bluuebunny/crossref_metadata_2025 huggingface dataset:
Neuropsychological Profile of a Girl with Wiskott-Aldrich Syndrome
Authors: Byrne Andrea M. , Schechter Tal , Westmacott Robyn
Published: March 2018

We report the neuropsychological profile of a 6-year-old girl with Wiskott-Aldrich syndrome, a rare X-linked immunodeficiency disorder associated with thrombocytopenia, eczema, recurrent infections, and malignancy. Wiskott-Aldrich syndrome occurs almost exclusively in males and is extremely rare in females, with no known research focused on cognitive and academic functioning in this population. Our patient was referred due to concerns about her memory and academic functioning. She had a history of progressive thrombocytopenia and hematopoietic stem cell transplantation at age 15 months. Standardized measures of intellectual ability, language, visual-spatial and visual-motor skills, attention, memory, and academic achievement were administered. The results showed average to above-average performance in multiple areas of cognitive and academic functioning, with weaknesses in phonological awareness and rapid naming. The advent of hematopoietic stem cell transplantation has led to considerable improvement in the long-term prognosis of children with Wiskott-Aldrich syndrome. Although the impact of this syndrome and related conditions on neurocognitive development is presently unknown, this case highlights both the importance of considering base rates for commonly occurring conditions and the significant role neuropsychology can play in identifying cognitive strengths and weaknesses in the context of the developing brain.
Implicit Behavioral Change in Response to Cognitive Tasks in Alzheimer Disease
Authors: Bomilcar Iris , Morris Robin G. , Brown Richard G. , Mograbi Daniel C.
Published: March 2018

Background and Objective:

Lack of awareness about impairments is commonly found in Alzheimer disease (AD), but recent evidence suggests that patients may respond to the experience of illness despite limited awareness. In this study, we explored whether implicit emotional responses to experiences of failure in cognitive tasks would result in longer-term change in behavior.

Methods:

Twenty-two patients with AD were seen 1 week after a previous session in which they performed computer tasks that had been manipulated to be either too difficult (failure condition) or very easy (success condition) for them. At the second session, both types of tasks were set to have medium difficulty and were administered so that the participants decided how long to persist on each task. Task persistence was determined by relative time spent doing the tasks, considering that participants would be more likely to stop performing tasks in which they had experienced failure during the first session.

Results:

Task persistence in the second session was not affected by performance in the first session. However, when participants’ awareness of performance in the first session was taken into account, differences were found in persistence between tasks in the second session. During the second session, participants stopped performing tasks after a sequence of errors. There were no self-reported changes in motivation or enjoyment in response to task failure.

Conclusions:

These findings suggest that implicit learning of task valence may be compromised in AD, but that initial moments of awareness of performance may influence long-term adaptation in unaware patients.
Harry Smith. 19 September 1935—9 February 2015
Authors: Grierson Donald
Published: March 2018

Harry Smith was a botanist with a driving passion to understand how plant growth, development and responses to the environment are regulated. He was a true experimentalist with a restless mind, a determination to question and the commitment to follow through. Harry valued achievement over background, and his research combined biochemical, molecular and physiological approaches aimed at understanding the behaviour of plants in the real world. This led him to a series of classical experiments, begun at the University of Nottingham and continued at the University of Leicester, studying how plants detect proximity and shading by other plants. This work transformed our understanding of the role of the red/far-red light-absorbing phytochrome pigments in the perception of and response to vegetative shading. Harry defined the mechanism of the shade avoidance syndrome, and this work, taught to students worldwide, is of fundamental importance in understanding plant behaviour in the natural environment and agriculture. Harry was a truly inspirational teacher, research leader and head of department, and also a visionary founder and editor of successful journals such as
Plant, Cell and Environment
,
Molecular Ecology
and
Global Change Biology
, as well as being a veteran gardener, tree planter, artist and car lover.
A Bayesian phylogenetic study of the Dravidian language family
Authors: Kolipakam Vishnupriya , Jordan Fiona M. , Dunn Michael , Greenhill Simon J. , Bouckaert Remco , Gray Russell D. , Verkerk Annemarie
Published: March 2018

The Dravidian language family consists of about 80 varieties (Hammarström H. 2016Glottolog 2.7) spoken by 220 million people across southern and central India and surrounding countries (Steever SB. 1998 InThe Dravidian languages(ed. SB Steever), pp. 1–39: 1). Neither the geographical origin of the Dravidian language homeland nor its exact dispersal through time are known. The history of these languages is crucial for understanding prehistory in Eurasia, because despite their current restricted range, these languages played a significant role in influencing other language groups including Indo-Aryan (Indo-European) and Munda (Austroasiatic) speakers. Here, we report the results of a Bayesian phylogenetic analysis of cognate-coded lexical data, elicited first hand from native speakers, to investigate the subgrouping of the Dravidian language family, and provide dates for the major points of diversification. Our results indicate that the Dravidian language family is approximately 4500 years old, a finding that corresponds well with earlier linguistic and archaeological studies. The main branches of the Dravidian language family (North, Central, South I, South II) are recovered, although the placement of languages within these main branches diverges from previous classifications. We find considerable uncertainty with regard to the relationships between the main branches.
Synthesis and characterization of dextran-coated iron oxide nanoparticles
Authors: Predescu Andra Mihaela , Matei Ecaterina , Berbecaru Andrei Constantin , Pantilimon Cristian , Drăgan Claudia , Vidu Ruxandra , Predescu Cristian , Kuncser Victor
Published: March 2018

