Intercalation and reactions of CO under single layer graphene/Ni(111): the role of vacancies.

We use synchrotron radiation-induced core level photoemission spectroscopy to investigate the influence of vacancies, produced by ion bombardment, on monolayer graphene/Ni(111) exposed to CO at pressures ranging from ultra-high vacuum (10-10 mbar) up to near ambient (5.6 mbar) conditions. CO intercalates at a rate which is comparable to the one observed in absence of defects and reacts via the Boudouard reaction producing additional carbon atoms and CO2. While the former attach to the graphene layer and extend it over areas previously covered by carbide, the CO2 molecules bind to the graphene vacancies forming epoxy-like bonds across them, thus mending the defects. The so-formed complexes give rise to a peak at 533.4 eV which persists upon evacuating the vacuum chamber at room temperature and which we assign to a covalently bonded species containing C and O.

Ecotoxicity of Polyvinylidene Difluoride (PVDF) and Polylactic Acid (PLA) Microplastics in Marine Zooplankton.

The aim of this study was to investigate the ecotoxicity of polyvinylidene difluoride (PVDF) and polylactic acid (PLA) microplastics (MPs) in two marine zooplankton: the crustacean Artemia franciscana and the cnidarian Aurelia sp. (common jellyfish). To achieve this goal, (i) MP uptake, (ii) immobility, and (iii) behavior (swimming speed, pulsation mode) of crustacean larval stages and jellyfish ephyrae exposed to MPs concentrations (1, 10, 100 mg/L) were assessed for 24 h. Using traditional and novel techniques, i.e., epifluorescence microscopy and 3D holotomography (HT), PVDF and PLA MPs were found in the digestive systems of the crustaceans and in the gelatinous tissue of jellyfish. Immobility was not affected in either organism, while a significant behavioral alteration in terms of pulsation mode was found in jellyfish after exposure to both PVDF and PLA MPs. Moreover, PLA MPs exposure in jellyfish induced a toxic effect (EC50: 77.43 mg/L) on the behavioral response. This study provides new insights into PLA and PVDF toxicity with the potential for a large impact on the marine ecosystem, since jellyfish play a key role in the marine food chain. However, further investigations incorporating additional species belonging to other trophic levels are paramount to better understand and clarify the impact of such polymers at micro scale in the marine environment. These findings suggest that although PVDF and PLA have been recently proposed as innovative and, in the case of PLA, biodegradable polymers, their effects on marine biota should not be underestimated.

Adsorption of glutamic acid on clean and hydroxylated rutile TiO2(110): an XPS and NEXAFS investigation.

Due to its biocompatibility, TiO2is a relevant material for the study of bio-interfaces. Its electronic and chemical properties are influenced by defects, which mainly consist of oxygen vacancies or adsorbed OH groups and which affect, consequently, also the interaction with biological molecules. Here we report on an x-ray photoemission spectroscopy and near edge adsorption fine structure study of glutamic acid (Glu) adsorption on the rutile TiO2(110) surface, either clean or partially hydroxylated. We show that Glu anchors to the surface through a carboxylate group and that the final adsorption state is influenced by the presence of hydroxyl groups on the surface prior to Glu deposition. Indeed, molecules adsorb both in the anionic and in the zwitterionic form, the former species being favored on the hydroxylated substrate.

Morphological characterization and electronic properties of pristine and oxygen-exposed graphene nanoribbons on Ag(110).

Graphene nanoribbons (GNRs) are at the frontier of research on graphene materials since the 1D quantum confinement of electrons allows for the opening of an energy gap. GNRs of uniform and well-defined size and shape can be grown using the bottom-up approach, i.e. by surface assisted polymerization of aromatic hydrocarbons. Since the electronic properties of the nanostructures depend on their width and on their edge states, by careful choice of the precursor molecule it is possible to design GNRs with tailored properties. A key issue for their application in nanoelectronics is their stability under operative conditions. Here, we characterize pristine and oxygen-exposed 1.0 nm wide GNRs with a well-defined mixed edge-site sequence (two zig-zag and one armchair) synthesized on Ag(110) from 1,6-dibromo-pyrene precursors. The energy gap and the presence of quantum confined states are investigated by scanning tunneling spectroscopy. The effect of oxygen exposure under ultra-high vacuum conditions is inferred from scanning tunneling microscopy images and photoemission spectra. Our results demonstrate that oxygen exposure deeply affects the overall system by interacting both with the nanoribbons and with the substrate; this factor must be considered for supported GNRs under operative conditions.

Feasibility of using a novel instrumented human head surrogate to measure helmet, head and brain kinematics and intracranial pressure during multidirectional impact tests.

