Investigation on the control of inclusions and tensile strength in Ce-treated P110-grade oil casing steel.

This research added rare Earth elements Ce to the P110-grade oil casing steel to reveal their influence on the inclusions and tensile properties. The content of cerium in the steel varied from 0 to 452 ppm. Based on the classical thermodynamic calculation, the predominance diagram of Re-containing inclusions in P110-grade steel was obtained. The evolution route of the inclusions composition with the increasing cerium content in the steel was xCaO⋅yAl2O3 → Al2O3-CeAlO3 → Ce2O3-CeAlO3 → Ce2O3-Ce2O2S → Ce2O2S, which agreed well with the thermodynamic analysis. As the cerium content at 235 ppm, the size of Ce containing inclusions has a minimal size at 2.82 µm. Suitable Ce content can modify the big-size xCaO⋅yAl2O3 inclusions into small-size Re-containing inclusions. The results demonstrate that the tensile performance of this steel can be improved as the cerium content increases from 0 to 235 ppm. However, once the cerium content exceeds 235 ppm, further increases in cerium content led to a decline in performance. The experimental results shows that the presence of large-sized Ce2O2S inclusions and the change of microstructure, will lead to the decrease in tensile performance.

Regional Thermal Radiation Characteristics of FY Satellite Remote Sensing Based on Big Data Analysis.

It is of great significance to study the thermal radiation anomalies of earthquake swarms in the same area in terms of selecting abnormal characteristic determination parameters, optimizing and determining the processing model, and understanding the abnormal machine. In this paper, we investigated short-term and long-term thermal radiation anomalies induced by earthquake swarms in Iran and Pakistan between 2007 and 2016. The anomalies were extracted from infrared remote sensing black body temperature data from the China Geostationary Meteorological Satellites (FY-2C/2E/2F/2G) using the multiscale time-frequency relative power spectrum (MS T-FRPS) method. By analyzing and summarizing the thermal radiation anomalies of series earthquake groups with consistency law through a stable and reliable MS T-FRPS method, we first obtained the relationship between anomalies and ShakeMaps from USGS and proposed the anomaly regional indicator (ARI) to determine seismic anomalies and the magnitude decision factor (MDF) to determine seismic magnitude. In addition, we explored the following discussions: earthquake impact on regional thermal radiation background and the relationship between thermal anomalies and earthquake magnitude and the like. Future research directions using the MS T-FRPS method to characterize regional thermal radiation anomalies induced by strong earthquakes could help improve the accuracy of earthquake magnitude determination.

Study on the spatial characteristics of the digital economy on urban carbon emissions.

This paper explores the spatial impact effects and spatio-temporal heterogeneity of the digital economy on urban carbon emissions (CO2). Specifically, firstly, the Digital Economy Index (DEI) system of 285 cities in China was constructed and the Global Principal Component Analysis (GPCA) was applied to evaluate the digital economy level of Chinese cities. Based on spatial correlation and spatial heterogeneity, the paper explores the global spatial impact and spatio-temporal heterogeneity of the impact of digital economy on CO2 using spatial Durbin model (SDM) and geographic time-weighted regression (GTWR), respectively. And the mechanism variables are used to further demonstrate the mechanism effect and nonlinear characteristics of the impact of digital economy on CO2. The findings indicate that (1) the advancement of the digital economy is beneficial for achieving carbon abatement goals, and the impact of the digital economy on CO2 mitigation remains stable across several robustness tests. (2) The spatial spillover effect of the digital economy on the impact of carbon reduction is not significant. And there is significant temporal and spatial heterogeneity in the impact of the digital economy on carbon emissions. (3) According to the mechanism analysis, the digital economy reduces carbon emissions by encouraging the development of green technologies and promoting the modernization of industrial structures. And there are non-linear characteristics of this effect. This study concludes that the digital economy can support China's goal of achieving "carbon peak and carbon neutrality." However, it is important to consider the differences in urban development over time and space. Leveraging the city's strengths to develop a digital economy in a unique way that will help achieve China's carbon reduction goals.

New Insights into the Mechanism of Nucleation of ZrO2 Inclusions at High Temperature.

