bluuebunny/crossref_metadata_2025 huggingface dataset:
An analysis of China's grain production: looking back and looking forward
Authors: Li Yuxuan , Zhang Weifeng , Ma Lin , Wu Liang , Shen Jianbo , Davies William J. , Oenema Oene , Zhang Fusuo , Dou Zhengxia
Published: December 2013

Ensuring food security is the foundation of economic development and social stability. China is historically a country that is dominated by agriculture. In the past 60 years, China's total grain output increased by fivefold, from 113 million tons (MT) in 1949 to 571 MT in 2011, a statistic which provides inspiration to producers in other parts of the world. Grain production per capita doubled, from 209 to 425 kg during the same time period. At the national scale, China has succeeded in maintaining a basic self‐sufficiency for grain for the past three decades. However, with the increasing population pressure and a growing appetite for animal products, China will need 776 MT grain by 2030 to feed its own people, a net increase of 35.9% from its best year on record. China's drive for future food security is challenged by problems such as low efficiency of resource use and resource limitation, diminishing return in yield response, competition for nonagricultural land uses, and environmental degradation. In this article, we analyze historical, temporal, and spatial variation in total grain production as well as the overall developing trends of current and future grain production, and discussed relevant options to overcome production constraints and further promote agricultural production.
Exceptional fidelity of preservation in a reworked fossil, Chalk drift, South London, England
Authors: Donovan Stephen K. , Fearnhead Fiona E.
Published: December 2013

Reworking of fossils commonly leads to loss of morphological detail and inferior preservation; the main contributions of such specimens to geology are in sedimentology, regional geology and neoichnology. A reworked specimen of the Late Cretaceous (chalk) sponge boring Entobia cretacea Portlock is unusually well preserved. This specimen is from superficial deposits and is well enough preserved that delicate apertural and intercameral canals are apparent. Two factors are recognized as important in maintaining the fine features of this trace fossil: preservation in flint and, presumably, minimal fluvial transport. Copyright © 2013 John Wiley & Sons, Ltd.
The inner lining of the reptilian brain: A heterogeneous cellular mosaic
Authors: Trujillo‐Cenóz Omar , Marichal Nicolás , Rehermann María Inés , Russo Raúl E.
Published: December 2013

The ependymal layer is a preserved structure across vertebrates but its functional significance remains poorly understood. Modern studies emphasize the role played by radial glia (RG) as neurogenic progenitors. We speculated that the cells lining the prosencephalon ventricles of freshwater turtles may have retained key features of RG. To test this idea, we applied an approach that combined cellular, molecular, fine structural, and electrophysiological techniques. In the prosencephalon of juvenile turtles, we found cells with typical radial morphology that expressed four RG proteins: glial fibrillary acidic protein (GFAP), vimentin, S100/S100β and brain lipid‐binding protein (BLBP). Most of these cells expressed the transcription factor Sox2 but few co‐expressed Pax6. One type of RG had their somata close to the ventricle lumen and bear multiple cilia. A second class with cell bodies far from the lumen was usually uniciliated. RGs had low input resistances, passive properties and were coupled via Cx43 at the level of the cell bodies and radial processes. A third kind of cell was uncoupled, expressed neuronal proteins (HuC/D and NeuN) and fired spikes. The differential expression of HuC/D and NeuN together with their electrophysiological properties suggested various maturational stages. The occurrence of ependymal patches with a high density of 5‐bromo‐2‐deoxyuridine (BrdU) labeled cells provides evidence of the proliferative capability of ependymal RG. Our data support the view that RG have retained key properties of neuroepithelial cells. The maintenance of proliferating RG could be also related with the outstanding endogenous ability of lower vertebrates for self‐repair after injury. GLIA 2014;62:300–316
Broadening Our Understanding and Assessment of Personal and Social Responsibility: A Challenge to Researchers and Practitioners
Authors: Trosset Carol
Published: December 2013

Higher education literature has focused narrowly on social responsibility to the exclusion of personal responsibility. This chapter challenges higher education researchers and practitioners to include behaviors related to personal responsibility in their research and educational agendas.
Benefits of Required Counseling for Counseling Students
Authors: Prosek Elizabeth A. , Holm Jessica M. , Daly Cynthia M.
Published: December 2013

Graduate students experience mental health distress. The authors investigated the benefits of required counseling services at a training clinic for students enrolled in counseling courses. Results indicated that after receiving services, students (N = 55) reported decreases in overall problems, depressive symptoms, and anxiety symptoms. Implications for counselor educators are discussed.
Moral Distress Within the Supervisory Relationship: Implications for Practice and Research
Authors: Nuttgens Simon , Chang Jeff
Published: December 2013

Moral distress is the experience that follows when one feels constrained from acting according to what one believes to be ethically correct. A body of literature from counseling and other health‐related professions indicating the significant impact of morally distressing dynamics on individual and relational well‐being is presented, followed by implications for practice and future research.
Seeking Reemployment in Nonmetropolitan America
Authors: Budnick Christopher J. , Santuzzi Alecia M.
Published: December 2013

Unemployment is particularly pervasive in nonmetropolitan communities with few employment opportunities. The authors examined how unemployed nonmetropolitan adults’ daily affective experiences influenced same‐day and next‐day job search times. Positive affect and high reemployment beliefs were related to higher same‐day, but not next‐day, job search times. Next‐day job search times were higher when job seekers reported high effort and perceived progress on the previous day. Lower job search times occurred after days of low effort with high progress perceptions or if high effort was paired with low progress. Theoretical implications, limitations, and practical applications are discussed.
Case study of the gender earnings gap: a longitudinal analysis of cohort data of same‐department graduates at a small liberal arts college
Authors: Eisenberg Gail R. , Laposata Samuel M.
Published: December 2013

