Compound-Nucleus and Doorway-State Decays of ß-Delayed Neutron Emitters

We investigated decays of ^{51,52,53}K at the ISOLDE Decay Station at CERN in order to understand the mechanism of the ß-delayed neutron-emission (ßn) process. The experiment quantified neutron and γ-ray emission paths for each precursor. We used this information to test the hypothesis, first formulated by Bohr in 1939, that neutrons in the ßn process originate from the structureless "compound nucleus." The data are consistent with this postulate for most of the observed decay paths. The agreement, however, is surprising because the compound-nucleus stage should not be achieved in the studied ß decay due to insufficient excitation energy and level densities in the neutron emitter. In the ^{53}K ßn decay, we found a preferential population of the first excited state in ^{52}Ca that contradicted Bohr's hypothesis. The latter was interpreted as evidence for direct neutron emission sensitive to the structure of the neutron-unbound state. We propose that the observed nonstatistical neutron emission proceeds through the coupling with nearby doorway states that have large neutron-emission probabilities. The appearance of "compound-nucleus" decay is caused by the aggregated small contributions of multiple doorway states at higher excitation energy.

Old known and possible new biomarkers of ANCA-associated vasculitis.

Antineutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV) comprises a group of multisystem disorders involving severe, systemic, small-vessel vasculitis with short- and long term serious and life-threating complications. Despite the simplification of treatment, fundamental aspects concerning assessment of its efficacy and its adaptation to encountered complications or to the relapsing/remitting/subclinical disease course remain still unknown. The pathogenesis of AAV is complex and unique, and despite the progress achieved in the last years, much has not to be learnt. Foremost, there is still no accurate marker enabling us to monitoring disease and guide therapy. Therefore, the disease management relays often on clinical judgment and follows a" trial and error approach". In the recent years, an increasing number of new molecules s have been explored and used for this purpose including genomics, B- and T-cell subpopulations, complement system factors, cytokines, metabolomics, biospectroscopy and components of our microbiome. The aim of this review is to discuss both the role of known historical and clinically established biomarkers of AAV, as well as to highlight potential new ones, which could be used for timely diagnosis and monitoring of this devastating disease, with the goal to improve the effectiveness and ameliorate the complications of its demanding therapy.

Early Signal of Emerging Nuclear Collectivity in Neutron-Rich

Radioactive ^{129}Sb, which can be treated as a proton plus semimagic ^{128}Sn core within the particle-core coupling scheme, was studied by Coulomb excitation. Reduced electric quadrupole transition probabilities, B(E2), for the 2^{+}⊗πg_{7/2} multiplet members and candidate πd_{5/2} state were measured. The results indicate that the total electric quadrupole strength of ^{129}Sb is a factor of 1.39(11) larger than the ^{128}Sn core, which is in stark contrast to the expectations of the empirically successful particle-core coupling scheme. Shell-model calculations performed with two different sets of nucleon-nucleon interactions suggest that this enhanced collectivity is due to constructive quadrupole coherence in the wave functions stemming from the proton-neutron residual interactions, where adding one nucleon to a core near a double-shell closure can have a pronounced effect. The enhanced electric quadrupole strength is an early signal of the emerging nuclear collectivity that becomes dominant away from the shell closure.

MCC950 blocks enhanced interleukin-1ß production in patients with NLRP3 low penetrance variants.

OBJECTIVE: To determine the role of the NLRP3 inflammasome by using the selective NLRP3 inhibitor MCC950 in patients with NLRP3 low penetrance variants and clinical symptoms suggestive for an autoinflammatory syndrome including central nervous system (CNS) involvement. METHODS: Nineteen symptomatic patients with low penetrance NLRP3 variants (Q703K n = 17, V198M n = 2) recruited between 2011 and 2017 were included in this monocentric study. A functional inflammasome activation assay was performed in patients in comparison to healthy controls (HC), including the determination of interleukin-1beta (IL-1ß), interleukin-6 (IL-6) and tumor-necrosis factor alpha (TNF-α) secretion in the presence of the NLRP3 selective small-molecule inhibitor MCC950. Detailed clinical features were assessed and anti-IL-1 treatment response was determined. RESULTS: Peripheral blood mononuclear cells (PBMC) from patients with low penetrance NLRP3 variants displayed enhanced IL-1ß levels following inflammasome activation compared to HC. Furthermore, IL-1ß release was NLRP3-dependent as it was blocked by MCC950. The production of IL-6 and TNF-α was also increased in patients with low penetrance NLRP3 variants. Clinically, they presented with a heterogenous spectrum of neurological manifestations, while cranial nerve inflammation was the most common feature. Overall inflammasome activation did not correlate with disease severity. Eight of ten treated patients responded to anti IL-1 treatment, however a complete response was only documented in four patients. CONCLUSION: PBMC of several patients with NLRP3 low penetrance variants and CNS manifestation showed increased NLRP3-specific IL-1ß release upon stimulation and elevated NLRP3-independent IL-6 and TNF-α levels as those were not suppressed by MCC950. Our data suggest that beside the possible causal involvement of the NLRP3 inflammasome additional, yet unidentified genetic or environmental factors may contribute to the multi-organ inflammation in our patients and explain the partial response to IL-1 targeting therapies.

