bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation on Snap-Through Buckling Behavior of Dished Shells Under Uniform External Pressure
Authors: Tripathi Surya Mani , Swain Digendranath , Muthukumar R. , Anup S.
Published: August 2020

Previously, the buckling behavior of several conical and spherical shells have been studied with great rigor. In this paper, snap-through buckling behavior for metallic dished shells under uniform external pressure is investigated. These shells are geometrically complex since they consist of a shallow conical frustum with a flat closed top. Such shells find many engineering applications, for instance as actuator elements in control components in cryogenic engines. Currently, no clear guidelines exist for design performance evaluation of such peculiar shells. This paper aims to establish a valid FE methodology for snap-through buckling and post-buckling analysis of such shells using abaqus in tandem with experiments. A parametric study is carried out to understand the effect of geometrical parameters and imperfection sensitivity of these shells to snap-through buckling. Moreover, experiments were carried out using 3D Digital Image Correlation (3D-DIC) for measuring whole-field deflection and strains. Numerical analysis was carried out, using generalized Eigen value analysis and non-linear analysis using a modified-Riks technique with various material models to correlate with the experimental observations. Non-linear elasto-plastic analysis with a perfectly elastic-plastic material model agrees well with the experimental observations. A comparison of experimental results with that of the numerical study indicates that material plasticity has a major effect on critical buckling pressure.
An Ontology-Based Framework for Decision Support in Assembly Variant Design
Authors: Das Shantanu Kumar , Swain Abinash Kumar
Published: August 2020

The designer generates a variant product by applying several design suggestions that fulfilled a variety of customer requirements. These design suggestions rely on multiple domains of expert knowledge, which are unstructured and implicit. Moreover, these design suggestions have an impact on assembly joint information (liaison), which makes the variant design a complex problem. To effectively support the designers, this work presents a knowledge-based decision support system for assembly variant design using ontology. First, a knowledge base is built by the development of an ontology to formally represent the taxonomy, properties, and causal relationships of/among core concepts involved in the variant design. Second, a five-step sequential procedure is established to facilitate the utilization of this knowledge base for decision-making in variant design. The procedure takes the extracted liaison information from the CAD model of an existing product as the input and further used for generating a set of variant design decisions as the output through Semantic Web Rule Language (SWRL) rule-based reasoning. The inferred outputs by the process of reasoning are the design suggestions, the variant design type required for each design suggestion, and its effect on joint information. Based on the evaluation of the ontology, the precision, recall, and F-measure obtained are 79.3%, 82.1%, and 80.67%, respectively. Finally, the efficacy of the knowledge-based decision support system is evaluated using case studies from the aerospace and automotive domain.
Compound Droplet Modeling for Circulating Tumor Cell Microfiltration With Adaptive Meshing Refinement
Authors: Hashem Mohammad Abul , Aghilinejad Arian , Chen Xiaolin , Tan Hua
Published: August 2020

Advances in microfluidics inaugurate a new possibility of designing diagnostic devices for early cancer detection. There is a growing interest in deformation-based microfiltration for capturing circulating tumor cells (CTCs) from peripheral blood due to its simplicity and low cost. Fundamental understanding of CTC passing through a microfilter is critical, as it helps optimize the design for achieving high isolation purity. Previous research has modeled CTC as a simple droplet for deformation-based CTC separation. Here, we use a compound droplet model to study the flow dynamics more realistically. An adaptive-mesh-refinement (AMR) method is used here, using the open-source code, gerris, after modification for droplet dynamics and contact angle model. The developed code is validated with results compared with ansysfluent and available theory. The effects of various parameters such as the nuclear-to-cytoplasmic (N/C) ratio, operating flow rate, and cell viscosity are investigated. It is found that the compound droplet behaves like a homogeneous droplet when the nucleus size is smaller than the filtering channel. However, the pressure profile is greatly influenced by the nucleus when it is larger than the channel size. In addition, there is a linear correlation between the pressure drop in the channel and the operating flow rate. Similarly, critical passing pressure increases linearly with the increase of the cell viscosity. Our study suggests that for having an accurate prediction of cell transport behavior inside the microchannel, it is of great importance to consider the effects of the nucleus and its possible deformation.
Development of Analytical Solution for a Two-Phase Stefan Problem in Artificial Ground Freezing Using Singular Perturbation Theory
Authors: Xu Minghan , Akhtar Saad , Zueter Ahmad F. , Auger Victor , Alzoubi Mahmoud A. , Sasmito Agus P.
Published: August 2020

Artificial ground freezing (AGF) has historically been used to stabilize underground structure. Numerical methods generally require high computational power to be applicable in practice. Therefore, it is of interest to develop accurate and reliable analytical frameworks for minimizing computational cost. This paper proposes a singular perturbation solution for a two-phase Stefan problem that describes outward solidification in AGF. Specifically, the singular perturbation method separates two distinct temporal scales to capture the subcooling and freezing stages in the ground. The ground was considered as a porous medium with volume-averaged thermophysical properties. Further, Stefan number was assumed to be small, and effects of a few site-dependent parameters were investigated. The analytical solution was verified by numerical results and found to have similar conclusions yet with much lesser computational cost.

