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1.
Molecules ; 27(13)2022 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-35807523

RESUMO

The measurement of nitric oxide (NO) in exhaled air is used in diagnostics and monitoring the pathologies not only in the respiratory system but also in the oral cavity. It has shown a huge increase in its level in asthma and diseases of the oral cavity. It seems reasonable to undertake research on the impact of inflammation on the level of NO in exhaled air. The aim of the study is to make an evidence-based review of the application of NO levels in exhaled air in the diagnosis of inflammation and treatment monitoring on the basis of selected measuring devices. METHODS AND RESULTS: This paper presents an example of the application of NO measurement in exhaled air in individual human systems. Selected measuring devices, their non-invasiveness, and their advantages are described. DISCUSSION: The usefulness of this diagnostic method in pathologies of the oral cavity was noted. CONCLUSIONS: Measuring the level of NO in exhaled air seems to be a useful diagnostic method.


Assuntos
Asma , Óxido Nítrico , Asma/diagnóstico , Asma/terapia , Expiração , Humanos , Inflamação/diagnóstico , Sistema Respiratório
2.
Int J Immunopathol Pharmacol ; 29(1): 112-20, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26634403

RESUMO

Controversy surrounds the role of dental infection/inflammation in the oral cavity in chronic spontaneous urticaria (CSU) and atrial fibrillation (AF), which is mainly due to scarce literature in this area. Therefore, this case report and review of literature illustrate a possible association between the acute-phase response (APR) and clinical conditions, such as CSU and dental infection/inflammation of oral cavity and AF.We describe a 36-year-old man with an 8-year history of difficult-to-treat, uncontrolled CSU, co-existent with dental infection/inflammatory processes of oral cavity and permanent atrial fibrillation (AF). In the presented case, the most likely triggering or aggravating/maintaining factor of the symptoms was the inflammation/dental infection of the oral cavity because of rapid reduction of the urticarial symptoms, drug doses, and serum CRP levels after the dental therapy. Dental treatment may have a beneficial effect on the systemic inflammatory response, reducing/normalizing the circulating levels of APR markers. APR activation appears to worsen CSU course, early identification and treatment of infectious/inflammatory foci in the oral cavity would form the mainstay of supportive therapy for CU probably through reduction of the systemic inflammatory burden. APR associated with infectious/inflammatory foci in the oral cavity could be taken into account as a predisposing agents to AF.


Assuntos
Fibrilação Atrial/etiologia , Infecções/complicações , Doenças Dentárias/complicações , Urticária/etiologia , Reação de Fase Aguda , Adulto , Proteína C-Reativa/análise , Doença Crônica , Humanos , Masculino
3.
Eur Child Adolesc Psychiatry ; 23(9): 845-50, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24276672

RESUMO

BACKGROUND: Nitric oxide (NO) is involved in eating behavior and inflammatory response. Moreover, there is evidence that NO production is altered in patients with anorexia nervosa (AN). AIM: To assess whether the overproduction of NO in AN can affect NO level in exhaled air. MATERIALS AND METHODS: Exhaled NO level was studied in 23 girls with AN and compared with that of healthy age- and gender-matched nonatopic controls. RESULTS: Exhaled NO levels were significantly higher in girls with AN compared with healthy age-matched controls. CONCLUSIONS: It appears that anorexia nervosa was accompanied by a higher level of exhaled NO, likely resulting from a systemic increase in NO production because of the severe catabolic state.


