bluuebunny/crossref_metadata_2025 huggingface dataset:
Brief hypoxia in late gestation sheep causes prolonged disruption of fetal electrographic, breathing behaviours and can result in early labour
Authors: Baburamani Ana A. , Tran Nhi T. , Castillo‐Melendez Margie , Yawno Tamara , Walker David W.
Published: May 2021

Key points

Brief episodes of severe fetal hypoxia can arise in late gestation as a result of interruption of normal umbilical blood flow

Systemic parameters and blood chemistry indicate complete recovery within 1–2 hours, although the long‐term effects on fetal brain functions are unknown

Fetal sheep were subjected to umbilical cord occlusion (UCO) for 10 min at 131 days of gestation, and then monitored intensively until onset of labour or delivery (<145 days of gestation)

Normal patterns of fetal behaviour, including breathing movements, episodes of high and low voltage electorcortical activity, eye movements and postural (neck) muscle activity, were disrupted for 3–10 days after the UCO

Preterm labour and delivery occurred in a significant number of the pregnancies after UCO compared to the control (sham‐UCO) cohort.

Complications arising from antepartum events such as impaired umbilical blood flow can cause significant fetal hypoxia. These complications can be unpredictable, as well as difficult to detect, and thus we lack a detailed understanding of the (patho)physiological changes that occur between the antenatal in utero event and birth. In the present study, we assessed the consequences of brief (∼10 min) umbilical cord occlusion (UCO) in fetal sheep at ∼0.88 gestation on fetal plasma cortisol concentrations and fetal behaviour [electrocortical (EcoG), electo‐oculargram (EOG), nuchal muscle electromyography (EMG) and breathing activities] in the days following UCO. UCO caused a rapid onset of fetal hypoxaemia, hypercapnia, and acidosis; however, by 6 h, all blood parameters and cardiovascular status were normalized and not different from the control (Sham‐UCO) cohort. Subsequently, the incidence of fetal breathing movements decreased compared to the control group, and abnormal behavioural patterns developed over the days following UCO and leading up to the onset of labour, which included increased high voltage and sub‐low voltage ECoG and EOG activities, as well as decreased nuchal EMG activity. Fetuses subjected to UCO went into labour 7.9 ± 3.6 days post‐UCO (139.5 ± 3.2 days of gestation) compared to the control group fetuses at 13.6 ± 3.3 days post‐sham UCO (144 ± 2.2 days of gestation; P < 0.05), despite comparable increases in fetal plasma cortisol and a similar body weight at birth. Thus, a single transient episode of complete UCO late in gestation in fetal sheep can result in prolonged effects on fetal brain activity and premature labour, suggesting persisting effects on fetal cerebral metabolism.
Modeling Nanosecond-Pulsed Spark Discharge and Flame Kernel Evolution
Authors: Kim Joohan , Gururajan Vyaas , Scarcelli Riccardo , Biswas Sayan , Ekoto Isaac
Published: May 2021

Dilute combustion, either using exhaust gas recirculation or with excess air, is considered a promising strategy to improve the thermal efficiency of internal combustion engines. However, the dilute air-fuel mixture, especially under intensified turbulence and high-pressure conditions, poses significant challenges for ignitability and combustion stability, which may limit the attainable efficiency benefits. In-depth knowledge of the flame kernel evolution to stabilize ignition and combustion in a challenging environment is crucial for effective engine development and optimization. To date, a comprehensive understanding of ignition processes that result in the development of fully predictive ignition models usable by the automotive industry does not yet exist. Spark-ignition consists of a wide range of physics that includes electrical discharge, plasma evolution, joule-heating of gas, and flame kernel initiation and growth into a self-sustainable flame. In this study, an advanced approach is proposed to model spark-ignition energy deposition and flame kernel growth. To decouple the flame kernel growth from the electrical discharge, a nanosecond-pulsed high-voltage discharge is used to trigger spark-ignition in an optically accessible small ignition test vessel with a quiescent mixture of air and methane. Initial conditions for the flame kernel, including its thermodynamic state and species composition, are derived from a plasma-chemical equilibrium calculation. The geometric shape and dimension of the kernel are characterized using a multi-dimensional thermal plasma solver. The proposed modeling approach is evaluated using a high-fidelity computational fluid dynamics procedure to compare the simulated flame kernel evolution against flame boundaries from companion Schlieren images.
Modeling Dislocation-Mediated Hydrogen Transport and Trapping in Face-Centered Cubic Metals
Authors: Zirkle Theodore , Costello Luke , Zhu Ting , McDowell David L.
Published: May 2021

The diffusion of hydrogen in metals is of interest due to the deleterious influence of hydrogen on material ductility and fracture resistance. It is becoming increasingly clear that hydrogen transport couples significantly with dislocation activity. In this work, we use a coupled diffusion-crystal plasticity model to incorporate hydrogen transport associated with dislocation sweeping and pipe diffusion in addition to standard lattice diffusion. Moreover, we consider generation of vacancies via plastic deformation and stabilization of vacancies via trapping of hydrogen. The proposed hydrogen transport model is implemented in a physically based crystal viscoplasticity framework to model the interaction of dislocation substructure and hydrogen migration. In this study, focus is placed on hydrogen transport and trapping within the intense deformation field of a crack tip plastic zone. We discuss the implications of the model results in terms of constitutive relations that incorporate hydrogen effects on crack tip field behavior and enable exploration of hydrogen embrittlement mechanisms.
Changes in Physical Activity, Sleep, Mental Health, and Social Media Use During COVID-19 Lockdown Among Adolescent Girls: A Mixed-Methods Study
Authors: O’Kane S. Maria , Lahart Ian M. , Gallagher Alison M. , Carlin Angela , Faulkner Maria , Jago Russell , Murphy Marie H.
Published: May 2021

