bluuebunny/crossref_metadata_2025 huggingface dataset:
Inter‐Rater Reliability and Measurement Error of Sonographic Muscle Architecture Assessments
Authors: König Niklas , Cassel Michael , Intziegianni Konstantina , Mayer Frank
Published: April 2014

Objectives

Sonography of muscle architecture provides physicians and researchers with information about muscle function and muscle‐related disorders. Inter‐rater reliability is a crucial parameter in daily clinical routines. The aim of this study was to assess the inter‐rater reliability of sonographic muscle architecture assessments and quantification of errors that arise from inconsistent probe positioning and image interpretation.

Methods

The medial gastrocnemius muscle of 15 healthy participants was measured with sagittal B‐mode ultrasound scans. The muscle thickness, fascicle length, superior pennation angle, and inferior pennation angle were assessed. The participants were examined by 2 investigators. A custom‐made foam cast was used for standardized positioning of the probe. To analyze inter‐rater reliability, the examinations of both raters were compared. The impact of probe positioning was assessed by comparison of foam cast and freehand scans. Error arising from picture interpretation was assessed by comparing the investigators' analyses of foam cast scans independently. Reliability was expressed as the intraclass correlation coefficient (ICC), inter‐rater variability (IRV), Bland‐Altman analysis (bias ± limits of agreement [LoA]), and standard error of measurement (SEM).

Results

Inter‐rater reliability was good overall (ICC, 0.77–0.90; IRV, 9.0%–13.4%; bias ± LoA, 0.2 ± 0.2–1.7 ± 3.0). Superior and inferior pennation angles showed high systematic bias and LoA in all setups, ranging from 2.0° ± 2.2° to 3.4° ± 4.1°. The highest IRV was found for muscle thickness (13.4%). When the probe position was standardized, the SEM for muscle thickness decreased from 0.1 to 0.05 cm.

Conclusions

Sonographic examination of muscle architecture of the medial gastrocnemius has good to high reliability. In contrast to pennation angle measurements, length measurements can be improved by standardization of the probe position.
Preoperative Assessment of Extrathyroidal Extension of Papillary Thyroid Carcinoma
Authors: Gweon Hye Mi , Son Eun Ju , Youk Ji Hyun , Kim Jeong-Ah , Park Cheong Soo
Published: April 2014

Objectives

The purpose of this study was to evaluate the diagnostic performance and interobserver agreement of 2‐dimensional (2D) and 3‐dimensional (3D) sonography for evaluating extrathyroidal extension of papillary thyroid carcinoma.

Methods

A total of 79 papillary thyroid carcinomas in 79 patients who underwent both 2D and 3D sonography for preoperative staging of papillary thyroid carcinoma were included. When the lesion was abutting on the thyroid capsule on 2D sonography, 3D sonography was performed. Three radiologists reviewed 3 data sets: 2D sonography, 3D sonography, and a combined set of both for tumor staging. The diagnostic performance, including sensitivity, specificity, positive predictive value, negative predictive value, and accuracy, for extrathyroidal extension was analyzed. Interobserver agreement of the 3 radiologists was assessed with κ values.

Results

The overall accuracy rates for 2D sonography, 3D sonography, and the combined set in predicting extrathyroidal extension were 60.8%, 66.2%, and 67.9%, respectively. The accuracy of the combined set was significantly higher than that of 2D sonography (P = .016). The interobserver agreement of the 3 reviewers was fair (κ = 0.33) for 2D sonography and moderate for 3D sonography (κ = 0.46) and the combined set (κ = 0.49).

Conclusions

Adding 3D sonography to 2D sonography could improve the accuracy and interobserver agreement for predicting extrathyroidal extension of papillary thyroid carcinoma.
Meaning of Free Intraperitoneal Fluid in Small‐Bowel Obstruction
Authors: Iacobellis Francesca , Berritto Daniela , Belfiore Maria Paola , Di Lanno Imma , Maiorino Manuela , Saba Luca , Grassi Roberto
Published: April 2014

Objectives

The aim of this study was to detect the onset, evolution, and meaning of extraluminal free fluid in a rat model of small‐bowel obstruction using high‐frequency microsonography.

Methods

Small‐bowel obstruction was surgically created in 8 rats divided into 2 groups of 4 rats each. All rats were examined by high‐frequency microsonography to monitor the evolution of small‐bowel obstruction and the abdominal sonographic findings. In group 2 rats, the obstruction was resolved 2 hours after surgery.

Results

In all rats, free peritoneal fluid was detected just near the obstructed loop after 1 hour and in the hepatorenal recess after 2 hours. These features progressively increased in the following hours in group 1 rats. In group 2, the amount of free fluid decreased shortly after removing the obstruction.

Conclusions

Free fluid is an early finding in small‐bowel obstruction, and the increase or decrease of its amount is correlated with the worsening or resolution of the obstruction.
Sonographic Findings of Tuberculous Vasitis
Authors: Yang Dal Mo , Kim Hyun Cheol , Kim Sang Won , Lee Hyung Lae , Min Gyeong Eun , Lim Sung Jig
Published: April 2014

The purpose of this series was to describe the sonographic findings of tuberculous vasitis. We conducted a retrospective analysis of 3 cases of tuberculous vasitis. The following grayscale and color Doppler sonographic features were analyzed: location, echogenicity of the lesion, epididymal or testicular involvement, presence of hydrocele, and blood flow within the lesion. All 3 patients had focal (n = 2) or multifocal (n = 1) involvement of the scrotal segment of the vas deferens. The sonographic findings for tuberculous vasitis were heterogeneously hypoechoic in all of the cases. On color Doppler sonography, no blood flow was identified within the lesions of the vas deferens. All 3 patients had tuberculous epididymitis in addition to tuberculous vasitis. Tuberculous vasitis presents with infection along with tuberculous epididymitis, and it appears as a heterogeneously hypoechoic lesion in the scrotal segment of the vas deferens adjacent to the epididymal tail.
Using XHMM Software to Detect Copy Number Variation in Whole‐Exome Sequencing Data
Authors: Fromer Menachem , Purcell Shaun M.
Published: April 2014

