Discovery of molybdenum based nitrogen fixation catalysts with genetic algorithms.

Computational discovery of organometallic catalysts that effectively catalyze nitrogen fixation is a difficult task. The complexity of the chemical reactions involved and the lack of understanding of natures enzyme catalysts raises the need for intricate computational models. In this study, we use a dataset of 91 experimentally verified ligands as starting population for a Genetic Algorithm (GA) and use this to discover molybdenum based nitrogen fixation catalyst in trigonal bipyramidal and octahedral configurations. Through evolutionary discovery with a semi-empirical quantum method driven GA and a density functional theory (DFT) based screening process, we find 3 promising catalyst candidates that are shown to effectively catalyze the first protonation step of the Schrock cycle. Synthetic accessibility (SA) scores are used to guide the GA towards reasonable ligands and the work features a description of the GA framework, including pre-screening of catalyst candidates that involves assignment of metal coordination atoms and catalyst stereoisomers. This research thus not only offers insights into the specific field of molybdenum-based catalysts for nitrogen fixation but also demonstrates the broader applicability and potential of genetic algorithms in the field of catalyst discovery and materials science.

Addressing bioreactor hiPSC aggregate stability, maintenance and scaleup challenges using a design of experiment approach.

BACKGROUND: Stem cell-derived therapies hold the potential for treatment of regenerative clinical indications. Static culture has a limited ability to scale up thus restricting its use. Suspension culturing can be used to produce target cells in large quantities, but also presents challenges related to stress and aggregation stability. METHODS: Utilizing a design of experiments (DoE) approach in vertical wheel bioreactors, we evaluated media additives that have versatile properties. The additives evaluated are Heparin sodium salt (HS), polyethylene glycol (PEG), poly (vinyl alcohol) (PVA), Pluronic F68 and dextran sulfate (DS). Multiple response variables were chosen to assess cell growth, pluripotency maintenance and aggregate stability in response to the additive inputs, and mathematical models were generated and tuned for maximal predictive power. RESULTS: Expansion of iPSCs using 100 ml vertical wheel bioreactor assay for 4 days on 19 different media combinations resulted in models that can optimize pluripotency, stability, and expansion. The expansion optimization resulted in the combination of PA, PVA and PEG with E8. This mixture resulted in an expansion doubling time that was 40% shorter than that of E8 alone. Pluripotency optimizer highlighted the importance of adding 1% PEG to the E8 medium. Aggregate stability optimization that minimizes aggregate fusion in 3D culture indicated that the interaction of both Heparin and PEG can limit aggregation as well as increase the maintenance capacity and expansion of hiPSCs, suggesting that controlling fusion is a critical parameter for expansion and maintenance. Validation of optimized solution on two cell lines in bioreactors with decreased speed of 40 RPM, showed consistency and prolonged control over aggregates that have high frequency of pluripotency markers of OCT4 and SOX2 (> 90%). A doubling time of around 1-1.4 days was maintained after passaging as clumps in the optimized medium. Controlling aggregate fusion allowed for a decrease in bioreactor speed and therefore shear stress exerted on the cells in a large-scale expansion. CONCLUSION: This study resulted in a control of aggregate size within suspension cultures, while informing about concomitant state control of the iPSC state. Wider application of this approach can address media optimization complexity and bioreactor scale-up challenges.

Uncertain of uncertainties? A comparison of uncertainty quantification metrics for chemical data sets.

With the increasingly more important role of machine learning (ML) models in chemical research, the need for putting a level of confidence to the model predictions naturally arises. Several methods for obtaining uncertainty estimates have been proposed in recent years but consensus on the evaluation of these have yet to be established and different studies on uncertainties generally uses different metrics to evaluate them. We compare three of the most popular validation metrics (Spearman's rank correlation coefficient, the negative log likelihood (NLL) and the miscalibration area) to the error-based calibration introduced by Levi et al. (Sensors 2022, 22, 5540). Importantly, metrics such as the negative log likelihood (NLL) and Spearman's rank correlation coefficient bear little information in themselves. We therefore introduce reference values obtained through errors simulated directly from the uncertainty distribution. The different metrics target different properties and we show how to interpret them, but we generally find the best overall validation to be done based on the error-based calibration plot introduced by Levi et al. Finally, we illustrate the sensitivity of ranking-based methods (e.g. Spearman's rank correlation coefficient) towards test set design by using the same toy model ferent test sets and obtaining vastly different metrics (0.05 vs. 0.65).

