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Sugar cane is a culture of great importance worldwide due to the fact it is the raw material needed for the production of sugar, ethanol, and biomass, among other products. The micro-propagation of seedlings in a lab generates superior production when compared to the conventional process of propagation in the field. Therefore, it is seen as an alternative to produce healthy seedlings that present the same genetic load of the matrices. A disadvantage of micro-propagation is the high cost of workforce used in the process. The System of Temporary Immersion (SIT) was createdwith the goal of solving this issue. At the bio-factory Governador Miguel Arraes of the Center of Strategic Technology of the Northeast (CETENE), this system consists of 2 PET bottles of 5L (Bioreactors – BITs), a group of hoses and two Millipore filters of 0.22µm as well as automated controllers. Within the BITs it is possible to multiply a higher quantity of plants decreasing, this way, the time within the lab. Theobjective of this study is the qualitative analysis of the behavior of the System of Temporary Immersion using seedlings of different varieties of sugar cane. The methodology consisted of transferring the content of 1 or 3 pots, depending on the test, to the bioreactor with 200ml and 500ml of culture mean respectively. The varieties used were RB 86 3129 and B 8008 because there are fewer studies about them and of great interest to the Bio-factory. The variety RB 86 3129, on the first pricking, presented a better response than the B 8008, and days later the majority presented loss through contamination.

The purpose of this study was to find proper dentin substitute for standardized dentin barrier test and perform the cytotoxicity test of commercial bonding agents with the proper substitute.The three-dimensional cells attached to dentin disc or millipore filters as the dentin substitute were tested in a dentin barrier test by perfusion. MTT assay was performed as an evaluation method for the cell survival rate. The cytotoxicity test of serial phenol dilution by bovine dentin disc was done to determine a standard toxic material, and the test of this proper phenol by using various millipore combinations was performed to find the suitable dentin substitute. Also, the cytotoxicity test of bonding agents was performed by this standardized substitute. The cell viability was expressed as percentages of untreated group.Phenol concentration of 0.05 % was selected as the standard toxic material. The different combinations of millipore filters--two sheets of 0.45 μm, two sheets of 0.22 μm, and the combination of 0.65, 0.45, and 0.22 μm--showed similar cytotoxicity to natural dentin discs by 0.05 % phenol (p 0.05). The millipore combination of 0.65, 0.45, and 0.22 μm that had structural similarity to natural dentin discs was used as the substitute for cytotoxicity test of bonding agents. The toxic level of Adper Prompt L-Pop using the selected substitute was significantly the highest among four kinds of dentin bonding agents (p 0.05). Also, the dentin barrier test by the substitute showed constant results compared with the one by the natural dentin disc.The millipore filter combination of 0.65, 0.45, and 0.22 μm could be used as the substitute for the cytotoxicity test of materials applied to dentin.Dentin barrier test by standardized substitutes would be helpful for considering the potential toxicity of dentin bonding agents prior to clinical adaptations and reducing the variations of natural bovine dentin that has individually different characteristics.

Monocyte migration in millipore filters was measured by the leading front method. The precision, sensitivity and specificity of the method was assessed. The migrational response of monocytes to N-for-mylmethionylleucyl-phenylalanine (FMLP) was equal in concentrations ranging from 5times10−9 to 5times10−7 M. No dose-response relationship was demonstrated. The random analytical variation of the method was considerable, the mean coefficient of variation of duplicate experiments being 9.05%. The inter-subject variation was also large. A sample size of 30 to 40 individuals would be necessary to demonstrate a 1 SD difference between individuals at a significance level of 0.05 and power of 0.80. It is concluded that the method is able to detect agents which stimulate monocytes at least equally well as FMLP, but may be impracticable for demonstrating changes in monocyte migration, or differences in the migratory response among different populations of monocytes.

The distribution of leukocytes in Boyden millipore filters after stimulation with casein was determined after 30 and 180 min by the use of a photographic method. After 30 min the distribution was characterized by a second degree curve with a falling slope and after 180 min by a linear curve with a rising slope. The results showed that with most of the modifications of the Boyden method in use at present, the choice of incubation time is crucial for the evaluation of counting results.

In a double-filter modification of Boyden's method, formylmethionylleucylphenylalanine (FMLP) needed the presence of fresh plasma to induce leukocyte locomotor kinetics which compared with a model for directional migration. FMLP, or zymosan-activated plasma, did not stimulate migration in capillary tubes. The kinetics of leukocyte migration under agarose towards zymosan-activated plasma were more compatible to a model for increased random motility than for directional migration. Treatment of leukocytes with colchicin reduced their migration under gradient and non-gradient conditions in millipore filters, capillary tubes, and in under-agarose experiments.

