Layered Strata Research Articles

Cytoarchitecture and cortical connections of the anterior cingulate and adjacent somatomotor fields in the rhesus monkey

The cytoarchitecture and cortical connections of the anterior cingulate, medial and dorsal premotor, and precentral region are investigated using the Nissl and NeuN staining methods and the fluorescent retrograde tract tracing technique. There is a gradual stepwise laminar change in the cytoarchitectonic organization from the proisocortical anterior cingulate region, through the lower and upper banks of the cingulate sulcus, to the dorsolateral isocortical premotor and precentral motor regions of the frontal lobe. These changes are characterized by a gradational emphasis on the lower stratum layers (V and VI) in the proisocortical cingulate region to the upper stratum layers (II and III) in the premotor and precentral motor region. This is accompanied by a progressive widening of layers III and VI, a poorly delineated border between layers III and V and a sequential increase in the size of layer V neurons culminating in the presence of giant Betz cells in the precentral motor region. The overall patterns of corticocortical connections paralleled the sequential changes in cytoarchitectonic organization. The proisocortical areas have connections with cingulate motor, supplementary motor, premotor and precentral motor areas on the one hand and have widespread connections with the frontal, parietal, temporal and multimodal association cortex and limbic regions on the other. The dorsal premotor areas have connections with the proisocortical areas including cingulate motor areas and supplementary motor area on the one hand, and premotor and precentral motor cortex on the other. Additionally, this region has significant connections with posterior parietal cortex and limited connections with prefrontal, limbic and multimodal regions. The precentral motor cortex also has connections with the proisocortical areas and premotor areas. Its other connections are limited to the somatosensory regions of the parietal lobe. Since the isocortical motor areas on the dorsal convexity mediate voluntary motor function, their close connectional relationship with the cingulate areas form a pivotal limbic-motor interface that could provide critical sources of cognitive, emotional and motivational influence on complex motor function.

Altered microRNA expression associated with chromosomal changes contributes to cervical carcinogenesis

Little is known about the alterations in microRNA (miRNA) expression patterns during the consecutive stages of cervical cancer development and their association with chromosomal instability. In this study, miRNA expression in normal cervical squamous epithelium, high-grade precancerous lesions (cervical intraepithelial neoplasia (CIN2-3)), squamous cell carcinomas (SCCs) and adenocarcinomas (AdCAs) was integrated with previously generated chromosomal profiles of the same samples. Significantly differential expression during the consecutive stages of cervical SCC development was observed for 106 miRNAs. Of these differentially expressed miRNAs, 27 showed early transiently altered expression in CIN2-3 lesions only, 46 miRNAs showed late altered expression in SCCs only and 33 showed continuously altered expression in both CIN2-3 and SCCs. Altered expression of five significantly differentially expressed miRNAs, hsa-miR-9 (1q23.2), hsa-miR-15b (3q25.32), hsa-miR-28-5p (3q27.3), hsa-miR-100 and hsa-miR-125b (both 11q24.1), was directly linked to frequent chromosomal alterations. Functional analyses were performed for hsa-miR-9, representing a potential oncogene with increased expression linked to a chromosomal gain of 1q. Hsa-miR-9 overexpression was found to increase cell viability, anchorage-independent growth and migration in vitro. Upon organic raft culturing, hsa-miR-9 hampered differentiation and induced proliferation in all strata of the epithelial layer. These findings support a potential oncogenic function of hsa-miR-9 in cervical cancer. In summary, differential expression of 106 miRNAs, partly associated with chromosomal alterations, was observed during cervical SCC development. Altered expression of hsa-miR-9 associated with a chromosomal gain of chromosome 1q was shown to be functionally relevant, underlining the importance of deregulated miRNA expression in cervical carcinogenesis.

