The Polymorphisms in Methylenetetrahydrofolate Reductase, Methionine Synthase, Methionine Synthase Reductase, and the Risk of Colorectal Cancer

Polymorphisms in genes involved in folate metabolism may modulate the risk of colorectal cancer (CRC), but data from published studies are conflicting. The current meta-analysis was performed to address a more accurate estimation. A total of 41 (17,552 cases and 26,238 controls), 24(8,263 cases and 12,033 controls), 12(3,758 cases and 5,646 controls), and 13 (5,511 cases and 7,265 controls) studies were finally included for the association between methylenetetrahydrofolate reductase (MTHFR) C677T and A1289C, methione synthase reductase (MTRR) A66G, methionine synthase (MTR) A2756G polymorphisms and the risk of CRC, respectively. The data showed that the MTHFR 677T allele was significantly associated with reduced risk of CRC (OR = 0.93, 95%CI 0.90-0.96), while the MTRR 66G allele was significantly associated with increased risk of CRC (OR = 1.11, 95%CI 1.01-1.18). Sub-group analysis by ethnicity revealed that MTHFR C677T polymorphism was significantly associated with reduced risk of CRC in Asians (OR = 0.80, 95%CI 0.72-0.89) and Caucasians (OR = 0.84, 95%CI 0.76-0.93) in recessive genetic model, while the MTRR 66GG genotype was found to significantly increase the risk of CRC in Caucasians (GG vs. AA: OR = 1.18, 95%CI 1.03-1.36). No significant association was found between MTHFR A1298C and MTR A2756G polymorphisms and the risk of CRC. Cumulative meta-analysis showed no particular time trend existed in the summary estimate. Probability of publication bias was low across all comparisons illustrated by the funnel plots and Egger's test. Collectively, this meta-analysis suggested that MTHFR 677T allele might provide protection against CRC in worldwide populations, while MTRR 66G allele might increase the risk of CRC in Caucasians. Since potential confounders could not be ruled out completely, further studies were needed to confirm these results

Abeta42-Induced Neurodegeneration via an Age-Dependent Autophagic-Lysosomal Injury in Drosophila

The mechanism of widespread neuronal death occurring in Alzheimer's disease (AD) remains enigmatic even after extensive investigation during the last two decades. Amyloid beta 42 peptide (Aβ1–42) is believed to play a causative role in the development of AD. Here we expressed human Aβ1–42 and amyloid beta 40 (Aβ1–40) in Drosophila neurons. Aβ1–42 but not Aβ1–40 causes an extensive accumulation of autophagic vesicles that become increasingly dysfunctional with age. Aβ1–42-induced impairment of the degradative function, as well as the structural integrity, of post-lysosomal autophagic vesicles triggers a neurodegenerative cascade that can be enhanced by autophagy activation or partially rescued by autophagy inhibition. Compromise and leakage from post-lysosomal vesicles result in cytosolic acidification, additional damage to membranes and organelles, and erosive destruction of cytoplasm leading to eventual neuron death. Neuronal autophagy initially appears to play a pro-survival role that changes in an age-dependent way to a pro-death role in the context of Aβ1–42 expression. Our in vivo observations provide a mechanistic understanding for the differential neurotoxicity of Aβ1–42 and Aβ1–40, and reveal an Aβ1–42-induced death execution pathway mediated by an age-dependent autophagic-lysosomal injury

Innovative Coating–Etching Method of Biocarrier Fabrication for Treating Wastewater with a Low C/N Ratio

A novel method was used to fabricate the bio-carrier with both a high specific surface area and good compatibility. The results of monitoring the growth of biofilms at a low C/N ratio (0.83) showed that resulting carrier-PLA-cavity offered certain advantages for biofilm growth by providing an appropriate microenvironment for bacterial growth in wastewater treatment. The biofilm on carrier-PLA-cavity grew and updated faster than the naked-carrier. The biomass and thickness of biofilms growing on carrier-PLA-cavity were 10 kg/m3 and 500 μm, respectively. From the wastewater tests, 90% of the total nitrogen was removed via simultaneous nitrification and denitrification (SND) by the biofilm biomass attached to carrier-PLA-cavity, compared to 68% for the naked-carrier. The COD removal efficiency values of the carrier-PLA-cavity and naked-carrier were 94% and 86%, respectively. The microbial community analysis of carrier biofilms showed that Halomonas was the most abundant genus, and heterotrophic nitrification and denitrification were responsible for nitrogen removal in both reactors. Notably, this method does not require any complicated equipment or structural design. This novel method might be a promising strategy for fabricating biocarriers for treating wastewater with a low C/N ratio

