bluuebunny/crossref_metadata_2025 huggingface dataset:
High‐performance liquid chromatography tandem mass spectrometry method for the determination of 2CC‐NBOMe and 25I‐NBOMe in human serum
Authors: Poklis Justin L. , Charles Jezelle , Wolf Carl E. , Poklis Alphonse
Published: July 2013

2CC‐NBOMe {4‐chloro‐2,5‐dimethoxyphenethyl‐N‐[(2‐methoxyphenyl) methyl] ethanamine} and 25I‐NBOMe {2‐(4‐iodo‐2,5‐dimethoxyphenyl)‐N‐[(2‐methoxyphenyl) methyl] ethanamine} are of a class of N‐benzyl phenethylamine derivatives whose synthesis was first reported in the scientific literature in 2011. Recent reports from ‘personal drug experience websites’ and in the popular press indicate these drugs are the latest in a series of designer ‘Bath Salt’ drugs of abuse. The presented high‐performance liquid chromatography triple quadrupole mass spectrometry (HPLC/MS/MS) method was developed for the detection and quantification of 2CC‐NBOMe and 25I‐NBOMe in serum of intoxicated emergency department patients. The assay applies 2‐​(2,​5‐​dimethoxyphenyl)‐​N‐​(2‐​methoxybenzyl) ethanamine (25H‐NBOMe) as the internal standard. Samples were extracted using solid‐phase extraction columns. The chromatographic separation was performed on a Luna 3 µ C8(2) 100 Å, 100 × 2.0 mm, column. Detection was accomplished by multiple‐reaction monitoring via an electrospray ionization source operating in the positive ionization mode. The calibration curves were linear over the investigated concentration range, 30–2000 pg/mL, with a lower limit of detection of 10 pg/mL for both 2CC‐NBOMe and 25I‐NBOMe. The method proved suitable for serum clinical toxicology testing. Two severely intoxicated emergency department patients were determined to have serum concentrations of 250 and 2780 pg/mL of 25I‐NBOMe using the presented method. Copyright © 2013 John Wiley & Sons, Ltd.
Pharmacokinetic and tissue distribution of paclitaxel in rabbits assayed by LC‐UV after intravenous administration of its novel liposomal formulation
Authors: Wei Yumeng , Xue Zhengkai , Ye Yun , Wang Peng , Huang Yu , Zhao Ling
Published: July 2013

A simple, rapid and sensitive LC‐UV method was developed and validated for the determination of paclitaxel (PTX) in rabbit plasma and tissues. A 2 mL aliquot of acetonitrile and 10 μL ammonium acetate (pH 5.0, 6 m) as extraction agents were used to markedly increase the extraction recoveries and greatly reduce the endogenous substances. The separation was achieved on a C18 column at 30 °C using an acetonitrile–ammonium acetate buffer (pH 5.0, 0.02 m; 55:45, v/v) at a flow rate of 1.0 mL/min; UV detection was used at 227 nm. Good linearity was obtained between 0.025 and 10,000 µg/mL for plasma and between 0.025–200,000 µg/g for tissue samples (r > 0.999). The limit of detection was 6 ng/mL in plasma, 8 ng/g in heart and 12.5 ng/g in other tissues. The limit of quantitation was 25 ng/mL in plasma and heart, 125 ng/g in other tissues. The intra‐ and inter‐day assays of precision and accuracy for all bio‐samples ranged from 1.38 to 9.60% and from 83.6 to 114.5%, respectively. The extraction recoveries ranged from 70.1 to 109.5%. Samples were stable during three freeze–thaw cycles or stored in a freezer at −20 °C for 30 days. The assay method was successfully applied to a study of the pharmacokinetics and tissue distribution of novel PTX lung targeting liposomes. Copyright © 2013 John Wiley & Sons, Ltd.
Adaptive sampling for performance characterization of application kernels
Authors: de Oliveira Castro Pablo , Petit Eric , Farjallah Asma , Jalby William
Published: July 2013

Characterizing performance is essential to optimize programs and architectures. The open source Adaptive Sampling Kit (ASK) measures the performance trade‐off in large design spaces. Exhaustively sampling all sets of parameters is computationally intractable. Therefore, ASK concentrates exploration in the most irregular regions of the design space through multiple adaptive sampling strategies. The paper presents the ASK architecture and a set of adaptive sampling strategies, including a new approach called Hierarchical Variance Sampling. ASK's usage is demonstrated on three performance characterization problems: memory stride accesses, Jacobian stencil code, and an industrial seismic application using 3D stencils. ASK builds accurate models of performance with a small number of measures. It considerably reduces the cost of performance exploration. For instance, the Jacobian stencil code design space, which has more than 31 × 108 combinations of parameters, is accurately predicted using only 1500 combinations. Copyright © 2013 John Wiley & Sons, Ltd.
Periodic variation method for blind symbol rate estimation
Authors: Güner Ahmet , Kaya Ismail
Published: July 2013

