bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative Perfusion Analysis of the Rectum Using Golden-Angle Radial Sparse Parallel Magnetic Resonance Imaging
Authors: Attenberger Ulrike I. , Liu Jing , Riffel Philipp , Budjan Johannes , Grimm Robert , Block Kai T. , Schoenberg Stefan O. , Wang Xiaoying , Hausmann Daniel
Published: June 2017

Objectives

Purpose of this study was to compare the quality of perfusion maps obtained from prototypical free-breathing magnetic resonance imaging (MRI) with continuous golden-angle radial sampling and iterative reconstruction (GRASP) to conventional acquisition using time-resolved angiography with interleaved stochastic trajectories (TWIST) in patients with rectal cancer.

Material and Methods

Forty cases were included for retrospective analysis. Twenty of the patients received routine multiparametric MRI at 3 T for rectal cancer staging, including perfusion measurement with GRASP or TWIST (10 patients for each technique, including 5 prechemoradiation and 5 postchemoradiation). Twenty patients without history of rectal disease served as control group (10 GRASP, 10 TWIST). GRASP images were reconstructed at temporal resolution of 3.45 seconds (21 spokes/frame). A voxel-by-voxel deconvolution approach was used to determine rectal plasma flow (mL/100 mL per minute). Regions of interest were placed at 3 levels within the tumor and normal rectum (lower, middle, and upper part). The quality of morphologic images, perfusion maps, and arterial input function were scored by 2 blinded radiologists. Independent t tests were applied.

Results

Three patients of the TWIST control group had to be excluded due to technical failure of the sequence. Significantly higher scores for the perfusion maps and arterial input functions (total cohort) were obtained using GRASP (P < 0.05). Artifacts in the perfusion maps were rated significantly lower than for TWIST (P < 0.05). In the healthy rectum cohort, the average plasma flow of normal rectal wall was 31.78 ± 7.39 mL/100 mL per minute with GRASP, compared with 77.62 ± 34.08 mL/100 mL per minute with TWIST, indicating much lower variance for GRASP. Plasma flow values obtained with both methods enabled distinguishing between normal rectal wall and rectal cancer, both before and after chemoradiation. Morphologic image quality was generally higher with GRASP (P < 0.01).

Conclusions

GRASP perfusion imaging can distinguish between normal rectum and rectal cancers with higher image quality and less variance than TWIST. Additional morphologic assessment with high spatial resolution from the GRASP acquisition may increase the accuracy and diagnostic confidence of the examination.
Duloxetine Plasma Concentrations and Its Effectiveness in the Treatment of Nonorganic Chronic Pain in the Orofacial Region
Authors: Kobayashi Yuka , Nagashima Wataru , Tokura Tatsuya , Yoshida Keizo , Umemura Eri , Miyauchi Tomoya , Arao Munetaka , Ito Mikiko , Kimura Hiroyuki , Kurita Kenichi , Ozaki Norio
Published: June 2017

Objective

The purpose of this study was to examine the relationship between the pain-relieving effects of duloxetine and its plasma concentrations in patients with burning mouth syndrome and atypical odontalgia characterized by chronic nonorganic pain in the orofacial region.

Methods

We administered duloxetine to 77 patients diagnosed as having burning mouth syndrome or atypical odontalgia for 12 weeks. The initial dose of duloxetine was established as 20 mg/d and was increased to 40 mg/d after week 2. We evaluated pain using the visual analog scale and depressive symptoms using the Structured Interview Guide for the Hamilton Depression Rating Scale at weeks 0, 2, 4, 6, 8, 10, and 12 and measured plasma concentrations of duloxetine 12 weeks after the start of its administration.

Results

Visual analog scale scores were significantly lower 12 weeks after than at the start of the administration of duloxetine (paired t test, t = 6.65, P < 0.0001). We examined the relationship between the rate of decreases in visual analog scale scores and plasma concentrations of duloxetine. There was no significant linear regression or quadratic regression.

Conclusions

Duloxetine significantly relieved pain in patients with chronic nonorganic pain in the orofacial region. However, no relationship was observed between its pain-relieving effects and plasma concentrations.
Curvature driven motion of a bubble in a toroidal Hele-Shaw cell
Authors: Mughal A. , Cox S. J. , Schröder-Turk G. E.
Published: June 2017

We investigate the equilibrium properties of a single area-minimizing bubble trapped between two narrowly separated parallel curved plates. We begin with the case of a bubble trapped between concentric spherical plates. We develop a model which shows that the surface energy of the bubble is lower when confined between spherical plates than between flat plates. We confirm our findings by comparing against Surface Evolver simulations. We then derive a simple model for a bubble between arbitrarily curved parallel plates. The energy is found to be higher when the local Gaussian curvature of the plates is negative and lower when the curvature is positive. To check the validity of the model, we consider a bubble trapped between concentric tori. In the toroidal case, we find that the sensitivity of the bubble's energy to the local curvature acts as a geometric potential capable of driving bubbles from regions with negative to positive curvature.
Evaluation of radical scavenging system in amoeba
Chaos carolinense
during nutrient deprivation
Authors: Deng Yuru , Lee Edlyn Li-Hui , Chong Ketpin , Almsherqi Zakaria A.
Published: June 2017

