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Presents a study that examined yttrium compound superconducting thin films by using laser-deposition. Information on the structure and morphology of the films; Discussion on the surface morphology and electron channeling patterns of the thin films; Use of scanning electron microscope and atomic force microscope.

A novel and effective method for target cells capture and detection is developed in a label-free and real-time mode. The cultured cell line (TZMbl) expressed as CD4+ was used as the positive CD4+ T lymphocytes for target cells capture and detection experiments. The target cells were captured on various surfaces (such as glass, polydimethylsiloxane, and metal) based on a specific immunity method. The gold surface of the surface plasmon resonance (SPR) sensing chip modified with a nano denaturalised bovine serum albumin layer had the best capture capacity. A total of 90.9% positive CD4+ T lymphocytes were captured with a slow flow rate of 5 μl/min, whereas 84.1% of cells were kept with a fast flow rate of 2 ml/min. Furthermore, the captured positive cells on the SPR sensing chip were detected on-line by using author's home-made SPR biosensor. From the experimental results, 75 cells/μl could produce an obvious change in the SPR response signal, which holds great potential for target cells capture, reorganisation and further analysis of CD4+ T lymphocytes in human peripheral blood. [ABSTRACT FROM AUTHOR]

This paper presents an electrochemical-surface plasmon resonance imaging (EC-SPRI) system, enabling the characterization of optical and electrical properties of cells, simultaneously. The developed surface plasmon resonance (SPR) imaging system was capable of imaging micro cavities with a dimension of 10 μm × 10 μm and differentiated glycerol solutions with a group of refractive indices (RIs). Furthermore, the EC-SPRI system was used to image A549 cells, suggesting corresponding RI and morphology changes during the cell death process. In the end, electrochemical and SPR methods were used in combination, recording oxidation peaks of A549 cells in the cyclic voltage curves and SPR response unit increase, simultaneously. [ABSTRACT FROM AUTHOR]

Optically transparent Sb-doped SrSb 0.05 Ti 0.95 O 3 thin film with a transmittance higher than 90% in visible region is grown on SrTiO 3 (001) substrate by pulsed laser deposition. The thin film shows a metallic-like conductivity at room temperature. The transparent conducting property of the SrSb 0.05 Ti 0.95 O 3 thin film is due to its band structure. [ABSTRACT FROM AUTHOR]

Epidermal Growth Factor (EGF) is a small growth factor containing 53 amino acid residues capable of stimulating the proliferation of both mesenchymal and epithelial cells. Comparison of the amino acid sequences of EGF from several species, and related proteins that can bind to the EGF receptor (e.g. TGFα, VGF, heparin-binding EGF, and betacellulin), suggests that Leu 47 , which is highly conserved, is important for biological function. Additionally, we have shown previously, using a combination of trypsin and carboxypeptidase Y digestion of native murine EGF, that removal of Leu 47 results in more than 100-fold decrease in both receptor binding and mitogenic activity. We now describe a micromethod for the rapid generation of C-terminally modified EGFs to investigate further the role of C-terminal residues in determining functional activity. These analogues have been generated by digesting native murine EGF with trypsin, purifying the biologically inactive, but structurally intact, EGF 1-45 core by micropreparative RP-HPLC, and then reversing the action of trypsin to couple synthetic peptides (e.g. DL, DI, DF, EL, DLLW) onto the C-terminus of the EGF 1-45 core. This enzymic semisynthesis method allows multiple derivatives to be generated rapidly from microgram quantities of EGF 1-45 in sufficient quantities for sensitive biological and physicochemical analysis. We have validated the method by regenerating EGF 1-47 from EGF 1-45 with equivalent mitogenic and receptor binding activity to EGF 1-47 generated from wild type EGF by digestion with trypsin and carboxypeptidase Y. We have also investigated the effect of substituting alternative normal or non-physiological amino acids (e.g. allo-Ile) for Asp 46 , Leu 47 or Arg 48 . Even small changes in these C-terminal residues reduce the mitogenic potency of the analogue. [ABSTRACT FROM AUTHOR]

