Growth inhibitory effect of juvenile hormone analogues on epimastigotes of Trypanosoma cruzi

Several compounds, structurally related to the insect growth regulator Fenoxycarb, exhibited interesting inhibition action to control proliferation of Trypanosoma cruzi, the parasite responsible for Chagas' disease. Some of these drugs were shown to be potent growth inhibitors of this parasite. All of these drugs had previously presented juvenoid activity on several non-related bug species such as Tenebrio molitor, Galleria mellonella, Dysdercus cingulatos, and Pyrrhocoris apterus.     

An efficient algorithm for maxdominance, with applications

Given a planar setS ofn points,maxdominance problems consist of computing, for everyp S, some function of the maxima of the subset ofS that is dominated byp. A number of geometric and graph-theoretic problems can be formulated as maxdominance problems, including the problem of computing a minimum independent dominating set in a permutation graph, the related problem of finding the shortest maximal increasing subsequence, the problem of enumerating restricted empty rectangles, and the related problem of computing the largest empty rectangle. We give an algorithm for optimally solving a class of maxdominance problems. A straightforward application of our algorithm yields improved time bounds for the above-mentioned problems. The techniques used in the algorithm are of independent interest, and include a linear-time tree computation that is likely to arise in other contexts.The research of this author was supported by the Office of Naval Research under Grants N00014-84-K-0502 and N00014-86-K-0689, and the National Science Foundation under Grant DCR-8451393, with matching funds from AT&T.This author's research was supported by the National Science Foundation under Grant DCR-8506361.     

Optical–microphysical properties of smoke haze from Siberian forest fires in summer 2012

A comprehensive experiment on the study of dynamics of optical and microphysical characteristics of submicron aerosols in the near-ground air layer was carried out in June–August of 2012 under conditions of extremely strong smoke haze originating from vast forest fires in Siberia. Variations of the spectral angular scattering coefficients and the degree of linear polarization in the visible wavelength range are studied, as well as the mass concentrations of dry fractions of aerosol and black carbon, relative content of black carbon (BC fraction), single scattering albedo, particle size distribution function, complex refractive index of the particulate matter, and parameter of condensation activity of aerosol. Peculiarities of differences between optical and microphysical characteristics of near-ground aerosol in smoke haze and under smokeless conditions are revealed. This study is important for validation of results of remote sensing of the composition of smoke haze and background atmosphere obtained from satellite data and sun photometric measurements at the Aerosol Robotic Network (AERONET).     

Microstructure of hardened gypsum pastes

Specific surface areas and pore size distribution analysis were taken as essential parameters to explore the microstructure of hardened gypsum pastes. The hydration of gypsum plaster is essentially affected by the water/plaster ratio of the mix, and by the presence of additives which might act as retarders or accelerators to the hydration process. Affecting the microstructure would mutually lead to variations of the compressive strength of the hardened pastes, and these variations are also discussed. Results are mainly expressed in terms of the solid (measured by the extent of its specific area) to the space (pore) ratios. Dual distribution of pore sizes was observed and the two groups of pores are designed as S (small) and L (large) pores. Similarities to the microstructure of hardened Portland cement pastes are indicated. Accelerators appear to function differently from retarders, and the effects of water/plaster ratios were investigated in both cases. The results obtained may carry many significant practical implications to the future use of hardened gypsum pastes.     

Thermal decomposition and pore structure of pure and doped stannic oxide gel

The surface properties of a stannic oxide gel and its thermal dehydration products obtained both in vacuo and in the presence of air in the temperature range 100–600°C have been examined by N₂ adsorption. Phase and structural changes have been followed by differential thermal analysis and X-ray diffractometry. Complete pore structure analysis showed that samples dehydrated at or below 250°C were microporous. Above 250°C the pores were found to widen with increase of temperature, the widening occurring concurrently with the crystallisation process. Doping with cations of lower valency (Li⁺ and Al³⁺) than the host cation (Sn⁴⁺) had little effect on the pore structure and specific surface area for the low temperature samples (≤250°), whereas at higher temperatures, e.g. 600°C, it increased the specific area remarkably. The dope ions produce oxygen vacancies and hinder or retard sintering in SnO₂.     

Morphology and microstructure of autoclaved clinker and slag-lime pastes in presence and in absence of silica sand

Development of microstructure in four hydrothermal reactions has been undertaken using scanning electron microscopy. These are clinker, clinker-sand, slag-lime and slag-lime-sand hydrothermal reactions. The microstructure of clinker hydration products displayed crumpled foils and tabular masses of calcium silicate hydrates; few cubic crystals of hydrogarnet appeared only during the initial stage of the reaction. In clinker-sand mixture the C-S-H phase was the only product identified. In slag-lime hydration the microstructure displayed both of the hydrogarnet crystals and the C-S-H phase. The hydration of slag-lime-sand mixture (an optimum composition) was associated with the formation of ill-crystallized tobermorite and crystalline 11A tobermorite as the main products.     

Dimensions of the average pore,the number of pores,and the surface area of hardened Portland cement paste

In the course of their small angle x-ray scattering work, Winslow and Diamond also calculated the radius of gyration of the pores. Using its value for a paste, Diamond adopted two models for the average pore: a sphere and a cylinder of equal height and diameter. This model leads to absurd values for the surface area of the paste. Using a cylindrical model, and the radius of gyration plus the hydraulic radius, the present authors calculated for a similar paste the dimensions of the average pore and obtained the values: $\text{diameter}\text{= 47.2}\text{A}\text{?}\text{,}\text{length}\text{= 466}\text{A}\text{?}$. The number of pores per gram of paste was 2.26 × 10¹⁷. The paper also discusses the surface area of hardened paste, and points out the extremely important contributions of Winslow and Diamond to the subject.     

Engineering of functional supramacromolecular complexes of proteins (enzymes) using reversed micelles as matrix microreactors

The size of the inner water cavity of reversed micelles formedin a triple system ‘water-surfactant-organic solvent’can be widely varied by changing the degree of surfactant hydration.This gives grounds to use reversed micelles as matrix microreactorsfor the design of supramolecular complexes of proteins. Usingultracentrifugation analysis, it has been demonstrated thatthe oligomeric composition of various enzymes (ketoglutaratedehydrogenase, alkaline phosphatase, lactic dehydrogenase, glyceraldehyde-3-phosphatedehydrogenase) solubilized in reversed micelles of Aerosol OT[sodium bis(2-ethylehexyl)sulfosuccinate] in octane changesupon variation of the degree of hydration. An oligomeric complexforms under conditions when the radius of the micelle innercavity is big enough to incorporate this complex as a whole.At lower degrees of hydration the micelles ‘uncouple’such complexes to their components. The catalytic propertiesof various oligomeric complexes have been studied. Possibilitiesof using reversed micelles for the separation of subunits ofoligomeric enzymes under non-denaturating conditions have beendemonstrated. In particular, the isolated subunits of alkalinephosphatase, lactic dehydrogenase and glyceralde-hyde-3-phosphatedehydrogenase have been found to be active in Aerosol OT reversedmicelles. The dependences of the catalytic activity of oligomericenzymes represent saw-like curves. The maxima of the catalyticactivity observed at these curves relate to the functioningof various oligomeric forms of an enzyme. The radii of the micelleinner cavity under conditions when these maxima are observedcorrelate with the linear dimensions of the enzyme oligomericforms. Correlation of the position of a maximum with the shapeof an oligomeric complex is discussed.