Hydrogeochemical characterization, quality assessment, and potential nitrate health risk of shallow groundwater in Dongwen River Basin, North China.

Assessing groundwater geochemical formation processes and pollution circumstances is significant for sustainable watershed management. In the present study, 58 shallow groundwater samples were taken from the Dongwen River Basin (DRB) to comprehensively assess the hydrochemical sources, groundwater quality status, and potential risks of NO3- to human health. Based on the Box and Whisker plot, the cation's concentration followed the order of Ca2+ > Mg2+ > Na+ > K+, while anions' mean levels were HCO3- > SO42- > NO3- > Cl-. The NO3- level in groundwater samples fluctuated between 4.2 and 301.3 mg/L, with 67.2% of samples beyond the World Health Organization (WHO) criteria (50 mg/L) for drinking. The Piper diagram indicated the hydrochemical type of groundwater and surface water were characterized as Ca·Mg-HCO3 type. Combining ionic ratio analysis with principal component analysis (PCA) results, agricultural activities contributed a significant effect on groundwater NO3-, with soil nitrogen input and manure/sewage inputs also potential sources. However, geogenic processes (e.g., carbonates and evaporite dissolution/precipitation) controlled other ion compositions in the study area. The groundwater samples with higher NO3- values were mainly found in river valley regions with intense anthropogenic activities. The entropy weight water quality index (EWQI) model identified that the groundwater quality rank ranged from excellent (70.7%) and good (25.9%) to medium (3.4%). However, the hazard quotient (HQ) used in the human health risk assessment (HHRA) model showed that above 91.38% of groundwater samples have a NO3- non-carcinogenic health risk for infants, 84.48% for children, 82.76% for females, and 72.41% for males. The findings of this study could provide a scientific basis for the rational development and usage of groundwater resources as well as for the preservation of the inhabitants' health in DRB.

Synthesis, characterization and crystallization kinetics of a bio-based, heat-resistance nylon 5T/10T.

The rapid consumption of fossil resources and its adverse impact on the environment require the use of bio-based materials to replace petrochemical products. In this study, we present a bio-based, heat-resistant engineering plastic, poly(pentamethylene terephthalamide) (nylon 5T). To address the issues of the narrow processing window and difficulty in melting processing of nylon 5T, we introduced more flexible decamethylene terephthalamide (10T) units to create a copolymer, nylon 5T/10T. The chemical structure was confirmed by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (13C-NMR). We investigated the influence of 10T units on the thermal performance, crystallization kinetics, crystallization activation energy, and crystal structures of the copolymers. Our results demonstrate that the crystal growth mode of nylon 5T is a two-dimensional discoid growth pattern, while nylon 5T/10T exhibits a two-dimensional discoid or three-dimensional spherical growth pattern. The melting temperature, crystallization temperature, and crystallization rate first decrease and then increase, and crystal activation energy first increases and then decreases as a function of 10T units. These effects are attributed to the combined impact of molecular chain structure and polymer crystalline region. Bio-based nylon 5T/10T shows excellent heat resistance (melting temperature > 280 °C) and a wider processing window than nylon 5T and 10T, which is a promising heat-resistant engineering plastic.

L-Methionine inhibits 4-hydroxy-2-nonenal accumulation and suppresses inflammation in growing rats.

BACKGROUND/OBJECTIVES: 4-Hydroxy-2-nonenal (HNE) is a biomarker for oxidative stress to induce inflammation. Methionine is an essential sulfur-containing amino acid with antioxidative activity. On the other hand, the evidence on whether and how methionine can depress HNE-derived inflammation is lacking. In particular, the link between the regulation of the nuclear factor-κB (NF-κB) signaling pathway and methionine intake is unclear. This study examined the link between depression from HNE accumulation and the anti-inflammatory function of L-methionine in rats. MATERIALS/METHODS: Male Wistar rats (3-week-old, weighing 70-80 g) were administered different levels of L-methionine orally at 215.0, 268.8, 322.5, and 430.0 mg/kg body weight for two weeks. The control group was fed commercial pellets. The hepatic HNE contents and the protein expression and mRNA levels of the inflammatory mediators were measured. The interleukin-10 (IL-10) and glutathione S-transferase (GST) levels were also estimated. RESULTS: Compared to the control group, hepatic HNE levels were reduced significantly in all groups fed L-methionine, which were attributed to the stimulation of GST by L-methionine. With decreasing HNE levels, L-methionine inhibited the activation of NF-κB by up-regulating inhibitory κBα and depressing phosphoinositide 3 kinase/protein kinase B. The mRNA levels of the inflammatory mediators (cyclooxygenase-2, interleukin-1ß, interleukin-6, inducible nitric oxide synthase, tumor necrotic factor alpha) were decreased significantly by L-methionine. In contrast, the protein expression of these inflammatory mediators was effectively down regulated by L-methionine. The anti-inflammatory action of L-methionine was also reflected by the up-regulation of IL-10. CONCLUSIONS: This study revealed a link between the inhibition of HNE accumulation and the depression of inflammation in growing rats, which was attributed to L-methionine availability. The anti-inflammatory mechanism exerted by L-methionine was to inhibit NF-κB activation and to up-regulate GST.