Background: To suppress the transmission of coronavirus, many governments, including that of the island of Ireland, implemented a societal lockdown, which included school closures, limits on social gatherings, and time outdoors. This study aimed to evaluate changes in physical activity (PA), mental health, sleep, and social media use among adolescent girls during lockdown. Methods: 281 female pupils (12–14 y) taking part in the ongoing Walking In Schools study on the island of Ireland self-reported PA, mental health, sleep, and social media use before (September–October 2019) and during lockdown (May–June 2020), via questionnaires. These were supplemented with open-ended structured interviews conducted with 16 girls during lockdown. Results: During the period of lockdown and school closures, pupils tried new forms of PA and undertook PA with family, but there was no significant change in self-reported PA. There was a decline in health-related quality of life; however, self-efficacy for walking increased. There was no change in sleep quality or social media usage. Conclusions: Despite the many challenges that schools face as they reopen, there is a need to continue to prioritize PA and motivation for exercise to support health and well-being in adolescent girls.
Development and Validation of a Burkholderia pseudomallei Core Genome Multilocus Sequence Typing Scheme To Facilitate Molecular Surveillance
Authors: Lichtenegger Sabine , Trinh Trung T. , Assig Karoline , Prior Karola , Harmsen Dag , Pesl Julian , Zauner Andrea , Lipp Michaela , Que Tram A. , Mutsam Beatrice , Kleinhappl Barbara , Steinmetz Ivo , Wagner Gabriel E.
Published: May 2021

Burkholderia pseudomallei
causes the severe disease melioidosis. Whole-genome sequencing (WGS)-based typing methods currently offer the highest resolution for molecular investigations of this genetically diverse pathogen.
Occurrence of the
p019
Gene in the
bla
KPC
-Harboring Plasmids: Adverse Clinical Impact for Direct Tracking of KPC-Producing
Klebsiella pneumoniae
by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry
Authors: Gato Eva , Constanso Ignacio Pedro , Rodiño-Janeiro Bruno Kotska , Guijarro-Sánchez Paula , Alioto Tyler , Arroyo Manuel Jesús , Méndez Gema , Mancera Luis , Gut Marta , Gut Ivo , Álvarez-Tejado Miguel , Bou Germán , Oviaño Marina
Published: May 2021

Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) has recently been used for the direct detection of KPC-producing isolates by analysis of the 11,109 Da mass peak representing the P019 protein. In this study, we evaluate the presence of the 11,109 Da mass peak in a collection of 435 unduplicated
Klebsiella pneumoniae
clinical isolates.
Draft Genome Sequence of Lignin-Degrading
Agrobacterium
sp. Strain S2, Isolated from a Decaying Oil Palm Empty Fruit Bunch
Authors: Faisal Ummu Habibah , Sabri Nurul Syazwani Ahmad , Yusof Nurtasbiyah , Tahir Analhuda Abdullah , Said Nuurul Nadrah Mohd , Riyadi Fatimah Azizah , Akhir Fazrena Nadia Md , Othman Nor’azizi , Hara Hirofumi
Published: May 2021

We report the draft genome sequence of
Agrobacterium
sp. strain S2, isolated from a decaying oil palm empty fruit bunch (OPEFB) in Negeri Sembilan, Malaysia, which yields potential genes encoding lignin degradation enzymes. This genome of 9,722,071 bp exhibited 58.9% GC content, 10,416 coding genes, and 12 RNAs.
The interfacial energy penalty to crystal growth close to equilibrium
Authors: Gaidies Fred , George Freya R.
Published: May 2021

Understanding the origin of rock microstructure is critical for refining models of the geodynamics of the Earth. We use the geometry of compositional growth zoning of a population of garnet porphyroblasts in a mica schist to gain quantitative insight into (1) the relative growth rates of individual crystals, (2) the departure from equilibrium during their growth, and (3) the mobility of the porphyroblast-matrix interface. The driving force for garnet growth in the studied sample was exceedingly small and is comparable in magnitude to the interfacial energy associated with the garnet-matrix interface. This resulted in size-dependent garnet growth at macroscopic length scales, with a decrease in radial growth rates for smaller crystals caused by the penalty effect of the interfacial energy. The difference in growth rate between the largest and the smallest crystal is ~45%, and the interface mobility for garnet growth from ~535°C, 480 MPa to 565°C, 560 MPa in the phyllosilicate-dominated rock matrix ranged between ~10−19 and 10−20 m4 J−1 s−1. This is the first estimation of interface mobility in natural rock samples. In addition to the complex structural and chemical reorganization associated with the formation of dodecahedral coordination polyhedra in garnet, the presence of abundant graphite may have exerted drag on the garnet-matrix interface, further decreasing its mobility.
Phantom vision after eye removal: prevalence, features and related risk factors
Authors: Martel Arnaud , Baillif Stephanie , Thomas Pierre , Almairac Fabien , Galatoire Olivier , Hamedani Mehrad , Fontaine Denys , Lanteri-Minet Michel
Published: May 2021

Aim

Phantom eye syndrome is a poorly understood and underestimated complication of eye removal (ER). Seeing with the amputated eye, referred to as phantom vision (PV), is undoubtedly the most intriguing and confusing complication experienced by anophthalmic patients. The aim of the study was to assess PV prevalence, clinical features and risk factors after ER.

