Particulate matter, polycyclic aromatic hydrocarbons and metals, platelet parameters and blood pressure alteration: Multi-pollutants study among population.

Epidemiological findings have determined the linkage of fine particulate matter (PM2.5) and the morbidity of hypertension. However, the mode of action and specific contribution of PM2.5 component in the blood pressure elevation remain unclear. Platelets are critical for vascular homeostasis and thrombosis, which may be involved in the increase of blood pressure. Among 240 high-PM2.5 exposed, 318 low-PM2.5 exposed workers in a coking plant and 210 workers in the oxygen plant and cold-rolling mill enrolled in present study, both internal and external exposure characteristics were obtained, and we performed linear regression, adaptive elastic net regression, quantile g-computation and mediation analyses to analyze the relationship between urine metabolites of polycyclic aromatic hydrocarbons (PAHs) and metals fractions with platelets indices and blood pressure indicators. We found that PM2.5 exposure leads to increased systolic blood pressure (SBP) and pulse pressure (PP). Specifically, for every 10 µg/m3 increase in PM2.5, there was a 0.09 mmHg rise in PP. Additionally, one IQR increase in urinary 1-hydroxypyrene (1.06 µmol/mol creatinine) was associated with a 3.43 % elevation in PP. Similarly, an IQR increment of urine cobalt (2.31 µmol/mol creatinine) was associated with a separate 1.77 % and 4.71 % elevation of SBP and PP. Notably, platelet-to-lymphocyte ratio (PLR) played a mediating role in the elevation of SBP and PP induced by cobalt. Our multi-pollutants results showed that PAHs and cobalt were deleterious contributors to the elevated blood pressure. These findings deepen our understanding of the cardiovascular effects associated with PM2.5 constituents, highlighting the importance of increased vigilance in monitoring and controlling the harmful components in PM2.5.

Achieving ultrahigh fatigue resistance in AlSi10Mg alloy by additive manufacturing.

Since the first discovery of the fatigue phenomenon in the late 1830s, efforts to fight against fatigue failure have continued. Here we report a fatigue resistance phenomenon in nano-TiB2-decorated AlSi10Mg enabled by additive manufacturing. This fatigue resistance mechanism benefits from the three-dimensional dual-phase cellular nanostructure, which acts as a strong volumetric nanocage to prevent localized damage accumulation, thus inhibiting fatigue crack initiation. The intrinsic fatigue strength limit of nano-TiB2-decorated AlSi10Mg was proven to be close to its tensile strength through the in situ fatigue tests of a defect-free microsample. To demonstrate the practical applicability of this mechanism, printed bulk nano-TiB2-decorated AlSi10Mg achieved fatigue resistance more than double those of other additive manufacturing Al alloys and surpassed those of high-strength wrought Al alloys. This strategy of additive-manufacturing-assisted nanostructure engineering can be extended to the development of other dual-phase fatigue-resistant metals.

Processing Laue Microdiffraction Raster Scanning Patterns with Machine Learning Algorithms: A Case Study with a Fatigued Polycrystalline Sample.

The massive amount of diffraction images collected in a raster scan of Laue microdiffraction calls for a fast treatment with little if any human intervention. The conventional method that has to index diffraction patterns one-by-one is laborious and can hardly give real-time feedback. In this work, a data mining protocol based on unsupervised machine learning algorithm was proposed to have a fast segmentation of the scanning grid from the diffraction patterns without indexation. The sole parameter that had to be set was the so-called "distance threshold" that determined the number of segments. A statistics-oriented criterion was proposed to set the "distance threshold". The protocol was applied to the scanning images of a fatigued polycrystalline sample and identified several regions that deserved further study with, for instance, differential aperture X-ray microscopy. The proposed data mining protocol is promising to help economize the limited beamtime.

A review on the effect of gut microbiota on metabolic diseases.

Human gut microbiota are a huge and complex microbial community, which is recognized to play a significant role in regulating host metabolism. However, the destruction of gut microbiota leads to the pathological response of host, and thus results in a variety of metabolic diseases. This article gives a brief review of research progress on gut microbiota and some main metabolic diseases, including osteoporosis, obesity, type 2 diabetes, non-alcoholic fatty liver, and hypertension, with a specific focus on the effect of gut microbiota on diseases' occurrence and development. In addition, this review article also shows some case studies on the regulation of gut microbiota by new means, such as fecal microbiota transplantation and oral probiotics. Although gut microbiota are considered as a promising novel target for the treatment of metabolic diseases, it is also necessary to encourage further studies to provide more valuable data for guiding the application of gut microbiota on disease therapy in future.

