bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical and Theoretical Study on the Varying Speed Impact of Wedge Bodies on a Water Surface
Authors: Wen Xueliang , Liu Peiqing , Qu Qiulin , Hu Tianxiang
Published: August 2020

The varying speed impact of wedge bodies on a water surface is studied numerically and theoretically to provide a fast and accurate prediction of the pressure on the wedge surface and the motion of wedge bodies during the free impact, which can be a two-dimensional (2D) model for the strip theory or 2D + t strategy. The fluid is assumed to be incompressible, inviscid, with negligible gravity effect and surface tension effect. The computational fluid dynamics (CFD) method is based on the volume of fluid (VOF) method and global moving mesh (GMM) method. Various cases of a varying speed impact are shown for the CFD method, and a linear relationship between the pressure coefficient Cp and a dimensionless variable K is observed. To clearly explain the linear relationship between Cp and K, we follow the potential theory to derive the Cp expression based on several assumptions on the free surface drawn from the CFD results. The Cp expression and the motion of wedge bodies for a free impact derived from it are considered as an approximate solution for a varying speed impact. The approximate solution is compared with the existing analytical models and the published experimental data. The approximate solution can work well for different deadrise angles, while the existing analytical models can only be used for small deadrise angles. Good agreement is also obtained between the approximate solution and the experimental test results, including the time history of wedge acceleration and the pressure on the wedge surface.
Transition and Turbulence Modeling for the Prediction of Cavitating Tip Vortices
Authors: Liebrand Rens , Klapwijk Maarten , Lloyd Thomas , Vaz Guilherme
Published: August 2020

This study evaluates the influence of transition and turbulence modeling on the prediction of wetted and cavitating tip vortices for an elliptical wing, while investigating the numerical errors. Transition modeling increases the quality of numerical predictions since the assumption of a fully turbulent boundary layer, commonly found in literature, contributes to underprediction of the tip vortex cavity size. By applying the local correlation-based transition model (LCTM) and controlling the boundary layer thickness using different turbulent inflow conditions, the pressure in the vortex was found to reduce by 20% for an Angle of Attack (AoA) of 5 deg. The consequent increase in cavity size was found to be of a similar order of magnitude. At 9 deg AoA, transition always occurs just downstream of the leading edge, making this AoA more suitable to investigate the effect of different turbulence modeling approaches. Azimuthal and axial velocity fields are validated against stereographic-particle image velocimetry (S-PIV) measurements. The time-averaged velocity profiles predicted by delayed detached-eddy simulation (DDES) and improved delayed detached-eddy simulation (IDDES) are close to the experiments; however, no velocity fluctuations and vortex dynamics are observed around the vortex. A comparison of wetted and cavitating simulations shows that the cavity leads to a change in the balance between production and destruction of turbulence kinetic energy, which reduces the turbulent diffusion in and around the cavity compared to wetted flow conditions. Consequently, the vapor flow exhibits the characteristics of a potential flow. Whether this is physically plausible remains to be investigated.
Numerical Framework and Design Optimization of an Intrinsically Compliant 3-DOF Parallel Robot
Authors: Hussain Shahid , Jamwal Prashant K. , Kapsalyamov Akim , Ghayesh Mergen H.
Published: August 2020

Parallel robots are multiple degrees of freedom (DOFs) systems that are typically used in applications characterized by enhanced accuracy, rigidity, and large force requirements within a compact workspace. In the present research, an intrinsically compliant parallel robot with 3-DOFs, actuated using four pneumatic muscle actuators (PMA), is conceptualized, developed, and analyzed. Despite many benefits, parallel robots also offer certain challenges that arise from the highly coupled and nonlinear motion of their actuators. The small workspace of parallel robots has many singularities and solving a closed-form forward kinematics (FK) for its end-effector motion is complicated. The PMAs can provide intrinsically compliant robotic motions, however, since they are flexible, their unilateral actuation also poses constraints on the achievable DOFs. The present research focuses on analyzing kinematics and dynamics of the developed parallel robot incorporating the stiffness together with force closure analyses besides suggesting design improvements as a consequence of the singularity analysis. Design synthesis and multi-criteria optimization have been performed to obtain a robot design which may provide higher accuracies (near unity condition number), quick response to external wrench (stiffness and rigidity), and reduced actuator force requirements. SPEA2 (Improved Strength Pareto Evolutionary Algorithm) has been implemented to carry out the simultaneous optimization of design objectives and provide Pareto optimal design solutions.
Comparative Assessment of Liquid Sodium and Gallium as Emergency Coolants in Nuclear Energy Applications
Authors: Zamora Blas
Published: August 2020

The influence of the thermophysical variable properties on the buoyancy-driven flows of liquid sodium and gallium established in a cylindrical cavity is numerically investigated, for the entire range of Rayleigh number corresponding to practical applications. Axisymmetric turbulent simulations (initially steady) are obtained, considering appropriate boundary and reference conditions for simulating the emergency cooling of a nuclear reactor. The results obtained for different heating intensities are analyzed and compared. In the case of sodium, the expected decay in the heat transfer coefficients is less relevant than that previously obtained for airflows. In turn, strong differences in the gallium thermal behavior are encountered. In fact, a trend opposite to that of sodium is detected for wide ranges of Rayleigh number and heating parameter. Additional transient simulations are carried out to complete a comparative assessment of the performance of both liquid sodium and gallium as cooling agents.
Experimental Study on the Effect of Localized Blockages on the Friction Factor of a 61-Pin Wire-Wrapped Bundle
Authors: Childs Mason , Muyshondt Robert , Vaghetto Rodolfo , Nguyen Duy Thien , Hassan Yassin
Published: August 2020

