Multilayer power printed structures suitable for controlling EMI noises generated in power converters

Electromagnetic interference (EMI) noises generated in power converters are diffused on the surface of conductors. This means influences occur from radiated EMI noises emitted from power transmission lines as well as conducted EMI noises transmitted from them. EMI noises diffusing on the surface of conductors are generally difficult to control using conventional concentrated constant theory. Thus, a new approach based on distributed constant circuit theory is needed in order to control EMI noises. A power converter structure to control EMI noises using multilayer power printed circuit technology is studied in this paper. A structure which can control EMI noises should simultaneously satisfy two conditions, i.e., one to shut down and one to attenuate EMI noises. The structure satisfying these conditions is studied through simulations using the Transmission-Line Modeling Method. The simulations show that the diffusion of EMI noises is controlled by dividing the flow of currents produced by EMI noises into the horizontal and perpendicular directions. That is, the horizontal current flow is controlled inside using the differences in the resistance produced from differences between inner and outer diameter of power transmission lines and the perpendicular current flow can be controlled by properly designing the thickness of the dielectric layer sandwiched between P-and N-power transmission lines with the symmetrical structure. Moreover, it is confirmed by simulations and experiments that the attenuation of EMI noises is affected by the width of the power transmission lines. It is expected that the results obtained in this paper can provide important rules when designing power converters with EMI noise control functions which use the multilayer power printed circuit technology.     

Auditory middle latency responses in patients with epilepsy

Middle latency auditory responses (MLRs) were studied in 55 normal subjects and 49 epileptic patients. We evaluated the function of the auditory system and of the temporal lobe in epileptic patients using MLRs. (1) The patients with epilepsy had significantly prolonged Pa and Nb latencies and the significantly increased amplitude of Pa-Nb component. (2) The prolongation and the increase of MLR components in latency and amplitude were more obvious in patients with intractable epilepsy than patients without intractable epilepsy. (3) The difference between left and right sides was larger in epileptic patients than normal subjects. (4) Epileptic patients with polypharmacy had reduced amplitude of Pa-Nb component and prolonged latency of Pa component than patients with monotherapy. Antiepileptic drugs (AEDs) appeared to decrease the amplitude of Pa-Nb component. It was supposed that the enhancement of amplitude of Pa-Nb component represented the abnormality of central nerve system in epileptic patients, in part.     

Characterization of a cartilage-derived 66-kDa protein (RGD-CAP/beta ig-h3) that binds to collagen

Malignant human gliomas are the most common forms of primary tumors in the central nerve system. Due to their location and invasive nature, treatment so far has been mainly palliative. Thus, understanding the molecular detail of tumor transformation and progression is crucial for developing effective therapeutic strategy for this fetal tumor. Among the genetic alternations found in these tumors, p53 inactivation and PDGF/PDGFR activation represent the early events, and the loss of chromosome 10 and gene amplification and rearrangement of EGFR represent the late events. Studies with both glioma cell lines and primary tumor tissues have strongly suggested that TGF-alpha and EGFR function as an important autocrine loop in supporting proliferation of human glioma, especially in high grade glioma, since elevated TGF-alpha expression is also found in these high grade tumors. Furthermore, down regulation of the expression of TGF-alpha by antisense constructs has been shown to inhibit several types of human tumor cell growth including glioma. Other means of therapeutic approaches using this autocrine loop as a target also include the use of monoclonal antibodies and their cytotoxic conjugated. Considerable understanding of the EGFR-mediated signal transduction pathways has become available recently, which including GRB2/mSOS1 mediated MAP kinase activation; JAK/STATs pathway; PLC-gamma pathway. However, much work still needs to be done before a specific component of these pathways can be applied for effective control of tumor growth in the clinic.     

The temperature dependence of luminescence from a long-lasting phosphor exposed to ionizing radiation

The temperature dependence of luminescence from a long-lasting phosphor (LLP), SrAl₂O₄ : Eu²⁺,Dy³⁺, exposed to ionizing radiation has been measured to understand the LLP luminescence mechanism. Evaluation of the decay constants of the LLP exposed to -, β- or γ-rays at temperatures from 200 to 390 K showed that the decay constant is divided into four components ranging from 10⁻⁴ to 10⁻¹ s⁻¹ with activation energies of 0.02–0.35 eV.

Total luminous intensity from the LLP with changing irradiation temperature has its maximum value around the room temperature. Irradiation at elevated temperature (390 K) has the total luminescence pattern with monotonous decrease as temperature rises. As a result of evaluating the temperature dependence of luminescence, the luminescence mechanism is considered as follows:

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Effects of some calcium-related agents on the protoplast transfection of Lactobacillus casei with phage PL-1 DNA

An audit of the treatment procedures routinely adopted by maxillofacial and oral surgeons for the removal of impacted third molars under general anaesthesia was undertaken in South Africa. Most maxillofacial and oral surgeons agree on the method of bone removal, the prescribing of antibiotics, analgesic agents and mouthwashes, the suturing of the incision wound and the post-operative review of patients. The results were compared to a similar study undertaken by Falcon and Roberts (1992) in the UK. With the exception of the method of bone removal, maxillofacial and oral surgeons in both groups share a similar approach to the treatment procedures adopted in the removal of impacted third molars. Some variability, however, existed in both studies with regard to the use of intra-operative local anaesthetic agents, the administration of peri-operative steroids and the use of non-steroidal anti-inflammatory agents.     