Assuntos
Anorexia Nervosa/metabolismo , Óxido Nítrico/análise , Adolescente , Anorexia Nervosa/diagnóstico , Biomarcadores/análise , Testes Respiratórios , Expiração , Feminino , Humanos , Masculino , Polônia , Testes de Função Respiratória
4.
J Biomech Eng ; 135(5): 54503, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-24231964

RESUMO

The results from clinical tests of single implant-retained dentures (SIDs) are quite promising. However, the biomechanics of SIDs are still insufficiently determined. The aim of the study was to compare the implant loads and pressures beneath one and two implant-retained dentures (TIDs) under oblique mastication forces. The finite element method was used to conduct a model analysis in order to compare loading of the denture attachment onto the implant that accompanies oblique mastication forces in the cases of SIDs and TIDs. The possibility of a denture detaching and sliding on the mucous membrane surface was simulated. The SID solution faced a more remarkable tilt in the direction of the mastication forces, a higher pressures on the mucous membrane surface, and higher implant loadings. The hingelike restraints in the TID favored utilization of the support in the posterior area. The higher pressure values for the SID can be confusing and could lead to inaccurate conclusions about the acceptability of the SID. In the TID, the same areas of the mucous membrane were persistently loaded, independent of the occlusal force direction. In contrast, in the SID the full freedom of rotational movement enhances alternating use of the mucous membrane. This finding explains the more frequent sores in the mucous membrane beneath the TID than beneath the SID.


Assuntos
Força de Mordida , Implantes Dentários , Dentaduras , Fenômenos Mecânicos , Fenômenos Biomecânicos , Análise de Elementos Finitos , Pressão
5.
J Clin Med ; 12(17)2023 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-37685622

RESUMO

BACKGROUND: Exhaled nitric oxide is helpful in the diagnosis of the inflammation process. The study aimed to analyze the impact of the COVID-19 disease on the oral bacterial flora of patients using complete dentures with a diagnostic device that measures the level of NO in exhaled air. MATERIALS AND METHODS: The study included patients using upper and lower acrylic complete dentures. All patients participating in the study were vaccinated against COVID-19. The patients were divided into two groups. A dental examination was conducted in each group. The NO concentration was measured using the Vivatmo Pro device. An oral microbiological examination was performed by taking a swab from the bottom of the mouth. RESULTS: There were no statistically significant differences in the distribution of NO in relation to the number of bacteria from isolated families in the study and control groups and no statistically significant correlations between the level of NO and the number of bacteria from all families in the control and study group. Significantly higher NO values were present in the vaccinated and COVID-19-positive history population compared to the vaccinated and with no COVID-19 history population (patients with no clinical symptoms of infection or unaware they had COVID-19). CONCLUSIONS: There are statistically significant differences in NO distribution in the considered populations: vaccinated and sick, and vaccinated and with a negative history of COVID-19. The measurement of NO in exhaled air can be a complementary, non-invasive diagnostic and inflammation monitoring method.

6.
Int J Mol Sci ; 14(1): 563-74, 2012 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-23271371

RESUMO

The colonization of denture soft lining material by oral fungi can result in infections and stomatitis of oral tissues. In this study, 0 ppm to 200 ppm of silver nanoparticles was incorporated as an antimicrobial agent into composites to reduce the microbial colonization of lining materials. The effect of silver nanoparticle incorporation into a soft lining material on the sorption, solubility, hardness (on the Shore A scale) and tensile bond strength of the composites was investigated. The data were statistically analyzed using two-way ANOVA and Newman-Keuls post hoc tests or the chi-square Pearson test at the p < 0.05 level. An increase in the nanosilver concentration resulted in a decrease in hardness, an increase in sorption and solubility, a decrease in bond strength and a change in the failure type of the samples. The best combination of bond strength, sorption, solubility and hardness with antifungal efficacy was achieved for silver nanoparticle concentrations ranging from 20 ppm to 40 ppm. These composites did not show properties worse than those of the material without silver nanoparticles and exhibited enhanced in vitro antifungal efficiency.


