bluuebunny/crossref_metadata_2025 huggingface dataset:
Phase-field fracture modelling of crack nucleation and propagation in porous rock
Authors: Spetz Alex , Denzer Ralf , Tudisco Erika , Dahlblom Ola
Published: February 2021

In this work, we suggest a modified phase-field model for simulating the evolution of mixed mode fractures and compressive driven fractures in porous artificial rocks and Neapolitan Fine Grained Tuff. The numerical model has been calibrated using experimental observations of rock samples with a single saw cut under uniaxial plane strain compression. For the purpose of validation, results from the numerical model are compared to Meuwissen samples with different angles of rock bridge inclination subjected to uni-axial compression. The simulated results are compared to experimental data, both qualitatively and quantitatively. It is shown that the proposed model is able to capture the emergence of shear cracks between the notches observed in the Neapolitan Fine Grained Tuff samples as well as the propagation pattern of cracks driven by compressive stresses observed in the artificial rock samples. Additionally, the typical types of complex crack patterns observed in experimental tests are successfully reproduced, as well as the critical loads.
Crack channelling mechanisms in brittle coating systems under moisture or temperature gradients
Authors: Bosco E. , Suiker A. S. J. , Fleck N. A.
Published: February 2021

Crack channelling is predicted in a brittle coating-substrate system that is subjected to a moisture or temperature gradient in the thickness direction. Competing failure scenarios are identified, and are distinguished by the degree to which the coating-substrate interface delaminates, and whether this delamination is finite or unlimited in nature. Failure mechanism maps are constructed, and illustrate the sensitivity of the active crack channelling mechanism and associated channelling stress to the ratio of coating toughness to interfacial toughness, to the mismatch in elastic modulus and to the mismatch in coefficient of hygral or thermal expansion. The effect of the ratio of coating to substrate thickness upon the failure mechanism and channelling stress is also explored. Closed-form expressions for the steady-state delamination stress are derived, and are used to determine the transition value of moisture state that leads to unlimited delamination. Although the results are applicable to coating-substrate systems in a wide range of applications, the study focusses on the prediction of cracking in historical paintings due to indoor climate fluctuations, with the objective of helping museums developing strategies for the preservation of art objects. For this specific application, crack channelling with delamination needs to be avoided under all circumstances, as it may induce flaking of paint material. In historical paintings, the substrate thickness is typically more than ten times larger than the thickness of the paint layer; for such a system, the failure maps constructed from the numerical simulations indicate that paint delamination is absent if the delamination toughness is larger than approximately half of the mode I toughness of the paint layer. Further, the transition between crack channelling with and without delamination appears to be relatively insensitive to the mismatch in the elastic modulus of the substrate and paint layer. The failure maps developed in this work may provide a useful tool for museum conservators to identify the allowable indoor humidity and temperature fluctuations for which crack channelling with delamination is prevented in historical paintings.
A phase field modeling approach of cyclic fatigue crack growth
Authors: Schreiber Christoph , Kuhn Charlotte , Müller Ralf , Zohdi Tarek
Published: February 2021

Phase field modeling of fracture has been in the focus of research for over a decade now. The field has gained attention properly due to its benefiting features for the numerical simulations even for complex crack problems. The framework was so far applied to quasi static and dynamic fracture for brittle as well as for ductile materials with isotropic and also with anisotropic fracture resistance. However, fracture due to cyclic mechanical fatigue, which is a very important phenomenon regarding a safe, durable and also economical design of structures, is considered only recently in terms of phase field modeling. While in first phase field models the material’s fracture toughness becomes degraded to simulate fatigue crack growth, we present an alternative method within this work, where the driving force for the fatigue mechanism increases due to cyclic loading. This new contribution is governed by the evolution of fatigue damage, which can be approximated by a linear law, namely the Miner’s rule, for damage accumulation. The proposed model is able to predict nucleation as well as growth of a fatigue crack. Furthermore, by an assessment of crack growth rates obtained from several numerical simulations by a conventional approach for the description of fatigue crack growth, it is shown that the presented model is able to predict realistic behavior.
Demolition of concrete by thermal shock spallation: a mesoscopic numerical study based on embedded discontinuity finite elements
Authors: Saksala Timo
Published: February 2021

This paper deals with 2D (plane strain) and axisymmetric numerical modelling of concrete fracture processes under mechanical and thermal loading. A mesoscopic modelling approach with an explicit representation of aggregates as Voronoi polygons is chosen while the concrete fracture model is based on rate-dependent embedded discontinuity finite elements with Rankine criterion indicating a new crack initiation. This choice enables the study of the effects of inherent crack populations on the response of concrete under mechanical and thermal loading. In the numerical examples, the performance of the present modelling approach is first demonstrated in the uniaxial compression and tension tests under plane strain conditions. Then, the problem of thermal spallation of concrete surface under dry conditions due to a high intensity, short duration heat flux is simulated under axisymmetric conditions. The underlying uncoupled thermo-mechanical problem is solved with an explicit time marching scheme based on the staggered approach. Different heat flux intensities and heating times as well as combined effect of surface roughness and pre-stress field are tested. The simulation results suggest that demolition of concrete structures by heat shock is a viable method.
Micromechanical modelling of ductile fracture in pipeline steel using a bifurcation-enriched porous plasticity model
Authors: Bergo Sondre , Morin David , Børvik Tore , Hopperstad Odd Sture
Published: February 2021