Consistent with similarly conducted studies, the authors found that within a fixed group of men and women, women's salaries fell behind those of men sometime in the later years of their careers. The data and analysis show that the gender‐based wages of the participants in this study diverged quickly after graduation from college, suggesting that men and women make career decisions early, well before children appear in their lives. Those decisions are affected by both labor market discrimination and gender socialization among the participants in this study.
A new size extensive multireference perturbation theory
Authors: Chen Feiwu , Fan Zhihui
Published: December 2013

A new multireference perturbation series is derived based on the Rayleigh–Schrödinger perturbation theory. It is orbitally invariant. Its computational cost is comparable to the single reference Møller–Plesset perturbation theory. It is demonstrated numerically that the present multireference second‐ and third‐order energies are size extensive by two types of supermolecules composed of H2 and BH monomers. Spectroscopic constants of
as well as the ground state energies of H2O, NH2, and CH2 at three bond lengths have been calculated with the second multireference perturbation theory. The dissociation behaviors of CH4 and HF have also been investigated. Comparisons with other approximate theoretical models as well as the experimental data have been carried out to show their relative performances. © 2013 Wiley Periodicals, Inc.
Preparation of Pt@SnO2 Core‐Shell Nanoparticles for Photocatalytic Degradation of Formaldehyde
Authors: Chang Ya‐Chin , Yan Cheng‐Yu , Wu Ren‐Jang
Published: December 2013

We report the synthesis and characterization of platinum‐tin oxide core‐shell nanoparticles (Pt@SnO2) for use as a photocatalyst for formaldehyde (HCHO) degradation. We used a sol‐gel process followed by calcination to prepare the Pt@SnO2 photocatalyst. Transmission Electron Microscopy (TEM) revealed that the average Pt core diameter was 7‐10 nm in diameter, and the SnO2 shell was approximately 2 nm thick. UV‐Visible spectroscopy displayed the peak from the Pt@SnO2 core‐shell structures is red‐shifted by 16 nm from that of the Pt nanoparticles. We determined photocatalytic activity by irradiating formaldehyde gas in the presence of nanoparticle samples with an 18 W daylight lamp for 180 min. The irradiated Pt@SnO2 nanoparticles achieved 93.2% formaldehyde degradation, while TiO2 (P25), SnO2, and 1 wt.% Pt/SnO2 achieved 70.1%, 67.5%, and 66.0% respectively. Thus, Pt@SnO2 was the most effective material for the degradation of formaldehyde, demonstrating its potential for use as a high efficiency photocatalyst for the degradation of formaldehyde.
Synthesis of β‐Haloketones by β‐Addition Reactions of α,β‐Unsaturated Ketones with BX3 (X = Br, Cl) as Halide Source
Authors: Lee Adam Shih‐Yuan , Wang Shu‐Huei , Chang Yu‐Ting
Published: December 2013

A series of β‐bromoketones and β‐chloroketones were synthesized by the addition reactions of α,β‐unsaturated ketones under BX3 (X = Br, Cl) and ethylene glycol reaction system. The α,β‐unsaturated ester also was successfully converted to its corresponding β‐bromoester under the reaction condition.
Transitions between Electron Transporting Mechanisms in Molecular Junctions and Transistors
Authors: Kuo Chun‐Ting , Su Li‐Chen , Chen Chun‐hsien
Published: December 2013

On the extraordinary journey cruising into the interdisciplinary field of molecular electronics by experimentalists, many of the proposed mechanisms for electron transporting across molecular junctions have been witnessed, such as hopping, direct tunneling, thermionic emission, and field emission. For a newcomer to this research field, the terms of the mechanisms can be confusing. This mini‐review is intended to provide a very elementary introduction to the basics of the mechanisms with the help of selected literature examples to make the concept less abstract. In addition to the definition of terminologies used in molecular electronics, the correlation of experimental conditions with the pathways of electron transport is emphasized.
Really Understanding Layered Vanadyl Phosphate Hydrates
Authors: Huang Hui‐Lin , Lii Kwang‐Hwa , Wang Sue‐Lein
Published: December 2013

Layered vanadyl phosphate hydrates with the V/P ratio of 1:1 represent an important class of low‐dimensional phosphate structures as they are of great interest in intercalation chemistry in association with redox catalytic reactions and innovation of light and energy‐saving materials. The inorganic layer of VOPO4 is simple chemically, but is actually complex in inner‐ and inter‐layer structures, and can be based on to induce a diversity of new topologies. There have been obstacles in synthesis as to exploring viable synthetic strategy and understanding the structures in depth. This review provides an up‐to‐date survey to two‐dimensional structures based on 4‐connected VOPO4 layer. For this, all examples so far reported are investigated and presented, including manipulative synthetic parameters, shared structure features, influence of water content in coordination sphere or as guest, and template size and type effects, control of interlayer spacing, and chemical tailoring the inorganicVOPO4 layer.
LOCAL SCARCITY OF ADULT MEN PREDICTS YOUTH ASSAULT RATES
Authors: Kruger Daniel J. , Aiyer Sophie M. , Caldwell Cleopatra H. , Zimmerman Marc A.
Published: December 2013

