bluuebunny/crossref_metadata_2025 huggingface dataset:
Countershading enhances camouflage by reducing prey contrast
Authors: Donohue Callum G. , Hemmi Jan M. , Kelley Jennifer L.
Published: May 2020

A three-dimensional body shape is problematic for camouflage because overhead lighting produces a luminance gradient across the body's surface. Countershading, a form of patterning where animals are darkest on their uppermost surface, is thought to counteract this luminance gradient and enhance concealment, but the mechanisms of protection remain unclear. Surprisingly, no study has examined how countershading alters prey contrast, or investigated how the presence of a dorsoventral luminance gradient affects detection under controlled viewing conditions. It has also been suggested that the direction of the dorsoventral luminance gradient (darkest or lightest on top) may interfere with predators' abilities to resolve prey's three-dimensional shape, yet this intriguing idea has never been tested. We used live fish predators (western rainbowfish,
Melanotaenia australis
) and computer-generated prey images to compare the detectability of uniformly pigmented (i.e. non-countershaded) prey with that of optimally countershaded prey of varying contrasts against the background. Optimally countershaded prey were difficult for predators to detect, and the probability and speed of detection depended on prey luminance contrast with the background. In comparison, non-countershaded prey were always highly detectable, even though their average luminance closely matched the luminance of the background. Our findings suggest that uniformly pigmented three-dimensional prey are highly conspicuous to predators because overhead lighting increases luminance contrast between different body parts or between the body and the background. We found no evidence for the notion that countershading interferes with predator perception of three-dimensional form.
Fire and grazing determined grasslands of central Madagascar represent ancient assemblages
Authors: Solofondranohatra Cédrique L. , Vorontsova Maria S. , Hempson Gareth P. , Hackel Jan , Cable Stuart , Vololoniaina Jeannoda , Lehmann Caroline E. R.
Published: May 2020

The ecology of Madagascar's grasslands is under-investigated and the dearth of ecological understanding of how disturbance by fire and grazing shapes these grasslands stems from a perception that disturbance shaped Malagasy grasslands only after human arrival. However, worldwide, fire and grazing shape tropical grasslands over ecological and evolutionary timescales, and it is curious Madagascar should be a global anomaly. We examined the functional and community ecology of Madagascar's grasslands across 71 communities in the Central Highlands. Combining multivariate abundance models of community composition and clustering of grass functional traits, we identified distinct grass assemblages each shaped by fire or grazing. The fire-maintained assemblage is primarily composed of tall caespitose species with narrow leaves and low bulk density. By contrast, the grazer-maintained assemblage is characterized by mat-forming, high bulk density grasses with wide leaves. Within each assemblage, levels of endemism, diversity and grass ages support these as ancient assemblages. Grazer-dependent grasses can only have co-evolved with a now-extinct megafauna. Ironically, the human introduction of cattle probably introduced a megafaunal substitute facilitating modern day persistence of a grazer-maintained grass assemblage in an otherwise defaunated landscape, where these landscapes now support the livelihoods of millions of people.
Exceptional but vulnerable microbial diversity in coral reef animal surface microbiomes
Authors: Chiarello Marlène , Auguet Jean-Christophe , Graham Nicholas A. J. , Claverie Thomas , Sucré Elliott , Bouvier Corinne , Rieuvilleneuve Fabien , Restrepo-Ortiz Claudia Ximena , Bettarel Yvan , Villéger Sébastien , Bouvier Thierry
Published: May 2020

Coral reefs host hundreds of thousands of animal species that are increasingly threatened by anthropogenic disturbances. These animals host microbial communities at their surface, playing crucial roles for their fitness. However, the diversity of such microbiomes is mostly described in a few coral species and still poorly defined in other invertebrates and vertebrates. Given the diversity of animal microbiomes, and the diversity of host species inhabiting coral reefs, the contribution of such microbiomes to the total microbial diversity of coral reefs could be important, yet potentially vulnerable to the loss of animal species. Analysis of the surface microbiome from 74 taxa, including teleost fishes, hard and soft corals, crustaceans, echinoderms, bivalves and sponges, revealed that more than 90% of their prokaryotic phylogenetic richness was specific and not recovered in surrounding plankton. Estimate of the total richness associated with coral reef animal surface microbiomes reached up to 2.5% of current estimates of Earth prokaryotic diversity. Therefore, coral reef animal surfaces should be recognized as a hotspot of marine microbial diversity. Loss of the most vulnerable reef animals expected under present-day scenarios of reef degradation would induce an erosion of 28% of the prokaryotic richness, with unknown consequences on coral reef ecosystem functioning.
“Clinical, Radiological and Therapeutic Characteristics of Patients with COVID-19 in Saudi Arabia”
Authors: Shabrawishi Mohammed , Al-Gethamy Manal M , Naser Abdallah Y , Ghazawi Maher A , Alsharif Ghaidaa F , Obaid Elaf F , Melebari Haitham A , Alamri Dhaffer M , Brinji Ahmad S , Al Jehani Fawaz H , Almaimani Wail , Ekram Rakan A , Alkhatib Kasim H , Alwafi Hassan
Published: May 2020

BACKGROUND

Coronavirus disease 2019 (COVID-19) is a rapidly spreading global pandemic. The clinical characteristics of COVID-19 has been reported; however, there are limited researches that investigated the clinical characteristics of COVID-19 in the Middle East. The aim of this study is to investigate the clinical, radiological and therapeutic characteristics of patients diagnosed with COVID19 in Saudi Arabia.

