bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional morphology of the sperm‐containing chambers of the sea slug Okenia polycerelloides in the context of sexual selection
Authors: Sales Licia , Marian José Eduardo A. R.
Published: August 2020

Sea slugs are interesting models to study post‐copulatory sexual selection in simultaneous hermaphrodites due to the enormous variation of their reproductive systems. However, the knowledge of the functional morphology of their reproductive system is limited to few species, and it is rarely discussed in the context of sexual selection theory. In this study, we investigated the functional morphology of the sperm‐containing chambers (i.e., ampulla, seminal receptacle, and bursa copulatrix) of the reproductive system of Okenia polycerelloides (Ortea & Bouchet, 1983), based on light, confocal, and electron microscopy. Although the morphology of the ampulla is similar to other species, indicating that it is a site for autosperm storage, we found some sperm facing the ampullar epithelium, a feature commonly regarded as characteristic of the seminal receptacle of sea slugs. The seminal receptacle of O. polycerelloides showed secretory activity and contained sperm with distribution and orientation suggestive of stratification of allosperm from distinct mating events, a feature that would affect sperm competition. The bursa copulatrix had epithelial cells with secretory and absorptive characteristics, and contained degraded sperm and yolk granules within its lumen. Comparative analyses of the contents of each organ demonstrated that sperm digestion occurs in the bursa copulatrix and affects sperm heads first, changing their morphology from slender and curved to shorter and ellipsoid before complete lysis. Although digestion and absorption of surplus sperm are currently the main hypothesized functions for the bursa copulatrix, its role in cryptic female choice should not be ruled out. The close structural connection between the seminal receptacle and bursa copulatrix, as well as their muscular walls, would enable control over the fate of the sperm received in each mating event, that is, storage or digestion.
Thermoresponsive Cationic Block Copolymer Brushes for Temperature‐Modulated Stem Cell Separation
Authors: Nagase Kenichi , Ota Ayumu , Hirotani Tadashi , Yamada Sota , Akimoto Aya Mizutani , Kanazawa Hideko
Published: August 2020

Recently, cell separation methods have become important for preparing cells for transplantation therapy. In this study, a thermoresponsive cationic block copolymer brush is developed as an effective cell separation tool. This brush is prepared on glass surfaces using two steps of activator regenerated by electron transfer–atom transfer radical polymerization (ARGET‐ATRP). The cationic segment is prepared in the first step of the ARGET‐ATRP of N,N‐dimethylaminopropylacrylamide (DMAPAAm). In the second step, the thermoresponsive segment is prepared, attached to the bottom cationic segment, through ARGET‐ATRP with N‐isopropylacrylamide (NIPAAm). The cell adhesion behavior of the prepared thermoresponsive cationic copolymer, PDMAPAAm‐b‐PNIPAAm, brush is observed using umbilical cord‐derived mesenchymal stem cells (UCMSC), fibroblasts, and macrophages. At 37 °C, all three types of cells adhere to the thermoresponsive cationic copolymer brush. Then, by reducing the temperature to 20 °C, the adhered UCMSC are detached from the copolymer brush, whereas the fibroblasts and macrophages remain adhered to the copolymer brush. Using this copolymer brush, UCMSC can be purified from the cell mixture simply by changing the temperature. Therefore, the prepared thermoresponsive cationic copolymer brush is useful as a cell separation tool for the purification of mesenchymal stem cells.
Using One Photoredox Catalyst to Simultaneously Mediate Two Different Polymerizations for Photo‐Triggered Multi‐Component Orthogonal Polymerizations
Authors: Zhang Weidong , Shen Shuyi , Zhang Zhengbiao , Huang Yan , Weng Yuyan , Chen Gaojian
Published: August 2020

The development of multi‐component orthogonal polymerizations (MOPs) with simple procedure and high efficiency is crucial for rational polymer synthesis. In this work, photo‐triggered Cu(I)‐catalyzed azide‐alkyne cycloaddition (CuAAC) polymerization are first investigated, employing copper(II) thioxanthone carboxylate (Cu(TX)2) as photoredox catalyst and sunlight as stimuli. Then, the novel MOPs using one photoredox catalyst, Cu(TX)2 to simultaneously mediate two different photopolymerizations, are successfully realized in one‐pot, where photo‐induced electron transfer atom transfer radical polymerization and photo‐activated CuAAC polymerization can effectively proceed in a one‐pot and non‐interfering fashion to afford predetermined copolymers with well‐defined structure.
Effect of microstructure and low cycle fatigue deformation on tensile properties of P91 steel
Authors: Mariappan K. , Shankar V. , Bhaduri A.K.
Published: August 2020

Isothermal furnace heat treatments were carried out to simulate the microstructures of inter‐critical, fine grain and coarse grain heat‐affected zones of P91 steel weld joint at different soaking temperatures ranging from just above AC1 (837 °C) to well above AC3 (903 °C). Interrupted low cycle fatigue tests were performed on the specimens of P91 steel up to 5 %, 10 %, 30 %, and 50 % of the total fatigue life at the strain amplitude of ±0.6 %, strain rate of 0.003 s−1 and temperatures of 550 °C and 600 °C. Subsequently, tensile tests were conducted on the interrupt tested specimens at the same strain rate and temperatures. Soaking at the inter‐critical temperature region reduces / deteriorates the tensile and yield strengths of base metal compared to fine grain and coarse grain regions. The inter‐critical heat‐affected zone accounted higher damage contribution towards the overall tensile behavior of the actual P91 steel weld joint. Substructural coarsening during strain cycling at elevated temperatures attributes to the rapid reduction in the initial yield strength up to 10 % of fatigue life of P91 steel. A higher amount of plastic strain accumulation during low cycle fatigue deformation resulted in a decrease in fatigue life of the inter‐critical heat‐affected zone of P91 steel.
Thermomechanical treatment of A380 aluminum alloy for globular thixo feedstock
Authors: Dumanić I. , Krolo J. , Lela B. , Jozić S.
Published: August 2020

