Study of the Physical and Mechanical Properties of Thermoplastic Starch/Poly(Lactic Acid) Blends Modified with Acid Agents

In this work, we present a functionalization strategy of starch-poly(lactic acid) (PLA) blends with organic acids. Lactic and acetic acid were used as acid agents, and oleic acid was also included in the previous acids, with the aim of finding a synergy that thermodynamically benefits the products and provides hydrophobicity. The ratio of starch and sorbitol was 70:30, and the added acid agent replaced 6% of the plasticizer; meanwhile, the thermoplastic starch (TPS)–PLA blend proportion was 70:30 considering the modified TPS. The mixtures were obtained in a torque rheometer at 50 rpm for 10 min at 150 °C. The organic acids facilitated interactions between TPS and PLA. Although TPS and PLA are not miscible, PLA uniformly dispersed into the starch matrix. Furthermore, a reduction in the surface polarity was achieved, which enabled the wettability to reach values close to those of neat PLA (TPS–L-PLA increased by 55% compared to TPS–PLA). The rheological results showed a modulus similar to that of TPS. In general, there were transitions from elastic to viscous, in which the viscous phase predominated. The first and second-order thermal transitions did not show significant changes. The structural affinity of lactic acid with biopolymers (TPS–L-PLA) allowed a greater interaction and was corroborated with the mechanical properties, resulting in a greater resistance with respect to pure TPS and blended TPS–PLA (28.9%). These results are particularly relevant for the packaging industry.

Jurassic evolution and the structure of the central part of the Pieniny Klippen Belt (Carpathians) in Poland – new insight from the Czertezik Succession type area

The Czertezik Succession of the Pieniny Klippen Belt in Poland is assigned herein to its type area of occurrence – the main Pieniny Range, between Zamkowa Góra and Czertezik mounts. The reworked deposits of uppermost Pliensbachian, Toarcian and possibly Aalenian to lowermost Bajocian discovered in crinoidal limestones which indicate redeposition processes, especially during the Bajocian, are considered to be clearly important for reconstructing the depositional history. The redeposited Pliensbachian is represented by clasts of spotty limestones, the Toarcian by ferruginous grains and fragments of crusts/large oncoids of the ammonitico-rosso type (?Adnet Fm.), whereas the Aalenian and lowermost Bajocian is possibly represented by clasts of siliciclastic deposits and phosphatic nodules. This part of the succession resulted from the activity of rifting phases at the end of the Early Jurassic, and in the Bajocian, which caused the development of the special sedimentary environments typical of the Czertezik Succession. The younger Middle to Late Jurassic deposits represented by nodular limestones, radiolarites and micritic well-bedded limestones show a less distinct facies pattern, which is in part similar to that of other successions of the Pieniny Klippen Belt, although some rock-units such as the newly established Zamkowa Góra Bed, revealing the continuation of redeposition processes, remain specific to the Czertezik Succession. The Jurassic structure of the central part of the Pieniny Klippen Belt in Poland is revised due to the introduction of the Czertezik Ridge as a new palaeogeographic unit being the place of deposition of the Czertezik Succession. The revised position of the deposits shifts the structural affinity of the Czertezik Succession from the Subpieniny Nappe to the base of the Pieniny Nappe sensu Uhlig, 1907, and implies its closer palaeogeographic position to the Branisko–Pieniny successions than to the Czorsztyn–Niedzica successions as has been interpreted so far.

