bluuebunny/crossref_metadata_2025 huggingface dataset:
CYRI (FAM49) proteins are local inhibitors of Scar/WAVE induced lamellipodia that bind directly to active Rac1
Authors: Fort Loic , Batista Jose , Thomason Peter , Spence Heather J. , Greaves Jennifer , Martin Kirsty J. , Anderson Kurt I. , Brown Peter , Lilla Sergio , Neilson Matthew P. , Tafelmeyer Petra , Zanivan Sara , Ismail Shehab , Tomkinson Nicholas C.O. , Chamberlain Luke H. , Insall Robert H. , Machesky Laura M.
Published: November 2017

Actin-based protrusions driving cell migration are reinforced through positive feedback, but it is unclear how the cell restricts the eventual size of a protrusion or limits positive signals to cause splitting or retraction. We have identified an evolutionarily conserved regulator of the protrusion machinery, which we name CYRI (CYFIP-relatedRacinteracting) protein. CYRI shows sequence similarity to the Scar/WAVE complex member CYFIP in aDomain ofUnknownFunction, DUF1394. CYRI binds specifically to activated Rac1 via a common motif shared with CYFIP, establishing DUF1394 as a new Rac1 binding domain. CYRI-depleted cells have broad, Scar/WAVE-enriched lamellipodia and enhanced Rac1 signaling. Conversely, CYRI overexpression suppresses spreading and dramatically sharpens protrusions into unproductive needles. CYRI proteins use dynamic inhibition of Scar/WAVE induced actin to focus positive protrusion signals and regulate pseudopod complexity. CYRI behaves like a “local inhibitor” predicted and described in widely accepted mathematical models, but not previously identified in living cells.
Multiple inputs ensure yeast cell size homeostasis during cell cycle progression
Authors: Garmendia-Torres Cecilia , Tassy Olivier , Matifas Audrey , Molina Nacho , Charvin Gilles
Published: November 2017

Coordination of cell growth and division is essential for proper cell function. In budding yeast, although some molecular mechanisms responsible for cell size control during G1 have been elucidated, the mechanism by which cell size homeostasis is established and maintained throughout the cell cycle remains to be discovered. Here, we developed a new technique based on quantification of histone levels to monitor cell cycle progression in individual yeast cells with unprecedented accuracy. Our analysis establishes the existence of a strong mechanism controlling bud size in G2/M that prevents premature entry into mitosis, and contributes significantly to the overall control of size variability during the cell cycle. While most G1/S regulation mutants do not display any strongly impaired size homeostasis, mutants in which B-type cyclin regulation is altered display large cell-to-cell size variability. Our study thus demonstrates that size homeostasis is not controlled by a G1-specific mechanism but is likely to be an emergent property resulting from the integration of several mechanisms, including the control of cyclin B-Cdk activity, that coordinate cell and bud growth with division.
CRISPR-Cas12a target binding unleashes single-stranded DNase activity
Authors: Chen Janice S. , Ma Enbo , Harrington Lucas B. , Tian Xinran , Doudna Jennifer A.
Published: November 2017

CRISPR-Cas12a (Cpf1) proteins are RNA-guided DNA targeting enzymes that bind and cut DNA as components of bacterial adaptive immune systems. Like CRISPR-Cas9, Cas12a can be used as a powerful genome editing tool based on its ability to induce genetic changes in cells at sites of double-stranded DNA (dsDNA) cuts. Here we show that RNA-guided DNA binding unleashes robust, non-specific single-stranded DNA (ssDNA) cleavage activity in Cas12a sufficient to completely degrade both linear and circular ssDNA molecules within minutes. This activity, catalyzed by the same active site responsible for site-specific dsDNA cutting, indiscriminately shreds ssDNA with rapid multiple-turnover cleavage kinetics. Activation of ssDNA cutting requires faithful recognition of a DNA target sequence matching the 20-nucleotide guide RNA sequence with specificity sufficient to distinguish between closely related viral serotypes. We find that target-dependent ssDNA degradation, not observed for CRISPR-Cas9 enzymes, is a fundamental property of type V CRISPR-Cas12 proteins, revealing a fascinating parallel with the RNA-triggered general RNase activity of the type VI CRISPR-Cas13 enzymes.

One Sentence Summary

Cas12a (Cpf1) and related type V CRISPR interference proteins possess non-specific, single-stranded DNase activity upon activation by guide RNA-dependent DNA binding.
Migrating hydrogen in 2,4,6-triaminopyrimidinium(1+)
x
hydrogen trioxofluorophosphate(−)
x
monohydrate/2,4,6-triaminopyrimidinium(2+)1–x
trioxofluorophosphate(2–)1–x
monohydrate (0.0 < x < 0.73) with changing temperature
Authors: Matulková Irena , Fábry Jan , Němec Ivan , Císařová Ivana , Vaněk Přemysl
Published: November 2017

