bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of electrical polarization and composition of biphasic calcium phosphates on early stage osteoblast interactions
Authors: Tarafder Solaiman , Bodhak Subhadip , Bandyopadhyay Amit , Bose Susmita
Published: March 2011

In spite of having excellent biocompatibility and osteogenic property of hydroxyapatite (HAp) and β‐tricalcium phosphate (β‐TCP), concerns have been raised regarding their degradation kinetics. Complete in vivo degradation of HAp takes years because of its slow degradation rate, and fast degradation rate of β‐TCP limits its application. Biphasic calcium phosphates (BCPs) composed of both HAp and β‐TCP have controlled degradation to some extent. Here, we have prepared three different BCPs composed of β‐TCP and HAp. These BCP composites are successfully electrically polarized to generate surfaces with positive (P‐poled) and negative (N‐poled) charges. Thermally stimulated depolarized current measurement (TSDC) exhibits increased stored charge density with the increase in HAp percentage in the composites. Our study focuses on understanding the effect of composition variation as well as electrical polarization of these composites on early stage osteoblast‐cell adhesion, proliferation, and extracellular matrix (ECM) formation capability. No matter what the composition is, N‐poled (Negatively poled) surfaces show early stage osteoblast‐cell adhesion, proliferation, and ECM formation when compared with U‐poled (unpoled) and P‐poled (positively poled) surfaces. Irrespective of the surface charge, an improved cell‐material interactions are observed as the percentage of HAp content in the composites is increased. These electrically polarized BCP composites can have potential use in the area of orthopedics and dentistry. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
Early interactions between leukocytes and three different potentially bioactive titanium surface modifications
Authors: Arvidsson Anna , Malmberg Per , Kjellin Per , Currie Fredrik , Arvidsson Martin , Franke Stenport Victoria
Published: March 2011

The aim of the present study was to compare the early interactions between leukocytes and three different surface modifications, suggested as bioactive. Blasted titanium discs were modified by alkali and heat treatment, sodium fluoride treatment, or hydroxyapatite coating. A number of these discs were also immersed in simulated body fluid (SBF) for a week, a treatment which yielded high levels of calcium and phosphate on each surface type. The specimens were exposed for human venous blood for 32 minutes and the respiratory burst response was measured in terms of reactive oxygen species with a luminometer, and coverage of viable cells with a fluorescence microscope after staining steps. The topography, morphology, and chemistry of the surfaces were evaluated with optical interferometry and scanning electron microscopy/energy dispersive X‐ray analysis (SEM/EDX). A high respiratory burst response was found for HA coated titanium in comparison with the other surface groups (p < 0.0005). The SBF immersion resulted in an increased respiratory burst response (p < 0.0005) and removed statistically significant differences between the surface groups. Thus, the results in the present study indicate that different titanium surface modifications influence the early inflammatory response differently, and that calcium phosphate compounds increase the inflammatory response. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
Hyperglycemia induces apoptosis via CB1 activation through the decrease of FAAH 1 in retianl pigment epithelial cells
Authors: Lim Seul Ki , Park Min Jung , Lim Jae Cheong , Kim Jong Choon , Han Ho Jae , Kim Gye‐Yeop , Cravatt Benjamin F. , Woo Chang Hoon , Ma Seung Jin , Yoon Kyung Cheol , Park Soo Hyun
Published: March 2011

Fatty acid amide hydrolase (FAAH), the enzyme responsible for the degradation of the main endocannabinoid, anandamide, and related fatty acid amides, has emerged as a regulator of endocannabinoid signaling. Retinal pigment epithelial (RPE) cells are believed to be important cells in the pathogenesis of diabetic retinopathy. However, the pathophysiology of FAAH in diabetic retinopathy has not been determined. Thus, we examined the effect of high glucose (HG) on the expression of FAAH and CB1R in the ARPE‐19 human RPE cells. We found that HG downregulated the expression of FAAH 1 mRNA and protein in ARPE‐19 cells. In contrast, it upregulated the expression of CB1R mRNA and protein. HG‐induced internalization of CB1R in HEK 293 cells and ARPE‐19 cells was blocked by overexpression of FAAH 1 and treatment with the CB1R blocker, AM 251. HG‐induced generation of reactive oxygen species and lipid peroxide formation were blocked by the overexpression of FAAH 1. FAAH 1 overexpression also blocked HG‐induced expression of CB1R in the cytosolic fraction. We also investigated whether the overexpression of FAAH 1 protected against HG‐induced apoptosis. High glucose increased the Bax/Bcl‐2 ratio and levels of cleaved PARP, cleaved caspase‐9 and caspase‐3, and reduced cell viability. HG‐induced apoptotic effects were reduced by the overexpression of FAAH 1, treatment with the CB1R‐specific antagonist AM 251 and CB1R siRNA transfection. In conclusion, HG‐induced apoptosis in ARPE‐19 cells by inducing CB1R expression through the downregulation of FAAH 1 expression. Our results provide evidence that CB1R blockade through the recovery of FAAH 1 expression may be a potential anti‐diabetic therapy for the treatment of diabetic retinopathy. J. Cell. Physiol. 227: 569–577, 2012. © 2011 Wiley Periodicals, Inc.
Cross species fertilization and development investigated by cat sperm injection into mouse oocytes
Authors: Xu Yong‐Nan , Cui Xiang‐Shun , Sun Shao‐Chen , Jin Yong‐Xun , Kim Nam‐Hyung
Published: March 2011

