Lithium ion batteries are widely used in portable electronic devices and electric vehicles. Altho... more Lithium ion batteries are widely used in portable electronic devices and electric vehicles. Although battery technology has been significantly improved, it does not fully meet the energy requirements of electric vehicles. Electric vehicle batteries are built by serial and parallel connections of many cells to provide sufficient power. Differences between cells during battery usage can shorten the battery life and even worse can cause fire and explosion. Therefore, there is a need for a battery management system to ensure that the voltage, temperature and current information of the battery cells are used as optimum conditions. Cell balancing should be used to ensure that the battery cells are charging simultaneously. Cell voltage and temperature are measured by connecting auxiliary slave board to each series battery pack. This information is controlled by a master board. In this application, the excess energy is converted to heat by the load resistor on the utility boards. Fuzzy logic control is used to control the load resistor with the switching element. The charge status of the battery was estimated using the main battery current and the mains voltage with the master board. This application has been tested on an electric vehicle. A low cost modular battery management system has been developed that can control the safe charging and discharging of the vehicle battery.
Insulin-induced normoglycemia has shown to have a beneficial effect on the outcome of pancreatic ... more Insulin-induced normoglycemia has shown to have a beneficial effect on the outcome of pancreatic islets transplanted to diabetic recipients. The aim of the study was to identify the insulin treatment that can maximize its beneficial effect on islet transplants. Six groups of streptozotocin diabetic C57B1/6 mice were transplanted (Tx) with 100 syngeneic islets, an insufficient beta cell mass to restore normoglycemia, and were treated with insulin as follows: group 1 (n = 9): from day 10 before Tx to day 14 after Tx; group 2 (n = 11): from day 6 before Tx to Tx day; group 3 (n = 11): from Tx day to day 6 after Tx; group 4 (n = 7): from Tx day to day 14 after Tx; group 5 (n = 8): from day 10 to day 24 after Tx; group 6 (n = 18): Tx mice were not treated with insulin. Sixty days after Tx, normoglycemia was achieved in 100% of mice in groups 1, 4, and 5, in 73% of mice in group 2, and in only 45% and 33% of mice in groups 3 and 6, respectively (p < 0.01). Intraperitoneal glucose toler...
To determine the factors at diagnosis predictive of changes in residual beta-cell function and me... more To determine the factors at diagnosis predictive of changes in residual beta-cell function and metabolic control in Type 1 diabetes, 125 patients older than 7 years of age consecutively diagnosed between March 1986 and June 1991 were followed prospectively for two years. The effect of age, gender and the presence of ketoacidosis (DKA) and islet-cell antibodies (ICA) on beta-cell function, metabolic control and insulin requirements were studied by multivariate analysis of variance (repeated measurements over time) in 90 patients who completed follow-up. DKA had an independent negative effect on residual beta-cell function over time (p = 0.001). ICA-positive patients had lower residual beta-cell function at the end of follow-up (p < 0.05), but overall differences were not significant. DKA and younger age had an independent negative influence on metabolic control (p < 0.05) and insulin requirements (p < 0.001) over time. It is concluded that residual beta-cell function in Type...