The thermal-hydraulic behavior of the flow in rod bundles has motivated numerous experimental and computational investigations. Previous studies have identified potential for accumulation of debris within the small subchannels of typical wire-wrapped assemblies with subsequent total or partial blockage of subchannel coolant flow. A test campaign was conducted to study the effects of localized blockages on the bundle averaged friction factor of a tightly packed wire-wrapped rod bundle. Blockages were installed within the bundle, and fluid pressure drop was measured across one wire pitch for a Reynolds number range of 500–17,200. The Darcy–Weisbach friction factor of the perturbed rod bundle geometry was compared with that of the unblocked bundle, as well as with the predictions of a well-established friction factor correlation. Differing effects based on blockage size and location for various flow regimes were studied. A number of conclusions can be made about the effects of the blockages on the friction factor, such as an increasing effect of the blockage on friction factor with an increase in Reynolds number, a change in flow behavior in the turbulent transition flow regime near Reynolds number 3000, differences in effect on friction factor for different types of subchannel blockage, and a nonlinear trend in friction factor variation with flow area impeded for edge subchannels. To this end, all data and quantified uncertainty produced in this study are made available for comparison and validation of advanced computational tools.
Pressure and Flow Rate Fluctuations in Single- and Two-Blade Pumps
Authors: Pesch Andreas , Melzer Steffen , Schepeler Stephan , Kalkkuhl Tobias , Skoda Romuald
Published: August 2020

A comparative study on the highly unsteady flow field in single- and two-blade pumps is performed. Stationary pump characteristics, as well as pressure and flow rate fluctuations, are presented. Wall pressure fluctuations were measured in the suction and pressure pipe as well as at several locations within the volute casing by piezoresistive transducers. Flow rate fluctuations were evaluated by a recently presented measurement system based on an electromagnetic flowmeter (Melzer et al. 2020, “A System for Time-Fluctuating Flow Rate Measurements in a Single-Blade Pump Circuit,” Flow Meas. Instrum., 71, p. 101675). Measurements were accompanied by three-dimensional (3D) flow simulations with the open-source cfd software foam-extend. A thorough grid study and validation of the simulation were performed. By a complementary analysis of measurement and simulation results, distinctive differences between both pump types were observed, e.g., flow rate and pressure fluctuation magnitudes are significantly higher in the single-blade pump. In relation to the respective mean values, flow rate fluctuation magnitudes are one order lower than pressure fluctuation magnitudes for both pumps. For the two-blade pump, fluctuations attenuate toward overload irrespective of the particular pump circuit, while they rise for the single-blade pump. 3D simulation results yield detailed insight into the spatially and temporally resolved impeller–volute interaction and reveal that the single-blade impeller pushes a high-pressure flow region forward in a way as a positive displacement pump, resulting in an inherently fluctuating velocity and pressure distribution within the volute.
A Comparison of Static and Rotordynamic Characteristics for Two Types of Liquid Annular Seals With Parallelly Grooved Stator/Rotor
Authors: Li Zhigang , Fang Zhi , Li Jun
Published: August 2020

Liquid annular seals with parallelly grooved stator or rotor are used as replacements for smooth plain seals in centrifugal pumps to reduce leakage and break up contaminants within the working fluid. Parallelly grooved liquid annular seals have advantages of less leakage and smaller possibility of abrasion when the seal rotor–stator rubs in comparison to smooth plain seals. This paper deals with the static and rotordynamic characteristics of parallelly grooved liquid annular seals, which are limited in the literature. Numerical results of leakage flow rates, drag powers, and rotordynamic force coefficients were presented and compared for a grooved-stator/smooth-rotor (GS-SR) liquid annular seal and a smooth-stator/grooved-rotor (SS-GR) liquid annular seal, utilizing a modified transient computational fluid dynamics-based perturbation approach based on the multiple-frequency elliptical-orbit rotor whirling model. Both liquid annular seals have identical seal axial length, rotor diameter, sealing clearance, groove number, and geometry. The present transient computational fluid dynamics-based perturbation method was adequately validated based on the published experiment data of leakage flow rates and frequency-independent rotordynamic force coefficients for the GS-SR and SS-GR liquid annular seals at various pressure drops with differential inlet preswirl ratios. Simulations were performed at three pressure drops (4.14 bar, 6.21 bar, and 8.27 bar), three rotational speeds (2 krpm, 4 krpm, and 6 krpm) and three inlet preswirl ratios (0, 0.5, and 1.0), applying a wide rotor whirling frequency range up to 200 Hz, to analyze and compare the influences of operation conditions on the static and rotordynamic characteristics for both the GS-SR and SS-GR liquid annular seals. Results show that the present two liquid annular seals possess similar sealing capability, and the SS-GR seal produces a slightly larger (∼2–10%) drag power loss than the GS-SR seal. For small rotor whirling motion around a centered position, both seals have the identical direct force coefficients and the equal-magnitude opposite-sign cross-coupling force coefficients in the orthogonal directions x and y. For all operation conditions, both the GS-SR and SS-GR liquid annular seals possess negative direct stiffness K and positive direct damping C. The GS-SR seal produces purely positive Ceff throughout the whirling frequency range for all operation conditions, while Ceff for the SS-GR seal shows a significant decrease and transitions to negative value at the crossover frequency fco with increasing rotational speed and inlet preswirl. From a rotordynamic viewpoint, the GS-SR liquid annular seal is a better seal concept for pumps.
Damage Severity Estimation of Timber Poles Using Stress Wave Propagation and Wavelet Entropy Evolution
Authors: Bandara S. , Rajeev P. , Gad E. , Sriskantharajah B.
Published: August 2020

