Unique or Adjustable Business Model for Distributed Ledger Technology?

We examine whether business model concepts, that demonstrate significant convergence to Distributed Ledger Technology (DLT) attributes, fit to DLT ecosystem characteristics and identify similarities and deflections. We answer the question whether the appropriate DLT business model is totally unique or adjustable and what conditions need to be met. The study follows a conceptual approach that is based on critical examination of three business model types that demonstrate similarities to the business model that an organization needs to adopt in order to fit in DLT ecosystem characteristics. Although each one of the network, digital and information business model types demonstrate similarities to DLT business model and reveal some resemblance with it, there are critical parameters that are neither addressed nor partially met. The main contribution of study is the exploration of the adjustable nature of the DLT business. Moreover, we highlighted the challenge for DLT ecosystem sustainability, defined and reviewed the conditions that need to be considered for DLT business model design

The effect of preloading on the strength of jacketed R/C columns

The influence of core preloading on the strength of jacketed reinforced concrete (R/C) columns is analytically investigated. A recently proposed method for arbitrary composite section analysis in biaxial bending and axial load is extended to include preloading actions. A parametric evaluation of the preloading effect using quantitative indices is performed, considering the variability of several parameters such as section geometry, amount of reinforcement, and various axial and moment preloading levels. Results are presented in the form of 3D failure surfaces and moment-curvature curves. Specific cases where the preloading effect is more pronounced are finally highlighted

A FEM-based model to study the behavior of SRG-strengthened R/C beams

In this paper, a new time‐effective modeling approach is proposed for predicting the response of shear‐deficientreinforced concrete (R/C) beams strengthened with steel‐reinforced grout (SRG) jackets. Solid finite elementsare utilized for concrete using a fracture‐plasticity constitutive law, while both high‐strength steel cords andconventional reinforcement are modeled using embedded truss elements with multilinear stress–strain laws.The efficiency of the proposed method is assessed by comparing numerical against experimental data of nineshear‐deficient beams strengthened with various SRG jacketing configurations. The comparison demonstratedclose correlation both in terms of failure mode and force–displacement curves. The numerical analysis predicted the observed crack pattern and failure modes accurately, whereas deviation in terms of load and deflection was, on average, less than 1% and 10%, respectivel

Flexural behaviour of reinforced concrete jacketed columns under reversed cyclic loading

The objective of the present study is the development of an analytical model for predicting the response under reversed cyclic loading of structural members with ‘old-type’ detailing, strengthened with reinforced concrete (RC) jacketing. The analytical model introduces one additional degree of freedom between the existing member (core of the retrofitted member) and its outer RC shell, thus allowing slip to take place at the interface between the existing member and the jacket. Shear resistance mechanisms, such as aggregate interlock, friction, and dowel action, are mobilized to resist slip. Existing constitutive models are further improved to describe the mechanisms that resist sliding under cyclic shear reversals and implemented for the first time in an analytical model for deriving the response of RC jacketed members. A calculation algorithm is developed to estimate the flexural response under cyclic loading taking into account slip at the interfaces. The sensitivity of the proposed analytical model to the shear transfer mechanisms degradation rules, as well as to the crack spacing estimation, was evaluated. The validity of the proposed analytical model is assessed against experimental results

Transient aseismic vertical deformation across the steeply-dipping Pisia-Skinos normal fault (Gulf of Corinth, Greece)

Geodetically-derived deformation rates are sometimes used to infer seismic hazard, implicitly assuming that short-term (annual-decadal) deformation is representative of longer-term deformation. This is despite geological observations indicating that deformation/slip rates are variable over a range of timescales. Using geodetic data from 2016-2021, we observe an up to 7-fold increase in vertical deformation rate in mid-2019 across the Pisia-Skinos normal fault in Greece. We hypothesise that this deformation is aseismic as there is no temporally correlated increase in the earthquake activity (M\u3e1). We explore four possible physical mechanisms, and our preferred hypothesis is that the transient deformation is caused by centimetre-scale slip in the upper 5km of the Pisia fault zone. This is the first observation of shallow tectonic (i.e. not related to human activities) aseismic deformation on a normal fault globally. Our results suggest that continental normal faults can exhibit variable deformation over shorter timescales than previously observed, and thus care should be taken when utilising geodetic rates to quantify seismic hazard

Practical nonlinear analysis of unreinforced concrete tunnel linings

A comprehensive methodology for modelling, analyzing and assessing the structural response of unreinforced concrete tunnel linings is presented. Various modelling techniques are described, considering the plane finite element representation of the lining geometry, material constitutive laws, and boundary and interface conditions. Furthermore, all relevant external loading cases are studied, including gravity, environmental, fire, blast, and seismic loading. Potential pitfalls in the modelling and analysis procedures are identified and properly dealt with. The suggested methodology is finally applied to actual tunnel linings and the interpretation of the analysis results leads to important conclusions regarding the applicability of different analysis methods and the performance of unreinforced concrete linings

Leptin as a critical regulator of hepatocellular carcinoma development through modulation of human telomerase reverse transcriptase

<p>Abstract</p> <p>Background</p> <p>Numerous epidemiological studies have documented that obesity is associated with hepatocellular carcinoma (HCC). The aim of this study was to investigate the biological actions regulated by leptin, the obesity biomarker molecule, and its receptors in HCC and the correlation between leptin and human telomerase reverse transcriptase (hTERT), a known mediator of cellular immortalization.</p> <p>Methods</p> <p>We investigated the relationship between leptin, leptin receptors and hTERT mRNA expression in HCC and healthy liver tissue samples. In HepG2 cells, chromatin immunoprecipitation assay was used to study signal transducer and activator of transcription-3 (STAT3) and myc/mad/max transcription factors downstream of leptin which could be responsible for hTERT regulation. Flow cytometry was used for evaluation of cell cycle modifications and MMP1, 9 and 13 expression after treatment of HepG2 cells with leptin. Blocking of leptin's expression was achieved using siRNA against leptin and transfection with liposomes.</p> <p>Results</p> <p>We showed, for the first time, that leptin's expression is highly correlated with hTERT expression levels in HCC liver tissues. We also demonstrated in HepG2 cells that leptin-induced up-regulation of hTERT and TA was mediated through binding of STAT3 and Myc/Max/Mad network proteins on <it>hTERT </it>promoter. We also found that leptin could affect hepatocellular carcinoma progression and invasion through its interaction with cytokines and matrix mettaloproteinases (MMPs) in the tumorigenic microenvironment. Furthermore, we showed that histone modification contributes to leptin's gene regulation in HCC.</p> <p>Conclusions</p> <p>We propose that leptin is a key regulator of the malignant properties of hepatocellular carcinoma cells through modulation of hTERT, a critical player of oncogenesis.</p

Limits of Applicability of Conventional and Advance Pushover Analysis for Seismic Response Assessment

In this report, the applicability of conventional and advanced inelastic static (pushover) analysis for seismic response assessment is investigated. A methodology is first suggested for evaluating the performance of pushover methods, based on a quantitative measure for the difference in response between pushover and inelastic dynamic analysis which is deemed to be the most accurate, but still expensive numerical method available. This methodology is applied on a set of eight different structural systems, covering various levels of irregularity in plan and elevation, structural ductility and directional effects. An extensive series of pushover analysis results, monitored on various structural levels is presented and compared to inelastic dynamic analysis under various strong motion records. General conclusions on the applicability of inelastic static analysis for seismic response assessment are finally discussed.National Science Foundation EEC-9701785published or submitted for publicatio