Synthesis and characterization of iron oxide nanoparticles coated with a large molar weight dextran for environmental applications are reported. The first experiments involved the synthesis of iron oxide nanoparticles which were coated with dextran at different concentrations. The synthesis was performed by a co-precipitation technique, while the coating of iron oxide nanoparticles was carried out in solution. The obtained nanoparticles were characterized by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction spectrometry, Fourier transform infrared spectroscopy and superconducting quantum interference device magnetometry. The results demonstrated a successful coating of iron oxide nanoparticles with large molar weight dextran, of which agglomeration tendency depended on the amount of dextran in the coating solution. SEM and TEM observations have shown that the iron oxide nanoparticles are of about 7 nm in size.
Nanostructured polyurethane perylene bisimide ester assemblies with tuneable morphology and enhanced stability
Authors: Zhang Xiaoxiao , Gong Tingyuan , Chi Hong , Li Tianduo
Published: March 2018

Size control has been successfully achieved in inorganic materials, but it remains a challenge in polymer nanomaterials due to their polydispersity. Here, we report a facile approach to tailor the diameters of polyurethane (PU) nanoparticles (490 nm, 820 nm and 2.1 µm) via perylene bisimide (PBI) assisted self-assembly. The formed morphologies such as spindle, spherical and core–shell structures depend on the ratio of PBI and polymer concentrations. It is shown that the formation of PU nanoparticles is directed by π–π stacking of PBI and the morphology transition is not only affected by the amount of PBI incorporated, but also influenced by solvent, which controls the initial evaporation balance. Furthermore, the prepared PUs exhibit retained optical stability and enhanced thermal stability. The PUs, designed to have conjugated PBI segments in backbones, were synthesized via ring-opening and condensation reactions. Compared with the neat PU, gel permeation chromatography shows narrower molecular weight distribution. Fluorescence spectra and ultraviolet–visible spectra indicate retained maximum emission wavelength of PBI at 574 nm and 5.2% quantum yields. Thermo-gravimetric analysis and differential scanning calorimetry reveal 79°C higher decomposition temperature and 22°C higher glass transition temperature. This study provides a new way to fabricate well-defined nanostructures of functionalized PUs.
Do an invasive organism's dispersal characteristics affect how we should search for it?
Authors: Triska Maggie D. , Renton Michael
Published: March 2018

We investigated how an invading organism's dispersal characteristics affect the efficacy of different surveillance strategies aimed at detecting that organism as it spreads following a new incursion. Specifically, we assessed whether, out of the surveillance strategies tested, the best surveillance strategy for an organism varied depending on the way it disperses. We simulated the spread of invasive organisms with different dispersal characteristics including leptokurtic and non-leptokurtic kernels with different median dispersal distances and degrees of kurtosis. We evaluated surveillance strategies with different sampling arrangements, densities and frequencies. Surveillance outcomes compared included the time to detection, the total spread of the invasion and the likelihood of the invasion reaching new areas. Overall, dispersal characteristics affected the surveillance outcomes, but the grid surveillance arrangement consistently performed best in terms of early detection and reduced spread within and between fields. Additionally, the results suggest that dispersal characteristics may influence spread to new areas and surveillance strategies. Therefore, knowledge on an invasive organism's dispersal characteristics may influence how we search for it and how we manage the invasion to prevent spread to new areas.
Non-invasive paper-based microfluidic device for ultra-low detection of urea through enzyme catalysis
Authors: Suresh Vignesh , Qunya Ong , Kanta Bera Lakshmi , Yuh Lee Yeong , Chong Karen S. L.
Published: March 2018

This work describes the design, fabrication and characterization of a paper-based microfluidic device for ultra-low detection of urea through enzyme catalysis. The microfluidic system comprises an entry port, a fluidic channel, a reaction zone and two electrodes (contacts). Wax printing was used to create fluidic channels on the surface of a chromatography paper. Pre-conceptualized designs of the fluidic channel are wax-printed on the paper substrate while the electrodes are screen-printed. The paper printed with wax is heated to cause the wax reflow along the thickness of the paper that selectively creates hydrophilic and hydrophobic zones inside the paper. Urease immobilized in the reaction zone catalyses urea into releasing ions and, thereby, generating a current flow between the electrodes. A measure of current with respect to time at a fixed potential enables the detection of urea. The methodology enabled urea concentration down to 1 pM to be detected. The significance of this work lies in the use of simple and inexpensive paper-based substrates to achieve detection of ultra-low concentrations of analytes such as urea. The process is non-invasive and employs a less cumbersome two-electrode assembly.
Experiments and modelling of rate-dependent transition delay in a stochastic subcritical bifurcation
Authors: Bonciolini Giacomo , Ebi Dominik , Boujo Edouard , Noiray Nicolas
Published: March 2018

