scholarly journals MXD6 in film manufacturing: State of the art and recent advances in the synthesis and characterization of new copolyamides

2019 ◽  
Vol 36 (1) ◽  
pp. 16-37
Author(s):  
Micaela Vannini ◽  
Paola Marchese ◽  
Annamaria Celli ◽  
Cesare Lorenzetti

Semiaromatic polyamides belong to a large family of polymers commonly utilized in demanding engineering applications due to a unique set of outstanding mechanical properties as well as in terms of thermal and chemical resistance. Somewhat less understood is the use of certain members of this family in packaging applications such as the manufacturing of films and sheets or thin-walled containers, as well as the motivations and limitations in designing film structures containing them. This article reviews how m-xylylene diamine (MXD)-based polyamides are used in packaging applications. Attention is also given to film manufacturing and criticalities in its processing. Recent developments in MXD-based polyamides for gas barrier applications are also reported, while examining future perspectives in speciality film manufacturing. The new described copolymers based on MXD6 were synthesized by introducing different co-units, like isophthalic acid, 2,6-naphthalenedicarboxylic acid, glutaric acid, oxalic acid or 1,6-hexamethylene diamine. The performed characterization analyses (DMTA, DSC, density and OTR) allowed the polymer structures and properties to be correlated. Introducing 2,6-naphthalenedicarboxylic acid along the MXD6 chain led to the highest Tg (101°C) and density (1.233 g/cm3) and the lowest OTR (0.0035 cm3·cm/m2·day·atm, up to one order of magnitude lower).

Pharmaceutics ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 542
Author(s):  
Maria Inês Teixeira ◽  
Maria Helena Amaral ◽  
Paulo C. Costa ◽  
Carla M. Lopes ◽  
Dimitrios A. Lamprou

Neurodegenerative diseases (NDs) bear a lot of weight in public health. By studying the properties of the blood-brain barrier (BBB) and its fundamental interactions with the central nervous system (CNS), it is possible to improve the understanding of the pathological mechanisms behind these disorders and create new and better strategies to improve bioavailability and therapeutic efficiency, such as nanocarriers. Microfluidics is an intersectional field with many applications. Microfluidic systems can be an invaluable tool to accurately simulate the BBB microenvironment, as well as develop, in a reproducible manner, drug delivery systems with well-defined physicochemical characteristics. This review provides an overview of the most recent advances on microfluidic devices for CNS-targeted studies. Firstly, the importance of the BBB will be addressed, and different experimental BBB models will be briefly discussed. Subsequently, microfluidic-integrated BBB models (BBB/brain-on-a-chip) are introduced and the state of the art reviewed, with special emphasis on their use to study NDs. Additionally, the microfluidic preparation of nanocarriers and other compounds for CNS delivery has been covered. The last section focuses on current challenges and future perspectives of microfluidic experimentation.


2019 ◽  
Vol 218 ◽  
pp. 72-100 ◽  
Author(s):  
Gino Groeneveld ◽  
Bob W. J. Pirok ◽  
Peter J. Schoenmakers

A practical example, the characterization of polysorbates by high-resolution comprehensive two-dimensional liquid chromatography in combination with high-resolution mass spectrometry, is described as a culmination of recent developments in 2D-LC and as an illustration of the current state of the art.


2012 ◽  
Vol 84 (2) ◽  
pp. 169-179 ◽  
Author(s):  
Rola Bou Khouzam ◽  
Joanna Szpunar ◽  
Michel Holeman ◽  
Ryszard Lobinski

Some elements in food are notoriously toxic, whereas others are considered essential for human health. Information on the exact chemical form in which an element is present in food is of paramount importance to determine the safety and nutritional quality of food. This critical review discusses the state of the art of analytical approaches to speciation of trace elements in food products. The topics addressed include (i) responding to regulations concerning some toxic elements (As, Hg, Sn); (ii) quality control of food and feed supplements; and (iii) characterization, in terms of element speciation, of nutritional plants (natural and genetically modified) and food supplements produced by biotechnology. The maturity of analytical techniques allowing the determination of individual well-defined metal species is highlighted. On the other hand, the recent developments of multidimensional hyphenated techniques and the democratization of electrospray high-resolution mass spectrometry (Orbitrap) start permitting fine characterization of element speciation in natural products.


