Chitosan Nanoparticles Functionalized Viscose Fabrics as Potentially Durable Antibacterial Medical Textiles.

This research proposed two pretreatments of viscose fabrics: oxidation with 2,2,6,6-tetramethylpiperidine-1-oxy radical (TEMPO) and coating with TEMPO-oxidized cellulose nanofibrils (TOCN), to introduce functional groups (COOH and CHO) suitable for irreversible binding of chitosan nanoparticles without and with embedded zinc (NCS and NCS + Zn, respectively) and consequently achieving washing durable antibacterial properties of the chitosan nanoparticles functionalized fabrics. The characterizations of pretreated and chitosan nanoparticles functionalized fabrics were performed by FTIR and XPS spectroscopy, elemental analysis, inductively coupled plasma optical emission spectrometry, zeta potential measurements, scanning electron microscopy, determination of COOH and CHO groups content, and antimicrobial activity under dynamic contact conditions. Influence of pretreatments on NCS and NCS + Zn adsorption, chemical, electrokinetic, and antibacterial properties as well as morphology, and washing durability of NCS and NCS + Zn functionalized fabrics were studied and compared. Washing durability was evaluated through changes in the chitosan and zinc content, zeta potential, and antibacterial activity after 1, 3, and 5 washing cycles. Pretreatments improved washing durability of antibacterial properties of chitosan nanoparticles functionalized fabrics. The NCS and NCS + Zn functionalized pretreated fabrics preserved antibacterial activity against S. aureus after five washing cycles, while antibacterial activity against E. coli was preserved only after one washing cycle in the case NCS + Zn functionalized pretreated viscose fabrics.

Effect of plasma treatment on chemical composition, structure and sorption properties of lignocellulosic hemp fibers (Cannabis sativa L.).

Hemp fibers with different amount of hemicelluloses and lignin were subjected to atmospheric pressure dielectric barrier discharge under different conditions (40 W and 80 W power of discharge, const. time 120 s) in order to study influence of plasma treatment on their structure and sorption properties. Wettability of plasma treated samples, compared with precursors, increased due to the changes in hemp fiber surface chemistry confirmed by ATR FTIR spectroscopy and increased roughness as a consequence of intensive surface etching, observed by SEM. After plasma treatment, wettability was the highest for hemp fibers with lower content of hemicelluloses (increase up to 9 times), while wettability of raw hemp fibers and fibers with lower content of lignin increased about 5 and 2 times, respectively. This investigation shows that plasma can be successfully used for improvement of raw hemp fibers wettability, even to substitute the chemical treatment for some applications of hemp.

Influence of Different Pretreatments on the Antibacterial Properties of Chitosan Functionalized Viscose Fabric: TEMPO Oxidation and Coating with TEMPO Oxidized Cellulose Nanofibrils.

The main objective of this study was to obtain chitosan functionalized viscose fabric with improved antibacterial properties and washing durability. In this regard carboxyl and aldehyde groups, as binding points for irreversible chitosan attachment into/onto viscose fabric, were introduced by two different pretreatments: 2,2,6,6-tetramethylpiperidine-1-oxy radical (TEMPO) oxidation and coating with TEMPO oxidized cellulose nanofibrils (TOCN). The Fourier transform infrared spectroscopy, elemental analysis, zeta potential measurements, scanning electron microscopy, breaking strength and antibacterial testing were used to evaluate the influence of these pretreatments on chitosan binding, but also on chemical, electrokinetic, morphological, mechanical and antibacterial properties of pretreated and chitosan functionalized viscose fabrics. Washing durability of chitosan functionalized viscose was monitored through changes in the chitosan content, electrokinetic and antibacterial properties after multiple washing. TOCN coating improves mechanical properties of fabric, while TEMPO oxidation deteriorates them. The results show that both pretreatments improve chitosan adsorption and thus antibacterial properties, which are highly durable to washing. After five washings, the chitosan functionalized pretreated viscose fabrics preserve their antibacterial activity against Staphylococcus aureus, while antibacterial activity against Escherichia coli was lost. TOCN coated and chitosan functionalized viscose fabric is a high value-added product with simultaneously improved antibacterial and mechanical properties, which may find application as medical textiles.

