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At least 469 records · Page 26Linked to original sources
PubMed2001

7,8-Dihydropterin-6-carboxylic acid as light emitter of luminous millipede, Luminodesmus sequoiae.

A luminous millipede. Luminodesmus sequoiae, emits light centered at a wavelength of 500 nm. To determine the light emitter of this bioluminescent system, fluorescent compounds were isolated from pulverized cuticles. NMR and MS spectra of these compounds showed them to be pterin derivatives. Furthermore, proton/deuterium (H/D) exchange experiments by ESI-Q-TOF-MS and -MS/MS measurements have proved to be a powerful tool for elucidating these heteroaromatic compounds. Finally, we have concluded that 7,8-dihydropterin-6-carboxylic acid, a new natural product, is the light emitter of Luminodesmus bioluminescence.

Animals↗
PubMed2003

Detection of glucocorticoid-like activity in traditional Chinese medicine used for the treatment of Duchenne muscular dystrophy.

Anecdotal reports of positive influence of certain traditional Chinese medicines on the progression of neuromuscular diseases in general and Duchenne muscular dystrophy (DMD) in particular has raised interest in patient support groups and clinical experts alike. However, clinical signs of steroid-specific side effects in patients treated with a particular form of Chinese medicine raised the concern that they may contain glucocorticoids, which in turn could also explain the mild beneficial effects seen in some of the patients. We have extracted and fractionated capsules containing pulverized Chinese medicine that had been used for the treatment of DMD patients and analyzed their content for glucocorticoid-like activity using promoter-reporter assays. We demonstrate that extracts from this Chinese medicine activate a prototype glucocorticoid-response element, increase the level of utrophin protein in human muscle cells and activate the utrophin promoter A. Based on our bioassays we conclude that this particular Chinese medicine used for the treatment of muscular dystrophy patients contains glucocorticoids as one of its active ingredients.

Animals↗
PubMedDate not supplied

The first international intercomparison of EPR-dosimetry with teeth: first results.

Intercomparison of EPR-dosimetric techniques using tooth enamel had been performed in order to check whether the results produced by different laboratories are consistent and accurate. Participants were supposed to evaluate doses applied to pulverized enamel samples, using routine techniques from their laboratories. The intercomparison has demonstrated a great variety of methods used for dose reconstruction. Peculiarities of experimental approaches are discussed systematically in terms of procedure for recording the EPR-spectra, determination of the amplitude of the radiation induced signal, determination of the dose, and error propagation.

Dental Enamel↗
PubMed2000

Light weight concrete: 226Ra, 232Th, 40K contents and dose reduction assessment

Four types of light weight concrete (LWC) commonly used in Hong Kong, namely, autoclave aerated concrete (plus lime), autoclave aerated concrete (plus Pulverized Fuel Ash or PFA), concrete with synthetic aggregate 'Leca' and concrete with polystyrene bean as aggregate were measured for their 226Ra, 232Th and 40K contents using high-resolution gamma spectrometry. All the radionuclide contents except those for the PFA autoclave aerated concrete were below the world averages of building materials. The Ra-equivalents for these four LWC were 49.6, 249, 122 and 44.2 Bq kg(-1), respectively, and were much smaller than a recommended limit of 370 Bq kg(-1) for construction materials for dwellings. The gamma-dose rate for an indoor environment with partition walls built with LWC was estimated to be about 20 x 10(-8) Gy h(-1), which corresponded to a reduction in the effective dose of about 0.25 mSv y(-1) when compared to that obtained for an indoor environment built with normal concrete (NC) only. The Rn exhalation rates from the three lowest Ra-equivalent LWC were calculated as 0.509, 1.28, and 0.335 mBq m(-2) s(-1), respectively, which corresponded to a reduction in the indoor Rn concentration of around 14 Bq m(-3) and reduction in the tracheobronchial dose reaching 1 mSv y(-1) by using the James lung-dosimetry model, when compared to the case of NC.