In this paper, we investigate the possibility of predicting ductile fracture of pipeline steel by using the Gurson–Tvergaard–Needleman (GTN) model where the onset of void coalescence is determined based on in situ bifurcation analyses. To this end, three variants of the GTN model, one of which includes in situ bifurcation, are calibrated for a pipeline steel grade X65 using uniaxial and notch tension tests. Then plane-strain tension tests and Kahn tear tests of the same material are used for assessment of the credibility of the three models. Explicit finite element simulations are carried out for all tests using the three variants of the GTN model, and the results are compared to the experimental data. The capability of the simulation models to capture onset of fracture and crack propagation in the pipeline steel is evaluated. It is found that the use of in situ bifurcation as a criterion for onset of void coalescence in each element makes the GTN model easier to calibrate with less free parameters, all the while obtaining similar or even better predictions as other widely used formulations of the GTN model over a wide range of different stress states.
Phase-field modelling: effect of an interface crack on precipitation kinetics in a multi-phase microstructure
Authors: Nigro C. F. , Bjerkén C. , Mellbin Y.
Published: February 2021

Premature failures in metals can arise from the local reduction of the fracture toughness when brittle phases precipitate. Precipitation can be enhanced at the grain and phase boundaries and be promoted by stress concentration causing a shift of the terminal solid solubility. This paper provides the description of a model to predict stress-induced precipitation along phase interfaces in one-phase and two-phase metals. A phase-field approach is employed to describe the microstructural evolution. The combination between the system expansion caused by phase transformation, the stress field and the energy of the phase boundary is included in the model as the driving force for precipitate growth. In this study, the stress induced by an opening interface crack is modelled through the use of linear elastic fracture mechanics and the phase boundary energy by a single parameter in the Landau potential. The results of the simulations for a hydrogenated ($$\alpha +\beta $$

α
+
β

) titanium alloy display the formation of a precipitate, which overall decelerates in time. Outside the phase boundary, the precipitate mainly grows by following the isostress contours. In the phase boundary, the hydride grows faster and is elongated. Between the phase boundary and its surrounding, the matrix/hydride interface is smoothened. The present approach allows capturing crack-induced precipitation at phase interfaces with numerical efficiency by solving one equation only. The present model can be applied to other multi-phase metals and precipitates through the use of their physical properties and can also contribute to the efficiency of multi-scale crack propagation schemes.
Beam network model for fracture of materials with hierarchical microstructure
Authors: Hosseini Seyyed Ahmad , Moretti Paolo , Konstantinidis Dimitrios , Zaiser Michael
Published: February 2021

We introduce a beam network model for hierarchically patterned materials. In these materials, load-parallel gaps intercept stress transmission in the load perpendicular direction in such a manner that damage is confined within hierarchically nested, load-carrying ‘modules’. We describe the morphological characteristics of such materials in terms of deterministically constructed, hierarchical beam network (DHBN) models and randomized variants thereof. We then use these models to analyse the process of damage accumulation (characterized by the locations and timings of beam breakages prior to global failures, and the concomitant avalanche statistics) and of global failure. We demonstrate that, irrespective of the degree of local disorder, failure of hierarchically (micro)structured materials is characterized by diffuse local damage nucleation which ultimately percolates on the network, but never by stress-driven propagation of a critical crack. Failure of non hierarchical reference networks, on the other hand, is characterized by the sequence of damage nucleation, crack formation and crack propagation. These differences are apparent at low and intermediate degrees of material disorder but disappear in very strongly disordered materials where the local failure strengths exhibit extreme scatter. We furthermore demonstrate that, independent of material disorder, the different modes of failure lead to significant differences in fracture surface morphology.
On 3-syzygy and unexpected plane curves
Authors: Malara Grzegorz , Pokora Piotr , Tutaj-Gasińska Halszka
Published: February 2021

In this note we study curves (arrangements) in the complex projective plane which can be considered as generalizations of free curves. We construct families of arrangements which are nearly free and possess interesting geometric properties. More generally, we study 3-syzygy curve arrangements and we present examples that admit unexpected curves.
Cultivating Decline: Agricultural Modernization Policy and Adaptive Resilience in the Yangzi Delta
Authors: Doll Ross
Published: February 2021

