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Calls have been made to discontinue the routine use of race and ethnicity in medicine. Specific to respiratory medicine, the use of race- and ethnicity-specific reference equations for the interpretation of pulmonary function test (PFT) results has been questioned. Three key questions were addressed: (1) What is the current evidence supporting the use of race- and ethnicity-specific reference equations for the interpretation of PFTs? (2) What are the potential clinical implications of the use or nonuse of race and ethnicity in interpreting PFT results? and (3) What research gaps and questions must be addressed and answered to understand better the effect of race and ethnicity on PFT results interpretation and potential clinical and occupational health implications? A joint multisociety (American College of Chest Physicians, American Association for Respiratory Care, American Thoracic Society, and Canadian Thoracic Society) expert panel was formed to undertake a comprehensive evidence review and to develop a statement with recommendations to address the research questions. Several assumptions and gaps, both in the published literature and in our evolving understanding of lung health, were identified. It seems that many past perceptions and practices regarding the effect of race and ethnicity on PFT results interpretation are based on limited scientific evidence and measures that lack reliability. A need exists for more and better research that will inform our field about these many uncertainties and will serve as a foundation for future recommendations in this area. The identified shortcomings should not be discounted or dismissed because they may enable flawed conclusions, unintended consequences, or both. Addressing the identified research gaps and needs would allow a better—a more informed—understanding of the effects of race and ethnicity on PFT results interpretation. [ABSTRACT FROM AUTHOR]

Higher education institutions (HEIs) play a critical role in creating and distributing the knowledge required to tackle the complex global challenges faced by society today. This role is frequently linked with the concept of the internationalization of higher education, but this concept in practice is also subject to criticism. This article argues that integrating the United Nations (UN) sustainable development goals (SDGs) into the teaching and learning functions, partnerships, research, and discovery functions of institutions has the potential to transform institutions and improve society through internationalization. In this article, the ideological and practical intersections of internationalization and the SDGs are discussed. Examples of initiatives around the world that have shaped societal discourse through the lens of internationalization and sustainable development are reviewed. The authors posit that integration of both concepts would enable HEIs to rise up to the global challenge of creating a better world for all. [ABSTRACT FROM AUTHOR]

Antecedentes: la extensión rural tiene sus inicios desde los principios del siglo XX como actividad complementaria de la enseñanza agropecuaria. Objetivo: transmitir conocimiento sobre el manejo adecuado de la lombricultura mediante la extensión rural usando herramientas como las intervenciones, siendo estas visitas a predio a pequeños y medianos productores. Métodos: a través de intervenciones extensionistas se logra llegar a esta comunidad que se caracteriza por dedicarse a los cultivos convirtiéndola en el lugar adecuado para llevar la lombricultura como instrumento de producción‚ se usaron herramientas extensionistas como la visita a predio y la demostración de método para desarrollar un plan de trabajo con nueve productores‚ los cuales fueron capacitados a cerca del manejo de la lombriz roja californiana para que pudieran llevar a cabo un adecuado proceso con sus lombrisarios; con el fin de mantener comunicación constante y poder atender de manera oportuna cualquier inquietud que pudiera presentarse se implementaron herramientas tecnológicas como un grupo de WhatsApp y un blog creado para brindar información al cual pudieran acudir los productores constantemente. Resultados: al cabo de cuatro meses de un arduo trabajo se logró obtener un fertilizante orgánico en diferentes presentaciones: humus sólido‚ humus líquido y lixiviado‚ con la finalidad de reducir el uso de químicos‚ reduciendo costos de producción e incluso generando ingresos con la venta de los productos‚ respecto a lo anterior cabe resaltar que se están generando alimentos de calidad sin agroquímicos tanto para los animales como para el hombre y de cierta manera también aportando a la reducción de gases de efecto invernadero generado tanto por los fertilizantes químicos como por los residuos fecales de los rumiantes principalmente. Conclusiones: se logró crear un cambio en los productores de la comunidad mediante la facilitación de la técnica de la lombricultura generando oportunidades para mejorar su calidad de vida de una manera ecosostenible. [ABSTRACT FROM AUTHOR]

Purpose: To understand the role of case complexity in the learning curve for robotic colorectal surgery.Materials and Methods: Sixty-two patients who underwent robot-assisted colorectal surgery were retrospectively reviewed. Each case was assigned a category of complexity ranging from I to IV. Overall, groups and categories of segmental colectomy, rectopexy, and proctectomy for cancer were analyzed according to case volume. Forty-eight patients who underwent similar laparoscopic cases during the same period were also reviewed for comparison.Results: Level I complexity cases were identified in 30% of the first 15 cases compared to 3% after the first 15 cases (P < .01). Level IV complexity cases were identified in 10% of the first 15 cases and 34% after 15 cases (P = .03). Mean operative time for the overall group was 426 minutes (range 178-766, standard deviation [SD] = 152) in the first 15 cases and 373 minutes (range 190-593, SD = 109) after more than 15 cases (P = NS). Mean operative time for rectal cancer procedures decreased from 518 minutes (range 425-752, SD = 88) to 410 minutes (range 220-593, SD = 98) after 15 cases (P = .02). Mean operative time for rectopexy decreased from 361 minutes (range 276-520, SD = 85) to 258 minutes (range 215-318, SD = 34) after 15 cases (P = .03). Overall complications were reduced after 15 cases (6.3%) compared with the first 15 cases (27%) (P = .04). When comparing laparoscopic and open cases, laparoscopic cases were associated with a significant shorter operative time (P = < .00001) as well as overall cost (P = < .00001).Conclusion: Complex robotic colorectal surgery can be performed early in the experience, with reduced operative time. Overall complications are reduced after 15 robotic cases. This study shows that improvement in robotic surgery operating time and surgical outcomes occur along with application of the technology to more difficult cases, not as a function of choosing less complex cases. [ABSTRACT FROM AUTHOR]