Temporal Information Extraction for Afforestation in the Middle Section of the Yarlung Zangbo River Using Time-Series Landsat Images Based on Google Earth Engine

Afforestation is one of the most efficient ways to control land desertification in the middle section of the Yarlung Zangbo River (YZR) valley. However, the lack of a quantitative way to record the planting time of artificial forest (AF) constrains further management for these forests. The long-term archived Landsat images (including the Thematic Mapper (TM), Enhanced Thematic Mapper Plus (ETM+), and Operational Land Imager (OLI)) provide a good opportunity to capture the temporal change information about AF plantations. Under the condition that there would be an abrupt increasing trend in the normalized difference vegetation index (NDVI) time-series curve after afforestation, and this characteristic can be thought of as the indicator of the AF planting time. To extract the indicator, an algorithm based on the Google Earth Engine (GEE) for detecting this trend change point (TCP) on the maximum NDVI time series within the growing season (May to September) was proposed. In this algorithm, the time-series NDVI was initially smoothed and segmented into two subspaces. Then, a trend change indicator Sdiff was calculated with the difference between the fitting slopes of the subspaces before and after each target point. A self-adaptive method was applied to the NDVI series to find the right year with the maximum TCP, which is recorded as the AF planting time. Based on the proposed method, the AF planting time of the middle section of the YZR valley from 1988 to 2020 was derived. The detected afforestation temporal information was validated by 222 samples collected from the field survey, with a Pearson correlation coefficient of 0.93 and a root mean squared error (RMSE) of 2.95 years. Meanwhile, the area distribution of the AF planted each year has good temporal consistency with the implementation of the eco-reconstruction project. Overall, the study provides a good way to map AF planting times that is not only helpful for sustainable management of AF areas but also provides a basis for further research on the impact of afforestation on desertification control

Improvement of Corrosion Resistance and Electrical Conductivity of Stainless Steel 316L Bipolar Plate by Pickling and Passivation

Corrosion resistance and electrical conductivity of stainless steel bipolar plate remains a big challenge while it has been regarded as the most promising candidate for proton exchange membrane fuel cell. The purpose of this paper is to study the effects of pickling and passivation by sulfuric acid and a mixture of nitric and fluoric acids, respectively, on corrosion resistance and electrical conductivity of stainless steel 316L (SS316L) bipolar plate. First, pickling of the specimens of SS316L is performed in a 15 wt.% H2SO4. Afterwards, the specimens are passivated in a mixture of 12 wt.% HF and 4 wt.% HNO3. Electrochemical and interfacial conductivity tests are conducted to examine the change in corrosion resistance and electrical conductivity of SS316L. Finally, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) reveal the evolution of surface morphology, chemical composition and surface conductivity. The results show that the corrosion resistance and electrical conductivity of SS316L could be improved significantly by pickling and passivation. The increase in Cr:Fe ratio as well as a more uniform surface with higher conductivity is the main reason for the improvement of corrosion resistance and interfacial conductivity of SS316L

Temporal Information Extraction for Afforestation in the Middle Section of the Yarlung Zangbo River Using Time-Series Landsat Images Based on Google Earth Engine

Afforestation is one of the most efficient ways to control land desertification in the middle section of the Yarlung Zangbo River (YZR) valley. However, the lack of a quantitative way to record the planting time of artificial forest (AF) constrains further management for these forests. The long-term archived Landsat images (including the Thematic Mapper (TM), Enhanced Thematic Mapper Plus (ETM+), and Operational Land Imager (OLI)) provide a good opportunity to capture the temporal change information about AF plantations. Under the condition that there would be an abrupt increasing trend in the normalized difference vegetation index (NDVI) time-series curve after afforestation, and this characteristic can be thought of as the indicator of the AF planting time. To extract the indicator, an algorithm based on the Google Earth Engine (GEE) for detecting this trend change point (TCP) on the maximum NDVI time series within the growing season (May to September) was proposed. In this algorithm, the time-series NDVI was initially smoothed and segmented into two subspaces. Then, a trend change indicator Sdiff was calculated with the difference between the fitting slopes of the subspaces before and after each target point. A self-adaptive method was applied to the NDVI series to find the right year with the maximum TCP, which is recorded as the AF planting time. Based on the proposed method, the AF planting time of the middle section of the YZR valley from 1988 to 2020 was derived. The detected afforestation temporal information was validated by 222 samples collected from the field survey, with a Pearson correlation coefficient of 0.93 and a root mean squared error (RMSE) of 2.95 years. Meanwhile, the area distribution of the AF planted each year has good temporal consistency with the implementation of the eco-reconstruction project. Overall, the study provides a good way to map AF planting times that is not only helpful for sustainable management of AF areas but also provides a basis for further research on the impact of afforestation on desertification control