QG2井熔结火山碎屑岩锆石定年及其地质意义<br>U-Pb Zircon Dating of the Mesozoic Welded Pyroclastics in the QG2 Well and Its Geological Significance

辽河坳陷西部凹陷齐家潜山的Qg2井钻遇一套含油性较好的火山岩，通过岩石学和地球化学特征研究，认为是一套典型的壳源酸性钙性岩类，确定为爆发相的熔结角砾凝灰岩。该套火山岩形成时代和地层归属一直存在较大分歧，当时根据区域资料将其归为中生界早白垩纪义县组，但缺乏精确的年代学证据。为了进一步确定该套火山岩的形成时代和地层层位，笔者先是利用LA-ICP-MS锆石原位U-Pb定年方法，获得了熔结角砾凝灰岩的喷发年龄为168.9 ± 1.1 Ma，喷发时代为中生代中侏罗世，与辽西建昌盆地、河北承德盆地以及北京西山马兰村的的髫髻山组的火山岩在形成时代和岩性特征上具有可比性，因此，该套火山岩地层层位确定为髫髻山组，修正了以往对该套火山岩地层归属的观点，为下一步研究该类火山岩油气藏的空间展布奠定了基础。 The QG2 Well drilled into a suite of volcanic rocks with good oil-bearing property, which is located in Qijia buried hill, the western sag of Xialiaohe Concave. According to the results of petrography and geochemistry, this suite of volcanic rocks is identified as a suit of classical acid calcareous rock of crust source type, a lava tuff breccia with explosive faces. However, there has been a long debate on the formation age and stratum layer of this suite of volcanic rocks. Based on the regional geological data, it is previously classified into Yixian Formation of Early Cretaceous, but lack of precise chronological evidence. In order to accurately determine its formation age and stratum layer, we performed LA-ICP-MS. Our results indicated that this suite of volcanic rocks was formed at 168.9 ± 1.1 Ma in the period of Middle Jurassic, which is comparable to Tiaojishan Formation in Jianchang Basin of Western Liaoning Province, Chende Basin of Hebei Province, Malan Village of Western Hills of Beijing. So its stratum was defined as Tiaojishan Formation. The result revised the stratigraphical division of this suite of volcanic rocks. This opens the door for further study the distribution of oil and gas in this type of volcanic rocks.

Self-Standing Polyelectrolyte Multilayer Films Based on Light-Triggered Disassembly of a Sacrificial Layer

In the present article, we present a new and convenient optical method for the preparation of self-standing polyelectrolyte multilayer films. This method employs the disassembly of a sacrificial layer stratum composed of five poly(acrylate, merocyanine) PMC/poly(diallyldimethylammonium chloride) PDADMAC bilayers, which is triggered by the irradiation with visible light. This leads to the conversion of the zwitterionic PMC to its neutral isomer poly(acrylate, spiropyran) PSP, whereby the attractive ionic interactions between the neighboring bilayers vanish. The disassembly of the sacrificial layers in deionized water was completed within 47 s, when in-situ monitored at the maximum absorbance of PSP (λ = 360 nm), employing UV/visible spectrometry. Surprisingly, the disassembly duration of the sacrificial layers increased very little with an upper target film composed of 75 PDADMAC/PSS bilayers. The quick release of a thick target film (d ∼ 232 nm) composed of 100 (PDADMAC)/(PSS) bilayers in a large scale (7 × 18 mm(2)) could be ascribed not only to the vanished electrostatic attractive interaction between the layer pairs but also to increased hydrophobicity of the sacrificial layer element due to the photoisomerization of zwitterionic ionic PMC to neutral PSP. The unique advantages of this method as compared to the conventional approaches are demonstrated with the fast release (~2 min) of self-standing film combined with a well-defined, thin sacrificial layer (d ~ 30 nm). Moreover, harsh release conditions are also avoided, which significantly broadens the choice of materials that can be incorporated into the free-standing film.