2022 ◽  
Vol 1 ◽  
Author(s):  
Santiago Nahuel Chanquia ◽  
Alessia Valotta ◽  
Heidrun Gruber-Woelfler ◽  
Selin Kara

In the last years, there were two fields that experienced an astonishing growth within the biocatalysis community: photobiocatalysis and applications of flow technology to catalytic processes. Therefore, it is not a surprise that the combination of these two research areas also gave place to several recent interesting articles. However, to the best of our knowledge, no review article covering these advances was published so far. Within this review, we present recent and very recent developments in the field of photobiocatalysis in continuous flow, we discuss several different practical applications and features of state-of-the art photobioreactors and lastly, we present some future perspectives in the field.


Electronics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1375
Author(s):  
Bahare Mohamadzade ◽  
Roy B. V. B. Simorangkir ◽  
Sasa Maric ◽  
Ali Lalbakhsh ◽  
Karu P. Esselle ◽  
...  

Reconfigurable antennas have gained tremendous interest owing to their multifunctional capabilities while adhering to minimalistic space requirements in ever-shrinking electronics platforms and devices. A stark increase in demand for flexible and conformal antennas in modern and emerging unobtrusive and space-limited electronic systems has led to the development of the flexible and conformal reconfigurable antennas era. Flexible and conformal antennas rely on non-conventional materials and realization approaches, and thus, despite the mature knowledge available for rigid reconfigurable antennas, conventional reconfigurable techniques are not translated to a flexible domain in a straight forward manner. There are notable challenges associated with integration of reconfiguration elements such as switches, mechanical stability of the overall reconfigurable antenna, and the electronic robustness of the resulting devices when exposed to folding of sustained bending operations. This paper reviews various approaches demonstrated thus far, to realize flexible reconfigurable antennas, categorizing them on the basis of reconfiguration attributes, i.e., frequency, pattern, polarization, or a combination of these characteristics. The challenges associated with development and characterization of flexible and conformal reconfigurable antennas, the strengths and limitations of available methods are reviewed considering the progress in recent years, and open challenges for the future research are identified.


Author(s):  
Minu Mathew ◽  
Chandra Sekhar Rout

This review details the fundamentals, working principles and recent developments of Schottky junctions based on 2D materials to emphasize their improved gas sensing properties including low working temperature, high sensitivity, and selectivity.


2001 ◽  
Vol 66 (9) ◽  
pp. 1315-1340 ◽  
Author(s):  
Vladimir J. Balcar ◽  
Akiko Takamoto ◽  
Yukio Yoneda

The review highlights the landmark studies leading from the discovery and initial characterization of the Na+-dependent "high affinity" uptake in the mammalian brain to the cloning of individual transporters and the subsequent expansion of the field into the realm of molecular biology. When the data and hypotheses from 1970's are confronted with the recent developments in the field, we can conclude that the suggestions made nearly thirty years ago were essentially correct: the uptake, mediated by an active transport into neurons and glial cells, serves to control the extracellular concentrations of L-glutamate and prevents the neurotoxicity. The modern techniques of molecular biology may have provided additional data on the nature and location of the transporters but the classical neurochemical approach, using structural analogues of glutamate designed as specific inhibitors or substrates for glutamate transport, has been crucial for the investigations of particular roles that glutamate transport might play in health and disease. Analysis of recent structure/activity data presented in this review has yielded a novel insight into the pharmacological characteristics of L-glutamate transport, suggesting existence of additional heterogeneity in the system, beyond that so far discovered by molecular genetics. More compounds that specifically interact with individual glutamate transporters are urgently needed for more detailed investigations of neurochemical characteristics of glutamatergic transport and its integration into the glutamatergic synapses in the central nervous system. A review with 162 references.


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