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1.
J Orthop Surg Res ; 17(1): 303, 2022 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-35672754

RESUMO

BACKGROUND: Monteggia fractures and Monteggia-like lesions result after severe trauma and have high complication rates. Preliminary biomechanical studies suggested a correlation between ulnar fracture localization and clinical result. OBJECTIVES: Key objective was to evaluate whether the site of the ulnar fracture can be correlated to clinical outcome after open reduction and internal stabilization. METHODS: In a retrospective, monocentric study 35 patients who underwent surgical treatment after suffering a Monteggia injury or Monteggia-like lesion were included. Fractures were classified according to Bado and Jupiter, the site of the fracture location at the proximal ulna and regarding the potential accompanying ligamentary injury. In a follow-up examination validated patient-reported outcome measures and functional parameters were evaluated. Furthermore, treatment strategy and complications were analysed. RESULTS: Mean patient age was 51.9 years (± 18.0). 69% were females (n = 24). Follow-up took place after 50.5 months (± 22.1). Fractures were classified according to Bado (I:2, II:27, III:4, IV:2). Bado II-fractures were further classified according to Jupiter (A:7, B:16, C:3, D:1). Cases were divided into subgroups depending upon the distance of the ulnar fracture site in respect to its distal endpoint (A: < 7 cm and B: > 7 cm). Average overall MEPS was 84.1 (± 19.0). Oxford elbow score and DASH were 37.2 (± 10.5) and 20.4 (± 20.5). Average extension capability reached - 7° (± 7.5). Mean flexion was 134.8° (± 19.7). Average pain according to visual analogue scale was 1.6 (± 1.9). We found no differences between the subgroups regarding the PROMs. Subgroup A displayed a worse extension capability (p = 0.027) and patients were significantly older (p < 0.01). Comparing patients with and without fracture of the radial head, we observed no differences. Patients with an accompanying injury of the coronoid process displayed higher pain levels (p = 0.011), a worse functionality (p = 0.027) and overall lower scoring in PROM. CONCLUSION: The presented results suggest that in Monteggia fractures and Monteggia-like lesions, the localization of the ulna fracture can give a hint for its postoperative outcome. However, we could not confirm the hypothesis of an increasing instability in ulnar fractures located further distally (high severity of the potential ligamentous injury). Intraarticular fractures or injuries with a close relation to the joint have a worse prognosis, especially if the coronoid process is injured. Trial registration Registration was done with ClinicalTrials.gov under NCT05325268.


Assuntos
Lesões no Cotovelo , Fratura de Monteggia , Fraturas da Ulna , Adulto , Idoso , Feminino , Fixação Interna de Fraturas/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Fratura de Monteggia/diagnóstico por imagem , Fratura de Monteggia/cirurgia , Dor , Medidas de Resultados Relatados pelo Paciente , Amplitude de Movimento Articular , Estudos Retrospectivos , Resultado do Tratamento , Fraturas da Ulna/cirurgia
2.
Eur J Med Res ; 24(1): 33, 2019 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-31594540

RESUMO

BACKGROUND: Patients with a simple transversal fracture of the olecranon are often treated with a tension band wiring (TBW), because it is known as a biomechanically appropriate and cost-effective procedure. Nevertheless, the technique is in detail more challenging than thought, resulting in a considerable high rate of implant-related complications like k-wire loosening and soft tissue irritation. In the literature, a distinction is generally only made between transcortical (bi-) and intramedullary (mono-) fixation of the wires. There is the additional possibility to fix the proximal bent end of k-wire in the cortex of the bone and thus create a tricortical fixation. The present study investigates the effectiveness of bi- and tricortical k-wire fixation in a biomechanical approach. METHODS: TBW of the olecranon was performed at 10 cadaver ulnas from six donors in a usual manner and divided into two groups: In group 1, the k-wire was inserted by bicortical fixation (BC), and in group 2, a tricortical fixation (TC) was chosen. Failure behavior and maximum pullout strength were assessed and evaluated by using a Zwick machine. The statistical evaluation was descriptive and with a paired t test for the evaluation of significances between the two techniques. RESULTS: The average age of the used donors was 81.5 ± 11.5 (62-92) years. Three donors were female, and three were male. Ten k-wires were examined in BC group and 10 in the TC group. The mean bone density of the used proximal ulnas was on average 579 ± 186 (336-899) HU. The maximum pullout strength was 263 ± 106 (125-429) N in the BC group and increased significantly in the TC group to 325 ± 102 (144-466) N [p = .005]. CONCLUSION: This study confirms for the first time biomechanical superiority of tricortical k-wire fixation in the olecranon when using a TBW and may justify the clinical use of this method.


