Chlamydial pneumonia of infancy: further clinical observations

Two patients with chlamydial pneumonia of infancy are described. One recovered spontaneously without any specific antichlamydial treatment. The other, prior to a belated antimicrobial therapy, developed a persistent and protracted respiratory illness characterized by wheezing. Our observations suggest that: (1) untreated chlamydial pneumonia of infancy may spontaneously resolve, or may become a persistent and protracted disease, and (2) wheezing may be a very prominent manifestation of the disease and should be differentiated from wheezing due to bronchiolitis and bronchial asthma.     

The lost art of short communications in academia

Scientometrics - Short communications are an integral part of academic journal publishing since they serve as a forum for scholarly debate on recently published journal articles. Their prestige and...     

Evaluation of the corrosion resistance of Ni-Co-B coatings in simulated PEMFC environment

The corrosion resistance behavior of Ni-Co-B coated carbon steel, Al 6061 alloy and 304 stainless steel was evaluated in simulated proton exchange membrane fuel cell (PEMFC) environment. The phase structure of the NiCoB based alloy was determined by Rietveld analysis. The PEMFC environment was constituted of 0.5 M H₂SO₄ at 60 °C and the evaluation techniques employed included potentiodynamic polarization, linear polarization resistance, open circuit potential measurements and electrochemical impedance spectroscopy. The results showed that in all cases the corrosion resistance of the Ni-Co-B coating was higher than that of the uncoated alloys; about two orders of magnitude with respect to carbon steel and an order of magnitude compared to 304 stainless steel. Except for the uncoated 304 type stainless steel, the polarization curves for the coated specimens did not exhibit a passive region but only anodic dissolution. The corrosion potential value, E_corr, was always nobler for the coated samples than for the uncoated specimens. This was true for the stainless steel in the passive region, but in the active state for the carbon steel and Al 6061 alloy. The corrosion of the underlying alloy occurred due to filtering of the solution through coating defects like microcracks, pinholes, etc. During the filtering process the E_corr value of the coating decreased slowly until it reached a steady state value, close to the E_corr value of the underlying alloy.     

Metal Organic Framework Crystals in Mixed‐Matrix Membranes: Impact of the Filler Morphology on the Gas Separation Performance

Mixed‐matrix membranes comprising NH₂‐MIL‐53(Al) and Matrimid or 6FDA‐DAM have been investigated. The metal organic framework (MOF) loading has been varied between 5 and 20 wt%, while NH₂‐MIL‐53(Al) with three different morphologies, nanoparticles, nanorods, and microneedles has been dispersed in Matrimid. The synthesized membranes have been tested in the separation of CO₂ from CH₄ in an equimolar mixture. At 3 bar and 298 K for 8 wt% MOF loading, incorporation of NH₂‐MIL‐53(Al) nanoparticles leads to the largest improvement compared to nanorods and microneedles. The incorporation of the best performing filler, i.e., NH₂‐MIL‐53(Al) nanoparticles, into the highly permeable 6FDA‐DAM has a larger effect, and the CO₂ permeability increases up to 85% with slightly lower selectivities for 20 wt% MOF loading. Specifically, these membranes have a permeability of 660 Barrer with a CO₂/CH₄ separation factor of 28, leading to a performance very close to the Robeson limit of 2008. Furthermore, a new non‐destructive technique based on Raman spectroscopy mapping is introduced to assess the homogeneity of the filler dispersion in the polymer matrix. The MOF contribution can be calculated by modeling the spectra. The determined homogeneity of the MOF filler distribution in the polymer is confirmed by focused ion beam scanning electron microscopy analysis.     

Protection of carbon steel against hot corrosion using thermal spray Si- and Cr-base coatings

A Fe75Si thermal spray coating was applied on the surface of a plain carbon steel baffle plate. Beneath this coating, a Ni20Cr coating was applied to give better adherence to the silicon coating. The baffle was installed in the high-temperature, fireside, corrosion zone of a steam generator. At the same time, an uncoated 304 stainless steel baffle was installed nearby for comparison. For 13 months the boiler burned heavy fuel oil with high contents of vanadium. The samples were studied employing scanning electron microscopy, x-ray microanalysis, and x-ray diffraction techniques. After that, it was possible to inspect the structural state of the components, and it was found that the stainless steel baffle plates were destroyed almost completely by corrosion, whereas the carbon steel coated baffle plate did not suffer a significant attack, showing that the performance of the thermal spray coating was outstanding and that the coating was not attacked by vanadium salts of the molten slag.     

