Electrochemical hydrogen storage in single-walled carbon nanotube paper

Single-walled carbon nanotube (SWNT) papers were successfully prepared by dispersing SWNTs in Triton X-100 solution, then filtered by PVDF membrane (0.22 microm pore size). The electrochemical behavior and the reversible hydrogen storage capacity of single-walled carbon nanotube (SWNT) papers have been investigated in alkaline electrolytic solutions (6 N KOH) by cyclic voltammetry, linear micropolarization, and constant current charge/discharge measurements. The effect of thickness and the addition of carbon black on hydrogen adsorption/desorption were also investigated. It was found that the electrochemical charge-discharge mechanism occurring in SWNT paper electrodes is somewhere between that of carbon nanotubes (physical process) and that of metal hydride electrodes (chemical process), and consists of a charge-transfer reaction (Reduction/Oxidation) and a diffusion step (Diffusion).

Enhancement of ionic conductivity of PEO based polymer electrolyte by the addition of nanosize ceramic powders

The ionic conductivity of polyethylene oxide (PEO) based solid polymer electrolytes (SPEs) has been improved by the addition of nanosize ceramic powders (TiO2 and AL2O3). The PEO based solid polymer electrolytes were prepared by the solution-casting method. Electrochemical measurement shows that the 10 wt% TiO2 PEO-LiClO4 polymer electrolyte has the best ionic conductivity (about 10(-4) S cm(-1) at 40-60 degrees C). The lithium transference number of the 10 wt% TiO2 PEO-LiClO4 polymer electrolyte was measured to be 0.47, which is much higher than that of bare PEO polymer electrolyte. Ac impedance testing shows that the interface resistance of ceramic-added PEO polymer electrolyte is stable. Linear sweep voltammetry measurement shows that the PEO polymer electrolytes are electrochemically stable in the voltage range of 2.0-5.0 V versus a Li/Li+ reference electrode.

The requirements and mechanism for capsid assembly and budding of bovine foamy virus

Little is known about assembly of non-primate foamy virus (FV) such as bovine foamy virus (BFV). To help determine the requirements for assembly of BFV, we constructed BFV-Gag expression plasmids containing all or part of the gag gene, with or without modification by addition of myristate (Myr). Each construct was transfected alone, and with pFenv, into Sf-9 insect cells. The results showed that only the entire Gag could transit through nucleus, which is required for BFV viral assembly in the cytoplasm. Unlike other retroviruses (but like primate foamy viruses), BFV requires the coexpression of the Env protein for viral particle budding. In the case of BFV, this occurs at the plasma membrane rather than the endoplasmic reticulum (ER), due to lack of a functional ER retrieval signal (ERRS). The results also showed that addition of a Myr-membrane targeting signal to the C-terminus of Gag could restore the budding from plasma membrane, implying that Myr-membrane targeting signal could substitute for Env protein in budding.

Observation of a threshold enhancement in the plambda invariant-mass spectrum

An enhancement near the m(p)+M(Lambda) mass threshold is observed in the combined pLambda and pLambda invariant-mass spectrum from J/psi-->pK(-)Lambda;+c.c. decays. It can be fit with an S-wave Breit-Wigner resonance with a mass m=2075+/-12(stat)+/-5(syst) MeV and a width of Gamma=90+/-35(stat)+/-9(syst) MeV; it can also be fit with a P-wave Breit-Wigner resonance. Evidence for a similar enhancement is also observed in psi(')-->pK(-)Lambda;+c.c. decays. The analysis is based on samples of 5.8x10(7)J/psi and 1.4x10(7)psi(') decays accumulated in the BES II detector at the Beijing Electron-Positron Collider.

Dewetting of conducting polymer inkjet droplets on patterned surfaces

The manufacture of high-performance electronic devices with micrometre or even submicrometre dimensions by solution processing and direct printing, requires the ability to control accurately the flow and spread of functional liquid inks on surfaces. This can be achieved with the help of surface-energy patterns causing inks to be repelled and dewetted from pre-defined regions of the substrate. To exploit this principle for the fabrication of submicrometre device structures, a detailed understanding of the factors causing ink droplets to dewet on patterned surfaces is required. Here, we use hydrophobic surface-energy barriers of different geometries to study the influence of solution viscosity, ink volume, and contact angle on the process of dewetting of inkjet-printed droplets of a water-based conducting polymer. We demonstrate polymer field-effect transistor devices with channel length of 500 nm fabricated by surface-energy-assisted inkjet printing.