We study the dielectric constantof lead sulfide quantum dot (QD)films as a function of the volume fraction of QDs by varying the QDsize and keeping the ligand constant. We create a reliable QD sizingcurve using small-angle X-ray scattering (SAXS), thin-film SAXS toextract a pair-distribution function for QD spacing, and a stacked-capacitorgeometry to measure the capacitance of the thin film. Our data supporta reduced dielectric constant in nanoparticles. [ABSTRACT FROM AUTHOR]

Abstract: We developed a 1D reactive-transport model for examining how tectonic and climatic parameters, namely uplift rate, water seepage velocity, and temperature, control chemical weathering and atmospheric CO2 consumption rates during regolith development. The model consists of mass-conservation equations describing how mineral and solute concentrations change temporally and spatially (vertically) during weathering of granite containing 30% plagioclase (An20) and up to 3% accessory calcite. The equations are coupled by volumetric weathering rates, which depend on mineral abundances, intrinsic dissolution rate constants, and surface areas as well as the departure of pore water from thermodynamic equilibrium. We numerically solve a non-steady-state, non-dimensional version of the model. By eliminating the need to prescribe regolith thickness, non-dimensionalization introduces two key scaling parameters that drive variations in the model results: the rock residence time (τr , the time for rock to travel upward through the model domain) and the water residence time (τw , the time for water to travel downward through the model domain). We use the model to examine fundamental properties of chemical weathering, especially reaction front propagation, with the primary aim of characterizing weathering regimes and identifying factors that maximize the dissolution of plagioclase because only silicate weathering regulates atmospheric CO2 levels over geological timescales. Weathering regimes are commonly classified as transport (or supply)-limited versus weathering (or kinetically)-limited, but as outgrowths of geomorphology, these terms primarily refer to the role of τr in regulating regolith thickness. Our findings suggest that the paradigm should be expanded to include kinetic controls determined by τw . Both regimes can experience far-from- and near-equilibrium mineral dissolution. However, transport-limited regimes generally have lower τw /τr ratios compared to kinetically-limited regimes. Under transport limitation, thick to thin reaction fronts propagate downward indefinitely yielding extensive mineral depletion, deeply weathered regolith, and high ratios of silicate-to-carbonate weathering. Under kinetic limitation, thin to non-existent reaction fronts evolve to steady-state yielding minimal mineral depletion, no regolith development, and low ratios of silicate-to-carbonate weathering. Kinetically-limited regimes typifying tectonically active mountain ranges have low long-term atmospheric CO2 consumption rates. Transport-limited regimes typifying tectonically stable cratons also have low long-term atmospheric CO2 consumption rates, but because much of the Earth's surface is transport-limited, we infer that such environments have the greatest impact on the global atmospheric CO2 consumption flux. The model output leads us to hypothesize that the maximum contribution should occur for extensive regions of silicate bedrock consolidated in warm, wet climates because the combination of tectonic stability, high temperatures, and rapid seepage velocities accelerates reaction front propagation, facilitates calcite depletion, and sustains deep regolith development over long timescales. Our findings point to the importance of internal climate feedbacks for stabilizing long-term atmospheric CO2 levels. [Copyright &y& Elsevier]

Abstract: This study presents new ignition delay data measured in a rapid compression machine over a wide range temperature, pressure and fuel/air ratio. This data is an extension of that measured previously (D. Darcy, C.J. Tobin, K. Yasunaga, J.M. Simmie, J. Würmel, T. Niass, O. Mathieu, S.S. Ahmed, C.K. Westbrook, H.J. Curran, Combust. Flame, 159 (2012) 2219–2232.) for the oxidation of n-propylbenzene in a high-pressure shock tube. The data was obtained for equivalence ratios of 0.29, 0.48, 0.96, and 1.92, at compressed gas pressures of 10, 30 and 50atm, and over the temperature range of 650–1000K. Experimental data was also obtained at 50atm for all equivalence ratios in our new heated high-pressure shock tube and this is also presented here. Comparisons between the data obtained in both the rapid compression machine and the shock tube facilities showed excellent agreement. A previously published chemical kinetic mechanism has been improved and a low-temperature reaction mechanism has been added to simulate ignition delay times at the lower temperature conditions of this study by adding the appropriate species and reactions including alkyl-peroxyl and hydroperoxy-alkyl radical chemistry. Special attention was given to isomerizations and elimination reactions involving the secondary benzylic site on n-propylbenzene to obtain good agreement with the present experimental results. In general, good agreement was obtained between the model and experiments and consistent trends were observed and these are discussed. [Copyright &y& Elsevier]

We demonstrated a technique to control the placement of 6 nm-diameter CdSe and 5 nm-diameter CdSe/CdZnS colloidal quantum dots (QDs) through electron-beam lithography. This QD-placement technique resulted in an average of three QDs in each cluster, and 87% of the templated sites were occupied by at least one QD. These QD clusters could be in close proximity to one another, with a minimum separation of 12 nm. Photoluminescence measurements of the fabricated QD clusters showed intermittent photoluminescence, which indicates that the QDs were optically active after the fabrication process. This optimized top-down lithographic process is a step towards the integration of individual QDs in optoelectronic and nano-optical systems. [ABSTRACT FROM AUTHOR]

