bluuebunny/crossref_metadata_2025 huggingface dataset:
µPIV measurement of the 3D velocity distribution of Taylor droplets moving in a square horizontal channel
Authors: Mießner Ulrich , Helmers Thorben , Lindken Ralph , Westerweel Jerry
Published: May 2020

This paper presents a µPIV measurement of the 3D2C velocity distribution of Taylor droplets moving in a square horizontal microchannel at Ca$$_{\mathrm {c}} = 0.005$$c=0.005 and Re$$_{\mathrm {c}} = 0.051$$c=0.051. We reconstruct the third velocity component and present an accuracy assessment of the reconstruction based on a volume flow balance of the 3D3C velocity field. The velocity field allows the investigation of the 3D flow features such as stagnation regions and the shear rate distribution. The maximum shear rate is located at the entrances and exits of the wall films and at the corner flow (gutter) bypassing the Taylor droplet. The regions of high strain correspond to the cap positions of the Taylor droplets. An experimental data set allows visualization of the streamlines of the velocity distribution on the interface of a Taylor droplet and to directly relate it to the main and secondary vortices of the droplet phase velocity field. The measurement data are provided as a digital resource for the validation of numerical simulation or further assessment.

Graphic abstract
Full-field analysis of gas flow within open-cell foams: comparison of micro-computed tomography-based CFD simulations with experimental magnetic resonance flow mapping data
Authors: Sadeghi Mehrdad , Mirdrikvand Mojtaba , Pesch Georg R. , Dreher Wolfgang , Thöming Jorg
Published: May 2020

Pattern of fluid flow through open-cell foams is important because of its influence on the performance of processes such as filtration, adsorption and heterogeneous catalysis that make use of such foams. So far, however, the experimental verification of velocity profiles obtained by computational fluid dynamics (CFD) simulation was insufficient. Here, the effect of morphology of ceramic foams on local gas flow patterns is observed via the noninvasive magnetic resonance velocimetry (MRV) technique. In order to cross-validate the simulations with the experimental flow mapping results, micro-computed tomography (µCT) data of the entire foams were used for generating the computational network required for 3D CFD simulations of velocity fields within the pores. The results of CFD simulations and MRV measurements of gas flow showed a remarkable agreement with deviations mainly below 10 percent if the whole foam structure was utilized in CFD simulations. The qualitative and quantitative agreement between CFD and MRV results underlines the reliability of CFD simulations that are based on µCT data and underpins the capability of NMR-based measurements for in situ velocity measurements.

Graphic abstract
Biomarkers in newborns with hypoxic-ischemic encephalopathy treated with therapeutic hypothermia
Authors: Michniewicz Barbara , Szpecht Dawid , Sowińska Anna , Sibiak Rafał , Szymankiewicz Marta , Gadzinowski Janusz
Published: May 2020

Purpose

The aim of the presented study was to evaluate the differences between selected biochemical markers in infants with moderate or severe hypoxic-ischemic encephalopathy (HIE) and their impact on patient prognosis.

Methods

A total of 57 cooled newborns were divided into groups according to Sarnat staging of HIE (A, moderate vs. B, severe). The differences between groups were evaluated depending on the mode of delivery, pregnancy and labor complications, gestational age at birth, birth weight, and Apgar score at 1.3 and 5 min. The differences in biochemical biomarkers of HIE (pH, base excess, serum lactate) as well as biomarkers of hepatic injury (aspartate transaminase, (AST), alanine transaminase (ALT), prothrombin time (PT), and activated partial thromboplastin time (APTT)), kidney failure (creatinine, urea), myocardial injury (troponin T (TnT)), levels of fibrinogen, and platelet counts were also examined. Univariate Kaplan-Meier method was used for survival analyses.

Results

The biomarker levels in severe HIE newborns compared with moderate were as follows: pH (7.10 vs. 6.99), serum lactate (22.50 vs. 17.00 mg/dL), AST (109.50 vs. 270.55 IU/L), ALT (27.30 vs. 108.05 IU/L), PT (17.00 vs. 44.20 s), APTT (47.75 vs. 47.90 s), TnT (0.22 vs. 0.85 ng/mL), creatinine (0.68 vs. 1.15 mg/dL), urea (44.55 vs. 73.30 mg/dL), and fibrinogen (1.65 vs. 1.90 mg/dL). Survival analyses showed significantly reduced survival for severe HIE infants (75%) vs. moderate HIE (100%).

