The mathematical model of concentration polarization coefficient in membrane transport and volume flows

In this paper, the authors investigate the membrane transport of aqueous non-electrolyte solutions in a single-membrane system with the membrane mounted horizontally. The purpose of the research is to analyze the influence of volume flows on the process of forming concentration boundary layers (CBLs). A mathematical model is provided to calculate dependences of a concentration polarization coefficient (ζ _s ) on a volume flux (J _vm ), an osmotic force (Δπ) and a hydrostatic force (ΔP) of different values. Property ζ _s ?=?f(J _vm ) for J _vm ?>?0 and for J _vm ?≈?0 and property ζ _s ?=?f(ΔC ₁) are calculated. Moreover, results of a simultaneous influence of ΔP and Δπ on a value of coefficient ζ _s when J _vm ?=?0 and J _vm ?≠?0 are investigated and a graphical representation of the dependences obtained in the research is provided. Also, mathematical relationships between the coefficient ζ _s and a concentration Rayleigh number (R _C ) were studied providing a relevant graphical representation. In an experimental test, aqueous solutions of glucose and ethanol were used.     

A segmental maximum a posteriori approach to genome-wide copy number profiling

MOTIVATION: Copy number profiling methods aim at assigning DNA copy numbers to chromosomal regions using measurements from microarray-based comparative genomic hybridizations. Among the proposed methods to this end, Hidden Markov Model (HMM)-based approaches seem promising since DNA copy number transitions are naturally captured in the model. Current discrete-index HMM-based approaches do not, however, take into account heterogeneous information regarding the genomic overlap between clones. Moreover, the majority of existing methods are restricted to chromosome-wise analysis. RESULTS: We introduce a novel Segmental Maximum A Posteriori approach, SMAP, for DNA copy number profiling. Our method is based on discrete-index Hidden Markov Modeling and incorporates genomic distance and overlap between clones. We exploit a priori information through user-controllable parameterization that enables the identification of copy number deviations of various lengths and amplitudes. The model parameters may be inferred at a genome-wide scale to avoid overfitting of model parameters often resulting from chromosome-wise model inference. We report superior performances of SMAP on synthetic data when compared with two recent methods. When applied on our new experimental data, SMAP readily recognizes already known genetic aberrations including both large-scale regions with aberrant DNA copy number and changes affecting only single features on the array. We highlight the differences between the prediction of SMAP and the compared methods and show that SMAP accurately determines copy number changes and benefits from overlap consideration.     

Influence of different Sinorhizobium meliloti inocula on abundance of genes involved in nitrogen transformations in the rhizosphere of alfalfa (Medicago sativa L.)

Inoculation of leguminous seeds with selected rhizobial strains is practised in agriculture to ameliorate the plant yield by enhanced root nodulation and nitrogen uptake of the plant. However, effective symbiosis between legumes and rhizobia does not only depend on the capacity of nitrogen fixation but also on the entire nitrogen turnover in the rhizosphere. We investigated the influence of seed inoculation with two indigenous Sinorhizobium meliloti strains exhibiting different efficiency concerning plant growth promotion on nitrogen turnover processes in the rhizosphere during the growth of alfalfa. Quantification of six target genes (bacterial amoA, nirK, nirS, nosZ, nifH and archaeal amoA) within the nitrogen cycle was performed in rhizosphere samples before nodule formation, at bud development and at the late flowering stage. The results clearly demonstrated that effectiveness of rhizobial inocula is related to abundance of nifH genes in the late flowering phase of alfalfa. Moreover, other genes involved in nitrogen turnover had been affected by the inocula, e.g. higher numbers of amoA copies were observed during flowering when the more effective strain had been inoculated. However, the respective gene abundances differed overall to a greater extent between the three plant development stages than between the inoculation variants.     

Mathematical inference of the underground clonal growth of Epipactis helleborine (L.) Crantz (Orchidaceae, Neottieae)

Epipactis helleborine (L.) Crantz (Orchidaceae, Neottieae) can spread by sexual or vegetative propagation. The choice of strategy likely depends on the environmental conditions. The rhizome is the organ of vegetative reproduction; hence, it is crucial to understand its development. Unfortunately, it is hardly possible to investigate rhizome morphology directly, since E. helleborine is a protected species in most European countries. The goal of our investigation was to infer the growth patterns of underground parts of an orchid population from long-term annual observations of its aboveground shoots. We implemented the Minimum Spanning Tree method to determine a likely set of underground connections between shoots and to simulate the annual growth of new rhizomes. Furthermore, we modelled the spatial distribution of shoots with a density kernel estimator to compare the density gradients with the direction of growth of the rhizomes. Observed shoot numbers fluctuated between 72 and 183 from year to year. Our results suggest that (1) vegetative reproduction prevails in the studied population, (2) the population consists of about a dozen clones with a diameter of up to 6 m, (3) rhizomes produce up to five new shoots at one branch end per year, (4) rhizomes develop in the direction of decreasing population density, and (5) nodes of rhizomes may produce new offshoots after up to 7 years of dormancy.     

