Biomimetic formation of CaCO3 particles showing single and hierarchical structures

The aim of this thesis was to study three biomimetic systems that imply the mineralization of calcium carbonate, CaCO3, an important biogenic mineral used by nature as an inorganic component in exoskeletons and tissues of many mineralising organisms. These systems can serve as models for the complex and often hardly accessible natural archetypes with the possibility to reveal principles of the complex hierarchical structure formation. Thus, the first system describes a possible influence of egg white lysozyme, an important protein which is present in the shell of eggs, on the precipitation of amorphous calcium carbonate (ACC) in vivo and its transition to calcite during eggshell calcification. The mineralization of the calcitic eggshell is simulated by starting from lysozyme-CaCl2-CO(OCH3)2-NaOH solution. A transformation to the final crystalline biomineral, calcite, is observed. This work may be also of general interest to understand protein-mineral interaction in the building of amorphous materials and their ageing. The second system contains the formation of hemispherical aragonite-vaterite microstructures formed in silicate-casein sols. The formed particles have a complex morphology and a hierarchical structure. The initiation of this mineralization process is due to the presence of silicate ions that interact with serine-monophosphate groups and modify the casein structure in aqueous solution and, as a consequence, promote crystal formation. This is an interesting system with a significant complexity, which is also often found in biominerals. The third system deals with the formation and the growth of novel curvilinear morphologies in inorganic composites containing crystalline aragonite and amorphous silica. These biomimetic morphologies show remarkable hierarchical structures with structural similarity to natural corals. The significance of this work is that the realm of biomorphs is shown to extend beyond the previously studied barium and strontium carbonates, to now include calcium carbonate. However, the helicoidal morphologies - the most outstanding features of barium or strontium carbonate silica biomorphs - were never achieved in this work. In an attempt to solve this task, we tried to seek answers to the following question: why calcium ions behave so differently from their homologue barium, in alkaline silica sols

Self-Reported Diurnal Preference and Sleep Disturbance in Type 2 Diabetes Mellitus

Background. Previous sleep studies suggest that type 2 diabetes mellitus is associated with poor quality of sleep and sleep disorders. Aim. To evaluate sleep parameters and diurnal preference in type 2 diabetic patients, using a questionnaire. Methods. Ninety seven patients (aged 55.8±8.3, sex ratio 1:1), previously diagnosed with type 2 diabetes mellitus, together with 102 controls (aged 47.1±10.5, sex ratio 1:1), without diabetes, completed a questionnaire containing the Romanian translation of the Composite Scale of Morningness, the Sleep Disorders Questionnaire, the Pittsburgh Sleep Quality Index, the Pittsburgh Insomnia Rating Scale, the Multidimensional Fatigue Inventory, the Epworth Sleepiness Scale, the Alcohol Use Disorders Identification Test and the Beck Depression Inventory II (BDI). The study was cross-sectional, as we included subjects from outpatient and inpatient facilities. The recruitment process was based on handing invitation letters to patients consulting their physician, as well as to their acquaintances, using the snowball sampling. Participation was voluntary and anonymous

Residents’ clinical empathy: gender and specialty comparisons - a Romanian study

Objective. To measure and examine medical residents’ (junior doctors) empathy and to compare psychiatry residents’ empathy with that of other specialties. Participants and Methods. A translated version of Jefferson Scale of Physician Empathy for Practising Health Professionals was administered to 112 Romanian residents. Results. 60 residents in psychiatry and 52 in other specialities completed the questionnaire. Statistically significant differences were found between male and female counterparts, and between psychiatrists and residents in other specialities. Conclusions. Male doctors seemed to be less empathic compared to female ones. Psychiatry was the most empathic medical specialty

Virtual Reality in Neurorehabilitation : An Umbrella Review of Meta-Analyses

Funding: This research received no external funding.Peer reviewedPublisher PD

Sleep Beliefs, Subjective Sleep Quality and Diurnal Preference – Findings from Depressed Patients

This study evaluated the relationship between dysfunctional sleep beliefs, circadian typology and self-reported sleep quality and insomnia. We assessed these parameters both in healthy controls and patients with depression. One hundred eighty six subjects were assessed and completed measures of sleep beliefs, sleep disturbance, sleep quality, daytime sleepiness, depressive symptoms and circadian typology. We found that sleep beliefs are slightly linked with the subjective sleep quality, but with neither the diurnal preference, nor the self-reported insomnia

The Effect of Learning in a Virtual Environment on Explicit and Implicit Memory by Applying a Process Dissociation Procedure

