Higher-order Kerr terms allow ionization-free filamentation in gases

We show that higher-order nonlinear indices ($n_4$, $n_6$, $n_8$, $n_{10}$) provide the main defocusing contribution to self-channeling of ultrashort laser pulses in air and Argon at 800 nm, in contrast with the previously accepted mechanism of filamentation where plasma was considered as the dominant defocusing process. Their consideration allows to reproduce experimentally observed intensities and plasma densities in self-guided filaments.Comment: 11 pages, 6 figures (11 panels

Implant surfaces exposed to the oral cavity and treated with toothpaste containing oxygen releasing compound : a morphological controlled clinical trial

Aim of the present in vivo study is to assess if a toothpaste containing an oxygen releasing compound (AX) is able to reduce the biofilm formation on implants with rough surface compared to a control toothpaste, without affecting the microstructure of the tested surface. Methods: In this double blind, cross-over, controlled clinical trial, a total of fourteen healthy volunteers were recruited. For each subject, two mandibular splints (test and control) were created with one implant fixed on the right lingual side of the mandibular arch. The splint was continuously worn for 5 days and the daily hygiene was performed wearing the splint and using the test (AX) or control toothpaste. Implants were analyzed at scanning-electron-microscopy and at laser profilometer for the assessment of biofilm adhesion (% of areas free from biofilm-FA) and surface changes (morphology and roughness). Results: FA resulted significantly higher in test than in control implants. No differences were found between groups in term of biofilm organization, surface microstructure and roughness. Discussion: Daily use of toothpaste containing AX seems to reduce the amount of biofilm adherent to the rough implant surface without corrosion or degradation of the titanium surface

Histomorphometrical evaluation of the effects of Aminogam® gel in oral healing process of post-surgical soft tissue

Wound healing is a dynamic process that involves a complex interaction of inflammatory cells, cytokines and mediators of extracellular matrix [1]. One of the processes that occur during tissue regeneration is angiogenesis and it is considered to have a pivotal role in wound repair. Previous studies have shown that a topical application of proteins and sodium hyaluronate to wounds can expedite the repair of damaged tissue [2]. The aim of this preliminary study is to evaluate the efficacy of Aminogam\uae gel (A\uae) (ErreKappa Euroterapici SpA, Milano), a topical medication which contains 4 amino acids (glycine, leucine, proline, lysine) and sodium hyaluronate, used to improve and accelerate gingival flap healing following molar extraction by analyzing collagen fibers amount, orientation and microvascular distribution (MVD). Ten patients (mean age 49ys) were included in the study. Two teeth (38 and 48) were extracted at an interval of 30 days. The \u201ctest\u201d site (AM) was treated with A\uae while the \u201ccontrol\u201d site (no AM) was not. Dental extraction was performed and the flaps were sutured with a consequent excess of tissue for histological processing (T0). A\uae had been applied only at the AM site for 10 days post-extraction. At suture removal, a gingivoplasty was performed and the exceeding tissue was histologically analysed (T1). Paraffin blocks were cut and slides were stained with haematoxylin-eosin and Sirius Red. No signs of inflammatory infiltrate or necrosis were observed. Sirius Red staining highlighted a lower degree of organized collagen fibers at T1 vs T0. At T0 the fibers were organized in closely packed and well-oriented bundles. At T1-no AM fibers were thin and formed a disorganized grid. At T1-AM fibers appeared thicker and the tissue appeared more mature compared to T1-no AM. Immunohistochemistry against CD31 was performed to mark endothelial cells and to calculate MVD by stereological method [3]. MVD resulted highest at T1-AM. The T1 data normalized on T0 presented a statistically significant difference (p=0.012) between AM and no AM group. In conclusion, A\uae gel seems to increase new blood vessels formation and to promote collagen deposition and organization. References [1] Gurtner et al. Nature. 2008;453(7193):314-21. [2] Zhu et al. BMC Oral Health. 2015;15:60. [3] Canullo et al. J Clin Periodontol. 2016;38:86-94

Childhood loneliness as a predictor of adolescent depressive symptoms: an 8-year longitudinal study