Methionine strengthens anti-inflammation of rice protein via depressing NF-κB activation and stimulating Msr expression in rats fed cholesterol-enriched diets.

Oxidized low-density lipoprotein (ox-LDL) is an inducer of inflammation. To elucidate the link of depression of ox-LDL accumulation and anti-inflammatory function of rice protein (RP) whether dependent on methionine availability, growing and adult rats were fed RP and methionine-supplemented RP (RM) under cholesterol-enriched dietary condition. After two weeks feeding, RP and RMs exerted the anti-inflammatory effects through up-regulating IL-10, while RP and RMs significantly reduced ox-LDL levels and effectively suppressed the expressions of inflammatory mediators (COX-2, IL-1ß, IL-6, TNF-α, iNOS). The anti-inflammatory molecular mechanism was to inhibit NF-κB activation and to simulate methionine sulfoxide reductase expression. Results showed, under cholesterol-enriched dietary condition, the anti-inflammatory action can be induced by RP and enhanced by methionine in growing and adult rats. The present study reveals a link of the decreased ox-LDL accumulation with the anti-inflammatory function of RP, which is dependent on methionine availability and independent of dietary cholesterol.

Impact of Low-Temperature Storage on the Microstructure, Digestibility, and Absorption Capacity of Cooked Rice.

This study examined the effects of low-temperature storage on the microstructural, absorptive, and digestive properties of cooked rice. Cooked rice was refrigerated and stored at 4 °C for 0.5, 1, 3, 5, and 7 days, as well as frozen and preserved at -20, -40, and -80 °C for 0.5, 1, 3, 5, 7, 14, 21, and 28 days. The results indicated that the stored rice samples generally exhibited a higher absorption capacity for oil, cholesterol, and glucose than the freshly cooked rice. In addition, after storage, the digestibility of the cooked rice declined, namely, the rapidly digestible starch (RDS) content and estimated glycemic index (eGI) decreased, whereas the slowly digestible starch (SDS) and resistant starch (RS) content increased. Moreover, the increment of the storage temperatures or the extension of storage periods led to a lower amylolysis efficiency. Scanning electron microscopy (SEM) analysis indicated that storage temperature and duration could effectively modify the micromorphology of the stored rice samples and their digestion. Moreover, microstructural differences after storage and during simulated intestinal digestion could be correlated to the variations in the absorption capacity and digestibility. The findings from this study will be useful in providing alternative storage procedures to prepare rice products with improved nutritional qualities and functional properties.

Rice protein suppresses 4-hydroxy-2-nonenal-induced inflammation owing to methionine availability.

4-Hydroxy-2-nonenal (HNE) is one of the most important products of lipid peroxidation, which induces inflammation. To investigate the effects of rice protein (RP) on suppressing HNE-induced inflammation and the role of methionine in regulating the anti-inflammatory function of RP, Wistar rats (male, weighing 180-200 g) were either ad libitum fed a pellet diet with oral administration of methionine or ad libitum fed RP for 2 weeks. RP and methionine significantly reduced HNE levels and effectively suppressed the expressions of cyclooxygenase-2, tumor necrosis factor alpha, interleukin-1ß (IL-1ß) and IL-6, and inducible nitric oxide synthase. The anti-inflammatory action of RP was evident from the upregulation of IL-10 and glutathione S-transferase (GST), which played a role in the detoxification of HNE. The results show that the molecular mechanism responsible for the anti-inflammatory function of RP is the inhibition of nuclear factor kappa B (NF-κB) activation by the downregulation of protein kinase B/phosphoinositide 3 kinase. Further, this study demonstrates that Met availability contributes to the suppression of HNE-induced inflammation through upregulating IL-10 and GST in rats fed RP. Novelty: RP suppresses HNE-induced inflammation. Methionine plays a role in upregulating IL-10 and GST. Methionine availability regulates the inhibition of NF-κB by RP.

