Challenging Isodimorphism Concepts: Formation of Three Crystalline Phases in Poly(hexamethylene-ran-octamethylene carbonate) Copolymers.

In this work, poly(hexamethylene-ran-octamethylene carbonate) copolycarbonates were synthesized by melt polycondensation in a wide range of compositions. The copolymers displayed some of the characteristic isodimorphic thermal behavior, such as crystallization for all the compositions and a pseudoeutectic behavior of the melting temperature (Tm) versus composition. The pseudoeutectic point was located at 33 mol % poly(octamethylene carbonate) (POC) content (i.e., corresponding to the PH67O33C copolymer). Surprisingly, the crystallinities (Xc) for a wide range of copolymer compositions were higher than those of the parent components, a phenomenon that has not been observed before in isodimorphic random copolymers. The structural characterization, performed by wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering experiments, revealed unexpected results depending on composition. On the one hand, the poly(hexamethylene carbonate) (PHC)- and POC-rich copolymers crystallize in PHC- and POC-type crystals, as expected. Moreover, upon cooling and heating, in situ WAXS experiments evidenced that these materials undergo reversible solid-solid transitions [δ-α (PHC) and δ-α-ß (POC)] present in the parent components but at lower temperatures. On the other hand, a novel behavior was found for copolymers with 33-73 mol % POC (including the pseudoeutectic point), which are those with higher crystallinities than the parent components. For these copolymers, a new crystalline phase that is different from that of both homopolymers was observed. The in situ WAXS results for these copolymers confirmed that this novel phase is stable upon cooling and heating and does not show any crystallographic feature of the parent components or their solid-solid transitions. FTIR experiments confirmed this behavior, revealing that the new phase adopts a polyethylene-like chain conformation that differs from the trans-dominant ones exhibited by the parent components. This finding challenges the established concepts of isodimorphism and questions whether a combination of crystallization modes (isodimorphism and isomorphism) is possible in the same family of random copolymers just by changing the composition.

The Relevance of Telomerase and Telomere-Associated Proteins in B-Acute Lymphoblastic Leukemia.

Telomeres and telomerase are closely linked to uncontrolled cellular proliferation, immortalization and carcinogenesis. Telomerase has been largely studied in the context of cancer, including leukemias. Deregulation of human telomerase gene hTERT is a well-established step in leukemia development. B-acute lymphoblastic leukemia (B-ALL) recovery rates exceed 90% in children; however, the relapse rate is around 20% among treated patients, and 10% of these are still incurable. This review highlights the biological and clinical relevance of telomerase for B-ALL and the implications of its canonical and non-canonical action on signaling pathways in the context of disease and treatment. The physiological role of telomerase in lymphocytes makes the study of its biomarker potential a great challenge. Nevertheless, many works have demonstrated that high telomerase activity or hTERT expression, as well as short telomeres, correlate with poor prognosis in B-ALL. Telomerase and related proteins have been proven to be promising pharmacological targets. Likewise, combined therapy with telomerase inhibitors may turn out to be an alternative strategy for B-ALL.

The Influence of L-menthol on Time Trial Running Performance in Recreational Runners.

Purpose: This study investigated the effects of combined mouth rinse and topical application of L-menthol on perceptual responses and running performance under thermoneutral conditions (22 ± 2°C and 30-60% relative humidity). Methods: Twelve recreational male runners (age: 31.7 ± 3.8 years; age range: 27-39 years) completed a familiarization, a control test (CON) and two maximal 10-km time trials (counterbalanced randomized crossover design) performed in different days with a non-thermal cooling intervention (combined application of a L-menthol mouth rinse and topical L-menthol gel - MEN) or placebo (PLA). Performance and perceptual measures (thermal sensation, thermal comfort, ratings of perceived exertion and affective response) were recorded for every km completed in the 10-km test. Results: Performance time was lower in MEN (P = 0.03) and PLA (P = 0.003) compared to CON, but no differences were found between MEN vs PLA (P = 1.00). All perceptual responses increased over time in all conditions (P < 0.0001), but only the thermal sensation was lower (P = 0.01) in the MEN compared to CON. Conclusion: L-menthol strategies promote fresh sensations and may improve running performance in 10-km time trial in recreational runners, but the performance improvement could mainly be due to a placebo effect.

