bluuebunny/crossref_metadata_2025 huggingface dataset:
Texture, composition and anatomy of spinach leaves in relation to nitrogen fertilization
Authors: Gutiérrez‐Rodríguez Eduardo , Lieth Heiner J , Jernstedt Judith A , Labavitch John M , Suslow Trevor V , Cantwell Marita I
Published: July 2012

BACKGROUND: The postharvest quality and shelf life of spinach are greatly influenced by cultural practices. Reduced spinach shelf life is a common quandary in the Salinas Valley, California, where current agronomic practices depend on high nitrogen (N) rates. This study aimed to describe the postharvest fracture properties of spinach leaves in relation to N fertilization, leaf age and spinach cultivar.

RESULTS: Force–displacement curves, generated by a puncture test, showed a negative correlation between N fertilization and the toughness, stiffness and strength of spinach leaves (P > 0.05). Younger leaves (leaves 12 and 16) from all N treatments were tougher than older leaves (leaves 6 and 8) (P > 0.05). Leaves from the 50 and 75 ppm total N treatments irrespective of spinach cultivar had higher fracture properties and nutritional quality than leaves from other N treatments (P > 0.05). Total alcohol‐insoluble residues (AIR) and pectins were present at higher concentrations in low‐N grown plants. These plants also had smaller cells and intercellular spaces than high‐N grown leaves (P > 0.05).

CONCLUSION: Observed changes in physicochemical and mechanical properties of spinach leaves due to excess nitrogen fertilization were significantly associated with greater postharvest leaf fragility and lower nutritional quality. Copyright © 2012 Society of Chemical Industry
Texture improvement of fresh and frozen mangoes with pectin methylesterase and calcium infusion
Authors: Sirijariyawat Arpassorn , Charoenrein Sanguansri , Barrett Diane M
Published: July 2012

BACKGROUND: A major problem of mango products is texture loss. The effect of commercial pectin methylesterase (PME) and calcium infusion on improvement of the texture of both fresh and frozen‐thawed mango cubes was investigated in the present study.

RESULTS: The weight gain and moisture content of mango samples were greater at relatively high vacuum level (10 kPa). The PME activity of samples infused with PME and calcium at 10 kPa increased fourfold in comparison with that of control and water‐infused samples. The combined effect of PME and calcium was found to improve the texture and microstructure of both fresh and frozen‐thawed mangoes. Fresh mangoes infused with PME and calcium at 10 kPa showed significantly higher firmness than control fresh samples. Frozen‐thawed mangoes infused with PME and calcium at 50 kPa and atmospheric pressure had superior texture and microstructure in comparison with control frozen‐thawed samples.

CONCLUSION: The results of the present analysis allow for a better appreciation of the role of PME, calcium and appropriate infusion conditions in improving the texture of both fresh and frozen‐thawed mangoes. Copyright © 2012 Society of Chemical Industry
Minimally invasive approaches for gastric cancer—Korean experience
Authors: Yang Han‐Kwang , Suh Yun‐Suhk , Lee Hyuk‐Joon
Published: July 2012

Laparoscopic surgery in Korea increased rapidly because of the early detection of gastric cancer by the development of diagnostic tools and nationwide screening. The Korean Laparoscopic Gastrointestinal Surgery Study Group (KLASS group) played a leading role in various projects related with minimally invasive surgery. The justification of minimally invasive procedures including robotic surgery, sentinel‐node biopsy, or single‐port surgery/Natural Orifice Transluminal Endoscopic Surgery (NOTES) must be predetermined by the clinical trial before a wide application, and the medical industry as well as surgeons should have great responsibility. J. Surg. Oncol. 2013;107:277–281. © 2012 Wiley Periodicals, Inc.
Ablative therapies in adrenal tumors: Primary and metastatic
Authors: Pua Bradley B. , Solomon Stephen B.
Published: July 2012

A large number of adrenal tumors are now identified either incidentally or associated with a metastatic workup for cancer. While the vast majority of these lesions are benign, those that prove to be primary or secondary cancers are traditionally treated with surgical resection. A wide variety of alternative, less invasive therapies exist. One of these, thermal ablation, is examined herein. J. Surg. Oncol. 2012; 106:626–631. © 2012 Wiley Periodicals, Inc.
Translation and preliminary validation of the english version of the DUX questionnaire for lower extremity bone tumor patients (Bt‐DUX): A disease‐specific measure for quality of life
Authors: Bekkering W. Peter , Billing Laura , Grimer Rob J. , Vlieland Theodora P.M. Vliet , Koopman Hendrik M. , Nelissen Rob G.H.H. , Taminiau Antonie H.M.
Published: July 2012

Purpose

To translate the Dutch DUX questionnaire for lower extremity bone tumor patients (Bt‐DUX), a disease‐specific quality of life (QoL) instrument, into the English (UK) language and preliminary validate the English version in patients who were treated for lower‐extremity bone tumors.

Methods

Adaptation and translation process included forward translation, back‐translation, and a review of the back‐translation by an expert committee. Internal consistency and validity of the translated questionnaire were examined in a sample of adolescents treated for lower extremity osteosarcoma in the United Kingdom. Assessments included the Bt‐DUX, the Toronto Extremity Salvage Score (TESS), the Short Form (SF)‐36, and the TNO‐AZL Questionnaire for Adult's Quality of Life (TAAQOL).