l-Arginine prevents 4-hydroxy-2-nonenal accumulation and depresses inflammation via inhibiting NF-κB activation.

4-Hydroxy-2-nonenal (HNE) is an inducer of inflammation. The aim of this study was to elicit the link between the inhibition of HNE accumulation and the depression of inflammation whether dependent onl-arginine availability in growing rats. Male Wistar rats were fed with different levels of l-arginine at 250, 500, and 1000 mg/kg body weight for 14 days. The control group was fed with commercial pellets. After 14 days of oral administration, l-arginine significantly reduced hepatic accumulation of HNE and depressed inflammation in rats as compared with the control group. Compared to the control group, the anti-inflammatory action of l-arginine is reflected by upregulation of hepatic interleukin-10 (IL-10) and the suppression of hepatic cyclooxygenase-2, tumor necrotic factor α, IL-1ß, and IL-6 expressions in growing rats. With l-arginine administration, the activation of nuclear factor-κB (NF-κB) was efficaciously inhibited through the upregulation of inhibitory κBα, and the depression of phosphoinositide 3-kinase/protein kinase B (PI3K/Akt). In conclusion, this study demonstrated that l-arginine could reduce hepatic HNE levels and depress inflammation in growing rats, revealing a link between the inhibition of HNE accumulation with the depression of inflammation, which was attributed to the availability of l-arginine. A significant finding of this study was that the anti-inflammatory mechanism exerted by l-arginine was to inhibit NF-κB activation via downregulating PI3K/Akt.

Non-isothermal crystallization, yellowing resistance and mechanical properties of heat-resistant nylon 10T/66/titania dioxide/glass fibre composites.

Herein, we report novel heat-resistant nylon 10T/66/titania dioxide/glass fibre (nylon 10T/66/TiO2/GF) composites based on as-synthesised nylon 10T/66, which is a copolymer of poly(decamethylene terephthalamide) (nylon 10T). The non-isothermal crystallization behaviors of nylon 10T/66 and nylon 10T/66/TiO2/GF composites were investigated by differential scanning calorimetry (DSC). Jeziorny and Mo equations were used to analyse the crystallization kinetics, whereas the Kissinger method was applied to calculate the activation energy. It turned out that the introduction of TiO2 and GF could accelerate the crystallization of nylon 10T/66 and exhibited an effective heterogeneous nucleation effect. In addition, we conducted yellowing resistance and mechanical property analysis of the nylon 10T/66/TiO2/GF composites. The above results successfully demonstrated that the heat-resistant nylon 10T/66/TiO2/GF composites possess higher crystallization temperature and crystallization rate, whiter color, and better yellowing resistance and mechanical properties than previously as-synthesised nylon 10T/66. Consequently, nylon 10T/66/TiO2/GF composites have great potential to be used as a heat-resistant engineering plastic.

Synthesis, characterization and thermal decomposition kinetics of a bio-based transparent nylon 10I/10T.

Herein, we report a novel transparent engineering plastic nylon 10I/10T based on bio-based poly(decamethylene isophthalamide) (nylon10I). We have demonstrated the one-step melt polycondensation synthesis of transparent nylon and carried out Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance (1H NMR) to confirm the chemical structure. Furthermore, the dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) were used to analyze the thermal properties. Glass transition temperature (Tg ) and thermal decomposition onset temperature (T1 ) of nylon 10I/10T (15 wt. % 10T) were 118.9 and 438.0 °C, respectively. The intrinsic viscosity, water absorption, light transmittance, mechanical properties, solvent resistance and the decomposition mechanism of nylon 10I/10T have also been investigated. The results show that the nylon 10I/10T has lower water absorption and enhanced solvent resistance compared to nylon 6-3-T, which indicates that nylon 10I/10T is a promising transparent plastic.