The Roles of Polyamines in Intestinal Development and Function in Piglets.

The gastrointestinal tract plays crucial roles in the digestion and absorption of nutrients, as well as in maintenance of a functional barrier. The development and maturation of the intestine is important for piglets to maintain optimal growth and health. Polyamines are necessary for the proliferation and growth of enterocytes, which play a key role in differentiation, migration, remodeling and integrity of the intestinal mucosa after injury. This review elaborates the development of the structure and function of the intestine of piglets during embryonic, suckling and weaning periods, the utilization and metabolism of polyamines in the intestine, as well as the role of polyamines in intestinal development and mucosal repair. The nutritional intervention to improve intestinal development and functions by modulating polyamine metabolism in piglets is also put forward. These results may help to promote the adaption to weaning in pigs and provide useful information for the development and health of piglets.

Dietary Chito-oligosaccharide attenuates LPS-challenged intestinal inflammation via regulating mitochondrial apoptotic and MAPK signaling pathway.

To investigate the regulatory effects of Chito-oligosaccharide (COS) on the anti-oxidative, anti-inflammatory, and MAPK signaling pathways. A total of 40 28-day-old weaned piglets were randomly allotted to 4 equal groups [including the control group, lipopolysaccharide (LPS) group, COS group, and COS*LPS group]. On the morning of d 14 and 21, piglets were injected with saline or LPS. At 2 h post-injection, whole blood samples were collected on d 14 and 21, and small intestine and liver samples were collected and analyzed on d 21. The results showed that COS inhibited the LPS-induced increase of malondialdehyde (MDA) concentration and hepatic TNF-α cytokines. COS significantly increased the serum total antioxidant capability (T-AOC) value on d 14, and total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-PX) activities in both serum and liver on d 21. Furthermore, it increased hepatic catalase (CAT) activity. COS also increased the LPS-induced decrease in serum IgG concentrations. Immunohistochemical analysis results showed that COS significantly increased the jejunal and ileal Caspase 3, and ileal CD4+ values challenged by LPS. Dietary COS decreased the LPS-induced jejunal and ileal BAX and CCL2 mRNA levels, markedly decreased ileal COX2 and SOD1 mRNA levels, while increasing ileal iNOS. Furthermore, COS significantly increased the LPS-induced jejunal and ileal p-P38 and MyD88, as well as jejunal P38, while it effectively suppressed jejunal JNK1, and jejunal and ileal JNK2, p-JNK1, and p-JNK2 protein expressions. These results demonstrated that COS could be beneficial by attenuating LPS-challenged intestinal inflammation via regulating mitochondrial apoptotic and MAPK signaling pathways.

Influences of focusing conditions on optical poling in lithium niobate using a 1035 nm femtosecond fiber laser.

In this study, we demonstrate the optical induction of ferroelectric domain inversion on the -z surface of lithium niobate crystals using a 1035 nm femtosecond fiber laser. We investigate the effects of laser power and focusing parameters on domain morphology. The results revealed that domains exhibit an irregular random distribution at low power, whereas regularly arranged domains were formed near the crystal damage threshold. Furthermore, with sufficiently high power, lens focusing enables the fabrication of uniformly sized domains exceeding 100 µm. The results suggest potential applications for controlling domain morphology and the duty cycle, and fabricating ferroelectric functional devices.

Oxygen and Titanium Vacancies in a BiOBr/MXene-Ti3C2 Composite for Boosting Photocatalytic N2 Fixation.

Solar energy can be used as "green" energy by photocatalysis for the nitrogen fixation under the atmospheric conditions compared with the traditional energy-intensive industrial production of ammonia. However, the complex kinetics and high reaction barriers greatly hinder the development of the photocatalytic N2 reduction reaction. Herein, a BiOBr/MXene-Ti3C2 composite catalyst is prepared by the simple electrostatic adsorption and self-assembly method. The as-prepared 10 wt % BiOBr/Ti3C2 exhibits the best performance for N2 fixation to NH3 by photocatalysis. The evolution rate of NH3 is up to 234.6 µmol·g-1·h-1, which is approximately 48.8 times and 52.4 times higher than those of pure BiOBr and Ti3C2, respectively. It is found that the designed double vacancies of oxygen and titanium for BiOBr/Ti3C2 composites, with the availability of localized electrons, have the ability to adsorb and activate N2, which can be efficiently reduced to NH3 by the interfacial electrons transferred from the excited BiOBr/Ti3C2 composite. In addition, the results of in situ Fourier transform infrared show the generation of NxHy species by the continuous protonation processes. Moreover, titanium vacancy (VTi) induces a strong absorption energy for nitrogen atoms on the surface of BiOBr/Ti3C2 according to the density functional theory calculations. In particular, the P-electron feedback caused by VTi could effectively promote the weakening of the N≡N triple bond and elongate the N2 bond length by ∼31.6%. This work might provide new insights into the synergistic effect of double defects and inspiration for the rational design of catalysts by defect engineering in the field of catalytic synthesis of ammonia.