Father involvement reduces risky youth behavior at the individual level. We examine the association between the scarcity of adult men and youth violence at the Census Tract level across a small midwestern city experiencing decades of economic adversity and high rates of violence. We calculated the ratio of men to women aged 25–64 years and indicators of concentrated disadvantage across residential Census Tracts with 2000 U.S. Decennial Census data and the average monthly assault rates for those aged 10–24 years between June 2006 and December 2008 with data from the local police department. Adult male scarcity and the proportion of individuals aged 25 years or older who had less than a high school degree were the two unique predictors of youth assault rates, together explaining 69% of the variance. Interventions promoting effective social, material, and protective support from fathers and other adult male role models may ameliorate risk for youth violence.
Synthesis of Some New Pyrazole, Pyrimidine, Pyridazine, and Their Fused Derivatives from 3‐Oxo‐3,N‐diphenylpropionamide
Authors: Abdelrazek Fathy M. , Elkholy Yehia M. , Salah Ali M. , Abdelazeem Nagwa M. , Metz Peter
Published: December 2013

The title compounds were obtained from the reactions of 3‐oxo‐3,N‐diphenylpropionamide 3 with dimethylformamide dimethylacetal followed by hydrazine to afford the pyrazole 7, condensation with benzaldehyde followed by cyclocondensation with guanidine to afford the pyrimidine derivative 13, condensation with active methylenes followed by azo coupling of the products followed by cyclization to afford the pyridazines 17a, 17b. The pyridazinone 17b was explored for the synthesis of some novel pyridazine‐fused heterocyclic compounds 19, 21, 24a, 24b, 24c, and 26. All structures were proved via their elemental analyses and spectral data.
Medial meniscal displacement and strain in three dimensions under compressive loads: MR assessment
Authors: Freutel Maren , Seitz Andreas M. , Galbusera Fabio , Bornstedt Axel , Rasche Volker , Knothe Tate Melissa L. , Ignatius Anita , Dürselen Lutz
Published: December 2013

Purpose

To investigate the 3D displacement and the local strain of the medial meniscus and its attachments under compressive loading.

Materials and Methods

Magnetic resonance imaging (MRI) scans of six porcine knee joints were performed under unloaded and loaded conditions (100% and 200% body weight [BW]). Volumes were registered to obtain a 3D displacement field of the medial meniscus and its attachments, which were divided into five anatomic compartments. Finally, displacements of the center of mass of each compartment and the local strain were analyzed.

Results

The meniscus and its attachments significantly displaced by up to 2.6 ± 1.2 mm (P < 0.01) under knee joint loads of 200% BW. An increase of 0.9 mm in the distance between posterior and anterior horn (P < 0.001) was observed. The meniscus and its attachment showed an average radial stretch of 0.6%, an average circumferential stretch of 0.9%, and an average axial compression of 11.6% at 200% BW.

Conclusion

High‐resolution MRI was successfully combined with image registration to investigate the displacement and strain of the meniscus and its attachments under compression. The results of this study contribute to the basic understanding of meniscal movement which may impact the design of meniscal implants and the validation of finite element models in the future.J. Magn. Reson. Imaging 2014;40:1181–1188. © 2013 Wiley Periodicals, Inc.
Membrane‐type 1 metalloproteinase is upregulated in microglia/brain macrophages in neurodegenerative and neuroinflammatory diseases
Authors: Langenfurth Anika , Rinnenthal Jan Leo , Vinnakota Katyayni , Prinz Vincent , Carlo Anne‐Sophie , Stadelmann Christine , Siffrin Volker , Peaschke Susann , Endres Matthias , Heppner Frank , Glass Rainer , Wolf Susanne A. , Kettenmann Helmut
Published: December 2013

We previously reported that glioma cells induce the expression of membrane‐type 1 metalloproteinase (MT1‐MMP or MMP‐14) in tumor‐associated microglia/macrophages and promote tumor growth, whereas MMP‐14 expression in microglia under physiological conditions is very low. Here, we show that the increase in MMP‐14 expression is also found in microglia/macrophages associated with neurodegenerative and neuroinflammatory pathologies in mouse models as well as in human biopsies or post‐mortem tissue. We found that microglial/macrophage MMP‐14 expression was upregulated in Alzheimer's disease tissue, in active lesions of multiple sclerosis, and in tissue from stage II stroke as well as in the corresponding mouse models for the human diseases. In contrast, we observed no upregulation for MMP‐14 in microglia/macrophages in the early phase of stroke or in the corresponding mouse model, in human amyotrophic lateral sclerosis (ALS) tissue or in a mouse model of ALS as well as in human cases of acute brain trauma. These data indicate that MMP‐14 expression is not a general marker for activated microglia/macrophages but is upregulated in defined stages of neuroinflammatory and neurodegenerative diseases and that there is generally a good match between mouse models and human brain pathologies. © 2013 Wiley Periodicals, Inc.
LC–MS/MS method for the characterization of the forced degradation products of Entecavir
Authors: Ramesh Thippani , Rao Pothuraju Nageswara , Rao Ramisetti Nageswara
Published: December 2013

