bluuebunny/crossref_metadata_2025 huggingface dataset:
Retracted: Synthesis, Molecular Properties, and Biological Evaluation of Hybrid 1,2,3‐Triazolylpolyaza Heterocyclic Compounds
Authors: Dasari Srinivasa Rao , Tondepu Subbaiah , Vadali Lakshmana Rao , Ganivada Mutyala Naidu , Seelam Nareshvarma
Published: December 2018

In this research article, a highly efficient, cost‐effective synthesis of various hybrid molecules possessing 1,2,3‐triazolyltetrazoles and evaluation of their biological activity have been addressed. The structure elucidation of these new library hybrid molecules has been carried out by IR, 1H NMR, 13C NMR, and mass spectral analysis. The compounds have been screened for their anticancer activity against human colon cancer cell line Colo‐205 and human lung cancer cell line HOP‐205, and the results attest that most of the compounds have shown very good therapeutic nature. In particular, compounds 3d, 3j, 6a, and 6e were more cytotoxic than Adriamycin against all tested human cancer cell lines with 68%, 101.8%, 94%, and 104.5% growth, respectively. In the present investigation, a series of 3a–j and 6a–h were subjected to molecular properties prediction, drug likeness by Molinspiration, and toxicity risks by Molsoft software programs. All the 18 analogues were chosen on the basis of Lipinski “Rule of five” for the synthesis, screening their antibacterial and anticancer as oral bioavailable drugs/leads.
Morphological variation and covariation in mandibular molars of platyrrhine primates
Authors: Delgado Mónica Nova , Pérez‐Pérez Alejandro , Galbany Jordi
Published: December 2018

Molars are highly integrated biological structures that have been used for inferring evolutionary relationships among taxa. However, parallel and convergent morphological traits can be affected by developmental and functional constraints. Here, we analyze molar shapes of platyrrhines in order to explore if platyrrhine molar diversity reflects homogeneous patterns of molar variation and covariation. We digitized 30 landmarks on mandibular first and second molars of 418 extant and 11 fossil platyrrhine specimens to determine the degree of integration of both molars when treated as a single module. We combined morphological and phylogenetic data to investigate the phylogenetic signal and to visualize the history of molar shape changes. All platyrrhine taxa show a common shape pattern suggesting that a relatively low degree of phenotypic variation is caused by convergent evolution, although molar shape carries significant phylogenetic signal. Atelidae and Pitheciidae show high levels of integration with low variation between the two molars, whereas the Cebinae/Saimiriinae, and especially Callitrichinae, show greater variation between molars and trend toward a modular organization. We hypothesize that biomechanical constraints of the masticatory apparatus, and the dietary profile of each taxon are the main factors that determine high covariation in molars. In contrast, low molar shape covariation may result from the fact that each molar exhibits a distinct ecological signal, as molars can be exposed to distinct occlusal loadings during food processing, suggesting that different selective pressures on molars can reduce overall molar integration.
Morphology and evolution of the wing bullae in South American Leptophlebiidae (Ephemeroptera)
Authors: Dominguez Eduardo , Abdala Virginia
Published: December 2018

Insects were the first animals to take to the skies, and have been flying for over 320 million years. The order Ephemeroptera is, or at least is part of, the most early‐diverging lineage of extant winged insects. The extant species present a very short adult life span, mainly dedicated to reproduction and dispersal of eggs. Mating and egg‐laying behavior depend on flight. Wings are structures to fly and as such face a number of physical and physiological challenges. The convex curvature along the anterior–posterior axis of the wing generates a camber that must be carefully regulated. One of the most interesting ways of wing bending is provided by the bullae, which have been defined as short sections of flexible chitin, where the flexion lines cross veins. Although the bullae have been frequently used as taxonomic characters, there is no study focused on their morphology, although their prevalence on the wings of mayflies strongly suggests a role in flight. In order to identify evolutionary trends of these structures within Ephemeroptera, we constructed a matrix with comparative anatomy data of the bullae from whole mounts of the wings of 300 specimens belonging to 70 species of several mayfly families, as well as scanning microscopy samples of selected specimens. We also surveyed the number of bullae and their distribution in the wings of the different species within the South American Leptophlebiidae clade. We optimized the characters onto the latest published phylogeny for Leptophlebiidae.
Drilling in the dorid species Vayssierea cf. elegans (Gastropoda: Nudibranchia): Functional and comparative morphological aspects
Authors: Mikhlina Anna L. , Tzetlin Alexander B. , Ekimova Irina A. , Vortsepneva Elena V.
Published: December 2018