Toward De Novo Catalyst Discovery: Fast Identification of New Catalyst Candidates for Alcohol-Mediated Morita-Baylis-Hillman Reactions.

Recently we have demonstrated how a genetic algorithm (GA) starting from random tertiary amines can be used to discover a new and efficient catalyst for the alcohol-mediated Morita-Baylis-Hillman (MBH) reaction. In particular, the discovered catalyst was shown experimentally to be eight times more active than DABCO, commonly used to catalyze the MBH reaction. This represents a breakthrough in using generative models for catalyst optimization. However, the GA procedure, and hence discovery, relied on two important pieces of information; 1) the knowledge that tertiary amines catalyze the reaction and 2) the mechanism and reaction profile for the catalyzed reaction, in particular the transition state structure of the rate-determining step. Thus, truly de novo catalyst discovery must include these steps. Here we present such a method for discovering catalyst candidates for a specific reaction while simultaneously proposing a mechanism for the catalyzed reaction. We show that tertiary amines and phosphines are potential catalysts for the MBH reaction by screening 11 molecular templates representing common functional groups. The method relies on an automated reaction discovery workflow using meta-dynamics calculations. Combining this method for catalyst candidate discovery with our GA-based catalyst optimization method results in an algorithm for truly de novo catalyst discovery.

Evaluating the Impact of a Novel Mobile Care Team on the Prevalence of Ambulatory Care Sensitive Conditions Presenting to Emergency Medical Services in Nova Scotia.

INTRODUCTION: Hospitalization due to ambulatory care sensitive conditions (ACSC) is a proxy measure for access to primary care. Emergency Medical Services (EMS) are increasingly called when primary care cannot be accessed. A novel paramedic-nurse EMS Mobile Care Team (MCT) was implemented in an under-serviced community. The MCT responds in a non-transport unit to referrals from EMS, emergency and primary care, and to low-acuity 911 calls in a defined geographic region. Our objective was to compare the prevalence of ACSC in ground ambulance (GA) responses before and after the introduction of the MCT. METHODS: A cross-sectional analysis of GA and MCT patients with ACSC (determined by chief complaint, clinical impression, treatment protocol, and medical history) from one year pre-MCT implementation to one year post-MCT implementation was conducted for the period of October 1, 2012, to September 30, 2014. Demographics were described. ACSC prevalence was compared using the chi-squared test. RESULTS: There were 975 calls pre-MCT and 1208 GA/95 MCT calls post-MCT. ACSC in GA patients pre- and post-MCT was similar: n=122, 12.5% vs. n=185, 15.3%; p=0.06. ACSC in patients seen by EMS (GA plus MCT) increased in the post-MCT period: 122 (12.5%) vs. 204 (15.7%) p=0.04. Pre-MCT implementation vs post-implementation, GA ACSC calls differed significantly by sex with higher female utilization (n=50 vs. n=105; p=0.007), but not age (65.38, ± 15.12 vs. 62.51 ± 20.48; p=0.16). Post-MCT, the prevalence of specific ACSC increased for GA: hypertension (p<0.001) and congestive heart failure (p=0.04). MCT patients with ACSC were less likely to have a primary care provider compared to GA (90.2% and 87.6% vs. 63.2%; p=0.003, p=0.004). CONCLUSION: The prevalence of ACSC did not decrease for GA with the introduction of the MCT, but ACSC in the overall patient population served by EMS increased. It is possible more patients with ACSC call, or are referred to EMS, for the new MCT service. Given that MCT patients were less likely to have a primary care provider, this may represent an increase in access to care or a shift away from other emergency/episodic care. These associations must be further studied to inform the ideal utility of adding such services to EMS and healthcare systems.

Computational Evolution Of New Catalysts For The Morita-Baylis-Hillman Reaction.

We present a de novo discovery of an efficient catalyst of the Morita-Baylis-Hillman (MBH) reaction by searching chemical space for molecules that lower the estimated barrier of the rate-determining step using a genetic algorithm (GA) starting from randomly selected tertiary amines. We identify 435 candidates, virtually all of which contain an azetidine N as the catalytically active site, which is discovered by the GA. Two molecules are selected for further study based on their predicted synthetic accessibility and have predicted rate-determining barriers that are lower than that of a known catalyst. Azetidines have not been used as catalysts for the MBH reaction. One suggested azetidine is successfully synthesized and showed an eightfold increase in activity over a commonly used catalyst. We believe this is the first experimentally verified de novo discovery of an efficient catalyst using a generative model.

