Computational analysis of radiative heat transfer due to rotating tube in parabolic trough solar collectors with Darcy Forchheimer porous medium

This attempt numerically investigates the heat transfer in parabolic trough solar collectors due to the rotating tube for the hybrid nanofluid flow over the Riga surface with Darcy Forchheimer’s porous medium under the effect of solar radiation. The influences of viscous dissipation and Joule heating are also considered. Equations governing the fluid flow are non-dimensionalized by implementing appropriate similarity variables. The resulting non-dimensionalized ordinary differential equations are solved using the shooting technique with Adam Bashforth and Adam Moulten’s fourth-order numerical approach. The numerical outcomes for various influential physical parameters regarding the fluid velocity, temperature, Nusselt number, and entropy generation are presented in graphical form. It is observed that the thermal profile escalates with the higher values of Reynold’s number, modified magnetic field parameter, and Prandtl number. Also, the Nusselt number diminishes with augmenting values of the Eckert number, modified magnetic field parameter, Forchheimer number, and Darcy number. The optimization of heat transfer in parabolic trough collectors is essential to improve the performance of solar collectors. The concentrated solar power technology is adequate for storing radiation energy in higher amounts.Author U.F.-G. appreciates the support of the Government of the Basque Country, Grant N. ELKARTEK 22/85 and ELKARTEK 21/10. The research is supported by Researchers Supporting Project number (RSP2023R158), King Saud University, Riyadh, Saudi Arabia

Unintended Consequences of the Dodd–Frank Act on Credit Rating Risk and Corporate Finance

Prior research finds that Dodd–Frank Act’s regulations on credit rating agencies (CRAs) increase rated firms’ risk of rating downgrades, regardless of their credit quality. Our difference-in-difference estimates suggest that after Dodd–Frank, low-rated firms, which face steep costs from a further downgrade, significantly reduce their debt issuance and investments compared to similar unrated firms. Our results are not driven by credit supply or the financial crisis. They reveal an unintended consequence of Dodd–Frank: Greater regulatory pressure on CRAs leads to negative spillover effects on firms concerned about credit ratings, regardless of their credit quality

Gelatin-based 3D conduits for transdifferentiation of mesenchymal stem cells into Schwann cell-like phenotypes

In this study, gelatin-based 3D conduits with three different microstructures (nanofibrous, macroporous and ladder-like) were fabricated for the first time via combined molding and thermally induced phase separation (TIPS) technique for peripheral nerve regeneration. The effects of conduit microstructure and mechanical properties on the transdifferentiation of bone marrow-derived mesenchymal stem cells (MSCs) into Schwann cell (SC) like phenotypes were examined to help facilitate neuroregeneration and understand material-cell interfaces. Results indicated that 3D macroporous and ladder-like structures enhanced MSC attachment, proliferation and spreading, creating interconnected cellular networks with large numbers of viable cells compared to nanofibrous and 2D-tissue culture plate counterparts. 3D-ladder-like conduit structure with complex modulus of ∼0.4 × 106 Pa and pore size of ∼150 μm provided the most favorable microenvironment for MSC transdifferentiation leading to ∼85% immunolabeling of all SC markers. On the other hand, the macroporous conduits with complex modulus of ∼4 × 106 Pa and pore size of ∼100 μm showed slightly lower (∼65% for p75, ∼75% for S100 and ∼85% for S100β markers) immunolabeling. Transdifferentiated MSCs within 3D-ladder-like conduits secreted significant amounts (∼2.5 pg/mL NGF and ∼0.7 pg/mL GDNF per cell) of neurotrophic factors, while MSCs in macroporous conduits released slightly lower (∼1.5 pg/mL NGF and 0.7 pg/mL GDNF per cell) levels. PC12 cells displayed enhanced neurite outgrowth in media conditioned by conduits with transdifferentiated MSCs. Overall, conduits with macroporous and ladder-like 3D structures are promising platforms in transdifferentiation of MSCs for neuroregeneration and should be further tested in vivo. Statement of Significance This manuscript focuses on the effect of microstructure and mechanical properties of gelatin-based 3D conduits on the transdifferentiation of mesenchymal stem cells to Schwann cell-like phenotypes. This work builds on our recently accepted manuscript in Acta Biomaterialia focused on multifunctional 2D films, and focuses on 3D microstructured conduits designed to overcome limitations of current strategies to facilitate peripheral nerve regeneration. The comparison between conduits fabricated with nanofibrous, macroporous and ladder-like microstructures showed that the ladder-like conduits showed the most favorable environment for MSC transdifferentiation to Schwann-cell like phenotypes, as seen by both immunolabeling as well as secretion of neurotrophic factors. This work demonstrates the importance of controlling the 3D microstructure to facilitate tissue engineering strategies involving stem cells that can serve as promising approaches for peripheral nerve regeneration.US Army Medical Research and Materiel Command (W81XWH-11-1-0700); Stem Cell Biology Fund; Stanley Endowed Chai

