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At high cutting speeds, the internal microstructure of the difficult-to-machine material Inconel 718 will change. Alterations in the internal microstructure lead to macroscopic deformations, which in turn result in the formation of adiabatic shear bands. In order to better study the formation of adiabatic shear bands during cutting Inconel 718, cutting experiments, SHPB experiments, and finite element simulations were carried out. The stored energy model for adiabatic shear bands was developed by combining the overall dislocation density and the variation of the stress field in this paper. Based on the strain gradient theory, the subroutine was compiled for secondary development to achieve multi-scale finite element simulation that can visualize the stored energy. The experiment and simulation results were combined to derive the change in stress, temperature, and overall dislocation density and to analyze the adiabatic shear bands storage energy based on the change. The analytical results are also combined with dynamic recrystallization and periodic fracture theories to characterize the formation mechanism of adiabatic shear bands. It was found that the overall dislocation density, stress, and adiabatic shear bands storage energy follow the same trend, while the temperature and shear zone storage energy follow opposite trends. [ABSTRACT FROM AUTHOR]

Electrochemical micromachining (EMM) has become a popular technology for fabricating microscale structures. To obtain higher machining localization and minor stray corrosion, a new hybrid EMM process combining air assistance and ultrasonic assistance was introduced in this paper. Simulations and experimental investigations were conducted to study the influencing mechanism and the influencing characteristics of the assisting process energies. In the multi-physics model, a reactant transport model is included, and the direct coupling between the assisting processes and the electrochemical process is achieved. Results indicate that, when the two assisting processes are applied separately, the assisting effect tend to act on the entire workpiece surface, either promotes the overall dissolution or inhibits it, usually leading to unsatisfactory results; by combining the two assisting processes, synergistic effect occurs: dissolution in the central area is promoted by the ultrasonic assistance, while stray corrosion in the margin area is hindered by the air assistance. Thus, microstructures with enhanced aspect ratio and reduced stray corrosion can be fabricated. The results also show that the surrounding airflow can produce an electrical insulating effect on both the workpiece and the cathode. When the air pressure is low, an additional concentrating effect on the electric field can be observed; however, a high air pressure leads to a greatly hindered dissolution. When the applied amplitude is appropriate, ultrasonic assistance promotes the electrochemical dissolution through disturbance effect and cavitation phenomena. But if the amplitude is too large, massive cavitation bubbles will inhibit the dissolution greatly. [ABSTRACT FROM AUTHOR]

Human brain connectomes include sets of densely connected hub regions. However, the consistency and reproducibility of functional connectome hubs have not been established to date and the genetic signatures underlying robust hubs remain unknown. Here, we conduct a worldwide harmonized meta-connectomic analysis by pooling resting-state functional MRI data of 5212 healthy young adults across 61 independent cohorts. We identify highly consistent and reproducible connectome hubs in heteromodal and unimodal regions both across cohorts and across individuals, with the greatest effects observed in lateral parietal cortex. These hubs show heterogeneous connectivity profiles and are critical for both intra- and inter-network communications. Using post-mortem transcriptome datasets, we show that as compared to non-hubs, connectome hubs have a spatiotemporally distinctive transcriptomic pattern dominated by genes involved in the neuropeptide signaling pathway, neurodevelopmental processes, and metabolic processes. These results highlight the robustness of macroscopic connectome hubs and their potential cellular and molecular underpinnings, which markedly furthers our understanding of how connectome hubs emerge in development, support complex cognition in health, and are involved in disease.A worldwide harmonized meta-connectomic analysis of 5212 healthy young adults across 61 independent cohorts provides consistent, reproducible, and transcriptionally relevant functional connectome hubs in the resting human brain. [ABSTRACT FROM AUTHOR]

Rapidly mutating Y-STRs (RM Y-STRs) harbor great potential to distinguish male relatives and achieve male identification. However, forensic applications were greatly limited by the small number of the initially identified 14 RM Y-STRs. Recently, with the emergence of 12 novel RM Y-STRs, an integrated panel named RMplex was introduced, which contains all 26 RM Y-STRs and four fast mutating Y-STRs (FM Y-STRs). To obtain the first data on the mutation rates and father-son differentiation rates of the 30 newly proposed Y-STRs in Chinese populations, we performed an empirical mutation study on 307 DNA-confirmed Chinese paternal pairs. Previously reported mutation rates for 14 RM Y-STRs in Chinese and European populations were pooled and merged with our data. The highest meiosis number for the two groups reached 4771 and 2687, respectively. Five loci showed significant differences between the populations (DYS570, DYS399S1, DYS547, DYS612, and DYF403S1b). For the new panel covering 30 Y-STR loci, our results show extensive differences in the mutation rates between the two populations, as well. 10 RM Y-STR loci showed relatively low mutation rates (10–3–10–2 per meiosis) and 2 FM Y-STR loci had rapid mutation rates (> 10–2 per meiosis) in the Chinese population. Several-fold differences in mutation rates were found in nine Y-STR loci between the Chinese and reference populations, with two loci having significantly higher mutation rates and one locus with a significantly lower mutation rate in the Chinese population (P < 0.05). Eighteen RM Y-STRs (> 10–2 per meiosis), 8 FM Y-STR loci (5×10–3-10–2 per meiosis), 3 moderately mutating Y-STRs (MM Y-STRs, 10–3-5×10–3 per meiosis), and one locus with no observed mutation events were identified in the Chinese population. 40.06% of the Chinese paternity pairs were discriminated with RMplex while only 20.84% with the initial 14 RM Y-STRs, indicating that RMplex is beneficial for distinguishing paternally related males. Future studies on populations of different genetic backgrounds are necessary to obtain comprehensive estimates of mutation rates at these new loci. [ABSTRACT FROM AUTHOR]

