bluuebunny/crossref_metadata_2025 huggingface dataset:
Complexity vulnerability analysis using symbolic execution
Authors: Luckow Kasper , Kersten Rody , Pasareanu Corina
Published: February 2020

We describe techniques based on symbolic execution for finding software vulnerabilities that are due to algorithmic complexity. Such vulnerabilities allow an attacker to mount denial‐of‐service attacks to deny service to benign users or to otherwise disable a software system.

The techniques use an efficient guided symbolic execution of a program to compute bounds on the worst‐case complexity (for increasing input sizes) and to generate test values that trigger the worst‐case behaviours. The resulting bounds are fitted to a function to obtain a prediction of the worst‐case program behaviour at any input size. Scalability is achieved by using path policies that guide the symbolic execution towards worst‐case paths. The policies are learned from the worst‐case results obtained with exhaustive exploration at small input sizes and are applied to guide exploration at larger input sizes, where unguided exhaustive exploration is not possible. To achieve precision in the analysis, the path policies take into account the history of choices made along the path when deciding which branch to execute next. Furthermore, the computation is contextpreserving, meaning that the decision for each branch depends on the history computed with respect to the enclosing method.

We further report preliminary results on a complementary technique that uses machine learning for building the path policies that guide the search.

The techniques are implemented in open‐source projects that build on the Symbolic Pathfinder tool for analysing Java programs. Experimental evaluation shows that the techniques can find vulnerabilities in complex Java programs and can outperform previous symbolic approaches.
Performance analysis of recycled aggregate concrete with chemical admixture
Authors: Kannan Subbareddiar , Arunachalam Kalidass , Brindha Dharmar
Published: February 2020

Rapid growth in construction has resulted in usage of large quantity of natural resources leading to the degradation of environment. Also, the demolition waste is on the rise year by year due to ending of service of the building and modifications to meet latest requirements. Adoption of technology for recycling the construction and demolition (C and D) waste provides a better way of resolving this issue and it will lead to environmental sustainability. Recycled Concrete Aggregate (RCA) is one such environment‐friendly material. RCA usually possess greater porosity and lower density and strength when compared to natural aggregate. Most of the experiments proved that the reduction in the strength of recycled aggregate concrete (RAC) is not appreciable up to 40% replacement of natural aggregate with RCA. In the case of RAC, there will be two layers of interfacial transition zone (ITZ). ITZ due to old mortar adhered with aggregate will have greater porosity. Increase in the replacement of natural aggregate with RCA will increase the porosity in the given mass of concrete. This experimental investigation aims at improving the impermeability of RAC by adding chemical admixture which enhances the strength and durability performance.
Evaluation of a Ruthenium coordination complex as photosensitizer for PDT of bladder cancer: Cellular response, tissue selectivity and in vivo response
Authors: Lilge Lothar , Roufaiel Mark , Lazic Savo , Kaspler Pavel , Munegowda Manjunatha A. , Nitz Mark , Bassan Jay , Mandel Arkady
Published: February 2020

TLD1433, a Ru(II) polypyridyl complex, was recently introduced. It can be activated in the 520 to 540 nm range. Here we report on the use of TLD1433 for the treatment of bladder carcinomas in vitro and in an in vivo orthotopic model. The electrostatic properties of the normal urothelium vs a tumor compromised urothelium provide for a high selective uptake ratio. In vitro, a 1000 difference in the LD50 between dark and 22.5 J cm−2 irradiation at 530 nm was achieved for two bladder cell lines (T24 and AY‐27). In dogs and rats the plasma concentration for TLD1433 was below 100 ng kg−1 at 72 hours following intravenous injection at a dose of up to 3.5 mg kg−1 and below 10 ng kg−1 following intrabladder instillation for 1 hour at a concentration of 6 mg mL−1. Successful tumor necrosis close to 1.5 mm in depth was achieved.
Re‐envisioning stormwater infrastructure for ultrahazardous flooding
Authors: Sanders Brett F. , Grant Stanley B.
Published: February 2020

Ultrahazardous flooding (UHF) occurs on low relief topography at the foot of mountain catchments and is characterized by rapid‐onset, high‐velocity flood flows, large fluxes of sediment and debris, and unpredictable flow paths. 20th century stormwater infrastructure seeks to contain UHF, up to a design level, using combinations of basins, reservoirs and flood control channels. However, these flood control elements may increase the risk of disasters due to: (a) increasingly frequent and intense wildfires that amplify streamflow and debris fluxes beyond infrastructure design capacity; (b) aging and underfunded infrastructure which is susceptible to clogging and failure during extreme events; and (c) expansive urban development where communities are relatively unaware and underprepared for flooding as a consequence of the “levee effect”‐‐the false sense of safety that develops in the presence of flood defenses. 20th century stormwater infrastructure for UHF has also left communities with a legacy of social and environmental challenges including poor water quality, degraded habitats, high maintenance costs, unrealized urban amenities, and altered sediment fluxes. Adopting the Los Angeles Metropolitan Region as a type‐locality for UHF, we propose a new paradigm for stormwater infrastructure based on the concept of erodible flood corridors. Our vision aims for greater sustainability and resilience to extreme events based on congruency with natural processes, conservation of resources and associated ecosystem services, minimization of flood exposure and vulnerability, and avoidance of legacy risk and energy intensive practices.

