Enhanced quality factors and force sensitivity by attaching magnetic beads to cantilevers for atomic force microscopy in liquid

Dynamic-mode atomic force microscopy (AFM) in liquid remains complicated due to the strong viscous damping of the cantilever resonance. Here we show that a high-quality resonance (Q>20) can be achieved in aqueous solution by attaching a microgram-bead at the end of the nanogram-cantilever. The resulting increase in cantilever mass causes the resonance frequency to drop significantly. However, the force sensitivity --- as expressed via the minimum detectable force gradient --- is hardly affected, because of the enhanced quality factor. Via the enhancement of the quality factor, the attached bead also reduces the relative importance of noise in the deflection detector. It can thus yield an improved signal-to-noise ratio when this detector noise is significant. We describe and analyze these effects for a set-up which includes magnetic actuation of the cantilevers and which can be easily implemented in any AFM system that is compatible with an inverted optical microscope.Comment: The following article has been accepted by Journal of Applied Physics. After it is published, it will be found at http://jap.aip.org

Exploring the intricate evolutionary history of the diploid-polyploid complexVeronica subsection Pentasepalae(Plantaginaceae)

[EN]Veronica subsection Pentasepalae is a diploid–polyploid complex of c. 20 species distributed in Eurasia and North Africa, in which species boundaries are difficult to determine. Here, we present the first comprehensive phylogenetic analysis of V. subsection Pentasepalae based on nucleotide sequences [internal transcribed spacer (ITS) and the plastid trnH-psbA and ycf6-psbM spacers] combined with ploidy estimations. Our results support the monophyly of the subsection. Five well-supported clades are recovered in the ITS sequence analyses, corresponding to broad geographical areas. The causes of the extensive incongruence found between the ITS and plastid DNA datasets, namely incomplete lineage sorting and/or hybridization and polyploidization, are discussed. Most of the diploids traditionally recognized based on morphological characters and one tetraploid are each recovered as monophyletic by the ITS sequence analyses. The Balkan species V. kindlii is resurrected. DNA ploidy level for V. teucrioides is reported here for the first time (2x). Diploid populations have been found for V. orbiculata, which was previously thought to be only tetraploid. Past contact in the amphi-Adriatic area between V. orsiniana and V. orbiculata is suggested. Finally, molecular analyses show that diploid V. jacquinii and diploid V. orbiculata are unrelated. This study contributes to our understanding of the evolutionary history of polyploid complexes, especially those in southern Europe, and highlights the importance of using multiple lines of evidence to investigate species boundaries in such actively diversifying groups

DNA extraction from old herbarium material of Veronica subgen. Pseudolysimachium (Plantaginaceae)

Herbarium specimens have become a major source of information in molecular biodiversity research, framing the term "herbarium genomics". However, obtaining good DNA from old herbarium specimens is still a challenge. Currently, DNA extraction methods from old herbarium material often yield highly degraded and fragmented DNA. A number of studies have discussed such methods, especially how to avoid further DNA fragmentation. This study aims to compare different DNA extraction methods applied to old herbarium material from Veronica subg. Pseudolysimachium. One such method is a CTABbased DNA extraction followed by a clean-up with paramagnetic beads that is used in the Jodrell Laboratory, Royal Botanic Gardens Kew, UK. This method was compared to a modified NucleoSpin Plant II protocol, based on silica columns, as used at the Technical University Munich-Freising, which was already successfully used for extracting DNA from a Linnean type specimen. Further tests were conducted on the influence of incubation time on the CTAB DNA extraction protocol with a subsample of specimens. Our preliminary results suggest that CTAB DNA extraction might have some advantages in specific cases but also that silica column-based methods have fewer problems with contamination by polysaccharides and polyphenolic compounds. Regarding the incubation time, we did not observe a clear pattern, but we developed several ideas on how to proceed with tests to find an optimal DNA extraction protocol to deal with highly fragmented DNA. Taking practical considerations into account, the column-based method proves to be preferable, especially when trying to reduce the amount of leaf tissue used, but further modifications of both methods should be explored

