bluuebunny/crossref_metadata_2025 huggingface dataset:
Theoretical Derivation of Gauges for Straddle-type Monorail Vehicle
Authors: Zou Jiancai , Chen Bingyan , Zhan Shen , Huang Chao , Wang Xiaojun
Published: May 2021

The theoretical model of the straddle-type monorail vehicle bogie is set up and the function of each component is introduced. The lateral and vertical displacements of carbody when the lateral and roll motion of carbody in the same/reverse direction are attained through theoretical derivation, which can be put into the calculation of the vehicle gauge. A computational program is written to simulate the corresponding results under specific parameters. The correctness of the method to calculate the monorail vehicle gauge is verified.
Research on the Impact of Cloud Manufacturing Platform Pricing Strategies on the Profit of Single Channel Suppliers
Authors: Sun Daohe , Yang Xin , Chen Zixing
Published: May 2021

Based on the Hotelling model, this paper compares the profit of single-channel transactions between the cloud supplier on the cloud manufacturing platform and the offline supplier with the manufacturer. It studies how the cloud manufacturing platform formulates the transaction charging coefficient so that the profit of the cloud supplier is greater than the profit of the offline supplier and guarantees its own profit, thereby attracting more suppliers to the cloud. And further consider the impact on supplier profit and cloud manufacturing platform revenue when the manufacturer’s value perception coefficient changes, provide reasonable suggestions for cloud manufacturing platform pricing, and provide cloud suppliers with strategies to attract manufacturers.
A charging pricing method for electric vehicles on freeways considering charging demands and strategy
Authors: Chen Lixing , Ji Zhenya , Han Xiaoxin , Wang Qi
Published: May 2021

The effective electric vehicles (EVs) charging price is one of economic incentive approaches for implementation of charging strategy for EVs on freeways. An EVs charging pricing method is proposed by considering the EV charging demands and strategy. The busy and idle charging capacities model, and busy and idle charging prices model are established to test the proposed method effectiveness. The charging of EVs on freeways, under different charging strategies, is simulated by queuing model and queuing algorithm according to related data, and the paper verifies the proposed method.
Research on Distributed Power Quality Monitoring System of Large Centralized Charging Station
Authors: Liu Zhikai , Zhang Yang , Zheng Wenyue , Li Haihong , Wu Gang
Published: May 2021

The power quality problems of large-scale centralized charging stations are prominent, affecting the operation of the station equipment and the power grid, and a simple and efficient distributed power quality monitoring system is required. Based on the analysis of large-scale centralized charging stations for distributed power quality monitoring system requirements, this paper studies the overall structure of the distributed monitoring system, and analyzes the functional requirements of each part of the monitoring system, and gives the voltage/current power quality Monitoring terminal functions and key device design; by comparing and analyzing the characteristics of various communication technologies, an optimal solution for the communication of the distributed monitoring system in the charging station is given. The proposed system provides a basis for real-time monitoring of multiple monitoring terminals in large-scale centralized charging stations, analysis and timely release of relevant power quality assessment information, and in-depth study of the power quality of various charging piles in the charging station and their mutual influence. At the same time, the formed “point-line-surface” charging station monitoring system can provide a data basis for smart operation and maintenance of charging stations.
Simulation and Experiment Research on Dynamic Stress of 21kV Equivalent Prototype of 500kV Current Limiter High Coupled Split Reactor
Authors: Chu Bo , Liu Zhanpeng , Tang Qiang , Wang Peiren , Yu Wenbo , Jia Shenli , Xiu Shixin
Published: May 2021

The dynamic stress simulation and experiment of the 21kV equivalent prototype of the 500kV current limiter high coupled split reactor are researched in this paper. A calculation model of dynamic stress of 21kV equivalent prototype of 500kV current limiter high coupled split reactor is established by using finite element simulation software, and the dynamic stress distribution is analysed with the calculation results. Then the dynamic stability experiments of the single arm of the prototype and analysis of the experiment and simulation results are introduced. The results of simulation and experiment prove that both of the dynamic stability of the 21kV equivalent prototype and the 500kV current limiter high coupled split reactor meet the design requirement.
The Influence to Uniform Current Distribution of SiC MOSFET Modules Based on the 3rd Quadrant Characteristics
Authors: Lu Wenhao , Wan Caiping , Zhang Xizi , Du Yujie , Ge Niannian , Xu Hengyu , Ye Tianchun
Published: May 2021

This paper concentrated on the 3rd quadrant characteristics of 1200V/300A full SiC MOSFET modules produced by four SiC mainstream manufacturers; and compared the diode forward voltage (VSD) performances of “SiC MOSFET only” and SiC MOSFETs modules with SiC Schottky barrier parallel diode. The characteristics of the diode forward voltage showed that module A exhibits the same trend with the PiN diode, whereas modules B, C and D exhibit the characteristics of SBD. Through the failure analysis, it was verified that there is no parallel SBD in module A, meanwhile, it was assumed that modules B, C and D integrate a positive temperature characteristic SBD by wire bonding. The existence of SBD can prevent the modules from burning out due to excessive heating caused by non-uniform current distribution. From the analysis, it illustrated that the body diode can be used as the parallel SiC SBD, but further research on the uniform current distribution of the the body diode is needed.
Study on waste heat measurement and composition change of Pd conductor after laser stimulation in H2 gas-loading system
Authors: Shen Bingjun , Yang Huiru , Wang Xingye , Jin Lihong , Tian Jian
Published: May 2021

