bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bragg reflectors containing left‐handed materials
Authors: Ruppin R. 
Published: August 2003

AbstractEffects of the frequency‐dependence of the permeability and permittivity of a left‐handed material (LHM), when used as one of the components of a Bragg reflector, are investigated. It is found that typical broad Bragg reflectivity peaks appear in the frequency range in which the material is not left‐handed. Inside the LHM range, the Bragg peaks are very narrow and of low intensity. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 494–495, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11100
Dual‐frequency and broadband characteristics of hybrid coupled slot antennas fed by coplanar waveguide
Authors: Chen Jin‐Sen 
Published: August 2003

AbstractA simple design of a hybrid coupled slot antenna, fed by coplanar waveguide with dual‐frequency or broadband operation, is presented. The proposed antenna is constructed by a coplanar waveguide (CPW) capacitively coupled slot‐loop antenna and a CPW inductively coupled dipole slot antenna. The dimensions of the two slot antennas decide the two resonant frequencies of the proposed antenna, respectively. Results show that the impedance bandwidth of the proposed broadband slot antenna is about 35%. Details of the proposed dual‐frequency and broadband designs are described and experimental results are presented and discussed. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 496–498, 2003; Published online in Wiley InterScience (www.interscience.wiley.com).
A foam‐base surface‐mountable shorted monopole antenna for WLAN application
Authors: Su Saou‐Wen , Wu Tzuenn‐Yih , Cheng Yuan‐Tung , Wong Kin‐Lu 
Published: August 2003

AbstractA surface‐mountable shorted monopole antenna, constructed by folding a branch‐line metal strip onto a foam base for 2.4/5.2/5.8‐GHz WLAN operation, is presented. The branch‐line metal strip is comprised of a longer arm, a shorter arm, and a matching arm. The longer and shorter arms generate, respectively, a lower resonant mode covering the 2.4‐GHz band (2400–2484 MHz) and an upper resonant mode covering the 5.2‐GHz (5150–5350 MHz) and 5.8‐GHz (5725–5875 MHz) bands, and good impedance matching for frequencies across the two resonant modes is easily achieved by adjusting the distance between the feeding point and the shorting point in the matching arm. Experimental results of a constructed prototype of the proposed antenna are presented. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 501–503, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11103
Group‐velocity matched‐fiber Raman wavelength converter for the flexible optical communications network
Authors: Tang Ming , Ghafouri‐Shiraz H. 
Published: August 2003

AbstractThe feasibility of a group‐velocity matched‐fiber Raman wavelength converter using extended birefringent fiber has been demonstrated, in which high‐power pumping laser diodes are used to achieve sufficient four‐wave mixing (FWM) Raman conversion. Based on our proposed novel model, the power intensity and temporal properties of the converted wave (10 Gb/s and 20 Gb/s, from C‐band to L‐band) have been demonstrated. The ultra‐wide Raman gain spectrum and the tunability of the fiber birefringence make our model extremely suitable for broadband wavelength‐convertible lightwave communication. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 504–506, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11104
Multi‐frequency characteristics of annular‐ring slot antennas
Authors: Chen Jin‐Sen 
Published: August 2003

AbstractThe design of an annular‐ring slot antenna for obtaining multi‐frequency operation using a coplanar waveguide feed (CPW) or microstrip line feed is presented. The operating frequencies are obtained by means of multiple radiating elements. Details of the proposed designs are investigated by experimental as well as theoretical studies. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 506–511, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11105
Parallel‐plate waveguides with Kronig Penney morphology as photonic band‐gap filters
Authors: Gómez Álvaro , Lakhtakia Akhlesh , Solano Miguel A. , Vegas Angel 
Published: August 2003

