Pulse Energy and Pulse Duration Effects in the Ionization and Fragmentation of Iodomethane by Ultraintense Hard X Rays

The interaction of intense femtosecond x-ray pulses with molecules sensitively depends on the interplay between multiple photoabsorptions, Auger decay, charge rearrangement, and nuclear motion. Here, we report on a combined experimental and theoretical study of the ionization and fragmentation of iodomethane (CH_{3}I) by ultraintense (∼10^{19}  W/cm^{2}) x-ray pulses at 8.3 keV, demonstrating how these dynamics depend on the x-ray pulse energy and duration. We show that the timing of multiple ionization steps leading to a particular reaction product and, thus, the product's final kinetic energy, is determined by the pulse duration rather than the pulse energy or intensity. While the overall degree of ionization is mainly defined by the pulse energy, our measurement reveals that the yield of the fragments with the highest charge states is enhanced for short pulse durations, in contrast to earlier observations for atoms and small molecules in the soft x-ray domain. We attribute this effect to a decreased charge transfer efficiency at larger internuclear separations, which are reached during longer pulses.

POS0678 DOES SILDENAFIL IMPROVE ENDOTHELIAL DYSFUNCTION IN RHEUMATOID ARTHRITIS? – A PILOT CLINICAL TRIAL

Background:

Rheumatoid arthritis (RA) is independently associated with an increased risk of cardiovascular disease (CVD). One of the early stages of atherosclerosis is endothelial dysfunction, which is increased in RA. Using drugs to target endothelial dysfunction is a promising novel strategy for CVD prevention in RA. Sildenafil has been shown to improve endothelial function in diabetics, who have similar increased CVD risk. Our hypothesis was that sildenafil use may be a novel primary CVD prevention strategy in RA.

Objectives:

To determine if sildenafil use in RA patients improves endothelial dysfunction (as measured by brachial artery flow-mediated dilation [FMD] and peripheral arterial tone [PAT]), as well as serum inflammatory and atherosclerosis biomarkers.

Methods:

This NIH-funded study was a phase II, randomized double-blind placebo-controlled crossover efficacy trial of 25 RA patients, with no known history of CVD, but at least one traditional CVD risk factor. Patients were randomized 1:1 to receive either sildenafil or placebo for 3 months, then after a 2-week washout, crossed over to each respective group for an additional 3 months. Vascular studies (FMD and PAT) and serum atherosclerosis biomarkers (e-Selectin, ICAM-1, VCAM-1) were performed at baseline, 3 months pre- and post-washout, and 6 months. Adverse events were collected. Given the cross-over design, analyses included a random effects model for within-subject comparisons of sildenafil versus placebo periods, adjusting for the baseline (FMD or EndoPAT) within that period and a term for treatment order. All tests were 2-sided with α=0.05.

Results:

A total of 233 subjects were assessed for eligibility, with 25 subjects being randomized after written informed consent. A total of 13 subjects were randomized to placebo first, and 12 to sildenafil first. Baseline characteristics were similar between those randomized to Placebo vs. Sildenafil first. Mean age was 62.0+/-10.9 years; 84% were female; and 92% were white. A total of 6 adverse events experienced in 3 subjects occurred. The primary endpoint (increase in %FMD in Sildenafil period vs. Placebo period) was not significant (p=0.19). However, note the study was powered at 80% to detect an effect size of 0.37 for change in %FMD or biomarker with a sample size of 60, not 25. However, sildenafil use was associated with a significant increase (improvement) by 0.200 units of PAT ratio (p=0.003) compared with placebo, adjusted by treatment order and baseline PAT ratio (within the given treatment period). Exploratory linear mixed models comparing e-Selectin, ICAM-1, and VCAM-1 between Sildenafil vs. Placebo periods, adjusted for treatment order and the baseline biomarker level, did not show any significant differences except for ICAM-1 (55.3 units higher in Sildenafil vs. Placebo periods, p=0.011).

Conclusion:

In this pilot trial of 25 RA subjects, sildenafil use was associated with a significant increase (improvement) in endothelial function as measured by PAT. However, there was no significant difference in FMD. The study is limited due to the small sample size, which was impacted by slow recruitment as well as the COVID-19 pandemic. Future larger studies are required to assess whether other PDE5 inhibitors may improve endothelial dysfunction in RA and other autoimmune disease patients at high risk of CVD.

References:

[1]Maradit-Kremers H, Crowson CS, Nicola PJ, et al. Increased unrecognized coronary heart disease and sudden deaths in rheumatoid arthritis: a population-based cohort study. Arthritis Rheum 2005;52:402-11.