The structures of BaTiO[sub 3] thin films and BaTiO[sub 3]/YBa[sub 2]Cu[sub 3]O[sub 7-δ] bilayer films grown on SrTiO[sub 3] and LaAlO[sub 3] substrates, respectively by pulsed laser deposition, have been investigated by X-ray triple-axis diffraction. The orientation, the interface mismatch and strain status, and the in-plane and perpendicular lattice constants of the epilayers have been determined by reciprocal space map analysis. The results show that both the lattice constants and the structural imperfections of the BaTiO[sub 3] layers are relevant to the oxygen partial pressure. The a[sub ⊥]/a... increases while the full width at half maximum (FWHM) of the rocking curves decreases with the decrease in the partial oxygen pressure. [ABSTRACT FROM AUTHOR]

Optically transparent Sb-doped SrTiO[sub 3] thin films with a transmittance higher than 95% in most of the visible region have been grown on SrTiO[sub 3] (001) substrate by pulsed laser deposition. The films behave as an n-type semiconductor between 10 K and room temperature. The carrier concentration and mobility of the films at room temperature are ∼5.8x10[sup 17] cm[sup -3] and ∼6.4 cm[sup 2]/V s, respectively. X-ray photoelectron spectroscopy measurement reveals that the delocalized electrons from the Sb dopants give rise to deep impurity levels within the band gap of the parent compound, which are responsible for the electrical conduction observed. The wide band gap and low density of states in the conduction band account for transparency of the films. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

A Seebeck coefficient measurement apparatus for high resistance organic semiconductor materials has been designed and built. It can measure materials with resistance over 7 × 1012 Ω. This is the highest material resistance value ever reported for Seebeck coefficient measurement. A cyclic temperature gradient generation technique and a corresponding algorithm are proposed to eliminate the negative effects of the long term drift of Seebeck voltage. Sources of errors in these measurements are discussed. [ABSTRACT FROM AUTHOR]

This paper presents a surface plasmon resonance (SPR) imaging system based on a low-cost, convenient poly(dimethylsiloxane) (PDMS) prism featured with a close contact with the gold film. Compared to conventional glass prism, both numerical simulations and experimental studies indicated a deeper but wider absorption peak with a higher coupling angle for the PDMS based prism. System repeatability was quantified by the cycled detection of helium and air, with the effect of the flow rate investigated. Furthermore, five types of gases (nitrogen, air, oxygen, hydrogen, and helium) were detected and differentiated by the SPR system, with a calculated sensitivity of 5 × 10-6 RIU. [ABSTRACT FROM AUTHOR]

In this paper, a micro gas chromatography (μGC) system contained a μGC column and a micro thermal conductivity detector (μTCD) was proposed. In order to reduce the volume of the system, some micro heaters were integrated on the surface and backside of the GC column, which could provide a robust temperature programming capability and rapidly increase the temperature of the μGC column. In addition, a silicon-glass μTCD with four-thermistor thermal conductivity cells that can offer significant advantages over previously reported designs including low dead volume, good thermal isolation, and elimination of the thermal noise was proposed in this paper. Experimental results have indicated that the μGC system with a detection limit of several ppm concentration levels separated and detected the benzene, toluene, and styrene in less than 3 min, and the μGC system also exhibited a good linear response in the test range. [ABSTRACT FROM AUTHOR]

