Showing papers by "Sungkyunkwan University published in 1999"

Differences in nature of defects between SrBi2Ta2O9 and Bi4Ti3O12

Abstract: X-ray photoemission spectroscopy measurements were executed to compare the nature of defects in SrBi2Ta2O9 (SBT) and Bi4Ti3O12 (BTO) films. In the SBT film, it was found that the oxygen ions at the metal–oxygen octahedra were much more stable than those at the Bi2O2 layers. On the other hand, for the BTO film, oxygen vacancies could be induced both at the titanium–oxygen octahedra and at the Bi2O2 layers. We suggested that the difference in stability of the metal–oxygen octahedra should be related to different fatigue behaviors of the SBT and the BTO films.

Antioxidative flavonoids from the leaves of Morus alba.

Abstract: Nine flavonoids (1-9) were isolated from the leaves of Morus alba (Moraceae). The structures of compounds were determined to be kaempferol-3-O-beta-D-glucopyranoside (astragalin, 1) kaempferol-3-O-(6"-O-acetyl)-beta-D-glucopyranoside (2), quercetin-3-O-(6"-O-acetyl)-beta-D-glucopyranoside (3), quercetin-3-O-beta-D-glucopyranoside (4), kaempferol-3-O-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranoside (5), quercetin-3-O-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranoside (rutin, 6), quercetin-3-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside (7), quercetin-3,7-di-O-beta-D-glucopyranoside (8) and quercetin (9) on the basis of spectroscopic and chemical studies. Compounds 7 and 9 exhibited significant radical scavenging effect on 1,1-diphenyl-2-picrylhydrazyl radical.

In vitro chemopreventive effects of plant polysaccharides (Aloe barbadensis miller, Lentinus edodes, Ganoderma lucidum and Coriolus versicolor).

Abstract: A plant polysaccharide, Aloe gel extract, was reported to have an inhibitory effect on benzo[a]pyrene (B[a]P)-DNA adduct formation in vitro and in vivo. Hence, chemopreventive effects of plant polysaccharides [Aloe barbadensis Miller (APS), Lentinus edodes (LPS), Ganoderma lucidum (GPS) and Coriolus versicolor (CPS)] were compared using in vitro short-term screening methods associated with both initiation and promotion processes in carcinogenesis. In B[a]P-DNA adduct formation, APS (180 micrograms/ml) was the most effective in inhibition of B[a]P binding to DNA in mouse liver cells. Oxidative DNA damage (by 8-hydroxydeoxyguanosine) was significantly decreased by APS (180 micrograms/ml) and CPS (180 micrograms/ml). In induction of glutathione S-transferase activity, GPS was found to be the most effective among plant polysaccharides. In screening anti-tumor promoting effects, APS (180 micrograms/ml) significantly inhibited phorbol myristic acetate (PMA)-induced ornithine decarboxylase activity in Balb/3T3 cells. In addition, APS significantly inhibited PMA-induced tyrosine kinase activity in human leukemic cells. APS and CPS significantly inhibited superoxide anion formation. These results suggest that some plant polysaccharides produced both anti-genotoxic and anti-tumor promoting activities in in vitro models and, therefore, might be considered as potential agents for cancer chemoprevention.

An activator binding module of yeast RNA polymerase II holoenzyme

Abstract: The Mediator complex of Saccharomyces cerevisiae is required for both general and regulated transcription of RNA polymerase II (PolII) and is composed of two stable subcomplexes (Srb4 and Rgr1 subcomplexes). To decipher the function of each Mediator subcomplex and to delineate the functional relationship between the subcomplexes, we characterized the compositions and biochemical activities of PolII-Mediator complexes (holoenzymes) prepared from several Mediator mutant strains of S. cerevisiae. We found that holoenzymes devoid of a functional Gal11 module were defective for activated but not basal transcription in a reconstituted in vitro system. This activation-specific defect was correlated with a crippled physical interaction to transcriptional activator proteins, which could be bypassed by artificial recruitment of a mutant holoenzyme to a promoter. Consistent with this observation, a direct interaction between Gal11 and gene-specific transcriptional activator proteins was detected by far-Western analyses and column binding assays. In contrast, the srb5 deletion mutant holoenzyme was defective for both basal and activated transcription, despite its capacity for activator binding that is comparable to that of the wild-type holoenzyme. These results demonstrate that the Gal11 module of the Rgr1 subcomplex is required for the efficient recruitment of PolII holoenzyme to a promoter via activator-specific interactions, while the Srb4 subcomplex functions in the modulation of general polymerase activity.