Ozonation of black‐table‐olive industrial wastewaters: effect of an aerobic biological pretreatment

The present work is a study of oxidative degradation of the organic matter present in the washing waters from the black‐table‐olive industry. This oxidation is performed by an ozonation process, by an aerobic biological degradation process, and by another ozonation of biologically pretreated washing waters. In the ozonation process, a second‐order kinetic reaction with respect to ozone and COD or aromaticity has been deduced. The kinetic rate constants were correlated as a function of temperature by Arrhenius‐type equations. In the aerobic biological treatment, a kinetic study was performed using the Contois model, giving a value of 4.8 10⁻² h⁻¹ for the kinetic bioreaction constant. Likewise, a cell yield coefficient of 0.30 g VSS g COD⁻¹ and a kinetic constant for the endogenous metabolisme of 1.2 10⁻² h⁻¹ were deduced. Finally, in the ozonation of biologically pretreated wash‐waters, the deduced kinetic rate constants for COD and aromaticity were, respectively, 4.5 and 2.4 times higher that those corresponding to the ozonation of wash‐waters without biological pretreatment. © 2000 Society of Chemical Industry     

Treatment of olive mill wastewaters by ozonation,aerobic degradation and the combination of both treatments

The degradation of the pollutant organic matter present in olive oil mill wastewaters (OMW) is carried out by a single ozonation, a single aerobic degradation, and the combination of two successives steps: an ozonation followed by an aerobic degradation, and an aerobic degradation followed by an ozonation. In both single processes, the removal of this contaminant load is followed by means of global parameters which are directly related to the concentration of organic compounds in those effluents: chemical oxygen demand and total aromatic and phenolic contents. In the ozonation, an approximate kinetic study is performed which leads to the evaluation of the apparent kinetic constants for the aromatic reduction, k_A. In the aerobic degradation, the kinetic study is conducted by using the Grau model, which is applied to the experimental data, and leads to the determination of the kinetic parameters of this model, K₂ and n. In the combined processes, a higher COD global reduction is obtained by the successive stages, and an improvement in the removal of the organic material during the second treatment of both processes due to the pretreatment conducted is also observed. This enhancement is shown by an increase of the kinetic parameters (K₂ and n in the aerobic degradation of the pre‐ozonated wastewaters; the apparent constant k_A in the ozonation of the wastewaters preliminary fermented aerobically), in relation to the values obtained for them in the single processes carried out at the same operating conditions. © 1999 Society of Chemical Industry     

Somatostatin and Astroglial Involvement in the Human Limbic System in Alzheimer’s Disease

Alzheimer’s disease (AD) is the most prevalent neurodegenerative disease in the elderly. Progressive accumulation of insoluble isoforms of amyloid-β peptide (Aβ) and tau protein are the major neuropathologic hallmarks, and the loss of cholinergic pathways underlies cognitive deficits in patients. Recently, glial involvement has gained interest regarding its effect on preservation and impairment of brain integrity. The limbic system, including temporal lobe regions and the olfactory bulb, is particularly affected in the early stages. In the early 1980s, the reduced expression of the somatostatin neuropeptide was described in AD. However, over the last three decades, research on somatostatin in Alzheimer’s disease has been scarce in humans. Therefore, the aim of this study was to stereologically quantify the expression of somatostatin in the human hippocampus and olfactory bulb and analyze its spatial distribution with respect to that of Aβ and au neuropathologic proteins and astroglia. The results indicate that somatostatin-expressing cells are reduced by 50% in the hippocampus but are preserved in the olfactory bulb. Interestingly, the coexpression of somatostatin with the Aβ peptide is very common but not with the tau protein. Finally, the coexpression of somatostatin with astrocytes is rare, although their spatial distribution is very similar. Altogether, we can conclude that somatostatin expression is highly reduced in the human hippocampus, but not the olfactory bulb, and may play a role in Alzheimer’s disease pathogenesis.     

Wetting of the (0001) <Emphasis Type="Italic">α</Emphasis>-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> Sapphire Surface by Molten Aluminum: Effect of Surface Roughness

The wetting of molten aluminum on the “c”-plane (0001) of single-crystal α-Al₂O₃ (sapphire) was studied by the sessile drop technique from 800 °C (1073 K) to 1200 °C (1473 K). Systematically increasing the (0001) surface roughness by SiC abrasion increased the wetting contact angle, resulting in reduced wetting. The surface roughness factor R originally defined by Wenzel, was determined as a function of the abrasion, temperature, and time. The wetting decreases as the surface roughness increases. Rough surfaces also create time and temperature effects on wetting, changing those for a smoothly polished surface. The existence of a high-temperature surface structural transition for (0001) of α-Al₂O₃, which has been previously suggested, was confirmed. Increased roughness R accents the effect of the surface structural transition, increasing the wetting contact angle changes during the transition.