Tag: pubmed

Polymers (Basel). 2022 Apr 27;14(9):1793. doi: 10.3390/polym14091793.

ABSTRACT

This work evaluated the fracture toughness of the low-temperature carbonized elastomer-based composites filled with shungite and short carbon fibers. The effects of the carbonization temperature and filler content on the critical stress intensity factor (K_1c) were examined. The K_1c parameter was obtained using three-point bending tests for specimens with different l/b ratio (notch depth to sample thickness) ranging from 0.2 to 0.4. Reliable detection of the initiation and propagation of cracks was achieved using an acoustic sensor was attached to the samples during the bending test. The critical stress intensity factor was found to decrease linearly with increasing carbonization temperature. As the temperature increased from 280 to 380 °C, the K_1c parameter was drastically reduced from about 5 to 1 MPa·m^1/2 and was associated with intense outgassing during the carbonization step that resulted in sample porosity. The carbon fiber addition led to some incremental toughening; however, it reduced the statistical dispersion of the K_1c values.

PMID:35566962 | DOI:10.3390/polym14091793

Polymers (Basel). 2022 Apr 27;14(9):1778. doi: 10.3390/polym14091778.

ABSTRACT

The aim of this in vitro study was to evaluate the effects of substrate and cement shades on the translucency and color of lithium-disilicate and zirconia CAD/CAM materials. Two light-cured resin cements (RelyX Veneer Cement; 3M; Choice 2 Veneer Cement; Bisco Dental) with a standardized thickness (0.1 mm) were tested in combination with two different monolithic CAD/CAM materials (E-Max CAD (LI₂SI₂O₅); Ivoclar Vivadent; Katana (ZrO₂); Kuraray-Noritake Dental) on two different colored composite substrates used as a dentin (Filtek Supreme XTE; 3M); for a total of 12 combinations (n = 10). The specimens’ color was measured with a spectrophotometer (Spectroshade; MHT). Measurements were taken using the CIELAB color coordinate system (L*a*b*) against black and white backgrounds. L*a*b* values were statistically analyzed for the variables Substrate, Ceramic, and Cement by applying a Three-Way ANOVA followed by the Tukey Test for post-hoc comparison (p < 0.05). Translucency Parameter (TP) and Constant Ratio (CR) were assessed to evaluate translucency; acceptability and perceptibility thresholds (ΔE₀₀ 1.8 and 0.8) were used. Statistically significant influence was found for factors ceramic material, cement shade, and substrate color (p < 0.05). Unacceptable color differences were reported for Li₂Si₂O₅. Opacity was significantly higher when white opaque cement shade was employed. Ceramic type and cement shade significantly influenced L*a*b* color coordinates. The final translucency and color of ceramic restorations can, therefore, be influenced by ceramic material, cement shade, and substrate color.

PMID:35566944 | DOI:10.3390/polym14091778

Polymers (Basel). 2022 Apr 26;14(9):1749. doi: 10.3390/polym14091749.

ABSTRACT

(1) Introduction: Denture adhesives (DAs) promote stability, chewing ability, and quality of life. The objective of this study was to compare the effectiveness of original brand DAs and white brands in their retention of conventional complete dentures. (2) Methods: This study followed the recommendations of the international standard ISO 10873. Three original brands of DA (Corega^® Fixação 3D, GlaxoSmithKline^®, Stafford Miller Ltd., Dungarvan Co. Waterford, Ireland), KuKident^® Pro Procter & Gamble Technical Centres^®, Ltd., Whitehal Lane, Germany and Elgydium^® Fix, Laboratórios URGO^® SL, Florida, Spain) were compared to three white brands (Fixação Extra Forte Pingo Doce^®, Laboratórios Cosmodent^®, Cantabria, Spain), Fixador de Próteses (Continente^®, Propack^®,Gmbh, Ladenburg, Germany) and Creme Fixador de Próteses (Auchan^®, Ellipse^®, Roubaix, France). Their retention capacities were analyzed using a mechanical test device. (3) Results: The mean retentive ability of original brand adhesives (M = 11.16, SD = 5.27) was significantly higher (t(298) = 11.88; p < 0.001) than that of the white brands (M = 5.92, SD = 1.18). When comparing all brands, statistically significant differences were also observed, F(5.294) = 707.68 (p < 0.001). The generic adhesive results were more homogeneous. The generic brands from Continente^® (M = 5.24, SD = 0.94) and Auchan^® (M = 5.80, SD = 0.79) were not significantly different, while the Pingo Doce^® brand obtained significantly higher mean retention results (M = 6.71, SD = 1.28). (4) Conclusions: The original brands of DA have a significantly higher retentive ability than the white brands. Elygidim^® Fix had the worst result of the three original brands, and the product from Pingo Doce^® had the best result among the three white brands.