Acute Microcirculatory Effects of Remote Ischemic Conditioning in Superficial Partial Thickness Burn Wounds.

Microcirculation is a critical factor in burn wound healing. Remote ischemic conditioning (RIC) has been shown to improve microcirculation in healthy skin and demonstrated ischemic protective effects on heart, kidney, and liver cells. Therefore, we examined microcirculatory effects of RIC in partial thickness burn wounds. The hypothesis of this study is that RIC improves cutaneous microcirculation in partial thickness burn wounds. Twenty patients with partial thickness burn wounds within 48 hours after trauma were included in this study. RIC was performed with an upper arm blood pressure cuff on a healthy upper arm using three ischemia cycles (5 min inflation to 200 mm Hg) followed by 10-minute reperfusion phases. The third and final reperfusion phase lasted 20 minutes. Microcirculation of the remote (lower/upper extremities or torso) burn wound was continuously quantified, using a combined Laser Doppler and white light spectrometry. The capillary blood flow in the burn wounds increased by a maximum of 9.6% after RIC (percentage change from baseline; P < .01). Relative hemoglobin was increased by a maximum of 2.8% (vs. baseline; P < .01), while cutaneous tissue oxygen saturation remained constant (P > .05). RIC improves microcirculation in partial thickness burn wounds by improving blood flow and elevating relative hemoglobin.

What the Heck?-Automated Regioselectivity Calculations of Palladium-Catalyzed Heck Reactions Using Quantum Chemistry.

We present a quantum chemistry (QM)-based method that computes the relative energies of intermediates in the Heck reaction that relate to the regioselective reaction outcome: branched (α), linear (ß), or a mix of the two. The calculations are done for two different reaction pathways (neutral and cationic) and are based on r 2SCAN-3c single-point calculations on GFN2-xTB geometries that, in turn, derive from a GFNFF-xTB conformational search. The method is completely automated and is sufficiently efficient to allow for the calculation of thousands of reaction outcomes. The method can mostly reproduce systematic experimental studies where the ratios of regioisomers are carefully determined. For a larger dataset extracted from Reaxys, the results are somewhat worse with accuracies of 63% for ß-selectivity using the neutral pathway and 29% for α-selectivity using the cationic pathway. Our analysis of the dataset suggests that only the major or desired regioisomer is reported in the literature in many cases, which makes accurate comparisons difficult. The code is freely available on GitHub under the MIT open-source license: https://github.com/jensengroup/HeckQM.

Paramedic Clinical Consults with a Paramedic or Nurse in an EMS Communications Center Compared to Traditional Online Physician Consults.

OBJECTIVES: In many emergency medical services (EMS) systems, a direct medical oversight physician is available to paramedics for mandatory and/or elective consultations. At the time of this study, a clinical support desk (CSD) was being implemented within the medical communications center of a provincial EMS system in addition to the physician resource. The CSD was initially staffed with a registered nurse or an advanced care paramedic. The objective of the current study was to compare CSD "peer to peer" consults versus physician consults with regards to consultation patterns, transport dispositions, and patient safety measures. METHODS: This retrospective cohort study analyzed 2 months before (September 1 to October 31, 2012) and 2 months after (September 1 to October 31, 2013) implementation of the CSD. In the before period, all clinical consults were fielded by the direct medical oversight physician. In the after period, consults were fielded by the physician, CSD or both. EMS databases were queried, and manual chart review and abstraction of audio recordings were done. Relapses back to EMS within 48 hours of non-transport were measured. RESULTS: 1621 consults were included, with 764 consults in the before period and 857 after (p = 0.02). The number of physician consults decreased from 764 before to 464 after (39.2%, p < 0.001), with the CSD taking 325 (37.9%) consults. The CSD was consulted more for police custody and trip destination. The physician was consulted more for cease resuscitation and clinical consults prior to medication administration. Overall non-transport rates were 595/764 before (77.9%), and 646/857 after (75.4%) (p = 0.2). Non-transports were 233/325 (71.7%) via the CSD, 364/464 (78.4%) via the physician, and 49/68 (72.1%) when both were involved (p = 0.07). Rate of relapse to EMS was similar before (25/524, 4.8%) and after (26/568, 4.6%) (p = 0.76), and between CSD (12/216, 5.5%) and physician consults (13/325, 4.0%) in the after period (p = 0.41). CONCLUSION: The introduction of a novel "peer-to-peer" consult program was associated with an increased total number of consults made and reduced call volume for direct medical oversight physicians. There was no change in the patient safety measure studied.

