bluuebunny/crossref_metadata_2025 huggingface dataset:
Warhead biosynthesis and the origin of structural diversity in hydroxamate metalloproteinase inhibitors
Authors: Leipoldt Franziska , Santos-Aberturas Javier , Stegmann Dennis P. , Wolf Felix , Kulik Andreas , Lacret Rodney , Popadić Désirée , Keinhörster Daniela , Kirchner Norbert , Bekiesch Paulina , Gross Harald , Truman Andrew W. , Kaysser Leonard
Published: November 2017

Metalloproteinase inhibitors often feature hydroxamate moieties to facilitate the chelation of metal ions in the catalytic center of target enzymes. Actinonin and matlystatins are  potent metalloproteinase inhibitors that comprise rare N-hydroxy-2-pentyl-succinamic acid warheads. Here we report the identification and characterization of their biosynthetic pathways. By gene cluster comparison and a combination of precursor feeding studies, heterologous pathway expression and gene deletion experiments we are able to show that the N-hydroxy-alkyl-succinamic acid warhead is generated by an unprecedented variation of the ethylmalonyl-CoA pathway. Moreover, we present evidence that the remarkable structural diversity of matlystatin congeners originates from the activity of a decarboxylase-dehydrogenase enzyme with high similarity to enzymes that form epoxyketones. We further exploit this mechanism to direct the biosynthesis of non-natural matlystatin derivatives. Our work paves the way for follow-up studies on these fascinating pathways and allows the identification of new protease inhibitors by genome mining.
Reversible silencing of lumbar spinal interneurons unmasks a task-specific network for securing hindlimb alternation
Authors: Pocratsky Amanda M. , Burke Darlene A. , Morehouse Johnny R. , Beare Jason E. , Riegler Amberly S. , Tsoulfas Pantelis , States Gregory J. R. , Whittemore Scott R. , Magnuson David S. K.
Published: November 2017

Neural circuitry in the lumbar spinal cord governs two principal features of locomotion, rhythm and pattern, which reflect intra- and interlimb movement. These features are functionally organized into a hierarchy that precisely controls stepping in a stereotypic, speed-dependent fashion. Here, we show that a specific component of the locomotor pattern can be independently manipulated. Silencing spinal L2 interneurons that project to L5 selectively disrupts hindlimb alternation allowing a continuum of walking to hopping to emerge from the otherwise intact network. This perturbation, which is independent of speed and occurs spontaneously with each step, does not disrupt multi-joint movements or forelimb alternation, nor does it translate to a non-weight-bearing locomotor activity. Both the underlying rhythm and the usual relationship between speed and spatiotemporal characteristics of stepping persist. These data illustrate that hindlimb alternation can be manipulated independently from other core features of stepping, revealing a striking freedom in an otherwise precisely controlled system.
3D microniches reveal the importance of cell size and shape
Authors: Bao Min , Xie Jing , Piruska Aigars , Huck Wilhelm T. S.
Published: November 2017

Geometrical cues have been shown to alter gene expression and differentiation on 2D substrates. However, little is known about how geometrical cues affect cell function in 3D. One major reason for this lack of understanding is rooted in the difficulties of controlling cell geometry in a complex 3D setting and for long periods of culture. Here, we present a robust method to control cell volume and shape of individual human mesenchymal stem cells (hMSCs) inside 3D microniches with a range of different geometries (e.g., cylinder, triangular prism, cubic, and cuboid). We find that the actin filaments, focal adhesions, nuclear shape, YAP/TAZ localization, cell contractility, nuclear accumulation of histone deacetylase 3, and lineage selection are all sensitive to cell volume. Our 3D microniches enable fundamental studies on the impact of biophysical cues on cell fate, and have potential applications in investigating how multicellular architectures organize within geometrically well-defined 3D spaces.
Solution and gas phase evidence of anion binding through the secondary bonding interactions of a bidentate bis-antimony(iii) anion receptor
Authors: Qiu J. , Song B. , Li X. , Cozzolino A. F.
Published: November 2017

Solution and gas phase evidence of halide binding to a bis-antimony(iii) anion receptor is demonstrated through NMR titrations and ESI-MS.
Can electrostatic catalysis of Diels–Alder reactions be harnessed with pH-switchable charged functional groups?
Authors: Aitken Heather M. , Coote Michelle L.
Published: November 2017

Quantum-chemical calculations demonstrate that acid and base groups can be used to pH-switch regio- and diastereoselectivity in Diels–Alder reactions and provide a practical means of harnessing electrostatic catalysis.
ROS-mediated carbon monoxide and drug release from drug-conjugated carboxyboranes
Authors: Ayudhya T. I. , Pellechia P. J. , Dingra N. N.
Published: November 2017

Dual nature of amine carboxyboranes for combined CO and drug delivery is facilitated by ROS.
Three-in-one type fluorescent sensor based on a pyrene pyridoxal cascade for the selective detection of Zn(ii), hydrogen phosphate and cysteine
Authors: Upadhyay Yachana , Anand Thangaraj , Babu Lavanya Thilak , Paira Priyankar , Crisponi Guido , SK Ashok Kumar , Kumar Rajender , Sahoo Suban K.
Published: November 2017