In order to obtain unknown symbol rate of incoming signal at a receiver, in this paper, cyclostationary features of linear digitally modulated signals are exploited by proposed periodic variation method. A low complexity but highly accurate symbol rate estimation technique is obtained. The proposed method is based on a superposed epoch analysis over autocorrelations obtained blindly in different sampling frequencies. The obtained autocorrelations are analyzed in the frequency domain, and it is seen that there are large oscillations when the autocorrelation is obtained around the symbol rate. Then, a superposed epoch analysis is developed in order to estimate symbol rate based of the periodic variations on the frequency responses of autocorrelations. The proposed algorithm is quite accurate in the noisy environment because the noise is having no frequency component after taking Fourier transform of autocorrelations in all sampling rates, and this feature is also valid for the offset frequency that the purposed estimation is not affected by offset frequency. Thus, a successful blind symbol rate estimation algorithm is obtained, and it performs much better error performance than those using the well‐known cyclic correlation based symbol rate estimations, as it is proven by the obtained performances presented in the paper. Copyright © 2013 John Wiley & Sons, Ltd.
Modeling of misalignment effects in microfluidic interconnects for modular bio‐analytical chip applications
Authors: Rani Sudheer D. , Park Taehyun , You Byoung Hee , Soper Steve A. , Murphy Michael C. , Nikitopoulos Dimitris E.
Published: July 2013

Minimizing misalignments during the interconnection of microfluidic modules is extremely critical to develop a fully integrated microfluidic device. Misalignments arising during chip‐to‐chip or world‐to‐chip interconnections can be greatly detrimental to efficient functioning of microfluidic devices. To address this problem, we have performed numerical simulations to investigate the effect of misalignments arising in three types of interconnection methods: (i) end‐to‐end interconnection (ii) channel overlap when chips are stacked on top of each other, and (iii) tube‐in‐reservoir misalignment occurring due to the offset between the external tubing and the reservoir. For the case of end‐to‐end interconnection, the effect of misalignment was investigated for 0, 13, 50, 58, and 75% reduction in the available flow area at the location of geometrical misalignment. In the channel overlap interconnection method, various possible misalignment configurations were simulated by maintaining the same amount of misalignment (75% flow area reduction). The effect of misalignment in a tube‐in‐reservoir interconnection was investigated by positioning the tube at an offset of 164 μm from the reservoir center. All the results were evaluated in terms of the equivalent length of a straight pipe. The effect of Reynolds number (Re) was also taken into account by performing additional simulations of aforementioned cases at Re ranging between 0.075 ≤ Re ≤ 75. Correlations were developed and the results were interpreted in terms of equivalent length (Le). Equivalent length calculations revealed that the effect of misalignment in tube‐in‐reservoir interconnection method was the least significant when compared to the other two methods of interconnection.
Multiplex genotyping assays for fine‐resolution subtyping of the major human Y‐chromosome haplogroups E, G, I, J, and R in anthropological, genealogical, and forensic investigations
Authors: van Oven Mannis , Toscani Kimberley , van den Tempel Nathalie , Ralf Arwin , Kayser Manfred
Published: July 2013

Inherited DNA polymorphisms located within the nonrecombing portion of the human Y chromosome provide a powerful means of tracking the patrilineal ancestry of male individuals. Recently, we introduced an efficient genotyping method for the detection of the basal Y‐chromosome haplogroups A to T, as well as an additional method for the dissection of haplogroup O into its sublineages. To further extend the use of the Y chromosome as an evolutionary marker, we here introduce a set of genotyping assays for fine‐resolution subtyping of haplogroups E, G, I, J, and R, which make up the bulk of Western Eurasian and African Y chromosomes. The marker selection includes a total of 107 carefully selected bi‐allelic polymorphisms that were divided into eight hierarchically organized multiplex assays (two for haplogroup E, one for I, one for J, one for G, and three for R) based on the single‐base primer extension (SNaPshot) technology. Not only does our method allow for enhanced Y‐chromosome lineage discrimination, the more restricted geographic distribution of the subhaplogroups covered also enables more fine‐scaled estimations of patrilineal bio‐geographic origin. Supplementing our previous method for basal Y‐haplogroup detection, the currently introduced assays are thus expected to be of major relevance for future DNA studies targeting male‐specific ancestry for forensic, anthropological, and genealogical purposes.
Treatment of long‐term stored DNA—Comparison between different methods to obtain high‐quality material
Authors: de Almeida Máira Pedroso , do Nascimento Carlos Souza , Périssé Iuri Viotti , de Souza Duarte Marcio , Veroneze Renata , Facioni Guimarães Simone E.
Published: July 2013

Long‐term stored DNA can be sometimes the only source of genetic material of an organism that does not exist anymore, but a research interest still persists. However, there is a lack of information about useful methods to improve quality from such type of material. In this study, we compared four different protocols using DNA samples collected in 1998. Fresh DNA was also tested aiming to check the differences between these two material types. Sixteen samples of each DNA type treated with phenol‐chloroform with PEG 5.0%, silica‐gel membrane spin column, PEG 7.5%, and glass‐fiber matrix spin column were submitted to spectrophotometer measurements, electrophoresis, PCR, and RFLP‐PCR to assess the best method concerning yield, quality, and purity. Based on the results, purification with PEG 7.5% was considered the best method to treat aged DNA samples. In addition to the efficiency, this protocol has low cost. Analyzing the data, we also conclude that long‐term stored DNA may be considered a reliable and potential resource for future molecular studies.
Thermoanalytical and infrared spectroscopic investigations on wax samples of native Colombian bees living in different altitudes
Authors: Pinzón Fernando , Torres Alexandra , Hoffmann Wolfgang , Lamprecht Ingolf
Published: July 2013