Observation of the decay psi(2S)-->K0SK0L

The decay psi(2S)-->K(0)(S)K(0)(L) is observed using psi(2S) data collected with the Beijing Spectrometer at the Beijing Electron-Positron Collider; the branching fraction is determined to be B(psi(2S)-->K(0)(S)K(0)(L))=(5.24+/-0.47+/-0.48)x10(-5). Compared with J/psi-->K(0)(S)K(0)(L), the psi(2S) branching fraction is enhanced relative to the prediction of the perturbative QCD "12%" rule. The result, together with the branching fractions of psi(2S) decays to other pseudoscalar meson pairs (pi(+)pi(-) and K+K-), is used to investigate the relative phase between the three-gluon and the one-photon annihilation amplitudes of psi(2S) decays.

Inhibition of protein phosphatase 2A- and protein phosphatase 1-induced tau hyperphosphorylation and impairment of spatial memory retention in rats

Tau hyperphosphorylation leads to formation of paired helical filament/neurofibrillary tangles, the hallmark lesion seen in Alzheimer's disease (AD) brain. An imbalanced regulation in protein kinases and protein phosphatases in the affected neurons is proposed to be a reasonable causative factor to the disease process. To verify the hypothesis, we have injected in the present study calyculin A, a potent and specific inhibitor of protein phosphatase (PP) 2A and PP1, into rat hippocampus bilaterally, thus reproduced an Alzheimer's-like deficiency in dephosphorylation system. It was found that calyculin A-injected rats developed lesions in spatial memory retention in Morris water maze test. At mean time, tau was hyperphosphorylated at Ser396/Ser404 (PHF-1) and Ser-262/Ser-356 (12E8) sites determined both by immunohistochemistry and Western blot. It is implicated that (1) PP2A and PP1 participate in the in vivo regulation of tau phosphorylation, and down-regulation of the two phosphatases will result in tau hyperphosphorylation; (2) hyperphosphorylation of tau at PHF-1 and 12E8 sites might be crucial to affect spatial memory in AD.

Observation of a near-threshold enhancement in the pp mass spectrum from radiative J/psi-->gammapp decays

We observe a narrow enhancement near 2m(p) in the invariant mass spectrum of pp pairs from radiative J/psi-->gammapp decays. No similar structure is seen in J/psi-->pi(0)pp decays. The results are based on an analysis of a 58 x 10(6) event sample of J/psi decays accumulated with the BESII detector at the Beijing electron-positron collider. The enhancement can be fit with either an S- or P-wave Breit-Wigner resonance function. In the case of the S-wave fit, the peak mass is below 2m(p) at M=1859(+3)(-10) (stat)+5-25(syst) MeV/c(2) and the total width is Gamma<30 MeV/c(2) at the 90% confidence level. These mass and width values are not consistent with the properties of any known particle.

Measurements of the cross section for e(+)e(-) --> hadrons at center-of-mass energies from 2 to 5 GeV

We report values of R = sigma(e(+)e(-)-->hadrons)/sigma(e(+)e(-)-->mu(+)mu(-)) for 85 center-of-mass energies between 2 and 5 GeV measured with the upgraded Beijing Spectrometer at the Beijing Electron-Positron Collider.

Measurements of cosmic-ray low-energy antiproton and proton spectra in a transient period of solar field reversal

The energy spectra of cosmic-ray low-energy antiprotons ( *p's) and protons ( p's) have been measured by BESS in 1999 and 2000, during a period covering reversal at the solar magnetic field. Based on these measurements, a sudden increase of the *p/p flux ratio following the solar magnetic field reversal was observed, and it generally agrees with a drift model of the solar modulation.

[Comparative study of the expression and phosphorylation of neurofilament proteins of brain gray matter in Alzheimer's disease]

OBJECTIVE

To explore the role of abnormal modification of neurofilament proteins (NFPs) in the pathogenesis of Alzheimer disease (AD), and the characteristics of NFPs in distribution and solubility.

METHOD

Ultra-centrifugation and Western blot were utilized to isolate and analyze NF subunits. Ultra-centrifugation and Western blot were utilized to observe the effect of abnormal modification of neurofilament proteins (NFPs) on the characteristics of NFPs in distribution and solubility in the pathogenesis of Alzheimer disease.

RESULTS

In human brain gray matter, NF subunits were mainly detected in particular fraction. Compared with Huntington's disease (HD), the content of NF subunits was increased in AD brain gray matter and the increased level of NF-H and NF-M were mainly in abnormal hyper-phosphorylate form.

