Design, Calibration, and Application of a Robust, Cost-Effective, and High-Resolution Lensless Holographic Microscope

Lensless holographic microscope (LHM) is an emerging very promising technology that provides high-quality imaging and analysis of biological samples without utilizing any lens for imaging. Due to its small size and reduced price, LHM can be a very useful tool for the point-of-care diagnosis of diseases, sperm assessment, or microfluidics, among others, not only employed in advanced laboratories but also in poor and/or remote areas. Recently, several LHMs have been reported in the literature. However, complete characterization of their optical parameters remains not much presented yet. Hence, we present a complete analysis of the performance of a compact, reduced cost, and high-resolution LHM. In particular, optical parameters such as lateral and axial resolutions, lateral magnification, and field of view are discussed into detail, comparing the experimental results with the expected theoretical values for different layout configurations. We use high-resolution amplitude and phase test targets and several microbeads to characterize the proposed microscope. This characterization is used to define a balanced and matched setup showing a good compromise between the involved parameters. Finally, such a microscope is utilized for visualization of static, as well as dynamic biosamples.

Phase Properties of Different HfO2 Polymorphs: A DFT-Based Study

Background: Hafnium Dioxide (HfO2) represents a hopeful material for gate dielectric thin films in the field of semiconductor integrated circuits. For HfO2, several crystal structures are possible, with different properties which can be difficult to describe in detail from an experimental point of view. In this study, a detailed computational approach has been shown to present a complete analysis of four HfO2 polymorphs, outlining the intrinsic properties of each phase on the basis of atomistic displacements. Methods: Density functional theory (DFT) based methods have been used to accurately describe the chemical physical properties of the polymorphs. Corrective Hubbard (U) semi-empirical terms have been added to exchange correlation energy in order to better reproduce the excited-state properties of HfO2 polymorphs. Results: the monoclinic phase resulted in the lowest cohesive energy, while the orthorhombic showed peculiar properties due to its intrinsic ferroelectric behavior. DFT + U methods showed the different responses of the four polymorphs to an applied field, and the orthorhombic phase was the least likely to undergo point defects as oxygen vacancies. Conclusions: The obtained results give a deeper insight into the differences in excited states phenomena in relation to each specific HfO2 polymorph.

An Analysis of Two Fluid Layers Enclosed Between Two Non-Porous Surfaces

The stability of a two-phase interface is a crucial occurrence that involves the design of many engineering applications. It correlates the spatial and droplet size-distributions of many fluid spraying applications and has a great effect on the estimations of the critical heat flux of systems that involves phase change or evaporation. However, the existing hydrodynamic models are only able to predict the stability of a plane fluid sheet, surrounded by an infinite pool of liquid. The case of a thin sheet of liquid surrounding a vapor sheet and enclosed between two walls has not been studied yet. The present paper solves this problem using a linearized stability analysis. Velocity potentials satisfying these conditions are introduced and a complete analysis is presented.

Information technologies of teaching in a secondary school

The conference participants are offered components of the educational and methodological complex in physics, which are obtained not by advanced pedagogical experience, ie by trial and error, but by detailed and complete analysis and calculation of structures and algorithms of the educational process in secondary school and its individual components. It is a guide for students, systematization of educational information, algorithm for solving physical problems, solving standard physical problems on a computer, diagnosing student performance and rating assessment of knowledge.

Techniques and Trends Towards Various Dimensions of Robust Security Testing in Global Software Engineering

With the growth of software vulnerabilities, the demand for security integration is increasingly necessary to more effectively achieve the goal of secure software development globally. Different practices are used to keep the software intact. These practices should also be examined to obtain better results depending on the level of security. The security of a software program device is a characteristic that permeates the whole system. To resolve safety issues in a software program security solutions have to be implemented continually throughout each web page. The motive of this study is to offer a complete analysis of safety, wherein protection testing strategies and equipment can be categorized into: technical evaluation strategies and non-technical assessment strategies. This study presents high-level ideas in an easy form that would help professionals and researchers solve software security testing problems around the world. One way to achieve these goals is to separate security issues from other enforcement issues so that they can be resolved independently and applied globally.

Chemical Composition of Green Pea (Pisum sativum L.) Pods Extracts and Their Potential Exploitation as Ingredients in Nutraceutical Formulations

Agro-industrial wastes contain a large number of important active compounds which can justify their use as innovative ingredients in nutraceutical products. This study aimed to provide a complete analysis of active molecules, namely (poly)phenols in pea pods water-based extracts, through a UHPLC-Q-Orbitrap HRMS methodology. Data showed that 5-caffeoylquinic acid, epicatechin, and hesperidin were the most relevant (poly)phenols found in the assayed extracts, with a mean value of 59.87, 29.46, and 19.94 mg/100 g, respectively. Furthermore, changes in antioxidant capacity and bioaccessibility of total phenolic compounds (TPC) after the simulated gastrointestinal (GI) process were performed using spectrophotometric assays (FRAP, DPPH, ABTS, and TPC by Folin-Ciocalteu). The acid-resistant capsules (ARC) and the non-acid resistant capsules (NARC) containing the pea pod extract underwent simulated GI digestion. The results suggested that the ARC formulations were able to preserve the active compounds along the simulated GI process, highlighting a higher TPC value and antioxidant capacity than the NARC formulations and the not-encapsulated extracts. Hence, the pea pods water-based extracts could be utilized as a potential alternative source of active compounds, and the use of ARC could represent a suitable nutraceutical formulation to vehiculate the active compounds, protecting the chemical and bioactive properties of (poly)phenols.