METHODS

This study is a retrospective single-centre case series study. We extracted data for patients who were admitted to the Al-Noor Specialist hospital with a PCR confirmed SARS-COV-2 between 12th and 31st of March 2020. Descriptive statistics were used to describe patients’ characteristics. Continuous data were reported as mean ± SD. Chi-squared test/Fisher test were used as appropriate to compare proportions for categorical variables.

RESULTS

A total of 150 patients were hospitalised for COVID-19 during the study period. The mean age was 46.1 years (SD: 15.3 years). Around 61.0% (n= 90) were males and six patients (3.9%) reported working in the healthcare sector. The most common comorbidities were hypertension (28.8%, n= 42) and diabetes mellitus (26.0%, n= 38). The majority of the patients, 64.4% (n = 96) had a recent contact history with a COVID patient. Regarding the severity of the hospitalised patients, 105 patients (70.0%) were mild, 29 (19.3%) were moderate, and 16 patients (10.7%) were severe or required ICU care. From the 105 mild patients, around 31.3% (n= 47) were asymptomatic.

CONCLUSION

This case series provides clinical, radiological and therapeutic characteristics of hospitalised patients with confirmed COVID-19 in Saudi Arabia.
Facemasks prevent influenza-like illness: implications for COVID-19
Authors: Wei Jie , Doherty Michael , Persson Monica S.M. , Sarmanova Aliya , Swain Subhashisa , Kuo Changfu , Zeng Chao , Lei Guanghua , Zhang Weiya
Published: May 2020

The coronavirus disease 2019 (COVID-19) pandemic is causing a huge toll on individuals, families, communities and societies across the world. Currently, whether wearing facemasks in public should be a measure to prevent transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) remains contraversial.1 This is largely because there have been no randomized controlled trials (RCTs) for coronavirus to directly support this. However, lessons may be taken from published RCTs examining influenza-like illness (ILI).2,3 Recent studies suggested that SARS-CoV-2 shares similar transmission route with influenza virus,4 and the incidence of community transmission of SARS-CoV-2 in individuals with ILI is high.5 Therefore, we undertook this meta-analysis of RCTs examining the efficacy of wearing facemasks to prevent ILI in community settings, irrespective of confirmatory testing for the causative virus.

We undertook a systematic literature search for RCTs related to facemasks and ILI between 1966 and April 2020 using PUBMED, EMBASE, and Cochrane library. RCTs undertaken in community (not hospital) settings comparing wearing and not wearing facemasks for ILI were included. Incidence of ILI (e.g., fever, cough, headache, sore throat, aches or pains in muscles or joints) was estimated per group. Relative risk (RR) and 95% confidence interval (CI) were calculated.

We screened 899 related abstracts and eventually included 8 RCTs (Figure S1). Basic characteristics and quality of included RCTs are listed in Supplement. Participants wearing facemasks had a significantly lower risk of developing ILI than those not wearing facemasks (pooled RR=0.81, 95% CI: 0.70–0.95) and there was no heterogeneity (Figure 1). The decreased risk of ILI was more pronounced if everyone wore facemask irrespective of whether they were infected or not (RR=0.77, 95% CI: 0.65-0.91), compared to those wearing facemasks when infected (RR=0.95, 95% CI: 0.58-1.56) or uninfected (RR=1.26, 95% CI: 0.69-2.31).

This study shows that wearing facemasks, irrespective of infection status, is effective in preventing ILI spread in the community. This situation mirrors what is happening now in public settings where we do not know who has been infected and who has not. Although there are no RCTs of facemasks for SARS-CoV-2, as with other simple measures such as social distancing and handwashing, these data support the recommendation to wear facemasks in public to further reduce transmission of SARS-CoV-2 and flatten the curve of this pandemic, especially when social distancing is impractical, such as shopping, or travelling with public transport for work that cannot be done from home.
Expression of the long noncoding RNA DINO in HPV positive cervical cancer cells reactivates the dormant TP53 tumor suppressor through ATM/CHK2 signaling
Authors: Sharma Surendra , Munger Karl
Published: May 2020

Tumor cells overcome the cytostatic and cytotoxic restraints of TP53 tumor suppressor signaling through a variety of mechanisms. High-risk human papillomavirus (HPV) positive tumor cells retain wild type TP53 because the HPV E6/UBE3A ubiquitin ligase complex targets TP53 for proteasomal degradation. While restoration of TP53 in tumor cells holds great promise for cancer therapy, attempts to functionally restore the dormant TP53 tumor suppressor in HPV positive cancer cells by inhibiting the HPV E6/UBE3A ubiquitin ligase complex have not yet been successful. The Damage Induced long noncoding RNA, DINO, (DINOL) is a TP53 transcriptional target that has been reported to bind to and stabilize TP53, thereby amplifying TP53 signaling. We show that HPV positive cervical carcinoma cells contain low levels of DINO because of HPV E6/UBE3A mediated TP53 degradation. Acute DINO expression overrides HPV16 E6/UBE3A mediated TP53 degradation, causing TP53 stabilization and increased expression of TP53 transcriptional target genes. This causes a marked sensitization to chemotherapy agents and renders cells vulnerable to metabolic stress. Acute DINO expression in HPV positive cervical cancer cells induces hallmarks of DNA damage response signaling and TP53 activation involves ATM/CHK2 signaling. DINO upregulation in response to DNA damage is independent of ATM/CHK2 and can occur in cancer cells that express mutant TP53.