Methods

A multicentric questionnaire-based study was conducted between April 2016 and July 2017. Patients >18 years who underwent ER >3 months ago had a socket examination before inclusion. Data recorded included patients’ demographics, and preoperative, surgical and postoperative features.

Results

One hundred patients (53 men) with a mean age of 65.1 years (29–92; SD=13.0) were included. ER indications were: uveal melanoma (n=24, 24%), trauma (n=20, 20%), retinal detachment (n=20, 20%), glaucoma (n=14, 14%) and endophthalmitis (n=12, 12%). Thirty (30%) patients experienced PV. Elementary and complex visual hallucinations were experienced by 80% and 20% of patients, respectively. PV usually appeared within the first postoperative month and tended to decrease over time. Risk factors for PV were the preoperative use of proton beam therapy (p=0.006), uveal melanoma (p=0.014), enucleation (p=0.015), anxiety with a Hospital and Anxiety Depression (HAD) score ≥8 (p=0.042), depression with a HAD score ≥8 (p=0.030), phantom eye pain (p=0.044) and phantom eye sensations (p=0.002).

Conclusion

PV was reported by one-third of our patients. Despite being widely misunderstood, ophthalmologists and neurologists should be aware of this complication to adequately reassure patients.
Development and implementation of a clinician report to reduce unnecessary urine drug screen testing in the ED: a quality improvement initiative
Authors: Vanstone Jason Robert , Patel Shivani , Degelman Michelle L , Abubakari Ibrahim W , McCann Shawn , Parker Robert , Ross Terry
Published: May 2021

Background

Unnecessary testing is a problem-facing healthcare systems around the world striving to achieve sustainable care. Despite knowing this problem exists, clinicians continue to order tests that do not contribute to patient care. Using behavioural and implementation science can help address this problem. Locally, audit and feedback are used to provide information to clinicians about their performance on relevant metrics. However, this is often done without evidence-based methods to optimise uptake. Our objective was to improve the appropriate use of laboratory tests in the ED using evidence-based audit and feedback and behaviour change techniques.

Methods

Using the behaviour change wheel, we implemented an audit and feedback tool that provided information to ED physicians about their use of laboratory tests; specifically, we focused on education and review of the appropriate use of urine drug screen tests. The report was designed in collaboration with end users to help maximise engagement. Following development of the report, audit and feedback sessions were delivered over an 18-month period.

Results

Data on urine drug screen testing were collected continually throughout the intervention period and showed a sustained decrease among ED physicians. Test use dropped from a monthly departmental average of 26 urine drug screen tests per 1000 patient visits to only eight tests per 1000 patient visits following the initiation of the audit and feedback intervention.

Conclusion

Audit and feedback reduced unnecessary urine drug screen testing in the ED. Regular feedback sessions continuously engaged physicians in the audit and feedback intervention and allowed the implementation team to react to changing priorities and feedback from the clinical group. It was important to include the end users in the design of audit and feedback tools to maximise physician engagement. Inclusion in this process can help ensure physicians adopt a sense of ownership regarding which metrics to review and provides a key component for the motivation aspect of behaviour change. Departmental leadership is also critical to the process of implementing a successful audit and feedback initiative and achieving sustained behaviour change.
Cicely Saunders, ‘Total Pain’ and emotional evidence at the end of life
Authors: Wood Joe
Published: May 2021

In this article I explore how Cicely Saunders championed the hospice movement and initiated what became palliative care by representing her emotional connections with others. She became friends (and, once or twice, fell in love) with dying patients and encouraged others to follow her example in listening to patients’ descriptions of pain. Her approach was radical at a time when she believed doctors routinely ‘deserted’ dying patients because it urged them to understand another’s embodied pain as inextricably bound up with the emotional impact of a terminal diagnosis. Saunders’ attention to how patients expressed their experience is summed up in her term ‘total pain’, which communicates how an individual’s pain is a whole overwhelming experience, not only physical but also emotional, social and spiritual. Previous research frames ‘total pain’ in terms of narrative, emphasising Saunders’ focus on listening to her patients and her use of narratives as evidence in advocating for cultural and institutional change, both of which I understand as engaging with a patient’s emotional reality. However, as Saunders’ ideals become mainstreamed as palliative care and amid calls for ‘narrative palliative care’, I use evidence from Saunders’ extensive written output alongside archival material to suggest that, just as palliative care is by its nature not a single specific intervention, ‘total pain’ should not be understood as simply narrative. Building on existing work in this journal questioning the primacy of conventional understandings of narrative in the medical humanities, I demonstrate how Saunders’ prominent use of fragments and soundbites alongside longer case narratives demonstrates the limits of narrative, particularly when someone is dying. Saunders thus offers a case study for considering the implications that questioning the primacy of narrative as emotional evidence might have for our understandings of how empathy or advocacy can function, or be cultivated, in medical settings.
An Augmented Reality Online Assistance Platform for Repair Tasks
Authors: Sun Lu , Osman Hussein Al , Lang Jochen
Published: May 2021