Auswirkung der EMV-Anforderungen auf den Netzteilentwurf für Modellbahnsysteme

Klassische Modellbahnsysteme werden mittels eines Streufeldtransformators zur Netztrennung versorgt. Für Systeme mit Gleichspannung wird ein Gleichrichter zwischen dem regelbaren Trafoausgang geschaltet, für Wechselspannungssysteme entfällt dieser. Der Transformator dient gleichzeitig zur Stellung der Ausgangsspannung und damit der Fahrgeschwindigkeit sowie zur Versorgung von weiteren Lasten (Weichenantrieb, Beleuchtung). An den entsprechenden Ausgängen wird die Gleisanlage angeschlossen, auf der eine oder mehrere Lokomotiven durch Kleinmaschinen mit Bürsten angetrieben werden. Die auftretenden EMV-Störungen werden hierbei vom Strom über die Bürsten des Motors, dem Stromfluss innerhalb der Lokomotive über sich drehende Teile des Getriebes oder des Gestänges sowie dem Stromfluss über den Rad-Schiene-Kontakt erzeugt. Der Transformator selbst erzeugt, den Einfluss des Gleichrichters ausgenommen, keine EMV-Störungen. Er dient vielmehr als Filterelement zum Netz hin. Diese Rundfunkstörungen sorgen seit der Existenz des Modellbahnsystems zu Komplikationen mit dem Rundfunk im Frequenzbereich der Mittelwelle, der in Deutschland jedoch an Bedeutung verloren hat. Aus diesem Grund wurde im letzten Jahrhundert eine Messung der Funkstörspannungen am Gleis gegenüber PE mit einem Tastkopf in den EMV-Normen aufgenommen, die immer noch Bestand hat (1). In der Norm ist nicht spezifiziert, an welcher Stelle am Gleis oder auf welchem Leitungsabschnitt die Störspannung erfasst werden muss. Der Messpunkt wird vom jeweiligen Prüfer bestimmt

Is genome downsizing associated with diversification in polyploid lineages of Veronica?

[EN] The study of genome size evolution in a phylogenetic context in related polyploid and diploid lineages can help us to understand the advantages and disadvantages of genome size changes and their effect on diversification. Here, we contribute 199 new DNA sequences and a nearly threefold increase in genome size estimates in polyploid and diploid Veronica (Plantaginaceae) (to 128 species, c. 30% of the genus) to provide a comprehensive baseline to explore the effect of genome size changes. We reconstructed internal transcribed spacer (ITS) and trnL-trnL-trnF phylogenetic trees and performed phylogenetic generalized least squares (PGLS), ancestral character state reconstruction, molecular dating and diversification analyses. Veronica 1C-values range from 0.26 to 3.19 pg. Life history is significantly correlated with 1C-value, whereas ploidy and chromosome number are strongly correlated with both 1C- and 1Cx-values. The estimated ancestral Veronica 1Cx-value is 0.65 pg, with significant genome downsizing in the polyploid Southern Hemisphere subgenus Pseudoveronica and two Northern Hemisphere subgenera, and significant genome upsizing in two diploid subgenera. These genomic downsizing events are accompanied by increased diversification rates, but a ‘core shift’ was only detected in the rate of subgenus Pseudoveronica. Polyploidy is important in the evolution of the genus, and a link between genome downsizing and polyploid diversification and species radiations is hypothesized

