Inspection is a crucial activity for an engineered system as its results can reduce the uncertainty of identifying the true states of the system and its components, so as to facilitate subsequent ...proactive maintenance. The preliminary work to conduct an inspection activity is to evaluate its effectiveness. In many real-world scenarios, engineered systems oftentimes possess both multistate and hierarchical characteristics, and inspection can be performed across multiple physical levels of a system. We, therefore, need a measure to assess the effectiveness of a multilevel inspection activity of multistate systems. Inspired by the concept of importance measure, in this article, we define a new measure, namely, inspection importance measure (InsIM), to assess the contribution of a multilevel inspection strategy to the efficiency improvement of the subsequent preventive maintenance from a value of information perspective. The proposed measure evaluates the increased efficiency of preventive maintenance after conducting multilevel inspection activities. The procedure of the proposed InsIM contains four steps: 1) calculating the efficiency of the optimal maintenance policy identified without inspections, 2) updating the system's state distribution by multilevel inspection activities, 3) calculating the efficiency of the optimal maintenance policy identified with inspections, and 4) evaluating the expected improvement of maintenance policy. A five-component system and a real-world programmable logic controller control system are exemplified to demonstrate the accuracy and effectiveness of the proposed method. The results indicate that the InsIM can significantly enhance the efficiency of the subsequent proactive maintenance decision.
Nghiên cứu này đánh giá sự phát triển và vai trò cỏ voi (Pennisetum purpureum) trồng trong đất ngập nước nhân tạo dòng chảy ngầm xử lý nước thải sinh hoạt. Nghiên cứu được thực hiện với mô hình phòng ...thí nghiệm trồng cỏ voi trên nền lọc xỉ than tổ ong. Mô hình đối chứng không trồng thực vật cũng được tiến hành song song. Nước thải sinh hoạt được cấp vào hệ thống với tải nạp là 35 L/m2/ngày. Kết quả nghiên cứu cho thấy các chỉ tiêu lý hóa trong nước thải như TSS, BOD5, N-NH4+, N-NO3-, P-PO43- sau xử lý đạt QCVN 14:2008/BTNMT (cột A). Cỏ voi phát triển tốt và góp phần nâng cao hiệu suất loại bỏ chất ô nhiễm trong nước thải, đặc biệt là N-NO3- và P-PO43-. Tuy nhiên, tổng coliform trong nước thải sau xử lý cao hơn quy chuẩn mặc dù hiệu suất xử lý của 2 mô hình đạt 95,1% và 98,5%. Nghiên cứu chỉ ra rằng cỏ voi phát triển tốt và có thể chọn để trồng trong đất ngập nước nhân tạo dòng chảy ngầm để loại bỏ chất ô nhiễm trong nước thải sinh hoạt.
•We found 258 missense mutations in spike glycoprotein of Iranian SARS-CoV-2.•Most of these mutations could potentially result in escape from neutralizing antibodies.•We found circulation of four ...current VOCs – Alpha, Beta, Gamma and Delta - indifferent regions in Iran.
Since late 2019, when SARS-CoV-2 was reported at Wuhan, several sequence analyses have been performed and SARS-CoV-2 genome sequences have been submitted in various databases. Moreover, the impact of these variants on infectivity and response to neutralizing antibodies has been assessed. In the present study, we retrieved a total number of 176 complete and high-quality S glycoprotein sequences of Iranian SARS-COV-2 in public database of the GISAID and GenBank from April 2020 up to May 2021. Then, we identified the number of variables, singleton and parsimony informative sites at both gene and protein levels and discussed the possible functional consequences of important mutations on the infectivity and response to neutralizing antibodies. Phylogenetic tree was constructed to represent the relationship between Iranian SARS-COV2 and variants of concern (VOC), variants of interest (VOI) and reference sequence. We found that the four current VOCs – Alpha, Beta, Gamma and Delta – are circulated in different regions in Iran. The Delta variant is notably more transmissible than other variants, and is expected to become a dominant variant. However, some of the Delta variants in Iran carry an additional mutation, namely E1202Q in the HR2 subdomain that might confer an advantage to viral/cell membrane fusion process. We also observed some more common mutations such as an N-terminal domain (NTD) deletion at position I210 and P863H in fusion peptide-heptad repeat 1 span region in Iranian SARS-COV-2. The reported mutations in the current project have practical significance in prediction of disease spread as well as design of vaccines and drugs.
