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We present the spectra of 5 OH/IR stars observed with the Short Wavelength Spectrometer (SWS) on board the Infrared Space Observatory (ISO). The spectra are dominated by dust features, both in the amorphous and crystalline state and illustrate the influence of the mass loss rate on the observed spectral features. [ABSTRACT FROM AUTHOR]

Context. The diffuse interstellar bands (DIBs) are a set of hundreds of unidentified absorption features that appear almost ubiquitously throughout the interstellar medium. Most DIBs appear at optical wavelengths, but some are in the near-infrared. Aims. We aim to characterise near-infrared DIBs at high spectral resolving power towards multiple targets. Methods. We observed 76 early-type stars at a resolving power of 50 000 (velocity resolution 6 km s1) and signal-to-noise ratios of several hundreds using the CRyogenic high-resolution InfraRed Echelle Spectrograph (CRIRES). These data allow us to investigate the DIBs around 1318.1, 1527.4, 1561.1, 1565.1, 1567.0, 1574.4, and 1624.2 nm. We detected a total of six DIB features and 17 likely stellar features through comparisons with a model spectrum computed with CMFGEN. Additionally, we measured equivalent widths of the DIBs at 1318.1 and 1527.4 nm using observations with X-shooter towards ten very highly reddened (3:2 < E(BV) < 6:5) Cepheid variable stars and towards four stars observed at low values of precipitable water vapour as well as by using other archive data. Results. We measured correlations (correlation coefficient r 0:73-0.96, depending on the subsample used) between DIB equivalent width and reddening for the DIBs at 1318.1, 1561.1, 1565.1, and 1567.0 nm. Comparing the near-infrared DIBs with 50 of the strongest optical DIBs, we find correlations r > 0:8 between the 1318, 1527, 1561, 1565, and 1567 nm and the optical DIBs 5705, 5780, 6203, 6283, and 6269 Å. The 5797 Å DIB is less well correlated with the near-infrared DIBs. The DIB at 9632.1 Å, which is likely C+ 60, is not well correlated with the 1318.1 nm DIB. Partial correlation coefficients using E(B-V) as the covariate were also determined. For stars earlier than B2, the 1318.1 nm DIB is affected by an emission line on its blue wing that is likely stellar in nature, although we cannot rule out an interstellar or circumstellar origin for this line caused by, for example, a DIB in emission. The 1318.1 nm DIB also has an extended red wing. The line is reasonably well fitted by two Gaussian components, although neither the component equivalent width (EW) ratios nor the separation between components are obviously correlated with such indicators as --5780/5797 and reddening. The EW at 1318 nm correlates with H I with EW(1318 nm)/E(B V) decreasing with f (H2). Five pairs of stars within one arcmin of each other show very similar 1318.1 nm DIB profiles. Possible variation in the 1318.1 nm feature is seen between HD145501 and HD145502 (separated by 41 arcsec, equivalent to 7200 au) and HD168607 and HD168625 (separated by 67 arcsec, equivalent to 0.52 pc on the plane of the sky). Seventeen sightlines have repeat CRIRES observations separated by six to 14 months, and two sightlines have repeat X-shooter observations separated by 9.9 yr. No time variability was detected in the 1318.1 nm DIB in the CRIRES data nor in the 5780.5 Å, 5797.1 Å, 1318.1 nm, and 1527.4 nm DIBs. Tentative time variation is observed in the C+ 60 DIBs at 9577 and 9632 Å towards HD183143, although it is very close to the noise level and requires confirmation. Conclusions. The Near Infrared (NIR) DIBs observed occur more in more UV-irradiated regions than the 5797 Å DIB allowing the study of heavily reddened sightlines. Future searches for time variability in DIBs will require either higher quality data, larger intervals between epochs, or both. [ABSTRACT FROM AUTHOR]

Our understanding on the role of amorphous carbon in the interstellar medium to form complex structures, such as carbon nanotube/graphene/fullerene, is limited to date. We have investigated how shocks may induce physico-chemical transformation in amorphous carbon by subjecting samples of carbon nanopowder to high-temperature shocks, ∼7300 K, in a hydrogen-free environment for about 2 ms using a shock tube. The shock conditions achieved in the laboratory mimics low velocity interstellar shocks. Post shock samples were analyzed using Raman Spectroscopy and High Resolution – Transmission Electron Microscopy. We have found compelling evidence for the formation of carbon nanotube, graphene, and various other carbon nanostructures induced by the shock. Our results show that shocks in the interstellar medium can provide important chemical pathways to the formation of fullerenes and suggests that other carbonaceous structures may be present as well. [ABSTRACT FROM AUTHOR]

