Progressive veining during peridotite carbonation: insights from listvenites in Hole BT1B, Samail ophiolite (Oman)

The reaction of serpentinized peridotites with CO2-bearing fluids to listvenite (quartz-carbonate rocks) requires massive fluid flux and significant permeability despite increase in solid volume. Listvenite and serpentinite samples from Hole BT1B of the Oman Drilling Project help to understand mechanisms and feedbacks during vein formation in this process. Samples analyzed in this study contain abundant magnesite veins in closely spaced, parallel sets and younger quartz-rich veins. Cross-cutting relationships suggest that antitaxial, zoned carbonate veins with elongated grains growing from a median zone towards the wall rock are among the earliest structures to form during carbonation of serpentinite. Their bisymmetric chemical zoning of variable Ca and Fe contents, a systematic distribution of SiO2 and Fe-oxide inclusions in these zones, and cross-cutting relations with Fe-oxides and Cr-spinel indicate that they record progress of reaction fronts during replacement of serpentine by carbonate in addition to dilatant vein growth. Euhedral terminations and growth textures of carbonate vein fill together with local dolomite precipitation and voids along the vein – wall rock interface suggest that these antitaxial veins acted as preferred fluid pathways allowing infiltration of CO2-rich fluids necessary for carbonation to progress. Fluid flow was probably further enabled by external tectonic stress, as indicated by closely spaced sets of subparallel carbonate veins. Despite widespread subsequent quartz mineralization in the rock matrix and veins, which most likely caused a reduction in the permeability network, carbonation proceeded to completion in listvenite horizons.

Quantifying EpCAM heterogeneity of circulating-tumor-cells (CTCs) from small cell lung cancer (SCLC) patients.

e20091 Background: Tumor heterogeneity and evolution of SCLC is poorly defined. Serial longitudinal interrogation of tumor heterogeneity from CTCs detected in peripheral blood patient (pt) samples is a potential strategy to address this gap in knowledge. However, existing technology is generally limited to the capture and enumeration of CTCs, without a high-throughput method to quantify phenotypic properties. Here, we evaluated a novel nanotechnology platform – nanoparticle-mediated magnetic ranking cytometry (MagRC) to profile SCLC CTCs by EpCAM protein expression. Methods: Blood samples from 20 SCLC pts were processed through the MagRC platform. Magnetic nanoparticles conjugated with anti-EpCAM antibodies were incubated with whole blood samples then introduced into the MagRC device where CTCs are sorted by differently sized nickel micromagnets within microfluidic channels. Captured CTCs are ranked into 8 zones that correlate with EpCAM expression levels (zone 1 = highest to 8 = lowest). For 8 pts, all samples were processed at a 1mL/hr flow rate (fr), and for 12 pts, a 0.5mL/hr fr was also studied; 66% of all chips were processed at a 1ml/hr fr and 34% at a 0.5ml/hr fr. The average zone for each chip was compared to the flow rate, age, and stage (extensive-stage (ES) vs limited-stage (LS)). The differences were tested using the Wald test within the linear mixed effects model. Results: Among 20 pts, 11 were ES; 9 were LS. Median age at diagnosis was 69 years old (yo); 65% were male. We detected CTCs in 12 of 20 pts (60%), similar to other studies. When comparing the MagRC-ranked EpCAM zone, the 0.5mL/hr fr demonstrated a lower median zone (4.3 vs 6.5; p < 0.001) as compared to the 1mL/hr rate. Interestingly, pts > 65 yo had a higher median zone (6.2 vs. 3.5; p = 0.019) compared to those ≤65 yo. The effect remained significant after controlling for flow rate (p = 0.002). No EpCAM zone difference was detected between ES and LS. Conclusions: We demonstrate the ability of MagRC to quantify EpCAM expression levels of CTCs from SCLC pts. We observed a higher MagRC zone (i.e. lower EpCAM expression) from pts > 65 yo. This observation requires validation in larger datasets along with continued investigation into the biology of SCLC CTCs.

Cuticular structure of three Bunonema species and first description of the male of B. penardi Stefanski, 1914 (Nematoda: Bunonematidae)

This study reanalyses some morphological and ultrastructural aspects of three Bunonema species. Specimens of B. penardi, B. hessi and B. franzi were studied using light microscopy and SEM. Bunonema franzi was also studied by TEM. The male of B. penardi is described, this being the first record of males in the genus Bunonema. Additional morphometric data on the females of this species are presented. SEM pictures show details of the deviant amphid position within the Bunonematidae. In contrast to earlier reports, our TEM results show that the evagination of the cuticle in ridges and tubercles is due to the thickening of the median zone of the cuticle. Ultrastructural details of the species-specific polygonal mesh network on the right body side are revealed. The rods that constitute this network lie above the epicuticle and are therefore extracuticular.

Architecture et stratégies adaptatives des rejets de recépage du Buddleia variabilis

Cutting down close the stalks of Buddleia in February has resulted in an immediate development of populations of offshoots. Most of them would flower before the year was out. All of them, even those that remained vegetative, branched out and the branching showed mesotonous dominance. This was expressed, in the median zone, as a more pronounced increase in length of only one of the two branches at each node (stronger branch) rather than as an increase in leaf production. Reproductive branches are strong energy consumers; actually, they combine r strategy (seed production) with K strategy (pronounced cauline growth for space occupancy). Vegetative branches, weak energy consumers on which, however, leaves are particularly abundant, might serve as suppliers of metabolites. A nutritional equilibrium is perhaps achieved in a similar manner at the level of the stumps by the division of physiological roles between vegetative and reproductive offshoots. [Journal translation]

Étude biométrique du développement des folioles de Parkinsonia aculeata (Leguminosae)

There are three successive phases to foliolar development in Parkinsonia aculeata: (i) an initial phase during which primordium formation occurs; (ii) a morphogenic phase, with foliole formation; (iii) a histogenic and differentiation phase, with foliole development. Foliolar shape is determined during the basic morphogenic phase; a longer phase in which a zoning effect analogous to that seen in branches has been observed: (i) a zone of distal organ formation where folioles appear in constant succession, in a specific location, and in close proximity of each other along each border (these are the three criteria which define intrafoliolar generation centres); (ii) a histogenic median zone; and if the foliole is old enough (iii) a subproximal differentiation zone; (iv) an adult proximal zone.