The frequent appearance of non-lamellar membrane arrangements such as cubic membranes (CMs) in cells under stressed or pathological conditions points to an intrinsic cellular response mechanism. CM represents highly curved, three-dimensional nano-periodic structures that correspond to mathematically well-defined triply periodic minimal surfaces. Specifically, cellular membrane may transform into CM organization in response to pathological, inflammatory and oxidative stress conditions. CM organization, thus, may provide an advantage to cope with various types of stress. The identification of inducible membrane systems, such as in the mitochondrial inner membranes to cubic morphology upon starvation, opens new avenues for understanding the molecular mechanisms of cellular responses to oxidative stress. In this study, we compared the cellular responses of starved and fed amoeba
Chaos carolinense
to oxidative stress. Food deprivation from
C. carolinense
induces a significant increase in prooxidants such as superoxide and hydrogen peroxide. Surprisingly, we observed a significant lower rate of biomolecular damage in starved cells (with higher free radicals generation) when compared with fed cells. Specifically, lipid and RNA damages were significantly less in starved cells compared with fed cells. This observation was not due to the upregulation of intracellular antioxidants, as starved amoeba show reduced antioxidant enzymatic activities; however, it could be attributed to CM formation. CM could uptake and retain short segments of nucleic acids (resembles cellular RNA)
in vivo
and
in vitro.
Previous results showed that nucleic acids retained within CM sustain a minimal oxidative damage
in vitro
upon exposure to high level of superoxide. We thus propose that CM may act as a ‘protective’ shelter to minimize the oxidation of biologically essential macromolecules such as RNA. In summary, we examined enzymatic antioxidant activities as well as oxidative damage biomarkers in starved amoeba
C. carolinense
in correlation with the potential role of CM as an optimal intracellular membrane organization for the protection of biological macromolecules against oxidative damage.
Competition brings out the best: modelling the frustration between curvature energy and chain stretching energy of lyotropic liquid crystals in bicontinuous cubic phases
Authors: Chen Hao , Jin Chenyu
Published: June 2017

It is commonly considered that the frustration between the curvature energy and the chain stretching energy plays an important role in the formation of lyotropic liquid crystals in bicontinuous cubic phases. Theoretic and numeric calculations were performed for two extreme cases: parallel surfaces eliminate the variance of the chain length; constant mean curvature surfaces eliminate the variance of the mean curvature. We have implemented a model with Brakke's Surface Evolver which allows a competition between the two variances. The result shows a compromise of the two limiting geometries. With data from real systems, we are able to recover the gyroid–diamond–primitive phase sequence which was observed in experiments.
Universal structure motifs in biominerals: a lesson from nature for the efficient design of bioinspired functional materials
Authors: Harris Joe , Böhm Corinna F. , Wolf Stephan E.
Published: June 2017

Biominerals are typically indispensable structures for their host organism in which they serve varying functions, such as mechanical support and protection, mineral storage, detoxification site, or as a sensor or optical guide. In this perspective article, we highlight the occurrence of both structural diversity and uniformity within these biogenic ceramics. For the first time, we demonstrate that the universality–diversity paradigm, which was initially introduced for proteins by Buehleret al. (Cranford & Buehler 2012Biomateriomics; Cranfordet al.2013Adv. Mater.25, 802–824 (doi:10.1002/adma.201202553); Ackbarow & Buehler 2008J. Comput. Theor. Nanosci.5, 1193–1204 (doi:10.1166/jctn.2008.001); Buehler & Yung 2009Nat. Mater.8, 175–188 (doi:10.1038/nmat2387)), is also valid in the realm of biomineralization. A nanogranular composite structure is shared by most biominerals which rests on a common, non-classical crystal growth mechanism. The nanogranular composite structure affects various properties of the macroscale biogenic ceramic, a phenomenon we attribute to emergence. Emergence, in turn, is typical for hierarchically organized materials. This is a clear call to renew comparative studies of even distantly related biomineralizing organisms to identify further universal design motifs and their associated emergent properties. Such universal motifs with emergent macro-scale properties may represent an unparalleled toolbox for the efficient design of bioinspired functional materials.
BslA-stabilized emulsion droplets with designed microstructure
Authors: Bromley Keith M. , MacPhee Cait E.
Published: June 2017

Emulsions are a central component of many modern formulations in food, pharmaceuticals, agrichemicals and personal care products. The droplets in these formulations are limited to being spherical as a consequence of the interfacial tension between the dispersed phase and continuous phase. The ability to control emulsion droplet morphology and stabilize non-spherical droplets would enable the modification of emulsion properties such as stability, substrate binding, delivery rate and rheology. One way of controlling droplet microstructure is to apply an elastic film around the droplet to prevent it from relaxing into a sphere. We have previously shown that BslA, an interfacial protein produced by the bacterial genusBacillus, forms an elastic film when exposed to an oil- or air–water interface. Here, we highlight BslA's ability to stabilize anisotropic emulsion droplets. First, we show that BslA is capable of arresting dynamic emulsification processes leading to emulsions with variable morphologies depending on the conditions and emulsification technique applied. We then show that frozen emulsion droplets can be manipulated to induce partial coalescence. The structure of the partially coalesced droplets is retained after melting, but only when there is sufficient free BslA in the continuous phase. That the fidelity of replication can be tuned by adjusting the amount of free BslA in solution suggests that freezing BslA-stabilized droplets disrupts the BslA film. Finally, we use BslA's ability to preserve emulsion droplet structural integrity throughout the melting process to design emulsion droplets with a chosen shape and size.
How geometric frustration shapes twisted fibres, inside and out: competing morphologies of chiral filament assembly
Authors: Hall Douglas M. , Grason Gregory M.
Published: June 2017