Keywords: artificial ground freezing, Stefan-like problems, singular perturbation, porous media, outward solidification.
Study on Sloshing Effect of Vertical Storage Tank With Displacement Seismic Excitation
Authors: Cui Lifu , Sun Jiangang , Liu Weibing , Wang Zhen , Li Xiang
Published: August 2020

A 1:4 scale seismic simulation shaking table experiment was designed and performed to study the sloshing wave height response of a storage tank under displacement due to seismic excitation, wherein a 1000 m3 vertical storage tank was used to compare the sloshing wave height for different tanks with different foundations. Under different foundation forms, the tank motion includes sway and roll. Meanwhile, the design code and finite element method were used to compare with the experiment for mutual verification. The results show that the peak value of the sloshing wave height is at its minimum at the center, and the maximum is near the tank wall when the model tank was excited to the ground motion with the predominant frequency range from 0.29 and 0.32 Hz, and the floating roof can significantly reduce the sloshing wave height. For different input conditions with equivalent seismic magnitude, the wave heights were notably different, so the design should use multiple seismic waves as inputs. The acceleration values were different when different foundations were used, but there was little effect on the sloshing wave height. Besides, the sloshing wave heights measured in the experiment were close to those calculated using standard equations and finite element results, which proves that the three can verify each other.
Experimental Study of the Hydraulic Performances of Two Three-Bladed Inducers in Water, Water With Dissolved CO2, and Jet Fuel
Authors: Magne Théodore , Paridaens Richard , Khelladi Sofiane , Bakir Farid , Tomov Petar , Pora Loic
Published: August 2020

Inducers in centrifugal pumps are generally placed upstream to increase the pressure before the impeller and prevent cavitation occurrence. Their general goal is to obtain a positive impact on the performances of a pump in a two-phase regime. Cavitation phenomenon has been the subject of many studies; however, the influence of the presence of dissolved gas in the liquid pumped under particular operating conditions remains not sufficiently explored. To the best of our knowledge, aviation jet fuel cavitation is moderately documented. In the present work, we conducted an experimental study on two three-bladed axial inducers at partial flow rates only in cavitating and noncavitating regimes. The experimental work used aviation jet fuel, water, and water with dissolved content of CO2 at constant temperature in two closed loops with transparent test sections. In one tank, a specific device is placed to inject a controlled quantity of CO2 and to dissolve it in water. We achieved a comparison of the flow dynamics through the use of a high-speed camera with a sampling rate of 1000 Hz. The results show inducers' water–CO2 cavitation performances to be in good agreement with aviation jet fuel cavitation results.
Experimental Flow-Induced Motions of a FOWT Semi-Submersible Type (OC4 Phase II Floater)
Authors: Gonçalves Rodolfo T. , Chame Maria E. F. , Silva Leandro S. P. , Koop Arjen , Hirabayashi Shinichiro , Suzuki Hideyuki
Published: August 2020

Flow-induced motions (FIM) are an issue for floating offshore structures, such as multi-column platforms, as the phenomenon can decrease the fatigue life of the mooring, riser, and cable systems. The new concept of floating offshore wind turbines (FOWT) have a multi-column design that may be subjected to FIM. In the past, FIM was studied mainly for Oil & Gas platforms installed in deep waters. However, the FIM phenomenon of FOWT has been insufficiently explored. To rectify this, model tests were performed for the semisubmersible (SS) floating system design developed for the DeepCwind project (Offshore Code Comparison Collaboration Continuation (OC4) phase II). This paper will investigate the presence of FIM and show its importance in the design process of FOWT. Three different incidence angles of the current were tested, namely, 0, 90, and 180 deg. For each heading, 30 reduced velocities were tested, across the range 8000 < Re < 70,000. The results showed amplitudes in the transverse direction of around 70% of the diameter of the platform column, which is similar to those observed for deep-draft (DD) SS with circular columns. Note that these amplitude values are larger for a floater with a circular column, than for a platform with square columns. The results showed that as FIM occurred for this specific FOWT SS, its effect has to be considered in the mooring system and electric cable design.
Elastography of the uterine cervix in gynecology: normal appearance, cervical intraepithelial neoplasia and cancer. A systematic review
Authors: Dudea-Simon Marina , Dudea Sorin Marian , Ciortea Razvan , Malutan Andrei , Mihu Dan
Published: August 2020

Aims: To revise the current literature about the usefulness of elastography in cervical cancer (CC) and cervical intraepithelial neoplasia (CIN), from methods and technical limitations, to diagnosis, staging and the ability of predicting the response to oncologic treatment.Methods: An electronic database search was performed (PubMed, EMBASE, Web of Science) with the data range from January 2000 until May 2020. All studies, fully-available in English, assessing elastography of the uterine cervix in CC and CIN were selected. Studies were reviewed and discussed according to the elastographic technique and to the purpose of the research.Results: Twenty-three articles were found: 11 articles regarding strain elastography, 4 articles assessing shear wave elastography and 8 papers with matter-related information. Elastography was used in the study of normal variants of the uterine cervix as well as: the positive diagnosis of CC and CIN, clinical staging and the prediction of therapeutic response in CC. Comparison of the elastographic techniques was also performed.Conclusions: Elastography has multiple applications in the gynecological pathology of the cervix. The methods used to assess the cervix are diverse, and none have become universally accepted. With regard to CC and CIN, elastography is still an ongoing research field.
Speech variability: A cross-language study on acoustic variations of speaking versus untrained singing
Authors: Hansen John H. L. , Bokshi Marigona , Khorram Soheil
Published: August 2020

