Petrology and chemistry of the Miles IIE iron. II: Chemical characteristics of the Miles silicate inclusions

A total of nine silicate inclusions (6 gabbroic, 3 cryptocrystalline) were isolated from slab samples of the Miles IIE iron meteorite. They were studied petrologically and then analyzed by instrumental neutron activation analysis, along with the host metal. Based on the siderophile element abundances in the host metal phase, Miles can be classified as a IIE iron but in some aspects it does not match the siderophile abundances of either IIE or anomalous IIE (IIE-An) irons. It may be a member of a third group of IIE irons, tentatively named fractionated IIE. Compared with the average H chondrite, the highly siderophile elements (Re, Os, Ir) are relatively more depleted than the less refractory siderophiles, except for Cu which is as depleted as the highly siderophile elements. This suggests that the metal phase of Miles was not simply produced by a vaporization/fractional condensation process. Rather, it was produced by the melting of H chondritic materials, followed by melt-solid segregation. At least a part of the immiscible sulfide in which Cu was distributed to a considerable degree, was removed from the metal melt. Silicate inclusions have variable amounts of siderophile elements, but their relative abundances are similar to those of the metal phase. This suggests that the siderophile elements in the silicate inclusions have the same genesis as those in the host metal. Plagiophile elements (Al, Na and K) are all enriched in the silicate inclusions, especially in the cryptocrystalline inclusions, with K being the most abundant, successively followed by Na and Al. This fractionation of the plagiophile elements must have occurred during the fractional crystallization process, when the silicate inclusions formed. Rare earth elements (REE) are fairly enriched in the silicate inclusions (especially in the gabbroic inclusions) but their concentrations are slightly lower than that expected from the degree of partial melting of H chondritic materials. A mechanical loss of Ca-phosphate in sampling is suggested for the inconsistency in the REE abundances. Based on the REE abundance variations in the silicate inclusions of several IIE irons, including Miles, we infer that the degree of differentiation of the parental liquids from which silicate inclusions formed was highly variable; it increased from Watson to Weekeroo Station, with Miles being intermediate

Enclaves in the Mt.Padbury and Vaca Muerta mesosiderites: Magmatic and residue (or cumulate) rock types

Nine eucritic enclaves from mesosiderites and one possible enclave were petrologically and chemically studied. Three are from Mt. Padbury, six from Vaca Muerta, and one eucritic meteorite (AMNH 4627) was found in northern Chile and may be an enclave from Vaca Muerta. The enclaves studied were classified into two groups based on the presence or absence of primary ilmenite : (1) an Il-bearing group ranging in texture from medium-grained ophitic to coarse-grained gabbroic, and (2) an Il-free group from gabbroic to coarse-grained equigranular texture. Pigeonites of the Il-bearing group are more ferroan than those of the Il-free group. The peripheral portions of pigeonite in the Il-free group have remarkable textures not found in HED meteorites. They are replaced by more-magnesian hypersthene and troilite with a minor amount of silica-mineral, indicating that reduction of pigeonite took place by H_2S under subsolidus conditions prior to formation of the mesosiderite, metal-silicate mixing. The major element compositions of the ten whole rock samples indicate that the Il-bearing group is similar to the non-cumulate eucrites, but the Il-free group differs from the cumulate eucrites. The Il-free group is significantly enriched in silica-mineral component in comparison with the cumulate eucrites. INAA and RNAA analyses for five whole rock samples were performed. Two Il-free enclaves have low REE contents with remarkable positive Eu-anomalies (chondrite-normalized Eu/Sm=13.6), and two Il-bearing enclaves have higher REE contents with slight positive Eu-anomalies (chondrite-normalized Eu/Sm=1.88-2.22). The high Eu/Sm ratios are partly due to terrestrial alteration of whitlockites, and the original Eu/Sm ratios of the Il-bearing and Il-free enclaves might be similar to those of non-cumulate eucrites and cumulate eucrites, respectively. These suggest that the Il-bearing enclaves were formed in the similar way to the non-cumulate eucrites, and the Il-free enclaves formed as cumulates from silica-rich magmas or as residues by partial melting of silica-bearing cumulate eucritic sources. A eucritic sample (AMNH 4627) has the highest REE content with no Eu-anomaly and is similar to the non-cumulate eucrites, and may be an independent eucrite

Petrological and geochemical study of the Yamato-74359 and Yamato-74360 achondrites

