The Discovery of a Low-energy Excess in Cosmic-Ray Iron: Evidence of the Past Supernova Activity in the Local Bubble.

Since its launch, the Alpha Magnetic Spectrometer-02 (AMS-02) has delivered outstanding quality measurements of the spectra of cosmic-ray (CR) species ( p ¯ , e ±, and nuclei, 1H-8O, 10Ne, 12Mg, 14Si) which resulted in a number of breakthroughs. One of the latest long-awaited surprises is the spectrum of 26Fe just published by AMS-02. Because of the large fragmentation cross section and large ionization energy losses, most of CR iron at low energies is local and may harbor some features associated with relatively recent supernova (SN) activity in the solar neighborhood. Our analysis of the new AMS-02 results, together with Voyager 1 and ACE-CRIS data, reveals an unexpected bump in the iron spectrum and in the Fe/He, Fe/O, and Fe/Si ratios at 1-2 GV, while a similar feature in the spectra of He, O, and Si and in their ratios is absent, hinting at a local source of low-energy CRs. The found excess extends the recent discoveries of radioactive 60Fe deposits in terrestrial and lunar samples and in CRs. We provide an updated local interstellar spectrum (LIS) of iron in the energy range from 1 MeV nucleon-1 to ~10 TeV nucleon-1. Our calculations employ the GALPROP-HELMOD framework, which has proved to be a reliable tool in deriving the LIS of CR p ¯ , e -, and nuclei Z ⩽ 28.

Erratum: "Inference of the Local Interstellar Spectra of Cosmic-Ray Nuclei Z ⩽ 28 with the GALPROP-HELMOD Framework" (2020, ApJS, 250, 27).

[This corrects the article PMC8549769.].

Deciphering the Local Interstellar Spectra of Secondary Nuclei with the Galprop/Helmod Framework and a Hint for Primary Lithium in Cosmic Rays.

Local interstellar spectra (LIS) of secondary cosmic-ray (CR) nuclei, lithium, beryllium, boron, and partially secondary nitrogen, are derived in the rigidity range from 10 MV to ~200 TV using the most recent experimental results combined with state-of-the-art models for CR propagation in the Galaxy and in the heliosphere. The lithium spectrum appears somewhat flatter at high energies compared to other secondary species, which may imply a primary lithium component. Two propagation packages, GALPROP and HelMod, are combined to provide a single framework that is run to reproduce direct measurements of CR species at different modulation levels, and at both polarities of the solar magnetic field. An iterative maximum-likelihood method is developed that uses GALPROP-predicted LIS as input to HelMod, which provides the modulated spectra for specific time periods of the selected experiments for the model-data comparison. The proposed LIS accommodates the low-energy interstellar spectra measured by Voyager 1, the High Energy Astrophysics Observatory-3 (HEAO-3), and the Cosmic Ray Isotope Spectrometer on board of the Advanced Composition Explorer (ACE/CRIS), as well as the high-energy observations by the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA), Alpha Magnetic Spectrometer-02 (AMS-02), and earlier experiments that are made deep in the heliosphere. The interstellar and heliospheric propagation parameters derived in this study are consistent with our earlier results for propagation of CR protons, helium, carbon, oxygen, antiprotons, and electrons.

Inference of the Local Interstellar Spectra of Cosmic-Ray Nuclei Z ⩽ 28 with the GalProp-HelMod Framework.

