bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Study on the Propagation Characteristics of Hydraulic Fracture in Clayey-Silt Sediments
Authors: Lu Cheng , Qin Xuwen , Mao Wenjing , Ma Chao , Geng Lantao , Yu Lu , Bian Hang , Meng Fanle , Qi Rongrong
Published: August 2021

The low permeability of clayey-silt hydrate reservoirs in the South China Sea affects the thermal and pressure conductivity of the reservoir, which is difficult to spread to the far end of the wellbore and achieve commercial gas production. In this respect, enhancing the permeability to assist depressurization is necessary. Hydraulic fracturing is a promising reservoir stimulation method for gas hydrate reservoirs. Up to now, majorities of research focus on the fracability of hydrate-bearing sandy sediments, but the studies rarely involved fracture propagation characteristics of clayey-silt sediments in the hydrate dissociation area. In this paper, three sets of hydraulic fracturing experiments under different confining pressure were carried out using the clayey-silt sediments in the Shenhu Area. Computed tomographic (CT) images indicated that clayey-silt sediments could be artificially fractured, and the fracturing fluid could induce tensile fractures and local shear fractures. A multimorphological fracture zone occurred near the borehole. Furthermore, the greater the confining pressure imposed, the greater the breakdown pressure was, and the microfracture arose more easily. The fractures at the top were generally wider than those at the bottom with the same confining pressure. The experimental results could reveal the fracture initiation and propagation mechanism of clayey-silt sediments and provide theoretical support for hydraulic fracture in the hydrate dissociation area.
Variation Law of Infrared Radiation Temperature of Unloading Fracture of Composite Coal-Rock
Authors: Li Xin , Wang Xue , Yang Zhen , Li Hao , Li Yan , Sun Weiman
Published: August 2021

For composite mining coal-rock dynamic disaster, combining the theory of thermodynamics, damage mechanics, and other disciplines, the thermodynamic coupling mathematical model of composite coal-rock under an unloading condition is deduced, and the simulation model of composite coal-rock is established for numerical simulation. And the variation law of thermal infrared radiation under triaxial loading and unloading of composite coal-rock is analyzed and verified by experiments. The results show the following findings: (1) The distribution of thermal infrared radiation temperature of composite coal-rock is different in different stages of stress. The overall temperature of the temperature field is lower than the initial temperature field in the three-dimensional stress loading stage and the stage of stress-keeping pressure, but the internal temperature of the coal body is the highest. In the first stage of “loading and unloading,” the temperature of a coal seam increases slightly, and the temperature of other parts of the rock layer increases except for the circular low-temperature zone. In the second stage of “loading and unloading,” an alternating zone of high and low temperatures appears in the rock mass, and the temperature field is enhanced, among which the temperature field reaches the strongest after unloading the confining pressure. After jumping over the maximum stress, the temperature field decreases as a whole at the instability and rupture stage. (2) The variation of surface average thermal infrared radiation temperature (

T

ave

) of composite coal-rock can be divided into the initial fluctuation stage, the linear heating stage, the local decline stage, the temperature sudden increase stage, and the fracture decline stage. At three different unloading rates of 0.003 MPa/s, 0.03 MPa/s, and 0.05 MPa/s, the

T

ave

of coal body, floor rock, and roof rock reach the maximum before composite coal-rock instability and fracture, and the temperature change of the coal body is the most obvious. (3) Under different confining pressure unloading rates, the

T

ave

of roof rock, coal body, and floor rock shows a strong linear relationship with stress after linear fitting. And the correlation between simulation and experimental results after fitting is above 0.89. The larger the confining pressure unloading rate is, the shorter the peak time of

T

ave

arrives, and the larger the peak value. The comparison between the experimental results and the simulation analysis shows that the two results are consistent, and the research results can provide a theoretical basis for the prevention and control of dynamic disasters in coal and rock mining.
Investigation of the Effect of Polycarbonate Rate on Mechanical Properties of Polybutylene Terephthalate/Polycarbonate Blends
Authors: Tran Ngoc-Thien , Pham Nga Thi-Hong
Published: August 2021

Polybutylene terephthalate (PBT) is a brittle polymer with the disadvantage of low impact toughness, so it is not easy to meet the requirements of both high tensile strength, flexural strength, and high impact strength. In this study, PBT/polycarbonate (PC) blends at different ratios of 95/5, 90/10, 85/15, and 80/20 are investigated. Tensile strength, flexural strength, and unnotched Izod impact strength are studied according to the ASTM D638, ASTM D790, and ASTM D256 standards. The results show that tensile strength, which increased with increasing PC content, is 53.00, 62.34, 60.59, 62.98, and 64.46 MPa for 0, 5, 10, 15, and 20% PC samples. Flexural strength and elastic flexural testing of PBT/PC blends are higher than neat PBT. In addition, the unnotched Izod impact strength of PBT/PC is also higher than PBT. However, when PC content increases, impact strength tends to decrease. Impact strength is 44.82, 80.46, 68.82, 50.45, and 48.05 kJ/m2 corresponds to 0, 5, 10, 15, and 20% PC, in which 5% PC sample is twice as high as the impact strength of PBT. Microstructure of the blends has shown that PC has become dispersed phase in PBT matrix. The size and quantity of dispersed PC particles increase with increasing PC rate in the blend. Thus, when adding PC, PBT/PC all meet the requirements of high tensile strength, flexural strength, and high impact strength. The PBT/5% PC model gives the highest impact strength while still ensuring durability, which potential application for making car door handles.
Experimental Study of Three‐Dimensional Propagation of Crack in Transparent Rock Mass
Authors: Zhu Zhende , Tian Yuan , Liu Xinyu
Published: August 2021