Chirality frustrates and shapes the assembly of flexible filaments in rope-like, twisted bundles and fibres by introducing gradients of both filament shape (i.e. curvature) and packing throughout the structure. Previous models of chiral filament bundle formation have shown that this frustration gives rise to several distinct morphological responses, including self-limiting bundle widths, anisotropic domain (tape-like) formation and topological defects in the lateral inter-filament order. In this paper, we employ a combination of continuum elasticity theory and discrete filament bundle simulations to explore how these distinct morphological responses compete in the broader phase diagram of chiral filament assembly. We show that the most generic model of bundle formation exhibits at least four classes of equilibrium structure—finite-width, twisted bundles with isotropic and anisotropic shapes, with and without topological defects, as well as bulk phases of untwisted, columnar assembly (i.e. ‘frustration escape’). These competing equilibrium morphologies are selected by only a relatively small number of parameters describing filament assembly: bundle surface energy, preferred chiral twist and stiffness of chiral filament interactions, and mechanical stiffness of filaments and their lateral interactions. Discrete filament bundle simulations test and verify continuum theory predictions for dependence of bundle structure (shape, size and packing defects of two-dimensional cross section) on these key parameters.
Molecular interactions of amyloid nanofibrils with biological aggregation modifiers: implications for cytotoxicity mechanisms and biomaterial design
Authors: Dharmadana Durga , Reynolds Nicholas P. , Conn Charlotte E. , Valéry Céline
Published: June 2017

Amyloid nanofibrils are ubiquitous biological protein fibrous aggregates, with a wide range of either toxic or beneficial activities that are relevant to human disease and normal biology. Protein amyloid fibrillization occurs via nucleated polymerization, through non-covalent interactions. As such, protein nanofibril formation is based on a complex interplay between kinetic and thermodynamic factors. The process entails metastable oligomeric species and a highly thermodynamically favoured end state. The kinetics, and the reaction pathway itself, can be influenced by third party moieties, either molecules or surfaces. Specifically, in the biological context, different classes of biomolecules are known to act as catalysts, inhibitors or modifiers of the generic protein fibrillization process. The biological aggregation modifiers reviewed here include lipid membranes of varying composition, glycosaminoglycans and metal ions, with a final word on xenobiotic compounds. The corresponding molecular interactions are critically analysed and placed in the context of the mechanisms of cytotoxicity of the amyloids involved in diverse pathologies and the non-toxicity of functional amyloids (at least towards their biological host). Finally, the utilization of this knowledge towards the design of bio-inspired and biocompatible nanomaterials is explored.
The adaptive acquisition of single DNA segments drives metabolic evolution acrossE. colilineages
Authors: Pang Tin Yau , Lercher Martin J.
Published: June 2017

Even closely related prokaryotes show an astounding diversity in their ability to grow in different nutritional environments1,2. Mechanistically, this diversity arises predominantly through horizontal gene transfer, the exchange of DNA between individuals from different strains3. It has been hypothesized that complex metabolic adaptations – those requiring the acquisition of multiple distinct DNA segments – can evolve via selectively neutral intermediate steps4,5; an alternative explanation rests on the existence of intermediate environments that make each individual DNA acquisition adaptive6However, it is unclear how important changing environments6are compared to neutral explorations of phenotype space5; more fundamentally, it is unknown what fraction of metabolic adaptations are indeed complex. Here, we use metabolic network simulations to show that all 3,363 phenotypic innovations observed in the evolutionary history of 53E. colistrains arose through the acquisition of a single DNA segment; while we found no evidence for the contribution of selectively neutral processes, 10.6% of adaptations to previously unviable environments relied on the support of DNA acquisitions on earlier phylogenetic branches. 97.0% of all metabolic phenotypes accessible for theE. colipan-genome could be bestowed on any ancestral strain by transferring a single DNA segment from one of the extant strains. These results demonstrate an amazing ability of theE. colilineage to quickly adapt to previously inaccessible environments through a single DNA acquisition, an ability likely to be mirrored in other clades of generalist bacteria.
Complex spatio-temporal distribution and genogeographic affinity of mitochondrial DNA haplogroups in 24,216 Danes
Authors: Bybjerg-Grauholm Jonas , Hagen Christian , Goncalves Vanessa F , Baekvad-Hansen Marie , Hansen Christine Soeholm , Hedley Paula L , Kanters Jorgen K , Nielsen Jimmi , Theisen Michael , Mors Ole , Kennedy James , Als Thomas D , Demur Alfonso Buil , Werge Thomas , Nordentoft Merete , Borglum Anders , Mortensen Preben Bo , Hougaard David , Christiansen Michael
Published: June 2017