This article is categorized under:

Engineering Water > Sustainable Engineering of Water

Engineering Water > Planning Water

Science of Water > Water Extremes
Post‐installation adaptation of offshore wind turbine controls
Authors: Smilden Emil , Sørum Stian H. , Bachynski Erin E. , Sørensen Asgeir J. , Amdahl Jørgen
Published: February 2020

The cost of offshore wind energy can be reduced by incorporating control strategies to reduce the support structures' load effects into the structural design process. While effective in reducing the cost of support structures, load‐reducing controls produce potentially costly side effects in other wind turbine components and subsystems. This paper proposes a methodology to mitigate these side effects at the wind farm level. The interaction between the foundation and the surrounding soil is a major source of uncertainty in estimating the safety margins of support structures. The safety margins are generally closely correlated with the modal properties (natural frequencies, damping ratios). This admits the possibility of using modal identification techniques to reassess the structural safety after installing and commissioning the wind farm. Since design standards require conservative design margins, the post‐installation safety assessment is likely to reveal better than expected structural safety performance. Thus, if load‐reducing controls have been adopted in the structural design process, it is likely permissible to reduce the use of these during actual operation. Here, the probabilistic outcome of such a two‐stage controls adaptation is analyzed. The analysis considers the structural design of a 10 MW monopile offshore wind turbine under uncertainty in the site‐specific soil conditions. Two control strategies are considered in separate analyses: (a) tower feedback control to increase the support structure's fatigue life and (b) peak shaving to increase the support structure's serviceability capacity. The results show that a post‐installation adaptation can reduce the farm‐level side‐effects of load‐reducing controls by up to an order of magnitude.
Modular invariant models of lepton masses at levels 4 and 5
Authors: Criado Juan Carlos , Feruglio Ferruccio , King Simon J. D.
Published: February 2020

Abstract

We explore alternative descriptions of the charged lepton sector in modular invariant models of lepton masses and mixing angles. In addition to the modulus, the symmetry breaking sector of our models includes ordinary flavons. Neutrino mass terms depend only on the modulus and are tailored to minimize the number of free parameters. The charged lepton Yukawa couplings rely upon the flavons alone. We build modular invariant models at levels 4 and 5, where neutrino masses are described both in terms of the Weinberg operator or through a type I seesaw mechanism. At level 4, our models reproduce the hierarchy among electron, muon and tau masses by letting the weights play the role of Froggatt-Nielsen charges. At level 5, our setup allows the treatment of left and right handed charged leptons on the same footing. We have optimized the free parameters of our models in order to match the experimental data, obtaining a good degree of compatibility and predictions for the absolute neutrino masses and the C P violating phases. At a more fundamental level, the whole lepton sector could be correctly described by the simultaneous presence of several moduli. Our examples are meant to make a first step in this direction.
Enlarging the scope of resonant di-Higgs searches: hunting for Higgs-to-Higgs cascades in 4b final states at the LHC and future colliders
Authors: Barducci D. , Mimasu K. , No J. M. , Vernieri C. , Zurita J.
Published: February 2020

Abstract

We extend the coverage of resonant di-Higgs searches in the b$$ \overline{b} $$

b
¯

b$$ \overline{b} $$

b
¯

final state to the process pp → H1→ H2H2→ b$$ \overline{b} $$

b
¯

b$$ \overline{b} $$

b
¯

, where both H1,2 are spin-0 states beyond the Standard Model. Such a process constitutes a joint discovery mode for the new states H1 and H2. We present the first sensitivity study of this channel, using public LHC data to validate our analysis. We also provide a first estimate of the sensitivity of the search for the HL-LHC and future facilities like the HE-LHC and FCC-hh. We analyze the discovery potential of this search for several non-minimal scalar sector scenarios: an extension of the SM with two extra singlet scalar fields, the two-Higgs-doublet model and a two-Higgs doublet model plus a singlet, which captures the scalar potential features of the NMSSM. We find that this channel represents a novel, very powerful probe for extended Higgs sectors, offering complementary sensitivity to existing analyses.
Therapie der Polyneuropathie – autonome Symptome und Schmerzen
Authors: Sachau J. , Fabig S.-C. , Rehm S. , Baron R.
Published: February 2020

Hintergrund

Die Therapie der Polyneuropathie beinhaltet die symptomatische Behandlung sensibler, motorischer und autonomer Funktionsstörungen.

Ziel

Der Beitrag soll einen Überblick über aktuelle Therapieempfehlungen bei Polyneuropathie geben. Der Fokus liegt dabei auf der Schmerztherapie.

Material und Methoden

Basierend auf einer Literaturrecherche werden die aktuellen Empfehlungen zur Therapie diskutiert.

Ergebnisse

Mittel der ersten Wahl zur Therapie von Schmerzen bei Polyneuropathie sind die an Kalziumkanälen ansetzenden Antikonvulsiva Gabapentin und Pregabalin sowie die Antidepressiva Amitriptylin und Duloxetin. Alternativ können bei lokalisierten Beschwerden topische Therapeutika eingesetzt werden. In Einzelfällen kann der Einsatz von Opioiden sowie anderen Antidepressiva und Antikonvulsiva erwogen werden. Limitiert wird die Therapie im Allgemeinen durch Nebenwirkungen vor allem zentralnervöser Art.