Assuntos
Forramento da Cavidade Dentária , Dentaduras , Teste de Materiais , Nanopartículas Metálicas/química , Prata/química , Adsorção , Dureza , Solubilidade , Resistência à Tração
7.
Healthcare (Basel) ; 10(2)2022 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-35206810

RESUMO

BACKGROUND: The most common cause of implant loss and deteriorating restoration aesthetics is infection and chronic inflammation of the tissues around the implants. Inflammation in the oral cavity, confirmed by clinical and histopathological examination and determination of exhaled nitric oxide, is a situation which may cause the complications on the whole human body. Elimination of the patology in the oral cavity in some cases is the only resonable treatment. The aims and objectives of our work is to present a gradual treatment of advanced infalmmation and present huge reduction stamp of inflammation measured with marker nitric oxide (NO) in exhaled air. MATERIALS AND METHODS: Simple treatment containing elimantion of pathology in the oral cavity was conducted. Patient that came to the dental practice suffered from the inflammation caused by lack of proper hygiene. First aid in this situation was to eliminate the inflammation which may affect negatively for general health. At first visit full hygienization was performed, at the second visit roots of abutment teeth and implants were removed under local anesthesia along with cystic changes. RESULTS: The hygiene precedures and extraction of the unsteady inflammationprosthetic restorations significantly decreased the level of NO in exhaled air. CONCLUSIONS: During the examination of the patient coming to the dental practice great attention should be paid to the coexistence of pathologies related to the oral cavity. Omission of a dental examination and possible elimination of odontogenic foci may affect the implication of the results of general diagnostics and subsequent treatment. Measuring the level of NO on exhaled air seems to be useful diagnostic method.

8.
J Clin Med ; 10(23)2021 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-34884262

RESUMO

The aim of this work is a review of recent scientific literature about intra-oral halitosis among patients using dentures. Halitosis is a condition in which an unpleasant smell comes out of the oral cavity, which is caused mainly by volatile sulfur and non-sulfured compounds. The etiology of halitosis may be intra- or extra-oral; in most patients, however, it is due to the activity of microorganisms in the oral cavity. The problem of the occurrence of intra-oral halitosis has accompanied patients for many years. In dental prosthetics, the problem of halitosis occurs in patients using removable or fixed dentures. In both cases, new niches for the development of microorganisms may be created, including those related to intra-oral halitosis. It should be noted that dentures-both fixed and removable-are a foreign body placed in the patient's oral cavity which, in case of insufficient hygiene, may constitute a reservoir of microorganisms, causing this unpleasant condition. Conventional treatment of intraoral halitosis reduces microbial activity via chemical and/or mechanical action. Currently, the search for new strategies in the treatment of halitosis is in progress. One idea is to use photodynamic therapy, while another is to modify poly(methyl methacrylate) (PMMA) with silver and graphene nanoparticles. Additionally, attempts have been made to combine those two methods. Another unconventional method of treating halitosis is the use of probiotics.

9.
Artigo em Inglês | MEDLINE | ID: mdl-34574415

RESUMO

The main functional feature of elastomeric soft linings materials is the ability to discharge loads in the tissues of the mucosa. As a result, there are fewer injuries to the mucosa and chewing ability increases. In addition, these prostheses are more comfortable in the patient's opinion. To obtain the equal distribution of forces on the muco-bone basis and to reduce the traumatizing effect of the denture plate for patients using full dentures, soft lining materials can be used. AIM OF THE STUDY: the aim of the work was a comparative laboratory study of ten materials used for soft lining of acrylic complete dentures. METHODOLOGY: Materials based on acrylates (Vertex Soft, Villacryl Soft, Flexacryl Soft) and on silicones (Sofreliner Tough Medium, Sofreliner Tough Medium, Ufi Gel SC, GC Reline Soft, Elite Soft Relining, Molloplast) were compared. Laboratory tests include tests of changes in Shore'a A hardness of soft lining material. The tests were conducted taking into account 90 day term aging in the distilled water environment based on the methodology presented in the European Standard ISO 10139-2. RESULTS: For most silicone materials, only small changes in hardness were found in the range of 0.7 (Ufi Gel SC) to 3.3 (Sofreliner Tough Medium) on the Shore A scale. The exception was GC Reline Soft, for which a marked increase in hardness was noted. All materials based on acrylates were characterized by successive increase in hardness over time. However, in the case of the Vertex Soft material, the increase in hardness was relatively small (5.5 ShA).


