Measuring memory for source: some theoretical assumptions and technical limitations

In a search for pathogenetic mechanisms underlying retention hyperkeratosis, we examined the pH gradient over the stratum corneum in 13 male patients suffering from either x-linked recessive (XRI) or autosomal dominant ichthyosis vulgaris. For recording pH values, a flat glass electrode was repeatedly applied to the skin during tape stripping of mildly involved forearm skin. Before stripping, surface pH was higher in ichthyosis vulgaris (5.3 +/- 0.7; n = 7) than in XRI (4.6 +/- 0.4; n = 6; p < 0.05) and healthy control men (4.5 +/- 0.2; n = 7; p < 0.01). Removal of stratum corneum, which required 100-240 strippings in ichthyotic skin and 80-120 strippings in healthy control skin, disclosed markedly different pH variations in the two types of ichthyosis. The major abnormality in ichthyosis vulgaris skin was that a neutral pH was attained already halfway through the horny layer, possibly reflecting a congenital lack of acidic breakdown products from keratohyaline. By contrast, stripping of XRI skin revealed a shallow pH gradient that plateaued at 6.2-6.6, instead of about 7 as in normal and ichthyosis vulgaris skin. A likely explanation is the XRI-associated accumulation of cholesterol sulfate in lower stratum corneum. Our results suggest that the "acid mantle" of normal skin, which penetrates deep into the stratum corneum, is the combined result of cornification-associated organic acids and back-diffusion of acid material from the surface. Because corneocyte desquamation involves many pH-dependent enzymes, abnormalities in the transcorneal pH gradient might play a role in the pathogenesis of ichthyosis.     

Adsorption studies of recalcitrant compounds of molasses spentwash on activated carbons

Due to high levels of residual chemical oxygen demand (COD) in the effluent of molasses spentwash (MSW) after anaerobic treatment, acceptable COD levels for discharge cannot be achieved without some form of post-treatment. In this study, the particulate composition of molasses spentwash after anaerobic digestion (MSWD), is characterised as to its particle size distribution, using micro- and ultrafiltration and three activated carbons are characterised as to their ability to reduce significantly the COD of MSWD effluent. The activated carbons tested as adsorbent, were characterised by XPS spectroscopy, elemental analysis, surface area, pore size distribution, and acid-base titration using the Boehm's method. Adsorption of phenol, used here as a reference compound, and of some organic compounds contained in MSWD (gallic acid, tannic acid, and melanoidin, respectively), was studied. It was clearly demonstrated that an activated carbon with a significant distribution of both micropores and mesopores and a significant amount of macropores that are assumed to act as conduits providing access to micro- and mesopores, have a good adsorption efficiency for compounds such as tannic acid and melanoidins. It is a good adsorbent for melanoidin and coloured compounds of MSWD, which represents a large source of the aqueous pollution in sugar cane industries.     

Technical bases and acquisition conditions of electron-beam computed tomography

PURPOSE: In this review the technical principle and scanner characteristics of electron beam computer tomography (EBCT) are discussed. METHODS: In contrast to conventional CT, image acquisition in EBCT is achieved without mechanically moving parts. This construction allows for short acquisition times in investigating given anatomical regions (100 ms per slice) or up to 8 levels without table movement and short interscan delays (50 ms per slice). RESULTS: Depending on the nature of the investigation, the scanner can be used in the single slice, continuous volume scanning and multi slice mode. The single slice mode is used for detection and quantification of coronary calcifications and for CT angiography of the coronary vessels. Equivalent to the spiral mode in conventional CT, continuous volume scanning may be used for routine investigation of the chest and abdomen. Functional investigations of the heart and perfusion measurement of different organs can be performed in multi slice mode. Because of the geometry of the electron beam scanner, radiation exposure for certain investigations is above the exposure with conventional CT. CONCLUSION: Future developments will focus on dose efficient radiation collimation, high resolution detector systems and artefact reducing reconstruction kernels.     

La diffusion intraparticulaire dans la clinoptilolite application aux ions Na+ et NH4+Intracrystalline self-diffusion of ions in clinoptilolite ammonia and sodium cations studies

Studies on NH₄⁺ removal by mean of a zeolite: clinoptilolite, previously realised have led the authors to examine the exchange mechanisms between cations on the clinoptilolite grains.The use of clinoptilolite as conventional ion exchange resin (1, 2, 3, 4, 5, 6) for elimination of ammonia ion from waste waters or drinking water (7, 8, 12) poses a great number of difficulties, principally during regeneration.This text presents a brief theorical presentation of the material and the ion-exchange, especially in the case of isotopic exchange, allowing the introduction of the fundamental equation (2) and its approximate expression:

