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As mining and tunnelling projects advance to deeper areas, strainbursts occur more frequently. This failure mode is extremely dangerous, as the rock mass fails abruptly, releasing high amounts of energy. This poses a high risk to the life of workers and equipment used. For a robust strainburst risk assessment many factors have to be taken into account. Besides geological features, overburden, excavation method, etc., rocks' intrinsic proneness to strainburst plays a major role. Whether a rock tends to this failure behaviour depends strongly on the rocks' mechanical and structural characteristics at the grain-level, especially on its heterogeneity. The authors demonstrate this based on different rock-like sample sets, consisting of a very fine-grained fibreless ultra-high-performance concrete (UHPC) and a constant volumetric fraction of coarse aggregates. Thereby, the heterogeneity aspect was introduced by the different properties of the aggregates. A laboratory program was performed, taking into account uniaxial compression tests (including post-failure tests to evaluate the failure energy) and Acoustic Emission Testing (to monitor the cracking activity). The study underlines the high suitability of using Acoustic Emission Testing (AET) in strainburst risk assessment. In addition, the authors analyse empirical parameters commonly used to evaluate rocks' intrinsic proneness to strainburst, and give recommendations regarding their application. Overall, the study substantiates former research and emphasises the usefulness of petrographic information within strainburst risk analysis. It also sets the base for future research on real rock, which will hopefully lead to more specific recommendations for practitioners on how to include rocks' grain-scale characteristics in strainburst risk analysis. Highlights: Laboratory test program demonstrating the potential of including rocks structure at grain-scale in estimating rocks intrinsic proneness regarding strainburst. Stiffness and shape aspects at grain-scale have a great influence on the intrinsic proneness to strainburst of rocks. Acoustic Emission Testing in laboratory is highly suited for capturing the materials intrinsic proneness to strainbursting. Commonly used empirical parameters based on laboratory tests, which evaluate rocks intrinsic proneness regarding strainburst, have to be applied with caution. [ABSTRACT FROM AUTHOR]

The effect of joint overlap on the full failure behavior of a rock bridge in the shear-box test was numerically investigated by means of the particle flow code in two dimensions (PFC2D). Initially, the PFC2D was calibrated by use of data obtained from experimental laboratory tests to ensure the conformity of the simulated numerical model's response. Furthermore, validation of the simulated models was cross-checked with the results from direct shear tests performed on non-persistent jointed physical models. By use of numerical direct shear tests, the failure process was visually observed and the failure patterns were seen to be in reasonable accordance with experimental results. Discrete element simulations demonstrated that macro shear fractures in rock bridges are because of microscopic tensile breakage of a large number of bonded discs. The failure pattern is mostly affected by joint overlap whereas the shear strength is closely related to the failure pattern. The results show that non-overlapping joints lost their loading capacity when nearly 50 % of total cracks developed within the rock bridge whereas the overlapping joints lost their loading capacity as soon as cracks initiated from the joint walls. Furthermore, progressive failure or stable crack growth was seen to develop for non-overlapped joints whereas brittle failure or unstable crack growth was seen to develop in overlapped joints. [ABSTRACT FROM AUTHOR]

Particle flow code 2D (PFC2D) was adopted to simulate the shear behavior of rocklike material samples containing planar non-persistent joints. Direct shear loading was conducted to investigate the effect of joint separation on the failure behavior of rock bridges. Initially calibration of PFC was undertaken with respect to the data obtained from experimental laboratory tests to ensure the conformity of the simulated numerical models response. Furthermore, validation of the simulated models were cross checked with the results of direct shear tests performed on non-persistent jointed physical models. Through numerical direct shear tests, the failure process was visually observed, and the failure patterns were found reasonably similar to the experimentally observed trends. The discrete element simulations demonstrated that the macro-scale shear zone resulted from the progressive failure of the tension-induced micro-cracks. The failure pattern was mostly influenced by joint separation, while the shear strength was linked to the failure pattern and failure mechanism. Furthermore, it was observed that the failure zone is relatively narrow and has a symmetrical pattern when rock bridges occupy a low percentage of the total shear surface. This may be due to the high stress interactions between the subsequent joints separated by a rock bridge. In contrast, when rock bridges are occupying sufficient area prohibiting the stress interactions to occur then the rupture of surface is more complex and turns into a shear zone. This zone was observed to be relatively thick with an unsymmetrical pattern. The shear strength of rock bridges is reduced by increasing the joint length as a result of increasing both the stress concentration at tip of the joints and the stress interaction between the joints. [ABSTRACT FROM AUTHOR]