Mitochondrial DNA (mtDNA) haplogroups (hgs) are evolutionarily conserved sets of mtDNA SNP-haplotypes with characteristic geographical distribution. Associations of hgs with disease and physiological characteristics have been reported, but have frequently not been reproducible. Using 418 mtDNA SNPs on the PsychChip (Illumina), we assessed the spatio-temporal distribution of mtDNA hgs in Denmark in DNA isolated from 24,642 geographically un-biased dried blood spots (DBS), collected from 1981 to 2005 through the Danish National Neonatal Screening program. Geno-geographic affinity (ancestry background) was established with ADMIXTURE using a reference of 100K+ autosomal SNPs in 2,248 individuals from nine populations. The hg distribution was typically Northern European, and hgs were highly variable based on median-joining analysis, suggesting multiple founder events. Considerable heterogeneity and variation in autosomal geno-geographic affinity was observed. Thus, individuals with hg H exhibited 95 %, and U hgs 38.2 % - 92.5 %, Danish ancestry. Significant clines between geographical regions and rural and metropolitan populations were found. Over 25 years, macro-hg L increased from 0.2 % to 1.2 % (p = 1.1*E-10), and M from 1 % to 2.4 % (p = 3.7*E-8). Hg U increased among the R macro-hg from 14.1 % to 16.5 % (p = 1.9*E-3). Geno-geographic affinity, geographical skewedness, and sub-hg distribution suggested that the L, M and U increases are due to immigration. The complex spatio-temporal dynamics and geno-geographic heterogeneity of mtDNA in the Danish population reflect repeated migratory events and, in later years, net immigration. Such complexity may explain the often contradictory and population-specific reports of mito-genomic association with disease.
Harmonization of cortical thickness measurements across scanners and sites
Authors: Fortin Jean-Philippe , Cullen Nicholas , Sheline Yvette I. , Taylor Warren D. , Aselcioglu Irem , Adams Phil , Cooper Crystal , Fava Maurizio , McGrath Patrick J. , McInnis Melvin , Parsey Ramin V. , Phillips Mary L. , Trivedi Madhukar H. , Weissman Myrna M. , Shinohara Russell T.
Published: June 2017

With the proliferation of multi-site neuroimaging studies, there is a greater need for handling non-biological variance introduced by differences in MRI scanners and acquisition protocols. Such unwanted sources of variation, which we refer to as “scanner effects”, can hinder the detection of imaging features associated with clinical covariates of interest and cause spurious findings. In this paper, we investigate scanner effects in two large multi-site studies on cortical thickness measurements, across a total of 11 scanners. We propose a set of general tools for visualizing and identifying scanner effects that are generalizable to other modalities. We then propose to use ComBat, a technique adopted from the genomics literature and recently applied to diffusion tensor imaging data, to combine and harmonize cortical thickness values across scanners. We show that ComBat removes unwanted sources of scan variability while simultaneously increasing the power and reproducibility of subsequent statistical analyses. We also show that ComBat is useful for combining imaging data with the goal of studying life-span trajectories in the brain.
Quartet Sampling distinguishes lack of support from conflicting support in the plant tree of life
Authors: Pease James B. , Brown Joseph W. , Walker Joseph F. , Hinchliff Cody E. , Smith Stephen A.
Published: June 2017

Premise of the Study

Phylogenetic support has been difficult to evaluate within the plant tree of life partly due to the difficulty of distinguishing conflicted versus poorly informed branches. As datasets continue to expand in both breadth and depth, new support measures are needed that are more efficient and informative.

Methods

We describe the Quartet Sampling (QS) method, a quartet-based evaluation system that synthesizes several phylogenetic and genomic analytical approaches. QS characterizes discordance in large-sparse and genome-wide datasets, overcoming issues of alignment sparsity and distinguishing strong conflict from weak support. We test QS with simulations and recent plant phylogenies inferred from variously sized datasets.

Key Results

QS scores demonstrate convergence with increasing replicates and are not strongly affected by branch depth. Patterns of QS support from different phylogenies leads to a coherent understanding of ancestral branches defining key disagreements, including the relationships ofGinkgoto cycads, magnoliids to monocots and eudicots, and mosses to liverworts. The relationships of ANA grade angiosperms, major monocot groups, bryophytes, and fern families are likely highly discordant in their evolutionary histories, rather than poorly informed. QS can also detect discordance due to introgression in phylogenomic data.

Conclusions

The QS method represents an efficient and effective synthesis of phylogenetic tests that offer more comprehensive and specific information on branch support than conventional measures. The QS method corroborates growing evidence that phylogenomic investigations that incorporate discordance testing are warranted to reconstruct the complex evolutionary histories surrounding in particular ANA grade angiosperms, monocots, and non-vascular plants.
Selective maintenance of multiple CRISPR arrays across prokaryotes
Authors: Weissman Jake L. , Fagan William F. , Johnson Philip L.F.
Published: June 2017

Prokaryotes are under nearly constant attack by viral pathogens. To protect against this threat of infection, bacteria and archaea have evolved a wide array of defense mechanisms, singly and in combination. While immune diversity in a single organism likely reduces the chance of pathogen evolutionary escape, it remains puzzling why many prokaryotes also have multiple, seemingly redundant, copies of the same type of immune system. Here, we focus on the highly flexible CRISPR adaptive immune system, which is present in multiple copies in a surprising 28% of the prokaryotic genomes in RefSeq. We use a comparative genomics approach looking across all prokaryotes to demonstrate that, on average, organisms are under selection to maintain more than one CRISPR array. We hypothesize that a tradeoff between memory span and learning speed could select for both “long-term memory” and “short-term memory” CRISPR arrays, and we go on to develop a mathematical model to show that such a tradeoff could, in theory, lead to selection for multiple arrays.
Correlated Light-Serial Scanning Electron Microscopy (CoLSSEM) for ultrastructural visualization of single neuronsin vivo
Authors: Hirabayashi Yusuke , Carlos Tapia Juan , Polleux Franck
Published: June 2017

