bluuebunny/crossref_metadata_2025 huggingface dataset:
Ratio between Right Ventricular Longitudinal Strain and Pulmonary Arterial Systolic Pressure: Novel Prognostic Parameter in Patients Undergoing Cardiac Resynchronization Therapy
Authors: Deaconu Silvia , Deaconu Alexandru , Scarlatescu Alina , Petre Ioana , Onciul Sebastian , Vijiiac Aura , Zamfir Diana , Marascu Gabriela , Iorgulescu Corneliu , Radu Andrei Dan , Bogdan Stefan , Vatasescu Radu
Published: June 2021

Background: We aimed to evaluate whether right ventricle (RV) longitudinal strain indexed to pulmonary arterial systolic pressure (PASP) has prognostic significance in patients undergoing cardiac resynchronization therapy (CRT). Methods: Patients undergoing CRT were prospectively included. The primary endpoint was adverse cardiovascular events (death and HF-related hospitalizations). RV global longitudinal strain (RVGLS) and RV free wall strain (RVfwS) were measured by speckle tracking and indexed to echocardiographic estimated PASP. Results: A total of 54 patients (64.0 ± 13.8 years; 58% male) were included. After 33 ± 12.9 months, the primary endpoint occurred in 18 patients. Baseline RVGLS/PASP and RVfwS/PASP showed good discriminative ability for response to CRT (AUC = 0.88, 95% CI (0.74–1) and AUC = 0.87, 95% CI (0.77–1)). RVGLS/PASP and RVfwS/PASP were significantly associated with high risk of events at univariate analysis (HR 0.039, 95% CI (0.001–0.8) p < 0.05, respectively HR = 0.049, 95% CI (0.0033–0.72), p < 0.05). Upon multivariate Cox regression analysis, RVGLS/PASP and RVfwS/PASP remained associated with high risk of events (HR 0.018, 95% CI (0.0005–0.64), p = 0.02 and HR 0.015, 95% CI (0.0004–0.524), p = 0.01) after correction for gender, etiology, QRS duration and morphology. Conclusions: Indexing RV longitudinal strain (global and free wall) by PASP provides a parameter, which independently identifies patients with high risk of cardiovascular events and predicts non-response to CRT.
Reference Intervals of Thyroid Function Tests Assessed by Immunoassay and Mass Spectrometry in Healthy Pregnant Women Living in Catalonia
Authors: Hernández José María , Soldevila Berta , Velasco Inés , Moreno-Flores Fernando , Ferrer Laura , Pérez-Montes de Oca Alejandra , Santillán Cecilia , Muñoz Carla , Ballesta Sílvia , Canal Cristina , Puig-Domingo Manel , Granada María Luisa
Published: June 2021

Background: Recent guidelines recommend establishing a local reference interval (RI) for thyroid function. We aimed to establish trimester-specific RIs for thyrotropin (TSH) and free thyroxine (FT4) in a cohort of healthy pregnant women in Catalonia (Spain). Methods: A prospective observational study was conducted with 332 healthy pregnant women, from the first trimester (1T) to delivery. TSH was measured using an Architect® immunoassay (Abbott) and FT4 by two immunoassays, Architect® (Abbott) and Cobas® (Roche), in the three trimesters. FT4 was also measured by liquid chromatography mass spectrometry (LC/MS/MS) in the 1T. Results: TSH (µUI/mL) increased throughout pregnancy (1T: 0.03–3.78; 2T: 0.51–3.53; 3T: 0.50–4.32; p < 0.0001) and FT4 (pmol/L) progressively decreased (Architect® 1T: 10.42–15.96; 2T: 8.37–12.74; 3T: 8.24–12.49; p < 0.0001; and Cobas®: 1T: 11.46–19.05; 2T: 9.65–14.67; 3T: 8.88–14.54; p < 0.0067). The FT4 RI during 1T determined LC/MS/MS was 8.75–18.27. Despite the 1T FT4 results measured by LC/MS/MS and with the two immunoassays being significantly correlated, the results obtained by the three methods were found to be non-interchangeable. Conclusions: We established trimester-specific RIs for TSH and for FT4 with immunoassays in our population. We also validated the 1T FT4 using LC/MS/MS to confirm the results of FT4 lower than the 2.5th percentile or higher than the 97.5th percentile.
Post-COVID-19 Pulmonary Fibrosis: Novel Sequelae of the Current Pandemic
Authors: Ambardar Shiva Rattan , Hightower Stephanie L. , Huprikar Nikhil A. , Chung Kevin K. , Singhal Anju , Collen Jacob F.
Published: June 2021

Since the initial identification of the novel coronavirus SARS-CoV-2 in December 2019, the COVID-19 pandemic has become a leading cause of morbidity and mortality worldwide. As effective vaccines and treatments begin to emerge, it will become increasingly important to identify and proactively manage the long-term respiratory complications of severe disease. The patterns of imaging abnormalities coupled with data from prior coronavirus outbreaks suggest that patients with severe COVID-19 pneumonia are likely at an increased risk of progression to interstitial lung disease (ILD) and chronic pulmonary vascular disease. In this paper, we briefly review the definition, classification, and underlying pathophysiology of interstitial lung disease (ILD). We then review the current literature on the proposed mechanisms of lung injury in severe COVID-19 infection, and outline potential viral- and immune-mediated processes implicated in the development of post-COVID-19 pulmonary fibrosis (PCPF). Finally, we address patient-specific and iatrogenic risk factors that could lead to PCPF and discuss strategies for reducing risk of pulmonary complications/sequelae.
Small Drainage Volumes of Pleural Effusions Are Associated with Complications in Critically Ill Patients: A Retrospective Analysis
Authors: Treml Benedikt , Rajsic Sasa , Diwo Felix , Hell Tobias , Hochhold Christoph
Published: June 2021

