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Biomedical subjects

Li Jiang

Publications and source records attributed to Li Jiang.

At least 55 records · Page 3Linked to original sources
PubMed2006

[Histopathological study on the regularity of pyriform sinus carcinoma invading adjacent tissue and structure].

OBJECTIVE: To explore the regularity invading adjacent tissue of pyriform sinus carcinoma. METHODS: The whole organ serial section of 68 total or partial laryngectomy and hypopharyngectomy specimen of pyriform sinus carcinoma were histopathologically studied. RESULTS: In 68 pyriform sinus carcinoma, invaded ventricular and paraglottic spaces was 63 and 38 cases respectively, the difference of invasive frequency of both spaces was significantly marked (chi2 = 21.37, P < 0.01). Thyroid cartilage had the most invaded frequency of 92.6% (63/68). The all touching and pressing invasion of laryngeal cartilage was 89 times, and infiltrating invasion was 51 times. The invasive frequency of lateral cricoarytenoid muscle, posterior cricoarytenoid one, thyroarytenoid and interarytenoid ones were 63.2% (43/68), 57.4% (39/68), 55.9% (38/68), 51.5% (35/68) respectively. The invasive frequency of cricoarytenoid and cricothyroid joints were 30.9% (21/68), 17.6% (12/68) respectively. The invasive frequency of superior laryngeal nerve was 67.7% (44/65) , and more than that of recurrent laryngeal nerve (18/65, 27.7%). The pyriform sinus medial wall carcinoma was 14 cases, lateral wall carcinoma 18 cases, medial and lateral wall carcinoma 36 cases. The invaded pyriform sinus apex was 34 cases, normal its apex was 26 ones, submucous invasion of its apex was 8 ones. Light lymphocytic invasion was 66.2% (45/68) and seen most in pyriform sinus carcinoma. Submucous and leaping invasion of pyriform sinus carcinoma were 24 and 8 cases. CONCLUSIONS: Intralaryngeal invasion of pyriform sinus carcinoma arose through paraglottic space first. Laryngeal cartilage membrane and their cartilage were anatomical obstacle against cancerous invasion. Lateral cricoarytenoid muscle, posterior cricoarytenoid one, thyroarytenoid and interarytenoid ones were often invaded. Pyriform sinus medial wall carcinoma invaded intralaryngeal structure easily, its lateral wall carcinoma may invade upward, downward and outward along thyroid cartilage interior wall, medial and lateral wall carcinoma may invade intralaryngeal and extralaryngeal structure, and was the most serious lesion. The invasion of pyriform sinus apex is an important sign of pyriform sinus carcinoma spreading downward to inferior and peripheral tissues of hypopharynx.

Adult↗
PubMed2005

Three-dimensional self-organization of supramolecular self-assembled porphyrin hollow hexagonal nanoprisms.

A self-assembly technique assisted with surfactant is developed to fabricate one-dimensional (1D) nanostructure of zinc meso-tetra (4-pyridyl) porphyrin. The so-prepared nanostructure appears in a shape of hollow hexagonal nanoprism with uniform size. The length and aspect ratio of the nanoprisms is easily tunable by controlling the stoichiometric ratio of porphyrin over surfactant. The internal structure of the nanoprisms is well described by XRD. Furthermore, as a result of dispersivity and regular geometric shape, these nanoprisms can readily self-organize into an ordered, smectic three-dimensional (3D) architecture through simple evaporation of the solvent. The results should be significant in porphyrin crystallization and porphyrin application in optoelectronic device, catalysis, drug delivery, and molecular filtration.

Journal Article↗
PubMed2005

Controllable pt nanoparticle deposition on carbon nanotubes as an anode catalyst for direct methanol fuel cells.

We report a novel process to prepare well-dispersed Pt nanoparticles on CNTs. Pt nanoparticles, which were modified by the organic molecule triphenylphosphine, were deposited on multiwalled carbon nanotubes by the organic molecule, which acts as a cross linker. By manipulating the relative ratio of Pt nanoparticles and multiwalled carbon nanotubes in solution, Pt/CNT composites with different Pt content were achieved. The so-prepared Pt/CNT composite materials show higher electrocatalytic activity and better tolerance to poisoning species in methanol oxidation than the commercial E-TEK catalyst, which can be ascribed to the high dispersion of Pt nanoparticles on the multiwalled carbon nanotube surface.