This study mainly involves that palladium hydride with different gas-loading ratio is stimulated by YAG frequency doubling laser (λ=532nm) in H/Pd gas-loading system to produce excess heat. The range of hydrogen loading ratio of palladium hydride is 0 to 0.8. The results show that the waste heat is produced in the experiment stimulated by laser. When the hydrogen loading ratio in Pd is 0.3±0.01, the maximum waste heat produced by the system within 1 hour is about 120.91±0.47 J. Some new elements are produced on the surface of Pd samples, including Si, Al, Ca and some others, these elements were found in local locations by scanning electron microscopy and energy spectrum analysis. This suggests that some reactions may have taken place in the experiment.
De-oiling Test of New Type Cyclone for Treatment of Wastewater Containing Polymer
Authors: Wang Qiang , Li Guisheng , Li Deqiang , Li Gang , Zhang Jun , Zhong Xingfu
Published: May 2021

When the polymer concentration in the produced fluid increases, the viscosity of the sewage will increase, the overall flow velocity of the fluid in the cyclone will decrease, the kinetic energy will decrease, the wall friction resistance will increase, and the tangential velocity will decrease overall. The performance of the cyclone is degraded. The structure and parameters need to be adjusted and optimized. By optimizing the design of the structure and parameters of the inlet fluid channel, the oil-receiving port, etc., a new type of oil-water cyclone is designed. Numerical experiments show that the new type of oil-water cyclone is effective for the separation of low oil content of polymer-containing sewage. Through indoor experiments and on-site pilot scale-up, 5# cyclone was modified with a new type of oil-water cyclone in the West II Joint Processing Station. The field test and production daily report data show that the improved 5# cyclone is effective. The polymer-containing sewage treatment can obtain stable results. The oil content of the effluent is better than the original cyclone indicator. When the oil content of the polymer-containing sewage at the inlet is 100-300mg/l, the average oil content of the outlet is less than 100mg/l, Meets the design requirements, indicating that the improved cyclone structure and parameters are suitable for the treatment of polymer-containing sewage, and the newly designed cyclone is effective for the treatment of polymer-containing wastewater.
Forecasting on China’s Water Demand by Industry in 2021
Authors: Liu Xiuli , Qin Minghui , Xiang Xin
Published: May 2021

Forecasting of demand for water in advance is critical for water supply planning. The paper made water consumption analysis by industry in China. With multiple regression analysis, time series analysis and expert experience methods, the water demand by industry in China in 2021 was forecasted. The results show that the total demand of water in China in 2020 will be about 598.06 billion cubic meters, slightly less than that in 2020. Among them, the agricultural water demand would account for about 61.1%, the industrial water demand account for about 19.6%. For the domestic and the environmental water demand, the proportion would be 15.1% and 4.2% respectively.
Numerical design of a high efficiency and ultra-broadband terahertz cross-polarization converter
Authors: Cao Thanh Nghia , Nguyen Minh Tam , Hieu Nguyen Ngoc , Truong Chi Lam , Nguyen Thi Quynh Hoa
Published: May 2021

A simple design of terahertz polarization converter has attracted great attention owing to the applicability of terahertz technology in broad fields such as imaging, non-destructive sensing, and communications, but remains a key challenge to simultaneously achieve both wide bandwidth and high conversion efficiency. Here we report a single-layer metasurface-based polarization converter formed by a combination of different resonator shapes that realizes cross-polarization conversion and achieves an ultra-broadband and high conversion efficiency with a wide oblique incidence in the terahertz region from 1.35 THz to 3.55 THz. The high performance and physical mechanism attributed to both electric and magnetic resonances of this proposed structure are guaranteed and analyzed by numerical study. Our design structure provides the frequency tunability to other frequency bands and possesses promising applications in terahertz polarization-control devices.
How many hot days and heavy precipitation days will grandchildren experience that break the records set in their grandparents’ lives?
Authors: Shiogama Hideo , Fujimori Shinichiro , Hasegawa Tomoko , Takahashi Kiyoshi , Kameyama Yasuko , Emori Seita
Published: May 2021

One of the major barriers to climate communication is that climate change is often presented to the public in such a way that impacts seem distant in time. To improve how climate change resonates with people, we propose a simple indicator: how many extreme events (hot days and heavy precipitation days) are grandchildren projected to experience that their grandparents will not experience in their lives? We analyse the Coupled Model Intercomparison Project Phase 6 ensemble. During grandchildren’s lifetime (2020–2100) under the shared socioeconomic pathway 5–8.5 (SSP5-8.5), in some tropical regions, they are projected to experience >1000 hot days and >5 heavy precipitation days breaking records set in their grandparents’ lifetime until 2040. These numbers of unprecedented hot days and heavy precipitation days under SSP5-8.5 are greater in countries with lower CO2 emissions and income per capita than in countries with higher CO2 emissions and income per capita. We show that not only the numbers of unprecedented hot days and heavy precipitation days but also their unevenness across countries can be significantly lowered in the SSP1-2.6 scenario, which is consistent with the 2 °C goal of the Paris Agreement. This new approach would help adults easily understand how their climate change mitigation efforts could decrease the unprecedented extreme events during youths’ lifetime and reduce the intergenerational and intragenerational inequalities regarding extreme events.
Investigation of manufacturing defects in 3D-printed CFRP using laser ultrasonic testing and x-ray micro-computed tomography
Authors: Cho Sang-Yeon , Lee Jung-Ryul
Published: May 2021