Conclusion

In conclusion, the severity of HIE can be evaluated based on selected markers; however, their levels do not correspond with future prognosis of newborns.
The hirudin-like factors HLF3 and HLF4—hidden hirudins of European medicinal leeches
Authors: Müller Christian , Lukas Phil , Sponholz Dana , Hildebrandt Jan-Peter
Published: May 2020

The hirudin-like factors 3 (HLF3) and 4 (HLF4) belong to a new class of leech-derived factors and are present in specimens of the three European medicinal leeches, Hirudo medicinalis, Hirudo verbana, and Hirudo orientalis, respectively. Here we describe the functional analysis of natural and synthetic variants of HLF3 and HLF4. Whereas the natural variants display only very low or no detectable anti-coagulatory activities, modifications within the N-termini in combination with an exchange of the central globular domain have the potency to greatly enhance the inhibitory effects of respective HLF3 and HLF4 variants on blood coagulation. Our results support previous observations on the crucial importance of all parts (both the N- and C-termini as well as the central globular domains) of hirudin and HLF molecules for thrombin inhibition.
A dynamical view of nonlinear conjugate gradient methods with applications to FFT-based computational micromechanics
Authors: Schneider Matti
Published: May 2020

For fast Fourier transform (FFT)-based computational micromechanics, solvers need to be fast, memory-efficient, and independent of tedious parameter calibration. In this work, we investigate the benefits of nonlinear conjugate gradient (CG) methods in the context of FFT-based computational micromechanics. Traditionally, nonlinear CG methods require dedicated line-search procedures to be efficient, rendering them not competitive in the FFT-based context. We contribute to nonlinear CG methods devoid of line searches by exploiting similarities between nonlinear CG methods and accelerated gradient methods. More precisely, by letting the step-size go to zero, we exhibit the Fletcher–Reeves nonlinear CG as a dynamical system with state-dependent nonlinear damping. We show how to implement nonlinear CG methods for FFT-based computational micromechanics, and demonstrate by numerical experiments that the Fletcher–Reeves nonlinear CG represents a competitive, memory-efficient and parameter-choice free solution method for linear and nonlinear homogenization problems, which, in addition, decreases the residual monotonically.
Dissecting innovative trend analysis
Authors: Serinaldi Francesco , Chebana Fateh , Kilsby Chris G.
Published: May 2020

Investigating the nature of trends in time series is one of the most common analyses performed in hydro-climate research. However, trend analysis is also widely abused and misused, often overlooking its underlying assumptions, which prevent its application to certain types of data. A mechanistic application of graphical diagnostics and statistical hypothesis tests for deterministic trends available in ready-to-use software can result in misleading conclusions. This problem is exacerbated by the existence of questionable methodologies that lack a sound theoretical basis. As a paradigmatic example, we consider the so-called Şen’s ‘innovative’ trend analysis (ITA) and the corresponding formal trend tests. Reviewing each element of ITA, we show that (1) ITA diagrams are equivalent to well-known two-sample quantile-quantile (q–q) plots; (2) when applied to finite-size samples, ITA diagrams do not enable the type of trend analysis that it is supposed to do; (3) the expression of ITA confidence intervals quantifying the uncertainty of ITA diagrams is mathematically incorrect; and (4) the formulation of the formal tests is also incorrect and their correct version is equivalent to a standard parametric test for the difference between two means. Overall, we show that ITA methodology is affected by sample size, distribution shape, and serial correlation as any parametric technique devised for trend analysis. Therefore, our results call into question the ITA method and the interpretation of the corresponding empirical results reported in the literature.
Review and reflections about pulsatile ventricular assist devices from history to future: concerning safety and low haemolysis—still needed
Authors: Köhne Inge
Published: May 2020

Since the first use of a ventricular assist device in 1963 many extracorporeal and implantable pulsatile blood pumps have been developed. After the invention of continuous flow blood pumps the implantable pulsatile pumps are not available anymore. The new rotary pumps spend a better quality of life because many of the patients can go home. Nevertheless, the extracorporeal pulsatile pumps have some advantages. They are low-cost systems, produce less haemolysis and heart-recovery can be tested easily. Pump failure is easy to realize because the pumps can be observed visually. Pump exchange can be done easily without any chirurgic surgery. As volume displacement pumps they can produce high blood pressure, so they are the only ones suitable for pediatric patients. Therefore, they are indispensable for clinical use today and in the future. In this work, nearly all pulsatile blood pumps used in clinical life are described.
Propensity score matching/reweighting analysis comparing intravenous golimumab to infliximab for ankylosing spondylitis using data from the GO-ALIVE and ASSERT trials
Authors: Gensler L. S. , Chakravarty S. D. , Cameron Chris , Peterson S. , Spin P. , Kafka S. , Nair S. , Deodhar A.
Published: May 2020

Objective

To compare the relative efficacy of intravenous golimumab (GOL IV) and infliximab (IFX) for active ankylosing spondylitis (AS).

Methods

Propensity score (PS) methods were used to compare the efficacy of GOL IV 2 mg/kg and IFX 5 mg/kg using individual patient data (IPD) from the active arms of the phase 3 GO-ALIVE and ASSERT studies. Outcomes included the proportion of patients with a ≥ 20% improvement in the Assessment of Spondyloarthritis International Society Criteria (ASAS20), change from baseline in Bath Ankylosing Spondylitis Functional Index (BASFI) score, and change from baseline in C-reactive protein (CRP) levels from weeks 4–52.

Results

Before matching, 105 patients were treated with GOL IV and 201 patients were treated with IFX. After matching on all covariates, 118 patients were included in the ASAS20 analysis, 96 in the BASFI analysis, and 160 in the CRP analysis. After matching, GOL IV showed significantly greater improvement in ASAS20 response than IFX for weeks 28–44 (e.g., OR = 9.05 [95% CI 1.62–50.4] at week 44) and was comparable in change from baseline in BASFI scores and CRP levels to IFX at all time points. Results were robust for inclusion of different sets of covariates in scenario analyses.

