bluuebunny/crossref_metadata_2025 huggingface dataset:
A method for antenna gain measurements in nonanechoic sites
Authors: Tamas Razvan D. , Deacu Daniela , Vasile Gabriel , Ioana Cornel
Published: April 2014

A measuring technique for antenna gain is presented, based on averaging a normalized transfer function over a distance range. Criteria for setting the distance range are drawn by investigating the effects of reflection and diffraction. Our method is compared to the time‐gating method by measuring two low‐gain, quasi nondirectional antennas. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1553–1557, 2014
MIMO application UWB antenna doublet incorporating a sinusoidal decoupling structure
Authors: Bilal Muhammad , Saleem Rashid , Shafique Muhammad F. , Khan Hassan A.
Published: April 2014

In this article, a miniaturized multiple input and multiple output antenna doublet is proposed for the ultrawideband communication. Two semielliptical antenna elements having semicircular parasitic patches/defected ground planes, sine‐curve based meander‐line parasitic structures, and smoothly tapered feed lines are proposed in this article. Moreover, a sine‐curve based nested T‐shaped decoupling structure is used to achieve a decoupling/isolation of at least 20 dB over most of the frequency band. More importantly, the proposed design has a compact size of 30 × 50.5 mm2. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1547–1553, 2014
Design of a planar wideband patch antenna for UHF RFID tag
Authors: Bashri Mohd Saiful Riza , Ibrahimy Muhammad Ibn , Motakabber S. M. A.
Published: April 2014

In this article, a planar wideband microstrip patch antenna for ultrahigh frequency (UHF) radio identification (RFID) tag is presented. By incorporating two resonating C‐shape patches, two resonances are excited close to each other to create wide impedance bandwidth to cover the entire operating frequency of UHF RFID system between 860 and 960 MHz for universal metal mountable tag. For complex impedance matching between the antenna input terminal and the referenced microchip whose impedance is Zchip = (31 − j212) Ω, a small rectangular loop feed structure was utilized where both of the resonating patches are magnetically coupled. The antenna design and simulation were carried out using finite element method based software, Ansoft HFSS v13. The simulated and measured radiation patterns at operating frequency of 915 MHz are in good agreement. The simulated and measured impedance bandwidth (Return Loss ≥ 3 dB) of 159 and 155 MHz were obtained that are well above the required 100 MHz bandwidth. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1579–1584, 2014
Compact balanced UWB bandpass filter with one narrow notched band
Authors: Wei Feng , Jay Guo Y. , Shi Xiao Wei
Published: April 2014

A compact balanced ultra‐wideband bandpass filter (BPF) with one sharply notched band is presented in this article. The proposed BPF based on microstrip‐to‐slotline transition obtains favorable uniform differential‐mode response and good common‐mode suppression. Moreover, one narrow notched band with a 3 dB bandwidth of 6.8% is realized by introducing one coupled half‐wavelength resonator. The fabricated filter has a more than 25% size reduction compared to the designs reported in open literature. The predicted results are compared with measured ones and good agreement is achieved. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1626–1629, 2014
Frequency tuning and miniaturizations of a bandwidth enhanced rectangular microstrip antenna
Authors: Chakraborty Ujjal , Chowdhury Santosh K. , Bhattacharjee Anup K.
Published: April 2014

The effect of a rectangular ground slot (RGS) is investigated in a small‐sized microstrip antenna embedded with two rectangular and one half‐U open ended slots. It is observed that the resonance frequency of the proposed antenna can be tuned from 6.096 GHz down to 3.51 GHz by changing the length parameter of the RGS. The maximum impedance bandwidth is obtained about 16.02% for the size reduction of 42.44% and maximum size reduction is 81.48% for the impedance bandwidth of 5.24%. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1600–1603, 2014
Compact quad‐band BPF based on stub loaded double‐ring resonator
Authors: Wei Feng , Wei Shi Xiao
Published: April 2014

A compact quad‐band band‐pass filter (BPF) based on a single stub loaded double‐ring resonator (SL‐DRR) is presented in this article. The proposed SL‐DRR, which can introduce four narrow passbands simultaneously, is investigated using even/odd mode analysis. As an example, a BPF centered at 1.57, 2.8, 5.2, and 5.9 GHz is designed and it achieves a more than 45% size reduction compared to the designs reported in open literature. Theoretical and simulated results are presented, which are in good agreement with the measured ones. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1633–1635, 2014
A new compact quad‐band bandpass filter using quad‐mode stub loaded resonator
Authors: Weng Min‐Hang , Ye Chang‐Sin , Su Yan‐Kuin , Lan Siang‐Wen
Published: April 2014

A new compact quad‐band microstrip bandpass filter designed using a quad‐mode stub‐loaded resonator (SLR) is proposed. The equivalent circuit of the SLR consists of one even mode and two odd resonant modes, used to create passbands operated at 1.8, 2.4, 3.5, and 5.2 GHz, corresponding to global system for mobile communications, wireless local area networks, and worldwide interoperability for microwave access applications. The filter is compact in size because only two sets of resonator are used by means of the quad‐mode behaviors. Furthermore, 0° feed structures is used to set at least one transmission zero on each side of each passband, resulting in high skirt selectivity. Experimental results show good agreement with the simulated results. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1630–1632, 2014
Optimum design of Wpt relay system by controlling capacitance
Authors: Kim Ju‐Hui , Park Byung‐Chul , Lee Jeong‐Hae
Published: April 2014