In Vitro and In Vivo effects of suppressor of cytokine signalling 7 knockdown in breast cancer: the influence on cellular response to hepatocyte growth factor

Purpose. Suppressor of cytokine signaling 7 (SOCS7) is a member of the SOCS family and is known to interact with phospholipase Cγ-1 (PLCγ-1), a key downstream mediator of the hepatocyte growth factor (HGF)/C-MET axis. Here, we report our observations of the effect of knocking down SOCS7 gene on the behaviour of breast cancer cells both in vitro and in vivo and to elucidate whether this involves HGF/C-MET pathway using the PLCγ-1 blocker U73122. Methods. MCF7 and MDA-MB-231 breast cancer cells were transfected with anti-SOCS7 ribozymal transgene, to create sublines with SOCS7 knockdown. The in vitro growth and migration of the cells were evaluated in basic conditions and with HGF and U73122 treatment using growth assays, scratch-wound, and electrical cell impedance sensing (ECIS) migration assays. MCF7 and MDA-MB-231 in vivo tumour xenograft growth were also studied. Results. Basal in vitro growth and migration of both cellular lines and the in vivo MCF7 xenograft growth were significantly enhanced with SOCS7 knockdown. In vitro HGF treatment has further influenced the growth and migration when SOCS7 gene was knocked-down in both cellular lines . PLCγ-1 pharmacological inhibition of the HGF/C-MET cascade during their in vitro growth and migration seemed to only occur when SOCS7 gene was knocked down. Conclusions. We report a unique regulatory role for SOCS7 in controlling the malignant behaviour of breast cancer lines MCF7 and MDA-MB-231 in vitro and the MCF7 tumour xenografts in vivo. We also report a regulatory role for SOCS7 during the in vitro HGF-induced growth and migration in these cells as HGF treatment and SOCS7 loss have synergistically enhanced these functions. This SOCS7 knockdown-attributed effect could be due to a precise anti-PLCγ-1 role

Capsular synovial metaplasia mimicking silicone leak of a breast prosthesis: a case report

<p>Abstract</p> <p>Introduction</p> <p>Synovial metaplasia around a prosthesis and in particular around silicone breast implants has been noted by various investigators, but has unknown clinical significance. We report on a patient where a large amount of synovial fluid mimicked rupture of an implant. We believe this to be an unusual clinical presentation of this phenomenon. Review of the English language literature failed to identify a comparable case.</p> <p>Case presentation</p> <p>A 25-year-old woman had undergone bilateral breast augmentation for cosmetic reasons. One implant was subsequently subjected to two attempts at expansion to correct asymmetry. The patient was later found to have a large quantity of viscous fluid around the port of that same prosthesis. Histological assessment of the implant had consequently confirmed capsular synovial metaplasia. This had initially caused the suspicion of a silicone 'bleed' from the implant and had resulted in an unnecessary explantation.</p> <p>Conclusion</p> <p>Capsular synovial metaplasia should be ruled out before the removal of breast implants where a leak is suspected. Manipulation and expansion of an implant may be risk factors for the development of synovial metaplasia.</p