The data of the title structure of 2,4,6-triaminopyrimidinium(1+)
x
hydrogen trioxofluorophosphate(1−)
x
monohydrate/2,4,6-triaminopyrimidinium(2+)1−x
trioxofluorophosphate(2−)1−x
monohydrate (0.0 < x < 0.73), with the sum formula C4H11FN5O4P, were collected in 10 K intervals between 290 and 150 K, as well as at 100 K. The most interesting feature is the presence of a moderate though still strong O—H...N/O...H—N hydrogen bond. Its bridging H atom was found to be disordered over two positions in the temperature interval 290–220 K, with the larger occupation towards the O atom. The occupation in the latter position decreased with decreasing temperature, though not monotonously. At 210 K and below, the difference electron-density maps showed just one maximum which was closer to the N atom. Though difference scanning calorimetry (DSC) revealed no anomaly in the interval 303–93 K, the dependence of the length of the unit-cell axes b and c on temperature showed a kink in the slope at about 190 K. The N...O distance of the mentioned hydrogen bond or the occupational parameter of the electron density of the disordered H atom indicate less pronounced anomalies for the temperatures 270 and 230 K. The cation and the anion, as well as the water molecules, form layers which are parallel to (10\overline{1}) and which are interconnected by O—H...N (in the interval 290–220 K), N—H...O and O—H...O hydrogen bonds of moderate strength. The layers are arranged into centrosymmetric double layers in which the F atoms are directed outwards. The layers are interconnected by water–acid O—H...O hydrogen bonds, weak N—H...F interactions and π-electron ring...π-electron ring interactions. The dependence of P—F bond lengths on bonding properties of the trioxofluorophosphate or hydrogen trioxofluorophosphate anions is discussed. It has been recognized that a carbon-bonded F atom avoids participation in a hydrogen-bond pattern; however, this property seems to be also common to fluorine bonded to P, As and S, especially if an oxygen ligand is also present in a molecule. The deposited material contains an overview of the determined structures with trioxofluorophosphate or hydrogen trioxofluorophosphate anions.
Solid-state structure of cyclic dipeptides: an X-ray and computational study of cis- and trans-diketopiperazines of N-methyl-phenylalanine with the thia-pipecolic acids and thia-prolines
Authors: Budesinsky Milos , Cisarova Ivana , Borremans Frans , Martins Jose C. , Pauwels Ewald
Published: November 2017

Ten new crystal structures of cis and trans bicyclic diketopiperazines (DKPs) of thia-pipecolic acid (with sulfur in the β, γ or δ position) or thia-proline (with sulfur in the β or γ position) and N-methyl phenylalanine [(NMe)Phe]: cyclo[(β-S)Pip-(NMe)Phe], cyclo[(γ-S)Pip-(NMe)Phe], cyclo[(δ-S)Pip-(NMe)Phe], cyclo[(β-S)Pro-(NMe)Phe] and cyclo[(γ-S)Pro-(NMe)Phe] were determined with X-ray crystallography. Density functional theory calculations of these molecules in the gas phase succeed in reproducing the observed molecular conformations in the crystal remarkably well. This illustrates the weak to moderate impact of intermolecular packing forces in the absence of classical N—H...O hydrogen bonds. The effect of sulfur on the geometry of the DKP ring and details of amide bond non-planarity are discussed. Molecular flexibility of the DKP ring, as estimated from the calculated deformation energies of its endocyclic ring torsion angles, is not in general the decisive factor for the occurrence of multiple symmetry independent molecules in the unit cell (Z′ > 1), though in some cases a correlation is observed.
Cobaltoceniumsulfonate
Authors: Vanicek Stefan , Wurst Klaus , Bildstein Benno
Published: November 2017

The title compound, [Co(C5H5)(C5H4O3S)], was synthesized by dediazoniation of cobaltoceniumdiazonium bis(hexafluoridophosphate) with CuCl and SO2, crystallizing as yellow platelets. Structurally, a regular cobaltocenium sandwich moiety is observed containing coplanar cyclopentadienyl rings and displaying unexceptional carbon–cobalt [2.0230 (16)–2.0452 (14) Å] and carbon–carbon [1.410 (3)–1.431 (3) Å] bond distances. In this mesoionic molecule, the cationic cobaltoceniumyl part is connected to its anionic sulfonate part by a carbon–sulfur single bond of 1.7717 (15) Å.
What drives merger behavior of firms? Strategic momentum versus bandwagons
Authors: Pangarkar Nitin
Published: November 2017

Mergers represent a common means of restructuring assets. The existing literature on mergers, however, has a strong bias towards viewing firms' decisions as outcomes of comprehensively rational processes. In this study, we propose two alternative explanations regarding mergers, namely strategic momentum and bandwagons. Both these explanations incorporate factors such as incomplete information, cognitive simplifications by managers and principal-agent issues. Bandwagon theories argue that firms will tend to imitate their close rivals regardless of whether such imitation is value-enhancing or not. Strategic momentum theory argues that firms tend to continue with strategies they have implemented in the past. Based on an exhaustive sample of acquisitions, domestic as well as international, undertaken by 43 large pharmaceutical firms based in the triad region over a period of 15 years, we find robust support for the bandwagons Mergers represent a common means of restructuring assets. The existing literature on mergers, however, has a strong bias towards viewing firms' decisions as outcomes of comprehensively rational processes. In this study, we propose two alternative explanations regarding mergers, namely strategic momentum and bandwagons. Both these explanations incorporate factors such as incomplete information, cognitive simplifications by managers and principal-agent issues. Bandwagon theories argue that firms will tend to imitate their close rivals regardless of whether such imitation is value-enhancing or not. Strategic momentum theory argues that firms tend to continue with strategies they have implemented in the past. Based on an exhaustive sample of acquisitions, domestic as well as international, undertaken by 43 large pharmaceutical firms based in the triad region over a period of 15 years, we find robust support for the bandwagons explanation. We do not find unequivocal support for the strategic momentum explanation.
Job involvement, personal characteristics and performance among white-collar employees in the kuwaiti civil service
Authors: Al-Otaibi Adam Ghazi
Published: November 2017