Copy number variation (CNV) has emerged as an important genetic component in human diseases, which are increasingly being studied for large numbers of samples by sequencing the coding regions of the genome, i.e., exome sequencing. Nonetheless, detecting this variation from such targeted sequencing data is a difficult task, involving sorting out signal from noise, for which we have recently developed a set of statistical and computational tools called XHMM. In this unit, we give detailed instructions on how to run XHMM and how to use the resulting CNV calls in biological analyses. Curr. Protoc. Hum. Genet. 81:7.23.1‐7.23.21. © 2014 by John Wiley & Sons, Inc.
Stability and localization of rapid shear in fluid‐saturated fault gouge: 1. Linearized stability analysis
Authors: Rice James R. , Rudnicki John W. , Platt John D.
Published: April 2014

Field observations of major earthquake fault zones show that shear deformation is often confined to principal slipping zones that may be of order 1–100 μm wide, located within a broader gouge layer of order 10–100 mm wide. This paper examines the possibility that the extreme strain localization observed may be due to the coupling of shear heating, thermal pressurization, and diffusion. In the absence of a stabilizing mechanism shear deformation in a continuum analysis will collapse to an infinitesimally thin zone. Two possible stabilizing mechanisms, studied in this paper, are rate‐strengthening friction and dilatancy. For rate‐strengthening friction alone, a linear stability analysis shows that uniform shear of a gouge layer is unstable for perturbations exceeding a critical wavelength. Using this critical wavelength we predict a width for the localized zone as a function of the gouge properties. Taking representative parameters for fault gouge at typical centroidal depths of crustal seismogenic zones, we predict localized zones of order 5–40 μm wide, roughly consistent with field and experimental observations. For dilatancy alone, linearized strain rate perturbations with a sufficiently large wavelength will undergo transient exponential growth before decaying back to uniform shear. The total perturbation strain accumulated during this transient strain rate localization is shown to be largely controlled by a single dimensionless parameter E, which is a measure of the dilatancy of the gouge material due to an increase in strain rate.
Risk assessment of tropical storm surges for coastal regions of China
Authors: Gao Y. , Wang H. , Liu G. M. , Sun X. Y. , Fei X. Y. , Wang P. T. , Lv T. T. , Xue Z. S. , He Y. W.
Published: April 2014

Storm surges are responsible for much of the damage and loss of life associated with landfalling tropical cyclones (TCs). Thus, understanding the characteristics of risk associated with TC storm surges for the coastal regions of China is of great interest. Based on a comprehensive assessment of hazard indices for TC storm surges and vulnerability indices for coastal counties, we obtained a risk assessment for coastal regions of China as a county‐level unit. The hazard index was calculated using a model based on the parameters of a TC landfall frequency index (f) and maximum storm surge elevation (MSSE). The MSSE was calculated from the TC maximum sustained wind and tide gauge records using a regression function. Vulnerability indices were obtained from indices on socioeconomics, land use, the ecological environment, and resilience. From this study, it can be concluded that the hazard level of TC storm surges increases from north to south along the Chinese coast, the vulnerabilities have significant spatial heterogeneity, and coastal regions of China can be divided into four zones of risk level. The results of this study can provide scientific support for marine disaster mitigation and decision making. Additionally, the risk assessment methodology used here for storm surges could be extended and applied to other coastal areas.
Evaluating the impact of aerosol particles above cloud on cloud optical depth retrievals from MODIS
Authors: Alfaro‐Contreras Ricardo , Zhang Jianglong , Campbell James R. , Holz Robert E. , Reid Jeffrey S.
Published: April 2014

Using two different operational Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) cloud optical depth (COD) retrievals (0.86 versus 1.6 µm), we evaluate the impact of above‐cloud smoke aerosol particles on near‐IR (0.86 µm) COD retrievals. Aerosol Index (AI) from the collocated Ozone Monitoring Instrument (OMI) are used to identify above‐cloud aerosol particle loading over the southern Atlantic Ocean, including both smoke and dust from the African subcontinent. Collocated Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation data constrain cloud phase and provide contextual above‐cloud aerosol optical depth. The frequency of occurrence of above‐cloud aerosol events is depicted on a global scale for the spring and summer seasons from OMI and Cloud Aerosol Lidar with Orthogonal Polarization. Seasonal frequencies for smoke‐over‐cloud off the southwestern Africa coastline reach 20–50% in boreal summer. We find a corresponding low COD bias of 10–20% for standard MODIS COD retrievals when averaged OMI AI are larger than 1. No such bias is found over the Saharan dust outflow region off northern Africa, since both MODIS 0.86 and 1.6 µm channels are vulnerable to radiance attenuation due to dust particles. A similar result is found for a smaller domain, in the Gulf of Tonkin region, from smoke advection over marine stratocumulus clouds and outflow into the northern South China Sea in spring. This study shows the necessity of accounting for the above‐cloud aerosol events for future studies using standard MODIS cloud products in biomass burning outflow regions, through the use of collocated OMI AI and supplementary MODIS 1.6 µm COD products.
Decadal change of South China Sea tropical cyclone activity in mid‐1990s and its possible linkage with intraseasonal variability
Authors: Ha Yao , Zhong Zhong , Sun Yuan , Lu Wei
Published: April 2014

