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In pulp and paper mills, effective biosludge dewatering is essential in wastewater treatment to reduce the large volume of biosludge that needs to be treated and disposed. The dewatering process normally requires the use of polymers from petroleum‐based sources. This study explores the potential of using cationic proteins such as protamine for biosludge dewatering through dual conditioning with a small amount of a synthetic anionic polymer such as anionic polyacrylamide (APAM). The results show that dual conditioning provides substantial synergistic enhancements in dewatering. The maximum cake solids content of biosludge achieved by adding protamine (7.5%) alone was 12%. By dual conditioning with a small amount of APAM (0.1%), not only the cake solids content was increased to 16%, but also the amount of protamine addition was substantially lowered to 2%. These results, coupled with the change in zeta potential of the particles in the biosludge samples, suggest that the cationic protamine reduced the negative charge of the particles, allowing smaller particles to agglomerate and providing a positively charged framework for the subsequent addition of the negatively charged APAM. After adding APAM, substantial floc‐bridging occurred, allowing smaller flocs to aggregate into larger flocs. These synergistic effects can lower the wastewater treatment cost by reducing the amount of synthetic polymer and by applying low‐value proteins from natural sources. [ABSTRACT FROM AUTHOR]

The article reports on the "liquid wood" bioplastic that was created by German scientists at the Fraunhofer Institute and the spin-out company TECNARO using lignin waste from paper production. The bioplastic so high quality it can be used to make toys. The researchers mixed the bioplastic with natural resins and waxes in order to produce a low-sulphur, insoluble plastic from 100% renewable sources. Finished products can be reprocessed ten times without a noticeable change in the quality of the plastic.

Acidic capsular polysaccharide of Vibrio parahaemolyticus A55 (05:K15) was esterified with ethylene oxide and then reduced with sodium borohydride. Hydrolysis of the reduced material gave two hexosamines identical with mannosamine (2-amino-2-deoxy-mannose) and gulosamine (2-amino.2-deoxy-gulose) on paper and ion-exchange chromatograms. This fact suggested that the K15 antigen contained mannosaminuronic acid (2-amino-2-deoxy-mannuronic acid) and gulosaminuronic acid (2-amino-2-deoxy-guluronie acid). Direct acid hydrolysis of the antigen gave two 2-amino-2-deoxy-hexuronic acids. These two were identified as mannosaminuronic and gulosaminouronic acids by paper chromatography and paper electrophoresis, being compared with synthesized standard samples. Titration of acid form of the polysaccharide indicated that about 91.5% of the polysaccharide was composed of the N-acetyl-hexosaminuronic acids. [ABSTRACT FROM AUTHOR]

In this paper, a guar gum‐based hydraulic fracturing fluid suitable for low permeability oil and gas reservoirs was prepared using alkylamine guar gum (J580) as a thickening agent. The viscosification mechanism and comprehensive properties were analyzed to provide theoretical support for improving the fracturing fluid utilization rate and oil and gas field development in Changqing Oilfield. In this experiment, the properties and microstructure of thickener J580 were analyzed by infrared spectroscopy (FT‐IR), nuclear magnetic resonance (1H‐NMR), X‐ray diffraction (XRD), and transmission electron microscope (TEM). The rheometer, dynamic filtration device, and acid erosion fracture conductive ability device were used to study the temperature and shear resistance performance, viscoelastic properties, dynamic filtration performance, and fracture conductive ability damage of the system. the gel breaking performance, formation water compatibility, and anti‐swelling performance of the system were measured according to the standard. The results show that J580 is an amine modified product of guar gum, and its viscosity increasing mechanism is similar to that of guar gum. The breaking time of the system is 375 s, the residue content is 413 mg/L, and the surface tension is 26.49 mN/m. At 90°C, the viscosity of the solution can be maintained at 180 mPa · s, loss modulus G" dominates, the anti‐swelling rate is 82.5%, the damage rate of the conductive ability is 22.40%, and the dynamic filtration coefficient is 1.3 × 10−5 m/s1/2. The fracturing fluid system has good dynamic filtration performance, conductive ability, temperature and shear resistance, good structural strength, can easily break glue and return, and less residue content. [ABSTRACT FROM AUTHOR]

The food industry is adapting to evolving consumer demands for "healthy" and premium quality food by reducing the adverse effects of food packaging through innovative advancements in active and intelligent packaging technologies. These smart innovations offer diverse and creative ways to enhance food product quality and safety while extending shelf life. Emerging techniques are also improving the passive aspects of food packaging systems, such as thermal stability, barrier effectiveness, and mechanical strength. Notably, the use of plants, biodegradable materials, and nanomaterials in sustainable food packaging helps mitigate its negative environmental impact. By integrating intelligent, environmentally friendly, and active packaging technologies, a multipurpose food packaging system can be developed that maintains the integrity of all its components, representing the pinnacle of technological advancement in food packaging. This article reviews the fundamentals of food packaging systems, recent advancements in various packaging techniques, commercialized patents, future research trends, and the challenges that need to be addressed in food packaging. [ABSTRACT FROM AUTHOR]

Peptide nucleic acids (PNAs) are neutral mimics of natural DNA and RNA biopolymers that have caught the attention of researchers working on the identification of specific sequences of nucleobases in DNA/RNA strands. For this purpose, specific analytical protocols need to be developed to optimize the nucleic acid recognition ability of PNAs, exploiting both the high intrinsic affinity of PNA/DNA(RNA) couples as well as suitable markers, either linked to the PNA backbone or properly interacting with it in the working medium. In this context, the paper reports on phthalimide and 4‐nitrophthalimide as two cheap, metal‐free electroactive markers covalently bound to the pseudo‐peptide backbone of a PNA decamer. After a preliminary characterization of the markers, as such and in PNA conjugates, attention has been moved toward the optimization of the detectability of the labeled PNA decamers in aqueous solutions. Exploiting the potentiometric stripping analysis on hanging mercury drop electrode it has been possible to reach satisfactory detection limits of ca. 10 nM avoiding the use of expensive transition metal complexes as labels and/or of co‐reagents. [ABSTRACT FROM AUTHOR]

Production of biopolymer for packaging applications is still a burgeoning demand with the rising environmental concern about pollution due to non‐degradable plastic waste materials. This paper introduces a novel approach, yet a continuous production method, to produce PLA multilayer film/foams structures having 16, 32, and 64 alternating layers which were developed by multilayer coextrusion technique, and the morphology, density, mechanical properties and oxygen transmission of the as‐extruded film/foams were characterized. The lightweight multilayered PLA film/foam has a unique solid/porous alternating horizontal architecture, in which the film layers can effectively control the growth of the cells and suppress the premature rupture of cells during coextrusion process. Tensile properties at elevated temperatures of the PLA film/foam were used to optimize thermoforming conditions. The effects of annealing temperature and time on the crystallinity and oxygen permeability of PLA multilayer film/foams were investigated. Oxygen transmission showed a strong correlation with the crystallinity of PLA multilayer film/foam. The material with 32 layers 50/50 film/foam achieved extremely high barrier after 30 min annealing, which is 35 times better than the control. [ABSTRACT FROM AUTHOR]

