An analog fiber optic link developed for electrical pulse signal transmission.

The electromagnetic interference (EMI) around the devices for ionizing radiation experiments is a serious concern. In order to reduce EMI and enhance the signal-to-noise ratio, a new type of analog fiber optic link (FOL) has been developed for fast pulse signal transmission under complicated electromagnetic fields. Electrical signals are converted to optical signals through an electro-optical conversion process using the amplitude modulation mechanism. After long-distance transmission, optical signals can also be restored via photoelectric conversion. Each link has a transmitter unit connected via a fiber optic cable to the receiver unit. The transmitter unit consists of a distributed feedback laser, a driver circuit made of amplifiers, and an automatic temperature control module, while the receiver unit consists of a PIN detector, a transimpedance amplifier, a main amplifier, and a third order active low-pass filter. A prototype of this link has been fabricated and tested. The test results show that the transmission bandwidth of the analog signals is DC ∼ 155 MHz, the transmission delay is a typical 21 ns, the linear dynamic range is greater than 56 dB (692 times larger), the output noise is less than 4.5 mV, and the transmission distance is up to several kilometers, which can meet the requirements of ionizing radiation experiments. The FOL demonstrates great performance in transmission for scientific research with high quality in terms of transmission bandwidth, linearity, security, and stability.

ICOS/ICOSL upregulation mediates inflammatory response and endothelial dysfunction in type 2 diabetes mellitus.

OBJECTIVE: ICOS/ICOSL plays a crucial part in various disease-mediated immune responses. However, the exact role of ICOS/ICOSL in type 2 diabetes mellitus (T2DM) development remains unexplored. This study aims to investigate the role of ICOS/ICOSL in the pathogenesis of T2DM. MATERIALS AND METHODS: Human peripheral blood T-lymphocytes (CD3) and umbilical vein endothelial cells (HUVECs) were treated with high-glucose (HG) or advanced glycation end products (AGEs). A portion of CD3 cells was co-cultured with HUVECs and treated with different mediums or anti-ICOS mAbs. The ICOS/ICOSL and caspase-3 protein expression was measured by Western blotting. ELISA (enzyme-linked immunosorbent assay), MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), and NOx production assays were respectively used to detect cytokines level, cell viability and the production of NOx. RESULTS: HG and AGEs significantly upregulated ICOS/ICOSL expressions in T cells and HUVECs. T cell contact with HUVECs secreted more IFN-γ, IL-4, and IL-10 compared to non-contact cells, while cytokines from IL-6-, IL-1ß-, and CM- (the conditioned medium) treated cells did not differ from the control. A significant increase of IL-8 and IL-6 was found in HUVECs under both contact and non-contact conditions vs. control cells. Similar results were also observed in the comparison between CM1- (T cell condition medium) or CM2- (co-culture condition medium) treated cells and control cells. However, CM1 and CM2 treatment significantly inhibited cell viability and increased caspase-3 and NOx production; blocking ICOS/ICOSL remarkably decreased cytokines secretion, enhanced cell viability and reduced caspase-3 and NOx production. CONCLUSIONS: HG and AGEs cause T cell inflammatory response and vascular endothelial dysfunction by upregulating ICOS/ICOSL, which may be one of the possible mechanisms of cardiovascular complications development in T2DM patients.

Effect of siglidine on glucose lipid metabolism and the expression of iNOS and GLP-1 receptors in diabetic rats.

OBJECTIVE: Diabetic nephropathy (DN) has become the major complication of diabetes. The progression of the disease impedes the efficacy of DN treatment. Therefore, the strategies to inhibit or reverse kidney damage in DN patients are of critical importance. We aim to investigate the effect of sitagliptin on DN within rat model and analyze the associated metabolism and expression of iNOS/GLP-1 receptor. MATERIALS AND METHODS: Diabetic model was generated by using Sprague-Dawley (SD) rats, which received an intra-peritoneal injection of 30 mg/kg streptozotocin. Rats were then treated with saline or 15 mg/(kg.d) sitagliptin by gavage. After 12 weeks, fasting blood glucose and insulin resistance were measured. Rat glucose and lipid metabolism were evaluated by high triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C). Western blot was used to measure expression of glucose-6-phosphatase (G6Pase), phosphoenolpyruvate carboxykinase (PEPCK), fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC) related with glucose-lipid metabolism, and expression of iNOS and GLP-1 expression in kidney tissues. RESULTS: After 12 weeks of feeding, the levels of blood glucose and lipid in sitagliptin group were significantly decreased compared to those in control group (p<0.05), whilst insulin sensitivity was enhanced (p<0.05). Western blot showed that sitagliptin downregulated the expressions of glucose-lipid metabolism proteins such as G6Pase, PEPCK, ACC and FAS in rat livers, inhibited iNOS expression in kidneys and elevated GLP-1 receptor activity (p<0.05). CONCLUSIONS: Sitagliptin effectively stabilizes blood glucose and lipid levels in DN rats, significantly improves glucose-lipid metabolism and protects kidney and vascular endothelial cells during DN pathogenesis through inhibiting iNOS expression and elevating GLP-1 receptor activity.