bluuebunny/crossref_metadata_2025 huggingface dataset:
Xylem hydraulic conductivity and embolism in riparian plants and their responses to drought stress in desert of Northwest China
Authors: Zhou Honghua , Chen Yaning , Li Weihong , Ayup Mubarek
Published: June 2013

Riparian plants in the lower reaches of the Tarim River (Tikanlik) and Heihe River (Ulan Tug) were selected as study objects, where they suffered from different drought stresses. The differences of root and twig xylem hydraulic conductivity and embolism of the typical riparian plants, including Populus euphratica, Tamarix spp., Alhagi sparsifolia and Karelinia caspica, and their responses to drought stress were analysed. The results showed that (1) the riparian plants in the lower Tarim River suffered from more severe drought stress than those in the lower Heihe River because of their lower xylem hydraulic conductivity, and the fundamental reason resulted in different degrees of drought stresses in the two regions was groundwater depth; (2) the drought resistance of Tamarix spp. was the strongest, which could exist in a broad habitat with different degrees of water stresses, whereas A.sparsifolia and K. caspica only exist in a narrow habitat with groundwater depth less than 4 m because of their weak drought resistance; and (3) the main resistance part of water transportation of riparian plants was twig xylem when they encountered the mild drought stress, whereas it was root xylem when the riparian plants encountered severe drought stress, and riparian plants adapted the mild drought stress through limiting twig xylem hydraulic conductivity to coordinate the plant growth, while they adapted the severe drought stress through enhancing xylem hydraulic conductivity of dominant branches with strong competitiveness of sap flow and sacrificing non‐dominant branches to improve the plant survival chance. Copyright © 2013 John Wiley & Sons, Ltd.
A Solid‐Solution Approach to Mixed‐Metal Metal–Organic Frameworks – Detailed Characterization of Local Structures, Defects and Breathing Behaviour of Al/V Frameworks
Authors: Kozachuk Olesia , Meilikhov Mikhail , Yusenko Kirill , Schneemann Andreas , Jee Bettina , Kuttatheyil Anusree V. , Bertmer Marko , Sternemann Christian , Pöppl Andreas , Fischer Roland A.
Published: June 2013

The doping of [Al(OH)L]n [L = 1,4‐benzenedicarboxylate (bdc) or 1,4‐naphthalenedicarboxylate (ndc)] with vanadium ions yields crystalline porous mixed‐metal solid‐solution metal–organic frameworks (MOFs) of general formula [(AlOH)1–x(VO)xL]n (x can be varied in the whole range from 0 to 1). Several characterization methods, including powder X‐ray diffraction (PXRD), electron paramagnetic resonance (EPR), solid‐state NMR and FTIR spectroscopy, strongly support the effective incorporation of vanadium cations. The Al/V‐doped MOFs are isostructural to the parent monometallic MOFs and show a characteristic uniform dependence of the cell parameters on the metal ratios. Detailed spectroscopic investigation provided evidence that the introduced species are fairly well ordered. Interestingly, for low amounts of doped vanadium for both activated and as‐synthesized Al/V phases, the EPR results revealed the presence of vanadyl units as local defects in pseudo‐octahedral or square‐pyramidal environments, which are different from those in the parent MIL‐47(V). This observation matches the nonlinear response of the adsorption properties on variation of the composition. Remarkably, the presence of such mixed Al/V chains strongly affects the breathing behaviour of the materials. Both CO2 sorption and in situ PXRD studies validated a gradual change from highly flexible (with easily induced phase transitions) to totally rigid structures upon increasing vanadium content.
Aberrant DNA methylation of miR‐219 promoter in long‐term night shiftworkers
Authors: Shi Fengqin , Chen Xinyi , Fu Alan , Hansen Johnni , Stevens Richard , Tjonneland Anne , Vogel Ulla B. , Zheng Tongzhang , Zhu Yong
Published: June 2013

The idea that shiftwork may be carcinogenic in humans has gained widespread attention since the pioneering work linking shiftwork to breast cancer over two decades ago. However, the biomolecular consequences of long‐term shiftwork exposure have not been fully explored. In this study, we performed a genome‐wide CpG island methylation assay of microRNA (miRNA) promoters in long‐term night shiftworkers and day workers. This analysis indicated that 50 CpG loci corresponding to 31 miRNAs were differentially methylated in night shiftworkers compared to day workers, including the circadian‐relevant miR‐219, the expression of which has been implicated in several cancers. A genome‐wide expression microarray assay was carried out in a miR‐219‐overexpressed MCF‐7 breast cancer cell line, which identified 319 differentially expressed transcripts. The identified transcriptional targets were analyzed for network and functional interrelatedness using the Ingenuity Pathway Analysis (IPA) software. Overexpression of miR‐219 in MCF‐7 breast cancer cells resulted in accentuated expression of apoptosis‐ and proliferation‐related anti‐viral immunodulators of the Jak‐STAT and NF‐κβ pathways. These findings suggest that long‐term night shiftwork exposure may lead to the methylation‐dependent downregulation of miR‐219, which may in turn lead to the downregulation of immunomediated antitumor activity and increased breast cancer risk. Environ. Mol. Mutagen. 54:406–413, 2013. © 2013 Wiley Periodicals, Inc.
Hyaluronic acid‐dependent protection against UVB‐damaged human corneal cells
Authors: Li Ji‐Min , Chou Hsiu‐Chuan , Wang Ssu‐Han , Wu Chieh‐Lin , Chen Yi‐Wen , Lin Szu‐Ting , Chen Yu‐Hua , Chan Hong‐Lin
Published: June 2013

