Anomalous photochromism and mechanochromism of a linear naphthopyran enabled by a polarizing dialkylamine substituent.

In contrast to common angular naphthopyrans that exhibit strong photochromic and mechanochromic behavior, constitutionally isomeric linear naphthopyrans are typically not photochromic, due to the putative instability of the completely dearomatized merocyanine product. The photochemistry of linear naphthopyrans is thus relatively understudied compared to angular naphthopyrans, while the mechanochromism of linear naphthopyrans remains completely unexplored. Here we demonstrate that the incorporation of a polarizing dialkylamine substituent enables photochromic and mechanochromic behavior from polymers containing a novel linear naphthopyran motif.

Naphthopyran molecular switches and their emergent mechanochemical reactivity.

Naphthopyran molecular switches undergo a ring-opening reaction upon external stimulation to generate intensely colored merocyanine dyes. Their unique modularity and synthetic accessibility afford exceptional control over their properties and stimuli-responsive behavior. Commercial applications of naphthopyrans as photoswitches in photochromic ophthalmic lenses have spurred an extensive body of work exploring naphthopyran-merocyanine structure-property relationships.

Remote control of mechanochemical reactions under physiological conditions using biocompatible focused ultrasound.

External control of chemical reactions in biological settings with spatial and temporal precision is a grand challenge for noninvasive diagnostic and therapeutic applications. While light is a conventional stimulus for remote chemical activation, its penetration is severely attenuated in tissues, which limits biological applicability. On the other hand, ultrasound is a biocompatible remote energy source that is highly penetrant and offers a wide range of functional tunability.

Lifestyle strategies after intentional weight loss: results from the MAINTAIN-pc randomized trial.

Introduction/purpose: Weight maintenance following intentional weight loss is challenging and often unsuccessful. Physical activity and self-monitoring are strategies associated with successful weight loss maintenance. However, less is known about the type and number of lifestyle strategies used following intentional weight loss.

Validation of an Accurate and Expedient Initial Rates Method for Characterizing Mechanophore Reactivity.

Understanding structure-mechanochemical reactivity relationships is important for informing the rational design of new stimuli-responsive polymers. To this end, establishing accurate reaction kinetics for mechanophore activation is a key objective. Here, we validate an initial rates method that enables the accurate and rapid determination of rate constants for ultrasound-induced mechanochemical transformations.

Mechanical Force Enables an Anomalous Dual Ring-Opening Reaction of Naphthodipyran.

Multimodal mechanophores that exhibit complex mechanochromic behavior beyond the typical binary response are capable of distinguishing between multiple stress states through discrete changes in color. Naphthodipyran photoswitches contain two pyran rings fused to a central naphthalene core and represent a potentially promising framework for multimodal reactivity. However, the concurrent ring opening of both pyran moieties has previously proven inaccessible via photochemical activation.

Changes in Pain Catastrophizing and Fear-Avoidance Beliefs as Mediators of Early Physical Therapy on Disability and Pain in Acute Low-Back Pain: A Secondary Analysis of a Clinical Trial.

Objective: The Fear-Avoidance Model (FAM) of chronic pain posits that pain catastrophizing and fear-avoidance beliefs are prognostic for disability and chronicity. In acute low-back pain, early physical therapy (PT) is effective in reducing disability in some patients. How early PT impacts short- and long-term changes in disability for patients with acute pain is unknown.

Amino acid divergence in the ligand-binding pocket of Vibrio LuxR/HapR proteins determines the efficacy of thiophenesulfonamide inhibitors.

The quorum-sensing signaling systems in Vibrio bacteria converge to control levels of the master transcription factors LuxR/HapR, a family of highly conserved proteins that regulate gene expression for bacterial behaviors. A compound library screen identified 2-thiophenesulfonamide compounds that specifically inhibit Vibrio campbellii LuxR but do not affect cell growth. We synthesized a panel of 50 thiophenesulfonamide compounds to examine the structure-activity relationship effects on Vibrio quorum sensing.

The Relationship Between Neighborhood Deprivation and Perceived Changes for Pain-Related Experiences Among US Patients with Chronic Low Back Pain During the COVID-19 Pandemic.

Objective: Disruptions caused by the COVID-19 pandemic could disproportionately affect the health of vulnerable populations, including patients experiencing persistent health conditions (i.e., chronic pain), along with populations living within deprived, lower socioeconomic areas.

Generation of an Elusive Permanent Merocyanine via a Unique Mechanochemical Reaction Pathway.

We report the discovery of a 2-naphtho[1,2-]pyran mechanophore that produces a permanent merocyanine dye upon mechanochemical activation, in contrast to the reversible product generated photochemically. Experiments suggest that the irreversibility of the mechanically generated merocyanine is due to a unique reaction in which the scission of an ester C-O bond reveals a β-hydroxy ketone that locks the merocyanine through an intramolecular H-bonding interaction. In addition to demonstrating the reactivity using solution-phase ultrasonication, permanent merocyanine generation is also achieved in solid polymeric materials.

Optimization of Spinal Manipulative Therapy Protocols: A Factorial Randomized Trial Within a Multiphase Optimization Framework.

Spinal manipulative therapy (SMT) is a common nonpharmacological treatment for low back pain (LBP). Although generally supported by systematic reviews and practice guidelines, clinical trials evaluating SMT have been characterized by small effect sizes. This study adopts a Multiphase Optimization Strategy framework to examine individual components of an SMT delivery protocol using a single-blind trial with the goal of identifying and optimizing a multicomponent SMT protocol.