Islet transplantation is a promising treatment for diabetes mellitus, but current results are dis... more Islet transplantation is a promising treatment for diabetes mellitus, but current results are disappointing [1-4]. A crucial question determining the outcome of islet transplantation is beta-cell mass. The amount of transplanted tissue is essential in the evolution of the graft: a critical islet mass, higher than predicted [5], must be transplanted to achieve normoglycaemia [3, 6-9], and late failures [10] depend on the number of initially transplanted islets. In addition, the scarcity of islet tissue available for transplantation severely limits the number of transplants that can be performed. Therefore, it is important to identify ways to reduce the amount of islet tissue needed to achieve normoglycaemia after transplantation or to preserve the already transplanted islets. The detrimental effects of hyperglycaemia on transplanted islets have been previously reported,
We studied the effects of chronic hyperglycemia on beta-cell replication and mass in transplanted... more We studied the effects of chronic hyperglycemia on beta-cell replication and mass in transplanted (Tx) islets. Five groups of streptozocin-induced diabetic C57Bl/6 mice were transplanted with 100 (Tx-100) syngeneic islets, an insufficient beta-cell mass to restore normoglycemia. Groups 1 and 2 remained hyperglycemic throughout the study; after 30 days of hyperglycemia, a second transplantation of 250 islets (Tx-250) restored normoglycemia in groups 3, 4, and 5. Tx-250 was harvested on day 60 in all three groups, and transient mild hyperglycemia developed (10-12 days); thereafter, Tx-100 maintained blood glucose values in the normal range. Tx-100 was harvested 14 (group 1), 60 (groups 2 and 3), 74 (group 4), and 90 (group 5) days after transplantation. Hyperglycemia increased beta-cell replication after 14 days (group 1: 1.26 +/- 0.18%, P &amp;amp;lt; 0.05) but not after 60 days (group 2: 0.59 +/- 0.13%) compared with islets exposed to normoglycemia (group 3: 0.51 +/- 0.07%) (analysis of variance [ANOVA], P &amp;amp;lt; 0.0002). beta-cell replication in group 4 increased after Tx-250 harvesting (0.94 +/- 0.16%, P &amp;amp;lt; 0.05). The initially Tx beta-cell mass (0.21 +/- 0.014 mg) was progressively reduced in hyperglycemic groups (group 1: 0.13 +/- 0.020 mg; group 2: 0.048 +/- 0.012 mg; P &amp;amp;lt; 0.05) (ANOVA, P = 0.0001). Restoration of normoglycemia after Tx-250 did not modify beta-cell mass in Tx-100 grafts (group 3: 0.076 +/- 0.008 mg). However, after Tx-250 harvesting, beta-cell mass increased progressively (group 4: 0.11 +/- 0.018 mg; group 5: 0.14 +/- 0.026 mg, P &amp;amp;lt; 0.05), although it was still reduced compared with the initially Tx beta-cell mass (P &amp;amp;lt; 0.05). In summary, Tx islets exposed to severe chronic hyperglycemia showed a limited beta-cell replication and a progressive reduction in beta-cell mass. With normoglycemia, the Tx beta-cells recovered the replicative response to glucose and partially restored the initially Tx beta-cell mass, indicating that normoglycemia, even after long-term hyperglycemia, has a beneficial effect in islet transplantation.
We determined P-cell replication and mass in basal and stimulated conditions in long-term transpl... more We determined P-cell replication and mass in basal and stimulated conditions in long-term transplanted islets. Three groups of streptozocin-induced diabetic Lewis rats were transplanted with 1,000 islets (500 islets under left and right kidney capsules). At 2 (Tx-2), 5 (Tx-5), or 9 (Tx-9) months after transplantation, one of the two grafts (basal) was harvested; 14 days later, the contralateral graft (stimulated) was also harvested. Normoglycemia was achieved and maintained in all transplanted rats, although the capacity to respond to a glucose challenge deteriorated slightly 9 months after transplantation, p-cell replication remained stable in Tx-2, Tx-5, and Tx-9 basal grafts and was similar to replication in a control group of nontransplanted rats (0.28 ± 0.06%); replication increased in Tx-2 (0.90 ± 0.23%, P < 0.05) and Tx-9 (0.72 ± 0.09%, P < 0.05) stimulated grafts, p-cell mass in basal grafts was similar to the initially transplanted mass (1.24 ± 0.06 mg) and increased in stimulated grafts in Tx-2 (1.91 ± 0.38 mg, P < 0.05) and Tx-5 (1.73 ± 0.27 mg, P = 0.01) groups, compared with basal grafts, and in Tx-2 and Tx-9 groups (1.92 ± 0.30 mg, P < 0.05), compared with initially transplanted mass. Therefore, P-cell replication and mass were preserved up to 9 months after syngeneic transplantation, and pcells maintained the capacity to respond to increased metabolic demand, suggesting that replication is not a limiting factor in the survival of transplanted islets.