Conclusions

This is the first analysis of its kind to leverage clinical trial data to compare two biologics using PS methods in the treatment of active AS. Overall, GOL IV was associated with greater improvement in ASAS20 response than IFX in patients with AS at 28, 36, and 44 weeks of follow-up.

Key Points• Although intravenous golimumab (GOL IV) and infliximab (IFX) are the only two IV-based tumor necrosis factor (TNF) inhibitors with demonstrated phase 3 clinical efficacy in patients with ankylosing spondylitis (AS), no study has evaluated their comparative efficacy in a head-to-head trial.• Propensity score matching was used to derive indirect treatment comparisons of GOL IV and IFX for ≥ 20% in the Assessment of Spondyloarthritis International Society Criteria (ASAS20), change in Bath Ankylosing Spondylitis Functional Index (BASFI), and change in C-reactive protein (CRP) using individual patient data from the GO-ALIVE and ASSERT phase 3 trials.• Propensity score matched indirect comparisons showed improved relative efficacy of GOL IV compared to IFX; after matching for up to 16 baseline covariates, GOL IV was associated with significantly greater odds of ASAS20 response at weeks 28, 36, and 44 than IFX as well as equivalent changes from baseline in BASFI and CRP.• This novel application of propensity score matching using data from phase 3 trials, the first analysis of its kind in AS, allowed adjustment for important imbalances in prognostic factors between trials to generate estimates of comparative efficacy between GOL IV and IFX in the absence of a head-to-head trial between these treatments.
Analysis of Drug Effects on iPSC Cardiomyocytes with Machine Learning
Authors: Juhola Martti , Penttinen Kirsi , Joutsijoki Henry , Aalto-Setälä Katriina
Published: May 2020

Patient-specific induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) offer an attractive experimental platform to investigate cardiac diseases and therapeutic outcome. In this study, iPSC-CMs were utilized to study their calcium transient signals and drug effects by means of machine learning, a central part of artificial intelligence. Drug effects were assessed in six iPSC-lines carrying different mutations causing catecholaminergic polymorphic ventricular tachycardia (CPVT), a highly malignant inherited arrhythmogenic disorder. The antiarrhythmic effect of dantrolene, an inhibitor of sarcoplasmic calcium release, was studied in iPSC-CMs after adrenaline, an adrenergic agonist, stimulation by machine learning analysis of calcium transient signals. First, beats of transient signals were identified with our peak recognition algorithm previously developed. Then 12 peak variables were computed for every identified peak of a signal and by means of this data signals were classified into different classes corresponding to those affected by adrenaline or, thereafter, affected by a drug, dantrolene. The best classification accuracy was approximately 79% indicating that machine learning methods can be utilized in analysis of iPSC-CM drug effects. In the future, data analysis of iPSC-CM drug effects together with machine learning methods can create a very valuable and efficient platform to individualize medication in addition to drug screening and cardiotoxicity studies.
The role of the understory in litter DOC and nutrient leaching in boreal forests
Authors: Hensgens Geert , Laudon Hjalmar , Peichl Matthias , Gil Itziar Aguinaga , Zhou Quan , Berggren Martin
Published: May 2020

Dissolved organic carbon (DOC) derived from plant litter plays an important role in the ecosystem carbon balance and soil biogeochemistry. However, in boreal coniferous forests no integrated understanding exists of how understory vegetation contributes to litter leaching of DOC, nitrogen (N) and phosphorus (P) with different bioavailability at the forest stand level. We characterized water extractable leachates from fresh and decayed litter of dominant canopy and understory sources in a boreal coniferous forest, in order to explore the contribution of understory vegetation as a source of both total and bioavailable forms of DOC, N and P. Recently produced litter from deciduous species (including Vaccinium myrtillus) yielded the highest amounts of DOC. However, this leaching potential decreased exponentially with mass loss through litter decay. The DOC lability generally showed little interspecific variation, although wood derived DOC was more recalcitrant. Lability decreased progressively with litter aging. Water extractable nutrients increased proportionally with DOC, and roughly a quarter (N) or half (P) had directly bioavailable inorganic forms. Scaled to annual litterfall at the forest stand, understory vegetation contributed ~ 80% of the water extractable DOC and nutrients from fresh litter, with > 60% coming from Vaccinium myrtillus alone. However, as litter decomposes, the data suggest a lower leaching potential is maintained with a larger contribution from needle, wood and moss litter. Our study shows that understory vegetation, especially V. myrtillus, is a key driver of litter DOC and nutrient leaching in boreal coniferous forests.
Spatiotemporal Dynamics of Single and Paired Pulse TMS-EEG Responses
Authors: de Goede Annika A. , Cumplido-Mayoral Irene , van Putten Michel J. A. M.
Published: May 2020