Within ultraviolet radiation, ultraviolet B (UVB) is the most energetic and damaging to humans. At the protein level, UVB irradiation downregulates the expression of antioxidant enzymes leading to the accumulation of reactive oxygen species (ROS). Due to lacking of a global analysis of UVB‐modulated corneal proteome, we investigate in vitro the mechanism of UVB‐induced corneal damage to determine whether hyaluronic acid (HA) is able to reduce UVB irradiation‐induced injury in human corneal epithelial cells. Accordingly, human corneal epithelial cell lines (HCE‐2) were irradiated with UVB, followed by incubation with low molecular weight HA (LMW‐HA, 100 kDa) or high molecular weight HA (HMW‐HA, 1,000 kDa) to investigate the physiologic protection of HMW‐HA in UVB‐induced corneal injury, and to perform a global proteomic analysis. The data demonstrated that HA treatment protects corneal epithelial cells in the UVB‐induced wound model, and that the molecular weight of HA is a crucial factor. Only HMW‐HA significantly reduces the UVB‐induced cytotoxic effects in corneal cells and increases cell migration and wound‐healing ability. In addition, proteomic analysis showed that HMW‐HA might modulate cytoskeleton regulation, signal transduction, biosynthesis, redox regulation, and protein folding to stimulate wound healing and to prevent these UVB‐damaged cells from cell death. Further studies evidenced membrane‐associated progesterone receptor component 1 (mPR) and malate dehydrogenase (MDH2) play essential roles in protecting corneal cells from UVB irradiation. This study reports on UVB‐modulated cellular proteins that might play an important role in UVB‐induced corneal cell injury and show HMW‐HA to be a potential substance for protecting corneal cells from UVB‐induced injury. Environ. Mol. Mutagen. 54:429–449, 2013. © 2013 Wiley Periodicals, Inc.
Thermal and chemical analysis of flammability and combustibility of fir wood in cone calorimeter coupled to FTIR apparatus
Authors: Batiot Benjamin , Luche Jocelyn , Rogaume Thomas
Published: June 2013

This paper deals with the thermal degradation of fir wood in a cone calorimeter under well‐ventilated atmosphere used with a piloted ignition. The thermal and chemical sample decompositions were studied with heat fluxes varying from 15 to 60 kW m−2. With the cone calorimeter results and equations found in literature, the significant parameters of fir wood sample flammability and combustibility were deduced from ignition time (tig), mass loss and gas analysis. These parameters are thermal response parameter, critical heat flux, ignition surface temperature, thermal thickness, mass loss rate, thermal inertia, effective heat of combustion, heat release rate, heat of gasification and others. Moreover, during each experiment, the main gaseous species emissions were continuously and simultaneously monitored. Furthermore, the solid degradation and combustion process for fir wood were described in details. Experimental results from cone calorimeter were compared with data found in literature, and generally, a quite good accordance was found between the both sets of results. Copyright © 2013 John Wiley & Sons, Ltd.
Experimental study on the time‐dependent smoke densities at 39 locations in a multi‐floor building through a digital smoke detector system
Authors: Xie Qiyuan , Li Qing , Plocher Thomas , Papier Isaac
Published: June 2013

The objective of this study was to quantitatively investigate some characteristics of the smoke transportation in multi‐floor buildings. Eight experiments were conducted for worst scenario. The effects of an open window in the burning room on the smoke transportation are also analyzed. The time‐dependent smoke densities at 39 locations in a half‐scale building with an atrium were measured through a digital smoke detector system. The results indicate that the chimney effect plays an important role in the smoke transportation in multi‐floor buildings with atriums. For the effects of the open window, the results suggest that the smoke densities at most locations in the building increase earlier when a window is open but have a smaller peak value than those results in the cases without any outer vents. It is suggested that a building without vertical atrium would be safer than those with long ones. More attention should be paid to those spaces when the fire protection systems are designed for buildings with atriums. The data of the time‐dependent smoke densities at tens of locations in the building are useful for the validation of smoke transportation models. Copyright © 2013 John Wiley & Sons, Ltd.
THE ROLE OF CONDITIONAL HETEROSKEDASTICITY IN IDENTIFYING AND ESTIMATING LINEAR TRIANGULAR SYSTEMS, WITH APPLICATIONS TO ASSET PRICING MODELS THAT INCLUDE A MISMEASURED FACTOR
Authors: Prono Todd
Published: June 2013

A new estimator is proposed for linear triangular systems, where identification results from the model errors following a bivariate and diagonal GARCH(1,1) process with potentially time‐varying error covariances. This estimator applies when traditional instruments are unavailable. I demonstrate its usefulness on asset pricing models like the capital asset pricing model and Fama–French three‐factor model. In the context of a standard two‐pass cross‐sectional regression approach, this estimator improves the pricing performance of both models. Set identification bounds and an associated estimator are also provided for cases where the conditions supporting point identification fail. Copyright © 2013 John Wiley & Sons, Ltd.
Limited Sampling Strategy of Mycophenolic Acid in Adult Kidney Transplant Recipients: Influence of the Post‐Transplant Period and the Pharmacokinetic Profile
Authors: Chaabane Amel , Aouam Karim , Ben Fredj Nadia , Hammouda Mouna , Chadly Zohra , El May Mezri , Boughattas Naceur , Skhiri Habib
Published: June 2013

