Search

Purpose: Identify soil properties involved in the adsorption of the bacteriophages (phages) ΦITL-1 and ΦRSP, analyzing different soils and substrates used for greenhouse tomato crops. Methods: Soil samples were collected from greenhouses in Mexico Central, and soil properties were obtained using the NOM-021-RECNAT-2000. For phage adsorption, soil or substrate was mixed with a phage solution, using three different Water Retention Capacity (WRC) levels, incubated under shaking to room temperature, and finally, the plaque-forming units were counted for each phage by titration. Results: The phage elution counts showed that the amount of aqueous solution in the mixture is inversely related to the number of viral particles adsorbed on the soil. Furthermore, the soils with a sandy texture had lower adsorption of phages in comparison with the rest of the soils analyzed, which have clay, clay loam, and sandy loam textures. A correlation analysis showed that soil pH and texture are the properties that most influenced phage adsorption. Finally, a principal component analysis showed that Cation Exchange Capacity (CEC) has a direct relationship with phage adsorption. Conclusion: In the present study, we demonstrated that soil texture, pH, CEC, and WRC are determinant variables that affect the adsorption of R. solanacearum phages ΦITL-1 and ΦRSP. Furthermore, we propose that the responsible mechanism may be due to the richness of cations in the soil, which could imply an electrostatic interaction with some exposed phage proteins. These results highlight the influence of soil properties on biocontrol strategies based on phages, which try to reduce the impact of soil-borne bacterial phytopathogens. [ABSTRACT FROM AUTHOR]

Harmony search algorithm and its variants have been used in several applications in medicine, telecommunications, computer science, and engineering. This article reviews the global and multi-objective optimization for chemical engineering using harmony search. The main features of the HS method and several of its popular variants and hybrid versions including their relevant algorithm characteristics are described and discussed. A variety of global and multi-objective optimization problems from chemical engineering and their resolution using HS-based methods are also included. These problems involve thermodynamic calculations (phase stability analysis, phase equilibrium calculations, parameter estimation, and azeotrope calculation), heat exchanger design, distillation simulation, life cycle analysis, and water distribution systems, among others. Remarks on future developments of HS and its related algorithms for global and multi-objective optimization in chemical engineering are also provided in this review. HS is a reliable and promising stochastic optimizer to resolve challenging global and multi-objective optimization problems for process systems engineering. [ABSTRACT FROM AUTHOR]

The interaction between calf thymus DNA and the gemini surfactants N,N′-[α,̉-phenylenebis(methylene)bis [N,N′-dimethyl-N-(1-hexadecyl)]-ammonium dibromide], p-16-Ph-16 (α = 1, ̉ = 3) and m-16-Ph-16 (α = 1, ̉ = 2), has been investigated via circular dichroism, fluorescence and UV-vis spectroscopy, zeta potential, dynamic light scattering, and AFM microscopy. Measurements were carried out in aqueous media at different molar ratios, R = (C16-Ph-16)/CDNA and C16-Ph-16 always below the critical micellar concentration (CMC) of the surfactant. Under these conditions, DNA undergoes two reversible conformational changes, compaction and decompaction, due to interaction with the surfactant molecules at low and high molar ratios, respectively. The extent of such conformational changes is correlated with both the degree of surfactant partial intercalation, and the size and charge of the surfactant aggregates formed, in each case. Comparison of the results shows that the para-form of the surfactant intercalates into the DNA to a major extent; therefore, the compaction/decompaction processes are more effective. Among these, the structure of the resulting 16-Ph-16/DNA decompacted complex is worthy of note. For the first time it can be demonstrated that the partial intercalation of the 16-Ph-16 gemini surfactants induces the formation of triplex DNA-like structures at a high R ratio. [ABSTRACT FROM AUTHOR]