For physiological brain function a particular balance between excitation and inhibition is essential. Paired pulse transcranial magnetic stimulation (TMS) can estimate cortical excitability and the relative contribution of inhibitory and excitatory networks. Combining TMS with electroencephalography (EEG) enables additional assessment of the spatiotemporal dynamics of neuronal responses in the stimulated brain. This study aims to evaluate the spatiotemporal dynamics and stability of single and paired pulse TMS-EEG responses, and assess long intracortical inhibition (LICI) at the cortical level. Twenty-five healthy subjects were studied twice, approximately one week apart. Manual coil positioning was applied in sixteen subjects and robot-guided positioning in nine. Both motor cortices were stimulated with 50 single pulses and 50 paired pulses at each of the five interstimulus intervals (ISIs): 100, 150, 200, 250 and 300 ms. To assess stability and LICI, the intraclass correlation coefficient and cluster-based permutation analysis were used. We found great resemblance in the topographical distribution of the characteristic TMS-EEG components for single and paired pulse TMS. Stimulation of the dominant and non-dominant hemisphere resulted in a mirrored spatiotemporal dynamics. No significant effect on the TMS-EEG responses was found for either stimulated hemisphere, time or coil positioning method, indicating the stability of both single and paired pulse TMS-EEG responses. For all ISIs, LICI was characterized by significant suppression of the late N100 and P180 components in the central areas, without affecting the early P30, N45 and P60 components. These observations in healthy subjects can serve as reference values for future neuropsychiatric and pharmacological studies.
Angiography-based quantitative coronary contrast-flow ratio measurements correlate with myocardial ischemia assessed by stress MRI
Authors: Lenk Karsten , Schwarzbach Valentin , Antoniadis Marios , Blum Maximilian , Zeynalova Samira , Hagendorff Andreas , Leistner David , Landmesser Ulf , Lavall Daniel , Laufs Ulrich
Published: May 2020

Contrast-flow quantitative flow ratio (cQFR) is a new technology for quantitative evaluation of coronary stenosis using computational fluid dynamics based on angiograms. The aim of this study was to assess the sensitivity and specificity of cQFR to detect myocardial ischemia using stress magnetic resonance imaging (MRI) as a reference standard. Patients who received stress MRI and coronary angiography were selected from the hospital database. Relevant ischemia on stress MRI was defined as a perfusion deficit in ≥ 2 of 16 segments. cQFR was quantitated based on 3-dimensional quantitative coronary angiography using QAngio XA3D1.1 software by two blinded and independent investigators. A cQFR of ≤ 0.80 was considered abnormal. Among 87 patients 230 vessels met the criteria for full analysis by cQFR (88%). In vascular territories with a significant perfusion deficit, cQFR was significantly lower compared to areas with normal perfusion (0.72 (0.62–0.78) vs. 0.96 (0.89–0.99); p < 0.001). The sensitivity of cQFR in detecting significant epicardial stenoses of coronary vessels with documented ischemia in stress MRI was 81% (68–90%), the specificity was 88% (82–92%). Diameter stenoses (DS) and area stenoses (AS) in vessels with positive stress MRI were significantly higher than in vessels without ischemia (DS 59.1% (49.4–68.4%) vs. 34.8% (27.1–46.1%) p < 0.001; AS 75.6% (63.0–85.2%) vs. 45.0% (30.8–63.6%), p < 0.001). The analysis reveals a high correlation between coronary stenosis measured by cQFR and ischemic areas detected by stress MRI. The data set the stage to plan randomized studies assessing cQFR measurements with regard to clinical outcomes.
Revisiting Gilbert’s known-key distinguisher
Authors: Grassi Lorenzo , Rechberger Christian
Published: May 2020

Known-key distinguishers have been introduced by Knudsen and Rijmen in 2007 to better understand the security of block ciphers in situations where the key can not be considered to be secret, i.e. the “thing between secret-key model and hash function use-cases”. Trying to find a rigorous model to fit this intuition is still ongoing. The most recent advance by Gilbert (Asiacrypt 2014) describes a new model that—even if it is well justified—seemingly does not match this intuition. AES is often considered as a target of such analyses, simply because AES or its building blocks are used in many settings that go beyond classical encryption. Consider AES-128. Results in the secret-key model cover up to 6 rounds, while results in the chosen-key model reach up to 9 rounds. Gilbert however showed a result in the known-key model that goes even further, covering 10 rounds. Does it mean that the use cases corresponding to the cryptanalysis of hash-function use-cases are inherently less efficient, or is it rather an artifact of the new model? In this paper we give strong evidence for the latter. In Gilbert’s work, two types of arguments or rather conjectures are put forward suggesting that the new model is meaningful. Firstly that the number of “extension rounds” due to the new model is limited to two. And secondly that only a distinguisher that exploits the uniform distribution property can be extended in such way. We disprove both conjectures and arrive at the following results: First, we are also able to show that more than two extension rounds are possible. As a result of this, we describe the first known-key distinguishers on 12 rounds of AES that fit into Gilbert’s model. The second conjecture is disproven by showing that the technique proposed by Gilbert can also be used to extend a known-key distinguisher based on another property: truncated differentials. A potential conclusion of this work would be that the counter-intuitive gap between Gilbert’s known-key model and the chosen-key model is wider than initially thought. We however conclude that results in Gilbert’s model are due to an artifact in the model. To remedy this situation, we propose a refinement of the known-key model which restores its original intent to fit the original intuition.
Objectives, design and main findings until 2020 from the Rotterdam Study
Authors: Ikram M. Arfan , Brusselle Guy , Ghanbari Mohsen , Goedegebure André , Ikram M. Kamran , Kavousi Maryam , Kieboom Brenda C. T. , Klaver Caroline C. W. , de Knegt Robert J. , Luik Annemarie I. , Nijsten Tamar E. C. , Peeters Robin P. , van Rooij Frank J. A. , Stricker Bruno H. , Uitterlinden André G. , Vernooij Meike W. , Voortman Trudy
Published: May 2020

