Graft-through Synthesis and Assembly of Janus Bottlebrush Polymers from A-Branch-B Diblock Macromonomers.

We report the synthesis of Janus bottlebrush block copolymers by graft-through polymerization of branched diblock macromonomers. Self-assembly of the bottlebrushes was characterized by small-angle X-ray scattering, atomic force microscopy, and scanning electron microscopy. Phase separation and packing models of the bottlebrushes were computed, and their self-assembly behavior was corroborated experimentally in bulk and in thin films.

Comparative Assessment of Models and Methods To Calculate Grid Electricity Emissions.

Due to the complexity of power systems, tracking emissions attributable to a specific electrical load is a daunting challenge but essential for many environmental impact studies. Currently, no consensus exists on appropriate methods for quantifying emissions from particular electricity loads. This paper reviews a wide range of the existing methods, detailing their functionality, tractability, and appropriate use.

Accumulation of Peptidoglycan O-Acetylation Leads to Altered Cell Wall Biochemistry and Negatively Impacts Pathogenesis Factors of Campylobacter jejuni.

Campylobacter jejuni is a leading cause of bacterial gastroenteritis in the developed world. Despite its prevalence, its mechanisms of pathogenesis are poorly understood. Peptidoglycan (PG) is important for helical shape, colonization, and host-pathogen interactions in C.

Block Co-PolyMOCs by Stepwise Self-Assembly.

We report a stepwise assembly strategy for the integration of metal-organic cages (MOCs) into block copolymers (BCPs). This approach creates "block co-polyMOC" (BCPMOC) materials whose microscopic structures and mechanical properties are readily tunable by adjusting the size and geometry of the MOCs and the composition of the BCPs. In the first assembly step, BCPs functionalized with a pyridyl ligand on the chain end form star-shaped polymers triggered by metal-coordination-induced MOC assembly.

Iterative Exponential Growth Synthesis and Assembly of Uniform Diblock Copolymers.

Studies on the phase segregation of unimolecular block copolymers (BCPs) are limited by a lack of reliable, versatile methods for the synthesis of such polymers on the preparative scale. Herein, we describe an advancement of Iterative Exponential Growth (IEG) wherein chiral allyl-based IEG oligomers are subjected to thiol-ene reactions and converted into unimolecular BCPs. With this strategy we have synthesized uniform BCPs with molar masses up to 12.

Reactions of Persistent Carbenes with Hydrogen-Terminated Silicon Surfaces.

Surface passivation has enabled the development of silicon-based solar cells and microelectronics. However, a number of emerging applications require a paradigm shift from passivation to functionalization, wherein surface functionality is installed proximal to the silicon surface. To address this need, we report here the use of persistent aminocarbenes to functionalize hydrogen-terminated silicon surfaces via Si-H insertion reactions.

Clinical Outcomes of Transplanted Modified Bone Marrow-Derived Mesenchymal Stem Cells in Stroke: A Phase 1/2a Study.

Background And Purpose: Preclinical data suggest that cell-based therapies have the potential to improve stroke outcomes.

Methods: Eighteen patients with stable, chronic stroke were enrolled in a 2-year, open-label, single-arm study to evaluate the safety and clinical outcomes of surgical transplantation of modified bone marrow-derived mesenchymal stem cells (SB623).

Results: All patients in the safety population (N=18) experienced at least 1 treatment-emergent adverse event.

Universal Cyclic Topology in Polymer Networks.

Polymer networks invariably possess topological defects: loops of different orders which have profound effects on network properties. Here, we demonstrate that all cyclic topologies are a universal function of a single dimensionless parameter characterizing the conditions for network formation. The theory is in excellent agreement with both experimental measurements of hydrogel loop fractions and Monte Carlo simulations without any fitting parameters.

Cannabis Use and Outcomes in Patients With Aneurysmal Subarachnoid Hemorrhage.

Background And Purpose: The incidence of cannabis use in patients with aneurysmal subarachnoid hemorrhage (aSAH) and its impact on morbidity, mortality, and outcomes are unknown. Our objective was to evaluate the relationship between cannabis use and outcomes in patients with aSAH.

Methods: Records of consecutive patients admitted with aSAH between 2010 and 2015 were reviewed.

Light-Controlled Radical Polymerization: Mechanisms, Methods, and Applications.

The use of light to mediate controlled radical polymerization has emerged as a powerful strategy for rational polymer synthesis and advanced materials fabrication. This review provides a comprehensive survey of photocontrolled, living radical polymerizations (photo-CRPs). From the perspective of mechanism, all known photo-CRPs are divided into either (1) intramolecular photochemical processes or (2) photoredox processes.

Early Hypoalbuminemia is an Independent Predictor of Mortality in Aneurysmal Subarachnoid Hemorrhage.

Background: Hypoalbuminemia has been identified as a predictor of morbidity and mortality in critically ill patients. There is very little data on the significance and the prognostic value of hypoalbuminemia in patients with aneurysmal subarachnoid hemorrhage (aSAH). This study analyzed the impact of hypoalbuminemia on patient presentation, complications, and outcomes.

Embolization of a congenital arteriovenous fistula of the internal maxillary artery: A case report and review of the literature.