Multiparametric flow cytometry directing the evaluation of CRLF2 rearrangements and JAK2 status in pediatric B cell precursor acute lymphoblastic leukemia.

INTRODUCTION: This study aimed to determine whether cytokine receptor-like factor 2 (CRLF2) antigen expression evaluated using multiparametric flow cytometry (MFC) could predict the genotype of CRLF2 and Janus kinase 2 (JAK2) status for application in the diagnosis of pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL). METHODS: A total of 321 BCP-ALL bone marrow samples were collected, 291 at diagnosis and 13 at first relapse, while 17 samples were excluded due to low cellular viability. The CRLF2 antigen expression was evaluated using flow cytometry (percentage of positivity and median fluorescence intensity [MFI]). The CRLF2 transcript levels were assessed via quantitative reverse transcription polymerase chain reaction using SYBR Green. The CRLF2 rearrangements (CRLF2-r) were identified using the CRLF2 break-apart probe via fluorescence in situ hybridization. Sanger sequencing was performed to identify the JAK2 exon 16 mutations. RESULTS: We observed that 60 of the 291 cases (20.6%) presented CRLF2 antigen positivity, whereas the CRLF2 transcript overexpression was found in 19 of 113 cases (16.8%). The JAK2 mutation was found in four out of 116 cases (3.4%), all of which had CRLF2 ≥10% of positive cells and intermediate or high MFI (p < 0.0001). In addition, in the 13 cases with the CRLF2-r, a positive correlation was found with the CRLF2 antigen intermediate (61.5%) MFI (p = 0.017). Finally, the CRLF2-positive antigen was identified in the BCP-ALL subclones. CONCLUSION: The identification of the CRLF2 antigen using the MFC, based on the percentage of positivity and MFI values, is a useful tool for predicting JAK2 mutations and CRLF2-r.

Risco de contaminação por aerossóis em consultório odontológico e comparação a procedimentos eletivos / Risk of contamination by aerosols in dental offices and comparison to elective procedures / Riesgo de contaminación por aerosoles en consultorios dentales y comparación con procedimientos electivos

Durante os procedimentos odontológicos, os profissionais devem se preocupar com a disseminação e a formação de aerossóis, sendo essa uma rota de transmissão potencial. O objetivo foi demonstrar o risco de contaminação por aerossóis da cavidade bucal durante o atendimento em consultórios odontológicos e comparar cinco procedimentos eletivos, utilizou-se um marcador (corante alimentício) na água do reservatório do equipamento odontológico para identificar a contaminação por produção de aerossóis. Estabeleceu-se os círculos A, B e C com raios de 50, 100 e 150 cm, respectivamente, a partir do ponto central do encosto da cabeça na cadeira odontológica. Estabeleceu-se um planejamento fatorial e teste de Tukey para comparação das médias dos pontos de contaminação e para os pontos não contáveis de contaminação aplicou-se a Análise de Componentes Principais (ACP). O tipo de procedimento e a interação entre o local e tipo de procedimento não se mostraram estatisticamente significativos, mas verificou-se maior incidência significativa no círculo A (raio de 50 cm). Aplicando a ACP foi possível relacionar a contaminação do tórax do paciente e da ponta do sugador com os procedimentos de Ultrassom e Incisivo Central Superior, assim como a relação da contaminação do jaleco do cirurgião dentista e da ponta da caneta de alta rotação com os procedimentos de Primeiro Molar Superior, Primeiro Molar Inferior e Incisivo Central Inferior. Precauções para minimizar a contaminação e o espalhamento dos aerossóis devem ser utilizadas nos atendimentos odontológicos para diminuir os riscos de contaminação da equipe profissional, dos pacientes e do ambiente.