The application of collagen‐based hydrogel is severely restricted due to its poor mechanical strength and functional singleness. In this paper, two‐dimensional MXene nanosheets were introduced into collagen/acrylic acid (AA) system, which was polymerized in situ to produce versatile hydrogel (GCol‐MX‐PAA). The tensile stress and compressive stress values of the resultant hydrogel at the MXene concentration of 5 mg/mL reached 211.5 kPa and 7.8 MPa, respectively, which were approximately 4.0 and 1.4 times higher than those of GCol‐PAA. The bonding strength of the hydrogel reached 30.7 kPa in the porcine skin‐adhesive model owing to the large number of free phenolic hydroxyl groups on GCol. Furthermore, GCol‐MX‐PAA could be applied to monitor large and subtle activities of human body due to the excellent electrical conductivity of MXene. Thanks to the outstanding photothermal conversion performance of MXene, the hydrogel could kill E. coli and S. aureus effectively under NIR irradiation. In addition, in vitro cytotoxicity test performed on L929 fibroblasts demonstrated the desirable biocompatibility of GCol‐MX‐PAA. The design strategy in this work gives guidance for the development of multifunctional collagen‐based hydrogel in a wide range of applications. Highlights: Versatile hydrogel constructed from GA‐modified collagen, PAA, and MXene.The composite hydrogel displays improved mechanical properties.This hydrogel possesses superior tissue adhesion and strain sensitivity.This hydrogel shows desired photothermal antibacterial property and biocompatibility. [ABSTRACT FROM AUTHOR]

A surgical procedure for the repair of damaged periodontal tissue is Guided Tissue Regeneration (GTR), which involves the use of a barrier membrane to prevent soft tissue ingrowth and create a space for slow regeneration of periodontium and bone. GTR membrane should have pores able to facilitate the diffusion of fluids, oxygen, nutrients, and bioactive substances for cell growth, but also be impermeable to epithelial cells or gingival fibroblasts, which could overpopulate the defect space and inhibit infiltration and activity of bone‐forming cells. In this paper, a bilayer PLGA membrane was realized by coupling the dip coating and electrospinning techniques. The rough layer of the double‐sided structure was electrospun on the previously prepared smooth dip‐coated membrane. A rotating drum collector at two rotating speeds was used to generate different fibers orientation. The bilayer membrane with different superimposed surfaces was successfully fabricated and characterized from a morphological, physicochemical, and the mechanical point of view. Performed analyses revealed that the membrane possesses suitable properties, especially from mechanical point of view, for its possible use as a scaffold for the GTR of periodontum. A high fiber alignment and improved mechanical properties with respect to available GTR membranes characterized the product resulting from this study. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the wear resistance of ultrahigh‐molecular weight polyethylene (UHMWPE) and crosslinked polyethylene (XLPE) against different counterfaces. Friction and wear studies were evaluated under dry reciprocating sliding conditions at room temperature. Ti6Al4V discs finished in polished, lapped, and ground conditions were reciprocated against polymer cylinders. In addition, abrasive wear studies were conducted using different abrasive grit sizes. The friction and wear properties of the two polyethylenes were strongly affected by the different counterfaces. XLPE showed important friction and wear sensitivity with the change of surface roughness of the Ti6Al4V disc, as well as with the change in abrasive grit size. Scanning electron microscopy and energy‐dispersive X‐ray (EDX) analysis of the worn disc surfaces and the polymer pins indicated the wear mechanisms affecting the polyethylenes. POLYM. ENG. SCI., 59:2356–2366, 2019. © 2019 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

The separator is an essential component of sodium‐ion batteries (SIBs) to determine their electrochemical performances. However, the separator with high mechanical strength, good electrolyte wettability and excellent electrochemical performance remains an open challenge. Herein, a new separator consisting of amphoteric nanofibers with abundant functional groups was fabricated through supramolecular assembly of natural polymers for SIB. The uniform nanoporous structure, remarkable mechanical properties and abundant functional groups (e.g. −COOH, −NH2 and −OH) endow the separator with lower dissolution activation energy and higher ion migration numbers. These metrics enable the separator to lower the barrier for desolvation of Na+, accelerate the migration of Na+, and generate more stable solid electrolyte interphase (SEI) and cathode electrolyte interphase (CEI). The battery assembled with the amphoteric nanofiber separator shows higher specific capacity and better stability than that assembled with glass fiber (GF) separator. [ABSTRACT FROM AUTHOR]

From the lipopolysaccharides of Vibrio cholerae strains Inaba and Ogawa, an unusual amino sugar was isolated. By sequential oxidation with sodium metaperiodate and hypoiodide and by oxidation with periodate followed by detection of the acetaldehyde formed, the amino sugar was characterized as a 2-amino-dideoxyaldose. The hydroehloride of the amino sugar was compared with those of 2-amino-2,6-dideoxy-D-glucose, 2-amino-2,6-dideoxy-L-galactose, 2-amino-2,6-dideoxy-D-mannose, 2-amino-2,6.di-deoxy-D-gulose, and 2-amino-2,6-dideoxy-D-allose in an amino acid analyzer. The amino sugar alcohols were studied by paper electrophoresis in molybdats buffer. From the results obtained the amino sugar was identified as 2.amino-2,6-dideoxyglucose (quinovosamine). Its optical rotation indicated it to be of the D-configuration. [ABSTRACT FROM AUTHOR]

Non‐melanoma skin cancers (NMSC) represent the most common skin tumours of the head region. We describe the use of dermal substitute in a 2‐stage surgery protocol for selected fragile patients to remove NMSC of the head region. A review of the literature focusing on dermal substitutes’ safety after skin tumours excision is provided. A total of 45 fragile patients with NMSC in the head region were selected and scheduled for the 2‐stage surgical protocol. The first stage consisted of traditional surgical excision and immediate coverage with Hyalomatrix (Fidia Advanced Biopolymers, Abano Terme, Italy). After histology confirmed diagnosis and clearance of the margins, full‐thickness skin autografts were performed. All of the patients reached complete tumour excision and wound healing. No local recurrences were registered during 24 months follow up. The 2‐stage surgical therapeutic‐diagnostic‐reconstructive approach represents a less stressful and oncologically safe surgical protocol in selected fragile patients. When patients cannot tolerate invasive and long surgical procedures, general anaesthesia, and long hospitalisation, skin grafting following temporary skin substitute coverage can achieve oncological clearance and provide good functional and aesthetic results. The use of dermal substitutes represents a valid alternative surgical option in cases of ASA III, fragile patients non‐eligible for complex reconstructive surgery. To our knowledge, this is the first paper reviewing literature focusing on dermal substitutes’ applications and safety after skin tumour excision. [ABSTRACT FROM AUTHOR]