This study focuses on the decadal variability of tropical cyclone (TC) activity over the South China Sea (SCS) since the 1970s and its possible cause behind. It is found that TC activity over the SCS experiences a significant decadal change around the mid‐1990s. Compared to the period from the 1970s to the early 1990s, the number of TCs formed in the SCS remarkably increases from the mid‐1990s through the 2000s. In particular, this change of TC genesis is closely related to a decadal shift in atmospheric intraseasonal variability (ISV) that occurred in 1994. The ISV on the 30–60 days time scale over the SCS has been increasing since the mid‐1990s, and the increased TC frequency after 1994 is attributed primarily to the active convection induced by the enhancement of the SCS ISV. In addition, the TC activities before the mid‐1990s are mostly confined within the SCS basin. However, more TCs form over the SCS and move northeastward since the mid‐1990s and finally enter the East China Sea and the Philippine Sea. Anomalies of westerly over the northern SCS after 1994 are responsible for the northeastward moving of TCs.
Evaluation of the GLD360 performance characteristics using rocket‐and‐wire triggered lightning data
Authors: Mallick S. , Rakov V. A. , Ngin T. , Gamerota W. R. , Pilkey J. T. , Hill J. D. , Uman M. A. , Jordan D. M. , Nag A. , Said R. K.
Published: April 2014

We estimated the performance characteristics of the Global Lightning Dataset (GLD360) using rocket‐and‐wire triggered lightning data acquired at Camp Blanding, Florida, in 2011–2013. The data set consisted of 201 return strokes and 84 kiloampere‐scale (≥1 kA) superimposed pulses (initial continuous current pulses and M components) in 43 flashes. All the events transported negative charge to ground. The GLD360 detected 75 strokes and 4 superimposed pulses in 29 flashes. The resultant detection efficiencies were 67% for flashes, 37% for strokes, and 4.8% for superimposed pulses. Out of 75 detected strokes, one (1.3%) was reported with incorrect polarity. The median location error was 2.0 km, and the median absolute current estimation error was 27%. This is the first comprehensive evaluation of GLD360 performance characteristics relative to absolute ground truth, with all previous evaluations being at least in part relative to other locating systems. The results presented in this work may be applicable to regions in and around Florida.
Alfvén wave boundary condition for responsive magnetosphere‐ionosphere coupling
Authors: Wright Andrew N. , Russell Alexander J. B.
Published: April 2014

The solution of electric fields and currents in a height‐resolved ionosphere is traditionally solved as an elliptic equation with Dirichlet or Neumann boundary condition in which the magnetosphere is represented as an unresponsive (prescribed) voltage generator or current source. In this paper we derive an alternative boundary condition based upon Alfvén waves in which only the Alfvén wave from the magnetosphere that is incident upon the ionosphere (Exi) is prescribed. For a uniform magnetosphere the new boundary condition reduces to
urn:x-wiley:21699380:media:jgra51002:jgra51002-math-0001and is evaluated at the magnetosphere‐ionosphere interface. The resulting solution is interpreted as a responsive magnetosphere and establishes a key stage in the full self‐consistent and nonlinear coupling of the magnetosphere and ionosphere.
A numerical study of chorus generation and the related variation of wave intensity using the DAWN code
Authors: Tao X.
Published: April 2014

Chorus waves play an important role in energetic electron dynamics in the inner magnetosphere. In this work, we present a new hybrid code, DAWN, to simulate the generation of chorus waves. The DAWN code is unique in that it models cold electrons using linearized fluid equations and hot electrons using particle‐in‐cell techniques. The simplified fluid equations can be solved with robust and simple algorithms. We demonstrate that discrete chorus elements can be generated using the code. Waveforms of the generated element show amplitude modulation or “subpackets,” and the frequency sweep rate of the generated element is found to be consistent with that of observed chorus waves. Using the DAWN code, we then investigate the variation of wave intensity () with respect to linear growth rates on the equatorial plane. Previous observations showed that the change in linear growth rates of whistler waves modulated by external processes such as density modulations is usually small (), while the variation of the wave intensity is large (). Using a chosen set of background plasma parameters, we demonstrate that a small change () in linear growth rates can lead to significant variation () of wave intensity only in the transition from the broadband whistler wave generation regime to the chorus wave generation regime. Our results demonstrate the importance of including nonlinear dynamics of chorus generation in understanding the whistler wave intensity modulation process in the inner magnetosphere.
Continental heat anomalies and the extreme melting of the Greenland ice surface in 2012 and 1889
Authors: Neff William , Compo Gilbert P. , Martin Ralph F. , Shupe Matthew D.
Published: April 2014

Recent decades have seen increased melting of the Greenland ice sheet. On 11 July 2012, nearly the entire surface of the ice sheet melted; such rare events last occurred in 1889 and, prior to that, during the Medieval Climate Anomaly. Studies of the 2012 event associated the presence of a thin, warm elevated liquid cloud layer with surface temperatures rising above the melting point at Summit Station, some 3212 m above sea level. Here we explore other potential factors in July 2012 associated with this unusual melting. These include (1) warm air originating from a record North American heat wave, (2) transitions in the Arctic Oscillation, (3) transport of water vapor via an Atmospheric River over the Atlantic to Greenland, and (4) the presence of warm ocean waters south of Greenland. For the 1889 episode, the Twentieth Century Reanalysis and historical records showed similar factors at work. However, markers of biomass burning were evident in ice cores from 1889 which may reflect another possible factor in these rare events. We suggest that extreme Greenland summer melt episodes, such as those recorded recently and in the late Holocene, could have involved a similar combination of slow climate processes, including prolonged North American droughts/heat waves and North Atlantic warm oceanic temperature anomalies, together with fast processes, such as excursions of the Arctic Oscillation, and transport of warm, humid air in Atmospheric Rivers to Greenland. It is the fast processes that underlie the rarity of such events and influence their predictability.
Impact of Substrate and Processing on Confinement of Nafion Thin Films
Authors: Kusoglu Ahmet , Kushner Douglas , Paul Devproshad K. , Karan Kunal , Hickner Michael A. , Weber Adam Z.
Published: April 2014

