Different Kinds Of Water Research Articles

Polyamide 4,6 membranes for the encapsulation of Langerhans islets: preparation, physico-chemical properties and biocompatibility studies.

Porous polyamide 4,6 membranes developed as semi-permeable and biocompatible membranes for the encapsulation of pancreatic islets were prepared by precipitation in water. Different membrane morphologies were obtained by varying the molecular weight of polyamide 4,6, the solvent evaporation time and the composition of the casting solution. Each membrane was submitted to differential scanning calorimetry and water flux measurements to study the total water content and the different kinds of water in correlation with its permeability performances. Their biocompatibility was first evaluated by a surface protein adsorption test. Of the various membranes, the one prepared by immersion in water after 5 minutes of solvent evaporation, of 15% KS200 polyamide 4,6 solution added with 1% of polyvinylpyrrolidone K30 seems to be the most promising. This membrane is characterized by a low adsorption of proteins, a high hydraulic coefficient and an asymmetric structure. Such a membrane represents a good candidate to be an efficient immunological barrier. It also exhibits good glucose and insulin diffusion properties. Moreover, rat islets cultivated on its surface were not affected by its presence and no important cell adhesion was noticed when implanted in mice. This membrane exhibits most of the properties suitable for the islet encapsulation with a view to developing a bioartificial pancreas.

Application of low-level counting techniques for the investigation of the impact of uranium mining as well as remediation on the environment

A chamber with a shield of steel and lead of a total surface density of 365 g cm −2 for low-level measurements has been installed within a cave at an old brewery named ‘Felsenkeller’ in the Weisseritz-valley near Dresden. In the 45 m deep underground laboratory 98% of cosmic muons are shielded by the rock. Low detection limits are necessary for the measurement of different kinds of water and biological samples. The use of γ-spectrometry reduces the need for complex chemical separation procedures.

Optical properties of water and spectral light absorption by living and non-living particles and by yellow substances in coral reef waters of French Polynesia

Spectral optical properties in different kinds of water were studied at several islands in French Polynesia. Optical differences between the waters of a high island (Moorea, Society archipelago), an atoll (Takapoto, Tuamotu archipelago) and the ocean above the outer reef slope were first assessed in terms of irradiance and diffuse attenuation coefficients. These differences were analysed with respect to the effect of phytoplankton, non-living particles and yellow substances, with these 2 latter components being responsible for most of the variations observed. Absorption coefficients for phytoplankton and non-living particles, as well as absorption by yellow substances, were also measured in the waters of the high island of Tahiti (Society archipelago) using the 'glass-fiber filter' technique and spectrophotometr~c measurements, respectively. These data showed large spatial variability of absorption, the main absorbing compound varying from one location to another depending on whether a station was mainly influenced by emergent land or by the ocean. Specific absorption coefficients for phytoplankton showed marked spatial and temporal vanations among the stations. Spatial variations were related to concentrations of chlorophyll a and covarying pigments, taxonomic differences and total suspended particles. Temporal variations were probably caused by differences in the incident UV radiation between summer and winter These results show that optical properties of water can be used to describe the medium in aquatic environmental studies.

Ultra-morphology of coliphages isolated from water

Using the ARCAT technique for coliphage detection, variations in different plaques have been noted. Investigation on the associated phage ultra-morphology for 45 plaques isolated in different kinds of water in Sao Paulo State, Brazil indicated the phages involved belonged to three families: Myoviridae, Podoviridae and Siphoviridae. There were no apparent relationship between coliphage family and specific plaque morphology. Escherichia coli strain ATCC 13.706 detected a broad spectrum of coliphage in water. A high diversity of coliphages were detected in the water analysed.

