Fatigue crack propagation behavior of Ni-based superalloys after overloading at elevated temperatures

AbstractThe fatigue crack propagation behavior of three superalloys subjected to a single overloading at elevated temperatures was investigated. The fatigue crack propagation rate FCPR versus stress intensity factor range data da/dN—ΔK were calculated using the two-point secant method. It was found that the crack growth rates of the investigated materials were retarded after overloading with an overload ratio ROL=1.6. The size of the plastic zone in the front of the crack tip and its relation to loading level were discussed. The overload retardation effects are attributed to crack closure. The fatigue damage in the plastic zone can also be a factor to explain the overload retardation

Communication-efficient federated learning for digital twin systems of industrial internet of things

With the rapid development and deployment of Industrial Internet of Things technology, it promotes interconnection and edge applications in smart manufacturing. However, challenges remain, such as yet-to-improve communication efficiency and trade-offs between computing power and energy consumption, which limits the application and further development of IIoT technology. This paper proposes the digital twin systems into the IIoT to build model between physical objects and digital virtual systems to optimize the structure of IIoT. And we further introduce federal learning to train the digital twins model and to improve the communication efficiency of IIoT. In this paper, we first establish the digital twins model of IIoT based on industrial scenario. Moreover, to optimize the communication overhead allocation problem, this paper proposes an improved communication-efficient distribution algorithm, which speeds up the training performance of federated model and ensures the performance of industrial system model by changing the update training mode of client and server and allowing some industrial equipment to participate in federated training. This paper simulates the real-word intelligent camera detection to validate the proposed method. Comparing our proposed method with the existing traditional methods, the results show the advantages of the proposed method can improve the communication performance of the training model

Detection of Pancreatic Carcinomas by Imaging Lactose-Binding Protein Expression in Peritumoral Pancreas Using [18F]Fluoroethyl-Deoxylactose PET/CT

BACKGROUND: Early diagnosis of pancreatic carcinoma with highly sensitive diagnostic imaging methods could save lives of many thousands of patients, because early detection increases resectability and survival rates. Current non-invasive diagnostic imaging techniques have inadequate resolution and sensitivity for detection of small size ( approximately 2-3 mm) early pancreatic carcinoma lesions. Therefore, we have assessed the efficacy of positron emission tomography and computer tomography (PET/CT) imaging with beta-O-D-galactopyranosyl-(1,4')-2'-deoxy-2'-[(18)F]fluoroethyl-D-glucopyranose ([(18)F]FEDL) for detection of less than 3 mm orthotopic xenografts of L3.6pl pancreatic carcinomas in mice. [(18)F]FEDL is a novel radioligand of hepatocarcinoma-intestine-pancreas/pancreatitis-associated protein (HIP/PAP), which is overexpressed in peritumoral pancreatic acinar cells. METHODOLOGY/PRINCIPAL FINDINGS: Dynamic PET/CT imaging demonstrated rapid accumulation of [(18)F]FEDL in peritumoral pancreatic tissue (4.04+/-2.06%ID/g), bi-exponential blood clearance with half-lives of 1.65+/-0.50 min and 14.14+/-3.60 min, and rapid elimination from other organs and tissues, predominantly by renal clearance. Using model-independent graphical analysis of dynamic PET data, the average distribution volume ratio (DVR) for [(18)F]FEDL in peritumoral pancreatic tissue was estimated as 3.57+/-0.60 and 0.94+/-0.72 in sham-operated control pancreas. Comparative analysis of quantitative autoradiographic images and densitometry of immunohistochemically stained and co-registered adjacent tissue sections demonstrated a strong linear correlation between the magnitude of [(18)F]FEDL binding and HIP/PAP expression in corresponding regions (r = 0.88). The in situ analysis demonstrated that at least a 2-4 fold apparent lesion size amplification was achieved for submillimeter tumors and to nearly half a murine pancreas for tumors larger than 3 mm. CONCLUSION/SIGNIFICANCE: We have demonstrated the feasibility of detection of early pancreatic tumors by non-invasive imaging with [(18)F]FEDL PET/CT of tumor biomarker HIP/PAP over-expressed in peritumoral pancreatic tissue. Non-invasive non-invasive detection of early pancreatic carcinomas with [(18)F]FEDL PET/CT imaging should aid the guidance of biopsies and additional imaging procedures, facilitate the resectability and improve the overall prognosis

Prognostic significance of tumor volume in locally recurrent nasopharyngeal carcinoma treated with salvage intensity-modulated radiotherapy.