Ultrastructural studies on the cuticle of the second-stage larvae of four root-knot nematodes: Meloidogyne hapla, M. javanica, M. incognita, and M. arenaria

Ultrastructural studies on the cuticle of the second-stage larvae of Meloidogyne hapla, M. javanica, M. incognita, and M. arenaria showed that the cuticle structure in all four species was similar and consisted of six layers divisible into three zones: an outer trilaminate cortex, a two-layered median zone, and a basal striated zone. No association could be established between the structure of the cuticle of L2 M. hapla and the ability of the nematode to survive freezing temperatures significantly better than L2 M. incognita.

The ultrastructure of the cuticle of the nematode Syphacia obvelata (Rudolphi, 1802). II. Modifications of the cuticle in the head end

The head region of the pinworm Syphacia obvelata (Rudolphi, 1802) has been examined to determine the nature of modification of the cuticle responsible for, or associated with, lips and buccal capsule, cephalic papillae and amphids, cephalic inflations, and cervical alae. The median zone of the cuticle was found to be the most modified and variation in the extent and distribution of striated material is compatible with its proposed structural role. The variations found are probably related to compensation for stresses that may develop in the cuticle during the complex movements of the head end. Lips are only inconspicuous expansions of the body wall cuticle, while esophageal cuticle is strikingly different in appearance. It is proposed to refer to all regions of the mouth cavity bounded by both the lips and esophagus as the buccal capsule while only the limited region bounded by body wall cuticle may be referred to as stoma. A mechanism involving three groups of intrahypodermal cytoskeletal filaments attached to the tips of somatic muscles, esophagus, and cuticle is proposed to move the lips.

The ultrastructure of the cuticle of the nematode Syphacia obvelata (Rudolphi, 1802). I. The body cuticle of larvae, males,and females, and observations on its development

The body cuticle of Syphacia obvelata (Rudolphi, 1802) has been examined with light and electron microscopy through larval and adult stages. In all stages the cuticle consists of a cortex, and median and basal zones. Material showing transverse striations with 180–220 Å periodicity (striated material) occurs in the median zone of larvae and young adults. However, progressive growth and deposition of more striated material results in the cuticle of older females appearing markedly different from the cuticle of the short-lived males. Striated material is concluded to be formed of bands of approximately circular discs. Overlap of such bands produces the various patterns seen in sections. Similarities between methods of formation of striated material and other cuticular components are noted between molting periods and the growth phase of females. The presence of intracuticular tubules and external longitudinal ridges is noted.

Basidiocarp development in Calocera cornea

The development of the basidiocarp of Calocera cornea in the natural and cultural environments is described. The structural unit is a narrow, unmodified hypha with the capacity for pigment and gel formation. In the basidiocarp the hyphae become organized into a central zone of compact, parallel hyphae, a median zone of interwoven hyphae with numerous spaces containing gelatinous material, and an outer zone composed of bifurcate basidia each bearing two basidiospores.Primordia and basidiocarps show rapid growth with marked sensitivity to relative humidity and sporulation frequently takes place before basidiocarp development is complete. Short periods of rapid growth alternate with long periods of inactivity during which the formation of fungal gel and carotenoid pigments probably aids in survival.

Metamorphic framework and plutonic styles in the Prince Rupert region of the Central Coast Mountains, British Columbia

The metamorphic framework in Prince Rupert – Skeena region of the Coast Mountains of British Columbia comprises schist, gneiss, and migmatite displaying progressive regional metamorphism that overlaps the Barrovian and Idahoan Facies Series. Although part of the circum-Pacific metamorphic zone, the Coast Mountain metamorphic belt is apparently not paired. Plutonic rocks, which were probably an integral part of the early metamorphic framework, have apparently been mobilized during metamorphism and continued to move out of their original environment while metamorphism waned, some even deforming the pre-existing fabric.Within the framework, four main plutonic styles have been recognized:1) Autochthonous, migmatitic, plutonic complexes.2) Para-autochthonous, steep-walled (tadpole) plutons.3) Para-autochthonous, tongue-shaped, recumbent plutons.4) Allochthonous, intrusive plutons.Quartz diorite and granodiorite are the most common plutonic rocks. Diorite and quartz monzonite are less common: gabbro and especially granite are rare.In the course of moving from the sites of generation to the zones of emplacement, the plutonic rock became:1) more homogeneous.2) less migmatitic and impoverished in inclusions.3) less foliated.4) more acidic, more biotite-rich.5) a rock containing plagioclase of lower average anorthite content and more complex oscillatory zoned crystals.The complex oscillatory zoning appears in a gross way to reflect the variable history accompanying (pulsative ?) movement during crystallization.Time of emplacement of most of the plutonic rock is not known. The potassium–argon age dates (between 53° N and 55° N) display a consistent pattern, with a westerly zone yielding the oldest dates (84 to 140 m.y.), a median zone, intermediate dates (64 to 79 m.y.) and the eastern zone, youngest dates (chiefly 40 to 50 m.y.). These dates may reflect sequential emplacement from west to east but some evidence also suggests that they may reflect sequential uplift and unroofing from west to east.