Childhood loneliness is characterised by children’s perceived dissatisfaction with aspects of their social relationships. This 8-year prospective study investigates whether loneliness in childhood predicts depressive symptoms in adolescence, controlling for early childhood indicators of emotional problems and a sociometric measure of peer social preference. 296 children were tested in the infant years of primary school (T1 5 years of age), in the upper primary school (T2 9 years of age) and in secondary school (T3 13 years of age). At T1, children completed the loneliness assessment and sociometric interview. Their teachers completed externalisation and internalisation rating scales for each child. At T2, children completed a loneliness assessment, a measure of depressive symptoms, and the sociometric interview. At T3, children completed the depressive symptom assessment. An SEM analysis showed that depressive symptoms in early adolescence (age 13) were predicted by reports of depressive symptoms at age 8, which were themselves predicted by internalisation in the infant school (5 years). The interactive effect of loneliness at 5 and 9, indicative of prolonged loneliness in childhood, also predicted depressive symptoms at age 13. Parent and peer-related loneliness at age 5 and 9, peer acceptance variables, and duration of parent loneliness did not predict depression. Our results suggest that enduring peer-related loneliness during childhood constitutes an interpersonal stressor that predisposes children to adolescent depressive symptoms. Possible mediators are discussed

On negative higher-order Kerr effect and filamentation

As a contribution to the ongoing controversy about the role of higher-order Kerr effect (HOKE) in laser filamentation, we first provide thorough details about the protocol that has been employed to infer the HOKE indices from the experiment. Next, we discuss potential sources of artifact in the experimental measurements of these terms and show that neither the value of the observed birefringence, nor its inversion, nor the intensity at which it is observed, appear to be flawed. Furthermore, we argue that, independently on our values, the principle of including HOKE is straightforward. Due to the different temporal and spectral dynamics, the respective efficiency of defocusing by the plasma and by the HOKE is expected to depend substantially on both incident wavelength and pulse duration. The discussion should therefore focus on defining the conditions where each filamentation regime dominates.Comment: 22 pages, 11 figures. Submitted to Laser physics as proceedings of the Laser Physics 2010 conferenc

Hydrophobic and ionic-interactions in bulk and confined water with implications for collapse and folding of proteins

Water and water-mediated interactions determine thermodynamic and kinetics of protein folding, protein aggregation and self-assembly in confined spaces. To obtain insights into the role of water in the context of folding problems, we describe computer simulations of a few related model systems. The dynamics of collapse of eicosane shows that upon expulsion of water the linear hydrocarbon chain adopts an ordered helical hairpin structure with 1.5 turns. The structure of dimer of eicosane molecules has two well ordered helical hairpins that are stacked perpendicular to each other. As a prelude to studying folding in confined spaces we used simulations to understand changes in hydrophobic and ionic interactions in nano droplets. Solvation of hydrophobic and charged species change drastically in nano water droplets. Hydrophobic species are localized at the boundary. The tendency of ions to be at the boundary where water density is low increases as the charge density decreases. Interaction between hydrophobic, polar, and charged residue are also profoundly altered in confined spaces. Using the results of computer simulations and accounting for loss of chain entropy upon confinement we argue and then demonstrate, using simulations in explicit water, that ordered states of generic amphiphilic peptide sequences should be stabilized in cylindrical nanopores

Behavioral inhibition in childhood predicts smaller hippocampal volume in adolescent offspring of parents with panic disorder

Behavioral inhibition (BI) is a genetically influenced behavioral profile seen in 15–20% of 2-year-old children. Children with BI are timid with people, objects and situations that are novel or unfamiliar, and are more reactive physiologically to these challenges as evidenced by higher heart rate, pupillary dilation, vocal cord tension and higher levels of cortisol. BI predisposes to the later development of anxiety, depression and substance abuse. Reduced hippocampal volumes have been observed in anxiety disorders, depression and posttraumatic stress disorder. Animal models have demonstrated that chronic stress can damage the hippocampal formation and implicated cortisol in these effects. We, therefore, hypothesized that the hippocampi of late adolescents who had been behaviorally inhibited as children would be smaller compared with those who had not been inhibited. Hippocampal volume was measured with high-resolution structural magnetic resonance imaging in 43 females and 40 males at 17 years of age who were determined to be BI+ or BI− based on behaviors observed in the laboratory as young children. BI in childhood predicted reduced hippocampal volumes in the adolescents who were offspring of parents with panic disorder, or panic disorder with comorbid major depression. We discuss genetic and environmental factors emanating from both child and parent that may explain these findings. To the best of our knowledge, this is the first study to demonstrate a relationship between the most extensively studied form of temperamentally based human trait anxiety, BI, and hippocampal structure. The reduction in hippocampal volume, as reported by us, suggests a role for the hippocampus in human trait anxiety and anxiety disorder that warrants further investigation