We aimed to develop an accurate and convenient LSS for predicting MPA‐AUC0–12hours in Tunisian adult kidney transplant recipients whose immunosuppressive regimen consisted of MMF and tacrolimus combination with regards to the post‐transplant period and the pharmacokinetic profile. Each pharmacokinetic profile consisted of eight blood samples collected during the 12‐hour dosing interval. The AUC0–12hours was calculated according to the linear trapezoidal rule. The MPA concentrations at each sampling time were correlated by a linear regression analysis with the measured AUC0–12. We analyzed all the developed models for their ability to estimate the MPA‐AUC0–12hours. The best multilinear regression model for predicting the full MPA‐AUC0–12hours was found to be the combination of C1, C4, and C6. All the best correlated models and the most convenient ones were verified to be also applicable before 5 months after transplantation and thereafter. These models were also verified to be applicable for patients having or not the second peak in their pharmacokinetic profiles. For practical reasons we recommend a LSS using C0, C1, and C4 that provides a reasonable MPA‐AUC0–12hours estimation.
VOC emissions from the composting of the organic fraction of municipal solid waste using standard and advanced aeration strategies
Authors: Maulini‐Duran Caterina , Puyuelo Belen , Artola Adriana , Font Xavier , Sánchez Antoni , Gea Teresa
Published: June 2013

BACKGROUND

The emission of volatile organic compounds (VOC) during the composting process is mainly responsible for the odors generated in these types of waste treatment plants. In this work, VOC emissions from the source‐separated organic fraction of municipal solid waste (OFMSW) composting process have been investigated in 50 L pilot reactors operating under different aeration control strategies during the active decomposition stage.

RESULTS

The VOC emissions from traditional aeration control options such as oxygen feedback control or cyclic on‐off aeration have been compared with VOC emissions under an oxygen uptake rate (OUR) control strategy. Total VOC emission (mg C m‐3) and VOC composition (%) have been determined during the first active decomposition stage of composting. Study of VOC composition indicated a high presence of terpenes. Carcinogenic compounds, such as furans, have occasionally been found at very low concentration. Results indicate some differences in VOC composition according to the aeration strategy used.

CONCLUSION

The evolution of total VOC emissions was relatively similar, being high in the first days of the process. However, the results obtained show some differences in VOC composition depending on the aeration strategy used. The OUR controller provided a more steady emissions profile, which will help the performance of further gas treatment operations, specially biological systems. © 2013 Society of Chemical Industry
Appraisal of the tire derived rubber (TDR) medium for wastewater treatment under aerobic and anaerobic conditions
Authors: Naz Iffat , Khatoon Nazia , Ali Muhammad Ishtiaq , Saroj Devendra P. , Batool Syeda Ain‐ul , Ali Naeem , Ahmed Safia
Published: June 2013

BACKGROUND

The present study evaluated the effectiveness and durability of tire derived rubber (TDR) for biofilm development and related long term use in fixed biofilm reactors for wastewater treatment.

RESULTS

TDR incubated (30 ± 2°C) with activated sludge showed comparatively higher biofilm development (0.51 g) under aerobic than under anaerobic (0. 42 g) conditions after 7 weeks. During biofilm succession, a significant shift in bacterial community was observed from pathogenic to autotrophic after 4 weeks. The decreasing bacterial count (MPN index) (≈80%) (Escheria coli and feacal coliforms) and chemical oxygen demand (COD), and biological oxygen demand (BOD) (70% approx.) depicted diminishing organic load in sludge. Changes in pH and nutrients like NO2‐, NO3‐, PO43‐ and SO32‐ indicated presence of other key bacterial species with efficient nutrient consuming abilities in biofilm. Scanning electron microscopy showed few aberration and rich bacterial growth on treated TDR. Furthermore, detailed analysis through Fourier transform infrared (FTIR) spectroscopy confirmed minor transformation in TDR under anaerobic conditions.

CONCLUSION

TDR proved to be a durable and cost effective support material that can be used in aerobic fixed biofilm reactors for wastewater treatment. However, operational conditions of the reactor should be optimized to keep the biofilm structure intact and to achieve the desired wastewater treatment efficiency. © 2013 Society of Chemical Industry
Coseismic slip distribution for the Mw 9 2011 Tohoku‐Oki earthquake derived from 3‐D FE modeling
Authors: Kyriakopoulos C. , Masterlark T. , Stramondo S. , Chini M. , Bignami C.
Published: June 2013

The coseismic slip distribution of the Mw 9.0 2011 Tohoku‐Oki earthquake has been estimated by inverting near‐field onshore and offshore geodetic data, using Green's function calculated with a 3‐D finite element (FE) model. The FE model simulates several geophysical features of the subduction zone that hosted the rupture surface of the event. These features include a 3‐D geometric configuration and distribution of material properties of the tectonic system, a precise geometric configuration of the irregular rupture surface, and an irregular free surface according to the topography and bathymetry. A model that simulates rupture along the interface between the relatively weak overriding Okhotsk plate and stiff subducting slab of the Pacific Plate requires less slip to produce the observed surface deformation, compared to a model having uniform material properties across the rupture interface. Furthermore, the estimated slip of the heterogeneous model is more widely distributed over the shallow portion of the plate boundary, whereas the estimated slip of the homogeneous model is more focused updip of the epicenter. This demonstrates the sensitivity of inverse analyses of geodetic data for the 2011 Tohoku‐Oki earthquake to the simulated domain geometry and configuration of material properties.
Three‐dimensional density modeling of the EGM2008 gravity field over the Mount Paekdu volcanic area
Authors: Choi Sungchan , Oh Chang‐Whan , Götze H.‐J.
Published: June 2013