Colombia exhibits an extraordinarily high species diversity of the subfamily Apinae (honeybees, bumblebees, stingless bees, orchid bees). This fact makes it worthwhile to look for beeswax as biological material produced by these insects and to prove possible applications in technique and human life. We examined for the first time waxes from pollen and honey pots, brood cells, and involucres of different species of the tribes Bombini, Meliponini, and Apini native to South America. Thermal analyses were carried out with a TA Instruments SDT‐Q600 and simultaneous differential scanning calorimetry/thermogravimetric analysis with dry nitrogen as purge gas. Temperature scans started at ambient temperature and went up to 120°C. A fourier transform infrared spectroscopy Prestige‐21 spectrometer was used to obtain infrared spectra of the waxes. Our results underline that thermal properties and IR spectra of waxes are more similar within the taxonomic groups than between them and are related to the altitude where bees live. This work contributes to the achievement of information that will serve to establish energy mechanisms used by these insects and to set up conservation strategies to protect them.
Theory of Mind in Eating Disorders and Their Relationship to Clinical Profile
Authors: Tapajóz Pereira de Sampaio Fernanda , Soneira Sebastian , Aulicino Alfredo , Allegri Ricardo F.
Published: July 2013

Objective

This study aimed to assess cognitive and affective theory of mind (ToM) in patients with eating disorders and to explore its relationship with the clinical and psychopathological profile.

Method

Theory of mind was assessed in 65 women, consisting of 22 with anorexia nervosa (AN), 19 with bulimia nervosa (BN), and 24 healthy controls (HC), using the Reading the Mind in the Eyes Test and the Faux Pas Test. These tasks evaluate affective and cognitive ToM, respectively. We also examined the correlations between performance on ToM tasks and the clinical psychopathological profile, which was extensively evaluated through self‐report instruments and clinical interviews.

Results

Patients with AN had poorer performance than BN patients and HCs had in the affective ToM task, particularly in recognizing negative emotions and emotions in male eyes. Moreover, this deficit showed no correlation with the psychopathological profile. Performance in the BN group was equivalent to that of HCs in both tasks.

Conclusions

In this study, patients with AN showed an impairment in affective ToM, independent of their clinical status. Consistent with other studies, our findings demonstrate a specific difficulty in social cognition in patients with AN. This may be a trait marker in this population and should be considered in treatment. Furthermore, patients with AN and BN have different difficulty profiles in this domain of social cognition. Copyright © 2013 John Wiley & Sons, Ltd and Eating Disorders Association.
Predicting concentrations of the cytostatic drugs cyclophosphamide, carboplatin, 5-fluorouracil, and capecitabine throughout the sewage effluents and surface waters of europe
Authors: Johnson Andrew C. , Oldenkamp Rik , Dumont Egon , Sumpter John P.
Published: July 2013

The present study evaluated the potential environmental concentrations of 4 cytostatic (also known as cytotoxic) drugs in rivers. The antimetabolite 5-fluorouracil (5FU) and its pro-drug capecitabine were examined based on their very high use rates, cyclophosphamide (CP) for its persistence, and carboplatin for its association with the metal element platinum. The study combined drug consumption information across European countries, excretion, national water use, and sewage removal rates to derive sewage effluent values across the continent. Results showed considerable variation in the popularity of individual cytostatic drugs across Europe, including a 28-fold difference in 5FU use and 15-fold difference in CP use. Such variations could have a major effect on the detection of these compounds in effluent or river water. Overall, capecitabine and CP had higher predicted levels in effluent than 5FU or carboplatin. Predicted effluent values were compared with measurements in the literature, and many non-detects could be explained by insufficient limits of detection. Linking the geographic based water resources model GWAVA with this information allowed water concentrations throughout 1.2 million km of European rivers to be predicted. The 90th percentile (worst case) prediction indicated that, with the exception of capecitabine, more than 99% of Europe's rivers (by length) would have concentrations below 1 ng/L for these cytostatic drugs. For capecitabine, 2.2% of river length could exceed 1 ng/L. Environ Toxicol Chem 2013;32:1954–1961. © 2013 SETAC
Predictors of mercury spatial patterns in San Francisco Bay forage fish
Authors: Greenfield Ben K. , Slotton Darell G. , Harrold Katherine H.
Published: July 2013

Pollution reduction efforts should be targeted toward those sources that result in the highest bioaccumulation. For mercury (Hg) in estuaries and other complex water bodies, carefully designed biosentinel monitoring programs can help identify predictors of bioaccumulation and inform management priorities for source reduction. This study employed a probabilistic forage fish Hg survey with hypothesis testing in San Francisco Bay (California, USA). The goal was to determine what pollution sources, regions, and landscape features were associated with elevated Hg bioaccumulation. Across 99 sites, whole-body Hg concentrations in Mississippi silversides (Menidia audens) and topsmelt (Atherinops affinis) followed a broad spatial gradient, declining with distance from the Guadalupe River (Pearson's r = –0.69 and –0.42, respectively), which drains historic mining areas. Site landscape attributes and local Hg sources had subtle effects, which differed between fish species. Topsmelt Hg increased in embayment sites (i.e., enclosed sites including channels, creek mouths, marinas, and coves) and sites with historic Hg-contaminated sediment, suggesting an influence of legacy industrial and mining contamination. In 2008, Mississippi silverside Hg was reduced at sites draining wastewater-treatment plants. Fish Hg was not related to abundance of surrounding wetland cover but was elevated in some watersheds draining from historic Hg-mining operations. Results indicated both regional and site-specific influences for Hg bioaccumulation in San Francisco Bay, including legacy contamination and proximity to treated wastewater discharge. Environ Toxicol Chem 2013;32:2728–2737. © 2013 SETAC
Biochemical and morphological responses in Chironomus riparius (Diptera, Chironomidae) larvae exposed to lead-spiked sediment
Authors: Arambourou Helene , Gismondi Eric , Branchu Philippe , Beisel Jean-Nicolas
Published: July 2013