Since it was initiated in the mid-2000s, the Chinese central government’s agricultural modernization policy has had fundamental impacts on China’s agricultural system. Premised on creating a foundation for long-term sustainable development, modernization has broadly expanded large-scale, mechanized farming. Historically, however, China’s Yangzi River Delta achieved long-term sustainable development without capital-intensifying and mechanizing technological innovation. Rather, diverse and autonomous land use and grassroots governance practices facilitated knowledge-sharing, knowledge-building, and adaptation. Drawing on this history as a reference point for analysis, I examine the influence of agricultural modernization policy on adaptive resilience using a case study of a Yangzi Delta township that was an early recipient of central government funding in support of its contemporary effort to expand large-scale farming. I find that the implementation of agricultural modernization policy reform in Ruilin has undermined its resilient practices and features, rendering the township vulnerable to disturbance.
Ablation of mitral annular flutter ablation utilizing a left atrial anterior line versus a lateral mitral isthmus line: a systematic review and meta-analysis
Authors: Aldaas Omar M. , Lupercio Florentino , Lin Andrew Y. , Han Frederick T. , Hoffmayer Kurt S. , Raissi Farshad , Ho Gordon , Krummen David , Feld Gregory K. , Hsu Jonathan C.
Published: February 2021

Purpose

Mitral annular flutter (MAF) is a common arrhythmia after atrial fibrillation ablation. We sought to compare the efficacy and safety of catheter ablation utilizing either a left atrial anterior wall (LAAW) line or a lateral mitral isthmus (LMI) line.

Methods

We performed a systematic review for all studies that compared LAAW versus LMI lines. Risk ratio (RR) and mean difference (MD) 95% confidence intervals were measured for dichotomous and continuous variables, respectively.

Results

Four studies with a total of 594 patients were included, one of which was a randomized control trial. In the LMI ablation group, 40% of patients required CS ablation. There were no significant differences in bidirectional block (RR 1.26; 95% CI, 0.94–1.69) or ablation time (MD −1.5; 95% CI, −6.11–3.11), but LAAW ablation was associated with longer ablation line length (MD 11.42; 95% CI, 10.69–12.14) and longer LAA activation delay (MD 67.68; 95% CI, 33.47–101.89.14) when compared to LMI. There was no significant difference in pericardial effusions (RR 0.36; 95% CI, 0.39–20.75) between groups and more patients were maintained sinus rhythm (RR 1.19; 95% CI, 1.03–1.37,p= 0.02) who underwent LAAW compared to LMI.

Conclusion

Ablation of mitral annular flutter with a LAAW line compared to a LMI line showed no difference in rates of acute bidirectional block, ablation time, or pericardial effusion. However, LAAW ablation required a longer ablation line length, resulted in greater LAA activation delayed and was associated with more sinus rhythm maintenance, with the added advantage of avoiding ablation in the CS.
Organizational science and cybersecurity: abundant opportunities for research at the interface
Authors: Dalal Reeshad S. , Howard David J. , Bennett Rebecca J. , Posey Clay , Zaccaro Stephen J. , Brummel Bradley J.
Published: February 2021

Cybersecurity is an ever-present problem for organizations, but organizational science has barely begun to enter the arena of cybersecurity research. As a result, the “human factor” in cybersecurity research is much less studied than its technological counterpart. The current manuscript serves as an introduction and invitation to cybersecurity research by organizational scientists. We define cybersecurity, provide definitions of key cybersecurity constructs relevant to employee behavior, illuminate the unique opportunities available to organizational scientists in the cybersecurity arena (e.g., publication venues that reach new audiences, novel sources of external funding), and provide overall conceptual frameworks of the antecedents of employees’ cybersecurity behavior. In so doing, we emphasize both end-users of cybersecurity in organizations and employees focused specifically on cybersecurity work. We provide an expansive agenda for future organizational science research on cybersecurity—and we describe the benefits such research can provide not only to cybersecurity but also to basic research in organizational science itself. We end by providing a list of potential objections to the proposed research along with our responses to these objections. It is our hope that the current manuscript will catalyze research at the interface of organizational science and cybersecurity.
“A Free People, Controlled Only by God”: Circulating and Converting Criticism of Vaccination in Jerusalem
Authors: Kasstan Ben
Published: February 2021

This paper explores how criticism surrounding the ethics and safety of biomedical technologies circulates and ‘converts’ through global–local religious encounters, producing new claims of moral opposition and rights to religious freedom. The paper is concerned with the question of what rhetorical devices make vaccine safety doubt relevant to religiously Orthodox settings and what implications arise? Based on an ethnographic study of vaccine decision-making and non-vaccination advocacy in Jerusalem, the paper examines how opposition is forged amidst evolving global–local encounters and relations. The data reveal how Christian activists attempt to engender ethical and moral opposition to vaccination among American Orthodox Jews in Jerusalem by ‘converting’ public criticism around safety into a religious discourse of bodily governance. Pinpointing how critiques of biomedical technologies discursively ‘convert’ offers a conceptual template in anthropology to chart how counter-positions are formed and transformed amidst evolving tensions between biomedical and religious cosmologies.
The Role of Bike Sharing in Promoting Transport Resilience
Authors: Cheng Lu , Mi Zhifu , Coffman D’Maris , Meng Jing , Liu Dining , Chang Dongfeng
Published: February 2021

