bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection of Cross-Reactivity for Atopic Immunoglobulin E against Multiple Allergens
Authors: Chiou Yee-Hsuan , Yuo Chung-Yee , Wang Lin-Yu , Huang Shiao-ping
Published: March 2003

The existence of specific immunoglobulin E (IgE) allows us to determine the allergens that cause the allergic disease. For the purposes of allergen avoidance and immunotherapy, the measurement of specific IgE is widely applied in clinical laboratories. However, if IgE from the serum of an allergic patient exhibits reactivity to multiple allergens, it would cause a problem. The present study analyzes whether the serum IgE with multiple reactivity is due to the presence of unique IgE against the common epitope shared by different allergens or the presence of multiple IgEs against different epitopes on different allergens. The quantitative-competitive inhibition tests and the immunoblotting were applied to analyze the immunosimilarity among examined allergens. The result shows that the competitive inhibition of IgE binding between shrimp and crab allergens is higher than those between either shrimp and cockroach or between crab and cockroach. Furthermore, the results of immunoblotting are consistent with those of quantitative-competitive inhibition tests. These results allow us to detect the cross-reactivity for atopic IgE against multiple allergens.
Rapid Detection of Contagious Bovine Pleuropneumonia by a
Mycoplasma mycoides
subsp.
mycoides
SC Capsular Polysaccharide-Specific Antigen Detection Latex Agglutination Test
Authors: March John B. , Kerr Karen , Lema Benedict
Published: March 2003

A latex agglutination test (LAT) has been developed for the diagnosis of contagious bovine pleuropneumonia (CBPP). The latex microspheres were coated with MmmSC polyclonal immunoglobulin G antiserum and detected MmmSC antigen in the serum of cattle infected with CBPP and in growth medium containing MmmSC. The specific antigen recognizsed by this test appeared to be the capsular polysaccharide (CPS). The LAT recognized all 23 strains of MmmSC examined in this study, with a sensitivity level of 2 ng of CPS, or the equivalent of 5 × 10
3
CFU, in a reaction volume of 0.03 ml. Therefore, rapid identification of MmmSC cultures should be possible. Agglutination was also observed with the related goat pathogens and “
Mycoplasma mycoides
” cluster members
Mycoplasma mycoides
subsp.
mycoides
large colony biotype (four of six strains positive) and
Mycoplasma mycoides
subsp.
capri
(three of six strains positive), in agreement with the suggestion that these latter two mycoplasmas may in fact represent a single species (although collectively exhibiting two capsular serotypes). Comparisons in diagnosis with the complement fixation test (CFT) were made by using African field sera from CBPP-infected cattle. After 2 (or 3) min of incubation, the test detected 55% (or 61%) of CFT-positive sera and 29% (or 40%) of CFT-negative sera, with an overall correlation in diagnosis of 62% (or 61%). The rates for false-positive diagnoses made by using “known” CBPP-negative sera from the United Kingdom were 3 or 13% after 2 or 3 min of incubation, respectively. The data agree with previous findings that some CBPP CFT-negative misdiagnoses may occur due to “antibody eclipsing” by excess circulating antigen. The LAT combines low cost and high specificity with ease of application in the field, without the need for any specialist training or equipment.
Performance of Five Serological Assays for Diagnosis ofRhodococcus equiPneumonia in Foals
Authors: Giguère Steeve , Hernandez Jorge , Gaskin Jack , Prescott John F. , Takai Shinji , Miller Corey
Published: March 2003

The performance of four enzyme-linked immunosorbent assays (ELISAs) (ELISA-6939, ELISA-33701, ELISA-VapA, and ELISA-California) and an agar gel immunodiffusion test for diagnosis ofRhodococcus equipneumonia in foals was evaluated. Antibody concentrations of foals with culture-confirmedR. equipneumonia (n= 41) were compared to those of age-matched pasturemates that remained clinically healthy during the entire breeding season (n= 24). For each serological assay evaluated, selection of a low cutoff resulted in high sensitivity but low specificity. Increasing the cutoff value resulted in better specificity but to the detriment of sensitivity. The best diagnostic performance was achieved with ELISA-California at a cutoff of 40%, resulting in a sensitivity of 59% and a specificity of 88%. We conclude that current serological assays do not differentiate between diseased and clinically healthy foals.
Inhibition of Pneumococcal Adherence to Human Nasopharyngeal Epithelial Cells by Anti-PsaA Antibodies
Authors: Romero-Steiner Sandra , Pilishvili Tamar , Sampson Jacquelyn S. , Johnson Scott E. , Stinson Annie , Carlone George M. , Ades Edwin W.
Published: March 2003