Pleural effusions are a common finding in critically ill patients and small bore chest drains (SBCD) are proven to be efficient for pleural drainage. The data on the potential benefits and risks of drainage remains controversial. We aimed to determine the cut-off volume for complications, to investigate the impact of pleural drainage and drained volume on clinically relevant outcomes. Medical records of all critically ill patients undergoing insertion of SBCD were retrospectively examined. We screened 13,003 chest radiographs and included 396 SBCD cases in the final analysis. SBCD drained on average 900 mL, with less amount in patients with complications (p = 0.003). A drainage volume of 975 mL in 24 h represented the optimal threshold for complications. Pneumothorax was the most frequent complication (4.5%), followed by bleeding (0.8%). Female and lighter-weighted patients experienced a higher risk for any complication. We observed an improvement in the arterial partial pressure of oxygen and respiratory quotient (p < 0.001). We conclude that the small drainage volumes are associated with complications in critically ill patients—the more you drain, the safer the procedure gets. The use of SBCD is a safe and efficient procedure, further investigations regarding the higher rate of complications in female and lighter-weighted patients are desirable.
Marine Litter
Authors: Renzi Monia , Guerranti Cristiana
Published: June 2021

This short editorial aims to present the content of, summarize and draw conclusions from the six articles published in the Special Issue “Marine Litter” [...]
Use of Antiplatelet Agents Decreases the Positive Predictive Value of Fecal Immunochemical Tests for Colorectal Cancer but Does Not Affect Their Sensitivity
Authors: Jung Yoonsuk , Im Eui , Lee Jinhee , Lee Hyeah , Moon Changmo
Published: June 2021

Previous studies have evaluated the effects of antithrombotic agents on the performance of fecal immunochemical tests (FITs) for the detection of colorectal cancer (CRC), but the results were inconsistent and based on small sample sizes. We studied this topic using a large-scale population-based database. Using the Korean National Cancer Screening Program Database, we compared the performance of FITs for CRC detection between users and non-users of antiplatelet agents and warfarin. Non-users were matched according to age and sex. Among 5,426,469 eligible participants, 768,733 used antiplatelet agents (mono/dual/triple therapy, n = 701,683/63,211/3839), and 19,569 used warfarin, while 4,638,167 were non-users. Among antiplatelet agents, aspirin, clopidogrel, and cilostazol ranked first, second, and third, respectively, in terms of prescription rates. Users of antiplatelet agents (3.62% vs. 4.45%; relative risk (RR): 0.83; 95% confidence interval (CI): 0.78–0.88), aspirin (3.66% vs. 4.13%; RR: 0.90; 95% CI: 0.83–0.97), and clopidogrel (3.48% vs. 4.88%; RR: 0.72; 95% CI: 0.61–0.86) had lower positive predictive values (PPVs) for CRC detection than non-users. However, there were no significant differences in PPV between cilostazol vs. non-users and warfarin users vs. non-users. For PPV, the RR (users vs. non-users) for antiplatelet monotherapy was 0.86, while the RRs for dual and triple antiplatelet therapies (excluding cilostazol) were 0.67 and 0.22, respectively. For all antithrombotic agents, the sensitivity for CRC detection was not different between users and non-users. Use of antiplatelet agents, except cilostazol, may increase the false positives without improving the sensitivity of FITs for CRC detection.
Integrated Thinking and Reporting Process: Sensemaking of Internal Actors in the Case of Itaú Unibanco
Authors: Favato Kelli Juliane , Neumann Marguit , Sanches Simone Leticia Raimundini , Branco Manuel Castelo , Nogueira Daniel Ramos
Published: June 2021

This study aims to understand the meaning created by Itaú Unibanco’s internal actors in the Integrated Reporting (IR) processes. An interpretative approach based on Karl Weick’s sensemaking perspective is adopted. A case study methodology was adopted for undertaking the empirical work. The results show that IR identity in the institution is related to three issues: synergy processes between sectors; integration for the production of other reports; and development of an integrated thinking chain for the entire business. We present perceptions on benefits and difficulties in the process of preparing the integrated report. Although the practices and processes established did not change the characteristics of the bank, the perspective of the social actors seems to have changed from a sectoral view to a multidimensional view. In addition, the conclusions suggest that it is not difficult to understand that separating ‘thinking’ from ‘doing’, attributing to the individual the role of mere operationalization is tantamount to ignore the meaning attributed to the organization’s journey towards the creation of a process, namely the IR one. The study’s contribution lies in pointing out that the IR process is directly related to the integrated thinking process. This could be the most significant differential of IR as a form of corporate communication as it amounts to a new reporting framework that proposes integrating social, environmental, and governance disclosures (non-financial information) with financial disclosures in a single report.
Examining the Spatial Coordination between Metrorail Accessibility and Urban Spatial Form in the Context of Big Data
Authors: Liu Jingming , Hou Xianhui , Xia Chuyu , Kang Xiang , Zhou Yujun
Published: June 2021