Construction of Bi2O2CO3/Ti3C2 heterojunctions for enhancing the visible-light photocatalytic activity of tetracycline degradation.

Bi2O2CO3 (BOC) was successfully loaded on a highly conductive Ti3C2 surface by the hydrothermal method, forming a unique BOC/Ti3C2 heterostructure. The use of advanced characterization methods reveals the composition, morphology and photoelectric properties of the material. The results show that the interface formed by close contact between BOC and Ti3C2 provides an effective channel for charge transfer between the two. Importantly, the photocatalytic degradation efficiency of BOC/Ti3C2 for tetracycline (TC) is ~80%, which is significantly higher than the degradation efficiency of pure BOC and pure Ti3C2 for TC. In addition, BOC/Ti3C2 still has high catalytic activity in the degradation of complex mixed antibiotics. This is because BOC and Ti3C2 have large specific surface areas, high light absorption capacity and efficient carrier separation after recombination. At the same time, the detected superoxide radicals (O2-) and holes (h+) are the main active substances. The degradation pathway and catalytic mechanism of the photocatalytic degradation of TC by BOC/Ti3C2 are further explained. This research designed and developed a BOC/Ti3C2 composite material for the photocatalytic degradation of tetracycline and mixed antibiotic wastewater, providing experimental methods and ideas for actual wastewater treatment.

Fabrication of novel CuFe2O4/MXene hierarchical heterostructures for enhanced photocatalytic degradation of sulfonamides under visible light.

The overuse of sulfonamides, causing serious pollution of water bodies, has drawn great attention from society. To address these problems, a novel CuFe2O4/MXene (CFO/Ti3C2) heterojunction photocatalyst was used to photodegrade the antibiotic sulfamethazine (SMZ, a typical pollutant) under visible light, and the synergy and coupling function of the two components in the heterojunction system were analyzed. With the aid of time-resolved photoluminescence (TRPL) and transient surface photovoltage (TPV) spectra, the carrier lifetimes and kinetic behaviors were studied, revealing that the lifetime of photoinduced carriers was prolonged by loading Ti3C2, inhibiting the reorganization of photogenerated electron holes. More importantly, the organic intermediates and mineralization degree were identified by high-performance liquid chromatography (HPLC)-mass spectrometry (MS) and total organic carbon (TOC) techniques. The results show that the breaking of SN bonds, the oxidation of aniline and deamination were dominated by the attack of •OH. This work shows a new model for the degradation mechanism of SMZ over CFO/MXene heterostructures.

The Role of Nrf2 Signaling Pathway in Eucommia ulmoides Flavones Regulating Oxidative Stress in the Intestine of Piglets.

Eucommia ulmoides flavones (EUF) have been demonstrated to alleviate oxidative stress and intestinal damage in piglets, but their effect target is still poorly understood. NF-E2-related factor 2 (Nrf2) pathway plays a very important role in the defense mechanism. This study was designed to investigate the regulation of EUF on the Nrf2 pathway and inhibition of Nrf2 on oxidative stress in the intestine of piglets. An in vivo study was conducted in weaned piglets treated with basal diet, basal diet+diquat, and 100 mg/kg EUF diet+diquat for 14 d to determine Nrf2 and Keap1 protein expressions, as well as downstream antioxidant gene mRNA expression. An in vitro study was performed in a porcine jejunal epithelial cell line to investigate the effect of inhibiting Nrf2 on cell growth and intracellular oxidative stress parameters. The results showed that the supplementation of EUF decreased the oxidized glutathione (GSSG) concentration and the ratio of GSSG to glutathione (GSH) but increased the protein expressions of nuclear Nrf2 and Kelch-like ECH-associated protein 1 (Keap1) as well as mRNA expression of heme oxygenase 1 (HO-1), NAD(P)H:quinone oxidoreductase 1 (NQO-1), and glutamate cysteine ligase catalytic subunit (GCLC) in the small intestinal mucosa of diquat-challenged piglets. When Nrf2 was inhibited by using ML385, cell viability, cellular antioxidant activities, expressions of nuclear Nrf2 and Keap1 protein, and downstream antioxidant enzyme (HO-1, NQO-1, and GCLC) mRNA were decreased in paraquat-treated enterocytes. These results showed that the Nrf2 signaling pathway played an important role in EUF-regulating oxidative stress in the intestine of piglets.