$\text{U(t)}\text{1?exp}\text{?}\text{D}\text{tπ}{}^2\text{r}{}^2{}_0{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$

with U(t) the exchanged fraction at time t.The experimental study concerns the NH₄⁺ cation exchange with Na⁺ ions on clinoptilolite.In this case, the curve u(t) and ln(l ? u²) vs time shows the non-applicability of the above formula (Fig. 5).Our subject was to examine the divergence causes and to propose for our regeneration problem a semi-empiric law which form is:

$\text{U(t)}\text{1?exp}\text{?}\text{β}\text{D}\text{tπ}{}^2\text{r}{}^2{}_0{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$

with

$\text{β=[1?U(t)]}\text{2}\text{3}$

.The validated relation (Fig. 7) for the Na⁺/NH₄⁺ exchanges lead us to find the D_Na⁺ and D_NH2⁺ coefficients consistent with the literature.Using the experimental results from AMES, we show that our formula can be applied to other exchange cases (e.g. Sr⁺/NH₄⁺) (Fig. 8). The form of the β relation seems coherent with the proposed film diffusion interpretation.     

Utilisation de la clinoptilolite en potabilisation des eaux—elimination de l'ion NH4

The objective of this study is to develop a technique to remove ammonium ion from water intended for potable purposes. An ion exchange method is used with a selective ion exchanger, a natural cation zeolite, clinoptilolite. Glass columns (Fig. 1) are used for laboratory experiments. These experiments show that the NH₄⁺ exchange capacity is very small compared to its total capacity 2.17 meq g⁻¹; its value depends essentially on the NH₄⁺ initial concentration and less on the Ca²⁺ concentration in the influent water. Figure 3 illustrates the practical exchange capacity relative to the initial concentration of ammonium ion for a soft water (Ca²⁺ = 35–50 mg l⁻¹). We were particularly interested in waters weak in ammonium ion concentration (NH₄⁺ = 1–3 mg l⁻¹). In this case and for 1 and 2 mg l⁻¹ NH₄⁺ concentration in water, the practical capacity is only 0.06 and 0.108 meq g⁻¹ respectively. The leakage is smaller than the ECC limit (European Community Council) for drinking waters (NH₄⁺ 0.5 mg l⁻¹) and the treated volume of water to breakthrough, defined at 0.5 mg l⁻¹ of NH₄⁺, is 720 BV (BV = bed volume) in both cases.In another way Fig. 6 shows that hard waters (due to Ca²⁺ ions) are more difficult to treat than soft waters. The practical capacity is smaller than before and the NH₄⁺-leakage is greater. To lessen NH₄⁺-leakage to less than 0.5 mg l⁻¹ for soft waters down-flow and up-flow, regeneration is used. Figure 7 shows that up-flow regeneration is more attractive than down-flow regeneration.Cycle reproducibility (Figs 4 and 5) shows that the regeneration conditions satisfied our requirements: in this case, the salt consumption is 180 eq of salt per eq of NH₄⁺ eliminated. This prompted us to try to reuse the regenerant (with NH₄⁺ ion). An increase of NH₄⁺-leakage is noticed in the presence of an NH₄⁺-residual in the regenerant. This increase is more significant with down-flow regeneration.After these laboratory experiments, we carried out a semi-industrial pilot-plant. Our objective was first to verify the laboratory results and secondly to study clinoptilolite behaviour relative to the time it was used. Two plexiglass columns comprise the pilot-plant shown in Fig. 9; soft water is used for these experiments. The first column is regenerated with fresh salt solution. The cycles obtained, considering their initial NH₄⁺-concentration, are reproduced in Fig. 10. For 2 mg l⁻¹ NH₄⁺ in the influent water, the leakage is about 0.2 mg l⁻¹ and the treated volume to breakthrough (0.5 mg l⁻¹ of NH₄⁺) is about 750 BV. The second column is regenerated with a recycled solution. The quality of the cycles decreases with the number of reuse of the regenerant as shown in Fig. 11. Nevertheless, it is interesting to note that after 3 reuses, the performance decrease is only 25% and the leakage, although it increases is smaller than 0.5 mg l⁻¹.Pilot results allowed us to propose a treatment of 30,000 m³ day⁻¹; the cost per cubic meter water treated, relative to NH₄⁺-removal, is about 0.165 FF (0.033 US $) for a plant and 0.77 FF (0.014 US $) for the same plant at the seaside. Using two serial columns decreased the cost by about 40–50%.     

Identification of a hypoperfused segment in bull's-eye myocardial perfusion images using a feed forward neural network

Artificial neural networks are computer systems which can be trained to recognize similarities in patterns and which learn by example; one of the more straightforward types being the feed forward neural network (FFNN). We previously reported the use of FFNNs for classification of hypoperfusion patterns in bull's-eye representation of 201Tl single photon emission tomography myocardial perfusion studies and showed that, when such an image was divided into 24 segments, FFNNs could detect perfusion defects without direct comparison to a normal data base. This has been extended in this investigation to assess the ability of an FFNN, trained on data in which only a single segment was hypoperfused, to detect this abnormal segment when the hypoperfusion pattern of the other segments in the image varied. The results indicated that the network could reliably determine whether a segment was normally or under perfused, with accuracies of 99% and 100%, respectively, if all other segments were normally perfused. It could also reliably detect a normally perfused segment, even if other segments were hypoperfused, with accuracies of 95% and 98%. The network was less reliable, however, in detecting a hypoperfused segment when other segments were also hypoperfused, showing accuracies of only 74% and 88%.     