Given a family ofk+ 1 real-valued functionsdefined on the setand measuring theintensityof certain signals, we want to investigate whether these functions are ‘dependent’ or ‘independent’ by checking whether, for some given family of threshold valuesthe sizeaof the collection of numberswhose signalsexceed the corresponding threshold valuessimultaneously for allis surprisingly large (or small) in comparison to the family of cardinalitiesof those numberswhose signalsf i(j) individually exceed, for a given indexi, the corresponding threshold valueT i. Such problems turn presently up intopological proteomics, a new direction of protein-interaction research that has become feasible due to new techniques developed in fluorescence microscopy calledMulti-Epitope Ligand Cartography(or, for short, MELK = Multi-Epitop Liganden Kartographie). The above problem has led us to study the numbersof families of subsetsofwithfor allandand to investigate their asymptotic behaviour. In this note, we show that the associated probability distributionsdefined on the setof non-negative integers byconverge, withn? 8, towards thePoisson distributionfor some fixedprovided the numbersare assumed to converge withnto infinity in such a way that the conditionsare satisfied. Remarkably, it is the alternating signs in the expressions forresulting from the standard exclusion-inclusion principle that correspond to the alternating signs in the power series expression for exp(-a) whennturns to infinity. [ABSTRACT FROM AUTHOR]

Ultrafine tungsten carbide and fine cobalt as well as nano yttrium oxide powders were used as the raw materials. The effects of hot-press below the eutectic temperature and conventional liquid phase sintering on the structures and properties of WC-20Co-1Y2O3 cemented carbide were studied. It is shown that hot-pressed alloy has the character of isotropic properties and microstructure with homogeneous and ultrafine WC grains. However, the ultrafine and fully-densified structure is developed at the cost of the presence of large amount of cobalt-lake (unevenly distributed binder phase), and thus lower strength. Yttrium oxide in the alloy cannot play the role of grain growth inhibitor fully when cemented carbide with high content of cobalt and ultrafine raw materials is sintered at high liquid phase sintering temperature. Peculiar platelet-enhanced bi-model structure is formed in WC-20Co-1Y2O3 cemented carbide by conventional liquid phase sintering, which points out that yttrium oxide in the alloy facilitates the formation of plate-like WC grain. [ABSTRACT FROM AUTHOR]

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Through the use of a zonal balance model we investigate the properties of the tropical meridional circulation to a range of specified diabatic forcing fields for climatologically observed zonal winds. As in earlier studies, the solutions show that latent heat release away from the equator forces an asymmetric meridional circulation in response the anisotropy in the inertial stability parameter with respect to the meridional location of the forcing. The presence of strong zonal flows appears to play a relatively minor role in determining the magnitude and asymmetry of the meridional circulation, whereas the structure of the diabatic heating, particularly the meridional breadth, proves to be of much greater importance. A dynamic efficiency factor, which provides an analytic measure of the efficacy of diabatic heating at generating zonal kinetic energy, generally exhibits a meridionally symmetric structure except during Northern Hemisphere summer. This asymmetry gives rise to a pronounced sensitivity of zonal kinetic energy generation to the meridional location of ITCZ convection. Further examination of the flow pattern suggests that for zonal flows representative of those over the Indian Ocean during the Northern Hemisphere summer months, meridional displacements of the heating of less than 20° latitude can result in as much as an order of magnitude difference in the rate of kinetic energy generation. Solution of the balance system also implies the existence of a feedback mechanism, between zonally-organized convection and the energetics properties of the large-scale flow, that is highly sensitive to the meridional location of the convection. [ABSTRACT FROM AUTHOR]

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Lyell's syndrome (LS) (toxic epidermal necrolysis) is also known as 'scalded skin syndrome.' When caused by staphylococci, it has a favorable prognosis. However, as a drug reaction, primarily to sulfonamides, anticonvulsives, and antirheumatic agents, it often takes a fatal course. On the basis of a case report, the authors present a new therapeutic concept aimed at influencing the pathobiochemical changes underlying LS. After taking a single dose of a sulfonamide preparation for a mild urinary tract infection, a 14-year-old girl developed LS with skin changes covering almost the whole body surface. Within 12 h the child showed signs of sepsis with imminent organ failure, leuco- and thrombocytopenia, and symptoms of beginning enteroparalysis. Wholeblood chemiluminescence analyses revealed massive formation of reactive oxygen species. Parallel to this, a drastic increase in PMN-elastase and strong activation of the kallikrein-kinin system were found. Blood concentrations of glutathione peroxidase and reduced glutathione were extremely low. The therapeutic regimen was intended to prevent both endotoxinemia and overproduction of toxic oxygen metabolites: the girl received 100 μg monoclonal antibody against endotoxin (Centoxin) in combination with sodium selenite (Selenase). By day 2 her circulatory condition had stabilized and the blood concentration of oxygen radicals decreased. Neither liver nor kidney function showed pathological changes. Although on day 2 maximum activation of the kallikreinkinin system was observed, the expected drop in blood pressure did not occur. The blood concentration of elastate fell markedly, indicating that the release of elastase from neutrophil granulocytes, stimulated by endotoxin and complement, could be prevented. Both blood and plasma activities of glutathione peroxidase increased sharply as a consequence of the selenium therapy. On the 8th day of therapy all parameters had returned to normal (elastase, kallikrein-kinin, leucocytes, selenium). The whole-blood chemiliminescence response showed normal values and the skin changes had almost completely disappeared. [ABSTRACT FROM AUTHOR]

