bluuebunny/crossref_metadata_2025 huggingface dataset:
COVID-19 cardiac injury and the use of colchicine
Authors: Anton-Vazquez Vanesa , Byrne Laura , Anderson Lisa , Hamzah Lisa
Published: February 2021

We report a case of cardiac injury in a 46-year-old man affected by COVID-19. The patient presented with shortness of breath and fever. ECG revealed sinus tachycardia with ventricular extrasystoles and T-wave inversion in anterior leads. Troponin T and N-terminal pro B-type natriuretic peptide were elevated. Transthoracic echocardiography showed severely reduced systolic function with an estimated left ventricle ejection fraction of 30%. A nasopharingeal swab was positive for SARS-CoV-2. On day 6, 11 days after onset of symptoms, the patient deteriorated clinically with new chest pain and type 1 respiratory failure. Treatment with colchicine 0.5 mg 8-hourly resulted in rapid clinical resolution. This case report highlights how cardiac injury can dominate the clinical picture in COVID-19 infection. The role of colchicine therapy should be further studied to determine its usefulness in reducing myocardial and possibly lung parenchymal inflammatory responses.
Applying improvement science to establish a resident sustained quality improvement (QI) educational model
Authors: Collins Caitlyn , Mathura Pamela , Ip Shannon , Kassam Narmin , Tapardel Anca
Published: February 2021

Background

Prior to 2017, internal medicine (IM) residents at the University of Alberta did not have a standardised quality improvement (QI) educational curriculum. Our goal was to use QI principles to develop a resident sustained curriculum using the Evidence-based Practice for Improving Quality (EPIQ) training course.

Methods

Three one-year Plan–Do–Study–Act (PDSA) cycles were conducted. The EPIQ course was delivered to postgraduate year (PGY) 1–3 residents (n=110, PDSA 1) in 2017, PGY-1 residents (n=27, PDSA 2) in 2018 and PGY-1 residents (n=28, PDSA 3) in 2019. Trained residents were recruited as facilitators for PDSA 2 and 3. Residents worked through potential QI projects that were later presented for evaluation. Precourse and postcourse surveys and tests were conducted to assess knowledge acquisition and curriculum satisfaction. Process, outcome and balancing measures were also evaluated.

Results

In PDSA 1, 98% felt they had acquired understanding of QI principles (56% increase), 94% of PGY-2 and PGY-3 residents preferred this QI curriculum compared with previous training, and 65% of residents expressed interest in pursuing a QI project (15% increase). In PDSA 2, tests scores of QI principles improved from 77.6% to 80%, and 40% of residents expressed interest in becoming a course facilitator. In PDSA 3, self-rated confidence with QI methodology improved from 53% to 75%. A total of 165 residents completed EPIQ training and 11 residents became course facilitators.

Conclusions

Having a structured QI curriculum and working through practical QI projects provided valuable QI training for residents. Feedback was positive, and with each PDSA cycle there was increased resident interest in QI. Developing this curriculum using validated QI tools highlighted areas of change opportunity thereby enhancing acceptance. As more cycles of EPIQ are delivered and more residents become facilitators, it is our aim to have this curriculum sustained by future residents.
Determination of optimal deployment strategy for REBOA in patients with non-compressible hemorrhage below the diaphragm
Authors: Johnson Nicholas L , Wade Charles E , Fox Erin E , Meyer David E , Fox Charles J , Moore Ernest E , Morrison Jonathan , Scalea Thomas , Bulger Eileen M , Inaba Kenji , Morse Bryan C , Moore Laura J
Published: February 2021

Background

Non-compressible truncal hemorrhage (NCTH) is the leading cause of preventable death after trauma. Resuscitative endovascular balloon occlusion of the aorta (REBOA) achieves temporary hemorrhage control, supporting cardiac and cerebral perfusion prior to definitive hemostasis. Aortic zone selection algorithms vary among institutions. We evaluated the efficacy of an algorithm for REBOA use.

Methods

A multicenter prospective, observational study conducted at six level 1 trauma centers over 12 months. Inclusion criteria were age >15 years with evidence of infradiaphragmatic NCTH needing emergent hemorrhage control within 60 min of ED arrival. An algorithm characterized by the results of focused assessment with sonography in trauma and pelvic X-ray was assessed post hoc for efficacy in a cohort of patients receiving REBOA.

Results

Of the 8166 patients screened, 78 patients had a REBOA placed. 21 patients were excluded, leaving 57 patients for analysis. The algorithm ensures REBOA deployment proximal to hemorrhage source to control bleeding in 98.2% of cases and accurately predicts the optimal REBOA zone in 78.9% of cases. If the algorithm was violated, bleeding was optimally controlled in only 43.8% (p=0.01). Three (75.0%) of the patients that received an inappropriate zone 1 REBOA died, two from multiple organ failure (MOF). All three patients that died with an inappropriate zone 3 REBOA died from exsanguination.

Discussion

This algorithm ensures proximal hemorrhage control and accurately predicts the primary source of hemorrhage. We propose a new algorithm that will be more inclusive. A zone 3 REBOA should not be performed when a zone 1 is indicated by the algorithm as 100% of these patients exsanguinated. MOF, perhaps from visceral ischemia in patients with an inappropriate zone 1 REBOA, may have been prevented with zone 3 placement or limited zone 1 occlusion time.