The chapter describes procedures useful for determination of Ca(2+) binding by membranous Ca(2+)-ATPase based on the correction for the removal of Ca(2+) present in a non-bound state in the suspension medium. This is done by a filtration procedure that retains the membranous material on the Millipore filters. With suitable sucking devices it is possible to gently remove without dehydration nearly all medium from the Ca(2+) containing membranes, except that required for wetting of the filters on which they are deposited. Correction for this effect can be done with a double-filter where the radioactive content of the lower (protein-free) filter is subtracted from that present in the upper filter for calculation of Ca(2+) binding. This methodology can be used to study the effect of inhibitors on Ca(2+) binding and -transport, and with Ca(2+)/EGTA buffers to explore the Ca(2+) binding affinities and cooperative aspects of the two transport sites.

The main goal of thyroid fine-needle aspiration (FNA) is to distinguish nodules that require surgery from those that do not, thereby decreasing the number of diagnostic thyroidectomies. Several cytologic preparations are used to reach a definitive diagnosis, including smears using conventional stains, such as Diff-Quik (DQ) and Papanicolaou (Pap), millipore filters (MF), and cell blocks (CB). This study is undertaken to study the efficacy and adequacy to reach a definitive diagnosis of two cytologic preparations, MF and CB, in thyroid aspirates. All thyroid needle aspirates performed at Emory University Hospitals from January 2003 to April 2005 that had both MF and CB preparations for microscopic evaluation were studied. Conventional stains (DQ and Pap) were prepared. An initial aliquot of the specimen was divided for MF, and the remaining specimen submitted for CB preparation. All MF and CB slides were reviewed blindly. Adequacy criteria were assessed as 6–8 groups of follicular cells, with each containing 10 or more cells. Patient demographics, cytologic diagnoses, and follow-up information were retrieved. A total of 218 cases met our criteria; 21 of these cases were excluded due to lack of available diagnostic slides. Thus, a total of 197 cases were studied. Approximately two-third of the cases (57.9%) were diagnosed on DQ- and Pap-stained smears only, in which both CB and MF were inadequate. About 4.6% of the cases were diagnostic on both CB and MF; 36.0% on MF only, and 1.5% on CB preparation only. In more than half the cases (57.9%), diagnosis of thyroid FNA was rendered only on conventional stained smears. MF smears appeared to be superior for diagnostic yield (40.6%) than CB (6.1%), which is dependent on specimen cellularity. Therefore, MF rather than CB should be added to conventional stained smears (DQ and Pap) to supplement the diagnostic yield, especially in specimens of low cellularity. Diagn. Cytopathol. 2007;35:34–38. © 2006 Wiley-Liss, Inc.

An extensive investigation was carried out for the characterisation of the air particulate composition in Florence. The aim was to determine the aerosol elemental concentrations, as well as to identify pollution sources. For our investigation, the external Particle-Induced X-Ray Emission-Particle-Induced gamma-Ray Emission beam facility of the Istituto Nazionale di Fisica Nucleare, Van de Graaff accelerator at the Physics Department of the Florence University was used. We report the results of the analysis of a long temporal series (approximately 1 yr) of PM10 particulate samples, collected on Millipore filters on a daily basis in three different sites (characterised by different urban settings). Daily concentrations of more than 20 elements were detected. The long sampling period (approximately 1 yr) allowed a comparison with the air quality recommended values and the identification of seasonal variations. Four main sources (traffic, oil-combustion, soil-dust, and wind transported sea-salt) were extracted with the help of Principal Component Analysis (PCA). An absolute PCA showed traffic to be the major source both in the high traffic site and in the urban background site.

Summary Background Quantification of natural rubber latex (NRL) allergens of NRL glove extracts has been reported in several studies. Similarly, immunoassay studies reporting the level of NRL aeroallergens in air samples have been published. When studying the NRL allergens of gloves, however, little attention has been focused on identifying the relationship between extractable NRL allergens of medical gloves and NRL aeroallergens in indoor air. Objective In an experimental study we analysed NRL aeroallergens of medical gloves in joint relation to total airborne dust concentration and NRL allergen concentration in gloves. Methods NRL aeroallergen level was measured using a chamber setting with 18 lots of powdered medical gloves. In each setting 10 pairs of powdered NRL gloves were swinging in an unventilated chamber (9 m3). Air samples were collected using airflow through Millipore filters (pore size 0.8 µm). The filters were weighed before and after the experiment, and total airborne dust concentration in the chamber was calculated. The filter samples were then extracted and the NRL allergen level measured by IgE ELISA-inhibition assay. Furthermore, cut NRL gloves were extracted and analysed by the same method. Finally, levels of two major NRL allergens, Hev b1 and Hev b 6.02, were measured in three selected NRL glove brands. Results The NRL aeroallergen level in the chamber air ranged from