Composition and spectra of Galactic cosmic rays (CRs) are vital for studies of high-energy processes in a variety of environments and on different scales, for interpretation of γ-ray and microwave observations, for disentangling possible signatures of new phenomena, and for understanding of our local Galactic neighborhood. Since its launch, AMS-02 has delivered outstanding-quality measurements of the spectra of p ¯ , e ±, and nuclei: 1H-8O, 10Ne, 12Mg, 14Si. These measurements resulted in a number of breakthroughs; however, spectra of heavier nuclei and especially low-abundance nuclei are not expected until later in the mission. Meanwhile, a comparison of published AMS-02 results with earlier data from HEAO-3-C2 indicates that HEAO-3-C2 data may be affected by undocumented systematic errors. Utilizing such data to compensate for the lack of AMS-02 measurements could result in significant errors. In this paper we show that a fraction of HEAO-3-C2 data match available AMS-02 measurements quite well and can be used together with Voyager 1 and ACE-CRIS data to make predictions for the local interstellar spectra (LIS) of nuclei that are not yet released by AMS-02. We are also updating our already-published LIS to provide a complete set from 1H-28Ni in the energy range from 1 MeV nucleon-1 to ~100-500 TeV nucleon-1, thus covering 8-9 orders of magnitude in energy. Our calculations employ the GalProp-HelMod framework, which has proved to be a reliable tool in deriving the LIS of CR p ¯ , e -, and nuclei 1H-8O.

HelMod in the Works: From Direct Observations to the Local Interstellar Spectrum of Cosmic-Ray Electrons.

The local interstellar spectrum (LIS) of cosmic-ray (CR) electrons for the energy range 1 MeV to 1 TeV is derived using the most recent experimental results combined with the state-of-the-art models for CR propagation in the Galaxy and in the heliosphere. Two propagation packages, GALPROP and HelMod, are combined to provide a single framework that is run to reproduce direct measurements of CR species at different modulation levels, and at both polarities of the solar magnetic field. An iterative maximum-likelihood method is developed that uses GALPROP-predicted LIS as input to HelMod, which provides the modulated spectra for specific time periods of the selected experiments for model-data comparison. The optimized HelMod parameters are then used to adjust GALPROP parameters to predict a refined LIS with the procedure repeated subject to a convergence criterion. The parameter optimization uses an extensive data set of proton spectra from 1997 to 2015. The proposed CR electron LIS accommodates both the low-energy interstellar spectra measured by Voyager 1 as well as the high-energy observations by PAMELA and AMS-02 that are made deep in the heliosphere; it also accounts for Ulysses counting rate features measured out of the ecliptic plane. The interstellar and heliospheric propagation parameters derived in this study agree well with our earlier results for CR protons, helium nuclei, and anti-protons propagation and LIS obtained in the same framework.

Deciphering the Local Interstellar Spectra of Primary Cosmic-Ray Species with helmod.

Local interstellar spectra (LIS) of primary cosmic ray (CR) nuclei, such as helium, oxygen, and mostly primary carbon are derived for the rigidity range from 10 MV to ~200 TV using the most recent experimental results combined with the state-of-the-art models for CR propagation in the Galaxy and in the heliosphere. Two propagation packages, GALPROP and helmod, are combined into a single framework that is used to reproduce direct measurements of CR species at different modulation levels, and at both polarities of the solar magnetic field. The developed iterative maximum-likelihood method uses GALPROP-predicted LIS as input to helmod, which provides the modulated spectra for specific time periods of the selected experiments for model-data comparison. The interstellar and heliospheric propagation parameters derived in this study are consistent with our prior analyses using the same methodology for propagation of CR protons, helium, antiprotons, and electrons. The resulting LIS accommodate a variety of measurements made in the local interstellar space (Voyager 1) and deep inside the heliosphere at low (ACE/CRIS, HEAO-3) and high energies (PAMELA, AMS-02).

Solution of Heliospheric Propagation: Unveiling the Local Interstellar Spectra of Cosmic-ray Species.

Local interstellar spectra (LIS) for protons, helium, and antiprotons are built using the most recent experimental results combined with state-of-the-art models for propagation in the Galaxy and heliosphere. Two propagation packages, GALPROP and HelMod, are combined to provide a single framework that is run to reproduce direct measurements of cosmic-ray (CR) species at different modulation levels and at both polarities of the solar magnetic field. To do so in a self-consistent way, an iterative procedure was developed, where the GALPROP LIS output is fed into HelMod, providing modulated spectra for specific time periods of selected experiments to compare with the data; the HelMod parameter optimization is performed at this stage and looped back to adjust the LIS using the new GALPROP run. The parameters were tuned with the maximum likelihood procedure using an extensive data set of proton spectra from 1997 to 2015. The proposed LIS accommodate both the low-energy interstellar CR spectra measured by Voyager 1 and the high-energy observations by BESS, Pamela, AMS-01, and AMS-02 made from the balloons and near-Earth payloads; it also accounts for Ulysses counting rate features measured out of the ecliptic plane. The found solution is in a good agreement with proton, helium, and antiproton data by AMS-02, BESS, and PAMELA in the whole energy range.

