An Introduction to Processing, Fitting, and Interpreting Transient Absorption Data.

Transient absorption (TA) spectroscopy is a powerful time-resolved spectroscopic method used to track the evolution of excited-state processes through changes in the system's absorption spectrum. Early implementations of TA were confined to specialized laboratories, but the evolution of commercial turn-key systems has made the technique increasingly available to research groups across the world. Modern TA systems are capable of producing large datasets with high energetic and temporal resolution that are rich in photophysical information. However, processing, fitting, and interpreting TA spectra can be challenging due to the large number of excited-state features and instrumental artifacts. Many factors must be carefully considered when collecting, processing, and fitting TA data in order to reduce uncertainty over which model or set of fitting parameters best describes the data. The goal of data preparation and fitting is to reduce as many of these extraneous factors while preserving the data for analysis. In this method, beginners are provided with a protocol for processing and preparing TA data as well as a brief introduction to selected fitting procedures and models, specifically single wavelength fitting and global lifetime analysis. Commentary on a number of commonly encountered data preparation challenges and methods of addressing them is provided, followed by a discussion of the challenges and limitations of these simple fitting methods.

Controlling excited-state dynamics via protonation of naphthalene-based azo dyes.

Azo dyes are a class of photoactive dyes that constitute a major focus of chemical research due to their applications in numerous industrial functions. This work explores the impact of protonation on the photophysics of four naphthalene-based azo dyes. The pKa value of the dyes increases proportionally with decreasing Hammett parameter of p-phenyl substituents from 8.1 (R = -H, σ = 0) to 10.6 (R = -NMe2, σ = -0.83) in acetonitrile. Protonation of the dyes shuts down the steady-state photoisomerization observed in the unprotonated moieties. Fluorescence measurements reveal a lower quantum yield with more electron-donating p-phenyl substituents, with overall lower fluorescence quantum yields than the unprotonated dyes. Transient absorption spectroscopy reveals four excited-state lifetimes (<1 ps, ∼3 ps, ∼13 ps, and ∼200 ps) exhibiting faster excited-state dynamics than observed in the unprotonated forms (for 1-3: 0.7-1.5 ps, ∼3-4 ps, 20-40 ps, 20-300 min; for 4: 0.7 ps, 4.8 ps, 17.8 ps, 40 ps, 8 min). Time-dependent density functional theory (TDDFT) elucidates the reason for the loss of isomerization in the protonated dyes, revealing a significant change in the lowest excited state potential energy nature and landscape upon protonation. Protonation impedes relaxation along the typical rotational and inversion isomerization axes, locking the dyes into a trans-configuration that rapidly decays back to the ground state.

Longitudinal cardiac remodeling in collegiate American football players as assessed by echocardiography during their collegiate career.

BACKGROUND: Studies on the longitudinal effects of intense physical training on cardiac remodeling are limited, especially in American collegiate football players. HYPOTHESIS: College-level American football training will result in remodeling in a pattern consistent of a sport with moderate static and dynamic demands with increases in both wall and chamber sizes. METHODS: We studied 85 American collegiate football players who underwent transthoracic echocardiogram (TTE) for asymptomatic or mild COVID-19-related illness and compared the changes in echo dimensions to their preparticipation screening TTE. Pre- and posttraining variables were compared using a paired t-test for normally distributed variables. RESULTS: Mean age was 19 years ± 1 and 61% of athletes were Black. Mean follow-up between TTEs was 21 ± 13 months. There was an increase in left atrial volume index (26.4 ± 5.5 to 32.8 ± 8.4 mL/m2 , p < .001), LV end diastolic diameter (5.13 ± 0.4 to 5.27 ± 0.4 cm, p = .003), basal RV diameter (3.28 ± 0.7 to 3.83 ± 0.5 cm, p = <.001), LV mass index (86.7 ± 15.3 to 90.1 ± 15.3, p = .015), and aortic root diameter (3.1 ± 0.4 to 3.2 ± 0.3 cm, p = .03) from pre- to posttraining, with a slightly greater magnitude in athletes with >2 years of training. Presence of left atrial enlargement (≥35 mL/m2 ) increased from 2.9% to 29% pre- to postparticipation in athletes with >2 years training. No significant changes in wall thickness, diastolic function, or right ventricular systolic function were observed. CONCLUSION: American football players college-level training was associated with increases in left and right ventricular chamber sizes, left atrial size, and aortic root diameter.

Ultra-fast excited-state dynamics of substituted trans-naphthalene azo moieties.

