Inhibition and reversal of a TGF-ß1 induced myofibroblast phenotype by adipose tissue-derived paracrine factors.

BACKGROUND: Hypertrophic scarring results from myofibroblast differentiation and persistence during wound healing. Currently no effective treatment for hypertrophic scarring exists however, autologous fat grafting has been shown to improve scar elasticity, appearance, and function. The aim of this study was to understand how paracrine factors from adipose tissues and adipose-derived stromal cells (ADSC) affect fibroblast to myofibroblast differentiation. METHODS: The transforming growth factor-ß1 (TGF-ß1) induced model of myofibroblast differentiation was used to test the effect of conditioned media from adipose tissue, ADSC or lipid on the proportion of fibroblasts and myofibroblasts. RESULTS: Adipose tissue conditioned media inhibited the differentiation of fibroblasts to myofibroblasts but this inhibition was not observed following treatment with ADSC or lipid conditioned media. Hepatocyte growth factor (HGF) was readily detected in the conditioned medium from adipose tissue but not ADSC. Cells treated with HGF, or fortinib to block HGF, demonstrated that HGF was not responsible for the inhibition of myofibroblast differentiation. Conditioned media from adipose tissue was shown to reduce the proportion of myofibroblasts when added to fibroblasts previously treated with TGF-ß1, however, conditioned media treatment was unable to significantly reduce the proportion of myofibroblasts in cell populations isolated from scar tissue. CONCLUSIONS: Cultured ADSC or adipocytes have been the focus of most studies, however, this work highlights the importance of considering whole adipose tissue to further our understanding of fat grafting. This study supports the use of autologous fat grafts for scar treatment and highlights the need for further investigation to determine the mechanism.

A Development and Implementation of a Preconception Counseling Program for Black Women and Men in the Southeastern United States: A Pilot Protocol.

Introduction: Racial/ethnic disparities in maternal mortality rates represent one of the most significant areas of disparities amongst all conventional population perinatal health measures in the U.S. The alarming trends and persistent disparities of outcomes by race/ethnicity and geographic location reinforce the need to focus on ensuring quality and safety of maternity care for all women. Despite complex multilevel factors impacting maternal mortality and morbidity, there are evidence-based interventions that, when facilitated consistently and properly, are known to improve the health of mothers before, during and after pregnancy. The objective of this project is to test implementation of pre-conception counseling with father involvement in community-based settings to improve cardiovascular health outcomes before and during pregnancy in southeastern United States. Methods and Analysis: This study has two components: a comprehensive needs and assets assessment and a small-scale pilot study. We will conduct a community informed needs and assets assessment with our diverse stakeholders to identify opportunities and barriers to preconception counseling as well as develop a stakeholder-informed implementation plan. Next, we will use the implementation plan to pilot preconception counseling with father involvement in community-based settings. Finally, we will critically assess the context, identify potential barriers and facilitators, and iteratively adapt the way preconception counseling can be implemented in diverse settings. Results of this research will support future research focused on identifying barriers and opportunities for scalable and sustainable public health approaches to implementing evidence-based strategies that reduce maternal morbidity and mortality in the southeastern United States' vulnerable communities. Discussion: Findings will demonstrate that preconception counseling can be implemented in community health settings in the southeastern United States. Furthermore, this study will build the capacity of community-based organizations in addressing the preconception health of their clients. We plan for this pilot to inform a larger scaled-up clinical trial across community health settings in multiple southeastern states.

Evaluation of the NHS England 'Op COURAGE' High Intensity Service for military veterans with significant mental health problems.

INTRODUCTION: In November 2020, The NHS for England launched a pilot High Intensity Service (HIS) programme for treating military veterans complex mental health problems. Seven regional grants were awarded to manage the HIS, including NHS Solent, in South East England. This paper details an evaluation of the HIS, which was conducted from February 2021 to August 2022. METHODS: This mixed-methods study gained quantitative data from a specifically designed questionnaire that included a number of validated psychometric questionnaires. These were completed by either HIS staff or beneficiaries at entry and exit from the HIS, and qualitative data were gained from semi-structured interviews with the HIS staff. RESULTS: Data were sourced from 45 pre-questionnaires, 25 post programme questionnaires and 11 interviews. This evaluation identified reductions in situational stressors, symptoms and reported illnesses for veterans in crisis. There were reductions in depression, anxiety and post-traumatic stress disorder following programme exit. Staff reported that there was no notable changes in stress levels which appeared to remain high at programme exit. Staff interviews highlighted the importance of simultaneously understanding the social and psychological needs of veterans in mental health crisis. The benefits of integrating veteran staff members into military veteran health services were identified, demonstrating improvements in education around military culture in civilian services. CONCLUSIONS: The importance of collaboration between clinical and veteran staff members in veteran health services was noted, demonstrating the positive impact social care provision has on veteran's overall health and well-being. Veteran engagement with the service was advocated as a result of veterans accessing the service feeling understood. This first independent evaluation of the HIS provides a positive reflection, and adds to the limited empirical evidence exploring veteran engagement in health services.

