bluuebunny/crossref_metadata_2025_split huggingface dataset:
Highly compact UWB printed monopole antennas with different ground plane structures
Authors: Thwin Su Sandar 
Published: March 2013

AbstractThis article presents highly compact‐sized, low‐profile, and planar monopole antennas for ultra‐wideband (UWB) operations.The two proposed antennas' structures consist of the circular radiating patch with microstrip‐fed monopole structure and coplanar waveguide‐fed (CPW) monopole structure. By properly selecting positions and dimensions of the embedded slots in the radiating patch and ground planes, wide impedance bandwidths are achieved. The numerical and experimental results show that the designed antennas can operate over UWB band groups 2, 3, 4, and 5 and satellite communications. The designed antennas have the simple uniplanar structures and occupy small size of 11 × 16 mm2 including the finite ground CPW feeding mechanism and partial ground microstrip line feeding mechanism. In addition, acceptable radiation characteristics are obtained over the operating bands. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1191–1196, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27538
An efficient de‐embedding technique for evaluating the S‐parameters of microwave circuits and printed antennas
Authors: Bianconi Giacomo , Pelletti Chiara , Mittra Raj 
Published: March 2013

AbstractIn this article, we present an efficient de‐embedding technique based on the characteristic basis function method for an accurate evaluation of the “generalized S‐parameters” for microstrip circuits and antennas etched on layered media. Numerical examples are provided to demonstrate the reliability and computational efficiency of the described procedure. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1266–1270, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27549
Bidirectional rectangular ring antenna for coal mine/tunnel communication
Authors: Liu Wendong , Zhang Zhijun , Feng Zhenghe 
Published: March 2013

AbstractA bidirectional antenna, which is useful in coal mine or tunnel wireless communication, is proposed in this article. The antenna consists of a probe excited rectangular ring. The dimensions of the rectangular ring are 147 × 20 × 40 mm3 (0.45λ × 0.06λ × 0.12λ). The length of the feeding probe is 15 mm (0.045λ). The measured −10 dB bandwidth is ∼14 MHz (910–924 MHz), and the corresponding peak gain is 5.8 dBi. Radiation patterns are measured and compared to the simulation results. The proposed bidirectional antenna has the advantages of low cost, low‐profile, easy fabrication, small cross‐section to the ventilation direction, and good bidirectional radiation. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1412–1416, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27552
Electrically coupled loop antenna as a dual for the planar inverted‐f antenna
Authors: Manteghi Majid 
Published: March 2013

AbstractThe electrically coupled loop antenna is presented as a dual for the existing planar inverted F antenna (PIFA).The basic drawbacks of the PIFA are low radiation efficiency and high electric field in the near zone. The dual antenna has high radiation efficiency and low electric field in the near zone that makes it a good candidate for cellphones and implanted antenna applications. The antenna is designed and simulated using HFSS and the results are compared with the measured data. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1409–1412, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27553
A novel printed microstrip antenna with frequency reconfigurable characteristics for bluetooth/WLAN/WIMAX applications
Authors: Pan Yong , Liu Kaihua , Hou Ziye 
Published: March 2013

AbstractA novel printed microstrip reconfigurable antenna with three switchable frequencies is proposed. The proposed microstrip‐fed antenna was fabricated on FR4 substrate and mainly consists of four semicircular rings, one circular ring, one cross strip, and one defected ground plane. The uniqueness of this design is that various groups of operating frequencies can be selected electronically by controlling two PIN diode switches purposefully. Several kinds of reconfigurable resonant frequencies covering the bands of 2.30–2.53 GHz, 3.19–3.81 GHz, and 4.68–6.03 GHz, which can be applied in the systems of Bluetooth (2.4–2.484 GHz), WiMAX (3.3–3.6 GHz), and WLAN (2.4–2.484 GHz, 5.15–5.35 GHz, and 5.725–5.875 GHz), are achieved. Meanwhile, the presented antenna has nearly omnidirectional radiation patterns and relatively high gains. By comparing the simulated and measured results, a good agreement is obtained. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1341–1345, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27556
A modified balanced antipodal vivaldi antenna with improved radiation characteristics
Authors: Juan Lei , Guang Fu , Lin Yang , Demin Fu 
Published: March 2013