Three‐dimensional crack propagation in a rock mass was investigated using a specifically designed material with good transparency and elastoplasticity. The material has properties that are similar to those of the nature sandstone. Hydromechanical tests were conducted to simulate pore pressure in the paper to study the influence of the angle of the primary crack and the water pressure on the mechanical stability of the rock mass. The results indicated that the water pressure accelerated the crack propagation and the failure of the samples. The influence of water pressure on initiation crack strength was not significant but had a significant impact on the peak strength. With the increase in water pressure, the crack initiation strength, penetration strength, and peak strength all decrease in varying degrees. The penetration strength did not only depend on the pore pressure but also exhibited high sensitivity to the inclination angle of the primary crack. The extended finite element method is used to simulate hydraulic fracturing. The simulation results show that the stress near the tip exhibited a cycle of energy accumulation‐crack expansion‐stress relaxation as the crack expanded, and this finding was consistent with Griffith’s energy theory.
Injection Rate-Dependent Deflecting Propagation Rule of Hydraulic Fracture: Insights from the Rate-Dependent Fracture Process Zone of Mixed-Mode (I-II) Fracturing
Authors: Xing Yuekun , Huang Bingxiang
Published: August 2021

Mixed-mode (I-II) fracturing is a prominent mechanical characteristic of hydraulic fracture (HF) deflecting propagation. At present, understanding the effect of injection rates on HF deflecting propagation remains challenging and restricts the control of HF deflecting propagation bearing tensile and shear stresses with fluid injection rates. Our recently published experimental results show that the fracture process zone (FPZ) length of mixed-mode (I-II) fractures in rock-like materials increases with the rising quasistatic loading rate. Both the deformation in FPZ and the generation of real fracture surfaces are tensile. On this basis, the rate-dependent mixed-mode (I-II) cohesive fracture model was proposed under quasistatic loading, and a couple of theoretical outcomes were obtained. Under different injection rates, the deflecting HF propagates step-by-step under mixed-mode (I-II) fracturing, and the HF extension path is supposed to be straight in each step. With the increment of injection rate, the increased (tensile) FPZ length is the stable propagation distance of deflecting HF in each step and besides deteriorates the fracture resistance discontinuity of FPZ developing to be a real tensile fracture. Thus, the mixed-mode (I-II) fracture tends to propagate unstably driven by kinetic energy once FPZ develops completely under fast loading. Moreover, two injection rate-dependent (IRD) HF deflecting propagation modes were determined, i.e., the step-by-step stable-propagation and step-by-step unstable propagation modes. HF deflection occurs in the step alternation of fracture propagation. With the increasing fluid injection rate, the increased FPZ length and kinetic energy (from fracture resistance discontinuity) extend the stable and unstable HF propagation distance along the initial direction in an extension step, respectively. Therefore, fast fluid injection improves the HF deflecting propagation radius; i.e., it inhibits the HF deflecting propagation or promotes HF extension along the initially designed direction. The injection rate-dependent HF deflecting propagation modes (based on the proposed model) were validated by further processing of published true triaxial physical simulation tests of hydraulic fracturing. The ordinal response of Fiber Bragg grating sensors embedded along the fracture propagation path, and the continuous fluctuant injecting pressures validate the step-by-step propagation of the hydraulic fracture. The test-measured deflecting HF trajectory indicates that high fluid injection rates remarkably increase the HF deflecting radius, which is consistent with the theoretical analysis in this work. The above findings can provide theoretical bases for controlling the HF deflecting propagation in the surrounding rock of mines and oil-gas reservoirs.
Effect of Acid and Alkaline Environment on Dynamic Strength and Porosity Characteristics of Bursting Liability Coal
Authors: Li Lei , Fan Jiangbo , Liu Ningning , Gong Shuang , Yang Daming
Published: August 2021

In order to investigate the influence of acid and alkaline environment on dynamic strength and porosity characteristics of bursting liability coal, scanning electron microscopy (SEM) and X‐ray diffraction (XRD) analysis were used to compare the microstructures of coal with different bursting liabilities. A split Hopkinson bar (SHPB) was used to test the dynamic compressive strength and tensile strength of coal samples with different bursting liabilities. The results show that the surface micromorphology and structure characteristics of coal samples with different bursting liabilities are representatives, which can be used as an auxiliary basis to determine the bursting liability of coal seam. The microstructure of coal with strong bursting liability is characterized by mylonitic, fragmentary, and brecciated structure, and the microstructure is diverse and complex. However, the microstructure of no bursting liability coal is single and uniform. Coal with strong bursting liability shows tensile, compressive, and shear cracks produced by tectonic action, and the distribution of cracks is complicated. The development of fissures is greatly affected by the degree of coal metamorphism, organic components, minerals, and other factors. Under acidic and alkaline environments, the decrease amplitude of tensile strength of coal is obviously larger than that in neutral solution, which indicates that under the action of acid‐based solution soaking, the easily soluble minerals in coal react with hydrogen ions and hydroxyl ions in solution obviously. Porosity increment in acidic environment is much larger than that in alkaline and neutral environments. The strong bursting liability coal is more sensitive to acidic environment, while the no bursting liability coal is more sensitive to alkaline environment.
Dynamic Control Subarea Division Based on Node Importance Evaluating
Authors: Tian Xiujuan , Liang Chunyan , Feng Tianjun
Published: August 2021