3D-printed carbon fiber reinforced plastic (CFRP) composites have attracted significant attention due to their design flexibility and low manufacturing cost. However, 3D-printed CFRP contains inherent defects that occur during the manufacturing process. As the manufacturing defects are likely to degrade the mechanical performance of the 3D-printed CFRP, these defects require extensive investigation. Typically, x-ray micro-computed tomography (micro-CT) is used to detect manufacturing defects, but as micro-CT cannot be applied to large structures, the laser ultrasonic testing (LUT) method has been proposed. In this study, two specimens with different stacking sequences were manufactured using a continuous fiber 3D printer. The two specimens were then inspected using LUT and micro-CT. The manufacturing defects were successfully visualized using LUT, and similar defects were detected in the micro-CT inspection results. The size, location, and shape of the detected defects were evaluated by comparing the LUT and micro-CT inspection results. Consequently, the LUT method showed a performance comparable to that of micro-CT for detecting the manufacturing defects of 3D-printed CFRP. Since the LUT is capable of inspecting large scale 3D-printed composites, it will be absolutely advantageous in real world applications.
A New Test of Irony and Indirect Requests Comprehension—The IRRI Test: Validation and Normative Data in French-Speaking Adults
Authors: Cordonier Natacha , Champagne-Lavau Maud , Fossard Marion
Published: May 2021

Objective

Nonliteral language comprehension disorders in individuals with acquired brain injuries (ABI) are frequently reported in the literature but rarely assessed in clinical settings. A major reason is the lack of tools available to clinicians. Therefore, the present study aimed to further promote the pragmatic assessment routine by creating a new nonliteral language comprehension tool for ABI individuals: the IRRI test. This tool is intended to be standardized and capable of directing clinicians to cognitive deficits underlying a poor understanding of nonliteral language—context processing, executive functions, and theory of mind.

Method

Three studies were conducted. The first study aimed at constructing the two IRRI test tasks: the irony and indirect requests comprehension tasks. These tasks integrate the cognitive processes within them. The second study aimed at analyzing the tasks’ psychometric qualities in a sample of 33 ABI participants and 33 healthy participants (HC). Preliminary normative data obtained from 102 healthy French-speaking subjects were collected in the third study.

Results

Significant differences in the IRRI test’s performances were observed between the ABI and HC individuals. The indirect requests task demonstrated robust convergent validity and good sensibility to discriminate altered participants among ABI participants. Both IRRI test’s tasks also showed excellent test–retest and inter-rater reliability. The preliminary norms were stratified according to the conditions of interest in relation to the cognitive mechanisms underlying the understanding of nonliteral language.

Conclusions

The IRRI test is a promising new standardized test of nonliteral language comprehension, which contributes to identifying cognitive-pragmatic profiles to guide therapy.
Context-dependent group size: effects of population density, habitat, and season
Authors: Webber Quinn M R , Vander Wal Eric
Published: May 2021

Group size can vary in relation to population density, habitat, and season. Habitat and season may also interact with population density and affect group size through varying foraging benefits of social aggregation in different ecological contexts. We tested the hypothesis that group size varies across ecological contexts, including population density, habitat type, and season, for woodland caribou (Rangifer tarandus) in ten herds over 25 years in Newfoundland, Canada. We predicted that group size would increase as a function of population density. Based on the foraging benefits of social aggregation, we predicted larger groups as habitat openness increased because open areas tend to have higher quality foraging resources. We predicted larger groups during winter when foraging resources are covered in snow because caribou and other social animals exploit social information about the location of foraging resources. In contrast to our prediction, group size decreased as a function of population density. In support of our prediction, group size was larger in winter than calving and summer, and we found that group size increased with habitat openness in some, but not all, cases. Patterns of animal grouping are context-dependent and the additive effect of different ecological contexts on variation in group size informs our understanding of the implicit trade-offs between competition, predation risk, and profitability of forage.
Resting-State Network Alterations Differ between Alzheimer’s Disease Atrophy Subtypes
Authors: Rauchmann Boris-Stephan , Ersoezlue Ersin , Stoecklein Sophia , Keeser Daniel , Brosseron Frederic , Buerger Katharina , Dechent Peter , Dobisch Laura , Ertl-Wagner Birgit , Fliessbach Klaus , Haynes John Dylan , Heneka Michael T , Incesoy Enise I , Janowitz Daniel , Kilimann Ingo , Laske Christoph , Metzger Coraline D , Munk Matthias H , Peters Oliver , Priller Josef , Ramirez Alfredo , Roeske Sandra , Roy Nina , Scheffler Klaus , Schneider Anja , Spottke Annika , Spruth Eike Jakob , Teipel Stefan , Tscheuschler Maike , Vukovich Ruth , Wagner Michael , Wiltfang Jens , Yakupov Renat , Duezel Emrah , Jessen Frank , Perneczky Robert ,   for the DELCODE study group and the Alzheimer's Disease Neuroimaging Initiative (ADNI)
Published: May 2021