Speech production variability introduces significant challenges for existing speech technologies such as speaker identification (SID), speaker diarization, speech recognition, and language identification (ID). There has been limited research analyzing changes in acoustic characteristics for speech produced by untrained singing versus speaking. To better understand changes in speech production of the untrained singing voice, this study presents the first cross-language comparison between normal speaking and untrained karaoke singing of the same text content. Previous studies comparing professional singing versus speaking have shown deviations in both prosodic and spectral features. Some investigations also considered assigning the intrinsic activity of the singing. Motivated by these studies, a series of experiments to investigate both prosodic and spectral variations of untrained karaoke singers for three languages, American English, Hindi, and Farsi, are considered. A comprehensive comparison on common prosodic features, including phoneme duration, mean fundamental frequency (F0), and formant center frequencies of vowels was performed. Collective changes in the corresponding overall acoustic spaces based on the Kullback-Leibler distance using Gaussian probability distribution models trained on spectral features were analyzed. Finally, these models were used in a Gausian mixture model with universal background model SID evaluation to quantify speaker changes between speaking and singing when the audio text content is the same. The experiments showed that many acoustic characteristics of untrained singing are considerably different from speaking when the text content is the same. It is suggested that these results would help advance automatic speech production normalization/compensation to improve performance of speech processing applications (e.g., speaker ID, speech recognition, and language ID).
Elicitation context does not drive F0 lowering following voiced stops: Evidence from French and Italian
Authors: Kirby James , Robert Ladd D. , Gao Jiayin , Elliott Zuzana
Published: August 2020

Consonant-intrinsic F0 (CF0) effects are mainly the result of raising F0 following voiceless obstruents, rather than of lowering F0 following voiced obstruents. However, there are also documented instances where lowered F0 following voiced obstruents is enhanced. Given that both voicing and F0 are affected by prosodic context, it is possible that CF0 is lowered in some contexts but not others. This possibility is investigated by examining CF0 in French and Italian in isolated citation forms. Results are comparable to carrier-phrase contexts, where no F0 lowering after voiced obstruents is observed. Possible sources of the apparent cross-linguistic differences are discussed.
Frequency- and depth-dependent target strength measurements of individual mesopelagic scatterers
Authors: Bassett Christopher , Lavery Andone C. , Stanton Timothy K. , Cotter Emma DeWitt
Published: August 2020

Recent estimates based on shipboard echosounders suggest that 50% or more of global fish biomass may reside in the mesopelagic zone (depths of ∼200–1000 m). Nonetheless, little is known about the acoustic target strengths (TS) of mesopelagic animals because ship-based measurements cannot resolve individual targets. As a result, biomass estimates of mesopelagic organisms are poorly constrained. Using an instrumented tow-body, broadband (18–90 kHz) TS measurements were obtained at depths from 70 to 850 m. A comparison between TS measurements at-depth and values used in a recent global estimate of mesopelagic biomass suggests lower target densities at most depths.
Pandemic hits scientist parents hard
Authors: Langin Katie
Published: August 2020

New data quantify lost work hours and productivity.
Trump directive on state counts said to threaten rigor of census
Authors: Mervis Jeffrey
Published: August 2020

Experts decry order to exclude undocumented residents.
Siberia's ‘gateway to the underworld’ hit by heat wave
Authors: Stone Richard
Published: August 2020

Thawing Batagay permafrost holds deep climate history.
For science in Latin America, ‘a fascinating challenge’
Authors: Ortega Rodrigo Pérez , Wessel Lindzi
Published: August 2020

Pandemic shows benefits of investments in research but also poses grave threats.
Don't crush that ant—it could plant a wildflower
Authors: Pennisi Elizabeth
Published: August 2020

New findings show how ants choose and protect the seeds they disperse.
Lucky strike
Authors: Sokol Joshua
Published: August 2020

Last year, an unusual meteorite crashed in a Costa Rican rainforest. Rich in the building blocks of life, it has captivated collectors and researchers.
Trophic pyramids reorganize when food web architecture fails to adjust to ocean change
Authors: Nagelkerken Ivan , Goldenberg Silvan U. , Ferreira Camilo M. , Ullah Hadayet , Connell Sean D.
Published: August 2020

Inflexible webs

It is clear that human activities are negatively affecting current ecosystems. Predicting how our activities will affect future systems is more challenging because it involves estimating the unknown. Nagelkerken
et al.
overcame some of these unknowns by constructing small versions, or mesocosms, of a marine ecosystem that included species representing all trophic levels (see the Perspective by Chown). They then exposed these systems to predicted future levels of carbon dioxide and acidification. The trophic structure was relatively resistant to acidification but not to warming. Warmed systems experienced a reorganization of trophic structure that was not rescued by functional redundancy or other stabilizing responses. Such inflexibility may be a precursor of ecosystem collapse.