INTRODUCTION:To evaluate the prognostic value of gross tumor volume (TV) in patients with locally recurrent, nonmetastatic nasopharyngeal carcinoma. METHODS:Between 2001 and 2012, 291 consecutive patients with locally recurrent, nonmetastatic nasopharyngeal carcinoma underwent salvage IMRT were retrospectively reviewed. The correlations between TV and recurrent T classification were analyzed. Survival analyses were performed. Receiver operating characteristic (ROC) curves were calculated to identify cut-off point of TV. The Akaike information criterion and Harrell's concordance index (c-index) were utilized to test the prognostic value. RESULTS:The median TV significantly increased with advancing recurrent T classification (P<0.001). The 5-year overall survival rate was 33.2% for the entire cohort. On multivariate analysis, TV was an independent negative prognostic factor for distant metastasis-free survival (hazard ratio =1.013, P =0.003), overall survival (hazard ratio = 1.015, P<0.001) and toxicity-related death (hazard ratio = 1.014, P<0.001). The 5-year overall survival rates were 63.1% and 20.8% for patients with a TV < 22 cm3 and TV ≥22 cm3, respectively (P < 0.001). In patient with TV <22 cm3, locoregional failure is the leading cause of death. In patients with TV≥22 cm3, distant metastasis rate is higher and occurred within short term after local recurrence; meanwhile, radiation-induced injuries became more common and led to half of deaths in this group. The Akaike information criterion and c-index analyses indicated that the predictive ability of recurrent T classification improved when combined with TV. CONCLUSIONS:Our data suggests TV is a significant prognostic factor for predicting the distant metastasis, overall survival and toxicity-related death of patients with locally recurrent, nonmetastatic nasopharyngeal carcinoma after salvage IMRT. TV should be considered when designing personalized salvage treatments for these patients. For patients with bulky local recurrent tumor, radiation may need to be de-emphasized in favor of systemic treatment or best supportive care

Interference-assisted kaleidoscopic meta-plexer for arbitrary spin-wavefront manipulation

Fighting interference with interference: Hybrid meta-atoms spin off a kaleidoscope of opportunities Interferences are typically considered useless and even adverse in highly integrated photonic circuits and metasurfaces. The approach from Cheng-Wei Qiu from the National University of Singapore and colleagues is to exploit interference between hybrid meta-atoms based on pairs of nested microscale rings, each with a small opening. With this counterintuitive recipe, they successfully reported multiplexed functions, i.e., emission of complex vortices and diode-like optical switching devices that manipulates spin lights. By using computer simulations to examine the effects of optical scattering with differently-oriented split rings in periodic arrays, the team identified interference patterns that offered simultaneous control over the helical spin and propagation of circularly polarized light. One proposed metasurface produces narrow beams with pure spin-down states that may have applications in optical tweezing or stealth technology. Another layout generates multiple swirling light vortices by filtering to pure spin-up states. It paves an unexpected paradigm to realizing optical diodes, isolators, and spin-Hall meta-devices without cascading bulky optical elements

Kaplan-Meier survival curves of the local failure-free survival (A), distant metastasis-free survival (B), overall survival (C) and toxicity-related death (D) of all 291 locally recurrent nasopharyngeal carcinoma patients.

<p>Kaplan-Meier survival curves of the local failure-free survival (A), distant metastasis-free survival (B), overall survival (C) and toxicity-related death (D) of all 291 locally recurrent nasopharyngeal carcinoma patients.</p

Stratified analyses of all 291 locally recurrent nasopharyngeal carcinoma patients using the gross recurrent tumor volume (TV) cut-off point (<22 cm³ vs. ≥22 cm³) to compare overall survival (A), local failure-free survival (B), distant metastasis-free survival(C) and toxicity-related death (D).

<p>Stratified analyses of all 291 locally recurrent nasopharyngeal carcinoma patients using the gross recurrent tumor volume (TV) cut-off point (<22 cm³ vs. ≥22 cm³) to compare overall survival (A), local failure-free survival (B), distant metastasis-free survival(C) and toxicity-related death (D).</p