Journal Article↗
PubMedDate not supplied

Improved mechanical thrombolysis with the addition of recombinant tissue-type plasminogen activator: in vitro study with use of Cr-51-labeled clots.

PURPOSE: To explore the potential effect of infusion of recombinant tissue-type plasminogen activator (rt-PA) during mechanical thrombolysis. MATERIALS AND METHODS: Clots containing chromium-51-labeled platelets produced from blood from two donors were placed in a solution of rt-PA (1.25 micrograms/mL) or in saline solution and were pulverized with a mechanical thrombolysis catheter. The resultant slurry was passed through a filter with a pore size of 10 microns, and the radioactivity of the clot residue on the filter was measured. For each donor, the percentage of clot remaining was calculated from the residual radioactivity. RESULTS: The mean percentages of clot remaining were 72.0% for clots in saline (n = 10) and 44.4% for clots in rt-PA (n = 10) in donor 1 and 58.9% (n = 14) and 36.4% (n = 14), respectively, for donor 2. In both cases, the mean percentage of clot remaining was significantly lower when mechanical thrombolysis was performed in the presence of rt-PA. CONCLUSION: These results indicate the feasibility of combined pharmacologic and mechanical thrombolysis.

Blood Coagulation↗
PubMedDate not supplied

Massive pulmonary embolism: preliminary results of treatment with the Amplatz thrombectomy device.

PURPOSE: To determine the feasibility of using the Amplatz thrombectomy device (ATD) to treat massive pulmonary embolism (PE). PATIENTS AND METHODS: Five patients (four men, one woman; mean age, 45.2 years) with massive PE underwent mechanical thrombectomy with the ATD, which creates a vortex that pulverizes and recirculates the clots within the pulmonary circulation. The patients were followed up for 7-18 months after thrombectomy. RESULTS: Marked improvement in pulmonary perfusion was observed in three patients at angiography and ventilation-perfusion scanning. No changes could be assessed in one patient who died shortly after the procedure. One patient developed hemoptysis during the procedure, most likely because of a reperfusion syndrome. A reduction in pulmonary artery pressure was observed in only one patient; the remaining patients had increased pressure. The four surviving patients were discharged within 8 days. CONCLUSION: Mechanical thrombectomy with the ATD provides rapid debulking of thrombus in some patients with massive PE and has the potential to improve treatment and outcomes of the most sick patients.

Adult↗
PubMed2002

In situ detection of potassium atoms in high-temperature coal-combustion systems using near-infrared-diode lasers.

Direct tunable diode laser absorption spectroscopy at 769.9 and 767.5 nm was used to measure potassium (K) atom concentrations in situ in the high temperature (up to 1650 K) flue gas of two different pulverized coal dust combustion systems (atmospheric or pressurized (12 bar)). Two laser types (Fabry-Pérot (FP) and vertical-cavity surface-emitting lasers (VCSEL)) were used for the spectrometer and characterized with respect to the magnitude and linearity of their static and dynamic wavelength tuning properties. The wide continuous current-induced tuning range of the VCSEL of 20 cm(-1) (compared to 1 cm(-1) for the FP) make this laser ideal for species monitoring in high pressure processes. Two VCSELs were time-multiplexed to realize the simultaneous detection of the potassium D1 and D2 lines. Several oxygen absorption lines in the A-band, which are in close spectral vicinity of the K lines, were detected simultaneously, showing the possibility of multi-species detection with one laser. Using the FP-DL for the atmospheric process and the VCSEL for the high pressure process, the pressure-dependent coefficients for spectral broadening as well as a shift of the K line in the flue gas were determined to be (0.18 +/- 0.01) and (-0.060 +/- 0.003) cm(-1) per atm (at 1540 K and 11.2 bar). The total width and shift of the D1 line (11.2 bar/1540 K) were 60 and -20 GHz, respectively. The K atom concentration was determined continuously for several days in both plants under various operation conditions. Typical concentrations in the atmospheric plant were around 2 microg m(-3) with a range of 50 ng m(-3)-30 microg m(-3). Averaging 100 scans for each concentration value, we achieved a time resolution of 1.7 s and a detection limit of 10 ng m(-3), which corresponds to a fractional absorption in the 10(-3)-10(-4) range. A strong anti-correlation with the oxygen concentration could be verified. At the 12 bar plant, the concentration was again typically around 2 microg m(-3) but K levels up to 60 microg m(-3) were observed. Here, a strong dependence of the K-signal on the type of fuel could be verified.

