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1.
Biol Lett ; 20(5): 20240041, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38773928

RESUMEN

Corneous skin appendages are not only common and diverse in crown-group amniotes but also present in some modern amphibians. This raises the still unresolved question of whether the ability to form corneous skin appendages is an apomorphy of a common ancestor of amphibians and amniotes or evolved independently in both groups. So far, there is no palaeontological contribution to the issue owing to the lack of keratin soft tissue preservation in Palaeozoic anamniotes. New data are provided by a recently discovered ichnofossil specimen from the early Permian of Poland that shows monospecific tetrapod footprints associated with a partial scaly body impression. The traces can be unambiguously attributed to diadectids and are interpreted as the globally first evidence of horned scales in tetrapods close to the origin of amniotes. Taking hitherto little-noticed scaly skin impressions of lepospondyl stem amniotes from the early Permian of Germany into account, the possibility has to be considered that the evolutionary origin of epidermal scales deeply roots among anamniotes.


Asunto(s)
Evolución Biológica , Epidermis , Fósiles , Animales , Fósiles/anatomía & histología , Epidermis/anatomía & histología , Anfibios/anatomía & histología , Anfibios/clasificación , Polonia , Escamas de Animales/anatomía & histología , Piel/anatomía & histología
2.
J Craniofac Surg ; 28(5): e422-e431, 2017 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-28570402

RESUMEN

Mandibular prognathism is defined as an abnormal forward projection of the mandible beyond the standard relation to the cranial base and it is usually categorized as both a skeletal Class III pattern and Angle Class III malocclusion. The etiology of mandibular prognathism is still uncertain, with various genetic, epigenetic, and environmental factors possibly involved. However, many reports on its coexistence in both twins and segregation in families suggest the importance of genetic influences. A multifactorial and polygenic background with a threshold for expression or an autosomal dominant mode with incomplete penetrance and variable expressivity are the most probable inheritance patterns. Linkage analyses have, thus far, shown the statistical significance of such loci as 1p22.1, 1p22.3, 1p32.2, 1p36, 3q26.2, 4p16.1, 6q25, 11q22, 12pter-p12.3, 12q13.13, 12q23, 12q24.11, 14q24.3 to 31.2, and 19p13.2. The following appear among candidate genes: MATN1, EPB41, growth hormone receptor, COL2A1, COL1A1, MYO1H, DUSP6, ARHGAP21, ADAMTS1, FGF23, FGFR2, TBX5, ALPL, HSPG2, EVC, EVC2, the HoxC gene cluster, insulin-like growth factor 1, PLXNA2, SSX2IP, TGFB3, LTBP2, MMP13/CLG3, KRT7, and FBN3. On the other hand, MYH1, MYH2, MYH3, MYH7, MYH8, FOXO3, NFATC1, PTGS2, KAT6B, HDAC4, and RUNX2 expression is suspected to be involved in the epigenetic regulations behind the mandibular prognathism phenotype.


Asunto(s)
Maloclusión de Angle Clase III/genética , Mandíbula , Prognatismo/genética , Cefalometría/métodos , Proteínas del Citoesqueleto/genética , Factor-23 de Crecimiento de Fibroblastos , Ligamiento Genético , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Imagenología Tridimensional/métodos , Maloclusión de Angle Clase III/diagnóstico , Mandíbula/anomalías , Mandíbula/diagnóstico por imagen , Prognatismo/diagnóstico
3.
J Craniofac Surg ; 27(7): 1842-1844, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27557467

RESUMEN

Many types of surgical osteotomies of the cranio-facial skeleton relay on adequate surgical field preparation. Placement and stabilization of nasotracheal tube during orthognathic surgery is very important. In most cases, long-lasting surgery includes various surgical maneuvers around patient's skull, which depend on accurate nasotracheal tube stabilization. Usage of adhesive plasters for heavy anesthetic tube connector placement and stability might result in tube instability and local disfigurement of nasal projection and visibility in the nasal and infraorbital areas. We present a novel technique for nasotracheal tube stabilization allowing each surgeon controlling tube position, visual evaluation of nasal projection, and its tip during various surgical movements of maxillary bone, such as extrusion, intrusion, rotation or others, during Le Fort I osteotomy. Despite additional time necessary for preparation of surgical field, attachment of the tube and suturing, presented method allows achieving very satisfactory final outcomes with visible access to key nasal structures important in Le Fort I osteotomy. Presented method could be also used in any other facial surgery procedure.