In order to optimize the existing control subarea division methods, a new dynamic subarea division method based on node importance evaluating is proposed for regional coordinated control. Firstly, considering the characteristics of road network and traffic flow between adjacent intersections, correlation degree model is established by calculating the correlation coefficients of traffic flow, signal cycle, and traffic state. Then, road traffic network is abstracted into a network topology structure graph. From the global perspective of the road network, intersection position information and the importance contribution between adjacent intersections are taken into account, and the correlation degrees between adjacent intersections are taken as the edge weights to construct intersection importance evaluation matrix. Finally, an actual road network is selected, and an improved Newman algorithm is employed to verify and analyze the method proposed in this paper. Results show that, compared with other methods, the control subarea division result of the new proposed method is more elaborate and more in line with the actual traffic flow characteristics. Moreover, dynamic subarea division can be realized according to the traffic characteristics of different periods, which can provide a good basis for the formulation of the signal control schemes in the next stage.
Food Safety Risk Communication between the Food Regulator and Consumer in China: An Evolutionary Game Perspective
Authors: Zhu Ying , Chu May , Wen Xiaowei , Wang Yiqin
Published: August 2021

Food safety risk communication has attracted widespread attention in China. The government is the leader in food risk communication. It has even more impact on consumers’ willingness to communicate food risk. Thus, this paper constructs a risk communication game model composed of the central government, local government, and consumers under food safety regulatory agencies in China. Based on the evolutionary game theory, we achieved the evolutionary stable equilibrium points under complying different constraint conditions by solving the replicator dynamic equations of parties in the dynamic system. In the end, some numerical examples have been displayed to simulate the agents’ choices. The results show that penalty cost, governance intensity, communication cost, and reputation of the government have an essential impact on consumers’ enthusiasm for food safety risk communication decision‐making behavior. Furthermore, the choice of food safety risk communication strategies is performed with a dynamic process, which is constantly adjusted and optimized. The evolutionary game system can converge on an ideal state under certain conditions. Moreover, this study proposes suggestions and measures conducive to the tripartite game, which can offer valuable guidance on food risk communication practice and improve government efficiency in China. This research can provide the evolutionary mechanism and broaden our understanding of the relationship between food safety risk governance and food risk communication strategies.
The Design of A Novel Sparse Array Using Two Uniform Linear Arrays considering Mutual Coupling
Authors: Xu Haiyun , Cui Weijia , Mei Fengtong , Ba Bin , Jian Chunxiao
Published: August 2021

The sparse arrays using two uniform linear arrays have attracted considerable interest due to the capability of giving analytical expression of sensor location and owning robust direction‐of‐arrival (DOA) facing strong mutual coupling and sensor failure. In order to achieve the maximum consecutive virtual uniform linear array in difference coarray, in this paper, a design method of a novel sparse array using two uniform linear arrays (NSA‐U2) is proposed. We first analyze the relationship between the values of displacement of two subarrays and difference coarray, and then we give the analytical expressions of the displacement and the number of consecutive lags. By discussing the selection of number of subarray sensors, the design of NSA‐U2 is completed. Moreover, through choosing a proper compressed interelement spacing, NSA‐U2 can be robust to mutual coupling effect. Numerical experiments prove the effectiveness and favorable performance of DOA estimation with mutual coupling.
Electromechanical Performance Analysis of the Hybrid Piezoelectric‐Electromagnetic Energy Harvester under Rotary Magnetic Plucking Excitation
Authors: Wang Hongyan , Hu Jiarui , Sun Gang , Zou Liying
Published: August 2021

This paper presents an analysis of the hybrid piezoelectric‐electromagnetic energy harvester (P‐EMEH) driven by contactless rotary magnetic plucking. A lumped‐parameter model of the hybrid P‐EMEH is developed, and the model parameters are determined from the finite element analysis (FEA) method. A parametric study is conducted to investigate the effects of driving force parameters, load resistance, and electromechanical coupling strengths (EMCSs) on the maximal displacements and velocities, average power inputs and outputs, and energy efficiencies of the system for indicating the performance of the hybrid P‐EMEH. The results show that the hybrid P‐EMEH can obtain the improved power inputs by reducing the gyration radii of the rotary magnet and shortening the gaps between the two magnets. The structural vibrations can be strongly suppressed owing to the optimal piezoelectric power outputs, which can lead to the occurrence of valleys’ power of the electromagnetic element. At weak coupling, the hybrid P‐EMEH can achieve higher power outputs than the single piezoelectric energy harvester (PEH) and the single electromagnetic energy harvester (EMEH). At strong coupling, the use of the PEH is more advantageous for energy harvesting due to wider power bandwidths at high dimensionless frequencies when compared with the hybrid P‐EMEH. This work provides a fundamental understanding on the effect of load resistance and EMCSs on the dynamic and electrical characteristics of the magnetically plucked hybrid P‐EMEH.
Problems and Countermeasures in the Process of Applying Multimedia Technology in Basketball Teaching
Authors: Yan Bixia
Published: August 2021