Combining mass spectrometry and machine learning to discover bioactive peptides.

Peptides play important roles in regulating biological processes and form the basis of a multiplicity of therapeutic drugs. To date, only about 300 peptides in human have confirmed bioactivity, although tens of thousands have been reported in the literature. The majority of these are inactive degradation products of endogenous proteins and peptides, presenting a needle-in-a-haystack problem of identifying the most promising candidate peptides from large-scale peptidomics experiments to test for bioactivity. To address this challenge, we conducted a comprehensive analysis of the mammalian peptidome across seven tissues in four different mouse strains and used the data to train a machine learning model that predicts hundreds of peptide candidates based on patterns in the mass spectrometry data. We provide in silico validation examples and experimental confirmation of bioactivity for two peptides, demonstrating the utility of this resource for discovering lead peptides for further characterization and therapeutic development.

Paramedic Endotracheal Intubation Success Rates Before and After an Intensive Airway Management Education Session.

Introduction Advanced airway management by paramedics is potentially life-saving, but carries a significant risk to patient safety and can be associated with poor clinical outcome if performed incorrectly. Previously, our team had found that an intensive education intervention demonstrated an improvement in paramedic performance on a written exam and increased confidence in airway skills. This study measured intubation success and the number of attempts per patient before and after intensive paramedic airway management education intervention. Methods A 10-hour mandatory course was taken by all advanced life support (ALS) paramedics in a provincial system (2009/04-07, n=~395). The course was done during semi-annual continuing education Emergency Health Services (EHS) in-services. These day-long courses were held in person over four months. The electronic charting database was queried for intubation attempts and successful placements 12 months before the training, during the four months of training, and 12 months post-training. The primary outcome is the difference in success rates between the before (pre-intervention) and after (post-intervention) periods. The secondary outcome is the number of attempts per patient. Stationarity of success in pre- and post-periods was tested. The model was fit tested using Maximum Likelihood regression, and variables were tested using the Wald test. Results A sample size of 476 intubation attempts in each of the pre- and post-periods was required to detect a 10% improvement with the pre-intervention success of 60%. A total of 1421 intubation attempts occurred; 674 pre-intervention, 604 post-intervention, and 143 during teaching. Seven attempts were excluded (success unknown). Intubation success rates improved, from 0.68 (95% CI 0.64-0.71) to 0.75 (95% CI 0.72-0.78); a difference of 0.076 (95% CI 0.03-0.12) (p = 0.001). Intubation success rates in the pre-intervention and post-intervention periods were found to be static. A significant decrease was found in the number of attempts per patient in the post-period (p = 0.005). Conclusion Intubation success increased from 68% to 75% and was maintained over the 12-month post-period. There is a potential that judgment may also have improved, based on the decreased number of attempts per patient. Limitations include missing values, paramedics' self-reported number of attempts, and the definition of what is considered to be an attempt. In addition to previously demonstrated improvements in paramedic exam and scenario performance, this airway education intervention appears to have made a significant improvement to patient outcomes. These findings support the value of such education interventions to improve performance.

Providing palliative care at home aligns with the professional identity of paramedics: a qualitative study of paramedics and palliative health care providers.

BACKGROUND: An innovative program, 'Paramedics Providing Palliative Care at Home,' was implemented in Nova Scotia, Canada in 2015. Roles like this are part of an evolving professional identity; role discordance or lack of clarity not only hinders professionalization but may impair the wellbeing, and career longevity of paramedics. This study explored the alignment of providing palliative support at home with paramedic professional identity. METHODS: Qualitative description was employed, with thematic analysis of focus groups with paramedics and palliative health care providers. Recruitment posters were sent through the professional college (paramedics) and program managers (health care providers). Focus groups followed a semi-structured guide, discussing understanding of and experiences with the role and its alignment with professional identity. Challenges to paramedic palliative support and fit with professional identify were explored. Thematic content analysis was ongoing while focus groups were being conducted, until no new codes were found. Codes were combined, sorted into categories, and ultimately, agreed-upon themes. Saturation of themes was reached. RESULTS: Eleven paramedics and twenty palliative health care providers participated. Four themes reflected paramedic's expanded role: (1) patient centeredness and job satisfaction with provision of palliative support, (2) a bridging role, (3) paramedic as advocate and educator, (4) provision of psychosocial support. Four themes reflected paramedic's professional identity: (1) evolution of paramedicine as a skilled clinical profession, (2) helping people and communities, (3) paramedic skill set aligns with work in palliative care, and (4) changing paramedic mindset. CONCLUSION: Paramedics and palliative health care providers highlighted the provision of palliative care as part of a positive growth of paramedicine as a health profession, and a good fit with professional identity. Novel roles like this are important in the evolution of our health care system faced with increasing pressures to get the right care with the right provider at the right time.

