To be or not to be a conodont. The controversial story of Pseudooneotodus and Eurytholia

The genus Pseudooneotodus (Drygant, 1974) is a genus of small and conical elements widely distributed from the Middle Ordovician to the Early Devonian throughout the world. Because of its unusual shape, Pseudooneotodus has long been considered enigmatic, and only in the late nineties of the last century the genus has been finally placed within conodonts according to histological data. This study investigates possible similarities between Pseudooneotodus and Eurytholia (Sutton et al., 2001), an incertae sedis genus of enigmatic plates with a phosphate composition. An association of over one hundred specimens of Pseudooneotodus beckmanni and Eurytholia bohemica was analyzed from conodont residues in two distinct geographical areas: the Prague Basin (Požáry and Mušlovka sections, Bohemia, Czech Republic) and the Carnic Alps (Rauchkofel Boden section, Austria). Through an investigation that combines the use of optical and electron microscopy (including focused ion beam scanning electron microscopy), X-ray microdiffraction, and trace element (HFSE) analysis by mass spectrometry, differences between these fossil groups were observed and compared with data resulting from typical conodonts (Dapsilodus obliquicostatus, Panderodus unicostatus and Wurmiella excavata) recovered from the same samples

Autonomous Non-Equilibrium Self-Assembly and Molecular Movements Powered by Electrical Energy

The ability to exploit energy autonomously is one of the hallmarks of life. Mastering such processes in artificial nanosystems can open technological opportunities. In the last decades, light- and chemically driven autonomous systems have been developed in relation to conformational motion and self-assembly, mostly in relation to molecular motors. In contrast, despite electrical energy being an attractive energy source to power nanosystems, its autonomous harnessing has received little attention. Herein we consider an operation mode that allows the autonomous exploitation of electrical energy by a self-assembling system. Threading and dethreading motions of a pseudorotaxane take place autonomously in solution, powered by the current flowing between the electrodes of a scanning electrochemical microscope. The underlying autonomous energy ratchet mechanism drives the self-assembly steps away from equilibrium with a higher energy efficiency compared to other autonomous systems. The strategy is general and might be extended to other redox-driven systems

3D Bioprinting for Musculoskeletal Applications

This review focuses on developments in the field of bioprinting for musculoskeletal tissue engineering, along with discussion on the various approaches for bone, cartilage and connective tissue fabrication. All approaches (cell-laden, cell-free and a combination of both) aim to obtain a complex, living tissues able to develop and mature, using the same fundamental technology. To date, co-printing of cell-laden and cell-free materials has been revealed to be the most promising approach for musculoskeletal applications because materials with good bioactivity and good mechanical strength can be combined within the same constructs. Bioprinting for musculoskeletal applications is a developing field, and detailed discussion on the current challenges and future perspectives is also presented in this review

Light-Triggered Electron Transfer between a Conjugated Polymer and Cytochrome C for Optical Modulation of Redox Signaling

Protein reduction/oxidation processes trigger and finely regulate a myriad of physiological and pathological cellular functions. Many biochemical and biophysical stimuli have been recently explored to precisely and effectively modulate intracellular redox signaling, due to the considerable therapeutic potential. Here, we propose a first step toward an approach based on visible light excitation of a thiophene-based semiconducting polymer (P3HT), demonstrating the realization of a hybrid interface with the Cytochrome c protein (CytC), in an extracellular environment. By means of scanning electrochemical microscopy and spectro-electrochemistry measurements, we demonstrate that, upon optical stimulation, a functional interaction between P3HT and CytC is established. Polymer optical excitation locally triggers photoelectrochemical reactions, leading to modulation of CytC redox activity, either through an intermediate step, involving reactive oxygen species formation, or via a direct photoreduction process. Both processes are triggered by light, thus allowing excellent spatiotemporal resolution, paving the way to precise modulation of protein redox signaling

Low-flow ischemia and hypoxia stimulate apoptosis in perfused rat hearts independently of reperfusion

Post-ischemic reperfusion leads to apoptosis-linked loss of myocytes in cultured cells and in vivo. We tested the hypothesis that apoptosis develops without reperfusion in Langendorff-perfused hearts exposed to either low-flow ischemia (LFI) or hypoxia (H). Rat hearts were perfused with aminoacid-enriched Krebs- Henseleit buffer and exposed for 6 h to LFI (flow=2 ml/min, PO2=500\ub150mmHg, mean\ub1SD), H (10ml/min, 120\ub115mmHg), or control conditions (C, 10ml/min, 500\ub150mmHg). At selected times, DNA-fragmentation was measured by agarose-gel electrophoresis and in situ TUNEL assay. After 6 h, the ratio (TUNEL-positi- ve)/(total nuclei) was 0.620\ub10.027, 0.615\ub10.005, 0.404\ub10.021 in LFI, H and C, respectively. The ratio was 0.813\ub10.021 in hearts exposed to 90 min global no-flow ischemia and reperfused (5 h). To assess the role of membrane-diffusible factors, separate experiments were performed recirculating the medium and exposing hearts to LFI or H as above. The degree of apoptosis was the same in both the recirculating and non-recirculating modes. Thus, apoptosis develops by similar extents and in a time-dependent fashion in crystalloid-perfused rat hearts during LFI or H at the same oxygen shortage (flow\u2022PO2), even without the reperfusion

