end of gate on the gate‐drain access side. The number of high energy carriers is the greatest in the semi‐ON operating condition, with maximum energies exceeding the activation energy of defects in the AlGaN. There is a significant decrease in the number of very high energy carriers (greater than 2 eV) as the device temperature increases whereas the number of moderately energetic carriers (between 1 to 2 eV) is higher at elevated temperatures.(© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ab initio chemical kinetics for reactions of H atoms with SiHx (x = 1–3) radicals and related unimolecular decomposition processes
Authors: Raghunath Putikam , Lee Yun‐Min , Wu Shang‐Ying , Wu Jong‐Shinn , Lin Ming‐Chang
Published: February 2013

Hydrogen atoms and SiHx (x = 1–3) radicals coexist during the chemical vapor deposition (CVD) of hydrogenated amorphous silicon (a‐Si:H) thin films for Si‐solar cell fabrication, a technology necessitated recently by the need for energy and material conservation. The kinetics and mechanisms for H‐atom reactions with SiHx radicals and the thermal decomposition of their intermediates have been investigated by using a high high‐level ab initio molecular‐orbital CCSD (Coupled Cluster with Single and Double)(T)/CBS (complete basis set extrapolation) method. These reactions occurring primarily by association producing excited intermediates, 1SiH2, 3SiH2, SiH3, and SiH4, with no intrinsic barriers were computed to have 75.6, 55.0, 68.5, and 90.2 kcal/mol association energies for x = 1–3, respectively, based on the computed heats of formation of these radicals. The excited intermediates can further fragment by H2 elimination with 62.5, 44.3, 47.5, and 56.7 kcal/mol barriers giving 1Si, 3Si, SiH, and 1SiH2 from the above respective intermediates. The predicted heats of reaction and enthalpies of formation of the radicals at 0 K, including the latter evaluated by the isodesmic reactions, SiHx + CH4 = SiH4 + CHx, are in good agreement with available experimental data within reported errors. Furthermore, the rate constants for the forward and unimolecular reactions have been predicted with tunneling corrections using transition state theory (for direct abstraction) and variational Rice–Ramsperger–Kassel–Marcus theory (for association/decomposition) by solving the master equation covering the P,T‐conditions commonly employed used in industrial CVD processes. The predicted results compare well experimental and/or computational data available in the literature. © 2013 Wiley Periodicals, Inc.
Spectral characterization of ten cyclic lipids using time‐of‐flight secondary ion mass spectrometry
Authors: Leefmann Tim , Heim Christine , Siljeström Sandra , Blumenberg Martin , Sjövall Peter , Thiel Volker
Published: February 2013

RATIONALE

Over the last decade, the high lateral resolution and imaging capabilities of time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) have increasingly stimulated interest in studying organic molecules in complex environmental materials. However, unlike with the established mass spectrometric techniques, the use of ToF‐SIMS in the biogeosciences is still hampered by a lack of reference spectra of the relevant biomarker compounds. Here we present and interpret ToF‐SIMS reference spectra of ten different cyclic lipids that are frequently used as biological tracers in ecological, organic geochemical and geobiological studies.

METHODS

Standard compounds of α,β,β‐(20R,24S)‐24‐methylcholestane, (22E)‐ergosta‐5,7,22‐trien‐3β‐ol, 17α(H),21β‐(H)‐30‐norhopane, hope‐17(21)‐ene, hop‐22(29)‐ene, 17β(H),21β(H)‐bacteriohopane‐32,33,34,35‐tetrol, 17β(H),21β(H)‐35‐aminobacteriohopane‐32,33,34‐triol, α‐tocopherol, β,β‐carotene, chlorophyll a, and cryosections of microbial mats and a fungus were analyzed using a ToF‐SIMS instrument equipped with a Bi3+ cluster ion source.