Timber poles are widely used in electricity transmission and telecommunication sectors throughout the world. The stress wave propagation for the condition assessment of timber poles is identified as a promising non-destructive testing (NDT) technique due to its simplicity and cost-effectiveness compared to other traditional methods. In this paper, a novel damage severity evaluation criterion for timber poles is proposed on the basis of short-time wavelet entropy of the reflected stress waves. The stress waves are generated by transverse impacts close to the ground level of the pole. The reflected stress waves are recorded and processed in the time frequency domain using the discrete wavelet transform. The decomposed signal components using discrete wavelet analysis are used to determine the wavelet entropy. The wavelet entropies of intact and damaged poles are compared to obtain the relative wavelet entropy (RWE) for damage severity estimation. Further, a numerical model for an in situ pole system is developed to simulate the transverse stress wave propagation and to evaluate the capability of the proposed defect severity estimation method. The developed numerical model is validated with experimental data from controlled testing and the data from field tests. The validated numerical model is then used to simulate different defect scenarios. The wavelet entropy is sensitive to the damage severity in timber poles and can be used as an effective tool to evaluate the severity of damages.
An investigation of the influence of the refractive shadow zone on wind turbine noise
Authors: Bolin Karl , Conrady Kristina , Karasalo Ilkka , Sjöblom Anna
Published: August 2020

This article aims to investigate if the proportion of the rotor area of a wind turbine that is in the refractive shadow zone according to a ray tracing algorithm coupled to meteorological forecast data is correlated to sound levels and amplitude modulation. The acoustic station is situated 950 m from a wind farm in Northern Sweden and the measurement period is seven months. On average, 1.9 dBA lower sound levels are measured when the part of the rotor disk of the closest turbine is in the refractive shadow zone. A higher probability of amplitude modulations are observed when around half of the turbine rotor is within the refractive shadow zone compared to conditions with no shadow zone present.
Fast, cheap tests could enable safer reopening
Authors: Service Robert F.
Published: August 2020

Models show test accuracy matters less than speed and frequency for curbing outbreaks.
A short de novo synthesis of nucleoside analogs
Authors: Meanwell Michael , Silverman Steven M. , Lehmann Johannes , Adluri Bharanishashank , Wang Yang , Cohen Ryan , Campeau Louis-Charles , Britton Robert
Published: August 2020

Short path to a complex ring

Nucleotide analogs are valuable tools and therapeutics because of their ability to interfere with processes such as DNA synthesis, which are vital to rapidly dividing cells and replicating viruses. These molecules are challenging to synthesize chemically. Meanwell
et al.
developed a “ribose last” synthetic strategy in which a fluorinated acyclic nucleic acid is formed by an
l
- or
d
-proline–catalyzed aldol reaction (see the Perspective by Miller). This intermediate can then be cyclized to yield the nucleic acid analog in one pot with control of anomeric conformation based on cyclization conditions. Nucleotide analogs accessible by this strategy include those with modifications at C2′ and C4′, purines and pyrimidines, and locked and protected products.

Science
, this issue p.
725
; see also p.
623
Ligand-recognizing motifs in plant LysM receptors are major determinants of specificity
Authors: Bozsoki Zoltan , Gysel Kira , Hansen Simon B. , Lironi Damiano , Krönauer Christina , Feng Feng , de Jong Noor , Vinther Maria , Kamble Manoj , Thygesen Mikkel B. , Engholm Ebbe , Kofoed Christian , Fort Sébastien , Sullivan John T. , Ronson Clive W. , Jensen Knud J. , Blaise Mickaël , Oldroyd Giles , Stougaard Jens , Andersen Kasper R. , Radutoiu Simona
Published: August 2020

Switching perception of friend and foe

Lysine motif receptors in plants perceive glycans that signal the presence of pathogenic or symbiotic nitrogen-fixing microbes. Bozsoki
et al.
now define the portions of these receptors that create the discriminatory binding pocket (see the Perspective by Bisseling and Geurts). The motifs were conserved in receptors that initiate immune responses, reflecting the invariable nature of the chitin fragments that they sense. Conversely, the motifs in receptors that respond to symbiotic signals were more varied, reflecting the greater diversity of the lipochitooligosaccharides (Nod factors) that they sense. With domain swapping, the authors switched the Nod factor specificity of receptors from two legume species and also enabled a chitin receptor that was otherwise dedicated to the detection of pathogenic microbes to instead recognize Nod factors.

