Size-resolved aerosol at a Coastal Great Lakes Site: Impacts of new particle formation and lake spray.

The quantification of aerosol size distributions is crucial for understanding the climate and health impacts of aerosols, validating models, and identifying aerosol sources. This work provides one of the first continuous measurements of aerosol size distribution from 1.02 to 8671 nm near the shore of Lake Michigan. The data were collected during the Lake Michigan Ozone Study (LMOS 2017), a comprehensive air quality measurement campaign in May and June 2017. The time-resolved (2-min) size distribution are reported herein alongside meteorology, remotely sensed data, gravimetric filters, and gas-phase variables. Mean concentrations of key aerosol parameters include PM2.5 (6.4 µg m-3), number from 1 to 3 nm (1.80x104 cm-3) and number greater than 3 nm (8x103 cm-3). During the field campaign, approximately half of days showed daytime ultrafine burst events, characterized by particle growth from sub 10 nm to 25-100 nm. A specific investigation of ultrafine lake spray aerosol was conducted due to enhanced ultrafine particles in onshore flows coupled with sustained wave breaking conditions during the campaign. Upon closer examination, the relationships between the size distribution, wind direction, wind speed, and wave height did not qualitatively support ultrafine particle production from lake spray aerosol; statistical analysis of particle number and wind speed also failed to show a relationship. The alternative hypothesis of enhanced ultrafine particles in onshore flow originating mainly from new particle formation activity is supported by multiple lines of evidence.

Development of Spatio-Temporal Land Use Regression Models for Fine Particulate Matter and Wood-Burning Tracers in Temuco, Chile.

Biomass burning is common in much of the world, and in some areas, residential wood-burning has increased. However, air pollution resulting from biomass burning is an important public health problem. A sampling campaign was carried out between May 2017 and July 2018 in over 64 sites in four sessions, to develop a spatio-temporal land use regression (LUR) model for fine particulate matter (PM) and wood-burning tracers levoglucosan and soluble potassium (Ksol) in a city heavily impacted by wood-burning. The mean (sd) was 46.5 (37.4) µg m-3 for PM2.5, 0.607 (0.538) µg m-3 for levoglucosan, and 0.635 (0.489) µg m-3 for Ksol. LUR models for PM2.5, levoglucosan, and Ksol had a satisfactory performance (LOSOCV R2), explaining 88.8%, 87.4%, and 87.3% of the total variance, respectively. All models included sociodemographic predictors consistent with the pattern of use of wood-burning in homes. The models were applied to predict concentrations surfaces and to estimate exposures for an epidemiological study.

On the Ability of the N-O Bond to Support a Stable Stereogenic Axis: Peptide-Catalyzed Atroposelective N-Oxidation.

During studies of atroposelective, peptide-catalyzed N-oxidations of pyridines, we observed lower-than-expected barriers to atropisomerization for these stereodynamic processes under the reaction conditions. Mechanistic studies indicate a hydrogen bond-assisted racemization mechanism intrinsic to both the starting materials and products. We also identified a protonation-dependent barrier to rotation that operates for the starting materials alone. Nonetheless, several substrates were amenable to atroposelective N-oxidations via kinetic resolution, yielding krel values of up to 12.6 and the isolation of one N-oxide with >99:1 er after recrystallization.

Companion animal veterinarians discuss aspects of one health with pet owners during most veterinary appointments.

