bluuebunny/crossref_metadata_2025 huggingface dataset:
Erratum: Solution of electromagnetic scattering problems by transformation into high‐order impedance boundary condition
Authors: Tezel Necmi Serkan
Published: July 2009

Originally published Microwave Opt Technol Lett 50: 832–836, 2008. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2525, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24590
Erratum: Bow‐tie antenna using high‐impedance ground plane
Authors: Lee Yi‐Chieh , Sun Jwo‐Shiun
Published: July 2009

Originally published Microwave Opt Technol Lett 50: 2928–2931, 2008. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2525, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24591
On‐body radio channel modeling for different human body models using FDTD techniques
Authors: Terchoune Hanae , Lautru David , Gati Azeddine , Carrasco Albert Cortel , Wong Man Faï , Wiart Joe , Hanna Victor Fouad
Published: July 2009

This articlepresents an on‐body radio channel modeling at 900MHz using the FDTD technique. The modification of antennas parameters when they are close to the body or directly on the body is analyzed. Then, the influence of the morphology on the propagation is studied; SAR and channel parameters are also extracted. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2498–2501, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24592
A composite antenna with wide circularly polarized beamwidth
Authors: Shi Lei , Sun Houjun , Lu Xin
Published: July 2009

A circularly polarized (CP) composite antenna is studied in this article. The antenna unit is composed of a CP curl antenna and a CP omni‐directional antenna with three pairs of tilted parasitic elements. Reasonable agreement between simulation and measurement is obtained. The proposed antenna has a 10‐dB impedance bandwidth (S11 < −10 dB) of 35% and a 3‐dB axial ratio (AR) bandwidth of 20%. The composite antenna and the reference antenna are compared in this article. The composite antenna can obtain a 3‐dB power gain beamwidth of 110° and 3‐dB AR beamwidth of 120°, when compared with those of the reference antenna with 95° and 95°, respectively. The characteristics of the composite antenna are also investigated. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2461–2464, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24594
Microstrip bandpass filter design using triangular open loop resonators with improved cross‐coupled structure
Authors: Liu Haiwen , Tan Mingtao
Published: July 2009

In this letter, a highly selective microstrip bandpass filter using triangular open‐loop resonators with improved cross‐coupled structure is designed, fabricated, and measured. The new cross coupling structure is implemented by inserting two L‐shaped stubs into the triangular open‐loop resonators. A good agreement is achieved between simulated and measured results. Measurements are given to verify that a passband from 5.1 to 5.5 GHz with the insertion loss less than 1.0 dB and return loss more than 20 dB is obtained. There are two transmission zeros on both sides of the passband which lead to higher selectivity for the passband. In addition, two extra transmission zeros are observed obviously and located at about 7.0 GHz and 9.0 GHz, respectively, for high out‐of‐band rejection. The filter has a compact size of 10 mm × 6 mm which amounts to about 0.3 λg × 0.2 λg. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2346–2348, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24599
Study of the passive microwave RFID tag range using distance‐dependent reflection coefficient over multipath channel
Authors: Wei Fu , Jianguo Ma
Published: July 2009

The distance‐dependent reflection coefficients are investigated based on a multi‐ray model at microwave frequency bands. Tag range of passive microwave radio‐frequency identification (RFID) systems is then calculated taking into account the tagged object material characteristic. Obtained values are verified through the precise simulations based on a 3‐D physical finite element model. The results shown that the proposed method provides a good agreement than that obtained by existing methods. The analytical method can be used for the empirical tag range value to avoid reader collision while ensuring system reliability. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2266–2268, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24602
A novel miniaturized frequency selective surface with excellent center frequency stability
Authors: Yang Hong‐Yu , Gong Shu‐Xi , Zhang Peng‐Fei , Zha Feng‐Tao , Ling Jin
Published: July 2009

A novel miniaturized frequency selective surface is proposed. The size reduction is achieved by bending the edge of square loop aperture into the inner space to lengthen the resonant length. Compared with conventional square loop aperture frequency selective surface (FSS), the area of this miniaturized‐element is reduced by 78% at the same operation frequency of 2.9 GHz. Both theoretical and experimental investigations are carried out. It is observed that the miniaturized FSS presents excellent center frequency stability with the increase of the incident angle. This proposed FSS can be a good candidate for FSS radomes which present large incident angle to the coming wave. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2513–2516, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24604
A three‐in‐one diversity antenna system for 5 GHz WLAN applications
Authors: Su Saou‐Wen
Published: July 2009

