Publications by authors named "Theodorakis P"

Self-cleaning applications based on bionic surface designs requires an in-depth understanding of unique and complex wetting and evaporation processes of sessile droplets on natural biosurfaces. To this end, hydrophobic bamboo and Kalanchoe blossfeldiana leaves are excellent candidates for self-cleaning applications, but various properties, such as the heat and mass transfer processes during evaporation, remain unknown. Here, the dynamics of contact angle, radius, and heat and mass transfer during evaporation of sessile droplets on bamboo and Kalanchoe blossfeldiana leaves with roughness in the range 2.

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Background: Certain causes of death can be avoided with access to timely prevention and treatment. We quantified trends in avoidable deaths from cardiovascular diseases for European Union (EU) countries from 1995 to 2020 and examined variations by demographics, disease characteristics, and geography.

Methods: Retrospective secondary data analysis of avoidable cardiovascular mortality using the WHO Mortality Database.

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The self-sustained motion of fluids on gradient substrates is a spectacular phenomenon, which can be employed and controlled in applications by carefully engineering the substrate properties. Here, we report on a design of a gel substrate with stiffness gradient, which can cause the spontaneous motion of a droplet along (durotaxis) or to the opposite (antidurotaxis) direction of the gradient, depending on the droplet affinity to the substrate. By using extensive molecular dynamics simulations of a coarse-grained model, we find that the mechanisms of the durotaxis and antidurotaxis droplet motion are distinct, require the minimization of the interfacial energy between the droplet and the substrate, and share similarities with those mechanisms previously observed for brush substrates with stiffness gradient.

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Protein misfolding, aggregation, and fibril formation play a central role in the development of severe neurological disorders, including Alzheimer's and Parkinson's diseases. The structural stability of mature fibrils in these diseases is of great importance, as organisms struggle to effectively eliminate amyloid plaques. To address this issue, it is crucial to investigate the early stages of fibril formation when monomers aggregate into small, toxic, and soluble oligomers.

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Background: The COVID-19 pandemic has brought significant mental health challenges, particularly for vulnerable populations, including non-binary gender individuals. The COMET international study aimed to investigate specific risk factors for clinical depression or distress during the pandemic, also in these special populations.

Methods: Chi-square tests were used for initial screening to select only those variables which would show an initial significance.

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Article Synopsis
  • Droplet evaporation on rough substrates is critical for applications like cooling and micro/nanoparticle assembly, but understanding this process solely through macroscopic studies is challenging due to its complexity.
  • Molecular dynamics simulations were used to analyze droplet evaporation on hydrophilic substrates with varying roughness (0.1, 0.15, and 0.2 μm), comparing results with relevant experiments to better understand the mechanisms involved.
  • The study found that while macroscale droplets exhibited a stable evaporation mode regardless of roughness, nanoscale droplets showed a shift in evaporation modes with increasing roughness, highlighting the significant influence of scale on the evaporation dynamics and heat transfer efficiency on rough substrates.
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The transport of water and protons in the cathode catalyst layer (CCL) of proton exchange membrane (PEM) fuel cells is critical for cell performance, but the underlying mechanism is still unclear. Herein, the ionomer structure and the distribution/transport characteristics of water and protons in CCLs are investigated via all-atom molecular dynamics simulations. The results show that at low water contents, isolated water clusters form in ionomer pores, while proton transport is mainly via the charged sites of the ionomer side chains and the Grotthuss mechanism.

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Background: The prevalence of medical illnesses is high among patients with psychiatric disorders. The current study aimed to investigate multi-comorbidity in patients with psychiatric disorders in comparison to the general population. Secondary aims were to investigate factors associated with metabolic syndrome and treatment appropriateness of mental disorders.

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Computer simulation is an important tool for scientific progress, especially when lab experiments are either extremely costly and difficult or lack the required resolution. However, all of the simulation methods come with limitations. In molecular dynamics (MD) simulation, the length and time scales that can be captured are limited, while computational fluid dynamics (CFD) methods are built on a range of assumptions, from the continuum hypothesis itself, to a variety of closure assumptions.

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We investigate the coalescence of surfactant-laden water droplets by using several different surfactant types and a wide range of concentrations by means of a coarse-grained model obtained by the statistical associating fluid theory. Our results demonstrate in detail a universal mass transport mechanism of surfactant across many concentrations and several surfactant types during the process. Coalescence initiation is seen to occur a single pinch due to aggregation of surface surfactant, and its remnants tend to become engulfed in part inside the forming bridge.