Nowadays, there are few researches on using multimedia animation technology to assist basketball tactics teaching and training in college physical education. The research of multimedia animation assisting basketball tactics teaching can help promote the current teaching mode, teaching environment, and teaching methods. From the perspective of the development trend of modern education and the benefits of multimedia technology in physical education teaching, this article demonstrates the inevitability of applying multimedia technology in college basketball teaching and demonstrates the feasibility of implementing multimedia physical education in colleges and universities from the three aspects of multimedia teaching environment, teacher teaching ability analyzes the factors that affect the effect of multimedia‐assisted teaching. Students’ acceptance characteristics of the multimedia environment are obtained. Relevant research results and suggestions on the use of multimedia animation in basketball tactics teaching will be submitted. Research shows the ability and student’s learning ability. It analyzes the effects of multimedia‐assisted teaching in basketball tactics. In this article, at 84% of teachers feel that multimedia‐assisted teaching is better. However, some objective factors restrict teachers’ use of multimedia‐assisted teaching methods. Among them, poor production technology and inconvenient use are the main factors that teachers think affect the application of multimedia‐assisted teaching methods in actual teaching, and these influencing factors are difficult to eliminate in a short time.
Three‐Dimensional Stress Intensity Factor Correction Method Based on Thickness Size Effect
Authors: Zhang Xiaochen , Li Hanwen , Meng Weiying , Zhang Tian , Liu Zhenpeng , Lv Xiao
Published: August 2021

This paper presents the fatigue crack growth test of 7N01 aluminum alloy specimens with different thicknesses under three‐point bending. Moreover, the effect of specimen thickness on the fatigue crack growth life was analyzed. The influence mechanism of the thickness size effect on the stress intensity factor was explored. A three‐dimensional stress intensity factor calculation model based on the thickness size effect was proposed by combining the finite element method and the interaction integral method. The results show that the fatigue crack growth life of 7N01 aluminum alloy decreases with the increase of specimen thickness. The numerical solutions of the stress intensity factor (the proposed model) are higher than the analytical solutions (the traditional formula) in the steady‐state crack growth stage. The difference between numerical solutions and analytical solutions increases with the increase of crack growth length and specimen thickness. Compared with the analytical solutions, the relationship curve between crack length “a” and cycle number “N” from the numerical solutions is closer to the experimental data. This result proves that the proposed calculation model can correct the stress intensity factor with the thickness size effect.
A Randomized Phase II Study of Nivolumab Monotherapy or Nivolumab Combined with Ipilimumab in Patients with Advanced Gastrointestinal Stromal Tumors
Authors: Singh Arun S. , Hecht J. Randolph , Rosen Lee , Wainberg Zev A. , Wang Xiaoyan , Douek Michael , Hagopian Anahis , Andes Rachel , Sauer Lauren , Brackert Sandra R. , Chow Warren , DeMatteo Ronald , Eilber Fritz Christian , Glaspy John A. , Chmielowski Bartosz
Published: August 2021

Purpose:

Most gastrointestinal stromal tumors (GIST) are driven by KIT/PDGFRa mutations. Tyrosine kinase inhibitor benefit is progressively less after imatinib failure. This phase II trial analyzed the efficacy of nivolumab (N) or nivolumab + ipilimumab (N + I) in patients with refractory GIST.

Patients and Methods:

Patients with advanced/metastatic GIST refractory to at least imatinib were randomized 1:1 in a noncomparative, parallel group, unblinded phase II trial of N (240 mg every 2 weeks) or N + I (240 mg every 2 weeks + 1 mg/kg every 6 weeks). The primary endpoint was the objective response rate of N alone or N+I by RECIST 1.1 in the intent-to-treat population.

Results:

A total of 36 patients with a median of 3 (1–6) prior lines of therapies were enrolled. Ten of 19 (52.6%) patients had stable disease (SD) for a clinical benefit rate (CBR) of 52.6% in the N arm and the median progression-free survival (PFS) was 11.7 weeks [95% confidence interval (CI), 7.0–17.4]. In the N+I arm, 1 of 16 (6.7%) patients had a complete response (CR) and 4/16 (25.0%) had SD for a CBR of 31.3% and a median PFS of 8.3 weeks (95% CI, 5.6–22.2). The 4- and 6-month PFS were 42.1% and 26.3%, respectively for N, and 31.3% and 18.8%, respectively for N+I. The most common adverse events (AE) attributed to N and N+I were fatigue: 13.9% and 22.2%, respectively. There were nine total attributable grade 3–4 AEs.

