Polyethylene/poly (lactic acid)/chitosan films, with and without poly (ethylene-g-maleic anhydride) (PEgMA) as compatibilizer, were prepared by extrusion and the degradation behavior under different ...times of standard weathering conditions was analyzed. The materials were characterized by means of infrared spectroscopy, scanning electron microscopy, tensile strength, differential scanning calorimetry and thermogravimetric analysis. It was demonstrated that blends of synthetic and natural polymers have a higher susceptibility to degradation in comparison to neat polyethylene and poly (lactic acid) films. Additionally, it is found that the incorporation of PEgMA into the extruded films apparently favored the polymer degradation, as it deduced from the fall of the mechanical properties when the films are exposed to accelerated weathering simulation.
•Extruded polymeric blends of PE PLA Ch with and without compatibilizer were obtained.•The incorporation of PEgMA makes the films to have a larger degradation.•The accelerated degradation has a strong effect on the mechanical properties of the films.•Morphology of the films was greatly affected by accelerated weathering.•The compatibilizer has no significant effect on the thermic stability of the materials tested.
Pecan nutshells are a solid form of waste obtained from the pecan nut production and they have been explored as an inexpensive filler for incorporation by melt blending into the poly(lactic acid) ...(PLA) matrix. The pecan nutshells contain polyphenols, proteins, tannins, sugars, and lipids; some of these components must be released in order to improve adhesion with a polymeric matrix. The physicochemical characterization of the extruded biocomposites of pecan nutshell powder (PNSP) at 0, 5, and 7.5% wt. with two treatments (untreated and defatted) into PLA is presented in this work. The incorporation of PNSP into the PLA matrix caused a variation in color and density and increased the water absorption. However, some mechanical and thermal parameters of the biocomposites showed a significant decrease. The morphological analysis showed good dispersion and adhesion of the PNSP to the PLA matrix. Based on the results of the characterization, biocomposites formulated with defatted PNSP have a potential to be used as sustainable fillers in PLA biocomposites. These biocomposites have a potential application as food containers, packaging trays, or disposable items.
Development of extruded films composed of biopolymers blended with synthetic polymers aims to minimize the environmental impact of plastic waste‐materials and lead to the sustainable plastic ...industry. To produce biodegradable polymeric blends, the weight content of biopolymers must be maximum without compromising the performance properties of the extruded films. Using a solvent‐free extrusion method, films composed of polypropylene, poly(lactic‐acid), and Chitosan, can be obtained with the use of polypropylene‐graft‐maleic anhydride and glycerol as compatibilizer and plasticizer, respectively. Extruded films with up to a 50 wt% content of biopolymers show acceptable thermal and mechanical properties, where the use of compatibilizer improves the processing characteristics and homogeneous distribution of chitosan throughout the films. Therefore, the extruded films can be considered as alternatives to conventional synthetic‐polymer films, due to their acceptable mechanical and thermal properties with direct potential applications in extrusion‐method mass production of biodegradable polymers.
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•Total disinfection of wastewater was reached with low oxidant and UV-C doses.•Succesful removal of micropollutants achieved in real wastewater plant effluents.•All the applied ...treatments improved the efficiency of UV-C radiation alone.•Sulfate radical based processes performed better than photolysis of H2O2.•SR-AOPs open new strategies for the tertiary treatment of wastewater.
This study explores the enhancement of UV-C tertiary treatment by sulfate radical based Advanced Oxidation Processes (SR-AOPs), including photolytic activation of peroxymonosulfate (PMS) and persulfate (PS) and their photocatalytic activation using Fe(II). Their efficiency was assessed both for the inactivation of microorganisms and the removal or micropollutants (MPs) in real wastewater treatment plant effluents. Under the studied experimental range (UV-C dose 5.7–57 J/L; UV-C contact time 3 to 28 s), the photolysis of PMS and PS (0.01 mM) increased up to 25% the bacterial removal regarding to UV-C system. The photolytic activation of PMS led to the total inactivation of bacteria (≈ 5.70 log) with the highest UV-C dose (57 J/L). However, these conditions were insufficient to remove the MPs, being required oxidant’s dosages of 5 mM to remove above 90% of carbamazepine, diclofenac, atenolol and triclosan. The best efficiencies were achieved by the combination of PMS or PS with Fe(II), leading to the total removal of the MPs using a low UV-C dosage (19 J/L), UV-C contact time (9 s) and reagent’s dosages (0.5 mM). Finally, high mineralization was reached (>50%) with photocatalytic activation of PMS and PS even with low reagent’s dosages.
In the present work, polylactic acid (PLA), elastin and gelatin fibers, containing clindamycin, were prepared to test their potential application as wound dressings. They underwent release studies to ...determine the mechanism of drug release through mathematical models. The fibers have a homogeneous morphology, without pores. The studies of FTIR and thermal analysis corroborate the presence of each of the components in the fibers; the results of the feasibility tests showed encouraging percentages with a viability of 82% after 7 days of direct contact of the HUVEC cells with the membranes. Similarly, cell adhesion assays show the presence of viable and stretched cells on the fibers, the tendency of the cells to position themselves on the fibers and follow this conformation was observed. On the other hand, studies of antimicrobial activity against
S. aureus
show us that in fibers loaded with clindamycin they have inhibition halos greater than 8 mm.