During dental procedures, professionals should be concerned with the spread and formation of aerosols, as this is a potential transmission route. The objective was to demonstrate the risk of contamination by aerosols in the oral cavity during care in dental offices and to compare five elective procedures. Circles A, B and C were established with radii of 50, 100 and 150 cm, respectively, from the central point of the headrest on the dental chair. A factorial design and Tukey's test were established to compare the averages of the contamination points and for the non-countable points of contamination, Principal Component Analysis (PCA) was applied. The type of procedure and the interaction between the location and the type of procedure were not statistically significant, but there was a significant higher incidence in circle A (50 cm radius). Applying PCA, it was possible to relate the contamination of the patient's thorax and the tip of the sucker with the Ultrasound and Upper Central Incisor procedures, as well as the relationship of contamination of the dentist's coat and the tip of the high-speed pen with the procedures of Upper First Molar, Lower First Molar and Lower Central Incisor. Precautions to minimize contamination and the spread of aerosols must be used in dental care to reduce the risk of contamination of the professional team, patients and the environment.

Durante los procedimientos dentales, los profesionales deben preocuparse por la propagación y formación de aerosoles, ya que esta es una ruta potencial de transmisión. El objetivo fue demostrar el riesgo de contaminación por aerosoles en la cavidad bucal durante la atención en los consultorios odontológicos y comparar cinco procedimientos electivos. Se establecieron círculos A, B y C con radios de 50, 100 y 150 cm, respectivamente, desde el punto central del reposacabezas del sillón dental. Se estableció un diseño factorial y la prueba de Tukey para comparar los promedios de los puntos de contaminación y para los puntos de contaminación no contables se aplicó el Análisis de Componentes Principales (PCA). El tipo de procedimiento y la interacción entre la ubicación y el tipo de procedimiento no fueron estadísticamente significativos, pero hubo una incidencia significativamente mayor en el círculo A (50 cm de radio). Aplicando PCA se logró relacionar la contaminación del tórax del paciente y la punta de la ventosa con los procedimientos de Ultrasonido e Incisivo Central Superior, así como la relación de la contaminación de la bata del odontólogo y la punta del bolígrafo de alta velocidad con los procedimientos de Primer Molar Superior, Primer Molar Inferior e Incisivo Central Inferior. Precauciones para minimizar la contaminación y la propagación de aerosoles deben ser utilizados en la atención odontológica para reducir el riesgo de contaminación del equipo profesional, los pacientes y el medio ambiente.

Multiparametric flow cytometry directing the evaluation of CRLF2 rearrangements and JAK2 status in pediatric B cell precursor acute lymphoblastic leukemia

Asbtract Introduction This study aimed to determine whether cytokine receptor-like factor 2 (CRLF2) antigen expression evaluated using multiparametric flow cytometry (MFC) could predict the genotype of CRLF2 and Janus kinase 2 (JAK2) status for application in the diagnosis of pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL). Methods A total of 321 BCP-ALL bone marrow samples were collected, 291 at diagnosis and 13 at first relapse, while 17 samples were excluded due to low cellular viability. The CRLF2 antigen expression was evaluated using flow cytometry (percentage of positivity and median fluorescence intensity [MFI]). The CRLF2 transcript levels were assessed via quantitative reverse transcription polymerase chain reaction using SYBR Green. The CRLF2 rearrangements (CRLF2-r) were identified using the CRLF2 break-apart probe via fluorescence in situ hybridization. Sanger sequencing was performed to identify the JAK2 exon 16 mutations. Results We observed that 60 of the 291 cases (20.6%) presented CRLF2 antigen positivity, whereas the CRLF2 transcript overexpression was found in 19 of 113 cases (16.8%). The JAK2 mutation was found in four out of 116 cases (3.4%), all of which had CRLF2 ≥10% of positive cells and intermediate or high MFI (p < 0.0001). In addition, in the 13 cases with the CRLF2-r, a positive correlation was found with the CRLF2 antigen intermediate (61.5%) MFI (p= 0.017). Finally, the CRLF2-positive antigen was identified in the BCP-ALL subclones. Conclusion The identification of the CRLF2 antigen using the MFC, based on the percentage of positivity and MFI values, is a useful tool for predicting JAK2 mutations and CRLF2-r.

