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•V-6Cr-6Ti pre-alloy powder applied in SLM processing was successfully prepared.•Strong texture within molten pool formed by applying double-region orthometric scanning strategy.•The ...compression strength of SLM-processed V-6Cr-6Ti was superior.•Molten pool boundary sliding played an important role in shear deformation during compression test.
Selective laser melting (SLM) additive manufacturing technology has been a prevailing method to fabricate components with complex physical geometry or novel structural design. However, original nuclear powder material such as vanadium-based alloy appropriate for SLM processing has yet not been obtained commercially, which significantly restricts the development of nuclear component manufacturing. In this study, near-sphere, uniform and fine V-6Cr-6Ti pre-alloy powder which met the performance demands for SLM processing was successfully obtained by high-energy ball milling. Subsequently, the V-6Cr-6Ti part was fabricated by SLM consolidation of as-prepared pre-alloy powder with double-region orthometric scanning strategy, forming strong texture feature within molten pool. The compression test was performed, showing that the maximum compression stress reached 1078MPa and the accumulated strain was about 0.32.
Reduction in snow cover is a prominent aspect of global change. Freeze–thaw cycles (FTCs) of different amplitudes and durations in soil due to insufficient thermal insulation may alter microbial ...diversity and key ecological functions mediated by microorganisms. These changes could then further alter the cycling of material and energy in the ecosystem. Yet despite many assessments, the impact of FTCs upon microbial diversity remains poorly understood. Here, 546 observations from 61 published studies were collected for a global meta-analysis with the objective to explore how soil microbial diversity and C and N dynamics it drives respond to FTCs. The results showed that: in general, FTCs did not lead to a reduction of microbial α-diversity, but they did reduce levels of soil microbial biomass carbon, microbial biomass nitrogen, and phospholipid fatty acid by 7%, 12%, and 11%, respectively; they also significantly changed the microbial community structure. FTCs did not significantly affect the α-diversity of bacteria and fungi, but community structures of both were changed significantly, with that of the bacteria more sensitive to FTCs. FTCs were responsible for a 6% decrease in functions related to C, N cycling, which could be explained by the changes found in microbial biomass and community structure. FTCs could also indirectly impact microbial biomass via changed pH and soil water content (SWC). The response of microbial community to FTCs was related to the FTC frequency, freezing temperature and sampling time. FTCs had a large effect on the C and N pool components and fluxes in soil. It is particularly noteworthy that FTCs drove a 137% increase in N2O emission. Further, the changes in pH and SWC directly affected the C and N pool components and fluxes. The results of current meta-analysis deepen the comprehensive understanding of the effects of FTCs on the soil microbial community and C and N dynamics it mediated, and provide a reference for subsequent research in terms of experimental scheme and scientific issues requiring close attention.
•Freeze–thaw cycles (FTCs) altered microbial biomass and structure, but not diversity.•Community structure of bacteria was more sensitive to FTCs than that of fungi.•Microbial responses were related to FTC patterns.•Microbial biomass and structure explained functions related to C, N cycling.
•The relative density of TiC/316L composites part fabricated by SLM reaches 98.34%.•Nano-TiC particles enhance the microhardness of the matrix from Hv0.3 = 219.1 to 277.6.•The tensile strength is ...improved from 627.5 MPa to 748.6 MPa with the addition of TiC.•Effects of processing parameters and TiC on density and strength are discussed.
Metal matrix composite parts produced using selective laser melting have superior mechanical properties to those produced using traditional powder metallurgy. In this study, nanocrystalline TiC reinforced 316L stainless steel composite parts were fabricated using selective laser melting, and the effects of the TiC mass fraction, particle size, and processing parameters on the relative density, microhardness, and mechanical properties of the TiC/316L composites were investigated. The results show that the relative density of the fabricated parts is related to the laser power and exposure time, and increases when these parameters are increased. The greater the mass fraction of nano-TiC added, the more severe the degree of spheroidization and the lower the density of the resulting material. The microhardness of the 316L stainless steel parts is enhanced by the nano-TiC particles, and increases with increasing nano-TiC mass fraction. The tensile strength is improved with longer exposure time and with the addition of 2 wt% nano-TiC particles. Compared with pure 316L, the microhardness of the TiC/316L composite parts fabricated with 2 wt% 40 nm TiC enhanced from HV0.3 = 219.1 to 277.6, and the ultimate tensile strength significantly increased from 627.5 to 748.6 MPa. The strengthening mechanism of TiC particles is the refinement of the grain size of the 316L matrix, and the greater amount of TiC particles added, the better the grain refinement of 316L.
