Fully bio-based polymer blends: optimization of processing aspects and influence of compatibilizers. Development of strategies to properties improvement

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PLA-PHB polymer blends: study on processing conditions and influence of compatibilizers

In the recent years, the concerns related to the environmental issues stimulated an increasing interest towards the application of biodegradable polymers. However, the use of these renewable resources, in alternative to the conventional petrochemical derived products, has some disadvantages such as limited thermo-mechanical properties. A possible and effective method to overcome some biopolymers limitations is the development of bio-based polymer blends

Miscibility, rheological and thermo-mechanical properties of compatible biopolymer blends: influence of process parameters and natural surfactants

In the recent years, a growing interest in biodegradable plastics as an alternative to the conventional fossil fuel-based polymeric materials was developed. Particularly, PLA is broadly applicable for use as an alternative to petrochemical- derived products. In fact, this polymer is biodegradable and biocompatible and its properties are very similar to those of some synthetic fossil fuel-based polymers. Nevertheless, the range of application of PLA is limited due to its fragility, poor barrier properties and the limited temperature range at which it can be used. Various strategies were proposed to overcome these limitations, such as modifying the chemical structure of the polymer with plasticizers or blending with other polymers. In this work a polylactic acid PLA (70 wt%) and poly- hydroxy butyrate PHB (30 wt%) blend was prepared to obtain a bioplastic with mechanical properties intermediate between those of the two polymers. Specifically, the aims of the work were improve the miscibility of the blend and increase the thermo-mechanical properties. Two different approaches were used to achieve these goals: the study of the influence of process parameters and the introduction of natural compatibilizers in the blend. For the first, a co-rotating twin screw extruder LEISTRITZ ZSE 18/40D (Φ = 18 mm, L/D = 40) was used with three different screw profiles. The investigated formulations were: unfilled PLA/PHB blend and containing 5 wt% of an organo-modified clay (Cloisite 5). In the second part two types of natural surfactants with different chemical structure were used: an ethylene oxide/propylene oxide block copolymer (Synperonic) in the form of flakes and a mixture of two liquid surfactants with a variable lipophilic–hydrophilic index (HLB 12). In this case, PLA/PHB blends were prepared using a DSM Explore twin screw mini-extruder (T=180◦C and screw speed=100 RPM). The investigated formulations were: PLA/PHB with HLB12 ranging from 0.1 wt% to 5 wt% and PLA/PHB with Synperonic in the same range of content. Morphological, thermo-mechanical and rheological analyses were performed on each formulation in both case studies. Firstly, a correlation between the observed morphology and the screw profile was found; in particular, the milder screw profile was the best solution. This result is supported by rheological analyses: an increase of the storage modulus (G’) was obtained after the adding of Cloisite, while the unfilled PLA/PHB blend exhibits a shoulder in the G’ curve caused by the relaxation of the dispersed phase which is in form of droplets, showing the typical rheological response of an immiscible blend. In the second part of the study, the morphological and the rheological analyses showed that HLB 12 was more effective than Synperonic. In fact, the trend of G’ in this last formulation was similar to that of the uncompatibilized blend. Conversely, samples containing HLB 12 showed a different trend of G’ curve and a decrease of the curve slope in the terminal region can be observed, as well. This behaviour can be attributed to the obtainment of a complex morphology, significantly different from that of the neat blend PLA/PHB. Nevertheless, while for HLB 12 system, it was necessary the use of a solvent for their introduction into the extruder, the Synperonic presents the advantage of introducing a solid additive during the process. As far as the thermo-mechanical analyses are concerned, both types of compatibilizers induced excellent mechanical properties at high temperatures, resulting in an increased HDT value that allows to widen the application range of the obtained materials

Rheological behavior and morphology of poly(lactic acid)/low‐density polyethylene blends based on virgin and recycled polymers: Compatibilization with natural surfactants

Blends based on poly(lactic acid) and low-density polyethylene were compatibilized exploiting an innovative strategy involving the introduction of different mixtures of two sustainable liquid surfactants characterized by dissimilar hydrophilic–lipophilic ratios. The compatibilization method was first applied on blends made of virgin polymers, aiming at assessing the surfactant mixture inducing a more significant morphology refinement. Besides, to verify the effectiveness of the selected compatibilizers on recycled materials, the same process was carried out on blends based on reprocessed polymers. Interestingly, the compatibilization caused a significant microstructure modification, with a decrease of 54% of the mean size of the dispersed particles, in the case of virgin polymers-based blends, with a consequent increase of 19% of the dynamic elastic modulus. On the other hand, in the case of reprocessed polymers-based blends, a different compatibilizer efficiency was observed, as the noncompatibilized blend showed amore regular microstructure compared to the compatibilized counterpart