Complex systems exhibiting critical transitions when one of their governing parameters varies are ubiquitous in nature and in engineering applications. Despite a vast literature focusing on this topic, there are few studies dealing with the effect of the rate of change of the bifurcation parameter on the tipping points. In this work, we consider a subcritical stochastic Hopf bifurcation under two scenarios: the bifurcation parameter is first changed in a quasi-steady manner and then, with a finite ramping rate. In the latter case, a rate-dependent bifurcation delay is observed and exemplified experimentally using a thermoacoustic instability in a combustion chamber. This delay increases with the rate of change. This leads to a state transition of larger amplitude compared with the one that would be experienced by the system with a quasi-steady change of the parameter. We also bring experimental evidence of a dynamic hysteresis caused by the bifurcation delay when the parameter is ramped back. A surrogate model is derived in order to predict the statistic of these delays and to scrutinize the underlying stochastic dynamics. Our study highlights the dramatic influence of a finite rate of change of bifurcation parameters upon tipping points, and it pinpoints the crucial need of considering this effect when investigating critical transitions.
Division rate, cell size and proteome allocation: impact on gene expression noise and implications for the dynamics of genetic circuits
Authors: Bertaux François , Marguerat Samuel , Shahrezaei Vahid
Published: March 2018

The cell division rate, size and gene expression programmes change in response to external conditions. These global changes impact on average concentrations of biomolecule and their variability or noise. Gene expression is inherently stochastic, and noise levels of individual proteins depend on synthesis and degradation rates as well as on cell-cycle dynamics. We have modelled stochastic gene expression inside growing and dividing cells to study the effect of division rates on noise in mRNA and protein expression. We use assumptions and parameters relevant to
Escherichia coli
, for which abundant quantitative data are available. We find that coupling of transcription, but not translation rates to the rate of cell division can result in protein concentration and noise homeostasis across conditions. Interestingly, we find that the increased cell size at fast division rates, observed in
E. coli
and other unicellular organisms, buffers noise levels even for proteins with decreased expression at faster growth. We then investigate the functional importance of these regulations using gene regulatory networks that exhibit bi-stability and oscillations. We find that network topology affects robustness to changes in division rate in complex and unexpected ways. In particular, a simple model of persistence, based on global physiological feedback, predicts increased proportion of persister cells at slow division rates. Altogether, our study reveals how cell size regulation in response to cell division rate could help controlling gene expression noise. It also highlights that understanding circuits' robustness across growth conditions is key for the effective design of synthetic biological systems.
Evaluation and mechanism of ammonia nitrogen removal using sediments from a malodorous river
Authors: Chen Xing , Jiang Xia , Huang Wei
Published: March 2018

Malodorous rivers are among the major environmental problems of cities in developing countries. In addition to the unpleasant smell, the sediments of such rivers can act as a sink for pollutants. The excessive amount of ammonia nitrogen (NH
3
−N) in rivers is the main factor that causes the malodour. Therefore, a suitable method is necessary for sediment disposition and NH
3
−N removal in malodorous rivers. The sediment in a malodorous river (PS) in Beijing, China was selected and modified via calcination (PS-D), Na
+
doping (PS-Na) and calcination–Na
+
doping (PS-DNa). The NH
3
−N removal efficiency using the four sediment materials was evaluated, and results indicated that the NH
3
−N removal efficiency using the modified sediment materials could reach over 60%. PS-DNa achieved the highest NH
3
−N removal efficiency (90.04%). The kinetics study showed that the pseudo-second-order model could effectively describe the sorption kinetics and that the exterior activated site had the main function of P sorption. The results of the sorption isotherms indicated that the maximum sorption capacities of PS-Na, PS-D and PS-DNa were 0.343, 0.831 and 1.113 mg g
−1
, respectively, and a high temperature was favourable to sorption. The calculated thermodynamic parameters suggested that sorption was a feasible or spontaneous (Δ
G
 < 0), entropy-driven (Δ
S
 > 0), and endothermic (Δ
H
 > 0) reaction.
Increasing cell–device adherence using cultured insect cells for receptor-based biosensors
Authors: Terutsuki Daigo , Mitsuno Hidefumi , Sakurai Takeshi , Okamoto Yuki , Tixier-Mita Agnès , Toshiyoshi Hiroshi , Mita Yoshio , Kanzaki Ryohei
Published: March 2018