The Nearby Evolved Stars Survey (NESS) is a volume-complete sample of ∼850 Galactic evolved stars within 3 kpc at (sub-)mm wavelengths, observed in the CO J  = (2–1) and (3–2) rotational lines, and the sub-mm continuum, using the James Clark Maxwell Telescope and Atacama Pathfinder Experiment. NESS consists of five tiers, based on distances and dust-production rate (DPR). We define a new metric for estimating the distances to evolved stars and compare its results to Gaia EDR3. Replicating other studies, the most-evolved, highly enshrouded objects in the Galactic Plane dominate the dust returned by our sources, and we initially estimate a total DPR of 4.7 × 10−5 M⊙ yr−1 from our sample. Our sub-mm fluxes are systematically higher and spectral indices are typically shallower than dust models typically predict. The 450/850 |$\mu$| m spectral indices are consistent with the blackbody Rayleigh–Jeans regime, suggesting a large fraction of evolved stars have unexpectedly large envelopes of cold dust. [ABSTRACT FROM AUTHOR]

We report new spectroscopic observations of the magnetic Of?p star HD 148937 obtained since 2015 that differ qualitatively from its extensive historical record of weak, periodic spectral variations. This remarkable behaviour represents clear evidence for an unprecedented change in the character of variability of the star. In this paper, we describe the new spectral properties and compare them to the previous line profiles. Based on measurements of the radial velocities of the C  iii /N  iii emission lines near 4640 Å and the C  iv absorption lines near 5800 Å, we infer that HD 148937 is likely a high-mass, double-lined spectroscopic binary. Combining the spectroscopic orbit with an archival interferometric measurement of the apparent separation of the equal brightness components, we tentatively conclude that HD 148937 consists of two O-type stars with masses of approximately 34 and 49 M⊙, orbiting in an eccentric (e  = 0.75), long-period (P orb ∼ 26 yr) orbit. We discuss the potential relationship of the binary system to the peculiar properties of HD 148937, and propose future observations to refine the orbital and stellar properties. [ABSTRACT FROM AUTHOR]

Emission bands from polycyclic aromatic hydrocarbons (PAHs) dominate the mid-infrared spectra of a wide variety of astronomical sources, encompassing nearly all stages of stellar evolution. Despite their similarities, details in band positions and shapes have allowed a classification of PAH emission to be developed. It has been suggested that this classification is in turn associated with the degree of photoprocessing of PAHs. Over the past decade, a more complete picture of the PAH interstellar life-cycle has emerged, in which a wide range of PAH species are formed during the later stages of stellar evolution. After this they are photoprocessed, increasing the relative abundance of the more stable (typically larger and compact) PAHs. For this work we have tested the effect of the symmetry, size, and structure of PAHs on their fragmentation pattern and infrared spectra by combining experiments at the free electron laser for infrared experiments (FELIX) and quantum chemical computations. Applying this approach to the cations of four molecular species, perylene (C20H12), peropyrene (C26H14), ovalene (C32H14) and isoviolanthrene (C34H18), we find that a reduction of molecular symmetry causes the activation of vibrational modes in the 7–9 μm range. We show that the IR characteristics of less symmetric PAHs can help explain the broad band observed in the class D spectra, which are typically associated with a low degree of photoprocessing. Such large, nonsymmetrical irregular PAHs are currently largely missing from the NASA Ames PAH database. The band positions and shapes of the largest more symmetric PAH measured here, show the best resemblance with class A and B sources, representative of regions with high radiation fields and thus heavier photoprocessing. Furthermore, the dissociation patterns observed in the mass spectra hint to an enhanced stability of the carbon skeleton in more symmetric PAHs with respect to the irregular and less symmetric species, which tend to loose carbon containing units. Although not a direct proof, these findings are fully in line with the grandPAH hypothesis, which claims that symmetric large PAHs can survive as the radiation field increases, while their less symmetric counterparts are destroyed or converted to symmetric PAHs. [ABSTRACT FROM AUTHOR]

