Ganoderma lucidum: A promising anti-inflammatory medicinal plant

Inflammation is a complex process and part of the host immune defense against invading micro-organism or trauma. Over production of some pro-inflammatory mediators can lead to chronic diseases of the inflammatory origin. Medicinal Plants which are used as anti-inflammatory agents, mainly act affecting various stages of the process of inflammation. In general they can inhibit formation of a wide of mediators such as cytokines by immune cells to prevent the inflammatory reaction cascade from starting. The use of most of the medicinal plants in treatment of chronic disease of the inflammatory origin is based on clinical and pharmacological trials. Meanwhile, the use of most of them is based on their longstanding traditional use in folk medicine. In this review, we report some of anti-inflammatory effects of G. lucidum as an ancient Chinese herbal medicine

Preventing failure of the anchoring system in underground coal mines

Cable bolts are commonly used as anchoring element in many underground mines. Reports on the premature failure of cable bolts in underground coal mines due to stress corrosion cracking (SCC) have been increasing in the past two decades. The previous studies found that the diffusion of atomic hydrogen into steel causes the SCC in cable bolts, which is known as hydrogen-induced stress corrosion cracking (HISCC). While the research on the mechanism of the HISCC in underground mines needs to be continued, it is essential to develop prevention measures to avoid such a failure. In this study, a variety of prevention measures that claim to prevent corrosion of steel were examined. Specifically, barrier coating, i.e., polymer, epoxy coating, as well as the sacrificial coating, i.e., hot-dip galvanising, methods were tested. Testing specimens were made by inserting loading pins between locked cable bolt king wires (coated) to simulate the in-situ stress condition. Cable bolt specimens were then fully immersed into a hydrogen sulphide solution to determine their resistance against HISCC. The test results showed that all the coatings had delayed the failure in varying degrees, but very few have significantly extended the time to fracturing. The polymer and epoxy coatings have become breached during the testing, and the failure occurred shortly after. The galvanised coating was dissolved in the testing solution and again allowed access of the solution to the steel surface, and subsequently resulted in failure. This indicates that these coatings can be potentially applied to prevent SCC failure; however, their impacts on the performance of bolts, such as their bonding with grout and bolt, still need to be considered

Stress corrosion cracking of cable bolts in tunnels: An in-situ testing approach

Premature failure of cable bolts in underground tunnels is a major concern for the mining and civil industries. The unexpected failure of cable bolts in tunnels can threaten the safety of excavation operations and cause subnational economic losses. In this study, an in-situ testing method was developed to identify the cause of failure in the environment where the cable bolts are installed. The testing was conducted in two underground mine tunnels in Australia. The coupon made from non-galvanised and galvanised cable bolt wires with multiple stressed sections were installed in the tunnel roof, allowing direct exposure of coupons to different rock strata environments. The coupons were retrieved from the tunnels after almost ten months and analysed for corrosion. Results from both tunnels showed the occurrence of stress corrosion cracking (SCC) in both non-galvanised and galvanised coupons. The cracking predominantly occurred in the sections exposed to claystone layers. The framework developed in this study can be applied to different regions of any underground spaces to assess the propensity of the environment to cause premature reinforcement failure

FracDetect: A novel algorithm for 3D fracture detection in digital fractured rocks

Fractures have a governing effect on the physical properties of fractured rocks, such as permeability. Accurate representation of 3D fractures is, therefore, required for precise analysis of digital fractured rocks. However, conventional segmentation methods fail to detect and label the fractures with aperture sizes near or below the resolution of 3D micro-computed tomographic (micro-CT) images, which are visible in the greyscale images, and where greyscale intensity convolution between different phases exists. In addition, conventional methods are highly subjective to user interpretation. Herein, a novel algorithm for the automatic detection of fractures from greyscale 3D micro-CT images is proposed. The algorithm involves a low-level early vision stage, which identifies potential fractures, followed by a high-level interpretative stage, which enforces planar continuity to reject false positives and more reliably extract planar fractures from digital rock images. A manually segmented fractured shale sample was used as the groundtruth, with which the efficacy of the algorithm in 3D fracture detection was validated. Following this, the proposed and conventional methods were applied to detect fractures in digital fractured coal and shale samples. Based on these analyses, the impact of fracture detection accuracy on the analysis of fractured rocks' physical properties was inferred

Microbiologically influenced stress corrosion cracking responsible for catastrophic failure of cable bolts

In the past two decades, reports of the premature failure of cable bolts used in the mining and civil industries have been increasing. Previous studies have established that failure occurs through hydrogen-induced stress corrosion cracking (HISCC), which is a type of environmentally assisted hydrogen cracking. However, to date, the cause of HISCC has been unclear. For the first time, we studied the role of microorganisms in the failure of cable bolts using components present in SCC-affected mines. Stressed coupons were prepared from the cable bolt wires and tested in groundwater with additions of sulphate-reducing bacteria, coal, clay, pyrite and lactate. It was found that hydrogen sulphide (H2S) produced by sulphate- and sulphur-reducing bacteria promoted hydrogen diffusion into the steel and, in the presence of stress, caused HISCC. This suggests that control of H2S production should be a priority for mining and civil industries to avoid premature failure of anchoring systems