A novel, three‐in‐one antenna system suitable for WLAN operation in the 5 GHz band is presented. The design is based upon incorporating one slot and two dipole antennas into a compact multiantenna system that has comparable dimensions of a single mobile‐unit antenna element. The three antennas are arranged parallel to each other with the two dipoles set on the right and left sides of the slot respectively. With this arrangement, not only can compact integration of three individual antennas be realized, pattern diversity and polarization diversity are also obtained. A design prototype has been constructed and tested. The results show that the coupling or the antenna port isolation is below −20 dB and good radiation characteristics have been observed. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2477–2481, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24606
Frequency response of fiber ring resonator and its application in DFB laser wavelength variation measurement
Authors: Chen Wei , Zhu Ning Hua , Ren Min , Xie Liang
Published: July 2009

Frequency response of a fiber ring resonator (FRR) composed of an ordinary optical coupler and a segment of optical fiber is theoretically and experimentally investigated. The frequency response equation based on small‐signal modulation is derived and studied in detail. It is shown that the shape of the frequency response curve is very sensitive to the wavelength; as a result, the FRR can be applied to measure the wavelength of a lightwave source with high resolution. With this method, we demonstrate the measurement of tiny changes of wavelength of a DFB laser. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2444–2448, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24608
Hetero junction bipolar transistor‐based cascode amplifier with high‐frequency loss compensation network
Authors: Wang Rong , Gao Huai , Chatchaikarn Aroonchat , Li G. P.
Published: July 2009

Performance analysis and design methodology of an HBT cascode amplifier with series RLC loss compensation network are reported in this article. The series RLC loss compensation network enhances the gain‐bandwidth product of the cascode amplifier. For comparison, cascode amplifiers with and without RLC loss compensation network are designed and fabricated on 2 μm InGaP/GaAs HBT technology. The measurement results show that the gain‐bandwidth product for the amplifier with loss compensation network is increased by a factor of 4, compared with the conventional amplifier. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2410–2413, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24611
Analysis and design of stub bandpass filters using tapped‐line geometry
Authors: Yun Tae‐Soon , Yoon Yong‐Kyu , Lee Byungje , Choi Jin‐Joo , Kim Jin‐Young , Lee Jong‐Chul
Published: July 2009

A simplified mathematical design method for tapped‐line geometry is presented and the stub bandpass filters (BPFs) of λg/4 and λg/2 stubs with a center frequency of 5.8 GHz and a bandwidth of 5% are successfully designed, fabricated, and characterized using this approach. Design parameters for the tapped‐line geometry of the filter prototypes are obtained using input (output) admittance toward source (load), where the open‐stub and the additional transmission‐line with a negative electrical length are taken into account for filter implementation. The electrical lengths of the stubs and lines are functions of the line admittance and J‐inverter. The filters are implemented on a RT‐duroid substrate and the results from modeling and measurement show good agreement with each other. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2338–2341, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24615
Second‐order statistics of measured on‐body diversity channels
Authors: Khan Imdad , Nechayev Y. I. , Hall Peter S.
Published: July 2009

The fading severity, and the improvement offered by diversity to reduce it, is presented in the context of the second‐order statistics for on‐body belt‐head channel. Average LCR and AFD values are presented and compared at three frequencies and also for the three antennas for branch and combined signals. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2335–2337, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24621
A compact rectangular dielectric resonator antenna for UWB wireless communication systems
Authors: Aoutoul Mohssin , El‐Mrabet Otman , Essaaidi Mohamed , El Moussaoui Ahmed
Published: July 2009

A compact rectangular dielectric resonator antenna (DRA) is presented for ultra wide band communication systems. Ansoft HFSS 3D electromagnetic solver is used for the design optimization and measurement results are also provided. The proposed antenna has a low profile (∼3), a small size, and a low permittivity constant (10.2). An impedance bandwidth about 46% (from 6.9 to 11 GHz) was achieved making this antenna suitable for UWB applications. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2281–2286, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24623
Erratum: Engineering the phase speed of surface plasmon wave at the planar interface of a metal and a chiral sculptured thin film
Authors: Lakhtakia Akhlesh , Polo John A.
Published: July 2009

Originally published Microwave Opt Technol Lett 50:1966–1970, 2008. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2524, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24663
Design of a quad‐band antenna for wireless communication
Authors: Hong Seokjin , Chung Kyungho , Kim Jeongpyo , Choi Jaehoon
Published: July 2009

A multiband slot antenna with two parasitic radiators for GSM900/DCS1900/WiMAX/WLAN wireless communication services is introduced. The proposed antenna is small in size (40 mm × 40 mm × 1.6 mm) and has a simple structure. The bandwidth and resonant frequencies of the antenna are controlled by the electromagnetic coupling among radiators. Details of the antenna design are described and the effects of design parameters on antenna performance are investigated. The experimental results of the constructed prototype are presented and discussed. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2277–2281, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24634
Compact tapped stepped impedance open stub dual‐band bandstop filters with sharp rejection characteristics
Authors: Velidi Vamsi Krishna , Guntupalli Ajaybabu , Sanyal Subrata
Published: July 2009

