Estimation of the elastic modulus and the work of adhesion of soft materials using the extended Borodich–Galanov (BG) method and depth sensing indentation

© 2018 Elsevier Ltd The depth-sensing indentation (DSI) is currently one of the main experimental techniques for studying elastic properties of materials of small volumes. Usually DSI tests are performed using sharp pyramidal indenters and the load-displacement curves obtained are used for estimations of elastic moduli of materials, while the curve analysis for these estimations is based on the assumptions of the Hertz contact theory of non-adhesive contact. The Borodich–Galanov (BG) method provides an alternative methodology for estimations of the elastic moduli along with estimations of the work of adhesion of the contacting pair in a single experiment using the experimental DSI data for spherical indenters. The method assumes fitting the experimental points of the load-displacement curves using a dimensionless expression of an appropriate theory of adhesive contact. Earlier numerical simulations showed that the BG method was robust. Here first the original BG method is modified and then its accuracy in the estimation of the reduced elastic modulus is directly tested by comparison with the results of conventional tensile tests. The method modification is twofold: (i) a two-stage fitting of the theoretical DSI dependency to the experimental data is used and (ii) a new objective functional is introduced which minimizes the squared norm of difference between the theoretical curve and the one used in preliminary data fitting. The direct experimental validation of accuracy and robustness of the BG method has two independent steps. First the material properties of polyvinyl siloxane (PVS) are determined from a DSI data by means of the modified BG method; and then the obtained results for the reduced elastic modulus are compared with the results of tensile tests on dumbbell specimens made of the same charge of PVS. Comparison of the results of the two experiments showed that the absolute minimum in relative difference between individual identified values of the reduced elastic modulus in the two experiments was 3.80%; the absolute maximum of the same quantity was 27.38%; the relative difference in averaged values of the reduced elastic modulus varied in the range 16.20.. 17.09% depending on particular settings used during preliminary fitting. Hence, the comparison of the results shows that the experimental values of the elastic modulus obtained by the tensile tests are in good agreement with the results of the extended BG method. Our analysis shows that unaccounted factors and phenomena tend to decrease the difference in the results of the two experiments. Thus, the robustness and accuracy of the proposed extension of the BG method has been directly validated

Symptoms in different severity degrees of bruxism: a cross-sectional study

Objective: The aim of the present study was to evaluate symptoms of the muscle pain, sleep quality, oral health, anxiety, stress and depression in individuals with different severity degrees of bruxism. Methods: Seventy-two individuals with bruxism were enrolled in the study, classified into: moderate (n=25) and severe (n=47) bruxism. Pain intensity was assessed using the Visual Analogical Scale, pain threshold with algometer, sleep quality by the Pittsburgh Sleep Quality Index, oral health by the Oral Health Impact Profile, anxiety by the State-Trait Anxiety Inventory, stress by the Perceived Stress Scale and depression using the Beck Depression Inventory. The significance level considered was 5%. Results: The results showed that individuals with severe bruxism presented greater muscle pain intensity, sleep disorder, worse oral health, high anxiety level and dysphoria with statistically significant differences (pObjetivo: Avaliar sintomas de dor muscular, qualidade de sono, saúde bucal, ansiedade, estresse e depressão em indivíduos com diferentes graus de severidade do bruxismo. Métodos: Setenta e dois indivíduos com bruxismo participaram do estudo e foram classificados com bruxismo moderado (n=25) e severo (n=47). A intensidade da dor foi avaliada pela Escala Visual Analógica, limiar de dor com o algômetro, qualidade de sono pelo Índice de Qualidade de Sono de Pittsburgh, saúde bucal pelo Perfil de Impacto de Saúde Bucal, ansiedade pelo Inventário de Ansiedade Traço-Estado, estresse pela Escala de Estresse Percebido e depressão pelo Inventário de Depressão de Beck. O nível de significância considerado foi 5%. Resultados: Os resultados demonstraram que indivíduos com bruxismo severo apresentaram maior intensidade de dor muscular, distúrbio do sono, pior qualidade de saúde bucal, elevado grau de ansiedade e disforia, com diferenças estatisticamente significantes (p;0,05). Conclusão: Os dados sugerem que indivíduos com bruxismo severo tem sintomas mais intensos. Eles apresentam maior intensidade de dor muscular, alterações na qualidade do sono e saúde bucal, ansiedade e depressão do que indivíduos com bruxismo moderado. Porém, ambos apresentam similaridade no estresse.Objetivo: Evaluar los síntomas dolor muscular, calidad de sueño, salud bucal, ansiedad, estrés y depresión en sujetos con diferentes niveles de gravedad del bruxismo. Método: Participaron del estudio 72 personas con bruxismo, clasificado según los niveles moderado (n=25) y grave (n=47). Se evaluaron la intensidad del dolor mediante la Escala Visual Analógica, umbral de dolor con algómetro, la calidad de sueño por el Índice de Calidad de Sueño de Pittsburgh, la salud bucal mediante el Perfil del Impacto de Salud Bucal, la ansiedad por el Inventario de Ansiedad Rasgo-Estado, el estrés mediante la Escala de Estrés Percibido y la depresión por el Inventario de Depresión de Beck. Se consideró el nivel de significación de 5%. Resultados: Los sujetos con bruxismo grave presentaron más intensamente dolor muscular, trastorno de sueño, peor calidad de salud bucal, alto grado de ansiedad y disforia, con diferencias estadísticamente significativas (p;0,05). Conclusión: Los datos mostraron que los sujetos con bruxismo grave sufren síntomas más intensos. A pesar de sufrir síntomas más intensos de dolor muscular, calidad de sueño y salud bucal alterada, ansiedad y depresión que los sujetos con bruxismo moderado, el estrés está presente en los dos niveles de bruxismo

