The concept of superposed fracture networks consisting of different generations, and often types, of fractures that have developed sequentially is discussed. Superposed networks can consist of different types of extension or shear fractures, and each fracture may abut, cross or follow (reactivate) earlier fractures. An example of a superposed fracture network in Liassic limestones in Somerset, UK, is presented, which comprises two sets of veins and a later joint network. The veins develop as damage zones around faults, with veins of the later set crossing or trailing along the earlier set. The later joints either cross-cut the earlier veins or reactivate them, the latter being common for the thicker (more than about 5 mm) veins. The veins and joint networks have markedly different geometries and topologies. The veins are spatially clustered and are typically dominated by I-nodes, while the joints are more evenly distributed and tend to be dominated by Y-nodes. The combined network of veins and joints at Lilstock is dominated by X-nodes because so many joints cross-cut the earlier veins. Understanding the development of superposed fracture networks leads to better understanding of the kinematic, mechanical, tectonic and fluid flow history of rocks.

This paper describes a vein-shaped graphite occurrence in which, for the first time, the geological, mineralogical and isotopic evidence support its formation by physical remobilization of previously formed syngenetic graphite. The deposit studied is located in the Spanish Central System and it occurs along the contact between a hydrothermal Ag-bearing quartz vein and a graphite-bearing quartzite layer. The characteristics of this occurrence differ from those of fluid-deposited vein-type graphite mineralization in that: (1) graphite flakes are oriented parallel to the vein walls; (2) graphite crystallinity is slightly lower than in the syngenetic precursor (graphite disseminated in the quartzite); and (3) the isotopic signatures of both types of graphite are identical and correspond to biogenic carbon. In addition, the P-T conditions of the hydrothermal Ag-bearing quartz veins in the study area (P <1 kbar, and T up to 360°C) contrast with the high degree of structural order of graphite in the vein. Therefore, physical remobilization of graphite can be regarded as a suitable alternative mechanism to account for some cases of vein-shaped graphite deposits. Such a mechanism would require a previous concentration of disseminated syngenetic graphite promoted, in this case, by the retrograde solubility of quartz. This process would generate monomineralic graphite aggregates enhancing its lubricant properties and permitting graphite to move in the solid state along distances in the range of up to several metres.

Diversity amongst the different populations is one of the problems in the control of medically important mosquitoes. Wing morphometry was used to identify within-species variation amongst some populations of Aedes aegypti in three areas of Lagos State, Nigeria. Ten landmarks on the right wing of adult female Ae. aegypti mosquitoes were digitized using TPSdig software. Relative distances of the veins and interpoints were calculated as well as the Euclidean distances based on these relative distances. In three (50%) of the interpoints, the relative distances were significant (P<0.05) to both the Brown–Forsythe F ratio and Welch ANOVA. The highest Euclidean distance of 7.738 was between Ebute Metta 2 and Badagry; the lowest of 4.426 was between Ikorodu and Ebute Metta 2. The distance between Ebute Metta 1 and Ebute Metta 2 was 5.867, which is more than the distance between Ebute Metta 2 and Ikorodu. Three groups of Ae. aegypti were identified, and the differences in lengths and interpoints observed on the wing veins suggest a possible morphological divergence amongst populations.

Platelet-activating factor (PAF) is a phospholipid with a wide range of biological activities. We studied PAF metabolism and PAF receptor (PAFR) signaling in perinatal ovine lungs to understand PAF's role in transition of the perinatal pulmonary hemodynamics and pathophysiology of persistent pulmonary hypertension of the newborn. We hypothesized that downregulation of PAF synthesis with upregulation of PAF catabolism by acetylhydrolase (PAF-Ah) in the newborn lung is needed for fetus-to-newborn pulmonary adaptation. Studies were conducted on fetal and newborn lamb pulmonary arteries (PA), veins (PV) and smooth muscle cells (SMC). PAF metabolism, PAFR binding and cell proliferation were studied by cell culture; gene expression was studied by qPCR. Fetal lungs synthesized 60% more PAF than newborn lungs. Compared with the fetal PVs and SMCs, PAF-Ah activity in newborn was 40–60% greater. PAF-Ah mRNA expression in newborn vessels was different from the expression by fetal PA. PAF-Ah gene clone activity confirmed deletion of hypoxia-sensitive site. PAFR mRNA expression by the PVs and SMC-PV of the fetus and newborn was greater than by corresponding PAs and SMC-PA. Q-PCR study of PAFR expression by the SMC-PV of both groups was greater than SMC-PA. Fetal SMCs bound more PAF than the newborn SMCs. PAFR antagonist, CV-3988, inhibited PAFR binding and DNA synthesis by the fetal SMCs, but augmented binding and DNA synthesis by newborn cells. We show different PAF–PAFR mediated effects in perinatal lungs, suggesting both transcriptional and translational regulation of PAF-Ah and PAFR expression in the perinatal lamb lungs. These indicate that the downregulation of PAF-mediated effects postnatally protects against persistent pulmonary hypertension of the newborn.