Asunto(s)
Anomalías Craneofaciales/cirugía , Intubación Intratraqueal/instrumentación , Nariz/cirugía , Cirugía Ortognática/métodos , Osteotomía Le Fort/métodos , Técnicas de Sutura , Tráquea/cirugía , Adolescente , Adulto , Femenino , Humanos , Masculino
4.
J Craniofac Surg ; 26(1): e42-4, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25565232

RESUMEN

Dandy-Walker syndrome is a rare congenital brain deformation. Most symptoms are related with fourth ventricle and skull base malformations. Quite often, symptoms develop from infancy or progress rapidly. Cerebellar dysfunction, lack of muscle coordination, and skull deformities involving eye movement might be present. There are several Dandy-Walker syndrome complex types. We present a 23-year-old patient who had a severe dentofacial deformity with mandibular prognathism and extremely undeveloped maxillary bone resulting in palatopharyngeal and velopharyngeal dysfunction with complete lack of soft palate function resulting in increased speech tone and volume. Performing Le Fort I osteotomy in this case is greatly controversial and might result in even greater loss of function or even its total lack. Velopharyngeal complex is very important, and every surgeon should consider its value while planning Le Fort I osteotomies.


Asunto(s)
Síndrome de Dandy-Walker/cirugía , Osteotomía Le Fort , Insuficiencia Velofaríngea/etiología , Contraindicaciones , Deformidades Dentofaciales/cirugía , Humanos , Maxilar/anomalías , Paladar Blando/anomalías , Paladar Blando/fisiopatología , Planificación de Atención al Paciente , Faringe/anomalías , Prognatismo/cirugía , Trastornos del Habla/etiología , Tomografía Computarizada por Rayos X/métodos , Trastornos de la Voz/etiología , Adulto Joven
5.
Postepy Hig Med Dosw (Online) ; 69: 996-1002, 2015 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-26400886

RESUMEN

The facial nerve (VII) is one of the most important cranial nerves for head and neck surgeons. Its function is closely related to facial expressions that are individual for every person. After its injury or palsy, its functions can be either impaired or absent. Because of the presence of motor, sensory and parasympathetic fibers, the biology of its repair and function restoration depends on many factors. In order to achieve good outcome, many different therapies can be performed in order to restore as much of the nerve function as possible. When rehabilitation and physiotherapy are not sufficient, additional surgical procedures and therapies are taken into serious consideration. The final outcome of many of them is discussable, depending on nerve damage etiology. Stem cells in facial nerve repair are used, but long-term outcomes and results are still not fully known. In order to understand this therapeutic approach, clinicians and surgeons should understand the immunobiology of nerve repair and regeneration. In this review, potential stem cell usage in facial nerve regeneration procedures is discussed.


Asunto(s)
Nervio Facial/cirugía , Regeneración Nerviosa/fisiología , Células Madre/fisiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Humanos , Lactante , Recién Nacido , Persona de Mediana Edad , Trasplante de Células Madre/métodos , Adulto Joven
6.
Folia Med Cracov ; 55(4): 49-57, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26867119