Conclusions:

The primary endpoint of response rate > 15% was not observed for N or N + I. In a heavily pretreated GIST population, responses and long-term disease control with both N and N+I were observed. No new safety signals have been observed.
Association of AXL and PD-L1 Expression with Clinical Outcomes in Patients with Advanced Renal Cell Carcinoma Treated with PD-1 Blockade
Authors: Terry Stéphane , Dalban Cécile , Rioux-Leclercq Nathalie , Adam Julien , Meylan Maxime , Buart Stéphanie , Bougoüin Antoine , Lespagnol Alexandra , Dugay Frédéric , Moreno Irelka Colina , Lacroix Guillaume , Lorens James B. , Gausdal Gro , Fridman Wolf H. , Mami-Chouaib Fathia , Chaput Nathalie , Beuselinck Benoit , Chabaud Sylvie , Barros-Monteiro Janice , Vano Yann , Escudier Bernard , Sautès-Fridman Catherine , Albiges Laurence , Chouaib Salem
Published: August 2021

Purpose:

A minority of patients currently respond to single-agent immune-checkpoint blockade (ICB), and strategies to increase response rates are urgently needed. AXL is a receptor tyrosine kinase commonly associated with drug resistance and poor prognosis in many cancer types, including in clear-cell renal cell carcinoma (ccRCC). Recent experimental cues in breast, pancreatic, and lung cancer models have linked AXL with immune suppression and resistance to antitumor immunity. However, its role in intrinsic and acquired resistance to ICB remains largely unexplored.

Experimental Design:

In this study, tumoral expression of AXL was examined in ccRCC specimens from 316 patients who were metastatic receiving the PD-1 inhibitor nivolumab in the GETUG AFU 26 NIVOREN trial after failure of antiangiogenic therapy. We assessed associations between AXL and patient outcomes following PD-1 blockade, as well as the relationship with various markers, including PD-L1; VEGFA; the immune markers CD3, CD8, CD163, and CD20; and the mutational status of the tumor-suppressor gene von Hippel-Lindau (VHL).

Results:

Our results show that high AXL-expression level in tumor cells is associated with lower response rates and a trend to shorter progression-free survival following anti–PD-1 treatment. AXL expression was strongly associated with tumor–PD-L1 expression, especially in tumors with VHL inactivation. Moreover, patients with tumors displaying concomitant PD-L1 expression and high AXL expression had the worst overall survival.

Conclusions:

Our findings propose AXL as candidate factor of resistance to PD-1 blockade, and provide compelling support for screening both AXL and PD-L1 expression in the management of advanced ccRCC.

See related commentary by Hahn et al., p. 6619
Automated Perfusion-Diffusion Magnetic Resonance Imaging in Childhood Arterial Ischemic Stroke
Authors: Visser Melissa J. , Yang Joseph Yuan-Mou , Calamante Fernando , Kean Michael , Adamson Christopher L. , Sharma Gagan , Anderson Vicki , Campbell Bruce C.V. , Mackay Mark T.
Published: August 2021

Background and Purpose:

Recent studies using automated perfusion imaging software have identified adults most likely to benefit from reperfusion therapies in extended time windows. The time course of penumbral tissue is poorly characterized in childhood arterial ischemic stroke (AIS). We explore the feasibility of using automated perfusion-diffusion imaging software to characterize penumbra in childhood AIS.

Methods:

An observational cohort study of children with acute unilateral AIS presenting to our institution. Diffusion-weighted imaging and dynamic susceptibility contrast perfusion magnetic resonance imaging performed within 72 hours of symptom onset were necessary for inclusion. Perfusion-diffusion mismatch was estimated using RAPID software. Ischemic core was defined as apparent diffusion coefficient <620×10
−6
mm
2
/s and hypoperfusion as Tmax >6 seconds. Favorable mismatch profile was defined as core volume <70 mL, mismatch volume ≥15 mL, and a mismatch ratio ≥1.8.

Results:

Twenty-nine children (median 8 years old, interquartile range, 4.4–14.6) were included (26 unilateral middle cerebral artery and 3 unilateral cerebellar infarcts). Median Pediatric National Institutes of Health Stroke Scale was 4 (interquartile range, 3–11). Most cases had cryptogenic (n=11) or focal cerebral arteriopathy (n=9) causes. Median time-to-imaging =13.7 hours (interquartile range, 7.5–25.3). RAPID detected an ischemic core in 19 (66%) patients. In the remaining cases, the mean apparent diffusion coefficient values were mostly higher than the threshold as the majority of these presentations were delayed (median >21 hours) and infarct volumes were small (<3.5 mL). Overall, 3 children, imaged at 3.75, 11, and 23.5 hours had favorable mismatch profiles.

Conclusions:

This study demonstrates it is feasible to rapidly assess perfusion-diffusion mismatch in childhood AIS using automated software. Favorable mismatch profiles, using adult-based parameters, persisted beyond the standard 4.5 hours window for thrombolysis, suggesting potential therapeutic benefit of RAPID use. Further work is required to determine the utility of perfusion-based imaging to guide clinical decision making, whether adult thresholds require modification in childhood AIS, and to investigate the effect of time-delay and cause on mismatch characteristics.
Dual Antiplatelet Therapy Using Cilostazol With Aspirin or Clopidogrel: Subanalysis of the CSPS.com Trial
Authors: Hoshino Haruhiko , Toyoda Kazunori , Omae Katsuhiro , Ishida Noriyuki , Uchiyama Shinichiro , Kimura Kazumi , Sakai Nobuyuki , Okada Yasushi , Tanaka Kortaro , Origasa Hideki , Naritomi Hiroaki , Houkin Kiyohiro , Yamaguchi Keiji , Isobe Masanori , Minematsu Kazuo , Matsumoto Masayasu , Tominaga Teiji , Tomimoto Hidekazu , Terayama Yasuo , Yasuda Satoshi , Yamaguchi Takenori ,   on behalf of the CSPS.com Trial Investigators
Published: August 2021

