bluuebunny/crossref_metadata_2025 huggingface dataset:
Altered Macular Microvasculature in Mild Cognitive Impairment and Alzheimer Disease
Authors: Jiang Hong , Wei Yantao , Shi Yingying , Wright Clinton B. , Sun Xiaoyan , Gregori Giovanni , Zheng Fang , Vanner Elizabeth A. , Lam Byron L. , Rundek Tatjana , Wang Jianhua
Published: October 2017

Background:

The goal of the present study was to analyze the macular microvacular network in mild cognitive impirment (MCI) and Alzheimer disease (AD).

Methods:

Twelve patients with AD and 19 patients with MCI were recruited together with 21 cognitively normal controls with a similar range of ages. Optical coherence tomography angiography was used to image the retinal microvascular network at the macular region, including retinal vascular network (RVN), superficial vascular plexus (SVP), and deep vascular plexus (DVP). Fractal analysis (box counting, Dbox) representing the microvascular density was performed in different annular zones and quadrantal sectors. The macular ganglion cell–inner plexiform layer (GC-IPL) thickness was measured using Zeiss OCT. The relationship between the retinal microvasculature and clinical manifestations was analyzed.

Results:

Patients with AD had lower densities of RVN, SVP, and DVP in the annulus, from 0.6 to 2.5 mm in diameter (P < 0.05) in comparison with controls. Patients with MCI had lower density of DVP in the superior nasal quadrant (P < 0.05) than that of the controls. There were no significant differences of GC-IPL thickness among groups (P > 0.05). There was a trend of vascular density loss from control to MCI then AD (P < 0.05). Retinal microvascular density of DVP was correlated with GC-IPL thickness (P < 0.05) in patients with AD, but not in patients with MCI and controls.

Conclusions:

Patients with AD had less density of retinal microvascular networks than controls. Our findings suggest the presence of retinal microvascular dysfunction in AD.
Integrating nanomedicine and imaging
Authors: Pérez-Medina Carlos , Hak Sjoerd , Reiner Thomas , Fayad Zahi A. , Nahrendorf Matthias , Mulder Willem J. M.
Published: October 2017

Biomedical engineering and its associated disciplines play a pivotal role in improving our understanding and management of disease. Motivated by past accomplishments, such as the clinical implementation of coronary stents, pacemakers or recent developments in antibody therapies, disease management now enters a new era in which precision imaging and nanotechnology-enabled therapeutics are maturing to clinical translation. Preclinical molecular imaging increasingly focuses on specific components of the immune system that drive disease progression and complications, allowing the
in vivo
study of potential therapeutic targets. The first multicentre trials highlight the potential of clinical multimodality imaging for more efficient drug development. In this perspective, the role of integrating engineering, nanotechnology, molecular imaging and immunology to yield precision medicine is discussed.

This article is part of the themed issue ‘Challenges for chemistry in molecular imaging’.
Propagation of spike timing and firing rate in feedforward networks reconstitutedin vitro
Authors: Barral Jérémie , Wang Xiao-Jing , Reyes Alex
Published: October 2017

The manner in which information is transferred and transformed across brain regions is yet unclear. Theoretical analyses of idealized feedforward networks suggest that several conditions have to be satisfied in order for activity to propagate faithfully across layers. Verifying these concepts experimentally in networks has not been possible owing to the vast number of variables that must be controlled. Here, we culture cortical neurons in a chamber with sequentially connected compartments, optogenetically stimulate individual neurons in the first layer with high spatiotemporal resolution, and monitor the subthreshold and suprathreshold potentials in subsequent layers. In the first layer, a brief stimulus with different temporal precisions resulted in the modulation of the firing rate. This temporal to rate transformation was propagated to other layers as a sustained response, thereby preserving rate information. This novel mode of propagation occurred in the balanced excitatory-inhibitory regime and is mediated by NMDA-mediated synapses activated by recurrent activity.
An atlas of genetic variation for linking pathogen-induced cellular traits to human disease
Authors: Wang Liuyang , Pittman Kelly J. , Barker Jeffrey R. , Salinas Raul E. , Stanaway Ian B. , Williams Graham D. , Carroll Robert J. , Balmat Tom , Ingham Andy , Gopalakrishnan Anusha M. , Gibbs Kyle D. , Antonia Alejandro L. ,   The eMERGE Network, Heitman Joseph , Lee Soo Chan , Jarvick Gail P. , Denny Joshua C. , Horner Stacy M. , Delong Mark R. , Valdivia Raphael H. , Crosslin David R. , Ko Dennis C.
Published: October 2017

Genome-wide association studies (GWAS) have identified thousands of genetic variants associated with disease. To facilitate moving from associations to disease mechanisms, we leveraged the role of pathogens in shaping human evolution with the Hi-HOST Phenome Project (H2P2): a catalog of cellular GWAS comprised of 79 phenotypes in response to 8 pathogens in 528 lymphoblastoid cell lines. Seventeen loci surpass genome-wide significance (p<5×10−8) for phenotypes ranging from pathogen replication to cytokine production. Combining H2P2 with clinical association data from the eMERGE Network and experimental validation revealed evidence for mechanisms of action and connections with diseases. We identified a SNP near CXCL10 as a cis-cytokine-QTL and a new risk factor for inflammatory bowel disease. A SNP in ZBTB20 demonstrated pleiotropy, partially mediated through NFκB signaling, and was associated with viral hepatitis. Data are available in an H2P2 web portal to facilitate further interpreting human genome variation through the lens of cell biology.
Transcranial recording of electrophysiological neural activity in the rodent brain in vivo using functional photoacoustic imaging of near-infrared voltage-sensitive dye
Authors: Kang Jeeun , Zhang Haichong K. , Kadam Shilpa D. , Fedorko Julie , Valentine Heather , Malla Adarsha P. , Yan Ping , Harraz Maged M. , Kang Jin U. , Rahmim Arman , Gjedde Albert , Loew Leslie M. , Wong Dean F. , Boctor Emad M.
Published: October 2017