[2]Peters MJ, van Halm VP, Voskuyl AE, et al. Does rheumatoid arthritis equal diabetes mellitus as an independent risk factor for cardiovascular disease? A prospective study. Arthritis Rheum 2009;61:1571-9.

[3]Deyoung L, Chung E, Kovac JR, et al. Daily use of sildenafil improves endothelial function in men with type 2 diabetes. J Andrology 2012;33:176-80.

Disclosure of Interests:

None declared

The O K-2V spectrum of CO: the influence of the second core-hole

Using synchrotron radiation in the tender X-ray regime, a photoelectron spectrum showing the formation of single site double-core-hole pre-edge states, involving the K shell of the O atom in CO, has been recorded by means of high-resolution electron spectroscopy. The experimentally observed structures have been simulated, interpreted and assigned, employing state-of-the-art ab initio quantum chemical calculations, on the basis of a theoretical model, accounting for their so-called direct or conjugate character. Features appearing above the double ionization threshold have been reproduced by taking into account the strong mixing between multi-excited and continuum states. The shift of the σ* resonance below the double ionization threshold, in combination with the non-negligible contributions of multi-excited configurations in the final states reached, gives rise to a series of avoided crossings between the different potential energy curves.

Small freshwater ecosystems with dissimilar microbial communities exhibit similar temporal patterns

Despite small freshwater ecosystems being biodiversity reservoirs and contributing significantly to greenhouse fluxes, their microbial communities remain largely understudied. Yet, microorganisms intervene in biogeochemical cycling and impact water quality. Because of their small size, these ecosystems are in principle more sensitive to disturbances, seasonal variation and pluri-annual climate change. However, how microbial community composition varies over space and time, and whether archaeal, bacterial and microbial eukaryote communities behave similarly remain unanswered. Here, we aim to unravel the composition and intra/interannual temporal dynamic patterns for archaea, bacteria and microbial eukaryotes in a set of small freshwater ecosystems. We monitored archaeal and bacterial community composition during 24 consecutive months in four ponds and one brook from northwestern France by 16S rRNA gene amplicon sequencing (microbial eukaryotes were previously investigated for the same systems). Unexpectedly for oxic environments, bacterial Candidate Phyla Radiation (CPR) were highly diverse and locally abundant. Our results suggest that microbial community structure is mainly driven by environmental conditions acting over space (ecosystems) and time (seasons). A low proportion of operational taxonomic units (OTUs) (<1%) was shared by the five ecosystems despite their geographical proximity (2-9 km away), making microbial communities almost unique in each ecosystem and highlighting the strong selective influence of local environmental conditions. Marked and similar seasonality patterns were observed for archaea, bacteria and microbial eukaryotes in all ecosystems despite strong turnovers of rare OTUs. Over the 2-year survey, microbial community composition varied despite relatively stable environmental parameters. This suggests that biotic associations play an important role in interannual community assembly.

Impact of an Education Programme on IBD Patients' Skills: Results of a Randomised Controlled Multicentre Study [ECIPE]

BACKGROUND

Better patient knowledge on inflammatory bowel disease [IBD] could improve outcome and quality of life. The aim of this study was to assess if an education programme improves IBD patients' skills as regards their disease.

METHODS

The GETAID group conducted a prospective multicentre randomised controlled study. IBD patients were included at diagnosis, or after a significant event in the disease course. Patients were randomised between 'educated' or control groups for 6 months. Education was performed by trained health care professionals. A psycho-pedagogic score [ECIPE] was evaluated by a 'blinded' physician at baseline and after 6 and 12 months [M6 and M12]. The primary endpoint was the increase of ECIPE score at M6 of more than 20%.

RESULTS

A total of 263 patients were included in 19 centres (male:40%; median age:30.8; Crohn's disease [CD]:73%). Of these, 133 patients were randomised into the educated group and 130 into the control group. The median relative increase in ECIPE score at M6 was higher in the educated group as compared with the control group (16.7% [0-42.1%] vs 7% [0-18.8%], respectively, p = 0.0008). The primary endpoint was met in 46% vs 24% of the patients in the educated and control groups, respectively [p = 0.0003]. A total of 92 patients met the primary endpoint. In multivariate analysis, predictors of an increase of at least 20% of the ECIPE score were randomisation in the educated group (odds ratio [OR] = 2.59) and no previous surgery [OR = 1.92].

CONCLUSIONS

These findings support the set-up of education programmes in centres involved in the management of IBD patients.

