bluuebunny/crossref_metadata_2025 huggingface dataset:
Client Perceptions of the Value of Microinsurance: Evidence from Southern Ghana
Authors: Giesbert Lena , Steiner Susan
Published: January 2015

The uptake of microinsurance in developing countries falls short of projections, which has recently made stakeholders focus on client value. This article investigates when and why clients of a micro life insurance product in Ghana perceive value, using data from focus group discussions. We show that value depends not only on costs and monetary benefits but also on the service quality, emotions and social benefits that are associated with the product. Perceptions of high or low value can be explained by how expectations compare with actual experiences with the insurance as well as the specific client context. Peers strongly influence each other in their value perceptions. Copyright © 2015 John Wiley & Sons, Ltd.
Which comes first, organizational culture or performance? A longitudinal study of causal priority with automobile dealerships
Authors: Boyce Anthony S. , Nieminen Levi R. G. , Gillespie Michael A. , Ryan Ann Marie , Denison Daniel R.
Published: January 2015

Prior research supports a link between organizational culture and performance but generally falls short of establishing causality or determining the direction of a culture–performance (C‐P) relationship. Using data collected from 95 franchise automobile dealerships over 6 years, we studied longitudinal culture–performance relationships to determine whether culture or performance has causal priority, or alternatively, whether a reciprocal relationship exists. Results from cross‐lagged panel analyses indicate that culture “comes first,” consistently predicting subsequent ratings of customer satisfaction and vehicle sales. Furthermore, the positive effect of culture on vehicle sales is fully mediated by customer satisfaction ratings. Copyright © 2015 John Wiley & Sons, Ltd.
Convergence and emergence in organizations: An integrative framework and review
Authors: Fulmer C. Ashley , Ostroff Cheri
Published: January 2015

In reaction to the growing attention to connecting individual‐level and unit‐level constructs, we first briefly review emergence terminology and theories that address the dynamic process by which a higher‐level phenomenon emerges from lower‐level elements. Next, we review the extant theory and research on emergence and convergence in organization science using an organizing framework that simultaneously considers the content area of lower‐level elements, the emergent factors, and the target of the emergent property. In addition to organizing and bridging current literature on emergence and convergence, gaps of existing research and new directions for future research, including compilation and divergence, are identified. Copyright © 2015 John Wiley & Sons, Ltd.
Midlatitude cyclones in the southeastern United States: frequency and structure differences by cyclogenesis region
Authors: Nieto Ferreira Rosana , Earl Hall Linwood
Published: January 2015

Midlatitude cyclones that affected the Southeast (SE) United States between 1998 and 2010 were classified into five types according to their region of origin: (1) Continental United States, (2) Canadian, (3) Gulf Low, (4) Hatteras Low, or (5) Stationary. A composite analysis was used to examine differences in the structure, evolution, and propagation of these cyclones during boreal winter, when the largest number of cyclones affect the SE United States. Most of the midlatitude cyclones that affect the SE in the wintertime formed within the continental United States (∼11 events/winter), followed by Gulf Lows (∼4 events/winter) and Canadian cyclones (∼4 events/winter). Hatteras Lows were relatively rare (∼1 events/winter), and Stationary events did not occur during winter. While Canadian and Continental US cyclones occurred year‐round the frequency of Gulf Low events peaked in the boreal winter when the upper‐level jet was strongest and located further south. Hatteras Lows peaked in the boreal fall and winter, and Stationary events occurred almost exclusively during the boreal summer. Overall, Gulf Low and Continental US cyclones were the only cyclones that brought wintertime precipitation to the SE United States. When integrated over the season, Continental US cyclones made the largest contribution to the wintertime precipitation in the SE United States. On a per‐event basis, however, Gulf Lows were the biggest wintertime precipitation makers in the SE United States while Canadian cyclones and Hatteras Lows did not bring much precipitation to the SE United States. Gulf Lows were more common during El Niño than La Niña years and tended to occur back‐to‐back with either another Gulf Low or with a Hatteras Low.
Trend analysis of tropical intraseasonal oscillations in the summer and winter during 1982–2009
Authors: Tao Li , Zhao Jiuwei , Li Tim
Published: January 2015

Based on the daily outgoing long‐wave radiation data of the National Oceanic and Atmospheric Administration from 1979 to 2012, we investigated the intensity changes of the 20‐ to 70‐day boreal summer (June–September, JJAS) intraseasonal oscillation (BSISO) and winter (December–February, DJF) intraseasonal oscillation, also known as the Madden–Julian Oscillation (MJO). The results showed that the intensity of the BSISO has a significant intensifying trend during 1982–2009. On the other hand, little trend was found for boreal winter MJO during this period. The wavenumber‐frequency analysis was applied to separate ISO into westward propagation and eastward propagation parts. The significant intensified trend was observed over tropical Indian Ocean for the eastward propagation BSISO. The weakened but not significant trend was observed over southern tropical Indian Ocean for the eastward propagation MJO. To gain insight into the different ISO characteristics, the tendencies of sea surface temperature (SST) and the vertical shear of zonal wind were analysed. The results showed that in both seasons from 1982 to 2009, the global SST trends were similar, and thus they could not be used to explain the BSISO upward trend. However, lower tropospheric easterly shear in boreal summer over tropical Indian Ocean had a decreasing trend, while the easterly vertical shear over maritime continent was enhanced in winter. It is proposed that the reduced easterly vertical shear over tropical Indian Ocean favoured the amplification of the eastward propagating Kelvin wave, which led to the intensified eastward propagating BSISO. The enhanced easterly vertical shear over maritime continent might be unfavourable to the amplification of the eastward propagating Kelvin wave, but its impact was offset by the enhanced upward motion over maritime continent. As a result, there was little trend of the MJO in boreal winter. The above hypothesis was further verified by intermediate model results.
A Fourier transform Raman spectrometer with visible laser excitation
Authors: Dzsaber S. , Negyedi M. , Bernáth B. , Gyüre B. , Fehér T. , Kramberger C. , Pichler T. , Simon F.
Published: January 2015