Science
, this issue p.
829
; see also p.
770
Active restoration accelerates the carbon recovery of human-modified tropical forests
Authors: Philipson Christopher D. , Cutler Mark E. J. , Brodrick Philip G. , Asner Gregory P. , Boyd Doreen S. , Moura Costa Pedro , Fiddes Joel , Foody Giles M. , van der Heijden Geertje M. F. , Ledo Alicia , Lincoln Philippa R. , Margrove James A. , Martin Roberta E. , Milne Sol , Pinard Michelle A. , Reynolds Glen , Snoep Martijn , Tangki Hamzah , Sau Wai Yap , Wheeler Charlotte E. , Burslem David F. R. P.
Published: August 2020

The carbon gain in restored logged forest

There is currently great interest in the capacity of global forest to store carbon and hence contribute to the mitigation of climate change in the coming decades. In a study of Southeast Asian tropical forest, Philipson
et al.
show that active restoration of logged forests generates higher rates of carbon accumulation than naturally regenerating forest. To estimate the economic feasibility of restoration treatments, they modeled the carbon price required to offset the cost of restoration, finding that the highest prices seen in recent years would be needed to approach those that could offset restoration costs. These results are important for tropical forest policy, establishing the importance of restoration for the carbon recovery potential of tropical forests.

Science
, this issue p.
838
Divergent synthesis of complex diterpenes through a hybrid oxidative approach
Authors: Zhang Xiao , King-Smith Emma , Dong Liao-Bin , Yang Li-Cheng , Rudolf Jeffrey D. , Shen Ben , Renata Hans
Published: August 2020

Trio of enzymes power divergent synthesis

Diterpene natural products are built from a 20-carbon building block, with a huge range of possible structures and modifications. Chemical synthesis of specific molecules, some of which have valuable biological activities, is tricky because of the need for selective oxidations and rearrangements when starting from widely available scaffolds. Zhang
et al.
characterized selectivities for three oxidative enzymes that each attack different positions on a common scaffold. They then seamlessly combined chemical transformations with the enzymatic oxidations to produce nine distinct compounds across three families of diterpenes. These results highlight the potential of hybrid organic-biocatalytic synthetic schemes for divergent synthesis.

Science
, this issue p.
799
Designing a wider superelastic window
Authors: La Roca Paulo , Sade Marcos
Published: August 2020

Adding chromium to an iron alloy enables shape recovery over a wide temperature range
Chimeric plants—the best of both worlds
Authors: McCann Maureen C.
Published: August 2020

Overcoming graft incompatibility between species could protect future crop yields
Michael Soulé (1936–2020)
Authors: Inouye David W. , Ehrlich Paul R.
Published: August 2020

Founder of conservation biology
Population Pharmacokinetics of Cycloserine and Pharmacokinetic/Pharmacodynamic Target Attainment in Multidrug-Resistant Tuberculosis Patients Dosed with Terizidone
Authors: Chirehwa Maxwell T. , Court Richard , de Kock Mariana , Wiesner Lubbe , de Vries Nihal , Harding Joseph , Gumbo Tawanda , Maartens Gary , Warren Rob , Denti Paolo , McIlleron Helen
Published: August 2020

Cycloserine is a WHO group B drug for the treatment of multidrug-resistant tuberculosis (TB). Pharmacokinetic/pharmacodynamic data for cycloserine when dosed as terizidone are sparse. The aim of this analysis was to describe the population pharmacokinetics of cycloserine when administered as terizidone and predict the doses of terizidone attaining cycloserine exposures associated with efficacy. The plasma cycloserine level was measured 2 to 6 weeks after treatment initiation in patients hospitalized for second-line tuberculosis treatment.
Highlights from the 2019 International Myopia Summit on ‘controversies in myopia’
Authors: Wong Chee Wai , Foo Li Lian , Morjaria Priya , Morgan Ian , Mueller Andreas , Davis Amanda , Keys Drew , He Mingguang , Sankaridurg Padmaja , Zhu Jian Feng , Hendicott Peter , Tan Donald , Saw Seang-Mei , Cheng Ching Yu , Lamoureux Ecosse Luc , Crowston Jonathan G , Gemmy Cheung Chui Ming , Sng Chelvin , Chan Cordelia , Wong Doric , Lee Shu Yen , Agrawal Rupesh , Hoang Quan V , Su Xinyi , Koh Adrian , Ngo Cheryl , Chen Hao , Wu Pei Chang , Chia Audrey , Jonas Jost B , Wong Tien Yin , Ang Marcus
Published: August 2020

Myopia is an emerging public health issue with potentially significant economic and social impact, especially in East Asia. However, many uncertainties about myopia and its clinical management remain. The International Myopia Summit workgroup was convened by the Singapore Eye Research Institute, the WHO Regional Office for the Western Pacific and the International Agency for the Prevention of Blindness in 2019. The aim of this workgroup was to summarise available evidence, identify gaps or unmet needs and provide consensus on future directions for clinical research in myopia. In this review, among the many ‘controversies in myopia’ discussed, we highlight three main areas of consensus. First, development of interventions for the prevention of axial elongation and pathologic myopia is needed, which may require a multifaceted approach targeting the Bruch’s membrane, choroid and/or sclera. Second, clinical myopia management requires co-operation between optometrists and ophthalmologists to provide patients with holistic care and a tailored approach that balances risks and benefits of treatment by using optical and pharmacological interventions. Third, current diagnostic technologies to detect myopic complications may be improved through collaboration between clinicians, researchers and industry. There is an unmet need to develop new imaging modalities for both structural and functional analyses and to establish normative databases for myopic eyes. In conclusion, the workgroup’s call to action advocated for a paradigm shift towards a collaborative approach in the holistic clinical management of myopia.
Does Fibre-fix provided to people with irritable bowel syndrome who are consuming a low FODMAP diet improve their gut health, gut microbiome, sleep and mental health? A double-blinded, randomised controlled trial
Authors: Yan Ran , Murphy Mandy , Genoni Angela , Marlow Evania , Dunican Ian C , Lo Johnny , Andrew Lesley , Devine Amanda , Christophersen Claus T
Published: August 2020