A novel fluorescent receptor L was developed for the selective detection of important bioactive analytes.
Stability of mixed-oxide titanosilicates: dependency on size and composition from nanocluster to bulk
Authors: Cuko Andi , Calatayud Monica , Bromley Stefan T.
Published: November 2017

Nanostructured mixed titanosilicate materials have great potential for applications (e.g.(photo)catalysis) but are susceptible to phase segregation. Here, we follow the structural and energetic evolution of mixed (TixSi1−xO2)nnanosystems with increasing size. Unlike in the bulk, intimate homogeneous TiO2–SiO2mixing is predicted to be energetically favourable in nanoclusters.
Understanding the formation of the metastable ferroelectric phase in hafnia–zirconia solid solution thin films
Authors: Park Min Hyuk , Lee Young Hwan , Kim Han Joon , Kim Yu Jin , Moon Taehwan , Kim Keum Do , Hyun Seung Dam , Mikolajick Thomas , Schroeder Uwe , Hwang Cheol Seong
Published: November 2017

The origin of the formation of the unexpected ferroelectric orthorhombic phase is systematically examined based on both thermodynamics and kinetics.
Contacts to solution-synthesized SnS nanoribbons: dependence of barrier height on metal work function
Authors: Hajzus Jenifer R. , Biacchi Adam J. , Le Son T. , Richter Curt A. , Hight Walker Angela R. , Porter Lisa M.
Published: November 2017

Four different metals were patterned onto individual, solution-synthesized SnS nanoribbons to determine Schottky barrier heights and specific contact resistances.
I2 catalyzed access of spiro[indoline-3,4′-pyridine] appended amine dyad: new ON–OFF chemosensors for Cu2+ and imaging in living cells
Authors: Mondal Animesh , Naskar Barnali , Goswami Sanchita , Prodhan Chandraday , Chaudhuri Keya , Mukhopadhyay Chhanda
Published: November 2017

An efficient, easily tuneable route to construct a structurally diverse organic fluorescent probe and its applications towards the colorimetric detection of Cu2+ ions and in vitro fluorescent cell imaging of Cu2+ in HepG2 cells.
Styrene and substituted styrene grafted functional polyolefinsvianitroxide mediated polymerization
Authors: Domenichelli Ilaria , Banerjee Sanjib , Taddei Sara , Martinelli Elisa , Passaglia Elisa , Ameduri Bruno
Published: November 2017

Functionalized polyolefins bearing alkoxyamines derived from a nitroxide radical coupling reaction were successfully used as macroinitiators to graft polystyrene or substituted polystyrene brushesvianitroxide mediated polymerization.
Morphology control in polymerised high internal phase emulsion templated via macro-RAFT agent composition: visualizing surface chemistry
Authors: Khodabandeh A. , Arrua R. D. , Coad B. R. , Rodemann T. , Ohigashi T. , Kosugi N. , Thickett S. C. , Hilder E. F.
Published: November 2017

A series of polymerized high internal phase emulsion (polyHIPE) materials have been prepared by using a water in oil emulsion stabilized by a macro-RAFT agent, 2-(butylthiocarbonothioylthio)-2-poly(styrene)-b-poly(acrylic acid), acting as a polymeric surfactant.
Emission factor calibration and signal timing optimisation for isolated intersections
Authors: Yao Ronghan , Wang Xiaoyu , Xu Hongfeng , Lian Lian
Published: November 2017

Signal control strategy has a huge effect not only on intersection operations but also on traffic emissions. The basic assumptions are first proposed. Using the second‐by‐second data of vehicular velocity and acceleration, the mathematical expressions are then presented to calibrate the emission factors during green/red on the basis of vehicle‐specific power. Given some necessary constraints, a single‐objective optimisation model and a bi‐objective optimisation model are formulated with the concern of traffic emissions. Considering three levels of traffic demands and two methods of signal timing, the numerical examples are carried out by utilising the VISSIM and MATLAB software packages. The findings indicate that the emission factors during green are explicitly greater than those during red and they are all stable for each pollutant and for each lane group; a scientific signal control system can simultaneously reduce vehicle delay and traffic emissions for isolated intersections.
Electric vehicle‐routing problem with charging demands and energy consumption
Authors: Shao Sai , Guan Wei , Bi Jun
Published: November 2017

An electric vehicle‐routing problem (EVRP) is developed to settle some operation distribution troubles such as battery energy limitations and difficulties in finding charging stations for electric vehicles (EVs). Meanwhile, in view of realistic traffic conditions and features of EVs, energy consumption with travel speed and cargo load is considered in the EVRP model. Moreover, to avoid the depletion of all battery power and ensure safe operation, EVs with insufficient battery power can be recharged at charging stations many times in transit. In conclusion, a large, realistic case study with the road network of Beijing urban, 100 customers and 30 charging stations is conducted to test the performance of the model and obtain an optimal operation scheme consisted of the routes, charging plan and driving paths. The EVRP model is solved based on the hybrid genetic algorithm to get the routes and charging plan. The dynamic Dijkstra algorithm with some improvements over the classical Dijkstra algorithm is applied to find the driving paths called the most energy efficient paths between any two adjacent visited nodes in the routes.
Extensive exploration of comprehensive vehicle attributes using D‐CNN with weighted multi‐attribute strategy
Authors: Yan Zhuo , Feng Youji , Cheng Cheng , Fu Jianting , Zhou Xiangdong , Yuan Jiahu
Published: November 2017