Minimally-invasive monitoring of electrophysiological neural activities in real-time—that enables quantification of neural functions without a need for invasive craniotomy and the longer time constants of fMRI and PET—presents a very challenging yet significant task for neuroimaging. In this paper, we present in vivo functional PA (fPA) imaging of chemoconvulsant rat seizure model with intact scalp using a fluorescence quenching-based cyanine voltage-sensitive dye (VSD) characterized by a lipid vesicle model mimicking different levels of membrane potential variation. The framework also involves use of a near-infrared VSD delivered through the blood-brain barrier (BBB), opened by pharmacological modulation of adenosine receptor signaling. Our normalized time-frequency analysis presented in vivo VSD response in the seizure group significantly distinguishable from those of the control groups at sub-mm spatial resolution. Electroencephalogram (EEG) recording confirmed the changes of severity and frequency of brain activities, induced by chemoconvulsant seizures of the rat brain. The findings demonstrate that the near-infrared fPA VSD imaging is a promising tool for in vivo recording of brain activities through intact scalp, which would pave a way to its future translation.
Galectin-3 andN-acetylglucosamine promote myogenesis and improve skeletal muscle function in themdxmodel of Duchenne muscular dystrophy
Authors: Rancourt Ann , Dufresne Sébastien , St-Pierre Guillaume , Lévesque Julie-Christine , Nakamura Haruka , Kikuchi Yodai , Satoh Masahiko S. , Frenette Jérôme , Sato Sachiko
Published: October 2017

The muscle membrane, sarcolemma, must be firmly attached to the basal lamina. The failure of proper attachment results in muscle injury, which is the underlying cause of Duchenne muscular dystrophy (DMD), where mutations in the dystrophin gene disrupts the firm adhesion. In DMD patients, even moderate contraction causes damage, leading to progressive muscle degeneration. The damaged muscles are repaired through myogenesis. Consequently, myogenesis is highly active in DMD patients, and the repeated activation of myogenesis leads to the exhaustion of the myogenic stem cells. Therefore, approaches to reducing the risk of the exhaustion are to develop a treatment that strengthens the interaction between the sarcolemma and the basal lamina, and increases the efficiency of myogenesis. Galectin-3 is an oligosaccharide-binding protein and known to be involved in cell-cell interactions and cell-matrix interactions. Galectin-3 is expressed in myoblasts and skeletal muscle while its function in muscle remains elusive. In this study, we found evidence that galectin-3 and the monosaccharideN-acetylglucosamine, which increases the ligands (oligosaccharides) of galectin-3, promotes myogenesisin vitro. Moreover, in themdxmouse model of DMD, treatment withN-acetylglucosamine increased the muscle force production. Our results demonstrate that treatment with N-acetylglucosamine can mitigate the burden of DMD.
Cluster Headache: Comparing Clustering Tools for 10X Single Cell Sequencing Data
Authors: Freytag Saskia , Lonnstedt Ingrid , Ng Milica , Bahlo Melanie
Published: October 2017

The commercially available 10X Genomics protocol to generate droplet-based single cell RNA-seq (scRNA-seq) data is enjoying growing popularity among researchers. Fundamental to the analysis of such scRNA-seq data is the ability to cluster similar or same cells into non-overlapping groups. Many competing methods have been proposed for this task, but there is currently little guidance with regards to which method offers most accuracy. Answering this question is complicated by the fact that 10X Genomics data lack cell labels that would allow a direct performance evaluation. Thus in this review, we focused on comparing clustering solutions of a dozen methods for three datasets on human peripheral mononuclear cells generated with the 10X Genomics technology. While clustering solutions appeared robust, we found that solutions produced by different methods have little in common with each other. They also failed to replicate cell type assignment generated with supervised labeling approaches. Furthermore, we demonstrate that all clustering methods tested clustered cells to a large degree according to the amount of genes coding for ribosomal protein genes in each cell.
Modification of scale-free electrophysiological activity induced by changes in excitatory-inhibitory balance is governed by the dynamics of multiple oscillatory relaxation processes
Authors: Muthukumaraswamy Suresh D , Liley David TJ
Published: October 2017

