Parametric optimization and heat transfer analysis of a dual loop ORC (organic Rankine cycle) system for CNG engine waste heat recovery

In this study, a dual loop ORC (organic Rankine cycle) system is adopted to recover exhaust energy, waste heat from the coolant system, and intercooler heat rejection of a six-cylinder CNG (compressed natural gas) engine. The thermodynamic, heat transfer, and optimization models for the dual loop ORC system are established. On the basis of the waste heat characteristics of the CNG engine over the whole operating range, a GA (genetic algorithm) is used to solve the Pareto solution for the thermodynamic and heat transfer performances to maximize net power output and minimize heat transfer area. Combined with optimization results, the optimal parameter regions of the dual loop ORC system are determined under various operating conditions. Then, the variation in the heat transfer area with the operating conditions of the CNG engine is analyzed. The results show that the optimal evaporation pressure and superheat degree of the HT (high temperature) cycle are mainly influenced by the operating conditions of the CNG engine. The optimal evaporation pressure and superheat degree of the HT cycle over the whole operating range are within 2.5–2.9 MPa and 0.43–12.35 K, respectively. The optimal condensation temperature of the HT cycle, evaporation and condensation temperatures of the LT (low temperature) cycle, and exhaust temperature at the outlet of evaporator 1 are kept nearly constant under various operating conditions of the CNG engine. The thermal efficiency of the dual loop ORC system is within the range of 8.79%–10.17%. The dual loop ORC system achieves the maximum net power output of 23.62 kW under the engine rated condition. In addition, the operating conditions of the CNG engine and the operating parameters of the dual loop ORC system significantly influence the heat transfer areas for each heat exchanger

Unilateral versus bilateral percutaneous balloon kyphoplasty for osteoporotic vertebral compression fractures: A systematic review of overlapping meta-analyses

Background:Unilateral and bilateral percutaneous balloon kyphoplasty (PKP) are 2 main approaches for the treatment of patients with osteoporotic vertebral compression fractures (OVCFs). Numerous published systematic reviews and meta-analyses evaluating the effectiveness of 2 approaches remain inconclusive. In order to propose a significant principle to make decisions for comparing clinical safety and efficacy of unilateral versus bilateral PKP for treating OVCFs patients based on the currently best available evidence, a systematic review of overlapping meta-analysis was conducted.Methods:Three electronic databases, Pubmed/Medline, Embase2 and the Cochrance Library, were searched systematically to retrieve and identify all eligible systematic reviews and meta-analyses comparing unilateral and bilateral PKP for the treatment of patients with OVCFs. Only systematic reviews or meta-analyses with an exclusively pooled analysis of randomized controlled trials (RCTs) met the minimum eligibility criteria in this investigation. The Oxford Levels of Evidence, Jadad algorithm and Assessment of Multiple Systematic Reviews (AMSTAR) instrument were adopted for evaluation of the methodological quality for each included literature to select currently best available evidence.Results:Screening determined that out of 2159, 9 meta-analyses with level II or III of evidence met the inclusion criteria in the systematic review of overlapping meta-analyses. The multiple systematic reviews scores ranged from 8 to 9 with a mean of 8.55 (median 8.5). According to the search process and selection strategies of the Jadad algorithm, a meta-analysis by Feng et al with the best available evidence (12 RCTs and an AMSTAR score of 9) demonstrated that unilateral and bilateral PKP are both nice choices for the treatment of patients with OVCFs, and no significant differences were revealed in clinical scores, radiological outcomes, and quality of life with long-term follow-up. However, compared with bilateral PKP, unilateral PKP produced a shorter surgery time, smaller dosage of cement, lower risk of cement leakage, and relieved a higher degree of intractable pain at short-term follow-up after surgery.Conclusion:Unilateral percutaneous balloon kyphoplasty is more advantageous and superior to bilateral percutaneous kyphoplasty, and should be considered an effective option for the treatment of patients with osteoporotic vertebral compression fractures

Effectiveness of 3-dimensional shoulder ultrasound in the diagnosis of rotator cuff tears: A meta-analysis

Background: Numerous quantitatively based studies measuring the accuracy of 3D shoulder ultrasound (US) for the diagnosis of rotator cuff tears remain inconclusive. In order to determine how effective 3D shoulder US is for detecting rotator cuff tears, a meta-analysis was performed systematically. Methods: Six electronic databases, PubMed/Medline, Embase, Cochrane Library, CNKI, VIP data, and Wanfang data, were utilized to retrieve articles praising the diagnostic value of 3D shoulder US for use in detecting rotator cuff tears. After screening and diluting out the articles that met inclusion criteria to be used for statistical analysis, the pooled evaluation indexes including sensitivity, specificity, and diagnostic odds ratio (DOR) as well as the summary receiver operating characteristic curve (SROC) were calculated utilizing Meta-Disc v.1.4. Results: Screening determined that out of 4220, 7 studies involving a total of 282 patients were deemed viable for inclusion in the meta-analysis. The results of the analysis showed that the sensitivity and specificity were at 94% and 83%, respectively, with a DOR of 60.06, Q* index of 0.9058 and the area under SROC of 0.9609. Additionally, a satisfactory accuracy of 3D shoulder US was observed in detecting full-and partial-thickness rotator cuff tears. Conclusion: This meta-analysis suggests that 3D shoulder US is very effective and highly accurate to detect full-thickness rotator cuff tears, but may lack accuracy in the diagnosis of partial tears

