The LHCb detector is a forward spectrometer at the Large Hadron Collider (LHC) at CERN. The experiment is designed for precision measurements of CP violation and rare decays of beauty and charm hadrons. In this paper the performance of the various LHCb sub-detectors and the trigger system are described, using data taken from 2010 to 2012. It is shown that the design criteria of the experiment have been met. The excellent performance of the detector has allowed the LHCb collaboration to publish a wide range of physics results, demonstrating LHCb's unique role, both as a heavy flavour experiment and as a general purpose detector in the forward region.
Fawad Ali, Carlos García A., Aida Hejazi-Nooghabi
et al.
The sound-localization and, in particular, biosonar system of toothed whales is exceptionally performant. How this is achieved is not clear, given that: (i) toothed whales have no pinnae; (ii) while their auditory pathways have been studied in detail, no specific feature apparently replacing the pinna has been identified. In this study, we employ a pseudo-spectral time domain (PSTD) numerical scheme to model three-dimensional elastic wave propagation through a toothed-whale head including soft tissues. Computed tomography (CT) scans were utilized to build a three-dimensional velocity-density model of the specimen's head, parametrized on a high-resolution $1.11$ mm voxel grid. We first validate our wave propagation solver, identifying a range of frequencies and spatial scale lengths where the PSTD scheme captures the complexities of elastic wave propagation through toothed-whale anatomy. We next focus on the toothed whale's ability to locate sources on the median plane, where the role of anatomy is crucial. A 45 kHz central frequency burst (dolphin-like click) was modeled and directed at elevation angles from $-90^\circ$ to $+90^\circ$ in $5^\circ$ steps along the midsagittal plane. We find that the incoming sound can be localized, via correlation, from the reverberated portion of the time-domain waveforms recorded at the tympano-periotic complex locations.
Viktor Nikitin, Gregg Wildenberg, Alberto Mittone
et al.
Despite the increased brilliance of the new generation synchrotron sources, there is still a challenge with high-resolution scanning of very thick and absorbing samples, such as the whole mouse brain stained with heavy elements, and, extending further, brains of primates. Samples are typically cut into smaller parts, to ensure a sufficient X-ray transmission, and scanned separately. Compared to the standard tomography setup where the sample would be cut into many pillars, the laminographic geometry operates with slab-shaped sections significantly reducing the number of sample parts to be prepared, the cutting damage and data stitching problems. In this work, we present a laminography pipeline for imaging large samples (> 1 cm) at micrometer resolution. The implementation includes a low-cost instrument setup installed at the 2-BM micro-CT beamline of the Advanced Photon Source (APS). Additionally, we present sample mounting, scanning techniques, data stitching procedures, a fast reconstruction algorithm with low computational complexity, and accelerated reconstruction on multi-GPU systems for processing large-scale datasets. The applicability of the whole laminography pipeline was demonstrated with imaging 4 sequential slabs throughout the entire mouse brain sample stained with osmium, in total generating approximately 12TB of raw data for reconstruction.
Osteoarthritis (OA) is a widespread, debilitating joint disease associated with articular cartilage degradation. It is driven via mechano-inflammatory catabolic pathways, presumed up-regulated due to increased shear stress on the cartilage-embedded chondrocytes, that lead to tissue degeneration. Here we demonstrate that the up-regulation of the matrix metalloproteinase 3 (Mmp3) and interleukin-1beta (Il1b) genes upon surgical joint destabilization in a model of murine OA is completely suppressed when lipid-based lubricants are injected into the joints. At the same time, Timp1, a compression but not shear-stress sensitive gene, is unaffected by lubricant. Our results provide direct evidence that biolubrication couples to catabolic gene regulation in OA, shed strong light on the nature of the chondrocytes' response to shear stress, and have clear implications for novel OA treatments.
Proprioception is crucial in intuitive control of prosthetic limbs and therefor contributes to intuitive prosthetic use. The agonist-antagonist myoneural interface (AMI) is an prosthetic innovation with enhanced control, reduced pain, and heightened proprioceptive sensation in clinical experiments. Furthermore, studies have addressed surgical techniques to make this myoelectric interface available to a larger group of patients. A narrative review on AMI developmental process, surgical implementations, and validation has been conducted for clinical and pre-clinical experimental research, embedded in a theoretical background on feedback control and proprioception. The closing chapter on magnetomicrometery serves to illustrate how motor control reading, as an example component, can benefit from technical innovations to enhance intuitive prosthetic control in AMI.