Lacrimal gland HGF, KGF, and EGF mRNA levels increase after corneal epithelial wounding.

Abstract: Purpose To evaluate the effect of corneal epithelial wounding on lacrimal gland expression of hepatocyte growth factor (HGF), keratinocyte growth factor (KGF), and epidermal growth factor (EGF) in the rabbit model. Methods Rabbits had corneal epithelial scrape injuries, and the lacrimal gland was removed at different times after wounding. HGF, KGF, and EGF mRNA expression was examined by quantitative RNase protection assay. HGF, KGF, and EGF proteins were detected in rabbit lacrimal tissue using immunoprecipitation and western blot analysis. Results HGF mRNA and EGF mRNA were significantly increased in rabbit lacrimal gland tissue within 8 hours after corneal epithelial injury. The increase in KGF mRNA expression was small and reached significance I clay after corneal injury. Lacrimal gland expression peaked at 3 days after wounding for each growth factor mRNA, the same day, on average, that the epithelial defect healed. After the peak increase in expression, there was a progressive decline in expression of each growth factor mRNA, but production was still increased compared with prewound levels. HGF protein, KGF protein, and EGF proteins were detected in rabbit lacrimal gland tissue. Conclusions Levels of HGF, KGF, and EGF mRNAs increase in rabbit lacrimal gland tissue in response to corneal epithelial wounding. The results of this study are consistent with the existence of a cornea-nervous system-lacrimal gland regulatory loop modulating expression of these growth factor mRNAs. The lacrimal gland is a likely source of increased HGF and EGF proteins detected in tears in previous studies.

Decision fusion approach for multitemporal classification

Abstract: This paper proposes two decision fusion-based multitemporal classifiers, namely, the jointly likelihood and the weighted majority fusion classifiers, that are derived using two different definitions of the minimum expected cost. Without any overhead incurred by multitemporal processing, a user-selected conventional pixelwise classifier makes local class separately using each temporal data set, and the multitemporal classifiers make the global class decisions by optimally summarizing those local class decisions. The proposed weighted majority decision fusion classifier can handle not only the data set reliabilities but also the classwise reliabilities of each data set. Classification experiment using the jointly likelihood decision fusion with three remotely sensed Thematic Mapper (TM) data sets shows more than 10% overall classification accuracy improvement over the pixelwise maximum likelihood classifier.

TNF-α-Mediated Apoptosis Is Initiated in Caveolae-Like Domains

Abstract: Caveolae-like domains (CLDs) have been hypothesized to mediate apoptosis, since they contain sphingomyelin and initiate the conversion of sphingomyelin to ceramide. To address whether CLDs are directly involved in apoptosis, CLDs from U937 cells were isolated, taking advantage of their detergent insolubility and low density. The CLDs contained alkaline phosphatase as well as many signaling molecules, including Fyn, protein kinase Calpha, Raf-1, phospholipase Cgamma1, and tyrosine phosphoproteins. Immunoblotting and immunofluorescent data showed that TNF receptor 1 colocalized with CD36 in CLDs, suggesting that TNF-alpha-initiated apoptosis occurs in CLDs. When cells were incubated with lipoprotein-deficient medium, the cholesterol concentration was greatly decreased in CLDs but not in other fractions, implying that the CLDs were selectively disrupted. In the CLD-disrupted cells, the surface expression of TNF receptor 1 and CD36 was significantly reduced. Analysis of cellular morphology, percent DNA fragmentation, DNA laddering, and caspase-3 activity showed that TNF-alpha-mediated apoptosis was blocked in CLD-disrupted cells, whereas anti-Fas-mediated apoptosis was not. Since Fas was not found in CLDs of Jurkat cells, apoptosis by Fas ligation might not require CLDs. Taken together, these data strongly imply that TNF-alpha-mediated apoptosis is initiated in CLDs.