The main aim of this paper is to present and evaluate thermomechanical treatment for semi‐solid feedstock production of A380 (AlSi9Cu3(Fe)) aluminum alloy. Equal channel angular pressing (ECAP) is used to heavily deform and refine as cast dendritic microstructure with needle like eutectic appearance. The deformed microstructure is easily changed to globular microstructure by recovery and recrystallization mechanisms during heating at the semi‐solid temperature range which is a crucial factor for quality semi‐solid feedstock preparation. The microstructural evolutions investigations during semi‐solid heating at different holding times is carried out utilizing optical microscope and scanning electron microscope accompanied by energy dispersive x‐ray spectroscopy. Homogeneous distribution of the silicon particles and intermetallic compounds around globular primary aluminum phase is observed. The used approach is appropriate and seems highly promising for preparation of the quality semi‐solid feedstock.
The unconditional stability and mass‐preserving S‐DDM scheme for solving parabolic equations in three dimensions
Authors: Zhou Zhongguo , Gu Jingwen , Li Lin , Pan Hao , Wang Yan
Published: August 2020

In this paper, the unconditional stability and mass‐preserving splitting domain decomposition method (S‐DDM) for solving three‐dimensional parabolic equations is analyzed. At each time step level, three steps (x‐direction, y‐direction, and z‐direction) are proposed to compute the solutions on each sub‐domains. The interface fluxes are first predicted by the semi‐implicit flux schemes. Second, the interior solutions and fluxes are computed by the splitting implicit solution and flux coupled schemes. Last, we recompute the interface fluxes by the explicit schemes. Due to the introduced z‐directional splitting and domain decomposition, the analysis of stability and convergence is scarcely evident and quite difficult. By some mathematical technique and auxiliary lemmas, we prove strictly our scheme meet unconditional stability and give the error estimates in L2‐norm. Numerical experiments are presented to illustrate the theoretical analysis.
Is Dietary Nonadherence Unique to Obesity and Weight Loss? Results From a Randomized Clinical Trial
Authors: Stinson Emma J. , Piaggi Paolo , Votruba Susanne B. , Venti Colleen , Lovato‐Morales Barbara , Engel Scott , Krakoff Jonathan , Gluck Marci E.
Published: August 2020

Objective

Weight stigma is associated with poor dietary adherence, yet adherence is essential for weight loss and maintenance. This study aimed to determine differences in dietary adherence and perceived hunger between lean individuals and two groups of individuals with obesity.

Methods

In a 6‐week outpatient dietary intervention (23 males; aged 48  [SD 14] years), lean participants (n = 23; BMI 23  [SD 2] kg/m2) received a weight‐maintaining energy needs (WMEN) diet, and participants with obesity (BMI 36  [SD 7]) were randomized to either WMEN (n = 18) or a 35% calorie‐reduced (CR) diet (n = 19). All food was provided, and multiple adherence and hunger ratings were assessed daily and weekly on an outpatient basis and in person at twice‐weekly visits (e.g., 24‐hour recall, diaries).

Results

Weight decreased more in the group of CR individuals with obesity (β = −0.301 kg/wk, P = 0.02) compared with the group of lean individuals and the group of WMEN individuals with obesity. However, total percent adherence did not differ between groups (P = 0.60), and hunger scores did not change across groups over time (P = 0.08).

Conclusions

Results indicate that there are no differences in dietary adherence between lean individuals and individuals with obesity and adherence is not associated with adiposity or hunger. Thus, the belief that nonadherence (e.g., lack of willpower) is unique to obesity is untrue and may perpetuate weight bias and stigma.
Web‐based virtual reality to enhance behavioural skills training and weight loss in a commercial online weight management programme: The Experience Success randomized trial
Authors: Thomas John Graham , Goldstein Carly M. , Bond Dale S. , Hadley Wendy , Tuerk Peter W.
Published: August 2020

Objective

Commercial online weight management programmes are popular and easily accessible but often lack training in empirically validated behaviour change strategies and produce suboptimal outcomes. This study evaluated the effects of a Web‐based virtual reality (VR) programme for enhancing behavioural skills training and weight loss when offered as an adjunct to a commercial online weight management programme.

Methods

N = 146 adults with overweight/obesity (body mass index [BMI] 27‐40 kg/m2) were randomized to 6 months of no‐cost access to the Weight Watchers (WW) online platform alone or enhanced with the Experience Success (WW + ES) programme, consisting of four Web‐based VR sessions for training in behavioural weight‐loss skills related to the home environment, the workplace, physical activity and social situations (i.e., a party at a friend's house). Weight was measured at the research centre at baseline, 3 and 6 months.

