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Biomedical subjects

Qiang Fu

Publications and source records attributed to Qiang Fu.

At least 55 records · Page 3Linked to original sources
PubMed2005

Proteomic analysis and extensive protein identification from dry, germinating Arabidopsis seeds and young seedlings.

Proteins accumulated in dry, stratified Arabidopsis seeds or young seedlings, totaled 1100 to 1300 depending on the time of sampling, were analyzed by using immobilized pH gradient 2-DE gel electrophoresis. The molecular identities of 437 polypeptides, encoded by 355 independent genes, were determined by MALDI-TOF or TOF-TOF mass spectrometry. In the sum, 293 were present at all stages and 95 were accumulated during the time of radicle protrusion while another 18 appeared in later stages. Further analysis showed that 226 of the identified polypeptides could be located in different metabolic pathways. Proteins involved in carbohydrate, energy and amino acid metabolism constituted to about 1/4, and those involved in metabolism of vitamins and cofactors constituted for about 3 % of the total signal intensity in gels prepared from 72 h seedlings. Enzymes related to genetic information processing increased very quickly during early imbibition and reached highest level around 30 h of germination.

Arabidopsis↗
PubMed2005

Bright infrared emission from electrically induced excitons in carbon nanotubes.

We used the high local electric fields at the junction between the suspended and supported parts of a single carbon nanotube molecule to produce unusually bright infrared emission under unipolar operation. Carriers were accelerated by band-bending at the suspension interface, and they created excitons that radiatively recombined. This excitation mechanism is approximately 1000 times more efficient than recombination of independently injected electrons and holes, and it results from weak electron-phonon scattering and strong electron-hole binding caused by one-dimensional confinement. The ensuing high excitation density allows us to observe emission from higher excited states not seen by photoexcitation. The excitation mechanism of these states was analyzed.

Journal Article↗
PubMed2005

Identification of neuropeptides from the decapod crustacean sinus glands using nanoscale liquid chromatography tandem mass spectrometry.

Neurosecretory systems are known to synthesize and secrete a diverse class of peptide hormones which regulate many physiological processes. The crustacean sinus gland (SG) is a well-defined neuroendocrine site that produces numerous hemolymph-borne agents including the most complex class of endocrine signaling molecules--neuropeptides. As an ongoing effort to define the peptidome of the crustacean SG, we determine the neuropeptide complements of the SG of the Jonah crab, Cancer borealis, and the Maine lobster, Homarus americanus, using nanoflow liquid chromatography electrospray ionization quadrupole time-of-flight (ESI-QTOF) MS/MS. Numerous neuropeptides were identified, including orcokinins, orcomyotropin, crustacean hyperglycemic hormone (CHH), CHH precursor-related peptides (CPRPs), red pigment concentrating hormone (RPCH), beta-pigment dispersing hormone (beta-PDH), proctolin and HL/IGSL/IYRamide. Among them, two novel orcokinins were de novo sequenced from the SG of H. americanus. Three CPRPs including a novel isoform were sequenced in H. americanus. Four new CPRPs were sequenced from the SG of C. borealis. Our results show that structural polymorphisms in CPRPs (and thus the CHH precursors) are common in Dendrobranchiata as well as in Pleocyemata. The evolutionary relationship between the CPRPs is also discussed.

Amino Acid Sequence↗
PubMed2005

Scattering and absorption property database for nonspherical ice particles in the near- through far-infrared spectral region.

The single-scattering properties of ice particles in the near- through far-infrared spectral region are computed from a composite method that is based on a combination of the finite-difference time-domain technique, the T-matrix method, an improved geometrical-optics method, and Lorenz-Mie theory. Seven nonspherical ice crystal habits (aggregates, hexagonal solid and hollow columns, hexagonal plates, bullet rosettes, spheroids, and droxtals) are considered. A database of the single-scattering properties for each of these ice particles has been developed at 49 wavelengths between 3 and 100 microm and for particle sizes ranging from 2 to 10,000 microm specified in terms of the particle maximum dimension. The spectral variations of the single-scattering properties are discussed, as well as their dependence on the particle maximum dimension and effective particle size. The comparisons show that the assumption of spherical ice particles in the near-IR through far-IR region is generally not optimal for radiative transfer computation. Furthermore, a parameterization of the bulk optical properties is developed for mid-latitude cirrus clouds based on a set of 21 particle size distributions obtained from various field campaigns.