As a classical machine learning method, multi‐task learning (MTL) has been widely applied in computer vision technology. Due to deep convolutional neural network (D‐CNN) having strong ability of feature representation, the combination of MTL and D‐CNN has attracted much attention from researchers recently. However, this kind of combination has rarely been explored in the field of vehicle analysis. The authors propose a D‐CNN enhanced with weighted multi‐attribute strategy for extensive exploration of comprehensive vehicle attributes over surveillance images. Specifically, regarding to recognising vehicle model and make/manufacturer, several related attributes as auxiliary tasks are incorporated in the training process of D‐CNN structure. The proposed strategy focuses more on the main task compared with traditional MTL methods, which has assigned different weights for the main task and auxiliary tasks rather than treating all involved tasks equally. To the extent of their knowledge, this is the first report relating to the combination of D‐CNN and weighted MTL for exploration of comprehensive vehicle attributes. The following experiments will show that the proposed approach outperforms the state‐of‐the‐art method for the vehicle recognition and improves the accuracy rate by about 10% for the analysis of other vehicle attributes on the recently public CompCars dataset.
Short‐term traffic flow prediction using fuzzy information granulation approach under different time intervals
Authors: Guo Jianhua , Liu Zhao , Huang Wei , Wei Yun , Cao Jinde
Published: November 2017

Short‐term traffic flow forecasting has been regarded as essential for intelligent transportation systems, including both point prediction and interval prediction. Compared with point prediction, interval prediction of traffic flow in the future will be critical for traffic managers to make reasonable decisions. This study applies the fuzzy information granulation method to obtain the dispersion range of the collected traffic flow time series, and classical forecasting approaches of K ‐nearest neighbours, back‐propagation neural network, and support vector regression are applied on the dispersion range and the original series itself, constituting a short‐term traffic flow forecasting system with the capability of joint point and interval prediction. Using real‐world traffic flow data collected from a field transportation system in America, the proposed forecasting system is shown to generate workable point prediction and associated prediction interval, demonstrating the validity of the proposed forecasting system. In addition, for unravelling the impact of time interval on the forecasting system, different time intervals are investigated, showing that with the increase in time interval, the stability of the forecasting system increases. Discussions are provided for the proposed approach, and future works are expected to enhance the proposed forecasting system.
Midface Fracture Simulation and Repair: A Computer-Based Algorithm
Authors: Drake Virginia E. , Rizzi Christopher J. , Greywoode Jewel D. , Vakharia Kavita T. , Vakharia Kalpesh T.
Published: November 2017

We introduce a novel computer-based method to digitally fixate midfacial fractures to facilitate more efficient intraoperative fixation. This article aims to describe a novel computer-based algorithm that can be utilized to model midface fracture reduction and fixation and to evaluate the algorithm's ability to produce images similar to true postoperative images. This is a retrospective review combined with cross-sectional survey from January 1, 2010, to December 31, 2015. This study was performed at a single tertiary care, level-I trauma center. Ten patients presenting with acute midfacial traumatic fractures were evaluated. Thirty-five physicians were surveyed regarding the accuracy of the images obtained using the algorithm. A computer algorithm utilizing AquariusNet (TeraRecon, Inc., Foster City, CA) and Adobe Photoshop (Adobe Systems Inc., San Jose, CA) was developed to model midface fracture repair. Preoperative three-dimensional computed tomographic (CT) images were processed using the algorithm. Fractures were virtually reduced and fixated to generate a virtual postoperative image. A survey comparing the virtual postoperative and the actual postoperative images was produced. A Likert-type scale rating system of 0 to 10 (0 being completely different and 10 being identical) was utilized. Survey participants evaluated the similarity of fracture reduction and fixation plate appearance. The algorithm's capacity for future clinical utility was also assessed. Survey response results from 35 physicians were collected and analyzed to determine the accuracy of the algorithm. Ten patients were evaluated. Fracture types included zygomaticomaxillary complex, LeFort, and naso-orbito-ethmoidal complex. Thirty-four images were assessed by a group of 35 physicians from the fields of otolaryngology, oral and maxillofacial surgery, and radiology. Mean response for fracture reduction similarity was 7.8 ± 2.5 and fixation plate similarity was 8.3 ± 1.9. All respondents reported interest in the tool for clinical use. This computer-based algorithm is able to produce virtual images that resemble actual postoperative images. It has the ability to model midface fracture repair and hardware placement.
Contributions of Hamstring Stiffness to Straight-Leg-Raise and Sit-and-Reach Test Scores
Authors: Miyamoto Naokazu , Hirata Kosuke , Kimura Noriko , Miyamoto-Mikami Eri
Published: November 2017