Results

Both groups achieved statistically significant weight loss across the trial, with no difference in mean ± standard error (SE) weight loss between WW and WW + ES at 3 months (2.7 ± 1.1 kg vs. 4.2 ± 1.1 kg, respectively; P = .086) but greater weight loss in WW + ES at 6 months (2.6 ± 1.3 kg vs. 4.9 ± 1.3 kg, respectively; P = .042).

Conclusions

This study demonstrates the potential of Web‐based VR skills training to enhance outcomes of commercial online weight management programmes that are widely accessible. Compared with traditional didactic methods for online skills training, VR simulation provides opportunities to learn behavioural skills via modelling and experiment with skills in real‐world situations. More research is needed to identify specific behavioural mechanisms by which ES may improve outcomes.
Oxygen concentration and modeling thermal decomposition of a high‐performance material: A case study of polyimide (Cirlex)
Authors: Ramgobin Aditya , Fontaine Gaëlle , Bourbigot Serge
Published: August 2020

Kinetic decomposition models for the thermal decomposition of a high‐performance polymeric material (Polyimide, PI) were determined from specific techniques. Experimental data from thermogravimetric analysis (TGA) and previously elucidated decomposition mechanism were combined with numerical simulating tool to establish a comprehensive kinetic model for the decomposition of PI under three atmospheres: nitrogen, 2% oxygen, and synthetic air. Multistaged kinetic models with subsequent and competitive reactions were established by taking into consideration the different types of reactions that may be occurring during the thermal decomposition of the material (chain scission, thermo‐oxidation, char formation). The decomposition products and decomposition mechanism of PI which was established in our previous report allowed for the elucidation of the kinetic decomposition models. A three‐staged kinetic thermal decomposition pathway was a good fit to model the thermal decomposition of PI under nitrogen. The kinetic model involved an autocatalytic type of reaction followed by successive nth order reactions. Such types of models were set up for the evaluation of the kinetics of the thermal decomposition of PI under 2% oxygen and in air, leading to models with satisfactory fidelity.
Plant cell culture extract of Cirsium eriophorum with skin pore refiner activity by modulating sebum production and inflammatory response
Authors: Laneri Sonia , Dini Irene , Tito Annalisa , Di Lorenzo Ritamaria , Bimonte Marida , Tortora Assunta , Zappelli Claudia , Angelillo Maura , Bernardi Antonietta , Sacchi Antonia , Colucci Maria Gabriella , Apone Fabio
Published: August 2020

Facial pore enlargement is considered a significant esthetic and health concern in skincare cosmetics. The pores fulfill the critical function of keeping the skin surface hydrated and protected against microbial infections. The hyperseborrhea, the stress factors, and the hormonal triggers can cause pore size enlargement, causing higher susceptibility of the skin to microbe aggressions and inflammatory reactions. Thus, reducing excessive sebum production and keeping functional pores are two of the most requested activities in skincare cosmetics. A Cirsium eriophorum cell culture extract was investigated for its role in sebum regulation, stratum corneum desquamation, and anti‐inflammation. The extract was able to regulate essential markers associated with sebum secretion and pore enlargements, such as the enzyme 5α‐reductase, which plays a central role in sebum production, and the trypsin‐like serine protease Kallikrein 5, which promotes skin exfoliation and antimicrobial response. Moreover, the extract showed a sebum‐normalizing and pore refining activity in individuals having seborrheic or acne‐prone skins, suggesting a role of the C. eriophorum extract in rebalancing altered skin conditions responsible for pore enlargement.
Understanding soil water effects on nitrogen release from controlled‐release fertilizers
Authors: Verburg Kirsten , Bristow Keith L. , McLachlan Gordon D. , Muster Tim H. , Poole Jacinta M. , Mardel James I. , Zhao Zhigan , Wittwer‐Schmid Kathy , Wong Mike T. F.
Published: August 2020

Controlled‐release fertilizers (CRFs) have the potential to deliver crop production and environmental benefits through better control of applied nitrogen (N) in cropping systems. Whereas N release from CRFs can be impacted by several factors, there has been a widely held view that soil water has little effect on N release from polymer‐coated CRFs. Past research has often studied the soil water effect as a function of soil water content. This limits the transferability of results. In this study we measured N release from a polymer‐coated urea (PCU) and a polymer‐sulfur–coated urea (PSCU) using undisturbed soil cores at set matric potentials. Soil matric potential had a significant effect on N release from PCU. Release at −1,000 kPa was delayed by up to 30 d compared with −10 kPa. Optical stereo microscopy clarified that this was linked to differences in the rate of water absorption. Theoretical considerations demonstrate that these relatively large differences could not be explained by the effect of soil matric potential on vapor flow. It is possible that soil matric potential interacted with the properties of the coating to change its permeability or the involvement of liquid flow. The effect of soil water on N release from PSCU was less clear. The magnitude of the soil water effect is, therefore, product‐specific and dependent on coating properties. The soil matric potential provided a consistent description of release patterns between soils with contrasting soil water retention characteristics. Soil water effects should hence be studied as a function of soil matric potential.
Anchoring Single‐Atom Ru on CdS with Enhanced CO2 Capture and Charge Accumulation for High Selectivity of Photothermocatalytic CO2 Reduction to Solar Fuels
Authors: Cai Songcai , Zhang Meng , Li Juanjuan , Chen Jing , Jia Hongpeng
Published: August 2020