As part of ongoing efforts to discover novel polyhydroxyalkanoate‐producing bacterial species, we embarked on characterizing the thermotolerant species, Paracoccus kondratievae, for biopolymer synthesis. Using traditional chemical and thermal characterization techniques, we found that P. kondratievae accumulates poly(3‐hydroxybutyrate) (PHB), reaching up to 46.8% of the cell's dry weight after a 24‐h incubation at 42°C. Although P. kondratievae is phylogenetically related to the prototypical polyhydroxyalkanoate producer, Paracoccus denitrificans, we observed significant differences in the PHB production dynamics between these two Paracoccus species. Notably, P. kondratievae can grow and produce PHB at elevated temperatures ranging from 42 to 47°C. Furthermore, P. kondratievae reaches its peak PHB content during the early stationary growth phase, specifically after 24 h of growth in a flask culture. This is then followed by a decline in the later stages of the stationary growth phase. The depolymerization observed in this growth phase is facilitated by the abundant presence of the PhaZ depolymerase enzyme associated with PHB granules. We observed the highest PHB levels when the cells were cultivated in a medium with glycerol as the sole carbon source and a carbon‐to‐nitrogen ratio of 10. Finally, we found that PHB production is induced as an osmotic stress response, similar to other polyhydroxyalkanoate‐producing species. [ABSTRACT FROM AUTHOR]

Nafion has been dominating the proton exchange membrane (PEM) market because of its adequacy for the proton exchange operation. However, because of its high cost, low performance at low relative humidity, and finally environmental unfriendliness, researchers have been developing and working on Nafion alternatives. In this review, we assess how biopolymers present an opportunity as an eco‐friendly material able to replace the conventional Nafion membrane in proton exchange membrane fuel cells (PEMFC). Chitosan and cellulose were the most studied in literature owing to their abundance in nature, low cost, and high affinity for water, which are sought‐after properties for PEM. In addition to that, their ease of modification through their hydroxyl or amine groups represents an opportunity to further enhance their characteristics and thus meet the criteria of diverse applications. The use of biopolymers as an adequate PEM is facing many challenges. Having a practical proton conductivity and securing the physicochemical stability of the biopolymers in fuel cell operating conditions are two of the most important challenges to overcome. Promising strategies to simultaneously address these challenges such as crosslinking, making interpenetrated networks, and making blends and composites are reported. [ABSTRACT FROM AUTHOR]

Mild acid degradation of lipopolysaccharides from Pseudomonas aeruginosa O10a and O10a,b (Lányi classification) resulted in O-specific polysaccharides built up of trisaccharide repeating units containing 2-acetamido-2,6-dideoxy-D-glucose (N-acetylquinovosamine, DQuiNAc), 2-acetamido-2,6-dideoxy-D-galactose (N-acetylfucosamine, DFucNAc), and 5-acetamido-3,5,7,9-tetradeoxy-7-[(R)-3-hydroxybutyramido]-L-glycero-L-mannononulosonic acid. The latter is a di-N-acyl derivative of a new sialic-acid-like sugar which was called by us pseudaminic acid (PseN2). A 3-hydroxybutyric acid residue was also found in natural carbohydrates for the first time. In the O10a,b polysaccharide pseudaminic acid carried an O-acetyl group at position 4. For selective cleavage of the O10a polysaccharide, solvolysis with hydrogen fluoride was employed which, owing to the relatively high stability of the glycosidic linkage of pseudaminic acid, led to the disaccharide with this sugar on the non-reducing terminus. Performing the solvolysis in methanol afforded the methyl glycoside of this disaccharide which proved to be more advantageous for further analysis. Carboxyl-reduction made the glycosidic linkage of pseudaminic acid extremely labile, and mild acid hydrolysis of the carboxyl-reduced O10a polysaccharide afforded the trisaccharide with a ketose derivative on the reducing terminus. Establishing the structure of the oligosaccharide fragments obtained and interpreting the 13C nuclear resonance spectra of the polysaccharides allowed to determine the following structure for their repeating units: → 4)DFucNAc(α1 → 3)DQuiNAc(β1 → OCHCH2CO → 7)PseN2Ac(β2 I 41 (R) CH3 OR serotype O10a R = H serotype O10a,b R = Ac In the polysaccharides the N-acetylquinovosamine residue is attached not to pseudaminic acid itself, but to its N-acyl substituent, 3-hydroxybutyryl group, and thus the monomers are linked via both glycosidic and amidic linkages. [ABSTRACT FROM AUTHOR]

Two lipopolysaccharide preparations were obtained from Escherichia coli 058 by extraction with 45% aqueous phenol and fractional precipitation with cetyltrimethyl ammonium bromide (Cetavlon). Chemical analysis and polyacrylamide gel electrophoresis in the presence of sodium dodecylsulfate showed that the two preparations differed only in the extent of the O-specific polysaccharide moiety. The O-specific polysaccharide was characterized with proton magnetic resonance and infrared spectroscopy, optical rotation and paper electrophoresis. Using gas-liquid chromatography and ion-exchange chromatography, it was shown to contain D-mannose, 2-acetamido-2-deoxy-D-glucose, 3-O-(R-1'-carboxyethyl)-L-rhamnose (rhamnolactylic acid), and O-acetyl groups in the molar ratios of 2:1:1:1. The polysaccharide and oligosaccharides obtained from it were subjected to methylation and chromic acid oxidation. The results obtained indicated that the polysaccharide consists of tetrasaccharide repeating units in which the trisaccharide β-GlcNAc1-4αMan-1-4(2/3-O-Ac)-Man is substituted at C-3 of the non-acetylated mannose with rhamnolactylic acid. The repeating units are joined through α-mannosyl-1-3-glucosamine bonds. This structure is identical with that of the cell wall polysaccharide of Shigella dysenteriae type 5. [ABSTRACT FROM AUTHOR]