Comparison of PET/CT and MRI in the Diagnosis of Bone Metastasis in Prostate Cancer Patients: A Network Analysis of Diagnostic Studies

Background: Accurate diagnosis of bone metastasis status of prostate cancer (PCa) is becoming increasingly more important in guiding local and systemic treatment. Positron emission tomography/computed tomography (PET/CT) and magnetic resonance imaging (MRI) have increasingly been utilized globally to assess the bone metastases in PCa. Our meta-analysis was a high-volume series in which the utility of PET/CT with different radioligands was compared to MRI with different parameters in this setting. Materials and Methods: Three databases, including Medline, Embase, and Cochrane Library, were searched to retrieve original trials from their inception to August 31, 2019 according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement. The methodological quality of the included studies was assessed by two independent investigators utilizing Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2). A Bayesian network meta-analysis was performed using an arm-based model. Absolute sensitivity and specificity, relative sensitivity and specificity, diagnostic odds ratio (DOR), and superiority index, and their associated 95% confidence intervals (CI) were used to assess the diagnostic value. Results: Forty-five studies with 2,843 patients and 4,263 lesions were identified. Network meta-analysis reveals that 68Ga-labeled prostate membrane antigen (68Ga-PSMA) PET/CT has the highest superiority index (7.30) with the sensitivity of 0.91 and specificity of 0.99, followed by 18F-NaF, 11C-choline, 18F-choline, 18F-fludeoxyglucose (FDG), and 18F-fluciclovine PET/CT. The use of high magnetic field strength, multisequence, diffusion-weighted imaging (DWI), and more imaging planes will increase the diagnostic value of MRI for the detection of bone metastasis in prostate cancer patients. Where available, 3.0-T high-quality MRI approaches 68Ga-PSMA PET/CT was performed in the detection of bone metastasis on patient-based level (sensitivity, 0.94 vs. 0.91; specificity, 0.94 vs. 0.96; superiority index, 4.43 vs. 4.56). Conclusions: 68Ga-PSMA PET/CT is recommended for the diagnosis of bone metastasis in prostate cancer patients. Where available, 3.0-T high-quality MRI approaches 68Ga-PSMA PET/CT should be performed in the detection of bone metastasis

Effectiveness of 18F-FDG PET/CT in the diagnosis, staging and recurrence monitoring of Ewing sarcoma family of tumors: A meta-analysis of 23 studies

Background: To investigate the value of positron emission tomography (PET) and PET/computed tomography (CT) using fluorine-18-fluorodeoxyglucose (F-18-FDG) in the diagnosis, staging, restaging and recurrence monitoring of Ewing sarcoma family of tumors (ESFTs), a meta-analysis was performed through systematically searching PubMed, Embase, and Cochrane Central library to retrieve articles. Methods: After screening and diluting out the articles that met inclusion criteria to be used for statistical analysis the pooled evaluation indexes including sensitivity, specificity, and diagnostic odd ratio (DOR) as well as the summary receiver operating characteristic curve (SROC) were calculated involving diagnostic data (true positive, false positive, false negative, and true negative) extracted from original studies. Results: Screening determined that out of 2007, 23 studies involving a total of 524 patients were deemed viable for inclusion in the meta-analysis. The results of the analysis showed that the sensitivity and specificity were at 86% and 80%, respectively. Additionally, a satisfactory accuracy of F-18-FDG PET and PET/CT was observed in detecting ESFT recurrence, lung metastasis, and osseous metastasis. Conclusion: This meta-analysis suggests that F-18-FDG PET and PET/CT with an extremely high accuracy could be considered a valuable method for detecting distant metastasis and post-operational recurrence of ESFT, which might have a profound impact on the development of treatment protocols for ESFT

The development of an ingestible biosensor for the characterization of gut metabolites related to major depressive disorder: hypothesis and theory

The diagnostic process for psychiatric conditions is guided by the Diagnostic and Statistical Manual of Mental Disorders (DSM) in North America. Revisions of the DSM over the years have led to lowered diagnostic thresholds across the board, incurring increased rates of both misdiagnosis and over-diagnosis. Coupled with stigma, this ambiguity and lack of consistency exacerbates the challenges that clinicians and scientists face in the clinical assessment and research of mood disorders such as Major Depressive Disorder (MDD). While current efforts to characterize MDD have largely focused on qualitative approaches, the broad variations in physiological traits, such as those found in the gut, suggest the immense potential of using biomarkers to provide a quantitative and objective assessment. Here, we propose the development of a probiotic Escherichia coli (E. coli) multi-input ingestible biosensor for the characterization of key gut metabolites implicated in MDD. DNA writing with CRISPR based editors allows for the molecular recording of signals while riboflavin detection acts as a means to establish temporal and spatial specificity for the large intestine. We test the feasibility of this approach through kinetic modeling of the system which demonstrates targeted sensing and robust recording of metabolites within the large intestine in a time- and dose- dependent manner. Additionally, a post-hoc normalization model successfully controlled for confounding factors such as individual variation in riboflavin concentrations, producing a linear relationship between actual and predicted metabolite concentrations. We also highlight indole, butyrate, tetrahydrofolate, hydrogen peroxide, and tetrathionate as key gut metabolites that have the potential to direct our proposed biosensor specifically for MDD. Ultimately, our proposed biosensor has the potential to allow for a greater understanding of disease pathophysiology, assessment, and treatment response for many mood disorders

Powder Technol.

