Structure-Activity Relationships for s-Block Metal/Co(III) Heterodinuclear Catalysts in Cyclohexene Oxide Ring-Opening Copolymerizations.

In homogeneous catalysis, uncovering structure-activity relationships remains very rare but invaluable to understand and rationally improve performances. Here, generalizable structure-activity relationships apply to a series of heterodinuclear polymerization catalysts featuring Co(III) and s-block metals M(I/II) (M= Na(I), K(I), Ca(II), Sr(II), Ba(II)). These are shown to apply to polycarbonate production by the ring-opening copolymerizations (ROCOP) of cyclohexene oxide (CHO) and carbon dioxide (CO2), conducted at high (20 bar) and low (1 bar) CO2 pressures, and to polyester production by copolymerization of cyclohexene oxide and phthalic anhydride (PA).

Property Prediction of Bio-Derived Block Copolymer Thermoplastic Elastomers Using Graph Kernel Methods.

Increasing the diversity of bio-based polymers is needed to address the combined problems of plastic pollution and greenhouse gas emissions. The magnitude of the problems necessitates rapid discovery of new materials; however, identification of appropriate chemistries maybe slow using current iterative methods. Machine learning (ML) methods could significantly expedite new material discovery and property identification.

Understanding the Effect of M(III) Choice in Heterodinuclear Polymerization Catalysts.

The ring-opening copolymerization (ROCOP) of epoxides with CO or anhydrides is a promising strategy to produce sustainable polycarbonates and polyesters. Currently, most catalysts are reliant on scarce and expensive cobalt as the active center, while more abundant aluminum and iron catalysts often suffer from lower activities. Here, two novel heterodinuclear catalysts, featuring abundant Al(III), Fe(III), and K(I) active centers, are synthesized, and their performance in the polymerization of four different monomer combinations is compared to that of their Co(III) analogue.

Clinical application of whole-genome sequencing in the management of extensively drug-resistant tuberculosis: a case report.

Background: Whole-genome sequencing (WGS)-based prediction of drug resistance in Mycobacterium tuberculosis has the potential to guide clinical decisions in the design of optimal treatment regimens.

Methods: We utilized WGS to investigate drug resistance mutations in a 32-year-old Tanzanian male admitted to Kibong'oto Infectious Diseases Hospital with a history of interrupted multidrug-resistant tuberculosis treatment for more than three years. Before admission, he received various all-oral bedaquiline-based multidrug-resistant tuberculosis treatment regimens with unfavourable outcomes.

Synergic Catalysis: the Importance of Intermetallic Separation in Co(III)K(I) Catalysts for Ring Opening Copolymerizations.

Dinuclear polymerization catalysts can show high activity and control. Understanding how to design for synergy between the metals is important to improving catalytic performances. Three heterodinuclear Co(III)K(I) catalysts, featuring very similar coordination chemistries, are prepared with different intermetallic separations.

Cyclic ether and anhydride ring opening copolymerisation delivering new ABB sequences in poly(ester--ethers).

Poly(ester--ethers) are interesting as they combine the ester linkage rigidity and potential for hydrolysis with ether linkage flexibility. This work describes a generally applicable route to their synthesis applying commercial monomers and yielding poly(ester--ethers) with variable compositions and structures. The ring-opening copolymerisation of anhydrides (A), epoxides (B) and cyclic ethers (C), using a Zr(iv) catalyst, produces either ABB or ABC type poly(ester--ethers).

Digital Light Processing to Afford High Resolution and Degradable CO-Derived Copolymer Elastomers.

Vat photopolymerization 3D printing has proven very successful for the rapid additive manufacturing (AM) of polymeric parts at high resolution. However, the range of materials that can be printed and their resulting properties remains narrow. Herein, we report the successful AM of a series of poly(carbonate-b-ester-b-carbonate) elastomers, derived from carbon dioxide and bio-derived ϵ-decalactone.

Lithium Borate Polycarbonates for High-Capacity Solid-State Composite Cathodes.

Improving composite cathode function is key to the success of the solid-state battery. Maximizing attainable cathode capacity and retention requires integrating suitable polymeric binders that retain a sufficiently high ionic conductivity and long-term chemo-mechanical stability of the cathode active material-solid-electrolyte-carbon mixture. Herein, we report block copolymer networks composed of lithium borate polycarbonates and poly(ethylene oxide) that improved the capacity (200 mAh g at 1.

Controlled Carbon Dioxide Terpolymerizations to Deliver Toughened yet Recyclable Thermoplastics.

Using CO polycarbonates as engineering thermoplastics has been limited by their mechanical performances, particularly their brittleness. Poly(cyclohexene carbonate) (PCHC) has a high tensile strength (40 MPa) but is very brittle (elongation at break <3%), which limits both its processing and applications. Here, well-defined, high molar mass CO terpolymers are prepared from cyclohexene oxide (CHO), cyclopentene oxide (CPO), and CO by using a Zn(II)Mg(II) catalyst.

Quantifying CO Insertion Equilibria for Low-Pressure Propene Oxide and Carbon Dioxide Ring Opening Copolymerization Catalysts.

While outstanding catalysts are known for the ring-opening copolymerization (ROCOP) of CO and propene oxide (PO), few are reported at low CO pressure. Here, a new series of Co(III)M(I) heterodinuclear catalysts are compared. The Co(III)K(I) complex shows the best activity (TOF = 1728 h) and selectivity (>90% polymer, >99% CO) and is highly effective at low pressures (<10 bar).