Prevalence and risk factors of suicide and suicidal ideation in veterans who served in the British Armed Forces: a systematic review.

INTRODUCTION: Research into the factors resulting in suicide in the military veteran population has yet to reach a consensus. Available research is concentrated on a small number of countries, and there is a lack of consistency with contradictory conclusions. The USA has produced a significant amount of research in a country where suicide is identified as a national health crisis, but in the UK, there is little research regarding veterans from the British Armed Forces. METHODS: This systematic review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Corresponding literature searches were conducted in PsychINFO, MEDLINE and CINAHL. Articles that discussed suicide, suicidal ideation, prevalence or risk factors among British Armed Forces veterans were eligible for review. A total of 10 articles met the inclusion criteria and were analysed. RESULTS: Veterans' suicide rates were found to be comparable to those of the general UK population. The method of suicide used was most commonly found to be hanging and strangulation. Firearms was recorded in 2% of suicide cases. Demographic risk factors were often contradictory with some research stating that there was risk in older veterans and some in younger. However, female veterans were found to be at higher risk than female civilians. Those who had deployed on combat operations were at lower risk of suicide, with research finding that veterans who took longer to seek help for mental health (MH) difficulties reported more suicidal ideation. CONCLUSIONS: Peer-reviewed research publications have revealed that UK veteran suicide prevalence is broadly comparable to the general population while highlighting differences across international armed forces. Veteran demographics, service history, transition and MH have all been identified as potential risk factors of suicide and suicidal ideation. Research has also indicated that female veterans are at higher risk than that of their civilian counterparts due to veterans being predominantly male; this could skew results and requires investigation. Current research is limited and further exploration of suicide prevalence and risk factors in the UK veteran population is required.

Phenotyping Superagers Using Resting-State fMRI.

BACKGROUND AND PURPOSE: Superagers are defined as older adults with episodic memory performance similar or superior to that in middle-aged adults. This study aimed to investigate the key differences in discriminative networks and their main nodes between superagers and cognitively average elderly controls. In addition, we sought to explore differences in sensitivity in detecting these functional activities across the networks at 3T and 7T MR imaging fields. MATERIALS AND METHODS: Fifty-five subjects 80 years of age or older were screened using a detailed neuropsychological protocol, and 31 participants, comprising 14 superagers and 17 cognitively average elderly controls, were included for analysis. Participants underwent resting-state-fMRI at 3T and 7T MR imaging. A prediction classification algorithm using a penalized regression model on the measurements of the network was used to calculate the probabilities of a healthy older adult being a superager. Additionally, ORs quantified the influence of each node across preselected networks. RESULTS: The key networks that differentiated superagers and elderly controls were the default mode, salience, and language networks. The most discriminative nodes (ORs > 1) in superagers encompassed areas in the precuneus posterior cingulate cortex, prefrontal cortex, temporoparietal junction, temporal pole, extrastriate superior cortex, and insula. The prediction classification model for being a superager showed better performance using the 7T compared with 3T resting-state-fMRI data set. CONCLUSIONS: Our findings suggest that the functional connectivity in the default mode, salience, and language networks can provide potential imaging biomarkers for predicting superagers. The 7T field holds promise for the most appropriate study setting to accurately detect the functional connectivity patterns in superagers.

The Sickle Cell Pro-Inflammatory Response to Interval Testing Study (SPRINTS) in children and young adults with sickle cell anemia - Study design and methodological strategies.