A linear lattice of equivalent binding sites with nearest neighbor cooperativity is used as a basic model for a linear biopolymer displaying cooperative binding of small ligands. Complicating effects due to the dimerization of free ligands are taken into account. The theory implies two types of intrinsic binding processes: (1) the binding of an isolated ligand (nucleation), and (2) the binding of a ligand in the immediate neighborhood of an already bound one (aggregation). The ratio of the respective association constants determines the degree of cooperativity. It is generally shown how the equilibrium properties of the system can be derived by means of the matrix method. Sonic properties of special practical significance, such as the equilibrium concentrations of free and bound monomer ligands, are discussed in more detail. On the basis of a pertinent kinetic model chemical relaxation of strong cooperative bindinng is also examined. The paper gives particular emphasis to the formulation of quantitative relations which are most useful for an experimental application of the the oretical results. Appropriate procedures to plot measurable data and to evaluate basic parameters are proposed. They are applied to specific experimental systems in a subsequent set of papers. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) are effective solvents for biomass. Refined cellulose is commonly used; however, recent interest has grown to consider woody and herbaceous biomass and industrial crop residues like fruit peels. Here, the authors report results on the dissolution and shaping of cotton and coffee fruit (cascara) in 1,8‐diazabicyclo[5.4.0]undec‐7‐inium acetate ([DBUH][OAc]). Cascara is a high‐volume, low‐value crop residue that poses an environmental and economic burden in producer countries leading to a high‐value proposition if recoverable. Fruit/ionic liquid solutions (0–15% w/w dissolved at 60 °C) were characterized with respect to biomass concentration and shaped into fibers and films coagulated in DI water and methanol. Rheology was assessed using parallel plate rheometry. Cotton/IL mixtures formed better fibers compared to cascara‐based solutions, which required 2.6× more biomass in solution for viable fiber formation. At 10% loading, fibers could be produced from untreated coffee fruit with diameters ranging from 18–100 microns. Coffee fruit residues and their precipitated films show that both cellulose and lignin dissolve in pure [DBUH][OAc]. Chemical characterization of cascara and cascara films demonstrates the conveyance of high concentrations of lignin and extracts that result in weaker mechanical properties. Further purification of cascara is required for effective use in structural applications. [ABSTRACT FROM AUTHOR]

Green and scalable materials are essential to fulfill the need of electrification for transitioning into a fossil‐fuels free society, and sustainability is a requirement for all new technologies. Rechargeable batteries are one of the most important elements for electrification, enabling the transition to mobile electronics, electrical vehicles and grid storage. We here report synthesis and characterization of polyelectrolyte complexes of alginate and chitosan, both biopolymers deriving from the sea, for transport of zinc ions in hydrogel electrolytes. We have used vibrational spectroscopy, thermal measurements and microscopy, as well as transport measurements with ohmic or blocking contacts. The transference number for zinc ions is close to 1, the conductivity is ≈10 mS/cm, with stability at Zn interfaces seen through 7000 cycles in symmetric zinc//zinc cell. [ABSTRACT FROM AUTHOR]

Food packaging is used worldwide and is a common technique for protecting food safety and quality while increasing shelf life. Environmental issues caused by using polymers in packaging derived from petroleum are becoming more significant and more well‐known. Interest in ecofriendly packaging materials made of renewable resources (biopolymers) has steadily increased, particularly for temporary and throw‐away packaging applications. However, biopolymers frequently have poor processability, poor mechanical, and poor barrier characteristics, restricting their industrial application and scalable manufacturing. Researchers have created bionanocomposites with improved packaging qualities like antibacterial function, mechanical toughness, optical clarity, and gas and water barrier properties to overcome these restrictions. This review seeks to inform readers about recent advances in active food packaging that use biopolymers and bionanocomposite materials. The difficulties and possibilities presented by such resources for the food packaging sector have been examined. This review is timely given the recent spike in interest in research projects both in academia and industry seeking to create a new group of materials for packaging based on biopolymer for food with potential uses elsewhere. [ABSTRACT FROM AUTHOR]

The necessity to continuously and seamlessly monitor human health is calling for compliant, comfortable, and safe wearables. The employment of piezoelectric biopolymers in form of thin film perfectly matches with these needs due to their inherent flexibility, sensitivity, and biocompatibility. Among them, chitosan is a low cost, highly sustainable, and biocompatible material with a great potential for applications in compliant wearables. However, chitosan and biopolymers in general show relatively low piezoelectric coefficients and processing difficulties. Here, it is shown a facile approach to increase more than twice the piezoelectric coefficient of thin chitosan film and to process this promising biomaterial for the fabrication of the first set of thin chitosan film‐based ultrasound transducers. This work leverages the exploitation of environmental‐friendly biopolymers in the development of compliant wearable transducers and thus represents a step forward in the development of completely biodegradable, transparent, thin, and flexible piezoelectric macro‐ and microtransducers. [ABSTRACT FROM AUTHOR]

Fly ash (FA), a by‐product of the power generation industry, can potentially be used as a filler in polymer products. Particularly, FA has been investigated as an alternative filler to partially or fully replace commercial fillers in polymer composites. This mini‐review discusses the fundamental properties of FA, environmental pollution from commercial fillers, and the performance of FA in polymers. The properties of FA‐loaded polymer composites are discussed, including the morphological, rheological, mechanical, and thermal properties. This review highlights the potential methods and challenges for substituting, or replacing, commercial fillers in various polymers such as natural rubber (NR), epoxidized NR, epoxy, styrene‐butadiene rubber (SBR), NR/SBR blends, polyethylene, polypropylene, and polyester. [ABSTRACT FROM AUTHOR]

Moving toward high‐throughput production of biopolymer aerogel microparticles, in this work, the wet milling process is applied to hydrogels and alcogels. Alcogels are then converted into aerogels by well‐established supercritical drying. Alginate and hybrid alginate/silica gels are used as a model system. As the Young's moduli of hydrogels significantly change when water is exchanged by ethanol, it is possible to study the effect of the gel stiffness on macroscopic and microstructural properties of the resulting aerogels. Influence of process parameters (milling speed and gap size) is also investigated. Smallest particles sizes and minimal changes in microstructure are obtained for completely solvent exchanged gels. The wet milling is shown to be a versatile method to obtain aerogel particles with diameters in the range 50–300 µm. [ABSTRACT FROM AUTHOR]

Aerial robots can autonomously collect temporal and spatial high‐resolution environmental data. This data can be utilized to develop mathematical ecology models to understand the impact of climate change on the habitat. In case of drone malfunction, the incorporated materials can threaten vulnerable environments. The recent introduction of transient robotics enables the development of biodegradable, environmental‐sensing drones capable of degrading in their environment. However, manufacturing methods for environmental‐sensing transient drones are rarely discussed. Herein, a manufacturing framework and material selection process featuring biopolymer‐based, high‐strength composite cryogels, and printed carbon‐based electronics for transient drones are highlighted. It is found that gelatin‐ and cellulose‐based cryogels mechanically outperform other biopolymer composites while having a homogeneous microstructure and high stiffness‐to‐weight ratio. The selected materials are used to manufacture a flying‐wing air‐frame, while the incorporated sensing skin is capable of measuring the elevons' deflection angles as well as ambient temperature. It is demonstrated in the results how gelatin–cellulose cryogels can be used to manufacture lightweight transient drones, while printing carbon‐conductive electronics is a viable method for designing sustainable, integrated sensors. The proposed methods can be used to guide the development of lightweight and rapidly degrading robots, featuring eco‐friendly sensing capabilities. An interactive preprint version of the article can be found here: https://doi.org/10.22541/au.167506513.33779420/v1. [ABSTRACT FROM AUTHOR]