Thin films of ion‐conducting polymers are an important area of study due to their function in many electrochemical devices and as analogues for interfacial phenomena that occur in bulk films. In this paper, the properties of Nafion, a prototypical ionomer, are investigated as thin films (4 to 300 nm) on carbon, gold, and platinum substrates that are fabricated using different casting methods and thermal histories. Specifically, water uptake, swelling, and morphology are investigated by quartz‐crystal microbalance, ellipsometry, and grazing‐incidence X‐ray scattering to develop structure/property/processing relationships. For all substrates, as the films' thickness decreased, there is an initial decrease in swelling followed by a subsequent increase for film thicknesses below ≈20 nm due to a disordering of the film hydrophilic/hydrophobic structure. Decreased swelling and less structural order is observed on gold for spin‐cast films compared to self‐assembled films; the opposite effect is observed for films on carbon. The presented systematic data set and analyses represent a thorough study of the behavior of Nafion thin films on model substrates of interest in metal catalyst/carbon electrodes, and these insights help to elucidate the underlying polymer physics and confinement effects in these and related systems.
Gate Capacitance‐Dependent Field‐Effect Mobility in Solution‐Processed Oxide Semiconductor Thin‐Film Transistors
Authors: Lee Eungkyu , Ko Jieun , Lim Keon‐Hee , Kim Kyongjun , Park Si Yun , Myoung Jae M. , Kim Youn Sang
Published: April 2014

Solution‐processed oxide semiconductors (OSs) used as channel layer have been presented as a solution to the demand for flexible, cheap, and transparent thin‐film transistors (TFTs). In order to produce high‐performance and long‐sustainable portable devices with the solution‐processed OS TFTs, the low‐operational voltage driving current is a key issue. Experimentally, increasing the gate‐insulator capacitances by high‐k dielectrics in the OS TFTs has significantly improved the field‐effect mobility of the OS TFTs. But, methodical examinations of how the field‐effect mobility depends on gate capacitance have not been presented yet. Here, a systematic analysis of the field‐effect mobility on the gate capacitances in the solution‐processed OS TFTs is presented, where the multiple‐trapping‐and‐release and hopping percolation mechanism are used to describe the electrical conductivity of the nanocrystalline and amorphous OSs, respectively. An intuitive single‐piece expression showing how the field‐effect mobility depends on gate capacitance is developed based on the aforementioned mechanisms. The field‐effect mobility, depending on the gate capacitances, of the fabricated ZnO and ZnSnO TFTs clearly follows the theoretical prediction. In addition, the way in which the gate insulator properties (e.g., gate capacitance or dielectric constant) affect the field‐effect mobility maximum in the nanocrystalline ZnO and amorphous ZnSnO TFTs are investigated.
Mild nasal clefting may be predictive for ALX4 heterozygotes
Authors: Altunoglu Umut , Satkın Bilge , Uyguner Zehra Oya , Kayserili Hülya
Published: April 2014

Heterozygous loss‐of‐function mutations in ALX4 are responsible for enlarged parietal foramina, whereas patients with biallelic ALX4 mutations display a phenotypic spectrum of clinical findings, from mild to severe alopecia, cranium bifidum, hypertelorism, microphthalmia, with alar clefting being the pivotal sign in all affecteds. We report on four affected individuals in a three‐generation family, displaying a phenotypic spectrum ranging from mild nasal clefting and broad columella to subtle changes in nasal configuration in addition to parietal foramina, caused by a novel ALX4 mutation (c.646C>G, p.Arg216Gly). This is the second report of a family showing vertical transmission of a dominant ALX4 mutation with facial involvement in addition to parietal foramina, mimicking mild recessive ALX4 phenotype. We discuss possible pathological mechanisms that may have lead to phenotypic variation in the family and challenges in genetic counseling. © 2014 Wiley Periodicals, Inc.
Palladium‐Catalyzed Heck‐Type Cross‐Couplings of Unactivated Alkyl Iodides
Authors: McMahon Caitlin M. , Alexanian Erik J.
Published: April 2014

A palladium‐catalyzed, intermolecular Heck‐type coupling of alkyl iodides and alkenes is described. This process is successful with a variety of primary and secondary unactivated alkyl iodides as reaction partners, including those with hydrogen atoms in the β position. The mild catalytic conditions enable intermolecular CC bond formations with a diverse set of alkyl iodides and alkenes, including substrates containing base‐ or nucleophile‐sensitive functionality.
Enhanced Anticancer Efficacy by ATP‐Mediated Liposomal Drug Delivery
Authors: Mo Ran , Jiang Tianyue , Gu Zhen
Published: April 2014