IMPORTANCE

Functional restoration of the TP53 tumor suppressor holds great promise for anti-cancer therapy. Current strategies are focused on modulating TP53 regulatory proteins. Long noncoding RNAs (lncRNAs) have emerged as important regulators of TP53 as well as modulators of downstream tumor suppressive transcriptional responses. Unlike many other cancer types, human papillomavirus (HPV) positive cancer cells retain wild type TP53 that is rendered dysfunctional by the viral E6 protein. We show that acute expression of the Damage Induced long Noncoding RNA, DINO, a known TP53 transcriptional target and functional modulator, causes TP53 reactivation in HPV positive cervical cancer cells. This causes increased vulnerability to standard chemotherapeutics as well as biguanide compounds that cause metabolic stress. Hence, strategies that target DINO may be useful for restoring TP53 tumor suppressor activity in HPV positive cancers and other tumor types that retain wild type TP53.
Mental Health Status among the South Indian Pharmacy Students during Covid-19 Pandemic’s Quarantine Period: A Cross-Sectional Study
Authors: Vidyadhara S , Chakravarthy A , Kumar A Pramod , Harsha C Sri , Rahul R
Published: May 2020

Introduction

The COVID-19 outbreak created a major panic among all the citizens of the country owing to its severity, contagiousness within the community, lack of specific treatment and possibility of re-infection. All these factors along with the uncertain behaviour of the virus lead to state of fear and concern all throught out the nation. The current study represents the mental health survey conducted on the students of South Indiaafter the completion of one month quarantine period of the COVID-19 outbreak.

Methodology

The present study is a cross-sectional, web-based online survey which consists of 21-item DASS questionnaire. Thiswas used to assess the emotional states of depression, anxiety, and stress. Using Google Forms, the questionnaire was randomly distributed among the pharmacy students of selected colleges. Mean with standard deviation was calculated for continuous variables and the number with percentage was calculated for categorical variables.

Results

A total of 500 participants responded to the questionnaire. More than half of the responses were received from females (65%). On assessment it was found that, 26 % of respondents reported severe to extremely severe depressive symptoms; 31.5 % of respondents reported severe to extremely severe anxiety symptoms, and 19 % reported severe to extremely severe stress levels.

Conclusion

In India during the outbreak of COVID-19, an alarming number of students were found to have an impact on mental health due to the outbreak and were observed to have higher levels of stress, anxiety, and depression. The study findings shows the need of conducting more such studies and can be used to prepare appropriate psychological interventions to improvemental health among the young public during the pandemic.
Predicting Long-term Evolution of COVID-19 by On-going Data using Bayesian Susceptible-Infected-Removed Model
Authors: Hidaka Shohei , Torii Takuma
Published: May 2020

In this study, we propose a novel statistical method to predict a long-term epidemic evolution based on a on-going data. We developed a Bayesian framework for the Susceptible-Infected-Removed model (Bayesian SIR), and estimated its underlying parameters based on day-by-day timeseries of the cumulative number of infectious individuals. The new Baysian framework extends the deterministic SIR model to a probabilistic form, which provides an accurate estimation of the underlying system by a short and noisy data. We applied it to the data reported on the Coronavirus Disease 2019 (COVID-19), and made a month long prediction on its evolution. Our simulated test using past timeseries to predict the current data gives a reasonable reliablity of the proposed method. Our analysis of the current data detected and warned a rising trend in the countries in Central Asia, Middle East, and South America, while United States or European countries, which have already experienced large numbers of infected cases, are predicted to slow down in the increase.
Capsid integrity quantitative PCR to determine virus infectivity in environmental and food applications – a systematic review
Authors: Leifels Mats , Dan Cheng , Sozzi Emanuele , Shoults David C. , Wuertz Stefan , Mongkolsuk Skorn , Sirikanchana Kwanrawee
Published: May 2020

Capsid-integrity quantitative PCR (qPCR), a molecular detection method for infectious viruses combining azo-dye pretreatment with qPCR, has been widely used in recent years; however, variations in pretreatment conditions for various virus types can limit the efficacy of specific protocols. By identifying and critically synthesizing forty-two recent peer-reviewed studies employing capsid-integrity qPCR for viruses in the last decade (2009 to 2019) in the fields of food safety and environmental virology, we aimed to establish recommendations for the detection of infectious viruses. Intercalating dyes are effective measures of viability in PCR assays provided the viral capsid is damaged; viruses that have been inactivated by other causes, such as loss of attachment or genomic damage, are less well detected using this approach. Although optimizing specific protocols for each virus is recommended, we identify a framework for general assay conditions. These include concentrations of ethidium monoazide, propidium monoazide or its derivates between 10 and 200 µM; incubation on ice or at room temperature (20 - 25°C) for 5 to 120 min; and dye activation using LED or high light (500 – 800 Watts) exposure for periods ranging from 5 to 20 min. These simple steps can benefit the investigation of infectious virus transmission in routine (water) monitoring settings and during viral outbreaks such as the current COVID-19 pandemic or endemic diseases like dengue fever.