The passive straight-leg-raise (PSLR) and the sit-and-reach (SR) tests have been widely used to assess hamstring extensibility. However, it remains unclear to what extent hamstring stiffness (a measure of material properties) contributes to PSLR and SR test scores. Therefore, we aimed to clarify the relationship between hamstring stiffness and PSLR and SR scores using ultrasound shear wave elastography. Ninety-eight healthy subjects completed the study. Each subject completed PSLR testing, and classic and modified SR testing of the right leg. Muscle shear modulus of the biceps femoris, semitendinosus, and semimembranosus was quantified as an index of muscle stiffness. The relationships between shear modulus of each muscle and PSLR or SR scores were calculated using Pearson’s product-moment correlation coefficients. Shear modulus of the semitendinosus and semimembranosus showed negative correlations with the two PSLR and two SR scores (absolute r value≤0.484). Shear modulus of the biceps femoris was significantly correlated with the PSLR score determined by the examiner and the modified SR score (absolute r value≤0.308). The present findings suggest that PSLR and SR test scores are strongly influenced by factors other than hamstring stiffness and therefore might not accurately evaluate hamstring stiffness.
Social media and political communication
Authors: Karlsson Martin , Åström Joachim
Published: November 2017

As the Internet has come to play a greater role in politics, there has been a
growing scholarly interest in how digital and social media are changing
politics. The competition between the innovation and normalization hypotheses
has been at the center of the debate. This article sets out to identify evidence
of innovation and normalization in terms of how politicians communicate in- and
the level of influence they are attaining within the political blogosphere. The
analyses conducted show paradoxical results as we find that those groups of
politicians who are utilizing political communication in the blogosphere in more
innovative and progressive ways – mirroring the hopes and expectations
about how social media might influence politicians and political
communication – have weaker positions within the blog network compared to
other politicians.
The Effects of Endotracheal Suctioning in the Pediatric Population
Authors: Fisk Anna C.
Published: November 2017

Background:

Critically ill pediatric patients with endotracheal tubes routinely receive endotracheal tube suctioning to clear secretions and ensure tube patency. This common practice can result in adverse effects.

Objectives:

The aim of this study was to evaluate the research literature on the stressors of endotracheal suctioning and consequent effect on the pediatric patient.

Methods:

An integrative review was conducted using the Whittemore and Knafl modified framework for integrative reviews, and article selection was guided by the Preferred Reporting Items for Systematic Reviews and Meta-analyses flow diagram. A literature search was conducted via PubMed, the Cumulative Index to Nursing and Allied Health Literature, and Scopus. Selected articles were evaluated to present the current evidence on the stressors of endotracheal suctioning in the pediatric population.

Results:

This review includes 14 articles, with a total of 849 patients, ranging in age from premature neonates to 17 years of age. The available literature aligned into 3 categories: neurovascular effects, respiratory systems effects, and pain related to endotracheal tube suctioning. Pain was the most prevalent category, with half of the studies using endotracheal suctioning as a painful procedure to validate pain assessment tools rather than examining the effect of suctioning. A majority of the studies (67%) were conducted in the premature neonate population. Children with congenital cardiac or pulmonary defects, genetic syndromes, or neurological injuries were frequently excluded.

Conclusions:

Literature regarding the effects of endotracheal suctioning in children is limited. There are many extrapersonal, interpersonal, and intrapersonal stressors associated with endotracheal suctioning that merit future research.
Hematomas in Tiger Territory
Authors: Teso Desarom , Rogoway Benjamin J. , Vea Yolanda L. , Threlkeld Judson E. , Dulabon George R. , Karmy-Jones Riyad C.
Published: November 2017

A 26-year-old man presented with gunshot wound to the epigastrium. At surgery, he was hemodynamically stable and had a tense hematoma with thrill in zone 2 (right side) and porta triad. After liver injury was controlled, he underwent percutaneous stenting of a renal artery-vena cava fistula and the hepatic artery injury was followed. Historically, penetrating injury to zone 2 has mandated operative exploration. However, with the advent of endovascular options, in stable patients, catheter-based options offer a reasonable alternative with less risk of blood loss and possible nephrectomy. Renal artery stenting has been advocated for renal artery cava fistulas. The role of timing, hybrid operating suites, and traditional operative exposure will vary based on presentation and institutional capabilities.
Impact of an Ultrasonically Activated Device in Robot-Assisted Distal Gastrectomy
Authors: Hikage Makoto , Tokunaga Masanori , Makuuchi Rie , Tanizawa Yutaka , Bando Etsuro , Kawamura Taiichi , Terashima Masanori
Published: November 2017

Objective

Robot-assisted gastrectomy is increasingly used for the treatment of gastric cancer, although it remains a time-consuming procedure. An ultrasonically activated device might be useful to shorten operation times. This study therefore assessed the effect of ultrasonically activated device use on procedural times and on other early surgical outcomes.

Methods

Consecutive patients (N = 42) who underwent robot-assisted distal gastrectomy for gastric cancer were included. Clinicopathological characteristics and early surgical outcomes were compared between robotic-assisted gastrectomy procedures using an ultrasonically activated device (U group, n = 21) and those without it (NU group, n = 21).

Results

There were no significant differences in patient characteristics between the groups; however, the median operation time was significantly less in the U group than in the NU group (291 vs 351 minutes, P = 0.006). In detail, the median duration of console time until dividing the duodenum was less in the U group (70 vs 102 minutes, P < 0.001). Estimated blood loss, incidence of postoperative morbidity, and duration of postoperative hospital stay were not different between the groups.