Field-effect transistor (FET)-based biosensors have a wide range of applications, and a bio-FET odorant sensor, based on insect (Sf21) cells expressing insect odorant receptors (ORs) with sensitivity and selectivity, has emerged. To fully realize the practical application of bio-FET odorant sensors, knowledge of the cell–device interface for efficient signal transfer, and a reliable and low-cost measurement system using the commercial complementary metal-oxide semiconductor (CMOS) foundry process, will be indispensable. However, the interfaces between Sf21 cells and sensor devices are largely unknown, and electrode materials used in the commercial CMOS foundry process are generally limited to aluminium, which is reportedly toxic to cells. In this study, we investigated Sf21 cell–device interfaces by developing cross-sectional specimens. Calcium imaging of Sf21 cells expressing insect ORs was used to verify the functions of Sf21 cells as odorant sensor elements on the electrode materials. We found that the cell–device interface was approximately 10 nm wide on average, suggesting that the adhesion mechanism of Sf21 cells may differ from that of other cells. These results will help to construct accurate signal detection from expressed insect ORs using FETs.
An objectivein vivodiagnostic method for inflammatory bowel disease
Authors: Payne Sophie C. , Shepherd Robert K. , Sedo Alicia , Fallon James B. , Furness John B.
Published: March 2018

Inflammatory damage to the bowel, as occurs in inflammatory bowel disease (IBD), is debilitating to patients. In both patients and animal experimental models, histological analyses of biopsies and endoscopic examinations are used to evaluate the disease state. However, such measurements often have delays and are invasive, while endoscopy is not quantitatively objective. Therefore, a real-time quantitative method to assess compromised mucosal barrier function is advantageous. We investigated the correlation ofin vivochanges in electrical transmural impedance with histological measures of inflammation. Four platinum (Pt) ball electrodes were placed in the lumen of the rat small intestine, with a return electrode under the skin. Electrodes placed within the non-inflamed intestine generated stable impedances during the 3 h testing period. Following an intraluminal injection of 2,4,6-trinitrobenzene sulfonic acid (TNBS), an established animal model of IBD, impedances in the inflamed region significantly decreased relative to a region not exposed to TNBS (p < 0.05). Changes in intestinal transmural impedance were correlated (p < 0.05) with histologically assessed damage to the mucosa and increases in neutrophil, eosinophil and T-cell populations at 3 h compared with tissue from control regions. This quantitative, real-time assay may have application in the diagnosis and clinical management of IBD.
A hydrostatic model of the Wirtz pump
Authors: Deane Jonathan H. B. , Bevan Jonathan J.
Published: March 2018

The Wirtz pump is not only an excellent example of alternative technology, using as it does the kinetic energy of a stream to raise a proportion of its water, but its mathematical modelling also poses several intriguing problems. We give some history of the Wirtz pump and describe its operation. Taking a novel dynamical systems approach, we then derive a discrete mathematical model in the form of a mapping that describes its hydrostatic behaviour. Our model enables us to explain several aspects of the behaviour of the pump as well as to design one that gives approximately maximal, and maximally constant, output pressure.
Effect of elevated CO2and small boat noise on the kinematics of predator–prey interactions
Authors: McCormick Mark I. , Watson Sue-Ann , Simpson Stephen D. , Allan Bridie J. M.
Published: March 2018

Oceans of the future are predicted to be more acidic and noisier, particularly along the productive coastal fringe. This study examined the independent and combined effects of short-term exposure to elevated CO2and boat noise on the predator–prey interactions of a pair of common coral reef fishes (Pomacentrus wardiand its predator,Pseudochromis fuscus). Successful capture of prey by predators was the same regardless of whether the pairs had been exposed to ambient control conditions, the addition of either playback of boat noise, elevated CO2(925 µatm) or both stressors simultaneously. The kinematics of the interaction were the same for all stressor combinations and differed from the controls. The effects of CO2or boat noise were the same, suggesting that their effects were substitutive in this situation. Prey reduced their perception of threat under both stressors individually and when combined, and this coincided with reduced predator attack distances and attack speeds. The lack of an additive or multiplicative effect when both stressors co-occurred was notable given the different mechanisms involved in sensory disruptions and highlights the importance of determining the combined effects of key drivers to aid in predicting community dynamics under future environmental scenarios.
A direct glia-to-neuron natural transdifferentiation ensures nimble sensory-motor coordination of male mating behaviour
Authors: Molina-García Laura , Cook Steven J. , Kim Byunghyuk , Bonnington Rachel , Sammut Michele , O’Shea Jack , Elliott David J. , Hall David H. , Emmons Scott W. , Barrios Arantza , Poole Richard J.
Published: March 2018

The coordinated execution of innate, stereotyped sexual behaviours, such as courtship and mating, requires sexually dimorphic sensory-motor circuits that are genetically specified during development (reviewed in [1-3]). Studies in the nematodeCaenorhabditis elegans, in which the development and function of neural circuits can be interrogated with single cell resolution, have revealed two general developmental mechanisms underlying sexual dimorphism in the nervous system. The first involves the acquisition of sexually dimorphic features in sex-shared neurons during sexual maturation, which include changes in terminal gene expression, such as odorant receptors, neurotransmitters and synaptic regulators [4-10]. The second mechanism involves the generation of sex-specific neurons [11-13]. This requires sex-specific cell death [14]or neurogenesis events resulting from extensive sex differences in the cell division patterns and neurodevelopmental programmes of post-embryonic cell lineages (reviewed in [3]). Here we identify a third, novel way to generate sexual dimorphism in the nervous system. We find that during sexual maturation (L4 stage), a class of sex-shared glial cells acquires sexually dimorphic function by undergoing a direct glia-to-neuron transdifferentiation that results in the production of male-specific neurons. This plasticity is regulated cell-intrinsically by the sex-determination pathway. These previously unnoticed neurons, which we term PHDs, are putative proprioceptors that regulate male locomotion during specific steps of mating. One of these steps is a novel readjustment movement performed when intromission becomes difficult to achieve. Our results reveal sex-specific direct transdifferentiation as a novel mechanism for generating sex-specific neurons and also show the importance of proprioceptive feedback during the complex steps of mating for successful reproduction.
Medial orbitofrontal cortex, dorsolateral prefrontal cortex, and hippocampus differentially represent the event saliency
Authors: Jafarpour Anna , Griffin Sandon , Lin Jack J. , Knight Robert T.
Published: March 2018