—Atmospheric aerosols were sampled from aircraft at various levels over Rihand in northern India during the monsoon season of 1974 and at surface levels at Calcutta, Delhi, Varanasi and Jodhpur during different seasons of 1970 and 1971. Millipore filter assembly was used for this purpose. Chloride nuclei, total aerosol and ice nuclei concentrations were evaluated from millipore filters. At Rihand/Varanasi, during the monsoon, the chloride size spectrum was broader and the distribution bimodal at cloud base level while the spectra were narrower and the distributions unimodal at other levels. At Rihand, chloride mass and larger giant chloride number were considerably higher, total aerosol higher while ice nuclei concentrations were lower on the days with moderate rain as compared to those with light rain. Calcutta (maritime) showed maximum while Varanasi (well-inland) showed minimum chloride number concentrations. As compared with Calcutta, Delhi (continental) had lower chloride and total aerosol, and markedly higher ice nuclei concentrations. Varanasi (high rainfall region) showed all the values, except for small-sized chlorides, notably higher with respect to Jodhpur (low rainfall region). Ice nuclei concentration was lowest in winter and highest in summer at Delhi. Variations of the aerosols during different parts of the day/night are also discussed.

An extensive investigation is in progress aiming at the characterisation of the air particulate composition in Florence. For our investigation, we use the external PIXE-PIGE beam facility of the I.N.F.N. Van de Graaff accelerator at the Physics Department of the Florence University. In order to gather information on both the longer- and shorter-time trends of the aerosol elemental composition, we are analysing both long temporal series (about 1 year) of 24-h Millipore filters collected by the health authorities in 3 different sites, and filters collected simultaneously in two of the above sites for about one month, by two streakers with one-hour resolution, providing size fractionation between particle size smaller than 2.5 μm and from 2.5 μm to 10 μm. The streakers sampling period includes two days during which the Municipality of Florence has banned the circulation of non-catalytic cars, due to the increase of NO2 above the “recommended safety values”. We present here the first obtained results for the sampling site located near a heavy traffic road.

Chondrocytes do not undergo terminal differentiation in normal articular cartilage, whereas growth plate chondrocytes synthesize ALPase and induce matrix calcification terminally. Articular chondrocytes in osteoarthritic joints have been reported to express the terminal differentiation phenotypes, suggesting that terminal differentiation of articular chondrocytes is inhibited in normal joints. In the present study, we investigated the underlying inhibitory mechanism of the terminal differentiation in articular cartilage using a culture on type II collagen-coated dishes or a novel culture model on Millipore filters. ALPase activity increased from day 7 to day 8 in growth plate chondrocyte cultures on the collagen-coated dishes, but not in articular chondrocyte cultures. The ALPase expression of growth plate chondrocytes on the collagen-coated dish was completely inhibited when the same number of articular chondrocytes was mixed in the growth plate chondrocyte cultures. When articular chondrocytes or growth plate chondrocytes were maintained on Millipore filters held in 16-mm dishes, they started to synthesize ALPase. The ALPase expression of the chondrocytes on Millipore filters was inhibited by the presence of articular chondrocytes maintained on the bottom collagen-coated substratum in the same dishes. These results indicate that factors that diffused into the medium through the Millipore filters are involved in the inhibition of terminal differentiation. Since the conditioned medium from articular chondrocyte cultures did not affect the ALPase expression, it is considered that the soluble factors, which are continuously released from articular chondrocytes, are responsible for the inhibition of terminal differentiation.

The present paper describes a quenching-and-washing chamber (QWC) to be used with a rapid-mixing apparatus (RMA) for the study of processes in the millisecond time scale. The QWC enables fast, nondestructive quenching by cooling and dilution of reactants in particulate systems that can be trapped on a filter. The reaction mixture (e.g., at 25 degrees C) is injected from the RMA into the QWC where it is immediately mixed with a stream of ice-cold solution flowing at a rate of 15-40 ml s-1. Quenching requires that the process studied is slowed considerably by cooling to 0-2 degrees C and/or by removal of reactants by dilution. The equipment was characterized through a study of the tight binding (occlusion) of 86Rb+ to purified, membrane-bound Na+/K+-ATPase. Millipore filters of 0.22-0.80 microm pore size trapped close to 100% of the enzyme protein. Enzyme with occluded 86Rb+ was formed in the RMA under conditions where the rate constant for release of Rb+ at 25 degrees C is up to 25 s-1 and then injected into the QWC. The high off-rate constant is due to the presence of 2.5 mM ATP, which accelerates release of Rb+. The recovery of occluded 86Rb+ on the filter was at least 90%, indicating that both cooling of the reactants and dilution of ATP are fast enough to stop the reaction. The quenching time was 3-4 ms.