Micro-structure on metal surface can be created with high precision and good surface quality by ultrasonic-assisted electrochemical micromachining (USEMM). One of the prevalent material removal mechanisms in ultrasonic machining (UM) is cavitation erosion. However, the mechanism of material erosion is not clear and worth investigating. This study of the mechanical and chemical effects of the ultrasonic vibration on the 6061 aluminum alloy is targeted to reveal the material processing mechanism in USEMM. Based on the built model, the velocity of micro-jet produced near the workpiece surface by ultrasonic cavitation reaches up to 350 m/s when bubble collapses computed by software MATLAB. The impact of micro-jet produces plastic micro-pits on the metal surface and the convex peak around the edge of the pits, which is verified in ABAQUS software. The metallographic microscope and curves of the electrochemical polarization behavior results indicate a significant grain refinement and a marked increase of anodic dissolution current, as well as a weaker resistance than the original workpiece in NaNO3 electrolyte during UM. The current-time curve during machining demonstrates the passive layer forms on the metal surface and then breaks down at the time of less than 0.0066s in USEMM. Micrographs of scanning electron microscope (SEM) of the machined surface in different stages show that many uniform and flat pits are formed in USEMM, compared with the local uneven pits in EMM. [ABSTRACT FROM AUTHOR]

Introduction: Cancer patients are prone to infections, but the mortality of fatal infections remains unclear. Understanding the patterns of fatal infections in patients with cancer is imperative. In this study, we report the characteristics, incidence, and predictive risk factors of fatal infections among a population-based cancer cohort. Methods: A total of 8,471,051 patients diagnosed with cancer between 1975 and 2016 were retrospectively identified from the Surveillance, Epidemiology, and End Results (SEER) program. The primary outcome was dying from fatal infections. Mortality rates and standardized mortality ratios (SMRs) adjusted for age, sex, race, and calendar year were calculated to characterize the relative risks of dying from fatal infections and to compare with the general population. Furthermore, cumulative mortality rates and the Cox regression models were applied to identify predictive risk factors of fatal infections. Results: In cancer patients, the mortality rate of fatal infections was 260.1/100,000 person-years, nearly three times that of the general population [SMR, 2.92; 95% (confidence interval) CI 2.91–2.94]. Notably, a decreasing trend in mortality rate of fatal infections was observed in recent decades. SMRs of fatal infections were highest in Kaposi sarcoma (SMR, 162.2; 95% CI 159.4–165.1), liver cancer (SMR, 30.9; 95% CI 30.0–31.8), acute lymphocytic leukemia (SMR, 19.1; 95% CI 17.0–21.4), and acute myeloid leukemia (SMR, 13.3; 95% CI 12.4–14.3). Patients aged between 20 and 39 years old exhibited a higher cumulative mortality rate in the first few years after cancer diagnosis, whereas the cumulative mortality rate of those > 80 years old was rapidly increasing and became the highest approximately 3 years post-cancer diagnosis. Predictive risk factors of dying from fatal infections in cancer patients were the age of 20–39 or > 80 years, male sex, black race, diagnosed with cancer before 2000, unmarried status, advanced cancer stage, and not receiving surgery and radiotherapy, but receiving chemotherapy. Conclusion: Cancer patients were at high risks of dying from infectious diseases. Certain groups of cancer patients, including those aged between 20 and 39 or > 80 years, as well as those receiving chemotherapy, should be sensitized to the risk of fatal infections. [ABSTRACT FROM AUTHOR]

Microdimples as a typical surface texture has been widely used for improving the properties in tribology and heat transfer fields. Ultrasonically assisted electrochemical micromachining (USEMM) is a popular method for generating microdimples as it can reduce the overcutting and enhance electrolyte renewal to improve the machining localization and promote the material removal. However, the fundamental understanding of the process and particularly the relationship between the machining performance and gap pressure is limited. In this paper, radial ultrasonicrolling electrochemical micromachining (RUREMM) is employed to generate microdimples on SS304 surface. Effects of gap pressure on the material removal rate, machining accuracy, and roughness are studied and discussed in detail. Results show that RUREMM can fabricate the microdimples and the existing ultrasonic vibration in the inter-electrode gap is more effective to enhance the machining performance. By using the selected parameters in RUREMM, the current density during machining has a 6.6% increase in RUREMM than in EMM. Moreover, the width of the microdimple is decreased by 14.6%, the depth of the microdimple is increased by 19.2%, the cross-sectional area of the machined dimple is expanded by 31.2%, the roughness of the bottom is decreased 23.9% and also, better surface quality for the side wall could be obtained. [ABSTRACT FROM AUTHOR]

Nanostructured gold substrates provide chemically stable, signal-enhancing substrates for the sensitive detection of a variety of compounds through surface-enhanced Raman spectroscopy (SERS). Recent developments in advanced fabrication methods have enabled the manufacture of SERS substrates with repeatable surface nanostructures that provide reproducible quantitative analysis, historically a weakness of the SERS technique. Here, we describe the novel use of gold-sputtered Blu-ray disc surfaces as SERS substrates. The unique surface features and composition of the Blu-ray disc recording surface lead to the formation of gold nano-islands and nanogaps following simple gold sputtering, without any background peaks from the substrate. The SERS performance of this substrate is strong and reproducible with an enhancement factor (EF) of 10 for melamine. A limit of detection (LOD) for this compound of 70 ppb and average reproducibility of ±12 % were achieved. Gold-sputtered Blu-ray discs thus offer an excellent alternative to more exotic gold SERS substrates prepared by advanced, time-consuming and expensive methods. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]