Cyclic and Linear Tetrablock Copolymers Synthesized at Speed and Scale by Lewis Pair Polymerization of a One-Pot (Meth)acrylic Mixture and Characterized at Multiple Levels.

Cyclic block copolymers (BCP) are fundamentally intriguing materials, but their synthetic challenges that demand precision in controlling both the monomer sequence and polymer topology limit access to AB and ABC block architectures. Here, we show that cyclic ABAB tetra-BCPs (ABAB) and their linear counterpart (ABAB) can be readily obtained at a speed and scale from one-pot (meth)acrylic monomer mixtures, through coupling the Lewis pair polymerization's unique compounded-sequence control with its precision in topology control. This approach achieves fast (<15 min) and quantitative (>99%) conversion to tetra-BCPs of predesignated linear or cyclic topology at scale (40 g) in a one-pot procedure, precluding the needs for repeated chain extensions, stoichiometric addition steps, dilute conditions, and postsynthetic modifications, and/or postsynthetic ring-closure steps.

Toughening Brittle Bio-P3HB with Synthetic P3HB of Engineered Stereomicrostructures.

Poly(3-hydroxybutyrate) (P3HB), a biologically produced, biodegradable natural polyester, exhibits excellent thermal and barrier properties but suffers from mechanical brittleness, largely limiting its applications. Here we report a mono-material product design strategy to toughen stereoperfect, brittle bio or synthetic P3HB by blending it with stereomicrostructurally engineered P3HB. Through tacticity ([mm] from 0 to 100 %) and molecular weight (M to 788 kDa) tuning, high-performance synthetic P3HB materials with tensile strength to ≈30 MPa, fracture strain to ≈800 %, and toughness to 126 MJ m (>110× tougher than bio-P3HB) have been produced.

Dynamic crosslinking compatibilizes immiscible mixed plastics.

The global plastics problem is a trifecta, greatly affecting environment, energy and climate. Many innovative closed/open-loop plastics recycling or upcycling strategies have been proposed or developed, addressing various aspects of the issues underpinning the achievement of a circular economy. In this context, reusing mixed-plastics waste presents a particular challenge with no current effective closed-loop solution.

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The design of facile synthetic routes to well-defined block copolymers (BCPs) from direct polymerization of one-pot comonomer mixtures, rather than traditional sequential additions, is both fundamentally and technologically important. Such synthetic methodologies often leverage relative monomer reactivity toward propagating species exclusively and therefore are rather limited in monomer scope and control over copolymer structure. The recently developed compounded sequence control (CSC) by Lewis pair polymerization (LPP) utilizes synergistically both thermodynamic () and kinetic () differentiation to precisely control BCP sequences and suppress tapering and misincorporation errors.

Synthesis and biological evaluation of semi-synthetic albocycline analogs.

Albocycline (ALB) is a unique macrolactone natural product with potent, narrow-spectrum activity against methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-intermediate (VISA), and vancomycin-resistant S. aureus (VRSA) strains (MIC = 0.5-1.

Sedation and Analgesia in Transportation of Acutely and Critically Ill Patients.

Transportation of acutely or critically ill patients is a challenge for health care providers. Among the difficulties that providers face is the balance between adequate sedation and analgesia for the transportation event and maintaining acceptable respiratory and physiologic parameters of the patient. This article describes common challenges in providing sedation and analgesia during various phases of transport.

Routine screening for eosinophilic esophagitis in patients presenting with dysphagia.

Background: Eosinophilic esophagitis (EoE) is a clinicopathologic disorder first described in 1978 which has gained significant recognition over the past 10 years. Numerous prevalence studies have been performed around the globe, both in pediatric and adult populations documenting a prevalence between 0.002% and 6.

Use of intravenous proton-pump inhibitors in a teaching hospital practice.

Objective: To evaluate intravenous proton-pump inhibitor (IV PPI) prescribing in a single academic teaching hospital.

Methods: A retrospective pilot study of 107 patients in a single United States military teaching hospital was conducted over a 1-month period. Clinical data were collected and analyzed for demographic features, prior medication use, admission hemoglobin level, service prescribing the IV PPI, indication for IV PPI, IV PPI treatment duration, gastroenterology consultant use, endoscopic findings, and blood products given.

Bilateral brachial artery occlusion decreases internal carotid artery volume flow: a simple adjunct for cerebral protection?

Purpose: To investigate if a decrease in internal carotid artery (ICA) blood flow occurs with bilateral brachial artery occlusion (BBO), which may improve the effectiveness of cerebral protection devices during carotid interventions.

Methods: Thirty-two asymptomatic patients (21 men; mean age 67 years) with carotid atherosclerosis between 15% and 79% were enrolled in the study. Carotid duplex ultrasound was followed by volume flow rate (VF) determination in the right ICA, external carotid (ECA), and vertebral arteries.

Nonaqueous suspensions of laponite and montmorillonite.

It is shown how stable, nonaqueous suspensions of fully exfoliated smectite clays such as Laponite and montmorillonite can be obtained. Suspensions in toluene and in a branched aliphatic solvent (polydecene) were characterized using elemental analysis, rheometry, and small-angle X-ray scattering. For Laponite, stable suspensions were obtained by adsorbing a dichain poly(isobutylene) based stabilizer to the particles.

Graft patency is not the only clinical predictor of success after exclusion and bypass of popliteal artery aneurysms.

Purpose: The traditional measure of success after exclusion and bypass of popliteal artery aneurysm (PAA) is graft patency. In addition to fate of the bypass, we hypothesize that late outcome after surgical treatment of PAA is influenced by completeness of exclusion.

Methods: Thirty patients who underwent 41 reconstructions for PAA over a 10-year period were reviewed.