Background and Purpose:

Although dual antiplatelet therapy (DAPT) with aspirin and clopidogrel reduces the recurrence of ischemic stroke while significantly increasing the bleeding events compared with monotherapy, the
CSPS.com
trial (Cilostazol Stroke Prevention Study combination) showed that DAPT using cilostazol was more effective without the bleeding risk. In the
CSPS.com
trial, aspirin or clopidogrel was used as the underlying antiplatelet drug. The effectiveness and safety of each combination were examined and clarified.

Methods:

In the
CSPS.com
trial, a multicenter, open-label, randomized controlled study, patients with high-risk, noncardioembolic ischemic stroke 8 to 180 days after onset treated with aspirin or clopidogrel alone at the discretion of the physician in charge were recruited. Patients were randomly assigned to receive either monotherapy or DAPT using cilostazol and followed for 0.5 to 3.5 years. The primary efficacy outcome was first recurrence of ischemic stroke. The safety outcome was severe or life-threatening bleeding. The analysis was based on the underlying antiplatelet agents.

Results:

A total of 763 patients taking aspirin and 1116 taking clopidogrel were included in the intention-to-treat analysis. Although the clopidogrel group had more risk factors than the aspirin group, the primary efficacy outcome and safety outcome did not differ significantly between the 2 groups. In the aspirin group, the primary efficacy outcome and safety outcome did not differ significantly between the DAPT group and the aspirin-monotherapy group. In the clopidogrel group, the primary end point occurred at a rate of 2.31 per 100 patient-years in the DAPT group and 5.19 per 100 patient-years in the clopidogrel-monotherapy group (hazard ratio, 0.447 [95% CI, 0.258–0.774]). Safety outcome did not differ significantly between groups (0.51 per 100 patient-years versus 0.71 per 100 patient-years, respectively; hazard ratio, 0.730 [95% CI, 0.206–2.588]).

Conclusions:

The combination of cilostazol and clopidogrel significantly reduced the recurrence of ischemic stroke without increasing the bleeding risk in noncardioembolic, high-risk patients.

Registration:

URL:
https://www.clinicaltrials.gov
; Unique identifier: NCT01995370. URL:
https://www.umin.ac.jp/ctr/
; Unique identifier: UMIN000012180.
Graspability Modulates the Stronger Neural Signature of Motor Preparation for Real Objects vs. Pictures
Authors: Fairchild Grant T. , Marini Francesco , Snow Jacqueline C.
Published: August 2021

The cognitive and neural bases of visual perception are typically studied using pictures rather than real-world stimuli. Unlike pictures, real objects are actionable solids that can be manipulated with the hands. Recent evidence from human brain imaging suggests that neural responses to real objects differ from responses to pictures; however, little is known about the neural mechanisms that drive these differences. Here, we tested whether brain responses to real objects versus pictures are differentially modulated by the “in-the-moment” graspability of the stimulus. In human dorsal cortex, electroencephalographic responses show a “real object advantage” in the strength and duration of mu (μ) and low beta (β) rhythm desynchronization—well-known neural signatures of visuomotor action planning. We compared desynchronization for real tools versus closely matched pictures of the same objects, when the stimuli were positioned unoccluded versus behind a large transparent barrier that prevented immediate access to the stimuli. We found that, without the barrier in place, real objects elicited stronger μ and β desynchronization compared to pictures, both during stimulus presentation and after stimulus offset, replicating previous findings. Critically, however, with the barrier in place, this real object advantage was attenuated during the period of stimulus presentation, whereas the amplification in later periods remained. These results suggest that the “real object advantage” is driven initially by immediate actionability, whereas later differences perhaps reflect other, more inherent properties of real objects. The findings showcase how the use of richer multidimensional stimuli can provide a more complete and ecologically valid understanding of object vision.
Metacognitive Awareness of Difficulty in Action Selection: The Role of the Cingulo-opercular Network
Authors: Desender Kobe , Teuchies Martyn , Gonzalez-Garcia Carlos , De Baene Wouter , Demanet Jelle , Brass Marcel
Published: August 2021

The question whether and how we are able to monitor our own cognitive states (metacognition) has been a matter of debate for decades. Do we have direct access to our cognitive processes, or can we only infer them indirectly based on their consequences? In the current study, we wanted to investigate the brain circuits that underlie the metacognitive experience of fluency in action selection. To manipulate action-selection fluency, we used a subliminal response priming paradigm. On each trial, both male and female human participants additionally engaged in the metacognitive process of rating how hard they felt it was to respond to the target stimulus. Despite having no conscious awareness of the prime, results showed that participants rated incompatible trials (during which subliminal primes interfered with the required response) to be more difficult than compatible trials (where primes facilitated the required response), reflecting metacognitive awareness of difficulty. This increased sense of subjective difficulty was mirrored by increased activity in the rostral cingulate zone and the anterior insula, two regions that are functionally closely connected. Importantly, this reflected activations that were unique to subjective difficulty ratings and were not explained by RTs or prime–response compatibility. We interpret these findings in light of a possible grounding of the metacognitive judgment of fluency in action selection in interoceptive signals resulting from increased effort.
Post-Discharge Outcomes After Pancreatic Necrosectomy: A Single Institution Experience Following Endoscopic vs Open Debridement
Authors: Martinez Manuel , Medeiros Steven , Dove James , Shabahang Mohsen
Published: August 2021

Background

Pancreatic necrosectomy outcomes have been studied extensively; however, long-term results of these procedures have not been well characterized. Our study aimed to assess the outcomes at and after discharge for patients following necrosectomy.