OBJECTIVES: Aim of the work is to present the feasibility of using an Instrumented Human Head Surrogate (IHHS-1) during multidirectional impacts while wearing a modern ski helmet. The IHHS-1 is intended to provide reliable and repeatable data for the experimental validation of FE models and for the experimental evaluation of modern helmets designed to enhance the degree of protection against multidirectional impacts. DESIGN: The new IHHS-1 includes 9 triaxial MEMS accelerometers embedded in a silicone rubber brain, independently molded and presenting lobes separation and cerebellum, placed into an ABS skull filled with surrogate cerebrospinal fluid. A triaxial MEMS gyroscope is placed at the brain center of mass. Intracranial pressure can be detected by eight pressure sensors applied to the skull internal surface along a transversal plane located at the brain center of mass and two at the apex. Additional MEMS sensors positioned over the skull and the helmet allow comparison between outer and inner structure kinematics and surrogate CSF pressure behavior. METHODS: The IHHS-1 was mounted through a Hybrid III neck on a force platform and impacted with a striker connected to a pendulum tower, with the impact energies reaching 24J. Impact locations were aligned with the brain center of mass and located in the back (sagittal axis), right (90° from sagittal axis), back/right (45°), and front right (135°) locations. Following dynamic data were collected: values of the linear accelerations and angular velocities of the brain, skull and helmet; intracranial pressures inside the skull. RESULTS: Despite the relatively low intensity of impacts (HIC at skull max value 46), the skull rotational actions reached BrIC values of 0.33 and angular accelerations of 5216rad/s2, whereas brain angular acceleration resulted between 1,44 and 2,1 times lower with similar values of BrIC. CONCLUSIONS: The IHHS-1 is a physical head surrogate that can produce repeatable data for the interpretation of inner structures behavior during multidirectional impacts with or without helmets of different characteristics.

Mental health professionals' attitudes toward patients with PTSD and depression.

BACKGROUND: To date, mental health professionals' attitudes toward posttraumatic stress disorder (PTSD), compared to other psychiatric disorders such as schizophrenia or depression, have rarely been studied. OBJECTIVE: We assessed mental health professionals' attitudes toward patients with PTSD compared to patients suffering from depression. METHOD: Case vignettes of a patient with either PTSD or depression were presented to two samples of mental health professionals: attendees of a conference on posttraumatic stress (N=226) or of a lecture for psychiatry residents (N=112). Participants subsequently completed a questionnaire that assessed their attitude reactions to the presented case. RESULTS: Participants showed similarly positive attitudes toward depression and PTSD. PTSD elicited a more favorable attitude with regard to prosocial reactions, estimated dependency, attributed responsibility, and interest in the case, particularly in mental health professionals specializing in psychotraumatology. Across diagnoses, higher age and longer professional experience were associated with more positive attitudes toward patients. CONCLUSIONS: Mental health professionals' positive attitudes toward patients with depression and PTSD correlate with their specific knowledge about the disorder, their level of professional training, and their years of professional experience. LIMITATIONS: The instruments used, although based on established theoretical concepts in attitude research, were not validated in their present versions.

Perceived responsibility for change as an outcome predictor in cognitive-behavioural group therapy.

PURPOSE: The study of control beliefs in psychotherapy research has been neglected in the past years. Based on the evidence that some patients do not benefit enough from therapy because of inadequate expectancies regarding the responsibility and the mechanisms of therapeutic change, assessing control beliefs specific to the psychotherapy context and linking them to therapy outcome can help highlighting this specific aspect and reactivating a neglected field of clinical research. METHOD: Using a new validated instrument (Questionnaire on Control Expectancies in Psychotherapy, TBK), this study investigated whether and how perceived responsibility for change predicts favourable response to group cognitive-behavioural therapy in a sample of 49 outpatients with social anxiety disorder (SAD). Patient engagement and therapy-related self-efficacy were assessed as possible process variables. RESULTS: Among therapy-related control beliefs, low powerful others expectancies (towards the therapist) were found to be the strongest predictor for clinical improvement at follow-up. At a process level, analyses of mediation showed that powerful others expectancies predicted therapy engagement, which then influenced the degree of clinical improvement on social anxiety levels and global symptoms. The association between therapy-specific internality and outcome was confirmed for social anxiety at follow-up and was partially mediated by therapy-related self-efficacy. CONCLUSIONS: Findings confirm that therapy-related control beliefs predict psychotherapy process (patient engagement and therapy-specific self-efficacy) and outcome in cognitive-behavioural group therapy for SAD. Implications for clinicians and for future research are discussed.

1-mJ Q-switched diode-pumped Nd:BaY(2)F(8) laser.

We report what is to our knowledge the first high repetition rate Q-switched Nd:BaY(2)F(8) (Nd:BaYF) laser pumped with a multiwatt fiber-coupled diode array tuned at 806 nm. As much as 2.42 W of average power and up to 1.05 mJ of pulse energy were obtained with 6.1 W of absorbed pump power, with excellent beam quality (M(2)<1.2) and linear polarization.