Schlussfolgerung

Generell sollte die Therapie multimodal erfolgen und die Behandlung weiterer Beschwerden umfassen. Bei der Auswahl der Schmerzmedikation sollten Komorbiditäten, Patientenalter und Nebenwirkungen berücksichtigt werden. Eine Stratifizierung der Patienten anhand des Phänotyps könnte dabei helfen, das bestmögliche Therapieansprechen zu erzielen.
Experimental investigation and optimisation of the micro milling process of hardened hot-work tool steel
Authors: Balázs B. Z. , Takács M.
Published: February 2020

In the past few decades, demand for precise miniature components has grown significantly. Modern production technologies required for the production of such components, including micro milling, have become extensively researched areas. In spite of the intensive research in this field, there are still many topics and aspects that merit investigation. Through a systematic series of experiments, this paper analyses the special characteristics of micro milling including cutting forces, vibrations, burr formation, and surface quality. A 5-axis micromachining centre with 60.000 rpm maximum spindle speed was used for the experiments carried out in the scope of this paper, and the machining of hardened hot-work tool steel (AISI H13) with a hardness of 50 HRC was investigated in detail. Also, a special measurement environment was prepared in order to collect machining data. Based on the results of the experiments, a power regression prediction model for cutting forces was created. As part of the analysis in the scope of the experiments, fast Fourier transformation was carried out in order to analyse the dynamic characteristics of the micro milling process, and to determine dominant frequencies. In addition, an analysis of variance (ANOVA) was applied to extensively analyse the main effects and interactions of different cutting parameters on different characteristics. Based on the investigations carried out in a comprehensive parameter range, an optimal parameter combination was also determined. The results of the experiments introduced in this paper contribute to a deeper understanding of the micro milling process, and this research provides information directly applicable in the industry.
The Economic Value of the Delivery of Primary Cleft Surgery in Timor Leste 2000–2017
Authors: Nandoskar Priya , Coghlan Patrick , Moore Mark H. , Ximenes Joao , Moore Eileen M. , Karnon Jonathan , Watters David A.
Published: February 2020

Background

Plastic and reconstructive surgical teams visiting from Australia, a high‐income country, have delivered cleft surgical services to Timor Leste since 2000 on a volunteer basis. This paper aims to estimate the economic benefit of correcting cleft deformities in this new nation as it evolved its healthcare delivery service from independence in 1999.

Methods

We have utilised a prospective database of all cleft surgical interventions performed during 44 plastic surgical missions over the last 18 years. The disability‐adjusted life year (DALY) framework was used to calculate the total DALYs averted by primary cleft lip and palate repair. The 2004 global burden of disease disability weights were used. Economic benefits were calculated using the gross national income (GNI) and the value of a statistical life (VSL) methods for Timor Leste. Estimates were adjusted for treatment effectiveness, counterfactual cases, and complications. Cost estimates included the local hospitalisation costs, the foregone salaries of the visiting surgeons and nurses, other costs associated with providing surgical care, and an estimate for foregone wages of the patients or their carers. Sensitivity analysis was performed with income elasticity set to 0.55, 1.0, and 1.5.

Results

During 44 visiting plastic surgical missions to Timor Leste, 1500 procedures were performed, including 843 primary cleft lip and palate operations. The cleft procedures resulted in the aversion of 842 DALYs and an economic return to Timor Leste of USD 2.2 million (GNI‐based) or USD 197,917 (VSL‐based). Our programme cost USD 705 per DALY averted. The economic return on investment was 0.3:1 (VSL‐based) or 3.8:1 (GNI‐based).

Conclusion

A sustained and consistent visiting team approach providing repair of cleft lip and palate defects has resulted in considerable economic gain for Timor Leste over an 18‐year period. The training of a local surgeon and multidisciplinary team with ongoing support to the in‐country cleft service is expected to reduce the cost per DALY averted once the surgeon and team are able to manage clefts independently.
Impact of Hepatic Artery Variations and Reconstructions on the Outcome of Orthotopic Liver Transplantation
Authors: Karakoyun Rojbin , Romano Antonio , Yao Ming , Dlugosz Rafal , Ericzon Bo‐Göran , Nowak Greg
Published: February 2020

Background

Donor variational arteries often require complex reconstruction.

Methods

We analysed the incidence of different variations, types of arterial reconstructions and their impact on post‐operative results from 409 patients undergoing liver transplantation at Karolinska Institute between 2007 and 2015.

Results

A total of 292 (71.4%) liver grafts had a standard hepatic artery (SHA), and 117 (28.6%) showed hepatic artery variants (HAV). 58% of HAV needed reconstruction. The main variations were variant left hepatic artery (45.3%) from the gastric artery; variant right hepatic artery (38.5%); and a triple combination of variant right and left hepatic artery and the proper hepatic artery from the common hepatic artery (12.8%); other 3.4%. Patients/graft survival and arterial complications were not different between SHA and HAV. Incidence of biliary stricture was numerically higher in left hepatic artery variants (p = 0.058) and in variants where no arterial reconstruction was performed (p = 0.001). Operation and arterial warm ischaemia time were longer in the HAV group. The need for intraoperative re‐reconstruction was higher in the HAV group (p = 0.04). Intraoperative bleeding was larger after back‐table reconstruction than with intraoperative reconstruction (p = 0.04).