Two primary functions attributed to the hippocampus and prefrontal cortex network are retaining the temporal and spatial associations of events and detecting deviant events. It is, however, unclear how these two functions converge onto one mechanism. Here, we tested whether increased activity with perceiving salient events is a deviant detection signal or contains information about the event associations by reflecting the magnitude of deviance (i.e., event saliency). We also tested how the deviant detection signal is affected by the degree of anticipation. We studied regional neural activity when people watched a movie that had varying saliency of a novel or an anticipated flow of salient events. Using intracranial electroencephalography from ten patients, we observed that high-frequency activity (50-150 Hz) in the hippocampus, dorsolateral prefrontal cortex (dorsolateral PFC), and medial orbitofrontal cortex (OFC) tracked event saliency. We also observed that medial OFC activity was stronger when the salient events were anticipated than when they were novel. These results suggest that dorsolateral PFC and medial OFC, as well as the hippocampus, signify the saliency magnitude of events, reflecting the hierarchical structure of event associations.
Recovering signals of ghost archaic introgression in African populations
Authors: Durvasula Arun , Sankararaman Sriram
Published: March 2018

While introgression from Neanderthals and Denisovans has been well-documented in modern humans outside Africa, the contribution of archaic hominins to the genetic variation of present-day Africans remains poorly understood. Using 405 whole-genome sequences from four sub-Saharan African populations, we provide complementary lines of evidence for archaic introgression into these populations. Our analyses of site frequency spectra indicate that these populations derive 2-19% of their genetic ancestry from an archaic population that diverged prior to the split of Neanderthals and modern humans. Using a method that can identify segments of archaic ancestry without the need for reference archaic genomes, we built genome-wide maps of archaic ancestry in the Yoruba and the Mende populations that recover about 482 and 502 megabases of archaic sequence, respectively. Analyses of these maps reveal segments of archaic ancestry at high frequency in these populations that represent potential targets of adaptive introgression. Our results reveal the substantial contribution of archaic ancestry in shaping the gene pool of present-day African populations.

One sentence summary

Multiple present-day African populations inherited genes from an unknown archaic population that diverged before modern humans and Neanderthals split.
Integrative cross-species analyses identify deficits in habituation learning as a widely affected mechanism in Autism
Authors: Fenckova Michaela , Asztalos Lenke , Cizek Pavel , Singgih Euginia L. , Blok Laura E.R. , Glennon Jeffrey C. , IntHout Joanna , Zweier Christiane , Eichler Evan E. , Bernier Raphael A. , Asztalos Zoltan , Schenck Annette
Published: March 2018

Background

Although habituation is one of the most ancient and fundamental forms of learning, its regulators and relevance for human disease are poorly understood.

Methods

We manipulated the orthologs of 286 genes implicated in intellectual disability (ID) with or without comorbid autism spectrum disorder (ASD) specifically in Drosophila neurons, and tested these models in light-off jump habituation. We dissected neuronal substrates underlying the identified habituation deficits and integrated genotype-phenotype annotations, gene ontologies and interaction networks to determine the clinical features and molecular processes that are associated with habituation deficits.

Results

We identified more than 100 genes required for habituation learning. For the vast majority of these, 93 genes, a role in habituation learning was previously unknown. These genes characterize ID disorders with overgrowth/macrocephaly and comorbid ASD. Moreover, ASD individuals from the Simons Simplex Collection carrying disruptive de novo mutations in these genes exhibit increased rates of specific aberrant behaviors including stereotypic speech, hyperactivity and irritability. At the molecular level, ID genes required for normal habituation are enriched in synaptic function and converge on Ras-MAPK signaling. Both increased Ras-MAPK signaling in GABAergic and decreased Ras-MAPK signaling in cholinergic neurons specifically inhibit the adaptive habituation response.