The Steep Ramp Anaerobic Test (SRAT) was developed as a clinical test of anaerobic leg muscle function for use in determining anaerobic power and in prescribing high-intensity interval exercise in patients with chronic heart failure and Chronic Obstructive Pulmonary Disease (COPD); however, neither the test-retest reliability nor the physiological qualities of this test have been reported. We therefore, assessed test-retest reliability of the SRAT and the physiological characteristics associated with the test in patients with COPD. 11 COPD patients (mean FEV1 43% predicted) performed a cardiopulmonary exercise test (CPET) on Day 1, and an SRAT and a 30-second Wingate anaerobic test (WAT) on each of Days 2 and 3. The SRAT showed a high degree of test-retest reliability (ICC = 0.99; CV = 3.8%, and bias 4.5W, error -15.3-24.4W). Power output on the SRAT was 157W compared to 66Won the CPET and 231Won the WAT. Despite the differences in workload, patients exhibited similar metabolic and ventilatory responses between the three tests. Measures of ventilatory constraint correlated more strongly with the CPET than the WAT; however, physiological variables correlated more strongly with the WAT. The SRAT is a highly reliable test that better reflects physiological performance on a WAT power test despite a similar level of ventilatory constraint compared to CPET. [ABSTRACT FROM AUTHOR]

The article presents information on a study which has examined the effects of helium-hyperoxia on 6-min walking distance in COPD patients. It has been demonstrated by the study that COPD patients significantly increased the 6MWT distance while breathing helium-hyperoxia. It has been suggested by the study that clinical benefit would be obtained by administering helium-hyperoxia during exercise.

Study objectives: Validation of test-shortening procedures for the 2-min tidal breathing methacholine challenge method. Design: Retrospective chart review. Setting: Tertiary-care university clinical pulmonary function laboratory. Patients: One thousand subjects aged 10 to 85 years (mean ± SD, 44.5 ± 16.0 years), 44.5% male, referred for methacholine challenge. Intervention: Two-minute tidal breathing methacholine challenge was performed, with both physician and technician access to published test-shortening procedures. Measurements and results: There were 315 positive test results (provocative concentration of methacholine causing a 20% fall in FEV[sub 1] [PC[sub 20]] ≤ 8 mg/mL) and 685 negative test results. The subjects with positive test results were less likely to be male (39.1 vs 47.5%; p < 0.02) and had lower FEV[sub 1] (91.8 ± 14.9% predicted vs 97.2 ± 13.9% predicted; p < 0.001). The average starting PC[sub 20] was between 0.5 mg/mL and 1.0 mg/mL; the most common PC[sub 20] was 1 mg/mL (67%). There were 431 skipped concentrations in 380 subjects. The mean number of methacholine inhalations was 3.7 ± 1.1 (3.9 ± 0.1 for negative test results vs 3.3 ± 1.2 for positive test results; p < 0.001). Eighteen subjects had a ≥ 20% FEV[sub 1] fall on the first inhalation, and 11 subjects had a ≥ 20% FEV[sub 1] fall after a skipped concentration. In only one case (0.1%) an FEV[sub 1] fall ≥ 40% on the first concentration was reported, compared with no eases after a skipped concentration and seven cases with a ≥40% FEV[sub 1] fall after a routine doubling dose step-up. Conclusions: The 2-min tidal breathing methacholine test in clinical practice can be safely shortened to an average of less than four inhalations using starting concentrations based on FEV[sub 1], asthma medication, and clinical features, and by occasionally omitting concentrations. [ABSTRACT FROM AUTHOR]

Cognitive and physical limitations are common in individuals with chronic lung diseases, but their interactions with physical function and activities of daily living are not well characterized. Understanding these interactions and potential contributors may provide insights on disability and enable more tailored rehabilitation strategies. This review summarizes a 2-day meeting of patient partners, clinicians, researchers, and lung associations to discuss the interplay between cognitive and physical function in people with chronic lung diseases. This report covers four areas: (1) cognitive-physical limitations in patients with chronic lung diseases; (2) cognitive assessments; (3) strategies to optimize cognition and motor control; and (4) future research directions. Cognitive and physical impairments have multiple effects on quality of life and daily function. Meeting participants acknowledged the need for a standardized cognitive assessment to complement physical assessments in patients with chronic lung diseases. Dyspnea, fatigue, and age were recognized as important contributors to cognition that can affect motor control and daily physical function. Pulmonary rehabilitation was highlighted as a multidisciplinary strategy that may improve respiratory and limb motor control through neuroplasticity and has the potential to improve physical function and quality of life. There was consensus that cognitive function and the cognitive interference of dyspnea in people with chronic lung diseases contribute to motor control impairments that can negatively affect daily function, which may be improved with pulmonary rehabilitation. The meeting generated several key research questions related to cognitive-physical interactions in individuals with chronic lung diseases. [ABSTRACT FROM AUTHOR]

The method uses only a simple Ouchterlony gel plate, and consists of measuring the distance travelled by the specific precipitate of the protein under standardized conditions. A simple statistical technique is used to estimate the error. It was possible to discriminate between protein solutions differing in concentration by 10 per cent. No interference was found when a large amount of rat serum was mixed with the protein solution. [ABSTRACT FROM AUTHOR]