Conclusion

No overall differences were found between the HAV and the SHA groups. Occurrence of a variant left hepatic artery and HAV with no reconstruction seems to increase the risk of biliary strictures.
Barriers to Surgical Care Among Children in Somaliland: An Application of the Three Delays Framework
Authors: Concepcion Tessa L. , Dahir Shukri , Mohamed Mubarak , Hiltbrunn Kyle , Ismail Edna Adan , Poenaru Dan , Rice Henry E. , Smith Emily R. ,   the Global Initiative for Children's Surgery
Published: February 2020

Background

There are complex barriers that increase delays to surgical care in low‐ and middle‐income countries, particularly among the vulnerable population of children. Understanding these barriers to surgical care can result in targeted and strategic intervention efforts to improve care for children. The three‐delay model is a widely used framework in global health for evaluating barriers associated with seeking (D1), reaching (D2), and receiving health care (D3). The goal of our study is to evaluate reasons for delays in the surgical care for children in Somaliland using the three‐delay framework.

Methods

Data were collected in a cross‐sectional study in Somaliland from 1503 children through a household survey. Among children with a surgical need, we quantified the number of children seeking, reaching, and receiving care along the surgical care continuum, according to the three‐delay framework. We evaluated predictors of the three delays through a multivariate logistic regression model, including the child's age, gender, village type, household income level, region, and household size.

Results

Of the 196 children identified with a surgical condition, 50 (27.3%) children had a delay in seeking care (D1), 28 (20.6%) children had a delay in reaching care (D2), and 84 (71.2%) children had a delay in receiving care (D3), including 10 children who also experienced D1 and D2. The main reasons cited for D1 included seeking a traditional healthcare provider, while lack of money and availability of care were main reasons cited for D2. Significant predictors for delays included household size for D1 and D3 and condition type and region for D2.

Conclusion

Children in Somaliland experience several barriers to surgical care along the entire continuum of care, allowing for policy guidance tailored to specific local challenges and resources. Since delays in surgical care for children can substantially impact the effectiveness of surgical interventions, viewing delays in surgical care under the lens of the three‐delay framework can inform strategic interventions along the pediatric surgical care continuum, thereby reducing delays and improving the quality of surgical care for children.
The p48 Flow Modulation Device with Hydrophilic Polymer Coating (HPC) for the Treatment of Acutely Ruptured Aneurysms: Early Clinical Experience Using Single Antiplatelet Therapy
Authors: Aguilar-Perez Marta , Hellstern Victoria , AlMatter Muhammad , Wendl Christina , Bäzner Hansjörg , Ganslandt Oliver , Henkes Hans
Published: February 2020

Background

Flow diversion (FD) remains a potential treatment option following aneurysmal subarachnoid hemorrhage (aSAH) when standard options may not be feasible. However, it should not be considered a first-line treatment due to the need for dual antiplatelet therapy (DAPT). The hydrophilic polymer coating on the p48MW flow diverter (HPC, phenox) is a surface modification that inhibits platelet adhesion. This study aims to report on our early single-center experience using the p48MW HPC (phenox) flow diverter with single antiplatelet therapy (SAPT) following an aSAH.

Materials and Methods

We retrospectively identified all patients who had been treated with the p48MW HPC for aSAH under SAPT. All patients treated within 30 days following an aSAH were included. Any occurrence of thromboembolic and hemorrhagic complications was recorded alongside angiographic and clinical follow-up details.

Results

Eight patients were identified. The mean interval between aSAH and FD was 6 days. Of the eight ruptured aneurysms, one was blister-like, one saccular, one mycotic, and the remaining five were dissecting aneurysms. Intraprocedural transient thrombus formation was observed in four patients (50%). Stent thrombosis was observed in one patient (12.5%) on day 3 with spontaneous recanalization after being switched onto DAPT. None of the aneurysms rebled after treatment. Two patients died due to cerebral vasospasm. Complete aneurysm occlusion had been achieved in all but one patient at angiographic follow-up (average 6 months).

Conclusions

This small series highlights the possibility and limitations of using the p48MW HPC with SAPT in ruptured aneurysms. Randomized trials with longer follow-up in larger cohorts are underway.
Genetic structure of Doronicum austriacum (Asteraceae) in the Carpathians and adjacent areas: toward a comparative phylogeographical analysis of tall-herb species
Authors: Stachurska-Swakoń Alina , Cieślak Elżbieta , Ronikier Michał , Nowak Justyna , Kaczmarczyk Agnieszka
Published: February 2020

Tall-herb communities play an important role in the vegetation of the European mountains. They are developed in humid habitats with nutrient-rich soil, from submontane to subalpine zones. As its contemporary flora consists of different geographical elements, their history, especially in relation to the climatic oscillations throughout the Pleistocene, is not straightforward. We analyze the phylogeography of Doronicum austriacum, one of the main species building Central European tall-herb communities. We additionally discuss these new data in the context of earlier phylogeographical studies of key species of tall-herb communities to compare the major patterns of their lineage distributions. The study was based on AFLP fingerprinting and DNA sequencing of sampled populations from the Carpathians and adjacent lowland, Alps, Sudetes, and Balkan Peninsula. Our results confirm the phylogeographical break between the Western and South-Eastern Carpathians as a major regional biogeographical feature. Close affinity of the Western Carpathian and Sudetes populations was also confirmed as a significant feature in common for studied tall-herb species. In contrast to the phylogeographical structure of other tall-herb species, a divergence of D. austriacum populations from the Balkan Peninsula was observed supporting the presence of divergent and taxonomically distinct lineage in the latter area. The general phylogeographical pattern indicates past survival in several distinct areas but only partly common features for the community level emerge. Finally, the history of low-elevation populations of D. austriacum at the northern margin of the distribution range remains unclear but mainly their close affinity to the forest Western Carpathian populations is suggested.
Biofunctionalization of porcine-derived collagen matrices with platelet rich fibrin: influence on angiogenesis in vitro and in vivo
Authors: Blatt Sebastian , Burkhardt Valentin , Kämmerer Peer W. , Pabst Andreas M. , Sagheb Keyvan , Heller Martin , Al-Nawas Bilal , Schiegnitz Eik
Published: February 2020

Objectives

Porcine-derived collagen matrices (CM) can be used for oral tissue regeneration, but sufficient revascularization is crucial. The aim of this study was to analyze the influence of platelet-rich fibrin (PRF) on angiogenesis of different CM in vitro and in vivo.