The use of intracytoplasmic sperm injection (ICSI) in model animals is a powerful approach for the study of species‐specific fertilization processes and multiploidy embryogenesis. In this study, we examined the fertilization process in mouse oocytes following injection of a single mouse or cat sperm, two mouse spermatozoa or mouse and cat spermatozoa. These treatments did not affect histone H3K9 acetylation or methylation, although the pattern of DNA methylation differed following the injection of cat sperm. Immunocytochemical staining revealed that sperm chromatin was normally incorporated with female mouse chromatin following any of the four injection scenarios. Furthermore, metaphase was successfully entered to reach a normal two‐cell stage, and cell division could even persist to produce blastocyst stage embryos. In addition, both mouse and catPou5landNanogmRNA were expressed in the hybrid embryos. These results suggest that, although epigenetic modification of DNA is affected by the sperm injection treatment, fertilization and cleavage occur in a non‐species‐specific manner. In addition, despite abnormal division of the chromosomes, intra‐ and inter‐species ICSI produced embryos that could develop into blastocysts.J. Exp. Zool. 315:349–357, 2011. © 2011 Wiley‐Liss, Inc.
State‐business relations and pro‐poor growth in South Africa
Authors: Seekings Jeremy , Nattrass Nicoli
Published: March 2011

By comparison with most African countries, post‐apartheid South Africa appears to be characterised by growth‐oriented cooperation between state and business. Economic growth has remained weak, however, and income poverty persists as the economy continues down an inegalitarian growth path that fails to reduce unemployment and thus has little effect on poverty. This paper argues that the appearance of close state‐business relations is misleading: selectively pro‐market public policies have not reflected a pro‐business orientation on the part of the state. The governing African National Congress concurred with established business on the need for increased productivity and selective state interventions in a mixed economy. But most of the political elite overestimated the commandist powers of the state in the short‐term, viewed established South African business with deep suspicion if not hostility, and was unwilling to deliberate or negotiate on distributional issues in either formal bilateral or corporatist institutions, or even informally. The state sought to discipline and transform business, not work with it. Unable to sustain an active growth coalition, a pro‐poor, developmental coalition was far out of reach. The politics of the governing party precluded substantive concessions on labour market regulation and pushed it towards ever more interventionist ‘black economic empowerment’ policies. The result was that economic growth remained modest, and of little benefit to the poor. Copyright © 2011 John Wiley & Sons, Ltd.
How interest groups lobby to influence budget outcomes in Zambia
Authors: Bwalya Samuel M. , Phiri Ezekiel , Mpembamoto Kelvin
Published: March 2011

This paper examines the nature of state–business relations and how interest groups utilise the budget process to lobby for tax and expenditure policies in Zambia, using information compiled from budget proposals interest groups submit towards the budget and lobbying activity data published in the daily newspapers between 2006 and 2008. The data shows a significant increase in interest groups formed especially in the civil society segmented and improvements in state–business relations, although not formalised and institutionalised, since political liberalisation in 1991. Analysis of lobbying data indicates that interest groups utilise the formal budget processes and informal policy networks such as the media to lobby unilaterally and collectively for favourable tax and expenditure policies. Tax proposals submitted through government departments had a greater chance of being adopted in the budget as bureaucrats assisted to shepherd them through the budget process. Copyright © 2011 John Wiley & Sons, Ltd.
Synthesis of [2H5]‐ebastine fumarate and [2H5]‐hydroxyebastine
Authors: Yu Zhoujie , Wang Wei , Chen Liqin
Published: March 2011

This study describes the synthesis of deuterium‐labelled ebastine fumarate and its deuterium‐labelled metabolite hydroxyebastine. The synthesis of the two desired compounds both used [2H5]‐bromodiphenylmethane as deuterium‐labelled reagent, which was synthesized beforehand in three steps. [2H5]‐ebastine was synthesized in further three steps with a 27% overall yield and [2H5]‐hydroxyebastine was synthesized in further seven steps with a 13% overall yield. Copyright © 2011 John Wiley & Sons, Ltd.
Electron‐bombardment matrix isolation and PEPICO studies as complementary techniques in ion chemistry: an FTIR study of the decomposition of the vinyl fluoride cation
Authors: Thompson Matthew G. K. , Linford Bryan D. , Parnis J. Mark
Published: March 2011

FTIR spectra have been obtained for matrices formed following electron bombardment of gas mixtures containing varying amounts of vinyl fluoride (VF) in Ar (1:400 to 1:25 600; VF/Ar). The major matrix‐isolated products are a π‐complex of HF/C2H2, fluoroacetylene (HC≡CF) and two isomers of C2H2F•. These products correspond well with the products of photoionization of VF near 15.8 eV. These observations support the dominant mechanism of ionization in the EB‐MI environment as charge transfer of the substrate molecule to Ar•+. Some differences are noted between the observed EB‐MI products and the results from PEPICO studies, primarily in that the EB‐MI products are observed as neutralized forms. The close correlation in EB‐MI and photoionization results allows the EB‐MI technique to be utilized as an ion structural analysis tool in complement to PEPICO studies, and allows the use of PEPICO studies to help predict and elucidate high‐pressure chemistry mechanisms through EB‐MI studies. The differences in the EB‐MI results and ions observed using the PEPICO technique are rationalized in terms of the differences in the experimental techniques. Using VF as the test system, reagent partial pressure conditions that best complement PEPICO studies are determined. Although the major results are observed for all VF partial pressures, dilute samples give rise to further ionization of the primary products, and more concentrated samples give rise to radical—radical reaction chemistry. As a result, a nominal range of 1:3200 (VF/Ar) is demonstrated to provide the best correlation with the gas‐phase PEPICO measurements. Copyright © 2011 John Wiley & Sons, Ltd.
Ab initio quantum chemical study on the mechanism of exceptional behavior of lysine for ion yields in MALDI—role of vibrational entropic contribution in thermally averaged proton affinities
Authors: Hatakeyama Makoto , Tachikawa Masanori
Published: March 2011