A liposome‐based co‐delivery system composed of a fusogenic liposome encapsulating ATP‐responsive elements with chemotherapeutics and a liposome containing ATP was developed for ATP‐mediated drug release triggered by liposomal fusion. The fusogenic liposome had a protein–DNA complex core containing an ATP‐responsive DNA scaffold with doxorubicin (DOX) and could release DOX through a conformational change from the duplex to the aptamer/ATP complex in the presence of ATP. A cell‐penetrating peptide‐modified fusogenic liposomal membrane was coated on the core, which had an acid‐triggered fusogenic potential with the ATP‐loaded liposomes or endosomes/lysosomes. Directly delivering extrinsic liposomal ATP promoted the drug release from the fusogenic liposome in the acidic intracellular compartments upon a pH‐sensitive membrane fusion and anticancer efficacy was enhanced both in vitro and in vivo.
Stereospecific Formal [3+2] Dipolar Cycloaddition of Cyclopropanes with Nitrosoarenes: An Approach to Isoxazolidines
Authors: Chakrabarty Shyamal , Chatterjee Indranil , Wibbeling Birgit , Daniliuc Constantin Gabriel , Studer Armido
Published: April 2014

The MgBr2‐catalyzed formal [3+2] cycloaddition of donor–acceptor activated cyclopropanes with nitrosoarenes offers a novel approach to various structurally diverse isoxazolidines. The reactions, which are experimentally easy to conduct, occur with complete stereospecificity and perfect control of regioselectivity. Product isoxazolidines can be readily transformed into α‐amino lactones by reductive or decarboxylative NO cleavage and subsequent lactonisation, and the N‐aryl bond cleavage is also possible under oxidative conditions.
Dual‐Pore Mesoporous Carbon@Silica Composite Core–Shell Nanospheres for Multidrug Delivery
Authors: Fang Yin , Zheng Gengfeng , Yang Jianping , Tang Haosha , Zhang Yafeng , Kong Biao , Lv Yingying , Xu Congjian , Asiri Abdullah M. , Zi Jian , Zhang Fan , Zhao Dongyuan
Published: April 2014

Monodispersed mesoporous phenolic polymer nanospheres with uniform diameters were prepared and used as the core for the further growth of core–shell mesoporous nanorattles. The hierarchical mesoporous nanospheres have a uniform diameter of 200 nm and dual‐ordered mesopores of 3.1 and 5.8 nm. The hierarchical mesostructure and amphiphilicity of the hydrophobic carbon cores and hydrophilic silica shells lead to distinct benefits in multidrug combination therapy with cisplatin and paclitaxel for the treatment of human ovarian cancer, even drug‐resistant strains.
Engineering the Stereochemistry of Cephalosporin for Specific Detection of Pathogenic Carbapenemase‐Expressing Bacteria
Authors: Shi Haibin , Cheng Yunfeng , Lee Kyung Hyun , Luo Robert F. , Banaei Niaz , Rao Jianghong
Published: April 2014

Reported herein is the design of fluorogenic probes specific for carbapenem‐resistant Enterobacteriaceae (CRE) and they were designed based on stereochemically modified cephalosporin having a 6,7‐trans configuration. Through experiments using recombinant β‐lactamase enzymes and live bacterial species, these probes demonstrate the potential for use in the specific detection of carbapenemases, including metallo‐β‐lactamases in active bacterial pathogens.
In Situ Synthesis of Alkenyl Tetrazines for Highly Fluorogenic Bioorthogonal Live‐Cell Imaging Probes
Authors: Wu Haoxing , Yang Jun , Šečkutė Jolita , Devaraj Neal K.
Published: April 2014

In spite of the wide application potential of 1,2,4,5‐tetrazines, particularly in live‐cell and in vivo imaging, a major limitation has been the lack of practical synthetic methods. Here we report the in situ synthesis of (E)‐3‐substituted 6‐alkenyl‐1,2,4,5‐tetrazine derivatives through an elimination–Heck cascade reaction. By using this strategy, we provide 24 examples of π‐conjugated tetrazine derivatives that can be conveniently prepared from tetrazine building blocks and related halides. These include tetrazine analogs of biological small molecules, highly conjugated buta‐1,3‐diene‐substituted tetrazines, and a diverse array of fluorescent probes suitable for live‐cell imaging. These highly conjugated probes show very strong fluorescence turn‐on (up to 400‐fold) when reacted with dienophiles such as cyclopropenes and trans‐cyclooctenes, and we demonstrate their application for live‐cell imaging. This work provides an efficient and practical synthetic methodology for tetrazine derivatives and will facilitate the application of conjugated tetrazines, particularly as fluorogenic probes for live‐cell imaging.
Correlation of solid solubility of 1‐hydroxy‐9,10‐anthraquinone derivatives in supercritical carbon dioxide
Authors: Su Chie‐Shaan , Ciou Jhih‐Long
Published: April 2014

In this study, the solid solubilities of four 1‐hydroxy‐9,10‐anthraquinone derivatives (HAQs) in supercritical carbon dioxide (CO2) have been correlated using a two solid‐dependent parameter solution model developed from the regular solution model coupled with the Flory–Huggins equation. The correlated results show satisfactory agreement with the experimental data. In addition, with appropriate model simplification and generalization, a generalized solution model is proposed in this study to predict the solubility behavior of HAQs in supercritical CO2. By applying our generalized solution model, satisfactory calculated results are obtained and the average deviation of predicted solubilities is only about 10%. © 2014 Curtin University of Technology and John Wiley & Sons, Ltd.
Overcoming Limitations of Uncalibrated Robotics Visual Servoing by means of Sliding Mode Control and Switching Monitoring Scheme
Authors: Oliveira Tiago Roux , Leite Antonio Candea , Peixoto Alessandro Jacoud , Hsu Liu
Published: April 2014