An Accurate Method of Computing the Gradient of Seismic Wave Reflection Coefficients (SWRCs) for the Inversion of Stratum Parameters

The optimization inversion method based on derivatives is an important inversion technique in seismic data processing, where the key problem is how to compute the Jacobian matrix. The computational precision of the Jacobian matrix directly influences the success of the optimization inversion method. Currently, most of the AVO (amplitude versus offset) inversions are based on approximate expressions for the Zoeppritz equations to obtain the derivatives of the seismic wave reflection coefficients (SWRCs) with respect to the stratum parameters. As a result, the computational precision and range of applications of these AVO inversions are restricted undesirably. In order to improve the computational precision and to extend the range of applications of AVO inversions, the partial derivative equations of the Zoeppritz equations are established, with respect to the ratios of wave velocities and medium densities. By solving the partial derivative equations of the Zoeppritz equations accurately, we obtained the partial derivative of SWRCs with respect to the ratios of seismic wave velocities and medium densities. With the help of the chain rule for derivatives, the gradient of the SWRCs can be accurately computed. To better understand the behavior of the gradient of the SWRCs, we plotted the partial derivative curves of the SWRCs, analyzed the characteristics of these curves, and gained some new insight into the derivatives. Because only a linear system of equations is solved in our method without adding any new restrictions, the new computational method has both high precision and a quick running speed; it is not only suitable for small incident angles and weak reflection seismic waves but also for large incident angles and strong reflection seismic waves. With the theoretical foundations established in the article, we can further study inversion problems for layered stratum structures and we can further improve the computational speed and precision of the inversions.

Study on the Stability of Reservoir Landslide under Multiple-Factors Action

According to the survey and study on geological condition, the genetic mechanism and evolving process of the reservoir landslide were analyzed at first that the landslide experienced two large slides. The first slide occurred in the J2S2 formation, it's a collapse slide with small thickness sliding mass, but made the slope on the back edge of the landslide became steeper, which created the conditions for the second slide. The second slide mainly occurred in the J2S1 formation, it's a slide that cut layer of rock stratum, which formed present landside. Then, the influencing factors on the stability of reservoir landslide were analyzed, and finite element models were created to calculate and analyze the stability of reservoir landslide under multiple-factors action. The results shows that the landslide is stable in natural conditions, and the safety factor of landslide decreases after the normal storage of reservoir, which doesn't meet the specification requirements; when considering the sudden drop in reservoir level, rainfall infiltration and other factors, the safety factor of landslide decreases further, reaching the critical stable state, and landslides may be unstable when considering earthquake. Therefore, cutting slope and reducing load were suggested, and the calculations show that the landslide trends toward stable under action of multiple-factors after treatment, which means the research achievement has a great reference value to guide engineering design and construction.

Esophageal Epithelial ASIC3 is Associated With Increase in Severity of Symptoms in Patients With Gastro-Esophageal Reflux Disease (GERD)

Introduction Immunoreactive nerves and epithelial markers have been studied in the context of acid induced oesophageal hypersensitivity. Increase in immunoreactive TRPV1 nerves are associated with presence of oesophagitis12 as well as acid exposure time.3 ASIC3 was identified in epithelium of rat oesophagus and ASIC inhibitor (Amitidine) prevented oesophageal hyperaemic response in rats to CO2 infusion (mimicking acid).4 We aim to identify ASIC 3 in human oesophageal epithelium and to determine if it is a suitable biomarker of symptom severity in patients with gastro-oesophageal reflux disease (GORD). Methods 36 oesophageal mucosal biopsy samples from patients (age 19–59 years and 17 females) with or without GORD undergoing gastroscopy were obtained and their clinical symptoms were assessed using visual analogue scale (VAS) adapted from validated questionnaire ReQUEST. The symptoms assessed were; general feeling, acid complaints, upper abdominal complaints, lower abdominal complaints, nausea, sleep disturbances. Samples were paraffin fixed and analysed using immunohistochemistry for PGP 9.5 and ASIC3. Results Epithelial ASIC3 was identified in the mucosal biopsies (14 controls, 18 non-erosive reflux disease, 4 erosive oesophagitis). ASIC3 could be classified based on distribution and morphology into 4 groups; basal layer (stratum basale), stratum spinosum perinuclear, stratum spinosum membrane bound and superficial luminal layer staining. Patients who scored higher on VAS for all 6 symptoms also demonstrated higher expression of all 4 ASIC3 features studied (median 65% (35–87) vs 57% (34–79), p=0.018). In particular, for acid complaints, sleep disturbance and lower GI complaints, this association was more significant (median 64% (46–81) vs 54% (38–69), p=0.002). Nerve fibres as stained by PGP 9.5 in human oesophageal epithelium were absent. Conclusion Presence of specific epithelial ASIC3 features in oesophageal epithelium was associated with increase in severity of common GORD symptoms. Further quantitative studies are required to study correlation of ASIC3 as an objective biomarker of symptom severity.