The role of pneumococcal (Pnc) surface adhesin A (PsaA) in the adherence of
Streptococcus pneumoniae
(pneumococcus) to host cells is not well defined. We examined the effect of anti-PsaA antibodies in an inhibition of adherence assay using Detroit 562 nasopharyngeal human epithelial cells. Rabbit polyclonal (Pab) anti-recombinant PsaA (rPsaA) sera, a purified mouse monoclonal antibody (MAb) (MAb 6F62G8E12), and 22 healthy adult sera with known anti-PsaA IgG levels (obtained by enzyme-linked immunosorbent assay) were evaluated for their abilities to inhibit Pnc adherence to confluent monolayers (measured as percent reduction in CFU counts compared to those of uninhibited controls). Pnc adherence was dependent on capsular phenotype (no or low adherence for opaque strains). With an inoculum of 10
4
to 10
5
bacteria/well, the mean ± standard deviation count in controls was 163 ± 32 CFU/well for transparent strains. Low adherence was observed for a PsaA-minus mutant even at higher inoculum doses. Mean percent inhibitions of adherence with Pab and MAb were 54 and 50%, respectively. Adult sera showed inhibition in a dose-response fashion with a range of 98 to 8%, depending on the serum anti-PsaA antibody concentration. Absorption of Pab with rPsaA restored Pnc adherence to control levels. Absorption of sera with a PsaA-minus mutant did not result in a significant decrease (
P
>0.05) of inhibition of adherence activity. Additionally, nearly 100% of Pnc adherence was inhibited by lipidated rPsaA at 2.5 μg/ml. Our data support the argument that PsaA is an adhesin that mediates Pnc adherence to human nasopharyngeal cells. This functional assay may be useful in evaluating antibodies elicited in response to PsaA vaccination.
Lipoteichoic Acids fromLactobacillusStrains Elicit Strong Tumor Necrosis Factor Alpha-Inducing Activities in Macrophages through Toll-Like Receptor 2
Authors: Matsuguchi Tetsuya , Takagi Akimitsu , Matsuzaki Takeshi , Nagaoka Masato , Ishikawa Kimika , Yokokura Teruo , Yoshikai Yasunobu
Published: March 2003

Lactobacilli are nonpathogenic gram-positive inhabitants of microflora. At least someLactobacillusstrains have been postulated to have health beneficial effects, such as the stimulation of the immune system. Here we examined the stimulatory effects of lactobacilli on mouse immune cells. All six heat-killedLactobacillusstrains examined induced the secretion of tumor necrosis factor alpha (TNF-α) from mouse splenic mononuclear cells, albeit to various degrees. When fractionated subcellular fractions ofLactobacillus caseiwere tested for NF-κB activation and TNF-α production in RAW264.7, a mouse macrophage cell line, the activity was found to be as follows: protoplast > cell wall ≫ polysaccharide-peptidoglycan complex. Both crude extracts and purified lipoteichoic acids (LTAs) from twoLactobacillusstrains,L. caseiandL. fermentum, significantly induced TNF-α secretion from RAW264.7 cells and splenocytes of C57BL/6, C3H/HeN, and C3H/HeJ mice but not from splenocytes of C57BL/6TLR2−/−mice.LactobacillusLTA induced activation of c-Jun N-terminal kinase activation in RAW264.7 cells. Furthermore, in HEK293T cells transected with a combination of CD14 and Toll-like receptor 2 (TLR2), NF-κB was activated in response toLactobacillusLTA. Taken together, these data suggest that LTAs from lactobacilli elicit proinflammatory activities through TLR2.
Performance Characteristics of a Rapid New Immunochromatographic Test for Detection of Antibodies to Human Immunodeficiency Virus
Authors: Ribeiro-Rodrigues Rodrigo , Ferreira da Silva Pinto Neto Lauro , Cunha Carla B. , Cabral Valéria P. , Dietze Reynaldo
Published: March 2003

A new immunochromatographic rapid test (Rapid Check HIV 1&2; Núcleo de Doenças Infecciosas) for the detection of antibodies to human immunodeficiency virus type 1 and type 2 in human samples (whole blood, serum, and plasma) was evaluated and compared to the commercially available Determine (Abbott Laboratories). When whole-blood samples were evaluated, the specificity and sensitivity of both tests were 100%. However, when plasma samples were used, sensitivity for the Rapid Check HIV 1&2 and the Determine tests were 100 and 98.58%, respectively. The observed specificity for plasma samples was 98.94% for the Rapid Check HIV 1&2 and 96.97% for the Determine test. The results presented here are encouraging and support the adoption of both tests as an alternative to enzyme-lined immunosorbent assay and/or Western blots in regions where laboratorial infrastructure is not available or for use in the management of occupational accidents for healthcare workers.
RNase L Levels in Peripheral Blood Mononuclear Cells: 37-Kilodalton/83-Kilodalton Isoform Ratio Is a Potential Test for Chronic Fatigue Syndrome
Authors: Tiev Kiet Phong , Demettre Edith , Ercolano Philippe , Bastide Lionel , Lebleu Bernard , Cabane Jean
Published: March 2003

Chronic fatigue syndrome (CFS) is a disorder characterized by debilitating fatigue associated with immunological abnormalities. The etiology remains unclear. A low-molecular-mass (37 kDa) isoform of RNase L has been described in peripheral blood mononuclear cell (PBMC) extracts, and the ratio of two isoforms of RNase L (37 kDa/83 kDa) has been proposed as a potential biochemical marker of CFS. In a prospective case-control study, we tested whether the RNase L 37-kDa/83-kDa ratio could discriminate a SFC population. We compared the ratio of RNase L isoforms in PBMCs from 11 patients with CFS (6 women and 5 men; mean age ± standard deviation, 43.2 ± 13.8 years) and PBMCs from 14 healthy well-matched volunteers (10 women and 4 men; age, 39.1 ± 11.6 years). A ratio of RNase L of 0.4 used as a threshold allowed diagnosis of CFS with high sensitivity (91%; 95% confidence interval [CI], 57 to 99%) and specificity (71%; 95% CI, 41 to 90%). The positive and negative prognostic values were 71% (95% CI, 41 to 90%) and 91% (95% CI, 57 to 99%), respectively. In the absence of acute infection or chronic inflammation, a high RNase L ratio could distinguish CFS patients from healthy volunteers. Additional large studies and follow-up studies are required to confirm the stability of this high ratio of RNase L isoforms in a CFS group.
Nucleoporin p62 Antibodies in a Case of Mixed Connective Tissue Disease
Authors: Kraemer Doris M. , Kraus Michael R. , Kneitz Christian , Tony Hans-Peter
Published: March 2003

