Flash heating process for efficient meat preservation.

Maintaining food safety and quality is critical for public health and food security. Conventional food preservation methods, such as pasteurization and dehydration, often change the overall organoleptic quality of the food products. Herein, we demonstrate a method that affects only a thin surface layer of the food, using beef as a model.

Facile preparation of near-monodisperse oligocellulose and its elastomeric derivatives with tunable mechanical properties.

Oligocellulose (OC) with low polydispersity indices has been produced in large quantities using an improved method of acid-assisted hydrolysis, in which long cellulose chains disintegrate in concentrated phosphoric acid at moderately elevated temperatures. The hydrolysis time has been reduced by three orders of magnitude without compromising the overall yield of the process or the quality of OC products. The efficient production of high-quality OCs in large quantities allows for developing OC-derived elastomeric materials.

Highly stable, antiviral, antibacterial cotton textiles via molecular engineering.

Cotton textiles are ubiquitous in daily life and are also one of the primary mediums for transmitting viruses and bacteria. Conventional approaches to fabricating antiviral and antibacterial textiles generally load functional additives onto the surface of the fabric and/or their microfibres. However, such modifications are susceptible to deterioration after long-term use due to leaching of the additives.

A cellulose-derived supramolecule for fast ion transport.

Supramolecular frameworks have been widely synthesized for ion transport applications. However, conventional approaches of constructing ion transport pathways in supramolecular frameworks typically require complex processes and display poor scalability, high cost, and limited sustainability. Here, we report the scalable and cost-effective synthesis of an ion-conducting (e.

A high-performance hydroxide exchange membrane enabled by Cu-crosslinked chitosan.

Ion exchange membranes are widely used to selectively transport ions in various electrochemical devices. Hydroxide exchange membranes (HEMs) are promising to couple with lower cost platinum-free electrocatalysts used in alkaline conditions, but are not stable enough in strong alkaline solutions. Herein, we present a Cu-crosslinked chitosan (chitosan-Cu) material as a stable and high-performance HEM.

Efficient production of oligomeric chitin with narrow distributions of degree of polymerization using sonication-assisted phosphoric acid hydrolysis.

A method of producing oligomeric chitin using sonication-assisted phosphoric acid hydrolysis was introduced. The processing was continuous and scalable. Oligomeric chitin fractions with narrow distributions of degree of polymerization were obtained by differential precipitation using ethanol as precipitating agent at different ethanol-to-phosphoric-acid-solution volume ratios.

Copper-coordinated cellulose ion conductors for solid-state batteries.

Although solid-state lithium (Li)-metal batteries promise both high energy density and safety, existing solid ion conductors fail to satisfy the rigorous requirements of battery operations. Inorganic ion conductors allow fast ion transport, but their rigid and brittle nature prevents good interfacial contact with electrodes. Conversely, polymer ion conductors that are Li-metal-stable usually provide better interfacial compatibility and mechanical tolerance, but typically suffer from inferior ionic conductivity owing to the coupling of the ion transport with the motion of the polymer chains.

Solvent-Assisted Fractionation of Oligomeric Cellulose and Reversible Transformation of Cellulose II and IV.

Oligomeric cellulose with an average degree of polymerization of 7.68 and a polydispersity of 1.04 has been fractionated using solution processes.

Effect of Carbon Chain Length, Ionic Strength, and pH on the In Vitro Release Kinetics of Cationic Drugs from Fatty-Acid-Loaded Contact Lenses.

This paper explores the use of fatty acids in silicone hydrogel contact lenses for extending the release duration of cationic drugs. Drug release kinetics was dependent on the carbon chain length of the fatty acid loaded in the lens, with 12-, 14- and 18-carbon chain length fatty acids increasing the uptake and the release duration of ketotifen fumarate (KTF) and tetracaine hydrochloride (THCL). Drug release kinetics from oleic acid-loaded lenses was evaluated in phosphate buffer saline (PBS) at different ionic strengths ( = 167, 500, 1665 mM); the release duration of KTF and THCL was decreased with increasing ionic strength of the release medium.