Assuntos
Fios Ortopédicos/normas , Fixação Interna de Fraturas/instrumentação , Fraturas Ósseas/cirurgia , Olécrano/lesões , Olécrano/cirurgia , Idoso , Idoso de 80 Anos ou mais , Fenômenos Biomecânicos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
3.
Bone Joint Res ; 8(2): 41-48, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30915209

RESUMO

OBJECTIVES: Intra-articular injections of local anaesthetics (LA), glucocorticoids (GC), or hyaluronic acid (HA) are used to treat osteoarthritis (OA). Contrast agents (CA) are needed to prove successful intra-articular injection or aspiration, or to visualize articular structures dynamically during fluoroscopy. Tranexamic acid (TA) is used to control haemostasis and prevent excessive intra-articular bleeding. Despite their common usage, little is known about the cytotoxicity of common drugs injected into joints. Thus, the aim of our study was to investigate the effects of LA, GC, HA, CA, and TA on the viability of primary human chondrocytes and tenocytes in vitro. METHODS: Human chondrocytes and tenocytes were cultured in a medium with three different drug dilutions (1:2; 1:10; 1:100). The following drugs were used to investigate cytotoxicity: lidocaine hydrochloride 1%; bupivacaine 0.5%; triamcinolone acetonide; dexamethasone 21-palmitate; TA; iodine contrast media; HA; and distilled water. Normal saline served as a control. After an incubation period of 24 hours, cell numbers and morphology were assessed. RESULTS: Using LA or GC, especially triamcinolone acetonide, a dilution of 1:100 resulted in only a moderate reduction of viability, while a dilution of 1:10 showed significantly fewer cell counts. TA and CA reduced viability significantly at a dilution of 1:2. Higher dilutions did not affect viability. Notably, HA showed no effects of cytotoxicity in all drug dilutions. CONCLUSION: The toxicity of common intra-articular injectable drugs, assessed by cell viability, is mainly dependent on the dilution of the drug being tested. LA are particularly toxic, whereas HA did not affect cell viability.Cite this article: P. Busse, C. Vater, M. Stiehler, J. Nowotny, P. Kasten, H. Bretschneider, S. B. Goodman, M. Gelinsky, S. Zwingenberger. Cytotoxicity of drugs injected into joints in orthopaedics. Bone Joint Res 2019;8:41-48. DOI: 10.1302/2046-3758.82.BJR-2018-0099.R1.

4.
Eur J Med Res ; 23(1): 43, 2018 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-30219102

RESUMO

BACKGROUND: In the treatment of lateral epicondylitis (LE), the role of a new dynamic wrist orthosis is unclear. PATIENTS AND METHODS: Patients suffering from a LE longer than 3 months were multicentrically and prospectively randomized into a physiotherapeutic group (PT group) and in a physiotherapy group plus wrist orthosis (PT + O group). Physiotherapy consisted of daily eccentric strengthening exercises under initial professional supervision. Inclusion criteria were a Placzek score greater than 4. Exclusion criteria were previous surgery, rheumatic arthritis, elbow instability, radicular symptoms, higher-grade extensor tendon rupture, or cervical osteoarthritis. The clinical evaluation was performed after 12 weeks and 12 months. The Patient-Rated Tennis Elbow Evaluation (PRTEE) scale, Placzek Score, the pain rating (VAS), range of motion and the Subjective Elbow Score were evaluated. RESULTS: Of the initially 61 patients, 31 were followed up after 12 weeks and 22 after 12 months. Twenty-nine patients (43%) were male, the mean age was 46, and 44 patients (66%) had the right elbow involved. At 12 weeks, there was a pain reduction on the VAS in both groups (PT + O: 6.5-3.7 [p = .001]; PT: 4.7-4.1 [p = .468]), albeit it was only significant for the PT + O group. At 12 months, reduction was significant in both groups (PT + O: 1.1 [p = .000]; PT: 1.3 [p = .000]). The painless maximum hand strength in kg improved in both groups significant after 3 and 12 months. The Placzek score was reduced from 8.25 to 3.5 [p = .001] after 12 weeks for the PT + O group and from 8.1 to 3.8 [p = .000] in the PT group, as well as after 12 months in the PT + O group to 0 [p = .000] and in the PT group to 2.0 [p = .000]. The PRTEE improved in both groups after 12 weeks (PT + O: 52.8--31.3 [p = .002]; PT: 48.6-37.6 [p = .185]) and 12 months (PT + O: 16.15 [p = .000]; PT: 16.6 [p = .000]), although the reduction at 12 weeks was not significant for the PT group. CONCLUSION: The elbow orthosis appears to accelerate the healing process with respect to the PRTEE and pain on the VAS (12 weeks follow-up), although there is an adjustment after 12 months in both groups and a significant improvement of symptoms is achieved in all endpoints.