The T2-FLAIR mismatch sign on MR imaging is a highly specific imaging biomarker of isocitrate dehydrogenase (
)-mutant astrocytomas, which lack 1p/19q codeletion. However, most studies using the ...T2-FLAIR mismatch sign have used visual assessment. This study quantified the degree of T2-FLAIR mismatch using digital subtraction of fluid-nulled T2-weighted FLAIR images from non-fluid-nulled T2-weighted images in human nonenhancing diffuse gliomas and then used this information to assess improvements in diagnostic performance and investigate subregion characteristics within these lesions.
Two cohorts of treatment-naïve, nonenhancing gliomas with known
and 1p/19q status were studied (
= 71 from The Cancer Imaging Archive (TCIA) and
= 34 in the institutional cohort). 3D volumes of interest corresponding to the tumor were segmented, and digital subtraction maps of T2-weighted MR imaging minus T2-weighted FLAIR MR imaging were used to partition each volume of interest into a T2-FLAIR mismatched subregion (T2-FLAIR mismatch, corresponding to voxels with positive values on the subtraction maps) and nonmismatched subregion (T2-FLAIR nonmismatch corresponding to voxels with negative values on the subtraction maps). Tumor subregion volumes, percentage of T2-FLAIR mismatch volume, and T2-FLAIR nonmismatch subregion thickness were calculated, and 2 radiologists assessed the T2-FLAIR mismatch sign with and without the aid of T2-FLAIR subtraction maps.
Thresholds of ≥42% T2-FLAIR mismatch volume classified
-mutant astrocytoma with a specificity/sensitivity of 100%/19.6% (TCIA) and 100%/31.6% (institutional); ≥25% T2-FLAIR mismatch volume showed 92.0%/32.6% and 100%/63.2% specificity/sensitivity, and ≥15% T2-FLAIR mismatch volume showed 88.0%/39.1% and 93.3%/79.0% specificity/sensitivity. In
-mutant astrocytomas with ≥15% T2-FLAIR mismatch volume, T2-FLAIR nonmismatch subregion thickness was negatively correlated with the percentage T2-FLAIR mismatch volume (
< .0001) across both cohorts. The percentage T2-FLAIR mismatch volume was higher in grades 3-4 compared with grade 2
-mutant astrocytomas (
< .05), and ≥15% T2-FLAIR mismatch volume
mutant astrocytomas were significantly larger than <15% T2-FLAIR mismatch volume
-mutant astrocytoma (
< .05) across both cohorts. When evaluated by 2 radiologists, the additional use of T2-FLAIR subtraction maps did not show a significant difference in interreader agreement, sensitivity, or specificity compared with a separate evaluation of T2-FLAIR and T2-weighted MR imaging alone.
T2-FLAIR digital subtraction maps may be a useful, automated tool to obtain objective segmentations of tumor subregions based on quantitative thresholds for classifying
-mutant astrocytomas using the percentage T2 FLAIR mismatch volume with 100% specificity and exploring T2-FLAIR mismatch/T2-FLAIR nonmismatch subregion characteristics. Conversely, the addition of T2-FLAIR subtraction maps did not enhance the sensitivity or specificity of the visual T2-FLAIR mismatch sign assessment by experienced radiologists.