In this work we untangle the ultrafast deactivation of high-energy excited states in four naphthalene-based azo dyes. Through systematic photophysical and computational study, we observed a structure-property relationship in which increasing the electron donating strength of the substituent leads to longer lived excited states in these organic dyes and faster thermal reversion from the cis to trans configuration. In particular, azo dyes 1-3 containing less electron donating substituents show three distinct excited-state lifetimes of ∼0.7-1.5 ps, ∼3-4 ps, and 20-40 ps whereas the most electron donating dimethyl amino substituted azo 4 shows excited-state lifetimes of 0.7 ps, 4.8 ps, 17.8 ps and 40 ps. While bulk photoisomerization of all four moieties is rapid, the cis to trans reversion lifetimes vary by a factor of 30 with τreversion decreasing from 276 min to 8 min with increasing electron donating strength of the substituent. In order to rationalize this change in photophysical behavior, we explored the excited-state potential energy surfaces and spin-orbit coupling constants for azo 1-4 through density functional theory. The increase in excited-state lifetime for 4 can be attributed to geometric and electronic degrees of freedom of the lowest energy singlet excited-state potential energy surface.

Elucidation of complex triplet excited state dynamics in Pd(II) biladiene tetrapyrroles.

Pd(II) biladienes have been developed over the last five years as non-aromatic oligotetrapyrrole complexes that support a rich triplet photochemistry. In this work, we have undertaken the first detailed photophysical interrogation of three homologous Pd(II) biladienes bearing different combinations of methyl- and phenyl-substituents on the frameworks' sp3-hybridized meso-carbon (i.e., the 10-position of the biladiene framework). These experiments have revealed unexpected excited-state dynamics that are dependent on the wavelength of light used to excite the biladiene. More specifically, transient absorption spectroscopy revealed that higher-energy excitation (λexc ∼ 350-500 nm) led to an additional lifetime (i.e., an extra photophysical process) compared to experiments carried out following excitation into the lowest-energy excited states (λexc = 550 nm). Each Pd(II) biladiene complex displayed an intersystem crossing lifetime on the order of tens of ps and a triplet lifetime of ∼20 µs, regardless of the excitation wavelength. However, when higher-energy light is used to excite the complexes, a new lifetime on the order of hundreds of ps is observed. The origin of the 'extra' lifetime observed upon higher energy excitation was revealed using density functional theory (DFT) and time-dependent DFT (TDDFT). These efforts demonstrated that excitation into higher-energy metal-mixed-charge-transfer excited states with high spin-orbit coupling to higher energy metal-mixed-charge-transfer triplet states leads to the additional excitation deactivation pathway. The results of this work demonstrate that Pd(II) biladienes support a unique triplet photochemistry that may be exploited for development of new photochemical schemes and applications.

Relationship between arm span to height ratio, aortic root diameter, and systolic blood pressure in collegiate athletes.

Study objective: Sudden cardiac death is the most common cause of non-traumatic death in collegiate athletes. Marfan syndrome poses a risk for sudden cardiac death secondary to aortic root dilation leading to aortic dissection or rupture. Arm span to height ratio (ASHR) > 1.05 has been proposed as a screening tool for Marfan syndrome in pre-participation examinations (PPE) for collegiate athletes but limited data exists on the association between ASHR and aortic root diameter (ARD). This study examines the relationship between ASHR and ARD and assesses for predictors of ARD. Design: Retrospective chart review. Setting: National Collegiate Athletic Association Division I University. Participants: 793 athletes across thirteen sports between 2012 and 2022 evaluated with PPE and screening echocardiogram. Interventions: Not applicable. Main outcome measures: (1) Relationships between ASHR, SBP, BSA, and ARD amongst all athletes as well as stratified by ASHR >1.05 or ≤1.05 using univariate analysis. (2) Predictors of ARD using multivariate analysis using linear regression. Results: 143 athletes (18 %) had ASHRs > 1.05. Athletes with ASHR > 1.05 had higher ARD (2.99 cm) than athletes with ASHR ≤ 1.05 (2.85 cm). Weak correlations were noted between ASHR, ARD, and SBP. Multivariate analysis showed that BSA, male sex, and participation in swimming were predictors of ARD. ASHR was not predictive of ARD in regression analysis. Conclusions: These findings showed a tendency towards higher ARD in athletes with ASHR >1.05 but this observation was not statistically significant in multivariate analysis.

Estimation of Right Atrial Pressure Using a Portable Handheld Ultrasound Device.

