Epidemiology and antifungal resistance in invasive candidiasis

The epidemiology of Candida infections has changed over the last two decades: The number of patients suffering from such infections has increased dramatically and the Candida species involved have become more numerous as Candida albicans is replaced as an infecting agent by various non-C. albicans species (NAC). At the same time, additional antifungal agents have become available. The different Candida species may vary in their susceptibility for these various antifungals. This draws more attention to in vitro susceptibility testing. Unfortunately, several different test methods exist that may deliver different results. Moreover, clinical breakpoints (CBP) that classify test results into susceptible, intermediate and resistant are controver- sial between CLSI and EUCAST. Therefore, clinicians should be aware that interpretations may vary with the test system being followed by the microbiological laboratory. Thus, knowledge of actual MIC values and pharmacokinetic properties of individual antifungal agents is important in delivering appropriate therapy to patient

Wettability of natural root mucilage studied by atomic force microscopy and contact angle: Links between nanoscale and macroscale surface properties

Organic coatings are considered as main cause of soil water repellency (SWR). This phenomenon plays a crucial role in the rhizosphere, at the interface of plant water uptake and soil hydraulics. Still, there is little knowledge about the nanoscale properties of natural soil compounds such as root-mucilage and its mechanistic effect on wettability. In this study, dried films of pure and diluted natural root-mucilage from Sorghum (Sorghum sp., moench) on glass substrates were studied in order to explore experimental and evaluation methods that allow to link between macroscopic wettability and nano-/microscopic surface properties in this model soil system. SWR was assessed by optical contact angle (CA) measurements. The nanostructure of topography and adhesion forces of the mucilage surfaces was characterized by atomic force microscopy (AFM) measurements in ambient air, using PeakForce Quantitative Nanomechanical Mapping (PFQNM). Undiluted mucilage formed hydrophobic films on the substrate with CA > 90° and rather homogeneous nanostructure whereas the contact angles of diluted samples were < 90°. AFM height and adhesion images displayed incomplete mucilage surface coverage for diluted samples. Hole-like structures in the film frequently exhibited increased adhesion forces. The spatial analysis of the AFM data via variograms enabled a numerical description of such ‘adhesion holes’. The use of geostatistical approaches in AFM studies of the complex surface structure of soil compounds was considered meaningful in view of the need of comprehensive analysis of large AFM image data sets that exceed the capability of comparative visual inspection. Furthermore, force curves measured with the AFM showed increased break-free distances and pull-off forces inside the observed ‘adhesion holes’, indicating enhanced capillary forces due to adsorbed water films at hydrophilic domains for ambient RH (40 ± 2 %). This offers the possibility of mapping the nanostructure of water layers on soil surfaces and assessing the consequences for wettability. The collected information on macroscopic wetting properties, nanoscale roughness and adhesion structure of the investigated surfaces in this study are discussed in view of the applicability of the mechanistic wetting models given by Wenzel and Cassie-Baxter

Multi-site H-bridge breathers in a DNA--shaped double strand

We investigate the formation process of nonlinear vibrational modes representing broad H-bridge multi--site breathers in a DNA--shaped double strand. Within a network model of the double helix we take individual motions of the bases within the base pair plane into account. The resulting H-bridge deformations may be asymmetric with respect to the helix axis. Furthermore the covalent bonds may be deformed distinctly in the two backbone strands. Unlike other authors that add different extra terms we limit the interaction to the hydrogen bonds within each base pair and the covalent bonds along each strand. In this way we intend to make apparent the effect of the characteristic helicoidal structure of DNA. We study the energy exchange processes related with the relaxation dynamics from a non-equilibrium conformation. It is demonstrated that the twist-opening relaxation dynamics of a radially distorted double helix attains an equilibrium regime characterized by a multi-site H-bridge breather.Comment: 27 pages and 10 figure