Materials and methods

Three different CM (mucoderm, jason, collprotect) were combined with PRF in a plotting process. Growth factor release (VEGF, TGF-β) was measured in vitro via ELISA quantification after 1,4 and 7 days in comparison to PRF alone. In ovo yolk sac (YSM) and chorion allantois membrane (CAM) model, angiogenic potential were analyzed in vivo with light- and intravital fluorescence microscopy after 24 h, then verified with immunohistochemical staining for CD105 and αSMA.

Results

Highest growth factor release was seen after 24 h for all three activated membranes in comparison to the native CM (VEGF 24 h: each p < 0.05; TGF-β: each p < 0.001) and the PRF (no significant difference). All activated membranes revealed a significantly increased angiogenic potential in vivo after 24 h (vessels per mm2: each p < 0.05; branching points per mm2: each p < 0.01; vessel density: each p < 0.05) and with immunohistochemical staining for CD105 (each p < 0.01) and αSMA (each p < 0.05).

Conclusions

PRF improved the angiogenesis of CM in vitro and in vivo.

Clinical relevance

Bio-functionalization of CM with PRF could easily implemented in the clinical pathway and may lead to advanced soft tissue healing.
Disease activity, morning stiffness and missing teeth are associated with oral health-related quality of life in individuals with rheumatoid arthritis
Authors: Schmalz Gerhard , Noack Stefan , Patschan Susann , Patschan Daniel , Müller Gerhard A. , Rupprecht Annegret , Schmickler Jan , Haak Rainer , Ziebolz Dirk
Published: February 2020

Objectives

The aim of this cross-sectional study was to assess oral health-related quality of life (OHRQoL) in patients with rheumatoid arthritis (RA) and its relation to specific RA characteristics.

Material and methods

Within the oral examination, the need for dental (carious teeth showing cavitation) and periodontal treatment (presence of a probing depth ≥ 3.5 mm) and the number of missing teeth (M-T) were recorded. OHRQoL was assessed with the German short version of the Oral Health Impact Profile (OHIP G14). The disease activity score (DAS28-ESR), disease duration, number of swollen/painful joints and duration of morning stiffness were retrieved from the patient records.

Results

A total of 176 patients with a mean age of 62.5 ± 10.2 years were included. The overall OHIP G14 sum score was 5.4 ± 7.1. The M-T showed a significant correlation with the dimensions of oral function (r = 0.25, p = 0.001) and psychosocial impact (r = 0.20, p = 0.009) and the sum score (r = 0.26, p = 0.001). The DAS28-ESR showed a significant correlation with psychosocial impact (r = 0.19, p = 0.012) and the sum score (r = 0.16, p = 0.041). The duration of morning stiffness was correlated with oral function (r = 0.19, p = 0.019), psychosocial impact (r = 0.18, p = 0.024) and the sum score (r = 0.22, p = 0.006). The effect size of these correlations was interpreted as small.

Conclusion

Disease activity, morning stiffness and missing teeth are associated to OHRQoL of patients with RA. Accordingly, multidisciplinary dental care appears necessary for these patients.

Clinical relevance

The prevention of tooth loss as well as the consideration of psychosocial and disease-specific parameters in the multidisciplinary dental care of RA patients is necessary.
Experimentelle Ermittlung der Ölströmung in tauchgeschmierten Schneckengetrieben
Authors: Norgauer Philipp , Grunewald Laura , Priester Lena , Heilemann Jens , Hein Michael , Stahl Karsten
Published: February 2020

Schneckengetriebe finden sich in verschiedenen Anwendungen als Stell- und Leistungsgetriebe. Aufgrund der Realisierbarkeit einer hohen Übersetzung bei kleinem Bauraum ermöglichen sie effiziente und kompakte Antriebskonzepte, auch bei sicherheitskritischen Anwendungen, da sie selbsthemmend ausgeführt werden können.

Im Betrieb von Getrieben ergeben sich Verluste, welche zum einen in der Verzahnung, zum anderen durch andere Maschinenelemente wie Lager- oder Dichtungen entstehen. Diese Verluste werden größtenteils in Form von Wärme an das Getriebeöl abgegeben, welches sie wiederum an das Gehäuse abgibt. Im Betrieb wird das Öl im Gehäuseinneren in Bewegung versetzt, sodass ein Wärmetransport in Form von Konvektion erfolgt. Es entstehen komplexe Strömungen im Gehäuseinneren. Die Ausprägung dieser Strömungen bestimmt maßgeblich den thermischen Betriebspunkt und hat damit auch Einfluss auf Wirkungsgrad und Tragfähigkeit des Getriebes.