A rapid, specific, and reliable isocratic LC–MS/MS method has been developed and validated for the identification and characterization of the stressed degradation products of Entecavir (ETV). ETV, an antiviral drug, was subjected to hydrolysis (acidic, alkaline, and neutral), oxidation, photolysis and thermal stress, as per the international conference on harmonization specified conditions. The drug showed extensive degradation under oxidative and acid hydrolysis stress conditions. However, it was stable to thermal, acidic, neutral, and photolysis stress conditions. A total of five degradation products were observed and the chromatographic separation of the drug and its degradation products were achieved on a Waters Symmetry C18 (250 mm × 4.6 mm, id, 5 μm) column using 20 mM ammonium acetate (pH 3)/acetonitrile (50:50, v/v) as a mobile phase. The degradation products were characterized by LC–MS/MS and its fragmentation pathways were proposed. The LC–MS method was validated with respect to specificity, linearity, accuracy, and precision. No previous reports were found in the literature regarding the degradation behavior of ETV.
Systematic Studies of Morphological Changes of Precision Polyethylene
Authors: Few Chip S. , Wagener Kenneth B. , Thompson Donovan L.
Published: December 2013

The morphological changes of polyethylenes bearing precisely spaced “defects” are reviewed, focusing on the effects of defect frequency, size, and functionality on crystallization and crystalline structure. The precise defect interval is imparted through acyclic diene metathesis polymerization of structurally symmetric diene monomers. Studies have included structural characterization by differential scanning calorimetry, wide‐angle X‐ray scattering, small‐angle X‐ray scattering (SAXS), and infrared spectroscopy. The collective results are presented separately for functionalized polyethylenes and for those containing alkyl chain branches, as these two classes of polymers vary greatly in morphology.

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Straightforward RAFT Procedure for the Synthesis of Heterotelechelic Poly(acrylamide)s
Authors: Wallyn Sofie , Zhang Zhiyue , Driessen Frank , Pietrasik Joanna , De Geest Bruno G. , Hoogenboom Richard , Du Prez Filip E.
Published: December 2013

Heterotelechelic, hydrophilic polymers with a primary amine and thiol group at the α– and ω‐chain end, respectively, are synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization in a straightforward and versatile way and subsequently used for the design of dual‐responsive polymer/gold nanohybrids. Therefore, a phthalimido‐containing chain transfer agent (CTA) is synthesized and used for the polymerization of the hydrophilic monomers N‐isopropylacrylamide (NIPAM) and N,N‐dimethylacrylamide (DMA). After polymerization, the trithiocarbonate functionality at the ω‐chain end, originating from the CTA, is converted into a thiol upon aminolysis. In the next step, the phthalimido α‐chain end is hydrolyzed into a primary amine, resulting in heterotelechelic, hydrophilic polymers. End‐group conversions are monitored by 1H NMR spectroscopy, MALDI‐TOF MS analysis, and UV–Vis spectroscopy, confirming that quantitative modifications are obtained during each stage. The amino groups of these heterotelechelic polymer chains are modified with citraconic anhydride, after which the obtained polymers are grafted with the thiol group onto citrate‐stabilized gold nanoparticles resulting in the creation of dual‐temperature‐ and pH‐responsive gold particles.

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Incorporation of 5‐Hydroxyindazole into the Self‐Polymerization of Dopamine for Novel Polymer Synthesis
Authors: Peterson Matthew B. , Le‐Masurier Solomon P. , Lim Khoon , Hook James M. , Martens Penny , Granville Anthony M.
Published: December 2013

Investigation into the mussel‐inspired polymerization of dopamine has led to the realization that other compounds possessing potential quinone structures could undergo similar self‐polymerizations in mild buffered aqueous conditions. To this end, 5‐hydroxyindazole was added to a dopamine polymerization matrix in varying amounts, to study its incorporation into a polydopamine coating of silica particles. Solid‐state 13C NMR spectroscopy confirmed the presence of the indazole in the polymer shell when coated onto silica gel. SEM and DLS analysis also confirmed that the presence of the indazole in the reaction matrix yielded monodisperse polymer‐coated particles, which retained their polymer shell upon HF etching, except when high levels of the indazole were used. Characterization data and examination of incorporation mechanism suggests that the 5‐hydroxyindazole performs the function of a chain‐terminating agent. Cytotoxicity studies of the polymer particles containing 5‐hydroxyindazole showed dramatically lower toxicity levels compared to polydopamine alone.

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Fiberfox: Facilitating the creation of realistic white matter software phantoms
Authors: Neher Peter F. , Laun Frederik B. , Stieltjes Bram , Maier‐Hein Klaus H.
Published: December 2013

Purpose

Phantom‐based validation of diffusion‐weighted image processing techniques is an important key to innovation in the field and is widely used. Openly available and user friendly tools for the flexible generation of tailor‐made datasets for the specific tasks at hand can greatly facilitate the work of researchers around the world.

Methods

We present an open‐source framework, Fiberfox, that enables (1) the intuitive definition of arbitrary artificial white matter fiber tracts, (2) signal generation from those fibers by means of the most recent multi‐compartment modeling techniques, and (3) simulation of the actual MR acquisition that allows for the introduction of realistic MRI‐related effects into the final image.

Results

We show that real acquisitions can be closely approximated by simulating the acquisition of the well‐known FiberCup phantom. We further demonstrate the advantages of our framework by evaluating the effects of imaging artifacts and acquisition settings on the outcome of 12 tractography algorithms.