Two Antarctic achondrites, Yamato (Y)-74359 and Y-74360,are very similar in bulk chemical compositions to the silicate portions of H chondrites, but the siderophile elements are extremely depleted in comparison to those of H chondrites. They consist of olivine, pyroxene and cryptocrystalline feldspar with minor amounts of chromite, kamacite, and troilite, and the chemical compositions of the constituent minerals are similar to those in H chondrites. Taking into consideration that the two achondrites have oxygen isotopic compositions typical of H chondrites, they were produced from H chondrites or the precursors of H chondrites. Chondrules are not observed, and the texture of the two achondrites is similar to one another, although Y-74360 is coarser-grained than Y-74359. Olivine occurs as euhedral or subhedral grains, mostly smaller than 100 microns in diameter, and they show slight chemical zoning, from magnesian cores (Fo_) to ferroan rims (Fo_). Orthopyroxene occurs as euhedral grains, larger than olivine grains, and also shows slight chemical zoning, from Ca-poorer magnesian cores to Ca-richer ferroan rims. Clinopyroxene occurs as rims of orthopyroxenes and shows remarkable chemical zoning continuously from pigeonitic interiors to augitic rims. Cryptocrystalline feldspar occurs in interstitial spaces between olivine and/or pyroxene, and seems to have crystallized in interstitial liquids in a rapid cooling condition. The cryptocrystalline feldspars in Y-74359 are chemically heterogeneous, classified into three groups, albite (An_Ab_Or_), anorthoclase (An_Ab_Or_), and intermediate alkali feldspar (An_Ab_Or_), and occur in different portions of the thin section. The two achondrites seem to have formed by partial melting from heterogeneous silicate precursors of unequilibrated H chondrites

Petrology and chemistry of the Miles IIE iron. I: Description and petrology of twenty new silicate inclusions

A petrologic study of twenty new silicate inclusions (15 gabbroic, 5 cryptocrystalline) in the Miles IIE iron was undertaken in order to help clarify the petrogenesis of this meteorite and its relationship to other IIE irons with silicates, as well as H-group chondrites. Nine of the inclusions were analyzed by the INAA method, which is presented in a companion paper. The results indicate that Miles was formed by shock events on an H-group chondrite parent body. It formed silicate melt and Fe-Ni-S-P melt by about 25% partially melting, and left behind olivine-orthopyroxene residues. The silicate melt was a crystal mush which consisted of phenocrysts of high-Ca pyroxene, orthopyroxene and plagioclase, and residual melt. The phenocryst-enriched mush formed irregular-shaped gabbroic inclusions, which also contain minor olivine, inverted pigeonite, antiperthite, K-feldspar, tridymite, glass, chromite, rutile, ilmenite, armalcolite, chlorapatite, whitlockite, kamacite, taenite, schreibersite, troilite and pentlandite. The residual melt formed round- to ellipsoidal-shaped cryptocrystalline inclusions, which contain microphenocrysts of alkali feldspar or phenocrysts of pyroxene. The crystal mush was mixed with abundant Fe-Ni-S-P melt, from which most of the sulfur escaped, and from which some of the phosphorus reacted with the silicate melts, resulting in their reduction. This reduction produced Ca-poor magnesian orthopyroxene and Ca-poor plagioclase in the gabbroic inclusions. The degree of reduction was, however, more intense in the cryptocrystalline inclusions than in the gabbroic inclusions. The remaining phosphorus in the solid host metal exsolved as schreibersite around the silicate inclusions

Novel Lung Growth Strategy with Biological Therapy Targeting Airway Remodeling in Childhood Bronchial Asthma

Anti-inflammatory therapy, centered on inhaled steroids, suppresses airway inflammation in asthma, reduces asthma mortality and hospitalization rates, and achieves clinical remission in many pediatric patients. However, the spontaneous remission rate of childhood asthma in adulthood is not high, and airway inflammation and airway remodeling persist after remission of asthma symptoms. Childhood asthma impairs normal lung maturation, interferes with peak lung function in adolescence, reduces lung function in adulthood, and increases the risk of developing chronic obstructive pulmonary disease (COPD). Early suppression of airway inflammation in childhood and prevention of asthma exacerbations may improve lung maturation, leading to good lung function and prevention of adult COPD. Biological drugs that target T-helper 2 (Th2) cytokines are used in patients with severe pediatric asthma to reduce exacerbations and airway inflammation and improve respiratory function. They may also suppress airway remodeling in childhood and prevent respiratory deterioration in adulthood, reducing the risk of COPD and improving long-term prognosis. No studies have demonstrated a suppressive effect on airway remodeling in childhood severe asthma, and further clinical trials using airway imaging analysis are needed to ascertain the inhibitory effect of biological drugs on airway remodeling in severe childhood asthma. In this review, we describe the natural prognosis of lung function in childhood asthma and the risk of developing adult COPD, the pathophysiology of allergic airway inflammation and airway remodeling via Th2 cytokines, and the inhibitory effect of biological drugs on airway remodeling in childhood asthma

New enclaves in the Vaca Muerta mesosiderite: Petrogenesis and comparison with HED meteorites