Clinical significance of PD1 and PDL1 in human breast cancer

Background/Aim: Programmed death 1 (PD1) and its ligand programmed death ligand 1 (PDL1) form a pathway which when activated is thought to result in suppression of antitumor adaptive responses, influencing antitumor immunity. With potential targeted therapies emerging against PDL1, we investigated the clinical significance of mRNA expression levels of PD1 and PDL1 in our breast cancer cohort to explore its association with disease progression and prognosis. Previous studies evaluating the expression of PD1 and PDL1 (mRNA or protein) and its association with prognosis in breast cancer showed both positive and negative correlations and hence remain controversial. Materials and Methods: Quantitative polymerase chain reaction was used to determine transcript expression levels of PD1 and PDL1 in a cohort consisting of primary breast cancer tissues (n=127) and matching non-neoplastic background tissues (n=33) with available clinical and pathological information. Two-sample two-tailed t-test, Kaplan–Meier survival analysis and Wilcoxon tests were performed. Results: Significant PDL1 transcript level reductions were seen in patients who developed metastases, as well as those who had local recurrence, compared to patients who remained disease-free. Higher PDL1 transcript levels were also associated with better overall and disease-free survival. Significantly higher transcript expression levels of PD1 were found in tumor tissue, whilst a general increase in PDL1 expression was found in tumor tissues, although this did not reach statistical significance. Conclusion: Our study demonstrates higher levels of expression of PDL1 are associated with favorable clinical outcome

The role of death-associated protein 3 in apoptosis, anoikis and human cancer

Death-associated protein 3 (DAP3) is a molecule with a significant role in the control of both apoptosis and anoikis. Apoptosis is the predominant type of programmed cell death (PCD) which may occur in response to irreparable damage to DNA, or in response to induction by inflammatory cells. Anoikis is subset of apoptosis which occurs in epithelial cells in response to detachment from the surrounding matrix. Both apoptosis and anoikis are of interest in the context of carcinogenesis. In this review, we shall discuss apoptosis and anoikis, and the recent literature regarding the role of DAP3 in both these pathways

Higher expression levels of SOCS 1,3,4,7 are associated with earlier tumour stage and better clinical outcome in human breast cancer

Background Suppressors of cytokine signaling (SOCS) are important negative feedback regulators of the JAK/STAT signaling pathway, and have been recently investigated for their role in the development of different cancers. In this study, we examined the expression of SOCS1-7 genes in normal and breast cancer tissue and correlated this with several clinico-pathological and prognostic factors. Methods SOCS1-7 mRNA extraction and reverse transcription were performed on fresh frozen breast cancer tissue samples (n = 127) and normal background breast tissue (n = 31). Transcript levels of expression were determined using real-time PCR and analyzed against TNM stage, tumour grade and clinical outcome over a 10 year follow-up period. Results SOCS1,4,5,6 and 7 expression decreased with increased TNM stage (TNM1 vs. TNM3 p = 0.039, TNM1 vs. TNM4 p = 0.016, TNM2 vs. TNM4 p = 0.025, TNM1 vs. TNM3 p = 0.012, and TNM1 vs. TNM3 p = 0.044 respectively). SOCS2 and 3 expression decreased with increased Nottingham Prognostic Index (NPI) (NPI1 vs. NPI3 p = 0.033, and NPI2 vs. NPI3 p = 0.041 respectively). SOCS7 expression decreased with higher tumour grade (Grade 3 vs. Grade 2 p = 0.037). After a median follow up period of 10 years, we found higher levels of SOCS1,2 and 7 expression among those patients who remained disease-free compared to those who developed local recurrence (p = 0.0073, p = 0.021, and p = 0.039 respectively). Similarly, we found higher levels of SOCS 2,4, and 7 expression in those who remained disease-free compared to those who developed distant recurrence (p = 0.022, p = 0.024, and p = 0.033 respectively). Patients who remained disease-free had higher levels of SOCS1 and 2 expression compared to those who died from breast cancer (p = 0.02 and p = 0.033 respectively). The disease free survival (DFS) and overall survival (OS) curves showed that higher levels of SOCS1, 3 and 7 were significant predictors of higher DFS (p = 0.015, p = 0.024 and 0.03 respectively) and OS (p = 0.005, p = 0.013 and p = 0.035 respectively). Higher levels of SOCS 4 were significant in predicting better OS (p = 0.007) but not DFS. Immunohistochemical staining of representative samples showed a correlation between SOCS1, 3, 7 protein staining and the SOCS1, 3, 7 mRNA expression. Conclusion Higher mRNA expression levels of SOCS1, 3, 4 and 7 are significantly associated with earlier tumour stage and better clinical outcome in human breast cancer