The impact of sickle cell anemia (SCA) and its complications on physical functioning and cardiopulmonary/aerobic fitness in affected individuals is significant. Although limited data support the safety of maximal cardiopulmonary exercise testing (CPET) for children and adults with SCA, the safety of submaximal moderate and high intensity, and longer duration, exercise in this population is not clear. The Sickle Cell Pro-Inflammatory Response to Interval Testing Study (SPRINTS) is a multicenter, randomized, prospective trial. SPRINTS leverages unique collaborations between investigators in pediatric hematology and exercise science to evaluate the impact of exercise intensity on the acute phase inflammatory response to exercise and changes in airway dynamics in children and young adults with SCA. Here we describe the study design and methodological strategies employed in SPRINTS, including an exercise challenge that mimics real-life patterns of childhood physical activity, characterized by multiple moderate and high intensity brief bouts of exercise interspersed with rest periods. Primary outcomes comprise pre- and post-exercise biomarkers of inflammation and endothelial dysfunction and spirometry. Secondary outcomes include assessment of physical activity and functioning, genomic studies and near-infrared spectroscopy measurements to assess tissue oxygenation status during exercise. SPRINTS aims to enroll 70 subjects with SCA and 70 matched, healthy controls. We anticipate that data from SPRINTS will address gaps in our understanding of exercise responses and safety in SCA and support the future development of evidence-based, exercise prescription guidelines in this population.

The clinical significance of a pathologically positive lymph node at the circumferential resection margin in rectal cancer.

BACKGROUND: This study aimed to determine if the nature of circumferential resection margin (CRM) involvement, either by tumour or lymph nodes, had an impact upon local recurrence and survival in rectal cancer. METHODS: A retrospective analysis of a prospectively collected database was performed. Consecutive patients with stage I-III rectal cancer having curative surgery were included. All specimens were analysed by a single histopathologist. Statistical analysis was performed using chi-squared test and Kaplan-Meier. RESULTS: Of 265 patients, 29 (11%) had a positive CRM. Compared to patients with a negative CRM, a positive margin due to tumour was associated with a higher 5-year cumulative incidence of local recurrence (43.7% versus 8.8%, p = 0.001) and distant metastases (62% versus 13.6%, p = 0.001) with poorer 5-year cancer-specific survival (32% versus 87.8%, p = 0.001). Although patients with margin positivity due to lymph nodes had a higher rate of distant metastases (41.3% versus 13.6%, p = 0.004) and poorer 5-year cancer-specific survival (59.3% versus 87.8%, p = 0.038), the rate of local recurrence was comparable to that of patients with negative margins (8.3% versus 8.8%, p = 0.694). CONCLUSIONS: Our findings suggest that the nature of CRM involvement may be important in determining prognosis in rectal cancer. Local recurrence is higher only when there is tumour present at the margin. Lymph node involvement of the margin confers similar risk of local recurrence to patients with CRM-negative, node-positive disease. These results need further evaluation in multicentre, prospective studies.

Benefits of introduction of Oncotype DX® testing.

INTRODUCTION: Decisions regarding adjuvant chemotherapy in women with oestrogen receptor positive, human epidermal growth factor receptor 2 negative, node negative, early invasive breast cancer are unclear. The Recurrence Score® (RS) from Oncotype DX® (ODX) testing guides decisions based on individual cancer genomics. The aim of this study was to evaluate the impact of introducing ODX results on adjuvant treatment decisions and its potential economic benefits. METHODS: Patients offered the test were identified from the ODX requesting system. Information on reasons behind chemotherapy treatment decisions were collected from clinical letters and the pathology system. The Nottingham prognostic index (NPI) scores were calculated for each individual patient. RESULTS: A total of 101 patients were identified as having undergone ODX testing over 21 months. The median age was 57 years (range: 41-72 years), the median NPI was 3.70 (range: 3.40-5.26) and the median RS was 17 (range: 0-59). NPI did not predict the risk category. All of the patients in the high risk group, 35.1% in the intermediate risk group and 5.4% in the low risk group received chemotherapy. The majority of low risk patients who received chemotherapy made a decision prior to the ODX result. CONCLUSIONS: In our unit, RS aided our decision making regarding adjuvant chemotherapy. Patients with a higher RS were more likely to receive chemotherapy. If NPI had been used alone, more women would have been offered chemotherapy. Good communication with patients prior to testing is important to ensure it is cost effective.

Methods for the Simulation of the Slowing of Low-Energy Electrons in Water.