Copyright of Revista Colombiana de Biotecnología is the property of Universidad Nacional de Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of International Journal of Cosmetic Science is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Childhood diarrhoea is a leading cause of morbidity and mortality in Nicaragua. Amongst the risk factors for its transmission are 'poor' hygiene practices. We investigated the effect of a large number of hygiene practices on diarrhoeal disease in children aged <2 years and validated the technique of direct observation of hygiene behaviour.Methods: A prospective follow-up study was carried out in a rural zone of Nicaragua. From the database of a previously conducted case-control study on water and sanitation 172 families were recruited, half of which had experienced a higher than expected rate of diarrhoea in their children and the other half a lower rate. Hygiene behaviour was observed over two mornings and diarrhoea incidence was recorded with a calendar, filled out by the mother, and collected every week for 5 months.Results: Of 46 'good' practices studied, 39 were associated with a lower risk of diarrhoea, five were unrelated and only for two a higher risk was observed. Washing of hands, domestic cleanliness (kitchen, living room, yard) and the use of a diaper/underclothes by the child had the strongest protective effect. Schooling (>3 years of primary school) and better economic position (possession of a radio) had a positive influence on general hygiene behaviour, education having a slightly stronger effect when a radio was present. Individual hygiene behaviour appeared to be highly variable in contrast with the consistent behaviour of the community as a whole. Feasible and appropriate indicators of hygiene behaviour were found to be domestic cleanliness and the use of a diaper or underclothes by the child.Conclusion: A consistent relationship between almost all hygiene practices and diarrhoea was detected, more schooling producing better hygiene behaviour. The high variability of hygiene behaviour at the individual level requires repeated observations (at least two) before and after the hygiene education in the event one wants to measure the impact of the campaign on the individual. [ABSTRACT FROM AUTHOR]

Nucellus-derived embryogenic callus cultures of Salustiana sweet orange were subjected to cryoconservation assays. Cryoprotection with 10%(vol/vol) dimethylsulfoxide, freezing by slow cooling and thawing by fast warming was suitable to recover viable growing cultures and whole plants through embryogenesis. Evaluation of liquid phase R1 and solid phase R2 cooling rates using a programmable freezing unit indicated that 100% of embryogenic cultures survived when frozen using a range of cooling rates ( R1 not above 0.5°C min–1 and R2 not above 1°C min 1) and thawed by fast warming. Storage up to 2 years in liquid nitrogen did not affect the growth of the cryopreserved cultures and the recovery of whole plants. Cultures of four cultivars of sweet orange ( C. sinensis Osb.), three cultivars of grapefruit ( C. paradisi Macf.), and one cultivar each of lemon [ C. limon (L.) Burm. f.], Cleopatra mandarin ( C. reshni Hort. ex Tan.), sour orange (C. aurantium L.) and Mexican lime [ C. aurantifolia (Christm.) Swing.] have been successfully cryopreserved. Problems using a viability assessment using fluorescein diacetate staining are discussed. [ABSTRACT FROM AUTHOR]

A number of halomethyl-1,2,3-triazole derivatives have been tested for their effect on ICR Swiss female mice bearing the Ehrlich carcinoma ascites (ECA) tumor. Two of these compounds, namely 4-bromomethyl-1-(2,3,4,6-tetra-0-acetyl-β-D-glucopyranosyl)-1,2,3-triazole and 4-iodomethyl-1-(2,3,4,6-tetra-0-acetyl-β-D-glucopyranosyl)-1,2,3-triazole, referred to here as compounds H and K, respectively, promoted a significant increase in the median survival time (145% and 195%) when injected IP for 9 consecutive days at doses of 75 mg/kg/injection and 100 mg/kg/injection, respectively. DNA synthesis, as measured by (methyl-H)thymidine incorporation into trichloroacetic acid-precipitated material, was always inhibited by all the triazole derivatives to a greater extent than the incorporation of (5,6-H)uridine, (5-H)proline, and (6-H)-glucose. Moreover, inhibition of DNA synthesis was complete and irreversible following exposure to selected triazole derivatives. Compounds H and K inhibited the incorporation of di(H)methyl sulfate by ECA cells. In addition, compound K promoted the release of radioactivity associated with trichloroacetic acid-insoluble material coming from (8-H)guanosine-prelabeled cells. This release of radioactivity did not occur when cells were prelabeled with (methyl-H)thymidine. It is concluded from these results that these triazole derivatives act as alkylating agents. [ABSTRACT FROM AUTHOR]

Copyright of Boletín Médico del Hospital Infantil de México is the property of Publicidad Permanyer SLU and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)