This study explores the effect of demographic variables, such as age, education, length of service, marital status and salary, on job involvement and examines the relationship between job involvement and job performance in a sample of 300 white-collar Kuwaiti civil service employees. Results suggest that the demographic variables have no effect on job involvement. However, the group exhibiting high job involvement did score higher in job performance, a relationship that accounted for 39% of the total variance in job performance.
Rethinking concepts, concerns, and collaboration in interorganizational relationships
Authors: Dudley Lark in S. , Sutton Jeffrey
Published: November 2017

Because increased attention is being given to the problems and possibilities associated with interdependence among organizations and sectors in theory and practice, this introduction to the symposium emphasizes the importance of a rethinking of concepts, concerns, and strategies for interorganizational and intersectorial relationships. Described are the major themes of seven articles in the symposium which address issues of accountability in contracting, the validity of the three sector model, loss of organizational identity by nonprofits, virtual organizations, subversion of values in urban development policymaking, motivation in environmental networks, and deliberation in nonprofit organizations.
The U.S. public dialogue on trade policy: An initial assessment
Authors: Geri Laura nee R.
Published: November 2017

There has been little public dialogue in the United States on the implications of the evident trend toward greater worldwide economic, social and political integration. This trend, generally termed globalization, has occurred largely as the result of political decisions by states to reduce their ability to restrict trade and investment. This article explores the barriers which may be blocking such a dialogue and several options for lowering certain of these barriers. Unless such a dialogue begins in the near future, the ability of citizens to influence these trends may lost, with uncertain effects on governmental legitimacy.
Provenance description of metadata application profiles for long-term maintenance of metadata schemas
Authors: Li Chunqiu , Sugimoto Shigeo
Published: November 2017

Purpose

Provenance information is crucial for consistent maintenance of metadata schemas over time. The purpose of this paper is to propose a provenance model named DSP-PROV to keep track of structural changes of metadata schemas.

Design/methodology/approach

The DSP-PROV model is developed through applying the general provenance description standard PROV of the World Wide Web Consortium to the Dublin Core Application Profile. Metadata Application Profile of Digital Public Library of America is selected as a case study to apply the DSP-PROV model. Finally, this paper evaluates the proposed model by comparison between formal provenance description in DSP-PROV and semi-formal change log description in English.

Findings

Formal provenance description in the DSP-PROV model has advantages over semi-formal provenance description in English to keep metadata schemas consistent over time.

Research limitations/implications

The DSP-PROV model is applicable to keep track of the structural changes of metadata schema over time. Provenance description of other features of metadata schema such as vocabulary and encoding syntax are not covered.

Originality/value

This study proposes a simple model for provenance description of structural features of metadata schemas based on a few standards widely accepted on the Web and shows the advantage of the proposed model to conventional semi-formal provenance description.
Gender bias in sentiment analysis
Authors: Thelwall Mike
Published: November 2017

Purpose

The purpose of this paper is to test if there are biases in lexical sentiment analysis accuracy between reviews authored by males and females.

Design/methodology/approach

This paper uses data sets of TripAdvisor reviews of hotels and restaurants in the UK written by UK residents to contrast the accuracy of lexical sentiment analysis for males and females.

Findings

Male sentiment is harder to detect because it is less explicit. There was no evidence that this problem could be solved by gender-specific lexical sentiment analysis.

Research limitations/implications

Only one lexical sentiment analysis algorithm was used.

Practical implications

Care should be taken when drawing conclusions about gender differences from automatic sentiment analysis results. When comparing opinions for product aspects that appeal differently to men and women, female sentiments are likely to be overrepresented, biasing the results.

Originality/value

This is the first evidence that lexical sentiment analysis is less able to detect the opinions of one gender than another.
Insight from social media use by memory institutions in New Zealand
Authors: Liew Chern Li , Oliver Gillian , Watkins Morgan
Published: November 2017

Purpose

The relatively under-documented “dark side” of participatory activities facilitated by memory institutions through social media is examined in this study. The purpose of this paper is to investigate the risks and perception of risks resulting from using social media for public engagement and participation.

Design/methodology/approach

Semi-structured interviews were conducted with fourteen representatives from the New Zealand information and cultural heritage sector who at the time of the study were holding the main responsibilities of overseeing the social media and participatory activities of the institutions they represented.

Findings

It is not evident that the growth of social web has significantly changed the way the heritage sector seeks participation. Only a small minority of the sample institutions appear to be using social web tools to build community and to enhance their heritage collections. For the majority, institutional use of social media is for creating a “chattering space”. The main concerns identified by interviewees were reputation management and the risk management process followed by most institutions appeared to be reactive, responding to problems as and when they occurred, rather than proactive about risk identification and avoidance.