Conclusion

Our findings suggest that experiments on a realistic software phantom might change the conclusions drawn from earlier hardware phantom experiments. Fiberfox may find application in validating and further developing methods such as tractography, super‐resolution, diffusion modeling or artifact correction. Magn Reson Med 72:1460–1470, 2014. © 2013 Wiley Periodicals, Inc.
A New Approach to Spectroscopy
Authors: Bonneville Christophe
Published: December 2013

For more than hundred years, different types of spectrometers based on a dispersive element or an interferometric scanning configuration have been designed and used. Miniaturization of such systems has been achieved, but with each principle there is a trade‐off between miniaturization and performance.
Perceived emotional invalidation and borderline personality disorder features: A test of theory
Authors: Sturrock Bonnie , Mellor David
Published: December 2013

Contemporary theories of borderline personality disorder (BPD) have detailed the functional importance of emotional invalidation in meaningful relationships as an aetiological and perpetuating factor of its core disturbances. The purpose of our study was to test aspects of Linehan's (1993) biosocial and Fruzzetti (1996) and Fruzzetti, Shenk, and Hoffman's (2005) validation/invalidation family interactions transactional theories in a community sample of 186 participants. Results indicated that a multi‐mediational path model of invalidation in meaningful relationships, emotion dysregulation, poor distress tolerance and BPD symptoms provided a perfect fit to the data and accounted for a substantial amount of variance in BPD (38%). The results provided support for these complimentary theories of BPD, which hold promise for clinical applications and future research. Copyright © 2013 John Wiley & Sons, Ltd.
Machine learning applications in proteomics research: How the past can boost the future
Authors: Kelchtermans Pieter , Bittremieux Wout , De Grave Kurt , Degroeve Sven , Ramon Jan , Laukens Kris , Valkenborg Dirk , Barsnes Harald , Martens Lennart
Published: December 2013

Machine learning is a subdiscipline within artificial intelligence that focuses on algorithms that allow computers to learn solving a (complex) problem from existing data. This ability can be used to generate a solution to a particularly intractable problem, given that enough data are available to train and subsequently evaluate an algorithm on. Since MS‐based proteomics has no shortage of complex problems, and since publicly available data are becoming available in ever growing amounts, machine learning is fast becoming a very popular tool in the field. We here therefore present an overview of the different applications of machine learning in proteomics that together cover nearly the entire wet‐ and dry‐lab workflow, and that address key bottlenecks in experiment planning and design, as well as in data processing and analysis.
Nano‐Sized Surface Patterns on Electrospun Microfibers Fabricated Using a Modified Plasma Process for Enhancing Initial Cellular Activities
Authors: Jeon Ho Jun , Lee Hyeongjin , Kim Geun Hyung
Published: December 2013

An easy and versatile method of generating a nano‐sized patterned surface on a nonwoven mat of electrospun poly(ϵ‐caprolactone) (PCL) fibers is described. A nano‐sized pattern could be achieved on the surface of the microfiber mat using a modified plasma‐treatment method with two nano‐sized templates (100 and 800 nm). Initial cell attachment and proliferation using osteoblast‐like‐cells (MG63) were enhanced dramatically compared to a conventional plasma‐treated fiber mat. This new type of plasma‐treated fiber has high potential as a biomaterial, and can be employed for various tissue engineering applications.
Recent Progress on Mesoporous Carbon Materials for Advanced Energy Conversion and Storage
Authors: Wang Jie , Xin Huolin L. , Wang Deli
Published: December 2013

Mesoporous carbon materials have attracted much attention during the past two decades in fields such as energy conversion and storage, gas storage, and medical science. In this progress report, the recent advances of mesoporous‐carbon‐based nanomaterials are presented for fuel cells, lithium batteries, and supercapacitors. A brief discussion of the recent development of synthetic methodologies of mesoporous‐carbon‐based materials is first introduced. Detailed descriptions of the electrochemical properties are stated in each of mesoporous‐carbon‐based materials. Furthermore, comparisons of different mesoporous carbon materials in the same application field are summarized in a table, and some conclusions and disciplines are stated, which may be useful to guide the future studies. Comments on the challenges and perspectives of mesoporous‐carbon‐based materials are proposed for further development.
Sequence, biophysical, and structural analyses of the PstS lipoprotein (BB0215) from Borrelia burgdorferi reveal a likely binding component of an ABC‐type phosphate transporter
Authors: Brautigam Chad A. , Ouyang Zhiming , Deka Ranjit K. , Norgard Michael V.
Published: December 2013

The Lyme disease agent Borrelia burgdorferi, which is transmitted via a tick vector, is dependent on its tick and mammalian hosts for a number of essential nutrients. Like other bacterial diderms, it must transport these biochemicals from the extracellular milieu across two membranes, ultimately to the B. burgdorferi cytoplasm. In the current study, we established that a gene cluster comprising genes bb0215 through bb0218 is cotranscribed and is therefore an operon. Sequence analysis of these proteins suggested that they are the components of an ABC‐type transporter responsible for translocating phosphate anions from the B. burgdorferi periplasm to the cytoplasm. Biophysical experiments established that the putative ligand‐binding protein of this system, BbPstS (BB0215), binds to phosphate in solution. We determined the high‐resolution (1.3 Å) crystal structure of the protein in the absence of phosphate, revealing that the protein's fold is similar to other phosphate‐binding proteins, and residues that are implicated in phosphate binding in other such proteins are conserved in BbPstS. Taken together, the gene products of bb0215‐0218 function as a phosphate transporter for B. burgdorferi.
Resistivity changes of low resistivity Si substrates by rapid thermal processing and subsequent annealing
Authors: Zhang X. , Ma X. , Gao C. , Xu T. , Zhao J. , Dong P. , Vanhellemont J.
Published: December 2013

The resistivity change of low resistivity Si substrates by rapid thermal processing (RTP) and subsequent low tem‐perature annealing is reported. The observed resistivity increase after RTP can be explained by dopant deactivation due to trapping by dopant atoms of intrinsic point defects created during the high temperature step. Similar dopant deactivation is observed during growth of low resistivity single crystals or epitaxial layers.