Assuntos
Aparelhos Ortopédicos , Dor/prevenção & controle , Modalidades de Fisioterapia , Cotovelo de Tenista/terapia , Punho , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Recuperação de Função Fisiológica , Cotovelo de Tenista/fisiopatologia
5.
Oper Orthop Traumatol ; 29(2): 138-148, 2017 Apr.
Artigo em Alemão | MEDLINE | ID: mdl-28331961

RESUMO

OBJECTIVES: Correcion of elbow joint deformities that usually develop secondary to direct or indirect trauma of the arm or elbow with subsequent inadequate healing and consecutive axial/rotational malalignment and may be associated with cosmetic or functional deficits of the arm. INDICATIONS: Relevant malalignment of the arm axis with corresponding cosmetic or functional deficits for the patient. CONTRAINDICATIONS: Pre-existing degenerative and chronic inflammatory changes. SURGICAL TECHNIQUE: Generally, two-dimensional supracondylar open or closed wedge osteotomies are used. In the presence of a three-dimensional deformity (with rotational component), an additional derotational correction is necessary. Extra-articular deformities following extension fractures should be treated preferably with an open wedge osteotomy, extra-articular deformities of flexion fractures with a closed wedge osteotomy. Valgus/varus deformities may also require a closed/open wedge osteotomy primarily through a dorsal or alternatively radial approach. POSTOPERATIVE MANAGEMENT: The arm should be immobilized with a brachial cast splint for 2-3 weeks, with passive exercises of the elbow starting on postoperative day 7. RESULTS: In general, the results for a three-dimensional osteotomy of the distal humerus are expected to be good to very good. Only in rare cases (2.5%) is a mostly transient irritation of the ulnar nerve observed.


Assuntos
Articulação do Cotovelo/anormalidades , Articulação do Cotovelo/cirurgia , Deformidades Articulares Adquiridas/cirurgia , Osteotomia/métodos , Osteotomia/reabilitação , Procedimentos de Cirurgia Plástica/métodos , Procedimentos de Cirurgia Plástica/reabilitação , Medicina Baseada em Evidências , Humanos , Deformidades Articulares Adquiridas/reabilitação , Resultado do Tratamento , Lesões no Cotovelo
6.
J Biomater Sci Polym Ed ; 27(10): 917-36, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27109607

RESUMO

One possibility to improve the mechanical properties after tendon ruptures is augmentation with a scaffold. Based on wet spinning technology, chitosan fibres were processed to a novel pure high-grade multifilament yarn with reproducible quality. The fibres were braided to obtain a 3D tendon scaffold. The CS fibres and scaffolds were evaluated biomechanically and compared to human supraspinatus (SSP) tendons. For the cytobiological characterization, in vitro cell culture experiments with human mesenchymal stem cells (hMSC) were performed. Three types of 3D circular braided scaffolds were fabricated. Significantly, higher ultimate stress values were measured for scaffold with larger filament yarn, compared to scaffold with smaller filament yarn. During cultivation over 28 days, the cells showed in dependence of isolation method and/or donor a doubling or tripling of the cell number or even a six-fold increase on the CS scaffold, which was comparable to the control (polystyrene) or in the case of cells obtained from human biceps tendon even higher proliferation rates. After 14 days, the scaffold surface was covered homogeneously with a cell layer. In summary, the present work demonstrates that braided chitosan scaffolds constitute a straightforward approach for designing tendon analogues, maintaining important flexibility in scaffold design and providing favourable mechanical properties of the resulting construct.