Patients with heart failure with reduced ejection fraction (HFrEF) have exaggerated sympathoexcitation and impaired peripheral vascular conductance. Evidence demonstrating consequent impaired functional sympatholysis is limited in HFrEF. This study aimed to determine the magnitude of reduced limb vascular conductance during sympathoexcitation and whether functional sympatholysis would abolish such reductions in HFrEF. Twenty patients with HFrEF and 22 age-matched controls performed the cold pressor test (CPT) [left foot 2-min in −0.5 (1)°C water] alone and with right handgrip exercise (EX + CPT). Right forearm vascular conductance (FVC), forearm blood flow (FBF), and mean arterial pressure (MAP) were measured. Patients with HFrEF had greater decreases in %ΔFVC and %ΔFBF during CPT (both P < 0.0001) but not EX + CPT (P = 0.449, P = 0.199) compared with controls, respectively. %ΔFVC and %ΔFBF decreased from CPT to EX + CPT in patients with HFrEF (both P < 0.0001) and controls (P = 0.018, P = 0.015), respectively. MAP increased during CPT and EX + CPT in both groups (all P < 0.0001). MAP was greater in controls than in patients with HFrEF during EX + CPT (P = 0.025) but not CPT (P = 0.209). In conclusion, acute sympathoexcitation caused exaggerated peripheral vasoconstriction and reduced peripheral blood flow in patients with HFrEF. Handgrip exercise abolished sympathoexcitatory-mediated peripheral vasoconstriction and normalized peripheral blood flow in patients with HFrEF. These novel data reveal intact functional sympatholysis in the upper limb and suggest that exercise-mediated, local control of blood flow is preserved when cardiac limitations that are cardinal to HFrEF are evaded with dynamic handgrip exercise. NEW & NOTEWORTHY: Patients with HFrEF demonstrate impaired peripheral blood flow regulation, evidenced by heightened peripheral vasoconstriction that reduces limb blood flow in response to physiological sympathoexcitation (cold pressor test). Despite evidence of exaggerated sympathetic vasoconstriction, patients with HFrEF demonstrate a normal hyperemic response to moderate-intensity handgrip exercise. Most importantly, acute, simultaneous handgrip exercise restores normal limb vasomotor control and vascular conductance during acute sympathoexcitation (cold pressor test), suggesting intact functional sympatholysis in patients with HFrEF. [ABSTRACT FROM AUTHOR]

Background: Saskatchewan has implemented care pathways for several common health conditions. To date, there has not been any cost-effectiveness evaluation of care pathways in the province. The objective of this study was to evaluate the real-world cost-effectiveness of a chronic obstructive pulmonary disease (COPD) care pathway program in Saskatchewan. Methods: Using patient-level administrative health data, we identified adults (35+ years) with COPD diagnosis recruited into the care pathway program in Regina between April 1, 2018, and March 31, 2019 (N = 759). The control group comprised adults (35+ years) with COPD who lived in Saskatoon during the same period (N = 759). The control group was matched to the intervention group using propensity scores. Costs were calculated at the patient level. The outcome measure was the number of days patients remained without experiencing COPD exacerbation within 1-year follow-up. Both manual and data-driven policy learning approaches were used to assess heterogeneity in the cost-effectiveness by patient demographic and disease characteristics. Bootstrapping was used to quantify uncertainty in the results. Results: In the overall sample, the estimates indicate that the COPD care pathway was not cost-effective using the willingness to pay (WTP) threshold values in the range of $1,000 and $5,000/exacerbation day averted. The manual subgroup analyses show the COPD care pathway was dominant among patients with comorbidities and among patients aged 65 years or younger at the WTP threshold of $2000/exacerbation day averted. Although similar profiles as those identified in the manual subgroup analyses were confirmed, the data-driven policy learning approach suggests more nuanced demographic and disease profiles that the care pathway would be most appropriate for. Conclusions: Both manual subgroup analysis and data-driven policy learning approach showed that the COPD care pathway consistently produced cost savings and better health outcomes among patients with comorbidities or among those relatively younger. The care pathway was not cost-effective in the entire sample. [ABSTRACT FROM AUTHOR]

Chronic obstructive pulmonary disease patient care must include confirming a diagnosis with postbronchodilator spirometry. Because of the clinical heterogeneity and the reality that airflow obstruction assessed by spirometry only partially reflects disease severity, a thorough clinical evaluation of the patient should include assessment of symptom burden and risk of exacerbations that permits the implementation of evidence-informed pharmacologic and nonpharmacologic interventions. This guideline provides recommendations from a comprehensive systematic review with a meta-analysis and expert-informed clinical remarks to optimize maintenance pharmacologic therapy for individuals with stable COPD, and a revised and practical treatment pathway based on new evidence since the 2019 update of the Canadian Thoracic Society (CTS) Guideline. The key clinical questions were developed using the Patients/Population (P), Intervention(s) (I), Comparison/Comparator (C), and Outcome (O) model for three questions that focuses on the outcomes of symptoms (dyspnea)/health status, acute exacerbations, and mortality. The evidence from this systematic review and meta-analysis leads to the recommendation that all symptomatic patients with spirometry-confirmed COPD should receive long-acting bronchodilator maintenance therapy. Those with moderate to severe dyspnea (modified Medical Research Council ≥ 2) and/or impaired health status (COPD Assessment Test ≥ 10) and a low risk of exacerbations should receive combination therapy with a long-acting muscarinic antagonist/long-acting ẞ2-agonist (LAMA/LABA). For those with a moderate/severe dyspnea and/or impaired health status and a high risk of exacerbations should be prescribed triple combination therapy (LAMA/LABA/inhaled corticosteroids) azithromycin, roflumilast or N-acetylcysteine is recommended for specific populations; a recommendation against the use of theophylline, maintenance systemic oral corticosteroids such as prednisone and inhaled corticosteroid monotherapy is made for all COPD patients. [ABSTRACT FROM AUTHOR]

The article discusses the release of the clinical practice guideline for chronic obstructive pulmonary disease(COPD) by the American College of Chest Physicians, European Respiratory Society, American Thoracic Society and the American College of Physicians (ACP). The guideline proposes that inhaled bronchodilators might be effectively use in COPD patient with respiratory symptoms. The guideline stresses the significance of pulmonary rehabilitation which should be regarded in symptomatic patient.

A letter to the editor is presented about an article on pulmonary physiology, which was published in an earlier issue of the periodical.