Short-term soil response under plastic mulching in strawberry cultivation

Plastic mulches (PM) are known for increasing soil temperature and retaining soil moisture, suppressing weeds and avoiding ground contact of on-soil growing products. Thus, the use of PM in agriculture has been significantly increased in the last years, with important economic benefits for the farmers. Most studies dealing with PM emphasize the positive effects of this management, yet recent reports have shown that the use of PM is linked to a decrease of SOM content, soil erosion, soil contamination with plastic residues and in some cases to a high mycotoxin production by soil fungi. This questions the sustainability of the intensive use of PM in agriculture. The aim of this study was to assess the short-term modification of soil physicochemical and microbial parameters under PM, compared to no-mulch (NM). The experiment was conducted in a 2016-planted strawberry field. For each management (PM vs. NM) five plots were selected. Cultivation of strawberry in both PM and NM was done in a ridge-furrow system with subsurface irrigation. Samples were collected prior to the planting (T0) and successively at two (T1) and four months (T2) after planting. Different depths were sampled in the ridges (0-10, 10-30 and 30-60 cm) and in the furrows (0-10 and 10-40 cm). The analysis of the quantity and quality of soil organic matter is ongoing and comprised soil physicochemical analysis: pH, electrical conductivity, water content, bulk density and stability, organic C and N and density fractionation. Moreover, soil microbiology was studied via soil microbial carbon and mycotoxin occurrence as indicator of fungal stress. Additionally, temperature, humidity and pH of soil were daily recorded using an in-field installed measuring station. The continuously recorded environmental data showed differences in the temperature patterns between PM and NM, with highest average temperature under plastic. As well, pH and humidity data indicated differences between the treatments

Combined proton NMR wideline and NMR relaxometry to study SOM-water interactions of cation-treated soils

Focusing on the idea that multivalent cations affect SOM matrix and surface, we treated peat and soil samples by solutions of NaCl, CaCl2 or AlCl3. Water binding was characterized with low field 1H-NMR-relaxometry (20 MHz) and 1H wideline NMR spectroscopy (400 MHz) and compared to contact angles. From 1H wideline, we distinguished mobile water and water involved in water molecule bridges (WaMB). Large part of cation bridges (CaB) between SOM functional groups are associated with WaMB. Unexpectedly, 1H NMRrelaxometry relaxation rates suggest that cross-linking in the Al-containing peat is not stronger than that by Ca. The relation between percentage of mobile water and WaMB water in the context of wettability and 1H NMR relaxation times confirms that wettability controls the water film surrounding soil particles. Wettability is controlled by WaMB-CaB associations fixing hydrophilic functional groups in the SOM interior. This can lead to severe water repellency. Wettability decreases with increasing involvement of functional groups in CaB-WaMB associations. The results demonstrate the relevance of CaB and WaMB for the dynamics of biogeochemical and hydrological processes under field conditions, as only a few percent of organic matter can affect the physical, chemical, and biological functioning of the entire 3-phase ecosystem

Stretching and relaxation dynamics in double stranded DNA

We study numerically the mechanical stability and elasticity properties of duplex DNA molecules within the frame of a network model incorporating microscopic degrees of freedom related with the arrangement of the base pairs. We pay special attention to the opening-closing dynamics of double-stranded DNA molecules which are forced into non-equilibrium conformations. Mechanical stress imposed at one terminal end of the DNA molecule brings it into a partially opened configuration. We examine the subsequent relaxation dynamics connected with energy exchange processes between the various degrees of freedom and structural rearrangements leading to complete recombination to the double-stranded conformation. The similarities and differences between the relaxation dynamics for a planar ladder-like DNA molecule and a twisted one are discussed in detail. In this way we show that the attainment of a quasi-equilibrium regime proceeds faster in the case of the twisted DNA form than for its thus less flexible ladder counterpart. Furthermore we find that the velocity of the complete recombination of the DNA molecule is lower than the velocity imposed by the forcing unit which is in compliance with the experimental observations for the opening-closing cycle of DNA molecules.Comment: 21 pages, 9 figure

Shift of microbial communities and reduced enzymatic activity in soil under plastic mulching system in strawberry cultivation

The use of plastic mulching (PM) in agriculture has strongly increased in the last years. Improved water saving and higher soil temperature are some advantages of this management. Yet, an intensive use of PM has been recently linked to negative effects on soil quality. The aim of this study is thus to assess the effects of long-term plastic mulching (PM) on soil microbial indicators. PM was compared with the use of wheat straw mulching (SM), an also widely used mulch material. Samples were collected at two depths (0-5 and 5-10 cm) from strawberry fields, after 4-year management. Cultivation in PM and SM was done in a ridge-furrow system with subsurface irrigation. Soil characterization comprised soil texture and aggregate stability, soil organic carbon, pH and water content. Soil microbial analysis included: Soil microbial biomass (Cmic), a fraction of soil cultivable fungi (CFU values), soil bacteria (16S rRNA), denitrifying community (nirK, nirS, narG, napA genes), soil enzyme activity (C-Chitinase, P-Phosphatase and N Leucine-aminopeptidase), deoxynivalenol (DON) content and Cmic:Corg ratio. Positive effects on soil physicochemical properties were observed under PM as compared to SM, reflected by a higher soil carbon content and better aggregate stability (p>0.05). Yet, soil microbial analysis revealed some differences between managements. Cmic values were comparable in both systems, showing no differences in soil microbial biomass. In the same way, the analysis of functional genes of the N cycle and the activity of the enzymes P-Phosphatase and N Leucine-aminopeptidase was not affected by the mulching treatment. But, the abundance of bacteria (18%) and a fraction of soil cultivable fungi were reduced by respectively 18 and 62% under PM. Since the Cmic values remained similar between treatments, this accounts for a shift of microbial communities under PM. Additionally, C-Chitinase activity declined under PM. Interestingly, this enzyme correlated positively with CFU values (r=0.781, p=0.001), suggesting that a reduction of the activity is a consequence of the reduction of the fungal biomass. Additionally, a higher deoxynivalenol concentration (2.2 ± 2.4 µg kg-1) and a reduced Cmic:Corg ratio (1.3±0.3%) were observed under PM, indicative of less appropriate soil conditions after long-term PM management