This article presents an optimum design method of a wireless power transfer (WPT) relay system. Magnetic couplings between nonadjacent resonators cause a frequency shifting of maximum efficiency in a WPT relay system. Thus, the efficiency at the system frequency of f0 is relatively lower than that at a shifted frequency of f′. To use the system at f0 effectively, the values of capacitors of resonators are optimized. The appropriate values of capacitors are found from the genetic algorithm by analytic calculation. This optimum design method is verified by both simulation and measurement. Additionally, the currents and dissipated powers on the resonators are investigated to explain the mechanism of optimization. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1658–1661, 2014
RHCP pattern‐reconfigurable spiral antenna biased with two DC signals
Authors: Gong Liang , Yang Yi , Chan King Y. , Ramer Rodica
Published: April 2014

A right‐hand circularly polarized beam steering spiral antenna is presented in this article. It is designed using the standard p‐i‐n technology, enhanced with arm switches and biasing lines. The ensuing design is easily manufactured and is functionally competitive with the more complex ones, based on RF‐MEMS. Three beams, tilted 40° with respect to the spiral central axis, are generated at 3.3 GHz, suitable for WiMax systems at this frequency. These beams are directed at approximately 90°, 180°, and 270° in the azimuth space. Beam directions depend on various configurations of the seven p‐i‐n diodes added to the spiral structure. The states of the diodes are subjected to the two DC bias voltages connected to the spiral arm. The radiation performance over the 200‐MHz bandwidth (3.2–3.4 GHz) is relatively stable. Measurements in this band show the reflection coefficient below −10 dB and the axial ratio below or close to 3 dB at the peak beam directions. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1636–1640, 2014
A dual‐band balanced amplifier using three‐layer technology
Authors: Hou Zhangju , Chiu Leung
Published: April 2014

A multilayer technology is applied to design a dual‐band branch‐line coupler for the dual‐band balanced amplifier. The proposed coupler is designed based on a three‐layer printed circuit board. The dual‐band operation is achieved by four additional shunt stubs at the middle layer, while the upper layer is the core and active circuits layer and the bottom is ground layer. The proposed coupler with equal power division is designed at two frequencies of 1.1 and 1.9 GHz. Besides, a balanced amplifier is also designed which achieves gain of 11.6 and 10.1 dB at 1.1 and 1.9 GHz, respectively. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1680–1683, 2014
Coupled‐sectorial‐loop antenna with circular sectors for super wideband applications
Authors: Yeo Junho , Lee Jong‐Ig
Published: April 2014

A coupled‐sectorial‐loop antenna (CSLA) with circular sectors is presented for super wideband (SWB) applications. Conventional CSLA consists of two parallel sectorial loop antennas connected along an axis of symmetry and triangular sectors are used. The average input impedance of the conventional CSLA is over 100 Ω, and a half of the CSLA above a ground plane is used to match with a 50‐Ω feed line. In the proposed antenna, circular sectors are used instead of triangular sectors to directly match with the 50‐Ω feed line, and the full structure of the CSLA is used. A prototype of the proposed antenna is fabricated on an FR4 substrate, and its performance is compared to the conventional CSLA. The experimental results show that the frequency band for a voltage standing wave ratio < 2.15 is 1.0–19.4 GHz (180.4%), which satisfies the requirement of the SWB antenna. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1683–1689, 2014
Design and characterization of a novel diamond resonator
Authors: Maricar Mohamed Ismaeel , Glover James , Evans Gwynne , Ata‐ul‐Khalid  , Cumming David , Oxley Chris
Published: April 2014

In this article, the resonant frequency and quality factor of a novel coplanar waveguide (cpw) diamond‐shaped resonator were analyzed using advanced design system‐2009 momentum model software. The diamond resonator was compared with the cpw radial stub resonator on gallium arsenide (GaAs); the work indicated that the diamond resonator had a smaller physical size and higher quality factor (Q) at millimetric wave frequencies. Experimentally measured diamond cpw resonators fabricated on GaAs were in good agreement with the simulated results. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1691–1693, 2014
Development of passive millimeter wave imaging for concealed weapon detection indoors
Authors: Shi Xiang , Yang M.H.
Published: April 2014

The passive millimeter wave (PMMW) imaging is often successful for outdoors as radiation of natural sky (cold source) provides the required contrast for imaging. When this method is used indoors, to detect weapons hidden inside the human body they fail detection due to the contrast between the target and subject being not obvious from lack of sky radiation. An active illumination although provides the desired contrast for the image recognition, but cause the image “blind” and “flicker” resulting in poor quality of imaging and target identification. This article describes a PMMW imaging security systems suitable for indoor usage. This system includes a large‐diameter parabolic antenna for convergence of target radiation, a front end array consisting of 9 94 GHz imaging radiometer, eight Ka‐band source with discrete frequency and discrete radiation direction to radiating harmonic illumination, and provide affordable energy “like noise” radiation, avoiding image's glint under coherent radiation. The results obtained from experiments on indoor detection of concealed weapon in human body validate the theory of proposed imaging systems, its feasibility, and practical utility. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1701–1706, 2014
A novel three vector sum active phase shifter design for W‐band automotive radar applications
Authors: Öztürk Efe , Tekin İbrahim
Published: April 2014