Lithium ion batteries are widely used in portable electronic devices and electric vehicles. Altho... more Lithium ion batteries are widely used in portable electronic devices and electric vehicles. Although battery technology has been significantly improved, it does not fully meet the energy requirements of electric vehicles. Electric vehicle batteries are built by serial and parallel connections of many cells to provide sufficient power. Differences between cells during battery usage can shorten the battery life and even worse can cause fire and explosion. Therefore, there is a need for a battery management system to ensure that the voltage, temperature and current information of the battery cells are used as optimum conditions. Cell balancing should be used to ensure that the battery cells are charging simultaneously. Cell voltage and temperature are measured by connecting auxiliary slave board to each series battery pack. This information is controlled by a master board. In this application, the excess energy is converted to heat by the load resistor on the utility boards. Fuzzy logic control is used to control the load resistor with the switching element. The charge status of the battery was estimated using the main battery current and the mains voltage with the master board. This application has been tested on an electric vehicle. A low cost modular battery management system has been developed that can control the safe charging and discharging of the vehicle battery.
Insulin-induced normoglycemia has shown to have a beneficial effect on the outcome of pancreatic ... more Insulin-induced normoglycemia has shown to have a beneficial effect on the outcome of pancreatic islets transplanted to diabetic recipients. The aim of the study was to identify the insulin treatment that can maximize its beneficial effect on islet transplants. Six groups of streptozotocin diabetic C57B1/6 mice were transplanted (Tx) with 100 syngeneic islets, an insufficient beta cell mass to restore normoglycemia, and were treated with insulin as follows: group 1 (n = 9): from day 10 before Tx to day 14 after Tx; group 2 (n = 11): from day 6 before Tx to Tx day; group 3 (n = 11): from Tx day to day 6 after Tx; group 4 (n = 7): from Tx day to day 14 after Tx; group 5 (n = 8): from day 10 to day 24 after Tx; group 6 (n = 18): Tx mice were not treated with insulin. Sixty days after Tx, normoglycemia was achieved in 100% of mice in groups 1, 4, and 5, in 73% of mice in group 2, and in only 45% and 33% of mice in groups 3 and 6, respectively (p < 0.01). Intraperitoneal glucose toler...
To determine the factors at diagnosis predictive of changes in residual beta-cell function and me... more To determine the factors at diagnosis predictive of changes in residual beta-cell function and metabolic control in Type 1 diabetes, 125 patients older than 7 years of age consecutively diagnosed between March 1986 and June 1991 were followed prospectively for two years. The effect of age, gender and the presence of ketoacidosis (DKA) and islet-cell antibodies (ICA) on beta-cell function, metabolic control and insulin requirements were studied by multivariate analysis of variance (repeated measurements over time) in 90 patients who completed follow-up. DKA had an independent negative effect on residual beta-cell function over time (p = 0.001). ICA-positive patients had lower residual beta-cell function at the end of follow-up (p < 0.05), but overall differences were not significant. DKA and younger age had an independent negative influence on metabolic control (p < 0.05) and insulin requirements (p < 0.001) over time. It is concluded that residual beta-cell function in Type...
