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Complex thin-walled structures are commonly employed in turbine components to improve cooling efficiency. However, thin-walled blades are prone to thermal fatigue failure due to the high thermal stress induced by frequent and abrupt temperature fluctuations during duty cycles. The thermal fatigue behavior of Ni3Al-based single crystal alloy with thin-walled structure during 25 °C ↔ 1000 °C/1100 °C was investigated by combining thermal fatigue tests and finite element simulation. The thermal fatigue demonstrated a significant thickness debit effect, with thermal fatigue property dropping as peak temperature and wall thickness increased. Wall thickness had a more pronounced effect than peak temperature. Visible slip traces were found on the wall thickness surface, and their density was positively correlated with wall thickness. Further investigation revealed that thermal fatigue is primarily driven by the octahedral slip system ({111}), with significant contributions from (111)[101‾] and (1‾1‾1)[101]. Simulations of thermal stress distribution and J-integral at the crack tip during crack initiation and propagation stages indicated that wall thickness influences thermal fatigue properties by affecting thermal stress concentration at the notch and crack tip. Higher peak temperatures increased thermal stress and reduced yield strength, thus diminishing thermal fatigue performance. A thermal fatigue crack propagation prediction model was constructed incorporating Paris' law and the J-integral. The model revealed an unfavorable correlation between material Cj/ nj and both peak temperature/wall thickness, indicating that both factors adversely affect thermal fatigue resistance.

The static recrystallization (SRX) of the designed high γ′-fraction Ni-based single crystal superalloy (SX) AlloyX was investigated. The three-dimensional SRX threshold of AlloyX involves plastic strain – deformation temperature – heat treatment temperature established by isothermal deformation and heat treatment tests. The influence of different dislocation configurations obtained at different deformation temperatures on critical SRX temperature was analyzed. The high-density entangled dislocations were observed to gradually transition into low-angle grain boundaries at heat treatment temperature within the γ-channel, potentially serving as the primary driving force for the SRX of AlloyX. Compared with the lower γ′-fraction SX DD32, it is further determined that the preferential dissolution of the small-sized γ′ in the interdendritic region (IDR) caused by high Al is the important factor that induces the recrystallization to occur preferentially in the IDR of AlloyX rather than the dendrite region (DR).

An interesting phenomenon is found in Nickel-based single crystal superalloy thin-wall specimens which have the same [001] primary orientation and different secondary orientation with [100], [210], and [110] at 850 °C. Generally, the testing of cylindrical samples exhibits similar creep and tensile properties regardless of their vertical orientation distribution due to the circumferential symmetry of their geometric structure. However, the 850 °C experimental results of thin-wall specimens with the same [001] primary orientation show a significant difference in tensile ductility and creep life when the secondary orientation is different. The mechanism of the secondary orientation effect is completely discussed by combining experiment, digital image correlation (DIC), and finite element modelling (FEM), which result from the strengthening effect of Lomer-Cottrel dislocations and the ability to coordinate plastic deformation in tensile, the shrinkage rate of cross-section caused by the single slip system ({111} ) and deviation from [001] with a small angle in creep.

BackgroundThe medical knowledge graph provides explainable decision support, helping clinicians with prompt diagnosis and treatment suggestions. However, in real-world clinical practice, patients visit different hospitals seeking various medical services, resulting in fragmented patient data across hospitals. With data security issues, data fragmentation limits the application of knowledge graphs because single-hospital data cannot provide complete evidence for generating precise decision support and comprehensive explanations. It is important to study new methods for knowledge graph systems to integrate into multicenter, information-sensitive medical environments, using fragmented patient records for decision support while maintaining data privacy and security. ObjectiveThis study aims to propose an electronic health record (EHR)–oriented knowledge graph system for collaborative reasoning with multicenter fragmented patient medical data, all the while preserving data privacy. MethodsThe study introduced an EHR knowledge graph framework and a novel collaborative reasoning process for utilizing multicenter fragmented information. The system was deployed in each hospital and used a unified semantic structure and Observational Medical Outcomes Partnership (OMOP) vocabulary to standardize the local EHR data set. The system transforms local EHR data into semantic formats and performs semantic reasoning to generate intermediate reasoning findings. The generated intermediate findings used hypernym concepts to isolate original medical data. The intermediate findings and hash-encrypted patient identities were synchronized through a blockchain network. The multicenter intermediate findings were collaborated for final reasoning and clinical decision support without gathering original EHR data. ResultsThe system underwent evaluation through an application study involving the utilization of multicenter fragmented EHR data to alert non-nephrology clinicians about overlooked patients with chronic kidney disease (CKD). The study covered 1185 patients in nonnephrology departments from 3 hospitals. The patients visited at least two of the hospitals. Of these, 124 patients were identified as meeting CKD diagnosis criteria through collaborative reasoning using multicenter EHR data, whereas the data from individual hospitals alone could not facilitate the identification of CKD in these patients. The assessment by clinicians indicated that 78/91 (86%) patients were CKD positive. ConclusionsThe proposed system was able to effectively utilize multicenter fragmented EHR data for clinical application. The application study showed the clinical benefits of the system with prompt and comprehensive decision support.