In diesem Artikel werden die Ergebnisse von Untersuchungen zur Ölsumpfströmung vorgestellt. Hierfür wurde das Gehäuse eines Serienschneckengetriebes mit durchsichtigen Deckeln adaptiert, sodass die im Betrieb des Getriebes auftretende Ölströmung erfasst werden konnte. Über verschiedene Versuchspunkte wurden die entstehenden Strömungen dokumentiert. Anschließend wurden die Versuchsdaten mit Strömungsmodellen der Literatur abgeglichen, sodass mit dieser Veröffentlichung erste Beschreibungsansätze für die im Betrieb vorliegende Ölströmung in tauchgeschmierten Schneckengetrieben vorgestellt werden.
The beneficial effect of cold atmospheric plasma on parameters of molecules and cell function involved in wound healing in human osteoblast-like cells in vitro
Authors: Eggers B. , Marciniak J. , Memmert S. , Kramer F. J. , Deschner J. , Nokhbehsaim M.
Published: February 2020

The aim of this study was to analyse the effect of cold atmospheric plasma (CAP) on human osteoblast-like cells in vitro. Additionally, underlying intracellular mechanisms were to be studied. Human osteoblast-like (MG63) cells were exposed to CAP for 60 s. The effects of CAP on key molecules essential for the wound healing response were studied using real-time PCR, ELISA and immunocytochemistry. For studying intracellular signalling pathways, MAP kinase MEK 1/2 was blocked. Cell viability was analysed by an XTT assay and with an EVE automated cell counter. Cell migration was examined by an in vitro wound healing assay.

CAP exposition on osteoblast-like cells caused a significant upregulation of interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor (TNF)α, cyclooxygenase (COX)2, collagen (COL) 1α, matrix metalloproteinase (MMP)1, Ki67, proliferating-cell-nuclear-antigen (PCNA) and chemokine ligand (CCL)2 mRNA expression at 1 day. Interestingly, after blocking of MAP kinase, CAP-induced upregulation of Ki67 was inhibited by 57%. Moreover, CAP treatment improved significantly osteoblast-like cell viability as compared to untreated cells at 1 day. Beneficial effect of CAP treatment was shown by an in vitro wound healing assay, displaying a significant faster wound closure. Our findings provide evidence that CAP exposure effects gene and protein regulation in human osteoblast-like cells. Furthermore, CAP treatment has a positive impact on wound closure in an in vitro setting and might improve existing concepts of hard tissue regeneration in the future.
Corporate social responsibility vs. financial interests: the case of responsible gambling programs
Authors: Fiedler Ingo , Kairouz Sylvia , Reynolds Jennifer
Published: February 2020

Aim

Corporate social responsibility (CSR) is supposed to play an important part in public health. Critics argue that opposing financial interests can prevent companies from implementing effective CSR programs. We shed light on this discussion by analyzing CSR programs of gambling operators.

Subjects and methods

Two data sets are used: (1) seven responsible gambling (RG) programs of German slot machine hall operators and (2) a survey carried out among 512 problem gamblers in treatment who play primarily in slot machines halls.

Results

Results show that the RG programs list mostly mandatory measures with one major exception: to approach possible problem gamblers with the intention to help them. However, operators’ staff approach only 1% of problem gamblers.

Conclusion

We argue that the observed ineffective implementation of voluntary CSR measures is grounded in the strong financial incentive of operators to serve precisely the group they should stop from playing: problem gamblers. We conclude that financial interests reduce the effectiveness of CSR.
Identity Drift: The Multivocality of Ethical Identity in Islamic Financial Institution
Authors: Hidayah Nunung Nurul , Lowe Alan , De Loo Ivo
Published: February 2020

In today’s neo-liberalist world, Islamic financial institutions (IFIs) face many difficulties combining contemporary financial thinking with Islamic, faith-based principles, on which their day-to-day operations ought to be based. Hence, IFI are likely to experience shifts/changes in organizational and ethical identity due to tensions that the combination of these principles invokes. We present an in-depth case study that focuses on these shifts in a major European based IFI across a 14-year period. We conceptualize identity change as drift, highlighting the multivocal nature of identity construction. The ethico-faith principles that were meant to serve as living codes of ethics guiding the IFI’s organizational culture, operational processes, and strategy formation turned out to mainly have been discursively rationalized to respond to regulatory, market and institutional imperatives. The company is aware that it needs to engage in a continuous dialogue with those who set these requirements. Its ethico-faith principles may consequently be adapted quite radically, especially in periods of turmoil and takeover, as we show across the analysed time period. The paper provides valuable insights for faith-inspired organizations to reflect on the extent to which they wish to engage in the discursive justification and legitimization of current market hegemonies, whilst they actively encourage their managers to behave ethically as well.
Identifying Suitable Bioeconomic Cluster Sites—Combining GIS-MCDA and Operational Research Methods
Authors: Nørstebø Vibeke , Krøgli Svein Olav , Debella-Gilo Misganu , Perez-Valdes Gerardo A. , Uggen Kristin T. , Dramstad Wenche E.
Published: February 2020