The drilling mode of feeding is known from two clades of Gastropoda: Caenogastropoda and Heterobranchia. However, the level of convergence and parallelism or homology among these two lineages is unclear. The morphology of the buccal complex is well studied for drilling caenogastropods, but poorly known for drilling nudibranchs. It is also unclear whether the drilling feeding mechanism is similar between inside gastropods. Accordingly, a comparison between the feeding mechanisms of drilling nudibranchs and caenogastropods can help to understand the evolutional trends inside gastropods. In this study, we redescribe the morphology of the buccal complex of drilling dorid nudibranch Vayssierea cf. elegans, and compare it to that of previous investigations on this species and closely related dorid species. We describe the feeding mechanism of this species based on the obtained morphological and literature data and compare it to the feeding mechanisms described for drilling caenogastropods. The feeding apparatus of Vayssierea cf. elegans corresponds to the general morphology of the dorid buccal complex; that is, it has a similar arrangement of the buccal musculature and pattern of radular morphology. However, there are also adaptations to the drilling feeding mode similar to those found in Caenogastropoda: that is, specialized dissolving glands and lateral teeth with elongated pointed cusps; and even Sacoglossa: the specialized muscle for sucking. The feeding process of Vayssierea cf. elegans includes the same two stages as those described for drilling caenogastropods: (a) the boring stage, which is provided by mechanical and chemical activity, and (b) the swallowing stage.
Environmental filtering drives bacterial community structure and function in a subalpine area of northern China
Authors: Zhao Pengyu , Liu Jinxian , Jia Tong , Wang Yinggang , Chai Baofeng
Published: December 2018

Microbial community assembly is affected by the trade‐off between deterministic and stochastic processes, but the mechanisms underpinning their relative influences remain elusive. This knowledge gap strongly limits our ability to predict the effect of environmental filtering on microbial community structure and function. To improve the understanding of mechanisms underlying community assembly processes, we investigated bacterial community structure and function on a subalpine shady slope and a sunny slope in the Pangquangou National Nature Reserve in North China. By integrating the results of a null model and the RC metric, we inferred that a deterministic process, that is, environmental filtering, drove bacterial community biogeographical patterns. Edaphic factors caused the largest contribution to microbial community structure, followed by vegetation and spatial variables. Among edaphic factors, total carbon (TC) and total nitrogen (TN) were the most important factors as determined by redundancy analysis (RDA). Moreover, network analysis suggested that the status of bacterial community co‐occurrence was significantly greater than that of exclusive relationships. Under environmental stress, there was no significant difference in the overall bacterial community structure on the different slopes, while significant differences were observed in relation to community functions. Given this, we inferred that the degrees of response of bacterial community structure and function to varying environments were not consistent. In conclusion, our results contribute to the understanding of deterministic versus stochastic balance in bacterial community assembly and the response mechanisms of community structure and function to environmental heterogeneity.
Regenerative rehabilitation: The role of mechanotransduction in orthopaedic regenerative medicine
Authors: Glatt Vaida , Evans Christopher H. , Stoddart Martin J.
Published: December 2018

Regenerative rehabilitation is an emerging area of investigation that seeks to integrate regenerative medicine with rehabilitation medicine. It is based on the realization that combining these two areas of medicine at an early stage of treatment will produce a better clinical outcome than the traditional linear approach of first administering the elements of regeneration followed, after a delay, by rehabilitation. Indeed, in certain settings, a case can be made for initiating rehabilitation protocols before starting regenerative intervention. This review summarizes the contents of a workshop held during the 2018 annual meeting of the Orthopaedic Research Society. It introduced the concept of regenerative rehabilitation and then provided two orthopaedic examples drawn from the domains of cartilage repair and bone healing. Rehabilitation medicine can supply a variety of physical stimuli, including electrical stimulation, thermal stimulation and mechanical stimulation. Of these, mechanical stimulation has the most obvious relevance to orthopaedics. The mechano‐responsiveness of cartilage and bone has been known for a long time, but is poorly understood and has led to only limited clinical application. Improved bioreactor designs that allow multi‐axial loading enable new insights into the responsiveness of chondrocytes and chondroprogenitor cells to specific types of load, especially shear. Recent studies on the mechanobiology of bone healing show that modulating the mechanical environment of an experimental osseous lesion by a process of “Reverse Dynamization” soon after injury considerably enhances healing. Future studies are needed to probe the molecular mechanisms responsible for these phenomena and to translate these findings into clinical practice. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1263–1269, 2019.
Thermoresponsive hydrophobic copolymer grafted on agar microspheres for all‐aqueous bioseparations
Authors: Zhang Rui , Lv Yongqin , Tan Tianwei
Published: December 2018

Agar microspheres were prepared by water–oil emulsification and cross‐linked under alkaline condition. The thermoresponsive hydrophobic copolymer, poly(N‐isopropylacrylamide‐co‐lauryl methacrylate‐co‐acrylamide), was grafted on the agar microspheres via atom transfer radical polymerization. The agar microspheres grafted with copolymers were characterized by light microphotography, elemental analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, and X‐ray photoelectron spectroscopy. The chain lengths and hydrophobic monomer ratio of the grafting linear polymer had significant effects on the hydrophobicity and adsorption capacity of agar microspheres at different temperatures. The thermoresponsive microspheres were used for separation of proteins and showed binding and release behavior by change of temperatures without change in mobile phase composition. Thus, we suggest thermoresponsive agar microspheres as an alternative separation media for all‐aqueous bioseparations.
Hydrophilicity‐Controlled Conjugated Microporous Polymers for Enhanced Visible‐Light‐Driven Photocatalytic H2 Evolution
Authors: Wang Xuepeng , Chen Bo , Dong Wenbo , Zhang Xiaohu , Li Zibiao , Xiang Yonggang , Chen Hao
Published: December 2018