Metrorail accessibility is an important indicator that influences urban spatial form. For this article, we created a 3SFCA method to analyze the Metrorail accessibility of Shanghai covering four levels: traffic analysis zones (TAZs), stations, metrorail network, and regions. The floor area ratio (FAR) was used to reflect the urban form, and spatial coordination model was introduced to examine the spatial balance between metrorail accessibility and urban forms. Results revealed that the spatial distribution of metrorail accessibility and urban form are characterized by a monocentric spatial structure, while the values of both variables decrease gradually from urban center to suburban regions, with the regional difference being significantly greater than the other three levels. The results also indicated that the development of metrorail stations has a time lag effect on the urban spatial form, and the catchment area of a metro station shows characteristics of gradually expanding and then shrinking from city center to suburban regions. Finally, the results showed that there is a strong coordination between accessibility and urban form around metro stations, but the coordinate degree varies by regions. Thus, we concluded that station density should be increased within the fourth ring, FAR should be increased between the second and third rings, and rail transit capacity in the urban center area should be increased.
Establishment of Crops under Minimal Soil Disturbance and Crop Residue Retention in Rice-Based Cropping System: Yield Advantage, Soil Health Improvement, and Economic Benefit
Authors: Salahin Nazmus , Jahiruddin Mohammad , Islam Mohammad Rafiqul , Alam Md. Khairul , Haque M. Enamul , Ahmed Sharif , Baazeem Alaa , Hadifa Adel , EL Sabagh Ayman , Bell Richard W.
Published: June 2021

Minimum soil disturbance and increased crop residue retention practices are promising options to enhance soil organic matter, nutrient concentration and crop yield. However, the potentials of the practices in improving soil properties, increasing crop yield and in ensuring economic return have not been tested in the monsoon rice (Oryza sativa L.)-lentil (Lens culinaris L.)/wheat (Triticum aestivum L.)-jute (Corchorus culinaris L.) cropping systems on seasonally flooded lowlands of the Eastern Gangetic Plain of South Asia. A field trial for consecutive three years was conducted in the Gangetic Plains of Bangladesh to evaluate the effects of zero tillage (ZT), strip-tillage (ST), bed planting (BP) and conventional tillage (CT) with two residue retention levels (RL—a low level similar to current farmers’ practice and RH—increased retention) on soil properties, yield and economic return. Between rice and jute crops, lentil was grown for the 1st and 2nd years and wheat for the 3rd year during the dry winter season. The ST and BP performed better than the CT and ZT in terms of yield of rice and lentil, whereas ST and ZT performed better than other practices in the case of jute. Higher residue retention (RH) increased crop yield for all the years. The highest rice equivalent yield (sum of 3 crop yields, expressed as rice yield) and the greatest benefit-cost ratio (BCR) were recorded with ST and RH. The increased yield in the ST was associated with reduced soil bulk density (BD), while ST with RH increased soil water (SW) and decreased penetration resistance (PR) of soil. Compared to CT, minimum soil disturbance of ZT and ST increased soil organic matter (SOM) stock by 24% and 23%, respectively; total nitrogen (TN) by 23.5% and 18.4%, respectively; extractable sulphur (S) by 21% and 18%, respectively; whereas Zinc (Zn) concentrations increased by 53% and 47%, respectively, in the upper 0–5 cm soil depth. Accumulation of extractable P, S and Zn in the 0–5 cm depth of soil followed the sequence as ZT > ST > BP > CT practice. The higher amount of residue retention significantly increased SOM, TN and extractable P, K, S and Zn concentrations at 0–5 cm and 5–10 cm soil depths. The 3-year study suggests that ST with RH is a potential crop management approach for the seasonally flooded rice-lentil/wheat-jute cropping systems to enhance soil nutrients status, crop yield and farm economy.
Spatiotemporal Change Analysis and Future Scenario of LULC Using the CA-ANN Approach: A Case Study of the Greater Bay Area, China
Authors: Abbas Zaheer , Yang Guang , Zhong Yuanjun , Zhao Yaolong
Published: June 2021

Land use land cover (LULC) transition analysis is a systematic approach that helps in understanding physical and human involvement in the natural environment and sustainable development. The study of the spatiotemporal shifting pattern of LULC, the simulation of future scenarios and the intensity analysis at the interval, category and transition levels provide a comprehensive prospect to determine current and future development scenarios. In this study, we used multitemporal remote sensing data from 1980–2020 with a 10-year interval, explanatory variables (Digital Elevation Model (DEM), slope, population, GDP, distance from roads, distance from the city center and distance from streams) and an integrated CA-ANN approach within the MOLUSCE plugin of QGIS to model the spatiotemporal change transition potential and future LULC simulation in the Greater Bay Area. The results indicate that physical and socioeconomic driving factors have significant impacts on the landscape patterns. Over the last four decades, the study area experienced rapid urban expansion (4.75% to 14.75%), resulting in the loss of forest (53.49% to 50.57%), cropland (21.85% to 16.04%) and grassland (13.89% to 12.05%). The projected results (2030–2050) also endorse the increasing trend in built-up area, forest, and water at the cost of substantial amounts of cropland and grassland.
Groundwater-Extracting Rice Production in the Rejoso Watershed (Indonesia) Reducing Urban Water Availability: Characterisation and Intervention Priorities
Authors: Khasanah Ni’matul , Tanika Lisa , Pratama Lalu Deden Yuda , Leimona Beria , Prasetiyo Endro , Marulani Fitri , Hendriatna Adis , Zulkarnain Mukhammad Thoha , Toulier Alix , van Noordwijk Meine
Published: June 2021

