914 research outputs found

    Effect of lysophosphatidylcholine on the surface hydration of phospholipid vesicles

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    AbstractThe interfacial properties of the negatively charged dimyristoyl-phosphatidylglycerol (DMPG) and the zwitterionic dimyristoyl-phosphatidylcholine (DMPC) vesicles mixed with the fusion inhibitor lysomyristoylphosphatidylcholine (LMPC) are investigated by electron paramagnetic resonance (EPR). At 35 °C, addition of 20 mol% of LMPC to the DMPG vesicles increases the effective concentration of water in the interfacial layer of DMPG vesicles from 19.3 M to 27.7 M, whereas in the case of mixed DMPC-LMPC vesicle the effective water concentration in the interfacial layer of DMPC vesicles only changes from 15.1 M to 18.4 M. The hydrogen bonding structure in both mixed DMPG-LMPC and mixed DMPC-LMPC vesicles becomes stronger with an increasing fraction of LMPC in the vesicles. The average area per phospholipid decreases in mixed DMPC-LMPC vesicles, while it increases in mixed DMPG-LMPC vesicles as the proportion of LMPC in the vesicle increases. The inhibitory nature of LMPC in both vesicle and biological fusion comes from the increase in surface hydration, as well as from the dynamic cone shape of LMPC in the phospholipid bilayer

    A Three-phase Digital Current Controller with Improved Performance Indices

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    Performance of conventional digital current controllers is constrained by transport delays within the feedback acquisition chain, as well as by delays inherent to the pulse width modulation. In this paper, we introduce a novel current controller which provides a very high closed-loop bandwidth, improves the robustness and disturbance rejection, and eliminates the noise and sampling errors in the feedback path. In order to achieve these goals, we suppress the transport delays by introducing an improved execution schedule of the control interrupt and by inserting a cascaded multiplier of differential character. With the novel gain setting rule, the closed loop bandwidth reaches 17% of the sampling frequency, disturbance rejection capability is doubled, the step response has a negligible overshoot, and the robustness is characterized by the vector margin of 0.65. Experimental verification is performed using an experimental setup with a three-phase inverter, digital controller, and a permanent magnet synchronous motor

    Effects of Phytogenic Feed Additive and Enzyme on Growth Performance of Broilers Fed Diets with Reduced Energy Concentrations

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    The effects of dietary supplementation with phytogenic feed additives (PFA) and enzyme (E) on performance parameters were investigated using Ross 308 as hatched broilers fed standard diets or diets with reduced energy concentrations. Birds were assigned to 5 treatments with 5 replications each and fed either a standard basal diet or a re-formulated basal diet with reduced energy concentrations. Reduction was made according to enzyme matrix (Ronozyme WX, DSM). Treatments were: (1) Standard diet; (2) Negative control (NC) – 4% reduction in ME (3) NC + E; (4) NC + PFA (5) NC + E + PFA. Body weight and feed consumption were recorded weekly. Mortality was recorded on daily basis. Foot pad lesions were scored at day 35 using scale from 0 (no lesion) to 2 (lesion extending through skin). The results showed that birds fed Negative control diets had a significantly lower body weights (P0.05). Mortality and FCR did not differ significantly between treatments. Average foot pad lesion score was the highest in Negative control (1.05) and the lowest in NC+E (0.55). In conclusion, re-formulation of diets for 4% energy reduction decreased broiler growth rate. Supplementation of diets with PFA improved live weight especially in combination with enzyme, hence confirming a growth-promoting effect of both phytogenics and enzymes in broilers

    Status of a DEPFET pixel system for the ILC vertex detector

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    We have developed a prototype system for the ILC vertex detector based on DEPFET pixels. The system operates a 128x64 matrix (with ~35x25 square micron large pixels) and uses two dedicated microchips, the SWITCHER II chip for matrix steering and the CURO II chip for readout. The system development has been driven by the final ILC requirements which above all demand a detector thinned to 50 micron and a row wise read out with line rates of 20MHz and more. The targeted noise performance for the DEPFET technology is in the range of ENC=100 e-. The functionality of the system has been demonstrated using different radioactive sources in an energy range from 6 to 40keV. In recent test beam experiments using 6GeV electrons, a signal-to-noise ratio of S/N~120 has been achieved with present sensors being 450 micron thick. For improved DEPFET systems using 50 micron thin sensors in future, a signal-to-noise of 40 is expected.Comment: Invited poster at the International Symposium on the Development of Detectors for Particle, AstroParticle and Synchrotron Radiation Experiments, Stanford CA (SNIC06) 6 pages, 12 eps figure

    Effect of Litter Treatment on the Occurrence of Foot Pad Lesions

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    Pododermatitis (foot pad lesions) is one of the main welfare problems in modern broiler production in countries with developed poultry farming. Factors contributing to the occurrence of these lesions are nutrition, stocking density and material used for litter. There are a number of different procedures that can be applied in order to prevent and reduce the number of lesions with the most pronounced defects. The experiment was conducted on broiler chickens grown in 10 buildings of 240 m2 each. The stocking density was 35 kg/m2. The experiment was set up in five treatments with two replicates. Treatment one (T1) - control with a straw litter, treatment two (T2) - litter treated with microbial preparation Micropan®, treatment three (T3) – litter with addition of lignin, treatment four (T4) – litter with addition of lignin and Micropan® and treatment five (T5) - chopped straw without supplements. At the end of the experiment, on day 42 the intensity of the lesions was scored on the slaughter line. The presence of lesions was scored using scale from 0 (no lesions) to 3 (plantar pads with more than 50% damage). Based on the results of the trial it can be concluded that litter has a significant impact on the presence and the degree of foot pad lesions. The lowest score of foot pad lesions was observed in the treatment T5 (chopped straw). Different treatments of litters may also contribute to the solution of the problem of pododermatitis since the results in all treated groups (T2, T3, T4 and T5) were better when compared to the control