A transition to a bioeconomy implies an increased focus on efficient and sustainable use of biological resources. A common, but often neglected feature of these resources is their location dependence. To optimize their use, for example in bioeconomic industrial clusters, this spatial aspect should be integrated in analyses. Optimal design and localization of a bioeconomic cluster with respect to the various biological and non-biological resources required for the cluster, the composition of industrial facilities in the cluster, as well as the demands of the outputs of the cluster, is crucial for profitability and sustainability. We suggest that optimal design and location of bioeconomic clusters can benefit from the use of a Multicriteria Decision Analysis (MCDA) in combination with Geographic Information Systems (GIS) and Operations Research modeling. The integration of MCDA and GIS determines a set of candidate locations based on various criteria, including resource availability, accessibility, and usability. A quantitative analysis of the flow of resources between and within the different industries is then conducted based on economic Input-Output analysis. Then, the cluster locations with the highest potential profit, and their composition of industrial facilities, are identified in an optimization model. A case study on forest-based bioeconomic clusters in the Østfold county of Norway is presented to exemplify this methodology, the expectation being that further implementation of the method at the national level could help decision makers in the planning of a smoother transition from a fossil-based economy to a bioeconomy.
Exergy and energy amelioration for parabolic trough collector using mono and hybrid nanofluids
Authors: Al-Oran Otabeh , Lezsovits Ferenc , Aljawabrah Ayham
Published: February 2020

Energy and exergy efficiency amelioration of the parabolic trough has taken high interest since recent years, especially when nanofluid used as an enhancement category. This paper aimed to improve LS-2 parabolic trough model and compare the enhancement effect that occurred using different mono and hybrid nanofluids. Inserting mono nanoparticles of Al2O3, CeO2, CuO, and hybrid combinations of Al2O3 with CeO2, or CuO nanoparticles in a Syltherm 800 was investigated by five different cases. The investigation was presented under total volume fraction 4% for all nanofluids and mixing fraction 50:50 for the hybrid types in order to facilitate the analysis and compare various results at the same conditions. Those cases and their comparisons were solved using MATLAB Symbolic tools under turbulent flow regime and variable inlet temperature to present wide domain behavior for the energy and exergy efficiency, Nusselt number, heat transfer coefficient, and pressure drop, whereas the analytical solution of the energy balance equation was taken from the literature and improved to cover the mentioned cases. Moreover, the results were compared with previous researches that used different thermal fluid and showed high accuracy behavior with low deviation. Therefore, the findings showed that Al2O3 and CeO2 hybrid nanofluids were more efficient than using of both Al2O3 and CuO hybrid nanofluids and any mono nanofluids contain the same nanoparticles. The maximum enhancement of thermal and exergy efficiency of using Al2O3 and CeO2 hybrid nanofluids was 1.09% and 1.03%, respectively, whereas it was enhanced by 167.8% and 200.7% for the Nusselt number and heat transfer coefficient, respectively. Also, the hybrid nanofluids have higher advantage over the mono nanofluids by presenting lower pressure drop values. Finally, the assessment of efficiency variation affected by thermal properties of the nanoparticle was presented under optimum temperature equal to 575 K.
Network Risk Assessment Based on Baum Welch Algorithm and HMM
Authors: Wang Chundong , Li Kongbo , He Xiaonan
Published: February 2020

With the increasingly extensive applications of the network, the security of internal network of enterprises is facing more and more threats from the outside world, which implies the importance to master the network risk assessment skills. To improve the accuracy is an importent issue. In the big data era, there are various security protection techniques and different types of group data. Meanwhile, Online Social Networks (OSNs) and Social Internet of Things (SIoT) are becoming popular patterns of meeting people and keeping in touch with friends (Jiang et al. ACM Comput Surv 49:10:1–10:35 2016; Shen et al. 2017). Risk assessment, as a bridge between security experts and network administrators, whose accuracy can influence the judgment of administrators to the entire network state. In order to solve this problem, this essay uses the Baum Welch algorithm to optimize the risk assessment process by establishing the HMM model, which can improve the accuracy of the evaluation value. Firstly, behavior of the attacker is described in-depth by the attack graph generated through MulVAL framework. Then, the nodes on the attack path can will be evaluated and the value will be further evaluated by the Bayesian model. Finally, by establishing the hidden Markov model, the corresponding parameters can be defined and the most likely probabilistic state transition sequence can be calculated by using the Viterbi algorithm and Baum Welch algorithm to deduce the attack intent with the highest possibility.
The occupational trajectories and outcomes of forced migrants in Sweden. Entrepreneurship, employment or persistent inactivity?
Authors: Backman Mikaela , Lopez Esteban , Rowe Francisco
Published: February 2020

The current surge in forced migration to Europe is probably the largest and most complex since the Second World War. As population aging accelerates and fertility falls below replacement level, immigration may be seen as a key component of human capital to address labor and skill shortages. Receiving countries are, however, hesitant about the contribution that forced migrants can make to the local economy. Coupled with increasing pressure on welfare services, they are associated with increased job competition and crime. Underutilization of immigrants’ skills is, however, a waste of resources that countries can scarcely afford. Understanding the labor market integration process of forced migrants is thus critical to develop policies that unleash their full skills potential and ultimately foster local economic productivity. While prior studies have examined the employment and salary outcomes of these immigrants at a particular point in time post-migration, they have failed to capture the temporal dynamics and complexity of this process. Drawing on administrative data from Sweden, we examine the occupational pathways of forced migrants using sequence analysis from their arrival in 1991 through to 2013. Findings reveal polarized pathways of long-term labor market integration with over one-third of refugees experiencing a successful labor market integration pathway and an equally large share facing a less fruitful employment outcomes. Our findings suggest education provision is key to promote a more successful integration into the local labor market by reducing barriers of cultural proximity and increasing the occurrence of entrepreneurship activity.
ChIP-seq and RNA-seq for complex and low-abundance tree buds reveal chromatin and expression co-dynamics during sweet cherry bud dormancy
Authors: Vimont Noémie , Quah Fu Xiang , Schöepfer David Guillaume , Roudier François , Dirlewanger Elisabeth , Wigge Philip A. , Wenden Bénédicte , Cortijo Sandra
Published: February 2020