Abstract
Human gut microbiome is a promising target for managing type 2 diabetes (T2D). Measures altering gut microbiota like oral intake of probiotics or berberine (BBR), a bacteriostatic agent, ...merit metabolic homoeostasis. We hence conducted a randomized, double-blind, placebo-controlled trial with newly diagnosed T2D patients from 20 centres in China. Four-hundred-nine eligible participants were enroled, randomly assigned (1:1:1:1) and completed a 12-week treatment of either BBR-alone, probiotics+BBR, probiotics-alone, or placebo, after a one-week run-in of gentamycin pretreatment. The changes in glycated haemoglobin, as the primary outcome, in the probiotics+BBR (least-squares mean 95% CI, −1.04−1.19, −0.89%) and BBR-alone group (−0.99−1.16, −0.83%) were significantly greater than that in the placebo and probiotics-alone groups (−0.59−0.75, −0.44%, −0.53−0.68, −0.37%, P < 0.001). BBR treatment induced more gastrointestinal side effects. Further metagenomics and metabolomic studies found that the hypoglycaemic effect of BBR is mediated by the inhibition of DCA biotransformation by
Ruminococcus bromii
. Therefore, our study reports a human microbial related mechanism underlying the antidiabetic effect of BBR on T2D. (Clinicaltrial.gov Identifier: NCT02861261).
Antidiabetic medication may modulate the gut microbiota and thereby alter plasma and faecal bile acid (BA) composition, which may improve metabolic health. Here we show that treatment with Acarbose, ...but not Glipizide, increases the ratio between primary BAs and secondary BAs and plasma levels of unconjugated BAs in treatment-naive type 2 diabetes (T2D) patients, which may beneficially affect metabolism. Acarbose increases the relative abundances of Lactobacillus and Bifidobacterium in the gut microbiota and depletes Bacteroides, thereby changing the relative abundance of microbial genes involved in BA metabolism. Treatment outcomes of Acarbose are dependent on gut microbiota compositions prior to treatment. Compared to patients with a gut microbiota dominated by Prevotella, those with a high abundance of Bacteroides exhibit more changes in plasma BAs and greater improvement in metabolic parameters after Acarbose treatment. Our work highlights the potential for stratification of T2D patients based on their gut microbiota prior to treatment.
Since probability hypothesis density (PHD) filters do not need explicit data association, they have recently been widely used in radar multi-target tracking (MTT). However, in existing PHD filters, ...sampling times are generally considered the same for all targets. Due to the limitation of antenna beam width in radar applications, the same sampling time for all targets will lead to a mismatch between the predicted data and measurement data, reducing the accuracy of radar MTT. In order to eliminate the estimation error with less computational cost, a radar nonlinear multi-target tracking method with a parallel PHD filter is proposed in this article. The measurement area is divided into several subspaces according to the beam width of the radar antenna, and the PHD of all subspaces is calculated in parallel. Then, multi-feature information in radar echo assists tracking and improves real-time performance. Experimental results in various scenarios illustrate that the proposed method can eliminate the estimation errors introduced by sampling time diversity at the cost of less computation cost, especially in cluttered environments.
The decarbonization of the shipping industry has risen to a new level of significance on the agendas of policy makers and strategic decision makers. This paper focuses on the likely cost implications ...for the shipping industry of recently implemented, and future planned policies that seek to reduce the carbon footprint of the sector. The scale of the problem is presented through a summary review of the International Maritime Organization’s fourth greenhouse gas study of 2020. The regulatory context, which is emerging as a response to overcoming this challenge, is analyzed at both the global and EU level. The potential cost implications for the future, in terms of this new regulatory context, are then analyzed on the basis of a review of academic and industry sources. Our paper concludes that alternative, zero-carbon fuels are the best way forward, but that operational and technological innovations will not be sufficient to bring about the complete decarbonization of the industry within the foreseeable future. Thus, market-based measures are required. Finally, the options available, and the likely implications of each of these options, is addressed, suggesting that there will be both winners and losers in the race to decarbonize the shipping industry.