To elucidate the mechanism of the exceptional behavior of lysine for the ionization (protonation) yields in matrix‐assisted laser desorption/ionization (MALDI) observed by Nishikaze and Takayama [Rapid Commun. Mass Spectrom. 2006, 20, 376], the temperature dependences of proton affinity (PA) and gas phase basicity for 20 amino acids are theoretically analyzed with correlated ab initio molecular orbital method under ideal gas condition. We have found that two different conformations, the linear structure with elongation of the side chain and the folded one having intramolecular hydrogen bonding, play important roles for the exceptional behavior of lysine. At low temperatures of around 298 K, the most stable conformation of the protonated lysine is the folded structure due to the formation of intramolecular hydrogen bonding. Meanwhile, at high temperatures, the Gibbs free energy of linear structure of protonated lysine becomes lower than that of the folded one because of the increment of vibrational entropic contribution. To explicitly take account of the contribution of the free energies, we have proposed the effective PA values thermally averaged using the ratio of Boltzmann distributions for two conformations. Since the effective PA value for lysine drastically decreases as the temperature increases above 1000 K, the linear correlation is clearly obtained between our effective PA values at high temperature and the ion yields in MALDI. Copyright © 2011 John Wiley & Sons, Ltd.
Comparison of APPI, APCI and ESI for the LC‐MS/MS analysis of bezafibrate, cyclophosphamide, enalapril, methotrexate and orlistat in municipal wastewater
Authors: Garcia‐Ac Araceli , Segura Pedro A. , Viglino Liza , Gagnon Christian , Sauvé Sébastien
Published: March 2011

The applicability of three different ionization techniques: atmospheric pressure photoionization (APPI), atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI) was tested for the liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) analysis of five target pharmaceuticals (cyclophosphamide, methotrexate, bezafibrate, enalapril and orlistat) in wastewater samples. Performance was compared both by flow injection analysis (FIA) and on‐column analysis in deionized water and wastewater samples. A column switching technique for the on‐line extraction and analysis of water samples was used. For both FIA and on‐column analysis, signal intensity and signal‐to‐noise (S/N) ratio of the target analytes in the three sources were studied. Limits of detection and matrix effects during the analysis of wastewater samples were also investigated. ESI generated significantly larger peak areas and higher S/N ratios than APCI and APPI in FIA and in on‐column analysis. ESI was proved to be the most suitable ionization method as it enabled the detection of the five target compounds, whereas APCI and APPI ionized only four compounds. Copyright © 2011 John Wiley & Sons, Ltd.
MALDI‐TOF and MALDI‐FTICR imaging mass spectrometry of methamphetamine incorporated into hair
Authors: Miki Akihiro , Katagi Munehiro , Kamata Tooru , Zaitsu Kei , Tatsuno Michiaki , Nakanishi Toyofumi , Tsuchihashi Hitoshi , Takubo Takayuki , Suzuki Koichi
Published: March 2011

A new approach is described for imaging mass spectrometry (IMS) of methamphetamine (MA) incorporated into human hair using matrix‐assisted laser desorption/ionization (MALDI)‐time‐of‐flight (TOF) and MALDI‐Fourier transform ion cyclotron resonance (FTICR). A longitudinal section of a lengthwise manually‐cut single human hair shaft from a chronic MA user was directly analyzed by MALDI‐TOF‐IMS after deposited with α‐Cyano‐4‐hydroxycinnamic acid matrix. A barcode‐like image, which was most probably generated with repeated intakes of MA, was for the first time obtained by monitoring MA‐specific product ion in the selected reaction monitoring mode. Laser beam scan lengthwise‐cut hair shafts gave only poor mass spectra of MA, probably due to the loss of MA and/or the thermal denaturation of hair. The identity of MA detected in hair was further confirmed by MALDI‐FTICR mass spectrometry. A combination with ultra‐high resolution mass spectrometry by FTICR provided indisputable identification of MA. The MALDI‐FTICR‐IMS of another hair shaft from the same MA user also provided a barcode‐like image by monitoring the protonated molecule of MA with ultra‐high resolution. The two barcode‐like images exhibited a close resemblance. Thus, MALDI‐IMS can offer a new perspective: ‘imaging hair analyses for drugs’. Copyright © 2011 John Wiley & Sons, Ltd.
Mass spectrometric characterization of isomeric terpenoic acids from the oxidation of α‐pinene, β‐pinene, d‐limonene, and Δ3‐carene in fine forest aerosol
Authors: Yasmeen Farhat , Szmigielski Rafal , Vermeylen Reinhilde , Gómez‐González Yadian , Surratt Jason D. , Chan Arthur W. H. , Seinfeld John H. , Maenhaut Willy , Claeys Magda
Published: March 2011

