ABSTRACT
A new technique was developed to measure membrane fouling, which is derived from the capillary suction time (CST)--a parameter often used to indicate the dewaterability of sludge--and which is called the modified CST (CSTm). The results indicate a good repeatability and reproducibility of the test. Spiking tests with suspended solids and humic acid, which have a high fouling potential, resulted in a significant rise of the CSTm value, indicating a sensitive assessment of these fouling components. However, the CSTm measurement is mainly indicative for the colloidal fouling of the sample.
Subject(s)
Waste Disposal, Fluid , Capillary Action , Environmental Monitoring , Humic Substances/analysis , Membranes, Artificial , Suction/methods , Ultrafiltration/methods , Waste Disposal, Fluid/methodsABSTRACT
The alpha- and beta-D-lyxofuranosyl analogues of the naturally occurring nucleosides have been synthesized and their antiviral properties examined. The alpha anomers were prepared by glycosylation of purine and pyrimidine aglycons with tetra-O-acetyl-alpha-D-lyxofuranose, followed by removal of the blocking groups. The beta anomers were obtained by sequential oxidation and reduction of 3',5'-O-(1,1,3,3-tetraisopropyldisiloxane-1,3-diyl)-beta-D-x ylofuranosyl nucleosides. The lyxofuranosyl nucleosides were tested for their activity against a variety of RNA and DNA viruses and for inhibition of cell growth. One compound, 9-alpha-D-lyxofuranosyladenine, showed activity against herpes simplex virus types 1 and 2 both in vitro and in vivo.
Subject(s)
Antiviral Agents/chemical synthesis , Nucleosides/chemical synthesis , Animals , Antiviral Agents/pharmacology , Herpes Simplex/drug therapy , Mice , Nucleosides/pharmacologyABSTRACT
The alpha- and beta-D-xylofuranosyl analogues of the naturally occurring nucleosides, as well as other D-xylofuranosyl derivatives, have been the subject of a systematic synthesis and examination of their biological, i.e. antiviral antimetabolic, and cytostatic properties. The beta anomers were prepared by glycosylation of purine and pyrimidine aglycons with peracylated 1-O-acetyl-alpha-D-xylofuranoses, followed by removal of the blocking groups. The alpha anomers were obtained by a multistep synthesis with use of 2-amino- or 2-mercapto-alpha-D-xylofuran[1',2':4,5]-2-oxazoline as starting material. The xylofuranosyl nucleosides were tested for their activity against a variety of RNA and DNA viruses and for inhibition of cell growth and macromolecule synthesis. Three compounds, 9-(beta-D-xylofuranosyl)adenine, 9-(beta-D-xylofuranosyl)guanine, and 1-(beta-D-xylofuranosyl)cytosine, showed marked biological activity.
Subject(s)
Antiviral Agents/chemical synthesis , Nucleosides/chemical synthesis , Animals , Antiviral Agents/pharmacology , Antiviral Agents/toxicity , Cell Division/drug effects , Lethal Dose 50 , Mice , Nucleosides/pharmacology , Nucleosides/toxicity , RabbitsABSTRACT
Confusion exists about the chromium and cobalt concentrations in the serum of healthy individuals. We determined these elements by neutron activation analysis. The samples were irradiated during 12 days at a flux of approximately 10(14) neutrons.cm-2.s-1. Chromium was selectively separated by distillation after the irradiation. We obtained the following values (mean +/- standard deviation): 0.160 +/- 0.083 mug/liter for chromium, and 0.108 +/- 0.060 mug/liter for cobalt.
Subject(s)
Chromium/blood , Cobalt/blood , Blood/radiation effects , Chromium Radioisotopes/blood , Cobalt Radioisotopes/blood , Humans , Neutron Activation Analysis/instrumentation , Neutron Activation Analysis/methods , Reference Values , Spectrometry, GammaABSTRACT
We determined the iron, zinc, selenium, rubidium, and cesium concentrations in serum and packed blood cells by instrumental neutron activation analysis without chemical separations. Lyophilized samples were irradiated for 12 days at a flux of 10(13) neutrons-cm-2-s-1, mineralized by wet digestion, and measured two times with a high-resolution Ge(Li) detector--for 6 h about a month after the irradiation and for 15 h two or three months after the irradiation, The following values were obtained: 163 +/- 0.43 mg/liter (serum iron), 1025 +/- 136 mg/kg wet wt (packed cells iron), 1¿ +/- 0.20 mg/liter (serum zinc), 11.15 +/- 1.83 mg/kg wet wt (packed cells zinc), 0.13 +/- 0.02 mg/liter (serum selenium), 0.16 +/- 0.03 mg/kg wet wt (packed cells selenium), 0.17 +/- 0.04 mg/liter (serum rubidium), 4.28 +/- 0.98 mg/kg wet wt (packed cells rubidium), 0.74 +/- 0.20 microgram/liter (serum cesium), and 4.82 +/- 2.10 microgram/kg wet wt (packed cells cesium).