A challenging aspect of neuroscience revolves around mapping the synaptic connections within neural circuits (connectomics) over scales spanning several orders of magnitude (nanometers to meters). Despite significant improvements in serial section electron microscopy (SSEM) technologies, several major roadblocks have impaired its general applicability to mammalian neural circuits. In the present study, we introduce a new approach that circumvents these roadblocks by adapting a genetically-encoded ascorbate peroxidase (APEX2) as a fusion protein to a membrane-targeted fluorescent reporter (CAAX-Venus), and introduce it in single pyramidal neuronsin vivousing extremely sparsein uterocortical electroporation (IUCE). This approach allows to perform Correlated Light-SSEM (CoLSSEM) on individual neurons, reconstructing their dendritic and axonal arborization in a targeted way via combination of high-resolution confocal microscopy, and subsequently imaging of its ultrastuctural features and synaptic connections with the ATUM-SEM (automated tape-collecting ultramicrotome - scanning electron microscopy) technology. Our method significantly improves the the feasibility of large-scale reconstructions of neurons within a circuit, and bridges the description of ultrastructural features of genetically-identified neurons with their functional and/or structural connectivity, one of the main goal of connectomics.
Stability of Commonly Used Hematological Parameters in Samples Stored at 33°C, 22°C and 4°C
Authors: Jain Ashish , Jain Sanchit , Singh Neha , Aswal Priyanka , Pal Shweta , Meinia Sushant Kumar , Chowdhury Nilotpal
Published: June 2017

Aim

This study aimed to investigate the analytical bias and imprecision in haematological parameters induced by storage at 4°C, 22°C and 33 °C.

Methods

Three K2EDTA anticoagulated vials of blood were collected from each of twenty blood donors and stored at 4°C, 22°C and 33°C respectively. Readings from each vial were taken at 0, 4, 6, 12, 24, 48 and 72 hours after collection on the Sysmex XP-100 analyser. The mean and median shift of the parameters relative to the baseline and the coefficient of variation for each time-temperature combination were calculated. The shift was compared to the maximum acceptable bias.

Results

Haemoglobin, Red Blood Cell Count, White Blood Cell Count, Mean Corpuscular Haemoglobin were stable for at least twenty four hours at 33°C. Haematocrit, Mean Corpuscular Volume and Platelet Counts were stable for less than four hours at 33°C. All the above parameters were stable for longer at 22°C and 4°C. The three-part differential count showed instability within four hours at 33 °C.

Conclusions

Strict pre-analytical control is needed at 33°C or above due to the marked instability of most parameters. However, Haemoglobin, Red Blood Cell Count, White Blood Cell Count and Mean Corpuscular Haemoglobin remain relatively stable even at 33°C.

Key Message

Haematology samples exposed to temperatures of 33°C or above show rapid change in MCV, HCT,MCHC, RDW, Platelet Counts and three-part differential counts. Settings where prolonged exposure to these temperatures cannot be avoided should rely on the more stable parameters of Haemoglobin, RBC Counts, MCH and WBC Counts.
Sperm chemotaxis is driven by the slope of the chemoattractant concentration field
Authors: Ramírez-Gómez H.V. , Jimenez Sabinina V. , Velázquez-Pérez M. , Beltrán C. , Carneiro J. , Wood C.D. , Tuval I. , Darszon A. , Guerrero A.
Published: June 2017

Spermatozoa of marine invertebrates are attracted to their conspecific female gamete by diffusive molecules, called chemoattractants, released from the egg investments in a process known as chemotaxis. The information from the egg chemoattractant concentration field is decoded into intracellular Ca2+concentration ([Ca2+]i) changes that regulate the internal motors that shape the flagellum as it beats. By studying sea urchin species-specific differences in sperm chemoattractant-receptor characteristics we show that receptor density constrains the steepness of the chemoattractant concentration gradient detectable by spermatozoa. Through analyzing different chemoattractant gradient forms, we demonstrate for the first time thatStrongylocentrotus purpuratussperm are chemotactic and this response is consistent with frequency entrainment of two coupled physiological oscillators: i) the stimulus function and ii) the [Ca2+]ichanges. We demonstrate that the slope of the chemoattractant gradients provides the coupling force between both oscillators, arising as a fundamental requirement for sperm chemotaxis.
Generation of Arctic-like Rabies Viruses Containing Chimeric Glycoproteins Enables Serological Potency Studies
Authors: Bentley Emma M. , Ali Ruqiyo , Horton Daniel L. , Corti Davide , Banyard Ashley C. , Fooks Anthony R. , Wright Edward
Published: June 2017

Rabies viruses have the highest case fatality rate of any known virus and are responsible for an estimated 60,000 deaths each year. This is despite the fact that there are highly efficacious vaccines and postexposure prophylaxis available. However, while it is assumed these biologics provide protection against all rabies virus isolates, there are certain subdivisions of RABV lineages, such as within the Arctic-like RABV (AL rabies virus lineage, where data is limited and thus the potency of existing biologics has not been thoroughly assessed. By fusing the Arctic-like rabies virus envelope glycoprotein ecto- and transmembrane domains with the vesicular stomatitis virus cytoplasmic domain, a high titre (7.7 x 105− 6.1 x 106RLU/ml) pseudotyped virus was generated that was subsequently used in a pseudotyped virus neutralisation assay. These results showed that Arctic-like rabies viruses are neutralised to human, canine and feline vaccines and human post-exposure prophylaxis and this was not influenced by the swapping of the cytoplasmic domains (CVS-11 vs CVS-11etmVSVc;r= 0.99,p< 0.0001). This study supports the concept that rabies virus vaccines and newly identified mAbs are able to neutralise rabies virus variants that cluster in a monophyletic clade, referred to as phylogroup I lyssaviruses.
Active-site protein dynamics and solvent accessibility in nativeAchromobacter cycloclastescopper nitrite reductase
Authors: Sen Kakali , Horrell Sam , Kekilli Demet , Yong Chin W. , Keal Thomas W. , Atakisi Hakan , Moreau David W. , Thorne Robert E. , Hough Michael A. , Strange Richard W.
Published: June 2017