This paper addresses the visual servoing control problem for robot manipulators without using velocity measurements, and considering a fixed but uncalibrated camera with an optical axis perpendicular to the robot workspace. A novel visual servoing strategy via sliding mode control (SMC) and a monitoring function based switching scheme is presented to deal with the uncertainties in the camera calibration parameters and to remove any restriction on the unknown camera orientation angle. The developed method provides global stability, disturbance rejection properties, and exact output tracking with better transient performance than adaptive controllers. Experimental results illustrate the robustness and practical feasibility of the proposed scheme.
Noninvasive electrical impedance sensor for in vivo tissue discrimination at radio frequencies
Authors: Dai Yu , Du Jun , Yang Qing , Zhang Jianxun
Published: April 2014

Compared to traditional open surgery, minimally invasive surgery (MIS) allows for a more rapid and less painful recovery. However, the lack of significant haptic feedback in MIS can make tissue discrimination difficult. This paper tests a noninvasive electrical impedance sensor for in vivo discrimination of tissue types in MIS. The sensor consists of two stainless steel spherical electrodes used to measure the impedance spectra over the frequency range of 200 kHz to 5 MHz. The sensor helps ensure free movement on an organ surface and prevents soft tissues from being injured during impedance measurement. Since the recorded electrical impedance is correlated with the force pressed on the electrode and the mechanical property of the tissue, the electrode‐tissue contact impedance is calculated theoretically. We show that the standard deviation of the impedance ratio at each frequency point is sufficient to distinguish different tissue types. Both in vitro experiment in a pig kidney and in vivo experiment in rabbit organs were performed to demonstrate the feasibility of the electrical impedance sensor. The experimental results indicated that the sensor, used with the proposed data‐processing method, provides accurate and reliable biological tissue discrimination. Bioelectromagnetics. Bioelectromagnetics. 35:385–395, 2014. © 2014 Wiley Periodicals, Inc.
Pulsed electromagnetic field treatment enhances healing callus biomechanical properties in an animal model of osteoporotic fracture
Authors: Androjna Caroline , Fort Brian , Zborowski Maciej , Midura Ronald J.
Published: April 2014

Delayed bone healing has been noted in osteoporosis patients and in the ovariectomized (OVX) rat model of estrogen‐depletion osteopenia. Pulsed electromagnetic field (PEMF) devices are clinically approved as an adjunct to cervical fusion surgery in patients at high risk for non‐fusion and for the treatment of fracture non‐unions. These bone growth stimulating devices also accelerate the healing of fresh fracture repair in skeletally mature normal rats but have not been tested for efficacy to accelerate and/or enhance the delayed bone repair process in OVX rats. The current study tested the hypothesis that daily PEMF treatments would improve the fracture healing response in skeletally mature OVX rats. By 6 weeks of healing, PEMF treatments resulted in improved hard callus elastic modulus across fibula fractures normalizing the healing process in OVX rats with respect to this mechanical property. Radiographic evidence showed an improved hard callus bridging across fibula fractures in OVX rats treated with PEMF as compared to sham treatments. These findings provide a scientific rationale for investigating whether PEMF might improve bone‐healing responses in at‐risk osteoporotic patients. Bioelectromagnetics. Bioelectromagnetics. 35:396–405, 2014. © 2014 Wiley Periodicals, Inc.
Validation of a sensitive LC/MS/MS method for the determination of telaprevir and its R‐isomer in human plasma
Authors: Chen Xinhui , Bushman Lane R. , McAllister Kevin J. , Anderson Peter L. , Kiser Jennifer J.
Published: April 2014

The purpose of this study was to validate a reversed‐phase high‐performance liquid chromatographic (HPLC), tandem mass spectrometry (MS/MS) assay for the determination of telaprevir and its R‐diastereomer (VRT‐127394) in acidified and nonacidified human plasma. The chromatographic baseline separation of telaprevir and telaprevir‐R was performed on a Waters XBridgeTM BEH Shield C18, 2.1 × 75 mm column with a 2.5 µm particle size, under isocratic conditions consisting of a mobile phase of 50:45:5 water–acetonitrile–isopropanol with 1% ammonia at 0.2 mL/min. This method utilized a stable isotope internal standard with 11 deuterium atoms on the structure of the telaprevir molecule (telaprevir‐d11). An internal standard for the telaprevir‐R (telaprevir‐R‐d11) was also prepared by incubating telaprevir‐d11 in basic solution, which facilitated isomer inter‐conversion. The detection and quantitation of telaprevir, telaprevir‐R, telaprevir‐IS and telaprevir‐R‐IS was achieved by positive ion electrospray (ESI+) MS/MS detection. The assay quantifiable limit was 5.0 ng/mL when 0.100 mL of acidified human plasma was extracted. Accuracy and precision were validated over the calibration range of 5.0–5000 ng/mL. It was demonstrated using patient samples that, contrary to previous recommendations, quantitation of telaprevir does not require acidified plasma. Copyright © 2014 John Wiley & Sons, Ltd.
RNA Aminoacylation Mediated by Sequential Action of Two Ribozymes and a Nonactivated Amino Acid
Authors: Xu Jiacui , Appel Bettina , Balke Darko , Wichert Claudia , Müller Sabine
Published: April 2014

In the transition from the RNA world to the modern DNA/protein world, RNA‐catalyzed aminoacylation might have been a key step towards early translation. A number of ribozymes capable of aminoacylating their own 3′ termini have been developed by in vitro selection. However, all of those catalysts require a previously activated amino acid—typically an aminoacyl‐AMP—as substrate. Here we present two ribozymes connected by intermolecular base pairing and carrying out the two steps of aminoacylation: ribozyme 1 loads nonactivated phenylalanine onto its phosphorylated 5′ terminus, thereby forming a high‐energy mixed anhydride. Thereafter, a complex of ribozymes 1 and 2 is formed by intermolecular base pairing, and the “activated” phenylalanine is transferred from the 5′ terminus of ribozyme 1 to the 3′ terminus of ribozyme 2. This kind of simple RNA aminoacylase complex was engineered from previously selected ribozymes possessing the two required activities. RNA aminoacylation with a nonactivated amino acid as described here is advantageous to RNA world scenarios because initial amino acid activation by an additional reagent (in most cases, ATP) and an additional ribozyme would not be necessary.
N‐Diazo‐Bridged Nitroazoles: Catenated Nitrogen‐Atom Chains Compatible with Nitro Functionalities
Authors: Yin Ping , Parrish Damon A. , Shreeve Jean'ne M.
Published: April 2014

