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Laser deposition manufacturing (LDM) technology provides the potential to manufacture large, difficult-to-process metal components for aerospace and other applications. However, the residual stresses resulting from the considerable temperature gradients in the LDM process can lead to distortion and even cracking of the fabricated components. Rapidly predicting the distortion for large additive metal components is critical to controlling the distortion and achieving high-quality forming of large components. Considering the principle of LDM technology, the partitioning method based on typical geometric features for aerospace titanium alloy frames, beams, and wall plates is proposed in this paper. It establishes a rapid prediction method for distortion of large additive metal components based on feature partitioning and temperature function method (TFM) by considering the effect of critical parameters of temperature function on distortion prediction. The results show that the prediction of additive component distortion through this method agrees with the results predicted by the traditional method and experimental results. Furthermore, the computational efficiency of the method has improved by 96% compared to the traditional approach, meeting the need for rapid distortion prediction in large metal additive components. [ABSTRACT FROM AUTHOR]

The compression behavior of a damaged I-section stiffened panel repaired by the bolted metal patch method is studied experimentally and numerically by the finite element method in this paper. In the finite element model, the bolt was simulated by a combination of beam elements coupled to rigid contact surfaces, the coupling failure criterion and a new delamination criterion were used to analyze the failure of composite laminates and bonding interfaces, respectively. The repairing effects of the mechanical fastening method are compared with the panels with damage. The results show that the load-carrying capacity of the repaired panel increases significantly compared with the panel with damage. The experimental results validate the proposed finite element model. Finally, an improved repair configuration is proposed based on the finite element simulation. This shows that the presented repair is useful and effective to repair the damaged composite structures. [ABSTRACT FROM AUTHOR]

This paper presents a micromechanical method to analyze the thermal stresses in a finite plane containing multiple elliptical inclusions. Firstly, the Eshelby's equivalent inclusion method is employed to solve the elastic fields of a two-dimensional infinite plane containing multiple elliptical inclusions under a uniform temperature change. Both the interior Eshelby's tensor and the exterior Eshelby's tensor are employed. Then the boundary of the plane is modeled by continuous distributions of dislocation densities. By combining the two steps, a system of singular integral equations is formulated based on the traction-free boundary condition. Then the thermal stresses of the plane can be obtained by the superposition of the stresses obtained by the Eshelby's equivalent inclusion method and distributed dislocation method. Additionally, some examples are given to show the effects of the presented method. The effects of the material constants, geometric parameters and fiber packing arrangement on the thermal stresses are also studied. [ABSTRACT FROM AUTHOR]

This paper presents an automatic fatigue crack propagation solution for particulate-reinforced composites. In this solution, the Eshelby's equivalent inclusion method is used to solve the elastic fields of a two-dimensional plane containing multiple elliptical inclusions. Then the continuous distributed dislocations in an infinite plane are adopted to model the multiple cracks in the plane containing multiple elliptical inclusions. By combining the two methods, a system of singular integral equations can be formulated based on the stress condition of the cracks. The stress intensity factor of each crack can be obtained by solving the singular integral equations. The propagation of the cracks is studied based on the maximum circumferential stress criterion. Numerical examples are presented to show the complicated changes in the stress intensity factors and crack growth behaviors of the cracks affected by the inclusions. [ABSTRACT FROM AUTHOR]

Natural images contain often curvilinear structures, which might be disconnected, or partly occluded. Recovering the missing connection of disconnected structures is an open issue and needs appropriate geometric reasoning. We propose to find line co-occurrence statistics from the centerlines of blood vessels in retinal images and show its remarkable similarity to a well-known probabilistic model for the connectivity pattern in the primary visual cortex. Furthermore, the probabilistic model is trained from the data via statistics and used for automated grouping of interrupted vessels in a spectral clustering based approach. Several challenging image patches are investigated around junction points, where successful results indicate the perfect match of the trained model to the profiles of blood vessels in retinal images. Also, comparisons among several statistical models obtained from different datasets reveal their high similarity, i.e., they are independent of the dataset. On top of that the best approximation of the statistical model with the symmetrized extension of the probabilistic model on the projective line bundle is found with a least square error smaller than $$2\%$$ . Apparently, the direction process on the projective line bundle is a good continuation model for vessels in retinal images. [ABSTRACT FROM AUTHOR]

This paper presents a numerical solution to calculate the two-dimensional elastic fields of a finite plate containing a circular inclusion. The boundaries of the plate are modeled by distributed dislocations. This method results in a system of singular integral equations with Cauchy kernels which can be solved by Gauss-Chebyshev quadrature method. The elastic fields of the plate can be solved with the integral along the whole boundary which is modeled by distributed dislocations. Several numerical examples are given to assess the performance of the presented method. [ABSTRACT FROM AUTHOR]