Comparison of different media for the identification and quantification ofAeromonas spp. in water

In order to assess the suitability of the Starch glutamate ampicillin penicillin-10C agar for the isolation of Aeromonas spp. from waters it was necessary to compare the properties of this medium with those of three others, Starch ampicillin agar, Ampicillin dextrin agar and m-Aeromonas medium, and to monitor different kinds of waters. A selection of forty eight samples were taken from moderately polluted river water, highly polluted river water, polluted sea water (littoral) and treatment & distribution water and monitored using these media. The results were similar with Ampicillin dextrin agar, m-Aeromonas medium and Starch glutamate ampicillin penicillin-10C, but the simplicity of composition and use and its selectivity recommends the last medium as the most adequate for the isolation of Aeromonas spp.

Yield and mineral composition of ‘Verna’ lemon trees as affected by salinity and rootstock combination

Effects of salinity on fruit yield during 1985-87 and leaf mineral composition during 1986/ 1987 were studied in a field experiment with lemon trees cv. Verna on either macrophylla (C. macrophylla Wester) rootstock or with a sanguina orange interstock on ‘Cleopatra’ mandarin (C. reticulata Blanco) and sour orange (C. aurantium L.) rootstocks. Trees were irrigated with four different kinds of water having Cl~ concentrations that ranged from 6 to 42 mol m-3. Fruit yield was progressively decreased by salinity in all treatments, but the effect was influenced by the specific rootstock combination. Chloride concentrations in leaves from the combinations where sanguina orange interstock was present were significantly lower than those from the Citrus macrophyllal'Verndi’ lemon combination. Data on the accumulation of other nutrients in relation to the specific rootstock combination, sampling date and saline treatment are also presented. The importance of each effect depended on the nutrient considered.

Membrane filter procedure for enumeration of Pseudomonas aeruginosa in water

In this report, the efficiency of replacing the antibiotics in mPA-C and mPA-D agars by C-390 as selective agent, has been studied, and compared with MPN procedure. In a second step a resuscitation technique to recover stressed Pseudomonas aeruginosa cells has been tested with the mentioned MF media. Counts obtained with MPN technique were always significantly higher than when using MF without resuscitation. No significant differences were obtained between MPN and MF technique when the resuscitation step was used with the second one. mPA-C390 and mPA-D390 present the advantage of being autoclavable and specific for selective isolation of P. aeruginosa from different kinds of waters.

A thermoanalytical approach to the study of the tissutal water of mouse salivary glands

The salivary glands participate to a different extent when secreting the different components of saliva. The cellular water plays a very important role in this process, but studies concerned with water analysis and characterization in these organ tissues have not been reported in the literature. The different kinds of water, their percentages and their stabilities were determined by thermal analysis of mouse salivary glands: submandibular, sublingual and parotid. The water was released from the different types of gland in different temperature ranges; the most stable being the submandibular gland, followed by the parotid gland, and then the sublingual gland. The total water per cent was approximately the same (about 72.5%) in the submandibular and sublingual glands even if bound with different energies to the matrix, but a remarkable difference was found between the water per cent corresponding to the first process of the submandibular and sublingual glands. The parotid glands showed a lower per cent (66.6%) for total water. Finally, the thermogravimetric curves were found using the same analysis, to obtain the ashes content of the glands.

Composition and dynamics of iron in iron-poor ferritin

Mossbauer spectroscopy has been used to study Fe(III)-apoferritin complexes, formed after the addition of Fe(II) to apoferritin in air. The spectra showed the presence of divalent, dimeric trivalent and small clusters of trivalent iron. The amount of divalent and dimeric iron and the average iron-iron distance in the small clusters, diminished with time. The dynamic behaviour of iron in iron poor ferritin crystals, indicating that the iron is bound differently in the two systems and showing the role of different kinds of water in ferritin on protein dynamics.