We present the development and performance of a Fourier transformation (FT)‐based Raman spectrometer working with visible laser (532 nm) excitation. It is generally thought that FT‐Raman spectrometers are not viable in the visible range where shot noise limits the detector performance and therein they are outperformed by grating based, dispersive ones. We show that contrary to this common belief, the recent advances of high‐performance interference filters makes the FT‐Raman design a valid alternative to dispersive Raman spectrometers for samples which do not luminesce. We critically compare the performance of our spectrometer to two dispersive ones: a home‐built single channel and a state‐of‐the‐art charge coupled device‐based instruments. We demonstrate a similar or even better sensitivity than the charge coupled device‐based dispersive spectrometer particularly when the laser power density is considered. The instrument possesses all the known advantages of the FT principle of spectral accuracy, high throughput, and economic design. We also discuss the general considerations, which helps the community reassess the utility of the different Raman spectrometer designs. Copyright © 2015 John Wiley & Sons, Ltd.
FTIR micro‐reflectance absorption spectroscopic analysis of chemisorbed reaction films for tribological applications
Authors: Choudhary R. B. , Tyagi O. S. , Anand O. N.
Published: January 2015

Chemisorbed reaction films (CRFs) were prepared by using iron (Fe) particles (100–200 mess size) and thio (sulfur) derivatives of ethyl octadecenoate and methyl 12‐hydroxy octadecenoate in the light viscosity paraffin liquid medium. The reaction was conducted in a simulated condition of tribo‐chemical situation. CRFs were obtained in solid amorphous phase. The CRFs were examined for elemental composition and layer analysis using C‐H‐N‐O‐S analyzer and Fourier transform infrared spectroscopy micro‐reflectance absorption spectroscopic technique. Further, the CRFs were isolated into organic solvent soluble fractions using polar solvents of increasing polar strength. Their elemental analyses were studied, and chemical constitutions were known. Friction coefficient and wear scar diameter were evaluated by high frequency reciprocating rig, PLINT TE‐77 machine. Thermal stability was studied using thermogravimetric analysis technique in nitrogen environment. These studies inferred that CRFs appeared varying in its composition, luster, phase, chemical structure and thermal stability. Nonetheless, these were also found anomalous in elemental distribution throughout the layer structure of the CRFs. Copyright © 2015 John Wiley & Sons, Ltd.
Thermo‐mechanical characterization of bioblends from polylactide and poly(butylene adipate‐co‐terephthalate) and lignin
Authors: Abdelwahab Mohamed A. , Taylor Sarah , Misra Manjusri , Mohanty Amar K.
Published: January 2015

This paper investigates the effect of the incorporation of organosolv lignin and a chain extender on the compatibility between polylactide and poly(butylene adipate‐co‐terephthalate). Bioblends were processed using melt extrusion and injection molding techniques. A reaction was observed during the melt processing as the force increased as the amount of ADR in the formulation increased. This reaction was investigated by Fourier transform infrared spectroscopy. The morphological images showed a good dispersion and an absence of phase separation by the inclusion of the chain extender. The incorporation of the chain extender enhanced the tensile properties and modulus characterization of the bioblends. Dynamic mechanical analysis and rheological characterization revealed that the addition of chain extender increased the storage modulus of the bioblends. Differential scanning calorimetry analysis showed a good miscibility between PLA and PBAT in the presence of OL and the chain extender, while thermogravimetric analysis showed enhancement in the thermal stability by inclusion of the chain extender.
Electrified Polyolefin/Multiwall Carbon Nanotube Composites Exhibit Dramatic Changes in Electrical Conductivity, Permittivity, and Filler Structure
Authors: Osazuwa Osayuki , Kontopoulou Marianna , Sabat Ribal Georges , Docoslis Aristides
Published: January 2015

Electrically insulating polyolefin composites containing well‐dispersed multiwall carbon nanotubes up to 3 wt.‐% are subjected to AC electric fields in the range of 71–212 kV m−1. Their resulting filler structure, DC conductivity, and AC dielectric properties are compared with the respective properties of their non‐electrified and annealed counterparts. As evidenced by TEM, electrification causes the formation of aligned filler structures in the direction of the electric field within the composite, whereas annealing alone results in the formation of randomly interconnected nanotubes. Dielectric spectroscopy shows that, due to their ordered carbon nanotube structures, the electrified composites exhibit substantially higher conductivity and storage capacity compared to the as‐compounded composites and consistently better electrical properties than their annealed counterparts. An equivalent circuit model is fitted to the experimentally obtained impedance data in order to correlate the effects of electric field and processing time to the resulting dielectric characteristics of the treated composites.
Reinforced Degradable Biocomposite by Homogenously Distributed Functionalized Nanodiamond Particles
Authors: Sun Yang , Finne‐Wistrand Anna , Waag Thilo , Xing Zhe , Yassin Mohamed , Yamamoto Akihito , Mustafa Kamal , Steinmüller‐Nethl Doris , Krueger Anke , Albertsson Ann‐Christine
Published: January 2015