Chromatin immunoprecipitation-sequencing (ChIP-seq) is a robust technique to study interactions between proteins, such as histones or transcription factors and DNA. This technique in combination with RNA-sequencing (RNA-seq) is a powerful tool to better understand biological processes in eukaryotes. We developed a combined ChIP-seq and RNA-seq protocol for tree buds (Prunus avium L., Prunus persica L Batch, Malus x domestica Borkh.) that has also been successfully tested on Arabidopsis thaliana and Saccharomyces cerevisiae. Tree buds contain phenolic compounds that negatively interfere with ChIP and RNA extraction. In addition to solving this problem, our protocol is optimised to work on small amounts of material. Furthermore, one of the advantages of this protocol is that samples for ChIP-seq are cross-linked after flash freezing, making it possible to work on trees growing in the field and to perform ChIP-seq and RNA-seq on the same starting material. Focusing on dormant buds in sweet cherry, we explored the link between expression level and H3K4me3 enrichment for all genes, including a strong correlation between H3K4me3 enrichment at the DORMANCY-ASSOCIATED MADS-BOX 5 (PavDAM5) loci and its expression pattern. This protocol will allow analysis of chromatin and transcriptomic dynamics in tree buds, notably during its development and response to the environment.
Microplastics in seawater: sampling strategies, laboratory methodologies, and identification techniques applied to port environment
Authors: Cutroneo Laura , Reboa Anna , Besio Giovanni , Borgogno Franco , Canesi Laura , Canuto Susanna , Dara Manuela , Enrile Francesco , Forioso Iskender , Greco Giuseppe , Lenoble Véronique , Malatesta Arianna , Mounier Stéphane , Petrillo Mario , Rovetta Ruben , Stocchino Alessandro , Tesan Javier , Vagge Greta , Capello Marco
Published: February 2020

The European Interreg Italy–France 2014–2020 Maritime Project SPlasH! (Stop to Plastics in H2O!) focused on the study of microplastics (MPs) in the marine port environment to evaluate their presence, abundance, and mechanisms of diffusion to the open sea. In the framework of this project, a worldwide review of 74 studies was carried out, providing an overview of MP investigation techniques, focusing on sampling strategies, laboratory methodologies, and identification of MPs collected in seawater, and specifically evaluating their applicability to the marine port environment. Nets were the most commonly used device for MP surface sampling, but their use can be difficult in narrow spaces within the port basins, and they must be coupled to discrete sampling devices to cover all port basins. In the laboratory, density separation (NaCl, ZnCl2, NaI, sodium lauryl sulfate (SLS)), filtration (polycarbonate, polyamide, glass, cellulose, ANOPORE inorganic membrane filters), sieving, visual sorting, and digestion methods (acidic, enzymatic, alkaline, oxidative) were used to separate MPs from seawater. Digestion becomes essential with water samples with great inorganic and organic loads as deriving from a port. Although many studies are based only on visual MP identification under a microscope, analytical identification techniques unequivocally determine the particle nature and the identity of the plastic polymers and are necessary to validate the visual sorting of MPs. Fourier-transform infrared spectroscopy (FTIR) is the most used analytical identification technique.
Etiology of Lumbosacral Radiculoplexopathy: Sacral Insufficiency Fracture on Magnetic Resonance Imaging
Authors: Geannette Christian , Lee Susan C. , Sneag Darryl B.
Published: February 2020

Background

Sacral insufficiency fracture (SIF) can cause lumbosacral radiculoplexopathy (LSRP) and is probably under-recognized. Symptoms may include nonspecific lumbar spine or buttock pain that is exacerbated by physical activity and alleviated with rest. The frequency of LSRP secondary to SIF has not been reported.

Questions/Purposes

We aimed to determine the frequency of LSRP associated with SIF using magnetic resonance imaging (MRI) of the lumbar spine.

Methods

We searched a radiology database at our institution using the keywords “sacral insufficiency fracture” and “lumbar spine MRI” for patient records from January 2014 through December 2017. We assessed for the presence of LSRP, reflected by elevated T2-weighted or short tau inversion recovery (STIR) signal intensity and enlargement of the nerve on noncontrast lumbar spine MRI. An incompletely healed vertically oriented SIF was confirmed if there was a persistent bone marrow edema pattern adjacent to the fracture site; we did not include purely transverse SIFs. The final cohort comprised 57 patients (48 female; age range, 14 to 89 years).

Results

Abnormalities of the extraforaminal L5 nerve root or the combined L4 and L5 nerve roots (the lumbosacral trunk) were identified in 19 (33%) of 57 patients, with a total of 23 sites (bilateral involvement in four cases). Of the 23 abnormal nerves, 19 (82.6%) had corresponding, clinically documented radicular symptoms and 16 (69.6%) had no other explanation on MRI for their radicular symptoms other than SIF.

Conclusions

LSRP caused by SIF is an entity all radiologists should be cognizant of, especially in cases of otherwise unexplained radicular symptoms. The diagnosis of SIF can be helpful in cases involving concomitant multilevel lumbar spondylosis and neural foraminal stenosis.