Microbial nitrite reductases are denitrifying enzymes that are a major component of the global nitrogen cycle. Multiple structures measured from one crystal (MSOX data) of copper nitrite reductase at 240 K, together with molecular-dynamics simulations, have revealed protein dynamics at the type 2 copper site that are significant for its catalytic properties and for the entry and exit of solvent or ligands to and from the active site. Molecular-dynamics simulations were performed using different protonation states of the key catalytic residues (AspCATand HisCAT) involved in the nitrite-reduction mechanism of this enzyme. Taken together, the crystal structures and simulations show that the AspCATprotonation state strongly influences the active-site solvent accessibility, while the dynamics of the active-site `capping residue' (IleCAT), a determinant of ligand binding, are influenced both by temperature and by the protonation state of AspCAT. A previously unobserved conformation of IleCATis seen in the elevated temperature series compared with 100 K structures. DFT calculations also show that the loss of a bound water ligand at the active site during the MSOX series is consistent with reduction of the type 2 Cu atom.
Supramolecular interactions in carboxylate and sulfonate salts of 2,6-diamino-4-chloropyrimidinium
Authors: Mohana Marimuthu , Thomas Muthiah Packianathan , Butcher Ray J.
Published: June 2017

Two new salts, namely 2,6-diamino-4-chloropyrimidinium 2-carboxy-3-nitrobenzoate, C4H6ClN4
+·C8H4NO6
−, (I), and 2,6-diamino-4-chloropyrimidinium p-toluenesulfonate monohydrate, C4H6ClN4
+·C7H7O3S−·H2O, (II), have been synthesized and characterized by single-crystal X-ray diffraction. In both crystal structures, the N atom in the 1-position of the pyrimidine ring is protonated. In salt (I), the protonated N atom and the amino group of the pyrimidinium cation interact with the carboxylate group of the anion through N—H...O hydrogen bonds to form a heterosynthon with an R
2
2(8) ring motif. In hydrated salt (II), the presence of the water molecule prevents the formation of the familiar R
2
2(8) ring motif. Instead, an expanded ring [i.e.
R
3
2(8)] is formed involving the sulfonate group, the pyrimidinium cation and the water molecule. Both salts form a supramolecular homosynthon [R
2
2(8) ring motif] through N—H...N hydrogen bonds. The molecular structures are further stabilized by π–π stacking, and C=O...π, C—H...O and C—H...Cl interactions.
The structure of a complex of the lactonohydrolase zearalenone hydrolase with the hydrolysis product of zearalenone at 1.60 Å resolution
Authors: Qi Qi , Yang Wen-Jing , Zhou Hu-Jian , Ming Deng-Ming , Sun Kai-Lei , Xu Tian-Yu , Hu Xiao-Jian , Lv Hong
Published: June 2017

Zearalenone hydrolase (ZHD) is an α/β-hydrolase that detoxifies and degrades the lactone zearalenone (ZEN), a naturally occurring oestrogenic mycotoxin that contaminates crops. Several apoenzyme and enzyme–substrate complex structures have been reported in the resolution range 2.4–2.6 Å. However, the properties and mechanism of this enzyme are not yet fully understood. Here, a 1.60 Å resolution structure of a ZHD–product complex is reported which was determined from a C-terminally His6-tagged ZHD crystal soaked with 2 mMZEN for 30 min. It shows that after the lactone-bond cleavage, the phenol-ring region moves closer to residues Leu132, Tyr187 and Pro188, while the lactone-ring region barely moves. Comparisons of the ZHD–substrate and ZHD–product structures show that the hydrophilic interactions change, especially Trp183 N∊1, which shifts from contacting O2 to O12′, suggesting that Trp183 is responsible for the unidirectional translational movement of the phenol ring. This structure provides information on the final stage of the catalytic mechanism of zearalenone hydrolysis.
Full-length nisin immunity protein NisI fromLactococcus lactisin a lipid-free form: crystallization and X-ray analysis
Authors: Jeong Jin Hee , Ha Sung Chul
Published: June 2017

NisI is a lantibiotic-binding lipoprotein that is specific for nisin. Nisin-producing microorganisms use NisI as an immunity protein for self-protection against nisin. Here, the purification, crystallization and preliminary X-ray diffraction of full-length NisI fromLactobacillus lactisin a lipid-free form (NisI22-C) are reported. Importantly, reductive methylation of the lysine residues in NisI22-Cwas essential for initial crystallization. Only methylated NisI22-Ccrystallized. The optimized crystals of methylated NisI22-Cwere grown in 30–40 mMammonium sulfate, 0.1 Msodium acetate pH 4.6, 16–18% PEG 4000 at 295 K and diffracted to 1.9 Å resolution. The crystal belonged to space groupP212121, with unit-cell parametersa= 45.99,b= 76.67,c= 76.39 Å, α = β = γ = 90.0°. Assuming the presence of one molecule in the asymmetric unit, the estimated Matthews coefficient (VM) is 2.58 Å3 Da−1and the estimated solvent content is 52.3%.
Synthesis and characterization of 3-methyl-6-[(propynyloxy)methyl]-1,4-dioxane-2,5-dione
Authors: Elkin Igor , Maris Thierry , Hildgen Patrice
Published: June 2017