PMID:35566919 | DOI:10.3390/polym14091749

Polymers (Basel). 2022 Apr 19;14(9):1648. doi: 10.3390/polym14091648.

ABSTRACT

Particleboards are used in the manufacturing of furniture and are often part of the interior of buildings. In the event of a fire, particleboards are a substantial part of the fuel in many building fires. The aim of the article is to monitor the effect of radiant heat on the surface of particle board according to the modified procedure ISO 5657: 1997. The significance of the influence of heat flux density and particle board properties on its thermal resistance (time to ignition) was monitored. Experimental samples were used particle board without surface treatment, with thicknesses of 12, 15, and 18 mm. The samples were exposed to a heat flux from 40 to 50 kW·m^-2. The experimental results are the initiation characteristics such as of the ignition temperature and the weight loss. The determined factors influencing the time to ignition and weight loss were the thickness and density of the plate material, the density of the radiant heat flux and the distance of the particle board from the radiant source (20, 40, and 60 mm). The obtained results show a significant dependence of the time to ignition on the thickness of the sample and on the heat flux density. The weight loss is significantly dependent on the thickness of the particle board. Monitoring the influence of time to ignition from sample distance confirmed a statistically significant dependence. As the distance of the sample from the source increased, the time to ignition decreased linearly. As the distance of the sample from the source increased, the time to ignition increased.

PMID:35566818 | DOI:10.3390/polym14091648

Polymers (Basel). 2022 Apr 22;14(9):1715. doi: 10.3390/polym14091715.

ABSTRACT

Currently, the provisional stenting technique is the gold standard in revascularization of lesions located in the left main (LM) bifurcation. The benefit of the routine kissing balloon technique (KBI) in bifurcation lesions is still debated, particularly following the single stent treatment. We compared the latest-generation drug-eluting stent (DES) with no side branch (SB) dilatation “keep it open” technique (KIO) vs. KBI technique vs. bifurcation dedicated drug-eluting stent (BD-DES) implantation. In vitro testing was performed under a static condition in bifurcation silicone vessel models. All the devices were implanted in accordance with the manufacturers’ recommendations. As a result, computational fluid dynamics (CFD) analysis demonstrated a statistically higher area of high shear rate in the KIO group when compared to KBI. Likewise, the maximal shear rate was higher in number in the KIO group. Floating strut count based on the OCT imaging was significantly higher in KIO than in KBI and BD-DES. Furthermore, according to OTC analysis, the thrombus area was numerically higher in both KIO and KBI than in the BD-DES. Scanning electron microscopy (SEM) analysis shows the highest degree of strut coating damage in the KBI group. This model demonstrated significant differences in CFD analysis at SB ostia with and without KBI optimization in the LM setting. The adoption of KBI was related to a meaningful reduction of flow disturbances in conventional DES and achieved results similar to BD-DES.

PMID:35566886 | DOI:10.3390/polym14091715

J Clin Med. 2022 May 9;11(9):2675. doi: 10.3390/jcm11092675.

ABSTRACT

Background: The present study aims to compare the accuracy of jaw repositioning in bimaxillary orthognathic surgery using digital surgical planning in cleft lip and palate patients and in non-syndromic skeletal class III patients in order to investigate if orthognathic surgery achieves different results in the first group of patients. Method: This study included 32 class III adult patients divided into 2 groups: cleft lip and palate (A, n = 16) and non-cleft (B, n = 16). For each patient, a 2D pre-surgical visual treatment objective was performed by the surgeon to predict hard tissue changes, and the surgical outcome was compared with that planned by using cephalometric measurement (ANB, SNA, SNB, Ar-Go-Me, S-Ar-Go). The statistical analysis showed equivalence between obtained and planned results for each measurement both in group A and in group B, but the difference between the planned and the obtained result was smaller in group B regarding ANB angle. Conclusions: Digital surgical planning ensures better predictability of the surgical results and higher accuracy of surgery in complex patients, such as those with cleft lip and palate.