CONCLUSION

Abnormal phosphorylation and accumulation of NFPs are involved in pathology of AD brain.

[Alzheimer-like protein phosphatase deficiency leads to abnormal phosphorylation and accumulation of neurofilaments]

OBJECTIVE

To explore the effect of Alzheimer-like protein phosphatase deficiency on neurofilament phosphorylation.

METHODS

Cell culture, light microscopy, immunocytochemistry and biochemistry techniques were used to make a phosphatase deficient cell model, to detect cell morphology, neurofilament phosphorylation and distribution, cell viability and activity.

RESULTS

Non-phosphorylated neurofilament recognized by SMI32 was detected both in cell body and cell processes, it was extremely enriched in cell bodies; Phosphorylated neurofilament bound to SMI34 was mainly determined in cell processes and cell surface. After treatment with okadaic acid (OA), non-phosphorylation-dependent antibodies SMI32 staining was significantly decreased in the cell body, whereas phosphorylated neurofilament reacted with SMI34 was strikingly increased in immunocytochemistry and Western blot, and prominently accumulated to the same cell location. Accompanied with hyper-phosphorylation and accumulation of neurofilament, dose dependent cell toxicity was observed by okadaic acid treatment.

CONCLUSION

Deficiency in protein phosphatase induces in neuroblastoma cell line, neurofilament phosphorylation and accumulation, which is involved in Alzheimer neurofibrillary degeneration.

Wavelets and imaging informatics: a review of the literature

Modern medicine is a field that has been revolutionized by the emergence of computer and imaging technology. It is increasingly difficult, however, to manage the ever-growing enormous amount of medical imaging information available in digital formats. Numerous techniques have been developed to make the imaging information more easily accessible and to perform analysis automatically. Among these techniques, wavelet transforms have proven prominently useful not only for biomedical imaging but also for signal and image processing in general. Wavelet transforms decompose a signal into frequency bands, the width of which are determined by a dyadic scheme. This particular way of dividing frequency bands matches the statistical properties of most images very well. During the past decade, there has been active research in applying wavelets to various aspects of imaging informatics, including compression, enhancements, analysis, classification, and retrieval. This review represents a survey of the most significant practical and theoretical advances in the field of wavelet-based imaging informatics.

Multiple forms of phosphatase from human brain: isolation and partial characterization of affi-gel blue nonbinding phosphatase activities

Phosphatases extracted from a human brain were resolved into two main groups, namely affi-gel blue-binding phosphatases and affi-gel blue-nonbinding phosphatases. Affi-gel blue binding phosphatases were further separated into four different phosphatase activities, designated P1-P4, and described previously. In the present study we describe the affi-gel blue-nonbinding phosphatases which were separated into seven different phosphatase activities, designated P5-P11 by poly-(L-lysine)-agarose and aminohexyl Sepharose 4B chromatographies. These seven phosphatase activities were active toward nonprotein phosphoester. P7-P11 and to some extent P5 could also dephosphorylate a phosphoprotein. They displayed different enzyme kinetics. On the basis of activity peak, the apparent molecular mass as estimated by Sephadex G-200 column chromatography for P5 was 49 kDa; P6, 32 kDa; P7, 150 kDa; P8, 250 kDa; P9, 165 kDa; P10, 90 kDa and P11, 165 kDa. Immunoblot analysis indicated that P8-P11 may belong to PP2B family, whereas P7 may associate with PP2A. The phosphatases P7-P11 were found to be effective in the dephosphorylation of Alzheimer's disease abnormally hyperphosphorylated tau. The resulting dephosphorylated tau regained its activity in promoting the microtubule assembly, suggesting that P7-P11 might regulate the phosphorylation of tau protein in the brain.

[The role of neuroimmunoregulation mobilized by enhancing immunologic function via hou hai acupoint antigen injection]

OBJECTIVE

To study the mechanism of neuroimmunoregulation which is triggered by enhancing immunologic function via Hou Hai acupoint antigen injection.

METHODS

Immunohistochemical method, immunofluorometric method and RT-PCR were used to examine the different distribution of cytokine immunopositive cells in the brain and expression of cytokines in the spleen of the human IgG sensitized rats received acupoint, subcutaneous and normal rats antigen injections.

RESULTS

In the areas of lateral hypothalamic nucleus (LH) and amygdaloid nuclear complex (AA), the distribution of cytokines immunopositive cells with acupoint injection group was significantly increased more than that in the subcutaneous injection group. But the expression of cytokines immunopositive cells both by the acupoint injection and the subcutaneous injection groups reached their peak value in similar time. Double-labelling results showed that the cytokine immunopositive cells were neurons. In the spleens, the expressions of cytokines, IL-2 and IFN, were significantly increased by acupoint injection more than subcutaneous injection.