Several Alzheimer’s disease (AD) atrophy subtypes were identified, but their brain network properties are unclear. We analyzed data from two independent datasets, including 166 participants (103 AD/63 controls) from the DZNE-longitudinal cognitive impairment and dementia study and 151 participants (121 AD/30 controls) from the AD neuroimaging initiative cohorts, aiming to identify differences between AD atrophy subtypes in resting-state functional magnetic resonance imaging intra-network connectivity (INC) and global and nodal network properties. Using a data-driven clustering approach, we identified four AD atrophy subtypes with differences in functional connectivity, accompanied by clinical and biomarker alterations, including a medio-temporal-predominant (S-MT), a limbic-predominant (S-L), a diffuse (S-D), and a mild-atrophy (S-MA) subtype. S-MT and S-D showed INC reduction in the default mode, dorsal attention, visual and limbic network, and a pronounced reduction of “global efficiency” and decrease of the “clustering coefficient” in parietal and temporal lobes. Despite severe atrophy in limbic areas, the S-L exhibited only marginal global network but substantial nodal network failure. S-MA, in contrast, showed limited impairment in clinical and cognitive scores but pronounced global network failure. Our results contribute toward a better understanding of heterogeneity in AD with the detection of distinct differences in functional connectivity networks accompanied by CSF biomarker and cognitive differences in AD subtypes.
White and Gray Matter Abnormalities in Australian Footballers With a History of Sports-Related Concussion: An MRI Study
Authors: Major Brendan , Symons Georgia F , Sinclair Ben , O’Brien William T , Costello Daniel , Wright David K , Clough Meaghan , Mutimer Steven , Sun Mujun , Yamakawa Glenn R , Brady Rhys D , O’Sullivan Michael J , Mychasiuk Richelle , McDonald Stuart J , O’Brien Terence J , Law Meng , Kolbe Scott , Shultz Sandy R
Published: May 2021

Sports-related concussion (SRC) is a form of mild traumatic brain injury that has been linked to long-term neurological abnormalities. Australian rules football is a collision sport with wide national participation and is growing in popularity worldwide. However, the chronic neurological consequences of SRC in Australian footballers remain poorly understood. This study investigated the presence of brain abnormalities in Australian footballers with a history of sports-related concussion (HoC) using multimodal MRI. Male Australian footballers with HoC (n = 26), as well as noncollision sport athletes with no HoC (n = 27), were recruited to the study. None of the footballers had sustained a concussion in the preceding 6 months, and all players were asymptomatic. Data were acquired using a 3T MRI scanner. White matter integrity was assessed using diffusion tensor imaging. Cortical thickness, subcortical volumes, and cavum septum pellucidum (CSP) were analyzed using structural MRI. Australian footballers had evidence of widespread microstructural white matter damage and cortical thinning. No significant differences were found regarding subcortical volumes or CSP. These novel findings provide evidence of persisting white and gray matter abnormalities in Australian footballers with HoC, and raise concerns related to the long-term neurological health of these athletes.
Sensitivity, Specificity, and Safety of a Novel ESAT6-CFP10 Skin Test for Tuberculosis Infection in China: 2 Randomized, Self-Controlled, Parallel-Group Phase 2b Trials
Authors: Xu Miao , Lu Wei , Li Tao , Li Jingxin , Du Weixin , Wu Qi , Liu Qiao , Yuan Baodong , Lu Jinbiao , Ding Xiaoyan , Li Feng , Liu Min , Chen Baowen , Pu Jiang , Zhang Rongping , Xi Xiuhong , Zhou Rongguang , Mei Zaoxian , Du Ronghui , Tao Lifeng , Martinez Leonardo , Lu Shuihua , Wang Guozhi , Zhu Fengcai
Published: May 2021

Background

Diagnostics to identify tuberculosis infection are limited. We aimed to assess the diagnostic accuracy and safety of ESAT6-CFP10 (EC) skin test for tuberculosis infection in Chinese adults.

Methods

We conducted 2 randomized, parallel-group clinical trials in healthy participants and tuberculosis patients. All participants were tested with the T-SPOT.TB test, then received an EC skin test and tuberculin skin test (TST). The diameter of skin indurations and/or redness at injection sites were measured at different time periods. A bacillus Calmette Guerin (BCG) model was established to assess the diagnosis of tuberculosis infection using an EC skin test.

Results

In total, 777 healthy participants and 96 tuberculosis patients were allocated to receive EC skin test at 1.0 μg/0.1 mL or 0.5 μg/0.1 mL. The area under the curve was 0.95 (95% confidence interval [CI], .91–.97) for the EC skin test at 1.0 μg/0.1 mL at 24–72 hours. Compared with the T-SPOT.TB test, the EC skin test demonstrated similar sensitivity (87.5, 95% CI, 77.8–97.2 vs 86.5, 95% CI, 79.5–93.4) and specificity (98.9, 95% CI, 96.0–99.9 vs 96.1, 95% CI, 93.5–97.8). Among BCG vaccinated participants, the EC skin test had high consistency with the T-SPOT.TB test (96.3, 95% CI, 92.0–100.0). No serious adverse events related to the EC skin test were observed.

Conclusions

The EC skin test demonstrated both high specificity and sensitivity at a dose of 1.0 μg/0.1 mL, comparable to the T-SPOT.TB test. The diagnostic accuracy of the EC skin test was not impacted by BCG vaccination.

Clinical Trials Registration

NCT02389322 and NCT02336542.
Pneumococcal Meningitis in Adults: A Prospective Nationwide Cohort Study Over a 20-year Period
Authors: Koelman Diederik L H , Brouwer Matthijs C , ter Horst Liora , Bijlsma Merijn W , van der Ende Arie , van de Beek Diederik
Published: May 2021

Background

The epidemiology and treatment of pneumococcal meningitis has changed with the implementation of conjugate vaccines and the introduction of adjunctive dexamethasone therapy.