Our augmented reality online assistance platform enables an expert to specify 6DoF movements of a component and apply the geometrical and physical constraints in real-time. We track the real components on the expert’s side to monitor the operations of an expert. We leverage a remote rendering technique that we proposed previously to relieve the rendering burden of the augmented reality end devices. By conducting a user study, we show that the proposed method outperforms conventional instructional videos and sketches. The answers to the questionnaires show that the proposed method receives higher recommendation than sketching, and, compared to conventional instructional videos, is outstanding in terms of instruction clarity, preference, recommendation, and confidence of task completion. Moreover, as to the overall user experience, the proposed method has an advantage over the video method.
3D Tensor Auto-encoder with Application to Video Compression
Authors: Li Yang , Liu Guangcan , Sun Yubao , Liu Qingshan , Chen Shengyong
Published: May 2021

Auto-encoder has been widely used to compress high-dimensional data such as the images and videos. However, the traditional auto-encoder network needs to store a large number of parameters. Namely, when the input data is of dimension
n
, the number of parameters in an auto-encoder is in general
O
(
n
). In this article, we introduce a network structure called 3D Tensor Auto-Encoder (3DTAE). Unlike the traditional auto-encoder, in which a video is represented as a vector, our 3DTAE considers videos as 3D tensors to directly pass tensor objects through the network. The weights of each layer are represented by three small matrices, and thus the number of parameters in 3DTAE is just
O
(
n
1/3). The compact nature of 3DTAE fits well the needs of video compression. Given an ensemble of high-dimensional videos, we represent them as 3DTAE networks plus some small core tensors, and we further quantize the network parameters and the core tensors to get the final compressed data. Experimental results verify the efficiency of 3DTAE.
Integrating Scene Semantic Knowledge into Image Captioning
Authors: Wei Haiyang , Li Zhixin , Huang Feicheng , Zhang Canlong , Ma Huifang , Shi Zhongzhi
Published: May 2021

Most existing image captioning methods use only the visual information of the image to guide the generation of captions, lack the guidance of effective scene semantic information, and the current visual attention mechanism cannot adjust the focus intensity on the image. In this article, we first propose an improved visual attention model. At each timestep, we calculated the focus intensity coefficient of the attention mechanism through the context information of the model, then automatically adjusted the focus intensity of the attention mechanism through the coefficient to extract more accurate visual information. In addition, we represented the scene semantic knowledge of the image through topic words related to the image scene, then added them to the language model. We used the attention mechanism to determine the visual information and scene semantic information that the model pays attention to at each timestep and combined them to enable the model to generate more accurate and scene-specific captions. Finally, we evaluated our model on Microsoft COCO (MSCOCO) and Flickr30k standard datasets. The experimental results show that our approach generates more accurate captions and outperforms many recent advanced models in various evaluation metrics.
Biases in AI Systems
Authors: Srinivasan Ramya , Chander Ajay
Published: May 2021

This article provides an organization of various kinds of biases that can occur in the AI pipeline starting from dataset creation and problem formulation to data analysis and evaluation. It highlights the challenges associated with the design of bias-mitigation strategies, and it outlines some best practices suggested by researchers. Finally, a set of guidelines is presented that could aid ML developers in identifying potential sources of bias, as well as avoiding the introduction of unwanted biases. The work is meant to serve as an educational resource for ML developers in handling and addressing issues related to bias in AI systems.
Active Flow Control and Dynamic Analysis in Droplet Microfluidics
Authors: Shi Nan , Mohibullah Md , Easley Christopher J.
Published: May 2021

Droplet-based microfluidics has emerged as an important subfield within the microfluidic and general analytical communities. Indeed, several unique applications such as digital assay readout and single-cell sequencing now have commercial systems based on droplet microfluidics. Yet there remains room for this research area to grow. To date, most analytical readouts are optical in nature, relatively few studies have integrated sample preparation, and passive means for droplet formation and manipulation have dominated the field. Analytical scientists continue to expand capabilities by developing droplet-compatible method adaptations, for example, by interfacing to mass spectrometers or automating droplet sampling for temporally resolved analysis. In this review, we highlight recently developed fluidic control techniques and unique integrations of analytical methodology with droplet microfluidics—focusing on automation and the connections to analog/digital domains—and we conclude by offering a perspective on current challenges and future applications.
The Role of Sulfur Doping in Determining the Performance of Fe/N-C Based Electrocatalysts for Oxygen Reduction Reactions
Authors: Zhang Linlin , Hu Yongjie , Jiang Kun , Li Kai , Liu Yun-Quan , Wang Duo , Ye Yueyuan
Published: May 2021