Here we use the global gravity field data set EGM2008 for 3‐D crustal density modeling of the Mount Paekdu stratovolcano and surrounding area located on the border between North Korea and China. Curvature analysis and Euler deconvolution are used to assist interpretation, and the 3‐D model is constrained by multiple geological and geophysical data sets. Mount Paekdu is characterized by a low Bouguer anomaly of −110 × 10−5 m/s2, which is caused by the combined gravity effects of (1) a depth to the Moho of about 40 km, (2) a zone with lower P wave velocity and density than the surrounding, (3) low density volcanic rocks on the surface, and (4) the presence of a magma chamber that has not previously been identified. The modeled magma chamber has a mean thickness of 5 km and a density of about 2350 kg/m3 and is located <10 km from the surface. Magma chambers are also modeled beneath Mount Wangtian and Mount Nampotae. However, the results of the 3‐D density modeling do not confirm the existence of a previously proposed midcrustal low‐velocity zone in the area 70 km to the north of Mount Paekdu. Since the Pliocene, volcanic activity in the Mount Paekdu region has migrated from the east coast of North Korea to the northwest, following the path of NW‐SE trending faults.
The link between springtime total ozone and summer UV radiation in Northern Hemisphere extratropics
Authors: Karpechko A. Yu. , Backman L. , Thölix L. , Ialongo I. , Andersson M. , Fioletov V. , Heikkilä A. , Johnsen B. , Koskela T. , Kyrölä E. , Lakkala K. , Myhre C. L. , Rex M. , Sofieva V. F. , Tamminen J. , Wohltmann I.
Published: June 2013

The link between stratospheric ozone decline and ultraviolet (UV) radiation increase at the Earth's surface is well established. In the Northern Hemisphere extratropics, stratospheric ozone is accumulated from autumn to spring as a result of transport from its source region in the tropics. The amount of accumulated ozone varies from year to year due to natural dynamical variability and chemical destruction by natural and anthropogenic substances. Observational and modeling studies show that these total ozone anomalies persist in the extratropics from spring to summer. Here we analyze time series of ground‐based UV measurements and satellite retrievals of total ozone and UV radiation and demonstrate that there is a strong link between springtime total ozone and summer UV anomalies in the Northern Hemisphere extratropics. In some regions, the interannual variability in springtime ozone abundance explains 20–40% of the summer UV variability, and this relation can be used for improving seasonal UV forecasts. Using chemistry transport models, we estimate the influence of polar chemical ozone loss on the summer UV north of 35°N. We estimate that the massive Arctic ozone depletion 2011 increased the March–August cumulative erythemal clear‐sky UV dose in the Northern Hemisphere extratropics by 3–4% compared to the climatology, with about 75% of the increase accumulated after the breakup of the polar vortex. This result strongly suggests that the effect of seasonal ozone anomaly persistence should be included in the assessment of the impacts of polar ozone losses.
Dominant roles of subgrid‐scale cloud structures in model diversity of cloud radiative effects
Authors: Zhang Feng , Liang Xin‐Zhong , Li Jiangnan , Zeng Qingcun
Published: June 2013

Today, large model discrepancies exist in estimated cloud radiative effects (CREs) and irradiances across 1‐D radiative transfer schemes aimed for climate models. The primary purpose of this study is to understand physical causes of such model discrepancies, especially in CREs under partly cloudy sky. To achieve this goal, the unique Cloud‐Aerosol‐Radiation (CAR) ensemble modeling system was employed, offline driven by the ERA‐Interim global data for July 2004 with no feedback considered. For evaluating each individual contribution from the existing scheme diversity of cloud horizontal inhomogeneity, cloud optical properties, cloud vertical overlap, and gas absorptions, several sets of numerical experiments were conducted. It is the first time to explicitly demonstrate that after removing most of the disagreement in cloud fields, model spreads of CREs among the CAR's seven major radiation schemes, as well as those of radiative fluxes, dramatically diminish. Taking global mean CREs for example, their current model ranges can decrease to <4 W m−2 from about 10 W m−2 for shortwave and also to <4 W m−2 from 5–8 W m−2 for longwave. Dominant roles of subgrid‐scale cloud structures (including vertical overlap and horizontal variability) were proven in general, explaining about 40–75% of the total model spreads. We have also found that model spreads of CREs are very sensitive to cloud cover fractions. Such nonlinear sensitivity can be largely reduced after removing the model difference in the treatments of cloud vertical overlap.
Gas‐phase interactions of organotin compounds with glycine
Authors: Latrous Latifa , Tortajada Jeanine , Haldys Violette , Léon Emmanuelle , Correia Catarina , Salpin Jean‐Yves
Published: June 2013

Gas‐phase interactions of organotins with glycine have been studied by combining mass spectrometry experiments and quantum calculations. Positive‐ion electrospray spectra show that the interaction of di‐ and tri‐organotins with glycine results in the formation of [(R)2Sn(Gly)‐H]+and [(R)3Sn(Gly)]+ions, respectively. Di‐organotin complexes appear much more reactive than those involving tri‐organotins. (MS/MS) spectra of the [(R)3Sn(Gly)]+ions are indeed simple and only show elimination of intact glycine, generating the [(R)3Sn]+carbocation. On the other hand, MS/MS spectra of [(R)2Sn(Gly)‐H]+complexes are characterized by numerous fragmentation processes. Six of them, associated with elimination of H2O, CO, H2O + CO and formation of [(R)2SnOH]+(−57 u),[(R)2SnNH2]+( −58 u) and [(R)2SnH]+(−73 u), are systematically observed. Use of labeled glycines notably concludes that the hydrogen atoms eliminated in water and H2O + CO are labile hydrogens. A similar conclusion can be made for hydrogens of [(R2)SnOH]+and [(R2)SnNH2]+ions. Interestingly, formation [(R)2SnH]+ions is characterized by a migration of one the α hydrogen of glycine onto the metallic center. Finally, several dissociation routes are observed and are characteristic of a given organic substituent.