With the continuous development of aircraft engine generations, single-crystal alloy blades with more complex shapes and reduced wall thickness are urgently requested. However, the deteriorated performance associated with the wall thickness reduction has not been effectively resolved until now. In this research, the creep behavior of a [001]-oriented Ni3Al-based single crystal alloy with a thin-wall thickness was explored under the environment of 980 °C/220 MPa. A multi-factor coupling mechanism was proposed to explain the premature failure of the thin-walled specimen, providing a comprehensive understanding of the reasons behind the occurrence of the thickness debit effect. The study elucidated the influences of surface oxidation, the stress state of TCP phases, pore growth, and crack propagation on the creep performance. The findings serve as valuable theoretical references for the design and related research of future blade materials.

Designing single-crystal superalloy blades to thin wall structures produces the secondary orientation which is the perpendicularity orientation of the wall surface, becoming a newly-concerned crucial factor of performance. Here, we have studied the influence of [110] and [112] secondary orientations on 1100 °C/137 MPa creep properties of [111]-orientated single-crystal superalloys. The plastic deformation accumulation and the plastic limit during creep vary with secondary orientations. Our results give microstructural evidence of the change in the slip systems operation and micro-pore growth, and correlate the possible stress state in the thin wall to plastic deformation mechanism, and finally to properties, which can explain such influence. The results show that the activation of slip systems with different secondary orientations is different due to the different shear stress, and this difference of slip systems causes the difference of plastic deformation ability and pore growth and finally affects the creep performance.

Diversity-oriented synthesis of 2-pyridone and uracil derivatives is in urgent need in medicinal chemistry as they are useful pharmacophores. Here the authors show that palladium/norbornene cooperative catalysis enabled dual-functionalization of iodinated 2- pyridones and uracils.

With the complexity of the structure of aero-engine turbine blades, the blade wall thickness continues to decrease. It is found that when the blade wall thickness decreases to a certain extent, its mechanical properties will decline significantly. It is extremely important to study this phenomenon of a significant decline in mechanical properties caused by wall thickness. In this paper, the creep behavior of a second-generation Ni3Al-based single crystal superalloy with different wall thicknesses and [001] orientation at 980 °C/220 MPa has been studied and compared with the creep life of Φ4 round bar. The experimental results show that the second orientation and the surface affected zone are not the main reasons for the reduction of the life of thin-walled samples under this experimental condition. By analyzing the fracture morphology and deformed microstructure of thin-walled samples with different thicknesses, it is found that the thickness debit effect of the single crystal alloy occurs since the effective stress area of the alloy changes due to internal defects and surface affected zone during the creep process. For thicker samples, the creep life of the alloy can be extended by making the samples undergo certain plastic deformation through better plastic deformation coordination ability, while for thinner samples, the plastic coordination ability is poor, and the ability to extend the creep life through plastic deformation is also weaker when the effective stress area of the alloy changes, which leads to the thinner samples being more prone to fracture.

Slowing down the coarsening of the γ′ phase and suppressing the precipitation of the topologically close-packed (TCP) phase is crucial for optimizing the creep properties of Ni-based single crystal superalloys, which are affected by the solution treatment history. In the present study, the effect of cooling rate on the morphology, size and lattice misfit of γ′ reprecipitates after solution treatment, as well as the microstructural evolution (e.g., the coarsening of γ′ reprecipitate and precipitation of the TCP phase) and creep properties of samples under different cooling rates at 1100 °C were investigated. The findings suggested that as the cooling rate increasing, the size of γ′ reprecipitates decreased, while the morphology transformed from polygonal to cubic. Additionally, faster cooling rate, on the one hand, the lower the degree of lattice misfit of γ/γ′ phases, which is beneficial to slow down the coarsening of the γ′ phase; on the other hand, the supersaturation of the γ-phase was reduced, i.e., the Mo and Re contents in the γ matrix were lower compared to the slow-cooling sample, which led to a lower TCP phase area fraction during thermal exposure at 1100 °C. It is crucial that the creep life of the alloy significantly improved by increasing the cooling rate after solution treatment; this is facilitated by the formation of rafts from finer cubic γ′ phase and reduction in the TCP phase as a source of microcracks. In conclusion, the findings of this study provide new insights into suppressing the precipitation of the TCP phase and optimizing alloy heat treatment processes to improve creep properties.

C19 hydroxylation is a unique feature of some bioactive steroids. Here, the authors developed a direct C19 hydroxylation approach to scalably access 19-OH-cortexolone in the host T. cucumeris and then converted the product into various pharmaceutically useful products via chemical synthesis.