Graphical abstract
Using epidemic simulators for monitoring an ongoing epidemic
Authors: Raghavan Mohan , Sridharan Kousik Sarathy , Yashaswini M R
Published: May 2020

Prediction of infection trends, estimating the efficacy of contact tracing, testing or impact of influx of infected are of vital importance for administration during an ongoing epidemic. Most effective methods currently are empirical in nature and their relation to parameters of interest to administrators are not evident. We thus propose a modified SEIRD model that is capable of modeling effect of interventions and in migrations on the progress of an epidemic. The tunable parameters of this model bear relevance to monitoring of an epidemic. This model was used to show that some of the commonly seen features of cumulative infections in real data can be explained by piece wise constant changes in interventions and population influx. We also show that the data of cumulative infections from twelve Indian states between mid March and mid April 2020 can be generated from the model by applying interventions according to a set of heuristic rules. Prediction for the next ten days based on this model, reproduced real data very well. In addition, our model also reproduced the time series of recoveries and deaths. Our work constitutes an important first step towards an effective dashboard for the monitoring of epidemic by the administration, especially in an Indian context.
Adverse events of colonoscopy in a colorectal cancer screening programme with faecal immunochemical test: a population-based community-based observational study
Authors: Denis Bernard , Gendre Isabelle , Weber Sarah , Perrin Philippe
Published: May 2020

Objectives

Colonoscopy is considered a safe examination, serious complications being uncommon. Our study aimed to assess the adverse events of colonoscopy in a colorectal cancer screening programme with faecal immunochemical test (FIT) and to compare them with those of a previous programme with guaiac-based faecal occult blood test (gFOBT).

Design

Retrospective observational study

Setting

Population-based community-based colorectal cancer screening programme organised in Alsace, part of the national French programme, with FIT from 2015 to 2018 and gFOBT from 2003 to 2014.

Participants

All residents aged 50 – 74 years having a colonoscopy performed for a positive FOBT.

Main outcome measures

Adverse events were recorded through prospective voluntary reporting by community gastroenterologists and retrospective postal surveys addressed to persons screened.

Results

Of 9576 colonoscopies performed for a positive FIT, 6194 (64.7%) were therapeutic. Overall, 180 adverse events were recorded (18.8‰, 95% CI 16.1-21.5), 114 of them (11.9‰, 95% CI 9.7-14.1) requiring hospitalisation, 55 (5.7‰, 95% CI 4.2-7.3) hospitalisation >24hrs, and 8 (0.8‰, 95% CI 0.3-1.4) surgery. The main complications requiring hospitalisation were perforation (n=18, 1.9‰, 95% CI 1.0-2.7) and bleeding (n=31, 3.2‰, 95% CI 2.1-4.4). We observed one death (1 / 27,000 colonoscopies). Overall, 52 persons harbouring at least one adenoma ≥ 10 mm were detected for one adverse event requiring hospitalisation >24hrs. The rate of adverse events remained stable between gFOBT and FIT programmes.

Conclusions

The harms of colonoscopy in a colorectal cancer screening programme with FIT are more frequent than usually estimated, here six adverse events requiring hospitalisation >24hrs (three bleedings, two perforations), one necessitating surgery and 50 minor complications per 1000 colonoscopies. The price to be paid to save lives through colorectal cancer screening programmes is higher than what is stated in most pilots. Today, comparison between series dealing with colonoscopy-related adverse events is almost impossible.
Skin protective effects of RM191A, a novel superoxide dismutase mimetic
Authors: Shariev Artur , Laos Alistair J. , Lai Donna , Hua Sheng , Zinger Anna , McRae Christopher R. , Casbolt Llewellyn S. , Combes Valery , Hung Tzong-tyng , Dixon Katie M. , Thordarson Pall , Mason Rebecca S. , Das Abhirup
Published: May 2020

Superoxide dismutase (SOD) is known to be protective against oxidative stress-mediated skin dysfunction. Here we explore the potential therapeutic activities of RM191A, a novel SOD mimetic, on skin. RM191A is a water soluble, dimeric copper (Cu2+-Cu3+)-centred polyglycine coordination complex. It displays 10-fold higher superoxide quenching activity compared to SOD as well as significant anti-inflammatory activity through beneficial modulation of several significant inflammatory pathways in cells.