Results

Seventeen patients (7 ♂ and 10 ♀), median age 19.9 (range: 16–25) years completed the questionnaires. Mean Bt‐DUX score was 38.8 (range: 23–78), with Cronbach's α being 0.95 domain–total correlations ranged between 0.84 and 0.93 (P < 0.01). Spearman's correlation coefficients between the Bt‐DUX total and domain scores and corresponding TAAQOL and SF‐36 scores were overall moderate to good and reaching statistical significance in a most cases.

Conclusion

Preliminary evidence suggests that the English Bt‐DUX translation is a valid disease‐specific instrument for evaluating QoL of adolescents with lower extremity bone cancer. J. Surg. Oncol. 2013;107:353–359. © 2012 Wiley Periodicals, Inc.
A multidisciplinary approach to giant cell tumors of tendon sheath and synovium—A critical appraisal of literature and treatment proposal
Authors: van der Heijden Lizz , Gibbons C.L. Max H. , Hassan A. Bass , Kroep Judith R. , Gelderblom Hans , van Rijswijk Carla S.P. , Nout Remi A. , Bradley Kevin M. , Athanasou Nick A. , Dijkstra P.D. Sander , Hogendoorn Pancras C. W. , van de Sande Michiel A. J.
Published: July 2012

Giant cell tumors deriving from synovium are classified into a localized (GCT of tendon sheath; GCT‐TS) and diffuse form (diffuse‐type GCT, Dt‐GCT). We propose a multidisciplinary management based upon a systematic review and authors' opinion. Open excision for GCT‐TS and open synovectomy (plus excision) for Dt‐GCT is advised to reduce the relatively high recurrence risk. External beam radiotherapy should be considered in severe cases, as Dt‐GCT commonly extends extra‐articular. J. Surg. Oncol. 2013;107:433–445. © 2012 Wiley Periodicals, Inc.
Simultaneous, sequential quantitative achiral–chiral analysis by two‐dimensional liquid chromatography
Authors: Venkatramani Cadapakam J. , Wigman Larry , Mistry Kavita , Chetwyn Nicholas
Published: July 2012

In general, chromatographic analysis of chiral compounds involves a minimum of two methods; a primary achiral method for assay and impurity analysis and a secondary chiral method for assessing chiral purity. Achiral method resolves main enantiomeric pairs of component from potential impurities and degradation products and chiral method resolves enantiomeric pairs of the main component and diastereomer pairs. Reversed‐phase chromatographic methods are preferred for assay and impurity analysis (high efficiency and selectivity) whereas chiral separation is performed by reverse phase, normal phase, or polar organic mode. In this work, we have demonstrated the use of heart‐cutting (LC–LC) and comprehensive two‐dimensional liquid chromatography (LC × LC) in simultaneous, sequential achiral and chiral analysis and quantitation of minor, undesired enantiomer in the presence of major, desired enantiomer using phenylalanine as an example. The results were comparable between LC–LC and LC × LC with former offering better sensitivity and accuracy. The quantitation range was over three orders of magnitude with undesired D‐phenylalanine detected at approximately 0.3% in the presence of predominant, desired L‐phenylalanine (99.7%). The limit of quantitation was comparable to conventional high‐performance liquid chromatography. A reversed‐phase C18 achiral column in the primary and reversed‐phase Chirobiotic Tag chiral column in the secondary dimension were used with a compatible mobile phase.
Chemometric analysis of targeted 3DLC‐DAD data for accurate and precise quantification of phenytoin in wastewater samples
Authors: Bailey Hope P. , Rutan Sarah C. , Stoll Dwight R.
Published: July 2012

A variety of pharmaceuticals have been found in various water systems, including wastewater treatment effluent. Due to the possible environmental and human health implications, it is important to be able to quickly and reliably quantify the amount of pharmaceuticals and personal care products that may be present in such samples. To this end, a new chromatographic analysis technique involving three dimensions of liquid chromatography, including selective comprehensive separations in the second and third dimensions, was applied to the analysis of a wastewater treatment plant effluent (WWTPE) sample using both standard addition and external calibrations. Iterative key set factor analysis alternating least squares with the application of both sample and spectral selectivity constraints was used to resolve the phenytoin peak at a concentration corresponding to about 40 parts‐per‐trillion using UV absorbance detection. Both the precision and accuracy of the method are investigated. We determined that the concentration of phenytoin in WWTPE using selective three dimensional liquid chromatography with diode array detection was 42 ± 1 ng/L, after resolution from an unknown interferent. The estimated concentration was not significantly different from that obtained by the reference 2DLC/MS/MS method, but was four and a half times more precise.
Multidimensional liquid chromatography for the determination of chiral coumarins and furocoumarins in Citrus essential oils
Authors: Dugo Paola , Russo Marina , Sarò Mariagiovanna , Carnovale Caterina , Bonaccorsi Ivana , Mondello Luigi
Published: July 2012