N‐diazo‐bridged azoles were synthesized based on oxidative coupling of N‐aminoazoles. Incorporation of extended catenated nitrogen‐atom chains with nitro groups led to compounds with favorable functional compatibilities. This combination gives rise to a series of high‐density energetic materials (HEDMs) with high heats of formation, enhanced densities, positive oxygen balances, and good detonation properties while retaining excellent thermal stabilities and relatively low impact sensitivities. Calculated and experimental studies showed the delicate balance between the length of the nitrogen atom chain, energetic performance, and inherent stability, thus, providing a promising strategy for designing advanced energetic materials.
Nutrient Enrichment and Hypoxia Threat in Urban Surface Water
Authors: Olatunde Olatunji S. , Olalekan Fatoki S. , Beatrice Opeolu O. , Bhekumusa Ximba J. , Zacheaus Ojekunle O. , Kehinde Adeniye N.
Published: April 2014

Water samples pooled from nine urban streams/rivers traversing high density residential and commercial areas in the Abeokuta metropolis, Ogun State, Nigeria, were investigated in order to determine the effect of inorganic nutrients on oxygen distribution between 2008 and 2010 by using standard methods. Results revealed that the metropolitan streams/rivers are anoxic and hypoxia‐threatened due to high nutrient load (NL) except in peri‐urban streams/river which served as control. The pH was 6.6–6.9 and the concentrations of dissolved organic carbon, total nitrogen and phosphorus (P‐PO43−) of the streams/rivers were 24.8–155.4, 3.82–15.46 and 1.35–5.71 mg/L, respectively, while dissolved oxygen (DO) ranged between 3.25 and 7.46 mg/L. The results also showed that the biochemical oxygen demand and chemical oxygen demand values ranged between 180.81 and 200.62, 250.27 and 312.83 mg/L, respectively. Analysis of variance showed significant differences between sampling sites as well as seasons (wet and dry) in terms of NL and oxygen levels in all the stream/river water samples investigated with those from residential locations having higher NL values during the dry season. Thus, DO levels in almost all the urban streams/rivers were low, hence the need for regulatory intervention to ensure point of compliance necessary to protect inland freshwater from sewage inlets.
P Accumulation Potential of Polygonum hydropiper Grown in High P Media
Authors: Ye Daihua , Li Tingxuan , Huang Xia , Zhang Xizhou , Zheng Zicheng , Yu Haiying
Published: April 2014

Plant‐assisted approaches are proven to be effective in ameliorating the ecological hazards of excessive phosphorus (P). P accumulation potentials in a mining ecotype (ME) and a non‐mining ecotype (NME) of Polygonum hydropiper were investigated in high P media. A field survey revealed that biomass, P concentration, and accumulation in shoots of ME were significantly greater than that of NME. ME and NME grown in hydroponic media with a series of P supplies ranging from 50 to 800 mg P L−1 showed significant increases in shoot biomass, P concentration, and P accumulation with ascending P supplied level. In manure wastewater media, shoot biomass, and P accumulation of ME increased with the growth period prolonged and revealed significant advantages compared to NME at day 45. Acid phosphatase and phytase of both ecotypes at P‐sufficient media were superior to those at 50 mg P L−1, but NME was higher than ME in the hydroponic media. The activities of acid phosphatase and phytase in ME grown in high concentration wastewater were greater in comparison with that in low concentration wastewater. These results indicate that P. hydropiper can be able to extract P from high P media, and P accumulation potential of ME performs better than that of NME in the media where organic P exists.
Solid‐State Perovskite‐Sensitized p‐Type Mesoporous Nickel Oxide Solar Cells
Authors: Tian Haining , Xu Bo , Chen Hong , Johansson Erik M. J. , Boschloo Gerrit
Published: April 2014

Perovskite has been adopted as photosensitizer to develop solid state p‐type mesoporous nickel oxide (NiO) dye‐sensitized solar cells (DSCs) employing PCBM as electron conductor. The optimal device achieved an efficiency of 1.5 % with an impressive open circuit voltage of more than 800 mV, which is the record of solar cell based on p‐type mesoporous NiO electrode. This result shows the potential for building highly efficient p‐type NiO solar cells as stand‐alone device.
Enhancing secrecy capacity of multi‐relay wiretap systems with partial channel state information
Authors: Long Hang , Xiang Wei , Wang Jing , Zhang Xiaoli , Wang Wenbo
Published: April 2014

Distributed precoding has provento be capable of enhancing the secrecy capacity of the multi‐relay wiretap system. An iterative distributed precoding and channel state information (CSI) sharing scheme can be used to reduce the CSI overhead at each relay node. However, in practical applications, the CSI of each relay node cannot be perfectly known to themselves, especially that of the relay‐eavesdropper channels. Thus, partial CSI for the relay‐eavesdropper links is assumed, and the corresponding distributed precoding and CSI sharing schemes are investigated. Under the assumption that the average value of the relay‐eavesdropper channel is known at each relay node, an extended iterative distributed precoding and CSI sharing scheme is proposed. Simulation results demonstrate that with the increase of the power ratio of the constant part to the random part of the relay‐eavesdropper channels, the proposed scheme with partial CSI performs increasingly close to the one with perfect CSI in secrecy capacity. Copyright © 2014 John Wiley & Sons, Ltd.
Demodulation of time series highlights impacts of hydrologic drivers on the Everglades ecosystem
Authors: Foti Romano , del Jesus Manuel , Rinaldo Andrea , Miralles‐Wilhelm Fernando R. , Rodriguez‐Iturbe Ignacio
Published: April 2014

