Carbon nanotube sensor for vibrating molecules

The transport properties of a CNT capacitively coupled to a molecule vibrating along one of its librational modes are studied and its transport properties analyzed in the presence of an STM tip. We evaluate the linear charge and thermal conductances of the system and its thermopower. They are dominated by position-dependent Franck-Condon factors, governed by a position-dependent effective coupling constant peaked at the molecule position. Both conductance and thermopower allow to extract some information on the position of the molecule along the CNT. Crucially, however, thermopower sheds also light on the vibrational levelspacing, allowing to obtain a more complete characterization of the molecule even in the linear regime

Quantum dissipative effects in graphene-like mirrors

We study quantum dissipative effects due to the accelerated motion of a single, imperfect, zero-width mirror. It is assumed that the microscopic degrees of freedom on the mirror are confined to it, like in plasma or graphene sheets. Therefore, the mirror is described by a vacuum polarization tensor $\Pi_{\alpha\beta}$ concentrated on a time-dependent surface. Under certain assumptions about the microscopic model for the mirror, we obtain a rather general expression for the Euclidean effective action, a functional of the time-dependent mirror's position, in terms of two invariants that characterize the tensor $\Pi_{\alpha\beta}$. The final result can be written in terms of the TE and TM reflection coefficients of the mirror, with qualitatively different contributions coming from them. We apply that general expression to derive the imaginary part of the `in-out' effective action, which measures dissipative effects induced by the mirror's motion, in different models, in particular for an accelerated graphene sheet.Comment: 8 pages, 2 figures. Minor changes, version to be published in Phys. Rev.

Towards Micromechanical Sensors with (La,Sr)MnO3 Epitaxial Films☆

Abstract The rich spectrum of functionalities exhibited by oxide thin films is an appealing feature for the development of micro and nanomechanical devices [1,2] . MEMS made of heterostructures of crystalline oxide materials having targeted physical properties may be applied as sensors having different integrated functionalities. In this work, we explore the feasibility of manganite thin film based epitaxial MEMS for magnetic micromechanical sensing. We investigate the electromechanical properties of LSMO freestanding structures for future applications in the field of micromechanical magnetic sensors

Object-based reverberation for spatial audio

Object-based audio is gaining momentum as a means for future audio content to be more immersive, interactive, and accessible. Recent standardization developments make recommendations for object formats; however, the capture, production, and reproduction of reverberation is an open issue. In this paper parametric approaches for capturing, representing, editing, and rendering reverberation over a 3D spatial audio system are reviewed. A framework is proposed for a Reverberant Spatial Audio Object (RSAO), which synthesizes reverberation inside an audio object renderer. An implementation example of an object scheme utilizing the RSAO framework is provided, and supported with listening test results, showing that: the approach correctly retains the sense of room size compared to a convolved reference; editing RSAO parameters can alter the perceived room size and source distance; and, format-agnostic rendering can be exploited to alter listener envelopment

The adaptation of lipid profile of human fibroblasts to alginate 2D films and 3D printed scaffolds

Background: The investigation of the interactions between cells and active materials is pivotal in the emerging 3D printing-biomaterial application fields. Here, lipidomics has been used to explore the early impact of alginate (ALG) hydrogel architecture (2D films or 3D printed scaffolds) and the type of gelling agent (CaCl2 or FeCl3) on the lipid profile of human fibroblasts. Methods: 2D and 3D ALG scaffolds were prepared and characterized in terms of water content, swelling, mechanical resistance and morphology before human fibroblast seeding (8 days). Using a liquid chromatography-triple quadrupole-tandem mass spectrometry approach, selected ceramides (CER), lysophosphatidylcholines (LPC), lysophosphatidic acids (LPA) and free fatty acids (FFA) were analyzed. Results: The results showed a clear alteration in the CER expression profile depending of both the geometry and the gelling agent used to prepare the hydrogels. As for LPCs, the main parameter affecting their distribution is the scaffold architecture with a significant decrease in the relative expression levels of the species with higher chain length (C20 to C22) for 3D scaffolds compared to 2D films. In the case of FFAs and LPAs only slight differences were observed as a function of scaffold geometry or gelling agent. Conclusions: Variations in the cell membrane lipid profile were observed for 3D cell cultures compared to 2D and these data are consistent with activation processes occurring through the mutual interactions between fibroblasts and ALG support. These unknown physiologically relevant changes add insights into the discussion about the relationship between biomaterial and the variations of cell biological functions

PCSK9 ablation attenuates Aβ pathology, neuroinflammation and cognitive dysfunctions in 5XFAD mice

