725 research outputs found

    Shannon entropies of atomic structure factors, off-diagonal order and electron correlation

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    Shannon entropies of one- and two-electron atomic structure factors in the position and momentum representations are used to examine the behavior of the off-diagonal elements of density matrices with respect to the uncertainty principle and to analyze the effects of electron correlation on off-diagonal order. We show that electron correlation induces off-diagonal order in position space which is characterized by larger entropic values. Electron correlation in momentum space is characterized by smaller entropic values as information is forced into regions closer to the diagonal. Related off-diagonal correlation functions are also discussed

    Prediction of the slope discontinuity in stress-strain behaviour of polymeric composites with spherical inclusions

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    The estimation of the point of discontinuity in the slope of stress-strain curves (commonly referred to as "knee") generally observed with composite polymeric materials could be an important problem for the specific application of the composite items. In this work, we have used the results from classical elasticity theory to calculate the residual thermal stresses and proposed simplifying assumptions to calculate a "lower bound" on the applied stress value at which the "knee" can occur. The theoretical predictions have been then compared with the experimental data on various polymeric composites containing glass beads and the agreement is found to be very sound. The proposed equation can be reliably used in engineering design

    In Vitro Comparative Biocompatibility Testing of Carbofilm Coated and Uncoated Polyetherimide for Cardiovascular Application

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    When blood contacts the surface of a material, several processes take place including the activation of coagulation and immune systems. The aim of this work is to study in vitro the biological reactions seen from the point of view of hemocompatibility and cytocompatibility of a new polymer suggested as an artificial surface for cardiovascular applications: Carbofilm® coated polyetherimide (C®PEI) in comparison to polyetherimide (PEI), the uncoated form. PEI and C®PEI showed no signs of acute cytotoxicity although following long term incubation with PEI cytotoxicity was somewhat increased; both materials supported good endothelial cell adhesion with a higher level of cell proliferation on the coated form. No significant difference was detected in the activation of the inflammatory response and in thrombogenicity tested by assay of prostaglandin E2 (PGE2) and tromboxane B2 (TXB2) respectively, following incubation of the biomaterials with platelet-rich plasma (PRP). Complement activation assessed by sodium dodecyl sulfate - polyacrylamide gel electrophoresis (SDS-PAGE)/Western Blot analysis of both contacting plasma and protein which adsorbed on the surface of the polymers showed both materials to be activators of complement. In conclusion, Carbofilm® coating, showing lower cytotoxic activity and higher endothelial cell growth in comparison with uncoated material, seems to increase PEI compatibility

    The mediation of care and overprotection between parent-adolescent conflicts and adolescents’ psychological difficulties during the pandemic: which role for fathers?

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    Background: There is evidence of a significant raise in youths’ emotional and behavioral difficulties during the pandemic. Only a few studies have addressed parent-adolescent conflict, and none investigated the possible mediating effect of parenting in the association between conflicts with parents and adolescents’ symptoms. This study aimed at investigating youths’ psychological symptoms during the pandemic, focusing on the predicting effect of parent-adolescent conflict. The mediating role of care and overprotection was also explored, considering whether adolescent gender moderated this mediation. Methods: 195 adolescents aged 14–18 years participated in an online longitudinal study. Perceived conflict with parents and parenting dimensions (Parental Bonding Instrument; PBI) were assessed at baseline (2021). Self-reported psychological difficulties (Strengths and Difficulties Questionnaire; SDQ) were collected at baseline and after one year (2022). Results: A significantly severer symptomatology was found in adolescents having a conflictual relationship with one or both parents. Major conflicts with parents correlated with lower care and greater overprotection in mothers and fathers. However, parental overprotection and maternal care were not mediators of the relationship between conflict and youths' difficulties. The only exception was represented by paternal care that fully mediated this relationship in both adolescent males and females. Conclusions: Although further investigations are needed to overcome limitations due to the small sample, findings extend our insight into the impact of parent-adolescent conflict, highlighting the role of fathers’ care and the need to maximize their involvement in clinical interventions

    Geologic and mineral and water resources investigations in western Colorado using ERTS-1 data