Plantas alimentícias não convencionais: revisão / Non-conventional food plants: review / Plantas alimenticias no convencionales: revisión

As plantas alimentícias não convencionais (PANCs) são hortaliças nativas, normalmente encontradas em calçadas ou terrenos abandonados, sempre fizeram parte do cardápio dos antepassados. No entanto, com a modernização da agricultura e do êxodo rural, seu consumo foi esquecido de ser repassado para as gerações futuras. O objetivo deste estudo consistiu em realizar um levantamento bibliográfico sobre as plantas alimentícias não convencionais (PANCs), sua importância na alimentação e farmacológica. A metodologia consistiu na realização de levantamento bibliográfico, com as principais plantas utilizadas como alimento pelos antepassados sendo as plantas Pereskia aculeata Miller, Basella alba, Sonchus oleraceus, Stachys byzantina, Taraxacum Officinale, Xanthosoma sagittifolium, Dioscorea bulbifera, Physalis angulata, Acmella oleracea, Tropaeolum majus. Através deste estudo pode-se constatar que estas plantas são úteis, pois além de apresentar valor nutricional e a sua utilização na alimentação, também são utilizadas como como plantas medicinais, devido à presença de compostos ativos responsáveis pela ação biológica.

Unconventional food plants (PANCs) are native vegetables, usually found on sidewalks or abandoned land, have always been part of the ancestors' menu. Nonetheless, with the modernization of agriculture and the rural exodus, its consumption was forgotten to be passed on to future generations. The objective of this study was to carry out a bibliographic survey on unconventional food plants (PANCs), their importance in food and pharmacology. The methodology consisted of carrying out a bibliographic survey, with the main plants used as food by the ancestors being the plants Pereskia aculeata Miller, Basella alba, Sonchus oleraceus, Stachys byzantina, Taraxacum Officinale, Xanthosoma sagittifolium, Dioscorea bulbifera, Physalis angulata, Acmella oleracea, Tropaeolum majus. Through this study it can be seen that these plants are useful, because in addition to presenting nutritional value and their use in food, they are also used as medicinal plants, due to the presence of active compounds responsible for biological action.

Las plantas alimenticias no convencionales (PANC, por sus siglas en inglés) son vegetales nativos, que generalmente se encuentran en las aceras o en terrenos abandonados, y siempre han sido parte del menú de los antepasados. Sin embargo, con la modernización de la agricultura y el éxodo rural, su consumo quedó en el olvido para pasar a las generaciones futuras. El objetivo de este estudio fue realizar un levantamiento bibliográfico sobre las plantas alimenticias no convencionales (PANCs), su importancia en la alimentación y farmacología. La metodología consistió en realizar un levantamiento bibliográfico, siendo las principales plantas utilizadas como alimento por los ancestros las plantas Pereskia aculeata Miller, Basella alba, Sonchus oleraceus, Stachys byzantina, Taraxacum Officinale, Xanthosoma sagittifolium, Dioscorea bulbifera, Physalis angulata, Acmella oleracea , Tropaeolum mayor. A través de este estudio se puede apreciar que estas plantas son útiles, pues además de presentar valor nutritivo y su uso en la alimentación, también son utilizadas como plantas medicinales, debido a la presencia de compuestos activos responsables de la acción biológica.

Superalimentos: fundamentação científica / Superfoods: scientific basis / Superalimentos: base científica

Este trabalho tem por objetivo realizar uma pesquisa visando a fundamentação científica dos superalimentos. Embora não existam diretrizes oficiais para o que constitui um "superalimento", geralmente está denominação se aplica a produtos alimentícios que contêm grandes quantidades de nutrientes específicos (por exemplo, antioxidantes, vitaminas e minerais). Estes bioativos atuam como potenciais agentes de prevenção e complementam os tratamentos de doenças crônicas como síndrome metabólica, diabetes, hipertensão, inflamações, doenças autoimunes entre outras. Como exemplos de superalimentos, encontram-se os brotos, sementes, vegetais, frutas, cúrcuma, chá verde, algas como a espirulina, alho, gengibre, cacau, pólen, geleia real, mel de abelha, coco e açaí. Nesse sentido, outros estudos poderiam ser realizados para investigar como estão sendo compreendidos os superalimentos dentro do campo científico.