To take advantage of high surface area of network conjugated microporous polymers, four linear or network conjugated polymers L‐PDBT, L‐PDBT‐O, N‐PDBT, and N‐PDBT‐O are designed in terms of water‐compatibility, and it turned out that microporous network N‐PDBT‐O exhibited the highest hydrogen evolution rate (HER) at 366 µmol h−1 under visible light irradiation (λ > 420 nm, one of best reported pristine polymer‐based photocatalysts), which is three times higher than the corresponding linear L‐PDBT‐O. Water contact angle measurements revealed that benzothiophene‐sulfone‐based conjugated polymers display better water compatibility and adsorption, and the synergic effect of better hydrophilic surface and higher surface area of N‐PDBT‐O might eventually lead to more exposed active sites in comparison to linear L‐PDBT‐O in the H2 evolution suspension system. The hydrophilicity‐controlled strategy could be applied to design of other network conjugated microporous polymer photocatalysts in an attempt to improve the activity.
Boric Acid as a Coupling Agent for Preparation of Phenolic Resin Containing Boron and Silicon with Enhanced Char Yield
Authors: Yun Jin , Chen Lixin , Zhao Hui , Zhang Xiaofei , Ye Wenlong , Zhu Defu
Published: December 2018

In this study, an innovative, facile, and low‐cost method is developed to prepare phenolic resin (PR) containing boron and silicon (BSiPR). BSiPR is synthesized by a solvent‐free, one‐pot method using boric acid as the coupling agent instead of silane, and methyltriethoxysilane as the silicon source. The results show that boron and silicon elements are introduced into PR via BOC and BOSi structures. The char yield of the resulting resin at 800 °C is improved to 76%. The reasons for higher char yield are investigated. The formation of BOC can reduce the content of phenolic hydroxyl, which helps to decrease the weight loss. B2O3 is also formed at 400 °C, and it can prevent the release of carbon oxides. Moreover, thermally stable BOSi and SiO structures remain stable during the pyrolysis. In addition, the mechanical and ablative properties of fiber‐reinforced composites are also enhanced.
Whole‐exome sequencing reveals novel genetic variants associated with diverse phenotypes of melanoma cells
Authors: Hartman Mariusz L. , Sztiller‐Sikorska Malgorzata , Czyz Malgorzata
Published: December 2018

We have extensively studied the phenotypic heterogeneity of patient‐derived melanoma cells. Here, whole‐exome sequencing revealed novel variants of genes associated with the MAPK, NOTCH, Hippo, cell‐cycle, senescence, and ubiquitin‐dependent pathways, which could contribute to the observed phenotypic diversity between cell lines. Focusing on mutations in the MAPK pathway‐associated genes, we found BRAF (BRAFV600E) and RAS subtypes, including NRASQ61R and the rare HRASQ61R variant, and additional alterations potentially leading to different ERK1/2 activity. Both RASQ61R cell lines harbored a MEK1P124S variant and exerted a low level of phospho‐MEK1/2. Activity of the MAPK pathway was further attenuated in NRASQ61R/MEKP124S cells by trametinib, and this effect was also shown in HRASQ61R/MEKP124S melanoma cells. The observed variability in doubling time might be a consequence of diverse MAPK and PI3K/AKT pathway activities, but not exclusively, as a senescence program was also executed to different extent in distinct melanoma cell lines. Low percentages of senescent cells might result from mutations in CDKN2A, E2F3, and EZH2, and a high c‐MYC expression. Vemurafenib and trametinib induced senescence concomitantly with c‐MYC downregulation and irrespectively of CDKN2A mutation, but the EZH2S412C variant might limit senescence induction. Damaging alterations in Hippo pathway‐associated genes were accompanied with variability in the phosphorylation level of YAP1/TAZ and CTGF expression. Our study also suggests opposite activity of NOTCH2F1209V and NOTCH2N2002S variants. Additionally, we found a novel FBXW7V418M variant that retained its function in melanoma cells. The obtained molecular data might be further exploited in genotype‐phenotype relationship studies and in identifying novel biomarkers and therapies for melanomas.
Gordon Holmes Syndrome Caused by RNF216 Novel Mutation in 2 Argentinean Siblings
Authors: Calandra Cristian R. , Mocarbel Yamile , Vishnopolska Sebastian A. , Toneguzzo Vanessa , Oliveri Jaen , Cazado Enrique Carlos , Biagioli German , Turjanksi Adrián G. , Marti Marcelo
Published: December 2018

View Supplementary Video 1
Groups laud parity anniversary, bolstered by states' activities
Authors: Canady Valerie A.
Published: December 2018

Acknowledging that there is still a long way to go regarding full implementation and enforcement of the federal parity law, many in the mental health field say they are hopeful, even though 10 years have passed since the Mental Health Parity and Addiction Equity Act (MHPAEA) was signed into law. A few states have successfully passed legislation to require transparency and accountability from insurers, and other states are poised to continue that move in upcoming legislative sessions, they said.
Bill would prohibit seclusion, limit restraint in schools
Authors: Canady Valerie A.
Published: December 2018

