Bekämpfung der Gloeosporium-Fruchtfäule an ökologisch produzierten Äpfeln – Optimierung einer Heißwassertauchanlage

Die Langzeitlagerung von Äpfeln aus Ökologischem Landbau ist oftmals problematisch, da Lagerspritzungen mit wirksamen Fungiziden vor der Ernte nicht zulässig sind und sich daher Pilzkrankheiten, wie die gefährliche Gloeosporium-Fäule, im Lager unerkannt entwickeln können. Die Krankheit verursacht Lagerungsverluste von bis zu 50 %, selbst bei der Lagerung unter kontrollierter Atmosphäre (CA-Lagerung). Durch die Kombination einer Heißwasserbehandlung (53 °C, 2 Minuten) und einer anschließenden Lagerung unter kontrollierter Atmosphäre kann die Gloeosporium-Fäule auf ca. 3 % im Vergleich zu 41 % bei ungetauchten Äpfeln reduziert werden. Noch deutlicher fällt das Ergebnis für unter Normalluft bei 1 °C gelagerten Äpfeln aus. Hier konnte durch eine Heißwasserbehandlung die Gloeosporium-Fruchtfäule auf 17 % reduziert werden im Vergleich zu 94 % bei ungetauchten Äpfeln des Ökologischen Landbaus. Die Heißwasserbehandlung zur Reduzierung des Lagerpilzes kann mit einer an der Bundesforschungsanstalt für Ernährung entwickelten, einfachen Anlage für Äpfel in 20 kg Obstkisten, durchgeführt werden. Durch die verbesserte Isolierung der vorhandenen Pilotanlage und Erhöhung der Heizleistung von 9 auf 15 kW konnte die Aufheizdauer von 4h 15 min auf 2h 45 min verkürzt werden. Des weiteren wurde der Wärmeübergang durch eine verbesserte Wasserumwälzung und dadurch optimierte Durchströmung der Obstkisten erhöht. Dazu wurde eine leistungsfähigere Edelstahl-Kreiselpumpe (30 m³/h) eingebaut. Zusätzlich wurde die Pilotanlage durch den Anbau eines Förderbandes und eines Hubtisches für den (halb-)kontinuierlichen Betrieb ausgebaut. Damit steht zu Projektende eine praxistaugliche Anlage zur Behandlung von ökologisch erzeugtem Obst zur Verfügung. In Zukunft können mit dieser Anlage auch andere Obst- und Gemüsesorten in unterschiedlich großen Verpackungseinheiten (Kisten) behandelt werden und so für jedes Produkt optimale Prozeßparameter ermittelt werden

Optical brain imaging using a semi-transparent organic light-emitting diode

We report optical brain imaging using a semi-transparent organic light-emitting diode (OLED) based on the orange light-emitting polymer (LEP) Livilux PDO-124. The OLED serves as a compact, extended light source which is capable of uniformly illuminating the cortical surface when placed across a burr hole in the skull. Since all layers of the OLED are substantially transparent to photons with energies below the optical gap of the LEP, light emitted or reflected by the cortical surface may be efficiently transmitted through the OLED and into the objective lens of a low magnification microscope ('macroscope'). The OLED may be placed close to the cortical surface, providing efficient coupling of incident light into the brain cavity; furthermore, the macroscope may be placed close to the upper surface of the OLED, enabling efficient collection of reflected/emitted light from the cortical surface. Hence the use of a semi-transparent OLED simplifies the optical setup, while at the same time maintaining high sensitivity. The OLED is applied here to one of the most demanding forms of optical brain imaging, namely extrinsic optical imaging involving a voltage sensitive dye (VSD). Specifically, we carry out functional imaging of the primary visual cortex (V1) of a rat, using the voltage sensitive dye RH-1691 as a reporter. Imaging through the OLED light-source, we are able to resolve small (~ 0.1 %) changes in the fluorescence intensity of the dye due to changes in the neuronal membrane potential following a visual stimulus. Results are obtained on a single trial basis -- i.e. without averaging over multiple measurements -- with a time-resolution of ten milliseconds

Disaccahrides-based cryo-formulant effect on modulating phospho/mitochondrial lipids and biological profiles of human leukaemia cells