Arylboronate esters mediated self-healable and biocompatible dynamic G-quadruplex hydrogels as promising 3D-bioinks

Extrudable G-quadruplex hydrogels were prepared at physiological pH. Gels with suitable mechanical properties were explored as 3D-bioinks. The 3D printing process is driven by injectability and the highly thixotropic and self-healable nature of the gel. High cell viability and homogeneous cell distribution within the gel make it a promising material as a 3D bioink

Application of high resolution DLP stereolithography for fabrication of tricalcium phosphate scaffolds for bone regeneration

Bone regeneration requires porous and mechanically stable scaffolds to support tissue integration and angiogenesis, which is essential for bone tissue regeneration. With the advent of additive manufacturing process, production of complex porous architecture has become feasible. However, a balance has to be sorted between porous architecture and mechanical stability which facilitates bone regeneration for load bearing applications. 
 Current study evaluates used of high resolution digital light processing (DLP) -based additive manufacturing to produce complex but mechanical stable scaffolds based on β-tricalcium phosphate (β-TCP) for bone regeneration. 
 Four different geometries, a rectilinear Grid, hexagonal Kagome, schwart primitive and hollow Schwarz are designed with 400 µm pores and 75 or 50 vol.% porosity. However after initial screening for design stability and mechanical properties, only a rectilinear Grid structure, a hexagonal Kagome structure are found to be reproducible and showed higher mechanical properties. 
 Micro computed tomography (µ-CT) analysis shows < 2 vol.% error in porosity and < 6 % relative deviation of average pore sizes for the Grid structures. At 50 vol.% porosity, this architecture also has the highest compressive strength of 44.7 MPa (Weibull modulus is 5.28), while bulk specimens reach 235 ± 37 MPa. 
 To evaluate suitability of 3D scaffolds produce by DLP methods for bone regeneration, scaffolds were cultured with murine preosteoblastic MC3T3-E1 cells. Short term study showed cells growth over 14 days, with more than two-fold increase of alkaline phosphatase (ALP) activity compared to cells on 2D tissue culture plastic. Collagen deposition was increased by a factor of 1.5 – 2 when compared to the 2D controls. This confirm retention of biocompatible and osteo-inductive properties of β-TCP following DLP process. 
 This study has implications for designing of the high resolution porous scaffolds for bone regenerative applications and contributes to understanding of DLP based additive manufacturing process for medical applications

Numerical simulations on laser absorption enhancement in hybrid metallo-dielectric nanostructured targets for future nuclear astrophysics experiments

The linear electromagnetic interaction between innovative hybrid metallo-dielectric nanostructured targets and laser in visible and IR range is investigated through numerical simulations. The obtained results rely on the optimization of a target based on metallic nanowires (NWs) to enhance light absorption in the visible range of the electromagnetic spectrum. The NWs are grown within the ordered nanoholes of an alumina substrate, thus, forming a plasmonic lattice with triangular symmetry. The remaining volume of the nanoholes on top of the NWs is sealed with a transparent layer of aluminum oxide that is suitable to be chemically modified for containing about 25% of deuterium atoms. The study presented here is carried out within the framework of a scientific program named PLANETA (Plasmonic Laser Absorption on Nano-Engineered Targets) aiming at investigating new laser–matter interaction schemes in the ns domain and for nuclear fusion purposes, involving especially the D–D reaction

Inclusive Search for Anomalous Production of High-pT Like-Sign Lepton Pairs in Proton-Antiproton Collisions at sqrt{s}=1.8 TeV

We report on a search for anomalous production of events with at least two charged, isolated, like-sign leptons with pT > 11 GeV/c using a 107 pb^-1 sample of 1.8 TeV ppbar collisions collected by the CDF detector. We define a signal region containing low background from Standard Model processes. To avoid bias, we fix the final cuts before examining the event yield in the signal region using control regions to test the Monte Carlo predictions. We observe no events in the signal region, consistent with an expectation of 0.63^(+0.84)_(-0.07) events. We present 95% confidence level limits on new physics processes in both a signature-based context as well as within a representative minimal supergravity (tanbeta = 3) model.Comment: 15 pages, 4 figures. Minor textual changes, cosmetic improvements to figures and updated and expanded reference