Conclusions

Our work demonstrates the relevance of habituation learning to autism, identifies an unprecedented number of novel habituation players, supports an emerging role for inhibitory neurons in habituation and reveals an opposing, circuit-level-based mechanism for Ras-MAPK signaling. This establishes habituation as a possible, widely applicable target for pharmacologic intervention in ID/ASD.
Machine learning reveals missing edges and putative interaction mechanisms in microbial ecosystem networks
Authors: DiMucci Demetrius , Kon Mark , Segrè Daniel
Published: March 2018

Microbes affect each other’s growth in multiple, often elusive ways. The ensuing interdependencies form complex networks, believed to influence taxonomic composition, as well as community-level functional properties and dynamics. Elucidation of these networks is often pursued by measuring pairwise interaction in co-culture experiments. However, combinatorial complexity precludes the exhaustive experimental analysis of pairwise interactions even for moderately sized microbial communities. Here, we use a machine-learning random forest approach to address this challenge. In particular, we show how partial knowledge of a microbial interaction network, combined with trait-level representations of individual microbial species, can provide accurate inference of missing edges in the network and putative mechanisms underlying interactions. We applied our algorithm to two case studies: an experimentally mapped network of interactions between auxotrophic E. coli strains, and a large in silico network of metabolic interdependencies between 100 human gut-associated bacteria. For this last case, 5% of the network is enough to predict the remaining 95% with 80% accuracy, and mechanistic hypotheses produced by the algorithm accurately reflect known metabolic exchanges. Our approach, broadly applicable to any microbial or other ecological network, can drive the discovery of new interactions and new molecular mechanisms, both for therapeutic interventions involving natural communities and for the rational design of synthetic consortia.

Importance

Different organisms in a microbial community may drastically affect each other’s growth phenotype, significantly affecting the community dynamics, with important implications for human and environmental health. Novel culturing methods and decreasing costs of sequencing will gradually enable high-throughput measurements of pairwise interactions in systematic co-culturing studies. However, a thorough characterization of all interactions that occur within a microbial community is greatly limited both by the combinatorial complexity of possible assortments, and by the limited biological insight that interaction measurements typically provide without laborious specific follow-ups. Here we show how a simple and flexible formal representation of microbial pairs can be used for classification of interactions with machine learning. The approach we propose predicts with high accuracy the outcome of yet to be performed experiments, and generates testable hypotheses about the mechanisms of specific interactions.
Dendrite regeneration of adult Drosophila sensory neurons diminishes with aging and is inhibited by epidermal-derived matrix metalloproteinase 2
Authors: DeVault Laura , Li Tun , Izabel Sarah , Thompson-Peer Katherine L. , Jan Lily Yeh , Jan Yuh Nung
Published: March 2018

Dendrites possess distinct structural and functional properties that enable neurons to receive information from the environment as well as other neurons. Despite their key role in neuronal function, current understanding of the ability of neurons to regenerate dendrites is lacking. This study characterizes the structural and functional capacity for dendrite regeneration in vivo in adult animals and examines the effect of neuronal maturation on dendrite regeneration. We focused on the class IV dendritic arborization (c4da) neuron of the Drosophila sensory system, which has a dendritic arbor that undergoes dramatic remodeling during the first 3 d of adult life and then maintains a relatively stable morphology thereafter. Using a laser severing paradigm, we monitored regeneration after acute and spatially restricted injury. We found that the capacity for regeneration was present in adult neurons but diminished as the animal aged. Regenerated dendrites recovered receptive function. Furthermore, we found that the regenerated dendrites show preferential alignment with the extracellular matrix (ECM). Finally, inhibition of ECM degradation by inhibition of matrix metalloproteinase 2 (Mmp2) to preserve the extracellular environment characteristics of young adults led to increased dendrite regeneration. These results demonstrate that dendrites retain regenerative potential throughout adulthood and that regenerative capacity decreases with aging.
Stem cell niche-specific Ebf3 maintains the bone marrow cavity
Authors: Seike Masanari , Omatsu Yoshiki , Watanabe Hitomi , Kondoh Gen , Nagasawa Takashi
Published: March 2018

Bone marrow is the tissue filling the space between bone surfaces. Hematopoietic stem cells (HSCs) are maintained by special microenvironments known as niches within bone marrow cavities. Mesenchymal cells, termed CXC chemokine ligand 12 (CXCL12)-abundant reticular (CAR) cells or leptin receptor-positive (LepR+) cells, are a major cellular component of HSC niches that gives rise to osteoblasts in bone marrow. However, it remains unclear how osteogenesis is prevented in most CAR/LepR+ cells to maintain HSC niches and marrow cavities. Here, using lineage tracing, we found that the transcription factor early B-cell factor 3 (Ebf3) is preferentially expressed in CAR/LepR+ cells and that Ebf3-expressing cells are self-renewing mesenchymal stem cells in adult marrow. When Ebf3 is deleted in CAR/LepR+ cells, HSC niche function is severely impaired, and bone marrow is osteosclerotic with increased bone in aged mice. In mice lacking Ebf1 and Ebf3, CAR/LepR+ cells exhibiting a normal morphology are abundantly present, but their niche function is markedly impaired with depleted HSCs in infant marrow. Subsequently, the mutants become progressively more osteosclerotic, leading to the complete occlusion of marrow cavities in early adulthood. CAR/LepR+ cells differentiate into bone-producing cells with reduced HSC niche factor expression in the absence of Ebf1/Ebf3. Thus, HSC cellular niches express Ebf3 that is required to create HSC niches, to inhibit their osteoblast differentiation, and to maintain spaces for HSCs.
Structural and functional analysis of the DOT1L–AF10 complex reveals mechanistic insights into MLL-AF10-associated leukemogenesis
Authors: Zhang Heng , Zhou Bo , Qin Su , Xu Jing , Harding Rachel , Tempel Wolfram , Nayak Vinod , Li Yanjun , Loppnau Peter , Dou Yali , Min Jinrong
Published: March 2018