OBJECTIVE: To examine the prevalence and context of one-health conversations between veterinarians and clients in companion animal practice. SAMPLE: A random selection of 60 companion animal veterinarians; a convenience sample of 917 interactions from Southern Ontario, Canada. Of these, 100 audio-video-recorded interactions including 47 of 60 veterinarians were randomly selected for inclusion in this study. METHODS: Audio-video recordings were made of veterinarian-client-patient interactions between November 2017 and January 2019. A researcher-generated coding framework was developed and used to assess the prevalence and content of one-health topics communicated during veterinary appointments. RESULTS: Of the interactions assessed, 60 were preventive care and 40 were health problem appointments. Further, 78% (78/100) included at least 1 discussion related to one health. One-health topics included zoonoses (28% [28/100]), animal behavior (25% [25/100]), illness/disease (20% [20/100]), activity level/exercise (16% [16/100]), nutrition (16% [16/100]), dentistry (6% [6/100]), body weight (3% [3/100]), animal welfare (3% [3/100]), dog/cat bites (2% [2/100]), cannabis (2% [2/100]), and aging (1% [1/100]). Zoonotic diseases were mentioned in 65 appointments, 28 of which evolved into a one-health discussion. Antibiotics were discussed in 27 appointments, none of which were discussed in relation to one health (eg, antimicrobial resistance). CLINICAL RELEVANCE: Findings suggest that one-health topics are raised within most veterinary appointments. Opportunities exist for more comprehensive one-health conversations between veterinarians and their clients, particularly in relation to zoonotic diseases and antimicrobials.

Submicron Aerosol Composition and Source Contribution across the Kathmandu Valley, Nepal, in Winter.

The Kathmandu valley experiences an average wintertime PM1 concentration of ∼100 µg m-3 and daily peaks over 200 µg m-3. We present ambient nonrefractory PM1 chemical composition, and concentration measured by a mini aerosol mass spectrometer (mAMS) sequentially at Dhulikhel (on the valley exterior), then urban Ratnapark, and finally suburban Lalitpur in winter 2018. At all sites, organic aerosol (OA) was the largest contributor to combined PM1 (C-PM1) (49%) and black carbon (BC) was the second largest contributor (21%). The average background C-PM1 at Dhulikhel was 48 µg m-3; the urban enhancement was 120% (58 µg m-3). BC had an average of 6.1 µg m-3 at Dhulikhel, an urban enhancement of 17.4 µg m-3. Sulfate (SO4) was 3.6 µg m-3 at Dhulikhel, then 7.5 µg m-3 at Ratnapark, and 12.0 µg m-3 at Lalitpur in the brick kiln region. Chloride (Chl) increased by 330 and 250% from Dhulikhel to Ratnapark and Lalitpur on average. Positive matrix factorization (PMF) identified seven OA sources, four primary OA sources, hydrocarbon-like (HOA), biomass burning (BBOA), trash burning (TBOA), a sulfate-containing local OA source (sLOA), and three secondary oxygenated organic aerosols (OOA). OOA was the largest fraction of OA, over 50% outside the valley and 36% within. HOA (traffic) was the most prominent primary source, contributing 21% of all OA and 44% of BC. Brick kilns were the second largest contributor to C-PM1, 12% of OA, 33% of BC, and a primary emitter of aerosol sulfate. These results, though successive, indicate the importance of multisite measurements to understand ambient particulate matter concentration heterogeneity across urban regions.

Wintertime Air Quality across the Kathmandu Valley, Nepal: Concentration, Composition, and Sources of Fine and Coarse Particulate Matter.

The Kathmandu Valley in Nepal experiences poor air quality, especially in the dry winter season. In this study, we investigated the concentration, chemical composition, and sources of fine and coarse particulate matter (PM2.5, PM10, and PM10-2.5) at three sites within or near the Kathmandu Valley during the winter of 2018 as part of the second Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE 2). Daily PM2.5 concentrations were very high throughout the study period, ranging 72-149 µg m-3 at the urban Ratnapark site in Kathmandu, 88-161 µg m-3 at the suburban Lalitpur site, and 40-74 µg m-3 at rural Dhulikhel on the eastern rim of the Kathmandu Valley. Meanwhile, PM10 ranged 194-309, 174-377, and 64-131 µg m-3, respectively. At the Ratnapark site, crustal materials from resuspended soil contributed an average of 11% of PM2.5 and 34% of PM10. PM2.5 was largely comprised of organic carbon (OC, 28-30% by mass) and elemental carbon (EC, 10-14% by mass). As determined by chemical mass balance source apportionment modeling, major PM2.5 OC sources were garbage burning (15-21%), biomass burning (10-17%), and fossil fuel (14-26%). Secondary organic aerosol (SOA) contributions from aromatic volatile organic compounds (13-23% OC) were larger than those from isoprene (0.3-0.5%), monoterpenes (0.9-1.4%), and sesquiterpenes (3.6-4.4%). Nitro-monoaromatic compounds-of interest due to their light-absorbing properties and toxicity-indicate the presence of biomass burning-derived SOA. Knowledge of primary and secondary PM sources can facilitate air quality management in this region.