The hollow twin-web disk is designed to improve the thrust-to-weight ratio of the aero engine, where the welding joint microstructures determine the disk’s mechanical properties. This study aimed to elucidate the effect of abnormal grains formed in the welding region on the mechanical properties of FGH96 solid-state diffusion bonding joints. Digital image correlation using images captured by scanning electron microscopy (SEM-DIC) and electron backscattering diffraction (EBSD) technologies were applied. The results show that abnormally large grains (2.5 times that of the matrix), with preferred orientation in the bonding region, were detrimental to the joint mechanical properties. The yield and tensile strengths were 995.85 MPa and 1456.67 MPa, respectively, and the corresponding relative (ratio to the matrix) ones were 92.54% and 88.81%. After modifying the bonding process, the grain size in the bonding region was tailored to close to that of the matrix, and considerable twin boundaries (TBs) formed, leading to the relative tensile and yield strength reaching 98.86% and 99.37%. Furthermore, the failure mode changed to intragranular type from intergranular type. It demonstrates that tailoring the newborn grain size, introducing TBs inside, and eliminating preferred orientation during the welding process can be an efficient way to improve the joint mechanical properties.

Objectives: Our goal was to investigate the relationship between keloid and telomerase as well as clarifying the influence of Wnt/β-catenin signaling on keloid cell proliferation. Methods: Tissues from 18 keloid patients were collected for further study. Keloid progenitor cells (KPC) and skin progenitor cells (SKP) were both included in this study. Lenti-virus transfection was used to divide cells into different groups in which cells were treated with different substances: negative control (NC) group, wnt10a siRNA group, β-catenin siRNA group and TERT siRNA group. KPC cells were injected into 20 male BALB/c nude mice in order to build tumor models. Several experiments including immunohistochemistry, western blot and RT-PCR were conducted in order to detect the corresponding protein expressions and relative mRNA levels. MTT assay and flow cytometry were also conducted for assessing cell proliferation and apoptosis status. Results: β-catenin and telomerase expression levels in keloid tissues were elevated compared to normal tissues (all P P P Conclusions: Wnt/β-catenin signaling pathway is able to exacerbate keloid cell proliferation and inhibit the apoptosis of keloid cells through its interaction with telomerase.

Objective: To study the association between ADAM33 and keloid scars in the northeastern Chinese population. Methods: A total of 283 keloid scar patients and a control group of 290 healthy volunteers were recruited for this study. Six polymorphic loci (V4, T+1, T2, T1, S2 and Q-1 ) of ADAM33 were selected for genotyping. Genotypes were determined by using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Results: We observed the frequency of the rs612709 A allele exhibited a significantly decreased frequency in cases than in controls(22 vs.39.6%, PP= 0.041). In contrast, the haplotype H8 (GGGAGG) was more common in the control group than in the case group (P=0.022). Conclusions: Our data suggest that the ADAM33 polymorphisms may be associated with keloid scars in the northeastern Chinese population.

Aim: to investigate the association between vitamin D receptor polymorphisms and circulating 1,25-Dihydroxyvitamin D (1,25(OH)2D) levels with keloid scar (KS) risk. Methods: A total of 261 patients with KS and 261 normal healthy individuals were enrolled. VDR gene polymorphisms were determined. Circulating 1,25(OH)2D levels were detected. Results: In this study, we investigated the role of four loci of VDR gene polymorphisms in determining the risk of KS in a Chinese cohort. We found that the TaqI C>T polymorphism was closely associated with the KS incidence. Carriers with CC genotype of TaqI had a higher chance of developing KS. Stratification analyses by sex showed that this trend exists only in female subjects but not in male subjects. Furthermore, the TaqI C>T polymorphism affects the circulating 25-Hydroxyvitamin D levels. The CC carriers had a significantly lower mean circulating 1,25(OH)2D level than TT carriers and CT carriers. KS subjects had significantly lower mean serum circulating 1,25(OH)2D level than controls. The receiver operating characteristic curve analysis revealed that the serum circulating 1,25(OH)2D level at the cut-off point of 16.1 ng/ml could discriminate KS subjects from controls. Conclusion: Collectively, these data provide evidence that the vitamin D/VDR pathway plays an important role in the development of KS. The TaqI gene polymorphisms of VDR and circulating 1,25(OH)2D levels may thus be used as potential markers for prediction of KS development.

Herein, we report an asymmetric two-component alkenyl Catellani reaction for the construction of C--N axial chirality through a palladium/chiral norbornene cooperative catalysis and an axial-to-axial chirality transfer process. Various partially aromatic iodinated 2-pyridones, quinolones, coumarin and uracil substrates react with 2,6-disubstituted aryl bromides with a tethered amide group, to afford a wide variety of polycyclic C--N atropisomers (38 examples, up to 97% e.e.). The obtained C--N axial chirality originates from the preformed transient C--C axial chirality with high fidelity. The synthetic utility of this chemistry is demonstrated by facile preparation of complex quinoline and pyridine based C--N atropisomers through a N-deprotection and aromatization sequence. In addition, a remote axial-to-central diastereoinduction process dictated by C--N axial chirality is observed with excellent diastereocontrol. [ABSTRACT FROM AUTHOR]