CONCLUSIONS

The time course of neuroimmunoregulation is similar in the immunized rats via both acupoint injection and subcutaneous injection of antigens. But the activity of neuroimmunoregulation is not the same in acupoint and subcutaneous injection groups. Neurons of the LH and AA are the main source of the neuroimmunomodulators. The effect of enhancing immunologic function via Hou Hai acupoint injection is may be more efficient to mobilize the activity of neuroimmunoregulation of immune-associated brain region than modulation of the immune system.

Anti-nociceptive effect of neuropeptide Y in periaqueductal grey in rats with inflammation

Experimental inflammation was induced by subcutaneous injection of carrageenan into the left hindpaw of rats. Intra-periaqueductal grey (PAG) injection of 0.02 or 0.1 nmol of neuropeptide Y (NPY), but not 0.004 nmol, induced significant increases in hindpaw withdrawal latency (HWL) to thermal and mechanical stimulation in rats with inflammation. Furthermore, the anti-nociceptive effect of NPY was blocked partly by following intra-PAG injection of the Y1 receptor antagonist NPY28-36. The results demonstrated that NPY plays an anti-nociceptive role in PAG in rats with inflammation, in which Y1 receptor is involved.

Mechanism of neurofibrillary degeneration and pharmacologic therapeutic approach

Neurofibrillary degeneration is a key histopathological brain lesion of Alzheimer disease (AD) and related neurodegenerative disorders such as frontotemporal dementia and Parkinsonism linked to chromosome 17 (FTDP-17), commonly referred to as tauopathies. Microtubule associated protein (MAP) tau, which is a major MAP of a normal mature neuron is abnormally hyperphosphorylated in tauopathies and is the major protein subunit of paired helical filaments (PHF)/straight filaments (SF) which accumulate in the soma (as neurofibrillary tangles) and dystrophic neurites (as neuropil threads and as dystrophic neurites surrounding the beta-amyloid core in neuritic plaques in AD) of the affected neurons. Unlike normal tau which stimulates assembly and stabilizes microtubules, the abnormally hyperphosphorylated tau inhibits assembly and disrupts microtubules. The abnormally hyperphosphorylated tau competes with tubulin/microtubules in associating with normal tau, MAP1 and MAP2. This sequestration of normal MAPs by the abnormal tau results in the breakdown of the microtubules. The association of the abnormal tau with normal tau and not with MAP1 or MAP2 results in the formation of tangles of tau filaments. All these toxic properties of the abnormally hyperphosphorylated tau are eliminated by its enzymatic dephosphorylation. Activities of phosphoseryl/phosphothreonyl protein phosphatases (PP)-2A and PP-1 which can dephosphorylate the abnormal tau to a normal-like state are compromised in AD brain. Dephosphorylation by PP-2A and PP-2B and to a lesser extent by PP-1 restores the normal microtubule assembly promoting activity in AD P-tau in vitro. Neurofibrillary tangles of PHF isolated from AD brain are also dissociated on in vitro dephosphorylation with PP-2A, and the tau released by this treatment can stimulate microtubule assembly. Thus, it appears that the abnormal hyperphosphorylation of tau leads to neurodegeneration through breakdown of the microtubule network and that the abnormal tau on association with normal tau forms neurofibrillary tangles of tau filaments i.e. PHF/SF. Increase in tau phosphatase activity is a promising approach to inhibit neurofibrillary degeneration and thereby the diseases characterized by this lesion.

[Gene cloning, expression and purification of its production of recombinant human superoxide dismutase]

Human SOD cDNA was cloned and constructed an expression plasmid with high sufficient and stabilility expression in E. coli. The rhSOD cDNA was amplified by RT-PCR with the template of the total RNA extracted from human liver tissue. The expression plasmid, pLY-4/rhSOD, containing rhSOD cDNA, was transformed into the E. coli JF1125. The sequence of the cloned rhSOD cDNA was identified with the reported data. The expression level reached to more than 68% of total bacteria proteins; The technology for protein renature and purification was efficiency and fast. The purity of the final products reached more than 98%. The value of bioactivity was determined as 2529 u/mg. This study gave enough support for production of rhSOD by biotechnology.