Immunophenotyping of cerebrospinal fluid cells in ischaemic stroke.

BACKGROUND AND PURPOSE: Post-ischaemic immune cell invasion into the brain is well characterized in animal stroke models and contributes to neuronal damage. Therefore, it represents a promising therapeutic target. Cerebrospinal fluid (CSF) is easily accessible and may reflect cellular events within the parenchyma. However, comprehensive studies on CSF immune cells in patients with stroke are lacking. METHODS: In a retrospective cohort study, we performed extensive immune-cell profiling in CSF and peripheral blood of patients with acute ischaemic stroke and healthy controls. In patients with stroke, infarct size was quantified on follow-up imaging. RESULTS: Overall, 90 patients with ischaemic stroke and 22 controls were included in our study. After stroke, the total protein was increased (537.3 vs. 353.2 mg/L, P = 0.008) and the mean total white cell count was slightly but non-significantly elevated (1.76 vs. 0.50 cells/µL, P = 0.059). Proportions of CSF lymphocytes, monocytes and granulocytes and their respective subsets did not differ between patients with stroke and controls. In addition, there were no associations between proportions of major leukocyte subsets in CSF and the time from symptom onset to CSF sampling, infarct size or infarct localization. CONCLUSIONS: Ischaemic stroke induces only a very slight increase of CSF immune cells without changes in the composition of immune cell subsets, thus indicating that parenchymal inflammation is not sufficiently reflected in the CSF. Our findings suggest that CSF is not a major invasion route for immune cells and that CSF cell analyses are not suitable as biomarkers to guide future immune therapies for stroke.

[Chronic Disease Self-management Support for People with a Migrant Background: towards a Peer-led Group Program to Improve Equity in Health]. / Selbstmanagementförderung bei chronischer Krankheit für Menschen mit Migrationshintergrund ­ ein Gruppenkurs mit Peer-Ansatz als Beitrag zu gesundheitlicher Chancengerechtigkeit.

AIM: Limited health literacy and language skills are barriers for people with a migrant background (PMB) to access health information and healthcare services, in particular for those living with chronic conditions. During the introduction of a peer-led Stanford chronic disease self-management course in Switzerland, special interest in the program as well as motivation of PMB was observed. In response, we examined if the program can be implemented in German for people with limited language skills. METHODS: This explorative study is part of the evaluation study on introducing the adapted Stanford program in Switzerland and German-speaking Europe. Following the principles of Grounded Theory, semi-structured focus group and individual interviews were conducted with course participants, leaders and coordinators (n=30) and analyzed thematically. The focus was on the feasibility, satisfaction and course content. RESULTS: In principle, the program seems to have positive value for PMB, may work for them in German, have high relevance for everyday life and give an impetus for social integration. CONCLUSION: The need for and extent of modification of the program for PMB has to be further explored in order to make it more accessible for vulnerable groups.

[Longterm Homecare Augmentation Program in Alpha-1-Antitrypsin Deficient Patients]. / Langzeit-Augmentationstherapie von Patienten mit Alpha-1-Antitrypsin-Mangel in der häuslichen Pflege.