Catalysis↗
PubMed2005

Generation of large numbers of transgenic Kentucky bluegrass (Poa pratensis L.) plants following biolistic gene transfer.

A very efficient transformation system, using biolistic bombardment, has been developed for the production of transgenic plants of Kentucky bluegrass (Poa pratensis L.). Embryogenic calli, initiated from immature embryos, were transformed either with pAct1IHPT-4 containing the hygromycin phosphotransferase (hpt) gene or with pDM803 containing the phosphinothricin acetyltransferase (bar) gene and the beta-glucuronidase (uidA) gene. In total 119 independent transgenic plants were recovered from 153 hygromycin-resistant lines. Bialaphos selection yielded a total of 99 bialaphos-resistant lines and from these 34 independent transgenic plants were recovered. Southern blot analysis demonstrated the independent nature of the transgenic plants and also revealed a complex transgene integration pattern with multiple insertions.

Biolistics↗
PubMed2005

Determination of oleanolic acid in human plasma and study of its pharmacokinetics in Chinese healthy male volunteers by HPLC tandem mass spectrometry.

A highly selective and sensitive HPLC-ESI-MS-MS method was developed for the determination of oleanolic acid in human plasma. The oleanolic acid and glycyrrhetinic acid (internal standard) were recovered from plasma with ethyl acetate liquid-liquid extraction. The organic extracts were dried under a stream of warm nitrogen, reconstituted in mobile phase and injected into a Zorbax-Extend ODS analytical column (150 mm x 4.6 mm i.d., 5 microm), with the mobile phase consisting of methanol-ammonium acetate (32.5 mM) (85:15, v/v) pumped at a flow rate of 1.0 ml/min, and 30% of the eluent was split into a MS system with electrospray ionization tandem mass (ESI-MS-MS) detection in negative ion mode. The tandem mass detection was performed on a Finnigan Surveyor LC-TSQ Quantum Ultra AM tandem mass spectrometer operated in selected reaction monitoring mode. The parent to product ion combinations of m/z 455.4-->455.4 and 469.3-->425.2 at 38 V 1.5 mTorr Ar CID were used to quantify oleanolic acid and glycyrrhetinic acid, respectively. The assay was validated in the concentration range of 0.02-30.0 ng/ml for oleacolic acid when 0.5 ml of plasma was processed. The precision of the assay (expressed as relative standard deviation, R.S.D.%) was less than 15% at all concentrations levels within the tested range and adequate accuracy, and the limit of quantification was 0.02 ng/ml. The established method was applied for the pharmacokinetics study of oleanolic acid capsules in 18 healthy male Chinese volunteers with the mean values of C(max), T(max), AUC(0-48), AUC(0-infinity), t(1/2,) CL/F, and V/F of oleanolic acid after p.o. a single 40 mg dose obtained were 12.12 +/- 6.84 ng/ml, 5.2 +/- 2.9h, 114.34 +/- 74.87 ng h/ml, 124.29 +/- 106.77 ng h/ml, 8.73 +/- 6.11 h, 555.3 +/- 347.7 L/h, and 3371.1 +/- 1,990.1 L, respectively.

Acetates↗
PubMed2005

Boron-doped diamond microdisc arrays: electrochemical characterisation and their use as a substrate for the production of microelectrode arrays of diverse metals (Ag, Au, Cu)via electrodeposition.

A novel boron-doped diamond (BDD) microelectrode array is characterised with electrochemical and atomic force microscopic techniques. The array consists of 40 micron-diameter sized BDD discs which are separated by 250 microns from their nearest neighbour in a hexagonal arrangement. The conducting discs can be electroplated to produce arrays of copper, silver or gold for analytical purposes in addition to operating as an array of BDD-microelectrodes. Proof-of-concept is shown for four separate examples; a gold plated array for arsenic detection, a copper plated array for nitrate analysis, a silver plated array for hydrogen peroxide monitoring and last, cathodic stripping voltammetry for lead at the bare BDD-array.