Genetic dissection of protein-protein interactions in multi-trna synthetase complex

Abstract: Cytoplasmic aminoacyl-tRNA synthetases of higher eukaryotes acquired extra peptides in the course of their evolution. It has been thought that these appendices are related to the occurrence of the multiprotein complex consisting of at least eight different tRNA synthetase polypeptides. This complex is believed to be a signature feature of metazoans. In this study, we used multiple sequence alignments to infer the locations of the peptide appendices from human cytoplasmic tRNA synthetases found in the multisynthetase complex. The selected peptide appendices ranged from 22 aa of aspartyl-tRNA synthetase to 267 aa of methionyl-tRNA synthetase. We then made genetic constructions to investigate interactions between all 64 combinations of these peptides that were individually fused to nonsynthetase test proteins. The analyses identified 11 (10 heterologous and 1 homologous) interactions. The six peptide-dependent interactions paralleled what had been detected by crosslinking methods applied to the isolated multisynthetase complex. Thus, small peptide appendices seem to link together different synthetases into a complex. In addition, five interacting pairs that had not been detected previously were suggested from the observed peptide-dependent complexes.

Granulomatous mastitis: Mammographic and sonographic appearances

Abstract: OBJECTIVE: The objective of our study is to describe the mammographic and sonographic appearances of granulomatous mastitis. CONCLUSION: Granulomatous mastitis can mimic breast carcinoma clinically and mammographically, but the sonographic appearance of multiple clustered, often contiguous tubular hypoechoic lesions that are sometimes associated with a large hypoechoic mass should suggest the possibility of granulomatous mastitis.

Thermoreversible gelation of poly(ethylene oxide) biodegradable polyester block copolymers. II

Abstract: Poly(ethylene oxide)-b-poly(L-lactic acid) (PEO-PLLA) diblock copolymers were synthesized via a ring opening polymerization from poly(ethylene oxide) and L-lactide. Stannous octoate was used as a catalyst in a solution polymerization with toluene as the solvent. Their physicochemical properties were investigated by using infrared spectroscopy, 1 H-NMR spectroscopy, gel permeation chromatography, and differential scanning calorimetry, as well as the observational data of gel-sol transitions in aqueous solutions. Aqueous solutions of PEO-PLLA diblock copolymers changed from a gel phase to a sol phase with increasing temperature when their polymer concentra- tions are above a critical gel concentration. As the PLLA block length increased, the gel-sol transition temperature increased. For comparison, diblock copolymers of poly- (ethylene oxide)-b-poly(L-lactic acid-co-glycolic acid) (PEO-P(LLA/GA)) and poly(ethyl- ene oxide)-b-poly(DL-lactic acid-co-glycolic acid) (PEO-P(DLLA/GA)) were synthesized by the same methods, and their gel-sol transition behaviors were also investigated. The gel-sol transition properties of these diblock copolymers are influenced by the hydro- philic/hydrophobic balance of the copolymer, block length, hydrophobicity, and stereo- regularity of the hydrophobic block of the copolymer. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2207-2218, 1999

Survey of Extended-Spectrum β-Lactamases in Clinical Isolates of Escherichia coli and Klebsiella pneumoniae: Prevalence of TEM-52 in Korea