Level of evidence

Level III.
A simplified seismic design method for limited-ductility steel multi-tiered concentrically braced frames in moderate seismic regions
Authors: Derakhshan Houreh Eshagh , Imanpour Ali
Published: February 2021

Steel multi-tiered concentrically braced frames (MT-CBFs) represent a bracing configuration where two or more concentric bracing panels are stacked between the ground and roof levels in tall single-storey buildings. A large proportion of MT-CBFs in Canada are located in low-to-moderate seismic regions (seismic category 0–3) where limited ductility CBFs are often preferred in design. Nevertheless, brace tensile yielding may not occur in all tiers of such frames. Additionally, the analysis and design procedure adopted by the 2019 Canadian steel design standard (CSA S16-19) can become tedious in tall frames with multiple panels. In this paper, the seismic behaviour of limited ductility MT-CBFs in moderate seismic regions of Canada is examined to propose a simplified design method. A set of 16 prototype MT-CBFs is designed in accordance with CSA S16-19, excluding the design requirements prescribed for MT-CBF columns. Nonlinear dynamic analyses are then performed to examine their seismic response. Finally, an efficient design method is proposed in the framework of CSA S16-19.
Can uneven-aged management improve the economic performance of longleaf pine?
Authors: Susaeta Andres , Klizentyte Kotryna , Sharma Ajay , Adams Damian C.
Published: February 2021

Longleaf pine (Pinus palustris Mill.) is a keystone tree species in the Coastal Plain of the southern United States. To reverse habitat loss and restore critically important forest ecosystem services in this region dominated by private landownership, longleaf pine’s economic performance must be addressed. Uneven-aged forest management has been suggested as a viable alternative for longleaf pine, but evidence of its economic performance under uneven-aged versus even-aged management is lacking. Here, we compare the economic viability of three competing longleaf pine management scenarios — thinned even-aged, unthinned even-aged (conservation and non-conservation land objectives), and uneven-aged — considering timber and nontimber benefits. We find that managing existing uneven-aged longleaf pine forests with a 10-year cutting cycle is economically preferred to even-aged management for land conservation ($1643.9·ha−1 versus $1548.8 to $1641.6·ha−1). However, these estimates exclude costs associated with switching to uneven-aged management ($174.3 to $694.9·ha−1), which are considerable. Annual subsidies of between $5 and $22·ha−1 for 50 years would be required to offset costs of conversion to uneven-aged management. For establishment of new longleaf pine stands, an uneven-aged scenario would be the economically preferred management approach, providing higher economic gains ($176.9·ha−1) than unthinned, high-density even-aged management when the primary objective is timber production.
No support for relatedness and kin selection to explain high rates of conspecific brood parasitism in colonial Red-breasted Mergansers (Mergus serrator)
Authors: Noel Kristen , Titman Rodger D. , Craik Shawn R.
Published: February 2021

Conspecific brood parasitism (CBP) has been observed in approximately half of all species of waterfowl, a philopatric group in which breeding females are frequently locally related. It has been suggested that kin selection can facilitate the evolution of CBP in waterfowl via fitness benefits for the host and parasite. One model demonstrates that discrimination of related and unrelated parasites by the host must be sufficient for kinship to promote CBP, provided that costs of brood parasitism to host fitness are sufficiently low. We parameterized the model using demographic data and behavioural observations from a population of colonial Red-breasted Mergansers (Mergus serrator Linnaeus, 1758) in which 47% of nests were parasitized by conspecifics. The costs of 1–3 foreign eggs to host hatching success were generally small (decline of 1.8% per additional egg). Nevertheless, model outputs revealed that brood parasites maximize their inclusive fitness by avoiding nests of relatives, primarily because of constraints on a host’s ability to detect parasites at the nest. Indeed, hosts spent <8% of the diurnal period at the nest during egg laying, a period when parasite activity is greatest. It is thus highly unlikely that relatedness and kin selection promote brood parasitism in this population.
Optical properties of rotating Hayward-de Sitter black hole surrounded by quintessence
Authors: Chen Yuan , Zhang He-Xu , Ma Tian-Chi , Deng Jian-Bo
Published: February 2021

In this paper, we discussed optical properties of the nonlinear magnetic charged black hole surrounded by quintessence with a nonzero cosmological constant [Formula: see text]. Setting the state parameter [Formula: see text], we studied the horizons, the photon region and the shadow of this black hole. It turned out that for a fixed quintessential parameter [Formula: see text], in a certain range, with the increase of the rotation parameter [Formula: see text] and magnetic charge [Formula: see text], the inner horizon radius increases while the outer horizon radius decreases. The cosmological horizon [Formula: see text] decreases when [Formula: see text] or [Formula: see text] increases and it increases slightly when [Formula: see text] and [Formula: see text] increase. The shapes of photon region were then studied and depicted through graphical illustrations. Finally, we discussed the effects of the quintessential parameter [Formula: see text] and the cosmological constant [Formula: see text] on the shadow of this black hole with a fixed observer position in the domain of outer communication.
First principle studies on the structures, electronic properties and Raman spectrums of monolayer WX2 (X = S, Se, Te) under strain condition
Authors: Huang Shan , Wang Yanping , Fan Yawen , Feng Jinjiao , Zhao Hui , Zhang Yang
Published: February 2021