Effects of Atmospheric Aging Processes on Nascent Sea Spray Aerosol Physicochemical Properties.

The effects of atmospheric aging on single-particle nascent sea spray aerosol (nSSA) physicochemical properties, such as morphology, composition, phase state, and water uptake, are important to understanding their impacts on the Earth's climate. The present study investigates these properties by focusing on the aged SSA (size range of 0.1-0.6 µm) and comparing with a similar size range nSSA, both generated at a peak of a phytoplankton bloom during a mesocosm study. The aged SSAs were generated by exposing nSSA to OH radicals with exposures equivalent to 4-5 days of atmospheric aging. Complementary filter-based thermal optical analysis, atomic force microscopy (AFM), and AFM photothermal infrared spectroscopy were utilized. Both nSSA and aged SSA showed an increase in the organic mass fraction with decreasing particle sizes. In addition, aging results in a further increase of the organic mass fraction, which can be attributed to new particle formation and oxidation of volatile organic compounds followed by condensation on pre-existing particles. The results are consistent with single-particle measurements that showed a relative increase in the abundance of aged SSA core-shells with significantly higher organic coating thickness, relative to nSSA. Increased hygroscopicity was observed for aged SSA core-shells, which had more oxygenated organic species. Rounded nSSA and aged SSA had similar hygroscopicity and no apparent changes in the composition. The observed changes in aged SSA physicochemical properties showed a significant size-dependence and particle-to-particle variability. Overall, results showed that the atmospheric aging can significantly influence the nSSA physicochemical properties, thus altering the SSA effects on the climate.

Aerosol Mass Spectral Profiles from NAMaSTE Field-Sampled South Asian Combustion Sources.

Unit mass resolution mass spectral profiles of nonrefractory submicron aerosol were retrieved from undersampled atmospheric emission sources common to South Asia using a "mini" aerosol mass spectrometer. Emission sources including wood- and dung-fueled cookstoves, agricultural residue burning, garbage burning, engine exhaust, and coal-fired brick kilns were sampled during the 2015 Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE) campaign. High-resolution peak fitting estimates of the mass spectra were used to characterize ions found within each source profile and help identify mass spectral signatures unique to aerosol emissions from the investigated source types. The first aerosol mass spectral profiles of dung burning, charcoal burning, garbage burning, and brick kilns are provided in this work. The online aerosol mass spectra show that organics were generally the dominant component of the nonrefractory aerosol. However, inorganic aerosol components including ammonium and chloride were significant in dung- and charcoal-fired cookstove emissions and sulfate compounds were major components of the coal-fired brick kiln emissions. Organic mass spectra from both the charcoal burning and zigzag brick kiln were dominated by nitrogen-containing ions thought to be from the electron ionization of amines and amides contained in the emissions. The mixed garbage burning emissions profiles were dominated by plastic combustion with very low fractions of organic markers associated with biomass burning. The plastic burning emissions were associated with enhanced organic signal at mass-to-charge (m/z) 104 and m/z 166, which could be useful fragment ion indicators for garbage burning in ambient aerosol profiles. Finally, a framework for the identification of emission sources using the unit mass resolution organic mass fractions at m/z 55 (f 55), m/z 57 (f 57), and m/z 60 (f 60) is proposed in this work. Plotting the ratio of f 55 to f 57 versus f 60 is found to be effective for the identification of emissions by the fuel type and even useful in separating emissions of similar source types. Although the sample size was limited, these results give further context to the aerosol and gas-phase emission factors presented in other NAMaSTE works and provide a critical reference for future aerosol composition measurements in South Asia.

Characterization of sub-pollen particles in size-resolved atmospheric aerosol using chemical tracers.