A resilient transport network, which is significant for urban sustainability and security, is characterized by its ability to recover from disruptions subject to natural and man-made disasters. Bike sharing could act as a viable alternative in the case of public transit disruptions given its flexibility and various social, environmental, and economic benefits. This study aims to estimate quantitatively the potential of bike sharing to promote transport resilience, by using autoregressive negative binomial time series model to investigate the effects of public transit closures on bike sharing demand in Washington, D.C. area during 2015–2017. We find that (1) bike sharing can act as a supplementary mode to enhance urban transport resilience in the case of complete transit closure; (2) the proximity of bike sharing docks to metro stations has a powerful effect on propensity to use a bike sharing program; and (3) extreme weather is one of major barriers to bicycling. Planners can enhance resilience of urban transport networks by fully considering the capacity and usage of bike sharing docks, as well as the coherence of metro stations and bike sharing docks, in distributing and rebalancing activities.
Integration of earth observation and census data for mapping a multi-temporal flood vulnerability index: a case study on Northeast Italy
Authors: Cian Fabio , Giupponi Carlo , Marconcini Mattia
Published: February 2021

Climate sciences foresee a future where extreme weather events could happen with increased frequency and strength, which would in turn increase risks of floods (i.e. the main source of losses in the world). The Mediterranean basin is considered a hot spot in terms of climate vulnerability and risk. The expected impacts of those events are exacerbated by land-use change and, in particular, by urban growth which increases soil sealing and, hence, water runoff. The ultimate consequence would be an increase of fatalities and injuries, but also of economic losses in urban areas, commercial and productive sites, infrastructures and agriculture. Flood damages have different magnitudes depending on the economic value of the exposed assets and on level of physical contact with the hazard. This work aims at proposing a methodology, easily customizable by experts’ elicitation, able to quantify and map the social component of vulnerability through the integration of earth observation (EO) and census data with the aim of allowing for a multi-temporal spatial assessment. Firstly, data on employment, properties and education are used for assessing the adaptive capacity of the society to increase resilience to adverse events, whereas, secondly, coping capacity, i.e. the capacities to deal with events during their manifestation, is mapped by aggregating demographic and socio-economic data, urban growth analysis and memory on past events. Thirdly, the physical dimension of exposed assets (susceptibility) is assessed by combining building properties acquired by census data and land-surface characteristics derived from EO data. Finally, the three components (i.e. adaptive and coping capacity and susceptibility) are aggregated for calculating the dynamic flood vulnerability index (FVI). The approach has been applied to Northeast Italy, a region frequently hit by floods, which has experienced a significant urban and economic development in the past decades, thus making the dynamic study of FVI particularly relevant. The analysis has been carried out from 1991 to 2016 at a 5-year steps, showing how the integration of different data sources allows to produce a dynamic assessment of vulnerability, which can be very relevant for planning in support of climate change adaptation and disaster risk reduction.
Adaptive Channel Selection for Robust Visual Object Tracking with Discriminative Correlation Filters
Authors: Xu Tianyang , Feng Zhenhua , Wu Xiao-Jun , Kittler Josef
Published: February 2021

Discriminative Correlation Filters (DCF) have been shown to achieve impressive performance in visual object tracking. However, existing DCF-based trackers rely heavily on learning regularised appearance models from invariant image feature representations. To further improve the performance of DCF in accuracy and provide a parsimonious model from the attribute perspective, we propose to gauge the relevance of multi-channel features for the purpose of channel selection. This is achieved by assessing the information conveyed by the features of each channel as a group, using an adaptive group elastic net inducing independent sparsity and temporal smoothness on the DCF solution. The robustness and stability of the learned appearance model are significantly enhanced by the proposed method as the process of channel selection performs implicit spatial regularisation. We use the augmented Lagrangian method to optimise the discriminative filters efficiently. The experimental results obtained on a number of well-known benchmarking datasets demonstrate the effectiveness and stability of the proposed method. A superior performance over the state-of-the-art trackers is achieved using less than $$10\%$$

10
%

deep feature channels.
Levels of heavy metal cadmium in rice (Oryza sativa L.) produced in Taiwan and probabilistic risk assessment for the Taiwanese population
Authors: Lien Keng-Wen , Pan Min-Hsiung , Ling Min-Pei
Published: February 2021

Cadmium (Cd) is a toxic pollutant that is widely spread through industrial production and agricultural practices. Epidemiological data has revealed that lifetime exposure to environmentally relevant levels of Cd increases the risk of developing various organ diseases, including chronic kidney, heart, and lung diseases, as well as nervous tissue disorders. This study assessed Cd levels in rice to determine the health risks associated with rice consumption in various age-gender subgroups in Taiwan. The distribution of Cd concentration, the lifetime average daily dose (LADD), and the hazard index (HI) were estimated by Monte Carlo simulation. In the general population, the 50th percentile LADD of Cd for male rice consumers between the ages of 19–65 years was 0.06 μg/kg body weight per day, and the hazard index (HI) 50th, 90th, and 95th percentiles were 0.16, 0.69, and 1.54, respectively. According to the HI heat map for the exposure of the general population to Cd from rice in Taiwan, the highest exposure to Cd was noted in the Yilan area (HI 0.64). Therefore, rice production in the Yilan area should be further monitored to evaluate the levels of Cd contamination.
Performance and environmental accounting of nutrient cycling models to estimate nitrogen emissions in agriculture and their sensitivity in life cycle assessment
Authors: Andrade Edilene Pereira , Bonmati August , Esteller Laureano Jimenez , Montemayor Erica , Vallejo Assumpcio Anton
Published: February 2021

