Concluding remarks: Faraday Discussion on astrochemistry at high resolution.

Fifty years on from the first detailed chemical kinetic modelling of astronomical sources, I provide some introductory comments on the history of astrochemistry, summarise some personal views on the topics covered in this discussion meeting, and conclude with some thoughts on its future development. I have left out the jokes.

(Sub)stellar companions shape the winds of evolved stars.

Binary interactions dominate the evolution of massive stars, but their role is less clear for low- and intermediate-mass stars. The evolution of a spherical wind from an asymptotic giant branch (AGB) star into a nonspherical planetary nebula (PN) could be due to binary interactions. We observed a sample of AGB stars with the Atacama Large Millimeter/submillimeter Array (ALMA) and found that their winds exhibit distinct nonspherical geometries with morphological similarities to planetary nebulae (PNe). We infer that the same physics shapes both AGB winds and PNe; additionally, the morphology and AGB mass-loss rate are correlated. These characteristics can be explained by binary interaction. We propose an evolutionary scenario for AGB morphologies that is consistent with observed phenomena in AGB stars and PNe.

Complex organic molecules along the accretion flow in isolated and externally irradiated protoplanetary disks.

The birth environment of the Sun will have influenced the physical and chemical structure of the pre-solar nebula, including the attainable chemical complexity reached in the disk, important for prebiotic chemistry. The formation and distribution of complex organic molecules (COMs) in a disk around a T Tauri star is investigated for two scenarios: (i) an isolated disk, and (ii) a disk irradiated externally by a nearby massive star. The chemistry is calculated along the accretion flow from the outer disk inwards using a comprehensive network which includes gas-phase reactions, gas-grain interactions, and thermal grain-surface chemistry. Two simulations are performed, one beginning with complex ices and one with simple ices only. For the isolated disk, COMs are transported without major chemical alteration into the inner disk where they thermally desorb into the gas reaching an abundance representative of the initial assumed ice abundance. For simple ices, COMs can efficiently form on grain surfaces under the conditions in the outer disk. Gas-phase COMs are released into the molecular layer via photodesorption. For the irradiated disk, complex ices are also transported inwards; however, they undergo thermal processing caused by the warmer conditions in the irradiated disk which tends to reduce their abundance along the accretion flow. For simple ices, grain-surface chemistry cannot efficiently synthesise COMs in the outer disk because the necessary grain-surface radicals, which tend to be particularly volatile, are not sufficiently abundant on the grain surfaces. Gas-phase COMs are formed in the inner region of the irradiated disk via gas-phase chemistry induced by the desorption of strongly bound molecules such as methanol; hence, the abundances are not representative of the initial molecular abundances injected into the outer disk. These results suggest that the composition of comets formed in isolated disks may differ from those formed in externally irradiated disks with the latter composed of more simple ices.

Irradiation of water ice by C(+) ions in the cosmic environment.

We present a first-principles MD (FPMD) study of the interaction of low-energy, positively charged carbon (C(+)) projectiles with amorphous solid water clusters at 30 K. Reactions involving the carbon ion at an initial energy of 11 and 1.7 eV with a 30-molecule cluster have been investigated. Simulations indicate that the neutral isoformyl radical, COH(•), and carbon monoxide, CO, are the dominant products of these reactions. All of these reactions are accompanied by the transfer of a proton from the reacting water molecule to the ice, where it forms a hydronium ion. We find that COH(•) is formed either via a direct, "knock-out", mechanism following the impact of the C(+) projectile upon a water molecule or by creation of a COH2(+) intermediate. The direct mechanism is more prominent at higher energies. CO is generally produced following the dissociation of COH(•). More frequent production of the formyl radical, HCO(•), is observed here than in gas-phase calculations. A less commonly occurring product is the dihydroxymethyl, CH(OH)2(•), radical. Although a minor result, its existence gives an indication of the increasing chemical complexity that is possible in such heterogeneous environments.

Organic synthesis in the interstellar medium by low-energy carbon irradiation.

We present a first principles molecular dynamics (FPMD) study of the interaction of low-energy neutral carbon projectiles with amorphous solid water clusters at 30 K. Reactions involving the carbon atom at an initial energy of 11 and 1.7 eV with 30-molecule clusters have been investigated. Simulations indicate that the formation of hydroxymethylene, an intermediate in formaldehyde production, dominates at the higher energy. The reaction proceeds by fragmenting a water molecule, binding the carbon to the OH radical, and saturating the C valence with a hydrogen atom that can arise from the originally dissociated water molecule, or through a chain of proton transfer events. We identified several possible pathways for the formation of HCOH. When the initial collision occurs at the periphery of the cluster, we observe the formation of CO and the evaporation of water molecules. At the lower energy water fragmentation is not favorable, thus leading to the formation of weakly bound carbon-water complexes.

Furosemide in the treatment of phosgene induced acute lung injury.