Histamine H(3)-receptor antagonists inhibit gastroprotection by (R)-alpha-methylhistamine in the rat.

(R)-alpha-methylhistamine, a selective agonist of histamine H(3) receptors, is capable of protecting the gastric mucosa against differently acting damaging agents. The objective of the present study was to determine whether H(3) receptors mediate its protective action in the rat. Gastric mucosal lesions were induced intragastrically (i.g.) by 0.6 N HCl, 1 ml rat(-1). (R)-alpha-methylhistamine, 100 mg kg(-1) i.g., substantially reduced the severity of macroscopically and histologically assessed damage caused by concentrated acid. Prior treatment with highly selective H(3)-receptor antagonists, ciproxifan (0.3, 1 and 3 mg kg(-1) i.g.) and clobenpropit (3, 10 and 30 mg kg(-1) i.g.), dose-dependently inhibited the protection exerted by (R)-alpha-methylhistamine up to a complete reversal. When given alone at high doses, both antagonists tended to worsen the HCl-induced histologic damage. During basal conditions, (R)-alpha-methylhistamine, 100 mg kg(-1) i. g., caused a significant increase in titratable acidity of the gastric juice. Prior treatment with ciproxifan (3 mg kg(-1) i.g.) and clobenpropit (30 mg kg(-1) i.g.) did not alter the secretory response to (R)-alpha-methylhistamine. Clobenpropit alone, but not ciproxifan, increased the volume of gastric juice, and both compounds alone had no effect on titratable acid. Present findings support evidence that H(3) receptors are actively involved in the maintenance of gastric mucosal integrity, with no apparent role in the regulation of basal gastric acid secretion.

Indomethacin-induced morphological changes in the rat gastric mucosa, with or without prior treatment with two proton pump inhibitors.

BACKGROUND: The mechanisms responsible for the gastric ulcerogenic effect of indomethacin are unclear. The importance of basal acid secretion on morphological changes by indomethacin was investigated. METHODS: Gastric lesions were macroscopically evaluated 6 h after indomethacin, 20 mg/kg intragastrically, in rats pre-treated with omeprazole (10-100 mumol/kg intragastrically) or lansoprazole (3-30 mumol/kg intragastrically). Glandular mucosa was processed for light, scanning and transmission electron microscopy 3 and 6 h after indomethacin in rats pre-treated with omeprazole (100 mumol/kg) or lansoprazole (30 mumol/kg). RESULTS: After 3 h, indomethacin caused extensive vasocongestion, oedema in the subepithelial region and superficial erosions. After 6 h, deeply extending focal necrosis involved 11% of the tissue. Leukocyte margination was occasionally seen at 3 h and consistently present at 6 h. Only at 6 h were endothelial cells altered. In rats pre-treated with omeprazole (100 mumol/kg) or lansoprazole (30 mumol/kg) grossly visible lesions were prevented. Oedema, erosions and necrosis were absent. Vasocongestion, vascular leakage and leukocytic margination were seen both at 3 and 6 h while no major damage of endothelial cells was observed. CONCLUSION: Indomethacin appears primarily to alter microcirculation, and microcirculation damage is dependent on acid for the progression to haemorrhagic lesions.

Rapid onset of (R)-alpha-methylhistamine protection in response to ethanol-induced histologic damage in rat gastric mucosa.

