Multistep Parametric Processes in Nonlinear Optics

We present a comprehensive overview of different types of parametric interactions in nonlinear optics which are associated with simultaneous phase-matching of several optical processes in quadratic nonlinear media, the so-called multistep parametric interactions. We discuss a number of possibilities of double and multiple phase-matching in engineered structures with the sign-varying second-order nonlinear susceptibility, including (i) uniform and non-uniform quasi-phase-matched (QPM) periodic optical superlattices, (ii) phase-reversed and periodically chirped QPM structures, and (iii) uniform QPM structures in non-collinear geometry, including recently fabricated two-dimensional nonlinear quadratic photonic crystals. We also summarize the most important experimental results on the multi-frequency generation due to multistep parametric processes, and overview the physics and basic properties of multi-color optical parametric solitons generated by these parametric interactions.Comment: To be published in Progress in Optic

Why do you drink caffeine? The development of the Motives for Caffeine Consumption Questionnaire (MCCQ) and its relationship with gender, age and the types of caffeinated beverages

Caffeine is the most popular psychoactive substance that is consumed worldwide. As motives influence behavior, investigation of the motivational background of caffeine consumption should help provide a better understanding of the popularity of caffeinated products. The present study aimed (i) to explore and operationalize the motives of caffeine consumption and (ii) to reveal possible differences in the motives regarding gender, age and the type of caffeinated products consumed. Motives for caffeine consumption were collected from regular caffeine consumers (N = 26) and were informed by a review of the relevant literature. Following this, a cross-sectional study was conducted on a convenience sample of Hungarian university students and working adults (N = 598). The participants completed the Motives for Caffeine Consumption Questionnaire and the Caffeine Consumption Questionnaire. Six motivational factors were identified: Alertness, Habit, Mood, Social, Taste and Symptom Management. Women had higher scores on Habit, Social, Taste and Symptom Management. Younger participants had higher scores on Alertness than the older group, and the older group had higher scores on Habit and Symptom Management. Five types of caffeine users were identified. Those who consumed (i) coffee, (ii) tea, (iii) energy drinks, (iv) coffee and tea and (v) mixed drinks. Several differences between the five groups were revealed across all motives except for Taste. The present study developed a robust psychometric instrument for assessing caffeine consumption motives. The factors varied in importance in relation to gender, age and caffeine consumption habits

A multicenter retrospective study of patients with pulmonary hypertension transitioned from inhaled to oral treprostinil

Oral treprostinil has recently been shown to delay disease progression in patients with pulmonary arterial hypertension in a long-term outcomes study. The potential advantages of an oral formulation have resulted in patients transitioning from inhaled to oral treprostinil. The current study reports a retrospective analysis of patients who transitioned from treatment with inhaled to oral treprostinil. A multicenter retrospective chart review was conducted for 29 patients with pulmonary hypertension that transitioned from inhaled to oral treprostinil. Data were collected from inhaled treprostinil initiation and patients were followed until discontinuation of oral treprostinil or the end of the observation period. Persistence was calculated using Kaplan-Meier estimates. Prior to transition to oral treprostinil, patients had received inhaled treprostinil for a median of 643 (IQR: 322-991) days and 52% of patients were New York Heart Association/World Health Organization Functional Class III. For patients that cross-titrated between formulations, the median time to complete the cross titration was 24 (IQR: 1-57) days. At 16- and 24-weeks post-transition, oral treprostinil persistence was 86 and 76%, respectively. Persistence was 59% at 52 weeks post-transition. Clinical stability for the majority of patients at first follow-up post-transition was suggested based on available New York Heart Association/World Health Organization Functional Classification. Transitions from inhaled to oral treprostinil appeared safe and tolerable in the short-term. Additional prospective studies are needed to fully evaluate the safety and efficacy of transitions from inhaled to oral treprostinil

Contemporary risk scores predict clinical worsening in pulmonary arterial hypertension - An analysis of FREEDOM-EV

BACKGROUND: Risk scores integrate clinical variables emphasizing symptoms, exercise capacity, and measures of cardiac strain to predict clinical outcome better than any single value in pulmonary arterial hypertension (PAH). Risk scores have demonstrated prognostic utility for outcomes in registries, and recent studies have suggested that they are also therapy-responsive in controlled trials. METHODS: FREEDOM-EV, a global, placebo-controlled, event-driven study, randomized 690 PAH participants 1:1 to oral treprostinil (TRE) or placebo. Clinical assessments were performed every 12 weeks to calculate the non-invasive French risk assessment (FRA), 4-strata COMPERA, REVEAL 2.0, and REVEAL Lite 2; median follow-up was 58 weeks. The Week 12 risk scores were used to predict time to clinical worsening (from Week 12) with Kaplan-Meier product-limit estimates. Log-rank test was used to calculate the statistical difference among risk categories, and mediation analysis tested the hypothesis that improvements in risk score contributed to reduced likelihood for clinical worsening. We assessed the previously proposed net clinical benefit (achievement of FRA low-risk status and absence of clinical worsening). RESULTS: Both REVEAL scores, COMPERA, and FRA at Week 12 predicted subsequent clinical worsening better than baseline risk. Mediation analysis demonstrated that Week 12 risk score reduction explained part of TRE\u27s effect on clinical worsening, especially for those with higher baseline risk. TRE assigned participants were more likely to achieve the previously proposed net clinical benefit at Weeks 24 and beyond. Few participants who achieved \u27net clinical benefit\u27 had subsequent clinical worsening. CONCLUSIONS: Contemporary risk scores were therapy responsive in FREEDOM-EV and early improvements predicted subsequent outcomes. This post hoc analysis suggests that risk scores may be a surrogate for clinical worsening

