750 results match your criteria: "Technical University of Liberec[Affiliation]"

Objective Methods of Muscle Tone Diagnosis and Their Application-A Critical Review.

Sensors (Basel)

August 2023

Faculty of Science, Humanities and Education, Technical University of Liberec, 461 17 Liberec, Czech Republic.

"Muscle tone" is a clinically important and widely used term and palpation is a crucial skill for its diagnosis. However, the term is defined rather vaguely, and palpation is not measurable objectively. Therefore, several methods have been developed to measure muscle tone objectively, in terms of biomechanical properties of the muscle.

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Correction: Javed et al. Zinc Oxide Nanoparticles (ZnO NPs) and N-Methylol Dimethyl Phosphonopropion Amide (MDPA) System for Flame Retardant Cotton Fabrics. 2022, , 3414.

Polymers (Basel)

August 2023

Department of Nanochemistry, Institute for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec, Studentska 1402/2, 461 17 Liberec, Czech Republic.

The authors wish to make a correction to this paper [...

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Article Synopsis
  • * It examines how these extracts affect the expression of genes related to important skin functions, such as those for tyrosinase and collagenase, using human dermal fibroblast cells in vitro.
  • * Results indicate that while these extracts inhibit tyrosinase gene expression, they may not be beneficial for anti-aging cosmetics, as they alter the expression of other important skin-related genes; further research is needed.
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Hemiacetal-based dynamic systems: a new mechanistic insight.

Org Biomol Chem

August 2023

Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 8/2030, 128 40 Prague 2, Czech Republic.

The formation of hemiacetals from pyrazine trifluoromethylketone as a model receptor and four simple alcohols was studied by using quantum chemical calculations and NMR spectroscopy. Free energy profiles for four types of mechanistic pathways were calculated and discussed with respect to kinetic and thermodynamic measurements. We show that hemiacetal formation is facilitated by an assisted proton transfer process a pseudo eight-membered transition state which brings the theory and experiment into close agreement.

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Optimal Roving Winding on Toroidal Parts of Composite Frames.

Polymers (Basel)

July 2023

Department of Mathematics, Faculty of Science, Humanities and Education, Technical University of Liberec, Studentská 2, 461 17 Liberec, Czech Republic.

Frames made of polymer composites are increasingly used in the aerospace, automotive, and agricultural industries. A frequently used technology in the production line of composite frames is winding rovings onto a non-load-bearing frame to form the structure using an industrial robot and a winding head, which is solidified through a subsequent heat-treatment pressure process. In this technology, the most difficult procedure is the winding of the curved parts of a composite frame.

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The nickel-iron-based alloy Inconel 718 is a progressive material with very good mechanical properties at elevated and lower temperatures. It is used both as wrought and cast alloys as well as material for additive manufacturing technologies. This is the reason why it has received so much attention, as supported by numerous publications.

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Electrical characteristics of living cells have been proven to reveal important details about their internal structure, charge distribution and composition changes in the cell membrane, as well as the extracellular context. An impedance flow cytometry is a common approach to determine the electrical properties of a cell, having the advantage of label-free and high throughput. However, the current techniques are complex and costly for the fabrication process.

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Mineralized tissues, such as bones or teeth, are essential structures of all vertebrates. They enable rapid movement, protection, and food processing, in addition to providing physiological functions. Although the development, regeneration, and pathogenesis of teeth and bones have been intensely studied, there is currently no tool to accurately follow the dynamics of growth and healing of these vital tissues in space and time.

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Black & white relations: Intimate relationships of patients with borderline personality disorder.

Neuro Endocrinol Lett

July 2023

Department of Psychiatry, University Hospital Olomouc, Faculty of Medicine, Palacky University in Olomouc, Czech Republic.

Background: Individuals with borderline personality disorder (BPD) suffer from an excessive fear of abandonment, leading to tense moments in their intimate relationships. These struggles translate into lower marital satisfaction perceived by both intimate partners. However, this connection is bidirectional, since conflicts with a romantic partner are the most common precipitating factors of decompensation in BPD patients.