We tested the therapeutic potential of RM191A in a topical gel using a human skin explant model and observed that it significantly inhibits UV-induced DNA damage in the epidermis and dermis, including cyclobutane pyrimidine dimers (CPD), 8-oxo-guanine (8-oxoG) and 8-nitroguanine (8NGO). RM191A topical gel is found to be safe and non-toxic in mice following month-long daily dosing at 0.19 mL/kg body weight. Moreover, it significantly accelerates excisional wound healing, and reduces 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced skin inflammation in mice.

Highlights

Superoxide dismutase mimetic RM191A is a highly stable copper (Cu2+-Cu3+)-polyglycine coordination complex

RM191A exhibits potent antioxidant (10-fold more than that of superoxide dismutase) propertiesin vitro

RM191A exhibits potent anti-inflammatory propertiesin vitroandin vivo

RM191A protects human skin explants against UV-induced oxidative stress and DNA damage

RM191A is non-toxic and readily bioavailable in mice

RM191A attenuates TPA-induced skin inflammation and improves wound healing in mice
Changes in electrophysiological static and dynamic human brain functional architecture from childhood to late adulthood
Authors: Coquelet N , Wens V , Mary A , Niesen M , Puttaert D , Ranzini M , Vander Ghinst M , Bourguignon M , Peigneux P , Goldman S , Woolrich M , De Tiège X
Published: May 2020

This magnetoencephalography study aimed at characterizing age-related changes in resting-state functional brain organization from mid-childhood to late adulthood. We investigated neuromagnetic brain activity at rest in 105 participants divided into three age groups: children (6–9 years), young adults (18–34 years) and healthy elders (53–78 years). The effects of age on static resting-state functional integration were assessed using band-limited power envelope correlation, whereas those on transient functional dynamics were disclosed using hidden Markov modeling of power envelope activity. Brain development from childhood to adulthood came with (i) a strengthening of functional integration within and between resting-state networks and (ii) an increased temporal stability of transient (100–300 ms lifetime) and recurrent states of network activation or deactivation mainly encompassing lateral or medial associative neocortical areas. Healthy aging was characterized by decreased static resting-state functional integration and dynamical stability within the visual network. These results based on electrophysiological measurements free of neurovascular biases suggest that functional brain integration mainly evolves during brain development, with limited changes in healthy aging. These novel electrophysiological insights into human brain functional architecture across the lifespan pave the way for future clinical studies investigating how brain disorders affect brain development or healthy aging.
Predicting Cortical Signatures of Consciousness using Dynamic Functional Connectivity Graph-Convolutional Neural Networks
Authors: Grigis Antoine , Gomez Chloé , Tasserie Jordy , Ambroise Corentin , Frouin Vincent , Jarraya Béchir , Uhrig Lynn
Published: May 2020

Decoding the levels of consciousness from cortical activity recording is a major challenge in neuroscience. Using clustering algorithms, we previously demonstrated that resting-state functional MRI (rsfMRI) data can be split into several clusters also called “brain states” corresponding to “functional configurations” of the brain. Here, we propose to use a selfsupervised machine learning method based on artificial neural networks to predict functional brain states across levels of consciousness from rsfMRI. The Functional Connectivity (FC) matrices reflect the brain-state dynamic at a given time. Because it is key to consider the FC topologies, a specific graph-Convolutional Neural Network (gCNN), namely BrainNetCNN, is considered to predict the brain states in awake and anesthetized nonhuman primates. To avoid the circularity that remains in the training stage, where the target is composed of pseudo-labels, recent self-supervised techniques are implemented. Using a linear probe for the prediction, the network achieves a prediction accuracy consistent with state-of-the-art methods lying in [0.655, 0.759] depending on the experimental settings. To put forward the interest of such a representation, the transition probabilities and the set of connections found to be important for predicting a brain state are computed. This latter is directly linked with the level of consciousness. The results demonstrate that deep learning methods are not only able to predict brain states but also provide additional insight into cortical signatures of consciousness with potential clinical consequences for the monitoring of anesthesia and the diagnosis of disorders of consciousness.
Characterization of an α-glucosidase enzyme conserved inGardnerellaspp. isolated from the human vaginal microbiome
Authors: Bhandari Pashupati , Tingley Jeffrey P. , Palmer David R. J. , Abbott D. Wade , Hill Janet E.
Published: May 2020