Physical Therapy Referral From Primary Care for Acute Back Pain With Sciatica : A Randomized Controlled Trial.

Background: Few studies have examined primary care management for acute sciatica, including referral to physical therapy.

Objective: To evaluate whether early referral to physical therapy reduced disability more than usual care (UC) alone for patients with acute sciatica.

Design: Randomized controlled clinical trial.

A metabolic pathway for bile acid dehydroxylation by the gut microbiome.

The gut microbiota synthesize hundreds of molecules, many of which influence host physiology. Among the most abundant metabolites are the secondary bile acids deoxycholic acid (DCA) and lithocholic acid (LCA), which accumulate at concentrations of around 500 μM and are known to block the growth of Clostridium difficile, promote hepatocellular carcinoma and modulate host metabolism via the G-protein-coupled receptor TGR5 (ref. ).

Prevalence of Retinal Diseases and Associated Risk Factors in an African Population From Mwanza, Tanzania.

Background And Objective: To determine the prevalence of retinal disease among a population in Mwanza, Tanzania, and to identify relevant risk factors for retinal disorders in this cohort.

Patients And Methods: A cross-sectional population-based study was conducted in Mwanza, Tanzania, among patients older than 18 years. Participants completed a demographics survey and underwent an ophthalmic examination that included fundus photography.

Designing naphthopyran mechanophores with tunable mechanochromic behavior.

Mechanochromic molecular force probes conveniently report on stress and strain in polymeric materials through straightforward visual cues. We capitalize on the versatility of the naphthopyran framework to design a series of mechanochromic mechanophores that exhibit highly tunable color and fading kinetics after mechanochemical activation. Structurally diverse naphthopyran crosslinkers are synthesized and covalently incorporated into silicone elastomers, where the mechanochemical ring-opening reactions are achieved under tension to generate the merocyanine dyes.

Force-Dependent Multicolor Mechanochromism from a Single Mechanophore.

We report a bis-naphthopyran mechanophore that exhibits force-dependent changes in visible absorption. A series of polymers incorporating a chain-centered bis-naphthopyran mechanophore was synthesized and mechanically activated using ultrasonication. By varying the length of the polymer chains, the force delivered to the mechanophore is modulated systematically.

Association of electroretinography with visual outcomes after ophthalmic artery chemosurgery for retinoblastoma in ICRb D and E eyes.

Importance: Predictions of visual outcomes are useful in clinical and family decisions regarding treatment for retinoblastoma. Very little has been published on the association of post-treatment visual acuity with pre-treatment electroretinography (ERG), which can be performed on infants too young to reliably quantify visual acuity.

Objective: To report associations of pre-treatment ERG with post-treatment visual acuity in eyes with advanced retinoblastoma treated with ophthalmic artery chemosurgery (OAC).

Mechanochemical Regulation of a Photochemical Reaction.

We introduce the concept of mechanochemically gated photoswitching. Mechanical regulation of a photochemical reaction is exemplified using a newly designed mechanophore based on a cyclopentadiene-maleimide Diels-Alder adduct. Ultrasound-induced mechanical activation of the photochemically inert mechanophore in polymers generates a diarylethene photoswitch via a retro-[4 + 2] cycloaddition reaction that photoisomerizes between colorless and colored states upon exposure to UV and visible light.

Diffusion-Weighted Imaging and Post-contrast Enhancement in Differentiating Optic Neuritis and Non-arteritic Anterior Optic Neuropathy.

Non-arteritic anterior ischaemic optic neuropathy (NAION) and optic neuritis (ON) may be difficult to distinguish early in their disease courses. Our goal was to determine if specific magnetic resonance imaging characteristics differentiate acute NAION from ON. Neuroradiologists, masked to diagnosis, reviewed the diffusion-weighted imaging (DWI) and post-contrast enhancement (PCE) characteristics of the optic nerve in 140 eyes.

Relationship of Sodium Intake and Blood Pressure Varies With Energy Intake: Secondary Analysis of the DASH (Dietary Approaches to Stop Hypertension)-Sodium Trial.

Dietary Na recommendations are expressed as absolute amounts (mg/d) rather than as Na density (mg/kcal). Our objective was to determine whether the strength of the relationship of Na intake with blood pressure (BP) varied with energy intake. The DASH (Dietary Approaches to Stop Hypertension)-Sodium trial was a randomized feeding trial comparing 2 diets (DASH and control) and 3 levels of Na density.

Corneal biomechanical properties after laser-assisted in situ keratomileusis and photorefractive keratectomy.

Background: The purpose of this study was to evaluate the effects of laser-assisted in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) on corneal biomechanical properties.

Methods: We used the ocular response analyzer to measure corneal hysteresis (CH) and corneal resistance factor (CRF) before and after refractive surgery.

Results: In all, 230 eyes underwent LASIK and 115 eyes underwent PRK without mitomycin C (MMC).

Factors Influencing Occupational Therapists' Decision to Supervise Fieldwork Students.

The purpose of this study was to identify factors that influence the decision to supervise a Level II occupational therapy fieldwork student. A survey was sent to occupational therapists identified from licensure boards and alumni rosters, including those who have and have not supervised students (n = 548). The results identified both positive and negative influences along with predictive factors of supervising a student.