Gas-solid interaction does exist both outside and inside particle clusters in gas-solid two-phase flow, but the penetrating flow through clusters was generally neglected in most mathematical models of clusters. As regards to what extent the penetrating flow exists in gas-solid flow and how the penetrating flow affects gas-solid interaction, there are still no universally accepted viewpoint and quantitative characterization until now. By utilizing both CFD (Computational Fluid Dynamics) simulations and PIV (Particle Image Velocimetry) measurements, this article quantitatively investigates the gas and dilute gas-solid penetrating flows through different pseudo two-dimensional clusters in a two-dimensional gas-solid fluidized bed. The solid penetrating flow through clusters seldom occurs, but the gas penetrating flow increases exponentially with increasing internal voidage of clusters, which is however affected little by superficial gas velocity under the tested operating conditions. These results imply that the effect of the gas penetrating flow through clusters must be taken into consideration when investigating particle clustering behavior in gas-solid two-phase flow. (C) 2012 Elsevier B.V. All rights reserved.Gas-solid interaction does exist both outside and inside particle clusters in gas-solid two-phase flow, but the penetrating flow through clusters was generally neglected in most mathematical models of clusters. As regards to what extent the penetrating flow exists in gas-solid flow and how the penetrating flow affects gas-solid interaction, there are still no universally accepted viewpoint and quantitative characterization until now. By utilizing both CFD (Computational Fluid Dynamics) simulations and PIV (Particle Image Velocimetry) measurements, this article quantitatively investigates the gas and dilute gas-solid penetrating flows through different pseudo two-dimensional clusters in a two-dimensional gas-solid fluidized bed. The solid penetrating flow through clusters seldom occurs, but the gas penetrating flow increases exponentially with increasing internal voidage of clusters, which is however affected little by superficial gas velocity under the tested operating conditions. These results imply that the effect of the gas penetrating flow through clusters must be taken into consideration when investigating particle clustering behavior in gas-solid two-phase flow. (C) 2012 Elsevier B.V. All rights reserved

Effectiveness of 18F-FDG PET/CT in the diagnosis and staging of osteosarcoma: a meta-analysis of 26 studies

Abstract Background Multiple trials have attempted to assess the diagnostic value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in osteosarcoma with results remaining inconclusive. This study aims to investigate the effectiveness of 18F-FDG PET and PET/CT in the diagnosis, staging, recurrence and metastasis formation observations of osteosarcoma through systematic review followed by meta-analysis. Methods Three electronic databases, Medline/PubMed, Embase and the Cochrane Library were utilized in this study. Eligible studies that assessed the performance of 18F-FDG PET/CT for the diagnosis, staging, restaging and recurrence monitoring of osteosarcoma were retrieved utilizing specific search criteria. After screening and diluting out the non-conforming articles, all relevant articles and their data were identified and extracted to calculate the summary metrics involving sensitivity, specificity, diagnostic odd ratio (DOR), and area under the curve (AUC) to determine the effectiveness of 18F-FDG PET in diagnosing osteosarcoma clinically. Results Out of 1976 articles searched, twenty-six studies were identified that were viable. All data from these articles, utilized in the quantitative analyses, showed after meta-analysis that when utilizing 18F-FDG PET or PET/CT it was better with a success rate of 90–100% for detecting primary lesions and distant metastases of patients with osteosarcoma. Similar results were also obtained for detecting lung and bone metastases in a subgroup analysis. Conclusions As such the investigation demonstrated that 18F-FDG PET and PET/CT are very accurate for the diagnosis, staging and recurrence monitoring of osteosarcoma. 18F-FDG-avid lesions should be further examined in osteosarcoma, especially for suspicious lung lesions

Passenger Demand-Oriented High-Speed Train Stop Planning with Service-Node Features Analysis

As a critical foundation for train traffic management, a train stop plan is associated with several other plans in high-speed railway train operation strategies. The current approach to train stop planning in China is based primarily on passenger demand volume information and the preset high-speed railway station level. With the goal of efficiently optimising the stop plan, this study proposes a novel method that uses machine learning techniques without a predetermined hypothesis and a complex solution algorithm. Clustering techniques are applied to assess the features of the service nodes (e.g., the station level). A modified Markov decision process (MDP) is conducted to express the entire stop plan optimisation process considering several constraints (service frequency at stations and number of train stops). A restrained MDP-based stop plan model is formulated, and a numerical experiment is conducted to demonstrate the performance of the proposed approach with real-world train operation data collected from the Beijing-Shanghai high-speed railway