The two-dimensional transition-metal dichalcogenides (2D TMDs) WX2 (S, Se, Te) have received extensive attention and research since they have excellent physical properties and have been widely used in the fields of photoelectronics. Monolayer (ML) WX2 has excellent physical properties and can be modified by simple strain. Using the first principles based on density functional theory (DFT), this paper mainly studies the electronic properties of ML WS2, WSe2 and Wte2. We also study the stabilities of three ML structures, the changes of Raman spectra and the movement of Raman peaks under biaxial tensile and compressive strains. Under the control of strain not only does the bandgap changes, but also the band properties shift between the direct bandgap and the indirect bandgap. With the increase of strain, bond length and bond angle change in the opposite trend. At the same time, we also studied the phonon dispersion relations of WX2 under different strains. We found that three structures showed good thermodynamic stabilities under the tensile strain (1–10%). When the compressive strain is 2%, one of the acoustic modes of WS2 or Wse2 becomes imaginary at [Formula: see text] point, which indicates the structural instability. When tensile strain Raman summit blueshifts and when compressive strains, the redshift occurs.
Design of Z-Source Inverter-Based Dynamic Voltage Restorer Circuitry with R-SOGI Control Scheme for Enrichment of Power Quality
Authors: Sathik Basha A. , Ramasamy M.
Published: February 2021

Increased utilization of nonlinear loads in the power distribution system with profound integration of renewable energy requires improved power quality control. This paper proposes a Reformed Second Order Generalized Integrated (R-SOGI) control scheme for enhancing the output of the Dynamic Voltage Restorer (DVR) for the objective of achieving the desired sinusoidal voltage wave shape at the common point of services and harmonic reduction. The DVR incorporates a Solar Photovoltaic (SPV) system using the Z-source Inverter (ZSI), providing the necessary active power to mitigate the voltage sag/swell and power demand. ZSI offers step-down as well as step-up abilities, it makes the converters to operate in the conditions of shoot-through. Therefore, the application of ZSI-based DVR topology seems very promising. The compensating reference voltage is generated by the R-SOGI algorithm, which offers superior output under conditions for grid voltage irregularities, including voltage sag/swell and unbalanced and distorted utility grid voltages. In comparison to DVR based on the VSI voltage inverter (VSI), the response from ZSI-DVR to a reduction of voltage distortions and harmonics is investigated. An experimental SPV ZSI-DVR prototype is developed in the laboratory to check the effectiveness of the controller and is tested under balanced and unbalanced supply and dynamic load conditions.
A SUPERHYDROPHOBIC COATING ON TITANIUM ALLOYS BY SIMPLE CHEMICAL ETCHING
Authors: ZHANG YUFENG , CHEN GUOLIANG , WANG YAMING , ZOU YONGCHUN
Published: February 2021

In the present study, a scalable-manufactured and environmental-friendly method was proposed to fabricate the superhydrophobic coating on titanium alloy. The hierarchical binary surface structures were obtained by hydrothermal treatment of titanium alloy with oxalic acid and sodium hydroxide solutions successively. The hierarchical structure surfaces after fluoroalkyl-silane modification possessed a maximum contact angle of 158.7∘ and a sliding angle of 4.3∘. The low contact angle hysteresis surface can lead to efficient self-cleaning performance, which was confirmed by the bounce and roll off of water droplet on the surface. Furthermore, the anticorrosion behaviors of the superhydrophobic coating in 3.5[Formula: see text]wt.% NaCl solution was evaluated by the electrochemical impedance spectroscopy (EIS). It was found that the superhydrophobic coating can maintain its superhydrophobic state (150∘) within 48 h, thereby effectively preventing the corrosive medium from penetrating into the coating. This simple yet fast anti-corrosion/self-cleaning superhydrophobic coating manufacturing strategy will enlighten its potential application in the engineering fields.
CLOSED FORM OPTIMAL EXERCISE BOUNDARY OF THE AMERICAN PUT OPTION
Authors: KITAPBAYEV YERKIN
Published: February 2021

We present three models of stock price with time-dependent interest rate, dividend yield, and volatility, respectively, that allow for explicit forms of the optimal exercise boundary of the finite maturity American put option. The optimal exercise boundary satisfies the nonlinear integral equation of Volterra type. We choose time-dependent parameters of the model so that the integral equation for the exercise boundary can be solved in the closed form. We also define the contracts of put type with time-dependent strike price that support the explicit optimal exercise boundary.
Negacyclic codes of prime power length over the finite non-commutative chain ring 𝔽pm[u,𝜃] 〈u2〉
Authors: Inchaisri Teeramet , Phuto Jirayu , Klin-Eam Chakkrid
Published: February 2021

In this paper, we focus on the algebraic structure of left negacyclic codes of length [Formula: see text] over the finite non-commutative chain ring [Formula: see text] where [Formula: see text] is an automorphism on [Formula: see text]. After that, the number of codewords of all left negacyclic codes is obtained. For each left negacyclic code, we also obtain the structure of its right dual code. In the remaining result, the number of distinct left negacyclic codes is given. Finally, a one-to-one correspondence between left negacyclic and left [Formula: see text]-constacyclic codes of length [Formula: see text] over [Formula: see text] is constructed via ring isomorphism, which carries over the results regarding left negacyclic codes corresponding to left [Formula: see text]-constacyclic codes of length [Formula: see text] over [Formula: see text] where [Formula: see text] is a nonzero element of the field [Formula: see text] such that [Formula: see text].
Effects of Dexmedetomidine on Perioperative Stress Response and Cellular Immunity in Elderly Patients with Posterior Lumbar Surgery
Authors: Huang Chunyan , Lin Mei , Wang Xiaoying , Liu Xiaodong , Zhang Haijiao , Liu Su , Huang Chunjin
Published: February 2021