BACKGROUND: Handheld ultrasound devices are increasingly used by clinicians for their ease of use and portability. Their utility for estimating right atrial pressure (RAP) is poorly described. METHODS: This prospective study enrolled 50 consecutive patients presenting for outpatient right heart catheterization (RHC). A handheld ultrasound device was used to measure inferior vena cava size and collapsibility and estimate RAP to be 3, 8, or 15 mmHg according to American Society of Echocardiography recommendations for cardiac chamber quantification. Invasive pressure measurements were then performed using RHC. Spearman's correlation and linear regression analysis were used to evaluate the association between estimated RAP using ultrasound and invasive RAP. RESULTS: Fifty patients were enrolled (mean age 68 ± 8 years). Estimated RAP by ultrasound was significantly associated with invasive RAP (r 0.80; R2 0.63; 95% confidence interval, 0.61-0.96; P < .001). The correlation was stronger when RHC was indicated for evaluation of heart failure (r 0.88; P < .001) compared with other indications (r 0.69; P < .001). An estimated RAP of 3, 8, and 15 mmHg by ultrasound had a sensitivity and specificity of predicting an invasive RAP of 0-5, 6-10, and > 10 mmHg of 88% and 76%, 56% and 88%, and 81% and 97%, respectively, with overall accuracy of 80%, 76%, and 92%, respectively. Estimated RAP also correlated with invasive pulmonary capillary wedge pressure (r 0.64; R2 0.41; 95% confidence interval, 0.26-0.54; P < .001). CONCLUSIONS: Handheld ultrasonography is a useful tool that can accurately estimate RAP at the bedside.

Blood pressure characteristics of collegiate female athletes: A call for more focused attention on young women's health.

Background: There is a paucity of data describing the association between blood pressure (BP) and cardiac remodeling in female collegiate athletes. Methods: This retrospective cohort review describes the BP characteristics and echocardiographic features of female collegiate athletes during preparticipation evaluation. We evaluated data from 329 female athletes at two National Collegiate Athletic Association (NCAA) Division I universities who underwent preparticipation evaluation that included medical history, physical examination, 12-lead electrocardiography, and 2-dimensional transthoracic echocardiography. BP values were divided into categories of normal, elevated, stage 1 and stage 2 hypertension based on 2017 ACC/AHA Guidelines. Left ventricular mass index was calculated and indexed to body surface area and further classified into concentric remodeling, concentric hypertrophy, and eccentric hypertrophy. Results: Normal BP values were noted in 184 (56%) female athletes, 88 (26.7%) had elevated BP and 57 (17.3%) had BP values indicating stage 1 or 2 hypertension. The majority of participants were white (n = 136, 73.9%). There was significantly higher body surface area in female athletes with higher BP values: 1.85 ± 0.18 in the stage 1 and 2 hypertension range, 1.82 ± 0.18 in the elevated BP range versus 1.73 ± 0.16 in the normal BP range (p < 0.001). Conclusions: There was a trend toward higher incidence of concentric and eccentric hypertrophy in athletes with higher than normal BP, however no statistical significance was noted. Elevated BP values were frequent among female collegiate athletes, and there is evidence of cardiac remodeling associated with higher BP values.

Preparticipation Cardiac Evaluation Findings in a Cohort of Collegiate Female Athletes.

Knowledge of cardiovascular adaptations in athletes has predominantly focused on males, with limited data available on females who compromise a substantial percentage of all collegiate athletes. A multicenter retrospective cohort review of preparticipation cardiovascular screening data of 329 National Collegiate Athletic Association Division I female athletes was performed. This included physical exams, electrocardiograms, and echocardiograms. Female athletes in class IB sports had elevated systolic blood pressure (p = 0.01). For electrocardiograms, 7 (2%) had abnormal findings: 100% were white; 6 of 7 (86%) participated in IIC sports. Black athletes had longer PR intervals (p ≤ 0.001), whereas white athletes had longer QTc and QRS durations (p = 0.02 and 0.01, respectively). Athletes in IC and IIC sports had longer QTc intervals (p = 0.01). For echocardiographic parameters, no differences were noted based on race. However, significant differences were noted based on classification of sport: athletes in class IC sports had higher left-atrial volume indexes and E/A ratios. Athletes in class IB and IIC had increased left-ventricular wall thicknesses and aortic root dimensions. In conclusion, among one of the largest cohorts of collegiate female athlete preparticipation cardiac screening data to date, significant differences in various parameters based on classification of sport and race were observed. These categorizations should be considered when interpreting cardiovascular screening in female collegiate athletes to improve screening and guide future research.

Pulmonary hypertension in patients with interstitial pneumonia with autoimmune features.