Calculations indicated that the interaction between organotins and glycine is mostly electrostatic. For [(R)2Sn(Gly)‐H]+complexes, a preferable bidentate interaction of the type η2‐O,NH2 is observed, similar to that encountered for other metal ions. [(R)3Sn]+ions strongly stabilize the zwitterionic form of glycine, which is practically degenerate with respect to neutral glycine. In addition, the interconversion between both forms is almost barrierless. Suitable mechanisms are proposed in order to account for the most relevant fragmentation processes. Copyright © 2013 John Wiley & Sons, Ltd.
Understanding chemical reactivity for homo‐ and heterobifunctional protein cross‐linking agents
Authors: Chen Fan , Nielsen Simone , Zenobi Renato
Published: June 2013

Chemical cross‐linking, combined with mass spectrometry, has been applied to map three‐dimensional protein structures and protein–protein interactions. Proper choice of the cross‐linking agent, including its reactive groups and spacer arm length, is of great importance. However, studies to understand the details of reactivity of the chemical cross‐linkers with proteins are quite sparse. In this study, we investigated chemical cross‐linking from the aspects of the protein structures and the cross‐linking reagents involved, by using two structurally well‐known proteins, glyceraldehyde 3‐phosohate dehydrogenase and ribonuclease S. Chemical cross‐linking reactivity was compared using a series of homo‐ and hetero‐bifunctional cross‐linkers, including bis(sulfosuccinimidyl) suberate, dissuccinimidyl suberate, bis(succinimidyl) penta (ethylene glycol), bis(succinimidyl) nona (ethylene glycol), m‐maleimidobenzoyl‐N‐hydroxysulfosuccinimide ester, 2‐pyridyldithiol‐tetraoxaoctatriacontane‐N‐hydrosuccinimide and succinimidyl‐[(N‐maleimidopropionamido)‐tetracosaethyleneglycol]ester. The protein structure itself, especially the distances between target amino acid residues, was found to be a determining factor for the cross‐linking efficiency. Moreover, the reactive groups of the chemical cross‐linker also play an important role; a higher cross‐linking reaction efficiency was found for maleimides compared to 2‐pyrimidyldithiols. The reaction between maleimides and sulfhydryl groups is more favorable than that between N‐hydroxysuccinimide esters and amine groups, although cysteine residues are less abundant in proteins compared to lysine residues. Copyright © 2013 John Wiley & Sons, Ltd.
Structural determination of nerve agent markers using gas chromatography mass spectrometry after derivatization with 3‐pyridyldiazomethane
Authors: Nyholm Jenny Rattfelt , Gustafsson Tomas , Östin Anders
Published: June 2013

Nerve agents are a class of organophosphorous chemicals that are prohibited under the Chemical Weapons Convention. Their degradation products, phosphonic acids, are analyzed as markers of nerve agent contamination and use. Because the phosphonic acids are non‐volatile and very polar, their identification by GC‐MS requires a derivatization step prior to analysis. Standard derivatization methods for gas‐chromatography electron‐impact mass‐spectrometry analysis give very similar spectra for many alkyl phosphonic acid isomers, which complicates the identification process. We present a new reagent, 3‐pyridyldiazomethane, for preparing picolinyl ester derivatives of alkyl methylphosphonic acids facilitating the determination of their structure by enhancing predictable fragmentation of the O‐alkyl chain. This fragmentation is directed by the nitrogen nucleus of the pyridyl moiety that abstracts hydrogen from the O‐alkyl chain, inducing radical cleavage of the carbon–carbon bonds and thereby causing extensive fragmentation that can be used for detailed structure elucidation of the O‐alkyl moiety. The separability of related isomers was tested by comparing the spectra of the picolinyl esters formed from twelve hexyl methylphosphonic acid isomers. Spectral library matches and principal component analysis showed that the picolinyl esters were more effectively separated than the corresponding trimethylsilyl derivatives used in the standard operating procedures. The suggested method will improve the unambiguous structural determination process for phosphonic acids. Copyright © 2013 John Wiley & Sons, Ltd.
Development of sheath‐flow probe electrospray ionization (SF‐PESI)
Authors: Rahman Md. Obaidur , Mandal Mridul Kanti , Shida Yasuo , Ninomiya Satoshi , Chen Lee Chuin , Nonami Hiroshi , Hiraoka Kenzo
Published: June 2013

Probe electrospray ionization (PESI) uses a sharp solid needle as electrospray emitter. This method was found to be applicable to the analysis of real‐world samples with high concentrations of salts and detergents without sample pretreatment. Since PESI is only applicable to wet samples but not to dry samples, sheath‐flow PESI (SF‐PESI) has been developed. The metal needle was inserted into the fine plastic capillary with a protrusion of 0.1–0.2 mm from the capillary terminus. The solvent was supplied continuously through the capillary. At the lowest position of the probe, solvent flowing out from the capillary makes the sample wet and extracts the analytes from the surface. The extracted analytes were electrosprayed at the highest position of the needle. SF‐PESI was successfully applied to samples such as narcotics, tablets, bill, fruits, potatoes, etc. Copyright © 2013 John Wiley & Sons, Ltd.
Improved repair of chondral and osteochondral defects in the ovine trochlea compared with the medial condyle
Authors: Orth Patrick , Meyer Heinz‐Lothar , Goebel Lars , Eldracher Mona , Ong Mei Fang , Cucchiarini Magali , Madry Henning
Published: June 2013