In this study, we present liquid chromatographic and mass spectral data for predominant terpenoic acids formed through oxidation of α‐pinene, β‐pinene, d‐limonene, and Δ3‐carene that occur in fine forest aerosol from K‐puszta, Hungary, a rural site with coniferous vegetation. Characterization of these secondary organic aerosol tracers in fine ambient aerosol is important because it allows one to gain information on monoterpene precursors and source processes such as oxidation and aging processes. The mass spectral data were obtained using electrospray ionization in the negative ion mode, accurate mass measurements, and linear ion trap tandem mass spectrometric experiments. Emphasis is given to the mass spectrometric differentiation of isobaric terpenoic acids, such as, e.g. the molecular weight (MW) 186 terpenoic acids, cis‐pinic, cis‐caric, homoterpenylic, ketolimononic, and limonic acids. Other targeted isobaric terpenoic acids are the MW 184 terpenoic acids, cis‐pinonic and cis‐caronic acids, and the MW 204 tricarboxylic acids, 3‐methyl‐1,2,3‐butanetricarboxylic and 3‐carboxyheptanedioic acids. Fragmentation pathways are proposed to provide a rational explanation for the observed isomeric differences and/or to support the suggested tentative structures. For the completeness of the data set, data obtained for recently reported lactone‐containing terpenoic acids (i.e. terpenylic and terebic acids), related or isobaric compounds (i.e. norpinic acid, diaterpenylic acid acetate, and unknown MW 188 compounds) are also included, the rationale being that other groups working on this topic could use this data compilation as a reference. Copyright © 2011 John Wiley & Sons, Ltd.
Measurements and attenuation of erythemal radiation in Central Spain
Authors: Miguel A. , Bilbao J. , Román R. , Mateos D.
Published: March 2011

Biologically active ultraviolet (UVER, 280–400 nm) and global (300–3000 nm) solar irradiances have been recorded and analysed in a rural area in Valladolid (Spain) for a period of 49 months between June 2002 and December 2008. UVER daily measurements follow the pattern of the solar elevation angle and maximum hourly average irradiances occur in July, 0.20 Wm−2 and minimum, 0.03 Wm−2, in December at noon; the total accumulated UVER along a year reaches 1470 kJm−2. The temporal evolution of the erythemal ultraviolet radiation and its distribution under different sky conditions have been studied, being 25% clear, 57% partly cloudy and 18% overcast days. The most representative statistical characteristics of the hourly and daily UVER data have been evaluated for different sky conditions and the fundamental indices show symmetry with respect to solar noon. Maximum values may be considered as representative of the UVER characteristics in the area, whereas the minimum values are not significant, mainly during summertime. The UVER records show quite stable values in the analysed period, particularly along the months of July. The isoline‐set of the first four moment distribution of the hourly UVER values has been plotted and the relative gradients are shown. The results are compared with the values obtained in other stations. The UVER cloud attenuation through the atmosphere shows that the transmitted percentage increases from winter to summer and a maximum value of 10% was achieved in July and a minimum of 30% in winter and spring. Copyright © 2011 Royal Meteorological Society
Tropical systems from the southwest Indian Ocean making landfall over the Limpopo River Basin, southern Africa: a historical perspective
Authors: Malherbe J. , Engelbrecht F.A. , Landman W.A. , Engelbrecht C.J.
Published: March 2011

The study provides perspective on the contribution of landfalling tropical systems (cyclones, depressions, storms and lows) from the southwest Indian Ocean (SWIO) towards rainfall over the eastern interior of southern Africa, over the period 1948–2008. Although these systems contribute to < 10% of the annual rainfall occurring over the region, their relative contribution to local and widespread heavy rainfall events is shown to be highly significant. About 50% of widespread heavy rainfall events over northeastern South Africa are caused by landfalling tropical systems. Fourier analysis performed on the time series of rainfall occurring over northeastern South Africa in association with these systems reveals the existence of a quasi‐18‐year cycle. The cycle coincides with the well‐known quasi‐18‐year Dyer–Tyson cycle in rainfall over the summer rainfall region of South Africa. These results suggest that atmospheric and surface conditions leading to wet phases of the Dyer–Tyson cycle also favour the landfall and subsequent westward movement of tropical systems from the SWIO over southern Africa—and their eventual contribution to rainfall over northeastern South Africa and southern Zimbabwe. Copyright © 2011 Royal Meteorological Society
Geochemical assessment, distribution, and dynamics of trace elements in urban agricultural soils under long‐term wastewater irrigation in Kano, northern Nigeria
Authors: Abdu Nafiu , Agbenin John O. , Buerkert Andreas
Published: March 2011

A study was conducted to evaluate the distribution and origin of trace elements (Ti, Fe, Nb, Pb, Rb, Sr, Y, and Zr) in five representative long‐term wastewater‐irrigated urban vegetable gardens of Kano, Nigeria. Surface‐soil concentrations (0–15 cm) of Ti (4600–14 300 mg kg–1), Fe (4000–31 800 mg kg–1), Pb (96–355 mg kg–1), and Y (33–98 mg kg–1) were high compared to mean concentrations in comparable soils elsewhere. However, soil‐pollution assessment yielded no evidence of anthropogenic input of the trace elements studied. Indices such as the enrichment factor, the contamination factor, and the geoaccumulation index (Igeo) revealed little to no contamination with trace elements. The Igeo calculated for these metals varied across locations between 0.00 and 0.12 with Nb having the highest Igeo value. Similarly, the contamination factor was low for all metals with the exception of Fe reaching a contamination factor of 4.2 at one location. Geochemical‐balance evaluations showed depletion of all trace elements except for Fe which was 176% higher than in a natural uncultivated and unirrigated reference soil. Correlation and factor analyses showed that all determined trace elements likely originated from the same natural sources, which probably are the soil parent material and atmospheric depositions.
A new splash cup to measure the kinetic energy of rainfall
Authors: Scholten Thomas , Geißler Christian , Goc Jacek , Kühn Peter , Wiegand Christoph
Published: March 2011

