Poly(lactic acid), PLA, is a polyester that can be produced from lactic acid derived from renewable resources. This polymer offers attracting uses in packaging industry due to its biodegradability ...and high tensile strength. However, PLA is quite brittle, which limits its applications. To overcome this drawback, PLA was plasticized with epoxy-type plasticizer derived from a fatty acid, octyl epoxy stearate (OES) at different loadings (1, 3, 5, 10, 15, and 20 phr). The addition of OES decreases the glass transition temperature and provides a remarkable increase in elongation at break and impact-absorbed energy. Plasticizer saturation occurs at relatively low concentrations of about 5 phr OES; higher concentration leads to phase separation as observed by field emission scanning electron microscopy (FESEM). Optimum balanced mechanical properties are obtained at relatively low concentrations of OES (5 phr), thus indicating the usefulness of this material as environmentally friendly plasticizer for PLA industrial formulations.
•Thermoplastic starch offers partial miscibility with PLA as evidenced by FESEM.•The addition of 4–6phr MLO leads to an elongation at break of 140–160%.•MLO also provides a compatibilization effect.
...In this work, poly(lactic acid), PLA and thermoplastic starch, TPS blends (with a fixed content of 30wt.% TPS) were prepared by melt extrusion process to increase the low ductile properties of PLA. The TPS used contains an aliphatic/aromatic biodegradable polyester (AAPE) that provides good resistance to aging and moisture. This blend provides slightly improved ductile properties with an increase in elongation at break of 21.5% but phase separation is observed due to the lack of strong interactions between the two polymers. Small amounts of maleinized linseed oil (MLO) can positively contribute to improve the ductile properties of these blends by a combined plasticizing-compatibilizing effect. The elongation at break increases over 160% with the only addition of 6phr MLO. One of the evidence of the plasticizing-compatibilizing effect provided by MLO is the change in the glass transition temperature (Tg) with a decrease of about 10°C. Field emission scanning electron microscopy (FESEM) of PLA-TPS blends with varying amounts of maleinized linseed oil also suggests an increase in compatibility.
Sinus graft infections are rare but serious complications, as they are associated with significant morbidity and sinus graft loss. The aim of this study was to systematically review the management of ...sinus graft infection in order to define which protocols should be implemented. The terms searched in each database were “sinus graft infection management”, “maxillary sinus lift infection”, “maxillary sinus graft infection”, “maxillary sinus elevation infection”, and “maxillary sinus augmentation infection”. The management of the sinus graft infection was assessed. The outcomes evaluated were maxillary sinus health and dental implantation results. The initial search yielded 1190 results. Eighteen articles were included, reporting a total of 3319 patients and 217 sinus graft infections. Drainage was performed with an intraoral approach in 13 studies, an endoscopic approach in two studies, and a combined approach in three studies. In every study, a disease-free sinus was finally obtained in all patients, but the outcomes of the graft and the dental implant were more varied. It is not possible to define the best treatment protocol for sinus graft infections based on the published data, since the level of evidence is poor. Management is very heterogeneous. This review highlights the necessity of surgical treatment associated with antibiotic therapy.
The present work is focused on the development of binary blends from poly(hydroxybutyrate) (PHB) and poly(caprolactone) (PCL). Miscibility, mechanical and thermal properties as well as blends ...morphology are evaluated in terms of the blend composition. Binary PHB–PCL blends were manufactured by melt compounding in a twin screw co-rotating extruder and injection molded. The composition of PHB–PCL covered the full range between individual polymers at 25 wt% increments. The obtained results show that PCL acts as an impact modifier, thus leading to an increase in flexibility and ductility as the PCL content in the PHB–PCL blends increases with a noticeable increase in elongation at break and on the energy absorption in impact conditions. The tensile strength and the elastic modulus decrease with increasing PCL content in the PHB–PCL blends; nevertheless, the flexural strength and the flexural modulus reach the highest values for the PHB–PCL blends containing 25 wt% PCL, with a remarkable decrease over this composition. The analysis of fractured surfaces by field emission scanning electron microscopy and thermal properties obtained by differential scanning calorimetry (DSC) and TGA give clear evidences of the immiscibility of these two biodegradable polymers. Additionally, DSC results showed an increase in crystallinity of both PHB and PCL with regard to individual polymers for PHB–PCL blends containing 25 wt% PCL. Furthermore, an increase in the degradation onset (
T
0
) of about 30 °C higher was detected for the same blends. Dynamic mechanical thermal analysis showed slightly shifted glass transition temperatures of each individual polymer, thus indicating that although both PHB and PCL are not fully miscible, some interactions between them occur.
Schizophrenia (SZ) is a severe neuropsychiatric disorder associated with disrupted connectivity within the thalamic-cortico-cerebellar network. Resting-state functional connectivity studies have ...reported thalamic hypoconnectivity with the cerebellum and prefrontal cortex as well as thalamic hyperconnectivity with sensory cortical regions in SZ patients compared with healthy comparison participants (HCs). However, fundamental questions remain regarding the clinical significance of these connectivity abnormalities.
Resting state seed-based functional connectivity was used to investigate thalamus to whole brain connectivity using multi-site data including 183 SZ patients and 178 matched HCs. Statistical significance was based on a voxel-level FWE-corrected height threshold of p < 0.001. The relationships between positive and negative symptoms of SZ and regions of the brain demonstrating group differences in thalamic connectivity were examined.
HC and SZ participants both demonstrated widespread positive connectivity between the thalamus and cortical regions. Compared with HCs, SZ patients had reduced thalamic connectivity with bilateral cerebellum and anterior cingulate cortex. In contrast, SZ patients had greater thalamic connectivity with multiple sensory-motor regions, including bilateral pre- and post-central gyrus, middle/inferior occipital gyrus, and middle/superior temporal gyrus. Thalamus to middle temporal gyrus connectivity was positively correlated with hallucinations and delusions, while thalamus to cerebellar connectivity was negatively correlated with delusions and bizarre behavior.
Thalamic hyperconnectivity with sensory regions and hypoconnectivity with cerebellar regions in combination with their relationship to clinical features of SZ suggest that thalamic dysconnectivity may be a core neurobiological feature of SZ that underpins positive symptoms.
This research work aims at the compatibilization of poly(lactic acid)/poly(butylene adipate-co-terephthalate), PLA/PBAT binary blends by using cottonseed oil derivatives, i.e. epoxidized (ECSO) and ...maleinized (MCSO) cottonseed oil. The potential of these vegetable oil-based compatibilizers are compared versus the effects of a conventional styreneacrylic oligomer. The base PLA/PBAT binary blend composition was 80 wt% PLA/20 wt% PBAT and the amount of compatibilizer was set to 1 and 7.5 wt%. The effects of the different compatibilizers were evaluated on PLA/PBAT films in terms of mechanical and thermal properties as well as blend's morphology by field emission scanning electron microscopy (FESEM). Complementary, biodisintegration tests in controlled compost soil and surface properties were evaluated to assess the effects of the compatibilizers. Addition of 1 wt% ECSO and MCSO led to a remarkable increase in the elongation at break up to values over 100% with regard to neat PLA. Despite this, maximum elongation at break was obtained for the compatibilized PLA/PBAT blend with 7.5 wt% MCSO, reaching values of about 321.2% respect neat PLA keeping mechanical resistant properties, such as Young's modulus and tensile strength, at high levels. Therefore, vegetable oil-derived compatibilizers stand out as environmentally friendly additives for PLA/PBAT binary blends with improved properties.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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