This article presents a novel active W‐band phase shifter implemented using IHP SiGe Heterojunction Bipolar Transistor (HBT) 0.25‐µm SG25H1 technology with three vector (0°‐120°‐240°) sum technique. The integrated chip consists of a 3‐way Wilkinson power divider/combiner with 0°‐120°‐240° phase shifting lines and three low‐noise amplifiers (LNA) working at 77 GHz, which comprises a total of 1.5 × 1.1 mm2 die area. The phase shifting is based on the weighted sum of three vectors which have 120°‐angle separation so that all 360° could be scanned with simple amplitude control only. The LNAs are fabricated using IHP technology and can be used successfully in the active phase shifter design. LNA measurement results show that a variable gain of 0–14 dB at 77 GHz can be obtained by sweeping the base voltage between 1.8 and 2.3 V. The simulation results of complete system, including power dividers, phase shifting lines, LNAs, power combiners show that phase can be adjusted by 360° with a maximum gain of 1.8 dB. Input/output return loss for all the possible phase states are below 15 dB. The proposed phase shifter can be used in W‐band applications for full scan of 360°. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1715–1720, 2014
Spectral line suppression capabilities of spectral line free convolutional codes in UWB over fiber systems
Authors: Perez‐Ramos Aldo E. , Villarreal‐Reyes Salvador , Arvizu‐Mondragon Arturo , Lepers Catherine , Santos‐Aguilar Joel
Published: April 2014

The topic of spectral line suppression is of major importance when designing impulse radio ultrawideband (IR‐UWB) systems. The presence of spectral lines in the power spectral density (PSD) may limit the maximum transmission power to comply with UWB regulations, thus, affecting the system performance. Although previous works have shown the advantages of IR‐UWB over fiber (UWBoF) implementations, the topic of spectral line suppression in PSD in such systems has not been entirely addressed. This letter proposes a simple IR‐UWBoF system using spectral line free (SLF) convolutional codes to address this topic. Experimental results show that the proposed system offers improved PSD characteristics compared to conventional IR‐UWBoF implementations. Furthermore, it is demonstrated that the proposed system is able to deliver SLF IR‐UWB signals over single‐mode fibers up to 30 km. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1712–1715, 2014
Erratum: New compact E‐plane microstrip‐to‐waveguide transition with slotted ground plane coupling
Authors: Gholami Mehrad , Yagoub M. C. E.
Published: April 2014

In this article, a new compact microstrip‐to‐waveguide transition is presented. With 10% bandwidth for 20‐dB return loss and 0.2‐dB insertion loss, the proposed X‐ and Ku‐band designs are insensitive to manufacturing tolerances. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:615–619, 2014; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.28179. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1729, 2014
Blind multirigid retrospective motion correction of MR images
Authors: Loktyushin Alexander , Nickisch Hannes , Pohmann Rolf , Schölkopf Bernhard
Published: April 2014

Purpose

Physiological nonrigid motion is inevitable when imaging, e.g., abdominal viscera, and can lead to serious deterioration of the image quality. Prospective techniques for motion correction can handle only special types of nonrigid motion, as they only allow global correction. Retrospective methods developed so far need guidance from navigator sequences or external sensors. We propose a fully retrospective nonrigid motion correction scheme that only needs raw data as an input.

Methods

Our method is based on a forward model that describes the effects of nonrigid motion by partitioning the image into patches with locally rigid motion. Using this forward model, we construct an objective function that we can optimize with respect to both unknown motion parameters per patch and the underlying sharp image.

Results

We evaluate our method on both synthetic and real data in 2D and 3D. In vivo data was acquired using standard imaging sequences. The correction algorithm significantly improves the image quality. Our compute unified device architecture (CUDA)‐enabled graphic processing unit implementation ensures feasible computation times.

Conclusion

The presented technique is the first computationally feasible retrospective method that uses the raw data of standard imaging sequences, and allows to correct for nonrigid motion without guidance from external motion sensors. Magn Reson Med 73:1457–1468, 2015. © 2014 Wiley Periodicals, Inc.
Motivational orientations of non‐traditional adult students to enroll in a degree‐seeking program
Authors: Francois Emmanuel Jean
Published: April 2014

The purpose of this research was to investigate the motivational orientations of non‐traditional adult students to enroll in a degree‐seeking program based on their academic goal. The Education Participation Scale (EPS) was used to measure the motivational orientations of participants. Professional advancement, cognitive interest, and educational preparation were found to be the dominant motivational orientations of non‐traditional adult college students. There were significant differences in motivational orientations among associate, bachelor's, master's, and doctoral degree students. The findings from this study provide opportunities for instructors and administrators in higher education to use motivational orientations data in designing recruitment materials and activities for their program as well as in adopting curriculum and instruction strategies to increase students’ motivation toward learning.
Understanding generational diversity: Strategic human resource management and development across the generational “divide”
Authors: Amayah Angela Titi , Gedro Julie
Published: April 2014