Antimicrobial activity of lavender,tea tree and lemon oils in cosmetic preservative systems

Aims: The aim of the study was to verify the antimicrobial activity of commercial essential oils: lavender, tea tree and lemon as the components of a preservative system in oil in water body milks. Methods and Results: The inhibition efficacy of essential oils alone (0·5%), in mixtures (1%) as well as combined with the synthetic preservative 1,3‐dimethylol‐5,5‐dimethylhydantoin and a 3‐iodo‐2‐propynyl butyl carbamate mixture (0·1% and 0·2%) was tested against Staphylococcus aureus ATCC 6538, Pseudomonas aeruginosa ATCC 9027, Candida sp. ?OCK 0008 and Aspergillus niger ATCC 16404 in compliance with the standards of the European Pharmacopoeia Commission. The in vitro activity of oils determined by an impedimetric method was also compared with their activity in cosmetic preparations. Criterion A for bacteria (reduction in the inoculum by 3 logarithmic units within 7 days with no increase up to the 28th day) and fungi (reduction in the inoculum by 2 logarithmic units within 14 days with no increase up to the 28th day) was fulfilled for cosmetic formulations containing the tested essential oils with 0·2% of the synthetic preservative. The preservative concentration could be decreased to 0·1% (with preserving the same efficacy) in combination with lavender and tea tree oils at a concentration of 0·5% each. Conclusions: In all combinations of essential oils with the synthetic preservative, a synergistic effect of the preservative system components was observed, which made it possible to reduce the usable level of the synthetic preservative up to 8·5 times. Significance and Impact of the Study: To develop an effective preservative system in cosmetics in which a synthetic chemical preservative is replaced by natural essential oils.     

Biological control of Radopholus similis in banana by combined application of the mutualistic endophyte Fusarium oxysporum strain 162, the egg pathogen Paecilomyces lilacinus strain 251 and the antagonistic bacteria Bacillus firmus

The biological control efficacy of single or multiple applications of the mutualistic endophyte Fusarium oxysporum strain 162, the egg pathogen Paecilomyces lilacinus strain 251 and the antagonistic bacteria Bacillus firmus toward Radopholus similis was investigated in pot trials with banana under glasshouse conditions. R. similis was controlled substantially in single and combined applications of F. oxysporum with P. lilacinus or B. firmus. The combination of F. oxysporum and P. lilacinus caused a 68.5% reduction in nematode density whereas the individual applications reduced the density by 27.8% and 54.8% over the controls, respectively. Combined application of F. oxysporum and B. firmus was the most effective treatment in controlling R. similis on banana (86.2%), followed by B. firmus alone (63.7%). The compatibility of the biocontrol agents, as well the capacity of F. oxysporum to colonize banana roots in the absence or presence of P. lilacinus was also investigated. P. lilacinus did not adversely affect endophytic colonization by F. oxysporum. Biological control of R. similis in banana can therefore be enhanced via combined applications of antagonists with different modes of action that target different stages in the infection process. Handling editor: Ralf-Udo Ehlers     

Isolated nodal failure after chemo-radiotherapy in limited disease small cell lung cancer (LD-SCLC)

BackgroundThe irradiation volume for treatment of limited disease small cell lung cancer (LD-SCLC), are still controversial. One of the aspects of radiation volume is the use of elective nodal irradiation (ENI), which has never been subjected to randomized study in SCLC patients.AimTo review retrospectively patterns of failure in relation to the radiation field after chemoradiotherapy (CHT-RT) in patients with limited disease small cell lung cancer (LD-SCLC).Material and MethodsBetween 1997 and 2006, 117 consecutive patients with LD-SCLC received chemotherapy with sequential radiotherapy (70%) and concurrent or alternating CHT-RT (30%). All but one case had predefined elective nodal irradiation (ENI) without inclusion of supraclavicular regions. Prophylactic cranial irradiation (PCI) was administered to 39% of patients.ResultsThe median follow-up for the 20 living patients was 33 months. The overall survival at 2 years was 36% (median survival: 18 months). In-field locoregional progression was observed in 42 patients (36%). Distant metastases occurred in 71 patients (61%). Five patients (4%) developed isolated nodal failure (INF) without local progression in the supraclavicular region. Patients with INF had N3 disease more often than those without INF (60% vs 21%, p = 0.04). There was 5% RTOG grade 3 or higher early radiation toxicity.ConclusionsINF failures are rare; however, the need for extension of ENI to supraclavicular areas may be reconsidered in N3 patients.     

Interactions of Paecilomyces lilacinus strain 251 with the mycorrhizal fungus Glomus intraradices: Implications for Meloidogyne incognita control on tomato

The interactions of Paecilomyces lilacinus strain 251 with the arbuscular mycorrhizal fungus Glomus intraradices and their significance for the control of Meloidogyne incognita on tomato were investigated in greenhouse experiments. Application of P. lilacinus had no effect on the frequency and intensity of tomato root colonization by G. intraradices. Likewise, the decline of the nematophagous fungus densities after single application in soil was not affected by the presence of the mycorrhizal fungus. Single application of P. lilacinus, as pre-planting soil treatment, resulted in significant reduction of nematode damage. In contrast, mycorrhizal inoculation did not provide sufficient biocontrol. Combined application of the two agents did not enhance root protection compared to single treatments. Double treatment of mycorrhized seedlings with P. lilacinus, as seedling drench and pre-planting soil treatment, 4 and 1 week before transplanting, respectively, resulted in the highest reduction of the nematode damage. These results indicate the potential of the commercial P. lilacinus strain 251 and mycorrhiza for integration in nematode control strategies.