Federal legislation to establish strong federal standards to prohibit the use of seclusion and to limit restraint in federally funded schools, and improve the safety of students and school staff, has been introduced by House lawmakers. The bill would also ensure parents are informed when their child is physically restrained.
A pedicled split extended vertical deep inferior epigastric (s‐vDIEP) flap and an adipo‐dermal thigh local flap for the reconstruction of the medial thigh compartment after sarcoma resection: A case report
Authors: Scaglioni Mario F. , Giunta Gabriele , Barth Andrè A. , Giovanoli Pietro
Published: December 2018

Large upper medial thigh defects in prior irradiated tissue require challenging reconstructions. Several techniques have been reported to reconstruct this region and according to the literature, pedicled perforator flaps are the first reconstructive option. The anterolateral thigh flap is considered the gold standard, while surprisingly the pedicle deep inferior epigastric (DIEP) flap in vertical fashion has not been frequently employed, if compared with its muscular counterpart, the pedicle vertical rectus abdomins flap (vRAM). We report a case of a multilayered flaps reconstruction of the left medial thigh after an excision of a sarcoma involving the whole adductors compartment. A 75‐year‐old male patient underwent a free margins resection of the sarcoma. After the resection, a soft tissue defect of 24 cm × 14 cm × 14 cm spreading from the groin to the medial tuberosity of the tibia, was left. We performed a reconstructive technique based on a pedicled split extended vertical deep inferior epigastric (s‐vDIEP) flap and an adipo‐dermal thigh local flap in order to fill and cover the thigh defect. The s‐vDIEP had 2 islands: a cranial de‐epithelialized island to fill the dead space and a caudal for the skin closure. The postoperative follow‐up was complicated by seroma formation and it was managed by sclerotherapy and at the 6 months follow‐up the patient showed good cosmetic and functional outcomes with no sign of tumor relapse. Our result suggests that the proposed multilayered reconstruction may be employed for the restoration of large and deep upper medial thigh defects.
Can a channelized Hotelling observer assess image quality in acquired mammographic images of an anthropomorphic breast phantom including image processing?
Authors: Balta C. , Bouwman R. W. , Sechopoulos I. , Broeders M. J. M. , Karssemeijer N. , van Engen R. E. , Veldkamp W. J. H.
Published: December 2018

Purpose

To study the feasibility of a channelized Hotelling observer (CHO) to predict human observer performance in detecting calcification‐like signals in mammography images of an anthropomorphic breast phantom, as part of a quality control (QC) framework.

Methods

A prototype anthropomorphic breast phantom with inserted gold disks of 0.25 mm diameter was imaged with two different digital mammography x‐ray systems at four different dose levels. Regions of interest (ROIs) were extracted from the acquired processed and unprocessed images, signal‐present and signal‐absent. The ROIs were evaluated by a CHO using four different formulations of the difference of Gaussian (DoG) channel sets. Three human observers scored the ROIs in a two‐alternative forced‐choice experiment. We compared the human and the CHO performance on the simple task to detect calcification‐like disks in ROIs with and without postprocessing. The proportion of correct responses of the human reader (PCH) and the CHO (PCCHO) was calculated and the correlation between the two was analyzed using a mixed‐effect regression model. To address the signal location uncertainty, the impact of shifting the DoG channel sets in all directions up to two pixels was evaluated. Correlation results including the goodness of fit (r2) of PCH and PCCHO for all different parameters were evaluated.

Results

Subanalysis by system yielded strong correlations between PCH and PCCHO, with r2 between PCH and PCCHO was found to be between 0.926 and 0.958 for the unshifted and between 0.759 and 0.938 for the shifted channel sets, respectively. However, the linear fit suggested a slight system dependence. PCCHO with shifted channel sets increased CHO performance but the correlation with humans was decreased. These correlations were not considerably affected by of the DoG channel set used.

Conclusions

There is potential for the CHO to be used in QC for the evaluation of detectability of calcification‐like signals. The CHO can predict the PC of humans in images of calcification‐like signals of two different systems. However, a global model to be used for all systems requires further investigation.
Three‐dimensional echo planar spectroscopic imaging for differentiation of true progression from pseudoprogression in patients with glioblastoma
Authors: Verma Gaurav , Chawla Sanjeev , Mohan Suyash , Wang Sumei , Nasrallah MacLean , Sheriff Sulaiman , Desai Arati , Brem Steven , O'Rourke Donald M. , Wolf Ronald L. , Maudsley Andrew A. , Poptani Harish
Published: December 2018

