This work presents a steady-state model of a generic liquid air power plant integrated with parabolic trough solar collectors, explores the plant design space, and maximizes its energy and exergy ...performance. The model is verified against the round trip efficiency of various plant configurations reported in the literature, and the design space exploration entails quantifying the effects of plant mass flow rates, operating pressures, and heat exchanger inventory allocation on the global performance. The multi-objective optimization consists of maximizing both the round-trip and exergy efficiency and identifying their trade-offs via the Pareto front. Results demonstrate the presence of a critical liquid air mass flow rate beyond which reverse cooling is instigated and the plant performance is degraded. Furthermore, the two objective functions in the optimization are shown to compete against each other, although the round trip efficiency is deemed as a more practical performance metric while the maximum exergy efficiency design better exploits solar energy as a high-grade heat source. The best design for the plant layout under analysis yields the round trip and exergy efficiency of 20% and 59%, respectively, with the critical mass flow rate of 0.8 kg/s.
•Solar-driven liquid air power plant is modeled and explored.•Plant energy and exergy performance are maximized via multi-objective optimization.•Identified the presence of a critical liquid air mass flow rate.•Maximum energy and maximum exergy designs do not coincide.•Maximum exergy design better exploits solar energy as a high-grade heat source.
Oral squamous cell carcinoma (OSCC) is the most common head and neck cancer characterized by aggressive local invasion and metastasis. The pathogenesis of OSCC is mainly due to the accumulation of ...genetic alterations in epithelial cells, but the underlying mechanism for its development remains unclear. Here, we found that the expression level of regulator of G protein signaling 12 (RGS12) was significantly reduced in human OSCC. To understand the role and mechanism of RGS12 in OSCC, we generated a novel RGS12 global knockout (CMVCre/+; RGS12fl/fl) mouse model by crossing RGS12fl/fl mice with CMV-Cre transgenic mice and then further induced the mice to develop OSCC by using 4-nitroquinoline 1-oxide (4NQO). Deletion of RGS12 exhibited aggressive OSCC in the tongue compared with the control RGS12fl/fl mice. Knockdown of RGS12 in OSCC cells significantly increased cell proliferation and migration. Mechanistically, we found that RGS12 associated with phosphatase and tension homolog (PTEN) via the PDZ domain to upregulate the phosphorylation and SUMOylation of PTEN and then correspondingly inactivated the AKT/mTOR signaling pathway. To test the potential therapeutic effect of RGS12 on OSCC, we overexpressed RGS12 in OSCC cells and found a significant inhibition of cancer cell proliferation and migration. Moreover, subcutaneous inoculation of RGS12-overexpressed OSCC cells in NOD scid mice showed a significant reduction in tumor formation. Our findings reveal that RGS12 is an essential tumor suppressor and highlights RGS12 as a potential therapeutic target and prognostic biomarker of OSCC.
Background
While the majority of studies report that a raised serum α‐fetoprotein (AFP) level before operation is associated with a high risk of recurrence and death in patients who undergo ...hepatectomy for hepatocellular carcinoma (HCC), results are conflicting. The aim of this study was to assess the prognostic value of AFP.
Methods
Serum AFP levels were measured in patients with hepatitis‐associated HCC who underwent hepatectomy between 1995 and 2012. Kaplan–Meier and multivariable analyses were performed to identify risk factors for overall and disease‐free survival. Univariable and multivariable Cox proportional hazards regression was used to evaluate the predictive value of AFP. Receiver operating characteristic (ROC) curves were generated to identify the AFP level that had the highest accuracy in discriminating between survivors and non‐survivors.
Results
Some 376 patients with hepatitis B virus (HBV)‐associated HCC were included in the study. The overall survival rate was 58·8 per cent in patients with an AFP level of 400 ng/ml or less compared with 40·4 per cent for those with a level exceeding 400 ng/ml (P = 0·001). AFP concentration above 400 ng/ml was an independent risk factor for shorter disease‐free and overall survival after surgery. ROC analysis indicated that the optimal cut‐off values for AFP varied for different subtypes of HCC. The sensitivity and specificity were lower with areas under the ROC curve of less than 0·600. An AFP level greater than 400 ng/ml was not sensitive enough to predict the prognosis in patients with an HCC diameter smaller than 3 cm.
Conclusion
A serum AFP level above 400 ng/ml predicts poor overall and recurrence‐free survival after hepatectomy in patients with HBV‐associated HCC. AFP is not a strong prognostic marker given its poor discriminatory power, with low sensitivity and specificity.
Not useful
The interactions that lead to the emergence of superconductivity in iron-based materials remain a subject of debate. It has been suggested that electron-electron correlations enhance electron-phonon ...coupling in iron selenide (FeSe) and related pnictides, but direct experimental verification has been lacking. Here we show that the electron-phonon coupling strength in FeSe can be quantified by combining two time-domain experiments into a “coherent lock-in” measurement in the terahertz regime. X-ray diffraction tracks the light-induced femtosecond coherent lattice motion at a single phonon frequency, and photoemission monitors the subsequent coherent changes in the electronic band structure.Comparison with theory reveals a strong enhancement of the coupling strength in FeSe owing to correlation effects. Given that the electron-phonon coupling affects superconductivity exponentially, this enhancement highlights the importance of the cooperative interplay between electron-electron and electron-phonon interactions.