Conclusions

An ultrasonically activated device reduced the operation time of robot-assisted gastrectomy without increasing blood loss and morbidity.
Success Rate of Tympanic Membrane Closure in the Elderly Compared to Younger Adults
Authors: Jolink Casper , Zwemstra Max R. , de Wolf Maarten J. F. , Ebbens Fenna A. , van Spronsen Erik
Published: November 2017

Objective:

To assess the effectiveness and safety of tympanoplasty in elderly patients and the effect of frailty on the results.

Study Design:

Retrospective chart review.

Setting:

Tertiary referral center.

Patients:

Thirty-one ears in 30 patients aged 65 years and older were included and matched with 31 controls, based on the type of surgery, of a pool of 133 patients aged 35 to 55 years.

Intervention:

Therapeutic.

Main Outcome Measure:

Success was defined as tympanic membrane closure and resolution of presenting complaints. Complications were assessed. Frailty was defined by assessing multimorbidity and polypharmacy. Fisher's exact test was used to compare success and complication rates between the age groups. Linear logistic regression analysis using generalized linear models was performed on success and complication rate.

Results:

Success rates in both the groups were 84%. Complication rate in the elderly group was 16% versus 6% in the control group. This difference was not statistically significant in the Fisher's exact test. In the generalized linear model analysis age group, multimorbidity and polypharmacy had no significant influence on both success and complication rate.

Conclusion:

There was no difference in success and complication rate in elderly undergoing tympanoplasty compared with younger adults. Having multimorbidity or polypharmacy did not correlate with failure of the tympanic membrane closure or a higher complication rate.
A new sequence logo plot to highlight enrichment and depletion
Authors: Dey Kushal K. , Xie Dongyue , Stephens Matthew
Published: November 2017

Background

Sequence logo plots have become a standard graphical tool for visualizing sequence motifs in DNA, RNA or protein sequences. However standard logo plots primarily highlight enrichment of symbols, and may fail to highlight interesting depletions. Current alternatives that try to highlight depletion often produce visually cluttered logos.

Results

We introduce a new sequence logo plot, the EDLogo plot, that highlights both enrichment and depletion, while minimizing visual clutter. We provide an easy-to-use and highly customizable R package Logolas to produce a range of logo plots, including EDLogo plots. This software also allows elements in the logo plot to be strings of characters, rather than a single character, extending the range of applications beyond the usual DNA, RNA or protein sequences. We illustrate our methods and software on applications to transcription factor binding site motifs, protein sequence alignments and cancer mutation signature profiles.

Conclusion

Our new EDLogo plots, and flexible software implementation, can help data analysts visualize both enrichment and depletion of characters (DNA sequence bases, amino acids, etc) across a wide range of applications.
Enumerating all possible biosynthetic pathways from metabolic networks
Authors: Ravikrishnan Aarthi , Nasre Meghana , Raman Karthik
Published: November 2017

Exhaustive identification of all alternate possible pathways that exist within metabolic networks can provide valuable insights into cellular metabolism. With the growing number of metabolic reconstructions, there is a need for an efficient method to enumerate pathways, which can also scale well to large metabolic networks, such as those corresponding to microbial communities.

We developed MetQuest, an efficient graph-theoretic algorithm to enumerate all possible pathways of a particular length between a given set of source and target molecules. Our algorithm employs aguidedbreadth-first search to identify all feasible reactions based on the availability of the precursor molecules, followed by a novel dynamic-programming based enumeration, which assembles these reactions into pathways producing the target from the source. We demonstrate several interesting applications of our algorithm, ranging from predicting amino acid biosynthesis pathways to identifying the most diverse pathways involved in degradation of complex molecules. We also illustrate the scalability of our algorithm, by studying larger graphs such as those corresponding to microbial communities, and identify several metabolic interactions happening therein.

A Python-based implementation of MetQuest is available athttps://github.com/RamanLab/MetQuest
Conformational control of translation termination on the 70S ribosome
Authors: Svidritskiy Egor , Korostelev Andrei A.
Published: November 2017

Translation termination ensures proper lengths of cellular proteins. During termination, release factor (RF) recognizes a stop codon and catalyzes peptide release. Conformational changes in RF are thought to underlie accurate translation termination. If true, the release factor should bind the A-site codon in inactive (compact) conformation(s), but structural studies of ribosome termination complexes have only captured RFs in an extended, active conformation. Here, we identify a hyper-accurate RF1 variant, and present crystal structures of 70S termination complexes that suggest a structural pathway for RF1 activation. In the presence of blasticidin S, the catalytic domain of RF1 is removed from the peptidyl-transferase center, whereas the codon-recognition domain is fully engaged in stop-codon recognition in the decoding center. RF1 codon recognition induces decoding-center rearrangements that precede accommodation of the catalytic domain. Our findings suggest how structural dynamics of RF1 and the ribosome coordinate stop-codon recognition with peptide release, ensuring accurate translation termination.
Searching for a collective ethos in interorganizational relationships
Authors: Dudley Larkin
Published: November 2017

Globalization accelerates the need to accommodate the ethical guidelines of different cultures, the subject of many of the papers in the symposium. In a similar manner, the increased use of interorganizational relationships to accomplish projects accelerates the need to confront the value discontinuities in collaboration among representatives from the public, private, nonprofit, and volunteer sectors within American society. Rather than tackling the question of the precise principles to follow in models of interorganizational relationships versus the need for the thick descriptions of the particular, the focus of this paper is more middle-range. The paper outlines some suggested means of connecting the assumptions of several models of interorganizational relationships with the insights of models of establishing a collective ethos. The tone is meant to be tentative and suggestive of a way to begin connecting diverse strands of literature, the problematic posed by the increasing engagement of interorganizational relationships in public administration
To integrate or not to integrate? Understanding B2B social media communications
Authors: Gruner Richard L. , Power Damien
Published: November 2017

Purpose

Social media communications on platforms such as Facebook and LinkedIn can allow managers to interact cost effectively with trading partners. However, although most firms have an online presence on multiple social media platforms, the question remains as to whether marketers’ widespread social media investments are beneficial for firms. The paper aims to discuss this issue.