In this work the enantiomeric distribution of chiral coumarins (meranzin and epoxyaurapten), and furocoumarins (oxypeucedanin, byakangelicol, and epoxybergamottin) in different Citrus essential oils (lemon, lime, grapefruit, and bitter orange) was determined by means of a heart‐cutting multidimensional‐liquid chromatography (MD‐LC) system, equipped with a microsilica column in the first dimension in a combination to a cellulosic‐based chiral column used in the second dimension. The normal phase‐liquid chromatography‐liquid chromatography (NP‐LC‐LC) instrumentation was equipped with a photodiode array detector and a multiport valve as interface. For method optimization and the determination of absolute configuration, natural compounds were isolated and racemic mixture was synthesized. The NP‐LC‐LC/PDA (where PDA is photodiode array) method provided a good baseline separation of chiral coumarins (meranzin and epoxyaurapten) and furocoumarins (epoxybergamottin and byakangelicol) present in cold‐pressed Citrus essential oils without any sample pretreatment. Results obtained showed that for all the chiral compounds present in Citrus essential oils analyzed, there is always a clear prevalence of one of the two enantiomers, and do not appear influenced by the different geographical origin of the oils.
Two‐dimensional chromatography applied to the study of the thermo‐oxidative degradation of poly(styrene‐b‐butadiene) star block copolymers
Authors: Moyses Stephan
Published: July 2012

Two‐dimensional chromatography with gradient polymer elution chromatography in the first dimension and gel permeation chromatography in the second dimension was used to characterize a poly(styrene‐b‐butadiene) star block copolymer. The data evidence several populations that are clues left by the different steps in the sequential reaction employed to make the polymer. The sample was subjected to thermo‐oxidative degradation at 180°C and was analyzed at different times during the process. After a relatively long induction period, the two‐dimensional chromatograms show how the different populations are progressively degraded via random chain scission of the polybutadiene block to leave essentially polystyrene as the only soluble component. With longer thermal aging times, the polystyrene also degrades via chain scission.
Chromatographic resolution and isotherm determination of (R,S)‐mandelic acid on Chiralcel‐OD column
Authors: Mao Shimin , Zhang Yan , Rohani Sohrab , Ray Ajay K.
Published: July 2012

Resolution of racemic mandelic acid ((R,S)‐MA) and numerical determination of binary competitive isotherm of (R,S)‐MA on Chiralcel‐OD column have been investigated in this study. The effects of the alcohol modifier and acidic additive in the mobile phase on the retention and enantioseparation of (R,S)‐MA were studied at first. The inverse method was then used to determine the competitive isotherm parameters of (R,S)‐MA by minimizing the sum of square deviations of the model predictions from the measured elution profiles. The results indicate that the mobile phase with 85% hexane/15% isopropanol/0.3% trifluoroacetic acid mixture gives the best resolution of (R,S)‐MA and competitive‐modified Langmuir isotherm provides the more accurate sorption mechanism of (R,S)‐MA on the cellulose tris(3,5‐dimethylphenylcarbamate) chiral stationary phase.
Is DSM‐IV criterion A2 associated with PTSD diagnosis and symptom severity?
Authors: Osei‐Bonsu Princess E. , Spiro Avron , Schultz Mark R. , Ryabchenko Karen A. , Smith Eric , Herz Lawrence , Eisen Susan V.
Published: July 2012

The diagnostic criteria for posttraumatic stress disorder (PTSD) have received significant scrutiny. Several studies have investigated the utility of Criterion A2, the subjective emotional response to a traumatic event. The American Psychiatric Association (APA) has proposed elimination of A2 from the PTSD diagnostic criteria for DSM‐5; however, there is mixed support for this recommendation and few studies have examined A2 in samples at high risk for PTSD such as veterans. In the current study of 908 veterans who screened positive for a traumatic event, A2 was not significantly associated with having been told by a doctor that the veteran had PTSD. Those who endorsed A2, however, reported greater PTSD symptom severity in the 3 DSM‐IV symptom clusters of reexperiencing (d = 0.45), avoidance (d = 0.61), and hyperarousal (d = 0.44), and A2 was significantly associated with PTSD symptom severity for all 3 clusters (R2 = .25, .25, and .27, respectively) even with trauma exposure in the model. Thus, although A2 may not be a necessary criterion for PTSD diagnosis, its association with PTSD symptom severity warrants further exploration of its utility.
Preparation of AB2 Monomers and the Corresponding Hyperbranched Polyureas in a One‐Pot Procedure
Authors: Xiang Fei , Loontjens Ton , Geladé Erik , Vorenkamp Joop
Published: July 2012

Novel AB2 monomers and corresponding hyperbranched polyureas are prepared in a one‐pot process. AB2 monomers are synthesized by a highly selective reaction of carbonyl biscaprolactam (CBC) with triamines comprising one secondary and two primary amino groups. Only the primary amines react with CBC, yielding blocked isocyanates. On heating, self‐condensation of the obtained monomer solution takes place, yielding polymers with Mn up to 11 000 Da. Mark‐Houwink exponents of 0.3 and branching frequencies of 0.3 demonstrate the hyperbranched topology. Each polymer molecule comprises one secondary amino group in the focal point and numerous active blocked isocyanates located at the end of the polymer branches. The polymers are fully characterized by means of 1H NMR, 13C NMR, MALDI‐TOF, SEC, and DSC.
One‐Step Electrodeposition to Layer‐by‐Layer Graphene–Conducting‐Polymer Hybrid Films
Authors: Tang Yanhong , Wu Na , Luo Shenglian , Liu Chengbin , Wang Ke , Chen Liuyun
Published: July 2012

