Updates on Hydrogen Value Chain: A Strategic Roadmap.

A strategic roadmap for noncarbonized fuels is a global priority, and the reduction of carbon dioxide emissions is a key focus of the Paris Agreement to mitigate the effects of rising temperatures. In this context, hydrogen is a promising noncarbonized fuel, but the pace of its implementation will depend on the engineering advancements made at each step of its value chain. To accelerate its adoption, various applications of hydrogen across industries, transport, power, and building sectors have been identified, where it can be used as a feedstock, fuel, or energy carrier and storage.

Reaction of 2,5-dihydroxy-[1,4]-benzoquinone with nucleophiles - -substitution addition/elimination.

2,5-Dihydroxy-[1,4]-benzoquinone (DHBQ) reacts readily with secondary amines to 2,5-diamino compounds and with thiols to the corresponding 2,5-dithioether derivatives. The literature has been inconclusive about the detailed mechanism, as both ipso-substitution at C-2/C-5 and the sequence of C-3/C-6 addition and C-2/C-5 elimination would give exactly the same products. By means of selectively 13C isotopically labelled DHBQ it was demonstrated that the reaction with morpholine is an ipso-substitution, while the reaction with benzenethiol and 1-hexanethiol proceeds according to the addition/elimination mechanism, and the reaction with the respective thiolates according to both mechanisms in parallel.

Runx2/Osterix and Zinc Uptake Synergize to Orchestrate Osteogenic Differentiation and Citrate Containing Bone Apatite Formation.

Citrate is essential to biomineralization of the bone especially as an integral part of apatite nanocomposite. Citrate precipitate of apatite is hypothesized to be derived from mesenchymal stem/stromal cells (MSCs) upon differentiation into mature osteoblasts. Based on C-labeled signals identified by solid-state multinuclear magnetic resonance analysis, boosted mitochondrial activity and carbon-source replenishment of tricarboxylic acid cycle intermediates coordinate to feed forward mitochondrial anabolism and deposition of citrate.

Design of cellulose ether-based macromolecular prodrugs of ciprofloxacin for extended release and enhanced bioavailability.

The present study reveals the syntheses of hydroxypropylcellulose‑(HPC) and hydroxyethylcellulose‑(HEC) based macromolecular prodrugs (MPDs) of ciprofloxacin (CIP) using homogeneous reaction methodology. Covalently loaded drug content (DC) of each prodrug was quantified using UV-Vis spectrophotometry to determine degree of substitution (DS). HPC-ciprofloxacin (HPC-CIP) conjugates showed DS of CIP in the range 0.

High-Yielding Syntheses of Crown Ether-Based Pyridyl Cryptands.

Pyridinium bis(trifluoromethylsulfonyl)imide (PyTFSI)-templated syntheses of 2,6-pyridyl cryptands of cis(4,4')-dibenzo-30-crown-10 (3a), the p-bromobenzyloxy derivative 3b, bis(m-phenylene)-32-crown-10 (5), cis(4,4')-dibenzo-27S-crown-9 (7), cis(4,4')-dibenzo-27L-crown-9 (9), and cis(4,4')-dibenzo-24-crown-8 (11) are reported. Here we provide a fast (12 h), high-yielding (89%, 74%, 80%, and 62% for 3a, 3b, 5, and 9, respectively) templation method without the use of a syringe pump. The yields for 7 (19%) and 11 (26%) were lower than with the previous pseudo-high-dilution method, indicating ineffective templation in these cases.

ABAB Phthalocyanines: Scaffolds for Building Unprecedented Donor-π-Acceptor Chromophores.

Unique donor-π-acceptor phthalocyanines have been synthesized through the asymmetric functionalization of an ABAB phthalocyanine, crosswise functionalized with two iodine atoms through Pd-catalyzed cross-coupling reactions with adequate electron-donor and electron-acceptor moieties. These push-pull molecules have been optically and electrochemically characterized, and their ability to perform as chromophores for dye-sensitized solar cells has been tested.

Remote Actuation of Magnetic Nanoparticles For Cancer Cell Selective Treatment Through Cytoskeletal Disruption.

Motion of micron and sub-micron size magnetic particles in alternating magnetic fields can activate mechanosensitive cellular functions or physically destruct cancer cells. However, such effects are usually observed with relatively large magnetic particles (>250 nm) that would be difficult if at all possible to deliver to remote sites in the body to treat disease. Here we show a completely new mechanism of selective toxicity of superparamagnetic nanoparticles (SMNP) of 7 to 8 nm in diameter to cancer cells.

Biodegradation of nanocrystalline cellulose by two environmentally-relevant consortia.