Информационная система сравнения программных продуктов в области медицины

Целью данной работы является сравнение медицинских программных продуктов для использования в области медицины. В процессе исследования проводился теоретический анализ, обзор аналогов, проектирование и разработка информационной системы. Среда разработки: "Встроенный язык 1С". Область применения: "Поликлиника №1" г. Юрги Разрабатываемая информационная система должна обеспечивать выполнение следующих функций: 1.Учет информации об экспертах; 2.Учет информации о программном обеспечение (ПО); 3.Сравнение ПО методом комплексной оценки. Проанализированы производственные и вредные факторы. В целом, рабочее место пользователя удовлетворяет стандартам и нормам безопасности.The aim of this work is to compare medical software products for use in the field of medicine. In the course of the research, a theoretical analysis, a review of analogs, design and development of an information system were carried out. Development environment: "Built-in 1C language". Scope: "Polyclinic No. 1" in Yurga. The developed information system must ensure the performance of the following functions: 1. Accounting for information about experts; 2. Accounting for information about software (software); 3. Comparison of software by the method of integrated assessment. The production and harmful factors are analyzed. In general, the user's workplace meets safety standards and regulations

Polyploidy on Islands: Its Emergence and Importance for Diversification.

Whole genome duplication or polyploidy is widespread among floras globally, but traditionally has been thought to have played a minor role in the evolution of island biodiversity, based on the low proportion of polyploid taxa present. We investigate five island systems (Juan Fernández, Galápagos, Canary Islands, Hawaiian Islands, and New Zealand) to test whether polyploidy (i) enhances or hinders diversification on islands and (ii) is an intrinsic feature of a lineage or an attribute that emerges in island environments. These island systems are diverse in their origins, geographic and latitudinal distributions, levels of plant species endemism (37% in the Galapagos to 88% in the Hawaiian Islands), and ploidy levels, and taken together are representative of islands more generally. We compiled data for vascular plants and summarized information for each genus on each island system, including the total number of species (native and endemic), generic endemicity, chromosome numbers, genome size, and ploidy levels. Dated phylogenies were used to infer lineage age, number of colonization events, and change in ploidy level relative to the non-island sister lineage. Using phylogenetic path analysis, we then tested how the diversification of endemic lineages varied with the direct and indirect effects of polyploidy (presence of polyploidy, time on island, polyploidization near colonization, colonizer pool size) and other lineage traits not associated with polyploidy (time on island, colonizer pool size, repeat colonization). Diploid and tetraploid were the most common ploidy levels across all islands, with the highest ploidy levels (>8x) recorded for the Canary Islands (12x) and New Zealand (20x). Overall, we found that endemic diversification of our focal island floras was shaped by polyploidy in many cases and certainly others still to be detected considering the lack of data in many lineages. Polyploid speciation on the islands was enhanced by a larger source of potential congeneric colonists and a change in ploidy level compared to overseas sister taxa

Polyploidy on Islands: Its Emergence and Importance for Diversification.

Whole genome duplication or polyploidy is widespread among floras globally, but traditionally has been thought to have played a minor role in the evolution of island biodiversity, based on the low proportion of polyploid taxa present. We investigate five island systems (Juan Fernández, Galápagos, Canary Islands, Hawaiian Islands, and New Zealand) to test whether polyploidy (i) enhances or hinders diversification on islands and (ii) is an intrinsic feature of a lineage or an attribute that emerges in island environments. These island systems are diverse in their origins, geographic and latitudinal distributions, levels of plant species endemism (37% in the Galapagos to 88% in the Hawaiian Islands), and ploidy levels, and taken together are representative of islands more generally. We compiled data for vascular plants and summarized information for each genus on each island system, including the total number of species (native and endemic), generic endemicity, chromosome numbers, genome size, and ploidy levels. Dated phylogenies were used to infer lineage age, number of colonization events, and change in ploidy level relative to the non-island sister lineage. Using phylogenetic path analysis, we then tested how the diversification of endemic lineages varied with the direct and indirect effects of polyploidy (presence of polyploidy, time on island, polyploidization near colonization, colonizer pool size) and other lineage traits not associated with polyploidy (time on island, colonizer pool size, repeat colonization). Diploid and tetraploid were the most common ploidy levels across all islands, with the highest ploidy levels (>8x) recorded for the Canary Islands (12x) and New Zealand (20x). Overall, we found that endemic diversification of our focal island floras was shaped by polyploidy in many cases and certainly others still to be detected considering the lack of data in many lineages. Polyploid speciation on the islands was enhanced by a larger source of potential congeneric colonists and a change in ploidy level compared to overseas sister taxa