In this article, a novel transmission line (TL) shunt stepped impedance open stub configuration has been presented to design a dual‐band bandstop filter with impedance controlled center frequencies and bandwidths. Design guidelines are derived using lossless TL model. The high‐impedance lines required for TL sections facilitate convenient meandering that makes the geometry compact. To validate theoretical predictions, a prototype filter operating at two bands 1.5 and 3.4 GHz has been fabricated. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2274–2277, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24635
A wideband circular polarization antenna for portable INMARSAT BGAN terminal applications
Authors: Fu Shi‐Qiang , Fang Shao‐Jun , Wang Zhong‐Bao , Li Xiao‐Ming
Published: July 2009

A low profile, wideband, and portable antenna has been designed and fabricated for Inmarsat broadband global area network (BGAN) land mobile terminal applications. The purpose of the antenna was to provide a low‐cost and easy‐fabricated solution with wide bandwidth and high performance. The proposed antenna is composed of the stacked corner‐truncated patches with sequential rotation oblique feed and a serial feeding network. Good antenna characteristics are achieved over the BGAN operating bands. The measurement results for return loss, gain, axial ratio, and radiation pattern confirm the integrity of the simulation results. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2354–2357, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24643
Novel ultra wideband filter using three coupled lines and short stubs
Authors: Li Qi , Liang Chang‐Hong , Lai Xin , Chen Jian‐Zhong
Published: July 2009

A novel compact ultra‐wideband bandpass filter is proposed to meet Federal Communications Commission's spectrum mask. Shunt short‐circuited stubs and the parallel coupled lines are used to achieve a fraction passband from 3.1 GHz to 10.6 GHz. Three interdigital edge coupled microstrip lines are used for coupling enhancement. By employing short‐circuited stubs, this filter significantly improves the selectivity and out‐of‐band characteristics. For verification, the proposed filter is designed, simulated, and fabricated with good agreement. The design of the filter is simple, and it shows good frequency response. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2272–2274, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24646
Log periodic bandstop filter
Authors: Sithole E. S. , Malherbe J. A. G.
Published: July 2009

Most conventional transmission line filters are commensurate structures, with all elements that contribute to the filter performance of equal length. In this article, a structure is described that makes use of a series of elements that vary in length and spacing according to a logarithmic function; this results in a series of transmission zeros at real frequencies. It is shown that excellent filtering performance can be obtained from a relatively simple construction. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2418–2420, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24652
Broadband E‐shaped monopole antenna for USB dongle application
Authors: Jung Jinwoo , Lee Hyeonjin , Lim Yeongseog
Published: July 2009

A broadband E‐shaped monopole antenna for universal serial bus (USB) dongle applications is demonstrated experimentally and numerically. According to the experimental results, the operating mode has an impedance bandwidth of approximately 39.8% (1.83–2.74 GHz) that covers the UMTS, WiBro, WLAN, and S‐DMB bands, and omnidirectional radiation patterns were obtained. It is suitable for application to a USB dongle with its relatively low profile. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2387–2390, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24654
A transmit/receive twin‐horn feed for spinning remote sensing reflector antennas
Authors: Xu Shenheng , Farhad Razavi S. , Rahmat‐Samii Yahya
Published: July 2009

A gravitationally balanced reflector antenna with minimized spun inertia has recently been considered for remote sensing applications. The back‐to‐back reflector antenna structure is used to generate two off‐nadir scanned beams. In particular, to overcome the large azimuth displacement between Tx/Rx events due to the high spinning rate and high orbit altitude of the antenna, a customized integrated twin‐horn feed with partially overlapped corrugation is designed to transmit and receive signals, respectively. Simulation and measurement results of the twin‐horn feed agree very well. The simulated far‐field pattern of the reflector antenna matches well with the design goals. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2505–2510, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24656
Measurement of electric power using an optical fiber grating
Authors: Cheng Chin‐Hsing , Lin Li‐Min , Liu Wen‐Fung
Published: July 2009

There is increasing motivation to develop sensors and actuators to manage domestic electric power consumption. This article demonstrates an optical fiber sensor using a superstructure fiber grating (SFG) to measure electric power consumption. The sensor head is based on SFG encapsulated in a polymer‐half‐field metal cylinder embedded a magnetic material at measure point. The operating mechanism is that the sensor can be attracted by the induced magnetic force created by the electric power in the solenoid along one radial direction only, and responds to an axial force on the magnetic rod attached to the round plate, creating an axial attraction on the SFG. Therefore, variations in attractive force cause center‐wavelength variations in SFB and long‐period grating acts as an edge filter converting strain‐induced wavelength variation into optical power measurement. Thus, the sensor can be used to measure electric power without the use of power meter. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2438–2441, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24660
Microwave conductivity measurements of carbon veil by two different methods
Authors: Karimkashi Shaya , Kajfez Darko , Kishk Ahmed A. , Vaidya Shalmalee
Published: July 2009