Splash cups have long been successfully used for both the quantification of kinetic energy of rainfall and the detachability of soil particles by rainfall impact, the so‐called “splash erosion”. Measurements of kinetic energy, however, have been difficult to operate in the field especially in remote areas, on steep slopes, and in forests since boundary conditions need to be controlled precisely. This paper introduces a new splash cup based on Ellison's archetype that reliably and accurately measures kinetic energy as a function of sand loss under a large variety of conditions. The Tübingen splash cup (T splash cup) is relatively easy to operate under harsh field conditions, and it can be used in experimental designs with a large number of plots and replications at reasonably low costs. The cup is constructed from plastic laboratory flasks and plastic pipes from water‐supply equipments. The unit sand is held by a removable carrier system that can easily be replaced in the field. The splash cups have been calibrated in combination with a laser distrometer using a linear regression function with r2 = 0.98. They measure kinetic energy over a wide range of rainfall intensities from 0.6 to 40 L m–2 h–1. Kinetic energy per area varies between 10 and 250 J m–2. Two years of field test measurements in a subtropical forest ecosystem in China proved the reliability, durability, and usability of our new splash cups and allowed detecting differences in kinetic energy between different tree species and biodiversity levels.
Phase‐shaping strategies for coherent anti‐Stokes Raman scattering
Authors: van Rhijn A. C. W. , Jurna M. , Jafarpour A. , Herek J. L. , Offerhaus H. L.
Published: March 2011

The identification of large molecules in complex environments requires probing of multiple vibrational resonances rather than a single resonance. Phase‐shaping the excitation pulses allows the coherent mixing of several resonances so that the presence of molecules can be inferred directly from the integrated output pulse energy. This avoids the need for the collection of spectra or multiple measurements. This article describes a particular implementation for coherent anti‐Stokes Raman scattering microscopy that uses a broadband pump and probe field in combination with a narrowband Stokes field. We numerically study the possibilities of optimizing selectivity, specificity, and sensitivity by precalculating pulse shapes using an evolutionary algorithm. Copyright © 2011 John Wiley & Sons, Ltd.
Base‐induced transient isotachophoretic stacking of acidic drugs in capillary zone electrophoresis
Authors: Quirino Joselito P.
Published: March 2011

Online sample concentration of acidic drugs by transient isotachophoresis (t‐ITP) with the injection of a base is described in capillary zone electrophoresis (CZE). A positively coated capillary was conditioned with background electrolyte (ammonium acetate at pH 6). A long plug of sample solution (S) prepared in ammonium acetate was then hydrodynamically injected followed by the base (tetrapropylammonium hydroxide). A negative voltage was applied and caused the hydroxide ions from the base to penetrate the S zone and created a pH junction that swept through the S zone. The analytes stack at the junction where the mechanism of focusing was transient ITP with the acetate and hydroxide ions as leading and terminating ions, respectively. The concentrated analytes separated in co‐EOF CZE once the hydroxide was exhausted. The base stacking strategy was tested using hypolipidemic, nonsteroidal anti‐inflammatory, and diuretic drugs, and afforded 19–37 improvements in peak height.
One‐step separation and purification of hydrolysable tannins from Geranium wilfordii Maxim by adsorption chromatography on cross‐linked 12% agarose gel
Authors: Liu Dan , Ma Yan , Wang Ye , Su Zhiguo , Gu Ming , Janson Jan‐Christer
Published: March 2011

The hydrolysable tannins corilagin and geraniin, the major active components of the traditional Chinese medicine Geranium wilfordii Maxim, have been separated and purified from crude extracts in one step by adsorption chromatography on cross‐linked 12% agarose gel (Superose 12 10/300 GL). The separation was achieved by gradient elution using mobile phase A composed of 5% ethanol and 5% acetic acid and mobile phase B composed of 30% ethanol and 30% acetic acid. The gradients were composed as follows: 0–240 mL, 0–25% B; 240–480 mL, 25–40% B; after 480 mL, 100% B. The purities of the collected corilagin and geraniin were 92.4 and 87.2%, and the corresponding yields were 88.0 and 76.8%, respectively.
Traumatic bereavement, acute dissociation, and posttraumatic stress: 14 years after the MS Estonia disaster
Authors: Arnberg Filip K. , Eriksson Nils‐Gustaf , Hultman Christina M. , Lundin Tom
Published: March 2011

This prospective longitudinal study aimed to examine posttraumatic stress in survivors 14 years after a ferry disaster, and estimate short‐ and long‐term changes in stress associated with traumatic bereavement and acute dissociation. There were 852 people who perished in the disaster, 137 survived. The 51 Swedish survivors were surveyed with the Impact of Event Scale–Revised (IES‐R) at 3 months, 1, 3, and 14 years (response rates 82%, 65%, 51%, and 69%). Symptoms decreased from 3 months to 1 year; no change was found thereafter. After 14 years, 27% reported significant symptoms. Traumatic bereavement, but not acute dissociation, was associated with long‐term symptom elevation. Chronic posttraumatic stress can persist in a minority of survivors, and traumatic bereavement appears to hinder recovery.
Mass spectrometry of atmospheric aerosols—Recent developments and applications. Part I: Off‐line mass spectrometry techniques
Authors: Pratt Kerri A. , Prather Kimberly A.
Published: March 2011