Design/methodology/approach

This paper presents competing hypotheses to explore how firms’ investment in one form of social media impacts activity on another form of social media. To do so, the authors draw on a data set of 208 large Australian organizations using objective social media activity metrics that measure business-to-business (B2B) audience engagement.

Findings

The findings suggest that widespread social media activity on LinkedIn, Twitter, and YouTube negatively affects a firm’s marketing activity on Facebook. The results indicate that having a social media preference whereby firms focus on a specific social media platform is more effective in forming successful inter-organizational relationships than a multiplatform approach.

Originality/value

The study contributes to the sparse research that seeks to leverage social media for audience engagement beyond a business-to-consumer context. The study’s findings provide insights into the key mechanisms that underlie firms’ B2B social media strategies, and in so doing, offer a fresh perspective on the importance of interactive marketing communication.
Representing Metro Manila on Wikipedia
Authors: Luyt Brendan
Published: November 2017

Purpose

The advent and wide use of new digital technologies suggests that the internet is becoming a powerful new media for the imagination of city space. If this is the case then issues concerning urban representation on social media platforms such as Wikipedia provide an area of overlap and interest between urban studies and information studies. The purpose of this paper is to examine the representation of Manila, Philippines, one of the world’s major mega cities, on the popular online encyclopedia Wikipedia.

Design/methodology/approach

The author’s broad approach to the study of Wikipedia is qualitative in nature. For this study the entire Metro Manila article was downloaded on March 16, 2015 and subjected to textual analysis.

Findings

While the Wikipedia article on Manila cannot be classified as promotional, it is clear that much of the city remains invisible in this work. Such a puzzle becomes understandable when we examine the urban studies literature where we find that the spatial logic of the city itself helps conceal much from view, so that what we read on Wikipedia is a view from the islands of privilege rather than the oceans of marginalization that make up much of the city’s spatial form. If such a spatial structure is to change, representations such as found on Wikipedia need to be challenged.

Originality/value

Wikipedia is a key element of today’s information infrastructure yet despite its importance it remains relatively understudied within the field of information science. More specifically, the role of Wikipedia in representing cities, the dominant settlement form in the world today, has not been previously studied.
Fabrication and assessment of mechanical properties of open cell porous regular interconnected metallic structure through rapid manufacturing route
Authors: Singh Jatender Pal , Pandey Pulak Mohan
Published: November 2017

Purpose

The requirements of open cell porous regular interconnected metallic structure (OCPRIMS) in applications such as heat exchangers, sound absorption, fluid flow control, spark arresters and biocompatible inserts have been increased. As per available technology in the present scenario, only the metallic-based rapid prototyping (RP) machines can guarantee fabrication of OCPRIMS. Metal-based RP machines are capital-intensive. So, this study aims to develop a technique for fabrication of OCPRIMS economically using three-dimensional printing (3 DP) and pressureless sintering.

Design/methodology/approach

Three computer-aided design (CAD) models of varying designed interconnected porosity 73, 70 and 60 per cent were modeled to target metallic porosity 27, 30 and 40 per cent. The same were fabricated with ceramic-based powder using 3 DP. Thereafter, spherical bronze powder with average size of 200 µm was filled and sintered in pressureless manner under inert atmosphere of argon. After sintering, the specimens were cleaned with the help of pricking needles and high-pressure water. It flushed the burnt ceramic powder and allowed metallic portion to remain intact. The obtained specimens were inverse of CAD/3 DP models. The dimensional measurement at different stages of fabrication was carried out to find shrinkage. Sintered density and interconnected porosity were measured using Archimedes’ principle. The characterization of the fabricated specimens was done with the help of microstructure analysis, scanning electron microscopy and energy dispersive x-ray analysis. Mechanical properties were assessed using compressive, tensile and Charpy tests.

Findings

The feasibility has been explored successfully to fabricate OCPRIMS of phosphor bronze using 3 DP and pressureless sintering process. Interconnected porosity of 51.45, 56.45, 64.09 per cent of final metallic specimens has been observed against the targeted 27, 30 and 40 per cent. The increase in pore dimensions up to 19.13 per cent and shrinkage up to 5.44 per cent of outer dimensions were found to be the main causes of increase in interconnected porosity level. The characterization results exhibit the behavior of pressureless sintering process and stability of the fabricated specimens. Mechanical properties of fabricated structures are found to be dependent on porosity and strut diameter. Compressive and tensile strength decrease with the increase in porosity for strut diameter less than 1 mm, whereas they increase with the increase in strut diameter of 1 mm or more. A similar trend has been observed for impact strength also.