Associations between topographic location and articular cartilage repair in preclinical animal models are unknown. Based on clinical investigations, we hypothesized that lesions in the ovine femoral condyle repair better than in the trochlea. Full‐thickness chondral and osteochondral defects were simultaneously established in the weightbearing area of the medial femoral condyle and the lateral trochlear facet in sheep, with chondral defects subjected to subchondral drilling. After 6 months in vivo, cartilage repair and osteoarthritis development was evaluated by macroscopic, histological, immunohistochemical, and biochemical analyses. Macroscopic and histological articular cartilage repair and type‐II collagen immunoreactivity were better in the femoral trochlea, regardless of the defect type. Location‐independently, osteochondral defects induced more osteoarthritic degeneration of the adjacent cartilage than drilled chondral lesions. DNA and proteoglycan contents of chondral defects were higher in the condyle, reflecting physiological topographical differences. The results indicate that topographic location dictates the structural patterns and biochemical composition of the repair tissue in sheep. These findings suggest that repair of cartilage defects at different anatomical sites of the ovine stifle joint needs to be assessed independently and that the sheep trochlea exhibits cartilage repair patterns reflective of the human medial femoral condyle. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1772–1779, 2013
Pivot Algorithm and Push‐off Method for Efficient System Generation of All‐Atom Polymer Melts: Application to Hydroxyl‐Terminated Polybutadiene
Authors: Fröhlich Markus G. , Sewell Thomas D.
Published: June 2013

Procedures used to generate initial conditions for all‐atom molecular dynamics (MD) simulations of amorphous polymer systems are described. The pivot algorithm is applied directly to produce unbranched hydroxyl‐terminated cis‐1,4‐polybutadiene molecules with chain lengths ranging from 8 to 64 monomeric units (32 to 256 carbon atoms), based on the OPLS all‐atom force field. The generated molecular configurations are characteristic of (pseudo‐) ideal conditions and therefore exhibit the same properties as polymer chains in a melt. We analyze both the mean squared chain dimensions and their distributions in order to validate the correctness of this approach. The chains are efficiently packed into 3d‐periodic simulation cells using the push‐off method and subsequently equilibrated by standard MD. Together, the pivot algorithm and push‐off method provide the means for efficient generation of equilibrated dense polymer melts for multi‐million‐atom systems.
An IE‐ODDM Scheme Combined With Efficient Direct Solver for 3D Scattering Problems
Authors: Chen Jialin , Wang Min , Li Shangsheng , Zhu Mingbo , Yu Jing , Li Xiangping
Published: June 2013

An improved scheme of integral equation‐based overlapped domain decomposition method combined with an efficient direct solver based on hierarchical LU (H‐LU) decomposition is proposed for the three‐dimensional (3D) scattering problems. In this scheme, the H‐LU direct method is utilized to solve the self‐impedance matrix equation in each extended subdomain; simultaneously, the multilevel fast multipole algorithm is applied to complete the matrix vector product operation of mutual‐impedance matrix between different subdomains. In the H‐LU operation, a recompressed adaptive cross approximation technique is used to generate the low‐rank approximations of the far‐field matrices. After integrating all the techniques, the proposed scheme is very efficient especially for 3D electromagnetic scattering problems with multiple incident fields such as the computation of the monostatic radar cross section. Some examples are provided to demonstrate its accuracy and efficiency. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2027–2033, 2013
Comparison of Different MIMO Antenna Arrays and User's Effect on Their Performances
Authors: Gómez‐Calero Carlos , Jamaly Nima , Martínez Ramón , de Haro Leandro
Published: June 2013

Multiple‐input multiple‐output (MIMO) systems have entailed a great enhancement in wireless communications performances. The use of multiple antennas at each side of the radio link has been included in recent drafts and standards such as WLAN, WIMAX, or DVB‐T2. The MIMO performances depend on the antenna array characteristics and thus several aspects have to be taken into account to design MIMO antennas. In the literature, many articles can be found in terms of capacity or antenna design, but in this article, different types of antenna arrays for MIMO systems are measured in a reverberation chamber with and without a phantom as a user′s head. As a result, the MIMO performances are degraded by the user in terms of efficiency, diversity gain, and capacity. Omnidirectional antennas such as monopoles with high radiation efficiency offer the highest performance for a rich scattering nonline of sight indoor environment. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2039–2043, 2013
A High‐Voltage Driving 60‐GHz Power Amplifier with Psat of 13 dBm and PAE of 9.1% in 90‐nm CMOS for IEEE 802.11ad Communication Systems
Authors: Chang Jin‐Fa , Lin Yo‐Sheng
Published: June 2013