Production landscapes depend on, but also affect, ecosystem services. In the Rejoso watershed (East Java, Indonesia), uncontrolled groundwater use for paddies reduces flow of lowland pressure-driven artesian springs that supply drinking water to urban stakeholders. Analysis of the water balance suggested that the decline by about 30% in spring discharge in the past decades is attributed for 47 and 53%, respectively, to upland degradation and lowland groundwater abstraction. Consequently, current spring restoration efforts support upland agroforestry development while aiming to reduce lowland groundwater wasting. To clarify spatial and social targeting of lowland interventions five clusters (replicable patterns) of lowland paddy farming were distinguished from spatial data on, among other factors, reliance on river versus artesian wells delivering groundwater, use of crop rotation, rice yield, fertiliser rates and intensity of rodent control. A survey of farming households (461 respondents), complemented and verified through in-depth interviews and group discussions, identified opportunities for interventions and associated risks. Changes in artesian well design, allowing outflow control, can support water-saving, sustainable paddy cultivation methods. With rodents as a major yield-reducing factor, solutions likely depend on more synchronized planting calendars and thus on collective action for effectiveness at scale. Interventions based on this design are currently tested.
Building Information Modeling in Quebec’s Procurement for Public Infrastructure: A Case for Integrated Project Delivery
Authors: Jobidon Gabriel , Lemieux Pierre , Beauregard Robert
Published: June 2021

The Province of Quebec is currently in the process of adopting building information modeling (BIM) for major infrastructure projects. However, legal and contractual concerns such as the tendering process, adjudication criteria, intellectual property and risk–reward sharing mechanisms hinder the implementation of an efficient BIM process. This paper addresses the following question: How do norms, whether legislative, regulatory or contractual, functionally or dysfunctionally affect the effective implementation of BIM in Quebec’s public infrastructure framework? This paper suggests that the use of Integrated Project Delivery (IPD) should help mitigate legal barriers hindering BIM implementation, while preserving balance between fairness and encouraging collaboration. Quebec’s normative framework, which includes legislation, regulations, contracts and infra-regulatory rules, should be modified to standardize collaborative mechanisms, integrate two-stage negotiated processes such as rank-and-run or best and final offer and enable the assessment of tenderers’ objective qualities and more subjective qualities. Furthermore, a risk–reward sharing mechanism should be implemented through target costing, and upstream participation from a wide range of stakeholders should be encouraged.
Effect of Sit-to-Stand Training Combined with Taping on Spasticity, Strength, Gait Speed and Quality of Life in Patients with Stroke: A Randomized Controlled Trial
Authors: In Tae-sung , Jung Jin-hwa , Jung Kyoung-sim , Cho Hwi-young
Published: June 2021

Background and Objectives: Spasticity is one of the factors that make it more difficult to control posture in stroke patients. Taping has been used to manage muscle stiffness in various musculoskeletal disorders. Recently, it has been used to decrease spasticity in stroke patients, but the effect of taping combined with therapeutic exercise is still unclear. The purpose of the present study was to determine whether the sit-to-stand (STS) training combined with taping improves the ankle spasticity, muscle strength, gait speed, and quality of life in stroke patients. Material and Methods: The study recruited 40 stroke patients, who were randomly divided into two groups: the taping and STS training (TSTS) group (n = 20) and the STS group (n = 20). The subjects in the TSTS group underwent STS training with Kinesio taping on the tibialis anterior, calf and ankle joint, whereas the subjects in the STS group underwent only STS training. All participants underwent 30 sessions of STS training (30 minutes, 5 days per week for 6 weeks). The present study evaluated the spasticity of ankle plantar flexors by the mean of the composite spasticity score; the muscle strength and gait speed were evaluated using the handheld dynamometer and the 10-meter walk test, respectively, and the quality of life was assessed using the stroke-specific quality of life scale. Result: The TSTS group and the STS group showed significant improvements in spasticity, muscle strength, walking speed, and quality of life after the intervention (p < 0.05). The level of improvement in the TSTS group was significantly higher in spasticity, muscle strength, and walking speed compared to the STS group (p < 0.05). Conclusions: The present study demonstrated that STS training is effective for decreasing spasticity in stroke patients and suggested that additional taping intervention further improved this effect. In addition, improvement of muscle strength and gait function was observed with a significant decrease of ankle spasticity.
Mechanosensitive TRPV4 Channel-Induced Extracellular ATP Accumulation at the Acupoint Mediates Acupuncture Analgesia of Ankle Arthritis in Rats
Authors: Zheng Yawen , Zuo Weimin , Shen Dan , Cui Kaiyu , Huang Meng , Zhang Di , Shen Xueyong , Wang Lina
Published: June 2021

(1) Background: Acupuncture (AP) is a safe and effective analgesic therapy. Understanding how fine needles trigger biological signals can help us optimize needling manipulation to improve its efficiency. Adenosine accumulation in treated acupoints is a vital related event. Here, we hypothesized that extracellular ATP (eATP) mobilization preceded adenosine accumulation, which involved local activation of mechanosensitive channels, especially TRPV4 protein. (2) Methods: AP was applied at the injured-side Zusanli acupoint (ST36) of acute ankle arthritis rats. Pain thresholds were assessed in injured-side hindpaws. eATP in microdialysate from the acupoints was determined by luminescence assay. (3) Results: AP analgesic effect was significantly suppressed by pre-injection of GdCl3 or ruthenium red in ST36, the wide-spectrum inhibitors of mechanosensitive channels, or by HC067047, a specific antagonist of TRPV4 channels. Microdialysate determination revealed a needling-induced transient eATP accumulation that was significantly decreased by pre-injection of HC067047. Additionally, preventing eATP hydrolysis by pre-injection of ARL67156, a non-specific inhibitor of ecto-ATPases, led to the increase in eATP levels and the abolishment of AP analgesic effect. (4) Conclusions: These observations indicate that needling-induced transient accumulation of eATP, due to the activation of mechanosensitive TRPV4 channels and the activities of ecto-ATPases, is involved in the trigger mechanism of AP analgesia.
Spatiotemporal 22q11.21 Protein Network Implicates DGCR8-Dependent MicroRNA Biogenesis as a Risk for Late Fetal Cortical Development in Psychiatric Diseases
Authors: Chen Liang , Cai Wenxiang , Wang Weidi , Liu Zhe , Lin Guan-Ning
Published: June 2021

