How the hydrogen bond in NH4_4F is revealed with Compton scattering

In order to probe electron wave functions involved in the bonding of NH$_4$F, we have performed Compton scattering experiments in an oriented single crystal and in a powder. Ab initio calculations of the Compton profiles for NH$_4$F and NH$_4$Cl are used to enlighten the nature of the bonds in the NH$_4$F crystal. As a consequence, we are able to show significant charge transfer in the ammonium ion which is not observable using other methods. Our study provides a compelling proof for hydrogen bond formation in NH$_4$F.Comment: 4 pages, 5 figures, accepted for publication as a Regular Article in Physical Review

Graphene-based nanomaterials for tissue engineering in the dental field

The world of dentistry is approaching graphene-based nanomaterials as substitutes for tissue engineering. Apart from its exceptional mechanical strength, electrical conductivity and thermal stability, graphene and its derivatives can be functionalized with several bioactive molecules. They can also be incorporated into different scaffolds used in regenerative dentistry, generating nanocomposites with improved characteristics. This review presents the state of the art of graphene-based nanomaterial applications in the dental field. We first discuss the interactions between cells and graphene, summarizing the available in vitro and in vivo studies concerning graphene biocompatibility and cytotoxicity. We then highlight the role of graphene-based nanomaterials in stem cell control, in terms of adhesion, proliferation and differentiation. Particular attention will be given to stem cells of dental origin, such as those isolated from dental pulp, periodontal ligament or dental follicle. The review then discusses the interactions between graphene-based nanomaterials with cells of the immune system; we also focus on the antibacterial activity of graphene nanomaterials. In the last section, we offer our perspectives on the various opportunities facing the use of graphene and its derivatives in associations with titanium dental implants, membranes for bone regeneration, resins, cements and adhesives as well as for tooth-whitening procedure

2D:4D digit ratio and religiosity in university student and general population samples

The ratio of index to ring finger length (2D:4D) is used as a proxy for prenatal sex hormone exposure. It has been hypothesised to correlate with religiosity, though no published research has explored this possibility. Here, we initially examined 2D:4D in relation to self-reported religious affiliation and questionnaire measures of general religiosity, spirituality, religious fundamentalism, and religious commitment in male (N = 106) and female (N = 105) university students (Study 1). Although no significant correlations were observed between 2D:4D and the questionnaire measures, females who affiliated with organised religions had higher right and left hand digit ratios compared to agnostic or atheist females. Study 2 attempted to replicate these findings in an adult general population sample (N = 172 males, N = 257 females), but did not observe significant effects in either sex. Overall, these findings suggest that high 2D:4D may be relatively-specifically associated with increased religious affiliation in young, highly-educated, females.This work was supported by a Student Research Grant from the European Human Behaviour and Evolution Association (EHBEA), and an Experimental Psychology Society (EPS) Grindley Grant awarded to GR. The work was partially undertaken within the Medical Research Council UK Centre for Neuropsychiatric Genetics and Genomics (MR/L010305/1). The funders played no role in study design, data collection, analysis and interpretation, writing of the manuscript, or the decision to submit the article for publication

Metastatic Pancreatic Adenocarcinoma After Total Pancreatectomy Islet Autotransplantation for Chronic Pancreatitis

Total pancreatectomy with islet autotransplantation (TPIAT) is being used increasingly as a definitive treatment for chronic pancreatitis. Patients with chronic pancreatitis have an elevated risk of pancreatic cancer, which can also masquerade as acute or chronic pancreatitis, making the diagnosis challenging. We describe here the first case of pancreatic ductal adenocarcinoma developing in the liver of a patient after TPIAT for presumed benign chronic pancreatitis. Retrospective analysis of the patient’s preoperative serum revealed normal carbohydrate antigen 19-9 and carcinoembryonic antigen levels but elevated levels of microRNAs -10b, -30c, and -106b compared with controls. Screening guidelines are important to reduce the risk of transplantation of malignant tissue. More sensitive screening tools, including the potential use of microRNAs, are needed to detect early preclinical disease, given the highly malignant nature of pancreatic cancer

Hydrogen bonding and coordination in normal and supercritical water from X-ray inelastic scattering

A direct measure of hydrogen bonding in water under conditions ranging from the normal state to the supercritical regime is derived from the Compton scattering of inelastically-scattered X-rays. First, we show that a measure of the number of electrons $n_e$ involved in hydrogen bonding at varying thermodynamic conditions can be directly obtained from Compton profile differences. Then, we use first-principles simulations to provide a connection between $n_e$ and the number of hydrogen bonds $n_{HB}$. Our study shows that over the broad range studied the relationship between $n_e$ and $n_{HB}$ is linear, allowing for a direct experimental measure of bonding and coordination in water. In particular, the transition to supercritical state is characterized by a sharp increase in the number of water monomers, but also displays a significant number of residual dimers and trimers.Comment: 14 pages, 5 figures, 1 tabl