Originality/value

This paper explores the feasibility to fabricate OCPRIMS economically using 3 DP and pressureless sintering process.
Thermal and surface characterization of ABS replicas made by FDM for rapid tooling applications
Authors: Chohan Jasgurpreet Singh , Singh Rupinder , Boparai Kamaljit Singh
Published: November 2017

Purpose

This paper aims to focus on the changes in thermal and surface characteristics of acrylonitrile butadiene styrene (ABS) material when exposed to chemical vapours for surface finishing. The poor surface finish and the dimensional accuracy of the fused deposition modelling parts (of ABS material) because of the stair-stepping hinder their use for rapid tooling applications, which can be improved by vapour finishing process. The differential scanning calorimetry (DSC) tests are performed to investigate the thermal behaviour of ABS thermoplastic after vapour finishing.

Design/methodology/approach

The hip prosthesis replica has been used to highlight the efficacy of chemical finishing process for intricate and complex geometries. The replicas are treated with chemical vapours for different durations. The DSC tests are performed along with surface roughness, surface hardness and dimensional measurements of exposed replicas and compared with unexposed replica.

Findings

The longer finishing time, i.e. 20 s, manifested higher melting peak temperature, higher melting enthalpy and higher heat capacity along with smoother and harder surface as compared with unexposed replica. The finishing process enhanced the bonding strength and the heat-bearing capacity of ABS material. The vapour finishing process enhanced the thermal stability of the material which may extend its sustainability at higher temperatures.

Practical implications

The improved thermal stability of ABS thermoplastic after chemical vapour finishing has been demonstrated. This advancement allows the use of ABS in functional tooling suitable for small production runs with higher flexibility and lead time savings.

Originality/value

The heat effects associated with phase transitions as a function of temperature are studied in case of replicas finished with chemical vapours. The relationship between melting enthalpy and surface characteristics has been ascertained.
Selective laser melting using holographic beam manipulation: influence of polypropylene molecular weight
Authors: Haworth Barry , Tyrer John R. , Zhou Zhou
Published: November 2017

Purpose

There is a requirement to match selective laser melting (SLM) technologies to a wider range of polymeric materials, as the existing market for SLM powders is dominated by polyamide PA12. Drivers include the tailoring of physical properties to individual applications or cost reduction. Polypropylene (PP) currently has limited use in SLM; so, this paper aims to explore the potential use of PP materials of varying molecular weight (Mw).

Design/methodology/approach

PP polymers of differing Mw were characterised using a range of analytical techniques, including differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), rotational rheometry and real-time hot-stage (optical) microscopy.

Findings

The techniques are sufficiently sensitive to distinguish Mw effects, notably in terms of material viscosity. The stable sintering region for SLM has been defined clearly. Some success was achieved in melting parts using all grades of PP, including higher Mw grades, which potentially offer improved mechanical performance.

Research limitations/implications

The range of techniques (DSC, oxidative induction time and TGA) form an effective analytical package with which to consider new polymeric materials for SLM.

Practical implications

High-Mw PP polymers, in tape or powder form, have potential use in SLM processes, providing scope to enhance part properties in future.

Originality/value

This is believed to be the first in-depth study noting the influence of PP Mw on important physical performance in a proprietary SLM process, using holographic beam manipulation.
Additive manufacturing of ZrO2ceramic dental bridges by stereolithography
Authors: Lian Qin , Sui Wenquan , Wu Xiangquan , Yang Fei , Yang Shaopeng
Published: November 2017

Purpose

This paper aims to develop an additive manufacturing technique for complex zirconia ceramic dental bridges.

Design/methodology/approach

To carry out this study, a dental bridge model was obtained by three-dimensional reverse engineering, and a light-curable zirconia ceramic suspension was formulated. Zirconia bridges were manufactured by stereolithography and then treated by vacuum freeze drying, vacuum infiltration and sintering. The optimal scanning speed was determined according to the shape precision comparison. Then, characteristics of the sintered ceramic parts were tested as size shrinkage, relative density, surface Vickers hardness, surface roughness and microstructure.

Findings

The method for preparation of light-curable zirconia suspension (40 volume per cent solid loading) with a viscosity value of 127 mPa·s was proposed. The optimal laser scanning speed for zirconia bridge fabrication was 1200 mm/s. A relative density of 98.58 per cent was achieved; the obtained surface Vickers hardness and surface roughness were 1,398 HV and 2.06 µm, respectively.

Originality/value

This paper provides a potential technical method for manufacturing complex zirconia dental bridges and other small complex-shaped ceramic components which are difficult to be made by other manufacturing techniques.
Clinical and ex vivo laboratory comparison of the self‐sealing properties and dimensional stability between the femtosecond laser and manual clear corneal incisions
Authors: Kojima Takashi , Takagi Mari , Ichikawa Kei , Horai Rie , Sakai Yukihiro , Tanaka Yoshiki , Tamaoki Akeno , Ichikawa Kazuo
Published: November 2017

Purpose

To compare the self‐sealing features and dimensional stability between the femtosecond laser (FL) and manual knife corneal incision.