Neurophysiological recordings are dominated by arhythmical activity whose spectra can be characterised by power-law functions, and on this basis are often referred to as reflecting scale-free brain dynamics (1/fβ). Relatively little is known regarding the neural generators and temporal dynamics of this arhythmical behaviour compared to rhythmical behaviour. Here we used Irregularly Resampled AutoSpectral Analysis (IRASA) to quantifyβ, in both the high (5-100 Hz,βhf) and low frequency bands (0.1-2.5 Hz,βlfin EEG/MEG/ECoG recordings and to separate arhythmical from oscillatory modes of activity, such as, alpha rhythms. In MEG/EEG/ECoG data, we demonstrate that oscillatory alpha power dynamically correlates over time withβhfand similarly, participants with higher rhythmical alpha power have higherβhf). In a series of MEG investigations using the GABA reuptake inhibitor tiagabine, the glutamatergic AMPA receptor antagonist perampanel, the NMDA receptor antagonist ketamine and the mixed partial serotonergic agonist LSD we reveal systematic effects of excitation-inhibition balance on bothβhfandβlf. Additionally, strong modulations ofβhfare seen in monkey ECoG data during general anaesthesia using propofol and ketamine. Surrogate data analysis demonstrates that arhythmical activity is generated by both linear and non-linear schemes, with non-linear effects emerging at critical boundaries. We develop and test a unifying model which can explain, the 1/f nature of electrophysiological spectra, their dynamic interaction with oscillatory rhythms as well as the sensitivity of 1/f activity to excitation-inhibition balance by considering electrophysiological spectra as being generated by a collection of stochastically perturbed damped oscillators having a distribution of relaxation rates.
A miniaturized threshold-triggered acceleration data-logger for recording burst movements of aquatic animals
Authors: Nishiumi Nozomi , Matsuo Ayane , Kawabe Ryo , Payne Nicholas , Huveneers Charlie , Watanabe Yuuki Y. , Kawabata Yuuki
Published: October 2017

Animal-borne accelerometers are effective tools for quantifying the kinematics of animal behaviors, such as swimming, running, and flying, under natural conditions. However, quantifying burst movements of small and agile aquatic animals (e.g., small teleost fish), such as during predatory behavior, or while fleeing, remains challenging. To capture the details of burst movements, accelerometers need to sample at a very high frequency, which will inevitably shorten the duration of the recording or increase the size of the device. To overcome this problem, we developed a high-frequency acceleration data-logger that can be triggered by a manually-defined acceleration threshold, thus allowing the selective measurement of animal burst movements. We conducted experiments under laboratory and field conditions to examine the performance of the logger. The laboratory experiment using red seabream (Pagrus major) showed that the new logger could measure the kinematics of their escape behaviors (i.e., body beat cycles and maximum acceleration values). The field experiment using free-swimming yellowtail kingfish (Seriola lalandi) showed that the loggers trigger correctly (i.e., of the 18 burst movements, 17 were recorded by the loggers). We suggest that this new logger can be applied to measure the burst movements of various small and agile animals, whose movements may be otherwise difficult to measure.
Mud sticks after all: Chronically implanted microelectrodes but not electrical stimulation causec-fosexpression along their trajectory
Authors: Pflüger Patrick , Pinnell Richard C. , Martini Nadja , Hofmann Ulrich G.
Published: October 2017

The goal of CNS implanted devices is to build a stable brain-machine-interface. The brain tissue response to the foreign body limits the functionality and viability of this brain-machine connection. Notably the astrocytic glial scar formation and inflammation with resulting neuronal cell loss is considered to be responsible for the signal deterioration over time. We chronically implanted a polyimide microelectrode in the dorsolateral striatum of rats. First, we analyzed thec-fosimmunoreactivity following high frequency stimulation (HFS) of the dorsolateral striatum and second, using GFAP and ED1 immunocytochemistry, the brain tissue response. Acute as well as chronic HFS showed no significant change of neuronalc-fosexpression in the dorsolateral striatum and corresponding cortical areas. We found that the sole chronic implantation of a polyimide microelectrode leads to a reaction of the surrounding neurons, i.e.c-fosexpression, along the implantation trajectory. We also observed the formation of a glial scar around the microelectrode with a low number of inflammation cells. Histological and statistical analysis of NeuN positive cells showed no ‘kill zone’, which accompanied neuronal cell death around the implantation site.
Coral reef carbonate budgets and ecological drivers in the naturally high temperature and high alkalinity environment of the Red Sea
Authors: Roik Anna , Röthig Till , Pogoreutz Claudia , Voolstra Christian R.
Published: October 2017

The coral structural framework is crucial for maintaining reef ecosystem function and services. In the central Red Sea, a naturally high alkalinity is beneficial to reef growth, but rising water temperatures impair the calcification capacity of reef-building organisms. However, it is currently unknown how beneficial and detrimental factors affect the balance between calcification and erosion, and thereby the overall growth of the reef framework. To provide insight into present-day carbonate budgets and reef growth dynamics in the central Red Sea, we measuredin situnet-accretion and net-erosion rates (Gnet) by deployment of limestone blocks and estimated census-based carbonate budgets (Gbudget) in four reef sites along a cross-shelf gradient (25 km). We assessed abiotic variables (i.e., temperature, inorganic nutrients, and carbonate system variables) and biotic drivers (i.e., calcifier and bioeroder abundances). On average, total alkalinity AT(2346 - 2431 μmol kg−1), aragonite saturation state (4.5 - 5.2 Ωa), and pCO2(283 -315 μatm) were close to estimates of pre-industrial global ocean surface waters. Despite these calcification-favorable carbonate system conditions, Gnetand Gbudgetencompassed positive (offshore) and negative net-production (midshore-lagoon and exposed nearshore site) estimates. Notably, Gbudgetmaxima were lower compared to reef growth from pristine Indian Ocean sites. Yet, a comparison with historical data from the northern Red Sea suggests that overall reef growth in the Red Sea has likely remained similar since 1995. When assessing sites across the shelf gradient, ATcorrelated well with reef growth rates (ρ = 0.89), while temperature was a weaker, negative correlate (ρ = −0.71). Further, ATexplained about 65 % of Gbudgetin a best fitting distance-based linear model. Interestingly, parrotfish abundances added up to 82% of explained variation, further substantiating recent studies highlighting the importance of parrotfish to reef ecosystem function. Our study provides a baseline that will be particularly useful in assessing future trajectories of reef growth capacities in the Red Sea under continuous ocean warming and acidification.
Improved imputation of summary statistics for admixed populations
Authors: Rüeger Sina , McDaid Aaron , Kutalik Zoltán
Published: October 2017