The influence of pretreatment with (R)-alpha-methylhistamine, selective agonist of histamine H3 receptors, has been investigated on gastric mucosal lesions at different time intervals, from 5 to 60 minutes, after administration of absolute ethanol in the rat. The amount and depth of lesions were quantitatively evaluated by light microscopy. In rats pretreated with (R)-alpha-methylhistamine, the integrity of the mucosa was preserved in approximately 80% of the total mucosal length measured despite ethanol challenge. Prevention of lesion formation was as great at 5 min after ethanol administration as at 60 min. When present, damage involved mainly superficial mucosa and lesions extending deeply into the gland region were evident in 1-2.5% of the total mucosa. Present findings indicate that mechanisms by which (R)-alpha-methylhistamine operates enable the mucosa to counteract damage just from the moment of exposure to ethanol and that protection is exerted both on surface and pit cells and on gastric glands.

Role of histamine H3 receptors in the regulation of gastric functions.

The role of central and peripheral histamine H3 receptors in the regulation of gastric acid secretion and gastric mucosal integrity is reviewed. The activation of H3 receptors by peripheral administration of the selective agonist (R)alpha-methylhistamine reduced acid secretion in cats, dogs, rats and rabbits, while increasing it in mice. The antisecretory effects were observed against indirect stimuli that act on vagal pathways or on enterochromaffin-like (ECL) cells, such as 2-deoxy-D-glucose, food or pentagastrin, but not against histamine or dimaprit. Inhibitory effects on acid production were observed in rats after central administration of histamine or of H3 receptor agonists. In the conscious rat intragastric administration of (R)alpha-methylhistamine caused gastroprotective effects against the damage induced by absolute ethanol, HCl, aspirin and stress. The mechanism involved seems to be related to the increased mucus production, via nitric oxide-independent mechanisms. Gastroprotective effects against ethanol were also observed after central administration of histamine or its metabolite N(alpha)-methylhistamine, suggesting that brain receptors participate the histamine-mediated effects on gastric functions.

Ultrastructural damage of the pulmonary endothelial cell after storage in lung preservation solutions. Comparison between Belzer and Euro-Collins solutions.

UNLABELLED: The preservation of the lung for transplantation for a long period is still a problem not solved. Euro-Collins (EC) and Belzer (UW) solution are the most widely used. The aim of this work is to analyse the direct influence of both EC and UW solutions on endothelial cells of human pulmonary artery by means of an ultrastructural analysis. The arteries were obtained from 3 patients that underwent pneumonectomy and prepared with the no touch technique. The arteries were divided in 15 specimens and preserved in EC and UW solution at 4 degrees C for 6 and 10 hours. The specimens were fixed in osmic acid veronal buffer 1% and embedded in Durcupan. Ultrastructural examination was done with transmission electron microscopy (TEM) and the influence of the solutions was evaluated using a grading scale with scores ranging from 0 to 4 that express the damages of the cellular wall, mitochondria and nuclei. The data are expressed as mean +/- standard deviation (n = 5). Student's t-test was used for statistical comparison between the solutions. RESULTS: after 6 hours of preservation in EC and UW the scores were 5.2 +/- 0.45 and 4.8 +/- 0.84 (p = 0.373) while after 10 hours were respectively 8.2 +/- 0.84 and 6.8 +/- 0.84 (p = 0.029). In conclusion our experimental model suggests that there are no significant differences between EC and UW after hypothermic 6 hours preservation while endothelial cells are better preserved after 10 hours in UW solution.

Season related ultrastructural features of the parotid, submandibular and von Ebner's glands in hibernating bats.

The parotid, submandibular and the von Ebner's salivary glands of hibernating insectivorous bats (Pipistrellus pipistrellus, Rhinolophus f. e. and Eptesicus serotinus) were studied by transmission electron microscopy and by histochemical methods during various seasons of the year. We report the seasonal ultrastructural changes that occur in the cytoplasmic organelles and the secretory granules of the serous and mucous cells and in the intercalated and striated ducts of the major glands. It previously has been hypothesized that the heterogeneity of the inclusions in the serous granules is closely related to the varying seasonal levels of proteinaceous and glycidic constituents. Lymphatic vessels are present only in the perivascular and periductal connective tissue. Morphofunctional and comparative studies seem to confirm a relationship between secretory activity and nutritional status as well as a likely involvement of the intercalated and striated ducts in determining the composition of the saliva.

