Forecasting model of activities of the city-level for management of CO2 emissions applicable to various cities.

CO2 reduction has become one of the most critical issues globally, and considering sustainable development, many countries are implementing and reviewing CO2 reduction policies. To examine the effect of the CO2 reduction policies, a forecasting model that considers the relationship between variables such as population, building area, industries, vehicle use, and the environment is required. Moreover, this model should also be applicable to various cities to support effective policymaking. In this study, we develop a model that can predict CO2 emissions from the relationship between the variables using System Dynamics, a method to model cities to represent one system composed of various variables. To expand the applicability of the model to various cities in Japan, the proposed model assigns statistical data as input data that can be obtained in any city and standardizes the system structure and variables of the model. In this study, we selected three cities, namely Fukuoka, Kashiwa, and Kumano, which had different populations and industrial characteristics. The calculation accuracy error of CO2 emissions for the three cities was found to be less than 6%. In addition, through the parameter study, it was confirmed that the proposed model can be used to examine the sectors that require CO2 reduction policies, along with the optimal application period. This study aims to provide an effective model that can help in CO2 forecasting and thus in environmental and sustainable development policymaking. Our approach to the CO2 forecasting model facilitates calculating effective CO2 reductions in various cities.

Novel culture technique involving an histone deacetylase inhibitor reduces the marginal islet mass to correct streptozotocin-induced diabetes.

Islet transplantation is limited by the difficulties in isolating the pancreatic islets from the cadaveric donor and maintaining them in culture. To increase islet viability and function after isolation, here we present a novel culture technique involving an histone deacetylase inhibitor (HDACi) to rejuvenate the isolated islets. Pancreatic islets were isolated from Sprague-Dawley (SD) rats and one group (FIs; freshly isolated islets) was used after overnight culture and the other group (RIs; rejuvenated islet) was subjected to rejuvenation culture procedure, which is composed of three discrete steps including degranulation, chromatin remodeling, and regranulation. FIs and RIs were compared with regard to intracellular insulin content, glucose-stimulated insulin secretion (GSIS) capacity, gene expression profile, viability and apoptosis rate under oxidative stresses, and the engraftment efficacy in the xenogeneic islet transplantation models. RIs have been shown to have 1.9 ± 0.28- and 1.7 ± 0.31-fold greater intracellular insulin content and GSIS capacity, respectively, than FIs. HDACi increased overall histone acetylation levels, with inducing increased expression of many genes including insulin 1, insulin 2, GLUT2, and Ogg1. This enhanced islet capacity resulted in more resistance against oxidative stresses and increase of the engraftment efficacy shown by reduction of twofold marginal mass of islets in xenogeneic transplantation model. In conclusion, a novel rejuvenating culture technique using HDACi as chromatin remodeling agents improved the function and viability of the freshly isolated islets, contributing to the reduction of islet mass for the control of hyperglycemia in islet transplantation.

A fibrin gel carrier system for islet transplantation into kidney subcapsule.

Islet transplantation is a promising therapeutic option for type 1 diabetes, and actively performed in the clinic as well as in the animal experiments. For the rodent experiments, islet transplantation into kidney subcapsule is widely used to assess islet quality, however, it is often difficult to do using a polyethylene tubing and fine needle because of inherent dead volume of needle and stickiness of the tubing to islets. This problem makes it difficult to interpret the physiological response to different islet doses. Here, we developed a simple fibrin gel carrier system for islet transplantation into kidney subcapsule and utilized it to determine the marginal islet mass sufficient for correction of hyperglycemia in diabetic nude mice.