RESULTS

The spectra obtained from the standard compounds showed peaks in the molecular weight range (molecular ions, protonated and deprotonated molecules, adduct ions) and diagnostic fragment ion peaks in both, positive and negative ion modes. For the cyclic hydrocarbons, however, the positive ion mode spectra typically showed more and stronger characteristic peaks than the negative ion mode spectra. Using real world samples the capability of ToF‐SIMS to detect and image selected compounds in complex organic matrices was tested. 17β(H),21β(H)‐35‐Aminobacteriohopane‐32,33,34‐triol, carotene and chlorophyll a were successfully identified in cryosections of microbial mats, and the distribution of ergosterol was mapped at µm resolution in a cryosection of a fungus (Tuber uncinatum).

CONCLUSIONS

This study further highlights the utility of ToF‐SIMS for the identification and localization of lipids within environmental samples and as a technique for biomarker‐related research in organic geochemistry and geobiology. Copyright © 2013 John Wiley & Sons, Ltd.
Measurement of SLAP2 and GISP δ17O and proposed VSMOW‐SLAP normalization for δ17O and 17Oexcess
Authors: Schoenemann Spruce W. , Schauer Andrew J. , Steig Eric J.
Published: February 2013

RATIONALE

The absence of an agreed‐upon δ17O value for the primary reference water SLAP leads to significant discrepancies in the reported values of δ17O and the parameter 17Oexcess. The accuracy of δ17O and 17Oexcess values is significantly improved if the measurements are normalized using a two‐point calibration, following the convention for δ2H and δ18O values.

METHODS

New measurements of the δ17O values of SLAP2 and GISP are presented and compared with published data. Water samples were fluorinated with CoF3. Helium carried the O2 product to a 5A (4.2 to 4.4 Å) molecular sieve trap submerged in liquid nitrogen. The O2 sample was introduced into a dual‐inlet ThermoFinnigan MAT 253 isotope ratio mass spectrometer for measurement of m/z 32, 33, and 34. The δ18O and δ17O values were calculated after 90 comparisons with an O2 reference gas.

RESULTS

We propose that the accepted δ17O value of SLAP be defined in terms of δ18O = −55.5 ‰ and 17Oexcess = 0, yielding a δ17O value of approximately −29.6968 ‰. Using this definition for SLAP and the recommended normalization procedure, the δ17O value of GISP is −13.16 ± 0.05 ‰ and the 17Oexcess value of GISP is 22 ± 11 per meg. Correcting previous published values of GISP δ17O to both VSMOW and SLAP improves the inter‐laboratory precision by about 10 per meg.

CONCLUSIONS

The data generated here and compiled from previous studies provide a substantial volume of evidence to evaluate the various normalization techniques currently used for triple oxygen isotope measurements. We recommend that reported δ17O and 17Oexcess values be normalized to the VSMOW‐SLAP scale, using a definition of SLAP such that its 17Oexcess is exactly zero. Copyright © 2013 John Wiley & Sons, Ltd.
Discovery of gymnodimine fatty acid ester metabolites in shellfish using liquid chromatography/mass spectrometry
Authors: de la Iglesia P. , McCarron P. , Diogène J. , Quilliam M. A.
Published: February 2013

RATIONALE

Gymnodimines (GYMs) are fast‐acting toxins that belong to the cyclic imine group, a subclass of lipophilic marine toxins. GYMs are considered to be emerging toxins but have not yet been linked to incidents of human poisoning, Limited knowledge on the metabolism of GYMs means that a proper risk assessment has not been possible and caution must be taken when establishing the relevance of GYMs in terms of food safety of marine products.

METHODS

A series of mass spectrometric experiments involving precursor and product ion scans, selected reaction monitoring (SRM), and high‐resolution mass spectrometry (MS) were used to detect and confirm 10‐O‐acyl esters of gymnodimine‐A (1).

RESULTS

We have detected for the first time the presence of a range of acyl ester derivatives of GYMs in shellfish samples from the Gulf of Gabes, Tunisia. The MS fragmentation pathways of 1 and its esters were also elucidated. Partial synthesis of a palmitic acid ester of 1 facilitated confirmation of identity and calibration of SRM analyses. Evidence of acyl ester metabolites of gymnodimine‐B and ‐C was also obtained.