The effect of S-doping on the performance of Fe/N-C catalysts for ORR was studied. It was found that the abundant C–S–C bonds in the sulfur-doped catalysts enhanced the ORR activity greatly, while the existence of excessive C-SOX-C bonds was adverse to the kinetics of ORR. Also, the existence of Fe was able to increase the contents of both C–S–C bond and graphite N during the pyrolysis stage of preparation, thus generating more ORR active sites. The resulted effective configurations of S (C–S–C) and active N (both graphitic N and pyridinic N), and the combination of rich hierarchical porous structure with the encased Fe3C nanoparticles were responsible for the excellent performance of catalysts. Specifically, the E1/2 of the prepared FeNSC-10S catalyst reached 0.91 V in a 0.1 M KOH electrolyte solution, which was 20 mV positive shift to the E1/2 of the 20 wt.% Pt/C commercial catalyst. The electron transfer number was determined to be 3.85−3.91 over the potential range of 0.4−0.8 V, indicating that the ORR catalytic process proceeded in a reaction pathway with nearly 4e− transfer. The developed catalyst also demonstrated a long-term stability as well as a superior methanol tolerance in alkaline conditions.
Topological reorganizations of mitochondria isolated from rat brain after 72 hours of paradoxical sleep deprivation, revealed by electron cryo-tomography
Authors: Lu Zhuoyang , Hu Yachong , Wang Yongyao , Zhang Tiantian , Long Jiangang , Liu Jiankang
Published: May 2021

Sleep deprivation has profound influence on several aspects of health and disease. Mitochondria dysfunction has been implicated to play an essential role in the neuronal cellular damage induced by sleep deprivation, but little is known about how neuronal mitochondrial ultrastructure is affected under sleep deprivation. In this report, we utilized electron cryo-tomography to reconstruct the three-dimensional (3-D) mitochondrial structure and extracted morphometric parameters to quantitatively characterize its reorganizations. Isolated mitochondria from the hippocampus and cerebral cortex of adult male Sprague–Dawley rats after 72 h of paradoxical sleep deprivation (PSD) were reconstructed and analyzed. Statistical analysis of six morphometric parameters specific to the mitochondrial inner membrane topology revealed identical pattern of changes in both the hippocampus and cerebral cortex but with higher significance levels in the hippocampus. The structural differences were indistinguishable by conventional phenotypic methods based on two-dimensional electron microscopy images or 3-D electron tomography reconstructions. Furthermore, to correlate structure alterations with mitochondrial functions, high-resolution respirometry was employed to investigate the effects of PSD on mitochondrial respiration, which showed that PSD significantly suppressed the mitochondrial respiratory capacity of the hippocampus, whereas the isolated mitochondria from the cerebral cortex were less affected. These results demonstrate the capability of the morphometric parameters for quantifying complex structural reorganizations and suggest a correlation between PSD and inner membrane architecture/respiratory functions of the brain mitochondria with variable effects in different brain regions.
Mechanics of dystrophin deficient skeletal muscles in very young mice and effects of age
Authors: Lopez Michael A. , Bontiff Sherina , Adeyeye Mary , Shaibani Aziz I. , Alexander Matthew S. , Wynd Shari , Boriek Aladin M.
Published: May 2021

The MDX mouse is an animal model of Duchenne muscular dystrophy, a human disease marked by an absence of the cytoskeletal protein, dystrophin. We hypothesized that 1) dystrophin serves a complex mechanical role in skeletal muscles by contributing to passive compliance, viscoelastic properties, and contractile force production and 2) age is a modulator of passive mechanics of skeletal muscles of the MDX mouse. Using an in vitro biaxial mechanical testing apparatus, we measured passive length-tension relationships in the muscle fiber direction as well as transverse to the fibers, viscoelastic stress-relaxation curves, and isometric contractile properties. To avoid confounding secondary effects of muscle necrosis, inflammation, and fibrosis, we used very young 3-wk-old mice whose muscles reflected the prefibrotic and prenecrotic state. Compared with controls, 1) muscle extensibility and compliance were greater in both along fiber direction and transverse to fiber direction in MDX mice and 2) the relaxed elastic modulus was greater in dystrophin-deficient diaphragms. Furthermore, isometric contractile muscle stress was reduced in the presence and absence of transverse fiber passive stress. We also examined the effect of age on the diaphragm length-tension relationships and found that diaphragm muscles from 9-mo-old MDX mice were significantly less compliant and less extensible than those of muscles from very young MDX mice. Our data suggest that the age of the MDX mouse is a determinant of the passive mechanics of the diaphragm; in the prefibrotic/prenecrotic stage, muscle extensibility and compliance, as well as viscoelasticity, and muscle contractility are altered by loss of dystrophin.
Sympathetic activation due to limb venous distension is preserved during muscle metaboreceptor stimulation
Authors: Cui Jian , Blaha Cheryl , Leuenberger Urs A. , Sinoway Lawrence I.
Published: May 2021