Research limitations/implications

Findings are not generalisable as the sample size of thirteen institutions is relatively small and is limited to one national context.

Originality/value

Findings provide insight into largely unexplored issues relating to the development of participatory cultures by memory institutions. The paper highlights a key area where further research is needed, namely to explore whether participatory heritage should primarily be about curated viewpoints or whether it should encompass capturing living dialogues, even when conversations are potentially offensive.
A systematic review on the use of best practices for publishing linked data
Authors: Feitosa Danila , Dermeval Diego , Ávila Thiago , Bittencourt Ig Ibert , Lóscio Bernadette Farias , Isotani Seiji
Published: November 2017

Purpose

Data providers have been increasingly publishing content as linked data (LD) on the Web. This process includes guidelines (i.e. good practices) to publish, share, and connect data on the Web. Several people in different areas, for instance, sciences, medicine, governments and so on, use these practices to publish data. The LD community has been proposing many practices to aid the publication of data on the Web. However, discovering these practices is a costly and time-consuming task, considering the practices that are produced by the literature. Moreover, the community still lacks a comprehensive understanding of how these practices are used for publishing LD. Thus, the purpose of this paper is to investigate and better understand how best practices support the publication of LD as well as identifying to what extent they have been applied to this field.

Design/methodology/approach

The authors conducted a systematic literature review to identify the primary studies that propose best practices to address the publication of LD, following a predefined review protocol. The authors then identified the motivations for recommending best practices for publishing LD and looked for evidence of the benefits of using such practices. The authors also examined the data formats and areas addressed by the studies as well as the institutions that have been publishing LD.

Findings

In summary, the main findings of this work are: there is empirical evidence of the benefits of using best practices for publishing LD, especially for defining standard practices, integrability and uniformity of LD; most of the studies used RDF as data format; there are many areas interested in dissemination data in a connected way; and there is a great variety of institutions that have published data on the Web.

Originality/value

The results presented in this systematic review can be very useful to the semantic web and LD community, since it gathers pieces of evidence from the primary studies included in the review, forming a body of knowledge regarding the use best practices for publishing LD pointing out interesting opportunities for future research.
Optimising the process parameters of selective laser melting for the fabrication of Ti6Al4V alloy
Authors: Li Zhonghua , Kucukkoc Ibrahim , Zhang David Z. , Liu Fei
Published: November 2017

Purpose

Surface roughness is an important evaluation index for industrial components, and it strongly depends on the processing parameters for selective laser molten Ti6Al4V parts. This paper aims to obtain an optimum selective laser melting (SLM) parameter set to improve the surface roughness of Ti6Al4V samples.

Design/methodology/approach

A response surface methodology (RSM)-based approach is proposed to improve the surface quality of selective laser molten Ti6Al4V parts and understand the relationship between the SLM process parameters and the surface roughness. The main SLM parameters (i.e. laser power, scan speed and hatch spacing) are optimized, and Ti6Al4V parts are manufactured by the SLM technology with no post processes.

Findings

Optimum process parameters were obtained using the RSM method to minimise the roughness of the top and vertical side surfaces. Obtained parameter sets were evaluated based on their productivity and surface quality performance. The validation tests have been performed, and the results verified the effectivity of the proposed technique. It was also shown that the top and vertical sides must be handled together to obtain better top surface quality.

Practical implications

The obtained optimum SLM parameter set can be used in the manufacturing of Ti6Al4V components with high surface roughness requirement.

Originality/value

RSM is used to analyse and determine the optimal combination of SLM parameters with the aim of improving the surface roughness quality of Ti6Al4V components, for the first time in the literature. Also, this is the first study which aims to simultaneously optimise the surface quality of top and vertical sides of titanium alloys.
Development of predictive models for effective process parameter selection for single and overlapping laser clad bead geometry
Authors: Aggarwal Kush , Urbanic R.J. , Saqib Syed Mohammad
Published: November 2017

Purpose

The purpose of this work is to explore predictive model approaches for selecting laser cladding process settings for a desired bead geometry/overlap strategy. Complementing the modelling challenges is the development of a framework and methodologies to minimize data collection while maximizing the goodness of fit for the predictive models. This is essential for developing a foundation for metallic additive manufacturing process planning solutions.

Design/methodology/approach

Using the coaxial powder flow laser cladding method, 420 steel cladding powder is deposited on low carbon structural steel plates. A design of experiments (DOE) approach is taken using the response surface methodology (RSM) to establish the experimental configuration. The five process parameters such as laser power, travel speed, etc. are varied to explore their impact on the bead geometry. A total of three replicate experiments are performed and the collected data are assessed using a variety of methods to determine the process trends and the best modelling approaches.

Findings

There exist unpredictable, non-linear relationships between the process parameters and the bead geometry. The best fit for a predictive model is achieved with the artificial neural network (ANN) approach. Using the RSM, the experimental set is reduced by an order of magnitude; however, a model with R2 = 0.96 is generated with ANN. The predictive model goodness of fit for a single bead is similar to that for the overlapping bead geometry using ANN.