CONCLUSIONS

A semi‐quantitative analysis indicated that the majority of GYMs present in the sample were in the acylated form (>90%), suggesting that these compounds must not be neglected when trying to understand the risks associated with GYMs. There is a clear need for toxicology studies on these esters and assessment of bio‐availability to humans. Copyright © 2013 Crown in the right of Canada and John Wiley & Sons, Ltd.
A post‐quantum provable data possession protocol in cloud
Authors: Chen Liang , Han Lansheng , Jing Jiandu , Hu Dongping
Published: February 2013

Provable data possession (PDP) is a model for efficiently checking the integrity of data in cloud storage. Most previous PDP protocols are insecure when quantum computers are considered. In this paper, we propose a homomorphic hash‐based PDP (HH‐PDP) protocol from ideal lattice assumptions. Firstly, we prove that a collision‐resistant hash function family is homomorphic. Then, we use the homomorphism to generate homomorphic verification tags and further construct a new PDP protocol. The security of the proposed protocol relies on the assumed worst‐case hardness of ideal lattice problems, which hold a great promise for post‐quantum cryptography. We prove that the proposed protocol guarantees data possession in the standard model if the shortest polynomial problem is hard. As the main operations in our construction are addition and multiplication on small integers, the proposed protocol is more efficient than previous protocols. Experimental result shows that HH‐PDP is approximately five times cheaper in preprocessing and checking proof, half cost in generating proof compared with the most efficient PDP protocol proposed by Ateniese et al. in 2011. Copyright © 2013 John Wiley & Sons, Ltd.
A study of privacy problem solving using device and user authentication for M2M environments
Authors: Kim Jin‐Mook , Jeong Hwa‐Young , Hong Bong‐Hwa
Published: February 2013

Inside a machine‐to‐machine (M2M) environment, a device is very much a communication subject. Machine and gateways are important communication subjects. It can be collecting or storing surrounding information as user's intention. There is a case that infringes other person's privacy such as not passing through a certification process of the user or communication chairman who requests communications among the information that is collected by the machine. Therefore, we wish to propose privacy problem solving using device and user authentication (PSDUA) that can support the certification process between device and user communicating the subject in M2M environment and can support the user in another certification work about various services. PSDUA proposes a design that can pass through a light certification process based on existent system. For example, Kerberos and public key infrastructure (PKI) can support very heavy certification process but our proposed scheme cannot. However, our proposed system can act easily and fast and that gradual access may be possible using time stamp, device identification, and user log‐in information. It can also protect privacy information of other person or machines that are not the subject of communication. Additionally, we also check about confidentiality, integrity, and safety of machine‐in‐the‐middle attack. Also, we can show safety in our proposed system. Our proposed scheme will provide solutions on various securities privacy problems. Copyright © 2013 John Wiley & Sons, Ltd.
Isothermal Hybridization Kinetics of DNA Assembly of Two‐Dimensional DNA Origami
Authors: Song Jie , Zhang Zhao , Zhang Shuai , Liu Lei , Li Qiang , Xie Erqing , Gothelf Kurt Vesterager , Besenbacher Flemming , Dong Mingdong
Published: February 2013

