32 research outputs found

    Surface Modification of Polypropilene Non-woven Substrates by Padding with Antistatic Agents for Deposition of Polyvinyl Alcohol (PVA) Nanofiber Webs by Electrospinning

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    In recent years, the electrospinning process has become one of the most interesting processes to obtain nanofiber webs with interesting properties for uses in a wide variety of industrial sectors such as filtration, chemical barriers, medical devices, etc., as a consequence of the relatively high surface-to-volume ratio. Among the wide variety of polymers, polyvinyl alcohol (PVA) offers good advantages since it is water-soluble and this fact enables easy processing by electrospinning. There are many variables and parameters to be considered in order to optimize PVA nanofiber webs: some of them are related to the polymer solution, some others are related to the process, and some of them are related to the collector substrate. In this work a study on the effects of two different surface pre-treatments on a nonwoven polypropylene substrate as a collector of PVA nanofiber webs has been carried out. In particular, a chemical treatment with anionic antistatics and a physical treatment with lowpressure plasma have been investigated. The effects of these pre-treatments on morphology of PVA nanofiber webs have been evaluated by scanning electron microscopy. Results show that surface resistivity is one of the main parameters influencing the web formation as well as the nature of the electric charge achieved by the pre-treatment. The plasma treatment promotes changes in surface resistivity but it is not enough for good web deposition. Chemical pre-treatment (padding) with anionic antistatic leads to a decrease in surface resistivity up to values in the 1 × 109– 1 × 1011 Ω which is enough for good nanofiber deposition.This work was supported by the Ministerio de Ciencia y Tecnologia, grant number DPI2007-66849-C02-02.Blanes, M.; Marco, B.; Gisbert, MJ.; Bonet Aracil, MA.; Balart Gimeno, RA. (2010). Surface Modification of Polypropilene Non-woven Substrates by Padding with Antistatic Agents for Deposition of Polyvinyl Alcohol (PVA) Nanofiber Webs by Electrospinning. Textile Research Journal. 80(13):1335-1346. https://doi.org/10.1177/0040517509358801S133513468013Burger, C., Hsiao, B. S., & Chu, B. (2006). NANOFIBROUS MATERIALS AND THEIR APPLICATIONS. Annual Review of Materials Research, 36(1), 333-368. doi:10.1146/annurev.matsci.36.011205.123537Dersch, R., Steinhart, M., Boudriot, U., Greiner, A., & Wendorff, J. H. (2005). Nanoprocessing of polymers: applications in medicine, sensors, catalysis, photonics. Polymers for Advanced Technologies, 16(2-3), 276-282. doi:10.1002/pat.568Frenot, A., & Chronakis, I. S. (2003). Polymer nanofibers assembled by electrospinning. Current Opinion in Colloid & Interface Science, 8(1), 64-75. doi:10.1016/s1359-0294(03)00004-9GOPAL, R., KAUR, S., MA, Z., CHAN, C., RAMAKRISHNA, S., & MATSUURA, T. (2006). Electrospun nanofibrous filtration membrane. Journal of Membrane Science, 281(1-2), 581-586. doi:10.1016/j.memsci.2006.04.026Qin, X.-H., & Wang, S.