Bedside ultrasound assessments of jugular venous compliance to track central venous pressure change during the treatment of decompensated heart failure

Background

Accurate volume status assessment is crucial for the treatment of acute decompensated heart failure (ADHF). Volume status assessment by physical exam is inaccurate, necessitating invasive measurement with right heart catheterization (RHC), which carries safety, pragmatic (scheduling, holding anticoagulants, etc) and financial burdens. Therefore, a reliable, non-invasive, cost-effective alternative is desired. Previously, we developed an ultrasound (US) based technique to measure internal jugular vein (IJV) compliance during RHC which was used for single time point central venous pressure (CVP) predictions. We now aim to apply this technique to track acute changes in CVP during diuresis for ADHF in patients with an in-dwelling pulmonary artery catheter.

Purpose

The objective of our study was to devise a rapid, portable and reliable alternative to RHC to track acute volume changes during treatment of ADHF.

Methods

We used an observational, prospective study design and recruited 15 patients from the CCU between 7/19–12/19 being treated for ADHF (systolic or diastolic) with IV diuretics +/−inotropic agents who underwent PA catheter insertion for continuous CVP monitoring. 13 of 15 patients received milrinone infusions. US images of the IJV were obtained at end expiration and during the strain phase of Valsalva at multiple 2–3 hr intervals. Change in IJV cross sectional area (ImageJ) was used as a measure of IJV compliance. Patients unable to perform the Valsalva maneuver and on mechanical circulatory support were excluded.

Results

Calculated % change in CSA of IJV was plotted against CVP. An inverse relationship was observed between CVP and % change in CSA of IJV. The data was fit with an inverse exponential regression shown in Figure 1 (R2=0.36, root mean square error = 3.19). Fivefold cross validation showed a stable model for predicting CVP based CSA (R2=0.34, root mean square error = 3.26)

Conclusion

Serial portable US assessment of IJV compliance can act a surrogate measure of CVP and,therefore, can provide reliable information on acute hemodynamic changes in ADHF.

Funding Acknowledgement

Type of funding source: None

[Puffy hand syndrome: A little-known diagnosis]

INTRODUCTION

Puffy hand syndrome is a rare complication of intravenous drug addiction. Diagnosis is based on the patient's history and clinical examination.

OBSERVATIONS

A woman and two men, aged 42, 39 and 36 years old, are described. All had a history of intravenous drug use of heroin and oral buprenorphine misuse. Puffy hand syndrome appeared during drug addiction (n = 2) or after its withdrawal (n = 1). It was associated with acrocyanosis (n = 1) or injection scars (n = 1). Upper limb ultrasonography showed sequelae of venous (n = 3) or arterial (n = 1) thrombosis. An upper limb lymphoscintigraphy in one patient showed decreased radionuclide uptake of axillary lymph node and subdermal reflux tracer in the forearm. Treatment was based on low-stretch bandages to reduce the volume and then elastic compression sleeve for long-term stabilization.

CONCLUSION

Puffy hand syndrome seen in intravenous drug addicts is poorly understood. It is a chronic complication despite the cessation of drug use. This syndrome has to become more widely known because its management is mandatory, although symptomatic.

Resonant Inelastic X-Ray Scattering Reveals Hidden Local Transitions of the Aqueous OH Radical

Resonant inelastic x-ray scattering (RIXS) provides remarkable opportunities to interrogate ultrafast dynamics in liquids. Here we use RIXS to study the fundamentally and practically important hydroxyl radical in liquid water, OH(aq). Impulsive ionization of pure liquid water produced a short-lived population of OH(aq), which was probed using femtosecond x-rays from an x-ray free-electron laser. We find that RIXS reveals localized electronic transitions that are masked in the ultraviolet absorption spectrum by strong charge-transfer transitions-thus providing a means to investigate the evolving electronic structure and reactivity of the hydroxyl radical in aqueous and heterogeneous environments. First-principles calculations provide interpretation of the main spectral features.

SAT0652-HPR CHRONIC DISEASE MANAGEMENT AND HEALTH TECHNOLOGY READINESS OF PATIENTS WITH SYSTEMIC SCLEROSIS IN SWITZERLAND – A CROSS-SECTIONAL STUDY

Background:

People living with systemic sclerosis (SSc) often lack access to coordinated, specialized care and self-management support from qualified healthcare professionals. Such gaps lead to significant unmet health needs and inability to get preventive services. The Chronic Care Model (CCM) has been used to guide disease management across a wide range of chronic conditions. The CCM often uses e-health technologies to address self-management problems, connect patients with clinicians and reduce patient travel requirements.

Objectives:

To evaluate current SSc care practice patterns and elicit patient health technology readiness to define relevant aspects and resources needed to improve SSc chronic disease management.