Many of the significant advances in our understanding of atmospheric particles can be attributed to the application of mass spectrometry. Mass spectrometry provides high sensitivity with a fast response time to probe chemically complex particles. This review focuses on recent developments and applications in the field of mass spectrometry of atmospheric aerosols. In Part I of this two‐part review, we concentrate on off‐line mass spectrometry techniques, which require sample collection on filters but can provide detailed molecular speciation. In particular, off‐line mass spectrometry techniques utilizing tandem mass spectrometry experiments and high resolution mass analyzers provide improved insight into secondary organic aerosol formation and heterogeneous reaction pathways through detailed structural elucidation at the molecular level. © 2011 Wiley Periodicals, Inc., Mass Spec Rev 31:1–16, 2012
Studying the interaction between dislocations and precipitates in a Ni‐base superalloy in the VHCF regime
Authors: Stöcker C. , Zimmermann M. , Christ H.‐J.
Published: March 2011

In den letzten Jahren hat sich ein zunehmendes wissenschaftliches und technisches Interesse an dem Ermüdungsverhalten von Konstruktionswerkstoffen bei sehr hohen Lastspielzahlen (VHCF) entwickelt. Gerade im klassischen Einsatzgebiet von Nickelbasis‐Superlegierungen, dem Turbinenbau, ist von Lebensdauerforderungen auszugehen, die bis in den sogenannten Very High Cycle Fatigue (VHCF)‐Bereich (N > 107) hineinreichen. Am Beispiel der Nickelbasis‐Superlegierung Nimonic 80A wurde daher das Ermüdungsverhalten im VHCF‐Bereich hinsichtlich der Korrelation von Versetzungsgleitverhalten und Ausscheidungszustand (maximal ausscheidungsgehärtet sowie überaltert) untersucht. Überraschenderweise ist die ertragbare Spannungsamplitude für den überalterten Zustand im VHCF‐Bereich gegenüber dem maximal ausscheidungsgehärteten Zustand höher und damit weder aus der statischen Festigkeit noch aus dem klassischen LCF/HCF‐Ermüdungsverhalten ableitbar. Die mittels Raster‐ und Transmissionselektronenmikroskopie beobachteten mikrostrukturellen Vorgänge (z.B. Gleitbandbildung an Oberflächenkörnern und Wechselwirkung Versetzungen/Ausscheidungen) liefern hierfür erste Erklärungsansätze. Eine Gegenüberstellung von Wechselverformungskurven für Spannungsamplituden im Kurzzeitfestigkeits‐ wie auch im VHCF‐Bereich verdeutlichen die Diskrepanz zwischen globalem und lokalem plastischen Verformungsanteil und den Einfluss auf die Schädigungsentwicklung des jeweiligen Lastspielzahlbereichs.
Development of UV/VIS spectrometric methodology for corrosion inhibitor residuals monitoring in oilfield brine
Authors: Doležal D. , Bolanca T. , Stefanović Š. C.
Published: March 2011

This work focuses on the development of UV/VIS spectrometric methodology for corrosion inhibitor residuals monitoring in oilfield brine. There is no standard method for the determination of corrosion inhibitor concentration in oilfield brine. Developed methodology can be described as a rugged and simple alternative to the sophisticate separation techniques and can be easily applied in the field. The applicability of the method is demonstrated by the analyses of three commercial products. The extensive performance characteristics test, in combination with study and quantification of measurement uncertainty, shows that developed method meets all required criteria and can be directly applied for routine monitoring purposes within quality management system conditions. Therefore, this new method was accredited by the respectable accreditation agency. Valid and reliable determination of corrosion inhibitor residuals in oilfield brine is important in order to ensure effective corrosion protection of metal construction.
Wear behavior of HPPMS deposited (Ti,Al,Si)N coating under impact loading
Authors: Bobzin K. , Bagcivan N. , Ewering M. , Theiß S.
Published: March 2011

Over the last decade the interest in High Power Pulse Magnetron Sputtering (HPPMS) and High impulse Magnetron Sputtering (HiPIMS) has undergone a considerable increase. This is mainly due to the fact that several researchers have shown that in these processes a distinct increase of the ionization of deposition species is observable. However, there is only little known about the performance of these films with regard to applications. Recently Hovsepian et al. [1] and Bobzin et al. [2] presented cutting results of different films. Both authors show that films deposited using HPPMS or HiPIMS outperform state‐of‐the‐art coatings. Depending on the cutting process, besides hardness and adhesion also excellent impact behavior is required. Therefore this work deals with the impact behavior of (Ti,Al,Si)N which was deposited using HPPMS for the application in interrupted cutting process. The impact behavior of HPPMS coating under normal and tangential loads is analyzed. During impact tests number of impacts, loads and inclination angle of the samples with regard to the load direction are varied. (Ti,Al,Si)N shows an excellent endurance even at very high loads causing Hertzian stresses in the range of 10–13 GPa. At an inclination angle of 10° and an impact load of 100 N, which corresponds to app. 10 GPa initial Hertzian stress, no damage was observed after 800×103 impacts.
Compact and broadband tunable hybrid ring coupler using synthetic left‐ and right‐handed transmission lines
Authors: Kim Hongjoon
Published: March 2011