Originality/value

Developing a bead shape to process parameters model is challenging due to the non-linear coupling between the process parameters and the bead geometry and the number of parameters to be considered. The experimental design and modelling approaches presented in this work illustrate how designed experiments can minimize the data collection and produce a robust predictive model. The output of this work will provide a solid foundation for process planning operations.
Effect of build orientation on the surface quality, microstructure and mechanical properties of selective laser melting 316L stainless steel
Authors: Alsalla Hamza Hassn , Smith Christopher , Hao Liang
Published: November 2017

Purpose

The purpose of this paper is to investigate the density, surface quality, microstructure and mechanical properties of the components of the selective laser melting (SLM) parts made at different building orientations. SLM is an additive manufacturing technique for three-dimensional parts. The process parameters are known to affect the properties of the eventual part. In this study, process parameters were investigated in the building of 316L structures at a variety of building orientations and for which the fracture toughness was measured.

Design/methodology/approach

Hardness and tensile tests were carried out to evaluate the effect of consolidation on the mechanical performance of specimens. Optical and electron microscopy were used to characterise the microstructure of the SLM specimens and their effects on properties relating to fracture and the mechanics. It was found that the density of built samples is 96 per cent, and the hardness is similar in comparison to conventional material.

Findings

The highest fracture toughness value was found to be 176 MPa m^(1/2) in the oz. building direction, and the lowest value was 145 MPa m^(1/2) in the z building direction. This was due to pores and some cracks at the edge, which are slightly lower in comparison to a conventional product. The build direction does have an effect on the microstructure of parts, which subsequently has an effect upon their mechanical properties and surface quality. Dendritic grain structures were found in oz. samples due to the high temperature gradient, fast cooling rate and reduced porosity. The tensile properties of such parts were found to be better than those made from conventional material.

Originality/value

The relationship between the process parameters, microstructure, surface quality and toughness has not previously been reported.
Multi-scale finite element modeling of 3D printed structures subjected to mechanical loads
Authors: Calneryte Dalia , Barauskas Rimantas , Milasiene Daiva , Maskeliunas Rytis , Neciunas Audrius , Ostreika Armantas , Patasius Martynas , Krisciunas Andrius
Published: November 2017

Purpose

The purpose of this paper is to investigate the influence of geometrical microstructure of items obtained by applying a three-dimensional (3D) printing technology on their mechanical strength.

Design/methodology/approach

Three-dimensional printed items (3DPI) are composite structures of complex internal constitution. The buildup of the finite element (FE) computational models of 3DPI is based on a multi-scale approach. At the micro-scale, the FE models of representative volume elements corresponding to different additive layer heights and different thicknesses of extruded fibers are investigated to obtain the equivalent non-linear nominal stress–strain curves. The obtained results are used for the creation of macro-scale FE models, which enable to simulate the overall structural response of 3D printed samples subjected to tensile and bending loads.

Findings

The validation of the models was performed by comparing the computed results against the experimental ones, where satisfactory agreement has been demonstrated within a marked range of thicknesses of additive layers. Certain inadequacies between computed against experimental results were observed in cases of thinnest and thickest additive layers. The principle explanation of the reasons of inadequacies takes into account the poorer quality of mutual adhesion in case of very thin extruded fibers and too-early solidification effect.

Originality/value

Flexural and tensile experiments are simulated by FE models that are created with consideration to microstructure of 3D printed samples.
Effects of micro particle reinforcement on mechanical properties of 3D printed parts
Authors: Çantı Ebubekir , Aydın Mustafa
Published: November 2017

Purpose

The purpose of this paper is to characterize the effects of different micro particle reinforcement with same weight ratio in acrylonitrile-butadiene-styrene (ABS) feed-stocks for 3D printing process.

Design/methodology/approach

In this study, composite filaments were produced by using a co-rotational twin screw extruder and used as building material to print samples in a commercial fused deposition modeling (FDM) 3D printer. The reinforcement particles, ZrB2 and Al, have different properties, including density, surface area, purity and particle morphology, and were expected to improve mechanical properties of 3D printed samples. Differential calorimetry scanning and melt flow index studies were applied on the materials to observe the change in glass transition temperatures and melt flow behaviors, respectively. Also, to evaluate the mechanical properties, tensile and three-point bending test were carried out. Fractured surfaces were characterized via energy-dispersive X-ray spectroscopy for validation of the reinforcements in the ABS matrix. Moreover, scanning electron microscope micrograph examination was conducted on the fractured surfaces to characterize fracture modes.

Findings

For 3D printed samples, a strain increase of at least 82.5 per cent was achieved by using micro particle reinforcement with a weight ratio of 1.5 per cent.

Research limitations/implications

Higher filler ratios of the reinforcement particles cause loss on the printability of the feed-stocks.

Practical implications

Reinforced ABS stands out as a possible solution to overcome robustness problems in FDM printing.

Originality/value

Even though the effects of printing parameters on the mechanical properties of 3D printed parts have been vastly studied in the literature, studies conducted on improvement of the building materials are limited. This paper proposes to create novel feed-stock materials for achieving printed parts with superior properties using polymer composites.
Effects of titanium dioxide and tartrazine lake on Z-axis resolution and physical properties of resins printed by visible-light 3D printers
Authors: Chang Wei-Ting , Hsu Huang-Jan , Jiang Cho-Pei , Lee Shyh-Yuan , Lin Yuan-Min
Published: November 2017

Purpose

The aim of this paper is to examine the effects of light controlling system that combined high refractive particles (n-TiO2 [titanium dioxide – TiO2]) and tartrazine lake dye (TL dye) on thickness, flexural strength, flexural modulus and surface details of the 3D-printed resin.