Residual-based pattern center calibration in high-resolution electron backscatter diffraction.

High resolution electron backscatter diffraction is an emerging technique of micro-structural characterization which can be used for local elastic strain measurement. Pattern center (PC) coordinate, an important parameter which affects accuracy of HR-EBSD, should be carefully calibrated before calculation. An integrated digital image correlation (IDIC) algorithm can extract the deformation gradient tensor and return the residual between reference and targeted images simultaneously. We propose to use the residual value as a criterion to calibrate PC, as an accurate PC value, accompanied with sample tilt parameters, results in slightly lower level of residuals when using simulated diffraction patterns. Though the reduction of residual value is small in the calibration process, our experimental dataset shows that the calibrated PC value will reduce the retrieved Von Mises strain, which results from the reduction of phantom strain caused by errors in the initially-guessed PC values given by the commercial software DynamicS.

Hot Deformation Behavior and Workability of In Situ TiB2/7050Al Composites Fabricated by Powder Metallurgy.

Isothermal compression tests of in situ TiB2/7050Al composites fabricated by powder metallurgy were performed at 300-460 °C with the strain rate varying from 0.001 s-1 to 1 s-1. The Arrhenius constitutive equation and hot processing map of composites were established, presenting excellent hot workability with low activation energies and broad processing windows. Dramatic discontinuous/continuous dynamic recrystallization (DDRX/CDRX) and grain boundary sliding (GBS) take place in composites during deformation, depending on the Zener-Hollomon parameter (Z) values. It was found that initially uniform TiB2 particles and fine grain structures are beneficial to the DDRX, which is the major softening mechanism in composites at high Z values. With the Z value decreasing, dynamic recovery and CDRX around particles are enhanced, preventing the occurrence of DDRX. In addition, fine grain structures in composites are stable at elevated temperature thanks to the pinning of dense nanoparticles, which triggers the occurrence of GBS and ensures good workability at low Z values.

Functional role of bloom-forming cyanobacterium Planktothrix in ecologically shaping aquatic environments.

Diverse metabolic behaviors endow microorganisms with various ecological functions, and metabolic activities of microbial species may affect the environmental conditions of their habitats. In this study, genome-guided analysis of Planktothrix spp. first divided these strains into six distinct groups, and comparisons of Planktothrix genomes revealed the inter- and intra-species variation. Prediction of central metabolism showed the functional diversity with regard to uptake of carbon, nitrogen, and sulfur sources. As the carbon-fixing microorganisms, Planktothrix isolates played a critical role in transforming the atmospheric carbon into organic carbon-the waterbodies' pool of available carbon. Diazotrophic lifestyle in certain Planktothrix strains may provide valuable avenues for supporting the equilibrium community. Furthermore, genome mining supported the exploration of biosynthetic gene clusters dedicated to cyanobacterial natural products, mainly including non-ribosomal peptide, polyketide, cyanobactin, and microviridin. Notably, some Planktothrix strains had the potential to non-ribosomally synthesize the microcystin (MC), a potent cyclic heptapeptide toxin, and MC-mediated cycling might strengthen the association between MC-producing and MC-degrading microorganisms. In short, genome-wide study of Planktothrix strains advances our current understanding of their metabolic potential and especially ecological roles in shaping natural environments.

Estimation of elastic strain by integrated image correlation on electron diffraction patterns.

High-angular-resolution electron backscattered diffraction (HR-EBSD) has been developed to study local elastic strains in crystals. An integrated digital image correlation (DIC) procedure for high resolution diffraction patterns, as recently proposed to bypass several problems of the conventional cross-correlation-based algorithm, was implemented. Through two examples of experimental data where the algorithm was used and compared to conventional means, the current paper illustrates the benefits of the integrated DIC method. It is found that both measurement uncertainty and computation time were simultaneously reduced. Moreover, an enhanced robustness was obtained for relatively high misorientations relative to methods based on cross-correlation. Different computing conditions are explored on experimental data. A number of practical usage conditions are proposed to achieve better precision and speed.

Amplified colorimetric sensor for detecting radon by its daughter lead based on the free-fixed auto-assembly structure of Duplex-hemin/G-quadruplex.