Purpose

Several models are available in the literature to estimate agricultural emissions. From life cycle assessment (LCA) perspective, there is no standardized procedure for estimating emissions of nitrogen or other nutrients. This article aims to compare four agricultural models (PEF, SALCA, Daisy and Animo) with different complexity levels and test their suitability and sensitivity in LCA.

Methods

Required input data, obtained outputs, and main characteristics of the models are presented. Then, the performance of the models was evaluated according to their potential feasibility to be used in estimating nitrogen emissions in LCA using an adapted version of the criteria proposed by the United Nations Framework Convention on Climate Change (UNFCCC), and other relevant studies, to judge their suitability in LCA. Finally, nitrogen emissions from a case study of irrigated maize in Spain were estimated using the selected models and were tested in a full LCA to characterize the impacts.

Results and discussion

According to the set of criteria, the models scored, from best to worst: Daisy (77%), SALCA (74%), Animo (72%) and PEF (70%), being Daisy the most suitable model to LCA framework. Regarding the case study, the estimated emissions agreed to literature data for the irrigated corn crop in Spain and the Mediterranean, except N2O emissions. The impact characterization showed differences of up to 56% for the most relevant impact categories when considering nitrogen emissions. Additionally, an overview of the models used to estimate nitrogen emissions in LCA studies showed that many models have been used, but not always in a suitable or justified manner.

Conclusions

Although mechanistic models are more laborious, mainly due to the amount of input data required, this study shows that Daisy could be a suitable model to estimate emissions when fertilizer application is relevant for the environmental study. In addition, and due to LCA urgently needing a solid methodology to estimate nitrogen emissions, mechanistic models such as Daisy could be used to estimate default values for different archetype scenarios.
On the asymptotic behavior of the Douglas–Rachford and proximal-point algorithms for convex optimization
Authors: Banjac Goran , Lygeros John
Published: February 2021

Banjac et al. (J Optim Theory Appl 183(2):490–519, 2019) recently showed that the Douglas–Rachford algorithm provides certificates of infeasibility for a class of convex optimization problems. In particular, they showed that the difference between consecutive iterates generated by the algorithm converges to certificates of primal and dual strong infeasibility. Their result was shown in a finite-dimensional Euclidean setting and for a particular structure of the constraint set. In this paper, we extend the result to real Hilbert spaces and a general nonempty closed convex set. Moreover, we show that the proximal-point algorithm applied to the set of optimality conditions of the problem generates similar infeasibility certificates.
Influence of Process Conditions on the Local Solidification and Microstructure During Laser Metal Deposition of an Intermetallic TiAl Alloy (GE4822)
Authors: Rittinghaus Silja-Katharina , Zielinski Jonas
Published: February 2021

Temperature-time cycles are essential for the formation of microstructures and thus the mechanical properties of materials. In additive manufacturing, components undergo changing temperature regimes because of the track- and layer-wise build-up. Because of the high brittleness of titanium aluminides, preheating is used to prevent cracking. This also effects the thermal history. In the present study, local solidification conditions during the additive manufacturing process of Ti-48Al-2Cr-2Nb with laser metal deposition (LMD) are investigated by both simulation and experimental investigations. Dependencies of the build-up height, preheating temperatures, process parameters and effects on the resulting microstructure are considered, including the heat treatment. Solidification conditions are found to be dependent on the build height and thus actual preheating temperature, process parameters and location in the melt pool. Influences on both chemical composition and microstructure are observed. Resulting differences can almost be balanced through post heat treatment.
Cortisol circadian rhythm and jet-lag syndrome: evaluation of salivary cortisol rhythm in a group of eastward travelers
Authors: Paragliola Rosa Maria , Corsello Andrea , Troiani Eliana , Locantore Pietro , Papi Giampaolo , Donnini Giulia , Pontecorvi Alfredo , Corsello Salvatore Maria , Carrozza Cinzia
Published: February 2021

Purpose

The activity of the hypothalamus–pituitary–adrenal axis plays a crucial role as an endogenous stress-reactive system. Lifestyle and work often interfere with the endogenous circadian rhythms and can modify the physiological patterns of stress-hormones secretion, including cortisol. We evaluated the cortisol circadian rhythm in the “jet-lag syndrome” that is the most known condition associated with the desynchronization of the circadian rhythm.

Methods

To assess the modifications of cortisol secretion after a long-haul flight, we compared baseline and post-travel salivary cortisol rhythm in a group of 28 healthy eastward travelers (from the U.S.A. or Canada to Italy). The salivary samples were collected about 1 week before the departure at 11 p.m. on day 0 and at 8 a.m., 12 a.m. (midday) and 11 p.m. on day 1 (R0). The same samples were obtained after the landing, the day they flew back home (R1).