Gardnerellaspp. in the vaginal microbiome are associated with bacterial vaginosis, a dysbiosis in which a lactobacilli dominant microbial community is replaced with mixed aerobic and anaerobic bacteria includingGardnerellaspecies. The co-occurrence of multipleGardnerellaspecies in the vaginal environment is common, but different species are dominant in different women. Competition for nutrients, particularly glycogen present in the vaginal environment, could play an important role in determining the microbial community structure. Digestion of glycogen into products that can be taken up and further processed by bacteria requires the combined activities of several enzymes collectively known as amylases, which belong to glycoside hydrolase family 13 (GH13) within the CAZy classification system. GH13 is a large and diverse family of proteins, making prediction of their activities challenging. SACCHARIS annotation of the GH13 family inGardnerellaresulted in identification of protein domains belonging to eight subfamilies. Phylogenetic analysis of predicted amylase sequences from 26Gardnerellagenomes demonstrated that a putative α-glucosidase-encoding sequence, CG400_06090, was conserved in all species in the genus. The predicted α-glucosidase enzyme was expressed, purified and functionally characterized. The enzyme was active on a variety of maltooligosaccharides over a broad pH range (4.0 - 8) with maximum activity at pH 7. TheKm,kcatandkcat/Kmvalues for the substrate 4-nitrophenyl α-D-glucopyranoside were 8.3 μM, 0.96 min-1and 0.11 μM-1min-1respectively. Glucose was released from maltose, maltotriose, maltotetraose and maltopentaose, but no products were detected on thin layer chromatography when the enzyme was incubated with glycogen. Our findings show thatGardnerellaspp. produce an α-glucosidase enzyme that may contribute to the complex and multistep process of glycogen metabolism by releasing glucose from maltooligosaccharides.
Inhibition of mitochondrial respiration impairs nutrient consumption and metabolite transport in human retinal pigment epithelium
Authors: Zhang Rui , Engel Abbi L , Wang Yekai , Li Bo , Shen Weiyong , Gillies Mark C , Chao Jennifer , Du Jianhai
Published: May 2020

Mitochondrial respiration in mammalian cells not only generates ATP to meet their own energy needs but also couples with biosynthetic pathways to produce metabolites that can be exported to support neighboring cells. However, how defects in mitochondrial respiration influence these biosynthetic and exporting pathways remains poorly understood. Mitochondrial dysfunction in retinal pigment epithelium (RPE) cells is an emerging contributor to the death of their neighboring photoreceptors in degenerative retinal diseases including age-related macular degeneration. In this study, we used targeted-metabolomics and13C tracing to investigate how inhibition of mitochondrial respiration influences the intracellular and extracellular metabolome. We found inhibition of mitochondrial respiration strikingly influenced both the intracellular and extracellular metabolome in primary RPE cells. Intriguingly, the extracellular metabolic changes sensitively reflected the intracellular changes. These changes included substantially enhanced glucose consumption and lactate production, reduced release of pyruvate, citrate and ketone bodies, and massive accumulation of multiple amino acids and nucleosides. In conclusion, these findings reveal a metabolic signature of nutrient consumption and release in mitochondrial dysfunction in RPE cells. Testing medium metabolites provides a sensitive and noninvasive method to assess mitochondrial function in nutrient utilization and transport.
Differential Cetacea Circadian Rhythmicity is associated with the molecular erosion of Cortistatin
Authors: Valente Raul , Alves Luís Q. , Nabais Matilde , Alves Filipe , Sousa-Pinto Isabel , Ruivo Raquel , Castro L. Filipe C.
Published: May 2020

The ancestors of Cetacea underwent profound morpho-physiological alterations. By displaying an exclusive aquatic existence, cetaceans evolved unique patterns of locomotor activity, vigilant behaviour, thermoregulation and circadian rhythmicity. Deciphering the molecular landscape governing many of these adaptations is key to understand the evolution of phenotypes. Here, we investigate Cortistatin (CORT), a neuropeptide displaying an important role mammalian biorhythm regulation. This neuropeptide is a known neuroendocrine factor, stimulating slow-wave sleep, but also involved in the regulation of energy metabolism and hypomotility inducement. We assessed the functional status ofCORTin 139 mammalian genomes (25 orders), including 30 species of Cetacea. Our findings indicate that cetaceans and other mammals with atypical biorhythms, thermal constraints and/or energy metabolism, have accumulated deleterious mutations inCORT. In light of the pleiotropic action of this neuropeptide, we suggest that this inactivation contributed to a plethora of phenotypic adjustments to accommodate adaptive solutions to specific ecological niches.
A chemical screen identifies a link between lipid metabolism and mRNA translation
Authors: Corman Alba , Kanellis Dimitris C. , Häggblad Maria , Lafarga Vanesa , Bartek Jiri , Carreras-Puigvert Jordi , Fernandez-Capetillo Oscar
Published: May 2020

mRNA translation is one of the most energy-demanding processes for living cells, alterations of which have been frequently documented in human disease. Using recently developed technologies that enable image-based quantitation of overall translation levels, we here conducted a chemical screen to evaluate how medically approved drugs, as well as drugs that are currently under development, influence overall translation levels. Consistent with current knowledge, inhibitors of the mTOR signaling pathway were the most represented class among translation suppresors. In addition, we identified that inhibitors of sphingosine kinases (SPHKs) also reduce mRNA translation levels independently of mTOR. Mechanistically this is explained by an effect of the compounds on the membranes of the endoplasmic reticulum, which activates the integrated stress response (ISR). Accordingly, the impact of SPHK inhibitors on translation is alleviated by the concomitant inhibition of ISR kinases. On the other hand, and despite the large number of molecules tested, our study failed to identify chemicals capable of substantially increasing mRNA translation, raising doubts on to what extent translation can be supra-physiologically stimulated in mammalian cells. In summary, our study provides the first comprehensive characterization of the effect of known drugs on protein translation and has helped to unravel a new link between lipid metabolism and mRNA translation in human cells.
Levô in fimo test – A simple test for fecal microbial reconstituted mice
Authors: Aalam SM Musheer , Gamb Scott I , Kashyap Purna , Kannan Nagarajan
Published: May 2020