RéSUMé: CONTEXTE: Un programme innovant, " Programme de soins palliatifs paramédicaux à domicile ", a été mis en œuvre en Nouvelle-Écosse, au Canada, en 2015. Les rôles de ce type font partie d'une identité professionnelle en évolution ; la discordance ou le manque de clarté des rôles non seulement entrave la professionnalisation, mais peut aussi nuire au bien-être et à la longévité de la carrière des ambulanciers paramédicaux. Cette étude a exploré l'alignement de la prestation de soutien palliatifs à domicile avec l'identité professionnelle des ambulanciers paramédicaux. MéTHODES: Une description qualitative a été employée, avec une analyse thématique de groupes de discussion avec des ambulanciers paramédicaux et des prestataires de soins palliatifs. Des affiches de recrutement ont été envoyées par le biais du collège professionnel (paramédicaux) et des gestionnaires de programmes (prestataires de soins de santé). Les groupes de discussion ont suivi un guide semi-structuré, discutant de la compréhension et des expériences du rôle et de son alignement avec l'identité professionnelle. Les défis du soutien palliatif paramédical et son adéquation avec l'identité professionnelle ont été explorés. L'analyse du contenu thématique s'est poursuivie pendant la tenue des groupes de discussion, jusqu'à ce qu'aucun nouveau code ne soit trouvé. Les codes ont été combinés, triés en catégories et, finalement, en thèmes convenus. La saturation des thèmes a été atteinte. RéSULTATS: Onze ambulanciers paramédicaux et vingt prestataires de soins palliatifs ont participé. Quatre thèmes reflétaient le rôle élargi des ambulanciers paramédicaux : 1) l'orientation vers le patient et la satisfaction professionnelle à l'égard de la prestation de soutien palliatifs, 2) un rôle de transition, 3) les ambulanciers paramédicaux à titre de défenseurs et d'éducateurs, 4) un soutien psychosocial. Quatre thèmes reflétaient l'identité professionnelle des ambulanciers paramédicaux : 1) l'évolution de la profession paramédicale en tant que profession clinique qualifiée, 2) l'aide aux personnes et aux collectivités, 3) l'ensemble des compétences des ambulanciers paramédicaux s'harmonise avec le travail en soins palliatifs, et 4) l'évolution de l'état d'esprit des ambulanciers paramédicaux. CONCLUSION: Les ambulanciers paramédicaux et les prestataires de soins palliatifs ont souligné que la prestation de soins palliatifs faisait partie d'une croissance positive de la profession paramédicale en tant que profession de la santé et correspondait bien à l'identité professionnelle. Des rôles novateurs comme celui-ci sont importants dans l'évolution de notre système de soins de santé, confronté à des pressions croissantes pour obtenir les bons soins auprès du bon prestataire au bon moment.

Controlling neural territory patterning from pluripotency using a systems developmental biology approach.

Successful manufacture of specialized human cells requires process understanding of directed differentiation. Here, we apply high-dimensional Design of Experiments (HD-DoE) methodology to identify critical process parameters (CPPs) that govern neural territory patterning from pluripotency-the first stage toward specification of central nervous system (CNS) cell fates. Using computerized experimental design, 7 developmental signaling pathways were simultaneously perturbed in human pluripotent stem cell culture. Regionally specific genes spanning the anterior-posterior and dorsal-ventral axes of the developing embryo were measured after 3 days and mathematical models describing pathway control were developed using regression analysis. High-dimensional models revealed particular combinations of signaling inputs that induce expression profiles consistent with emerging CNS territories and defined CPPs for anterior and posterior neuroectoderm patterning. The results demonstrate the importance of combinatorial control during neural induction and challenge the use of generic neural induction strategies such as dual-SMAD inhibition, when seeking to specify particular lineages from pluripotency.

