Acute liver failure can be the consequence of various etiologies, with most cases arising from drug-induced hepatotoxicity in Western countries. Despite advances in this field, the management of ...acute liver failure continues to be one of the most challenging problems in clinical medicine. The availability of adequate experimental models is of crucial importance to provide a better understanding of this condition and to allow identification of novel drug targets, testing the efficacy of new therapeutic interventions and acting as models for assessing mechanisms of toxicity. Experimental models of hepatotoxicity related to acute liver failure rely on surgical procedures, chemical exposure or viral infection. Each of these models has a number of strengths and weaknesses. This paper specifically reviews commonly used chemical in vivo and in vitro models of hepatotoxicity associated with acute liver failure.
•The murine APAP model is very close to what is observed in patients.•The Gal/ET model is useful to study TNFα-mediated apoptotic signaling mechanisms.•Fas receptor activation is an effective model of apoptosis and secondary necrosis.•The ConA model is a relevant model of auto-immune hepatitis and viral hepatitis.•Multiple time point evaluation needed in experimental models of acute liver injury.
•Failure mechanism of thread-fixed one-side bolted T-stubs under tension was investigated through a finite element model.•Studied parameters included the bolt diameter, the bolt spacing and the ...T-stub plate strength.•Modified design equations integrating the potential hole thread failure were proposed.•Analysis results showed that the thread hole could provide enough clamping force to fix the high strength bolt.
The failure mechanism of thread-fixed one-side bolted T-stubs under tension was investigated by a finite element model to provide basic knowledge for its potential application in bolted beam-column endplate connection. The finite element model was verified through experimental results by considering four possible reference issues: the T-stub deformation, the force–displacement curve, the failure mode and the yield strength. Studied parameters included the bolt diameter (d), the bolt spacing (s) and the T-stub plate strength (fy). Based on numbers of plastic hinges in the T-stub flange, the failure modes were divided into three categories: Mode 1, complete flange yielding; Mode 2, flange yielding accompanied by bolt failure or hole thread failure; and Mode 3, bolt failure or hole thread failure. Furthermore, modified design equations integrating the potential hole thread failure were proposed to analyze the failure mode and the yield strength of the T-stub connection. Theoretical and numerical analyses showed that the thread hole could provide enough clamping force to fix the high strength bolt, which assured that the one-side bolted T-stub connection would not fail caused by pre-mature thread failure.
Entrepreneurs who start a business to serve both self-interests and collective interests by addressing unmet social and environmental needs are usually referred to as sustainable entrepreneurs. ...Compared with regular entrepreneurs, we argue that sustainable entrepreneurs face specific challenges when establishing their businesses owing to the discrepancy between the creation and appropriation of private value and social value. We hypothesize that when starting a business, sustainable entrepreneurs (1) feel more hampered by perceived barriers, such as the institutional environment and (2) have a different risk attitude and perception than regular entrepreneurs. We use two waves of the Flash Eurobarometer survey on entrepreneurship (2009 and 2012), which contains information on start-up motivations, start-up barriers, and risk perceptions of approximately 3000 (prospective) business owners across 33 countries. We find that sustainable entrepreneurs indeed perceive more institutional barriers in terms of a lack of financial, administrative, and informational support at business start-up than regular entrepreneurs. Further, no significant differences between sustainable and regular entrepreneurs are found in terms of their risk attitudes or perceived financial risks. However, sustainable entrepreneurs are more likely to fear personal failure than regular entrepreneurs, which is explained by their varied and complex stakeholder relations. These insights may serve as an important signal for both governments and private capital providers in enhancing the institutional climate.
Multicenter, retrospective series.
To analyze the incidence, mode, and location of acute proximal junctional failures (APJFs) after surgical treatment of adult spinal deformity.
Early proximal ...junctional failures above adult deformity constructs are a serious clinical problem; however, the incidence and nature of early APJFs remain unclear.
A total of 1218 consecutive adult spinal deformity surgeries across 10 deformity centers were retrospectively reviewed to evaluate the incidence and nature of APJF, defined as any of the following within 28 weeks of index procedure: minimum 15° post-operative increase in proximal junctional kyphosis, vertebral fracture of upper instrumented vertebrae (UIV) or UIV + 1, failure of UIV fixation, or need for proximal extension of fusion within 6 months of surgery.
Sixty-eight APJF cases were identified out of 1218 consecutive surgeries (5.6%). Patients had a mean age of 63 years (range, 26-82 yr), mean fusion levels of 9.8 (range, 4-18), and mean time to APJF of 11.4 weeks (range, 1.5-28 wk). Fracture was the most common failure mode (47%), followed by soft-tissue failure (44%). Failures most often occurred in the thoracolumbar region (TL-APJF) compared with the upper thoracic region (UT-APJF), with 66% of patients experiencing TL-APJF compared with 34% experiencing UT-APJF. Fracture was significantly more common for TL-APJF relative to UT-APJF (P = 0.00), whereas soft-tissue failure was more common for UT-APJF (P < 0.02). Patients experiencing TL-APJF were also older (P = 0.00), had fewer fusion levels (P = 0.00), and had worse postoperative sagittal vertical axis (P < 0.01).
APJFs were identified in 5.6% of patients undergoing surgical treatment of adult spinal deformity, with failures occurring primarily in the TL region of the spine. There is evidence that the mode of failure differs depending on the location of UIV, with TL failures more likely due to fracture and UT failures more likely due to soft-tissue failures.