AbstractGuided wave propagation in a parallel‐plate waveguide with Kronig–Penney morphology is analyzed. Modes in the photonic band‐gap (PBG) structure can be classified as either transverse electric or transverse magnetic with respect to the propagation direction. Above the modal cut‐off frequencies, band gaps exist where propagation is forbidden. The locations and the widths of the band gaps depend on modal order, waveguide height, and the permittivity contrast and relative volumetric proportion of the two materials constituting the unit cell of the PBG structure. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 511–514, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11106
Advances in sputter depth profiling using AES
Authors: Hofmann Siegfried 
Published: August 2003

AbstractSputter depth profiling using AES is a routinely applied method in surface, interface and thin‐film analysis. After about 30 years of constant progress the present state is characterized by improved instrumentation, e.g. sample rotation capabilities and low‐energy ion guns, as well as by improved quantification methods for the raw data depth profiles. Profile quantification by reconstruction of the original in‐depth distribution of composition using the so‐called (atomic) mixing–roughness–information depth (MRI) model has proved to be a powerful tool for extracting more precise and extended information of the measured profiles, e.g. quantification with submonolayer accuracy, intrinsic determination of the sputtering rate and determination of localized interdiffusion coefficients as low as 10−22 m2 s−1 were obtained. Because the MRI model is based on physically well‐defined parameters, it can be applied successfully to other profiling techniques such as SIMS or GDOES. Although in many cases the MRI model can be applied in its original version, some materials require modification by a preferential sputtering coefficient. Further modifications will be necessary to take care of non‐linear effects in the concentration dependence and in the compositional distribution within the atomic mixing zone. In summary, quantitative depth profiling using AES has now attained an advanced stage, where its combination with the MRI model is being introduced in commercial instrument software. Copyright © 2003 John Wiley & Sons, Ltd.
Surface characterization and depth profile analysis of glasses by r.f. GDOES
Authors: Le Coustumer Philippe , Motelica‐Heino Mikael , Chapon Patrick , François Saint‐Cyr Hugues , Payling Richard 
Published: August 2003

AbstractThe characterization of surfaces, interfaces and interphases in glasses is analytically challenging and may benefit from recent developments in radiofrequency glow discharge optical emission spectroscopy (r.f. GDOES) applied to non‐conductive materials. Thus, the main thrust of this study is to evaluate the potential of r.f. GDOES for the characterization of glass surfaces, physical heterogeneities such as discrete layers and continuous interphases and the distribution of elements in glass materials. Model glasses with increasing structural and chemical complexity thus were analysed using a Jobin Yvon GDOES system (5000 RF): the glasses included a multilayered glass (triple‐coated glass), two photoreactive glasses (with potential chemical diffusion gradients) and acid‐leached glass with an alteration layer. Concurrently, surface characterization of the glasses was conducted using scanning electron microscopy or transmission electron microscopy with energy‐dispersive x‐ray imaging to assess the chemical and physical gradients in the materials and to investigate the glow discharge sputtering process. From this the capability of r.f. GDOES for elemental depth profiling in glass materials is established. However, although the sputtering rates for glass are greatly reduced compared with conductive materials (∼2 nm s−1 compared with 50–150 nm s−1 for metals), r.f. GDOES offers good spatial depth resolution (nm) and elemental sensitivity for several applications, such as the characterization of interfaces or interphases and the determination of chemical gradients in glasses. Furthermore, the technique distinguishes submicrometre discrete layers in the coated glass, and the diffusion of elements within glass matrices may be monitored. Copyright © 2003 John Wiley & Sons, Ltd.
The effect of total hip arthroplasty surgical approach on gait
Authors: Madsen Michael S. , Ritter Merrill A. , Morris Harold H. , Meding John B. , Berend Michael E. , Faris Phillip M. , Vardaxis Vassilios G. 
Published: August 2003