Introduction

A diet low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) is an effective way to reduce gut symptoms in people with irritable bowel syndrome (IBS). This diet reduces the intake of fermentable fibres, leading to changes of the gut microbiota and insufficient fermentation in the large bowel, resulting in reduced production of short-chain fatty acids (SCFAs), such as butyrate, which has unfavourable implications for gut health, sleep and mental health. This study will examine the effect of Fibre-fix, a supplement containing a mix of dietary fibres, on the human gut microbiome composition, fermentative capacity, sleep, quality of life (QOL) and mental health of people with IBS who consume a low FODMAP diet (LFD).

Methods and analysis

A randomised, double-blind, placebo-controlled, study design is proposed to examine whether Fibre-fix added to an existing LFD may help modulate gastrointestinal function, improve markers of sleep, mental health and promote QOL in patients with IBS. Participants will provide stool and blood samples, daily bowel symptoms diaries and 3-day diet records. Additionally, they will complete validated questionnaires relating to FODMAP intake, sleep, mental health and QOL before and after a 3-week intervention. Gut health will be assessed via faecal microbiome composition, faecal pH and SCFA levels. Alteration of sleep will be recorded using an actigraphy device worn by all participants over the whole study. Multivariate analysis will be used to examine the gut microbiome and repeated measures Analysis of variance (ANOVA) will be used for dependent variables from questionnaires related to bowel symptoms, stool type, sleep, mental health and QOL to assess the differences between intervention and control groups after adjustment for confounding variables.

Ethics and dissemination

Ethics approval was obtained from the Human Research Ethics Committee of Edith Cowan University (2019-00619-YAN). Results will be disseminated in peer-review journal publications, and conference presentations. Participants will be provided with a summary of findings once the study is completed. If Fibre-fix is shown to result in favourable changes in gut microbial composition, SCFA production, sleep and mental well-being without exacerbating symptoms, this will provide additional dietary management options for those with IBS following an LFD.

Trial registration number

ACTRN12620000032954.
Distal feeding–bowel stimulation to treat short-term or long-term pathology: a systematic review
Authors: Dilke Stella Maye , Gould Laura , Yao Mark , Souvatzi Maria , Stearns Adam , Ignjatovic-Wilson Ana , Tozer Phil , Vaizey Carolynne J
Published: August 2020

Background

Distal feeding (DF) describes the insertion of a feeding tube into a fistula or stoma to administer a liquid feed into the distal bowel. It is currently used clinically in patients who are unable to absorb enough nutrition orally. This systematic review investigates DF as a therapeutic measure across a spectrum of patients with stomas and fistulae.

Methods

A total of 2825 abstracts and 44 full-text articles were screened via OVID. Fifteen papers were included for analysis. Randomised controlled trials, cohort and observational studies investigating DF as a therapeutic measure were included.

Results

Three feeds were used across the studies—reinfusion of effluent, infusion of prebiotic or a mixture. The studies varied the length of feeding between 24 hours and 61 days, and the mode of feeding, bolus or continuous varied.

DF was demonstrated to effectively wean patients from parenteral nutrition in two papers. Two papers demonstrated a significant reduction in stoma output. Three papers demonstrated improved postoperative complication rates with distal feeding regimens, including ileus (2.85% vs 20% in unfed population, p=0.024). One paper demonstrated a reduction in postoperative stool frequency.

Conclusions

This review was limited by study heterogeneity and the lack of trial data, and in the patient groups involved, the variability in diet and length of regimen. These studies suggest that DF can significantly reduce stoma output and improve renal and liver function; however, the mechanism is not clear. Further mechanistic work on the immunological and microbiological action of DF would be important.
Gastrointestinal manifestations of COVID-19 in children: a systematic review and meta-analysis
Authors: Akobeng Anthony K , Grafton-Clarke Ciaran , Abdelgadir Ibtihal , Twum-Barimah Erica , Gordon Morris
Published: August 2020

Objectives

To summarise the published evidence on the gastrointestinal manifestations of COVID-19 in children and to determine the prevalence of gastrointestinal symptoms.

Methods

In this systematic review and meta-analysis, we searched PubMed, Embase, CINAHL and the WHO’s database of publications on novel coronavirus. We included English language studies that had described original demographic and clinical characteristics of children diagnosed with COVID-19 and reported on the presence or absence of gastrointestinal symptoms. Meta-analysis was conducted using the random-effects model. The pooled prevalence of gastrointestinal symptoms was expressed as proportion and 95% CI.

Results

The search identified 269 citations. Thirteen studies (nine case series and four case reports) comprising data for 284 patients were included. Overall, we rated four studies as having a low risk of bias, eight studies as moderate and one study as high risk of bias. In a meta-analysis of nine studies, comprising 280 patients, the pooled prevalence of all gastrointestinal symptoms was 22.8% (95% CI 13.1% to 35.2%; I2=54%). Diarrhoea was the most commonly reported gastrointestinal symptom followed by vomiting and abdominal pain.

Conclusions

Nearly a quarter of children with COVID-19 have gastrointestinal symptoms. It is important for clinicians to be aware of the gastrointestinal manifestation of COVID-19.