Science
, this issue p.
663
; see also p.
620
Distorting science, putting water at risk
Authors: Sullivan S. Mažeika Patricio , Rains Mark C. , Rodewald Amanda D. , Buzbee William W. , Rosemond Amy D.
Published: August 2020

A recent rule is inconsistent with science and will compromise the integrity of U.S. waters.
Chemical vapor deposition of layered two-dimensional MoSi
2
N
4
materials
Authors: Hong Yi-Lun , Liu Zhibo , Wang Lei , Zhou Tianya , Ma Wei , Xu Chuan , Feng Shun , Chen Long , Chen Mao-Lin , Sun Dong-Ming , Chen Xing-Qiu , Cheng Hui-Ming , Ren Wencai
Published: August 2020

Stabilizing monolayer nitrides with silicon

Transition metal carbides and nitrides are nonlayered materials that in monolayer form have potentially useful electronic and chemical properties. These monolayers are usually made by chemical etching that produces flakes with surface defects that have poor air and water stability. Hong
et al.
report that introducing silicon during chemical vapor deposition growth of molybdenum nitride passivates the surface and prevents island formation. Centimeter-scale monolayer films of the semiconductor MoSi
2
N
4
form as a MoN
2
layer sandwiched by two Si-N bilayers. These layers possess high mechanical strength and ambient stability.

Science
, this issue p.
670
How it all ends
The End of Everything (Astrophysically Speaking)
Katie Mack
Scribner, 2020. 240 pp.
Authors: Halpern Paul
Published: August 2020

A light-hearted exploration of the death of the Universe serves as an effective antidote for everyday worries
Can playing together help us live together?
Authors: Paluck Elizabeth Levy , Clark Chelsey S.
Published: August 2020

A field experiment in Iraq shows that having Muslim teammates reduced Christian soccer players' prejudice
Science meets politics
A Dominant Character: The Radical Science and Restless Politics of J. B. S. Haldane
Samanth Subramanian
Norton, 2020. 400 pp.
Authors: Hughes P. William
Published: August 2020

A passion for promoting the public good guided geneticist J. B. S. Haldane's scholarship
A mathematical model reveals the influence of population heterogeneity on herd immunity to SARS-CoV-2
Authors: Britton Tom , Ball Frank , Trapman Pieter
Published: August 2020

Heterogeneity and herd immunity

In response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), some politicians have been keen to exploit the idea of achieving herd immunity. Countering this possibility are estimates derived from work on historical vaccination studies, which suggest that herd immunity may only be achieved at an unacceptable cost of lives. Because human populations are far from homogeneous, Britton
et al.
show that by introducing age and activity heterogeneities into population models for SARS-CoV-2, herd immunity can be achieved at a population-wide infection rate of ∼40%, considerably lower than previous estimates. This shift is because transmission and immunity are concentrated among the most active members of a population, who are often younger and less vulnerable. If nonpharmaceutical interventions are very strict, no herd immunity is achieved, and infections will then resurge if they are eased too quickly.

Science
, this issue p.
846
In situ structural analysis of SARS-CoV-2 spike reveals flexibility mediated by three hinges
Authors: Turoňová Beata , Sikora Mateusz , Schürmann Christoph , Hagen Wim J. H. , Welsch Sonja , Blanc Florian E. C. , von Bülow Sören , Gecht Michael , Bagola Katrin , Hörner Cindy , van Zandbergen Ger , Landry Jonathan , de Azevedo Nayara Trevisan Doimo , Mosalaganti Shyamal , Schwarz Andre , Covino Roberto , Mühlebach Michael D. , Hummer Gerhard , Krijnse Locker Jacomine , Beck Martin
Published: August 2020

Flexible spikes

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein enables viral entry into host cells by binding to the angiotensin-converting enzyme 2 (ACE2) receptor and is a major target for neutralizing antibodies. About 20 to 40 spikes decorate the surface of virions. Turoňová
et al.
now show that the spike is flexibly connected to the viral surface by three hinges that are well protected by glycosylation sites. The flexibility imparted by these hinges may explain how multiple spikes act in concert to engage onto the flat surface of a host cell.

Science
, this issue p.
203
An early start to Huntington's disease
Authors: DiFiglia Marian
Published: August 2020

The huntingtin gene mutation interferes with neurogenesis in human fetal cortex
Use of Newly Designed Primers for Quantification of Complete Ammonia-Oxidizing (Comammox) Bacterial Clades and Strict Nitrite Oxidizers in the Genus
Nitrospira
Authors: Jiang Ran , Wang Jian-Gong , Zhu Ting , Zou Bin , Wang Dan-Qi , Rhee Sung-Keun , An Dong , Ji Zhi-Yuan , Quan Zhe-Xue
Published: August 2020

Nitrospira
is a dominant nitrite-oxidizing bacterium in many artificial and natural environments. The discovery of complete ammonia oxidizers in the genus
Nitrospira
prevents the use of previously identified primers targeting the
Nitrospira
16S rRNA gene or nitrite oxidoreductase (
nxr
) gene for differential determination of strict nitrite-oxidizing bacteria (sNOB) in the genus
Nitrospira
and among comammox bacteria in this genus. We designed three novel primer sets that enabled quantification of comammox
Nitrospira
clades A and B and sNOB with high coverage, specificity, and accuracy in various environments. With the designed primer sets, sNOB and comammox
Nitrospira
were differentially estimated in drinking water systems, and we found that comammox clade A predominated over sNOB and other ammonia oxidizers in process water samples. Accurate quantification of comammox
Nitrospira
and sNOB by use of the newly designed primers will provide essential information for evaluating the contribution of
Nitrospira
to nitrification in various ecosystems.
Population Structure of Mycobacterium bovis in Germany: a Long-Term Study Using Whole-Genome Sequencing Combined with Conventional Molecular Typing Methods
Authors: Kohl Thomas A. , Kranzer Katharina , Andres Sönke , Wirth Thierry , Niemann Stefan , Moser Irmgard
Published: August 2020