Pulmonary hypertension in interstitial lung diseases is associated with increased mortality and hospitalizations and reduced exercise capacity. Interstitial pneumonia with autoimmune features (IPAF) is a recently described interstitial lung disease. The characteristics of pulmonary hypertension in IPAF patients are unknown. We sought to characterize patients with IPAF based on their echocardiographic probability of pulmonary hypertension and compare patients with and without pulmonary hypertension identified by right heart catheterization. We conducted a retrospective study of patients seen in the interstitial lung disease clinic from 2015 to 2018. Forty-seven patients with IPAF were identified. Patients were classified into low, intermediate and high echocardiographic pulmonary hypertension probabilities. A sub-group analysis of patients with pulmonary hypertension and without pulmonary hypertension (IPAF-PH vs. IPAF-no PH) identified by right heart catheterization was also performed. Linear regression analysis was performed to study the association between 6-min-walk-distance (6MWD) and pulmonary vascular resistance (PVR) while adjusting for age and body mass index. Right ventricular hypertrophy (>5 mm), right ventricular enlargement (>41 mm) and right ventricular systolic dysfunction defined as fractional area change% ≤35 was present in 76%, 24%, and 39% of patients, respectively. Pulmonary hypertension was identified in 12.7% of patients. IPAF-PH patients had higher mean pulmonary artery pressure and lower cardiac output compared to the IPAF-no PH group (34 mmHg vs. 19 mmHg, p = 0.002 and 4.0 vs. 5.7 L/min, p = 0.023, respectively). Lower 6MWD was associated with higher PVR on regression analysis (p = 0.002). Pulmonologists should be aware that a significant number of IPAF patients may develop pulmonary hypertension. Reduced 6MWD may suggest the presence of pulmonary hypertension in IPAF patients.

Predictors of ventricular pacing burden after permanent pacemaker implantation following transcatheter aortic valve replacement.

BACKGROUND: In the era of an expanding use of transcatheter aortic valve replacement (TAVR), conduction disturbances and the requirement for permanent pacemaker (PPM) implantation remains a clinical concern. HYPOTHESIS: Using a single-center experience, we sought to identify predictors of ventricular pacing burden after TAVR in patients who required PPM implantation. METHODS: We conducted a retrospective study of 359 consecutive patients with symptomatic severe aortic valve stenosis who underwent TAVR at our institution between September 2013 and July 2019. Thirty patients (8.4%) required a PPM within 30 days after TAVR. Pre and post-TAVR electrocardiograms, pre-TAVR echocardiograms and computed tomography (CT), TAVR procedural details and post-TAVR device interrogation records at 1, 3, and 6 months were reviewed. RESULTS: Mean percentage of ventricular pacing (VP%) at 1, 3, and 6 months was 58%, 59%, and 56% respectively. Using univariate logistic regression analysis, patients who had low VP% < 5% at 6 months were more likely to have a prosthesis/echocardiography-derived left ventricular outflow tract (LVOT) diameter ratio < 1.3 (OR 7.00, P-value .048), prosthesis/CT-derived aortic annulus diameter ratio < 1.02 (OR 7.11, P-value .047), post-TAVR new-onset LBBB (OR 16.80, P-value .019), time to PPM implantation greater than 2 days post-TAVR (OR 9.38, P-value .026) and pre-TAVR use of a beta blocker (OR 9.40, P-value .026). CONCLUSIONS: In patients who required a PPM implantation post-TAVR, a lower TAVR prosthesis/LVOT or aortic annulus diameter ratio, post-TAVR new-onset LBBB and later time of PPM implantation showed a trend toward predicting a low VP% at 6 months.

Utility of the Diamond-Forrester Classification in Stratifying Acute Chest Pain in an Academic Chest Pain Center.

BACKGROUND: Because the Diamond-Forrester (DF) model is predictive of obstructive coronary artery disease (CAD), it is often used to risk stratify acute chest pain patients. We sought to further evaluate the clinical utility of the DF model within a chest pain evaluation center. METHODS: Consecutive patients with chest pain and no known CAD or evidence of active ischemia were asked to participate in a prospective registry. Patients were classified based on cardiovascular risk factors, age, and DF classification. We compared data from the emergency department course, Duke Activity Status Index (DASI) and Seattle Angina Questionnaire (SAQ), hospitalization rates, and results of testing between patients with typical angina and all others. Multivariate logistic regression was also used to assess for predictors of CAD by computed tomography coronary angiography (CTCA) or positive exercise treadmill testing (ETT). RESULTS: Among 209 patients, 163 had atypical/noncardiac and 46 had typical chest pain. The SAQ and DASI scores were lower in the typical chest pain group (indicating more severe impairment), which were not statistically significantly different. There were no significant differences in risk factors or the results of CTCA, ETT, or cardiac catheterization. In the regression analysis, SAQ score, DASI score, and DF classification were not predictive of CAD by CTCA. Worsening angina frequency scores on the SAQ were marginally associated with positive ETT (OR, 1.04; P=0.04). CONCLUSION: In a contemporary low-risk acute chest pain population, typical angina, as defined by the DF classification, was not predictive of CAD or useful for identifying patients with higher symptom burden.