Virtual reality-based neuropsychological assessment has unique features that have the potential to increase the level of ecological validity of test results. Based on findings from the literature on the task difficulty of cognitive tasks embedded into virtual environments, we aimed to explore the task difficulty hypothesis of virtual reality in memory assessment. Our main objective was to test for differences or equivalences between performance on explicit and on implicit memory tasks in three learning environments: a computerized measure, a 3D desktop environment, and a 3D virtual environment. Seventy-seven healthy participants, aged between 19 and 39 years old, enrolled in the study and were randomly assigned to the learning conditions and responded to typical virtual reality measures. Outcomes of explicit and implicit memory resulted after applying Process Dissociation Procedure. One-way analysis of variance did not reveal a significant main effect of learning environment on explicit memory performance and equivalence testing showed similar performance on implicit memory across the learning conditions. In our study, both controlled and automatic memory processes were not influenced by the learning environment

Immersive virtual reality or computerised mindfulness meditation for improving mood? Preliminary efficacy from a pilot randomised trial

Introduction: Mindfulness interventions are effective in improving mood, reducing stress, and increasing quality of life. New developments in technology bring important channels to deliver mindfulness interventions that can increase accessibility, such as the Internet, computerised interventions, mobile apps and recently, virtual reality (VR). The aim of the present study is to enhance our current understanding of the use of VR in mindfulness, namely we examined in a pilot randomised trial the efficacy of an immersive VR-based mindfulness approach compared to an active control (computerised-based mindfulness meditation) on improving mood. A secondary objective was to examine whether VR use resulted in simulator sickness which could affect user engagement.Methods: Forty-seven (Mage = 29.22 years) healthy participants were randomly assigned to the experimental or control group.Results: A mixed 2X3 ANOVA showed a significant Time effect. Namely, negative emotions were reduced in both groups, with non-significant differences between groups. For positive emotions, on the other hand, our results showed no significant impact. Simulator sickness in VR was not present, according to t-test, making VR a safe delivery method.Discussion: Future research should investigate VR dosage and combine VR with other interventions (e.g., blended with face-to-face mindfulness interventions, with Internet-delivered interventions)

Virtual-reality-based attention assessment of ADHD: ClinicaVR: Classroom-CPT versus a traditional continuous performance test

Virtual-reality-based assessment may be a good alternative to classical or computerized neuropsychological assessment due to increased ecological validity. ClinicaVR: Classroom-CPT (VC) is a neuropsychological test embedded in virtual reality that is designed to assess attention deficits in children with attention deficit hyperactivity disorder (ADHD) or other conditions associated with impaired attention. The present study aimed to (1) investigate the diagnostic validity of VC in comparison to a traditional continuous performance test (CPT), (2) explore the task difficulty of VC, (3) address the effect of distractors on the performance of ADHD participants and typically-developing (TD) controls, and (4) compare the two measures on cognitive absorption. A total of 33 children diagnosed with ADHD and 42 TD children, aged between 7 and 13 years, participated in the study and were tested with a traditional CPT or with VC, along with several cognitive measures and an adapted version of the Cognitive Absorption Scale. A mixed multivariate analysis of covariance (MANCOVA) revealed that the children with ADHD performed worse on correct responses had more commissions and omissions errors than the TD children, as well as slower target reaction times . The results showed significant differences between performance in the virtual environment and the traditional computerized one, with longer reaction times in virtual reality. The data analysis highlighted the negative influence of auditory distractors on attention performance in the case of the children with ADHD, but not for the TD children. Finally, the two measures did not differ on the cognitive absorption perceived by the children

Efficacy and Moderators of Virtual Reality for Cognitive Training in People with Dementia and Mild Cognitive Impairment: A Systematic Review and Meta-Analysis

Background: Mild cognitive impairment (MCI) and dementia result in cognitive decline which can negatively impact everyday functional abilities and quality of life. Virtual reality (VR) interventions could benefit the cognitive abilities of people with MCI and dementia, but evidence is inconclusive. Objective: To investigate the efficacy of VR training on global and domain-specific cognition, activities of daily living and quality of life. To explore the influence of priori moderators (e.g., immersion type, training type) on the effects of VR training. Adverse effects of VR training were also considered. Methods: A systematic literature search was conducted on all major databases for randomized control trial studies. Two separate meta-analyses were performed on studies with people with MCI and dementia. Results: Sixteen studies with people with MCI and four studies with people with dementia were included in each meta-analysis. Results showed moderate to large effects of VR training on global cognition, attention, memory, and construction and motor performance in people with MCI. Immersion and training type were found to be significant moderators of the effect of VR training on global cognition. For people with dementia, results showed moderate to large improvements after VR training on global cognition, memory, and executive function, but a subgroup analysis was not possible. Conclusion: Our findings suggest that VR training is an effective treatment for both people with MCI and dementia. These results contribute to the establishment of practical guidelines for VR interventions for patients with cognitive decline