Factors affecting the patency of arteriovenous fistulas for hemodialysis: Single center experience.

INTRODUCTION: Arteriovenous fistulas (AVFs) are the preferred form vascular access for hemodialysis (HD), as they have a low rate of complications and durable function. The aim of our investigation was to analyze the factors that might influence the function of AVFs. METHODS: Data were taken from the computerized patient record system in the Clinic of Urology and Nephrology, Clinical Center, Kragujevac, Serbia, for a 2-year period. We analyzed patients who had requested re-creation of AVFs as a secondary procedure. During this period 112 patients, 73 (65%) men and 39 (35%) women, had AVF thromboses. All relevant clinical and laboratory parameters that could affect the function and survival of AVF were evaluated. FINDINGS: In univariate logistic regression analysis, statistically significant predictors influencing the duration of the fistula were magnesium (P < 0.001), triglycerides (P = 0.041), smoking (P = 0.001), antiplatelet therapy (P < 0.001), and type of HD (bicarbonate vs. hemodiafiltration) (P < 0.001). In the multiple logistic regression model, high concentrations of magnesium (B = 7.434; P < 0.001) and antiplatelet therapy (B - 1.042; P = 0.04) were significantly associated with the length of AVF function. DISCUSSION: After successful establishment of an AVF, there is a compelling need to maintain fistula patency. Factors that affect functioning of the AVFs are presently under intense scrutiny. According to our results, some clinical factors may determine long term fistula duration, such as concentration of the magnesium and antiplatelet therapy.

Cannulation Technique and Arteriovenous Fistula Survival in Older Adult Patients on Hemodialysis.

Cannulation technique has the potential to impact arteriovenous fistula (AVF) function. The aim of this research was to determine the impact of cannulation technique on the length of the functioning AVFs in older adult patients on hemodialysis. The study included 110 participants with fistula thrombosis who had used area technique or rope ladder technique. Biochemical parameters, gender, demographic, and clinical variables were determined. Patients who used the area cannulation technique differed significantly from patients using the rope ladder technique with regard to duration of hemodialysis (p < 0.001), outcome of the AVF revision (p = 0.045), and positioning of the anastomosis (p = 0.013). The group that used the area cannulation technique had a longer duration of hemodialysis, proximal anastomoses, and more successful revisions of AVFs.

Correlation between nonalcoholic fatty liver and cardiovascular disease in elderly hemodialysis patients.

PURPOSE: The number of elderly patients with end-stage kidney disease is on the rise. Nonalcoholic fatty liver disease (NAFLD) is characterized by parenchymal fat accumulation in patients without information about alcohol abuse. The aim of our study was to determine correlation between NAFLD and cardiovascular diseases in elderly hemodialysis patients. METHODS: The examination was organized as observational and cross-sectional study in elderly patients on hemodialysis. An abdominal ultrasound examination was made in order to define NAFLD. Intima-media thickness of the carotid arteries was quantified by Doppler ultrasound. Biochemical parameters, gender, anthropometric characteristics, duration, adequacy of hemodialysis, blood pressure, smoking and cardiovascular disease were determined. Respondents were divided into a group with NAFLD (37/72 patients, 51 %) and group without NAFLD (35/72 patients, 49 %). RESULTS: Patients with NAFLD have significantly more cardiovascular disease (p = 0.017) as well as significantly higher values of intima-media thickness of the carotid arteries (p = 0.03) in correlation with patients without NAFLD. Patients without NAFLD have a statistically lower triglyceride (p = 0.04), aspartate aminotransferase (p = 0.006), alanine aminotransferase (p = 0.013) and gamma-glutamyl transpeptidase (p = 0.029) compared to patients with NAFLD. Patients with cardiovascular disease have a higher risk of NAFLD; likewise, patients with NAFLD have a three times higher chance for developing cardiovascular diseases (OR 3.01). CONCLUSION: Elderly patients on hemodialysis with cardiovascular disease have a higher risk of NAFLD; likewise, patients with NAFLD have a three times higher chance for developing cardiovascular diseases.