The 4′-n-pentyl-4-cyanobiphenyl (5CB) liquid crystal is confined to the random interconnected voids of fibrous Millipore filter paper. The nematic to isotropic (NI) transition is studied using an ac calorimetry technique on Millipore filters of various void sizes. Even though the nematic correlation length is much smaller than all of the Millipore void sizes employed, substantial differences from the bulk behavior occur at the NI transition.

Survival of five strains of Vibrio cholerae, including serotypes O139 Synonym Bengal, O1 El Tor, and non-O1 were compared in water from a river. These bacteria were mixed with water from a river and the water filtered through 0.45 micron millipore filters, respectively, to yield a concentration of 10(6) CFU/ml and incubated at 5 degrees C and 20 degrees C for 21 days. The survival curve of V. cholerae O139 was almost the same with V. cholerae O1 and non-O1. The number of these bacilli decreased to less than 10(2) CFU/ml at 7 days of the incubation at 20 degrees C. When incubated at 5 degrees, however, these bacilli survived much longer and the number decreased to the same value after 14 days. Therefore, these results indicated that the temperature during the incubation greatly affects the survival of V. cholerae. On the other hand, when the water was filtered and used for the experiment, V. cholerae survived longer than in the polluted water. From these observations, if the river is polluted with V. cholerae O139 in the future, it is suggested that the distribution of V. cholerae O139 in the river may be the same as the present condition with V. cholerae O1 and non-O1.

A bacterial mixed culture was immobilized in Millipore filters to construct microbial-membranes for BOD determination using an oxygen electrode. The biosensor response was best when 0.5 mg cells were immobilized per cm2 of membrane, at 30°C, pH 7 and 0.05 M phosphate buffer. Reproducible microbial-membranes can be constructed and they can be stored for up to 20 days without appreciable loss of their response characteristics.

An automated turbidimetric method is presented for the determination of sulfate in lake water. Turbidity of samples filtered with 0.45 μm HA Millipore filters is measured at 420 mμm with a Technicon AutoAnalyzer after sulfate is reacted with BaCl 2 in HCl reagent. A NH 4 OH-EDTA rinse prevents coating of the BaSO 4 precipitate on the flowcell walls, glass coils, and plastic tubing of the manifold system, eliminating excessive baseline drift. There are no interference effects of seven ions most likely to occur in lake water. Recovery in tests and replicate analyses shows an accuracy better than ′2 percent and a precision of ′2 percent. The method is used to determine 5 to 40 ppm sulfate. Results are compared with those obtained from other automated turbidimetric methods.

Samplings were undertaken on the basis of a grid of 40 oceanographic stations distributed along eight sections with the same point of origin: in the middle portion of the mouth of Santos Bay (Fig. 1). Surface water samples were collected using a Niskin bottle. The water samples were filtered through AP-40 Millipore filters for chlorophyll

Radioactive bandages incorporating 32P, a high-energy beta- emitter, were prepared with an aim to have a radiation source that can be used for the treatment of superficial tumors. 32P-Chromic phosphate particles were prepared and filtered through Millipore filters. Filter incorporating 32P activity was immobilized between nitrocellulose membranes and placed on an adhesive bandage. There was no leakage of radioactivity from the bandage when tested in saline. Efficacy of the radioactive bandage for treatment of superficial tumors was tested in melanoma-bearing C57BL/6 mice. A single dose of treatment with 74 MBq 32P bandage resulted in tumor growth delay, whereas multiple dose treatment with 74 MBq 32P bandage at twice-weekly intervals resulted in complete tumor regression when treatment was started, when the tumor was merely palpable. Histology sections from the treated animals showed absence of tumor.