The aim of the present study was to assess the potential use of biochemical markers and mentum deformities as indicators of long-term exposure to lead (Pb) in Chironomus riparius larvae. To do this, the authors measured 3 biochemical markers (i.e., malondialdehyde level, metallothionein concentration, and energy reserve content) as well as larval growth and mentum deformities after 16-d exposure to sediment containing Pb. The concentrations studied ranged from 3.5 mg/kg to 505.5 mg/kg dry weight. Despite the bioaccumulation of Pb in C. riparius bodies, frequencies of both mentum deformities and the dry weight were not significantly different between the control and stressed groups. On the contrary, Pb exposure caused a significant increase of both malondialdehyde level and metallothionein concentration. The increase of body Pb concentrations did not significantly modify body copper and zinc concentrations. Moreover, we observed a decrease of total lipid content and an increase of glycogen content as a function of a dose–response relationship, while no variation in protein concentrations was observed. Despite the adverse effects observed at the biochemical level, larval development was not affected. These results suggested that measurements of malondialdehyde level, metallothionein concentration, and energy reserve content can be used as relevant biomarkers of long-term sublethal exposure to Pb in C. riparius larvae. Environ Toxicol Chem 2013;32:2558–2564. © 2013 SETAC
Noxious or nutritious? Progress in controlling nitrate as a contaminant in leafy crop species
Authors: Weightman Richard M. , Hudson Elizabeth M.
Published: July 2013

High levels of nitrate in forage are a danger to the health of ruminant livestock consuming leafy crop species. Nitrate is also classed by food safety authorities as a contaminant in fresh produce. Since limits on nitrate levels in fresh produce marketed within the European Union were set, research has aimed to reduce nitrate, and to limit its variation. Progress is reported which focuses on the agronomy of a range of leafy salad crop species including lettuce (Lactuca sativa), spinach (Spinacea oleracea) and wild rocket (Diplotaxis tenuifolia). Genetic studies aiming to understand the sources of genetic variation in nitrate accumulation in lettuce are reviewed and considered in the context of research aiming to improve the nitrogen use efficiency of crop plants. Recent evidence is reported which suggests that nitrate could have significant health benefits that may contribute to the positive effects of eating a diet rich in fresh fruit and vegetables. Therefore, with the exception of babies and very young children, the risks from excess nitrate consumption are much greater for farm animals than they are for humans. Nevertheless, producers still need to carefully control nitrogen supply to leafy salad crops, to ensure that the risks of diffuse pollution from overuse of nitrogen fertilizer are minimized.
Treatment of depressive symptoms in diverse, rural, and vulnerable older adults
Authors: Scogin Forrest R. , Moss Kathryn , Harris Grant M. , Presnell Andrew H.
Published: July 2013

Background

We examined the effects of home‐delivered cognitive‐behavior therapy (CBT) on depressive symptoms among rural, diverse, and vulnerable older adults. Furthermore, we differentiated depression into its two salient aspects: psychological and somatic.

Method

Data came from a randomized controlled experiment of CBT on 134 individuals residing in rural Alabama.

Results

Cognitive‐behavior therapy resulted in significantly lower depressive symptom severity scores. When depressive symptoms were categorized as psychological or somatic, CBT was found to significantly improve the former but not the latter. Notably, there was a trend toward somatic symptom improvement.

Conclusion

Cognitive‐behavior therapy can be an effective treatment for depression in a hard‐to‐reach group of older adults. Home delivery affords advantages but is also an expensive delivery modality. Diverse older adults responded to the CBT intervention. Copyright © 2013 John Wiley & Sons, Ltd.
Advective timescales and pathways of Agulhas leakage
Authors: Rühs Siren , Durgadoo Jonathan V. , Behrens Erik , Biastoch Arne
Published: July 2013

Current research indicates an increase in Agulhas leakage for the past and coming decades. This change potentially alters the strength of the Atlantic meridional overturning circulation, in particular, through advection of positive density anomalies into the North Atlantic. To explore the fate of Agulhas leakage, results from a Lagrangian analysis were evaluated, with virtual floats advected within an eddy‐permitting ocean model (ORCA025). A considerable fraction of Agulhas leakage reached the subtropical North Atlantic: of a mean Agulhas leakage transport of 15.3 Sv entering the South Atlantic, 9.7, 7.7, and 6.1 Sv crossed sections at 6°S, 6°N, and 26°N, respectively. The most probable transit time of leakage to reach the respective latitudes is one to two decades. We suggest that changes in Agulhas leakage could manifest in the Gulf Stream regime most probably within two decades. These results were supported by an eddy‐resolving implementation of the ocean model (INALT01).
A Social Network Perspective on Turnover Intentions: The Role of Distributive Justice and Social Support
Authors: Soltis Scott M. , Agneessens Filip , Sasovova Zuzana , Labianca Giuseppe (Joe)
Published: July 2013