There are more generations in today's workforce than ever before, which has the possibility to create challenges for Human Resource professionals. The purpose of this article is to interrogate existing stereotypes and generalities about the characteristics of different generations with respect to the workplace, and to offer suggestions for Human Resource professionals to help organizations successfully negotiate a multi‐generational workforce. A wide range of studies published in the last seven years is reviewed, in order to develop a taxonomy of generational issues and their implications for Human Resource Managers and Human Resource Developers. The article is framed by the following taxonomic dimensions: organizational citizenship behaviors, work values, work attitudes, motivation, psychological traits, and technology.
Multi‐stakeholder public policy and governance in China: an analysis
Authors: Millar Carla C. J. M. , Mahon John F.
Published: April 2014

In this article, public policy is put into a multi‐stakeholder rather than adversarial perspective: we argue that there is a role for multi‐stakeholder involvement in both the development and implementation of public policy; these are separate processes that can involve different patterns of stakeholder involvement (stakeholders have different skills and levels of interest in public policy) in either one or both the development and implementation phases. We need new models, approaches and examples of such multi‐stakeholder public policy, and in this Special Issue, we focus on China, where such research is only slowly emerging. We present and analyse six papers that fall naturally into three categories: (1) corporate social responsiveness and societal relationships; (2) public affairs (particularly reputation management) and citizen involvement; and (3) public‐management‐oriented, data‐based analyses. These articles, taken together, increase our understanding of multi‐stakeholder research and practice, but equally as important, they give us insights into how Chinese public policy academics research and report public policy. This window into academic research and thinking offers us an opportunity to expand and deepen our understanding of public policy and its implications for public affairs in China. Copyright © 2014 John Wiley & Sons, Ltd.
Iatrogenic Cushing Syndrome Secondary to a Probable Interaction Between Voriconazole and Budesonide
Authors: Jones Whitney , Chastain Cody A. , Wright Patty W.
Published: April 2014

Oral budesonide is commonly used for the management of Crohn's disease given its high affinity for glucocorticoid receptors and low systemic activity due to extensive first‐pass metabolism through hepatic cytochrome P450 (CYP) 3A4. Voriconazole, a second‐generation triazole antifungal agent, is both a substrate and potent inhibitor of CYP isoenzymes, specifically CYP2C19, CYP2C9, and CYP3A4; thus, the potential for drug‐drug interactions with voriconazole is high. To our knowledge, drug‐drug interactions between voriconazole and corticosteroids have not been specifically reported in the literature. We describe a 48‐year‐old woman who was receiving oral budesonide 9 mg/day for the management of Crohn's disease and was diagnosed with fluconazole‐resistant Candida albicans esophagitis; oral voriconazole 200 mg every 12 hours for 3 weeks was prescribed for treatment. Because the patient experienced recurrent symptoms of dysphagia, a second 3‐week course of voriconazole therapy was taken. Seven weeks after originally being prescribed voriconazole, she came to her primary care clinic with elevated blood pressure, lower extremity edema, and weight gain; she was prescribed a diuretic and evaluated for renal dysfunction. At a follow‐up visit 6 weeks later with her specialty clinic, the patient's blood pressure was elevated, and her physical examination was notable for moon facies, posterior cervical fat pad prominence, and lower extremity pitting edema. Iatrogenic Cushing syndrome due to a drug‐drug interaction between voriconazole and budesonide was suspected, and voriconazole was discontinued. Budesonide was continued as previously prescribed for her Crohn's disease. On reevaluation 2 months later, the patient's Cushingoid features had markedly regressed. To our knowledge, this is the first published case report of iatrogenic Cushing syndrome due to a probable interaction between voriconazole and oral budesonide. In patients presenting with Cushingoid features who have received these drugs concomitantly, clinicians should consider the potential drug interaction between these agents, and the risks and benefits of continued therapy must be considered.
Enzymatic “tricks”: Carboxylate shift and sulfur shift
Authors: Sousa Sérgio F. , Cerqueira Nuno M. F. S. A. , Brás Natércia F. , Fernandes Pedro A. , Ramos Maria J.
Published: April 2014

We look into two interesting phenomena that occur in enzymes: one has been termed carboxylate shift and the other sulfur shift. Carboxylate shift is an interesting mechanistic phenomenon, which is characterized by a change in the coordination mode of a carboxylate group (monodentate to bidentate or vice versa) with ligand entrance or ligand exit from the metal coordination sphere. We focus on some patterns relating the intrinsic characteristics of a given metal coordination sphere to the occurrence of a carboxylate shift and the corresponding energy stabilization suffered by the enzyme. A structural rearrangement known as sulfur shift has been recognized to occur in some Mo‐containing enzymes of the DMSO reductase family. This mechanism is characterized by the displacement of a coordinating cysteine thiol or selenocysteine thiol from the first to the second shell of the Mo‐coordination sphere metal, allowing for direct coordination of the incoming ligand (substrate or inhibitor) to the hexacoordinated Mo ion found in the enzyme unbound state. The sulfur shift, as well as the carboxylate shift, results in a rearrangement of the enzymatic catalytic center that provides an efficient mechanism to keep a constant coordination number throughout an entire catalytic pathway. © 2014 Wiley Periodicals, Inc.
Autonomous Black Hawk in Flight: Obstacle Field Navigation and Landing‐site Selection on the RASCAL JUH‐60A
Authors: Whalley Matthew S. , Takahashi Marc D. , Fletcher Jay W. , Moralez Ernesto , Ott LTC Carl R. , Olmstead LTC Michael G. , Savage James C. , Goerzen Chad L. , Schulein Gregory J. , Burns Hoyt N. , Conrad Bill
Published: April 2014