Journal Article↗
PubMed2005

Effects of nano HAP on biological and structural properties of glass bone cement.

A novel type of glass-based nanoscale hydroxyapatite (HAP) bioactive bone cement (designed as GBNHAPC) was synthesized by adding nanoscale hydroxyapatite crystalline (20-40 nm), into the self-setting glass-based bone cement (GBC). The inhibition rate of nanoscale HAP and micron HAP on osteosarcoma U2-OS cells was examined. The effects of nanoscale HAP on the crystal phase, microstructure and compressive strength of GBNHAPC were studied, respectively. It was concluded that nanoscale HAP could inhibit the cell proliferation, whereas micron HAP could not, and that nanoscale HAP could be dispersed in the cement evenly and the morphology did not change significantly after a longer immersion time. XRD and FTIR results show nanoscale HAP did not affect the setting reaction of the cement. Furthermore, GBNHAPC had a higher compressive strength (92.6 +/- 3.8 MPa) than GBC (80.1 +/- 3.0 MPa). It was believed that GBNHAPC might be a desirable biomaterial that could not only fill bone defects but also inhibit cancer cell growth.

Bone Cements↗
PubMed2005

Integrated single-walled carbon nanotube/microfluidic devices for the study of the sensing mechanism of nanotube sensors.

A method to fabricate integrated single-walled carbon nanotube/microfluidic devices was developed. This simple process could be used to directly prepare nanotube thin film transistors within the microfluidic channel and to register SWNT devices with the microfludic channel without the need of an additional alignment step. The microfluidic device was designed to have several inlets that deliver multiple liquid flows to a single main channel. The location and width of each flow in the main channel could be controlled by the relative flow rates. This capability enabled us to study the effect of the location and the coverage area of the liquid flow that contained charged molecules on the conduction of the nanotube devices, providing important information on the sensing mechanism of carbon nanotube sensors. The results showed that in a sensor based on a nanotube thin film field effect transistor, the sensing signal came from target molecules absorbed on or around the nanotubes. The effect from adsorption on metal electrodes was weak.

Adsorption↗
PubMed2005

Metal/oxide interfacial reactions: Oxidation of metals on SrTiO3 (100) and TiO2 (110).

We studied chemical reactions between ultrathin metal films (Al, Cr, Fe, Mo) and single-crystal oxides (SrTiO3 (100), TiO2 (110)) with X-ray photoelectron spectroscopy (XPS). The work function of the metal and the electron density in the oxide strongly influence the reaction onset temperature (T(RO)), where metal oxidation is first observed, and the rate of metal oxidation at the metal/oxide interfaces. The Fermi levels of the two contacting phases affect both the space charges formed at the interfaces and the diffusion of ionic defects across the interfaces. These processes, which determine metal oxidation kinetics at relatively low temperatures, can be understood in the framework of the Cabrera-Mott theory. The results suggest that the interfacial reactivity is tunable by modifying the Fermi level (E(F)) of both contacting phases. This effect is of great technological importance for a variety of devices with heterophase boundaries.

Journal Article↗
PubMed2005

IL-6 is not required for parathyroid hormone stimulation of RANKL expression, osteoclast formation, and bone loss in mice.

Continuous elevation of parathyroid hormone (PTH) increases osteoclast precursors, the number of osteoclasts on cancellous bone, and bone turnover. The essential molecular mediators of these effects are controversial, however, and both increased receptor activator of NF-kappaB ligand (RANKL) and IL-6 have been implicated. The goal of these studies was to determine whether continuous elevation of endogenous PTH alters IL-6 gene expression in vivo and whether IL-6 is required for PTH-induced bone loss. To accomplish this, we generated transgenic mice harboring a luciferase reporter gene under the control of IL-6 gene regulatory regions to allow accurate quantification of IL-6 gene activity in vivo. In these mice, induction of secondary hyperparathyroidism using a calcium-deficient diet did not alter IL-6-luciferase transgene expression, whereas RANKL mRNA expression was elevated in bone tissue. Moreover, secondary hyperparathyroidism induced an equivalent amount of bone loss in wild-type and IL-6-deficient mice, and PTH elevated RANKL mRNA and osteoclast formation to the same extent in bone marrow cultures derived from wild-type and IL-6-deficient mice. These results demonstrate that IL-6 is not required for the osteoclast formation and bone loss that accompanies continuous elevation of PTH.