Mycobacterium bovis
is the primary cause of bovine tuberculosis (bTB) and infects a wide range of domestic animal and wildlife species and humans. In Germany, bTB still emerges sporadically in cattle herds, free-ranging wildlife, diverse captive animal species, and humans. In order to understand the underlying population structure and estimate the population size fluctuation through time, we analyzed 131
M. bovis
strains from animals (
n
 = 38) and humans (
n
 = 93) in Germany from 1999 to 2017 by whole-genome sequencing (WGS), mycobacterial interspersed repetitive-unit–variable-number tandem-repeat (MIRU-VNTR) typing, and spoligotyping.
The Fungal Microbiome Is an Important Component of Vineyard Ecosystems and Correlates with Regional Distinctiveness of Wine
Authors: Liu Di , Chen Qinglin , Zhang Pangzhen , Chen Deli , Howell Kate S.
Published: August 2020

The composition of soil has long been thought to provide wine with characteristic regional flavors. Here, we show that for vineyards in southern Australia, the soil fungal communities are of primary importance for the aromas found in wines. We propose a mechanism by which fungi can move from the soil through the vine.
Rare case of a traumatic myositis ossificans in the tibialis anterior muscle
Authors: Nieuwenhuizen Chantal J , van Veldhoven Peter L J , van Oosterom Robert F
Published: August 2020

Athletes involved in contact sports can be diagnosed with traumatic myositis ossificans. Myositis ossificans is characterised by a benign ossifying lesion in soft tissue mass, most commonly preceded by a muscle contusion in the thigh. Despite the fact that it is often a self-limiting disease, treatment modalities are anti-inflammatory drugs, physiotherapy, shockwave therapy, radiation therapy or surgical resection. We report a 22-year-old competitive football player with severe ongoing pain in the lower leg after a direct trauma. An X-ray showed calcification between the tibia and fibula. An additional ultrasound confirmed the diagnosis: myositis ossificans of the tibialis anterior muscle. After treating him with anti-inflammatory drugs and physiotherapy, he was able to return to sports. Myositis ossificans of the lower leg is an uncommon, though if present, troublesome condition, occurring after a contusion.
Thoracoacromial artery injury after tube thoracostomy for pneumothorax
Authors: Leonard-Murali Shravan , Mohamed Adhnan , Woodward Ann , Blyden Dionne
Published: August 2020

In this case, a patient presented in a delayed fashion after blunt trauma is found to have a large left-sided pneumothorax, and tube thoracostomy is performed. After placement of the apically oriented tube, he developed haemothorax. CT imaging showed an area of questionable extravasation from the left subclavian artery, directly anterior to the thoracostomy tube. His haemothorax was refractory to adequate drainage with a new thoracostomy tube. He ultimately required angiography, coil embolisation and covered stent placement, followed by thoracoscopic evacuation of the haemothorax.
Lower estimated bone strength and impaired bone microarchitecture in children with type 1 diabetes
Authors: Fuusager Gitte , Milandt Nikolaj , Shanbhogue Vikram Vinod , Hermann Anne Pernille , Schou Anders Jørgen , Christesen Henrik Thybo
Published: August 2020

Introduction

Patients with type 1 diabetes has an increased risk of fracture. We wished to evaluate estimated bone strength in children and adolescents with type 1 diabetes and assess peripheral bone geometry, volumetric bone mineral density (vBMD) and microarchitecture.

Research design and methods

In a cross-sectional study, high-resolution peripheral quantitative CT (HR-pQCT) was performed of the radius and tibia in 84 children with type 1 diabetes and 55 healthy sibling controls. Estimated bone strength was assessed using a microfinite element analysis solver. Multivariate regression analyses were performed adjusting for age, sex, height and body mass index.

Results

The median age was 13.0 years in the diabetes group vs 11.5 years in healthy sibling controls. The median (range) diabetes duration was 4.2 (0.4−15.9) years; median (range) latest year Hb1Ac was 7.8 (5.9−11.8) % (61.8 (41−106) mmol/mol). In adjusted analyses, patients with type 1 diabetes had reduced estimated bone strength in both radius, β −390.6 (−621.2 to −159.9) N, p=0.001, and tibia, β −891.9 (−1321 to −462.9) N, p<0.001. In the radius and tibia, children with type 1 diabetes had reduced cortical area, trabecular vBMD, trabecular number and trabecular bone volume fraction and increased trabecular inhomogeneity, adjusted p<0.05 for all. Latest year HbA1c was negatively correlated with bone microarchitecture (radius and tibia), trabecular vBMD and estimated bone strength (tibia).