Venous saline infusions in an arterially occluded forearm evoke reflex increases in muscle sympathetic nerve activity (MSNA) and blood pressure (BP) in humans (venous distension reflex). It is unclear if the inputs from metabolically sensitive skeletal muscle afferents (i.e., muscle metaboreflex) would modify the venous distension reflex. We hypothesized that muscle metaboreceptor stimulation might augment the venous distension reflex. BP (Finapres), heart rate (ECG), and MSNA (microneurography) were assessed in 18 young healthy subjects. In trial A, saline (5% forearm volume) was infused into the veins of an arterially occluded arm (nonhandgrip trial). In trial B, subjects performed 2-min static handgrip followed by postexercise circulatory occlusion (PECO) of the arm. During PECO, saline was infused into the veins of the arm (handgrip trial). In trial A, the infusion increased MSNA and BP as expected (both P < 0.001). In trial B, handgrip significantly raised MSNA, BP, and venous lactic acid concentrations. Venous saline infusion during PECO further raised MSNA and BP (both P < 0.001). The changes in MSNA (Δ8.6 ± 1.5 to Δ10.6 ± 1.8 bursts/min, P = 0.258) and mean arterial pressure ( P = 0.844) evoked by the infusion during PECO were not significantly different from those in the nonhandgrip trial. These observations indicate that venous distension reflex responses are preserved during sympathetic activation mediated by the muscle metaboreflex.
New roles for dopamine in motor skill acquisition: lessons from primates, rodents, and songbirds
Authors: Wood A. N.
Published: May 2021

Motor learning is a core aspect of human life and appears to be ubiquitous throughout the animal kingdom. Dopamine, a neuromodulator with a multifaceted role in synaptic plasticity, may be a key signaling molecule for motor skill learning. Though typically studied in the context of reward-based associative learning, dopamine appears to be necessary for some types of motor learning. Mesencephalic dopamine structures are highly conserved among vertebrates, as are some of their primary targets within the basal ganglia, a subcortical circuit important for motor learning and motor control. With a focus on the benefits of cross-species comparisons, this review examines how “model-free” and “model-based” computational frameworks for understanding dopamine’s role in associative learning may be applied to motor learning. The hypotheses that dopamine could drive motor learning either by functioning as a reward prediction error, through passive facilitating of normal basal ganglia activity, or through other mechanisms are examined in light of new studies using humans, rodents, and songbirds. Additionally, new paradigms that could enhance our understanding of dopamine’s role in motor learning by bridging the gap between the theoretical literature on motor learning in humans and other species are discussed.
Predictive Maintenance and Sensitivity Analysis for Equipment with Multiple Quality States
Authors: Wang Xiao , Xu Deyi , Qu Na , Liu Tianqi , Qu Fang , Zhang Guowei
Published: May 2021

This paper discusses the predictive maintenance (PM) problem of a single equipment system. It is assumed that the equipment has deteriorating quality states as it operates, resulting in multiple yield levels represented as system observation states. We cast the equipment deterioration as discrete-state and continuous-time semi-Markov decision process (SMDP) model and solve the SMDP problem in reinforcement learning (RL) framework using the strategy-based method. In doing so, the goal is to maximize the system average reward rate (SARR) and generate the optimal maintenance strategy for given observation states. Further, the PM time is capable of being produced by a simulation method. In order to prove the advantage of our proposed method, we introduce the standard sequential preventive maintenance algorithm with unequal time interval. Our proposed method is compared with the sequential preventive maintenance algorithm in a test objective of SARR, and the results tell us that our proposed method can outperform the sequential preventive maintenance algorithm. In the end, the sensitivity analysis of some parameters on the PM time is given.
Identification of Hub Genes to Regulate Breast Cancer Spinal Metastases by Bioinformatics Analyses
Authors: He Yongxiong , Cao Yongfei , Wang Xiaolei , Jisiguleng Wu , Tao Mingkai , Liu Jianfeng , Wang Fei , Chao Lemeng , Wang Wenjun , Li Pengfei , Fu Haiping , Xing Wei , Zhu Zhibo , Huan Yanqiang , Yuan Hongwei
Published: May 2021

Breast cancer (BC) had been one of the deadliest types of cancers in women worldwide. More than 65% of advanced-stage BC patients were identified to have bone metastasis. However, the molecular mechanisms involved in the BC spinal metastases remained largely unclear. This study screened dysregulated genes in the progression of BC spinal metastases by analyzing GSE22358. Moreover, we constructed PPI networks to identify key regulators in this progression. Bioinformatics analysis showed that these key regulators were involved in regulating the metabolic process, cell proliferation, Toll-like receptor and RIG-I-like receptor signaling, and mRNA surveillance. Furthermore, our analysis revealed that key regulators, including C1QB, CEP55, HIST1H2BO, IFI6, KIAA0101, PBK, SPAG5, SPP1, DCN, FZD7, KRT5, and TGFBR3, were correlated to the OS time in BC patients. In addition, we analyzed TCGA database to further confirm the expression levels of these hub genes in breast cancer. Our results showed that these regulators were significantly differentially expressed in breast cancer, which were consistent with GSE22358 dataset analysis. Furthermore, our analysis demonstrated that CEP55 was remarkably upregulated in the advanced stage of breast cancer compared to the stage I breast cancer sample and was significantly upregulated in triple-negative breast cancers (TNBC) compared to other types of breast cancers, including luminal and HER2-positive cancers, demonstrating CEP55 may have a regulatory role in TNBC. Finally, our results showed that CEP55 was the most highly expressed in Basal-like 1 TNBC and Basal-like 2 TNBC samples but the most lowly expressed in mesenchymal stem-like TNBC samples. Although more studies are still needed to understand the functions of key regulators in BC, this study provides useful information to understand the mechanisms underlying BC spinal metastases.
Surrounding Rock Movement of Steeply Dipping Coal Seam Using Backfill Mining
Authors: Lv Wenyu , Guo Kai , Yu Jianhao , Du Xufeng , Feng Kun
Published: May 2021