•The microstructure was featured with 〈001〉B2//BD and uniformly dispersed Ti4Ni2Ox nanoparticles;•The cleavage fracture along the texture orientation predominated during the impact loading;•The ...cleavage crack could originate from dislocation pile-ups and micro voids.
A Ni-rich NiTi alloy sample was fabricated by laser powder bed fusion and its solidified microstructure included a strong texture orientation of 〈001〉B2//BD and uniformly dispersed Ti4Ni2Ox nanoparticles. The drop weight tearing test was then performed to reveal its impact fracture behavior. The force–displacement curve presented a typical three-stage feature and the steady crack propagation rate reached ∼53.087 m/s. The fracture surface was predominated by the cleavage river pattern with a cleavage direction roughly parallel to the texture orientation. The initiation and propagation of cleavage crack could originate from dislocation pile-ups on {011}B2 plane and micro voids formed at the matrix/nanoparticle interface.
Paraffin odor intensity is an important quality indicator when a paraffin inspection is performed. Currently, paraffin odor level assessment is mainly dependent on an artificial sensory evaluation. ...In this paper, we developed a paraffin odor analysis system to classify and grade four kinds of paraffin samples. The original feature set was optimized using Principal Component Analysis (PCA) and Partial Least Squares (PLS). Support Vector Machine (SVM), Random Forest (RF), and Extreme Learning Machine (ELM) were applied to three different feature data sets for classification and level assessment of paraffin. For classification, the model based on SVM, with an accuracy rate of 100%, was superior to that based on RF, with an accuracy rate of 98.33-100%, and ELM, with an accuracy rate of 98.01-100%. For level assessment, the R² related to the training set was above 0.97 and the R² related to the test set was above 0.87. Through comprehensive comparison, the generalization of the model based on ELM was superior to those based on SVM and RF. The scoring errors for the three models were 0.0016-0.3494, lower than the error of 0.5-1.0 measured by industry standard experts, meaning these methods have a higher prediction accuracy for scoring paraffin level.
Context: Berberine, a natural plant alkaloid, is usually used as an antibiotic drug. The potential glucose-lowering effect of berberine was noted when it was used for diarrhea in diabetic patients. ...In vitro and in vivo studies have then showed its effects on hyperglycemia and dyslipidemia.
Objective: The objective of the study was to evaluate the efficacy and safety of berberine in the treatment of type 2 diabetic patients with dyslipidemia.
Design: One hundred sixteen patients with type 2 diabetes and dyslipidemia were randomly allocated to receive berberine (1.0 g daily) and the placebo for 3 months. The primary outcomes were changes in plasma glucose and serum lipid concentrations. Glucose disposal rate (GDR) was measured using a hyperinsulinemic euglycemic clamp to assess insulin sensitivity.
Results: In the berberine group, fasting and postload plasma glucose decreased from 7.0 ± 0.8 to 5.6 ± 0.9 and from 12.0 ± 2.7 to 8.9 ± 2.8 mm/liter, HbA1c from 7.5 ± 1.0% to 6.6 ± 0.7%, triglyceride from 2.51 ± 2.04 to 1.61 ± 1.10 mm/liter, total cholesterol from 5.31 ± 0.98 to 4.35 ± 0.96 mm/liter, and low-density lipoprotein-cholesterol from 3.23 ± 0.81 to 2.55 ± 0.77 mm/liter, with all parameters differing from placebo significantly (P < 0.0001, P < 0.0001, P < 0.0001, P = 0.001, P < 0.0001, and P <0.0001, respectively). The glucose disposal rate was increased after berberine treatment (P = 0.037), although no significant change was found between berberine and placebo groups (P = 0.063). Mild to moderate constipation was observed in five participants in the berberine group.
Conclusions: Berberine is effective and safe in the treatment of type 2 diabetes and dyslipidemia.
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