The Epiphany Resin-Percha Obturating System was assessed for cytotoxicity, compared with gutta-percha and AH-Plus sealer. Specimen disks (Resilon, gutta-percha), filled glass rings (sealers), or imbibed cellulose disks (primer, thinning resin) were placed over Millipore filters in direct or indirect contact with HeLa cell monolayer, incubated for 2 hours, and stained with tetrazolium blue. Cytotoxicity was rated by the surrounding unstained zone: none (0 mm), mild (≤7 mm), moderate (7–12 mm), or marked (>12 mm). Data were analyzed with one-way ANOVA and post hoc pairwise t tests. Unstained zones indicating moderate cytotoxicity were significantly larger (p < 0.05) for Epiphany primer than for thinning resin and for freshly mixed AH-Plus than for Epiphany sealer. Set sealers (24 and 48 hours), gutta-percha, and Resilon elicited noncytotoxic responses. In conclusion, cytotoxicity of set Epiphany sealer and Resilon was comparable with that of set AH-Plus and gutta-percha. Cytotoxicity of freshly mixed Epiphany sealer, primer, and thinning resin did not exceed that of freshly mixed AH-Plus.

The paper reports the results of a study of charge separation by forcing low conductivity liquids through micro-pore filters of different types and pore sizes. The influence of flItration on charging tendency of the test liquids has been studied for a range of flow rates and temperatures. The cellulose acetate cellulose nitrate Millipore filters charged the oils positively, while glass fibre Sartorius pre filters the oils negatively. The charging tendency of Norpar 15 d when the flow rate was > 6 x 10/sup -6/ m/sup 3//s). Based on the experimental results it is proposed that the charge content of the oil can be reduced by forcing the oil through defined micro-pore structure of known composition and by allowing the charged oil to relax electric relaxation chamber.

The effect of native venom of red (spitting) cobra (Naja pallida) on human erythrocytes is studied using the methods of electron microscopy and filtration through Millipore filters. Morphological analysis reveals marked transformation of discoid erythrocytes to echinocytes. More prolonged contact of the blood with the venom impairs the deformability of erythrocytes and induces hemolysis and the sludge syndrome. The results indicate a potent cytotoxic effect of native venom of red cobra.

Aims: This paper compares the faecal streptococci count on 25 samples of polluted waters obtained with three techniques: most probable number (MPN), membrane filtration (MF) and pour plate (PP) methods. Although the PP method is a simple technique, familiar to water bacteriologists, it is not recommended in the international methods. Methods and Results: For the MPN method, azide dextrose broth and ethyl violet azide broth were employed. For the MF technique, Millipore filters were placed onto azide maltose agar (KF agar), while for the PP method, 1 ml of a decimal water dilution was added to (Kennel Faecal) KF medium. Regression analysis and Friedman’s ANOVA were performed to determine the relationship between faecal streptococci counts obtained with the three techniques. Statistical analysis of the results showed that the MPN, MF and PP techniques were equally valid with respect to faecal streptococci enumeration in polluted waters. Conclusions: Since the PP method was found to be as good as the other techniques, it may be preferred in polluted waters. It is more economical in terms of both time and materials than the MPN count, and it is as accurate as the MF count. Significance and Impact of the Study: This study indicates that the PP method, although not recommended internationally, is a reliable alternative to MF and MPN.

A preliminary study of the atmospheric pollution in the centre of Algiers is one of the important fields of applications in the environmental science. Nowadays, we need to evaluate the level of the contamination which has an unfavourable effect on physicochemical properties of soils and plants and namely also on human health. In the present work, water samples collected from Oued El-Harrach Algiers River, have been filtered in 0.45 μm Millipore filters to be analysed by Energy Dispersive X-Ray Fluorescence technique using 109Cd radioisotope source. Concentrations of the toxic elements like heavy metals are determined and compared with the published ones values by Yoshida [1] and those obtained using PIXE and NAA techniques [6].

The smectic-$A$ to nematic (Sm-$A\ensuremath{-}N$) transition was studied confined to the randomly interconnected voids of Millipore filters via a high resolution calorimetry. The heat capacity peaks evolve from sharp and prominent to broad and small depending on void size. The random confinement drives the heat capacity critical exponent from the bulk value towards zero, indicating a confinement-induced decoupling of smectic and nematic order parameters.

A method for determination of the concentration of mercury in the gaseous phase is described. In the first step of the method a stable sulphur-mercury complex is formed. For this purpose sulphur is deposited on a filter and the investigated gas flows through the filter. Millipore filters and the deposition of sulphur from Na2S2O3 * 5H2O solution were found to be most suitable. The amount of Hg absorbed on the filter was determined by PIXE or by NAA in the second step of the method. An optimization of proton energy was performed in the PIXE analysis to obtain the maximal signal-to-background ratio. The detection limit of the method, expressed as the minimal amount of Hg which has to flow through the filter equals to 30 and 2 ng for PIXE and NAA techniques, respectively. Applications of the method are also described.