AbstractThis study examined the effect of the surgical approach used in total hip arthroplasty (THA) on gait mechanics six months following surgery. Quantitative gait analysis was performed on 29 subjects: 10 anterolateral (A‐L) and 10 posterolateral (P‐L) THA patients and nine able‐bodied, velocity‐matched subjects. Discriminant function analysis was used to determine the distinction of the groups with respect to sagittal plane hip range of motion, index of symmetry, trunk inclination, pelvic drop, hip abduction, and foot progression angles. The A‐L group had the largest trunk inclination (3.0 ± 2.4°) and the smallest hip range of motion (34.0 ± 7.4°). Both THA groups demonstrated greater asymmetry as expressed by the smaller symmetry index (0.97 ± 0.04 for A‐L and 0.98 ± 0.05 for the P‐L) than the able‐bodied group (0.99 ± 0.01). The classification procedure correctly classified 89% of the control group cases, 90% of the A‐L cases, and 50% of the P‐L cases. These results support the conclusion that six months following surgery, the gait of the majority (85%) of THA patients has not returned to normal. The A‐L patients displayed distinct gait patterns, while a small percentage (30%) of the P‐L patients demonstrated normal gait. While these differences are statistically significant, the clinical significance is unknown and linked to the duration that they persist. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Quadriceps femoris muscle weakness and activation failure in patients with symptomatic knee osteoarthritis
Authors: Lewek Michael D. , Rudolph Katherine S. , Snyder‐Mackler Lynn 
Published: August 2003

AbstractPurpose: Quadriceps weakness is common in patients with knee osteoarthritis (OA), and has been attributed to failure of voluntary activation. Methodological differences may have contributed to previous reports of extensive failure of voluntary activation in patients with osteoarthritis. The purpose of this study was to determine the extent of quadriceps muscle weakness and activation failure in middle aged patients with symptomatic medial knee osteoarthritis using maximum voluntary isometric contractions (MVIC) and a burst superimposition technique.Methods: Measurements of quadriceps MVIC and extent of voluntary activation were made in 12 subjects with knee OA and 12 similarly aged uninjured subjects. Voluntary activation was tested by superimposing a train of electrical stimulation on a maximal effort volitional contraction of the quadriceps muscle.Results: The group of subjects with knee OA had significantly less quadriceps strength relative to body mass index (BMI) than the group of control subjects (p = 0.010). No difference in voluntary activation was observed (p = 0.233), however, 50% of the OA group, and only 25% of the control group failed to fully activate the quadriceps.Discussion: The finding of quadriceps weakness is consistent with past literature. Providing adequate instruction, feedback, and several attempts to maximally contract the muscle likely yielded greater volitional activation (thus less activation failure) than had been reported previously. This finding has implications for the rehabilitation of weakened quadriceps in patients with knee osteoarthritis. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
The effects of patient age on human osteoblasts' response to Ti–6Al–4V implants in vitro
Authors: Zhang Hai , Lewis Courtland G. , Aronow Michael S. , Gronowicz Gloria A. 
Published: August 2003

AbstractOsseointegrated implants are a common therapy for the elderly population as lifespan increases. Understanding the effects of age and sex on osseointegration is important for successful implant therapy. Therefore, the response of primary human osteoblasts (HOB) to implant materials was studied. HOBs were obtained by outgrowth of cells from bone from orthopaedic procedures and categorized as Young (Y), < 15; Middle (M), 30–50; and Old (O), > 60 years old. Initially the HOB phenotype was determined on tissue culture plastic. Alkaline phosphatase (ALP) staining and activity were significantly increased in HOBs from older patients. Message levels of type I collagen (COL), bone sialoprotein (BSP) and ALP were significantly higher (from 2.3‐ to 3.8‐fold) in Y subjects compared to M and O patients at 2 weeks. Studies of the response of HOBs to implant materials were undertaken using Ti–6A1–4V disks prepared in a manner similar to orthopaedic implants. A 1.4‐fold (p < 0.05) increase in cell attachment was found in HOBs from Y compared with O in female subjects but not in male subjects. Cell proliferation at 24 h was not significantly different by age or sex, nor was DNA content different at 2 and 4 weeks. Mineralization in HOB‐implant cultures was 2.3‐fold higher in Y than in O, and 1.7‐fold higher in Y compared to M HOBs from female but not male subjects at 4 weeks. Northern blot and RT‐PCR analysis at 2 weeks of culture showed significantly higher levels (1.6–2.3‐fold) of COL, BSP, and osteocalcin (OC) mRNAs in Y HOBs compared to M and O HOBs from female subjects. We conclude that human osteoblasts from older female patients have a decreased ability to form bone on implants. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Microcirculatory effects of pulsed electromagnetic fields
Authors: Smith Thomas L. , Wong‐Gibbons Donna , Maultsby Jane 
Published: August 2003