AbstractA modified corrugated balanced antipodal Vivaldi antenna with director (CBAVA‐D) is presented for ultrawideband (UWB) applications in this article. The main features of the antenna, besides an UWB width are high gain, low cross‐polarization, and excellent group delay. The new antenna concept, including the hybrid structure of exponential tapered corrugation edge and curving dielectric director with high‐dielectric constant is demonstrated, based on simulation and measurement results in both frequency and time domain. The antenna prototype input match is better than −10 dB, the maximal gain of 12.6 dB and the cross‐polarization level less than −30 dB in the main beam direction at 1.5–15 GHz band are achieved. In the time domain measured group delay with variation less than ±0.25 ns in the whole operating band is also obtained and exhibited. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1321–1325, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27558
Broad band microstrip antenna with 100 μM slits on elevated edges for C‐ and X‐band communication
Authors: Bordoloi Anup Kr. , Borah Pranjal , Bhattacharyya Satyajib , Bhattacharyya Nidhi S. 
Published: March 2013

AbstractIn the present work, a rectangular microstrip patch antenna having 100 μm slits on the conductor parellel to and 2.5 mm from the radiating edges on both sides is designed.The conductor sections from the slits to the outer edges are elevated at an angle from the conductorplane. Prominent return loss peaks are obtained at 4.23 GHz and 10.26 GHz with return losses of −36 dB and −32 dB, respectively. A large frequency envelope with at least −10 dB return loss in the range 6.84 GHz to 9.24 GHz for elevation angle 65° and 8.45 GHz to 10.54 GHz for elevation angle 85° are obtained. The frequencies can be varied by changing the elevation angles. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1285–1287, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27560
Miniaturized quasi‐lumped coupled‐line single‐section directional coupler designed in multilayer LTCC technology
Authors: Piekarz Ilona , Sorocki Jakub , Wincza Krzysztof , Gruszczynski Slawomir , Muller Jens , Welker Tilo 
Published: March 2013

AbstractThe design of a miniaturized broadband directional coupler realized with the use of a quasi‐lumped element approach has been presented.The designed coupler takes advantage of Low Temperature Co‐fired Ceramics (LTCC) technology, in which miniaturized coupled inductors are realized with the use of a multilayer stacked structure being vital in terms of possible miniaturization of the circuit. It has been shown that the mutual coupling between consecutive turns of the spiral coupled inductors deteriorate the coupler's performance which can be improved when appropriate mutual and shunt capacitances are added. The theoretical analysis as well as measurements of a 3‐dB directional coupler operating at f0 = 1.5 GHz have been presented. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1401–1405, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27582
A low‐profile dual‐layer ultra‐wideband frequency selective surface reflector
Authors: Ranga Yogesh , Matekovits Ladislau , Weily Andrew R. , Esselle Karu P. 
Published: March 2013

AbstractAn ultra‐wideband (UWB), dual‐layer frequency selective surface (FSS) is presented.This compact low‐profile FSS has been designed as a reflector for UWB antennas. It can be inserted between a planar UWB antenna and a nearby parallel conducting surface such as a circuit board, screen, or a metal case, to isolate them and to prevent antenna impedance mismatch otherwise caused by the conductor. The measured transmission coefficient magnitude of the FSS is less than −10 dB over a 133% bandwidth and its reflection phase is appropriate for this and other similar reflector applications, over an UWB. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1223–1227, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27583
An efficient, broad bandwidth, high directivity, electrically small antenna
Authors: Ziolkowski Richard W. , Tang Ming‐Chun , Zhu Ning 
Published: March 2013

AbstractFundamental physics limits the performance characteristics of passive electrically small antennas. A 300 MHz design, which includes non‐Foster elements and exceeds those limits, is reported. It simultaneously achieves high radiation efficiencies (>81.63%), high directivities (>6.25 dB), and large front‐to‐back‐ratios (>26.71 dB) over a 10.0% fractional bandwidth. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1430–1434, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27587
Low power, high gain, low noise amplifier (LNA) for ultra wide‐band applications
Authors: Iji Ayobami , Zhu Xie , Heimlich Michael 
Published: March 2013

AbstractOne of the important components of a receiver is the low noise amplifier (LNA). The challenges of LNA design include ability to achieve high gain, low noise figure, and better linearity at low power consumption within the required frequency. In this article, our design is based on Impulse Response (IR) Ultra Wide‐Band (UWB) transceiver operating at 3.1–4.6 GHz. Hence, the LNA designed has been optimized for low noise figure, considerably high gain and better linearity at low power consumption, which make it suitable for implantable radio application. The process technology used here is 0.25 μm CMOS Silanna process. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1399–1401, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27588
High isolation tri‐band BPF using tri‐mode resonator
Authors: Chen Hui 
Published: March 2013