Pollen grains may contain allergens that exacerbate allergic respiratory diseases like asthma and rhinitis. In the presence of water, pollen grains (10-100 µm) can rupture to produce sub-pollen particles (SPP) with diameters <2.5 µm, which in comparison to intact pollen grains, have longer atmospheric lifetimes and greater penetration to the lower lung. The current study examines SPP, fungal spores, and bacteria in size-resolved atmospheric particulate matter (PM) using chemical and biological tracers. During springtime tree pollen season in Iowa City, Iowa, fine particle (PM2.5) concentrations of fructose (a pollen chemical tracer) increased on rainy sampling periods, especially during severe thunderstorms, and peaked when a tornado struck nearby. Submicron fluorescent particles, measured by single-particle fluorescence spectroscopy, were also enhanced during rain events, particularly thunderstorms in agreement with the chemical tracer measurements. PM2.5 sucrose (a pollen chemical tracer) concentrations were higher in early spring when nighttime temperatures were closer to freezing, while fructose concentrations were higher in late spring with warmer temperatures, consistent with chemical tracers being sensitive to seasonal temperature influences. The first co-located measurements of fructose and Bet v 1 (birch pollen allergen), indicated that SPP ranged in diameter from <0.25 to 2.5 µm during rainy sampling periods and that allergens and carbohydrates exhibited distinct size distributions. Meanwhile, mannitol (a fungal spore tracer) peaked on warm, dry days following rain and was primarily in supermicron particles (>1.0 µm), which is consistent with intact fungal spore diameters (1-30 µm). Bacterial endotoxins in PM also increased during extreme weather events, primarily in supermicron particles. While the concentrations of fructose, mannitol, and endotoxin all increased in PM2.5 µm during thunderstorms, the greatest relative increase in concentration was observed for fructose. Together, these observations suggest that SPP containing starch granules and allergens (Bet v 1) were released during rainy sampling periods. This study advances the use of chemical tracers to track SPP and other bioaerosols in the atmosphere, by providing new insight to their size distribution and response to extreme weather conditions.

Plastic Burning Impacts on Atmospheric Fine Particulate Matter at Urban and Rural Sites in the USA and Bangladesh.

To better understand the impact of plastic burning on atmospheric fine particulate matter (PM2.5), we evaluated two methods for the quantification of 1,3,5-triphenylbenzene (TPB), a molecular tracer of plastic burning. Compared to traditional solvent-extraction gas chromatography mass spectrometry (GCMS) techniques, thermal-desorption (TD) GCMS provided higher throughput, lower limits of detection, more precise spike recoveries, a wider linear quantification range, and reduced solvent use. This method enabled quantification of TPB in fine particulate matter (PM2.5) samples collected at rural and urban sites in the USA and Bangladesh. These analyses demonstrated a measurable impact of plastic burning at 5 of the 6 study locations, with the largest absolute and relative TPB concentrations occurring in Dhaka, Bangladesh, where plastic burning is expected to be a significant source of PM2.5. Background-level contributions of plastic burning in the USA were estimated to be 0.004-0.03 µg m-3 of PM2.5 mass. Across the four sites in the USA, the lower estimate of plastic burning contributions to PM2.5 ranged 0.04-0.8%, while the median estimate ranged 0.3-3% (save for Atlanta, Georgia, in the wintertime at 2-7%). The results demonstrate a consistent presence of plastic burning emissions in ambient PM2.5 across urban and rural sites in the USA, with a relatively small impact in comparison to other anthropogenic combustion sources in most cases. Much higher TPB concentrations were observed in Dhaka, with estimated plastic burning impacts on PM2.5 ranging from a lower estimate of 0.3-1.8 µg m-3 (0.6-2% of PM2.5) and the median estimate ranging 2-35 µg m-3 (5-15% of PM2.5). The methodological advances and new measurements presented herein help to assess the air quality impacts of burning plastic more broadly.

Veterinarians' use of the Talking Physical Exam as a communication tool.