Numerous Variscan syntectonic calcite veins cross-cut Palaeozoic rocks in the Moravian Karst. A structural, petrographic and stable isotopic analysis of the calcite veins and a microthermometric study of fluid inclusions in these vein cements have been carried out to determine the origin of the Variscan fluids and their migration during burial and deformation. The isotopic parameters of white (older, more deformed) and rose (younger) calcites are: 87Sr/86Sr is between 0.7078 and 0.7082 (white) and 0.7086 (rose), δ18O is between +17.7 and +26.1 (white) and between +14.8 and +20.7 ‰ SMOW (rose), δ13C ranges from +0.1 to +2.5 (white) and from −0.3 to +1.6 ‰ V-PDB (rose). The isotopic signatures point to precipitation in an older fluid system buffered by the host rock (white calcites) and to an open, younger fluid-dominated system (rose calcites). Parent fluids (H2O–NaCl system) had salinities between 0.35 and 17.25 eq. wt % NaCl. The pressure-corrected and confined homogenization temperatures suggest formation of the calcite veins from a fluid with a temperature between 120 and 170 °C, a pressure of 300–880 bar at a depth between 2.1 and 3.2 km. The fluids were most likely confined to a particular sedimentary bed as a bed-scale fluid migration (white older calcite veins) or, later, to a pile of Palaeozoic sediments as a stratigraphically restricted fluid flow (rose younger calcite veins). The low temperatures and pressures during precipitation of calcites, which took place close to a peak of burial/deformation, confirm the distal position of the Moravian Karst region within the Variscan orogen.

To elucidate if an effect of propofol on endothelium-dependent relaxation could contribute to propofol-induced vasodilation, smooth muscle relaxation of isolated human omental artery and vein segments precontracted by endothelin-1 were measured. Substance P induced a concentration-dependent relaxation (mean ±SEM) in both artery (63 ± 8.4% of precontraction, n=9) and vein (60 ± 11%, n=7). The relaxation was enhanced by 10−6 M propofol (artery, 72 a 9.5%, n=9; vein, 81 ± 12%, n=7) but not affected by 10−7, 10−5 and 10−4 M propofol. In the presence of Nω-nitro-L-arginine methyl ester (nitric oxide synthase inhibitor), 10−6 M propofol still enhanced the substance P-induced relaxation in arteries but not veins, whereas 10−4 M propofol inhibited the relaxation in both arteries (rightward shift of the concentration-response curve) and veins (28 ± 7.5%, n=8). In the presence of potassium chloride (to prevent hyperpolarization), the enhancement of substance P-induced relaxation by 10−6 M propofol was abolished in both arteries and veins whereas 10−5 and 10−4 M propofol reduced the relaxation in arteries (38 ± 13% at 10−5 M, n=6; 30 ± 11% at 10−4 M, n=6) but not in veins. These results demonstrate that propofol, at lower, clinically relevant concentrations, promotes endothelium-dependent relaxation mediated via hyperpolarization in human omental arteries and via both nitric oxide and hyperpolarization in human omental veins.

Lemierre’s syndrome is a recognized but infrequently seen complication of acute oropharyngitis. In this case report the patient presented with acute sore throat that led to a bacteraemia with internal jugular vein thrombosis and subsequent cranial nerve palsies.