One‐step fabrication of graphene–polyaniline (graphene–PANI) hybrid film was facilely achieved by cyclic voltammetric electrolysis of a bath containing both graphene oxide (GO) and aniline, where graphene is obtained by electrochemical reduction of GO and PANI is simultaneously obtained by aniline electropolymerization. As there is no strong attraction between aniline and GO under the electrodeposition conditions, the independent depositions of PANI and reduced GO nanosheets at their greatly differed potentials led to alternate layered graphene–PANI films, with the topmost layer being PANI particles or graphene sheets just by changing the initial scan directions. The two kinds of graphene–PANI hybrid films present excellent but different electrical and electrochemical behaviors.
Reconstruction of lower extremity complex wounds with combined free tissue transfer using the anterolateral thigh flap as a link
Authors: Kim Tae‐Gon , Kim Il‐Kug , Kim Yong‐Ha , Lee Jun‐Ho
Published: July 2012

In this report, the authors present the experience on the reconstruction of the totally degloved foot and extremely long soft tissue defect of a lower limb with the combined free tissue transfer using the anterolateral thigh flap as a link in two male patients between October 2009 and December 2010. The anterolateral thigh flap has been commonly used as a link between the recipient site and the distal flap. The anterolateral thigh flap and latissimus dorsi muscle flap were selected for the distal flap, according to their reconstructive needs. Two combined free flaps survived without major complication. The authors could salvage of the lower extremity through the reconstruction of complex wound with the combined free tissue transfer using the anterolateral thigh flap as a link. This combined flap may be an alternative for reconstruction of complex soft tissue defect in the lower extremity. © 2012 Wiley Periodicals, Inc. Microsurgery, 2012.
Auricle reconstruction with a radial forearm flap prelaminated with porous polyethylene (Medpor®) implant
Authors: Simsek Tekin , Eroglu Lutfi
Published: July 2012

Severe auricular traumas with extensive involvement of the surrounding structures present with a serious defect necessitating free tissue transfers for reconstruction. In this case report, we present a case of whole left auricle reconstruction with a radial forearm flap prelaminated with porous polyethylene (Medpor®) implant in a 17‐year‐old female patient. First, a subdermal pouch was fashioned on the volar aspect of the left forearm along the projection of the radial artery and the Medpor implant was placed in this pouch. Four weeks later, the prelaminated radial forearm flap containing the Medpor implant was transferred to the recipient site. Resultant construct had a pliable skin cover, and the patient was pleased with the esthetic outcome even though revisions such as external auditory meatus widening, conchal cup deepening, and lobule defining were planned as further interventions. We believe that this method is a pertinent reconstructive option for extensive defects of the auricular region. © 2012 Wiley Periodicals, Inc. Microsurgery, 2012.
Application of singularity expansion method for monitoring the deployment of arterial stents
Authors: Manteghi Majid , Cooper Daniel B. , Vlachos Pavlos P.
Published: July 2012

A stent is a metal tube used to treat blocked blood vessels in the body. The stent is deployed into obstructed part of the blood vessel to keep it open and improve the blood flow in the diseased area. During the stent implantation, the collapsed stent is expanded into the artery to a size so as to stick to the artery walls. Because of the significant health dangers caused by the over‐expansion or under‐expansion of the stent, having a proper estimation of diameter of the stent in the artery during expansion is important. However, yet to date, no method exists that would allow real time monitoring during and after the stent expansion process. In this article, we present a novel methodology to estimate diameter of the stent during and after deployment in the artery by applying the singularity expansion method (SEM). According to SEM, the transient electromagnetic signal scattered from bodies can be described by poles and residues. Poles are intrinsic property of the body that can be used to detect deformation of an object such as expansion. We have demonstrated the idea of estimating diameter of a stent via tracking poles by both simulation and measurement. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2241–2246, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27053
Gigabyte and terabyte per second connections with semiconductor waveguide technology
Authors: Magri Vanessa P. R. , Lima Rodolfo A. A. , Mosso Marbey M.
Published: July 2012

This work presents the research, design, and development of guided‐wave connections in SiGe semiconductor substrates.The integration of digital systems using semiconductor integrated waveguides (S‐SIWG) with QAM modulation formats are highlighted for ultrafast inter‐chip and intra‐chip connections at 100 Gbit/s extended to the Terahertz domain. The simulations of the frequency response for the prototype model with coaxial probe excitations in the frequency range 50–150 GHz are evaluated, showing far than satisfactory performance. The S‐SIWG is then simulated in the 0.5–1.5 THz bandwidth, presenting excellent insertion loss. A SiGe S‐SIWG prototype was fabricated and tested at 15–60 GHz. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2438–2444, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27060
Circularly polarized slotted‐ground microstrip antennas for radiofrequency identification readers
Authors: Randy Oktavinus Tanawie , Nasimuddin  , Alphones Arokiaswami
Published: July 2012

The single‐feed, circularly polarized microstrip antennas (CPMAs) based on the slotted‐ground plane are investigated for radiofrequency identification readers.The conventional CPMA with truncated corners is also studied to compare with the proposed CPMA's performances. In the proposed designs, four square slots with asymmetrical configuration are etched in the diagonal directions on the ground plane of the antenna to achieve circularly polarized radiation. The proposed CPMAs are designed with low‐cost FR4 substrate and RO4003C substrate and their performances are compared. The antenna bandwidth is also studied on thin and thick dielectric substrates. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2304–2309, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27075
Pulse width and peak power optimization in a mode‐locked fiber laser with a semiconductor saturable absorber mirror
Authors: Cho Seung Bum , Song Hoseong , Gee Sangyoun , Park Chang‐Soo , Kim Dug Young
Published: July 2012