This work aims to carry out research aiming at the scientific foundation of superfoods. While there are no official guidelines for what constitutes a "superfood", this designation generally applies to food products that contain large amounts of specific nutrients (eg, antioxidants, vitamins and minerals). These bioactives act as potential preventive agents and complement treatments for chronic diseases such as metabolic syndrome, diabetes, hypertension, inflammation, autoimmune diseases, among others. As examples of superfoods, there are sprouts, seeds, vegetables, fruits, turmeric, green tea, algae such as spirulina, garlic, ginger, cocoa, pollen, royal jelly, bee honey, coconut and açaí. In this sense, other studies could be carried out to investigate how superfoods are being understood within the scientific field.

El objetivo de este trabajo es realizar una investigación sobre la base científica de los superalimentos. Aunque no existen directrices oficiales sobre lo que constituye un "superalimento", esta denominación se aplica generalmente a los productos alimenticios que contienen grandes cantidades de nutrientes específicos (por ejemplo, antioxidantes, vitaminas y minerales). Estos bioactivos actúan como agentes potenciales para prevenir y complementar los tratamientos de enfermedades crónicas como el síndrome metabólico, la diabetes, la hipertensión, la inflamación, las enfermedades autoinmunes y otras. Como ejemplos de superalimentos, están los germinados, las semillas, las verduras, las frutas, la cúrcuma, el té verde, las algas como la espirulina, el ajo, el jengibre, el cacao, el polen, la jalea real, la miel de abeja, el coco y el acai. En este sentido, se podrían realizar otros estudios para investigar cómo se entienden los superalimentos dentro del ámbito científico.

A sensitive and inexpensive high-resolution melting-based testing algorithm for diagnosis of transient abnormal myelopoiesis and myeloid leukemia of Down syndrome.

Patients with Down syndrome (DS) are commonly affected by a pre-leukemic disorder known as transient abnormal myelopoiesis (TAM). This condition usually undergoes spontaneous remission within the first 2 months after birth; however, in children under 5, 20%-30% of cases evolve to myeloid leukemia of Down syndrome (ML-DS). TAM and ML-DS are caused by co-operation between trisomy 21 and acquired mutations in the GATA1 gene. Currently, only next-generation sequencing (NGS)-based methodologies are sufficiently sensitive for diagnosis in samples with small GATA1 mutant clones (≤10% blasts). Alternatively, this study presents research on a new, fast, sensitive, and inexpensive high-resolution melting (HRM)-based diagnostic approach that allows the detection of most cases of GATA1 mutations, including silent TAM. The algorithm first uses flow cytometry for blast count, followed by HRM and Sanger sequencing to search for mutations on exons 2 and 3 of GATA1. We analyzed 138 samples of DS patients: 110 of asymptomatic neonates, 10 suspected of having TAM, and 18 suspected of having ML-DS. Our algorithm enabled the identification of 33 mutant samples, among them five cases of silent TAM (5/110) and seven cases of ML-DS (7/18) with blast count ≤10%, in which GATA1 alterations were easily detected by HRM. Depending on the type of genetic variation and its location, our methodology reached sensitivity similar to that obtained by NGS (0.3%) at a considerably reduced time and cost, thus making it accessible worldwide.

A Review on Current Strategies for the Modulation of Thermomechanical, Barrier, and Biodegradation Properties of Poly (Butylene Succinate) (PBS) and Its Random Copolymers.

The impact of plastics on the environment can be mitigated by employing biobased and/or biodegradable materials (i.e., bioplastics) instead of the traditional "commodities". In this context, poly (butylene succinate) (PBS) emerges as one of the most promising alternatives due to its good mechanical, thermal, and barrier properties, making it suitable for use in a wide range of applications. Still, the PBS has some drawbacks, such as its high crystallinity, which must be overcome to position it as a real and viable alternative to "commodities". This contribution covers the actual state-of-the-art of the PBS through different sections. The first section reviews the different synthesis routes, providing a complete picture regarding the obtained molecular weights and the greener alternatives. Afterward, we examine how different strategies such as random copolymerization and the incorporation of fillers can effectively modulate PBS properties to satisfy the needs for different applications. The impact of these strategies is evaluated in the crystallization behavior, crystallinity, mechanical and barrier properties, and biodegradation. The biodegradation is carefully analyzed, highlighting the wide variety of methodologies existing in the literature to measure PBS degradation through different routes (hydrolytic, enzymatic, and soil).