Research progress in carbon fiber sizing agents for PEEK composites

Thermoplastic polyether ether ketone (PEEK) composites are widely used in aerospace field due to their excellent fracture toughness, impact resistance and material versatility. Sizing agent as the core auxiliary product of carbon fiber has an important impact on the interface of composites. Limited by the decomposition temperature, the traditional thermosetting sizing agents are difficult to meet the use of PEEK composites, which restricts the development and application of high-performance PEEK composites. Therefore, it is of great significance to develop a matching carbon fiber sizing agent for PEEK composites. In this paper, the interfacial properties of composites and the action mechanism of sizing agent were analyzed and introduced; the research progress and results of modified PEEK, polyimide precursor and polyetherimide sizing agents were focused, and different systems of sizing agents were analyzed and summarized.Finally, the relevant suggestions on carbon fiber sizing agents for PEEK composites were put forward while the environmental and multi-function developments for sizing agents were prospected

Curing process and thermal stability of polyimide-matrix composite for aero-engines

Aiming at the need of aero-engines, investigation was made into the curing process and thermal stability of a polyimide-matrix structural composite. The curing kinetic equation of EC-380A resin was established. The curing degree of the resin was simulated as a function of the curing temperature and time. Further, combined with the resin rheology, the curing process of the EC-380A composite was established and verified. Large-scaled aero-engine typical structural components were fabricated. Thermal stability of the composite was estimated by mass loss, internal quality of the flaw-embedded laminate, and mechanical property after thermal ageing. By multi-temperature step curing at 330-380℃, the flaw-free composite could be manufactured under the circumstance of an integrated layup. The composite has excellent thermal stability with thermal resistance of 370-400℃. The mass loss rate is around 1.3% after ageing for 1000 h at 370℃ and 285℃.No new flaw or propagation of the embedded flaw occurs for the composite after thermal ageing at 400℃, indicating a high-temperature structural stability

In vitro propagation, shoot regeneration, callus induction, and suspension from lamina explants of Sorbus caloneura

Sorbus caloneura has high ornamental and medicinal value but is endangered, and significant effort is required to preserve this natural resource. In this study, the stem and sterilized leaves of S. caloneura were used to explore the effects of different plant hormones basic medium type, initial callus quality, initial liquid volume, and ratio of old liquid culture medium to new on stem proliferation, regeneration and callus suspension culture. Naphthylacetic acid (NAA) and 6-benzyladenine (6-BA) significantly affected the proliferation of stem tissue. Murashige and Skoog (MS) basal medium supplemented with 1.75 mg/L 6-BA, 0.25 mg/L NAA, and 0.25 mg/L indole butyric acid (IBA) yielded a proliferation rate of 100%, with an average number of adventitious shoots per stem of 4.9. The best callus induction was observed with MS basal medium containing 0.5 mg/L 6-BA, 1 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D), and 0.2 mg/L thidiazuron (TDZ). The adventitious shoots were directly induced by MS basal medium containing 5.0 mg/L 6-BA, 0.5 mg/L NAA, and 1.5 mg/L kinetin (KT) and indirectly induced by medium containing 3.0 mg/L 6-BA, 0.3 mg/L NAA, and 0.1 mg/L TDZ. NAA significantly affected rooting rate, with ideal conditions found to be medium supplemented with 0.2 mg/L NAA and 1.5 mg/L IBA. MS basal medium with 4.5 g of calli and 120 mL of liquid culture medium without retention of the original culture medium yielded the best suspension effect for callus proliferation. Taken together, the results of this study lay a foundation for the breeding, preservation of germplasm resources, and genetic transformation of S. caloneura