Is low magnesium a clue to arteriovenous fistula complications in hemodialysis?

PURPOSE: Magnesium insufficiency is a pro-atherogenic factor involved in endothelial dysfunction, atherosclerosis, and vascular calcification. Our aim was to examine the role of magnesium in the development of arteriovenous fistula complications in hemodialysis. METHODS: This was a retrospective clinical investigation of data from 88 patients who were divided into two groups: those with and without arteriovenous fistula complications. We examined the influence of sex, demographics, and clinical and laboratory parameters. The existence of fistula stenosis was determined by measuring Doppler flow, while B-mode ultrasound was used to detect plaques and evaluate the carotid artery intima-media thickness. RESULTS: Patients with arteriovenous fistula complications had significantly higher leukocyte counts (p = 0.03), platelet counts (p = 0.03), phosphate concentrations (p = 0.044), and alkaline phosphatase concentrations (p = 0.04). Patients without complications had significantly greater blood flow through the arteriovenous fistula (p < 0.0005), higher magnesium concentrations (p = 0.004), and a lower carotid artery intima-media thickness (p = 0.037). The magnesium level was inversely correlated with leukocyte (p = 0.028) and platelet (p = 0.016) counts. The magnesium concentration was significantly lower in patients with carotid artery plaques (p = 0.03). Multiple linear regression, using magnesium as the dependent variable in patients with arteriovenous fistula complications, indicated statistically significant correlations with platelet (p = 0.005) and leukocyte (p = 0.027) counts and carotid plaques (p = 0.045). CONCLUSIONS: Hypomagnesemia is a significant pro-atherogenic factor and an important predictor of arteriovenous fistula complications.

Decolorization of reactive textile dyes using water falling film dielectric barrier discharge.

Decolorization of reactive textile dyes Reactive Black 5, Reactive Blue 52, Reactive Yellow 125 and Reactive Green 15 was studied using advanced oxidation processes (AOPs) in a non-thermal plasma reactor, based on coaxial water falling film dielectric barrier discharge (DBD). Used initial dye concentrations in the solution were 40.0 and 80.0mg/L. The effects of different initial pH of dye solutions, and addition of homogeneous catalysts (H(2)O(2), Fe(2+) and Cu(2+)) on the decolorization during subsequent recirculation of dye solution through the DBD reactor, i.e. applied energy density (45-315kJ/L) were studied. Influence of residence time was investigated over a period of 24h. Change of pH values and effect of pH adjustments of dye solution after each recirculation on the decolorization was also tested. It was found that the initial pH of dye solutions and pH adjustments of dye solution after each recirculation did not influence the decolorization. The most effective decolorization of 97% was obtained with addition of 10mM H(2)O(2) in a system of 80.0mg/L Reactive Black 5 with applied energy density of 45kJ/L, after residence time of 24h from plasma treatment. Toxicity was evaluated using the brine shrimp Artemia salina as a test organism.

The effects of hemicelluloses and lignin removal on water uptake behavior of hemp fibers.

This study investigated the individual influences of hemicelluloses and lignin removal on the water uptake behavior of hemp fibers. Hemp fibers with different content of either hemicelluloses or lignin were obtained by chemical treatment with 17.5% sodium hydroxide or 0.7% sodium chlorite. Various tests (capillary rise method, moisture sorption, water retention power) were applied to evaluate the change in water uptake of modified hemp fibers. The obtained results show that when the content of either hemicelluloses or lignin is reduced progressively by chemical treatment, the capillary properties of hemp fibers are improved, i.e. capillary rise height of modified fibers is increased up to 2.7 times in relation to unmodified fibers. Furthermore, hemicelluloses removal increases the moisture sorption and decreases the water retention values of hemp fibers, while lignin removal decreases the moisture sorption and increases the water retention ability of hemp fibers.