Mixed connective tissue disease is an overlap syndrome characterized by features of different systemic autoimmune diseases and a high titer of U1-snRNP antibodies. We examine here the autoantibodies to nucleoporin p62 in a severe case of mixed connective tissue disease in a young male patient. Thus far, p62 antibodies have mainly been described in cases of primary biliary cirrhosis. We speculate that the presence of p62 antibodies is an indication of a poor prognosis in connective tissue disorders.
Agrobacterium
-Mediated Plant Transformation: the Biology behind the “Gene-Jockeying” Tool
Authors: Gelvin Stanton B.
Published: March 2003

Agrobacterium tumefaciens and related Agrobacterium species have been known as plant pathogens since the beginning of the 20th century. However, only in the past two decades has the ability of Agrobacterium to transfer DNA to plant cells been harnessed for the purposes of plant genetic engineering. Since the initial reports in the early 1980s using Agrobacterium to generate transgenic plants, scientists have attempted to improve this “natural genetic engineer” for biotechnology purposes. Some of these modifications have resulted in extending the host range of the bacterium to economically important crop species. However, in most instances, major improvements involved alterations in plant tissue culture transformation and regeneration conditions rather than manipulation of bacterial or host genes. Agrobacterium-mediated plant transformation is a highly complex and evolved process involving genetic determinants of both the bacterium and the host plant cell. In this article, I review some of the basic biology concerned with Agrobacterium-mediated genetic transformation. Knowledge of fundamental biological principles embracing both the host and the pathogen have been and will continue to be key to extending the utility of Agrobacterium for genetic engineering purposes.
Cytokinesis in Bacteria
Authors: Errington Jeffery , Daniel Richard A. , Scheffers Dirk-Jan
Published: March 2003

Work on two diverse rod-shaped bacteria, Escherichia coli and Bacillus subtilis, has defined a set of about 10 conserved proteins that are important for cell division in a wide range of eubacteria. These proteins are directed to the division site by the combination of two negative regulatory systems. Nucleoid occlusion is a poorly understood mechanism whereby the nucleoid prevents division in the cylindrical part of the cell, until chromosome segregation has occurred near midcell. The Min proteins prevent division in the nucleoid-free spaces near the cell poles in a manner that is beginning to be understood in cytological and biochemical terms. The hierarchy whereby the essential division proteins assemble at the midcell division site has been worked out for both E. coli and B. subtilis. They can be divided into essentially three classes depending on their position in the hierarchy and, to a certain extent, their subcellular localization. FtsZ is a cytosolic tubulin-like protein that polymerizes into an oligomeric structure that forms the initial ring at midcell. FtsA is another cytosolic protein that is related to actin, but its precise function is unclear. The cytoplasmic proteins are linked to the membrane by putative membrane anchor proteins, such as ZipA of E. coli and possibly EzrA of B. subtilis, which have a single membrane span but a cytoplasmic C-terminal domain. The remaining proteins are either integral membrane proteins or transmembrane proteins with their major domains outside the cell. The functions of most of these proteins are unclear with the exception of at least one penicillin-binding protein, which catalyzes a key step in cell wall synthesis in the division septum.
Bacteriophage T4 Genome
Authors: Miller Eric S. , Kutter Elizabeth , Mosig Gisela , Arisaka Fumio , Kunisawa Takashi , Rüger Wolfgang
Published: March 2003

Phage T4 has provided countless contributions to the paradigms of genetics and biochemistry. Its complete genome sequence of 168,903 bp encodes about 300 gene products. T4 biology and its genomic sequence provide the best-understood model for modern functional genomics and proteomics. Variations on gene expression, including overlapping genes, internal translation initiation, spliced genes, translational bypassing, and RNA processing, alert us to the caveats of purely computational methods. The T4 transcriptional pattern reflects its dependence on the host RNA polymerase and the use of phage-encoded proteins that sequentially modify RNA polymerase; transcriptional activator proteins, a phage sigma factor, anti-sigma, and sigma decoy proteins also act to specify early, middle, and late promoter recognition. Posttranscriptional controls by T4 provide excellent systems for the study of RNA-dependent processes, particularly at the structural level. The redundancy of DNA replication and recombination systems of T4 reveals how phage and other genomes are stably replicated and repaired in different environments, providing insight into genome evolution and adaptations to new hosts and growth environments. Moreover, genomic sequence analysis has provided new insights into tail fiber variation, lysis, gene duplications, and membrane localization of proteins, while high-resolution structural determination of the “cell-puncturing device,” combined with the three-dimensional image reconstruction of the baseplate, has revealed the mechanism of penetration during infection. Despite these advances, nearly 130 potential T4 genes remain uncharacterized. Current phage-sequencing initiatives are now revealing the similarities and differences among members of the T4 family, including those that infect bacteria other than Escherichia coli. T4 functional genomics will aid in the interpretation of these newly sequenced T4-related genomes and in broadening our understanding of the complex evolution and ecology of phages—the most abundant and among the most ancient biological entities on Earth.
NONLINEAR OPTICAL PROPAGATION PHENOMENA IN NEAR-TRANSITION CENTROSYMMETRIC PHOTOREFRACTIVE CRYSTALS
Authors: DELRE E. , CIATTONI A. , CROSIGNANI B. , DI PORTO P.
Published: March 2003

We relate on a series of optical nonlinear propagation phenomena, mediated by photorefraction, present in ferroelectric crystals heated above the Curie point, in proximity of the critical regime. In particular, we discuss centrosymmetric screening solitons, diffusion-driven anisotropic nonlinear diffraction, ellipticity locking, diffusion-driven solitons, and spatial beam head-on collisions.
QUANTUM THEORY OF PHOTOLUMINESCENCE FOR COHERENTLY EXCITED SEMICONDUCTOR QUANTUM-WELL SYSTEMS
Authors: KIRA M. , JAHNKE F. , KOCH S. W.
Published: March 2003