The possible significance of parallel changes in plasma lutein and retinol in Pakistani infants during the summer season

We established new cell lines from head and neck cancer patients for studies of adhesion molecules and cellular behavior in nine patients with primary or metastatic cancer treated at the Asan Medical Center. Explant cultures of fresh tumor tissue were used to develop new permanent tumor cell lines. Lines were tested for tumor formation and histology in nude mice. Flow cytometry and indirect immunofluorescence were used to assess DNA content and expression of the alpha 6, beta 4, and beta 1 integrin subunits and the intercellular adhesion molecule 1 (ICAM-1). In vitro growth patterns and adhesion to plastic were assessed using phase contrast microscopy. AMC-HN-1 to -8 were derived from patients with squamous cell carcinoma. AMC-HN-9 was from an undifferentiated carcinoma of the parotid gland. The 8 lines we tested produced nude mouse tumors that are identical to the histology of the original tumors. AMC-HN-1, -2, -5, and -9 have epithelioid or spindle cell morphology with poor cell-to-cell and cell-to-substrate adhesiveness. AMC-HN-3, -4, -7, and -8 grow as adherent epithelioid monolayers. AMC-HN-6 exhibits multilayer stratification. Four lines are near diploid, 4 are hyperdiploid and 1 is hypodiploid. Only three express ICAM-1. All lines express the alpha 6, beta 4, and beta 1 integrin subunits but to different extent. Four, AMC-HN-1, -2, -5, and -6, express the beta 4 integrin at low levels, AMC-HN-3, -4, -7, and -9, have intermediate beta 4 expression, and AMC-HN-8 has extremely high beta 4 expression. The AMC-HN cell lines are representative in vitro models for the study of head and neck cancer biology. Our preliminary results indicate a close relationship between integrin expression and cell adhesion in vitro.     

Small treatise about e-manipulation for honest people

Information warfare is nowadays a well-known concept. However, articles are mainly split into two categories. The first one deals with how information must be managed in a system (e.g. a company or a state), in order to achieve information dominance, that is providing more and better information than the others so that they have to follow what is produced. The second one is more on how information can be used as a weapon. Dominance is one goal, but not the only one: deception, intoxication or misinformation are others. In this article, we chose the second approach. The goal when using information as a weapon is to influence a target so that it does what the attacker wants, or to cause effects. We chose also to focus on a specific battlefield: Internet. One particularly important aspect of the Internet is that it is both a container and contents. For instance, web sites are providing articles, but they are also some servers, referenced by search engines. As such, we combined this duality to increase the effects of the operations given as example. We illustrate the operation through examples, where both information is created, but also its container is improved. We show how Search Engine Optimization can be used for information warfare. Combining oriented action techniques and information based techniques make each of them much more efficient. This article shows how information warfare can be conducted on Internet. The goal is to illustrate how very few people can organize an information based attack, targeting either a company or a state for instance.     

Developmental changes in the hypoxic response of the hypoglossus respiratory motor output in vitro

The transverse brain stem slice of mice containing the pre-B?tzinger complex (PBC), a region essential for respiratory rhythm generation in vitro, was used to study developmental changes of the response of the in vitro respiratory network to severe hypoxia (anoxia). This preparation generates, at different postnatal stages [postnatal day (P)0-22], spontaneous rhythmic activity in hypoglossal (XII) rootlets that are known to occur in synchrony with periodic bursts of neurons in the PBC. It is assumed that this rhythmic activity reflects respiratory rhythmic activity. At all examined stages anoxia led to a biphasic response: the frequency of rhythmic XII activity initially increased ("primary augmentation") and then decreased ("secondary depression"). In neonates (P0-7), anoxia did not significantly affect the amplitude of integrated XII bursts. Secondary depression never led to a cessation of rhythmic activity. In mice older than P7, augmentation was accompanied by a significant increase in the amplitude of XII bursts. A significant decrease of the amplitude of XII bursts occurred during secondary depression. This depression led always to cessation of rhythmic activity in XII rootlets. The anoxia-induced response of the respiratory rhythmic XII motor output is biphasic and changes during development in a similar way to the in vivo respiratory network. Whether this biphasic response is due to a biphasic response of the respiratory rhythm generator and/or to a biphasic modulation of the XII motor nucleus remains unresolved and needs further cellular analysis. We propose that the transverse slice is a useful model system for examination of the mechanisms underlying the hypoxic response.