Effect of Wet-Dry Cycling on Properties of Natural-Cellulose-Fiber-Reinforced Geopolymers: A Short Review.

To study the long-term properties of cement-based and geopolymer materials exposed to outdoor environments, wet-dry cycles are usually used to accelerate their aging. The wet-dry cycling can simulate the effects of environmental factors on the long-term properties of the composites under natural conditions. Nowadays, the long-term properties of geopolymer materials are studied increasingly deeply. Unlike cement-based materials, geopolymers have better long-term properties due to their high early strength, fast hardening rate, and wide range of raw material sources. At the same time, natural cellulose fibers (NCFs) have the characteristics of abundant raw materials, low price, low carbon, and environmental protection. The use of NCFs as reinforcements of geopolymer matrix materials meets the requirements of sustainable development. In this paper, the types and properties of NCFs commonly used for geopolymer reinforcement and the polymerization mechanism of geopolymer matrix materials are summarized. By analyzing the properties of natural-cellulose-fiber-reinforced geopolymers (NCFRGs) under non-wet-dry cycles and NCFRGs under wet-dry cycles, the factors affecting the long-term properties of NCFRGs under wet-dry cycles are identified. Meanwhile, the degradation mechanism and mechanical properties of NCFRG composites after wet-dry cycles are analyzed. In addition, the relationship between the properties of composites and the change of microstructure of fiber degradation is further analyzed according to the results of microscopic analysis. Finally, the effects of wet-dry cycles on the properties of fibers and geopolymers are obtained.

Clinical efficacy of Huanglian Wendan decoction in treating type 2 diabetes mellitus: A systematic review and meta-analysis.

BACKGROUND: Huanglian Wendan decoction (HLWDD) is a traditional Chinese prescription, which has been used to treat type 2 diabetes mellitus (T2DM) in recent years. However, no studies have evaluated its underlying clinical efficacy. Therefore, we used systematic review and meta-analysis to explore the clinical efficacy of HLWDD in treating T2DM. METHODS: The randomized controlled trials of HLWDD on T2DM were retrieved from Chinese and foreign databases. The primary outcomes included fasting blood glucose (FBG), 2-hour postprandial blood glucose (2hPG), and glycosylated hemoglobin, type A1c (HbA1c). The secondary outcomes included fasting serum insulin, homeostasis model assessment of insulin resistance (HOMA-IR), total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-c), and high-density lipoprotein cholesterol (HDL-c). Statistical analyses were performed using Review Manager and Stata software. Mean difference (MD) with 95% confidence intervals (CI) were used to describe results. The grades of recommendation assessment, development and evaluation approach was used to rate the quality of the evidence; and trial sequential analysis was used to evaluate the required information size and treatment benefits. RESULTS: Twenty-three randomized controlled trials were included in this study. We showed that HLWDD can improve FBG (MD = -0.99, 95% CI: -1.10 to -0.88), 2hPG (MD = -1.57, 95% CI: -1.97 to -1.17), HbA1c (MD = -1.11, 95% CI: -1.42 to -0.80), HOMA-IR (MD = -0.80, 95% CI: -1.80 to -0.51), TC (MD = -0.65, 95% CI: -0.88 to -0.42), TG (MD = -0.32, 95% CI: -0.38 to -0.27), LDL-c (MD = -0.54, 95% CI: -0.66 to -0.41), and HDL-c (MD = 0.08, 95% CI: 0.02-0.15) levels in T2DM patients. Trial sequential analysis suggested that the eficacy of HLWDD in improving FBG, 2hPG, HbA1c, HOMA-IR, TC, TG, LDL-c, and HDL-c was sufficient to draw a firm conclusion. Grades of recommendation assessment showed that HLWDD only has high or moderate quality of evidence in improving FBG, and TG. CONCLUSION: HLWDD can improve blood glucose and blood lipid levels in T2DM patients, and may be a potential drug to treat T2DM.

Analyses of Physical and Chemical Compositions of Different Medicinal Specifications of CRPV by Use of Multiple Instrumental Techniques Combined with Multivariate Statistical Analysis.