Methods:

We employed a cross-sectional survey using the 20-item Patient Assessment of Chronic Illness Care (PACIC) instrument to assess how aspects of SSc care align with key components of the CCM.1Six items drawn from the ‘5A’ (ask, advise, agree, assist, and arrange) model of behavioural counselling were included (all 26 items scored on 5-point scale, 1=never to 5=always). Acceptance of health technology was evaluated by adapting and combining questionnaires from Vanhoof2and Halwas3. German and French speaking SSc patients (>18 years) were recruited from university/cantonal hospitals and the Swiss scleroderma patients’ association. Participants completed anonymous paper/online questionnaires. Data were analysed descriptively.

Results:

Of 101 SSc patients, most were female (76%), spoke German (78%) and had a median age of 60 years (IQR: 50-68). Median disease duration was 8 years (IQR: 5-15), spanning a range of severity (31% limited SSc, 36% diffuse SSc, 3% overlap syndrome). One-quarter (25%) did not know their disease subset.

The mean overall PACIC score was relatively low (2.91±0.95) indicating that care was ‘never’ to ‘generally not’ aligned with the CCM. Lowest mean subscale scores related to Follow-up/ Coordination (2.64±1.02), Goal setting (2.68±1.07) and Problem-solving/Contextual Counselling (2.94±1.22). The single items ‘Given a copy of my treatment plan’ (1.99±1.38) and ‘Encouraged to attend programs in the community’ (1.89±1.16) were given the lowest ratings. The ‘5A’ summary score was 2.84±0.97.

In terms of technology readiness, 43% completed the survey online. Most participants owned a smartphone (81%), laptop (63%) and/or desktop computer (46%). The overwhelming majority of patients (91%) reported using the Internet in the last year – primarily for communication (e.g. emails, text messages). Participants indicated relatively little experience with e-health applications and participating in SSc online forums or self-help groups.

Conclusion:

To improve chronic disease management of SSc patients in Switzerland, current care practices warrant reengineering taking CCM components into account. Specific unmet needs relate to self-management support, help patients set individualized goals, and coordinate continuous care. Web-based technologies incorporating user-centred design principles may be a reasonable option for improving care.

References:

[1]Glasgow, RE, et al. Development and validation of the Patient Assessment of Chronic Illness Care (PACIC).Med Care2005; 43(5): 436-44

[2]Vanhoof, JM, et al. Technology Experience of Solid Organ Transplant Patients and Their Overall Willingness to Use Interactive Health Technology. J Nurs Scholarsh2018; 50(2): 151-62

[3]Halwas, N, et al. eHealth literacy, Internet and eHealth service usage: a survey among cancer patients and their relatives. J Cancer Res Clin Oncol2017; 143(11): 2291-99

Disclosure of Interests:

Agnes Kocher Grant/research support from: Sandoz to support the development of an eLearning module for patients with rheumatic diseases., Michael Simon: None declared, Carlo Chizzolini Consultant of: Boehringer Ingelheim, Roche, Oliver Distler Grant/research support from: Grants/Research support from Actelion, Bayer, Boehringer Ingelheim, Competitive Drug Development International Ltd. and Mitsubishi Tanabe; he also holds the issued Patent on mir-29 for the treatment of systemic sclerosis (US8247389, EP2331143)., Consultant of: Consultancy fees from Actelion, Acceleron Pharma, AnaMar, Bayer, Baecon Discovery, Blade Therapeutics, Boehringer, CSL Behring, Catenion, ChemomAb, Curzion Pharmaceuticals, Ergonex, Galapagos NV, GSK, Glenmark Pharmaceuticals, Inventiva, Italfarmaco, iQvia, medac, Medscape, Mitsubishi Tanabe Pharma, MSD, Roche, Sanofi and UCB, Speakers bureau: Speaker fees from Actelion, Bayer, Boehringer Ingelheim, Medscape, Pfizer and Roche, Andrew A. Dwyer: None declared, Peter Villiger Consultant of: MSD, Abbvie, Roche, Pfizer, Sanofi, Speakers bureau: Roche, MSD, Pfizer, Ulrich Walker Grant/research support from: Ulrich Walker has received an unrestricted research grant from Abbvie, Consultant of: Ulrich Walker has act as a consultant for Abbvie, Actelion, Boehringer Ingelheim, Bristol-Myers Squibb, Celgene, MSD, Novartis, Pfizer, Phadia, Roche, Sandoz, Sanofi, and ThermoFisher, Paid instructor for: Abbvie, Novartis, and Roche, Speakers bureau: Abbvie, Actelion, Bristol-Myers Squibb, Celgene, MSD, Novartis, Pfizer, Phadia, Roche, Sandoz, and ThermoFisher, Dunja Nicca: None declared

THU0623-HPR REVISION AND VALIDATION OF THE GERMAN VERSION OF THE SYSTEMIC SCLEROSIS QUALITY OF LIFE QUESTIONNAIRE (SSCQOL) WITH MOKKEN SCALE ANALYSIS

Background:

The Systemic Sclerosis Quality of Life Questionnaire (SScQoL) has been validated in six European languages.1Previous adaptation into German revealed issues with the dichotomous response structure in 10 items necessitating a review of the tool and further psychometric testing with patients in German speaking countries.