The mixed-lineage leukemia (MLL)-AF10 fusion oncoprotein recruits DOT1L to the homeobox A (HOXA) gene cluster through its octapeptide motif leucine zipper (OM-LZ), thereby inducing and maintaining the MLL-AF10-associated leukemogenesis. However, the recognition mechanism between DOT1L and MLL-AF10 is unclear. Here, we present the crystal structures of both apo AF10OM-LZ and its complex with the coiled-coil domain of DOT1L. Disruption of the DOT1L–AF10 interface abrogates MLL-AF10-associated leukemic transformation. We further show that zinc stabilizes the DOT1L–AF10 complex and may be involved in the regulation of the HOXA gene expression. Our studies may also pave the way for the rational design of therapeutic drugs against MLL-rearranged leukemia.
Crystallographic patterns in Philippine indigenous textiles
Authors: De Las Peñas Ma. Louise Antonette N. , Garciano Agnes , Verzosa Debbie Marie , Taganap Eduard
Published: March 2018

The aim of this study was to analyze a representative sample of Philippine indigenous textiles in order to capture the range of symmetries and color symmetries present. This paper examines the existence of symmetries in finite designs, and classifies the plane-group and frieze-group symmetry types of the repeated patterns in woven textiles. The tendency of a particular symmetry to be more or less common than another can indicate relationships between the symmetries and the weaving technique or the culture that produced them. This paper will also examine designs and patterns with color symmetry found in these textiles. The sample consisted of 588 repeated patterns and finite designs in textiles (389 plane, 166 frieze and 33 finite) culled from well known museums in the Philippines, personal collections of scholars, existing literature on Philippine textiles and field visits.
Organizational cynicism – what every manager needs to know
Authors: Thomas Nobin , Gupta Sonakshi
Published: March 2018

Purpose

The study aims to address what is organizational cynicism, review past literature to find out what leads to organizational cynicism, its consequences for organizations, and pinpoint practical implications for managers.

Design/methodology/approach

This review is prepared by an independent writer who has amalgamated several other voices from different researchers/scholars and finally, adds his own impartial comments and places the articles in context.

Findings

The effects of organizational cynicism on employees are strong and rising. The review points to the need for paying serious attention to the concept of “organizational cynicism”, which is an attitudinal negativity and if left unchecked, can cost the organization dearly. However, with interventions in place, perhaps, organizations can control the negative effects of organizational cynicism.

Originality/value

Based on a selective literature review, the article anchors on the change perspective of organizational cynicism and offers a number of learning and development implications for managers.
Improving resilience in high-risk organizations: principles for the design of innovative training situations
Authors: Flandin Simon , Poizat Germain , Durand Marc
Published: March 2018

Purpose

Safety and organizational research indicates that fostering resilience in organizations is a promising way for improving safety, albeit concrete means to implement resilience are still lacking, especially in the educational field. The purpose of this paper is to propose four principles for training design derived from past and current studies the authors conduct in high-risk organizations.

Design/methodology/approach

Training for resilience is considered within an enactive approach of human activity building on its properties of autonomy, structural coupling, self-organization, emergence, sensemaking, and metastability.

Findings

The article describes four educational design principles aiming at improving individual, collective, and organizational resilience: encourage mimetic experiences; pay attention to attention and concernedness; perturb and turn into an event; support participatory-sensemaking and collective sensemaking.

Research limitations/implications

The training program the authors propose may be challenging to assess. Besides, the most durable solutions to improve safety through resilience are to be found at the crossroad between organizational design and training/development policies. Future research should determine the implementability criteria which are likely to support the use of the principles the authors propose, and contribute to enrich this educational foundation.

Originality/value

Education and training are conceived herein as high-order means to improve safety through resilience in high-risk organizations, fostering the capacity of the operators and organization to develop efficiently and in the long run. We provide independent but complementary training principles that cannot be hierarchized, but that can be locally prioritized in organizations.
Impact of oil and gas price shocks on the non-performing loans of banks in an oil and gas-rich economy
Authors: Saif-Alyousfi Abdulazeez Y.H. , Saha Asish , Md-Rus Rohani
Published: March 2018

Purpose

The purpose of this paper is to examine and compare the impact of oil and gas prices shocks on the non-performing loans (NPLs) of banks at the aggregate as well as at the level of commercial and Islamic banks in Qatar over the period 2000-2016.