Phonon dispersion and lifetimes in MgB2

We measure phonon dispersion and linewidth in a single crystal of MgB_2 along the Gamma-A, Gamma-M and A-L directions using inelastic X-Ray scattering. We use Density Functional Theory to compute the effect of both electron-phonon coupling and anharmonicity on the linewidth, obtaining excellent agreement with experiment. Anomalous broadening of the E_2g phonon mode is found all along Gamma-A. The dominant contribution to the linewidth is always the electron-phonon coupling.Comment: 4 pages, 3 figure

Wireless Sensor Network Deployment for Monitoring Soil Moisture Dynamics at the Field Scale

AbstractWe describe the deployment of a Wireless Sensor Network (WSN), composed of 135 soil moisture and 27 temperature sensors, in an apple tree orchard of about 5000 m2, located in the municipality of Cles, a small town in the Alpine region, northeastern Italy. The orchard is divided into three parcels each one subjected to a different irrigation schedule. The objective of the present work is to monitor soil moisture dynamics in the top soil to a detail, in both space and time, suitable to analyze the interplay between soil moisture dynamics and plant physiology. The deployment consists of 27 locations (verticals) connected by a multi hop WSN, each one equipped with 5 soil moisture sensors deployed at the depths of 10, 20, 30, 50 and 80 cm, and a temperature sensor at the depth of 20 cm. The proposed monitoring system is based on totally independent sensor nodes, which allow both real time and historic data management and are connected through an input/output interface to a WSN platform. Meteorological data are monitored by a weather station located at a distance of approximately 100 m from the experimental site.Great care has been posed to calibration of the capacitance sensors, both in the laboratory, with soil samples, and on site, after deployment, in order to minimize the noise caused by small oscillations in the input voltage and uncertainty in the calibration curves. In this work we report the results of a preliminary analysis on the data collected during the growing season 2009. We observed that the WSN greatly facilitates the collection of detailed measurements of soil moisture, thereby increasing the amount of information useful for exploring hydrological processes, but they should be used with care since the accuracy of collected data depends critically on the capability of the system to maintain constant the input voltage and on the reliability of calibration curves. Finally, we studied the spatial and temporal distribution of soil moisture in all the irrigated parcels, and explored how different irrigation schedules influence orchard's production

Calcium as a key player in arrhythmogenic cardiomiopathy : adhesion disorder or intracellular alteration?

Arrhythmogenic cardiomyopathy (ACM) is an inherited heart disease characterized by sudden death in young people and featured by fibro-adipose myocardium replacement, malignant arrhythmias, and heart failure. To date, no etiological therapies are available. Mutations in desmosomal genes cause abnormal mechanical coupling, trigger pro-apoptotic signaling pathways, and induce fibro-adipose replacement. Here, we discuss the hypothesis that the ACM causative mechanism involves a defect in the expression and/or activity of the cardiac Ca2+ handling machinery, focusing on the available data supporting this hypothesis. The Ca2+ toolkit is heavily remodeled in cardiomyocytes derived from a mouse model of ACM defective of the desmosomal protein plakophilin-2. Furthermore, ACM-related mutations were found in genes encoding for proteins involved in excitation\u2012contraction coupling, e.g., type 2 ryanodine receptor and phospholamban. As a consequence, the sarcoplasmic reticulum becomes more eager to release Ca2+, thereby inducing delayed afterdepolarizations and impairing cardiac contractility. These data are supported by preliminary observations from patient induced pluripotent stem-cell-derived cardiomyocytes. Assessing the involvement of Ca2+ signaling in the pathogenesis of ACM could be beneficial in the treatment of this life-threatening disease

\u3cem\u3eIn situ\u3c/em\u3e pressure study of Rb\u3csub\u3e4\u3c/sub\u3eC\u3csub\u3e60\u3c/sub\u3e insulator to metal transition by Compton scattering

Compton scattering has been shown to be a powerful tool for studying the ground state electronic density in real materials. Using synchrotron radiation, we have studied pressure effects on Rb4C60 by measuring the Compton profiles below and above the insulator to metal transition at 0.8 GPa. The experimental results are compared with the corresponding calculated results, obtained from new ab initio energy band structure calculations. These results allow us to quantitatively evaluate contributions to the Compton profiles resulting from the contraction of the unit cell as well as from the contraction of the C60 molecule itself. In this paper, we point out an unexpected contraction of the volume of the C60 molecule, leading to a major effect on the electronic density of the Rb4C60 compound