The Rotterdam Study is an ongoing prospective cohort study that started in 1990 in the city of Rotterdam, The Netherlands. The study aims to unravel etiology, preclinical course, natural history and potential targets for intervention for chronic diseases in mid-life and late-life. The study focuses on cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric, dermatological, otolaryngological, locomotor, and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. Since 2016, the cohort is being expanded by persons aged 40 years and over. The findings of the Rotterdam Study have been presented in over 1700 research articles and reports. This article provides an update on the rationale and design of the study. It also presents a summary of the major findings from the preceding 3 years and outlines developments for the coming period.
The development of multicultural effectiveness in international student mobility
Authors: Zimmermann Julia , Greischel Henriette , Jonkmann Kathrin
Published: May 2020

International student mobility (ISM) is an important educational means to increase students’ multicultural effectiveness and their (international) job market potential. In the present study, we investigated ISM effects by addressing the following three research questions: First, how do future sojourners differ from control students in terms of their pre-departure multicultural effectiveness? Second, how does ISM affect the development of multicultural effectiveness above and beyond effects of students’ demographic characteristics, their cultural and educational background, and their previous international mobility experiences? And third, do any of these variables moderate ISM development effects and thus help to explain who benefits most from ISM? We used a sample of N = 3070 students at German higher education institutions who were assigned to three groups (i.e., control students with no mobility plans, present sojourners who participated in ISM during the study period, and a waiting group of future sojourners who participated in ISM in the semester sequencing the study period). The analyses with (moderated) latent change models showed substantially higher pre-departure multicultural effectiveness in present and future sojourners compared with control students as well as positive effects of ISM on the development of multicultural effectiveness. The strongest effects were observed amongst students without previous international mobility experiences. Theoretical implications for the understanding of adaptive development in a globalized world as well as practical inferences for ISM outreach and recruitment strategies are discussed.
Drug Abuse Amongst Adolescent Learners in Townships
Authors: Sedibe Mabatho , Hendricks Nellie Gloria Patricia
Published: May 2020

The study explored the experiences of adolescent learners regarding drug abuse in previously disadvantaged townships in South Africa. A phenomenological research paradigm was employed, and an inductive research approach was implemented. The study followed a qualitative research design focusing on interviews and document analysis as data collection methods. Purposive sampling was done and one-on-one interviews with Life Orientation (LO) teachers in two Gauteng secondary schools were conducted as well as three Non-Governmental Organisations (NGO’s) and Non-Profit Organisations (NPO’s) from different organisations. Focus group interviews were conducted with adolescent learners in two Gauteng secondary schools. I further utilised an inductive content analysis using open coding and axial coding to decipher information gathered from interviews conducted with participants.The study leaned on two theoretical frameworks which include Bronfenbrenner’s Nested System and Erikson’s Eight Stages of Psychosocial Development. The findings indicated that adolescent learners get involved in the use of drugs due to their lack of identity formation and the need to belong. It was also discovered that adolescent learners did not master the adolescence stage successfully, hence getting involved in the use of drugs.
Access and allocation: the role of large shareholders and investors in leaving fossil fuels underground
Authors: Gupta Joyeeta , Rempel Arthur , Verrest Hebe
Published: May 2020

An under-researched story is how large shareholders (e.g. Pension Funds) and investors (e.g. Export Credit Agencies) whose investments in fossil fuels may amount to trillions of dollars are implementing the Paris Agreement on Climate Change and in particular leaving fossil fuels underground (LFFU). Hence, this paper addresses the question: What arguments are used by shareholders and investors in making their financial flows consistent with LFFU, and what do these arguments imply for: access to fulfilling needs; allocation of related resources, responsibilities and risks; and, the right to (sustainable) development? This paper identifies the different arguments used and clusters them into five investor/shareholder scenarios. It assesses these scenarios using the inclusive (access and allocation) development framework. We find that there is prima facie evidence that fossil fuels and associated infrastructure are doomed to become obsolete and hence stranded, which poses a series of risks for (potential) investors and various stakeholders. Three of the five identified scenarios indicate that Pension Funds and Export Credit Agencies may transfer their risks associated with fossil fuel resources, assets and/or related knowledge to developing countries justified by the latter’s Right to Development. Such transfers have negative access and allocation impacts—creating, inter alia, a fossil fuel infrastructure and path dependency in the South and amounting to a de facto transfer of a carbon budget along with carbon dependency and related debt to the Global South.
Scaffolding Children’s Production of Representations Along the Three Years of ECE: a Longitudinal Study
Authors: Monteira Sabela F. , Jiménez-Aleixandre María Pilar , Siry Christina
Published: May 2020