Conclusion

Children with type 1 diabetes had reduced estimated bone strength. This reduced bone strength could partly be explained by reduced trabecular bone mineral density, adverse microarchitecture and reduced cortical area. We also found increasing latest year HbA1c to be associated with several adverse changes in bone parameters. HR-pQCT holds potential to identify early adverse bone changes and to explain the increased fracture risk in young patients with type 1 diabetes.
Telemedicine, the current COVID-19 pandemic and the future: a narrative review and perspectives moving forward in the USA
Authors: Kichloo Asim , Albosta Michael , Dettloff Kirk , Wani Farah , El-Amir Zain , Singh Jagmeet , Aljadah Michael , Chakinala Raja Chandra , Kanugula Ashok Kumar , Solanki Shantanu , Chugh Savneek
Published: August 2020

A narrative review was conducted to examine the current state of the utilisation of telemedicine amid the current COVID-19 pandemic and to evaluate the benefits of continuing telemedicine usage in the future. A literature review was performed for articles related to telemedicine. Databases including PubMed, Google Scholar, Cochrane Library and Ovid MEDLINE were searched. Three reviewers independently performed article selection based on relevance to our topic. We included all articles between 1990 and 2020 related to telemedicine using the following keywords: ‘telemedicine’, ‘telehealth’, ‘policy’, ‘COVID-19’, ‘regulation’, ‘rural’, ‘physical examination’, ‘future’. A total of 60 articles were identified, and through careful selection we narrowed the final number of articles to 42 based on relevance to our topic. Telemedicine has been rapidly evolving over the past several decades. Issues with regulation and reimbursement have prevented its full immersion into the healthcare system. During the current pandemic, Centers for Medicare and Medicaid services have expanded access to telemedicine services. The advantages of telemedicine moving forward include its cost-effectiveness, ability to extend access to specialty services and its potential to help mitigate the looming physician shortage. Disadvantages include lack of available technological resources in certain parts of the country, issues with security of patient data, and challenges in performing the traditional patient examination. It is critically important that changes are made to fully immerse telemedicine services into the healthcare landscape in order to be prepared for future pandemics as well as to reap the benefits of this service in the future.
Remodeling tumor immune microenvironment (TIME) for glioma therapy using multi-targeting liposomal codelivery
Authors: Zheng Zening , Zhang Jiaxin , Jiang Jizong , He Yang , Zhang Wenyuan , Mo Xiaopeng , Kang Xuejia , Xu Qin , Wang Bing , Huang Yongzhuo
Published: August 2020

Background

Glioblastoma (GBM) treatment is undermined by the suppressive tumor immune microenvironment (TIME). Seek for effective methods for brain TIME modulation is a pressing need. However, there are two major challenges against achieving the goal: first, to screen the effective drugs with TIME-remodeling functions and, second, to develop a brain targeting system for delivering the drugs.

Methods

In this study, an α7 nicotinic acetylcholine receptors (nAChRs)-binding peptideDCDX was used to modify the codelivery liposomes to achieve a ‘three-birds-one-stone’ delivery strategy, that is, multi-targeting the glioma vessel endothelium, glioma cells, and tumor-associated macrophages that all overexpressed α7 nAChRs. A brain-targeted liposomal honokiol and disulfiram/copper codelivery system (CDX-LIPO) was developed for combination therapy via regulating mTOR (mammalian target of rapamycin) pathway for remodeling tumor metabolism and TIME. Honokiol can yield a synergistic effect with disulfiram/copper for anti-GBM.

Results

It was demonstrated that CDX-LIPO remarkably triggered tumor cell autophagy and induced immunogenic cell death, and meanwhile, activated the tumor-infiltrating macrophage and dendritic cells, and primed T and NK (natural killer) cells, resulting in antitumor immunity and tumor regression. Moreover, CDX-LIPO promoted M1-macrophage polarization and facilitated mTOR-mediated reprogramming of glucose metabolism in glioma.

Conclusion

This study developed a potential combinatory therapeutic strategy by regulation of TIME and a ‘three-birds-one-stone’-like glioma-targeting drug delivery system.
Genetic ablation of adipocyte PD-L1 reduces tumor growth but accentuates obesity-associated inflammation
Authors: Wu Bogang , Chiang Huai-Chin , Sun Xiujie , Yuan Bin , Mitra Payal , Hu Yanfen , Curiel Tyler J , Li Rong
Published: August 2020

The programmed death-ligand 1 (PD-L1)-dependent immune checkpoint attenuates host immunity and maintains self-tolerance. Imbalance between protective immunity and immunopathology due to altered PD-L1 signaling can lead to autoimmunity or tumor immunosuppression. The role of the PD-L1-dependent checkpoint in non-immune system is less reported. We previously found that white adipocytes highly express PD-L1. Here we show that adipocyte-specific PD-L1 knockout mice exhibit enhanced host anti-tumor immunity against mammary tumors and melanoma with low or no tumor PD-L1. However, adipocyte PD-L1 ablation in tumor-free mice also exacerbates diet-induced body weight gain, pro-inflammatory macrophage infiltration into adipose tissue, and insulin resistance. Low PD-L1 mRNA levels in human adipose tissue correlate with high body mass index and presence of type 2 diabetes. Therefore, our mouse genetic approach unequivocally demonstrates a cell-autonomous function of adipocyte PD-L1 in promoting tumor growth and inhibiting antitumor immunity. In addition, our work uncovers a previously unrecognized role of adipocyte PD-L1 in mitigating obesity-related inflammation and metabolic dysfunction.
Therapeutic plasma exchange clears circulating soluble PD-L1 and PD-L1-positive extracellular vesicles
Authors: Orme Jacob J , Enninga Elizabeth Ann L , Lucien-Matteoni Fabrice , Dale Heather , Burgstaler Edwin , Harrington Susan M , Ball Matthew K , Mansfield Aaron S , Park Sean S , Block Mathew S , Markovic Svetomir N , Yan Yiyi , Dong Haidong , Dronca Roxana S , Winters Jeffrey L
Published: August 2020

Background

Trans-acting programmed death-ligand 1 (PD-L1) derives from malignant cells in three known forms. High levels of secreted splice variant PD-L1 (sPD-L1), ADAM10/ADAM17-shed sPD-L1, and PD-L1-positive extracellular vesicles (evPD-L1) each predict poor prognosis and limited response to PD-(L)1 checkpoint inhibitors in cancer. To our knowledge, no clinical intervention has reduced any of these circulating forms of extracellular PD-L1. Here, we explore therapeutic plasma exchange (TPE) as a treatment to reduce circulating extracellular PD-L1.