Design/methodology/approach

Influences of different concentrations of n-TiO2 and TL dye in light-cured resin formulations for 3D printing (3DP) application were evaluated, including curing thickness, flexural strength and surface details under scanning electron microscopy.

Findings

The polymerization thickness of samples containing both n-TiO2 and TL dye was lower compared to samples with TL dye solely. Samples containing more n-TiO2 and more TL dye exhibited lower flexural strength and modulus. Ramp models showed that for samples containing 1 per cent TL dye, when their n-TiO2 content increased from 1 to 5 per cent, surface laminate structures became sharper. However, when the TL dye content doubled to 2 per cent, the surface laminate structures were indefinite compared to 1 per cent TL dye-containing counterparts.

Originality value

In visible-light 3DP, light controlling system in cooperate dye with high refractive particles provides better energy distribution and scattering control. High refractive particles, dyes and light exposure time had influenced the surface resolution and mechanical properties of the 3DP products.
Curing parameters to improve the mechanical properties of stereolithographic printed specimens
Authors: Watters Matthew P. , Bernhardt Michelle L.
Published: November 2017

Purpose

This paper presents findings from a study examining curing procedures to improve the compressive strength and hardness properties of specimens while maintaining surface quality. All specimens were created from a standard grey, acrylic-based photopolymer and fabricated using stereolithography technology. This paper aims to investigate the effects of printing layer thickness and print orientation on specimen compressive strength, as well as the effects of thermal and light curing methods. In addition, the post-print curing depth was investigated.

Design/methodology/approach

The effects of layer thickness and print orientation were investigated on 10 × 20 mm cylinders by determining the ultimate compressive strength once cured. The compressive strength of cylinders subjected to varying thermal and light settings was also investigated to determine the optimal curing settings. The effective depth of curing was investigated on a 25.4-mm cuboidal specimen, which received both thermal and light curing.

Findings

To achieve the highest compressive strength, specimens shall be printed with the minimal layer thickness of 25 µm. Increasing temperatures up to 60° C during curing provided a 0.75-MPa increase in compressive strength per degree Celsius. However, increasing temperatures above 60° C only provided a 0.15-MPa increase in compressive strength per degree Celsius. Furthermore, curing temperatures above 110° C resulted in degraded surface quality noted by defects at the layer laminations. Specimens required a minimum light curing exposure time of four hours to reach the maximum cure at which point any increase in exposure time provided no substantial increase in compressive strength.

Originality/value

This study provides recommendations for printing parameters and curing methods to achieve the optimum mechanical properties of cured stereolithography specimens.
Highly variable clinical feature and course of aggressive digital papillary adenocarcinoma
Authors: Yokota Kenji , Kono Michihiro , Shimizu Kazue , Sakakibara Akihiro , Akiyama Masashi
Published: November 2017

Aggressive digital papillary adenocarcinoma (ADPA) is a rare cutaneous tumor with sweat gland differentiation. Due to the high risk of local recurrence and delayed metastasis, the wide local resection of the primary lesion and long‐term follow up are recommended for ADPA. Here, we report two cases of ADPA. Case 1 had a blue‐gray nodule on the tip of the right middle finger. Case 2 had had a papule on the dorsal side of the left ring finger for 13 years. In both cases, papillary proliferations of the tumor cells showed multilobular adenomatous structures with back‐to‐back patterns characteristic of ADPA. We amputated the finger at the proximal interphalangeal joint and performed a wide resection of the primary tumor in Case 1 and 2, respectively. Sentinel lymph node biopsy in the axilla was performed, and no sentinel lymph node metastasis was found in either case. Among the previously reported ADPA cases, clinically, most lesions were skin‐colored or tan‐brown to gray. The blue‐gray color in Case 1 is thought to be extraordinary for ADPA. In Case 2, the patient had had the small lesion for more than 13 years and the tumor size had been stable during that long period. The present two cases suggest that ADPA shows a prominent variety of both clinical features and disease courses, and that we cannot exclude the possibility of ADPA even in cases of blue‐gray nodules or small, stable, non‐progressive papules.
Institutional Investment, Asset Illiquidity and Post‐Crash Housing Market Dynamics
Authors: Smith Patrick S. , Liu Crocker H.
Published: November 2017

We examine institutional investors’ entry into the equity side of the single‐family detached housing market using an asset illiquidity framework. We find that institutional investors purchased owner‐occupied houses after the real estate crisis for approximately 6.3–11.8% less than owner‐occupiers. The large discount was in addition to distressed sale and cash purchase discounts which, when combined, highlight the low liquidation value for owner‐occupied housing. The results suggest that asset illiquidity is an important cost of leverage in the owner‐occupied housing market.
Apparent transverse relaxation () on MRI as a method to differentiate treatment effect (pseudoprogression) versus progressive disease in chemoradiation for malignant glioma
Authors: Belliveau Jean‐Guy , Bauman Glenn S , Macdonald David , Macdonald Maria , Klassen L Martyn , Menon Ravi S
Published: November 2017

Introduction

Pseudoprogression (psPD) is a transient post‐treatment imaging change that is commonly seen when treating glioma with chemotherapy and radiation. The use of apparent transverse relaxation rate (), which is calculated from a contrast‐free multi‐echo gradient echo Magnetic Resonance Imaging (MRI) sequence, may allow for quantitative identification of patients with suspected psPD.