Purification of a sensory-specific protein of 35 kDa (SSP-35)

Protein purification is a key technique for the identification of novel sensory nerve-specific proteins. A 35 kDa protein, the sensory neuronal specific protein, was isolated and purified from rabbit spinal ganglia and sensory fibers by homogenizing and deriving soluble extracts, followed by ion exchange chromatography using DEAE-Sephacel and gel filtration HPLC. Western blot analysis showed that the protein was present in spinal sensory ganglia but not in spinal motor neurons with anti-rat 35 kDa protein polyclonal antibody. The sensory-specific protein 35 kDa is termed SSP-35 in this paper. We found that the purified SSP-35 promoted axonal growth of the dorsal root ganglia of chick E8 embryos. Our data reveal that the protocol is an effective method for the purification of SSP-35. The protein may not only be a useful marker for sensory neurons, but also a possible tool to study the regeneration and function of sensory neurons.

Antinociceptive effects induced by intra-periaqueductal grey administration of neuropeptide Y in rats

Hindpaw withdrawal latency (HWL) to thermal and mechanical stimulation increased dose-dependently after intra-periaqueductal grey (PAG) injection of neuropeptide Y (NPY). Furthermore, the NPY-induced increases in HWLs were attenuated by intra-PAG injection of the Y1 receptor antagonist NPY28-36. The results demonstrated that NPY plays an important role in antinociception in PAG, in which Y1 receptor is involved in.

[Expression of citrate transporter mRNA in the kidneys of rats with metabolic acidosis]

The purpose of the present study was to examine whether metabolic acidosis affects the expression of rat renal Na(+)/citrate cotransporter. Female Wistar rats were pair-fed with normal rat chow and drinking water (control) or water with 0.28 mol/L NH4Cl (metabolic acidosis). The mRNA of two renal Na(+)/citrate cotransporters, which were respectively expressed on apical and basolateral membrane, were measured by Northern blot with two probes, SDCT1 and SDCT2. Animals were sacrificed on day 1,3 and 7. On the 1st day, the blood plasma HCO(-)3 of acidosis group decreased significantly (P<0.01), but the mRNA abundance did not change. On the 3rd day in the acidosis group, the blood plasma HCO(-)3 increased slightly more than that on the 1st day, but was still significantly lower than that of the control group (P<0.01). Both the probes detected some increase in mRNA of brush border and basolateral Na(+)/citrate cotransporter. On the 7th day, the blood plasma HCO(-)3 of the acidosis group continuously increased and there was no significant difference between the two groups. The abundance of brush border and basolateral Na(+)/citrate cotransporter mRNA increased, but there was no difference between those of the 3rd day and the 7th day. It is concluded that metabolic acidosis can induce increase of Na(+)/citrate cotransporter mRNA, which may be responsible for hypocitraturia.

Pathfinder: multiresolution region-based searching of pathology images using IRM

The fast growth of digitized pathology slides has created great challenges in research on image database retrieval. The prevalent retrieval technique involves human-supplied text annotations to describe slide contents. These pathology images typically have very high resolution, making it difficult to search based on image content. In this paper, we present Pathfinder, an efficient multiresolution region-based searching system for high-resolution pathology image libraries. The system uses wavelets and the IRM (Integrated Region Matching) distance. Experiments with a database of 70,000 pathology image fragments have demonstrated high retrieval accuracy and high speed. The algorithm can be combined with our previously developed wavelet-based progressive pathology image transmission and browsing algorithm and is expandable for medical image databases.

Identification of self-assembly products from N-phosphoamino acids by electrospray ionization mass spectrometry

The self-assembly products of N-(O,O'-diisopropyl)-L-alpha-amino acids in aqueous media, N-(O,O'-diisopropyl)phosphoryl dipeptides and tripeptides, were identified by electrospray ionization mass spectrometry. A stepwise fragmentation of the [M + H](+) ions from the C-terminus of N-phosphopeptides was observed. Copyright 2000 John Wiley & Sons, Ltd.

Electrospray ionization mass spectra of amino acid phosphoramidates of adenosine

Amino acid phosphoramidates of adenosine were synthesized and determined by positive and negative ion electrospray ionization mass spectrometry (ESI-MS) in conjunction with tandem mass spectrometry (MS/MS). The fragmentation pathways were investigated. In the positive ion mass spectra abundant characteristic fragment ions appeared, and many complementary ions were found. In the negative ion mass spectra only a few fragment ions were observed, and most of them contained phosphoryl groups. The results show that ESI-MS is a useful tool for structural determination of amino acid phosphoramidates of nucleosides.