Philosophical Tenets of Action Research in Education

The juxtaposition of action and research conveys a sense of the richness and complexity of action research, yet it does not entirely translate its nuanced and sophisticated philosophy. In turn, an understanding of this philosophy is crucial for grasping action research’s radical originality. In this context at least, it may be more accurate to define action research by drawing on the term practice, even though it does not form part of the basic conceptual pair. Not only does practice make it easier for us to trace the constellation of philosophical influences behind the theory and practice of action research—from pragmatism to postmodernism, including Greek philosophy and Marxist and psychoanalytic schools of thought—but also to identify where these influences end and action research emerges as the bearer of a nontransferable view. Beyond this, at the heart of action research lies a structural affinity with singular social practices, which are its key ontological sites—that is, the context where action research in each case fills its epistemological and ethical dimensions with meaning. What kind of knowledge does action research aim to produce? What behaviors do action researchers engage in? Compared to other research paradigms in the social sciences—the field of education included—the specific quality of action research has to do with how its epistemological and ethical dimensions are shaped not from without but from within any given social practice. This is the key to its specific ecology. In action research, the epistemological and ethical realms do not stand beyond or above the situated social practices, with their values, principles of procedure, knowledges, and discourses, including their own literacies and modalities—in short, their own internal cultures. Action research conceives and presents itself as a rational and systematic way for members of the different social practices to build and rebuild their own epistemologies and ethics precisely by drawing on, and selecting from, their own internal cultures. How does this ecological perspective translate itself in education? Education is one of the key areas in which action research is generally applied, together with welfare and healthcare. Yet apart from the specific use of action research by educators, action research carries within itself a specific educational philosophy (and a political philosophy as well) which underlies its application, regardless of the specific social practice in which it takes place. In the same way that action research is politically democratic, educationally speaking action research is participatory, meaning that learning, improvement, or development can only be realized through a self-determining process in which people act and research freely upon and among themselves. This is precisely what action research facilitates in the different social practices. Action research is always educational, whether one develops it in education, welfare, or healthcare. As a result, action research has contributed a clear-cut pedagogical model that some critical educators have already imported to their own educational institutions and practices: youth participatory action research.

Confusing cases: Forrester, Stoller, Agnes, woman

This article pursues the hypothesis that there is a structural affinity between the case study as a genre of writing and the question of gendered subjectivity. With John Forrester’s chapter ‘Inventing Gender Identity: The Case of Agnes’ as my starting point, I ask how the case of ‘Agnes’ continues to inform our understanding of different disciplinary approaches (sociological and psychoanalytic) to theorizing gender. I establish a conversation between distinct, psychoanalytically informed feminisms (Simone de Beauvoir, Juliet Mitchell, Judith Butler, and Denise Riley) to move from the mid-20th century to contemporary cultural debate.

Import pathways of the mannityl-opines into the bacterial pathogen Agrobacterium tumefaciens: structural, affinity and in vivo approaches

Agrobacterium tumefaciens pathogens use specific compounds denoted opines as nutrients in their plant tumor niche. These opines are produced by the host plant cells genetically modified by agrobacteria. They are imported into bacteria via solute-binding proteins (SBPs) in association with ATP-binding cassette transporters. The mannityl-opine family encompasses mannopine, mannopinic acid, agropine and agropinic acid. Structural and affinity data on mannopinic acid bound to SBPs are currently lacking while those of the three others mannityl opines are available. We investigated the molecular basis of two pathways for mannopinic acid uptake. MoaA was proposed as the specific SBP for mannopinic acid import in mannityl opines-assimilating agrobacteria, which was validated here using genetic studies and affinity measurements. We structurally characterized the mannopinic acid-binding mode of MoaA in two crystal forms at 2.05 and 1.57 Å resolution. We demonstrated that the non-specific SBP MotA, so far characterized as mannopine and Amadori compound importer, was also able to transport mannopinic acid. The structure of MotA bound to mannopinic acid at 2.2 Å resolution defines a different mannopinic acid-binding signature, similar to that of mannopine. Combining in vitro and in vivo approaches, this work allowed us to complete the characterization of the mannityl-opines assimilation pathways, highlighting the important role of two dual imports of agropinic and mannopinic acids. Our data shed new light on how the mannityl-opines contribute to the establishment of the ecological niche of agrobacteria from the early to the late stages of tumor development.

Apatite from NWA 10153 and NWA 10645—The Key to Deciphering Magmatic and Fluid Evolution History in Nakhlites

Apatites from Martian nakhlites NWA 10153 and NWA 10645 were used to obtain insight into their crystallization environment and the subsequent postcrystallization evolution path. The research results acquired using multi-tool analyses show distinctive transformation processes that were not fully completed. The crystallization history of three apatite generations (OH-bearing, Cl-rich fluorapatite as well as OH-poor, F-rich chlorapatite and fluorapatite) were reconstructed using transmission electron microscopy and geochemical analyses. Magmatic OH-bearing, Cl-rich fluorapatite changed its primary composition and evolved toward OH-poor, F-rich chlorapatite because of its interaction with fluids. Degassing of restitic magma causes fluorapatite crystallization, which shows a strong structural affinity for the last episode of system evolution. In addition to the three apatite generations, a fourth amorphous phase of calcium phosphate has been identified with Raman spectroscopy. This amorphous phase may be considered a transition phase between magmatic and hydrothermal phases. It may give insight into the dissolution process of magmatic phosphates, help in processing reconstruction, and allow to decipher mineral interactions with hydrothermal fluids.