This paper describes the development and flight test of autonomous obstacle field navigation and safe landing area selection on the U.S. Army Aeroflightdynamics Directorate RASCAL JUH‐60A research helicopter. Using laser detection and ranging (LADAR) as the primary terrain sensor, the autonomous flight system is able to avoid obstacles, including wires, and select safe landing sites. An autonomous integrated landing zone approach profile was developed and validated that integrates cruise flight, low‐level terrain flight, and approach to a safe landing spot determined on the fly. Results are presented for a range of sites and conditions. Approximately 750 km of autonomous flight was performed, 230 km of which was at low altitude in mountainous terrain using the obstacle field navigation system. This is the first time a full‐scale helicopter has been flown fully autonomously a significant distance in low‐level flight over complex terrain, basing its planning solely on sensor data gathered from an onboard sensor. These flights demonstrate tight integration between terrain avoidance, control, and autonomous landing.
A modest proposal for dropping poor arms in clinical trials
Authors: Proschan Michael A. , Dodd Lori E.
Published: April 2014

This paper presents a simple procedure for clinical trials comparing several arms with control. Demand for streamlining the evaluation of new treatments has led to phase III clinical trials with more arms than would have been used in the past. In such a setting, it is reasonable that some arms may not perform as well as an active control. We introduce a simple procedure that takes advantage of negative results in some comparisons to lessen the required strength of evidence for other comparisons. We evaluate properties analytically and use them to support claims made about multi‐arm multi‐stage designs. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.
Step‐up testing procedure for multiple comparisons with a control for a latent variable model with ordered categorical responses
Authors: Lin Yueqiong , Kwong Koon Shing , Cheung Siu Hung , Poon Wai‐Yin
Published: April 2014

In clinical studies, multiple comparisons of several treatments to a control with ordered categorical responses are often encountered. A popular statistical approach to analyzing the data is to use the logistic regression model with the proportional odds assumption. As discussed in several recent research papers, if the proportional odds assumption fails to hold, the undesirable consequence of an inflated familywise type I error rate may affect the validity of the clinical findings. To remedy the problem, a more flexible approach that uses the latent normal model with single‐step and stepwise testing procedures has been recently proposed. In this paper, we introduce a step‐up procedure that uses the correlation structure of test statistics under the latent normal model. A simulation study demonstrates the superiority of the proposed procedure to all existing testing procedures. Based on the proposed step‐up procedure, we derive an algorithm that enables the determination of the total sample size and the sample size allocation scheme with a pre‐determined level of test power before the onset of a clinical trial. A clinical example is presented to illustrate our proposed method. Copyright © 2014 John Wiley & Sons, Ltd.
A Tomo‐PIV study of the effects of freestream turbulence on stall delay of the blade of a horizontal‐axis wind turbine
Authors: Lee Hsiao Mun , Wu Yanhua
Published: April 2014

Volumetric velocity fields were measured using tomographic particle image velocimetry on a model of the blade of a 5 kW horizontal‐axis wind turbine to study the effects of freestream turbulence levels (FTLs) at 0.4%, 4% and 13% on stall delay phenomenon at two different global tip speed ratios of 3 and 5 with Reynolds number (Re) ࣈ 5000. Static pressures were measured, and results illustrated that FTL has stronger effect on the surface pressures of the static airfoil. Magnitudes of the absolute velocities within the separated flows above the static airfoil's suction surface increase significantly with higher FTL, while the changes of these velocities above the rotating blade's surface are less obvious. Radial flows from rotating blade's root to tip were also observed with strong spanwise velocity component located in the vicinities of the vortices. At the root and middle sections of the rotating blade, the flows with strong radial velocity component, w, become wider with higher FTL near to the rotating blade's leading edge when the angles of attack (AOAs) are large. At large AOAs, the strength and size of the vortices shed from the rotating blade's leading and trailing edges decrease significantly with higher FTL. However, at small AOAs, the size and coherence of the vortices near the rotating blade's trailing edge increase significantly with higher FTL. Surface streamlines of the rotating blade illustrated that at the rotating blade's root region and at large AOAs, the streamlines tend to lean toward the rotating blade's trailing edge at higher FTL. Copyright © 2014 John Wiley & Sons, Ltd.
Withanolides are Potent Novel Targeted Therapeutic Agents Against Adrenocortical Carcinomas
Authors: Subramanian Chitra , Zhang Huaping , Gallagher Robert , Hammer Gary , Timmermann Barbara , Cohen Mark
Published: April 2014

Background

Adrenocortical carcinoma (ACC) is a rare and aggressive malignancy with poor prognosis, as a majority of patients present with advanced disease. Current adjuvant strategies for metastatic patients include mitotane or other cytotoxic agents and carry a significant morbidity as well as a low (<10 %) 5‐year survival. Withanolides, including withaferin A, are novel chemotherapeutic agents with potent targeted effects in medullary thyroid cancer and a number of solid malignancies with low toxicity in vivo. We hypothesize that novel naturally derived withanolides will have potent targeted anti‐cancer activity against ACCs.

