Synchrotron radiation reveals the identity of the large felid from Monte Argentario (Early Pleistocene, Italy)

We describe here a partial skull with associated mandible of a large felid from Monte Argentario, Italy (Early Pleistocene; ~1.5 million years). Propagation x-ray phase-contrast synchrotron microtomography of the specimen, still partially embedded in the rock matrix, allows ascribing it reliably to Acinonyx pardinensis, one of the most intriguing extinct carnivorans of the Old World Plio-Pleistocene. The analysis of images and 3D models obtained through synchrotron microtomography – here applied for the first time on a Plio-Pleistocene carnivoran – reveals a mosaic of cheetah-like and Panthera-like features, with the latter justifying previous attributions of the fossil to the extinct Eurasian jaguar Panthera gombaszoegensis. Similarly, we reassign to A. pardinensis some other Italian materials previously referred to P. gombaszoegensis (sites of Pietrafitta and Ellera di Corciano). The recognition of Panthera-like characters in A. pardinensis leads to reconsidering the ecological role of this species, whose hunting strategy was likely to be different from those of the living cheetah. Furthermore, we hypothesise that the high intraspecific variation in body size in A. pardinensis can be the result of sexual dimorphism, as observed today in all large-sized felids

Picosecond Internal Dynamics of Lysozyme as Affected by Thermal Unfolding in Nonaqueous Environment

AbstractA neutron-scattering investigation of the internal picosecond dynamics of lysozyme solvated in glycerol as a function of temperature in the range 200–410K has been undertaken. The inelastic contribution to the measured intensity is characterized by the presence of a bump generally known as “boson peak”, clearly distinguishable at low temperature. When the temperature is increased the quasielastic component of the spectrum becomes more and more intrusive and progressively overwhelms the vibrational bump. This happens especially for T>345K when the protein goes through an unfolding process, which leads to the complete denaturation. The quasielastic term is the superposition of two components whose intensities and linewidths have been studied as a function of temperature. The slower component describes motions with characteristic times of ∼4ps corresponding to reorientations of polypeptide side chains. Both the intensity and linewidth of this kind of relaxations show two distinct regimes with a crossover in the temperature range where the melting process occurs, thus suggesting the presence of a dynamical transition correlated to the protein unfolding. Conversely the faster component might be ascribed to the local dynamics of hydrogen atoms caged by the nearest neighbors with characteristic time of ∼0.3ps

TEMPO-oxidized cellulose nanofibril/polyvalent cations hydrogels: a multifaceted view of network interactions and inner structure

In the last years, hydrogels from renewable biopolymers and low-cost row materials are a hot topic for biomedical applications. In this context, cellulose nanofibrils are considered suitable building blocks for the synthesis of many biocompatible products, with a variety of chemical-physical properties. Herein we report a multi-technique and multi-scale study, from the molecular to the nanometric length scale, of the sol-gel transition observed in aqueous solutions of TEMPO-oxidized nano-sized cellulose fibrils (TOCNFs), when in the presence of polyvalent cations (Mg2+ and Ca2+). We combine the data from Small Angle Neutron Scattering (SANS), which provide information about the inner structure of the nanofibril, with those from UV Resonant Raman (UVRR) spectroscopy, which is a sensitive probe of the intra- and inter-molecular interactions in the gel and the liquid state. The transition between the gel and the liquid phases is investigated as a function of the concentration of both TOCNFs and cations, the nature of the latter, and the pH at which the phenomenon is observed. SANS analysis reveals that ion concentration induces an anisotropic swelling in the nanofibrils which, at the same time, become more and more flexible. The nanofibrils flexibility is also dependent on TOCNF concentration and pH value. UVRR allows us to elucidate the structural organization and hydrogen-bonding properties of water in aqueous TOCNF dispersions and gels, showing how water molecules partially lose their typical bulk-like tetrahedral organization when ions are added, and the gel phase is formed

A large-area double rotating-crystal monochromator for time-focusing neutron instruments

We present the principle and the first prototypes of a double rotating-crystal monochromator, based on an assembly of smaller rotating elements. Such a device was developed as the key element to implement a parallel-beam modification of the time-focusing technique for neutron spectrometers. This concept is particularly promising for long-pulse sources and can bring specific advantages on continuous sources as well. Neutron tests performed on the first prototypes validate the mechanical reliability of the proposed design and the feasibility of a large-area double rotating-crystal monochromator based on this technology