Proton-nuclear-magnetic-resonance spectroscopy is a powerful tool for investigating the solution structure of biopolymers provided that a substantial number of proton resonances are assigned in the spectrum. For large proteins the assignments have usually been made by the comparative one-dimensional NMR investigations of the parent and derivative proteins in different physicochemical conditions. In this paper, we show that the more powerful two-dimensional methods could be successfully applide to proteins of the size of human adult hemoglobin (Mr = 64 500). J-Correlated and NOE-correlated spectroscopy, together with topological relationships in the known crystalline structure, enabled us to assign a large number of resonances. The majority of the assigned resonances correspond to the heine substituents and to amino acids in the heme pockets of the two subunits. These results thus provide an extensive set of intrinsic probes for mapping the conformation of the ligand-binding site and its functional changes. Comparison of the observed ring-current shifts of the assigned resonances with those calculated from the known crystallographic coordinates suggests a close similarity between the heme-pocket tertiary conformation in solution and in the crystalline state. A significant difference was noted for Leu141 in β subunits which, in solution, appears to have stronger contacts with the heine groups than in the crystalline form. The present results also demonstrate that two-dimensional-NMR methods could be successfully applied to the investigation of the structure of large biomolecules in solution (Mr ≤ 65 000). [ABSTRACT FROM AUTHOR]

The primary structure of Klebsiella serotype K10 capsular polysaccharide has been investigated using mainly the techniques of methylation, partial hydrolysis, and 1H and 13C NMR spectroscopy. The polysaccharide was found to consist of hexasaccharide repeating units having the following structure: [This symbol cannot be presented in ASCII format] [ABSTRACT FROM AUTHOR]

The expression of a diverse array of receptors for sulphated polysaccharides on lymphocytes has been demonstrated by Parish & Snowden (1985). This paper presents evidence to suggest that other cell types, namely macrophages, polymorphonuclear leucocytes, mast cells and fibroblasts, can bind similar polysaccharides. Using a rosetting assay and eleven structurally unique polysaccharides, each cell type was observed to bind a characteristic array of these polysaccharides. Analysis of the polysaccharide reactivity of macrophages revealed that BCG-activated and thioglycollate-elicited macrophages express an expanded repertoire of reactivity compared to resident peritoneal macrophages. For example, only thioglycollate-elicited macrophages, but not resident and BCG-activated peritoneal macrophages, reacted with the glycosaminoglycans, chondroitin-4-sulphate, chondroitin-6-sulphate and dermatan sulphate, while both BCG- and thioglycolate-activated, but not resident peritoneal macrophages, bound pentosan polysulphate-coupled sheep erythrocytes. The expression of the receptors for chondroitin-4- and -6-sulphate was observed to be cyclic and peaked at 2 and 5-6 days after thioglycollate treatment. Preliminary analyses of the functional significance of the observed binding of polysaccharides to macrophages revealed that heparin, fucoidan and kappa-carrageenen were specifically endocytosed. However, endocytosis of all other test polysaccharides was not observed. Finally, polysaccharide-coupled sheep erythrocytes were not phagocytosed, even though they interacted strongly with the macrophage surface. The possible relevance of these observations to an inflammatory response and as a means of identifying cellular subsets is discussed. [ABSTRACT FROM AUTHOR]

Westphal's procedure was found the most suitable for the isolation of lipopolysaccharide fractions from Brucella melitensis cells; only the fraction obtained in the aqueous layer (LPS) is studied in this paper. Beside LPS, an extracellular polysaccharide fraction (PS) was extracted from the culture medium of the bacteria, and the chemical composition of both fractions, LPS and PS, has been compared. In both cases, nucleic acid contaminants were eliminated either by alcohol precipitation or by use of cetavlon. These treatments also removed an acidic polysaccharide containing mainly galactosaminuronic acid, which might be Vi antigen. The main difference between LPS and PS is the presence of a small amount of lipid A in LPS (ca. 1%). As in the case of lipid A isolated from LPS of Enterobacteria, Brucella lipid A contains glucosamine and fatty acids, but β-hydroxymyristic acid could not be detected. The behaviour of LPS and PS fractions on DEAE-cellulose columns is very similar, and the small differences that could be observed may be explained by solubility changes due to the lipid moiety present in LPS. Both fractions contain 2-keto-3-hydroxy-octulosonic acid, a mixture of D- and L-glyceroD-mannoheptoses, a high amount of glucose, galactose, a 3,6-dideoxyhexose (colitose or abequose), and a methylated sugar behaving as a methylated derivative of dideoxyhexose. Small amounts of rhamnose in PS and of arabinose in LPS seem to be due to contaminants. [ABSTRACT FROM AUTHOR]

Bioactive glasses are widely utilized to regenerate bone tissue and aid bonding of orthopedic implants. Forming composites of bioglass with bioactive polymers allow the mechanical properties and biological response to be tailored. Although several methods for creating bioglass–polymer composites exist, they require dissolution of the polymer, controlled phase separation, and appear to have an upper limit of ∼30 vol.% bioglass. Cold sintering is a novel technique for the densification of ceramics and glasses which utilizes a liquid phase and pressure to allow the production of components at reduced temperatures. We demonstrate that cold sintering (100°C) of Bioglass 45S5 powder produced via flame spray pyrolysis and the fabrication of Bioglass 45S5–polymer composites. Assessment of the in vitro response revealed that composites were not cytotoxic. Solid‐state 31P and 29Si MAS NMR studies of the silicon and phosphorus speciation in the glass powder, as‐received, wetted, and sintered samples show similarities to reactions expected when bioglass is implanted in the body which along with Raman spectroscopy data gave insight into the cold sintering densification mechanism. [ABSTRACT FROM AUTHOR]

Uncontrolled waste generation and management difficulties are causing chaos in the ecosystem. Although it is vital to ease environmental pressures, right now there is no such practical strategy available for the treatment or utilisation of waste material. Because the Earth's resources are limited, a long‐term, sustainable, and sensible solution is necessary. Currently waste material has drawn a lot of attention as a renewable resource. Utilisation of residual biomass leftovers appears as a green and sustainable approach to lessen the waste burden on Earth while meeting the demand for bio‐based goods. Several biopolymers are available from renewable waste sources that have the potential to be used in a variety of industries for a wide range of applications. Natural and synthetic biopolymers have significant advantages over petroleum‐based polymers in terms of cost‐effectiveness, environmental friendliness, and user‐friendliness. Using waste as a raw material through industrial symbiosis should be taken into account as one of the strategies to achieve more economic and environmental value through inter‐firm collaboration on the path to a near‐zero waste society. This review extensively explores the different biopolymers which can be extracted from several waste material sources and that further have potential applications in food packaging industries to enhance the shelf life of perishables. This review‐based study also provides key insights into the different strategies and techniques that have been developed recently to extract biopolymers from different waste byproducts and their feasibility in practical applications for the food packaging business. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) exhibit unique properties of good ionic conductivity, electrochemical and thermal stability, and nonflammability, which make them promising candidates for biomedical applications. The limitations of their cytocompatibility are enhanced by using bioionic liquids (BILs) derived from biological molecules such as amines, sugars, and organic acids. BILs can be synthesized using tailorable chemistries that enable their immobilization onto biopolymers. For example, the cholinium ion and its derivatives have found significant interest in tissue engineering and drug delivery systems. Ion‐doped BIL‐functionalized polymers and their composites can also be used to design pH and electrical responsive actuators and sensors. The cytocompatibility and low immunogenicity of BIL‐functionalized polymers enable the possibilities of their use for power storage devices as well as implantable devices. These devices are gaining recognition and importance in nucleic acid delivery and molecular medicine. This review focuses on the recent advances of BILs in biomedical applications. Specifically, the review explores BILs as agents for biopolymer functionalization and highlights BILs as solvents for supermolecular ionic networks. [ABSTRACT FROM AUTHOR]