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Durotaxis motion is a spectacular phenomenon manifesting itself by the autonomous motion of a nano-object between parts of a substrate with different stiffness. This motion usually takes place along a stiffness gradient from softer to stiffer parts of the substrate. Here, we propose a new design of a polymer brush substrate that demonstrates antidurotaxis droplet motion, that is, droplet motion from stiffer to softer parts of the substrate.

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Objectives: The economic crisis and the resulting austerity in Greece led to a drastic reduction in healthcare spending, which has been assumed to have impacted people's health. This paper discusses official standardized mortality rates in Greece between 2000 and 2015.

Methods: This study was designed to analyze population-level data and collected data from the World Bank, the Organisation for Economic Co-operation and Development, Eurostat, and the Hellenic Statistics Authority.

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Using extensive molecular dynamics simulation of a coarse-grained model, we demonstrate the possibility of sustained unidirectional motion (durotaxis) of droplets without external energy supply when placed on a polymer brush substrate with stiffness gradient in a certain direction. The governing key parameters for the specific substrate design studied, which determine the durotaxis efficiency, are found to be the grafting density of the brush and the droplet adhesion to the brush surface, whereas the strength of the stiffness gradient, the viscosity of the droplet, or the length of the polymer chains of the brush have only a minor effect on the process. It is shown that this durotaxial motion is driven by the steady increase of the interfacial energy between droplet and brush as the droplet moves from softer to stiffer parts of the substrate whereby the mean driving force gradually declines with decreasing roughness of the brush surface.

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As one of the most fascinating confined water/ice phenomena, two-dimensional square ice has been extensively studied and experimentally confirmed in recent years. Apart from the unidirectional homogeneous square icing patterns considered in previous studies, the multidirectional partitioned square icing patterns are discovered in this study and characterized by molecular dynamics (MD) simulations. Square icing parameters are proposed to quantitatively distinguish the partitioned patterns from the homogeneous patterns and the liquid water.

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Background: Wearing facemasks is of proven efficacy as a public health protective measure against COVID-19. Currently there are no observational data concerning the wearing of facemasks and the adherence to guidelines concerning their handling.

Methods: Registration of the way passers-by were wearing facemasks at 26 different locations of five major cities in Greece.

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Introduction: The aim of the study was to investigate mental health and conspiracy theory beliefs concerning COVID-19 among health care professionals (HCPs).

Material And Methods: During lockdown, an online questionnaire gathered data from 507 HCPs (432 females aged 33.86 ± 8.

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Article Synopsis
  • A large international study involving 55,589 participants from 40 countries was conducted to assess the impact of COVID-19 on mental health, revealing that 17.80% of participants experienced probable depression and 16.71% reported distress.
  • The research indicated that individuals with a history of mental disorders showed significantly higher rates of depression, with the highest risk linked to conditions like Bipolar disorder and self-harm, and found that belief in conspiracy theories was prevalent among participants.
  • The study developed a model demonstrating the connection between anxiety, distress, and the progression to probable depression and suicidality, suggesting that addressing modifiable factors could be beneficial in improving mental health outcomes.
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Unlabelled: Policy Points The 2018 Declaration of Astana reemphasized the importance of primary health care and its role in achieving universal health coverage. While there is a large amount of literature on the economic aspects of delivering primary care services, there is a need for more comprehensive overviews of this evidence. In this article, we offer such an overview.

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Droplet nucleation and evaporation are ubiquitous in nature and many technological applications, such as phase-change cooling and boiling heat transfer. So far, the description of these phenomena at the molecular scale has posed challenges for modelling with most of the models being implemented on a lattice. Here, we propose an off-lattice Monte-Carlo approach combined with a grid that can be used for the investigation of droplet formation and evaporation.

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Pinning of liquid droplets on solid substrates is ubiquitous and plays an essential role in many applications, especially in various areas such as microfluidics and biology. Although pinning can often reduce the efficiency of various applications, a deeper understanding of this phenomenon can actually offer possibilities for technological exploitation. Here, by means of molecular dynamics simulation, we identify the conditions that lead to droplet pinning or depinning and discuss the effects of key parameters in detail, such as the height of the physical pinning barrier and the wettability of the substrates.

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