Two measurement techniques to measure the conductivity of carbon veil sample, a new composite conductive material, are presented: the parallel plate cavity resonator method and the waveguide measurement method. Comparison between results obtained by these two methods is provided and an uncertainty analysis performed for both measurement methods. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2435–2438, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24661
Small‐size wireless wide area network loop chip antenna for clamshell mobile phone with hearing‐aid compatibility
Authors: Li Wei‐Yu , Wong Kin‐Lu
Published: July 2009

A loop chip antenna with an FR4 chip base suitable for clamshell mobile phone application to achieve wireless wide area network operation and hearing‐aid compatibility (HAC) is presented. The loop chip antenna is formed by a loop strip excited by a capacitively coupled feed, all printed on the surfaces of the FR4 chip base to achieve a small size of 1.35 cm3only. Two resonant loop paths are provided by the antenna and each loop path can generate its 0.5λ and 1.0λ resonant modes with good impedance matching. The excited loop resonant modes are formed into two wide operating bands for the antenna to cover GSM850/900 and GSM1800/1900/UMTS operations for both the open (talk) and closed (idle) states of the clamshell mobile phone. Furthermore, the loop antenna also excites small surface currents on the two ground planes of the clamshell mobile phone. In this case, weak near‐field EM fields in the vicinity of the mobile phone can be generated. Results show that the strengths of the near‐field E‐field and H‐field fall in the M3 or M4 Category, making the clamshell mobile phone with the proposed antenna to be an HAC communication device. The obtained specific absorption rate values in 1‐g and 10‐g head tissues also meet the limit of 1.6 and 2.0 W/kg, respectively. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2327–2335, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24665
All optical multi‐tap microwave filter with high sidelobe suppression using peak profile of ASE and one multiwavelength FBG
Authors: Xia Li , Aditya S. , Shum P. , Zhou Junqiang
Published: July 2009

A new all optical 10‐tap microwave filter is proposed using a broadband amplified spontaneous emission (ASE) light source and a single specially designed multiwavelength FBG. Measured results show that the sidelobe suppression is larger than 20 dB. The filter response is insensitive to the polarization state of light. This technique enables one to obtain a simple and low cost photonic microwave filter with a stable response. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2522–2524, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24666
Unsaturated polyester resin via chemical recycling of off‐grade poly(ethylene terephthalate)
Authors: Zahedi Ali Reza , Rafizadeh Mehdi , Ghafarian Seyed Reza
Published: July 2009

BACKGROUND: The chemical recycling of poly(ethylene terephthalate) (PET), e.g. bottles and fibre wastes, has been studied for many years. Among several methods proposed for chemical recycling of waste PET, glycolysis makes it possible to employ very low amounts of reactants and lower temperatures and pressures compared with critical methanol and thermal degradation. Furthermore, unlike hydrolysis under acidic or basic conditions, glycolysis does not cause any problems related to corrosion and pollution.

RESULTS: PET from off‐grades of industrial manufacture was depolymerized using excess glycol. The effects of the reaction time, volume of glycol and catalyst concentrations on the yield of the glycolysis products were investigated. A reaction time of 3 h, weight ratio (catalyst to PET) of 0.25 wt% and PET to ethylene glycol molar ratio of 1:5 were determined as suitable conditions for depolymerization. Then, the reaction of polyesterification of maleic anhydride (MA) and glycolysed products of PET was successfully performed at 160 and 190 °C for 8 h.

CONCLUSION: Differential scanning calorimetry and vapour pressure osmometry results for the product of the glycolysis reactions, under suitable condition, confirmed the structure of the desired product. This sample underwent reaction with MA to produce unsaturated polyester resin (UPR). The results of Fourier transform infrared and NMR spectroscopy confirmed that the UPR had been synthesized successfully. This is the first direct report on the glycolysis reaction of off‐grade products of petrochemical companies in order to regenerate raw materials or other secondary value‐added products. Copyright © 2009 Society of Chemical Industry
Burning Characteristics of Ammonium Nitrate‐based Composite Propellants Supplemented with Ammonium Dichromate
Authors: Kohga Makoto , Nishino Saeko
Published: July 2009