PMID:35566801 | DOI:10.3390/jcm11092675

FASEB J. 2022 May;36 Suppl 1. doi: 10.1096/fasebj.2022.36.S1.L7857.

ABSTRACT

Many medical treatments have been proposed and utilized to mitigate the effects of oxidants on mammalian cells. Some studies have demonstrated the antioxidative effects of EGCG (an active ingredient in green tea) against cellular oxidants such as camptothecin (CAMPT). However, not many studies have shown how EGCG mitigates the effects of CAMPT on UMR cells. We hypothesized that EGCG mitigates the effects of CAMPT on cell proliferation and biophysical parameters in UMR cells by inhibiting CAMPT-induced apoptosis. Briefly, UMR cells were routinely passaged, counted, plated at 4.8 x 10⁵ cells/mL in six-well culture plates, then treated with varying concentrations of CAMPT. The cultures were incubated for 72 hours at 37°C + 5% CO₂ infusion. Cells were subsequently counted to establish the proliferation and viability of the induced cells as compared to controls. In another experiment, designated UMR cells were co-treated with CAMPT and different concentrations of EGCG then processed, as mentioned above, to evaluate whether or not the EGCG treatment was able to mitigate the oxidative effect of CAMPT through proliferation / viability studies. Apoptosis markers were assessed for each experiment by using a Caspase-3/CPP32 Colorimetric Assay Kit. Lastly, designated cells were treated with CAMPT alone, or CAMPT +EGCG then assessed using electric cell-substrate impedance sensing (ECIS) technology to explore the effects of the chemicals used on key biophysical parameters of UMR cells (i.e. cell membrane resistance, rate of cell spreading and cell attachment). Briefly, CAMPT-treated and CAMPT+EGCG-treated UMR cells were plated at 2.5 x 10⁵ cells/mL in eight-well ECIS array plates. The plates were placed into the ECIS array holder and incubated at 37°C with 5% CO₂. The biophysical parameters (cell membrane resistance/impedance, cell spreading, cell attachment) were monitored and measured in real-time for 48 hours, using the ECIS instrument. F test ANOVA was used to compare variances between all trials and all values in the results were expressed as means ±SD. The results of the proliferation study showed a decrease in CAMPT-treated UMR cell proliferation in a concentration-dependent manner (Figure 1). Cells co-treated with CAMPT + EGCG revealed that EGCG was able to reverse the oxidative effects of CAMPT on the UMR cells in a concentration-dependent manner *Figure 2). The Caspase-3/CPP32 Colorimetric Assay showed an increase in apoptotic marker activity from the CAMPT-induced samples in contrast with the uninduced controls. The ECIS technology documented decreases in biophysical parameters in the UMR cells when CAMPT alone was used. Co-treatment of the cells with CAMPT+EGCG showed a reverse effect on the biophysical parameters. F-Test ANOVA yielded statistically significant values with p values <0.05. The results of this research suggest that EGCG is effective in protecting UMR cells from oxidative stress by inhibiting apoptosis. Moreover, results from the ECIS instrument validates this technology as a corroborator of the biological effects of CAMPT and EGCG on UMR cells. This study suggests that EGCG has a protective role in mitigating oxidative stress in mammalian cells.

PMID:35557469 | DOI:10.1096/fasebj.2022.36.S1.L7857

FASEB J. 2022 May;36 Suppl 1. doi: 10.1096/fasebj.2022.36.S1.L7913.