Using renewable solar energy to CO2 conversion to chemical fuels has been widely perceived as an alternative solution for simultaneously tackling the energy crisis and the greenhouse effect. Herein, the selectivity of the photothermocataltytic CO2 reduction with H2O vapor by single‐atom dispersed‐Ru loaded CdS is regulated. Under full solar spectrum irradiation, CO as the main product with 97.2% selectivity is observed on bare CdS, whereas the intentional introduction of optimized amount of Ru metal enables CO2 reduction to CH4 with 97.6% selectivity. A series of experiments and characterizations reveal that the single‐atom dispersed Ru serves as adsorption and active sites of CO2 molecules as well as electron traps, resulting in great improvement in CO2 uptake capability of the catalyst and the effective suppression in the recombination of photogenerated carriers. Moreover, the thermal effect synchronously induced by light has a positive influence on photocatalysis, which can prominently enhance the catalytic activity without altering the product selectivity.
Structural performance assessment of a 60‐year‐old reinforced concrete bent cap
Authors: Zaborac Jarrod , Perez Bernardo , Hrynyk Trevor , Bayrak Oguzhan
Published: August 2020

As the world's reinforced concrete (RC) civil infrastructure continues to age and exhibit visual signs of distress (e.g., cracking), the challenge of how to process this visual information is becoming increasingly important. While research is ongoing in this field, limited work has been done involving structures that are truly representative of real‐world, aged civil infrastructure requiring assessment. Thus, this paper presents the results of an experimental program and subsequent numerical investigation into the performance of a diagonally cracked, RC bent cap that was removed from a 60‐year‐old bridge in Texas. Extensive work was done to document the cracking behavior and characterize the mechanical properties of the bent cap prior to ultimate load testing. The numerical investigation included both “conventional” methods and nonlinear finite element analysis (with and without consideration of existing damage). Ultimately, the results of the experimental and numerical investigations suggest that, while the bent cap was exhibiting large‐width shear cracks in service, the damage was not indicative of an impending shear failure.
Twenty‐year trends in patient referrals throughout the creation and development of a regional memory clinic network
Authors: Chen Yaohua , Lebouvier Thibaud , Skrobala Emilie , Volpe‐Gillot Lisette , Huvent‐Grelle Dominique , Jourdan Nathalie , Leroy Mélanie , Richard Florence , Pasquier Florence ,   and the Meotis network
Published: August 2020

Introduction

Memory clinics (MCs) are the main model for dementia diagnosis and care. Following the development of a MC network in Northern France, our objectives were to assess its impact on patient characteristics over 20 years.

Methods

The characteristics of new consultants were studied from 1997 to 2016.

Results

New consultants increased from 774 per year in 1997 to 26258 per year in 2016, as the number of MCs increased from 12 to 29. Over time, patients were progressively older and less educated, and more were living alone. A greater proportion of patients were referred by specialists. Referral delay and home‐to‐MC distance kept decreasing. The oldest patients were referred at a progressively less‐severe stage. The proportion of young patients kept increasing in the tertiary referral center.

Discussions

The development of a region‐wide MC network led to increased referral of vulnerable patients and differentiation of the tertiary referral center over time.
Analytic bootstrap and Witten diagrams for the ABJM Wilson line as defect CFT1
Authors: Bianchi L. , Bliard G. , Forini V. , Griguolo L. , Seminara D.
Published: August 2020

Abstract

We study local operator insertions on 1/2-BPS line defects in ABJM theory. Specifically, we consider a class of four-point correlators in the CFT1 with SU(1, 1|3) super- conformal symmetry defined on the 1/2-BPS Wilson line. The relevant insertions belong to the short supermultiplet containing the displacement operator and correspond to fluctuations of the dual fundamental string in AdS4× ℂP3 ending on the line at the boundary. We use superspace techniques to represent the displacement supermultiplet and we show that superconformal symmetry determines the four-point correlators of its components in terms of a single function of the one-dimensional cross-ratio. Such function is highly constrained by crossing and internal consistency, allowing us to use an analytical bootstrap approach to find the first subleading correction at strong coupling. Finally, we use AdS/CFT to compute the same four-point functions through tree-level AdS2 Witten diagrams, producing a result that is perfectly consistent with the bootstrap solution.
Electrochemical detection of ascorbic acid in artificial sweat using a flexible alginate/CuO-modified electrode
Authors: Ibarlucea Bergoi , Pérez Roig Arnau , Belyaev Dmitry , Baraban Larysa , Cuniberti Gianaurelio
Published: August 2020

A flexible sensor is presented for electrochemical detection of ascorbic acid in sweat based on single-step modified gold microelectrodes. The modification consists of electrodeposition of alginate membrane with trapped CuO nanoparticles. The electrodes are fabricated at a thin polyimide support and the soft nature of the membrane can withstand mechanical stress beyond requirements for skin monitoring. After characterization of the membrane via optical and scanning electron microscopy and cyclic voltammetry, the oxidative properties of CuO are exploited toward ascorbic acid for amperometric measurement at micromolar levels in neutral buffer and acidic artificial sweat, at ultralow applied potential (− 5 mV vs. Au pseudo-reference electrode). Alternatively, measurement of the horizontal shift of redox peaks by cyclic voltammetry is also possible. Obtaining a limit of detection of 1.97 μM, sensitivity of 0.103 V log (μM)−1 of peak shift, and linear range of 10–150 μM, the effect of possible interfering species present in sweat is minimized, with no observable cross-reaction, thus maintaining a high degree of selectivity despite the absence of enzymes in the fabrication scheme. With a lateral flow approach for sample delivery, repeated measurements show recovery in few seconds, with relative standard deviation of about 20%, which can serve to detect increased loss or absence of vitamin, and yet be improved in future by optimized device designs. This sensor is envisioned as a promising component of wearable devices for e.g. non-invasive monitoring of micronutrient loss through sweat, comprising features of light weight, low cost, and easy fabrication needed for such application.
A COVID-19 Airway Management Innovation with Pragmatic Efficacy Evaluation: The Patient Particle Containment Chamber
Authors: Maloney Lauren M. , Yang Ariel H. , Princi Rudolph A. , Eichert Alexander J. , Hébert Daniella R. , Kupec Taelyn V. , Mertz Alexander E. , Vasyltsiv Roman , Vijaya Kumar Thea M. , Walker Griffin J. , Peralta Edder J. , Hoffman Jason L. , Yin Wei , Page Christopher R.
Published: August 2020