Severe phase separation was observed in blending nanodiamond particle (n‐DP) in poly(L‐lactide‐co‐ε‐caprolactone) (poly(LLA‐co‐CL)) scaffold. In this study we optimized the scaffold by the addition of 1–50% (w/w) polylactide modified n‐DP (n‐DP‐PLA) or benzoquinone‐modified n‐DP (n‐DP‐BQ). Composed by 10% n‐DP‐PLA, composite had 6 times higher E‐modulus in tensile test, whereas the maximum reinforcement can be higher than 15 times. However, n‐DP‐BQ composites conserved the mechanical properties, and thermal properties of the polymer substrate. The attachment, spreading and growth of UE7T13 cells on modified n‐DP composites were similar to poly(LLA‐co‐CL), and independent to n‐DP concentrations. In summary, a proper modified n‐DP is the key to reinforce poly(LLA‐co‐CL) for tissue engineering.
Self‐organized Polymer Wrinkles: A Lithography‐free Pathway for Surface‐enhanced Raman Scattering (SERS) Substrates
Authors: Stenberg Henna , Matikainen Antti , Daniel Salman , Nuutinen Tarmo , Stenberg Petri , Honkanen Seppo , Pakkanen Tuula , Vahimaa Pasi , Suvanto Mika
Published: January 2015

Self‐organized pattern formation is a phenomenon that can be used for nanoscale pattering of large surface areas in a cost‐effective manner. We exploit the phenomenon and fabricate sub‐micron polystyrene wrinkle structures and demonstrate that after being coated with silver, they can be used as surface‐enhanced Raman spectroscopy (SERS) substrates. We show that the signal enhancement generated by the wrinkles is 8 times higher in comparison to a flat reference while the measurement repeatability is simultaneously improved (variation reduced from 30 to 13%). The results indicate that self‐organization could be further utilized in cost‐effective, large‐scale production of SERS substrates.
One‐Pot Preparation of 3D Nano‐ and Microaggregates via In Situ Nanoparticlization of Polyacetylene Diblock Copolymers Produced by ROMP
Authors: Yoon Ki‐Young , Shin Suyong , Kim Yong‐Jae , Kim Inhye , Lee Eunji , Choi Tae‐Lim
Published: January 2015

Zero‐dimensional (0D) nanospheres, 1D nanocaterpillars, and 3D aggregates are produced from simple diblock copolymers containing polyacetylene (PA) via in situ nanoparticlization of conjugated polymers. The diblock copolymers are prepared by ring‐opening metathesis polymerization via one‐pot sequential addition of an endo‐tricyclo[4.2.2.0]deca‐3,9‐diene (TD) and cyclooctatetraene. Initially, they spontaneously form nanospheres consisting of a PA core and PTD shell, and increasing the length of the PA block leads to the direct nanoparticlization of the higher‐dimensional structures such as 1D and 3D aggregates because of the decreased effective volume ratio of the rigid PTD shell to the solvophobic PA core.

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Tissue inhibitor of matrix metalloproteinase‐1 expression in colorectal cancer liver metastases is associated with vascular structures
Authors: Illemann Martin , Eefsen Rikke Helene Løvendahl , Bird Nigel Charles , Majeed Ali , Osterlind Kell , Laerum Ole Didrik , Alpízar‐Alpízar Warner , Lund Ida Katrine , Høyer‐Hansen Gunilla
Published: January 2015

Metastatic growth by colorectal cancer cells in the liver requires the ability of the cancer cells to interact with the new microenvironment. This interaction results in three histological growth patterns of liver metastases: desmoplastic, pushing, and replacement. In primary colorectal cancer several proteases, involved in the degradation of extracellular matrix components, are up‐regulated. In liver metastases, their expression is growth pattern dependent. Tissue inhibitor of matrix metalloproteinase‐1 (TIMP‐1) is a strong prognostic marker in plasma from colorectal cancer patients, with significant higher levels in patients with metastatic disease. We therefore wanted to determine the expression pattern of TIMP‐1 in primary colorectal cancers and their matching liver metastases. TIMP‐1 mRNA was primarily seen in α‐smooth‐muscle actin (α‐SMA)‐positive cells. In all primary tumors and liver metastases with desmoplastic growth pattern, TIMP‐1 mRNA was primarily found in α‐SMA‐positive myofibroblasts located at the invasive front. Some α‐SMA‐positive cells with TIMP‐1 mRNA were located adjacent to CD34‐positive endothelial cells, identifying them as pericytes. This indicates that TIMP‐1 in primary tumors and liver metastases with desmoplastic growth pattern has dual functions; being an MMP‐inhibitor at the cancer periphery and involved in tumor‐induced angiogenesis in the pericytes. In the liver metastases with pushing or replacement growth patterns, TIMP‐1 was primarily expressed by activated hepatic stellate cells at the metastasis/liver parenchyma interface. These cells were located adjacent to CD34‐positive endothelial cells, suggesting a function in tumor‐induced angiogenesis. We therefore conclude that TIMP‐1 expression is growth pattern dependent in colorectal cancer liver metastases. © 2015 The Authors. Molecular Carcinogenesis published by Wiley Periodicals, Inc.
Rheb promotes cancer cell survival through p27Kip1‐dependent activation of autophagy
Authors: Campos Tania , Ziehe Javiera , Palma Mario , Escobar David , Tapia Julio C. , Pincheira Roxana , Castro Ariel F.
Published: January 2015