RESUMEN

In search for novel effective treatments in inflammatory bowel diseases, a new strategy employing glass beads coated with rhenium nanolayer has been developed and validated in the mouse model of 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis. Briefly, mice were randomly divided into 5 experimental groups: control (vehicle alone, Group 1); control treated with rhenium-coated glass beads (Group 2); TNBS (Group 3); TNBS treated with rhenium-coated glass beads (Group 4); and TNBS treated with uncoated glass beads (Group 5). Mice from Group 2, 4 and 5 were treated with respective beads (once daily, 5 beads / animal, i.c.) between D3-D6 post-TNBS/vehicle and evaluation of colonic damage was performed on D7, based on macroscopic scoring and clinical parameters. Severe colonic inflammation developed in post-TNBS mice (Group 3) [P <0.001 vs. control (Group 1) for macroscopic score], which was significantly attenuated by treatment with rhenium-coated glass beads (Group 4) [P <0.01 vs. TNBS (Group 3), for macroscopic score]. Neither rhenium-coated glass beads had any effect in control animals (Group 2), nor uncoated glass beads influenced TNBS-induced colitis (Group 5). In conclusion, a novel and attractive strategy for the treatment of colonic inflammation has been proposed; therapy with rhenium-coated glass beads already proved effective in the mouse model of TNBS-induced colitis, now requires further characterization in clinical conditions.


Asunto(s)
Antiinflamatorios/farmacología , Materiales Biocompatibles/farmacología , Colitis Ulcerosa/tratamiento farmacológico , Fármacos Gastrointestinales/farmacología , Vidrio , Renio , Animales , Colitis Ulcerosa/prevención & control , Colon/efectos de los fármacos , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Ratones , Ratones Endogámicos BALB C , Ácido Trinitrobencenosulfónico/administración & dosificación
7.
J Craniofac Surg ; 25(2): 517-8, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24577305

RESUMEN

Six cranial fontanelles are present in newborns along with cranial sutures. Cranial sutures are a synarthrosis type of joints that occur in the skull after closure of fontanelles. Because of ossification up to 24 months, all fontanelles should be closed. Normal frontal bone consists of only frontonasal, frontozygomatic, frontomaxillaris, frontolacrimalis, and main coronal sutures. Metopic frontal suture occurs very rarely in adults. Some metopic frontal sutures might be related to genetic or general disorders or perhaps are related to an improper ossification. In some cases, it persists as a complete suture extending from the nasion to the anterior angle of the bregma, and this condition is called metopism, or metopic suture. In this article, we present a patient with metopic frontal suture diagnosed accidentally during preparation for bimaxillary orthognathic surgery.


Asunto(s)
Fontanelas Craneales/anomalías , Suturas Craneales/anomalías , Deformidades Dentofaciales/cirugía , Hueso Frontal/anomalías , Hallazgos Incidentales , Procedimientos Quirúrgicos Ortognáticos/métodos , Fontanelas Craneales/diagnóstico por imagen , Suturas Craneales/diagnóstico por imagen , Deformidades Dentofaciales/diagnóstico por imagen , Femenino , Hueso Frontal/diagnóstico por imagen , Humanos , Imagenología Tridimensional/métodos , Maloclusión de Angle Clase III/cirugía , Maxilar/anomalías , Mordida Abierta/cirugía , Tomografía Computarizada por Rayos X/métodos , Adulto Joven
8.
Postepy Hig Med Dosw (Online) ; 68: 119-28, 2014 Feb 03.
Artículo en Inglés | MEDLINE | ID: mdl-24491903

RESUMEN

Photodynamic therapy (PDT) is a special type of treatment involving the use of a photosensitizer or a photosensitizing agent along with a special type of light, which, combined together, induces production of a form of oxygen that is used to kill surrounding cells in different areas of the human body. Specification of the head and neck region requires different approaches due to the surrounding of vital structures. PDT can also be used to treat cells invaded with infections such as fungi, bacteria and viruses. The light beam placed in tumor sites activates locally applied drugs and kills the cancer cells. Many studies are taking place in order to invent better photosensitizers, working on a larger scale and to treat deeply placed and larger tumors. It seems that PDT could be used as an alternative surgical treatment in some tumor types; however, all clinicians should be aware that the surgical approach is still the treatment of choice. PDT is a very accurate and effective therapy, especially in early stages of head and neck squamous cell carcinomas (HNSCC), and can greatly affect surgical outcomes in cancerous patients. We present a detailed review about photosensitizers, their use, and therapeutic advantages and disadvantages.