The deployment of structures that enable localized release of bioactive molecules can result in more efficacious treatment of disease and better integration of implantable bionic devices. The strategic design of a biopolymeric coating can be used to engineer the optimal release profile depending on the task at hand. As illustrative examples, here advances in delivery of drugs from bone, brain, ocular, and cardiovascular implants are reviewed. These areas are focused to highlight that both hard and soft tissue implants can benefit from controlled localized delivery. The composition of biopolymers used to achieve appropriate delivery to the selected tissue types, and their corresponding outcomes are brought to the fore. To conclude, key factors in designing drug‐loaded biopolymeric coatings for biomedical implants are highlighted. [ABSTRACT FROM AUTHOR]

Fracture of compliant materials is preceded by large deformations that reshape initially sharp cracks into rounded defects. This phenomenon, known as elastic crack blunting, is peculiar of rubber‐like polymers and soft biological tissues, such as skin, vessel walls, and tendons. With this work, we aim to provide a discussion on crack‐tip blunting and its implications in terms of tearing resistance and flaw tolerance of soft elastic materials. The characteristic features of the crack‐tip zone in the framework of nonlinear elasticity are reviewed analytically and with the help of finite element analyses on pure shear cracked geometries. Specifically, the strain‐hardening behavior typical of soft biological tissues is addressed, and we illustrate its effect on crack‐tip blunting, in terms of a local radius of curvature at the crack tip. A simplified geometrically nonlinear model, proposed to describe the progressive blunting at the crack tip and its effect on flaw tolerance, is validated through finite element analyses and experimental tests on silicone samples. We show how this can lead to a simplified criterion to define the fracture condition in nonlinear soft materials. [ABSTRACT FROM AUTHOR]

Sage leaf extract (SLE) is considered an excellent source of bioactive compounds mainly because of its high content of phenolics, widely known as natural antioxidants. This study aimed to compare the performance of free/encapsulated SLE by different coatings in protecting sunflower oil against oxidative deterioration. The coating materials were whey protein isolate and qodumeh seed gum at different ratios (1:0, 1:1, and 0:1). Each nanocapsule was analyzed for particle size, zeta potential, encapsulation efficiency, phenolics release, and SEM images. The total phenolic compounds of SLE were 31.12 mg GA/g. The antioxidant activity of SLE was increased in both DPPH and FRAP assays by increasing extract concentration from 50 to 250 ppm. All nanoparticles exhibited nanometric size, negative zeta potential, encapsulation efficiency higher than 60%, and gradual release during storage. The oxidative stability of sunflower oil with or without the incorporation of 250 ppm of free/encapsulated SLE was evaluated during 24 days of storage at 60°C. Peroxide value (PV), thiobarbituric acid value (TBA), oxidative stability index (OSI), color index (CI), and conjugated dienes (CD) were determined. COPM nanoparticles showed the lowest PV, TBA, CI, and CD but both SGUM and WHEY were more effective in delaying oil oxidation than TBHQ and free extract. Higher OSI was observed in oil‐containing nanoparticles with composite coating. Results obtained reinforce the use of whey protein isolate and qodumeh seed gum as a coating for encapsulating SLE to increase the shelf life of sunflower oil as a natural antioxidant. [ABSTRACT FROM AUTHOR]

Plants, as a large and complex system, are rich in a variety of natural bioactive constituents. It is crucial to enrich, isolate, purify and detect these natural products. Molecularly imprinted polymers (MIPs) are a class of polymers prepared by molecularly imprinted technology (MIT) that have specific recognition sites and are complementary to templates in shape, size, and binding groups. The synthesis and polymerization mechanism of MIPs are introduced. A variety of preparation methods for MIPs have been developed. MIPs can be classified into three types: non‐covalent molecularly imprinted, covalent molecularly imprinted, and semi‐covalent molecularly imprinted. MIPs usually consists of five parts: template, functional monomer, cross‐linker, initiator, and solvent/reagent. With the advantages of high‐specificity binding ability, MIPs have shown excellent efficacy in the separation, enrichment, and purification of plant active products, such as flavonoids, polyphenols, terpenoids, and other components, especially as specific adsorbent materials. Due to the high selectivity to target the analytes, MIPs have also been used as sensors to detect the bioactive constituents in plants. Undeniably, MIPs still face undeniable limitations in the application of plant natural products. The development of MIPs with high selectivity, strong affinity, cost‐effectiveness, sensitivity, and environmental friendliness are valuable and promising. [ABSTRACT FROM AUTHOR]

In this study, chitosan (C)/gelatin(G)/starch(S) composites incorporated pineapple peel extract (PPE) and aloe vera gel (AVG) were prepared by the casting method as antioxidant agents. Mechanical, water vapor permeability (WVP), moisture content, solubility, opacity, and color properties of the effects of PPE and AVG at different concentrations (0%, 10%, and 30%) were investigated. The prepared films were characterized by Fourier transform infrared spectroscopy in attenuated total reflection (ATR‐FTIR), X‐ray diffraction (XRD), Thermal gravimetric analysis (TGA), Scanning electron microscope (SEM), mechanical, water barrier, opacity, and color. PPE and AVG extract incorporated edible films improved thermal stability of edible films. Tensile strength decreased with the addition of extracts; the maximum tensile strength was 8.15 MPa for CGS film. The WVP of the films increased with the increasing PPE and AVG concentration. As a biological activity, the films inhibited the growth of gram‐positive (Staphylococcus aureus) and gram‐negative bacteria (Escherichia coli). With the addition of PPE and AVG to the CGS film, its antioxidant properties were enhanced. In addition, the prepared films were applied for strawberry coating both in the refrigerator and at room temperature. Consequently, these edible‐coated films can be used for active food packaging/coating to extend the shelf life of fruits. [ABSTRACT FROM AUTHOR]