A 13 year-old girl with a congenital carotid-jugular fistula presented with a pulsatile mass and a thrill on the left side of her neck. Angiography showed a fistula between the left internal maxillary artery and the jugular vein. The patient underwent coil embolization using a transarterial balloon-assisted technique and one week later, a transvenous approach.

Twelve Principles for Green Energy Storage in Grid Applications.

The introduction of energy storage technologies to the grid could enable greater integration of renewables, improve system resilience and reliability, and offer cost effective alternatives to transmission and distribution upgrades. The integration of energy storage systems into the electrical grid can lead to different environmental outcomes based on the grid application, the existing generation mix, and the demand. Given this complexity, a framework is needed to systematically inform design and technology selection about the environmental impacts that emerge when considering energy storage options to improve sustainability performance of the grid.

Iterative exponential growth of stereo- and sequence-controlled polymers.

Chemists have long sought sequence-controlled synthetic polymers that mimic nature's biopolymers, but a practical synthetic route that enables absolute control over polymer sequence and structure remains a key challenge. Here, we report an iterative exponential growth plus side-chain functionalization (IEG+) strategy that begins with enantiopure epoxides and facilitates the efficient synthesis of a family of uniform >3 kDa macromolecules of varying sequence and stereoconfiguration that are coupled to produce unimolecular polymers (>6 kDa) with sequences and structures that cannot be obtained using traditional polymerization techniques. Selective side-chain deprotection of three hexadecamers is also demonstrated, which imbues each compound with the ability to dissolve in water.

Scalable synthesis of sequence-defined, unimolecular macromolecules by Flow-IEG.

We report a semiautomated synthesis of sequence and architecturally defined, unimolecular macromolecules through a marriage of multistep flow synthesis and iterative exponential growth (Flow-IEG). The Flow-IEG system performs three reactions and an in-line purification in a total residence time of under 10 min, effectively doubling the molecular weight of an oligomeric species in an uninterrupted reaction sequence. Further iterations using the Flow-IEG system enable an exponential increase in molecular weight.

PEGylated N-Heterocyclic Carbene Anchors Designed To Stabilize Gold Nanoparticles in Biologically Relevant Media.

N-Heterocyclic carbenes (NHCs) have emerged as versatile ligands for surface functionalization. Their ease of synthesis and ability to form strong bonds with a range of substrates provide a unique complement to traditional surface modification methods. Gold nanoparticles (NPs) are a particularly useful class of materials whose applications intimately depend on surface functionalization.

Morel-LAvallee lesion initially diagnosed as quadriceps contusion: ultrasound, MRI, and importance of early intervention.

Morel-Lavallee lesions (MLL) are rare, closed degloving injuries caused by trauma that delivers a shearing force to the soft tissue most commonly of the hip. If not treated in the acute and subacute setting these lesions are often complicated by re-accumulation of fluid, infection, or chronic pain. We present a unique case of a recurrent, massive medial knee/thigh MLL in which proper treatment was delayed due to initial diagnosis of a quadriceps contusion.

Visible-Light-Controlled Living Radical Polymerization from a Trithiocarbonate Iniferter Mediated by an Organic Photoredox Catalyst.

Living radical polymerization of acrylates and acrylamides from trithiocarbonate iniferters using a compact fluorescent lamp (CFL) bulb and 10-phenylphenothiazine as an organic photoredox catalyst is reported. With this system, chain growth can be efficiently switched between "on" and "off" in response to visible light. Polymer molar masses increase linearly with conversion, and narrow molar mass distributions are obtained.

Dialysis arteriovenous fistula causing subclavian steal syndrome in the absence of subclavian artery stenosis.

We present a rare cause of subclavian steal syndrome secondary to a dialysis arteriovenous fistula (AVF). A 69-year-old female with end-stage renal disease presented with ataxia and recurrent fainting spells. Angiography revealed normal subclavian arteries bilaterally, a right VA origin occlusion, and an apparent left VA origin occlusion.

Dual Role for 1,2,4,5-Tetrazines in Polymer Networks: Combining Diels-Alder Reactions and Metal Coordination To Generate Functional Supramolecular Gels.

The inverse-electron demand Diels-Alder cycloaddition of tetrazines and olefins has emerged as a powerful coupling reaction for the formation of polymer gels with diverse applications. Tetrazines are also excellent ligands for metal atoms. For example, 3,6-bis(2-pyridyl)-1,2,4,5-tetrazines (bptz) have been used to generate discrete supramolecular Mbptz metal clusters and extended 2D grid structures.

Emissions reductions from expanding state-level renewable portfolio standards.

In the United States, state-level Renewable Portfolio Standards (RPS) have served as key drivers for the development of new renewable energy. This research presents a method to evaluate emissions reductions and costs attributable to new or expanded RPS programs by integrating a comprehensive economic dispatch model and a renewable project selection model. The latter model minimizes incremental RPS costs, accounting for renewable power purchase agreements (PPAs), displaced generation and capacity costs, and net changes to a state's imports and exports.

Narrow-spectrum inhibitors of Campylobacter jejuni flagellar expression and growth.

Campylobacter jejuni is a major cause of food-borne illness due to its ability to reside within the gastrointestinal tracts of chickens. Multiple studies have identified the flagella of C. jejuni as a major determinant of chicken colonization.