The chromosome 22q11.21 copy number variant (CNV) is a vital risk factor that can be a genetic predisposition to neurodevelopmental disorders (NDD). As the 22q11.21 CNV affects multiple genes, causal disease genes and mechanisms affected are still poorly understood. Thus, we aimed to identify the most impactful 22q11.21 CNV genes and the potential impacted human brain regions, developmental stages and signaling pathways. We constructed the spatiotemporal dynamic networks of 22q11.21 CNV genes using the brain developmental transcriptome and physical protein–protein interactions. The affected brain regions, developmental stages, driver genes and pathways were subsequently investigated via integrated bioinformatics analysis. As a result, we first identified that 22q11.21 CNV genes affect the cortical area mainly during late fetal periods. Interestingly, we observed that connections between a driver gene, DGCR8, and its interacting partners, MECP2 and CUL3, also network hubs, only existed in the network of the late fetal period within the cortical region, suggesting their functional specificity during brain development. We also confirmed the physical interaction result between DGCR8 and CUL3 by liquid chromatography-tandem mass spectrometry. In conclusion, our results could suggest that the disruption of DGCR8-dependent microRNA biogenesis plays a vital role in NDD for late fetal cortical development.
Test and Numerical Model of Curved Steel–Concrete Composite Box Beams under Positive Moments
Authors: Liu Zhi-Min , Huo Xue-Jin , Wang Guang-Ming , Ji Wen-Yu
Published: June 2021

Compared with straight steel–concrete composite beams, curved composite beams exhibit more complicated mechanical behaviors under combined bending and torsion coupling. There are much fewer experimental studies on curved composite beams than those of straight composite beams. This study aimed to investigate the combined bending and torsion behavior of curved composite beams. This paper presents static loading tests of the full elastoplastic process of three curved composite box beams with various central angles and shear connection degrees. The test results showed that the specimens exhibited notable bending and torsion coupling force characteristics under static loading. The curvature and interface shear connection degree significantly affected the force behavior of the curved composite box beams. The specimens with weak shear connection degrees showed obvious interfacial longitudinal slip and transverse slip. Constraint distortion and torsion behavior caused the strain of the inner side of the structure to be higher than the strain of the outer side. The strain of the steel beam webs was approximately linear. In addition, fine finite element models of three curved composite box beams were established. The correctness and applicability of the finite element models were verified by comparing the test results and numerical calculation results for the load–displacement curve, load–rotational angle curve, load–interface slip curve, and cross-sectional strain distribution. Finite element modeling can be used as a reliable numerical tool for the large-scale parameter analysis of the elastic–plastic mechanical behavior of curved composite box beams.
Effect of Welding Peak Temperature on Microstructure and Impact Toughness of Heat-Affected Zone of Q690 High Strength Bridge Steel
Authors: Zhang Yue , Xiao Jun , Liu Wei , Zhao Aimin
Published: June 2021

The effect of peak temperature (TP) on the microstructure and impact toughness of the welding heat-affected zone (HAZ) of Q690 high-strength bridge steel was studied using a Gleeble-3500 thermal simulation testing machine. The results show that the microstructure of the inter critical heat-affected zone (ICHAZ) was ferrite and bainite. The microstructure of fine grain heat-affected zone (FGHAZ) and coarse grain heat-affected zone (CGHAZ) was lath bainite (LB), lath martensite (LM), and granular bainite (GB), but the microstructure of FGHAZ was finer. With the increase in peak temperature, the content of LB and GB decreased, the content of LM increased, and the lath bundles of LM and LB gradually became coarser. With the increase in peak temperature, the grain size of the original austenite increased significantly, and the impact toughness decreased significantly. When the peak temperature was 800 °C, the toughness was the best. For CGHAZ, the peak temperature should be less than 1200 °C to avoid excessive growth of grain and reduction of mechanical property.
Experimental Verification of Contact Acoustic Nonlinearity at Rough Contact Interfaces
Authors: Kim Youngbeom , Choi Sungho , Jhang Kyung-Young , Kim Taehyeon
Published: June 2021

When a longitudinal wave passes through a contact interface, second harmonic components are generated due to contact acoustic nonlinearity (CAN). The magnitude of the generated second harmonic is related to the contact state of the interface, of which a model has been developed using linear and nonlinear interfacial stiffness. However, this model has not been sufficiently verified experimentally for the case where the interface has a rough surface. The present study verifies this model through experiments using rough interfaces. To do this, four sets of specimens with different interface roughness values (Ra = 0.179 to 4.524 μm) were tested; one set consists of two Al6061-T6 blocks facing each other. The second harmonic component of the transmitted signal was analyzed while pressing on both sides of the specimen set to change the contact state of the interface. The experimental results showed good agreement with the theoretical prediction on the rough interface. The magnitude of the second harmonic was maximized at a specific contact pressure. As the roughness of the contact surface increased, the second harmonic was maximized at a higher contact pressure. The location of this maximal point was consistent between experiments and theory. In this study, an FEM simulation was conducted in parallel and showed good agreement with the theoretical results. Thus, the developed FEM model allows parametric studies on various states of contact interfaces.
Electrospun Nanofibers and Electrochemical Techniques for the Detection of Heavy Metal Ions
Authors: Malara Angela , Fotia Antonio , Paone Emilia , Serrano Giulia
Published: June 2021