Motivation

Summary statistics imputation can be used to infer association summary statistics of an already conducted, genotype-based meta-analysis to higher ge-nomic resolution. This is typically needed when genotype imputation is not feasible for some cohorts. Oftentimes, cohorts of such a meta-analysis are variable in terms of (country of) origin or ancestry. This violates the assumption of current methods that an external LD matrix and the covariance of the Z-statistics are identical.

Results

To address this issue, we present variance matching, an extention to the existing summary statistics imputation method, which manipulates the LD matrix needed for summary statistics imputation. Based on simulations using real data we find that accounting for ancestry admixture yields noticeable improvement only when the total reference panel size is > 1000. We show that for population specific variants this effect is more pronounced with increasing FST.
Epidermal expression of a sterol biosynthesis gene regulates root growth by a non-cell autonomous mechanism inArabidopsis
Authors: Short Eleri , Pullen Margaret , Imriz Gul , Liu Dongbin , Cope-Selby Naomi , Smertenko Andrei , Hussey Patrick J. , Topping Jennifer F. , Lindsey Keith
Published: October 2017

The epidermis has been hypothesized to play a signalling role during plant development. One class of mutants showing defects in signal transduction and radial patterning are those in sterol biosynthesis. The expectation is that sterol biosynthesis is a constitutive cell-autonomous process for the maintenance of basic cellular functions. TheHYDRA1(HYD1) gene of Arabidopsis encodes an essential sterol Δ8-Δ7 isomerase, and althoughhyd1mutant seedlings are defective in radial patterning of several tissues, we show that theHYD1gene is expressed primarily in the root epidermis. Cell type-specific transgenic activation ofHYD1transcription reveals thatHYD1expression in the epidermis ofhyd1null mutants is sufficient to rescue root patterning and growth. Unexpectedly, expression ofHYD1in the vascular tissues and root meristem, though not endodermis or pericycle, also leads to phenotypic rescue. Phenotypic rescue is associated with rescued patterning of the PIN1 and PIN2 auxin efflux carriers. The importance of the epidermis is in part due to its role as a site for tissue-specific sterol biosynthesis, and auxin is a candidate for a non-cell autonomous signal.
Chromosome loss rate in cells of different ploidy can be explained by spindle self-organization
Authors: Jelenić Ivan , Selmecki Anna M. , Laan Liedewij , Pavin Nenad
Published: October 2017

The mitotic spindle segregates chromosomes and minimizes chromosome loss for the specific number of chromosomes present in an organism. In Saccharomyces cerevisiae, for example, haploid and diploid cells are part of the sexual life cycle and have a thousand times lower rate of chromosome loss than tetraploid cells. Currently it is unclear what constrains the number of chromosomes that can be segregated with high fidelity in an organism. Here we developed a mathematical model to study if different rates of chromosome loss in cells with different ploidy can arise from changes in (1) spindle dynamics and (2) a maximum duration of mitotic arrest, after which cells enter anaphase. Our model reveals how small increases in spindle assembly time can result in exponential differences in rate of chromosomes loss between cells of increasing ploidy and predicts the maximum duration of mitotic arrest.
Predominant Patterns of Splicing Evolution on Human, Chimpanzee, and Macaque Evolutionary Lineages
Authors: Xiong Jieyi , Jiang Xi , Ditsiou Angeliki , Gao Yang , Sun Jing , Lowenstein Elijah D. , Huang Shuyun , Khaitovich Philipp
Published: October 2017

Although splicing is widespread and evolves rapidly among species, the mechanisms driving this evolution, as well as its functional implications, are not yet fully understood. We analyzed the evolution of splicing patterns based on transcriptome data from five tissues of humans, chimpanzees, rhesus macaques, and mice. In total, 1,526 exons and exon sets from 1,236 genes showed significant splicing differences among primates. More than 60% of these differences represent constitutive-to-alternative exon transitions while an additional 25% represent changes in exon inclusion frequency. These two dominant evolutionary patterns have contrasting conservation, regulation, and functional features. The sum of these features indicates that, despite their prevalence, constitutive-to-alternative exon transitions do not substantially contribute to long-term functional transcriptome changes. Conversely, changes in exon inclusion frequency appear to be functionally relevant, especially for changes taking place in the brain on the human evolutionary lineage.
Reducing Pollen Dispersal using Forest Windbreaks
Authors: Meyer Thomas , Sagun Vernie , Auer Carol
Published: October 2017