ABSTRACT

Tissue resident macrophages play a major role in the regulation of the extracellular matrix (ECM). The ECM provides an essential scaffold and mechanical stability for blood vessels, but remodeling due to acute injury or chronic inflammatory conditions like hypertension promotes vascular stiffening. We have previously shown that pulse wave velocity (PWV), a measure of arterial stiffness, is higher in male and ovariectomized (OVX) female mice versus intact female mice. RNA-sequencing of aortas from intact and OVX mice revealed changes in several genes involved in fibrosis as well as macrophage function. Therefore, we hypothesized that estrogen protects from arterial stiffening through maintenance of “protective” macrophages and limiting pro-fibrotic ECM components. Based on the RNAseq results, we assessed the impact of estrogen on aortic expression of four fibrosis-associated genes: decorin (DCN), endothelin-1 (Edn1), type III collagen α1 (Col3a1), and connective tissue growth factor (CTGF) as well as four cell surface macrophage markers: colony stimulating factor 1 receptor (CSF1R), lymphatic vessel endothelial hyaluronan receptor 1 (LYVE1), AXL receptor tyrosine kinase (Axl), and growth arrest specific 6 (Gas6).

METHODS: Female C57BL/6 mice were ovariectomized (OVX) at 8 weeks or remained intact. PWV was obtained as a measure of arterial stiffness using a Vevo 1100 high resolution ultrasound. Mice were euthanized between 20-23 weeks of age for tissue collection. RNA was isolated from aortas using a Qiagen RNeasy Mini Kit and gene expression was quantified using droplet digital polymerase chain reaction (ddPCR). Statistical analysis was performed using an unpaired t-test.

RESULTS: Abdominal PWV was increased in OVX mice compared with intact mice (p<0.0001). Surprisingly, OVX induced a significant decrease (p=0.045) in DCN expression, while a downward trend was found for CTGF (p=0.10) and Col3a1 (p=0.08) but not Edn1 (p=0.59). OVX also decreased the expression of macrophage markers CSF1R (p=0.022) and LYVE1 (p=0.047), with a downward trend for Gas6 (p=0.096) but not Axl (0.161).

CONCLUSION: Increased PWV in OVX mice was not accompanied by upregulation of pro-fibrotic genes but was associated with decreases in macrophage markers CSF1R and LYVE1 in the aorta. Therefore, estrogen loss may promote vascular stiffening through changes in the amounts or functions of specific subsets of macrophages in the vasculature. Our data support previous studies establishing a relationship between CSF1R, LYVE1, and arterial homeostasis. Future studies will examine the impact of estrogen on aortic tissue resident macrophages using flow cytometry and the downstream signaling that promotes arterial stiffening.

PMID:35557457 | DOI:10.1096/fasebj.2022.36.S1.L7913

FASEB J. 2022 May;36 Suppl 1. doi: 10.1096/fasebj.2022.36.S1.R2228.

ABSTRACT

Fat embolism induced in rats by intravenous injection of triolein(T) causes pulmonary inflammation, fibrosis, and vasculitis after 48 hours ort 10 weeks. Administration of Aliskiren, Captopril and Losartan drugs, which interfere with the renin angiotensin aldosterone system, ameliorates the pulmonary damage. Macrophages and mast cell number decreased with drugs administration. Hearts do not exhibit inflammation or vasculitis although significant emboli are detected at 48 hours. Pulmonary expression of renin, prorenin(R/P) positive cells are also increased after T injection. This study investigates whether the presence of R/P cells correlates with macrophages and mast cell invasion in the hearts and lungs.

METHODOLOGY: 24 Sprague Dawley rats were divided into four groups and treated with 0.2 ml of T or Saline. Lungs and hearts from 3 animals from each group that were sacrificed 48 hours or 10 weeks, fixed in formalin and stained with Hematoxylin-Eosin, Trichrome or immunostained with antibodies to CD117, CD68 to identify mast cells and macrophages. Sections of the heart and the lung were evaluated at 400X magnification. Cells were counted, histopathology examined and statistical significance evaluated using GraphPad software.