BACKGROUND: Augmentation with human alpha-1 proteinase inhibitor is the only specific treatment for Alpha-1-Antitrypsin Deficiency (AATD), a rare genetic disease with symptoms of progressive COPD. OBJECTIVES: A prospective long-term exploration of outcomes during the "Alpha-1-Mobile" home care AAT augmentation program in seven advanced-stage patients. METHODS: Patients received weekly i. v. AAT augmentation and COPD therapy. Symptoms, lung function, health status, quality-of-life aspects, and safety were documented continuously. Outcomes during six years of home care augmentation therapy were observed and evaluated on an inter- and intraindividual basis. FEV1 profiles were compared to pre-program data. RESULTS: The seven patients had a mean age of 56.7 (40-68) years and had previously received augmentation for 8.8 (1-19) years. Compared to the three-year preprogram period, functional decline of FEV1 (ΔFEV1 0.47 L vs 0.17 L) slowed. Mean QoL scores showed seasonal fluctuations in the first three years of observation, and then stabilized. All blood samples tested exceeded the protective threshold of 50 mg/dL with a dose of 60 mg AAT/kg/week. Less than one exacerbation-related hospitalization occurred per patient-year. No adverse events of related to augmentation therapy were observed. CONCLUSIONS: Home care with i. v. augmentation therapy by medical professionals contributes to optimum care through consistent treatment and close health-status monitoring in our collective. Exacerbation-related hospitalizations were largely avoided. "Alpha-1-Mobile" was well accepted, practical, and safe.

Electromagnetic Moments of Radioactive

Radioactive ^{136}Te has two valence protons and two valence neutrons outside of the ^{132}Sn double shell closure, providing a simple laboratory for exploring the emergence of collectivity and nucleon-nucleon interactions. Coulomb excitation of ^{136}Te on a titanium target was utilized to determine an extensive set of electromagnetic moments for the three lowest-lying states, including B(E2;0_{1}^{+}→2_{1}^{+}), Q(2_{1}^{+}), and g(2_{1}^{+}). The results indicate that the first-excited state, 2_{1}^{+}, composed of the simple 2p⊕2n system, is prolate deformed, and its wave function is dominated by excited valence neutron configurations, but not to the extent previously suggested. It is demonstrated that extreme sensitivity of g(2_{1}^{+}) to the proton and neutron contributions to the wave function provides unique insight into the nature of emerging collectivity, and g(2_{1}^{+}) was used to differentiate among several state-of-the-art theoretical calculations. Our results are best described by the most recent shell model calculations.

Impact of Modular Total Absorption Spectrometer measurements of ß decay of fission products on the decay heat and reactor ν[over ¯]_{e} flux calculation.

We report the results of a ß-decay study of fission products ^{86}Br, ^{89}Kr, ^{89}Rb, ^{90gs}Rb, ^{90m}Rb, ^{90}Kr, ^{92}Rb, ^{139}Xe, and ^{142}Cs performed with the Modular Total Absorption Spectrometer (MTAS) and on-line mass-separated ion beams. These radioactivities were assessed by the Nuclear Energy Agency as having high priority for decay heat analysis during a nuclear fuel cycle. We observe a substantial increase in ß feeding to high excited states in all daughter isotopes in comparison to earlier data. This increases the average γ-ray energy emitted by the decay of fission fragments during the first 10 000 s after fission of ^{235}U and ^{239}Pu by approximately 2% and 1%, respectively, improving agreement between results of calculations and direct observations. New MTAS results reduce the reference reactor ν[over ¯]_{e} flux used to analyze reactor ν[over ¯]_{e} interaction with detector matter. The reduction determined by the ab initio method for the four nuclear fuel components, ^{235}U, ^{238}U, ^{239}Pu, and ^{241}Pu, amounts to 0.976, 0.986, 0.983, and 0.984, respectively.

Atomic homodyne detection of continuous-variable entangled twin-atom states.

Historically, the completeness of quantum theory has been questioned using the concept of bipartite continuous-variable entanglement. The non-classical correlations (entanglement) between the two subsystems imply that the observables of one subsystem are determined by the measurement choice on the other, regardless of the distance between the subsystems. Nowadays, continuous-variable entanglement is regarded as an essential resource, allowing for quantum enhanced measurement resolution, the realization of quantum teleportation and quantum memories, or the demonstration of the Einstein-Podolsky-Rosen paradox. These applications rely on techniques to manipulate and detect coherences of quantum fields, the quadratures. Whereas in optics coherent homodyne detection of quadratures is a standard technique, for massive particles a corresponding method was missing. Here we report the realization of an atomic analogue to homodyne detection for the measurement of matter-wave quadratures. The application of this technique to a quantum state produced by spin-changing collisions in a Bose-Einstein condensate reveals continuous-variable entanglement, as well as the twin-atom character of the state. Our results provide a rare example of continuous-variable entanglement of massive particles. The direct detection of atomic quadratures has applications not only in experimental quantum atom optics, but also for the measurement of fields in many-body systems of massive particles.

