Chemical modelling of dust–gas chemistry within AGB outflows – II. Effect of the dust-grain size distribution

Asymptotic giant branch (AGB) stars are, together with supernovae, the main contributors of stellar dust to the interstellar medium (ISM). Dust grains formed by AGB stars are thought to be large. However, as dust nucleation and growth within their outflows are still not understood, the dust-grain size distribution (GSD) is unknown. This is an important uncertainty regarding our knowledge of the chemical and physical history of interstellar dust, as AGB dust forms ∼70 per cent∼70 per cent of the starting point of its evolution. We expand on our chemical kinetics model, which uniquely includes a comprehensive dust–gas chemistry. The GSD is now allowed to deviate from the commonly assumed canonical Mathis, Rumpl & Nordsieck distribution. We find that the specific GSD can significantly influence the dust–gas chemistry within the outflow. Our results show that the level of depletion of gas-phase species depends on the average grain surface area of the GSD. Gas-phase abundance profiles and their possible depletions can be retrieved from observations of molecular emission lines when using a range of transitions. Because of degeneracies within the prescription of GSD, specific parameters cannot be retrieved, only (a lower limit to) the average grain surface area. None the less, this can discriminate between dust composed of predominantly large or small grains. We show that when combined with other observables such as the spectral energy distribution and polarized light, depletion levels from molecular gas-phase abundance profiles can constrain the elusive GSD of the dust delivered to the ISM by AGB outflows

Convergence of Discretized Light Cone Quantization in the small mass limit

I discuss the slow convergence of Discretized Light Cone Quantization (DLCQ) in the small mass limit and suggest a solution.Comment: 8 pages, 5 Postscript figures, uses boxedeps.te

Chemical modelling of dust-gas chemistry within AGB outflows III. Photoprocessing of the ice and return to the ISM

To explain the properties of dust in the interstellar medium (ISM), the presence of a refractory organic mantle is necessary. The outflows of AGB stars are among the main contributors of stellar dust to the ISM. We present the first study of the refractory organic contribution of AGB stars to the ISM. Based on laboratory experiments, we included a new reaction in our extended chemical kinetics model: the photoprocessing of volatile complex ices into inert refractory organic material. The refractory organic feedback of AGB outflows to the ISM is estimated using observationally motivated parent species and grids of models of C-rich and O-rich outflows. Refractory organic material is mainly inherited from the gas phase through accretion onto the dust and subsequent photoprocessing. Grain-surface chemistry, initiated by photodissociation of ices, produces only a minor part and takes place in a sub-monolayer regime in almost all outflows. The formation of refractory organic material increases with outflow density and depends on the initial gas-phase composition. While O-rich dust is negligibly covered by refractory organics, C-rich dust has an average coverage of 3−9%3−9%⁠, but can be as high as 8−22%8−22%⁠. Although C-rich dust does not enter the ISM bare, its average coverage is too low to influence its evolution in the ISM or significantly contribute to the coverage of interstellar dust. This study opens up questions on the coverage of other dust-producing environments. It highlights the need for an improved understanding of dust formation and for models specific to density structures within the outflow

A cross-sectional study of psychological complaints and quality of life in severely injured patients

Purpose: The purpose of this study was to examine the incidence of psychological complaints and the relationship of these complaints with the quality of life (QOL) and accident- and patient-related factors among severely injured patients after the rehabilitation phase. Methods: Patients of 18 years or older with an injury severity score above 15 were included 15-53 months after their accident. Accident and patient characteristics were obtained from questionnaires and the trauma registry. Several questionnaires (Hospital Anxiety and Depression Scale, Impact of Events Scale, and Cognitive Failure Questionnaire) were used to determine the symptoms of psychological problems (anxiety or depression, post-traumatic stress disorder, or subjective cognitive complaints, respectively). The World Health Organization Quality of Life-Bref was used to determine QOL. A reference group of the Dutch general population was used for comparison of QOL scores. Results: The participation rate was 62 % (n = 173). At the time of the study, 30.1 % (n = 52) of the investigated patients had psychological complaints. No relation between psychological complaints and somatic severity or type of injury was found. Patients who were employed before the accident or resumed working reported less psychological complaints. Use of any medication before the accident and treatment for pre-accidental psychological problems were positively related to psychological complaints afterwards. QOL of severely injured patients was impaired in comparison with the general Dutch population, but only for those with psychological complaints. Conclusions: Psychological complaints seem to be an important and underestimated factor for a decreased QOL among severely injured patients

Chemical modelling of dust–gas chemistry within AGB outflows – I. Effect on the gas-phase chemistry

Chemical modelling of asymptotic giant branch (AGB) outflows is typically focused on either non-thermodynamic equilibrium chemistry in the inner region or photon-driven chemistry in the outer region. We include, for the first time, a comprehensive dust–gas chemistry in our AGB outflow chemical kinetics model, including both dust–gas interactions and grain-surface chemistry. The dust is assumed to have formed in the inner region, and follows an interstellar-like dust-size distribution. Using radiative transfer modelling, we obtain dust temperature profiles for different dust types in an O-rich and a C-rich outflow. We calculate a grid of models, sampling different outflow densities, drift velocities between the dust and gas, and dust types. Dust–gas chemistry can significantly affect the gas-phase composition, depleting parent and daughter species and increasing the abundance of certain daughter species via grain-surface formation followed by desorption/sputtering. Its influence depends on four factors: outflow density, dust temperature, initial composition, and drift velocity. The largest effects are for higher density outflows with cold dust and O-rich parent species, as these species generally have a larger binding energy. At drift velocities larger than ∼10 km s−1, ice mantles undergo sputtering; however, they are not fully destroyed. Models with dust–gas chemistry can better reproduce the observed depletion of species in O-rich outflows. When including colder dust in the C-rich outflows and adjusting the binding energy of CS, the depletion in C-rich outflows is also better reproduced. To best interpret high-resolution molecular line observations from AGB outflows, dust–gas interactions are needed in chemical kinetics models