Ammonium nitrate (AN)‐based composite propellants have attracted much attention, primarily because of the clean burning nature of AN as an oxidizer. However, such propellants have some disadvantages such as poor ignition and low burning rate. Ammonium dichromate (ADC) is used as a burning catalyst for AN‐based propellants; however, the effect of ADC on the burning characteristics has yet to be sufficiently delineated. The burning characteristics of AN/ADC propellants prepared with various contents of AN and ADC have been investigated in this study. The theoretical performance of an AN‐based propellant is improved by the addition of ADC. The increase in the burning rate is enhanced and the pressure deflagration limit (PDL) becomes lower with increasing amount of ADC added. The increasing ratio of the burning rate with respect to the amount of ADC is independent of the AN content and the combustion pressure. The optimal amount of ADC for improving the burning characteristics has been determined.
Gastrointestinal system
Authors: Cheng Leo K. , O'Grady Gregory , Du Peng , Egbuji John U. , Windsor John A. , Pullan Andrew J.
Published: July 2009

The functions of the gastrointestinal (GI) tract include digestion, absorption, excretion, and protection. In this review, we focus on the electrical activity of the stomach and small intestine, which underlies the motility of these organs, and where the most detailed systems descriptions and computational models have been based to date. Much of this discussion is also applicable to the rest of the GI tract. This review covers four major spatial scales: cell, tissue, organ, and torso, and discusses the methods of investigation and the challenges associated with each. We begin by describing the origin of the electrical activity in the interstitial cells of Cajal, and its spread to smooth muscle cells. The spread of electrical activity through the stomach and small intestine is then described, followed by the resultant electrical and magnetic activity that may be recorded on the body surface. A number of common and highly symptomatic GI conditions involve abnormal electrical and/or motor activity, which are often termed functional disorders. In the last section of this review we address approaches being used to characterize and diagnose abnormalities in the electrical activity and how these might be applied in the clinical setting. The understanding of electrophysiology and motility of the GI system remains a challenging field, and the review discusses how biophysically based mathematical models can help to bridge gaps in our current knowledge, through integration of otherwise separate concepts. Copyright © 2009 John Wiley & Sons, Inc.

This article is categorized under:

Physiology > Mammalian Physiology in Health and Disease
Biophysics and dynamics of natural and engineered stem cell microenvironments
Authors: Keung Albert J. , Healy Kevin E. , Kumar Sanjay , Schaffer David V.
Published: July 2009

Stem cells are defined by their ability to self‐renew and to differentiate into one or more mature lineages, and they reside within natural niches in many types of adult and embryonic tissues that present them with complex signals to regulate these two hallmark properties. The diverse nature of these in vivo microenvironments raises important questions about the microenvironmental cues regulating stem cell plasticity, and the stem cell field has built a strong foundation of knowledge on the biochemical identities and regulatory effects of the soluble, cellular, and extracellular matrix factors surrounding stem cells through the isolation and culture of stem cells in vitro within microenvironments that, in effect, emulate the properties of the natural niche. Recent work, however, has expanded the field's perspective to include biophysical and dynamic characteristics of the microenvironment. These include biomechanical characteristics such as elastic modulus, shear force, and cyclic strain; architectural properties such as geometry, topography, and dimensionality; and dynamic structures and ligand profiles. We will review how these microenvironmental characteristics have been shown to regulate stem cell fate and discuss future research directions that may help expand our current understanding of stem cell biology and aid its application to regenerative medicine. Copyright © 2009 John Wiley & Sons, Inc.

This article is categorized under:

Developmental Biology > Stem Cell Biology and Regeneration
Analysis of Management Narrative to Understand Social Marketing Strategy: The Case of ‘Branding Logan City’
Authors: Russell David , Mort Gillian Sullivan , Hume Margee
Published: July 2009

This paper presents a unique city branding case applying narrative analysis to the marketing manager's account of his long running campaign to brand Logan City. The analysis finds that the campaign has many of the hallmarks of social marketing, but focuses strongly on citizen's positive self image and social capital development. Elements of city branding are employed but the approach is ‘self directed’, rather than the usual approach of ‘other directed’. The desired outcomes are a positive self and community image laying the foundation for a community confident to undertake various economic development tasks. Implications for social marketing theory and management and future research are discussed.
Adverse Situations Encountered by Adolescent Students Who Return to School Following Suspension
Authors: Yen Cheng‐Fang , Wang Hui‐Ting
Published: July 2009

This study aimed to investigate the adverse personal, family, peer and school situations encountered by adolescent students who had returned to school after being suspended. This was a large‐scale study involving a representative population of Taiwanese adolescents. A total of 8,494 adolescent students in Southern Taiwan were recruited in the study and completed the questionnaires. The relationships between their experiences of suspension from school and adverse personal, family, peer, and school situations were examined. The results indicated that 178 (2.1%) participants had been suspended from school at some time. Compared with students who had never been suspended, those who had experienced suspension were more likely to report depression, low self‐esteem, insomnia, alcohol consumption, illicit drug use, low family support, low family monitoring, high family conflict, habitual alcohol consumption, illicit drug use by family members, low rank and decreased satisfaction in their peer group, having peers with substance use and deviant behaviors, low connectedness to school, and poor academic achievement. These results indicate that adolescent students who have returned to school after suspension encounter numerous adverse situations. The psychological conditions and social contexts of these individuals need to be understood in depth, and intervention programs should be developed to help them to adjust when they return to school and to prevent school dropouts in the future.
Eccrine Porocarcinoma of the Auricle: A Case Report
Authors: Chang Ning‐Chia , Tsai Kun‐Bow
Published: July 2009