The adoption of genetically engineered (GE) crops has created a demand for practical methods to mitigate pollen dispersal and gene flow. The goal of this project was to measure the ability of a narrow forest windbreak to reduce downwind pollen fluxes from switchgrass (Panicum virgatum L.), a North American grass and model biofuels feedstock. Switchgrass fields were established in two identical plots where one had a forest windbreak and the other was in an open (control) site. Switchgrass reproduction, pollen dispersal, wind speed, and wind direction were measured over two years. Daily release of switchgrass pollen peaked at 11:00-13:30 during a flowering period that lasted about 44 days. The best estimate for switchgrass pollen source strength (PSS) was 141 × 109 pollen/season/hectare for fields planted at commercial densities. The forest windbreak consistently decreased downwind switchgrass pollen concentrations by 333-20,000 fold compared to the control plot which had a 58-77 fold decrease due to downwind distance alone. These results suggest that forest windbreaks could be used as a barrier to reduce pollen dispersal and gene flow from switchgrass and other crops.

Research Highlight

A narrow forest windbreak greatly decreased downwind pollen concentrations from a switchgrass field suggesting that trees can reduce crop gene flow, enhance coexistence between farming systems, and provide ecosystem services.
Measuring Selection Across HIV Gag: Combining Physico-Chemistry and Population Genetics
Authors: Johnson Elizabeth , Gilchrist Michael A.
Published: October 2017

We present physico-chemical based model grounded in population genetics. Our model predicts the stationary probability of observing an amino acid residue at a given site. Its predictions are based on the physico-chemical properties of the inferred optimal residue at that site and the sensitivity of the protein’s functionality to deviation from the physico-chemical optimum at that site. We contextualize our physico-chemical model by comparing our model fit and parameters it to the more general, but less biologically meaningful entropy based metric: site sensitivity or 1/E. We show mathematically that our physico-chemical model is a more restricted form of the entropy model and how 1/Eis proportional to the log-likelihood of a parameter-wise ‘saturated’ model. Next, we fit both our physico-chemical and entropy models to sequences for subtype C’s Gag poly-protein in the LANL HIV database. Comparing our model’s site sensitivity parametersG′ to 1/Ewe find they are highly correlated. We also compare the ability ofG′, 1/E, and other indirect measures of HIV fitness to empiricalin vitroandin vivomeasures. We findG′ does a slightly better job predicting empirical fitness measures ofin vivoviral escape time andin vitrospreading rates. While our predictive gain is modest, our model can be modified to test more complex or alternative biological hypotheses. More generally, because of its explicit biological formulation, our model can be easily extended to test for stabilizing vs. diversifying selection. We conjecture that our model could also be extended include epistasis in a more realistic manner than Ising models, while requiring many fewer parameters than Potts models.
Analysis of hierarchical organization in gene expression networks reveals underlying principles of collective tumor cell dissemination and metastatic aggressiveness of inflammatory breast cancer
Authors: Tripathi Shubham , Kumar Jolly Mohit , Woodward Wendy A. , Levine Herbert , Deem Michael W.
Published: October 2017

Background

Clusters of circulating tumor cells (CTCs), despite being rare, may account for more than 95% of metastases. Cells in these clusters do not undergo a complete epithelial-to-mesenchymal transition (EMT) but retain some epithelial traits as compared to individually disseminating tumor cells. Determinants of single cell dissemination versus collective dissemination remain elusive. Inflammatory breast cancer (IBC), a highly aggressive breast cancer subtype that chiefly metastasizes via CTC clusters, is a promising model for studying mechanisms of collective tumor cell dissemination. Previous studies on breast cancer and adult acute myeloid leukemia, motivated by a theory that suggests physical systems with hierarchical organization tend to be more adaptable, have found that the expression of metastasis associated genes is more hierarchically organized in cases of successful metastases.

Methods

We used the cophenetic correlation coefficient (CCC) to quantify the hierarchical organization in the expression networks of two distinct gene sets, collective dissemination associated genes and IBC associated genes, in cancer cell lines and in tumor samples from breast cancer patients. Hypothesizing that a higher CCC for collective dissemination associated genes and for IBC associated genes would be associated with a more evident epithelial phenotype and with worse outcomes in breast cancer patients, we evaluated the correlation of CCC with different phenotypic groups.

Results

The CCC of both gene networks, the collective dissemination associated gene network and the IBC associated gene network, was higher in (a) epithelial cell lines as compared to mesenchymal cell lines and (b) tumor samples from IBC patients, as compared to samples from non-IBC breast cancer patients. A higher CCC of both networks was also correlated with a higher rate of metastatic relapse in breast cancer patients. Neither the levels of CDH1 gene expression, nor gene set enrichment analysis could provide similar insights.