PROSPERO registration number

CRD42020177569.
Histopathological observations in COVID-19: a systematic review
Authors: Deshmukh Vishwajit , Motwani Rohini , Kumar Ashutosh , Kumari Chiman , Raza Khursheed
Published: August 2020

Background

Coronavirus disease-2019 (COVID-19) has caused a great global threat to public health. The World Health Organization (WHO) has declared COVID-19 disease as a pandemic, affecting the human respiratory and other body systems, which urgently demands for better understanding of COVID-19 histopathogenesis.

Objective

Data on pathological changes in different organs are still scarce, thus we aim to review and summarise the latest histopathological changes in different organs observed after autopsy of COVID-19 cases.

Materials and methods

Over the period of 3 months, authors performed vast review of the articles. The search engines included were PubMed, Medline (EBSCO & Ovid), Google Scholar, Science Direct, Scopus and Bio-Medical. Search terms used were ‘Histopathology in COVID-19’, ‘COVID-19’, ‘Pathological changes in different organs in COVID-19’ or ‘SARS-CoV-2’. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2009 guidelines were used for review writing.

Result

We identified various articles related to the histopathology of various organs in COVID-19 positive patients. Overall, 45 articles were identified as full articles to be included in our study. Histopathological findings observed are summarised according to the systems involved.

Conclusion

Although COVID-19 mainly affects respiratory and immune systems, but other systems like cardiovascular, urinary, gastrointestinal tract, reproductive system, nervous system and integumentary system are not spared, especially in elderly cases and those with comorbidity. This review would help clinicians and researchers to understand the tissue pathology, which can help in better planning of the management and avoiding future risks.
Efficacy and safety of adjunctive lacosamide in the treatment of primary generalised tonic-clonic seizures: a double-blind, randomised, placebo-controlled trial
Authors: Vossler David G , Knake Susanne , O'Brien Terence J , Watanabe Masako , Brock Melissa , Steiniger-Brach Björn , Williams Paulette , Roebling Robert
Published: August 2020

Objective

To evaluate efficacy and safety of lacosamide (up to 12 mg/kg/day or 400 mg/day) as adjunctive treatment for uncontrolled primary generalised tonic-clonic seizures (PGTCS) in patients (≥4 years) with idiopathic generalised epilepsy (IGE).

Methods

Phase 3, double-blind, randomised, placebo-controlled trial (SP0982;NCT02408523) in patients with IGE and PGTCS taking 1–3 concomitant antiepileptic drugs. Primary outcome was time to second PGTCS during 24-week treatment.

Results

242 patients were randomised and received ≥1 dose of trial medication (lacosamide/placebo: n=121/n=121). Patients (mean age: 27.7 years; 58.7% female) had a history of generalised-onset seizures (tonic-clonic 99.6%; myoclonic 38.8%; absence 37.2%). Median treatment duration with lacosamide/placebo was 143/65 days. Risk of developing a second PGTCS during 24-week treatment was significantly lower with lacosamide than placebo (Kaplan-Meier survival estimates 55.27%/33.37%; HR 0.540, 95% CI 0.377 to 0.774; p<0.001; n=118/n=121). Median time to second PGTCS could not be estimated for lacosamide (>50% of patients did not experience a second PGTCS) and was 77.0 days for placebo. Kaplan-Meier estimated freedom from PGTCS at end of the 24-week treatment period (day 166) for lacosamide/placebo was 31.3%/17.2% (difference 14.1%; p=0.011). More patients on lacosamide than placebo had ≥50% (68.1%/46.3%) or ≥75% (57.1%/36.4%) reduction from baseline in PGTCS frequency/28 days, or observed freedom from PGTCS during treatment (27.5%/13.2%) (n=119/n=121). 96/121 (79.3%) patients on lacosamide had treatment-emergent adverse events (placebo 79/121 (65.3%)), most commonly dizziness (23.1%), somnolence (16.5%), headache (14.0%). No patients died during the trial.

Conclusions

Lacosamide was efficacious and generally safe as adjunctive treatment for uncontrolled PGTCS in patients with IGE.
Follow-up outcomes of intracranial aneurysms treated using braided or laser-cut stents with closed-cell design: a propensity score-matched case-controlled comparison
Authors: Lim JeongWook , Cho Young Dae , Hong Noah , Lee Jeongjun , Yoo Dong Hyun , Kang Hyun-Seung
Published: August 2020

Background

The impact of various stents on patients with intracranial aneurysms who undergo stent-assisted coiling has been debated. We conducted this study to compare follow-up outcomes of coiling procedures involving braided or laser-cut stents with closed-cell design. A propensity score-matched case-controlled analysis was applied.

Methods

A total of 413 intracranial aneurysms consecutively coiled using laser-cut (n=245) or braided stents (n=168) in procedures performed between September 2012 and June 2017 were eligible for study. Time-of-flight magnetic resonance angiography, catheter angiography, or both were used to gauge occlusive status after coiling. Recanalization was determined by Raymond classification (complete occlusion vs recanalization). A propensity score-matched analysis was conducted, based on probability of stent type in use.