As an integrated part of a supply contract, trade credit has intrinsic connections with supply chain coordination and inventory management. Using a model that explicitly captures the interaction of ...firms’ operations decisions, financial constraints, and multiple financing channels (bank loans and trade credit), this paper attempts to better understand the risk-sharing role of trade credit—that is, how trade credit enhances supply chain efficiency by allowing the retailer to partially share the demand risk with the supplier. Within this role, in equilibrium, trade credit is an indispensable external source for inventory financing, even when the supplier is at a disadvantageous position in managing default relative to a bank. Specifically, the equilibrium trade credit contract is net terms when the retailer’s financial status is relatively strong. Accordingly, trade credit is the only external source that the retailer uses to finance inventory. By contrast, if the retailer’s cash level is low, the supplier offers two-part terms, inducing the retailer to finance inventory with a portfolio of trade credit and bank loans. Further, a deeper early-payment discount is offered when the supplier is relatively less efficient in recovering defaulted trade credit, or the retailer has stronger market power. Trade credit allows the supplier to take advantage of the retailer’s financial weakness, yet it may also benefit both parties when the retailer’s cash is reasonably high. Finally, using a sample of firm-level data on retailers, we empirically observe the inventory financing pattern that is consistent with what our model predicts.
This paper was accepted by Vishal Gaur, operations management.
Trade credit and supplier competition Chod, Jiri; Lyandres, Evgeny; Yang, S. Alex
Journal of financial economics,
02/2019, Letnik:
131, Številka:
2
Journal Article
Recenzirano
Odprti dostop
This paper examines how competition among suppliers affects their willingness to provide trade credit financing. Trade credit extended by a supplier to a cash constrained retailer allows the latter ...to increase cash purchases from its other suppliers, leading to a free rider problem. A supplier that represents a smaller share of the retailer’s purchases internalizes a smaller part of the benefit from increased spending by the retailer and, as a result, extends less trade credit relative to its sales. In consequence, retailers with dispersed suppliers obtain less trade credit than those whose suppliers are more concentrated. The free rider problem is especially detrimental to a trade creditor when the free-riding suppliers are its product market competitors, leading to a negative relation between product substitutability among suppliers to a given retailer and trade credit that the former provide to the latter. We test the model using both simulated and real data. The estimated relations are consistent with the model’s predictions and are statistically and economically significant.
This paper proposes a stator winding fault detection for interior permanent-magnet (PM) machines based on the pulsating-type voltage injection. By superimposing a pulsating voltage on d-axis with ...respect to the rotor-referred synchronous frame, measurable winding fault reflected signals occur in the injection induced current ripples. Comparing to prior diagnostic techniques, the proposed injection method is immune to the rotor saliency because saliency reflected current harmonic is decoupled once the pulsating voltage is exactly injected on rotor d-axis. It results in the improved fault detection performance on interior PM (IPM) machines as well as other salient machines. An IPM machine with three sets of turn-to-turn short is built to verify the proposed fault detection method.
Periodontitis is a complex inflammatory disease affecting the supporting structures of teeth and is associated with systemic inflammatory disorders. Regulator of G-protein signaling 12 (RGS12), the ...largest protein in the RGS protein family, plays a crucial role in the development of inflammation and bone remodeling. However, the role and mechanism(s) by which RGS12 may regulate periodontitis have not been elucidated. Here, we showed that ablation of RGS12 in Mx1+ hematopoietic cells blocked bone loss in the ligature-induced periodontitis model, as evidenced morphometrically and by micro–computed tomography analysis of the alveolar bone. Moreover, hematopoietic cell-specific deletion of RGS12 inhibited osteoclast formation and activity as well as the production of inflammatory cytokines such as IL1β, IL6, and TNFα in the diseased periodontal tissue. In the in vitro experiments, we found that the overexpression of RGS12 promoted the reprogramming of macrophages to the proinflammatory M1 type, but not the anti-inflammatory M2 type, and enhanced the ability of macrophages for migration. Conversely, knockdown of RGS12 in macrophages inhibited the production of inflammatory cytokines and migration of macrophages in response to lipopolysaccharide stimulation. Our results demonstrate for the first time that inhibition of RGS12 in macrophages is a promising therapeutic target for the treatment of periodontitis.
Catechins are widely occurring in our diet and beverages. The cancer-preventive activities of catechins have been extensively studied. Of these, (-)-epigallocatechin-3-gallate (EGCG), the principal ...catechin in green tea, has received the most attention. The inhibitory activities of tea catechins against carcinogenesis and cancer cell growth have been demonstrated in a large number of laboratory studies. Many mechanisms for modulating cancer signaling and metabolic pathways have been proposed based on numerous studies in cell lines with EGCG, the most active tea catechin. Nevertheless, it is not known whether many of these mechanisms indeed contribute to the anti-cancer activities in animals and in humans. Human studies have provided some results for the cancer preventive activities of tea catechins; however, the activities are not strong. This article reviews the cancer preventive activities and mechanisms of action of tea catechins involving their redox activities, biochemical properties and binding to key enzymes or signal transduction proteins. These mechanisms lead to suppression of cell proliferation, increased apoptosis and inhibition of angiogenesis. The relevance of the proposed mechanisms for cancer prevention are assessed in the light of the situation in vivo. The potential and possible problems in the application of tea and tea-derived products for cancer prevention are discussed.
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