Design/methodology/approach

Using the West Texas Intermediate Database, BankScope Database, World Bank’s World Development Indicators Database, and International Monetary Fund Database, the authors use a one-step system generalized method of moments dynamic model to examine and compare the association between oil and gas prices shocks with NPLs in Qatari banks. The authors also test the hypotheses of direct and indirect impacts of oil price shocks and gas price shocks on bank NPLs.

Findings

The results indicate that oil price shocks and gas price shocks do not have directly affect NPLs of Qatari banks at the aggregate level, while they have indirect effects that are channeled through the country-specific macroeconomic and institutional factors. The authors find that oil and gas prices shocks affect NPLs of Qatari Islamic banks directly through extended oil and gas-related cash flows, while their impact on the NPLs of Qatari commercial banks is indirect. In other words, Islamic banks in Qatar greatly benefits from increased cash flow caused by the rise in the oil and gas prices, which make their NPLs, much lower than that in commercial banks. Better capital cushion, better managerial efficiency, better risk management, and liquidity management systems should be used by the Islamic banks in Qatar to expand their customer base. The authors also find that positive fiscal stance of the government reduces the NPLs in both commercial and Islamic banks.

Practical implications

The results of this study necessitate policy measures that can counter the effects of changes in oil and gas prices on the growth of bank NPLs.

Originality/value

It is widely recognized that oil and gas prices and the level of production are of great importance to the economic development of oil and gas-exporting countries. So far, however, no econometric study has been reported in the literature which analyses and compares the impact of oil and gas prices shocks on the NPLs of commercial and Islamic banks and also at the aggregate level in any of the oil economies. Thus, this study provides the first empirical evidence on distinct direct and indirect channels through which oil and gas prices shocks may affect bank NPLs.
Supporting property valuation with automatic reconciliation
Authors: d’Amato Maurizio
Published: March 2018

Purpose

Valuation is a professional activity based on international and local standards. In the valuation process more than one method can be modified. In this case, a final reconciliation of different opinions of value may be required. It is a matter of fact that the final result of these different valuation methods may vary. Therefore, in the final part of the valuation process, the valuer is required to assign a weight to the different methodologies to reach an appropriate opinion of value. This process is essentially based on valuer’s expertise. This paper aims to propose an automatic procedure of calculating the weights to assist the valuer in the valuation process.

Design/methodology/approach

The work provides methodologies to assign the weights through simple mathematical procedures that can be used to support subjective judgement in the valuation process. The models proposed can be applied to other phases of reconciliation inside the valuation process and are based on the collection of previous property data in the same market segment.

Findings

Two different methodologies are proposed to support valuers in the valuation process and in particular in the phase of the choice of the weights for final reconciliation purposes.

Research limitations/implications

The implication is the development of an information system to support the appraiser in providing these weights. The models proposed are only two but represent a future, much larger field of research.

Practical implications

The models may help in determining more consistent valuation reports.

Social implications

Consistent valuation reports for the determination of mortgage lending value may contribute to the stability of the social and economic system, especially after the 2008 non-agency mortgage crisis.

Originality/value

These are original models proposed in literature for such kind of problems.
CFTC announces new self-reporting and cooperation program
Authors: Bondi Bradley J. , Slovick David , Wheatley Michael
Published: March 2018

Purpose

To provide an overview of the Commodity Futures Trading Commission’s (CFTC’s) new self-reporting and cooperation program.

Design/methodology/approach

Summarizes the key features of the CFTC’s new cooperation program and the CFTC’s statement of its purpose in enacting the program; provides the authors’ views on the likely implications of the program for CFTC enforcement actions.

Findings

Whether the CFTC’s self-reporting and cooperation program will be a useful tool for deterring misconduct remains to be seen as the CFTC begins to implement it, but there are indications that it may encourage cooperation. If properly implemented, the program has the potential to benefit the CFTC and regulated parties significantly.

Originality/value

Practical insights on a new CFTC policy from experienced civil enforcement lawyers.
SEC focuses on initial coin offerings: tokens may be securities under federal securities laws
Authors: Senderowicz Jeremy I. , Grafton K. Susan , Spangler Timothy , Brown Kristopher D. , Schaffer Andrew J.
Published: March 2018

Purpose

To explain the recent determination by the US Securities and Exchange Commission (SEC) with respect to so-called “token sales” or “initial coin offerings” (ICOs) that some tokens may be securities under federal securities laws and to address other recent actions by the SEC with respect to ICOs.

Design/methodology/approach

Reviews the SEC’s determination that some tokens issued in an ICO may be securities under federal securities laws as outlined by the SEC’s Division of Enforcement in a “Report of Investigation Pursuant to Section 21(a) of the Securities Exchange Act of 1934: The DAO.” Provides overview of SEC Investor Alert, Investor Bulletin, and recent comments and actions of the Staff regarding investment in ICOs and provides guidance to those interested in participating in an ICO as an investor or issuer.

Findings

These actions by the SEC make it clear that the SEC is closely monitoring the market for ICOs, and that it wants potential investors and issuers to be aware that it is watching and may take action if it believes the securities laws have been violated.

Originality/value

Practical overview of recent developments and guidance from experienced securities and financial services lawyers.