Methods

In vitro cell viability of ACC cell lines (Y1 and SW13) was measured using MTS cell proliferation assay. Cell cycle and apoptotic analysis studied using annexin V/propidium iodide staining on flow cytometry (FC) and targeted molecular mechanisms of withanolide cytotoxicity were assessed using standard Western blot analysis.

Results

All the withanolides potently reduced ACC cell viability on MTS assay with 7‐ to 185‐fold higher selectivity than normal fibroblasts. Cell cycle analysis demonstrated a shift in cell cycle arrest from G1/G0 to G2/M with induction of apoptosis at nanomolar concentrations of withanolides. Unlike current ACC therapeutics, withanolides modulated expression of several key oncogenic pathway proteins in ACCs by Western blot, including Jagged 1, MAPK, and Akt/mTOR pathway proteins in a dose‐dependent manner after 24 h drug treatment of SW13 cells.

Conclusion

These results demonstrate the first evidence of the anticancer efficacy of withanolides in ACC cells and provide support for future translational evaluation of these compounds as novel therapeutic agents for ACC patients.
History and Evolution of Surgical Ethics: John Gregory to the Twenty‐first Century
Authors: Namm Jukes P. , Siegler Mark , Brander Caroline , Kim Tae Yeon , Lowe Christian , Angelos Peter
Published: April 2014

As surgery grew to become a respected medical profession in the eighteenth century, medical ethics emerged as a response to the growing need to protect patients and maintain the public’s trust in physicians. The early influences of John Gregory and Thomas Percival were instrumental in the formulation of patient‐centered medical ethics. In the late nineteenth century, the modern surgical advances of anesthesia and antisepsis created the need for a discipline of ethics specific to surgery in order to confront new and evolving ethical issues. One of the founding initiatives of the American College of Surgeons in 1913 was to eliminate unethical practices such as fee‐splitting and itinerant surgery. As surgery continued to advance in the era of solid organ transplantation and minimally invasive surgery in the latter half of the twentieth century, surgical innovation and conflict of interest have emerged as important ethical issues moving forward into the twenty‐first century. Surgical ethics has evolved into a distinct branch of medical ethics, and the core of surgical ethics is the surgeon–patient relationship and the surgeon’s responsibility to advance and protect the well‐being of the patient.
CreatingQungasvik(A Yup'ik Intervention “Toolbox”): Case Examples from a Community‐Developed and Culturally‐Driven Intervention
Authors: Rasmus Stacy M. , Charles Billy , Mohatt Gerald V.
Published: April 2014

This paper describes the development of a Yup'ik Alaska Native approach to suicide and alcohol abuse prevention that resulted in the creation of theQungasvik, a toolbox promoting reasons for life and sobriety among youth. TheQungasvikis made up of thirty‐six modules that function as cultural scripts for creating experiences in Yup'ik communities that build strengths and protection against suicide and alcohol abuse. TheQungasvikmanual represents the results of a community based participatory research intervention development process grounded in culture and local process, and nurtured through a syncretic blending of Indigenous and Western theories and practices. This paper will provide a description of the collaborative steps taken at the community‐level to develop the intervention modules. This process involved university researchers and community members coming together and drawing from multiple sources of data and knowledge to inform the development of prevention activities addressing youth suicide and alcohol abuse. We will present case examples describing the development of three keystone modules;Qasgiq(The Men's House),Yup'ik Kinship Terms, andSurviving Your Feelings. These modules each are representative of the process that the community co‐researcher team took to develop and implement protective experiences that: (1) create supportivecommunity, (2) strengthenfamilies, and (3) giveindividualstools to be healthy and strong.
Biological cycle of silicon in moso bamboo (Phyllostachys pubescens) forests in central Japan
Authors: Umemura Mitsutoshi , Takenaka Chisato
Published: April 2014

Silicon (Si) has various biogeochemical functions, such as regulating soil formation and species composition, not only in terrestrial ecosystems but also in aquatic ones. Bamboo stands accumulate large quantities of amorphous Si. Evaluating Si dynamics in moso bamboo (Phyllostachys pubescens) forests, which are currently spreading through eastern Asia, is important in understanding their biogeochemical function as a supply source of phytoliths. We conducted a study on the organic accumulation and biological cycle of Si in three P. pubescens stands in central Japan with different site characteristics. The amounts of Si accumulation aboveground and underground were 200–360 and 180–460 kg/ha, respectively. These values indicate that Si accumulation underground was comparable to that aboveground. Silicon supply to the forest floor through litterfall was 77–330 kg/ha/year corresponding to 165–706 kg/ha/year as phytoliths (SiO2), and 72–88 % was supplied as leaf litter. These results showed that a huge biogenic Si pool derived from bamboo plants exists in the floor of bamboo forests. Furthermore, we estimated the Si turnover time in P. pubescens forests as being 1.3–12.2 years, although this variation may depend on forestry conditions such as soil water content or stem density.
A Primary Method for the Determination of Hydroxyl Value of Polyols by Fourier Transform Mid‐Infrared Spectroscopy
Authors: Tavassoli‐Kafrani M. H. , Curtis J. M. , van de Voort F. R.
Published: April 2014