Photoluminescence of semiconductor quantum wells is studied using a fully quantized theory for the light-matter interaction. Quantum fluctuations of the light field lead to direct coupling between a coherent excitation and luminescence in other directions. Numerical results for the time evolution of the luminescence spectrum and emission intensity dynamics after a femtosecond pulse excitation are presented.
ALL-SOLID-STATE SUBNANOSECOND TUNABLE ULTRAVIOLET LASER SOURCES BASED ON Ce3+-ACTIVATED FLUORIDE CRYSTALS
Authors: LIU ZHENLIN , SARUKURA NOBUHIKO , DUBINSKII MARK A. , ABDULSABIROV R. YU. , KORABLEVA S. L.
Published: March 2003

Several practical all-solid-state tunable ultraviolet subnanosecond laser sources have been developed based on Ce 3+: LiLuF 4 (Ce:LLF) and Ce 3+: LiCaAlF 6 (Ce:LiCAF) active media pumped by the fifth and fourth harmonics of a regular Q-switched 10-ns Nd:YAG laser, respectively. The demonstrated tuning range of the Ce:LiCAF oscillator providing reproducibly-single-pulse output was 282 nm to 314 nm with the maximum output energy of 1 mJ. Tunable laser output from 223 nm to 232 nm was obtained by sum-frequency-mixing Ce:LiCAF laser output with fundamental output of a Q-sw Nd:YAG laser. The maximum subnanosecond Ce:LiCAF single-pulse output of 14 mJ was obtained in a "master oscillator-power amplifier" (MOPA) configuration.
PHASE-SELECTION OF IMAGE-BEARING FIELD COMPONENTS BY FREQUENCY UP-CONVERSION IN NONLINEAR CRYSTALS
Authors: ANDREONI ALESSANDRA , BONDANI MARIA , POTEMZA MARCO A. C. , VILLANI FULVIA
Published: March 2003

Second-harmonic cross-correlation is used to selectively detect the weak contribution remaining coherent with the incident field among the randomly de-phased contributions to an optical field that propagated through a scattering medium. It is shown to allow detection of opaque (reflecting) objects immersed in (located beyond) highly turbid media.
INTENSE THz-RADIATION SOURCES USING SEMICONDUCTORS IRRADIATED WITH FEMTOSECOND LASER PULSES IN A MAGNETIC FIELD
Authors: IZUMIDA SHINJI , ONO SHINGO , LIU ZHENLIN , OHTAKE HIDEYUKI , SARUKURA NOBUHIKO
Published: March 2003

We report significant enhancement of THz radiation from InAs under magnetic field irradiated with femtosecond pulses. The THz-radiation power is significantly enhanced and reaches sub-mW level in a 1.7-T magnetic field with 1.5-W excitation power. The THz-radiation power is related almost quadratically both to the magnetic field and excitation laser power. Furthermore, the radiation spectrum is found to be controlled by the excitation pulsewidth, chirp direction of the excitation pulse, and the magnetic field. Additionally, we have demonstrated a new method to generate THz radiation from a saturable Bragg reflector in a magnetic field.
BROAD BAND MID-INFRARED THz PULSE: MEASUREMENT TECHNIQUE AND APPLICATIONS
Authors: HAN P. Y. , CHO G. C. , ZHANG X.-C.
Published: March 2003

We present in this article the recent development of the measurement technique for coherent free-space THz field and applications in the mid-infrared range. The technique is based on the second-order nonlinear optical interaction both for the generation and for the detection of THz pulse. Particularly the detection process based on free-space electro-optic sampling gives us a possibility to timely trace directly the ultrabroad band coherent THz field unparalleled by other technique. Using an ultrashort laser pulse our measurement system is feasible to measure the ultrashort THz pulse with a bandwidth up to 40 THz. We present a detailed comparative study on the generation and detection using different nonlinear material. We demonstrate applications of the coherent THz technique for time-resolved semiconductor spectroscopy, time-domain imaging with high spatial resolution and broad band refractive and absorptive characterization of material in the mid-infrared range.
PHOTOREFRACTIVITY IN CROSSLINKED POLYMER-STABILIZED NEMATIC LIQUID CRYSTALS
Authors: WIEDERRECHT GARY P. , WASIELEWSKI MICHAEL R.
Published: March 2003

The observation of photorefractive gratings in new crosslinked polymer-stabilized liquid crystals (PSLCs) is discussed and compared to previous PSLCs. The PSLCs easily incorporate reduced or oxidized molecules that are present in a nematic liquid crystal at a concentration of 2 mol%. The PSLCs that are crosslinked provide improved photo-refractive grating resolution, due to their improved functionality as an immobile electron trap. These materials are capable of functioning well into the Bragg diffraction regime. Photoconductivity experiments that support the photorefractive mechanism and a different charge transport mechanism than neat liquid crystals are also performed.
A SIMPLE WAY TO SHOW THAT BRIGHT FEMTOSECOND SOLITONS CAN PROPAGATE IN BOTH DISPERSION REGIONS OF AN OPTICAL FIBER
Authors: PALACIOS S. L. , FERNÁNDEZ-DÍAZ J. M. , GUINEA A. , CRESPO R. D.
Published: March 2003