-Y. (2006). Filtration properties of electrospinning nanofibers. Journal of Applied Polymer Science, 102(2), 1285-1290. doi:10.1002/app.24361Ren, G., Xu, X., Liu, Q., Cheng, J., Yuan, X., Wu, L., & Wan, Y. (2006). Electrospun poly(vinyl alcohol)/glucose oxidase biocomposite membranes for biosensor applications. Reactive and Functional Polymers, 66(12), 1559-1564. doi:10.1016/j.reactfunctpolym.2006.05.005Lee, S., & Obendorf, S. K. (2007). Use of Electrospun Nanofiber Web for Protective Textile Materials as Barriers to Liquid Penetration. Textile Research Journal, 77(9), 696-702. doi:10.1177/0040517507080284Heikkilä, P., Sipilä, A., Peltola, M., Harlin, A., & Taipale, A. (2007). Electrospun PA-66 Coating on Textile Surfaces. Textile Research Journal, 77(11), 864-870. doi:10.1177/0040517507078241Boudriot, U., Dersch, R., Greiner, A., & Wendorff, J. H. (2006). Electrospinning Approaches Toward Scaffold Engineering?A Brief Overview. Artificial Organs, 30(10), 785-792. doi:10.1111/j.1525-1594.2006.00301.xButtafoco, L., Kolkman, N. G., Engbers-Buijtenhuijs, P., Poot, A. A., Dijkstra, P. J., Vermes, I., & Feijen, J. (2006). Electrospinning of collagen and elastin for tissue engineering applications. Biomaterials, 27(5), 724-734. doi:10.1016/j.biomaterials.2005.06.024Lee, L. J. (2006). Polymer Nanoengineering for Biomedical Applications. Annals of Biomedical Engineering, 34(1), 75-88. doi:10.1007/s10439-005-9011-6Chew, S. Y., Hufnagel, T. C., Lim, C. T., & Leong, K. W. (2006). Mechanical properties of single electrospun drug-encapsulated nanofibres. Nanotechnology, 17(15), 3880-3891. doi:10.1088/0957-4484/17/15/045Huang, Z.-M., He, C.-L., Yang, A., Zhang, Y., Han, X.-J., Yin, J., & Wu, Q. (2006). Encapsulating drugs in biodegradable ultrafine fibers through co-axial electrospinning. Journal of Biomedical Materials Research Part A, 77A(1), 169-179. doi:10.1002/jbm.a.30564Kim, H.-W., Lee, H.-H., & Knowles, J. C. (2006). Electrospinning biomedical nanocomposite fibers of hydroxyapatite/poly(lactic acid) for bone regeneration. Journal of Biomedical Materials Research Part A, 79A(3), 643-649. doi:10.1002/jbm.a.30866Taepaiboon, P., Rungsardthong, U., & Supaphol, P. (2006). Drug-loaded electrospun mats of poly(vinyl alcohol) fibres and their release characteristics of four model drugs. Nanotechnology, 17(9), 2317-2329. doi:10.1088/0957-4484/17/9/041Ding, B., Kim, H.-Y., Lee, S.-C., Shao, C.-L., Lee, D.-R., Park, S.-J., … Choi, K.-J. (2002). Preparation and characterization of a nanoscale poly(vinyl alcohol) fiber aggregate produced by an electrospinning method. Journal of Polymer Science Part B: Polymer Physics, 40(13), 1261-1268. doi:10.1002/polb.10191Cui, W., Li, X., Zhou, S., & Weng, J. (2006). Investigation on process parameters of electrospinning system through orthogonal experimental design. Journal of Applied Polymer Science, 103(5), 3105-3112. doi:10.1002/app.25464Deitzel, J. ., Kleinmeyer, J., Harris, D., & Beck Tan, N. . (2001). The effect of processing variables on the morphology of electrospun nanofibers and textiles. Polymer, 42(1), 261-272. doi:10.1016/s0032-3861(00)00250-0Lyons, J., Li, C., & Ko, F. (2004). Melt-electrospinning