The unique resource constraints, urgency, and virulence of the coronavirus disease 2019 pandemic has sparked immense innovation in the development of barrier devices to protect healthcare providers from infectious airborne particles generated by patients during airway management interventions. Of the existing devices, all have shortcomings which render them ineffective and impractical in out-of-hospital environments. Therefore, we propose a new design for such a device, along with a pragmatic evaluation of its efficacy. Must-have criteria for the device included: reduction of aerosol transmission by at least 90% as measured by pragmatic testing; construction from readily available, inexpensive materials; easy to clean; and compatibility with common EMS stretchers. The Patient Particle Containment Chamber (PPCC) consists of a standard shower liner draped over a modified octagonal PVC pipe frame and secured with binder clips. 3D printed sleeve portals were used to secure plastic sleeves to the shower liner wall. A weighted tube sealed the exterior base of the chamber with the contours of the patient’s body and stretcher. Upon testing, the PPCC contained 99% of spray-paint particles sprayed over a 90s period. Overall, the PPCC provides a compact, affordable option that can be used in both the in-hospital and out-of-hospital environments.
An approach to object-level stiffness regulation of hand-arm systems subject to under-actuation constraints
Authors: Ruiz Garate Virginia , Ajoudani Arash
Published: August 2020

When using a tool with a robotic hand-arm system, the stiffness at the grasped object plays a key role in the interaction with the environment, allowing the successful execution of the task. However, the rapidly increasing use of under-actuated hands in robotic systems due to their robustness and simplicity of control, pose limitations to the achievable object-level stiffness. Indeed, due to the serial coupling of the hand and the arm, the resulting object-level stiffness is determined by the most compliant of both elements. To address this problem, we propose a novel controller that takes into account the limited achievable geometry of the object stiffness ellipsoid given by a hand with under-actuation constraints, and exploits the contribution of the robotic arm in reshaping the final stiffness towards the desired profile. The under-actuation is illustrated by a coordinated stiffening of the hand fingers. The proposed method is experimentally validated by a hand-arm system performing a peg-in-hole task.
Comparison of a novel Compressed SENSE accelerated 3D modified relaxation-enhanced angiography without contrast and triggering with CE-MRA in imaging of the thoracic aorta
Authors: Pennig Lenhard , Wagner Anton , Weiss Kilian , Lennartz Simon , Huntgeburth Michael , Hickethier Tilman , Maintz David , Naehle Claas Philip , Bunck Alexander Christian , Doerner Jonas
Published: August 2020

To compare a novel Compressed SENSE accelerated ECG- and respiratory-triggered flow-independent 3D isotropic Relaxation-Enhanced Angiography without Contrast and Triggering (modified REACT) with standard non-ECG-triggered 3D contrast-enhanced magnetic resonance angiography (CE-MRA) for imaging of the thoracic aorta in patients with connective tissue diseases (CTD) or other aortic diseases using manual and semiautomatic measurement approaches. This retrospective, single-center analysis of 30 patients (June–December 2018) was conducted by two radiologists, who independently measured aortic diameters on modified REACT and CE-MRA using manual (Multiplanar-Reconstruction) and semiautomatic (Advanced Vessel Analysis) measurement tools on seven levels (inner edge): Aortic annulus and sinus, sinotubular junction, mid- and high-ascending aorta, aortic isthmus, and descending aorta. Bland–Altman analysis was conducted to evaluate differences between the mean values of aortic width and ICCs were calculated to assess interobserver agreement. For each level, image quality was evaluated on a four-point scale in consensus with Wilcoxon matched-pair test used to evaluate for differences between both MRA techniques. Additionally, evaluation time for each measurement technique was noted, which was compared applying one-way ANOVA. When comparing both imaging and measurement methods, CE-MRA (mean difference 0.24 ± 0.27 mm) and the AVA-tool (− 0.21 ± 0.15 mm) yielded higher differences compared to modified REACT (− 0.11 ± 0.11 mm) and the MPR-tool (0.07 ± 0.21 mm) for all measurement levels combined without yielding clinical significance. There was an excellent interobserver agreement between modified REACT and CE-MRA using both tools of measurement (ICC > 0.9). Modified REACT (average acquisition time 06:34 ± 01:36 min) provided better image quality from aortic annulus to mid-ascending aorta (p < 0.05), whereas at distal measurement levels, no significant differences were noted. Regarding time requirement, no statistical significance was found between both measurement techniques (p = 0.08). As a novel non-CE-MRA technique, modified REACT allows for fast imaging of the thoracic aorta with higher image quality in the proximal aorta than CE-MRA enabling a reliable measurement of vessel dimensions without the need for contrast agent. Thus, it represents a clinically suitable alternative for patients requiring repetitive imaging. Manual and semiautomatic measurement approaches provided comparable results without significant difference in time need.
Impact probability computation of near-Earth objects using Monte Carlo line sampling and subset simulation
Authors: Romano Matteo , Losacco Matteo , Colombo Camilla , Di Lizia Pierluigi
Published: August 2020