AbstractA compact tri‐band bandpass filter (BPF) with high isolation and selectivity is proposed in this article, which is based on a tri‐mode rectangular open‐loop resonator (ROLR) loaded by an open‐circuited stub. Characterized by both theoretical analysis and full‐wave EM simulation, the proposed resonator is found to have the advantage that the first‐ and third‐mode resonant frequencies can be flexibly controlled by the length of the open‐circuited stub, whereas the second‐mode resonant frequency is mainly determined by the length of the ROLR. With the multipath propagation mode configuration of the two resonators, the transmission zeros among each passband are generated to improve passband selectivity and achieve high isolation. Theoretical prediction is verified by the experimental result of the proposed tri‐band BPF. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1367–1370, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27596
Natural course of muscular involvement assessed by a new computed tomography method in Duchenne muscular dystrophy
Authors: Kuru Satoshi , Sakai Motoko , Tanaka Nobuhiko , Konagaya Masaaki , Nakayam Takahiro , Kawai Mitsuru 
Published: March 2013

AbstractAimEstablishing the natural course of muscular impairment in Duchenne muscular dystrophy (DMD) is essential for defining the effect of treatments in clinical trials. We retrospectively investigated the change of thigh muscle volume in DMD using new indices, muscle volume index (MVI) and %MVI.MethodsMVI is the estimated muscle volume contained within a given computed tomography (CT) slice and calculated using the CT histogram‐based procedure after correcting for a partial volume effect. %MVI is calculated by dividing the MVI by the entire volume of the region of interest. We applied this method to 49 retrospectively selected CT images from 21 patients with DMD, aged 6–13 years, at a relatively early stage.ResultsBoth MVI and %MVI were found to have a significant inverse correlation with the clinical disability stage. In most patients, the changes over time in MVI and %MVI could be regressed to the exponential function Y = Ae−rX. The rate constant of the approximation curve was 0.299 ± 0.072 for MVI, and 0.351 ± 0.088 for %MVI, respectively.ConclusionMVI and %MVI have proven useful for follow‐up assessments of skeletal muscle volume in patients with DMD. Our retrospective longitudinal study should provide a basis for evaluating therapeutic interventions in future clinical trials.
Serum adiponectin levels are associated with hepatitis B viral load in overweight to obese hepatitis B virus carriers
Authors: Chiang Chien‐Hsieh , Lai Jin‐Shin , Hung Shou‐Hung , Lee Long‐Teng , Sheu Jin‐Chuan , Huang Kuo‐Chin 
Published: March 2013

AbstractObjective:This study aimed to investigate the association between serum adiponectin and chronic hepatitis B virus (HBV) infection.Design and Methods:We conducted a campus‐based cross‐sectional study in Northern Taiwan, an HBV‐endemic country. A total of 506 participants, including 147 chronic HBV‐infected individuals and 359 healthy controls, were assessed for anthropometric indices, serum adiponectin levels, serum HBV viral load and markers, serum alanine aminotransferase levels and metabolic factors.Results:Older age, male gender, higher alanine aminotransferase, higher body mass index, greater waist circumference, lower fasting glucose, higher triglycerides, and higher adiponectin were associated with chronic HBV infection in univariate analyses. In multivariate analysis, the presence of chronic HBV infection was positively associated with serum adiponectin levels (P < 0.0001) and high adiponectin levels over the 75th percentile (odds ratio, 4.25; 95% confidence interval, 2.36‐7.66; P < 0.0001) after adjusting for age, gender, body mass index, and insulin resistance index. Furthermore, serum adiponectin levels were positively associated with HBV viral load in overweight to obese HBV‐infected subjects (P = 0.018).Conclusion:Although chronic HBV‐infected individuals were heavier than healthy controls, they had significantly higher serum adiponectin levels than healthy counterparts. Additionally, adiponectin levels were positively associated with HBV viral load in overweight to obese HBV‐infected subjects. Future research should focus on elucidating adiponectin pathways, which may contribute to the development of adjuvant treatments for chronic HBV infection.
Gastric emptying and Ca2+ and K+ channels of circular smooth muscle cells in diet‐induced obese prone and resistant rats
Authors: Li Shiying , Maude‐Griffin Roland , Pullan Andrew J. , Chen Jiande D Z 
Published: March 2013