We present infrared (IR) and submillimetre observations of the Crab-like supernova remnant (SNR) G54.1+0.3 including 350 $$\mu$$ m (SHARC-II), 870 $$\mu$$ m (LABOCA), 70, 100, 160, 250, 350, and 500  $$\mu$$ m (Herschel), and 3–40  $$\mu$$ m (Spitzer). We detect dust features at 9, 11, and 21  $$\mu$$ m and a long-wavelength continuum dust component. The 21  $$\mu$$ m dust coincides with [Ar  ii ] ejecta emission, and the feature is remarkably similar to that in Cas A. The IRAC 8 $$\mu$$ m image including Ar ejecta is distributed in a shell-like morphology which is coincident with dust features, suggesting that dust has formed in the ejecta. We create a cold dust map that shows excess emission in the northwestern shell. We fit the spectral energy distribution of the SNR using the continuous distributions of ellipsoidal grain model of pre-solar grain SiO2 that reproduces the 21 and 9  $$\mu$$ m dust features and discuss grains of silicon carbide and polycyclic aromatic hydrocarbon that may be responsible for the 10–13  $$\mu$$ m dust features. To reproduce the long-wavelength continuum, we explore models consisting of different grains including Mg2SiO4, MgSiO3, Al2O3, FeS, carbon, and Fe3O4. We tested a model with a temperature-dependent silicate absorption coefficient. We detect cold dust (27–44 K) in the remnant, making this the fourth such SNR with freshly formed dust. The total dust mass in the SNR ranges from $$0.08\text{ to }0.9\, {\rm M}_{\odot }$$ depending on the grain composition, which is comparable to predicted masses from theoretical models. Our estimated dust masses are consistent with the idea that SNe are a significant source of dust in the early Universe. [ABSTRACT FROM AUTHOR]

It is well known that the dust properties of the di use interstellar medium exhibit variations towards di erent sight-lines on a large scale.We have investigated the variability of the dust characteristics on a small scale and from cloud-to-cloud.We use low-resolution spectro-polarimetric data obtained in the context of the Large Interstellar Polarisation Survey (LIPS) towards 59 sight-lines in the Southern Hemisphere and we fit these data using a dust model composed of silicate and carbon particles with sizes from the molecular to the sub-micrometre domain. Large (⩾6 nm) silicates of prolate shape account for the observed polarisation. For 32 sight-lines we complement our data set with UVES archive high-resolution spectra, which enable us to establish the presence of single-cloud or multiple-clouds towards individual sight-lines. We find that the majority of these 35 sight-lines intersect two or more clouds, while eight of them are dominated by a single absorbing cloud. We confirm several correlations between extinction and parameters of the Serkowski law with dust parameters, but we also find previously undetected correlations between these parameters that are valid only in single-cloud sight-lines. We find that interstellar polarisation from multiple-clouds is smaller than from single-cloud sightlines, showing that the presence of a second or more clouds depolarises the incoming radiation. We find large variations of the dust characteristics from cloud-to-cloud. However, when we average a suffciently large number of clouds in single-cloud or multiple-cloud sight-lines, we always retrieve similar mean dust parameters. The typical dust abundances of the single-cloud cases are [C]/[H] = 92 ppm and [Si]/[H] = 20 ppm. [ABSTRACT FROM AUTHOR]

Context. Photodissociation regions (PDRs) contain a large portion of all of the interstellar matter in galaxies. Classical examples include the boundaries between ionized regions and molecular clouds in regions of massive star-formation, marking the point where all of the photons that are energetic enough to ionize hydrogen have been absorbed. Aims. To determine the physical properties of the PDRs associated with the star-forming regions IRAS 23133+6050 and S 106 and present them in the context of other Galactic PDRs associated with massive star-forming regions. Methods. We employ Herschel PACS and SPIRE spectroscopic observations to construct a full 55-650 μm spectrum of each object from which we measure the PDR cooling lines, other fine- structure lines, CO lines, and the total far-infrared flux. These measurements (and combinations thereof) are then compared to standard PDR models. Subsequently, detailed numerical PDR models are compared to these predictions, yielding additional insight into the dominant thermal processes in the PDRs and their structures. Results. We find that the PDRs of each object are very similar and can be characterized by a two-phase PDR model with a very dense, highly UV irradiated phase (n ∼ 106 cm-3, G0 ∼ 105) interspersed within a lower density, weaker radiation field phase (n ∼ 104 cm-3, G0 ∼ 104). We employed two different numerical models to investigate the data. We first used RADEX models to fit the peak of the 12CO ladder, which in conjunction with the properties derived, yielded a temperature of around 300 K. Subsequent numerical modeling with a full PDR model revealed that the dense phase has a filling factor of around 0.6 in both objects. The shape of the 12CO ladder was consistent with these components, with heating dominated by grain photoelectric heating. An extra excitation component for the heightest-J lines (J > 20) is required for S 106. [ABSTRACT FROM AUTHOR]

Most low-mass stars form in stellar clusters that also contain massive stars, which are sources of far-ultraviolet (FUV) radiation. Theoretical models predict that this FUV radiation produces photodissociation regions (PDRs) on the surfaces of protoplanetary disks around low-mass stars, which affects planet formation within the disks. We report James Webb Space Telescope and Atacama Large Millimeter Array observations of a FUV-irradiated protoplanetary disk in the Orion Nebula. Emission lines are detected from the PDR; modeling their kinematics and excitation allowed us to constrain the physical conditions within the gas. We quantified the mass-loss rate induced by the FUV irradiation and found that it is sufficient to remove gas from the disk in less than a million years. This is rapid enough to affect giant planet formation in the disk.