Accurate differentiation of true progression (TP) from pseudoprogression (PsP) in patients with glioblastomas (GBMs) is essential for planning adequate treatment and for estimating clinical outcome measures and future prognosis. The purpose of this study was to investigate the utility of three‐dimensional echo planar spectroscopic imaging (3D‐EPSI) in distinguishing TP from PsP in GBM patients. For this institutional review board approved and HIPAA compliant retrospective study, 27 patients with GBM demonstrating enhancing lesions within six months of completion of concurrent chemo‐radiation therapy were included. Of these, 18 were subsequently classified as TP and 9 as PsP based on histological features or follow‐up MRI studies. Parametric maps of choline/creatine (Cho/Cr) and choline/N‐acetylaspartate (Cho/NAA) were computed and co‐registered with post‐contrast T1‐weighted and FLAIR images. All lesions were segmented into contrast enhancing (CER), immediate peritumoral (IPR), and distal peritumoral (DPR) regions. For each region, Cho/Cr and Cho/NAA ratios were normalized to corresponding metabolite ratios from contralateral normal parenchyma and compared between TP and PsP groups. Logistic regression analyses were performed to obtain the best model to distinguish TP from PsP. Significantly higher Cho/NAA was observed from CER (2.69 ± 1.00 versus 1.56 ± 0.51, p = 0.003), IPR (2.31 ± 0.92 versus 1.53 ± 0.56, p = 0.030), and DPR (1.80 ± 0.68 versus 1.19 ± 0.28, p = 0.035) regions in TP patients compared with those with PsP. Additionally, significantly elevated Cho/Cr (1.74 ± 0.44 versus 1.34 ± 0.26, p = 0.023) from CER was observed in TP compared with PsP. When these parameters were incorporated in multivariate regression analyses, a discriminatory model with a sensitivity of 94% and a specificity of 87% was observed in distinguishing TP from PsP. These results indicate the utility of 3D‐EPSI in differentiating TP from PsP with high sensitivity and specificity.
Determination of gait parameters in real‐world environment using low‐cost inertial sensors
Authors: Mundt Marion , Thomsen Wolf , Bamer Franz , Makert Bernd
Published: December 2018

The ageing society causes an increasing need for gait monitoring in daily life to preserve the mobility of older people. Therefore, flexible low‐cost and easy‐to‐apply sensor networks are necessary. This study evaluates two in‐house developed inertial sensors for their capability of detecting spatial and temporal parameters of gait by using a time‐warping algorithm for stride segmentation. Thereby, impaired or wheeled walker supported gait can be analysed using a patient specific template. The results prove the capability to exclude sequences from the motion that do not correspond to strides and to detect spatio‐temporal parameters reliably. For the application to geriatric patients, however, further research is necessary.
Characterization of the frequency‐dependent properties of damping materials
Authors: Duvigneau Fabian , Spannan Lars , Gavila Lloret Maria , Woschke Elmar , Gabbert Ulrich
Published: December 2018

In this paper an experimental method for determining the frequency‐dependent stiffness and damping properties is presented. The aim is to obtain valid input parameters for a simulation model that considers the most important effects of typical damping materials without the necessity of poroelastic material formulations, which require at least five different input parameters. These parameters are difficult and expensive to determine experimentally. Moreover, the determination procedure is not very robust and the results can easily vary [1]. Additionally, such parameters are often phenomenological without having a physical meaning. For these reasons, it is promising to use a simpler material model based on frequency‐dependent stiffness and damping parameters within numerical simulations in order to be able to predict the acoustic behavior of complex systems with different damping and insulation treatments sufficiently.
Adaptive numerical integration of broken finite cells based on moment fitting applied to finite strain problems
Authors: Hubrich Simeon , Düster Alexander
Published: December 2018

In the finite cell method (FCM) which is based on the fictitious domain approach the numerical integration of broken cells represents a major challenge. Commonly, an adaptive integration scheme is used which, usually, results in a large number of integration points and thus increases the numerical effort, especially for nonlinear applications. To reduce the number of integration points, we present an adaptive scheme which is based on moment fitting. Thereby, we introduce an approach based on Lagrange polynomials which avoids the necessity of solving the moment fitting equation system. We study the performance of this integration method considering two numerical examples for finite strain problems of the FCM.
A general framework for the thermodynamically consistent time integration of open nonlinear thermoelastic systems
Authors: Schiebl Mark , Betsch Peter
Published: December 2018

This work deals with Energy‐Momentum‐Entropy (EME) consistent methods of open thermoelastic systems. While Energy‐Momentum (EM) preserving integrators are well‐known for conservative mechanical systems, Romero introduced in [1] the class of thermodynamically consistent (TC) integrators for coupled thermomechanical systems, which further respect symmetries of the underlying coupled system and are capable of conserving associated momentum maps and can therefore also be termed EME schemes in analogy to EM schemes for conservative systems. As mathematical framework for the geometric structure of the non‐equilibrium thermodynamics the GENERIC (General Equation for Non‐Equilibrium Reversible‐Irreversible Coupling) framework, originally introduced for complex fluids in [2], is used. Since the GENERIC framework does not depend on a specific choice of the thermodynamical state variables [3], we explore the structure of the GENERIC framework using the entropy density (see e.g. [4]), the absolute temperature (see e.g. [5]) and further the internal energy density as thermodynamical state variable. Applying the notion of a discrete gradient in the sense of [6] leads to an EME integrator. As boundary conditions rely on the specific choice of the thermodynamical state variable we extend the GENERIC framework to be suitable for open systems following the procedure in [7].
Isogeometric Analysis with Trimmed CAD Models
Authors: Marussig Benjamin
Published: December 2018