The intermittent cutting behavior, performing as periodic contact phase and separation phase between abrasive grit and workpiece, is an important characteristic in the ultrasonic vibration-assisted grinding (UVAG). This study investigated the effect of intermittent cutting behavior on the grinding force in UVAG. At first, a grinding force model was established by determining the quantity of effective grits and the grinding force of a single grit. Then, the influences of ultrasonic vibration phase on the intermittent cutting behavior and grinding force were discussed. Finally, the prediction accuracy of the model was tested through experiments. Results indicated that the intermittent cutting behavior was divided into the contact phase and separation phase. A large unchanged chip thickness of 1.05 μm was generated at the start of contact phase. The quantity of effective grits firstly increased to maximum 232 at the vibration phase of 0.5 π and then gradually decreased to zero when entering the separation phase. The maximum error of the grinding force model was 15%, indicating that the model was of high accuracy for the force prediction in UVAG. [ABSTRACT FROM AUTHOR]

Purpose: This study was conducted in order to investigate the topological organization of functional and structural brain networks in diabetic kidney disease (DKD) and its potential clinical relevance. Methods: Two hundred two subjects (62 DKD patients, 60 diabetes mellitus [DM] patients, and 80 healthy controls) underwent laboratory examination, neuropsychological test, and magnetic resonance imaging (MRI). Large-scale functional and structural brain networks were constructed and graph theoretical network analyses were performed. The effect of renal function on brain functional and structural networks in DKD patients was further evaluated. Correlations were performed between network properties and neuropsychological scores and clinical variables. Results: Progressing deteriorated global and local network topology organizations (especially for functional network) were observed for DKD patients compared with control subjects (all p < 0.05, Bonferroni-corrected), with intermediate values for the patients with DM. DKD patients showed normally appearing functional–structural coupling compared with controls, while DM patients manifested functional–structural decoupling (p < 0.05, Bonferroni-corrected). Impaired kidney function markedly affected functional and structural network organization in DKD patients (all p < 0.05). Urea nitrogen correlated with global and local efficiency in the structural networks (r = − 0.551, p < 0.001; r = − 0.476, p < 0.001, respectively). Global and local efficiency in the structural networks and normalized characteristic path length in the functional networks were associated with information processing speed and/or psychomotor speed. Conclusion: DKD patients showed enhanced functional and structural brain network disruption and normally appearing functional–structural coupling compared with DM patients, which correlated with kidney function, renal toxins, and cognitive performance. Key Points: • DKD patients showed markedly disrupted functional and structural brain network efficiency measures compared with DM patients and healthy controls. • Reduced kidney function clearly deteriorated functional and structural brain networks in DKD patients. • DKD patients displayed normally appearing functional–structural coupling compared with DM patients. [ABSTRACT FROM AUTHOR]

Background: Alpha-defensin, a novel biomarker, has shown great potential for the accurate diagnosis of periprosthetic joint infection (PJI) in recent years: many published studies have presented encouraging results. Nevertheless, the diagnostic accuracy of alpha-defensin is inconsistent across published studies. Moreover, the optimum value of the diagnostic threshold urgently needs to be ascertained. This meta-analysis sought to estimate the precision of alpha-defensin for the diagnosis of PJI and, where possible, to confirm the threshold.Method: We systematically searched PubMed, Embase, Cochrane, Web of Knowledge, and ClinicalTrials.gov for relevant literature on alpha-defensin in the diagnosis of PJI (searching publications from the inception of each database until February 2017, with no language restriction). Pooled sensitivity, specificity, diagnostic odds ratios, and likelihood ratios were the indexes used for assessment, with the use of a random-effects model.Result: Eleven of the 426 studies that evaluated the diagnostic accuracy of alpha-defensin in periprosthetic joint infection (PJI) were included in this analysis. The pooled diagnostic sensitivity of alpha-defensin for PJI was 0.96 (95% confidence interval [CI], 0.87 to 0.99) and the specificity was 0.95 (95% CI, 0.91 to 0.97). Since there was substantial heterogeneity among studies, based on the inconsistency index (I2), threshold, site of arthroplasty, study design and techniques for the alpha-defensin test, subgroup analyses were performed to estimate the impacts of these variables on heterogeneity.Conclusion: In summary, this meta-analysis clearly lends support to the conclusion that alpha-defensin is a promising addition to the current methods for diagnosis of PJI. [ABSTRACT FROM AUTHOR]