Arsenic↗
PubMed2005

All-diamond microelectrode array device.

We report the development of all-diamond microelectrochemical devices, namely, a microelectrode array (MEA), in which a periodic array structure with well-defined diameters, distance, and hexagonal unit cell pattern is micromachined using a combination of state-of-the-art microwave-induced plasma growth and laser ablation shaping techniques to prepare and coat a patterned boron-doped diamond (BDD) substrate with an intrinsic diamond insulating layer. The active BDD element can be tuned to between 10 and 50 microm in diameter with a 10 times diameter center-to-center distance between two adjacent conducting elements, which are exactly coplanar to the dielectric surroundings. This type of device should enable applications in harsh conditions such as high temperature, high pressure, and resistive media under dynamic flow regimes.

Journal Article↗
PubMed2005

Towards transition modelling for supersonic laminar flow control based on spanwise periodic roughness elements.

Laminar flow control (LFC) is one of the key enabling technologies for quiet and efficient supersonic aircraft. Recent work at Arizona State University (ASU) has led to a novel concept for passive LFC, which employs distributed leading edge roughness to limit the growth of naturally dominant crossflow instabilities in a swept-wing boundary layer. Predicated on nonlinear modification of the mean boundary-layer flow via controlled receptivity, the ASU concept requires a holistic prediction approach that accounts for all major stages within transition in an integrated manner. As a first step in developing an engineering methodology for the design and optimization of roughness-based supersonic LFC, this paper reports on canonical findings related to receptivity plus linear and nonlinear development of stationary crossflow instabilities on a Mach 2.4, 73 degrees swept airfoil with a chord Reynolds number of 16.3 million.

Journal Article↗
PubMed2005

4-Nitrobenzylamine partially intercalated into graphite powder and multiwalled carbon nanotubes: characterization using X-ray photoelectron spectroscopy and in situ atomic force microscopy.

We report the characterization of partial intercalation of 4-nitrobenzylamine (4-NBA) into edge-plane or edge-plane-like defect sites on the surface of both graphite powder and "bamboo-like" multiwalled carbon nanotubes (MWCNTs) using X-ray photoelectron spectroscopy (XPS). By comparing the XPS spectra of 4-NBA derivatized graphite powder and MWCNTs with that of graphite powder treated with benzylamine in a similar fashion, we conclude that benzylamine itself does not undergo partial intercalation. Using in situ atomic force microscopy, we are able to observe the partial intercalation of 4-NBA into an edge-plane-like "step" defect on the surface of a highly ordered pyrolytic graphite crystal in real time. Together these observations provide further evidence for the partial intercalation of 4-NBA and lead us to propose a new hypothesis to explain this phenomenon.

Journal Article↗
PubMed2005

Detection of peritoneal micrometastasis by reverse transcriptase-polymerase chain reaction for heparanase mRNA and cytology in peritoneal wash samples.

BACKGROUND: Peritoneal dissemination is the most common pattern of metastasis in advanced gastric carcinoma with serosal invasion. In the present study, we have reported the clinical relevance of a new diagnostic method with reverse transcriptase-polymerase chain reaction (RT-PCR) assay using heparanase as a target gene for detection of free cancer cells in peritoneal washes. METHODS: Intraoperative peritoneal washes were obtained from 48 patients who underwent surgery for gastric cancer. RT-PCR analysis with primers specific for heparanase and conventional cytological examination were performed subsequently. RESULTS: Heparanase RT-PCR was capable of detecting at least 10 tumor cells in 10 ml peritoneal wash fluid. There was no detectable heparanase expression in normal gastric epithelial cells and peritoneal wash samples from patients with benign disease. Twenty-five (52%) patients with gastric cancer had a detectable heparanase expression. Its positive rate was 100% and 59% for the cases with clinically evident peritoneal metastasis and serosal invasion, respectively, both of which are higher than that of cytology. CONCLUSIONS: Heparanase mRNA detected in peritoneal lavaged fluid might indicate the presence of free cancer cells in peritoneal cavity. The high sensitivity of RT-PCR based heparanase assay made it a candidate molecular marker for detecting peritoneal micrometastasis.