In this comprehensive study, we report on the pulse characteristics of a mode‐locked fiber laser comprised of an ytterbium (Yb)‐doped fiber and a semiconductor saturable absorber mirror (SESAM). We show experimentally that the pulse width and peak power of a mode‐locked fiber laser were continuously changed by moving the axial position of the SESAM in the laser cavity. The principle of this pulse width adjustment is explained and demonstrated with a simple numerical simulation. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2256–2261, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27077
Millimeter‐wave miniaturized hybrid couplers integrated on advanced bicmos technology
Authors: Titz Diane , Ferrero Fabien , Debroucke Romain , Pilard Romain , Luxey Cyril , Gianesello Frédéric , Jan Sébastien , Gloria Daniel , Jacquemod Gilles
Published: July 2012

In this article, we present the design and the measurement of two hybrid couplers for millimeter‐wave applications realized in the BiCMOS9MW 130nm process (ST Microelectronics). The aim is to demonstrate several miniaturization possibilities of a conventional branchline coupler while maintaining a constant 90° phase shift and a low insertion loss over the full 57–66‐GHz band. The first miniaturized coupler is composed of meandered transmission lines; the second is a quasi‐lumped quadrature coupler with discrete capacitors. The performance of these circuits is compared with the most recent on‐chip 60‐GHz couplers. We especially demonstrate the possibility to achieve state‐of‐the‐art performance while using miniaturization techniques. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2221–2223, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27079
UWB monopole microstrip antenna using fractal tree unit‐cells
Authors: Naser‐Moghadasi M. , Sadeghzadeh R.A. , Aribi T. , Sedghi T. , Virdee B. S.
Published: July 2012

This article presents the design of a novel and compact ultra‐wideband fractal‐based monopole antenna. Enhancement of the antenna's bandwidth is achieved by increasing the unit‐cells of the fractal tree without significantly impacting on the antenna's physical size. The actual size of the miniature antenna is limited to 24 × 24 × 1 mm3 and it operates across 2.1–11.52 GHz for VSWR ≤ 2. The proposed fractal structure makes the antenna flexible in terms of resonance and bandwidth control, which is a function of iteration order of the fractal used. The efficiency of the prototype antennas fabricated was evaluated through simulations and measurements. The measured results confirm the antenna radiates omnidirectionally and has a large impedance bandwidth. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2366–2370, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27081
A low‐chip area and low‐phase noise hybrid phase‐locked loop
Authors: Huang Jhin‐Fang , Hsu Chien‐Ming , Chen Kuo‐Lung
Published: July 2012

A low‐chip area and low‐phase noise phase‐locked loop (PLL) combining fractional‐N and integer‐N modes operating at 2.4 GHz band is proposed and fabricated in TSMC 0.18‐μm CMOS process.The proposed PLL with a Gm‐boosted Colpitts voltage‐controlled oscillator improves phase noise and a hybrid design of different divider loops achieves fast lock. At 1.8 V supply voltage, the proposed PLL shows a wide tuning range from 2.14 to 2.36 GHz, corresponding to 9.7%, a phase noise of −119.3 dBc/Hz at an offset frequency of 1 MHz from the carrier frequency of 2.14 GHz, a power consumption of 17.3 mW, and an output power of −15.37 dBm. Including pads, the chip area only occupies 0.588 (0.87 × 0.67) mm2. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2295–2300, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27082
All‐optical OOK‐to‐QAM modulation format conversion utilizing parallel SOA‐MZI wavelength converters
Authors: Turkiewicz Jarosław Piotr
Published: July 2012

A novel all‐optical modulation format conversion scheme from on‐off keying to quadrature amplitude modulation (QAM) utilizing wavelength conversion in the semiconductor optical amplifier Mach–Zehnder Interferometers is proposed. The numerical simulations show generation of the 16‐QAM signal proofing the principle of the proposed concept and its utility in future telecommunication systems. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2429–2433, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27084
A compact wideband CMOS LNA with low power consumption
Authors: Jang Yohan , Choi Jaehoon
Published: July 2012

In this letter, a wideband low noise amplifier (LNA) operating at 1–5 GHz is proposed.The circuit is designed with a TSMC 0.18‐μm RF CMOS process. To obtain high transconductance with low power consumption, two types of inverters are used. The proposed LNA is expected to reduce the size of chip about 70–80% by using only the single‐spiral inductor. The measured voltage gain is 14.4–15.5 dB and noise figure (NF) is 4.3–5.0 dB from 1–5 GHz. The total power consumption of the proposed LNA is 9.8 mW from a 1.4 V supply voltage and chip area occupies only 0.5 × 0.5 mm2. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2360–2363, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27086
Design of high efficiency RF‐DC conversion circuit using novel termination networks for RF energy harvesting system
Authors: Chaudhary Girdhari , Kim Phirun , Jeong Yongchae , Yoon Jae‐Hun
Published: July 2012