Asunto(s)
Neoplasias de Cabeza y Cuello/tratamiento farmacológico , Fotoquimioterapia , Fármacos Fotosensibilizantes/uso terapéutico , Carcinoma de Células Escamosas/tratamiento farmacológico , Carcinoma de Células Escamosas/cirugía , Neoplasias de Cabeza y Cuello/cirugía , Humanos , Carcinoma de Células Escamosas de Cabeza y Cuello
9.
Diagnostics (Basel) ; 14(10)2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38786312

RESUMEN

Unilateral condylar hyperplasia (UCH) is a rare cause of asymmetrical mandibular overgrowth because of the presence of an atypical growth in the affected condyle. SPECT (single-photon emission computed tomography) can easily establish the presence of an atypical, prolonged growth exceeding far beyond normal condylar growth and activity. A CT, CBCT, or LDCT (computed tomography, cone-beam computed tomography, or low-dose computed tomography) can confirm the diagnosis by evaluating the scope of bone overgrowth, mandibular basis/ramus asymmetry, tendency to condylar head enlargement, changes in bone density, and occurrence of differences in condylar head shapes, size, and bone structure. In most cases, a condylectomy is the procedure of choice in growing cases of UCH to remove the pathological condyle and reduce asymmetry levels. Sometimes, the growth is very slow and progressive over time, causing slowly growing asymmetry with similar symptoms to any other mandibular asymmetry, and this causes some troublesome procedures in UCH diagnostics, resulting in patients being underdiagnosed; it can even lead to some relapses in mandibular asymmetry and skeletal malocclusion after previously performed orthodontic and surgical treatment of such discrepancies. When the source of asymmetry is not identified in time, possible inadequate treatment protocols can be used. If any relapse of facial and mandibular asymmetry re-occur, SPECT and CT evaluation are necessary to evaluate if condylar hyperplasia is present and to establish what kind of surgical intervention should be used in each case.

10.
Neuro Endocrinol Lett ; 34(2): 107-10, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23645306

RESUMEN

OBJECTIVE: Giant cell tumors of the maxillofacial skeleton are uncommon, they are usually late manifestation of primary hyperparathyroidism. A series of five clinical cases in four women and one man presenting as the giant cell lesions in the maxilla and/or mandible are discussed. METHODS: Biopsy of the lesions, biochemical and hormonal analyses, densitometry and parathyroid scintigraphy were carried out. RESULTS: Biopsy of the lesions showed giant cell tumor of bone. The medical history and laboratory analyses showed primary hyperparathyroidism. Bone density loss was documented and scintigraphy revealed the presence of parathyroid adenomas in four cases. Surgical treatment of hyperparathyroidism, and in the second step - after 6-12 months - the subsequent excision of residual brown tumors in all cases was performed. CONCLUSIONS: One should have in mind that osteolytic bone lesions may be due to metabolic disease of the bone. Accurate diagnosis enabling the proper treatment should be carried out, avoiding unnecessary harm to the patients.


Asunto(s)
Tumores de Células Gigantes/patología , Hiperparatiroidismo Primario/patología , Neoplasias Maxilomandibulares/patología , Neoplasias Maxilares/patología , Neoplasias de las Paratiroides/patología , Adulto , Anciano , Biopsia/métodos , Femenino , Tumores de Células Gigantes/diagnóstico , Tumores de Células Gigantes/cirugía , Humanos , Hiperparatiroidismo Primario/diagnóstico , Hiperparatiroidismo Primario/cirugía , Neoplasias Maxilomandibulares/cirugía , Masculino , Neoplasias Maxilares/diagnóstico , Neoplasias Maxilares/cirugía , Persona de Mediana Edad , Neoplasias de las Paratiroides/diagnóstico , Neoplasias de las Paratiroides/cirugía , Resultado del Tratamiento
11.
Polymers (Basel) ; 15(10)2023 May 09.
Artículo en Inglés | MEDLINE | ID: mdl-37242811