Methods

We analyzed episodes of community-acquired pneumococcal meningitis in adults (≥16 years) in the Netherlands, identified by the National Reference Laboratory for Bacterial Meningitis or treating physician between October 1, 1998, and April 1, 2002, and between January 1, 2006, and July 1, 2018. We studied incidence, pneumococcal serotypes, and clinical features. Predictors for unfavorable outcome (Glasgow Outcome Scale score 1–4) were identified in a multivariable logistic regression model. Two physicians independently categorized causes of death as neurological or systemic.

Results

There were 1816 episodes in 1783 patients. The incidence of 7- and 10−7-valent pneumococcal conjugate vaccine serotypes decreased (from 0.42 to 0.06, P = .001; from 0.12 to 0.03 episodes per 100 000 population per year, P = .014). Incidence of nonvaccine serotypes increased (from 0.45 to 0.68, P = .005). The use of adjunctive treatment with dexamethasone increased and was administered in 85% of patients in 2018. In-hospital death occurred in 363 episodes (20%) and unfavorable outcome in 772 episodes (43%). Delayed cerebral thrombosis occurred in 29 patients (2%), of whom 15 patients (52%) died. Adjunctive dexamethasone therapy was associated with favorable outcome (adjusted odds ratio 2.27, P < .001), individual pneumococcal serotypes were not.

Conclusion

Implementation of conjugate vaccines and adjunctive dexamethasone therapy have changed the incidence and outcome of pneumococcal meningitis in adults over the last two decades. Despite recent advances pneumococcal meningitis remains associated with a residual high rate of mortality and morbidity.
Validation of aortic valve calcium quantification thresholds measured by computed tomography in Asian patients with calcific aortic stenosis
Authors: Guzzetti Ezequiel , Oh Jin Kyung , Shen Mylène , Dweck Marc R , Poh Kian Keong , Abbas Amr E , Mando Ramy , Pressman Gregg S , Brito Daniel , Tastet Lionel , Pawade Tania , Falconi Mariano Luis , de Arenaza Diego Perez , Kong William , Tay Edgar , Pibarot Philippe , Song Jae-Kwan , Clavel Marie-Annick
Published: May 2021

Aims

Sex-specific thresholds of aortic valve calcification (AVC) have been proposed and validated in Caucasians. Thus, we aimed to validate their accuracy in Asians.

Methods and results

Patients with calcific aortic stenosis (AS) from seven international centres were included. Exclusion criteria were ≥moderate aortic/mitral regurgitation and bicuspid valve. Optimal AVC and AVC-density sex-specific thresholds for severe AS were obtained in concordant grading and normal flow patients (CG/NF). We included 1263 patients [728 (57%) Asians, 573 (45%) women, 837 (66%) with CG/NF]. Mean gradient was 48 (26–64) mmHg and peak aortic velocity 4.5 (3.4–5.1) m/s. Optimal AVC thresholds were: 2145 Agatston Units (AU) in men and 1301 AU in women for Asians; and 1885 AU in men and 1129 AU in women for Caucasians. Overall, accuracy (% correctly classified) was high and comparable either using optimal or guidelines’ thresholds (2000 AU in men, 1200 AU in women). However, accuracy was lower in Asian women vs. Caucasian women (76–78% vs. 94–95%; P < 0.001). Accuracy of AVC-density (476 AU/cm2 in men and 292 AU/cm2 in women) was comparable to absolute AVC in Caucasians (91% vs. 91%, respectively, P = 0.74), but higher than absolute AVC in Asians (87% vs. 81%, P < 0.001). There was no interaction between AVC/AVC-density and ethnicity (all P > 0.41) with regards to AS haemodynamic severity.

Conclusion

AVC thresholds defining severe AS are comparable in Asian and Caucasian populations, and similar to those proposed in the guidelines. However, accuracy of AVC to identify severe AS in Asians (especially women) is sub-optimal. Therefore, the use of AVC-density is preferable in Asians.
Use of quality assessment tools within systematic reviews in orthodontics during the last decade: looking for a threshold?
Authors: Mikelis Filippos , Koletsi Despina
Published: May 2021

Objective

To record the prevalence and extent of use of quality assessment/ risk of bias tools in orthodontic systematic reviews and to identify whether systematic reviews authors stipulated a threshold during the evaluation process of the primary studies included in systematic reviews, published across the previous decade and until now. Associations with publication characteristics including the journal of publication, year, the inclusion of a meta-analysis, design of primary studies and others, were sought.

Materials and Methods

Electronic search within 6 orthodontic journals and the Cochrane Database of Systematic Reviews was conducted to identify relevant systematic reviews from 1 January 2010 and 31 December 2020. The outcomes of interest pertained to the use, type and extent of quality appraisal/ risk of bias tools utilized as a standard process within the systematic reviews, and also whether a threshold had been stipulated by the systematic reviews authors. Predictor variables included journal, year of publication, geographic region, number of authors, involvement of a methodologist, type of systematic reviews, inclusion of meta-analysis, type/design of primary studies.