Nanocellulose is growing in popularity due to its versatile properties and applications. However, there is a void of knowledge regarding the environmental fate of nanocellulose and the response of environmental microbial communities that are historically adapted to non-nano cellulose forms. Given its distinction in terms of size and chemical and physical properties, nanocellulose could potentially resist biodegradation and/or pose a xenobiotic influence on microbial communities during wastewater treatment or in receiving environments.

Reducing the heterogeneity of xylan through processing.

Glycerol thermal processing (GTP) of hardwood biomass at temperatures between 200 and 240°C facilitated stepwise biopolymer fractionation, while limiting significant degradation of the major hemicellulose, glucuronoxylan, into water-extractable oligosaccharides. After GTP pretreatment and sequential water and organic solvent extraction, up to 80% of the initial xylan remained in the pretreated biomass. The majority of the xylan from GTP pretreated and water/solvent extracted biomass was removed using a mild alkali extraction and the composition was compared to xylan directly isolated from untreated hardwood.

Diphenylphosphino Styrene-Containing Homopolymers: Influence of Alkylation and Mobile Anions on Physical Properties.

Conventional free radical polymerization and post-alkylation of 4-diphenylphosphino styrene (DPPS) generate a new class of high-molecular-weight phosphonium-containing homopolymers with tunable thermal, viscoelastic, and wetting properties. Post-alkylation and subsequent anion exchange provide an effective method for tuning Tg values and thermal stability as a function of alkyl chain length and counteranion selection (X(-) , BF4 (-) , TfO(-) , and Tf2 N(-) ). Rheological characterization facilitates the generation of time-temperature-superposition (TTS) pseudomaster curves and subsequent analysis of frequency sweeps at various temperatures reveals two relaxation modes corresponding to long-range segmental motion and the onset of viscous flow.

Luteinizing Hormone Releasing Hormone-Targeted Cisplatin-Loaded Magnetite Nanoclusters for Simultaneous MR Imaging and Chemotherapy of Ovarian Cancer.

Given the superior soft tissue contrasts obtained by MRI and the long residence times of magnetic nanoparticles (MNPs) in soft tissues, MNP-based theranostic systems are being developed for simultaneous imaging and treatment. However, development of such theranostic nanoformulations presents significant challenges of balancing the therapeutic and diagnostic functionalities in order to achieve optimum effect from both. Here we developed a simple theranostic nanoformulation based on magnetic nanoclusters (MNCs) stabilized by a bisphosphonate-modified poly(glutamic acid)--(ethylene glycol) block copolymer and complexed with cisplatin.

Morphology selection via geometric frustration in chiral filament bundles.

In assemblies, the geometric frustration of a locally preferred packing motif leads to anomalous behaviours, from self-limiting growth to defects in the ground state. Here, we demonstrate that geometric frustration selects the equilibrium morphology of cohesive bundles of chiral filaments, an assembly motif critical to a broad range of biological and synthetic nanomaterials. Frustration of inter-filament spacing leads to optimal shapes of self-twisting bundles that break the symmetries of packing and of the underlying inter-filament forces, paralleling a morphological instability in spherical two-dimensional crystals.

Functionalized Celluloses with Regular Substitution Pattern by Glycosynthase-Catalyzed Polymerization.

Control of the monomer sequence in polymers is extraordinarily difficult by chemical synthesis, though Nature routinely exerts such control, including in the biosynthesis of polysaccharides. This inability has prevented us from being able to match the exquisite structure-activity control exhibited in biosynthesis of bioactive natural polysaccharides. We here address a powerful approach, whereby enzyme-catalyzed polymerization of properly modified building blocks is introduced as a simple route affording polysaccharides with controlled sequence and functionalization pattern.

Preparation of Bottlebrush Polymers via a One-Pot Ring-Opening Polymerization (ROP) and Ring-Opening Metathesis Polymerization (ROMP) Grafting-Through Strategy.

Bottlebrush polymers are synthesized using a tandem ring-opening polymerization (ROP) and ring-opening metathesis polymerization (ROMP) strategy. For the first time, ROP and ROMP are conducted sequentially in the same pot to yield well-defined bottlebrush polymers with molecular weights in excess of 10(6) Da. The first step of this process involves the synthesis of a polylactide macromonomer (MM) via ROP of d,l-lactide initiated by an alcohol-functionalized norbornene.

Highly Conductive and Thermally Stable Ion Gels with Tunable Anisotropy and Modulus.

A new liquid-crystalline ion gel exhibits unprecedented properties: conductivity up to 8 mS cm(-1) , thermal stability to 300 °C, and electrochemical window to 6.1 V, as well as adjustable transport anisotropy (up to 3.5×) and elastic modulus (0.

An Efficient, Regioselective Pathway to Cationic and Zwitterionic N-Heterocyclic Cellulose Ionomers.