The chemical composition and antioxidant activity of mandaçaia (melipona quadrifasciata) geopropolis varies more due to region than month of collection.

Stingless bees are responsible for pollinating up to 90% of Brazilian flora, so their study is of commercial and ecological importance. Stingless bees mix plant resins with wax and soil, forming geopropolis. Studies of the variability in composition and activity due to species, place and season of collection are lacking. Yield, total phenolic and flavonoid content, and antioxidant activity (via DPPH) of the extracts of fifteen M. quadrifasciata (Mandaçaia) geopropolis samples collected over a year in the State of São Paulo, Brazil, as well as two samples from different regions of the state of Minas Gerais in Brazil were compared. Composition was determined by ultra-high-resolution liquid chromatography and mass spectrometry, identifying 16 compounds. The month and region of collection affected the available plant resins and influenced their yield, composition and antioxidant capacity. Depending on the place of collection, M. quadrifasciata geopropolis is a promising natural source of antioxidant phenolic compounds.

Polycaprolactone Adsorption and Nucleation onto Graphite Nanoplates for Highly Flexible, Thermally Conductive, and Thermomechanically Stiff Nanopapers.

Free-standing nanopapers based on graphene and its related materials have been widely studied and proposed for flexible heat spreader applications. Given that these materials are typically brittle, this work reports the exploitation of polycaprolactone (PCL) as a polymer binder to enhance resistance and flexibility of nanopapers based on graphite nanoplates (GNP), while maintaining a high thermal conductivity. Properties of nanopapers appear to correlate with the excellent PCL adhesion and strong nucleation of the surface of GNP flakes. Furthermore, different crystalline populations were observed for PCL within the nanopaper and were investigated in detail via differential scanning calorimetry advanced techniques and X-ray diffraction. These demonstrated the coexistence of conventional unoriented PCL crystals, oriented PCL crystals obtained as a consequence of the strong nucleation effect, and highly stable PCL fractions explained by the formation of crystalline pre-freezing layers, the latter having melting temperatures well above the equilibrium melting temperature for pristine PCL. This peculiar crystallization behavior of PCL, reported in this paper for the first time for a tridimensional structure, has a direct impact on material properties. Indeed, the presence of high thermal stability crystals, strongly bound to GNP flakes, coexisting with the highly flexible amorphous fraction, delivers an ideal solution for the strengthening and toughening of GNP nanopapers. Thermomechanical properties of PCL/GNP nanopapers, investigated both on a heating ramp and by creep tests at high temperatures, demonstrated superior stiffness well above the conventional melting temperature of PCL. At the same time, a thermal conductivity > 150 W/m·K was obtained for PCL/GNP nanopapers, representing a viable alternative to traditional metals in terms of heat dissipation, while affording flexibility and light weight, unmatched by conventional thermally conductive metals or ceramics. Besides the obtained performance, the formation of polymer crystals that are stable above the equilibrium melting temperature constitutes a novel approach in the self-assembly of highly ordered nanostructures based on graphene and related materials.

Accelerating the crystallization kinetics of linear polylactides by adding cyclic poly (L-lactide): Nucleation, plasticization and topological effects.

Polylactide is one of the most versatile biopolymers, but its slow crystallization limits its temperature usage range. Hence finding ways to enhance it is crucial to widen its applications. Linear and cyclic poly (L-lactide) (l-PLLA and c-PLLA) of similarly low molecular weights (MW) were synthesized by ring-opening polymerization of L-lactide, and ring-expansion methodology, respectively. Two types of blends were prepared by solution mixing: (a) l-PLLA/c-PLLA, at extreme compositions (rich in linear or in cyclic chains), and (b) blends of each of these low MW materials with a commercial high MW linear PLA. The crystallization of the different blends was evaluated by polarized light optical microscopy and differential scanning calorimetry. It was found, for the first time, that in the l-PLLA rich blends, small amounts of c-PLLA (i.e., 5 and 10 wt%) increase the nucleation density, nucleation rate (1/τ0), spherulitic growth rate (G), and overall crystallization rate (1/τ50%), when compared to neat l-PLLA, due to a synergistic effect (i.e., nucleation plus plasticization). In contrast, the opposite effect was found in the c-PLLA rich blends. The addition of small amounts of l-PLLA to a matrix of c-PLLA chains causes a decrease in the nucleation density, 1/τ0, G, and 1/τ50% values, due to threading effects between cyclic and linear chains. Small amounts of l-PLLA and c-PLLA enhance the crystallization ability of a commercial high MW linear PLA without affecting its melting temperature. The l-PLLA only acts as a plasticizer for the PLA matrix, whereas c-PLLA has a synergistic effect in accelerating the crystallization of PLA that goes beyond simple plasticization. The addition of small amounts of c-PLLA affects not only PLA crystal growth but also its nucleation due to the unique cyclic chains topology.

