Effects of L-theanine on intestinal morphology, barrier function, and MAPK signaling pathways in diquat-challenged piglets.

This study aimed to explore the protective effects of L-theanine supplementation on the diquat-challenged weaned piglets. A total of 160 weaned piglets were randomly divided into 4 groups using a 2 × 2 two-factor design, there were 4 replicates per group and 10 pigs per replicate. Piglets were fed diets (with 1000 mg/kg L-theanine addition or not), then challenged with diquat or saline on day 7. 21 days after challenge, two pigs from each replicate were selected for sample collection. Results showed that supplement with 1000 mg/kg L-theanine down-regulated the diarrhea rate, serum D-lactate level, tumor necrosis factor-α, and phosphorylation of extracellular regulated protein kinases (ERK1/2), p38 mitogen-activated protein kinase (MAPK), and c-Jun N-terminal kinase (JNK) signaling in pigs without diquat challenge (p < 0.05). While for diquat-challenged piglets, L-theanine addition increased average daily gain, jejunum villus height, and interferon-γ level (p < 0.05). Meanwhile, L-theanine addition decreased the diarrhea rates and mortality, serum D-lactate level, and phosphorylation of ERK and JNK in diquat-challenged pigs (p < 0.05). These results demonstrate that L-theanine pretreatment could alleviate diquat-induced oxidative stress and improve intestinal barrier function in diquat-challenged weaned piglets, which can be attributed to suppression of MAPK phosphorylation signaling pathways.

Fiber Mach-Zehnder-interferometer-based liquid crystal biosensor for detecting enzymatic reactions of penicillinase.

A novel, to the best of our knowledge, liquid crystal (LC) biosensor, based on an optical fiber Mach-Zehnder interferometer (MZI), is proposed. The proposed optical fiber MZI consists of two single-mode fibers and a tapered photonic crystal fiber (PCF). The PCF is coated with 4'-pentyl-biphenyl-4-carboxylic acid (PBA)-doped 4-cyano-4'-pentylbiphenyl (5CB). Being a pH-sensitive material, PBA can manipulate LC molecules to different orientations according to their pH values. When the orientation of LC molecules changes with varying pH, the effective refractive index of the cladding modes also is accordingly affected. Enzymatic reactions of penicillinase can release H+, which causes the decrease of the pH. Therefore, the enzymatic reactions of penicillinase can be sensed by monitoring the peak shift in the interference spectrum. The effects of the tapered diameter on the sensitivity of the sensor were experimentally investigated as well.

High Sensitivity Refractometer Based on a Tapered-Single Mode-No Core-Single Mode Fiber Structure.

We have proposed a novel tapered-single mode-no core-single mode (TSNS) fiber refractometer based on multimode interference. The TSNS structure exhibits a high contrast ratio (＞15 dB) and a uniform interference fringe. The influence of different lengths and diameters of the TSNS on the refractive index unit (RIU) sensitivity was investigated. The experimental investigations indicated a maximum sensitivity of 1517.28 nm/RIU for a refractive index of 1.417 and low-temperature sensitivity (＜10 pm/ºC). The experimental and simulation results are also in good agreement.