Cationic derivatives of cellulose and other polysaccharides are attractive targets for biomedical applications due to their propensity for electrostatically binding with anionic biomolecules, such as nucleic acids and certain proteins. To date, however, relatively few practical synthetic methods have been described for their preparation. Herein, we report a useful and efficient strategy for cationic cellulose ester salt preparation by the reaction of 6-bromo-6-deoxycellulose acetate with pyridine or 1-methylimidazole.

Amphiphilic Cellulose Ethers Designed for Amorphous Solid Dispersion via Olefin Cross-Metathesis.

The design of cellulose ether-based amphiphiles has been difficult and limited because of the harsh conditions typically required for appending ether moieties to cellulose. Olefin cross-metathesis recently has been shown to be a valuable approach for appending a variety of functional groups to cellulose ethers and esters, provided that an olefin handle for metathesis can be attached. This synthetic pathway gives access to these functional derivatives under very mild conditions and at high efficiency.

Imidazolium-Containing ABA Triblock Copolymers as Electroactive Devices.

Two-step reversible addition-fragmentation chain transfer (RAFT) polymerization and two subsequent postpolymerization modification steps afforded well-defined ABA triblock copolymers featuring mechanically reinforcing polystyrene outer blocks and 1-methylimidazole-neutralized poly(acrylic acid)-based central blocks. Size exclusion chromatography and (1)H NMR spectroscopy confirmed predictable molecular weights and narrow distributions. The ionic liquid (IL) 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([EMIm][OTf]) was incorporated at 30 wt % into polymeric films.

Dendritic Elastin-like Peptides: The Effect of Branching on Thermoresponsiveness.

Elastin-like peptides (ELPs) have been used widely to confer thermoresponsive characteristics onto various materials, but to this point mostly linear ELPs have been studied. A class of linear and dendritic (branched) ELPs based on the GLPGL pentamer repeat unit was synthesized using an on-resin divergent strategy. The effect of peptide topology on the transition temperature (Tt) was examined using circular dichroism to study the peptide secondary structure transition and turbidity to measure the macroscopic phase transition (coacervation).

Phosphonium-containing diblock copolymers from living anionic polymerization of 4-diphenylphosphino styrene.

Living anionic polymerization of 4-diphenylphosphino styrene (DPPS) achieved well-defined homopolymers, poly(DPPS-b-S) styrenic block copolymers, and poly(I-b-DPPS) diene-based diblock copolymers with predictable molecular weights and narrow polydispersities. In situ FTIR spectroscopy monitored the anionic polymerization of DPPS and tracked monomer consumption for kinetic analysis. Post-alkylation enabled controlled placement of phosphonium functionality in poly(I-b-DPPS) diblock copolymers, producing well-defined phosphonium-containing block copolymers with low degrees of compositional heterogeneity.

Extended release and enhanced bioavailability of moxifloxacin conjugated with hydrophilic cellulose ethers.

Macromolecular prodrugs (MPDs) of moxifloxacin were fabricated based on hydroxypropylcellulose (HPC) and hydroxyethylcellulose (HEC). UV/Vis spectrophotometry was employed to determine covalently loaded drug content (DC) of each conjugate. The degree of substitution (DS) of moxifloxacin attained ranged from 0.

Regioselective synthesis of cationic 6-deoxy-6-(N,N,N-trialkylammonio)curdlan derivatives.

Curdlan, a bioactive β-1,3-glucan, is of intense interest for pharmaceutical and biomedical applications. Cationic derivatives of curdlan and other polysaccharides are especially attractive for their potential to interact in controlled fashion with proteins, among many other possible applications, but relatively few methods exist for their synthesis. Herein we report a regioselective method for preparation of cationic, water-soluble 6-(N,N,N-trialkylammonio)-6-deoxycurdlan salts by reaction of 6-bromo-6-deoxycurdlan and its 2,4-O-diesters with trialkylamines.

Influence of resveratrol release on the tissue response to mechanically adaptive cortical implants.

The stability and longevity of recordings obtained from intracortical microelectrodes continues to remain an area of concern for neural interfacing applications. The limited longevity of microelectrode performance has been associated with the integrity of the blood brain barrier (BBB) and the neuroinflammatory response to the microelectrode. Here, we report the investigation of an additive approach that targets both mechanical and chemical factors believed to contribute to chronic BBB instability and the neuroinflammatory response associated with implanted intracortical microelectrodes.

Directed cell growth in multi-zonal scaffolds for cartilage tissue engineering.

Articular cartilage serves as a low-friction cushion in synovial joints and is vital for mammalian skeletal movements. Due to its avascular nature and the low cell density, the tissue has a limited ability to regenerate, and damage due to injury, wear and tear, or disease usually requires surgical intervention. While articular cartilage had been predicted to be one of the first tissues to be successfully engineered, it proved to be challenging to reproduce the complex architecture and biomechanical properties of the native tissue.