The movement of the overlying strata in steeply dipping coal seams is complex, and the deformation of roof rock beam is obvious. In general, the backfill mining method can improve the stability of the surrounding rock effectively. In this study, the 645 working face of the tested mine is used as a prototype to establish the mechanical model of the inclined roof beam using the sloping flexible shield support backfilling method in a steeply dipping coal seam, and the deflection equation is derived to obtain the roof damage structure and the maximum deflection position of the roof beam. Finally, numerical simulation and physical similarity simulation experiments are carried out to study the stability of the surrounding rock structure under backfilling mining in steeply dipping coal seams. The results show the following: (1) With the support of the gangue filling body, the inclined roof beam has smaller roof subsidence, and the maximum deflection position moves to the upper part of working face. (2) With the increase of the stope height, the stress and displacement field of the surrounding rock using the backfilling method show an asymmetrical distribution, the movement, deformation, and failure increase slowly, and the increase of the strain is relatively stable. Compared with the caving method, the range and degree of the surrounding rock disturbed by the mining stress are lower. The results of numerical simulation and physical similarity simulation experiment are generally consistent with the theoretically derived results. Overall, this study can provide theoretical basis for the safe and efficient production of steeply dipping coal seams.
Study on Viscosity Reducer Flooding Technology for Deep Low Permeability Extra Heavy Oil Reservoirs
Authors: Cao Xiaopeng , Liu Zupeng , Yang Yong , Zhang Shiming , Bu Yahui , Wang Sen , Liang Yipu , Feng Qihong
Published: May 2021

Deep low permeability extra heavy oil reservoir has the characteristics of high formation pressure, high crude oil viscosity, and low permeability. Conventional steam injection thermal recovery has poor viscosity reduction performance and low productivity of a single well, which makes it difficult to develop this type of heavy oil reservoir. In this paper, core flooding experiment and microvisualization equipment were used to study the mechanism of improving the recovery of deep extra heavy oil by using water-soluble viscosity reducer; the realization of water-soluble viscosity reducer in numerical simulation was achieved by using nonlinear mixing rule; the reservoir numerical simulation model of water-soluble viscosity reducer displacement in test well group was established to optimize the development technical parameter of water-soluble viscosity reducer. The results show that compared with waterflooding, the oil displacement efficiency of water-soluble viscosity reducer is increased by 12.7%; water-soluble viscosity reducer can effectively reduce the viscosity of extra heavy oil, under the same temperature and permeability, the higher the concentration of viscosity reducer, the better the viscosity reduction effect, and the smaller the pressure gradient required at the same injection rate; the main mechanism of water-soluble viscosity reducer for enhancing oil recovery is to form oil in water emulsion, which can reduce the viscosity and interfacial tension of crude oil and reduce the residual oil saturation; in the pilot well group, the optimized injection concentration of water-soluble viscosity reducer is 3%, and the optimal injection amount of water-soluble viscosity reducer solution is 50 t/d; water-soluble viscosity reducer displacement was implemented in the pilot well group, the average daily oil of well group was increased from 1.8 t/d to 7.34 t/d, and the pilot well group has achieved good development performance.
A Moving Target Tracking Control of Quadrotor UAV Based on Passive Control and Super-Twisting Sliding Mode Control
Authors: Xue Wentao , Zhu Xunnan , Yang Xiaofei , Ye Hui , Chen Xuan
Published: May 2021

A novel asymptotic tracking controller for an underactuated quadrotor unmanned aerial vehicle (UAV) is proposed to solve a moving target tracking problem. Firstly, the control system is decoupled into the position control system and the attitude control system. Secondly, a method combined artificial potential field with passivity control (APF&PC) is introduced for the positioning system to achieve high-precision tracking of moving target at a fixed distance. Thirdly, a super-twisting sliding mode (STSM) method with an improved reaching law for the attitude system is applied to ensure that the attitude converges to the desired value. Furthermore, the stabilities of two subsystems are proved, and sufficient stability conditions are derived based on the passive method and Lyapunov method, respectively. Finally, simulation results of the moving target tracking verify the superiority and robustness of the proposed control method in the presence of parameter uncertainties and external disturbances.
A Robust Estimate Method for Damage Detection of Concrete Structures Using Contaminated Data
Authors: Peng X. , Qin F. J. , Yang Q. W. , Chen H.
Published: May 2021

Damage detection of concrete structures based on finite element model and measured response parameters has been an important research topic in recent years. It is well known that test data of mechanical behavior of concrete show great scatterness. As a result, the measured response parameters of concrete structures sometimes have gross errors. The gross error is a physical quantity that is much larger than data noise, which may lead to serious distortion of calculation results. To this end, a new robust estimate method termed as the augmented inverse estimate is proposed in this work for damage detection of concrete structures to resist gross errors in data. It has the advantages of very simple programming, convenient utilization, high computational accuracy, and broad prospect of application. Central to the augmented inverse estimate are the augmentation of coefficient matrix and the multiple computations based on feedback evaluation. A reinforced concrete beam structure is used as an example to verify the proposed method. It was found that the proposed method can successfully identify the location and extent of structural damage even if the used data have gross errors.
Pyrolysis and Morphology Behavior of EDTA-Na2Mg•4H2O and Coal Tar Pitch and Its Application for Porous Carbon
Authors: Zhang Wen-Juan , Song Shi-Hua , Tian Wen-Hong
Published: May 2021