In this letter, a high efficiency RF‐DC conversion circuit for RF energy harvesting system (EHS) is proposed.The proposed circuit consists of Villard voltage doubler, the input and output termination networks which can suppress the unwanted RF signals produced by Schottky diodes. The fabricated circuit operating at 2.45 GHz has a maximum RF‐DC conversion efficiency of 83.37% and output voltage of 11.30 V at an input RF power of 140 mW. The proposed circuit has an advantage of simple design which helps to reduce the design cost of EHSs. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2330–2335, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27087
Embedded multislotted PIFAs for remotely powered passive UHF RFID tags
Authors: Contopanagos Harry F. , Broutas Panayotis , Chatzandroulis Stavros
Published: July 2012

We present a compact planar antenna that can be embedded within low‐frequency UHF power‐harvesting tag platforms.The antenna is a planar inverted‐F antenna‐type design with a set of optimized slots and provides large bandwidths, comparable to half‐wave dipoles, while maintaining a low profile and small area. Hence, it can be embedded within the PCB of power‐harvesting tags operating even at low UHF frequencies, resulting in a compact, slim overall device. We demonstrate this by embedding the antenna within a 430 MHz low‐power discrete‐component harvester tag, and we have designed and manufactured and verified antenna performance by both antenna measurements and tag link measurements. An added advantage of this topology is that tags with this antenna can be placed very near large metal structures without shorting or detuning, unlike tags with standard external dipole antennas. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2379–2383, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27096
Inversion of 1JCC correlations in 1,n‐ADEQUATE spectra
Authors: Martin Gary E. , Williamson R. Thomas , Dormer Peter G. , Bermel Wolfgang
Published: July 2012

ADEQUATE experiments provide an alternative to the more commonly employed GHMBC experiment for the establishment of long‐range heteronuclear connectivities. The 1,1‐ADEQUATE experiment allows the unequivocal identification of both protonated and non‐protonated carbon resonances adjacent to a protonated carbon. The 1,n‐ADEQUATE experiment establishes correlations via an initial 1JCH heteronuclear transfer followed by an nJCC out‐and‐back transfer, most typically, via three carbon–carbon bonds. Hence, the 1,n‐ADEQUATE experiment allows the equivalent of 4JCH heteronuclear correlations to be probed when they are not observed in a GHMBC spectrum. Aside from the lower sensitivity of the 1,n‐ADEQUATE experiment relative to GHMBC experiments, the interpretation of the former is also complicated by the ‘leakage’ of 1JCC correlations into the spectrum that must be identified. A method for the inversion of 1JCC correlations to facilitate the interpretation of 1,n‐ADEQUATE spectra is presented that allows a single experiment to be performed to access 1JCC and nJCC correlation information. Copyright © 2012 John Wiley & Sons, Ltd.
Quantitative neuromuscular ultrasound in the intensive care unit
Authors: Cartwright Michael S. , Kwayisi Golda , Griffin Leah P. , Sarwal Aarti , Walker Francis O. , Harris Jessica M. , Berry Michael J. , Chahal Preet S. , Morris Peter E.
Published: July 2012

Introduction: Intensive care unit acquired weakness (ICU‐AW) results from a complex mixture of nerve and muscle pathology, and early identification is challenging. This pilot study was designed to examine the ultrasonographic changes that occur in muscles during ICU hospitalization. Methods: Patients admitted to the ICU for acute respiratory failure were enrolled prospectively and underwent serial muscle ultrasound for thickness and gray‐scale assessment of the tibialis anterior, rectus femoris, abductor digiti minimi, biceps, and diaphragm muscles over 14 days. Results: Sixteen participants were enrolled. The tibialis anterior (P = 0.001) and rectus femoris (P = 0.041) had significant decreases in gray‐scale standard deviation when analyzed over 14 days. No muscles showed significant changes in thickness. Conclusions: Ultrasound is an informative technique for assessing muscles of patients in the ICU, and lower extremity muscles demonstrated increased homogeneity during ICU stays. This technique should be examined further for diagnosing and tracking those with ICU‐AW. Muscle Nerve, 2013
In vivo MRS and histochemistry of status epilepticus‐induced hippocampal pathology in a juvenile model of temporal lobe epilepsy
Authors: van der Hel W. Saskia , van Eijsden Pieter , Bos Ineke W. M. , de Graaf Robin A. , Behar Kevin L. , van Nieuwenhuizen Onno , de Graan Pierre N. E. , Braun Kees P. J.
Published: July 2012

Childhood status epilepticus (SE) initiates an epileptogenic process that leads to spontaneous seizures and hippocampal pathology characterized by neuronal loss, gliosis and an imbalance between excitatory and inhibitory neurotransmission. It remains unclear whether these changes are a cause or consequence of chronic epilepsy. In this study, in vivo MRS was used in a post‐SE juvenile rat model of temporal lobe epilepsy (TLE) to establish the temporal evolution of hippocampal injury and neurotransmitter imbalance. SE was induced in P21 rats by injection of lithium and pilocarpine. Four and eight weeks after SE, in vivo 1H and γ‐aminobutyric acid (GABA)‐edited MRS of the hippocampus was performed in combination with dedicated ex vivo immunohistochemistry for the interpretation and validation of MRS findings. MRS showed a 12% decrease (p < 0.0001) in N‐acetylaspartate and a 15% increase (p = 0.0226) in choline‐containing compound concentrations, indicating neuronal death and gliosis, respectively. These results were confirmed by FluoroJade and vimentin staining. Furthermore, severe and progressive decreases in GABA (−41%, p < 0.001) and glutamate (Glu) (−17%, p < 0.001) were found. The specific severity of GABAergic cell death was confirmed by parvalbumin immunoreactivity (−68%, p < 0.001). Unexpectedly, we found changes in glutamine (Gln), the metabolic precursor of both GABA and Glu. Gln increased at 4 weeks (+36%, p < 0.001), but returned to control levels at 8 weeks. This decrease was consistent with the simultaneous decrease in glutamine synthase immunoreactivity (−32%, p = 0.037). In vivo MRS showed gliosis and (predominantly GABAergic) neuronal loss. In addition, an increase in Gln was detected, accompanied by a decrease in glutamine synthase immunoreactivity. This may reflect glutamine synthase downregulation in order to normalize Gln levels. These changes occurred before spontaneous recurrent seizures were present but, by creating a pre‐epileptic state, may play a role in epileptogenesis. MRS can be applied in a clinical setting and may be used as a noninvasive tool to monitor the development of TLE. Copyright © 2012 John Wiley & Sons, Ltd.
Min‐Max quickest path problems
Authors: Ruzika Stefan , Thiemann Markus
Published: July 2012