On the myoepithelium of human salivary glands. An immunocytochemical study.

This study investigated the immunocytochemical characteristics of normal myoepithelial cells (MECs) of human major and minor salivary glands using the LSAB method. Other human exocrine glands were used as controls. Immunoreactivity of MECs was observed exclusively with fully differentiated smooth muscle antibodies (a-SMA; SMMS-1; CALP; hCD) and with epithelial markers (cytokeratins) Ck14 and Ck17. This epithelial-muscular immunophenotype was similarly expressed in the MECs of other human exocrine glands used as control. In the salivary MECs, we did not observe evidence for neuroectodermic phenotype (S-100 protein, GFAP, NSE). On the contrary, positivity was observed for S-100 protein in Mecs of control glands (mammary, bronchial and sweat glands). Immunoreaction for extracellular matrix markers (fibronectin, laminin and collagen IV) and vimentin always were negative. Our data show that in normal "non transformed" MECs of the salivary glands the smooth muscle phenotype is in a state of complete differentiation, while the epithelial phenotype expresses only Ck14 and Ck17. This double and simultaneous immunoreactivity represents a differential marker of MECs from the epithelial basal cell (EBCs).

Long-term study of TNBS-induced colitis in rats: focus on mast cells.

OBJECTIVE AND DESIGN: To investigate the severity and duration of colitis induced by two different doses of 2,4,6-trinitrobenzenesulfonic acid (TNBS) and the changes in mast cell number in acute inflammation and in the recovery process of colitis. METHODS: Colitis was induced in rats by an enema of TNBS (10 or 30 mg) in 25% ethanol. Macroscopic and histologic changes of the colon, colon weight and mast cell counts were examined at various times (7, 30 and 60 days) after colitis induction. RESULTS: TNBS induced a colonic damage which was dose-related for both severity and time necessary to complete recovery. On day 7 after colitis induction 10 mg TNBS induced macroscopic and microscopic alterations of colonic architecture that completely resolved at day 60. By contrast, 30 mg TNBS induced massive necrosis, thickening of the colon, severe histologic changes that were only partially reversed after two months. Mast cell number in the submucosa and muscularis propria decreased significantly in the acute phase of inflammation (7 days) and slowly increased thereafter, reaching a maximum level (up to about 5-fold) at day 60 after both doses of TNBS. CONCLUSIONS: Present data confirm the ability of TNBS to induce in rats damage to the colon that was dose-dependent for severity and duration. Moreover, these data unravel a different role of mast cells in TNBS-induced colitis: an early degranulation in the acute phase of inflammation and a subsequent accumulation of mast cells in the late phase of the disease, associated with tissue repair.

The pineal body of the mink and horse with special reference to the reproductive cycle. An ultrastructural and immunocytochemical study.

An ultrastructural and immunohistochemical analysis was performed on the epiphysis of two species of mammals: mink and horse. These animals present a reproductive cycle that varies along the year according to the light exposition. The aim of the study was to define possible structural changes connected with the gonadal activity. Structural aspects in common emerged such as those in concern with the epiphysis cells, their immunocytochemical characteristics (NSE and Synaptophysin positivity of pinealocytes, as well as CFAP positivity of further cells), and those in concern with the general ultrastructure. This latter has in particular revealed significant differences in relation to the biological cycles considered. In the presence of gonadal activity the mink pinealocyte displays a modest cytological organization which, on the contrary, after the mating and in arrest of the gonadal activity, appears as fully restored. In the horse, in both natural and artificially induced photoperiods, significant variations were noted these in connection with the various phases of development of the electron-dense granules, typical of the horse pinealocyte, interpreted as melanosomes. These aspects confirm the role of the epiphysis in the regulation of the reproductive cycle, albeit in the presence of species-specific peculiarities.

[Histological changes in the rat testis and epididymis caused by total and partial pinealectomy]. / Modificazioni istologiche del testicolo e dell'epididimo di ratto da epifisectomia totale e parziale.