The aim of this study was to investigate the effects of dexmedetomidine on perioperative stress response and cellular immunity in elderly patients with posterior lumbar surgery. Sixty patients with lumbar degenerative disease requiring posterior lumbar surgery were included and randomly divided into the dexmedetomidine group (the test group, [Formula: see text]) and the control group ([Formula: see text]). After the experimental group entered the room, dexmedetomidine was intravenously pumped 10[Formula: see text]min before induction of anesthesia and dexmedetomidine was continuously pumped after anesthesia. The control group replaced dexmedetomidine with the same amount of normal saline, and the other operations were exactly the same as the experimental group. Hemodynamic parameters were routinely monitored and the percentages of T lymphocyte subsets were analyzed by flow cytometry. Samples for stress response parameters were sent to the Clinical Laboratory of our hospital, and perioperative pain, postoperative adverse reactions and complications were evaluated during the study. The levels of postoperative stress hormones, including noradrenaline (NE), epinephrine (E), cortisol (Cor) and acetylcholine (Ach), were reduced in the test group compared with those in the control group ([Formula: see text]). Proportions of CD3[Formula: see text], CD4[Formula: see text], CD8[Formula: see text] and NK as well as the CD4[Formula: see text]/CD8[Formula: see text] in the control group were significantly decreased at postoperative Day 1 (T6), Day 3 (T7) and Day 7 (T8) compared with those at preoperative Day 1 (T-1) ([Formula: see text]), while the proportions of CD4[Formula: see text] and NK in the test group were significantly increased at T6, T7 and T8 compared with those at T-1 ([Formula: see text]). The mean arterial pressure (MAP) of the test group was decreased compared with that of the control group at each time point ([Formula: see text]). After the operation, the heart rate (HR) of the patients in the test group was significantly decreased compared with the control group ([Formula: see text]) and the VAS score of the control group were increased compared with the test group at each time point ([Formula: see text]). Dexmedetomidine can decrease the stress response and improve postoperative cellular immune function in patients with posterior lumbar surgery by reducing postoperative stress hormones to alleviate the postoperative cellular immunosuppression and the pain in patients.
Multivariate Hawkes process model of market participants behavior in the high frequency world
Authors: Chakravarty Sugato , Lee Kiseop , Xi Yang
Published: February 2021

We propose a multivariate Hawkes process to model the interaction between the non-high frequency traders (NHFTs) behavior (Buy and sell) and high frequency traders (HFTs) behavior (Buy and sell). We apply our model to the intraday transaction data of the public sector banks stock in India, which is sampled from March 2012 to June 2012. We find that the mutually-exciting NHFT and HFT behaviors benefit the stocks, which have better average return above the average return of the public sector bank index. We further identify the granger causality relationship for mutually exciting dominating stocks that HFTs activities cause the activities of NHFTs. In other words, NHFTs are market followers in those stocks.
Conjugated Polyelectrolyte Combined with Ionic Liquid as the Hole Transport Layer for Efficient Inverted Perovskite Solar Cells
Authors: Jian Hongmei , Chen Hao , He Ling , Zhao Chengjie , Chen Jiang , Jiu Tonggang , Tao Guo-Hong
Published: February 2021

Conjugated polyelectrolytes (CPEs) are promising hole transport materials for perovskite solar cells, whereas their severe intermolecular aggregation significantly affects the device performance. Here, long-chain alkyl imidazolium ionic liquid (IL) of 1-dodecyl-3-methylimidazolium bromide ([C12mim]Br) and conjugated polyelectrolytes of potassium poly[3-(4-carboxylatebutyl)thiophene (P3CT-K) are combined with different mass ratios. The UV–vis spectra and dynamic light scattering studies indicate that the aggregation behavior of P3CT-K is suppressed by IL, thus obtaining a smoother hole transport layer for the latter device fabrication, which efficiently improves the film quality of perovskite absorber and enhances the hole transport at the interface. As a consequence, the inverted PSCs based on P3CT-K/IL film as the HTL show considerable improvement in power conversion efficiency (PCE), from 16.21% to 18.81%, compared with pristine P3CT-K based device. These findings indicate that IL can effectively inhibit the aggregation of CPEs, providing a new pathway to further improve the performance of PSCs based on CPEs interlayer.
Reasons for Permanent Teeth Extractions and Related Factors among Adult Patients in the Eastern Province of Saudi Arabia
Authors: Aljafar Abdullah , Alibrahim Hassan , Alahmed Ammar , AbuAli Ahmad , Nazir Muhammad , Alakel Ahmed , Almas Khalid
Published: February 2021

Objective. To evaluate the reasons for permanent teeth extractions and related factors among adult patients visiting dental clinics in the Eastern Province of Saudi Arabia. Materials and Methods. This retrospective cross-sectional study included data of patients who underwent teeth extractions. Data were collected from public and private dental clinics in different cities of the Eastern Province of Saudi Arabia (January–March 2020). The demographic information of patients and their reasons for teeth extractions were obtained from participating dentists. Results. The study included data of 696 patients with 55.9% of males and 44.1% of females. The mean number of teeth extractions in the sample was 1.86 ± 1.8, and it increased significantly with advancing age (