Assuntos
Reembasadores de Dentadura , Dureza , Humanos , Teste de Materiais
10.
Materials (Basel) ; 14(22)2021 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-34832270

RESUMO

Abrasions and pressure ulcers on the oral mucosa are most often caused by excessive pressure or incorrect fitting of the denture. The use of soft relining materials can eliminate pain sensations and improve patient comfort. The main functional feature of soft elastomeric materials is the ability to discharge loads from the tissues of the mucosa. (1) Background: The aim of the work was a comparative laboratory study of ten materials used for the soft lining of acrylic dentures. (2) Methods: There were materials based on acrylates (Vertex Soft, Villacryl Soft, Flexacryl Soft) and silicones (Sofreliner Tough Medium, Sofreliner Tough Medium, Ufi Gel SC, GC Reline Soft, Elite Soft Relining, Molloplast). Laboratory tests include the analysis of the tensile bond strength between the relining material and the acrylic plate of the prosthesis. The tests were conducted taking into account 90-day term aging in the distilled water environment based on the methodology presented in the European Standard ISO 10139-2. (3) Results: After three months of observation, the highest strength of the joint was characterized by Flexacryl Soft acrylic, for which the average value was 2.5 MPa. The lowest average value of 0.89 MPa was recorded for the GC Reline Soft silicone material. Over time, an increase in the value of the strength of the combination of acrylic materials and a decrease in these values in the case of silicone materials was observed. (4) Conclusion: Each of the tested silicone materials showed all three types of damage, from adhesive to mixed to cohesive. All acrylic-based materials showed an adhesive type of failure. Time did not affect the type of destruction.

11.
Materials (Basel) ; 13(19)2020 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-33023200

RESUMO

In the interest of environmental protection, attention should be paid to improving energy efficiency, through the use of appropriate insulations. They can be used in the construction industry, for plastic window frames, and the thermal insulation of buildings. It is also possible to use these materials in the electronics industry, for hermetic casings of devices, in the aviation industry, as well as in the food industry, as collective packaging for frozen food. The technology of using additive 3D printing to create prototype insulating materials made of plastic is proposed in this article. Multi-layer materials, with quadrangle, hexagonal, and triangle closures were designed and printed. A mathematical model was developed, and then experimentally verified. Quadrangle and hexagonal structures were shown to be useful, and triangle structures to be of little use. The optimal size of closure was determined to be 10 mm, with no convection, and 6 mm, with possible convection. The lowest thermal conductivity of the insulation was 0.0591 W/(m·K) for 10 mm single-layer quadrangle and hexagonal closures with an insulation density of 180 kg/m3.

12.
Photochem Photobiol ; 96(3): 539-549, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32112419

RESUMO

The purpose of this review is to present an overview of the development of photodiagnostic and photodynamic therapy (PDD and PDT) techniques in Poland. The paper discusses the principles of PDD, including fluorescent techniques in determining precancerous conditions and cancers of the skin, digestive tract, bladder and respiratory tract. Methods of PDT of cancer will be discussed and the current state of knowledge as well as future trends in the development of photodynamic techniques will be presented, including the possibility of using photodynamic antimicrobial therapy. Research pioneers in photodynamic medicine such as Thomas Dougherty are an inspiration for the development of methods of PDD and PDT in our Clinic. The Center for Laser Diagnostics and Therapy in Bytom, Poland, promotes the propagation of PDD and PDT through the training of clinicians and raising awareness among students in training and the general public. Physicians at the Center are engaged in photomedical research aimed at clinical implementation and exploration of new avenues in photomedicine while optimizing existing modalities. The Center promotes dissemination of clinical results from a wide range of topics in PDD and PDT and serving as representative authorities of photodynamic medicine in Poland and Europe.