Abstract: Two hundred ninety isolates of Escherichia coli were investigated for the production of extended-spectrum beta-lactamases (ESBLs). Fourteen (4.8%) of the 290 strains were found to produce ESBLs. Each of the 14 strains produced one or two ESBLs, as follows: 10 strains produced TEM-52, 1 strain produced SHV-2a, 1 strain produced SHV-12, 1 strain produced a CMY-1-like enzyme, and 1 strain expressed SHV-2a and a CMY-1-like enzyme. Another two strains for which the MICs of ceftazidime and cefoxitin were high, were probable AmpC enzyme hyperproducers. Because of the high prevalence of TEM-52 in E. coli isolates, we further investigated the TEM-type ESBLs produced by Klebsiella pneumoniae in order to observe the distribution of TEM-52 enzymes among Enterobacteriaceae in Korea. All TEM enzymes produced by 12 strains of K. pneumoniae were identified as TEM-52. To evaluate the genetic relatedness among the organisms, ribotyping of TEM-52-producing E. coli and K. pneumoniae was performed. The ribotyping profiles of the organisms showed similar but clearly different patterns. In conclusion, TEM-52 is the most prevalent TEM-type ESBL in Korea.

A Recombinant 10-kDa Protein of Taenia solium Metacestodes Specific to Active Neurocysticercosis

Abstract: Neurocysticercosis (NCC) is an important cause of neurological disease worldwide. A 10-kDa antigen of Taenia solium metacestodes (TsMs) has been shown to be specific for immunodiagnosis of NCC. Screening of a TsM complementary DNA (cDNA) library isolated a cDNA encoding this protein. The cloned cDNA contained a 258-bp complete open-reading frame that encodes an 86-amino acid polypeptide with a calculated molecular weight of 9582 Da. It showed 73% homology with a 10-kDa antigen of T. crassiceps. The recombinant protein was expressed bacterially as a fusion protein at a high level. In immunoblot with recombinant protein, 97% (184/190) of sera from patients with active NCC showed strong reactivity, whereas 14% (4/29) of those from patients with chronic calcified NCC reacted weakly. In 180 sera from other patients with parasitic infections and from normal controls, it showed 98% specificity. A single recombinant TsM antigen has a high potential for serological differentiation of active NCC.

Cyclin D1 overexpression is an indicator of poor prognosis in resectable non-small cell lung cancer

Abstract: Cyclin D1 is one of the G1 cyclins that control cell cycle progression by allowing G1 to S transition Overexpression of cyclin D1 has been postulated to play an important role in the development of human cancers We have investigated the correlation between cyclin D1 overexpression and known clinicopathological factors and also its prognostic implication on resected non-small-cell lung cancer (NSCLC) patients Formalin-fixed and paraffin-embedded tumour tissues resected from 69 NSCLC patients between stages I and IIIa were immunohistochemically examined to detect altered cyclin D1 expression Twenty-four cases (348%) revealed positive immunoreactivity for cyclin D1 Cyclin D1 overexpression is significantly higher in patients with lymph node metastasis (500% vs 144%, P = 0002) and with advanced pathological stages (I, 10%; II, 538%; IIIa, 417%, P = 0048; stage I vs II, IIIa, P = 0006) Twenty-four patients with cyclin D1-positive immunoreactivity revealed a significantly shorter overall survival than the patients with negativity (240 ± 39 months vs 501 ± 64 months, P = 00299) Among 33 patients between stages I and II, nine patients with cyclin D1-positive immunoreactivity had a much shorter overall survival (297 ± 61 months vs 746 ± 86 months, P = 00066) These results suggest that cyclin D1 overexpression is involved in tumorigenesis of NSCLCs from early stage and could be a predictive molecular marker for poor prognosis in resectable NSCLC patients, which may help us to choose proper therapeutic modalities after resection of the tumor

The efficacy of low-dose oral corticosteroids in the treatment of vitiligo patients