Coal↗
PubMed1996

Inhibition of head and neck metastatic and/or recurrent cancer by local administration of multi-cytokine inducer OK-432.

The multi-cytokine inducer OK-432 is a pulverized preparation of the low-virulence SU strain of Streptococcus pyogenes of human origin. A reduction of the tumour mass in the OK-432-injected areas was observed in 11 out of 13 patients with metastatic and/or recurrent head and neck cancer. Complete response (CR), partial response (PR) and minor response (MR) were noted in six, three and two cases respectively. OK-432 local administration therapy could create a new strategy for cancer therapy.

Adult↗
PubMed1993

Determination of methylmercury in fish samples using GC/AA and sodium tetraethylborate derivatization.

A simple technique is described for the rapid determination of methylmercury in fish tissue. Following simple dissolution in methanolic KOH solution, aqueous phase ethylation by derivatization with NaB(C2H5)4, cryogenic trapping on a packed chromatographic column, and GC separation, volatile mercury species are detected by atomic absorption spectrometry. Absolute detection limits are 4 pg of Hg for CH3Hg+ and 75 pg of Hg for labile Hg2+. Concentration detection limits for this optimized procedure are 4 ng of Hg for CH3Hg+ and 75 ng of Hg for labile Hg2+ per gram of pulverized dried fish tissue. Analysis of standard reference materials demonstrates the accuracy, precision, and reproducibility of the analytical method.

Animals↗
PubMed2004

Development of a hyphenated microanalytical system for the investigation of leaching kinetics of heavy metals in environmental samples.

A fast and convenient method for on-line monitoring of the extraction of heavy metals from solid (environmental) matrixes was developed. By the incorporation of microcartridges filled with dried and pulverized solid samples into the conduits of a flow system and appropriate selection of the liquid flowing through the cartridge, information about the degree of leaching and in particular of the kinetics of the leaching process are obtained. The method was optimized for determination of different metals of environmental concern using in-line detection by FAAS and ICPMS.

Environmental Pollutants↗
PubMed2004

Simultaneous quantification of opiates, cocaine, and metabolites in hair by LC-APCI-MS/MS.

A quantitative LC-APCI-MS/MS method for simultaneous measurement of opiates, cocaine, and metabolites in hair was developed and validated. Cocaine and opiates were extracted from pulverized hair via sonication in methanol at 37 degrees C for 3 h. Samples were cleaned up using solid-phase extraction. LC separation was achieved in 20 min with identification and quantification by selected reaction monitoring. Calibration by linear regression analysis utilized deuterated internal standards and a weighting factor of 1/x (R(2) > 0.998). Limits of quantification (LOQ) ranged from 17 to 50 pg/mg for cocaine and metabolites and were 83 pg/mg for opiates. Standard curves were linear from the LOQ to 5000 pg/mg for cocaine and metabolites, except benzoylecgonine (2500 pg/mg). Opiate standard curves were linear from the LOQ to 12500 pg/mg. Accuracy ranged from 84 to 115% for all quantitative analytes. Precision, % relative standard deviation, was less than 11.0% for all analytes. Methanolic sonication produced less than 5% hydrolysis of cocaine and 6-acetylmorphine. The method should be useful for studying cocaine and opiate distribution into hair.

Cocaine↗
PubMedDate not supplied

Conjugation and modeled structure/function analysis of lysozyme on glycine esterified cotton cellulose-fibers.