A new dynamic model is established to formulate the cascading failure in the urban rail transit network based on the disaster spreading theory. Firstly, the weighted urban rail transit network by ...considering the time cost of each effective path is established, the transfer station and turn back station on the topological network are handled specifically, the Dijkstra algorithm is designed to solve the shortest path of each Origin-Destination. Then, the cascading failure model based on disaster spreading theory is established. Five factors including the failure evolution process with time, self-recovery ability of the nodes, failures spreading mechanism, passenger volume changes and the internal random noises by other influence factors are fully considered in this model. Finally, a real-world case study is conducted by using Chengdu Metro Network as the background. Eight simulation scenarios are established, the output is statistical number of failed stations. The results show that, the failed stations number has the greatest scale when fixed transfer stations are attacked. There is no obvious functional relationship between the scale of failure stations and self-recovery factor, and there is a positive correlation between self-recovery factor and cascading failure scale. Based on the results, five emergency resources allocation strategies are proposed.
This book presents 25 structural design smells (indicators of common design problems), their role in identifying design issues, and potential refactoring solutions. Organized across common areas of ...software design, each smell is presented with diagrams and examples illustrating the poor design practices and the problems that result, creating a catalog of nuggets of readily usable information that developers or engineers can apply in their projects. This resource presents a unique naming scheme for smells that helps understand the cause of a smell as well as points toward its potential refactoring; covers pragmatic techniques for refactoring design smells to manage technical debt and to create and maintain high-quality software in practice; and presents insightful anecdotes and case studies drawn from the trenches of real-world projects. --
The effect of strain rate on the failure mechanism of rocks is one of the most important aspects in the field of rock dynamics and has been considered in many research works due to its extensive ...application. This study focuses on dynamic features and failure mechanism of Brazilian disk specimens under high-rate loading. For this purpose, particle flow code 2-dimensional (PFC2D) was used for simulation of Brazilian disk samples. The numerical models were validated by comparing with results of uniaxial compression, Brazilian and Split-Hopkinson Pressure Bar (SHPB) laboratory tests and it is demonstrated that the result of numerical modeling has a good agreement with those of the experimental measurements. The validated numerical model was used for further study of the mechanical behavior of rock specimen at high strain rate. The results of numerical models revealed that there are three different of failure modes for Brazilian disk specimens at different strain rate: (1) tensile splitting failure mode for specimen at strain rate smaller than 150 (1/s), (2) branching failure mode when strain rate varies in range of 150–600 (1/s) and (3) crushing failure mode when the strain rate increases to more than 600 (1/s).
•Dynamic response of rock specimen at high strain rate was considered in this study.•Failure pattern of Brazilian disk specimens is influenced by strain rate.•With Increasing of strain rate, the number of induced shear fractures increases.•Effect of precrack on strength of CSCBD samples reduce with increasing of strain rate.
Dump slope failure has become a recurring incident in Nigeria’s major mine sites while the visible signs of instability in Nigeria’s waste rock dumps are the most dangerous situation. This paper aims ...to present intrinsic poor safety conditions of dump slopes in Nigerian mines. Twenty-one samples were collected from three mining provinces (7 samples from each province) and were subjected to various geotechnical tests such as particle size distribution, Atterberg limits, triaxial, compaction, consolidation and permeability tests. Results obtained were analyzed using numerical simulation models. From the laboratory data, the waste dumps were proven to be cohesive materials despite their high sand content. The wastes were described by the geo-mechanical characterization of the samples as competent materials with moderate strength and low compressibility, indicating materials with intermediate engineering capabilities. However, both field observation and numerical simulation of the waste dumps revealed that high slope height and angle, as well as excessive material saturation caused by high seasonal rainfalls, could compromise the stability of the dump slopes. According to stability analysis, the most crucial failure modes would be superficial plane and polygonal failures, as well as deep circular failures on rare occasions, all of which are governed by the mines' local geology. The waste dumps’ factor of safety, probability of failure and reliability index values all suggested slope instability, especially during the rainy season. To prevent future waste dump slope failures, the authors advocate recycling and reusing waste rocks as engineering materials, particularly for tailing dam structures.
Platforms and ecosystems provide structures for constellations of economic actors to engage and interact as they seek to create and capture value. We consider how the constructs of platforms and ...ecosystems relate and explore why they have become more ubiquitous by focusing on the nature of their value-add. We propose that they emerge as a response to distinct market failures, which we identify, and we explain which specific externalities they help overcome. We also identify post-hoc endogenous functional and distributional failures that platforms and ecosystems, in turn, generate. We discuss implications for theory and practice.
•Platforms and ecosystems emerge as new organizational forms that provide distinct ways to cope with externalities and as such address market (or organizational) failures.•While the two terms have emerge from different traditions, and are clearly connected, we can usefully distinguish between the two, and showcase their connections.•We can identify distinct coordination and value creation mechanisms in platforms and ecosystems, driven by complementarities and externalities.•Platforms and ecosystems, in turn, engender their own types of functional, distributional and social failures.•Ecosystems’ growing scope illustrates the distinction between multi-product and multi-actor groups, and suggests that the topology of ecosystems will help guide strategy and policy.
This paper proposes a methodology for managing complex sewerage networks based on the concomitant use of two performance evaluation methods, namely, the failure modes, effects, and criticality ...analysis (FMECA) and the analytical hierarchy process (AHP). The FMECA is used to determine the risks of structural failures making it possible to establish a methodology for managing these failures. The AHP is used to check the relationship consistency between the performance indicators allowing the determination of the overall performance (OP). This proposed methodology was utilized for the urban sewerage network of Oued-Kniss in the city of Algiers, Algeria, as part of the efforts engaged in for sustainable and efficient management.
PDF