Assuntos
Ensaios Clínicos como Assunto , Fotoquimioterapia , Doenças Cardiovasculares/diagnóstico , Doenças Cardiovasculares/etiologia , Oftalmopatias/diagnóstico , Oftalmopatias/tratamento farmacológico , Humanos , Lasers , Pneumopatias/diagnóstico , Pneumopatias/tratamento farmacológico , Neoplasias/diagnóstico , Neoplasias/tratamento farmacológico , Fármacos Fotossensibilizantes , Polônia , Doenças Urológicas/diagnóstico , Doenças Urológicas/tratamento farmacológico
13.
Pharmacol Rep ; 61(2): 311-8, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19443944

RESUMO

To assess the possible modulatory effects of noradrenergic and serotoninergic neurons on dopaminergic neuronal activity, the noradrenergic and serotoninergic neurotoxins DSP-4 N-(2-chlorethyl)-N-ethyl-2-bromobenzylamine (50.0 mg/kg, sc) and 5,7-dihydroxytryptamine (5,7-DHT) (37.5 microg icv, half in each lateral ventricle), respectively, were administered toWistar rats on the first and third days of postnatal ontogeny, and dopamine (DA) agonist-induced behaviors were assessed in adulthood. At eight weeks, using an HPLC/ED technique, DSP-4 treatment was associated with a reduction in NE content of the corpus striatum (> 60%), hippocampus (95%), and frontal cortex (> 85%), while 5,7-DHT was associated with an 80-90% serotonin reduction in the same brain regions. DA content was unaltered in the striatum and the cortex. In the group lesioned with both DSP-4 and 5,7-DHT, quinpirole-induced (DA D(2) agonist) yawning, 7-hydroxy-DPAT-induced (DA D(3) agonist) yawning, and apomorphine-induced (non-selective DA agonist) stereotypies were enhanced. However, SKF 38393-induced (DA D(1) agonist) oral activity was reduced in the DSP-4 + 5,7-DHT group. These findings demonstrate that DA D(2)- and D(3)-agonist-induced behaviors are enhanced while DA D(1)-agonist-induced behaviors are suppressed in adult rats in which brain noradrenergic and serotoninergic innervation of the brain has largely been destroyed. This study indicates that noradrenergic and serotoninergic neurons have a great impact on the development of DA receptor reactivity (sensitivity).


Assuntos
5,7-Di-Hidroxitriptamina/toxicidade , Comportamento Animal/efeitos dos fármacos , Benzilaminas/toxicidade , Agonistas de Dopamina/farmacologia , Receptores de Dopamina D2/agonistas , Animais , Animais Recém-Nascidos , Comportamento Exploratório/efeitos dos fármacos , Masculino , Atividade Motora/efeitos dos fármacos , Norepinefrina/fisiologia , Quimpirol/farmacologia , Ratos , Ratos Wistar , Receptores de Dopamina D2/fisiologia , Serotonina/fisiologia
14.
Photodiagnosis Photodyn Ther ; 27: 255-267, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31226444

RESUMO

BACKGROUND: Oral cavity squamous cell carcinoma is a common cancer of the head and neck region. Due to the frequency of diagnoses, high rate of mortality, mutilating nature of classic therapy and numerous complications, new methods of treatment are being sought. One promising solution for treatment which is utilized in many fields of oncology is photodynamic therapy. The purpose of this article is to present a general overview of the use of photodynamic therapy in preclinical in vitro studies. MATERIALS AND METHODS: A literature search for articles corresponding to the topic of this review was performed using the PubMed and MEDLINE databases using the following keywords: 'oral cavity squamous cell carcinoma,' 'photodynamic therapy,' 'photosensitizer(s),' 'in vitro,' 'cell culture(s),' 'spheroids,' 'CAM model', and 'in vivo.' RESULTS: Most of the previous work found in the literature search concerns research on the use of various photosensitizers and the determination of their level of phototoxicity against cell lines. CONCLUDING REMARKS: Research on the photodynamic effect in cell lines may be useful in establishing the mechanisms and effectiveness of the photodynamic method as a starting point for clinical trials. Studies on spheroidal models allows for testing photodynamic therapy under more clinical-like conditions. The Chick Chorioallantoic Membrane Assay provides information about the vascular changes after treatment.