Global Optimization by Energy Landscape Paving

We introduce a novel heuristic global optimization method, energy landscape paving (ELP), which combines core ideas from energy surface deformation and tabu search. In appropriate limits, ELP reduces to existing techniques. The approach is very general and flexible and is illustrated here on two protein folding problems. For these examples, the technique gives faster convergence to the global minimum than previous approaches.Comment: to appear in Phys. Rev. Lett. (2002

Analysis of Interactions and Support of Decision Making for the Implementation of Manufacturing Systems 4.0 Methods

For the successful implementation of Manufacturing Systems 4.0 (MS4.0) in medium-sized companies, a structured introduction process is required. Main objective of this process is the analysis and evaluation of MS4.0 methods in order to select those that suit best for each company. The foundation of this process is a structure model to classify and describe MS4.0 methods. A subsequent analysis of interactions among the methods supports the identification and evaluation of effective implementation strategies. Thereby, a model based on system dynamics is applied. Based on the results, the methods are strategically and financially evaluated to select the MS4.0 methods suited for implementation. Finally, a method roadmap can be derived to support management for the strategic decisions in regards of MS4.0 methods

Einfluss von Bewässerung und Düngung auf die organische Bodensubstanz in extensiv genutzten Heuwiesen - Thermische Eigenschaften und Evolved Gasanalyse

Wiesen beherbergen etwa 40 % der in Deutschland geschützten Arten. Neben ihrer Funktion zur Erhaltung der Biodiversität dienen sie als Überschwemmungsflächen dem Hochwasserschutz und sorgen für eine Filterung des Grund- und Oberflächenwassers. Aufgrund dieser wichtigen Funktionen wurden in der Vergangenheit viele Untersuchungen gemacht, wie sich unterschiedliche landwirtschaftliche Bewirtschaftungsformen auf die Biodiversität von Wiesen auswirken. Um diese Prozesse besser zu verstehen ist es nötig, auch die unterirdisch ablaufenden biogeochemischen Prozesse zu berücksichtigen. Neben Bodenflora und –fauna spielen dabei auch abiotische Bodeneigenschaften wie z.B. Nährstoffgehalt und –verfügbarkeit oder Wasserhaltekapazität eine entscheidende Rolle. Der Nährstoff- und Wasserhaushalt eines Bodens hängt wiederum stark vom Gehalt und der Qualität der organische Bodensubstanz ab. Um die Kopplung von unterirdischen biogeochemischen Prozessen mit der oberirdischen Pflanzendiversität besser zu verstehen, haben wir in einem ersten Schritt die Auswirkung von Bewässerung und Düngung auf ausgewählte Eigenschaften der organischen Bodensubstanz mithilfe von Thermogravimetrie (TGA) gekoppelt mit Differential Scanning Calorimetry (DSC) und Evolved Gasanalyse mit Massenspektrometrie (EGA-MS) untersucht. Hierzu wurden 12 extensiv genutzte Heuwiesen, die sogenannten „Wässerwiesen“, entlang der Queich bei Landau (Rheinland-Pfalz) beprobt. Diese Wiesen wurden seit dem Mittelalter traditionell nach einem festgelegten Bewässerungskalender zwei bis dreimal im Jahr für ein bis drei Tage durch Überflutung mit dem Wasser der Queich bewässert. Auf einigen dieser Wiesen wurde diese Form der Bewässerung seit den 50iger Jahren eingestellt. Dadurch ergab sich die einmalige Möglichkeit vergleichbare Wiesen mit und seit über 50 Jahren ohne Überflutungsbewässerung sowie mit und ohne anorganische Düngung zu untersuchen. Im vorliegenden Beitrag werden die Ergebnisse dieser Studie vorgestellt und die Möglichkeiten und Grenzen thermischer Methoden zur Charakterisierung von organischer Bodensubstanz diskutiert