We solve by means of the coupled amplitude-phase formulation the derivative nonlinear Schrödinger equation (DNLS) for an optical fiber and we find fundamental soliton solutions in both the anomalous and normal dispersion regimes. Considering the general complex form of the solution it is very simple to see that bright solitons are also possible in the normal dispersion region.
STEADY STATE REPEATING OPTICAL PULSES IN A PERIODIC NONLINEAR FIBER
Authors: YARIV AMNON
Published: March 2003

We consider the self-consistent pulses which can propagate in a periodic fiber with alternating linear (β2≠0, n2=0) and nonlinear (β2=0, n2≠0) sections. The repeating breathing eigen pulse of the wave guide is derived.
CHIRAL MATERIALS IN SECOND-ORDER NONLINEAR OPTICS
Authors: KAURANEN MARTTI , VERBIEST THIERRY , PERSOONS ANDRÉ
Published: March 2003

We review how chirality can lead to new types of second-order nonlinear optical materials. Chiral molecules are noncentrosymmetric with a nonvanishing electric-dipole-allowed second-order response, which persists in macroscopic samples with high rotational symmetry such as isotropic solutions. On the other hand, contributions of magnetic-dipole interactions, which can be strong in chiral materials, allow second-order processes in centrosymmetric materials. The magnetic contributions of thin films of chiral polyisocyanides and polythiophenes are comparable to electric contributions. Components of the electric-dipole susceptibility tensor associated with chirality dominate the response of thin films of a chiral helicenebisquinone.
GUIDED-WAVE PHASE-MATCHING OF ULTRASHORT-PULSE LIGHT
Authors: DURFEE III C. G. , RUNDQUIST A. , BACKUS S. , CHANG Z. , HERNE C. , KAPTEYN H. C. , MURNANE M. M.
Published: March 2003

We review the use of hollow waveguides for frequency conversion of ultrafast laser pulses the ultraviolet and extreme ultraviolet. Phase-matching of these processes is reached through a balance of gas and waveguide dispersion. By mixing 400 nm with 800 nm light, ultrashort (8 fs) pulses are generated near 270 nm with high efficiency > 20%. Tuning of the longer-wavelength component in the mixing process allows tuning of the output from 215–308 nm. In the XUV, this guided-wave phase-matching has allowed an increase of conversion efficiency of high-order harmonic generation of 100–1000x over that obtained with a gas jet, in an experimentally-convenient geometry.
TRANSPORT INDUCED PATTERN SELECTION IN A NONLINEAR OPTICAL SYSTEM
Authors: RAMAZZA P. L. , BOCCALETTI S. , DUCCI S. , ARECCHI F. T.
Published: March 2003

The pattern selection process in a two-dimensional optical system, with a Kerr nonlinearity inserted in an optical feedback loop, is strongly affected by nonlocal interactions. Experimentally, nonlocality is introduced by means of a lateral transport of the feedback signal. As the transport length is increased, the system displays a sequence of transition over different classes of patterns. In the case of purely diffractive feedback, patterns corresponding to both focusing and defocusing nonlinearities are reported. When interference instead of diffraction operates in the feedback loop, new selection rules govern both the scale and the spatial symmetry of the observed structures. In all the cases considered, the stability analysis of the model equations yields theoretical predictions in good agreement with the experimental results.
MODELING AND SIMULATION OF NONLINEAR ELECTRON-HOLE PLASMA IN DEEP SUBMICRON N-MOSFET DEVICES
Authors: RAJENDRAN K. , GANESH S. SAMUDRA
Published: March 2003

Computer simulations were done extensively in order to study nonlinear dynamics of laser and non-equilibrium electron-hole plasma interaction in deep submicron n-MOSFET silicon devices. We constructed the modified Duffing kind of nonlinear electron-hole plasma oscillator equation. Nonlinear characteristics of electron-hole plasma by impact ionization in submicron devices manifest a wide diversity of complex chaotic behavior. Collision frequency is found to be the dominant parameter to influence the bifurcation, chaos, hysteresis and bistable effects of electron-hole plasma at deep submicron devices. Small windows of higher period cascade above the critical value of laser parameter (α1α2) in the chaos region are observed. Non-equilibrium electron-hole plasma shows much chaotic regime at lower value of laser frequency (δ). Hysteresis and bistable region of electron-hole plasma are also presented and the conditions for their occurrence are identified. The unstable region completely merge at higher value of effective collision frequency (γ).
ELECTRO-OPTICAL PHENOMENA DUE TO INFLUENCE OF LIGHT BEAMS ON MATERIAL PARAMETERS OF LIQUID CRYSTALS
Authors: TABIRYAN NELSON V. , UMETON CESARE
Published: March 2003

Modulation of material parameters of liquid crystals (LC) due to absorption of light beams allows to control the reorientation of the LC under the influence of ac electric fields. Particularly, it makes possible recording of photorefractive-like orientation gratings. Such gratings are phase shifted with respect to the pattern of interfering light beams. The material and external parameters determine the magnitude of the shift. These photorefractive-like phase shifted gratings are stationary, and no diffusion processes are involved in their build-up.
SECOND-ORDER NONLINEAR OPTICAL POLYIMIDES WITH HIGH THERMAL STABILITY
Authors: ZHU PEIWANG , WANG PENG , WU WEI , YE CHENG
Published: March 2003

Two high Tg (250°C and 258°C) polyimides embedded with triphenyl imidazole chromophores were synthesized through addition polymerization. Simultaneous poling and polymerization and in situ second harmonic generation measurement technology were carried on to evaluate the thermal stability of the poling induced orientations. Moderate d33 values of 15 pm/V and 16 pm/V were determined. The SHG signals of these poled polymer films are without any decay at temperature lower than 150°C, it begins to relax rapidly over 195°C. The half-decay temperatures of the samples' orientation are as high as 240°C and 24°C respectively.
SOLITON DYNAMICS IN TWO WAVEGUIDES WITH DISPERSION PROPERTIES OF THE LINEAR COUPLING COEFFICIENT
Authors: KAMBUROVA R. S. , PRIMATAROWA M. T.
Published: March 2003