Organizations are increasingly concerned about retaining human talent, particularly within knowledge‐based industries where turnover is expensive. Our study employs a social network perspective to explore the influence of employees' formal and informal workplace relationships on their turnover intentions. We do this in a life sciences organization experiencing employee turnover at over twice the rate of the industry average. Drawing on extant work on the effects of distributive justice at work, we argue that employees who are heavily sought out for advice see themselves as being under‐rewarded for the time and effort that goes into providing advice, thus increasing turnover intentions. Additionally, we argue that employees see the ability to seek out advice as a form of social support that embeds them into the organization and decreases intention to quit. By exploring the network positions of individuals in the workflow and advice networks, we demonstrate that when employees are either providing advice to someone they are obligated to work with or are able to seek out advice from others who are not required to work with them, the relationship with turnover intentions is most intense. We conclude by discussing contributions to the theory and practice of human resource management.
Dynamic sonography and CT findings of unilateral submandibular gland agenesis associated with herniated hypertrophic sublingual gland
Authors: Yerli Hasan
Published: July 2013

Congenital agenesis of the submandibular gland is uncommon. We report dynamic sonography and CT findings of the unilateral submandibular gland agenesis associated with herniated hypertrophic sublingual gland tissue through the mylohyoid gap. The dynamic sonography examination applied at rest and during the modified Valsalva maneuver demonstrated hypertrophied sublingual gland prolapsing to the anterior part through the mylohyoid gap. This may be the first reported case describing dynamic sonography findings of this entity. CT confirmed the agenesis of the left submandibular gland and compensatory hypertrophy of the ipsilateral sublingual gland. © 2013 Wiley Periodicals, Inc. J Clin Ultrasound 42:176–179, 2014
Solar cycle modulation of Titan's ionosphere
Authors: Edberg N. J. T. , Andrews D. J. , Shebanits O. , Ågren K. , Wahlund J.‒E. , Opgenoorth H. J. , Cravens T. E. , Girazian Z.
Published: July 2013

During the six Cassini Titan flybys T83–T88 (May 2012 to November 2012) the electron density in the ionospheric peak region, as measured by the radio and plasma wave science instrument/Langmuir probe, has increased significantly, by 15–30%, compared to previous average. These measurements suggest that a long‒term change has occurred in the ionosphere of Titan, likely caused by the rise to the new solar maximum with increased EUV fluxes. We compare measurements from TA, TB, and T5, from the declining phase of solar cycle 23 to the recent T83–T88 measurements during cycle 24, since the solar irradiances from those two intervals are comparable. The peak electron densities normalized to a common solar zenith angle Nnorm from those two groups of flybys are comparable but increased compared to the solar minimum flybys (T16–T71). The integrated solar irradiance over the wavelengths 1–80nm, i.e., the solar energy flux, Fe, correlates well with the observed ionospheric peak density values. Chapman layer theory predicts that , with k=0.5. We find observationally that the exponent k=0.54±0.18. Hence, the observations are in good agreement with theory despite the fact that many assumptions in Chapman theory are violated. This is also in good agreement with a similar study by Girazian and Withers (2013) on the ionosphere of Mars. We use this power law to estimate the peak electron density at the subsolar point of Titan during solar maximum conditions and find it to be about 6500cm−3, i.e., 85–160% more than has been measured during the entire Cassini mission.
Additional attenuation of natural VLF electromagnetic waves observed by the DEMETER spacecraft resulting from preseismic activity
Authors: Píša David , Němec František , Santolík Ondřej , Parrot Michel , Rycroft Michael
Published: July 2013

We use VLF electromagnetic wave data measured by the DEMETER (Detection of Electro‐Magnetic Emissions Transmitted from Earthquake Regions) satellite at an altitude of about 700 km to check for the presence of statistically significant changes of natural wave intensity (due to signals from lightning) related to preseismic activity. All the relevant data acquired by DEMETER during almost 6.5 years of the mission have been analyzed using a robust two‐step data‐processing schema. This enables us to compare data from the vicinity of about 8400 earthquakes with an unperturbed background distribution based on data collected during the whole DEMETER mission and to evaluate the statistical significance of the observed effects. We confirm previously reported results of a small but statistically significant decrease of the wave intensity (by ∼2 dB) at frequencies of about 1.7 kHz. The effect is observed for a few hours before the times of the main shocks; it occurs during the night. The effect is stronger between March and August, at higher latitudes and for the positions of hypocenters below the sea. We suggest an explanation based on changed properties of the lower boundary of the ionosphere, which leads to a decrease of the intensity of lightning‐generated whistlers observed at the spacecraft altitude. This effect might result from a lowering of the ionosphere associated with an increase in the electrical conductivity of the lower troposphere due to an additional ionization of air molecules at the Earth's surface prior to earthquakes.
Establishment of a fast and high yield method for routine production of [131I]MIBG and investigation of its radiochemical stability for diagnosis and treatment uses
Authors: Davarpanah M. R. , Attar Nosrati S. , Khoshhosn H. A. , Fazlali M. , Kazemi Boudani M.
Published: July 2013