Drug resistant bacteria, prions and nosocomial infections underline the need of more effective sterilizing technologies. The cold plasma technology is expected to bring a benefit in this context. Six different plasma sources, based on printed circuit boards, were evaluated fourfold. This include measurements of the power consumption, the ignition behavior by an ICCD-camera and ozone formation by absorption spectroscopy at 254 nm. To evaluate the biocidal effect, four bacterial test series were performed with Escherichia coli. The entirety of the tests analyze the plasma inactivation process from the input parameters to the desired biocidal effect. The discharge current and time resolved ignition behaviors indicated a simultaneous formation of filaments at the beginning of the negative half-cycle. The dynamics of the ozone production showed a saturated exponential growth upon a maximum value of 435 ppm. Additionally, the microbiological test series unveiled differences between the plasma source concepts. A total reduction rate of Log-4 within a minute was achievable. An air flow through slits within the plasma sources destabilized the plasma. Minor changes of the electrode geometry changed all measured parameters. Hence, to develop a pathogen inactivating plasma source, these results recommend a comb-shaped electrode design, which is laminated on a dielectric.
Bryce Manifold, Gabriel F. Dorlhiac, Markita P. Landry
et al.
Chemical neurotransmission is central to neurotypical brain function but also implicated in a variety of psychiatric neurodegenerative diseases. The release dynamics of neurotransmitters is correlated with but distinct from neuronal electrical signal propagation. It is therefore necessary to track neurotransmitter modulation separately from neuron electrical activity. Here, we present a new approach for imaging deuterated neurotransmitter molecules with stimulated Raman scattering (SRS) microscopy. Using SRS microscopy, we perform direct imaging of deuterated dopamine and GABA in PC12 chromaffin cells, and in primary hippocampal neurons, respectively, based on the carbon-deuterium vibrational frequencies. We demonstrate that SRS imaging of these isotopologues directly visualizes intracellular neurotransmitters without changing the neurotransmitters' chemical identity and requiring custom synthesis or genetic encoding protocols. We further show that stimulation of neurotransmitter release results in an overall 20-50 percent intracellular neurotransmitter signal reduction, in agreement with comparable neurotransmission dynamics studies, with the ability to observe inter- and intracellular variation in vesicular neurotransmitter release. Taken together, our data suggest that neurotransmitter isotopologues can serve as a commercially-available, biocompatible, and generalizable method to image neurotransmitters with deuterated molecules that are virtually chemically identical to their native counterparts.
Age-related macular degeneration (AMD) may cause severe loss of vision or blindness particularly in elderly people. Exudative AMD is characterized by angiogenesis of blood vessels growing from underneath the macula, crossing the blood-retina barrier (that comprise Bruch's membrane, BM, and the retinal pigmentation epithelium RPE), leaking blood and fluid into the retina and knocking off photoreceptors. Here, we simulate a computational model of angiogenesis from the choroid blood vessels via a cellular Potts model, as well as BM, RPE cells, drusen deposits and photoreceptors. Our results indicate that improving AMD may require fixing the impaired lateral adhesion between RPE cells and with BM, as well as diminishing Vessel Endothelial Growth Factor (VEGF) and Jagged proteins that affect the Notch signaling pathway. Our numerical simulations suggest that anti-VEGF and anti-Jagged therapies could temporarily halt exudative AMD while addressing impaired cellular adhesion could be more effective on a longer time span.
Gili Dardikman-Yoffe, Simcha K. Mirsky, Itay Barnea
et al.
We present a new acquisition method that enables high-resolution, fine-detail full reconstruction of the three-dimensional movement and structure of individual human sperm cells swimming freely. We achieve both retrieval of the three-dimensional refractive-index profile of the sperm head, revealing its fine internal organelles and time-varying orientation, and the detailed four-dimensional localization of the thin, highly-dynamic flagellum of the sperm cell. Live human sperm cells were acquired during free swim using a high-speed off-axis holographic system that does not require any moving elements or cell staining. The reconstruction is based solely on the natural movement of the sperm cell and a novel set of algorithms, enabling the detailed four-dimensional recovery. Using this refractive-index imaging approach, we believe we have detected an area in the cell that is attributed to the centriole. This method has great potential for both biological assays and clinical use of intact sperm cells.