The soliton dynamics in two parallel waveguides is investigated numerically with the dispersion of the linear coupling coefficient taken into account. It is shown that the new terms in the system of coupled nonlinear equations which describe the switching process have an important influence on the soliton propagation for short pulses in directional couplers. In this case, depending on the value of the coupling-coefficient dispersion, an effect of distorsion or breakup of the initial pulse can be observed.
SOLITON–SOLITON INTERACTION IN OPTICAL FIBERS
Authors: BISWAS ANJAN
Published: March 2003

In an optical communication system it is necessary to place the solitons close to one another to increase the information carrying capacity of the fiber. The theory of soliton–soliton interaction in a fiber optic communication system, through a single channel, is studied in this paper. In presence of the perturbation terms, the two soliton interaction of the Nonlinear Schrödinger's Equation is investigated. It is analytically proved and numerically supported that the perturbation terms lead to the suppression of the interaction of solitons through an optical fiber.
SUPPRESSION OF SOLITON INSTABILITY BY HIGHER ORDER NONLINEARITY IN LONG HAUL OPTICAL COMMUNICATION SYSTEMS
Authors: KONAR S. , KUMAR J. , SEN P. K.
Published: March 2003

The results of the numerical simulation of the propagation characteristics of periodically amplified solitons in a long nonlinear fiber have been reported. The roles played by both Kerr and saturable nonlinearities have been examined. The possibility of occurrence of instability and loss of solitons are also explored. This instability is found to be sensitive to the initial chirp, fiber loss rate and amplifier spacing. Symmetrical splitting of solitons is also reported. The inhibition of instability and splitting can be possible through saturable optical nonlinearity.
SURFACE PLASMON ENHANCED OPTICAL SECOND HARMONIC GENERATION IN ULTRA-THIN METALLIC FILMS
Authors: LUE JUH-TZENG , CHANG CHIA-SHY
Published: March 2003

Internal reflection of second-harmonic generations from silver films with thickness ranging from 5 nm to 50 nm are enhanced by the excitation of surface plasmons under Kretschmann configuration. Enhancement of the SHG was observed at a film thickness of 20 nm resulting from the field enhancement of granular structure. For thinner films, the surface reveals disconnected islands as inspected by the atomic force microscopy. The incident angular position to find the peak intensity and the change of linewidth of the SHG can almost satisfactorily be predicted by the theory based on surface scattering.
AN EASY APPROACH FOR ESTIMATING ABSORPTION LOSS IN ORGANIC THIN SOLID FILMS
Authors: YUQUAN SHEN , ZHAO LI , YUXIA ZHAO , JIANFENG ZHAI , JIAYUN ZHOU , LING QIU , JIANHONE WANG , YINGLI CHEN , ZHUANGQI CHAO , PUN EDWIN Y. B. , CHUNG PO S.
Published: March 2003

An UV-VIS-Near-IR spectroscopic method for determination of optical loss in organic/polymeric films has been suggested. The optical losses of two polyimide polymers with push-pull azobenzene chromophore attached were examined by this method and the data were calibrated by conventional optical method.
THE CHIARI PELVIC OSTEOTOMY
Authors: Ok I. Y. , Jeong C. H. , Lee H. Y.
Published: March 2003

The result of 27 Chiari pelvic osteotomy were analyzed to determine the efficacy of the operation in the treatment of subluxated and/or painful dysplastic hips. The length of follow-up ranged from 2 to 14 years. Eighteen patients had had developmental dysplasia of the hip; four sequelae of the septic hip; two, cerebral palsy and one had had poliomyelitis. The osteotomy can be done by power saw and osteotome. A large threaded K-wire was used for internal fixation. Bone graft was necessary even with the displacement of more than 50%. The overall result were: 12, excellent; 8, good; 5, fair; and 2 poor. In 11 patients, the osteotomy had to be displaced more than 50% to provide good coverage of the femoral head. There were no major complications such as sciatic nerve injury or delayed union. This procedure is most suited for the patient with painful hip dysplasia in whom a concentric reduction is not possible.
PAVLIK HARNESS IN THE TREATMENT OF DEVELOPMENTAL DYSPLASIA OF THE HIP — A CLINICAL AND ULTRASONOGRAPHIC STUDY
Authors: Cheng J. C. Y.
Published: March 2003

Eighty cases of early DDH treated with Pavlik harness over a 10-year period in one centre was followed up for a minimum of 2 years with a mean of 6.5 years. Sixty-five percent of the patients presented to the clinic before the age of 4 weeks, and 10% after 12 weeks. Sixty percent presented clinically as dislocated reducible hip, 25% as dislocated non-reducible hip, and 15% as dislocatable hip. Static and dynamic ultrasonographic grading revealed 65% as pathological hip and 35% as normal. Clinical and ultrasonographic assessment revealed that 2 weeks after commencement of the Pavlik Harness treatment, 78% of the hips were reduced and this increased after 4 weeks, to 91.2%. The most significant factors affecting the outcome were the age at the start of treatment and the clinical type of hip. A 95% success reduction rate was achieved for those treated before the age of 8 weeks and only 50% for those after this age. Ninety-five percent of the dislocated reducible hips and 100% of the dislocatable hips were successfully reduced. Of the initial dislocated irreducible hips, only 50% were successfully reduced. At the final follow-up, the clinical and radiological assessment showed an overall success rate of 84%. Avascular necrosis was only found in 1 case (1.25%).
SCREENING FOR NEONATAL HIP INSTABILITY IN AN ASIAN POPULATION: AN EVALUATION OF THE FIRST 5 YEARS
Authors: Ang K. C. , Lee E. H.
Published: March 2003

Developmental dysplasia of the hip can result in significant morbidity both in childhood and later in adult life. Early diagnosis enables better results to be obtained with fewer complications, while delayed diagnosis can lead to prolonged treatment with less satisfactory outcome.