The response of ectomessnchymal cells of dog dental pulp to implantation of Millipore filters supplemented with bovine plasma fibronectin was evaluated after observation periods of one or four weeks. Two concentrations of plasma fibronectin were used (0.2 and 1 mg/mL). Experiments also included implants treated with control solutions (PBS or 1 mg/mL of dog albumin). Formation of a layer of elongated, polarized cells was demonstrated in direct contact with the implants treated with 1 mg/mL of plasma fibronectin solution, after one week post-operatively. Microfilamentous organization and orientation of rough endoplasmic reticulum was observed mainly in the supranuclear zone of the polarized cells. Implants treated with the same solution were consistently surrounded by a thick layer of dentinal matrix after four weeks of their exposure to pulp sites. Implants treated with control solutions or with the low concentration of fibronectin never showed any sign of cell polarization and matrix synthesis. These data provide evidence that the pulp cells can express their odontoblastic phenotype in response to a surface containing concentrated fibronectin (even allogenic), without the need of other molecules as exogenous inductive factors.

A new method is described to produce epithelial sheets by direct explantation of human sweat glands onto matrigel-coated millipore filters. The method is applicable to whole glands, separated coils or ducts and to normal and CF tissues. Electrogenic transport studies show that epithelia develop sodium transporting capability, even when explants are derived from secretory coils.

Previous studies have demonstrated that collagen substrates stimulate in vitro somite chondrogenesis, and that agents that elevate intracellular cyclic AMP levels in hibit the ability of somites to respond to the inductive influence of collagen. In the present investigation, radiommunoassay was utilized to compare the cyclic AMP content of somite explants cultured on purified Type I collagen substrates with control explants cultured on Millipore filters. During the period of culture, the cyclic AMP content of collagen-treated explants is significantly lower than the cyclic AMP content of control explants. The cyclic AMP content of collagen-treated explants is 66% of control values as early as one hour following the initiation of culture, and the cyclic AMP content of collagen-treated explants remains lower than controls throughout the 3-day cultured period. The greatest difference in the cyclic AMP content of collagen-treated and control explants is observed at the seventeenth hour of culture, at which time the cyclic AMP content of collagen-treated explants is 56% of controls. These results combined with previous studies provides support for the hypothesis that collagen elicits a reduction in the cyclic AMP content of embroyic somites and that this reduction is necessary to trigger chondrogenic differentiation.

Asbestos contamination of the outside aid in Paris and suburbs has been monitored in some environmental situations, namely, "typical" urban sites removed from known sources of asbestos emissions, crossroad locations, the vicinity of a freeway, areas with buildings under construction, and areas around asbestos factories. In the same manner, measurements have been performed inside buildings of various types: those sprayed with asbestos-containing materials, those fitted with asbestos products, and control buildings. Air has been sampled by use of 0.45 micrometer pore size Millipore filters. After low-temperature ashing, ultrasonicated ashes were transferred to carbon film on 200-mesh gold grids examined under an analytic transmission electron microscope. Levels of pollution were expressed in terms of gravimetric concentrations. Inside buildings, when the air was in contact with significant amounts of asbestos-containing materials (spray, sheets), the levels were in the range 0.1--1000 10(-9) g m-3. In the vicinities of asbestos plants, the concentrations were higher: 1000--3000 10(-9) g m-3. Under other circumstances, the levels were of the same order of magnitude: 99% of the values were below 7 X 10(-9) g m-3. The Conseil Supérieur d'Hygiène Publique de France proposed a numerical ambient air quality standard of 50 X 10(-9) g m-3 inside buildings sprayed with asbestos.

An application of cellulose nitrate as a nuclear track detector for determining the alpha activity from natural radionuclides 238 U, 232Th and their daughters in zircon sand was studied. The air suspended particulate having been deposited onto Millipore filters was examined. Using a new experimental procedure we were able to obtain accurate track detection. Depending on the working site, measured alpha activity ranged from 0.4 to 4.5. 10-2 Bq. m-3.

Periostea were dissected from 17-day-old chicken embryo calvariae, placed on millipore filters, and cultured on fluid media containing serum or on serum and plasma containing "plasma clots," in three ways: 1) with the osteogenic layer facing the filter, 2) with the osteogenic layer away from the filter, 3) folded such that the osteogenic layer was in apposition with itself within the fold. The cultures were studied histologically as well as biochemically. Periostea that were cultured folded showed differentiation of osteoblastlike cells after 2 days, and production of osteoid at day 4. Tissues cultured with the osteogenic layer away from the filter demonstrated similar osteoblastic differentiation and osteoid production. Both types of cultures exhibited an increase in histochemically detectable alkaline phosphatase activity over the 4 day culture period that was associated with osteoblasts and the osteogenic area. Periostea cultured with the osteogenic layer facing the filter produced no osteoid. In these cultures, histochemically detectable alkaline phosphatase activity decreased and virtually disappeared over the 4 day culture period. The possibility that the creation of a suitable micro-environment is required for osteodifferentiation in this culture system is discussed.

