The most preferred decellularization technique in creating bioscaffolds for complex organs such as kidneys is through detergent perfusion. Detergents such as sodium dodecyl sulfate (SDS) flow to the ...kidneys to remove cells but using this technique alone requires long treatment times. Coupling this technique with sonication treatment decreases decellularization time but may cause damages in the microarchitecture of the kidney. This study evaluated the effects of decellularization parameters specifically SDS concentration (0.25%, 0.625%, and 1.0%wt/vol), flowrate (15, 30, and 45 mL/min), and sonicator power (0, 60, and 120 W) on the length of time needed to produce acellular and intact bioscaffolds. Decellularization was carried out by perfusing SDS to the renal artery of the cadaveric porcine kidney while exposed to sonication treatment. Results showed that a significant decrease in decellularization time was observed in producing acellular scaffold when perfusion decellularization was coupled with sonication. In addition, SDS concentration, SDS flowrate, and sonicator power had significant effects on the decellularization time while only sonicator power had a significant effect on the microarchitecture integrity of the scaffold. Lastly, H&E results showed that the produced bioscaffold showed complete cell removal with only minimal to moderate disruptions on the microarchitecture of the kidney.
Chronic wounds, known for their prolonged healing and the associated financial strain on patients, highlight the growing need for effective monitoring methods. One approach to handling chronic wounds ...involves monitoring biomarkers, with pH emerging as a promising option. Halochromic sensors, designed to detect color changes in response to pH fluctuations, can be employed for monitoring pH variations in wounds. Previous studies have demonstrated the utility of halochromic-based materials in the field of wound management. Nevertheless, it is worth noting that data derived from such sensors may be prone to misinterpretation, particularly when subjected to human visual processing. Hence, this paper aims to develop a pH prediction system based on the fabricated polymer's extracted values of different color channels. As a feature selection, principal component analysis (PCA) was performed to determine the number of significant features, and neighborhood component analysis (NCA) was conducted to eliminate the unrelated elements. Subsequently, an RNN model was developed and enhanced through the application of three distinct metaheuristic optimization algorithms: chernobyl disaster optimizer (CDO), chaos game optimizer (CGO), and coronavirus herd immunity optimization algorithm (CHIO). Following the simulation and evaluation of each optimized RNN model, the CGO-RNN model exhibited the lowest mean squared error (MSE) value of 0.1583, indicating that the RNN with chaos game optimizer stands out as the most effective model for this particular application.
Kidney problems rank 7th among the top 10 causes of mortality among Filipinos. One of the potential future treatment options is the use of bioengineered kidney. The preparation of scaffolds is the ...first step in kidney bioengineering and perfusion decellularization using chemicals is considered the most preferred preparation method to date. However, the use of chemicals alone requires long treatment time hence, in this study perfusion decellularization is to be enhanced by sonication treatment at varying sonication power. Decellularization was carried out by perfusing the kidney with 1% SDS and was subjected to sonication treatment with a 2h sonication and 2h rest cycle. The cycle is repeated until the kidney is clear and transparent. Washing using 1% Triton X-100 and 1x PBS then follows to remove residual SDS. The extent of cell removal was determined by H&E staining. The results showed that decellularization with sonication using 150W, 200W and 250W required a treatment time of 24h, 16h and 12h respectively compared to the 28h treatment time of decellularization without sonication. The result clearly shows that with higher sonication power, the shorter is the decellularization time needed to prepare a good kidney scaffold.