    Analysis of 19 Minerals and Cortisol in Red Deer Hair in Two Different Areas of the Stelvio National Park: A Preliminary Study

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    The aim of the study was to perform an investigation on the concentration of 19 minerals and cortisol in red deer (Cervuselaphus) hair, a matrix that is easy to collect with non-invasive and painless sampling, able to represent an integrative values of long-term substance concentrations, and able to give useful information, also when performed on dead animals, given its extreme stability over time. In the study thirty-five animals were included, coming from two different sides of a valley in the Stelvio National Park, where official water analysis had pointed out elevated concentrations of As in one of the two orographic sides. Hair cortisol concentrations were measured using a RIA(Radio Immuno Assay), while minerals were detected using ICP-MS (Inductively Coupled Plasma- Mass Spectrometry). Results showed a negative relationship between cortisol and some mineral concentrations (Li, Co, As, Cd, Cr and Tl) and significant differences in some mineral concentrations between park areas (Al, Co, Cu, Cd and Ni). As, Cr and cortisol differences approached statistical significance. This preliminary study represents a step forward in the study of wildlife allostatic load and a valid method for applications in wildlife management programs, in environmental studies and in public health programs

    The New Generation of the KIT 3D USCT

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    The first clinical studies with our current prototype, 3D USCT II, enabled us to identify the necessary improvements for transition of our method to clinical practice. The main goals are to improve the contrast of reflection and transmission tomography, and to optimize the coverage of the imaged breast by a new geometry of the transducer distribution. Furthermore, for cost-effective industrial mass production, a self-calibration method allows us to relax the precision of the positioning of the transducers to 0.1 mm. The readout of the transducer arrays is now carried out by an ASIC, developed for a more cost-effective design. The coupling of the measuring device to the patient was optimized to cover the full size of the breast up to the pectoral muscles. Finally, the data acquisition and readout time were reduced to 1.5 minutes each by new micro-TCA electronics and larger FPGAs

    Determination of fatty acids profile in original brown cows dairy products and relationship with alpine pasture farming system

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    This study aimed to evaluate the relationships between fatty acids and the pattern that most contributes to discriminate between two farming systems, in which the main difference was the practice, or not, of alpine summer-grazing. Milk and cheese were sampled every month in two farms of Original Brown cows identical under geographical location and management during no grazing season point of view in the 2018 season. Fatty acids concentrations were determined by gas chromatography. The principal component analysis extracted three components (PCs). Mammary gland de novo synthetized fatty acids (C14:0, C14:1 n9, and C16:0) and saturated and monosaturated C18 fatty acids (C18:0, C18:1 n9c) were inversely associated in the PC1; PC2 included polyunsaturated C18 fatty acids (C18:2 n6c, C18:3 n3) and C15:0 while conjugated linoleic acid (CLA n9c, n11t) and fatty acids containing 20 or more carbon atoms (C21:0, C20:5 n3) were associated in the PC3. The processes of rumen fermentation and de novo synthesis in mammary gland that are, in turn, influenced by diet, could explain the relationships between fatty acids within each PC. The discriminant analyses showed that the PC2 included the fatty acids profile that best discriminated between the two farming systems, followed by PC3 and, lastly, PC1. This model, if validated, could be an important tool to the dairy industry

    Transceiver ASIC in HVCMOS Technology for 3D Ultrasound Computer Tomography

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    Abstract3D Ultrasound Computer Tomography (3D USCT) is an imaging method for the early de-tection of breast cancer. It provides three-dimensional multimodal images of the breast. Thenew 3D USCT device developed currently at Karlsruhe Institute of Technology containsmore than two thousand ultrasound transducers placed in a water-filled aperture where thepatient submerges one breast. The ultrasound transducers are grouped as transducer arraysystems (TAS) of 18 receiver (RX) and transmitter (TX) elements. The transducer front-end electronics contain high-voltage (HV) and low-voltage (LV) amplifiers and switcheswhich are implemented as an application-specific integrated circuit (ASIC). This contribu-tion presents a patented mixed signal, multichannel, transceiver ASIC developed in a com-mercial 350 nm high-voltage CMOS (HV-CMOS) process. The HV-CMOS process provideslow-voltage and high-voltage transistors that can be combined on the same substrate. TheHV transistors can sustain voltages up to 120 V

    Optimum spectral window for imaging of art with optical coherence tomography

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    Optical Coherence Tomography (OCT) has been shown to have potential for important applications in the field of art conservation and archaeology due to its ability to image subsurface microstructures non-invasively. However, its depth of penetration in painted objects is limited due to the strong scattering properties of artists’ paints. VIS-NIR (400 nm – 2400 nm) reflectance spectra of a wide variety of paints made with historic artists’ pigments have been measured. The best spectral window with which to use optical coherence tomography (OCT) for the imaging of subsurface structure of paintings was found to be around 2.2 μm. The same spectral window would also be most suitable for direct infrared imaging of preparatory sketches under the paint layers. The reflectance spectra from a large sample of chemically verified pigments provide information on the spectral transparency of historic artists’ pigments/paints as well as a reference set of spectra for pigment identification. The results of the paper suggest that broadband sources at ~2 microns are highly desirable for OCT applications in art and potentially material science in general
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