122 research outputs found

    Simple and effective graphene laser processing for neuron patterning application

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    Astraightforward fabrication technique to obtain patterned substrates promoting ordered neuron growth is presented. Chemical vapor deposition (CVD) single layer graphene (SLG) was machined by means of single pulse UV laser ablation technique at the lowest effective laser fluence in order to minimize laser damage effects. Patterned substrates were then coated with poly-D-lysine by means of a simple immersion in solution. Primary embryonic hippocampal neurons were cultured on our substrate, demonstrating an ordered interconnected neuron pattern mimicking the pattern design. Surprisingly, the functionalization is more effective on the SLG, resulting in notably higher alignment for neuron adhesion and growth. Therefore the proposed technique should be considered a valuable candidate to realize a new generation of highly specialized biosensor

    The structure of DNA by direct imaging

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    The structure of DNA was determined in 1953 by x-ray fiber diffraction. Several attempts have been made to obtain a direct image of DNA with alternative techniques. The direct image is intended to allow a quantitative evaluation of all relevant characteristic lengths present in a molecule. A direct image of DNA, which is different from diffraction in the reciprocal space, is difficult to obtain for two main reasons: the intrinsic very low contrast of the elements that form the molecule and the difficulty of preparing the sample while preserving its pristine shape and size. We show that through a preparation procedure compatible with the DNA physiological conditions, a direct image of a single suspended DNA molecule can be obtained. In the image, all relevant lengths of A-form DNA are measurable. A high-resolution transmission electron microscope that operates at 80 keV with an ultimate resolution of 1.5 Å was used for this experiment. Direct imaging of a single molecule can be used as a method to address biological problems that require knowledge at the single-molecule level, given that the average information obtained by x-ray diffraction of crystals or fibers is not sufficient for detailed structure determination, or when crystals cannot be obtained from biological molecules or are not sufficient in understanding multiple protein configurations

    Science communication and concept of risk in bio-tech-sciences: Is it a part of neo-liberalism, or foucaultian bio-politics?

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    In this work a Raman flow cytometer is presented. It consists of a microfluidic device that takes advantages of the basic principles of Raman spectroscopy and flow cytometry. The microfluidic device integrates calibrated microfluidic channels- where the cells can flow one-by-one -, allowing single cell Raman analysis. The microfluidic channel integrates plasmonic nanodimers in a fluidic trapping region. In this way it is possible to perform Enhanced Raman Spectroscopy on single cell. These allow a label-free analysis, providing information about the biochemical content of membrane and cytoplasm of the each cell. Experiments are performed on red blood cells (RBCs), peripheral blood lymphocytes (PBLs) and myelogenous leukemia tumor cells (K562)

    Virtual Reality Analgesia for Pediatric Dental Patients

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    Background: Dental procedures often elicit pain and fear in pediatric dental patients.Aim: To evaluate the feasibility and effectiveness of immersive virtual reality as an attention distraction analgesia technique for pain management in children and adolescents undergoing painful dental procedures.Design: Using a within-subjects design, five patients (mean age 13.20 years old, SD 2.39) participated. Patients received tethered immersive interactive virtual reality distraction in an Oculus Rift VR helmet (experimental condition) during one dental procedure (a single dental filling or tooth extraction). On a different visit to the same dentist (e.g., 1 week later), each patient also received a comparable dental procedure during the control condition “treatment as usual” (treatment order randomized). After each procedure, children self-rated their “worst pain,” “pain unpleasantness,” “time spent thinking about pain,” “presence in VR,” “fun,” and “nausea” levels during the dental procedures, using graphic rating scales.Results: Patients reported significantly lower “worst pain” and “pain unpleasantness,” and had significantly more fun during VR, compared to a comparable dental procedure with No VR. Using Oculus Rift VR goggles, patients reported a “strong sense of going inside the computer-generated world,” without side effects. The dentist preferred having the patients in VR.Conclusion: Results of this pilot study provide preliminary evidence of the feasibility of using immersive, interactive VR to distract pediatric dental patients and increase fun of children during dental procedures

    New results on solar neutrino fluxes from 192 days of Borexino data

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    We report the direct measurement of the ^7Be solar neutrino signal rate performed with the Borexino detector at the Laboratori Nazionali del Gran Sasso. The interaction rate of the 0.862 MeV ^7Be neutrinos is 49+-3(stat)+-4(syst) counts/(day * 100ton). The hypothesis of no oscillation for ^7Be solar neutrinos is inconsistent with our measurement at the 4sigma level. Our result is the first direct measurement of the survival probability for solar nu_e in the transition region between matter-enhanced and vacuum-driven oscillations. The measurement improves the experimental determination of the flux of ^7Be, pp, and CNO solar nu_e, and the limit on the magnetic moment of neutrinos
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