This work introduces two Monte Carlo (MC)-based sampling methods, known as line sampling and subset simulation, to improve the performance of standard MC analyses in the context of asteroid impact risk assessment. Both techniques sample the initial uncertainty region in different ways, with the result of either providing a more accurate estimate of the impact probability or reducing the number of required samples during the simulation with respect to standard MC techniques. The two methods are first described and then applied to some test cases, providing evidence of the increased accuracy or the reduced computational burden with respect to a standard MC simulation. Finally, a sensitivity analysis is carried out to show how parameter setting affects the accuracy of the results and the numerical efficiency of the two methods.
Unbounded Solutions to Systems of Differential Equations at Resonance
Authors: Boscaggin A. , Dambrosio W. , Papini D.
Published: August 2020

We deal with a weakly coupled system of ODEs of the type $$\begin{aligned} x_j'' + n_j^2 \,x_j + h_j(x_1,\ldots ,x_d) = p_j(t), \qquad j=1,\ldots ,d, \end{aligned}$$

x
j

′
′

+

n
j
2

x
j

+

h
j

(

x
1

,
…
,

x
d

)

=

p
j

(
t
)

,

j
=
1
,
…
,
d
,

with $$h_j$$

h
j

locally Lipschitz continuous and bounded, $$p_j$$

p
j

continuous and $$2\pi $$

2
π

-periodic, $$n_j \in {\mathbb {N}}$$

n
j

∈
N

(so that the system is at resonance). By means of a Lyapunov function approach for discrete dynamical systems, we prove the existence of unbounded solutions, when either global or asymptotic conditions on the coupling terms $$h_1,\ldots ,h_d$$

h
1

,
…
,

h
d

are assumed.
Views and Experiences of Sex, Sexuality and Relationships Following Spinal Cord Injury: A Systematic Review and Narrative Synthesis of the Qualitative Literature
Authors: Earle Sarah , O’Dell Lindsay , Davies Alison , Rixon Andy
Published: August 2020

Research examining the effects of spinal cord injury on sexuality has largely focused on physiological functioning and quantification of dysfunction following injury. This paper reports a systematic review of qualitative research that focused on the views and experiences of people with spinal cord injury on sex and relationships. The review addressed the following research question: What are the views and experiences of people with spinal cord injury of sex, sexuality and relationships following injury? Five databases were relevant and employed in the review: CINAHL (1989–2016 only), PsychInfo, PubMed, Scopus and Web of Science, for research published between 1 January 1980 and 30 November 2019. After removing duplicates, 257 records remained and were screened using a two-stage approach to inclusion and quality appraisal. Following screening, 27 met the criteria for inclusion and are reported in the paper. The review includes studies from fifteen countries across five continents. Two main approaches to data analysis summary and thematic synthesis were undertaken to analyze the qualitative data reported in the papers. The analysis revealed four main themes: sexual identity; significant and generalized others, sexual embodiment; and; sexual rehabilitation and education.
Silver nanoparticles induce genetic, biochemical, and phenotype variation in chrysanthemum
Authors: Tymoszuk Alicja , Kulus Dariusz
Published: August 2020

Despite the tremendous progress in breeding, novel and user-friendly techniques of plant improvement are desirable. The study aimed to analyze the usefulness of silver nanoparticles (AgNPs) in the breeding of chrysanthemum: one of the top ornamental plant species. In vitro regeneration of adventitious shoots from internodes of chrysanthemum ‘Lilac Wonder’ was induced on the modified Murashige and Skoog (MS) medium supplemented with 0.6 mg L−1 6-benzylaminopurine (BAP), 2 mg L−1 indole-3-acetic acid (IAA) and AgNPs at 0, 5, 10 and 20 ppm concentration. The efficiency of callogenesis and caulogenesis were analyzed after 10 weeks of culture. The concentration of chlorophylls, carotenoids, and phenolic compounds in shoots and calli were estimated. Plants obtained from 20 ppm AgNPs treatment were additionally analyzed on the genetic level using randomly amplified polymorphic DNA (RAPD) and inter simple sequence repeats (ISSR) markers. In vitro rooted shoots were acclimatized in the glasshouse and subjected to biochemical and phenotype stability evaluation. AgNPs at the highest concentration (20 ppm) suppressed both callogenesis and caulogenesis in vitro. The concentration of metabolites in callus was stable, regardless of AgNPs treatment, except for carotenoids which production was enhanced by 20 ppm AgNPs. In contrast, the content of chlorophyll a and b in shoots varied depending on AgNPs treatment. Polymorphic loci were detected in 12 and 9 AgNPs-treated-plants by RAPD and ISSR markers, respectively (one of which was common to both marker systems). Rooting and acclimatization were fully successful in all experimental combinations. Phenotype alternations were detected in six plants; one from 10 ppm AgNPs treatment and five from 20 ppm treatment. They included variation in pigment content (anthocyanins and carotenoids) and/or inflorescence shape. Interestingly, only two plants revealed both genetic and phenotype polymorphisms. No genetic or phenotype variation was detected in the control plants. In conclusion, AgNPs can be used in chrysanthemum breeding.
Balanced difficulty task finder: an adaptive recommendation method for learning tasks based on the concept of state of flow
Authors: Yazidi Anis , Abolpour Mofrad Asieh , Goodwin Morten , Hammer Hugo Lewi , Arntzen Erik
Published: August 2020