It is difficult to observe the nucleation mechanism of inclusions in real-time. In this study, the nucleation process of zirconium oxide inclusions was systematically studied by classical nucleation theory and first principles. Zr deoxidized steel with 100 ppm Zr addition was processed into metallographic samples for scanning electron microscopy energy-dispersive spectroscopy observation. The electrolytic sample was analyzed by micro X-ray diffraction and transmission electron microscopy, and the zirconium oxide in the sample was determined to be ZrO2. The nucleation rate and radius of the ZrO2 inclusions were calculated by classical nucleation theory, and they were compared with the experimental values. There was a considerable difference between the experimental and theoretical values of the nucleation rate. The effect of the nucleation size was analyzed by first-principles calculation, and the thermodynamic properties of ZrO2 clusters and nanoparticles were analyzed by constructing (ZrO2)n (n = 1-6) clusters. The thermodynamic properties of ZrO2 calculated by first principles were consistent with the values in the literature. Based on two-step nucleation theory, the nucleation pathway of ZrO2 is as follows: Zratom + Oatom → (ZrO2)n → (ZrO2)2 → core (ZrO2 particle)-shell ((ZrO2)2 cluster) nanoparticle → (ZrO2)bulk.

A genetic map of the chromatin regulators to drug response in cancer cells.

BACKGROUND: Diverse drug vulnerabilities owing to the Chromatin regulators (CRs) genetic interaction across various cancers, but the identification of CRs genetic interaction remains challenging. METHODS: In order to provide a global view of the CRs genetic interaction in cancer cells, we developed a method to identify potential drug response-related CRs genetic interactions for specific cancer types by integrating the screen of CRISPR-Cas9 and pharmacogenomic response datasets. RESULTS: Totally, 625 drug response-related CRs synthetic lethality (CSL) interactions and 288 CRs synthetic viability (CSV) interactions were detected. Systematically network analysis presented CRs genetic interactions have biological function relationship. Furthermore, we validated CRs genetic interactions induce multiple omics deregulation in The Cancer Genome Atlas. We revealed the colon adenocarcinoma patients (COAD) with mutations of a CRs set (EP300, MSH6, NSD2 and TRRAP) mediate a better survival with low expression of MAP2 and could benefit from taxnes. While the COAD patients carrying at least one of the CSV interactions in Vorinostat CSV module confer a poor prognosis and may be resistant to Vorinostat treatment. CONCLUSIONS: The CRs genetic interaction map provides a rich resource to investigate cancer-associated CRs genetic interaction and proposes a powerful strategy of biomarker discovery to guide the rational use of agents in cancer therapy.

Systematic exploration of the underlying mechanism of gemcitabine resistance in pancreatic adenocarcinoma.

Resistance to gemcitabine is the main challenge of chemotherapy for pancreatic ductal adenocarcinoma (PDAC). Hence, the development of a response signature to gemcitabine is essential for precision therapy of PDAC. However, existing quantitative signatures of gemcitabine are susceptible to batch effects and variations in sequencing platforms. Therefore, based on within-sample relative expression ordering of pairwise genes, we developed a transcriptome-based gemcitabine signature consisting of 28 gene pairs (28-GPS) that could predict response to gemcitabine for PDAC at the individual level. The 28-GPS was superior to previous quantitative signatures in terms of classification accuracy and prognostic performance. Resistant samples classified by 28-GPS showed poorer overall survival, higher genomic instability, lower immune infiltration, higher metabolic level and higher-fidelity DNA damage repair compared with sensitive samples. In addition, we found that gemcitabine combined with phosphoinositide 3-kinase (PI3K) inhibitor may be an alternative treatment strategy for PDAC. Single-cell analysis revealed that cancer cells in the same PDAC sample showed both the characteristics of sensitivity and resistance to gemcitabine, and the activation of the TGFß signalling pathway could promote progression of PDAC. In brief, 28-GPS could robustly determine whether PDAC is resistant or sensitive to gemcitabine, and may be an auxiliary tool for clinical treatment.

A transcriptional signature detects homologous recombination deficiency in pancreatic cancer at the individual level.