Conclusions

These results suggest that retention of some epithelial traits in disseminating tumor cells as IBC progresses promotes successful breast cancer metastasis to distant organs. The CCC provides additional information regarding the organizational complexity of gene expression in comparison to differential gene expression analyses. We have shown that the CCC may be a useful metric for investigating the collective dissemination phenotype and a prognostic factor for IBC.
Phase contrast imaging of preclinical portal vein embolization with CO2microbubbles
Authors: Tang Rongbiao , Yan Fuhua , Yang Guo-Yuan , Chen Ke-Min
Published: October 2017

Preoperative portal vein embolization (PVE) is employed clinically to avoid postoperative liver insufficiency. Animal models are usually used to study PVE in terms of mechanisms and pathophysiological changes. PVE is formerly monitored by conventional absorption contrast imaging (ACI) with iodine contrast agent. However, the side effects induced by iodine can give rise to animal damage and death. In this study, the feasibility of using phase contrast imaging (PCI) to show PVE using homemade CO2microbubbles in living rats has been investigated. CO2gas was first formed from the reaction between citric acid and sodium bicarbonate. The CO2gas was then encapsulated by egg white to fabricate CO2microbubbles. ACI and PCI of CO2microbubbles were performed and comparedin vitro. An additional increase in contrast was detected in PCI. PCI showed that CO2microbubbles gradually dissolved over time, and the remaining CO2microbubbles became larger. By PCI, the CO2microbubbles were found to have certain stability, suggesting their potential use as embolic agents. CO2microbubbles were injected into the main portal trunk to perform PVE in living rats. PCI exploited the differences in the refractive index and facilitated clear visualization of the PVE after the injection of CO2microbubbles. Findings from this study suggest that homemade CO2microbubbles-based PCI is a novel modality for preclinical PVE research.
Cs3LiZn2(WO4)4 and Rb3Li2Ga(MoO4)4: different filled derivatives of the cation-deficient Cs6Zn5(MoO4)8 structure
Authors: Solodovnikov Sergey F. , Solodovnikova Zoya A. , Zolotova Evgeniya S. , Kadyrova Yulia M. , Savina Aleksandra A. , Stefanovich Sergey Yu. , Khaikina Elena G.
Published: October 2017

Two new compounds, namely cubic tricaesium lithium dizinc tetrakis(tetraoxotungstate), Cs3LiZn2(WO4)4, and tetragonal trirubidium dilithium gallium tetrakis(tetraoxomolybdate), Rb3Li2Ga(MoO4)4, belong to the structural family of Cs6Zn5(MoO4)8 (space group I\overline{4}3d, Z = 4), with a partially incomplete (Zn5/6□1/6) position. In Cs3LiZn2(WO4)4, this position is fully statistically occupied by (Zn2/3Li1/3), and in Rb3Li2Ga(MoO4)4, the 2Li + Ga atoms are completely ordered in two distinct sites of the space group I\overline{4}2d (Z = 4). In the same way, the crystallographically equivalent A
+ cations (A = Cs, Rb) in Cs6Zn5(MoO4)8, Cs3LiZn2(WO4)4 and isostructural A
3LiZn2(MoO4)4 and Cs3LiCo2(MoO4)4 are divided into two sites in Rb3Li2Ga(MoO4)4, as in other isostructural A
3Li2
R(MoO4)4 compounds (AR = TlAl, RbAl, CsAl, CsGa, CsFe). In the title structures, the WO4 and (Zn,Li)O4 or LiO4, GaO4 and MoO4 tetrahedra share corners to form open three-dimensional frameworks with the caesium or rubidium ions occupying cuboctahedral cavities. The tetrahedral frameworks are related to that of mayenite 12CaO·7Al2O3 and isotypic compounds. Comparison of isostructural Cs3
MZn2(MoO4)4 (M = Li, Na, Ag) and Cs6Zn5(MoO4)8 shows a decrease of the cubic lattice parameter and an increase in thermal stability with the filling of the vacancies by Li+ in the Zn position of the Cs6Zn5(MoO4)8 structure, while filling of the cation vacancies by larger Na+ or Ag+ ions plays a destabilizing role. The series A
3Li2
R(MoO4)4 shows second harmonic generation effects compatible with that of β′-Gd2(MoO4)3 and may be considered as nonlinear optical materials with a modest nonlinearity.
Crystallographic studies of cinnamamide derivatives as a means of searching for anticonvulsant activity
Authors: Żesławska Ewa , Nitek Wojciech , Marona Henryk , Gunia-Krzyżak Agnieszka
Published: October 2017

A cinnamamide (3-phenylprop-2-enamide) core is present in many pharmacologically active compounds. We report three new crystal structures of N-substituted cinnamamide derivatives which were screened for anticonvulsant activity, namely (R,S)-(2E)-N-(2-hydroxypropyl)-3-phenylprop-2-enamide, C12H15NO2, (1), (R,S)-(2E)-N-(1-hydroxybutan-2-yl)-3-phenylprop-2-enamide, C13H17NO2, (2), and (2E)-1-(4-hydroxypiperidin-1-yl)-3-phenylprop-2-en-1-one, C14H17NO2, (3). Compounds (1) and (2) crystallize in the Pbca space group with one molecule in the asymmetric unit, whereas compound (3) crystallizes in the P21/c space group with two molecules in the asymmetric unit. All the crystal structures are stabilized by intermolecular O—H...O hydrogen bonds and additionally by N—H...O hydrogen bonds in the structures of (1) and (2). The investigated compounds possess fragments that are considered as beneficial for anticonvulsant activity. The conformations of these compounds were analyzed in comparison with the characteristic features of the proposed pharmacophore model of anticonvulsants active in the maximal electroshock test, i.e. a phenyl ring or other hydrophobic unit, an electron-donor atom and a hydrogen-bond acceptor/donor domain. In the reported series, two calculated distances fitted the reference model, while the third did not. Structure–activity analysis suggests that anticonvulsant properties may be related to the N-atom substituent. It is beneficial to combine an electron-donor atom (e.g. an O atom) with an H atom in the substituent to ensure appropriate interactions with the molecular target. We analyzed the intermolecular interactions in order to find an appropriate spatial arrangement of the important features responsible for anticonvulsant activity.
Synthesis and structures of photoactive rhenium carbonyl complexes derived from 2-(pyridin-2-yl)-1,3-benzothiazole, 2-(quinolin-2-yl)-1,3-benzothiazole and 1,10-phenanthroline
Authors: Pinto Miguel , Chakraborty Indranil , Martinez-Gonzalez Jorge , Mascharak Pradip
Published: October 2017