Background: Increasing evidence highlights the importance of novel players in Alzheimer's disease (AD) pathophysiology, including alterations of lipid metabolism and neuroinflammation. Indeed, a potential involvement of Proprotein convertase subtilisin/kexin type 9 (PCSK9) in AD has been recently postulated. Here, we first investigated the effects of PCSK9 on neuroinflammation in vitro. Then, we examined the impact of a genetic ablation of PCSK9 on cognitive performance in a severe mouse model of AD. Finally, in the same animals we evaluated the effect of PCSK9 loss on Aβ pathology, neuroinflammation, and brain lipids. Methods: For in vitro studies, U373 human astrocytoma cells were treated with Aβ fibrils and human recombinant PCSK9. mRNA expression of the proinflammatory cytokines and inflammasome-related genes were evaluated by q-PCR, while MCP-1 secretion was measured by ELISA. For in vivo studies, the cognitive performance of a newly generated mouse line - obtained by crossing 5XFADHet with PCSK9KO mice – was tested by the Morris water maze test. After sacrifice, immunohistochemical analyses were performed to evaluate Aβ plaque deposition, distribution and composition, BACE1 immunoreactivity, as well as microglia and astrocyte reactivity. Cholesterol and hydroxysterols levels in mouse brains were quantified by fluorometric and LC-MS/MS analyses, respectively. Statistical comparisons were performed according to one- or two-way ANOVA, two-way repeated measure ANOVA or Chi-square test. Results: In vitro, PCSK9 significantly increased IL6, IL1B and TNFΑ mRNA levels in Aβ fibrils-treated U373 cells, without influencing inflammasome gene expression, except for an increase in NLRC4 mRNA levels. In vivo, PCSK9 ablation in 5XFAD mice significantly improved the performance at the Morris water maze test; these changes were accompanied by a reduced corticohippocampal Aβ burden without affecting plaque spatial/regional distribution and composition or global BACE1 expression. Furthermore, PCSK9 loss in 5XFAD mice induced decreased microgliosis and astrocyte reactivity in several brain regions. Conversely, knocking out PCSK9 had minimal impact on brain cholesterol and hydroxysterol levels. Conclusions: In vitro studies showed a pro-inflammatory effect of PCSK9. Consistently, in vivo data indicated a protective role of PCSK9 ablation against cognitive impairments, associated with improved Aβ pathology and attenuated neuroinflammation in a severe mouse model of AD. PCSK9 may thus be considered a novel pharmacological target for the treatment of AD

A digital waveguide-based approach for Clavinet modeling and synthesis

The Clavinet is an electromechanical musical instrument produced in the mid-twentieth century. As is the case for other vintage instruments, it is subject to aging and requires great effort to be maintained or restored. This paper reports analyses conducted on a Hohner Clavinet D6 and proposes a computational model to faithfully reproduce the Clavinet sound in real time, from tone generation to the emulation of the electronic components. The string excitation signal model is physically inspired and represents a cheap solution in terms of both computational resources and especially memory requirements (compared, e.g., to sample playback systems). Pickups and amplifier models have been implemented which enhance the natural character of the sound with respect to previous work. A model has been implemented on a real-time software platform, Pure Data, capable of a 10-voice polyphony with low latency on an embedded device. Finally, subjective listening tests conducted using the current model are compared to previous tests showing slightly improved results

Morphometric investigation on osteocytes in human auditory ossicles

An osteocyte lacunae differential count (1-lacunae with live osteocytes, 2-lacunae with degenerating osteocytes, 3-empty lacunae) was carried out on ear ossicles and clavicles from cadavers as well as on stapes removed by stapedotomy. The distance of the three types of lacunae from the vascular source was also determined by a computer-assisted light microscope. Results showed that the delayed fixation of bone from cadavers does not significantly interfere with osteocyte preservation, at least with the scope of this investigation. The results of osteocyte differential count show that the number of empty lacunae and lacunae with degenerating osteocytes: (a) is significantly higher in ear ossicles than in clavicles, (b) increases with age, (c) is higher in stapes than in incuses and mallei, (d) increases with the distance from the vascular sources in both ear ossicles and clavicles. Additionally it appeared that the process of osteocyte degeneration in ear ossicles is very rapid and widespread, over 40% of the cells being dead within the 2nd year of age. In the light of the recent literature and personal findings, which ascribe to osteocytes the function of mechanical detectors, and considering that bone remodeling occasionally occurs in ear ossicles, it is postulated that osteocyte death in these bones could be a programmed phenomenon (apoptosis?), due to which they lose the ability to react to strains and stresses and achieve the structural stability they need to perform their peculiar stereotyped function

Alginate Self‐Crosslinking Ink for 3D Extrusion‐Based Cryoprinting and Application for Epirubicin‐HCl Delivery on MCF‐7 Cells

3D‐printed hydrogels are particularly advantageous as drug‐delivery platforms but their loading with water‐soluble active compounds remains a challenge requiring the development of innovative inks. Here, we propose a new 3D extrusion‐based approach that, by exploiting the internal gelation of the alginate, avoids the post‐printing crosslinking process and allows the loading of epirubicin‐HCl (EPI). The critical combinations of alginate, calcium carbonate and d‐ glucono‐δ‐lactone (GDL) combined with the scaffold production parameters (extrusion time, temperature, and curing time) were evaluated and discussed. The internal gelation in tandem with 3D extrusion allowed the preparation of alginate hydrogels with a complex shape and good handling properties. The dispersion of epirubicin‐HCl in the hydrogel matrix confirmed the potential of this self‐crosslinking alginate‐based ink for the preparation of 3D‐printed drug‐delivery platforms. Drug release from 3D‐printed hydrogels was monitored, and the cytotoxic activity was tested against MCF‐7 cells. Finally, the change in the expression pattern of anti‐apoptotic, pro-apoptotic, and autophagy protein markers was monitored by liquid‐chromatography tandem-mass‐spectrometry after exposure of MCF‐7 to the EPI‐loaded hydrogels

Visualization of compact microphone array room impulse responses

For many audio applications, availability of recorded multi-channel room impulse responses (MC-RIRs) is fundamental. They enable development and testing of acoustic systems for reflective rooms. We present multiple MC-RIR datasets recorded in diverse rooms, using up to 60 loudspeaker positions and various uniform compact microphone arrays. These datasets complement existing RIR libraries and have dense spatial sampling of a listening position. To reveal the encapsulated spatial information, several state of the art room visualization methods are presented. Results confirm the measurement fidelity and graphically depict the geometry of the recorded rooms. Further investigation of these recordings and visualization methods will facilitate object-based RIR encoding, integration of audio with other forms of spatial information, and meaningful extrapolation and manipulation of recorded compact microphone array RIRs