Results

A total of 262 systematic reviews were eligible for inclusion, with 41 quality appraisal/ risk of bias sets of tools being described either jointly or in isolation. One-third of the systematic reviews of the present sample (88/262; 33.6%) included a threshold, while this was mostly represented by the stipulation of sensitivity analyses in this respect (64/88; 72.8%). Journal of publication (non-Cochrane systematic reviews versus Cochrane systematic reviews: adjusted odds ratio, OR: 0.04, 95%CI: 0.01, 0.16; P < 0.001) and inclusion of a meta-analysis (adjusted OR: 8.76; 95%CI: 4.18, 18.37; P < 0.001), were identified as significant predictors for preplanning of thresholds.

Conclusions and implications

Quality assessment tools for primary studies are largely used and varied in orthodontic systematic reviews, while a threshold-level has been stipulated in only one third. Additional efforts should be endorsed by the scientific community, to embrace more straightforward adoption of the most rigorous reporting guidelines in this respect.
Evidence of a double anaerobic threshold in healthy subjects
Authors: Rovai Sara , Magini Alessandra , Cittar Marco , Masè Marco , Carriere Cosimo , Contini Mauro , Vignati Carlo , Sinagra Gianfranco , Agostoni Piergiuseppe
Published: May 2021

Aims

The anaerobic threshold (AT) is an important cardiopulmonary exercise test (CPET) parameter both in healthy and in patients. It is normally determined with three approaches: V-slope method, ventilatory equivalent method, and end-tidal method. The finding of different AT values with these methods is only anecdotic. We defined the presence of a double threshold (DT) when a ΔVO2 > 15 mL/min was observed between the V-slope method (met AT) and the other two methods (vent AT). The aim was to identify whether there is a DT in healthy subjects.

Methods and results

We retrospectively analysed 476 healthy subjects who performed CPET in our laboratory between 2009 and 2018. We identified 51 subjects with a DT (11% of cases). Cardiopulmonary exercise test data at rest and during the exercise were not different in subjects with DT compared to those without. Met AT always preceded vent AT. Compared to subjects without DT, those with DT showed at met AT lower carbon dioxide output (VCO2), end-tidal carbon dioxide tension (PetCO2) and respiratory exchange ratio (RER), and higher ventilatory equivalent for carbon dioxide (VE/VCO2). Compared to met AT, vent AT showed a higher oxygen uptake (VO2), VCO2, ventilation, respiratory rate, RER, work rate, and PetCO2 but a lower VE/VCO2 and end-tidal oxygen tension. Finally, subjects with DT showed a higher VO2 increase during the isocapnic buffering period.

Conclusion

Double threshold was present in healthy subjects. The presence of DT does not influence peak exercise performance, but it is associated with a delayed before acidosis-induced hyperventilation.
New genomic resources and comparative analyses reveal differences in floral gene expression in selfing and outcrossingCollinsiasister species
Authors: Frazee Lauren J , Rifkin Joanna , Maheepala Dinusha C , Grant Alannie-Grace , Wright Stephen , Kalisz Susan , Litt Amy , Spigler Rachel
Published: May 2021

The evolutionary transition from outcross- to self-fertilization is one of the most common in angiosperms and is often associated with a parallel shift in floral morphological and developmental traits, such as reduced flower size and pollen to ovule ratios, known as the “selfing syndrome.” How these convergent phenotypes arise, the extent to which they are shaped by selection, and the nature of their underlying genetic basis are unsettled questions in evolutionary biology. The genus Collinsia (Plantaginaceae) includes seven independent transitions from outcrossing or mixed mating to high selfing rates accompanied by selfing syndrome traits. Accordingly, Collinsia represents an ideal system for investigating this parallelism, but requires genomic resource development. We present a high quality de novo genome assembly for the highly selfing species Collinsia rattanii. To begin addressing the basis of selfing syndrome developmental shifts, we evaluate and contrast patterns of gene expression from floral transcriptomes across three stages of bud development for C. rattanii and its outcrossing sister species Collinsia linearis. Relative to C. linearis, total gene expression is less variable among individuals and bud stages in C. rattanii. In addition, there is a common pattern among differentially expressed genes: lower expression levels that are more constant across bud development in C. rattanii relative to C. linearis. Transcriptional regulation of enzymes involved in pollen formation specifically in early bud development may influence floral traits that distinguish selfing and outcrossing Collinsia species through pleiotropic functions. Future work will include additional Collinsia outcrossing-selfing species pairs to identify genomic signatures of parallel evolution.
Investigating Older Adults’ Willingness to Invest Time to Acquire Technology Skills Using a Discounting Approach
Authors: Sharit Joseph , Moxley Jerad H , Czaja Sara J
Published: May 2021

Background and Objectives

Delay discounting is a common behavioral phenomenon that can influence decision making. A person with a higher discounting rate (DR) will have a stronger preference for smaller, more immediate rewards over larger, delayed rewards than will a person with a lower DR. This study used a novel approach to investigate, among a diverse sample of older adults, discounting of the time people were willing to invest to acquire technology skills across various technologies.

Research Design and Methods

One hundred and eighty-seven male and female adults 65–92 years of age participated in the study and were given presentations on 5 different technologies spanning domains that included transportation, leisure, health, and new learning. A measure of discounting was computed based on participants’ assessments of how much additional time they would be willing to spend to acquire increased skill levels on each of the technologies and their ratings of importance of attaining those skill levels. Measures of participants’ perceived value of the technologies, technology readiness, and self-assessed cognitive abilities were also collected.