Eccrine porocarcinoma (EP) is a rare skin malignant lesion representing 0.005–0.01% of all cutaneous tumors. It is a tumor that most commonly present in elderly people aged over 60 years. Approximately 250 cases of EP have been reported since this disease was first described in 1963. However, only three cases occurring specifically on the ear (including the current case) have been documented in the literature to date. Based on the rarity of EP of the ear, we present this 78‐year‐old man with EP on the right ear lobule, which was diagnosed accidentally during the management of other unrelated problems. The etiology, diagnosis, treatment and prognosis of this disease are discussed, with a brief review of the literature in this report.
ON FIXED POINTS OF GENERALIZED SET-VALUED CONTRACTIONS
Authors: BENAHMED S. , AZÉ D.
Published: July 2009

Using a variational method introduced in [D. Azé and J.-N. Corvellec, ‘A variational method in fixed point results with inwardness conditions’, Proc. Amer. Math. Soc.134(12) (2006), 3577–3583], deriving directly from the Ekeland principle, we give a general result on the existence of a fixed point for a very general class of multifunctions, generalizing the recent results of [Y. Feng and S. Liu, ‘Fixed point theorems for multi-valued contractive mappings and multi-valued Caristi type mappings’, J. Math. Anal. Appl.317(1) (2006), 103–112; D. Klim and D. Wardowski, ‘Fixed point theorems for set-valued contractions in complete metric spaces’, J. Math. Anal. Appl.334(1) (2007), 132–139]. Moreover, we give a sharp estimate for the distance to the fixed-points set.
The Need for Study of Native Law
Authors: Roberts-Wray Kenneth
Published: July 2009

One occasionally meets people, even among those who have lived or served in Africa,2 who speak light-heartedly about the study of native law and native courts and seem to imply that it is an esoteric exercise of little more practical importance than, say, archaeology; but it is safe to say that these people cannot have had occasion to give much serious thought to the matter.
Waqfs in East Africa
Authors: Anderson J. N. D.
Published: July 2009

There can be no doubt that British courts have, in general, built up a most impressive record by, and today enjoy a well-deserved reputation for, their sympathetic and intelligent application of those religious or customary laws, evolved by peoples of a culture and background very different from their own, which they have so often been called upon to administer. But there can be no branch of the law in which Muslim peoples who are subject to the jurisdiction of British courts, or courts trained in English traditions, have been made to suffer so many frustrations—by the judicial infusion of alien ideas, by misinterpretation or basic ignorance of the Islamic doctrines, and even by what can only be termed a rigidity of mind which ill-accords with this illustrious tradition—as in the law of waqf.
Some Principles of the Law of Trusts in West Africa
Authors: Daniels W. C. Ekow
Published: July 2009

“Of all the exploits of equity, the largest and the most important is the invention and development of the trust.”

These were the words of Maitland.2 In the course of his lecture, the learned professor ascribed the invention of the Law of trusts to the work of English lawyers. Before going any further, it should be pointed out that the institution of trusts is one which is not peculiar to English law.
The Changing Scope of Urban Native Courts in Northern Rhodesia
Authors: White C. M. N.
Published: July 2009

Courts administering African customary law in addition, as a rule, to statute law within specified limits, have been characteristic of territories in Africa with a background of British colonial administration. Such courts operate or operated in both urban and rural areas and have been known at various times in different territories as native courts, local courts or customary courts. A general account of these courts and the nature of the dualism produced by their existence side by side with other courts of the judiciary is provided by R. E. Robinson.
Integration of Judicial Systems: The Recent Reform of the Local Courts Appeal System of Tanganyika
Authors: Lewis-Barned J. F. de S.
Published: July 2009

The year 1962 saw an important step towards further integration of the judicial system of Tanganyika.

Before describing what has taken place in recent months, it would perhaps be appropriate to sketch briefly the historical background of the Local Courts appeal system.