The antimicrobial activity of lysozyme covalently bound to glycine-derivatized cotton cellulose was assessed in a 96-well format. Lysozyme was immobilized on glycine-bound cotton through a carbodiimide reaction. The attachment to cotton fibers was made through both a single glycine and a glycine dipeptide esterified to cotton cellulose. Higher levels of lysozyme incorporation were evident in the diglycine-linked cotton cellulose samples. The antibacterial activity of the lysozyme-conjugated cotton cellulose against Bacillus subtilis was assessed as a suspension of pulverized cotton fibers in microtiter wells. Inhibition of B. subtilis growth was observed to be optimal within a range of 0.14-0.3 mM (equivalent to 4-20 mg of lysozyme-bound cotton/mL) of lysozyme. Enhancement of activity over soluble lysozyme may result from the solid-phase protection afforded by the cellulose linkage of the glycoprotein against proteolytic lysis. Computational models of lysozyme based on its crystal structure attached through aspartate, glutamate, and COOH-terminal residues to cellopentaose-(3) Gly-O-6-glycyl-glycine ester were constructed. The models demonstrate no steric constraints to the active-site cleft from the glycine-conjugated cellulose chain when lysozyme is bound at the carboxylates of Asp-87, Glu-7, Asp-119, Asp-18, and COOH-terminal Leu-129. The more robust antibacterial activity of the enzyme when bonded to cotton fibers suggests good potential for biologically active enzymes on cotton-based fabrics.

Anti-Bacterial Agents↗
PubMed2003

Entrained phase adsorption of PCDD/F from incinerator flue gases.

The emission abatement of polychlorinated dioxins and furans (PCDD/F) issued from municipal solid waste incineration (MSWI) is growing in importance because of more stringent emission standards and general health concern. These substances cannot be separated by conventional gas cleanup processes. They are successfully removed through adsorption onto carbonaceous materials, and the entrained-phase injection of pulverized adsorbents in the flue gas, followed by high-efficiency separation, is widely applied. Operating conditions and results obtained in Flemish MSWIs are given. The results illustrate the excellent overall removal efficiency: the regulation limit of 0.1 ng TEO/Nm3 dry gas at 11% O2 can be achieved. Furans are adsorbed to a slightly higher extent than the dioxins. The PCDD/F removal by carbonaceous adsorbents is thereafter modeled from first principles for the contribution of both entrained-phase (eta1) and cake filtration (eta2) to the overall efficiency (etaT), with dominant parameters being the operating temperature, the dosage and activity of adsorbent, and the fraction of adsorbent in the filter cake. Application of the model equations and comparison of measured and predicted overall efficiencies for the Flemish MSWIs demonstrate the validity of the model, which enables the MSWI operators both to predict the adsorption efficiencies for combinations of major operating parameters and to assess the sensitivity of the process to varying operating conditions. Finally, some practical difficulties encountered with the entrained-phase adsorption are discussed.

Adsorption↗
PubMed2003

Formation and extraction of persistent fumigant residues in soils.

Fumigants are commonly thought to be short-lived in soil, but residues have been found in soils years following application. In this study, formation and extraction of persistent soil fumigant residues were investigated. Fumigants 1,3-dichloropropene (1,3-D), chloropicrin (CP), and methyl isothiocyanate (MITC) were spiked into Arlington, Glenelg, and Hagerstown soils and incubated for 30 d under controlled conditions. The incubated soils were evaporated for 20 h prior to extraction with a variety of organic solvents at different temperatures. Extraction with acetonitrile in sealed vials at 80 degrees C for 24 h was the most efficient method to recover persistent soil fumigant residues. At application rates of 1000-1700 mg (kg of soil)(-1), persistent residues of 1,3-D, CP, and MITC in the three soils ranged from 5 to 67 mg kg(-1). The residue content increased with application rate, correlated positively with soil silt content, decreased dramatically as indigenous organic matter (OM) was removed, and changed little with external OM addition. Adsorption to clay surfaces was not important in fumigant retention, while pulverization of soil aggregates significantly decreased persistent fumigant residues. The results suggest that persistent fumigant residues are retained in soil intra-aggregate micropores resulting from binding clay flocs and silt particles by humic substances.