Extended delivery of cationic drugs from contact lenses loaded with unsaturated fatty acids.

This paper describes the use of surface-active anionic unsaturated fatty acids in commercial contact lenses to extend drug release duration and regulate delivery dosage. We studied the effect of oleic acid on the in vitro release kinetics of three cationic drugs, and two anionic drugs from silicone hydrogel contact lenses. The release duration of the cationic drugs: tetracaine hydrochloride, bupivacaine hydrochloride, and ketotifen fumarate was significantly extended from less than a day to more than a month because of the presence of oleic acid in the contact lenses.

Formation of Drug-Participating Catanionic Aggregates for Extended Delivery of Non-Steroidal Anti-Inflammatory Drugs from Contact Lenses.

This paper focuses on extending drug release duration from contact lenses by incorporating catanionic aggregates. The aggregates consist of a long-chain cationic surfactant, i.e.

Decoupling Ionic and Electronic Pathways in Low-Dimensional Hybrid Conductors.

The construction of two-dimensional (2D) layered compounds for nanofluidic ion transport has recently attracted increasing interest due to the facile fabrication, tunable channel size, and high flux of these materials. Here we design a nacre-mimetic graphite-based nanofluidic structure in which the nanometer-thick graphite flakes are wrapped by negatively charged nanofibrillated cellulose (NFC) fibers to form multiple 2D confined spacings as nanochannels for rapid cation transport. At the same time, the graphite-NFC structure exhibits an ultralow electrical conductivity (σ ≤ 10 S/cm), even when the graphite concentration is up to 50 wt %, well above the percolation threshold (∼1 wt %).

Molecular partitioning in ternary solutions of cellulose.

Neutron scattering measurements on the structure and dynamics of ternary solutions of microcrystalline cellulose (MC) in mixtures of an ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate and a polar organic solvent dimethylformamide (DMF) have shown that MC can be fully dissolved in solvent mixtures. Data also show the molecular partitioning of IL into coexisting states. The structure partitioning is manifested as IL adsorbed to cellulose molecules with additional IL self-assembled to form clusters in solution, while the dynamics partitioning shows dynamical heterogeneities of the IL with slow dynamics resembling neat IL and fast dynamics being coupled with the solvent.

Cellulose ionic conductors with high differential thermal voltage for low-grade heat harvesting.

Converting low-grade heat into useful electricity requires a technology that is efficient and cost effective. Here, we demonstrate a cellulosic membrane that relies on sub-nanoscale confinement of ions in oxidized and aligned cellulose molecular chains to enhance selective diffusion under a thermal gradient. After infiltrating electrolyte into the cellulosic membrane and applying an axial temperature gradient, the ionic conductor exhibits a thermal gradient ratio (analogous to the Seebeck coefficient in thermoelectrics) of 24 mV K-more than twice the highest value reported until now.

A nanofluidic ion regulation membrane with aligned cellulose nanofibers.

The advancement of nanofluidic applications will require the identification of materials with high-conductivity nanoscale channels that can be readily obtained at massive scale. Inspired by the transpiration in mesostructured trees, we report a nanofluidic membrane consisting of densely packed cellulose nanofibers directly derived from wood. Numerous nanochannels are produced among an expansive array of one-dimensional cellulose nanofibers.

Neutron scattering in the biological sciences: progress and prospects.

The scattering of neutrons can be used to provide information on the structure and dynamics of biological systems on multiple length and time scales. Pursuant to a National Science Foundation-funded workshop in February 2018, recent developments in this field are reviewed here, as well as future prospects that can be expected given recent advances in sources, instrumentation and computational power and methods. Crystallography, solution scattering, dynamics, membranes, labeling and imaging are examined.

Phase Separation and Stack Alignment in Aqueous Cellulose Nanocrystal Suspension under Weak Magnetic Field.

Isotropic-nematic (I-N) transitions in cellulose nanocrystal (CNC) suspension and self-assembled structures in the isotropic and nematic phases were investigated using scattering and microscopy methods. A CNC suspension with a mass fraction of 7.4% spontaneously phase separated into an isotropic phase of 6.