A Neural Network Approach for Property Determination of Molecular Solar Cell Candidates.

The dihydroazulene/vinylheptafulvene (DHA/VHF) photocouple is a promising candidate for molecular solar heat batteries, storing and releasing energy in a closed cycle. Much work has been done on improving the energy storage capacity and the half-life of the high-energy isomer via substituent functionalization, but similarly important is keeping these improved properties in common polar solvents, along with being soluble in these, which is tied to the dipole properties. However, the number of possible derivatives makes an overview of this combinatorial space impossible both for experimental work and traditional computational chemistry. Due to the time-consuming nature of running many thousands of computations, we look to machine learning, which bears the advantage that once a model has been trained, it can be used to rapidly estimate approximate values for the given system. Applying a convolutional neural network, we show that it is possible to reach good agreement with traditional computations on a scale that allows us to rapidly screen tens of thousands of the DHA/VHF photocouple, eliminating bad candidates and allowing computational resources to be directed toward meaningful compounds.

Substituent Control of σ-Interference Effects in the Transmission of Saturated Molecules.

The single-molecule conductance of saturated molecules can potentially be fully suppressed by destructive quantum interference in their σ-system. However, only few molecules with σ-interference have been identified, and the structure-property relationship remains to be elucidated. Here, we explore the role of substituents in modulating the electronic transmission of saturated molecules. In functionalized bicyclo[2.2.2]octanes, the transmission is suppressed by σ-interference when fluorine substituents are applied. For bicyclo[2.2.2]octasilane and -octagermanes, the transmission is suppressed when carbon-based substituents are used, and such molecules are likely to be highly insulating. For the carbon-based substituents, we find a strong correlation between the appropriate Hammett constants and the transmission. The substituent effect enables systematic optimization of the insulating properties of saturated molecular cores.

Virtual screening of norbornadiene-based molecular solar thermal energy storage systems using a genetic algorithm.

We present a computational methodology for the screening of a chemical space of 1025 substituted norbornadiene molecules for promising kinetically stable molecular solar thermal (MOST) energy storage systems with high energy densities that absorb in the visible part of the solar spectrum. We use semiempirical tight-binding methods to construct a dataset of nearly 34 000 molecules and train graph convolutional networks to predict energy densities, kinetic stability, and absorption spectra and then use the models together with a genetic algorithm to search the chemical space for promising MOST energy storage systems. We identify 15 kinetically stable molecules, five of which have energy densities greater than 0.45 MJ/kg, and the main conclusion of this study is that the largest energy density that can be obtained for a single norbornadiene moiety with the substituents considered here, while maintaining a long half-life and absorption in the visible spectrum, is around 0.55 MJ/kg.

The repetitive application of cold atmospheric plasma (CAP) improves microcirculation parameters in chronic wounds.

BACKGROUND: Chronic wounds, such as venous leg ulcers, diabetic foot ulcers, and pressure ulcers, impose a significant burden on patients and health care systems worldwide. Cold atmospheric plasma (CAP) accelerates wound healing and decreases bacterial load in chronic wounds in both in vitro and in vivo experiments. For the first time, we examined the effects of a repetitive application of CAP on the microcirculation in chronic wounds. HYPOTHESIS: The repetitive application of cold atmospheric plasma application further improves microcirculation in chronic wounds. METHODS: Twenty patients with chronic wounds were treated repetitively with CAP. The repetitive application consisted of three CAP sessions, each lasting 90 s and separated by a 10-minute microcirculation measuring period. Microcirculation parameters were assessed with combined Laser-Doppler-Flowmetry and spectrophotometry in a tissue depth of 2 mm. RESULTS: Tissue oxygen saturation was significantly increased after the first CAP application. The effect amplitude and duration were further increased after the second and third CAP application with a maximum increase by 16,7% (percent change; p = 0,004 vs. baseline) after the third application. There was no significant increase in capillary blood flow until the third CAP application. After the third CAP application, an increase by 22,6% (p = 0,014) was observed. Postcapillary filling pressure was not significantly increased over the measuring period. The repetitive application of CAP further enhances the microcirculation in chronic wounds compared to a single application. CONCLUSION: The repetitive application of CAP boosts and prolongs tissue oxygen saturation and capillary blood flow in chronic wounds compared to a single application. This insight could provide an impetus for new treatment protocols.