Kinetic Model for the Heterogeneous Biocatalytic Reactions Using Tethered Cofactors.

Understanding the mechanism of interfacial enzyme kinetics is critical to the development of synthetic biological systems for the production of value-added chemicals. Here, the interfacial kinetics of the catalysis of β-nicotinamide adenine dinucleotide (NAD)-dependent enzymes acting on NAD tethered to the surface of silica nanoparticles (SiNPs) has been investigated using two complementary and supporting kinetic approaches: enzyme excess and reactant (NAD) excess. Kinetic models developed for these two approaches characterize several critical reaction steps including reversible enzyme adsorption, complexation, decomplexation, and catalysis of the surface-bound enzyme/NAD complex.

High Molar Mass Polycarbonates as Closed-Loop Recyclable Thermoplastics.

Using carbon dioxide (CO) to make recyclable thermoplastics could reduce greenhouse gas emissions associated with polymer manufacturing. CO/cyclic epoxide ring-opening copolymerization (ROCOP) allows for >30 wt % of the polycarbonate to derive from CO; so far, the field has largely focused on oligocarbonates. In contrast, efficient catalysts for high molar mass polycarbonates are underinvestigated, and the resulting thermoplastic structure-property relationships, processing, and recycling need to be elucidated.

Alternatives to fluorinated binders: recyclable copolyester/carbonate electrolytes for high-capacity solid composite cathodes.

Optimising the composite cathode for next-generation, safe solid-state batteries with inorganic solid electrolytes remains a key challenge towards commercialisation and cell performance. Tackling this issue requires the design of suitable polymer binders for electrode processability and long-term solid-solid interfacial stability. Here, -polyester/carbonates are systematically designed as Li-ion conducting, high-voltage stable binders for cathode composites comprising of single-crystal LiNiMnCoO cathodes, LiPSCl solid electrolyte and carbon nanofibres.

Al(III)/K(I) Heterodinuclear Polymerization Catalysts Showing Fast Rates and High Selectivity for Polyester Polyols.

Low molar mass, hydroxyl end-capped polymers, often termed "polyols," are widely used to make polyurethanes, resins, and coatings and as surfactants in liquid formulations. Epoxide/anhydride ring-opening copolymerization (ROCOP) is a controlled polymerization route to make them, and its viability depends upon catalyst selection. In the catalysis, the polyester polyol molar masses and end-groups are controlled by adding specific but excess quantities of diols (vs catalyst), known as the chain transfer agent (CTA), to the polymerizations, but many of the best current catalysts are inhibited or even deactivated by alcohols.

Exploiting Organometallic Chemistry to Functionalize Small Cuprous Oxide Colloidal Nanocrystals.

The ligand chemistry of colloidal semiconductor nanocrystals mediates their solubility, band gap, and surface facets. Here, selective organometallic chemistry is used to prepare small, colloidal cuprous oxide nanocrystals and to control their surface chemistry by decorating them with metal complexes. The strategy is demonstrated using small (3-6 nm) cuprous oxide (CuO) colloidal nanocrystals (NC), soluble in organic solvents.

Designing a circular carbon and plastics economy for a sustainable future.

The linear production and consumption of plastics today is unsustainable. It creates large amounts of unnecessary and mismanaged waste, pollution and carbon dioxide emissions, undermining global climate targets and the Sustainable Development Goals. This Perspective provides an integrated technological, economic and legal view on how to deliver a circular carbon and plastics economy that minimizes carbon dioxide emissions.

Persistent Low-Level Variants in a Subset of Viral Genes Are Highly Predictive of Poor Outcome in Immunocompromised Patients With Cytomegalovirus Infection.

Background: Human cytomegalovirus (HCMV) is the most common and serious opportunistic infection after solid organ and hematopoietic stem cell transplantation. In this study, we used whole-genome HCMV data to investigate viral factors associated with the clinical outcome.

Methods: We sequenced HCMV samples from 16 immunocompromised pediatric patients with persistent viremia.

Oral nanotherapeutic formulation of insulin with reduced episodes of hypoglycaemia.

Injectable insulin is an extensively used medication with potential life-threatening hypoglycaemic events. Here we report on insulin-conjugated silver sulfide quantum dots coated with a chitosan/glucose polymer to produce a responsive oral insulin nanoformulation. This formulation is pH responsive, is insoluble in acidic environments and shows increased absorption in human duodenum explants and Caenorhabditis elegans at neutral pH.

Chemical Recycling of Commercial Poly(l-lactic acid) to l-Lactide Using a High-Performance Sn(II)/Alcohol Catalyst System.

Poly(l-lactic acid) (PLLA) is a leading commercial polymer produced from biomass, showing useful properties for plastics and fiber applications; after use, it is compostable. One area for improvement is postconsumer waste PLLA chemical recycling to monomer (CRM), i.e.

Transient non-coeliac gluten sensitivity (NCGS) with markedly reduced villous height/crypt depth ratio.

There is no confident evidence in the current literature to show or demonstrate that non-coeliac gluten sensitivity (NCGS) exclusively presents with mild or nearly normal duodenal mucosal abnormality. Gluten sensitive patients with negative serology and severe mucosal changes are labelled with the term seronegative coeliac disease (SNCS). There might be at least some overlap between NCGS and SNCD.