In this letter, we present a frequency tunable hybrid ring coupler based on the concepts of a synthetic left‐ and right‐handed transmission line.The proposed ring coupler makes use of lumped inductor‐capacitor (LC) elements to greatly reduce the circuit size; meanwhile, the frequency responses of the coupler can be tuned by direct current (DC) bias voltages. The fabricated hybrid ring coupler shows a wideband performance with an insertion loss of less than 2.5 dB from 1.7 to 3.3 GHz. For this frequency band, the isolation is maintained at more than 24 dB. When the circuit is excited to get a pair of differential signal, less than ±5° phase error is observed for the whole frequency range. This hybrid has a 78% size reduction compared to the conventional ones and achieved a 64% of fractional bandwidth at 2.5 GHz. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1379–1382, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25959
On‐board small‐size printed LTE/WWAN mobile handset antenna closely integrated with system ground plane
Authors: Chu Fang‐Hsien , Wong Kin‐Lu
Published: March 2011

An on‐board uniplanar printed mobile handset antenna with a small size of 15 × 30 mm2 for 8‐band long term evolution/wireless wide area network (LTE/WWAN) (698–960/1710–2690 MHz) operation is presented.The antenna is a spiral monopole coupled with a long parasitic shorted strip. The spiral monopole has a length of 78 mm (about 0.25 wavelength at 950 MHz), while the shorted strip capacitively excited by the spiral monopole has a length of 125 mm (close to 0.25 wavelength at 700 MHz). The spiral monopole is encircled by the shorted strip so that the antenna has a compact configuration to fit in a small no‐ground portion at the corner of the bottom edge of the main circuit board in the mobile handset. In addition, the antenna is closely integrated with the system ground plane on the main circuit board and is spaced by a small distance of 0.5 mm to the nearby system ground plane. This leads to compact integration of the on‐board LTE/WWAN printed antenna on the main circuit board of the mobile handset. Results of the proposed antenna including its specific absorption rate and hearing aid compatibility behavior are presented and discussed. The antenna is about the smallest for the on‐board all‐printing LTE/WWAN handset antennas that have been reported for the present. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1336–1343, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25961
A highly efficient and linear inverted Doherty power amplifier with unsymmetrical delay path
Authors: Kam Sang‐Ho , Lee Mun‐Woo , Lee Yong‐Sub , Jeong Yoon‐Ha
Published: March 2011

A highly efficient and linear inverted Doherty power amplifier (IDPA) with unsymmetrical delay path is presented. To compensate the phase difference between carrier and peaking cells, an additional offset line is inserted at the input path of the carrier cell. For verification, the IDPA with unsymmetrical delay path is implemented using two 50‐W Si LDMOSFETs and tested using a continuous wave (CW) and a one‐carrier wideband code division multiple access (WCDMA) signals at 2.6 GHz. From the measured results, the proposed IDPA shows not only an increase in the gain and the power‐added efficiency, but also superior adjacent channel leakage ratios improvement. After the digital predistortion linearization, the proposed IDPA shows better improved linearity than conventional IDPA, and also meet the linearity requirement of the WCDMA signal without decreasing efficiency. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1302–1305, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25962
Design of a new UWB‐integrated antenna filter with a rejected WLAN band at 5.8 GHz
Authors: Djaiz A. , Nedil M. , Habib M.A. , Denidni T. A.
Published: March 2011

In this article, a new ultra‐wideband (UWB)‐integrated antenna‐filter notched at HiPerLAN 5.8 GHz frequency is presented. This antenna filter system is composed of a rectangular slot fed with a microstrip rectangular patch by coupling effect and cascaded with an UWB interdigital hairpin resonator filter. The proposed components, antenna and filter, are matched with 50 Ω, to allow an easier connection, with no need to add additional matching circuit. To improve the selectivity of the antenna filter system, two wide sections of microstrip line was inserted between the input/output feed lines and the interdigital hairpin resonators of the UWB filter. To validate the proposed concept, a prototype was fabricated and tested. The experimental results are presented and discussed. The obtained results show a good agreement between experimental and full‐wave electromagnetic (EM) simulation results. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1298–1302, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25963
Fiber core size determination from power measurements in a fiber‐to‐fiber design
Authors: Golnabi H.
Published: March 2011

Fiber core size determination from power transmission modulation for different fibers is reported.Three different fibers are tested and power variations of lateral displacement of the second fiber are obtained (lamp, red LED). From the averaged bandwidths of the response curves the core diameter of each fiber is determined. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1225–1229, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25967
Compact low‐pass filters using novel ϕ‐shape defected ground structure
Authors: La Dong‐sheng , Lu Ying‐hua , Zhang Jin‐ling
Published: March 2011

A novel ϕ‐shape defected ground structure (DGS) is proposed in this article.Low‐pass filters are designed using the ϕ‐shape DGS with H shape open stubs line. Single, two‐cascaded and three‐cascaded ϕ‐shape DGS low‐pass filters are designed, simulated, fabricated, and measured. The resonant characteristic of the two‐cascaded ϕ‐shape DGS low‐pass filter shows its advantages of compact size, high selectivity, low insertion loss, and excellent passband performance. The frequency response of the three‐cascaded ϕ‐shape DGS low‐pass filter presents the advantages of compact size, high selectivity, low insertion loss, better passband performance, and high outband suppression. The measured results show a good agreement with the simulated results. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1456–1459, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25968
Investigation on stimulated Brillouin scattering effect in Photonic crystal fiber
Authors: Ahmad H. , Parvizi R. , Ali N. M. , Shahabuddin N. S. , Arof H. , Harun S. W.
Published: March 2011