A novel signal amplification strategy based on a Pb2+-dependent DNAzyme is proposed for detecting Pb2+ and radon through Pb2+-induced DNAzyme cleavage and the auto-assembly of a duplex-hemin/G-quadruplex with two loop-stem structures and enzyme-mimicking catalytic activity. First, the Pb2+-specific DNAzyme cleaves a primer sequence, which induces assembly of the hairpin probe Hp1/Hp2 into a double helix structure. Subsequently, a G-quadruplex forms after the insertion of hemin into the free G-rich sequences; this G-quadruplex possesses the catalytic activity of horseradish peroxidase and changes colorless TMB to its deeply colored oxidized state. lead-dependent DNAzymes were constantly sheared by Pb2+, and the free primer strands were continuously assembled into double chains by hybridization with hairpin probes, providing amplification for the detection of lead (II) and radon. Under the optimum conditions, there was a good linear relationship between ΔA and the lead concentration for Pb2+ concentrations ranging from 2.58 to 18 nM, and the detection limit was 0.77 nM. Analysis of actual samples indicated that when the radon concentration was in the range of 5.41 × 103- 1.65 × 105 Bq·h/m3, the radon concentration and the absorbance were linearly correlated with a detection limit of 1.62 × 103 Bq·h/m3. During the process of radon sampling and detection, radiation damage from the radioactive gas radon can be avoided. In this study, the primer dissociated by the DNAzyme was in a free state. Compared with the fixed-state primer chain, this system will be more convenient for the biological analysis of ultratrace metal ions. Therefore, this strategy has good application prospects for biosensors and is expected to become a novel platform for the amplification and detection of metal ion signals.

Measuring topographies from conventional SEM acquisitions.

The present study extends the stereoscopic imaging principle for estimating the surface topography to two orientations, namely, normal to the electron beam axis and inclined at 70° as suited for EBSD analyses. In spite of the large angle difference, it is shown that the topography can be accurately determined using regularized global Digital Image Correlation. The surface topography is compared to another estimate issued from a 3D FIB-SEM procedure where the sample surface is first covered by a Pt layer, and its initial topography is progressively revealed from successive FIB-milling. These two methods are successfully compared on a 6% strained steel specimen in an in situ mechanical test. This analysis is supplemented by a third approach estimating the change of topography from crystal rotations as measured from successive EBSD images. This last technique ignores plastic deformation, and thus only holds in an elastic regime. For the studied example, despite the large plastic flow, it is shown that crystal rotation already accounts for a significant part of the deformation-induced topography.

On the use of SEM correlative tools for in situ mechanical tests.

In situ SEM mechanical tests are key to study crystal plasticity. In particular, imaging and diffraction (EBSD) allow microstructure and surface kinematics to be monitored all along the test. However, to get a full benefit from different modalities, it is necessary to register all images and crystallographic orientation maps from EBSD into the same frame. Different correlative approaches tracking either Pt surface markings, crystal orientations or grain boundaries, allow such registrations to be performed and displacement as well as rotation fields to be measured, a primary information for crystal plasticity identification. However, the different contrasts that are captured in different modalities and unavoidable stage motions also give rise to artifacts that are to be corrected to register the different information onto the same material points. The same image correlation tools reveal very powerful to correct such artifacts. Illustrated by an in situ uniaxial tensile test performed on a bainitic-ferritic steel sample, recent advances in image correlation techniques are reviewed and shown to provide a comprehensive picture of local strain and rotation maps.

Effects of a new nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) on nitrate and potassium leaching in two soils.

In this study, soil column was used to study the new nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) on nitrate (NO3(-)-N) and potassium (K) leaching in the sandy loam soil and clay loam soil. The results showed that DMPP with ammonium sulphate nitrate (ASN) ((NH4)2SO4 and NH4NO3) or urea could reduce NO3(-)-N leaching significantly, whereas ammonium (NH4(+)-N) leaching increased slightly. In case of total N (NO3(-)-N+NH4(+)-N), losses by leaching during the experimental period (40 d) were 37.93 mg (urea), 31.61 mg (urea+DMPP), 108.10 mg (ASN), 60.70 mg (ASN+DMPP) in the sandy loam soil, and 30.54 mg (urea), 21.05 mg (urea+DMPP), 37.86 mg (ASN), 31.09 mg (ASN+DMPP) in the clay loam soil, respectively. DMPP-amended soil led to the maintenance of relatively high levels of NH4(+)-N and low levels of NO3(-)-N in soil, and nitrification was slower. DMPP supplementation also resulted in less potassium leached, but the difference was not significant except the treatment of ASN and ASN+DMPP in the sandy loam soil. Above results indicate that DMPP is a good nitrification inhibitor, the efficiency of DMPP seems better in the sandy loam soil than in the clay loam soil and lasts longer.