Toll-like receptors mediate immune responses via recognition of pathogen-associated molecular patterns. Polymorphisms of toll-like receptors may affect their recognition of pathogen-associated molecular patterns, leading to varied host resistance to pathogenic infections. However, little is known about the polymorphisms of chicken toll-like receptors (ChTLR) among breeds. In this study, we cloned ChTLR2 type 1 and type 2 genes from 7 chicken breeds and analyzed their sequences. It was found that there were 10 amino acid polymorphism sites in ChTLR2 type 1 and type 2, among which 6 sites were in type 1 (5 sites in the extracellular domain and 1 site in the cytoplasmic domain) and 4 sites were in type 2 (all 4 sites in the extracellular domain). These results demonstrate that ChTLR2 type 1 and type 2 genes are polymorphic among chicken breeds, suggesting a varied resistance among breeds of chicken. We found that Laiwu Black chicken breeds have distinctive polymorphic sites at I699T in the type 1 and H561R in the type 2 ChTLR2 gene. Beijing Fatty chickens have distinctive sites at Q45R in type 1 and V66L in type 2. Nongda No.3 Chickens have distinctive sites at L115P, H232Y, and T494A in type 1. Hy-Line variety brown chickens have distinctive sites at I311V in type 2. Beijing White 939 chickens have distinctive sites at E284G in type 1 and A22V in type 2. These findings may provide some clues toward understanding the resistance of lighter chickens to salmonellosis. [ABSTRACT FROM AUTHOR]

An efficient all-solid-state picosecond (ps) ultraviolet (UV) laser at 335 nm was demonstrated based on frequency quadrupling of a mode-locked 1342 nm MOPA system. An output power of 0.95 W was obtained under a fundamental wave power of 16.38 W, corresponding to a conversion efficiency of 5.8% from infrared to UV. The repetition rate and pulse duration were 77 MHz and 20.2 ps, respectively. The beam quality factor M(2) was measured to be 1.56. This is, to the best of our knowledge, the highest output power at 335 nm.

Peptide was polymerized by a novel method: compound containing double bond between two carbons such as acdryloyl chloride was introduced into peptide during peptide synthesis, then it was transformed to a polymer which has a poly propionyl core matrix with peptide branches by radical polymerization either after being cleaved from resin or before being cleaved from resin according to the peptide physical-chemical character. According to this design, the macromolecules with average MW about 40 kD for poly-Osteogenic Growth Peptide (poly-OGP), 25 KD for poly-penetratin could be produced. Poly-OGP was further applied for antibody preparation and immunoassays. Immunizing New Zealand rabbits, we obtained the antiserum with titer of 2.5x10(4), examined by enzyme-linked immunosorbent assay (ELISA), without cross-reaction with bovine serum albumin (BSA), while the antiserum produced by using BSA as peptide carrier strongly reacted with BSA (with titer of more than 50x10(4) for BSA). Based on competitive ELISA, the anti-poly-OGP antibody showed much better immunoreactive sensitivity than anti-BSA-OGP antibody by comparing their IC(50) toward OGP. The antigen determinant of OGP and the OGP content in the serum of mice, determined by anti-poly-OGP antibody, showed that the anti-polypeptide antibody can be used as tools for immunoassay. Thus, the polypeptide system is not only a new approach for preparing synthetic peptide antibody for immunoassays but also provided the prospect for preparing synthetic peptide-based vaccine.

The methylotrophic yeast Pichia pastoris, which proved successful in producing many heterologous proteins, was used to express an insulin precursor. A transformant with a high copy number of the gene integrated into the chromosome was obtained by the dot-blotting method. In high-density fermentation using a simple culture medium composed mainly of salt and methanol, the expression level reached 1.5 g/L. A simple two-step method was established to purify the expression product from the culture medium with an overall recovery of about 80%. After tryptic transpeptidation, human insulin with full receptor binding capacity and biological activity was obtained. In the presence of zinc, the recombinant human insulin could be crystallized in the rhombohedral form., (Copyright 2001 John Wiley & Sons, Inc.)