RESUMEN

MoS2 is an additive used to improve the tribological properties of plastics. In this work, it was decided to verify the use of MoS2 as a modifier of the properties of PLA filaments used in the additive FDM/FFF technique. For this purpose, MoS2 was introduced into the PLA matrix at concentrations of 0.025-1.0% by weight. Through extrusion, a fibre with a diameter of 1.75 mm was obtained. 3D printed samples with three different filling patterns were subjected to comprehensive thermal (TG, DSC and HDT), mechanical (impact, bending and strength tests), tribological and physicochemical characteristics. The mechanical properties were determined for two different types of fillings, and samples with the third type of filling were used for tribological tests. Tensile strength has been significantly increased for all samples with longitudinal filling with improvement up to 49%. In terms of tribological properties, higher values of the addition (0.5%) caused a significant increase of up to 457% of the wear indicator. A significant improvement in processing properties in terms of rheology was obtained (416% compared to pure PLA with the addition of 1.0%), which translated into more efficient processing, increased interlayer adhesion and mechanical strength. As a result, the quality of printed objects has been improved. Microscopic analysis was also carried out, which confirmed the good dispersion of the modifier in the polymer matrix (SEM-EDS). Microscopic techniques (MO, SEM) allowed for the characterization of the effect of the additive on changes in the printing process (improvement of interlayer remelting) and to assess impact fractures. In the tribological area, the introduced modification did not bring spectacular effects.

12.
Materials (Basel) ; 15(19)2022 Oct 05.
Artículo en Inglés | MEDLINE | ID: mdl-36234250

RESUMEN

This article describes the manufacturing of alumina composites with the addition of titanium aluminum carbide Ti3AlC2, known as MAX phases. The composites were obtained by the powder metallurgy technique with three types of mill (horizontal mill, attritor mill, and planetary mill), and were consolidated with the use of the Spark Plasma Sintering method at 1400 °C, with dwelling time 10 min. The influence of the Ti3AlC2 MAX phase addition on the microstructure and mechanical properties of the obtained composites was analyzed. The structure of the MAX phase after the sintering process was also investigated. The chemical composition and phase composition analysis showed that the Ti3AlC2 addition preserved its structure after the sintering process. The increase in fracture toughness for all series of composites has been noted (over 20% compared to reference samples). Detailed stereological analysis of the obtained microstructures also could determine the influence of the applied mill on the homogeneity of the final microstructure and the properties of obtained composites.

13.
BMJ Open ; 12(9): e060920, 2022 09 17.
Artículo en Inglés | MEDLINE | ID: mdl-36115674

RESUMEN

OBJECTIVES: To evaluate the feasibility and outcomes of an occupational therapy lifestyle intervention for adults living with chronic pain. DESIGN: This one-group pre-post interventional study investigated the feasibility and outcomes of the Redesign Your Everyday Activities and Lifestyle with Occupational Therapy (REVEAL(OT)) intervention targeting meaningful activities and lifestyle. SETTINGS: The occupational therapist-led intervention was added to standard multidisciplinary chronic pain treatment at a Danish pain centre. PARTICIPANTS: Of the 40 adult participants aged 18-64 (mean 46.6±10.9 years old, 85% females, chronic pain duration ≥3 months), there were 31 completers. INTERVENTION: Three feasibility rounds were carried out in 2019-2021. The intervention focused on meaningful activities, healthy eating habits and daily physical activity. Methods of didactical presentations, group discussions, personal reflection and experiential learning were used in the intervention composed both of individual and group sessions. OUTCOMES: Primary outcomes were predefined research progression criteria evaluated by the red-amber-green method. Secondary outcomes measured pre-post changes in health-related quality of life and occupational performance and satisfaction. RESULTS: The study demonstrated satisfactory programme adherence (77.5%), patients' self-perceived relevance (97%), timing and mode of delivery (97%) and assessment procedure acceptance (95%). No adverse events causing discontinuation occurred. Recruitment rate (n=5.7 monthly), retention (77.5%) and the fidelity of delivery (83.3%) needed improvement. We observed no improvement in health-related quality of life (mean=0.04, 95% CI -0.03 to 0.12) but positive change in occupational performance (mean=1.80, 95% CI 1.25 to 2.35) and satisfaction (mean=1.95, 95% CI 1.06 to 2.84). The participants reached the minimal clinically important difference for occupational performance (≥3.0 points in 13.8%) and satisfaction (≥3.2 points in 24.0%). CONCLUSIONS: The REVEAL(OT) intervention was feasible to deliver and beneficial for the participants' occupational performance and satisfaction. The interventions' recruitment, retention and delivery strategies need optimisation in a future definitive trial. TRIAL REGISTRATION NUMBER: NCT03903900.