A Neonatal Hip Screening program for DDH has been in place in the National University Hospital, Singapore since December 1989. Our program is run by consultant neonatologists and consultant paediatric orthopaedic surgeons. All neonates seen with DDH are followed up for a minimum of 1 year with ultrasonography and X-rays.

Our results show an incidence of dislocated hips of 4.7 per 1000 live births. The incidence of neonates with acetabular dysplasia as defined by an Acetabular Index of > 30° is 16.8 per 1000 live births.

The early diagnosis and treatment of hip dislocation is important for the development of a normal acetabulum. Neonatal Hip Screening programs have been shown to be effective in the early diagnosis, resulting in successful outcome of treatment and reduction of economic costs in the management of DDH.

The finding of a significant incidence of DDH in our population and the successful management after early diagnosis in our study have vindicated the establishment of our hip screening program.
TREATMENT OF FLEXION INSTABILITY OF LUMBAR SPINE WITH GRAF BAND
Authors: Moon Myung-Sang , Moon Young-Wan , Moon Jeong-Lim , Kim Sung-Sim , Shim Yong-Shik
Published: March 2003

This study focused mainly on the long-lasting effectiveness of Graf band stabilization system on the stabilized lumbar motion segment together with the band fate and the final outcome. Graf soft stabilization operation was carried out to suppress the forward flexion and rotatory instability. Fifty-one patients were subjected to this study. Forty-five had pure forward flexion instability preoperatively. Among the 51 patients, 20 were irreducible mild spondylolisthesis and 8 reducible mild spondylolisthesis; 17 excessive flexion angular motion; one disc disease with mild stenotic symptoms; and 5 post-laminectomy instability.

In this series, good or excellent results were obtained in 40 cases (78.7%); fair in 4; no improvement in 4; and poor in 3. JOA lumbar score increased from 16 at preoperative exam to 26.5 on average at the final examination. In 3 cases screws were malpositioned. In 2 cases, mild transient drop foot developed, and spontaneous fusion occurred in one disc surgery patient. There was no implant loosening or breakage, and no overstretch and tear of bands or disengagement. There was no recurrence of segmental instability at the immobilized segment. Also, there were no adjacent joint problems.

In summary, the Graf procedure appears to be a good alternative to spinal fusion for the stabilization of the unstable segment with forward flexion instability.
GAIT ANALYSIS THROUGH FOOT PATTERN RECOGNITION FOR CHILDREN WITH CEREBRAL PALSY
Authors: Wong Alice M. K. , Chen Chia-Ling , Hong Wei-Hsien , Chiou Wen-Ko , Chen Hsieh-Ching , Tang Fuk-Tan
Published: March 2003

In this study, we simplified the analysis of kinetic gait data using pattern recognition. Gait patterns were studied in 42 spastic children with cerebral palsy (age range: 3 to 17 years old), and 24 age- and sex-matched children. Gait analysis was performed using the DynoGraphy (CDG) system (Infortronic, Holland). The foot enrollment and the role of the heel or forefoot were assessed to form the gaitline. The bipedal phase was examined using a cyclogram, which is a cyclic characteristic formed by the changing position of the application point of the resultant normal force on a vertical supporting horizontal plane during motion. Based on the pattern recognition, the gait patterns of the subjects could be classified into 4 different patterns in both the gaitline and the cyclogram. The classification of the gait was parallel to the clinical evaluation of cerebral palsy obtained based on Minear's classification of daily activity (p<0.05). The correlation between the gaitline and cyclogram was also highly significant (p<0.05). The results of this study suggest that an automated pattern recognition program might provide an additional method for comprehensive gait evaluation in children with cerebral palsy.
A SURFACE EMG DRIVEN MUSCULOSKELETAL MODEL OF THE ELBOW FLEXION-EXTENSION MOVEMENT IN NORMAL SUBJECTS AND IN SUBJECTS WITH SPASTICITY
Authors: Feng Connie J. , Mak Arthur F. T. , Koo Terry K. K.
Published: March 2003

Spasticity often interferes with function, limits independence and may cause considerable disability. Elbow joint movement is involved in many daily living activities. A surface EMG driven musculoskeletal model was developed to predict joint trajectory and to compare the differences in the model parameters between the normal and spastic subjects. Three musculotendon actuators whose EMG could be assessed by surface electrodes (biceps, brachioradialis and triceps) were included in this musculoskeletal model. The proposed model took several sets of parameters (anthropometric parameters of the skeleton and muscle parameters) as inputs. Surface EMG signals of the three muscle groups were rectified, moving-averaged, scaled and converted to active states. These active states together with the initial angular position and velocity of the joint were also used as inputs for the model. The outputs were muscle forces and the trajectory of the elbow joint. Two groups of parameters, namely, maximal isometric muscle stress and electromechanical delay were estimated using the trajectory fitting algorithm. Results indicated that the model was successful in using the surface EMG as input signals in the prediction of elbow joint trajectory. The spastic subjects showed a lower maximum isometric muscle stress and longer electromechanical delay.
EFFECT OF INSTRUMENTED LUMBAR FUSION ON THE FLEXIBILITY AND VISCOELASTIC PROPERTIES OF THE ADJACENT SEGMENT: AN IN VIVO CANINE STUDY
Authors: Lim Tae-Hong , Patwardhan Avinash G. , Hong Jung Hwa , An Howard S. , Riley Lee H. , Hodges Scott D. , Zindrick Michael M.
Published: March 2003