Pancreatic cancer (PC) with homologous recombination deficiency (HRD) has been reported to benefit from poly ADP-ribose polymerase (PARP) inhibitors. However, accurate identification of HRD status for PC patients from the transcriptional level is still a great challenge. Here, based on a relative expression ordering (REO)-based algorithm, we developed an HRD signature including 24 gene pairs (24-GPS) using PC transcriptional profiles from The Cancer Genome Atlas (TCGA). HRD samples classified by 24-GPS showed worse overall survival (p = 4.4E-3 for TCGA; p = 1.2E-3 for International Cancer Genome Consortium-Australia cohort; p = 6.4E-2 for GSE17891; p = 7.5E-2 for GSE57495) and higher HRD scores than non-HRD samples (p = 1.4E-4). HRD samples showed highly unstable genomic characteristics and also displayed HRD-related alterations at the epigenomic and proteomic levels. Moreover, HRD cell lines identified by 24-GPS tended to be sensitive to PARP inhibitors (p = 6.6E-2 for olaparib; p = 2.6E-3 for niraparib). Compared with the non-HRD group, the HRD group presented lower immune scores and CD4/CD8 T cell infiltration proportion. Interestingly, PC tumor cells with co-inhibition of PARP-related genes and ATR showed reduced survival ability. In conclusion, 24-GPS can robustly identify PC patients with HRD status at the individualized level.

A Kinetic Model for the Modification of Al2O3 Inclusions during Calcium Treatment in High-Carbon Hard Wire Steel.

Laboratory-scale experiments for the modification of Al2O3 inclusions by calcium treatment in high-carbon hard wire steel were performed and the compositions and morphological evolution of inclusions were studied. The kinetics of the modification of Al2O3 inclusions by calcium treatment were studied in high-carbon hard wire steel based on the unreacted shrinking core model, considering the transfer of Ca and Al through the boundary layer and within the product layer, coupled with thermodynamic equilibrium at the interfaces. The diffusion of Al in the inclusion layer was the limiting link in the inclusion modification process. The Ca concentration in molten steel had the greatest influence on the inclusion modification time. The modification time for inclusions tended to be longer in the transformation of higher CaO-containing calcium aluminate. The modification of Al2O3 into CA6 was fastest, while the most time was needed to modify CA into C12A7. It took about six times time longer at the later stage of inclusion modification than at the early stage. The complete modification time for inclusions increased with the square of their radii. The changes of CaO contents with melting time were estimated based on a kinetic model and was consistent with experimental results.

Effect of Mg Treatment on the Nucleation and Ostwald Growth of Inclusions in Fe-O-Al-Mg Melt.

This study aimed to investigate the effect of Mg treatment on the nucleation and ostwald growth of inclusions. Deoxidized experiments with Al (0.05%Al) and Al-Mg (0.05%Al + 0.03%Mg) were carried out at 1873 K, and the composition, number, and size of inclusions were studied as a function of holding time. Homogeneous nucleation theory and ostwald ripening were utilized to calculate the nucleation rate, the critical size of nuclei, and coarsening rate of inclusions. The results show that small inclusions were more easily found in the steels with Al-Mg complex deoxidation, and the number of inclusions with Al-Mg complex deoxidation is larger at an early stage of deoxidation. The critical size of nuclei increases in the order of MgAl2O4 (0.3-0.4 nm) < Al2O3 (0.4-0.6 nm), and the nucleation rate increases in the order of Al2O3 (1100 cm-3 s-1) < MgAl2O4 (1200 cm-3s-1), which is consistent with the experimental results. Moreover, the coarsening rate of MgAl2O4 inclusions was smaller than Al2O3 inclusions in both the value of kd(cal.) from ostwald growth and the value of kd(obs.) from inclusion size. The effect of Mg addition on coarsening of inclusion was analyzed and their mechanism was discussed based on ostwald ripening theory and Factsage calculation.

Inclusion Characteristics in 95CrMo Steels with Different Calcium and Sulfur Contents.

In order to study the effect of Ca and sulfur contents on the characteristics of inclusions, industrial experiments using 95CrMo steel were conducted. SEM-EDS detections and stereological analysis were used to probe the characteristics of inclusions, including their compositions, morphologies, size, number density, and distribution. The results indicate that there were mainly three types of inclusions in 95CrMo steel billets with 6-18 ppm Ca and 30-100 ppm S: inclusions with single-phased morphology mainly composed of oxides; isolated MnS/CaS-only inclusions; inclusions with multi-phased morphology. The three-dimensional inclusion size distribution suggests that there were more Type-1 inclusions with a small size in low S containing steels. The average diameter of all types of inclusions increased with increasing Ca or S content in 95CrMo steel, indicating that the formation of MnS and CaS coarsened their size. The density distribution of inclusions indicates that the more inclusions there are, the more easily they aggregate and collide. Moreover, it is presumably concluded that the formation of sulfide in the outer layer of oxide inclusions weaken the attraction between oxide inclusions. The equilibrated transformation and formation of inclusions during the cooling process of 95CrMo steel was discussed based on thermodynamic calculation. The equilibrated transformation trajectory of inclusions in 95CrMo steel during the cooling process was Ca2SiO4 + MgO → Ca3MgSi2O8 → Spinel + CaS, which was corresponding to the detected results. The precipitation regular of sulfide was obtained. The formation mechanism for three types of inclusions was discussed.