A computational Monte Carlo simulation approach for modeling the thermalization of low-energy electrons is presented. The simulation methods rely on, and use, experimentally based cross sections for elastic and inelastic collisions. To demonstrate the different simulation options, average numbers of interactions and the range of low-energy electrons with initial energies ranging from 1 to 20 eV are calculated for density normalized gaseous water. Experimental gas-phase cross sections for (subexcitation) electrons of energies in the range of 1-20 eV were taken from the compilation of Hayashi. The ballistic collision-by-collision simulations provide information on the intricacies of the thermalization processes not available experimentally. © 2018 Wiley Periodicals, Inc.

Molecular dynamics simulation of potentiometric sensor response: the effect of biomolecules, surface morphology and surface charge.

The silica-water interface is critical to many modern technologies in chemical engineering and biosensing. One technology used commonly in biosensors, the potentiometric sensor, operates by measuring the changes in electric potential due to changes in the interfacial electric field. Predictive modelling of this response caused by surface binding of biomolecules remains highly challenging. In this work, through the most extensive molecular dynamics simulation of the silica-water interfacial potential and electric field to date, we report a novel prediction and explanation of the effects of nano-morphology on sensor response. Amorphous silica demonstrated a larger potentiometric response than an equivalent crystalline silica model due to increased sodium adsorption, in agreement with experiments showing improved sensor response with nano-texturing. We provide proof-of-concept that molecular dynamics can be used as a complementary tool for potentiometric biosensor response prediction. Effects that are conventionally neglected, such as surface morphology, water polarisation, biomolecule dynamics and finite-size effects, are explicitly modelled.

Bayesian evidence and epidemiological implications of environmental contamination from acute respiratory infection in long-term care facilities.

Skilled nursing home facilities (SNFs) house a vulnerable population frequently exposed to respiratory pathogens. Our study aims to gain a better understanding of the transmission of nursing home-acquired viral respiratory infections in non-epidemic settings. Symptomatic surveillance was performed in three SNFs for residents exhibiting acute respiratory symptoms. Environmental surveillance of five high-touch areas was performed to assess possible transmission. All resident and environmental samples were screened using a commercial multiplex polymerase chain reaction platform. Bayesian methods were used to evaluate environmental contamination. Among nursing home residents with respiratory symptoms, 19% had a detectable viral pathogen (parainfluenza-3, rhinovirus/enterovirus, RSV, or influenza B). Environmental contamination was found in 20% of total room surface swabs of symptomatic residents. Environmental and resident results were all concordant. Target period prevalence among symptomatic residents ranged from 5.5 to 13.3% depending on target. Bayesian analysis quantifies the probability of environmental shedding due to parainfluenza-3 as 92.4% (95% CI: 86.8-95.8%) and due to rhinovirus/enterovirus as 65.6% (95% CI: 57.9-72.5%). Our findings confirm that non-epidemic viral infections are common among SNF residents exhibiting acute respiratory symptoms and that environmental contamination may facilitate further spread with considerable epidemiological implications. Findings further emphasise the importance of environmental infection control for viral respiratory pathogens in long-term care facilities.

Identification of Berenil Target Sites in Plasmid pBR322.

Berenil, a minor groove DNA binding molecule, has been extensively used in veterinary medicine. Modeling studies have suggested that berenil binds to A/T rich regions on the DNA and the product of this interaction causes the formation of crosslinks between opposite DNA strands. These crosslinks could potentially inhibit fundamental biological processes including transcription and DNA replication. We had previously used the pBR322 genome as a model system to investigate the role of A/T sequences on berenil activity. We reported that the insertion of poly(dA)poly(dT) sequences into the pBR322 genome causes replication inhibition of the recombinant plasmids when cultures were exposed to berenil. However, we noticed that even in the absence of these sequences the parental plasmid replication was also inhibited, albeit less than the recombinants. This observation led us to the present study were we attempted to identify the location of natural berenil target sites in the pBR322 genome. Through a combination of deletion analysis, recombinant DNA and a replication assay we uncovered a 378 bp DNA fragment that has all the hallmarks of a berenil target site. A recombinant plasmid lacking this region is more refractive to the drug than the parental plasmid, and another variant containing and extra copy of this region increases the susceptibility of the plasmid towards berenil. The 378 bp region is about 60% A/T rich and contains about 21 potential berenil binding sites.

Dynamic behaviour of the silica-water-bio electrical double layer in the presence of a divalent electrolyte.