The Watson–Crick base‐pairing with specificity and predictability makes DNA molecules suitable for building versatile nanoscale structures and devices, and the DNA origami method enables researchers to incorporate more complexities into DNA‐based devices. Thermally controlled atomic force microscopy in combination with nanomechanical spectroscopy with forces controlled in the pico Newton (pN) range as a novel technique is introduced to directly investigate the kinetics of multistrand DNA hybridization events on DNA origami nanopores under defined isothermal conditions. For the synthesis of DNA nanostructures under isothermal conditions at 60 °C, a higher hybridization rate, fewer defects, and a higher stability are achieved compared to room‐temperature studies. By quantifying the assembly times for filling pores in origami structures at several constant temperatures, the fill factors show a consistent exponential increase over time. Furthermore, the local hybridization rate can be accelerated by adding a higher concentration of the staples. The new insight gained on the kinetics of staple‐scaffold hybridization on the synthesis of two dimensional DNA origami structures may open up new routes and ideas for designing DNA assembly systems with increased potential for their application.
Evidence for Plio‐Pleistocene north‐south extension at the southern margin of the Tibetan Plateau, Nyalam region
Authors: McDermott Jeni A. , Whipple Kelin X. , Hodges Kip V. , van Soest Matthijs C.
Published: February 2013

The southern Tibetan Plateau margin between ~ 83°E and 86.5°E is defined by an abrupt change from the low‐relief Tibetan Plateau to the rugged topography and deep gorges of the Himalaya. This physiographic transition lies well to the north of active thrusting, and thus, the mechanism responsible for the distinct topographic break remains the focus of much debate. While numerous studies have utilized thermochronology to examine the exhumation history of the Himalaya, few have done so with respect to variations across the Himalaya‐Tibetan Plateau transition. In this work, we examine the nature of the transition where it is accessible and well‐defined in the Nyalam valley of south‐central Tibet. We employ several new and previously published thermochronologic datasets (with a closure temperature range of ~ 70°C–300°C) in conjunction with river incision patterns inferred by the longitudinal profile of the Bhote Kosi River. The results reveal a sharp change in cooling rate at ~ 3.5 Ma at a location corresponding to a pronounced river knickpoint representing a sharp increase in river gradient and presumably incision rate (a proxy for rock uplift). Margin retreat models for the physiographic transition are inconsistent with the cooling pattern revealed by low‐temperature thermochronologic data. Models invoking passive uplift of the upper crust over a midcrustal ramp and associated duplex to account for the physiographic transition do not explain the observed break in cooling rate there, although they may explain a suggesting in the thermochronologic data of progressively increasing exhumation rates south of the transition. The simplest model consistent with all observations is that passive uplift is augmented by contemporaneous differential uplift across a young (Pliocene‐Quaternary) normal fault at the physiographic transition. Drawing on observations elsewhere, we hypothesize that similar structural relationships may be characteristic of the Tibetan Plateau‐Himalaya transition from ~83°E – 86.5°E.
Transpressive inversion of a Mesozoic extensional forced fold system with an intermediate décollement level in the Basque‐Cantabrian Basin (Spain)
Authors: Tavani Stefano , Carola Eloi , Granado Pablo , Quintà Anna , Muñoz Josep Anton
Published: February 2013

In the Basque‐Cantabrian Basin (Spain), normal faulting and associated folding occurred during Late Jurassic to Early Cretaceous rifting. Cenozoic Pyrenean thick‐skinned transpressive inversion in the western parts of the basin preserved the first‐order extensional architecture. Integration of geological maps and seismic profiles has permitted to fully constrain the style of extensional deformation and subsequent inversion in the western portion of the Basque‐Cantabrian Basin. Extensional faults offset the Paleozoic basement up to Lower Triassic rocks. The presence of an efficient décollement level represented by Triassic evaporites produced the decoupling between basement rocks and the Upper Triassic to Middle Jurassic prerift cover sequence. Extensional forced folding occurred in the cover, driven by basement faulting and the migration of evaporites toward the hanging wall of the extensional faults, with salt welds developing away from them. Upper Jurassic to Lower Cretaceous syn‐rift sediments deposited synchronously with forced folding, which led to the development of extensional growth geometries associated with both master faults and nearly‐transverse faults. Syn‐rift growth sequences are characterized by downlap and onlap relationships with the underlying prerift units, interpreted as the result of along‐strike variations of master fault extensional displacement rate. Cenozoic Pyrenean contraction generated the right‐lateral transpressive inversion of basement master faults and the almost dip‐slip reactivation of transverse extensional faults.
The chemical characterization and tectonic significance of ophiolite terrains in southeastern Papua New Guinea
Authors: Smith Ian E. M.
Published: February 2013