Influence of Short-Term Glucocorticoid Therapy on Regulatory T Cells In Vivo

Background: Pre- and early clinical studies on patients with autoimmune diseases suggested that induction of regulatory T(Treg) cells may contribute to the immunosuppressive effects of glucocorticoids(GCs). Objective: We readdressed the influence of GC therapy on Treg cells in immunocompetent human subjects and naı¨ve mice. Methods: Mice were treated with increasing doses of intravenous dexamethasone followed by oral taper, and Treg cells in spleen and blood were analyzed by FACS. Sixteen patients with sudden hearing loss but without an inflammatory disease received high-dose intravenous prednisolone followed by stepwise dose reduction to low oral prednisolone. Peripheral blood Treg cells were analyzed prior and after a 14 day GC therapy based on different markers. Results: Repeated GC administration to mice for three days dose-dependently decreased the absolute numbers of Treg cells in blood (100 mg dexamethasone/kg body weight: 2.861.86104 cells/ml vs. 336116104 in control mice) and spleen (dexamethasone: 2.861.96105/spleen vs. 956226105/spleen in control mice), which slowly recovered after 14 days taper in spleen but not in blood. The relative frequency of FOXP3+ Treg cells amongst the CD4+ T cells also decreased in a dose dependent manner with the effect being more pronounced in blood than in spleen. The suppressive capacity of Treg cells was unaltered by GC treatment in vitro. In immunocompetent humans, GCs induced mild T cell lymphocytosis. However, it did not change the relative frequency of circulating Treg cells in a relevant manner, although there was some variation depending on the definition of the Treg cells (FOXP3+: 4.061.5% vs 3.461.5%*; AITR+: 0.660.4 vs 0.560.3%, CD127low: 4.061.3 vs 5.063.0%* and CTLA4+: 13.8611.5 vs 15.6612.5%; * p,0.05). Conclusion: Short-term GC therapy does not induce the hitherto supposed increase in circulating Treg cell frequency, neither in immunocompetent humans nor in mice. Thus, it is questionable that the clinical efficacy of GCs is achieved by modulating Treg cell numbers

NK cells in children with acute lymphoblastic leukemia and non-Hodgkin lymphoma after cessation of intensive chemotherapy