OBJECTIVE: To describe veterinarians' communication of the companion animal physical exam (CAPE) to veterinary clients and to identify factors associated with the number of physical exam components communicated by veterinarians to clients. SAMPLE: 376 video-recorded veterinarian-client-patient interactions, involving 60 veterinarians. PROCEDURES: 18 CAPE components were studied in relation to veterinarians' use of 7 communication-related parameters. A mixed linear regression model was used to assess veterinarian, patient, and appointment factors associated with the number of components conveyed by a veterinarian. RESULTS: Veterinarians conveyed 1,566 of 2,794 (56.1%) of the components that they examined to clients, as having been examined. Of those components that were examined and conveyed by veterinarians, the impact of the finding was communicated for 496 of 1,566 (31.7%) of the components. Visual aids and take-home literature were each used in relation to an examined component during 15 of the 376 interactions (4%). A significant association was found between number of CAPE components conveyed and gender of the veterinarian (females conveyed 1.31 more), as well as the type of appointment (2.57 more were conveyed in wellness appointments and 1.37 more in problem appointments, compared to rechecks). CLINICAL RELEVANCE: Findings identify an opportunity for veterinarians to further emphasize components of the CAPE, which may in turn increase clients' perceived value of the CAPE due to understanding the benefits for their pet. This may be accomplished with the Talking Physical Exam, in which veterinarians discuss CAPE components findings with clients in real time, and the relevance of the findings to the patient's health.

Twenty-five components of a baseline, best-practice companion animal physical exam established by a panel of experts.

OBJECTIVE: To establish the components of a best-practice, baseline companion animal physical exam (CAPE). SAMPLE: 25 small animal veterinary internists and 20 small animal primary care veterinarians, all teaching the CAPE at veterinary colleges in the US, Canada, and Australia. PROCEDURES: Using the Delphi Method of Consensus, 3 rounds of online questionnaires were sent to participants. The first round included demographic questions, questions about teaching the physical exam, and an open-ended question allowing participants to record details of how they conduct a CAPE. In the second round, participants were asked to rate components of the CAPE, which were derived from round 1, as "always examine," "only examine as needed," or "undecided." Following round 2, any component not reaching 90% consensus (set a priori) for the response "always examine" was put forth in round 3, with a summary of comments from the round 2 participants for each remaining component. RESULTS: 35 components of a baseline CAPE were identified from round 1. The 25 components that reached 90% consensus by the end of round 3 were checking the oral cavity, nose, eyes, ears, heart, pulse rate, pulse quality, pulse synchrony, lungs, respiratory rate, lymph nodes, abdomen, weight, body condition score, mucous membranes, capillary refill time, general assessment, masses, haircoat, skin, hydration, penis and testicles or vulva, neck, limbs, and, in cats only, thyroid glands. CLINICAL RELEVANCE: The findings establish an expert panel's consensus on 25 components of a baseline, best-practice CAPE that can be used to help inform veterinary curricula, future research, and the practice of veterinarians.

Use of health parameter trends to communicate pet health information in companion animal practice: A mixed methods analysis.

BACKGROUND: Reviewing patient health parameter trends can strengthen veterinarian-client-patient relationships. The objective of this study is to identify characteristics associated with veterinarians' communication of health parameter trends to companion animal clients. METHODS: Using a sequential exploratory mixed methods design, independent pet owner (n = 27) and veterinarian (n = 24) focus groups were conducted and analysed via content analysis to assess perceptions of how health parameter trends are communicated by veterinarians. Subsequently, a quantitative assessment of video recorded veterinary appointments (n = 917) compared characteristics identified in focus groups with health parameter trend discussions in practice. A mixed logistic model was used to assess characteristics associated with the occurrence of weight trend discussions. RESULTS: Fifteen characteristics relating to veterinarians' use of health parameter trends were identified across focus groups. Veterinarians discussed 77 health parameter trends in relation to bodyweight (57/77), blood work (15/77) and other health parameters (5/77), within 73 (73/917) appointments. The odds of a weight trend discussion were higher if the veterinarian identified the pet as overweight or obese compared to an ideal bodyweight (odds ratio (OR) = 2.17; 95% confidence interval (CI) = 1.15-4.09; p = 0.016). CONCLUSION: Mention of a health parameter trend was uncommon and rarely included use of visual aids. Health parameter trends related to bodyweight were discussed reactively, rather than proactively.