Abstract: Background One of the most probable pathogeneses of vitiligo is autoimmunity. Systemic corticosteroids suppress immunity and may arrest the progression of vitiligo and lead to repigmentation. The clinical efficacy of low-dose oral corticosteroids was assessed to minimize the side-effects in actively spreading vitiligo patients. Methods Eighty-one patients with vitiligo were evaluated. The patients took daily doses of oral prednisolone (0.3 mg/kg body weight) initially for 2 months; the dosage was then reduced to half of the initial dose for the third month and was halved again for the fourth and final month. The effects of treatment were evaluated using photographs of before and after the study. Side-effects were assessed at the first, second, third and fourth month of treatment. Results Arrested progression of vitiligo and repigmentation were noted in 87.7% and 70.4% of patients respectively. Male sex, a patient age of 15 years or under, and a duration of disease of 2 years or less showed increased repigmentation with statistical significance. The side-effects of treatment were minimal and did not affect the course of treatment. Conclusions Low-dose oral corticosteroids are effective without serious side-effects in preventing the progression and inducing repigmentation of actively spreading vitiligo, which is difficult to treat with topical corticosteroids or photochemotherapy.

Halo sign on high resolution CT: findings in spectrum of pulmonary diseases with pathologic correlation.

Abstract: The halo sign in a pulmonary nodule refers to the condition in which soft tissue attenuation of a pulmonary nodule is surrounded by peripheral ground glass attenuation on high resolution CT. The halo sign can be caused by several pathologic processes: hemorrhagic pulmonary nodules, tumor cell infiltration, and nonhemorrhagic inflammatory lesions. Hemorrhagic pulmonary nodules may occur in infectious diseases including invasive pulmonary aspergillosis, mucormycosis, and candidiasis and noninfectious diseases including Wegener granulomatosis and primary and metastatic hemorrhagic tumors. Tumor cell infiltration in bronchioloalveolar carcinoma, pulmonary lymphoma, and pulmonary metastatic neoplasm may appear with the halo sign. Eosinophilic lung disease and organizing pneumonia are representative of inflammatory lesions showing the sign.

A factor analysis of the most frequently used korean personality trait adjectives

Abstract: We tested the cross‐cultural generalizability of personality structure by factor‐analysing self‐ratings of 435 Korean university students on the 406 most frequently used Korean personality trait ad...

The sen1(+) gene of Schizosaccharomyces pombe, a homologue of budding yeast SEN1, encodes an RNA and DNA helicase.

Abstract: Two polynucleotide-dependent ATPases, 95 and 181 kDa in size, have been purified to near homogeneity from cell-free extracts of Schizosaccharomyces pombe. Despite their size differences, their biochemical properties were strikingly similar. Both enzymes were capable of unwinding RNA and DNA duplexes in keeping with their ability to hydrolyze ATP in the presence of either ribo- or deoxyribopolynucleotide. In addition, they were capable of unwinding DNA/RNA or RNA/DNA hybrid duplexes and translocated in the 5' to 3' direction. These results strongly indicate that they are closely related to each other. Determination of the partial amino acid sequence of the 95-kDa enzyme revealed that it is encoded by the sen1(+)() gene, an S. pombe homologue of yeast SEN1, a protein essential for the processing of small nucleolar RNA, transfer RNA, and ribosomal RNA. The molecular weight of the S. pombe Sen1 protein (SpSen1p) predicted from the sen1(+)() open reading frame was 192.5 kDa, suggesting that the 181-kDa enzyme is likely to be a full-length protein, whereas the 95-kDa polypeptide has arisen by proteolysis. In accord with this possibility, polyclonal antibodies specific to the C-terminal region of sen1(+)() cross-reacted with both 95- and 181-kDa polypeptides. We discuss the biochemical activities associated with SpSen1p and their relevance to the apparently divergent functions ascribed to the yeast Sen1 protein in RNA metabolism.