BACKGROUND AND PURPOSEThe correlation between imaging findings and clinical status in patients with idiopathic intracranial hypertension is unclear. We aimed to examine the evolution of idiopathic ...intracranial hypertension-related MR imaging findings in patients treated with venous sinus stent placement. MATERIALS AND METHODSThirteen patients with idiopathic intracranial hypertension (median age, 26.9 years) were assessed for changes in the CSF opening pressure, transstenotic pressure gradient, and symptoms after venous sinus stent placement. Optic nerve sheath diameter, posterior globe flattening and/or optic nerve protrusion, empty sella, the Meckel cave, tonsillar ectopia, the ventricles, the occipital emissary vein, and subcutaneous fat were evaluated on MR imaging before and 6 months after venous sinus stent placement. Data are expressed as percentages, medians, or correlation coefficients (r) with P values. RESULTSAlthough all patients showed significant reductions of the CSF opening pressure (31 versus 21 cm H2O; P = .005) and transstenotic pressure gradient (22.5 versus 1.5 mm Hg; P = .002) and substantial improvement of clinical symptoms 6 months after venous sinus stent placement, a concomitant reduction was observed only for posterior globe involvement (61.5% versus 15.4%; P = .001), optic nerve sheath diameter (6.8 versus 6.1 mm; P < .001), and subcutaneous neck fat (8.9 versus 7.4 mm; P = .001). Strong correlations were observed between decreasing optic nerve sheath diameters and improving nausea/emesis (right optic nerve sheath diameter, r = 0.592, P = .033; left optic nerve sheath diameter, r = 0.718, P = .006), improvement of posterior globe involvement and decreasing papilledema (r = 0.775, P = .003), and decreasing occipital emissary vein diameter and decreasing headache frequency (r = 0.74, P = .035). Decreasing transstenotic pressure gradient at 6 months strongly correlated with decreasing empty sella (r = 0.625, P = .022) and regressing cerebellar ectopia (r = 0.662, P = .019). CONCLUSIONSMost imaging findings persist long after normalization of intracranial pressure and clinical improvement. However, MR imaging findings related to the optic nerve may reflect treatment success.
Phagocytosis is essential to maintain tissue homeostasis in a large number of inflammatory and autoimmune diseases, but its role in the diseased brain is poorly explored. Recent findings suggest that ...in the adult hippocampal neurogenic niche, where the excess of newborn cells undergo apoptosis in physiological conditions, phagocytosis is efficiently executed by surveillant, ramified microglia. To test whether microglia are efficient phagocytes in the diseased brain as well, we confronted them with a series of apoptotic challenges and discovered a generalized response. When challenged with excitotoxicity in vitro (via the glutamate agonist NMDA) or inflammation in vivo (via systemic administration of bacterial lipopolysaccharides or by omega 3 fatty acid deficient diets), microglia resorted to different strategies to boost their phagocytic efficiency and compensate for the increased number of apoptotic cells, thus maintaining phagocytosis and apoptosis tightly coupled. Unexpectedly, this coupling was chronically lost in a mouse model of mesial temporal lobe epilepsy (MTLE) as well as in hippocampal tissue resected from individuals with MTLE, a major neurological disorder characterized by seizures, excitotoxicity, and inflammation. Importantly, the loss of phagocytosis/apoptosis coupling correlated with the expression of microglial proinflammatory, epileptogenic cytokines, suggesting its contribution to the pathophysiology of epilepsy. The phagocytic blockade resulted from reduced microglial surveillance and apoptotic cell recognition receptor expression and was not directly mediated by signaling through microglial glutamate receptors. Instead, it was related to the disruption of local ATP microgradients caused by the hyperactivity of the hippocampal network, at least in the acute phase of epilepsy. Finally, the uncoupling led to an accumulation of apoptotic newborn cells in the neurogenic niche that was due not to decreased survival but to delayed cell clearance after seizures. These results demonstrate that the efficiency of microglial phagocytosis critically affects the dynamics of apoptosis and urge to routinely assess the microglial phagocytic efficiency in neurodegenerative disorders.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Failure of second-generation tyrosine kinase inhibitors (2GTKI) is a challenging situation in patients with chronic myeloid leukemia (CML). Asciminib, recently approved by the US Federal Drug ...Administration, has demonstrated in clinical trials a good efficacy and safety profile after failure of 2GTKI. However, no study has specifically addressed response rates to asciminib in ponatinib pretreated patients (PPT). Here, we present data on responses to asciminib from 52 patients in clinical practice, 20 of them (38%) with prior ponatinib exposure. We analyzed retrospectively responses and toxicities under asciminib and compared results between PPT and non-PPT patients.
After a median follow-up of 30 months, 34 patients (65%) switched to asciminib due to intolerance and 18 (35%) due to resistance to prior TKIs. Forty-six patients (88%) had received at least 3 prior TKIs. Regarding responses, complete cytogenetic response was achieved or maintained in 74% and 53% for non-PPT and PPT patients, respectively. Deeper responses such as major molecular response and molecular response 4.5 were achieved in 65% and 19% in non-PPT versus 32% and 11% in PPT, respectively. Two patients (4%) harbored the T315I mutation, both PPT.
In terms of toxicities, non-PPT displayed 22% grade 3–4 TEAE versus 20% in PPT. Four patients (20% of PPT) suffered from cross-intolerance with asciminib as they did under ponatinib.
Our data supports asciminib as a promising alternative in resistant and intolerant non-PPT patients, as well as in intolerant PPT patients; the resistant PPT subset remains as a challenging group in need of further therapeutic options.
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