Contamination by heavy metals is currently one of the most environmental concerns especially due to the toxicity, pervasiveness, and persistence of these substances. As they are not biodegradable, heavy metals are harmful not only for water, air, and soil but also for human health, even in very low traces. There is therefore a pressing need to develop an efficient, economic, and rapid analysis method to be applied in a wide range of conditions and able to detect very low contaminants concentrations. Currently, the most novel solution in this field is represented by the combination of electrospun nanofibers and highly sensitive electrochemical techniques. It has been proved that nanofibers, due to their outstanding properties, perfectly fit as sensing material when trace concentrations of heavy metals were investigated by anodic stripping voltammetry, envisaged as the most sensitive electrochemical technique for this kind of measurements. This work aims to provide an overview of the latest trends in the detection of contaminants by the simultaneous use of electrospun fibers and anodic stripping voltammetry. Indeed, a clear and comprehensive vision of the current status of this research may drive future improvements and new challenges.
Fabrication of a Micron-Scale Three-Dimensional Single Crystal Diamond Channel Using a Micro-Jet Water-Assisted Laser
Authors: Wei Qiang , Zhang Xiaofan , Lin Fang , Wang Ruozheng , Chen Genqiang , Wang Hong-Xing
Published: June 2021

Two types of a trench with conventional vertical and new reverse-V-shaped cross-sections were fabricated on single crystal diamond (SCD) substrate using a micro-jet water-assisted laser. In addition, a microwave plasma chemical vapor deposition device was used to produce multiple micrometer-sized channels using the epitaxial lateral overgrowth technique. Raman and SEM methods were applied to analyze both types of growth layer characterization. The hollowness of the microchannels was measured using an optical microscope. According to the findings, the epitaxial lateral overgrowth layer of the novel reverse-V-shaped trench produced improved SCD surface morphology and crystal quality.
Simulation of the Attrition of Recycled Concrete Aggregates during Concrete Mixing
Authors: Moreno-Juez Jaime , Tavares Luís Marcelo , Artoni Riccardo , Carvalho Rodrigo M. de , da Cunha Emerson Reikdal , Cazacliu Bogdan
Published: June 2021

Concrete mixing can lead to mechanical degradation of aggregates, particularly when dealing with recycled concrete aggregates. In this work, the attrition of such materials during mixing is studied by means of experiments and simulations. The effect of the presence of fines, water addition, flow configuration of the mixer (co- or counter-current) and impeller frequency is discussed. Experiments were performed in a laboratory Eirich mixer. Discrete element numerical simulations (DEM) were performed on the same geometry by mimicking the behaviour of the material and, in particular, the cohesion induced by water and the cement paste using either Hertz–Mindlin or Hertz–Mindlin with Johnson–Kendall–Roberts (JKR) contact laws. The combination of the collision energy spectra extracted from the DEM simulations and an attrition model allowed the prediction of the mass loss due to attrition in 1-min experiments. Semi-quantitative agreement was observed between experiments and simulations, with a mean relative error of 26.4%. These showed that higher mass losses resulted from operation at the highest impeller speeds, co-current operation, and also with the wet aggregate. Mixing of the agglomerate in the concrete mix resulted in a significant reduction in attrition when compared to mixing aggregates alone. With further validation, the proposed simulation approach can become a valuable tool in the optimization of mixing by allowing the effects of material, machine and process variables to be studied on the mass loss due to attrition.
Numerical Solution of Two Dimensional Time-Space Fractional Fokker Planck Equation With Variable Coefficients
Authors: Mahmoud Elsayed I. , Orlov Viktor N.
Published: June 2021

This paper presents a practical numerical method, an implicit finite-difference scheme for solving a two-dimensional time-space fractional Fokker–Planck equation with space–time depending on variable coefficients and source term, which represents a model of a Brownian particle in a periodic potential. The Caputo derivative and the Riemann–Liouville derivative are considered in the temporal and spatial directions, respectively. The Riemann–Liouville derivative is approximated by the standard Grünwald approximation and the shifted Grünwald approximation. The stability and convergence of the numerical scheme are discussed. Finally, we provide a numerical example to test the theoretical analysis.
Improved Failure Mode and Effect Analysis: Implementing Risk Assessment and Conflict Risk Mitigation with Probabilistic Linguistic Information
Authors: Du Zhi-Jiao , Chen Zhi-Xiang , Yu Su-Min
Published: June 2021