Trimmed CAD models are the most popular geometry representation in engineering design, but their direct application to an isogeometric analysis can lead to ill‐conditioned system matrices. An approach is presented that effectively resolves this issue by combining so‐called extended B‐splines with a local refinement procedure.
Modelling and Simulation of the Coating Process on Open Porous Metal Foams
Authors: Grill Christine , Jung Anne , Diebels Stefan
Published: December 2018

Based on an increasing demand of energy and raw materials, resources should be used more efficiently. Therefore, multifunctional materials and lighter constructions, which can endure higher payloads, are needed. Cellular materials like metal foams are bionic, multifunctional materials, which can be optimised by a coating of the foam structure. Due to this coating via electrodeposition, the material properties per unit mass can be optimised. In consequence of the mass transport limitation inside the foam during the electrodeposition process, there occurs an inhomogeneous coating thickness distribution. To obtain a homogeneous coating thickness, in this project the factors are studied and simulated, which influence the electrochemical coating process. The electrodeposition process can be described by an ion source at the anode, the mass transport from anode to cathode and an ion sink at the cathode. The mass transport and the deposition process are characterised by the continuity equation with convection, diffusion, migration, a source term and a sink term. In this contribution, the factors influencing the coating thickness are investigated by numerical simulation to provide a homogeneous coating thickness. A material model is developed coupling mass transport with electrodeposition. A finite difference approach is used to simulate the ion concentration distribution inside the foam.
Experimental study and discrete element simulation of auger dosing of different pharmaceutical powders
Authors: El Kassem Bilal , Brinz Thomas , Heider Yousef , Markert Bernd
Published: December 2018

In pharmaceutical solid dosage forms development, the physical properties of powders play a significant role in their flowability and help in understanding the flow behavior and optimizing the design of powder handling equipment. In particular, powder flow depends strongly on the interparticulate interactions between the particles, where with more interactions, i.e. internal friction between particles, the less is the powder flowability and, thus, more power is required to accelerate the flow in the dosing machine.

One of the main goals of this project is to implement high‐speed first‐in‐first‐out powder auger dosing of small quantities and accomplishing high dosing accuracy. Shear cell analysis and empirical methods are used to characterize powder flow. Different parameters including powder properties, geometry design and operating process conditions are used and altered accordingly based on design of experiments (DoE). Experimental studies and discrete element method (DEM) simulations on dosing different pharmaceutical powders are performed.
Numerically robust two‐scale full‐field finite strain crystal plasticity simulations of polycrystalline materials
Authors: Kochmann Julian , Wulfinghoff Stephan , Svendsen Bob , Reese Stefanie
Published: December 2018

The purpose of this work is the derivation of a numerically robust algorithmic formulation for the computation of the overall consistent algorithmic tangent moduli for the two‐scale modeling of heterogeneous materials with non‐linear constitutive behavior at finite strains. The underlying concept is a perturbation method. In contrast to existing numerical tangent computation algorithms, the proposed method yields the exact tangent using only six (instead of nine) perturbations (three in 2d). As an example, the FE‐FFT‐based approach by [6] is employed to predict the local and overall mechanical behavior of elasto‐viscoplastic polycrystals in a macroscopic Cook's membrane problem setting.
Characterization of Brake Shims Using Analytical Constrained Layer Damping Theories
Authors: Schmid Dominik , Gräbner Nils , von Wagner Utz
Published: December 2018

Shims in automotive brake systems are applied to suppress brake squeal resulting from self‐excited vibrations. These composite structures consist of thin metal plates and elastomer layers having high damping potential. The characterization and subsequent selection of shims is mainly based on a wide range of experimental investigations so far. To reduce measuring efforts significantly a systematic modeling of shims is focused. Therefore, approaches from literature describing surface damping treatments analytically are considered. The damping effect is mainly based on the shearing of the viscoelastic core which is taken into account by the applied theory. The dissipation potential is characterized by the complex shear modulus of the elastomer layer. Hence, sandwich beam theories enable the prediction of natural frequencies and in particular loss factors of bending mode shapes. In this contribution shims bonded on rectangular steel plates are examined. The main focus is on the determination of rheological influencing variables as well as the impact of boundary conditions in detail. Moreover, the impact of the shim length on the damping behavior is investigated experimentally.
Guided wave‐based damage detection in solids using computational intelligence
Authors: Hesser Daniel Frank , Markert Bernd
Published: December 2018

The field of structural health monitoring focuses on the non‐destructive evaluation of structures during on‐going operation. In this paper, the application of elastic guided waves in solids is discussed and applied to monitor an aluminium plate. The interaction of waves with structural features and uncertainties results into a unique wave field, which can be achieved by bonding piezoelectric sensors on the surface. These sensors allow a controlled excitation and acquisition of waves in structural components. In this study, the acquired data is processed by the help of computational intelligence. Computational intelligence enables the ability to learn wave behaviours from data of undamaged as well as damaged structures. Once the training process is completed, the trained system can be applied under operational conditions and will continuously monitor the structure and detect the location of damage.
Modelling the anisotropic in‐plane and out‐of‐plane elastic‐plastic response of paper
Authors: Alajami Ahmad , Li Yujun , Simon Jaan‐Willem
Published: December 2018