Large variation in availability of Maya food plant sources during ancient droughts

Paleoclimatic evidence indicating a series of droughts in the Yucatan Peninsula during the Terminal Classic period suggests that climate change may have contributed to the disruption or collapse of Classic Maya polities. Although climate change cannot fully account for the multifaceted, political turmoil of the period, it is clear that droughts of strong magnitude could have limited food availability, potentially causing famine, migration, and societal decline. Maize was undoubtedly an important staple food of the ancient Maya, but a complete analysis of other food resources that would have been available during drought remains unresolved. Here, we assess drought resistance of all 497 indigenous food plant species documented in ethnographic, ethnobotanical, and botanical studies as having been used by the lowland Maya and classify the availability of these plant species and their edible components under various drought scenarios. Our analysis indicates availability of 83% of food plant species in short-term drought, but this percentage drops to 22% of food plant species available in moderate drought up to 1 y. During extreme drought, lasting several years, our analysis indicates availability of 11% of food plant species. Our results demonstrate a greater diversity of food sources beyond maize that would have been available to the Maya during climate disruption of the Terminal Classic period than has been previously acknowledged. While drought would have necessitated shifts in dietary patterns, the range of physiological drought responses for the available food plants would have allowed a continuing food supply under all but the most dire conditions.

Comparison of the Characteristics and Outcomes of SARS-COV 2 Critically Ill Patients After Emergence of the Variant of Concern 20H/501Y.V2: A Comparative Cohort Study

BackgroundThere are currently no data regarding characteristics of critically ill patients with SARS-CoV-2 Variant of Concern (VOC) 20H/501Y.V2. We therefore aimed to describe changes of characteristics in critically ill patients with Covid-19 between the first and the second wave when viral genome sequencing indicated that VOC was largely dominant in Mayotte Island (Indian Ocean).MethodsConsecutive patients with Covid-19 and over 18 years admitted in the unique Intensive Care Unit (ICU) of Mayotte during wave 2 were compared with an historical cohort of patients admitted during wave 1. We performed a Logistic Regression (LR) comparing wave 1 and wave 2 as outcomes. To complete analysis of changes in characteristics and outcomes, we built a Random Forest model (RF) -i.e., a machine learning classification tool- using the same variable set as that of the LR.ResultsWe included 156 patients, 41 (26.3%) and 115 (73.7%) belonging to the first and second waves respectively. Univariate analysis did not find difference in demographic data or in mortality. Our multivariate LR found that patients in wave 2 had less fever (absence of fever aOR 5.23, 95% CI 1.89 – 14.48, p=0.001) and a lower SAPS II (aOR 0.95, 95% CI 0.91 – 0.99, p=0.007) at admission; at 24 hours, the need of invasive mechanical ventilation was higher (aOR 3.49, 95% CI 0.98 – 12.51, p=0.055) and pO2/FiO2 ratio was lower (aOR 0.99, 95 % CI 0.98-0.99, p=0.03). Patients in wave 2 had also an increased risk of VAP (aOR 4.64, 95% CI 1.54-13.93, p=0.006). Occurrence of VAP was also a key variable to classify patients between wave 1 and wave 2 in the variable importance plot of the RF model.ConclusionOur data suggested that VOC 20H/501Y.V2 could be associated with a higher severity of respiratory failure at admission and a higher risk for developing VAP. We hypothesized that the expected gain in survival brought by recent improvements in critical care management could have been mitigated by increased transmissibility of the new lineage leading to admission of more severe patients. The immunological role of VOC 20H/501Y.V2 in the propensity for VAP requires further investigations.

An Attempt to Assess the Impact of Pandemic Restrictions on the Lifestyle, Diet, and Body Mass Index of Children with Endocrine Diseases—Preliminary Results

Background: Home isolation during the coronavirus 2019 (COVID-19) pandemic lockdown strongly impacted everyday life, affecting, in particular, eating habits and everyday activity. The aim of this study was to analyze the impact of the pandemic on behaviors and subsequent changes in body mass index (BMI) in children from Southern Poland. Methods: The study included 206 participants (104 females and 102 males) with a complete analysis of 177 participants (96 females and 81 males) with a mean age of 12.8 ± 2.6 years admitted to three pediatric endocrinology clinics (Rzeszów, Kraków, and Katowice) due to simple obesity, type 1 diabetes mellitus, somatotropin pituitary deficiency on growth hormone replacement therapy, and other endocrine and metabolic disorders between June and September 2020. The study used a self-prepared questionnaire regarding eating habits, physical activity, screen time, and sleep before and during the lockdown. Anthropometric measurements were performed under clinical settings twice (before the pandemic in January–March 2020, and in June–September 2020). Results: During the lockdown, BMI z-scores increased over the whole group, especially in obese children (0.073 ± 0.18, p = 0.002). The number of children who declared low and high physical activity of more than 60 min per day declined from 41.2% and 18.6% to 31.1% and 6.2% (p = 0.03 and p < 0.001), respectively; sleep times over 8 h increased (46.9% vs. 60.4% p = 0.007); screen times over 5 h daily increased (14.7% to 46.9%, p < 0.001). Eating habits did not change significantly. Conclusions: Daily physical activity and sleep levels were affected by the pandemic leading to the increase of BMI, especially in obese patients with endocrine disorders. During the COVID-19 pandemic, forward-thinking strategies must be developed to prevent childhood obesity.