Decays of the Three Top Contributors to the Reactor ν[over ¯]_{e} High-Energy Spectrum,

We report total absorption spectroscopy measurements of ^{92}Rb, ^{96gs}Y, and ^{142}Cs ß decays, which are the most important contributors to the high energy ν[over ¯]_{e} spectral shape in nuclear reactors. These three ß decays contribute 43% of the ν[over ¯]_{e} flux near 5.5 MeV emitted by nuclear reactors. This ν[over ¯]_{e} energy is particularly interesting due to spectral features recently observed in several experiments including the Daya Bay, Double Chooz, and RENO Collaborations. Measurements were conducted at Oak Ridge National Laboratory by means of proton-induced fission of ^{238}U with on-line mass separation of fission fragments and the Modular Total Absorption Spectrometer. We observe a ß-decay pattern that is similar to recent measurements of ^{92}Rb, with a ground-state to ground-state ß feeding of 91(3)%. We verify the ^{96gs}Y ground-state to ground-state ß feeding of 95.5(20)%. Our measurements substantially modify the ß-decay feedings of ^{142}Cs, reducing the ß feeding to ^{142}Ba states below 2 MeV by 32% when compared with the latest evaluations. Our results increase the discrepancy between the observed and the expected reactor ν[over ¯]_{e} flux between 5 and 7 MeV, the maximum excess increases from ∼10% to ∼12%.

Evidence for Gamow-Teller Decay of

The ß-delayed neutron emission of ^{83,84}Ga isotopes was studied using the neutron time-of-flight technique. The measured neutron energy spectra showed emission from states at excitation energies high above the neutron separation energy and previously not observed in the ß decay of midmass nuclei. The large decay strength deduced from the observed intense neutron emission is a signature of Gamow-Teller transformation. This observation was interpreted as evidence for allowed ß decay to ^{78}Ni core-excited states in ^{83,84}Ge favored by shell effects. We developed shell model calculations in the proton fpg_{9/2} and neutron extended fpg_{9/2}+d_{5/2} valence space using realistic interactions that were used to understand measured ß-decay lifetimes. We conclude that enhanced, concentrated ß-decay strength for neutron-unbound states may be common for very neutron-rich nuclei. This leads to intense ß-delayed high-energy neutron and strong multineutron emission probabilities that in turn affect astrophysical nucleosynthesis models.

Nonlinear atom interferometer surpasses classical precision limit.

Interference is fundamental to wave dynamics and quantum mechanics. The quantum wave properties of particles are exploited in metrology using atom interferometers, allowing for high-precision inertia measurements. Furthermore, the state-of-the-art time standard is based on an interferometric technique known as Ramsey spectroscopy. However, the precision of an interferometer is limited by classical statistics owing to the finite number of atoms used to deduce the quantity of interest. Here we show experimentally that the classical precision limit can be surpassed using nonlinear atom interferometry with a Bose-Einstein condensate. Controlled interactions between the atoms lead to non-classical entangled states within the interferometer; this represents an alternative approach to the use of non-classical input states. Extending quantum interferometry to the regime of large atom number, we find that phase sensitivity is enhanced by 15 per cent relative to that in an ideal classical measurement. Our nonlinear atomic beam splitter follows the 'one-axis-twisting' scheme and implements interaction control using a narrow Feshbach resonance. We perform noise tomography of the quantum state within the interferometer and detect coherent spin squeezing with a squeezing factor of -8.2 dB (refs 11-15). The results provide information on the many-particle quantum state, and imply the entanglement of 170 atoms.

[Characteristics of neuromuscular scoliosis]. / Besonderheiten neuromuskulärer Skoliosen.