Evaluation of a statewide medical home program on children and young adults with asthma.

OBJECTIVE: Asthma, the most common chronic condition among children, accounts for significant healthcare utilization and impact on quality of life. Care coordination in a medical home is considered standard practice, but has not been rigorously evaluated. METHODS: We initiated this pilot study of children/young adults with asthma (n = 967), ages: birth to 24 years, receiving care from a subset of pediatric practices (n = 20) participating in the Pennsylvania Medical Home Initiative, Educating Practices in Community-Integrated Care (92 practices statewide). We hypothesized children and youth with asthma receiving care coordination in the context of a formal medical home program would experience favorable associations with healthcare utilization and quality of life measures. RESULTS: A total of 9240 care coordination encounters for this cohort of children/youth occurred over 100 days. The average length of care coordination encounter was 20.7 minutes. The most common care coordination activity was referral management (21%) and the care coordinator in the practice most often contacted parent/family and specialists (75%). Children with more severe asthma had more hospitalizations and emergency department (ED) visits than children with less severe asthma. There was a significant decrease in school absences, ED visits and acute care visits for children/youth with asthma with increasing length of time in a medical home program (p < 0.05). CONCLUSION: Care coordination for children/youth with asthma is feasible and may yield improvements in healthcare utilization, expenditures and quality of life. Larger-scale implementation of care coordination and medical home models for children/youth with asthma and other diagnoses are warranted.

Echocardiographic predictors of mitral regurgitation in high school and collegiate competitive athletes.

Previous studies have compared cardiac morphology between strength and endurance athletes, but few studies have examined predictors of valvular regurgitation in this population. This study evaluated predictors of mitral regurgitation (MR) in high school and collegiate athletes. Athletes in 9 different sports (n = 144) underwent transthoracic echocardiography. We used 97 sedentary patients as controls. Left ventricular (LV) end-diastolic diameter, septal wall thickness, posterior wall thickness, relative wall thickness (RWT), LV mass, LV volume, and mass/volume ratio were calculated and indexed for body surface area. Valvular regurgitation was graded from 0 to 4. Using logistic regression, RWT was associated with decreased odds of MR, with each 0.07 increase in RWT accounting for a 0.52 decrease in odds of MR (95% confidence interval 0.32 to 0.85, p = 0.009). Differences were best exemplified by comparison of soccer and football players, who represent predominantly aerobic versus predominantly isometric exercise, respectively. Soccer players had a larger LV end-diastolic index (29.2 ± 3 vs 24.9 ± 2.6, p <0.001), lesser RWT (0.33 ± 0.06 vs 0.38 ± 0.08, p = 0.014), and lower mass/volume ratio (1.04 ± 0.21 vs 1.29 ± 0.3, p <0.001), with a greater prevalence of MR (45.8% vs 8.5%). Sedentary subjects were similar to football players in LV volume and soccer players in LV mass. In conclusion, RWT is a negative predictor of MR, with higher values reducing the odds of MR. MR appears to be related to the relation between wall thickness and chamber size rather than chamber size alone.

Rinomanometría, función mucociliar y citología nasal en la evaluación de aire caliente / Rhinomanometry, mucociliar function and nasal citology in the evaluation of warm air

Se estudiaron 75 pacientes para evaluar el uso de aire caliente en pacientes con rinitis alérgica. El rango de edad de los pacientes fue de 10 a 69 años con un media de 32.8. Los resultados preliminares de este estudio demostraron que con la inhalación de aire caliente, hay un aumento de la resistencia nasal de 0.215 a los 3 y 5 minutos posteriores, sin variar a las 2 horas P < 0.05. La función mucociliar se midión por la prueba de sacarina, se encontró una correlación significativa entre los dos grupos de pacientes, con aire caliente y con aire normal gama = .972, pero sin ser significativo P > 0.01. La citología nasal no demostró anomalías morfológicas en el grupo estudiado