Results

Statistical analysis showed a significant difference between R0 and R1 for each sample considered (p < 0.005). In particular, the post-travel salivary cortisol levels detected at 11 p.m. both on day 0 and on day 1, were significantly higher than at baseline. Post-travel morning salivary cortisol levels were lower compared with basal rhythm and increased during the morning, reaching the acrophase at 12 a.m.

Conclusions

In eastward travelers, crossing more than five time zones, the cortisol circadian rhythm after the return to the East “remained behind,” being synchronized with the West time. This impaired cortisol secretion can contribute to the pathogenesis of the jet-lag syndrome.
The clinical aspects of pituitary tumour genetics
Authors: Dénes Judit , Korbonits Márta
Published: February 2021

Background

Pituitary tumours are usually benign and relatively common intracranial tumours, with under- and overexpression of pituitary hormones and local mass effects causing considerable morbidity and increased mortality. While most pituitary tumours are sporadic, around 5% of the cases arise in a familial setting, either isolated [familial isolated pituitary adenoma, related to AIP or X-linked acrogigantism], or in a syndromic disorder, such as multiple endocrine neoplasia type 1 or 4, Carney complex, McCune–Albright syndrome, phaeochromocytoma/paraganglioma with pituitary adenoma, DICER1 syndrome, Lynch syndrome, and USP8-related syndrome. Genetically determined pituitary tumours usually present at younger age and show aggressive behaviour, and are often resistant to different treatment modalities.

Subject

In this practical summary, we take a practical approach: which genetic syndromes should be considered in case of different presentation, such as tumour type, family history, age of onset and additional clinical features of the patient.

Conclusion

The identification of the causative mutation allows genetic and clinical screening of relatives at risk, resulting in earlier diagnosis, a better therapeutic response and ultimately to better long-term outcomes.
Evaluation of AQP4/TRPV4 Channel Co-expression, Microvessel Density, and its Association with Peritumoral Brain Edema in Intracranial Meningiomas
Authors: Faropoulos Konstantinos , Polia Afroditi , Tsakona Chrisi , Pitaraki Eleanna , Moutafidi Athanasia , Gatzounis George , Assimakopoulou Martha
Published: February 2021

Apart from VEGF-A pathway activation, the existence of peritumoral edema (PTBE) in meningiomas has been correlated with the expression levels of water transporter aquaporin 4 (AQP4). A novel cooperation of AQP4 with the transient receptor potential isoform 4 (TRPV4), a polymodal swelling-sensitive cation channel, has been proposed for regulating cell volume in glial cells. We investigated AQP4/TRPV4 channel co-expression in meningiomas along with the neovascularization of tumors and associate with PTBE. Immunohistochemical staining for AQP4 and TRPV4 expression was quantitatively analyzed in semi-serial sections of archival tissue from 174 patients. Microvessel density was expressed as microvessel count (MVC). PTBE was measured and edema index (EI) was assessed in 23 patients, based on magnetic resonance images (MRI) whereas mRNA levels of AQP4 and TRPV4 were evaluated in these patients using quantitative real-time PCR. High AQP4 was associated with lower–tumor grade (p < 0.05). AQP4 and TRPV4 were correlated in benign (WHO, grade I) (p < 0.0001) but not in high-grade (WHO, grades II and III) meningiomas (p > 0.05). AQP4/TRPV4 levels were independent of EI and MVC (p > 0.05). In contrast, EI was correlated to MVC (p = 0.02). AQP4/TRPV4 co-expression was detected in both edematous and non-edematous meningiomas. However, most of tumors with larger edema (EI ≥ 2) demonstrated increased levels of AQP4 and TRPV4. Importantly, peri-meningioma tissue of edematous meningiomas demonstrated significantly increased expression for AQP4 (p = 0.007) but not for TRPV4 (p > 0.05) compared with the main tumor. AQP4 and TRPV4 expression is rather associated with a response to vasogenic edema of meningiomas than with edema formation.
Quality of life, symptoms and dietary habits in oncology outpatients with malnutrition: A cross-sectional study
Authors: Sonneborn-Papakostopoulos Mira , Dubois Clara , Mathies Viktoria , Heß Mara , Erickson Nicole , Ernst Thomas , Huebner Jutta
Published: February 2021