Assuntos
Carcinoma de Células Escamosas/tratamento farmacológico , Neoplasias Bucais/tratamento farmacológico , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/uso terapêutico , Humanos , Técnicas In Vitro , Fármacos Fotossensibilizantes/administração & dosagem , Fármacos Fotossensibilizantes/efeitos adversos
15.
Acta Bioeng Biomech ; 20(2): 89-100, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30220709

RESUMO

INTRODUCTION: Multifactorial aetiologies of painful temporomandibular disorders (TMD) have an impact on correct diagnosis and consequently prevent proper treatment. AIM OF THE STUDY: The aim of the study was to evaluate the effect of magnetic stimulation on electromyographic activity in temporal muscles and masseters in patients using occlusal splints. MATERIALS AND METHODS: The examined group consisted of 40 edentulous patients with TMD. The patients were examined based on Helkimo Index. Next, electromyographic activity of the temporal muscle and masseter were investigated using 8-channel surface electromyography. All patients received acrylic occlusal splints for 12 weeks. The group qualified for the study included 20 randomized patients, whose therapy was additionally carried out by extremely low-frequency magnetic fields for a period of 21 days. Following examinations were conducted after 3, 6 and 12 weeks with surface electromyography recording of the examined muscles. Patients received occlusal splint corrections using the T-Scan III system. The clinical evaluation of TMD was analysed using Helkimo index and VAS scale before and after the treatment. All the data were analysed using Statistica 12.5 PL. RESULTS: Patients with combination therapy had lower asymmetry of temporal muscle activity. CONCLUSIONS: Combination therapy using magnetic stimulation reduced intensity of pain in patients with TMD and decreased values of the Helkimo indices.


Assuntos
Arcada Edêntula/complicações , Arcada Edêntula/fisiopatologia , Magnetismo , Músculo Masseter/fisiopatologia , Dor/fisiopatologia , Músculo Temporal/fisiopatologia , Transtornos da Articulação Temporomandibular/complicações , Transtornos da Articulação Temporomandibular/fisiopatologia , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
16.
Materials (Basel) ; 11(2)2018 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-29470441

RESUMO

Colonization of silicone-based soft lining materials by pathogenic yeast-type fungi is a common problem associated with the use of dentures. In this study, silver sodium hydrogen zirconium phosphate (SSHZP) was introduced into polydimethylsiloxane-based material as an antimicrobial filler at concentrations of 0.25, 0.5, 1, 2, 4, 6, 8, 10, 12, and 14% (w/w). The in vitro antimicrobial efficacy was investigated. Candida albicans was used as a characteristic representative of pathogenic oral microflora. Staphylococcus aureus and Escherichia coli were used as the typical Gram-positive and Gram-negative bacterial strains, respectively. The effect of filler addition on the Shore A hardness, tensile strength, tensile bond strength, sorption, and solubility was investigated. An increase in the filler concentration resulted in an increase in hardness, sorption, and solubility, and for the highest concentration, a decrease in bond strength. The favorable combination of antimicrobial efficacy with other properties was achieved at filler concentrations ranging from 2% to 10%. These composites exhibited mechanical properties similar to the material without the antimicrobial filler and enhanced in vitro antimicrobial efficiency.

17.
Materials (Basel) ; 11(11)2018 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-30400231

RESUMO

In the published article, "Properties of Experimental Dental Composites Containing Antibacterial Silver-Releasing Filler" [...].