Absorptiometry, Photon↗
PubMed2005

Mass spectrometric characterization of crustacean hyperglycemic hormone precursor-related peptides (CPRPs) from the sinus gland of the crab, Cancer productus.

Crustacean hyperglycemic hormone (CHH) precursor-related peptides (CPRPs) are produced during the proteolytic processing of CHH preprohormones. Currently, the physiological roles played by CPRPs are unknown. Due to their large size, direct mass spectrometric sequencing of intact CPRPs is difficult. Here, we describe a novel strategy for sequencing Cancer productus CPRPs directly from a tissue extract using nanoflow liquid chromatography coupled to quadrupole time-of-flight tandem mass spectrometry. Four novel CPRPs were characterized with the aid of MS/MS de novo sequencing of 27 truncated CPRP peptides. Extensive modifications (methionine oxidation and carboxy-terminal methylation) were identified in both the full-length and truncated peptides. To investigate the origin of the modifications and truncations, a full-length CPRP was synthesized and subjected to the same storage and extraction protocols used for the characterization of the native peptides. Here, some methionine oxidation was seen, however, no methylation or truncation was evident suggesting much of the chemical complexity seen in the native CPRPs is unlikely due to a sample preparation artifact. Collectively, our study represents the most complete characterization of CPRPs to date and provides a foundation for future investigation of CPRP function in C. productus.

Animals↗
PubMed2005

PDMS microfludic device for optical detection of protein immunoassay using gold nanoparticles.

A simple but highly specific immunoassay system for goat anti-human IgG has been developed using gold nanoparticles and microfluidic techniques. The assay is based on the deposition of gold nanoparticles that are coated with protein antigens in the presence of their corresponding antibodies to microfluidic channel surface. The effects of time accumulation, the flow velocity, and the concentration of antibodies to the red light absorption percentage (RAP) of deposition were investigated with an ordinary optical microscope. By controlling the reaction time and flow velocity, a dynamic range of 3 orders of magnitude and a detection sensitivity of 10 ng ml(-1) of goat anti-human IgG were achieved. Because of its simplicity and flexibility, this new technique should be useful for fast, highthroughput screening of antibodies in clinical diagnostic applications.

Animals↗
PubMed2005

Effects of ionic surfactant adsorption on single-walled carbon nanotube thin film devices in aqueous solutions.

Field-effect transistors were fabricated using high-density single-walled carbon nanotube (SWNT) thin films directly grown on suitable substrates. Such approach eliminated the variations of device behaviors in individual SWNT devices by utilizing a large number of SWNTs in each device. We have found that the behaviors of such devices are closely related to the surface charge densities around SWNTs in aqueous solutions. Adsorption of ionic surfactants on the surface could significantly modulate the device characteristics, which could be detected by measuring the conductance of the devices. The devices could be tuned to be sensitive to either anionic or cationic surfactants by tailoring the surface properties of SiO(2) substrates around SWNTs. This effect could be potentially used to design chemical and biological sensors.

Adsorption↗
PubMed2005

Metal-oxide interfacial reactions: encapsulation of Pd on TiO2 (110).

The model system Pd/TiO2 (110) was used to evaluate the correlation between metal encapsulation and electronic structure of TiO2 crystals. We observed encapsulation of Pd clusters supported on TiO2 crystals, which were heavily Ar+ sputtered, Nb-doped, or reduced by vacuum annealing. In contrast, encapsulation was not observed on unreduced, undoped, or slightly sputtered TiO2 crystals. Our results indicate a strong dependence of the encapsulation process on the electron density in the conduction band of TiO2 and on the space charge formed at Pd/TiO2 interfaces. This behavior is controlled by the initial position of the Fermi energy level (EF) of the metal and the oxide before contact is established. We proved that encapsulation reactions are favored by n-type doping of the oxide and a large work function of the metal. On the basis of this mechanism, we conclude on general trends controlling encapsulation reactions of oxide-supported metal clusters and the strong metal-support interaction (SMSI).