Aims: Although endoscopic retrograde cholangiopancreatography (ERCP) for large common bile duct (CBD) stones is facilitated by digital cholangioscopy-guided lithotripsy, it is performed by fluoroscopy guidance. Here, we report our experience of non-radiation ERCP for large CBD stones using digital cholangioscopy-guided laser lithotripsy.Methods: Sixteen patients with large CBD stones underwent non-radiation digital cholangioscopy-guided laser lithotripsy and lithotomy. Data relevant to procedure details, adverse events, and short-term follow-up were analyzed.Results: Biliary access was achieved in all patients using standard guidewire-assisted cannulation, double-guidewire technique, and transpancreatic precut in twelve, two, and two patients, respectively. Balloons of 10 mm, 8 mm, and 6 mm in diameter were applied for EPBD in 8, 2, and 6 patients, respectively. Complete stone removal in one session was achieved in all patients. One round of laser lithotripsy was needed for stone ≤ 25 mm, and three-to-five rounds were needed for stones > 25 mm or multiple stones. One or two clips were used for endoscopic clipping. The time lengths of biliary access, digital cholangioscopy-assisted laser lithotripsy and stone extraction, and whole procedure were 3.5 ± 3.2 (0.5-12) minutes, 52.5 ± 30.6 (45-97) minutes, and 76 ± 23.3 (58-106) minutes, respectively. Asymptomatic hyperleukocytose, hyperamylasemia, and mild pancreatitis were present in 1, 2, and 1 patient(s), respectively. No other complications occurred. No cholangitis or recurrent CBD stones were observed.Conclusion: Non-radiation digital cholangioscopy-guided laser lithotripsy is technically feasible and can be safely performed for endoscopic management of large CBD stones. [ABSTRACT FROM AUTHOR]

The objective of the study was to evaluate the characteristics and prognosis of 56 patients with rheumatoid arthritis (RA)-associated renal involvement by retrospective review of their renal biopsy specimens. Included in this cross-sectional study were 56 RA patients with renal involvement, in whom renal biopsy was performed to analyze the histological pattern and renal prognosis. IgA nephropathy (IgAN) was detected in 48.2% of the 56 included patients as the most common renal histological pattern, followed by membranous nephropathy (MN) in 23.2% cases, focal segmental glomerular sclerosis (FSGS) in 19.6% cases, chronic interstitial nephritis (CIN) in 5.4% cases, membranoproliferative glomerulonephritis (MPGN) in 1.8% cases, and non-IgA mesangial proliferative glomerulonephritis in 1.8% cases. No significant relationship was observed between the histopathologic type and the RA duration, joint deformity or treatment. Renal dysfunction was mainly found in IgAN patients, and MN occurred more frequently in older patients. Renal function decline occurred in two IgAN patients, one with FSGS and the other with MPGN. Another CIN patient progressed to dialysis during the follow-up period. The patients with renal function decline had a significantly higher level of serum creatinine at presentation. The high percentage of glomeruli sclerosis and interstitial fibrosis/tubular atrophy was also related to renal function decline. IgAN was the major RA-associated renal histological lesion in our series. Renal biopsy can provide useful information about the histological pattern and renal prognosis and therefore should be considered in RA patients with renal involvement. [ABSTRACT FROM AUTHOR]

Purpose: This study was conducted in order to investigate the topological organization of functional and structural brain networks in diabetic kidney disease (DKD) and its potential clinical relevance.Methods: Two hundred two subjects (62 DKD patients, 60 diabetes mellitus [DM] patients, and 80 healthy controls) underwent laboratory examination, neuropsychological test, and magnetic resonance imaging (MRI). Large-scale functional and structural brain networks were constructed and graph theoretical network analyses were performed. The effect of renal function on brain functional and structural networks in DKD patients was further evaluated. Correlations were performed between network properties and neuropsychological scores and clinical variables.Results: Progressing deteriorated global and local network topology organizations (especially for functional network) were observed for DKD patients compared with control subjects (all p < 0.05, Bonferroni-corrected), with intermediate values for the patients with DM. DKD patients showed normally appearing functional-structural coupling compared with controls, while DM patients manifested functional-structural decoupling (p < 0.05, Bonferroni-corrected). Impaired kidney function markedly affected functional and structural network organization in DKD patients (all p < 0.05). Urea nitrogen correlated with global and local efficiency in the structural networks (r = - 0.551, p < 0.001; r = - 0.476, p < 0.001, respectively). Global and local efficiency in the structural networks and normalized characteristic path length in the functional networks were associated with information processing speed and/or psychomotor speed.Conclusion: DKD patients showed enhanced functional and structural brain network disruption and normally appearing functional-structural coupling compared with DM patients, which correlated with kidney function, renal toxins, and cognitive performance.Key Points: • DKD patients showed markedly disrupted functional and structural brain network efficiency measures compared with DM patients and healthy controls. • Reduced kidney function clearly deteriorated functional and structural brain networks in DKD patients. • DKD patients displayed normally appearing functional-structural coupling compared with DM patients. [ABSTRACT FROM AUTHOR]