A primary Fourier transform infrared (FTIR) method was developed to determine the hydroxyl value (OHV) of polyols produced from edible oils. The method is a modification of American Society for Testing and Materials 1899‐08, using toluene as the solvent to dissolve the sample and to carry the reactive reagent p‐toluenesulfonyl isocyanate (TSI). TSI reacts with OH groups to produce a carbamate, a functional group that can be measured spectrally between ~1780 and 1690 cm−1 in the differential spectrum that is obtained from spectra collected before and after the reaction. Commercially available 1‐nonanol, which has a defined OHV, is used to develop a calibration. The OHV for a variety of 1° and 2° alcohols, as well as petrochemical and lipid‐based polyols, were then measured to evaluate the performance of the method and to assess the effects of moisture on the results. The FTIR OHV were in accord with the results obtained by AOCS method Cd 13‐60 and were demonstrated to be unaffected by the presence of moisture in the sample. The new TSI‐FTIR method is simpler, much faster (~10 min), and more reproducible and accurate than the AOCS OHV titrimetric methods and is not affected by carboxylic acids, amines or moisture.
Seed Oil Content and Fatty Acid Composition from Different Populations of Calotropis procera (Aiton) W. T. Aiton (Apocynaceae)
Authors: Barbosa Mariana Oliveira , de Almeida‐Cortez Jarcilene Silva , da Silva Suzene Izídio , de Oliveira Antonio Fernando Morais
Published: April 2014

Calotropis procera is a soft‐wooded, evergreen, perennial shrub species which grows in a variety of environments including dry habitats such as the Brazilian semi‐arid region. This study aimed to evaluate the variation in the oil content and fatty acid composition of C. procera seeds from four climatically different locations in the state of Pernambuco in the northeast of Brazil. The seed oil content of C. procera ranged from 19.7 to 24.0 %. Five main fatty acids were identified, with a predominance of unsaturated linoleic and oleic acids (approximately 70 %). Our results suggesting that environmental conditions influenced the seed oil biosynthesis of C. procera, because the localities with high temperature and low precipitation had increased oil content and total biosynthesis of saturated fatty acids. Multivariate analysis showed high similarity among three localities which share certain physiographic characteristics and climatic conditions such as temperature and precipitation values. The oil profile of C. procera presents interesting features that highlight its potential as a future alternative for the biodiesel market, especially in semi‐arid regions.
Nutritional improvement following growing rod surgery in children with early onset scoliosis
Authors: Myung Karen S. , Skaggs David L. , Thompson George H. , Emans John B. , Akbarnia Behrooz A. ,   Growing Spine Study Group
Published: April 2014

Purpose

We aimed to evaluate the nutritional status of children with early onset scoliosis (EOS) and to determine if treatment with growing rod instrumentation improves weight percentile.

Methods

Data was retrospectively collected on 88 EOS patients treated with growing rods at six institutions. Mean age at surgery was 5.8 years, and mean Cobb angle was 75°. All patients were followed for at least 2 years (mean 4 years). Weights were converted to normative percentiles based on the patients’ age and gender.

Results

Preoperatively, 47 % (41/88) of patients were <5 percentile for weight, thus failing to thrive. There was a significant increase in mean postoperative weight percentiles at latest follow-up ( p = 0.004). 49 % of patients gained weight, with a mean of 18 percentile. A significant relationship exists between age at initial surgery and percentile weight gain ( p < 0.005), with children <4 years old not demonstrating postoperative improvement. This relationship was not confounded by preoperative weight, preoperative Cobb angle, or years of follow-up ( p > 0.05). Children with neuromuscular and syndromic diagnoses do not appear to improve their mean nutritional status after surgery when compared to patients with idiopathic or congenital/structural scoliosis ( p = 0.006).

Conclusion

Following growing rod treatment, there was significant improvement in nutritional status in approximately 50 % of patients, similar to that reported with VEPTR. Neuromuscular and syndromic patients did not experience nutritional improvement post-operatively. These findings support the theory that growing rods improve the clinical status of EOS patients, as nutritional improvement is one outcome of improved clinical status. The relationship between age at initial surgery and nutritional improvement is intriguing.
Immunoglobulin G4‐related disease presenting with obstructive jaundice
Authors: Li Yuan‐Rung , Pan Chan‐Feng , Chan Hoi‐Hung , Lai Kowk‐Hung , Hsu Ping‐I
Published: April 2014

A 48‐year‐old male presented with diffuse abdominal fullness for 1 month and tea‐colored urine for 10 days. Abdominal computed tomography/magnetic resonance cholangiopancreatography revealed diffuse enlargement of the pancreas and unusual soft tissue density around the left ureter. Endoscopic retrograde cholangiopancreatography demonstrated lumen narrowing of the distal common bile duct and irregularity of the pancreatic duct. Markedly elevated serum immunoglobulin G4 (IgG4) was also noted. Biopsy of soft tissue from the area surrounding the left ureter identified lymphoplasmacytic infiltration with high concentrations of IgG4‐positive plasma cells accompanied by obliterative phlebitis, compatible with IgG4‐related disease. The patient was administered steroid therapy and his symptoms improved. Clinicians should be aware of possible IgG4‐related disease in a patient presenting with obstructive jaundice and diffuse pancreatic enlargement because glucocorticoid administration can achieve good response.
Analgesic effect of premedication with meperidine in patients undergoing colonoscopy without sedation
Authors: Tsai Ming‐Chang , Chen Tan‐Hsia , Lai Hsin‐Wu , Chen Tzy‐Yen , Chang Ming‐Huei , Lin Chun‐Che
Published: April 2014