Orphanin FQ (also known as nociceptin) is a 17-amino-acid peptide which acts as a potent endogenous agonist of the orphan opioid receptor-like (ORL1) receptor. Endomorphin-1, a 4-amino-acid peptide discovered recently, is a potent and selective endogenous agonist for the mu-opiate receptor. In the present study, the effect of OFQ or/and endomorphin-1 on the response to noxious thermal stimuli was observed using the tail-flick test in rats. Intracerebroventricular (i.c.v.) administration of OFQ (1, 5 microg) could shorten tail-flick latency; In contrast, intrathecal (i.t.) administration of OFQ (1, 2 or 10 microg) could increase the latency; i.c.v. (1, 2, 5 microg) or i.t. (0.2, 2, 5 microg) administration of endomorphin-1 dose-dependently increased the latency, indicating an analgesic effect. Furthermore, OFQ (0.1-5 microg) when intraventricularly injected together with endomorphin-1 (5 microg), could dose-dependently reverse the analgesia induced by the latter. On the contrary, OFQ (1 microg) intrathecally injected together with endomorphin-1 (0.2 microg) could further increase the tail-flick latency. The results showed that OFQ at the supraspinal level produces hyperalgesia and is antagonistic to endomorphin-1, while at the spinal level it produces analgesia and is synergic with endomorphin-1. Different interaction mechanism between OFQ and endomorphin-1 in the brain and the spinal cord is thus suggested., (Copyright 1999 Elsevier Science B.V.)

DsbC, a periplasmic disulfide isomerase of Gram-negative bacteria, displays about 30% of the activities of eukaryotic protein disulfide isomerase (PDI) as isomerase and as thiol-protein oxidoreductase. However, DsbC shows more pronounced chaperone activity than does PDI in promoting the in vitro reactivation and suppressing aggregation of denatured D-glyceraldehyde-3-phosphate dehydrogenase (GAPDH) during refolding. Carboxymethylation of DsbC at Cys98 decreases its intrinsic fluorescence, deprives of its enzyme activities, but lowers only partly its chaperone activity in assisting GAPDH reactivation. Simultaneous presence of DsbC and PDI in the refolding buffer shows an additive effect on the reactivation of GAPDH. The assisted reactivation of GAPDH and the protein disulfide oxidoreductase activity of DsbC can both be inhibited by scrambled and S-carboxymethylated RNases, but not by shorter peptides, including synthetic 10- and 14-mer peptides and S-carboxymethylated insulin A chain. In contrast, all the three peptides and the two nonnative RNases inhibit PDI-assisted GAPDH reactivation and the reductase activity of PDI. DsbC assists refolding of denatured and reduced lysozyme to a higher level than does PDI in phosphate buffer and does not show anti-chaperone activity in HEPES buffer. Like PDI, DsbC is also a disulfide isomerase with chaperone activity but may recognize different folding intermediates as does PDI.

Aim: To study the effect of orphanin FQ (OFQ), a newly discovered heptadecapeptide, on nociception and opioid analgesia., Methods: The intracerebroventricular (i.c.v.) and intrathecal (i.t.h.) injections were used to give the drugs. The tail-flick model of rats were used to test the pain threshold., Results: OFQ (i.c.v. or i.t.h.) 0.1 microgram had no effect on nociception but 0.5-10 micrograms induces hyper-reaction of rat to noxious electric stimulus; the decapeptide (OFQ1-10 i.c.v.), a fragment of the OFQ, did not affect the pain reaction of rats. Fentanyl (1 microgram, i.c.v. or i.t.h.), a selective mu-receptor agonist, DSLET (5 micrograms, i.c.v. or i.t.h.), a selective delta-receptor agonist, or U50488H (1 microgram, i.t.h.), a kappa-receptor agonist, induced an increase in pain threshold, when OFQ (0.1 or 1 microgram) was added together with one of them (except for the ith injection of DSLET), the increase of pain threshold was reduced obviously., Conclusion: OFQ induces hyperalgesia and antagonizes opioid analgesia mediated by mu- and delta-receptors in the brain and by mu- and kappa- but not delta-receptors in the spinal cord of rats.

The influence of orphanin FQ (OFQ) (a newly discovered 17-amino acid peptide) on acupuncture analgesia (AA) was assessed in rat tail-flick model. Intracerebroventricular (i.c.v.) injection of OFQ (1 microgram) elicited a significant decrement of pain threshold which was abolished by the repeated pretreatment with antisense oligonucleotide (ASO) to OFQ receptor. Electroacupuncture (EA) induced an obvious analgesic effect; when OFQ was used combined with EA, it showed a dose-dependent effect on antagonizing the EA analgesia. When rat was repeatedly i.c.v. injected with ASO to block the synthesis of OFQ receptor, the EA analgesia was enhanced markedly. In this instance, the OFQ did not show antagonistic effect on EA analgesia any more. The results suggest that the OFQ play its antagonistic role on EA analgesia via activating OFQ receptor.