Purpose: The aim of the present study was to investigate the long-term outcome and the wear characteristics of two distinct types of ultra-high molecular weight polyethylene (UHMWPE) liners in total hip arthroplasty (THA).Methods: We conducted a retrospective clinical study on patients which were treated with total hip arthroplasty using either Enduron polyethylene (Enduron PE) or Trilogy polyethylene (Trilogy PE) liners based on a minimum of ten year follow up data. Morphological analyses of wear particles from tissue samples, which were harvested during revision surgeries, were also performed.Results: A total of 79 THAs in the Enduron group and 55 THAs in the Trilogy group were available for analysis. Kaplan-Meier survival with revision for wear-related complications as the endpoint of the Enduron PE liners was lower than that of Trilogy PE liners at ten years (93.5 % and 100 %, P = 0.03). The Enduron group had higher mean linear wear rate than that of the Trilogy group (0.20 ± 0.09 and 0.09 ± 0.03 mm/year, P < 0.01). The incidence of osteolysis for the Enduron group was higher than that of the Trilogy group (33.3 % and 12 %, P = 0.04). Under transmission electron microscopy, the Enduron group had more than 82 % of the particles less than 1.0 μm in size and more than 57 % of the particles less than 0.5 μm.Conclusion: The long-term performance of Enduron liners was worse than that of Trilogy liners. Further clinical follow-up may be necessary in patients with Enduron PE liners in order to avoid catastrophic complications. [ABSTRACT FROM AUTHOR]

Retinal image analysis is a challenging problem due to the precise quantification required and the huge numbers of images produced in screening programs. This paper describes a series of innovative brain-inspired algorithms for automated retinal image analysis, recently developed for the RetinaCheck project, a large-scale screening program for diabetic retinopathy and other retinal diseases in Northeast China. The paper discusses the theory of orientation scores, inspired by cortical multi-orientation pinwheel structures, and presents applications for automated quality assessment, optic nerve head detection, crossing-preserving enhancement and segmentation of retinal vasculature, arterio-venous ratio, fractal dimension, and vessel tortuosity and bifurcations. Many of these algorithms outperform state-of-the-art techniques. The methods are currently validated in collaborating hospitals, with a rich accompanying base of metadata, to phenotype and validate the quantitative algorithms for optimal classification power. [ABSTRACT FROM AUTHOR]

Purpose: To report the clinical features of pelvic fracture urethral injury (PFUI) and assess the real effect of factors that are believed to have adverse effects on delayed urethroplasty. Methods: An observational descriptive study in a single urological center examined 376 male patients diagnosed with PFUI who underwent open urethroplasty from 2009 to 2013. Analyzed factors included patient age at the time of injury, etiology of PFUI, type of emergency treatment, concomitant injuries, length and position of stricture, type of urethroplasty and the outcome of surgery. Univariate and multivariate logistic regression analyses were applied, together with analytical statistic methods such as t test and Chi-square test. Results: The overall success rate of delayed urethroplasty was 80.6 %. Early realignment was associated with reduced stricture length and had beneficial effect on delayed surgery. Concomitant rectum rupture, strictures longer than 1.6 cm and strictures closer than 3 cm to the bladder neck were indicators of poor outcome. Age, type of injury, urethral fistula and bladder rupture were not significant predicators of surgery outcome. Failed direct vision internal urethrotomy and urethroplasty had no significant influence on salvage operation. Conclusions: The outcome of posterior urethroplasty is affected by multiple factors. Early realignment has beneficial effect; while the length and position of stricture and its distance to bladder neck plays the key role, rectum rupture at the time of injury is also an indicator of poor outcome. The effect of other factors seems insignificant. [ABSTRACT FROM AUTHOR]

The ATP-gated P2X7 receptor is highly expressed in microglia and has been involved in diverse brain diseases. P2X7 effects were also described in neurons and astrocytes but its localisation and function in these cell types has been challenging to demonstrate in situ. BAC transgenic mouse lines have greatly advanced neuroscience research and two BAC-transgenic P2X7 reporter mouse models exist in which either a soluble EGFP (sEGFP) or an EGFP-tagged P2X7 receptor (P2X7-EGFP) is expressed under the control of a BAC-derived P2rx7 promoter. Here we evaluate both mouse models and find striking differences in both P2X expression levels and EGFP reporter expression patterns. Most remarkably, the sEGFP model overexpresses a P2X4 passenger gene and sEGFP shows clear neuronal localisation but appears to be absent in microglia. Preliminary functional analysis in a status epilepticus model suggests functional consequences of the observed P2X receptor overexpression. In summary, an aberrant EGFP reporter pattern and possible effects of P2X4 and/or P2X7 protein overexpression need to be considered when working with this model. We further discuss reasons for the observed differences and possible caveats in BAC transgenic approaches. [ABSTRACT FROM AUTHOR]