Hygroscopic biopolymers like proteins and polysaccharides suffer from humidity‐dependent mechanical properties. Because humidity can vary significantly over the year, or even within a day, these polymers will not generally have stable properties during their lifetimes. On wheat gluten, a model highly hygroscopic biopolymer material, it is observed that larger/thicker samples can be significantly more mechanically stable than thinner samples. It is shown here that this is due to slow water diffusion, which, in turn, is due to the rigid polymer structure caused by the double‐bond character of the peptide bond, the many bulky peptide side groups, and the hydrogen bond network. More than a year is required to reach complete moisture saturation (≈10 wt.%) in a 1 cm thick plate of glycerol‐plasticized wheat gluten, whereas this process takes only one day for a 0.5 mm thick plate. The overall moisture uptake is also retarded by swelling‐induced mechanical effects. Hence, hygroscopic biopolymers are better suited for larger/thicker products, where the moisture‐induced changes in mechanical properties are smeared out over time, to the extent that the product remains sufficiently tough over climate changes, for example, throughout the course of a year. [ABSTRACT FROM AUTHOR]

In this study, biopolymer chitosan is presented as a template for synthesizing and shaping the mesoporous γ‐Al2O3 macrospheres. This porous γ‐Al2O3 granule has a high surface area (310 m2/g), high pore volume (.6148 cm3/g), and pore diameter between 2 and 10 nm. The full factorial design based on a mathematical model was implemented to study the acid concentration, chitosan amount, ammonia concentration, and aging time affecting the responses (Brunauer–Emmett–Teller surface area and pore volume). Predicted responses were found to be in satisfactory agreement with experimental values (R2 =.9580 and.9109, respectively). The adequacy of the model was examined by analyzing the residual distribution plots and Pareto graph. X‐ray diffraction, scanning electron microscopy (SEM), thermogravimetric analysis, and N2 adsorption/desorption techniques are employed to characterize the structure of the prepared γ‐alumina sample. [ABSTRACT FROM AUTHOR]

This investigation proposes a natural fiber surface modification approach based on the use of a system of coupling agents (CAs) to improve the mechanical properties of polymer composites made of flax fibers and low‐density polyethylene. This system combines the coating of the NaOH treated (mercerized) flax fibers by a CA (Epolene C18 [M‐C18]) in a solution under moderated heat (70°C–80°C), followed by the addition of 1% or 3% wt. of another CA (Epolene E43 [M‐E43]) during the injection molding. The comparison between the solution modified and the neat and mercerized flax fibers using scanning electron micrograph (SEM), thermogravimetric analysis (TGA), and density underscored some differences ascribed to the presence of M‐C18 onto the modified fibers. The mechanical properties showed that the combination of solution modification and direct introduction during the injection‐molding step of 1% of M‐E43 was efficient as the corresponding composites exhibited an improvement of 9.1%, 15.9%, and 11.1% of his tensile, flexural, and impact strengths respectively compared to the neat fiber composite. Due to their good impact and flexural strengths, these composites can be suitable for automotive parts such as keyboard. [ABSTRACT FROM AUTHOR]

The world population is severely affected by water scarcity, and it is an alarming issue that needs to be addressed urgently. Seawater desalination by solar‐driven evaporation is a promising technique to produce clean water. However, it is energy intensive and directs to a low water yield under natural sunlight. Therefore, the developments of new photothermal materials can reduce required energy for desired evaporation rates for efficient freshwater yield. Indeed, chitosan and polypyrrole‐based polymers are natural cationic copolymers, and their nanocomposites present well deal of interest for hydrogel structures due to their hydratable skeletons, and solar‐absorbing nature. Here, we report in situ polymerized Fe2O3@PPy/chitosan hydrogels as lightweight evaporation structures for solar‐powered evaporation under brine solutions (3.5 wt%). The polymeric network of Fe2O3@PPy/chitosan hydrogels builds in cross‐linked macroporous water channels, self‐floating, and a wide range of omnidirectional solar absorption (96%). The state‐of‐the‐art evaporation experiments demonstrate an efficient evaporation rate of water (1.80 kg m–2 h–1) and enhanced solar‐to‐vapor conversion efficiency (91%) as compared to other carbon‐based evaporation structures, excluding heat losses under 1 kW m–2 (one sun). Of note, the ultra‐black hydrogel surface stored enough thermal energy (39.6°C) under one sun solar irradiance due to the cationic polymeric network of Fe2O3@PPy/chitosan. A single‐step process for a freshwater supply that has been purified from various contaminants shows the potential of this device for real‐world applications. [ABSTRACT FROM AUTHOR]

The sanitary crisis caused by the SARS‐CoV‐2 has increased the demand for bioactive materials to mitigate coronavirus spread. The use of masks has been reported as an essential strategy to prevent coronavirus transmission, but they can become contaminated rapidly after use. Metals species containing compounds, especially those from the copper group, present properties that can be explored to suppress viral activity. Natural polymers, like alginate, can improve biocompatibility and adjust metal ion availability on hybrid coatings. This study assesses iron, copper, silver, and gold salts and their combination with biopolymers to design surfaces with virucidal properties. Viral inactivation assays with MHV‐3 coronavirus strain and cytotoxicity tests with L929 cells were conducted to the hybrid coatings on polypropylene masks. These coatings were characterized by scanning electron microscopy with energy dispersive spectroscopy, Fourier‐transform infrared spectroscopy with attenuated total reflectance device, and atomic absorption spectroscopy techniques. Multilayer coatings of alginate–copper sulfate presented 99.99% viral inactivation in a timely release of copper ions. [ABSTRACT FROM AUTHOR]

Silk fibroin was extracted from Bombyx mori cocoon and used as a biosorbent to remove Pb2+, CrO42−, Cu2+, and Co2+ from aqueous solutions. The sorption isotherms for the metals in fibroin were determined, and a thermodynamic analysis (ΔG°, ΔH°, and ΔS°) of the sorption process showed that the metal sorption in fibroin was physical, spontaneous, and endothermic. The sorption kinetics data was found to match well with the modified pseudo‐second‐order rate model, and the sorption rate constant was determined based on a rectified approach of model fitting. It was shown that the sorption rate constant was largely independent of the initial sorbate concentration, which was expected because it is a specific quantity characterizing the relationship between sorbate concentration and the rate of sorption. The metal‐loaded fibroin could be regenerated easily by stripping the metal off fibroin using ethylenediamine tetraacetic acid, and the sorption performance of the regenerated fibroin remained the same as pristine fibroin. When used repeatedly over 10 sorption‐regeneration cycles, the fibroin biosorbent showed no change in sorption capacity, which demonstrates the excellent stability and reusability of the fibroin biopolymer for metal capture from water. [ABSTRACT FROM AUTHOR]

The article presents the discussion on world news briefs. Topics include outbreak of monkeypox virus being in the process of procuring adequate tests with the support of the World Health Organization (WHO) as the viral disease spreading to non-endemic countries; and delivering a fixed volume of plant-based polyethylene furanoate (PEF) for use in packaging applications containing a fully recyclable beer bottle.