Electrons↗
PubMed2005

Hypoxia suppresses the production of matrix metalloproteinases and the migration of human monocyte-derived dendritic cells.

As most solid tumors are hypoxic, dendritic cells (DC) in solid tumors are also exposed to hypoxia. While many adaptation responses of tumor cells to hypoxia are known, it is yet to be determined how hypoxia affects the functions of DC. To explore the effects of hypoxia on the functions of DC, we compared the expression of surface markers, cytokines, chemokine receptors and matrix metalloproteinases (MMP) of human monocyte-derived DC (hmDC) differentiated under hypoxia to those differentiated under normoxia. Both groups of hmDC expressed similar levels of surface markers and cytokines. However, expression of MMP-9 and membrane type-1-MMP, as well as migrating activity, was significantly suppressed in hmDC differentiated under hypoxia compared with their normoxia counterparts. We also demonstrated that trichostatin A restored the production of MMP-9 in hmDC, under hypoxia. Collectively, our findings show that a hypoxic microenvironment suppresses the production of MMP in hmDC, most probably through the deacetylation of promoter regions of MMP, thus suppressing the migrating activity of hmDC. Our results suggest that the hypoxic microenvironment in solid tumor tissues may suppress the function of DC.

Biomarkers↗
PubMed2005

Change of TH1/TH2 cytokine equilibrium in rats with severe sepsis and therapeutic effect of recombinant interleukin-12 and Shenmai injection.

OBJECTIVE: To evaluate the dynamic change of Th1/Th2 cytokines in serum, peritoneal lavage fluid (PLF) and splenic macrophages (SM) in rats with severe peritonitis, and to observe the therapeutic effects of recombinant interleukin-12 (rIL-2) and Shenmai injection (SMI), a Chinese medicinal preparation. METHODS: Severe peritonitis (SP) model was induced by intraperitoneal injection of E. coli and B. frag, and mild peritonitis (MP) model was induced by cecal ligation and punching. Then the following experiments were done: (1) Survival rates of animals after every 6 hrs in the 72 hrs after modeling were recorded, serum and PLF levels of cytokines, including tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), and interleukin-10 (IL-10), 6 hrs, 12 hrs, 24 hrs and 48 hrs after modeling were measured. (2) Model rats were treated with rIL-12 or SMI, the survival rate was recorded and serum levels of TNF-alpha, INF-gamma, and IL-10 before and after treatment were measured, and (3) amount of these cytokines produced by SM were determined 6 hrs, 12 hrs and 24 hrs after treatment. The survival rates and levels of cytokines were then compared between the groups (model group treated with rIL-12 or SMI, untreated model group, and blank group). RESULTS: Serum and PLF levels of IFN-gamma, TNF-alpha at all the time points in SP rats were significantly lower than those in MP rats while those of IL-10 6 hrs and 12 hrs after modeling were significantly higher in the former than that in the latter (P < 0.05). IFN-gamma secretion of SM in SP rats was significantly higher than that in MP rats 6 hrs after modeling (P < 0.05). Administration of rlL-12 or SMI given before modeling could improve the survival rate of the model rats (P < 0.05) and cause significant increase of the serum level and SM secretion of IFN-gamma. CONCLUSION: Imbalance in promoting/antagonizing inflammatory cytokines and Th2 response dominance appear in SP rats early at the initiating stage, and SM secretion of inflammation promoting factor also reduces. Administration in time of rIL-12 and SMI, may increase the survival rate, and its mechanism may be related with their immuno-stimulating action.

Animals↗
PubMed2005

Anaesthesia record system on handheld computers--pilot experience and uses for quality control and clinical guidelines.