Objectives:

The aim of this study was to assess the German version of the SScQoL, extend the response structure and test its construct validity using Mokken scale analysis.

Methods:

This was a mixed methods study involving cognitive debriefing and survey methods. The expert committee extended the response structure of the 10 items from dichotomous to polytomous (4-point) responses: ‘always’, ‘usually’, ‘sometimes’ and ‘never’. In cognitive debriefing, a small convenience sample of patients with SSc completed the new version while ‘thinking aloud’ and commented on relevance of the items and the response structure.

Results:

In cognitive debriefing, six patients with SSc completed the new German SScQoL and reported problems with the remaining dichotomous items. These were subsequently converted into polytomous 4-point response structure by the expert committee.

Conclusion:

The German SScQoL has been revised into polytomous item structure and shown to be a valid and reliable measure of health-related quality of life in SSc. Further cross-cultural validity tests are required to assess its measurement equivalence with other SScQoL versions and thus enable multinational comparisons.

References:

[1]Ndosi M, Alcacer-Pitarch B, Allanore Y et al. Common measure of quality of life for people with systemic sclerosis across seven European countries: a cross-sectional study. Ann Rheum Dis, 2018; 77: 1032-1038

Table 1.

Mokken scale analysis of the revised German SScQoL

Subscale (items)Scalability (H)Standard errorFunction (6)0.6640.048Emotional (13)0.6520.060Sleep (2)0.7980.061Social (6)0.6920.053Pain (2)0.9600.029Global scale (29)0.6230.062

Table legend: scalabilityH≥ 0.50 = strong, 0.49 to 0.40 = moderate, 0.39 to 0.30 = weak, while values of < 0.30 are not considered as unidimensional.

Disclosure of Interests:

Agnes Kocher Grant/research support from: Sandoz to support the development of an eLearning module for patients with rheumatic diseases., Mwidimi Ndosi Grant/research support from: Bristol Myers Squibb, Consultant of: Janssen, Pfizer, Kirsten Hoeper Consultant of: AbbVie, Celgene,, Speakers bureau: Abbvie, Chugai, Novartis, Lilly, Celgene, Sandoz Hexal, Michael Simon: None declared, Dunja Nicca: None declared

Fluorescence Time Delay in Multistep Auger Decay as an Internal Clock

Differences in postcollision interaction (PCI) effects on Kr L_{3}M_{4,5}M_{4,5} Auger electron spectra were observed, depending on whether the initial photoionization occurred slightly above the K threshold or slightly above the L_{3} threshold. For the former, KL fluorescence emission most likely happens and then Auger processes due to the L_{3} hole follow. The time delay due to fluorescence causes a reduced shift of the Auger peak and tailing toward lower energy, since the Auger overtaking of the photoelectron happens later in time and at a location farther away from the ionic core, compared to the case for the simple one-step L_{3}M_{4,5}M_{4,5} Auger decay after L-shell photoionization. Time-dependent theory for PCI in multistep processes agrees well with experiment, illustrating the effect as an internal clock for the time-sequence of the dynamical process.

Size-dependent influence of NOx on the growth rates of organic aerosol particles

Atmospheric new-particle formation (NPF) affects climate by contributing to a large fraction of the cloud condensation nuclei (CCN). Highly oxygenated organic molecules (HOMs) drive the early particle growth and therefore substantially influence the survival of newly formed particles to CCN. Nitrogen oxide (NOx) is known to suppress the NPF driven by HOMs, but the underlying mechanism remains largely unclear. Here, we examine the response of particle growth to the changes of HOM formation caused by NOx. We show that NOx suppresses particle growth in general, but the suppression is rather nonuniform and size dependent, which can be quantitatively explained by the shifted HOM volatility after adding NOx. By illustrating how NOx affects the early growth of new particles, a critical step of CCN formation, our results help provide a refined assessment of the potential climatic effects caused by the diverse changes of NOx level in forest regions around the globe.