Carbon monoxide (CO) has recently been identified as a gaseous signaling molecule that exerts various salutary effects in mammalian pathophysiology. Photoactive metal carbonyl complexes (photoCORMs) are ideal exogenous candidates for more controllable and site-specific CO delivery compared to gaseous CO. Along this line, our group has been engaged for the past few years in developing group-7-based photoCORMs towards the efficient eradication of various malignant cells. Moreover, several such complexes can be tracked within cancerous cells by virtue of their luminescence. The inherent luminecscent nature of some photoCORMs and the change in emission wavelength upon CO release also provide a covenient means to track the entry of the prodrug and, in some cases, both the entry and CO release from the prodrug. In continuation of the research circumscribing the development of trackable photoCORMs and also to graft such molecules covalently to conventional delivery vehicles, we report herein the synthesis and structures of three rhenium carbonyl complexes, namely, fac-tricarbonyl[2-(pyridin-2-yl)-1,3-benzothiazole-κ2
N,N′](4-vinylpyridine-κN)rhenium(I) trifluoromethanesulfonate, [Re(C7H7N)(C12H8N2S)(CO)3](CF3SO3), (1), fac-tricarbonyl[2-(quinolin-2-yl)-1,3-benzothiazole-κ2
N,N′](4-vinylpyridine-κN)rhenium(I) trifluoromethanesulfonate, [Re(C7H7N)(C16H10N2S)(CO)3](CF3SO3), (2), and fac-tricarbonyl[1,10-phenanthroline-κ2
N,N′](4-vinylpyridine-κN)rhenium(I) trifluoromethanesulfonate, [Re(C7H7N)(C12H8N2)(CO)3](CF3SO3), (3). In all three complexes, the ReI center resides in a distorted octahedral coordination environment. These complexes exhibit CO release upon exposure to low-power UV light. The apparent CO release rates of the complexes have been measured to assess their comparative CO-donating capacity. The three complexes are highly luminescent and this in turn provides a convenient way to track the entry of the prodrug molecules within biological targets.
The phase problem for two-dimensional crystals. I. Theory
Authors: Arnal Romain D. , Millane Rick P.
Published: October 2017

Properties of the phase problem for two-dimensional crystals are examined. This problem is relevant to protein structure determination using diffraction from two-dimensional crystals that has been proposed using new X-ray free-electron laser sources. The problem is shown to be better determined than for conventional three-dimensional crystallography, but there are still a large number of solutions in the absence of additionala prioriinformation. Molecular envelope information reduces the size of the solution set, and for an envelope that deviates sufficiently from the unit cell a unique solution is possible. The effects of various molecular surface features and incomplete data on uniqueness and prospects forab initiophasing are assessed. Simulations of phase retrieval for two-dimensional crystal data are described in the second paper in this series.
Managing the tensions between exploration and exploitation in large construction projects
Authors: Eriksson Per Erik , Szentes Henrik
Published: October 2017

Purpose

Prior studies highlight the importance of building ambidextrous capabilities to achieve both exploitation of current knowledge and technologies to make profits today, and exploration of new knowledge and technologies to adapt to and prepare for tomorrow’s demands. In spite of its theoretical and practical importance, research on organizational ambidexterity in project-based organizations is scarce. Thus, the purpose of the paper is to study how ambidexterity may be managed and how exploration and exploitation may be achieved in construction projects. The research identifies some drivers and barriers to exploration and exploitation and also sheds light on how various management approaches interact and affect exploration and exploitation activities.

Design/methodology/approach

The empirical material is drawn from 40 semi-structured interviews with managers representing the client, the contractor and the designer involved in each of the seven large construction projects in the sample.

Findings

In contrast to prior literature in high-tech industries where exploitation focuses on continuous development, exploitation in construction projects often involves adopting conventional methods and solutions based on existing knowledge without any development efforts at all. This may enhance short-term efficiency and lower risk at the project level but increase risk at the firm level. Tight time schedules hinder both radical innovations and incremental developments, and the findings also reveal that to invest in efforts on explorative solutions, it must be possible to exploit the solutions in the same project.

Research limitations/implications

In this empirical context, the traditional structural and sequential ambidexterity solutions are not sufficient. In construction projects, contextual ambidexterity solutions in which key project actors collaborate in developing systemic innovations and fine-tuning solutions across projects are more effective.

Practical implications

Sufficient project size and/or long-term contracts over a series of projects enhance both investments in explorative activities and exploitation through continuous developments from project to project. In design–bid–build contracts, the client and consultant often miss opportunities to explore new technical solutions that rely on contractor competencies. Early procurement of contractors (e.g. in collaborative design–build contracts) thereby enables the achievement of both exploration and exploitation.