Assuntos
Quitosana/química , Células-Tronco Mesenquimais/citologia , Tendões/citologia , Engenharia Tecidual , Alicerces Teciduais/química , Materiais Biocompatíveis/química , Adesão Celular , Técnicas de Cultura de Células , Proliferação de Células , Sobrevivência Celular , Humanos , Microscopia Eletrônica de Varredura , Poliestirenos/química
7.
J Thromb Haemost ; 11(4): 651-9, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23347087

RESUMO

BACKGROUND: Bleeding complications are common side effects of vitamin-K antagonist (VKA) therapy. Data on the in-hospital management and outcomes of these bleeding events are scarce and information is mostly derived from trial cohorts. OBJECTIVES: The objective was to collect data on the management and clinical outcome of hospitalizations owing to VKA-related bleeding in real-world practice. PATIENTS AND METHODS: We performed a multicenter observational cohort study involving 21 secondary and tertiary care hospitals in the administrative district Dresden, Saxony, Germany throughout the year 2005. All consenting patients presenting with VKA-related bleeding complications were included. No exclusion criteria applied. Data were collected at admission, at discharge and at 90 days to evaluate resource consumption, length of hospital stay and risk factors for in-hospital- and 3-month mortality. RESULTS: Two hundred and ninety patients were included (median age 74 years; 50.7% male). The main indications for VKA therapy were atrial fibrillation (63.4%), prior thromboembolism (18.6%) and mechanical heart valves (11.4%), and most common bleeding localizations were large hematoma (23.1%), upper gastrointestinal (GI) tract (17.9%) and intracranial bleeding (14.1%). On hospital admission, the median International Normalized Ratio (INR) was 3.0 (range 0.9-12.5, interquartile range [IQR] 2.1-3.9). In-hospital mortality was 7.6% with impaired renal function as the most relevant risk factor. At 90 days mortality was 14.1% and 15.3% of survivors were help-dependent. CONCLUSIONS: VKA-related bleeding leading to hospitalization is associated with long hospitalization, relevant resource utilization, high mortality or persistent sequlae. Patient-related factors such as impaired renal function, chronic cardiac or pulmonary disease and dementia are predictive of in-hospital and 3-month mortality.


Assuntos
Anticoagulantes/efeitos adversos , Hemorragia/induzido quimicamente , Hospitalização , Vitamina K/antagonistas & inibidores , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Feminino , Humanos , Coeficiente Internacional Normatizado , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
8.
Biol Sport ; 30(4): 311-5, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24795500

RESUMO

The purpose of the research was to evaluate the efficiency of body balance regulation in the elderly and verify whether physical activity in adolescence could influence later physical efficiency. Research was carried out on 62 persons aged between 65 and 96 years of age. Fifty people declared that they undertook physical activity in adolescence, while 12 reported no activity. Stabilographic examinations were performed during trials with open and closed eyes on a horizontally situated platform tilted forward and backward. The centre-of-pressure (COP) path length, sway range area and centre-of-pressure velocity (COP velocity) were assessed. The safety margin when a person leans forward and backward was evaluated as well. On a horizontally situated platform, exclusion of visual control in most of the examined participants resulted in a significant increase in values of examined parameters. Tilting the platform caused in both groups an increase in values of all the parameters. These changes were more visible when a trial with eyes closed was performed and the group of active people obtained better results. These people were also able to use the support area more effectively when changing the position of the body. It was found that body balance disorder affects more often elderly people who were less active in adolescence and that with age visual balance control dominates the proprioceptive one. This means that physical activity directed towards, among other things, forming and improving the body balance regulation system is needed at an early age.