The tissue-type plasminogen activator (t-PA) has been found to bind reversibly to human fibronectin (Fn). To locate the binding site on Fn for t-PA, the Fn was degraded with N-tosyl-L-phenylalanyl chloromethyl ketone-treated trypsin, and the resulting fragments were monitored by the enzyme-linked immunosorbent assay method for t-PA binding activities. A 20-kDa fragment with t-PA binding activity was identified, separated, and purified. It was subjected to further degradation with Staphylococcus aureus proteinase V8. An active 10-kDa fragment was finally purified by reverse-phase high pressure liquid chromatography on a C3 column. The dissociation constants of the binding of Fn and the 10-kDa fragment to t-PA were estimated by Scatchard plot to be 1.13 x 10(-8) and 2.08 x 10(-8) M, respectively. The 10-kDa fragment was sequenced and proved to be located at the 8-9th domains of type I homology of Fn. Based on the structural analysis of the 8-9th domains, a heptadecapeptide corresponding to the sequence Thr535-Glyl551 of Fn, which resided at the large disulfide loop of domain (I-9), was designed and synthesized. Both the 10-kDa fragment and the synthetic peptide could competitively inhibit the binding of Fn to t-PA. The synthetic peptide showed about one-tenth of the binding activity of Fn to t-PA with a dissociation constant of 1.35 x 10(-7) M and was proved to be the binding region of Fn for t-PA. In addition, like the intact Fn, both the 10-kDa fragment and the synthetic peptide could remarkably enhance the amidolytic activity of t-PA in a dose-dependent manner, as shown by using S-2288 as a chromogenic substrate.

In view of the similarity of the charge distribution between fibrin A alpha 148-161 and A chain 149-157 of urokinase, the latter might compete with fibrin A alpha 148-161 when single chain pro-urokinase is converted to double chain urokinase. To test this, the stretch of urokinase A chain 135-157 was separated from the low molecular weight urokinase, a competitive binding between this stretch and fibrin to tPA kringle-2 was shown by radio-binding assay. The inhibition of the stretch on the fibrin stimulated activation of plasminogen was demonstrated in the caseinolytic system. The synthesized novapeptide urokinase A chain 149-157 (R-peptide) showed a significant inhibition on the activation of plasminogen in the presence of fibrin. By contrasting finely with R-peptide, a synthesized novapeptide in which Arg154 and Arg156 were replaced by Asp (D-peptide) did not show any inhibition effect on the fibrin stimulated activation of plasminogen by tPA. These results suggest that the positively charged residues in the stretch 149-157 of urokinase are crucial for the inhibition of fibrin binding with the kringle domain of urokinase.

One approach to the localization of functionally active regions of human granulocyte-macrophage colony-stimulating factor (hGM-CSF) is to map the epitopes recognized by neutralizing anti-hGM-CSF monoclonal antibodies. We have defined the epitope recognized by one neutralizing antibody (LMM102) using proteolytic fragments obtained by enzymic digestion of bacterially synthesized hGM-CSF. RP-HPLC fractionation of a tryptic digest resulted in the identification of an immunoreactive "tryptic core" peptide containing 66 amino acids (52% of the protein). Further digestion of this "tryptic core" with S. aureus V8 protease produced a unique immunoreactive hGM-CSF product comprising two peptides, residues 86-93 and 112-127, linked by a disulfide bond between residues 88 and 121. The individual peptides, generated by reduction with dithiothreitol, were not recognized by the antibody. An analog of this peptide has been synthesized chemically and shown to have similar immunoreactivity to the epitope obtained by enzymic digestion. A series of modified peptides has also been synthesized to identify further the region required for antibody recognition.