Methods

We acquired a multi‐echo gradient echo sequence using a 3T‐Siemens Prisma MRI. The signal decay through the echoes was fitted to provide the coefficient. We segmented the T1‐gadolinium enhancing the image to provide a contrast enhancing lesion (CEL) and the FLAIR hyperintensity to provide a non‐enhancing lesion (NEL). These regions of interest were applied to the multi‐echo gradient echo to acquire a mean within the CEL and NEL. We additionally acquired ADC data to attempt to corroborate our findings.

Results

We found that patients who later exhibited PD exhibited a higher within the CEL as well as a higher ratio of CEL to NEL. Our data correctly distinguished pseudoprogression from treatment effect in 9/9 patients, while ADC corrected identified 7/9 patients using an absolute ADC of 1200 × 10−6 mm2/s.

Conclusions

Our method seems promising for the accurate identification of psPD, and the technique is amenable to evaluation in larger, multi‐centre patient cohorts.
Narrowing filtered QRS duration on signal‐averaged electrocardiogram predicts outcomes in cardiac resynchronization therapy patients with nonischemic heart failure
Authors: Suzuki Atsushi , Shiga Tsuyoshi , Yagishita Daigo , Yagishita‐Tagawa Yoshimi , Arai Kotaro , Iwanami Yuji , Ejima Koichiro , Ashihara Kyomi , Shoda Morio , Hagiwara Nobuhisa
Published: November 2017

Background

To evaluate the impact of changes in the filtered QRS duration (fQRS) on signal‐averaged electrocardiograms (SAECGs) from pre‐ to postimplantation on the clinical outcomes in nonischemic heart failure (HF) patients under cardiac resynchronization therapy (CRT).

Methods

We studied 103 patients with nonischemic HF and sinus rhythm who underwent CRT implantation. SAECGs were obtained within 1 week before and 1 week after implantation and narrowing fQRS was defined as a decrease in fQRS from pre‐ to postimplantation. Echocardiography was performed before and 6 months after CRT implantation. The primary outcome was death from any cause. The secondary outcomes were hospitalization due to worsened HF and occurrence of ventricular tachyarrhythmias.

Results

Of the 103 CRT patients, 53 (51%) showed narrowing fQRS. Left ventricular end‐diastolic volume and end‐systolic volume were significantly reduced (both p < .001), and the left ventricular ejection fraction was significantly increased (p < .001) after CRT in patients with narrowing fQRS, but not in patients with nonnarrowing fQRS. During a median follow‐up period of 33 months, patients with narrowing fQRS exhibited better survival than patients with nonnarrowing fQRS (p = .007). A lower incidence of hospitalization due to worsened HF (p < .001) and a lower occurrence of ventricular tachyarrhythmias (p = .071) were obtained in patients with narrowing fQRS. After adjusting for confounding variables, narrowing fQRS was associated with a low risk of mortality (HR 0.27, p = .006).

Conclusion

Our results suggested that narrowing fQRS on SAECG after CRT implantation predicts LV reverse remodeling and long‐term outcomes in nonischemic HF patients.
Ophthalmic features of cone‐rod dystrophy caused by pathogenic variants in the ALMS1 gene
Authors: Nasser Fadi , Weisschuh Nicole , Maffei Pietro , Milan Gabriella , Heller Corina , Zrenner Eberhart , Kohl Susanne , Kuehlewein Laura
Published: November 2017

Purpose

We aim to describe ophthalmic characteristics and systemic findings in a cohort of seven patients with cone‐rod retinal dystrophy (CORD) caused by pathogenic variants in the ALMS1 gene.

Methods

Seven patients with Alström syndrome (ALMS) were included in the study. A comprehensive ophthalmological examination was performed, including best‐corrected visual acuity (BCVA), a semiautomated kinetic visual field exam, colour vision testing, full‐field electroretinography testing according to International Society for Clinical Electrophysiology of Vision (ISCEV) standards, spectral domain optical coherence tomography (SD‐OCT) and fundus autofluorescence (FAF) imaging, and slit lamp and dilated fundus examination. DNA samples were analysed using Sanger sequencing or exome sequencing.

Results

In our cohort, the ocular phenotype presented with a wide variability in retinal function and disease severity. However, age of symptom onset (i.e. nystagmus and photophobia) was at 6–9 months in all patients. These symptoms mostly mislead to the diagnosis of congenital achromatopsia (ACHM), Leber congenital amaurosis (LCA), isolated CORD or Bardet–Biedl syndrome. The systemic manifestations in our cohort were highly variable.