This paper describes a mobile information system to collect patient information for anesthesia quality control. In this system, a mobile database program was designed for use on handheld computers (Pocket PC). This program is used to collect patient data at the bedside on the handhelds, with a daily synchronization of the data between the anaesthesiologists' handhelds with the anaesthesia database. All collected data are later used for quality control analysis. Furthermore, clinical guidelines will be included on these same handhelds. During the pilot phase, data from a sample set of about 300 patients were incorporated. The processes and interfaces of the system are presented in the paper. The current mobile database system has been designed to replace the original paper-based data collection system. The individual anaesthesiologist's handheld synchronizes patient data daily with anaesthesia database center. This information database is analyzed and used not only to give feedback to the individual doctor or center, but also to review the use of the guidelines provided and the results of their utilization.

Anesthesia↗
PubMed2005

Awakening concentration of desflurane is decreased in patients with obstructive jaundice.

BACKGROUND: Some studies suggest that behavioral complications of cholestasis, such as fatigue and pruritus, may be associated with altered neurotransmission in the brain. Because inhaled anesthetics primarily act on ion channels and receptors on the neuronal cell membrane and alter synaptic transmission in the central nervous system, it is possible that altered sensitivity to inhaled anesthetics may occur in cholestatic patients. Therefore, the authors compared the minimum alveolar concentration (MAC)-awake of desflurane in obstructive jaundiced patients with the MACawake in nonjaundiced patients. METHODS: Patients underwent inhalational induction of anesthesia with desflurane. MACawake was determined in each patient by observing the response to a verbal command (open eyes on request). An end-tidal anesthetic concentration was maintained at an initial target level of 1.4% for 15 min before a command. If a positive response was observed, the concentration of desflurane was increased by 0.1% and again kept constant for 15 min. The verbal command was then continued. This process was repeated until an end-tidal concentration was reached at which the patient did not respond to command. The anesthetic concentration midway between the value permitting the response and that just preventing the response was defined as MACawake for each patient. RESULTS: The MACawake of desflurane for patients with obstructive jaundice (1.78 +/- 0.19%) was significantly less than those observed for the control group (2.17 +/- 0.25%; P < 0.001) and correlated significantly with serum total bilirubin (r = -0.67, P = 0.0004). CONCLUSIONS: The MACawake of desflurane is reduced in obstructive jaundiced patients compared with nonjaundiced controls.

Aged↗
PubMed2005

Heritability of SF-36 among middle-age, middle-class, male-male twins.

OBJECTIVE: We sought to examine the relative importance of genetic and environmental factors for the MOS SF-36; a widely used, valid, and reliable measure of health-related quality of life and to discuss incorporating genetic influences into health services research. DATA SOURCES: Data are from a nationally distributed, nonclinical cohort of 2928 middle age, middle-class, male-male twin members of the Vietnam Era Twin Registry. STUDY DESIGN: This was a secondary data analysis, classic twin heritability analysis. DATA COLLECTION: A telephone survey was used to collect information on alcohol-related problems and health services use, including the SF-36. PRINCIPAL FINDINGS: Variance component analyses indicated that additive genetic factors accounted for 17% to 33% of the variance for each of the 8 domains of the SF-36. Shared environment accounted for 0% to 12% of the variance for each domain, with the majority of variance for each domain accounted for by nonshared, or unique environment and error. Physical and mental health summary measures indicated that approximately one-third of the variance was accounted for by additive genetic factors and the remainder accounted for by nonshared environment and error. Clinical condition, history of alcohol dependence, had a small-but-significant influence for all domains. Including condition proved to be a better-fitting model. However, confidence intervals temper uniform statistical significance for genetic factors. CONCLUSIONS: This study assessed the heritability of the SF-36 in a nonclinical, community sample of middle age, middle-class all-male twins. The moderate genetic effects on SF-36 domain and summary measures are new findings and thus may affect interpretations of SF-36 as a measure of health-related quality of life. Ideally, trait-based measures should identify genetic sources of variation and thus help understand any bias of the true effects of SF-36. Still the majority of variance is accounted for by nonshared or unique environmental factors and error. By extension, increased understanding of the importance of genetic and environmental factors that influence either predictors or outcomes of interest will expand the level of scientific debate in health services research and improve predictability.

Adult↗