The evolution of the southeastern Gondwana margin in the Papua New Guinea segment is manifested by ophiolites signifying plate collision, volcanic arcs marking subduction, and metamorphic core complexes that have developed during extensional events and exhumation associated with sea floor spreading in the Woodlark Basin to the east. In detail the Papuan Ultramafic Belt marks a well‐documented collision between continental crust and a subduction system. However, to the southeast, an extensive sequence of basaltic rocks known as the Milne Terrain is more problematic. Geochemical data indicate that these upper Cretaceous and Eocene rocks have MORB‐type affinities, and their most likely tectonic association is with the opening of the Coral Sea Basin. Milne Terrain rocks represent the lower plate in the obduction system along which the Papuan Ultramafic Belt was emplaced, and thus they are the structural equivalent of the continental crust which was separated from the Australian continental block by the opening of the Coral Sea. Spectacular uplift (>4 km) of the oceanic basaltic crust of the Milne Terrain may be due to the underlying presence of underplated material associated with a Late Miocene‐Pliocene episode of subduction immediately prior to the encroachment of the Woodlark spreading center into the Papuan area.
Structural and anisotropy of magnetic susceptibility records of granitoid sheets emplacement during growth of a continental gneiss dome (Central Sudetes, European Variscan Belt)
Authors: Lehmann Jérémie , Schulmann Karel , Edel Jean–Bernard , Ježek Josef , Hrouda František , Lexa Ondrej , Chopin Francis
Published: February 2013

Granitoid magmatic sheets emplaced syntectonically during growth of the Orlica‐Śnieżnik mantled gneiss dome (Central Sudetes, European Variscan belt) were examined by means of structural geology, quartz, and anisotropy of magnetic susceptibility (AMS) fabric studies. Magmatic emplacement was localized along the eastern transpressive margin of the high metamorphic core and below the low‐grade detached mantle rimming the southern margin of the dome. In the first area, the magmatic sheets were emplaced parallel to the dilated subhorizontal foliation of an anisotropic pre‐orogenic block. The resulting melt‐host rock multilayer localized the transpressive zone along which the bulk of magma was emplaced. The AMS study shows an across‐strike fabric zonation underlying a strongly transpressive solid‐state deformation in the hanging‐wall, magmatic subhorizontal fabric in the foot‐wall and a transitional fabric in the center of the intrusion. In contrast, along the southern dome margin, magmatic sheets intruded along steep foliations of weakly metamorphic mantle rocks, and are affected by recumbent folding and subhorizontal shearing. The bulk of the sheets present a shallow‐dipping magmatic foliation and an along‐strike magmatic lineation. The variations of the quartz and magnetic fabrics are attributed to superimposition of pure shear‐dominated ductile thinning followed by simple shear‐dominated detachment onto the original steep fabric. AMS modeling confirms the role of variation of orientation of pre‐intrusive anisotropy during progressive deformation on the resulting fabric pattern and helps explaining observed variations in fabric orientations and symmetries. This study highlights contrasting mechanical behavior of syntectonically emplaced magmas in different parts of a growing crustal‐scale mantled gneiss dome.
China's National Champions: The Evolution of a National Industrial Policy—Or a New Era of Economic Protectionism?
Authors: Hemphill Thomas A. , White George O.
Published: February 2013