Implanted foreign bodies of certain shapes, especially large non-perforated polymer films, induce subcutaneous sarcomas in a high percentage of mice and rats; in contrast, implants of other shapes, e.g., perforated or minced films or Millipore filters with 0.45 microns pores, are non-carcinogenic or only weakly carcinogenic. Experiments described in this report have shown that when carcinogenic non-perforated film was removed at 3.5 months after implantation and one of the "non-carcinogenic" foreign bodies listed above was implanted into the same subcutaneous sites, a high percentage of sarcomas was induced. The same non-carcinogenic or weakly carcinogenic foreign bodies implanted in the mice after total body gamma irradiation or after single injection of ethylnitrosourea induced subcutaneous sarcomas in significantly higher percentages of animals than the same foreign bodies implanted in control mice. Our data suggest that foreign bodies of "non-carcinogenic" or "weakly carcinogenic" shapes can act as efficient promoters of subcutaneous carcinogenesis initiated by other agents such as implanted "carcinogenic" foreign bodies, ionizing radiation or chemical carcinogen.

Periodate-oxidized ppp(A2'p)3A was coupled in high yield to an acyl hydrazide derivative of bovine serum albumin and the conjugate was used to immunize rabbits. Several potent and specific antisera were obtained, and one was tested extensively. Fifty per cent of the bound probe ppp(A2'p)3A3'[32P]pCp was displaced by compounds containing the moiety -pA2'pA-at concentrations of 20-60 nM and by compounds containing the moiety -p(A2'p)2A- at 1 nM. The 3',5'-oligoadenylate (A3'p)3A was bound more than 10,000 times less tightly than (A2'p)3A. The antiserum can be used in competition assays in which the amount of an antibody-probe complex is measured after binding to Millipore filters or to polystyrene beads. These assays allow the clear detection of as little as 20 fmol (20 microliters of 1 nM) of 2',5'-oligoadenylates.

A direct counting method using millipore filters has been adapted to estimate numbers of soil ciliates present in both liquid media and soil samples. Comparisons were made between a two-fold dilution method and a first dilution method. It would appear that dilution techniques kill trophozoites, so that the counts from the direct millipore filter method were significantly higher. There was no significant difference between the method for cyst counts.

Whole human semen was centrifuged at various centrifugal forces to obtain sperm-free seminal plasma. Most samples of seminal plasma collected after centrifguation of up to 10,000 g were contaminated with spermatozoa. Centrifugation at 40,000 g yielded sperm-free seminal plasma in two thirds of the samples centrifuged. Filtration of whole semen with Millipore filters (pore size 0.45 mu) removed all spermatozoa.

The previous study in this series demonstrated that the ingrowth of the central axons of the trigeminal (V) ganglion is prerequisite to V motor axon outgrowth and somatic translocation. In the present experiment we determined whether further interactions with V ganglion cell bodies were required by V motoneurons after the V ganglion innervates the brainstem. Soon after the ganglion axons had penetrated the brainstem they were severed, and a barner, either permeable or impermeable, was placed between the ganglion cell bodies and the metencephalon. V motor axons grew along aberrant pathways to circumvent the impermeable barriers, many rerouting to reach the V ganglion. Only those V motor nerves which contacted the V ganglion distal to the barrier reached their target musculature in the mandible. The pattern of migration of V motoneurons was normal regardless of the V motor nerve trajectory, but the cell bodies of those axons which did not reach a muscle were not fully differentiated. When permeable barriers (Millipore filters) were implanted, the nerves followed two types of trajectories. If the pore size of the filter was small (0.45 and 0.025 μm), the V motor nerves grew identically to those observed in embryos in which impermeable barriers had been implanted. If the pore size of the filter was large (8.0 and 0.08 μm), the V motor nerve grew along its normal path directly to the barrier. Small axonal bundles from these nerves frequently grew into the filter toward the distal V ganglion. These results indicate that V motor axons preferentially grow to the V ganglion perikarya after exiting from the brainstem. Contact with the V ganglion always results in V motor nerve growth to the mandible while growth of the V motor axons to aberrant target sites only occurs when the axons fail to contact the V ganglion cells distal to the barrier.