Results

The findings indicated a significant and robust effect of lower DRs with increasing age. Higher perceived value of the technologies and higher levels of positive technology readiness predicted willingness to invest more time to learn the technologies, whereas self-assessments of cognitive abilities predicted the levels of technology skills that participants desired on the 5 technologies.

Discussion and Implications

Our findings demonstrate that for realistic decision-making scenarios related to the acquisition of technology skills, DRs decrease with increasing age, even within an older adult cohort, and that discounting is related to the perceived value of the technology. The findings also have important implications for the design and marketing of technology products for older consumers.
Efficient extended-search space full-waveform inversion with unknown source signatures
Authors: Aghamiry H S , Mamfoumbi-Ozoumet F W , Gholami A , Operto S
Published: May 2021

Full waveform inversion (FWI) requires an accurate estimation of source signatures. Due to the coupling between the source signatures and the subsurface model, small errors in the former can translate into large errors in the latter. When direct methods are used to solve the forward problem, classical frequency-domain FWI efficiently processes multiple sources for source signature and wavefield estimations once a single lower–upper (LU) decomposition of the wave-equation operator has been performed. However, this efficient FWI formulation is based on the exact solution of the wave equation and hence is highly sensitive to the inaccuracy of the velocity model due to the cycle skipping pathology. Recent extended-space FWI variants tackle this sensitivity issue through a relaxation of the wave equation combined with data assimilation, allowing the wavefields to closely match the data from the first inversion iteration. Then, the subsurface parameters are updated by minimizing the wave-equation violations. When the wavefields and the source signatures are jointly estimated with this approach, the extended wave equation operator becomes source dependent, hence making direct methods and, to a lesser extent, block iterative methods ineffective. In this paper, we propose a simple method to bypass this issue and estimate source signatures efficiently during extended FWI. The proposed method replaces each source with a blended source during each data-assimilated wavefield reconstruction to make the extended wave equation operator source independent. Besides computational efficiency, the additional degrees of freedom introduced by spatially distributing the sources allows for a better signature estimation at the physical location when the velocity model is rough. We implement the source signature estimation with a variable projection method in the recently proposed iteratively refined wavefield reconstruction inversion (IR-WRI) method. Numerical tests on the Marmousi II and 2004 BP salt synthetic models confirm the efficiency and the robustness against velocity model errors of the new method compared to the case where source signatures are known.
Estimation of micro-earthquake source locations based on full adjoint P and S wavefield imaging
Authors: Duan Chenglong , Lumley David , Zhu Hejun
Published: May 2021

Locating micro-earthquakes with high resolution and accuracy is a challenge for traveltime inversion, which has uncertainty on the order of a Fresnel zone (many wavelengths). We develop a wave-equation imaging method to increase resolution and reduce location errors to less than a wavelength, but requires very densely deployed receiver arrays with wide aperture and considerable computational cost. Instead of using acoustic data or direct P wave arrivals only, we use elastic multicomponent data and present a new method that uses the full P and S adjoint wavefields to image the microseismic source locations. We separate the P and S waves from the data, and extrapolate the P and S wavefields of each receiver subarray by solving the P and S adjoint wave equations in parallel. We formulate three source imaging conditions by multiplying over subarrays the adjoint P wavefield (IP), S wavefield (IS) and cross-correlated P and S wavefields (IPS). We perform numerical experiments on the highly realistic SEG SEAM4D reservoir model using surface acquisition array geometries. Results for 2-D and 3-D microseismic source estimations show clean images without noisy artefacts at shallow depths. In particular, IPS provides the highest resolution source location image, while IP is limited by the P wavelength and IS is influenced by small coda artefacts. The major-axis alignment and resolution of the source location image are determined by the hypocentral location with respect to the receiver array and illumination-angle coverage, respectively. We discuss the impacts of S-wave attenuation and frequency bandwidth on the source location images. Noise tests indicate that the imaging results are relatively insensitive to ambient noise, as is observed for the surface monitoring data. Using smoothed velocity models, the imaging results are similar to the results using the true realistically heterogeneous velocity model. The 90 per cent confidence ellipse of the source location due to Gaussian-distributed velocity errors shows a larger depth error as the source becomes deeper, while the horizontal error does not change as much.
Transmitral resection of left ventricular lipoma by right mini-thoracotomy using a rolled up flexible ruler
Authors: Kim Yun Seok , Kim Jin Young , Shin Hyeong Chan
Published: May 2021

Left ventricular lipoma is a rare intracardiac tumour that is usually resected through sternotomy to effectively explore the left ventricular cavity. We introduce a simple technique to expose the left ventricular cavity and resect the intraventricular lipoma using a rolled up flexible ruler through right mini-thoracotomy. Imaging studies and gross and microscopic photography of intraventricular lipoma are presented in this report.
Cost of Illness Due to Severe Enteric Fever in India
Authors: Kumar Dilesh , Sharma Atul , Rana Saroj Kumar , Prinja Shankar , Ramanujam Karthikeyan , Karthikeyan Arun S , Raju Reshma , Njarekkattuvalappil Swathi Krishna , Premkumar Prasanna S , Chauhan Akashdeep Singh , Mohan Venkata Raghava , Ebenezer Sheena Evelyn , Thomas Mathew Santosh , Gupta Madhu , Singh Ashita , Jinka Dasaratha Ramaiah , Thankaraj Shajin , Koshy Roshine Mary , Dhas Sankhro Christina , Kapil Arti , Shastri Jayanthi , Saigal Karnika , Perumal Sulochana Putli Bai , Nagaraj Savitha , Anandan Shalini , Thomas Maria , Ray Pallab , John Jacob , Kang Gagandeep
Published: May 2021

Background

Lack of robust data on economic burden due to enteric fever in India has made decision making on typhoid vaccination a challenge. Surveillance for Enteric Fever network was established to address gaps in typhoid disease and economic burden.