In the context of climatic uncertainty and potential climatic change, incorporating climatic variability and change in eco‐hydrological analysis, as well as understanding the impact of such variability on ecosystems, is of crucial importance. The latter is particularly true for those complex ecosystems, such as wetlands, which cradle large varieties of species, many of which rare or endangered. Focusing on the Everglades wetlands, we investigate the presence of non‐stationary elements in the seasonal cycle of precipitation, temperature and stage level and examine their correlation and potential impact on the ecosystem's flora and fauna. To this aim, we revisit demodulation techniques and demonstrate their validity for the diagnosis of long‐term trends in the amplitude and phase of seasonal patterns of hydrologic series. We then analyse historical records of fauna and flora components of the Everglades in order to reveal potential relationships with hydrological trends. We observe that the seasonal patterns of all the time series analysed are non‐stationary. In addition, we observe that the amplitude of seasonal oscillations of all hydro‐climatic drivers is strongly correlated with anomalies in records of wading birds population and plant carbon assimilation. Copyright © 2014 John Wiley & Sons, Ltd.
DRIFT and Theoretical Studies of Ethylene/Ethane Separation on Flexible and Microporous [Cu2(2,3‐pyrazinedicarboxylate)2(pyrazine)]n
Authors: Kishida Keisuke , Watanabe Yumiko , Horike Satoshi , Watanabe Yoshihiro , Okumura Yoshikuni , Hijikata Yuh , Sakaki Shigeyoshi , Kitagawa Susumu
Published: April 2014

The separation of olefins from paraffin is important for the production of industrial chemicals. Therefore, there is a need for a better separation system such as a pressure‐swing adsorption (PSA) process. With regard to adsorbents that enable gas separation by PSA, CPL‐1 {[Cu2(2,3‐pyrazinedicarboxylate)2(pyrazine)]n} is an attractive porous material because of the flexibility and microporosity of the material, which provides it with a unique guest‐responsive nature. Adsorption isotherm studies were conducted to elucidate the ethylene‐selective adsorption properties of CPL‐1, which was further examined by breakthrough experiments with ethylene–ethane binary gas mixtures at near room temperatures. Spectroscopic and computational approaches used to investigate the interaction between CPL‐1 and the C2 gas molecules suggested that hydrogen bonds are important in the selective adsorption of ethylene over ethane.
Palladium‐Catalyzed Dithiolation of Platinum(II) Alkynylarylacetylides with Diphenyl Disulfide Leading to Construction of π‐Conjugated Systems with Platinum and Thio Groups
Authors: Rahman Md. Mostafizur , Nomoto Akihiro , Younus Muhammad , Ogawa Akiya
Published: April 2014

π‐Conjugated systems consisting of platinum, sulfur, alkyne, and arene units were synthesized by palladium‐catalyzed addition of organic disulfides to platinum acetylides. When diphenyl disulfide was treated with platinum(II) complexes containing extended alkynyl ligands, trans‐(R3P)2Pt(C≡C–Ar–C≡C–H)2, in the presence of Pd(PPh3)4 catalyst, new sulfur‐containing platinum(II) bis(alkenylarylacetylide) complexes were regioselectively synthesized in good yields. The absorption and luminescence spectra indicated that the emission exhibited in the range 411–415 nm depends on the nature of the acetylide ligand bound to platinum.
Copper‐Catalyzed C(sp3)–C(sp2) Cross‐Coupling: Synthesis of 4‐Aryl‐2‐alkyl­amino‐3‐nitro‐4H‐chromenes
Authors: Rao H. Surya Prakash , Rao A. Veera Bhadra
Published: April 2014

Inexpensive copper(II) acetate effectively catalyzes cross‐coupling of electron‐deficient as well as electron‐rich arylboronic acids with 4‐methylsulfanyl‐2‐alkylamino‐3‐nitro‐4H‐chromenes under near neutral conditions at room temp. to furnish a range of 4‐aryl‐4H‐chromenes. This new strategy enabled substitution of the C(4)SMe group present on a sp3 hybridized carbon of the 4H‐chromenes with aryl/heteroaryl groups. Mechanistic probing revealed that the CuI–CuIII cycle is involved in catalysis. One‐pot sequential substitution of C(4)SMe followed by C(6)Br with aryl groups has been achieved through Cu(OAc)2 and Pd2(dba)3 (Suzuki coupling) catalysis.
Total Synthesis of Carbazomycin G by a Thermal Ring Expansion/Self‐Redox Reaction Cascade
Authors: An Yong , Wang Yunxia , Hu Xiangdong
Published: April 2014

The total synthesis of carbazomycin G (7) has been accomplished in six steps and 26 % overall yield starting from commercially available materials. As an efficient access to the tricyclic skeleton of carbazomycins A–H, an interesting thermal ring expansion/self‐redox reaction cascade of intermediate 11 has been developed in our study. The self‐redox reaction of intermediate 10 can be readily accelerated in the presence of triethylamine, and a plausible reaction mechanism for this process has been proposed. Finally, the synthesis of carbazomycin G was completed by the widely applied regioselective methylation reaction.