Causality between pillars of sustainable development: Global stylized facts or regional phenomena?

Since the Brundtland report, most governments have committed themselves to sustainable development. For this purpose, different global and national organizations and institutions have tried to find the relationships, and especially causalities, between sustainability pillars, which are interesting for them from a policy point of view. With respect to their findings, some questions need to be answered before appropriate policies can be formulated. Are causalities between sustainability pillars global stylized facts or regional phenomena? Can countries with different characteristics follow the same rules, or are causalities between the pillars sensitive to the regional and intrinsic features of countries? Using principal component analysis for the construction of sustainability indicators and the Granger causality model (GMM approach) for testing the causalities between sustainability pillars in different samples, this study finds that causal patterns among the pillars of sustainability are completely sensitive to the characteristics of the countries that are grouped. Therefore, it is recommended that researchers concentrate more on homogeneous case studies and avoid generalizations of causal relationships between sets of heterogeneous countries.     

Estimation of proteins in the presence of polyethylenimine

Polyethylenimine (PEI) interferes strongly in all commonly employed protein estimation assays. Here, a strategy to remove this interference is developed. Polyethylenimine is selectively removed by adsorption from a mixture containing PEI and lysozyme using carboxymethyl-cellulose, a cation-exchange resin between an ionic strength of 0.35–1 M (pH 6.0), conditions under which lysozyme remains in solution and can be accurately estimated.     

Size-dependent neurotoxicity of β-amyloid oligomers

The link between the size of soluble amyloid β (Aβ) oligomers and their toxicity to rat cerebellar granule cells (CGC) was investigated. Variation in conditions during in vitro oligomerization of Aβ_1-42 resulted in peptide assemblies with different particle size as measured by atomic force microscopy and confirmed by dynamic light scattering and fluorescence correlation spectroscopy. Small oligomers of Aβ_1-42 with a mean particle z-height of 1-2 nm exhibited propensity to bind to phospholipid vesicles and they were the most toxic species that induced rapid neuronal necrosis at submicromolar concentrations whereas the bigger aggregates (z-height above 4-5 nm) did not bind vesicles and did not cause detectable neuronal death. A similar neurotoxic pattern was also observed in primary cultures of cortex neurons whereas Aβ₁₋₄₂ oligomers, monomers and fibrils were non-toxic to glial cells in CGC cultures or macrophage J774 cells. However, both oligomeric forms of Aβ_1-42 induced reduction of neuronal cell densities in the CGC cultures.     

New Evidence for Dimerization-Dependence of the Activity of Candida Rugosa Lipase

The specific activity of the lipase of Cundidu rugosu decreases with increasing enzyme concentration even in the presence of soluble substrates. Data about the hydrolysis of 2-chloropropionic acid ethyl ester (CPEE) had suggested that this phenomenon may be caused either by dimerization of the lipase or by adsorption onto the reactor wall. In order to distinguish between both models, experiments were carried out by changing not only the enzyme concentration but also the wetted surface area of the reaction vessel. These novel data reveal that wetted glass surfaces are of only minor importance - if any. Thus, the decrease of activity seems to be caused by some kind of dimerization of the lipase. In addition, it is shown that adsorption onto hydrophobic surfaces can have a dramatic effect on the specific activity. In the presence of large hydrophobic surface areas the specific activity is found to be almost as high as that observed in the presence of insoluble substrate. The analysis of a commonly used test system for lipase activity measurements based on triacetin hydrolysis exhibits a similar activity-enzyme concentration dependence.     

The adsorption of poly (vinyl alcohol) on the hydroxylated β-cristobalite

The adsorption of poly (vinyl alcohol) with different chain lengths on a hydroxylated β-cristobalite (100) surface is studied via molecular simulations. The relative dielectric constant is selected to be 1 and 78 to mimic in vacuum and in solution environment, respectively. Different configurations and dynamic properties are found in the two absolutely different environments, showing that the solvent condition plays an important role in the process of chain adsorption and diffusion on a surface. In equilibrium, the chain possesses (partial) ordered configuration in vacuum condition.     

Towards the Molecular Mechanism of Pulmonary Surfactant Protein SP-B: At the Crossroad of Membrane Permeability and Interfacial Lipid Transfer

Pulmonary surfactant is a lipid-protein complex that coats the alveolar air-liquid interface, enabling the proper functioning of lung mechanics. The hydrophobic surfactant protein SP-B, in particular, plays an indispensable role in promoting the rapid adsorption of phospholipids into the interface. For this, formation of SP-B ring-shaped assemblies seems to be important, as oligomerization could be required for the ability of the protein to generate membrane contacts and to mediate lipid transfer among surfactant structures. SP-B, together with the other hydrophobic surfactant protein SP-C, also promotes permeability of surfactant membranes to polar molecules although the molecular mechanisms underlying this property, as well as its relevance for the surface activity of the protein, remain undefined. In this work, the contribution of SP-B and SP-C to surfactant membrane permeability has been further investigated, by evaluation of the ability of differently-sized fluorescent polar probes to permeate through giant vesicles with different lipid/protein composition. Our results are consistent with the generation by SP-B of pores with defined size in surfactant membranes. Furthermore, incubation of surfactant with an anti-SP-B antibody not only blocked membrane permeability but also affected lipid transfer into the air-water interface, as observed in a captive bubble surfactometer device. Our findings include the identification of SP-C and anionic phospholipids as modulators required for maintaining native-like permeability features in pulmonary surfactant membranes. Proper permeability through membrane assemblies could be crucial to complement the overall role of surfactant in maintaining alveolar equilibrium, beyond its biophysical function in stabilizing the respiratory air-liquid interface.     

扩张柱床吸附层析与固定柱床层析纯化单克隆抗体的比较

为满足Ⅰ类新药二期临床的药品需求量,单抗生产由实验室规模扩大到中试规模,在目标产品的下游纯化工艺中,采用扩张柱床吸附技术代替一期临床实验室规模方法中的澄清、浓缩、和最初的疏水层析,其后的纯化步骤保持不变。由于采用新的纯化路线,使得制备周期缩短23,处理能力由100ml小鼠腹水扩大至18～50L杂交瘤细胞培养液,回收率提高20%以上,并很容易根据需要线性放大规模,为单抗的的产业化提供了更为简便和高效的下游纯化模式。     

Maximum entropy analysis of oversampled data problems

An algorithm for the solution of the Maximum Entropy problem is presented, for use when the data are considerably oversampled, so that the amount of independent information they contain is very much less than the actual number of data points. The application of general purpose entropy maximisation methods is then comparatively inefficient. In this algorithm the independent variables are in the singular space of the transform between map (or image or spectrum) and data. These variables are much fewer in number than either the data or the reconstructed map, resulting in a fast and accurate algorithm. The speed of this algorithm makes feasible the incorporation of recent ideas in maximum entropy theory (Skilling 1989 a; Gull 1989). This algorithm is particularly appropriate for the exponential decay problem, solution scattering, fibre diffraction, and similar applications.