Usually, neuromuscular scolioses become clinically symptomatic relatively early and are rapidly progressive even after the end of growth. Without sufficient treatment they lead to a severe reduction of quality of life, to a loss of the ability of walking, standing or sitting as well as to an impairment of the cardiopulmonary system resulting in an increased mortality. Therefore, an intensive interdisciplinary treatment by physio- and ergotherapists, internists, pediatricians, orthotists, and orthopedists is indispensable. In contrast to idiopathic scoliosis the treatment of patients with neuromuscular scoliosis with orthosis is controversially discussed, whereas physiotherapy is established and essential to prevent contractures and to maintain the residual sensorimotor function.Frequently, the surgical treatment of the scoliosis is indicated. It should be noted that only long-segment posterior correction and fusion of the whole deformity leads to a significant improvement of the quality of life as well as to a prevention of a progression of the scoliosis and the development of junctional problems. The surgical intervention is usually performed before the end of growth. A prolonged delay of surgical intervention does not result in an increased height but only in a deformity progression and is therefore not justifiable. In early onset neuromuscular scolioses guided-growth implants are used to guarantee the adequat development. Because of the high complication rates, further optimization of these implant systems with regard to efficiency and safety have to be addressed in future research.

[Cytology of cerebrospinal fluid : Standards, importance and modern methods]. / Liquorzytologie : Standards, Stellenwert und moderne Methoden.

Cytology is an integral part of cerebrospinal fluid (CSF) analysis. It is relevant for the diagnostics and differential diagnosis of inflammatory, hemorrhagic and neoplastic central nervous system (CNS) processes. This article summarizes the recommended procedures and typical clinical patterns. In addition, modern immunocytochemical and flow cytometry methods for CSF cytology are presented. In particular, the diagnostic contribution and clinical relevance in several CNS conditions are discussed.

Emotional well-being of living kidney donors: findings from the RELIVE Study.

Following kidney donation, short-term quality of life outcomes compare favorably to US normative data but long-term effects on mood are not known. In the Renal and Lung Living Donors Evaluation Study (RELIVE), records from donations performed 1963-2005 were reviewed for depression and antidepressant use predonation. Postdonation, in a cross-sectional cohort design 2010-2012, donors completed the Patient Health Questionnaire (PHQ-9) depression screening instrument, the Life Orientation Test-Revised, 36-Item Short Form Health Survey and donation experience questions. Of 6909 eligible donors, 3470 were contacted and 2455 participated (71%). The percent with depressive symptoms (8%; PHQ-9>10) was similar to National Health and Nutrition Examination Survey participants (7%, p=0.30). Predonation psychiatric disorders were more common in unrelated than related donors (p=0.05). Postdonation predictors of depressive symptoms included nonwhite race OR=2.00, p=0.020), younger age at donation (OR=1.33 per 10 years, p=0.002), longer recovery time from donation (OR=1.74, p=0.0009), greater financial burden (OR=1.32, p=0.013) and feeling morally obligated to donate (OR=1.23, p=0.003). While cross-sectional prevalence of depression is comparable to population normative data, some factors identifiable around time of donation, including longer recovery, financial stressors, younger age and moral obligation to donate may identify donors more likely to develop future depression, providing an opportunity for intervention.

Two decades of demography reveals that seed and seedling transitions limit population persistence in a translocated shrub.

BACKGROUND AND AIMS: Olearia flocktoniae is an endangered shrub that was passively translocated from its natural ecosystem, where it has since gone extinct. This study aimed to determine sensitivities vital to populations persisting in human-created areas. METHODS: Population colonization, longevity and extinction were investigated over 20 years using 133 populations. Seed-bank longevity was determined from germination trials of seeds exhumed from extinct and extant sites via a 10-year glasshouse trial and by in situ sowing experiments. From 27 populations, 98 cohorts were followed and matrix models of transitions from seeds to adults were used to evaluate the intrinsic rate of population growth against disturbance histories. Ten populations (38 cohorts) with different disturbance histories were used to evaluate sensitivities in vital rates. KEY RESULTS: Most populations had few individuals (∼30) and were transient (<5 years above ground). The intrinsic population growth rate was rarely >1 and all but two populations were extinct at year 20. Seeds were short-lived in situ. Although >1000 seeds per plant were produced annually in most populations, sensitivity analysis showed that the transition to the seed bank and the transition from the seed bank to seedlings are key vulnerabilities in the life-cycle. CONCLUSIONS: Seedling establishment is promoted by recent disturbance. Increasing the number of disturbance events in populations, even severe disturbances that almost extirpate populations, significantly increases longer-term population persistence. Only populations that were disturbed annually survived the full 20 years of the study. The results show that translocated populations of O. flocktoniae will fail to persist without active management.

Clonal growth is enhanced in the absence of a mating morph: a comparative study of fertile stylar polymorphic and sterile monomorphic populations of Nymphoides montana (Menyanthaceae).