Here we report the first method for rapid on-site monitoring of germfree C57BL/6 mice colonized with feces from conventionally raised mice. The method, namedlevô in fimotest, readily distinguishes feces from germfree mice and conventionalized germfree mice based on its properties to float or sink in Trump’s fixative solution. We validated the test using feces from conventionally raised mice, germfree mice and conventionalized germfree mice, and cross-validated using multiple indicators of microbial presence in feces. Levô in fimo test is a simple, cost-effective, instant yet robust method for on-site monitoring of gut microbial reconstitution in germfree mice.
Diammonium potassium citrate, (NH4)2KC6H5O7
Authors: Patel Nilan V. , Golab Joseph T. , Kaduk James A.
Published: May 2020

The crystal structure of diammonium potassium citrate, 2NH4
+·K+·C6H5O7
3−, has been solved and refined using laboratory X-ray powder diffraction data and optimized using density functional theory. The KO7 coordination polyhedra are isolated. The ammonium cations and the hydrophobic methylene sides of the citrate anions occupy the spaces between the coordination polyhedra. Each hydrogen atom of the ammonium ions acts as a donor in a charge-assisted N—H...O, N—H...(O,O) or N—H...(O,O,O) hydrogen bond. There is an intramolecular O—H...O hydrogen bond in the citrate anion between the hydroxide group and one of the terminal carboxylate groups.
Rheological behaviors of silver conductive pastes with ethyl cellulose
Authors: Hsiang Hsing-I. , Chen Chih-Cheng , Fan Liang-Fang , Cheng Hao-Yin
Published: May 2020

Purpose

The interaction between the silver powder and organic vehicle largely determines the rheological behavior of silver conductive paste. This study aims to prepare silver conductive paste with an organic vehicle system consisting of ethyl cellulose (EC) and terpineol/butyl carbitol acetate solvent mixtures. The study also aims to measure the rheological behaviors of the silver conductive pastes with different solvent mixtures, EC molecular weights and silver content, to investigate the interaction among the polymer, solvent and silver powder and determine the main factors affecting the thixotropic index and maximum silver content.

Design/methodology/approach

The rheological behaviors of silver conductive pastes with different solvent mixtures, EC molecular weights and silver content were investigated using viscometer.

Findings

The shear thinning became significant with increasing EC molecular weight. The EC solvation with higher molecular weight in solvent is better than that of EC with lower molecular weight. This leads to a stronger interaction between the silver powder and EC with higher molecular weight and consequently good silver particle dispersion. The relative viscosity of silver conductive paste at 10 s−1 increases significantly with increasing silver content, but the relative viscosity at 100 s−1 is much less sensitive to the silver content. The viscosities at low and high shear rate can be increased by increasing the silver content and EC molecular weight, respectively.

Originality/value

The interaction among the polymer, solvent and silver powder was investigated for the silver paste with high solid content. The main factors affecting the viscosities at high and low shear rates, thixotropic index and maximum silver content were determined.
The impact of sewing thread's tensile behavior and laundering process on the seam puckering of elastic and normal fabrics
Authors: Kamali Reyhaneh , Mesbah Yasaman , Mousazadegan Fatemeh
Published: May 2020

Purpose

The aim of the present study is to consider the influence of the tensile behavior of fabric and sewing thread on the seam appearance.

Design/methodology/approach

In this study, the formation of seam puckering on two elastic and normal woven fabrics was explored. In order to prepare samples, various sewing threads were applied. Test specimens were sewn under five different thread tension levels. Then the appearance of samples was evaluated subjectively to determine their seam puckering grade before and after the laundering process.

Findings

The obtained outcomes of this study present that although sewing thread tension increment decreases the seam pucker ranking in the similar sewing condition, elastic fabrics have a greater seam pucker grade compared to the normal fabric due to the fabric extension and contraction during sewing and after sewing process, respectively. In addition, the elastic strain of the sewing thread is the key factor that determined sewing thread's tendency to make seam puckering. Moreover, the laundry process due to the relaxation of the sewing thread decreases the seam pucker grade.

Originality/value

The consistency of the tensile property of fabric and sewing thread is a crucial parameter in improving the seam appearance and obtaining a smooth seam.
Secondary school structure, organisational learning capacity and learning organisations: a systemic contribution
Authors: Barnard Peter A.
Published: May 2020

Purpose

The purpose of this paper is to explain the influence of a school's operational structure on organisational learning capacity (OLC), and how this either supports or disables any aspiration as a learning organisation.

Design/methodology/approach

Two organisational working models are described, one based on same-age structure and another that uses multi-age organisation. These are systemically examined to test for OLC and subsequent potential to develop as learning organisations.

Findings

Schools using same-age organisational structure have restricted feedback mechanisms that inhibit their ability to develop OLC. Schools that have adopted multi-age structures have extensive information feedback mechanisms; consequently, they have a higher OLC and the potential to develop as a quasi learning organisation.