A practical isolation of methyl mercury in natural waters

A simple method to isolate both organic and inorganic mercury in natural waters is described. The mercuric compounds were quantitatively extracted with dithizone from six different kinds of water spiked at nanogram levels with radioactive mercuric chloride and methylomercuric chloride. After the separation from the inorganic mercury with sodium nitrite, methyl mercury was transferred to aqueous medium with sodium thiosulfate. The method provides a high recovery of organic as well as inorganic mercury to an aqueous medium, prior to their determination by gold-trap cold vapor atomic absorption spectrophotometry. This method is easy, rapid, and inexpensive. Furthermore, the limited number of analytical steps should reduce loss and contamination.

States of Water Sorbed on Wool as Studied by Differential Scanning Calorimetry

The states of water sorbed on Merino wool fibers, their histological components, and chemically modified wool fibers were investigated by differential scanning calo rimetry (DSC) in order to elucidate the amount of bound water on wool fibers, the differences between the histological components of wool fibers, and the effect of polar groups on the states of water sorbed on wool fibers. For the sake of comparison, the states of water sorbed on cotton and silk were also examined. There may exist three different kinds of water sorbed on wool fibers, i.e., free water, freezing bound water, and nonfreezing bound water. The amount of bound water on wool fibers is larger than that on cotton yam and silk. The amount of bound water on cortical cells is about two times higher than that on cuticular cells. The amount of bound water on nonkeratinous cell components is about three times higher than that on keratinous cell components. The cell membrane complex plays an important role in water pen etrating to wool fibers, but its contribution to the amount of bound water is negligible. The contribution of polar groups in wool fibers to the amount of bound water is not specific at high water contents, indicating that the peptide groups of the main chain play a significant role as water binding sites at high water contents.

A chelating agent - activated carbon - PIXE procedure for sub-ppb analysis of

By combining suitable water preconcentration techniques and Particle-Induced X-ray Emission analysis (PIXE), we have developed a procedure for multielemental sub-ppb water analysis. The preconcentration step consists of adsorbing the metals in the form of organic chelates onto activated carbon, which is pressed to a tablet and then analysed by PIXE. For very low concentrations and small volumes of water, a “mini-tablet” technique of sample preparation is employed. The versatility of the chelating-adsorption-PIXE procedure is demonstrated for several different kinds of water.

Multielement X-Ray fluorescence analysis of natural waters by using a preconcentration technique with ion exchange resins

The analysis of trace element in different kinds of waters is described, using a preconcentration technique on ion exchange loaded filter papers. The filters were analyzed employing an energy dispersive X-ray fluorescence system characterized by radioisotopic excitation sources and gas proportional or semiconductor detectors. The detection limits of the method were experimentally determined and the elemental levels in typical waters were measured.

The Dependence of the Oxygen Isotope Fractionation in the Hydration Water of CuSO4 · 5 H2O on the Crystallization Temperature

Abstract The fractionation of the oxygen isotopes in the water collected by stepwise dehydration of CuSO4·5H2O has been measured for the crystallization temperatures 25, 40 and 50 °C. From X-ray and neutron diffraction studies it is known that three different kinds of water, differing in their binding in the crystal, exist in CuSO4 · 5 H2O. On the basis of the results reported here it is concluded that isotopic equilibrium exists between the different kinds of water in the crystal and the mother liquor during the crystallization process. In addition it is shown that on stepwise dehydration the water molecules from the different types of sites can be separated. Consequently, the measurements provide the possibility to determine crystallization temperatures from intracrystalline oxygen isotope fractionation alone. Possible applications in isotope geothermometry are discussed.

XXVII. Account of the airs extracted from different kinds of water; with thoughts on the salubrity of air at different places. In a letter from the Abbé Fontanta, director of the cabinet of natural history belonging to his Royal Highness the grand duke of Tuscany, to Joseph Priestly, LL.D, F. R. S

I take the liberty of sending you an account of some experiments which I made Paris in the years 1777 and 1778 on the air extracted from various kinds of waters: some of the principal of which I though proper to transcribe, that you might make use of them if you think that they are at all useful, and likewise lay them before the Royal Society.