The German administration, whilst tacitly recognizing the existence of a system of customary law and procedure, in fact administered justice at District level through an officer similar to the British District Commissioner, who heard cases himself, though he was sometimes required to recognize a specific customary law. Sometimes he delegated his authority on his own initiative and in an ad hoc manner, either to leading persons such as the pre-existing Liwalis and Kadhis, or to Akidas who had been appointed by the Germans themselves. However, the actual responsibility for the administration of justice was not generally delegated nor were native courts defined or established until the advent of British administration.
The Acquisition of Family Land in Ghana
Authors: Woodman G. R.
Published: July 2009

This is an examination of the circumstances in which, according to legal authorities, land may become family land in the customary law of Ghana.3 There may occasionally be difficulty in discovering whether the acquisition was by a wider family or by a branch (or segment) of it, since each such smaller group constitutes a “family” for different purposes. Normally, however, the circumstances give a clear answer, and difficulties on this point rarely reach the courts. If, for example, the narrower family lived in a different part of the country, or acted in the transaction through its own head rather than the overall head, or was already regarded by members of the other branches as a separate entity conducting its own affairs, the acquisition will accrue to this smaller family. The only serious difficulties in this respect have occurred when the acquisition was by intestate succession, a means which will not be discussed in detail. Therefore the distinction drawn by Sarbah4 between “ancestral property” and “family property” will not be followed here.
Discriminatory Restrictions on Private Dispositions of Land in Tanganyika: A Second Look
Authors: Sawyerr G. F. Akilagpa
Published: July 2009

“A disposition of land belonging to a native in favour of a non-native or conferring on a non-native any rights over the land of a native shall not be operative unless it is in writing and unless and until it is approved by the Minister.” [Land (Law of Property and Conveyancing) Ordinance, s. 11(i).]
The Sources of Law In Tswana Tribal Courts: Legislation and Precedent
Authors: Schapera I.
Published: July 2009

The Tswana peoples referred to in this paper inhabit the Bechuanaland Protectorate, where they number altogether about 270,000. In pre-European times they derived their subsistence mainly from animal husbandry and the cultivation of crops, each household producing its own food. Today they are still essentially small-scale subsistence farmers. But to satisfy the new wants developed by contact with Western civilisation over the past century, many persons also pursue new occupations, including above all temporary wage-labour for Europeans. In some areas more than half the able-bodied men are away every year working in the Union of South Africa. Their absence, often prolonged, has led to conspicuous changes in traditional customs and beliefs, and, as will be seen from some of the examples given below, has also given rise to new grounds for litigation.
Contempt Of Court In Nigerian Criminal Law
Authors: Rewane O. N.
Published: July 2009

The more the self-government of Nigeria becomes a reality, the more important is the question of the independence of the judiciary and the more relevant is the question of the law of contempt of court. The judiciary is mainly staffed by British and Nigerian judges and magistrates drawn from the different national groups and regions of the Federation. It is therefore not impossible that as more cases of political interest go before the courts, the judges and magistrates may be exposed to unnecessary suspicion or pressures because of their places of origin, whatever the colour of their skins. Let me illustrate this point.
Opinions of Assessors in Criminal Trials in East Africa as to Native Custom
Authors: Gray John
Published: July 2009

In Tanganyika, Uganda, and Zanzibar all trials in the High Court take place with the aid of Assessors. The same rule applies in Kenya, except in the case of Europeans, when the trial is before a judge and jury. In trials with the aid of Assessors, as in the case of trial by jury, at the conclusion of the evidence and the addresses on behalf of the prosecution and the defence the Judge may sum up to the Assessors the evidence for the prosecution and the defence. In the relevant section in all four Criminal Procedure Codes the word preceding the words “sum up” is “may”. That is to say, there is no statutory obligation on the trial Judge to sum up the evidence, but, as said in Washington v. R. (1954), 21 E.A.C.A. 392, it is a very sound practice which is almost invariably followed by Judges in East African territories except in the very simplest cases. Furthermore, as held in R. v. Lute (1934), 1 E.A.C.A. 106, in all but the clearest cases, it is desirable that the Judge should make a note of the points put to the Assessors in such summing up, and the evidence which he has stated as supporting or otherwise each point.
Loans in Kenya on the Security of Chattels: II
Authors: Oulton A. D. M.
Published: July 2009

The economic aspects of the hire-purchase movement are well known and it is not intended to discuss them here. It will be sufficient to point out that hire-purchase finance enables people, in certain circumstances, to live by taking in, not each other's washing, but their own. This remarkable achievement was recently explained byThe Times:

“The reliance on funds from the public to finance consumer hire-purchase spending is, in fact, a paradox in that the public is ultimately financing itself. As it is pointed out in the second edition ofHire Purchase in a Free Society, the man who subscribes to a life endowment policy yet chooses to buy a car on hire-purchase rather than liquidate it may in effect be financing himself.”
Legal Education in East Africa
Authors: Allott A. N.
Published: July 2009

The London Conference on the Future of Law in Africa, meeting at Westminster from 28th December, 1959 to 8th January, 1960, and attended by leading judicial and legal representatives from many English-speaking African countries, incidentally examined the problem of legal education in and for Africa (for which see the Conference Record, Chapter 13). The discussions were centred on the problems of East Africa, since it was here that the absence of provision for local training was making itself most felt. Because of the gravity and urgency of the problem, the Conference recommended that a committee should be set up without delay to go into the whole matter.
The Common Law in Lesotho
Authors: Poulter Sebastian
Published: July 2009