The stability of the intrinsic point defect‐dopant clusters and the recovery of resistivity is studied by low temperature anneals ranging from 300 to 650 °C. Results are presented on As (3‐5 mΩcm), P (1‐2 mΩcm), (17‐18 mΩcm) and B (16‐17 mΩcm) doped Si substrates. The observations are explained on the basis of a continuum model for intrinsic point point defect trapping by dopants. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Design and simulation of optically controlled field effect transistors
Authors: Sorianello V. , Colace L. , Rajamani S. , Assanto G.
Published: December 2013

Technology roadmaps identify the transmission bottleneck as one of the major challenges at high frequencies and in compact geometries. Increasing bandwidth and massive data processing prompt for the use of optics over short distances, down to board‐to‐board, chip‐to‐chip and even intra‐chip. In this framework, optical to electric converters are key elements. We investigate the feasibility of an optically controlled field effect transistor (FET), a device capable of switching when driven by light (rather than voltage) thanks to a photosensitive gate. We develop a physical model in order to simulate with TCAD the modulation of FET channel conductivity, using drift‐diffusion with optical generation. Current modulation of more than one order of magnitude with 1 µW optical power and time response lower than 100 ps can be achieved. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
New RP‐CVD grown ultra‐high performance selectively B‐doped pure‐Ge 20 nm QWs on (100)Si as basis material for post‐Si CMOS technology
Authors: Mironov O. A. , Hassan A. H. A. , Uhlarz M. , Kiatgamolchai S. , Dobbie A. , Morris R. J. H. , Halpin J. E. , Rhead S. D. , Allred P. , Myronov M. , Gabani S. , Berkutov I. B. , Leadley D. R.
Published: December 2013

Magnetotransport studies at low and room temperature are presented for two‐dimensional hole gases (2DHG) formed in fully strained germanium (sGe) quantum wells (QW). Two designs of modulation doped heterostructure grown by reduced pressure chemical vapour deposition (RP‐CVD) were used and included a normal structure (doping above the Ge channel and inverted structure (doping beneath the Ge channel). The mobility (μH) for the normal structure was measured to be 1.34×106 cm2/Vs with a sheet density (ps) of 2.9×1011cm‐2at 1.5 K, and μH= 3970 cm2/Vs and ps ∼1×1011cm‐2 for room temperature, determined from simulation using the Maximum Entropy‐Mobility Spectrum Analysis (ME‐MSA) method.

For the inverted structure a μH of 4.96×105 cm2/Vs and ps of 5.25×1011cm‐2was measured at 90 mK. From the temperature dependent amplitude of Shubnikov de Haas oscillations, the normal structure was found to have a very low effective mass (m*) value of 0.063 m0 and a ratio of transport to quantum lifetime (α) of ∼78. This extremely high α is indicative of the carrier transport being dominated by small angle scattering from remote impurities i.e. a sample having an extremely low background impurity level and very smooth hetero‐interfaces. The inverted structure had an m*of 0.069 m0 and α ∼29, which also indicates exceedingly high quality material. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrical and optical characterization of extended defects induced in p‐type Si after Si ion implantation
Authors: Nyamhere Cloud , Cristiano Fuccio , Olivie Francios , Bedel‐Pereira Elena , Essa Zahi
Published: December 2013

In this work we present the analysis of small interstitial clusters (ICs) introduced in p‐type Si after ion implantation using deep level transient spectroscopy (DLTS) and photoluminescence. Silicon ions with energy 380 keV and fluence of 1.0 x 1012 cm‐2 have been implanted into bulk p‐type Si and post‐implant annealing at temperatures between 500 oC and 800 oC specifically to create small interstitial cluster (ICs) defects. In the samples annealed at 500 oC, DLTS spectra show deep level hole traps at EV + 0.20 eV, EV + 0.25 eV, EV + 0.36 eV, and EV + 0.50 eV. The hole traps EV + 0.36 eV and EV + 0.50 eV have been attributed to the small Si self‐interstitial clusters. After increasing the post‐implant anneals to 600 oC there is a significant decrease in defect concentration and all the defects are annealed‐out at 700 oC. Photoluminescence (PL) spectroscopy of the samples reveals optical band levels, at 1218 nm (1.019 eV), and 1233 nm (1.007 eV) which have both been attributed to interstitial cluster defects. The interstitial cluster‐related optical band levels have been observed in the samples annealed at 500 oC which correlate well with DLTS measurements. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Atomic scale Monte Carlo simulations of BF3 plasma immersion ion implantation in Si
Authors: La Magna Antonino , Fisicaro Giuseppe , Nicotra Giuseppe , Spiegel Yohann , Torregrosa Frank
Published: December 2013