Results

Ultimately, 93 coiled aneurysms (22.5%) showed some recanalization (minor, 51; major, 42) during the follow-up period (mean 21.7±14.5 months). Patient gender (P=0.042), hyperlipidemia (P=0.015), size of aneurysm (P=0.004), neck size (P<0.001), type of aneurysm (P<0.001), and packing density (P=0.024) differed significantly by group. Midterm and cumulative recanalization incidence rates in the braided-stent group were initially lower than those of the laser-cut stent group (P=0.009 and P=0.037, respectively) but they did not differ significantly after 1:1 propensity score matching (midterm OR=0.88, P=0.724; cumulative HR=0.91, P=0.758).

Conclusion

In stent-assisted coiling of intracranial aneurysms, laser-cut and braided stent groups produced similar outcomes in follow-up. Consequently, product selection may hinge on suitability for deployment rather than anticipated results.
Flower morphogenesis and gametophyte fertility attest to the rare condition of gynomonoecy in Parietaria debilis (Urticaceae)
Authors: Pedersoli Giseli Donizete , Teixeira Simone Pádua
Published: August 2020

Parietaria debilis G. Forst. is gynomonoecious, which is a rare condition in the Urticaceae family and among angiosperms. Apetalous flowers of two different morph types (monoclinous, pistillate) occur in the same inflorescence and are reduced in size and in the number of whorls and of organs per whorl. The objective of this study was to compare the morphogenesis of monoclinous and pistillate flowers to determine whether the monoclinous flowers produce fertile gametophytes, and elucidate the pathways leading to the absence of stamens and to the changes in number of whorls and organs per whorl. Flower buds and flowers (non-fertilized, fertilized) were processed for surface and anatomical studies. Pollen ultrastructure and viability were determined. Inflorescences with fertilized flowers were checked for the presence and location of fruits/viable seeds. The monoclinous flower has four sepals, four stamens, and a uniovulate pseudomonomerous gynoecium. In the pistillate flower, the stamens are absent or, rarely, aborted. No petals are formed. The gynoecium is pseudomonomerous, originated as a central primordium that differentiates into two carpels, but only one develops and houses an ovule. Monoclinous and pistillate flowers produce viable seeds. Thus, our data confirmed that this species is indeed gynomonoecious.
Evaluation of acetolactate synthase/acetohydroxyacid synthase – inhibiting herbicide spot applications and mesotrione tank mixtures for narrow-leaved goldenrod management in lowbush blueberry
Authors: White Scott N.
Published: August 2020

Narrow-leaved goldenrod is a common creeping herbaceous perennial weed in lowbush blueberry that is difficult to manage due to limited control from pre-emergence hexazinone applications and incomplete control from post-emergence mesotrione applications. The objectives of this research were to (1) evaluate a range of summer and fall non-bearing year acetolactate synthase/ acetohydroxyacid synthase (ALS/AHAS) – inhibiting herbicide spot applications for narrow-leaved goldenrod control, and (2) evaluate broadcast applications of mesotrione applied alone or in tank mixture with foramsulfuron, nicosulfuron + rimsulfuron, flazasulfuron, and clopyralid for crop tolerance and management of narrow-leaved goldenrod in lowbush blueberry. Summer non-bearing year spot applications of glyphosate and flazasulfuron caused >90% visual injury to narrow-leaved goldenrod and reduced both non-bearing and bearing year shoot density. Spot applications of tribenuron methyl, foramsulfuron, nicosulfuron + rimsulfuron, halosulfuron, and pyroxsulam caused variable injury and did not consistently reduce narrow-leaved goldenrod shoot density. Results were similar in the fall non-bearing year experiment and they indicate that flazasulfuron could be used as an alternative to glyphosate for spot applications to narrow-leaved goldenrod due to lower crop injury from this herbicide relative to glyphosate. Broadcast mesotrione applications injured narrow-leaved goldenrod but did not reduce shoot density. Broadcast foramsulfuron, nicosulfuron + rimsulfuron, and clopyralid applications caused <60% narrow-leaved goldenrod injury and did not reduce shoot density. Tank mixture of these herbicides with mesotrione did not improve narrow-leaved goldenrod control. Broadcast flazasulfuron applications caused >60% visual injury to narrow-leaved goldenrod and reduced non-bearing year and bearing year shoot density. Flazasulfuron efficacy was reduced when applied in tank mixture with mesotrione.
Improving zinc and copper delivery for subirrigated greenhouse-grown pot chrysanthemums
Authors: Shelp Barry J. , Flaherty Edward J. , Duncan Stephens Skye , Donetz Alyna J.
Published: August 2020

Moderate levels of zinc (3.50, 1.75 or 0.875 μmol·L−1 Zn) or copper (0.75, 0.38 or 0.19 μmol·L−1 Cu), in combination with a complete suite of other essential nutrients, were supplied up to flower bud break only, to two cultivars of subirrigated, potted, pinched chrysanthemums. Market-quality plants were produced with sufficient leaf-zinc or leaf-copper even though the delivery of the respective nutrient could be reduced by 75% compared with an industry standard. These results are interpreted as evidence for improved uptake efficiency with decreasing Zn or Cu delivery. Our modified delivery practice could contribute to low-input production of floricultural crops.
Influence of feedlot manure amendments on dissolved organic carbon in runoff during transition from continuous to legacy applications
Authors: Miller J.J. , Beasley B.W. , Owen M.L. , Hao X. , Drury C.F. , Chanasyk D.S.
Published: August 2020