Regulating Household Leverage DEFUSCO, ANTHONY A.; JOHNSON, STEPHANIE; MONDRAGON, JOHN
Review of economic studies/The review of economic studies,
03/2020, Letnik:
87, Številka:
2 (313)
Journal Article
Recenzirano
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This article studies how credit markets respond to policy constraints on household leverage. Exploiting a sharp policy-induced discontinuity in the cost of originating certain high-leverage ...mortgages, we study how the Dodd–Frank “Ability-to-Repay” rule affected the price and availability of credit in the U.S. mortgage market. Our estimates show that the policy had only moderate effects on prices, increasing interest rates on affected loans by 10–15 basis points. The effect on quantities, however, was significantly larger; we estimate that the policy eliminated 15% of the affected market completely and reduced leverage for another 20% of remaining borrowers. This reduction in quantities is much greater thanwould be implied by plausible demand elasticities and indicates that lenders responded to the policy not only by raising prices but also by exiting the regulated portion of the market. Heterogeneity in the quantity response across lenders suggests that agency costs may have been one particularly important market friction contributing to the large overall effect as the fall in lending was substantially larger among lenders relying on third-parties to originate loans. Finally, while the policy succeeded in reducing leverage, our estimates suggest this effect would have only slightly reduced aggregate default rates during the housing crisis.
We study how employment documentation requirements and out-of-pocket closing costs constrain mortgage refinancing. These frictions, which bind most severely during recessions, may significantly ...inhibit monetary policy pass-through. To study their effects on refinancing, we exploit a Federal Housing Administration policy change that excluded unemployed borrowers from refinancing and increased others' out-ofpocket costs substantially. These changes dramatically reduced refinancing rates, particularly among the likely unemployed and those facing new out-of-pocket costs. Our results imply that unemployed and liquidity-constrained borrowers have a high latent demand for refinancing. Cyclical variation in these factors may therefore affect both the aggregate and distributional consequences of monetary policy.
Abstract
Using household-level debt data over 2000–2012 and local variation in inequality, we show that low-income households in high-inequality regions (zip codes, counties, states) accumulated less ...debt relative to their income than low-income households in lower inequality regions. We also find evidence that low-income households face higher credit prices and reduced access to credit as inequality increases. We argue that these patterns are consistent with inequality tilting credit supply away from low-income households and toward high-income households, which may have long-run implications for outcomes like homeownership or entrepreneurship.
Inhalt: Introduction -- The roots of public education in New Mexico -- Governance of public education in New Mexico -- Indian education in New Mexico -- Education as a profession -- Curriculum -- ...Financing schools in New Mexico -- School improvements and educational reform -- Public education and higher education connection -- Future trends -- Epilogue.
This dissertation provides evidence on the effects of changes in the supply of credit to households during the 2000s on employment and other outcomes of interest during the 2000s. In the first ...chapter I study the effects of contractions in household credit supply during the financial crisis of 2007-2009. I exploit a county’s exposure to the collapse of a large and previously healthy lender as a natural experiment. I show that exposure to this shock appears to be uncorrelated with other important shocks at the time. Reduced form estimates suggest that this shock had large effects on the flow of credit, housing and non-housing expenditures, and employment. Using exposure to this shock as an instrument gives an estimated elasticity of employment with respect to household credit of about 0.3, caused by declines in both housing and non-housing demand. In the second chapter I study the size of the credit supply shock using non-parametric methods. I identify lender-specific supply-side shocks, which I then aggregate into a simple measure of credit supply shocks to counties. I provide conditions under which this measured shock can be used to quantify the importance of supply shocks to credit in both the cross-section and, in a partial equilibrium sense, the aggregate. Combining this measure with various estimates of the elasticity of employment with respect to the measure, I calculate that shocks to household credit can be responsible for 30 to 60% of the decline in employment from 2007 to 2010.
What explains record U.S. house price growth since late 2019? We show that the shift to remote work explains over one half of the 23.8 percent national house price increase over this period. Using ...variation in remote work exposure across U.S. metropolitan areas we estimate that an additional percentage point of remote work causes a 0.93 percent increase in house prices after controlling for negative spillovers from migration. This cross-sectional estimate combined with the aggregate shift to remote work implies that remote work raised aggregate U.S. house prices by 15.1 percent. Using a model of remote work and location choice we argue that this estimate is a lower bound on the aggregate effect. Our results imply a fundamentals-based explanation for the recent increases in housing costs over speculation or financial factors, and that the evolution of remote work is likely to have large effects on the future path of house prices and inflation.
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