Coarsening Behavior of Particles in Fe-O-Al-Ca Melts.

The characteristics of particles greatly affect the microstructure and performance of metallic materials, especially their sizes. To provide insight into coarsening phenomena of particles in metallic melts, Fe-O-Al-Ca melt with calcium aluminate particles was selected as a model system. This study uses HT-CSLM, SEM detections and stereological analysis to probe the behavior of particles and their characteristics including size, number density, volume fraction, spreading of particle size, inter-surface distance and distribution of particles. Based on the experimental evidence and calculation of collision, we demonstrate that the coarsening of inclusion particles is not only dependent on the Ostwald growth as studied in previous study, but also on the particle coagulation, and floatation. The collision of particles affects the maximum size of the particles during whole deoxidation process and dominates the coarsening of particles at later stage of deoxidation under the condition without external stirring in Fe-O-Al-Ca melts. The factors influencing collision behaviors and floating properties were also analyzed, which is corresponding to coarsening behavior and change of particle characteristic in the melts with different amounts of Ca addition. Such coarsening mechanism may also be useful in predicting the size of particles in other metallic materials.

Nucleation and Ostwald Growth of Particles in Fe-O-Al-Ca Melt.

Tremendous focus has been put on the control of particle size distribution which effects the grain structure and mechanical properties of resulting metallic materials, and thus nucleation and growth of particles in solution should be clarified. This study uses classical nucleation theory and Ostwald ripening theory to probe the relationship between the compositions of Fe-O-Al-Ca melts and the behavior of particles under the condition of no external stirring. Our experimental data suggest that decreasing the initial Ca addition and Al addition is conductive to the increase of nucleation rate for calcium aluminate particles, which exhibits a same change trend with that predicted from classical nucleation theory. Based on the experimental evidence for particles size distribution in three-dimensional, we demonstrate that Ostwald ripening is the predominate mechanism on the coarsening of particles in Fe-O-Al-Ca melt at early stage of deoxidation under the condition of no external stirring but not at later stage.

A LOV-domain-mediated blue-light-activated adenylate (adenylyl) cyclase from the cyanobacterium Microcoleus chthonoplastes PCC 7420.

Genome screening of the cyanobacterium Microcoleus chthonoplastes PCC 7420 identified a gene encoding a protein (483 amino acids, 54.2 kDa in size) characteristic of a BL (blue light)-regulated adenylate (adenylyl) cyclase function. The photoreceptive part showed signatures of a LOV (light, oxygen, voltage) domain. The gene product, mPAC (Microcoleus photoactivated adenylate cyclase), exhibited the LOV-specific three-peaked absorption band (λmax=450 nm) and underwent conversion into the photoadduct form (λmax=390 nm) upon BL-irradiation. The lifetime for thermal recovery into the parent state was determined as 16 s at 20°C (25 s at 11°C). The adenylate cyclase function showed a constitutive activity (in the dark) that was in-vitro-amplified by a factor of 30 under BL-irradiation. Turnover of the purified protein at saturating light and pH 8 is estimated to 1 cAMP/mPAC per s at 25°C (2 cAMP/mPAC per s at 35°C). The lifetime of light-activated cAMP production after a BL flash was ~14 s at 20°C. The temperature optimum was determined to 35°C and the pH optimum to 8.0. The value for half-maximal activating light intensity is 6 W/m2 (at 35°C). A comparison of mPAC and the BLUF (BL using FAD) protein bPAC (Beggiatoa PAC), as purified proteins and expressed in Xenopus laevis oocytes, yielded higher constitutive activity for mPAC in the dark, but also when illuminated with BL.

Independent recruitment of a flavin-dependent monooxygenase for safe accumulation of sequestered pyrrolizidine alkaloids in grasshoppers and moths.