We report a longitudinal study carried out along 3 years in an early childhood education (ECE) classroom in which we examined children’s (aged 3–6) engagement with science representations. The research questions are as follows: (1) How do children’s science representations develop from ECE1 to ECE3? (2) What are the features and affordances of the teacher’s scaffolding of the production of science representations and how is it facilitated from the first to the third year of ECE? The participants were 21 children and their teacher. The group was involved in long-term science projects that lasted for 5 months each. Sessions (N = 30) were recorded and children’s drawings (N = 487) gathered. Data were analyzed using discourse and content analyses, coupled with an analysis of the intensity of scaffolding. The results indicate that children’s representations of science phenomena became more complex along several dimensions. We have identified teacher’s scaffolding strategies which supported children’s increasing autonomy in producing representations. Implications are drawn for teaching science at the ECE level as well as for further research.
Temporal issues in life cycle assessment—a systematic review
Authors: Lueddeckens Stefan , Saling Peter , Guenther Edeltraud
Published: May 2020

Purpose

Case studies on life cycle assessments frequently admit that the precision of their outcome could be undermined due to temporal issues, though they usually refrain from offering much more detail. In addition, available overview papers and reviews on problems and challenges in LCA do not address the whole range of temporal issues. As those are major sources of inaccuracies and influence each other, it is important to get a clear picture of them, to close gaps in definitions, to systemize temporal issues, and to show their interdependencies and proposed solutions. In order to identify the state of science on those questions, we conducted a systematic literature review.

Methods

We first systematized temporal issues based on ISO 14040ff and divided them into six types: time horizon, discounting, temporal resolution of the inventory, time-dependent characterization, dynamic weighting, and time-dependent normalization. Building on that, we identified suitable search terms and developed an analysis grid for the content analysis. We included only methodological papers and case studies with original findings on solutions for temporal issues. Bibliographic data, impact types, industrial fields, and methodological contributions were analyzed.

Results and discussion

Literature differentiates between different types of time horizons. There is one for the whole assessment, defined in goal and scope, one for the life cycle inventory, and one for the impact characterization. Setting a time horizon for the assessment is regarded as equivalent to the application of discounting. Both very long and very short time horizons of the assessment are not practical depending on the topic assessed in the LCA. Very short ones would offend the principle of intergenerational equality, while very long ones would marginalize short-term actions and thereby reduce incentives to act. There is consensus in the literature that temporally differentiated life cycle inventories and time-dependent, or at least time horizon dependent, characterization improve the accuracy of LCA. Generally, dynamic life cycle assessments are attractive for companies because the calculation results are not only more accurate but are often also lower than in static life cycle assessments.

Conclusion

The main questions where we did not find consensus are the issue of the length of the time horizon of the assessment and the issue of discounting. Those are regarded as subjective and are encountered with sensitivity or scenario analysis. Further investigations should be taken for a better understanding of this issue and for concrete solutions because their influence on the results of life cycle assessments is often fundamental.
Targeting Toll-like receptor 4 with CLI-095 (TAK-242) enhances the antimetastatic effect of the estrogen receptor antagonist fulvestrant on non-small cell lung cancer
Authors: Fan S. , Liao Y. , Qiu W. , Li L. , Li D. , Cao X. , Ai B.
Published: May 2020

Purpose

Estrogen plays a critical role in the invasiveness and metastasis of non-small cell lung cancer (NSCLC) through estrogen receptor β (ERβ). However, the antimetastatic effect of the ERβ antagonist fulvestrant was still limited in NSCLC patients. Recently, Toll-like receptor 4 (TLR4) signaling was implicated in NSCLC metastasis. Our present study aimed to evaluate the synergistic antimetastatic effect of a combination of fulvestrant and the TLR4-specific inhibitor CLI-095 (TAK-242) on human NSCLC cells.

Methods

The expression levels of ERβ and TLR4 were detected by immunohistochemical (IHC) analysis of 180 primary NSCLC and 30 corresponding metastatic lymph node samples. The association between ERβ and TLR4 expression was analyzed. The aggressiveness of NSCLC cells treated with fulvestrant, CLI-095 or the drug combination and formation status of their invadopodia, invasion-associated structures, were investigated. The protein levels in NSCLC cells in different groups were determined by Western blot and immunofluorescence analyses.

Results

Here, a positive correlation between ERβ and TLR4 expression was observed in both primary NSCLC tissue (Spearman’s Rho correlation coefficient = 0.411, p < 0.001) and metastatic lymph node tissue (Spearman’s Rho correlation coefficient = 0.374, p = 0.009). The protein levels of ERβ in NSCLC cell lines were decreased by fulvestrant, and this suppressive effect was significantly enhanced when fulvestrant was combined with CLI-095 (p < 0.05). Both the migration and invasion of NSCLC cells were suppressed by fulvestrant or CLI-095 alone, and the combination of fulvestrant + CLI-095 showed the strongest inhibitory effect (p < 0.05). In addition, the results demonstrated that CLI-095 also helped fulvestrant restrict the formation and function of invadopodia in NSCLC cells (p < 0.05).