9.
J Am Chem Soc ; 130(30): 9984-93, 2008 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-18598033

RESUMO

The measurements of electron work function were applied for in situ monitoring of the charge transfer during oxidation and reduction for well-defined titanium dioxide, TiO 2, at room temperature. The TiO 2 specimen was initially standardized at 1173 K in the gas phase of controlled oxygen activity, at p(O 2) = 10 Pa, and then cooled down in the same gas phase. The work function changes were monitored during oxidation at room temperature at p(O 2) = 75 kPa and subsequent reduction at p(O 2) = 10 Pa. It is shown that oxidation of TiO 2 at room temperature results in fast oxygen chemisorption, involving initially the formation of singly ionized molecular oxygen species, followed by the formation of singly ionized atomic oxygen species, and subsequent slow oxygen incorporation. Although all these processes lead to work function increase, the components of the work function changes related to the individual processes may be distinguished based on different kinetics. The obtained work function data indicate that oxidation results in rapid surface coverage with singly ionized molecular oxygen species, which are subsequently dissociated leading to the formation of singly ionized atomic species. The related chemisorption equilibria are established within 2 and 5 h, respectively. Oxygen incorporation leads to slow work function changes, which achieve a maximum within 100 h. The determined work function data were assessed by using a theoretical model that describes the electrical effects related to different mechanisms of TiO 2 oxidation. The work function data indicate that oxygen incorporation leads to structural changes of the outermost surface layer resulting, in consequence, in a change of the external work function component. Reimposition of the initial gas phase, p(O 2) = 10 Pa, leads to partial desorption of weakly adsorbed molecular species formed during oxidation.

10.
J Phys Chem B ; 110(45): 22447-54, 2006 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-17091986

RESUMO

The present work reports the electrical conductivity and thermoelectric power for Nb-doped TiO(2) at elevated temperatures (1073-1298 K) in the gas phase of controlled oxygen activity, 10(-14) Pa < p(O(2)) < 75 kPa. It is shown that in reduced conditions the Nb-doped TiO(2) exhibits metallic-type conductivity. This finding paves the way for the development of high-performance photoelectrodes with substantially reduced internal energy losses during charge transport. The present work also determined the equilibrium constant for the formation of oxygen vacancies and titanium vacancies for Nb-doped TiO(2).

11.
J Phys Chem B ; 110(45): 22455-61, 2006 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-17091987

RESUMO

The present work reports isothermal gas/solid equilibration kinetics for Nb-doped TiO(2) (0.65 atom %) at elevated temperatures (1073-1298 K) within narrow ranges of oxygen activity spanning between 10(-13) Pa and 75 kPa. The equilibration kinetics were monitored using electrical conductivity measurements. The kinetic data were used to determine the chemical diffusion coefficient (D(chem)). D(chem) as a function of p(O(2)) exhibits a complex dependence, which is considered in terms of defect disorder and the related concentrations of electronic charge carriers. The activation energy of D(chem) in the p(O(2)) range 10 Pa < p(O(2)) < 75 kPa varies in the range 88.0-98.2 kJ/mol. It is important to note that the chemical diffusion coefficient in strongly reduced conditions [p(O(2)) = 10(-9) Pa] exhibits a negative temperature dependence of D(chem) (-67.2 kJ/mol). This finding indicates that under these conditions transport in a chemical potential gradient is consistent with metallic charge transport.

12.
J Phys Chem B ; 110(43): 21560-7, 2006 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-17064107

RESUMO

The present work derived defect disorder diagram representing the effect of oxygen activity on the concentration of both ionic and electronic defects for undoped TiO2. This diagram was determined using the equilibrium constants derived in the present work, including (i) the intrinsic electronic equilibrium constant, (ii) the equilibrium constant for the formation of oxygen vacancies, and (iii) equilibrium constant for the formation of titanium vacancies. These equilibrium constants are consistent with three properties determined independently, including: electrical conductivity, thermoelectric power and change of mass determined by thermogravimetry. The derived defect disorder diagram may be used for tailoring semiconducting properties of TiO2 that are desired for specific applications through the selection of optimized processing conditions.

13.
J Phys Chem B ; 110(37): 18492-5, 2006 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-16970476

RESUMO

The mechanism of photoreactivity between the TiO(2) surface and H(2)O, and the related charge transfer, is considered in terms of both collective and local properties. It is shown that the effective charge transfer between TiO(2) and water requires the presence of surface active sites that are able to provide electron holes to adsorbed water molecules. Titanium vacancies located at or near the surface are identified as the active sites for water adsorption leading to the formation of an active complex and resulting, in consequence, in water splitting. A model of the photoreactivity between the TiO(2) surface and water is proposed. This model indicates that the photoreactivity of the TiO(2)-based photoelectrode may be enhanced through imposition of the surface active sites (Ti vacancies) in a controlled manner by surface engineering.