Cancer-related malnutrition has a high prevalence, reduces survival and increases side effects. The aim of this study was to assess oncology outpatients and risk of malnutrition. Reported symptoms and quality of life (QoL) in patients found to be at risk of malnutrition or malnourished were compared to patients without malnutrition. Using a standardized questionnaire, the European Organization for Research and Treatment of Cancer Questionnaire for Quality of Life and the Mini Nutritional Assessment (MNA), patients in an outpatient cancer clinic undergoing chemotherapy treatment at a German University Hospital were assessed for nutrition, risk of malnutrition and quality of life. Based on the MNA, 39 (45.9%) patients were categorized as malnourished or at risk for malnutrition. Loss of appetite (n = 37.6%, p < 0.001) and altered taste sensation (n = 30,3%, p < 0.001) were the symptoms most frequently associated with reduced food intake. Patients with risk of malnutrition scored lower on the global health status (n = 48.15%, p = 0.001). Side effects of cancer treatments lead to a higher risk of malnutrition and as a consequence lower QoL. These side effects should be addressed more efficiently in cancer care.
The Influence of Moral Character Attributes on Adolescent Life Satisfaction: the Mediating Role of Responsible Behavior
Authors: Zhou Zheng , Shek Daniel T. L. , Zhu Xiaoqin , Lin Li
Published: February 2021

In this pioneering study, we examined the influence of moral character attributes and responsible behavior on adolescent life satisfaction, as well as the mediating role of adolescents’ responsible behavior in the influence of moral character attributes on life satisfaction in 2,474 adolescents in Hong Kong. We used a 25-item measure to assess moral character attributes, a 15-item measure to assess responsible behavior, and the 5-item Satisfaction with Life Scale to assess life satisfaction. Factor analyses using confirmatory factor analyses provided support for the factorial validity of the measures of adolescent moral character attributes, responsible behavior, and life satisfaction. Consistent with our hypotheses, moral character attributes positively predicted adolescents’ responsible behavior as well as life satisfaction, and adolescents’ responsible behavior positively predicted life satisfaction. Separate analyses using PROCESS and combined analysis using SEM via Mplus showed that adolescents’ responsible behavior mediated the influence of moral character attributes on adolescent life satisfaction. The present findings highlight the importance of moral character on adolescent well-being and support the positive youth development approach in the field.
Stabilization of the Hinge Region of Human E-selectin Enhances Binding Affinity to Ligands Under Force
Authors: Cao Thong M. , King Michael R.
Published: February 2021

Introduction

E-selectin is a member of the selectin family of cell adhesion molecules expressed on the plasma membrane of inflamed endothelium and facilitates initial leukocyte tethering and subsequent cell rolling during the early stages of the inflammatory response via binding to glycoproteins expressing sialyl LewisX and sialyl LewisA (sLeX/A). Existing crystal structures of the extracellular lectin/EGF-like domain of E-selectin complexed with sLeX have revealed that E-selectin can exist in two conformation states, a low affinity (bent) conformation, and a high affinity (extended) conformation. The differentiating characteristic of the two conformations is the interdomain angle between the lectin and the EGF-like domain.

Methods

Using molecular dynamics (MD) simulations we observed that in the absence of tensile force E-selectin undergoes spontaneous switching between the two conformational states at equilibrium. A single amino acid substitution at residue 2 (serine to tyrosine) on the lectin domain favors the extended conformation.

Results

Steered molecular dynamics (SMD) simulations of E-selectin and PSGL-1 in conjunction with experimental cell adhesion assays show a longer binding lifetime of E-selectin (S2Y) to PSGL-1 compared to wildtype protein.

Conclusions

The findings in this study advance our understanding into how the structural makeup of E-selectin allosterically influences its adhesive dynamics.
They ought to do it too: Understanding effects of social information on donation behavior and mood
Authors: van Teunenbroek Claire , Bekkers René , Beersma Bianca
Published: February 2021

Social information, providing potential donors with information about the donation amount given by earlier donors, is often applied as an intervention in online donation contexts. It has been suggested that social information informs others about the most common (descriptive norm) or appropriate (injunctive norm) behavior, and that these perceived social norms explain its effects. We present evidence from a preregistered online experiment testing to what extent perceived social norms mediate effects of social information on charitable giving. In addition, we examine whether social information affects donors’ moods. A positive mood after donating is important to avoid negative side effects of a nudge like social information. We argue that social information increases social pressure to donate in a certain way and therefore decreases donors’ moods. In an experiment among British citizens (n = 1029), we manipulated descriptive and injunctive social information. We show that injunctive social information, mentioning the appropriate donation amount, increases donation amounts (10%) and donors’ moods (10%). Contrary to earlier research, merely stating descriptive social information did not affect the donation behavior or mood. We found no evidence that social information affects giving behavior or mood via perceived social norms. Our findings how different types of social information affect charitable giving are important for fundraisers or policy makers aiming to increase charitable behavior.
Digital image processing methods for the evaluation of optical anisotropy effects in tempered architectural glass using photoelastic measurements
Authors: Dix S. , Müller P. , Schuler C. , Kolling S. , Schneider J.
Published: February 2021