Conclusions

Collectively, our study results suggested that CLI-095 enhances the antimetastatic effect of fulvestrant on NSCLC and provided support for further investigation of the antitumor activity of combined therapy with antiestrogen and anti-TLR4 agents in the clinic.
Viscous flow simulations through multi-lobe progressive cavity pumps
Authors: El-Abd F. M. , Wahba E. M. , Adam I. G.
Published: May 2020

Computational fluid dynamics (CFD) simulations of multi-lobe progressive cavity (PC) pumps are limited in the literature due to the geometric complexity of the pump, which places numerous restrictions on the grid generation process. The present study attempts to alleviate such restrictions by developing a detailed numerical procedure for the numerical simulations of multi-lobe progressive cavity pumps. The profile equations for the multi-lobe configuration at any section at each instant of rotation are presented. A structured grid generation method is developed to generate mesh files required for CFD simulations of multi-lobe PC pumps. Results from the present procedure are validated against single-lobe PC pump numerical results available in the literature. Finally, a numerical parametric study is carried out to investigate the effect of the number of lobes, the stator pitch, the circular fillet and clearance on the volumetric efficiency of PC pumps with viscous oils.
From specified product tolerance to acceptable material and process scatter: an inverse robust optimization approach
Authors: Nejadseyfi O. , Geijselaers H. J. M. , Atzema E. H. , Abspoel M. , van den Boogaard A. H.
Published: May 2020

Production efficiency in metal forming processes can be improved by implementing robust optimization. In a robust optimization method, the material and process scatter are taken into account to predict and to minimize the product variability around the target mean. For this purpose, the scatter of input parameters are propagated to predict the product variability. Consequently, a design setting is selected at which product variation due to input scatter is minimized. If the minimum product variation is still higher than the specific tolerance, then the input noise must be adjusted accordingly. For example this means that materials with a tighter specification must be ordered, which often results in additional costs. In this article, an inverse robust optimization approach is presented to tailor the variation of material and process noise parameters based on the specified product tolerance. Both robust optimization and tailoring of material and process scatter are performed on the metamodel of an automotive part. Although the robust optimization method facilitates finding a design setting at which the product to product variation is minimized, the tighter product tolerance is only achievable by requiring less scatter of noise parameters. It is shown that the presented inverse approach is able to predict the required adjustment for each noise parameter to obtain the specified product tolerance. Additionally, the developed method can equally be used to relax material specifications and thus obtain the same product tolerance, ultimately resulting in a cheaper process. A strategy for updating the metamodel on a wider (noise) base is presented and implemented to obtain a larger noise scatter while maintaining the same product tolerance.
Extraction of Vehicle Turning Trajectories at Signalized Intersections Using Convolutional Neural Networks
Authors: Abdeljaber Osama , Younis Adel , Alhajyaseen Wael
Published: May 2020

This paper aims at developing a convolutional neural network (CNN)-based tool that can automatically detect the left-turning vehicles (right-hand traffic rule) at signalized intersections and extract their trajectories from a recorded video. The proposed tool uses a region-based CNN trained over a limited number of video frames to detect moving vehicles. Kalman filters are then used to track the detected vehicles and extract their trajectories. The proposed tool achieved an acceptable accuracy level when verified against the manually extracted trajectories, with an average error of 16.5 cm. Furthermore, the trajectories extracted using the proposed vehicle tracking method were used to demonstrate the applicability of the minimum-jerk principle to reproduce variations in the vehicles’ paths. The effort presented in this paper can be regarded as a way forward toward maximizing the potential use of deep learning in traffic safety applications.
Effect of the parameters of weld toe geometry on the FAT class as obtained by means of fracture mechanics-based simulations
Authors: Schork B. , Zerbst Uwe , Kiyak Y. , Kaffenberger M. , Madia M. , Oechsner M.
Published: May 2020

The fracture mechanics-based IBESS approach is applied to the determination of FAT classes of butt welds with crack initiation along the weld toe. The aim is an investigation of the effect of the geometrical parameters toe radius, flank angle, reinforcement and secondary notches such as roughness or undercuts. The influence of these parameters is discussed both individually and in combination; however, excluding statistical distributions of them and the material data. The results, when compared with conventional FAT classes for butt welds, are encouraging with respect to a potential contribution of IBESS to the discussion of more advanced quality criteria for welds. To that purpose, demands for further research are proposed.
Recent Advances in Strain-Induced Piezoelectric and Piezoresistive Effect-Engineered 2D Semiconductors for Adaptive Electronics and Optoelectronics
Authors: Li Feng , Shen Tao , Wang Cong , Zhang Yupeng , Qi Junjie , Zhang Han
Published: May 2020