We present a numerical model aimed to accurately simulate the plasma immersion ion implantation (PIII) process in micro and nano‐patterned Si samples. The code, based on the Monte Carlo approach, is designed to reproduce all the relevant physical phenomena involved in the process. The particle based simulation technique is fundamental to efficiently compute the material modifications promoted by the plasma implantation at the atomic resolution. The accuracy in the description of the process kinetic is achieved linking (one to one) each virtual Monte Carlo event to each possible atomic phenomenon (e.g. ion penetration, neutral absorption, ion induced surface modification, etc.). The code is designed to be coupled with a generic plasma status, characterized by the particle types (ions and neutrals), their flow rates and their energy/angle distributions. The coupling with a Poisson solver allows the simulation of the correct trajectories of charged particles in the void regions of the micro‐structures. The implemented model is able to predict the implantation 2D profiles and significantly support the process design. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Source/drain induced defects in advanced MOSFETs: what device electrical characterization tells
Authors: Mouis Mireille , Lee Jae Woo , Jeon Daeyoung , Shi Ming , Shin Minju , Ghibaudo Gérard
Published: December 2013

A wealth of convergent results are indicating that point defects originating from the processing of source/drain (S/D) regions are strongly involved in many parameters that rule the operation mechanisms and ultimately the performance of transistors. One example of such effect is the mobility degradation which is observed at short gate length in most, if not all, technologies. Defects can also been traced by their implication in leakage currents. Their dynamics has been found as well to be involved in the activation/deactivation processes and the final series resistance of S/D regions, enlightening the role of additional interfaces that are being introduced with thin film SOI and nanowire technologies. These complex effects, which are becoming 3D in present technologies, are very difficult to characterize by means of structural characterization. On the other hand, simulation based predictions have strongly improved. However, due to the complex processes involved, they still require the adjustment of a large number of parameters, which can usually be validated in model configurations only. In this paper we will review and complement some of our recent results obtained from electrical characterization, for a variety of advanced MOS transistor architectures, with focus on the analysis of the parameters which can be influenced by the presence of defects. It is shown that in‐depth electrical characterization can provide strong experimental indications about point defects lateral distribution, with the advantage of probing the real device. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Challenges in CMOS‐based images
Authors: Roy Francois , Tournier A. , Wehbe‐Alause H. , Blanchet F. , Boulenc P. , Leverd F. , Favennec L. , Perrot C. , Pinzelli L. , Gatefait M. , Cherault N. , Jeanjean D. , Carrere J. P. , Augier C. , Ricq S. , Herault D. , Hulot S.
Published: December 2013

High resolution CMOS image sensor demand is driven by consumer applications like mobile phone or digital still camera. To maintain the image quality, we have to save the signal to noise ratio (SNR) despite the number of photons reduction gathered by the pixel. In this paper, we present how back‐side illumination technology could help to recover signal and how to optimize the process and device in order to reduce the noise. A quantum efficiency larger than 70% is targeted to justify efforts done on BSI process development. We also have to pay attention to pixel to pixel crosstalk coming from free carrier diffusion. To overcome this parasitic phenomenon, deep trench isolation (DTI) should be considered in order to significantly reduce crosstalk between two neighboring pixels. The second main noise contributor related to BSI process is the dark current signal. Dark current less than 1 aA per pixel at room temperature is mandatory to save the image quality at low light level. Therefore, all the Si‐SiO2 interfaces at the pixel side walls have to be processed without any process damage to reduce as much as possible the surface defects. On top of that, side wall implantation and side wall dielectric fabrication have been optimized to reduce this noise source. The pixel layout has to be fully optimized also to collect and store charges properly. With respect to the 3D pixel shape, a new fully depleted pinned photodiode with vertical charge storage and no lag has been developed. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis of in vitro fertilization data with multiple outcomes using discrete time‐to‐event analysis
Authors: Maity Arnab , Williams Paige L. , Ryan Louise , Missmer Stacey A. , Coull Brent A. , Hauser Russ
Published: December 2013

In vitro fertilization (IVF) is an increasingly common method of assisted reproductive technology. Because of the careful observation and follow‐up required as part of the procedure, IVF studies provide an ideal opportunity to identify and assess clinical and demographic factors along with environmental exposures that may impact successful reproduction. A major challenge in analyzing data from IVF studies is handling the complexity and multiplicity of outcome, resulting from both multiple opportunities for pregnancy loss within a single IVF cycle in addition to multiple IVF cycles. To date, most evaluations of IVF studies do not make use of full data because of its complex structure. In this paper, we develop statistical methodology for analysis of IVF data with multiple cycles and possibly multiple failure types observed for each individual. We develop a general analysis framework based on a generalized linear modeling formulation that allows implementation of various types of models including shared frailty models, failure‐specific frailty models, and transitional models, using standard software. We apply our methodology to data from an IVF study conducted at the Brigham and Women's Hospital, Massachusetts. We also summarize the performance of our proposed methods on the basis of a simulation study. Copyright © 2013 John Wiley & Sons, Ltd.
Water‐Dispersible, pH‐Stable and Highly‐Luminescent Organic Dye Nanoparticles with Amplified Emissions for In Vitro and In Vivo Bioimaging
Authors: Yu Jia , Diao Xiaojun , Zhang Xiujuan , Chen Xianfeng , Hao Xiaojun , Li Wei , Zhang Xiaohong , Lee Chun‐Sing
Published: December 2013