Methods

Data from patients undergoing pancreatic necrosectomy at a single tertiary referral hospital from January 1, 2007, to June 1, 2019 were retrospectively analyzed. Patients were stratified into an open pancreatic necrosectomy (OPN) and an endoscopic pancreatic necrosectomy (EPN) group.

Results

Cohorts were composed of an OPN (n = 30) and EPN (n = 31) groups with a mean follow-up of 22 and 13.5 months, respectively. There was no statistically significant difference in the demographics or etiology of disease; however, the presence of severe sepsis and elevated BISAP scores was significantly higher in the OPN group (40% vs 13% p = .016, 37% vs 10% p = .012, respectively). There was no significant difference in discharge parameters or disposition other than a higher need for wound care in the OPN group (14% vs 0% p =< .0001). No significant difference in the number of patients who returned to baseline, 12-month ED visits, 12-month readmissions, medical comorbidities, or long-term survival was noted.

Conclusions

Previous studies have demonstrated that OPN patients have a higher severity of disease and higher inpatient mortality; however, this does not hold true once the acute phase of the illness has passed. Long-term medical comorbidities and survival of patients with necrotizing pancreatitis who endure the primary insult do not differ in long term, regardless of the debridement modality performed for source control.
Rates of homicide and homicide associated with severe mental illness in NSW between 1993 and 2016
Authors: Nielssen Olav , Lyons Georgia , Oldfield Katya , Johnson Anina , Dean Kimberlie , Large Matthew
Published: August 2021

Objective:

To describe the characteristics of offenders found not guilty on the grounds of mental illness (NGMI) in New South Wales and rates of NGMI and other homicide verdicts.

Method:

Demographic, legal and clinical data after referral to the NSW Mental Health Review Tribunal following an NGMI verdict for homicide matched with results from the National Homicide Monitoring Program.

Results:

Between 1993 and 2016, a total of 2159 homicide offenders were dealt with by the NSW courts, including 169 (7.8%) who were found NGMI. Over this period, the rate of non-NGMI homicide convictions fell from 1.83 per 100,000 per annum to 0.65 per 100,000 per annum (Kendall’s tau = −0.79, p ⩽ 0.001) while the rate of NGMI homicide fluctuated, with an average annual rate of about 0.1 per 100,000 per annum (Kendall’s tau = 0.17, p = 0.23). There was no association between the annual rates of NGMI and non-NGMI homicides (Pearson r = −0.3, p = 0.16) but falling rate of non-NGMI homicide meant that the proportion of NGMI offences doubled from 5.5% in the first 12 years to 11% in the second 12 years. Nearly all (88.7%) of those found NGMI had a schizophrenia-related psychosis. However, there were high rates of psychiatric comorbidity including substance use disorder (60.7%) and a history of a prior head injury (41.1%). Most (83.4%) of the NGMI offenders had previous contact with mental health services, but only half of these had received treatment with antipsychotic medication.

Conclusion:

The fall in conviction for homicide offences in the last 24 years has not been matched by a reduction in NGMI homicide verdicts. More assertive treatment of emerging psychosis and comorbid substance use disorders, and improved continuity of care of chronic psychosis might prevent some homicides.
Evaluating the Effect of Digital Transformation on Improvement of Service Trade in West Africa
Authors: Azu Nnanna P. , Nwauko Philip A.
Published: August 2021

Digital revolution is instrumental to the wave of globalisation and transformation of the global economy. But the pace of digital transformation and service trade is low in the West African region. This article investigates the effect of digital transformation on the development of service trade in the region. This research captured digitisation in two standpoints: internet penetration rate and mobile subscription rate. The Im-Pesaran-Shin unit-root test affirms that the model is appropriate for panel autoregressive distributed lag estimation method. Adopting pool mean group estimator, the results attest for the existence of cointegrations in the model. The estimations reveal that the effect of digitisation on service trade is a long-run phenomenon. While the result is robust with export, it is not consistent with import. The long-run positive impact of digitisation on service export ranges from 0.087% to 0.159%, depending on the proxy for digitisation. The overall short-run effect is not statistically significant in export and not robust in import. It is reportedly consistent in some countries but not robust with some others. The region needs to rally in adopting and adapting to the new face of technology to improve service trade.

JEL Codes: C23, F14, O33
Computer Prompt Software to Reduce Sedentary Behavior and Promote Physical Activity Among Desk-Based Workers: A Systematic Review
Authors: Taylor Wendell C. , Williams Jordan R. , Harris Lauren E. , Shegog Ross
Published: August 2021

Objective

Do computer prompt software programs at the workplace reduce sitting time and/or increase physical activity at work?