Asunto(s)
Dolor Crónico , Terapia Ocupacional , Adulto , Ámbar , Dolor Crónico/terapia , Estudios de Factibilidad , Femenino , Humanos , Estilo de Vida , Masculino , Persona de Mediana Edad , Terapia Ocupacional/métodos , Calidad de Vida
14.
Psychiatr Pol ; 45(3): 405-17, 2011.
Artículo en Polaco | MEDLINE | ID: mdl-22232970

RESUMEN

In this review, the authors describe the Transcranial Doppler sonography technique (TCD). They also make an analysis of the up-to-date publications on the use of TCD in the studies on schizophrenia. The current studies show a promising potential of TCD. Its benefits are connected with high time-output, low-cost and only slightly invasive character. The difficulty of using TCD lies in the experience of the technician and the quality of the equipment. What should be kept in mind, is the fact that the data received in the TCD study is only an indirect indication of CNS activity. The research described here shows two potential directions of applying TCD to schizophrenia studies. One of them concerns the intensity of psychotic symptoms as well as the medications given on the changes in transcranial blood-flow. The second connects the search for cognitive function disorders and the activity of certain brain regions with the transcranial blood-flow changes resulting from them. In such a protocol of research, where TCD technique is simultaneously applied along with an evaluation through neuropsychological tests, one could speak of a functional transcranial study--fTCD. The studies mentioned here, have only a pilot character owing to a low number of subjects studied. However, a picture of subtle differences in cerebral blood flow of schizophrenic patients does appear. The use of TCD requires further, deeper studies with the participation of a larger group of patients, along with a neuropsychological tool application.


Asunto(s)
Encéfalo/irrigación sanguínea , Arterias Cerebrales/diagnóstico por imagen , Esquizofrenia/diagnóstico por imagen , Ultrasonografía Doppler Transcraneal/métodos , Velocidad del Flujo Sanguíneo , Lóbulo Frontal/irrigación sanguínea , Lóbulo Frontal/diagnóstico por imagen , Humanos , Arteria Cerebral Media/diagnóstico por imagen , Esquizofrenia/diagnóstico , Psicología del Esquizofrénico
15.
Materials (Basel) ; 14(8)2021 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-33924272

RESUMEN

In the present work, an oxygen hardening of near-ß phase Ti-13Nb-13Zr alloy in plasma glow discharge at 700-1000 °C was studied. The influence of the surface treatment on the alloy microstructure, tribological and micromechanical properties, and corrosion resistance is presented. A strong influence of the treatment on the hardened zone thickness, refinement of the α' laths and grain size of the bulk alloy were found. The outer hardened zone contained mainly an oxygen-rich Ti α' (O) solid solution. The microhardness and elastic modulus of the hardened zone decreased with increasing hardening temperature. The hardened zone thickness, size of the α' laths, and grain size of the bulk alloy increased with increasing treatment temperature. The wear resistance of the alloy oxygen-hardened at 1000 °C was about two hundred times, and at 700 °C, even five hundred times greater than that of the base alloy. Oxygen hardening also slightly improved the corrosion resistance. Tribocorrosion tests revealed that the alloy hardened at 700 °C was wear-resistant in a corrosive environment, and when the friction process was completed, the passive film was quickly restored. The results show that glow discharge plasma oxidation is a simple and effective method to enhance the micromechanical and tribological performance of the Ti-13Nb-13Zr alloy.

