On Fluid Dynamics of Freshwater and Seawater in Marine Systems

Interaction between freshwater and seawater can significantly influence marine life and create important productive and dynamic natural habitats, such as estuaries. We study such processes and for this purpose we develop a new mathematical model with the system of coupled nonlinear conservation equations that govern the interaction of the two incompressible fluids with different properties. The system is solved by using implicit operator splitting and mixed finite elements methods. Finally, the numerical scheme has been used to provide simulations of two real world scenarios

Can models based on Artificial neural networks help predict the risk of fracture in osteoporotic patients?

Introduction: Osteoporosis is a systemic skeletal disorder characterized by low bone mass, leading to bone fragility, and consequent increase in fracture risk. Globally osteoporosis affects more than 200 million people, being the cause of more than 8.9 million fractures annually. Currently the most used diagnostic tool to predict 10-year probability of bone fracture risk is FRAX

Application of Linear and Nonlinear Heat Equation in Digital Image Processing

Istraživat ćemo primjenu parcijalnih diferencijalih jednadžbi u obradi digitalne slike. Primjenjujemo jednadžbu provođenja topline kako bismo na slici uklonili šum, istaknuli važne elemente i pripremili je za eventualnu daljnju obradu. Metodičkim slijedom dajemo teorijske značajke linearne difuzije, a zatim izvodimo jednostavne numeričke sheme temeljene na metodi konačnih razlika. Vođeni idejom očuvanja struktura na slici, primjerice rubova, u središnjem dijelu članka uvodimo Perona-Malikovu jednadžbu kao primjer nelinearne jednadžbe provođenja topline. Završavamo s usporedbom primjene linearne i nelinearne jednadžbe provođenja topline na testnim slikama.We will explore the application of partial differential equations on digital images. We will show how to use the heat equation to eliminate noise in an image, highlight important elements and prepare it for possible further processing. We also show known heat equation’s theoretical results in a methodical sequence and then derive simple numerical schemes based on the finite differences method. Guided by the idea of image structure preservation, for example edge preservation, the central part of this article introduces Perona-Malik equation as an example of a nonlinear heat equation. We conclude by comparing linear and nonlinear heat equation application on a couple of test images

Direct Identification of Urinary Tract Pathogens by MALDI-TOF/TOF Analysis and De Novo Peptide Sequencing

For mass spectrometry-based diagnostics of microorganisms, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is currently routinely used to identify urinary tract pathogens. However, it requires a lengthy culture step for accurate pathogen identification, and is limited by a relatively small number of available species in peptide spectral libraries (≤3329). Here, we propose a method for pathogen identification that overcomes the above limitations, and utilizes the MALDI-TOF/TOF MS instrument. Tandem mass spectra of the analyzed peptides were obtained by chemically activated fragmentation, which allowed mass spectrometry analysis in negative and positive ion modes. Peptide sequences were elucidated de novo, and aligned with the non- redundant National Center for Biotechnology Information Reference Sequence Database (NCBInr). For data analysis, we developed a custom program package that predicted peptide sequences from the negative and positive MS/MS spectra. The main advantage of this method over a conventional MALDI-TOF MS peptide analysis is identification in less than 24 h without a cultivation step. Compared to the limited identification with peptide spectra libraries, the NCBI database derived from genome sequencing currently contains 20, 917 bacterial species, and is constantly expanding. This paper presents an accurate method that is used to identify pathogens grown on agar plates, and those isolated directly from urine samples, with high accuracy

Fetal indusium griseum is a possible biomarker of the regularity of brain midline development in 3T MR imaging: A retrospective observational study

INTRODUCTION: This study aimed to assess the visibility of the indusium griseum (IG) in magnetic resonance (MR) scans of the human fetal brain and to evaluate its reliability as an imaging biomarker of the normality of brain midline development. MATERIAL AND METHODS: The retrospective observational study encompassed T2-w 3T MR images from 90 post-mortem fetal brains and immunohistochemical sections from 41 fetal brains (16-40 gestational weeks) without cerebral pathology. Three raters independently inspected and evaluated the visibility of IG in post-mortem and in vivo MR scans. Weighted kappa statistics and regression analysis were used to determine inter- and intra-rater agreement and the type and strength of the association of IG visibility with gestational age. RESULTS: The visibility of the IG was the highest between the 25 and 30 gestational week period, with a very good inter-rater variability (kappa 0.623-0.709) and excellent intra-rater variability (kappa 0.81-0.93). The immunochemical analysis of the histoarchitecture of IG discloses the expression of highly hydrated extracellular molecules in IG as the substrate of higher signal intensity and best visibility of IG during the mid-fetal period. CONCLUSIONS: The knowledge of developmental brain histology and fetal age allows us to predict the IG-visibility in magnetic resonance imaging (MRI) and use it as a biomarker to evaluate the morphogenesis of the brain midline. As a biomarker, IG is significant for post-mortem pathological examination by MRI. Therefore, in the clinical in vivo imaging examination, IG should be anticipated when an assessment of the brain midline structures is needed in mid-gestation, including corpus callosum thickness measurements