Citri Reticulatae Pericarpium Viride (CRPV) is the processed product of Citrus reticulata Blanco. We systematically analyzed two CRPV types, Geqingpi (GQP) and Sihuaqingpi (SHQP), based on powder color, microscopic characteristics, and chemical composition. In addition, we characterized their constituents via ultra-high-performance liquid chromatography with hybrid quadrupole-orbitrap mass spectrometry (UHPLC-Q-Exactive Orbitrap-MS). Both showed significant differences in their powder color and microscopic characteristics. Fourier-transform infrared (FT-IR) spectroscopic analysis results showed that the C=O peak absorption of carboxylic acids and their carbonyl esters in SHQP was higher than that of GQP, while the C-OH and C-H plane bending peaks of polysaccharides were lower than those of GQP. We analyzed these data via similarity analysis, PCA, and OPLS-DA. GQP and SHQP had large distinct differences. Based on the mass measurements for molecular and characteristic fragment ions, we identified 44 main constituents from CRPV, including different flavonoid glycosides and flavonoid aglycones in SHQP and GQP, respectively. We found luteolin-6-C-glucoside, orientin, rhoifolin, and pilloin solely in SHQP, and naringenin and hesperetin only in GQP. The peak area measurements showed GQP having a higher flavonoid glycoside (narirutin, hesperidin, etc.) content, whereas SHQP had a higher polymethoxyflavone (nobiletin, tangeretin, etc.) content. Since we holistically analyzed two CRPV types, the results can not only support future pharmacological research, but also provide a scientific basis for formulating more reasonable CRPV quality standards and guide its clinical potential as a precision medicine.

Latitudinal shifts of soil microbial biomass seasonality.

Soil microbes ultimately drive the mineralization of soil organic carbon and thus ecosystem functions. We compiled a dataset of the seasonality of microbial biomass carbon (MBC) and developed a semi-mechanistic model to map monthly MBC across the globe. MBC exhibits an equatorially symmetric seasonality between the Northern and Southern Hemispheres. In the Northern Hemisphere, MBC peaks in autumn and is minimal in spring at low latitudes (<25°N), peaks in the spring and is minimal in autumn at mid-latitudes (25°N to 50°N), while peaks in autumn and is minimal in spring at high latitudes (>50°N). This latitudinal shift of MBC seasonality is attributed to an interaction of soil temperature, soil moisture, and substrate availability. The MBC seasonality is inconsistent with patterns of heterotrophic respiration, indicating that MBC as a proxy for microbial activity is inappropriate at this resolution. This study highlights the need to explicitly represent microbial physiology in microbial models. The interactive controls of environments and substrate on microbial seasonality provide insights for better representing microbial mechanisms in simulating ecosystem functions at the seasonal scale.

Runoff change and sediment source during rainstorms in an ecologically constructed watershed on the Loess Plateau, China.

The sediment-reducing effect of check dams and the safety issues following dam breaks are long-standing concerns. This study analyzed the runoff change and sediment source during rainstorms in a small watershed using a multivariate mixed model and a comparative analysis of watersheds. The problem of sediment loss from dammed farmland following check dam break during rainstorms was evaluated. The results showed that the flood peak lag time (PLT) was significantly influenced by pre-soil moisture in cases of small amounts of rainfall but not during rainstorms. Ecological construction significantly reduced the linear correlation between rainfall and runoff modulus (RM). The reduction in sediment delivery modulus (SDM) due to the check dam was more significant than that in RM. The reduction in RM and SDM under rainstorm conditions were 16%-74% and 53%-93%, respectively. The contributions of inter-gully and gully lands to the sediment deposited in dammed farmland during a large rainstorm on July 26, 2017 were 38.07% and 61.93%, respectively. Soil erosion remained significant during large rainstorms. The increase in vegetation coverage on the hill slope increased the amount of sediment from gully lands. Check dam breaches have accounted for a loss of only 1.2% of the total area of the dammed farmland, and thus have not caused a large loss of sediment. However, breaches in them clearly increased the coefficient of variation of RM and SDM. Therefore, check dams have a critical effect on controlling sediment delivery at the watershed scale. Dam breaks do not result in a large percentage of sediment loss in the dammed farmland.