Originality/value

This study provides important input to the authors’ understanding of how exploration and exploitation may be managed in project-based industries, which has been scarcely studied in previous ambidexterity literature.
Human resource management practices and organizational commitment: research methods, issues and future directions (2001-2016)
Authors: Srirangam Ramaprasad Badrinarayan , Prabhu K.P. Nandan , Lakshminarayanan Sethumadhavan , Pai Yogesh P.
Published: October 2017

Purpose

The purpose of this paper is to outline the various research methods adopted by researchers in studies that have investigated the relationship between human resource management (HRM) practices and organizational commitment (OC).

Design/methodology/approach

The authors adopted a comprehensive review that covers empirical research on HRM-OC relationship, which was published between 2001 and 2016 in international peer-reviewed journals. A total of 63 empirical studies were included in this review. Authors adopted content analysis to synthesize the findings on the adopted research methods.

Findings

This review clearly indicates the excessive reliance of researchers on specific research methods (i.e. surveys, individual-level analysis, and cross-sectional design). However, there is a steady increase in empirical studies that have adopted mixed-method, multi-actor, and multi-level research designs.

Originality/value

This review has attempted to explore advanced research methods that may offer assistance to overcome methodological limitations of the current HRM-OC literature.
Pro-poor adaptation for the urban extreme poor in the context of climate change
Authors: Hossain Md. Zakir , Rahman Md. Ashiq Ur
Published: October 2017

Purpose

The purpose of this paper is to examine pro-poor urban asset adaptation to climate variability and change. It constructs a conceptual framework that explores the appropriate asset adaptation strategies for extreme poor households as well as the process of supporting these households and groups in accumulating these assets.

Design/methodology/approach

Qualitative data are obtained from life histories, key informant interviews (KIIs) and focus-group discussions (FGDs). These data are collected, coded and themed.

Findings

This research identifies that households among the urban extreme poor do their best to adapt to perceived climate changes; however, in the absence of savings, and access to credit and insurance, they are forced to adopt adverse coping strategies. Individual adaptation practices yield minimal results and are short lived and even harmful because the urban extreme poor are excluded from formal policies and institutions as they lack formal rights and entitlements. For the poorest, the process of facilitating and maintaining patron–client relationships is a central coping strategy. Social policy approaches are found to be effective in facilitating asset adaptation for the urban extreme poor because they contribute to greater resilience to climate change.

Originality/value

This study analyses the empirical evidence through the lens of a pro-poor asset-adaptation framework. It shows that the asset-transfer approach is an effective in building household-adaptation strategies. Equally important is the capacity to participate in and influence the institutions from which these people have previously been excluded.
Social enterprise and corporate social responsibility
Authors: Palakshappa Nitha , Grant Suzanne
Published: October 2017

Purpose

The purpose of this paper is to explore the concepts of social enterprise (SE) and corporate social responsibility (CSR). Both terms are regarded as pivotal but somewhat related when discussed in scholarship. Despite this few attempts have been made to isolate the manner in which they connect.

Design/methodology/approach

In this paper the authors attempt to unpack these two terms in order to isolate key areas of overlap in their use and operationalization. In doing so, the authors address the call for work to synthesize the highly fragmented literature.

Findings

The paper demonstrates that, while SE and CSR retain a unique place in the business-society landscape, there is indeed an overlap between the two. The generation of value – social, collaborative, or strategic – appears to be a central theme that connects the two concepts.

Originality/value

The authors offer a detailed discussion of how SE and CSR have contributed to scholarship, and demonstrate that the two terms are indeed interrelated on many levels.
Female entrepreneurship in Africa
Authors: Nziku Dina Modestus , Struthers John Joseph
Published: October 2017

Purpose

The purpose of this paper is to develop a conceptual framework which combines the strength of weak ties (SWT) concept with an innovative taxonomy for mitigating principal-agent (P-A) conflicts. The taxonomy highlights the mechanisms through which African women can overcome the obstacles faced when setting up businesses.

Design/methodology/approach

The paper discusses the role of “weak ties” networks in entrepreneurial activities and integrates the concept with the key parameters of the P-A paradigm. The aim is to develop a taxonomy (or scorecard) for mitigating the challenges faced by women entrepreneurs in Africa from a P-A perspective. Six P-A parameters are analysed, namely, attitudes towards risk; behaviour-based vs targets-based contracts; asymmetric information; risk-sharing; transaction costs; and verification and monitoring costs.

Findings

With the aid of the taxonomy developed in the paper, the authors analyse the channels through which “SWT” networks may impact in mitigating the problems arising from the P-A paradigm. Some implications for women entrepreneurs in Africa are highlighted.

Research limitations/implications

The current conceptual study suggests that the “SWT” concept can be used by African women entrepreneurs to mitigate P-A problems. The authors argue that the original P-A taxonomy developed in the paper fills a conceptual research gap in the existing literature. Embedding the SWT concept within a P-A framework will facilitate further research not only to understand African women entrepreneurs’ attitudes (and responses) towards risk and uncertainty, but this will also facilitate greater understanding of the importance women attach to the role of incentives within their businesses.

Practical implications

The taxonomy presents new insights for understanding the most serious constraints that hinder women entrepreneurs in Africa. The taxonomy will be the basis for a follow-up empirical paper on selected African countries.

Originality/value

The originality of this study lies in the development of an innovative taxonomy which highlights the role of “SWT” social networks towards mitigating the P-A problem among African women entrepreneurs. The paper makes a significant contribution to the literature from a conceptual perspective.