Navigating the shadows: medical professionals’ values and perspectives on end-of-life care within pediatric intensive care units in Croatia

Background and aimThis study explores healthcare professionals’ perspectives on end-of-life care in pediatric intensive care units (ICUs) in Croatia, aiming to illuminate their experiences with such practices, underlying attitudes, and major decision-making considerations. Amid the high variability, complexity, and emotional intensity of pediatric end-of-life decisions and practices, understanding these perspectives is crucial for improving care and policies.MethodsThe study utilized a cross-sectional survey intended for physicians and nurses across all pediatric ICUs in Croatia. It included healthcare professionals from six neonatal and four pediatric ICUs in total. As the data from neonatal and pediatric ICUs were examined jointly, the term pediatric ICU was used to denominate both types of ICUs. A statistical analysis was performed using Python and JASP, focusing on professional roles, professional experience, and regional differences.ResultsThe study included a total of 103 participants (with an overall response rate—in relation to the whole target population—of 48% for physicians and 29% for nurses). The survey revealed diverse attitudes toward and experiences with various aspects of end-of-life care, with a significant portion of healthcare professionals indicating infrequent involvement in life-sustaining treatment (LST) limitation discussions and decisions, as well as somewhat ambiguous attitudes regarding such practices. Notably, discrepancies emerged between different professional roles and, in particular, regions, underscoring the high variability of LST limitation-related procedures.ConclusionsThe findings highlight a pressing need for more straightforward guidelines, legal frameworks, support mechanisms, and communication strategies to navigate the complex terrain of rather burdensome end-of-life pediatric care, which is intrinsically loaded with profound ethical quandaries

Računalna analiza histoloških slika citoarhitektonike ljudske moždane kore

The structure of the cerebral cortex is defined by organization and distribution of neurons in the tissue. Today, most investigations in brain cytoarchitectonics are not automatized and require significant involvement of the researcher, which is very time consuming and may introduce significant bias. This type of analysis may not be accurate enough or reveal enough information about the structure of the tissue. Brain tissue forms complex structures whose organization and distribution may be reliably revealed only using systematic computational approach. The goal of this dissertation is development of novel computational methods for automatic and objective analysis of histological images of human brain suitable for advanced and fast analysis of brain cytoarchitectonics and laminar structure. The methods were developed aiming for a completely data-driven approach, with as little assumptions about the data as possible. Quantitative analysis of neuronal distribution and exploration of underlying principles of variation that facilitate parcellation of cortical layers resulted in novel framework and methodology for cellular-level investigations of brain tissue.Strukturu moždane kore definira organizacija i raspodijela neurona u tkivu mozga. Većina današnjih istraživanja u citoarhitektonici mozga nije automatizirana i zahtijeva značajnu uključenost istraživača i mnogo vremena, a što može uvesti i veliku pristranost. Ova vrsta analize često nije dovoljno precizna i ne otkriva dovoljno informacija o strukturi tkiva. Moždano tkivo tvori složene strukture čija se organizacija i distribucija mogu pouzdano otkriti samo uz primjenu sustavnog računarskog pristupa.Cilj ove disertacije je razvoj novih računalnih metoda za automatsku i objektivnu analizu histoloških slika ljudskog mozga pogodne za naprednu i brzu analizu citoarhitektonike mozga i laminarne strukture. Metode su razvijene pomoću pristupa vođenog podacima, uz što manje pretpostavki o samim podacima. Kvantitativna analiza raspodjele neurona i istraživanje temeljnih načela varijacije u tkivu koje uzrokuju parcelaciju kortikalnih slojeva rezultirala je novom znanstvenom metodologijom za istraživanje tkiva mozga na staničnoj razini