A high‐voltage (3 V) driving 60‐GHz power amplifier (PA) for direct‐conversion transceiver using standard 90 nm CMOS technology is reported. The PA comprises two cascode stages with inductive load and low‐impedance interstage matching, followed by a common‐source output stage. To increase the saturated output power (Psat) and power‐added efficiency (PAE), the output stage adopts a two‐way power dividing and combining architecture. Instead of the area‐consumed Wilkinson power divider and combiner, miniature low‐loss LC power divider and combiner (IL = 0.536 dB @60 GHz) are used. This in turn results in further Psat and PAE enhancement. The PA consumes 176.2 mW and achieves power gain (S21) of 17.9 ± 3.7 dB, input‐port input reflection coefficient (S11) of −5.8 to −7.3 dB, output‐port input reflection coefficient (S22) of −10.4 to −26.3 dB, and reverse isolation (S12) of −56.4 to −81.7 dB for frequencies 50–60 GHz. In addition, for frequencies 50–60 GHz, the PA achieves output 1‐dB compression point (OP1dB) of 6.6–7.8 dBm, Psat of 10.6–13 dBm and maximum PAE of 9.1%, one of the best PAE results ever reported for a 60 GHz CMOS PA. These results demonstrate the proposed PA architecture is very promising for 60‐GHz short‐range communication system applications. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2033–2039, 2013
Triband Microstrip–Based Radiating Structure Design using Split Ring Resonator and Complementary Split Ring Resonator
Authors: Patel Shobhit K. , Kosta Yogeshwar
Published: June 2013

In this letter, a novel microstrip patch antenna is designed with the use of both split ring resonator (SRR) and complementary split ring resonator (CSRR). The use of SRR and CSRR in the substrate and base material, respectively, have changed the behavior of the material and now it acts as metamaterial. Metamaterials exhibit new electromagnetic response functions that cannot be found in nature. The addition of SRR and CSRR in the regular patch changes the permeability (µ) and the permittivity (ε) of the material. Due to the change in these two properties of the material the resonance changes and now patch design shows the multiband result. Here the design shows three bands with its center frequencies 3.31, 3.88, and 4.61 GHz. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2219–2222, 2013
Artificial Neural Networks for the Chromatic Dispersion Prediction of Photonic Crystal Fibers
Authors: Rodríguez‐Esquerre V. F. , Isídio‐Lima J. J. , Dourado‐Sisnando A. , Simões Silva F. G.
Published: June 2013

Multilayer perceptron artificial neural networks have been used for the efficient evaluation and prediction of the chromatic dispersion properties of microstructured optical fibers, with very low computational resources and efforts in an easy, efficient, and simple way. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2179–2181, 2013
Wideband Folded Bowtie Antenna With Γ‐Shaped Strip Feed and Tuning Stubs
Authors: Zhang Zhi‐Ya , Zuo Shao‐Li , Zhao Jia‐Yue
Published: June 2013

The wideband performance of a bowtie antenna with Γ‐shaped strip feed and tuning stubs is presented. Besides two folded elements connecting the patches of the bowtie dipole for a compact dimension, the Γ‐shaped strip feed structure and the four tuning stubs to effectively improve the impendence matching can be used for bandwidth enhancement. A wideband impedance characteristics of about 58.6% for VSWR ≤ 1.5 ranging from 1.58–2.89 GHz is obtained and the stable peak gain of around 9 dBi, unidirectional radiation patterns and low cross‐polarization over the whole operating band are also achieved. It is very suitable for the recent wireless communication services for the indoor‐base station such as 3G, WiFi, WiMax, Bluetooth, and LTE/2.5 applications, and so on. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2145–2149, 2013
Novel Coplanar Waveguide Circulator Using Metallized Yttrium Iron Garnet Disk
Authors: Soh Wee Tee , Tan Chin Yaw , Ong Chong Kim
Published: June 2013

Through numerical simulations, we present a novel coplanar waveguide (CPW) circulator using bulk Yttrium Iron Garnet (YIG) as the active material. This simple design allows circulation to be achieved using CPW lines, by having a metallized YIG disk on top of the center conductor. The metallization serves to direct the electromagnetic fields in the center region such that the circulation conditions can be satisfied. Simulation results show good nonreciprocal behavior. At circulation frequency of 9.88 GHz, an insertion loss of −0.37 dB, return loss of −18.5 dB, and isolation of −16.8 dB is achieved. As CPW lines are used, and the YIG ferrite is placed on top of the CPW line, this circulator can be easily integrated into monolithic microwave integrated circuits (MMICs). © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2143–2145, 2013
Compact Bandstop Filter for UHF in Modified Meander Arrangement with Capacitors
Authors: Rudziński Adam , Łysiuk Anna , Godziszewski Konrad
Published: June 2013

We present a novel bandstop microstrip filter with coupling capacitors. The microstrip is arranged in a meander‐like pattern, with particular segments coupled by capacitors. This layout provides good results and reduced filter's size, with readily tunable transmittance that can be modified for notch‐like operation or wide stop band. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2110–2113, 2013
High Efficiency Two‐Stage Unbalanced Doherty Power Amplifier for Lte Applications
Authors: Jang Dong‐Hee , Kim Ji‐Yeon , Kim Jong‐Heon
Published: June 2013

A 16 W two‐stage unbalanced Doherty amplifier with high efficiency is proposed for the long‐term evolution test signal. The proposed amplifier by using the gate bias control of the drive and final peaking amplifier demonstrated a 43% power added efficiency with an adjacent channel leakage ratio of −37 dBc at 7.3 dB output power back‐off. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2176–2179, 2013
Compact Filter Design Using SIR and Tapped Asymmetrical Coupling Path
Authors: Luo Xun , Qian Huizhen
Published: June 2013

A series of compact bandpass filters with single‐ and dual‐band are proposed using the stepped impedance resonator (SIR) and tapped asymmetrical coupling path. The resonances are introduced by the SIR. Meanwhile, the tapped asymmetrical coupling path could use the controlled coupling for passband enhancement around the resonances for single‐ and dual‐band frequency responses. The equivalent circuit model of the proposed scheme is introduced. Based on the mechanism mentioned earlier, two compact bandpass filters with single‐ and dual‐band are designed with high performance. Good agreement between the simulated and measured results is achieved. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2059–2062, 2013
Ultra‐Wideband Slot Antenna With Frequency Band‐Stop Operation
Authors: Ojaroudi Mohammad , Ojaroudi Nasser
Published: June 2013