Variability in the Muscle Composition (Skeletal vs Smooth) of Rat Esophagus: Implication for the Mechanism of Vagally Mediated Lower Esophageal Sphincter Relaxation

G A A b st ra ct s in human esophageal epithelium as detected by PGP9.5 was absent.Epithelial ASIC3 was identified in all mucosal biopsies (14 controls, 18 non-erosive reflux disease, 4 erosive esophagitis). ASIC3 could be classified based on distribution and characteristic sub-cellular morphology into 4 groups; basal layer (stratum basale), stratum spinosum perinuclear, stratum spinosum membrane-bound, and superficial luminal layer staining. Patients with higher VAS symptom scores had greater expression of all 4 ASIC3 features studied (p= 0.018) with strongest associations between acid complaints and sleep disturbance (p=0.002). Conclusions: Presence of specific epithelial ASIC3 morphological features in esophageal epithelium was associated with increase in severity of common GERD symptoms.

Courtship, Mating and Agonistic Behaviour inPisaura mirabilis(Clerck, 1757)*

After a short review of the literature, beginning with the discovery of the nuptial gift of the nursery-web spider Pisaura mirabilis (Clerck, 1757) in 1884 by Van Hasselt, the courtship, mating, agonistic behaviour, and peaceful coexistence of a female with two males in a planted terrarium are described (Table 1). Details of the normal mating process with a wrapped fly of different sizes are given (Figs. 3–10). Copulations occurred during both day and night. Eyesight seems to be of little importance for recognition of sexes and the gift, apart from perceiving movements. Mating variations using a freshly caught unwrapped fly (Lucilia) (Figs. 11–12), a small fly (one Drosophila), a wrapped substitute (heather blossom, Fig. 13) and even without any gift (Figs. 14–15, 23) are shown (Table 4). Males can even perform successfully with females with prey or egg sacs and on nursery webs. Agonistic behaviour, gift robbery, disturbance of mating by a rival, a threesome with one female and two males, but also peaceful male-male encounters are described and illustrated (Figs. 16–23, Table 3). Intersexual aggression and sexual cannibalism are demonstrated and discussed. The so-called “feigning death” of males (Fig. 8) is considered as an evolutionarily stable trick of the male to maintain contact with the female within the dense layer of the herbaceous stratum if she suddenly runs away after a disturbance, or simply for recovering the gift. This behaviour also occurs when two males share one gift (Fig. 22) and try to copulate with each other (Fig. 19). The benefits and disadvantages of the different kinds of gifts, evolution of the gift, its functions and the degree of cannibalism are discussed. Comparisons with the mating behaviour of related Pisauridae and Trechaleidae species using gifts and silk in courtship are made, and suggestions for further research are given.

Method of processing data to test for underground water inflow in layered strata using simulation and analytical solutions

This article is concerned with processing of data in testing for groundwater inflow at the Imeretinsky lowland, the area where construction of the Olympic infrastructure for Sochi-2014 is planned. Under the complex hydrogeological conditions of this territory caused by the layered (anisotropic) structure of the stratum and a free-flow filtration regime, interpretation of pumping tests from imperfect wells gives rise to some difficulties related to the ambiguousness of identification of an analytical model. For interpretation, an entire spectrum of methods, including hydrodynamic modeling and analytical calculation, were used.