Acute right heart failure in a patient with right heart thrombus and pulmonary thromboembolism

Right Heart Thrombus (RiHT) management is really controversial, and appropriate guidelines are not present for the management. In patients referring with RiHT and Pulmonary Embolism (PE), there are three ways of managing these patients. Out of the three one is thrombectomy which is with high risk taking in mind the comorbidities these patients have. The other is using thrombolytic which, in many cases is contraindicated or with high risk. The other less effective way is full anticoagulation. It is really controversial to choose between these ways of management and no clear approach is present. The case presented is a 44-year-old morbid obese male with history of dyspnea on exertion (functional Class II) and foot oedema or the last three months, who was transferred to the emergency department with respiratory distress and hypoxia. Echocardiography was done for the patient which showed moderate Right Ventricular (RV) dysfunction with severe RV enlargement and a severe Tricuspid Regurgitation (TR) with TR gradient of 70mmHg. He also had a semi-mobile large pedunculated mass in favour of a clot in his RV cavity. With the impression of PE heparin was administered to the patient and he was admitted in the coronary care unit. Pulmonary Computed Tomography (CT) angiography showed sub-segmental Pulmonary Thromboendarterectomy (PTE) in the left lung. He had negative cardiac markers and stable vital signs and so full anticoagulation was chosen for his treatment. His clinical course was uneventful and after 10 days of treatment the RV size and function improved significantly. On follow-up after a month he was doing well. Although recent Guidelines of European Society of Cardiology in management of acute PE stated that RiHT, particularly mobile, are associated with a significantly increased early mortality risk in patients with acute PE. Immediate therapy is mandatory, but optimal treatment is controversial in the absence of controlled trials. Thrombolysis and embolectomy are probably both effective while anticoagulation alone seems to be less effective. � 2016, Journal of Clinical and Diagnostic Research. All rights reserved

Digital and experimental rock analysis of proppant injection into naturally fractured coal

Proppant-laden fluid injection has been applied to many low permeability reservoirs, such as coal seams, to enhance permeability and thus production. While there are several laboratory-scale experimental studies on proppant placement in hydraulic fractures, the possible infiltration of proppant into natural fractures and its effect on overall permeability has received little attention. We study proppant injection into a naturally fractured coal sample by a combination of experimental and digital rock technologies. The sample was imaged using a helical X-ray computed tomography (micro-CT) scanner in as-received condition. Then, proppants of different size ranges were gradually injected into the sample, using a purpose-built X-ray transparent core flooding system, and the permeability was measured at different effective stresses. Subsequently, the propped sample was re-imaged and registered to the as-received image to map the internal changes. The experimental results indicated almost no permeability change of the sample after proppant injection. While proppant collection in the outlet proved passage of the proppant through the sample, observation of the sample indicated that some of the proppants were accumulated on the inlet face of the core and created a filter leading to no permeability increment. Micro-CT images confirmed that proppants were effectively placed in the sample and kept the fractures open. Numerical computation of permeability, using the digital coal sample in which accumulated proppants at the coal surface were excluded, indicated a significant increase in the sample permeability. Such an increase resulted from the opening of the fractures, particularly in the outlet region. This demonstrated the significance of proppant size selection for coal seam hydraulic fracturing. While proppants were successfully placed in the fractures, the experiment measured the permeability of the system, including proppants accumulated on the inlet, and could not effectively map the internal changes. This, therefore, needs to be considered when an experimental program for proppant injection is executed. To accurately monitor the internal changes, application of digital rock technology is recommended for such experiments

Stress corrosion cracking of rockbolts: An in-situ testing approach

Premature failure of rockbolts due to stress corrosion cracking (SCC) is an unresolved global issue in underground structures, particularly underground mines. To date, SCC of rockbolts has been produced in laboratory-based studies under laboratory conditions, however no attempt to produce SCC in-situ in actual underground coal mine conditions has previously been made. In this study, an innovative testing methodology was used in which a rockbolt coupon was developed with multiple stressed sections. The test coupon could be placed in-situ within a borehole in an underground mine, exposing it to the borehole environment, the surrounding rock strata and the groundwater. In-situ coupons were made from both 1355 and HSAC840 grade rockbolt steels and installed within a typical rockbolted horizon where known SCC failure of rockbolts had occurred. SCC occurred in the 1355 grade in-situ coupons, but not in the HSAC840 grade ones despite service failures of HSAC840 rockbolts having occurred in the same underground mine. The difference in behaviour of the HSAC840 coupons and in-service rockbolts is most likely due to different stress regimes acting on the coupons and the rockbolts. Localised corrosion was observed on both steels although analysis of the groundwater indicated that it had low corrosivity. Microbiological analysis showed that a range of bacteria known to be involved in corrosion were present on the rockbolt coupons and in the underground environment. This suggested that the occurrence of localised corrosion and SCC in low corrosivity groundwater could be due to the presence of microbial organisms, in particular, sulphate reducing bacteria. The results of this study provide detailed insights into the SCC of rockbolts in the underground environment. The method developed here can be used to study other reinforcement elements and stressed settings for stress corrosion cracking