European Stroke Organisation (ESO) guideline on screening for subclinical atrial fibrillation after stroke or transient ischaemic attack of undetermined origin

We aimed to provide practical recommendations for the screening of subclinical atrial fibrillation (AF) in patients with ischaemic stroke or transient ischaemic attack (TIA) of undetermined origin. These guidelines are based on the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology. Five relevant Population, Intervention, Comparator, Outcome questions were defined by a multidisciplinary module working group (MWG). Longer duration of cardiac rhythm monitoring increases the detection of subclinical AF, but the optimal monitoring length is yet to be defined. We advise longer monitoring to increase the rate of anticoagulation, but whether longer monitoring improves clinical outcomes needs to be addressed. AF detection does not differ from in- or out-patient ECG-monitoring with similar monitoring duration, so we consider it reasonable to initiate in-hospital monitoring as soon as possible and continue with outpatient monitoring for more than 48 h. Although insertable loop recorders (ILR) increase AF detection based on their longer monitoring duration, comparison with non-implantable ECG devices for similar monitoring time is lacking. We suggest the use of implantable devices, if feasible, for AF detection instead of non-implantable devices to increase the detection of subclinical AF. There is weak evidence of a useful role for blood, ECG and brain imaging biomarkers for the identification of patients at high risk of AF. In patients with patent foramen ovale, we found insufficient evidence from RCT, but prolonged cardiac monitoring in patients >55 years is advisable for subclinical AF detection. To conclude, in adult patients with ischaemic stroke or TIA of undetermined origin, we recommend longer duration of cardiac rhythm monitoring of more than 48 h and if feasible with IRL to increase the detection of subclinical AF

Double dynamical regime of confined water

The Van Hove self correlation function of water confined in a silica pore is calculated from Molecular Dynamics trajectories upon supercooling. At long time in the $\alpha$ relaxation region we found that the behaviour of the real space time dependent correlators can be decomposed in a very slow, almost frozen, dynamics due to the bound water close to the substrate and a faster dynamics of the free water which resides far from the confining surface. For free water we confirm the evidences of an approach to a crossover mode coupling transition, previously found in Q space. In the short time region we found that the two dynamical regimes are overimposed and cannot be distinguished. This shows that the interplay between the slower and the faster dynamics emerges in going from early times to the $\alpha$ relaxation region, where a layer analysis of the dynamical properties can be performed.Comment: 6 pages with 9 figures. RevTeX. Accepted for pulbication in J. Phys. Cond. Mat

Prevention of venous thromboembolism in acute spontaneous intracerebral haemorrhage: A survey of opinion

INTRODUCTION: People immobilized following acute spontaneous intracerebral haemorrhage (ICH) are at risk of venous thromboembolism (VTE) but the role of short-term prophylactic anticoagulation remains uncertain. We surveyed UK clinical practice and opinion regarding preventing VTE after ICH. PATIENTS AND METHODS: An online survey was sent to stroke healthcare professionals within the United Kingdom and Ireland via a professional society (British and Irish Association of Stroke Physicians (BIASP)). RESULTS: One hundred and twenty-three staff members responded to the survey, of whom 80% were consultant stroke physicians. All responders except one considered the issue to be important or extremely important, but only 5 (4%) were “extremely certain” and 51 (41%) “fairly certain” regarding the optimal treatment approach. Intermittent pneumatic compression (IPC) devices alone were the most used method (in 60%) followed by IPC devices and switching to low molecular weight heparin (LMWH) (in 30%). We identified high levels of uncertainty regarding the role of anticoagulation, and its optimal timing; uncertainty was greater in lobar compared to deep ICH. Most respondents (93%) consider a randomised controlled trial investigating the role of pharmacological VTE prophylaxis after acute ICH as important and would consider participation. DISCUSSION AND CONCLUSION: The optimal method for the prevention of VTE in non-traumatic ICH patients remains an area of clinical uncertainty. Clinical trials assessing short-term anticoagulation in patients after acute ICH would be beneficial in providing evidence to resolve this clinical dilemma