Background

Many products are promoted and being used in the workplace; however, their effectiveness and use are unknown or the evidence base that they work to change behavior is lacking.

Method

We searched for relevant papers published between 2005 and 2020. The inclusion criteria were computer prompt software programs installed as behavioral change interventions; interventions implemented during work hours and delivered through a work personal computer or laptop; and measures of sedentary behavior and/or physical activity. To minimize risk of bias, three recommended best-evidence synthesis criteria were used: random assignment, sample size, and external validity. Based on these criteria, articles were selected and evaluated.

Results

Six publications met the quality threshold for review. Seven articles did not meet the quality threshold. Four of the six included publications found that computer prompt software programs decreased sedentary behavior and/or increased physical activity. Two publications reported inconsistent results.

Conclusions

The promising results from this systematic review indicate that there is potential for computer prompt software programs to improve the health of desk-based workers. For conclusive findings, more high-quality, scientific studies are needed.

Application

The best-evidence publications in this review can serve as a guide in selecting and implementing computer prompt software programs at the workplace to decrease sedentary behavior and increase physical activity.
Dying by Suicide in Nursing Homes: A Preventable End of Life Outcome for Older Residents
Authors: Salvatore Tony
Published: August 2021

Suicide research and suicide prevention have given comparatively little attention to the older adult residents of nursing homes. This population is characterized by advanced age, significant infirmity, limited autonomy and social connections, and other factors associated with high suicide risk such as self-neglect. However, little is known of the actual incidence and prevalence of suicide in older adults in such residential care settings, partly because of how such deaths are reported. Suicide risk screenings are nominal, facility staff lack training to identify signs of suicidality, and suicide prevention programs are not common in the nursing home industry. These deficits can be remedied by increasing awareness among family members, facility caregivers, contracted providers, community aging services, accrediting and regulatory agencies, and residents.
Predicting atrial fibrillation after cardiac surgery: a scoping review of associated factors and systematic review of existing prediction models
Authors: Fleet Hugh , Pilcher David , Bellomo Rinaldo , Coulson Tim G
Published: August 2021

Introduction:

Postoperative atrial fibrillation (POAF) is common after cardiac surgery and associated with increased hospital length of stay, patient morbidity and mortality. We aimed to identify factors associated with POAF and evaluate the accuracy of available POAF prediction models.

Methods:

We screened articles from Ovid MEDLINE® and PubMed Central® (PMC) and included studies that evaluated risk factors associated with POAF or studies that designed or validated POAF prediction models. We only included studies in cardiac surgical patients with sample size n ⩾ 50 and a POAF outcome group ⩾20. We summarised factors that were associated with POAF and assessed prediction model performance by reviewing reported calibration and discriminative ability.

Results:

We reviewed 232 studies. Of these, 142 fulfilled the inclusion criteria. Age was frequently found to be associated with POAF, while most other variables showed contradictory findings, or were assessed in few studies. Overall, 15 studies specifically developed and/or validated 12 prediction models. Of these, all showed poor discrimination or absent calibration in predicting POAF in externally validated cohorts.

Conclusions:

Except for age, reporting of factors associated with POAF is inconsistent and often contradictory. Prediction models have low discrimination, missing calibration statistics, are at risk of bias and show limited clinical applicability. This suggests the need for studies that prospectively collect AF relevant data in large cohorts and then proceed to validate findings in external data sets.
Reactionary radicalism and the analysis of worker subjectivity in Marx’s critique of political economy
Authors: Granberg Magnus
Published: August 2021

This analysis starts off from the contemporary relevance of the theory of ‘the radicalism of tradition’, arguing that it presents a challenge to Marxism because Marxist work has not sufficiently attended to elements of a theory of worker subjectivity scattered in the critique of political economy. This theory is located on a lower level of abstraction than is commonly assumed and can be applied to subjective dynamics in labour militancy. However, this requires that some basic categories in Marx’s critique are reconsidered, especially those that do not seem immanent to the capitalist social formation, categories that appear, and have mostly been read, as the ahistorical ground on which properly social forms arise. Therefore, apparently ahistorical categories pertaining to use value and concrete labour’s use value for capital are explored to reconstruct a theory relating capital’s positing of labour to contemporary militancies that appropriate tradition. In contrast to the view of tradition as external to capital, the view advanced is that ‘reactionary radicalism’ relates to how capital, as totalizing social form, abstracts tradition. Furthermore, tradition is radicalized through a negative subjectivity inherent to the commodification of labour power and the real subsumption of labour; proletarian experience is a precondition of radicalized tradition.
“Advanced Marriage Technique”: Sex as a Perfectible Skill in Mid-twentieth-century American Marriage Manuals
Authors: Lavine Matthew
Published: August 2021

While earlier marital advice literature treated sexual intercourse as a matter of conditioned instinct, marriage manuals in the mid-twentieth century portrayed it as a skill, and one that was rarely cultivated adequately. The didactic, quantified, objectively examined and rule-bound approach to sex promulgated by these manuals parallels other ways in which Americans subjected their personal and intimate lives to the tutelage of experts. Anxieties about the stability of marriage and family life were both heightened and salved by the authoritative tone of scientific authority used in these books.