Laminated paperboard is one of the main materials used in packaging products. The technical processes used for manufacturing such materials lead to a sepcial fiber structure that gives the material anisotropic behavior which can be observed in experiments. Two different directions can be distinguished;the in‐plane and the out‐of‐plane directions, which both experience an elastic‐plasctic behavior, where a permanent deformation is observed after unloading in both directions. The out‐of‐plane behavior includes additional aspects such as the densification and internal friction effects. These effects are significant to investigate especially in the large deformations range, which can be observed during different forming processes of the paperboard. For these reasons, an in‐plane and an out‐of‐plane models were introudced. Each model works independently from the other one. The models were formulated based on the finite strain elasto‐plasticity framework, which gives the possiblity to investigate the behavior of paperboard under large deformations. As a result, the current model was able to represent the main aspects of the behavior of paperboard in both in‐plane and out‐of‐plane directions.
On the back calculation of material strength values from strength test results
Authors: Schagerl Martin , Grillenberger Markus
Published: December 2018

The determination of material strength parameters from structural test measurements yields in general an inverse problem. The measured test values are e.g. loads and displacements applied on the specimen. The unknown material parameters are e.g. local stress values at particular strain states. Naturally, material models should only contain material parameters which can be identified by such back calculation. However, if material models want to be practically useful, the back calculation should be a simple procedure, which is derived from adapted analytical and numerical models, and where the material parameters are gained in a most direct way. In a complete approach the introduction of a new constitutive model is accompanied with the specification of an according test setup and a validated evaluation procedure, with which the engineer can determine the occurring material parameters. The current article discusses this issue on hand of two simple, but non‐standard material strength data for metals: First, the flow curve under pure shear, which is determined by using a plane torsion test rig, and second, the compressive strength under high strain rates, which is determined by using a cam drive test rig. Both, analytical considerations and numerical Finite Element simulations are used for back calculation.
Micromechanical behavior of UHPC under cyclic bending‐tensile loading in consideration of the influence of the concrete edge zone
Authors: Harenberg Stefan , Caggiano Antonio , Koenig Andreas , Said Diego , Gilka‐Bötzow Albrecht , Schultz‐Cornelius Milan , Yang Sha , Pahn Matthias , Dehn Frank , Koenders Eddie
Published: December 2018

This paper provides preliminary results of a research study on the fatigue behavior of Ultra‐High‐Performance Concrete (UHPC). Results of an experimental campaign, performed at the Department of Concrete Structures and Structural Engineering of the TU‐Kaiserslautern, are firstly proposed. The heterogeneous meso‐structure and material degradation of UHPC are studied through cyclic bending‐tensile tests. A test set‐up is specially developed at the TU‐Kaiserslautern to perform such activities. Particularly, different upper stress cycles (namely, cycle reversals) characterized by different force/stress amplitudes are considered and analyzed. The influence of the edge zone on the stress cycles is tested on notched and normal specimens while the results are used for composing a so‐called “Wöhler curve” of the materials' fatigue behavior. Damage progress during loading is monitored by means of a Digital Image Correlation system (DIC) and the results are used for improving the measurement accuracy. Based on these results, macroscopic and mesoscale simulations are performed at the TU‐Darmstadt‘s Institute of Construction and Building Materials. A meso‐mechanical approach for the numerical analysis of UHPC specimens subjected to low‐ and high‐cycle fatigue actions will be presented. The possibilities of modeling the material fracture response induced by fatigue is taken into account by means of a systematic use of zero‐thickness interface elements equipped with a fracture‐based model and combined with a continuous damage constitutive law. A plastic‐damage based model for concrete subjected to cyclic loading is developed combining the concept of fracture‐energy theories with a stiffness degradation, representing the key phenomenon occurring in concrete under cyclic responses. The experimental and numerical activities proposed in this paper stem out from the DFG Priority Program 2020 Project “Cyclic Damage Processes in High‐Performance Concretes in the Experimental Virtual Lab”.
On the Kinematics of Contact Line Motion
Authors: Fricke Mathis , Köhne Matthias , Bothe Dieter
Published: December 2018

We investigate the moving contact line problem for two‐phase incompressible flows by a kinematic approach. The key idea is to derive an evolution equation for the contact angle assuming the transporting velocity field to be given. It turns out that the resulting equation expresses the time derivative of the contact angle in terms of the velocity gradient at the solid wall. Together with the additionally imposed boundary conditions for the velocity, it yields a more specific form of the contact angle evolution. In this paper we consider the Navier slip boundary condition, which is frequently used for the modeling of moving contact lines. Exploiting furthermore the interfacial transmission condition for the viscous stress, we derive an explicit form of the contact angle evolution for sufficiently regular solutions. In the absence of phase change it only involves the contact line velocity and the slip length from the Navier condition. From this equation we can read off the qualitative behavior of the contact angle evolution for sufficiently regular solutions to these models, which turns out to be unphysical.
Fault diagnosis using Probability of Detection (POD)‐based sensor/information fusion for vibration‐based analysis of elastic structures
Authors: Ameyaw Daniel Adofo , Rothe Sandra , Söffker Dirk
Published: December 2018