part I: processing parameters and geometric properties. Polymer, 45(22), 7597-7603. doi:10.1016/j.polymer.2004.08.071Theron, S. A., Zussman, E., & Yarin, A. L. (2004). Experimental investigation of the governing parameters in the electrospinning of polymer solutions. Polymer, 45(6), 2017-2030. doi:10.1016/j.polymer.2004.01.024Kilic, A., Oruc, F., & Demir, A. (2008). Effects of Polarity on Electrospinning Process. Textile Research Journal, 78(6), 532-539. doi:10.1177/0040517507081296Reneker, D. H., & Chun, I. (1996). Nanometre diameter fibres of polymer, produced by electrospinning. Nanotechnology, 7(3), 216-223. doi:10.1088/0957-4484/7/3/009Lee, J. S., Choi, K. H., Ghim, H. D., Kim, S. S., Chun, D. H., Kim, H. Y., & Lyoo, W. S. (2004). Role of molecular weight of atactic poly(vinyl alcohol) (PVA) in the structure and properties of PVA nanofabric prepared by electrospinning. Journal of Applied Polymer Science, 93(4), 1638-1646. doi:10.1002/app.20602Mit-uppatham, C., Nithitanakul, M., & Supaphol, P. (2004). Effects of Solution Concentration, Emitting Electrode Polarity, Solvent Type, and Salt Addition on Electrospun Polyamide-6 Fibers: A Preliminary Report. Macromolecular Symposia, 216(1), 293-300. doi:10.1002/masy.200451227Kim, S. J., Lee, C. K., & Kim, S. I. (2005). Effect of ionic salts on the processing of poly(2-acrylamido-2-methyl-1-propane sulfonic acid) nanofibers. Journal of Applied Polymer Science, 96(4), 1388-1393. doi:10.1002/app.21567ZHANG, C., YUAN, X., WU, L., & SHENG, J. (2006). PROPERTIES OF ULTRAFINE FIBROUS POLY(VINYL ALCOHOL) MEMBRANES BY ELECTROSPINNING. Acta Polymerica Sinica, 006(2), 294-297. doi:10.3724/sp.j.1105.2006.00294Supaphol, P., & Chuangchote, S. (2008). On the electrospinning of poly(vinyl alcohol) nanofiber mats: A revisit. Journal of Applied Polymer Science, 108(2), 969-978. doi:10.1002/app.27664Jones, R. N. (1962). THE EFFECTS OF CHAIN LENGTH ON THE INFRARED SPECTRA OF FATTY ACIDS AND METHYL ESTERS. Canadian Journal of Chemistry, 40(2), 321-333. doi:10.1139/v62-050Yao, L., Haas, T. W., Guiseppi-Elie, A., Bowlin, G. L., Simpson, D. G., & Wnek, G. E. (2003). Electrospinning and Stabilization of Fully Hydrolyzed Poly(Vinyl Alcohol) Fibers. Chemistry of Materials, 15(9), 1860-1864. doi:10.1021/cm0210795Wei, Q. F., Gao, W. D., Hou, D. Y., & Wang, X. Q. (2005). Surface modification of polymer nanofibres by plasma treatment. Applied Surface Science, 245(1-4), 16-20. doi:10.1016/j.apsusc.2004.10.013Garcia, D., Sanchez, L., Fenollar, O., Lopez, R., & Balart, R. (2008). Modification of polypropylene surface by CH4–O2 low-pressure plasma to improve wettability. Journal of Materials Science, 43(10), 3466-3473. doi:10.1007/s10853-007-2322-2López, R., Sanchis, R., García, D., Fenollar, O., & Balart, R. (2009). Surface characterization of hydrophilic coating obtained by low-pressure CH4O2plasma treatment on a polypropylene film. Journal of Applied Polymer Science, 111(6), 2992-2997. doi:10.1002/app.29324Tsai, P. P., Schreuder-Gibson, H., & Gibson, P. (2002). Different electrostatic methods for making electret filters. Journal of Electrostatics, 54(3-4), 333-341. doi:10.1016/s0304-3886(01)00160-