This study aimed to evaluate the real-world impacts of a chronic obstructive pulmonary disease (COPD) care pathway program on healthcare utilization and costs in Saskatchewan, Canada. A difference-in-differences evaluation of a real-life deployment of a COPD care pathway, using patient-level administrative health data in Saskatchewan, was conducted. The intervention group (n = 759) included adults (35+ years) with spirometry-confirmed COPD diagnosis recruited into the care pathway program in Regina between April 1, 2018 and March 31, 2019. The 2 control groups comprised adults (35+ years) with COPD who lived in Saskatoon during the same period (n = 759) or Regina between April 1, 2015 and March 31, 2016 (n = 759) who did not participate in the care pathway. Compared with the individuals in the Saskatoon control groups, individuals in the COPD care pathway group had shorter inpatient hospital length of stay (average treatment effect on the treated [ATT] −0.46, 95% CI −0.88 to −0.04) but a higher number of general practitioner visits (ATT 1.46, 95% CI 1.14 to 1.79) and specialist physician visits (ATT 0.84, 95% CI 0.61 to 1.07). Regarding healthcare costs, individuals in the care pathway group had higher COPD-related specialist visit costs (ATT $81.70, 95% CI $59.45 to $103.96) but lower COPD-related outpatient drug dispensation costs (ATT −$4.81, 95% CI −$9.34 to −$0.27). The care pathway reduced inpatient hospital length of stay, but increased general practitioner and specialist physician visits for COPD-related services within the first year of implementation. • This study is one of the few that examined the real-world impacts of care pathways on patients with chronic diseases in publicly funded healthcare systems such as Canada, where innovative healthcare interventions are constantly being tried and evidence is increasingly being needed to guide expansion or withdrawal of interventions. • The study provided important information on how care pathways affected healthcare use and costs in different ways across the healthcare continuum, spanning primary care to inpatient critical care sectors. • The findings are useful for guiding policymakers to make educated decisions regarding how to expand complex population-based healthcare interventions. [ABSTRACT FROM AUTHOR]

Individuals with COPD and preserved ratio impaired spirometry (PRISm) findings in clinical settings have an increased risk of cardiovascular disease (CVD). Do individuals with mild to moderate or worse COPD and PRISm findings in community settings have a higher prevalence and incidence of CVD compared with individuals with normal spirometry findings? Can CVD risk scores be improved when impaired spirometry is added? The analysis was embedded in the Canadian Cohort Obstructive Lung Disease (CanCOLD). Prevalence of CVD (ischemic heart disease [IHD] and heart failure [HF]) and their incidence over 6.3 years were compared between groups with impaired and normal spirometry findings using logistic regression and Cox models, respectively, adjusting for covariables. Discrimination of the pooled cohort equations (PCE) and Framingham risk score (FRS) in predicting CVD were assessed with and without impaired spirometry. Participants (n = 1,561) included 726 people with normal spirometry findings and 835 people with impaired spirometry findings (COPD Global Initiative for Chronic Obstructive Lung Disease [GOLD] stage 1 disease, n = 408; GOLD stage ≥ 2, n = 331; PRISm findings, n = 96). Rates of undiagnosed COPD were 84% in GOLD stage 1 and 58% in GOLD stage ≥ 2 groups. Prevalence of CVD (IHD or HF) was significantly higher among individuals with impaired spirometry findings and COPD compared with those with normal spirometry findings, with ORs of 1.66 (95% CI, 1.13-2.43; P =.01∗) (∗ indicates statistical significane with P <.05) and 1.55 (95% CI, 1.04-2.31; P =.033∗), respectively. Prevalence of CVD was significantly higher in participants having PRISm findings and COPD GOLD stage ≥ 2, but not GOLD stage 1. CVD incidence was significantly higher, with hazard ratios of 2.07 (95% CI, 1.10-3.91; P =.024∗) for the impaired spirometry group and 2.09 (95% CI, 1.10-3.98; P =.024∗) for the COPD group compared to individuals with normal spirometry findings. The difference was significantly higher among individuals with COPD GOLD stage ≥ 2, but not GOLD stage 1. The discrimination for predicting CVD was low and limited when impaired spirometry findings were added to either risk score. Individuals with impaired spirometry findings, especially those with moderate or worse COPD and PRISm findings, have increased comorbid CVD compared with their peers with normal spirometry findings, and having COPD increases the risk of CVD developing. [ABSTRACT FROM AUTHOR]

Responds to comments on an article regarding bronchial hyperresponsiveness to pharmacologic agents such as methacholine as a hallmark of asthma, published in the December 2001 issue of 'Chest.' Tidal breathing method as the acceptable method for methacholine; Methacholine challenge methods involving differences in nebulization, inhalation pattern and dose step-ups.

Colloidalquantum dot arrays with long organic ligands have better packing orderthan those with short ligands but are highly resistive, making low-biasconductance measurements impossible with conventional two-probe techniques.We use an integrated charge sensor to study transport in weakly coupledarrays in the low-bias regime, and we nanopattern the arrays to minimizepacking disorder. We present the temperature and field dependenceof the resistance for nanopatterned oleic-acid and n-butylamine-capped PbS arrays, measuring resistances as high as 1018Ω. We find that the conduction mechanism changes fromnearest neighbor hopping in oleic-acid-capped PbS dots to Mott’svariable range hopping in n-butylamine capped PbSdots. Our results can be understood in terms of a change in the interdotcoupling strength or a change in density of trap states and highlightthe importance of the capping ligand on charge transport through colloidalquantum dot arrays. [ABSTRACT FROM AUTHOR]