Building new value chains, through the valorization of biomass components for the development of innovative bio‐based products (BBPs) aimed at specific market sectors, will accelerate the transition from traditional production technologies to the concept of biorefineries. Recent studies aimed at mapping the most relevant innovations undergoing in the field of BBPs (Fabbri et al. 2019, Final Report of the Task 3 BIOSPRI Tender Study on Support to R&I Policy in the Area of Bio‐based Products and Services, delivered to the European Commission (DG RTD)), clearly showed the dominant position played by the plastics sector, in which new materials and innovative technical solutions based on renewable resources, concretely contribute to the achievement of relevant global sustainability goals. New sustainable solutions for the plastic sector, either bio‐based or bio‐based and biodegradable, have been intensely investigated in recent years. The global bioplastics and biopolymers market size is expected to grow from USD 10.5 billion in 2020 to USD 27.9 billion by 2025 (Markets and Markets, 2020, Bioplastics & Biopolymers Market by Type (Non‐Biodegradable/Bio‐Based, Biodegradable), End‐Use Industry (Packaging, Consumer Goods, Automotive & Transportation, Textiles, Agriculture & Horticulture), Region ‐ Global Forecast to 2025), and this high growth is driven primarily by the growth of the global packaging end‐use industry. Such relevant opportunities are the outcomes of intensive scientific and technological research devoted to the development of new materials with selected technical features, which can represent feasible substitutes for the fossil‐based plastic materials currently used in the packaging sectors and other main fields. This article offers a map of the latest developments connected to the plastic sector, achieved through the application of biotechnological routes for the preparation of completely new polymeric structures, or drop‐in substitutes derived from renewable resources, and it describes the specific role played by biotechnology in promoting and making this transition faster. [ABSTRACT FROM AUTHOR]

The agro‐food industry cannot today do without packaging to preserve and above all market its products. Plastic materials coming mainly from petrochemicals have taken a predominant place in the food packaging sector. They have become indispensable in many sectors, from fresh to frozen products, from meat and dairy products to fruit and vegetables or almost‐ready meals. Plastics are cheap, their lightness reduces transport costs, and their convenience is fundamental for out‐of‐home catering. However, plastics pose serious end‐of‐life issues. The development of materials that are more respectful of the consumer and the environment has become a major issue. In addition, the agro‐food industries generate significant quantities of waste or by‐products that are poorly or not at all recovered. However, these contain constituents that can be extracted or transformed to be compatible with packaging uses. Many molecules from waste materials are of particular interest for the development of active packaging such as biopolymers, bioactive agents, inorganic compounds, fibers, or nano‐ and micro‐objects. Providing bioactive functions such as antioxidants or antimicrobials can extend the shelf life of food while reducing the sophistication of plastic materials and thus improving their recycling. This article summarizes the main materials and constituents that can be recovered from waste and illustrates through several examples what could be the applications of such new, sustainable, and active packaging. [ABSTRACT FROM AUTHOR]

When air-dry thalli of Hypogymnia physodes are immersed in water, four main features characterize the rewetting phase. (1) There is an immediate and substantial release of gas, the 'wetting burst'. Although the released gas appears to be mostly CO[SUB2], it is non-metabolic in origin and probably the result of a previous adsorption of gas onto polysaccharide sheaths surrounding fungal hyphae. (2) There is a period of 1-2 h increased respiration, 'resaturation respiration', which, unlike basal respiration, is cyanide-sensitive. The cause of resaturation respiration remains obscure, but could result from exposure of respiratory substrate to enzymes from which they are normally separated. (3) There is a brief period (1-2 min) in which there is a rapid loss of organic and inorganic solutes from the thallus. Since water is a structural component of membranes, removal of some of this water during drying probably caused increased permeability so accounting for the losses observed. (4) There is a very rapid recovery of processes including photosynthesis and nutrient uptake. Even 10 s after rewetting, incorporation of [SUP32]p was 60% inhibited by DNP. The ecological significance of these features is discussed, particularly in relation to the apparent need of many lichens for periodic drying. [ABSTRACT FROM AUTHOR]

The body wall of the sea cucumber contains high amounts of sulfated glycans, which differ in structure from glycosaminoglycans of animal tissues and also from the fucose-rich sulfated polysaccharides isolated from marine algae and from the jelly coat of sea urchin eggs. In Ludwigothurea grisea, glycans can be separated into three fractions which differ in molecular mass and chemical composition. The fraction containing a high-molecularmass component has a high proportion of fucose and small amounts of amino sugars, whereas another fraction contains primarily a sulfated fucan. The third fraction, which represents the major portion of the sea cucumber polysaccharides, contains besides fucose, approximately equimolar proportions of glucuronic acid and amino sugars, and has a sulfate content higher than that in the other two fractions. Both D and L-isomers of fucose are found in these polysaccharides, and the sulfate is linked to the 0-3 position of the fucose residues. The attachment position of the sulfate groups to the glucuronic acid units and amino sugars is still undetermined. It is possible that these compounds are involved in maintaining the integrity of the sea cucumber's body wall, in analogy with the role of other macromolecules in the vertebrate connective tissue. [ABSTRACT FROM AUTHOR]

The sulfated polysaccharides in the tunic of Styela plicata occur as three fractions that differ markedly in molecular mass and chemical composition. The high-molecular-mass fraction has a high galactose content and a strong negative optical rotation while the low-molecular-mass fractions have a higher proportion of amino sugars and glucose. The galactose occurs in these polysaccharides entirely in the L-enantiomeric form. Although L-galactose is a constituent of several polysaccharides, this is the first report of sulfated polysaccharides that contain high amounts of L-galactose, and that lack the o enantiomorph of this sugar. Furthermore, the structure of the high-molecular-mass fraction, which is composed mainly ora core of α-L-galactopyranose residues, sulfated at position 3, linked glycosidically though position 1→4, and with non-sulfated L-galactopyranose non-reducing end-units, is unique among other previously described sulfated glycans. These data arc of considerable interest as they show an unusual example of possible variants of polyanionie glycans with structure function in living tissues. [ABSTRACT FROM AUTHOR]

A polymeric fraction containing the putative O-antigen has been isolated from the lipopolysaccharide of the reference strain (CDC 4534-60) for serogroup O9 of Serratia marcescens. The major component of the fraction was a polymer with a disaccharide repeating-unit of L-rhamnose (Rha) and 2-acetamido-2-deoxy-D-galactose (GalNAc) with the following structure: →3)D-GalpNAc(β1→3)L-Rhap(α1→. Evidence for the presence in the fraction of a similar, minor polymer containing 4-substituted rhamnose residues was provided by the NMR spectra, methylation analysis, and Smith degradation. [ABSTRACT FROM AUTHOR]