14.
J Phys Chem B ; 110(33): 16270-82, 2006 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-16913753

RESUMO

The present work reports the electrical properties of high-purity single-crystal TiO(2) from measurements of the electrical conductivity in the temperature range 1073-1323 K and in gas phases of controlled oxygen activities in the range 10(-13) to 10(5) Pa. The effect of the oxygen activity on the electrical conductivity indicates that oxygen vacancies are the predominant defects in the studied ranges of temperature and oxygen activities. The electronic and ionic lattice charge compensations were revealed at low and high oxygen activities, respectively. The determined semiconducting quantities include: the activation energy of the electrical conductivity (E(sigma) = 125-205 kJ.mol(-1)), the activation energies of the electrical conductivity components associated with electrons (E(n) = 218 kJ.mol(-1)), electron holes (E(p) = 34 kJ.mol(-1)), and ions (E(i) = 227 kJ.mol(-1)), and the enthalpy of motion for electronic defects (DeltaH(m) = 4 kJ/mol). The electrical conductivity data are considered in terms of the components related to electrons, holes, and ions. The obtained data allow the determination of the n-p demarcation line in terms of temperature and oxygen activities. The band gap determined from the electronic component of the electrical conductivity is 3.1 eV.


Assuntos
Condutividade Elétrica , Titânio/química , Cristalização , Gases/química
15.
J Phys Chem B ; 110(33): 16283-91, 2006 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-16913754

RESUMO

The present work reports the thermoelectric power of high-purity single-crystal TiO(2) in the temperature range 1073-1323 K and in gas phases of controlled oxygen activities, p(O(2)), in the range 10(-13) to 7.5 x 10(4) Pa. The thermoelectric power versus log p(O(2)) dependence for strongly reduced TiO(2) at p(O(2)) < 10(-5) Pa may be approximated by a slope of 1/6, which is consistent with the defect disorder governed by electronic charge compensation of oxygen vacancies. The thermoelectric power data confirm that oxygen vacancies are the predominant ionic defects. These data indicate that TiO(2) at high p(O(2)) exhibits p-type properties. It is shown that the p(O(2)) related to the n-p transition increases with increase of temperature.

16.
J Phys Chem B ; 110(33): 16292-301, 2006 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-16913755

RESUMO

The equilibration kinetics of high-purity single-crystal TiO(2) were monitored using measurements of electrical conductivity in the temperature range 1073-1323 K and oxygen activity, p(O(2)), range 10(-13) to 75 kPa. The kinetics data were used to determine the chemical diffusion coefficient (D(chem)) within narrow ranges of p(O(2)). There was observed a complex effect of the p(O(2)) on the D(chem), which exhibits a maximum at the n-p transition. The effect of the p(O(2)) on the D(chem) was discussed in terms of the defect disorder and the related semiconducting properties. The activation energy of the D(chem), which also varies with the p(O(2)), exhibits a maximum at p(O(2)) = approximately 10(4) Pa (143 kJ/mol).

17.
J Phys Chem B ; 110(33): 16302-8, 2006 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-16913756

RESUMO

Measurements of both electrical conductivity and thermoelectric power were used to monitor the equilibration kinetics of undoped single-crystal TiO(2) during prolonged oxidation at 1123 and 1323 K and p(O(2)) = 75 kPa. Two kinetics regimes were revealed: kinetics regime I (rapid kinetics), which is rate-controlled by the transport of oxygen vacancies, and kinetics regime II (slow kinetics), which is rate-controlled by the transport of titanium vacancies. The incorporation of titanium vacancies allows undoped p-type TiO(2) to be processed in a controlled manner. The kinetics data were used to determine the chemical diffusion coefficient (D(chem)) associated with the transport of titanium vacancies, which is equal to D(chem) = 8.9 x 10(-14) m(2) s(-1) and D(chem) = 9.3 x 10(-15) m(2) s(-1) at 1323 and 1123 K, respectively.

18.
Ortop Traumatol Rehabil ; 4(4): 498-502, 2002 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-17679887

RESUMO

This article discusses the value of photogrametric testing in the comprehensive diagnosis of posture defects. Attention is drawn to the fact that this mode of testing, which in essence provides no information about the posture of the body as a whole, can only be regarded at present as an auxiliary test. The authors emphasize the fact that the basis for diagnosing locomotor dysfunction continues to be a thorough physical examination using classical techniques.

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