Results

In patients with melanoma, sPD-L1 levels above 0.277 ng/mL predicted inferior overall survival. In patients undergoing TPE for non-malignant indications, each TPE session removed a mean 70.8% sPD-L1 and 73.1% evPD-L1 detectable in plasma. TPE also reduced total and ADAM10-positive extracellular vesicles.

Conclusion

Here, we report the first known clinical intervention to remove either sPD-L1 or evPD-L1 from plasma in vivo. TPE reduces plasma sPD-L1 and evPD-L1 in vivo and may have a role in treatment with immunotherapy. TPE may also prove useful in patients with other extracellular vesicle-related conditions.
Atrial fibrillation in patients with an atrial septal defect in a single centre cohort during a long clinical follow-up: its association with closure and outcome of therapy
Authors: Evertz Reinder , Reinders Manon , Houck Charlotte , ten Cate Tim , Duijnhouwer Anthonie L. , Beukema Rypko , Westra Sjoerd , Vernooy Kevin , de Groot Natasja M S
Published: August 2020

Objective

Currently, consensus is lacking on the relation between closure of atrial septal defect (ASD) and the incidence of atrial fibrillation (AF), which is a known complication in ASD patients. More importantly, studies reporting on the treatment applied for AF in ASD patients are scarce. The aims of this study were (1) to assess the incidence of AF in ASD patients, (2) to study the relation between closure and AF and (3) to evaluate applied treatment strategies.

Methods

A single-centre retrospective study in 173 patients with an ASD was performed. We analysed the incidence of AF, the relation of AF with closure, method of closure and the treatment success of therapies applied.

Results

Almost 20% of patients with an ASD developed AF, with a mean age of 59 (±14) years at first presentation of AF during a median clinical follow-up of 43 (29–59) years. Older age (OR 1.072; p<0.001) and a dilated left atrium (OR 3.727; p=0.009) were independently associated with new-onset AF. Closure itself was not independently associated with AF. First applied treatment strategy was rhythm control in 77%. Of the 18 patients treated with antiarrhythmic drugs 50% had at least 1 recurrence of AF.

Conclusion

No clear relation between closure of the ASD and AF could be assessed. This is the first study describing applied therapy for AF in ASD patients of which medical rhythm control was the most applied strategy with a disappointing efficacy.
Implementing smokeless tobacco control policy in Pakistan: a qualitative study among Naswar supply chain actors
Authors: Ahmad Fayaz , Boeckmann Melanie , Khan Zohaib , Zeeb Hajo , Khan Muhammad Naseem , Ullah Safat , Dreger Steffen , Haq Zia Ul , Forberger Sarah
Published: August 2020

Objective

To obtain insights into the perceptions of barriers and facilitators to implementation of the WHO Framework Convention on Tobacco Control (FCTC) among smokeless tobacco (SLT) supply chain actors in the Khyber Pakhtunkhwa province of Pakistan.

Methods

We conducted a qualitative study to investigate the perceptions about SLT control policy formulation and implementation among exclusive Naswar sellers and point of sale vendors. We conducted five focus group discussions in three districts of Khyber Pakhtunkhwa using combined deductive-inductive thematic analyses.

Results

We identified three central themes that potentially impact policy formulation, its implementation and application. The first theme examines the role of children in the Naswar business: as potential customers, and as potential heirs to a Naswar-selling business. A second theme targets the ‘business of Naswar’, which includes a specific identity of Naswar sellers, its potential to generate profits and the special case of Naswar regulation as a socially accepted and culturally rooted product. The third theme addresses the unusual ingredients of Naswar and its production process, making Naswar a health risk for consumers and producers. We also report conflicting views regarding SLT control among the supply chain actors.

Conclusions

This study provides insights into the perceptions of important SLT supply-side stakeholders regarding various SLT control policy options based on the FCTC. While there is some opposition to policy approaches like taxation and switching of business, implementing a ban on selling SLT to minors may be a viable option for policymakers in the short term.
Prediction of coupled hydromechanical behavior of unsaturated soils based on seasonal variations in hydrologic conditions
Authors: Mahmoodabadi Majid , Bryson L. Sebastian
Published: August 2020