RESULTS: While the lungs showed the previously reported, histopathological damage caused by the inflammation, vasculitis, fibrosis and cell necrosis, the hearts did not show such damage, thus confirming previous observations. Contrary to the lungs where the number of CD117, CD68 and R/P positive cells was significantly increased at both interval times, no difference in CD117, CD68, R/P positive cell numbers were observed in the heart. In the lungs, two distinct types of macrophages were identified, one large and the second one of normal size. Such histopathological changes were not observed in the hearts. Hearts exhibited distinct locations of CD117 and CD68 positive cells, with multiple cells located primarily near the myocardium and few in the adventitia of the coronary arteries, in contrast to lungs where the cells were mostly located around the arteries.

CONCLUSION: The study confirms the previously reported histopathological difference of the T induced damage in the lungs compared to that of the hearts in this model of fat embolization. This finding highlights the variation in cellular response of diverse organs to fat embolism. This difference is not only related to the number of the inflammatory cells but also to their location in different organs as evidenced by the difference in the distribution and location of R/P cells in hearts and lungs. Future studies will investigate the underlying mechanisms that lead to pulmonary susceptibility while preserving cardiac integrity in response to a FE induced inflammatory response in order to better design a therapeutic intervention for the fat embolism syndrome.

PMID:35557437 | DOI:10.1096/fasebj.2022.36.S1.R2228

FASEB J. 2022 May;36 Suppl 1. doi: 10.1096/fasebj.2022.36.S1.L6410.

ABSTRACT

BACKGROUND: Pesticides are important biological agents that deter or kill pests. Globally, about 2 million tons of pesticides are being utilized each year which highlights their importance. Previous studies have suggested that high levels of pesticide exposure are associated with increased risk of chronic diseases, including cancers, cardiotoxicity, Parkinson’s disease, diabetes mellitus, neurological deficits, birth defects, and reproductive disorders. Prometryn is a commonly used selective triazine herbicide, which is currently used as an alternative to atrazine-based products. It is widely applied to agriculture as it has lower acute toxicity than atrazine herbicides, stable chemical properties, and a long period of effectiveness. Although past studies have shown that triazine herbicides have carcinogenic potential in humans, the cytotoxic effects of prometryn on cardiac and hepatic systems are not well investigated or understood. The aim of this study was to determine the effects of prometryn on the heart and liver.

METHODS: H9c2 cardiac and HepG2 liver carcinoma cells were used to study the in-vitro effects of prometryn. Cells were treated with varying concentrations of prometryn for 24 h. Cell viability, mitochondrial membrane potential, and reactive oxygen species (ROS) levels were assessed. For animal studies, male mice (10 weeks old) (n=24) were randomized to two treatment groups (control and prometryn). The control group received corn oil while the prometryn treated group were exposed to 185mg/kg b.w. prometryn dissolved in corn oil every 48 hours for 7 days. After a total of 4 doses, mice were euthanized, and the heart and liver tissues were collected. Proteasome and immunoproteasome activity were measured in the heart and liver. Protein expression levels of markers for oxidative stress, apoptosis, and proteasomal degradation such as GSTT2, GSTA1/2, Hsp70, Hsp27, NADPH oxidase, PARP-1, p53, PSMD12, LMP2, DNP, VU-1 were detected using immunoblotting. Protein oxidation and polyubiquitination were detected as an indicator of oxidative stress. A paired t-test was used to assess group differences for protein levels and p values <0.05 were deemed statistically significant.

RESULT: We found that prometryn had a concentration-dependent effects on H9c2 and HepG2 cell lines when we assessed cell viability, mitochondria function, and total intracellular reactive oxygen species formation. Increasing the concentration of prometryn increased the ROS formation, decreased cell viability and decreased mitochondrial membrane potential in these cell lines. Furthermore, in animal studies we observed changes in the proteasome and immunoproteasome activities in the liver but not in the heart. Changes in protein expression levels of oxidative stress and proteasomal degradation markers were only detected in the liver.

CONCLUSION: These results indicate that H9c2 and HepG2 cells are sensitive to prometryn in-vitro. However, prometryn effects on the heart and liver tissue in male mice is significantly different. Overall, our data supports the deduction that prometryn affected mitochondrial function, induced oxidative stress in cells, but also alters the ubiquitin-proteasome system and increases oxidative stress in mice liver. These results help towards elucidation of the mechanism by which prometryn could cause diseases.

PMID:35557455 | DOI:10.1096/fasebj.2022.36.S1.L6410