Ventricular arrhythmias are associated with neurological impairment and could represent a source of cerebral hypoperfusion. In the present study, data from healthy individuals (n = 11), patients with ischaemic heart disease (IHD; ejection fraction >40%; n = 9) and patients with heart failure with reduced ejection fraction (HFrEF; EF = 31 (5)%, n = 11), as well as data from swine surgeries, where spontaneous ventricular arrhythmias were observed during cerebrovascular examination (transcranial Doppler ultrasound in humans and laser Doppler in swine) were analysed retrospectively to investigate the effect of arrhythmia on cerebral microvascular haemodynamics. A subset of participants also completed the Montreal Cognitive Assessment (MoCA). Middle cerebral artery mean blood velocity (MCAVmean) decreased during premature ventricular contraction (PVC) in all groups, and data from swine indicate PVCs reduced cerebral microvascular perfusion. Overall MCAVmean was decreased in the HFrEF vs. control group. Further, %∆MCAVmean/%∆mean arterial pressure during the PVC was greater in the HFrEF vs. control group and was correlated with decreased MoCA scores. Subanalysis of HFrEF data revealed that during bigeminy MCAVmean decreased owing to reductions during irregular beats only. During non‐sustained ventricular tachycardia, MCAVmean decreased but recovered above baseline upon return to sinus rhythm. Also, haemodynamic perturbations during and following the PVC were greater in the brachial artery vs. the MCA. Therefore, ventricular arrhythmias decreased indices of cerebral perfusion irrespective of IHD or HFrEF. The relative magnitude of arrhythmia‐induced haemodynamic perturbations appears to be population specific and arrhythmia type and organ dependent. The cumulative burden of arrhythmia‐induced deficits may exacerbate existing cerebral hypoperfusion in HFrEF and contribute to neurological abnormalities in this population. Key points: Irregular heartbeats are often considered benign in isolation, but individuals who experience them frequently have a higher prevalence of cerebrovascular and/or cognitive associated disorders. How irregular heartbeats affect blood pressure and cerebral haemodynamics in healthy and cardiovascular disease patients, those with and without reduced ejection fraction, remains unknown.Here it was found that in the absence of symptoms associated with irregular heartbeats, such as dizziness or hypotension, single, multiple non‐sustained and sustained irregular heartbeats influence cerebral haemodynamics in a population‐specific, arrhythmia‐type and organ‐dependent manner.Relative deficits in the index of cerebral blood flow normalized to relative deficits in blood pressure were greatest in patients with heart failure with reduced ejection and inversely related with cognitive performance.Chronic arrhythmias may exacerbate existing cerebral hypoperfusion in heart failure with reduced ejection fraction, thereby providing a mechanistic link between otherwise benign irregular heartbeats and cognitive dysfunction, independent of embolism. [ABSTRACT FROM AUTHOR]

The cardiopulmonary exercise test (CPET) is an important physiological investigation that can aid clinicians in their evaluation of exercise intolerance and dyspnea. Maximal oxygen consumption (V...O2max ) is the gold-standard measure of aerobic fitnessand is determined by the variables that define oxygen delivery in the Fick equation (V...O2 = cardiac output × arterial-venous O2 content difference). In healthy subjects, of the variables involved in oxygen delivery, it is the limitations of the cardiovascular system that are most responsible for limiting exercise, as ventilation and gas exchange are sufficient to maintain arterial O2 content up topeak exercise. Patients with lung disease can develop a pulmonary limitation to exercisewhich can contribute to exercise intolerance and dyspnea. In these patients, ventilation may be insufficient for metabolic demand, as demonstrated by an inadequate breathing reserve, expiratory flow limitation, dynamic hyperinflation, and/or retention of arterial CO2. Lung disease patients can also develop gas exchange impairments with exercise as demonstrated by an increased alveolar-to-arterial O2 pressure difference. CPET testing data, when combined with other clinical/investigation studies, can provide the clinician with an objective method to evaluate cardiopulmonary physiology and determination of exercise intolerance. [ABSTRACT FROM AUTHOR]

Background: Methacholine-induced bronchoconstriction is associated with significant hypoxemia, which can be assessed noninvasively by transcutaneous oxygen tension and pulse oximetry. Objectives: To assess the value of the monitoring of finger pulse oximetry during routine methacholine challenges in a clinical pulmonary function laboratory with regard to both safety and the possibility that a significant fall in oxygen saturation as measured by pulse oximetry (Spo[sub 2]) might be a useful surrogate for determining the response to methacholine. Methods: Two hundred consecutive patients undergoing diagnostic methacholine challenges in the pulmonary function laboratory of a tertiary-care, university-based referral hospital were studied. Methacholine challenges were performed by the standardized 2-min tidal breathing technique, and the ΔFEV[sub 1] was calculated from the lowest postsaline solution inhalation to the lowest postmethacholine inhalation value. Spo[sub 2] was measured immediately prior to each spirogram, and the ΔSpo[sub 2] was measured from the lowest postsaline solution inhalation value to the lowest postmethacholine inhalation value. We examined the data for safety (ie, any Spo[sub 2] value <90). Based on previous reports, we used a ΔSpo[sub 2] of ≥3 as significant and looked at the sensitivity, specificity, and positive and negative predictive values for ΔSpo[sub 2] ≥ 3 vis-à-vis a fall in FEV[sub 1] of ≥15%. Results: There were 119 nonresponders (ΔFEV[sub 1], <15%) and 81 responders. The baseline FEV[sub 1] percent predicted was slightly but significantly lower in the responders (responders [±SD], 91.6 ± 15%; nonresponders, 96.4 ± 14%; p < 0.05). ΔSpo[sub 2] was 3.1 ± 1.6 in the responders and 1.6 ± 1.8 in the nonresponders (p < 0.001). There was a single recording in one patient of Spo[sub 2] < 90 (88). A ΔSpo[sub 2] ≥ 3 had a sensitivity of 68%, a specificity of 73%, a positive predictive value of 63%, and negative predictive value of 77% for a fall in FEV[sub 1] ≥ 15%. Conclusions: Pulse oximetry is not routinely useful for safety monitoring during methacholine challenge. ΔSpo[sub 2] is not helpful in predicting a positive spirometric response to methacholine. However, the negative predictive value is adequate to allow the ΔSpo[sub 2] to be used as an adjunct in assessing a negative result of a methacholine test in patients who have difficulty performing spirometry. [ABSTRACT FROM AUTHOR]