The Probability‐of‐Detection (POD) measure quantifies the performance of a measurement device to nondestructive testing taking into account statistical variability. The time and cost involved have given rise to Model‐Assisted POD to improve the effectiveness of POD models with little or no specimen testing. Similar criteria regarding capabilities of FDI (Fault Detection and Isolation) or diagnostic approaches applied to vibration‐based analysis are currently not known. This results from complexity of the dynamical behaviors in relation to faults, sensor positions (observability), and feature extraction tasks. In this contribution the complexity of POD‐based analysis applied to fault detection of elastic mechanical structures is examined. Based on experimental results of mechanical modifications on an elastic beam, the POD of different FDI‐procedures are examined. Different sensor types are used for eigenfrequency analysis. Depending on the modes considered it can be shown why this classical approach often does not lead to satisfying results. To fuse the POD values, suitable assumptions in combination with a new method are applied to eigenfrequency‐based analysis as detection task.
Value diversity and conservation conflict: Lessons from the management of red grouse and hen harriers in England
Authors: St John Freya A. V. , Steadman Janna , Austen Gail , Redpath Steve M.
Published: December 2018

Conflicts between people over wildlife management are damaging, widespread, and notoriously difficult to resolve where people hold different values and worldviews. Cognitive approaches examining steps from human thought to action can help us understand conflict and explore strategies for their management.

We focused on the conflict between hunters and conservationists over the management of red grouse (Lagopus lagopus scoticus) and hen harriers (Circus cyaneus) in the English uplands which represents a classic, persistent conflict, where human dimensions are poorly understood.

Guided by conceptual frameworks from social and environmental psychology, we conducted a questionnaire‐based study to assess wildlife value orientations of key stakeholders. We quantified attitudes towards hen harriers, grouse shooting, gamekeepers, and raptor conservationists. We also measured support/opposition for harrier management strategies in England and investigated trust in the responsible government authority.

We present data from 536 respondents from field sport or nature conservation organizations. Respondents were categorized according to the primary objectives of their affiliated organization: Field sport (i.e., hunters), Non‐raptor, Pro‐raptor, and Pro‐bird (i.e., organizations promoting conservation of birds excluding raptors, raptors specifically, or birds generally).

Utilitarian value orientations were prominent among Field sport and Non‐raptor respondents. Most Pro‐raptor and Pro‐bird participants held mutualist value orientations, indicating they did not support shooting or management of wildlife.

As suggested by the cognitive hierarchy, we found strong correlations between attitude and support for management options, our proxy for behaviour.

Pro‐bird affiliates showed clear preference for less invasive management, and along with Pro‐raptor respondents did not support brood management (removal and later release of eggs/young when harrier density is high). Field sport individuals expressed a degree of support for all management types. Trust in Natural England was limited.

Understanding value orientations and attitudes of stakeholders helps explain differences in levels of support for management approaches. Our study highlighted strongly divergent beliefs. Such positions are hard to change. Increasing the level of ecological knowledge alone is unlikely to facilitate conflict management. Instead, conflict management would benefit from combining such knowledge with a focus on relationships, deliberation, and trust in addition to exploring comanagement interventions.

A plain language summary is available for this article.
Increased risk for aseptic meningitis after amoxicillin or amoxicillin‐clavulanic acid in males: A signal revealed by subset disproportionality analysis within a global database of suspected adverse drug reactions
Authors: Chandler Rebecca E.
Published: December 2018

Purpose

Drug‐induced aseptic meningitis (DIAM) is an inflammation of the membranes of the central nervous system caused by certain medications. It is a rare clinical entity whose risk factors are not yet fully elucidated. A local pattern of disproportionality within a global database of suspected adverse drug reactions (ADRs) revealed an increased reporting of aseptic meningitis and amoxicillin‐clavulanic acid (AC) in males. The aim of this report is to explore the clinical probability of a higher risk in males to support the use of statistical methods to identify subgroups at risk for adverse drug reactions.

Methods

Disproportionality analysis was performed for all drug‐adverse event (AE) pairs in the entire database and for the subsets of males and females. AC‐aseptic meningitis was highlighted for an increased disproportionality in the male subgroup in the absence of an elevated disproportionality measure for the database overall. A clinical review was undertaken.

Results

Clinical review revealed a similar statistical pattern of gender difference observed for amoxicillin, evidence to suggest a delayed type 4 hypersensitivity reaction with Th1 cells as a mechanism for amoxicillin‐aseptic meningitis, the existence of sex differences in immune responses (Th1/Th2), and an analogous increased risk of drug‐induced liver injury by AC in males.

Conclusions

Subgroup disproportionality analysis has revealed a larger than expected number of reports of aseptic meningitis after amoxicillin and AC in males. Evidence synthesis supports the statistical finding. Further exploration of spontaneous databases with more extensive analyses could usher in a new era of “precision pharmacovigilance.”