Intensive, combination chemotherapy for malignant diseases causes a profound immunosuppression, which persists for the whole treatment period and after its completion. Impairment of the NK cells status may increase the risk of severe, disseminated infections and cancer. The aim of the study was the investigation of recovery of NK cells after cessation of intensive chemotherapy in children with acute lymphoblastic leukemia (ALL) and non-Hodgkin lymphoma (NHL). The number of CD3 - CD16+CD56+ cells in peripheral blood and NK cell cytotoxic activity were assessed in 23 children with ALL and 7 children with NHL at 2 weeks and 12 months after the cessation of intensive chemotherapy and in 15 healthy subjects. Absolute leukocyte, lymphocyte and NK cell counts and the percentage of NK cells in children with ALL were significantly lower than in control subjects both at 2 weeks and 12 months after intensive treatment. Additionally, the absolute numbers of leukocytes and lymphocytes decreased significantly after 12 months of observations in comparison to the initial time-point. In children with non-Hodgkin lymphoma at 2 weeks and 12 months after intensive treatment only absolute lymphocyte counts were significantly lower than values in healthy children. The absolute number, the percentage and cytotoxic activity of NK cells were comparable with values in the control group both at the initial and at the last time-point. The occurrence of infections during the 12 months of observations in patients with ALL were higher than in children with NHL and as many as eight of them were hospitalized because of severe infections. The differences between the ALL and NHL patients may be connected with the milder immunosuppressive effect of chemotherapy in the non-Hodgkin lymphoma since the children recovered from acute lymphoblastic leukemia remain with persistent defect of NK cells. It is then recommended that ALL children should be supervised with respect to an increased susceptibility to infections

Great potential of ultrasound elastography for the assessment of the masseter muscle in patients with temporomandibular disorders. A systematic review

Objective: To summarize the available evidence on the use of elastography in the assessment of the masseter muscle in healthy individuals and patients with masseter muscle disorders.Methods: Systematic literature review has been performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines.Results: 16 of 142 studies identified were analyzed. Elastography was used in seven studies. Heterogeneity was observed in terms of study protocols, devices, patients, units of measure, and results. Elasticity values showed a correlation between the left and right masseter muscle side in healthy people, but not in patients with temporomandibular disorders (TMDs). Elasticity values increased in TMD and were correlated with the severity of TMD symptoms. Phantom studies proved the high reliability of elastography.Conclusion: Elastography is a promising tool for the assessment of the masseter muscle elasticity, but the evidence is insufficient. Studies on larger groups are needed to determine the accuracy of elastography to characterize masticatory muscle disorders.Radiolog

Homeostatic repopulation by CD28-CD8+ T cells in alemtuzumab-depleted kidney transplant recipients treated with reduced immunosuppression.

Alemtuzumab (CAMPATH-1H) is a depleting agent introduced recently in transplantation and often used with reduced maintenance immunosuppression. In the current study we investigated the immune response of 13 kidney allograft recipients treated with alemtuzumab followed by weaned immunosuppression with reduced dose of mycophenolate mofetil (MMF) and tacrolimus. Tacrolimus was switched to sirolimus at 6 months and MMF withdrawn at 12 months after transplantation. We found that after alemtuzumab induction the recovery of CD8(+) T cells was much faster than that of CD4(+) T cells. It was complete 6 months posttransplant while CD4(+) T cells did not fully recover even 15 months posttransplant. Repopulating CD8(+) T cells were mainly of immunosenescent CD28(-)CD8(+) phenotype. In a series of in vitro experiments we showed that CD28(-)CD8(+) T cells might suppress proliferation of CD4(+) T cells. There were three successfully treated acute rejections during the study (first at +70 day, two others +12 months) that occurred in patients with the lowest level of CD28(-)CD8(+) T cells. We hypothesize that expanded CD28(-)CD8(+) T cells might compete for 'immune space' with CD4(+) T cells suppressing their proliferation and therefore delaying CD4(+) T-cells recovery. This delay might be associated with the clinical outcome as CD4(+) T cells, notably CD4(+) T effector memory cells, were shown to be associated with rejection

Association between cytomegalovirus infection, enhanced proinflammatory response and low level of anti-hemagglutinins during the anti-influenza vaccination--an impact of immunosenescence.