Spray-Processed Composites with High Conductivity and Elasticity.

Highly conductive elastic composites were constructed using multistep solution-based fabrication methods that included the deposition of a nonwoven polymer fiber mat through solution blow spinning and nanoparticle nucleation. High nanoparticle loading was achieved by introducing silver nanoparticles into the fiber spinning solution. The presence of the silver nanoparticles facilitates improved uptake of silver nanoparticle precursor in subsequent processing steps.

Entropic stabilization of folded RNA in crowded solutions measured by SAXS.

Non-coding RNAs must fold into specific structures that are stabilized by metal ions and other co-solutes in the cell's interior. Large crowder molecules such as PEG stabilize a bacterial group I ribozyme so that the RNA folds in low Mg concentrations typical of the cell's interior. To understand the thermodynamic origins of stabilization by crowder molecules, small angle X-ray scattering was used to measure the folding and helix assembly of a bacterial group I ribozyme at different temperatures and in different MgCl and polyethylene glycol (PEG) concentrations.

Molecular crowding overcomes the destabilizing effects of mutations in a bacterial ribozyme.

The native structure of the Azoarcus group I ribozyme is stabilized by the cooperative formation of tertiary interactions between double helical domains. Thus, even single mutations that break this network of tertiary interactions reduce ribozyme activity in physiological Mg(2+) concentrations. Here, we report that molecular crowding comparable to that in the cell compensates for destabilizing mutations in the Azoarcus ribozyme.

NMR Water Self-Diffusion and Relaxation Studies on Sodium Polyacrylate Solutions and Gels in Physiologic Ionic Solutions.

Water self-diffusion coefficients and longitudinal relaxation rates in sodium polyacrylate solutions and gels were measured by NMR, as a function of polymer content and structure in a physiological concentration range of monovalent and divalent cations, Ca and Na. Several physical models describing the self-diffusion of the solvent were applied and compared. A free-volume model was found to be in good agreement with the experimental results over a wide range of polymer concentrations.

Morphotropic phase boundaries in ferromagnets: Tb(1-x)Dy(x)Fe2 alloys.

The structure and properties of the ferromagnet Tb(1-x)Dy(x)Fe(2) are explored through the morphotropic phase boundary (MPB) separating ferroic phases of differing symmetry. Our synchrotron data support a first order structural transition, with a broadening MPB width at higher temperatures. The optimal point for magnetomechanical applications is not centered on the MPB but lies on the rhombohedral side, where the high striction of the rhombohedral majority phase combines with the softened anisotropy of the MPB.

Crowders perturb the entropy of RNA energy landscapes to favor folding.

Biological macromolecules have evolved to fold and operate in the crowded environment of the cell. We have shown previously that molecular crowding stabilizes folded RNA structures. Here we report SAXS measurements on a 64 kDa bacterial group I ribozyme in the presence of mono- and divalent ions and PEG crowders of different molecular weight.

Self-assembled block copolymer photonic crystal for selective fructose detection.

The use of one-dimensional photonic crystals fabricated from a self-assembled lamellar block copolymer as a sensitive and selective fructose sensor is investigated. The polystyrene-b-poly(2-vinyl pyridine) (PS-b-P2VP) films are functionalized with 2-(bromomethyl)phenylboronic acid. The boronic acid moiety confined within the lamellar morphology can reversibly bind to sugars such as fructose, imparting the photonic properties of the PS-b-P2VP film.

Color changing block copolymer films for chemical sensing of simple sugars.

We investigated the use of functionalized photonic block copolymer films for the detection of glucose. Polystyrene-b-poly(2-vinyl pyridine) (PS-b-P2VP) block copolymers were chemically functionalized with 2-(bromomethyl)phenylboronic acid and cast into films that reflect a visible color when exposed to aqueous media. The 2-(bromomethyl)phenylboronic acid functionality can reversibly bind to glucose.