Subanesthetic concentrations of isoflurane suppress learning as defined by the category-example task

It has been shown that chronic oral steroid therapy (ST) does not induce respiratory muscle dysfunction in normal and asthmatic subjects. As corticosteroids are sometimes chronically used in the treatment of the patients with chronic obstructive pulmonary disease (COPD), the aim of our study was to verify whether ST could cause respiratory muscle impairment and, since ST also affects the central nervous system, whether ST could influence the ventilatory pattern. We retrospectively studied 12 COPD patients (group A), on long-term therapy (for at least 4 consecutive months, range 4-18 months) with an oral steroid, deflazacort, 15 mg.d-1. The subjects were strictly matched, with regard to age, sex, height, weight, forced expiratory volume in one second (FEV1), residual volume (RV), arterial oxygen tension (PaCO2), arterial carbon dioxide tension (PaCO2) and pH, with 12 COPD patients (Group B) who had never taken oral steroids. To assess respiratory muscle strength, we measured maximal inspiratory (MIP) and expiratory (MEP) pressures, while mouth occlusion pressure (P0.1) was employed to assess neuromuscular drive; ventilatory pattern and airway impedence were also evaluated. Effectiveness of ST was confirmed by the plasmatic levels of endogenous cortisol. No significant differences were observed between the two groups with regard to MIP (A 72.2 +/- 9.7 vs B: 70 +/- 7.2 cmH2O) and MEP (A 91.6 +/- 10.5 vs B 94.4 +/- 7.6 cmH2O) whilst P0.1 was significantly higher in group A (2.6 +/- 0.3 cmH2O) than in group B (1.8 +/- 0.1 cmH2O). No significant differences were found among all the ventilatory parameters, but the impedence was significantly higher in group A.(ABSTRACT TRUNCATED AT 250 WORDS)     

Modification of oxidizing activity of Thiobacillus ferroxidans by some particulate solids

Different particulate solids such as glass powder, various types of activated carbon and bentonite suspended in Thiobacillus ferrooxidans cultures produce very different effects on the oxidizing activity of the microorganism. The atmospheric oxygen uptake by Thiobacillus ferrooxidans in Warburg respirometer flasks containing 9K medium with ferrous sulfate as energy source and suspended bentonite is 2.8 times that in the absence of solids. The dissolution rate of pure pyrite in 250 cm³ shake flasks containing 9K medium and bentonite is considerably enhanced over that where the only solid phase is pyrite. Conversely, the oxidizing ability of the microorganism seems to be inhibited by all the activated carbons tested. The effect of ground glass seems to be related to its particle size distribution. Implications for the bioleaching of sulfide ores and coal pyrite are discussed in the light of current knowledge on the adsorption of Thiobacillus ferrooxidans cells on solid surfaces.     

油罐水高智能测量装置研究

原油在开采和加工过程中必须除去原油中的水分,以减少在输送和储存过程中的浪费,确保输送、加工过程中的安全。因此,油罐底部水在线监测对原油生产和管理具有重要意义。油罐水高智能测量装置通过石油密度计、浮球式液位仪、压力传感器的在线测得参数,利用这3个参数关系,通过PLC编程计算实现对油罐中油水混合状态下底部水高的在线实时自动监测。这对于在石油脱水和存储过程中及时排放罐底水提供技术支持。     

Oral health assessment in dogs: study design and results

The authors have conducted a large number of canine dental studies during the past six years. Study methodologies have been driven by the need for statistical validation of results, requiring the participation of large numbers of animals in each study. For plaque, stain, and calculus evaluations, a "clean tooth" model was used, in which formation of these substrates was assessed days to weeks after an initial coronal cleaning. A primary goal of the studies described was to validate the study designs used--that is, to use accepted plaque-, calculus-, and stain-controlling agents to test whether the study methods could detect differences between treated and untreated groups. The results of clinical studies show that the methods described can be used to identify plaque, calculus, and stain control attributable to chemical agents, oral hygiene aids, and consumable products.     