We previously found that the small GTPase Rheb regulates the cell‐cycle inhibitor p27KIP1 (p27) in colon cancer cells by a mTORC1‐independent mechanism. However, the biological function of the Rheb/p27 axis in cancer cells remains unknown. Here, we show that siRNA‐mediated depletion of Rheb decreases survival of human colon cancer cells under serum deprivation. As autophagy can support cell survival, we analyzed the effect of Rheb on this process by detecting the modification of the autophagy marker protein LC3 by western blot and imunofluorescence. We found that Rheb promotes autophagy in several human cancer cell lines under serum deprivation. Accordingly, blocking autophagy inhibited the pro‐survival effect of Rheb in colon cancer cells. We then analyzed whether p27 was involved in the biological effect of Rheb. Depletion of p27 inhibited colon cancer cell survival, and Rheb induction of autophagy. These results suggest that p27 has an essential role in the effect of Rheb in response to serum deprivation. In addition, we demonstrated that the role of p27 in autophagy stands on the N‐terminal portion of the protein, where the CDK‐inhibitory domain is located. Our results indicate that a Rheb/p27 axis accounts for the activation of autophagy that supports cancer cell survival. Our work therefore highlights a biological function of Rheb and prompts the need for future studies to address whether the mTORC1‐independent Rheb/p27 axis could contribute to tumorigenesis and/or resistance to mTOR inhibitors. © 2015 Wiley Periodicals, Inc.
[11C]‐(+)‐PHNO PET imaging of dopamine D2/3 receptors in Parkinson's disease with impulse control disorders
Authors: Payer Doris E. , Guttman Mark , Kish Stephen J. , Tong Junchao , Strafella Antonio , Zack Martin , Adams John R. , Rusjan Pablo , Houle Sylvain , Furukawa Yoshiaki , Wilson Alan A. , Boileau Isabelle
Published: January 2015

Dopamine agonist medications with high affinity for the D3 dopamine receptor are commonly used to treat Parkinson's disease, and have been associated with pathological behaviors categorized under the umbrella of impulse control disorders (ICD). The aim of this study was to investigate whether ICD in Parkinson's patients are associated with greater D3 dopamine receptor availability. We used positron emission tomography (PET) radioligand imaging with the D3 dopamine receptor preferring agonist [11C]‐(+)‐propyl‐hexahydro‐naphtho‐oxazin (PHNO) in Parkinson's patients with (n = 11) and without (n = 21) ICD, and age‐, sex‐, and education‐matched healthy control subjects (n = 18). Contrary to hypotheses, [11C]‐(+)‐PHNO binding in D3‐rich brain areas was not elevated in Parkinson's patients with ICD compared with those without; instead, [11C]‐(+)‐PHNO binding in ventral striatum was 20% lower (P = 0.011), correlating with two measures of ICD severity (r = −0.8 and −0.9), which may reflect higher dopamine tone in ventral striatum. In dorsal striatum, where [11C]‐(+)‐PHNO binding is associated with D2 receptor levels, [11C]‐(+)‐PHNO binding was elevated across patients compared with controls. We conclude that although D3 dopamine receptors have been linked to the occurrence of ICD in Parkinson's patients. Our findings do not support the hypothesis that D3 receptor levels are elevated in Parkinson's patients with ICD. We also did not find ICD‐related abnormalities in D2 receptor levels. Our findings argue against the possibility that differences in D2/3 receptor levels can account for the development of ICD in PD; however, we cannot rule out that differences in dopamine levels (particularly in ventral striatum) may be involved. © 2015 International Parkinson and Movement Disorder Society
Subthalamic deep brain stimulation differently alters striatal dopaminergic receptor levels in rats
Authors: Carcenac Carole , Favier Mathieu , Vachez Yvan , Lacombe Emilie , Carnicella Sébastien , Savasta Marc , Boulet Sabrina
Published: January 2015

High‐frequency stimulation (HFS) of the subthalamic nucleus (STN) is recognized as an effective treatment for the motor symptoms of Parkinson's disease (PD), but its mechanisms, particularly as concern dopaminergic transmission, remain unclear. The aim of this study was to evaluate changes in the expression of dopaminergic receptors (D1, D2, and D3 receptors) after prolonged (4 h) unilateral STN‐HFS in anesthetized intact rats and rats with total dopaminergic denervation. We used [3H]SCH 23390, [125I]iodosulpride, and [125I]OH‐PIPAT to assess the densities of D1R, D2R, and D3R, respectively, within different areas of the striatum—a major input structure of the basal ganglia—including the nucleus accumbens. We found that STN‐HFS increased D1R levels in almost all of the striatal areas examined, in both intact and denervated rats. By contrast, STN‐HFS led to a large decrease in D2R and D3R levels, limited to the nucleus accumbens and independent of the dopaminergic state of the animals. These data suggest that the influence of STN‐HFS on striatal D1R expression may contribute to its therapeutic effects on motor symptoms, whereas its impact on D2R/D3R levels in the nucleus accumbens may account for the neuropsychiatric side effects often observed in stimulated PD patients, such as postoperative apathy. © 2015 International Parkinson and Movement Disorder Society
Statins, plasma cholesterol, and risk of Parkinson's disease: A prospective study
Authors: Huang Xuemei , Alonso Alvaro , Guo Xuguang , Umbach David M. , Lichtenstein Maya L. , Ballantyne Christie M. , Mailman Richard B. , Mosley Thomas H. , Chen Honglei
Published: January 2015