BACKGROUND/AIMS: The use of novel cryo-additive agents to increase cell viability post-cryopreservation is paramount to improve future cell based-therapy treatments. We aimed to establish the Human Leukemia (HL-60) cells lipidomic and biological patterns when cryo-preserved in DMSO alone and with 300 µM Nigerose (Nig), 200 µM Salidroside (Sal) or a combination of Nig (150 µM) and Sal (100 µM). METHODS: HL-60 cells were pre-incubated with Nig/Sal prior, during and post cryopreservation, and subjected to global lipidomic analysis. Malondialdeyhde (MDA), released lactate dehydrogenase (LDH) and reactive oxygen scavenger (ROS) measurements were also carried out to evaluate levels of lipid peroxidation and cytotoxicity. RESULTS: Cryopreserving HL-60 cells in DMSO with Nig and Sal provided optimal protection against unsaturated fatty acid oxidation. Post-thaw, cellular phospholipids and mitochondrial cardiolipins were increased by Nig/Sal as the ratio of unsaturated to saturated fatty acids 2.08 +/- 0.03 and 0.95 +/- 0.09 folds respectively in comparison to cells cryopreserved in DMSO alone (0.49 +/- 0.05 and 0.86 +/- 0.10 folds). HL-60 lipid peroxidation levels in the presence of DMSO + Nig and Sal combined were significantly reduced relative to pre-cryopreservation levels (10.91 +/- 2.13 nmole) compared to DMSO (17.1 +/- 3.96 nmole). DMSO + Nig/Sal combined also significantly reduced cell cytotoxicity post-thaw (0.0128 +/- 0.00182 mU/mL) in comparison to DMSO (0.0164 +/- 0.00126 mU/mL). The combination of Nig/Sal also reduced significantly ROS levels to the levels of prior cryopreservation of HL-60. CONCLUSION: Overall, the establishment of the cryopreserved HL-60 cells lipidomic and the corresponding biological profiles showed an improved cryo-formulation in the presence of DMSO with the Nig/Sal combination by protecting the, mitochondrial inner membrane, unsaturated fatty acid components (i. e. Cardiolipins) and total phospholipids

Sub-millisecond control of neuronal firing by organic light-emitting diodes

Optogenetics combines optics and genetics to enable minimally invasive cell-type-specific stimulation in living tissue. For the purposes of bio-implantation, there is a need to develop soft, flexible, transparent and highly biocompatible light sources. Organic semiconducting materials have key advantages over their inorganic counterparts, including low Young's moduli, high strain resistances, and wide color tunability. However, until now it has been unclear whether organic light emitting diodes (OLEDs) are capable of providing sufficient optical power for successful neuronal stimulation, while still remaining within a biologically acceptable temperature range. Here we investigate the use of blue polyfluorene- and orange poly(p-phenylenevinylene)-based OLEDs as stimuli for blue-light-activated Sustained Step Function Opsin (SFFO) and red-light-activated ChrimsonR opsin, respectively. We show that, when biased using high frequency (multi-kHz) drive schemes, the OLEDs permit safe and controlled photostimulation of opsin-expressing neurons and were able to control neuronal firing with high temporal-resolution at operating temperatures lower than previously demonstrated

Tracking the ultraviolet-induced photochemistry of thiophenone during and after ultrafast ring opening

Photoinduced isomerization reactions lie at the heart of many chemical processes in nature. The mechanisms of such reactions are determined by a delicate interplay of coupled electronic and nuclear dynamics occurring on the femtosecond scale, followed by the slower redistribution of energy into different vibrational degrees of freedom. Here we apply time-resolved photoelectron spectroscopy with a seeded extreme ultraviolet free-electron laser to trace the ultrafast ring opening of gas-phase thiophenone molecules following ultraviolet photoexcitation. When combined with ab initio electronic structure and molecular dynamics calculations of the excited- and ground-state molecules, the results provide insights into both the electronic and nuclear dynamics of this fundamental class of reactions. The initial ring opening and non-adiabatic coupling to the electronic ground state are shown to be driven by ballistic S–C bond extension and to be complete within 350 fs. Theory and experiment also enable visualization of the rich ground-state dynamics that involve the formation of, and interconversion between, ring-opened isomers and the cyclic structure, as well as fragmentation over much longer timescales

Materials and Molecular Modelling at the Exascale

Progression of computational resources towards exascale computing makes possible simulations of unprecedented accuracy and complexity in the fields of materials and molecular modelling (MMM), allowing high fidelity in silico experiments on complex materials of real technological interest. However, this presents demanding challenges for the software used, especially the exploitation of the huge degree of parallelism available on exascale hardware, and the associated problems of developing effective workflows and data management on such platforms. As part of the UKs ExCALIBUR exascale computing initiative, the UK-led MMM Design and Development Working Group has worked with the broad MMM community to identify a set of high priority application case studies which will drive future exascale software developments. We present an overview of these case studies, categorized by the methodological challenges which will be required to realize them on exascale platforms, and discuss the exascale requirements, software challenges and impact of each application area

Enhanced ion-selective membrane sensors based on a novel electroacoustic measurement approach

this work investigates the mechanical and dielectric properties of an ion-selective membrane based on PDMS:PEG:valinomycin, with a view to creating practical geometries for high performance ion sensing in a variety of realworld settings including healthcare, food industry and agriculture. We focus effort on measuring physical changes in the membrane that can be detected with simple sensors. First a dynamic mechanical analyser instrument was used to determine the effect of potassium ions on the real and imaginary bending storage modulus, loss tangent, glass transition temperature, temperature coefficient of millimeter sized PDMS samples. Second, a microwave dielectric analyser with a coaxial probe fixture was applied to the same sample to isolate dielectric shifts associated with ion uptake, namely the real and imaginary permittivities. These perturbation measurements performed for PDMS, PDMS:PEG and PDMS:PEG:V samples, provide strong evidence that alternatives to traditional electrochemical sensing devices can easily be constructed. Thus a plethora of new acoustic and capacitive sensing geometries arise. Thus there is the opportunity to integrate membranes into quartz crystal microbalance, surface acoustic wave and single-sided capacitance sensors. Some suggestions on suitable dimensions, aspect ratios, operating frequencies are provided