Interactive Effects of Genotype and Molybdenum Supply on Yield and Overall Fruit Quality of Tomato

Molybdenum (Mo) is an essential trace element for plant growth, development, and production. However, there is little known about the function and effects of molybdenum in tomato plants. The present study assessed the influences of different Mo concentrations on four tomato F1 hybrids (“Bybal” F1, “Tyty” F1, “Paride” F1, and “Ornela” F1) grown using a soilless system with different Mo levels [0.0, 0.5 (standard NS), 2.0, and 4.0 μmol L−1, respectively]. The crop yield, plant vigor, fruit skin color, TA, fruit water content as well as the accumulation of SSC, and some antioxidant compounds such as lycopene, polyphenols and ascorbic acid were evaluated. The minerals concentration, including nitrogen (N), Mo, iron (Fe), and copper (Cu), were measured in tomato fruits. Results revealed that tomato plants grown with 2.0 μmol Mo L−1 compared to plants grown with 0.5 μmol Mo L−1 incurred a significant increase of total yield by 21.7%, marketable yield by 9.1%, aboveground biomass by 16.7%, plant height at 50 DAT by 6.5%, polyphenol content by 3.5%, ascorbic acid by 1.0%, SSC by 3.5%, N fruit content by 24.8%, Mo fruit content by 20.0%, and Fe fruit content by 60.5%. However, the Mo concentration did not significantly influence the average fruit weight, b* fruit skin color coordinate and TA. Furthermore, tomato fruits from plants grown with 2.0 μmol Mo L−1 showed a lower Cu fruit content (16.1%) than fruits from plants grown with 0.5 μmol Mo L−1 (standard NS). Consequently, our study highlights the different behavior of the tomato genotypes tested when subjected to different levels of Mo concentration in the nutrient solution. Nevertheless, taking all in consideration our results clearly suggest that a Mo fertilization of 2.0 μmol Mo L−1 effectively enhance crop performance and overall fruit quality of tomato

Genistein reduces angiogenesis and apoptosis in women with endometrial hyperplasia

Roberta Granese,1,* Alessandra Bitto,2,* Francesca Polito,2 Onofrio Triolo,1 Domenico Giordano,1 Angelo Santamaria,1 Francesco Squadrito,2 Rosario D'Anna1 1Department of Paediatric, Gynaecological, Microbiological, and Biomedical Sciences, 2Department of Clinical and Experimental Medicine, Section of Pharmacology, University of Messina, Messina, Italy*These authors contributed equally to this workAbstract: Endometrial hyperplasia without cytological atypia is commonly treated with progestins, but other treatments may be available with equivalent efficacy and reduced side effects. Here, we evaluate the effect of genistein aglycone on angiogenesis and apoptosis-related markers women with endometrial hyperplasia. Premenopausals (n=38) with nonatypical endometrial hyperplasia were administered either genistein aglycone (54 mg/day, n=19) or norethisterone acetate (10 mg/day, n=19) on days 16–25 of the menstrual cycle and evaluated for 6 months. Biopsies were taken during hysteroscopy at baseline and 6 months, and symptoms including excessive uterine bleeding were assessed at baseline and 3 and 6 months following recruitment. The expression of angiogenesis (Vegf), epithelial (Egf and Tgfb), and apoptosis-related (Bax, Bcl-2, and Casp-9) molecules, were assessed in uterine biopsies at baseline and after 6 months of therapy. Follicle-stimulating hormone, luteinizing hormone, estradiol, SHBG, and progesterone levels were also measured. After 6 months, 42% of genistein aglycone-administered patients had a significant improvement of symptoms compared to 47% of norethisterone acetate subjects. No significant differences were noted in hormone levels for any treatment. Gene expression revealed a significant reduction in Vegf, Egf, and Tgfb (P<0.05 versus baseline), and an increase in proapoptotic molecules (Bax and Casp-9), with a concomitant decrease in Bcl-2 values (P<0.05) in both groups. These results suggest that genistein aglycone might be useful for the management of endometrial hyperplasia without atypia in women who cannot or do not wish to be treated with progestin.Keywords: genistein, endometrial hyperplasia, Vegf, Bcl-2, Bax, Casp-

Knowledge, attitudes and practices towards COVID-19 among nursing students of the University of Palermo: results from an online survey