Practical implications

This paper intervenes at a time when interest in the concepts of OLC, transformative learning, and the idea developing schools as learning organisations is increasing. The danger of this development is to repeat the reformational mistakes of the past by failing to reflect on ingrained organisational assumptions. This paper encourages schools to reflect on their organisational strategy.

Originality/value

This paper fills a gap in the research literature by offering a practical analysis of two organisational systems, to show how structure impacts on OLC and aspirations to develop as a learning organisation.
Interpersonal and IT-enabled communication in platform transactions: the contingent role of contract completeness and technology usage
Authors: Yang Qian , Qian Liping , Zhao Xiande
Published: May 2020

Purpose

This paper assesses whether communication via interpersonal and IT channels accounts for short-term financial performance and long-term orientation and how these effects are influenced by contract completeness and technology usage in platform builder-platform participant relationships.

Design/methodology/approach

The conceptual model and hypotheses are validated through a moderated regression of 384 survey responses from platform participant.

Findings

The empirical results indicate that interpersonal and IT-enabled communication contribute to both short-term financial gains and long-term orientation. The coexistence of interpersonal communication and IT-enabled communication has a synergetic effect on long-term orientation. Contract completeness positively moderates the effect of interpersonal communication on short-term performance while negatively moderating its effect on long-term orientation. Furthermore, contract completeness undermines the effect of IT-enabled communication on short-term performance. Technology usage enhances the effectiveness of interpersonal communication in generating long-term orientation.

Originality/value

First, diverging from the extant research treating communication as a single dimension construct, this study differentiates communication on media channels and shows their separate and synergetic effects on short-term performance and long-term orientation. Second, our empirical findings indicate that the effects of communication are influenced by governance practices, which extends the communication literature. Third, previous studies have presented conflicting results concerning the role of governance mechanisms in inter-firm relationships. By showing that governance mechanisms also either support or suppress communication in generating performance for platform participants, this study extends the existing research on governance mechanisms. Finally, by regarding technology usage as a transactional governance mechanism, this study furthers our understanding of the role of technology in interfirm relationships.
The yin and yang nature of coopetition activities: non-linear effects and the moderating role of competitive intensity for internationalised firms
Authors: Crick James M. , Crick Dave
Published: May 2020

Purpose

This paper draws upon the Yin and Yang concept of Chinese philosophy within a Western context to examine coopetition, namely, the interplay between cooperation and competition. Although coopetition activities should positively affect company performance, earlier research involving this relationship has typically been linear in nature and without moderating factors. Consequently, underpinned by resource-based theory and the relational view, the purpose of this investigation is to examine the non-linear (inverted U-shaped) link between coopetition and company performance under the moderating role of competitive intensity.

Design/methodology/approach

Collection of survey data involved a sample of 101 internationalising wine producers in New Zealand. Following a check of the statistical data for all major assessments of reliability and validity (together with common method variance), testing the research hypotheses and control paths took place through hierarchical regression. Furthermore, 20 semi-structured interviews helped explain the underlying mechanisms behind the quantitative results.

Findings

Coopetition had a non-linear (inverted U-shaped) relationship with market performance. Surprisingly, competitive intensity yielded a negative moderation effect. The mixed methods results highlighted that firms must strike an effective balance between the paradoxical forces of cooperativeness and competitiveness across their product-market strategies.

Originality/value

This investigation contributes to the existing literature by developing and testing a conceptual framework examining the nature of the relationship between coopetition activities and market performance – using non-linear (inverted U-shaped) and moderating effects. It addresses a debate between two schools-of-thought concerning the impact of competitive intensity on the coopetition paradox. Additionally, this study helps to explain the coopetition construct through the Yin and Yang concept to highlight how the paradoxical forces of cooperativeness and competitiveness can create harmful outcomes for organisations if they do not manage them effectively (across domestic and international markets).
Exploring the mechanism of social media addiction: an empirical study from WeChat users
Authors: Cao Xiongfei , Gong Mingchuan , Yu Lingling , Dai Bao
Published: May 2020

Purpose

The problematic use of social media progressively worsens among a large proportion of users. However, the theory-driven investigation into social media addiction behavior remains far from adequate. Among the countable information system studies on the dark side of social media, the focus lies on users' subjective feelings and perceived value. The technical features of the social media platform have been ignored. Accordingly, this study explores the formation of social media addiction considering the perspectives of users and social mediaper seon the basis of extended motivational framework and attachment theory.

Design/methodology/approach

This study investigates the formation of social media addiction with particular focus on WeChat. A field survey with 505 subjects of WeChat users was conducted to investigate the research model.

Findings

Results demonstrate that social media addiction is determined by individuals' emotional and functional attachment to the platform. These attachments are in turn influenced by motivational (perceived enjoyment and social interaction) and technical (informational support, system quality and personalization) factors.

Originality/value

First, this study explains the underlying mechanism of how users develop social media addiction. Second, it highlights the importance of users' motivations and emotional dependence at this point. It also focuses on the technical system of the platform that plays a key role in the formation of addictive usage behavior. Third, it extends attachment theory to the context of social media addictive behavior.