Elimination of the chirp of optical pulses through cascaded nonlinearities in periodically poled lithium niobate waveguides

We propose and demonstrate a novel method for the elimination of arbitrary frequency chirp from short optical pulses. The technique is based on the combination of two cascaded second-order nonlinearities in two individual periodically poled lithium niobate waveguides

Functional modulation of AMP-activated protein kinase by cereblon

AbstractMutations in cereblon (CRBN), a substrate binding component of the E3 ubiquitin ligase complex, cause a form of mental retardation in humans. However, the cellular proteins that interact with CRBN remain largely unknown. Here, we report that CRBN directly interacts with the α1 subunit of AMP-activated protein kinase (AMPK α1) and inhibits the activation of AMPK activation. The ectopic expression of CRBN reduces phosphorylation of AMPK α1 and, thus, inhibits the enzyme in a nutrient-independent manner. Moreover, AMPK α1 can be potently activated by suppressing endogenous CRBN using CRBN-specific small hairpin RNAs. Thus, CRBN may act as a negative modulator of the AMPK signaling pathway in vivo

Axial strain dependence of all-fiber acousto-optic tunable filters

We report the axial strain dependence of two types of all-fiber acousto-optic tunable filters based on flexural and torsional acoustic waves. Experimental observation of the resonant wavelength shift under applied axial strain could be explained by theoretical consideration of the combination of acoustic and optical effects. We discuss the possibility of suppressing the strain effect in the filters, or conversely, the possibility of using the strain dependence for wavelength tuning or strain sensors

Effect of Long-Term Dietary Arginyl-Fructose (AF) on Hyperglycemia and HbA1c in Diabetic db/db Mice

We have previously reported that Amadori compounds exert anti-diabetic effects by lowering sucrose-induced hyperglycemia in normal Sprague-Dawley rats. In the present study we extended our recent findings to evaluate whether α-glucosidase inhibitor arginyl-fructose (AF) lowers blood glucose level in diabetic db/db mice, a genetic model for type 2 diabetes. The db/db mice were randomly assigned to high-carbohydrate diets (66.1% corn starch) with and without AF (4% in the diet) for 6 weeks. Changes in body weight, blood glucose level, and food intake were measured daily for 42 days. Dietary supplementation of AF resulted in a significant decrease of blood glucose level (p \u3c 0.001) and body weight (p \u3c 0.001). The level of HbA1c, a better indicator of plasma glucose concentration over prolonged periods of time, was also significantly decreased for 6-week period (p \u3c 0.001). Dietary treatment of acarbose® (0.04% in diet), a positive control, also significantly alleviated the level of blood glucose, HbA1c, and body weight. These results indicate that AF Maillard reaction product improves postprandial hyperglycemia by suppressing glucose absorption as well as decreasing HbA1c level

Effect of Long-Term Dietary Arginyl-Fructose (AF) on Hyperglycemia and HbA1c in Diabetic \u3cem\u3edb/db\u3c/em\u3e Mice

We have previously reported that Amadori compounds exert anti-diabetic effects by lowering sucrose-induced hyperglycemia in normal Sprague-Dawley rats. In the present study we extended our recent findings to evaluate whether α-glucosidase inhibitor arginyl-fructose (AF) lowers blood glucose level in diabetic db/db mice, a genetic model for type 2 diabetes. The db/db mice were randomly assigned to high-carbohydrate diets (66.1% corn starch) with and without AF (4% in the diet) for 6 weeks. Changes in body weight, blood glucose level, and food intake were measured daily for 42 days. Dietary supplementation of AF resulted in a significant decrease of blood glucose level (p \u3c 0.001) and body weight (p \u3c 0.001). The level of HbA1c, a better indicator of plasma glucose concentration over prolonged periods of time, was also significantly decreased for 6-week period (p \u3c 0.001). Dietary treatment of acarbose® (0.04% in diet), a positive control, also significantly alleviated the level of blood glucose, HbA1c, and body weight. These results indicate that AF Maillard reaction product improves postprandial hyperglycemia by suppressing glucose absorption as well as decreasing HbA1c level

In situ formation of silk-gelatin hybrid hydrogels for affinity-based growth factor sequestration and release

Silk fibroin (SF) and gelatin are natural polymers suitable for biomedical applications, including controlled protein release. SF offers high mechanical strength and slow enzymatic degradability, whereas gelatin contains bioactive motifs that can provide biomimicry to the resulting scaffolds. Owing to their complementary material properties, SF and gelatin are increasingly being used together to afford hybrid scaffolds with adjustable properties. Here, we report the use of in situ crosslinked SF/gelatin hydrogels as a platform for tunable growth factor sequestration and delivery. We demonstrate that the physical assembly of SF into insoluble networks could be accelerated by sonication even in the presence of gelatin. However, the processing conditions from which to prepare SF aqueous solution (e.g., heating duration and number of processing steps) drastically altered the resulting hydrogel physical properties. Furthermore, the stiffness of SF/gelatin hybrid gels displayed temperature dependency. Specifically, incorporation of gelatin increased gel stiffness at 25 °C but decreases hydrogel mechanical stability at 37 °C. The thermostability of SF/gelatin gels can be restored by using a low concentration of genipin, a naturally derived chemical crosslinker. We also incorporate heparin-conjugated gelatin (GH) into the hydrogels to create a hybrid matrix capable of sequestering growth factors, such as basic fibroblast growth factor (bFGF). Both sonicated SF (SSF) and hybrid SSF-GH gels exhibit moderate bFGF sequestration, but only SSF-GH gels afford slow release of bFGF. On the other hand, genipin-stabilized network exhibited the highest retention and sustained release of bFGF, suggesting the suitability of this particular formulation as a scaffold for tissue engineering applications