Activator-specific requirement of yeast mediator proteins for rna polymerase ii transcriptional activation

Abstract: The multisubunit Mediator complex of Saccharomyces cerevisiae is required for most RNA polymerase II (Pol II) transcription. The Mediator complex is composed of two subcomplexes, the Rgr1 and Srb4 subcomplexes, which appear to function in the reception of activator signals and the subsequent modulation of Pol II activity, respectively. In order to determine the precise composition of the Mediator complex and to explore the specific role of each Mediator protein, our goal was to identify all of the Mediator components. To this end, we cloned three previously unidentified Mediator subunits, Med9/Cse2, Med10/Nut2, and Med11, and isolated mutant forms of each of them to analyze their transcriptional defects. Differential display and Northern analyses of mRNAs from wild-type and Mediator mutant cells demonstrated an activator-specific requirement for each Mediator subunit. Med9/Cse2 and Med10/Nut2 were required, respectively, for Bas1/Bas2- and Gcn4-mediated transcription of amino acid biosynthetic genes. Gal11 was required for Gal4- and Rap1-mediated transcriptional activation. Med11 was also required specifically for MFalpha1 transcription. On the other hand, Med6 was required for all of these transcriptional activation processes. These results suggest that distinct Mediator proteins in the Rgr1 subcomplex are required for activator-specific transcriptional activation and that the activation signals mediated by these Mediator proteins converge on Med6 (or the Srb4 subcomplex) to modulate Pol II activity.

Isolation, characterization, and stability of positional isomers of mono-PEGylated salmon calcitonins.

Abstract: Purpose. To separate and characterize the different positional isomers of mono-PEGylated salmon calcitonins (mono-PEG-sCTs) and to evaluate the effects of the PEGylation site on the stability of different mono-PEG-sCTs in rat kidney homogenate.

Contribution of Ca2+-activated K+ channels and non-selective cation channels to membrane potential of pulmonary arterial smooth muscle cells of the rabbit.

Abstract: 1Using the perforated patch-clamp or whole-cell clamp technique, we investigated the contribution of Ca2+-activated K+ current (IK(Ca)) and non-selective cation currents (INSC) to the membrane potential in small pulmonary arterial smooth muscle cells of the rabbit. 2The resting membrane potential (Vm) was -39·2 ± 0·9 mV (n= 72). It did not stay at a constant level, but hyperpolarized irregularly, showing spontaneous transient hyperpolarizations (STHPs). The mean frequency and amplitude of the STHPs was 5·6 ± 1·1 Hz and -7·7 ± 0·7 mV (n= 12), respectively. In the voltage-clamp mode, spontaneous transient outward currents (STOCs) were recorded with similar frequency and irregularity. 3Intracellular application of BAPTA or extracellular application of TEA or charybdotoxin suppressed both the STHPs and STOCs. The depletion of intracellular Ca2+ stores by caffeine or ryanodine, and the removal of extracellular Ca2+ also abolished STHPs and STOCs. 4Replacement of extracellular Na+ with NMDG+ caused hyperpolarization Vm of without affecting STHPs. Removal of extracellular Ca2+ induced a marked depolarization of Vm along with the disappearance of STHPs. 5The ionic nature of the background inward current was identified. The permeability ratio of K+ : Cs+ : Na+ : Li+ was 1·7 : 1·3 : 1 : 0·9, indicating that it is a non-selective cation current (INSC). The reversal potential of this current in control conditions was calculated to be -13·9 mV. The current was blocked by millimolar concentrations of extracellular Ca2+ and Mg2+. 6From these results, it was concluded that (i) hyperpolarizing currents are mainly contributed by Ca2+-activated K+ (KCa) channels, and thus STOCs result in transient membrane hyperpolarization, and (ii) depolarizing currents are carried through NSC channels.

Core-stabilized Polymeric Micelle as Potential Drug Carrier: Increased Solubilization of Taxol