P
≤
0.001

). Saudi (1.97 ± 1.98) versus non-Saudi patients (1.55 ± 1.11) (

P
=
0.02

) and patients in public practice (2.03 ± 1.95) versus patients in private practice (1.50 ± 1.38) (

P
≤
0.001

) showed significantly higher teeth extractions. Dental caries was the most common reason for teeth extractions (49.1%), followed by remaining roots (18.5%), periodontal disease (18.4%), and impactions (7.2%). Most commonly extracted teeth included tooth # 30 (9.8%), followed by tooth #16 (9.6%), tooth # 1 (8.8%), tooth # 19 (8.3%), and tooth # 4 (8.3%). On the other hand, upper incisors were the least commonly extracted teeth. Conclusions. Dental caries, remaining roots, periodontal disease, and impactions were the most common reasons for teeth extractions in our sample of patients. The extractions increased significantly with increasing age. Saudis and patients in public clinics underwent significantly higher teeth extractions. Measures aimed at the prevention and treatment of oral conditions can help reduce teeth extractions and improve the quality of life of patients.
The Piston Ring‐Cylinder Bore Interface Leakage of Bent‐Axis Piston Pumps Based on Elastohydrodynamic Lubrication and Rotation Speed
Authors: Qing Lvjun , Gu Lichen , Wang Yan , Xue Wei , Lei Zhufeng
Published: February 2021

The bent‐axis piston pump is the core component of electrohydrostatic actuators (EHA) in aerospace applications, and its wear of key friction interfaces is greatly related to the healthy operation of pumps. The leakage of the piston ring‐cylinder bore interface (PRCB), as the important part of the return oil flow of the pump house that commonly assesses the wear of key friction interfaces in piston pumps, is changed with the rotation speed. Thus, the wear of key friction interfaces is usually inaccurate by using the leakage of PRCB. In order to obtain the relationship between the PRCB leakage and the rotation speed, an elastohydrodynamic lubrication model is proposed. First, the proposed model includes a minimum film thickness model of PRCB to analyze the dynamic change of oil film of PRCB when subject to the elastohydrodynamic lubrication. After that, a mathematical model of PRCB is induced by combining the minimum film thickness model with the flow equation, which helps produce the effects of the oil film on the leakage of PRCB. The proposed model is verified by numerical simulation and experiment. The results show that the leakage of PRCB has a negative effect on the return oil flow of the pump case in the range of rotation speed of 700–1300 r/min and discharge pressure of 10–20 MPa. Furthermore, the leakage of PRCB is proportional to the rotation speed, but the return oil flow of the pump case is decreased. The effects of rotation speed are enhanced under the high discharge pressure conditions.
Real‐Time System Prediction for Heart Rate Using Deep Learning and Stream Processing Platforms
Authors: Alharbi Abdullah , Alosaimi Wael , Sahal Radhya , Saleh Hager
Published: February 2021

Low heart rate causes a risk of death, heart disease, and cardiovascular diseases. Therefore, monitoring the heart rate is critical because of the heart’s function to discover its irregularity to detect the health problems early. Rapid technological advancement (e.g., artificial intelligence and stream processing technologies) allows healthcare sectors to consolidate and analyze massive health‐based data to discover risks by making more accurate predictions. Therefore, this work proposes a real‐time prediction system for heart rate, which helps the medical care providers and patients avoid heart rate risk in real time. The proposed system consists of two phases, namely, an offline phase and an online phase. The offline phase targets developing the model using different forecasting techniques to find the lowest root mean square error. The heart rate time‐series dataset is extracted from Medical Information Mart for Intensive Care (MIMIC‐II). Recurrent neural network (RNN), long short‐term memory (LSTM), gated recurrent units (GRU), and bidirectional long short‐term memory (BI‐LSTM) are applied to heart rate time series. For the online phase, Apache Kafka and Apache Spark have been used to predict the heart rate in advance based on the best developed model. According to the experimental results, the GRU with three layers has recorded the best performance. Consequently, GRU with three layers has been used to predict heart rate 5 minutes in advance.
A New Theoretical Model of Rock Burst-Prone Roadway Support and Its Application
Authors: Gao Mingshi , He Yongliang , Xu Dong , Yu Xin
Published: February 2021

A rock burst usually causes a roadway collapse or even an instant blockage. When the deformation energy accumulated in the surrounding rock exceeds the minimum energy required for the dynamic destruction of the surrounding rock of a roadway, a rock burst accident will occur. According to statistics, 85% of rock burst accidents occur in roadways. This paper establishes a strong-soft-strong structural model for the rock burst stability control of the surrounding rock of a roadway, and the anti-impact and antiseismic mechanisms of the mechanical model are analysed. The strength, stress transfer, deformation, and energy dissipation characteristics of the strong-soft-strong structure are studied. The stress criterion and energy criterion of rock burst failure in small internal structures are derived for roadway support design. The support scheme of “anchor cable active support + hydraulic lifting support + soft structure energy absorption” is proposed. A steel pipe can be inserted into a borehole drilled into the small internal structure to realize the proposed innovative protection technology for small internal structures by creating a soft structure that can release, absorb, and transfer the pressure by repeatedly cracking the coal and rock mass. The innovation of cracking technology for soft roadway structures has been realized. The roadway tested with this strong-soft-strong enhanced surrounding rock control technology met the production requirements during the mining period. The field test was successful, and the expected support effect was achieved. This work provides a reference for roadway support under similar conditions and can be popularized and applied.
Limb Lengthening after Primary Total Knee Arthroplasty: Customized Patient-Specific Instrumentation Does Not Affect Expected Limb Lengthening
Authors: Fang Christopher , McAlpine Kenneth , Gustin Michael , Niu Ruijia , Freccero David , Gordon Matthew , Smith Eric L.
Published: February 2021