Histological changes of testis and epididymis after partial and total pinealectomy in albino rat have been studied. After 8 and 16 days from total pinealectomy, testicular parenchyma showed morphological aspects of hypotrophy characterized by the absence of spermatozoa in tubular lumen and by tubules lined by an immature seminiferous epithelium. At the 21st day we have noticed a restoration of normal spermatogenesis. Leydig and Sertoli cells did not state significative modifications. After 8 and 16 days from the operation epididymal canalicula presented a narrowed lumen, lined by a pseudostratified columnar epithelium and occupied by numerous immature spermatogenic cells. After partial epiphysectomy we did not notice any significative modification both in the testicular and epididymal parenchyma. A participation of epiphysis cerebri in temporal regulation of spermatogenesis in albino rat male gonads has been hypothesized.

[Fine structure of the parathyroid gland of the fresh water turtle (Pseudemys scripta)]. / Sulla fine struttura della paratiroide di tartaruga di acqua dolce (Pseudemys scripta).

The ultrastructural characteristics of parathyroid in fresh-water turtles (Pseudemys scripta) are studied during the four seasons of the year. The gland parenchyma consists of chief cells organized in solid cordons. No oxifil cell is seen in turtle parathyroid. The chief cells present seasonal variations in cytoplasmatic organization. These are essentially represented by: the presence of secretory granules, cilia with centriolar apparatus and microfilaments in autumn; middle and wide lipid vacuoles and glycogen particles in winter; light and dark chief cells in spring. The dates, described above, suggest that seasonal variations of parathyroid in fresh-water turtles can be correlated with ultrastructural parathyroid aspects of hibernant animals.

[Seasonal variations of the ultimobranchial body of the turtle (Pseudemys scripta)]. / Sulle modificazioni cicliche stagionali del corpo ultimobranchiale di tartaruga (Pseudemys scripta).

Ultrastructural seasonal cyclic aspects of ultimobranchial body (C.U.B.) in fresh turtles (Pseudemys scripta) are studied. The C.U.B. consists of follicles and cords. The cord cells are characterized by many secretory granules measuring approximately 180 nm with variable feature and electron density. These granules are localized in the cytoplasm close to basal laminae. The follicular cells, on the contrary, present few and large secretory granules, glycogen particles, bundle of filaments and a scarcely developing Golgi apparatus and granular endoplasmic reticulum. The apical and follicular cytoplasmatic membrane is provided with small number of cilia and short microvilli. Seasonal cellular variations are described clearly in the winter (february-march) specimens of ultimobranchial body, these are characterized by more cord aspects and few follicles. The only cord cells present significant ultrastructural changes, represented by more glycogen particles, middle and wide lipid droplets and poor presecretory granules in Golgi zone. These morphological elements orient to a parallelism with the C cells of hibernant animals (Azzali 1967, Frink and Coll.) and the chief cells of parathyroid gland of the self turtle species as by our previous study.

[Ultrastructural aspects of testicular interstitial cells in the bat (Vesperugo savi)]. / Aspetti ultrastrutturali delle cellule interstiziali del testicolo di pipistrello (Vesperugo savi).

The fine structure of the testicular interstitial cells (Leydig cells) was studied in the bat (Vesperugo savi) during the seasons in connection with his peculiar spermatogenesis activity and biologic cycle. Such cells have ultrastructural aspects similar to those delineated for the other species. Only the smooth endoplasmatic reticulum, mitochondria and lipid droplets changes their morphologic features during the year. In fact in the summer-autumn season there is an intense spermatogenesis. The Leydig cells show more developed smooth endoplasmatic reticulum and lipid droplets of different size of peripheral electron-density. During the winter-spring season there is not spermatogenesis. The testicular interstitial cells have a poor smooth endoplasmatic reticulum and numerous bodies like lipofuscin pigments. When the bat wakes from his lethargic sleep, the ultrastructural aspects of Leydig cells are the prove of a smaller synthesis activity. These results confirm the dependence of testicular interstitial cells from the spermatogenic cycle.