Whereas the reception and operation of English law in West and East Africa have been the subject of much study over the last few years, the introduction and application of Roman-Dutch law in Southern Africa (apart from South Africa itself) have received scant treatment.1 This article deals only with the position in Lesotho and attempts to show the extent to which Lesotho's legal system is tied to that of the Republic of South Africa, and thus strengthens the geographical and economic bonds which link the two countries.
Native Custom, its Similarity to English Conventional Custom and its Mode of Proof
Authors: Hannigan A. St. J. J.
Published: July 2009

The rules respecting custom in Ghana (the Gold Coast) are found in the law reports, the statements of chiefs and elders, the works of textbook writers, both lawyers and anthropologists, and in the unreported decisions of the courts. It is important, however, to distinguish between the rules which have the force of law and those which have not. Here it is proposed to outline the mode of proof required before custom can be recognised as law, bearing in mind that an English judicial system has been imposed upon Ghana, working through a system of case law with its attendant precedents. It is further hoped to point the way to a possible method of ensuring the preservation of the indigenous customs, which is believed to be desirable in order to ensure their natural development.
Developments in Pledges of Land in Ghanaian Customary Law
Authors: Woodman Gordon R.
Published: July 2009

There are two principal methods whereby land may be used as security for a loan in Ghana. One is the customary law transaction called a mortgage by Sarbah.2 The other is the common law mortgage. It will be convenient to refer to the customary law transaction as a “pledge”, because the creditor obtains possession of the land, and the present article is not concerned with the use of chattels as security. Accordingly, “mortgage” will always mean a common law mortgage.
Towards a Definition of “Absolute Ownership”: II
Authors: Simpson S. R.
Published: July 2009

As I read Dr. Allott's article “Towards a definition of Absolute Ownership” I felt increasing dismay because it postulates and makes appear immensely difficult, a problem which in actual working practice barely exists at all. For over sixty years Settlement Officers in the Sudan have been successfully determining ownership without the help of any definition, and in Kenya, during the last five years, the ownership of over a million plots has similarly been decided by committees. Even in West Africa, where there has been no process of systematic adjudication, ownership has been determined in over three thousand cases in Lagos, and ownership is not defined. Indeed I am not familiar with any statute anywhere which does define it.
Civil Wrongs Under Customary Law In The Northern Regions Of The Somali Republic
Authors: Muhammad Haji N. A. Noor
Published: July 2009

Civil wrongs among Somalis are governed by customary law. Somalis have traditionally been pastoral nomads, and their customary law has been closely related to their social organization.
Judicial Review of Administrative Action in The Somali Republic
Authors: Muhammad Haji N. A. Noor
Published: July 2009

The Constitution of the Somali Republic provides that:“Administrative acts contrary to law…may be invalidated on the initiative of the interested parties in accordance with the provisions of the Constitution.”2
A Revolution in The Law of Succession of Malawi
Authors: Roberts Simon
Published: July 2009

The enactment in Malawi of the Wills and Inheritance (Kamuzu's Mbumba Protection) Ordinance, 1964, represents the most significant attempt at legal reform there in recent years. Its importance lies in the fact that it seeks to impose uniformity in an area of the law which had previously been dominated by diverse systems of customary rules. This piece of legislation is in no sense a codification or a restatement of the customary law; it strikes at the very roots of the existing customary systems. Although it is not the first attempt at reform in this area, it is novel in its ambitious aims and unequivocal implications of policy. Because of this, the degree of success which it enjoys will be closely followed by all those interested in the legal development of modern African states.
The Award of Compensation in Criminal Cases in East Africa
Authors: Brown Douglas
Published: July 2009

In East Africa the traditional division of “native justice” on the one side and “English law” on the other is gradually disappearing. Within the foreseeable future it is possible to visualize a single system of law administered by one judiciary. The fusion of customary law and modified English law has been, or is being, achieved with a remarkable lack of friction. Generally speaking, however, customary law has had to make greater sacrifices in achieving the fusion than its more powerful brother, the common and statutory law of the three states. The latter has made a few minor concessions; for example, when customary criminal law disappeared in Uganda in 1964, the Penal Code was amended to admit adultery as a statutory offence. Adultery had been an offence among all the different tribes in Uganda. But it is usually customary law which has had to change to achieve a single system of law.
Constitutional Development in Ethiopia
Authors: Selassie Bereket Habte
Published: July 2009

The origin and character of Ethiopian central institutions can be understood by reference to at least four main factors: the religious history of the country; its geography; its internal wars; and the advent of Islam, which cut it off from the World outside for several centuries, and affected the course of its history.