Previous findings on the association of statins, plasma lipids, and Parkinson's disease (PD) are confounded by the fact that statins also affect lipid profiles. We prospectively examined plasma lipids and statin use in relation to PD in the Atherosclerosis Risk in Communities (ARIC) Study. Statin use and plasma lipids were assessed at baseline (visit 1, 1987‐89) and at three triennial visits thereafter (visits 2‐4) until 1998. Potential PD cases were identified from multiple sources and validated where possible. The primary analysis was limited to incident PD cases diagnosed between 1998 and 2008. Odds ratios and 95% confidence intervals were derived from multivariate logistic regression models. Statin use was rare at baseline (0.57%) but increased to 11.2% at visit 4. During this time frame, total‐cholesterol levels decreased, particularly among statin users. Fifty‐six PD cases were identified after 1998. Statin use before 1998 was associated with significantly higher PD risk after 1998 (odds ratio = 2.39, 95% confidence interval 1.11‐5.13) after adjusting for total cholesterol and other confounders. Conversely, higher total cholesterol was associated with lower risk for PD after adjustment for statin usage and confounders. Compared with the lowest tertile of average total cholesterol, the odds ratios for PD were 0.56 (0.30‐1.04) for the second and 0.43 (0.22‐0.87) for the third tertile (Ptrend = 0.02). Statin use may be associated with a higher PD risk, whereas higher total cholesterol may be associated with lower risk. These data are inconsistent with the hypothesis that statins are protective against PD. © 2015 International Parkinson and Movement Disorder Society
Translational Horizons in the Tumor Microenvironment: Harnessing Breakthroughs and Targeting Cures
Authors: Sun Yu
Published: January 2015

Chemotherapy and targeted therapy have opened new avenues in clinical oncology. However, there is a lack of response in a substantial percentage of cancer patients and diseases frequently relapse in those who even initially respond. Resistance is, at present, the major barrier to conquering cancer, the most lethal age‐related pathology. Identification of mechanisms underlying resistance and development of effective strategies to circumvent treatment pitfalls thereby improving clinical outcomes remain overarching tasks for scientists and clinicians. Growing bodies of data indicate that stromal cells within the genetically stable but metabolically dynamic tumor microenvironment confer acquired resistance against anticancer therapies. Further, treatment itself activates the microenvironment by damaging a large population of benign cells, which can drastically exacerbate disease conditions in a cell nonautonomous manner, and such off‐target effects should be well taken into account when establishing future therapeutic rationale. In this review, we highlight relevant biological mechanisms through which the tumor microenvironment drives development of resistance. We discuss some unsolved issues related to the preclinical and clinical trial paradigms that need to be carefully devised, and provide implications for personalized medicine. In the long run, an insightful and accurate understanding of the intricate signaling networks of the tumor microenvironment in pathological settings will guide the design of new clinical interventions particularly combinatorial therapies, and it might help overcome, or at least prevent, the onset of acquired resistance.
Correlation Between Mechanical Properties and Cross‐Linking Degree of Ethyl Lactate Plasma Polymer Films
Authors: Ligot Sylvie , Bousser Etienne , Cossement Damien , Klemberg‐Sapieha Jolanta , Viville Pascal , Dubois Philippe , Snyders Rony
Published: January 2015

Plasma polymer films are more and more used in numerous applications such as the day‐to‐day packaging, which requires a good mechanical resistance of the coating. Since mechanical properties are function of the cross‐linking degree of the thin films, it is important to understand the relationship between the two. In this work, plasma polymer films were studied in terms of cross‐linking degree and mechanical properties, measured by means of ToF‐SIMS coupled to PCA and depth‐sensing nanoindentation, respectively. The data reveal that when the power increases, the films are more cross‐linked and show higher hardness, higher elastic recovery, lower creep strain and an increased ability for self‐healing. As the plasma polymer films are more cross‐linked, the plasticity drops and the viscoelasticity and hardness increase.
Reduction of the thermal budget of AlGaN/GaN heterostructures grown on silicon: A step towards monolithic integration of GaN‐HEMTs with CMOS
Authors: Comyn Rémi , Cordier Yvon , Aimez Vincent , Maher Hassan
Published: January 2015

In this paper, we investigate the reduction of thermal budgets associated with the growth of GaN high electron mobility transistor (HEMT) heterostructures. The reduction of such thermal budgets is desirable for the monolithic integration of GaN‐HEMT with CMOS circuits, when the latter are fabricated first. Indeed, due to the elevated temperatures required for the growth of III‐nitrides, the characteristics of the integrated CMOS devices may drift during the process. In order to determine in which extend the growth thermal budget could be reduced without penalty on the performances of GaN‐HEMTs, different structures were grown by ammonia‐molecular beam epitaxy (ammonia‐MBE) with standard and reduced growth temperatures. The epitaxial structures were then compared with regards to their structural and electrical properties. The present work sets the limit for a potential trade‐off between Si‐CMOS and GaN‐HEMTs degradation in a CMOS‐first monolithic integration scenario.
Formation of Er‐germanosilicide films on strained Si1−xGex with different Ge contents
Authors: Choi Seongheum , Choi Juyun , Kim Hyoungsub
Published: January 2015