The current Internet of Underwater Things (IoUT) for marine observations and emergency responses suffers from two critical issues: 1) energy efficient and 2) timely data collection. Autonomous ...underwater vehicles (AUVs), serving as tools for collecting and forwarding distributed data, can deal with the unbalanced power consumption in a traditional multihop underwater communication network. However, the low speed of the AUV has not been able to guarantee the timeliness of delay-sensitive data. In this article, we introduce a hybrid data collection scheme (HDCS), taking both real-time data collection and energy efficiency (EE) issues into consideration. All sensor nodes (SNs) are first clustered based on their locations in the network. We develop an analytic expression to describe the attenuation of Value of Information (VoI), involving the relationship between the importance degree and timeliness; initial VoI could be measured by historical data. The emergency can be recognized by the presented criterion, and the transmission mode of cluster heads (CHs) in the same layer is judged by CHs themselves according to VoI. The selected CHs shall transmit the urgent data via multihop routing to avoid over attenuation of VoI. The normal data are collected by AUVs visiting all remaining CHs, and the shortest trajectory is achieved by addressing a variation of the classic traveling salesman problem (TSP). Our simulation experiments show that this mechanism can effectively increase long-term VoI while significantly improving EE.
•Nation-wide genomic analysis could detect seven different phases of SARS-CoV-2 pandemic in India.•Variant of concern and variant of interest were dominated only post-first wave in India.•More than ...0.5 million mutational events could be detected across 20,086 high quality genomes.•Four major mutational events i.e., spike (D614G), NSP 12b (P314L), NSP3 F106F and 5′ UTR 241 occurring in more than 19,000 genomes.
COVID-19 has posed unforeseen circumstances and throttled major economies worldwide. India has witnessed two waves affecting around 31 million people representing 16% of the cases globally. To date, the epidemic waves have not been comprehensively investigated to understand pandemic progress in India.
Here, we aim for pan Indian cross-sectional evolutionary analysis since inception of SARS-CoV-2.
High quality genomes, along with their collection date till 26th July 2021, were downloaded. Whole genome-based phylogeny was obtained. Further, the mutational analysis was performed using SARS-CoV-2 first reported from Wuhan (NC_045512.2) as reference.
Based on reported cases and mutation rates, we could divide the Indian epidemic into seven phases. The average mutation rate for the pre-first wave was <11, which elevated to 17 in the first wave and doubled in the second wave (∼34). In accordance with mutation rate, VOCs and VOIs started appearing in the first wave (1.5%), which dominated the second (∼96%) and post-second wave (100%). Nation-wide mutational analysis depicted >0.5 million mutation events with four major mutations in >19,300 genomes, including two mutations in coding (spike (D614G), and NSP 12b (P314L) of rdrp), one silent mutation (NSP3 F106F) and one extragenic mutation (5′ UTR 241).
Whole genome-based phylogeny could demarcate post-first wave isolates from previous ones by point of diversification leading to incidences of VOCs and VOIs in India. Such analysis is crucial in the timely management of pandemic.
The severe acute respiratory syndrome coronavirus (SARS-CoV)-2 responsible for the global COVID-19 pandemic has caused almost 760 million confirmed cases and 7 million deaths worldwide, as of ...end-February 2023. Since the beginning of the first COVID-19 case, several virus variants have emerged: Alpha (B1.1.7), Beta (B135.1), Gamma (P.1), Delta (B.1.617.2) and then Omicron (B.1.1.529) and its sublineages. All variants have diversified in transmissibility, virulence, and pathogenicity. All the newly emerging SARS-CoV-2 variants appear to contain some similar mutations associated with greater "evasiveness" of the virus to immune defences. From early 2022 onward, several Omicron subvariants named BA.1, BA.2, BA.3, BA.4, and BA.5, with comparable mutation forms, have followed. After the wave of contagions caused by Omicron BA.5, a new Indian variant named Centaurus BA.2.75 and its new subvariant BA.2.75.2, a second-generation evolution of the Omicron variant BA.2, have recently been identified. From early evidence, it appears that this new variant has higher affinity for the cell entry receptor ACE-2, making it potentially able to spread very fast. According to the latest studies, the BA.2.75.2 variant may be able to evade more antibodies in the bloodstream generated by vaccination or previous infection, and it may be more resistant to antiviral and monoclonal antibody drug treatments. In this manuscript, the authors highlight and describe the latest evidences and critical issues have emerged on the new SARS-CoV-2 variants.