Introduction. Expectations for limb length differences after TKA are important for patient perception and outcomes. Limb length discrepancies may occur due to postoperative leg length increases, which can lead to decreased patient functionality and satisfaction and even possible litigation. The purpose of this study is to examine the frequency and extent of limb lengthening among various preoperative deformities and between two different implant systems. Methods. Preoperative and postoperative full-length standing radiographs were obtained between August 2018 and August 2019 to measure mechanical axis and limb length of operative limbs. Demographic information such as age, sex, and BMI was also collected. Patients were grouped into categories for pre- and postoperative subgroup analysis: valgus, varus, customized implant, and conventional implant. Regression analysis was performed to evaluate significant relationships. Results. Of the 121 primary TKAs analyzed, 62% of the knees showed an increase in limb length after TKA, with an average lengthening of 5.32 mm. Preoperative varus alignment was associated with a mean lengthening of 3.14 mm, while preoperative valgus alignment was associated with a mean lengthening of 16.2 mm. Overall, there were no statistically significant differences in limb lengths pre- and postoperatively (

p

 = 0.23) and no significant changes in limb length for any subgroup. Further, no variables were associated with limb length changes (

p

 = 0.49), including the use of customized implants (

p

 = 0.2). Conclusions. Limb lengthening after TKA is common and, on average, occurs more significantly in valgus knees. No significant difference in limb lengthening could be demonstrated using customized over conventional implants. Preoperative counseling is important to manage patient expectations.
Experimental Investigation of Permeability Evolution on Sandstone in Triaxial and Long-Term Dissolution Experiment
Authors: Shi Ji , Zhang Jianhua , Zhang Chunyang , Jiang Tingting , Huang Gang
Published: February 2021

The temporal permeability and damage evolutions of low-permeability sandstone cores during triaxial and long-term dissolution experiments were measured using a triaxial-flow system. Three triaxial experiments were performed on sandstone cores having initial permeability ranging from

78
×

10

−
18

 

m

2

to

120
×

10

−
18

 

m

2

. Two sets of long-term dissolution experiments were conducted on cracked sandstone cores. All dissolution experiments were performed at room temperature and using a 10 g/L H2SO4 and 0.2 g/L H2O2 input solution. Permeability evolution was determined using Darcy’s law. The cores experienced an average increase of 25% in permeability in the dissolution experiment and 900%~1500% increase at the end of the experiment. The dissolution was fairly homogeneous during the long-term experiments whether on the 1 mm scale or the 10 μm scale. The relationship between damage and permeability was speculated and its correlation coefficient has been proved to be close to 1. These results suggest that hydraulic fracturing works well in permeability increase in low-permeability sandstone reservoir.
Study on the Expression Differences and the Correlation with H2BE Gene of Th Related Cytokines in SSDHS and LDSDS TCM-Syndromes of CHB Patients
Authors: Liu Chao , Zheng Yanfeng , Li Xia , Li Baixue , Wen Li , Wang Dong , Feng Quansheng , Jiang Cen
Published: February 2021

Although our previous studies revealed that H2BE exhibited significantly differential expression between two CHB TCM-syndromes: Spleen-stomach dampness-heat syndrome, SSDHS and liver-depression spleen-deficiency syndrome, LDSDS, the underlying mechanisms remain largely unknown. Recent studies showed that dynamic expression fluctuation of Th related cytokines in CHB TCM-syndromes, and furthermore, their expression levels were largely regulated by H2BE. This study aims to detect the expression level differences of Th related cytokines between these two TCM-syndromes and further investigate the underlying regulatory mechanisms. The expression levels of the four Th related cytokines and H2BE were analyzed and the protein-protein interaction networks between H2BE and the four cytokines were constructed. Our results suggested that almost all the cytokines were significantly upregulated compared with the healthy groupP<0.05. Interestingly, among the four cytokines, only IL-4 and INF-γ showed statistical significance between these two syndromes. The protein-protein interaction networks demonstrated that H2BE was indirectly associated with IL-4 and IL-10, and H2BE may regulate the expression levels of cytokines through GATA3. Taken together, our results indicated that IL-4 and INF-γ are two representative cytokines that may serve as two potential biochemical indicators of SSDHS and LDSDS in CHB patients; except what has been reported, our study found that one possible way for H2BE to regulate the expression of cytokines is to interact with GATA3 directly or indirectly.
Research on Permeability Coefficient of Heterogeneous Geomaterials Based on Digital Images
Authors: Liu Bowen , Chen Junbin , Ding Xinpin
Published: February 2021