AbstractObjective:Accelerated gastric emptying that precipitates hunger and frequent eating could be a potential factor in the development of obesity. The aim of this study was to study gastric emptying in diet‐induced obese‐prone (DIO‐P) and DIO‐resistant (DIO‐R) rats and explore possible differences in electrical properties of calcium (Ca2+) and potassium (K+) channels of antral circular smooth muscle cells (SMCs).Design and Methods:Whole‐cell patch‐clamp technique was used to measure Ca2+ and K+ currents in single SMCs. Gastric emptying was evaluated 90 min after the ingestion of a solid meal.Results:Solid gastric emptying in the DIO‐P rats was significantly faster compared with that in the DIO‐R rats. The peak amplitude of L‐type Ca2+ current (IBa,L) at 10 mV in DIO‐P rats was greater than that in DIO‐R rats without alternation of the current–voltage curve and voltage‐dependent activation and inactivation. The half‐maximal inactivation voltage of transient outward K+ current (IKto) was more depolarized (∼4 mV) in DIO‐P rats compared with that in DIO‐R rats. No difference was found in the current density or recovery kinetics of IKto between two groups. The current density of delayed rectifier K+ current (IKdr), which was sensitive to tetraethylammonium chloride but not 4‐aminopyridine, was lower in DIO‐P rats than that in DIO‐R rats.Conclusion:The accelerated gastric emptying in DIO‐P rats might be attributed to a higher density of IBa,L, depolarizing shift of inactivation curve of IKto and lower density of IKdr observed in the antral SMCs of DIO‐P rats.
Obesity and early mortality in the United States
Authors: Greenberg James A. 
Published: March 2013

AbstractObjective:Although obesity is a serious public health problem, there are few reliable measures of its health hazards in the United States. The objective of this study was to estimate how much earlier mortality is likely to occur for Americans who are obese (body mass index [BMI], ≥ 30).Design and Methods:Data from the National Health and Nutrition Examination Survey (NHANES) I (1971–1975), NHANES II (1976–1980), and NHANES III (1988–1994) for 37,632 participants who experienced 8,791 deaths during 15 years of follow‐up were prospectively analyzed. The relative risk of death from all causes and its advancement period, adjusted for covariates, were calculated. Stratification was used to investigate the effects of pre‐existing illness, smoking, and older age on the advancement period.Results:Compared to the participants of reference weight (BMI, 23 to <25 kg/m2), mortality was likely to occur 9.44 years (95% confidence interval [CI]: 0.72, 18.16) earlier for those who were obese (BMI, ≥ 30). For overweight (25 to <30 kg/m2), grade 1 obesity (BMI, 30 to <35) and grades 2–3 obesity (BMI, ≥ 35.0), the mortality was likely to occur earlier by 4.40 (−3.90, 12.70), 6.69 (−2.06, 15.43), and 14.16 (3.35, 24.97) years, respectively. These estimates apply to healthy nonsmoker young‐ and middle‐aged (21–55 years) adults, who constituted an estimated 32.8% of Americans with age of >21 years between 1988 and 1994. Without stratifying simultaneously for preexisting illness, smoking, and age, values of the advancement period for obesity were markedly smaller than those observed for healthy nonsmoker young and middle‐aged adults.Conclusions:For healthy nonsmokers young‐ and middle‐aged adults who constitute about one‐third of American adults, being obese is likely to hasten mortality by 9.44 years.
Adaptive thermogenesis with weight loss in humans
Authors: Müller M.J. , Bosy‐Westphal A. 
Published: March 2013