18.
Materials (Basel) ; 11(6)2018 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-29912158

RESUMO

Secondary caries is one of the important issues related to using dental composite restorations. Effective prevention of cariogenic bacteria survival may reduce this problem. The aim of this study was to evaluate the antibacterial activity and physical properties of composite materials with silver sodium hydrogen zirconium phosphate (SSHZP). The antibacterial filler was introduced at concentrations of 1%, 4%, 7%, 10%, 13%, and 16% (w/w) into model composite material consisting of methacrylate monomers and silanized glass and silica fillers. The in vitro reduction in the number of viable cariogenic bacteria Streptococcus mutans ATCC 33535 colonies, Vickers microhardness, compressive strength, diametral tensile strength, flexural strength, flexural modulus, sorption, solubility, degree of conversion, and color stability were investigated. An increase in antimicrobial filler concentration resulted in a statistically significant reduction in bacteria. There were no statistically significant differences caused by the introduction of the filler in compressive strength, diametral tensile strength, flexural modulus, and solubility. Statistically significant changes in degree of conversion, flexural strength, hardness (decrease), solubility (increase), and in color were registered. A favorable combination of antibacterial properties and other properties was achieved at SSHZP concentrations from 4% to 13%. These composites exhibited properties similar to the control material and enhanced in vitro antimicrobial efficiency.

19.
Materials (Basel) ; 10(8)2017 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-28805703

RESUMO

This article presents the results of a study into a packed bed filled with ceramic bricks. The designed storage installation is supposed to become part of a heating system installed in a single-family house and eventually to be integrated with a concentrated solar collector adapted to climate conditions in Poland. The system's working medium is air. The investigated temperature ranges and air volume flow rates in the ceramic bed were dictated by the planned integration with a solar air heater. Designing a packed bed of sufficient parameters first required a mathematical model to be constructed and heat exchange to be analyzed, since heat accumulation is a complex process influenced by a number of material properties. The cases discussed in the literature are based on differing assumptions and different formulas are used in calculations. This article offers a comparison of various mathematical models and of system operating parameters obtained from these models. The primary focus is on the Nusselt number. Furthermore, in the article, the thermo-hydraulic efficiency of the investigated packed bed is presented. This part is based on a relationship used in solar air collectors with internal storage.

20.
Acta Bioeng Biomech ; 19(1): 47-53, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28552918

RESUMO

PURPOSE: This paper presents the study aimed at the development of crosslinked poly(methyl methacrylate)s (X-PMMA) of varied crosslink density and the investigation of the relationships between the polymer network structure and dynamic mechanical properties. METHODS: A series of model X-PMMA networks were crosslinked by the introduction of: 1, 2, 5, 10 and 20% of triethylene glycol dimethacrylate (TEGDMA). The copolymerizations led to various glass-rubber relaxation properties of the polymer networks, as revealed by dynamic-mechanical analysis (DMA). Glass temperature (Tg) and storage modulus above the Tg (Erubbery ) were a sensitive function of network architecture. DMA data were used for calculating the network parameter (Mc), crosslink density (q) and its alternative measure - the degree of crosslinking (DX). RESULTS: The viscoelastic properties as well as structural parameters calculated from those showed correlation with the amount of the crosslinker. The increase in TEGDMA content resulted in the Tg, q and DX increases, whereas Mc decrease. The possible incomplete conversion of double bonds was detected in the DMA analysis, which was confirmed by the degree of conversion (DC), measured by FTIR spectroscopy. Additionally, some amount of sol fraction was found by 1H NMR experiments. CONCLUSIONS: The structure-property relationships developed for the system presented in this work could be useful in tissue engineering, where X-PMMA is applied. The direct measure of storage modulus values before and above glass transition may serve as a simple and fast indicator of the X-PMMA crosslink density.


Assuntos
Cimentos Ósseos/química , Reagentes de Ligações Cruzadas/química , Portadores de Fármacos/química , Teste de Materiais/métodos , Modelos Químicos , Polimetil Metacrilato/química , Simulação por Computador , Armazenamento de Medicamentos , Módulo de Elasticidade , Viscosidade
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