In this article we ask a series of related research questions concerning China's recent industrial policies, particularly the 10th and 11th five‐year economic policy plans. Our questions go to the nature of China's long‐term competitiveness of its national champions, and to what extent Chinese government policies are evolving to domestic protectionism that adversely affects foreign invested enterprises' (FIEs) competitive position in the Chinese economy. We thus evaluate the nature of the five‐year economic policy plans, their adverse impact on FIEs operating in China, and the rise of designated Chinese national champions (in the 11th five‐year economic policy plan) to compete with major FIEs on a global scale. However, we suggest that the role of the Chinese government's recent industrial policy, when compared to Michael Porter's “Diamond of National Competitive Advantage” recommended government policy approaches, may not augur well in the long‐term for China's national champions. © 2013 Wiley Periodicals, Inc.
Value of adding second‐trimester uterine artery Doppler to patient characteristics in identification of nulliparous women at increased risk for pre‐eclampsia: an individual patient data meta‐analysis
Authors: Kleinrouweler C. E. , Bossuyt P. M. M. , Thilaganathan B. , Vollebregt K. C. , Arenas Ramírez J. , Ohkuchi A. , Deurloo K. L. , Macleod M. , Diab A. E. , Wolf H. , van der Post J. A. M. , Mol B. W. J. , Pajkrt E.
Published: February 2013

Objective

To investigate the value of adding second‐trimester uterine artery Doppler ultrasound to patient characteristics in the identification of nulliparous women at risk for pre‐eclampsia.

Methods

For this individual patient data meta‐analysis, studies published between January 1995 and December 2009 were identified in MEDLINE and EMBASE. Studies were eligible in which Doppler assessment of the uterine arteries had been performed among pregnant women and in which gestational age at ultrasound, Doppler ultrasound findings and data on the occurrence of pre‐eclampsia were available. We invited corresponding authors to share their original datasets. Data were included of nulliparous women who had had a second‐trimester uterine artery Doppler ultrasound examination. Shared data were checked for consistency, recoded to acquire uniformity and merged into a single dataset. We constructed random intercept logistic regression models for each of the patient and Doppler characteristics in isolation and for combinations. We compared goodness of fit, discrimination and calibration.

Results

We analyzed eight datasets, reporting on 6708 nulliparous women, of whom 302 (4.5%) developed pre‐eclampsia. Doppler findings included higher, lower and mean pulsatility index (PI) and resistance index (RI) and any or bilateral notching. Of these, the best predictors were combinations of mean PI or RI and bilateral notching, with areas under the receiver–operating characteristics curve (AUC) of 0.75 (95% confidence interval (CI), 0.56–0.95) and 0.70 (95% CI, 0.66–0.74), respectively. Addition of Doppler findings to the patient characteristics blood pressure or body mass index (BMI) significantly improved discrimination. A model with blood pressure, PI and bilateral notching had an AUC of 0.85 (95% CI, 0.67–1.00).

Conclusions

The addition of Doppler characteristics of mean PI or RI and bilateral notching to patient characteristics of blood pressure or BMI improves the identification of nulliparous women at risk for pre‐eclampsia. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd.
Parameter and predictive outcomes of model simplification
Authors: Watson Ty A. , Doherty John E. , Christensen Steen
Published: February 2013

Simplification is an unavoidable aspect of model usage. Even complex, physically based models are simplifications of reality. More profound simplification is required to construct the “lumped parameter” models of semiphysical basis that are often employed for simulation of large‐scale processes operative over one or many watersheds. Simplification can lead to model predictive error beyond that which would be expected on the basis of study‐area information deficits alone. Building on a recently developed mathematical description of the model simplification process, this work employs linear subspace methods to analyze in detail the nature and ramifications of that process when applied to a 1‐D, Richards equation‐based unsaturated zone model used to predict recharge to a groundwater system. Two simplified versions of this model are examined. The first achieves simplification through assuming vertical parameter uniformity. The second achieves simplification through use of a lumped parameter model in place of the Richards equation‐based model. Relationships between parameters employed by the complex model and those used by each of the simplified models are analyzed. The nature of predictive errors incurred through simplification is explored. Also explored is the ability of the calibration process to decrease the propensity for model error in making some predictions, while increasing the propensity for model error in the making of others (an outcome that may be considered counterintuitive from a Bayesian perspective, but which is a natural consequence of suboptimal simplification).