In-vivo photoacoustic spectra (PAS) of pure cultures of cyanobacteria and photosynthetic bacteria ( Chromatiaceae) which usually occur in stromatolitic microbial mats were measured. The PA spectra of the pure cultures were compared to PA spectra measured directly on different layers of microbial mats from Mellum (North Sea). The advantages of PAS of opaque, solid samples (e.g., sediment, rock), and of particle suspensions (e.g., light-scattering cell cultures with interference by sulfur globules) over conventional spectroscopy using classical in-vivo or extraction photometry are discussed. [ABSTRACT FROM AUTHOR]

The artificial implantable pancreas is seen as the optimal means of therapy in patients with severe diabetes mellitus. The implantable pancreas consists of three modules; (i) the dosing unit, (ii) the control circuit and (iii) a glucose sensor for the realisation of a feedback system. Intensive research has been devoted to essential items, such as a dosing valve with only minimal susceptibility to interference, the design of an electrochemical sensor for continuously monitoring the glucose leve!, and design criteria for data transfer between an external programmer/monitor and the implant. [ABSTRACT FROM AUTHOR]

A randomised, single-blind comparative study was carried out in 9 ovariectomized women to evaluate the kinetics of single doses of three different steroid combinations: 0.150 mg desogestrel +2.0 mg micronized 17β-oestradiol, 0.150 mg desogestrel +0.500 mg 17β-oestradiol cyclo-octyl acetate and 0.150 mg desogestrel +1.0 mg 17β-oestradiol decanoate. Serum levels of 17β-oestradiol and oestrone were measured, as well as the excretion of 17β-oestradiol and its metabolites (oestrone and oestriol) in urine. In relation to the doses given, higher peak serum concentrations of 17β-oestradiol were obtained after the two fat soluble analogues, while the AUCs were similar to that after micronised 17β-oestradiol. However, there was more extensive conversion of the micronised 17β-oestradiol preparation into oestrone compared to 17β-oestradiol cyclo-octyl acetate and 17β-oestradiol decanoate. The oestrone/17β-oestradiol serum concentration ratio was approximately 2.6 before tablet intake and remained essentially unchanged after intake of 17β-oestradiol cyclo-octyl acetate and 17β-oestradiol decanoate. After micronized 17β-oestradiol however, there was a 2-3-fold increase in the ratio at C and slower elimination of 17β-oestradiol from plasma, which may be due to the fact that high serum oestrone levels may serve as a reservoir, since both a metabolite and also a precursor of 17β-oestradiol. The urinary excretion of 17β-oestradiol, oestrone and oestriol was highest after oral administration of micronized 17β-oestradiol compared to 17β-oestradiol cyclo-octyl acetate and 17β-oestradiol decanoate. The time pattern of urinary excretion reflected the serum concentration profiles of the preparations given. [ABSTRACT FROM AUTHOR]

In fault zones, excessive deformation during and after tunnel excavation is frequently encountered. Shoterete in combination with grouted rock bolts has successfully been used in many applications to control the deformation process. The magnitude of deformation frequently exceeds the deformability of the shotcrete lining. In the past, this problem has been solved by dividing the shotcrete lining into 'segments' and leaving gaps between the segments to accommodate deformation without damage to the lining. The need for minimizing deformation in an extremely heterogeneous fault zone at the Galgenbergtunnel (Austria) led to the development of low cost yielding elements, installed between the shotcrete 'segments' and the use of a new type of re-groutable brock bolts. New techniques in evaluating the results of displacement monitoring have improved the short term prediction. [ABSTRACT FROM AUTHOR]

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Background: Lateral release (LR) is an integral part of surgical correction of hallux valgus. A comparison was made between the open and minimally invasive LR techniques using a dorsal approach. The reliability and safety of the two methods were compared. Besides, the release of specific structures was investigated with special emphasis on ascertaining if the release was partial or a total one., Methods: In this study on cadavers, LR was performed on nine pairs of foot and ankle specimens. The group assignments were randomized for each case. The operations were followed by anatomical preparation, data collection, photo documentation, and statistical analysis., Results: A statistically significant advantage was observed with the open dorsal approach as there was a complete release of the adductor hallucis muscle from the lateral sesamoid and the lateral metatarsosesamoid ligament ( p  = 0.015 in each case). In terms of releasing the adductor hallucis muscle from the proximal phalanx, the lateral joint capsule, and the lateral collateral ligament, none of the investigated procedures showed better performance. However, open dorsal access tends to show a higher degree of release more frequently., Conclusions: Splitting of the lateral joint capsule, including the lateral collateral ligament and lateral metatarsosesamoid ligament via the dorsal approach can be performed reliably and completely using the open surgical technique. The open dorsal technique shows better rates of detachment when the adductor hallucis muscle is released from the lateral sesamoid. Both techniques resulted in incomplete release of the adductor hallucis muscle from the proximal phalanx., Study Type: Therapeutic-investigating the results of a treatment., Level of Evidence: II (Prospective cohort study)., Supplementary Information: The online version contains supplementary material available at 10.1007/s43465-021-00575-3., Competing Interests: Conflict of InterestThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. ICMJE forms for all authors are available online., (© Indian Orthopaedics Association 2021.)