Glueball calculations in large-N_c gauge theory

We use the light-front Hamiltonian of transverse lattice gauge theory to compute from first principles the glueball spectrum and light-front wavefunctions in the leading order of the 1/N_c colour expansion. We find 0^{++}, 2^{++}, and 1^{+-} glueballs having masses consistent with N_c=3 data available from Euclidean lattice path integral methods. The wavefunctions exhibit a light-front constituent gluon structure.Comment: 4 pages, 2 figures, uses macro boxedeps.tex, minor corrections in revised versio

Quality of life in severely injured patients depends on psychosocial factors rather than on severity or type of injury

Background: Former studies have demonstrated that health-related quality of life is decreased in severely injured patients. However, in those studies patients were asked about their functioning and not about their (dis)contentment concerning their functioning. Little is known about how severely injured patients experience their quality of life (QOL). The objective of this cross-sectional study was to measure this subjective QOL of severely injured patients after their rehabilitation phase and to examine which accident- and patient-related factors affect the QOL of these patients. Methods: Patients of 18 years or older with an injury severity score (ISS) above 15 were included 15-53 months after their accident. Comorbidity before the accident, accident and sociodemographic characteristics, and QOL were obtained from the trauma registry and questionnaires. The WHOQOL-BREF was used to measure QOL. A reference group of the Dutch general population was used for comparison. Results: The participation rate was 61% (n = 173). Compared with the reference data, severely injured patients experienced a significantly worse QOL in all domains except social relations. The QOL scores were significantly decreased in all domains for patients with intracranial injury in combination with other injuries. Patients with a severe intracranial injury (AIS > 3) only reported significantly impaired QOL in the general and physical domains. Patients who resumed working or lived with others had significantly higher scores in all domains of QOL than patients who did not work anymore or were living alone. Significantly lower QOL scores were obtained from patients with comorbidity before the accident and from patients with longer durations of intensive care unit (ICU) treatment or hospitalisation. Gender, accident characteristics and time since the accident did not appear to be important for experienced QOL. Conclusions: The experience of impaired QOL appears to depend on living alone, inability to return to work and pre-accidental comorbidity rather than on the injured body area or the severity of the injury. Duration of hospital or ICU stay is important to subsequent QOL, even if ISS or body region is not

The efficacy of topical imiquimod in high-grade cervical intraepithelial neoplasia:A systematic review and meta-analysis

Objective: A major side effect of cervical excision for high-grade cervical intraepithelial neoplasia (CIN) is premature birth. A non-invasive treatment for reproductive age women is warranted. The aim of the present study was to determine the efficacy of topical imiquimod in the treatment of high-grade CIN, defined as a regression to ≤CIN 1, and to determine the clearance rate of high-risk human papillomavirus (hr-HPV), compared with surgical treatment and placebo. Methods: Databases were searched for articles from their inception to February 2023.The study protocol number was INPLASY2022110046. Original studies reporting the efficacy of topical imiquimod in CIN 2, CIN 3 or persistent hr-HPV infections were included. The study followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses checklist. Results: Five studies were included (n = 463). Histological regression to ≤CIN 1 was 55% in imiquimod versus 29% in placebo, and 93% in surgical treatment. Imiquimod-treated women had a greater odds of histological regression to ≤CIN 1 than placebo (odds ratio [OR] 4.17, 95% confidence interval [CI] 2.03–8.54). In comparison to imiquimod, surgical treatment had an OR of 14.81(95% CI 6.59–33.27) for histological regression to ≤CIN 1. The hr-HPV clearance rate was 53.4% after imiquimod and 66% after surgical treatment (95% CI 0.62–23.77). Conclusions: The histological regression rate is highest for surgical treatment followed by imiquimod treatment and placebo.</p

Encouraging survival rates in patients with acute myocardial infarction treated with an intra-aortic balloon pump

Objective To evaluate a 30-day and long-term outcome of patients with acute myocardial infarction (AMI) treated with intra-aortic balloon pump (IABP) counterpulsation and to identify predictors of a 30-day and long-term all-cause mortality. Methods Retrospective cohort study of 437 consecutive AMI patients treated with IABP between January 1990 and June 2004. A Cox proportional hazards model was used to identify predictors of a 30-day and long-term all-cause mortality. Results Mean age of the study population was 61±11 years, 80% of the patients were male, and 68% had cardiogenic shock. Survival until IABP removal after successful haemodynamic stabilisation was 78% (n=341). Cumulative 30-day survival was 68%. Median follow-up was 2.9 years (range, 6 months to 15 years). In patients who survived until IABP removal, cumulative 1-, 5-, and 10-year survival was 75%