Er‐germanosilicide [Er(Si1−zGez)2−y] films were formed on strained Si1−xGex layers with different Ge contents (x = 0.14 and 0.28), and their dependency of formation kinetics on the Ge concentrations was investigated while minimizing the oxygen‐incorporation effect using a TaN capping layer. When a ~30 nm‐thick Er film was used, uniform Er(Si1−zGez)2−y films were obtained at an annealing temperature of around 600 °C without their agglomeration and also the strain relaxation of the remaining Si1−xGex layer. The increase in the Ge concentration of the reacting Si1−xGex layer enhanced the formation of the crystalline Er(Si1−zGez)2−y film. Furthermore, some enrichment of the Ge content within the Er(Si1−zGez)2−y film occurred in comparison with that in the initial and remaining Si1−xGex layers.
McLafferty‐type rearrangement of protonated N‐[nicotinoyl]phenylethyl amines and consequent elimination of styrene
Authors: Paulose Justin , Achuthan Revi P. , Mathai George , Chander Purna , Srinivas Ragampeta
Published: January 2015

Rationale

McLafferty rearrangements occur in radical cations of molecules containing a carbonyl group and a γ hydrogen atom but are not common in the [M+H]+ ions of carbonyl compounds. We propose to investigate the collision‐induced dissociation (CID) of the [M+H]+ ions of nicotinoyl and picolinoyl amides of 1‐ and 2‐phenylethylamines to explore the possibility of McLafferty‐type rearrangement.

Methods

The compounds for study were synthesized by the reaction of methyl nicotinate or methyl picolinate with 1‐ and 2‐phenylethylamines. The CID mass spectra of electrospray ionization (ESI)‐generated protonated molecules were obtained using a QSTAR XL quadrupole time‐of‐flight (QTOF) mass spectrometer, and density functional theory (DFT) calculations using the B3LYP method were employed to elucidate the fragmentation mechanisms. The total electronic and thermal energies of intermediate transition states (TSs) and product ions are reported relative to those of the [M+H]+ ions.

Results

CID of the [M+H]+ ions of N‐[nicotinoyl]‐2‐phenylethylamine (1) yielded product ions of m/z 105 (1‐phenylethyl cation) and 123 ([M+H–styrene]+ cation). The competitive formation of the ions of m/z 123 and 105 is proposed to involve a McLafferty‐type rearrangement. Similarly, the [M+H]+ ions of the isomeric compound 2 and the N‐[picolinoyl] phenylethyl amines (3 and 4) dissociate to yield ions of m/z 123 and 105.

Conclusions

A molecule of styrene was eliminated from the ESI‐generated [M+H]+ ions of N‐[nicotinoyl]phenylethylamines and the isomeric N‐[picolinoyl]phenylethylamines, through a mechanism involving a McLafferty‐type 1,5‐H shift. The transition state energy for the 1,5‐H shift is less for the amides of 1‐phenylethylamine than for the amides of 2‐phenylethylamine. The process occurs as a charge remote process and the presence of the pyridine ring is essential for the process. Copyright © 2015 John Wiley & Sons, Ltd.
A new high‐quality set of singly (2H) and doubly (2H and 18O) stable isotope labeled reference waters for biomedical and other isotope‐labeled research
Authors: Faghihi V. , Verstappen‐Dumoulin B. M. A. A. , Jansen H. G. , van Dijk G. , Aerts‐Bijma A. T. , Kerstel E. R. T. , Gröning M. , Meijer H. A. J.
Published: January 2015

RATIONALE

Research using water with enriched levels of the rare stable isotopes of hydrogen and/or oxygen requires well‐characterized enriched reference waters. The International Atomic Energy Agency (IAEA) did have such reference waters available, but these are now exhausted. New reference waters thus had to be produced in sufficient quantity, and higher characterization quality was desired.

METHODS

The reference waters have been prepared gravimetrically from three parent waters: natural water, pure 2H water and highly 18O‐enriched water. These parent waters have been thoroughly assessed for their full isotopic compositions. To ensure the integrity and correctness of the gravimetric procedure, validation measurements have been carried out on the isotopic composition of the produced reference waters by two of our laboratories. These measurements corroborate the values obtained on the basis of gravimetric data.

RESULTS

Two new sets of three reference waters enriched in the stable isotopes have been produced and certified: one set of singly labeled waters, only enriched in 2H, and another set of Doubly Labeled Waters, enriched in both 2H and 18O. They cover δ2H and δ18O values in the range of 800–16000 ‰ and 100–2000 ‰, respectively. The process has led to highly accurate isotopic values for these waters.

CONCLUSIONS

These reference waters are now available (called IAEA‐604 to IAEA‐609). They will be valuable as reference materials for all fields using isotope labeling of water, most prominently, but not exclusively, biomedical research (body composition analyses, metabolic rate measurements). The two waters with the lowest enrichments will also be useful as anchor values for isotope measurements around the natural range. © 2015 The Authors. Rapid Communications in Mass Spectrometry published by John Wiley & Sons Ltd.
Identification of effective substrates for the direct analysis of lipids from cell lines using desorption electrospray ionization mass spectrometry
Authors: Srimany Amitava , Jayashree Balasubramanyam , Krishnakumar Subramanian , Elchuri Sailaja , Pradeep Thalappil
Published: January 2015

Rationale

Various disease conditions, particularly tumours, can be understood easily by studying changes in the lipid profile of cells. While lipid profiles of tissues have been recorded by desorption electrospray ionization mass spectrometric (DESI‐MS) imaging, there is paucity in standardized protocols for sample preparation involving cell cultures to generate reliable results. In this study, we report a method for the direct analysis of lipids from cultured cells by incorporating them onto Whatman 42 filter paper as a substrate for reliable DESI‐MS analysis.