BACKGROUND AND AIMS: Many aquatic species with stylar polymorphisms have the capacity for clonal and sexual reproduction and are sensitive to the balance of the two reproductive modes when there are a limited number of mating morphs within a population. This study asked how the clonal and sexual reproductive modes perform in populations that contain only a single morph and where fitness gain through sexual reproduction is rare. In clonal aquatic Nymphoides montana, polymorphic populations normally contain two mating morphs in equal frequencies. Populations are sexually fertile and appear to be maintained by pollen transfer between the two partners. However, in a monomorphic population of N. montana where mating opportunities are unavailable, female and male function is impaired and clonality maintains the population. Here, the consequences of intraspecific variation in sexuality were explored between monomorphic and polymorphic N. montana populations in eastern Australia. METHODS: Comparative measurements of male and female fertility, total dry mass and genotypic diversity using ISSR markers were made between populations with variable sexuality. KEY RESULTS AND CONCLUSIONS: Very few seeds were produced in the monomorphic population under natural and glasshouse conditions due to dysfunctional pollen and ovules. Stigma-anther separation was minimal in the monomorphic population, which may be a consequence of the relaxed selective pressures that regulate the maintenance of sexual function. However, clonal reproduction was favoured at the expense of sexual reproduction in the monomorphic population; this may facilitate the establishment of sterility throughout the population via resource reallocation or pleiotropic effects. The ISSR results showed that the monomorphic population was one large, single genotype, unlike the multi-genotypic fertile polymorphic populations. Evolutionary loss of sex in a clonal population in which a mating morph is absent was evident; under these conditions clonal growth may assure reproduction and expand the population via spreading stolons.

Pressure dependent OH yields in the reactions of CH3CO and HOCH2CO with O2.

OH-formation in the reactions of CH3CO (R1) and HOCH2CO (R4) with O2 was studied in He, N2 and air (27 to 400 mbar) using OH-detection by laser induced fluorescence (LIF). 248 nm laser photolysis of COCl2 in the presence of CH3CHO or HOCH2CHO was used as source of the acyl radicals CH3CO and HOCH2CO. The LIF-system was calibrated in back-to-back experiments by the 248 nm laser photolysis of H2O2 as OH radical precursor. A straight-forward analytical expression was used to derive OH yields (α) for both reactions. A Stern-Volmer-analysis results in α1b(-1)(N2) = 1 + (9.4 ± 1.7) × 10(-18) cm(3) molecule(-1) × [M], α1b(-1)(He) = 1 + (3.6 ± 0.6) × 10(-18) cm(3) molecule(-1) × [M] and α4b(-1)(N2) = 1 + (1.85 ± 0.38) × 10(-18) cm(3) molecule(-1) × [M]. Our results for CH3CO are compared to the previous (divergent) literature values whilst that for HOCH2CO, for which no previous data were available, provide some insight into the factors controlling the yield of OH in these reactions.

Direct kinetic study of OH and O3 formation in the reaction of CH3C(O)O2 with HO2.

The reaction between HO2 and CH3C(O)O2 has three exothermic product channels, forming OH (R3a), peracetic acid (R3b), and acetic acid plus O3 (R3c). The branching ratios of the OH- and ozone-forming reaction channels were determined using a combination of laser-induced fluorescence (LIF, for time-resolved OH concentration measurement) and transient absorption spectroscopy (TAS, for time-resolved O3 concentration measurement) following pulsed laser generation of HO2 and CH3C(O)O2 from suitable precursors. TAS was also used to determine the initial concentration of the reactant peroxy radicals. The data were evaluated by numerical simulation using kinetic models of the measured concentration profiles; a Monte Carlo approach was used to estimate the uncertainties of the rate constants (k3) and branching ratios (α) thus obtained. The reaction channel forming OH (R3a) was found to be the most important with α3a = 0.61 ± 0.09 and α3c = 0.16 ± 0.08. The overall rate coefficient of the title reaction was found to be k3 = (2.1 ± 0.4) × 10(-11) cm(3) molecule(-1) s(-1) for both HO2 and DO2. Use of DO2 resulted in an increase in α3a to 0.80 ± 0.14. Comparison with former studies shows that OH formation via (R3) has been underestimated significantly to date. Possible reasons for these discrepancies and atmospheric implications are discussed.