An adaptive task difficulty assignment method which we reckon as balanced difficulty task finder (BDTF) is proposed in this paper. The aim is to recommend tasks to a learner using a trade-off between skills of the learner and difficulty of the tasks such that the learner experiences a state offlowduring the learning. Flow is a mental state that psychologists refer to when someone is completely immersed in an activity. Flow state is a multidisciplinary field of research and has been studied not only in psychology, but also neuroscience, education, sport, and games. The idea behind this paper is to try to achieve a flow state in a similar way as Elo’s chess skill rating (Glickman in Am Chess J 3:59–102) and TrueSkill (Herbrich et al. in Advances in neural information processing systems, 2006) for matching game players, where “matched players” should possess similar capabilities and skills in order to maintain the level of motivation and involvement in the game. The BDTF draws analogy between choosing an appropriate opponent or appropriate game level and automatically choosing an appropriate difficulty level of a learning task. This method, as an intelligent tutoring system, could be used in a wide range of applications from online learning environments and e-learning, to learning and remembering techniques in traditional methods such as adjusting delayed matching to sample and spaced retrieval training that can be used for people with memory problems such as people with dementia.
Influence of Vacuum Support on the Fatigue Life of AlSi9Cu3(Fe) Aluminum Alloy Die Castings
Authors: Szalva Péter , Orbulov Imre Norbert
Published: August 2020

High-pressure die casting (HPDC) is a near-net-shape process that produces high quality castings with narrow dimensional tolerances. The HPDC castings are being increasingly used due to good flexibility and high productivity, especially for the automotive industry. Depending on the location of the cast components, there are ever more complex geometries and increasing strength requirements that can be achieved by the application of vacuum-assisted die casting (VPDC). The most specific features of the HPDC process are the rapid mold filling, high cooling rate and intensification pressure. As a consequence of these highlighted features, the process generally leads to the formation of casting defects, such as gas porosity, shrinkage, and entrapped oxide films. However, the VPDC casting process is capable to significantly reduce the amount of these casting defects. The aim of this work is to compare the HPDC and VPDC castings’ high-cycle fatigue behavior and to describe how the casting defects affect the fatigue failure. Before the fatigue tests, the samples were investigated with non-destructive (NDT) materials testing methods such as hydrostatic weighing, x-ray, and computer tomography (CT) to characterize the gas pore and shrinkage pore populations of the material. The AlSi9Cu3(Fe) aluminum alloy castings have been subjected to constant amplitude load by uniaxial fatigue tests in the high-cycle fatigue region with a stress asymmetry ratios of R = −1 and R = 0.1. The resulting fracture surfaces are analyzed through light optical microscopy (LOM) and scanning electron microscopy (SEM). VPDC increased the number of cycles to fracture and decreased the scatter at the given load levels compared to conventional HPDC casting. Moreover, VPDC significantly decreased the porosity size and volume, and the occurrence of oxide flakes is also decreased, resulting in the improvement in the number of cycle to failure.
Harmony or dissonance? The affordances of palliative care learning for emerging professional identity
Authors: Kilbertus Frances , Ajjawi Rola , Archibald Douglas
Published: August 2020

Introduction Patient demographics demand physicians who are competent in and embrace palliative care as part of their professional identity. Published literature describes ways that learners acquire knowledge, skills and attitudes for palliative care. These studies are, however, limited by their focus on the individual where learning is about acquisition. Viewing learning as a process of becoming through the interplay of individual, social relationships and cultures, offers a novel perspective from which to explore the affordances for professional identity development.

Methods Qualitative narrative methods were used to explore 45 narratives of memorable learning (NMLs) for palliative care recounted by 14 graduating family medicine residents in one family medicine residency program. Thematic and narrative analyses identified the affordances that support and constrain the dynamic emergence of professional identity.

Results Participants recounted affordances that supported and/or constrained their learning acting on personal (e.g. past experiences of death), interpersonal (e.g. professional support) and systemic (e.g. patient continuity) levels. Opportunities for developing professional identity were dynamic: factors acted in harmony, were misaligned, or colliding to support or constrain an emerging professional identity for palliative care practice.