Long-term study of oral treprostinil to treat pulmonary arterial hypertension. dosing, tolerability, and pharmacokinetics

Oral treprostinil may be an option for low- and intermediate-risk patients with pulmonary arterial hypertension, a rare lung vascular disease. This open-label extension study collected data on participants who completed previously reported, placebo- controlled oral treprostinil studies. Eligible participants had completed the prospective parent studies and took increasing doses of oral treprostinil twice daily; some later transitioned to three times daily dosing. Investigators measured 6-minute walk distance at Month 12 as the sole efficacy measure but collected adverse events throughout the study. A single center measured pharmaco- kinetics in 13 subjects who changed dosing from twice daily to three times daily. Eight hundred and ninety-four participants enrolled and 71% completed one year of therapy, with a median total daily dose of 7 mg and a median 6-minute walk distance increase of 22 m (interquartile range, 14 to 67 m). Subjects achieving higher doses had larger increases in 6-minute walk distance; 42% of participants completed three years of therapy. Adverse events were typical for prostacyclin class therapy, but prostacyclin- type adverse events may have been better tolerated with three times daily dosing in 105 participants. In 13 participants transitioned to three times daily dosing with pharmacokinetic measurements before and after, trough drug levels were higher with three times daily dosing. Oral treprostinil is associated with modest but durable, dose-responsive effects on exercise tolerance for those who remained on therapy at one year in this prospective, uncontrolled study. Three times daily dosing was associated with higher trough levels and better tolerability. The recently completed Freedom-EV study will provide further insights into the utility of oral treprostini

express long term study of oral treprostinil to treat pulmonary arterial hypertension dosing tolerability and pharmacokinetics

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Practical management of oral treprostinil in patients with pulmonary arterial hypertension: Lessons from ADAPT, EXPEDITE, and expert consensus

Background: Oral treprostinil is a prostacyclin analogue approved to treat pulmonary arterial hypertension (PAH) by delaying disease progression and improving exercise capacity. Higher doses of oral treprostinil correlate with increased treatment benefit. Titrations may be challenging due to common side effects of prostacyclin-class therapies. Study design and methods: The multicenter, prospective, real-world, observational ADAPT Registry study followed adult patients with PAH for up to 78 weeks after initiating oral treprostinil (NCT03045029). Dosing, titration, and transitions of oral treprostinil were at the discretion of the prescriber. Patient-reported incidence and treatment of common side effects were collected to understand side effect management and tolerability. Insights from literature and expert recommendations were added to provide a consolidated resource for oral treprostinil use. Results: In total, 139 participants in ADAPT completed ≥1 weekly survey; (median age 60.0 years, 76% female). Median treatment duration of oral treprostinil was 13.1 months. During early therapy (Months 1-5), 62% (78/126) of patients reported headache and diarrhea, and 40% (50/126) reported nausea. At Month 6, many patients who reported side effects during early therapy reported an improvement (61% headache, 44% diarrhea, 70% nausea). Common side effect treatments, including acetaminophen, loperamide, and ondansetron were effective. Approximately one-quarter of patients reporting the most common side effects were untreated at Month 6. Conclusion: Patient selection for, and initiation and titration of oral treprostinil should be individualized and may include parenteral treprostinil induction-transition for faster titration. Assertive side effect management may help reach higher and more efficacious doses of oral treprostinil

An expert panel Delphi consensus statement on the use of palliative care in the management of patients with pulmonary arterial hypertension

Mortality in pulmonary arterial hypertension (PAH) remains high and referral to palliative or supportive care (P/SC) specialist services is recommended when appropriate. However, access to P/SC is frequently a challenge for patients with a noncancer diagnosis and few patients living with PAH report P/SC involvement in their care. A modified Delphi process of three questionnaires completed by a multidisciplinary panel ( = 15) was used to develop expert consensus statements regarding the use of P/SC to support patients with PAH. Panelists rated their agreement with each statement on a Likert scale. There was a strong consensus that patients should be referred to P/SC when disease symptoms become unmanageable or for end-of-life care. Services that achieved consensus were pain management techniques, end-of-life care, and psychosocial recommendations. Palliative or supportive care should be discussed with patients, preferably in-person, when disease symptoms become unmanageable, when starting treatment, when treatment-related adverse events occur or become refractory to initial intervention. Care partners and patient support groups were considered important in improving a patient\u27s overall health outcomes, treatment adherence, and perception of care. Most patients with PAH experience cognitive and/or psychosocial changes and those who receive psychosocial management have better persistence and/or compliance with their treatment. These consensus statements provide guidance to healthcare providers on the who and when of referral to palliative care services, as well as the importance of focusing on the psychosocial aspects of patient care and quality of life