    Influence of glyoxal in the physical characterization of PVA nanofibres

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    [EN] The influence of solution composition is directly related to the properties of polyvinyl alcohol (PVA) nanofibers. Electrospinning is a viable technique to develop PVA nanofibers. The presence of a crosslinking agent such as glyoxal can produce variations not only in anti-water solubility effect, but also in the morphology of the electrodeposited fibers. The objective of this study was to characterize the influence of glyoxal on PVA nanofibers. Thus, we studied fiber dimensions, the weight of deposited fibers, and fiber crystallinity. The relation between those properties and the properties of the nanofiber web (color, opacity, and roughness) were studied. In this study we changed glyoxal concentration. Scanning electron microscopy, differential scanning calorimetry, and atomic force microscopy showed changes in the fiber properties. We could observe how the diameter fiber increased, the collector surface was widely covered, and the fiber crystallinity decreased. Regarding the properties of the web, the roughness decreased and the color turned whiter.The authors wish to acknowledge the financial support of the MINISTERIO DE CIENCIA E INNOVACION. Ref: CIT-020000-2008-016 for financial support. Also, the microscopy services at UPV are gratefully acknowledged for their assistance in using AFM techniques, and Octavio Fenollar at UPV is gratefully acknowledged for his assistance in using calorimetric techniques.Blanes, M.; Gisbert, MJ.; Marco, B.; Bonet Aracil, MA.; Gisbert Paya, J.; Balart Gimeno, RA. (2010). Influence of glyoxal in the physical characterization of PVA nanofibres. Textile Research Journal. 80(14):1465-1472. doi:10.1177/0040517509357654S14651472801

    Prediction of ventricular arrhythmia in phospholamban p.Arg14del mutation carriers-reaching the frontiers of individual risk prediction

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    AIMS: This study aims to improve risk stratification for primary prevention implantable cardioverter defibrillator (ICD) implantation by developing a new mutation-specific prediction model for malignant ventricular arrhythmia (VA) in phospholamban (PLN) p.Arg14del mutation carriers. The proposed model is compared to an existing PLN risk model. METHODS AND RESULTS: Data were collected from PLN p.Arg14del mutation carriers with no history of malignant VA at baseline, identified between 2009 and 2020. Malignant VA was defined as sustained VA, appropriate ICD intervention, or (aborted) sudden cardiac death. A prediction model was developed using Cox regression. The study cohort consisted of 679 PLN p.Arg14del mutation carriers, with a minority of index patients (17%) and male sex (43%), and a median age of 42 years [interquartile range (IQR) 27–55]. During a median follow-up of 4.3 years (IQR 1.7–7.4), 72 (10.6%) carriers experienced malignant VA. Significant predictors were left ventricular ejection fraction, premature ventricular contraction count/24 h, amount of negative T waves, and presence of low-voltage electrocardiogram. The multivariable model had an excellent discriminative ability {C-statistic 0.83 [95% confidence interval (CI) 0.78–0.88]}. Applying the existing PLN risk model to the complete cohort yielded a C-statistic of 0.68 (95% CI 0.61–0.75). CONCLUSION: This new mutation-specific prediction model for individual VA risk in PLN p.Arg14del mutation carriers is superior to the existing PLN risk model, suggesting that risk prediction using mutation-specific phenotypic features can improve accuracy compared to a more generic approach

    A Primary Prevention Clinical Risk Score Model for Patients With Brugada Syndrome (BRUGADA-RISK)

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    OBJECTIVES: The goal of this study was to develop a risk score model for patients with Brugada syndrome (BrS). BACKGROUND: Risk stratification in BrS is a significant challenge due to the low event rates and conflicting evidence. METHODS: A multicenter international cohort of patients with BrS and no previous cardiac arrest was used to evaluate the role of 16 proposed clinical or electrocardiogram (ECG) markers in predicting ventricular arrhythmias (VAs)/sudden cardiac death (SCD) during follow-up. Predictive markers were incorporated into a risk score model, and this model was validated by using out-of-sample cross-validation. RESULTS: A total of 1,110 patients with BrS from 16 centers in 8 countries were included (mean age 51.8 ± 13.6 years; 71.8% male). Median follow-up was 5.33 years; 114 patients had VA/SCD (10.3%) with an annual event rate of 1.5%. Of the 16 proposed risk factors, probable arrhythmia-related syncope (hazard ratio [HR]: 3.71; p < 0.001), spontaneous type 1 ECG (HR: 3.80; p < 0.001), early repolarization (HR: 3.42; p < 0.001), and a type 1 Brugada ECG pattern in peripheral leads (HR: 2.33; p < 0.001) were associated with a higher risk of VA/SCD. A risk score model incorporating these factors revealed a sensitivity of 71.2% (95% confidence interval: 61.5% to 84.6%) and a specificity of 80.2% (95% confidence interval: 75.7% to 82.3%) in predicting VA/SCD at 5 years. Calibration plots showed a mean prediction error of 1.2%. The model was effectively validated by using out-of-sample cross-validation according to country. CONCLUSIONS: This multicenter study identified 4 risk factors for VA/SCD in a primary prevention BrS population. A risk score model was generated to quantify risk of VA/SCD in BrS and inform implantable cardioverter-defibrillator prescription