This article proposes a new passive islanding detection technique for inverter-based distributed generation (DG) in microgrids based on local synchrophasor measurements. The proposed method utilizes ...the voltage and current phasors measured at the DG connection point (point of connection, PoC). In this paper, the rate of change of voltages and the ratio of the voltage and current magnitudes (VoI index) at the PoC are monitored using micro-phasor measurement units. The developed local measurements based decentralized islanding detection technique is based on the VoI index in order to detect any kind of utility grid frequency fluctuations or oscillations and distinguishing them from islanding condition. The simulation studies confirm that the proposed scheme is accurate, robust, fast, and simple to implement for inverter-based DGs.
Abstract This study investigated the effects of dual delivery of vascular endothelial growth factor (VEGF) and bone morphogenetic protein-2 (BMP-2) for bone regeneration in a rat cranial critical ...size defect. Four groups of scaffolds were generated with VEGF (12 μg), BMP-2 (2 μg), both VEGF (12 μg) and BMP-2 (2 μg), or no growth factor released from gelatin microparticles incorporated within the scaffold pores. These scaffolds were implanted within an 8 mm rat cranial critical size defect ( n = 8–9 for each group). At 4 and 12 weeks, implants were retrieved and evaluated by microcomputed tomography (microCT) and histological scoring analysis. Additionally, 4 week animals were perfused with a radiopaque material to visualize and quantify blood vessel formation. Histological analysis revealed that for all groups at 4 weeks, a majority of the porous scaffold volume was filled with vascularized fibrous tissue; however, bone formation appeared most abundant in the dual release group at this time. At 12 weeks, both dual release and BMP-2 groups showed large amounts of bone formation within the scaffold pores and along the outer surfaces of the scaffold; osteoid secretion and mineralization were apparent, and new bone was often in close or direct contact with the scaffold interface. MicroCT results showed no significant difference among groups for blood vessel formation at 4 weeks (< 4% blood vessel volume); however, the dual release group showed significantly higher bone formation (16.1 ± 9.2% bone volume) than other groups at this time. At 12 weeks, dual release and BMP-2 groups exhibited significantly higher bone formation (39.7 ± 14.1% and 37.4 ± 18.8% bone volume, respectively) than either the VEGF group or blank scaffolds (6.3 ± 4.8% and 7.8 ± 7.1% bone volume, respectively). This work indicates a synergistic effect of the dual delivery of VEGF and BMP-2 on bone formation at 4 weeks and suggests an interplay between these growth factors for early bone regeneration. For the doses investigated, the results show that the addition of VEGF does not affect the amount of bone formation achieved by BMP-2 at 12 weeks; however, they also indicate that delivery of both growth factors may enhance bone bridging and union of the critical size defect compared to delivery of BMP-2 alone.
The Internet of Underwater Things (IoUT) shows great potential in realizing the smart ocean. Underwater acoustic sensor networks (UWASNs) are the main existing form of IoUT but face with reliable ...data transmission problems. To tackle this issue, this article considers using the autonomous underwater vehicle (AUV) as a mobile collector to construct a reliable hierarchical information collection system while the Value of Information (VoI) is used as a main metric to measure the Quality of Information (QoI). We first establish a realistic model for characterizing the behaviors of AUV and sensor nodes as well as the challenging environments. Then, to construct a hierarchical architecture, we design a sink node (SN) selection scheme by jointly considering VoI conservation and energy load balancing. After that, we focus on AUV path planning with the objective of maximizing the VoI of the total network. We formulate the problem as a combinatorial optimization problem and provide an integer linear programming (ILP) model for this problem. An optimal algorithm based on the branch-and-bound (BB) method is proposed for seeking for the optimal solution, in which the lower bound and upper bound calculation strategies are specifically designed. Two near-optimal heuristic algorithms based on the concepts of the ant colony algorithm (ACA) and the genetic algorithm (GA) are also provided for further reducing the computation complexity. Finally, simulations validate the effectiveness of the proposed algorithms.
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