Methods

Patients hospitalized with blood culture-confirmed enteric fever and nontraumatic ileal perforation were identified at 14 hospitals. These sites represent urban referral hospitals (tier 3) and smaller hospitals in urban slums, remote rural, and tribal settings (tier 2). Cost of illness and productivity loss data from onset to 28 days after discharge from hospital were collected using a structured questionnaire. The direct and indirect costs of an illness episode were analyzed by type of setting.

Results

In total, 274 patients from tier 2 surveillance, 891 patients from tier 3 surveillance, and 110 ileal perforation patients provided the cost of illness data. The mean direct cost of severe enteric fever was US$119.1 (95% confidence interval [CI], US$85.8–152.4) in tier 2 and US$405.7 (95% CI, 366.9–444.4) in tier 3; 16.9% of patients in tier 3 experienced catastrophic expenditure.

Conclusions

The cost of treating enteric fever is considerable and likely to increase with emerging antimicrobial resistance. Equitable preventive strategies are urgently needed.
Assessment of adherence to pneumonia guidelines and its determinants in an ambulatory care clinic in Ghana: findings and implications for the future
Authors: Sefah Israel Abebrese , Essah Darius Obeng , Kurdi Amanj , Sneddon Jacqueline , Alalbila Thelma Mpoku , Kordorwu Hope , Godman Brian
Published: May 2021

Background

Adherence to local standard guidelines is seen as a pragmatic way to measure and improve the quality of future prescribing in ambulatory care to reduce morbidity, mortality and healthcare costs.

Objectives

To evaluate adherence to the Ghana Standard Treatment Guidelines (STGs) for the empirical antibiotic treatment of ambulatory care patients with community-acquired pneumonia (CAP) in a region in Ghana and factors associated with it.

Methods

A cross-sectional survey was conducted using a checklist to collect data from the hospital electronic database, which included sociodemographic details, payment type and clinical information of all ambulatory patients attending Keta Municipal Hospital, diagnosed and managed for CAP from September 2018 to January 2019. Prescriptions were assessed for adherence to the Ghana STG based on choice of antibiotics. A χ2 test and multiple logistic regression were subsequently conducted.

Results

A total of 1929 patient records with diagnosis of CAP within the study period at the ambulatory clinic were identified. The overall rate of adherence to the Ghana STG was 32.50% (n = 627). From the patient records collected, 62.50% were female, 41.84% were children (0–12 years), and 97.15% had a valid national health insurance status. Adherence was associated with the duration of antibiotic prescribing, number of additional antibiotics prescribed and some patients’ clinical characteristics.

Conclusions

The rate of adherence to Ghana STG among the study population was low. Efforts must be made to train and encourage prescribers to follow empirical guidelines to reduce inappropriate selection of antibiotics in the ambulatory care settings.
Management of Pediatric Pavement Burns
Authors: Saquib Syed , Carroll Joseph , Flores Carmen , Chestovich Paul
Published: May 2021

Pavement burns are common in a dry high heat climate. This study reviews the etiology, management, and outcome pavement burns in children. All patients age <18 who sustained contact burns from hot pavement from January 1, 2014 to December 31, 2019 were reviewed for mechanism, medical history, treatment course, and outcome. The high ambient temperature on each date and zip code of each injury were extracted from Weather Underground (www.wunderground.com). In this study, 45 patients met criteria and were reviewed 27 patients (60%) were male. Average age was 3.29 years (SD 0.69), made up two discrete age groups: age 3 years and under (n = 40, 89%) and older patients 14 years of age and up (n = 5, 11%). Thirty-eight patients (84%) had no known medical history. All had second-degree burns and one patient (2%) also had third-degree burns. Mean TBSA was 2.5% (SD 1.4%, range 0.75%–5.5%). Burn etiology included 31 patients (69%) who were walking barefoot on pavement, six (13%) who fell onto pavement, one (2%) seizure, and other/unknown etiology for the remaining seven patients (16%). Thirty patients (67%) had injuries on the plantar aspect of the bilateral feet, two (4%) to bilateral palms of hands, four (9%) to other parts of upper extremities, and 10 (22%) to other parts of lower extremities. Thirty-four patients (76%) were managed without any hospitalization. Those that were hospitalized had an average length of stay of 2.72 days (range 1–9 days). All burns were managed nonoperatively with topical therapy alone. Thirty-four patients (76%) were managed initially with silver sulfadiazene alone and six (13%) with bacitracin alone. Aquacel dressing was utilized in 10 patients at a follow-up visit (22%). Three patients (6.7%) were treated with collagenase enzyme therapy at some point in their care. One patient developed a superficial infection requiring oral antibiotic therapy. There were no mortalities in this group. High ambient temperature on date and location of each injury was 102.1°F (SD 5.4°F, range 89–111°F). Of the 30 patients that continued to follow up in clinic the average time to the burn being 95% healed was 10.50 days (SD 8.97 days, range 2–40 days). Pavement burns in children are partial thickness and are safely managed with topical therapy alone with good outcomes. Patients age 3 and under are at high risk.