    Natural History of MYH7-Related Dilated Cardiomyopathy

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    BACKGROUND: Variants in myosin heavy chain 7 (MYH7) are responsible for disease in 1% to 5% of patients with dilated cardiomyopathy (DCM); however, the clinical characteristics and natural history of MYH7-related DCM are poorly described. OBJECTIVE: We sought to determine the phenotype and prognosis of MYH7-related DCM. We also evaluated the influence of variant location on phenotypic expression. METHODS: We studied clinical data from 147 individuals with DCM-causing MYH7 variants (47.6% female; 35.6 ± 19.2 years) recruited from 29 international centers. RESULTS: At initial evaluation, 106 (72.1%) patients had DCM (left ventricular ejection fraction: 34.5% ± 11.7%). Median follow-up was 4.5 years (IQR: 1.7-8.0 years), and 23.7% of carriers who were initially phenotype-negative developed DCM. Phenotypic expression by 40 and 60 years was 46% and 88%, respectively, with 18 patients (16%) first diagnosed at <18 years of age. Thirty-six percent of patients with DCM met imaging criteria for LV noncompaction. During follow-up, 28% showed left ventricular reverse remodeling. Incidence of adverse cardiac events among patients with DCM at 5 years was 11.6%, with 5 (4.6%) deaths caused by end-stage heart failure (ESHF) and 5 patients (4.6%) requiring heart transplantation. The major ventricular arrhythmia rate was low (1.0% and 2.1% at 5 years in patients with DCM and in those with LVEF of ≤35%, respectively). ESHF and major ventricular arrhythmia were significantly lower compared with LMNA-related DCM and similar to DCM caused by TTN truncating variants. CONCLUSIONS: MYH7-related DCM is characterized by early age of onset, high phenotypic expression, low left ventricular reverse remodeling, and frequent progression to ESHF. Heart failure complications predominate over ventricular arrhythmias, which are rare

    Epidemiological trends of HIV/HCV coinfection in Spain, 2015-2019

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    Altres ajuts: Spanish AIDS Research Network; European Funding for Regional Development (FEDER).Objectives: We assessed the prevalence of anti-hepatitis C virus (HCV) antibodies and active HCV infection (HCV-RNA-positive) in people living with HIV (PLWH) in Spain in 2019 and compared the results with those of four similar studies performed during 2015-2018. Methods: The study was performed in 41 centres. Sample size was estimated for an accuracy of 1%. Patients were selected by random sampling with proportional allocation. Results: The reference population comprised 41 973 PLWH, and the sample size was 1325. HCV serostatus was known in 1316 PLWH (99.3%), of whom 376 (28.6%) were HCV antibody (Ab)-positive (78.7% were prior injection drug users); 29 were HCV-RNA-positive (2.2%). Of the 29 HCV-RNA-positive PLWH, infection was chronic in 24, it was acute/recent in one, and it was of unknown duration in four. Cirrhosis was present in 71 (5.4%) PLWH overall, three (10.3%) HCV-RNA-positive patients and 68 (23.4%) of those who cleared HCV after anti-HCV therapy (p = 0.04). The prevalence of anti-HCV antibodies decreased steadily from 37.7% in 2015 to 28.6% in 2019 (p < 0.001); the prevalence of active HCV infection decreased from 22.1% in 2015 to 2.2% in 2019 (p < 0.001). Uptake of anti-HCV treatment increased from 53.9% in 2015 to 95.0% in 2019 (p < 0.001). Conclusions: In Spain, the prevalence of active HCV infection among PLWH at the end of 2019 was 2.2%, i.e. 90.0% lower than in 2015. Increased exposure to DAAs was probably the main reason for this sharp reduction. Despite the high coverage of treatment with direct-acting antiviral agents, HCV-related cirrhosis remains significant in this population

    A Primary Prevention Clinical Risk Score Model for Patients With Brugada Syndrome (BRUGADA-RISK).