In this work, exchange radioiodination of metaiodobenzylguanidine (MIBG) was carried out at optimum conditions that facilitates the production of [131I]MIBG both quickly and efficiently. The radiochemical purity and yield of the labeled product are typically as high as 99% and 90% for diagnostic dose and 95% and 80% for therapeutic dose, respectively. Stability studies show that labeled material at the room temperature met the demand of the clinical application. This labeling procedure will be used in the routine production process of [131I]MIBG for diagnosis and treatment uses.
Survey of the methods and reporting practices in published meta‐analyses of test performance: 1987 to 2009
Authors: Dahabreh Issa J. , Chung Mei , Kitsios Georgios D. , Terasawa Teruhiko , Raman Gowri , Tatsioni Athina , Tobar Annette , Lau Joseph , Trikalinos Thomas A. , Schmid Christopher H.
Published: July 2013

We performed a survey of meta‐analyses of test performance to describe the evolution in their methods and reporting. Studies were identified through MEDLINE (1966–2009), reference lists, and relevant reviews. We extracted information on clinical topics, literature review methods, quality assessment, and statistical analyses. We reviewed 760 publications reporting meta‐analyses of test performance, published between 1987 and 2009. Eligible reviews included a median of 18 primary studies that were used in quantitative analyses. Most common clinical areas were cardiovascular disease (21%) and oncology (25%); most common test categories were imaging (44%) and biomarker tests (28%). Assessment of verification and spectrum bias, blinding, prospective study design, and consecutive patient recruitment became more common over time (p < 0.001 comparing reviews published through 2004 vs 2005 onwards). These changes coincided with the increasing use of checklists to guide assessment of methodological quality. Heterogeneity tests were used in 58% of meta‐analyses; subgroup or regression analyses were used in 57%. Random effects models were employed in 57% of meta‐analyses (38% through 2004 vs 72% 2004–onwards; p < 0.001). Use of bivariate models of sensitivity and specificity increased in recent years (21% in 2008–2009 vs 7% in earlier years; p < 0.001). Methods employed in meta‐analyses of test performance have improved with the introduction of quality assessment checklists and the development of more sophisticated statistical methods. Copyright © 2013 John Wiley & Sons, Ltd.
Application of ionic‐liquid‐supported magnetic dispersive solid‐phase microextraction for the determination of acaricides in fruit juice samples
Authors: Zhang Jiaheng , Li Min , Li Yubo , Li Zongyang , Wang Fenfen , Li Qiu , Zhou Wenfeng , Lu Runhua , Gao Haixiang
Published: July 2013

In this study, ionic liquid (IL) supported magnetic dispersive solid‐phase microextraction was developed and a systematic investigation was conducted on imidazolium ILs for their extraction performance. This nano‐based pretreatment procedure was then applied for the determination of acaricides in fruit juice samples for the first time. A feature of this technique is that the commonly laborious chemical modification of magnetic nanoparticles (MNPs) was skillfully circumvented. Because of the combination of ILs, dispersive liquid–liquid microextraction, and dispersive MNP solid‐phase microextraction, the extraction efficiency can be significantly improved using commercial MNPs. Parameters of the extraction method were investigated by one‐factor‐at‐a‐time approach. The optimal experimental conditions were as follows: emulsification for 2 min by sonication with the addition of 50 μL [C6MIM][NTf2] in the dispersive liquid–liquid microextraction step and vortexing for 90 s after adding 40 mg spherical barium ferrite nanoparticles (20 nm). The desorption time was 2 min. Good linearity (0.5–500 ng/mL) and detection limits within the range of 0.05–0.53 ng/mL were achieved. The application of the proposed method was demonstrated by the analysis of real fruit juice samples, in which recoveries between 85.1 and 99.6% were obtained.
On‐line two‐dimensional LC: A rapid and efficient method for the determination of enantiomeric excess in reaction mixtures
Authors: Liu Qi , Jiang Xinyu , Zheng Haixing , Su Wen , Chen Xiaoqing , Yang Hua
Published: July 2013

A novel LC‐based method for the determination of enantiomeric excess (ee) in a sample mixture has been developed by employing on‐line 2D LC. The orthogonal separation system is composed of an NH2 column as the first dimension to elute the target chiral compound from the crude mixture and a chiral column as the second dimension to determine the ee of the target chiral product. A series of crude mixtures from asymmetric reactions have been directly analyzed without prepurification. Good reproducibility (intra‐ and interday precisions were all under 1.33%) and good accuracy (deviations from ee values determined by 1D HPLC were all <1.03%) have been obtained. Compared with the traditional method for the determination of ee, on‐line 2D HPLC can be used in real time and holds great potential in the time‐saving determination of ee in asymmetric synthesis.
Determination of neurotransmitter amino acids in mouse central nervous system by CE–LIF
Authors: Xiong Xu‐Jie , Guo Xiao‐Feng , Ge Xu‐Xia , Wang Hong , Zhang Hua‐Shan
Published: July 2013

An MEKC method with LIF detection has been developed for the determination of seven neurotransmitter amino acids (NAAs) using 1,3,5,7‐tetramethyl‐8‐(N‐hydroxysuccinimidyl butyric ester)difluoroboradiaza‐S‐indacene as the labeling reagent. After derivatization at room temperature for 30 min, the seven target NAAs including glycine, alanine, γ‐aminobutyric acid, taurine, glutamine, glutamic acid, and aspartic acid were separated in running buffer, which consisted of 70 mM pH 4.00 H3PO4/Na3PO4 buffer, 5.5 mM cetyltrimethyl ammonium bromide and 20% v/v acetonitrile within 17 min. The LODs were 2 ∼ 14 × 10−10 M without interference from other coexisting amino acids. The proposed method has been applied to the analysis of NAAs in the central nervous systems of healthy mice and those with Alzheimer's disease with recoveries of 92–104%.
CAD Model to Predict the Effect of Radome on the Characteristics of Rectangular Patch Antenna
Authors: Biswas Mantosh , Banik Sourav , Biswas Mahitosh , Sukla Archana
Published: July 2013