Failure mode and effect analysis (FMEA) is a system reliability analysis technique that has been widely used in various industries to reduce the failure risk of products, systems, and services. However, traditional FMEA methods have limitations in managing the complex uncertain environment as well as the aggregation and weight allocation of FMEA attributes. Complex real-world problems usually involve multiple decision-makers. Individual perceptions and subjective factors are likely to lead to the differences in opinion, and even the conflict risk, which can ultimately become a challenge to achieve a highly recognized solution. This paper proposes an improved FMEA method to implement the risk assessment, which integrates probabilistic linguistic information and conflict risk mitigation. Probabilistic linguistic term sets (PLTSs) are used to describe the risk assessments, and a comprehensive method is applied to determine the weights of the FMEA attributes. Several new operations and distance measures related to PLTSs are defined. Then, a conflict risk mitigation model is developed to reduce the differences among decision-makers’ FMEA risk assessments. Finally, a case study on global production base selection is presented to illustrate the feasibility and effectiveness of the proposed method. Comparative analysis and discussion verify features and advantages of the method.
Microstructure Evaluation, Quantitative Phase Analysis, Strengthening Mechanism and Influence of Hybrid Reinforcements (β-SiCp, Bi and Sb) on the Collective Mechanical Properties of the AZ91 Magnesium Matrix
Authors: Huang Song-Jeng , Diwan Midyeen Sikkanthar , Subramani Murugan , Chiang Chao-Ching
Published: June 2021

Gravitational melt-stir casting produced hybrid nano-reinforcements (β-SiCp) and micro-reinforcements (Bi and Sb) of AZ91 composites. SiCp-diffused discontinuous β-Mg17Al12 precipitation with a vital factor of SiC was exhibited at the grain boundary region, formulated Mg3Si throughout the composite and changed the present Mg0.97Zn0.03 phases. The creation of Mg2Si (cubic) and SiC (rhombohedral axes) enhanced the microhardness by 18.60% in a 0.5 wt.% SiCp/AZ91 matrix. The microhardness of 1 wt.% SiCp/AZ91 was slightly reduced after Mg0.97Zn0.03 (hexagonal) reduction. The best ultimate tensile value obtained was about 169.33 MPa (increased by 40.10%) in a 0.5 wt.% SiCp/AZ91 matrix. Microelements Bi and Sb developed Mg3Bi2, Mg3Sb2 and monoclinic C60 phases. The best peak yield strength of 82.75 MPa (increased by 19.85%) was obtained with the addition of 0.5 wt.% SiCp/1 wt.% Bi/0.4 wt.% Sb. The mismatch of the coefficient of thermal expansion of segregated particles and the AZ91 matrix, the shear transfer effect and the Orowan effect, combined with the quantitative value of phase existence, improved the compressive strengths of the composites with 0.5 wt.% β-SiCp, 1 wt.% β-SiCp and 0.5 wt.% SiCp/1 wt.% Bi/0.4 wt.% Sb by 2.68%, 6.23% and 8.38%, respectively. Notably, the Charpy impact strengths of 0.5 wt.% and 1 wt.% β-SiCp-added AZ91 composites were enhanced by 236% (2.89 J) and 192% (2.35 J), respectively. The addition of Bi and Sb with SiCp resulted in the formation of a massive phase of brittle Al6Mn. Al–Mn-based phases (developed huge voids and cavities) remarkably reduced impact values by 80% (0.98 J). The discussion covers the quantitative analyses of X-ray diffraction, optical microscopy and scanning electron microscopy results and fracture surfaces.
Removal of Sb Impurities in Copper Electrolyte and Evaluation of As and Fe Species in an Electrorefining Plant
Authors: González de las Torres Ana , Moats Michael , Ríos Guillermo , Rodríguez Almansa Ana , Sánchez-Rodas Daniel
Published: June 2021

Antimony and arsenic concentrations and their oxidation states (Sb(III), Sb(V), As(III) and As(V)) in copper electrorefining electrolyte can affect copper cathode quality through the formation of floating slimes. A laboratory-scale pilot plant was operated to remove Sb from commercial electrolyte. The pilot plant consisted of a pre-treatment process with copper shavings followed by ion exchange. The results indicated that Sb(III) was removed from copper electrolyte completely, while Sb(V) was partially eliminated. The concentrations of As(III) and As(V) were not affected, and the poisoning of the ion exchange resin by Fe(III) was avoided by pre-reduction to Fe(II) by copper shavings. The operation configuration of the pilot plant was applied to the design of an industrial plant for Sb/Bi removal at the Atlantic Copper Refinery in Huelva, Spain. The evolution of Sb, Fe and As species in the commercial electrolyte was monitored prior to and after the installation of the Sb/Bi removal plant. The results show a ca. 45% decrease in total Sb content (from 0.29 g L−1 to 0.16 g L−1) in the electrolyte. This reduction is more noticeable for Sb(III), whose concentration decreased from 0.18 g L−1 to 0.09 g L−1, whereas Sb(V) concentration diminished from 0.11 g L−1 to 0.07 g L−1. The resin also retained ca. 75% of the Bi content (0.15–0.22 g L−1). The total As increased during the study period (from 7.7 to 9.0 g L−1) due to changes in plant inputs. Arsenic was predominantly As(V) (ca. 93–95%). The total Fe concentration experienced little variation (0.9–1.1 g L−1) with Fe(II) being the main species (ca. 94–96%).
Microstructure and Magnetic Properties of Selected Laser Melted Ni-Mn-Ga and Ni-Mn-Ga-Fe Powders Derived from as Melt-Spun Ribbons Precursors
Authors: Maziarz Wojciech , Czaja Paweł , Chulist Robert , Wójcik Anna , Żrodowski Łukasz , Morończyk Bartosz , Wróblewski Rafał , Kowalczyk Maciej
Published: June 2021