Background

Colonoscopy is a standard and useful examination in the diagnosis of colorectal diseases; however, it usually causes pain to patients. Some patients receive narcotic drugs, e.g., meperidine, for pain relief if a colonoscopy is carried out without sedation. Whether the administration of such analgesic drugs to patients without sedation facilitates the performance of the colonoscopy or reduces pain remains to be elucidated. The aim of this study was to evaluate the analgesic effect of meperidine as premedication for patients undergoing a colonoscopy without sedation.

Patients and Methods

A total of 217 patients (109 men, 108 women) undergoing a diagnostic colonoscopy without sedation were analyzed prospectively. The procedures were carried out by three experienced endoscopists in a medical center. The patients could opt to receive analgesic drugs, with 25 mg of meperidine being given intramuscularly prior to the procedure if requested by either the doctor or patient. The colonoscopic examination was performed by one person using the short‐axis method. Questionnaires to evaluate abdominal pain during or after colonoscopy without sedation were collected and analyzed for patients who used meperidine as premedication (Group A) and for those who did not receive meperidine (Group B). Abdominal pain was evaluated using a visual analog scale from 0 to 10. The cecal intubation rate, total insertion time, and the patient's willingness to receive another colonoscopy in the future if needed were also analyzed.

Results

In both groups, the cecal intubation rate was more than 99% with no significant difference between groups. The mean ± standard deviation insertion time was 7.14 ± 5.45 minutes in Group A and 6.24 ± 4.24 minutes in Group B (p = 0.309). The visual analog pain score was 3.54 ± 3.13 in Group A and 2.46 ± 2.75 in Group B (p = 0.009). After adjusting for age and sex, the pain score was 3.51 ± 3.21 in Group A (p = 0.055). Multivariate analysis showed that female sex and the individual endoscopist performing the colonoscopy were associated with abdominal pain during the examination.

Conclusion

In our study, premedication with meperidine or no premedication was not associated with a reduction in abdominal pain during colonoscopy without sedation. The insertion time and cecal intubation rate showed no difference between patients with or without additional analgesic drugs prior to the procedure. However, as self‐selection bias could not be ruled out, further randomized, placebo‐controlled trials are needed to confirm our findings.
Missing Data: The Importance and Impact of Missing Data from Clinical Research
Authors: Padgett Christine R. , Skilbeck Clive E. , Summers Mathew James
Published: April 2014

There is compelling evidence that traditional methods used to address the detrimental impacts of missing data are inadequate. Despite this, researchers have been slow to utilise newer statistical approaches known to be more effective. The aim of the current article is to offer a conceptual explanation of the rationale for using newer missing data techniques, with a focus on multiple imputation (MI). To illustrate the relative efficacy of deletion, single imputation and multiple imputation techniques in the clinical setting, 20 cases were selected randomly from a population study investigating the cognitive sequelae of traumatic brain injury (TBI), and 8 out of 20 cases had scores on one variable deleted to simulate a missing data set. Comparing the parameter estimates obtained by each technique to the known parameters of the complete data set revealed that MI outperformed deletion and single imputation approaches. It is therefore recommended that more sophisticated techniques such as MI should be considered in clinical research.
Preparations for Severe Winter Conditions by Emergency Health Personnel in Turkey
Authors: Çalışkan Cüneyt , Algan Aysun , Koçak Hüseyin , Biçer Burcu Küçük , Şengelen Meltem , Çakir Banu
Published: April 2014

Objective

Emergency and core ambulance personnel work under all environmental conditions, including severe weather condtions. We evaluated emergency medical personnel in Çanakkale, Turkey, for their degree of preparedness.

Methods

A descriptive study was conducted in Çanakkale, Turkey, within 112 emergency service units and their 17 district stations. Surveys were developed to measure the level of preparedness for serious winter conditions that individual workers made for themselves, their homes, and their cars.

Results

Of the 167 survey participants, the mean age was 29.8 ± 7.9 years; 52.7% were women; more than half (54.75%) were emergency medical technicians; and 53.3% were married. Only 10.4% of those who heated their homes with natural gas had carbon monoxide detectors. Scores relating to household and individual preparation for severe winter conditions increased by participants’ age (P < .003), being married (P < .000) and working in the city center (P < .021); and for men whose cars were equipped with tow ropes, extra clothing, and snow tires (P < .05). Absenteeism was higher for central-city personnel than district workers because they were less prepared for harsh winter conditions (P = .016).

Conclusion

Many of the surveyed emergency health personel demonstrated insufficient preparations for serious winter conditions. To increase the safety and efficiency of emergency medical personnel, educational training programs should be rountinely conducted. (Disaster Med Public Health Preparedness. 2014;0:1-4)