A single wavelength ring Brillouin fiber laser (BFL) is demonstrated using a piece of Photonic crystal fiber (PCF) as a gain medium.The BFL has a peak power of more than 0 dBm, a side mode suppression ratio of more than 26 dB and a BP threshold power of approximately 9.4 dBm with 100‐m long PCF. The threshold of the BFL increases with the use of shorter PCFs. The Brillouin gain coefficient was calculated to be 3.2 × 10−11 m/W using the measured BP threshold power. A figure of merit of the proposed BFL is calculated to be nearly 76 times larger than the best silica‐based configurations reported to date. The induced time delay is approximately 0.056 (ns/mW/m), which is suitable for slow light‐based applications. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1450–1453, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25984
Transmission line model for coupled rectangular double split‐ring resonators
Authors: Yan Lei , Tang Meng , Krozer Viktor , Zhurbenko Vitaliy , Jensen Thomas , Jiang Chenhui , Johansen Tom Keinicke
Published: March 2011

In this work, a model based on a coupled transmission line formulation is developed for microstrip rectangular double split‐ring resonators (DSRRs). This model allows using the physical dimensions of the DSRRs as an input avoiding commonly used extraction of equivalent parameters. The model includes the compensation for the different circumference of two rings and allows the prediction of higher order resonance modes of the DSRR. The advantage of the developed model in comparison to the previously developed analytical representation is that it includes the coupling effect between neighboring DSRRs, which allows for an accurate modeling of densely packed multiresonator structures. The model is verified by comparison with measured DSRRs‐loaded microstrip line performance. The developed model can be effectively used to save computation resources associated with full wave electromagnetic simulations of the DSRR structures. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1311–1315, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25988
A 53–67 GHz low power and wide locking range injection‐locked frequency divider with forward body bias
Authors: Tsai Jeng‐Han , Wong Yu‐Hang
Published: March 2011

A 53–67 GHz wide locking range injection‐locked frequency divider (ILFD) has been designed and fabricated using 0.13‐μm CMOS process.By using forward body bias technique, the proposed ILFD demonstrates good performance of the wide locking range while maintaining low DC power consumption. Via a 0 dBm incident signal power, an input locking rage greater than 14 GHz (>23%) is achieved with 4 mW from supply voltage of 0.8 V. If the supply voltage further reduces to 0.6 V, the input locking rage is 6 GHz (10%) while consuming only 1.2 mW. Compared to previous reported works in high‐speed CMOS FD, the presented ILFD achieves superior figure of merit (FOM). Without extra voltage control mechanisms to increase the locking range, this FD covers whole 57–64 GHz band is suitable for integration into a 60 GHz WPAN phase‐locked loop system. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1386–1389, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25989
An electrically small Yagi antenna with enhanced bandwidth characteristics using folded cylindrical helix dipoles
Authors: Yoon Ick‐Jae , Ling Hao
Published: March 2011

An electrically small, two‐element Yagi antenna is presented.Low‐Q, folded cylindrical helix dipoles are used for the driver and the reflector element for enhanced bandwidth performance. The design is optimized, built and measured. The kr of the antenna is 0.95. The measured realized gain in the end‐fire direction is found to be 6.19 dB with a 1‐dB‐drop‐in‐realized‐gain bandwidth of 2.82%. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1231–1233, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25997
Folded monopole LC‐loaded antenna and its polarization reconfigurability
Authors: Kim S. H. , Jang J. H.
Published: March 2011

Folded monopole antenna loaded with the distributed inductors and capacitors is designed and characterized.The inductors and capacitor are realized by utilizing meanderline strips and the interdigitated structure, respectively. The resonance characteristics of the antenna are essentially determined by the uniquely arranged distributed elements, not by the length of the radiator, such that an electrically small structure can be realized. The designed antennas having a radiator length of 0.078 λ0 have good reflection characteristics and reasonable radiation gains of 0.29 dBi peak. The effect of the ground size on the resonant characteristics of the antennas is also investigated. Although the radiation characteristics are dependent upon the ground size, the variation of the resonance frequency was minimal. By utilizing the radiation characteristics depending upon the ground size of the folded monopole antenna with LC‐loadings, a polarization reconfigurable antenna can also be realized. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1197–1201, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25999
A dual‐resonant patch antenna for miniaturized active RFID tags
Authors: Wu Wei‐Jun , Yin Ying‐Zeng , Huang Yong , Wang Jie , Zhang Zhi‐Ya
Published: March 2011

A dual‐resonant patch antenna applicable to active radio frequency identification (RFID) tags is designed. The designed antenna has been skillfully integrated with the active RFID tag circuit. The antenna consists of two parts. One part comprises stacked shorted patches and a ground plane. The other part is an active tag circuit mounted on the bottom of the antenna. The measurement results reveal that the antenna has the return loss less than –10 dB within the bandwidth of 42 MHz (from 911 to 953 MHz), which totally covers the 5 MHz bandwidth from 920 to 925 MHz (The band is also allowed for passive RFID) requirement for active RFID in China. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1280–1284, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26000