Introduction: The aim of the study was to evaluate the knowledge, attitude and practices towards SARS-CoV-2 among nursing students of University of Palermo during the rapid rise period of the COVID-19 pandemic. Materials and methods: This is cross-sectional study. A survey was provided to all nursing students and consisted of two parts: demographics and Knowledge, Attitude and Practices (KAP) survey. A multivariate linear regression model was used and adjusted Odds Ratios (aOR) are presented. Results: 575 students were interviewed, and their mean age was 22.29 ± 4.2. The overall score indicates good knowledge (p=0.046) and good practices among the four courses of study (p=0.038). Multivariate linear regression showed that Attitude score (b = -0.29; p = 0.024) and Knowledge score (b = 0.10; p = 0.026) adjusted for age, gender, year of study, perceived economic status, perceived health status were significantly associated with Practice score. Conclusion: Our results suggest that proper health education is useful for encouraging optimistic attitudes and maintaining safe practices among future category of nurses

Update on SARS-CoV-2 Omicron Variant of Concern and Its Peculiar Mutational Profile

The process of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genetic diversification is still ongoing and has very recently led to the emergence of a new variant of concern (VOC), defined as Omicron or B.1.1.529. Omicron VOC is the most divergent variant identified so far and has generated immediate concern for its potential capability to increase SARS-CoV-2 transmissibility and, more worryingly, to escape therapeutic and vaccine-induced antibodies. Nevertheless, a clear definition of the Omicron VOC mutational spectrum is still missing. Herein, we provide a comprehensive definition and functional characterization (in terms of infectivity and/or antigenicity) of mutations characterizing the Omicron VOC. In particular, 887,475 SARS-CoV-2 Omicron VOC whole-genome sequences were retrieved from the GISAID database and used to precisely define its specific patterns of mutations across the different viral proteins. In addition, the functional characterization of Omicron VOC spike mutations was finely discussed according to published manuscripts. Lastly, residues characterizing the Omicron VOC and the previous four VOCs (Alpha, Beta, Gamma, and Delta) were mapped on the three-dimensional structure of the SARS-CoV-2 spike protein to assess their localization in the different spike domains. Overall, our study will assist with deciphering the Omicron VOC mutational profile and will shed more light on its clinical implications. This is critical considering that Omicron VOC is currently the predominant variant worldwide. IMPORTANCE The Omicron variant of concern (VOC) has a peculiar spectrum of mutations characterized by the acquisition of mutations or deletions rarely detected in previously identified variants, particularly in the spike glycoprotein. Such mutations, mostly residing in the receptor-binding domain, could play a pivotal role in enhancing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infectivity (by increasing binding affinity for ACE2), jeopardizing spike recognition by therapeutic and vaccine-induced antibodies and causing diagnostic assay failure. To our knowledge, this is one of the first exhaustive descriptions of newly emerged mutations underlying the Omicron VOC and its biological and clinical implications

Quality of residential facilities in Italy: satisfaction and quality of life of residents with schizophrenia spectrum~disorders

Background Recovery and human rights promotion for people with Schizophrenia Spectrum Disorders (SSDs) is fundamental to provide good care in Residential Facilities (RFs). However, there is a concern about rehabilitation ethos in RFs. This study aimed to investigate the care quality of Italian RFs, the quality of life (QoL) and care experience of residents with SSD. Methods Fourty-eight RFs were assessed using a quality assessment tool (QuIRC-SA) and 161 residents with SSD were enrolled. Seventeen RFs provided high intensity rehabilitation (SRP1), 15 medium intensity (SRP2), and 16 medium-low level support (SRP3). Staff-rated tools measured psychiatric symptoms and psychosocial functioning; user-rated tools assessed QoL and satisfaction with services. RFs comparisons were made using ANOVA and Chi-squared. Results Over two-thirds patients (41.5 y.o., SD 9.7) were male. Seventy-six were recruited from SRP1 services, 48 from SRP2, and 27 from SRP3. The lowest QuIRC-SA scoring was Recovery Based Practice (45.8%), and the highest was promotion of Human Rights (58.4%). SRP2 had the lowest QuIRC-SA ratings and SRP3 the highest. Residents had similar psychopathology (p = 0.140) and functioning (p = 0.537). SRP3 residents were more employed (18.9%) than SRP1 (7.9%) or SRP2 (2.2%) ones, and had less severe negative symptoms (p = 0.016) and better QoL (p = 0.020) than SRP2 residents. There were no differences in the RF therapeutic milieu and their satisfaction with care. Conclusions Residents of the lowest supported RFs in Italy had less severe negative symptoms, better QoL and more employment than others. The lowest ratings for Recovery Based Practice across all RFs suggest more work is needed to improve recovery