AbstractAdaptive thermogenesis (AT) with weight loss refers to underfeeding‐associated fall in resting and non‐resting energy expenditure (REE, non‐REE); this is independent of body weight and body composition. In humans, the existence of AT was inconsistently shown and its clinical significance has been questioned.Objectives:Discrepant findings are mainly due to different definitions of AT, the use of various and nonstandardized study protocols, and the limits of accuracy of methods to assess energy expenditure. With controlled underfeeding, AT takes more than 2 wk to develop. AT accounts to an average of 0.5 MJ (or 120 kcal) with a considerable between subject variance.Design and Methods:Low‐sympathetic nervous system activity, 3,5,3′‐tri‐iodothyronine (T3) and leptin are likely to add to AT; however, the kinetic changes of their plasma levels with underfeeding differ from the time course of AT and controlled intervention studies substituting and titrating these hormones are rare in humans. AT in response to underfeeding is independent of thermogenesis in response to either diet or cold. Although fat‐free mass (FFM) and, thus, liver, and skeletal muscle are considered as major sites of AT, cold‐induced nonshivering thermogenesis relates to the metabolism of brown adipose tissue (BAT). In humans, diet‐induced thermogenesis is related to postprandial substrate metabolism of FFM with a questionable role of BAT. Obviously, the REE component of AT differs from and its non‐REE component with respect to organ contribution as well as mechanisms. Thus, AT cannot be considered as unique.Conclusions:AT should be characterized based on individual components of daily energy expenditure, detailed body composition analyses, and mathematical modeling. The biological basis of AT as well as the influences of age, sex, obesity, stress, and inflammation remain to be established in humans.
Effects of increased meal frequency on fat oxidation and perceived hunger
Authors: Ohkawara Kazunori , Cornier Marc‐Andre , Kohrt Wendy M. , Melanson Edward L 
Published: March 2013

AbstractObjective:Consuming smaller, more frequent meals is often advocated as a means of controlling body weight, but studies demonstrating a mechanistic effect of this practice on factors associated with body weight regulation are lacking. The purpose of this study was to compare the effect of consuming three (3M) vs. six meals (6M) per day on 24‐h fat oxidation and subjective ratings of hunger.Design and Methods:Lean (body mass index <25 kg/m2) subjects (7M, 8F) were studied in a whole‐room calorimeter on two occasions in a randomized cross‐over design. Subjects were provided isoenergetic, energy balanced diets with a 1‐ to 2‐week washout between conditions. Hunger, fullness, and “desire to eat” ratings were assessed throughout the day using visual analog scales and quantified as area under the curve (AUC).Results:There were no differences (P < 0.05) in 24‐h energy expenditure (8.7 ± 0.3 vs. 8.6 ± 0.3 mj d−1), 24‐h respiratory quotient (0.85 ± 0.01 vs. 0.85 ± 0.01), or 24‐h fat oxidation (82 ± 6 vs. 80 ± 7 g day‐1) between 3M and 6M, respectively. There was no difference in fullness 24‐h AUC, but hunger AUC (41850 ± 2255 vs. 36612 ± 2556 mm.24 h, P = 0.03) and “desire to eat” AUC (47061 ± 1791 vs. 41170 ± 2574 mm.24 h, P = 0.03) were greater during 6M than 3M.Conclusion:We conclude that increasing meal frequency from three to six per day has no significant effect on 24‐h fat oxidation, but may increase hunger and the desire to eat.
High and low activity rats: Elevated intrinsic physical activity drives resistance to diet‐induced obesity in non‐bred rats
Authors: Perez‐Leighton Claudio E. , Boland Kelsey , Billington Charles J. , Kotz Catherine M. 
Published: March 2013

AbstractObjective:Humans and rodents show large variability in their individual sensitivity to diet‐induced obesity (DIO), which has been associated with differences in intrinsic spontaneous physical activity (SPA). Evidence from genetic and out‐bred rat obesity models shows that higher activity of the orexin peptides results in higher intrinsic SPA and protection against DIO. Based on this, we hypothesized that naturally occurring variation in SPA and orexin signaling is sufficient to drive differences in sensitivity to DIO.Design and Methods:Orexin expression, behavioral responses to orexin‐A, basal energy expenditure and sensitivity to DIO were measured in in non‐manipulated male Sprague‐Dawley rats selected for high and low intrinsic SPA.Results:Male Sprague‐Dawley rats were classified as high‐activity or low‐activity based on differences in intrinsic SPA. High‐activity rats showed higher expression of prepro‐orexin mRNA, higher sensitivity to behavioral effects of orexin injection, higher basal energy expenditure and were more resistant to obesity caused by high‐fat diet consumption than low‐activity rats.Conclusion:Our results define a new model of differential DIO sensitivity, the high‐activity and low‐activity rats, and suggest that naturally occurring variations in intrinsic SPA cause differences in energy expenditure that are mediated by orexin signaling and alter DIO sensitivity.