Effect of the Crystallization Conditions on the Exclusion/Inclusion Balance in Biodegradable Poly(butylene succinate-ran-butylene adipate) Copolymers.

Biomedical applications of polymers require precise control of the solid-state structure, which is of particular interest for biodegradable copolymers. In this work, we evaluated the influence of crystallization conditions on the comonomer exclusion/inclusion balance of biodegradable poly(butylene succinate-ran-butylene adipate) (PBSA) isodimorphic random copolymers. Regardless of the crystallization conditions, the copolymers retain their isodimorphic character, displaying a pseudo-eutectic behavior with crystallization in the entire composition range. This illustrates the thermodynamic nature of the isodimorphic behavior for PBSA random copolymers. However, depending on the composition, the crystallization conditions affect the exclusion/inclusion balance of the comonomers. Fast cooling favors butylene adipate (BA) inclusion inside the poly(butylene succinate) (PBS) crystals, whereas isothermal crystallization strongly limits it. PBA-rich compositions behave differently. Both fast and slow crystallization formed the ß-phase, whereas BS unit inclusion is favored independently of the cooling conditions. During successive self-nucleation and annealing, the BA inclusion is intermediate between non-isothermal and isothermal conditions, while the crystalline structure of the PBA phase changes from the ß-phase to the more stable α-phase. We propose a simple crystallographic model to explain the changes in the unit cell dimension of the copolymers.

Effects of Hairy Nanoparticles on Polymer Crystallization Kinetics.

We previously showed that nanoparticles (NPs) could be ordered into structures by using the growth rate of polymer crystals as the control variable. In particular, for slow enough spherulitic growth fronts, the NPs grafted with amorphous polymer chains are selectively moved into the interlamellar, interfibrillar, and interspherulitic zones of a lamellar morphology, specifically going from interlamellar to interspherulitic with progressively decreasing crystal growth rates. Here, we examine the effect of NP polymer grafting density on crystallization kinetics. We find that while crystal nucleation is practically unaffected by the presence of the NPs, spherulitic growth, final crystallinity, and melting point values decrease uniformly as the volume fraction of the crystallizable polymer, poly(ethylene oxide) or PEO, ϕPEO, decreases. A surprising aspect here is that these results are apparently unaffected by variations in the relative amounts of the amorphous polymer graft and silica NPs at constant ϕ, implying that chemical details of the amorphous defect apparently only play a secondary role. We therefore propose that the grafted NPs in this size range only provide geometrical confinement effects which serve to set the crystal growth rates and melting point depressions without causing any changes to crystallization mechanisms.

Educação, mídia e internet: desafios e possibilidades a partir do conceito de letramento digital / Education, media and internet: challenges and possibilities based on the concept of digital literacy / Educación, medios de comunicación e internet: desafíos yposibilidades a partir del concepto de alfabetización digital

A forte presença da comunicação digital no cotidiano das escolas demanda uma educação que ocupe o lugar de crítica e mediação diante dos discursos em circulação. Alinhados com essa percepção e embasados pela literatura e pelas pesquisas recentes, discutiremos o conceito de letramento digital (digital literacy), que envolve o desenvolvimento de competências para o uso crítico e informado dos meios digitais, em especial, no contexto das metodologias ativas de aprendizagem. As considerações finais apontam para os desafios encontrados com o objetivo de se estabelecer um diálogo virtuoso entre Educação e Comunicação e sugerem como possíveis caminhos o uso das TICs que enfatize seu caráter comunicacional, assim como o diálogo com os conceitos morenianos de espontaneidade e criatividade.