In the present paper, optical anisotropy effects in architectural glass are evaluated using digital image processing. Hereby, thermally toughened glass panes were analyzed quantitatively using a circular polariscope. Glass subjected to externally applied stresses or residual stresses becomes birefringent. Polarized light on birefringent materials causes interference colors (iridescence), referred to as anisotropies, which affect the optical appearance of glass panes in building envelopes. Thermally toughened glass, such as toughened safety glass or heat strengthened glass, show these iridescences due to thermally induced residual stress differences. RGB-photoelastic full-field methods allow the quantitative measurement of anisotropies, since the occurring interference colors are related to the measured retardation values. By calibrating the circular polariscope, retardation images of thermally toughened glass panes are generated from non-directional isochromatic images using computer algorithms. The analysis of the retardation images and the evaluation of the anisotropy quality of the glass is of great interest in order to detect and sort out very low quality glass panes directly in the production process. Therefore, in this paper retardation images are acquired from different thermally toughened glass panes then different image processing methods are presented and applied. It is shown that a general definition of exclusion zones, e.g. near edges is required prior to the evaluation. In parallel, the limitations in the application of first-order statistical and threshold methods are presented. The intend of the investigation is the extension of the texture analysis based on the generation of Grey Level Co-occurrence Matrices, where the spatial arrangement of the retardation values is considered in the evaluation. For the first time, the results of textural features of different glass pane formats could be compared using reference areas and geometry factors. By reduction of the original image size, the computation time of textural analysis algorithms could be remarkably speeded up, while the textural features remained the same. Finally, the knowledge gained from these investigations is used to determine uniform texture features, which also includes the pattern of anisotropy effects in the evaluation of thermally toughened glass. Together with a global evaluation criterion this can now be implemented in commercial anisotropy measurement systems for quality control of tempered architectural glass.
Wirklichkeit und Unwirklichkeit bei Georg Trakl
Authors: Hillenbrand Rainer
Published: February 2021

Trakl konfrontiert ein materialistisches und ein idealistisches Wirklichkeitskonzept, um die Alltagsrealität als defizient zu kritisieren und auf poetische Weise eine geistige Gegenwirklichkeit orphischer Innerlichkeit zu gewinnen. Er benutzt dazu in Anlehnung an antike und christliche Vorbilder eine traditionelle Bildlichkeit, wonach der Tod als Schattenwelt, das Leben als Traum oder Theaterspiel erscheint, und eine in sich stimmige Symbolik. Zuletzt aber scheitert auch diese rein subjektive Sinnsuche der Erinnerung an bessere Zeiten an der unheilbaren Sinnlosigkeit der sozialen und kulturellen Gegenwart.
Baroque Music in Post-War Cinema
Authors: Greig Donald
Published: February 2021

Studies of pre-existing music in narrative cinema often focus on a single film, composer or director. The approach here adopts a wider perspective, placing a specific musical repertoire - baroque music - in the context of its reception to explore its mobilisation in post-war cinema. It shows how various revivals have shaped musical fashion, and how cinema has drawn on resultant popularity and in turn contributed to it. Close analyses of various films raise issues of baroque musical style and form to question why eighteenth-century music remains an exception to dominant film-music discourses. Account is taken of changing modern performance practice and its manifestation in cinema, particularly in the biopic. This question of the reimagining of baroque repertoire leads to consideration of pastiches and parodies to which cinema has been particularly drawn, and subsequently to the role that neobaroque music has played in more recent films.
Entropies and volume growth of unstable manifolds
Authors: ZANG YUNTAO
Published: February 2021

Let f be a
$C^2$
diffeomorphism on a compact manifold. Ledrappier and Young introduced entropies along unstable foliations for an ergodic measure

$\mu $
. We relate those entropies to covering numbers in order to give a new upper bound on the metric entropy of

$\mu $
in terms of Lyapunov exponents and topological entropy or volume growth of sub-manifolds. We also discuss extensions to the

$C^{1+\alpha },\,\alpha>0$
, case.
Air contamination of households versus hospital inpatient rooms occupied by severe acute respiratory coronavirus virus 2 (SARS-CoV-2)–positive patients
Authors: Munoz-Price L. Silvia , Rivera Frida , Ledeboer Nathan
Published: February 2021

The household setting has some of the highest coronavirus disease 2019 (COVID-19) secondary-attack rates. We compared the air contamination in hospital rooms versus households of COVID-19 patients. Inpatient air samples were only positive at 0.3 m from patients. Household air samples were positive even without a COVID-19 patient in the proximity to the air sampler.
Response of tertiary addictions services to opioid dependence during the COVID-19 pandemic
Authors: Hennigan K. , Corrigan N. , Killeen N. , Scully M. , Keenan E.
Published: February 2021

The emergence of the COVID-19 pandemic has presented the addiction services with an unprecedented set of challenges. Opioid users are particularly vulnerable because of their high level of pre-existing health problems and lifestyle factors. In order to minimise their risks to self and to others in the current Covid-19 crisis, addiction services sought to urgently identify vulnerable individuals, and induct them into opioid substitution treatment (OST) promptly. Additionally, several guidelines were created and regularly updated by the health and safety executive (HSE) for any healthcare staff working with opioid users. These include guidance documents, to facilitate prompt induction of patients onto the OST programme, the prescribing of naloxone to all patients at risk of overdose, eConsultation, medication management for those in self-isolation, and the delivery of injecting equipment. The guidance documents and resources will provide a template for a new way of working for the sector during these challenging times and into the future.