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This paper deals with the study of the degradation of polylactic acid (PLA) material structures and biocomposite systems with a PLA matrix containing ground natural particulate waste fillers, buckwheat husks and egg shells. Waste fillers were used without difficult cleaning operations to describe the effect of the raw waste material on PLA. Biocomposites with raw waste materials are increasingly coming to the forefront in car interiors and packaging products.

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Article Synopsis
  • The study examined the differences between calcined and milled aluminosilicates based on their particle size and how this affects geopolymer composites.
  • Two clay types, kaolin and kaolinitic claystone, were calcined and milled into various particle sizes, then mixed with potassium alkaline activator and quartz sand.
  • Results showed that finer particle sizes resulted in higher dissolved aluminum levels and increased viscosity in geopolymer binders, while larger particle sizes led to poorer mechanical performance in the composites.
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The Effect of Clearance Angle on Tool Life, Cutting Forces, Surface Roughness, and Delamination during Carbon-Fiber-Reinforced Plastic Milling.

Materials (Basel)

July 2023

Assembly and Engineering Metrology, Department of Machining, Faculty of Mechanical Engineering, Technical University of Liberec, 461 17 Liberec, Czech Republic.

This study aimed to investigate the effect of the clearance angle of the milling tool on wear, cutting forces, machined edge roughness, and delamination during non-contiguous milling of carbon-fiber-reinforced plastic (CFRP) composite panels with a twill weave and 90° fiber orientation. To achieve the objective of the study, it was first necessary to design suitable tools (6 mm diameter sintered carbide shank milling cutters) with a variety of clearance angles (8.4°, 12.

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Article Synopsis
  • Nanoparticles, particularly silica nanoparticles, are valuable in medicine, especially for cancer treatment due to their unique properties.
  • The study focused on assessing the cytotoxic effects of three types of silica nanoparticles (SiO2, SiO2-SH, and SiO2-COOH) on red blood cells and their impact on biological membranes.
  • The findings revealed that nanoparticle toxicity is concentration-dependent, with SiO2-COOH notably altering red blood cell shape and membrane fluidity, highlighting potential applications in biomedicine.
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How Czech Adolescents Perceive Their Physical Activity.

Children (Basel)

June 2023

Institute of Active Lifestyle, Faculty of Physical Culture, Palacký University, 771 11 Olomouc, Czech Republic.

Adolescence is a critical stage in the development of an individual's physical activity (PA) habits and preferences. Adolescents' perceptions of PA can influence their motivation to engage in PA and, consequently, their overall level of PA. Thus, our primary aim was to investigate whether Czech adolescents misperceive their peers' PA.

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Water Distribution Networks (WDNs) are considered one of the most important water infrastructures, and their study is of great importance. In the meantime, it seems necessary to investigate the factors involved in the failure of the urban water distribution network to optimally manage water resources and the environment. This study investigated the impact of influential factors on the failure rate of the water distribution network in Birjand, Iran.

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Stirred discs from polycaprolactone nanofibers highly doped with graphene for straightforward preconcentration of pollutants in environmental waters.

Talanta

January 2024

Charles University, Faculty of Pharmacy in Hradec Králové, The Department of Analytical Chemistry, Ak. Heyrovského 1203, 500 05, Hradec Králové, Czech Republic.

A novel sorbent for solid phase extraction (SPE) based on hybrid nanofibrous polycaprolactone containing graphene nanoparticles has been prepared. The preparation of hybrid polymer nanofibers with a very high 1:1 polymer/graphene ratio was achieved for the first time using alternating current electrospinning. The final appearance of these nanofibers was a thick porous layer that was cut into the shape of easy-to-handle extraction discs.

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Advanced (bio)fouling resistant surface modification of PTFE hollow-fiber membranes for water treatment.

Sci Rep

July 2023

Institute for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec, Studentská 1402/2, 461 17, Liberec 1, Czech Republic.