The number of known asymmetrically substituted hemilactides, important precursors for obtaining regular derivatives of polylactide polymers, is still limited and structural characterization of most of them is incomplete. In the title racemic 1,4-dioxane-2,5-dione derivative, C9H10O5, the hemilactide heterocycle exhibits a twist-boat conformation. The bulkier propynyloxymethyl group is in an axial position with agaucheconformation for the CH2–O–CH2–C segment. In the crystal, molecules are linked by pairs of C—H...O hydrogen bonds, forming inversion dimers. The dimers are linked by further C—H...O contacts, forming a three-dimensional structure.
Crystal structure ofN′-[2-(benzo[d]thiazol-2-yl)acetyl]-4-methylbenzenesulfonohydrazide
Authors: Azzam Rasha A. , Elgemeie Galal H. , Elsayed Rasha E. , Jones Peter G.
Published: June 2017

In the title compound, C16H15N3O3S2, the hydrazide N atom bonded to the C=O group is planar, whereas that bonded to the SO2group is pyramidally coordinated. The interplanar angle between the ring systems is 40.71 (3)°. Molecules are connected into ribbons parallel to thebaxis by two classical hydrogen bonds N—H...O=C and N—H...Nthiazole.
Synthesis and crystal structure of dichlorido(1,10-phenanthroline-κ2N,N′)gold(III) hexafluoridophosphate
Authors: Ferraz de Paiva Raphael Enoque , Nakahata Douglas Hideki , Corbi Pedro Paulo
Published: June 2017

A gold(III) salt of composition [AuCl2(C12H8N2)]PF6was prepared and characterized by elemental and mass spectrometric analysis (ESI(+)–QTOF–MS),1H nuclear magnetic resonance measurements and by single-crystal X-ray diffraction. The square-planar coordination sphere of AuIIIcomprises the bidentate 1,10-phenanthroline ligand and two chloride ions, with the AuIIIion only slightly shifted from the least-squares plane of the ligating atoms (r.m.s. = 0.018 Å). In contrast to two other previously reported AuIII-phenantroline structures that are stabilized by interactions involving the chlorido ligands, the packing of the title compound does not present these features. Instead, the hexafluoridophosphate counter-ion gives rise to anion...π interactions that are a crucial factor for the crystal packing.
The sustainable executive: antecedents of managerial long-term orientation
Authors: Sternad Dietmar , Kennelly James J.
Published: June 2017

Purpose

The purpose of this paper is to explain how managers incorporate long-term thinking in their decision-making processes as an antipode to a widely criticized managerial short-termism. For this purpose, the authors present a model of the influence of institutional, cultural and individual temporal factors on managerial long-term orientation (LTO).

Design/methodology/approach

This conceptual paper is based on a multidisciplinary review of the literature on the causes of managerial LTO.

Findings

It is proposed that managerial LTO is influenced by cultural and institutional factors on both a societal and an organizational level, as well as by managers’ individual temporal predispositions and the strengths of relational commitments with different stakeholder groups. It is further expected that managerial LTO has an influence on sustainability-related managerial behavior.

Practical implications

As the presented model reveals the main factors that orient managers toward the long run in their decisions, it can also be used as a framework to evaluate policies to curb managerial myopia on both an organizational and a societal level.

Social implications

As sustainability is intrinsically linked with the ability to think and act in the long term, understanding the factors that influence managerial LTO can also contribute to building more sustainable organizations.

Originality/value

One of the main contributions of this paper is that it highlights the link between reciprocal relationships and LTO, an aspect that has not yet been the focus of the literature on the temporal orientation of managers.
Toward a dynamic balanced scorecard model for humanitarian relief organizations’ performance management
Authors: Anjomshoae Ali , Hassan Adnan , Kunz Nathan , Wong Kuan Yew , de Leeuw Sander
Published: June 2017

Purpose

In recent years, the balanced scorecard (BSC) has received considerable interest among practitioners for managing their organization’s performance. Unfortunately existing BSC frameworks, particularly for humanitarian supply chains, lack causal relationships among performance indicators, actions, and outcomes. They are not able to provide a dynamic perspective of the organization with factors that drive the organization’s behavior toward its mission. Lack of conceptual references seems to hinder the development of a performance measurement system toward this direction. The paper aims to discuss these issues.

Design/methodology/approach

The authors formulate the interdependencies among key performance indicators (KPIs) in terms of cause-and-effect relationships based on published case studies reported in international journals from 1996 to 2017.

Findings

This paper aims to identify the conceptual interdependencies among KPIs and represent them in the form of a conceptual model.

Research limitations/implications

The study was solely based on relevant existing literature. Therefore further practical research is needed to validate the interdependencies of performance indicators in the strategy map.

Practical implications

The proposed conceptual model provides the structure of a dynamic balanced scorecard (DBSC) in the humanitarian supply chain and should serve as a starting reference for the development of a practical DBSC model. The conceptual framework proposed in this paper aims to facilitate further research in developing a DBSC for humanitarian organizations (HOs).