A new strategy is presented for using doped small‐molecule organic nanoparticles (NPs) to achieve high‐performance fluorescent probes with strong brightness, large Stokes shifts and tunable emissions for in vitro and in vivo imaging. The host organic NPs are used not only as carriers to encapsulate different doped dyes, but also as fluorescence resonance energy transfer donors to couple with the doped dyes (as acceptors) to achieve multicolor luminescence with amplified emissions (AE). The resulting optimum green emitting NPs show high brightness with quantum yield (QY) of up to 45% and AE of 12 times; and the red emitting NPs show QY of 14% and AE of 10 times. These highly‐luminescent doped NPs can be further surface modified with poly(maleic anhydride‐alt‐1‐octadecene)‐polyethylene glycol (C18PMH‐PEG), endowing them with excellent water dispersibility and robust stability in various bio‐environments covering wide pH values from 2 to 10. In this study, cytotoxicity studies and folic acid targeted cellular imaging of these multicolor probes are carried out to demonstrate their potential for in vitro imaging. On this basis, applications of the NP probes in in vivo and ex vivo imaging are also investigated. Intense fluorescent signals of the doped NPs are distinctly, selectively and spatially resolved in tumor sites with high sensitivity, due to the preferential accumulation of the NPs in tumor sites through the passive enhanced permeability and retention effect. The results clearly indicate that these doped NPs are promising fluorescent probes for biomedical applications.
Powder, Paper and Foam of Few‐Layer Graphene Prepared in High Yield by Electrochemical Intercalation Exfoliation of Expanded Graphite
Authors: Wu Liqiong , Li Weiwei , Li Peng , Liao Shutian , Qiu Shengqiang , Chen Mingliang , Guo Yufen , Li Qi , Zhu Chao , Liu Liwei
Published: December 2013

A facile and high‐yield approach to the preparation of few‐layer graphene (FLG) by electrochemical intercalation exfoliation (EIE) of expanded graphite in sulfuric acid electrolyte is reported. Stage‐1 H2SO4‐graphite intercalation compound is used as a key intermediate in EIE to realize the efficient exfoliation. The yield of the FLG sheets (<7 layers) with large lateral sizes (tens of microns) is more than 75% relative to the total amount of starting expanded graphite. A low degree of oxygen functionalization existing in the prepared FLG flakes enables them to disperse effectively, which contributes to the film‐forming characteristics of the FLG flakes. These electrochemically exfoliated FLG flakes are integrated into several kinds of macroscopic graphene structures. Flexible and freestanding graphene papers made of the FLG flakes retain excellent conductivity (≈24 500 S m−1). Three‐dimensional (3D) graphene foams with light weight are fabricated from the FLG flakes by the use of Ni foams as self‐sacrifice templates. Furthermore, 3D graphene/Ni foams without any binders, which are used as supercapacitor electrodes in aqueous electrolyte, provide the specific capacitance of 113.2 F g−1 at a current density of 0.5 A g−1, retaining 90% capacitance after 1000 cycles.
Effect of Water Vapor Content in H2–H2O–CO–CO2 Mixtures on the Equilibrium Distribution of Manganese between CaO–MgOsat–SiO2–Al2O3–FeO–P2O5 Slag and Molten Iron
Authors: Mohassab‐Ahmed M. Yousef , Sohn Hong Yong
Published: December 2013

The equilibrium distribution of manganese between slag and molten iron has been investigated under three different gas environments. MgO‐saturated CaO–FeO–Al2O3–SiO2–MnO (0.2–0.8 wt%)–P2O5 (0.1–0.9 wt%) slags were studied in the temperature range 1550–1600°C under CO/CO2/H2/H2O (natural/coal gas, NG/CG), H2/H2O (H2 reductant), and CO/CO2 with pO2 = 10−10 to 10−9 atm. The first two gas mixtures represented the case of using natural or coal gas and hydrogen in the novel flash ironmaking technology. The average LMn (manganese distribution ratio) was found to be 4, 5, and 6 under CO/CO2/H2/H2O (natural/coal gas), H2/H2O (H2 reductant), and CO/CO2, respectively. In other words, LMn under H2 and natural/coal gas conditions was 29% and 43% less than under the CO/CO2 atmosphere. Therefore, water in the gas atmosphere depresses LMn. When an ore with Mn content of 0.2 wt% is fed into three routes in addition to coke with 0.07 wt% Mn, which was added at the ratio of 0.4 coke‐to‐hot metal in the case of the CO/CO2 gas mixture, the hot metal reduced under the CO/CO2, NG/CG, and H2 conditions, is expected to contain 0.13, 0.14, and 0.15 wt% Mn, respectively. That is H2 and NG/CG are expected to produce hot metal with 17% and 25% more Mn than in the CO/CO2 conditions. This work has for the first time determined the effect of water vapor on the distribution of Mn between slag and molten iron.
Ricean over Gaussian modelling in magnitude fMRI analysis—added complexity with negligible practical benefits
Authors: Adrian Daniel W. , Maitra Ranjan , Rowe Daniel B.
Published: December 2013

It is well known that Gaussian modelling of functional magnetic resonance imaging (fMRI) magnitude time‐course data, which are truly Rice distributed, constitutes an approximation, especially at low signal‐to‐noise ratios (SNRs). Based on this fact, previous work has argued that Rice‐based activation tests show superior performance over their Gaussian‐based counterparts at low SNRs and should be preferred in spite of the attendant additional computational and estimation burden. Here, we revisit these past studies and, after identifying and removing their underlying limiting assumptions and approximations, provide a more comprehensive comparison. Our experimental evaluations using Receiver Operating Characteristic (ROC) curve methodology show that tests derived using Ricean modelling are substantially superior over the Gaussian‐based activation tests only for SNRs below 0.6, that is, SNR values far lower than those encountered in fMRI as currently practiced.Copyright © 2013 John Wiley & Sons, Ltd.