The altered mechanical environment due to a rigid fixation is considered as the cause of degeneration at the adjacent levels. A canine in vivo study was performed to investigate the long-term effects of spinal fusion with instrumentation across the L5-sacrum on the flexibility and viscoelastic properties of the adjacent L4–5 disc. Five experimental dogs underwent a posterior fusion with Isola transpedicular instrumentation from L5 to sacrum and were euthanized 30 weeks postoperatively. A solid fusion was achieved across L5–L7 levels, but substantial motion persisted at the L7-sacrum segment. Biomechanical tests were performed to measure the flexibility and viscoelastic properties of the intervertebral disc above the instrumented spinal fusion in the experimental and nonoperated control groups. No statistically significant differences in the flexibility and viscoelastic responses of the adjacent L4–L5 segment were found between the control and experimental groups. Fusion of the L5–L7 segments did not significantly affect the flexibility and viscoelastic properties of the L4–5 disc at 30 weeks postoperatively in the mongrel dog spine.
SOFT STABILIZATION OF THE LUMBAR SPINE USING THE GRAF SYSTEM FOR SPINAL INSTABILITY SYNDROMES AND PSEUDOARTHROSIS — 5 YEARS' RESULTS
Authors: Leeks N. , Skinner I. , Hardcastle P.
Published: March 2003

There is considerable controversy in the diagnosis and management of lumbar spinal instability. Most clinicians agree that patients suffering from the chronic low back syndrome who have suspected instability and have not responded to conservative measures, should be considered for operative treatment with stabilization using rigid or semi-rigid systems to reduce or eliminate movement at the painful segment.

The concept of soft stabilization was introduced by Henri Graf in 1988 and has become a routine procedure in various centres throughout the world for stabilization for clinical instability syndromes.

The Graf system was introduced into Western Australia in October, 1991. The aim of this paper is to report the independently reviewed retrospective results of the first 25 patients with respect to clinical outcome and radiological features.

The clinical outcomes were consistent with other reported treatment measures for the chronic low back pain syndrome. The radiological results do not show any evidence of implant loosening or breakage.
CLINICAL, ELECTROPHYSIOLOGICAL, AND HISTOPATHOLOGIC STUDIES IN HEREDITARY MOTOR AND SENSORY NEUROPATHY V: ONE CASE REPORT
Authors: Bai Yue-Hong , Tokuhiro Akira , Takemitsu Masakazu , Atsuta Yuji , Cho Kazuhiko , Matsuno Takeo
Published: March 2003

Hereditary motor and sensory neuropathy type V (HMSN V) is a rare disorder characterized by the clinical features of spastic paraplegia with peroneal muscular atrophy. A patient with progressive deformity of the feet due to HMSN V underwent clinical, electrophysiological, histopathological examinations, and surgical treatments. Physical examination revealed bilateral pes equinovarus and peroneal muscular atrophy with pyramidal tract features. In the lower limbs, motor nerve conduction velocity could not be determined, and sensory nerve conduction velocity was decreased. In contrast, the results of both the conduction studies were normal for the upper limbs. A sural nerve biopsy revealed a decrease in the number of myelinated fibers and in the diameter of the unmyelinated fibers, and axonal and myelin regeneration was found on light and electron microscopic examinations, suggesting an axonopathy. Since the patient had pyramidal tract features, the same pathological changes may be present in the spinal cord. In the surgical treatment to correct deformity of the feet in this patient, triple arthrodesis was necessary.
THE ARCHITECTURE OF COLLAGENS IN OSTEOPHYTES: A STUDY BY IMMUNOHISTOCHEMISTRY
Authors: Alonge T. O. , Rooney P. , Oni O. O. A.
Published: March 2003

The collagen architecture of osteophytes has been investigated by immunolocalization of types I, II, III and X collagens. Types I and III were observed in the superficial layers, type II in the superficial and middle layers and type X at the cartilage-bone junction. This pattern of distribution suggests a "maturation" pathway from precursor cells at the surface to cells transforming into bone at the base. The collagen fibers appear to be oriented horizontally in the superficial layers and vertically in the middle or intermediate layers, thus mimicking the architectural arrangement in normal articular cartilage.
LIGAMENT LENGTH DURING CIRCUMDUCTION OF THE TRAPEZIOMETACARPAL JOINT AFTER LIGAMENT SECTIONING
Authors: Imaeda Toshihiko , Niebur Glen , Cooney William P. , Linscheid Ronald L. , An Kai-Nan
Published: March 2003

Thumb motion and stability were examined after sequential division of support ligaments of the trapeziometacarpal (TMC) to simulate the pathologic condition of ligament laxity. The motion obtained with passive circumduction was measured with a magnetic tracking system. The lengths of the TMC joint ligaments were approximated by measuring the distance between origin and insertion of each ligament. The change in this apparent interorigin distance of the ligaments was measured before and after ligament sectioning. The anterior oblique ligament (AOL) and the ulnar collateral ligament (UCL) had the greatest effect on TMC joint stability during circumduction of the thumb. Division of the first intermetacarpal ligament (IML) did not produce a change in apparent length of other ligaments. We conclude that small changes in ligament length affect thumb stability and alter the path of circumduction. Neither the IML or posterior oblique ligaments were major stabilizers of the TMC joint during circumduction, prehensile grasp, or tip pinch. Reconstruction of the AOL and UCL ligaments should be considered for treatment of the initial stages of TMC instability.