A simple CAD model based on cavity model analysis is proposed to compute accurately the resonant frequency, input impedance, and gain of radome loaded rectangular patch antenna. The computed values using present model for wide range of radome parameters are compared with different theoretical and experimental values available in open literature. To validate the present model, we have performed several sets of experiments. The present model shows very close agreements with the experiments compared to the other models. We have also used electromagnetic software (HFSS) to generate simulated data. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2460–2468, 2013
Low Cost E/O and O/E Modules for Radio Over Fibre Link
Authors: Łysiuk Anna , Godziszewski Konrad , Yashchyshyn Yevhen
Published: July 2013

In this article low cost and low complexity E/O and O/E modules for radio over fibre link have been presented. The modules are built based on pigtail coaxial laser diode and photodiode available on the market. In the designs special attention has been focused on achieving flat transmission characteristics in the frequency range of 1‐3 GHz. The modules have been equipped with signalization of the proper supply and generation of optical carrier. The devices have been dedicated to transmission of modulated RF signals through optical fibre in radio over fibre link. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2423–2425, 2013
Small Planar Dual‐Band Microstrip‐Fed Monopole Antenna for Wireless Local Area Network Applications Using Slotted Conductor‐Backed Plane
Authors: Moosazadeh Mahdi , Esmati Zahra
Published: July 2013

This article presented a dual‐band monopole antenna fed by a 50‐Q microstrip line for wireless local area network applications. The antenna consists of a square patch as radiator and slotted conductor‐backed plane which can generate dual‐band operations. The slotted conductor‐backed plane produces two resonant bands at about 2.4 GHz for the 802.11b standard and 5 GHz for the upper band of the 802.11a. By adjusting the positions and the lengths of these structures of slots on the conductor‐backed plane, two different current paths can be obtained at different frequency bands. The designed antenna has a small overall size of 15 × 15 mm2, and operates over the frequency ranges, 2.4–2.5 GHz and 4.2–7.5 GHz suitable, which can cover the frequency bands from 2.4 to 2.484 GHz, for the 802.11b standard and from 5.15 to 5.35 GHz (the lower band) and from 5.725 to 5.825 GHz (the higher band) for the 802.11a standard. Simulation and measurement results of the proposed antenna show good agreements. Experimental results show that the proposed dual‐band antenna has good characteristics in terms of radiation pattern and gains. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2380–2383, 2013
Efficient Closed‐Form Green's Functions for Layered Stripline Structures
Authors: Dingand Jun , Dvorak Steven L.
Published: July 2013

In this article, simple and efficient closed‐form Green's function representations for various inhomogeneously‐filled (layered) stripline structures are derived in terms of cylindrical and spherical waves for a horizontal electric dipole source. The method is based on a two‐level approximation of the spectral‐domain Green's function. After using a fast pole‐location method to extract the surface‐wave modes that are guided by the dielectric slabs and the parallel‐plate modes that are trapped by the two ground planes, we first use a method that is similar to the first step in the traditional two‐level discrete complex image method (DCIM). This step provides a good approximation to the spectral‐domain Green's function for large values of the spectral variable
, thus accounting for the fields at near and intermediate distances from the source. The remainder (smaller values of
) of the spectral‐domain Green's function is approximated using a few poles and residues by using the total least squares algorithm, which requires much less computational resources as compared to the vector fitting method or DCIM. This portion of the Green's function accounts well for the fields that are further away from the source. Our proposed method provides an efficient and accurate means for representing Green's functions in layered stripline structures both near and far from the source. The results are verified by comparing with those obtained using the traditional two‐level DCIM as well as direct numerical integration of the spectral‐domain Green's function. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2261–2265, 2013
Low‐cost OFDM Direct Detection Passive Optical Network
Authors: Stepniak G.
Published: July 2013

In this article, operation of a low‐cost orthogonal frequency division multiplexing–based passive optical network is presented. At the optical network units, the received signal is downconverted and filtered in analog domain, which enables use of analog to digital converters of low sampling rates. The conception is verified experimentally. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2504–2507, 2013
Electrically Small Broadband VHF/UHF Planar Antenna Matched Using a Non‐Foster Circuit
Authors: Alam Md. Nazmul , Dougal Roger A. , Ali Mohammod
Published: July 2013

A broadband non‐Foster matched Planar Inverted‐F Antenna is proposed for 100–500 MHz VHF/UHF handheld terminal applications. The proposed design shows that in the lower frequencies antenna gain improvement of as much as 25 dB can be obtained with the help of the broadband matching circuit for a small antenna on a 0.05 wavelength ground plane at the lowest frequency. The issues of RF power versus matching and circuit stability are pointed out. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2494–2497, 2013
Study of Link Gain and Locking Range in Hybrid Mode‐Locked Laser‐Based MillimeteR‐Wave Radio‐Over‐Fiber System
Authors: Khawaja Bilal A. , Cryan Martin J.
Published: July 2013