Abstract: WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW Poly(ethylene glycol-b-lactide) possessing a methoxygroup at the poly(ethylene glycol) (PEG) chain end anda polymerizable methacryloyl group at the poly(lacticacid) (PLA) chain end (MeO–PEG/PLA–methacryloyl)was prepared by an anionic ring-opening polymerizationof ethylene oxide and DL -lactide in tandem mannerinitiatedwithapotassium2-methoxyethanolate,followedby end-capping with an excess of methacrylic anhydride.The molecular weight of the obtained polymer wascontrolled by the initial monomer/initiator ratio, whichwas confirmed by the combination of gel permeationchromatography and nuclear magnetic resonance ana-lyses. The functionality of the methacryloyl–PLA endwas almost quantitative. The MeO–PEG/PLA–metha-cryloyl (38/35; these numbers in parentheses denote themolecular weights of PEG and PLA segments divided by100, respectively) formed a core–shell type sphericalmicelle in aqueous media obtained by a dialysistechnique, the cumulant diameter of which was ca.30nm with very low polydispersity factor.The methacryloyl group adjacent to the PLA waspolymerized in the PLA core of the micelle. Thepolymerizationproceededthermallywithradicalinitiatorand photochemically with photo-initiator to producecore-polymerized nanoparticles, which was found byspectroscopic and light-scattering techniques. Taxol-incorporated micelles were prepared to entrap Taxol intoMeO–PEG/PLA–methyacryloyl block copolymer mi-celles by the oil/water emulsion method. Copyright O1999 John Wiley & Sons, Ltd.KEYWORDS: polymeric micelle; stable nanoparticle;drugdeliverysystem;PEG/PLAblockcopolymer;micellestability; taxol

A high speed and low power phase-frequency detector and charge-pump

Abstract: In this paper, we introduce a high-speed and low power Phase-Frequency Detector (PFD) that is designed using modified TSPC (True Single-Phase Clock) positive edge triggered D flip-flop. This PFD has a simpler structure with using only 19 transistors. The operation range of this PFD is over 1.2 GHz without additional prescaler circuits. Furthermore, the PFD has a dead zone less than 0.01 ns in the phase characteristics and has low phase sensitivity errors. The phase and frequency error detection range is not limited as in the case of the pt-type and nc-type PFDs. Also, the PFD is independent from the duty cycle of input signals. A new charge-pump circuit is presented that is designed using a charge-amplifier. A stand-by current enhances the speed of charge-pump and removes the charge-sharing which causes a phase noise in the charge-pump PLL. Also, the effects of clock feed-through are reduced by separating the output stage from UP and down signal. The simulation results base on a third-order PLL are presented to verify the lock-in process with the proposed PFD and charge-pump circuits. The PFD and charge-pump circuits are designed using 0.8 /spl mu/m CMOS technology with 5 V supply voltage.

Evaluation of solid breast lesions with power Doppler sonography.

Abstract: Purpose We compared the abilities of power and conventional color Doppler sonography to depict the vascularity of solid breast lesions and evaluated the usefulness of power Doppler sonography in differentiating between benign and malignant breast lesions. Methods One hundred two solid breast lesions (59 benign and 43 malignant lesions) were studied with power and color Doppler sonography. Power and color Doppler sonograms were retrospectively compared for the depiction of blood flow signals. Power Doppler images were also reviewed for the amount of Doppler signals, pattern of vascularity, and morphology of vessels. The sensitivity, specificity, and accuracy of the 2 techniques were calculated. Results Compared with color Doppler sonography, power Doppler sonography depicted flow superiorly in 61 cases (60%) and equally in 41 cases (40%). On power Doppler sonography, the incidence of marked blood flow in malignant lesions (65%) was higher than that in benign lesions (39%). The pattern of vascularity was predominantly central (86%) and/or penetrating (65%) more often in malignant lesions than in benign lesions (51% and 34%, respectively). Branching (56%) and disordered vessels (42%) were seen more often in malignant lesions than in benign lesions (22% and 8%, respectively). The sensitivity, specificity, and accuracy in diagnosing malignancy were 64%, 76%, and 71%, respectively, for power Doppler sonography and 77%, 76%, and 76% for color Doppler sonography. Conclusions Power Doppler sonography was more sensitive than color Doppler sonography in the detection of flow in solid breast lesions. Although power Doppler sonography was not more effective in diagnosing malignant lesions, central and penetrating vascularity patterns and branching and disordered vessels seem to be helpful findings in predicting malignancy. © 1999 John Wiley & Sons, Inc. J Clin Ultrasound 27:231–237, 1999.