Methods

The WERI‐RB1 cell line was spotted on commonly used substrates for DESI‐MS analysis, such as glass slides, Teflon coated glass slides, thin layer chromatography (TLC) plates, and Whatman 42 filter paper. A comparison of mass spectrometric images with two different lipids was made to understand the behaviour of different surfaces when the same sample was spotted on them. Relative intensities of different lipid peaks in the WERI‐RB1 cell line were compared and relative lipid abundances were also compared across two different human retinoblastoma cell lines; WERI‐RB1 and Y79.

Results

The study demonstrates that good lipid signals can be obtained by DESI‐MS when the cells are spotted on Whatman 42 filter paper. Tandem mass spectrometry was performed to identify the lipids as glycerophosphocholines (PC). Better lipid images from assembly of cells were obtained with distinct boundary when they were spotted on Whatman 42 filter paper than other surfaces.

Conclusions

We demonstrate the use of a simple substrate for reliable DESI‐MS analysis of cultured cells. This method has the potential to understand various interactions of cells with other external agents. The current method would help in the application of DESI‐MS for biology in general and medical sciences in particular. Copyright © 2015 John Wiley & Sons, Ltd.
Simultaneous analysis of 210 prohibited substances in human urine by ultrafast liquid chromatography/tandem mass spectrometry in doping control
Authors: Jeong Eun Sook , Kim So‐Hee , Cha Eun‐Ju , Lee Kang Mi , Kim Ho Jun , Lee Sang‐Won , Kwon Oh‐Seung , Lee Jaeick
Published: January 2015

RATIONALE

Doping analysis is a two‐step process consisting of a screening step for prohibited substances and a confirmation step to verify the presence of specific substances found during the screening. The entire process must be performed within a limited time period, but traditional screening procedures commonly employ separate analytical methods for each class of prohibited substances being screened and thus require a great deal of human resources and instrumentation. A single simple and rapid multiresidue analytical method that could accommodate multiple classes of prohibited substances would be extraordinarily useful in doping analyses.

METHODS

Urine samples were extracted via two consecutive liquid–liquid extractions at different pH values following enzymatic hydrolysis. Analyses were performed by ultrafast liquid chromatography/triple‐quadrupole mass spectrometry with polarity switching and time‐dependent selected reaction monitoring.

RESULTS

We developed a rapid multiresidue screening and confirmation method for efficient high‐throughput doping analyses. The present method was validated with regard to the limits of detection (0.01–100.0 ng/mL for screening analyses and 0.2–500.0 ng/mL for confirmation assays), matrix effects (48.9–118.9%), recovery (20.6–119.7%) and intra‐ (0.6–17.6%) and inter‐day (4.0–20.0%) precision.

CONCLUSIONS

A multiresidue analytical method was developed and validated for screening and confirming the presence of performance‐enhancing drugs. A total of 210 substances from diverse classes of prohibited substances were successfully identified with an analytical run time of 10 min. Copyright © 2015 John Wiley & Sons, Ltd.
Membrane funnel‐based spray ionization for protein/peptide analysis by Fourier transform ion cyclotron resonance mass spectrometry
Authors: Yeung Hoi Sze , Li Wan , Wang Ze , Wong Y. L. Elaine , Chen Xiangfeng , Chan T.‐W. Dominic
Published: January 2015

RATIONALE

Samples analyzed in proteomic studies by nanoelectrospray ionization (nanoESI) are extremely limited in quantity requiring careful sample handling to prevent loss upon transfer and to maintain sample concentration. To alleviate the operational process and reduce the cost of nanoESI, it is essential to develop more robust, simple and sensitive analytical variants of the process. Membrane funnel‐based spray was developed for analysis of proteins/peptides in this study.

METHODS

The membrane funnel was fabricated from thin flexible membrane by a punching method using a homemade device. The performance of the membrane funnel‐based spray was demonstrated by analyzing peptides, proteins and trypsin‐digested samples in comparison of nanoESI and the Teflon sheet based microfunnel.

RESULTS

Compared with the microfunnel, the membrane funnel can be fabricated easily by punching a thin flexible membrane using a sharp needle. Only 50 nL of sample was required for an analysis. The membrane funnel enhanced the spray sensitivity 100‐fold. A total of 5 amol of on‐spot sample loading was sufficient to provide a measurable signal on a 9.4 Tesla Fourier transform ion cyclotron resonance mass spectrometry system. High‐mass proteins (up to 66 kDa) could be analyzed using this funnel‐based spray system. Good sequence coverage was obtained for tryptic digested samples.

CONCLUSIONS

A rapid, simple and cheap membrane funnel‐based sample plate fabrication method was developed. The membrane funnel‐based spray is a promising new variant of nanoESI capable of fast and sensitive analysis of peptides/proteins with great potential that could be extended to other applications, including quantitative analysis at high throughput and imaging mass spectrometry. Copyright © 2015 John Wiley & Sons, Ltd.
Putative identification of new p‐coumaroyl glycoside flavonoids in grape by ultra‐high performance liquid chromatography/high‐resolution mass spectrometry
Authors: Panighel Annarita , De Rosso Mirko , Dalla Vedova Antonio , Flamini Riccardo
Published: January 2015

RATIONALE

Grape polyphenols are antioxidant compounds, markers in vine chemotaxonomy, and involved in color stabilization of red wines. Sugar acylation usually confers higher stability on glycoside derivatives and this effect is enhanced by an aromatic substituent such as p‐coumaric acid. Until now, only p‐coumaroyl anthocyanins have been found in grape.