Originality/value

Existing BSC frameworks do not provide a dynamic perspective of the organization. The proposed conceptual framework is a useful reference for further work in developing a DBSC for HOs.
Flying maggots: a smart logistic solution to an enduring medical challenge
Authors: Tatham Peter , Stadler Frank , Murray Abigail , Shaban Ramon Z.
Published: June 2017

Purpose

Whilst there is a growing body of research which discusses the use of remotely piloted aircraft systems (RPAS) (otherwise known as “drones”) to transport medical supplies, almost all reported cases employ short range aircraft. The purpose of this paper is to consider the advantages and challenges inherent in the use of long endurance remotely piloted aircraft systems (LE-RPAS) aircraft to support the provision of medical supplies to remote locations – specifically “medical maggots” used in maggot debridement therapy (MDT) wound care.

Design/methodology/approach

After introducing both MDT and the LE-RPAS technology, the paper first reports on the outcomes of a case study involving 11 semi-structured interviews with individuals who either have experience and expertise in the use of LE-RPAS or in the provision of healthcare to remote communities in Western Australia. The insights gained from this case study are then synthesised to assess the feasibility of LE-RPAS assisted delivery of medical maggots to those living in such geographically challenging locations.

Findings

No insuperable challenges to the concept of using LE-RPAS to transport medical maggots were uncovered during this research – rather, those who contributed to the investigations from across the spectrum from operators to users, were highly supportive of the overall concept.

Practical implications

The paper offers an assessment of the feasibility of the use of LE-RPAS to transport medical maggots. In doing so, it highlights a number of infrastructure and organisational challenges that would need to be overcome to operationalise this concept. Whilst the particular context of the paper relates to the provision of medical support to a remote location of a developed country, the core benefits and challenges that are exposed relate equally to the use of LE-RPAS in a post-disaster response. To this end, the paper offers a high-level route map to support the implementation of the concept.

Social implications

The paper proposes a novel approach to the efficient and effective provision of medical care to remote Australian communities which, in particular, reduces the need to travel significant distances to obtain treatment. In doing so, it emphasises the importance in gaining acceptance of both the use of MDT and also the operation of RPAS noting that these have previously been employed in a military, as distinct from humanitarian, context.

Originality/value

The paper demonstrates how the use of LE-RPAS to support remote communities offers the potential to deliver healthcare at reduced cost compared to conventional approaches. The paper also underlines the potential benefits of the use of MDT to address the growing wound burdens in remote communities. Finally, the paper expands on the existing discussion of the use of RPAS to include its capability to act as the delivery mechanism for medical maggots.
Why are Generation Y consumers the most likely to complain and repurchase?
Authors: Soares Raquel Reis , Zhang Ting Ting (Christina) , Proença João F. , Kandampully Jay
Published: June 2017

Purpose

The purpose of this paper is twofold: to examine generational differences in complaint and post-recovery behaviors after service failures and recoveries, and to investigate the key factors that relate to Generation Y consumers’ responses.

Design/methodology/approach

In a two-stage approach, Study 1 investigates generational differences in the complaint and repurchase behaviors of a vast sample of more than 36,000 customers. Study 2 examines which factors influence Generation Y consumers’ decisions to complain and to repurchase.

Findings

Across four generational cohorts (the Silent Generation, Baby Boomers, Generation X, and Generation Y), consumers in Generation Y are the most likely to complain about service failures and repurchase after a satisfactory service recovery. The service recovery paradox thus is a generational feature. Generation Y’s unique characteristics – being tech savvy, heavily influenced by peers, and untrusting of brands – relate closely to their complaint and repurchase patterns. These prolific users of social media tend to stay with a service provider after experiencing satisfactory recovery but are more inclined to complain.

Originality/value

This study contributes to service management literature by revealing generational differences in customers’ complaint behavior and responses to recovery efforts, while also testing repurchase behavior rather than just behavioral intentions. This study provides valuable insights into the unique factors that influence Generation Y consumers’ complaint and post-recovery responses.
Business service outsourcing in manufacturing firms: an event study
Authors: Eggert Andreas , Böhm Eva , Cramer Christina
Published: June 2017

Purpose

Many manufacturing firms entrust partners to provide services on their behalf. However, it is not clear whether and when firms can capture the potential value advantages of outsourcing business services. The purpose of this paper is to investigate the effects of different types of business service outsourcing on firm value.

Design/methodology/approach

The paper uses event study methodology to estimate the impact of business service outsourcing announcements on abnormal returns of publicly traded manufacturing companies in Europe.

Findings

External service outsourcing that directly affects the company’s customers leads to more favorable outcomes than internal service outsourcing. This effect is contingent on the strategic outsourcing intention, the service’s reliance on technology, and the choice of the outsourcing partner.

Research limitations/implications

Findings show that firm value depends critically on the service value it delivers to customers. Future research could explore further contingency variables, and investigate the role of service outsourcing networks and relationships.

Practical implications

The insights of this study help managers to decide why, how, and to whom they should outsource their business services, as well as how to justify their outsourcing decisions, and how to communicate them toward the financial markets.

Originality/value

This research sheds light on the value implications of outsourcing decisions. Two types of business service outsourcing are distinguished, namely, internal and external. Furthermore, the study enhances our understanding of a contingency perspective on service outsourcing decisions.