Seasonal variations in hydrologic conditions greatly influence the hydromechanical properties of unsaturated soils. There are several models available to estimate shear strength of unsaturated soil under various hydrologic conditions. However, many of these existing models provide little to no data regarding the deformations associated with wetting and drying of unsaturated soils. The incremental hydromechanical behavior for an unsaturated soil is generally described by a constitutive framework. In this study, a modified Sheng, Fredlund, and Gens (SFG) soil constitutive model was utilized with in situ hydrologic data to simulate fully coupled mechanical behavior for an unsaturated slope over different hydrologic events. This paper also presents a hydrological prediction approach to estimate hydrologic characteristics of unsaturated soils over several wetting and drying events using only the soil-water characteristics parameters of the main drying curve. The proposed approach provides a possibility of describing long-term hydrologic behavior of unsaturated soils by means of a limited amount of in situ hydrologic data. The outcome of this study provides geotechnical engineers with the capability of estimating deformational behavior of unsaturated soils under various real-time rainfall–evapotranspiration conditions and implementing more effective emergency planning.
Intricacies of the endothelin system in human obesity: role in the development of complications and potential as a therapeutic target
Authors: Schinzari Francesca , Cardillo Carmine
Published: August 2020

Activation of the vascular endothelin-1 (ET-1) system is a key abnormality in vascular dysfunction of human obesity, especially in patients developing complications, such as the metabolic syndrome, diabetes, and atherosclerosis. Vascular insulin resistance, an increased insulin-stimulated endothelial production of ET-1 combined with impaired nitric oxide availability, is the hallmark of obesity-related vasculopathy, but dysregulated adipokine release from obese adipose tissue may contribute to the predominance of ET-1-dependent vasoconstriction. ET-1, in turn, might determine unhealthy obese adipose tissue expansion, with visceral and perivascular adipose tissue changes driving the release of inflammatory cytokines and atherogenic chemokines. In addition, ET-1 might also play a role in the development of the metabolic complications of obesity. Studies have shown inhibition of lipoprotein lipase activity by ET-1, with consequent hypertriglyceridemia. Also, ET-1 in pancreatic islets seems to contribute to beta cell dysfunction, hence affecting insulin production and development of diabetes. Moreover, ET-1 may play a role in nonalcoholic steatohepatitis. Recent clinical trials using innovative design have demonstrated that antagonism of ET-type A receptors protects against some complications of obesity and diabetes, such as nephropathy. These findings encourage further investigation to evaluate whether targeting the ET-1 system could afford better protection against other consequences of the obesity epidemic.
Commutative Lie algebras and commutative cohomology in characteristic 2
Authors: Lopatkin Viktor , Zusmanovich Pasha
Published: August 2020

We discuss a version of the Chevalley–Eilenberg cohomology in characteristic [Formula: see text], where the alternating cochains are replaced by symmetric ones.
The Rise and Fall of Modern Plagues
Authors: Sharrer G. Terry
Published: August 2020

Millennia separate smallpox, the oldest pandemic, and COVID-19, the newest. Both calamities arose from an opportunistic virus amid human crowding. A vaccine for smallpox existed since the late 18th century, but it took worldwide public health strategy to eradicate it. COVID-19 proceeds against a hive of scientific collaboration, but succeeds, so far, from weak containment policies. COVID-19 was first identified in China, but it rose to become the American pandemic.
Layering, Instabilities, and Mixing in Turbulent Stratified Flows
Authors: Caulfield C.P.
Published: August 2020

Understanding how turbulence leads to the enhanced irreversible transport of heat and other scalars such as salt and pollutants in density-stratified fluids is a fundamental and central problem in geophysical and environmental fluid dynamics. This review discusses recent research activity directed at improving community understanding, modeling, and parameterization of the subtle interplay between energy conversion pathways, instabilities, turbulence, external forcing, and irreversible mixing in density-stratified fluids. The conceptual significance of various length scales is highlighted, and in particular, the importance is stressed of overturning or scouring in the formation and maintenance of layered stratifications, i.e., robust density distributions with relatively deep and well-mixed regions separated by relatively thin interfaces of substantially enhanced density gradient.
Eosinophilic Gastroenteritis with a Relapsing and Remitting Course with Presence of Autoimmune Antibodies
Authors: Fonseka Chathuranga Lakmal , Nanayakkara Sunali , Singhapura S. D. A. L. , Herath H. M. M. , Bodinayake C. K.
Published: August 2020

Background. Eosinophilic gastroenteritis (EGE) is an uncommon disease characterized by eosinophilic infiltration of the digestive tract, which occurs due to an uncertain aetiology. Although autoimmune diseases can later present as EGE, it is unusual for EGE to have positive autoimmune antibodies without the presence of an overt autoimmune disease. Case presentation. We report a 38-year-old previously healthy man who presented with abdominal discomfort and loose stools with pleural and peritoneal effusions progressing over several weeks. His investigations revealed severe eosinophilia in peripheral blood and ascitic fluid, and a laparoscopic full-thickness biopsy from the ileum demonstrated infiltration of eosinophils in all three layers of the intestine. There were no clinical features or investigations suggestive of parasitic disease, other diseases associated with eosinophilia, or autoimmune disease. Further investigations showed a highly positive ANA, positive p-ANCA, but did not meet the criteria to diagnose a specific autoimmune disease. The eosinophilia responded to an elimination diet with gradual resolution of eosinophilia and effusions, and once it reappeared after introduction of a normal diet. Conclusion. EGE presenting as peripheral blood and ascitic fluid eosinophilia with the presence of pleural and/or peritoneal effusions is uncommon. Eosinophilic gastroenteritis can be associated with autoantibody positivity without any evidence of overt autoimmune disease manifestations. Elimination diet can be used as a potential option to prevent recurrences of EGE.