METHOD: Using previously validated methods, 16 anaesthetised large white pigs were exposed to phosgene (target inhaled dose 0.3 mg kg(-1)), established on mechanical ventilation and randomised to treatment with either nebulised furosemide (4 ml of 10 mg x ml(-1) solution) or saline control. Treatments were given at 1, 3, 5, 7, 9, 12, 16 and 20 hours post phosgene exposure; the animals were monitored to 24 hours following phosgene exposure. RESULTS: Furosemide treatment had no effect on survival, and had a deleterious effect on PaO2: FiO2 ratio between 19 and 24 hours. All other measures investigated were unaffected by treatment. CONCLUSION: Nebulised furosemide treatment following phosgene induced acute lung injury does not improve survival and worsens PaO2: FiO2 ratio. Nebulised furosemide should be avoided following phosgene exposure.

Blockade of K(ATP) channels reduces endothelial hyperpolarization and leukocyte recruitment upon reperfusion after hypoxia.

Ischemia/reperfusion injury in renal transplantation leads to slow or initial nonfunction, and predisposes to acute and chronic rejection. In fact, severe ischemia reperfusion injury can significantly reduce graft survival, even with modern immunosuppressive agents. One of the mechanisms by which ischemia/reperfusion causes injury is activation of endothelial cells resulting in inflammation. Although several therapies can be used to prevent leukocyte recruitment to ischemic vessels (e.g. antiadhesion molecule antibodies), there have been no clinical treatments reported that can prevent initial immediate neutrophil recruitment upon reperfusion. Using intravital microscopy, we describe abrogation of immediate neutrophil recruitment to ischemic microvessels by the K(ATP) antagonist glibenclamide (Glyburide). Further, we show that glibenclamide can reduce leukocyte recruitment in vitro under physiologic flow conditions. ATP-regulated potassium channels (K(ATP)) are important in the control of cell membrane polarization. Here we describe profound hyperpolarization of endothelial cells during hypoxia, and the reduction of this hyperpolarization using glibenclamide. These findings suggest that control of endothelial membrane potential during ischemia may be an important therapeutic tool in avoiding ischemia/reperfusion injury, and therefore, enhancing transplant long-term function.

Glossary of terms relating to capture-recapture methods.

This glossary provides basic definitions for terms that have a specific meaning in the application of the capture-recapture methodology, particularly with respect to standard techniques for the application of log linear models to multiple lists. In epidemiology, capture-recapture is used for prevalence estimation. It is intended that, as well as being a central point of reference for terms used in the capture-recapture methodology, this glossary should provide a resource for those new to this methodology. It aims to provide a simple introduction using terms that should be understood by an uninitiated audience.

Tissue and organ donation for research in forensic pathology: the MRC Sudden Death Brain and Tissue Bank.

Novel methodological approaches to the investigation of brain and non-central nervous system disorders have led to increased demand for well-characterized, high quality human tissue samples, particularly from control cases. In the setting of the new Human Tissue legislation, we sought to determine whether relatives who have been suddenly bereaved are willing to grant authorization for research use of post mortem tissue samples and organs in sufficient numbers to support the establishment of a brain and tissue bank based in the forensic service. Research authorization was sought from families on the day prior to forensic post mortem examination followed up by written confirmation. We have to date selected individuals who have died suddenly (age range 1-89 years) and who were likely to have normal brains or who had displayed symptoms of a CNS disorder of interest to researchers, including psychiatric disorders. One hundred and eleven families have been approached during the first 2 years of this project. Research use of tissue samples was authorized by 96% of families and 17% agreed to whole brain donation. Audit of families' experience does not suggest that they are further distressed by being approached. Respondents expressed a clear view that the opportunity for research donation should be open to all bereaved families. Despite the sometimes long post mortem intervals, the quality of tissue samples is good, as assessed by a range of markers including Agilent BioAnalyzer quantification of RNA integrity (mean value 6.4). We conclude that the vast majority of families are willing to support research use of post mortem tissues even in the context of sudden bereavement and despite previous adverse publicity. The potential for acquisition of normal CNS and non-CNS tissues and of various hard-to-get CNS disorders suggests that efforts to access the forensic post mortem service for research material are eminently worthwhile.

'The BloodStopper' - experiences with a novel portable hand-held orthopaedic limb tourniquet.

Tourniquets are widely employed in orthopaedic practice to maintain a bloodless operative field during extremity surgery. In areas of the world where reliable pressurized air systems for tourniquet inflation are not available, and as an alternative to the traditional Esmarch bandage, we report on the successful and safe use of a novel hand-held, battery-operated limb tourniquet.

Orthopaedic trauma workload in the former homeland of the Transkei, South Africa.

The Bedford Orthopaedic Centre is situated in Umtata at the heart of the former homeland of the Transkei in the Eastern Cape of South Africa. It acts as an orthopaedic and trauma referral hospital for a mainly rural population approaching 4 million. This article focuses on the workload of the hospital over a 4-month period and like many hospitals in South Africa we highlight the difficulties it faces with the trauma epidemic.

Dissociative recombination of protonated methanol.