Several insect lineages have developed diverse strategies to sequester toxic pyrrolizidine alkaloids from food-plants for their own defense. Here, we show that in two highly divergent insect taxa, the hemimetabolous grasshoppers and the holometabolous butterflies, an almost identical strategy evolved independently for safe accumulation of pyrrolizidine alkaloids. This strategy involves a pyrrolizidine alkaloid N-oxygenase that transfers the pyrrolizidine alkaloids to their respective N-oxide, enabling the insects to avoid high concentrations of toxic pyrrolizidine alkaloids in the hemolymph. We have identified a pyrrolizidine alkaloid N-oxygenase, which is a flavin-dependent monooxygenase, of the grasshopper Zonocerus variegatus. After heterologous expression in E. coli, this enzyme shows high specificity for pyrrolizidine alkaloids of various structural types and for the tropane alkaloid atropine as substrates, a property that has been described previously for a pyrrolizidine alkaloid N-oxygenase of the arctiid moth Grammia geneura. Phylogenetic analyses of insect flavin-dependent monooxygenase sequences suggest that independent gene duplication events preceded the establishment of this specific enzyme in the lineages of the grasshoppers and of arctiid moths. Two further flavin-dependent monooxygenase sequences have been identified from Z. variegatus sharing amino acid identities of approximately 78% to the pyrrolizidine alkaloid N-oxygenase. After heterologous expression, both enzymes are also able to catalyze the N-oxygenation of pyrrolizidine alkaloids, albeit with a 400-fold lower specific activity. With respect to the high sequence identity between the three Z. variegatus sequences this ability to N-oxygenize pyrrolizidine alkaloids is interpreted as a relict of a former bifunctional ancestor gene of which one of the gene copies optimized this activity for the specific adaptation to pyrrolizidine alkaloid containing food plants.

Flavin-dependent monooxygenases as a detoxification mechanism in insects: new insights from the arctiids (lepidoptera).

Insects experience a wide array of chemical pressures from plant allelochemicals and pesticides and have developed several effective counterstrategies to cope with such toxins. Among these, cytochrome P450 monooxygenases are crucial in plant-insect interactions. Flavin-dependent monooxygenases (FMOs) seem not to play a central role in xenobiotic detoxification in insects, in contrast to mammals. However, the previously identified senecionine N-oxygenase of the arctiid moth Tyria jacobaeae (Lepidoptera) indicates that FMOs have been recruited during the adaptation of this insect to plants that accumulate toxic pyrrolizidine alkaloids. Identification of related FMO-like sequences of various arctiids and other Lepidoptera and their combination with expressed sequence tag (EST) data and sequences emerging from the Bombyx mori genome project show that FMOs in Lepidoptera form a gene family with three members (FMO1 to FMO3). Phylogenetic analyses suggest that FMO3 is only distantly related to lepidopteran FMO1 and FMO2 that originated from a more recent gene duplication event. Within the FMO1 gene cluster, an additional gene duplication early in the arctiid lineage provided the basis for the evolution of the highly specific biochemical, physiological, and behavioral adaptations of these butterflies to pyrrolizidine-alkaloid-producing plants. The genes encoding pyrrolizidine-alkaloid-N-oxygenizing enzymes (PNOs) are transcribed in the fat body and the head of the larvae. An N-terminal signal peptide mediates the transport of the soluble proteins into the hemolymph where PNOs efficiently convert pro-toxic pyrrolizidine alkaloids into their non-toxic N-oxide derivatives. Heterologous expression of a PNO of the generalist arctiid Grammia geneura produced an N-oxygenizing enzyme that shows noticeably expanded substrate specificity compared with the related enzyme of the specialist Tyria jacobaeae. The data about the evolution of FMOs within lepidopteran insects and the functional characterization of a further member of this enzyme family shed light on this almost uncharacterized detoxification system in insects.

New aminophenoxazinones from a marine Halomonas sp.: fermentation, structure elucidation, and biological activity.

The addition of anthranilic acid to the culture medium of the marine derived Halomonas sp. strain GWS-BW-H8hM completely altered the secondary metabolite pattern relative to the standard conditions. The red-orange color of the culture filtrate extract was the result of the production of 2-aminophenoxazin-3-one (1), chandrananimycin C (5) and three new derivatives of 1 with a previously unknown substitution pattern: 2-amino-, 2-amino-8-benzoyl-, and 2-amino-8-(4-hydroxybenzoyl)-6-hydroxyphenoxazin-3-one (2-4). The compounds were determined to have antibacterial and cytotoxic activities; a mode of action other than DNA intercalation is discussed.