Two-phase reservoir: development of a transient thermo-hydraulic model based on bond graph approach with experimental validation

The main purpose of the project FUI THERMOFLUID is to study the feasibility of a new electronic cooling system embedded on flying objects (missile, satellite, and airplane). The technology chosen consists of a pumped two-phase flow cooling loop (PTPFL). It is an innovative technology with a transport capacity of the thermal power up to 10 MW.m, exceeding in this way the performance of all other technologies. A PTPFL is a cooling loop based on the exploitation of the latent heat properties of the fluid trapped inside the loop, and moved by a pump. The components constituting a PTPFL are: a two-phase reservoir (TP-R), a mini- channels evaporator, a brazed plate condenser, a pump and pipes. The global research work is devoted to propose a dynamic model and experimental validation of the PTPFL. The present article is exclusively dedicated to the TP-R two-phase reservoir (TP-R). Indeed this element plays a key role in the functioning of PTPFL. Historically, the TP-R did not equip the first cooling loop. However, due to its advantages its introduction was essential. The developed dynamic model will be used in another work to predict the thermal hydraulic efficiency of the PTPFL from its mechanical and fluidic parameters, to conduct the study of transitional regimes and instability problems, and provides an original tool dedicated to design the TP-R in function of the thermal power levels to be evacuated and the selected refrigerant. The bond graph methodology is adopted for modeling works because of its energetic approach and multi physics character of the studied system.FUI Thermofluid-R

Environmental differences are correlated with the distribution pattern of cytotypes in Veronica subsection Pentasepalae at a broad scale

[EN] Background and Aims: The distribution of cytotypes and its potential correlation with environmental variables represent a cornerstone to understanding the origin and maintenance of polyploid lineages. Although many studies have addressed this question in single species at a regional scale, only a few have attempted to decipher this enigma in groups of closely related species at a broad intercontinental geographical scale. Here, we consider approx. 20 species of a diploid–polyploid complex (Veronica subsect. Pentasepalae) of recent and rapid diversification represented in Europe and North Africa to study the frequency and distribution of cytotypes and their relationship to environmental variables. Methods: A total of 680 individuals (207 populations) were sampled. Ploidy levels were determined using flow cytometry. Ecological differentiation among cytotypes was tested using climatic and environmental variables related to temperature, precipitation, vegetation and biogeographical region, among others, and by performing univariate and multivariate (constrained principal coordinates analysis) analyses. Key Results: Four ploidy levels (2x, 4x, 6x and 8x) were found and genome downsizing was observed to occur within the group. Plants of different ploidy level are ecologically differentiated, with hexaploids and octoploids occurring in wetter and colder habitats with a higher seasonality than diploids. A south to north distribution pattern was found, with diploids occupying southern refugial areas and octoploids being more frequent in northern regions of Europe above the permafrost boundary. Conclusions: The distribution of cytotypes can be explained by ecological differentiation, the geographical position of refuge areas during the Quaternary climatic oscillations as well as by ice and permafrost retreat patterns. The Balkan Peninsula constitutes the most important contact zone between cytotypes. This work provides the first comprehensive ploidy screening within V. subsect. Pentasepalae at a broad scale and indicates that polyploidy and genome downsizing might have contributed to the colonization of new habitats in a recently diverged polyploid complex.Spanish Ministerio de Economía y Competitividad [projects CGL2009-07555 and CGL2012-32574]; the Spanish Ministerio de Ciencia e Innovación [PhD grants AP2008-03434 to B.R.A. and AP2010-2968 to N.L.G.]; and the University of Salamanca [PhD grant to N.P.G. co-financed by Banco Santander]