We assessed association between prior cytomegalovirus (CMV) infection, proinflammatory status and effectiveness of the anti-influenza vaccination. We examined 154 individuals during the epidemic season dividing them according to the age, response to the vaccine and the Senieur Protocol (SP). The anti-hemagglutinins (HI), tumour necrosis factor alpha (TNFalpha), interleukin (IL) 1beta, IL6, IL10, ACTH/cortisol axis, anti-CMV antibodies and CD28+CD57- lymphocytes were assessed. Non-responders of both ages we characterised by higher levels of anti-CMV IgG and higher percentages of CD57+CD28- lymphocytes (known to be associated with CMV carrier status) together with increased concentrations of TNFalpha and IL6 and decreased levels of cortisol. The anti-influenza vaccine induced increase in TNFalpha and IL10 in the all non-responders, while cortisol increased only in the young. Concluding, CMV carrier status eliciting elevated proinflammatory potential could contribute to unresponsiveness to the anti-influenza vaccine

Immune consequences of the spontaneous pro-inflammatory status in depressed elderly patients.

INTRODUCTION: The aim of the study was to describe the interrelationship between senescence, depression, and immunity. METHODS: We assessed 10 elderly patients with depression and 10 age- and sex-matched controls: before, at one and at six month intervals after the anti-influenza vaccination. Levels of TNFalpha, IL6, ACTH, and cortisol, titres of anti-hemagglutinins and anti-neuraminidases, lymphocytes secreting IFNgamma, IL2, IL4, and IL10, cytotoxicity of NK and CD3+ CD8+ IFNgamma+ cells, anti-CMV antibodies, and CD28- CD57+ lymphocytes known to be associated with the CMV carrier status were evaluated. RESULTS: Higher levels of anti-CMV, higher percentage of the CD28- CD57+ cells, and elevated levels of TNFalpha, IL6, and cortisol concomitant with decreased levels of ACTH and insufficient production of IL10 (which increased the IFNgamma+ /IL10+ ratio) were found in the patients suffering from depression, in comparison to healthy controls. The subjects with depression revealed a low NK cytotoxicity, while a level of CD3+ CD8+ IFNgamma+ cells was comparable between the groups. Although the levels of anti-hemagglutinins and anti-neuraminidases were low in the depressed patients, they reached the protective titres. The majority of these differences disappeared when CMV titres were entered into the analyses as a covariate. DISCUSSION: The results suggest that the elderly depressed patients were characterised by increased exposure to CMV in the past, which could have resulted in a pro-inflammatory profile demonstrated as elevated levels of TNFalpha, IL6 and deficiency of suppressive IL10+ cells. These changes negatively affect humoral and innate response in the depressed patients

Immune consequences of the spontaneous pro-inflammatory status in depressed elderly patients.

INTRODUCTION: The aim of the study was to describe the interrelationship between senescence, depression, and immunity. METHODS: We assessed 10 elderly patients with depression and 10 age- and sex-matched controls: before, at one and at six month intervals after the anti-influenza vaccination. Levels of TNFalpha, IL6, ACTH, and cortisol, titres of anti-hemagglutinins and anti-neuraminidases, lymphocytes secreting IFNgamma, IL2, IL4, and IL10, cytotoxicity of NK and CD3+ CD8+ IFNgamma+ cells, anti-CMV antibodies, and CD28- CD57+ lymphocytes known to be associated with the CMV carrier status were evaluated. RESULTS: Higher levels of anti-CMV, higher percentage of the CD28- CD57+ cells, and elevated levels of TNFalpha, IL6, and cortisol concomitant with decreased levels of ACTH and insufficient production of IL10 (which increased the IFNgamma+ /IL10+ ratio) were found in the patients suffering from depression, in comparison to healthy controls. The subjects with depression revealed a low NK cytotoxicity, while a level of CD3+ CD8+ IFNgamma+ cells was comparable between the groups. Although the levels of anti-hemagglutinins and anti-neuraminidases were low in the depressed patients, they reached the protective titres. The majority of these differences disappeared when CMV titres were entered into the analyses as a covariate. DISCUSSION: The results suggest that the elderly depressed patients were characterised by increased exposure to CMV in the past, which could have resulted in a pro-inflammatory profile demonstrated as elevated levels of TNFalpha, IL6 and deficiency of suppressive IL10+ cells. These changes negatively affect humoral and innate response in the depressed patients