According to the relationship between permeability and porosity of geotechnical materials, a finite element model representing pore and solid particles is generated randomly according to the porosity of a given finite element calculation model. According to Darcy’s law of flow distribution and steady seepage in the finite element random simulation section, the equivalent permeability coefficients at different porosities are calculated, and the relationship between the equivalent permeability coefficient and the porosity of rock and soil is studied. The results show that the equivalent permeability coefficient is proportional to the porosity with the same pore size. In order to study the seepage characteristics of structural planes of nonmaterial geotechnical materials in different strata contact zones, the formulas for calculating the deformation parameters and permeability coefficients of heterogeneous rock masses with single nonmaterial geotechnical materials are deduced theoretically, and the correctness and applicability of the formulas are verified by experiments. The rock mass sample selected in this paper is granite, which is simulated and analyzed by sandstone in the experiment. The results show that the permeability coefficients of coarse sandstone, fine sandstone, and heterogeneous rock mass are different under the same water pressure and confining pressure. This shows that the lithology on both sides of the nonmaterial geotechnical material surface has a significant influence on the permeability of the nonmaterial geotechnical material rock mass; the permeability coefficient of the nonmaterial geotechnical material rock mass decreases with the increase of confining pressure, the numerical change is limited to a certain confining pressure range, and the permeability coefficient tends to be stable when the confining pressure reaches a certain value. Comparing the theoretical calculation value of permeability coefficient of rock mass with the experimental result, it is found that the two values are in good agreement, which indicates the correctness and applicability of the theoretical calculation formula of permeability coefficient of rock mass of single intangible geotechnical material.
Optimal Coordinated Energy Management in Active Distribution System with Battery Energy Storage and Price-Responsive Demand
Authors: Xing Yahong , Zhao Haibo , Shen Zeyuan , Zhang Lin , Zhang Zhi , Li Qi , Wu Se
Published: February 2021

Contemporary distribution networks can be seen with diverse dispatchable and nondispatchable energy resources. The coordinated scheduling of these dispatchable resources, together with nondispatchable resources, can provide several technoeconomic and social benefits. Since battery energy storage systems (BESSs) and microturbine units (MT units) are capital-intensive, a thorough investigation of their coordinated scheduling under the economic criterion will be a challenging task while considering dynamic electricity prices and uncertainties of renewable power generation and load demand. This paper proposes a comprehensive methodological framework for optimal coordinated scheduling of BESSs with MT unit considering existing renewable energy resources and dynamic electricity prices to maximize the daily profit function of the utility by employing a recently explored modified African buffalo optimization algorithm. The key attributes of the proposed methodology are comprised of mean price-based adaptive scheduling embedded within a decision mechanism system (DMS) to maximize arbitrage benefits. DMS keeps track of system states as a priori, thus resulting in an artificial intelligence-based solution technique for sequential optimization. Further, a novel concept of fictitious charges is also proposed to restrict the counterproductive operational management of BESSs. The proposed model and method are demonstrated on the 33-bus distribution system, and the obtained results verify the effectiveness of the proposed methodology.
Benzothiazole (BTH) Induced Resistance of Navel Orange Fruit and Maintained Fruit Quality during Storage
Authors: Du Huaying , Sun Ying , Yang Rui , Zhang Wei , Wan Chunpeng , Chen Jinyin , Kahramanoğlu İbrahim , Zhu Liqin
Published: February 2021

Current research aimed at studying the effect of benzothiazole (BTH) on the fruit quality and resistance against Penicillium italicum (P. italicum). Recently, a synthetically prepared novel BTH was introduced that elicits the induction of resistance against various diseases of fruits. However, little was reported on the effect of BTH on the disease resistance and fruit quality of postharvest navel orange fruit. In this study, 50 mg·L−1 BTH significantly reduced the decay rate of fruits during 36 days of storage at 20 ± 0.5°C (

P
<
0.05

). BTH markedly inhibited the weight loss rate in fruits (

P
<
0.05

) and effectively maintained higher soluble solid content (SSC), titratable acid (TA), and vitamin C (VC) content compared with control navel orange fruits. Further, BTH significantly suppressed the increase of disease incidence and lesion area of orange fruits challenged with P. italicum (

P
<
0.05

). BTH treatment significantly enhanced antioxidant capacity (DPPH, ABTS radical scavenging activity, and reducing power), and superoxide dismutase (SOD) and peroxidase (POD) activities were significantly increased, while the activity of catalase (CAT) was opposite to the former (

P
<
0.05

). The activities of β-1,3-glucanase (GLU), phenylalanine ammonia-lyase (PAL), and chalcone isomerase (CHT) were significantly higher in BTH-treated navel orange fruits (

P
<
0.05

). Our results suggested that BTH treatment may be a promising treatment for maintaining the quality and inhibiting blue mold of postharvest navel orange in the future.
14‐Bit Fully Differential SAR ADC with PGA Used in Readout Circuit of CMOS Image Sensor
Authors: Zhang Xiaowei , Fan Wei , Xi Jianxiong , He Lenian
Published: February 2021