Background: Physiologic and symptom responses at the ventilatory threshold (Tvent) during incremental cardiopulmonary exercise testing (CPET) can provide important prognostic information.Research Question: This study aimed to develop an updated normative reference set for physiologic and symptom responses at Tvent during cycle CPET (primary aim) and to evaluate previously recommended reference equations from a 1985 study for predicting Tvent responses (secondary aim).Study Design and Methods: Participants were adults 40 to 80 years of age who were free of clinically relevant disease from the Canadian Cohort Obstructive Lung Disease. Rate of oxygen consumption (V˙O2) at Tvent was identified by two independent raters; physiologic and symptom responses corresponding to V˙O2 at Tvent were identified by linear interpolation. Reference ranges (5th-95th percentiles) for responses at Tvent were calculated according to participant sex and age for 29 and eight variables, respectively. Prediction models were developed for nine variables (oxygen pulse, V˙O2, rate of CO2 production, minute ventilation, tidal volume, inspiratory capacity, end-inspiratory lung volume [in liters and as percentage of total lung capacity], and end-expiratory lung volume) using quantile regression, estimating the 5th (lower limit of normal), 50th (normal), and 95th (upper limit of normal) percentiles based on readily available participant characteristics. The two one-sided test of equivalence for paired samples evaluated the measured and 1985-predicted V˙O2 at Tvent for equivalence.Results: Reference ranges and equations were developed based on 96 participants (49% men) with a mean ± SD age of 63 ± 9 years. Mean V˙O2 at Tvent was 50% of measured V˙O2 peak; the normal range was 33% to 66%. The 1985 reference equations overpredicted V˙O2 at Tvent: mean difference in men, -0.17 L/min (95% CI, -0.25 to -0.09 L/min); mean difference in women, -0.19 L/min (95% CI, -0.27 to -0.12 L/min).Interpretation: A contemporary reference set of CPET responses at Tvent from Canadian adults 40 to 80 years of age is presented that differs from the previously recommended and often used reference set from 1985.Trial Registry: ClinicalTrials.gov; No.: NCT00920348; URL: www.clinicaltrials.gov. [ABSTRACT FROM AUTHOR]

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Background and objective: Lack of consensus on diagnosis of ACO limits our understanding of the impact, management and outcomes of ACO. The present observational study aims to describe the prevalence, clinical characteristics and course of individuals with ACO based on various definitions used in clinical practice. Methods: We included individuals with COPD from the prospective, multisite CanCOLD study and defined subjects with ACO using seven definitions commonly used in the literature. Results: Data including questionnaires, lung function and CT scans were analysed from 522 individuals with COPD who were randomly recruited from the population. Among them, 264 fulfilled at least one of the seven definitions of ACO. Prevalence of ACO varied from 3.8% to 31%. Regardless of the definition, individuals with ACO had worse outcomes (lung function and higher percentage of fast decliners, symptoms and exacerbations, health‐related quality of life and comorbidities) than the remaining patients with COPD. Conversely, patients with non‐ACO had higher emphysema and bronchiolitis scores. The three definitions that included atopy and/or physician diagnosis of asthma identified subjects who differed significantly from patients with COPD. The two ACO definitions with post‐bronchodilator reversibility were concordant with COPD and were the least stable, with less than 50% of the patients from each group maintaining reversibility over visits. Conclusion: Atopy and physician‐diagnosed asthma are more distinguishing characteristics to identify ACO. This finding needs to be validated using measures of airway inflammation and other specific biomarkers. [ABSTRACT FROM AUTHOR]

Background: COPD has a substantial burden seen in both patient quality of life and health-care costs. One method of minimizing this burden is the implementation of clinical pathways (CPWs). CPWs bring the best available evidence to a range of health-care professionals by adapting guidelines to a local context and detailing essential steps in care.Methods: A systematic review was conducted to address the following question: What are the effects of CPWs for COPD on patient-, professional-, and systems-level outcomes? The review used methods outlined by the Cochrane Collaboration. We included all studies that met our operational definition for CPWs and focused on COPD. All studies were evaluated for risk of bias, and all data regarding patient, professional, and systems outcomes were extracted.Results: The search strategy identified 497 potentially relevant titles. Of these, 13 studies were included in the review. These studies reported a total of 398 outcomes, with sufficient data for meta-analysis of five outcomes: complications, length of stay, mortality, readmissions, and quality of life. Results showed statistically significant reductions in complications, readmissions, and length of stay but did not show changes in mortality or quality of life.Conclusions: This systematic review reveals evidence to suggest that CPWs for COPD have the potential to reduce complications, readmissions, and length of stay without negatively influencing mortality or quality of life. However, quality of evidence was generally low. The authors therefore acknowledge that results should be interpreted with caution and note the need for additional research in this area. [ABSTRACT FROM AUTHOR]