Electronic devices are becoming increasingly used in chemical- and bio-sensing applications and therefore understanding the silica-electrolyte interface at the atomic scale is becoming increasingly important. For example, field-effect biosensors (BioFETs) operate by measuring perturbations in the electric field produced by the electrical double layer due to biomolecules binding on the surface. In this paper, explicit-solvent atomistic calculations of this electric field are presented and the structure and dynamics of the interface are investigated in different ionic strengths using molecular dynamics simulations. Novel results from simulation of the addition of DNA molecules and divalent ions are also presented, the latter of particular importance in both physiological solutions and biosensing experiments. The simulations demonstrated evidence of charge inversion, which is known to occur experimentally for divalent electrolyte systems. A strong interaction between ions and DNA phosphate groups was demonstrated in mixed electrolyte solutions, which are relevant to experimental observations of device sensitivity in the literature. The bound DNA resulted in local changes to the electric field at the surface; however, the spatial- and temporal-mean electric field showed no significant change. This result is explained by strong screening resulting from a combination of strongly polarised water and a compact layer of counterions around the DNA and silica surface. This work suggests that the saturation of the Stern layer is an important factor in determining BioFET response to increased salt concentration and provides novel insight into the interplay between ions and the EDL.

Pseudomonas aeruginosa Induced Airway Epithelial Injury Drives Fibroblast Activation: A Mechanism in Chronic Lung Allograft Dysfunction.

Bacterial infections after lung transplantation cause airway epithelial injury and are associated with an increased risk of developing bronchiolitis obliterans syndrome. The damaged epithelium is a source of alarmins that activate the innate immune system, yet their ability to activate fibroblasts in the development of bronchiolitis obliterans syndrome has not been evaluated. Two epithelial alarmins were measured longitudinally in bronchoalveolar lavages from lung transplant recipients who developed bronchiolitis obliterans syndrome and were compared to stable controls. In addition, conditioned media from human airway epithelial cells infected with Pseudomonas aeruginosa was applied to lung fibroblasts and inflammatory responses were determined. Interleukin-1 alpha (IL-1α) was increased in bronchoalveolar lavage of lung transplant recipients growing P. aeruginosa (11.5 [5.4-21.8] vs. 2.8 [0.9-9.4] pg/mL, p < 0.01) and was significantly elevated within 3 months of developing bronchiolitis obliterans syndrome (8.3 [1.4-25.1] vs. 3.6 [0.6-17.1] pg/mL, p < 0.01), whereas high mobility group protein B1 remained unchanged. IL-1α positively correlated with elevated bronchoalveolar lavage IL-8 levels (r(2)  = 0.6095, p < 0.0001) and neutrophil percentage (r(2)  = 0.25, p = 0.01). Conditioned media from P. aeruginosa infected epithelial cells induced a potent pro-inflammatory phenotype in fibroblasts via an IL-1α/IL-1R-dependent signaling pathway. In conclusion, we propose that IL-1α may be a novel therapeutic target to limit Pseudomonas associated allograft injury after lung transplantation.

The management of acute hip pain in the military: femoral neck stress fractures and tears of the acetabular labrum.

Acute hip pain is a common presenting complaint amongst the military population. It can present in a variety of ways, with a broad range of differential diagnoses to consider. Most cases of acute hip pain in military patients tend to be traumatic in origin. Pathology within the hip can be a diagnostic challenge, as symptoms often overlap between differential diagnoses and examination findings are not always sensitive or specific. Any hip injury will potentially downgrade a military patient and can also be a significant cause of long-term morbidity. Being able to manage the patient with acute hip pain effectively will ensure that patients spend less time in the diagnostic chain and reach the definitive treatment they require to continue to carry out their primary role. This paper describes how best to manage military patients who present with acute hip pain. It covers the diagnostic challenges faced by clinicians, the differential diagnoses of acute hip pain and describes the management of some common injuries of the hip: tears of the acetabular labrum and femoral neck stress fractures.

Quantifying the Burden of Hospital-Acquired Bloodstream Infection in Children in England by Estimating Excess Length of Hospital Stay and Mortality Using a Multistate Analysis of Linked, Routinely Collected Data.