The development of two-dimensional (2D) semiconductors has attracted widespread attentions in the scientific community and industry due to their ultra-thin thickness, unique structure, excellent optoelectronic properties and novel physics. The excellent flexibility and outstanding mechanical strength of 2D semiconductors provide opportunities for fabricated strain-sensitive devices and utilized strain tuning their electronic and optic–electric performance. The strain-engineered one-dimensional materials have been well investigated, while there is a long way to go for 2D semiconductors. In this review, starting with the fundamental theories of piezoelectric and piezoresistive effect resulted by strain, following we reviewed the recent simulation works of strain engineering in novel 2D semiconductors, such as Janus 2D and 2D-Xene structures. Moreover, recent advances in experimental observation of strain tuning PL spectra and transport behavior of 2D semiconductors are summarized. Furthermore, the applications of strain-engineered 2D semiconductors in sensors, photodetectors and nanogenerators are also highlighted. At last, we in-depth discussed future research directions of strain-engineered 2D semiconductor and related electronics and optoelectronics device applications.
Energy and Latency of Beamforming Architectures for Initial Access in mmWave Wireless Networks
Authors: Barati C. Nicolas , Dutta Sourjya , Rangan Sundeep , Sabharwal Ashutosh
Published: May 2020

Future millimeter-wave systems, 5G cellular or WiFi, must rely on highly directional links to overcome severe pathloss in these frequency bands. Establishing such links requires the mutual discovery of the transmitter and the receiver, potentially leading to a large latency and high energy consumption. In this work, we show that both the discovery latency and energy consumption can be significantly reduced using fully digital front-ends. In fact, we establish that by reducing the resolution of the fully digital front-ends we can achieve lower energy consumption compared to both analog and high-resolution digital beamforming. Since beamforming through analog front-ends allows sampling in only one direction at a time, the mobile device is “on” for a longer time compared to a digital beamformer, which can get spatial samples from all directions in one shot. We show that the energy consumed by the analog front-end can be four to six times more than that of the digital front-ends, depending on the size of the employed antenna arrays. We recognize, however, that using fully digital beamforming post beam discovery, i.e., for data transmission, is not viable from a power consumption standpoint. To address this issue, we propose the use of digital beamformers with low-resolution analog to digital converters (4 bits). This reduction in resolution brings the power consumption to the same level as analog beamforming for data transmissions while benefiting from the spatial multiplexing capabilities of fully digital beamforming, thus reducing initial discovery latency and improving energy efficiency.
Particle concentrations, dispersion modelling and evaluation in southern Sweden
Authors: Rittner Ralf , Gustafsson Susanna , Spanne Mårten , Malmqvist Ebba
Published: May 2020

Health impact assessments of differential air pollution rely on epidemiologically established relationships between concentration levels where people are exposed and adverse health outcomes. To assess air pollution concentrations, land use regression is commonly used. However, an alternative tool is dispersion modelling, where a detailed inventory of pollution sources together with meteorological data drives calculations of compound dispersion. With this, both spatial and temporal variation can be assessed. In this study, we evaluated results of a Gaussian dispersion model applied to an emissions inventory for Scania, the southernmost county in Sweden. The dispersion considered was particulate matter of aerodynamic diameter < 10 µm (PM10), particulate matter of aerodynamic diameter < 2.5 µm (PM2.5) and black carbon (BC) during an 11-year period (2000–2011). Mean concentrations and 95th percentiles expressed in µg/m3 ranged from 10.1 to 12.6 and 16.6 to 20.7 for PM2.5 and from 14.0 to 18.8 and 22.6 to 27.0 for PM10, respectively. Seven monitoring stations were used for evaluation. Correlations (R2) ranged from 0.44 to 0.86 for PM2.5 (mean bias from − 9.0 to 0.1 µg/m3) and from 0.46 to 0.83 for PM10 (mean bias − 6.1 to 3.5 µg/m3). An evaluated database of PM and BC concentrations for Scania is now available for future exposure assessment projects. Calculations were based on a well-known dispersion model with detailed emission data as input. The evaluation showed correlation coefficients for PM in line with previous literature. The data on PM10, PM2.5 and BC concentrations will, therefore, be used in subsequent studies, epidemiological as well as health impact assessments.
Contamination of titanium dental implants: a narrative review
Authors: Dhaliwal Jagjit Singh , David Sheba Rani Nakka , Zulhilmi Nurul Ramizah , Sodhi Dhaliwal Sachinjeet Kaur , Knights Joe , de Albuquerque Junior Rubens Ferreira
Published: May 2020

Contamination of titanium dental implants may lead to implant failure. There are two major types of contaminants: the inorganic and organic contaminants. The inorganic contaminants mostly consist of elements such as calcium, phosphorus, chlorine, sulphur, sodium, silicon, fluorine and some organic carbons. Whereas organic contaminants consist of hydrocarbon, carboxylates, salts of organic acids, nitrogen from ammonium and bacterial cells/byproducts. Contaminants can alter the surface energy, chemical purity, thickness and composition of the oxide layer, however, we lack clinical evidence that contaminations have any effect at all. However, surface cleanliness seems to be essential for implant osseointegration.These contaminants may cause dental implants to fail in its function to restore missing teeth and also cause a financial burden to the patient and the health care services to invest in decontamination methods. Therefore, it is important to discuss the aetiology of dental implant failures. In this narrative review, we discuss two major types of contaminants: the inorganic and organic contaminants including bacterial contaminants. This review also aims to discuss the potential effect of contamination on Ti dental implants.