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    The author has identified the following significant results. Topography was found to be the most important factor defining folds on ERTS-1 imagery of northwestern Colorado; tonal variations caused by rock reflectance and vegetation type and density are the next most important factors. Photo-linears mapped on ERTS-1 imagery of central Colorado correlate well with ground-measured joint and fracture trends. In addition, photo-linears have been successfully used to determine the location and distribution of metallic mineral deposits in the Colorado Mineral Belt. True color composites are best for general geologic analysis and false color composites prepared with positive/negative masks are useful for enhancing local geologic phenomena. During geologic analysis of any given area, ERTS-1 imagery from several different dates should be studied

    Neural processing of emotions in traumatized children treated with eye movement desensitization and reprocessing therapy: a hdEEG study

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    Eye Movement Desensitization and Reprocessing (EMDR) therapy has been proven efficacious in restoring affective regulation in Post-Traumatic Stress Disorder (PTSD) patients. However, its effectiveness on emotion processing in children with complex trauma has yet to be explored. High density Electroencephalography (hdEEG) was used to investigate the effects of EMDR on brain responses to adults\u27 emotions on children with histories of early maltreatment. Ten school-aged children were examined before (T0) and within one month after the conclusion of EMDR (T1). hdEEGs were recorded while children passively viewed angry, afraid, happy, and neutral faces. Clinical scales were administered at the same time. Correlation analyses were performed to detect brain regions whose activity was linked to children\u27s traumatic symptom-related and emotional-adaptive problem scores. In all four conditions, hdEEG showed similar significantly higher activity on the right medial prefrontal and fronto-temporal limbic regions at T0, shifting towards the left medial and superior temporal regions at T1. Moreover, significant correlations were found between clinical scales and the same regions whose activity significantly differed between pre- and post-treatment. These preliminary results demonstrate that, after EMDR, children suffering from complex trauma show increased activity in areas implicated in high-order cognitive processing when passively viewing pictures of emotional expressions. These changes are associated with the decrease of depressive and traumatic symptoms, and with the improvement of emotional-adaptive functioning over time

    Bioactive and resorbable soybean-based biomaterials

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    A method of producing a soybean-based biomaterial which is suitable for use in a biomedical product, the method comprising: defatting soy flour; either prior to or at the same time as, performing a solvent extraction; to produce a biomaterial comprising variable levels of soy proteins, carbohydrates and isoflavones. The resulting biomaterials have a range of biomedical uses and are particularly desirable because of their isoflavone content. Examples of biomedical products containing the biomaterials include wound dressings; scaffolds for tissue engineering; fillers or implants for use in surgery; temporary barriers for use in dental or surgical procedures or to prevent post-surgical tissue adherence; carriers for the delivery of drugs, bioactive peptides or plasmids; anti-inflammatory agents; coatings for wound dressings or for dental, medical, surgical or veterinary devices or implants; and compositions for soothing skin or gum irritation

    Nutritional characterization of Cicer arietinum L. cultivars with respect to morphological and agronomic parameters

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    Chickpea (Cicer arietinum L.) is one of the grain legumes more interesting for its nutritional value and genetic improvement in order to resistance to Aschochyta rabiei, seeds weight and adaptation to mechanical harvesting. The aim of this research was the agronomic and qualitative characterization of 15 cultivars of chickpea. During the cultural cycle resistance and sensitiveness to Aschochyta rabiei were analyzed. At harvesting, grain yield and yields components were registered. Moreover, proximate composition, fatty acids content and saturated/unsaturated ratio of grain samples were determined. Cultivars with high 1000 seeds weight showed a more favourable oleic acid content and unsaturated/saturated ratio but those with smooth seeds had a higher content in linolenic acid. All cultivars showed high values of polyunsaturated fatty acids (42.9-56.2%), inferior of monounsaturated (29.5-36.1%) and low of saturated (10.0-22.9%). Black chickpea (2.9) had the lowest unsaturated/saturated ratio, while the highest was noticed for cv. Visir (7.46). Cultivars with small and smooth seeds showed a better proteins content. These results showed availability of seeds with favourable characteristics useful for different utilization. In particular, the cultivars with small and smooth seeds, usually not preferred by consumers, seem to be interesting for processing in nutritional foods and dietetics
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