In a dynamic network, the quickest path problem asks for a path such that a given amount of flow can be sent from source to sink via this path in minimal time. In practical settings, for example, in evacuation or transportation planning, the problem parameters might not be known exactly a priori. It is therefore of interest to consider robust versions of these problems in which travel times and/or capacities of arcs depend on a certain scenario. In this article, min–max versions of robust quickest path problems are investigated and, depending on their complexity status, exact algorithms or fully polynomial‐time approximation schemes are proposed. © 2012 Wiley Periodicals, Inc. NETWORKS, 2012
Linearly many faults in arrangement graphs
Authors: Cheng Eddie , Lipták László , Yuan Allen
Published: July 2012

The star graph proposed by Akers et al. (Proc Int Conf Parallel Process, University Park, PA, 1987, pp. 393–400) has many advantages over the n‐cube. However, it suffers from having large gaps in the possible number of vertices. The arrangement graph was proposed by Day and Tripathi (Inf Process Lett 42 (1992), 235–241) to address this issue. Since it is a generalization of the star graph, it retains many of the nice properties of the star graph. In fact, it also generalizes the alternating group graph (Jwo et al., Networks 23 (1993), 315–326). There are many different measures of structural integrity of interconnection networks. In this article, we prove results of the following type for the arrangement graph: If h(r,n,k) vertices are deleted from the arrangement graph An,k, the resulting graph will either be connected or have a large component and small components having at most r − 1 vertices in total. Our result is tight for r ≤ 3, and it is asymptotically tight for r ≥ 4. Moreover, we also determine the cyclic vertex‐connectivity of the arrangement graph. © 2012 Wiley Periodicals, Inc. NETWORKS, 2013
New liquid crystalline columnar poly(epichlorohydrin‐co‐ethylene oxide) derivatives leading to biomimetic ion channels
Authors: Bhosale Suryakant Vilasrao , Rasool Muhammad Azam , Reina José Antonio , Giamberini Marta
Published: July 2012

A new family of liquid crystalline columnar polyethers was obtained by modification of Poly(epichlorohydrin‐co‐ethylene oxide) (P(ECH‐co‐EO)) with the dendron 3,4,5‐tris[4‐(n‐dodecan‐1‐yloxy)benzyloxy]benzoate, under different conditions. The highest modification degree that we could achieve was 69%. The copolymers were fully characterized by 1H and 13C nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), polarized optical microscopy (POM), and X‐ray diffraction (XRD). All copolymers exhibited liquid‐crystalline columnar behavior whose range of stability depended on the modification degree. X‐ray diffraction experiments on oriented samples showed that the dendrons are approximately perpendicular to the column axis and that their average number per unit cell ranged from 5 to 6. The formation of a stable columnar mesophase in the polyether should determine the presence of a continuous ion channel along the column axis. Therefore, these copolymers are suitable candidates for the preparation of membranes for small cation transport, in agreement with the results that we obtained by using poly(oxy‐1‐chloro methylethylene) (PECH) modified with the same dendron. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
Fabrication and applications of cellulose nanoparticle‐based polymer composites
Authors: Pandey Jitendra K. , Nakagaito Antonio N. , Takagi Hitoshi
Published: July 2012

The impressive mechanical properties, reinforcing capability, abundance, low weight, low filler load requirements, and biodegradable nature of nanoparticles from bioresources such as cellulose, make it an ideal candidate for the development of green polymer nanocomposites. Significant amount of research in this area is primarily focused on the extraction, qualitative surface modification, and evaluation of mechanical performance after filling in polymer matrixes at different ratios. The extreme agglomeration tendency, hydrophilic nature, difficult dispersion in many organic solvents of cellulose nanoparticles are the challenging obstacles when fabrication of such nanocomposites is concerned. Traditional processing of polymer composites mainly through extrusion and melt compounding, is not easily possible in case of cellulose nanocomposites due to higher possibility of poor dispersion and degradation of nanofibers. Therefore, issues related to the fabrication of nanofiber‐based products and their application appears to be one of the most important areas in order to enhance their competitiveness with other nanoparticles. This review is aimed to summarize the recent accomplishments and issues involving the use of cellulose nanoparticles in the development of new polymeric materials. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
Assessment of intertube interactions in different functionalized multiwalled carbon nanotubes incorporated in a phenoxy resin
Authors: Disfani Mahdi Najjar , Jafari Seyed‐Hassan
Published: July 2012