The branching ratios of the different reaction pathways and the overall rate coefficients of the dissociative recombination reactions of CH3OH2+ and CD3OD2+ have been measured at the CRYRING storage ring located in Stockholm, Sweden. Analysis of the data yielded the result that formation of methanol or deuterated methanol accounted for only 3 and 6% of the total rate in CH3OH2+ and CD3OD2+, respectively. Dissociative recombination of both isotopomeres mainly involves fragmentation of the C-O bond, the major process being the three-body break-up forming CH3, OH and H (CD3, OD and D). The overall cross sections are best fitted by sigma = 1.2 +/- 0.1 x 10(-15) E(-1.15 +/- 0.02) cm2 and sigma = 9.6 +/- 0.9 x 10(-16) E(-1.20 +/- 0.02) cm2 for CH3OH2+ and CD3OD2+, respectively. From these values thermal reaction rate coefficients of k(T) = 8.9 +/- 0.9 x 10(-7) (T/300)(-0.59 +/- 0.02) cm3 s(-1) (CH3OH2+) and k(T) = 9.1 +/- 0.9 x 10(-7) (T/300)(-0.63 +/- 0.02) cm3 s(-1) (CD3OD2+) can be calculated. A non-negligible formation of interstellar methanol by the previously proposed mechanism via radiative association of CH3+ and H2O and subsequent dissociative recombination of the resulting CH3OH2+ ion to yield methanol and hydrogen atoms is therefore very unlikely.

Deuterated H3+ as a probe of isotope fractionation in star-forming regions.

Observations of molecular D/H ratios in the interstellar medium are used to probe the physical conditions, such as temperature, ionization fraction and the importance of gas-grain reactions. In cold, dense regions, such as cores which are collapsing to form stars, the level of deuterium fractionation depends on the conversion of H3+ into its deuterated isotopologues (H2D+, D2H+ and D3+). The relative abundances of these molecules uniquely probe the centres of these cores where other, heavier, species have frozen onto dust grains. We present models of the deuterium chemistry close to the centre of a pre-stellar core, in the last stage before the star forms, showing the dependence of the observable molecular D/H ratios on the physical parameters and rate coefficients that are assumed. We compare model predictions with the latest observations of these regions.

Elucidar la contribución de las proteínas en las lágrimas. Un reto para los investigadores / Elucidate the contribution of proteins to tears. A challenge for researchers

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Insertion of tear proteins into a meibomian lipids film.

The eyelid meibomian gland secretions form the outer layer of the tear film. That layer functions as a lubricant during a blink, and as a barrier against intrusion of foreign bodies. The lipid film is also exposed to proteins present in the aqueous phase that may adsorb there, and thus form an integral part of the surface of the tear film, or possibly, cause disruption to the outermost layer. Therefore, the adsorption of tear proteins to the meibomian lipid layer was object of the present investigation. A model tear was set up coating a pendant drop of saline with a film of meibomian lipids and measuring variations of the interfacial pressure after the injection of tear proteins into the aqueous subphase at their physiological concentration. All tear proteins adsorbed at the interface causing the initial surface pressure to increase. For each protein, a limiting surface pressure at which a given protein was no longer able to insert into the lipid layer was found. Among the proteins tested, lipocalin was the most surface active one and inserted into the lipid layer in the whole range of surface pressure exerted by the meibomian lipid mixture. Lactoferrin, lysozyme and IgA also interacted with the lipids whereas albumin interacted more weakly. The timescale of the protein insertion into the lipid layer was of the order of 10(2) s. It was hypothesized that protein adsorption at the interface could be associated with structural changes. Indeed, the enzymatic activity of lysozyme was maintained in the presence of an outermost meibomian lipid layer that prevented its denaturation while exposure at the air/aqueous interface induced significant lysozime degradation. meibomian lipid composition is therefore functional to maintain tear proteins activity.

Transient and steady state focal and pattern electroretinogram nerve section losses in cats with unilateral optic.

This study shows the ketamine/xylazine anaesthetised cat is a useful model for the effect of unilateral optic nerve section on pattern electroretinograms (PERGs), especially if stimuli extending to previously untested low spatial frequencies and preferably down to the focal ERG (FERG) are included. The transient reversal rate, seldom used in animals,has advantages over steady state recording. Transient PERGs had signs of true spatial tuning, a higher amplitude and signal noise ratio and showed the effect of optic atrophy at low spatial frequencies more rapidly.

The dynamics of heroin use; implications for intervention.

STUDY OBJECTIVE: To use a readily available dataset to detect periods of epidemic change and to examine the progression of heroin epidemics in different geographical areas. To consider the implications of epidemic change for strategies to tackle drug misuse. DESIGN: Comparison of trends in new treatment demand, observed incidence, and age specific population rates for treated heroin users in two geographical areas. PARTICIPANTS: Heroin users recorded to have sought treatment. MAIN RESULTS: The areas studied seem to show differences with respect to trends in new treatment demand, incidence of heroin use and distribution of age specific population rates; indicating that they may be at different epidemic stages. CONCLUSIONS: These analyses show how areas may differ with respect to epidemic progression of heroin use. It is essential that government strategies, and local responses to these, should be cognisant of these dynamics.