Forty years ago, it was proposed that gas-phase organic chemistry in the interstellar medium can be initiated by the methyl cation CH 3 + (refs. 1-3 ), but so far it has not been observed outside the Solar System 4,5 . Alternative routes involving processes on grain surfaces have been invoked 6,7 . Here we report James Webb Space Telescope observations of CH 3 + in a protoplanetary disk in the Orion star-forming region. We find that gas-phase organic chemistry is activated by ultraviolet irradiation., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

The carriers of the diffuse interstellar bands (DIBs) are largely unidentified molecules ubiquitously present in the interstellar medium (ISM). After decades of study, two strong and possibly three weak near-infrared DIBs have recently been attributed to the [Formula: see text] fullerene based on observational and laboratory measurements. There is great promise for the identification of the over 400 other known DIBs, as this result could provide chemical hints towards other possible carriers. In an effort to systematically study the properties of the DIB carriers, we have initiated a new large-scale observational survey: the ESO Diffuse Interstellar Bands Large Exploration Survey (EDIBLES). The main objective is to build on and extend existing DIB surveys to make a major step forward in characterising the physical and chemical conditions for a statistically significant sample of interstellar lines-of-sight, with the goal to reverse-engineer key molecular properties of the DIB carriers. EDIBLES is a filler Large Programme using the Ultraviolet and Visual Echelle Spectrograph at the Very Large Telescope at Paranal, Chile. It is designed to provide an observationally unbiased view of the presence and behaviour of the DIBs towards early-spectral type stars whose lines-of-sight probe the diffuse-to-translucent ISM. Such a complete dataset will provide a deep census of the atomic and molecular content, physical conditions, chemical abundances and elemental depletion levels for each sightline. Achieving these goals requires a homogeneous set of high-quality data in terms of resolution ( R ~ 70 000 - 100 000), sensitivity (S/N up to 1000 per resolution element), and spectral coverage (305-1042 nm), as well as a large sample size (100+ sightlines). In this first paper the goals, objectives and methodology of the EDIBLES programme are described and an initial assessment of the data is provided.

Alzheimer's disease (AD) is among the most significant health care burdens. Disappointing results from clinical trials in late-stage AD persons combined with hopeful results from trials in persons with early-stage suggest that research in the preclinical stage of AD is necessary to define an optimal therapeutic success window. We review the justification for conducting trials in the preclinical stage and highlight novel ethical challenges that arise and are related to determining appropriate risk-benefit ratios and disclosing individuals' biomarker status. We propose that to conduct clinical trials with these participants, we need to improve public understanding of AD using unified vocabulary, resolve the acceptable risk-benefit ratio in asymptomatic participants, and disclose or not biomarker status with attention to study type (observational studies vs clinical trials). Overcoming these challenges will justify clinical trials in preclinical AD at the societal level and aid to the development of societal and legal support for trial participants., (Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.)

In recent decades, a number of molecules and diverse dust features have been identified by astronomical observations in various environments. Most of the dust that determines the physical and chemical characteristics of the interstellar medium is formed in the outflows of asymptotic giant branch stars and is further processed when these objects become planetary nebulae. We studied the environment of Tc 1, a peculiar planetary nebula whose infrared spectrum shows emission from cold and neutral C60 and C70. The two molecules amount to a few percent of the available cosmic carbon in this region. This finding indicates that if the conditions are right, fullerenes can and do form efficiently in space.

MDMA given at recreational doses (range tested 50 to 150 mg) to healthy volunteers, produced mydriasis and marked increases in systolic and diastolic blood pressure, heart rate, and pupillary diameter. MDMA induced changes on oral temperature. The time course of this observation was biphasic, as a slight decrease at 1 h and a slight increase at 2 and 4 h were observed. MDMA induced a slight dose-dependent impairment on psychomotor performance. MDMA produced a marked rise in plasma cortisol and prolactin concentrations. The elimination half-life of MDMA was about 8-9 h. Drug concentrations increased, and a parallel increase in physiologic and hormonal measures was observed. Both peak concentrations and peak effects were obtained between 1 and 2 h and decreased to baseline values 4-6 h after drug administration.