Adsorption↗
PubMed2003

Relative solubility of cations in Class F fly ash.

Coal utilization byproducts (CUB), such as fly ash, contain cations that may be released during exposure to fluids such as acid rain or acid mine drainage. Researchers at the Department of Energy's National Energy Technology Laboratory (DOE/NETL) have conducted a long-term column leaching study of 32 Class F fly ash samples from pulverized coal (PC) combustion, and quantified the release of 19 cations in four leachants with a pH between 1.2 and 12. The relative solubility (M(L/T)) of each cation was defined as the total mass leached (M(L)) relative to the concentration (M(T)) of that element in the fly ash sample. A frequency distribution of relative solubility values was computed with ranges defined as insoluble, slightly soluble, moderately soluble, and very soluble. On the basis of this sample set, Ba, Cd, Fe, Pb, Sb, and Se in PC fly ash are insoluble. The elements Al, Be, Ca, Co, Cr, Cu, K, Mg, Mn, Na, Ni, and Zn are slightly to moderately acid soluble. Only Ca and Na are water soluble; As and Ca are soluble in the basic solution, The results of this study indicate that the extent to which cations in Class F PC fly ash can be leached by naturally occurring fluids is very limited.

Coal↗
PubMed2004

Limestone-particle-stabilized macroemulsion of liquid and supercritical carbon dioxide in water for ocean sequestration.

When liquid or supercritical CO2 is mixed with an aqueous slurry of finely pulverized (1-20 microm) limestone (CaCO3) in a high-pressure reactor, a macroemulsion is formed consisting of droplets of CO2 coated with a sheath of CaCO3 particles dispersed in water. The coated droplets are called globules. Depending on the globule diameter and the CaCO3 sheath thickness, the globules sink to the bottom of the water column, are neutrally buoyant, or float on top of the water. The CaCO3 particles are lodged at the CO2/ H2O interface, preventing the coalescence of the CO2 droplets, and thus stabilizing the CO2-in-water emulsion. We describe the expected behavior of a CO2/H2O/CaCO3 emulsion plume released in the deep ocean for sequestration of CO2 in the ocean to ameliorate global warming. Depending on the amount of CO2 injected, the dense plume will descend a few hundred meters while entraining ambient seawater until it acquires neutral buoyancy in the stratified ocean. After equilibration, the globules will rain out from the plume toward the ocean bottom. This mode of CO2 release will prevent acidification of the seawater around the release point, which is a major environmental drawback of ocean sequestration of liquid, unemulsified CO2.

Calcium Carbonate↗
PubMed2005

Are renewables portfolio standards cost-effective emission abatement policy?

Renewables portfolio standards (RPS) could be an important policy instrument for 3P and 4P control. We examine the costs of renewable power, accounting for the federal production tax credit, the market value of a renewable credit, and the value of producing electricity without emissions of SO2, NOx, mercury, and CO2. We focus on Texas, which has a large RPS and is the largest U.S. electricity producer and one of the largest emitters of pollutants and CO2. We estimate the private and social costs of wind generation in an RPS compared with the current cost of fossil generation, accounting for the pollution and CO2 emissions. We find that society paid about 5.7 cent/kWh more for wind power, counting the additional generation, transmission, intermittency, and other costs. The higher cost includes credits amounting to 1.1 cent/kWh in reduced SO2, NOx, and Hg emissions. These pollution reductions and lower CO2 emissions could be attained at about the same cost using pulverized coal (PC) or natural gas combined cycle (NGCC) plants with carbon capture and sequestration (CCS); the reductions could be obtained more cheaply with an integrated coal gasification combined cycle (IGCC) plant with CCS.

Air Pollution↗