AbstractPurpose: Pulsed electromagnetic fields (PEMF) are used clinically to expedite healing of fracture non‐unions, however, the mechanism of action by which PEMF stimulation is effective is unknown. The current study examined the acute effects of PEMF stimulation on arteriolar microvessel diameters in the rat cremaster muscle. The study hypothesis was that PEMF would increase arteriolar diameters, a potential mechanism involved in the healing process.Methods: Local PEMF stimulation/sham stimulation of 2 or 60 min duration was delivered to the cremaster muscle of anesthetized rats. Arteriolar diameters were measured before and after stimulation/sham stimulation using intravital microscopy. Systemic hemodynamics also were monitored during PEMF stimulation.Results: Local PEMF stimulation produced significant (p< 0.001) vasodilation, compared to pre‐stimulation values, in cremasteric arterioles in anesthetized rats (n= 24). This dilation occurred after 2 min of stimulation (9% diameter increase) and after 1 h of stimulation (8.7% diameter increase). Rats receiving “sham” stimulation (n= 15) demonstrated no statistically significant change in arteriolar diameter following either “sham” stimulation period. PEMF stimulation of the cremaster (n= 4 rats) did not affect systemic arterial pressure or heart rate, nor was it associated with a change in tissue environmental temperature.Conclusions: These results support the hypothesis that local application of a specific PEMF waveform can elicit significant arteriolar vasodilation. Systemic hemodynamics and environmental temperature could not account for the observed microvascular responses. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Intramatrix events during cryopreservation of porcine articular cartilage using rapid cooling
Authors: Jomha N. M. , Anoop P. C. , McGann L. E. 
Published: August 2003

AbstractCryopreservation of articular cartilage may improve long‐term transplantation results if cell and matrix integrity can be maintained. This study examined intramatrix events in intact porcine articular cartilage that occurred during a rapid‐cooling technique with various concentrations of dimethyl sulfoxide (DMSO) (1, 3, 5, 6 and 7 M). Thermocouples were inserted into the solution and in the cartilage matrix to record the temperature during rapid cooling. In addition, scanning electron microscopy of freeze‐substituted samples was performed and quantitatively evaluated for the areas representing ice in the matrix. The results of this study showed that low concentrations of DMSO resulted in the largest temperature gradient between the matrix and the surrounding solution, which occurred near the freezing point of the cryoprotectant solution. At higher concentrations of DMSO, the peak temperature gradient occurred near the glass transition temperature. The temperature measurements suggested that a significant amount of ice formed within the matrix at lower DMSO concentrations. At higher DMSO concentrations that resulted in vitrification of the external solution, there was evidence of some ice in the matrix. The scanning electron micrographs demonstrated significantly more matrix disruption (likely due to ice formation) (P < 0.02) in the lower DMSO concentrations (1 and 5 M) while the 6 M DMSO concentration demonstrated minimal matrix disruption. Cryopreservation of articular cartilage with a rapid‐cooling technique and high concentrations of DMSO resulted in partial vitrification of the matrix and significantly less matrix disruption. It appears that successful cryopreservation of viability and function in articular cartilage will require high concentrations of cryoprotectants and rapid cooling. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
A biomechanical study of lumbar spondylolysis based on a three‐dimensional finite element method
Authors: Chosa Etsuo , Totoribe Koji , Tajima Naoya 
Published: August 2003