Adult↗
PubMed2005

Gold hollow nanospheres: tunable surface plasmon resonance controlled by interior-cavity sizes.

Uniform gold hollow nanospheres with tunable interior-cavity sizes were fabricated by using Co nanoparticles as sacrificial templates and varying the stoichiometric ratio of starting material HAuCl4 over the reductants. The formation of these hollow nanostructures is attributed to two subsequent reduction reactions: the initial reduction of HAuCl4 by Co nanoparticles, followed by the reduction by NaBH4. In addition, a thick layer of silica was successfully coated onto the gold hollow nanospheres. These nanostructures are extensively characterized by TEM, XRD, HRTEM, SEM, electron diffraction, energy-dispersive X-ray analysis, and UV-visible absorption spectroscopy. It is evident that the SPR peak locations corresponding to these hollow nanospheres are shifted over a region of more than 100 nm wavelength due to changes of shell thickness, which make these optically active nanostructures of great interest in both fundamental research and practical applications.

Journal Article↗
PubMed2005

Third-order nonlinear optical properties of an ultrathin film containing a porphyrin derivative.

An ultrathin nanoscopic multilayer film has been fabricated through the electrostatic layer-by-layer self-assembly of negatively charged 5,10,15,20-tetrakis(3,4,5-trihydroxyphenyl)porphyrin (DHP) and oppositely charged polyethylenimine (PEI). UV-vis spectra showed a continuous and uniform deposition process of PEI and DHP. The film structure was characterized by small-angle X-ray diffraction measurement and AFM images. The nonlinear optical properties of ultrathin film were studied by Z-scan technique with laser duration of 8 ns at a wavelength of 532 nm. The film sample exhibited strong nonlinear saturated absorption and a self-defocusing effect. The nonlinear absorption coefficient and refractive index of the self-assembly ultrathin film are -9.7 x 10(-5) m/W and -7.56 x 10(-12) m(2)/W, respectively.

Journal Article↗
PubMed2005

Electrochemical ESR and voltammetric studies of lithium ion pairing with electrogenerated 9,10-anthraquinone radical anions either free in acetonitrile solution or covalently bound to multiwalled carbon nanotubes.

The influence of lithium ion pairing on the voltammetric reduction of anthraquinone in acetonitrile is reported. On gold electrodes, the single electron reduction generates a radical anion which forms a complex with lithium cations from the electrolyte. In situ ESR studies support this finding, and signal intensity measurements are used to estimate a value for the complexation equilibrium constant. Values calculated were of the of the order of 6000 mol(-1) dm3. Potential shift measurements and Digisim modeling are shown to be in support of a complexation mechanism in which a little of the complex precipitates on the electrode surface. The effect of lithium ion pairing is also demonstrated for the case in which 1-anthraquinonyl groups are covalently attached to multiwalled carbon nanotubes abrasively immobilized on a basal plane pyrolytic graphite electrode.

Journal Article↗
PubMed2005

Dyads and triads containing perylenetetracarboxylic diimide and porphyrin: efficient photoinduced electron transfer elicited via both excited singlet states.