Conclusion Findings highlight how individual factors interplay with interpersonal and structural conditions in the workplace in dynamic and emergent ways that may support or constrain the emergence of professional identity.
Experimental investigation of the dynamic behavior of railway track with sleeper voids
Authors: Sysyn Mykola , Nabochenko Olga , Kovalchuk Vitalii
Published: August 2020

The deterioration of the sleeper support on the ballasted track begins with the accumulation of sleeper voids. The increased dynamic loading in the voided zone and the ballast contact conditions cause the accelerated growth of the settlements in the voided zones, which results in the appearance of local instabilities like ballast breakdown, white spots, subgrade defects, etc. The recent detection and quantification of the sleeper voids with track-side and onboard monitoring can help to avoid or delay the development of local instabilities. The present paper is devoted to the study of the dynamic behavior of railway track with sleeper voids in the ballast breakdown zone. The result of the experimental track-side measurements of rail acceleration and deflection is presented. The analysis shows the existence of the dynamic impact during wheel entry in the voided zone. However, the measured dynamic impact is subjected to the bias of the track-side measurement method. Both the mechanism of the impact and the measurement aspects are explained by using the one-beam model on viscoelastic foundation. The void features in the dynamic behavior are analyzed for the purpose of track-side and onboard monitoring. A practical method of the void parameter quantification is proposed.
Suspected penicillin allergy: risk assessment using an algorithm as an antibiotic stewardship project
Authors: Querbach Christiane , Biedermann Tilo , Busch Dirk H. , Eisenhart-Rothe Rüdiger , Feihl Susanne , Filser Christiane , Gebhardt Friedemann , Heim Markus , Renz Helmut , Rothe Kathrin , Spinner Christoph D. , Starzner Melanie , Suren Christian , Trojan Monika , Brockow Knut
Published: August 2020

Background

Beta-lactam antibiotics (BLA) are the treatment of choice for a large number of bacterial infections. Putative BLA allergies are often reported by patients, but rarely confirmed. Many patients do not receive BLA due to suspected allergy. There is no systematic approach to risk stratification in the case of a history of suspected BLA allergy.

Methods

Using the available stratification programs and taking current guidelines into account, an algorithm for risk stratification, including recommendations on the use of antibiotics in cases of compellingly indicated BLA despite suspected BLA allergy, was formulated by the authors for their maximum care university hospital.

Results

The hospital is in great need of recommendations on how to deal with BLA allergies. Patient-reported information in the history forms the basis for classifying the reactions into four risk categories: (1) BLA allergy excluded, (2) benign delayed reaction, (3) immediate reaction, and (4) severe cutaneous and extracutaneous drug reaction. Recommendations strictly depend on this classification and range from use of full-dose BLA or use of BLA under certain conditions (e.g., two-stage dose escalation, non-cross-reactive BLA only) to prohibiting all BLA and the use of alternative non-BLA. In case of suspected immediate or delayed allergic reactions, there is an additional recommendation regarding subsequent allergy testing during a symptom-free interval.

Conclusion

Triage of patients with suspected BLA is urgently required. While allergy testing, including provocation testing, represents the most reliable solution, this is not feasible in all patients due to the high prevalence of BLA allergies. The risk stratification algorithm developed for the authors’ hospital represents a tool suitable to making a contribution to rational antibiotic therapy.
Two-Dimensional Platinum Diselenide: Synthesis, Emerging Applications, and Future Challenges
Authors: Gong Youning , Lin Zhitao , Chen Yue-Xing , Khan Qasim , Wang Cong , Zhang Bin , Nie Guohui , Xie Ni , Li Delong
Published: August 2020

In recent years, emerging two-dimensional (2D) platinum diselenide (PtSe2) has quickly attracted the attention of the research community due to its novel physical and chemical properties. For the past few years, increasing research achievements on 2D PtSe2 have been reported toward the fundamental science and various potential applications of PtSe2. In this review, the properties and structure characteristics of 2D PtSe2 are discussed at first. Then, the recent advances in synthesis of PtSe2 as well as their applications are reviewed. At last, potential perspectives in exploring the application of 2D PtSe2 are reviewed.
Comprehensive Examination of Dehydroxylation of Kaolinite, Disordered Kaolinite, and Dickite: Experimental Studies and Density Functional Theory
Authors: Izadifar Mohammadreza , Thissen Peter , Steudel Annett , Kleeberg Reinhard , Kaufhold Stephan , Kaltenbach Jonas , Schuhmann Rainer , Dehn Frank , Emmerich Katja
Published: August 2020

Kaolins and clays are important raw materials for production of supplementary cementitious materials and geopolymer precursors through thermal activation by calcination beyond dehydroxylation (DHX). Both types of clay contain different polytypes and disordered structures of kaolinite but little is known about the impact of the layer stacking of dioctahedral 1:1 layer silicates on optimum thermal activation conditions and following reactivity with alkaline solutions. The objective of the present study was to improve understanding of the impact of layer stacking in dioctahedral 1:1 layer silicates on the thermal activation by investigating the atomic structure after dehydroxylation. Heating experiments by simultaneous thermal analysis (STA) followed by characterization of the dehydroxylated materials by nuclear magnetic resonance spectroscopy (NMR) and scanning electron microscopy (SEM) together with first-principles calculations were performed. Density functional theory (DFT) was utilized for correlation of geometry-optimized structures to thermodynamic stability. The resulting volumes of unit cells were compared with data from dilatometry studies. The local structure changes were correlated with experimental results of increasing DHX temperature in the following order: disordered kaolinite, kaolinite, and dickite, whereupon dickite showed two dehydroxylation steps. Intermediate structures were found that were thermodynamically stable and partially dehydroxylated to a degree of DHX of 75% for kaolinite, 25% for disordered kaolinite, and 50% for dickite. These thermodynamically stable, partially dehydroxylated intermediates contained AlV while metakaolinite and metadickite contained only AlIV with a strongly distorted coordination shell. These results indicate strongly the necessity for characterization of the structure of dioctahedral 1:1 layer silicates in kaolins and clays as a key parameter to predict optimized calcination conditions and resulting reactivity.