BACKGROUND: Hospital-acquired bloodstream infection (HA-BSI) is associated with substantial morbidity, mortality, and healthcare costs in all patient populations. Young children have been shown to have a high rate of healthcare-associated infections compared with the adult population. We aimed to quantify the excess mortality and length of stay in pediatric patients from HA-BSI. METHODS: We analyzed data collected retrospectively from a probabilistically linked national database of pediatric (aged 1 month-18 years) in-patients with a microbiologically confirmed HA-BSI in England between January and March 2009. A time-dependent Cox regression model was fit to determine the presence of any effect. Furthermore, a multistate model, adjusted for the time to onset of HA-BSI, was used to compare outcomes in patients with HA-BSI to those without HA-BSI. We further adjusted for patients' characteristics as recorded in hospital admission data. RESULTS: The dataset comprised 333 605 patients, with 214 cases of HA-BSI. After adjustment for time to HA-BSI and comorbidities, the hazard for discharge (dead or alive) from hospital for patients with HA-BSI was 0.9 times (95% confidence interval [CI], .8-1.1) that of noninfected patients. Excess length of stay associated with all-cause HA-BSI was 1.6 days (95% CI, .2-3.0), although this duration varied by pathogen. Patients with HA-BSI had a 3.6 (95% CI, 1.3-10.4) times higher hazard for in-hospital death than noninfected patients. CONCLUSIONS: Hospital-acquired bloodstream infection increased the length of stay and mortality of pediatric inpatients. The results of this study provide an evidence base to judge the health and economic impact of programs to prevent and control HA-BSI in children.

Outcome after conservatively managed intracapsular fractures of the femoral neck.

INTRODUCTION: In 2012, 2.6% of hip-fracture patients in the UK were treated conservatively. There is little data on outcome for these patients. However, one study demonstrated that though 30-day mortality is higher, mortality over the rest of the year is comparable with that in surgical groups. Therefore, we assessed conservatively managed patients in our unit. METHODS: Patients with intracapsular fractures of the femoral neck treated by conservative means between 2010 and 2012 inclusive were identified. Data were collected: American Society of Anaesthesiologists (ASA) grade, Nottingham Hip Fracture Score (NHFS), mobility, mortality (30 days and one year) and pain levels. RESULTS: Thirty-two patients formed the study cohort. Mean age was 85.6 years. Median ASA grade was 4. Mortality at 30 days and one year was 31.3% and 56.3%, respectively. There was one case of pneumonia and one of infection. Pressure sores or venous thromboembolism were not documented. Three patients underwent surgery once their health improved. In general, mobility was decreased, but 30.8% of patients could mobilise with two aids or a frame. Only two cases had ongoing problems with pain. CONCLUSIONS: Our data are similar to those published previously. Our patients were likely to have higher mortality data due to selection bias. Thirty-day mortality was significantly higher than the national average, but patients surviving 30 days had a prevalence of mortality similar to those managed by surgical means. Despite mobility decreasing from the pre-admission status, a considerable number of patients were free of pain and could mobilise. These data suggest that conservative management of intracapsular fractures of the femoral neck can produce acceptable results.

Reanalysis of Rate Data for the Reaction CH3 + CH3 → C2H6 Using Revised Cross Sections and a Linearized Second-Order Master Equation.

Rate coefficients for the CH3 + CH3 reaction, over the temperature range 300-900 K, have been corrected for errors in the absorption coefficients used in the original publication ( Slagle et al., J. Phys. Chem. 1988 , 92 , 2455 - 2462 ). These corrections necessitated the development of a detailed model of the B̃(2)A1' (3s)-X̃(2)A2″ transition in CH3 and its validation against both low temperature and high temperature experimental absorption cross sections. A master equation (ME) model was developed, using a local linearization of the second-order decay, which allows the use of standard matrix diagonalization methods for the determination of the rate coefficients for CH3 + CH3. The ME model utilized inverse Laplace transformation to link the microcanonical rate constants for dissociation of C2H6 to the limiting high pressure rate coefficient for association, k∞(T); it was used to fit the experimental rate coefficients using the Levenberg-Marquardt algorithm to minimize χ(2) calculated from the differences between experimental and calculated rate coefficients. Parameters for both k∞(T) and for energy transfer ⟨ΔE⟩down(T) were varied and optimized in the fitting procedure. A wide range of experimental data were fitted, covering the temperature range 300-2000 K. A high pressure limit of k∞(T) = 5.76 × 10(-11)(T/298 K)(-0.34) cm(3) molecule(-1) s(-1) was obtained, which agrees well with the best available theoretical expression.