Exercise intolerance is a hallmark feature in heart failure with preserved ejection fraction (HFpEF). Prior heavy exercise ("priming exercise") speeds pulmonary oxygen uptake (VO2p) kinetics in older adults through increased muscle oxygen delivery and/or alterations in mitochondrial metabolic activity. We tested the hypothesis that priming exercise would speed VO2p onkinetics in patients with HFpEF because of acute improvements in muscle oxygen delivery. Seven patients with HFpEF performed three bouts of two exercise transitions: MOD1, rest to 4-min moderateintensity cycling and MOD2, MOD1 preceded by heavy-intensity cycling. VO2p, heart rate (HR), total peripheral resistance (TPR), and vastus lateralis tissue oxygenation index (TOI; near-infrared spectroscopy) were measured, interpolated, time-aligned, and averaged. VO2p and HR were monoexponentially curve-fitted. TPR and TOI levels were analyzed as repeated measures between pretransition baseline, minimum value, and steady state. Significance was P < 0.05. Time constant (T; tau)VO2p (MOD1 49 ± 16 s) was significantly faster after priming (41 ± 14 s; P = 0.002), and the effective HR t was slower following priming (41 ± 27 vs. 51 ± 32 s; P = 0.025). TPR in both conditions decreased from baseline to minimum TPR (P < 0.001), increased from minimum to steady state (P = 0.041) but remained below baseline throughout (P = 0.001). Priming increased baseline (P = 0.003) and minimum TOI (P = 0.002) and decreased the TOI muscle deoxygenation overshoot (P = 0.041). Priming may speed the slowVO2p on-kinetics in HFpEF and increase muscle oxygen delivery (TOI) at the onset of and throughout exercise. Microvascular muscle oxygen delivery may limit exercise tolerance in HFpEF. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Mediterranean-type climate ecosystems experience significant variability in precipitation within and across years and may be characterized by periods of extreme drought followed by a brief, high-intensity precipitation pulse. Rapid root growth could be a key factor in effective utilization of precipitation pulses, leading to higher rates of seedling establishment. Changes in root growth rate are rarely studied, however, and patterns in seedling root traits are not well explored. We investigated the influence of an extreme postdrought precipitation event on seedlings that occur in southern California coastal sage scrub. METHODS: We measured root elongation rate, root tip appearance rate, new leaf appearance rate, and canopy growth rate on 18 mediterranean species from three growth forms. KEY RESULTS: Root elongation rate responded more strongly to the precipitation pulse than did root tip appearance rate and either metric of aboveground growth. The majority of species exhibited a significant change in root growth rate within 1 week of the pulse. Responses varied in rapidity and magnitude across species, however, and were not generally predictable based on growth form. CONCLUSIONS: While the majority of species exhibited shifts in belowground growth following the pulse, the direction and magnitude of these morphological responses were highly variable within growth form. Understanding the implications of these different response strategies for plant fitness is a crucial next step to forecasting community dynamics within ecosystems characterized by resource pulses. [ABSTRACT FROM AUTHOR]

Background: Chronic obstructive pulmonary disease (COPD) has substantial economic and human costs; it is expected to be the third leading cause of death worldwide by 2030. To minimize these costs high quality guidelines have been developed. However, guidelines alone rarely result in meaningful change. One method of integrating guidelines into practice is the use of clinical pathways (CPWs). CPWs bring available evidence to a range of healthcare professionals by detailing the essential steps in care and adapting guidelines to the local context.Methods/design: We are working with local stakeholders to develop CPWs for COPD with the aims of improving care while reducing utilization. The CPWs will employ several steps including: standardizing diagnostic training, unifying components of chronic disease care, coordinating education and reconditioning programs, and ensuring care uses best practices. Further, we have worked to identify evidence-informed implementation strategies which will be tailored to the local context. We will conduct a three-year research project using an interrupted time series (ITS) design in the form of a multiple baseline approach with control groups. The CPW will be implemented in two health regions (experimental groups) and two health regions will act as controls (control groups). The experimental and control groups will each contain an urban and rural health region. Primary outcomes for the study will be quality of care operationalized using hospital readmission rates and emergency department (ED) presentation rates. Secondary outcomes will be healthcare utilization and guideline adherence, operationalized using hospital admission rates, hospital length of stay and general practitioner (GP) visits. Results will be analyzed using segmented regression analysis.Discussion: Funding has been procured from multiple stakeholders. The project has been deemed exempt from ethics review as it is a quality improvement project. Intervention implementation is expected to begin in summer of 2017. This project is expected to improve quality of care and reduce healthcare utilization. In addition it will provide evidence on the effects of CPWs in both urban and rural settings. If the CPWs are found effective we will work with all stakeholders to implement similar CPWs in surrounding health regions.Trial Registration: Clinicaltrials.gov ( NCT03075709 ). Registered 8 March 2017. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Mediterranean-type climate ecosystems experience significant variability in precipitation within and across years and may be characterized by periods of extreme drought followed by a brief, high-intensity precipitation pulse. Rapid root growth could be a key factor in effective utilization of precipitation pulses, leading to higher rates of seedling establishment. Changes in root growth rate are rarely studied, however, and patterns in seedling root traits are not well explored. We investigated the influence of an extreme postdrought precipitation event on seedlings that occur in southern California coastal sage scrub. METHODS: We measured root elongation rate, root tip appearance rate, new leaf appearance rate, and canopy growth rate on 18 mediterranean species from three growth forms. KEY RESULTS: Root elongation rate responded more strongly to the precipitation pulse than did root tip appearance rate and either metric of aboveground growth. The majority of species exhibited a significant change in root growth rate within 1 week of the pulse. Responses varied in rapidity and magnitude across species, however, and were not generally predictable based on growth form. CONCLUSIONS: While the majority of species exhibited shifts in belowground growth following the pulse, the direction and magnitude of these morphological responses were highly variable within growth form. Understanding the implications of these different response strategies for plant fitness is a crucial next step to forecasting community dynamics within ecosystems characterized by resource pulses. [ABSTRACT FROM AUTHOR]