Methods

For the clinical study, 29 consecutive eyes from 29 patients and 28 eyes from 28 patients who underwent cataract surgery with FL corneal incision and manual knife incision, respectively, were enrolled. Immediately after cataract surgery, the self‐sealing features of the corneal incisions were evaluated. Scanning electron microscopy (SEM) images were obtained. For the experimental study, clear corneal incisions with a knife or FL with different energy settings (3, 6 and 9 μJ) were created in fresh porcine eyes, followed by a stress test. The incision width was measured before and after the stress test.

Results

In the clinical study, the knife group had a higher self‐sealing score (0.60 ± 0.49 points) than the FL group (0.17 ± 0.38 points). In the experimental study, the deformation rate in the knife incision (5.04 ± 1.93) was significantly lower than that in the FL with any energy. The deformation rate in the 9 μJ (12.98 ± 2.76) was significantly higher than in the 3 μJ (8.54 ± 2.38) and 6 μJ (8.82 ± 2.85) FL energies. Scanning electron microscopy (SEM) images revealed that the corneal stromal surface of the knife incision was smoother than that of the FL. Higher energy FL showed more irregular surfaces.

Conclusion

Higher FL energy tended to widen a clear corneal incision when mechanical stress was applied. The histological differences at the inner tunnel surface may cause differences in wound stability of the corneal incision.
Cyclic analogues of α‐conotoxin Vc1.1 inhibit colonic nociceptors and provide analgesia in a mouse model of chronic abdominal pain
Authors: Castro Joel , Grundy Luke , Deiteren Annemie , Harrington Andrea M , O'Donnell Tracey , Maddern Jessica , Moore Jessi , Garcia‐Caraballo Sonia , Rychkov Grigori Y , Yu Rilei , Kaas Quentin , Craik David J , Adams David J , Brierley Stuart M
Published: November 2017

Background and Purpose

Patients with irritable bowel syndrome suffer from chronic visceral pain (CVP) and limited analgesic therapeutic options are currently available. We have shown that α‐conotoxin Vc1.1 induced activation of GABAB receptors on the peripheral endings of colonic afferents and reduced nociceptive signalling from the viscera. However, the analgesic efficacy of more stable, cyclized versions of Vc1.1 on CVP remains to be determined.

Experimental Approach

Using ex vivo colonic afferent preparations from mice, we determined the inhibitory actions of cyclized Vc1.1 (cVc1.1) and two cVc1.1 analogues on mouse colonic nociceptors in healthy and chronic visceral hypersensitivity (CVH) states. Using whole‐cell patch clamp recordings, we also assessed the inhibitory actions of these peptides on the neuronal excitability of colonic innervating dorsal root ganglion neurons. In vivo, the analgesic efficacy of these analogues was assessed by determining the visceromotor response to colorectal distension in healthy and CVH mice.

Key Results

cVc1.1 and the cVc1.1 analogues, [C2H,C8F]cVc1.1 and [N9W]cVc1.1, all caused concentration‐dependent inhibition of colonic nociceptors from healthy mice. Inhibition by these peptides was greater than those evoked by linear Vc1.1 and was substantially greater in colonic nociceptors from CVH mice. cVc1.1 also reduced excitability of colonic dorsal root ganglion neurons, with greater effect in CVH neurons. CVH mice treated with cVc1.1 intra‐colonically displayed reduced pain responses to noxious colorectal distension compared with vehicle‐treated CVH mice.

Conclusions and Implications

Cyclic versions of Vc1.1 evoked significant anti‐nociceptive actions in CVH states, suggesting that they could be novel candidates for treatment of CVP.

Linked Articles

This article is part of a themed section on Recent Advances in Targeting Ion Channels to Treat Chronic Pain. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.12/issuetoc
Role of anterior segment optical coherence tomography in angle‐closure disease: a review
Authors: Porporato Natalia , Baskaran Mani , Aung Tin
Published: November 2017

This article aims to review the published literature pertaining to the use of anterior segment optical coherence tomography (AS‐OCT) in the evaluation of angle‐closure disease. Searches on the available published literature were last conducted on 15 June 2017. Rated as Level I evidence, we found that AS‐OCT has shown good sensitivity and moderate diagnostic accuracy to detect narrow angles when compared with gonioscopy. AS‐OCT quantitative and qualitative parameters demonstrated strong association with the presence of gonioscopically closed angles. This technology provides an objective non‐contact method of assessing the angle that is well tolerated by the patient and correlates well with the information provided by gonioscopy.
Italy in the Renaissance: a leading economy in the European context, 1350–1550
Authors: Malanima Paolo
Published: November 2017

A well‐known debate on the Renaissance economy was held in this journal in 1962–4 between Roberto S. Lopez and Harry Miskimin on one hand and Carlo M. Cipolla on the other. More than half a century later, this topic can be reconsidered in the light of much wider information on the late medieval/early modern Italian economy. Using data on population, urbanization, prices, wages, and GDP, this article outlines the macroeconomic trends in central and northern Italy in the age of the Renaissance (1350–1550). The frequent plagues during the early Renaissance—that is, between 1348 and 1450—decimated the population, probably causing more deaths than in other European countries. Hence resources per worker increased and labour productivity, incomes, and standards of living improved remarkably. A favourable economic environment thus seems to have been a pre‐condition for the Renaissance in culture, art, and politics and the spread of new kinds of consumer demand. From the middle of the fifteenth century, living standards gradually worsened and eventually reached the low levels that had prevailed prior to the Renaissance.