Technology-enhanced weight-loss program in multiple-cat households: a randomized controlled trial.

OBJECTIVES: The objectives of this study were to determine whether a technology-enhanced weight-loss program, using a home pet health technology ecosystem, is an effective tool in feline weight-loss management in multiple-cat households and to evaluate its impact on cat behavior. METHODS: The study was a prospective parallel unmasked block-randomized controlled trial comparing two weight loss intervention groups: (1) traditional group with dietary restriction alone (n = 9); (2) technology group that used dietary restriction, digital scales, smart feeders, activity monitors and pet treat cameras (n = 6). A 12-week weight-loss program of client-owned indoor-only two- or three-cat households with at least one overweight cat was conducted in Canada and the USA. Owner impressions of the technology, weight loss rates, smart feeder data, activity monitor data and health-related quality of life (HRQoL) were assessed. RESULTS: The study was completed by 9/15 traditional group and 6/10 technology group cats. Dropouts were mainly due to owner issues unrelated to the study. The pet health technology ecosystem received favorable reviews (six responders). Smart feeders and home scales were perceived as valuable additions, while activity monitors and pet treat cameras were valued lower. The average weekly weight-loss rate (percent loss of initial body weight) was higher (P = 0.036) in the technology group (0.694%) than in the traditional group (0.175%). Although not associated with weight-loss rates, technology group cats trended toward grazing feeding patterns and decreased daily activity counts, while HRQoL increased, on average, for all cats. CONCLUSIONS AND RELEVANCE: This introductory investigation suggests that a technology-enhanced weight-loss program would be accepted by cat owners and may deliver advantageous outcomes in multiple-cat households, providing an effective and practical tool in feline weight-loss strategies that will continue to evolve as new technologies become available. It also illustrates the potential value of data gathered from home monitoring devices and digital diaries, providing deeper insights into pet behavior.

Companion animal veterinarians' and veterinary clients' perceptions of information exchanged while communicating about blood tests.

BACKGROUND: Blood tests play a vital role in veterinary medicine, as they enable veterinarians to make decisions about their patients' medical care and provide opportunities to engage clients in veterinary care. The objective of this study was to explore perspectives of veterinary clients and veterinarians on current reporting practices for blood tests ordered in companion animal practice. The type of information communicated and client information seeking behaviours were examined. METHODS: Two online surveys were distributed using snowball sampling: one targeting veterinary clients and one targeting veterinarians. RESULTS: In total, 529 veterinary client and 416 veterinarian surveys were included in analyses. Significant differences were found between what blood test information veterinarian respondents felt they provided clients and what client respondents perceived they received with regard to their pet's blood tests. Almost 60% of clients somewhat or strongly agreed that they search the Internet if they do not understand why a test was ordered or what the results mean. Half of clients reported that they never receive a written report of their pet's blood work, 81% of whom were interested in receiving a copy. CONCLUSION: Results of this research demonstrate opportunities to improve veterinarians' and clients' communication about blood tests.

Isolating Conformers to Assess Dynamics of Peptidic Catalysts Using Computationally Designed Macrocyclic Peptides.

Studying the relationship between catalyst conformational dynamics and selectivity in an asymmetric reaction is a challenge. In this study, cyclic peptides were computationally designed to stabilize different ground state conformations of a highly effective, flexible tetrapeptide catalyst for the atroposelective bromination of N-aryl quinazolinones. Through a combination of computational and experimental techniques, we have determined that dynamic movement of the lead catalyst plays a crucial role in achieving high enantioselectivity in the reaction of study. This approach may also serve as a valuable method for investigating the mechanism of other peptide-catalyzed transformations.

Optimization of Triarylpyridinone Inhibitors of the Main Protease of SARS-CoV-2 to Low-Nanomolar Antiviral Potency.