In this work, about 1 wt% of different functionalized carbon nanotubes (CNTs), namely CNTCOOH (CNT with carboxylic groups), CNTNH2 (CNT with amine groups) and CNTOH (CNT with hydroxyl groups), as well as nonfunctionalized CNTs were incorporated into a phenoxy resin via a melt mixing process. The extent of intertubes and polymer–tubes interactions and their influence on state of CNTs dispersion were assessed through determination of electrical, rheological, and morphological characteristics. CNTNH2 showed the lowest intertubes interactions followed by CNTOH and CNTCOOH. Nanocomposite made from CNTCOOH showed the poorest state of CNTs dispersion and the biggest CNTs agglomerates and it remained nonconductive. The acid‐functionalized CNTs were not able to form strong polymer–tube interactions because of their high cohesive energy and therefore in the melt rheological investigations they exhibited the lowest storage modulus and complex viscosity as well as the highest loss factor among all the studied CNTs. A good balance between intertubes and polymer–tube interactions is necessary through proper selection of CNTs functional groups for achieving a good state of CNTs dispersion and consequently obtaining enhanced electrical and viscoelastic properties. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
Effect of crosslink density on the refractive index of a polysiloxane network based on 2,4,6,8‐tetramethyl‐2,4,6, 8‐tetravinylcyclotetrasiloxane
Authors: Tyng Looi Yien , Ramli Mohamad Riduwan , Othman Muhammad Bisyrul Hafi , Ramli Rafiza , Ishak Zainal Arifin Mohd , Ahmad Zulkifli
Published: July 2012

Crosslink density is one of the factors which dictate the optical and mechanical properties of silicone‐based polymers. A series of hydrosilyl‐terminated polydimethylsiloxane cured with 2,4,6,8‐tetramethyl‐2,4,6,8‐tetravinyl cyclotetrasiloxane was prepared to form a crosslink network. They were clear gel forms whose elastomeric features were dependent on the end‐capper concentration, 1,1,3,3‐tetramethyldisiloxane, employed during their synthesis. The siloxane‐based polymers displayed excellent thermal stability whose decomposition temperature was around 480 °C. The refractive index was in the range 1.410–1.425. It was found that the refractive index is dependent on the crosslink density of the network. The effect of fractional free volume and ‘densification’ of the network was elucidated and found to contribute to this dependence. The Lorentz–Lorenz model was used to integrate these observations. © 2012 Society of Chemical Industry
The course of positive affective and cognitive states in borderline personality disorder: A 10‐year follow‐up study
Authors: Reed Lawrence Ian , Fitzmaurice GARRETT , Zanarini MARY C.
Published: July 2012

The first aim of this study was to identify the course of positive states present in borderline personality disorder (BPD) and compare them with those of subjects with other personality disorders. The second was to compare the positive states of borderline patients who recovered from BPD with those who did not. Two hundred ninety patients with BPD and 72 non‐borderline axis II subjects (OPD) completed the Positive Affect Scale (PAS), a 50‐item self‐report measure designed to assess positive states thought to be common among and characteristic of BPD over a 10‐year course of prospective follow‐up. Affective, cognitive and mixed PAS items were separately analysed on the basis of respective subscores. Borderline patients reported positive states less frequently than OPD subjects. Additionally, affective and cognitive subscores increased significantly for both groups taken together. Within the BPD group, recovered patients reported more positive states compared with non‐recovered patients. Results also showed a significant increase in affective and cognitive states for both groups taken together. These results suggest a characteristic profile of positive states within borderline patients that is far lower than those reported by axis II comparison subjects. They also suggest that this characteristic profile is predictive of recovery of BPD over time. Copyright © 2012 John Wiley & Sons, Ltd.
Mechanistic insights into the hydrolysis of organophosphorus compounds by paraoxonase‐1: exploring the limits of substrate tolerance in a promiscuous enzyme
Authors: Muthukrishnan Sivaramakrishnan , Shete Vivekanand S. , Sanan Toby T. , Vyas Shubham , Oottikkal Shameema , Porter Lauren M. , Magliery Thomas J. , Hadad Christopher M.
Published: July 2012

We designed, synthesized, and screened a library of analogs of the organophosphate pesticide metabolite paraoxon against a recombinant variant of human serum paraoxonase‐1. Alterations of both the aryloxy leaving group and the retained alkyl chains of paraoxon analogs resulted in substantial changes to binding and hydrolysis, as measured directly by spectrophotometric methods or in competition experiments with paraoxon. Increases or decreases in the steric bulk of the retained groups generally reduced the rate of hydrolysis, while modifications of the leaving group modulated both binding and turnover. Studies on the hydrolysis of phosphoryl azide analogs as well as amino‐modified paraoxon analogs, the former being developed as photoaffinity labels, found enhanced tolerance of structural modifications when compared with O‐alkyl‐substituted molecules. Results from computational modeling predict a predominant active site binding mode for these molecules, which is consistent with several proposed catalytic mechanisms in the literature and from which a molecular‐level explanation of the experimental trends is attempted. Overall, the results of this study suggest that while paraoxonase‐1 is a promiscuous enzyme, there are substantial constraints in the active site pocket, which may relate to both the leaving group and the retained portion of paraoxon analogs. Copyright © 2012 John Wiley & Sons, Ltd.