Sage-grouse Habitat in Utah. A Guide for Landowners and Managers

This publication addressing sage-grouse habitat in Utah noting that the loss and fragmentation of sagebrush landscapes in the West have caused the decline of sage-grouse populations

Photoenzymatic Hydrogenation of Heteroaromatic Olefins using ‘Ene’-Reductases with Photoredox Catalysts

Flavin‐dependent ‘ene’‐reductases (EREDs) are highly selective catalysts for the asymmetric reduction of activated alkenes. This function is, however, limited to enones, enoates, and nitroalkenes using the native hydride transfer mechanism. Here we demonstrate that EREDs can reduce vinyl pyridines when irradiated with visible light in the presence of a photoredox catalyst. Experimental evidence suggests the reaction proceeds via a radical mechanism where the vinyl pyridine is reduced to the corresponding neutral benzylic radical in solution. DFT calculations reveal this radical to be “dynamically stable”, suggesting it is sufficiently long lived to diffuse into the enzyme active site for stereoselective hydrogen atom transfer. This reduction mechanism is distinct from the native one, highlighting the opportunity to expand the synthetic capabilities of existing enzyme platforms by exploiting new mechanistic paradigms

Airway resistance at maximum inhalation as a marker of asthma and airway hyperresponsiveness

<p>Abstract</p> <p>Background</p> <p>Asthmatics exhibit reduced airway dilation at maximal inspiration, likely due to structural differences in airway walls and/or functional differences in airway smooth muscle, factors that may also increase airway responsiveness to bronchoconstricting stimuli. The goal of this study was to test the hypothesis that the minimal airway resistance achievable during a maximal inspiration (R_min) is abnormally elevated in subjects with airway hyperresponsiveness.</p> <p>Methods</p> <p>The R_minwas measured in 34 nonasthmatic and 35 asthmatic subjects using forced oscillations at 8 Hz. R_minand spirometric indices were measured before and after bronchodilation (albuterol) and bronchoconstriction (methacholine). A preliminary study of 84 healthy subjects first established height dependence of baseline R_minvalues.</p> <p>Results</p> <p>Asthmatics had a higher baseline R_min% predicted than nonasthmatic subjects (134 ± 33 vs. 109 ± 19 % predicted, p = 0.0004). Sensitivity-specificity analysis using receiver operating characteristic curves indicated that baseline R_minwas able to identify subjects with airway hyperresponsiveness (PC₂₀< 16 mg/mL) better than most spirometric indices (Area under curve = 0.85, 0.78, and 0.87 for R_min% predicted, FEV₁% predicted, and FEF_25-75% predicted, respectively). Also, 80% of the subjects with baseline R_min< 100% predicted did not have airway hyperresponsiveness while 100% of subjects with R_min> 145% predicted had hyperresponsive airways, regardless of clinical classification as asthmatic or nonasthmatic.</p> <p>Conclusions</p> <p>These findings suggest that baseline R_min, a measurement that is easier to perform than spirometry, performs as well as or better than standard spirometric indices in distinguishing subjects with airway hyperresponsiveness from those without hyperresponsive airways. The relationship of baseline R_minto asthma and airway hyperresponsiveness likely reflects a causal relation between conditions that stiffen airway walls and hyperresponsiveness. In conjunction with symptom history, R_mincould provide a clinically useful tool for assessing asthma and monitoring response to treatment.</p