METHODS

A method of 'suspect screening analysis' by ultra‐high‐performance liquid chromatography/high‐resolution mass spectrometry (UHPLC/QTOFMS) has recently been developed to study grape metabolomics. In the present study, this approach was used to identify new polyphenols in grape by accurate mass measurement, MS/MS fragmentation, and study of correlations between fragments observed and putative structures.

RESULTS

Three putative p‐coumaroyl flavonoids were identified in Raboso Piave grape extract: a dihydrokaempferide‐3‐O‐p‐coumaroylhexoside‐like flavanone, isorhamnetin‐3‐O‐p‐coumaroylglucoside, and a chrysoeriol‐p‐coumaroylhexoside‐like flavone. Accurate MS provided structural characterization of functional groups, and literature data indicates their probable position in the molecule. A fragmentation scheme is proposed for each compound.

CONCLUSIONS

Compounds were identified by overlapping various analytical methods according to recommendations in the MS‐based metabolomics literature. Stereochemistry and the definitive position of substituents in the molecule can only be confirmed by isolation and characterization or synthesis of each compound. These findings suggest addressing research of acylated polyphenol glycosides to other grape varieties. Copyright © 2015 John Wiley & Sons, Ltd.
Reintegration of the regenerated and the remaining tissues during joint regeneration in the newt Cynops pyrrhogaster
Authors: Tsutsumi Rio , Inoue Takeshi , Yamada Shigehito , Agata Kiyokazu
Published: January 2015

Urodele amphibians, such as newts, can regenerate a functional limb, including joints, after amputation at any level along the proximal−distal axis of the limb. The blastema can regenerate the limb morphology largely independently of the stump after proximal−distal identity has been established, but the remaining and regenerated tissues must be structurally reintegrated (matched in size and shape). Here we used newt joint regeneration as a model to investigate reintegration, because a functionally interlocking joint requires structural integration between its opposing skeletal elements. After forelimbs were amputated at the elbow joint, the joint was regenerated between the remaining and regenerated skeletal elements. The regenerated cartilage was thick around the amputated joint to make a reciprocally interlocking joint structure with the remaining bone. Furthermore, during regeneration, the extracellular matrix of the remaining tissues was lost, suggesting that the remaining tissues might contribute to the morphogenesis of regenerating cartilage. Our results showed that the area of the regenerated cartilage matched the area of the apposed remaining cartilage, thus contributing to formation of a functional structure.
Actuator Control for the NASA‐JSC Valkyrie Humanoid Robot: A Decoupled Dynamics Approach for Torque Control of Series Elastic Robots
Authors: Paine Nicholas , Mehling Joshua S. , Holley James , Radford Nicolaus A. , Johnson Gwendolyn , Fok Chien‐Liang , Sentis Luis
Published: January 2015

This paper discusses the actuator‐level control of Valkyrie, a new humanoid robot designed by NASA's Johnson Space Center in collaboration with several external partners. Several topics pertaining to Valkyrie's series elastic actuators are presented including control architecture, controller design, and implementation in hardware. A decentralized approach is taken in controlling Valkyrie's many series elastic degrees of freedom. By conceptually decoupling actuator dynamics from robot limb dynamics, the problem of controlling a highly complex system is simplified and the controller development process is streamlined compared to other approaches. This hierarchical control abstraction is realized by leveraging disturbance observers in the robot's joint‐level torque controllers. A novel analysis technique is applied to understand the ability of a disturbance observer to attenuate the effects of unmodeled dynamics. The performance of this control approach is demonstrated in two ways. First, torque tracking performance of a single Valkyrie actuator is characterized in terms of controllable torque resolution, tracking error, bandwidth, and power consumption. Second, tests are performed on Valkyrie's arm, a serial chain of actuators, to demonstrate the robot's ability to accurately track torques with the presented decentralized control approach.
Anticipatory Management for Instream Habitat: Application to Carneros Creek, California
Authors: Beagle J. R. , Kondolf G. M. , Adams R. M. , Marcus L.
Published: January 2015

Ecological research increasingly demonstrates that the best fish habitat is associated with complex, dynamically migrating channels. Active erosion and deposition create pools, side channels, and surfaces for recruitment of riparian vegetation, resulting in hydraulic complexity. As such, the most effective and sustainable restoration strategies restore natural processes, and in turn, create biological habitat. Nevertheless, there exists a social–cultural preference for stable channels. Landowners are often unhappy with eroding banks and, more broadly, are uncomfortable with ‘messy’ ecosystems and the erosion, deposition, and channel migration that are essential components of the dynamic channels that provide the greatest floodplain biodiversity. Episodic bank erosion and failure are often treated with emergency response measures, such as riprap and bank hardening. This often results in simplified channels with minimized instream habitat. Here, we propose an alternative management approach for streams with cohesive banks, and where active erosion is concentrated in ‘hot spots’ that are roughly predictable based on geomorphic analysis. We term the approach anticipatory management and present an application of the approach to Carneros Creek, an incised tributary to the Napa River. We contrast the likely habitat values and agricultural land loss of the anticipatory management approach to: (i) a conventional bank stabilization project proposed for the creek, and (ii) a series of uniform setbacks. Copyright © 2015 John Wiley & Sons, Ltd.