Non-covalent inhibitors of the main protease (Mpro) of SARS-CoV-2 having a pyridinone core were previously reported with IC50 values as low as 0.018 µM for inhibition of enzymatic activity and EC50 values as low as 0.8 µM for inhibition of viral replication in Vero E6 cells. The series has now been further advanced by consideration of placement of substituted five-membered-ring heterocycles in the S4 pocket of Mpro and N-methylation of a uracil ring. Free energy perturbation calculations provided guidance on the choice of the heterocycles, and protein crystallography confirmed the desired S4 placement. Here we report inhibitors with EC50 values as low as 0.080 µM, while remdesivir yields values of 0.5-2 µM in side-by-side testing with infectious SARS-CoV-2. A key factor in the improvement is enhanced cell permeability, as reflected in PAMPA measurements. Compounds 19 and 21 are particularly promising as potential therapies for COVID-19, featuring IC50 values of 0.044-0.061 µM, EC50 values of ca. 0.1 µM, good aqueous solubility, and no cytotoxicity.

Evaluating shared decision-making between companion animal veterinarians and their clients using the Observer OPTION5 instrument.

BACKGROUND: Communication practices used by veterinarians can impact client's involvement in decision-making. The objective of this study was to evaluate the level of client involvement in veterinary care decisions and factors impacting client involvement. METHODS: A random sample of practising companion animal veterinarians and a convenience sample of pet owners were recruited. Each consultation was audio-video recorded and analyzed using the Observer OPTION5 instrument, adapted from human medicine, to assess veterinarians' level of shared decision-making. A mixed linear model was used to assess statistical associations between veterinarian, client and appointment-level factors and OPTION5 scores. RESULTS: Sixty veterinarians and 909 of their clients were audio-video recorded during a consultation, of which 717 interactions included a decision identified for analysis using the OPTION5 instrument. Elements consistent with shared decision-making were uncommon, with a mean OPTION5 score of 22.6 (median = 20.0; sd = 13.05; range = 0-75) out of 100. OPTION5 scores were positively associated with the length of the appointment and negatively associated with the veterinarian's years in practice when controlling for statistical interaction between client income and appointment type. CONCLUSION: Findings suggest an opportunity exists for veterinarians to incorporate more client involvement through increased use of shared decisionmaking behaviours during veterinary consultations.

Structure-guided design of a perampanel-derived pharmacophore targeting the SARS-CoV-2 main protease.

There is a clinical need for direct-acting antivirals targeting SARS-CoV-2, the coronavirus responsible for the COVID-19 pandemic, to complement current therapeutic strategies. The main protease (Mpro) is an attractive target for antiviral therapy. However, the vast majority of protease inhibitors described thus far are peptidomimetic and bind to the active-site cysteine via a covalent adduct, which is generally pharmacokinetically unfavorable. We have reported the optimization of an existing FDA-approved chemical scaffold, perampanel, to bind to and inhibit Mpro noncovalently with IC50s in the low-nanomolar range and EC50s in the low-micromolar range. Here, we present nine crystal structures of Mpro bound to a series of perampanel analogs, providing detailed structural insights into their mechanism of action and structure-activity relationship. These insights further reveal strategies for pursuing rational inhibitor design efforts in the context of considerable active-site flexibility and potential resistance mechanisms.

Potent Noncovalent Inhibitors of the Main Protease of SARS-CoV-2 from Molecular Sculpting of the Drug Perampanel Guided by Free Energy Perturbation Calculations.

Starting from our previous finding of 14 known drugs as inhibitors of the main protease (Mpro) of SARS-CoV-2, the virus responsible for COVID-19, we have redesigned the weak hit perampanel to yield multiple noncovalent, nonpeptidic inhibitors with ca. 20 nM IC50 values in a kinetic assay. Free-energy perturbation (FEP) calculations for Mpro-ligand complexes provided valuable guidance on beneficial modifications that rapidly delivered the potent analogues. The design efforts were confirmed and augmented by determination of high-resolution X-ray crystal structures for five analogues bound to Mpro. Results of cell-based antiviral assays further demonstrated the potential of the compounds for treatment of COVID-19. In addition to the possible therapeutic significance, the work clearly demonstrates the power of computational chemistry for drug discovery, especially FEP-guided lead optimization.