Selective Laser Melting was successfully used as a fabrication method to produce Ni-Mn-Ga and Ni-Mn-Ga-Fe ferromagnetic shape memory alloys. The starting material in a powder form with an average particle size of about 17.6 µm was produced by milling of as melt-spun ribbons. The microstructure, phase composition, and martensitic transformation behavior of both powder precursors and laser melted alloys were investigated by several methods, including high energy X-ray diffraction, electron microscopy, and vibrating sample magnetometry. The as laser melted materials are chemically homogenous and show a typical layered microstructure. Both alloy compositions have a duplex structure consisting either of austenite and 10M martensite (Ni-Mn-Ga) or a mixture of 14M and NM martensitic phases (Ni-Mn-Ga-Fe), contrary to the as milled powder precursors showing fcc structure in both cases. The forward martensitic transformation takes place at 336 and 325 K for Ni-Mn-Ga and Ni-Mn-Ga-Fe, respectively, while the magnetic response is much stronger for Ni-Mn-Ga than for the quaternary alloy. The results show that Selective Laser Melting allows for producing of good quality, homogenous materials. However, their microstructural features and consequently shape memory behavior should be tailored by additional heat treatment.
Hydrogen-Assisted Cracking in GMA Welding of High-Strength Structural Steel—A New Look into This Issue at Narrow Groove
Authors: Schaupp Thomas , Schroeder Nina , Schroepfer Dirk , Kannengiesser Thomas
Published: June 2021

Modern arc processes, such as the modified spray arc (Mod. SA), have been developed for gas metal arc welding of high-strength structural steels with which even narrow weld seams can be welded. High-strength joints are subjected to increasingly stringent requirements in terms of welding processing and the resulting component performance. In the present work, this challenge is to be met by clarifying the influences on hydrogen-assisted cracking (HAC) in a high-strength structural steel S960QL. Adapted samples analogous to the self-restraint TEKKEN test are used and analyzed with respect to crack formation, microstructure, diffusible hydrogen concentration and residual stresses. The variation of the seam opening angle of the test seams is between 30° and 60°. To prevent HAC, the effectiveness of a dehydrogenation heat treatment (DHT) from the welding heat is investigated. As a result, the weld metals produced at reduced weld opening angle show slightly higher hydrogen concentrations on average. In addition, increased micro- as well as macro-crack formation can be observed on these weld metal samples. On all samples without DHT, cracks in the root notch occur due to HAC, which can be prevented by DHT immediately after welding.
Lateral-Type Spin-Photonics Devices: Development and Applications
Authors: Nishizawa Nozomi , Munekata Hiro
Published: June 2021

Spin-photonic devices, represented by spin-polarized light emitting diodes and spin-polarized photodiodes, have great potential for practical use in circularly polarized light (CPL) applications. Focusing on the lateral-type spin-photonic devices that can exchange CPL through their side facets, this review describes their functions in practical CPL applications in terms of: (1) Compactness and integrability, (2) stand-alone (monolithic) nature, (3) room temperature operation, (4) emission with high circular polarization, (5) polarization controllability, and (6) CPL detection. Furthermore, it introduces proposed CPL applications in a wide variety of fields and describes the application of these devices in biological diagnosis using CPL scattering. Finally, it discusses the current state of spin-photonic devices and their applications and future prospects.
An Electrostatic Self-Excited Resonator with Pre-Tension/Pre-Compression Constraint for Active Rotation Control
Authors: Yun Ruide , Zhu Yangsheng , Liu Zhiwei , Huang Jianmei , Yan Xiaojun , Qi Mingjing
Published: June 2021

We report a novel electrostatic self-excited resonator driven by DC voltage that achieves variable velocity-position characteristics via applying the pre-tension/pre-compression constraint. The resonator consists of a simply supported micro-beam, two plate electrodes, and two adjustable constraint bases, and it can be under pre-compression or pre-tension constraint by adjusting the distance L between two constraint bases (when beam length l > L, the resonator is under pre-compression and when l < L, it is under pre-tension). The oscillating velocity of the beam reaches the maximum value in the position around electrodes under the pre-compression constraint and reaches the maximum value in the middle position between two electrodes under the pre-tension condition. By changing the constraint of the microbeam, the position of the maximum velocity output of the oscillating beam can be controlled. The electrostatic self-excited resonator with a simple constraint structure under DC voltage has great potential in the field of propulsion of micro-robots, such as active rotation control of flapping wings.
Innovative Approach to Fast Electron Microscopy Using the Example of a Culture of Virus-Infected Cells: An Application to SARS-CoV-2
Authors: Le Bideau Marion , Wurtz Nathalie , Baudoin Jean-Pierre , La Scola Bernard
Published: June 2021

Despite the development of new diagnostic methods, co-culture, based on sample inoculation of cell monolayers coupled with electron microscopy (EM) observation, remains the gold standard in virology. Indeed, co-culture allows for the study of cell morphology (infected and not infected), the ultrastructure of the inoculated virus, and the different steps of the virus infectious cycle. Most EM methods for studying virus cycles are applied after infected cells are produced in large quantities and detached to obtain a pellet. Here, cell culture was performed in sterilized, collagen-coated single-break strip wells. After one day in culture, cells were infected with SARS-CoV-2. Wells of interest were fixed at different time points, from 2 to 36 h post-infection. Microwave-assisted resin embedding was accomplished directly in the wells in 4 h. Finally, ultra-thin sections were cut directly through the infected-cell monolayers. Our methodology requires, in total, less than four days for preparing and observing cells. Furthermore, by observing undetached infected cell monolayers, we were able to observe new ultrastructural findings, such as cell–cell interactions and baso-apical cellular organization related to the virus infectious cycle. Our innovative methodology thus not only saves time for preparation but also adds precision and new knowledge about viral infection, as shown here for SARS-CoV-2.