Little research has compared land application of stockpiled (SM) or composted (CM) beef feedlot manure with straw (ST) or wood-chip (WD) bedding on loss of dissolved organic carbon (DOC) in runoff. We conducted a 6 yr (2013–2018) rainfall simulation-runoff study and utilized surface (0–5 cm) soil collected from a long-term (since 1998) field experiment on a clay loam soil in southern Alberta, Canada. The treatments consisted of SM or CM with ST or WD bedding applied at 13, 39, and 77 Mg·ha−1 (dry weight), as well as an unamended control and mineral fertilizer treatment. Surface soil was collected from all treatments after 15–17 (C15, C16, and C17; 2013–2015) continual annual applications and then after one to three legacy years (L1–L3, 2016–2018) after manure applications were first discontinued in 2015. The soil was packed into runoff trays, and flow-weighted mean concentrations (FWMCs) and mass loads of DOC in runoff water were determined during rainfall simulations. Mean DOC losses were generally significantly (P ≤ 0.05) lower for CM with ST bedding compared with the other manure type – bedding treatments in certain years and were consistent with this amendment having the lowest total carbon (C) content. The total C content of the amendments explained 92% of the variation in DOC concentration. Termination of long-term manure applications reduced FWMCs by 85%–91% and mass loss by 76%–89% from the C17 to L3 year. Therefore, our findings suggested that composting manure with ST or discontinued long-term manure application may reduce DOC loss in runoff.
Transgenerational plasticity mediates temperature effects on fitness in the water fleaDaphnia magna
Authors: Betini Gustavo S. , Wang Xueqi , Fryxell John M.
Published: August 2020

Phenotypic plasticity is an important way by which organisms respond to changes in their local environment, but it is not clear whether parents can buffer the negative impacts of high temperature on offspring fitness. To investigate this question, we exposed the water flea Daphnia magna Straus, 1820 and their offspring to either low (15 °C) or high (25 °C) temperature in a crossed factorial design. High parental temperature reduced the age and size at reproductive maturation and resulted in smaller mean clutch size, regardless of offspring temperature. This suggests that parents did not buffer the effects of high temperature on their offspring. However, offspring raised at high temperature that came from parents also raised at high temperature had similar adult body size and longer lifespan than offspring produced by parents exposed to low temperature. As a consequence of these apparent trade-offs, there was no detectable effect of parental temperature on offspring lifetime reproductive success. These results suggest that although transgenerational plasticity could help organisms to cope with stressful changes in their local environment, such effects might be difficult to detect in natural populations due to associated life-history trade-offs.
Simple FFH pilot experiment model based on DTT-like machine
Authors: Panza F. , Balog I. , Cemmi A. , Di Sarcina I. , Filippi F. , Mansi E. , Orsitto F. P. , Osipenko M. , Ricco G. , Ripani M. , Ciotti M.
Published: August 2020

The global need for energy in the world is constantly increasing. Critical fission reactors have proved great efficiency in the energy production, but the fear of nuclear wastes and accidents due to an uncontrolled chain reaction makes these unpleasant to public. More safe fusion reactors, on the opposite, have low efficiency. Hybrid reactors capable of using the advantages of both are studied, but not yet developed. In this paper, a simple fusion–fission pilot experiment model has been developed. A Tokamak with the same characteristics of DTT (Divertor Tokamak Test facility) has been considered as a reference machine for the fusion component. The fusion system has been coupled with a relatively simple low-power fission blanket configured into three different modes by using different fuels and materials. This model could be useful in order to investigate the properties of the fusion–fission hybrid coupling from a neutronic point of view.
The polaron at strong coupling
Authors: Seiringer Robert
Published: August 2020

We review old and new results on the Fröhlich polaron model. The discussion includes the validity of the (classical) Pekar approximation in the strong coupling limit, quantum corrections to this limit, as well as the divergence of the effective polaron mass.
Regressive models for condition diagnosing marine diesel engine by torsional vibrations on propulsion shaft-line
Authors: Luu Do Duc , Minh Nguyen Tri , Hanh Cao Duc , Hao Nguyen Huy
Published: August 2020

This paper presents results of study in building diagnostic regressive models (RMs) of cylinders in Marine Diesel Engine (MDE) using torsional vibration signal (TVS) on the propulsion shaft-line. For diagnostic purpose, the vectors of diagnostic signs (VDS) were designed and constructed based on the features of the TVS: maxima and minima relatively with [Formula: see text] working cylinders in real-time domain, or amplitudes of [Formula: see text] first harmonics ([Formula: see text] for two-stroke MDE, and [Formula: see text] for four-stroke MDE) in frequency domain. The received RMs are equations showing the relationships between the diagnostic sign [Formula: see text], [Formula: see text] ([Formula: see text] or [Formula: see text]) of the TVS and [Formula: see text] factors [Formula: see text], [Formula: see text] which specify common states of [Formula: see text] DME’s cylinders. The factor [Formula: see text] here was calculated by using firing coefficient Cfi ([Formula: see text] = 2Cfi-1; Cfi = 0 when [Formula: see text]-cylinder is misfired, and Cfi = 1 when [Formula: see text]-cylinder is normally fired) value of each cylinder. The Fractional Factorial Design of experiments (DoE) [Formula: see text] was used to build the mentioned RMs. The MDE on MV.HR.34000 DWT, with [Formula: see text] and [Formula: see text] was observed and analyzed. The calculated linear regressive models were tested based on the [Formula: see text]-distribution standard.