3,4-Methylenedioxymethamphetamine (MDMA, "ecstasy") is a recreational drug of increasing use among youth because of its apparent entactogenic properties, such as euphoria, friendliness, closeness, and empathy. However, experimental studies have shown MDMA to be neurotoxic. Data on pharmacologic actions of MDMA in humans are limited. The authors conducted a randomized, double-blind, crossover, controlled trial to assess psychomotor performance and subjective effects in eight healthy male volunteers. MDMA was given in the same range of doses used for recreational purposes (75 and 125 mg). Amphetamine (40 mg) and placebo were used as reference compounds. For the digit-symbol substitution test (DSST), MDMA-125 produced a mild decrease in responses, and amphetamine produced a mild improvement. For the Maddox wing device, MDMA-125 induced esophoria compared with the other drug conditions. MDMA-125 and MDMA-75 produced increases in feelings of euphoria and well-being, as noted by increases in scores on the Addiction Research Center Inventory (ARCI) MBG and A scales, as well as scores of "stimulated," "good effects," "liking," and "high" on the visual analog scales. Amphetamine administration induced similar effects. At the same time, MDMA-125 enhanced sedation- and dysphoria-related effects (ARCI-PCAG and LSD, "confusion," "drunken," and Profile of Mood States Confusion scale). Mild changes in some body perception-related feelings were also reported after MDMA use, but hallucinations or psychoses were not present. In summary, the short-term administration of MDMA produced marked euphoria, a slight impairment in the performance of psychomotor tasks, and mild changes in body perceptions without hallucinations. These data support the abuse liability of MDMA.

The simultaneous administration of cocaine and alcohol implies a pharmacological interaction at pharmacodynamic and pharmacokinetic levels. The latter involves an alteration of cocaine kinetics and metabolism, as well as the biosynthesis of newly active metabolites, such as cocaethylene. Cocaethylene is metabolized along the same pathways as cocaine. Its detection in biological samples indicates the combined consumption of cocaine and alcohol. From epidemiological and toxicological data, it has been suggested that the combination of alcohol and cocaine produces an increased toxicity in addition to behavioral changes. There has been some debate regarding the contribution of cocaethylene to this rise of toxicity. Its pharmacological and toxicological profile is very similar to cocaine. During the interaction of both substances, the rise in cocaine plasma concentrations can explain many of cardiovascular and behavioral effects observed. The contribution of cocaethylene to the interaction is probably minor; its effects are likely additive to those of cocaine. Perhaps its longer elimination half-life can help in understanding long-lasting effects of the alcohol-cocaine combination.

During the academic year 1983-1984, a survey on drug consumption was conducted among medical students in Barcelona. There was a high proportion of smokers in both sexes. Alcohol consumption was four times higher among men than women; high proof beverages were becoming the most common drinks. Coffee was the caffeine drink consumed by almost the whole population studied. Although cannabis derivatives had been tried at least once by almost all the students, regular consumers were almost non-existent. Amphetamine consumption was restricted to examination periods. The use of opiates, cocaine, hallucinogens, and solvents was rare for the sample. Results from this study are compared with those from similar surveys conducted 5 and 10 years ago.

A multicentre prospective study was performed in eight centres in Spain in order to assess the usefulness of naltrexone in the treatment of opiate dependents and abusers (113 dependents and 37 abusers) non-selected in terms of social class or professional skill. The fundamental criterion for evaluation of clinical outcome was the retention rate. At 6 months this parameter was 40%, i.e. higher than any previously reported for non-selected patients. The adverse effects were mild and did not lead to therapeutic failures. Non-pharmacological factors may have contributed to the good clinical results obtained.

A survey of medical students was conducted at the Universitat Autònoma de Barcelona in 1974. Out of 1029 students, 808 present at lectures (78.5%) returned properly completed questionnaires. These showed that mean caffeine consumption was 8.3 g per month and increased with the length of stay at the university. Tobacco consumption (general mean, 190 cigarettes per month, 216 for males and 150 for females) and alcohol consumption (8.8 litres/year for males and 4.1 litres/year for females) also increased with time spent at university. Alcohol consumption was not as high as in the general population. Amphetamine consumption was very high (22% of students had taken amphetamines on more than one occasion in the six months prior to the survey). Marihuana and hashish were by far the most commonly used drugs (9.6%), the use of these drugs being much less common than at other European universities. The use of "harder" drugs was very limited. Appraisal of alcohol, tobacco and amphetamine abuse is necessary, since the authorities have not employed adequate measures to stop or limit them.