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    OBJECTIVES: The goal of this study was to develop a risk score model for patients with Brugada syndrome (BrS). BACKGROUND: Risk stratification in BrS is a significant challenge due to the low event rates and conflicting evidence. METHODS: A multicenter international cohort of patients with BrS and no previous cardiac arrest was used to evaluate the role of 16 proposed clinical or electrocardiogram (ECG) markers in predicting ventricular arrhythmias (VAs)/sudden cardiac death (SCD) during follow-up. Predictive markers were incorporated into a risk score model, and this model was validated by using out-of-sample cross-validation. RESULTS: A total of 1,110 patients with BrS from 16 centers in 8 countries were included (mean age 51.8 ± 13.6 years; 71.8% male). Median follow-up was 5.33 years; 114 patients had VA/SCD (10.3%) with an annual event rate of 1.5%. Of the 16 proposed risk factors, probable arrhythmia-related syncope (hazard ratio [HR]: 3.71; p < 0.001), spontaneous type 1 ECG (HR: 3.80; p < 0.001), early repolarization (HR: 3.42; p < 0.001), and a type 1 Brugada ECG pattern in peripheral leads (HR: 2.33; p < 0.001) were associated with a higher risk of VA/SCD. A risk score model incorporating these factors revealed a sensitivity of 71.2% (95% confidence interval: 61.5% to 84.6%) and a specificity of 80.2% (95% confidence interval: 75.7% to 82.3%) in predicting VA/SCD at 5 years. Calibration plots showed a mean prediction error of 1.2%. The model was effectively validated by using out-of-sample cross-validation according to country. CONCLUSIONS: This multicenter study identified 4 risk factors for VA/SCD in a primary prevention BrS population. A risk score model was generated to quantify risk of VA/SCD in BrS and inform implantable cardioverter-defibrillator prescription

    Estratificación del riesgo en la muerte súbita por miocardiopatía hipertrófica

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    Risk stratification in sudden death due to hypertrophic cardiomyopathyEn los últimos dos años se han publicado trabajos importantes sobre la miocardiopatía hipertrófica (MCH). Desde el punto de vista clínico quizás el más relevante ha sido la publicación de las Guías de Diagnóstico y Tratamiento de la MCH de la European Society of Cardiology (ESC). En este documento uno de los aspectos más novedosos ha sido la presentación de un nuevo índice de riesgo de muerte súbita..

    Sex-related differences in cardiomyopathies

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    Cardiomyopathies (CMPs) are a heterogeneous group of heart muscle diseases with several different phenotypes defined as myocardial disorders in which the heart muscle is structurally and functionally abnormal in the absence of coronary artery disease, hypertension, valvular heart disease and congenital heart disease sufficient to explain the observed myocardial abnormality. CMPs can be classified into one of the following, i.e. hypertrophic CMP (HCM), dilated CMP (DCM), arrhythmogenic right ventricular CMP (ARVC), restrictive CMP (RCM), and unclassified CMPs. Although an increasing number of CMPs are now recognized to have a genetic basis, single mutations are associated with phenotypic variability and may cause not only a specific CMP, but also several different CMPs. Recently, it has become evident that, along with environmental interactions, age and sex may affect the penetrance of disease genes thus determining the phenotypic expression of CMPs. Noteworthy, an increasing body of data indicates that sex plays an important role in various forms of CMPs. The mode of inheritance may affect the sex-related occurrence of CMPs. Also, sex is a relevant determinant of the clinical manifestation of CMPs, and sex-related characteristics can be found in all forms. Sex-specific aspects of clinical disease expression as well as potential modes of inheritance should be therefore taken into proper consideration in order to improve the diagnostic work-up and treatment strategy of CMPs in both sexes
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