Membrane surface treatment to modify anti-(bio)fouling resistivity plays a key role in membrane technology. This paper reports on the successful use of air-stimulated surface polymerization of dopamine hydrochloride incorporated ZnO nanoparticles (ZnO NPs) for impeding the intrinsic hydrophobicity and low anti-(bio)fouling resistivity of polytetrafluoroethylene (PTFE) hollow-fiber membranes (HFMs). The study involved the use of pristine and polydopamine (Pdopa) coated PTFE HFMs, both with and without the presence of an air supply and added ZnO NPs.

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Chromium (Cr) pollution caused by the discharge of industrial wastewater into rivers poses a significant threat to the environment, aquatic and human life, as well as agricultural crops irrigated by these rivers. This paper employs artificial intelligence (AI) to introduce a new framework for modeling the fate, transport, and estimation of Cr from its point of discharge into the river until it is absorbed by agricultural products. The framework is demonstrated through its application to the case study River, which serves as the primary water resource for tomato production irrigation in Mashhad city, Iran.

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Utilization of spent coffee grounds as fillers to prepare polypropylene composites for food packaging applications.

Microsc Res Tech

November 2023

The Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, National Engineering Lab for Textile Fiber Materials and Processing Technology, School of Materials Science and Engineering, Zhejiang Sci-Tech University, Hangzhou, People's Republic of China.

Biomass-derived wastes as the additive of nondegradable plastics have been paid more attention due to the ever-growing environmental pollution and energy crisis. Herein, the spent coffee grounds (SCG) have been used as fillers in polypropylene (PP) after the heat treatment to realize its recycling utilization. The effect of the heat treatment atmosphere on the properties of the obtained SCG and SCG/PP composites has been investigated systematically.

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Destruction of Carbon and Glass Fibers during Chip Machining of Composite Systems.

Polymers (Basel)

June 2023

Department of Material Science, Department of Machining and Assembly, Faculty of Mechanical Engineering, Technical University of Liberec, 461 17 Liberec, Czech Republic.

Composite materials with carbon and glass fibers in an epoxy matrix are widely used systems due to their excellent mechanical parameters, and machining is a standard finishing operation in their manufacture. Previous studies focused exclusively on the characteristics of the fibers released into the air. This work aimed to analyze the nature of the material waste that remains on the work surface after machining.

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Case Study of Additively Manufactured Mountain Bike Stem.

Materials (Basel)

June 2023

The Institute for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec, Studentská 1402/2, 461 17 Liberec, Czech Republic.

This article is focused on a case study of the topology optimisation of a bike stem manufactured by selective laser melting (SLM) additive technology. Topology optimisation was used as a design tool to model a part with less material used for transferring specific loads than the conventional method. For topology optimisation, Siemens NX 12 software was used with loads defined from the ISO 4210-5 standard.

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Overusing pesticides, fertilizers, and synthetic dyes has significantly increased their presence in various parts of the environment. The transportation of these pollutants into agricultural soil and water through rivers, soils, and groundwater has seriously threatened human and ecosystem health. Applying techniques and materials to clean up agricultural sources from pesticides, heavy metals (HMs), and synthetic dyes (SDs) is one of the major challenges in this century.

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Sandwich Fibrous PEG Encapsulations for Thermal Energy Storage.

Chemphyschem

October 2023

Department of Material Engineering, Faculty of Textile Engineering, Technical University of Liberec, Studentska, 1402/2, Liberec, Czech Republic.

Phase change materials (PCMs) textiles have been developed for personal thermal management (PTM) while limited loading amount of PCMs in textiles reduced thermal buffering effect. In this work, we proposed a sandwich fibrous encapsulation to store polyethylene glycol (PEG) with PEG loading amount of 45 wt %, which consisted of polyester (PET) fabrics with hydrophobic coating as protection layers, polyurethane (PU) nanofibrous membranes as barrier layers and PEG-loaded viscose fabric as a PCM-loaded layer. The leakage was totally avoided by controlling weak interfacial adhesion between protection layer and melting PEG.

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Naproxen is one of the most used non-steroidal anti-inflammatory drugs (NSAIDs). It is used to treat pain of various origins, inflammation and fever. Pharmaceutical preparations containing naproxen are available with prescription and over-the-counter (OTC).

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