Synthesis, characterizations, and photophysical properties of new photoactive dyads and triads containing perylenetetracarboxylic diimide (PIm) and porphyrin (free-base porphyrin (H(2)P) and zinc porphyrin (ZnP)), in which both entities were connected with a short ether bond, were examined with the aim of using these systems for molecular photonics. The porphyrin(P)-PIm systems absorbed strongly across the visible region, which greatly matched the solar spectrum. The geometric and electronic structures of the dyads and triads were probed using density function theory method at the B3LYP/3-21G level. It was revealed that the majority of the highest-occupied molecular orbital was located on the porphyrin entity, while the lowest-unoccupied molecular orbitals were entirely on the PIm entity. The excited-state electron-transfer processes were monitored by both steady-state and time-resolved emission as well as transient-absorption techniques in polar solvent benzonitrile. Upon excitation of the P (H(2)P and ZnP) moieties, efficient fluorescence quenching of the P moiety was observed, suggesting that the main quenching paths involved charge separation from the excited singlet porphyrin ((1)P) to the PIm moiety. Upon excitation of the PIm moiety, fluorescence quenching of the (1)PIm moiety was also observed. The nanosecond transience of spectra in near-IR region revealed the charge separation process from the P moieties to the PIm moiety via their excited singlet states. The lifetimes of the charge-separated states were evaluated to be 7-14 ns, depending on the solvent polarity. Photosensitized electron mediation systems were also revealed in the presence of methyl viologen and sacrificial electron donor.

Journal Article↗
PubMed2005

Autosomal dominant cone dystrophy caused by a novel mutation in the GCAP1 gene (GUCA1A).

PURPOSE: To describe the clinical features and genetic analysis of a family with an autosomal dominant cone dystrophy (adCD). METHODS: Selected members of a family with an autosomal dominant cone dystrophy underwent ophthalmic evaluation. Blood samples were obtained, genomic DNA was isolated, and genomic fragments were amplified by PCR. Linkage to locus D6S1017 was established. DHPLC mutational analysis and direct sequencing were used to identify a mutation in GUCA1A, the gene encoding the guanylate cyclase activating protein 1 (GCAP1). RESULTS: Of 24 individuals who are at risk of the disease in a five generation family, 11 members were affected. Clinical presentations included photophobia, color vision defects, central acuity loss, and legal blindness with advanced age. The disease phenotype was observed in the second and third decades of life and segregated in an autosomal dominant fashion. An electroretinogram performed on one proband revealed profoundly subnormal and prolonged photopic and flicker responses, but preserved scotopic ERGs, consistent with a cone dystrophy. Mutational analysis and direct sequencing revealed a C451T transition in GUCA1A, corresponding to a novel L151F mutation in GCAP1. Like the E155G mutation, this mutation occurs in the EF4 hand domain, a region of GCAP1 critical in conferring calcium sensitivity to the protein. The leucine at this position is highly conserved among vertebrate guanylate cyclase activating proteins. CONCLUSIONS: A novel L151F missense mutation in the EF4 high affinity Ca2+ binding site of GCAP1 is linked to adCD in a large pedigree. The cone dystrophy in this family shares clinical and electrophysiologic characteristics with other previously described adCD caused by mutations in GUCA1A.

Adult↗
PubMed2005

Activity-dependent long-term potentiation of intrinsic excitability in hippocampal CA1 pyramidal neurons.

The efficiency of neural circuits is enhanced not only by increasing synaptic strength but also by increasing intrinsic excitability. In contrast to the detailed analysis of long-term potentiation (LTP), less attention has been given to activity-dependent changes in the intrinsic neuronal excitability. By stimulating hippocampal CA1 pyramidal neurons with synaptic inputs correlating with postsynaptic neuronal spikes, we elicited an LTP of intrinsic excitability (LTP-IE) concurring with synaptic LTP. LTP-IE was manifested as a decrease in the action potential threshold that was attributable to a hyperpolarized shift in the activation curve of voltage-gated sodium channels (VGSCs) rather than activity-dependent changes in synaptic inputs or A-type K+ channels. Cell-attached patch recording of VGSC activities indicated such an activity-dependent change in VGSCs. Induction of LTP-IE was blocked by the NMDA receptor antagonist APV, intracellular BAPTA, the CaM kinase inhibitors KN-62 and autocamtide-2-related inhibitory peptide, and the protein synthesis inhibitors emetine and anisomycin. The results suggest that induction of LTP-IE shares a similar signaling pathway with the late phase of synaptic LTP and requires activation of the NMDA glutamate receptor subtype, Ca2+ influx, activity of CaM kinase II, and function of the protein synthesis. This new form of hippocampal neuronal plasticity could be a cellular correlate of learning and memory besides synaptic LTP.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