Bias in chlorophyll measurements due to small photosynthetic organisms passing through 1.2 μm glass-fiber filters was investigated by comparing chlorophyll retained by these filters with that retained by 0.45 μm Millipore filters. At 24°N, the 1.2 μm glass-fiber filter passed an average of 8.9% of the total chlorophyll. At 47°N this bias averaged 4.4%.

Modifying the acridine orange staining procedure used for direct counting of aquatic bacteria, by staining the bacteria after filtering instead of in solution, gave bright fluorescence and eliminated the need for filtering stained samples. Millipore, Sartorius, and Nucleopore filters all gave good results with the staining method. Counts on the Nucleopore polycarbonate filters were about twice as high as on Millipore and Sartorius cellulose filters. Bacteria were counted and their heterotrophic activity measured as uptake and respiration of 14C‐glucose in 111 freshwater and marine samples. For standing waters which were not grossly polluted, bacterial counts per millilitre, using Millipore filters, varied between narrow limits (1.16–17.4 × 103), but the mean heterotrophic activity per bacterium showed a much wider range of values (0.6–111 × 10−11 μg.h−1).

The dynamic membranes were prepared of polyacrylic acid (PAA) and methylcellulose on Millipore filters. Al(III)-PAA dual dynamic membrane was also examined. RO performances of these membranes were clarified and the relationship between rejection and water flux was revealed by measurements of effects of membrane forming conditions on performances. From observation by SEM, the membranes were classified into 3 types ; the membrane inside filter, the membrane on filter, and the dual membrane. It became clear that the PAA layer was formed in Al(III) layer in the case of the dual membrane.

HeLa and L-M cells can be effectively grown directly on glass fiber filters to yield replicate cultures that allow easy analysis of biosynthetic capabilities through measurement of radioactive precursor uptake and incorporation. The glass fiber filters are superior to glass cover slips, growth in scintillation vials, and growth on Millipore filters in the ease of handling during experimental treatment and in the amount of radioactivity incorporated during the labeling period. These parameters are experimentally established and a typical application of the procedure that demonstrates the hydroxyurea inhibition of DNA synthesis is presented.

A simple method is described for obtaining a representative field of subcellular fractions for thin section electron microscopy. The prefixed sample is admixed together with high molecular weight dextran, filtered onto a Millipore filter, and embedded in polymer. Filtration serves to uniformly distribute structures of different sizes and densities. The dextran serves as a nonosmophilic spacer, increasing the space between individual structures and preventing sample compression during filtration onto Millipore filters. Sample aggregation can also readily be assessed by the procedure.

This communication demonstrates further that terbium(III) can be used as a probe for DNA. The stoichiometry of terbium binding to DNA was measured by two new methods. In the first method, calf-thymus DNA was titrated with radioactive terbium-160, which is an isotope of the common terbium-159. The resulting DNA-terbium complex was trapped and measured on millipore filters. In the second method, a peak of UV absorption of terbium was found at 219 nm and was used to measure stoichiometry. By both methods, the stoichiometry of binding was one Tb(III) for each three available phosphate groups in DNA. Finally, a rapid method was developed using terbium-160 to measure the amount of nucleic acid in a solution.

The influences of alpha particles' energy and angle of incidence on the readout obtained from cellulose nitrate plastic track detectors, exposed to materials emitting alpha particles, have been studied as a function of etching time. Simple detection equipment has been developed to allow precision measurement of superficial alpha activity. The technique has been applied to determine the air concentration of an alpha emitting suspended paniculate, after deposition onto Millipore filters.

The RNA associated with poly(A) sequences from Euglena gracilis and Vicia faba has been isolated by binding to millipore filters and characterized by sedimentation velocity centrifugation and electrophoretic mobility. Poly(A)-associated RNA as isolated in solution was highly aggregated. When denatured, it sedimented as a broad peak with a mean value of 16–18 S. This RNA was shown to be covalently linked to poly(A) sequences which are 150–250 nucleotides long. Our size estimates for plant poly(A) and poly(A)-associated RNA are similar to those obtained for animal cells.

We have measured the binding of 14C-ADP to isolated human platelet membranes by a technique using 0.8-μm Millipore filters to separate unbound tracer from membrane-bound nucleotide. The binding was dependent on the time of incubation and on the nucleotide concentration in the medium. The affinity constant was found to be comprised between 0.35 × 106 and 0.55 × 106 M-1. Platelet membranes prepared from different thrombasthenic patients bound 14C-ADP with the same kinetic parameters as those from normal subjects. The affinity constant as determined for two of these thrombasthenic platelet membrane preparations was in the normal range.