How evolution makes proteins fold quickly

Sequences of fast-folding model proteins (48 residues long on a cubic lattice) were generated by an evolution-like selection toward fast folding. We find that fast-folding proteins exhibit a specific folding mechanism in which all transition state conformations share a smaller subset of common contacts (folding nucleus). Acceleration of folding was accompanied by dramatic strengthening of interactions in the folding nucleus whereas average energy of nonnucleus interactions remained largely unchanged. Furthermore, the residues involved in the nucleus are the most conserved ones within families of evolved sequences. Our results imply that for each protein structure there is a small number of conserved positions that are key determinants of fast folding into that structure. This conjecture was tested on two protein superfamilies: the first having the classical monophosphate binding fold (CMBF; 98 families) and the second having type-III repeat fold (47 families). For each superfamily, we discovered a few positions that exhibit very strong and statistically significant "conservatism of conservatism"-amino acids in those positions are conserved within every family whereas the actual types of amino acids varied from family to family. Those amino acids are in spatial contact with each other. The experimental data of Serrano and coworkers [Lopez-Hernandez, E. & Serrano, L. (1996) Fold. Des. (London) 1, 43-55]. for one of the proteins of the CMBF superfamily (CheY) show that residues identified this way indeed belong to the folding nucleus. Further analysis revealed deep connections between nucleation in CMBF proteins and their function.     

Synthesis of the nitrogen-fixing enzyme system in oligonitrophilic bacteria

Oligonitrophilic bacteria were cultivated on a medium containing only 2.5--10.0 mg/litre of nitrogen compounds. They assimilated elementary nitrogen only after utilization of these nitrogen compounds during growth and formation of nitrogen-fixing enzyme system. Their cells grown on a medium containing high concentrations of bound nitrogen did not fix nitrogen during further incubation in the atmosphere of 15N; therefore, the enzymes involved in nitrogen fixation were induced. These organisms are characterized by diauxia during their growth on media containing "start" doses of nitrogen. Enzymes catalysing nitrogen fixation in azotobacter are also induced. But, contrary to oligonitrophilic bacteria, the azotobacter does not require nitrogen compounds in the medium in order to adapt to molecular nitrogen, and its growth curve is not of a biphasal character. These data and the evidence of other authors suggest that all nitrogen-fixing microorganisms are characterized by the induced, not constitutive, enzymes involved in reduction of molecular nitrogen.     

Yield surface linearization in elastoplastic analysis

A method for the historical elastoplastic analysis of plane frames under the assumption of small deformation theory is presented. Interaction of bending moment and axial force is taken into account. A major feature of the procedure lies in the piecewise linearization of the convex nonlinear yield surface, thereby guaranteeing the satisfaction of both equilibrium and yield conditions. Local unloading can also be catered for. A computer program based on this technique has been written and three simple numerical examples are given to illustrate its capabilities.     

Molecular basis of open-angle glaucoma in Italy

Glaucoma is a group of ocular diseases characterized by an optic neuropathy in which degeneration of retinal ganglion cells leads to a characteristic excavation of the optic nerve head. Primary open-angle glaucoma (POAG) can be subdivided into two groups according to age of onset:- 1. the more common middle- to late-age onset, chronic open-angle glaucoma (COAG) diagnosed after the age of 40 years; 2. the rarer juvenile open-angle glaucoma (JOAG), which is diagnosed between the age of 3 years and early adulthood. Recently, the gene coding for the trabecular meshwork-induced glucocorticoid response protein (TIGR), located in chromosome 1 (1q23-25), was found mutated in patients affected by POAG. In this work we describe the clinical and molecular genetic features of several Italian families affected by autosomal dominant POAG, collected in various regions of Italy.     

Evaluation of in vitro antioxidant properties of some traditional Sardinian medicinal plants: Investigation of the high antioxidant capacity of Rubus ulmifolius

The antioxidant capacities of 11 botanical species used in the tradition of Sardinia as teas beverages or as decoction for medicinal purposes were evaluated using different in vitro methods (BR, TEAC, DPPH and FC). Among the various species, Rubus ulmifolius, resulted the more active with all the used methods. Phytochemical investigation on the extract yields in the isolation of several phenolic compounds namely caffeic acid, ferulic acid, quercetin-3-O-glucuronide, kaempferol-3-O-glucuronide, kaempferol-3-O-(6″-p-coumaroyl)-β-d-glucopyranoside, kaempferol-3-O-(6″-caffeoyl)-β-d-glucopyranoside, chlorogenic acid, 4-caffeoylquinic acid and 5-caffeoylquinic acid. The antioxidant activity of isolated compounds was also evaluated.     

高温焙烧高钛渣工艺的试验研究

以云南地区钛铁矿富集得到的高钛渣为原料,置于加热装置内焙烧,在1000℃下加热处理20min,利用XRD、SEM研究了高温焙烧对高钛渣相组成和微观结构的影响.结果表明:在高温条件下高钛渣中的锐铁型TiO2转化为金红石型TiO2.提出了一种高温焙烧高钛渣的新工艺,从生产源头消除了对环境的污染,实现钛资源的可持续发展.