Immunohistochemical Analysis of Inducible and Endothelial Forms of Nitric Oxide Synthase in Cyclosporin A‐Induced Gingival Overgrowth

The contribution of nitric oxide (NO) to immune response and matrix degradation in the periodontal environment suggests a role for NO and NO-synthase (NOS) activity in the pathogenesis of cyclosporin A (CsA)-induced gingival overgrowth (GO). However, current knowledge on this topic is limited to experimental animal studies. The present study was undertaken on the basis of a hypothesis whether altered nitrite/nitrate levels in gingival crevicular fluid (GCF) and endothelial NOS (eNOS) and inducible NOS (iNOS) immunoreactivity in gingiva of CsA-treated patients contribute to the pathogenesis of CsA-induced GO. Twenty-four CsA-medicated renal transplant patients with GO (GO+; n = 12) or without GO (GO-; n = 12), 10 gingivitis, and 10 healthy subjects were included in the study. GCF samples from two proximal sites facing interdental papilla were collected, and papilla was excised. iNOS and eNOS were determined by immunohistochemistry. GCF nitrite/nitrate levels were analyzed based on the Griess reaction. Weak iNOS immunostaining was observed in the healthy and GO- groups. In the gingivitis and GO+ groups, iNOS immunostaining significantly increased in connective tissue. Epithelial immunostaining of iNOS was localized to basal keratinocytes and the lower layer of stratum (str.) spinosum in the gingivitis group. In the GO+ group, iNOS immunostaining was differentially localized to keratinocytes of str. superficiale but considerably decreased in the str. basale. Weak eNOS immunostaining was found in the healthy and GO- groups, whereas higher immunostaining was observed in the gingivitis and GO+ groups. No intergroup differences were observed regarding nitrite/nitrate levels in GCF. CsA differentially upregulated iNOS, but not eNOS, in overgrown gingiva, which may play a pivotal role in the pathogenesis of CsA-induced GO.

Modelling carbon dioxide sequestration in layered strata

Motivated by the geological sequestration of carbon dioxide (CO2), we study the propagation of gravity currents in a porous medium bounded by a thin layer of much lower permeability. We formulate a model for drainage assuming that the fluid remains simply connected throughout. Using this model we examine the propagation of both two-dimensional and axisymmetric currents numerically. We find that for the fixed-flux situation solutions approach a steady state which is described analytically. The approach to this final solution depends on both the permeability contrast and thickness of the thin layer, and in many cases the current first overshoots before relaxing back to its ultimate steady state. Finally, we examine propagation along multiple thin, lower permeability layers as a reduced-order model of the plume of CO2 currently being injected at Sleipner in the North Sea.

Physiology and Morphology of Color-Opponent Ganglion Cells in a Retina Expressing a Dual Gradient of S and M Opsins

Most mammals are dichromats, having short-wavelength-sensitive (S) and middle-wavelength-sensitive (M) cones. Smaller terrestrial species commonly express a dual gradient in opsins, with M opsin concentrated superiorly and declining inferiorly, and vice-versa for S opsin. Some ganglion cells in these retinas combine S- and M-cone inputs antagonistically, but no direct evidence links this physiological opponency with morphology; nor is it known whether opponency varies with the opsin gradients. By recording from >3000 ganglion cells in guinea pig, we identified small numbers of color-opponent cells. Chromatic properties were characterized by responses to monochromatic spots and/or spots produced by mixtures of two primary lights. Superior retina contained cells with strong S+/M- and M+/S- opponency, whereas inferior retina contained cells with weak opponency. In superior retina, the opponent cells had well-balanced M and S weights, while in inferior retina the weights were unbalanced, with the M weights being much weaker. The M and S components of opponent cell receptive fields had approximately the same diameter. Opponent cells injected with Lucifer yellow restricted their dendrites to the ON stratum of the inner plexiform layer and provided sufficient membrane area (approximately 2.1 x 10(4) microm(2)) to collect approximately 3.9 x 10(3) bipolar synapses. Two bistratified cells studied were nonopponent. The apparent decline in S/M opponency from superior to inferior retina is consistent with the dual gradient and a model where photoreceptor signals in both superior and inferior retina are processed by the same postreceptoral circuitry.