Islet transplantation is a promising treatment for diabetes mellitus, but current results are dis... more Islet transplantation is a promising treatment for diabetes mellitus, but current results are disappointing [1-4]. A crucial question determining the outcome of islet transplantation is beta-cell mass. The amount of transplanted tissue is essential in the evolution of the graft: a critical islet mass, higher than predicted [5], must be transplanted to achieve normoglycaemia [3, 6-9], and late failures [10] depend on the number of initially transplanted islets. In addition, the scarcity of islet tissue available for transplantation severely limits the number of transplants that can be performed. Therefore, it is important to identify ways to reduce the amount of islet tissue needed to achieve normoglycaemia after transplantation or to preserve the already transplanted islets. The detrimental effects of hyperglycaemia on transplanted islets have been previously reported,
We studied the effects of chronic hyperglycemia on beta-cell replication and mass in transplanted... more We studied the effects of chronic hyperglycemia on beta-cell replication and mass in transplanted (Tx) islets. Five groups of streptozocin-induced diabetic C57Bl/6 mice were transplanted with 100 (Tx-100) syngeneic islets, an insufficient beta-cell mass to restore normoglycemia. Groups 1 and 2 remained hyperglycemic throughout the study; after 30 days of hyperglycemia, a second transplantation of 250 islets (Tx-250) restored normoglycemia in groups 3, 4, and 5. Tx-250 was harvested on day 60 in all three groups, and transient mild hyperglycemia developed (10-12 days); thereafter, Tx-100 maintained blood glucose values in the normal range. Tx-100 was harvested 14 (group 1), 60 (groups 2 and 3), 74 (group 4), and 90 (group 5) days after transplantation. Hyperglycemia increased beta-cell replication after 14 days (group 1: 1.26 +/- 0.18%, P &amp;amp;lt; 0.05) but not after 60 days (group 2: 0.59 +/- 0.13%) compared with islets exposed to normoglycemia (group 3: 0.51 +/- 0.07%) (analysis of variance [ANOVA], P &amp;amp;lt; 0.0002). beta-cell replication in group 4 increased after Tx-250 harvesting (0.94 +/- 0.16%, P &amp;amp;lt; 0.05). The initially Tx beta-cell mass (0.21 +/- 0.014 mg) was progressively reduced in hyperglycemic groups (group 1: 0.13 +/- 0.020 mg; group 2: 0.048 +/- 0.012 mg; P &amp;amp;lt; 0.05) (ANOVA, P = 0.0001). Restoration of normoglycemia after Tx-250 did not modify beta-cell mass in Tx-100 grafts (group 3: 0.076 +/- 0.008 mg). However, after Tx-250 harvesting, beta-cell mass increased progressively (group 4: 0.11 +/- 0.018 mg; group 5: 0.14 +/- 0.026 mg, P &amp;amp;lt; 0.05), although it was still reduced compared with the initially Tx beta-cell mass (P &amp;amp;lt; 0.05). In summary, Tx islets exposed to severe chronic hyperglycemia showed a limited beta-cell replication and a progressive reduction in beta-cell mass. With normoglycemia, the Tx beta-cells recovered the replicative response to glucose and partially restored the initially Tx beta-cell mass, indicating that normoglycemia, even after long-term hyperglycemia, has a beneficial effect in islet transplantation.
We determined P-cell replication and mass in basal and stimulated conditions in long-term transpl... more We determined P-cell replication and mass in basal and stimulated conditions in long-term transplanted islets. Three groups of streptozocin-induced diabetic Lewis rats were transplanted with 1,000 islets (500 islets under left and right kidney capsules). At 2 (Tx-2), 5 (Tx-5), or 9 (Tx-9) months after transplantation, one of the two grafts (basal) was harvested; 14 days later, the contralateral graft (stimulated) was also harvested. Normoglycemia was achieved and maintained in all transplanted rats, although the capacity to respond to a glucose challenge deteriorated slightly 9 months after transplantation, p-cell replication remained stable in Tx-2, Tx-5, and Tx-9 basal grafts and was similar to replication in a control group of nontransplanted rats (0.28 ± 0.06%); replication increased in Tx-2 (0.90 ± 0.23%, P < 0.05) and Tx-9 (0.72 ± 0.09%, P < 0.05) stimulated grafts, p-cell mass in basal grafts was similar to the initially transplanted mass (1.24 ± 0.06 mg) and increased in stimulated grafts in Tx-2 (1.91 ± 0.38 mg, P < 0.05) and Tx-5 (1.73 ± 0.27 mg, P = 0.01) groups, compared with basal grafts, and in Tx-2 and Tx-9 groups (1.92 ± 0.30 mg, P < 0.05), compared with initially transplanted mass. Therefore, P-cell replication and mass were preserved up to 9 months after syngeneic transplantation, and pcells maintained the capacity to respond to increased metabolic demand, suggesting that replication is not a limiting factor in the survival of transplanted islets.
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