An investigation of hybrid mode‐locked lasers is performed to better understand their link gain and locking range behavior under external RF injection for their use in millimeter wave radio‐over‐fiber systems. The dependence of 40‐GHz link gain on different parameters is initially identified and then the three main parameters of gain and saturable absorber section biases and external RF injection signal power are studied in detail. It is found that higher injection power leads to lower link gain ranging from −19dB to −22dB, whereas lower injection power gives higher link gain ranging from −10dB to −19.9dB. This article also reports a hybrid mode‐locking range of 90.97 MHz which is the widest reported so far for the technique used here. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2450–2454, 2013
A Solar‐Powered 2.4‐GHz LNA RFIC
Authors: Wu Jian‐Ming , Lin Yan‐Tsang
Published: July 2013

A 2.4‐GHz low‐noise amplifier (LNA) radio frequency integrated circuit is designed and implemented using the 18‐μm CMOS standard process for ZigBee applications. A solar panel with a regulator circuit directly converts solar power to the electrical power of the LNA. The forward body bias method is applied to reduce the power consumed by the LNA, as required to provide green energy. Measurements of the solar‐powered 2.4‐GHz LNA are made, revealing that the noise figure is 2.91 dB, the gain is 10.89 dB, and the input‐referred third‐order intercept point is 0 dBm. A voltage of 0.6 V is supplied to the LNA and the power consumption is then 1.08 mW. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2377–2380, 2013
Wideband Square Loop Antenna with Parasitic Loop Component
Authors: Lee Hyeonjin , Kim Tae‐Hong
Published: July 2013

In this article, we designed the broadband square loop antenna with a parasitic loop. To increase bandwidth of the single square loop antenna, we desinged the antenna with the parasitic loop at outside of the square loop. The feeding method of the proposed antenna is fed by a coplanar waveguide structure. We analyzed and designed the antenna by using Ansoft co.' HFSS. The bandwidth of the proposed antenna with the parasitic loop was increased above 2.5 times compared with single square loop antenna. The proposed antenna has an impedance bandwidth of 2.52 GHz under the condition below voltage standing wave ratio two and a maximum gain of 8.7 dBi at the operating frequency of 6.4 GHz. The designed antenna could be used to support WLAN communications and ITS applications bands. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2302–2304, 2013
V‐Band Push‐Push VCO using Slow‐Wave CPW Resonators for Low Phase Noise Reduction
Authors: Ke Po‐Yu , Chiu Hsien‐Chin , Huang Fan‐Hsiu , Kao Hsuan‐Ling , Chien Feng‐Tsun
Published: July 2013

This article presents a design for two fully integrated millimeter‐wave V‐band push–push voltage‐controlled oscillators (VCOs) implemented in a 150‐nm pHEMT process is presented. Both use slow‐wave coplanar waveguide (CPW) structure transmission line resonators, instead of a lumped LC tank, to provide an extended output frequency range and relatively low phase noise (PN). A LC tank with and without slow‐wave features is used in the two VCO circuits. The measured results for manufactured chips are compared. The VCO with the slow‐wave feature demonstrates a lower PN of −104.5 dBc/Hz at a 1‐MHz offset frequency. A comparison of the designs with and without a slow‐wave VCO shows that the VCO design with slow wave demonstrates lower average PN of approximately 8 dBc at an offset frequency of 1 MHz. Varactor adjustment of the oscillation frequencies for the two VCOs gives 53.2 to 57.1 GHz for the VCO without slow wave and 53.8 to 55.4 GHz for the VCO with slow wave. The two VCOs are developed for use in licensed V‐band transceiver systems. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2373–2377, 2013
Miniaturized Microstrip Ring Hybrid with Defected Microstrip Structure
Authors: Salari Mohammad Ali , Manoochehri Omid , Abbasiniazare Seyyedpayam
Published: July 2013

A method for miniaturization of microstrip rat‐race hybrid with the aid of “defected microstrip structure (DMS)” is proposed. Each transmission line section is loaded with cascaded DMS sections. This results in slow‐wave characteristics which in turn increases the electrical length of the line. In the frequency range below the bandgap, the phase of S21 is negative and DMS behaves as a slow wave device; allowing a miniaturized structure. A reduction of 50% in the occupied area of the circuit and no bandwidth reduction is achieved using this technique. The miniaturized rat‐race operates at 3.4 GHz and can be used in LTE systems. The circuits are fabricated and the measured and simulated results are in excellent agreement. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2245–2248, 2013
Loop‐Tree Free Augmented Equivalence Principle Algorithm for Low‐Frequency Problems
Authors: Ma Zu‐Hui , Jiang Li Jun , Chew Weng Cho
Published: July 2013

In this article, we describe a newly developed integral equation domain decomposition method for solving complex low frequency electromagnetic problems. This method is based on low frequency augmented equivalence principle algorithm (EPA) with the augmented electric field integral equation (A‐EFIE). The A‐EFIE provides a stable solution in the low‐frequency regime as it includes both charge and current as unknowns to avoid the imbalance between the vector potential and the scalar potential. Based on similar idea, the augmented EPA can suppress the projection error resulting from low‐frequency problems of the normal EPA. Combining these two methods, the proposed algorithm can be used in domain decomposition problems and is numerically stable at low frequencies. Several numerical examples are provided to verify its validity. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2475–2479, 2013