Thirty-eight new enclaves from the Vaca Muerta mesosiderite have been studied, and detailed SEM-petrography was carried out on fourteen of them. Three are coarse-grained gabbroic ilmenite-free enclaves consisting mainly of pigeonite (En_) and plagioclase, seven are fine- to medium-grained ilmenite-bearing enclaves (En_) with ophitic to granular texture, and four are breccias. The most important breccias are diogenitic monomict breccias (En_) and an olivine-orthopyroxenite monomict breccia (Fo_). Reduction-induced orthopyroxene commonly surrounds pigeonite grains in the ilmenite-free enclaves, and occurs rarely in the marginal parts of the ilmenite-bearing enclaves. Whitlockite forms from augite lamellae as a result of reduction, and the ilmenite-free enclaves have been enriched in P_2O_5. Reduction of the ilmenite-free enclaves occurred in the parent body before mixing with Fe-Ni metal on the mesosiderite parent body. In the ilmenite-bearing enclaves reduction occurred on the mesosiderite parent body after Fe-Ni metal was mixed in. Thus, two stages of subsolidus reduction occurred in enclaves. Ilmenite and rutile occur in the ilmenite-bearing and diogenitic enclaves, and various subsolidus reaction textures of chromite, ilmenite, rutile and probably preexisting pseudobrookite are found. Al_2O_3-depleted chromite formed through the decomposition of Cr_2O_3-bearing ilmenite and pseudobrookite. Zircon and baddeleyite were also found in the ilmenite-bearing enclaves, and the latter is the first occurrence reported in mesosiderites. The ilmenite-bearing enclaves always contain baddeleyite, whereas ZrO_2-bearing phases are hardly ever found in HED meteorites. The bulk compositions of the enclaves were analyzed, and found to be more SiO_2-enriched than the HED meteorites. Highly SiO_2-enriched ilmenite-bearing enclaves are especially common, and follow the Nuevo Laredo trend of the eucrites, whereas the other ilmenite-bearing enclaves follow the Stannern trend. The highly SiO_2-enriched enclaves probably formed by fractional crystallization, whereas the other ilmenite-bearing enclaves formed through partial melting. The existence of the highly SiO_2-enriched enclaves may partly explain the SiO_2-rich nature of mesosiderites, in addition to the in situ reduction process. Our observations suggest that the parent body and the parental magmas of the enclaves in the mesosiderites were initially different from those of the HED meteorites

Severe pediatric asthma with a poor response to omalizumab: a report of three cases and three-dimensional bronchial wall analysis

Omalizumab is used for the treatment of persistent severe allergic asthma in adults and children. However, some patients remain symptomatic even after omalizumab treatment. In bronchial asthma, chronic inflammation of the bronchial wall causes thickening of the airway wall, resulting from irreversible airway remodeling. Progression of airway remodeling causes airflow obstruction, leading to treatment resistance. We report three Japanese children with severe asthma who had a poor response to omalizumab treatment. They had a long period of inadequate management of asthma before initiating omalizumab. Even after omalizumab treatment, their symptoms persisted, and the parameters of spirometry tests did not improve. We hypothesized that omalizumab was less effective in these patients because airway wall remodeling had already progressed. We retrospectively evaluated the bronchial wall thickness using a three-dimensional bronchial wall analysis with chest computed tomography. The bronchial wall thickness was increased in these cases compared with six responders. Progressed airway wall thickness caused by airway remodeling may be associated with a poor response to omalizumab in children with severe asthma

Anaphylaxis after jellyfish ingestion with no history of stings: a pediatric case report

Background Jellyfish stings are known to induce allergic skin reactions; however, case reports of anaphylaxis after jellyfish ingestion have been increasing, especially in Asian countries. Some cases of anaphylaxis after jellyfish ingestion have been reported in patients with a previous history of frequent jellyfish stings. Herein, we report a pediatric patient with anaphylaxis after jellyfish ingestion with no history of jellyfish stings. Case presentation A 14-year-old girl developed two episodes of anaphylaxis, and her diet diaries revealed that edible jellyfish was common to the meals in both the anaphylaxis events. A skin prick test using five types of edible jellyfish products revealed a positive reaction to some jellyfish, and anaphylaxis was observed after the ingestion of jellyfish in an oral food challenge test. She had no history of jellyfish stings or frequent swimming in the ocean. The basophil activation test showed positive results on stimulation with extracts from various types of edible jellyfish. We observed serum immunoglobulin E (IgE) reactivity to purified jellyfish collagen and jellyfish acid-soluble extracts. Moreover, immunoblotting analysis showed IgE reactivity to two bands at approximately 40 and 70 kDa using purified jellyfish collagen, which may be a causative antigen. Conclusions Edible salted jellyfish can be one of the causative foods of anaphylaxis. Clinicians should be aware of the possibility of anaphylactic reactions due to jellyfish ingestion even without a history of jellyfish stings