Effects of Tip Location and Shielding on Piles in Consolidating Ground

Pile foundations located within consolidating ground are commonly subjected to negative skin friction (NSF) and failures of pile foundations related to dragload (compressive force) and downdrag (pile settlement) have been reported in the literature. This paper reports the results of four centrifuge model tests, which were undertaken to achieve two objectives: first, to investigate the response of a single pile subjected to NSF with different pile tip location with respect to the end-bearing stratum layer; and second, to study the behavior of floating piles subjected to NSF with and without shielding by sacrificing piles. In addition, three-dimensional numerical analyses of the centrifuge model tests were carried out with elastoplastic slip considered at the pile-soil interface. The measured maximum β value at unprotected single end-bearing and floating pile was similar and slightly smaller than 0.3. On the contrary, smaller β values of 0.1 and 0.2 were mobilized at the shielded center piles for pile spacings of 5.0 d and 6.0 d, respectively. The measured maximum dragload of the center pile in the group at 5.0 d and 6.0 d spacing was only 53% and 75% of the measured maximum dragload of an isolated single pile, respectively. Correspondingly, the measured downdrag of the center pile was reduced to about 57% and 80% of the isolated single pile. Based on the numerical analyses, it is revealed that sacrificing piles “hang up” the soil between the piles in the group and, thus, the vertical effective stress in the soil so reduced, as is the horizontal effective stress acting on the center pile. This “hang-up” effect reduces with an increase in pile spacing. For a given pile spacing, shielding effect on dragload is larger than that on downdrag.

Design on a new oil well test shock absorber under impact load

Continuous operation of test and measurement is a new operating technique in the petroleum exploitation, which combines perforation with test and measurement effectively. In order to measure the original pressure of stratum layer exactly and prevent testing instrument from being impaired or damaged, a suitable shock absorber is urgently necessary to research. Based on the attempt on the FEM analysis and experiment research, a new shock absorber is designed and discussed in this paper. 3D finite element model is established and simulated accurately by LS-DYNA, the effect and the dynamic character of the shock absorber impact by half sinusoidal pulse force under the main lobe frequency are discussed both on theoretics and experiment. It is shown that the new designed shock absorber system has good capability of shock absorption for the impact load.

A leucine‐rich repeat membrane protein, 5T4, is expressed by a subtype of granule cells with dendritic arbors in specific strata of the mouse olfactory bulb

Segregation of neuron-type-specific synaptic connections in different strata is a characteristic feature shared by the olfactory bulb (OB) and retina. In the mammalian OB, mitral cells form dendrodendritic synapses with granule cells (GCs) in the deep stratum of the external plexiform layer (EPL), whereas tufted cells form dendrodendritic synapses in the superficial stratum. In the search for membrane proteins with strata-specific expression patterns, we found that a leucine-rich repeat membrane protein (5T4 oncofetal trophoblast glycoprotein) was expressed selectively by a subset of superficial GCs. The somata of 5T4-positive GCs were localized in or near the mitral cell layer, and their apical dendrites ramified preferentially in the superficial stratum of the EPL, where tufted cell dendrites ramified. Strata-specific expression of 5T4 was found also in the retina: 5T4 was expressed selectively by rod-bipolar cells and a subset of amacrine cells whose dendrites ramified in a specific sublamina of the inner plexiform layer. During the perinatal and postnatal development of the OB, 5T4 expression paralleled in time the formation of dendrodendritic synapses in the EPL. Odor deprivation during the first postnatal month selectively reduced the thickness of the superficial stratum of the EPL and the number of 5T4-positive GCs. Because 5T4 is known to interact with actin cytoskeleton, these observations suggest that 5T4 is involved in the formation or maintenance of strata-specific dendritic ramification or synaptic connection of subsets of local interneurons.

MODIFICATION OF SITE RESPONSE IN PRESENCE OF LOCALISED SOFT LAYER

Experimental and numerical simulations are performed to evaluate the modification of ground response resulting from either the presence of soft layers or occurrence of partial liquefaction. Results from two densely instrumented dynamic centrifuge tests are presented to show the ambiguous role played by the presence of a soft layer. It was found that the lateral extent of the soft layer has significant influence on the overall response of the layered strata and any structure founded on it. The experimental observations are supported by simplified numerical analysis. The amplification or deamplification of the input motion is found to be a function of the ratio of the width of soft layer to the wave length. Based on the numerical analysis, a general function describing the site amplification is presented which may be used as a guide in seismic design of foundations in such layered strata.