This paper proposes a 14‐bit fully differential Successive Approximation Register (SAR) Analog‐to‐Digital Converter (ADC) with a programmable gain amplifier (PGA) used in the readout circuit of CMOS image sensor (CIS). SAR ADC adopts two‐step scaled‐reference voltages to realize 14‐bit conversion, aimed at reducing the scale of capacitor array and avoiding using calibration to mitigate the impact of offset and mismatch. However, the reference voltage self‐calibration algorithm is applied on the design to guarantee the precision of reference voltages, which affects the results of conversion. The three‐way PGA provides three types of gains: 3x, 4x, and 6x, and samples at the same time to get three columns of pixel signal and increase the system speed. The pixel array of the mentioned CIS is 1026 × 1024, and the pixel pitch is 12.5 μm × 12.5 μm. The prototype chip is fabricated in the 180 nm CMOS process, and both digital and analog voltages are 3.3 V. The total area of the chip is 6.25 × 18.38 mm2. At 150 kS/s sampling rate, the SNR of SAR ADC is 71.72 dB and the SFDR is 82.91 dB. What is more, the single SAR ADC consumes 477.2 uW with the 4.8 VPP differential input signal and the total power consumption of the CIS is about 613 mW.
Pressure Behavior Analysis of Permeability Changes Due to Sand Production in Offshore Loose Sandstone Reservoirs Using Boundary-Element Method
Authors: Yan Zhenghe , Cao Chong , Xie Mingying , Jia Pin , Liu Guotao , Wei Xihui , Cheng Linsong , Tu Zhiyong
Published: February 2021

In recent years, sand production has been frequently observed in offshore weakly consolidated sandstone reservoirs. Permeability changes due to sand migration seriously affect the confidence in well test interpretation, production forecasts, and oilfield development plan schedules. The purpose of this paper is to propose a comprehensive model of coupled sand migration, stress sensitivity, and high viscosity oil and to study the effect of sand production induced permeability zoning on transient pressure behavior by combining discrete boundary and discrete wellbore with the boundary element method. In this two-zone composite model, the reservoir can be divided into the inner zone with the improved permeability due to sand migration and the outer zone with initial reservoir permeability. The multifactor effects of stress-sensitive, highly viscous oil, sand migration, and horizontal well are included in this model. Thus, the seepage equation presents a highly nonlinear and difficult to obtain an accurate analytical solution. In this paper, the boundary element method (BEM) is introduced to separate the boundary and wellbore, and the semianalytical solution of the hybrid model is obtained. The comparative analysis of measured pressure curve fitting from a horizontal well, located in the eastern of the South China Sea, proves that this comprehensive model can be used for pressure transient analysis of the weakly consolidated sandstone reservoir. The flow regime analysis indicates that a two-zone composite system may develop seven flow regimes: the wellbore storage stage, early-time radial stage, first transition stage, inner linear stage, inner pseudoradial flow, transition flow from the inner area to the outer area, and outer pseudoradial flow. Sensitivity analysis indicates that the smaller the sand production radius, the shorter the duration of the transition flow from the inner to the outer zone, which suggests the well is mainly affected by the outer boundary in the later period. The larger the permeability ratio, the higher the pressure curves may move up.
A Rare Paraspinal Desmoid Tumour following Instrumented Scoliosis Correction in an Adolescent
Authors: McCabe Fergus J. , Hussey Alan J. , McCabe John P.
Published: February 2021

Desmoid tumours are benign neoplasms of myofibroblasts, often occurring after soft-tissue trauma. Rarely, desmoid tumours can occur following operative intervention, including spine surgery. In this case report, we describe the first reported case of desmoid tumour following scoliosis corrective surgery in an adolescent.
Investigation of Flexural Capacity of Concrete Containing Liquid Silicone Rubber
Authors: Khaloo Alireza , Parvin Darabad Yaser
Published: February 2021

Despite the great use of concrete, tensile strength and low flexibility and brittleness are its weaknesses. Many solutions have been provided to eliminate the mentioned defects. In order to increase the flexibility of concrete in previous studies, crushed rubber tire particles have been added to concrete. Recycling car tires helps the environment and makes concrete much more flexible than regular concrete. In this research, silicone rubber has been replaced by 0%, 2%, 4%, 8%, 12.5%, 25%, and 50% of mineral aggregates. This rubber was initially in liquid form, which, after mixing with ordinary concrete, dispersed into the concrete texture and formed a uniform mixture, and this liquid rubber became a flexible solid after 24 hours. Concrete containing silicone rubber is a new composite with new properties, and in this research, it is called Hybrid Silicone Rubber Concrete (HSRC). Also, to evaluate the effect of aggregate size in making experimental specimens, two coarse to fine aggregate ratios of G/S = 0.7, 1.1 were considered. Flexural strength tests were performed on hardened concrete beam specimens. The results showed that, with increasing the amount of silicone rubber in concrete, flexural strength decreased and this percentage of strength reduction was compared with the percentage of reduction in compression and splitting tensile strength. It was found that the reduction of flexural strength was less than compression and splitting tensile strength. Larger deformation was observed during all tests when the concentration of silicone rubber increased. It was observed that the higher the amount of silicone rubber in the specimens, the less noise and the less separation of aggregates with which the failure of the specimens was associated.
Similarity Solutions to Nonlinear Diffusion/Harry Dym Fractional Equations
Authors: Yue Chao , Liu Guijuan , Li Kun , Dong Hanhui
Published: February 2021

By using scalar similarity transformation, nonlinear model of time-fractional diffusion/Harry Dym equation is transformed to corresponding ordinary fractional differential equations, from which a travelling-wave similarity solution of time-fractional Harry Dym equation is presented. Furthermore, numerical solutions of time-fractional diffusion equation are discussed. Again, through another similarity transformation, nonlinear model of space-fractional diffusion/Harry Dym equation is turned into corresponding ordinary differential equations, whose two similarity solutions are also worked out.