In this article, a novel ultra‐wideband (UWB) slot antenna with frequency band‐stop performance is designed and manufactured. The fabricated antenna has the frequency band of 3.01 to more than 11.07 GHz with a rejection band around 5–6 GHz. Good VSWR and radiation pattern characteristics are obtained in the frequency band of interest. Simulated and measured results are presented to validate the usefulness of the proposed antenna structure for UWB applications. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2020–2023, 2013
Miniature Planer Monopole Antenna with Dual‐Band Rejection Characteristics for UWB Applications
Authors: Naser‐Moghadasi M. , Sadeghzadeh R. A. , MohammadLou R. Khajeh , Jalali M. , Virdee B. S.
Published: June 2013

A novel and compact monopole antenna with dual‐band notch functionality is presented for ultra‐wideband applications. The band notches are realized by nesting two slots within the radiating patch, which are constituted by etching a symmetrical Г‐shaped slot in the form of a meandering line, and the second slot is a U‐shaped slot. Cross‐coupling between the slot elements is designed to be minimal. Experimental results show that the prototype antenna of dimensions 17 × 10 × 1.6 mm3 exhibits an impedance bandwidth extending from 3.1 to 12 GHz for VSWR ≤ 2, except at the two stop band located between 4.96 and 5.95 GHz (WLAN) and 7.725–8.5 GHz (ITU‐R). Moreover, the antenna has good radiation characteristics, a stable gain and good time‐domain behavior to satisfy the requirement of the current wireless communication standards. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1977–1981, 2013
Two‐Ray Modeling of Recombination Effects in The Presence of a Phase Conjugation Array
Authors: Chan Pak , Fusco Vincent
Published: June 2013

This article describes by means of a simple model how signal recombination effects behave under the influence of phase conjugating retrodirective array (RDA) technology. A two‐ray ground reflection model is used to predict the operational advantages of RDA technology in multipath rich environments. The simulation results show that advantageous signal recombination occurs due to automatic self‐phasing. As the number of elements in the RDA increases, the fading effect normally observed due to out of phase multipath signal is mitigated to the extent that the system approaches that of one operating in a free space environment. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1987–1989, 2013
Quadrature Operation Point Locked Techniques for Interrogating Extrinsic Fabry‐Perot Interferometric Sensors
Authors: Shang‐hui Xiao , Yi Jiang , Da Liu , Jun Tang
Published: June 2013

A quadrature operation point locked technique for interrogating extrinsic Fabry‐Perot interferometric (EFPI) sensors is experimentally demonstrated. The voltage of quadrature operation point is set as the reference, and the output signal from the EFPI is filtered and compared with the reference. The difference voltage is used to shift the wavelength of the laser by changing the operation temperature. Experimental results show that the interrogation system can be locked at the quadrature operation point within a temperature range of 50°C. A linear output is realized when the system is locked. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2117–2120, 2013
A Wideband Cmos Phase Shifter With A Phase Tuning Bit for Ku‐Band Mobile Satellite Communication
Authors: Cho Moon‐Kyu , Kim Jeong‐Geun , Baek Donghyun
Published: June 2013

This article presents a Ku‐band switched path type phase shifter in a standard 0.13 µm CMOS technology. The phase shifter consists of phase shifting filter networks, DPDT and SPDT switches, a tuning bit, and digital control logic. The phase coverage of the phase shifter is 354° with the LSB of 5.625°. The measured insertion loss is less than 16 dB. The input and output return losses are more than 12 dB. The RMS phase error and amplitude variation are less than 7.6° and 0.3 dB at 10.7–15 GHz, respectively. When the tuning bit is activated, the RMS phase error of 6.3° and the RMS amplitude variation of 0.4 dB are achieved at 10.7–15 GHz. The input P1dB over ∼11 dBm is achieved at 10–15 GHz. The current consumption is nearly zero with 1.2 V supply voltage. The chip size is 1.46 × 0.82 mm2 including pads. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2120–2124, 2013
Reduction of Cross Polarization of Slotted Microstrip Antenna Array Using Spiral‐Ring Resonator
Authors: Kumar Ghosh Chandan , Rana Biswarup , Parui Susanta Kumar
Published: June 2013

Design of a (2 × 2) E‐shaped microstrip patch antenna array integrated with spiral‐ring resonators (SRRs) is introduced for the reduction of cross‐polar (XP) radiation. The addition of SRRs in the array structure does not affect other characteristics of the array antenna. The array is designed to function in the 5.25 GHz that corresponds to IEEE 802.11a wireless LAN application. The characteristic analysis such as return loss (RL), bandwidth (BW), and radiation patterns of the antenna with and without SRRs have been investigated. The array offers a BW of 405 MHz (for RL < −10 dB) covering frequencies ranges from 5.175 to 5.580 GHz and gain of 12.84 dBi has been achieved. The array has been studied both numerically and experimentally by introducing SRRs. The SRR geometry has been optimized for minimum XP radiation. The XP radiation has been reduced by 7 dB with two SSRs and 12.0 dB by four SRRs of similar geometry, placed in between the patch elements of the array structure. Prototype antennas with and without SRRs have been fabricated tested and a remarkable agreement is obtained between the measured and the simulated results. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2083–2088, 2013