The strong presence of digital communication in school’s routine demands an education that occupies the place of criticism and mediation before the speeches in use. Aligned with this perception and base on literature and recent studies, we will discuss the concept of digital literacy, which involves the development of skills for a critical and knowledgeable use of digital media, especially the context of learning active methods. The final considerations point out the challenges encountered to establish a virtuous dialogue between Education and Communication and suggest as possible ways the use of ICTs that emphasizes its communicational character, as well as the dialogue with the Morenian concepts of spontaneity and creativity

La fuerte presencia de la comunicación digital en el cotidiano de las escuelas demanda una educación que ocupe el lugar de crítica y mediación ante los discursos en circulación. Ajustados a esa concepción y basados en la literatura y las investigaciones recientes, discutiremos el concepto de alfabetización digital (digital literacy), que implica el desarrollo de aptitudes para el empleo crítico y actualizado de los medios digitales, en particular, en el contexto de las metodologías activas de aprendizaje. Las consideraciones finales apuntan a los desafíos encontrados con el objetivo de establecer un diálogo virtuoso entre Educación y Comunicación y sugieren como posibles caminos el uso de las TICs que enfatiza su carácter comunicacional, así como el diálogo con los conceptos morenianos de espontaneidad y creatividad.

Benefits of Ascorbic Acid in Association with Low-Dose Benznidazole in Treatment of Chagas Disease.

The acute phase of Chagas disease (CD) is characterized by high parasitic proliferation and intense inflammation, exacerbating the generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS). These reactive molecules are also increased by the metabolism of the nitroheterocyclic compounds benznidazole (BZ) and nifurtimox, the only drugs available for the treatment of CD. This oxidative environment, associated with the intracellular multiplication of Trypanosoma cruzi, leads to tissue destruction, triggering the pathogenic process. Both drugs have limited efficacy and serious side effects, which demonstrates the need to seek alternative therapies. Due to the difficulty in developing new drugs, reviewing therapeutic regimens appears advantageous, and the use of BZ in low doses associated with antioxidants, such as ascorbic acid (AA), would be a valid alternative to attenuate oxidative stress. In our in vivo studies, mice receiving the combination of 7.14 mg/kg of body weight/day AA and 10 mg/kg/day BZ10 (AA+BZ10) showed a reduction in parasitemia that was more effective than that with those receiving BZ or AA alone. The combined treatment was effective in decreasing intracellular ROS and lipid peroxidation in cardiac tissue. Histological and PCR analyzes showed that AA also reduced the cardiac parasitism. However, the greatest benefit was seen in AA+BZ10 group, since cardiac inflammation was significantly reduced. In addition, the combined therapy prevented the hepatic damage induced by the infection. Our findings suggest that AA combined with a low dose of BZ may improve the trypanocidal activity and attenuate the toxic effects of BZ. The decrease in oxidative damage and inflammation observed in mice treated with AA+BZ10 could result in increased cardioprotection.

Correction: Flexibility evaluation of multiechelon supply chains.

[This corrects the article DOI: 10.1371/journal.pone.0194050.].

Flexibility evaluation of multiechelon supply chains.

Multiechelon supply chains are complex logistics systems that require flexibility and coordination at a tactical level to cope with environmental uncertainties in an efficient and effective manner. To cope with these challenges, mathematical programming models are developed to evaluate supply chain flexibility. However, under uncertainty, supply chain models become complex and the scope of flexibility analysis is generally reduced. This paper presents a unified approach that can evaluate the flexibility of a four-echelon supply chain via a robust stochastic programming model. The model simultaneously considers the plans of multiple business divisions such as marketing, logistics, manufacturing, and procurement, whose goals are often conflicting. A numerical example with deterministic parameters is presented to introduce the analysis, and then, the model stochastic parameters are considered to evaluate flexibility. The results of the analysis on supply, manufacturing, and distribution flexibility are presented. Tradeoff analysis of demand variability and service levels is also carried out. The proposed approach facilitates the adoption of different management styles, thus improving supply chain resilience. The model can be extended to contexts pertaining to supply chain disruptions; for example, the model can be used to explore operation strategies when subtle events disrupt supply, manufacturing, or distribution.