16.
Materials (Basel) ; 14(4)2021 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-33578629

RESUMEN

This study presents new findings related to the incorporation of MXene phases into ceramic. Aluminium oxide and synthesised Ti3C2 were utilised as starting materials. Knowing the tendency of MXenes to oxidation and degradation, particularly at higher temperatures, structural modifications were proposed. They consisted of creating the metallic layer on the Ti3C2, by sputtering the titanium or molybdenum. To prepare the composites, powder metallurgy and spark plasma sintering (SPS) techniques were adopted. In order to evaluate the effectiveness of the applied modifications, the emphasis of the research was placed on microstructural analysis. In addition, the mechanical properties of the obtained sinters were examined. Observations revealed significant changes in the MXenes degradation process, from porous areas with TiC particles (for unmodified Ti3C2), to in situ creation of graphitic carbon (in the case of Ti3C2-Ti/Mo). Moreover, the fracture changed from purely intergranular to cracking with high participation of transgranular mode, analogously. In addition, the results obtained showed an improvement in the mechanical properties for composites with Ti/Mo modifications (an increase of 10% and 15% in hardness and fracture toughness respectively, for specimens with 0.5 wt.% Ti3C2-Mo). For unmodified Ti3C2, enormously cracked areas with spatters emerged during tests, making the measurements impossible to perform.

17.
Polymers (Basel) ; 12(6)2020 May 29.
Artículo en Inglés | MEDLINE | ID: mdl-32486090

RESUMEN

With the development of 3D printing technology, there is a need to produce printable materials with improved properties, e.g., sliding properties. In this paper, the authors present the possibilities of producing composites based on biodegradable PLA with the addition of graphite. The team created composites with the following graphite weight contents: 1%, 2.5%, 5%, 7.5%, and 10%. Neat material was also subjected to testing. Tribological, mechanical, and chemical properties of the mentioned materials were examined. Measurements were also made after keeping the samples in ageing and climatic ovens. Furthermore, SEM observations of samples before and after friction tests were carried out. It was demonstrated that increasing graphite content caused a significant decrease in wear (PLA + 10% graphite had a wear rate three times lower than for a neat material). The addition of graphite did not adversely affect most of the other properties, but it ought to be noted that mechanical properties changed significantly. After conditioning in a climatic oven PLA + 10% graphite has (in comparison with neat material) 11% lower fracture stress, 47% lower impact strength, and 21% higher Young's modulus. It can be certainly stated that the addition of graphite to PLA is a step towards obtaining a material that is low-cost and suitable for printing sliding spare parts.

18.
Polymers (Basel) ; 11(12)2019 Dec 13.
Artículo en Inglés | MEDLINE | ID: mdl-31847165

RESUMEN

The main aim of the research was to compare the values of some thermal and electrical parameters obtained for a basalt fabric modified with the metal and ceramics coatings. The surface modification of basalt fabric was made by using a magnetron sputtering technique. Chrome and zirconium(IV) oxide coatings were deposited on the fabric surface. The thermal and electrical properties of selected fabrics were determined. In order to assess the comfort properties of fabrics, the thermal resistance of materials was analyzed. Instrumental color measurement was used for an assessment of the surface of modified and unmodified basalt fabric. Using a non-contact digital color imaging system, DigiEye, an original method of samples surface analysis was presented. As a result of research, the modification of basalt fabric surface for applications in a hot work environment enabled the improvement of thermal properties in relation to the references samples. The first level of protection against contact heat for a contact temperature of 100 °C was obtained for the zirconium(IV) oxide-modified basalt fabric. The first level of protection against radiant heat was obtained for all samples. The highest value for the heat radiant resistance was obtained for the chrome-modified basalt fabric.