Extensions of polyacrylic acid ammonium salts in the adsorption layer to fluidize alumina slurries

An average shell volume occupied in the adsorption layer on alumina by a polyacrylic acid ammonium salts molecule (PAA) defined as the average area occupied by an adsorbed PAA on alumina multiplied by the average thickness of the water layer at the limit of thickening, has been calculated from the adsorbed amount of PAA and from the flow points of alumina in the presence of PAA of different molecular weights. A steric effect of the PAA dispersant on the dispersion of alumina resulted in a flow with no yield stress. This was due to the change of the extension of PAA in the adsorption shell from a sphere to an ellipsoid with a long axis which exceeded the effective distance that the van der Waals attraction force reaches at a molecular weight for the PAA of between 10 000–20 000.     

Effect of ibudilast on microcirculation thrombosis in rat inner ear

Arterial wall thickening may be quantitatively assessed by measuring the intima-media thickness (IMT) with high resolution ultrasound. Previous studies have shown a good inter/intraobserver variability of IMT measurements in the common carotid. In this study we evaluated the inter/intraobserver variability of IMT measurements in 10 randomly selected asymptomatic subjects (age 55.4 +/- 6). Two carotids and two femorals were studied in each subject. IMT for each patient was the average of five IMT measurements at the artery bifurcation. Three observers repeated the scanning and the measurements twice with no knowledge of the previous readings. The between observer coefficient of variation (CV) was 8.45%; the intraobserver CV (mean of carotids and femorals) varied from 4.4 to 5.1% for the three observers who measured IMT three times. The mean absolute difference between the first and the third measurement was 0.0738 mm. In conclusion IMT measurement variability is mostly due to differences between observers. The intraobserver variability is very small. IMT measurements at the carotid and femoral bifurcations have a low variability and are a good expression of atherosclerosis as they consider early lesions at the bifurcation level which may not be observed in the common carotid.     

Sociodemographic factors and the variation in syphilis rates among US counties, 1984 through 1993: an ecological analysis

OBJECTIVES: Syphilis in the United States is focally distributed, with high incidence rates in the South and in metropolitan areas nationwide. In this study an ecological analysis, using the county as the unit of analysis, was performed to generate hypotheses about community-level determinants of syphilis rates. METHODS: Bivariate rank correlations and multivariate, backward stepwise elimination linear regressions were performed. Mean annual incidence of primary- and secondary-stage syphilis in a county was the dependent variable, and county sociodemographic characteristics (from census data) were the independent variables. RESULTS: In the multivariate regression model, sociodemographic characteristics accounted for 71% of the variation in syphilis rates among counties. With other factors accounted for, the most highly correlated characteristics were percentage non-Hispanic Black population, county location in the South, percentage of the population that was urban, percentage Hispanic population, and percentage of births to women younger than 20 years. CONCLUSIONS: Most of the variation in syphilis rates among counties is accounted for by sociodemographic characteristics. Identification and remediation of modifiable health determinants for which these factors are markers are needed to improve the health status of these populations.     

Neutral poly(3,4-ethylenedioxythiophene-2,5-diyl)s: preparation by organometallic polycondensation and their unique p-doping behavior

Neutral and non-doped poly(3,4-ethylenedioxythiophene), PEDOTh(Ni), and its hexyl derivative, PEDOTh-C₆(Ni), have been prepared by organometallic dehalogenation polycondensation of 2,5-dichloro-3,4-ethylenedioxythiophene and its hexyl derivative with a zerovalent nickel complex. PEDOTh-C₆(Ni) was soluble in organic solvents and ¹H NMR data indicated that it had an M_n of 11,000. MALDI-TOF mass analysis of PEDOTh(Ni) gave M_n and M_w of about 1700 and 2400, respectively. PEDOTh-C₆(Ni) showed a UV-Vis absorption peak at 546 nm in CHCl₃. Electrochemical oxidation of PEDOTh-C₆(Ni) started at about −0.40 V vs Ag⁺/Ag and gave a peak at 0.20 V vs Ag⁺/Ag. Chemical and electrochemical oxidation (or p-doping) of PEDOTh-C₆(Ni), both in solutions and in a solid state, led to weakening of the original π-π^∗ peaks and rise of new peak(s) in a region of 800-1500 nm. The p-doping of PEDOTh-C₆(Ni) caused not only a decrease in the intensity of ¹H NMR signals of the bridging ethylene hydrogens but also a decrease in that of the hexyl side chain, suggesting a strong interaction of the p-dopant with the side chain. NMR data of poly(3-methoxythiophene-2,5-diyl) also supported an assumption that p-doping brings about a severe change in electronic state of the substituent attached to the polythiophene main chain. PEDOTh(Ni) had a density of 1.71 g cm⁻³; the molecular packing mode of PEDOTh(Ni) is discussed based on the density of the polymer and its XRD data.