Conclusion

In summary, we can report that most of our ALMS patients primarily presented with nystagmus and severe photophobia since early childhood interestingly without night blindness in the absence of systemic symptoms. Only genetic testing analysing both nonsyndromic retinal disease (RD) genes and syndromic ciliopathy genes by comprehensive panel sequencing can result in the correct diagnosis, genetically and clinically, with important implication for the physical health of the individual.
Prediction of olanzapine exposure in individual patients using physiologically based pharmacokinetic modelling and simulation
Authors: Polasek Thomas M. , Tucker Geoffrey T. , Sorich Michael J. , Wiese Michael D. , Mohan Titus , Rostami‐Hodjegan Amin , Korprasertthaworn Porntipa , Perera Vidya , Rowland Andrew
Published: November 2017

Aim

The aim of the present study was to predict olanzapine (OLZ) exposure in individual patients using physiologically based pharmacokinetic modelling and simulation (PBPK M&S).

Methods

A ‘bottom‐up’ PBPK model for OLZ was constructed in Simcyp® (V14.1) and validated against pharmacokinetic studies and data from therapeutic drug monitoring (TDM). The physiological, demographic and genetic attributes of the ‘healthy volunteer population’ file in Simcyp® were then individualized to create ‘virtual twins’ of 14 patients. The predicted systemic exposure of OLZ in virtual twins was compared with measured concentration in corresponding patients. Predicted exposures were used to calculate a hypothetical decrease in exposure variability after OLZ dose adjustment.

Results

The pharmacokinetic parameters of OLZ from single‐dose studies were accurately predicted in healthy Caucasians [mean‐fold errors (MFEs) ranged from 0.68 to 1.14], healthy Chinese (MFEs 0.82 to 1.18) and geriatric Caucasians (MFEs 0.55 to 1.30). Cumulative frequency plots of trough OLZ concentration were comparable between the virtual population and patients in a TDM database. After creating virtual twins in Simcyp®, the R2 values for predicted vs. observed trough OLZ concentrations were 0.833 for the full cohort of 14 patients and 0.884 for the 7 patients who had additional cytochrome P450 2C8 genotyping. The variability in OLZ exposure following hypothetical dose adjustment guided by PBPK M&S was twofold lower compared with a fixed‐dose regimen – coefficient of variation values were 0.18 and 0.37, respectively.

Conclusions

Olanzapine exposure in individual patients was predicted using PBPK M&S. Repurposing of available PBPK M&S platforms is an option for model‐informed precision dosing and requires further study to examine clinical potential.
Environmental heterogeneity and biotic interactions mediate climate impacts on tropical forest regeneration
Authors: Uriarte María , Muscarella Robert , Zimmerman Jess K.
Published: November 2017

Predicting the fate of tropical forests under a changing climate requires understanding species responses to climatic variability and extremes. Seedlings may be particularly vulnerable to climatic stress given low stored resources and undeveloped roots; they also portend the potential effects of climate change on future forest composition. Here we use data for ca. 50,000 tropical seedlings representing 25 woody species to assess (i) the effects of interannual variation in rainfall and solar radiation between 2007 and 2016 on seedling survival over 9 years in a subtropical forest; and (ii) how spatial heterogeneity in three environmental factors—soil moisture, understory light, and conspecific neighborhood density—modulate these responses. Community‐wide seedling survival was not sensitive to interannual rainfall variability but interspecific variation in these responses was large, overwhelming the average community response. In contrast, community‐wide responses to solar radiation were predominantly positive. Spatial heterogeneity in soil moisture and conspecific density were the predominant and most consistent drivers of seedling survival, with the majority of species exhibiting greater survival at low conspecific densities and positive or nonlinear responses to soil moisture. This environmental heterogeneity modulated impacts of rainfall and solar radiation. Negative conspecific effects were amplified during rainy years and at dry sites, whereas the positive effects of radiation on survival were more pronounced for seedlings existing at high understory light levels. These results demonstrate that environmental heterogeneity is not only the main driver of seedling survival in this forest but also plays a central role in buffering or exacerbating impacts of climate fluctuations on forest regeneration. Since seedlings represent a key bottleneck in the demographic cycle of trees, efforts to predict the long‐term effects of a changing climate on tropical forests must take into account this environmental heterogeneity and how its effects on regeneration dynamics play out in long‐term stand dynamics.
Using calcium sulfate cement—Hydroxypropyl methyl cellulose/sodium alginate composites as substitutes of bone wax
Authors: Zhou Huan , Yang Mengmeng , Ni Xinye , Yang Lei , Kutty Muralithran G.
Published: November 2017

Development of alternatives of bone wax to stop blood transfusion occurred in cancellous bone injury is highly deserved clinically. An ideal candidate is supposed to be not only biodegradable, biocompatible, malleable, and cost‐effective, but also have comparable mechanical strength to cancellous bone. In the present work, calcium sulfate cement (CSC) based composites modified with hydroxypropyl methyl cellulose (HPMC) or sodium alginate (SA) were prepared. In brief, CSC was combined with 2, 4, 6 wt.% of HPMC or SA, respectively, followed by setting behavior evaluation, compressive strength and degradation testing, XRD, and SEM characterizations, as well as blood clotting induction study. Both additives improved the hemostatic performance of CSC, but CSC with 2% wt. SA exhibited the optimum setting time, mechanical strength, stability, and blood clotting ability. These results reveal the feasibility of using CSC–SA based composite as a substitute for bone wax.