19.
Adv Clin Exp Med ; 28(2): 203-210, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30085426

RESUMEN

BACKGROUND: The downfracture access to septoand turbinoplasty during maxillary osteotomy may be recommended in many cases. One or both of these laryngological interventions may be necessary when, after the patient's clinical evaluation, either an impaired function of nasal breathing or a deviated septum are present. The main postsurgical risk of the procedure is the destabilization of the cartilaginous septum position and its relation to adjacent anatomical structures, a change in the shape of the nose and the presence of a supratip break. OBJECTIVES: In this paper, the authors present their own experience in intranasal procedures, the relevant surgical techniques and possible complications, based on their own clinical findings and on a literature review. MATERIAL AND METHODS: The general aim of the study was to describe the key points and differences between septoand turbinoplasty performed classically and during Le Fort I osteotomy based on 90 orthognathic surgery patient cases. The procedures have been evaluated and compared regarding their advantages and disadvantages. RESULTS: Intraoperative downfracture of the maxilla facilitates the performance of various subsequent procedures in the regions of the nasal cavities and sinuses. Due to a very convenient access to the nasal cavities, it is possible to perform septoor turbinoplasty in patients with nasal airway breathing problems, a deviated septum, and in others. CONCLUSIONS: A combined effort of an otolaryngologist and a maxillofacial team improves the overall nasal breathing with a limited amount of complications. Endoscopy with low-dose computed tomography (CT) is a valuable diagnostic tool for measuring any breathing improvements in nasal capacity. Objective patient nasal breathing problems should be always investigated.


Asunto(s)
Cavidad Nasal/cirugía , Procedimientos Quirúrgicos Ortognáticos/métodos , Osteotomía Le Fort/métodos , Humanos , Maxilar , Tabique Nasal , Otorrinolaringólogos
20.
Ann Otol Rhinol Laryngol ; 128(9): 819-828, 2019 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31014081

RESUMEN

OBJECTIVE: The aim of the present study is to determine and compare the range of pH value in nasal and sinus cavities in vivo regarding the presence of bacteria colonizing sinonasal mucosa among healthy subjects. METHODS: The nasal pH value measurement using a portable pH meter (Dx-pH System, Restech) and the microbiological culture swab were taken from beneath the middle turbinate and in the sinus cavity in 39 healthy subjects during maxillary bone corrective osteotomy with the Le Fort I technique. RESULTS: The mean pH value (independently of sex, P = .441) in the healthy sinus cavity was statistically higher than in the nasal middle meatus: 7.96 (SD ± 0.29) versus 7.83 (SD ± 0.30) (P = .032). Forty-eight strains of bacteria were cultured from sinus maxillaries cavities-aerobic 36.8%, aerobic and anaerobic 52.6%, anaerobic only 10.5%-and 23 strains from the nasal meatus-aerobic 25%, aerobic and anaerobic 75%. A statistically significant correlation was found between the type and location of 8 microorganisms, especially Propionibacterium acnes, identified only in the sinus cavities. CONCLUSIONS: Differences in the pH value between the middle nasal meatus and the maxillary sinus are characteristic of healthy subjects and could be associated with the diverse bacterial flora. The role of bacteria Propionibacterium acnes seems to be crucial for the pH range and sinus flora in healthy subjects.


Asunto(s)
Seno Maxilar , Cavidad Nasal , Propionibacterium acnes/aislamiento & purificación , Adulto , Correlación de Datos , Femenino , Voluntarios Sanos , Humanos , Concentración de Iones de Hidrógeno , Masculino , Seno Maxilar/química , Seno Maxilar/microbiología , Microbiota , Persona de Mediana Edad , Cavidad Nasal/química , Cavidad Nasal/microbiología
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