UDEC simulation for the dynamic response of a rock slope subject to explosions

Gas wells penetrating longwall mining areas are prone to fail by shear and distortion due to vulnerability to ground movements caused by coal mining, especially when they pierce layered strata. This work explores the influence of topography on stability for shale gas wells piercing a longwall pillar after sequential removal of the flanking panels. We examine the magnitudes of shear offsets, longitudinal distortions, delamination, lateral and vertical strains along the vertical well trajectories through a longwall pillar and as a result of mining, and evaluate their impact upon the anticipated performance and stability of the wells. Results indicate that the presence of weak interfaces separating monolithic beds is a crucial factor that modulates wellbore instability. Contrast between benign relief and incised surface topography amplifies shear offsets for wells in the overburden by ~ 20–30%. Well distortions are largest close to the surface or hilltop for mining at shallow depths (100 m) and migrate downwards with an increase in panel depths reaching a maximum in the vicinity of the seam. Tensile failure is more likely to occur for gas wells penetrating the overburden with incised topography, especially for the case with a higher ratio of hill height to the thickness of overburden below the valley floor, with a largest delamination of 42 mm. Incised topography does not cause a significant change in magnitude for axial distortions along well trajectories (limited to ± 3 × 10− 3) but does elevate lateral strains over the horizontal case to different extents. For all topographic conditions, lateral shear offsets and various strains are largest for boreholes that cross the pillar closest to the panel rib and reduce monotonically towards the gateroad, where both the shear offsets and axial distortions reduce to about one-fifth (horizontal) and one-tenth (incised) of the maximum at 7.5 m inboard of the gateroad. Well deformations are most severe when mining is shallow < 100 m, then moderate when mining at an intermediate depth ~ 200 m, and then become large again as the seam deepens > 300 m. The spread in the distribution of strain magnitudes between the five horizontal trajectories through the pillar all converge when mining is deeper.

Histological structure of the skin of the Southern Crested Newt, Triturus karelinii (Salamandridae: Urodela)

The histological structure of the skin of the Southern Crested Newt, Triturus karelinii, from the active aquatic period has been studied by different staining methods. The species has two main layers: epidermis and dermis. The epidermal layer contains stratum germinativum and stratum corneum; the dermal layer stratum spongiosum and stratum compactum. The dermis has a connective tissue structure and contains large amounts of chromatophores and secretory glands. While the stratum compactum of the dermis contains collagen fibres, the basal laminae of the epidermal stratum germinativum cells, apical facies of the stratum corneum cells and the dermal ground substances contain glycosaminoglycan structures. By using computerized image processing software, the thickness of the epidermis and dermis has been measured and the amount of collagen fibres in terms of chosen point determined. We conclude that the extracellular matrix of the T. karelinii skin is largely comprised of two structurally distinct molecular components: collagen and glycosaminoglycans, but the amount of these components may be different in the water and land periods, depending upon the activity of these amphibians.

Reciprocal inhibition of the AMPA and NMDA components of excitatory postsynaptic potentials in field CA1 of the rat hippocampus in vitro

The mutual effects of components of excitatory postsynaptic potentials (EPSP) induced by activation of glutamate receptors sensitive to alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) and N-methyl-D-aspartate (NMDA) were studied on living slices of rat hippocampus. Evoked responses were recorded in the radial layer (stratum radialis) in field CA1 after stimulation of collateral-commissural fibers. The contribution of the NMDA component to the total EPSP was altered by extracellular application of solutions containing different concentrations of magnesium. At low magnesium concentrations, when both components made significant contributions to EPSP, inhibition of one of the components by application of antagonists of the appropriate receptors led to increases in the area of the other component. Thus, the total magnitude of pharmacologically isolated components were significantly greater than the control response (for example, at 0.1 mM magnesium, the sum of the components was 340 +/- 120% of the control two-component EPSP (p < 0.01; N = 6). These results suggest that in controls, the AMPA and NMDA components of EPSP inhibit each other. The mutual inhibition of components may be an important factor affecting the conductivity and plastic properties of central glutamatergic synaptic pathways.