Coal tar pitch (CTP) is a quite promising candidate for the production of porous carbons. Traditionally, the porous carbons are prepared by the heat treatment of carbon precursors in the presence of template and activator. In this paper, EDTA-Na2Mg•4H2O and CTP were mixed to produce porous carbons in the absence of template and activator, which were generated in situ by the heat treatment of EDTA-Na2Mg•4H2O. The pyrolysis and morphology behavior of the mixture of EDTA-Na2Mg•4H2O and coal tar pitch (EDTA-Na2Mg•4H2O@CTP) were studied by thermogravimetry and differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The characteristics of the obtained porous carbons were characterized by N2 adsorption-desorption isotherm. The results show that EDTA-Na2Mg•4H2O has a great influence on the pyrolysis and morphology of CTP. The pyrolysis behavior of CTP becomes complicated after the addition of EDTA-Na2Mg•4H2O for the physical and chemical changes of EDTA-Na2Mg•4H2O during the heat treatment. EDTA-Na2Mg•4H2O@CTP dehydrates at 160°C and decomposes Na2CO3 and MgO at 600°C. The surface morphology of EDTA-Na2Mg•4H2O@CTP changes with the EDTA-Na2Mg•4H2O content and heat treatment temperature. After acid washing of the product of EDTA-Na2Mg•4H2O@CTP heat-treated at 700°C, the obtained porous carbon material consists of micropores and mesopores. Its specific surface area is 574.18 m2 g−1 and the average pore width is 4.53 nm.
Posterior Reversible Encephalopathy Syndrome (PRES) and Drug-Induced Hypersensitivity Syndrome (DIHS) following Immunotherapy and BRAF/MEK Inhibition with Continued Response in Metastatic Melanoma
Authors: Sabile J. M. , Grider D. J. , Prickett K. A. , Li H. , Mallidi P. V.
Published: May 2021

Background. The role of immunotherapy continues to evolve across both solid and hematologic malignancies. However, while use of immunotherapy has increased via the advent of checkpoint inhibition, chimeric antigen receptors, and vaccines against malignant cells, there remains uncertainty regarding the recognition and management of delayed immune-related reactions and post treatment immune-related sensitivity to subsequent medications, such as BRAF/MEK kinase inhibitors. Furthermore, it is unclear how immunotherapy may alter the adverse effect profile and efficacy of subsequent lines of treatment. Case Presentation. Discussed is a patient with stage IV metastatic melanoma who failed first-line treatment with a combination of nivolumab and ipilimumab. He was then treated with BRAF/MEK kinase inhibition via Encorafenib and Binimetinib. Shortly thereafter, the patient developed posterior reversible encephalopathy syndrome (PRES) and a generalized pruritic rash that was biopsied with consideration toward drug reaction versus drug-induced hypersensitivity syndrome (DIHS), formerly called drug reaction with eosinophilia and systemic symptoms (DRESS). The BRAF/MEK combination was held and steroid taper initiated with continued response even beyond conclusion of the steroid taper. Discussion and Conclusions. This case highlights the diagnostic challenge presented by PRES and DIHS in the setting of immunotherapy and BRAF/MEK kinase inhibition for malignant melanoma. The clinical rationale for reinitiating therapy following severe immune reactions subsequent to immunotherapy in the setting of relapsed/refractory metastatic melanoma is discussed. Additionally, the durable response our patient experienced throughout the drug hold period and steroid taper and its clinical potential etiologies and applications are reviewed. As checkpoint inhibition and tyrosine-kinase inhibitors have become cornerstones of cancer therapy, larger studies and long-term observations are needed to investigate the risks and benefits across different sequences of therapy.
Expression EEG Multimodal Emotion Recognition Method Based on the Bidirectional LSTM and Attention Mechanism
Authors: Zhao Yifeng , Chen Deyun
Published: May 2021

Due to the complexity of human emotions, there are some similarities between different emotion features. The existing emotion recognition method has the problems of difficulty of character extraction and low accuracy, so the bidirectional LSTM and attention mechanism based on the expression EEG multimodal emotion recognition method are proposed. Firstly, facial expression features are extracted based on the bilinear convolution network (BCN), and EEG signals are transformed into three groups of frequency band image sequences, and BCN is used to fuse the image features to obtain the multimodal emotion features of expression EEG. Then, through the LSTM with the attention mechanism, important data is extracted in the process of timing modeling, which effectively avoids the randomness or blindness of sampling methods. Finally, a feature fusion network with a three-layer bidirectional LSTM structure is designed to fuse the expression and EEG features, which is helpful to improve the accuracy of emotion recognition. On the MAHNOB-HCI and DEAP datasets, the proposed method is tested based on the MATLAB simulation platform. Experimental results show that the attention mechanism can enhance the visual effect of the image, and compared with other methods, the proposed method can extract emotion features from expressions and EEG signals more effectively, and the accuracy of emotion recognition is higher.