AbstractBiomechanical analyses under compression only, and for a combination of flexion, extension, rotation, and lateral bending were performed to evaluate the stress of the interarticular portion of the lumbar vertebra using a nonlinear three‐dimensional finite element method. A detailed three‐dimensional L4–L5 motion segment model was developed that took into consideration the material nonlinearities of ligaments and annular fibers and the contact nonlinearities of facet joints. For a more accurate examination, the separation of cortical bone and cancellous bone for both posterior and anterior elements were also considered. The stress in the pars interarticularis was weakest under compression alone, but stronger under compression with lateral bending loading, with flexion, with rotation, and with extension. Under each loading condition, the region of the stress concentration was consistent with the separated region of the spondylolysis observed in clinical situations. Since the stress in the pars interarticularis was high under extension and rotation in particular, those loadings were suggested to be relatively high risk factors leading to spondylolysis. © 2003 Published by Elsevier Ltd. on behalf of Orthopaedic Research Society.
Scholars in Households: Refiguring the Learned Habitus, 1480–1550
Authors: Algazi Gadi 
Published: August 2003

ArgumentUntil the fifteenth century, celibacy was the rule among Christian scholars of northwestern Europe. Celibacy was a major element of the codified cultural representation of the scholar and his specific way of life, sustained by peculiar institutional arrangements and daily routines. Founding family households implied therefore a major reorganization of the scholar’s way of life. Broadly speaking, this involved refashioning the scholarly habitus (understood as a system of durable and transposable social dispositions), redefining social relations, and developing the necessary material infrastructure. The paper focuses on three aspects of this process during a period characterized by uncertainty and experimentation. It discusses the structure of scholars’ families, arguing that at least until the middle of the sixteenth century, received models still persisted, while new viable models for articulating family reproduction with the transmission of scholarly dispositions had not yet crystallized. It then turns to the reorganization of domestic space, focusing on the different uses of the study to manage social distance and regulate domestic relations. Finally, among the different manifestations of the scholarly habitus, it argues that the emotional detachment of learned men was itself a learned habit. The well-documented discussion of competing options for organizing scholars’ family households and cultivating an acquired nature in academic settings provides an exceptional occasion to examine the way a group habitus is reshaped and, explore the cultural work involved in this process.
On the Professorial Voice
Authors: Clark William 
Published: August 2003

ArgumentMuch recent research has established the importance of visualization in modern science. This essay treats, instead, of the continued importance of the aural and oral: the professorial voice. The professor remains important for science since so many scientists still instantiate this persona and, as is here argued, a “voice” constitutes an essential feature of it. The form of the essay reflects its contents. From the Middle Ages until well into the modern era, the archetypal professorial genre was the disputation, an oral event recast in written form. Apropos of the traditional disputation, this essay begins with a disquisition more or less to the point. It concerns Nietzsche’s first major publication, which violated norms for the proper professorial voice, thus accelerated the destruction of his academic career. The essay then presents six theses on the professorial voice. The theses treat relevant aspects of the professorial voice from the Sophists onward. It is argued, in Weberian terms, that the professorial voice or persona embodies elements of charismatic and traditional authority which coexist with and condition the rational authority or “objectivity” of science.
Experimentalists in the Republic of Letters
Authors: Otto Sibum H. 
Published: August 2003

ArgumentWithin the Republic of Letters the art of experiment led to immense reorientation and an extensive redrawing of the enlightened map of natural knowledge. This paper will investigate the formative period of the exact sciences from the late eighteenth to the nineteenth century when the persona of the experimentalist as a scientific expert was shaped. The paper focuses on Moritz Hermann Jacobi’s experimental knowledge derived from his modeling of an electro-magnetic self-acting machine and the social and epistemological problems of its integration into traditional academic life. His struggle to achieve academic recognition and credibility for his experimental work reflects not just his individual quandary, but important structural problems of the historical development of experimental knowledge traditions and science in what has been called the “second scientific revolution.”